Download SICB 2009 Annual Meeting Abstracts

Poster Abstracts
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P1.109 AAMIDOR, Sarah E*; BAUCHINGER, Ulf; PINSHOW, Berry;
Ben-Gurion University of the Negev; [email protected]
Does dietary protein limit mass gain in migrating blackcaps refueling at
stopovers?
Both fat and protein are used by birds as fuel during migratory flight, and
need to be restored at stopovers. Mass gain is initially slow but increases
after 2-3 days into the stopover. One explanation for this is the catabolism of
digestive tract tissue (GIT), which causes reduced digestive function and
hence slow body mass gain. We tested the prediction that dietary protein
limits a bird's readiness to leave a stopover because it affects the rate at
which the GIT is rebuilt, and, thereby, the rate of tissue accumulation. We
measured body mass, pectoral muscle size, and body composition (by dual
energy x-ray absorptiometry). Thirty migrating blackcaps (Sylvia atricapilla)
were mist-netted and divided into three equal groups. The birds were
deprived of food for 24 hours to assure stopover behavior. The groups were
then provided semisynthetic diets, that differed only in protein content (i.e.
3%, 5.3% and 10%), and water ad libitum during the 6 day experiment. Mean
daily food intake differed significantly among groups (Holm-Sidak multiple
comparison F(2,172)= 4.103, p=0.018). Body mass changed differently over
time among the groups (-0.13±0.08 g/d, -0.10±0.16 g/d, 0.01±0.26; RM
ANOVA, time*group: F ( 1 2 , 1 6 8 ) =3.08, p<0.0006; for 3, 5.3, and 10%,
respectively) as did pectoral muscle size (RM ANOVA time*group: F (12,
168)=2.11, p<0.05). There were no significant differences in the change of fat
fraction from day 1 to day 7 between the groups (ANOVA F(2,6)=0.38, NS).
Thus, the data suggest protein may be a limiting dietary factor, and that
blackcaps require more protein than that we provided to replace fat used as
fuel during migratory flight.
P3.187 ABATE, M.E.*; GRACEY, A.Y.; MALAVASI, S.; TORRICELLI, P.;
Boston University, Massachusetts, Univ. of Southern California, Los Angeles,
University Ca' Foscari of Venice, Italy, University Ca' Foscari of Venice, Italy;
[email protected]
A comparison of brain gene expression from black goby (Gobius niger)
females and males with alternate mating phenotypes
The black goby (Gobius niger) is a demersal spawning fish with females that
deposit their eggs in a sheltered burrow in shallow marine waters. Territorial
males provide parental care. Males have accessory sperm duct glands that
release sperm trail mucins to enhance sperm longevity. These glands are
less developed in small males that invest energy instead into producing
relatively large testes for their body size. The difference in male reproductive
structure correlates with a difference in male reproductive tactics as small
males utilize a sneaker strategy to enter the nest and steal spawns from the
territorial male. Hence, the black goby provides a good model for
investigating the neurogenetic basis for different mating phenotypes. Mature
females and males were collected from the Venetian Lagoon (Northern
Adriatic Sea, Italy) during the reproductive season. Brain RNA was extracted
from individual fish and hybridized against a cDNA microarray prepared for
the goby Gillichthys mirabilis. A machine learning algorithm was used to
identify sets of genes whose expression was associated with the fish.
Although gene expression profiles were generally similar between mating
phenotypes the algorithm identified a number of genes whose expression
was elevated in sneaker males. The top marker gene for sneaker status was
Mannose-P-dolichol utilization defect 1 (MPDU1), a gene of unknown
function but which may be involved in protein N-glycosylation. These data
reveal that changes in mating behavior are linked to transcriptional
differences in the brain and the resulting candidate genes may have utility in
studies of the regulation and evolution of this trait.
P3.61 ABBOTT, Emily/M*; ROBERTS, Thomas/J; Brown University;
[email protected]
Elastic mechanisms as a determinant of anuran jumping performance:
do toads bounce?
Anuran jumping performance varies widely among species. Biomechanical
studies have proposed that some of the best jumpers use an elastic
mechanism to produce power outputs that exceed available muscle capacity.
Most studies of jump power have focused on good jumpers, and it is unclear
whether species with less spectacular jumping performance also utilize an
elastic mechanism. To better understand the underlying determinants of
jumping performance, we used a force plate to quantify power output and
takeoff time in Osteopilus septentrionalis (Cuban tree frogs), Rana pipiens
(Leopard frogs) and Bufo marinus (Cane toads). Maximal jumps elicited from
a large number of trials were analyzed. O. septentrionalis jumps were both
the fastest and most powerful (takeoff time 0.0680.005 s, peak power
308.755.8 W kg -1 body mass), followed by R. pipiens (0.1120.008 s,
66.619.2 W kg-1), while B. marinus performed the slowest and least powerful
jumps (0.1750.03 s, 14.74.3 W kg -1 ). The power output measured for B.
marinus corresponds to less than 100 W kg-1 hindlimb muscle mass (16%
body mass), well below the power generating capacity of typical Bufo muscle
(>200 W kg -1 ). Evidence for an elastic mechanism in B. marinus is also
absent in the shape of power profiles during jumping. The asymmetric power
profile of O. septentrionalis is indicative of elastic energy storage early in the
jump, while B. marinus symmetrical and relatively shallow power curve may
indicate a jump powered directly by muscle contraction. R. pipiens power
profile is intermediate and may reflect an elastic mechanism less effective
than that of O. septentrionalis. These results suggest that variation in anuran
jumping ability may be explained in part by variation in the effective use of
elastic mechanisms. Supported by NSF grant 642428 to TJR.
P3.129 ABDU, R.W.*; ABATE, M.E.; KAUFMAN, L.; Boston University,
Massachusetts; [email protected]
A test for the influence of offspring behavior on parental care in the
convict cichlid (Archocentrus nigrofasciatus)
Heterospecific predators and kidnapping by conspecific alloparents threaten
the survival of the fry of the convict cichlid (Archocentrus nigrofasciatus).
Parents defend their young by attacking intruders and mouthing their fry to
move them to the nest site. Both adults and fledglings get advance warning
of the risk of predation when they are exposed to olfactory alarm cue
released from the broken skin of conspecifics, and they respond by seeking
refuge and with enhanced group cohesion. It is unknown to what extent the
fry can influence the level of parental care behavior. We periodically removed
fry from their home aquaria and exposed them briefly to either conspecific
skin extract or distilled water, and after placing them in rinse containers,
returned them to their parents. We measured parental care by recording the
parents aggression toward threatening juvenile convicts in a glass container
placed near the nest. We tested for fry homing behavior using a mini-flume
that exposed the fry to separate plumes of home aquarium water and foreign
tank water and recorded how much time the fry spent in each plume for three
minutes. We compare the behavior of the parents in the two treatments and
examine the relationship of parental aggression and homing behavior to
evaluate the influence of offspring behavior on parental care.
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P2.171 ADAMS, Amber L*; LIGON, Day B; LOVERN, Matthew B; Oklahoma
State University, Missouri State University; [email protected]
Reproductive and endocrine responses to breeding density in
laboratory-housed green anole lizards
Previous studies have demonstrated myriad effects of social environment on
reproductive physiology, and often these effects are communicated from
mother to offspring via hormone exposure. A preliminary study in 2007
suggested that female green anoles lay fewer eggs and have higher
corticosterone levels when breeding densities are high. In the present work
we follow up and expand upon these results. Breeding females were housed
in cages with either one male (low density) or one male and three additional
females (high density) to evaluate the effects of breeding density on
reproductive effort and plasma and yolk testosterone (T) and corticosterone
(CORT) concentrations. All animals were maintained under standard
breeding conditions for ten weeks and nest boxes were checked daily for
eggs which were frozen for subsequent yolk steroid analyses. Blood samples
were collected from all lizards at the end of the study. We found that
breeding density had no affect on body condition for either males or females,
although body condition declined overall for males. We also found that,
consistent with last year, although there was no treatment effect on egg
mass, females in low density environments produced significantly more eggs
than females in high density environments. Plasma and yolk T and CORT
levels will be analyzed by radioimmunoassay to determine how males and
females responded hormonally to breeding density and whether females
differed in their yolk steroid content as a result of treatment. Such effects, if
present, would demonstrate environmental effects on reproductive
physiology as well as the opportunity for mothers to communicate
information about the environment to their offspring via hormone exposure.
P3.114 ADAMS, E. D. M*; LEYS, S. P.; University of Alberta;
[email protected]
Skin Deep: Examining transepithelial resistance and epithelial
morphology in sponges.
The phylogenetic position of sponges (Porifera) at the base of the metazoan
tree makes them valuable subjects for studying the evolution of animal body
plans. Unfortunately, past descriptions of features such as epithelial tissues
have been vague in this diverse phylum. Sponges are said to lack true
epithelia because tight junctions and basal lamina are absent. However,
homoscleromorph sponges have a type IV collagen found in basal lamina
and a demosponge was reported to express cell junction molecules such as
MAGI and tetraspanin. Further, the recent genome project of Amphimedon
queenslandica has revealed the presence of most cell junction molecules.
We present evidence of functional sponge epithelia by identifying
morphological and physiological similarities between true epithelia and the
pinacodern of several sponge species. Ultrastructural descriptions are
produced using SEM and TEM preparations of adult and juvenile sponges.
Actin labeling is used to highlight organized epithelial architecture and
identify points of cell-cell contact. Transepithelial resistance (TER)
measurements and the transport of labeled dyes are used to test whether
sponge epithelia are leaky or have the ability to seal off a defined internal
milieu. This research informs theories on the origin of cell-cell junctions and
functional tissue layers within Metazoa.
P2.27 ADDIS, E.A.*; CLARK, A.D.; VASQUEZ, R.; WINGFIELD, J.C.;
University of Washington, Seattle, Universidad de Santiago, Chile, University
of California, Davis; [email protected]
Breeding variation of testosterone in the high latitude Rufous-collared
sparrow, Zonotrichia capensis australis
In vertebrates, testosterone regulates many aspects of reproductive function.
In birds, testosterone is important for sperm production and the development
of some secondary sex characteristics, including activation of sexual
behavior and territorial aggression. The challenge hypothesis addresses
trade-offs between circulating levels of testosterone and male breeding
behavior in birds. Two important postulates of the challenge hypothesis are
(1) testosterone levels are high during periods of social instability and
territory establishment when male-male interactions are common and (2)
testosterone levels decrease during the parental phase of breeding if males
exhibit substantial parental care. Most tests of the challenge hypothesis have
been conducted in northern temperate and arctic birds. Investigations of the
Rufous-collared sparrow (Zonotrichia capensis) in Ecuador and Costa Rica
show no correlation between testosterone and aggressive behavior,
suggesting a decoupling of testosterone and aggression. To further explore
this seeming discrepancy, we tested the challenge hypothesis in a
subspecies of the Rufous-collared sparrow, Z.c.australis, breeding at high
latitude in the southern hemisphere. These results were additionally
compared with our previous exploration of testosterone and aggression in
the Rufous-collared sparrow at mid-latitudes of the southern hemisphere.
P1.155 ALAM, J. L.*; LIEBL, A.L.; MARTIN, L.B.; FOKIDIS, H.B.; University
of South Florida, Arizona State University; [email protected]
Are the immune systems of tropical birds glucocorticoid resistant?
Corticosterone alters immune function, but its effects vary depending on
magnitude and duration, immune response characterized, species studied,
and environmental context. In a previous study, we found that a cutaneous
inflammatory response was not affected by chronically elevated
corticosterone in house sparrows (Passer domesticus) from Panama but
similar corticosterone elevation in birds from New Jersey (USA) reduced the
same immune response. This differential sensitivity to corticosterone,
coupled with a more persistent threat of infection in the Panamanian
population, led to the hypothesis that tropical birds generally may decouple
stress hormones from immune responses to maximize immune defense at all
times. To test this hypothesis, we conducted an experiment on different
tropical (Kenya) and temperate (Arizona) populations of house sparrows.
This time, however, we compared the effects of 30 minutes in a cloth bag on
the capacity of plasma to kill gram-negative bacteria (E. coli) to determine
whether i) other tropical house sparrows are immunologically resistant to
corticosterone; ii) acute (versus chronic) stress differentially affects immune
function depending on latitude; and iii) stress affects other components of
house sparrow immunity. Corticosterone release in response to the stressor
was lower in Kenyan than Arizonan birds, but much less so than in the prior
study. Further, bactericidal capacity of blood was not affected by acute stress
in either population, and Arizonan sparrows killed almost all bacteria while
Kenyan sparrows killed almost none. Collectively these results indicate
population differences in immune and endocrine physiology, but not in the
manner predicted. Ongoing studies of these and other sparrow populations
are testing whether patterns are better explained by invasion history than
latitude.
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P3.168 ALLEN, L.C.*; BISSON, I.A.; KUNZ, T.H.; Boston University, Boston,
Princeton University, Princeton; [email protected]
Assessing the Fight-or-Flight Response in the Brazilian Free-tailed Bat
(Tadarida brasiliensis) Using Heart Rate Telemetry
As human populations expand, increased encroachment on natural
landscapes and wildlife habitats is likely. We can expect that organisms able
to adapt or acclimate to human-altered habitats will have a selective
advantage over those unable to do so. One example of a human-altered
landscape condition is the increasing availability and use of highway bridges
by bats. Evidence from previous research, based on measured levels of the
hormone cortisol, suggests that bridge-roosting Brazilian free-tailed bats
(Tadarida brasliensis) experience lower levels of stress and are in better
overall health than their cave-roosting counterparts. This unexpected result
suggests the ability of this species to rapidly acclimate to the potential
stressors we observed at highway bridges. Heart rate telemetry allows direct
and continuous monitoring of an acute response to a stressor and, thus is
ideal for assessing acclimation to repeated stimuli. Heart rate telemetry has
been used on several avian and mammalian species; however, its use on
small, free-ranging bats has not been tested. In July 2008 we assessed the
suitability of heart rate telemetry in the Brazilian free-tailed bat and evaluated
the ability of these bats to rapidly acclimate to environmental stressors in a
large highway bridge roost. To measure heart rate, a small (0.06 g)
custom-made heart rate transmitter was affixed to each bat (~12g) and the
signal was recorded on an MP3 recorder, while the bat was in the roost and
at the onset of nightly emergence. We subjected lactating females (N=4) to
several novel disturbance events (simulated predator) over the course of the
experiment (12-36 hours), as well as noted other potentially disturbing stimuli
(noise and vibration from passing freight trains) that the roosting bats may
experience while roosting in bridge crevices.
P2.70 ALUCK, R. J.*; WARD, A. B.; Adelphi University;
[email protected]
Use of contact points during aquatic and terrestrial locomotion in
polypteriform fishes
Fishes are found in a variety of habitats: from open water to extremely
vegetated areas. Highly elongated fishes are often found in structured
habitats and appear to use these structures to propel themselves while
swimming. Previous studies have shown that limbless lizards and snakes will
use contact points in their environment during locomotion. Research on
terrestrial locomotion in American eels Anguilla rostrata indicated that eels
will move through a field of pegs by pushing against them. In this study, we
tested the effects of structure in the environment during aquatic and
terrestrial locomotion using two species of polypteriform fishes, the highly
elongated Erpetoichthys calabaricus and its close relative, Polypterus
senegalus. This research will determine whether there is a relationship
between body elongation and the use of contact points in the environment
during locomotion. We examined the use of contact points during locomotion
using high-speed video of individuals moving through a field of pegs. We
found that P. senegalus avoids contact points during swimming, but will use
them for forward propulsion during terrestrial locomotion. E. calabaricus,
however, uses contact points for forward propulsion during both aquatic and
terrestrial locomotion. This work is part of a larger study to understand the
evolution of body elongation in fishes in which we assess the effects of
habitat on locomotion. Through this work, we will provide a basis for
understanding the interplay between habitat and body shape in fishes.
P1.117 ALVINE, T*; CROSSLEY II, DA; University of North Dakota;
[email protected]
Chorioallantoic Membrane Vascular Function of the Embryonic
Domestic Chicken (Gallus gallus)
Vascular function and regulation is poorly understood in most fetal/embryonic
vertebrates. Given the complexity of the vascular tree in developing animals,
specifically the presence of the chorioallantoic membrane (CAM) vascular
bed, a thorough investigation of vascular function must be completed. The
CAM vasculature is critical as a gas exchange surface, and thus changes in
vascular resistance will have direct effects on convective gas transport. To
characterize CAM vasculature function, an isolated embryonic chicken CAM
perfusion preparation was used. This model is particularly useful because it
eliminates potential fetal-maternal physiological interactions. Eggs of the
domestic chicken (Gallus gallus) incubated at 38C were selected for study at
days 15 and 19 of the developmental period, days corresponding to maximal
CAM development and the period just prior to lung ventilation, respectively.
On the day of study, the CAM vascular tree was isolated from euthanized
embryos, and the major CAM artery was occlusively catherized. The
preparation was perfused with saline (0.9% NaCl) at rates that mimicked
previously published blood flow rates on these days of development.
Responses of CAM vascular function were studied via pharmacological
manipulation with selective receptor agonists, phenylephrine
(alpha-adrenergic), isoprenaline (beta-adrenergic), and Angiotensin II.
Preliminary data indicate that the embryonic chicken CAM responds to both
beta and alpha-adrenergic receptor stimulation at day 15 and 19. These
data, in combination with molecular in situ hybridization used to localize
receptor mRNA, imply regulation of CAM vascular resistance may be an
important mechanism of altering cardiovascular function in embryonic birds.
P1.110 AMITAI, Oren*; BAUCHINGER, Ulf; MCCUE, Marshall D; PINSHOW,
Berry; Ben-Gurion University of the Negev; [email protected]
The effects of dietary (n-3) and (n-6) oils on basal metabolic rate in
zebra finches.
Dietary fatty acid (FA) profiles play an important role in the composition of
cell membranes. The unsaturation level of cell membranes of birds and
mammals have been shown to be positively correlated with basal metabolic
rate (BMR), but it is unclear whether the unsaturation levels of dietary FAs
are the underlying cause of alterations in metabolic rate. Docosahexaenoic
acid (DHA; 22:5 n-3), produced from dietary linolenic acid (18:3 n-3), is a
highly unsaturated FA found in cell membranes of all vertebrates and is
central to the Hulbert and Else membrane "pacemaker" theory. We therefore
tested the prediction that birds fed a diet enriched with (n-3) FAs have higher
BMR than birds fed a diet enriched with (n-6) FAs. We used 18 Zebra finches
(Taeniopygia guttata, 9 males and 9 females) that were separated by sex
and divided into three groups and fed millet diets supplemented with 8%
safflower (n-6), 8% flaxseed oil (n-3), or no oil for 7-12 days. BMR was
measured by indirect calorimetry on 6 birds at a time (2 from each group) on
days 7, 9 and 12. Mean BMR's for control, (n-3) and (n-6) were 0.29±0.02,
0.26±0.05 and 0.32±0.06 W, respectively, and were not significantly different
(ANOVA, F (2,14) =2.79, P = 0.095). The data in hand do not support the
prediction; in fact they indicate that BMR is lower in (n-3) fed birds. We
conclude that, as has been suggested (D.J. McKenzie, 2000) for sturgeon
and other fish, the BMR response to dietary fat may not be confined to the
cell membrane, but may operate at the whole cell, or organ level as well.
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P3.157 AN, Y*; KRIENGWATANA, B.P.; NEWMAN, A.E.M.;
MACDOUGALL-SHACKLETON, E.A.; MACDOUGALL-SHACKLETON, S.A.;
Univ. Western Ontario, Univ. British Columbia; [email protected]
The relationship between social rank, neophobia and observational
learning in black-capped chickadees (Poecile atricapillus)
Analogous to human personality differences, behavioural syndromes are
consistent patterns in behavioural tendencies across varying situations in
individual animals. Although studies of behavioural syndromes are becoming
more common, few studies connect individual differences in behaviour with
social dominance. Black-capped chickadees flock in the winter, and
dominance hierarchies are critical to their survival and reproduction. We
tested the relation between social rank, neophobia and observational
learning in black-capped chickadees and investigated whether social
dominance is part of a wider behavioural syndrome. We captured twenty-one
chickadees from five different sites in London, Ontario, and measured
individual reactions to novelty and individual differences in ability to learn a
novel foraging task from a conspecific tutor. The latency to approach novel
objects and foods was correlated within individuals which indicates
consistent individual variation in neophobia. Social rank was related to
latency to approach novel objects and food. Lower ranking individuals were
less neophobic, consistent with the characteristic of their dominance
hierarchy in which the dominants control preferential access to resources
and limit the subordinates to forage in riskier environment. Future work will
address whether reduced neophobia and riskier foraging predisposes birds
to becoming subordinate, or vice versa.
P2.112 ANDERSON, K.E.; BLACKBURN, D.G. *; DUNLAP, K.D.; Trinity
College, Hartford CT; [email protected]
Scanning EM of the Placental Membranes in the Viviparous Lizard
Sceloporus jarrovi
In viviparous lizards, placentas sustain the developing embryos inside the
pregnant female through gas exchange and provision of nutrients. We used
scanning EM to reveal the fetal - maternal interface in the spiny lizard
Sceloporus jarrovi (Phrynosomatidae) during the last trimester of gestation.
Two distinct placentas are formed and persist until parturition. The
allantoplacenta consists of the chorioallantois in direct apposition to the
uterine epithelium. SEM reveals that fetal and maternal epithelia at the
placental interface are highly attenuated, but not eroded, and lack surface
specializations. The yolk sac placenta consists of an avascular
omphalopleure (with its isolated yolk mass) in conjunction with the uterus.
The omphalopleure forms elaborate folds, consisting of epithelium and yolk
droplets. These folds protrude into a thick mass of material in the uterine
lumen, formed from degenerating shell membrane, cellular debris, and yolk.
Scanning EM indicates that this material is sequestered into a restricted,
elongated region at the ventral pole, possibly to free up adjacent regions for
placental exchange. The presence of elaborate placental specializations in a
generalized viviparous lizard is unexpected, and underscores the need for
continued explorations of placental diversity in the numerous clades of
viviparous squamates.
P3.179 ANSON, J.Y.*; RICHMOND, R.H.; MARTINEZ, J.A.; Kewalo Marine
Laboratory, Honolulu, HI; [email protected]
Effects of Anthropogenic Stressors on Larval Recruitment in the Reef
Coral Porites hawaiiensis
Anthropogenic stressors affecting nearshore ecosystems are an important
problem throughout the Pacific Islands. Due to the rapid rate of coastal
development in island nations, activities conducted within watersheds have
immediate impacts on adjacent coastal zones. In Hawaii, the coral Porites
hawaiiensis is primarily distributed in shallow water (0-3m) coastal
ecosystems. P. hawaiiensis broods its larvae which are released daily,
year-round. The availability of P. hawaiiensis larvae makes this a good
model organism for analyzing the effects of anthropogenic stressors on coral
recruitment and survival. Recruitment bioassays were performed using
larvae exposed to environmentally relevant concentrations of freshwater,
terrigenous sediments and the anti-microbial soap additive Triclosan, in the
presence of a suitable settlement cue. Our data revealed that these putative
stressors can either prevent or enhance recruitment. This study revealed that
both freshwater and sediment inhibited larval recruitment and Triclosan
caused a slight increase in settlement and metamorphosis. These findings
demonstrated larval sensitivity to water and substratum quality, and the
importance of these parameters to the early life-history stages of corals and
the persistence of coral reefs.
P3.113 ARMFIELD, Brooke A. *; THEWISSEN, J. G. M.; VINYARD,
Christopher J.; NEOUCOM; Rootstown, OH.; [email protected]
Diversity in gene expression patterns during mammalian early tooth
development
Tooth morphology is one of the distinguishing features of mammalian
species, however, little is known about how differences in form along a tooth
row are genetically determined in mammals other than mice. To further
explore the genetic patterning underlying the diversity of tooth morphologies
seen in mammals we looked at early dental development of pigs and
dolphins. These mammals are good models to address this question
because they represent two variations in dental patterns. The domestic pig
(Sus scrofa) dentition maintains several features representative of many
mammals. They have two generations of bunodont teeth and a
primitive-heterodont dental formula (3-1-4-3). In contrast the pan-tropical
spotted dolphin (Stenella attenuata) has a highly derived homodont dentition,
only one generation of teeth and an increased tooth number. It is known that
in mice tooth type is determined early in development by signaling pathways
establishing distinct boundaries for incisors and molars. We looked for
expression patterns of these genes and proteins to establish associations
between molecular events and dental classes across the three different
dentitions. We used immunohistochemistry on dolphin embryos and in situ
hybridization on pig embryos to determine the timing and location of proteins
and genes (BMP4, FGF8, SHH) that influence early tooth type determination
in mice. We found a range of expression patterns among these three
mammal species. For example in dolphins, BMP4 expression was found to
extend much more distally, perhaps contributing to the teeths incisor-like
form. The variability in expression patterns suggest future developmental
studies hold great promise in helping to explain the diversity in dental
patterns across mammals. Supported by NSF.
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P1.19 ARONSEN, G. P.; Yale University; [email protected]
New photographic evidence of the African golden cat (Profelis aurata
Temminck, 1827) at Mainaro, Kibale National Park, Uganda.
The African golden cat (Profelis aurata Temminck, 1827) is one of the least
known felid species. Conflicting data on habitat preferences exist, and scat
analyses suggest it prefers small to medium mammalian species as prey. In
June 2008, multiple camera traps were placed at the site of Mainaro, within
the Kibale National Park of Uganda. A single digital infrared camera trap
recorded three images of a golden cat. The cat, presumably the same
individual, used the same trail over different nights, suggesting the camera
was within the cat's core range. The Mainaro site consists of a mosaic forest
habitat, including mature, disturbed, and colonizing patches. The images
were recorded in the mature forest. Duikers and primates are common at
Mainaro, which are preferred prey items for the golden cat. The occurrence
of the golden cat within this disturbed habitat is a hopeful sign that this
species can persist even in small fragmented forests. Continued
management and monitoring, combined with new research on golden cat
biology and behavior, will maintain and support both the cat population and
the park. This research was supported by the Leakey Foundation, the Iowa
Great Ape Trust, and the Department of Anthropology, Yale University. This
research followed all regulatory and permit requirements of IACUC, Yale
University, and the Ugandan government.
P3.138 ARTITA, Kimberly S.*; POLNASZEK, Timothy; SEARS, Michael W.;
Southern Illinois University; [email protected]
Strategies for optimization in behavioral and ecological research using
evolutionary computation
Classical models in behavioral ecology once were routinely solved using
standard analytical techniques. As models have become more complex and
have begun to include ever increasing levels of biological realism, such
standard optimization techniques are often no longer sufficient
methodologies. With the increased processing power of modern computers
and with more easily-implemented distributed computing techniques,
biologically-inspired computation has become feasible for solving models in
behavioral ecology. Here, we implement and compare the performance of
several biologically inspired techniques--simple genetic algorithm (SGA),
particle swarm optimization (PSO), species conserving genetic algorithm
(SCGA), and multispecies particle swarm optimization (MPSO)--to solve for
optimal phenotypes with regard to probabilities of predator attack and prey
flight in a predator-prey game. Although simple solutions to predict single
phenotypes for predators and prey can be solved with SGA or PSO (with
varying levels of efficiency), more interesting solutions that include additional
alternative phenotypes potentially can be solved using SCGA or MPSO. In
solving for optimal and alternative phenotypes in our predator-prey game,
further simulations that compete each combination of predator and prey
phenotype are required for model interpretation. The resulting solutions are
analogous to those of classical game theory. Potential applications of this
approach span a broad range of behavioral and ecological problems,
especially those problems implemented at the individual level of
organization.
P3.162 AWERMAN, Jessica L.*; ROMERO, L. Michael; Tufts University;
[email protected]
The effect of chronic psychological stress on blood chemistry in
European starlings
Chronic psychological stress in European starlings, Sturnus vulgaris has
been shown to cause a decrease in body weight during the period of stress.
However, after the stress is alleviated body weight not only recovers but
increases beyond the initial value for at least several weeks. We studied the
effect of chronic psychological stress on body weight and ten blood
chemistry parameters in starlings to examine the mechanism controlling the
weight drop and gain. The blood chemistry parameters included albumin
(ALB), aspartate aminotransferase (AST), calcium (CA), creatinine kinase
(CK), glucose (GLU), globulin (GLOB), phosphorus (PHOS), potassium (K+),
sodium (NA+), total protein (TP), and uric acid (UA). To induce chronic stress
we rotated six different stressors (cage tapping, cage rolling, crowding, bag
restraint, human voice, and radio) in a random order for 30 minutes for 4
times per day over 21 days. Mass was measured at least once every three
days during chronic stress. Blood samples were collected three times every
two weeks. As expected the average weight decreased by approximately 5%
during chronic stress. The only parameters that varied over chronic stress
were a decrease in AST and CK. The starlings were then monitored during a
recovery phase of 60 days. In which mass was measured every week and
blood samples were taken three times in the first 21 days. During this period
the average weight remained at a constant 5 10% above the initial weight
prior to the onset of chronic stress. All blood chemistry parameters remained
constant over this period. Our study suggests that there may be a liver or
muscle protein breakdown during chronic stress; however the sustained
increase in weight following chronic stress cannot be explained using the
blood chemistry parameters we measured.
P1.118 AXTMAN, L.M.*; CHAO, E.; HJELMFELT, S.H.; STRATTON, M.S.;
IMAN, J.D.; COVI, J.A.; MYKLES, D.L.; Colorado State Univ., Fort Collins;
[email protected]
Cloning of a cDNA encoding a myostatin-like factor from lobster
skeletal muscle
Claw muscles of decapod crustaceans undergo a premolt atrophy, controlled
by molting hormones (ecdysteroids), to enable withdrawal of the claws at
ecdysis. Myostatin-like factors (Mstn), a negative regulator of muscle growth
in mammals, is expressed in scallop, insect, and crustacean muscles, which
suggests it also plays a role in controlling muscle size in invertebrates. The
American lobster, Homarus americanus, is being used to study the effects of
claw size and fiber composition on Mstn-mediated signaling. The larger
crusher claw contains only slow-twitch (S1) fibers, while the smaller cutter
claw contains fast, S1, and slow-tonic (S2) fibers. We have sequenced a
cDNA that encodes Mstn using RT-PCR and RACE-PCR. The conserved
RXXR cleavage site was present, indicating the presence of a mature
peptide and its N-terminal inhibitory propeptide domain. The nucleotide
percent identity for lobster Mstn versus land crab Mstn was approximately
79%, while the amino acid percent identity was approximately 90%. We are
quantifying the tissue- and fiber-type-specific expression of Mstn using
end-point and quantitative RT-PCR. The results will be related to the control
of muscle size by steroid hormones. Supported by NSF (IBN-0618203).
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P1.119 BADER, BD*; COVI, JA; CHANG, ES; MYKLES, DL; Colorado State
Univ., Fort Collins, UC Davis Bodega Marine Lab, Bodega Bay;
[email protected]
Molting Down-Regulates Myostatin Expression in the Land Crab,
Gecarcinus lateralis: Implications for the Regulation of Claw Muscle
Atrophy
Molting is the periodic shedding of the exoskeleton required for organismal
growth in arthropods. Ecdysteroid hormones initiate cellular processes
necessary for successful exuviation. One process is a programmed atrophy
of the claw muscle, in which the mass is reduced 2-3-fold. This allows the
claws to be pulled through the small joints of the appendage at molt. How
ecdysteroids induce claw muscle atrophy is poorly understood. Myostatin
(Mstn), a member of the TGF beta family of growth factors, is a negative
regulator of muscle growth in mammals and birds. Our hypothesis is that
ecdysteroids increase the expression and/or activation of Mstn signaling,
leading to the expression of genes required for the degradation of myofibrillar
proteins. Real-time RT- PCR was used to quantify the expression of Mstn in
claw and thoracic muscles during the molting cycle. Molting was induced by
multiple limb autotomy. Mstn mRNA levels decreased during premolt and
remained low at 2 and 10 days postmolt in both muscles. The reduced Mstn
expression was associated with an accelerated protein turnover, which may
facilitate changes in myofilament packing as fibers atrophy. Supported by
NSF (IBN-0618203) and scholarships to B.D.B from the Arnold and Mabel
Beckman Foundation and the College of Natural Sciences Undergraduate
Research Institute.
P3.14 BAGWE, R; SOKOLOVA, IM*; University of North Carolina, Charlotte,
University of North Craolina,Charlote; [email protected]
Effect of cadmium exposure on critical temperatures and energy
metabolism of the eastern oysters Crassostrea virginica
Marine intertidal molluscs are exposed to multiple stressors (including
temperature and pollution) in estuaries, which can strongly affect their
physiology. According to the concept of critical temperatures (Poertner,
2002), temperature tolerance in aquatic ectotherms is limited by the
reduction of aerobic scope at sub- and supra-optimal temperatures until it
completely disappears at the critical temperatures (Tc) and transition to
partial anaerobiosis occurs. We determined the onset of anaerobic
metabolism and changes in cellular energy budget in eastern oysters
Crassostrea virginica during acute temperature rise (20C-36C) in order to
determine the Tc and reveal whether exposure to cadmium ( 50 ug L-1 for 30
days) affects Tc. Our data show that as temperature increases, oysters
switch to an anaerobic mode of metabolism as indicated by accumulation of
anaerobic end products and insufficiency of cellular energy. In control
oysters, L-alanine, acetate and succinate significantly rose above the control
levels and ATP concentrations declined at 24C indicating that this is close to
Tc for this population. At higher temperatures, anaerobic end products
continued to accumulate but ATP levels returned to the control indicating that
oysters were capable of at least short-term regulation of cellular energy
balance in the studied temperature range. Cd-exposed oysters demonstrated
significantly lower accumulation of anaerobic end products compared to their
control counterparts at all temperatures. Given that elevated temperatures
lead to hypoxemia in Cd-exposed oysters (Lannig et al., 2008), these data
suggest that cadmium exposure inhibits anaerobic pathways in oysters and
indicates that accumulation of anaerobic end products is not a good index of
Tc in Cd-exposed oysters.
P2.74 BAILEY, IB*; GREEN, MH; HALE, ME; Univ. of Chicago;
[email protected]
Diversity in startle behavior of larval zebrafish
Startle behaviors are important models for understanding simple circuits and
how they generate movement. The major startle of fishes is the C-start,
characterized by a C-shaped body bend during the initial rapid turn (stage 1).
Recently, in esocid fishes, S-start startles, which have a caudal body bend to
the opposite side of the body from the major rostral bend, have been shown
to involve a different pattern of motor control from the C-start. We examine
whether there is variation in the use of caudal bending in zebrafish, a species
believed to perform only C-start behaviors. We recorded video (1000 Hz) of
the startle behavior in five-day-old larval zebrafish. In other species studied,
head stimulation tended to elicit C-starts whereas tail stimulation resulted in
S-starts, so we used both stimuli to generate a range of behaviors. As in
previous study, head stimuli produced greater head angles and durations
than tail stimuli. At both two and four ms after initiation, peak rostral
curvature did not differ between stimulus types, but peak curvature was more
caudal when generated with tail stimuli. Caudal bending was generally to the
opposite side of the body from the rostral bend but was significantly greater
and more rostral in response to tail stimulation. The ranges of caudal
bending to head and tail stimuli overlapped significantly, suggesting either
there is a continuum of responses rather than discrete S-start and C-start
bending patterns or that fish use both bending patterns in response to each
stimulus type. These explanations will need to be tested with
neurophysiological recordings. This investigation indicates more variability
than previously believed in startles typically thought of as C-starts. Supported
by NSF grant IBN0238464 to MEH.
P1.26 BALDINGER, A.J.*; CHUPASKO, J.M.; FORD, L.S.; HANKEN, J.;
HARTEL, K.E.; ROSADO, J.; TRIMBLE, J.; Museum of Comparative
Zoology, Harvard University; [email protected]
Recent and Ongoing Collections Facility Renovations at the Museum of
Comparative Zoology (Harvard University)
Harvards Museum of Comparative Zoology (MCZ) houses some of the most
historically significant and biologically diverse natural-history collections in
the world. Extensive renovations that facilitate collections storage,
collections-based research and teaching have been underway for the last
several years and continue today. Major collection-room renovations have
taken place in many MCZ departments including herpetology, ichthyology,
malacology, mammalogy and ornithology. Funded by both the MCZ and the
U.S. National Science Foundation, these renovations include the installation
of new storage-efficient collections cabinetry and shelving, which provide
much-needed collections-room expansion space, easier specimen
retrievability and enhanced security for the specimens. Separate electronic
databasing and digital-imaging initiatives complement renovations of the
physical space and enhance collections access and utility.
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P2.89 BANET, Amanda I*; SVENDSEN, Jon C.; ENG, Kevin J.; University of
California, Riverside, University of Copenhagen, Denmark;
[email protected]
Linking reproduction, swimming performance, and habitat use in the
Trinidadian Guppy, Poecilia reticulata
Lab studies have shown that pregnancy reduces locomotor ability, increases
predation risk, and may translate into a reduction in fitness. Understanding
costs of pregnancy on locomotion is thus important in understanding the
evolution of reproductive mode and associated life history traits. We
investigate the link between reproduction, locomotion, and habitat use using
Trinidadian Guppy (Poecilia reticulata) populations that exist in either high or
low predation regimes. Female guppies were collected from two high and
two low predation streams. Presence of predators and small-scale variation
in water flow velocity in the capture localities were recorded. We predicted
that pregnant females, particularly those at the more costly later stages of
pregnancy, preferentially use regions of the habitat with the lowest water
velocity and least number of predators. We also predicted that females with a
higher reproductive allocation would have an inhibited escape response and
a higher tailbeat frequency and amplitude when swimming a fixed speed. To
verify that females collected in different sections of the drainages do exhibit
differences in locomotory performance, fish were transported to a nearby lab
where escape response and tailbeat frequency and amplitude were
measured. Immediately following performance trials, females were sacrificed
and preserved for dissection to garner reproductive data. This study
connects previous studies that have examined either performance or
behavior by linking an individual's behavior in a natural setting to swimming
performance. Results will be discussed.
P3.87 BASTON, J.I.*; CHEDIACK, J.G.; CID, F.D.; KARASOV, W.H.;
CAVIEDES-VIDAL, E.; Univ. Nac. San Luis, San Luis, Argentina, Univ. Nac.
San Luis, IMIBIO-SL, San Luis, Argentina, Univ. of Wisconsin, Madison;
[email protected]
Daily expression modulation of SGLT1 in rat jejunum during ontogeny.
SGLT1, the small intestine apical membrane protein responsible for active
glucose absorption, exhibits a daily pattern of activity and protein and mRNA
expression in adult rats. The activity and expression of SGLT1 is higher
during dark periods when the rats are active and feeding than during light
periods when they rest. However, rats during postnatal growth feed
throughout the day and they have increasing nutrient requirements. Thus, we
characterized the daily expression modulation of SGLT1 protein in rat
jejunum at different ages. Using western blots (WB) we semi-quantified
SGLT1 relative to alpha-actin in jejunal homogenates collected at 3:00h,
9:00h, 15:00h and 21:00h from 14d, 21d, 28d and 90d old Sprague-Dawley
rats (ad-libitum water and food; light on schedule: 6h-18h). Immuno-reactive
bands (with MW compatible with different degrees of glycosylation of the
SGLT1 monomer, and the tetramer) for each jejunum sample were summed
and normalized to alpha-actin for analyses. SGLT1 expression pattern
between ages was: 14d <21d=28d, and tended to decrease at 90d. Within
ages, only 90d rats exhibited a clear daily expression rhythm. SGLT1 was
lowest at 9:00h and then rose to reach a peak at 21:00 [statistical differences
(p <0.05): 9:00h < 15:00h = 21:00h = 3:00h]. In summary, SGLT1 protein
expression increases with age reaching maxima during weaning and
post-weaning periods. A daily pattern of expression was apparent only in
young adult rats (90d old). This pattern matches previous observation of a
continuous feeding during the day to supply nutrients to cope with the high
energy requirements of growth. Supported by PICT2004 25561, CyT-UNSL
22Q751 to ECV, NSF IOS0615678 to WHK.
P3.63 BAUMGARTNER, R.E.; WUNDERLICH, R.E.*; SCHMITT, D.; Duke
University, Durham, NC, James Madison University, Harrisonburg, VA;
[email protected]
Collisional mechanics during sifaka bipedalism
Minimization of the energetic cost of locomotion may be an influential
selective factor for mammalian gait choice and kinematics. One significant
cost during terrestrial locomotion is the work limb muscles must do to redirect
the center of mass (COM) from generally downward to generally upward.
Ruina et al (2005) have detailed a model in which redirection of the COM is
described as a collision whose energetic costs during locomotion can be
reduced by minimizing the number of collisions, sequencing multiple limb
contacts during a collision, or simulating an elastic collision in which the
incoming and outgoing velocity vectors create the same angle relative to the
substrate reaction resultant. In order to test the hypothesis that animals will
choose gait patterns that minimize collisional energy loss, we examined the
unusual bipedal galloping gait used by sifakas. Two adult sifaka were
videotaped at 250 Hz during bipedal locomotion across a long force platform.
Collisions per stride, limb contacts per collision, and pseudo-elasticity of
collisions were examined. The latter was calculated as the angle of the COM
velocity to the substrate reaction resultant before and after the redirection of
the COM. Our results support the hypothesis that the bipedal galloping gaits
of sifaka minimize collisional energy loss by: 1) reducing the number of
collisions that occur during each stride to one (walking and running humans
have two), 2)sequencing two limb impacts per collision, theoretically reducing
energy loss by half; and 3)exhibiting pseudo-elastic collisions that minimize
the energy loss of redirecting the COM. These results support the suggestion
that the reduction of collisional energy loss is an important consideration in
gait selection during terrestrial locomotion.
P2.151 BEDORE, C.N.*; KAJIURA, S.M.; Florida Atlantic University;
[email protected]
Sensitivity and morphology of the cownose ray electrosensory system
The electroreceptors of elasmobranch fishes demonstrate the greatest
sensitivity of any known vertebrate electrosensory system. The
electroreceptors are spatially distributed to a greater or lesser extent
according to the variety of head morphologies in this diverse group. Among
the elasmobranchs, the cownose ray, Rhinoptera bonasus, is unique in its
possession of a bilobed head morphology with paired extensible cephalic
lobes on the ventral surface of the head. These cephalic lobes are extended
to closely contact the substratum as the ray searches for benthic prey, This
may facilitate prey detection by placing the electroreceptors closer to the
source of the prey electric fields during foraging. We tested this hypothesis
by quantifying the electrosensory pore distribution of R. bonasus in
conjunction with its sensitivity to prey-simulating electric stimuli. Results were
compared to a more conventionally shaped ray, the Atlantic stingray,
Dasyatis sabina. Rhinoptera bonasus has an average of 786 electrosensory
pores on the combined dorsal and ventral surfaces, with a high proportion of
these pores (40.5%) occurring on the anterior ventral surface; a distribution
much like that of D. sabina. Rhinoptera bonasus demonstrated a detection
sensitivity of 10.4 nV/cm +/- 2.8SE to simulated bioelectric fields, also similar
to reported values for D. sabina. The similarity in pore distribution and
sensitivity, despite the differences in head morphology, reflect the
phylogenetic stability of the electrosensory system, an important sensory
modality. Unlike the benthically associated D. sabina, R. bonasus is more
benthopelagic and may have evolved its unique, extensible, cephalic lobes to
enhance benthic prey detection even while the body remains higher in the
water column.
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P3.1 BEERS, J. M.*; SIDELL, B. D.; University of Maine, Orono;
[email protected]
Nitric Oxide Synthase Activity Correlates with Hemoglobin Content in
Antarctic Notothenioid Fishes
Antarctic icefishes are the only known adult vertebrates to lack the circulating
oxygen-binding protein, hemoglobin (Hb). In addition to carrying oxygen, Hb
is the primary reactant in degradation of the bioactive molecule, nitric oxide
(NO). We thus expect NO to be degraded at a slower rate in Hb-lacking
icefish than in Hb-expressing notothenioids, leading to higher steady-state
levels of NO in the former group. Data from our laboratory support this
prediction. Steady-state concentration of NO, however, reflects a balance
between rates of synthesis and degradation. To evaluate the role of NO
synthesis, we measured catalytic activity of the enzyme responsible for NO
production, nitric oxide synthase (NOS). A 14C-radiochemical assay was
used to determine NOS activity in different tissues of both white- and
red-blooded notothenioids. In brain tissue, NOS activity (pmol min-1 g wet
wt.-1) is greatest in Hb-expressing Notothenia coriiceps (160 11) and lowest
in Hb-lacking Chaenocephalus aceratus (96 10). Red-blooded
Parachaenichthyes charcoti, with Hb levels lower than N. coriiceps, displays
NOS activity intermediate to that of N. coriiceps and C. aceratus (116 7).
Total NOS activity in cardiac tissue is significantly lower than in brain tissue,
but shows the same trend between white- and red-blooded species, with
greatest activity seen in those species expressing Hb (C. aceratus 0.50 0.17;
N. coriiceps 2.93 1.36). Our results suggest that NOS activity in icefishes is
downregulated in response to high levels of NO. Therefore, Hb-lacking
notothenioids may decrease NO production to compensate for slow
degradation of this signaling molecule. We currently are examining
tissue-specific distribution of NOS isoforms in these animals. Supported by
NSF grants ANT 04-37887 and 07-39637.
P2.96B BELL, T.M.*; WARES, J.P.; University of Georgia; [email protected]
Genetic diversity and feeding preferences in the North Atlantic marine
isopod, Idotea balthica
Organisms experience abiotic and biotic factors that vary in time and space
as well as in presence and intensity, even over short distances.
Spatio-temporal environmental heterogeneity that occurs throughout a
species range can result in different selective pressures between
populations, whereby alleles favored in one region of a species range may
be disadvantageous in other regions. Thus, variation in natural selection can
lead to local adaptation and maintenance of genetic and phenotypic diversity
within a species. The marine herbivorous isopod species, Idotea balthica, is
distributed throughout the North Atlantic and exhibits deep population genetic
divergence among populations along the northeastern coast of North
America at the mitochondrial cytochrome oxidase 1 (mtcoI) gene and in
AFLP markers. The diversity of intertidal marine macroalgae changes quite
dramatically along this coastline in a pattern that is similar to the population
genetic patterning found in I. balthica. Feeding preference and food choice
assays were conducted with I. balthica using eight different algal species in
order to determine if genetically distinct lineages have specialized on the
macroalgal species available to the local populations. Individuals were taken
from natural populations and the stomach content was analyzed using
universal algal molecular markers in order to determine the accuracy of
laboratory feeding assays and the algal species diversity consumed by
populations.
P1.54 BEN-ADERET, N.J.*; DEAN, M.N.; Bar-Ilan University, University of
California, Irvine; [email protected]
Ontogeny of morphology and feeding kinematics in Lingcod (Ophiodon
elongatus)
Habitat shifts often require alterations or flexibility in feeding behavior and/or
morphology. These changes may be necessary to adjust to a different prey
base and are particularly vital for habitat changes during early ontogeny,
where the energy demands of rapid growth put a premium on capture
performance exceeding the escape performance of prey. In this study, we
used high-speed videography to examine ontogenetic changes in
morphology and feeding kinematics across an age-series of lingcod
(Ophiodon elongatus), a dominant, temperate Pacific predator that shifts
from soft-bottom inshore to rocky-reef habitats during the 1st year of its life.
As lingcod age, they feed on proportionately larger prey items; although we
predicted older lingcod would exhibit morphological and behavioral shifts
toward relatively larger feeding structures, maximum gape and hyoid
depression scaled with strong isometry and cranial length decreased relative
to body length with age. There was no clear ontogenetic pattern in the
employed feeding mode, as quantified by the Ram-Suction index: at all sizes,
lingcod exhibit both suction- (min. RSI = 0.05) and strongly ram-based (max.
RSI = 0.693) feeding events. However, larger lingcod are proportionately
faster in completing feeding movements and, when initial strike distance is
scaled to predator body length, begin their strikes relatively closer to the prey
item. These data provide a functional morphological context for a
commercially important rocky reef predator and suggest that lingcod can
remain successful predators across a habitat and prey shift through changes
in behavior, not morphology or feeding mode.
P3.130 BERESIC-PERRINS, R. K.*; SHUSTER, S. M.; Northern Arizona
University; [email protected]
Parental Care in Leeches: Brood Size, Gestation Duration, Juvenile
Survival, and Parent/Offspring Interactions in Two Arizona Populations
of Helobdella stagnalis (Hirudinea: Glossiphoniidae).
Helobdella stagnalis is a common glossiphoniid leech exhibiting postzygotic
parental care. Hermaphrodic adults carry their broods ventrally for up to two
weeks before juveniles become independent. When brooding, the parent
ventilates young, and hunts for and presents food to growing juveniles. We
collected adult H. stagnalis bearing cocoons from two distinct habitats;
Montezuma Well (MW), AZ and the Rio de Flag (RDF), Flagstaff, AZ. In
Montezuma Well, arsenic and dissolved CO 2 levels are unusually high,
whereas the Rio de Flag contains grey water from the outflow of the Rio de
Flag Waste Water Facility. We compared brood size, the time required for all
juveniles to detach from parents, and juvenile survivorship among leeches
collected from each site. We also investigated whether detached juveniles
will reattach to parents, and whether such juveniles discriminate between
parents and non-parents when reattaching. We found significant differences
in the average brood size (mean95%CI; MW: 2.80.18, N=19; RDF: 15.10.73,
N=22) and juvenile survivorship (mean95%CI; MW: 13.61.18, N=19; RDF:
57.41.94, N=22) between the two populations; there was no difference in the
time required for all juveniles to detach from the parent. The average brood
size of the leeches at Rio de Flag was similar to other populations around the
world whereas average brood size of the Montezuma Well leeches was well
below this average. To date, the results of the parent/offspring experiment
has shown that the juveniles both populations fail to recognize their parents;
they reattach to any passing adult. Our results indicate that H. stagnalis is
highly tractable in the laboratory, and suggest that distinct trade-offs between
fecundity and care may exist within these populations.
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P2.30 BERGEON BURNS, C.M.*; CAIN, K.E.; KETTERSON, E.D.; Center
for the Integrative Study of Animal Behavior, Indiana University,
Bloomington; [email protected]
Phenotypic integration of testosterone-mediated characters across
distinct subspecies of the Dark-eyed Junco
Male dark-eyed juncos (Junco hyemalis) vary in how much they elevate
testosterone (T) in response to a standardized injection of gonadotropin
releasing hormone (GnRH). Responses to a GnRH challenge are repeatable
across individuals and co-vary with significant phenotypic characters,
including aggression and ornamentation (tail white). However, the question
of whether such patterns are preserved as species diverge remains
unanswered, as few studies have attempted direct comparisons of
hormone-phenotype relationships across populations. If these relationships
are highly integrated, we would expect similar patterns, but if hormone signal
and hormone response evolve independently we might not. The
white-winged junco (J. hyemalis aikeni) is a subspecies of dark-eyed junco
endemic to the Black Hills of South Dakota. It is the largest of 15 named
junco subspecies and the most highly ornamented. We asked whether
hormone-phenotype relationships already identified within a population of
Carolina junco (J. hyemalis carolinensis residing in Virginia) would generalize
to the white-winged junco, and whether the responses would be stronger in
this more ornamented population. During 2007 and 2008, we captured,
measured, and administered GnRH challenges to breeding male
white-winged juncos. We found similar within-population relationships
between T and phenotype, suggesting generalizability. We also found
greater elevation of T in response to GnRH in the white-winged junco as we
had predicted. Our findings suggest stable hormone-phenotype relationships
across populations maintained at least in part by variation in hormone signal,
thus supporting the hypothesis of phenotypic integration.
P1.132 BERGMAN, D.A.*; SAMMETA, N.; MCCLINTOCK, T.S.; Grand
Valley State University, University of Kentucky; [email protected]
Growth Factors and Receptors in the Olfactory Epithelium
The olfactory epithelium (OE) is a dynamic cellular environment where cell
death, proliferation, and neural differentiation are continuous. These
dynamics are coordinated by signaling events, some of which are known
(e.g., Wu et al. 2003, Neuron 37:197). Our microarray data predicts
expression of 47 growth factors and 30 growth factor receptors in the
olfactory epithelium. The data also predict whether they are expressed in
olfactory sensory neurons (OSNs) or in other cells in the olfactory epithelium.
We have used in situ hybridization to test these predictions. OSNs express
growth factor receptors Acvr1, Arvcf, Bmpr1a, Fzd3, Igf2r, Pdgfrb, Pdgfr1,
and Tgfbr1, and growth factors Ecgf, Fgf9, Fgf12, and Pdgfa. Basal cells
expressed growth factor receptors Fzd3 and Tgfbr1, and growth factors Hdgf
and Pdgfa. These data agree with evidence of local signaling in the olfactory
epithelium by PDGF and TGF-b family signals. They also predict roles for
Wnt, Ecgf, and Hdgf signaling in the olfactory epithelium, or in the case of
signals expressed by OSNs, the possibility of signaling to cells outside the
olfactory epithelium such as olfactory ensheathing cells or cells in the
olfactory bulb.
P1.66 BERNAL, Diego*; SYME, Douglas; MCGILLIVRAY, David; DONLEY,
Jeanine; SEPULVEDA, Chugey; Univ. Mass. Dartmouth, Univ. Calgary,
MiraCosta College, Pfleger Institute of Environmental Research;
[email protected]
The effect of temperature on the muscle contractile properties in the
common thresher shark
This project measured the contractile properties of the aerobic red (RM) and
anaerobic white myotomal (WM) muscle in the common thresher shark
(Alopias vulpinus) captured in the Southern California Bight. Muscle twitch
kinetics were measured in situ with a portable stimulator and force
transducer and showed no significant longitudinal variation in twitch
response of superficial WM. Laboratory preparations of WM fibers exhibited
isometric twitches at temperatures as low as 8C, while RM twitches
drastically slowed (time to peak force in excess of 1.5s) at this temperature.
The in vitro work loop technique was used to quantify temperature
dependent work and power output in isolated muscle preparations. In WM
the cycle frequency yielding maximum power ranged from 1.0Hz at 8C to
1.5Hz at 24C, and positive power was maintained up to 2.5Hz at 8C and
4.0Hz at 24C. In the RM positive power output was restricted to relatively
lower frequencies, less than 1.5Hz at 24C, less than 1.0Hz at 16C, and
0.5Hz at 8C. These results show that while thresher shark WM can power
fast swimming across a wide range of temperatures, the RM is more limited
in its thermal tolerance. However, the overall thermal effect on RM power in
the common thresher appears to not be as pronounced as that documented
in other regionally endothermic sharks.
P2.188 BERNER, N.J.*; BULLOCK, J.R.; Sewanee:University of the South,
Sewanee, TN; [email protected]
Fatty acid composition of membranes and storage fat in the Eastern
red spotted newt (Notophthalmus viridescens viridescens)
Eastern red spotted newts acclimate enzyme activity and metabolic rate
seasonally, in the laboratory and in the field. Winter and cold-acclimated
newts have higher skeletal muscle cytochrome c oxidase (CCO) and citrate
synthase activity and higher standard metabolic rates than summer and
warm-acclimated newts. Membrane fatty acid (FA) composition can affect
membrane-bound proteins such as CCO, and metabolic rate. We
investigated the FA composition of muscle membranes to determine if
changes in CCO activity could be due to changes in membrane FA
composition. We are also interested in the regulation of membrane FA
composition and remodeling, so we also determined the FA composition of
storage fats (triglycerides and fat bodies). Finally, as diet also impacts FA
composition, we determined the FA contents of the newt diets. Newts were
collected in the field in January and July 2008, euthanized, dissected,
stomach contents collected and samples stored at -80C. Laboratory newts
were purchased in October 2008 from Amphibians of North America, and
acclimated in the laboratory for 12 weeks (cold-acclimated 8C, 10:14;
warm-acclimated 26C, 14:10) and fed mealworms (Tenebrio, sp). At the end
of 12 weeks, newts were euthanized, dissected and stored at -80C. Lipids
were extracted in methanol:chloroform (2:1 v/v). Phospholipids and
triglycerides were separated on silica cartridges. These lipids were
methylated using acetyl chloride in methanol:toluene (4:1 v/v). The FA
methyl esters were separated by gas chromatography on a Varian 3900 with
a fused silica column (100 m x 0.25 mm) with select FAME coating tailor
made. Individual FAs were identified by comparing each peaks retention time
with that of external standards, and FA content was expressed as mol% of
total FA.
e200
P2.109 BERTRAM, Douglas F.; PHILLIPS, Nicole E.; STRATHMANN,
Richard R.*; Environment Canada, Victoria Univ. Wellington, Univ. of
Washington; [email protected]
Doubling Egg Volume to Test for Reversible Evolution of Larval Form
and Effects of Eggs Size on Heterochrony
Doubling volume of the small eggs of the purple sea urchin
Strongylocentrotus purpuratus by egg fusion produced larvae more similar in
form to those from normal large eggs of the green sea urchin
Strongylocentrotus droebachiensis. This result mirrors previous experiments
in which larvae from half embryos of green urchins were more similar to
normal larvae of purple urchins. Thus effects of egg size on larval form are
similar against either species genetic background and are evolutionarily
reversible. Development of the juvenile rudiment was not accelerated relative
to the larval body by experimentally doubling the volume of eggs of purple
urchins. In larvae from normal-size eggs, development of both larval body
and rudiment were accelerated in green urchins (with large eggs) relative to
development in purple urchins (with small eggs), but with greater
acceleration of the larval body, so that the rudiment of larval green urchins
was initiated at a later stage, even though at an earlier age. Both species
exhibited similar plasticity in timing of rudiment development in response to
food supplies. Although heterochronic plasticity in development of the larval
body and juvenile rudiment in response to food may be a basis for similar
heterochronic changes in the evolution of non-feeding larvae, experimental
and evolutionary changes in egg volume did not directly accelerate rudiment
development of these feeding larvae.
P3.68 BERTRAM, J.E.A*; SZARKO, M.J.; PREBEAU-MENEZES, L; Univ. of
Calgary, Calgary; [email protected]
Function and fatigue: Changes over a marathon race in recreational
athletes.
Even compared with many cursorial mammals, fit humans display a
remarkable ability to run long distances at moderately high speeds. This
suggests long distance running may be an adaptive feature of humans.
Although substantial research has been conducted on running mechanics
and physiology, the process of fatigue and the functional response to
extreme endurance is not well understood. As a recognized test of
endurance, the marathon has become a goal of many non-elite, recreational
running enthusiasts. We exploited the opportunity to analyze the changes in
gait of a range of individuals participating in a community marathon race
using a series of instrumented force platforms that could monitor features of
gait pre-race, mid-race (19 km) and near the end of the race (36 km). Not
surprisingly, we found that the most successful runners (lowest finishing
times) were able to maintain running speed for the duration of the race with
very little change in speed or gait. Those with slower race times began the
race at roughly similar pace to the faster runners, but this slowed as the race
progressed, indicating the effects of fatigue. Interestingly, in fatigue speed
decrease results from a decrease in stride length not stride frequency. This is
contrary to most lab studies of fatigue; however, these are generally
conducted using a constant speed protocol (treadmill) in which the subjects
gait options are necessarily constrained. Shorter steps at a given frequency
alter the geometry of the contact with the substrate, which, combined, with
the elastic recovery of the running step, limits the required work performed
by the leg. Well-trained runners show the same step length change with
increase in age over their running career as the younger recreational runners
show with progress over the course of a single race.
P3.181 BEZAULT, E.*; MWAIKO, S.; SEEHAUSEN, O.; EAWAG and
University of Bern, Switzerland, Tanzania Fisheries Research Institute and
EAWAG, Kastanienbaum, Switzerland; [email protected]
Investigating the evolutionary mechanisms in the adaptive radiation of
cichlid fishes of Lake Victoria basin
The Lake Victoria cichlid superflock, comprising the related radiations of
lakes Victoria, Edward, Albert and Kivu, is an example of the most explosive
adaptive radiation, with more than 500 species evolved within the last
15-100,000 years, and the most recent in the East African Great Lakes. The
repetitive occurrence of the same adaptively important traits in unrelated taxa
within and between lakes makes the superflock, and especially the Lake
Victoria flock, an ideal model for studying adaptive radiation in shape,
ecology and behaviour. However its very recent origin is a challenge for
phylogenetic reconstruction because of incomplete lineage sorting and
potential for hybridization. In contrast with the well supported monophyly of
the mtDNA lineage (d-loop & ND2), the nuclear data (AFLP) suggest that the
nuclear genomic diversity of Lake Victoria superflock received contributions
from several unrelated lineages that hybridized when seeding the radiations.
This could explain the segregation of numerous polymorphisms within and
between radiations of the superflock. Furthermore, the shallow levels of
species structure at neutral loci within Lake Victoria cichlids contrasts with
strong differences based on adaptive genetic and phenotypic diversity.
These data raise the possibility that functional traits can be transferred
between species by the interaction of hybridization and selection. This is
investigated by studying a large number of genomic markers (AFLP) to i)
reconstruct a species level majority-genome phylogeny for the superflock
and ii) to detect loci under selection associated with adaptively important
phenotypic traits.
P2.101 BHAT, A.*; MARTINS, E.; Indiana University, Bloomington;
[email protected]
Morphological Divergences among wild populations of zebrafish, Danio
rerio
Divergences in morphology among populations have been studied in several
species of vertebrates and gradients in environmental features are known to
be a major driving force for microevolutionary changes. Body shape
variations among fish species are affected primarily by differences in water
flow regimes, predation pressure and feeding habits. Here we measured
variations in body shape and size among wild populations of zebrafish
(Danio rerio) collected from moving and still water (streams and lakes)
conditions in their natural habitats in northeast India. Geometric
morphometric analyses conducted on male and female individuals from
these populations were used to test predictions that habitat differences,
particularly, in flow regimes between these populations can produce
differences in body morphology. We conducted comparative analyses (using
univariate ANOVA, t-test) of centroid size across lake and stream
populations as well as between sexes. Multivariate analyses (discriminant
function analysis) on partial warps were used to test effects of habitats on
body morphology. One-way ANOVA showed a significant effect of habitat
type on centroid size (F 1 , 2 1 3 =16.4, p<0.01). Lake populations were
significantly larger in centroid size than stream populations (independent
t-test: t214 =4.05, p<0.01). While pooled data for lake and stream populations
did not necessarily show significant differences in body shape, we found
significant differences among some populations. These populations are
subjected to fluctuations in water flow and high rainfall during some seasons
can drive inter-population mixing. This could thus constrain morphological
diversification. Inter-population (spatial) distances might also play an
important role in determining morphological divergences.
e201
P1.96 BIER, R*; TANKERSLEY, R; LOPEZ, P; BRODIE, R; University of
Georgia, Florida Institute of Technology, Scripps Institute of Oceanography,
Mount Holyoke College; [email protected]
Fiddler crab locomotion: Are tide-related rhythms the same in lab and
field studies?
Some behaviors of intertidal organisms are endogenously regulated and
correlate with the cycle of ebbing and flooding tides. For organisms that feed
intertidally, timing their movement to and from feeding areas may be
especially important if they are to take advantage of favorable feeding
conditions. Fiddler crabs ( Uca ) feed on exposed substrates at low tide and
are a model organism for biological rhythms research. The purpose of this
study was to determine if drove migration by the fiddler crab Uca pugilator
between feeding and burrow locations under the natural conditions of its
habitat was correlated with circadian or tidal rhythms. For 15 days in July
2005, during sunlight hours, we recorded the number, direction (toward
feeding area = outbound or away from feeding area = inbound), and sex of
crabs at an observation point between the burrow and feeding areas on a
mud flat. Additionally, we collected 20 U. pugilator from the field site and
recorded their locomotory movement for 7 days under controlled conditions
using an infra-red actograph system. A general linear model showed that the
time of high tide corresponded with both outbound and inbound movement in
the field, but that the peak time of movement in the field did not correspond
with peak frequency of movement under controlled conditions. There was no
significant sex difference in the timing of this movement in the field, though
under controlled conditions females' peak activity occurred 1 hour prior to
males'. Thus, peak inbound or outbound movement for a U. pugilator drove
at the field site can be used to predict the time at which a flooding or ebbing
tide may occur there. Moreover, this study highlights the importance of
observing activity in the field, as the results under controlled conditions did
not reveal the functional locomotory pattern.
P3.19 BIRD, S.E.*; ZAPUT, E.P.; MUSTA, E.J.; BENENATI, E; BENENATI,
J; Los Rios College, Salt River Pima-Maricopa Community High School,
Flagstaff High School, Northern Arizona University, Department of Biological
Sciences; [email protected]
Developing a riparian zone measurement protocol for perennial
streams in North Central Arizona
Riparian areas support more productive and diverse vegetation communities
and serve more ecological functions than their terrestrial upland
counterparts. These areas provide important links between terrestrial upland
and aquatic ecosystems. Our study evaluated riparian parameters at two
streams, Oak Creek and Pine Creek. Oak Creek is a third-order multi-use
stream that originates on the Colorado Plateau and flows into the Verde
River near Clarkdale. Pine Creek is a first-order stream that flows from the
edge of the Mogollon Rim to the town of Pine, Arizona. The following
parameters were measured at both sites: stream depth, flow velocity, stream
width, floodplain width, channel gradient, first and last riparian tree, first pine
tree, tree identification, tree distance from stream edge, tree height, and
upland characteristics. Data was analyzed using a MANOVA test that
included predictor variables of site and last riparian tree. Oak Creek and Pine
Creek riparian habitats were significantly different for the parameters
measured (MANOVA-Wilks Lambda, df=5,202; f=82, p<0.001). Maximum
extent of riparian habitat was significantly related to stream depth, stream
width, floodplain and first riparian tree based on a multi-step pair-wise
analysis (R2=0.31; ANOVA df=4,317; f=35, p<0.01). Our data determined
that although Oak Creek and Pine Creek had significantly different riparian
characteristics, these measurements could be used as a predictor for
determining the maximum extent of riparian habitat. With further
development, this protocol could be used as a predictor for determining the
riparian area with minimal effort.
P3.112 BIRD, Nathan C.*; HERNANDEZ, L. Patricia; George Washington
University; [email protected]
Is the Weberian apparatus a key innovation: causal versus permissive
evolutionary factors?
Key innovations are structures, behaviors, or functions intimately linked with
the evolutionary success of one or more groups of organisms. Over the past
several decades, numerous potential key innovations have been proposed to
explain the disparity of species diversity between closely related groups.
Proposed key innovations include such examples as flight, phytophagy in
insects, the labroid pharyngeal jaw apparatus, and floral nectar spurs.
However, key innovations have been plagued with criticisms regarding their
testability and their specific role in the evolutionary process. This confusion is
readily apparent in the numerous competing definitions and tests proposed in
the literature. A large segment of these tests focus on historical testing
(causal factors), requiring at least two independent origins of the innovation.
More recently, functional testing as well as the addition of developmental and
genetic influences (permissive factors) into key innovation testing have
become alternative means to address unique key innovations previously
considered untestable using historical methods. We evaluate the utility of
these competing methods of key innovation testing with respect to the
Weberian apparatus, a hearing adaptation that includes a set of novel
vertebral modifications diagnostic of the Otophysi, a large clade of freshwater
fishes. We test the hypothesis that these hearing modifications are critical to
the success of the clade using modified traditional criteria, as well as using
more recent functional and developmental tests within an ecological context.
We conclude that sufficient support exists for the role of the Weberian
apparatus as a key innovation in the evolutionary history of otophysan fishes.
P1.10 BLUMSTEIN, D.T.; CHMURA, H.E.*; WEY, T.; Univ. of California, Los
Angeles, Swarthmore College; [email protected]
Do parasites and body condition explain variation in anti-predator
vigilance?
Most animals must allocate some time to anti-predator vigilance. While
hundreds of studies have examined antipredator vigilance in birds and
mammals, much variation in vigilance remains unexplained. Prior research in
marmots indicates that anti-predator vigilance is sensitive to environmental
factors such as incline and vegetation height. We examined whether internal
factors might also explain variation in anti-predator vigilance. We studied
yellow-bellied marmots (Marmota flaviventris), a large ground squirrel found
in alpine and subalpine areas of Western North America. Adult and yearling
marmots were live-trapped at Rocky Mountain Biological Laboratory (RMBL),
Gunnison County, Colorado, USA during spring and summer months from
2004 to 2008 and sampled for blood, fecal and ectoparasites. Body condition
was measured as the residual of a general linear model with mass as the
dependent variable and age, sex, colony, year and time of season as
independent variables. We quantified vigilance behavior in foraging marmots
during 2 minute focal samples taken during the early morning (06:00-11:00)
and late afternoon (15:00-19:00) from late April to mid-August. We fitted
general linear models to explain variation in three measures of marmot
vigilance. We found that increases in body condition corresponded with
decreases in each measure of marmot vigilance. Marmots infected with
Entamoeba, an intestinal parasite, tended to spend a greater proportion of
time vigilant. By contrast, marmots infected with Eimeria, an intestinal
parasite, or Trypanosoma, a blood parasite, tended to decrease average
vigilance bout duration. Our results suggest that some variation in vigilance
is explained by internal condition and parasites; however, substantial
variation remains unexplained.
e202
P3.134 BOCKOVEN, A.*; AMARELLO, M.; SEARS, M.W.; Southern Illinois
University; [email protected]
Implications of tradeoffs between crypsis and thermoregulation for the
evolution of animal coloration
Patterns of covariation between the coloration of animals and their
environments are some of the most striking examples of adaptation in
nature. For ectotherms, such patterns likely result from a tradeoff between
thermoregulation and crypsis. That is, coloration will influence both the
amount of radiation that is absorbed by an individual from the environment
as well as determine how conspicuous an individual appears in its
environment. An evolutionary tradeoff may when occur when coloration that
is optimal for thermoregulation causes an individual to be more easily
detected by predators. One system that shows striking patterns of color
matching between individuals and their environment is the lizard community
of the Tularosa Basin in New Mexico, USA. Coloration of lizards ranges from
melanistic in the Carrizozo lava field to blanched in the White Sands dune
system. Here, using biophysical models that incorporate morphological and
spectral traits of lizards along with the physical characteristics of the
background environment, we examine the consequences of color matching
on activity and energy budgets of lizards in this system. Further, we conduct
virtual transplants to examine the consequences of patterns of animal
coloration that contrast with their environment. We propose that tradeoffs
between thermoregulation and predation likely have given rise to patterns of
coloration for lizards in the Tularosa Basin.
P1.44 BOLANOS, D. Marcela; LITVAITIS, Marian K.*; University of New
Hampshire; [email protected]
Embryonic muscle development in direct and indirect developing
marine flatworms (Platyhelminthes, Polycladida)
We compared embryonic myogenesis of the direct-developing acotylean
polyclad Melloplana ferruginea with that of Maritigrella crozieri, a cotylean
that develops via a larval stage. Fluorescently-labeled F-actin was visualized
with laser confocal microscopy at different developmental stages.
Developmental stages are reported as percentages of the time from
oviposition to hatching. Development was completed in 7 d for M. crozieri
and 22 d for M. ferruginea. At 30% development in M. crozieri and at 15%
development in M. ferruginea polygonal outlines of epithelial cells were
visible on the surface of the embryo. Random myoblasts appeared in
peripheral areas of the egg at 36% and 22-30% development in M. crozeri
and M. ferruginea, respectively. Because large amounts of yolk accumulated
in the center of developing M. ferruginea, timing of the formation of primary
circular and longitudinal muscle bands was possible only for M. crozieri and
occurred between 37% and 44% development. For both species, an
orthogonal muscle grid was established by 45-50% development. Diagonal
muscles developed in M. ferruginea at 60-71% development. Hence,
juveniles hatch with the basic body-wall musculature of adults. Larvae of M.
crozieri did not hatch with diagonal muscles; these muscles are acquired
post-metamorphosis. Specialized musculature developed in the larval lobes
of M. crozieri. Oral musculature was found to be complex and was
established by 72% development for both species. Our results are
comparable to the muscle differentiation reported for another
indirect-developing polyclad, Imogine mcgrathi and for a direct-developing
species of macrostomid flatworms. Furthermore, they provide additional
support that the orthogonal muscle pattern is a symplesiomorphy of Spiralia.
P2.60 BONIN, J.A.*; HOSSEIN, I.; HAM, K.; OGUNBAKIN, T.; HOPKINS,
B.A.; OSBORN, M.L.; BARNETT, H.A.; MATTHEWS II, K.L.; BUTLER, L.G.;
BRAGULLA, H.H.; HOMBERGER, D.G.; Louisiana St. Univ., Baton Rouge;
[email protected]
The complex morphology of the cat claw as revealed through virtual
dissection by x-ray computed tomography and software-assisted
visualization.
The cat claw is a complex organ consisting of tissues with different physical
and biological properties: Vascularized bone in complex shapes, soft tissues
comprising the vascularized dermis and avascular epidermis, and the
cornified claw sheath with hard-cornified and soft-cornified horn elements.
This structural complexity makes claws difficult to visualize by established
techniques. X-ray computed tomography (CT) and software-assisted
visualization techniques allow a non-destructive visualization of such objects
because of the diversity of their tissues. This technique works best for dense
tissues (bone, hard-cornified tissues). Soft tissues require innovative
preparation techniques (selective maceration, vascular casting). This
technique can be used on non-preserved specimens and leaves them intact
for other imaging techniques. The application of a combination of techniques
on the same object controls for artifacts that are inherent in all biological
preparation techniques. The quality of images produced by x-ray CT is
limited by the resolution of the scanning devices; it can be increased by
using a synchrotron x-ray source. Software-assisted virtual dissection
techniques can section the same object in different planes and can virtually
remove, highlight, or isolate specific tissues.
P3.147 BOOHER, C.M.*; HOOD, W.R.; Auburn University, Alabama;
[email protected]
Calcium intake, bone metabolism and reproductive output of
white-footed mice (Peromyscus leucopus)
The ossification of mammalian fetal and neonatal skeletons requires a
significant amount of calcium transfer from maternal sources via the placenta
during pregnancy and milk during lactation. Many mammals meet elevated
calcium demand at this time by increasing bone resorptive activity, which
mobilizes calcium stored in the skeleton. Consequently, maternal bone
mineral content and density may be reduced to detrimental levels. When
dietary calcium intake is low, females have been shown to rely more heavily
on skeletal stores, resulting in relatively greater reduction of bone. To
address the potential trade-off between maternal skeletal maintenance and
offspring production when calcium availability is low, we provided either a
low-calcium diet or a standard diet to reproducing white-footed mice and
assessed 1. changes in bone mineral density and bone mineral content of
the femur, tibia and lumbar vertebrae using dual-energy x-ray absorptiometry
2. changes in bone resorption activity using bone marker assays and 3.
differences in offspring production relative to calcium intake. Females
consuming the low-calcium diet produced more pups and experienced
greater bone loss than females on the standard diet, suggesting that not only
are resources preferentially allocated to offspring production, but relatively
more is apportioned when calcium availability is low. Our results corroborate
with life history theory regarding short-lived animals that experience
fluctuating resource abundance.
e203
P3.2 BORLEY, K.A.*; SIDELL, B.D.; University of Maine;
[email protected]
Nitric Oxide-mediated Angiogenesis in Antarctic Icefish?
Nitric oxide (NO), produced by nitric oxide synthase, regulates diverse
processes including angiogenesis and mitochondrial biogenesis. NO rapidly
degrades in most vertebrates by reaction with hemoglobin (Hb) and
myoglobin (Mb). Antarctic icefish completely lack Hb. In the absence of Hb,
we hypothesize that NO accumulates to higher steady-state concentration.
This may trigger high cardiac mitochondrial density and dense retinal
vasculature observed in these fish. We measured breakdown products of NO
(NO2- and NO3-) in plasma of Hb and +Hb Antarctic notothenioids. Aggregate
[NO 2 - + NO 3 - ] are higher in plasma of Hb icefish (C. aceratus: 22.75 +/1.15M) than in a red-blooded notothenioid (N. coriiceps: 14.66 +/- 0.67M),
indicating that NO concentrations are higher in white-blooded fish than +Hb
fish. To evaluate whether NO stimulates angiogenesis in white-blooded fish,
we used quantitative PCR (Q-PCR) to measure expression of genes involved
in angiogenesis in Hb and +Hb notothenioids. We found no significant
differences in expression of hypoxia inducible factor-1α (HIF-1α) or vascular
endothelial growth factor (VEGF). These results suggest that, if loss of Hb
stimulates angiogenesis in icefish, the process must occur early in
development and is not upregulated in adults. To further test relationships
among [Hb], [NO] and angiogenesis, we treated red-blooded notothenioids
with phenylhydrazine (PHZ), a potent hemolytic agent. Hematocrit of fish
treated with PHZ for 10 days decreased from ~37% to less than 5% while
[NO 2 - + NO 3 - ] increased concomitantly (N. coriiceps: 14.66 +/- 0.67M, N.
coriiceps + PHZ: 19.60 +/- 1.18M, p=0.01). Expression of PHD2 (prolyl
hydroxylase domain protein-2), HIF-1α and VEGF, known angiogenic
factors, significantly increases in PHZ-treated N. coriiceps. Supported by
NSF grants ANT 04-37887 and 07-39637.
P1.139 BOSWELL, L.C.*; MENZE, M.A.; HAND, S.C.; Louisiana State
University, Baton Rouge; [email protected]
Multiple isoforms of Late Embryogenesis Abundant proteins in Artemia
franciscana embryos.
Late Embryogenesis Abundant (LEA) proteins are highly hydrophilic, low
complexity proteins whose expression has been correlated with desiccation
tolerance in anhydrobiotic organisms. Originally discovered in plants, LEA
proteins have also been identified in bacteria, cyanobacteria, fungi,
nematodes, brine shrimp, and a chironomid insect larva. We have currently
identified and sequenced six LEA genes in embryos of the brine shrimp
Artemia franciscana. The deduced amino acid sequence of one protein
(AfrLEA3m) is predicted to be mitochondrially localized by subcellular
targeting programs. Bioinformatic analysis of these six proteins has shown
each to contain qualities indicative of a group 3 LEA protein including strong
hydrophilicity, and prediction of high alpha-helix content. Two of the Afrlea
genes have been successfully cloned into a bacterial expression system and
one protein isoform has been overexpressed and purified. Furthermore
RT-qPCR has been performed on three of the six AfrLEA mRNAs. This
analysis has revealed the mRNA expression of all three to be several fold
higher in the two embryonic stages of A. franciscana that possess
desiccation tolerance, when compared to the desiccation-intolerant nauplius
larva. Verification of the predicted mitochondrial location of AfrLEA3m has
also been accomplished, which represents the first evidence of a LEA protein
targeted to mitochondria of animals. A nucleotide construct encoding the first
seventy N-terminal amino acids of AfrLEA3m was ligated to the nucleotide
sequence for green fluorescent protein (GFP) and transiently transfected into
human hepatoma cells (HepG2/C3A). As confirmed with confocal imaging,
the expressed fusion protein was imported into mitochondria. [NIH grant 2
RO1 DK046270-14A1]
P2.189 BOYLES, J.G.*; DUNBAR, M.B.; SCHULER, M.S.; STORM, J.J.;
Indiana State Univ., Univ. of Regina, Univ. of South Carolina Upstate;
[email protected]
Determining Metabolized Fuel Source during Arousal from Hibernation
using Stable Isotope Signatures in Breath.
Fat-storing mammals rely mostly on a fixed energy source, white adipose
tissue (WAT), to survive the hibernation period; however, brown adipose
tissue (BAT) and food may lessen use of WAT in specific situations. BAT is
used mainly for thermogenesis during arousal to raise body temperature to
euthermic levels, but methods previously used to estimate the time course of
BAT metabolism have poor temporal resolution and generally require
subjects to be euthanized. Feeding during winter is possible in some
situations, but it is unclear if fat-storing mammals metabolize food
immediately to power euthermy, or if it is converted to WAT for later use. We
conducted two experiments with wild little brown bats (Myotis lucifugus) to
test the efficacy of a relatively new technique, stable isotope analysis of
excurrent breath, in determining the metabolic fuel powering arousals from
hibernation and the subsequent euthermic periods. First, we collected breath
samples from 16 bats as they aroused from hibernation to determine if the
change between BAT and WAT being metabolized for thermogenesis was
detectable in excurrent breath. Second, we fed 48 euthermic bats
mealworms with a known isotopic signature to determine if bats can quickly
metabolize an exogenous energy source during euthermic bouts. The results
of the first experiment suggest the isotopic signatures of WAT and BAT vary
enough to be detectable in excurrent breath. The results of the second
experiment suggest that despite a known atrophy of the digestive system
during hibernation, bats begin metabolizing exogenous fuel sources shortly
after feeding and continue to metabolize them for several hours.
P3.141 BRABY, C.E.; PEARSE, V.B.*; VRIJENHOEK, R.C.; BAIN, B.A.;
Monterey Bay Aquarium Research Institute, Moss Landing, CA, University of
California, Santa Cruz, Southern Utah University, Cedar City;
[email protected]
Pycnogonid-cnidarian interactions in the deep Monterey Submarine
Canyon
Whale carcasses, sunken wood, and cold seeps provide organically enriched
oases in the food-limited deep-sea benthos. At 3 such enriched habitats in
Monterey Bay, California, at a depth of nearly 3,000 m, we observed
pycnogonids (sea spiders) of at least two species, Colossendeis gigas and
C. japonica, feeding on sea anemones commonly found there. Submersible
remotely operated vehicles (ROVs) provided direct observations of feeding,
as well as high definition video and photographic images. We recorded the
presence and abundance of both pycnogonids and anemones over the
course of 12 visits during 2002-2006. The sedentary anemone Anthosactis
pearseae attached directly to whalebones whereas the pom-pom anemone,
Liponema brevicornis, was found resting on soft sediment, rolling in benthic
currents, or amassed where these currents were disrupted by topography, as
at whale-falls, wood-falls, and clam fields. Both pycnogonids and anemones
were abundant during 10 of the 12 dives. The whale-fall community appears
to provide especially plentiful prey for the anemones, during stages when the
decaying carcass attracts enormous numbers of scavenging amphipods.
Like the pom-pom anemones, large pycnogonids were dramatically more
abundant at these oases than in the surrounding benthos. This predator-prey
pair potentially disperses together, and pycnogonids are a plausible selective
force in the evolution of tentacle autotomy by pom-pom anemones. Networks
of such interactions at these deep benthic oases define them as established,
though short-lived, ecological communities, not merely accidental
assemblages.
e204
P2.84 BRANDON, C.S.*; DUDYCHA, J.L.; Northeastern Illinois University,
University of South Carolina; [email protected]
Genetic variation of resource exploitation in the freshwater crustacean
Daphnia
Evolutionary divergence between two closely related populations requires
genetic variation within those populations. When genetic variation is present,
the different environments that populations encounter drive selection on traits
that better adapt the populations to their habitats. An important trait in
Daphnia, a small fresh water crustacean, is the ability to exploit different
resource levels. We set out to investigate whether clones (individuals) of
Daphnia genetically varied in their ability to exploit abundant versus scarce
resources. In this study, we used four clones from different water bodies of
each species (D. pulex, D. pulicaria). D. pulex inhabit small temporary ponds
high in resources, whereas D. pulicaria inhabit deep, stratified lakes low in
resources. For each clone, we fed them four different levels of the algae
Ankistrodesmus falcatus. We measured the juvenile specific growth rate
(ug/ug/day) for each clone at each resource level and calculated the slope
between the poorest resource level and richest resource level defined for
each species of Daphnia clones. This allowed us to determine resource
sensitivity and minimum resource requirements. Daphnia that perform well in
abundant resource conditions have more sensitive growth rates while those
that perform well in scarce resource conditions have lower minimum
resource requirements. We found that clones responded differently to
different resource levels while some clones exhibited increasing growth rates
with increasing food levels others exhibited stable growth rates across each
resource level. By constructing rank order tables, we also found that more
sensitive clones had higher minimum resource requirements, while the
converse was true for less sensitive clones.
P1.79 BRASCHAYKO, E. B.; GALT, N. J.*; BIGA, P. R.; North Dakota State
Univ.; [email protected]
A novel down-stream target of myostatin: important in muscle growth
and regulation?
Myostatin (MSTN) negatively regulates muscle growth in mammals, with
some evidence in support of a similar role in fish. MSTN levels have been
shown to be down-regulated in response to growth hormone and
up-regulated during fasting in both giant danio (Danio aequipinnatus) and
rainbow trout (Oncorhynchus mykiss). These data support a role of MSTN in
fish growth. The intent of this project was to isolate and identify a potential
downstream target of MSTN in muscle tissue. By utilizing the zebrafish
(Danio rerio) genome and rainbow trout EST databases, a novel target,
mighty was virtually cloned from rainbow trout and zebrafish. Utilizing
degenerate primers, we subsequently isolated, empirically cloned, and
sequenced mighty from the giant danio. Semi-quantitative and real-time PCR
demonstrate similar tissue distribution between mighty and MSTN gene
expression in adult giant danio. In addition, it has been demonstrated that
mighty gene expression is down-regulated during fasting, while MSTN is
up-regulated, suggesting an interaction in regulation of growth and
metabolism. We hypothesize a regulatory interaction between MSTN and
mighty, with opposing growth functions.
P1.70 BRASHEARS, Jake/A*; DENARDO, Dale/F; Arizona State University,
Tempe; [email protected]
Metabolic rate, clutch oxygen concentration, temperature and dial
patterns of contraction in brooding Burmese pythons (Python molurus
bivittatus)
Multiple models have been proposed to explain the evolution of endothermy.
The reproductive model proposed by Farmer (2000) specifies that the initial
evolution of endothermy was driven by natural selection for the maternal
ability to maintain a thermally homeostatic developmental environment, thus
increasing offspring fitness. Burmese pythons are an example of a species
that is facultatively endothermic while brooding. We are currently building a
broader study that capitalizes on this species to study the evolution of
endothermy. As part of the first stage of this study, we examined 3 brooding
females at 3 temperatures (25.5C, 28.5C, 31.5C) for 1) diurnal cycle of
female muscle contraction rate, 2) the thermal relationship between clutch
temperature, female body temperature, and nest temperature, 3) the impact
of brooding on clutch oxygen concentration, and 4) the relationship between
muscle twitch, heat production, and metabolic rate.
P1.6 BRAZEAL, K.R.*; CORNELIUS, J.M.; HAHN, T.P.; Univ. of California,
Davis; [email protected]
Variation in the first prebasic molt among House Finches, Red
Crossbills, and other Cardueline Finches that differ in reproductive
schedule
The annual replacement of feathers is a vital process for all birds. A
successful molt is important for insulation, flight capability and efficiency,
camouflage, sexually selected ornamentations and courtship displays. In
addition, growing new feathers is energetically demanding. Therefore, the
timing and pattern of molt can greatly affect reproductive success. The timing
and progression of molt was examined in adult and juvenile House Finches
(Carpodacus mexicanus) captured in Davis, California, with comparisons
being made between the sex and age classes. Furthermore, the first
prebasic molt pattern of juvenile birds was compared between
seasonally-breeding House Finches and opportunistic Red Crossbills (Loxia
curvirostra). Typically in the first prebasic molt, juvenile passerines replace
the body feathers but retain their original flight and tail feathers. However,
some species deviate from this pattern. Within the 16 North American
Cardueline Finch species (subfamily Carduelinae, family Fringillidae), House
Finches are unique in that many juveniles replace some of the flight feathers;
even the congeneric Purple and Cassins Finches do not do this. Four other
Cardueline species (including Red Crossbills) have been reported to
occasionally replace some of the flight feathers during the first prebasic molt.
Several years of field data from Red Crossbill juveniles captured throughout
the Pacific Northwest show this to be surprisingly rare, given how early
Crossbills often nest (winter). Potential explanations for these species
juvenile molt patterns are discussed, particularly in reference to differences
in flexibility of the annual reproductive cycle.
e205
P3.43 BREWINGTON, A.K.*; WEIGAND, K.L.; DEAROLF, J.L.; Hendrix
College, Conway, AR; [email protected]
Prenatal steroids: effects of betamethasone on the guinea pig (Cavia
porcellus) rectus thoracis muscle
Glucocorticoids are commonly injected into mothers expected to give birth
prematurely to promote maturation of vital organs. Although these steroids
increase the chance of survival, there is little known about their effects on
breathing muscles. Based on previous studies of the effects of
glucocorticoids on skeletal muscle, we hypothesize two changes in the
treated rectus thoracis, an accessory muscle of the ventilatory pump in
guinea pigs (Cavia porcellus): less fast-twitch fibers and smaller fibers.
Pregnant Hartley guinea pigs (Cavia porcellus) were injected with
betamethasone (0.5 mg/kg body weight) or sterile water at 65%, 75%, and
85% gestation. Muscle samples collected from the fetuses were cut and
stained using the myosin ATPase assay. Digital images of the stained
sections were then captured using an image analysis system. These images
were analyzed to obtain fiber-type percentages by number, and up to
twenty-five fibers of each type were measured for least diameter and area
using Scion Image. There was not a significant difference between the
percentage of fast-twitch fibers in the control (92.2%) and treated (92.0%)
muscles. However, the fiber diameters of the treated (fast: 12.900.25 m,
slow: 14.140.21 m) rectus thoracis were found to be significantly smaller than
those in the control muscles (fast: 14.380.25 m, slow: 17.800.24 m). These
findings support the hypothesis that steroid treatment results in smaller
muscle fibers. Smaller fibers would cause the muscles of treated babies to
not be able to produce as much force as muscles in babies not exposed to
steroids. Therefore, these results raise concern of possible breathing muscle
weakness in babies treated with betamethasone.
P1.49 BRIGHT, J A; University of Bristol; [email protected]
Modelling cranial sutures in Finite Element Analysis: a validation study
using the domestic pig
The use of Finite Element Analysis (FEA) to investigate feeding mechanics is
becoming increasingly common. However, what little work has been done to
validate the technique has been conducted almost exclusively on primates.
This work represents the first attempt to validate cranial FE models of a
non-primate mammal, by comparing specimen-specific models of the
domestic pig, Sus scrofa, with strain data collected in vitro. Cranial sutures
have been largely overlooked in FE models, despite evidence suggesting
their important structural role as "shock-absorbers", dissipating dangerously
high strains. The pig models were loaded at the tooth row, and potentially
functionally important sutures (zygomatic, coronal, maxillary-premaxillary)
introduced in one of three ways; fused, open, or assigned elastic properties
of collagen within sutures. Results show that sutures notably affect strain
patterns throughout the skull, and more attention should be paid to their role
in cranial FE modelling.
P1.123 BROCIA, S.; DING, Z.*; ROOT, R.G.; Lafayette College;
[email protected]
An improved model of vertebrate muscle force generation
Mathematical models of the generation of force in muscles by way of
crossbridges date back to work by Huxley in the 1950s. The Huxley Model is
based on a two-state model for crossbridges; a crossbridge is either attached
to an actin filament or detached. This approach is inadequate to describe the
conversion of chemical to mechanical energy by crossbridges. More recent
models, like that of Tanner et al. (2007), offer more realism in the conversion
of energy at the expense of computational complexity. We offer a three-state
model that is more up-to-date than Huxley, but simpler than Tanner, and
apply it to the study of swimming fish. This model includes pre-powerstroke
and post-powerstroke states of attachment. Using it, we analyzed the tension
generated and change in length of a myofibril over time under fixed loading.
The model demonstrates the transition to constant velocity shortening
predicted by Hill's law with transient behavior similar to that observed by
Jewell & Wilkie (1958). This suggests that the model captures fundamental
features of muscle physiology, and serves as a useful baseline for further
investigations.
P2.187 BRODSKY, Sasha*; WALTERS, Linda; HOFFMAN, Eric;
SCHNEIDER, Kimberly; University of Central Florida;
[email protected]
Thermal Tolerances of the Invasive Mussel Mytella charruana
Mytella charruana is an invasive bivalve that, in the past five years, has been
found fouling docks and oyster reefs on the southeastern Atlantic coast of
the U.S. It originates from both coasts of South America. We have been
trying to better understand this species by studying its physiological
tolerances. We first tested M. charruana's cold temperature tolerances. In
14-day trials, salinity ranged from 9-15 ppt based on the collecting site. We
started out using 6, 13, and 20C water. 20C was the baseline because this
was the temperature at which we collected mussels. There was no survival
at 6C, but significant survival at 13 and 20C (58 and 41%, respectively). So
we tested a narrower range of temperatures (6, 9, 11, and 13C). All M.
charruana died at 6C, but survived at 9, 11, and 13C (12, 13, and 31%,
respectively). These trials were carried out using 5-day adjustments between
temperature treatments. Next, we conducted a shock temperature trial. All
mussels were immediately placed in 6, 9, or 11C from 20C water. Six hours
later, the temperature was adjusted back to 20C. At 6C, there was low
recovery (12%), but at 9 and 11C (66 and 71%, respectively), M. charruana
had a high recovery. Warm temperature trials are currently underway, with
one trial completed. 20, 23, 28, and 31C waters were tested using 5-day
adjustments between treatments. There was little mortality at any of these
temperatures, so a new trial is underway with 20, 31, and 36C treatments.
Once a maximum temperature for survival is known, shock trials will be run.
We have determined the thermal minimum for M. charruana (6C), and hope
to soon know its thermal maximum. This information can help us predict
where this invader may spread in the future.
e206
P3.40 BROWN, J.W.; University of Illinois at Urbana-Champaign;
[email protected]
Directionally Mediated Escape Swimming in the Scallop
Despite the copious literature available and robust dynamic modeling on the
ability of scallops to employ jet propulsion, no investigation has been
undertaken to assess scallops' ability to control their directionality during an
escape swimming event. Twenty specimens of the Pacific Northwestern
species Chlamys hastata were provoked using a severed arm from the sea
star Pycnopodia helianthoides, a common predator, in order to elicit the
escape swim response. A significant correlation was shown to exist between
the anterior-posterior laterality--but not absolute position along the scallop's
mantle--of predatory stimulus and the ensuing direction of rotation; namely,
stimuli applied to the anterior mantle consistently effected a counterclockwise
rotation (when viewed from above the animal) during the initial escape swim,
while posterior stimulation resulted in a clockwise rotation. Stimulation at the
ventral end of the dorsal-ventral axis demonstrated a strong
counterclockwise bias, suggesting a possible morphological or neurological
asymmetry underlying this response. To these ends, visualization of the two
dorsal jets and an additional diffuse ventral jet at the onset of swimming
revealed the ability to fire the anterior or posterior dorsal jets exclusively in
accordance with the preferred direction of rotation. Rudimentary modeling of
this phenomenon is explored.
P2.160 BRUBAKER, J.L.*; SCHULKIN, J.; ROMERO, L.M.; Tufts University,
Georgetown University; [email protected]
Exogenous corticosterone alters behavior in House Sparrows (Passer
domesticus)
In response to a stressor, animals undergo physiological changes as well as
behavioral changes which ultimately allow the animal to better cope with the
stressor. This study examined the effects of exogenous corticosterone on
behavior in the House Sparrow (Passer domesticus). Birds were injected
with either 0g, 50g, or 100g of corticosterone suspended in peanut oil and
then subjected to a crowding stressor. The crowding stressor consisted of 0,
2, or 5 intruder birds entering the focal birds cage. Trials were videotaped
and scored for the frequency of 8 aggressive and maintenance behaviors.
Increased corticosterone doses were associated with an increase in activity
and maintenance behaviors whereas an increased number of intruders was
associated with increased aggressive behaviors. Additionally, other
aggressive behaviors were dependent on the interaction of corticosterone
dose and number of intruders. This provides further evidence that the
behavioral effects of corticosterone are context dependent. Furthermore, this
study serves as a foundation upon which the interaction between
corticosterone and other behavioral agonists and antagonists can be tested.
P3.56 BURCH, Sara H.; Stony Brook University, NY;
[email protected]
The Relationship Between Muscle Attachment Site Size and Function in
the Avian Hind Limb
The utility of osteological correlates of muscle attachment sites (e.g., scars,
crests and tubercles) in the reconstruction of function and behavior in
vertebrates is controversial. Whereas not every muscle leaves a scar, it has
been suggested that differences in the relative size, strength and/or function
of a muscle may be reflected in the relative development of an osteological
correlate. This relationship has been systematically studied thus far only in
an intraspecific context. Birds exhibit a wide range of hind limb locomotor
adaptations ranging from cursoriality (Paleognathiformes) and diving
(Gaviiformes) to predation (Falconiformes) and scansoriality (Piciformes), but
the musculature of avian hind limbs is relatively conserved across taxa. This
makes birds an ideal group for examining functional correlates of muscle
attachment site size. Several bony crests and projections of the femur and
tibia, each representing the attachment site of a functionally relevant muscle,
or group of muscles, were photographed and measured in multiple avian
taxa, representing eight distinct locomotor categories. The area of each
osteological correlate was regressed against midshaft diameter of the bone,
and an analysis of covariance indicated that the functional categories differed
significantly (p<0.05) from each other for each muscle examined. Certain
taxa, notably divers, climbers and cursors, exhibited highly specialized
functional adaptations that correlate to either increased or decreased muscle
use at that attachment site. These results suggest that variation in
osteological correlates is likely to have utility when reconstructing functional
or behavioral categories from osteological specimens, including those of
fossils.
P2.190 BURMESTER, E.M.*; FIELDS, P.A.; Franklin and Marshall College;
[email protected]
Changes in solute composition in mussel (Mytilus galloprovincialis) gill
extracts after exposure to high temperature
Although low-molecular-mass solutes have the potential to affect the function
and stability of macromolecules in the cell, little work has been done to
describe how relative concentrations of these solutes may change acutely in
response to environmental stress. Using the blue mussel Mytilus
galloprovincialis acclimated to 13C, we examined how elevated temperature,
and duration of exposure to elevated temperature, altered the relative
concentrations of low-molecular-mass compounds in gill tissue. We used
high pressure liquid chromatography - mass spectrometry (MS) to measure
relative changes in low-molecular-mass compounds present in gill extracts at
intensities above an arbitrary cut-off. We found that two compounds
increased significantly and six decreased significantly in concentration after
exposure to high temperatures (26C, 29C, 32C or 35C for one hour, with one
hour of recovery at 13C). In our time course experiment, (32C exposure for
varying times, 13C recovery for one hour), changes in concentration
occurred rapidly (within 15 min), but longer exposures (up to four hours)
reduced the magnitude of change. Concentrations of these compounds
changed dramatically (up to 2X increase and 5X decrease) compared to
control. We are currently using high-resolution MS and MS/MS to identify the
compounds that change in concentration most significantly.
e207
P3.58 BUTCHER, M.T.*; PARRISH, J.H.A.; BLOB, R.W.; Youngstown State
University, Clemson University; [email protected]
Loading patterns of the femur in opossum ( Didelphis virginianis )
during terrestrial locomotion
Previous studies have found that mammalian limb bones typically are loaded
predominantly in bending with minimal torsion, whereas the limb bones of
non-avian reptiles (and amphibians) experience considerable torsion in
addition to bending. However, most data on limb bone loads for mammals
have been collected from large or cursorial species (e.g., horses, dogs,
sheep) in which the limbs tend to be held upright. To better clarify the
evolutionary timing of the distinctions in bone loading patterns between
reptiles and mammals, we measured in vivo terrestrial locomotor strains in
the femur of the Virginia opossum (Didelphis virginianis), a marsupial that
uses more crouched limb posture than previous mammals from which bone
strains have been recorded, and which belongs to a clade phylogenetically
between reptiles and the eutherian mammals studied previously. If limb bone
loading patterns in opossum show torsion similar to amphibians and
non-avian reptiles, then the patterns shown across these diverse taxa likely
reflect the ancestral condition of tetrapod limb bone design. Strain recordings
indicate the presence of both bending and a moderate amount of off-axis
loading in the opossum femur, suggesting elevated limb bone torsion
compared with most previously studied mammals. Supported by NSF
I0B-0517340.
P3.169 BUTLER, L.K.*; ROMERO, L.M.; Tufts University;
[email protected]
Relationships between corticosterone concentrations and the onset,
progression, intensity, and rate of molt in two free-living birds
The post-breeding (prebasic) molt in birds is typically correlated with a drop
in baseline and stress-induced concentrations of the primary avian
glucocorticoid, corticosterone (CORT). However, to our knowledge, details of
the relationships between CORT and molt onset, molt progression (the stage
of molt), molt intensity (the number of growing feathers), and molt rate (the
speed with which molt is completed) are unknown for any free-living bird. We
investigated these relationships in two seasonally-breeding songbirds, the
Black-capped Vireo (Vireo atricapilla) and the White-eyed Vireo (V. griseus),
on their breeding grounds in Texas, USA. We detailed the timing, progress,
intensity, and rate of molt in two populations of each species, and correlated
these parameters with baseline and stress-induced CORT concentrations.
CORT concentrations started to decline weeks before the onset of molt, were
lowest near the onset of molt, and varied little with molt intensity, progress, or
rate. These results do not contradict the widely held idea that CORT is lower
during molt in order to avoid CORT's negative effects on protein synthesis
(i.e., feather production), but the lack of a close temporal connection
between the seasonal decline in CORT and the onset of molt, and the lack of
strong relationships between CORT concentrations and the intensity,
progression, and rate of molt, suggest that the seasonal decline in CORT
concentrations in temperate birds may have other functions as well.
P1.98 CAMPOS, E.O.*; CALDWELL, R.L.; Univ. of California, Berkeley;
[email protected]
Quick Forward Escape Swimming in the Stomatopod Crustacean
Odontodactylus havanensis
Although metachronal beating of oar-like appendages is a common means of
swimming among aquatic organisms, it is typically associated with slow
swimming speeds. I characterized the escape swimming of the stomatopod
crustacean Odontodactylus havanensis, which uses metachronal rowing to
achieve an exceptionally fast escape response. This unique situation may be
related to several factors including body size, broad pleopod morphology,
and the evolutionary legacy of the formidable stomatopod raptorial
appendages. Ten individuals were videotaped at 30 and 500 frames per
second while escape swimming. Propulsion was provided by the beating of
the first five pairs of abdominal appendages, pleopods, in an adlocomotory
metachronal wave. The most posterior pair of pleopods began the power
stroke first, and was followed by the power stroke of the next anterior pair of
pleopods. This sequential pattern continued until all five pairs of pleopods
completed a power stroke. No coasting phase was observed and all five
pairs of pleopods began their recovery stroke nearly simultaneously.
Escaping stomatopods can approach speeds of 30 body lengths per second,
comparable to the escape swimming performances of jetting squid and
tail-flipping shrimp-like crustaceans.
P3.131 CARLETON, JB*; MORGENSTERN, N; PARKER, C; RENN, SCP;
Reed College; [email protected]
One Bad Mother: Maternal Aggression in the African Cichlid
Astatotilapia burtoni.
Thirty years of research have contributed to our understanding of the
molecular, hormonal, and physiological mechanisms of the socially regulated
switch between dominant and subordinate phenotypes among males of the
African cichlid species Astatotilapia burtoni. Meanwhile, the female
phenotypes have been largely ignored by all but a few studies regarding the
reproductive cycle and affiliative behavior. Females of a recently collected A.
burtoni wild stock from Zambia display a "good mother" phenotype that
includes defensive aggression to protect free-swimming fry for up to 15 days
post-release, whereas labstock females show similar aggression but eat their
fry within 2-3 days post-release. The behavioral difference is likely due to
inadvertent artificial selection in the lab, as suggested by good-mother
phenotype observed in F1 wildstock that have been reared under standard
lab conditions. We describe this behavior in detail through repeated,
ten-minute focal observations using Jwatcher and an ethogram adapted from
that used for males. Hormone measurements from excreted water samples
are used to quantify the hormone profile during and brooding and
post-release maternal care. Females have been observed under various
social situations, including intruder challenge in order to address the
challenge hypothesis as it might apply to female territoriality. Cross-fostering
experiments were conducted to determine whether the differing level of
maternal care is induced by possible differences in the behavior of the fry.
We found that the genotype of the fry did not affect maternal care, however
wildstock fry exhibited increased maternal affiliation but similar schooling
behavior compared to labstock fry. This work establishes a female model for
aggression, which will be explored at the hormonal, molecular and genetic
level.
e208
P2.166 CARLISLE, S.L.*; KNAPP, R.; NEFF, B.D.; Univ. of Oklahoma, Univ.
of Western Ontario; [email protected]
Steroidogenic enzyme activity in the three alternative male
reproductive morphs of bluegill sunfish
Among the great variety of reproductive modes exhibited by teleost fishes,
one that has received considerable attention is the presence, within a single
species, of males that practice distinct alternative reproductive tactics
(ARTs). Bluegill sunfish (Lepomis macrochirus) are particularly interesting in
this regard because they have three male morphs that differ in reproductive
behavior, morphology, and physiology. Parental males court females and
provide care for the resulting offspring. Two non-parental morphs, termed
sneakers and satellites, use sneaking or female mimicry behaviors,
respectively, to steal fertilizations from parental males. Among the morphs
physiological differences are differences in circulating 11-ketotestosterone
(KT) and cortisol levels and various sperm characteristics on the day of
spawning (Neff, Fu and Gross 2003; Neff and Stoltz 2006; Knapp and Neff
2007). The morph difference in KT and cortisol is of particular interest for
understanding endocrine mediation of ARTs because the biosynthetic
pathways of these hormones have two enzymes in common:
11β-hydroxylase (11β-H) and 11β-hydroxysteroid dehydrogenase
(11β-HSD). We hypothesize that the relative activity of these enzymes in
different tissues plays a role in endocrine mediation of the morph differences
in behavior and/or spermatogenesis. To begin to test this hypothesis, we are
currently comparing the activity of 11β-H and 11β-HSD (measured as the
amount of substrate converted to product/min/mg protein) in gonad, liver,
and interrenal tissues. We will describe our findings and discuss the
implications of our results for understanding the mechanisms by which
steroid hormones mediate behavioral and physiological aspects of the male
ARTs in bluegill and in other teleost species with ARTs.
P2.80 CARR, J.A.*; MARSH, R.L.; Northeastern University;
[email protected]
A Swimming Muscle with a Novel Function
During swimming muscles must shorten and produce positive work to
generate thrust to balance the drag on the body and it is generally assumed
that most major active muscles will contribute to this function. The goal of
this study was to use sonomicrometry and electromyography to determine
whether the function of the flexor cruris lateralis (FCL) was to produce
positive work during swimming in the mallard. We chose to measure the
function of the measure the function of the FCL in the mallard for several
reasons. Based on blood flow and anatomical studies, the FCL appears to
play an important role during swimming. The FCL, is a large muscle with a
complex origin and insertion in cursorial locomotors. However, the FCL
appears to have been significantly modified in birds that employ swimming
as a primary form of locomotion. Based on our results, the FCL of the
mallard appears to function in both terrestrial locomotion and during
swimming. During terrestrial locomotion, the FCL actively shortens by
approximately 10-15% during stance, correlating with a large knee flexion at
low speeds and increased hip extension at high speeds. During swimming
the FCL is largely isometric during the power stroke and shortens by 3-7 %
during the return stroke. We hypothesize that the major role of the FCL
during the power stroke in swimming is to counteract the reaction force
produced by ankle extension, thus holding the knee and hip in a fixed
position, decreasing the amount of drag and increasing the effectiveness of
the power produced by the ankle extensors. Supported by NIH AR47337 and
NSF IOB-0542795 to RLM.
P2.97 CARRENO, C. A.*; SMITH, K. K.; Duke University, Durham, NC;
[email protected]
Limb specification and growth initiation in Xenopus laevis: Possible
heterochronic mechanisms
In most vertebrates, the fore and hind limbs arise nearly synchronously, early
in development. In anurans, however, the hindlimbs appear before the
forelimbs. Further, limb development occurs late in the developmental
period, well into the free-swimming larval stage and well after the body plan
and major organ systems are established. In vertebrates, early limb
patterning is generally understood. The identity of the forelimb is through
Tbx5, whereas Pitx1 and Tbx4 identify the hindlimb. The feedback loop
between Fgf10 and Fgf8 regulates the initiation and outgrowth of both fore
and hind limbs, and their area of expression is restricted to the hindlimb field
by Wnt8 and to the forelimb field by Wnt2. Compared to other vertebrates,
little is known about the development of the limbs in anurans. We have
cloned the genes mentioned above from Xenopus laevis and we are using
whole-mount in situ hybridization to observe patterns of expression during
specification of the limb fields and the initiation of limb growth in late stage
embryos (tadpoles). By comparing patterns of expression, we can identify
heterochrony in gene expression and understand the developmental
mechanism that may be responsible for the asynchrony of limb development
in anurans.
P3.116 CARROLL, K.N.*; SCULLY, T.A.; BROWN, K.M.; CHENG, Y.;
MATEER, E.; DZIRLO-AYVAZ, M.; ANITOLE-MISLEH, K.; The George
Washington University; [email protected]
A preneuronal serotonergic system drives morphogenesis in sea
urchin embryos
In the sea urchin embryo, pharmacological studies in our lab and others have
suggested that serotonin may initiate cell movement processes during
gastrulation. To further investigate the role of a serotonergic system in
embryogenesis, we measured levels of serotonin and its precursor and
metabolites, as well as mRNA levels and enzyme activity of the serotonin
synthetic enzyme, tryptophan hydroxylase, in Lytechinus pictus blastula- and
gastrula-stage embryos and larvae. Serotonin levels peak in mesenchyme
blastula embryos, immediately prior to gastrulation, and at mid gastrula and
late pluteus larva stages. Alterations in serotonin levels mostly follow the
measured fluctuations in serotonin synthesis and metabolism. Preliminary
studies suggest that preneural embryos may utilize a different enzyme,
phenylalanine hydroxylase/tryptophan hydroxylase (PAH/TPH), than that
used in larval neurons (TPH) to hydroxylate tryptophan. The gastrulation
process is most sensitive to inhibitors of mammalian types 1, 2, and 7
serotonin receptors. These antagonists blocked the initial invagination of the
vegetal plate, whereas lower concentrations delayed the initiation of the
secondary phase of gastrulation with little effect on subsequent development.
Serotonin or dibutyryl cyclic AMP, coincubated with ritanserin or
chlorpromazine, type 2 and 7 receptor antagonists, at least partially rescued
embryos from gastrulation inhibition. Homology searches of the sea urchin
genome identified types 1, 2 and 7 receptors, but only 2 and 7 are linked to
an increase in cyclic AMP following activation by serotonin. In sum, sea
urchin embryos contain a serotonergic system that may regulate the early
gastrulation process through types 2 and/or 7 serotonin receptors.
e209
P3.120 CARROLL, Margaret A.*; SKEETE, Dereck; CATAPANE, Edward J.;
Medgar Evers College/CUNY; [email protected]
It's Time to STEP into Science at Medgar Evers College
Over the next decade, demand and job opportunities in science and
engineering (S&E) are expected to continue to grow and questions arise as
to whether America will be able to attract enough young people into Science,
Technology, Engineering and Mathematics (STEM) to maintain a S&E
workforce that is competitive globally; and considering recent U.S. Census
reports, will our future STEM workforce reflect the racial and ethnic diversity
projected for the growing U.S. population? In 2006, the authors initiated a
STEP into Science program at Medgar Evers College. Funded under the
Science, Technology, Engineering and Mathematics Talent Expansion
Program (STEP) of the National Science Foundation (NSF) Division of
Undergraduate Education, the main goal is to increase the number of STEM
majors that graduate with baccalaureate degrees in Biology or Environmental
Science. The program has had great success implementing the use of peer
recruiters to attract more high school, transfer, and non-science college
students into STEM majors and places emphasis on the role of
undergraduate research experiences as a successful strategy to increase the
quality and retention of science majors through their B.S. degree. Since the
inception of the program, total STEM enrollment has more than doubled and
the number of majors actively engaged in research has risen 38% with a
concurrent increase in student research presentations at scientific
conference, and the number of students receiving external research
internships and travel awards to attend national conferences. STEM
graduates have also increased and the program anticipates that these and
future STEP into Science graduates will continue on to Masters and Doctoral
programs in STEM and ultimately enter rewarding careers in the science
enterprise. Supported by grant 0622197 of the DUE Program of NSF.
P3.41 CARRUTH, W C*; ENTZ, J W; MARLEY, P H; ROSTAL, D C; Georgia
Southern University; [email protected]
The relationship between egg size, clutch size, pelvis size & body size
in Gopherus polyphemus
Female size is directly related to reproductive output. A larger sized female
has the ability to invest more energy into its offspring. Reproduction is
viewed as a model; a female can either create fewer but larger offspring or
more but smaller offspring. In many chelonian species egg size changes with
body size; however, in Gopherus polyphemus egg size does not strongly
correlate with carapace size. A higher correlation was found between egg
size and pelvic size in G. polyphemus, but not enough to account for the
variation seen in the egg sizes. Similar to previous studies on various
freshwater turtles, it is predicted that mass, clutch size and a PCA will better
correlate with egg size. For the past fourteen years a life history study of G.
polyphemus from three different populations has been carried out. The
females were X-rayed and morphometric measurements were taken to
determine female reproductive characteristics. In order to test the
predictions, X-rays will be measured from three different populations dating
from 1994 to present. The females Straight Carapace Length (SCL), pelvic
aperture opening, clutch size, and two dimensions of the eggs will be
measured in the X-rays. In addition to X-ray measurements, field weights
and measurements will be used to compare with X-ray data.
P1.111 CARUSO, M.A.*; KITTILSON, J.D.; BLAUFUS , P.C.; SHERIDAN,
M.A.; North Dakota St. Univ.; [email protected]
Rainbow trout insulin receptors: cloning, patterns of mRNA expression,
and regulation by fasting
Insulin (INS) plays a critical role in the growth, development, and metabolism
of vertebrates. In this study, a unique cDNA encoding a fourth insulin
receptor subtype (IR4) was isolated, cloned and sequenced from the liver of
rainbow trout. A 1525-bp cDNA encoding a partial amino acid sequence of
the beta-subunit and the 3' untranslated region (UTR) was obtained. IR4
shares 75.5%, 73.1%, 68.3% deduced amino acid identity with previously
characterized trout IR1, IR2, IR3, respectively. Quantitative real-time PCR
revealed that the four IR mRNAs were differentially expressed, both in terms
of distribution among tissues as well as in terms of abundance within
selected tissues of juvenile trout. IR1 mRNA was most abundant in muscle
(white, red, cardiac) but least abundant in adipose, whereas IR3 and IR 4
mRNA were most abundant in adipose and liver. All IR subtypes were
detected over the course of embryonic development; levels of IR3 and IR4
remained relative constant from pre-hatch (29 days post-fertilization, dpf) to
post-hatch (90 dpf), whereas levels of IR1 and IR2 tended to increase during
this period. Fasting for 4-6 weeks increased the expression of IR1 and IR4 in
liver and cardiac muscle. These findings provide insight into the evolution of
IRs as well as into the pattern and regulation of IR expression. (Supported by
NSF IOB 0444860 to M.A.S.)
P1.82 CARY, Gregory; CUTTLER, Anne; KUSEMA, Escar; MYERS,
Jennifer; DUDA, Kirsten; TILDEN, Andrea*; University of Washington, Colby
College; [email protected]
Neuroprotective and neuritogenic effects of melatonin on crustacean
x-organ cells
The vertebrate pineal hormone melatonin has protective effects in the
mammalian nervous system. These effects are both receptor-mediated and
non-receptor-mediated. Melatonin has not been extensively studied in
invertebrates; however, invertebrates do produce melatonin, with daily
variations that suggest a circadian pattern as in vertebrates. Crustaceans
respond to exogenous melatonin with changes in activity patterns, glucose
metabolism, and cardiac rate, all of which are influenced also by
well-characterized neuropeptide products of the x-organ/sinus gland system
in the eyestalk. We studied the influence of melatonin on neurite growth of
x-organ cells from the fiddler crab Uca pugilator. In culture, these cells grow
neurites with extensive arborizations within the first 48 hr. Melatonin, 1 M,
1nM, and 1 pM, significantly increased neurite growth versus control cells
after 24 hr in culture. The physiological concentrations, 1 nM and 1 pM,
increased growth at 48 hr also, whereas the pharmacological 1M dosage
showed desensitizing effects by this time. Luzindole, a vertebrate melatonin
receptor antagonist, had agonist-like activity in these crustacean cells,
indicating a potentially different type of membrane receptor from vertebrates.
Melatonin also had protective effects, reversing the neurite-inhibiting
administration of hydrogen peroxide. This neuroprotective influence of
melatonin is likely due to the ubiquitous ability of melatonin to scavenge free
radicals directly. Results of this study indicate roles of melatonin in the
crustacean nervous system that are analogous to its roles in the vertebrate
nervous system.
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P2.16 CATENAZZI, A*; LEHR, E; University of California, Berkeley,
Staatliche Naturhistorische Sammlungen Dresden; [email protected]
Ecotones as biodiversity hotspots for high-Andean anurans
Amphibians are declining worldwide, with some authors suggesting that
mass extinctions have occurred over the past two decades and will continue
into the future. Andean anurans are among the hardest hit by declines, with
habitat destruction/fragmentation, infection by chytrid fungus, climate
change, and an interaction of these factors as the most likely causes of
declines. Conservation efforts should favor the protection of habitats most
likely to support amphibian species and of areas with wide elevational
ranges, which would allow for upward species migration in places where
average temperatures increase. High-Andean amphibian communities are
rich in endemic species which often have very limited distributions, yet they
are vastly understudied. Gaining a better understanding of the factors that
influence local and regional species richness will improve our capacity to
select priority areas for amphibian conservation in the Andes. In this study,
we explored the hypothesis that ecotones between forest and grassland
habitats are biodiversity hotspots for high-elevation anurans in southern
Peru. Our analysis was based on data collected from over 100 leaf-litter
quadrats, which were sampled between 3,000 and 3,700 m. Despite a
general trend towards decreasing species richness as a function of elevation,
the forest-grassland ecotone had significantly higher frog density and
biomass when compared to forest or grassland habitats alone. In addition, a
number of newly discovered species were all collected in ecotonal habitats or
forest habitats adjacent to ecotones. The results of our study suggest that
forest-grassland ecotonal habitats are biodiversity hotspots for anuran
species in the Andes, and that these habitats should be considered as target
areas for amphibian conservation.
P1.152 CEASE, Arianne*; HAO, Shuguang; ELSER, James; KANG, Le;
HARRISON, Jon; Arizona State University, Chinese Academy of Sciences;
[email protected]
High density and high nitrogen: A dual stressor for grasshoppers?
Insects respond to high density in a variety of ways that, if exposed during
larval development, can culminate in drastic changes in physiology and
morphology. Some of these changes can be beneficial in aiding dispersal
from a crowded habitat. For grasshoppers and other insect herbivores that
tend to be nitrogen (N) limited, plant quality also affects these characters.
High dietary N is correlated with increased survivorship, growth, and
fecundity, while low dietary N is deleterious and can induce dispersal.
Despite the intrinsic relationship between population density and dietary N,
limited studies offer insight as to how the interaction of these two factors
impact insect development. To gain a better understanding, we tested this in
a dominant grasshopper species in Chinas Xilin River basin region, Odaleus
asiaticus. Grasshoppers were assigned to 1 of 4 treatment groups (high or
low density and N fertilized or unfertilized grass). There was a significant
interaction effect between diet and density. Grasshoppers reared in high
density and fed high N diets had a significantly lower growth rate, increased
development time, decreased adult mass, and increased metabolic rate (MR)
as compared with the other three treatment groups. Increased MR leads to
increased energy expenditure and could explain decreased adult mass. It is
also an indicative dispersal characteristic in this family. These results
suggest that insects reared in high density are more sensitive to changes in
dietary N, perhaps these effects are strictly deleterious due to a compound of
stressors, or perhaps the interaction induces development of dispersal
characters. This research was partially supported by NSF EAPSI fellowship
and Sigma Xi GIAR to AJC.
P1.71 CHAMPAGNE, A.M.*; MUNOZ-GARCIA, A.; WILLIAMS, J.B.; The
Ohio State University; [email protected]
Cutaneous water loss and lipids in the stratum corneum of mesic
horned larks (Eremophila alpestris praticola) and five species of desert
larks
The stratum corneum (SC), the outer layer of the epidermis in birds and
mammals, forms a barrier to water vapor diffusion through the skin. The
avian SC is composed of corneocytes embedded in a lipid matrix of
cholesterol, free fatty acids, triglycerides, ceramides, and cerebrosides.
Cutaneous water loss (CWL) accounts for over half the total water loss in
birds. Because birds in deserts face a hot, desiccating environment,
selection to reduce CWL at moderate ambient temperatures may have been
stronger in desert birds than in mesic birds. Previous studies in our lab have
shown that changes in the ratios of lipid classes in the SC may influence
CWL in birds. Appropriate ratios of ceramides, cerebrosides and free fatty
acids seem necessary for the formation of intercellular lipid bilayers, called
lamellae. The molecular organization of these lamellae affects CWL. In this
study, we compared rates of CWL and SC lipid composition of horned larks
from central Ohio (Eremophila alpestris praticola) with those of five species
of larks from deserts. E.a. praticola had higher rates of CWL at thermoneutral
temperatures and a higher ratio of ceramides to cerebrosides in the SC than
desert larks, a result consistent with our findings in other bird species. We
also found that the lipid composition of the SC was associated with CWL in
horned larks.
P2.113 CHANG, J.L.; Univ. of Miami; [email protected]
Sexual Dimorphism of the Second-to-Fourth Digit Length Ratio (2D:4D)
in the Strawberry Poison Dart Frog (Oophaga pumilio) in Costa Rica
The second-to-fourth digit ratio (2D:4D) is a well-studied sexual dimorphism
that likely arises as a result of prenatal androgenic effects on homeobox
gene expression. This dimorphism exhibits interesting phylogenetic patterns
in which females have larger ratios than males among most mammalian
species and males have larger ratios than females in most avian and
reptilian species. However, 2D:4D has not been measured in more basal
taxa such as amphibians. In this study, 2D:4D of all four feet and
snout-to-vent length (SVL) were measured in 40 male and 44 female
free-ranging adult Oophaga [=Dendrobates] pumilio frogs to investigate the
existence and patterning of sexual dimorphism. The 2D:4D of the rear feet
varied significantly by sex with males having a larger ratio than females. The
digit ratio of the front feet did not differ between the sexes. SVL or its
interaction with sex did not affect 2D:4D on any of the feet. These results
indicate that 2D:4D in an anuran is both sexually dimorphic and follows a
pattern between the sexes similar to that of diapsid species.
e211
P2.162 CHANTAROJWONG, T.M.*; PROPPER, C.R.; Northern Arizona
University ; [email protected]
Gonadotropin-Releasing Hormone Does Not Enhance Male Detection of
Female Pheromones in Xenopus tropicalis
Amphibians produce pheromones which are known to affect communication
and courtship behavior. There are several examples of courtship-related
pheromonal communication occurring in urodele species and very few
examples of pheromone communication in anurans. We investigated the
frog, Xenopus tropicalis, to further identify the capacity for pheromonal
communication and to determine whether treatment with
gonadotropin-releasing hormone (GnRH) increases male sensitivity to
pheromones. Previous studies in our lab have found that males spent a
significant amount of time in the female arm of a y-maze than the control arm
(P=0.01). GnRH is a neuro-hormone that is instrumental in several
reproductive physiological processes and is known to impact both
reproductive behavior and response to odorants. In this study, we
investigated the impact of injected GnRH on pheromone detection in males.
Males were injected intraperitoneally either with 0 ug or 10 ug GnRH in
Ringers. Animals were then placed in a Y-maze and given the choice of an
arm containing water from female conspecifics or control water. Both GnRH
and amphibian Ringers injected males combined spent more time in the
producer arm than in the control arm (P=.0395). However, males injected
with GnRH did not spend a significantly more time in the producer arm than
males injected with amphibian ringers (P=.819). We conclude that 10 ug
GnRH does not have a significant impact on males sensitivity to female
pheromones; however, we confirmed that female anurans also produce
pheromones.
P1.120 CHAO, Erica*; KIM, Hyun-Woo; THOMPSON, Matthew D; MYKLES,
Donald L; Colorado State University; [email protected]
Troponin-C cloning and tissue expression in the American lobster,
Homarus americanus
Troponin-C (Tn-C) regulates muscle contraction by binding calcium. Three
Tn-C isoforms have been identified in lobster (Tn-C1, Tn-C2a and Tn-C2b) and
have previously been sequenced at the amino acid (aa) level. We cloned the
full-length nucleotide (nt) sequence of Tn-C1 (679 kb, 150 aa, 17.0 kDa), a
partial sequence coding for Tn-C2a, and four full-length nucleotide sequences
coding for novel lobster Tn-C isoforms designated Tn-C3 (1128 kb, 150 aa,
16.9 kDa), Tn-C4 (733 kb, 108 aa, 12.1 kDa), Tn-C5 (2884 kb, 149 aa, 17.3
kDa) and Tn-Cx (2242 kb, 154 aa, 16.9 kDa). The former four sequences
were found via RT- and RACE-PCR; the latter two were ESTs sequenced via
RT-PCR. The translated aa sequence of Tn-C4 was N-terminally truncated
(38 aa). Tn-Cx was highly divergent from the other lobster Tn-C sequences.
Its translated aa sequence had a 71 aa N-terminal truncation and a
C-terminal 76 aa proline-rich extension. Expression of the six Tn-C
sequences across a range of tissue types in lobster will use end-point
RT-PCR. Fiber-type-specific expression will be quantified by real-time PCR.
Further work will determine the relationship between Tn-C isoform
expression patterns and: muscle functional properties; molt cycle; and
expression of myostatin, which is thought to inhibit muscle growth prior to
molting. Supported by NSF (IBN-0618203).
P1.164 CHE, JAMES*; DORGAN, KELLY M; University of California,
Berkeley; [email protected]
It's tough to be small: Dependence of burrowing kinematics on body
size
In marine muds, the polychaete Nereis virens burrows by the method of
crack propagation, which involves the extension of a crevasse rather than
ingestion or excavation of sediment. In gels with different material properties,
Nereis virens alters its burrowing behavior as predicted by fracture
mechanics theory. Observations of the marine worm Cirriformia moorei
agree with this wedge-like model of locomotion. My experiments involved
video analysis of worms ranging from 0.01 to 0.44 g wet weight burrowing in
gelatin, a transparent analog for muddy sediment. Following predictions from
fracture mechanics theory, several behavioral and kinematic parameters
correlate with body size. When propagating the crack, smaller worms have
blunter head tips, thicker (relative to body size) anterior regions, and a
greater relative change in body thicknesses (amplitude of peristaltic wave).
Smaller worms tended to contort their hydrostatic bodies more than larger
worms in order to focus enough stress at the crack tip to extend the burrow.
These behavioral differences may increase the relative contribution to
bioturbation by smaller worms.
P2.75 CHI, K. -J.*; CHANG, C. -T.; TSAI, F. -Y.; SHIH, M. -C.; National
Chung-Hsing University; [email protected]
Pterostigma regulates the dynamic properties of dragonfly wings
The pterostigma of insect wings, usually a pigmented spot, locates close to
the leading edge far out on the wing. Our measurements show that in
dragonfly, pterostigma accounts for merely 0.5% of the wing area, yet
weights for more than 2.5% of wing mass without the enframing vein. Such
concentration of mass suggests it may affect the dynamic properties of the
wing during flapping. Previous study suggests pterostigma an inertial
regulator of wing pitch to raise the gliding speed limit, at which self-excited
vibrations would otherwise occur without this mass. However, no empirical
evidence is provided to date. In this study, we examine the effects of
pterostigma on the dynamic characteristics of isolated dragonfly wings under
forced vibration. To quantify the deformation of the wing, the relative
positions of the base, nodus, and pterostigma of the wing were measured.
Our data reveal that the existence of pterostigma does change the wing's
oscillating distortion mode during flapping. After the pterostigma was
removed, the oscillating amplitude of wing deformation decreases, yet the
resulting fluctuation increases. These results suggest that pterostigma may
magnify the deformation of the wing, while stabilize its oscillation mode.
Furthermore, we find a phase difference occurred between the stabilized
mode and the driven flapping. This phase shift may have mechanical
consequences on the flight of dragonflies.
e212
P1.121 CHO, I.*; COVI, J.A; BADER, B.D; MYKLES, D.L; Colorado State
University; [email protected]
Expression of a Myostatin Transcript in Carcinus maenas: Response to
Ecdysteroid Levels
Myostain (Mstn) is a member of the TGF-beta superfamily, known for its role
as a negative regulator of muscle mass in mammals. Similarly for
crustacenas, Mstn is hypothesized to take part in a reversible atrophy of
muscle tissues during molting necessary for organismal growth. When
crustaceans molt, their appendage muscles need to atrophy in order for them
to pull through the small basi-ischial joints. We hypothesize that Mstn acts as
a link between molt-inducing ecdysteroid and calpain proteases, which
degrade muscle proteins. We previously identified a partial cDNA (175 bp) of
a Mstn-like transcript from Carcinus maenas that is highly conserved with
Mstn in land crab, Gecarcinus lateralis and lobster, Homarus americanus.
The partial sequence encodes a 58 amino acid sequence of the mature
peptide. Examination of Mstn expression is conducted by using real-time
RT-PCR. Mstn expression is assessed in various tissues from intermolt
animals. In addition, Mstn expression in skeletal muscles is examined to
assess its response to different levels of ecdysteroid at various molting
stages. Supported by NSF (IBN-0618203).
P3.79 CHOJNOWSKI, JL*; BRAUN, EL; Univ. of Florida; [email protected]
Candidate genes in a turtle with temperature-dependent sex
determination
Some turtles determine if the developing gonad will ultimately become an
ovary or a testis by their incubation temperature during specific stages during
embryological development, ultimately called temperature-dependent sex
determination (TSD). The red-eared slider turtle (Trachemys scripta)
produces males at low temperatures, females at high temperatures, and a
mixture at intermediate temperatures but the molecular pathway that
underlies gonad development through temperature is only recently being
studied. Candidate genes determined from a macroarray of the red-eared
slider were characterized for different temperatures and stages during gonad
development.
P3.199 CHU, K.H. *; TSANG , L.M.; LAI, J.C.Y.; AHYONG, S.; NG, P.K.L.;
Chinese Univ. of Hong Kong, China, National Univ. of Singapore, Singapore,
National Inst. of Water and Atmospheric Research, Wellington, New
Zealand, National Univ. of Singapore, Singapore; [email protected]
Molecular phylogeny of the true crabs (Crustacea: Decapoda:
Brachyura) with an estimation of divergence time for the major lineages
True crabs of the infraorder Brachyura represent one of the most diverse
groups of crustaceans with almost 7000 described species inhabiting
habitats from marine, freshwater to terrestrial. The relationships among the
brachyuran families are poorly understood due to the high morphological
diversity of the group. Using sequence data from three nuclear
protein-coding genes (glyceraldehyde-3-phosphate dehydrogenase,
sodium-potassium ATPase alpha-subunit and enolase), we attempt to
reconstruct a phylogeny of the Brachyura. Preliminary results based on more
than 50 species from over 20 families reveal that the basal Podotremata is
paraphyletic, with Raninidae more closely related to Eubrachyura than to the
other Podotremata. This is concordant with a previous analysis based on
18S rDNA sequences (Ahyong et al. 2007, Mol. Phylogenet. Evol. 45:576).
Within the Eubrachyura, the analysis supports the reciprocal monophyly of
the two subsections, Heterotremata and Thoracotremata. The close affinity
of some of the families is evident (e.g. Homolidae + Latreilliidae; Xanthidae +
Trapeziidae + Goneplacidae; Matutidae + Calappidae + Euryplacidae). The
results corroborate the new classification scheme proposed by Ng et al.
(2008, Raffles Bull. Zool. 17:1) to a certain extent (including most superfamily
groupings). However, most of the internodes supporting superfamilial
relationships remain poorly resolved, suggesting that further analyses will
need to be done using more genes and taxa. The divergence times for the
major lineages of Brachyura were estimated based on a Bayesian relaxed
molecular method. [This work was supported by a RGC CERG grant
(4419/04M) of HKSAR.]
P1.156 CHUNG, J. Sook*; SHI, Q.; University of Maryland Biotechnology
Institute, Baltimore; [email protected]
Trehalose 6-phosphate synthase genes of the blue crab, Callinectes
sapidus: the molecular structure, the expression, its enzyme activity
and relationship to hemolymph trehalose levels
Trehalose in ectoderms functions in energy metabolism and protection in
extreme environmental conditions. We structurally characterized trehalose
6-phosphate synthase (TPS) from hemocytes of the blue crab, Callinectes
sapidus. C. sapidus HemoTPS, like insect TPS, encodes both TPS and
trehalose phosphate phosphatase domains. Trehalose seems to be a major
sugar, as it shows higher level than glucose in hemocytes, hepatopancreas
and hemolymph. Increases in HemoTPS expression, TPS enzyme activity in
hemocytes, and hemolymph trehalose levels were determined 24 h after
lipopolysaccharide challenge. The TPS gene has a wide tissue distribution in
C. sapidus, suggesting multiple biosynthetic sites. A correlation between
TPS activity in hemocytes and hemolymph trehalose levels was found during
the molt cycle. Feeding and exercise showed immediate changes in this
sugar levels in hemolymph and hepatopancreas. The current study provides
the evidence of the presence of trehalose and TPS gene in hemocytes and
hepatopancrease of C. sapidus and implicates its functional roles in energy
metabolism and physiological adaptation.
e213
P1.83 CHURCHILL, Morgan M.*; CLEMENTZ, Mark; University of Wyoming;
[email protected]
Stable Isotope Analysis of Pinniped fossils from the San Diego
Formation (Late Pliocene, California)
Pinnipeds (seals and allies) represent an intermediate morphological and
ecological condition between fully aquatic marine and terrestrial mammals
and as such are an ideal group for study of the land-sea transition in
tetrapods. Morphology has been the primary focus of most studies of fossil
pinnipeds, but supplemental ecological information can be gained through
stable isotope analysis of fossil material. Tooth enamel is the preferred
material for stable isotope analysis because it is less prone to diagenetic
alteration. For studies of fossil pinnipeds, however, this presents a problem
as most taxa exhibit a reduction in enamel and in the number and size of
teeth. Here we assess the use of other biogenic materials (i.e., bone, dentin)
as potential archives of ecological information for pinnipeds. Bone and dentin
were sampled for carbon and oxygen stable isotope analysis from the Late
Pliocene San Diego Formation of southern California. Taxa sampled include
three species of fossil pinniped as well as coeval species of whales,
sirenians, fish and terrestrial mammals. Three types of criteria were defined
to assess the extent of diagenetic alteration in bone and dentin: 1)
comparison of phosphate oxygen values with carbonate oxygen values; 2)
similarity and degree of overlap in carbon values among ecologically distinct
taxa; and 3) how well the recorded isotope values fit predicted values for
Pliocene marine consumers. Once validated, these tools will then be applied
to study of earlier species representing the initial radiation of pinnipeds into
aquatic ecosystems.
P2.108 CLAESSENS, L.P.*; EDWARDS, S.V.; MARTINEZ, R.; KRZYZAK,
M.; ECKARDT, M.; LESLIE, G.; MARCUCCI, M.; NEABORE, S.; VRCEK, I.;
MOSS, S.; GRASSI, K.; College of the Holy Cross, Worcester, MA, Harvard
University, Cambridge, MA; [email protected]
Aves 3D: A new online resource for avian skeletal anatomy
Here we report the launch of a new National Science Foundation funded
online resource for avian skeletal anatomy, www.Aves3D.org, which will offer
three-dimensional models of a wide selection of skeletal elements of extant
and extinct birds. The Aves 3D database is produced through non-contact
laser scanning of skeletal material from, amongst others, the Harvard
Museum of Comparative Zoology and the Yale Peabody Museum of Natural
History. Database growth is fueled by undergraduate student research
projects, which involve a variety of functional and phylogenetic studies
supervised by both affiliated and external post-graduate students and
researchers. The online database will also serve as a digital archive for the
collections of contributing museums and allows for rapid global dissemination
of 3D digital data on common as well as rare and potentially fragile
specimens, in a format ready for a wide range of two and three-dimensional
computational analyses. The size of the database is currently limited, and
opportunities exist for initiating new student-based projects that will
contribute to database growth.
P3.36 CLAFLIN, SB; PIEN, CL; RANGEL, EN; UTZ, KE; WALTHER, HV;
WRIGHT, AN; ELLERBY, DJ*; Wellesley College; [email protected]
The effects of feeding on medicinal leech swimming performance
The locomotor system of sanguivorous leeches is presented with a unique
challenge: how to maintain mobility while coping with a greater than 500%
increase in body mass during feeding. A meal of this size is likely to disrupt
the function of the muscular hydrostat during swimming, reducing speed and
increasing predation risks. We quantified the effects of feeding to satiety on
swimming kinematics, and the time course of recovery of swimming
performance post-feeding in the medicinal leech Hirudo verbana. There was
a 5.07 fold increase in mass during feeding. Despite this, leeches were able
to swim immediately after feeding, reaching 27% of their pre-feeding speed.
Reduced speed was a consequence of a reduction in both swimming cycle
frequency and stride length to 69 and 42% of the pre-feeding values
respectively. Recovery of swimming ability was rapid, despite a prolonged
increase in body mass. 50% restoration of swimming speed was achieved in
approximately 1 hour while body mass was still 4.2 fold greater than before
feeding. Rapid mass and volume reduction immediately post-feeding, and
the properties of the obliquely striated swimming muscles appear to aid
recovery of swimming performance. Such features that aid post-feeding
recovery of mobility may have been important in the evolution of leech
sanguivory.
P3.148 CLAIRARDIN, S.G. *; GRIFFIN, A.M.; HOLGERSSON, M.C.N. ;
PAITZ, R.T. ; BOWDEN, R.M. ; Illinois St. Univ.; [email protected]
Nest temperatures and offspring phenotype in the painted turtle: Does
the magnitude of temperature fluctuations matter?
Maternal effects have been shown to impact offspring development. In
oviparous reptiles, studies utilizing constant laboratory incubations have
demonstrated that incubation temperatures can influence a suite of
phenotypic traits, including sex. Recent work has investigated how more
natural fluctuating temperatures influence offspring phenotype and shown
that temperature fluctuations can produce effects that differ from what would
be predicted under constant incubation conditions. This study aims to
investigate the potential for female painted turtles (Chrysemys picta) to use
vegetation cover as a predictor of temperature fluctuations within the nest.
This relationship was characterized for 16 natural nest sites using
temperature loggers to record nest temperatures and digital imagery to
quantify vegetation cover. To study phenotypic outcomes of temperature
fluctuations, eggs from eleven clutches were allocated to one of three
incubation regimes: constant temperature (27°C), four degree fluctuation
(27+/-4°C), and eight degree fluctuation (27+/-8°C). Data from natural nests
indicate that daily maximum temperature, daily mean temperature, and daily
temperature range, but not daily minimum temperature, were related to
overstory cover. In the lab, temperature fluctuations had a significant effect
on incubation duration, but not hatchling length, mass or plastron coloration.
Additional parameters of offspring phenotype will be measured including
righting time, immunocompetence (both cell-mediated and humoral), and
sex. The findings from this study indicate that overstory cover can affect nest
temperature fluctuations, which can ultimately influence offspring phenotype.
e214
P3.78 CLAREMONT, M.*; REID, D.G.; WILLIAMS, S.; Natural History
Museum, London and Imperial College London, Natural History Museum,
London; [email protected]
The evolution of coral feeding in the muricid gastropods
Muricid gastropods in the genus Drupella graze coral polyps and cause
damage to coral reefs during population outbreaks. Another well known
group of coral-feeding muricids are the Coralliophilinae, ecto- and
endoparasites that feed suctorially. The only other report of coral feeding
among muricids is of grazing on corals by Ergalatax margariticola. The
phylogenetic relationship between Drupella and Ergalatax is unknown, as is
their relationship with the Coralliophilinae. We wished to investigate whether
the current morphologically-based taxonomy correctly reflects three
independent origins of coral feeding behavior in this family. We used four
genes (28S, 16S, 12S and COI) to develop a molecular phylogeny of these
coral-feeding groups, and also included a range of other muricids. Our
results show a sister relationship between Drupella and Ergalatax, whereas
coralliophilines are a more distant monophyletic group. This suggests that
coral grazing only arose once in the Muricidae, and that parasitism of corals
appeared independently.
P2.26 CLARK, Mark*; BOONSTRA, Todd A.; REED, Wendy L.; North
Dakota State University, United States Fish and Wildlife Service;
[email protected]
Intraclutch variation in egg characteristics facilitating hatching
synchrony in Canada geese
In birds, females may regulate hatching synchrony in offspring by delaying
the onset of incubation. However in groups such as waterfowl, incubation
begins before the clutch is complete and the offspring hatch simultaneously,
indicating that embryonic development varies within the clutch. Mechanisms
facilitating the differential development of offspring within clutches of these
species have not been identified. We quantified embryonic metabolism,
conductance, shell characteristics and rapid yolk development in eggs from
complete clutches from a free-living population of Canada geese (Branta
canadensis). We found that metabolic rates are inherently higher for
embryos from eggs laid later in the clutch, rates of water loss are also higher
from eggs laid later in the clutch and shell porosity increases for eggs laid
later in the clutch. However, growth of yolk during the rapid yolk phase did
not differ among eggs in a clutch. We hypothesize that embryonic
development is regulated through the interaction between shell
characteristics and vascular development during the earliest stages of
incubation in waterfowl and related species.
P2.35 CLAUSEN, R.C.*; FIELDS, P.A.; TOMANEK, L.; Franklin and Marshall
College, Cal Poly San Luis Obispo; [email protected]
Temperature acclimation has a greater effect than heat shock on gill
protein expression patterns in two congeners of blue mussel (genus
Mytilus)
We used proteomic techniques to compare protein expression profiles of gill
tissue from two blue mussel congeners, Mytilus galloprovincialis (Mg) and M.
trossulus (Mt). The former is invasive along the coast of southern California,
and has replaced the latter, native congener there, perhaps due to greater
heat tolerance. After acclimating each species to 7 or 13C for 3 wk, we
exposed 6 treatment individuals to a heat shock (HS) of 32C for 1 h, followed
by 24 h of recovery at acclimation temperature (AT). Six control (no-HS)
individuals were sacrificed after acclimation. 2D gel electrophoresis was
performed on gill protein extracts, and protein expression profiles from 48
gels (6 replicates x 2 species x 2 AT x 2 treatments) were analyzed using
Delta2D software (Decodon). Over 1000 protein spots were found and
associated across all gels. Using a variety of analytical tools, including
ANOVA, hierarchical clustering, and principle components analysis, we
found that the two species differ in protein expression pattern, regardless of
AT. Further, within each species, there are significant differences in protein
expression between individuals acclimated to 7C compared to those
acclimated to13C. However, HS had a weaker effect than acclimation on
protein expression: Mg control and HS individuals showed little difference in
protein expression (i.e, these two groups did not cluster separately), while
protein expression profiles of Mt control and HS individuals showed
discernable clustering, but not of the magnitude found between 7C- and
13C-acclimated individuals. These data suggest that, in Mytilus congeners,
long-term acclimation may have a greater effect on tissue-wide protein
expression profiles than does HS, and that Mg is relatively less sensitive to
HS than Mt.
P1.73 CLEMENT, M.E.*; MUNOZ-GARCIA, A.; WILLIAMS, J.B.; Ohio State
University; [email protected]
Cutaneous water loss and lipids covalently bound to corneocytes in
house sparrows after acclimation to high and low humidity
Lipids of the stratum corneum (SC), the outer layer of the epidermis of birds
and mammals, provide a barrier to water vapor diffusion through the skin.
The SC of birds consists of flat dead cells, called corneocytes, and two lipid
compartments: an intercellular matrix and a monolayer of covalently bound
lipids (CBL) attached to the outer surface of corneocytes. We previously
found two classes of sphingolipids, ceramides and cerebrosides, covalently
bound to corneocytes in the SC of house sparrows and that these were
associated with cutaneous water loss (CWL). Desert house sparrows had a
lower ratio of covalently bound ceramides to cerebrosides than mesic birds,
which resulted in lower CWL rates. In this study, we collected adult and
nestling house sparrows from Ohio, acclimated them to either a high or low
humidity environment, and measured their rates of CWL. We then evaluated
the composition of the CBL of the SC using thin layer chromatography. CWL
was higher in nestlings than in adult house sparrows, and higher in
dry-acclimated than in humid-acclimated birds. Adults had a greater
proportion of covalently bound cerebrosides than nestlings. There was no
change in the composition of CBL between dry and humid acclimated birds
for either adults or nestlings. CWL decreased as the ratio of covalently bound
ceramides to cerebrosides decreased, consistent with our previous findings.
We also found that nestlings had greater variability in the
ceramide:cerebroside ratio than adults. These results suggest that the
composition of CBL in the SC changes with ontogeny but not in response to
acclimation.
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P3.124 CLEMENT, M.L.*; LEA, J.M.; PHAM, L.L.; SMITH, B.R.; SMITH,
D.C.; WAGNER, N.A.; SIMMONS, C.K.; BARTHELL, J.F.; Univ. of Central
Oklahoma; [email protected]
Hypatia of Alexandria: A Comparative Perspective on her Role in
History
Hypatia was a philosopher and mathematician during the 4th and 5th
centuries AD. Her role in history has been debated over time, but during the
last 15 years at least two books have addressed her role from differing
perspectives. We formed an interdisciplinary undergraduate seminar that
included a group composed of students from the sciences and mathematics
to compare two such perspectives. The first of these was the recent
contribution by M. A. B. Deakin entitled "Hypatia of Alexandria:
Mathematician and Martyr" (published in 2007). We also reviewed the work
by M. Dzielska entitled "Hypatia of Alexandria" (published in 1995) which is
directly referenced in Deakin's book. Our efforts focused on differences in
the way in which these authors appear to be influenced by their own
backgrounds (in mathematics and history, respectively) and the way in which
Hypatia's gender is relevant to the interpretation of her professional
contributions. Like a recent historical counterpart in the biological sciences,
Rosalind Franklin, we find that a degree of ambiguity is added to the
interpretation of Hypatia's work in accordance with the gender of the author.
In addition to developing a comparison of these studies of Hypatia, the
seminar provided at least three outcomes for student participants that
included 1) linking critical thinking exercises with the peer-review publication
process, 2) the opportunity to discuss history and nature of mathematics and
science, and 3) discussion of gender issues in relationship to careers in
mathematics and science.
P2.165 COLEMAN, A. T.*; WIBBELS, T.; ROOSENBURG, W.; MARION, K.;
Univ. of Alabama at Birmingham, Ohio Univ.; [email protected]
Geographic and Seasonal Variation of Reproductive Steroids in the
Diamondback Terrapin, Malaclemys terrapin
The diamondback terrapin, Malaclemys terrapin, is the only turtle in North
America that exclusively inhabits the brackish environments of bays and
estuaries. Studies have examined reproductive steroid levels in several turtle
species. This information has been crucial in elucidating certain physiological
and ecological aspects such as reproductive activity, stress levels, and sex
ratios. In the current study, testosterone and estrogen levels were measured
via radioimmunoassay (RIA) of blood samples from two populations of
diamondback terrapins. One is a declining population located in the salt
marshes of the Patuxent River region of Maryland. The other population is
located in the salt marshes surrounding Dauphin Island, Alabama, and has
experienced a significant decline from historic levels. Seasonal cycles of
reproductive steroids were examined. Adult females showed a gradual
decrease in testosterone over the nesting season, whereas, adult males
showed a gradual increase, peaking in late summer. Estrogen levels over the
nesting season will be reported. The results provide insight into the
endocrine physiology underlying the reproductive cycle in the terrapin. They
also provide information regarding the number of reproductively active
individuals in a population and represent better indicators of maturity than
age. A geographical comparison will be conducted to observe variation in
steroid levels between two populations that experience different climate
regimes. This information will be compared to those of marine and
freshwater turtles to better understand how the physiology of the
diamondback terrapin has evolved to adapt it to its unique marine niche.
P1.112 CONEJO, M.S.; HOFFMAN, G.G.*; ELLINGTON, W.R.; Florida State
Univ.; [email protected]
Cytoplasmic and Mitochondrial Arginine Kinase Isoforms in a
Choanoflagellate Protozoan
Arginine kinase (AK) catalyzes the reversible transfer of phosphate from
phosphoarginine to MgADP yielding MgATP and arginine. This enzyme plays
a central role in mitigating temporal and spatial ATP supply and demand
mismatches in cells displaying high and variable rates of ATP turnover. AK is
widely distributed in invertebrates and protochordates but is lacking in
craniates. A considerable base of molecular phylogenetic data and other
evidence support the view that choanoflagellate protozoans are a direct
sister group of the metazoans. The recently released genomic and EST
sequence database for the choanoflagellate Monosiga brevicollis contains
clear-cut evidence for at least three AK genes in this protozoan. We have
generated the cDNAs for two of these by RTPCR. One corresponds to a 394
residue AK with a calculated Mr of 42.57 kDa. This protein displays great
amino acid similarity to that of an AK from Aphrocallistes beatrix, a
hexactinellid sponge. On-line tools predicted that this AK is targeted to the
cytoplasm (cytAK). Expression of the cytAK in E. coli yielded highly active
soluble protein which was shown to be monomeric by size exclusion
chromatography. The other AK cDNA coded for a 421 residue protein with a
calculated Mr of 45.71 kDa. On-line tools indicated that this AK has an
N-terminal signal peptide. The majority of the tools predicted that this AK is
targeted to the mitochondrion suggesting that it is a true mitochondrial AK
(MiAK). Efforts are underway to express various MiAK constructs to assess
activity and quaternary structure. The present results support the view that
cytoplasmic and mitochondrial isoforms of AK are expressed in M.
brevicollis. These AKs very likely serve to mitigate reaction diffusion
constraints for energy transport between mitochondria in the cell body and
the long flagellum used in motility and food entrapment. (Supported by NSF
Grant IOS 0542236 to WRE).
P3.194 COON, Courtney A*; ADELMAN, Jim; LIEBL, Andrea L; MARTIN,
Lynn B; University of South Florida, Tampa, Princeton University;
[email protected]
Development of a simple assay to measure an integral
pro-inflammatory cytokine in songbird blood
Progress in ecological immunology has been hampered by a lack of
techniques providing strong inference into the mechanisms of disease
resistance. One important integrative immune response, the acute phase
response, involves adaptive alterations in body temperature, behavior and
circulating proteins all which serve to control or eliminate infection. The
cytokine IL-1beta is an important regulator of these proinflammatory
defenses in birds. In chickens, IL-1beta, primarily secreted by macrophages,
peaks in the blood 3-5 hours after injection with gram-negative bacterial
components (e.g. lipopolysaccharide, LPS). Recent advent of a polyclonal
antibody to chicken IL-1beta prompted us to test whether IL-1beta is
detectable using the same antibody via an enzyme-linked immunosorbent
assay (ELISA) in wild birds. If so, this commerically available antibody would
be a useful tool in avian ecological immunology. We found that IL-1beta from
wild house sparrows (Passer domesticus) was detectable 5h post-injection
with complete Freunds adjuvant (CFA), a substance that mimics a bacterial
infection without pathogen replication. Sparrows unchallenged with CFA
showed some antibody binding, but less than CFA-treated birds. Studies are
ongoing to i) validate that the antibody is binding IL-1beta and ii) develop a
standard that can be used to quantify inter-assay variation.
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P2.158 COOPER, Ann S.; University of KY; [email protected]
The Effects of Serotonin on Circadian Pattern and Behaviors in
Drosophila
It is established that adult Drosophila show circadian patterns that are
regulated by gene expression. Circadian cycles in adults can be induced and
set by exposure to light as early as the embryo stage without any circadian
patterns evident throughout the larval stages. Serotonin is known to have a
role in circadian patterns in adult Drosophila as well as many other species.
In this study, I addressed if the maintenance of the circadian pattern
throughout the larval stages can be modulated by altering the serotonin
expression levels in the larva. To approach this I exposed larvae, at various
stages, to a drug (p-CPA, 10mg/ml of food) that blocks the synthesis of
serotonin and then examined circadian patterns in adults. Adults were tested
on 12:12 light:dark cycle and then in continuous darkness. Adult and larval
locomotive behaviors were also examined for effects of p-CPA. In order to
measure circadian activity patterns I built a device to measure activity of
adults as individuals and groups. The results of feeding larvae p-CPA led to
a more distinctive circadian pattern, which was contrary to my hypothesis. As
adults, the p-CPA fed larvae showed a slower climbing response to light
(p<0.05, n=15, T-test). Associative learning assays in larvae showed that
p-CPA consumption improved learning. In summary, p-CPA fed larvae had
altered circadian patterns and behaviors as adults and larvae. (Funding was
provided by Kentucky Young Researchers Program at the University of
Kentucky (A.S.C.). Equipment was borrowed from Science Alliance which is
part of Partnership Institute for Math and Science Education Reform
(PIMSER) Univ. of KY.)
P2.149 COOPER, Robin L.*; BIERBOWER, Sonya M.; Univ of KY;
[email protected]
EFFECT OF EXERCISE AND ENVIRONMENT ON THE AUTONOMIC
RESPONSE IN CRAYFISH, PROCAMBARUS CLARKII
The effects of exercise have mainly been studied in vertebrates.
Unfortunately, less work has focused on the varied group of organisms,
invertebrates, which have more diverse collections of mechanisms to handle
physiological problems associated with locomotion. Crayfish are freshwater
crustaceans that reside mostly in water, exit for various reasons (i.e. food,
mates, burrowing) and do gas exchange by pulling water over the gills.
During periods of stress and physical exercise, crayfish exhibit typical fight or
flight responses since they show a sympathetic-like response which appears
to increase excitability to sustain physical activity. To meet the increase in
oxygen demand due to exercise, a response in both cardiac (heart rate, HR)
and respiratory (ventilation, VR) systems are required. Typically, both HR
and VR increase in an effort to increase oxygen delivery to target tissues,
especially muscles used for locomotion. Crayfish were exercised at normal
walking speeds for two, fifteen minute periods. In addition, crayfish were
exercised in two environments, aerated (normal) and nitrogen-saturated
(oxygen-deficient). The purpose of this study is to examine the effect of
intermittent periods of exercise in normal and low-oxygen environments on
the HR and VR of crayfish since very few studies focus on the whole animal
autonomic response. Preliminary results suggest increases in both HR/VR
during the first and second periods of exercise. Crayfish returned close to
baseline levels during the first recovery period in both environmental
conditions, whereas VR levels remained elevated in the nitrogen-saturated
environment during the second recovery period (after the second period of
exercise).
P2.104 COOPER, J.M.*; MARCOT, J.D.; Univ. of Illinois;
[email protected]
The evolutionary response of tooth-row morphology to habitat shifts in
artiodactyl mammals
Artiodactyls have experienced dramatic environmental changes throughout
their history, and their evolutionary response is recorded in a rich fossil
record. Previous studies specify numerous skeletal and dental correlates of
habitat use in living artiodactyls. Unfortunately, these traits often require fairly
complete skulls or elements not commonly preserved as fossils. Habitat
proxies from commonly preserved elements are required to better
understand the evolutionary response of artiodactyls to environmental
change. The ratio of the length of the premolar row to that of the molar row
has long been cited to distinguish open and closed environment artiodactyls.
Open-environment taxa are expected to have proportionally longer molar
rows to increase the grinding area for coarse fodder. We measured lower
teeth of 101 living artiodactyl species (242 individuals) with known habitats.
We performed discriminant function analysis to discriminate species from
open and closed environments. The simple ratio of the lengths of the
premolar and molar rows discriminated these groups nearly as well as more
complicated functions. Specifically, those with relatively shorter premolar
rows were found to inhabit open environments. By itself, this result does not
entail a strong evolutionary correlation between habitat and morphology. We
took a comparative approach to determine the evolutionary response, in
which we reconstructed both this ratio and habitat use on an existing
phylogeny of artiodactyls. We then compared the morphologic change that
accompanied evolutionary shifts in habitat use. Shifts to more closed
environments were typically accompanied by increases in the relative length
of their premolar rows, and the distribution of changes were significantly
different than those observed in shifts to more open environments.
P2.95 COPUS, J.M.*; REAVIS, R.H. ; SHUSTER, S.M.; Northern Arizona
University, Glendale Community College; [email protected]
The Tahitian Butterflyfish: A Bay Specialist and Territorial Omnivore
Butterflyfish (Family Chaetodontidae) are easily observed and well studied
members of coral-reef communities. Their behavior and ecology have been
cited to support models of speciation, territoriality and mating system theory.
However, most studies of butterflyfish have focused on obligate corallivores,
many of which mate monogamously. To further test these models, we
investigated the behavior and ecology of the endemic Tahitian butterflyfish,
Chaetodon trichrous. First, we determined the distribution of this fish around
Moorea Island, French Polynesia where it was a dominant Chaetodon
species in two bays of Moorea, but not seen in other habitats. We note that
the turbidity of these waters might explain the relatively drab coloration of C.
trichrous. Second, we tested the hypothesis that determinations of
territoriality may depend on the duration of observations made on
butterflyfish. We did not observe territoriality in our first (short) season of
observations. However, territorial behavior was confirmed after additional
observation. Finally, we observed C. trichrous fed broadly on planktonic and
benthic organisms, yet most adults were found in pairs. Moreover, females
fed on the benthos at higher rates than their male partners. This pattern of
feeding is common among monogamously paired fishes and suggests C.
trichrous may be monogamous. Our observations challenge the typical
models of Chaetodon mating systems which suggest that generalist
butterflyfish are not monogamous.
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P3.24 CORBETT, Alyssa H.; REED, J. Michael*; Tufts University;
[email protected]
Adam and Eve events: is successful population establishment from
small introductions a myth?
Although small populations are at high risk of extinction, there are regular
reports in the scientific literature of purported small, isolated, persistent
populations. One source of evidence of the viability of small populations
comes from the successful introduction of species to areas outside their
original range. We evaluated 23 purportedly successful establishments of
bird populations from deliberate translocation of very few (<30) individuals
that are reported in the scientific and secondary literature. We found that all
but 2 of the claims were unsubstantiated, primarily due to a lack of evidence
in original sources if the number of birds released and because of
supplemental individuals from earlier releases, releases in nearby regions,
and natural invasion. Our results support the general theory that small,
isolated populations are at high risk of extinction, and they suggest that
successful introductions using few individuals is actually rare. Because of the
potential misuse of ecological results in land use planning, in particular
assuming that small populations of vertebrates are viable, we suggest that a
high standard be set for asserting the viability of small, isolated populations.
P2.191 COSTANZO, J.P.*; LEE, R.E.; Miami Univ., Oxford, OH;
[email protected]
Urea Loading Enhances Freezing Survival and Postfreeze Recovery in a
Terrestrially-Hibernating Frog
We tested the hypothesis that urea, an osmolyte accumulated early in
hibernation, functions as a cryoprotectant in the freeze-tolerant wood frog,
Rana sylvatica. Relative to saline-treated, normouremic (10 mmol l-1) frogs,
individuals rendered hyperuremic (70 mmol l -1 ) by administration of an
aqueous urea solution exhibited significantly higher survival (100% versus
64%) following freezing at -4oC, a near-critical temperature. Hyperuremic
frogs also had lower plasma levels of intracellular proteins (lactate
dehydrogenase, creatine kinase, hemoglobin), which presumably escaped
from damaged cells, and more quickly recovered neurobehavioral functions
following thawing. Experimental freezing/thawing did not alter tissue urea
concentrations, but did elevate glucose levels in the blood and organs of all
frogs. When measured 24 h after thawing commenced, glucose
concentrations were markedly higher in urea-loaded frogs as compared to
saline-treated ones, possibly because elevated urea retarded glucose
clearance. Like other low-molecular-mass cryoprotectants, urea colligatively
reduces both the amount of ice forming within the body and the osmotic
dehydration of cells. In addition, by virtue of certain special properties, it may
bestow additional protection from freeze/thaw damage not afforded by
glucose. Supported by NSF grant IAB 0416750.
P1.29 COSTELLO, MJ*; BOXSHALL, GA; BOYKO, CB; HOEG, JT;
MARKHAM, J; APPLETANS, W; University of Auckland, Natural History
Museum, London, American Museum of Natural History, University of
Copenhagen, Arch Cape Marine Laboratory, Flanders Marine Institute;
[email protected]
Development of sustainable authoritative online species databases
The internet provides great opportunities for making scientific information
available to everybody everywhere. However, the range of information
available on the internet can be bewildering for users. Unlike conventional
print media, the authority behind the information is often unclear and there is
no peer-review, when they were created is often not stated, and they may
not be permanently maintained. Personal and institutional web pages may
suffer from limited expertise in web page design and information
management tools. A more ideal situation is where communities of experts
collectively create and maintain online content in a database with long-term
professional informatics support. The European Register of Marine Species
created an online inventory of (almost) all marine species in Europe in which
each taxon was edited by a peer-selected taxonomic expert. The editors
formed the Society for the Management of Electronic Biodiversity Data
(www.smebd.eu) to hold this IPR, and they collaborate with the Flanders
Marine Institute (Belgium) which acts as the technical manager and host
institution. This model has been expanded to create a World Register of
Marine Species, with several associated all-taxon regional (European,
Antarctic, North Atlantic) and all-environment (not just marine) global (e.g.
Porifera, Cumacea, Isopoda) species databases. All species names are
centralised in the common host database called Aphia. Editors are sought
and invited by SMEBD, and they can directly control the content by editing it
online. As the resource develops more editors are required to expand the
content and keep it current.
P1.122 COVI, JA*; MYKLES, DL; Colorado State Univ.;
[email protected]
Novel splicing variation of a myostatin-like gene in the decapod
crustacean, Gecarcinus lateralis
Alternative splicing of myostatin transcripts is exceedingly rare.
Myostatin-like genes have been identified in over one hundred species, but
variation in mRNA splicing is only reported to occur in chicken and trout. We
recently reported the identification of a myostatin-like gene in the blackback
land crab, Gecarcinus lateralis. Sequencing of PCR products generated by
rapid amplification of cDNA ends indicates that a single myostatin-like gene
in the land crab is the subject of extensive alternative splicing. Clear splicing
sites occur within the propeptide domain and 3 untranslated region. Both
intron retention and alternative donor/acceptor sites occur alone or in
combination to generate unique protein coding sequences that include a
complete mature peptide domain. The mature peptide sequence for land
crab is greater than 50% identical to that of mammalian myostatins and all
nine conserved cysteines are present. At least two splice variants produce
frame shifts that introduce premature stop codons in the propeptide domain.
Interestingly, alternative splicing in the chicken also produces a transcript
that encodes a truncated myostatin protein which lacks the mature peptide.
The differential expression of a truncated myostatin-like gene in two
disparate species suggests that the expression of a propeptide domain alone
could have functional significance. All transcripts exhibit a broad tissue
distribution, which suggests that the functional repertoire of the crustacean
myostatin is more diverse than that of the mammalian protein. The
predominant expression of myostatin-like transcripts in muscle tissue
suggests that this TGF-Β factor plays a role in regulating muscle physiology
in crustaceans. Supported by NSF IBN-0618203.
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P3.204 COX, Christian L. *; MAKOWSKY, Robert; ROELKE, Corey E.;
University of Texas at Arlington; [email protected]
Determining an optimal sequence divergence for phylogenetic analyses
Determining the appropriate gene for phylogeny reconstruction can be a
difficult process. Rapidly evolving genes tend to resolve recent relationships,
but suffer from alignment issues and increased homoplasy between distantly
related species. Conversely, slowly evolving genes work well for deeper
relationships, but lack sufficient variation to resolve recent relationships. We
attempt to determine the optimal level of sequence divergence for resolving
phylogenetic relationships at different levels using a known phylogeny. We
compiled the known phylogeny using well-supported relationships between
28 taxa within the phylum Chordata. Sequences of 7 mitochondrial protein
coding genes, 1 mitochondrial ribosomal gene, 2 nuclear protein coding
genes and 2 nuclear ribosomal genes were acquired for each taxa, and
Bayesian posterior probabilities for the correct nodes were calculated for
each gene. Across all genes, we found that 15-25% sequence divergence
was optimal for resolving the correct relationships. However, the ability of a
gene to resolve the correct relationship varied among gene type, with protein
coding genes correctly resolving relationships at very low divergence (less
than 15%), while ribosomal genes correctly resolved at greater sequence
divergence (20%). This information should be useful for selecting the right
gene to clarify intractable relationships, as well as minimizing both cost and
confounding information during project design.
P1.113 CRAWFORD, Sherine*; SADDLER, Claudette; CARROLL, Margaret,
A.; CATAPANE, Edward, J.; Medgar Evers College, Kingsborough
Community College; [email protected]
Effects of Chelating Agents, Calcium Disodium EDTA and
Diaminocyclohexanetetraacetic Acid, on Manganese Disruption of
Mitochondrial Respiration in Crassostrea virginica
Manganese (Mn) is a metal that at excessive levels in brain produces
Manganism which is similar to Parkinsons disease. The mechanism of action
of Mn is not completely understood and thought due to decreasing dopamine
levels in brain, effecting dopamine receptor activity and producing oxidative
stress to mitochondria. Previously, we showed Mn caused a dose dependent
decrease in mitochondrial 02 consumption, and p-aminosalicylic acid (PAS),
a drug which alleviate symptoms of Manganism, protected mitochondria
against Mn. PAS has anti-inflammatory and chelating abilities. The ability of
PAS to ameliorate symptoms of Manganism is thought to be related to its
chelating actions. To test this we studied effects of 2 chelating agents,
calcium disodium EDTA (EDTAca) and diaminocyclohexanetetraacetic acid
(DACH) on mitochondrial respiration the bivalve mollusc, Crassostrea
viginica, using a YSI Micro-Biological Oxygen Monitor with a micro-batch
chambers. Mn (5 µM - 5 mM) caused dose dependent decreases in
respiration. Pretreating mitochondria with 1 mM EDTAca blocked the effects
of Mn. Adding EDTAca to Mn treated mitochondria partially reversed the
effects of Mn. DACH was not effective in blocking or reversing actions of Mn,
and had its own inhibitory effects on respiration. The study shows EDTAca
was an effective blocker against the effects of Mn and may be beneficial in
reversing the negative effects of Mn accumulations. It also provides evidence
the ameliorating effects of PAS on Manganism is likely related to its chelating
actions. This work was supported by grants 2R25GM06003-05 of the Bridge
Program of NIGMS, 0516041071 of NYSDOE and 0622197 of the DUE
Program of NSF.
P3.34 CROFTS, S.C.*; GOSLINE, J.; Univ. of California, Irvine, Univ. of
British Columbia; [email protected]
An Investigation of the Mechanics of Ventilation and Sliming in
Pteraster tesselatus
While the body of Pteraster tesselatus is similar to other sea stars, it is also
covered by a supradorsal membrane. The resulting space, the nidamental
cavity, can inflate with water and deflate, allowing the sea star to actively
ventilate as well as release a defensive slime. Water is pulled into the
nidamental cavity through ambulacral pores, located at the junction between
the supradorsal membrane and the body wall. During ventilation, water is
expelled through an opening at the top of the supradorsal membrane, the
osculum. During sliming, water and mucus are expelled through spiracles in
the supradorsal membrane, rather than the osculum. The goal of this study
was to better understand this water pumping system and to identify
differences between the two behaviors. Change in volume and pressure
changes in the nidamental cavity were measured for different sized
individuals displaying both behaviors to quantify the water pumping
mechanism and identify any variations with size. Histological sections were
used to illustrate the morphology and mechanisms that allow for the change
in volume. Change in volume scales geometrically during ventilation,
whereas changes in volume during sliming appear to be allometric. Pressure
traces indicate that during the inflation phase of ventilation, pressure in the
nidamental cavity of both individuals measured was approximately -0.5 cm
H 2 O. During deflation there was a sharp peak of positive pressure,
approximately 2.5 cm H2O in the larger individual and approximately 1.5 cm
H2O in the smaller individual. During sliming, pressure traces became more
sinusoidal and a wider range of pressures was achieved; ranging from -1.5 to
2 cm H2O in the large individual and from -0.5 to approximately 1 cm H2O in
the smaller individual. Histology illustrates the muscles and connective tissue
that allows for these changes in pressure.
P3.3 CROSSLEY II, DA*; TATE, KB; EME, J; University of North Dakota,
University of California, Irvine; [email protected]
The impact of periodic dehydration stress on cardiovascular function in
the embryonic American alligator (Alligator mississippiensis)
Reptilian embryos are unique among amniotic vertebrates due to a virtual
absence of parental care following oviposition in most species and high
eggshell permeability in comparison to birds. This reproductive strategy
leaves the developing embryo subject to abiotic fluctuations in the
surrounding nest environment, such as reductions in gas conductance,
hypoxia and bouts of dehydration. These fluctuations can be recurrent during
long incubations (~70d for alligators), but their impact on the physiology of
developing reptiles is poorly understood. We studied the effects of periodic
dehydration events on embryonic alligators, including changes in
hemodynamic and blood composition parameters. Dehydration (net 15% loss
in egg mass across 60-80% of development) significantly (p<0.05) increased
hematocrit (34+2 vs 29+1% rbc), plasma osmotic concentration (361+9 vs
290+2 mmol*kg-1), yolk mass (18+1.5 vs 11.1+1.5 g) and ratio of heart to
body mass (5.0+0.3 vs 4.0 + 0.3 mg*g-1) compared to control embryos at
90% of development. Conversely, mean arterial pressure (1.2+0.2 vs 1.8+0.2
kPa) and embryonic mass 16.9+2.7 vs 32.9+2.7 g) were significantly
reduced by this stress compared to controls, with no significant difference in
embryonic stage. Our findings suggest that hydration state of the nest
environment can dramatically alter the physiology of developing American
alligator and may impact hatchling survival.
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P3.82 CUI, Jianzhou*; SHEN, Xueyan; KOCHER, Thomas D.; NAGAHAMA,
yoshitaka; University of Maryland; [email protected]
Forkhead gene family in medaka: a view on gene evolution and
embryonic expression
Using the genome sequence of the medaka, Oryzias latipes, we examined
the genomic complement of Fox genes in this organism to gain insight into
the evolution relationship and expression pattern of this gene family. Here we
identified 31 Fox genes by searching the Forkhead domain in medaka and
by PCR using primers designed from the result of the homology protein
alignment. All the medaka Fox genes are encoded in 18 subclasses as
follows: 5 Fox genes in subclass D; 3 Fox genes in subclass O; 2 Fox genes
in subclass A, B, E, F, G, I, N and P respectively; 1 Fox gene in subclass C,
H, J, K, M, Q and R respectively. Together with the Fox protein sequences of
human, chicken, frog, zebrafish, C. elegans, the phylogenetic relationship
was analyzed and compared. The genes structure, general features and 3
dimensional model of this Fox gene family were also discussed. In addition,
we examined the expression pattern of part of these genes in different adult
tissues and during embryo development in medaka by using quantitative
PCR and in situ hybridization, and the different spatial and temporal
expression profiles were found.
P1.124 CUPP, C.S.*; THOMPSON, K.E.; WEIGAND, K.L.; DEAROLF, J.L.;
Hendrix College, Conway, AR; [email protected]
Effects of betamethasone on the fetal rectus abdominus of the guinea
pig (Cavia porcellus)
Betamethasone is a corticosteroid often used to stimulate the development
of the lungs and initiate the production of pulmonary surfactant proteins of
infants. The intent of this project was to examine the effects of
betamethasone on the fetal rectus abdominus, an expiratory muscle of Cavia
porcellus. Corticosteroids accelerate tissue and organ development by
stimulating cells to stop dividing and start differentiating. Therefore, we
hypothesize that the expression of adult myosin heavy chain isoforms (fast:
IIA, IIX; slow: I) will be higher in the muscles of treated fetuses. Pregnant
guinea pigs were injected twice (0.5 mg/kg maternal weight), twenty-four
hours apart at 70% gestation with either betamethasone (treated) or sterile
water (control). Rectus abdominus samples were collected from each treated
and control fetus and prepared for SDS-polyacrylamide gel electrophoresis.
Aliquots of diluted myosin were electrophoresed for 24 hours at 275V and 8C
in a 7% acrylamide, 30% v/v glycerol separating gel. Gels were silver
stained, dried, and scanned into a computer. Scion Image was used to
quantify the proportions of the adult myosin heavy chain isoforms present
within the total myosin of each sample. If increased expression of adult
myosin isoforms occurs in the treated rectus abdominus, these muscles may
have contractile properties more similar to adult muscles than fetal rectus
abdominus muscles not exposed to prenatal steroids. Thus, when the
steroid-exposed fetuses are born, their breathing muscles will be better able
to deal with ventilatory challenges, such as infection, than the muscles of
unexposed neonates.
P3.88 CURTIS, Daniel L*; MCGAW, Iain J; Univ. Nevada, Las Vegas and
Bamfield Marine Sciences Centre; [email protected]
Digestive enzyme activity following feeding in low salinity in the blue
crab, Callinectes sapidus, and the Dungeness crab, Cancer magister
Digestive processes were examined in two crab species of differing
osmoregulatory ability during hyposaline exposure. The blue crab,
Callinectes sapidus, an efficient osmoregulator, displayed a summation of
the metabolic responses to low salinity and digestion which enabled gastric
processing (mechanical digestion) to continue unabated in low salinity. In
contrast, the Dungeness crab, Cancer magister, which is classed as a weak
osmoregulator displayed a decreased foregut contraction rate and an
increased time for clearance of digesta from the gut. This was associated
with a reduction in oxygen uptake when exposed to low salinity following
feeding. Since the costs associated with mechanical digestion are minimal, it
was hypothesized that the observed reduction in oxygen uptake may be the
result of modulation of more costly downstream processes such as
extracellular digestion and/or protein synthesis. The current study examined
changes in digestive enzyme activity (protease, chymotrypsin, and amylase)
in the hepatopancreas and gut fluid following feeding in low salinity in both a
weak (Cancer magister) and an efficient (Callinectes sapidus)
osmoregulator.
P3.188 DALTON, B.E.*; CARLETON, K.L.; MARSHALL, N.J.; CRONIN,
T.W.; University of Maryland, Baltimore County, University of Maryland,
College Park, University of Queensland; [email protected]
Male Cichlid Colors as Conspicuous Signals in Lake Malawi: The Fish's
Perspective
Cichlids in Lake Malawi have diversified rapidly, forming 500 to 1000 species
in approximately the last million years. Although the responsible speciation
mechanisms have yet to be firmly established, sexual selection is likely
involved. In the rock-dwelling clade (known as mbuna) male territoriality and
asymmetrical reproductive investment by mouthbrooding females are typical.
We hypothesize that if sexual selection is driving this diversification, males
will be more conspicuous than females. Indeed, closely related species differ
primarily in male nuptial coloration. Previous analyses of mbuna colors were
biased by human perception, however. Relative to human vision, mbuna
spectral sensitivity is shifted toward shorter wavelengths, including the UV.
Using a trichromatic color space model, we compared the conspicuousness
of male and female colors in nine species from the perspective of their own
visual systems. Conspicuousness of a color was evaluated as its distance in
color space from viewing backgrounds and from other colors on the same
fish. Male colors generally appeared more conspicuous than female colors in
most contexts. The blue and yellow colors typical of male mbuna contrasted
well with each other and with the backgrounds. Interestingly, in three species
female colors were more conspicuous than male colors in some viewing
contexts. We also revealed that effects of changing illumination due to water
depth can be countered by simple mechanisms of color constancy. These
results suggest that male mbuna colors could function as conspicuous
signals in a broad range of viewing conditions found in their habitat,
consistent with sexual selection as an important diversifying force.
e220
P1.2 DAVIS, J.M.*; PAPAJ, D.R.; Vassar College, University of Arizona;
[email protected]
A "Silver Ovipositor" Effect in the Walnut Fly, Rhagoletis juglandis.
Variation in the quality of habitats can result in variation in the physiological
and morphological traits of animals that develop within them. One potential
consequence of this is that the phenotypes of animals from high quality
habitats may provide them advantages when it comes to finding, defending
and/or utilizing similarly high quality habitats. Such "Silver Spoon" effects can
have important population consequences, but are rarely tested for. Here, we
test for a silver spoon effect in the walnut fly, Rhagoletis juglandis. Previous
research has demonstrated that the size of this fly is negatively influenced by
the number of larval competitors inhabiting the fruit in which it develops.
However, while unused fruit provides the best larval environment, it can be
difficult for females to penetrate unused walnut husks and females are
frequently observed re-using sites where eggs have previously been laid. We
tested whether larger females have an advantage in penetrating surfaces
with their ovipositors, thus providing them more opportunities to put their
offspring in unused fruit. We demonstrated that larger females are more able
to penetrate fruit models, and as a consequence lay more eggs per minute,
but fewer eggs per oviposition bout. Such a pattern indicates that some of
the variation in size and fecundity seen in this species may be
non-genetically inherited via a host-mediated maternal effect.
P1.169 DAVIS-BERG, E. C.; Columbia College Chicago;
[email protected]
Trail following and tentacle movements in the carnivorous rosy wolf
snail, Euglandina rosea
A variety of predatory gastropods, including Euglandina rosea were
introduced to Hawaii and other Pacific islands in a failed attempt to limit the
spread of the giant African land snail, Achatina fulica. Instead of consuming
Achatina fulica, E. rosea has been implicated in the decimation of many
species of endemic island snails. Euglandina rosea is native to the
southeastern United States, and can follow the mucous trails of its prey.
Although experiments have examined food choice, it is unknown if the ability
of E. rosea to follow mucous trails differs with prey snail species. This study
compared the ability of E. rosea to follow trails of two groups of gastropods:
those found within its local habitat (southeastern USA) and those found
outside its native range (Kansas). Each predator (n = 10) was tested against
a total of 24 individuals from eight species of gastropods (four species from
each area) and three individuals of each species. Unlike previous studies, E.
rosea followed trails in the direction that they were laid. The results of the
study indicate that prey gastropods from Florida and Kansas were followed
at almost identical frequencies by all ten predators tested. In addition, there
were differences in the predators' inter-tentacle angle between trail following
or not-following behaviors.
P2.132 DE MIRANDA JR., M.A.*; MAYBERRY, J.K.; PEARSON, L.E.;
KANATOUS, S.B.; Colorado State University, University of Alaska
Anchorage; [email protected]
Are Skeletal Muscle Adaptations to Diving in Weddell Seals
(Leptonychotes weddelli) a Response to Environmental Stimuli?
The purpose of this study was to determine whether the elevated aerobic
capacities in the skeletal muscle of Weddell seals (Leptonychotes weddelli)
is due to a genetic predisposition or a response to environmental conditions.
Cells were harvested from adult Weddell seal longissimus dorsi, the primary
swimming muscle. The primary cells were compared to a C 2 C 12 cell line
under normoxic (21% O2) and hypoxic (1% O2) conditions for six days, as the
myoblasts differentiated into mature myotubes. Myoglobin concentrations
and aerobic enzyme assays were used to measure skeletal muscle aerobic
capacity. We hypothesized that there would be a significant difference
between seal and mouse cells under hypoxic conditions. However, we found
no significant difference in citrate synthase activity or myoglobin
concentrations between the seal and mouse cells under normoxic or hypoxic
conditions. This indicates that the adaptations to diving in Weddell seal
skeletal muscle are not determined by a genetic predisposition, but are a
response to environmental stimuli.
P3.4 DEATON, L. E.; Univ. of Louisiana at Lafayette; [email protected]
FMRFamide and 5HT Increase IP3 levels in gastropod hearts
The hearts of molluscs are myogenic, but the cardiac output is modulated by
a variety of classical neurotransmitters and endogenous neuropeptides. Both
5-hydroxytryptamine (5HT) and the molluscan neuropeptide FMRFamide are
cardioexcitatory in gastropod molluscs. However, the mechanisms involved
in the effects of these agents on the ventricle are poorly understood. To
clarify the possible roles of cellular signaling pathways in the excitatory
effects of FMRFamide and 5HT on the hearts of molluscs, ventricles were
isolated from the marine snail Melongena corona and exposed to seawater
(SW) or to SW containing either 5HT or FMRFamide for 10 sec. The tissues
were then homogenized and assayed for cAMP and IP3 with commercial kits.
The cAMP content of controls was 0.38 pmol/mg wet wt. The cAMP level in
5HT (10-6 M) and FMRFamide (10-6 M)-treated tissues was, respectively,
0.42 and 0.47 pmol/mg. Ventricles treated with forskolin (10-5 M) had a cAMP
level of 0.31 pmol/mg. Control ventricles contained 0.13 pmol/mg IP3. The
level of IP3 was 0.32 pmol/mg in 5HT-treated tissues and 0.55 pmol/mg in
FMRFamide-treated hearts. In addition, phorbol esters caused positive
inotropy similar to the effects of 5HT and FMRFamide in isolated hearts.
Neither forskolin nor cholera toxin had any effect on the mechanical activity
of isolated hearts. These results suggest that the excitation of gastropod
hearts by 5HT and FMRFamide involves the activation of the phosphoinositol
phosphate cellular signaling pathway, but not the cAMP second messenger
pathway.
e221
P1.89 DECONINCK, A.; PERNET, B.*; California State University, Long
Beach; [email protected]
Molecular markers for studying the distributions of the intertidal ghost
shrimp Neotrypaea californiensis and N. gigas
The vigorous burrowing activities of thalassinidean shrimp have such
dramatic effects on their soft sediment habitats that these animals have
sometimes been considered both ecosystem engineers and keystone
species. Because they are such strong interactors, basic information about
their life histories and population dynamics is needed to effectively manage
the habitats in which they live. These data, however, can only be obtained if
the shrimp can be accurately identified. On the west coast of the United
States, two species of burrowing intertidal shrimp in the genus Neotrypaea,
N. californiensis and N. gigas, are currently recognized (a third species, N.
biffari, does not burrow in soft sediments). The two burrowing species are not
easily differentiated morphologically except as adult males that bear a
master claw (which is often lost in collection), which has led to uncertainty
about their distributions. Here we describe and validate (using mtDNA data)
allozyme markers that can be scored rapidly and inexpensively for the
identification of these species. Surveys using these markers reveal that both
species coexist at most sites surveyed in southern California, with some sites
dominated by one or the other, but that N. californiensis is heavily dominant
to the north of Pt. Conception. We also report on morphological analyses
aimed at identifying characters useful for differentiating male, female and
juvenile ghost shrimp on the west coast of the US.
P3.64 DEMES, B.*; CARLSON, K.J.; Stony Brook University, New York
College of Osteopathic MedicineBending regimes of capuchin limb bones ;
[email protected]
Bending regimes of capuchin limb bones
Capuchin monkeys, like many other primates, have a highly versatile
locomotor repertoire. We investigated how locomotor versatility influences
the loading regimes of distal limb bones by documenting substrate reaction
forces (SRF) and 3D limb postures for capuchins moving on a flat substrate
(terrestrial), on an elevated pole (arboreal), and performing turns. The SRF
vector forms discrepant angles with the forearm and leg, indicating that they
are loaded in bending. The bending axes are not in principal anatomical
planes but at oblique angles, and frontal plane bending is a major component
of the overall bending regime. The bending moments are higher for the leg
than for the forearm. The discrepancy angles between the limb segments
and the SRF vectors are more variable in simulated arboreal locomotion than
in overground locomotion. This confirms the notion that arboreal locomotion
is associated with greater variation in long bone loading than terrestrial
locomotion. Directional changes of about 30 degrees are also associated
with discrepancy angles that vary in orientation. Even at the moderate level
of locomotor variation simulated in the lab, bending regimes were found to be
variable. Most primate long bone shafts do not have highly biased cross
sections that preferentially reinforce one plane, and are therefore well-suited
to withstand variable bending regimes. Supported by NSF BCS 0548892
P2.179 DESCAMPS, E*; VLEMINCKX, K; ADRIAENS, D; Ghent University,
Belgium, Flanders Flanders Interuniversity Institute for Biotechnology,
Belgium; [email protected]
Inhibition of the canonical Wnt signaling pathway during craniofacial
development: impact on the craniofacial phenotype of Xenopus
tadpoles
The head is anatomically the most complex part of the body. Given the
complexity of the craniofacial structures, many genes and embryonic tissue
sources are known to be involved in their ontogeny. Among other processes,
Wnt proteins are implicated in the induction and differentiation of neural crest
cells. These cells give rise to most of the craniofacial skeleton and to the
peripheral nervous system. As such, many craniofacial defects may originate
from abnormal regulation of Wnt signals. We want to examine the
implications of the postembryonic Wnt activity in the Xenopus head.
Therefore, we tested to what degree inducibly inactivating the canonical Wnt
signaling pathway during early development results in skeletal deformations
of the cartilaginous skull. Additionally, relations between abnormal
development of the central nervous system and the architecture of the
cartilaginous brain-case are studied. Our focus lies on two particular aspects:
the macro-anatomy of the brain and the craniofacial skeleton. Comparison of
the head morphology and histology between wild-type and transgenic
tadpoles allows us to investigate and describe the variation of the
craniofacial structures, as well as the brain anatomy. Transgenic stage 40
tadpoles were exposed to dexamethasone, activating an inducible
Wnt-inhibiting chimeric transgene, and fixed at stage 46. Serial histological
sectioning of the craniofacial region was performed. Detailed anatomical 3D
analysis of the craniofacial region in the wild-type and the transgenic model
organism at stage 46 were carried out, and compared to the wild-type stage
40 phenotype. We aim to find out what modifications are linked to
inactivating the Wnt signaling pathway, and to what degree the observed
phenotypes reflect a constancy.
P1.91 DEWAR, E.W.; Suffolk Univ.; [email protected]
Durophagivores vs. mixed feeders: niche differentiation using
stereoscopic dental microwear
Because dental enamel preserves a record of foods recently chewed, the
microwear of teeth has long been used to differentiate diets in living and
extinct groups of mammals. For this work, I used a stereoscopic
low-magnification method to observe enamel use-wear features of 92
species of Paleogene mammals. Most of the species sampled were from the
White River Group of the American Great Plains, which are well-studied
assemblages that span the Eocene-Oligocene transition. I found previously
that despite substantial climatic change during the Eocene-Oligocene
transition, the mammals known from the White River Chronofauna
overlapped substantially in use wear when sorted into biostratigraphic zones.
This work describes a distinct group of "durophagivores" within the ungulates
that was recognized based on their differences in use wear with the common
browsers and grazers of the time period. The durophagivores or rooters
accumulated fewer but heavier scratches and many more pits than seen in
more mixed-feeding species. In addition to the durophagivores present in the
White River Chronofauna (particularly entelodonts and anthracotheres), I
found evidence for abrasive diets in early members of several artiodactyl
families and archaic groups such as "condylarths" and tillodonts. Similar
evidence of abrasive parts of the diet is seen when comparing the use wear
of carnivorans that chew bones as opposed to meat specialists that avoid it
in their diets. In this case, skeletal elements rather than silica-based grit are
likely to have caused their heavy wear. The likely source of of dietary
abrasion is delimited by considering morphological differences among
species' teeth and the foods that they were likely adapted to comminute.
e222
P3.165 DICKENS, M. J.*; ROMERO, L. M.; Tufts University;
[email protected]
Transient disruption in corticosterone negative feedback resulting from
captivity
Maintaining wild animals in captivity has long been used for conservation and
research. While the potential for causing chronic stress has been widely
suggested, how captivity affects the underlying stress physiology is poorly
understood. In our study, we used a model species, chukar (Alectoris
chukar) to assess the effects throughout ten days of captivity on the
corticosterone (CORT) secretory pathway: the
Hypothalamic-pituitary-adrenal (HPA) axis. Specifically, we were interested
in the changes in negative feedback sensitivity along the axis since many
studies have linked chronic stress to a disruption in CORT secretion
feedback. To test changes in negative feedback we used two approaches. In
one experiment, we restrained the individuals for 15 minutes in a cloth bag
and then injected, intramuscularly, a synthetic glucocorticoid,
dexamethasone (DEX), to stimulate negative feedback and sampled for
CORT 30 minutes after the injection. In the second experiment, we
restrained individuals for 30 minutes and then returned them to the aviary,
thus ceasing the stressor, and allowed 30 minutes without disruption before
sampling for CORT. In both experiments the strength of negative feedback
(as indicated by the decrease in CORT over the 30 minutes) decreased by
day 5 but was regained by day 9. We concluded that introduction into
captivity shifted the chukar into a state of chronic stress; however, the
observed alterations to negative feedback began to recover by day 9. Also,
since the patterns of disrupted negative feedback across the days of
captivity, as determined by DEX stimulation, corresponded to the pattern
seen while using stressor cessation (natural negative feedback), these data
demonstrate the validity of using the DEX suppression test as an indication
of negative feedback disruption.
P2.196A DILLY, G.F.*; GIRGUIS, P.R.; Harvard University;
[email protected]
Exploring the Boundaries of Metazoan Thermotolerance at
Hydrothermal Vents: Respiration and Protein Expression of
Paralvinellid Worms
Eukaryotic thermotolerance is pushed to its limits at one of the most extreme
ecosystems on the planet, deep-sea hydrothermal vents. Temperatures
around vent sulfides (or chimneys) range from 2C to well over 300C. This
wide thermal regime has given rise to some of the most thermally tolerant
organisms on earth including the annelid Paralvinella sulfincola. These
worms are found at vents on the Juan de Fuca Ridge, in 2200m water
depths off the coast of Washington, USA. Paralvinellids are amenable to
recovery and shipboard experimentation and can withstand prolonged
exposure to temperatures between 5C and 55C, one of the largest thermal
ranges known.
P2.192 DOHERTY, AH*; VINYARD, CJ; NEOUCOM; [email protected]
A cross-sectional analysis comparing woodchuck (Marmota monax)
skeletons before and after hibernation
Long periods of inactivity in most mammals result in significant bone loss that
may not be completely recoverable during an individuals lifetime regardless
of changes in activity. Prolonged inactivity is the norm for hibernating
animals, but it is unknown whether they suffer from adverse bone health after
hibernation that affects their ultimate survival. We examined woodchuck
(Marmota monax) skeletons using computed tomography (CT) to test the
hypothesis that bone cross-sectional area and density is lost during
hibernation due to prolonged inactivity. Museum specimens were grouped
into pre- and post-hibernation samples based on the collection date,
approximating time of death, from museum records. CT scans were taken at
the diaphyses and distal metaphyses of the tibia and femur and through the
midline of the fourth mandibular premolar. We analyzed scans using Image J
and XCT540 to measure bone cross-sectional area, density, and
biomechanical indices of pre- and post-hibernation specimens and compared
the two groups using ANOVAs. Initial results from the size-adjusted
diaphyses of the two long bones suggest that there is no significant loss of
bone during hibernation. In fact, indications of bone formation were evident in
that absolute values of femoral cortical diaphyseal area (p=0.014), femoral
cortical density (p=0.047), and tibial cortical density (p=0.009) were
significantly larger in the post-hibernation sample. Given that our sample
included a percentage of yearlings, we speculate this absolute increase in
bone parameters relates to continued growth during hibernation. While these
results suggest woodchucks have derived mechanisms for maintaining bone
health during hibernation, longitudinal studies are underway to identify which
aspects of bone metabolism regulate the skeleton in hibernating
woodchucks.
P1.125 DORNHOFFER, T.M.*; WEIGAND, K.L.; DEAROLF, J.L.; Hendrix
College, Conway, AR; [email protected]
Does fetal betamethasone exposure increase the potential for fatigue in
the scalenus muscle of guinea pigs (Cavia porcellus)?
Betamethasone is a corticosteroid, a group of drugs often used to reduce
mortality in premature infants. Its effects on breathing muscle development,
however, are not well known. Studies have shown that similar corticosteroids
significantly reduce the oxidative capacities of adult diaphragm muscle.
Based on these studies, we hypothesize that betamethasone will significantly
reduce the oxidative capacity of the scalenus. This reduction could have
significant ramifications for a fetus exposed to such steroids, reducing the
fatigue capacity of the ventilatory muscles. A secondary goal of this project
was to see if differences in oxidative capacity can be used to subtype the
fast-twitch fibers in the fetal muscles. Guinea pigs were injected with
betamethasone (0.5 mg/kg maternal weight) or sterile water twice a week (24
hours apart) for three weeks. After a gestation period of 59 days, scalenus
samples were obtained from treated and control fetuses and prepared for
muscle histochemistry. Sections of the muscle samples were stained for their
NADH-tetrazolium reductase activities to quantify oxidative capacity and
counterstained with eosin to highlight fiber margins. Additional serial sections
were stained with slow antibodies to locate slow fibers within the sections.
Images of stained sections were captured and analyzed using Scion Image,
and the mean staining density of a representative sample of fibers was
measured. At the time of writing, data collection is insufficient to determine
the effects of betamethasone on oxidative capacity. Preliminary data indicate
the presence of multiple peaks within a mean density plot of staining
densities of the fast-twitch fibers, which suggests that oxidative capacity can
be used to subtype these fibers.
Our experiments utilize live worms in flow-through chambers at in situ
pressure and chemistry that replicate vent conditions. Coupling
high-pressure respirometry with tandem mass spectrometry, this work
examines oxygen consumption rates and differential protein expression of P.
sulfincola and P. palmiformis, maintained under two thermal regimes (30 and
53C, and 12 and 35C respectively). Our data suggest that P. sulfincola
exposed to 53C exhibit an up-regulation of proteins involved in maintaining
cellular structure and a down-regulation of enzymes associated with energy
metabolism. Surprisingly, P. sulfincola exhibited high concentrations of
HSP70 in both treatments. We suggest that the continual production of
HSPs, as well as an increased synthesis of proteins that confer structural
stability allow P. sulfincola to survive exposure to temperatures greater than
50C. These data provide the first insights into the biochemical factors that
enable an organism to exist at the edge of eukaryotic thermotolerance.
e223
P2.182 DOUGLASS, JK*; TOBIN, WF; WCISLO, WT; Smithsonian Tropical
Res. Inst., Panama, Univ. of California, Santa Cruz; [email protected]
A Portable Microvolumeter for Studies of Invertebrate Brain-body
Scaling
We describe an inexpensive device for rapidly measuring volumes of small
biological structures, and its application to brain-body scaling in insects.
Invertebrates, with bodies a fraction as big as a small rodent's brain, often
rival the behavioral sophistication of mammals. Does the size (volume or
mass) of the nervous system impose fundamental constraints on behavioral
complexity, or have small animals evolved specializations that squeeze extra
computational power from tiny brains? A basic step toward addressing such
questions is to evaluate how whole brains and nervous systems scale with
body size. This has been extensively studied among vertebrates, but
neglected in invertebrates despite their much greater diversity. The paucity of
invertebrate data may in part reflect technical problems. Some brain-body
scaling data have been provided from histological studies, but reconstructing
volumes from sections is time-consuming, and the role of shrinkage artifacts
is uncertain. Our method avoids these drawbacks, using the principle of fluid
displacement to directly measure intact volumes. This is straightforward for
large volumes; smaller volumes are measured by carefully controlling fluid
levels with a micrometer syringe, matching objects to an appropriate
container size, accounting for evaporation, and exploiting fluid surface
tension and optical properties. Calibrations using a series of spherical test
ball sizes yield standard errors of +/- 5% down to 0.26 microliters; planned
refinements may extend comparable accuracy to smaller volumes.
Preliminary data from insects will be presented. The device is easily portable
to any field station with a dissecting microscope, stable platform, walls and a
roof, and the method is applicable to studies of a variety of biologically
interesting volumes.
P1.157 DREBITKO, Heather*; MORRIS, Robert; VATNICK, Itzick;
BRODKIN, Marc; Widener University; [email protected]
A Microarry Investigation of Genes Involved in Pollutant-mediated
Immunosuppression in Rana pipiens
Our research examines the effect of environmental pollutants on the
amphibian immune response. We have documented the immunosuppressive
effect of exposure to a moderate acidic pH (5.5) and the herbicide atrazine
on the inflammatory response of Rana pipiens. Specifically, we have shown
that both environmental pollutants suppress an experimentally-induced
peritoneal inflammatory response with a concomitant decrease in the
phagocytic activity of these recruited cells. Work presented here examines
the genetic changes occurring in acid-exposed adult Rana pipiens. We make
use of microarray technology to elucidate the genetic mechanisms involved
in pollutant-mediated immunosuppression. This technology represents an
excellent tool for examination of the complex cascades of the immune
response. Our study is limited by the lack of a suitable frog microarray
necessitating our use of a mouse microarray supplied through the Genome
Consortium for Active Learning (GCAT). In spite of this limitation we have
identified 31 genes exhibiting significant suppression, and a much larger
number of genes under less stringent condition of analysis, in acid-exposed
Rana pipiens. We are currently identifying these genes and their role in
immunosuppression that results from exposure of Rana pipiens to an acidic
pH.
P1.77 DUNCAN, C.A.*; JOHN-ALDER, H.B.; Rutgers Univ., New Brunswick;
[email protected]
Food Restriction Inhibits Growth Rate but Not Expression of Hepatic
IGF-I Message in Yarrows Spiny Lizard, Sceloporus jarrovii
The growth hormone/insulin-like growth factor-I axis is the central growth
regulatory axis in vertebrates, and nutrition is a major regulator of this axis. In
particular, the growth-promoting actions of GH are primarily mediated by
IGF-I. To determine the effects of nutrition on growth and the expression of
hepatic IGF-I message, captive male and female Sceloporus jarrovii were fed
diets of high food (3 crickets/d) and low food (1 cricket/d) availabilities for a
10-week treatment period. We predicted that food restriction would inhibit
growth and decrease the expression of hepatic IGF-I message in comparison
to high food availability. In the present study, food restriction inhibited growth
rate by about 50% in snout-vent length (SVL) and decreased mass of fat
bodies relative to high food availability. At the conclusion of the treatment
period, levels of plasma corticosterone (B) did not differ between treatment
groups, but the low-food group had higher production of basal B in
adrenocortical cells relative to the high-food group. Taken together, these
data demonstrate that food restriction did not chronically stress animals in
either treatment group. Furthermore, food restriction did not decrease the
relative expression of hepatic IGF-I message compared to high food
availability. Although differing levels of available nutrition led to dramatic
differences in growth between treatment groups, these results indicate that
the food regimen in this study was not sufficient to elicit a response that
would negatively regulate the GH/IGF-I axis at the level of hepatic IGF-I
message. Future studies will need to be designed such that the nutritional
treatment produces a negative energy balance. Supported by NSF (IBN
0135167 to HBJ-A).
P2.32 DURICA, DS*; JOHNSON, JB; DAS, S; LEE, K; HOPKINS, PM; Univ.
of Oklahoma; [email protected]
Structure and Expression of the Uca pugilator E75 Nuclear Receptor: a
Primary Ecdysteroid Response Gene
The E75 nuclear receptor gene was one of the first gene loci shown to be
transcriptionally up-regulated in response to ecdysteroid exposure. It has
been cloned in a number of insect species, where several isoforms, arising
through differential splicing and alternative promoter usage, have been
characterized. Among crustaceans, E75 homologs have been identified in
the shrimp Metapenaeus ensus, where multiple isoforms were identified, and
in the brachyuran crab, Gecarcinus lateralis, where a single isoform was
discovered. Using specific primers, we first isolated a 431 nucleotide
segment of the Uca pugilator E75 homolog using RT-PCR, encompassing
the conserved ligand binding domain and a portion of the hinge region. This
subclone was then used to screen a late proecdysial oligo-dT primed cDNA
library derived from limb bud mRNA. Four independent isolates were
recovered from library screenings; overlaps within these clones revealed a
single open reading frame of 797 amino acids. The Uca E75 homolog shows
94% nucleotide identity and a probable 99% amino acid sequence identity to
the Gecarcinus sequence, using Clustal alignments to other E75 genes and
EST sequences from insects and other crustaceans. Nucleotide sequence
conservation (>75% identity) also extends into the non-coding regions. The
E75 gene is expressed during embryogenesis and early larval development,
and during blastemal organization and hypertrophic growth of the
regenerating limb bud. Hormonal induction experiments of newly hatched
zoal larvae, using three endogenous crustacean ecdysteroids (ponasterone
A, ecdysone and 20-hydroxyecdysone) show a dose-dependent increase in
transcript accumulation following a 3 hour exposure to ponasterone A,
indicating that the E75 transcription unit is an ecdysteroid primary response
gene in crustaceans.
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P2.83 DWYER, Laurel A*; LANDBERG, Tobias; University of Connecticut;
[email protected]
Predator induced plasticity in spotted salamanders
During metamorphosis, amphibians may be particularly vulnerable because
they lack the specialized anti-predator responses of either aquatic larvae or
terrestrial adults. This project was designed to study predator-induced
plasticity in the spotted salamander, Ambystoma maculatum, at
metamorphosis to determine if individuals could reduce their predation risk
by changing their behaviors in lethal predation trials or by increasing the rate
of metamorphosis. Salamanders were raised in two treatments: with a fish
predator (genus Lepomis) on the other side of a divided tank, or without fish
cues. Surprisingly, during the larval stage the predator treatment group
experienced extremely high mortality rates which raised new questions about
the indirect effects of predators on development. Behavioral trials revealed
that predator-treatment animals ate less than those not exposed to fish and
had lower body mass for their developmental stage. This suggests that
reduced feeding rates lead to decreased body condition which, in turn,
increases mortality. Exposing predator-naive animals to predator cues
induced an immediate drop in feeding rates. However, predator-exposed
animals placed into predator-free water did not increase their feeding rates in
the same time frame. Thus fish predators have both an immediately inducible
as well as a lasting effect on salamander feeding rates. The duration and
onset of metamorphosis are still being studied to determine if there are
differences between treatments.
P1.5 ECHEVERRY-GALVIS, M.A.; Princeton University;
[email protected]
Breeding and molt in Neotropical bird communities
The temporal regulation of key events, such as molt and reproduction in the
life cycle of individual birds requires highly sensitive internal mechanisms
that can respond to variations in environmental conditions. For most tropical
high-altitude species little information is available regarding the annual
regulation of molt and reproduction. I surveyed breeding and molting periods
of various bird species found at 2700-2900 meters altitude in four patches of
cloud mountain forest of different sizes in Colombia. I used laparotomies to
determine breeding condition, and scored molt in flight and contour feathers
in 775 individuals. Weather conditions and resource availability were
monitored. Breeding occurred on a seasonal basis with individuals fully
regressing their gonads at different times of year. In the two big areas (larger
than 800ha) breeding seemed to be bimodal with a hiatus of about 4 months,
while in the small areas (smaller than 15ha) breeding was unimodal.
Breeding periods were correlated with increased resource abundance
(insects and flowers) as well as photoperiodic in different areas. Molt was not
restricted to the post-breeding period in any area, overlapping with enlarged
gonads. Like breeding, molt occurred earlier in males than in females.
Molting periods were correlated with ambient temperature, photoperiod and
insect abundance. Molt/breeding overlap was more common in the small
compared to the big areas, and was present in 46% of all species. These
data raise questions about the ecological factors and the physiological
mechanisms that allow these two events to occur simultaneously in certain
species. Current studies are investigating the hormonal profiles of individuals
that show molt/breeding overlap to understand the proximate factors that are
at the basis of this phenomenon among Neotropical cloud mountain birds.
P3.42 ELDERBROCK, Emily K.*; KERN, Michael D. ; LYNN, Sharon E. ; The
College of Wooster; [email protected]
Feather Growth Bars Do Not Predict Nutritional Status in Nestling
Eastern Bluebirds
Ptilochronology is a method of determining nutritional status in adult birds by
measuring the width of growth bars on their feathers. The width of a pair of
adjacent light and dark growth bars represents the amount of growth during a
24-hour time period. Thus, ptilochronology assists in providing a complete
record of the daily nutrition of a bird during the growth of the feather.
Ptilochronology has been validated in the induced feathers of many species
of adult birds, but a recent study suggests that this technique may not be
applicable to first developed wing feathers in nestlings. To further investigate
this finding, we performed an experiment with Eastern Bluebird (Sialia sialis)
nestlings in which we examined the relationship between the width of the
feather growth bars on two developing wing feathers of chicks and other
measures of their growth, including wing length, tarsus length, and body
mass. We predicted that if the method of ptilochronology is applicable to
nestling bluebirds, a significant correlation between daily growth and the
width of the growth bars on these feathers would exist. However, we found
no correlation between the measures of growth and the width of the feather
bars. Furthermore the bars were found to be approximately half the width
that was expected for a 24-hour period based on daily growth rates of the
feathers themselves. Thus, our data support previous findings in nestlings of
other species, suggesting that ptilochronology may not be a reliable method
in determining nutritional status in nestlings.
P1.128 ELLIS, I.R.*; KEMPF, S.C.; Auburn University, Alabama;
[email protected]
Histological and SCP-like Neuropeptide Investigations in the Larval
Oyster Crassostrea virginica
The Eastern oyster Crassostrea virginica is an important species within
estuarine ecosystems where populations have recently become
compromised. In addition, oyster aquaculture has become a rapidly growing
industry. To facilitate restoration and aid in aquaculture practices, it is
important to understand neural morphology and how it affects larval
behaviors. Although a few immunohistochemical studies have been
conducted, the literature pertaining to bivalve larval central nervous systems
still lacks a detailed histological analysis. Also, there has been no
documentation to date of the location and possible function of small
cardioactive peptides (SCPs), a common neuropeptide in molluscan larvae.
This study provides a histological analysis and insight pertaining to the
development of the larval central nervous system of C. virginica. Larvae at
the D-hinge, umbo, and pediveliger life stages were purchased from the
Dauphin Island oyster hatchery. Each larval stage was either 1) fixed and
embedded in Epon 812 plastic, and then sectioned using an ultramictome for
histological analysis, or 2) fixed and then immunohistochemically labeled to
visualize SCP-like neuropeptides using a laser-scanning, confocal
microscope. Progressive development of the central nervous system of C.
virginica, along with investigations of the presence and location of SCP-like
neuropeptides were examined.
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P3.94 ELLISON, JA*; TURMELLE, AS; MENDONCA, MT; MCCRACKEN,
GF; RUPPRECHT, CE; Auburn Univ., Univ. of Tennessee, Centers for
Disease Control and Prevention ; [email protected]
Interleukin 2 expression in the big brown bat Eptesicus fuscus
Bats have recently been recognized as hosts and vectors to a variety of
emerging pathogens but very little is known about their immune system. As
part of a larger study to investigate susceptibility of big brown bats (Eptesicus
fuscus) to rabies virus infection, we evaluated expression of interleukin-2
(IL-2) in a standardized in vitro assay, to measure immunocompetence in
individual big brown bats. IL-2 is necessary for the development of T-cell
immunologic memory, and the expansion of antigen-specific T cell clones,
but only partial cDNA sequences are available for any bat interleukins. We
compared IL-2 gene sequences in GenBank from 16 different mammalian
species and found several regions that were 78-80% conserved, from which
degenerate forward and reverse primers for RT-PCR were designed.
Concanavalin A (ConA), a T-cell mitogen which specifically induces IL-2
production, was used to stimulate in vitro expression of IL-2 in whole blood
samples from big brown bats. Total RNA was extracted from stimulated white
blood cells, and sequence data from amplified products shared 85% identity
with reference IL-2 sequences. The proposed bat IL-2 sequences most
closely resembled those found in humans (Homo sapiens). A
semi-quantitative RT-PCR analysis detected dose-dependent induction of
IL-2 message from white blood cells in response to ConA stimulation,
whereas IL-2 expression was not detected from un-stimulated controls. This
is the first study to investigate the IL-2 gene expression response in
chiropteran hosts.
P2.193 ELNITSKY, M.A.*; BENOIT, J.B.; DENLINGER, D.L.; LEE, R.E.;
Mercyhurst College, Ohio State University, Miami University;
[email protected]
Desiccation tolerance and drought acclimation in the Antarctic
collembolan Cryptopygus antarcticus
Within the maritime Antarctic, arthropods may be challenged by drought
stress during both the austral summer, due to increased temperature, wind,
and periods of reduced precipitation, and winter, as a result of the lower
vapor pressure of the surrounding icy environment. The purpose of the
present study was to assess the desiccation tolerance of the Antarctic
springtail, Cryptopygus antarcticus, under conditions characteristic of the
Antarctic Peninsula, and examine the physiological effects of mild drought
acclimation on the subsequent desiccation tolerance. Under
ecologically-relevant desiccating conditions, springtails lost water at all
relative humidities below saturation (100% relative humidity - RH). However,
slow dehydration at high relative humidity dramatically increased the
desiccation tolerance of C. antarcticus. A mild drought acclimation at 98.2%
RH further increased the springtails desiccation tolerance. Drought
acclimation was accompanied by the accumulation of several sugars and
polyols that would function to stabilize membranes and proteins during
dehydration. The springtails were also susceptible to desiccation at subzero
temperatures in equilibrium with the vapor pressure of ice; springtails lost
~40% of their body water over 28 d when cooled to -3.0oC. The
concentration of solutes in the remaining body fluids as a result of
dehydration, together with the synthesis of several osmolytes, depressed the
melting point to approx. -2.2oC, and may therefore allow C. antarcticus to
survive much of the Antarctic winter in a cryoprotectively dehydrated state.
P3.5 EME, J*; CROSSLEY II, DA; HICKS, JW; U Cal Irvine, U N. Dakota;
[email protected]
Hemodynamics of embryonic Alligators
Embryonic reptiles and birds as well as fetal mammals have cardiac
morphologies that allow mixing of oxygenated and deoxygenated blood
(cardiac shunts). This anatomical arrangement is common in developing
vertebrates, but the significance of cardiac shunts in embryonic reptiles is
unclear. Given hypoxic nest conditions of embryonic reptiles, impacts of
cardiac mixing on physiological function must be delineated. However,
measurements of in ovo reptilian chorioallantoic membrane (CAM) and great
vessel blood flow have not been performed. Using Transonic flow probes, we
measured systemic cardiac output and major CAM artery blood flow of
normoxic and hypoxic-incubated (10% O2) American alligator embryos at
~90% of incubation. In addition, we measured normoxic CAM venous and
arterial blood gas properties. Chronic flow (2h-11d) in the major CAM artery
for hypoxic-incubated embryos (92+26ml/min/kg,N=6) was elevated
compared to normoxic-incubated embryos (29+14ml/min/kg,N=6;t-test
P=0.03). For anesthetized hypoxic-incubated embryos, acute measurements
of left aorta (LAo) flow (50+24ml/min/kg,N=5) was equal to combined flow of
right aorta, common carotid and subclavian systemic vessels
(44+21ml/min/kg,N=5). Similarly, for normoxic-incubated embryos, LAo-flow
(27+7ml/min/kg,N=5) did not differ from the other 3 vessels (18+5
ml/min/kg,N=5). CAM venous PO2 (47+6mmHg,N=5) was greater than CAM
arterial PO2 (17+3mmHg,N=5;t-test P<0.01), venous PCO2 was lower than
arterial (25+4mmHg and 37+7mmHg,respectively;P=0.03) and venous pH
was higher (7.45+0.08 and 7.32+0.07;P=0.04). A significant portion of
systemic output flows through the LAo in embryonic alligators. In addition,
alligator embryos increased CAM flow during chronic hypoxic conditions, and
this flow may be mediated by increased output to the systemic circulation, in
part via the LAo. NSF IOB 0445680 to JWH
P3.80 EMERA, D*; WAGNER, G.P.; Yale University;
[email protected]
Molecular evolution of MER-39 and consequences on the evolution of
menstruation in primates
Menstruation only occurs in species that exhibit spontaneous decidualization
of the endometrial stroma: namely, anthropoid primates and some bat
species. The adaptive significance of spontaneous decidualization is
unknown, although some have suggested that it evolved to protect the uterus
from a deeply invasive primate placenta. To understand the causes of
spontaneous decidualization in anthropoids, this study investigates the
evolution of transcriptional regulation of prolactin, a well-known marker of
decidualization. It is hypothesized here that decidual genes like prolactin
have become more responsive to luteal phase signals in the primates that
menstruate. It was previously reported that human decidual prolactin is
regulated by an alternative promoter that occurs in a primate-specific
transposable element: MER-39. To investigate the consequences of the
MER-39 insertion on prolactin expression, the taxonomic distribution of
MER-39 was first investigated by PCR and BLAST searches. Contrary to
what was previously reported, MER-39 inserted upstream of prolactin prior to
the diversification within Euarchontoglires, as we found the element in
rodents and primates. The evolution of transcription factor binding sites
(TFBS) within MER-39 was also investigated. A number of changes in
potential and experimentally verified TFBS occurred in the stem lineage of
the anthropoids, the clade in which menstruation first appears. These TFBS
include those for PR, ETS-1, C/EBP, and FOX01, proteins that are present
and active in the luteal phase of the menstrual cycle. The impact of MER-39
TFBS evolution on prolactin expression is also investigated by functional
tests comparing the kinetics of reporter gene expression driven by
anthropoid and non-anthropoid prolactin promoters.
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P1.33 ENG, AE*; CONNELLY, SJ; Rochester Institute of Technology;
[email protected]
Effects of multiple abiotic stressors on microcrustaceans, Gammarus
spp. and Artemia spp., in light of ozone depletion
Many aquatic ecosystems, including lakes, ponds, marsh, and inter-tidal
regions, are very clear waters, which expose the organisms living in these
waters to high levels of solar light, including UV radiation. These systems are
especially susceptible to climate change, as they are directly influenced by
atmospheric (UV) and terrestrial (runoff and anthropogenic inputs)
ecosystem components. UV has been shown to play a critical role in these
systems and have significant effects on aquatic organisms. Small freshwater
organisms, such as microinvertebrate crustaceans (zooplankton) that inhabit
these systems, are highly susceptible to damage from any environmental
stresses, particularly UV. This project investigates the comparative effects of
variable UVA and salinity on two related microcrustaceans from marine and
freshwater systems, Gammarus spp. and Artemia spp. Reproductive
success of both species is correlated to both UVA exposure during maternal
development and overall salinity of the environment. Understanding the
interaction of abiotic stressors on aquatic invertebrates is critical during this
time of rapid environmental changes. Species likely must develop adaptable
fitness across their populations in order to survive these highly variable
environmental factors. This will lead to new ecological and evolutionary
methodologies when considering species survival beyond their current
habitat.
P3.105 ENTZ, J. E.*; ROSTAL, D.C.; Georgia Southern University;
[email protected]
Effects of habitat quality on maternal investment in two Georgia
populations of Gopherus polyphemus.
Food for Gopherus polyphemus hinges on diversity of burn influenced
herbaceous ground cover. 2 populations with different burn regimes were
studied. Fort Stewart Army Reservation (FSAR) is frequently burned; George
L. Smith State Park (GLS) is infrequently burned. FSAR females are
significantly larger & produce significantly larger eggs & hatchling masses.
Females at GLS might be sacrificing size & the potential of larger clutches to
start reproduction earlier. Our objective was to examine the change in
maternal investment between sites & its affects on the hatchling growth &
survivorship. Female tortoises were collected from May-July (2007, 2008),
measured, X-rayed, & examined to determine clutch size. X-rays from 07-08
were measured to obtain egg size, female size, & pelvic opening. 8 nests in
07 were located at each site & temperature dataloggers were set to measure
incubation conditions. Eggs were allowed to incubate in the field for the
majority of development. During 08, 2 nests from GLS and 6 nests from
FSAR were monitored in the same manner as 07. During 08, 1 egg from
each nest was removed for component analysis. Hatchlings from 07 were
given equivalent resources & measured bi-weekly for 1 yr to obtain growth
rates. Females from both locations appear to be investing equivalent
amounts of energy into reproduction in proportion to body size.
Measurements from X-rays demonstrate females from both locations are
constrained by pelvic size & are produce eggs as large as possible for body
size. Hatchlings from both locations had similar growth rates, indicating that
observed phenotypic plasticity is due to habitat quality. So far, variables
measured indicate that habitat quality is leading to different reproductive
patterns in the 2 populations of G. polyphemus.
P1.67 ERICKSON, P.A.*; NICHOLS, K.S.; MITCHELL, G.W.; MAUCK, R.A.;
HAUSSMANN, M.F.; Kenyon College, Gambier, OH, Bowdoin College,
Brunswick, ME, Univ. of Guelph, ON, Bucknell Univ., Lewisburg, PA;
[email protected]
Don't put all your eggs in one basket: Growth, self-maintenance, and
fledgling survival in Savannah sparrow (Passerculus sandwichensis)
chicks raised in experimentally manipulated broods
Early environmental conditions can have profound and long-lasting effects on
the life history trajectory of an organism. Individuals face tradeoffs as they
allocate available energy to the competing demands of growth and
self-maintenance, and poor environmental conditions may compromise both
physiological and life history traits. We manipulated brood size in a wild
population of Savannah sparrows (Passerculus sandwichensis) nesting on
Kent Island, New Brunswick, Canada, to create reduced (2-chick) and
enlarged (6-chick) broods in order to alter food availability via intra-nest
competition. Chicks were moved between nests at age 2 days, and we
collected a blood sample and measured wing length, tarsus length and
weight at age 7 days. We recaptured fledglings 3-6 weeks post-hatch to
collect a second blood sample. Compared with reduced-brood and control
chicks, enlarged-brood chicks had shorter wings (P=0.01) and lower weights
(P=0.05) at age 7 days. Nestlings were recaptured as fledglings in a higher
proportion from reduced broods (42%) than from either control (22%) or
enlarged (11%) broods (P=0.04). Preliminary analysis suggests that catalase
activity, a measure of investment in self-maintenance, did not differ between
groups but was positively correlated to day 7 weight (P=0.04). We will also
present data on lipid peroxidation and telomere length, but our initial results
suggest that chicks allocate energy to self-maintenance rather than growth
when faced with limited resources in the wild, and this size reduction may
lower chances of survival to independence.
P3.57 ESPINOZA, N.R.*; BLOB, R.W.; Clemson Univ.;
[email protected]
Correlations of bone strain, jump performance and limb kinematics in
frogs and toads
During locomotion, the magnitude and regime of loads on limb bones can be
influenced by modifications of limb posture. In frogs, jumps of similar overall
performance (e.g., take-off velocity) show variable magnitudes of limb bone
strain. To test whether variations in limb kinematics might account for
variation in bone loading during jumping in frogs, we collected high speed
video of bullfrogs (Lithobates catesbeianus (Rana catesbeiana)) and cane
toads (Chaunus (Bufo) marinus) during jumps in which we simultaneously
recorded bone strains, and regressed strain magnitude values on several
kinematic and performance variables. Despite a large range in strain
magnitude in each species, few individuals showed correlations between
magnitudes of peak longitudinal strain and values of performance and
kinematic variables at the time of peak longitudinal strain (e.g., maximum
velocity and acceleration, and angles of femur retraction, femur adduction,
knee, ankle, tarsometatarsus, and metatarsophalangeal joints). This
suggests that unlike many other species previously examined, variation in
strain magnitude is not strongly influenced by limb position. Instead, strain
magnitudes are commonly correlated with the rate of loading. (Supported by
the NSF IOB - 0517340)
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P3.20 ESTES LAYTON , J.*; WIBBELS, T.; TUCKER, T.; WYNEKEN, J.;
EHRHART, L.; CARTHY, R.; MARTIN, E.R.; ERNEST, R.; BRESETT, M.;
JOHNSON, C.; FOURNIER, S.; SCHMID, J.; Univ.of Alabama Birmingham,
Mote Marine Laboratory, Florida Atlantic Univ., Univ.of Central Florida,
Univ.of Florida , Ecological Associates , Quantum Resources , Loggerhead
Marinelife Center , Florida DEP; [email protected]
Developing a Comprehensive Long-term Database on Nesting Beach
Temperatures of the Loggerhead Sea Turtle in the Southeastern U.S:
Applications and Implications for Global Climate Change
One of the worlds largest loggerhead populations nests in the southeastern
United States. Loggerheads have temperature-dependent sex determination
(TSD) which has implications for their ecology and conservation. The IPCC
indicates that global surface temperature has significantly increased during
the last century, and the impact on species with TSD is uncertain. The
current study is a long-term evaluation of nesting beach temperatures
throughout the range of loggerheads in the southeastern U.S. During the last
five years beach temperatures were simultaneously examined from South
Carolina to Alabama (including 23 nesting beaches in Florida) using data
loggers buried at mid-nest depth (40 cm). The results reveal the range of
beach temperatures throughout the population and provide insight on
hatchling sex ratios. Overall beach temperatures suggested female-biased
sex ratios. The temperature data were examined relative to previously
published data on the pivotal temperature and transitional range of
temperatures (TRT) for loggerheads. The results suggest many beach
temperatures are above the pivotal temperature and some are near the
upper limit of the TRT. Although loggerheads may be able to adapt
behaviorally or physiologically to increased environmental temperatures,
future increases in nesting beach temperatures could result in extreme
female biases. (This research was supported by the Florida Sea Turtle
License Plate Grant Program)
P1.158 EUBANKS, H.B.; ISAAK, S.; KIRKTON, S.D.; LEE, W.K.;
GREENLEE, K.J.*; Mississippi Valley State University, North Dakota State
University, Union College, Argonne National Laboratory;
[email protected]
Synchrotron x-ray imaging reveals tracheal system response to
hypoxia in the tobacco hornworm, Manduca sexta
Some insects are able to tolerate very low levels of oxygen by increasing
tidal volume and breathing frequency. Tobacco hornworm caterpillars also
tolerate extreme hypoxia. However, the mechanism of ventilation is unknown
in caterpillars, because they do not show abdominal pumping and lack air
sacs. Preliminary data showed that caterpillars in 3-5% oxygen exhibit
rhythmic body contractions. To test the hypothesis that these movements are
related to breathing, we used synchrotron x-ray imaging in conjuction with
high-speed respirometry to document tracheal system compression as it
correlates with body movements and gas exchange in these caterpillars. We
found that caterpillars do not show tracheal system compressions in normal
air and carbon dioxide emission is not correlated with any particular body
movement. However, in hypoxia, tracheae rhythmically compress, and the
tracheal compressions are highly correlated with external body movements
and carbon dioxide emission peaks. To further test the hypothesis that these
external movements are driving gas exchange and not just an artifact of
x-ray exposure, we performed a similar experiment in the lab using
high-speed respirometry in conjunction with videography. We again found a
high correlation between body compressions and carbon dioxide emission
peaks. These data support the hypothesis that caterpillars use ventilatory
movements to breathe in low oxygen. While caterpillars are not likely to
experience hypoxia in nature, caterpillars may experience low internal
oxygen during exercise, at high altitude or near the end of an instar when
gas exchange is more difficult.
P3.158 FAN, John; University of Maryland; [email protected]
Mathmatical analysis of Betta Splendens display behavior
Aggressive behavior amongst male animals of the same species is common.
This aggression often manifests in threatening displays, violence, or both.
The Siamese fighting fish, Betta splendens, for instance, are well known for
their aggressive behavior that is often triggered by sight alone. Inspired by
the elaborate displaying behaviors of these fish, I used probabilistic tools to
describe and analyze male male, male-female and male-mirror (self)
encounters. My initial observations allowed me to categorize twelve distinct
and consistent behaviors that occur during aggressive displays between
these fish and summarize them in an ethogram. I then recorded and
analyzed confrontations, translating the observed displays into behavioral
sequences. With this data I have been able to create first-degree Markov
chains, showing the likelihood of each fishs next behavior based on its
current behavior. Furthermore, in the case of male-male interaction, I have
used my data to show the probability of each fishs next behavior based on
both its own current behavior, as well as the current behavior of the other
fish. In determining these various probabilities, three major behavioral
patterns seemed to have emerged, which I chosen to describe as
aggressive, passive, and defensive.
P2.3 FEARS, B.C.*; MAGLIA, A.M.; Missouri University of Science and
Technology; [email protected]
Evolution of Hyoid Morphology and Call Structure in North American
Hylids
Although the ecological implications and structure of frog calls have been the
subject of much study, little is known about the association between hyoid
and cricoid cartilage morphology and call structure. In this study, we conduct
linear and geometric morphometric analyses of the hyoid and cricoid
structures of several representative North American hylid frogs and compare
them to analyses of call structure (in the context of a phylogeny of the
group). We comment on key innovations in morphology and call structure
and discuss implications for evolution and speciation in the group.
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P3.161 FENN, A.M.*; WRIGHT, A; RICHTER, M.M.; BUCK, C.L.; Colorado
State University, University of Alaska Fairbanks, University of Alaska
Anchorage; [email protected]
Behavior and Home Range of the Arctic Ground Squirrel
Behavior of free-living male arctic ground squirrels (Spermophilus parryii)
(AGS) was observed north of the Alaskan Brooks Range during the summer
months of July and early August in 2007 and 2008 to quantify aggressive,
foraging and caching behavior. In 2008, home range (HR) boundaries and
locations of afore mentioned behaviors were also observed. HR use
expanded during early and mid July, centralizing around a burrow in late July
and early August. Total HR of the males was smaller than expected. This
difference was attributed to the rigid territories males defend and the limiting
burrow space. While others have noted little to no aggression among males
during July, our behavior observations and assessment of physical condition
suggest aggression occurs consistently throughout July within areas of HR
overlap. The intensity of the interactions increased following the second
week of July around the time males began accumulating food caches. It has
been noted that hibernators will undergo a period of hyperphagia to increase
fat mass needed for hibernation. In the current study, foraging time increased
from July to August, but decreased in proportion to time above ground
correlating with increased time spent protecting a cache and engaging in
aggressive interactions. The arctic poses unique constraints to AGS. A short
active season results in a shortened breeding season as compared to more
temperate zone hibernators and thus, males must accumulate a cache in the
fall to allow them to end heterothermy and become reproductively active in
early spring. We hypothesize that the presence of a cache and limited
number of hibernacula account for the persistent territorial aggression
observed in male AGS. These constraints also appear to drive the majority of
HR and foraging behaviors.
P2.18 FIELMAN, K.T.*; UEDA, N.; Auburn Univ.; [email protected]
Skeletons Out of the Closet: Insight to Food Resource Related
Phenotypic Plasticity in the Sea Urchin, Strongylocentrotus purpuratus,
via Multiplex Gene Expression Profiling
Phenotypic plasticity in urchin larval morphology is a well-documented
developmental response to differences in food resources. When food
resources are poor, the larval skeleton enlarges to increase the surface area
for particle capture. Underlying this phenomenon is the genetic network
responsible for growth. Here, we unite larval feeding ecology and molecular
development by quantifying expression of growth-related genes from larval
urchins reared under contrasting food regimes. We developed a multiplex
qPCR assay covering 34 different urchin transcripts and used it to contrast
expression in fed and unfed plutei over time. We detected transcripts for
multiple spicule matrix protein families and proteins associated with cell
migration and rearrangement, cell signaling pathways, and fundamental
metabolic genes. Consistent with their increased skeletal growth, unfed plutei
showed strong transcriptional up-regulation of BMP5(7/8), spicule matrix
proteins MSP130(5)/SM30(A), thyroid hormone receptors, and tetraspanin.
These genes were all down-regulated in fed plutei. Unfed plutei also had
up-regulation of spicule matrix proteins SM30(D)/(F) and P16, and a carbonic
anhydrase not present in fed larvae. Furthermore, fed plutei showed
down-regulation of advillin, collagens and the spicule matrix proteins P19
and PM27, that were not present in unfed animals. Finally, unfed plutei had
up-regulated ubiquitin but down-regulated EF1a transcripts relative to their
fed counterparts. Collectively, these transcriptional-level, unique signatures
of enhanced skeletal growth in urchin plutei open a direct path to our
forthcoming, more detailed ecological and molecular-level developmental
studies.
P2.106 FILORAMO, N.I.*; SCHWENK, K.; KLEY, N.; Clark University,
University of Connecticut; [email protected]
The Presence of Numerous Cilia and Goblet Cells in the Mouths of
Snakes - a Derived Condition within Squamates
The presence of cilia and goblet cells in the esophagus of squamates
(snakes + "lizards") is well established. These esophageal mucocytes
presumably facilitate the process of swallowing and protect the esophagus
from damage during swallowing. However, the presence and distribution of
these cells in the oral cavity is poorly understood. We conducted a
phylogenetically broad comparative study of oral morphology in squamate
reptiles, and found that snakes have numerous goblet cells in their oral
cavities. Furthermore, much of the oral epithelium in snakes is ciliated with
the exception of the midline structures involved in stage I chemical delivery
to the vomeronasal organs (VNOs). These midline structures include the
sublingual plicae on the floor of the mouth, the lingual depressions in the
palate, and the vomeronasal fenestrae. The lack of ciliated epithelium on
these midline structures negates any involvement of cilia in chemical delivery
to the VNOs. The possession of abundant cilia and goblet cells in the
anterior regions of the oral cavities of snakes appears to be a unique
condition within squamates. In lizards these types of cells, which are
numerous in the esophagus, have a limited distribution in anterior portions of
the digestive tract where they appear to be limited to the pharynx/posterior
portion of the oral cavity. The presence of numerous mucocytes in the oral
cavities of snakes may be a pleiotropic effect of the anteriorization of
structures typically associated with the pharynx such as the opening of the
trachea, whose anterior position is thought to allow for breathing during the
ingestion and swallowing of whole prey items. The secretions from these
goblet cells may also aid in the intraoral transport of large prey items.
P1.141 FINKLER, M.S.*; MYGRANT, M.S.; JACKSON, A.L.; Indiana Univ.,
Kokomo; [email protected]
Dehydration Tolerance in the Rusty Crayfish (Orconectes rusticus)
Orconectes rusticus is a species of crayfish frequently found in rocky-bedded
streams and rivers. Although adapted to an aquatic environment, O. rusticus
does occasionally make terrestrial excursions, and may need to do so in
situations such as when waterways dry and where rocky beds inhibit
effective burrowing. During these terrestrial movements, O. rusticus may be
at considerable risk of dehydration. In this study, we examined the
desiccation tolerance of O. rusticus of various sizes to determine the ability
of these crayfish to cope with dehydration. Loss of righting response (LRR)
occurred when crayfish had lost 9.16 +/- 0.36% of their total body mass and
11.89 +/- 0.47% of their estimated body water contents. Hemolymph
osmolality increased linearly with mass loss during desiccation, from ca. 470
mOsm to 800 mOsm at mean LRR. Larger crayfish had overall higher rates
of evaporative water loss than did small crayfish, but had longer estimated
survival times under dehydrating conditions. Our findings suggest that O.
rusticus, like most crustaceans, is relatively intolerant of dehydration, and
rely primarily on avoidance of desiccating conditions as protection from
dehydration. Most terrestrial activity likely occurs during periods of relatively
low temperatures and high humidities, when risk of dehydration is minimized.
Moreover, it appears that only larger individuals may be capable of
prolonged overland forays.
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P2.69 FISH, F.E.*; TIMM, L.L.; MURRAY, M.M.; HOWLE, L.E.; West Chester
Univ., U.S. Naval Academy, Duke Univ.; [email protected]
Ecological morphology of the flippers of cetaceans based on
two-dimensional geometry
The pectoral flippers of cetaceans are mobile control surfaces with a
wing-like morphology that are associated with the ecology of these aquatic
mammals. The flippers contribute to lateral turning, diving, surfacing, braking,
trim control, and reduction of recoil from propulsive movements.
Biomechanically, the flippers are subjected to flows in water, which must be
controlled by the flipper geometry to reduce drag and produce lift. The
flippers of 36 species from 9 taxonomic families of cetaceans were analyzed
with regard to body length, body mass, flipper span, and flipper area. Body
mass of cetaceans was measured directly or estimated from body length.
Both flipper span and area increased isometrically with body mass with
exponents of 0.32 and 0.66, respectively. The humpback whale (Megaptera
novaeangliae) and the right whale (Eubalaena glacialis) had larger flipper
areas for their size than expected, whereas the sei whale (Balaenoptera
borealis) had smaller flippers than expected for its size. The aspect ratio,
span squared divided by area, and the flipper loading, animal weight divided
by flipper area, were calculated as indicators of shape and functionality,
respectively. To compare species, the effects of size were removed by using
principal-components analysis. In general, cetaceans with low loadings are
inshore and coastal species that specialize on fish prey, whereas high
loadings are found in cetaceans that feed on cephalopods or crustaceans.
High aspect ratio flippers are associated with pelagic species. The cetaceans
show a broad range of flipper shapes, which reflect different operational
habitats and prey types.
P3.44 FLAUTO, M. L.*; WARD, A. B.; Adelphi University; [email protected]
Impact of temperature during early development on startle responses
in adult zebrafish (Danio rerio)
Altering significant environmental conditions such as temperature during
early development can greatly affect an organisms survival. For example, it
is well-known that temperature is correlated with vertebral number in
ectothermic vertebrates. Previous work has demonstrated that fishes from
colder regions tend to have fewer vertebrae than fishes from warmer regions.
Vertebral number has also been shown to correlate with escape performance
in a number of vertebrate species, including several fish species. Most fish
perform startle responses, such as a C-start, when startled by a potential
predator. To perform a C-start, the fish bends into a C-shape followed by
rapid swimming away from the stimulus. It is likely that temperature during
development will have an impact on adult escape performance. In this study,
we raised zebrafish, (Danio rerio), at three different temperatures for six to
eight weeks. From each temperature grouping at least 10 individuals were
filmed performing C-starts. Skeletal preparations were then made for all
individuals. We have found a significant difference in performance
parameters between the temperature groupings. For example, the maximum
velocity was greater from fish raised at lower temperatures than fish raised at
higher temperatures. This study provides an important foundation for
understanding the complex interactions between environmental conditions
during development and adult survival.
P2.161 FOKIDIS, H. Bobby*; ORCHINIK, Miles; DEVICHE, Pierre; Arizona
State University; [email protected]
Increased territorial responses in urban populations of two Sonoran
Desert birds: Hormones or Ecology?
In many birds, the onset of breeding is marked by territory establishment and
its subsequent defense from conspecific intrusion. Territories may be
defended for various reasons including the monopolization of spatially limited
resources. These resources can vary between habitats, which in turn may
influence territorial behavior. We measured the territorial behavior of male
Curve-billed Thrashers, Toxostoma curvirostre, and Aberts Towhees, Pipilo
aberti, belonging to urban and rural Arizona populations through direct
observation of birds in response to conspecific song playback recordings.
Corticosterone (CORT) has been associated with avoidance behavior in
some species. In circulation, most CORT in birds is reversibly bound to
corticosterone binding globulin (CBG) and this interaction presumably
mediates the amount of free (unbound) hormone available to interact with
cellular receptors. We measured total and estimated free plasma CORT
concentrations in urban and desert thrashers and towhees and correlated
these concentrations to behavioral responses to song playback. We also
measured population densities of the two species in urban and rural areas as
it may influence aggressive interactions between conspecifics. Both urban
thrashers and towhees were significantly more aggressive than desert
conspecifics but this difference was not related to total or free plasma CORT
or to differences in population density between habitats. These results will be
discussed in the context of the effects of urbanization on behavior and
endocrine physiology.
P2.183 FORD, C. F.*; VANDENBROOKS, J. M.; HARRISON, J. F.; Arizona
State University; [email protected]
Parabolic Effects of Atmospheric Oxygen on Body Size, Development
Time, and Growth Rate in Zophobas morio, the Giant Mealworm
Changes in atmospheric oxygen over evolutionary time have been
hypothesized to be important in controlling maximal insect body size.
Previous investigations using fruit flies and mealworms have shown that
decreases in atmospheric oxygen cause linear decreases in body size.
Hyperoxia (40% oxygen) has had no effect or slightly increased size in these
species, but it is unclear whether the relationship between oxygen and size
above 21% is linear, parabolic, or flat. We measured the effect of rearing
oxygen level (10, 21, 25, 30, 40, and 60%) on the growth and development
of Zophobas morio (the giant mealworm) in both solitary and crowded
conditions. Atmospheric oxygen had a strong parabolic effect on body size,
growth rate and development time on individually reared mealworms, with
the optimal oxygen level being 30%. At 30% oxygen, these mealworms grew
the fastest, reached the largest size, and attained adulthood in the least time.
These data suggest that at oxygen levels below 30%, oxygen delivery limits
metabolism and growth, while at higher oxygen levels, oxidative stress
inhibits growth. One factor in studying the effects of oxygen on development
in mealworms is that it is know that they have higher juvenile hormone levels,
additional juvenile instars, and reach larger sizes when reared under
crowded conditions. So the question becomes - Do crowding and high
oxygen together produce superworms, or are similar maximal sizes obtained
when crowding and hyperoxia are combined? Crowded mealworms were
larger at 10, 21 and 40% oxygen, but had sizes statistically indistinguishable
from solitary mealworms at 25, 30 and 60% oxygen, suggesting that
hyperoxia and juvenile hormone are not additive effects, but may affect
mealworm development by a similar mechanism. This research has been
funded by NSF IBN 0419704 and DOD 3000654843.
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P2.10 FORMBY, K.J.*; HO, W.W.; TURNER, C. R. ; SMITH, G. T. ;
University of Wisconsin - Whitewater, Indiana University;
[email protected]
Sexually Dimorphic Communication Behaviors in Sternarchogiton
nattereri
The electrocommunication signals of electric fish differ across individuals,
species, and sexes. Each individual emits an electric organ discharge (EOD)
at a relatively stable frequency (EODf) that can serve as an indicator of sex
or species. Individuals modulate their EOD, to produce chirps and gradual
frequency rises (GFRs) that serve as social signals. Although EOD
frequency, waveform, and modulations have been studied in many species
(Turner et al. 2007; Hopkins, 1988; Kramer et al. 1981), sex differences in
these behaviors have been studied in only four apteronotid species, three of
which belong to a single genus, Apteronotus. To further examine species
diversity in the sexual dimorphism of electrocommunication signals, we
examined sex differences in EODs and chirping in Sternarchogiton nattereri.
We recorded each fish while they were presented with an array of sinusoidal
stimuli (+5Hz, 20Hz, 150hz) relative to the fishes EODf. These stimuli
encompassed the species-typical range of EODf. S. nattereri responded
robustly to playback stimuli. EODf, chirp duration, and chirp rate were
sexually monomorphic. However, S. nattereri males produced chirps with a
greater amount of frequency modulation than those of females. Combined
with previous studies on sex differences of electric communication signals in
other species, our data suggest that sex differences in chirp structure (FM
and/or duration) are relatively widespread in apteronotids, but that the
magnitude and/or direction of sex differences in EODf and chirp rate vary
considerably across species.
P2.56 FOSHA, K. R.*; DZIALOWSKI, E. M.; University of North Texas,
Denton , University of Norh Texas, Denton; [email protected]
Developmental physiology of the gut as an air breathing organ during
hypoxia-rearing in the suckermouth catfish, Hypostomus plecostomus
Hypostomus plecostomus are facultative air breathers, switching to aerial
breathing when exposed to the low oxygen conditions (hypoxia) that
commonly occur in their habitat. Digestive tract modifications, such as a thin
blood-air barrier associated with numerous capillaries running close to the
stomach lining, allow the gut of these fish to be used as an efficient
accessory respiratory organ. While much is known regarding adult H.
plecostomus, little is known about the maturation of this air-breathing organ
(ABO) in juveniles throughout early development. Initial hypoxia tolerance
tests determined that loss of righting occurred at approximately 20mmHg in
juvenile H. plecostomus without access to air. In response to acute hypoxia
(60 and 98 mmHg O2), adult fish relied almost entirely on aquatic respiration.
In contrast, juvenile H. plecostomus took between 10 and 40% more aerial
breaths per hour during hypoxic exposure than did adult fish. Due to these
observed differences in breathing rates per hour based on H. plecostomus
mass, fish have been evaluated for simultaneous oxygen uptake across the
gills, stomach and skin. Eggs were allowed to develop in hypoxia and
normoxia and aerial and aquatic respiration was measured. The information
gained from this study aids in the understanding of the development and
evolution of air breathing in fishes.
P1.12 FRANCO, L. M*; BARRIENTOS, K; SOTO-GAMBOA, M. R.; Instituto
de Ecologia y Evoluci, UACh; [email protected]
Activity patterns and huddling behavior in the rare austral marsupial
(Dromiciops gliroides)
Marsupials as other mammal species present a high diversity of
physiological and behavioral strategies to coping environmental condition in
that living. These include type of diet, diurnal pattern activity and group and
solitary living. During summer 2007 we using 108 tomahawk live-trapping for
evaluating morphometric traits and population aspects of Dromiciops
gliroides an inhabitant from the Temperate Rainforests of Austral South
America. This specie is the only living representative of the Order
Microbiotheria, and an important component of Chilean biodiversity which
contributes in the regeneration of native forest. Despite of the ecological and
evolutionary importance of D. gliroides, only recently begin to know features
of its natural history. Based in this fact, the aims of this study were (1) to
describe the daily and annual activity time of D. gliroides, and (2) to describe
the huddling patterns during torpor. We conducted this study at the San
Martin Experimental Forest at the Southern Chile. During March and April
2008 we put four automatic camera traps mounted on tree for detecting daily
activity time. We founded not significant differences in the morphometry
between sexes. However, the body mass differed significantly among
months and only tail width was significant between sexes. The sex proportion
was relatively constant and showed no differences among months. But, the
males were more abundant than the females. Our results suggest that this
nocturnal marsupial has periods of great activity during the early morning
(2:00-4:00). Finally, we show preliminary data evidencing the huddling as an
important strategy for the survival of this marsupial in the forests from Austral
South America.
P1.114 FRIESEN, Chris/R.; POWERS, Donald/R*; MASON, Robert/T;
Oregon St. Univ., George Fox Univ.; [email protected]
Cost of male courtship: Using whole group metabolic rate to assess
cost of courtship
Reproductive effort is an important aspect of life history, as reproductive
success is arguably the most important component of fitness. Females of
most sexually reproducing organisms invest more in the production of
offspring than do males. Males then tend to compete for access to females
and in the process expend their energetic capital on mate searching,
male-male competition and courtship rather than directly on offspring.
Red-sided garter snakes (Thamnophis sirtalis parietalis) are an exceptional
model for the study of energetic costs of courtship and mating as they fast
during the spring mating season segregating the cost of energy acquisition
from the cost of courtship and mating. However, in this species measuring an
individual males metabolic rate during courtship is complicated by the fact
that male courtship behavior in red-sided garter snakes is dependent on the
detection of female sexual attractiveness pheromones, and facilitated
courtship, i.e., vigorous courtship is only exhibited in the presence of other
males. Thus, traditional techniques of masking individuals prevents male
courtship behavior, and single animals placed in a flow-through chamber
would not yield ecologically realistic levels of courtship, which are only seen
in the context of a group or mating ball. Because of these difficulties, we
placed groups of males in a flow-through metabolic chamber together with a
single female whose respiratory gases were vented outside the chamber to
yield a whole group metabolic rate during competitive courtship.
Conservative estimates of peak group metabolic rates during courtship are
10-20 times higher than resting group metabolic rates. These measurements
indicate that costs of male courtship are high for males and may have
implications for the evolution of alternative male mating strategies in this
system.
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P3.31 FRUTIGER, A.E.*; HOLDENER, J.A.; ITAGAKI, H.; Kenyon College;
[email protected]
The calculation of the body surface areas of Manduca sexta larvae
using serial sections followed by image reconstruction and the creation
of parametric body surface models.
We have attempted to calculate the body surface areas (BSA) of 2nd, 3rd
and 4th instar larvae of the sphinx moth, Manduca sexta, of various body
weights (BW). The larvae were reared from eggs on a prepared diet, then
frozen and embedded in Histoprep along with four external orientation
markers to serve as reference points between sections. A cryostat was used
to make transverse serial sections of each larva at 50um. Each section was
digitized using a stereomicroscope equipped with a digital camera and
polarization optics. The images of the sections were then imported into the
NIH Image J program for analysis. The distances between each of the 4
orientation markers was measured and used to estimate the centroid of each
section. A line drawn between the centroid and the upper left marker dot
served as the reference axis between sections. For each section, 36 radius
measurements were taken from the centroid to the surface in 10 o
increments. Each set of radii values was imported into MAPLE, in which a
parametric model of the boundary curve was constructed from 10 sections in
the 2nd instar, 30 sections in the 3rd instar, and 28 sections in the 4th instar.
A second program in MAPLE was then used to create a parametric model of
the body surface for each instar in addition to finding the surface area; the
centroid for each section was used to determine a space curve that served
as the generating curve for the body surface. These calculated surface areas
were then divided by the body weights to find the BSA/BW values for each
instar: 2nd instar, 18.8 cm 2 /g (BW = 0.039g); 3rd instar, 8.5 cm 2 /g
(BW=0.309g); 4th instar, 7.6 cm 2/g (BW=0.787g). This work was supported
by the Kenyon College Summer Science Scholars Program.
P3.184 FUJIMURA, Koji*; OKADA, Norihiro; Tokyo Inst. of Tech, Yokohama,
JAPAN; [email protected]
The developmental basis for craniofacial morphology of cichlid fishes
Cichlid fishes of Great African Lakes are excellent examples of explosive
adaptive radiation. One of the most important traits by which we can
distinguish each species is the shape of feeding apparatus, which has been
adapted to the wide variety of trophic habitats present in the lake. To study
the molecular mechanism underlying the diversification of cichlids jaw shape,
we need to understand the developmental basis of craniofacial morphology
in the cichlids. First, we described the developmental stages for the
embryonic, larval and early juvenile periods of Nile tilapia Oreochromis
niloticus. We newly defined 32 stages using a numbered staging system. For
embryonic development, we defined 18 stages (St.1-18), which were
grouped into seven periods. For larval development, we defined seven
stages (St.19-25), which were grouped into two periods. For juvenile
development until 30 dpf, we defined seven stages (St.26-32) in the early
juvenile period. Second, we described the identification, the timing and the
sequence of the skeletal elements of Nile tilapia, categorized by the
developmental stages. The chondrogenesis started in St.17. The deposition
of osteoid for the dermal bones started in Stage 18. The uptake of calcium
dramatically shifted from the surface of the larvae to the gills in St.20. The
bone mineralization of the skeleton started in St.25. Third, we assessed the
shape changes of the lower jaw bone during development of Nile tilapia and
a Lake Victoria cichlid Haplochromis chilotes using geometric
morphometrics. Principal component analysis showed both commonalities
and differences in the morphological changes between the cichlids. These
data provide basic information as a starting point for understanding the
molecular mechanisms underlying this adaptive trait of East African cichlids.
P3.73 GAINEY, L.F., JR*; GREENERG, M.J.; Univ. of Southern Maine,
Portland, C.V. Whitney Lab., Univ. of Florida, St. Augustine;
[email protected]
Nitric oxide is the agent of seasonal temperature compensation of
clearance rates in isolated gills of Mercenaria mercenaria
The gills of the clam Mercenaria mercenaria contain a seasonally expressed
nitric oxide (NO) signaling cascade. In gills isolated in winter, NO potentiates
the effects of 5HT on both muscle contraction and the rate of particle
clearance, but NO has no effect during the summer. We wondered whether
NO acts by mitigating the effects of lower temperatures on clearance rates
during the winter. To test this hypothesis, we acclimated clams to 5, 10 and
22 C during the summer and the winter. One set of isolated gills was
exposed to 10-5 M 5HT to maximize the rate of clearance, and the other set
to both 5HT and 10-5 M L-NAME, the latter to inhibit the synthesis of NO. A
three-way full factorial ANOVA, with season, temperature and treatment
(5HT or 5HT and L-NAME) as the main effects, revealed that only season
and season*treatment were significant. Post hoc analysis of the
season*treatment means revealed that: 1) temperature had no effect on
clearance rates in either season; and 2) L-NAME had no effect during the
summer, when the NO signaling cascade is not functional; but 3) during the
winter and at all temperatures, L-NAME significantly reduced clearance
rates. These results support our hypothesis that NO is the agent of seasonal
temperature compensation of clearance rates.
P1.115 GALINDO, Joanna*; GALINDO, Gracie; IRWIN, Jason T.; Central
Washington Univ.; [email protected]
The Effects of Temperature on Metabolic Rate, Venom Synthesis and
Potency in Peucetia viridans (Araneae: Oxyopidae)
We examined the effects of temperature on metabolic rate, venom synthesis
and potency in the green lynx spider, Peucetia viridans, from Yavapai
County, AZ. After acclimation for 7-12d at 10, 20, or 30°C, metabolic rates
were measured using flow-though respirometry (n=14/group). Venom was
extracted every 6d using electrical stimulation (n=20, 19, 16, for 10, 20, and
30°C, respectively). Potency was tested by injecting 0.5l of crude venom into
crickets (Acheta domesticus), and recording the time from initial injection to
loss of the righting response and to death (no visible heartbeat). Metabolic
rates increased with temperature (10°C: 0.036+/-0.004; 20°C:
0.107+/-0.018; 30°C: 0.288+/-0.061 lCO2mg-1h-1). After 6d, the volume of
venom extracted was considerably higher at 20°C (3.41mg/spider), than 10
(0.478mg/spider) or 30°C (1.002mg/spider). By day 18 venom production
was low in all groups. Spiders at 10°C produced very little or no venom
throughout the experiment. Crickets injected with venom from spiders at
20°C (n=21) had a faster collapse time and were less likely to recover than
those injected with from the 30°C spiders (n=21). Chemical analysis will be
conducted in the fall 2008 to identify differences in protein content and
composition.
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P3.149 GAM, A.E.*; MENDON, M.T.; NAVARA, K.J.; The University of
Georgia, Auburn University, Then University of Georgia; [email protected]
Effects of progesterone and corticosterone administration on offspring
primary sex ratio in the zebra finch (Taeniopygia guttata)
Researchers have documented significant skews in the primary sex ratios of
avian offspring in relation to a variety of environmental and social cues.
Zebra finches, in particular, adjust offspring sex ratio according to both the
quality and quantity of available food, as well as the attractiveness of the
male. The mechanisms behind such manipulation of offspring sex, however,
remain elusive. Recent studies suggest that progesterone may exert
influences on the sex of offspring in birds: Progesterone administered to
leghorn hens during the segregation of sex chromosomes stimulated the
production of significantly more females, and corticosterone implants
resulted in a significantly higher ratio of female offspring in Japanese quail.
We tested the effects of a administering a pharmacological dose of
progesterone or corticosterone to females at the time of sex chromosome
segregation on the primary sex ratio of zebra finch offspring. Females were
injected intraperitoneally with 20ug of either progesterone or corticosterone
dissolved in 100ul of peanut oil, or with a control oil vehicle six hours prior to
the predicted time of ovulation. Follicles ovulated immediately after injection
were laid two days later, and were marked and returned to the nest.
Following three days of incubation and embryonic development, eggs were
collected and embryos sexed through PCR amplification of a portion of the W
chromosome, after which sexes of eggs injected with progesterone or
corticosterone were compared with control eggs. Results and implications
will be discussed.
P2.22 GAO, S.*; BENFORD, R.; SHUSTER, S.M.; BALDA, R.P.; The
College of New Jersey, Ewing, Northern Arizona University, Flagstaff;
[email protected]
Temporal Changes in Population Dynamics of the Pinyon Jay
Drought-induced pinyon pine die-off in Flagstaff, Arizona during 2002-03 had
cascading effects in the pinyon jay. Effects include changes in flock
demographics and organization. Two hypotheses have been generated to
explain the changes. The first hypothesis suggests that changes in
reproductive behavior have affected relative fitness among flocks. The
second hypothesis suggests that changes in dispersal patterns have caused
a source/sink dynamic to form among flocks. Observational analysis of
relative fitness, and observational and genotypic analysis of dispersal
behavior have found support for both hypotheses. Varied relative fitness and
rates of dispersal among flocks before and after the drought have changed
age and population structure, and have caused flocks to become sources
and sinks. Changing patterns of fitness and dispersal suggest adaptive
changes in behavior.
P3.193 GARCIA, NW*; GREIVES, TJ; DEMAS, GE; Indiana University;
[email protected]
Insulin affects immune responses differentially in reproductive and
non-reproductive Siberian Hamsters (Phodopus sungorus)
Many animals living in temperate clines experience relatively predictable
seasonal changes in environmental conditions and utilize photoperiodic cues
to predict these environmental changes. Most non-tropical mammals must
re-allocate finite energy reserves from systems not critical to immediate
survival (e.g., immunity) to systems critical to immediate survival (e.g.,
thermoregulation) and rely environmental cues (i.e., photoperiod) to trigger
these adaptations. The seasonal attenuation of immune function is likely
regulated by endocrine signals indicating the amount of energy available to
the animal. For example, recent research has demonstrated changes in
immune functioning in response to the adipose hormone leptin. In addition,
the pancreatic hormone insulin is also released in response to elevated
blood glucose levels and may indicate readily available energy to the central
nervous system. The aim of the present study was to determine the role of
insulin in signaling energy status and investment in immune function in
animals held under varying photoperiod conditions. To this end, exogenous
insulin was administered to reproductive long-day (16:8 L:D) and
non-reproductive short-day (8:16 L:D) housed Siberian hamsters (Phodopus
sungorus). Hamsters were then challenged with an innocuous antigen,
keyhole limpet hemocyanin, and immune response was measured. Insulin
treatment significantly enhanced immune response in short-day but not
long-day hamsters. These data suggest a role for insulin as a
neuroendocrine signal integrating seasonal energetic changes and immune
responses.
P1.95 GASSER, B.A.; PANESSITI, M.*; YAGER, D.D.; Univ. of Maryland,
College Park; [email protected]
Sudden shadow triggers a short-latency behavioral response in flying
praying mantises
An abrupt decrease in light intensity from a small overhead source elicits a
complex behavior in flying praying mantises both in tethered flight and in
free-flight. In Pseudocreobotra ocellata, the response comprises a complete
extension of the prothoracic legs, changes in wing beat pattern, dorsal
abdominal muscle contraction, and sometimes a head roll. In addition, the
mesothoracic and metathoracic legs move slightly away from their normal
tucked position. An abrupt increase in light intensity (flash or sustained) did
not trigger any behavior. The latency to the beginning of the prothoracic leg
movement is 40-60 ms and the wing beat changes start within two cycles
(60-80 ms). Wing beat rate, phase, and amplitude changes were obvious in
laser/photocell and EMG records, but were markedly inconsistent in
magnitude. Shadow never caused flight cessation, and it triggered flight in
non-flying animals hanging without tarsal contact. Lowering the contrast
between full light and shadow reduced the response magnitude. Three
additional mantis species also responded strongly to sudden shadow.
Although closely resembling the ultrasound-triggered evasive response,
there are differences between the behaviors, most obviously in the
prothoracic leg extension. High-speed video shows that for ultrasound, the
sequence of extension of the three leg joints is proximal to distal, but it is
distal to proximal for shadow stimuli. Also, the response to ultrasound greatly
outlasts the stimulus, but stimulus and response durations are the same for
shadows. P. ocellata and Hierodula grandis flying untethered in a large room
responded to lights-off with an abrupt dive followed by acceleration upward.
Direction change ranged from 0 to 180 to either side. Suddenly increased
light intensity had no effect. We suggest that sudden shadow and ultrasonic
stimuli during flight may tap into the same CNS module for defensive
behavior.
e233
P3.89 GATICA SOSA, C.; CHEDIACK, J.G.; JURI AYUB, M.; KARASOV,
W.H.*; CAVIEDES-VIDAL, E.; Univ. Nac. San Luis, IMIBIO-SL, San Luis,
Argentina, Inst. Leloir, Argentina, Univ. of Wisconsin, Madison;
[email protected]
Expression of the intestinal brush border disaccharidases and
Na+/glucose cotransporter genes of zebra finch (Taeniopygia guttata)
Digestive function of passerine birds (i.e. rates and capacities of intestinal
nutrient hydrolysis and absorption) and its ecological implications has been
studied extensively in different species at different levels of integration.
However, to our knowledge the level of expression of the different intestinal
membrane-bound enzyme and nutrient transporter genes that participate in
the digestion and its regulation has yet not been assessed in passerines.
Thus, our objectives were: (1) to assess mRNA levels along the small
intestine for the intestinal enzymes sucrase-isomaltase (SI) and
maltase-glucoamylase (MG)] and the Na+/glucose cotransporter (SGLT1),
and (2) to associate the mRNA levels of the enzymes to their specific
activities. Our passerine bird models were adult zebra finches, because they
are easy to obtain and maintain, and their genome is being sequenced. We
designed several primers using predicted sequences of SI, MG and SGLT1
genes for chicken and selected those that produced fragments with the
highest percentage of homology to the zebra finch genome. cDNA fragments
obtained by RT-PCR were cloned and sequenced for validation. We
determined the abundances of mRNAs and activities along the small
intestine for SI and MG, whereas for SGLT1 only mRNA abundance was
assessed. SI mRNA abundance and activity were correlated and exhibited
significant positional differences along the small intestine possibly indicating
a transcriptional regulation. Interestingly, neither MG nor SGLT1 revealed a
significant correlation or differences in the activity or mRNA abundance along
the intestine. Supported by FONCYT PICT 25561, UNSL-CyT 22Q751 to
EC-V, and NSF IOS-0615678 to WHK.
P1.27 GAULKE, Christopher A.*; IRWIN, Jason T.; Central Washington
Univ.; [email protected]
High infection rates of the fungus Batrachochytrium dendrobatidis in
biological supply and wild-caught frogs in central Washington State,
USA.
The fungus Batrachochytrium dendrobatidis (Bd) has been linked to mass
mortality events and population declines in amphibians worldwide. To
describe the distribution and prevalence of Bd in central Washington State
we sampled three montane ponds between June and September 2008
(1430-1550m). Each anuran was swabbed with a sterile cotton tipped swab
to dislodge epithelial cells. The cells were then visualized using differential
interference contrast microscopy for the presence of zoosporangia.
Batrachochytrium dendrobatidis was found at all sample locations with a total
prevalence of 49%. Species-specific infection rates were not significantly
different: 52% in the Columbia Spotted Frog (Rana luteiventris) (n=15), 53%
in the Cascade Frog (Rana cascadae) (n=67), and 40% in the Pacific
Treefrog (Pseudacris regilla) (n=10). There were also no significant
differences in infection rates between sites and all frogs appeared healthy. In
addition, Northern Leopard Frogs (Rana pipiens) shipped to Central
Washington University in October 2006 and July 2007 were screened for Bd.
All frogs tested positive for Bd (n=38). These data confirm the presence of
Bd in central Washington and in the amphibian trade. We urge the use of
proper sterilization techniques when handling and disposing of amphibian
wastes to reduce the risk of accidental spread of the pathogen.
P1.16 GERKEN, S.; University of Alaska, Anchorage;
[email protected]
Playing in the mud: Cumacea (Crustacea) of the Comau Fjord, Chile
Cumaceans are small, benthic marine crustaceans that are commonly
encountered in mud and soft sand substrates, at depths from the intertidal to
deep-sea trenches. As peracarid crustaceans, cumaceans brood their young
in a pouch on the ventral surface of the body, with the young directly
developing into small copies of the adults. Distributions tend to be patchy
and seasonal, although cumaceans can be extremely abundant. Cumaceans
are frequently recorded as part of the diets of bottom feeding fish and shore
birds. However, very little is known about these organisms, including total
diversity, biogeography, ecology, etc. Recent benthic sled collections in the
Comau Fjord and connected smaller fjords yielded 11 cumacean species in 7
genera, from 3 families. At each sample site, from 1-9 species were
collected. Many of the populations were reproductive, with adult males and
eggs in the brood pouches of the females. No specimens were collected via
light trapping (usually a successful collection method), despite several
attempts and prominent eye lobes present in some of the species.
P1.52 GERRY, S.P*; SCOTT, A.J.; Arcadia University, University of Rhode
Island; [email protected]
Prey selection by two species of sharks
The degree of plasticity or degree of specialization of an organism can often
determine its distribution within a community. More specifically, the
morphology or behavior of a predator can influence resource acquisition.
Foraging in the presence or absence of a competitor was investigated by
quantifying prey selection in a trophic generalist, spiny dogfish, and a trophic
specialist, smooth-hounds, when offered five types of prey. The diet of spiny
dogfish consists of small fishes, squid, ctenophores and bivalves. Therefore,
dogfish are expected to be nonselective predators and will show no
preference for any one prey item. Smooth-hounds have morphological
specializations for crushing and primarily feed on crustaceans, thus, they are
predicted to select crabs over non-crustacean prey types. Prey selection was
quantified according to a selection index that ranks each prey item by the
order in which it was consumed. The percentage of consumed prey, missed
strikes at a prey and ignored prey were calculated as a proxy for predator
efficiency. In the absence of competition, both species showed a preference
for herring, squid and shrimp and no preference for crabs. Smooth-hounds
frequently selected crabs, but chose not to consume them. Smooth-hounds
did not show a feeding specialization according to published diet studies, yet
by showing a preference for some prey types, they can be characterized as a
selective predator. In the presence of a competitor, spiny dogfish selected
four of the five prey items equally, as predicted for a generalist nonselective
predator. Similarly, smooth-hounds showed no preference for any one prey
type. It is possible that the presence of a competitor influenced both species
to select any available prey in order to gain maximum fitness.
e234
P1.116 GERSON, A.R.*; GUGLIELMO, C.G.; University of Western Ontario,
Canada; [email protected]
Evidence for increased protein catabolism as a result of
water-restriction in House sparrows.
During migration, non-stop flights are fuelled exclusively by endogenous
energy stores and pose a significant physiological challenge, especially
when considering fuel and water management. Long distance migrants
mobilize a fuel mixture consisting of up to 90% lipid and 10% protein.
Although many theories have been proposed, the role of protein catabolism
in endurance exercise remains unclear. The catabolism of lipids yields little
metabolic water (0.029 g H2O kJ-1) relative to protein catabolism (0.155 g
H2O kJ-1). Thus, it has been proposed that protein may be metabolized as a
source of water during long distance flights under dehydrating conditions.
Protein is catabolized directly from muscles and organs, which may have
consequences to flight performance and stopover refueling efficiency. Thus,
the goal of this study was to investigate the possible affect of water
restriction on fuel use during rest and simulated endurance exercise
(shivering) in house sparrows (Passer domesticus ). Magnetic resonance
body composition analysis was used to measure changes in body
composition (fat and lean mass) through an 18 hr water restriction followed
by a 4 hr shivering trial. Blood samples were taken before and after the
shivering trial for the determination of plasma osmolality and plasma
metabolite analysis. Flow through respirometry was used to measure
metabolic rate and total evaporative water loss before and during shivering.
Water restriction resulted in significantly greater lean mass loss relative to
control birds, elevated plasma uric acid levels, and higher plasma osmolality.
These data provide preliminary evidence supporting the hypothesis that
negative water balance may result in increased protein catabolism, possibly
as a strategy to offset high rates of evaporative water loss.
P1.48 GERSTNER, GE; University of Michigan; [email protected]
Chewing Rate Allometry Requires Natural Selection
Mammalian chewing is produced by brainstem circuits called central pattern
generators, which can be functionally subdivided into burst-generating
neurons and a central timing network (CTN). The CTN generates a rhythm
that sets chewing rate. Chewing rate scales allometrically to body mass, and
it is generally assumed that feedback and feedforward systems adjust
chewing rate to match the jaws natural resonance frequency. However,
studies have shown that oral motor rhythms are unaffected by experimentally
increasing jaw mass. But these studies were not specifically designed to
explore chewing rate scaling, and none involved determining whether
chewing rate required developmental time scales to adapt to experimentally
increased jaw mass. Therefore, we studied chewing rate and body mass
relationships among 20 dog breeds, ranging in size from 3.6 kg (beagle) to
68 kg (Newfoundland) and 20 matched wild mammalian species. Chew
duration was not significantly correlated with body mass among dog breeds
(p = 0.418, r2 = 0.023). By contrast, a significant correlation between body
mass and chew duration was found among the 20 mammalian species (p =
0.002, r2 = 0.284). Next, canine jaw masses were estimated by taking the
product of body mass and the ratio of head length to body length. Estimated
jaw mass was also not significantly correlated with chew duration among the
dog breeds (p = 0.627, r2 = 0.008). The results suggest that chewing rate
allometry requires natural selection; neural feedback and feedforward
mechanisms alone do not necessarily guarantee the allometric relationship.
The results demonstrate that, at least among domestic dog breeds, relaxed
selection pressure can greatly reduce the allometric scaling relationship,
which may have significant implications for neuromotor, biomechanical,
functional morphological, ethological and ecological investigations.
P3.90 GIAMBRONE, T.P.; LIGNOT, J.-H.; SECOR, S.M.; FREDERICK, J.*;
University of Alabama, CNRS, DEPE, Strasbourg;
[email protected]
Maintenance of digestive performance is ontogenetically stable for the
American alligator
We investigated whether the American alligator (Alligator mississippiensis)
experiences ontogenetic shifts in the magnitude of their postprandial
metabolism and in the regulation of gastrointestinal morphology and function
with fasting and feeding. Neonate (38-62 g), juvenile (740-989 g), and
subadult (2340-5240 g) alligators all experienced a rapid postprandial
increase in metabolic rate following rodent meals weighing 5% of body mass
that peaked at 2.73, 2.92, and 3.64-fold of standard metabolic rate,
respectively, at 36 or 48 hours postfeeding. Specific dynamic action,
independent of body mass, was significantly higher for subadult alligators.
We observed no significant postprandial change in the mass of the small
intestine or any other organ for neonate, juvenile, and subadult alligators.
Alligators also did not exhibit any postprandial change in intestinal microvillus
length. Gastric pH and the pH of other sites of the GI tract did not differ
between fasted and fed alligators. For each age class, feeding did not
generate any significant change in pancreatic trypsin activity or total
pancreatic typsin capacity. For the three age classes, small intestinal nutrient
uptake rates seldom differed between fasted and fed alligators, and there
was no postprandial change for each age in intestinal nutrient uptake
capacity. Independent of alligator body mass, intestinal mass and uptake
rates and capacities decreased with age. Similar to species of frequently
feeding reptiles, alligators maintain gastrointestinal form and function
between bouts of fasting and feeding.
P1.57 GIBB, A; MELVILLE, B*; WALSH, K; FERRY-GRAHAM, L; Northern
Arizona University, Moss Landing Marine Laboratory; [email protected]
Why don't kissing gourami capture prey from the water column?
The kissing gourami Helostoma temminkii, are members of the monotypic
family Helostomatidae (Anabantoidei), characterized by their unusual jaw
morphology and associated "kissing" behavior. However, the jaws in this
species appear to be additionally modified to enable scraping algae from the
substrate. We quantified the cranial movements produced during feeding in
Helostoma and in two gouramis from the closely related family
Osphronemidae: Betta splendens and Trichogaster trichopterus. We
observed that Helostoma will take attached food by scraping it from the
substrate or detached food by capturing it between the upper and lower jaws
from the water's surface or from the tank bottom; they will rarely take it from
the water column. Helostoma appear to produce very little suction while
feeding; food was only drawn into the buccal cavity after being encompassed
by the anterior jaws, and was never drawn into the buccal cavity from a point
anterior to the mouth-gape. Correspondingly, Helostoma produced very little
cranial rotation (~6 deg.) and hyoid depression (~4%) during scraping ;
although they produced somewhat more when removing unattached food
from the bottom of the tank (~10 deg. and ~12%, respectively). Trichogaster
produced similar rotation and hyoid depression to Helostoma when feeding
on dettached prey resting on the bottom. However, Betta produced
substantially more cranial rotation (~16 deg.) and expansion (~22%) when
suction-feeding in the water column. We suggest that the highly-modified jaw
morphology of Helostoma is associated with a reduction in suction feeding
performance, potentially to the extent that they are unable to produce the
buccal expansion necessary to capture prey from the water column.
e235
P2.68 GINTER, C.C.*; FISH, F.E.; MARSHALL, C.D.; West Chester Univ.,
Texas A&M Univ. Galvestron; [email protected]
Morphology of the bumpy profile of phocid vibrissae
The geometry of projecting sensory structures may use a passive
mechanism of flow control. The vibrissae of phocid seals have an ellipsoidal
cross-section with a regularly repeating sequence of crests and troughs to
give a wavy or bumpy profile along the length. This morphology suggests
hydrodynamic properties when swimming. The morphology of phocid seal
vibrissae was investigated for harp (Phoca groenlandica), grey (Halichoerus
grypus), and hooded (Cystophora cristata) seals. The overall length of each
vibrissa, the number of crests, wavelength, width of crests and width of
troughs were measured. Mean number of crests per vibrissa ranged from 9
for the grey seal to 12 for the harp seal. For all species, the middle of the
vibrissae showed the greatest wavelength, crest width and trough width,
while the tip showed the lowest wavelength, crest width and trough width.
The grey seal vibrissae showed the greatest wavelength, crest width and
trough width at 3.91 mm, 0.97 mm and 0.79 mm, respectively. The hooded
seal vibrissae showed the lowest wavelength and crest width at 1.77 mm and
0.26 mm, respectively, and the harp seal vibrissae showed the lowest trough
width at 0.19 mm. The number of crests increased toward an asymptote with
increasing vibrissae length for all species. The crest to trough ratio was 1.38,
1.33 and 1.23 for the harp, hooded and grey seals, respectively. The bumpy
profile of the vibrissae may modify the flow of water to reduce vibrations as
the seal swims. Decreased vibration on the vibrissae could increase the
signal to noise ratio of the tactile vibrissae and aid in the detection of
turbulent flow fields generated by prey organisms.
P3.166 GLASSMAN, L W*; BUTLER, L K; ROMERO, L M; Tufts University;
[email protected]
Behavioral responses of an endangered and a common bird to
disturbances at the nest
Disruption of breeding activities due to human disturbance is commonly
blamed for the decline of many animals around the world. However, indirect
effects of human activity in breeding habitat are rarely separated from direct
effects of humans degrading and destroying breeding habitat. We studied the
behavioral responses of an endangered songbird, the Black-capped Vireo
(Vireo atricapilla), to a human sitting or standing 1-2 meters from active
nests. We compared responses of Black-capped Vireos to responses of their
common and widespread congener, the White-eyed Vireo (V. griseus). Both
species build cup-shaped nests hanging from the tips of branches of trees
and bushes 1-2 m above ground. Because this exposed nest style permits
adults to easily detect and escape from nest-directed threats, we predicted
that adults would rapidly habituate to a human at the nest, as evidenced by
increased willingness to approach the nest, increased willingness to incubate
eggs or brood nestlings, and decreased alarm behaviors during 30-minute
disturbances repeated over several days. We also compared willingness to
incubate or brood during human disturbance to willingness to do so during a
simulated predator threat or a novel object placed near the nest. If mild forms
of human activity during the breeding season are a cause of population
decline in Black-capped Vireos, then Black-capped Vireos should habituate
to disturbances more slowly than White-eyed Vireos. Our study illustrates
how sensitivity to mild forms of human activity may contribute to the decline
of a migratory songbird.
P3.135 GONYER, Kristy M.*; MCCOY, Michael W.; VONESH, James R.;
WARKENTIN, Karen M.; Reed College, Boston University, Virginia
Commonwealth University; [email protected]
Effects of Habitat Structure on Predation of Agalychnis callidryas
tadpoles by Giant Water Bugs (Belostomatidae)
Predation success is often affected by abiotic factors such as a habitats
structural complexity. Habitat structure can inhibit predator efficiency by
hindering search efforts, impeding pursuit of prey, or providing refugia for
prey. Conversely, habitat structure can increase predation success when
prey are associated with particular structural features or when elements of
the habitats structure enhance a predators searching behavior. In this study,
I characterize giant water bug (Belostomatidae) foraging behavior and
success in different structural environments. Observations revealed that the
insects alternate between active searching and use of habitat structure in a
sit-and-wait strategy when foraging for red-eyed tree frog (Agalychnis
callidryas) tadpoles. To test whether structure affects the behavior and
foraging success of belostomatids I constructed mesocosms with artificial
structure placed in bottom, mid, or upper water-column, all water-column
levels, and without structure. The belostomatids behavior was observed to
quantify use of structure and predation success was measured by running 24
hour predation trials. I found that belostomatids tended to use structure when
available and they tended to use structure in the lower water column when
given a choice. The belostomatids had higher predation success when in
tanks with rather than without structure, and predation success was highest
when there was structure lower in the water column. In addition, when given
a choice, belostomatids tended to use structure in the lower water column
where they tended to have the highest foraging success.
P2.19 GONZALES, Vanessa A.*; TSUKIMURA, Brian; California State
University, Fresno; [email protected]
Eriocheir sinensis megalopae abundance in regions of the San
Francisco Bay Estuary
Little is known about the population dynamics of the megalopa stage of the
Chinese mitten crab, Eriocheir sinensis, in the San Francisco Bay estuary.
The aim of this study was to determine megalopa abundance in regions of
the San Francisco Bay estuary. Megalopae abundance may be determined
by the use of light traps. Larval light trap samples were obtained from the
Smithsonian Environmental Research Center. The light trap samples were
deployed biweekly in areas of the San Francisco Bay/Delta system including
Point San Pablo, McNears Beach, and Point Pinole Regional Shoreline
during March 2007 - June of 2007. Light trap samples were deployed
biweekly during March - July of 2008 from sample sites including Point San
Pablo, Point Pinole Regional Shoreline and Point Molate. Previously, a
dichotomous key was made for the brachyuran megalopae of the San
Francisco Bay, thus allowing us to identify and quantify E. sinensis
megalopae in light traps samples taken from the bay in 2007 and 2008. Site
Point San Pablo was the only sampling site where E. sinensis megalopae
were found. E. sinensis megalopae were found in light trap samples taken
during April 2007 - May of 2007 and May of 2008. Almost all megalopae
were found in the month of May. For 2007, all E. sinensis megalopae were
found in samples taken on the day after the new moon. For 2008, E. sinensis
megalopae were found in samples taken on the day of the full moon. It is
possible that E. sinensis megalopae use lunar cycles to disperse to areas
that are more suitably for settlement and metamorphosis. However, given the
minimal amount of data collected in this study, further research would have
to be done to support this hypothesis.
e236
P3.177 GORB, E.V.*; HOSODA, N.; GORB, S.N.; MPI for Metals Research,
Stuttgart, Germany, NIMS, Tsukuba, Japan, Univ. of Kiel, Germany;
[email protected]
Absorption Hypothesis: Attachment of Beetles to Nano-Porous
Substrates
It has been repeatedly reported that microstructured waxy surfaces of plants
strongly reduce insect attachment. To explain anti-adhesive properties of
such plant substrates, four hypotheses were previously proposed. Recently,
only the two first hypotheses (roughness hypothesis contamination
hypothesis) and were proven. The aim of this study was to test the third, fluid
absorption hypothesis, claiming that the structured wax coverage may
absorb the fluid from the setal surface of insect adhesive pads and by this
reduce the adhesion force. Traction force measurements were performed
with tethered seven-spotted ladybird beetles Coccinella septempunctata L.
(Coleoptera, Coccinellidae), walking on five different substrates: (1) smooth
glass plate; (2) smooth solid Al2O3 (sapphire) disc; (3 - 5) porous Al2O3 discs
(anodisc membranes, back side) with the same pore diameter (220 - 235
nm), but different porosity (28, 42 and 51%). The force ranged from 0.16 to
16.59 mN in males and from 0.32 to 8.99 mN in females. The highest force
values were obtained on the smooth surfaces, where males generated
considerably higher forces compared to females. On all three porous
substrates, forces were significantly reduced, and the only difference for
surfaces was obtained between anodisc membranes with the highest and
lowest porosity. Males produced essentially lower forces than females on
porous samples. The reduction of insect attachment on anodisc membranes
may be explained by (1) possible absorption of the secretory fluid from insect
pads by porous media and (2) surface roughness, reducing real contact area
between tenent setae and substrate.
P3.107 GOVINDARAJAN, A.F.*; BUCKLIN, A.; MADIN, L.P.; Woods Hole
Oceanographic Institution, MA, University of Connecticut, Avery Point;
[email protected]
The Evolution of the Thaliacea and Its Significance for Tunicate
Phylogeny
Thaliaceans are pelagic tunicates that have a close relationship with the
benthic and relatively more studied ascidians. The Thaliacea is composed of
3 holoplanktonic groups exhibiting varying degrees of coloniality and life
cycle complexity: the Pyrosomatida, Salpida, and Doliolida. Previous studies
based on 18S rDNA sequences have shown that the Thaliacea falls within
the Ascidiacea. However, the exact relationships within the Thaliacea and
between thaliacean and ascidian lineages remain to be detailed. A major
limitation to date in reconstructing thaliacean phylogeny has been the
availability of samples for sequencing. Thaliaceans are relatively difficult to
obtain and preserve, and there are few experts capable of accurate species
identification. Here, we present a phylogeny of the Tunicata that includes
new 18S rDNA sequences for all 3 thaliacean lineages. We also examine the
relationships within the thaliacean lineages and discuss implications for life
cycle evolution.
P3.95 GRAHAM, Sean P*; SEWELL, Leanne M; Auburn University;
[email protected]
The effect of temperature and reproductive condition on snake
complement activity
Most vertebrate physiological systems (e.g., the endocrine system) are
highly conserved; however, the extent to which the immune system exhibits
this conservatism is not as well known. Vertebrate complementan innate
immune response involved in the incapacitation of pathogenshas been
suggested to show higher diversity in ectotherms than more traditional model
organisms, and therefore investigations in fishes, amphibians, and reptiles
may prove fruitful. We studied complement activity in a snake (the
cottonmouth, Agkistrodon piscivorus) indirectly using a bacterial killing assay,
and tested the following hypotheses: 1) complement activity (percent plasma
bacterial killing) would vary according to in vitro incubation temperature,
predicting optimal temperature for killing capacity to be similar to the snakes
documented preferred body temperature (e.g., ~ 24C). 2) Complement
activity would vary among treatment groups of snakes exhibiting different
reproductive conditions. Specifically, we predicted that pregnant snakes
would have reduced bacterial killing capacity, consistent with studies of
mammals which have described reduced complement and inflammatory
responses in pregnant females. We discovered a statistically significant
positive correlation between bacterial killing capacity and incubation
temperature, suggesting a higher temperature for optimal complement
performance in this snake than its own preferred temperature usually allows.
In addition, we found significantly reduced complement killing capacity in
pregnant females relative to non-pregnant females. Together, these results
illustrate interesting ecological trends in this component of the snake immune
system, and underscore the importance of considering body temperature
when conducting ecoimmunological studies.
P2.64 GREEN, MH*; AHN, D-g; HO, RK; HALE, ME; Univ. of Chicago;
[email protected]
Assessing the function of larval zebrafish pectoral fins during slow
swimming
The biomechanics and neural control of vertebrate limbs have been subjects
of much recent interest. During low frequency (slow) swimming, 5 day old
larval zebrafish execute alternating pectoral fin beats coupled with tail beats.
Here we extend our previous description of the kinematics and dynamics of
the slow swimming gait using computational techniques and flow
visualization. We describe the phase relationship between pectoral fin
oscillations and axial curvature, which better reflects the timing of
motoneuron input to axial muscle. In addition, we describe the swimming
performance of an fgf morpholino (finless) larval fish, which lack pectoral fins,
using a suite of kinematic parameters including swimming frequency, tail
beat amplitude, head yaw, midline curvature, forward velocity, swimming
episode length, distance traveled, and the advance ratio, a measure of tail
beat efficiency. Flow visualization indicates that the pectoral fins of wild type
larval zebrafish move water from anterior to posterior during slow swimming
and thus may be involved in producing thrust or stabilizing force. However
we find similar advance ratios and axial swimming kinematics in finless and
wild type fish. It is possible that the larval pectoral fins are important for
aspects of kinematics that we have not yet assessed; alternatively, this
fin-axis coordination may represent a coordination pattern that is important
for function in slow swimming later in the larval stage or in a different
behavioral context.
e237
P3.96 GREENLEE, Kendra J.*; VISHNUVARDHAN, Smitha; TOTH, Andy;
North Dakota State University, North Dakota State University, F, University of
Wisconsin, Superior; [email protected]
Identification of matrix metalloproteinases in the tobacco hornworm,
Manduca sexta
Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases
which function to break down various extracellular matrix proteins. The
degradation by these proteinases contribute to damage resulting from
chronic inflammatory diseases such as arthritis, asthma, and even tumor
progression. However, MMPs are also important for proper function of the
innate immune system. Larval Manduca sexta, the tobacco hornworm, are a
good model organism for studies of innate immunity due to their large body
size and hemolymph volume. While two MMPs have been characterized in
Drosophila and one has been recently identified in the wax moth, Galleria
mellonella, the function of MMPs in insects is relatively unknown. Our
hypothesis is that MMPs are important for immune function in M. sexta. To
begin testing this hypothesis, we first used degenerative primers to isolate
MMP from the fat body of 5th instar caterpillars. We obtained a partial
sequence that is 86% similar to MMP-1 in G. mellonella and 93% similar to
the putative MMP-1 in the silkworm, Bombyx mori. The homology shared
between our gene and MMPs in closely related species, as well as the
presence of the highly conserved catalytic zinc-binding region, indicate that
the gene we sequenced is an MMP. We predict that this MMP is expressed
in immune-related tissues and cells and is upregulated during infection.
P1.76 GROSS, T.N.; MANZON, R.G.*; Univ. of Regina, Biology;
[email protected]
Identification and characterization of developmentally regulated serum
thyroid hormone distributor proteins in sea lamprey, Petromyzon
marinus.
The lamprey appears to be the one vertebrate that contradicts the
well-established anuran model of an increase in thyroid hormone (TH)
concentrations initiating and driving metamorphosis. Previous studies have
shown that unlike other vertebrates, goitrogen-treated larval lamprey
undergo precocious metamorphosis, whereas, exogenous TH-treatments fail
to induce metamorphosis. By identifying changes in the patterns of sea
lamprey serum thyroid hormone distributor proteins (THDP) and their
affinities for THs throughout development, we hoped to clarify if this
difference is in part a physiological phenomenon related to TH availability or
a fundamental difference in the role of THs in lamprey metamorphosis. The
sea lamprey has four developmentally regulated serum THDP. The
albumin-like glycoprotein AS is the dominant THDP in the sera of larval and
metamorphosing phase sea lamprey. In stage seven of metamorphosis,
three additional THDP appear, including the albumin-like SDS-1
glycoprotein, the glycolipoprotein CB-III, and an unidentified low molecular
weight protein temporarily entitled Spot-3. In sera of parasite and spawning
phase lamprey, SDS-1, CB-III are the main THDP. Despite the shift in the
number and type of THDP densitometric and statistical analyses indicate
there is only a marginally significant difference (p = 0.049) in total serum T4
and T3 binding capacities between sea lamprey phases. Lastly, preliminary
data suggest that all four THDP bind T4 and T3 with similar affinities.
P1.126 GROVE, T.J.*; SMITH, S.B.; FORT, T.J.; Valdosta State University;
[email protected]
Sequence Comparison of the Calcium-Binding Protein Calsequestrin
from Poikilothermic Killifish Species
Isoforms of the sarcoplasmic reticulum (SR) calcium-binding protein
calsequestrin (CSQ) are differentially expressed in fast twitch skeletal muscle
(CSQ1) and slow twitch skeletal and cardiac muscles (CSQ2). CSQ
regulates calcium (Ca2+) release from the SR, enabling muscle contraction
and relaxation to occur without a cycle by cycle decline in force development.
Upon binding (and releasing) Ca2+, CSQ undergoes dramatic conformational
changes. The mechanisms by which this structurally dynamic protein is able
to undergo these changes and remain functional under variable physiological
temperatures are not known. Killifish are small intertidal fish adapted to the
wide variety of thermal environments observed in the coastal waters of North
America. Fundulus heteroclitus populations are exposed to different mean
annual temperatures along a latitudinal cline (1 o per degree latitude) and
rapid fluctuations during tidal cycles (up to 15oC in less than an hour). Two
congeneric species, F. grandis and F. similis, are found in the warm
(22-26 o C) coastal waters of eastern Florida and Gulf of Mexico. Partial
sequences of putative CSQ have been identified from fast twitch muscle of F.
similis and F. heteroclitus and two putative isoforms have been identified
from F. grandis, CSQ-A and CSQ-B. Analyses of deduced amino acid
sequences indicate that CSQ from F. heteroclitus, F. similis and CSQ-A from
F. grandis are highly conserved showing 94-98% identity (98-100%
similarity). The putative CSQ-B isoform from F. grandis is less conserved
when compared to CSQ from other Fundulus CSQ sequences, showing
58%-64% identity (77-79% similarity). Research is continuing to obtain full
length sequences of these putative CSQ isoforms. Supported by NSF
IOS-0817805 to TJG and TJF.
P2.1 GRUNERT, B; HUMFELD, S*; GERHARDT, C; University of Missouri;
[email protected]
Temperature-dependent preferences for advertisement-call frequency
in females of Hyla versicolor
Global climate change has the potential to impact many components of
biological systems, including the behavior of various animal species.
Ectothermic animals face an interesting communication challenge, in that
ambient environmental temperatures can significantly impact characteristics
of the species-specific advertisement call. Male treefrogs produce loud and
persistent acoustic signals called advertisement calls to attract mates. The
mate-choice preferences of female gray treefrogs (Hyla versicolor) have
been extensively studied, and it has been found that females tested at 20 C
prefer calls with standard bimodal frequency peaks of 1.1 + 2.2 kHz over
calls with higher and lower frequencies. However, we do not know how this
preference might be affected by temperature. To determine whether acoustic
preferences based on frequency are temperature-dependent, I collected
female frogs during their breeding season and tested their preferences in a
temperature-controlled anechoic testing chamber. I generated ten different
computer-synthesized advertisement calls that ranged in frequency between
0.55 + 1.1 kHz and 1.5 + 3.0 kHz. In two-speaker choice tests conducted at
three different temperatures (15 C, 20 C and 25 C), I observed the choice
(moved within 10 cm of a speaker) females made between a call with
standard frequency peaks of 1.1 + 2.2 kHz and one of the nine alternative
calls. Preliminary results indicate the preferred frequencies appeared to
remain at 1.1 + 2.2 kHz at lower temperatures. However, at higher
temperatures, female frogs were more likely to approach high-frequency
calls. These results will be discussed in the context of well-known
temperature-dependent physiological processes in the inner ear of frogs.
e238
P2.86 GUTIERREZ, J.*; SOTO, W.; NISHIGUCHI, M.K.; New Mexico State
University; [email protected]
Genetic temporal change in the bacterial symbiont Vibrio fischeri
isolated from natural host squid populations of Euprymna tasmanica
(Mollusca: Cephalopoda)
Vibrio fischeri is a bioluminescent bacterial symbiont of sepiolid squids
(Cephalopoda: Sepiolidae) and monocentrid fishes (Actinopterygii:
Monocentridae). Vibrio bacteria are transmitted environmentally; that is, they
are obtained from the surrounding seawater subsequent to hatching. The
infection is highly specific; only species from the genera Vibrio are capable of
fully infecting E. tasmanica juveniles. Previous results have shown that
although this association is stable, numerous V. fischeri strains are capable
of infecting populations of the same species of sepiolid from different
biogeographic locations. Thus, in an effort to provide insight into the factors
that drive the evolution and biogeography of this symbiosis, we have isolated
V. fischeri from E. tasmanica collected from the same wild populations
between 2000 and 2008. Genomic DNA was extracted from these isolates
and analyzed by PCR amplification and sequencing of the glyceraldehyde
phosphate dehydrogenase subunit A (gapA) locus. Identification of
population changes with this nine-year span represents over 16,000 bacterial
generations. Results obtained from our analysis provide detailed information
regarding the rate at which evolution has occurred in natural populations of
symbiotic V. fischeri. Thus, our findings will establish a baseline that can be
incorporated in future genetic analyses of symbiotic strains experimentally
evolved under various abiotic conditions such as salinity and temperature
that mimic ecological parameters found in nature, allowing further predictions
of speciation in the Vibrionaceae.
P3.205 GUTOWSKI, J.; WOJCIECHOWSKI, M.S.*; Nicolaus Copernicus
University, Torun, Poland; [email protected]
Energy metabolism, body temperature and non-shivering
thermogenesis in bats acclimating to simulated winter conditions.
To test the predictions that 1) bats decrease their lower critical temperature
(T lc ) in response to seasonal changes in ambient conditions, and 2) that
winter-acclimated bats increase their capacity for non-shivering
thermogenesis (NST), we measured metabolic rate (MR), body temperature
(Tb) and NST in 6 Myotis myotis during acclimation to simulated changes in
ambient conditions. MR (VO2 by indirect calorimetry) and Tb were measured
simultaneously at ambient temperatures (T a ) between 5 °C and 38 °C.
Capacity for NST was measured at T a =20±2 °C following injection of
noradrenaline (NA). The same individuals were tested in autumn, winter and
spring. In autumn and spring, bats were housed indoors, in flight cages and
fed daily ad libitum; the photoperiod was natural. In winter, bats hibernated in
an artificial hibernaculum and were fed every five days. The bats' resting MR
did not change with season (F(2,16)=1.63, p>0.05, 7.21±0.80 mWg -1 ).
However, mean euthermic T b decreased from ~36.6 °C and ~37.0 °C, in
autumn and spring, to ~36.1 °C in winter (F(2,66)=4.51, p<0.05). This
resulted in winter Tlc dropping by ~4 °C and ~2 °C compared to autumn and
spring, respectively. VO2 following NA did not change, but maximum Tb was
higher after NA injection in winter and in spring than in autumn
(F(2,20)=4.81, p<0.05). Our data suggest that in winter M. myotis saves
energy by lowering its euthermic T b . Higher maximum T b following NA
injection indicates increasingly effective use of NST. The changes also
indicate frugal energy expenditure during intra-hibernation euthermic
episodes.
P2.110 HACISKI, S. Insley*; WEBB, Jacqueline F.; University of Rhode
Island; [email protected]
Preliminary observations on the development of the little skate,
Leucoraja erinacea, with reference to the mechanosensory lateral line
system.
The development of the elasmobranch lateral line system has been studied
in only a few species, with papers published just twice in the past 100 or so
years, and has not been studied in detail in batoids. Here, the development
of the little skate, Leucoraja erinacea, is described as a basis for the study of
the development of its lateral line system. Adult skates, which readily lay
eggs in captivity, were maintained in tanks with recirculating seawater at
15-16C. Eggs laid in Dec. 2007 were candled and embryos were fixed in
10% formalin in PBS over several months. Another eight eggs, laid on known
dates (Jan.-May 2008), were sampled periodically to begin to generate a
developmental series for more detailed analysis. Results showed that in 38
individuals (49-91 mm TL) both disc width (DW) and tail length (TL) scale
positively with increasing total length (TL). Paired somites and tail bud were
visible at 4.5 mm TL (14 days post-deposition [dpd]). Pharyngeal arches
were visible at 6 mm TL (18 dpd). External gills were visible at 25 mm TL and
were resorbed at 73 mm TL. Early stages of the hyomandibular and scapular
lateral line canals were visible in a 50 mm TL embryo. The pectoral fins were
partially fused to the rostrum in a 42 mm TL embryo and remain caudal to
the mouth until fusion was complete at 50 mm TL. A cleared and stained
hatchling (93 mm TL, day of hatch) revealed what appears to be a complete
dorsal and ventral lateral line canal system indicating that canal
morphogenesis occurs prior to hatching. Further details of lateral line
development will be studied using histological analysis and SEM in order to
determine the timing of neuromast differentiation, ontogenetic trends in
neuromast size and shape, and the timing and pattern of lateral line canal
morphogenesis.
P1.43 HAIGLER, B.; ECKERD, M.S.; MARTIN, V.J.*; Appalachian State
University, North Carolina; [email protected]
Determination of the Optimal Housing Conditions for Box Jellyfish
Box jellyfish, phylum Cnidaria, are currently being studied for a variety of
reasons ranging from the evolutionary history and structure of
photoreceptors to anti-venom and protein-based toxins. The economic
impact of recent increases in jellyfish blooms worldwide underscores the
need to understand the life cycle and habitat preferences of the box jellyfish.
Little is known concerning long term husbandry of the box jellyfish. This
study is designed to determine the optimal housing conditions to promote
and sustain a healthy box jellyfish colony in the laboratory. Variables
analyzed include continuous water movement and water filtration versus still
unfiltered sea water changed weekly, water kept at 22 degree C versus
water kept at higher temperatures, light/dark cycle of 14:10 versus natural
day length, twice a week feeding regime versus once a week, and
comparison of natural filtered seawater to commercially available Instant
Ocean. Box jellyfish (Carybdea marsupialis) polyps were seeded on PVC
pipes in BiOrbs, round aquaria made of Plexiglas acrylic with a filter system,
and also placed in Pyrex dishes or Petri dishes. The number of polyps and
free swimming jellyfish were recorded daily in the BiOrbs, Pyrex dishes, and
Petri dishes to determine the effects of the variables on the viability of the
box jellyfish population. Results indicate that continuous water movement
and water filtration in the BiOrbs promote increased polyp budding and
jellyfish formation over budding rates observed in Pyrex dishes or Petri
dishes. Changing feeding and temperature regimes also affects budding
rates.
e239
P1.168 HAMILTON, R.A.*; JAYNE, B.C.; University of Cincinnati;
[email protected]
Arboreal Habitat Structure Affects the Choice of Routes by Rat Snakes
Recent studies of arboreal vertebrates, including snakes, have found that the
speed and difficulty of movement may be affected by: 1) the diameter and
incline of individual branches, 2) the clutter and turns created by secondary
branches, and 3) the gaps between different branches. Even though many
snake species are arboreal, no previous study has determined whether or
not they can perceive relevant structural variation of the habitat and respond
by selecting a route that is most likely to enhance locomotor performance.
Thus, we tested whether or not varying the gap distance and attributes of two
(destination) perches on the far side of a crossable gap affected the route
traveled by fifteen similar sized snakes belonging to two species of North
American rat snakes (Elaphe [Fitzinger, 1833]), which are proficient climbers.
For two destination perches with a 45 degree turn in a horizontal plane,
snakes preferred to cross the shorter gap, but the strength of the preference
for shorter gaps decreased when the difference in the gap distances
decreased. The snakes were able to perceive gap distances differing by less
than 7%. For perches that were within a horizontal plane, the snakes strongly
preferred (93% of the time) going straight rather than crossing an equal
distance (40 cm) gap with a 90 degree turn. However, decreased gap
distance could override the preference for going straight. Additional factors
such as the complexity of branching of the destination perches also resulted
in non-random path choice. Thus, biases in the choices between alternative
paths indicate both a sensory ability to perceive some subtle structural
variation and an overall ability to select routes that optimize the mechanical
benefits for locomotor performance.
P3.91 HAMPTON, P M; University of Louisiana, Lafayette;
[email protected]
Does prey envenomation improve digestive performance in
Agkistrodon piscivorus?
Pitviper venom is a combination of neurotoxins and proteolytic enzymes. It
has been hypothesized that the tissue-destroying qualities of crotaline venom
have evolved to enhance the digestion of large prey in cool environments, in
which ingested prey may putrify and kill the predator before digestion is
completed. The results of previous experiments intended to test this
hypothesis have been contradictory and inconclusive. Recently, a thorough
study found no effects of venom on specific dynamic action or gut passage
time. In the experiment relatively small prey were provided as meals with
ambient temperature equal to or above preferred activity temperature for the
species. When large prey are consumed and ambient temperatures are
sub-optimal venom may significantly enhance prey digestion. I am studying
the effects of pitviper venom on the post-prandial metabolic rate and gut
passage time in cottonmouth snakes (Agkistrodon piscivorus) provided large
meals and sub-optimal temperatures. Specifically, I am measuring
post-prandial oxygen consumption by the snakes after they have eaten rats
injected with reconstituted lyophilized A. piscivorus venom (experimental
animals) or injected with saline solution (control animals). I expect that
envenomated prey will be digested faster and will elicit a lower cost of
digestion (specific dynamic action) than prey that are not envenomated.
P3.173 HANES, S.D.*; KEMPF, S.C.; Auburn University;
[email protected]
Investigations of structural dynamics during bleaching in two species
of anemone, Aiptasia pallida and A. pulchella.
Bleaching involves the loss of symbiotic algae from cnidarian tissues and
may be a combined stress response of host and algae. There is little known
of structural changes that occur at the interface between symbiont-containing
endodermal cells and surrounding tissues during the bleaching process. In
this study, light and transmission electron microscopy are utilized to examine
histology/ultrastructure of two model organisms, Aiptasia pallida and A.
pulchella under both symbiotic and aposymbiotic conditions. Histological
observations reveal that symbiont-containing, endodermal epithelium exhibits
either simple cuboidal or columnar cell types, varying at different locations
within the anemone. Alternatively, aposymbiotic anemones display simple,
cuboidal endodermal cells throughout, but further ultrastructural examination
is necessary. These results suggest that different regions within the
anemone are lined with different types of epithelial cells, and may indicate
that metaplasia, or cell type transformation, is occurring. Additionally, factors
such as symbiont number and/or external conditions (i.e. light intensity) may
influence epithelial type and possible cellular transitions. Preliminary
ultrastructural results indicate the presence of previously undescribed cells or
cell processes, located between the basal host endodermal cell membrane
and the mesogleal layer. This suggests that reported host cell detachment
during bleaching involves more than simple release from the mesoglea.
Future investigations will be conducted to progressively examine endodermal
epithelia while thermal bleaching occurs.
P2.71 HANKE, W.*; LAUDER, G.V.; Harvard University;
[email protected]
Fish schooling: Measurements of Flow, School Structure, and Tail Beat
Frequency
Fish can aggregate into groups known as shoals or, in the case of
synchronized and polarized swimming behavior (Pitcher and Parrish, 1993),
schools. More than half of the 30000 fish species known form schools at
least at some point in their ontogeny. Our previous work has shown that
hydrodynamic energy savings do not generally play a significant role in the
formation of schools, contrary to the hydrodynamic hypothesis formulated by
Weihs (Nature, 1973). However, a reduced tail beat frequency of the fish in
the back of a school as compared to those in front has repeatedly been
reported and has been interpreted as a sign of energy savings (Herskin and
Steffensen, J. Fish. Biol. 1998; Svendsen et al., J. Fish. Biol. 2003). Here we
present data from three species of fish (Devario aequipinnatus, Fundulus
delineatus and Lepomis gibbosus) that do not show a reduced tail beat
frequency of the fish in the back of a school. We suggest an explanation for
the earlier, contradicting results based on wall and ground effects.
Furthermore, we quantified the tail beat phase relations between individual
fish in our schools and found that they were not fixed, as would be expected
in case of a strong influence of the wake of a fish on a following conspecific.
We confirm our conclusion that hydrodynamic effects have not been the
driving force in the development of fish schooling. Furthermore we review the
literature once more and raise some methodological concerns about
experiments that have measured the actual endurance of single swimming
fish versus groups.
e240
P3.46 HANSEN, H.*; SCHWARTZ, M.L.; Seattle University;
[email protected]
Fine structure of pigment cup ocelli in Micrura verrilli (Nemertea)
Most benthic nemerteans possess the ability to sense and respond to light
and have evident ocellar structures. However, the fine structure of
nemertean eyes has been studied only in two closely related species, which
revealed microvillar photoreceptive cells within a pigment cup. The
nemertean Micrura verrilli bears, anteriorly within the head, two prominent
orange bulbs thought to be ocelli, although histological sections have been
inconclusive. We examined these bulbs with transmission electron
microscopy and show that each is a pigment cup ocellus directed anteriorly
and that each photoreceptor cell has an apical crown of microvilli within the
cup. These results accord with observations that newly hatched juveniles
posses a pair of small orange-pigmented ocelli.
P3.108 HARMON, Shane; VICK, Mike; TRITLE, Brandon; BURTON,
Patrick*; Wabash College; [email protected]
Cell Death and Division during Regeneration in the Sea Anemone
Nematostella
While embryogenesis is a universal feature of animals, many metazoans
(e.g. cnidarians, echinoderms, annelids, flatworms, and select vertebrates)
are also capable of producing their adult body plans via regeneration. The
widespread ability of animals to undergo multiple developmental trajectories
suggests that such flexibility may have played a key role in metazoan
evolution. The cnidarian sea anemone Nematostella vectensis is an
emerging model system capable of embryogenesis, asexual development
and complete bidirectional regeneration. In order to compare the
mechanisms of regeneration to other model systems, we have investigated
the processes of both cell division and apoptosis during regeneration.
Widespread cell division is initially observed following injury. As regeneration
proceeds, cell division becomes restricted to the area surrounding the
wound. Similar to cell division, apoptosis levels increase throughout the body
following injury. However, unlike cell division, apoptosis does not appear to
localize near the injury. These results are consistent with an epimorphic
mode of regeneration in Nematostella.
P3.128 HARN, L.J.*; HAUSSMANN, M.F.; MAUCK, R.A.; Kenyon College,
Gambier, OH, Bucknell Univ., Lewisburg, PA; [email protected]
Don't count your chicks before they hatch: an experimental
manipulation of incubation effort in Leach's storm-petrel
(Oceanodroma leucorhoa)
Parents must allocate available energy between the competing demands of
self-maintenance and offspring care. Long-lived species such as Leach's
storm-petrel (Oceanodroma leucorhoa) may invest preferentially in
self-maintenance because any one reproductive event comprises only a
small proportion of lifetime reproductive success. Recently, our lab has
shown that sex of storm-petrel individuals may also influence allocation of
resources, since females invest energy into egg production while males may
expend more energy during incubation and chick rearing. During the early
incubation period we increased the energetic cost of flight by trimming the
outermost 1.5 cm of the primary remiges for one, both, or neither member of
breeding pairs. We used length of the incubation period and egg neglect as
measures of parental effort and the re-growth rate of an induced outer right
rectrix as an index of energy allocated to self-maintenance. Mean feather
growth rates for breeding pairs were positively correlated with length of the
incubation period (P=0.009). However, incubation length, individual feather
growth rate, and mean feather growth rate were not affected by Julian lay
date (P= 0.7) or experimental group (P > 0.5). Preliminary analyses of
known-sex individuals indicate that feather growth rate did not differ by sex
(P=0.18). Feather growth rate for sham treatment individuals (0.86 +/- 0.07
SE mm/d) did not differ significantly (P=0.15) from that of trim treatment
individuals (1.01 +/- 0.07 SE mm/d). Analysis of iButton temperature and PIT
technology data will allow us to assess the relationship between incubation
period, individual attendance patterns, egg neglect, and feather growth.
P2.33 HARRISON, J.S.*; BURTON, R.S.; Georgia Southern University,
Statesboro, Scripps Institution of Oceanography, La Jolla, California;
[email protected]
Sex-biased gene expression in the intertidal copepod Tigriopus
californicus
The intertidal copepod Tigriopus californicus has become an exciting system
to investigate the genetics of population structure and outbreeding
depression. Recent studies in this species suggest that the detrimental
effects of hybridization between genetically differentiated populations are not
always expressed equally in both sexes. In fact, little is known about the
genetic, and/or physiological differences between sexes of this copepod
species; the mechanism underlying sex determination itself remains
undetermined. Here we use a custom 2000 feature cDNA microarray to
investigate patterns of gene expression in males and females of T.
californicus. The main objective of this study is to characterize differences in
the transcriptome between sexes. Using conservative criteria in our analysis,
17.2% of the ESTs exhibited sex-biased expression levels (a minimum
estimate). Of the ESTs showing sex-biased expression, 58.6% were
expressed at a higher level in females and 41.4% were expressed at a
higher level in males. The ESTs showing the highest levels of differential
expression were strongly biased in the female direction, while those showing
lower levels if differential expression were partitioned equally between the
sexes. Similar to studies in other arthropods, a high proportion of female
biased genes fell into two general functional groups; 1) protein processing,
and 2) RNA/DNA processing. However, genes functioning in innate immunity
such as those involved in antimicrobial response also showed strong female
biased expression. The suite of ESTs showing male biased expression was
largely dominated by genes involved in muscle function and development.
e241
P1.1 HARTKE, T.R.*; ROSENGAUS, R.B.; Northeastern University, Boston;
[email protected]
Opening the Black Box of Colony Foundation in a Polygamous Termite
Most termite colonies are founded by a monogamous pair (king and queen)
following the dispersal flight, but a few species have variable breeding
strategies whereby new colonies may be founded by multiple queens and/or
kings. About one-third of mature Nasutitermes corniger colonies are headed
by multiple queens and/or kings; two-thirds of those bear genetic hallmarks
of foundation by non-relatives. Little is known about the incipient stage of
colony development, or the costs and benefits of polygamous versus
monogamous founding in termites. In the present study, laboratory and field
studies were undertaken to open the black box between dispersal of
reproductives and appearance of young arboreal colonies. Nest-collected N.
corniger alate reproductives were collected in and around Gamboa and
Galeta, Panama. Between 2006 and 2008, 5,372 experimental incipient N.
corniger colonies were established in the lab, while manipulating group size
(pairs, trios, quintets) and origin of founders (nestmates, non-nestmates).
Incipient colonies were censused daily for 120 days to record demographic
information: deaths of founders, first appearances of eggs, larvae, workers,
and soldiers. Naturally-established incipient colonies from the field were
preserved and analyzed to compare their demographics with those of
lab-established colonies. Data from the field appear to be consistent with
laboratory results. Results from mesocosm experiments indicate that
additional reproductives may be accepted during colony foundation, while
preference for group or pair founding could depend on colony of origin.
P2.98 HAUGHEY, Michael/D*; GREEN, Steven; LOGAN, Michael; BOBACK,
Scott; MONTGOMERY, Chad; Salem State College, University of Kent,
Canterbury, Univ. of Texas, Arlington, Dickinson College, Truman State
University; [email protected]
A Comparison of Body Size and Condition of Boa constrictor imperator
on the Cayos Cochinos Archipelago
The islands of Cayo Pequeno and Cayo Grande within the Cayos Cochinos
archipelago of Honduras each support dwarfed populations of Boa
constrictor. Despite their close proximity (< 1 km), these islands differ in
habitat structure, potential prey species, and prey availability. For instance,
populations of Agouti paca, Dasypus novemcinctus, Dasyprocta punctata,
and Rattus rattus occur solely on Cayo Grande. On Cayo Pequeno, B.
constrictor are known to prey (almost exclusively) upon lizards and migratory
birds, prey that are generally much smaller than the mammals found on
Cayo Grande. We predicted that these differences in prey availability and
diversity would result in differences in mean snout-to-vent-length (SVL),
mass, and body condition between boa populations. The residuals from a
linear regression of LogMass verse LogSVL were used as an index of body
condition. Contrary to our hypothesis (for both males and females), SVL
(P=0.157), mass (P=0.367) and body condition (Male P=0.068 Female
P=0.315) did not differ between Cayo Pequeno and Cayo Grande. This
suggests that, despite differences in prey availability and diversity, snakes
are maintaining similar body sizes and conditions. Interestingly, despite a
lack of difference in overall body size and condition between males and
females between islands, B. constrictor on Cayo Grande were found to
display a greater degree of sexual size dimorphism than those on Cayo
Pequeno (SVL, P=0.034 Mass, P=0.037).
P2.76 HAYASHI, M*; FEILICH, KL; ELLERBY, DJ; Wellesley College;
[email protected]
The mechanics of explosive seed dispersal in Orange jewelweed
Explosive dehiscence aids seed dispersal in a number of plant species.
Orange jewelweed (Impatiens capensis, Meerb.) is an herbaceous annual
exhibiting this type of dispersal mechanism. High speed video analysis was
used to determine the sequence of events during seed release in this
species. Longitudinal splitting of the pod into 4 rapidly coiling segments
launched the seeds. Splitting and coiling took 4.2 +/- 0.4 ms (mean +/- SEM,
N = 8). Stored elastic energy as a result of turgor pressure is the likely
driving force behind rapid plant movements. Isolated coils were attached to
an ergometer and their stress-strain relationships were determined. Stress
increased with coil hydration, confirming the role of turgor pressure. The
energy storage capacity of the coils was 124 +/- 37 J/kg (mean +/- SEM, N =
8), similar to that of spring steel. Analysis of the kinetic energy of the
launched seeds will determine the effectiveness with which stored elastic
energy is transferred to the seeds.
P3.18 HAZARD, L.C.*; KWASEK, K.M.; Montclair State Univ., NJ;
[email protected]
Effects of road deicers on survival and behavior of larval and adult
wood frogs
Use of road deicers (primarily NaCl) in the northeastern U.S. has increased
dramatically over the last century. Salts applied to roads can travel
considerable distances from the site of application, and may contaminate
local watersheds to levels above 100 mM. Amphibians that breed in vernal
pools early in the spring, when salt levels could still be high, may be
especially vulnerable to increased salinities. We integrated responses of
larval and adult wood frogs (Lithobates sylvaticus) to increased salinity to
determine whether adult frogs would be able to detect and avoid salinities
that would be detrimental to them or to their offspring. Tadpoles were raised
in groups at concentrations ranging from 0-200 mM NaCl. No tadpoles at
higher concentrations survived to metamorphosis. At low salinity, tadpoles
had slightly higher mortality and lower growth and development rates than
control animals. Adult frogs were mildly dehydrated to induce thirst, then
placed in a shallow dish of water ranging from 0-500 mM NaCl. Location (in
or out of the dish) and behavior (moving, standing, sitting, or water
absorption response) were recorded during a 10-minute trial. In contrast to
arid-adapted anuran species, the wood frogs showed no aversion to salt,
remaining in even 500 mM NaCl for the full 10 minutes. Mass loss during the
10-minute trials increased with increasing salinity. The results have important
ecological implications. Tadpoles showed sublethal effects even at relatively
low concentrations and high mortality at higher concentrations, but adult
wood frogs may not be capable of evaluating the salinity of potential
breeding sites, leaving this species potentially vulnerable to increased
mortality or subtler sublethal effects due to road salt runoff.
e242
P3.30 HEINRICH, Erica C.*; HARRISON, John F.; Arizona State University;
[email protected]
Critical periods for oxygen effects on adult size in Drosophila
melanogaster
In many organisms, including humans, lowered oxygen concentrations have
been seen to have an effect on development and adult size. In previous
studies, it has been shown that flies reared in hypoxia are significantly
smaller than those reared in normoxia. However, the mechanism which
creates this size effect remains unknown. If oxyen effects on size occur
during a specific developmental stage, this would narrow down the possible
pathways responsible for the oxygen effect on size. Prior studies have
suggested that the pupal phase may be critical for oxygen effects on body
size in fruitflies. We examined this question by rearing flies in normoxia (21%
oxygen) except for specific 24 hour time periods when atmospheric oxygen
level was changed to 10% oxygen. We also conducted the converse
experiment. We hypothesized that the late larval would be particularly
oxygen-sensitive as that is when most mass is gained, and that the early
pupariation stage would also be very sensitive as this is when the adult
cuticle is formed. However, fly size was significantly affected by oxygen (by
about 6%) no matter at what point during development that the atmospheric
oxygen was switched, including the egg stage. Therefore, either there are
multiple independent mechanisms by which oxygen affects size (e.g.
suppression of feeding during the larval stage, effects on cuticle cell size in
the pupal stage) or there is a developmental pathway mediating oxygen
effects on size available at all times during development . The effects of egg
oxygen level on adult size are particularly intriguing, as they suggest that
oxygen effects on the embryo organ and body sizes of adults This research
was supported in part by funds from the ASU School of Life Sciences and
the Howard Hughes Medical Institute through the Undergraduate Science
Education Program and by NSF IBN 0419704 to JFH.
P1.142 HENRY, R.P.; Auburn University; [email protected]
A carbonic anhydrase repressor found in the sinus gland acts at the
level of mRNA expression in the euryhaline green crab, Carcinus
maenas
The enzyme carbonic anhydrase (CA) is known to be a central molecular
component of branchial ion uptake mechanisms in crustacean gills.
Cytoplasmic CA catalyzes the conversion of respiratory CO2 and water to
protons and bicarbonate ions, which then serve as counterions for the active
uptake of cations (Na)and anions (Cl), respectively. In the euryhaline
decapod, Carcinus maenas,CA activity is induced up to 12 fold in the
posterior, ion-transporting gills, upon exposure to low salinity (15 ppt). CA
induction is believed to be under transcriptional regulation (i.e., gene
activation followed by synthesis of new enzyme). mRNA for the cytoplasmic
isoform (CAc) increases 10 fold after 6 hr of low salinity exposure and 100
fold after 24 hr. This precedes the initial induction of CA activity, which takes
place at 48-72 hr post-transfer. CA gene activation appears to be under the
control of a repressor found in the sinus gland (SG). Injection of SG extract,
twice per day over a 4 day period, into crabs transferred from 32 to 15 ppt,
results in an approximate 50% inhibition in the induction of CA activity.
Injection of extract of the surrounding medullary tissue of the eyestalk has no
effect. Hourly injections of SG extract for the initial 6 hours of low salinity
transfer inhibits the initial 10 fold increase in CAc mRNA by up to 70%.
These results indicate that the putative CA repessor acts at the level of gene
expression to maintain low, baseline concentrations of CAc mRNA and
hence baseline levels of CA activity in high salinity. Supported by NSF IBN
02-30005.
P1.65 HERNANDEZ, L. P.*; MORGAN, R. J.; George Washington Universty,
Washington, DC; [email protected]
Size and distribution of muscle fiber types within chondrichthyan
muscles
Vertebrate morphologists have long appreciated the importance of muscle
fiber type composition. Although they vary widely in their size and
distribution, different isoforms of slow and fast myosins comprise the bulk of
all skeletal muscle tissue. Combined, these different myosins coordinate to
perform a variety of important functions associated with locomotion, feeding
and breathing. Evolutionarily, amniotes and anamniotes have shown a
remarkable disparity in muscle fiber type distribution. In amniotes and adult
amphibians muscle fibers show a mosaic distribution with interspersed slow
and fast fibers. In fishes, as well as in larval amphibians, muscle fibers show
a zoned distribution whereby specific fiber types group together within
muscles. Here we describe the distribution and relative proportion of fast and
slow fibers in adult shark and skate muscles. Muscles were stained for a
variety of specific myosins using standard immunohistochemical methods.
Antibodies considered to stain all vertebrate myosins (based on data from a
large number of amniotes and anamniotes) did not recognize myosins within
many irregularly shaped muscle fibers in skate. While our results do not
indicate the mosaic pattern seen in amniotes, they also do not fully support
the strictly zoned fast and slow regions seen in most anamniotes. Antibodies
against slow myosin stained the peripheries of certain larger muscle fibers,
but stained entire smaller diameter fibers in other muscles as seen in
anamniotes. Thus skate muscles may be comprised of a number of
intermediate fiber types and consist of a unique pattern of distribution. It is
likely that a range of intermediate muscle fiber types may be an ancestral
character. We discuss the functional, evolutionary, and developmental
implications of our data.
P2.178 HEYLAND, A*; REITZEL, A; HODIN, J; U. of Guelph, Canada,
WHOI, USA, Hopkins Marine Station, USA; [email protected]
Thyroid hormone signaling in echinoderms: Comparative genomics,
cross-kingdom signaling and life history evolution
Hormones orchestrate life history transitions in animals and non-animals,
canonically via environmental inputs that directly or indirectly regulate
internal (endogenous) hormonal release and/or response. Less well studied
are cases in which the sources of the hormones themselves are external
(exogenous). One such example is echinoderms, where thyroid hormones
(THs) regulate metamorphic timing. In planktotrophic echinoderm larvae (i.e.
those that need to feed to complete metamorphosis), the primary source of
THs appears to be exogenous: they are derived from the unicellular algae
that these larvae consume. By contrast, lecithotrophic echinoderm larvae
(i.e. those that need not feed) apparently have a greater capacity for
endogenous TH synthesis. We have proposed that such variation in internal
hormone synthesis capacity may bias the evolutionary origin of lecithotrophy,
a developmental mode that has evolved repeatedly in echinoderms. First, we
will review what we know about THs in echinoderm development and
evolution, in the context of a general discussion of hormones and life history
evolution in multicellular eukaryotes. We will also report on our ongoing
measurements of THs from sea urchin developmental stages and unicellular
algae using HPLC coupled mass spectrometry. Lastly, we will discuss the
current state of knowledge regarding invertebrate TH signaling. Comparative
genomics and EST analyses have confirmed that many TH signaling
components are conserved among deuterostomes, and that orthologs of
vertebrate TH receptors are identifiable throughout the Bilateria. We will
describe our current research on TH signaling modalities and metabolism in
echinoids (sea urchins and sand dollars).
e243
P3.53 HITCHCOCK, Amanda C.*; PROPERT, Matthew W.G.; MARSH,
Richard L.; Northeastern University; [email protected]
Stability despite rapid large fluctuations in calculated net muscle
moment at the knee during normal level running in guinea fowl.
We calculated the net muscle moments at the leg joints of guinea fowl using
2-D inverse dynamics. Birds ran along a trackway and over a force plate.
Force plate data were synchronized with high-speed video recording of
markers, which allowed the calculation of the joint centers. These data along
with previously measured segment properties allowed the calculation of net
muscle moments and powers at all of joints in the limb. Generally, peak
moments at all joints were extension moments occurring during stance and
were highest at the knee and hip. However, at the hip and knee relatively
large moments are required in late swing due to the inertia of the limb
segments. At the knee this inertial moment is in flexion and it reaches a peak
near footdown, at which point it falls suddenly by 50 100% of the peak value
and then rises again to approximately its former value before switching to an
extension moment as stance proceeds. The sudden large drop and
restoration of the flexion moment occurs in approximately 20 ms for a full
cycle. During this time the knee joint angle is undergoing a stable flexion
trajectory, i.e., the knee appears highly damped. We hypothesize that the
large damping apparent at the knee is due to strong co-contraction occurring
in knee extensors and flexors in late swing and throughout stance.
Supported by NIH AR47337 and NSF IOB-0542795.
P1.13 HO, J.M.*; DEMAS, G.E.; Indiana University, Bloomington;
[email protected]
Endocannabinoid signaling and energy balance in Siberian hamsters
(Phodopus sungorus)
Maintenance of energy homeostasis is critical for all organisms and the
importance of understanding the control of energy balance is evident in the
face of the growing prevalence of human obesity. Siberian hamsters exhibit
marked seasonal changes in body weight and food intake, losing ~30% of
their body weight in short winter-like day length. Profiles of classical energy
balance genes, however, provide little explanation for these dramatic
changes. The endocannabinoid (EC) system has been noted for its influence
on appetite and energy expenditure, and a well-established literature
indicates these effects are mediated by the cannabinoid receptor, CB1. CB1
receptors are widely expressed in the brain and empirical data support the
involvement of hypothalamic areas in cannabinoid-induced eating. To date,
few studies have examined the influence of cannabinoids on energy balance
in a temporal context and no studies have examined EC signaling across
energetic state in Siberian hamsters. Thus, we examined seasonal changes
in EC signaling and its correlation with body weight in Siberian hamsters.
Specifically, we transferred hamsters from long day photoperiod (16 h light:8
h dark) to short day photoperiod (8 h light:16 h dark) and compared them to
long day controls at 0, 2, 6, and 12 weeks. Data will be presented on blood
EC levels as well as CB1 levels in brain nuclei involved in energy regulation
including those of the hypothalamus. The results of this study will contribute
to the general understanding of energy regulation. Because these animals
naturally fluctuate between energy states comparable to those of obesity and
leanness, they serve as an important model for studying the physiological
control of energy balance and may provide novel insight to energy regulation
not offered by non-seasonal rodent models.
P3.12 HOANG, L.K.*; MCCOY, K.A.; ST MARY, C.M.; GUILLETTE, L.J.;
University of Florida, Smithsonian Tropical Research Institute;
[email protected]
Renal pathologies in giant toads (Bufo marinus) vary across land-use
practices
Kidneys are the principle excretory organs for many vertebrates and
excessive or chronic exposure to exogenous toxins can lead to renal
pathologies and chronic renal failure. Although many studies have linked
exposure to specific chemicals (e.g., pesticides, pharmaceuticals) with
specific renal diseases, none compare renal pathologies occurring in wildlife
living in different types of human-dominated landscapes which have
characteristic chemical milieus. In this study, we use light microscopy to
characterize renal morphology and identify pathologies diagnostic of toxin
exposure in the giant toad (Bufo marinus) living in suburban and agricultural
habitats. We identify tubule and interstitial pathologies that have been
associated with toxicant exposure in other organisms, including humans.
Pathologies consistent with toxin-induced tubule disease were observed at
three sites (one suburban and two agricultural), whereas interstitial
pathologies were most severe at one agricultural site. Indeed, some of the
pathologies we identify are similar to those found in human drug abusers and
patients suffering medication-induced nephropathy. The mechanisms
causing differences in toxin-induced renal pathologies across sites and the
implications of these pathologies on wildlife health are unknown and warrant
further study. A more detailed understanding of the toxicological mechanisms
as well as the chemicals involved could help us devise strategies to avoid or
mitigate the impacts of toxins on humans and animals living in human
modified environments.
P3.123 HODIN, J*; MILLER, P; HUANG-VOSS, C; EPEL, D; Hopkins Marine
Station, Stanford University, CA, USA; [email protected]
Inquiry-based web curricula in development, microscopy, physiology
and environmental science
We are developing a range of inquiry-based, freely available biology
education resources distributed through several web sites. VirtualUrchin
(http://virtualurchin.stanford.edu) highlights sea urchins as fertile ground for
investigating core biological principals, applying the scientific method,
investigating environmental problems, and learning to use biology lab tools.
VirtualUrchin is a companion site to the very popular Sea Urchin Embryology
teacher support site (http://www.stanford.edu/group/Urchin). VirtualUrchin
features microscopy tools, with resource tutorials on the use and care of
microscopes, measurement of microscopic objects, and tools for comparing
specimens using different microscopic techniques. Our resources also
emphasize the usefulness of sea urchin development in studying
anthropogenic impacts on marine organisms, including pollution and ocean
acidification. Our third site (http://esi.stanford.edu), in cooperation with
Swedish universities, uses a CSI approach to engage students in an
investigation of why salmon have been disappearing during their migration
up the most productive salmon river system on the planet: Canada's Fraser
River. Students use interactive virtual tools to investigate salmon life cycles,
determine the destination of migrating salmon, observe changes in
respiration patterns, circulation, migration and energetics, and explore
general information on global climate change and its real-world impacts. All
of our projects are developed under the umbrella of the Virtual Labs project
at Stanford (http://virtuallabs.stanford.edu), where our resources are
compiled alongside a wide range of freely-available, high quality educational
resources in biology and biomedicine.
e244
P2.81 HOLGERSSON, M C N*; NICHOLS, W A; PAITZ, R T; BOWDEN, R
M; Illinois St. Univ.; [email protected]
Turtle gut microflora: initial acquisition
Adult aquatic turtles are host to an array of gastrointestinal bacteria,
including Salmonella spp. Conversely, it is thought that turtle embryos within
freshly laid eggs are sterile. While it is known that the external surface of
turtle eggs can acquire bacteria from the mothers cloaca during laying and/or
immediately thereafter via contact with bacteria laden nest substrate, the
mechanism by which developing turtles initially acquire these microflora is
poorly characterized. This study was designed to test the hypothesis that
developing turtles first acquire gut microflora during the hatching process via
ingestion of infected eggshell and not prior via eggshell penetration (as has
been previously suggested). Eggs from eleven clutches of Trachemys scripta
elegans (Red-eared slider turtle) eggs were divided into four incubation
groups: 1) natural, 2) Gentamicin treatment, 3) Gentamicin treatment
thereafter administered Salmonella (a stock acquired from our turtle
population), and 4) Gentamicin treatment thereafter administered Salmonella
and treated again with Gentamicin just prior to hatching. Gentamicin is a
proven antibiotic for eradicating bacteria from turtle eggs. The Salmonella
application served as a natural self-replicating indicator that could be quickly
detected via selective plating using XLT4 agar. Treatment groups were kept
separate under identical conditions in order to minimize the potential of
cross-contamination. Eggshell bacteria loads were characterized during and
after hatching; hatchling bacteria loads were characterized post-hatch via
excrement analysis and necropsy. We predicted that hatchlings from
treatments 2 and 4 would be free of Salmonella while treatments 1 and 3
would acquire Salmonella by ingesting infected eggshell.
P2.114 HOLLIDAY, Casey M; Marshall University; [email protected]
New Insights into the Mandibular Symphyses of Reptiles
The morphology of the mandibular symphysis likely reflects the functional
environment in which it resides and numerous analyses have focused on the
correlation between symphyseal structure and masticatory behavior among
mammals. However, few studies have investigated symphyseal evolutionary
and functional morphology among reptiles. Whereas turtles, birds, and
crocodilians have characteristically fused or interdigitated the symphysis,
lepidosaurs maintain open symphyses. To further illustrate structure-function
relationships of the joint, data on soft and bony tissues that comprise the
symphysis were collected among a diverse sample of extant lizards including
iguanians, geckos, skinks, and varanids using microCT scanning, followed
by standard and polarized light microscopy of undecalcified serial histological
sections. Among lizards, soft-biting taxa possessed mostly parallel-fibered,
elastic connective tissues whereas hard-biting taxa possessed significantly
more cartilaginous and mineralized tissues within the symphysis. Other
species displayed connective tissue morphologies within this spectrum and
histology suggests a three-dimensionally complex organization of tissues
including a laminar organization of loose parallel-fibered tissues,
cartilaginous domains and dense parallel and woven fibers. Some of these
fibers attach directly to Meckels cartilage whereas most are embedded as
extrinsic fibers within the bony symphysis. All species investigated rely on
soft tissues, rather than bony interdigitations, to support the joint. These and
other data provide the foundation to further explore the adaptive plasticity
and in vivo function of the joint among extant taxa as well test hypotheses of
the structures evolution among fossil taxa.
P1.144 HOLM, C.; KEACH, S.; BETKA, M.; HARRIS, H.W.; JURY, S.H.*;
MariCal Inc.; [email protected]
Cloning and Characterization of Crustacean Calcium-Sensing
Receptors (CaSRs)
Many marine invertebrates experience significant changes in the ionic
composition of environments they encounter during their life histories. In
terrestrial animals and fish, G-protein coupled receptors called
calcium-sensing receptors (CaSRs) have been identified as key regulators of
ionic and nutrient homeostasis. Recent genome projects, including those for
Ciona intestinalis and Strongylocentrotus purpuratus, have suggested CaSR
gene homologs are present in invertebrates (Loretz, 2008) but their possible
tissue specific expression is unknown. We report here the cloning of a
full-length CaSR gene from the lobster Panulirus interruptus (LobCaR), and
compare it to other known or putative CaSRs. Using CaSR specific
antibodies we also demonstrate the existence of CaSRs in other
crustaceans. The gene structure and sequence are highly conserved relative
to CaSRs from mammals and teleosts. Studies using anti-LobCaR antibodies
reveal that crustacean CaSRs are expressed predominantly in
osmoregulatory and calcium regulating tissues including antennal gland, gill,
and gastrointestinal tract. We conclude that CaSRs are expressed in lobsters
and likely play an integral role in multiple physiological functions in
crustaceans including nutrient and salinity sensing, calcium homeostasis and
biomineralization.
P1.7 HOOD, Wendy R*; HILL, Geoffrey E; Auburn University;
[email protected]
Dietary fat influences carotenoid-based coloration in the American
GoldfinchDietary
Yellow, orange and red ornamental coloration in vertebrates is often the
result of carotenoid-based pigments. Carotenoid pigments cannot be
synthesized by vertebrates de novo and thus carotenoids must be consumed
to be expressed. Carotenoid expression in bird feathers is
condition-dependent; color properties are correlated with total carotenoid
intake, total food intake, and parasite load. In several bird species, males
that express greater pigmentation have been shown to be preferred as
mates by females, so it is assumed that females assess male pigmentation
as an indicator of male condition. Carotenoids are fat-soluble pre-vitamins
that are efficiently absorbed across the gut epithelium when associated with
lipids in the intestinal lumen. Yet, little is known about the effect of dietary fat
on carotenoid absorption and color expression in birds that express
carotenoid-based ornaments. American goldfinches express bright yellow
body and dark orange bill coloration that are both carotenoid based. We
examined the effect of dietary fat on body and bill color expression American
Goldfinches maintained throughout the molt on diets with low (7%), moderate
(14%), or high fat (21%) but similar concentrations of carotenoids and total
energy. Treatment has no significant effect on feather coloration, but the hue
of the bill was greater (oranger) for animals consuming the 14% and 21% fat
diet compared to those consuming only 7% fat. These finding suggest the fat
content of diet plays a role in expression of carotenoid coloration in birds.
e245
P2.57 HOPKINS, B.A.*; HOMBERGER, D.G.; Louisiana State Univ., Baton
Rouge; [email protected]
The gular glands of Alligator mississippiensis condition the interscale
skin of the intermandibular and gular regions
Crocodilians swallow prey items that are large relative to their body size.
Swallowing large prey items requires an expansion of the pharynx and
esophagus and, thus, an expansion of the intermandibular and gular skin. In
the scaly skin of crocodilians only the soft interscale skin is stretchable and
pliable, and, therefore, needs to be conditioned to maintain its physical
attributes. In contrast to mammals, which condition their skin with sebum
from numerous and dispersed integumentary glands, alligators have only
three kinds of locally restricted integumentary glands, one which is a pair of
gular glands. The gular glands have been thought to produce pheromones;
however, their lipid secretion consists of many of the same components as
those found in cosmetic skin care products. In the alligator, deep stretchable
interscale skin grooves radiate rostrally from the orifice of the gular gland and
interconnect with smaller stretchable interscale skin grooves in the
intermandibular and gular regions. The interscale skin grooves form a
network of hierarchically arranged channels of particular width and
characterized by particular epidermal microstructures. The epidermal
microstructure of the stretchable interscale skin grooves varies significantly
from that of the less stretchable interscale skin in the abdominal region, but
bears some resemblance to the microstructure of the channels that carry
water from wet skin to the mouth of some desert lizards. We hypothesize that
the stretchable skin in the intermandibular and gular regions of alligators
serves not only to accommodate the passage of large prey items, but also to
channel and distribute skin conditioning lipids from the paired gular glands.
P2.58 HORTON, Jaquan M.*; GOSLINE, John M.; Univ. of California, Irvine,
Univ. of British Columbia; [email protected]
Fish have GUTS too: The material properties of the intestinal tissues in
teleost fishes
Durophagous fishes are predators that specialize in eating hard prey,
generally by crushing the shells of mollusks and crustaceans. Others have
investigated many of the mechanisms and morphologies that enable fish to
consume hard prey and exploit this trophic niche (e.g. dentition and cranial
specializations, bite force and mechanical advantages). However, few have
examined the effects of hard prey consumption on visceral tissues. If
indigestible shell or exoskeletal fragments are consumed, the material
properties of the intestinal tissues must withstand the potential mechanical
damage caused by sharp foreign bodies (e.g. shell shards) passing through
the gut. In this study, we test the hypothesis that the intestines of
durophagous fish are more extensible than fish that do not eat hard prey.
The whole intestines of six fishes were inflated using a custom,
static-pressure system to investigate their material properties. The J-shaped
stress-strain curves showed that the initial stiffness ranged from 6 to 60 kPa
and that the final stiffness ranged from 4 to 24 MPa. The maximal
extension-ratio of the inner lumen ranged between 3.5 and 10.9, and this
extension-ratio provides an indication of the size limit for an indigestible shell
item or processed unit of food that can travel down the intestine. This work
offers significant insight into the material properties of intestinal tissue in
teleost fishes. Future studies will focus on the possible adaptive properties of
teleost intestinal tissues in a phylogenetic context.
P3.206 HOUGEN, Helen Y*; HIEBERT, Sara M; Swarthmore College;
[email protected]
Effect of diets rich in saturated and polyunsaturated fatty acids on
performance of Mus musculus in warm and cold environments
The homeoviscous adaptation hypothesis predicts that cell membranes
should incorporate higher proportions of unsaturated fatty acids at lower
temperatures to counteract cold-induced increases in membrane viscosity
and thus to maintain membrane function. In a previous experiment in our
laboratory, the obligate homeotherm, Mus musculus, increased its
preference for a diet rich in polyunsaturated fatty acids (PUFAs) when
exposed to cold. However, cold-induced changes in diet preference over
three weeks were not associated with improved performance in the cold, nor
were there substantial differences in membrane composition after this
three-week period. In the current experiment, mice in each of three treatment
groups (N = 15 in each group) were fed a single diet [chow rich in n-3
PUFAs, in n-6 PUFAs, or saturated fatty acids (SFAs), respectively] for ten
weeks at 23 C. Grip strength, memory, and nocioception were then tested in
each diet group at 5 C and at 23 C; fatty acid composition of their
membranes was also assayed. While some trends were consistent with the
homeoviscous adaptation hypothesis, preliminary analysis showed no
significant effects of diet or temperature on most measures of performance.
Further studies are needed to determine the function of cold-enhanced
preference for PUFAs in this species.
P3.83 HRANITZ, J.M.*; SAVITSKI, A.N.; BARTHELL, J.F.; CLEMENT, M.L.;
SONG, D.S.; PETANIDOU, T.; Bloomsburg Univ. of Pennsylvania, Univ. of
Central Oklahoma, Edmond, Univ. of Central Oklahoma, Edmond, Univ. of
California, Berkeley, Univ. of Aegean, Mytilene, Lesvos (Greece);
[email protected]
Nucleotide Diversity in Native and Invasive Island Populations of the
Leafcutting Bee (Megachile apicalis)
Megachile apicalis is a solitary bee that rapidly invaded cavity-nesting bee
communities in the western U.S. during the 1980s. In the Central Valley of
California, M. apicalis appears more eurythermal than native megachilid
bees and, in addition to nesting in riparian zone and marsh habitats,
successfully reproduces in hot, dry grassland habitats that provide summer
conditions surpassing native bee larva stress tolerance. Such a broad range
of habitat use suggests that M. apicalis populations contain either a
generalist genotype or genetic variants suited for diverse habitats. To
compare the genetic diversity of invasive versus native M. apicalis, we
examined the genetic diversity of samples collected from an invasive
population on Santa Cruz Island (USA) and the Aegean Island of Lesvos
(Greece). Bees collected at two or three sites on each island were genotyped
for 658 bp of the cytochrome oxidase subunit I (COI) mitochondrial DNA
locus. Leafcutting bees on Santa Cruz Island carried identical COI
haplotypes whereas those on the Island of Lesvos yielded three COI
haplotypes. While samples from mainland populations may reveal different
results, similar samples of two island populations support the hypothesis that
invasive populations of M. apicalis have lower genetic diversity than native
populations of this species.
e246
P1.159 HUBB, A. J.*; KLOK, C. J.; HARRISON, J. F.; Arizona State
Univeristy, Arizona State University; [email protected]
Phenotypic placticity of body size in response to atmospheric oxygen
in Drosophila melanogaster
The concentration of oxygen in the atmosphere has strong effects on adult
body size in a variety of animals, including fruit flies, Drosophila
melanogaster. Prior experiments have indicated that lower oxygen levels
lead to linear decreases in the body size of fruitflies while hyperoxia (40%
oxygen) increases size. However, all of these prior studies have reared
fruitflies in bottles of fly populations, precluding clear differentiation of
phenotypic plasticity from evolution occurring within a single generation. To
address this concern, we reared fruitflies individually under 7 test oxygen
levels (10%, 16%, 21%, 24%, 27%, 31%, 40%) and measured adult mass.
Hypoxia suppressed body size, but body sizes of all flies reared at 21%
oxygen and above were identical. These data suggest that prior studies
indicating phenotypic plasticity of fly body size in response to hyperoxia may
have instead been indicative of rapid evolution. Supported by NSF
HRD-0114712 (WAESO at ASU) and NSF IOB-0419704 (JFH).
P1.135 HUGGINS, T.*; LICORISH, R.; CARROLL, M.A.; CATAPANE, E.J.;
Medgar Evers College, Kingsborough Community College;
[email protected]
p-Aminosalicylic Acid Blocks Manganese from Impairing the
Dopaminergic Innervation of the Gill of the Bivalve Mollusc,
Crassostrea virginica
Previous work in our lab showed that treating Crassostrea virginica for 3
days with µmolar concentrations of manganese (Mn) impaired the
cilio-inhibitory innervation of the gill which is mediated by dopamine neurons
originating from the cerebral and visceral ganglia of the animal. High levels of
Mn are neurotoxic to people and cause Manganism, a Parkinsons-like
disease. Clinical interventions for Manganism have not been successful.
Recently, p-aminosalicylic acid (PAS) was reported to provide effective
treatment of severe Manganism in humans. The present study sought to
determine if the effects of the 3 day treatments with Mn could be decreased
by cotreating animals with PAS. Animals were treated with Mn (500 µM),
PAS (50 and 500 µM), or PAS plus Mn, for 3 days. Control animals were
similarly treated without Mn or PAS. Beating rates of the lateral cilia of gill
epithelial cells were measured by stroboscopic microscopy of gill
preparations which had the ipsilateral visceral ganglia attached (VG
preparations) and then tested by superfusion of the visceral ganglia with
dopamine and serotonin. Short term treatments with Mn resulted in a dose
dependant impairment of the dopaminergic, cilio-inhibitory system, which is
in agreement with our previous work. Cotreating animals with Mn and PAS
significantly decreased the neurotoxic effects of Mn. The study shows that
PAS can protect the animal against the neurotoxic effects of Mn and that this
preparation is useful as a model to study Mn neurotoxicity and the
pharmacology of drugs affecting it. This work was supported in part by grants
2R25GM06003-05 of the Bridge Program of NIGMS, 0516041071 of
NYSDOE, and 0622197 of the DUE Program of NSF.
P2.2 HUMFELD, S.C.*; WELCH, A.M.; SMITH, M.J.; GERHARDT, H.C.;
Univ. of Missouri, Columbia, College of Charleston, SC, Arthur Rylah
Institute, Victoria, AU; [email protected]
Phenotypic and genetic variation in season-long calling performance in
gray treefrogs
Sexually-selected traits are often costly to produce or maintain. Because of
these costs, investment in sexual attractiveness may come at the expense of
survival or energetic allocation to other aspects of reproductive effort. These
costs may therefore lead to life-history tradeoffs between current
reproductive effort and residual reproductive value. As a result of such
tradeoffs, snapshot measures of sexually-selected traits may be inadequate
to understand the strength and direction of selection acting on secondary
sexual characteristics. This issue is particularly salient in species with
extended breeding seasons; for example, previous studies of anurans with
extended breeding seasons suggest that the number of nights during which
an individual participates in a breeding chorus is a stronger predictor of
mating success than are values of particular advertisement call
characteristics. In gray treefrogs, males produce an energetically expensive
acoustic advertisement signal, the length of which affects its attractiveness to
females. In order to understand how allocation to various aspects of
reproductive effort influences selection on male mating displays, we are
testing for phenotypic and genetic correlations among call characteristics,
nightly calling effort, chorus participation and season-long calling effort. We
measured these variables over a two-month period from a group of nearly
200 captive male gray treefrogs (Hyla versicolor) resulting from artificial
crosses. Frogs were housed individually in an outdoor array, and each cage
was fitted with a microphone which continually sampled calls over the
two-month period. We will present preliminary results of calling behavior from
these long-term measurements.
P1.106 HUNTER-SMITH, Sarah; HUANG, Liquan; HIEBERT, Sara M*;
Monell Chemical Senses Center, Swarthmore College;
[email protected]
Fatty acid taste receptor expression during cold-induced changes in
dietary lipid preference in Mus musculus
Previous studies have shown that heterotherms such as the Siberian
hamster Phodopus sungorus as well as an obligate homeotherm, the outbred
ICR (CD-1) mouse Mus musculus, increase their preference for a diet rich in
polyunsaturated fatty acids (PUFAs) when they are exposed to a cold
environment. However, the proximate mechanism by which this change in
preference is brought about, and specifically the role of taste receptors in this
process, have not previously been investigated. After two weeks at 22 C,
during which each mouse established its baseline preference for a
PUFA-rich diet relative to a simultaneously offered SFA (saturated fatty
acid)-rich diet, one treatment group was moved to 5 C while the control
group remained at 22 C. Over the following three weeks, the cold treatment
group developed a significantly higher preference for the PUFA-rich diet than
22 C controls. We used quantitative real-time PCR analysis of tongue tissues
obtained after three weeks of cold exposure to examine the expression of
several genes reportedly involved in fat taste (CD36, GPR120, and several
delayed rectifying potassium channels) as well as three genes involved in
sweet, bitter, and umami taste (TrpM5, gustducin, and T1R3) for comparison.
Expression of the putative long-chain unsaturated fatty acid taste receptor
GPR120 was significantly higher in the cold-treatment group, in circumvallate
and foliate papillae as well as in non-taste epithelium. In addition, GPR120
expression was significantly correlated with PUFA-rich diet preference.
These data suggest that GPR120 contributes to the observed cold-induced
changes in lipid preference by increasing PUFA sensitivity through both taste
and trigeminal pathways.
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P3.172 HUSSAIN, F.N.*; MERZ, R.A.; VALLEN, E.A.; Swarthmore College;
[email protected]
How does the cell morphology of the sea anemone, Aiptasia pallida ,
change as a result of its symbiosis with intracellular zooxanthellae?
The ability of hermatypic corals and other anthozoa to host or expel
intracellular symbiotic algae suggests substantial plasticity in cell architecture
depending on the presence of the symbiont. To understand the impact of the
symbiont on host cells involved in a symbiotic relationship, we studied the
changes in cell morphology of sea anemones, Aiptasia pallida , in the
presence or absence of symbiotic zooxanthellae. We hypothesize that
anemones must manipulate their cell shape and cytoskeleton in order to
accommodate zooxanthellae. We co-stained the nuclei and cytoplasmic
f-actin of gastrodermal cells using OliGreen and fluorescently-labeled
phalloidin, respectively. Through confocal microscopy, we observed that the
size of gastrodermal cells increased dramatically as a result of the presence
of intracellular zooxanthellae. Cross-sectional areas of symbiotic host cells
were frequently up to five times greater than the area of aposymbiotic cells.
Furthermore, there were distinct differences in the shapes of cells with and
without zooxanthellae present. Symbiotic gastrodermal cells had rounded
cell membranes that fit snugly over the algal cells, while aposymbiotic cells
were more polygonal in shape. Future research, including staining of
microtubules, may provide insight into how the cytoskeleton in symbiotic
anemones accommodates zooxanthellae. Such knowledge may help explain
the mechanisms by which the symbiosis is initiated, sustained, and
terminated.
P3.84 HUTCHISON, N.L.*; HARRISON, J.S.; ROSTAL, D.C.; Georgia
Southern University, Statesboro; [email protected]
Population and conservation genetics of two Georgia populations of
the gopher tortoise (Gopherus polyphemus)
The gopher tortoise, Gopherus polyphemus, is threatened throughout its
range due in large part to habitat loss and degradation. Gopherus
polyphemus is considered a keystone species in sand hill, longleaf pine, and
scrub ecosystems of the southeastern United States. Two populations in
close geographic proximity (70 miles) were studied whose habitats differ as a
consequence of management practices. Fort Stewart Army Reservation
(FSAR) is frequently burned where as George L. Smith State Park (GLS) is
an infrequently burned habitat. Results of previous research have shown that
FSAR females are significantly larger and produce significantly larger eggs
and hatchlings than GLS females. In addition, surveys at the two sites have
shown that the FSAR site has a larger number of active burrows and a larger
proportion of active to inactive burrows than the GLS site. The main objective
of the study presented here is to characterize the genetic variation within and
between the FSAR and GLS populations of G. polyphemus. Two primary
questions are addressed: 1) Does the level of genetic variation within the
FSAR population differ from that found within the GLS population? 2) What is
the degree of population genetic subdivision between the FSAR and GLS
populations?
P1.92 IGIC, B*; GRIM, T; CASSEY, P; MOSKAT, C; RUTILA, J; HAUBER,
ME; University of Auckland, New Zealand, Palacky University, Czech
Republic, University of Birmingham, UK, Hungarian Academy of Sciences,
Budapest, University of Joensuu, Finland; [email protected]
Perceptual modeling of egg color mimicry in cuckoo-host
coevolutionary arms races
Coevolution between the common cuckoo Cuculus canorus and its passerine
hosts has resulted in a female parasite laying eggs in nests of other birds,
matching the eggshell coloration of the host that she most often parasitizes.
This apparent visual mimicry reduces the chance that hosts recognize and
reject foreign eggs. Past research used the human visual system or
instrumentational measures of light reflectance to assess the extent of
color-mimicry by cuckoo eggshells. Here we used sensory modelling of the
avian visual system to test if color matching by cuckoos is representative of
coevolved perceptual mimicry. We studied eggs from three cuckoo
host-races, from Hungary, the Czech Republic and Finland, together with
Finnish non-host species. We tested the alternative hypotheses that egg
color matching between cuckoos and hosts is due to (i) shared habitat or (ii)
shared eggshell structure, rather than owing to (iii) coevolutionary selection
on mimetic coloration. The avian-perceived match between cuckoo egg
colors was closer between the parasites and respective hosts compared to
non-host species. In contrast, eggshell structure, as measured by shell
thickness, was consistently similar amongst cuckoos compared to hosts and,
thus, independent of cuckoo-host evolutionary interactions. These results
strongly support the (iii) coevolutionary arms-race hypothesis.
P2.122 IHLE, Kate/E*; PAGE, Robert/E Jr.; FONDRK, M/K; AMDAM, Gro/V;
Arizona State University, Arizona State University, Tempe; Norwegian
University of Life Sciences, Aas; [email protected]
Vitellogenin modulates foraging behavior in selected strains of honey
bees (Apis mellifera)
Vitellogenin, a yolk precursor gene, is proposed to have a role in pacing the
foraging onset and in biasing the foraging loads of honey bee workers. In
unselected worker bees vitellogenin knockdown induced through RNA
interference (RNAi) results in early foraging onset and preferential nectar
collection. Two hypotheses, the reproductive ground plan hypothesis
(RGPH) and the double-repressor hypothesis (DRH), provide potential
frameworks for explaining the role of vitellogenin in the regulation of honey
bee worker behavior. While these hypotheses are potentially compatible,
their direct relationship has been untested. We used selected strains of
honey bees with different endocrine sensitivity to vitellogenin, combined with
RNAi to investigate the predictions of and relationship between the RPGH
and DRH. Vitellogenin knockdown differentially affects the selected strains,
demonstrating that the behavioral response to vitellogenin activity is
conditional on the sensitivity of the endocrine repressor system as predicted
by the DRH. We also show that vitellogenin knockdown influences foraging
behavior in accord with the forager RGPH. These results demonstrate the
compatibility of the DRH and RGPH, and show a consistent influence of
vitellogenin activity on worker behavior.
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P3.16 IVANINA, Anna*; KUROCHKIN, Ilya; EILERS, Silke; SOKOLOVA,
Inna; University of North Carolina at Charlotte, University of North Carolina at
Charlotte, Hochschule Bremen, Bremen, Germany; [email protected]
Effect of cadmium and environmental anoxia and re-oxygenation on
metabolism of eastern oysters (Crassostrea virginica).
Heavy metal pollution is a worldwide problem, and cadmium (Cd) is an
important toxicant in estuarine and coastal environments. Alternating
hypoxia/anoxia and re-oxygenation during the tidal cycle is a common stress
in the marine intertidal zone, but physiological consequences of these cycles
and effect of Cd contamination in intertidal organisms are not fully
understood. We have studied the effects of air exposure (1-6 days) and the
subsequent recovery in normoxic water on metabolism of control and
Cd-exposed intertidal bivalves, the eastern oyster (Crassostrea virginica).
Determination of hemolymph oxygen content (PO2) indicates that oysters
become anoxic very rapidly (after 10-20 minutes of air exposure). The hearts
also stopped beating in air-exposure oysters indicating cessation of the
tissue hemolymph supply. During air exposure control and Cd-exposed
oysters accumulated anaerobic end products (succinate, acetate and
L-alanine) in tissues, but the concentrations of anaerobic metabolites were
significantly higher in control oysters compared to the Cd-exposed ones
indicating lower anaerobic capacity in Cd-exposed oysters. There was a
significant decrease in ATP levels and ATP/ADP ratio during the air
exposure. Concentration of tissue metabolites (including anaerobic end
products and adenylates) returned to the control levels after 12h of
re-oxygenation in control but not in Cd-exposed oysters. These findings
show that in presence of Cd the metabolic response of oysters to anoxia and
subsequent recovery of upon reoxygenation are inhibited. Supported by NSF
CAREER (IBN-0347238).
P3.174 IYENGAR, EV*; PETCHLER, E; HUTCHINSON, KA; Muhlenberg
College; [email protected]
He is heavy & he aint my brother: Marine snails catching a ride
Symbiotic interactions beg the question as to the degree to which the guest
has specialized on a particular host and the relative costs and benefits of the
association to each participant. On San Juan Island, Washington, the
suspension-feeding marine snail Crepidula adunca is found almost solely
residing in a characteristic, external location on the body whorl of the snail
host Calliostoma ligatum. Numerous other hosts are available, including
Margarites pupillus, a sympatric snail in the same taxonomic family as
Calliostoma with a similar shell shape. Field transects indicated that
individuals of Crepidula in the San Juans reside on Calliostoma more than on
any other host. The incidence of infection across sites ranged to >80%, with
an average epibiont load of up to >3 individuals per host, representing an
addition of >7% of the body weight of the host. In laboratory choice
experiments, individuals of Crepidula preferred Calliostoma hosts to the
other common potential hosts, including hermit crabs in Calliostoma shells.
Crepidula did not show a preference for intact versus sanded Calliostoma
shells. These results suggest that the cue used by Crepidula to identify an
appropriate host is likely from live Calliostoma tissue or is in Calliostomas
shell and rapidly degrades post-mortem. In general, predators (two species
of sea stars, two species of crabs, one snail) did not eat many Calliostoma,
whether they were infected with Crepidula or not. Thus, Crepidulas presence
does not confer a protective benefit to Calliostoma against the common
predators. This symbiotic interaction is likely parasitic, as the additional
weight and surface area from Crepidula epibionts likely result in energetic
costs for the Calliostoma host and no benefit for the host has been identified.
P3.81 JANANANDA, B.G.*; WIKRAMANAYAKE, A.; BUTLER, M.; University
of Miami, University of Hawaii at Manoa; [email protected]
Molecular Evolution of Damselfly Opsin Genes
In the Hawaiian archipelago, Megalagrion damselflies have radiated,
entering new breeding habitats independently at least six times and have
evolved bright body coloration numerous times. We are investigating whether
they have undergone visual system adaptations to shifts in the light
environment. The visual pigments or the opsins are a group of light-sensitive,
membrane-bound G protein-coupled receptors found in photoreceptor cells
of the retina of the eye. Variation in amino acid sequences of the visual
pigments is one potential source of variation in visual sensitivity among
photoreceptors. We will examine amino acid changes and whether they are
correlated with or precede habitat shifts. We cloned and sequenced the
cDNAs of ultraviolet (UV) absorbing rhodopsin of five different Megalagrion
species using RT-PCR. The UV sequences, each encoding 387 amino acids
are 72-73% identical to the UV absorbing rhodopsin of Apis mellifera. Even
among these very closely related species, we find several synonymous and
nonsynonymous substitutions. We will test for adaptive evolution in different
domains of the opsin protein, and whether evolutionary changes are
correlated with shifts in light habitat and body coloration.
P3.196 JANKOWSKI, Mark D*; FRANSON, J Christian; HOFMEISTER, Erik;
Los Alamos National Laboratory; [email protected]
How might changes in corticosterone levels in breeding greater-sage
grouse affect immunity?
Greater sage-grouse (GRSG, Centrocercus urophasianus) populations are
thought to have decreased by up to 93% since pre-settlement times. Male
GRSG participate in spring mating rituals that involve intraspecific
competition and reduced feeding. We investigated whether cattle grazing
could be a stressor by studying GRSG fecal corticosterone (CORT)
concentrations in exposed and unexposed populations. We found that
lekking females but not males had elevated levels of CORT when resident in
actively grazed sites. Males uniformly showed higher CORT levels during
lekking compared to the brood-rearing period. Next, we investigated if
elevated CORT might be uniformly immunosuppressive. Therefore, we
performed a laboratory study using the domestic chicken (Gallus
domesticus) to determine whether subacute elevations of CORT cause
immunosuppression to both non-replicating and replicating antigens.
Compared to controls, birds exposed to 10 days of CORT in their drinking
water produced lower antibody levels to sheep red blood cells but more
antibodies to West Nile virus (WNv). We suspect that CORT suppressed the
same immune factors to both antigens, but that suppressed innate immunity
allowed WNv to quickly replicate, leading to a higher viremia and a greater
stimulus for antibody production. The relationship between higher CORT
levels and immunosuppression in birds behaving according to their life
history stage and those experimentally manipulated for higher levels of
CORT should be addressed. These findings may stimulate further work to
investigate how life history stage affects the neuro-endocrine-immune triad in
the context of environmental change and perhaps as this relates to wildlife
and public health risk.
e249
P3.145 JENSEN, BH*; CASEY, A; The College of Saint Rose;
[email protected]
Mummichog (Fundulus heteroclitus) from Cape Cod have a lower
frequency of spontaneous ovarian contractions than has been reported
from a Delaware population.
It is well established that the ovaries of teleost fish spontaneously contract.
However, the purpose of these contractions is not well understood largely
because there is so much variability in the frequency, amplitude, and timing
of the spontaneous ovarian contractions between different species of fish.
Our lab has been working with Danio rerio (zebrafish) and Fundulus
heteroclitus (mummichog) to try and elucidate the purpose of these
contractions. We have previously reported the presence of spontaneous
contractions in the zebrafish and lack of regular spontaneous contraction in a
northern population of mummichog. Both of these findings led us to the
conclusion that there is indeed some reproductive role for spontaneous
ovarian contractions in fish. We are currently presenting data that indicate
that the Cape Cod population of mummichog that we are working with has a
much lower frequency of spontaneously occurring ovarian contractions in
sexually mature fish than has been reported in their southern counterparts
(southern Delaware). Both the northern and southern populations are
strongly responsive to Acetylcholine, indicating they are both capable of
contacting. The fact that the northern population generally lack spontaneous
contractions indicates that function of these contractions may have little
importance in the mummichog further confusing our understanding of the
role of spontaneous ovarian contractions in fish. Additionally, the current
study points to physiological difference in the reproduction of the northern
and southern populations of mummichog in the past behavioral differences
were primarily noted.
P2.36 JIMENEZ, A.G.*; KINSEY, S.T.; DILLAMAN, R.; KAPRAUN, D.F.;
University of North Carolina Wilmington; [email protected]
Nuclear DNA content variation in decapod crustaceans: Does
hypertrophic growth affect genome size in muscle fibers?
Decapod crustacean anaerobic muscle fibers grow hypertrophically, leading
to extremely large fiber sizes in adults, while juvenile animals have muscle
cells that fall in the normal cell size range. We were interested in examining
the nuclear genome variation in cells that increase in size throughout
ontogeny. A DNA-localizing fluorochrome DAPI (4,
6-diamidino-2-phenylindole) and RBC (chicken erythrocytes) standard was
used with image analysis and static microspectrophotometry to estimate
nuclear DNA contents in four decapod species including a portunid crab
species, Callinectes sapidus, a grass shrimp species, Palaeomonetes pugio,
a penaid shrimp species, Penaeus aztecus, and a lobster species, Panulirus
argus at juvenile and adult life stages. C-values (2C nuclear DNA contents)
derived from diploid (4C) hemocytes, range from 1.05 - 4.35 pg. Nuclear
DNA content increase was correlated with muscular hypertrophy, and
intracellular variation (endopolyploidy) of DNA contents of 8 -32 C was
demonstrated. Correlations between genome size and phylogeny are
discussed in four different species of phylogenetically distant and
morphologically and developmentally different decapod crustaceans.
P2.150 JIMENEZ, Stephanie*; FAULKES, Zen; The University of Texas-Pan
American; [email protected]
Establishment of a research colony of Marmorkrebs, a parthenogenetic
crayfish species
Marmorkrebs, or marbled crayfish, are recently discovered parthenogenetic
crayfish. Its origins are unknown, but it has been introduced into natural
ecosystems and could become a highly invasive pest species. Marmorkrebs
have potential as a model organism for research in many biological fields
because they are genetically uniform. A key element of most successful
model organisms is maintaining self-sustaining breeding colonies. We report
on our efforts find the best conditions for establishing and maintaining a
Marmorkrebs breeding colony for research. The colony was founded by four
adults of unknown age (P generation). These foundresses were housed
communally in standard aquaria and mainly fed vegetables (mostly peas),
which were readily eaten. All adults generated multiple large batches of
embryos, although three adults died over the course of a year. One daughter
of the original adults (F1 generation) had her own offspring (F2 generation).
The colony contained 14 descendants of the original adults after one year.
The colony was later supplemented with additional 72 juveniles, which
experienced 7% mortality in the first month in the colony. High juvenile
mortality poses the most significant obstacle to establishing a research
colony of Marmorkrebs, although relatively few adults would be needed to
supply many viable embryos for developmental research.
P3.45 JOHNSON, J. I.*; MORRIS, J. A.; FOBBS, A. J.; Mchigan State Univ.,
Michigan State Univ., National Museum of Health and Medicine, Armed
Forces Institute of Pathology; [email protected]
A Map of Sensory Projections to the Insular Cerebral Cortex.
To construct a map of sensory projection regions in cerebral cortex of the
insula, we reviewed data from studies of human, monkey, rodent and cat
brains. This map shows a distribution of sensory inputs in concordance with
our hypothesis of the insula as a hub of sensory cortical areas. The
antero-inferior extremity of the insula lies next to, and has multiple
interconnections with, primary olfactory cortex; it is agranular cortex: a virtual
absence of inner granular layer IV. Posterior to, and well connected with, this
olfactory region, is the wide expanse of the Primary Taste Cortex,
characterized by dysgranular cortex: an intermittent layer IV. Around the
Taste Region are sensory inputs from Visceral Afferents, including those
involved in cardiopulmonary, digestive, and urinary bladder regulation. In the
posteriormost insula is granulous cortex: a well-developed and continuous
layer IV. Most superiorly within this posterior granulous region, close to
primary and secondary somatosensory cortex, are somatotopically organized
Thermosensory and Mechanosensory projections. Posterior and inferior to
these, at the posterior insular extremity, are mixed Vestibular and Visual
projections. Auditory projections lie more inferior, close to Auditory regions in
the superior temporal gyrus. There are extensive interconnections between
the respective sensory regions, and between these regions and executive
output regions of the superior anterior agranular insular cortex.
e250
P3.15 JOHNSON, S.R.; MAUTZ, W.J.; DOHM, M.R.*; Chaminade University,
Honolulu, HI, University of Hawaii at Hilo, Hilo, HI; [email protected]
Effects Of Ozone Exposure On The Specific Dynamic Action Of The
Cane Toad, Bufo marinus
Ozone (O3), a highly reactive gas, is a common air pollutant in many urban
settings and in adjacent wildlife habitats. Acute O3 inhalation causes airway
inflammation and decreased lung function, with effects more pronounced in
exercise and other factors that elevate metabolic rate. In previous studies
with amphibians and reptiles exposed to O3, we noted decreased breathing
rates and reduced oxygen consumption at rest. We tested whether an acute
O3 exposure (4 h) would affect specific dynamic action (SDA), the increase in
metabolism associated with food processing in animals. Metabolic rates for
15 toads (mean + SD body mass at start of experiment: 108 + 31.0 g) were
estimated from rates of carbon dioxide (CO2) production and oxygen (O2)
consumption at 30 C by open-flow respirometry (flow rate = 100 SCCM) over
seven days. After an initial 24 h period to estimate standard resting metabolic
rates (SMR, mean + SD: 4.7 + 2.86 ml CO2/h), toads were force fed canned
dog food (crude protein 8%, fat 3%, water 78%) approximately 10% of body
weight and returned to the metabolic chamber for the next 24 h of metabolic
recordings. On the third day, toads were randomly assigned to control (air) or
O3 (0.8 parts per million, flow rate = 5 liters per min) for 4 h at 30 C, then
returned again to metabolic chambers for an additional 5 days of metabolic
recordings. Peak CO2 rates increased by a factor of 4.6 in the next 24 h and
6.1 over SMR by 48 h. Individual differences in CO 2 production were
significantly repeatable (P < 0.001), however, we found no significant
differences between air and ozone-exposed toads in SDA (P = 0.129,
split-plot rank ANCOVA). Therefore, acute exposure to O3 had little or no
effect on the obligate postprandial increase in metabolism.
P2.31 JOHNSON, S.E.*; TOMANEK, L.; California Polytechnic State
University; [email protected]
Linking organic pollutants to tumor growth in arrow goby, Clevelandia
ios, in Morro Bay: Proteomics as a tool for biomarker discovery
Morro Bay is a marine sanctuary on the central coast of California. It is
considered a pristine ecosystem; showing little contamination from urban or
agricultural inputs. However, our preliminary studies have shown a high
incidence of primordial gonadal and liver tumors in arrow goby, Clevlandia
ios, collected from the mudflats in Morro Bay. This is indicative of persistent
organic pollutants: chemicals that are found in extremely low levels in water
and are not easily detected by traditional water quality methods; however,
they do harmfully accumulate in organisms. Through chemical analysis we
found high levels of 4-nonylphenol in arrow goby tissues, as well as in
sediment and water from the bay. Nonylphenol is a persistent end product of
the biodegradation of alkylphenol ethoxylates, a group of chemicals that are
used as surfactants in household and commercial products. Previous data on
persistent organic pollutants in Morro Bay is been limited because detection
by existing water testing regimes is deficient, though the biological effect is
present. Therefore, new sensitive tools for measuring the biological response
to wetland contaminants are urgently needed before detrimental effects such
as tumors or reproductive impairments occur. We are developing a tool via
proteomics to identify biomarkers of chemical contamination. Through in-lab
exposure to nonylphenol, and two-dimensional gel electrophoresis we can
track the simultaneous changes in expression of hundreds to thousands of
arrow goby liver proteins. We will identify proteins of interest with mass
spectrometry; and though the arrow goby is not a model organism, we have
already successfully identified several proteins using MALDI-TOF-TOF mass
spectrometry. Once developed, such biomarkers can then be used to as an
early detection to announce the presence of emerging pollutants.
P1.160 JOHNSTON, Gwynne I.H.*; SHAFFERY, Heather M.; MOORE,
Michael C.; Arizona State University; [email protected]
Does Maternal Stress Alter Egg Composition?
Many studies have shown that treating females with hormones can alter the
phenotype of their offspring. These phenotypic effects could be due solely to
changes in hormone levels in the eggs. Or, hormonal treatment of females
could cause them to alter the composition of their eggs, which could then
affect offspring phenotype. These hypotheses are not mutually exclusive, but
to date most studies have overlooked the possibility of egg compositional
changes. In a previous study, we treated female tree lizards (Urosaurus
ornatus) with a pharmacological dose of corticosterone, the primary hormone
involved in the stress response, and found that eggs from treated females
had less egg mass but were not different in size. In this study, we treated
females with a physiological level of corticosterone to determine if it affected
egg composition. We found no significant differences in any of the egg
compositional aspects measured - average egg mass or size, water content,
or amount of lipids, proteins, or salts. These results suggest that offspring
phenotypic effects due to maternal treatment with corticosteroids are
primarily caused by hormonal changes in the eggs and not changes in egg
composition.
P1.103 JONES, AJ*; MURRAY, JA; CAIN, SD; WYETH, RC; U. Montana,
Cal. State. U. East Bay, E. Oregon U., St. Francis Xavier U.;
[email protected]
The influence of odor cues, water flow, & magnetic fields on the
orientation of the sea slug Tritonia diomedea
Tritonia diomedea is suitable for studying the integration of multiple sensory
cues and their role in navigation because it has as a well-characterized
central nervous system with re-identifiable neurons & consistent orientation
behaviors. Several sensory stimuli that have been previously shown to
influence orientation behavior (rheotactic, olfactory, magnetic) were
manipulated in order to test the role each plays in influencing the slugs
navigation towards food. We elicited foraging behavior in starved T.
diomedea placed in a flow tank downstream from prey (Ptilosarcus gurneyi).
We hypothesized that after orienting to a food odour plume and then
removing the source of the odor, Tritonia would use geomagnetic cues to
maintain a bearing towards the original odor source location in the absence
of either olfactory and/or rheotactic cues ('orienteering' hypothesis). As found
previously, odors played a gating/motivational role in foraging behavior, and
rheotactic stimuli helped orient the animal upstream toward the odor source.
Geomagnetic field reversals had no apparent effect on slug movements
compared to controls, with or without flow and with or without odors. Thus we
found no evidence in support of the orienteering hypothesis. We also
observed a novel mode of navigation, cross-current 'casting' or
'counterturning' (successive left and right turns), following odor removal.
Before removal of the odor & flow, turning radius and angular speed were
relatively smaller. After odor removal, with or without water flow, the turns
were more frequent, with a shorter turning radius, and a lower angular
speed.
e251
P2.186 JOST, JA*; O'ROURKE, M; FUREY, N; DIONNE, M; FREDERICH,
M; University of New England; [email protected]
A novel cellular marker for temperature stress in marine invertebrates
In the context of global climate change the need to assess the effects of heat
stress in marine organisms is increasing. Heat shock proteins (HSP) are
frequently used as an indicator for heat stress, but there is often a time lag of
several hours between the actual heat stress and detectable up-regulation of
HSPs. For identifying an earlier stress indicator, we investigated whether
AMP-activated protein kinase (AMPK), a regulator of cellular energy, is
activated by temperature in the rock crab, Cancer irroratus. Crabs were
exposed to a fast temperature increase (6°C/hour) and heart tissue was
sampled every 2°C between 12 and 30°C. Righting reaction times, AMPK
activity, total AMPK protein and mRNA, HSP70 protein and mRNA, and
lactate accumulation were measured. There was no detectable change in
righting response up to 18°C. Above 18°C, reaction time slowed, and AMPK
activity increased. At 28°C, there was a loss of righting response, an onset
of anaerobiosis, indicated by lactate accumulation, a peak in AMPK activity,
and a slight increase in HSP70 mRNA expression. The combination of
reduced motor activity, biochemical and molecular markers can be used to
characterize temperature thresholds in the context of Shelfords law of
tolerance. We propose that the onset of AMPK activity and reduced motor
activity at 18°C, coinciding with the average maximum temperature where
the animals were collected, indicates the transition from the optimum range,
into a range between optimum and pessimum, defined as the pejus range.
Therefore, AMPK activity is a cellular marker that can detect temperature
stress in a marine invertebrate earlier than HSP70, and may serve as a tool
for detecting temperature stress in other invertebrate species as well.
P1.161 KAISER, A.*; LACAZE, M.; WALKER, A.; Midwestern University,
Glendale, AZ; [email protected]
Effects of hyperoxia and intubation of spiracles on oxidative stress in
pupae of the moth Antheraea polyphemus.
It has been hypothesized that the air-filled tracheal system of insects has
such a high capacity for gas exchange that oxygen supply at rest has to be
shut down to prevent excessive oxidative stress. Therefore, insects possess
spiracular valves, which control gas exchange between atmosphere and
tracheal system. When the spiracles are closed, insects consume oxygen
from the tracheal space, reducing intratracheal oxygen partial pressure (PO2)
and perhaps oxidative stress. In this study, we tried to assess the
antioxidative function of spiracular control in moth pupae. In one group of
animals, we intubated the first three pairs of abdominal spiracles, forcing
them to remain constantly open. For 24 hours, we exposed untreated and
intubated pupae to either 21% O2 (normoxia) or 40% O2 (hyperoxia). We
measured CO 2 release rate to control for changes in metabolism and
spiracular function. Pupae revealed cyclic, but not discontinuous CO 2
release. After exposure we separated the pupae in three sections: front
(head, pro- and meso-thorax), center (meta-thorax and part of abdomen with
intubated spiracles), and rear (mobile part of abdomen with untreated
spiracles). We measured H 2 O 2 production (radical production), total
antioxidant capacity, and protein carbonyl concentration (oxidative damage)
in the three parts. Neither intubation nor exposure to hyperoxia had a
significant effect on any of the parameters between treatment groups. There
was, however, a significantly smaller concentration of H2O2 and antioxidant
capacity in the frontal section compared to the other sections. We suggest
that there are either morphological or biochemical differences between
frontal section and the rest of the body. We also suggest that 24h blocking of
spiracular closure is either not a significant oxidative stressor for with cyclic
rather than discontinuous CO2 release or that oxygen supply is reduced by
other mechanisms, like water-filled tracheoles.
P2.105 KAJI, Tomonari; Shizuoka Univ., JAPAN ;
[email protected]
Functional change of appendage in ostracode ontogeny
Exoskeleton of arthropodes is re-created at every molting period.
Accordingly, the external morphology metamorphoses intermittently through
molting. On the other hand, in some crustaceans generally, function of
appendage metamorphoses intermittently through ontogeny. Therefore,
intermittent change of function requires that of correlation because function
of appendage depends on the integrated correlation between exoskeleton
and muscles in each appendage. Cypridocopain ostracodes change one of
appendages functionally from a walking leg to a maxilliped through the
molting growth. In this study, the 3-D structures of exoskeletal-muscular
systems were observed by the confocal laser-scanning microscope in some
species of Cypridocopina. As a result, it is shown that the musclar system
(arrangement of muscles) is not changed by the functional change of
appendage. I can conclude that the intermittent change of correlation in the
crustacean appendage is assured by the exoskeletal metamorphosis rather
than the change of musclar system.
P1.53 KANE, E. A.*; MARSHALL, C. D.; Department of Wildlife and
Fisheries Science, Texas A and M University, Department of Marine Biology,
Texas A and M University at Galveston; [email protected]
Suction and ram feeding kinematics in two divergent odontocetes
The feeding behavior and morphology of some species of odontocetes are
convergent with other aquatic suction feeders; however, few cetacean
kinematic feeding studies have been conducted. To explore suction and ram
feeding in odontocetes, controlled feeding trials using 7 beluga whales
(Delphinapterus leucas) and 7 Pacific white-sided dolphins (PWD;
Lagenorhynchus obliquidens) were conducted. Kinematic analysis used
anatomical landmarks to characterize feeding behavior. Mean kinematic
variables for belugas were: max gape = 7.18 cm +/- 2.78, time to max gape =
250 ms +/- 170, max gape angle = 16.9 +/- 4.89, max gape angle opening
velocity = 118/s +/- 50.0, max gape angle closing velocity = 120/s +/- 48.7,
max hyoid depression = 2.80 cm +/- 1.87, time to max hyoid depression =
397 ms +/- 339, max prey velocity = 227 cm/s +/- 98.9, and gape cycle
duration = 526 ms +/- 310. Lateral gape occlusion was observed for belugas
in all trials; max percent of rostrum length occluded at initial prey movement
= 82.0% +/- 8.35; height-to-width ratio of the pursed aperture in belugas was
nearly circular. Beluga pursed gape variables were: max pursed gape angle
= 76.4 +/- 20.7, max pursed gape angle opening velocity = 872/s +/- 427,
max pursed gape angle closing velocity = 1092/s +/- 509. All PWD
kinematics were significantly different than belugas except max gape, max
gape angle, and hyoid depression. Some pursing in PWD was observed in
most trials; max percent length occluded = 40.5% +/- 25.6 and pursed
aperture ratio was non-circular. Ram-suction index was -0.03 +/- 0.37 for
belugas and +0.32 +/- 0.40 for PWD. Belugas appear highly specialized for
the generation of suction despite RSI values. Ram feeding was dominant in
PWD, but some suction ability was observed.
e252
P1.145 KAPPER, M.A.*; DEPAOLO, C.; Central Connecticut State Univ.,
New Britain; [email protected]
IMMUNOFLUORESCENCE LOCALIZATION OF AQUAPORIN DURING
SALINITY ADAPTATION
During adaptation to changes in salinity osmoconforming intertidal and
estuarine molluscs utilize a comprehensive suite of strategies to maintain
osmotic homeostasis. Behavioral methods temporarily delay contact
between cells and altered environmental salinities while physiological
mechanisms modulate the concentration of intracellular free amino acids to
equilibrate the concentration of intracellular and extracellular osmolytes. We
are hypothesizing that during the process of physiological salinity adaptation
in the ribbed mussel Geukensia demissa, the water permeability of cell
membranes is modulated by trafficking aquaporin water channel proteins
from the cell membrane to intracellular vesicles, effectively reducing potential
water flux between the extracellular and intracellular compartments, allowing
more time for adjustment of the intracellular solute concentration. We are
developing immunofluorescence microscopy procedures to visualize the
subcellular location of aquaporin-2 in mussel gills. Gills from mussels
maintained at 15oC and 15o/ooS were excised and incubated at 15oC and
30 o /ooS with aeration. Samples were fixed, embedded in paraffin and
sectioned (5 microns) at 0, 30, 60, 120 and 180 minutes following salinity
transfer. One set of slides was stained with hematoxylin and eosin for
brightfield microscopy while a second set was exposed to an anti aquaporin
2 antibody followed by a secondary antibody conjugated to the fluorescent
dye Alexa Fluor 568 and examined by fluorescence microscopy at 1000X
magnification. Immunofluorescence preparations omitting the primary anti
AQP antibody were used as controls, allowing tentative intracellular
localization of the aquaporin protein. Supported by CSU AAUP and Student
Faculty Research Grants to MAK.
P2.111 KAWANO, S.M.*; SCHOENFUSS, H.L.; MAIE, T.; BRIDGES, W.C.;
BLOB, R.W.; Clemson University, St. Cloud State University;
[email protected]
Comparative Morphological Selection: Waterfall-climbing in Gobiid
Fishes from Dominica versus Hawai'i
When closely related species are exposed to similar selection pressures, will
they respond in similar ways? To investigate this question, we subjected
juveniles of the amphidromous gobiid fish Sicydium punctatum from the
Caribbean island of Dominica to climbing trials up an artificial waterfall (~100
body lengths) to evaluate body shape differences between successful and
unsuccessful climbers, and then compared our results to those of previous
studies on the closely related species Sicyopterus stimpsoni from Hawaii
(Big Island). Failure rates were greater in fish from Dominica (>50%) than in
fish from Hawaii (~30%). However, selection did not yield the same patterns
between the two species. Although numerous morphological differences
were found to be significant between successful and unsuccessful climbers
in S. stimpsoni from Hawaii, calculations of selection differentials and
gradients showed very few significant patterns of directional selection on
morphology induced by climbing in S. punctatum from Dominica. The
differing responses of Hawaiian and Dominican gobiids may be related to
differences in the selective pressures that have acted on these species
through their evolutionary history. For example, while the waterfalls scaled by
Dominican gobiids are typically less severe than those scaled by gobiids on
the Big Island, Dominican gobiids are exposed to in-stream predators that
are absent above waterfalls on Hawaii. Our findings suggest that selection
need not operate in a uniform manner amongst closely related groups, and
that several factors might act to counter expected effects of natural selection
on specific aspects of performance. Supported by NSF (IOS-0817794,
IOS-0817911).
P3.207 KAWARASAKI, Y.*; YI, S.-X.; LEE, ; Miami University, Oxford, Ohio,
Miami University, Oxford, Ohio; [email protected]
Rapid Cold-Hardening Protects Against Cold-Induced Apoptosis: Role
of Bcl-2 Protein
Rapid cold-hardening (RCH) describes an extremely swift acclimation
response to low temperature stress. A brief acclimation to a moderately low
temperature dramatically increases insect survival to a subsequent cold
exposure that would be lethal otherwise. Recently, it was reported that
chilling injury induces apoptotic cell death, while the RCH response
significantly reduces the number of apoptotic cells. The possible involvement
of anti-apoptotic Bcl-2 protein family was proposed since RCH preserved its
expression level of these proteins, while it was reduced by cold shock. We
investigated the protective role of the Bcl-2 protein, Buffy, against
cold-induced apoptosis during RCH, using a mutant strain of Drosophila
melanogaster that lacks expression of this Bcl-2 protein. This mutant strain
showed significantly lower survival (5.4 +/- 2.1%) after a cold shock
treatment of -5.5°C for 2 h, compared to wild type flies (65.7 +/- 4.8%). In
addition, the RCH response in the Buffy mutant strain was compromised; in
wild type flies, RCH (5°C for 2 h) significantly increased survival after cold
shock (-6°C for 2 h) from 4.0 +/- 2.8 to 81.6 +/- 5.5%, whereas survival rates
only increased from 0 to 16.0 +/- 5.2% in the Buffy mutant strain. The TUNEL
assay was used to determine whether the reduced capacity for RCH was
associated with increased apoptosis in the Buffy mutant strain. In addition,
Western-blotting was used to investigate how cold shock and RCH treatment
affects the protein expression of this Bcl-2. Our initial results suggest that the
anti-apoptotic Bcl-2 protein plays a role during RCH for protection against
cold-induced apoptosis. Supported by NSF grant IOB-0416720.
P1.15 KELLY, CD*; JENNIONS, MD; Iowa State University, Australian
National University; [email protected]
Sexually dimorphic immune response in the harem polygynous
Wellington tree weta, Hemideina crassidens
Adult males are often less immunocompetent than females. One explanation
for this is that intense sexual selection causes males to trade-off investment
in immunity with traits that increase mating success. We tested this
hypothesis in the Wellington tree weta (Hemideina crassidens), a large,
sexually dimorphic orthopteran insect in which males possess enormous
mandibular weaponry that are used to fight for access to female mates.
Field-collected males had a significantly greater immune response (greater
melanotic encapsulation) than females, suggesting that body condition,
longevity or an allied trait is important to male fitness or that females require
materials for egg production that would otherwise be used to boost immunity.
Although immunity is expected to trade-off against reproductive traits in both
sexes, there was no significant relationship between immune response and
weapon or testes size in males nor fecundity in females.
e253
P2.52 KEMP, AD*; THORINGTON, RW; Mount Holyoke College, National
Museum of Natural History; [email protected]
Osteology as a predictor of ecology in the Marmotini
The 273 species of the Sciuridae are exceptionally diverse in terms of the
habitats they utilize and range from entirely terrestrial to strictly arboreal.
These differences are reflected in their hand morphology- in arboreal
squirrels the fourth digit is longest, while terrestrial squirrels possess a longer
third digit. To test the hypothesis that hand morphology shows similar trends
in a smaller, less ecologically diverse clade, we examined various
proportions of hand bones within the largely terrestrial tribe Marmotini. We
took digital x-rays of over 1,500 specimens representing roughly 50 species
and digitized the lengths of all metacarpals and phalangeal bones. The ratio
of the length of digit four to digit three varies in a way that is loosely tied to
ecology at the intergeneric level. For example, the most terrestrial genus,
Cynomys, possesses the smallest fourth to third ratio (0.86 +/- 0.02; N=84)
while the semi-arboreal Tamias genus possesses the highest (0.97+/- 0.03;
N=183). However, hand proportions are not a consistently accurate predictor
of ecology at the species level. The morphological data also fit well with the
current taxonomic breakdown- the genera and super-generic groups are
generally morphologically homogenous and distinct from the rest of the
sampling. The recent breakdown of Spermophilus, sensu lato, into eight
genera is supported by our findings in that the new genera are more
morphologically homogenous than the previous grouping. Fluctuating
asymmetry between the bones of the right and left hands was also
investigated and found to be within the normal biological range. In summary,
while hand proportions can be used to predict ecology as low as the generic
level, the lower the taxonomic level the less consistent the trends and the
less reliable the predictions.
P3.133 KENISON, Erin K.*; SAPORITO, Ralph A.; Skidmore College, Old
Dominion University; [email protected]
Further studies of predation and aposematism in the dendrobatid
frog,Oophaga pumilio, from northeastern Costa Rica
Organisms use a variety of strategies to defend themselves against
predators. Some organisms advertise their defenses to predators with bright
colors and/or patterns, a phenomenon known as aposematism. In many
cases, predators learn to associate coloration with unprofitability and avoid
aposematic organisms, however in some cases avoidance is innate. Brightly
colored poison frogs contain an alkaloid-based chemical defense, and it has
been recently demonstrated that coloration in the dendrobatid frog, Oophaga
pumilio, functions as an aposematic signal to natural predators. Although
chemically defended and brightly colored, O. pumilio remains subject to
occasional predation. Herein we report the results of two field-based
experiments designed to gain a better understanding of aposematism and
predation on O. pumilio from Costa Rica. We used plasticine frog models to
experimentally evaluate natural predation rates on O. pumilio. In our first
experiment, we assessed predation among 4 different habitat types, which
differed in forest characteristics and bird abundances. Birds were found to be
the most common predator. However, there was no difference in predation
among the 4 habitats, suggesting that predation on O. pumilio does not differ
with forest structure or predator density. In our second experiment, we
examined the importance of color and shape, with regard to the aposematic
signal of O. pumilio, by examining predation rates between red and
brown-colored, frog and ball-shaped plasticine models. Our results
demonstrate that bird predators can distinguish between different colored
and shaped models, and suggest that both color and shape are important in
the aposematic signal of O. pumilio.
P3.150 KHAMBATY, M.; ECAY, T.W.*; STEWART, J.R.; East TN State Univ;
[email protected]
Carbonic Anhydrase II Expression in the Chorioallantois of the Corn
Snake, Pantherophis guttatus
The shell of oviparous reptile eggs provides a substantial amount of calcium
to the developing embryo. In corn snakes, the eggshell provides 28% of the
calcium in hatchlings with the remainder coming from yolk. The
chorioallantois contributes to calcium homeostasis during embryogenesis by
mediating the transport of shell calcium to the embryo. Shell calcium is in the
form of crystallized calcium carbonate deposited primarily on the outer
surface. Our objective is to understand how the embryo regulates dissolution
of mineralized shell calcium and its transport to the embryo during
development. We hypothesize that cells of the chorioallantois secrete acid
onto the eggshell thereby dissolving calcium carbonate crystals. Acid
production is catalyzed by carbonic anhydrase II. Immunoblotting
demonstrates an increase in carbonic anhydrase II expression throughout
development in the chorioallantois but no detectable expression in the yolk
sack. Increased carbonic anhydrase II expression in the chorioallantois is
coincident with increased calbindin-D28K expression, a marker for calcium
transport. Histochemical staining identifies carbonic anhydrase positive cells
at the outer surface of the chorioallantois adjacent to the eggshell. Carbonic
anhydrase II and calbindin-D28K immunohistochemisty are being used to
determine if acid secretion and calcium transport occurs in the same or
different cells. Supported by the NSF (IOB-0615695) and an APS
Undergraduate Summer Research Fellowship.
P3.191 KIDD, M.R.*; HOFMANN, H.A.; Univ. of Texas at Austin;
[email protected]
Hormonal Regulation of Female Sexual Behavior in a Cichlid Fish
Female sexuality is regulated by levels of circulating hormones mediated by
the preoptic-hypothalamic axis. While many studies have looked at the
neurobiology, physiology or behavioral ecology associated with female
sexual behavior, these different processes have yet to be integrated into a
single model system. Using the cichlid fish Astatotilapia burtoni , we
examined the endogenous factors that regulate female sexuality on a fine
temporal scale by relating circulating hormones levels to changes in oocyte
maturation and female affiliative and choice behavior. Even though females
overwhelmingly chose to spawn with large males (N=95, p<0.001), their
association behavior does not reflect their eventual choice until the day of
spawning. In addition to the observed change in association preference, the
amount of time spent in a mating bower (p<0.001) and the number of
receptive circles performed (p<0.001) by a female increase sharply on the
day of spawning. Temporal patterns of circulating hormones 17beta-estradiol
(E2), testosterone (T), progesterone (P), and prostaglandin F2 alpha (PGF2)
are consistent with those of other vertebrates, yet the occurrence of
consecutive hormone peaks within only the last week prior to spawning was
surprising. Additionally, while both E2 and T are thought to decrease as
levels of circulating P increase, our results suggest that P and T peak at the
same time (-4 days pre-spawning). The surge in testosterone precisely
coincides with a dramatic increase in female aggression towards unattractive
males. Finally, none of the canonical hormones associated with female
sexual behavior (E2, T, P, PGF2) are elevated at the time of spawning
(rather, they are in a state of marked decline). These results provide novel
proximate insights into mate choice behavior.
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P3.192 KIDD, C.E.; KIDD, M.R.; HOFMANN, H.A.*; Univ. of Texas at Austin;
[email protected]
A technique for measuring multiple hormones from individual water
samples using commercial enzyme immunoassays
Understanding the relationship between hormones and behavior requires the
concurrent examination of multiple hormones. However, repeated blood
sampling can impact the very behavior under study and compromise the
subjects overall condition, particularly in small animals. Also, hormones
released into the water by teleost fishes can play a role in schooling,
migration, alarm reactions, behavioral and physiological responses during
reproduction, and parent-offspring interactions. Consequently, the
non-invasive analysis of hormone levels in fish holding water using either
radioimmunoassay or enzyme immunoassay (EIA) is becoming increasingly
common, yet few studies measure more than one hormone at a time.
Commercial EIAs for different hormones often rely on different assay buffers,
which can make measuring multiple hormones from the same water sample
difficult, if not impossible. Using the African cichlid fish Astatotilapia burtoni ,
a major model system for the analysis of the molecular, endocrine and neural
mechanisms underlying socially regulated plasticity in brain and behavior, we
first introduce a procedure that allows the measurement of 17beta-estradiol
(E2), testosterone (T), progesterone (P), and prostaglandin F2 alpha (PGF)
from a single concentrated water sample using commercial EIAs. We
validate this approach by correlating waterborne levels of these hormones
with the circulating levels obtained from plasma samples of the same
animals. Waterborne hormone levels correlate strongly with plasma values
for E2 (r=0.87), T (r=0.61), P (r=0.801) and PGF (r=0.736). This technique
can be applied in any aquatic species and will serve as a powerful tool for
elucidating the hormonal regulation of behavior.
P1.21 KIMOKEO, Bethany K.*; SZABO, Zoltan; SAARMAN, Norah P.;
SIMISON, W. Brian; MARTIN-SMITH, Keith; BARROWS, Abby; BAINE,
Mark; LOURIE, Sara; TOONEN, Robert J.; HAMILTON, Healy; University of
Hawaii, Manoa; [email protected]
Taxonomy and Phylogeography of Hippocampus kuda in Hawaii
The spotted seahorse Hippocampus kuda is widely considered a species
complex with poor taxonomic resolution. In addition to the biological
importance, the entire genus of Hippocampus is listed on CITES Appendix II,
so it is crucial that species are indentified accurately when enacting
conservational regulations. Preliminary molecular and morphological data
from throughout the range do not support the conclusion that H. kuda is a
complex, but rather a single morphologically variable species with a deep
evolutionary history. In Hawaii, as with other populations throughout the
Pacific, there is debate on the taxonomy of H. kuda, with a range of opinions
being expressed from recent aquarium introduction to distinct species. The
purpose of this study was to determine if populations of H. kuda in Hawaii
are in fact an endemic or not and if not to generate hypotheses for the
source and timing of Hawaiian colonization. Seventeen H. kuda seahorses
were gathered from sites around the island of Oahu, Hawaii and sampled by
removing tiny portions of skin from the tail. DNA was extracted and
mitochondrial Cytochrome b and 16S genes were sequenced to reveal that,
unlike any other location sampled to date, all 17 seahorses were of the
identical haplotype. Haplotype diversity (h) of H. kuda throughout the
Indo-Pacific excluding Hawaii averaged 0.72 compared to a haplotype
diversity of 0.0 in Hawaii. Based on a range-wide survey, the Hawaiian
haplotype appears unique to Hawaii, but well within the H. kuda lineage, and
is one mutation removed from a common haplotype found in Japan and the
Phillipines. These data indicate that the spotted seahorse in Hawaii is H.
kuda but we cannot infer the age or origin of colonization with these data.
P2.65 KING, HM; NEUBARTH, N*; HALE, ME; Univ. Chicago;
[email protected]
Gait diversity in juvenile labroid fishes
Juveniles of a number of labroid fish species, specifically pomacentrids,
scarids, and labrids, use pectoral fin-based locomotion during steady
swimming. At low speeds they alternate the pectoral fins and they use
synchronous pectoral fin movement at high speeds. Above a critical speed
they tuck the fins and power swimming with axial bending alone. We
examine swimming gaits in juveniles of a related group, the cichlids. Cichlids
also belong to the suborder Labroidae, and their morphological diversity
provides opportunities to examine locomotor variation across a diverse range
of morphologies and ecologies. We hypothesized that juvenile
Labeotropheus sp. would use the same locomotor modes as juveniles of
other members of Labroidae. Young fish were obtained from a local breeder.
Fish were filmed at 250Hz in a flow tank at a range of speeds. A ventral view
was used to determine fin/axial patterns and a lateral view was used to
determine the location of the fish in the water column. Juvenile
Labeotropheus exhibited an alternating pectoral fin gait at low speeds and
transitioned to a synchronous pectoral fin gait at higher speeds. Both gaits
were coordinated with axial undulation. In the alternating gait, pectoral fin
movement was 180 out of phase with caudal bending. During synchronous
pectoral fin movement, each tail beat cycle was associated with two pectoral
fin beats so that each pectoral fin was alternately in phase and 180 out of
phase with caudal bending. While there are similarities between the pectoral
fin gaits of juvenile Labeotropheus and other labroid species, coordination of
the pectoral fin with the body axis differs markedly indicating that there is
considerably more diversity of swim coordination patterns in juvenile labroids
than previously described. Supported by NSF grant IBN0238464 to MEH.
P3.65 KIVELL, TL*; KRAMER, EM; WUNDERLICH, RE; Duke University,
James Madison University; [email protected]
Aye-aye hand posture and loading of their specialised digits during
quadrupedal locomotion
Primate hands are often subject to heavy loads during quadrupedal
locomotion. Primates using gaits or substrates in which these loads are
particularly high will typically either (1) possess morphology that ameliorates
potentially high loads (e.g., shorter, more robust digits in terrestrial
cercopithecoids) or (2) use behavioral modifications to prevent high loads
(e.g., knuckle-walking or fist-walking in great apes). Aye-ayes (Daubentonia
madagascariensis) are unique in having exceptionally long, slender fingers
specialized for foraging yet the frequency with which they engage in
head-first descent is predicted to increase loads on their hands. Little is
known about how aye-ayes cope with this seemingly contradictory
morphology and locomotion. Behavioral studies suggest that aye-ayes curl
their fingers during horizontal and declined locomotion, placing all of the
forelimb load on the palm (Oxnard et al., 1990) but other research has shown
that this is not always the case (Krakauer et al., 2002). We investigated hand
and digit load in aye-ayes during horizontal, ascending and descending
quadrupedal locomotion. Four aye-ayes walked along a horizontal and
inclined (30) flat substrate with an EMED-ST pressure mat imbedded within
the substrate. Kinematic data were collected by videotaping from the lateral
view. Forelimb force and pressure increased during head-first decent and
decreased during ascent relative to horizontal locomotion. Aye-ayes rarely
load their digits on any substrate, especially during head-first descent. Our
results show that aye-ayes have modified their behavior by freeing their
digits from forelimb loads, especially when descending inclined substrates, to
accommodate their highly specialized hand morphology.
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P3.151 KLEIN, T. A.*; ROSTAL, D. C.; WILLIAMS, K. L.; FRICK, M. G.;
PAIGE, J. I.; Georgia Southern University, Caretta Research Project, Ceretta
Research Project, U.S. Fish and Wildlife Service; [email protected]
Seasonal Variation and Maternal Investment of the Loggerhead Sea
Turtle Caretta caretta
Female loggerhead sea turtles Caretta caretta were studied on WASAW and
Blackbeard Island National Wildlife Refuge and in 2008 nesting season.
Nesting activity occurred from May until early August. Nest hatching occurred
from July to September. The incubation period for loggerheads in Georgia is
typically ~60 days. A total of 30 different nesting females and different
aspects of their nests were studied (10 early, 10 mid, 10 late season nests).
Nest depth, clutch size, egg size, mean nest temperature, and hatchling size
were compared. Temperature data loggers were placed in the center of the
nests and temperature was recorded every 2 hours until hatching occurred.
Twenty eggs were measured from the 30 nests. Six eggs per clutch per
clutch were collected for composition analysis from WASAW Island. Nests
that were expected to hatch were monitored for hatchling emergence. Upon
emergence, the straight carapace length, width, and depth for up to 20
hatchlings was recorded from all nests with data loggers. It has been
observed that while larger females tend to have larger eggs and clutches,
that within females, egg size decreases as season progresses while clutch
size remains the same. The measuring of egg and hatchling components
could shed light on how biological and physical traits of loggerhead nest
environments affect embryonic development.
P1.130 KLOHR, RC; KRAJNIAK, KG*; Southern Illinois Univ. Edwardsville;
[email protected]
The Systematic Effects of Neurochemicals on the Alimenry Canal of the
Earthworm Lumbricus terrestris
In this study we examined the effects FMRFamide and acetylcholine on each
individual segment of the alimentary canal. Each region was carefully
dissected, attached to a transducer and suspended in a worm saline tissue
bath. A series of applications of these drugs were administered at
concentrations (1 pM to 10 M), and the percent change in amplitude and rate
were measured and recorded. In the pharynx neither acetylcholine nor
FMRFamide caused reproducible data. Treatment of the esophagus with
FMRFamide elicited an excitatory response in amplitude with a concentration
(0.01 to 1 nM) and a decrease in amplitude at concentration (10 nM to 1 M).
The esophagus showed no change in rate except at 100 nM FMRFamide
when it was excitatory in each trial. The crop and gizzard, examined
separately, each showed a concentration dependant excitatory reaction in
both rate and amplitude to increasing concentrations of FMRFamide (1 nM to
10 M). The same peptide applied to the intestine had an inhibitory effect in
amplitude (0.01 nM to 1 M) with no change in rate. Acetylcholine applied to
the esophagus caused a biphasic response that was excitatory in amplitude
at low concentrations (0.01 to 0.1 nM) and an inhibitory at moderate
concentrations (1 to 10 nM) followed by another excitatory response at high
concentrations (100 nM) before becoming inhibitory again. The rate showed
no change throughout the experiments until the neurotransmitter eliciting an
excitatory response at higher concentrations (100 nM to 1 M). The response
to acetylcholine of the crop and gizzard was excitatory for both amplitude
and rate with a threshold of 10 nM. The intestine showed an overall inhibitory
effect when acetylcholine was applied.
P3.76 KNUTIE, S.A.*; PEREYRA, M.E.; University of Tulsa;
[email protected]
The relationship between stress hormones and life history strategies
during the non-breeding season in three species of cardueline finches
Birds residing in temperate areas during the winter are often confronted with
unpredictable weather conditions, reduced resource availability, and shorter
days leaving less time to forage. The physiological and behavioral changes
necessary to cope with these conditions are mediated in part by
glucocorticoids, which enable survival and help increase fitness. Elevated
corticosterone during periods of food deprivation or adverse weather events
are often associated with increases in foraging and locomotor activity, which
may translate into local irruptive movements in some species. Several
species of cardueline finches can be found wintering in the south-central
Great Plains, a region characterized by highly unpredictable and somewhat
extreme conditions. Two of these species, the pine siskin (Carduelis pinus)
and purple finch (Carpodacus purpureus) are nomadic, rarely returning to the
same wintering areas in successive years. They often partake in sporadic
irruptive migrations, which may be related to exogenous cues such as
decreased resource availability and adverse weather events. Other species
of cardueline finches such as the American goldfinch (Carduelis tristis) are
only semi-nomadic during the winter. We investigated the relationship
between size, body condition and corticosterone levels (baseline and acute
response to stress) in relation to season, annual cycle, and adverse weather
events in purple finches, pine siskins, and American goldfinches. In
December 2007, Oklahoma experienced a severe ice storm, which
destroyed or damaged large numbers of trees. Blood samples were collected
the days before, during, and following the storm. Differences in stress
physiology between the three species of cardueline finches during the
non-breeding season will be discussed.
P1.143 KOBEY, RL*; HOSHIZAKI, DK; GIBBS, AG; Univ. of Nevada, Las
Vegas, NIDDK, National Institutes of Health; [email protected]
The Effect of Melanization on Desiccation Resistance and
Thermotolerance in Drosophila melanogaster
Previous research with the genus, Drosophila, has identified variations in
cuticle melanization along gradients of elevation and latitude. Melanization of
the cuticle is the result of incorporation of quinones into the cuticle and
produces a darker-body phenotype. These quinones react to form cross-links
between proteins in the cuticle and may also be polymerized to form
melanin. It has been hypothesized that melanization is an adaptation to both
low-temperature stress and desiccation stress (water stress). Cross-linking of
proteins may make the cuticle more hydrophobic, thus reducing the rate of
transpiration through the cuticle. The darker-body phenotype associated with
melanization is also hypothesized to increase cold hardiness by allowing the
animals to absorb more heat from solar radiation. Evidence in favor of this
hypothesis has been obtained for larger insects, such as butterflies and
beetles, but the hypothesis has not been tested in insects as small as
Drosophila. We are testing mutations that produce lighter or darker body
phenotypes to determine if melanization contributes to desiccation resistance
and/or cold hardiness in Drosophila melanogaster. Supported by NSF award
IOS-0719591 to D.K.H.and A.G.G.
e256
P3.71 KOMAN, James, S*; TOMANEK, Lars; California Polytechnic Univ.,
San Luis Obispo; [email protected]
Environmental Proteomics: Acute salinity stress in the marine model
organism Ciona savignyi.
The ascidian Ciona savignyi, a model marine invertebrate organism, was
exposed to hyposaline conditions to analyze tolerance toward hyposaline
stress. C. savignyi is a species of sea squirt commonly found on pilings of
harbors and marinas in the northeast Pacific. Heavy winter rains and
subsequent run-offs expose C. savignyi to changing salinity conditions. C.
savignyi is an ideal organism for study as its genome has been sequenced
and annotated, and as a chordate it is a close relative to vertebrates.
Tracking the global changes in protein expression in C. savignyi is a pivotal
step in describing the physiological processes that protect animals against
cellular damage in response to acute salinity stress. The organisms were
exposed to decreasing salinities, 100%, 85% and 70% (sea water), for 6
hours. After exposure to hyposaline conditions, specimens were brought
back to 100% salinity to recover for 4 hours. Organisms were dissected to
remove the tunic, and 2D SDS-polyacrylamide gel electrophoresis was
performed on the whole organism to separate proteins and generate protein
expression profiles. Gels were scanned and analyzed with a 2D gel image
analysis software (Delta2D, DECODON) to compare expression levels of
proteins between treatment groups and the control (100% sea water).
Comparisons using a 1-way ANOVA with a p-value of 0.05 led to the
identification of 19 spots divided among three activity clusters. It is
hypothesized that these proteins play a role in the tolerance toward
hyposaline stress in C. savignyi. Further analysis with MALDI TOF-TOF
mass spectrometry will allow for the identification of these proteins and help
us determine which role they play in the physiological response to
decreasing salinity.
P3.146 KORINE, C; DANIEL, S; PINSHOW, B*; Ben-Gurion University of the
Negev; [email protected]
Frugal energy use by Hemprichs long-eared bats () Otonycteris
hemprichii) during pregnancy and nursing
We hypothesized that the energy balance of breeding female Hemprich's
long-eared bats Otonycteris hemprichii bats is shaped by a trade-off between
the requirements for embryo or pup growth, and the mothers own need to
use torpor to save energy and water. We used indirect calorimetry to
measure metabolic rates (MR) of pregnant and nursing bats over a range of
ambient temperatures. Mass specific MR of euthermic bats decreased from
22.95 mWg-1 to 5.04 mWg-1 as ambient temperature increased from 15 C to
33 C, and was not different from that of non-reproductive female bats. We
estimated daily energy expenditure (DEE), taking into account the costs of
foraging and roosting in pregnant and nursing bats. DEE increased by 54%,
from late pregnancy (54.74 kJday-1) to peak lactation (84.23 kJday-1). This
increase was smaller than the 78% - 182% increase measured with doubly
labeled water in other insectivorous bat species. The proportion of DEE
invested in maternal care by mother bats was about 30%, in the range found
in other insectivorous bat species (28% - 32%). Our data indicate that the
increase in DEE of female O. hemprichii during reproduction is relatively
small compared to other insectivorous bats, which may be advantageous in
desert habitats.
P2.39A KOSKI, M*; AYERS, T; SCOTT, R; University of Michigan, Ann
Arbor; Northern Arizona University, Flagstaff, Northern Arizona University,
Flagstaff; [email protected]
Genetic and morphological analysis of Hanging Garden Endemic,
Anticlea vaginata and Widespread Montane Species, A. elegans
We sequenced the ITS and trnL-F spacer regions of four southwestern
Anticlea taxa with emphasis on A. vaginata and A. elegans var. elegans. We
performed a cladistic analysis to place A. vaginata in a phylogenetic context
with its congeners and to compare it to its putative sister taxon, A. elegans.
The phenogram based on ITS showed no variation between taxa sequenced.
The trnL-F cladistic analysis showed only minor differentiation between
populations. The phylogenetic analysis suggest that the ITS and trnL-F
regions are not sufficiently variable for discerning evolutionary relationships
at the species level for southwestern Anticlea taxa and that these species
may have shared a common evolutionary history. It may also suggest that, if
A. vaginata is distinct from A. elegans, the speciation event was recent in
evolutionary history. Genetic data was compared to the results of a
morphometric analysis of six characters. The morphometric analysis showed
that only leaf width varied significantly. Furthermore, the range of variation
for most morphological traits of A. vaginata and A. elegans overlapped.
Genetic and morphological data do not support recognition of A. vaginata
from A. elegans. If A. vaginata is to be recognized as a taxon, the subspecific
level may be most appropriate.
P3.167 KOSTELANETZ, Sophia A.*; DICKENS, Molly J.; BUTLER, Luke K.;
ROMERO, L. Michael; Tufts University; [email protected]
Effects of chronic stress during molt on the heart rate and heart rate
variability of European starlings
Chronic stress (CS) is the physiological condition of over-stimulation of
coping mechanisms to chronically repeated noxious stimuli. Previous studies
have looked at glucocorticoid levels during molt and stress. This is the first
study to investigate the effect of chronic stress during molt on heart rate (HR)
and heart rate variability (HRV) in captive European Starlings (Sturnus
vulgaris). Each of 16 birds was implanted with a heart rate monitor to collect
electrocardiograms. Three weeks after molt began, all birds were exposed to
18-days of chronic stress. Changes in HR and HRV were analyzed during
two daily time periods: daytime and nighttime. Preliminary data show that
during the daytime, there were no statistical changes in HR. However, HRV
decreased with the onset of a molt, with no subsequent change during CS.
The decrease in HRV indicates a shift from parasympathetic to sympathetic
control of HR with the onset of molt, with the same balance remaining
throughout CS. In contrast, during the nighttime HR goes up with the onset of
molt, with no subsequent change during CS. HRV did not change both with
the onset of molt and throughout CS. Because there was no decrease in
HRV, the data suggests that the increase in HR is being driven by changes
in parasympathetic not sympathetic input. Previous data have shown that CS
has a dramatic impact on HR and HRV of non-molting birds, but here we
show that molting birds have an attenuated response to CS.
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P2.147 KRANS, JL*; PATERSON, BA; Mount Holyoke College;
[email protected]
Hysteresis in Force Production of Bodywall Muscle of Larval Diptera
We describe neuromuscular hysteresis - a strong dependence of muscle
force production on recent motoneuron activity - in the bodywall muscles of
larval Diptera, including Sarcophaga and Drosophila. In semi-isolated
nerve-muscle preparations, we show that force produced by a train of nerve
impulses at a singular rate is significantly different than that produced by the
same train of stimuli when preceded by a brief (< 200 ms) high frequency
burst of impulses. The increased force could not be explained by a change in
electrical junction potentials (EJPs) between the two impulse trains; EJPs
were not statistically different before or immediately after the high frequency
burst. Both single muscle and semi-intact preparations exhibited hysteresis
similarly, suggesting that the mechanics of non-contractile tissue is not
central to the mechanism of hysteresis. Hysteresis was most dramatic at low
impulse rates - yielding ~100% increase in force predictions based on
constant-rate impulse trains - and decreased in a consistent manner as
impulse rate increased. The frequencies at which hysteresis was greatest
correspond well to the range observed under normal physiological
conditions. In an attempt to more closely model physiological activation, we
modulated nerve frequency in a sinusoidal fashion across rates close to
those during normal, rhythmic behavior. Each successive cycle of these
modulations yielded a slightly decreased, but still notably positive hysteretic
force loop. These force loops illustrate the difference between force
produced while frequency was increasing and that produced while it
decreased. Our hope is that this initial characterization provides a foundation
upon which the underlying mechanism of this non-linearity can be
investigated.
P2.159 KRIENGWATANA, B.P.*; AN, Y.; NEWMAN, A.E.;
MACDOUGALL-SHACKLETON, E.A.; MACDOUGALL-SHACKLETON, S.A.;
University of Western Ontario, London ON, University of British Columbia,
Vancouver BC; [email protected]
Melatonin, Aggression, and Social Dominance in the Black-Capped
Chickadee
Non-breeding black-capped chickadees (Poecile atricapillus) form linear
dominance hierarchies in the winter. Dominants establish and maintain
status by repeatedly directing aggression towards subordinates. The
mechanism underlying dominant-subordinate aggression is unclear, as
testes are regressed and testosterone levels are assumed to be basal in
non-breeding chickadees. Plasma levels of melatonin, an idolamine
produced by the pineal gland in the absence of light, are higher during
non-breeding conditions, and treatment with exogenous melatonin has been
shown to facilitate aggression in some animals. This study investigated the
role of melatonin in black-capped chickadee dominant-subordinate
aggression and its possible effects on social status. Seasonal and circadian
changes in plasma melatonin and testosterone concentrations in isolated,
captive chickadees were measured in blood samples collected at 5 different
times throughout the day and night, during breeding (16:8 L:D) and
non-breeding (10:14 L:D) condition. To determine the relationship between
melatonin and establishing and maintaining status, unfamiliar subjects were
allowed to interact in pairs and blood was collected immediately after the
interaction, 24 hours, and 10 days later. Future research will investigate
whether exogenous melatonin treatment can increase aggression and
subsequently alter social status. These studies thus test the hypothesis that
dominance-related aggression is mediated by seasonal and individual
differences in melatonin.
P3.106 KRUMM, J.L.; Widener University; [email protected]
Evidence of senescence in a branchiopod crustacean, Branchinecta
lindahli, living in a highly unpredictable environment
The longevity of ephemeral aquatic environments can be highly
unpredictable due to variations in precipitation, temperature, and humidity.
Small pools are especially sensitive to environmental conditions and are
typically colonized by animals adapted for rapid maturity and reproduction.
Selection for early reproduction can have negative effects on other traits
such as late reproduction and longevity, resulting in senescence.
Branchinecta lindahli is a species of fairy shrimp that commonly colonizes
small disturbed pools, such as roadside ditches. These pools are known to
dry unpredictably, occasionally killing actively reproducing populations of B.
lindahli. It is unknown if B. lindahli females exhibit reproductive senescence.
Daily egg production in female B. lindahli was measured in the laboratory to
determine if senescence occurs, and if females display a trade-off between
early reproduction and late reproduction and survival. Preliminary results
indicate that egg production decreases towards the end of the lifespan in a
subset of female B. lindahli.
P3.75 KULKARNI, SB*; MOSKALIK, CL; GOMEZ-MESTRE, I; BUCHHOLZ,
DR; Univ. of Cincinnati, Cincinnati, Estacion Biologica de Donana, Spain;
[email protected]
Decreased phenotypic plasticity in a trait undergoing extreme selection
Directional selection can cause the mean value of a trait averaged across
environments to change. However, the effect of such selection on phenotypic
plasticity of the trait is not clear because plasticity and mean trait values may
be controlled by different mechanisms. The spadefoot toad Scaphiopus
couchii has evolved extremely short larval periods to survive highly
ephemeral desert pools from ancestors using long lasting pools. To examine
evolutionary change in plasticity in age and size at metamorphosis in
response to pond duration, we reared individual tadpoles of Sc. couchii and
its relatives Spea multiplicata and Pelobates cultripes in the lab at two water
volumes and two temperatures starting at three developmental stages. All
species accelerated development in the low water level treatment, but at the
expense of reduced growth in Sp. multiplicata and Pb. cultripes, but not Sc.
couchii. The percent increase in development rate and percent decrease in
growth rate due to low water volume were greater in Spea and Pelobates
compared to Scaphiopus at all stages and temperatures. Our results indicate
that Sc. couchii has lower plasticity in age and size at metamorphosis in
response to small water volumes compared to other two species.
Nevertheless, Sc. couchii has remarkable habitat tracking in nature to
achieve the largest body size possible for a given short duration pond, often
leaving the pond the day before pond drying. Thus, our results do not favor
the idea that ephemeral breeding ponds of Sc. couchii are predictably short
thereby favoring reduced plasticity Rather, our results support the hypothesis
of a mechanistic connection between regulation of larval period trait values
and plastic responses to the environment.
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P3.201 KULLEPERUMA, Kethika*; JIMENEZ, Lizandra; DOOLEY, James K.;
Adelphi University, Mt. Sinai Cytogenetics Lab; [email protected]
preliminary cladistic analyses of the tilefishes, percoidea:
malacanthidae and branchiostegidae, based on the mitochondrial
genes 16s and cyt.b genes
Two hypotheses exist: 1. tilefishes are monophyletic and belong to a single
family (Malacanthidae) and two subfamilies Malacanthinae and
Branchiosteginae and 2. the fishes are polyphyletic and warrant being
assigned to the two families Malacanthidae and Branchiostegidae as a
former morphological revision proposed. Fossil records date the group to the
mid-Eocene 45 Ma. Tilefishes are a primitive benthic percoid group of fishes
found world-wide in tropical to subtropical waters. They consist of five genera
and 42 nominal species. These fishes are dimorphic, with one group, the
elongate sandtilefishes, found in shallow to moderate sandy bottom depths
(20-117m) while the other robust-bodied tilefishes are found in mud-sand
bottom at greater depths (150-500m). Thus far, partial 16S (600 bp) and
cyt.b (1000 bp) genes of 22 species have been sequenced for the first time
and analyzed using PAUP. and MrBayes to generate a maximum parsimony
(MP) and Baysian trees, respectively. PAUP maximum likelihood (ML) and
neighbor-joining (NJ) analyses produced similar trees. The beryciform fish
Beryx splendens was used as the outgroup. Baysian analysis produced five
clades with all but Lopholatilus and Hoplolatilus formed as generic specific
clades. Hoplolatilus(12 extant species) was shown to consist of 2 clades
somewhat supporting , the present Hoplolatilus sub generic arrangement.
MP analysis also produced a five clade tree with all but Malacanthus and
Hoplolatilus forming generic specific clades. Preliminary conclusions based
upon molecular data support the hypothesis that the tilefishes are
polyphyletic.
P1.41 KUMBUREGAMA, S*; WIKRAMANAYAKE, A; University of Hawaii at
Manoa, University of Miami; [email protected]
Evolution of germ layers: insight from early Wnt signaling in a
cnidarian
The animal-vegetal (AV) axis, a character seen in most bilaterian eggs is
crucial for germ layer segregation and gastrulation. This axis most likely
played an important role in evolution of pattern formation in animal embryos,
but its evolutionary origins are unknown. We use cnidarians, a sister group to
bilaterians, to gain insight into evolution of the AV axis. In Nematostella
vectensis, the AV axis is specified by localization of the Wnt pathway
regulator Dishevelled (Dsh) to the animal pole of unfertilized eggs. Dsh
activates Wnt/catenin signaling segregating endoderm from ectoderm.
Additionally, Dsh signaling in the Wnt/PCP pathway regulates
morphogenesis during gastrulation in Nematostella. We will discuss
mechanisms that localize Dsh protein to the animal pole and how this protein
selectively regulates cell fate specification and morphogenesis in
Nematostella. Our results support the hypothesis that Wnt signaling played a
critical role in germ layer segregation and gastrulation during animal
evolution.
P3.26 KUROCHKIN, IO*; IVANINA, AV; EILERS, S; SOKOLOVA, IM;
University of North Carolina at Charlotte, Charlotte, USA, Hochschule
Bremen, Bremen, Germany; [email protected]
Effects of cadmium exposure on mitochondrial response to
environmental anoxia and re-oxygenation in eastern oysters
(Crassostrea virginica).
Intertidal organisms are periodically exposed to limited oxygen availability
followed by reoxygenation during tidal cycles, often in the presence of other
stressors such as metal pollution, but the effects of these stressors on their
metabolism are not well understood. We have studied the effects of anoxia
caused by air exposure (1-6 days) with subsequent reoxygenation on
mitochondrial function and nitric oxide (NO) levels in control oysters and in
oysters exposed to 50 ug L - 1 of cadmium (Cd) for 30 days. Oxygen
consumption of isolated mitochondria respiring on pyruvate, succinate, and
TMPD decreased during air exposure but increased well above the normoxic
levels during the first 6h of re-oxygenation in control (not exposed to Cd)
oysters. Respiratory control ratios (RCR) decreased during anoxia and
recovery in control oysters indicating a decrease in mitochondrial efficiency.
In Cd-exposed oysters, a decrease in mitochondrial respiration or RCR
during hypoxia was not significant, and the respiration burst in first hours of
reoxygenation was completely abolished. NO content was significantly
decreased and remained stable after 3 days of air exposure returning to the
initial levels after 6 h of normoxic recovery in control oysters. NO level
recovery was significantly delayed in Cd exposed oysters during recovery
what correlated with the significantly lower activity of nitric oxide synthase in
Cd-exposed oysters. These data suggest that cadmium may have an
important effect on mitochondrial metabolism and on metabolic adaptations
to periodical anoxia and reoxygenation during the tidal cycle in marine
bivalves. Supported by NSF CAREER (IBN-0347238).
P1.55 KUSHNER, S.A*; GIBB, A.C; ARENA, A; FERRY-GRAHAM, L.A;
Mansfield University of Pennsylvania, Northern Arizona University, Moss
Landing Marine Laboratory; [email protected]
Four-eyed fish (Anableps anableps)use the same jaw-opening
movements to produce a distinct prey-capture behavior across
environments
Four-eyed fish, Anableps anableps, are native to northern South America
and inhabit mangrove swamps. They swim at the water's surface so that their
eye is bisected by the air-water interface, which allows a simultaneous view
of both aerial and aquatic environments. A. anableps feed both in the water
on aquatic organisms, and out of water on intertidal, terrestrial and even
low-flying aerial organisms. In the laboratory, A. anableps were offered prey
items (crickets) held on forceps both above (aerial) and below the surface of
the water (aquatic). Using high-speed digital-imaging, we recorded and
quantified five displacement variables and five timing variables associated
with the head and jaw movements during the mouth-opening phase of prey
capture in both environments (e.g. maximum gape, time to maximum jaw
depression, etc.). Surprisingly, the relative timing and magnitude of these
movements were statistically indistinguishable across environments.
However, the time between mouth opening and prey contact was longer and
strike velocity was more rapid when A. anableps were feeding on prey held
above the surface. These results suggest that a single set of cranial
movements is used to produce mouth opening in both environments, but the
predator is physically closer to the prey-item when these movements occur
underwater. The ram-suction-index (RSI) indicates that the movements of
the neurocranium and jaws produce effective suction during aquatic
feedings, but the same movements result in a ram-based prey capture during
aerial feedings.
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P1.131 LAGARES, E.*; DAHNIEL, S.; CARROLL, M.A.; CATAPANE, E.J.;
Medgar Evers College; [email protected]
Effects of Calcium Disodium EDTA on the Neurotoxicity of Manganese
on Biogenic Amines in the Nervous System and Innervated Organs of
Crassostrea virginica
Manganese (Mn) is a neurotoxin which induces Manganism, a Parkinson-like
disease, in individuals exposed to high airborne levels. Exposure to high
levels of Mn for long periods may cause mental and emotional disturbances,
and slow and clumsy body movements. Manganism occurs because Mn
injures dopamine neurons in the brain involved in control of body
movements. Recently, p-aminosalicylic acid (PAS) has been shown to
alleviate symptoms of Manganism in humans, but its mechanism of action is
unknown. The oyster, Crassostrea virginica, possesses a dopaminergic
system innervating the gill and regulating lateral ciliary activity. Previously we
showed PAS protected dopamine neurons against the neurotoxic effects of
Mn. PAS has anti-inflammatory and chelating ability. The ability of PAS to
ameliorate symptoms of Manganism is postulated to be related to its
chelating actions. To test this, we treated C. virginica with Mn and calcium
disodium EDTA (EDTAca), a chelating agent. C. virginica were exposed to
500 µM of Mn with and without 50 or 500 µM of EDTAca for 3 days. Controls
were similarly treated without Mn or EDTAca. Biogenic amines were
measured by HPLC techniques with fluorescence detection. Cerebral
ganglia, visceral ganglia and gill were dissected, weighed, homogenized,
centrifuged, filtered and injected into a Beckman HPLC system with a
Phenomenex Gemini µ C18 column and a Jasco FP 2020
Spectrofluorometer with a 50 mM acetate buffer mobile phase. EDTAca
treatments protected the ganglia and gill against the effects of Mn. These
findings may provide insights into the actions of Mn and PAS in treatments of
Manganism. This work was supported in part by grants 2R25GM06003-05 of
the Bridge Program of NIGMS, 0516041071 of NYSDOE, 0622197 of the
DUE Program of NSF and 0420359 of the MRI Program of NSF.
P2.102 LAKE, D.T.*; FRICK, M.G.; RAWSON, P.D.; ZARDUS, J.D.; The
Citadel, Charleston, SC, Caretta Research Project, Savannah, GA,
University of Maine, Orono; [email protected]
Host-specific morphological plasticity obscures species boundaries in
a commensal barnacle
Barnacles are familiar shoreline animals; however, less well known are the
many species that live attached to other animals as obligate commensals.
The four recent species of barnacles in the genus Chelonibia as adults are
only found attached to marine vertebrates, crustaceans and molluscs: C.
testudinaria and C. caretta attaching to sea turtles, C. manati to manatees,
and C. patula to crabs and snails. Sharing similarities in form but varying in
size and growth habits, these taxa have been deemed separate species at
least since Darwins 1854 monograph on the Cirripedia. However, despite
morphological differences these barnacles may in fact constitute a single
species that exhibits different forms depending on host affiliation. To test this
hypothesis, we compared genetic variation between specimens of Chelonibia
collected from sea turtles, crabs, and manatees. DNA was extracted using
commercially available kits and a portion of the mitochondrial gene
cytochrome oxidase I (COI) was amplified through the Polymerase Chain
Reaction (PCR). Resulting sequences were compared and analyzed
phylogenetically. The results support our hypothesis in part, showing low or
no genetic variation among C. testudinaria, C. manati, and C. patula but
significant species-level divergence with C. caretta.
P2.49 LANGSTON, Jennifer; PIRES, Anthony*; Dickinson College;
[email protected]
Regulation of Metamorphosis by Catecholamines in Larvae of the
Polychaete Capitella sp. I
Recent work has indicated that catecholamines regulate the induction of
metamorphosis in primitive and derived gastropods. We have begun to
investigate the distribution of this developmental control mechanism in other
lophotrochozoan taxa, by studying the effects of endogenous
catecholamines on metamorphosis of the polychaete, Capitella sp. I.
Immunolabeling for the catecholamine-generating enzyme, tyrosine
hydroxylase (TH), revealed TH-immunopositive cells in apical regions of the
prostomium, in the circumesophageal nerve ring, underlying the prototroch
and columns of setae, and in the pygidium. Catecholamine biosynthesis was
depressed by the TH inhibitor, α-methyl-DL-m-tyrosine (α-MMT) and
enhanced by the catecholamine precursor, L-DOPA. To verify effects of
these drugs, norepinephrine and dopamine were quantified by high pressure
liquid chromatography. Endogenous dopamine was depleted by α-MMT and
enhanced by L-DOPA; norepinephrine was depleted by α-MMT but was
unaffected by L-DOPA. After drug treatments, metamorphosis was assayed
in response to a natural cue (an extract of sediment from adult habitat).
Frequency of metamorphosis after 48 h was significantly lower in larvae
treated with α-MMT and in larvae treated with L-DOPA, than in artificial
seawater controls. Therefore, consistent with studies in several gastropod
species, depletion of endogenous catecholamines inhibited metamorphosis
of Capitella sp. I. Enhancement of endogenous catecholamines by L-DOPA
failed to potentiate metamorphosis in this study, consistent with earlier
findings in a patellogastropod, but unlike results obtained in more derived
gastropods. The possible origins of modulation of metamorphosis by
catecholamines are discussed.
P2.103 LARSON, PM*; RAABIS, S; BRICK, A; CORRIVEAU, J; HALL, H;
LENIHAN, P; MAY, S; St. Anselm College; [email protected]
Intraspecific variation in chondrocranial morphology of wood frog
tadpoles (Rana sylvatica)
This study investigates intraspecific variation in chondrocranial morphology
among tadpoles derived from three wood frog (Rana sylvatica) egg masses
collected from a single vernal pool. Results indicate that chondrocranial
shape differs significantly among samples of tadpoles derived from the three
egg masses, even when reared under identical laboratory conditions and
matched for size and developmental stage. Thus, these results suggest that
the variation observed is genetic in origin, and not simply due to
environmental influences on the development of the tadpole
chondrocranium. Primary areas of variation include the width of the muscular
process of the palatoquadrate, the size of the palatoquadrate articular
process, the distance between the upper jaw articulation sites (= gape
width), and the anatomy of the posterior portion of the palatoquadrate. Given
the close association of these structures with anatomical elements critical to
feeding and respiration (e.g., mandibular and hyoid arch muscles, jaw
cartilages), all of these areas represent functionally important regions of the
chondrocranium. Although little is known about the potential selective
advantages (if any) of any of these anatomical variations, or their
heritabilities, the existence of discrete, presumably genetically based
intraspecific variation at this small scale satisfies one of the major
requirements necessary for natural selection to act as an agent driving
interspecific changes in tadpole morphology.
e260
P2.23 LAWLER, RR*; CASWELL, H; Boston University, Woods Hole
Oceanographic Institution; [email protected]
Conservation biology of Verreaux's sifaka (Propithecus verreauxi
verreauxi): Prospective and retrospective perturbation analyses.
In this study, we employ two separate analyses in order to understand how
population growth rate (pgr) responds to changes in the population's vital
rates (rates of survival, growth, and fertility). Prospective analyses are
commonly used to inform management decisions and ask the question: how
would pgr change, given a change in one or more of the vital rates?
Retrospective analyses examine how variation in pgr is expressed as a
function of the (co)variation of the vital rates. This type of analysis can reveal
how year-to-year variation in growth, survival, and fertility contributes to
variation in pgr. Our prospective analysis was achieved by developing a
time-invariant, five-stage matrix model using 17 years of data collected on a
wild population of Verreaux's sifaka. Using this matrix model, we calculated
sensitivity and elasticity values that capture the prospective dependency of
how pgr would change, given a change in a vital rate. Our retrospective
analysis draws from matrix models developed from the first half and last half
of the 17-year dataset. From these matrices, we decompose variation in pgr
into contributions from the variation in the vital rates. Our results show that
pgr is most sensitive to transitions into maternity, and less dependent on
survival and growth of reproductively immature animals. We also find that
variation in survivorship of mothers contributes the largest amount to
variation in pgr. Our results suggest that the long-term viability of the sifaka
population depends on recruitment of females into motherhood and is less
dependent on the survival of pre-reproductive females.
P3.152 LEBLANC, A.M.*; WIBBELS, T.; Univ. of Alabama, Birmingham;
[email protected]
Effect of fluctuating temperature on a turtle with
temperature-dependent sex determination
A variety of previous studies have characterized the effects of incubation
temperature on reptiles with temperature-dependent sex determination
(TSD). However, the majority of those studies utilized constant temperatures
in laboratory incubators. It has been suggested that data from constant
temperature studies may not be a good predictor of sex ratios for natural
nests that experience fluctuating temperatures. This has significant
implications regarding the biology and conservation of reptiles with TSD. The
current study has addressed this issue in the red-eared slider, Trachemys
scripta, a turtle with TSD. Laboratory incubators were used to generate
specific daily temperature fluctuations of 2, 3, or 4oC around the same mean
temperature of 28.2 o C. The sex ratios produced in the fluctuating
temperature experiments were not significantly different from sex ratios of
control groups produced at constant incubation temperatures of 28.2 o C
(p>0.05). Although temperatures fluctuated well into all-male and all-female
producing temperature ranges, significant skewing of the sex ratios was not
observed. The results are consistent with the hypothesis that mean
incubation temperature may be an accurate predictor of sex ratio. These
results have implications for studies addressing the physiological basis of
TSD, as well as for conservation programs attempting to predict sex ratios
based on incubation temperatures.
P1.149 LEDON-RETTIG, C.C.*; CRESPI, E.J.; PFENNIG, D.W.; Univ. of
North Carolina, Chapel Hill, Vassar College; [email protected]
Hormonal Regulation and the Evolution of Novel Feeding Strategies
Feeding strategies are diverse, even among closely related taxa, but little is
known about how organisms shift to a new diet. Adopting a novel diet is likely
stressful for organisms, eliciting hormonal changes that can influence their
development and fitness. However, it is unknown whether consuming a novel
diet elevates the production of corticosterone (CORT, the principle vertebrate
stress hormone). The drastically different larval feeding habits of closely
related spadefoot toads (genera Scaphiopus and Spea) are ideal for
evaluating diet-induced changes in CORT. Scaphiopus larvae, like most
anurans, feed on detritus and plankton. In contrast, some Spea larvae have
also evolved the ability to specialize on macroinvertebrate prey, such as fairy
shrimp. Because Scaphiopus is Spea's closest sister group, and because
they share the same feeding strategy as most other anuran larvae,
Scaphiopus is likely similar to ancestral Spea in its feeding strategy as well
as its diet-induced hormonal responses. Thus, by using Scaphiopus as a
substitute for ancestral Spea, we can infer what hormonal changes must
have evolved in order for Spea to make the transition to its modern diet of
shrimp. Using radioimmunoassay we quantified concentrations of CORT in
both genera, when both were either fed the derived (shrimp) or ancestral
(detritus) diet. The results from this research will serve as a springboard for
investigations of downstream regulators of hormonal action, such as nuclear
hormone receptor expression.
P1.136 LEE, J.-Y.*; BHATT, D; BHATT, D; CHUNG, W.-Y.; COOPER, R.L.;
Dept of Biology, Univ of KY, Lexington, KY, & Army, Daejun, Republic of
Korea, Univ of KY, Dept. of Chem, Korea Military Academy, Seoul, Republic
of Korea; [email protected]
Pre- & Post-synaptic Actions of Kainate: Negative Feedback at
Glutamatergic Nerve Terminals
Drosophila larval neuromuscular junctions (NMJs) serve as a model for
various gene mutations of synaptically relevant molecules to characterize
synaptic physiology. The molecular sequence of the glutamate receptors
have been described; however, the pharmacological profile of glutamate
receptor subtypes at the NMJ have not been fully elucidated. We present
evidence for self regulation (i.e. negative auto-feedback) at the NMJ in
Drosophila. Based on the pharmacological profile these presynaptic
autoreceptors are likely a kainate subtype of glutamate receptors. Kainate
does not depolarize the muscle, but evoked EPSP dampen when kainate is
present and mini frequency is reduced. Quantal responses show a
decreased amplitude and area under the voltage curve indicative of reduced
postsynaptic receptor sensitivity to glutamate transmission. ATPA, a kainate
receptor agonist, mimics kainate action both pre- and post-synaptically.
Domoic acid, a quisqualate receptor antagonist, blocks the postsynaptic
receptors without depolarizing the muscle, which supports earlier findings of
the muscle containing quisqualate subtype receptors. No effects are seen on
the frequency of spontaneous events in low concentration of domoic acid
which causes a 50% reduction in quantal amplitude. The results suggest a
kainate pre-synaptic auto-inhibitory feedback on evoked release. The
mechanism of action within the presynaptic terminal remains to be
elucidated. The mild direct postsynaptic action of kainate is likely due to
partial antagonist action on the quisqualate receptors.
Funding:NSF-IBN-0131459 (RLC), Univ. KY (JYL), Korean Army & Korea
Military Academy (JYL, WYC).
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P2.43 LEE, E.M.*; MCCAULEY, D.W.; University of Oklahoma, Norman;
[email protected]
Cartilage rescue in a zebrafish mutant following heterospecific
expression of a lamprey SoxE gene
Gene duplication is thought to be a driving force for generating novel
evolutionary traits that have led to increased vertebrate diversity and
complexity. The appearance of neural crest cells in the ancestral vertebrate
has also been proposed to be a characteristic key to the evolution of
vertebrates. Some vertebrate cartilages are derived from migrating
chondrogenic neural crest cells. Expression of Sox9 in these cells regulates
expression of Type II collagen, the major matrix protein in vertebrate
cartilage. Sox9 is one of three SoxE transcription factors that arose as a
result of gene duplication in the vertebrate lineage. Lampreys, the
basal-most extant vertebrates also possess three duplicate SoxE genes,
SoxE1, SoxE2, and SoxE3 whose expression patterns have previously been
described by our group. Here we investigate the functional role of the
lamprey (Petromyzon marinus) gene SoxE1 within the context of zebrafish
(Danio rerio) cartilage development. The chondrogenic function of a SoxE
gene might have been acquired in early vertebrates following duplication of
the ancestral SoxE gene at the base of vertebrates. Here we show that the
jef hi1134 zebrafish mutant missing a functional Sox9a gene and lacking
cartilage, shows partial rescue of cartilage development following heterotopic
expression of lamprey SoxE1 mRNA. Our data suggest that neural crest and
chondrogenic functions of SoxE genes may have arisen prior to SoxE
duplication at the base of vertebrates, but that the chondrogenic role was
likely acquired by different SoxE paralogs present in agnathan and
gnathostome vertebrates.
P2.4 LEININGER, E.C.*; KITAYAMA, K.; KELLEY, D.B.; Columbia
University, New York , NY; [email protected]
The evolution of neuromuscular systems for vocal behavior in the
African clawed frog (Xenopus)
African clawed frogs (Xenopus) vocalize to attract females and mediate
male/male antagonistic interactions. Individual frogs rely on the temporal
characteristics of calls to distinguish sex and reproductive state; these
characteristics (particularly click rate) are also species-specific. To explore
the origins of species differences in vocal signaling, we examined
physiological properties of muscles in the vocal organ of X. borealis (a
species with a slow, simple advertisement call) relative to X. laevis (a
species with a fast, biphasic advertisement call). In X. laevis, female calls are
slow and monotonous relative to male calls, and laryngeal muscle is sexually
differentiated with respect to contractile speed, fiber number, fiber twitch
type, and fiber recruitment. In X. borealis, a species where female calls can
be as rapid as those of males, we report that while larynx weight and
laryngeal muscle fiber size is sexually dimorphic, other characteristics such
as fiber type, fiber recruitment, and the rates at which discrete tension
transients can be produced do not differ between the sexes. This reduced
sexual dimorphism is consistent with the greater overlap in click rate of calls
from male and female X. borealis, compared to X. laevis. One mechanism
that may contribute to reduced sexual dimorphism in X. borealis is reduced
sensitivity to the masculinizing effects of androgen.
P1.140 LEMA, S.C.; Univ. of North Carolina, Wilmington; [email protected]
Isolation and expression patterns of cDNAs for three vasotocin
receptors and an isotocin receptor from a teleost, the Amargosa
pupfish
Arginine vasopressin regulates hydromineral balance, vasoconstriction and
sociosexual behaviors in mammals, and the related hormone arginine
vasotocin has been implicated to play similar roles in birds, amphibians and
teleost fish. While three distinct receptors for vasopressin (V1a, V1b and V2)
have been identified in mammals, only a single receptor has been found in
teleosts. Here, cDNAs for vasotocin receptors were isolated and sequenced
from the Amargosa pupfish (Cyprinodon nevadensis amargosae) - a species
studied previously for vasotocin's role in regulating aggression. Using
degenerate primer PCR and 5'- and 3'-rapid amplification of cDNA ends
(RACE), two full-length cDNAs encoding deduced sequences of 497 and 385
amino acid residues, and a third cDNA encoding a 325 residue partial open
reading frame, were identified. The 497 residue cDNA exhibited highest
identity (49.0-57.4%) to V2-type vasopressin/vasotocin receptors of
mammals and amphibians, and lower identity to V1a (37.8-39.6%) and V1b
(41.1-41.9%) receptors. The cDNA encoding 385 amino acids had greater
identity to V1a-type receptors from mammals and amphibians (58.6-62.6%)
than to V1b (51.5-53.5%) and V2 (38.6-45.0%) receptors. Similarly, the
partial cDNA for 325 residues also showed greater identity to V1a receptors
from mammals (56.7-58.5%) and amphibians (59.5-61.5%), than to either
mammalian V1b (54.7-55.4%) or V2 (40.9-42.1%) receptors. A fourth
full-length cDNA encoding an isotocin receptor of 395 amino acids has also
been identified from this pupfish. Future characterization of the function and
expressional regulation of these receptors will provide new insights into the
evolutionary and functional diversity of the vasotocin/vasopressin and
isotocin/mesotocin/oxytocin receptor families in vertebrates.
P2.14 LEMASTER, MP*; UHRIG, E; MASON, RT; Western Oregon
University, Oregon State University; [email protected]
Temporal Variation in the Female Sexual Attractiveness Pheromone of
the Red-sided Garter Snake, Thamnophis sirtalis parietalis
Female garter snakes produce and express a sexual attractiveness
pheromone during the breeding season that elicits male courtship behavior.
Composed of a homologous series of saturated and mono-unsaturated
methyl ketones, this pheromone is expressed in the skin lipids of females. It
has been observed that female snakes lose their attractivity to males as the
breeding season progresses. Here we present a study designed to
determine whether temporal changes in the quantity and / or quality of the
female sexual attractiveness pheromone are responsible for the observed
loss of attractivity utilizing the red-sided garter snake, Thamnophis sirtalis
parietalis, as a model system. Female red-sided garter snakes were
collected immediately following spring emergence and held under natural
conditions (outdoor arenas) for the duration of the breeding season.
Behavioral experiments demonstrated that females are significantly less
attractive to males within two weeks of emergence from winter hibernacula.
Subsequent chemical analyses revealed a significant qualitative difference in
the relative concentrations of individual methyl ketones comprising the
pheromone profiles between newly emerged females and females two weeks
post-emergence. Together, these results support the hypothesis that
changes in the female sexual attractiveness pheromone are responsible for
diminishing post-emergence female attractivity in garter snakes.
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P1.59 LEYSEN, H.*; DUMONT, E.R.; ADRIAENS, D.; Ghent University,
Belgium, Univ. of Massachusetts, Amherst; [email protected]
Stress distribution and morphological specializations in the feeding
apparatus of a seahorse (Syngnathidae: Hippocampus reidi)
The family Syngnathidae (Gasterosteiformes) encompasses the pipefishes
and seahorses. Syngnathid fishes are characterized by an elongated snout
with small terminal jaws. They are extremely fast suction feeders, with a
feeding strike characterized by a rapid neurocranial elevation accompanied
by an equally rapid retraction of the hyoid. This results in prey capture times
of even less than 6 ms. However, the long, tubular snout with small diameter
also has its disadvantages, including a limitation on prey size and an
increase in the moment of inertia of the head during dorso-rotation. Our
longterm goal is to investigate the degree to which the extreme
morphological specialization of the feeding system in syngnathids constrains
its functional versatility. One of the limitations that the feeding apparatus may
experience is that of mechanical overloading during the extreme
accelerations of skeletal elements and the production of high suction forces.
Since expansion of the buccal cavity generates a large negative pressure,
this implies that a great amount of mechanical force is exerted onto the head.
We completed a finite element analysis of the skull of Hippocampus reidi to
determine where stress accumulates under the strong pressure generated
during suction feeding. We hypothesized that structural adaptations would be
present in regions of high loading, in order to dissipate stress and avoid
skeletal damage. A thorough histological and morphological study of the
regions and bones that are experiencing the largest mechanical stress during
suction feeding, allowed us to test this hypothesis.
P3.195 LIEBL, Andrea L.*; ALAM, Jennifer L.; MARTIN, Lynn B.; University
of South Florida; [email protected]
Rapid Quantification of the Bactericidal Capacity of Avian Plasma
Ecological immunology is an emerging field of biology, but progress has
been slowed due to the availability of techniques. Bactericidal assays, which
measure the capacity of blood and/or plasma samples to kill microorganisms,
have been used extensively in the past several years because only a single,
small sample of blood and minimal equipment is required to perform the
assay. Our goal in the present study was to improve current techniques by
reducing the amount of processing time, necessary blood/plasma volume,
and the need to culture test samples overnight through the use of
spectrophotometry (using a Nanodrop). Preliminary data indicate that the
bactericidal capacity of house sparrow (Passer domesticus) plasma against
E. coli using our approach is comparable to current methods. Ongoing
studies are i) validating this approach for other microorganisms (e.g.,
gram-positive bacteria and fungi), ii) comparing whole blood versus plasma
capacity, iii) assessing repeatability, and iv) ascertaining the effects of
long-term storage on sample viability.
P3.37 LIN, H.*; TRIMMER, B.A.; Tufts University; [email protected]
Soft dynamics --- ground reaction forces in a crawling caterpillar
Most terrestrial soft bodied animals move by pressing against the substrate
in carefully controlled sequences. However, lepidopteran larvae have
well-developed limbs (the prolegs) that can be used for climbing in complex
branched structures and on a variety of surfaces. The tobacco hornworm,
Manduca sexta is therefore an excellent animal to study how limbed
locomotion in soft-bodied animals compares to that of legged animals with
rigid skeletons. In this study, we devised a method to measure the ground
reaction forces (GRFs) in fifth instar Manduca at all contact points during
crawling. A multi-sensor array was built to match the step pattern of the
caterpillar and to measure the GRF exerted by each proleg with <mN
accuracy. By tracking individual proleg movements a GRF profile could be
determined for each segment. During horizontal crawling different prolegs
were found to have their own characteristic ground contact pattern with
stereotypic crochet protraction. Remarkably, the crochets release their grip
with negligible upward force. Simultaneous measurement of all proleg GRFs
normal to the direction of travel revealed a rhythmic redistribution of body
weight corresponding to the ground thrust during stepping. The work done by
different prolegs could be estimated by following the moving center of mass
and, by integrating the GRF data, we were able to deduce the effective
momentum during various phases of locomotion. Similarly, from GRF loading
rates, we obtained invaluable information about force propagation. These
findings could help to understand how soft-bodied animals exploit internal
dynamics to exert forces on their environment.
P3.143 LIN-YE, A; PANTAZATOS, S; GEDDIS, MS; AMBRON, RT;
GOODMAN, RM*; Columbia University, BMCC-CUNY, Columbia University;
[email protected]
ELECTROMAGNETIC FIELDS PROMOTE REGENERATION FOLLOWING
INJURY: INDUCTION OF INCREASED hsp70 LEVELS AND BINDING OF
INJURY-SPSECIFIC FACTORS IN THE MAPK CASCADE
Electromagnetic fields (EMFs) are used medically to promote tissue repair,
but the molecular pathways by which this occurs are only beginning to be
understood. EMFs are known to up-regulate the heat shock gene HSP70
and to induce elevated levels of hsp70 protein. The activation of HSP70
occurs through the binding of heat shock factor 1 (HSF 1) to a heat shock
element (HSE) in the region of the HSP70 promoter that contains three
nCTCTn consensus sequences. These sequences are distinct from the
sequences involved in thermal response and do not respond to elevated
temperature. In this set of experiments Planaria were transected equidistant
between the head and the tail. Individual head and tail portions were
exposed to a 60 Hertz 80 milliGauss EMF for one hour, 2x a day for 15 days
post-transection. The regenerating heads and tails were photographed and
lengths were measured at 3-day intervals. In some experiments protein
lysates were analyzed for hsp70 levels, doubly phosphorylated (pp)-ERK,
Elk-1 kinase activity, and SRF-SRE binding, using either Western blot or
EMSA. During the initial 3 days post-transection, EMF exposure caused a
significant increase in regeneration for both heads and tails -- more so for
tails. Concurrently, EMF-exposed heads and tails exhibited an elevation in
the level of hsp70 protein, activation of an ERK cascade and an increase in
SRF-SRE binding. Our results indicate that a well-defined EMF promotes
regeneration in Planaria accompanied by an increase in hsp70 levels and the
activation of kinases and transcription factors that are typically associated
with repair mechanisms. These findings provide insight into the clinical
application of EMFs. Support provided by the Robert I. Goodman Fund.
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P1.34 LINDSAY, S.M.; Univ. of Maine, Orono; [email protected]
Ecology of injury in marine soft sediment communities: methyl green
staining improves identification of regenerating spionid polychaetes
Marine infauna such as polychaetes are ecosystem engineers, disturbing
sediments as they feed, defecate, burrow, irrigate and build tubes. These
activities influence fluxes between sediments and the water column,
recruitment and competitive interactions. Factors that change infaunal
activity can thus impact sediment biogeochemistry and benthic communities.
Infauna commonly experience non-lethal loss of body tissue and such injury
has direct and indirect effects on infauna and ecological interactions in
marine sedimentary habitats. Predicting the degree to which injury impacts
soft-sediment communities requires accurate estimates of infaunal injury
rates. Because soft-bodied infauna do not have visible scars after they have
regenerated, knowing whether a seemingly intact individual may have
experienced injury is difficult. For polychaetes, most estimates of injury rates
in the field have been conservative, only counting worms that have obviously
regenerating body parts. In addition, field surveys of injury have tended to be
snap-shots, taken at one site over only short periods of time. Rapid
regeneration in some species can mask injury, especially if sampling
intervals are long. This study evaluated a histological stain, methyl green
(MG), as a method to improve identification of recently injured but apparently
intact spionid polychaetes. Visual and MG methods for identifying
regenerating worms were compared in several species of spionid
polychaetes collected from False Bay, WA and Lowes Cove, ME. Traditional
visual inspection underestimated the frequency of injury/regeneration by
approximately 5-20% depending on the species. The utility and limitations of
MG staining as an assay for infaunal injury will be discussed.
P1.69 LINVILLE, B.J.*; STEWART, J.R.; ECAY, T.W.; HERBERT, J.F.;
THOMPSON, M.B.; East TN State Univ, Univ Sydney;
[email protected]
Placental Calcium Provision in a Lizard with Prolonged Oviductal Egg
Retention
An hypothesis to explain the evolution of viviparity and placentation in
reptiles predicts that reduction in shell thickness and the advent of
placentotrophy occur coincident with prolonged oviductal egg retention.
Saiphos equalis is an Australian scincid lizard with a reproductive mode that
is uncommon for squamates: 1) eggs are retained in the oviduct until late
developmental stages, and 2) the embryonic stage at oviposition varies
geographically. We studied calcium mobilization by embryos in two
populations with different egg retention patterns to determine the relationship
between shell thickness, pattern of nutritional provision of calcium and
embryonic stage at oviposition. Females from one population oviposit eggs
that hatch in 6 days, while eggs from a second population hatch within 2
days. Embryos of both populations mobilized calcium from yolk, shell and
placenta. Yolk provided the highest proportion of calcium to hatchlings.
Shells of the population with a shorter period of egg retention had twice the
calcium content of the second population and embryonic uptake of shell
calcium was higher in these eggs. Placental transfer accounted for more
calcium in hatchlings than extraction from the shell in both populations.
Pattern of calcium provision is similar in these two populations, yet they vary
in relative contribution of each source to hatchling nutrition. Our results
demonstrate that shell calcium content is correlated inversely with the length
of egg retention in S. equalis. Our findings also support the hypothesis that
the evolution of placentotrophy occurs concurrently with prolonged oviductal
egg retention. Supported by a grant from the NSF (IOB-0615695).
P3.72 LOCKHART, L.*; BONIER, F.; MUNRO, H.; MOORE, I.;
ROBERTSON, R.; Queen's University, Kingston ON, Virginia Tech;
[email protected]
The relationship between parasitemia and resource allocation in
Tachycineta bicolor
Within-individual trade-offs in resource allocation exist because of constraints
and limitations on those resources. Because of these constraints and
limitations, an individual may be forced to trade off between investment in
immune system function, body condition, and response to environmental
challenges, for example. However, we do not know how all of these functions
are linked and what mediates the trade-offs that occur between them.
Addressing this question will provide insight into how resources are
allocated, particularly when an organism is confronted with environmental
challenges. We examined the relationships between endoparasitemia in a
free-ranging population of tree swallows (Tachycineta bicolor) and three
measures of their resource allocation: white blood cell count, body condition,
and corticosteroid levels. Results show that tree swallows with high
parasitemia levels also had low body condition, a low heterophil: lymphocyte
ratio, and a high corticosteroid level. These results suggest that in order to
fight off parasite infection, tree swallows directed more energy toward their
immune response and less energy toward maintaining body condition.
Corticosteroid hormones, often considered an accurate measure of response
to environmental stress in animals and known to play a role in immune
responses, were elevated in birds with high parasitemia, and thus may play a
role in mediating the trade-offs we observed. Our correlative findings provide
evidence of the trade-offs that occur in organisms under stressful conditions.
Further study is needed to determine the causal role that corticosteroids
might play in mediating resource allocation.
P1.28 LOGAN, Michael L*; MONTGOMERY, Chad E; BOBACK, Scott M;
REED, Robert N; CAMPBELL, Jonathan A; University of Texas at Arlington,
Truman State University, Dickinson College, United States Geological
Survey; [email protected]
The comparative ecology of Norops lemurinus (Sauria; Polychrotidae)
on the islands of Cayo Menor and Cayo Mayor of the Cayos Cochinos
archipelago of Honduras.
In Honduras, Norops lemurinus (Sauria; Polychrotidae) is distributed along
the Atlantic versant of the mainland and on the Caribbean island system
consisting of the Bay Islands and Cayos Cochinos archipelagos. In the
Cayos Cochinos, N. lemurinus occurs on two islands, Cayo Menor and Cayo
Mayor. The abiotic and biotic environment of these islands differs noticeably
from the mainland, while the environments of each island differ from each
other to a lesser degree. To examine the potential morphological, ecological,
and physiological correlates of these differences in environment, we sampled
lizards from both islands, measuring 15 morphometric variables, 13 habitat
variables, and field active body temperatures. Additionally, we measured
upper thermal tolerance and evaporative water loss for the Cayo Menor
population, and compared our results to previously published data for
mainland populations. After correcting for snout-to-vent-length, Cayo Menor
males had greater mass and dewlap diameter, while females did not differ in
any morphological character examined. When males and females were
pooled, perch width and temperature at perch site were greater on Cayo
Mayor. Additionally, lizards on Cayo Menor were found at greater distances
from open environments (areas with breaks in canopy cover). Observed
differences in morphology, physiology, and habitat use can perhaps be
explained by differences in temperature and rainfall regimes, habitat
availability, and niche relationships with potential competitors.
e264
P3.74 LONDRAVILLE, R.L.*; HEMLEPP, L; COPELAND, C;
SCARBOROUGH, J; University of Akron; [email protected]
Response of leptin I and II to cold acclimation in carp.
Leptin is a small (16 kDa) peptide hormone that influences fat deposition,
metabolic rate, satiety, reproduction, angiogenesis, bone density and
immune function in mammals. Its study in basal vertebrates has been
hampered by difficulty cloning the cDNA; however recent labs have had
success for fish, including Fugu (Kurokawa and Suzuki, Peptides 26:745,
2005) and Cyprinus carpio (Huising et al., Endocrin. 147: 5786, 2006). Carp
are the only vertebrates reported to date that express multiple isoforms of
leptin. As temperate-zone fishes typically accumulate body lipid as they
acclimate to temperatures, we acclimated carp to 5C and 25C for 8 weeks to
measure the response of each leptin isoform to leptin exposure.
Semiquantitative PCR indicates that cold exposure significantly increases
mRNA expression of both leptin isoforms. Currently we are confirming these
results with quantitative (real-time) PCR. These data indicate that the leptin
signal in ectotherms remains coupled to adipose stores (both increase with
cold exposure) as opposed to endotherms, where adipose stores increase
while leptin decreases.
P2.24 LONGORIA, A*; AGUIERRE, P; FREDENSBORG, BL; University of
Texas_Pan American; [email protected]
Living on the edge: A field study on the effect of salinity and parasitism
on an intertidal gastropod
Physiological stress and parasitism are both important stressors affecting the
abundance, diversity and composition of intertidal animal communities.
However, rarely have the two stressors been studied in concert. This study
investigated the effect of a naturally occurring rapid decrease in salinity on
the density of plicate horn snails, Cerithidea pliculosa, and the prevalence
(%) of larval trematodes (flukes) using the snails as hosts. Random
collections of C. pliculosa were conducted on two separate occasions on
three intertidal flats in Laguna Madre, South Texas. The density of snails was
determined and >100 snails were dissected per site to determine the
infection status of the snails. The first collection was conducted five days
prior to the arrival of a category two hurricane (Hurricane Dolly). The second
sampling event took place three weeks later. A drop in salinity was recorded
in the study area due to substantial rainfall during the storm. No difference in
the density of snails was observed for any of the three sites indicating that C.
pliculosa is tolerant to variations in salinity. In one of the three sites, the
prevalence of infection by larval trematodes decreased significantly(P =
0.012)suggesting that infected snails disproportionately were lost from the
population. No difference in prevalence could be detected for any of the two
other sites (P= 0.10 and P = 0.99),but the proportions of trematode species
significantly differed between the two sampling events for all three snail
populations (p <0.025). In conclusion, occasional events of stressful
conditions can influence host-parasite interactions but the outcome seems to
be species specific. More studies are needed on the effect of physiological
stress on host-parasite interactions.
P1.93 LOUDON, S. J.*; ALDWORTH, Z. N.; DANIEL, T. L.; University of
Washington; [email protected]
Perturbing flight paths in Lepidoptera by inducing abdominal flexion
Insects use rapid body rotations during flight control. These rotations are
generally considered to be initiated by the wings. Insects can also use the
movement of other body parts, such as the head, legs or abdomen, to
influence their flight path. A recent study in the crepuscular hawkmoth,
Manduca sexta, has suggested that abdominal movements are used during
tracking flight to cancel pitching and yawing motions initiated by the wings.
However, it is unknown to what extent abdominal movements themselves
can be used to initiate changes in the flight path. To address this issue we
elicited abdominal movement in Manduca through electrical stimulation
during loosely tethered flight in order to determine the extent of association
between abdominal movement and changes in flight trajectory. We used
multiple high-speed cameras to film the animals flight in a closed chamber
under low-light conditions. Stimulation current was delivered using tungsten
electrodes inserted through the ventral cuticle of the thorax. Four stereotyped
body points were digitized from the flight sequences, and used to extract
3-dimensional flight parameters such as yaw and pitch, as well as the
dorsal-ventral and lateral flexion rates of the abdomen. We then used
correlation analysis to determine the relationship between the abdominal
movement and the observed changes to the flight path. We consistently
found abdominal movements and changes in flight posture following
stimulation, and flexion data were correlated with the attitude changes at
delays of between 500-750 ms. These results demonstrate that abdominal
movements can be used in insect flight control.
P3.159 LOUNSBERRY, Zachary*; SOARES, Daphne; University of
Maryland, University of maryland; [email protected]
Female choice of Betta splendens using a socially complex paradigm
What are the parameters used by females when choosing a mate? I chose to
study the behavior of the siamese fighting fish (Betta splendens) to examine
the underlying mechanisms that dictate female choice. Males of this species
are known for their elaborated displays and violent fights, presumably
investing their resources to influence mating success. Former studies have
tested parameters such as fin length, body size, coloration, visual displays,
and nest size. While it is likely a combination of these characteristics that
ultimately causes the female to choose a mate, it has been shown that a
female that eavesdrops on a fight between two males will almost certainly
choose the winner over the loser. However, it is still unknown what other
social parameters will influence B. splendens females, and here we ask
whether familiarity is a factor. Is a female more apt to choose a male that she
has lived with in a larger social group or one she has never seen before?
Moreover, how does the importance of familiarity compare to the importance
of fighting outcome? To help answer these questions, females from two
socially raised clutches of B. splendens were given a choice between the
males from their respective clutches or a completely novel male. The results
strongly suggest a preference for an unknown male. This preference is
checked against the importance of eavesdropping and other possible traits
that influence female mate choices.
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P2.168 LUTTERSCHMIDT, D.I.*; WILCZYNSKI, W.; Georgia State
University, Atlanta; [email protected]
Melatonin alters arginine vasotocin immunoreactivity in green treefrogs
(Hyla cinerea).
The arginine vasopressin/vasotocin (AVP/AVT) system plays an important
role in regulating sexual behavior, including mediating responses to
sociosexual stimuli. Although reproduction is regulated seasonally in many
animals, few studies have investigated whether seasonal changes in
reproductive behavior are concurrent with seasonal changes in AVP/AVT.
Previous work in our laboratory demonstrated a seasonal increase in
AVT-immunoreactive cell number in green treefrogs (Hyla cinerea). In the
present study, we investigated whether melatonin mediates this seasonal
change in AVT immunoreactivity. Treatment of green treefrogs with
melatonin-filled silastic capsule implants for 4 weeks significantly altered AVT
immunoreactivity, although these differences depended significantly upon
sex. In male treefrogs melatonin treatment significantly increased
AVT-immunoreactive cell number in the suprachiasmatic nucleus and caudal
hypothalamus, while in female frogs melatonin did not significantly influence
AVT immunoreactivity. Similar to previous studies, we also observed a
significant sex difference in the number of AVT-immunoreactive cells in frogs
treated with a blank implant, with female frogs having more immunoreactive
cells in the suprachiasmatic nucleus and caudal hypothalamus than male
frogs. These results indicate that the AVP/AVT system is an important target
for melatonin in facilitating seasonal changes in reproductive physiology and
behavior.
P2.62 MACESIC, L.J.*; SUMMERS, A.P.; KAJIURA, S.M.; Florida Atlantic
Univ., Univ. of California, Irvine, Florida Atlantic Univ. ; [email protected]
Flexural stiffness and composition of the propterygia of punting and
non-punting batoids.
Benthic batoids perform a mode of locomotion termed punting, during which
the pelvic fins are depressed into the substrate and then extended caudally
to propel the body forward, while keeping the rest of the body still. Skates,
which possess muscular and skeletal specializations for punting, and the
lesser electric ray, Narcine brasiliensis, exhibit this true punting pattern.
However, some benthic batoids, such as the Atlantic stingray, Dasyatis
sabina, and the yellow-spotted stingray, Urobatis jamaicensis, have
demonstrated an augmented punt, which also includes pectoral fin
movements. In this study, our goal was to determine if these differing
kinematic patterns relate to structural and compositional differences within
the main punting skeletal element, the pelvic propterygium. In addition to the
species listed above, the pelagic stingray, Pteroplatytrygon violacea, was
also tested, as its life history suggests that the pelvic fins are not used for
this benthic locomotion. We performed morphometric analyses, three-point
bending tests, and compositional analyses. Our results show that the skate
possesses propterygia with significantly higher second moments of area
when compared to the other species tested. Propterygia of the true punters
have approximately 80% greater flexural stiffness than the augmented
punters (p<0.05). Moreover, propterygia of the augmented punters have
almost twice the flexural stiffness compared to the non-punting pelagic
stingray (p<0.05). For all species, we found that neither water nor mineral
content are good predictors of flexural stiffness. This study demonstrates that
the flexural stiffness of propterygia in benthic batoids may have evolved in
order to resist the bending forces experienced during punting.
P3.208 MACMILLAN, Heath/A*; SINCLAIR, Brent/J; University of Western
Ontario; [email protected]
Membrane remodeling, glucose and Drosophila melanogaster cold
tolerance: A test of chilling injury protection hypotheses.
Insect cold tolerance varies at both the population and species levels.
Carbohydrate cryoprotectants and membrane remodelling are two main
mechanisms hypothesised to increase chilling tolerance in Drosophila
melanogaster, as part of both long-term (ie: evolutionary) change and rapid
cold-hardening (RCH), which can take place in minutes to hours. We used
cold-selected lines of D. melanogaster with and without a pre-exposure that
induces RCH to test three hypotheses: 1) that increased cold tolerance
would be associated with increased free glucose; 2) that increased cold
tolerance would be associated with desaturation of membrane phospholipid
fatty acids and 3) that increased cold tolerance would be associated with a
change in phospholipid head group composition. We used colourimetric
assays to measure free glucose and a combination of thin layer
chromatography-flame ionization detection and gas chromatography to
measure membrane composition. We observed a consistent decrease in free
glucose with RCH, and no relationship between free glucose and basal cold
tolerance. Also, phospholipid head group ratios and fatty acid composition
showed no change following an RCH treatment. Thus, we conclude that
changes in free glucose and membrane composition are unlikely to be
significant determinants of variation in cold tolerance of D. melanogaster.
P2.73 MAIA, A.; Univ. of Rhode Island, Kigston; [email protected]
Escape responses early in life: are young of the year spiny dogfish
doing well?
Most species encounter greater predatory pressure early in life, before they
are able to achieve adulthood. To evade predators, the most common
behavior an animal will use is an escape response. In this study, escape
behavior is investigated in young of the year spiny dogfish, Squalus
acanthias. Escape responses were elicited by gentle nudging of the tail
region to represent a possible predatory event in seven individuals. The
results obtained were compared with published data on adult spiny dogfish
escape responses. Similar to adult spiny dogfish, the young of the year were
shown to elicit C-type escape responses, characterized by a bend into a C
shape in stage 1, followed by a return to a natural position in stage 2.
Duration, center of mass speed, snout speed, turning rate, and turning angle
were quantified for stages 1 and 2. Young of the year spiny dogfish do not
show a bimodal distribution in response type, unlike that reported for spiny
dogfish adults where two types of response were found, slow and fast. Size
corrected maximum velocity of the escape response is faster in the young of
the year dogfish, with absolute values close to the values reported at the
lower end of the spectrum of adult dogfish. Mean angular velocities in young
of the year dogfish are similar to the faster values reported for adults, and
maximum angular velocity was faster than in adults. This is consistent with
previous reports on greater maneuverability in smaller sized fish. In addition,
angular velocity and stage 1 duration are inversely correlated and can be
described by a linear regression. Plots of turning rate over time in young of
the year dogfish are very similar to the faster escape responses reported for
adults. Overall, young of the year spiny dogfish are competent in fast starts
and do so in a similar fashion as the adults.
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P2.55 MARKLEY, J.S.*; GOLLER, F.; CARRIER, D.R.; Univ. of Utah, Salt
Lake; [email protected]
Estimating the cost of ventilation in zebra finches by increasing
mechanical work
The cost of ventilation may be high in birds due to the large mass of the
ventilatory system, which must be moved with every breath. To measure this
cost we developed a mechanical method to increase the work of breathing in
small, readily available zebra finches. Birds were surgically outfitted with
velcro sutured to the distal end of the sternum, around the sternal ribs, and to
the skin covering the synsacrum (back). A custom built mask with a screen
pneumotach was used to measure ventilation, and oxygen consumption
(Vo2) was measured via flow-through respirometry. Weights of approximately
7, 9 and 13% of body mass were added alternately to the sternum and back.
The mass of the sternum and associated flight muscles in zebra finches is
14% of body mass. Mean oxygen consumption values for 3 minute periods
were used to calculate minute ventilation, frequency, Vo2. Preliminary results
indicate that changing the location of these masses from the back to the
sternum produced no change in Vo2. Birds may have been forced to change
their mode of breathing or their perching posture when faced with these
loads. The actual cost of ventilation remains equivocal, nevertheless, this
result potentially reveals plasticity in ventilatory mechanics of passerines,
which allows birds to mitigate the cost of added sternal mass.
P3.54 MARSH, Richard L.*; HANSEN, Eric; WATSON, Rebecca; PROPERT,
Matthew W.G.; Northeastern University; [email protected]
Net joint work as a function of speed in a small running bird, the
chukar.
Little information is available on the mechanical work done at individual joints
in small running animals. We calculated the net work done at the joints of
chukars running over a force plate at approximately constant speeds ranging
from 0.27 to 2.7 m/s. Using simultaneous high-speed video to measure joint
kinematics and measures of segment properties, we calculated net joint work
using 2-D inverse dynamics. As expected for constant-speed runs the
positive and negative work summed across all joints were approximately
equal. However, the individual joints showed large differences in the amount
and sign of the work done. Positive joint work showed the highest values at
the hip and the ankle, but, whereas the ankle showed an almost equal
amount of negative work, very little negative work was done at the hip.
Negative work predominates to varying degrees at the
tarsometatarsal-phalangeal, and inter-phalangeal joints. Although, these
values cannot be interpreted directly in terms of muscle work, they provide
valuable guidelines regarding which muscles likely provide positive work and
which are involved energy storage, and braking. Supported by NIH AR47337
and NSF IOB-0542795.
P1.51 MARSHALL, C.D.*; MOSS, A.L.; GUZMAN, A.; Texas A and M
University at Galveston; [email protected]
Loggerhead Sea Turtle (Caretta caretta) Feeding on Mackerel-Baited
Longline Hooks
The large longline fishery bycatch of loggerhead & leatherback sea turtles is
a serious concern for both managers & conservationists. US longliners have
switched from a J hook to a circle hook, & switched bait from squid to
mackerel; both changes are thought to decrease bycatch. However, few
studies have investigated loggerhead feeding in detail. Therefore, we
conducted a kinematic study using 6 captive loggerhead turtles feeding on
barb-less, mackerel-baited longline hooks (18-0 circle vs. J-25) to
characterize loggerhead feeding on mackerel. Kinematic variables for
loggerheads feeding on mackerel from 18-0 circle hooks were: max gape =
6.7 cm +/- 1.22, time to max gape = 798 ms +/- 379.4, max gape angle =
44.6+/- 9.84, max hyoid depression = 1.4 cm 0.60, time to max hyoid
depression = 1002 ms +/- 396.5, open gape angle velocity = 517/s +/- 156.7,
closing gape angle velocity = 741/s +/- 203.7, & gape cycle = 1030 ms +/412.7. Kinematic variables for loggerheads feeding from J-25 hooks were:
max gape = 7.2 cm 1.2, time to max gape = 896 ms +/- 524.2, max gape
angle = 47.4 +/- 1.03, max hyoid depression = 1.53 cm +/- 0.71, time to max
hyoid depression = 927 ms +/- 349.7, open gape angle velocity = 516/s +/190.6, closing gape angle velocity = 999/s +/- 295.5, & gape cycle = 937 ms
+/- 434.0. No significant differences were found between hook type, with the
exception of max closing gape angle velocity, which was faster when feeding
on the 18-0 circle hook (P<0.01). These data support a recent study using
squid baited circle & J hooks, which suggested that loggerhead feeding
kinematics were conserved regardless of hook type. However, in this study it
was clear that turtles were feeding further from the hook compared to squid
baited hooks.
P2.90 MARSHALL, K.E.*; SINCLAIR, B.J.; University of Western Ontario;
[email protected]
The sublethal effects of multiple acute cold exposure: lessons from
Drosophila
Changes in snow cover and temperature with projected climate change will
influence not only the mean temperatures that overwintering insects are
exposed to, but also the frequency of freeze-thaw cycles. However, the
majority of insect cold tolerance studies have focused on the effects of a
single cold exposure, and the consequences of multiple cold exposure in
insects have remained poorly elucidated. Two competing hypotheses are
proposed: either chill injury is cumulative with increasing cold exposure
regardless of intervals between exposures, or individuals are able to repair
damage incurred during exposure allowing greater survival with repeated
versus sustained cold exposure. We employed a Drosophila model system to
gain a better understanding of the impacts of multiple cold exposure on
metabolic fuels and fecundity. Adult virgin female flies were exposed to either
a sustained (single ten hour) or multiple (five exposures, two hours each
separated by 24 h) cold treatment at -0.5 degrees Celsius. Controls included
treatments that examined the interaction between age and cold tolerance.
Treated flies were assayed for total lipid, protein, and carbohydrate content.
Total male and female offspring from treated females were also counted,
allowing examination of sex ratio, fecundity, generation time, and intrinsic
rate of increase. Initial results support the hypothesis that multiple cold is
less deleterious than sustained cold.
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P2.131 MARSHALL, S.L.*; WEIGAND, K.L.; DEAROLF, J.L.; Hendrix
College, Conway, AR; [email protected]
Influence of betamethasone on the fast-twitch fibers of the external
abdominal oblique in fetal guinea pigs (Cavia porcellus)
Glucocorticoid steroids are used to accelerate the development of various
organs in fetuses before premature delivery. In the present study, the
possible negative ramifications of the use of betamethasone, a
glucocorticoid, on the expiratory external abdominal oblique muscle were
considered. We hypothesize that exposure to betamethasone will result in a
significant amount of muscle atrophy and significant decrease in the
percentage of fast-twitch fibers in the external abdominal oblique. To test
these hypotheses, pregnant guinea pigs were injected with betamethasone
(0.5 mg/kg) or sterile water at 65%, 75%, and 85% gestation. Samples of the
external abdominal oblique were then collected from all fetuses, cut using a
cryostat, and stained for myosin ATPase activity. Images of the stained
muscle sections were taken and fiber percentages were calculated. Scion
Image was used to measure fiber diameter as well. The external abdominal
oblique aids in a fetus ability to exhale carbon dioxide. In periods of stress,
the fast-twitch fibers are recruited to exhale at a faster pace than normal
conditions. A decrease in number or atrophy of the fast-twitch fibers would
impair this muscles ability to contract with the same speed as a normal
non-treated muscle. These side effects would hinder a preterm infants ability
to cope with periods of respiratory distress. This inability to adapt could prove
damaging or life threatening to the infant.
P3.6 MARSHALL, H*; BERNAL, D; University of Massachusetts Dartmouth;
[email protected]
Comparative Metabolic Biochemistry Of Shark Myocardial Tissue
Work on lamnid sharks (Family Lamnidae) has revealed their ability to
undergo broad high-latitude migrations and rapid and repeated sojourns into
depths below the thermocline. Both scenarios expose these fishes to cold
temperatures. Lamnids have the ability to maintain their swimming muscles
at temperatures above ambient (regional endothermy), and this quality may
allow these sharks to sustain elevated muscle metabolic biochemical
capacities when exposed to cold water. However, the lamnid heart does not
benefit from regional endothermy and all myocardial tissues are at thermal
equilibrium with ambient temperatures. Proper cardiac function is essential
for providing lamnids with adequate supplies of oxygenated blood for
maintained swimming muscle function. Thus, a heart that is exposed to
prolonged cold or rapidly fluctuating ambient temperatures should be
capable of maintaining elevated metabolic biochemical capabilities. The
objective of this study was to compare the activities of citrate synthase (CS)
and lactate dehydrogenase (LDH) in the myocardial tissue of lamnid and
non-lamnid sharks at various temperatures in order to determine how
enzyme activities are affected. Analysis shows that CS activity is significantly
higher at 20C for lamnid sharks (24.2+/-3.4 IU g-1) relative to non-lamnids
(12.6+/-1.5 IU g -1 ). LDH activity is also significantly higher in lamnids
(169.8+/-52.2 IU g-1) relative to non-lamnids (109.6+/-19.6 IU g-1). There was
no significant difference in the thermal rate coefficients (Q 10 ) at 10-30C
between lamnids (1.58+/-0.4) and non-lamnids (1.56+/-0.2) for CS. The Q10
values at 10-30C for LDH also showed no differences between lamnids
(1.71+/-0.3) and non-lamnids (2.22+/-0.4). It appears that lamnids have
higher cardiac enzyme activities than non-lamnids, but are similarly affected
by temperature changes.
P1.154 MARTIN, James, T.*; DEFUR, Peter, L.; Virginia Commonwealth
Univ; [email protected]
Responses of Blue Crabs to Hypoxia in Fresh Water
Previous work demonstrated that blue crabs (Callinectes sapidus) in saline
waters respond to long term hypoxia by increasing hemocyanin
concentration and oxygen transport properties. Additionally, researchers
reported that under field conditions and lab simulations, hypoxia is
accompanied by hypercapnia and low pH, affecting hemolymph pH. The
present research examined responses of blue crabs to long term
hypercapnic hypoxia in freshwater at 23C. Hypoxic conditions (50-60 mmHg
O2) were induced by allowing the crabs to consume oxygen supply, resulting
in a hypercapnic induced decrease in pH from 7.88 to 7.18. Post-branchial
hemolymph oxygen and pH were measured in normoxia, after 24 hours of
hypoxia and several days later. Within 24 hours, postbranchial hemolymph
oxygen declined 46% to 79%, but post-branchial pH changes varied from
-0.167 to +0.171 The initial responses to hypoxia demonstrates that blue
crabs prevent extreme postbranchial hemolymph pH changes under acidic
stress as well as maintain postbranchial oxygen tension. Despite the
variation in postbranchial hemolymph among individual crabs, 86% mortality
occurred during three days of hypoxia. The high mortality rate suggests the
blue crabs are not able to survive the multiple stress of hypoxia/hypercapnia
along with the stress of living in freshwater. It is not clear if the elevated
mortality results from a failure of oxygen transport, acid-base balance or ion
regulation. Supported by a Rice Center Graduate Student support grant to
JTM.
P1.30 MASONJONES, H.D.*; ROSE, E.; University of Tampa;
[email protected]
Reproductive demographics of syngnathid fishes inhabiting a
human-altered landscape
Syngnathid fishes (pipefish and seahorses) are distinguished by their
unusual brooding and mating systems. Due to their low mobility and high site
fidelity, human alteration of the landscape may have dramatic impacts on
their biology. This two year study investigated seasonal reproductive patterns
of two syngnathid species, the gulf pipefish (Syngnathus scovelli) and the
dwarf seahorse (Hippocampus zosterae) using a modified mark-recapture
technique. Every 2-4 weeks, fish were collected via pushnet from 3 adjacent
sites in Tampa Bay (FL), varying in their distance to open water within the
system. This location was selected because of a nearby marina/housing
construction project, which began six months into our study. Fish were
marked, photographed, and released the same day to their collection sites.
Our results indicate a large, flexible population with data for 5300 individuals.
Reproductive demographics varied markedly across season in both S.
scovelli and H. zosterae, with sex ratio cycling predictably in S. scovelli, but
fluctuating dramatically in H. zosterae with season. Other sexual variables
analyzed included habitat use by males and females (H. zosterae and S.
scovelli), degree of sexual ornamentation in females (S. scovelli), and
frequency of partial pregnancies in males (S. scovelli), all of which were
found to vary across season. These results suggest the potential for
environmental effects on the sexual selection landscape that may affect the
availability of mates across season. Our results also indicate that population
size and sexual ornamentation decreased and the frequency of partial male
pregnancies increased across the study period, suggesting the possibility
that degradation of environmental quality due to construction could have also
impacted reproduction.
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P1.162 MATOZEL, Michelle; MARKS, Chris*; MOORE, Francisco/B.-G.;
BAGATTO, Brian; University of Akron, Ohio; [email protected]
Effects of Hypoxia on the Development of the Digestive System and
Metabolism of the Zebrafish
Hypoxia slows growth and development, and limits the survival of many fish
species. Many studies in fish have shown a significant decrease in metabolic
rate when exposed to hypoxia; a mechanism which permits fish to survive
but may come at a cost. Whether a cost or benefit, data show that many fish
species including zebrafish are smaller to their normoxic counterparts when
reared in hypoxic water. Smaller body size could be directly related to the
decrease in the metabolic rate, which may or may not be related to a
decreased amount of food consumption. The development of the digestive
system itself may also be delayed by hypoxia. Decreased blood flow to the
gut, could easily lower caloric assimilation. The effects of hypoxia on the
digestive system were studied in larval and juvenile zebrafish. Yolk volume,
blood flow to yolk, gut and cloacal area, and heart rate were compared
between normoxic and hypoxic zebrafish larvae. The larval experiments
show that there is a lag in development of the digestive system and decrease
in blood flow in hypoxic zebrafish. In juvenile zebrafish, metabolic rates were
lower in hypoxic zebrafish. It is yet undetermined if food consumption and
assimilation differ between the two groups.
P3.98 MATSON, K.D.; CARLTON, E.D.*; HOWARD, J.L.; HUDAK, C.A.;
LYNN, S.E.; MAUCK, R.A.; University of Groningen, Kenyon College, The
College of Wooster; [email protected]
Effects of an experimental immune enhancement, rather than an
immune challenge, in a wild bird.
Experimental manipulations of the immune systems of wild birds most
commonly take the shape of immune challenges. These challenges are
intended to induce immune responses and to force tradeoffs among limited
resources (e.g. energy). Instead of challenging birds, however, we
endeavored to enhance immune function in nestling Eastern bluebirds (Sialia
sialis). Immune enhancement was attempted by orally supplementing young
birds with a lysozyme solution throughout the nestling period. Lysozyme, a
natural antibacterial protein, functions by hydrolyzing cell-wall peptidoglycan,
making Gram-positive bacteria particularly susceptible to its effects. This
protein, produced by many animals, has been identified in avian blood and
egg albumin. Furthermore, lysozyme concentrations are known to vary
among individuals (in adults, nestlings, and eggs). We hypothesized that by
providing nestlings with extra lysozyme we could increase this line of
immunological defense without increasing the costs associated with its
production. Furthermore, we hypothesized that the relative importance of
lysozyme to nestling bluebird physiology will be reflected in concomitant
effects on chick immune function, growth and development, and parental
care. We collected and analyzed plasma samples to establish the degree to
which lysozyme treatment impacts indices of immune function, we recorded
body and feather measurements to determine the effects of treatment on
nestling growth and development, and we quantified feeding rates to identify
any compensatory adjustments in parental behavior in response to nestling
condition. Preliminary results suggest immune enhancement affects some
aspects of nestling physiology, while seemingly not others.
P3.175 MAZZILLO, Maria J.*; KEMPF, Stephen C.; Auburn University;
[email protected]
Mucilage Antigenicity and Composition in Different Zooxanthella
Strains
Zooxanthellae (genus: Symbiodinium) are brown, unicellular algae that
reside intracellularly in most cnidarians and comprise at least 8 clades, each
consisting of several strains. In this mutualism the endosymbiotic algae are
within a symbiosome membrane (host and symbiont-derived) and donate
photosynthetic products to their host in exchange for shelter and nutrients.
Symbiodinium produce mucilage that surrounds the cells while within the
symbiosome or as free-living algae. The specificity of this association is
beginning to be understood; however, the importance of mucilage production
has not been examined. The symbiosome membrane is the area of interface
in this symbiosis and is presumably important in recognition and transfer of
nutrients. Cultured Symbiodinium were labeled with a previously developed
primary antibody that binds to symbiont mucilage (PC3) and visualized with a
fluorescent secondary antibody on a confocal microscope to identify labeling
in different clades and strains. Mucilage contained PC3 antigen in cultured
zooxanthellae from clades A and B from a variety of hosts, except
Montastrea faveolata which did not label. The algae from clades C, D, and H
did not label (including those from M. faveolata). Biochemical analyses of the
mucilage show 1.09 g/L of carbohydrate and 36.7 g/L of protein. Using a 13C
source to assay photosynthetic carbon incorporation in the mucilage of dark
and light incubated, cultured algae shows incorporation of 6.8%, indicating
photosynthetically fixed carbon is a significant component. These data
suggest that the mucilage may play a role in both specificity between host
and symbiont and in the translocation of carbon to the host.
P1.18 MCCLARY, M.*; BENTIVEGNA, C.S.; Fairleigh Dickinson Univ., Seton
Hall Univ.; [email protected]
Effects of a clay cap on contaminants in water, sediments and
macroinvertebrates of Kearny Marsh
Sediments contaminated by organic compounds, heavy metals, and other
potentially toxic chemicals have accumulated in many of the worlds
deepwater and wetland environments. This project investigated a new in situ
capping technology that could be used to remediate and/or manage
contaminated sediments. AquaBlokTM (AB) is a patented,
composite-aggregate technology comprised of a solid core, an outer layer of
clay material, and polymers. When placed in water and over sediment, AB
hydrates forming a layer between contaminants in sediment and the
overlying water. AB was placed in a marsh between July 25th and August 3rd
of 2005. For water quality in May of 2006 the controls were lowest in
temperature, DO, pH, and ORP. In August of 2006 the controls were highest
in temperature and duplicate plots were split between being the highest and
lowest in DO, pH, and ORP. In October of 2006 a control was almost always
lower in all parameters and AB was highest in all water quality parameters. In
November of 2006 control temperatures, DO, and pH were the lowest
whereas depth was highest. Total suspended solids were always similar in
all plots as was number of benthic macroinvertebrates from cores which
were low. The numbers were higher on the Hester-Dendys. For
contaminants of concern (COC) in water, Cd was highest in the AB plots. Fe
was highest in AB, and Pb was lowest in control plots and highest in the AB
plots. Organic contaminants were lowest and highest in AB. COC in
Hester-Dendy macroinvertebrates was similar in all plots. For COC in the
sediment, metals and organic contaminants were highest in the control plots.
These results suggest that AB is more effective in the removal of COC in
sediment than it is in decreasing TSS, increasing diversity and abundance of
macroinvertebrates, and removing Cd, Fe, Pb, and organic contaminants
from the water column.
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P1.32 MCCLINTOCK, James B.*; ANGUS, Robert A.; MCDONALD ,
Michelle R.; AMSLER, Charles D.; Univ. of Alabama at Birmingham;
[email protected]
Ocean acidification and calcified Antarctic seafloor macroorganisms:
The perfect storm
An important consequence of anthropogenic production of atmospheric CO2
is the acidification of the worlds oceans. Antarctic seas are perhaps the most
vulnerable anywhere due to: 1) an inverse relationship between dissolution
rates of calcium carbonate and temperature, and 2) a preponderance of
generally weakly calcified macroorganisms due to either the high cost of
calcium carbonate production at low temperature and/or a lack of
evolutionary selection for robust calcification due to the absence of
shell-crushing invertebrate (crabs) or heavily jawed fish predators. Employing
shells of the common antarctic bivalves Laternula elliptica and Yoldia eightsi,
the limpet Nacella concinna (with and without an encrusting coralline alga),
as well as the brachiopod Liothyrella uva, we measured rates of dissolution
under conditions of ambient (pH 8.2) and acidified (pH 7.4) seawater (current
models predict pH 7.4 in the world's oceans by the year 2200). Shells were
cut lengthwise, weighed, and placed into 1-liter glass beakers with seawater
that was aerated with different concentrations of C02 so as to regulate pH.
Within 14 days shells in acidified sea water had lost their luster. After 5
weeks the shells and thallus of the coralline alga had suffered significant
dissolution when compared to controls. Moroever, one of the shells of the
bivalve L. elliptica in acidified seawater became so fragile it fragmented into
multiple pieces. Our findings indicate that antarctic calcified seafloor
macroorganisms, and the communities they comprise, are likely to be the
first to experience the cascading impacts of ocean acidification. Supported
by NSF OPP#0442769 to JBM and CDA.
P3.209 MCCORKLE, A.M.*; LOOMIS, S.H.; Connecticut College;
[email protected]
Natural ice nucleating bacteria increase the freezing tolerance of the
intertidal bivalveGeukensia demissa
Instead of avoiding freezing, freeze tolerant invertebrates actively initiate
controlled ice nucleation at relatively high sub-zero temperatures in
extracellular compartments. Most produce proteinaceous ice-nucleators in
their hemolymph, however the intertidal bivalve mollusc Geukensia demissa
lacks this ability and instead utilizes a natural ice-nucleation active (INA)
bacterium (Pseudomonas fulva) to induce crystallization in the pallial fluid. In
this study, two additional INA bacteria strains were isolated from the palial
fluid of Geukensia: Psychrobacter sp. and Shewanella sp. The ice-nucleation
activity of both strains was characterized and Psychrobacter was found to
consistently induce nucleation at temperatures 1-3C higher than Shewanella.
The presence of Psychrobacter in the palial fluid of warm acclimatized
Geukensia significantly decreased the LT50 from -12.5C to -15.0C, close to
LT 5 0 of winter acclimatized specimens (-16.5C). Gills from summer
acclimatized Geukensia, had 12% more cell damage than gills without added
bacteria when frozen at -13.5C. There was no significant difference between
the treatments when frozen at -10C or -15C. These results show that ice
nulceators alone can significantly increase freezing tolerance in Geukensia
but do not explain the entire increase in freezing tolerance of winter
acclimatized animals.
P1.84 MCCORMICK, S.K.; WILLIAMS, L.; AYERS, T.*; Arizona Western
College, Northern Arizona University; [email protected]
Investigating the Species Boundaries Between Platanthera zothecina
and Platanthera sparsiflora
The rare alcove bog orchid, Platanthera zothecina, has been recognized as a
separate species from the widespread montane P. sparsiflora because P.
zothecina has a larger column size, spur length, and larger, thicker leaves.
We sequenced two different regions of DNA to test whether P. zothecina is,
in fact, a distinct species from P. sparsiflora. Both regions showed little
variation and grouped some populations of P. zothecina with populations of
P. sparsiflora. The DNA data suggests that P. sparsiflora has adapted to low
elevation springs in the desert multiple times and thus P. zothecina should
more appropriately be treated as a low elevation subspecies instead of a
distinct species.
P1.146 MCCORMICK, Stephen D.*; CHRISTENSEN, Arne K.; REGISH,
Amy; USGS, Conte Anadromous Fish Research Center, Turners Falls, MA,
Univ. of Massachusetts, Amherst; [email protected]
Presence of a freshwater and a seawater isoform of Na+,K+-ATPase in
the gills of a teleost fish.
The sodium pump, Na+,K+-ATPase (NKA) in the gills of teleost fish is
involved in ion regulation in both fresh water and seawater. The main
catalytic subunit of NKA is the α subunit, and recent molecular studies
indicate isoforms of this subunit may be differentially regulated by
environmental salinity. We have developed and validated antibodies specific
to the NKA α-1a and NKA α-1b isoforms of Atlantic salmon, and used
Western blots and immunohistochemistry to characterize their size,
abundance and localization. The abundance of gill NKA α-1a was higher in
fresh water than in seawater, whereas NKA α-1b was more abundant after
seawater acclimation. NKA α-1a was present in most chloride cells in fresh
water on both the filament and lamellae, but largely absent in seawater
chloride cells. NKA α-1b was present in a small number of filamental chloride
cells in fresh water (that were distinct from cells with NKA α-1a), but was
found in all of the large filamental chloride cells in seawater. The results
provide evidence for salinity-specific isoforms of Na+,K+-ATPase that may
have distinct functions for ion uptake and secretion. Preliminary data on the
regulation of these subunits by cortisol will also be presented.
e270
P2.20 MCDONALD, Michelle R.*; MCCLINTOCK, James B.; AMSLER,
Charles D.; RITTSCHOF, Daniel ; ANGUS, Robert A.; ORIHUELA, Beatriz ;
Univ. of Alabama at Birmingham, Duke Univ. Marine Laboratory;
[email protected]
Effects of ocean acidification on larval development and settlement of
the common intertidal barnacle Amphibalanus amphitrite
Increased levels of anthropogenic CO 2 released into the atmosphere are
anticipated to result in the increased acidification of the world's oceans.
Marine invertebrates that produce calcified body parts may be particularly
vulnerable. Barnacles are an ecologically important group of calcified marine
invertebrates that are potentially vulnerable to acidification. We examined
aspects of larval development (nauplii and cyprids) and juvenile settlement in
the common intertidal barnacle Amphibalanus (=Balanus) amphitrite reared
in ambient seawater (pH = 8.4) and acidified seawater (pH = 7.4) conditions.
pH levels were regulated by bubbling air containing different concentrations
of CO 2 into experimental and control beakers containing groups of 800
naupliar larvae each and fed diatoms (Skelotosema costatum). Development
of nauplii and cyprids was significantly delayed in the 7.4 pH treatment.
Moreover, fewer cyprids settled and metamorphosed into juvenile barnacles
at pH 7.4. Our findings indicate that early development and juvenile
settlement in A. amphitrite are negatively impacted by exposure to pH 7.4, a
level of ocean acidification expected to occur in the next two hundred years.
P2.32B MCDONALD, A.A*; ATCHISON, L.A.; CHANG, E.S.; COVI, J.A.;
MYKLES, D.L.; Colorado State University, Fort Collins, UC Davis Bodega
Marine Lab, Bodega Bay; [email protected]
Comparative analysis of NOS signaling in the crustacean molting gland
Molting in crustaceans is regulated by ecdysteroids produced in the Y-organs
(YO) located in the lateral cephalothorax. Ecdysteroid secretion by the YO is
suppressed in the presence of molt-inhibiting hormone (MIH), a neuropeptide
produced in the X-organ of the eyestalk ganglia (EG). The binding of MIH to
its cell surface receptor in the YO activates a signal transduction cascade,
resulting in decreased production of ecdysteroids. Recent research indicates
that the pathway may involve nitric oxide synthase (NOS), an enzyme which
catalyzes the production of nitric oxide from oxygen and arginine and is
known to be expressed in the YO. Additional research shows that the
sensitivity of the YO to MIH varies over the molting cycle. Increases in
expression of signaling proteins such as NOS could increase sensitivity of
the MIH pathway. To illuminate the role of NOS, we eyestalk ablated (ESA)
two species of decapod crustaceans, the land crab Gecarcinus lateralis and
green crab, Carcinus maenas. Eyestalk ablation removes the endogenous
source of MIH and activates the YO. Expression of NOS is quantified with
real-time PCR. Preliminary results indicate that ESA increases expression of
NOS mRNA in the land crab. Supported by National Science Foundation.
(IBN-0342982 and IOS-0745224)
P3.55 MCELROY, Eric ; College of Charleston; [email protected]
Limb morphology and ground reaction forces in lizards: forelimbs vs.
hindlimbs
Quadrupeds typically exhibit forelimbs and hindlimbs with different
morphologies. These morphological differences are expected to be related to
the demands of supporting and propelling the body. For example, running
animals exhibit a period of braking force followed by accelerative force which
is related to the differential function of fore vs. hind limbs. However, the
morphological basis for differential function remains poorly understood. This
study explores how morphological differences in the fore- vs. hindlimb are
related to differences in individual limb ground reaction forces using a
comparative approach. Musculoskeletal limb morphology was quantified for
seven species of lizards. In addition, individual limb three-dimensional
ground reaction forces (fore- or hindlimb) were quantified for each species as
they sprinted down a 3-meter racetrack. Forelimbs exhibited net braking
forces whereas hindlimbs exhibited net accelerative force. Surprisingly,
lateral forces showed a phylogenetic signal: the four Iguanian had
hindlimb-dominated lateral forces whereas lateral forces were roughly
equally distributed between fore vs. hindlimbs in the other species. These
differences in fore-aft and lateral forces can be explained by the relatively
greater length and mass of the hindlimbs in all species, with the greatest
difference in the Iguania. Only some species showed differences in vertical
forces between the fore- and hindlimbs and these differences were not
related to limb morphology, suggesting that other aspects of morphology
may influence differences in vertical force (e.g. head vs. tail size).
P3.140 MCGEE, MR; SCHOENFUSS, HL*; St. Cloud State University, MN;
[email protected]
Anthropogenic Chemicals Adversely Affect Predator Avoidance
Behavior of Larval Fish
When aquatic organisms are exposed to common anthropogenic chemicals,
how will that exposure affect innate survival behaviors? To investigate this
question, short-term exposures (12 days) subjected larval fathead minnows
Pimephales promelas to environmentally relevant concentrations of
chemicals, singular or in mixture, from the following two classes: (1)
estrogens or (2) anti-depressant pharmaceuticals. Following exposure,
larvae were introduced to a simulated threat stimulus (standardized
vibration). Under normal circumstances during a predator-prey confrontation,
larval fish use an escape response, the C-start, to rapidly move away from
an approaching threat. The C-start has been extensively studied and a
neuro-anatomical axis of sensor-Mauthner cell (neuron; CNS)-effector has
been identified. This behavior is also conserved across teleost lineages, and
the inability to effectively execute a C-start has direct adversary
consequences. High-speed (1,000 Hz) video recordings of larval C-start
performances were collected for frame-by-frame analysis of latency periods,
escape velocities, and total escape response. Both chemical classes
adversely affected larval total escape response; however, they exhibited
different modes of action. Estrogen exposure significantly affected larval
latency periods (up to 60% longer to react); antidepressant exposure
affected larval escape velocity (up to 63% slower). Our findings suggest that
anthropogenic chemicals have the ability to influence larval escape
performance through multiple modes-of-action. Further studies will explore
the molecular alterations on the Mauthner cell axis caused by these chemical
exposures. EPA STAR (R832741-01-0).
e271
P3.153 MCGINN, N.A.*; CHERR, G.N.; University of California, Davis;
[email protected]
Comparative physiology of multidrug resistance in marine invertebrate
oocytes and embryos
Multidrug resistance (MDR) - discovered in cancer cells resistant to multiple
chemotherapeutic agents - is important in normal cell function and in the
protective mechanisms of tissues such as the blood-brain barrier and
placenta. The efflux of target compounds that characterizes MDR is found in
a taxonomically wide range of organisms where MDR performs functions
similar to those in mammalian tissues. In marine invertebrates, MDR activity
is found in adult tissues, notably gill, but MDR is also a functional protective
mechanism in the early developmental stages of broadcast spawners. In the
sea urchin Strongylocentrotus purpuratus, MDR activity was low in
unfertilized eggs, but dramatically increased after fertilization. In sea stars,
no such increase after fertilization was observed, however, MDR activity did
increase after germinal vesicle oocytes underwent maturation in vitro. In this
study, we have taken a comparative approach to better understand how
MDR activity varies in oocytes and embryos from different phyla of
broadcast-spawning marine invertebrates. As in S. purpuratus, MDR activity
in the eggs of the sea urchin Lytechinus pictus was significantly greater after
fertilization, although the level of MDR activity was lower overall. In contrast,
there was no increase in MDR activity post-fertilization in either the mussel
Mytilus galloprovincialis or the echiuran worm Urechis caupo. While the
overall level of MDR activity in M. galloprovincialis approaches that of L.
pictus, U. caupo activity was consistently lower. These differences may be a
result of the maturational state of the oocytes/eggs or, perhaps, the exposure
of adults to MDR substrates. We continue to investigate species with
different reproductive strategies with a focus on oocyte maturation.
P2.164 MCGUIRE, N.L.*; UBUKA, T.; PERFITO, N.; BENTLEY, G.E.;
University of California, Berkeley , Helen Wills Neuroscience Institute and
University of California, Berkeley ; [email protected]
A novel neuropeptide system within the gonads: GnIH and GnIH-R in
passerine songbirds
Many hormones that are classified as neuropeptides are synthesized in
vertebrate gonads in addition to the brain. Receptors for these hormones are
also expressed in gonadal tissue; thus there is potential for a highly localized
autocrine or paracrine effect of these hormones on a variety of gonadal
functions. In the present study we focused on gonadotropin-inhibitory
hormone (GnIH), a neuropeptide that was first characterized as a
hypothalamic regulator of pituitary function in birds. Here we present
molecular, histological and physiological evidence for the presence and
functional significance of a GnIH system in avian gonadal tissues. The
presence of GnIH and its receptor, GnIH-R, in gonadal cells of passerine
birds suggests a role for this system in the local regulation of sex steroid
synthesis. Data from gonadal culture support this conclusion. Thus gonadal
GnIH may fine-tune reproductive physiology and behavior via local regulation
of steroid synthesis and its subsequent release into the periphery.
P2.48 MCHUGH, D.*; SCHULT, N.; PERNET, B.; Colgate University,
California State University, Long Beach; [email protected]
Poecilogony as a window on larval evolution: Comparative analyses of
gut development in Streblospio benedicti (Spionidae, Annelida)
As a poecilogonous species, Streblospio benedicti (Spionidae, Annelida)
provides an excellent opportunity to explore evolutionary transitions in larval
developmental modes in marine invertebrates. Within a single population,
females of S. benedicti produce either larvae that develop from large, yolky
eggs (100-200 um) and spend only a few hours or days in the plankton
without any need to feed, or larvae that develop from small eggs (60-70 um)
and spend days to weeks feeding in the plankton before metamorphosis. In
comparative analyses of morphogenesis and gene expression patterns, we
are assessing similarities and differences between the two contrasting larval
developmental modes. Because one of the key traits that differs between the
two larval types is the timing of formation of a functional gut, we are focusing
on gut development. Using phalloidin labeling and immunohistochemical
techniques, we identify comparable developmental stages in the two larval
types and reconstruct gut development for these stages. For genes involved
in gut patterning (foxA, hedgehog, Tbox6), we use quantitative PCR to
record transcript levels and in situ hybridization to document the patterns of
expression at specific developmental stages in both larval types. This work is
bringing us closer to explaining the evolution of larval diversity in marine
invertebrates.
P3.185 MCINTYRE, Alyssa*; MCGEE-MOORE, Alana; COOPER, W.
James; ALBERTSON, R. Craig; Syracuse University; [email protected]
The Evolution of Skull Form and Trophic Ecology Among the Cichlid
Fishes of Lake Malawi
An organism's unique skeletal and muscular structures form a biological
machine capable of interacting with its environment. When an animal's
anatomical form changes, the resulting modification in biomechanical
function can allow it to occupy a new ecological niche. The cichlid fishes of
Lake Malawi are an extraordinary example of rapid evolutionary divergence.
In a very short span of evolutionary time (1-2 million years), one species has
diversified into several hundred species that inhabit an extremely wide
variety of feeding niches. This ecological divergence was produced by a
massive radiation in skull form and function. We studied the anatomical
diversity of this incredible lineage by dissecting and photographing the skulls
and jaws of 102 fishes from 47 of the 53 cichlid genera found in Lake Malawi.
The genera examined contain 93% of the cichlid species that are native to
the lake. We examined anatomical landmarks that are of biomechanical
importance for fish feeding using geometric morphometric analyses, which
are coordinate based mathematical analyses of anatomical form. Our results
provide a nearly comprehensive measurement of the anatomical diversity of
Lake Malawi cichlid skulls, and provide a quantitative description of a classic
example of an adaptive radiation. The results confirmed a significant degree
of variation among cichlid genera, and indicate that the two major lineages of
Lake Malawi cichlids, the "rock dwellers" (mbuna) and the "sand dwellers",
have each evolved skull shapes that are not possessed by the other, and
these morphologies have allowed each of them to exploit unique ecological
opportunities.
e272
P3.35 MENDOZA BLANCO, M/A*; PATEK, S/N; Univ. of California,
Berkeley; [email protected]
Muscle mechanics in mantis shrimp
Mantis shrimp (Stomatopoda) capture a wide range of prey depending on the
particular morphology of their thoracic appendages. Smasher mantis shrimp
have hammer-like appendages used to deliver powerful blows while spearers
have elongated, spiny appendages for piercing or grabbing prey. The lateral
extensor muscle powers these strikes and occupies up to 90% of the muscle
weight inside the merus segment. The extensor muscle compresses springs
and linkages which are then rapidly released by latches controlled by flexor
muscles. One fundamental question in this system is whether the lateral
extensor muscle limits strike performance across species, given the dramatic
variation in feeding strategies. Our goal was to compare the physiological
cross-sectional area (PCSA) of the lateral extensor muscle in the raptorial
appendage of a smasher (Gonodactylaceus falcatus) and a spearer
(Pseudosquilla ciliata) and to examine body size scaling in PCSA within
these two species. PCSA was calculated by measuring the apodeme area
and the mean pinnation angle of the lateral extensor muscle. The pinnation
angle was similar in both species (37-38) and it did not vary across a nearly
two-fold range of body lengths in each species. The relationship between
PCSA, apodeme area and merus length were indistinguishable between the
two species. PCSA and apodeme area were positively correlated with body
size in P. ciliata and approached significance in G. falcatus. Interestingly, the
merus was larger relative to body size in the smasher, G. falcatus, than in
the spearer, P. ciliata, resulting in a gradeshift in all parameters relative to
body size except for pinnation angle. Thus, the smasher has larger
appendages and greater PCSA than in a similar-sized spearer, but the
muscle mechanics remain similar across appendage sizes in these two
species.
P1.134 MEREDITH, AM*; KRAJNIAK, KG; Southern Illinois Univ.
Edwardsville; [email protected]
The Cholinergic Receptor Transduction System in the Earthworm
Gizzard
In the earthworm, Lumbricus terrestris, acetylcholine stimulates the
contraction rate of the crop-gizzard and causes a biphasic change in
amplitude with an increase at low concentrations and a decrease at high
concentrations. Since many cholingeric receptors are linked to the production
of second messengers we decided to see if known inhibitors of transduction
pathways could alter the mechanical responses of isolated gizzard rings to
acetylcholine stimulation. When exposed to the adenylyl cyclase inhibitor,
MDL-12,330A, the rate of contraction after an acetylcholine application was
markedly decreased. Even after all of the inhibitor was washed away, the
subsequent application of acetylcholine did not result in a contraction
amplitude as high as the initial 10-6 M application of acetylcholine. These
results suggest that a cyclic AMP pathway might be responsible for
acetylcholine induced responses. They also suggest that the earthworm
gizzard receptor may not be linked to the same second messenger system
found in mammals where acetylcholine causes a decrease in the cyclic AMP
due to the inhibition of adenylyl cyclase.
P3.142 MERLIE, S.A.*; RYAN, K.A.; SMITH III, J.P.; Winthrop University;
[email protected]
Neoblasts in Catenulida
Our current understanding of the stem-cell (neoblast) system in
Platyhelminthes comes primarily from a wealth of experiments on
regeneration in members of the Tricladida, supplemented by studies of
members of other groups. To date, there are relatively few studies of the
neoblasts in the potentially-primitive Catenulida. Accordingly, we have
carried out M-phase (anti-phosphoH3) and putative S-phase (anti-PCNA)
labeling experiments in Stenostomum virginianum and Catenula lemnae,
supplementing these light-microscopic histochemical studies with electron
microscopy. We have also studied neoblast dynamics in starved and fed S.
virginianum. Neoblasts were observed in the gastrodermis and parenchyma
of both species by both light-microscopic immunohistochemistry and by
electron microscopy. In addition, S. virginianum was found to possess
neoblasts in the epidermis, consistent with previous light- and
electron-microscopic observations of dividing cells in the epidermis of various
catenulid species. Following prolonged starvation, neoblast mitoses in S.
virginianum recovered in a biphasic fashion, with mitoses peaking at 3 hours
and 24 hours post-feeding, in a pattern reminiscent of that in triclad
flatworms. Collectively, these data support the hypothesis that the neoblast
stem-cell system may be a synapomorphy for the Platyhelminthes.
(Supported by a Grant from the Winthrop University Research Council)
P3.171 MERZ, R.A.*; HUSSAIN, F.N.; STOCKBOWER, K.A.; TASCHUK,
F.O.; YARETT, I.R.; SANTOS, S.R.; XIANG, Y.; VALLEN, E.A.; Swarthmore
College, Auburn University; [email protected]
The patchy distribution of zooxanthellae in the gastrodermal landscape
of symbiotic anemones
The intimate symbiotic association of cnidarians and intracellular
photosynthetic dinoflagellates produces local sinks and sources of materials
different from adjacent symbiont-free cells. Are these metabolically active
symbionts evenly distributed in the gastrodermal tissue of tentacles? We
examined the density of Symbiodinium clade B cells in the tentacles of wild
sea anemones (putatively Aiptasia sp.) from Beaufort, N.C.. Using confocal
microscopy to view the naturally fluorescing zooxanthellae in the tentacles of
30 animals, we examined the distribution of algal cells in three regions of
each tentacle (adjacent to the oral disc, near the tip of the tentacle and
midway between the two points). At each site we counted algal cells in
replicate microquadrants within the gastrodermal layer (n=30 counts per
tentacle). In more than half the tentacles from recently collected animals,
there were significant differences in the density of algal cells in different
regions of tentacles (densities from 0 to 30 algal cells per 160 2 ). This
distribution was not predictable, the highest or lowest algal density could fall
at any place along a tentacle. In addition two tentacles (selected at random)
from the same animal were significantly different in their algal densities in
about a third of the animals. Intra-tentacular regional differences were least
common in the darkest animals and may therefore reflect something about
the mechanism by which the host dynamically acquires, evicts or regulates
cell division of algal cells.
e273
P2.77 MIDDLETON, K.M.*; CONNERS, M.; SWARTZ, S.M.; California State
University, San Bernardino, Brown University; [email protected]
Variation in rachis cross-sectional geometry within and among flight
feathers in the Barn Owl (Tyto alba)
As the primary component of the avian aerodynamic lift generating surface,
feather anatomy has been shaped by tradeoffs between mechanical and
energetic constraints. Characteristics that would favor increased rigidity and
resistance to buckling, stiffer material components and larger cross-sectional
areas or second moments of inertia, are energetically more costly as these
materials must be oscillated many times per second during flight. We studied
variation in cross-sectional geometry of the rachis in both primary and
secondary feathers of the Barn Owl (Tyto alba). Feathers were sectioned at
five different locations along the length of the rachis either with a low-speed
saw after embedding in epoxy or with a scalpel. Cross-sections were
photographed under a dissecting microscope, and cross-sectional areas
(XSA) and second moments of inertia (I) were calculated. Using published
values for Young's modulus (E) of feather keratin, we estimated flexural
stiffness (E * I) at each location. All feathers exhibited a strong proximodistal
gradient in both XSA and I, with commensurate decreases in flexural
stiffness, with rachis tips approximately two orders of magnitude smaller than
proximal ends. Between-feather variation correlated well with published
values for aerodynamic pressures; distal primaries were stiffer than proximal
primaries, which, in turn, were stiffer than secondaries.
P3.7 MIKA, T.L.*; REIBER, C.L.; University of Nevada, Las Vegas;
[email protected]
Physiological limitations to cardiovascular function in thermally
stressed grass shrimp (Palaemonetes pugio)
Failure of the crustacean cardiovascular system at temperature extremes
may be attributed to several different factors including failure at the cardiac
ganglion, failure of myocardial contractile mechanisms, or physical limitation
to cardiac function. Oxygen delivery rates must keep pace with the increased
metabolic rate observed in poikilothermic animals exposed to increased
temperature if aerobic metabolism is to be maintained. One possible
mechanism for cardiac failure may be a physical failure of the oxygen
delivery system to meet this increased demand. Oxygen delivery is a
function of cardiac output, which is in turn a function of both heart rate and
cardiac stroke volume. Critical thermal maximum temperatures (CT max),
metabolic rates, and cardiac parameters (heart rate, stroke volume, cardiac
output, ejection fraction and pressure-volume loops) were determined in
grass shrimp (Palaemonetes pugio) acclimated to 20 C over a temperature
range (5-40 C) to identify when and how the cardiovascular system failed.
Stroke volume appears to be temperature insensitive in normoxic animals,
leaving cardiac output dependent on heart rate. As heart rate increases,
diastolic filling time decreases to a point where stroke volume can no longer
be maintained, leading to a decline in cardiac output and decreased oxygen
delivery. To determine if cardiac failure is indeed the result of decreased
oxygen delivery, animals were subjected to the same experiments in a
hyperoxic environment. CTmax was determined, and cardiac parameters were
measured over the temperature range. Animals placed in a hyperoxic
environment had a higher CTmax than animals in a normoxic environment,
suggesting a physical limitation in oxygen delivery.
P2.172 MILLER, WA*; TERWILLIGER, NB; University of Oregon,
Charleston, Universtiy of Oregon, Charleston; [email protected]
Effects of molting and salinity stress on the expression of HIF, molting,
and immune response genes in juvenile Cancer magister
Hypoxia inducible factor, HIF, is known to regulate gene expression in
response to hypoxia in vertebrates and invertebrates, but its role in
multi-stress regulation is not fully understood. HIF involvement in normoxia
has been shown under specific stress conditions in mammals and fish.
Molting and salinity stress in Cancer magister require extensive
morphological and metabolic changes. We hypothesize that in juvenile
Dungeness crabs, which undergo multiple molt cycles in estuarine habitats of
varying salinities, HIF participates in the molecular response to molting and
salinity stress. This study investigated the mRNA expression of HIF alpha in
juvenile C. magister when stressed under normoxic conditions. Based on
recent microarray evidence showing stress-specific changes in gene
expression of cryptocyanin 2, arthrodial membrane 6, and
anti-lipopolysaccharide (anti-LPS) in C. magister (Phillips, 2007), we also
monitored their mRNA levels. One cohort of 1st instar juveniles was
maintained across the entire molt cycle. Beginning at ecdysis and daily until
2nd instar, crabs were sampled for total RNA. A second cohort of juvenile C.
magister was exposed to 50% seawater for 3, 8, and 24 hours, and then
sampled for total RNA. After reverse transcription, cDNAs of HIF alpha,
molting and immune defense genes were analyzed by real-time quantitative
PCR. HIF alpha, cryptocyanin 2, arthrodial membrane 6, and anti-LPS all
showed changes in mRNA expression during the molt cycle and
gene-specific changes in expression in response to salinity stress. Supported
by MDIBL NIA (NBT).
P2.96A MING, Q.L.*; TIGREROS, N.; FEDINA, T.; LEWIS, S.M.; Tufts
University, Medford, MA 02155 USA; [email protected]
Genetic and Nutritional Influences on Male Reproductive Performance
in Tribolium flour beetles
The evolutionary maintenance of genetic variation for male sexual traits in
the face of directional selection represents a long-standing paradox. One
possible mechanism responsible for maintaining such variation is
genotype-environment interactions (GEI), which can maintain variation
because some male genotypes perform better in certain environments while
different genotypes do better in other environments. However, few studies
have examined the role of GEI in maintaining variation in male sexual traits.
In these experiments, we used Tribolium flour beetles to examine the
contribution of genotype and nutritional environment to several larval and
adult traits as well as to male mating and post-mating reproductive
performance. Using a split-brood design for siblings reared on high, medium
and low nutritional diets (created by manipulating ratio of flour to non-nutritive
microcrystalline cellulose), we estimated genetic and environmental variation
and GEI. Quantitative genetic analyses revealed significant genetic and
nutritional contributions to larval mass, larval growth rate, and larval
development time. Male reproductive performance was influenced both by
diet, which affected mating rate, and genotype, which affected insemination
success. Nutritional quality of the rearing environment had a significant effect
on both adult resistance to starvation and weight reacquisition. The absence
of GEI for most male traits suggests that other mechanisms, including
condition-dependence, may be responsible for maintaining trait variation in
Tribolium flour beetles. This study not only helps us understand how different
environments influence Tribolium male traits and reproductive performance,
but also provides new insights into how sexual selection changes across
different environments.
e274
P2.123 MINIUM, Sasha*; BASH, Ryan; SHANBHAG, Pratima; KERKHOFF,
Andrew J.; ITAGAKI, Haruhiko; Kenyon College; [email protected]
The scaling of growth, nutrient assimilation and metabolism in larval
hawkmoths raised on natural and artificial diets
Recent theory attempts to explain metabolic scaling based on the
evolutionary optimization of the structure and function of resource supply
networks and exchange surfaces. However, we know of no studies that have
simultaneously examined the scaling of both metabolism and resource
exchange between animals and their environment. We use the larvae of
tobacco hawkmoths (Manduca sexta), which grow ca. 10,000-fold in mass in
18 days, to investigate whether metabolic scaling is related to developmental
changes in nitrogen (N) and carbon (C) assimilation and excretion. To
examine the effects of diet quality (C:N), we also imposed a diet treatment,
raising caterpillars on either a stock laboratory diet or on the leaves of
tobacco (Nicotiana tobacum) a natural hostplant. Animals fed tobacco grew
more slowly, and though they grew for a longer period, they reached a
smaller asymptotic size. Tobacco fed animals also displayed metabolic
scaling exponents shallower than those of animals fed the standard
laboratory diet, which is consistent with other studies documenting the effect
of food quality on metabolic scaling. The scaling of excretion (frass
production) was similar to the scaling of metabolism, while the scaling of
ingestion was shallower. Together, these results lead to a relatively simple
model of ontogenetic growth and point to the potential importance of the
stoichiometry (C:N balance) of nutrient uptake for understanding metabolic
scaling and growth. This study is part of a larger NSF-funded undergraduate
interdisciplinary research and training project (Manduca InSTaRs) assessing
the role of midgut morphology and function in metabolic scaling.
P3.183 MIYAGI, R*; TERAI, Y; AIBARA, M; MIZOIRI, S; SUGAWARA, T;
IMAI, H; WACHI, N; TACHIDA, H; OKADA, N; Tokyo Institute of Technology,
Yokohama, Kyoto University, Inuyama, Kyusyu University, Fukuoka;
[email protected]
The diversity of visual perception in sympatric Lake Victoria cichlids
Lake Victoria harbors hundreds of endemic species of cichlids which have
experienced explosively adaptive radiation during a very short period. They
are ecologically and morphologically highly diverse whereas genetic
differentiations among species are extremely low. Lake Victoria cichlids are
one of the well-studied organisms at the genetic mechanisms of sensory
drive speciation. In allopatric and parapatric distribution cases, the
adaptation of visual systems and the evolution of nuptial color might cause
reproductive isolation that lead to speciation. We studied the diversity of
visual system in sympatric cichlids that has not been reported. We
determined the sequences of opsin genes, which code photoreceptor
proteins, from seven sympatric species. The LWS and RH1 genes showed
the species-specific amino acid replacements, and showed higher degree of
diversification between each species than those in neutral regions.
Especially in two species, the divergent natural selection has acted on LWS
gene regions detected by population genetic analysis using LWS and its
flanking regions. The LWS pigments reconstituted from LWS of those two
species absorbed different spectra suggesting functional diversification.
These results suggest that even in sympatric cichlids had species-specific
visual perception. The visual systems of sympatric cichlid species might have
adapted not only to light environments but also to species-specific
microhabitats including ecological features such as feeding and mating
behaviors.
P1.147 MIZRAHY, Ortal*; BAUCHINGER, Ulf; PINSHOW, Berry; Ben-Gurion
University ; [email protected]
Water availability is not a bottle-neck to rebuilding fat stores in
insect-eating, migrating blackcaps
Migrating birds stopover to rebuild lost tissue, and access to drinking water
positively affects fat accumulation. Before fat is accrued, birds must rebuild
their digestive tracts (GIT). We used 30 freshly caught, migrating blackcaps
(Sylvia atricapilla) to test the prediction that after a simulated in-flight
starvation period the rebuilding of the GIT is faster in birds with access to
drinking water than without. Ten birds were randomly assigned to each of
three groups receiving: water ad libitum, 30 min access to water per day, or
no water. All three groups were fed mealworms ad libitum for the 6-day
experiment. Mean daily water intake was significantly different among the
groups (5.42±1.0 g; 0.81±0.1 g and 0 g; Holm-Sidak test, F=165, p<0.001).
Despite this, there were no differences in daily food intake (ANOVA
F (2,28) =0.23, NS). Furthermore, in all groups, mean food intake almost
doubled from day 1 to day 2, remained high until day 4, and declined on days
5 and 6. Body mass in all groups increased continuously from day 1 to day 6
(15.5±1.0 g to 19.4±1.2 g, ANOVA F(1,58)=190.76, p<0.0001) and did not
change on day 7 (19.4±1.2 g to 19.6±1.3 g, ANOVA F (1,58) =0.28, NS),
suggesting that tissue replacement was complete. Visual fat score increased
similarly in all three groups (from 0±0.45 to 3±1.2, ANOVA F(2,28)=0.47, NS).
The data did not support our prediction in that there were no apparent
differences in body mass and fat score between the groups. Although
preformed and metabolic water gained through eating mealworms is
apparently sufficient for blackcaps to rebuild their digestive organs and fat
stores, given access to water the birds drink prodigiously, perhaps allowing
more time for activity.
P2.154 MONETTE , Michelle Y.*; FORBUSH, Biff; Yale School of Medicine
and Mt. Desert Island Biological Laboratory; [email protected]
Phosphorylation state of Na-K-Cl cotransporter in the intestine of
euryhaline teleosts in response to varying osmolality
The Na-K-Cl cotransporter (NKCC) couples the movement of Na, K, and Cl
across polarized cell membranes. Two NKCC isoforms have been cloned:
NKCC1, a ubiquitously expressed secretory isoform with an important role in
the regulation of intracellular Cl and cell volume, and NKCC2, a
kidney-specific absorptive isoform expressed in the thick ascending limb of
the loop of Henle. In teleosts, NKCC2 is present in the apical membrane of
the intestine where it functions in osmo- and iono- regulation. Estuarine
teleosts, experience rapid salinity changes and must be able to regulate
plasma ion concentrations. To cope with hyperosmotic stress, teleosts drink
seawater, absorb Na and Cl via apical NKCC2 in the intestine, and secrete
excess ions via the gill. It is hypothesized that rapid activation of NKCC2 is
achieved in part by protein phosphorylation, as has been demonstrated for
NKCC1. This study examined the in vitro and in vivo phosphorylation state of
NKCC in the intestine of killifish and flounder in response to varying
osmolality using immunological techniques and detection with NKCC
antibodies, R5 (phospho-specific) and T4. Phosphorylated NKCC was highly
expressed in the intestine of killifish and flounder. Exposure of killifish and
flounder intestine to high osmolality in vitro resulted in a reduction in R5
signal, whereas no effect on T4 signal was observed. Loss in R5 signal after
incubation in high osmolality was almost fully reversible after a subsequent
incubation in low osmolality. These data demonstrate changes in the
phosphorylation state of NKCC in the intestine of euryhaline teleosts upon
exposure to varying osmolality, supporting the hypothesis that
phosphorylation plays a role in regulating NKCC during acute salinity
changes.
e275
P1.63 MONROY, J.A.; UYENO, T.A.*; NISHIKAWA, K.C.; Northern Arizona
University; [email protected]
Muscle architecture and spring properties during active shortening
Active cross-striated muscle recoils elastically during rapid unloading.
Previous analyses show that this spring-like property of actively shortening
muscle is remarkably similar in vertebrate muscles (mouse soleus, EDL; frog
depressor mandibulae, sartorius). Here, we expand our studies to
invertebrate cross- and obliquely striated muscles. The cross-striated
abdominal extensors and flexors of crayfish are used in rapid locomotory tail
flips. The rigidly parallel sarcomere organization that produces the
cross-striated muscle pattern suggests functionality similar to vertebrate
skeletal muscle. The obliquely striated longitudinal muscle fibers of the
earthworm body wall are used in peristaltic locomotion. Here, the
sarcomeres are offset, which allows thick filaments to shear relative to each
other and generate force over a large range of lengths. If the sarcomere
arrangement plays a role in muscle elasticity, we would expect that muscle
stiffness and the mechanism(s) for generating elasticity to differ between
cross- and obliquely striated muscles. We used load-clamp experiments to
measure the displacement of isolated muscles during recoil following sudden
drops in load. We then calculated muscle stiffness across a range of muscle
forces and lengths. Our results show that, regardless of sarcomere
arrangement, all muscles tested respond similarly to changes in load. Muscle
displacement increases exponentially as the change in force increases,
resulting in non-linear increases in muscle stiffness with load. Thus, the
ability to recoil elastically during rapid unloading appears to be a general
feature of cross- and obliquely striated muscle in animals. The mechanism of
muscle elasticity does not appear to be affected by differences in sarcomere
organization. Supported by NSF IOS-0623791, IOS-0732949.
P2.155 MONSON, SM*; POWERS, DR; SCHMITT, JM; KIMBERLY, DJ;
George Fox University, Newberg, OR; [email protected]
Distribution of aquaporin water channels in osmoregulatory tissues of
the rough-skinned newt (Taricha granulosa)
In urodeles, the ventral skin, kidneys, and intestine are important
osmoregulatory organs that play a key role in the maintenance of water
balance. Because of the ease with which water moves across these tissues it
is expected that a variety of aquaporin water channels (AQP) act as a
gateway for bulk water flow through tissue surfaces. To better understand
the role of AQPs through these tissues we examined the distribution of AQPs
in each of these tissues. Specifically we focused on homologs to mammalian
AQPs 1,2, and 4 which play important roles in the mammalian kidney. AQP 2
was of particular interest because it is hormonally regulated in mammals and
might be used to control water flow in aquatic and extremely moist
environments as well as in arid conditions. To do our work we field collected
rough-skinned newts (Taricha granulosa) and harvested immediately ventral
skin, kidney, and intestine. Standard procedures were used in performing
western blots to demonstrate the presence of AQP in these tissues. Western
Blot showed AQP 1 and AQP2 to be relatively abundant in the bladder,
kidney, and intestine and have lower levels of expression in the ventral skin
relative to ERK 1 and ERK 2. However, they appeared to be present in all
tissues examined. AQP1 localization in the ventral skin appeared in the
epithelia along with AQP2 and AQP4. Newt kidney showed clear localization
of AQP1 and AQP2 around the proximal and distal convoluted tubules.
Localization of AQPs 1 and 2 appeared lining the lumen of the intestine
along with AQP4 in the smooth muscle of the cross section. The knowledge
of the urodele model can only broaden our scope and understanding of
AQPs in amphibians and the physiology of animals in general.
P1.90 MONSON, Emilee*; GERKEN, Sarah; University of Alaska Anchorage;
[email protected]
The presence of penial lobes in two new Lampropid species
(Crustacea: Cumacea), Lampropenis sp. A and Lampropenis sp. B,
from the shores of the Pribilof Islands, Alaska.
A new genus and two new species of lampropid cumaceans (Lampropenis
sp. A, Lampropenis sp. B) are described of specimens from the collections of
the Smithsonian National Museum of Natural History. The samples were
collected in 1917 from the Pribilof Islands, St George and St. Paul, Alaska.
Cumaceans are small marine crustaceans. Their length can range from
1mm-30mm, with the larger specimens generally residing in deeper, colder
waters. Female cumaceans brood eggs inside a brooding pouch called a
marsupium; it is common for the larvae to remain in the marsupium for at
least 1 molt. Females in some species may have up to 3 brooding molts,
while the males adult molt is thought to be terminal. Sexual dimorphism is
highly variable between species. In some species there may be very few
morphological differences between the adult males, females, and juveniles.
In other species the sexual dimorphism can be drastic. In the family
Lampropidae it is common for males to have specialized second antennae,
and as many as 3 pleopods. It is thought the second antennae may be useful
in detecting a mate and the pleopods aid in motility. Females generally lack
pleopods and have small antennae. A defining characteristic of this new
genus is the presence of a pair of penial lobes on the fifth pereonite in the
males. This character is uncommon amongst cumaceans, currently
described from only two species, Archaeocuma peruana Bacescu 1972 and
Campylaspenis rowei Bacescu and Muradian 1974.
P3.125 MOOI, R.; California Academy of Sciences; [email protected]
The Summer Systematics Institute: Hands-on, collections-based
undergraduate research at the California Academy of Sciences
With world-wide threats to biodiversity and growing interest in the origins and
diversification of life, phylogenetic systematics and evolutionary biology have
become critical components of undergraduate education. More than 12 years
ago, to help address these issues, the California Academy of Sciences
launched the Summer Systematics Institute (SSI) with support from NSF's
Research Experiences for Undergraduates (REU) initiative and the
Academy's Wallace endowment. The SSI is an 8-week internship at the
California Academy of Sciences in San Francisco. The SSI has brought to
the Academy more than 100 undergraduates from almost 40 different states
to work on research with an advisor of their choice on a project relating to the
discipline of that advisor. Participants also receive instruction while taking
part in a museum-based curriculum that includes tours, lectures, and lab
exercises on phylogenetic systematics, molecular techniques, biodiversity,
evolutionary biology, global change, and other contemporary issues in the
natural sciences. In the past 4 years, 9 of the undergrads attended the SICB
meeting that followed their summer internship and presented their findings in
the form of talks and posters. Among the 28 participants of the past 4 years,
26 different universities and colleges are represented from 15 different
states. The Academy has just opened its state-of-the-art new museum in
Golden Gate Park, and this exciting REU Site will continue to offer
undergrads, particularly those from groups under-represented in the
sciences, important insights into the contributions that museum-based
research can make to issues facing society today.
e276
P2.133 MOON, Brad R.*; HAMPTON, Paul M.; Univ. Louisiana, Lafayette;
[email protected]
The Effects of Long Tendons on the Energetic Cost of Muscle
Contraction
Muscles that have long tendons often shorten less than muscles with short
tendons, which suggests that muscles with long tendons have a lower cost of
contraction. However, in most muscles it is difficult to separate the effects of
fiber type and tendon length on contractile cost. The shaker muscles in the
tails of rattlesnakes are good models for studying how tendon length affects
contractile energetics because they vary along the tail in tendon length but
have a single dominant fiber type, which provides a natural control that is
lacking in typical muscles. Shaker muscle segments with long tendons were
found previously to shorten significantly less than segments lacking tendons.
We are now testing the hypothesis that muscles with long tendons have a
lower contractile cost than segments without tendons. We are using
denervation and selective paralysis to block the contraction of muscles
segments while measuring oxygen consumption in western diamond-backed
rattlesnakes (Crotalus atrox). By carefully measuring and subtracting the
metabolic rates under different conditions (resting, all shaker muscles active,
only muscles with long tendons active, and all muscles blocked), we can
partition the cost of contraction between muscles that have long tendons and
no tendons. Our early results indicate that (1) shaker muscles have
metabolic rates that are high enough to allow selective paralysis without loss
of metabolic signal strength, (2) denervation of the distal-most muscles
segments does not alter the activation or contractile strains of more proximal,
intact segments, and (3) the cost of contraction in segments with long
tendons is lower than in segments without tendons. The results on a larger
sample are likely to be representative of other fast muscles, which appear to
be relatively common in diverse lineages of animals.
P1.74 MOORE, A.M.*; BARRY, B.D.; MENAKER, M.; University of Virginia;
[email protected]
Photic Niche and Photosensitivity of the Pineal Oscillator in Anolis
Species
Circadian clocks coordinate behavior and physiology such that events occur
at the appropriate time of day or night. Light is the most salient cue by which
the clock is entrained to the 24-hr day, yet the influence of environmental
light on clock evolution remains largely unexplored. To investigate the
relationship between photic niche and the physiology of a circadian
pacemaker, we have focused on the lizard pineal gland because a) it is
intrinsically photosensitive and entrains to light directly, b) its role as a
circadian pacemaker varies widely across species, and c) its rhythmic output,
melatonin, is readily quantifiable. We cultured individual pineal glands from
several species of Anolis lizards and measured melatonin output under
lighting regimes designed to reveal period, amplitude, and photosensitivity of
the pineal oscillator. We show that light suppresses nighttime melatonin
levels in all species except A. carolinensis, with considerable variation
among species in the magnitude and duration of suppression. Preliminary
analyses suggest that shade-dwelling species are more sensitive to
light-induced melatonin suppression than are sun-dwelling species, providing
initial support for the hypothesis that photic niche is correlated with circadian
photosensitivity. Future work will incorporate additional species in an attempt
to characterize the contributions of phylogenetic lineage, structural niche,
photic niche, and light history effects towards phenotypic variation in
circadian physiology.
P3.99 MOORE, M.S.*; BUCKLES, E.L.; KUNZ, T.H.; Boston University,
Boston, Cornell University, Ithaca; [email protected]
Are Hibernating Bats Capable of Mounting an Effective Immune
Response? Histological Evaluation of a Cellular Response to
Phytohemagglutinin (PHA) Injections in the Little Brown Myotis (Myotis
lucifugus) and the Big Brown Bat (Eptesicus fuscus)
White Nose Syndrome (WNS) is a recently observed condition affecting bats
in the northeastern United States that has caused up to 95% mortality in
some hibernacula. First reported in the winter of 2006-2007, bats affected
with WNS exhibit unusual behaviors, develop a fungal growth on their faces,
ears, and wing membranes, are depleted of fat reserves, and exhibit
extensive wing necrosis and scaring. It is not known whether the fungus, for
which this syndrome is named, is the cause of death or an opportunistic
condition of immuno-compromised individuals. However, bats that have the
visible fungal colonies on their noses and wings have fungal hyphae within
the dermis and epidermis and are absent of local inflammation. To test the
hypothesis that hibernating bats are unable to mount an effective
inflammatory response to the fungus because of physiological constraints
associated with deep torpor, we collected biopsies of swellings developed in
response to subcutaneously injected phytohemagglutinin (PHA) in active and
hibernating little brown myotis, Myotis lucifugus, and big brown bats,
Eptesicus fuscus. Biopsies were collected at 6, 12, and 24 hours
post-injection and analyzed histologically for variation in immune function
cells. In active bats, the response to injection is mild, but does vary
depending on time post-injection. These results will be used to describe
potential differences in inflammatory response between active and
hibernating bats, investigate possible variables associated with WNS, and
establish whether or not hibernating bats can respond to a potentially
infectious fungal condition.
P1.4 MOORE, JR*; WALTERS, JR; MOORE, IT; Virginia Tech;
[email protected]
Breeding behavior in Prothonotary Warblers: Is food availability the
key?
Global climate change has resulted in the advancement of many
phenological events in the spring such as budburst, insect emergence, and
reproductive behavior of many birds. A long-term study of the Prothonotary
Warbler (Protonotaria citrea) reveals that, over the past twenty years, males
have advanced their arrival date by approximately three weeks however
clutch initiation dates have remained unchanged. This appears to have
resulted in a mismatch between timing of breeding and peaks in food
availability. We examined whether experimentally supplementing food upon
arrival would advance breeding and associated behaviors at two different
sites in the James River Virginia watershed. Experimental pairs were
supplemented with waxworms upon arrival and nest boxes were visited 3-4
times a week to determine clutch initiation dates. In addition we measured
male aggression and testosterone levels in response to the food
supplementation. Clutch initiation dates and male plasma testosterone levels
did not differ between experimentally supplemented and control pairs. Thus it
appears that while birds are arriving earlier a lack of available food is not the
cue preventing them from advancing breeding.
e277
P1.101 MORENO, L*; NAVA, S.S.; WANG, D.; MARTINS, E.P.; Indiana
University and the Center for the Integrative Study of Animal Behavior,
Bloomington; [email protected]
Visual Laterality and Sexual Asymmetry of Signal Detection in
Sceloporus undulatus lizards
Visual signal properties often vary greatly between and within individuals in a
variety of social contexts. For example, in many species of lizards, males
produce different complex motion displays used in territorial and courtship
contexts. While it is widely known that visual signals emitted by senders can
exhibit great variation in efficacy and design, far less is understood whether
and how receivers vary in the ability to detect and respond to different
complex signals. We tested for variation of signal detection within and
between receivers. Specifically, we tested whether Sceloporus undulatus
lizards exhibit differential signal detection between the left and right visual
fields, a phenomenon known as visual laterality. Additionally, we tested
whether male and female S. undulatus lizards differ in their ability to detect
two types of motion signals displayed by males: courtship and territorial.
Using a robotic lizard model, we assayed visual performance from each
visual field and each sex by measuring the latency to detect the two male
display types. While signal efficacy can greatly depend on the receivers
ability to detect and respond to a senders signals, variation both within and
between different receivers can affect the direction of signal evolution. We
found that the left and right visual fields of both males and females differ in
detection performance for both display types. Detailed results and data will
be presented. Our findings suggest that sexual asymmetry and laterality of
visual ability may play an important role in the evolution of visual
communication systems and should be taken into consideration when
studying signal design and efficacy.
P2.107 MORGAN, M*; CARRIER, D; University of Utah, Salt Lake City;
[email protected]
The evolution of the human hand: making a fist.
Anatomical features that distinguish human hands from the hands of other
apes undoubtedly facilitate our ability to make and use tools. However, the
high proclivity of our species for aggression led us to suspect that the
anatomical configuration of our hands may also protect the hand from injury
when striking an opponent. Relative to other apes, humans have shorter
fingers (digits 2-5) and a thumb (digit 1) that is much larger, more mobile and
muscular. These changes allow humans to form a fist in which digits 2-4 are
firmly buttressed by contact of the fingertips against the palm and by the
wrapping of the thumb around the distal phalanges of digits 2, 3 and 4. We
suggest that this buttressing provides greater stiffness at the
metacarpal-phalangeal and phalangeal-phalangeal joints, and thereby
protects the fist from injury when delivering a blow. The importance of
buttressing may be found in a common injury called the Brawlers Fracture,
which is characterized by fractures of the necks of the relatively
un-buttressed 4th and/or 5th metacarpals. To test the hypothesis, that the
proportions of the human hand provides protection against injury during
fighting, we measured the stiffness of the 2nd metacarpal-phalangeal joint in
a closed fist using a force transducer and a linear transducer. Subjects used
three different fist postures: full buttressing, no thumb buttressing, and no
buttressing. Results confirm that the buttressing inherent in a formed fist
increases the stiffness of the metacarpal-phalangeal joints. On average, the
no thumb posture exhibited approximately 1/2 the stiffness of a fully
buttressed fist and the no buttressing posture exhibited 1/3 the stiffness of a
fully buttressed fist. These results are consistent with the idea that the
selection for aggressive behavior played a role the evolution of the human
hand.
P3.48 MORRILL, Matthew*; BRONIKOWSKI, Anne; Iowa State University;
[email protected]
Evolution of Life Histories in Garter Snakes: Correlations among
Performance, Morphology, and Behavior
Performance has been shown to be strongly correlated with fitness in
reptiles, including garter snakes, and performance measures early in life
reflect later trends. Anti-predator behavior and pattern morphology have
been shown to be strongly correlated with each other and with fitness. We
measured performance, anti-predator behaviors, and dorsal patterning in
lab-reared juveniles from closely-related populations of western terrestrial
garter snake, T. elegans, representing two life history ecotypes. High
elevation, meadow (M-slow) snakes grow slow, mature late, and live long
(median lifespan 8 yrs), and low elevation, lakeshore (L-fast) snakes grow
fast, mature early, and die young (median lifespan = 4). In addition, the two
ecotypes have been shown to differ across a suite of other traits. The
purpose of this study was to determine if the two ecotypes differed in traits
related to predator avoidance to ask what are the ecological forces
underpinning the evolution of anti-predator characters. Dorsal pattern was
strongly correlated to ecotype with L-fast snakes being more patterned (i.e.
checkered or spotted) and M-slow snakes being generally solid. Both
performance and reversal behaviors were influenced by ecotype: L-fast
snakes were faster and reversed less than M-slow snakes. Stopping
behavior (coiling) was not influenced by ecotype, pattern, or sex. We discuss
these results in the context of the ecology and evolutionary history of
lakeshore and meadow populations.
P3.23 MORTENSEN, J.L*; CURRY, R.L; Villanova University;
[email protected]
Conservation ecology and social organization of the White-breasted
Thrasher on St. Lucia
The White-breasted Thrasher Ramphocinclus brachyurus is an endangered
songbird endemic to the islands of St. Lucia and Martinique. Research in
2002-2004 established that the population comprises ca. 600 breeding pairs,
80% of which inhabit dry forest along the east coast of St. Lucia in two
subpopulations. This work also revealed that the thrasher is a facultative
cooperative breeder. The Praslin subpopulation is now facing an immediate
threat: a resort under construction will destroy or fragment habitat containing
up to 35% of the global thrasher population. Here we examine the effects of
habitat loss associated with resort construction on White-breasted Thrasher
reproductive success and social ecology. Mayfield nest success estimates
did not differ between the pre (2002-04) and post-disturbance (2006-07)
periods. From 2006 to 2007, nest success remained the same within
fragments (27 fragments, 0.02-20 ha) and decreased in the resort nature
reserve (26 ha plot bordering contiguous forest); edge nests were more
successful than those in the interior. Group size and the proportion of groups
cooperatively breeding increased significantly from 2002-04 to 2006-07,
though we did not see any evidence of displaced birds joining previously
established territories, as was predicted. This research advances
understanding of how indirect mechanisms may magnify overall impacts of
habitat loss, determines the degree of site fidelity of thrashers living in
fragments on the development site and the effects of fragments on their
tendency to maintain territories and group stability, and will influence future
decisions about habitat protection on St. Lucia.
e278
P1.148 MOSKALIK, Christine/L.*; BUCHHOLZ, Daniel/R.; University of
Cincinnati; [email protected]
Two cytosolic thyroid-hormone binding proteins (CTHBPs) show
tissue-specific mRNA expression patterns across organs throughout
frog metamorphosis
Thyroid hormone (TH) plays an integral role in the growth and development
of all vertebrates and also influences reproduction and metabolism.
Amphibians are a good vertebrate model to study TH signaling because
tadpole development is independent of the mother and metamorphosis is
totally dependent on TH. Metamorphosis proceeds in an asynchronous
fashion (i.e. intestine remodels after limbs but before tail) which is likely due
to differential organ/tissue-sensitivity to the TH signal. In vitro studies of TH
signaling have identified various cytoplasmic proteins influencing the TH
signal during development. It has been suggested that one such protein, a
cytosolic thyroid-hormone binding protein (CTHBP), modulates cellular
concentrations of free TH; when TH is bound by a CTHBP in the cytoplasm it
is unable to enter the nucleus and facilitate transcription of TH-response
genes. This research aims to quantify the mRNA expression levels of two
known CTHBPs, ALDH1 and PKM2, in various Xenopus tropicalis organs
collected at different developmental stages, using quantitative PCR.
Preliminary data show high mRNA expression levels of ALDH1 in organs
before and after, but not during active remodeling, whereas PKM2 shows a
less obvious expression pattern in some of the organs weve examined.
Results from this research provide additional support for CTHBP's role in TH
signaling during amphibian development as well as mechanistic insights
toward understanding organ/tissue-sensitivity to TH in vertebrate
development.
P2.54 MOSTAFIZ, W.; GIDMARK, N.*; SWARTZ, S.; Harvard School of
Dental Medicine, Brown University; [email protected]
Histology and Morphology of Cyprinid Pharyngeal Dentition in Relation
to Diet
Many characteristics define the dietary habits and functions of a particular
species. Furthermore, the underlying functional bases of the ability to detect,
pursue, capture, and to successfully handle prey may relate directly to
morphology (Wainwright, 1988). Most studies focus on oral teeth and their
relation to diet and dentition, while few studies consider the properties of
pharyngeal teeth and also consider their dietary function. In particular,
specialized cusps are one essential aspect of tooth shape that relates to
wear. Cuspal wear correlates with the direction of masticatory movements
and forces and exhibits the thicker enamel layers. This suggests that the
cusps themselves are functionally adapted to masticate food, which enables
teeth to withstand the usual stresses of mastication (Luke and Lucas, 1983).
It has been hypothesized that evolutionary shifts to morphologies associated
with herbivory, particularly flattened cusps, occurred simultaneously in
multiple cyprinid lineages (Gidmark and Simons, in prep). We examined the
morphological and histological features of species in the Erimystax and
Pimephales clades, members of the Cyprinidae. Cross-sections of the cusps
were stained and imaged, and scanning electron microscopy images of
whole tooth rows were obtained. With regard to evolutionary influences,
observational data were incorporated into and analyzed with consideration
for each clade's established phylogenetic tree. Herbivorous taxa exhibited
modified cusps that were worn, flattened, and possessed an additional layer
of tissue. Meanwhile, all carnivorous taxa had one tissue layer and were
morphologically diverse. Carnivorous Pimephales taxa exhibited concave
cusp bodies. These characteristics in cyprinid fishes support a strong
correlation between herbivorous diets and functional morphological and
histological adaptations.
P2.124 MUIR, TJ*; COSTANZO, JP; LEE JR, RE; Miami University;
[email protected]
A Comparative Study of Urea-Induced Hypometabolism in Ectothermic
Animals
Many organisms endure extended periods of dormancy by depressing their
metabolism, effectively prolonging their endogenous energy-stores. Though
the mechanisms of hypometabolism are incompletely understood, recent
evidence suggests that urea accumulation in autumn and early winter
reduces metabolism by 25% in hibernating wood frogs (Rana sylvatica).
Moreover, metabolic rates of isolated tissues were reduced by 50% in
skeletal muscle and 20% in liver when they were tested in the presence of
urea. In addition to R. sylvatica, species from several taxa accumulate urea
during extended dormancy and may benefit from its putative hypometabolic
effect. To investigate the phylogenetic breadth of the hypometabolic
response to urea, we studied four animals that accumulate urea during
dormancy from the clades Amphibia (Scaphiopus bombifrons and
Ambystoma tigrinum), Reptilia (Malaclemys terrapin), and Mollusca
(Anguispira alternata). Rana pipiens, a close relative of R. sylvatica that does
not accumulate urea during hibernation, was used to shed light on whether
urea-induced metabolic depression was exclusive to urea accumulators. For
each animal, we measured rates of oxygen consumption of isolated tissues
in the presence or absence of physiological concentrations of urea. Tissues
from some species had reduced metabolic rates in the presence of urea,
whereas those from other species showed no effect. Our results suggest that
the urea-induced hypometabolism initially discovered in R. sylvatica is
present in at least some tissues of other animals that accumulate urea during
dormancy. Lastly, urea did not affect metabolism of tissues from R. pipiens,
suggesting that R. sylvatica and other urea-accumulators may have
specially-adapted metabolic machinery that is particularly susceptible to
perturbation by urea. Supported in part by NSF grant IAB 0416750.
P2.61 MULLER, UK*; WASIM, A; FONTAINE, E; LENTINK, D;
KRANENBARG, S; SCHULTE-MERKER, S; VAN LEEUWEN, JL; California
State University, Wageningen University, California Institute of Technology,
Hubrecht Institute; [email protected]
Increased body-axial stiffness reduces escape performance in larval
zebrafish
Fish larvae swim by undulating their body. The shape of their body wave
depends on the interaction between their body and the surrounding water.
This study focuses on zebrafish, in particular the comparison between
wild-type and a mutant called stocksteif. This mutant shows severe
over-ossification of the entire notochord, causing the vertebrae to fuse into a
stiff rod over the first 15 days of larval development. By comparing wild-type
and stocksteif morphs, we studied how stiffening the vertebral column affects
the shape of the body wave, and how this change in body wave kinematics in
turn affects escape performance in zebrafish larvae. We recorded escape
responses from a top view with a high-speed camera at 1500 frames per
second to determine swimming kinematics. At age 5 days, that is before the
vertebral column shows significant ossification, the two morphs body wave
kinematics and escape performance are not significantly different. At age 15
days, the vertebral column of the stocksteifmutant is largely fused. We found
that as ossification of the axial skeleton progresses, body wave speed and
peak curvature decrease in the stocksteifmutant, but not the wildtype with
unfused vertebrae. Both body wave parameters affect the larvas escape
performance: stocksteif larvae achieve lower translational accelerations. The
increasing stiffness of the vertebral column seems to seriously limit the axial
muscles ability to bend and undulate the fishs body.
e279
P1.58 MULVANY, S.L.*; MOTTA, P.J.; Univ. of South Florida, Tampa;
[email protected]
Feeding kinematics of the Atlantic stingray (Dasyatis sabina) and
yellow stingray (Urobatis jamaicensis).
Many batoids utilize their body to pin benthic organisms against the substrate
during feeding. While this general prey capture technique is well known, it is
not known if there are any kinematic differences in prey capture and feeding
among different batoids. Nor is it known if batoids are able to modulate
feeding behavior with different prey types. This study compares the feeding
kinematics of two batoids, Dasyatis sabina and Urobatis jamaicensis, using
live and dead prey. A series of kinematic variables relating to prey capture
and manipulation were quantified. Ten feeding events were captured per
animal, per treatment. All rays exhibited a general feeding behavior of
swimming over the prey and forming a tent around the prey with their anterior
pectoral fin margin, trapping and repositioning the prey between the
substrate and the ray's body. Once near the mouth, the rays would use
suction and biting to capture and ingest prey. Preliminary results indicate D.
sabina is faster at tenting and repositioning prey. However, there is no
difference in the duration of bite between D. sabina and U. jamaicensis, but
both species modulate feeding behavior depending upon prey type. Duration
of bite does not change with different prey types, but all other durational
variables increase with live elusive prey for both species. While locomotion is
generally thought to be the primary function of the pectoral fins, the pectoral
fins play a key role in prey capture for D. sabina and U. jamaicensis.
P2.163 MUNRO, H.*; BONIER, F; LOCKHART, L; MOORE, I;
ROBERTSON, R.J.; Queen's University, Kingston, ON, Virginia Tech,
Blacksburg; [email protected]
Hormones and life-history trade-offs: how do parental corticosteroid
levels correlate with changes in offspring sex ratio in tree swallows
(Tachycineta bicolour)?
Species face many trade offs as a result of resource availability, time, and
physical constraints. These trade-offs often manifest themselves in
modifications of life-history traits that may be mediated by hormonal signals.
Corticosterone (cort), a hormone involved in metabolic function as well as
response to stress, may influence these trade offs. Offspring sex ratio
biasing in many avian species, including tree swallows (Tachycineta
bicolour), has received attention in past years. While occurrence of sex ratio
biasing is well documented, the mechanisms underlying this phenomenon
remain unknown. Previous studies have suggested a causal relationship
between cort and sex ratio biasing. We looked at the relationship between
offspring sex ratio in tree swallows and parental baseline cort levels in a
box-nesting population at Queens University Biological Station in Ontario,
Canada. We will relate both social male and female cort levels to sex ratio of
their offspring. We expect that parents with higher cort levels will have
female-biased clutches while parents with lower cort levels will have
male-biased clutches. A finding of a natural correlation between parental cort
levels and offspring sex ratio will provide further support of the potential
causal link between cort and sex ratio biasing in birds.
P1.129 MURRAY, S.*; PERDOMO, Y.; CARROLL, M.A.; CATAPANE, E.J.;
Kingsborough Community College, Medgar Evers College;
[email protected]
Effects of Chelating Agents on Manganese Accumulations in Gill of the
Eastern Oyster, Crassostrea virginica
Manganese (Mn)is needed in small amounts for normal physiological
functions, but high amounts are toxic and causes Manganism. Manganism
has been misdiagnosed as Parkinsons disease. The two are similar and due
to disruptions in dopamine neurons in the brain. Recently, p-aminosalicylic
acid (PAS) has been used to alleviate symptoms of Manganism. PAS has
anti-inflammatory and chelating properties. The ability of PAS to ameliorate
symptoms of Manganism is postulated to be related to its chelating actions.
Crassostrea virginica, possesses a dopaminergic system innervating its gill.
Our lab showed manganese disrupts this dopaminergic innervation. We also
found PAS caused a dose dependant decrease in Mn accumulations in
oyster gill. This study sought to determine if other chelating agents caused
similar reductions in Mn accumulations as PAS. We incubated gills of C.
virginica, for 10 hour with 500 µM of Mn, followed by 3 day treatments with
up to 2 mM of the metal chelators, diaminocyclohexanetetraacetic acid
(DACH), sodium EDTA (EDTAna) or calcium EDTA (EDTAca). Mn levels
were measured using a Perkin Elmer AA800 Atomic Absorption
spectrophotometer with a THGA graphite furnace. All 3 chelating agents
reduced Mn accumulations compared to controls. DACH was the most
effective, followed by EDTAca and EDTAna. The study shows the chelating
agents are effective in reducing Mn accumulations and supports the
hypothesis that the mechanism of action of PAS in treatment of Manganism
is related to its chelating abilities. This work was supported in part by the
Louis Stoke Alliance for Minority Participation (LSAMP) in Science, and by
grants 2R25GM06003-05 of the Bridge Program of NIGMS, 0516041071 of
NYSDOE, 0622197 of the DUE Program of NSF, and 0420359 of the MRI
Program of NSF.
P3.210 MURRAY, I.W.*; SMITH, F.A.; Univ. of New Mexico, Albuquerque;
[email protected]
Life in an extreme environment: The effects of heat on foraging and
survival of woodrats (Neotoma) in Death Valley, California
Death Valley, CA is one of the hottest and driest environments on Earth, with
summer temperatures routinely exceeding 50°C. Living in such extreme
thermal conditions undoubtedly poses unique selective pressures on
organisms, yet a number of vertebrate species are found in the hottest
habitats at -84m below sea level. One of these is the Desert woodrat
(Neotoma lepida), a small (80-200g), herbivorous murid rodent that occurs in
remarkably high densities on these sites. The presence of this animal is
particularly surprising because it lacks any sort of specialized adaptation to
heat, and moreover, has a lethal upper critical temperature of 42°C. Here,
we report on studies examining how these woodrats survive and prosper in a
habitat where ambient temperatures regularly exceed lethal maximums
(42°C) for weeks at a time. By using small temperature data-loggers
(Thermochron iButtons) attached to rat collars, we characterize the daily
activity budget and foraging ecology of these animals in the context of the
thermal environment. We find that: 1) movement patterns are tightly
constrained by temperature, 2) animals regulate movement to minimize
exposure to potential lethal temperatures, and 3) there are seasonal patterns
to foraging behavior. We gain important insights into cryptic components of
woodrat biology with the aid of iButtons.
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P3.117 NADELSON, LS; WALTERS, LJ; WATERMAN, JM; SACKS, P*;
Boise State University, University of Central Florida;
[email protected]
What works best? Classroom undergraduate research experiences with
different levels of inquiry
Financial constraints and increasing numbers of undergraduates interested
in research impact opportunities for one-on-one work with faculty mentors.
To increase access to undergraduate research (UR) opportunities, three
traditional lecture courses were selected for integration of different
approaches to UR: 1) ClassGuided Research Experience in which students
are required to develop testable hypotheses and carry-out research on any
topic that fits within the scope of the course; 2) Faculty-Guided Research
Experience in which faculty embeds students into their on-going research;
and 3) Mixed Faculty/Class Research Experience in which students select
from a list of testable hypotheses compiled by faculty who also provides the
basics, but not the details, for experimental design. Funded by the UCF
CASTL Program, we assessed student perceptions of their class UR
experiences. While comparison of our three classes was complicated by
course objectives, sample size, and location (one was study-abroad), overall
the data showed all students involved in classroom UR felt it was a good way
to learn science and positively impacted their interest in science. Student
responses to the three approaches however differed significantly, with the
perceived greatest gains in learning detected in those involved in a
class-guided research experience (ANOVA: p < 0.01).
P3.51 NAUWELAERTS, S*; MALONE, S; CLAYTON, HM; Michigan State
University, East Lansing; [email protected]
Development of postural stability in horses from newborn to one month
old.
Motor control development is the sequential, continuous age-related process
whereby neurological control of skilled and coordinated movements changes.
The process involves changes in coordination of locomotion, development of
strength, posture control, balance, and perceptual skills. Young horses are
able to stand within hours after birth despite their relatively small muscle
mass and immature motor control. This study analyzes the development of
motor control in foals using Postural Sway Analysis (PSA). When a horse is
standing stationary, gravity is counter-acted by the net ground reaction
forces under each hoof. The location of the net upward force, the center of
pressure (COP), can be measured using a force plate. PSA tracks
movements of the COP over a period of time. In this study, PSA was
performed immediately after newborn foals nursed for the first time
(approximately 2 hours after birth), daily for a week, and once weekly until
the foals reached one month of age. Three measurements of postural sway
were used: amplitude of sway in both craniocaudal and mediolateral
directions, mean sway velocities, and mean frequency after fast fourier
transformation. Static balance improved rapidly. Static instability was greater
in the craniocaudal direction than in the mediolateral direction, which is the
opposite of what is observed in adults. Sway amplitudes decreased during
the first 5-7 days after birth. Velocities and frequencies continued to
decrease during the first 3 weeks post-partum. There was considerable
inter-individual variation between foals that could partly be linked to
differences in conformation and morphology. This study is part of a larger
project that will look at development of both static and dynamic stability. We
will continue to follow the foals through one year of age.
P1.100 NAVA, S. S.; Indiana University and the Center for the Integrative
Study of Animal Behavior; [email protected]
Population Divergence and Sexual Asymmetry of Visual Performance in
Sceloporus undulatus Lizards at the White Sands Ecotone.
In animal communication, the sensory drive model predicts that visual
signals evolve to match the visual abilities of receivers, which in turn are
shaped by the physical conditions of the environment. Thus, when
populations of animals live in habitats that differ in visual conditions, the
visual systems of individuals from those populations may diverge, and in turn
guide the coevolution of signals and visual performance. This coevolution
may also depend on the strength of differential selection on the sexes, e.g., if
sexual selection acts strongly and independently on both sexes, phenotypic
evolution can be accelerated. When the sexes have been subjected to
different selective pressures, they may not only be sexually-dimorphic in
phenotype, but also in the underlying genetic, morphological, and
physiological mechanisms that produce those phenotypes. Different
mechanisms are likely to yield different adaptive responses to subsequent
selective pressures and hence slow or accelerate the sensory drive process
and its effect on population divergence and evolution. Here, I tested for
population and sex differences in visual performance in the sexually
dimorphic Sceloporus undulatus lizards that have evolved adaptive dorsal
coloration in three extremely divergent habitat types (white sand dunes,
black lava rocks, and desert scrub). I show that morphs from the three
habitats differ in spectral sensitivity to the blue color exhibited by males. I
also find that males and females differ in their ability to detect the blue color.
Specific data and results will be presented. These findings suggest that
visual performance may evolve quickly and diverge between the sexes and
that the sensory drive process may be best described as the repeated
co-evolution between signals and receiver sensory systems.
P2.185 NEBEKER, CA*; SKOPEC, MM; HALEY, S; DEARING, MD; Weber
State University, University of Utah, University of Utah; [email protected]
Quantification of biotransformation enzymes implicated in Neotoma
lepida's ability to consume creoste
Two populations of the desert woodrat (Neotoma lepida) have different
tolerances for creosote bush (Larrea tridentata). Very few animals consume
creosote bush since the leaves are coated with a toxic phenolic resin
deterring herbivory. However, a population of the desert woodrat from the
Mojave Desert consumes creosote as a large part of its diet; leading us to
believe it has evolved a superior ability to biotransform the resin present on
creosote bush when compared to a population of the desert woodrat from the
Great Basin desert where creosote bush is absent. A previous study in the
lab showed that the Mojave woodrats have higher activity of two
detoxification enzymes glutathione s-transferase (GST) and cytochrome
P450 2B (CYP2B) compared to Great Basin woodrats when fed a diet
containing creosote resin as well as a control diet. We quantified the amount
of enzyme present using western blots,and found that similar to enzyme
activity, there was a trend for GST protein levels to be higher in the Mojave
woodrats than the Great Basin woodrats when fed a diet containing creosote
resin as well as a control diet (F3,20=2.363 p=0.102). For CYP2B however,
their was no difference in the amount of protein between the two populations
(F3,20=0.225 p=0.878) . This leads us to assume the Mojave population has
evolved a new isoform of CYP2B that is more effective and therefore has
higher activity per unit protein. Our next step is to compare the gene
sequences for CYP2B in both populations to determine if they differ in a
manner that could lead to functional differences.
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P1.133 NELSON, M.*; CARROLL, M.A.; CATAPANE, E.J.; Medgar Evers
College; [email protected]
Effects of p-Aminosalicylic Acid on the Neurotoxic Effects of
Manganese on the Dopaminergic Innervation of the Gill of the Bivalve
Mollusc, Crassostrea virginica
Lateral cilia of the gill of Crassostrea virginicaare controlled by a reciprocal
serotonergic-dopaminergic innervation from their ganglia. Serotonin is an
excitatory neurotransmitter at the ganglia and gill, causing cilio-excitation.
Dopamine is an excitatory neurotransmitter in the ganglia, but an inhibitory
neurotransmitter at the gill, causing cilio-inhibition. Manganese (Mn) is a
neurotoxin causing Manganism in people chronically exposed to elevated
levels in their environment. Clinical interventions for Manganism have not
been successful. Recently, p-aminosalicylic acid (PAS) is providing effective
treatment of severe Manganism in humans. PAS has anti-inflammatory and
chelating properties. The mechanism of action is unknown and further
studies of PAS in the treatment of Manganese is necessary. Previously, we
showed short-term treatments of C. virginica with Mn disrupts the
dopaminergic innervation of the gill. In this study we examined acute effects
of PAS, EDTA and the anti-inflammatory agent, salicylic acid (SA) on the
effects of Mn on gill innervation. Beating rates of lateral cilia in gill epithelial
cells were measured by stroboscopic microscopy of gill preparations which
had the ipsilateral visceral ganglia (VG) attached. The cerebrovisceral
connective innervating the VG were stimulated using suction electrodes,
before and after additions of PAS, EDTA and SA to the gill. PAS and EDTA
effectively blocked the neurotoxic effects of Mn, while SA did not. The study
demonstrates that the mechanism of action of PAS in alleviating Manganism
in humans may be more related to its chelating abilities as opposed to its
anti-inflammatory actions. This work was supported in part by grants
2R25GM06003-05 of the Bridge Program of NIGMS, 0516041071 of
NYSDOE, and 0622197 of the DUE Program of NSF.
P2.85 NEUFELD, Chris J.*; EDGELL, Tim C.; University of Alberta;
[email protected]
The role of shifting detection thresholds and associative learning
determine prey responses to the European green crab on the west
coast of North America
Rapid population-wide changes in the ability of prey to detect novel predators
are common in marine systems. Many authors conclude that these changes
have resulted from rapid evolution of chemical cue recognition. However, an
alternative hypothesis - that changes in cue recognition result from
within-individual plasticity, mediated by cue sensitivity or associative learning
- has not been tested. In the northeast Pacific, the recent arrival of the
European green crab, Carcinus maenas, offers an opportunity to study the
mechanisms used by prey to recognize and respond to novel predators. On
the Pacific coast, the intertidal whelk Nucella lamellosa thickens its shell
when exposed to effluent of the crab Cancer productus or damaged
conspecifics; however when native whelks are exposed to the effluent of the
introduced European green crab, no shell-thickening occurs. To investigate
the role of within-individual changes in cue recognition, whelks were
conditioned through exposure to water containing chemical cues from either
the novel C. maenas or the familiar C. productus feeding on damaged
conspecifics; control groups were exposed to effluent of C. maenas, C.
productus, or seawater alone. This phase was followed by a one-month
phase where whelks were exposed to effluent of C. maenas or C. productus
alone. Whelks exposed to effluent of both the novel and familiar crab
predator feeding on conspecifics grew more predator-resistant shells relative
to controls when subsequently exposed to effluent from C. maenas. This
suggests that shifting detection thresholds or increased fearfulness to novel
stimuli may mediate whelk responses to novel predators. These types of
responses have the potential to act on entire populations and thus may play
a crucial role following the arrival of a novel predator.
P3.33 NEWEL, M.S.; MARTIN, K.M.F.; BOURNE, G.B.*; University of
Calgary, Alberta, Canada; [email protected]
Observations on the functional morphology of the Pacific geoduck
clam, Panopea abrupta (Conrad, 1849)
Reports suggest that the Pacific geoduck, Panopea abrupta, is the largest
and most long-lived burrowing clam in the world. Although this species is the
target of an important commercial fishery and growing aquaculture efforts,
many aspects of their basic biology remain undescribed. We combined
observations of the behaviour of captive specimens, with a series of
dissections and a three-dimensional computer reconstruction of the entire
animal, as well as select isolated anatomical features, to illustrate aspects of
their functional morphology. Within the fused mantle cavity of the geoduck,
the anterior portion contains a large, globose visceral mass, a set of paired,
robust labial palps and a reduced foot that functions as a plunger that pushes
any accumulated detritus out the pedal aperture. The posterior portion of the
mantle cavity is dominated by the infra- and suprabranchial chambers,
separated by a comparatively small ctenidium, and dorsally a relatively
inconspicuous heart/kidney complex located beneath elements of the hinge.
Undoubtedly the most prominent element of geoduck morphology is the
extremely large, muscular and completely fused siphons, which has
previously been purported to be capable of generating considerable water
pressures and flow rates. In addition, we observed that captive geoducks
gain leverage from the siphon and move about a bare aquarium. This may
provide a mechanism for at least limited postural and positional mobility in
their natural habitat, as compensation for their reduced foot. Finally, we
believe that a comprehensive description of the functional morphology of P.
abrupta will lay the foundation for subsequent research into the biology of
these fascinating and increasingly economically valuable animals.
P2.121 NICHOLS, KS*; ERICKSON, PA; MAUCK, RA; WHEELWRIGHT,
NT; Bowdoin College, Kenyon College; [email protected]
Surf and turf: foraging choices of an island sparrow population
Foraging choices of parents feeding nestlings play an important role in
offspring survival and quality. Different prey items can affect nestling growth
and development. Savannah Sparrows (Passerculus sandwichensis)
breeding on Kent Island, New Brunswick, Canada forage in both terrestrial
(field and forest) and intertidal habitats during the breeding season. Analysis
of 13C, a stable isotope of carbon, can quantitatively describe differences in
foraging choice within and between populations. Differential uptake of 13C
between terrestrial and aquatic photosynthesis allows for the determination
of the percentage of an organisms diet that comes from terrestrial or aquatic
sources. We used stable isotope analysis of blood and feather samples of
adults and nestlings, visual observations of nests, and monitoring of nestling
weight to determine whether different foraging choices by parents affected
offspring growth. We observed 26 nests for an average of 2 hours each
during which time identity of parent, direction of approach, food size and
type, and habitat where foraging occurred was recorded for each visit to the
nest. Preliminary analysis of the observational data suggests that at some
nests parents forage preferentially from one direction while other parents
forage randomly in relation to direction. Once stable isotope samples are
analyzed, we will test how foraging behavior and diet choice influence
offspring quality in P. sandwichensis in an island ecosystem.
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P3.22 NUNEZ, CMV*; ADELMAN, JS; MASON, C; RUBENSTEIN, DI;
Princeton University, Foundation for Shackleford Horses, Inc.;
[email protected]
Behavioral effects of contraception management; the use of porcine
zona pellucida on wild horses
The behavioral effects of the immunocontraceptive agent porcine zona
pellucida (PZP) have not been adequately studied. Important managerial
decisions for several species, including the wild horse Equus caballus, have
been based on this limited research. We studied 25 horses on Shackleford
Banks, North Carolina to determine the effects of PZP contraception on
female fidelity to the harem male. We examined two classes of females:
contracepts, recipients of the PZP vaccine (n=17); and controls, females that
have never received PZP (n=8). We conducted the study during the
non-breeding season from December 2005 to February 2006, totaling 102.2
hours of observation. Contracepted mares changed groups more often than
control mares (P = 0.03), the number of group changes increasing with the
number of PZP applications (P = 0.01). In addition, contracepts visited more
harem groups than did control mares (P = 0.02), and exhibited more
reproductive interest (P = 0.01). Our study shows that the application of PZP
has significant consequences for the social behavior of Shackleford Banks
horses. In gregarious species such as the horse, PZP application may
disrupt social ties among individuals and inhibit normal social functioning at
the population level.
P2.153 O'BRIEN, S.*; MUKAI, M.; BENTLEY, G.E.; TSUTSUI, K.;
WINGFIELD, J.C.; University of Washington-Seattle, WA USA, University of
California-Davis, CA USA, University of California-Berkeley, CA USA,
Waseda University-Tokyo, Japan; [email protected]
Reproductive Profiles of Gonadotropin-inhibitory Hormone (GnIH) Gene
Expression in White-crowned Sparrows (Zonotrichia leucophrys)
Gonadotropin-inhibitory hormone (GnIH) is a recently discovered
hypothalamic neuropeptide found in a variety of vertebrates. In
white-crowned sparrows (WCSP) (Zonotrichia leucophrys), GnIH rapidly
inhibits plasma luteinizing hormone (LH) in castrates, as well as in intact,
gonadotropin-releasing hormone-treated birds, and in free-living WCSP with
naturally high plasma LH. GnIH shows seasonal changes in neuronal
attributes implying changes in storage and expression. Thus, we have
evidence for potential roles for GnIH in the timing of breeding. Via collection
and analysis of WCSP brain tissue, we investigate the changes in GnIH
expression throughout breeding and non-breeding reproductive paradigms.
We examine changes in GnIH expression through a variety of reproductive
treatments: 1) castration and testosterone implants to elucidate the role of
sex steroid feedback on the GnIH system. 2) GnIH mini-pump implants to
uncover the role of negative feedback. 3) Seasonal collections of brain tissue
to examine GnIH expression throughout the year. GnIH may play an
important part in the regulation of reproductive function and these expression
profiles may help to illuminate the ecological factors and reproductive
mechanisms that influence seasonal breeding.
P1.46 O'CONNOR, J.L.*; MCBRAYER, L.D.; ROSTAL, D.C.; Georgia
Southern Univ., Georgia Southern Univ. ; [email protected]
Effects of testosterone on bite force and locomotor performance in the
six-lined racerunner.
Numerous studies have examined the effects of testosterone on behavior in
territorial lizards, but few have explored the role of testosterone (T) in
non-territorial species. Here, we experimentally manipulated T levels in
Aspdidoscelis sexlineatus, a common non-territorial lizard. During the
breeding season, males exhibit mate guarding, and will follow a female for
several days after copulation. Male-to-male interactions during the breeding
season involve chasing and occasionally escalate into fights with biting.
Therefore, high bite force and high endurance capacity should be
advantageous to retain exclusive access to females and ensure paternity. In
territorial lizards, T levels peak with the breeding season and several studies
have cited T as a possible mediator of the seasonal increases in
performance (e.g. bite force and locomotor performance). Fluctuating T
levels have been observed in A. sexlineatus; however, the role that T plays
in the performance of A. sexlineatus or other mate guarding species remains
unknown. For this study, male racerunners were captured and blood
samples were drawn immediately to quantify T levels. Lizards were then
returned to the lab where locomotor performance (endurance), bite force,
and morphological data were collected. Following performance trials, lizards
received silastic T implants. Lizards were housed in the lab for four weeks
where locomotor endurance and bite force performance were measured
biweekly. Additionally, a blood sample was collected every two weeks to
monitor T levels. This research will quantify the morphological and
physiological factors affecting performance in A. sexlineatus and provide
valuable data concerning how T affects alternative mating systems.
P2.15 O'MALLEY, P. W.*; POPE, D. S.; Trinity University, Mount Holyoke
College; [email protected]
Male field crickets discriminate between pheromones of adult and
juvenile females
The field cricket, Gryllus texensis, uses pheromones for short range
communication. Previous work indicates male crickets show preference for
pheromones from females that had no previous contact with males. In this
study we examined the ability of male crickets to discriminate between male
and female pheromones and adult female and juvenile female pheromones.
Male crickets were isolated at least 3 days prior to testing. Half the males
were isolated after reaching final molt, so these males may have had sexual
encounters prior to testing. We collected pheromones on filter paper by
isolating the stimulus individuals in Petri dishes for 30 minutes. For each trial,
we placed a focal male in the test arena for 2 minutes of acclimation and
then presented him with two filter papers. Each male was presented with a
contrasting pair of pheromones, either male and adult female, or adult female
and juvenile female. For 10 minutes we recorded the time spent by the male
on the filter paper with active antennae or maxillary palpi movement. We
tested for differences in duration of time spent investigating the two pairs of
pheromones presented. We found no significant difference in the behavior of
virgin males and males that had been exposed to mature females as adults
and therefore grouped all males together for further analysis. Males overall
showed no significant difference in time spent investigating male and adult
female pheromones. However, when presented with juvenile and adult
female pheromones, males spent significantly more time investigating the
juvenile female pheromones. Male Gryllus texensis may be sensitive to
pheromonal cues of maturity since these may indicate how much previous
male contact the female has had, thus enabling males to allocate sperm to
virgin females and minimize sperm competition.
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P1.62 O'NEILL, M. W.*; GIBB, A. C.; Northern Arizona University;
[email protected]
Scraping and sucking: Does morphology determine performance in two
species of suckers?
The co-occurring desert and Sonora suckers show distinct morphological
and behavioral traits that yield predictions for feeding behavior. Desert
suckers have a broad mouth and a cartilaginous plate that appears
specialized for scraping attached algae, and Sonora suckers have a smaller
gape that may produce effective suction when capturing small invertebrates.
Gut content studies suggest that Sonora suckers feed more on insect prey
and desert suckers feed more on algae, and this is further supported by
stable isotope analysis, where Sonora suckers have a higher nitrogen signal
-- which indicates a higher proportion of animal tissue in the diet -- but both
species feed on algae and invertebrates. This raises the question: are
aspects of feeding behavior in each species modified to enhance
performance on particular prey items, perhaps reducing competition or
partitioning food resources? In the laboratory, we examine the performance
of each species on a variety of elusive and non-elusive prey types to answer
the following specific questions: (1) Are Sonora and desert suckers able to
capture the same prey items? (2) Are desert suckers more effective at
scraping algae? (3) Do Sonora suckers use suction when capturing insect
prey? Preliminary data for both species suggest that they will take prey on
the bottom, but not in the water column -- which suggests that only benthic
insects are likely to be included in the diet in the wild. Ongoing experiments
will examine the ability of each species to remove encrusting material from
the substrate by scraping and procure food from the substrate by suction.
P2.40 OBERG, F.*; HERNANDEZ, L. P.; George Washington University,
Washington, DC 20052; [email protected]
Untangling the palatal organ: Investigating the embryological origin of
a novel structure
Exploiting the conserved developmental mechanisms seen in vertebrates,
the zebrafish has become a popular model organism within the field of
biomedical research. Yet, by ignoring what makes this cypriniform fish
unique we are overlooking a powerful model organism for investigating the
origin and development of morphological novelty. The trophic diversity that
characterizes cypriniform fishes includes a unique feeding mechanism
whereby small food particles often encountered in benthic feeding are
extracted. The structure that plays a key role in separating edible from
inedible prey items during benthic feeding is the palatal organ. Located in the
anterior pharyngeal roof, the palatal organ is a muscular cushion composed
of a highly disorganized tangle of differently sized muscle fibers covered by
an epithelium studded with mucous cells. During feeding the palatal organ
secretes mucus to entrap food and the muscles work to entrap and move the
food along to the pharyngeal teeth. Functionally, and indeed even in
histological sections the palatal organ strongly resembles a small
mammalian tongue. There is little, if any, data addressing either the
embryological origin of this muscular organ or the ontogenetic stage at which
it first develops. Here we describe the ontogeny of the palatal organ in
several ontogenetic stages of the zebrafish. The palatal organ, while less
well-developed in zebrafish than in other cypriniforms, is apparent from very
early larval stages. Moreover, the combination of muscle fiber types seen in
the adult may reflect the complex embryological origin of this organ.
Identifying the developmental mechanisms responsible for the origin of this
feeding adaptation may enhance our understanding of how functional
novelties arise and evolve.
P3.49 OCOBOCK, Cara J*; PONTZER, Herman; MAKI, Julia; Washington
University in St. Louis; [email protected]
Modification of limb inertial properties leads to persistent changes in
neural control of walking in humans
Animals with distally heavy limbs, such as primates and felids, have been
proposed to use longer, slower strides to decrease leg-swing costs and
minimize locomotor energy use. In this study, we investigated whether such
cost-saving kinematic changes can be seen within a species when limb
inertial properties are altered, and whether long-term changes in limb inertial
properties produce persistent gait changes. Ten healthy human subjects
walked and ran on a treadmill under both a Control condition, subjects wore
a small weighted backpack, and a Leg Weights condition, subjects wore
ankle weights. Kinematics and oxygen consumption were measured in both
conditions; subjects then wore ankle weights for 6 hours, and oxygen use
and kinematics were measured again. For walking trials, results from
morning sessions indicated that subjects adapted immediately to a more
distally located limb center of mass by using lower stride frequencies.
Notably, results from afternoon walking sessions indicate that this change in
gait persisted once ankle weights were removed and subjects returned to a
normal, more proximally located limb center of mass. This persistence
suggests a change in the neural control of rhythmic locomotor patterns
brought about by experiencing a more distal hindlimb center of mass. There
was no reduction in stride frequency while running in response to wearing
ankle weights, suggesting that running is more resistant to kinematic
adjustment. For all trials, locomotor cost was similar between Control and
Leg Weights conditions. These results support the hypothesis that animals
with distally heavy limbs can maintain low walking costs through kinematic
adjustment, and suggest a feedback system in which locomotor control is
influenced by limb inertial properties.
P2.167 OKEKPE, CC*; NAVARA, KJ; HILL, GE; MENDONCA, MT; Auburn
Univ., Auburn Al, Univ. of Georgia, Athens Ga; [email protected]
Effect of diet on periovulatory levels of steroid hormones and primary
sex ratio in zebra finches
Recently, a number of studies on birds have indicated that females (the
heterogametic sex) are capable of using pre-ovulatory mechanisms to skew
primary offspring sex ratios; however, no one has conclusively identified the
mechanism responsible for this phenomenon. Sex is determined in the first
meiotic division when one sex chromosome is retained in the oocyte and the
other segregates to the polar body. During this time, follicular steroid
production is limited primarily to progesterone (P4) and it has been
suggested that maternal steroids, which are sensitive to environmental
perturbations, could influence sex chromosome segregation. Experimental
studies exploring the relationship of maternal steroids on sex ratio have
primarily administered various exogenous hormones but, to date, no one has
examined endogenous hormones at ovulation. We manipulated both diet
quality and perceived food availability in breeding female zebra finches to
examine the effects on natural levels of maternal steroids circulating during
meiosis I, the critical time in sex determination and primary offspring sex
ratio. We found that females on the low quality diet had significantly lower
body condition, but higher P4 and lower CORT levels when compared to
females on a higher quality diet. Levels of maternal testosterone do not differ
between diet quality or perceived availability. Though we do show an effect
of diet on body condition and levels of P4and CORT, factors which have
been shown to bias sex ratios, to date, this change in hormone profile at the
periovulatory period did not result in a change in the primary sex ratio in
clutches produced by females on the different diets.
e284
P3.211 OLSON, JR*; SWANSON, DL; COOPER, SJ; BRAUN, MJ;
WILLIAMS, JB; Ohio State Univ., Columbus, Univ. of South Dakota,
Vermillion, Univ. of Wisconsin-Oshkosh, Smithsonian Institution, Suitland,
MD; [email protected]
Metabolic performance and latitudinal distribution of Black-capped and
Carolina Chickadees
In endotherms, metabolic performance affects a wide array of ecological
traits, including species distribution, and researchers have suggested that
the northern boundaries of North American passerines are limited by birds
ability to sustain high metabolic rates required for thermoregulation.
Black-capped chickadees (Poecile atricapillus, BC) are year-round residents
in most of Canada and the northern United States, while Carolina chickadees
(Poecile carolinensis, CA) inhabit the southeastern United States. These
species hybridize along a narrow contact zone that is moving north at
approximately 1.6 km per decade, movement possibly facilitated by global
climate change. There is strong evidence that the chickadee hybrid zone is
correlated with temperature, as the east-west orientation closely matches
temperature isotherms. We measured basal (BMR) and peak metabolic rates
(PMR) for BC and CA in multiple states and also obtained metabolic rates for
additional populations in previously published studies. We noted a general
correlation between colder temperatures and higher metabolic rates among
populations of BC, although this trend was not robust between all locations.
Metabolic rates of CA did not differ between populations. Within Ohio, BMR
and PMR were significantly greater in BC than CA. However, metabolic rates
did not differ between the two species after controlling for the effect of mass.
Hybrids had a significantly higher mass-specific BMR than either parental
species. We suggest that the mtDNA-nDNA mismatch in hybrids may
produce defective metabolic proteins, increasing metabolic rate because
individuals rely on a greater rate of oxygen consumption to meet ATP
demands.
P2.91 OUFIERO, Christopher E.*; POLLUX, Bart J.A.; BANET, Amanda I.;
ARNOLD, Stephanie; GARLAND, JR, Theodore; Univ. of California,
Riverside; [email protected]
Does a primary sex character vary with the degree of female-biased
sexual size dimorphism: a test in the Poeciliidae.
Sexual selection has been recognized as a factor that shapes the evolution
of secondary sex characters, including aspects of morphology and behavior.
However, can sexual selection operate on primary sex characters? We
examined the relationship between female-biased sexual size dimorphism
(SSD, measured as male/female standard length) and length of the
gonopodium, a primary sexual character found in male poeciliid fish that is
used to inseminate the females. The Poeciliidae includes over 200 species of
freshwater, livebearing fish. Two main mating strategies occur in this family,
gonopodial thrusting and courtship. Species that exhibit gonopodial thrusting
exhibit few if any secondary sexual characters and a high degree of SSD;
whereas species that exhibit courtship tend to have secondary sexual
characters and a low degree of SSD. Therefore, it has been predicted that
species with a high degree of female-biased SSD should exhibit larger
gonopodia to aid in copulation. We tested this by examining SSD and
proportional gonopodium length (gondopodium length/male standard length)
in ~45 species of poeciliid fish in a phylogenetic context. We also examined
other relationships with SSD and gonopodia, such as allometry of the traits.
Preliminary non-phylogenetic results favor the prediction that species with a
high degree of SSD have proportionally longer gonopodia than those with a
low degree of SSD. Phylogenetically informed and additional results will also
be discussed. Supported by NSF DDIG IOS-0709788 to T.G. and C.E.O, and
NSF grant DEB-0416085.
P3.132 OZEL, L.D.*; CHANG, J.L.; Univ. of Miami, Coral Gables;
[email protected]
Differences in escape behavior between a cryptic and an aposematic
litter frog
Clay models have been used to investigate the relative anti-predator
effectiveness of cryptic and of aposematic coloration in litter frogs, but such
studies fail to account for possible differences in prey escape behavior. We
examined the escape behaviors of two litter frogs, the cryptic Craugastor
(=Eleutherodactylus) bransfordii and the brightly colored and toxic Oophaga
(=Dendrobates) pumilio, in response to a human predator. For all individuals,
we measured the distance between the frog and the observer at the instant
of flight (approach distance), and the distance between frogs initial and final
positions (retreat distance), in the field. The cryptic C. bransfordii had a
shorter approach distance than did non-calling individuals of the brightly
colored O. pumilio. In addition, we noted that calling O. pumilio males had a
shorter approach distance than did either non-calling male or female O.
pumilio. These findings demonstrate that a cryptic and an aposematic litter
frog differ in their escape response to a predator. These results also suggest
that, at least in male O. pumilio, a tradeoff may exist between predator
avoidance and reproductive success via territorial defense and mate
attraction.
P2.169 PAITZ, R.T.; BOWDEN, R.M.; CASTO, J.M.*; Illinois State Univ;
[email protected]
Embryonic modulation of yolk steroids in European starlings (Sturnus
vulgaris)
Sex steroids influence sexual differentiation during critical stages of
vertebrate embryonic development. In birds, steroids of maternal origin are
present in the yolk at oviposition and affect various aspects of offspring
development, but do not influence sexual differentiation. Steroids in bird egg
yolks decline markedly during early incubation via unknown mechanisms.
Our goal was to determine if embryos actively modulate yolk steroid signals
during early incubation. First, testosterone (T) and estradiol (E2) levels in yolk
and albumen of European starling eggs were characterized at oviposition.
Next, other eggs were incubated and yolk/albumen (YA) and whole embryo
homogenates were sampled throughout embryonic development to track
changes in progesterone (PROG), T, and E2 levels. Finally, tritiated T was
injected into eggs and radioactivity was measured in extracted organic and
aqueous fractions of both YA and embryo homegenates on embryonic day 6
(E6). Results indicate that at oviposition, T and E 2 occur in yolk but not
albumen, and yolk T concentration varies significantly among clutches.
Across development, E 2 remains low or undetectable, PROG and T
concentrations decline in YA homogenates, and are negatively correlated
with embryo mass. Presence of radioactivity in aqueous fractions of both YA
and embryo homogenates on E6 suggests that some tritiated T was
converted to a water-soluble form, the amount of which positively correlates
with embryo mass. Collectively the results indicate that starling embryos do
actively modulate yolk testosterone during early development via metabolism
of lipid-soluble steroid into a water-soluble metabolite. This steroid shunt
likely buffers embryos from the influence of yolk steroids during periods when
sexual differentiation could otherwise be influenced.
e285
P2.134 PAKALA, K/P*; BIGA, P/R; North Dakota State University;
[email protected]
Role of Matrix metalloproteinases in activating myostatin in the skeletal
muscle in response to high fat diet induced diabesity
High fat diet-induced obesity (HFDIO) is associated with type 2 diabetes and
metabolic dysfunction. Skeletal muscle and adipose tissue are the main sites
of energy utilization and play an important role in the regulation of energy
homeostasis. Obesity is also known to be a pro-inflammatory disease with
increased systemic cytokine release, potentially triggering local immune
responses. The intent of this project is to evaluate the relationship between
muscle growth, metabolism, and the immune system, specifically targeting
how matrix metalloproteinases (MMPs) and myostatin (MSTN) might interact
in skeletal muscle tissue. Myostatin is a negative regulator of skeletal muscle
mass and impacts body fat accumulation, and it has recently been
demonstrated that MSTN plays an important role in high-fat diet induced
obesity (HFDIO). Removal of MSTN results in resistance to HFDIO. In
addition, we have demonstrated that different strains of mice exhibiting
differential susceptibility to a high fat diet exhibit significant differential MSTN
gene expression. Also, MSTN appears to bind decorin in the ECM, which is a
target of MMP activity. Matrix metalloproteinases are zinc-dependent
endopeptidases and have been implicated in the pathology of
dystrophin-related muscle disorders and inflammatory myopathies. Activated
MMP-2 and -9 are present in muscle from obese mice, and MMP-2 gene
expression is highly upregulated in obese spleen tissue. MMP-9 gene
expression is elevated to a greater degree than MMP-2 in muscle tissue of
obese mice, suggesting a role of MMP-9 in muscle responses to
inflammation and possibly MSTN activation regulation. By comparing
different inbred strains of mice, we can better understand the genetic
components regulating diabesity, which may lead to a better understanding
of the interaction between the immune system and metabolism.
P2.125 PAN, Tien-Chien F.*; BURGGREN, Warren W.; Univ. of North Texas,
Denton; [email protected]
Cardiac, ventilatory and metabolic responses to hypoxia in developing
Xenopus laevis
Most research on the respiratory development of amphibians has focused on
metamorphosis rather than earlier stages when cardio-respiratory reflexes
are first appearing. The present study investigated early development of the
hypoxic responses under chronic normoxic (150 mmHg) and hypoxic (110
mmHg) conditions. The parameters measured here included gill and lung
ventilation, heart rate, stroke volume, cardiac output, mass-specific oxygen
consumption and critical PO 2 . Larvae started gill ventilation at 3 dpf and
began air-breathing at 4 dpf. For acute hypoxic responses, larvae developed
both hypoxic gill and lung hyperventilation at 5 dpf. Hypoxic tachycardia also
developed at 5 dpf and led to increased cardiac output. No differences in
stroke volume were observed. Mass-specific O 2 consumption decreased
following acute hypoxic exposure. Chronic exposure to hypoxia increased
both gill and lung ventilation frequency and the hyperventilatory responses to
hypoxia, but had no effect on cardiac responses. Hypoxic larvae also
exhibited lower O2 consumption than the normoxic group. Our results show
that ventilatory and cardiac reflex to acute hypoxia is established as early as
5 dpf. Higher ventilation frequency and enhanced hypoxic responses caused
by chronic hypoxia may be due to up-regulation of the O 2 -sensitive
chemoreceptors. The lack of significant changes in cardiac responses
between normoxic and hypoxic larvae suggests that O2 diffusion across the
respiratory surface is a major limiting factor in O 2 uptake. Metabolic
responses to hypoxia revealed that early larval Xenopus laevis as O 2
conformers.
P2.173 PARK, Sarah D.; ATHALE, Janhavi; NGUYEN, Thutrang T.; KANG,
Esther; CHEN, J.; CAMERON, J.S.*; Wellesley College, MA;
[email protected]
Acclimation to Hypoxia Alters Gene Expression and KATP Channel
Response to Acute Low Oxygen in the Hearts of Goldfish
Goldfish (Carassius auratus) are extremely tolerant of environmental hypoxia
and may retain normal cardiac function for several days in the complete
absence of oxygen. Previous results suggest that the hypoxia-induced
activation of cardiac ATP-sensitive potassium (KATP) channels, whether in
sarcolemmal or mitochondrial membranes, serves to increase tolerance of
low oxygen. We have characterized a nitric oxide (NO)- and
cGMP-dependent signaling pathway by which this KATP channel activation
occurs in acute hypoxia. The purpose of the present study was to resolve
alterations in cardiac cell viability, KATP channel activity and gene expression
in response to hypoxia acclimation. Goldfish were exposed to moderately
hypoxic conditions (2.6 mg O2/l) for seven days at 22oC. Isolated cardiac
myocytes from animals acclimated to hypoxia were significantly more
tolerant of subsequent exposure to acute hypoxia in vitro than were cells
from non-acclimated fish. The viability of cells from both groups was
decreased by the NO-synthase (NOS) inhibitor L-NAME and enhanced by
analogs of cGMP, although to different degrees. Quantitative real-time
RT-PCR data indicated that KCNJ11, a gene coding for the pore-forming
subunit of sarcolemmal KATP channels, was downregulated in response to
hypoxia acclimation, while the expression of HIF1α (hypoxia inducible factor)
was unchanged. These data indicate that prior whole-animal acclimation to
chronic environmental hypoxia enhances cellular tolerance of subsequent
low oxygen in this species, and suggest a role for the altered regulation of
cardiac K ATP channels in this response. (Supported by the Brachman
Hoffman Fund and by an HHMI grant to Wellesley College)
P2.8 PARKER, S.D.*; SEWALL, K.B.; HAHN, T.P.; University of California
Davis, University of North Carolina Chapel Hill; [email protected]
Heterospecific Vocal Mimicry in Cassin's Finch (Carpodacus cassinii)
Heterospecific vocal mimicry (HVM) is widespread among oscine songbirds.
In some cases songbirds mimic entire elements from other species
repertoires and use signals in the same social contexts. For example, studies
have established that HVM can function for deception of hosts by brood
parasites or predator evasion by eliciting mobbing behavior among
heterospecifics. In other cases, songbirds include mimicked elements in their
songs. It has been asserted that HVM in song is the outcome of passive
processes like the accumulation of learning mistakes to generate large
repertoires that include imitations. Alternatively, in other mimicking species,
HVM may be under sexual selection because females assess song
complexity as a cue for male quality. I investigated song complexity and
expression of HVM in Cassins finch (Carpodacus cassinii), a North American
mimicking species.
Cassins finch is an excellent model to test the sexual selection hypothesis
because males mimic many different species and insert those imitations in
songs used to attract females. My analysis of Cassins finch song reveals that
within a bout, males generate the greatest variation through manipulation of
heterospecific imitations in a single song theme. Further, these imitations are
placed at the end of songs, where the type and syntax of these elements
generate variation on the theme. These data suggest that Cassins finch
males control song complexity largely through appropriation of elements from
other species. Thus it is possible that sexual selection through female choice
is driving males to produce complex songs achieved through expression of
heterospecific imitations. This interpretation is consistent with the
observation that males seldom sing during aggressive encounters with other
males, but frequently do so when interacting with females.
e286
P2.63 PARSON, J.M.*; FISH, F.E.; NICASTRO, A.J.; West Chester Univ.;
[email protected]
Turning performance of batoid rays: Limitations of a rigid body
The ability to maneuver is critical to the locomotor performance of batoid
rays, but can be constrained by the inflexibility of the body. Turning motions
are therefore affected by the motions of the expanded and mobile pectoral
fins. Turning radius (maneuverability) and turning rate (agility) were
measured from overhead video recordings of rays in a large pool during
unrestricted swimming. The rays were characterized as swimming by
oscillatory movements of the pectoral fins (Aetobatus narinari, Myliobatis
freminvillii and Rhinoptera bonasus) or by undulations of the fins (Dasyatis
americana and Dasyatis centroura). Oscillatory rays maneuvered by either
powered or unpowered gliding turns, whereas undulatory rays turned using
asymmetrical undulations of both pectoral fins. Underwater observations
showed that both rays used banking while turning, which ranged from
15-70 o . No statistical differences were found between mean turning
parameters between the two locomotor types. However, minimum turn radius
and maximum turning rate were respectively smaller and larger for oscillatory
rays (0.7 m; 44.4o/s) compared to undulatory rays (1.0 m; 30.4o/s). Rays can
reduce the rotational inertia of the body by banking and bending the fins
dorsally to change the distribution of mass, thereby overcoming the
mechanical constraints on turning that are imposed by the structure of their
rigid bodies. Despite compensation by possessing flexible appendages, rays
still have lower agility compared to flexible-bodied swimmers.
P2.126 PATIL, Y.N.*; MENZE, M.A.; HAND, S.C.; Louisiana State University,
Baton Rouge; [email protected]
Arrest of aerobic metabolism in Artemia franciscana embryos during
diapause
Diapause embryos of the brine shrimp, Artemia franciscana, are
characterized by a low metabolic rate. Based on our previous data, we
hypothesized that metabolic arrest is due to a combination of at least two
mechanisms, namely substrate limitation to the mitochondrion and reversible
inhibition of oxidative phosphorylation. We measured metabolic
intermediates in metabolically-active embryos and in diapause embryos. A
significant reduction in glucose-6-phosphate was evident in diapause (0.22
+/- 0.02 nmol/mg embryo protein; mean SE, n = 3) versus active (1.85+/0.53 nmol/mg) embryos. Values for glucose in diapause (5.98 +/- 1.8
nmol/mg) and active (3.58 +/- 2.09 nmol/mg) embryos allow the calculation
of mass action ratios (0.04 diapause vs. 0.52 active), which indicate inhibition
at the hexokinase (HK) step and suggest a reduced glycolytic flux and
substrate limitation to the mitochondrion in diapause. Pyruvate is lower in
diapause (0.24 +/- 0.04 nmol/mg) than in active (0.46 +/- 0.08 nmol/mg)
embryos, but not as low as anticipated, despite being downstream of the
glycolytic inhibition at HK. This observation could be explained by an
inhibition of pyruvate dehydrogenase (PDH). Measurement of acetyl CoA
levels and kinetic characterization of PDH are underway to evaluate this
possibility. To further infer sites of respiratory inhibition, we measured the
apparent Km of Complex IV (cytochrome c oxidase) for cytochrome c (cyt c).
The value in diapause embryos (30.3 +/- 3.5 M; mean SE, n = 3) was
significantly higher than in active embryos (12.6 +/- 3.9 M). Whether or not
this reduction in apparent affinity has any impact on flux through Complex IV
depends on estimates of cyt c level in the intermembrane space. [Supported
by NIH grant 2 RO1 DK04670-14A1]
P1.137 PATTEN, S.B.*; NESTLER, J.R.; Walla Walla University, College
Place, WA; [email protected]
Detection and Localization of a Possible Photoreceptive Pigment in
Temperate Holothurians (Echinodermata)
Many echinoderms have the ability to detect light, either by primitive eyes or
through a diffuse dermal detection called extraocular photoreception.
Johnsen (1997) showed that an asteroid and an ophiuroid possibly contain a
rhodopsin-like protein that is likely used for photoreception. Many
holothurians have been shown to be photosensitive, but the cellular
mechanism and components used have not been described. The current
study was designed to determine if photosensitive temperate holothurians
have a rhodopsin-like protein that may be used for photoreception.
Photopigment protein was detected by western blotting using two
monoclonal antibodies raised against bovine rhodopsin (MW=39 kDa).
Pharyngeal retractor muscle taken from Cucumaria miniata during both
winter and summer show a solitary band at about 40 kDa. Tube feet (with
skin) and respiratory tree from C. miniata in summer also show a solitary
band at about 40 kDa. Oral tentacle and tube feet from Parastichopus
californicus have also shown solitary banding at about 40 kDa. Continuing
research is investigating two more species, Eupentacta quinquesemita and
Psolus chitonoides and determining the effect of light on photopigment
protein levels. The protein in question, which binds rhodopsin antibodies, is
in the molecular weight range of rhodopsins, and is found in photosensitive
holothurians, will be isolated and sequenced to determine if it is a
photoreceptive pigment.
P2.135 PATTERSON, J.P.*; BERNAL, D.; SEPULVEDA, C.; University of
Massachusetts Dartmouth, Pfleger Institute of Environmental Research;
[email protected]
A Comparative Study of the Capacity for Aerobic Metabolism in the
Locomotor Muscle of the Three Species of Thresher Shark (Family
Alopidae).
A recent study of the three species of thresher shark (Family Alopidae) has
revealed some striking interspecific differences in locomotor muscle
morphology. The common thresher (Alopias vulpinus) differs significantly in
the position of the red myotomal muscle (RM) when compared to the bigeye
(A. superciliosis) and the pelagic thresher (A. pelagicus), and is the only
species showing regional muscle endothermy. Due to the endothermic
nature of the common thresher, it is hypothesized that the locomotor muscle
of this species will have a higher capacity for aerobic metabolism at 20C
relative to the other two species. The purpose of this study was to compare
the activity of citrate synthase (CS; an index of aerobic capacity), and lactate
dehydrogenase (LDH; an index of anaerobic capacity) in the RM of three
species of thresher. Temperature readings were also taken in six longitudinal
positions along the body of the sharks, with a temperatures taken every
centimeter of probe penetration. Temperature readings for the common
thresher were above that of the ambient temperature at the depth caught,
while the pelagic and bigeye body temperatures were closer to that of the
ambient temperature at depth caught. The CS and LDH activity in the RM of
the common thresher at 20C was 2.4 and1.3 times higher respectively when
compared to the other two species. The average Q 10 between 15-25C
(1.65-CS, 1.64-LDH) in the common thresher did not differ significantly from
that of the pelagic and bigeye. These results indicate that although the
thermal effect on enzyme activity is similar, the overall activity of both these
enzymes in the RM is higher for the common thresher shark.
e287
P1.25 PATTI, A; HOCHBERG, R*; CLAMP, J; Univ. Massachusetts Lowell,
North Carolina Central Univ.; [email protected]
A novel peritrich (Ciliophora) from the symbiotic community of
freshwater pulmonate snails (Mollusca, Gastropoda) in Massachusetts
Freshwater pulmonates are host to numerous symbionts including
mutualistic, commensalistic and parasitic protozoans and metazoans. In our
investigation of the symbiotic community of two species of freshwater snails,
Menetus dilatatus and Physa sp., we discovered a previously undescribed
species of peritrich that lives inside the snails pulmonary cavity (lung). We
use a combination of brightfield, fluorescence and electron microscopy to
describe this new species. This ciliate, a member of the genus Scyphidia,
forms colonies on the mantle tissue of small snails with transparent shells.
The ciliate is host to endosymbiotic algae (presumably Chlorella) that
occupies a large proportion of the ciliates volume and forms a mixotrophic
relationship with it. As host snails age, their shells become less transparent,
and the colonial ciliate declines in abundance, indicating a potential obligate
relationship between the symbionts. Binary fission of the ciliates leads to the
production of swarmers that also contain endosymbiotic algae. This report
constitutes the first description of mixotrophy in Scyphidia, which comprises
both marine and freshwater symbiotic ciliates.
P1.23 PATTI, A*; HOCHBERG, R; LITVAITIS, MK; Univ. Massachusetts
Lowell, Univ. New Hampshire; [email protected]
Taxonomy and Evolution of the Chaetogaster limnaei complex
(Annelida: Oligochaeta)
Chaetogaster limnaei is a well-known symbiotic oligochaete that infects
freshwater molluscs worldwide. In Massachusetts, the ectosymbiotic
subspecies, C.l. limnaei lives in the mantle cavity of freshwater pulmonates
where it feeds on single-celled algae, protists and small invertebrates. In
some snails, however, the oligochaete lives in the host's kidney tissue and
sustains a parasitic relationship, occasionally ingesting trematode cercariae
that also parasitize the host snail. This parasitic form, known as C.l. vaghini,
is considered a subspecies of the ectosymbiont despite differing in some
morphological and reproductive characteristics. In this investigation, we use
molecular sequence data (COI) to determine if these two subspecies are
dissimilar at the molecular level. Results indicate that a distinct barcoding
gap is present between the two subspecies, and that there is an order of
magnitude difference between intra- and interspecific variation. Details on
the morphology of both subspecies are presented, as are hypotheses on the
potential pathways to parasitism in Chaetogaster.
P1.47 PEIFFER, E.K.*; FORD, S.; WILLIAMS, S.H.; Ohio University;
[email protected]
Gape and bite force in the northern grasshopper mouse (Onychomys
leucogaster) and the deer mouse (Peromyscus maniculatus)
Previous studies on the masticatory apparatus of the northern grasshopper
mouse (O. leucogaster) and the deer mouse (P. maniculatus) suggest that
there are architectural differences in the jaw muscles relating to feeding
behavior and diet. For example, for some of the jaw-closing muscles, O.
leucogaster may have a smaller physiological cross-sectional area (PCSA)
but a more favorable lever advantage for producing bite force at the incisors
than P. maniculatus. This configuration is thought to help maintain or
increase bite force capabilities at large gapes in O. leucogaster, which may
be required to facilitate their carnivorous diet consisting of similar-sized
vertebrates. To determine the relationship between gape and bite force in
both species, we collected bite forces at different gapes from 8 individuals of
P. maniculatus and 11 individuals of O. leucogaster using an adjustable bite
force transducer instrumented with strain gauges. Despite the fact that O.
leucogaster weighs almost twice as much as P. maniculatus, both species
prefer to bite at a similar range of gapes, from 4.0 mm to 8.0 mm,
significantly lower than their maximum gapes. Moreover, absolute and
relative maximum bite forces in both species peak at 5.0 mm of gape.
However, as expected O. leucogaster has absolutely and relatively higher
maximum bite forces at each gape. Any structural differences in the jaw
musculature appear to have a negligible influence on producing significantly
larger gapes, but may facilitate the larger bite forces in O. leucogaster.
P1.24 PELEP, Peltin O.*; HADFIELD, Michael G.; University of Hawaii at
Manoa; [email protected]
Distinguishing the validity of subspecies of the endangered Hawaiian
tree snail Achatinella mustelina using a principal component analysis
of shell characters
The endangered Hawaiian tree snail species Achatinella mustelina was
divided into 25 subspecies based on traditional shell characters (Welch
1938). A recent molecular genetic analysis of 21 populations through the
species range yielded no support for the subspecies distinctions. In the
present study 11 shell characters were measured on photos of 50 shells of
each of 19 nominal subspecies using image-analysis software; the shells are
in the collections of the B. P. Bishop Museum, Honolulu. The characters
included both traditional linear measurements (5), plus perimeter (3) and
surface-area (3) measurements. The resultant data were subjected to
principal component analyses to determine the most important discriminating
characters and to answer the question, do the shell characters support
assignment to the nominal subspecies? The principal components (PCs)
explained 95.5% of the variance among measurements, and two, PC1 and
PC2, provided most of the information. Pair-wise comparisons of the
subspecies, based on PC1 and PC2, plus examination of the subspecies
ranges on a map, provided support for 11 of the subspecies (i.e., they were
distinct from all subspecies with overlapping ranges), but not for the
remaining 8 (i.e., they were not distinguished from sympatric subspecies). It
remains for these results to be resolved with the results of molecular genetic
analyses of snails from the same populations.
e288
P3.100 PELUC, S. I.; REED, W. L.*; North Dakota State University;
[email protected]
Differential allocation of carotenoids and testosterone into egg yolks
affects the immune performance of Japanese quail chicks
In birds, females can influence variation in offspring performance by
differentially transferring resources such as nutrients and hormones to eggs.
In this study we assigned 48 female Japanese quail (Coturnix coturnix
japonica) to one of the following treatments: a carotenoid supplemented diet,
an injection of GnRH, a carotenoid supplemented diet combined with GnRH
challenges, and control, over a period of seven weeks. On a weekly basis we
measured carotenoid and testosterone levels in yolks for each female, and
incubated and hatched eggs from these females. After two weeks of growth,
we examined the ability of the chicks plasma to fight off bacteria, and we
measured the dimensions of the bursa of Fabricius on all chicks.
Testosterone levels were higher in eggs from the GnRH challenged females
relative to eggs from carotenoid supplemented or control females, and
testosterone levels were even higher in eggs from females receiving
carotenoid supplemented diets and GnRH challenges. Chicks from females
receiving carotenoid supplemented diets only had considerably enhanced
immune responses. Those chicks had larger bursa than chicks from other
treatments and female chicks had significantly larger bursa than males.
Moreover, bacteria killing ability of their plasma was higher than in chicks
from other treatments. We provide evidence that female allocation of
carotenoids in eggs can influence immune performance of chicks, and
discuss the extent to which increased levels of testosterone in the yolk may
compromise chick immune function.
P3.25 PENALVA-ARANA, D. Carolina*; ROBERTSON, Hugh; LYNCH,
Michael; Indiana University, Bloomington, University of Illinois,
Urbana-Champaign; [email protected]
Can you smell that? Using genomics to demystify Daphnia's
(Crustacea) chemical senses
For years the debate of if, how and which chemical signals can be detected
by Daphnia has plagued freshwater biologists. Daphnia pulex, a sentinel and
keystone species of freshwater systems, thought to be the sister group to the
terrestrial insects, is the first aquatic invertebrate to have its genome
sequenced. Using representative Grs and Ors from all available insects as
queries, we present the chemoreceptor superfamily of D. pulex, finding six
distinct gustatory-like receptors (Grs) clusters, for a total of 58 genes. These
58 Grs form a major species-specific cluster of 49 genes, a smaller cluster of
5 genes, as well as a highly divergent singleton (Gr58). The final three
genes, Grs55-57, share distinctive amino acid motifs and cluster with the
sugar receptors of insects, and may illuminate the origin of this distinctive
subfamily and the potential for Daphnia to detect sugars. This chemoreceptor
gene repertoire presumably mediates the many taste and smell functions of
this crustacean. Consistent with the prediction of Robertson et al. (2003), we
find no evidence of Olfactory receptors (Ors), in particular, no homolog of the
otherwise highly conserved DmOr83b protein, which has orthologs in all
available insect genomes, was found. While it is always possible that this
entire Or gene lineage was lost at some point in the history of Daphnia pulex,
we think it more likely that the insect Or lineage is indeed a relatively recently
expanded lineage concomitant with the evolution of terrestriality in insects or
their hexapod ancestors. We present ESTs and tiling array support for the
predicted gene models, and expression data comparing expression between
the sexes.
P2.47 PEROTTI, Elizabeth A.*; TRAN, Cawa; HUANG, Ying; CAMERON, R.
Andrew; HADFIELD, Michael G.; University of Hawai'i, Manoa, California
Institute of Technology; [email protected]
Developing cDNA libraries for analysis of receptors involved in the
settlement and metamorphosis of a dominant biofouling tubeworm,
Hydroides elegans
Larval detection of specific molecular cues on the substratum during
settlement and metamorphosis is still a process we know very little about.
The tubeworm Hydroides elegans is a significant problem fouler in warm
water ports around the world and is an excellent candidate for investigating
molecular reception during larval settlement and metamorphosis. By
developing cDNA libraries and using other downstream molecular
techniques, we are able to examine and identify larval receptor systems and
provide a significant contribution toward understanding the interaction
between bacterial ligands and larval receptors during recruitment and
metamorphosis of marine biofoulers. Our primary goal is to develop
stage-specific gene libraries for pre-competent and metamorphically
competent larvae of H. elegans that can be arrayed and examined for
specific receptor genes in several ways. Specifically, we have synthesized a
3-5 RACE library from H. elegans larvae and will create a cloned, arrayed,
and printed library. Likely candidates for receptors during settlement that can
be screened using these libraries include lectin receptors, ligand-gated ion
channels, and G-protein-coupled receptors (GPCRs). Preliminary results
indicates that cDNA from competent larvae have abundant GPCRs. This
study is an important step in identifying both the nature and the location of
receptors for bacterial ligands that stimulate larval settlement and for
determining the chemical cues and molecular specificity of the stimulating
ligands.
P3.11 PERRAULT, J.*; WYNEKEN, J.; JOHNSON, C.; THOMPSON, L.J.;
MILLER, D.L.; Florida Atlantic University, FAU, Loggerhead Marinelife
Center, Nestle Purina PetCare, VDIL, University of Georgia;
[email protected]
Why is nest success low? Hg, Se, and blood parameters in nesting
leatherback sea turtles (Dermochelys coriacea) and their young.
Leatherback sea turtles have low hatch success compared to other sea turtle
species. We investigated potential causes of low hatch success and
hatchling vigor. We hypothesized these and other anomalies found in
dead-in-nest leatherbacks are correlated with Hg and Se levels (Se
detoxifies Hg). We surveyed dead hatchlings for evidence of Hg exposure
and other indicators of compromised vigor. Blood collected from 40 nesting
leatherbacks was analyzed for Hg, Se, and blood parameters. Their nests
were inventoried after emergence and we examined those results for
relationship to maternal health. Maternal blood Hg and Se concentrations
ranged from 1-77 ppb and 0.4-20 ppm, respectively. Neither significantly
correlated with hatchling emergence success. Hg levels decreased over time
in turtles that were sampled in sequential nesting events, suggesting
maternal transfer to the offspring. Maternal Se tended to increase as the
season progressed, indicating that these turtles may be feeding on Se-rich
food sources between nesting events. Next, blood samples from live
hatchlings, and livers collected from dead-in-nest hatchlings were analyzed.
For hatchlings, liver Hg ranged from 0.1-0.3 ppb and liver Se ranged from
1-2 ppm. Hatchling blood Se ranged from 1-7 ppm. Two metabolic measures
from blood surveys correlated with emergence success (anion gap, BUN);
their functional relationship is unclear. We also analyzed liver Hg and Se in 6
hatchlings (<5 days old) brought into the lab for a separate study. Hg
concentrations in these turtles increased with age, consistent with Hg
mobilization from the yolk sac. Our study is the first to establish Hg and Se
levels in hatchling leatherbacks, and to identify the roles of their mothers in
transferring their Hg and Se loads to their offspring.
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P3.139 PETCHLER, E.M.*; IYENGAR, E.V.; Muhlenberg College, Allentown
PA; [email protected]
Eat and run: Predator preference for and escape responses by potential
hosts of the snail Crepidula adunca (Mollusca, Gastropoda)
When a species strictly associates with only one host, despite the presence
of many similar alternatives, the question arises as to what selection
pressures are driving the specificity of this symbiosis. The
suspension-feeding, epibiotic, marine snail Crepidula adunca is found almost
exclusively on the host snail Calliostoma ligatum in the San Juan Islands,
Washington. This fidelity is especially surprising considering that other
potential hosts, including the similarly-shaped, confamilial snail Margarites
pupillus, exist in the same habitat. We investigated whether predator
preference for hosts other than C. ligatum may have contributed to the
evolution of C. adunca's specialization on C. ligatum. The sea stars Pisaster
ochraceus and Leptasterias hexactis, the crabs Cancer productus and
Cancer oregonensis, and the snail Lirabuccinum dira are the dominant
predators that co-occur with Crepidula adunca. Of these, Leptasterias
hexactis is the most voracious predator of both C. ligatum and M. pupillus,
and contact with L. hexactis causes a violent reaction in individuals of these
species of snails. Leptasterias hexactis prefers to consume Margarites
pupillus, the snail not utilized by Crepidula adunca, rather than the host
Calliostoma ligatum. This preference is not just due to differences in escape
behaviors between the snails, because the sea star consumes more
individuals of M. pupillus than C. ligatum when the snails are prevented from
moving. Other anti-predatory behaviors, such as running speed and
defensive tactics may also contribute to higher rates of predation for M.
pupillus compared with C. ligatum. Thus, host choice by Crepidula adunca is
likely due, at least in part, to relative risks of predation for the various host
species.
P3.212 PETERSEN, A.M; ELLERBY, D.J.; FEILICH, K.*; Wellesley College;
[email protected]
Thermoregulatory and metabolic response to feeding in the medicinal
leech Hirudo verbana
Leeches are subject to selective pressure for rapid recovery of locomotor
capacity following large blood meals in order to avoid predation or host
detection. Feeding can result in mass increases of more than 400% following
feeding in some individuals, and presents a unique challenge to these
animals in terms of maintaining mobility post-feeding. We have found that
leeches are able to recover up to 50% of pre-feeding locomotor capacity
within 1hr of a meal, even though total digestion may take months. It is not
currently clear what, if any, metabolic compensation occurs in order to meet
the increased digestive and locomotory energy demands in the hours
following feeding. We performed a series of experiments on the medicinal
leech, (Hirudo verbana), following a blood meal, in order to test whether
energy requirements for digestion and rapid return to locomotor capability
are met via 1) increased oxygen consumption, 2) mobilization of intracellular
carbon stores, or 3) behavioral thermoregulation. Following feeding, the
preferred body of temperature of fed leeches was found to be higher than in
unfed leeches. Additionally, post-prandial changes in aerobic and anaerobic
metabolism occur that may contribute to recovery from feeding. These data
offer insight into possible adaptive mechanisms contributing to the rapid
locomotor recovery of leeches following a blood meal.
P3.213 PHILIP, B.N.; LEE, R.E.*; Miami Univ., Oxford. Ohio;
[email protected]
Aquaporin-3 expression correlates with seasonal acquisition of freeze
tolerance in the goldenrod gall fly, Eurosta solidaginis
Some invertebrates have evolved adaptations to survive freezing of their
bodily fluids during subzero temperature exposure. The accumulation of
cryoprotectants, such as glycerol, and the redistribution of water between
body compartments play central roles in their capacity to survive freezing.
The movement of glycerol and water into and out of the cell is facilitated by
aquaporins, which are pore-forming transmembrane proteins. Recent studies
demonstrated that there is a significant decrease in freeze tolerance when
molecular movements through aquaporins are blocked. Larvae of the
goldenrod gall fly, Eurosta solidaginis, are freeze-intolerant during the
summer, but develop their capacity for freeze tolerance through the autumn.
To determine whether aquaporin expression is correlated with their
acquisition of freeze tolerance, E. solidaginis larvae were collected monthly,
from July through January. As expected, larvae developed progressively
greater levels of freeze tolerance through the autumn. Also, glycerol
concentration increased in the larvae as the plant gall tissues around them
senesced and dried. Following each field collection, membrane- and
soluble-protein fractions were isolated from larval homogenates.
Immunoblots using rat anti-AQP3, a water- and glycerol-permeable
aquaporin, showed a gradual increase in membrane-bound AQP3 from July
through January. In contrast, AQP3 proteins in the soluble fraction peaked in
September and gradually decreased through December. These results
support the hypothesis that AQP3 expression increases concomitantly with
increasing freeze tolerance in E. solidaginis. Supported in part by NSF grant
#IOB-0416720.
P3.163 PHILLIPS, M. M.*; LYNN, S. E. ; The College of Wooster;
[email protected]
Repeated Handling Does Not Affect Hypothalamo-Pituitary-Adrenal
Development In Eastern Bluebird Nestlings (Sialia sialis)
In vertebrates, the hypothalamo-pituitary-adrenal axis is activated by a
variety of unexpected events. In both wild and captive vertebrates, prior
experience with a stressor has been shown to alter adults responses to
subsequent stressors; however little is known about the effects of prior
experience on developing animals. We studied nestling eastern bluebirds
(Sialia sialis) with two goals in mind: (1) to document the time course over
which HPA responsiveness to handling develops in this species; (2) to
assess the effects of repeated handling on HPA responsiveness. To address
goal 1, we subjected previously unhandled chicks to a capture/handling
protocol when they were 6, 9, or 15 days old, and measured plasma
corticosterone at 0, 15, and 30 min post-capture. To address goal 2, we
handled chicks every three days, beginning with hatch, and subjected
handled chicks to the capture/handling protocol when they were 6, 9, and 15
days old. Day 15 chicks showed a greater adrenocortical response than day
6 or day 9 chicks. Day 15 chicks exhibited an adult-like like response in
magnitude of corticosterone secretion; however, the duration of the response
was attenuated. No repeated-handling effects were found in any age group.
Our results indicate that eastern bluebirds exhibit HPA responsiveness on a
timeline that is similar to patterns previously demonstrated in other altricial
species. However, even though prior experience with the capture-restraint
paradigm is known to alter the response of adults, we did not demonstrate
such an effect in nestlings. This suggests that the ability to habituate to
stressors may differ by developmental stage.
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P2.59 POCKLINGTON, EM*; ZALISKO, EJ; MAXSON, KA; BROWN, L;
Blackburn College; [email protected]
A New, Non-Lethal Phenotype, the Blackburn College Floater
(BC-Floater), in the Axolotl (Ambystoma mexicanum)
Three generations of captive-bred axolotls (Ambystoma mexicanum) reveal a
new, non-lethal phenotype that results in the sustained inflation of the lungs
for weeks to months. Affected animals inhale but rarely exhale. Animals
expressing this phenotype float inverted or listing for two or more
consecutive weeks, with trunks breaking the water surface. The new
phenotype, designated the Blackburn College Floater (BC-Floater), was first
documented in crosses raised in Blackburn College laboratories. Over three
years, crosses were raised under similar laboratory conditions (20-25 C with
local photoperiods). A repeated cross produced 29% and 25% BC-Floaters
in successive years. That same male crossed with a different female
produced only 2% offspring that matched the floater phenotype. Subsequent
crosses of BC-Floaters that had recovered to normal body posture exhibited
an unclear pattern of incomplete penetrance. Two crosses of F1 BC-Floaters
produced 20% and 21% BC-Floater offspring. Two crosses of F2 BC-Floaters
produced 8% and 10% BC-Floater offspring. Axolotls first exhibited the
floating phenotype at 21-80mm total length and 3-15 weeks post-hatching
(mean=43mm and 8 weeks, N=55 representing animals from 3 crosses). By
one year of age, most BC-Floaters either recovered to a normal body posture
and ventilation of their lungs or died from the apparent stress of the
continued inverted condition. In still, shallow water (5cm), recovery was slow
and irregular; 8 of 29 (28%) BC-Floaters recovered by nine months. In 25cm
deep water (with turbulence generated by a hanging power filter) 42 of 44
(93%) six month-old BC-Floaters reverted to a normal body posture within 10
days.
P3.137 POLNASZEK, Timothy*; ARTITA, Kimberly S.; SEARS, Michael W.;
Southern Illinois University; [email protected]
Should I stay or should I go? Optimal decisions for attack and flight
during predator-prey interactions
One of the most important decisions that a prey makes during its lifetime is if
and when to flee from a predator. To date, all theoretical treatments of flight
initiation predict that a prey should flee when it detects a predator in the
environment. However, prey might gain considerably by not fleeing if they
are successfully cryptic or if predators fail to attack. Previous models of flight
initiation make very simple assumptions regarding the detectability and
perceptual abilities of predators and prey; e.g., prey are always detected
when they are within a specified perceptual distance from the predator. Here,
we relax these assumptions for both predator and prey by allowing the
probabilities of detection to decay with distance and direction according to a
set of probability density functions. These probability density functions define
the perceptual ranges of the predator and prey. By modifying shape
parameters of these probability distributions, we simulated several types of
searching strategies for predators and vigilance strategies for prey.
Assuming that individuals want to maximize net energy intake per time, we
simultaneously solved for the optimal probabilities of prey flight and predator
attack during these simulations using evolutionary algorithms. Contrary to
earlier models, we found that prey do not necessarily flee once they have
detected a predator, nor do predators immediately attack once a prey is
detected. This result is likely a direct consequence of imperfect perception
and detectability of the predator and prey. Future directions for this work
include directly linking predator and prey strategies to fitness (as a function
of age), and searching for multiple strategies indicative of predator-prey
games under different abundances and distributions of prey.
P2.82 PORTIS, L.M.*; MINER, B.G.; Colby College, Waterville, ME, Western
Washington University, Bellingham, WA; [email protected]
The effect of sea star predators on the retractability of the whelk
Nucella lamellosa
Several studies have indicated that the whelk Nucella lamellosa displays
phenotypic plasticity in response to predation threat from the predatory crab
Cancer productus. Less research has been performed on the phenotypic
plasticity of N. lamellosa in response to another major predator, Pisaster
ochraceus. This study looked to expand upon this body of research. It was
found that the presence of waterborne cues from P. ochraceus induces
changes in the retractability of N. lamellosa. N. lamellosa held in the
presence of sea stars had greater retractability than those held without sea
stars. Further, N. lamellosa exposed to sea star cue were less likely to be
preyed upon by P. ochraceus than those not previously exposed to cue.
Greater retractability in N. lamellosa was correlated with less mortality in the
predation experiment, suggesting that retractability is an inducible defense
against sea stars.
P2.87 POWERS, S.D.*; ANDERSON, R.A.; Western Washington University;
[email protected]
How Does Spatial Variation in Climate Cause Spatiotemporal Patterns
in Lizard Energetics?
A lizards ability to be active and to acquire food for growth, storage, and
reproduction is expected to be seasonally constrained by the complex,
dynamic set of phenomena that comprise climate. Hence variation in climate
among locales should vary in how they constrain lizard activity and
production. The western fence lizard (Sceloporus occidentalis) occupies a
diversity of ecosystems from southern California to central Washington. Two
locales that contrast markedly in climate in Washington state, in the northern
end of the species geographic range, are coastal temperate forest and the
warm, dry pine-oak woodland of the states interior. How S. occidentalis is
affected by this geographic climate change was examined by correlating
daily and seasonal patterns of temperature, precipitation, and cloud cover
with the patterns of lizard daily activity and energy expenditure, feeding rates
and food availability along with related aspects of lizard population structure.
Despite the greater food availability for coastal lizards, the lizards in the
warm, sunny woodland site were active longer, ate more, and grew faster.
Currently, the optimum climates for this species are not known, but future
investigations of elevational and mesic-xeric gradients may enable
predictions of population structure and population density patterns in the face
of climate change.
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P1.72 PRENTICE, N.E.*; WIKELSKI, M.; ROMERO, L.M.; FLORANT, G.L.;
Colorado State University, Princeton University, Tufts University;
[email protected]
Non-Esterified Fatty Acid Concentrations in Galápagos Marine
Iguanas during a Mild El Niño Year
The Galápagos marine iguana (Amblyrhynchus cristatus) undergoes long
periods of fasting during an El Niño year. How these animals are able to
survive periods when food is scarce is unclear. During a fast, we predicted
that these animals mobilize endogenous fat stores to meet metabolic energy
requirements. Plasma concentrations of non-esterified fatty acids (NEFA) are
generally indicative of fat metabolism in fasting animals. We investigated
plasma NEFA concentrations in marine iguanas collected in January of 2007,
which was a mild El Niño year. Blood samples from both female and male
marine iguanas were analyzed in this study. We also determined body mass
(g) and body condition index (( body mass/snout-vent length3) x 106) of the same
animals in order to correlate NEFA concentrations with body condition. We
hypothesized that the animals with a low body condition index would have
low plasma NEFA levels and would be less likely to survive. Our data
suggest that in female iguanas there is a positive correlation between body
mass and snout-vent length (SVL) ( R 2 = 0.34; n = 19) and a positive
correlation for body condition index vs. plasma NEFA concentrations (R2 =
0.33). Male iguanas did show a positive correlation between body mass and
SVL ( R 2 = 0.32; n = 70), but did not show any correlation between body
condition index and NEFA concentrations. Overall, we conclude that female
iguanas in 2007 were in better condition to survive a long fast compared to
male iguanas.
P2.181 PREUSS, K.M.*; NIJHOUT, H.F.; Duke University;
[email protected]
The importance of threshold size for the initiation of metamorphosis in
the insect Tribolium castaneum
Proper timing is critical for the initiation of metamorphosis because cessation
of the larval developmental period determines the final body size of adult
insects. Although many of the processes involved in metamorphosis have
been well characterized, little is known about the timing of the initiation of
metamorphosis. I used the red flour beetle, Tribolium castaneum, to
investigate the initiation of metamorphosis. T. castaneum has a highly plastic
larval developmental period, which can vary in length by over two weeks.
Using different strains and varied nutritional conditions, I was able to
document the existence of a threshold size, which determines when the larva
becomes competent to metamorphose. Threshold size, however, does not
dictate the exact timing of initiation. The exact timing for the initiation of
metamorphosis is determined by a pulse of the molting hormone, ecdysone,
but only after threshold size has been reached. Ecdysone pulses before the
larva attains threshold size only cause the larva to molt to another larval
instar. These results indicate the timing of metamorphosis initiation is
controlled by two factors: (1) attainment of threshold size, at which the larva
becomes competent to initiate metamorphosis and (2) the timing of an
ecdysone pulse after attaining threshold size. Using these factors, I have
developed a predictive model of the larval developmental period for T.
castaneum.
P3.214 PRICE, Edwin R*; ARMSTRONG, Christopher; STAPLES, James F;
GUGLIELMO, Chistopher G; University of Western Ontario; [email protected]
Norepinephrine stimulated fatty acid mobilization in hibernating ground
squirrels (Spermophilus tridecemlineatus)
Hibernating mammals rely almost exclusively on lipid to fuel hibernation and
arousal, so adipose tissue must deliver adequate stored fat to the circulation,
even at temperatures that approach 0 degrees C. We excised white adipose
tissue from thirteen-lined ground squirrels in late summer and in hibernation
and incubated it with epinephrine at either 4 or 37 C. Measurements of
glycerol released to the incubation medium indicate that squirrels had higher
rates of lipolysis during hibernation at both temperatures. The data suggest
that adipose tissue may become more responsive to catecholamines during
hibernation. Further research will focus on selective mobilization/retention of
particular fatty acids during the hibernation phase.
P3.66 PROPERT, Matthew W.G.*; TRUONG, Rosemary; HITCHCOCK,
Amanda C.; MARSH, Richard L.; Northeastern University;
[email protected]
Fibularis longus function varies with joint angle due to tendon
architecture during legged locomotion and jumping in birds.
The fibularis longus (FL) is quite unusual in its architecture. As one of the
largest of the muscles in the shank of birds, the FL is able to produce a
relatively significant force; and its branched distal tendon inserts at three
different joints: the ankle, the tarsometatarsal-phalangeal (TMP), and the
interphalangeal (IP) joints. Previously some have assumed that the FL
functioned at the ankle perhaps because this is the largest branch of the
tendon. However, we have shown that the tendon insertions are such that
the FL function switches depending on the combination of joint angles. The
long tendon that inserts at the TMP passes near the center of rotation of the
ankle and this anatomy suggests that the effective moment arm will change
depending on the combination of joint angles. We used the tendon excursion
method to measure the instantaneous moment arm at the joints when
moving one joint and immobilizing the other at various angles. We also
measured joint angles in guinea fowl during stationary jumping and legged
locomotion as well as determining FL function during these activities using
sonomicrometry and electromyography. Our data shows that at the angles
used in legged locomotion the FL acts mostly as a toe flexor, but when
jumping the FL switches from an ankle extensor early to a toe flexor just
before takeoff. We also found that the FL utilizes elastic energy storage to
power the jump. Supported by NIH AR47337 and NSF IOB-0542795.
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P3.215 PRUITT, N. L.*; ARNOLD, A.; ESPINAL, N. A.; JOO, Y. J.; Colgate
University, Hamilton, NY; [email protected]
Dehydrin-Like Proteins in Freeze-Tolerant Larvae of the Goldenrod Gall
Fly Eurosta solidaginis
Third instar larvae of the goldenrod gall fly Eurosta solidaginis (Diptera:
Tephritidae) from populations in North America change from
freeze-susceptible to freeze-tolerant just prior to the onset of winter. While
studies have documented the accumulation of carbohydrate cryoprotectants
during this transition, protein cryoprotectants common in other freeze-tolerant
species are less well established in this insect. Using larvae collected from a
population in Madison County, NY, which changes from freeze-susceptible to
freeze-tolerant in early October, we found evidence of a protein
cryoprotectant in freeze-tolerant larvae and larvae that were in the process of
transitioning to freeze tolerance. The putative cryoprotective protein has
characteristics similar to dehydrin proteins, previously described only in
flowering plants. For example, when the freeze-labile enzyme rabbit lactate
dehydrogenase is frozen in the presence of protein from freeze-tolerant or
transitional gall fly larvae, up to 80 percent of the enzyme's activity is
preserved. Similar to plant dehydrins, the active gall fly fraction is heat stable
and does not bind to a weak anion exchanger. Immunoblots using an
antidehydrin antibody specific to the lysine-rich K segment of angiosperm
dehydrin showed a positive response to gall fly proteins from transitional and
freeze-tolerant larvae, but not to proteins from freeze-susceptible larvae.
Based on these Western blots, the estimated molecular weight of the gall fly
dehydrin-like protein is 66 kDa.
P2.50 PULEO, A*; O'BRIEN, S; HOCHBERG, R; Univ. Massachusetts
Lowell; [email protected]
Metamorphic transformation of the corona in the predatory rotifer,
Acyclus inquietus (Monogononta): the fate of the muscular system
The atrochid rotifer, Acyclus inquietus, is an unusual predator in the sense
that it maintains a sedentary lifestyle while embedded within its prey, the
colonial rotifer Sinantherina socialis. As the atrochid infiltrates and becomes
permanently associated with the colony, individuals of A. inquietus undergo
an extraordinary metamorphosis that allows them to feed surreptitiously on
neonates and adults of S. socialis. Feeding is accomplished by use of the
infundibulum, a non-ciliated, muscular, hood-like structure that covers the
mouth. The infundibulum is derived from the ciliated corona, a typical
rotiferan feature and one that is present in neonates of A. inquietus. In this
study, we examine the structure and muscular supply of both the neonate
corona and the adult infundibulum to understand the events that take place
during metamorphosis. We use digital microvideography to capture the
behavior of both lifestages, brightfield microscopy to follow metamorphosis,
and fluorescent phalloidin and CLSM to study the fate of the muscular
system. We also compare the somatic muscle patterns of both lifestages to
those of other species of Monogononta to make statements about the
homology of specific muscle sets within the Rotifera.
P3.62 QUITT, M.A.*; KANG, J.K.; DAVIDSON, B.C.; NGUYEN, C.T.;
ADOLPH, S.C.; AHN, A.N.; Harvey Mudd College, Claremont;
[email protected]
Variability of Walking in Humans
Almost all humans walk, but the morphology of their leg muscles and
kinematics of their gait patterns differ visibly among individuals. In this study,
we examine the relationship between the variability of gait patterns and
neural control patterns with differences in body shape (i.e., muscle size)
during walking in 19 young adults (mass = 60.9 +/- 6.9 kg; height = 1.67 +/0.09 m; average SD). We used ultrasonography to measure muscle
morphology of the lateral gastrocnemius (LG), medial gastrocnemius (MG),
and soleus (SOL) muscles at rest, and then recorded the muscle activity
patterns (% maximum voluntary contraction, MVC) of these muscles and
joint kinematics (Qualysis) during walking on a treadmill at 0.6 m/s. In 37% of
the individuals (Group A), LG muscle activity levels were one-third to
one-sixth that of the MG muscles, whereas the other subjects (Group B)
showed roughly equal activity of the MG and LG muscles. Group A had
shorter SOL muscles (t-test, p = 0.03), and tended to have smaller calf
muscles in several other respects: LG thickness (p = 0.16), LG muscle length
(p = 0.11), and LG muscle width (p = 0.18). Group A individuals were also
slightly shorter in height (p = 0.04) with shorter lower legs (p = 0.11). There
seemed to be no difference in pattern and amplitude of hip, knee, and ankle
angles between the two groups. Individuals with slightly different
morphometrics seemingly use different muscles to produce similar kinematic
and mechanical output. The neuro-muscular input can vary, even though the
mechanical output to produce walking is similar. This study was supported by
a Barbara Stokes Dewey Endowment and HHMI.
P2.11 RACK, J.M.*; HO, W.W.; SMITH, G.T.; Slippery Rock Univ., PA,
Indiana Univ., Bloomington; [email protected]
Sexual dimorphism of electrocommunication signals across
populations of the weakly electric fish Apteronotus albifrons
Weakly electric fish produce electric organ discharges (EODs) for
electrolocation and communication. Both EOD frequency (EODf) and EOD
modulations (chirps) vary across species, sexes, and individuals. EOD
modulations can also vary across populations of the same species (Turner et
al. 2007). The focus of this study was to examine population-level variation in
the sexual dimorphism of electrocommunication signals. We characterized
EODs in four populations of A. albifrons, and used mtDNA cytochrome-b
sequence to examine genetic relationships between populations. Individuals
from populations in the Orinoco drainage (CO-oc and CO-jn) or the Amazon
drainage (PE and BR) were presented with playbacks of synthetic
conspecific EODs, and their EODs and chirps recorded. EODf was sexually
dimorphic in both CO populations, but did not differ significantly between the
sexes in the PE and BR populations. Consistent with previous studies
(Dunlap et al. 1998; Kolodziejski et al. 2005), chirp rate did not differ between
sexes in any of the A. albifrons populations. Chirp frequency modulation and
duration were also sexually dimorphic in the Orinoco, but not the Amazon
populations. Overall, populations from the same river systems were more
genetically and behaviorally similar than populations in separate river
systems. This is consistent with the hypothesis that diversity in sexually
dimorphic EOD behavior has evolved in allopatry, with South American
watersheds acting as barriers for reproductive isolation.
e293
P2.99 RADE, C. M.*; CIUMMO, E. M.; WARD, A. B.; Adelphi University;
[email protected]
The evolution of fin reduction and loss in fishes
Body elongation has evolved a number of times independently in
vertebrates. In highly elongate vertebrates, the limbs/fins are often reduced
or lost. For example, a number of elongate tetrapods have been described
as having reduced limbs; many times in association with a transition to a
burrowing habit. Less is known about changes to the fins in elongate fish
lineages. Previous study has shown that loss of the pelvic fins has occurred
in a number of fish lineages regardless of body shape. The goal of this study
was to determine whether there is fin reduction in fish lineages where there
is body elongation and to determine the specific musculoskeletal changes
associated with fin reduction in fishes. In this study, we collected fin and
body measurements from a number of ostariophysan and gasterosteiform
species. Additionally, we have described the musculoskeletal anatomy for at
least two species that differ in degree of body elongation from both
Ostariophysi and Gasterosteiformes. Highly elongate members of these
lineages do not have pelvic fins. Our results indicate that the pectoral fins are
smaller in more elongate fishes in these lineages. In examining the
musculoskeletal system of elongate and non-elongate species from the
same lineage, we have found that there is a difference in number and
arrangement of the pectoral fin muscles between closely related elongate
and non-elongate species. This work provides a critical basis in
understanding anatomical changes to the paired fins that are associated with
changes in body shape.
P3.39 RAKOW SUTHERLAND, K*; MADIN, L; MIT/WHOI Joint Program in
Oceanography, Woods Hole Oceanographic Institution; [email protected]
In situ filtration rates of pelagic tunicates: results from morphometric
measurements
Salps are suspension-feeding pelagic tunicates that filter higher volumes of
seawater than almost any other planktonic grazer. Oral and atrial siphons are
at opposite ends of the barrel shaped body and a unidirectional feeding
current is produced by rhythmically contracting circular muscle bands.
Seawater and associated small particles (0.1 m-1mm) are filtered through a
mucous mesh that fills the mostly hollow pharyngeal cavity. Accurately
measuring filtration rates poses a challenge because salps are delicate,
difficult to collect and maintain, and may not behave normally in the
laboratory. Morphometric analysis of salps swimming in situ provided a way
to measure the volume of fluid passing through the mucous filtering mesh.
High definition video sequences were collected by SCUBA divers and then
video frames were digitized to measure time-varying swimming kinematics
and body volume over a pulse cycle. This in situ technique has been applied
to several species of salps and compares reasonably to results from other
methods. Differences in filtering efficiency between Salpa cylindrica, Pegea
confoederata and Cyclosalpa sp. will be presented.
P1.97 RAMBERG PIHL, Nicole/C*; WATSON, Winsor/H; CHABOT,
Christopher/C; Plymouth State University, University of New Hampshire;
[email protected]
Do Circatidal or Circalunidian Clocks Control Locomotor Rhythms in
the American Horseshoe Crab?
Like many other inter-tidal dwellers or visitors, the American Horseshoe
Crab, Limulus polyphemus, expresses endogenous locomotor activity
rhythms that can be synchronized to the tides. While these biological
rhythms have been long recognized, the nature of the timing system
controlling them is somewhat controversial: the system could theoretically be
comprised of either two 24.8h (circalunidian), or one 12.4h (circatidal) clock
and there is evidence that seemingly supports both possibilities. The
horseshoe crab expresses exceptionally clear circatidal rhythms and is thus
a good choice for addressing this issue. Our results suggest the presence of
two circalunidian clocks in horseshoe crabs: 1) When animals were given
two tidal cues of different periods (24.8 and 24.2h), synchronization to both
tides occurred. 2) In some animals these rhythms persisted in constant
conditions in phase with previous tidal cues suggesting entrainment of two
separate clocks. 3) Rarely, but significantly, two bouts of activity were
expressed, each with different free running periods. 4) In other experiments,
only one bout of activity/day was evident during either constant conditions or
during tidal cycles; later under the same conditions, two bouts of activity/day
could be observed. Taken together these results and others are consistent
with the hypothesis that in this species locomotor activity is controlled by two
circalunidian oscillators that are strongly coupled. In addition, since it is not
uncommon to see only one bout of activity/day, decoupling of one of the
oscillators from downstream locomotor centers may commonly occur, an
outcome that could serve intertidal species well in areas where there is only
one tide/day.
P1.153 RATHBURN, C.K.*; BURNETT, L.; GROSS, P.; BEAL, M.; VELOSO,
A.; COOK, M.; BURNETT, K.; College of Charleston, SC , C of C, SC,
Medical University of South Carolina, Charleston, Hollings Marine
Laboratory, Charleston, SC, HML, Charleston, SC, MUSC, Charleston;
[email protected]
Transcriptional Profile of the Penaeid Shrimp Litopenaeus vannamei to
Hypoxia and Hypercapnic Hypoxia
Many crustaceans inhabit estuarine ecosystems where they are frequently
exposed to hypoxia. High levels of CO 2 (hypercapnia) often occur in the
presence of hypoxia, and both factors may impair the abilities of crustaceans
to maintain optimal metabolic processes, preserve acid-base balance, and
uphold immune defense against pathogens. Many of the strategies employed
by marine crustaceans to cope with hypoxia and hypercapnia involve
changes in transcription and translation of sets of genes, some of which may
be uniquely linked to these stressors and some of which may be components
of a common stress response in shrimp. In the present study we tested the
hypothesis that stress responses of Litopenaeus vannamei to hypoxia (PO2 =
4.0 kPa, PCO2 < 0.06 kPa) and hypercapnic hypoxia (PO2 = 4.0 kPa, PCO2 =
1.8 kPa) are represented by unique transcriptional profiles as compared to
normoxia (PO2 = 20 kPa, PCO2 < 0.06 kPa) or to each other. Shrimp were
held for either 4 h or 24 h (n=9 per treatment and timepoint). At the end of
the treatment period, gill and hepatopancreas were dissected and preserved.
RNA isolated from hepatopancreas of individual animals was hybridized to
custom oligonucleotide microarrays containing 22,000 unigenes expressed in
L. vannamei. These results should contribute to a more detailed
understanding of shared and unique gene sets involved in the crustacean
stress response to environmental change. Supported by NSF IBN-0212921
and NOAA OHH at HML.
e294
P2.7 REBAR, D*; ZUK, M; Univ. of California, Riverside; [email protected]
The importance of courtship song in female mate choice in the Pacific
field cricket, Teleogryllus oceanicus
In many animals, multiple signals, in one or more modalities (e.g. visual and
chemical) and either simultaneously or separately, are used in mate
selection. More specifically, field crickets have two acoustic signals used in
mate choice: a calling song which attracts females from a distance and a
courtship song that follows once a female makes contact with a male. Much
research has focused on the role of the calling song, but significantly less
has looked into the role of the courtship song and mate selection. The
courtship song of the Pacific field cricket, Teleogryllus oceanicus, is
important in eliciting a proper female mounting response, but whether
females prefer certain males over others based on the song itself is
unknown. By employing a two day mating tournament, we predicted that the
preferred males would have courtship songs that were longer in length with a
higher duty cycle (more sound per unit time) and a lower fundamental
frequency. The tournament demonstrated that females do in fact base their
mating decisions on the courtship song itself, and preferred males have
longer courtship songs with a higher duty cycle, but not necessarily a lower
frequency. These results are consistent with the idea that the courtship song
is potentially conveying information about the quality of the male.
P2.66 REBECCA, Vito W*; PORTER, Marianne; LONG, John H, Jr; ROOT,
Robert G; Lafayette College, Vassar College; [email protected]
Comparative harmonic analysis of the swimming of an electric ray
(Narcine brasiliensis) and a biomimetic robot
Swimming mechanics are often quantified using digital particle velocimetry
and studying kinematics using high-speed video. These methods have
limitations with flow rates and video capture techniques. Simple image
processing and statistical methods offer means to examine aspects of
body/caudal fin swimming kinematics from video footage as another
technique for quantifying swimming kinematics. We recorded ventral images
of body caudal fin swimming in an axially undulating electric ray Narcine
brasiliensis and a biologically inspired axially undulating autonomous robot of
similar body and tail shape. We analyzed the video footage to compare
propulsive physiology. Analysis involves processing the video to identify
2-dimensional motion of the tail. This motion is expressed in the inertial
coordinates of the swimmer, lateral and axial, and a periodic mathematical
framework is imposed on the processed data via regression. We compare
the phase and amplitude of motion at corresponding positions, and find that
the fish and robot swim differently despite their morphological similarity. We
can offer unique insights into the passive and active mechanics of body
caudal fin swimmers using these computational techniques.
P2.127 REED, BR; BENNETT, VA*; Clarion University, Pennsylvania;
[email protected]
Diapause regulation in Pyrrharctia isabella
When trying to survive stressful environmental conditions, insects can enter
one of two types of dormancy: quiescence or diapause. Quiescence is a
direct response to current conditions and is easily reversible when conditions
revert to normal. In contrast, diapause occurs in anticipation of unfavorable
seasonal conditions and is characterized by a period of insensitivity to
current conditions. Metabolic depression is an indicator of diapause.
Pyrrharctia isabella overwinters as the banded woolly bear caterpillar.
Previous studies found that P. isabella in northern populations enter
diapause. However it was suggested that there may be latitudinal population
differences in the type of dormancy P. isabella enters. We examined a
Pennsylvania population of P. isabella larvae. We exposed fall and winter
field acclimatized larvae to summer temperatures and photoperiod, and
measured changes in metabolic rates and development. Although metabolic
data were inconclusive, winter collected larvae continued development while
fall collected larvae did not, thus indicating that this population enters
diapause and not quiescence. Our current objective is to repeat metabolic
measurements and determine how long this Pennsylvania population of P.
isabella larvae remain in refractory phase of diapause and when diapuse is
terminated. We will expose field acclimatized larvae from early October
through late December to summer temperature and photoperiod periodically
throughout the fall and winter. We will record changes in metabolic rates and
continuation of development. We will also measure seasonal changes in
supercooling points and glycerol production as indicators of freeze-tolerance.
Data are forthcoming.
P2.88 REED, Wendy L.; North Dakota State University;
[email protected]
Mechanisms of maternal yolk corticosterone action in developing
Japanese quail
Evidence from a wide variety of species indicates that exposure to maternal
steroids during development can have long-lasting effects on offspring
phenotypes. Maternally derived corticosterone in avian eggs influences the
development and function of the hypothalamic-pituitary-adrenal (HPA) axis
later in life, however, the developmental mechanisms by which maternal
steroids act are elusive. I injected Japanese quail (Coturnix coturnix
japonica) eggs either with corticosterone (9 ng) or an oil vehicle prior to
incubation and evaluated mRNA expression of the SF-1 receptor in 3.5 d old
embryos using quantitative RT-PCR. Steroidogenic factor 1 (SF-1) is an
orphan nuclear receptor that plays a critical role in gonad development and
differentiation as well as normal adrenal development and function. Elevated
corticosterone in eggs significantly decreases SF-1 expression relative to
vehicle-treated controls prior to gonad or adrenal gland development in the
embryo. These results indicate that maternal steroids may have
organizational effects on developmental processes that occur very early in
development, prior to the embryos own production of steroids.
e295
P3.29 REESE, S. A.; BLACK, P.*; ADAIR, E.; KOETHER, M.; Kennesaw
State University; [email protected]
Hatchling shell content and grownth in an anoxia-intolerant species of
turtle, Red-eared slider turtles (Trachemys scripta)
Adult aquatic turtles usually spend the winter months submerged underwater
to escape freezing temperatures. In northern lattitudes, this can lead to long
months without access to air as the surface waters freeze. If O2 is available
in the water, aquatic turtles utilize various extrapulmonary routes to extract
oxygen from the water. However, in some hibernacula, there is little
(hypoxia) to no (anoxia) O2 available in the water. Some species of turtles
(anoxia-tolerant), namely painted turtles (Chrysemys picta) and common
snapping turtles (Chelydra serpentina) can survive these prolonged bouts of
anoxic submergence by buffering metabolic acid end-products using calcium
and magnesium carbonates stored in their bone, particularly their shell.
Other species (anoxia-intolerant) do not have this capacity and must avoid
hibernacula that might become anoxic to survive the winter months.
Hatchling turtles of all species studied to date are born with low bone content
and low buffer stores. As such, these animals will have a reduced capacity to
survive harsh winters unless they quickly accumulate the buffers necessary
or avoid those hibernacula likely to become anoxic. We analyzed hatchling
Red-eared slider turtles (an anoxia-intolerant species) for shell bone content.
We measured [Ca 2+ ], [Mg 2+ ], [K + ], [Na + ], and [CO 2 ] to determine if the
hatchlings for these animals start out similarly to other species. We
hypothesized that hatchling Red-eared slider turtles would lack sufficient
bone content and buffer stores after hatching to withstand entry into a
hypoxic or anoxic environment. We compared these results to hatchlings of
known anoxia-tolerant and anoxia-intolerant species as well as to adult
painted turtle shell content.
P3.28 REHOREK, S.J.; HILLENIUS, W.J.*; LEIGH, C.; FIRTH, B.T.; Slippery
Rock Univ., College of Charleston, Univ. of Adelaide, Univ. of Adelaide;
[email protected]
The anterior orbital glands in Sminthopsis crassicaudatis: a
nomenclatural conundrum
The anterior orbital glands of tetrapods include the Harderian and nictitans
glands, both located in the nictitating membrane. Usually these can be
differentiated either anatomically (nictitans gland is more anterior) or
histochemically (Harderian gland secretes lipids). However, conflicting
statements exist in the literature about the presence of these glands. For
example, of the two studies on Sminthopsis crassicaudata (Dasyuridae;
Marsupiala), one failed to note any anterior ocular glands and the other used
no histochemical analyses. This study reexamined the structure of this
glandular complex of S. crassicaudata. Histological examination revealed a
well-developed, two-part (anterior vs posterior) glandular structure in the
nictitating membrane. Histochemically and ultrastructurally it was shown that
secretions of both glandular portions are mainly serous with sparse lipid
droplets. The nomenclature of this complex depends upon the definition
used. According to the anatomical definition, S. crassicaudata would have
two glands: an anterior nictitans and a posterior Harderian gland. Fetal
examination will be required to confirm that distinction. In contrast, the
histochemical definition holds that both masses are Harderian glands, as
both produce lipid and appear to use a merocrine secretory mechanism.
However, the histochemical definition faces problems with respect to the
mechanism of secretion, multiple secretions and glandular plasticity.
Alternatively, the unitary definition refers only to the medial position of this
gland and allows for multiple unconnected ducts. Based on this definition, S.
crassicaudata would have one bilobed gland with an anterior and a posterior
lobe. This last definition is broad enough to account the level of anatomical
variation in the anterior ocular glands of tetrapods.
P3.216 REICHARD, J.D.*; FELLOWS, S.R.; KUNZ, T.H.; Boston University;
[email protected]
Thermoregulation during Flight in the Brazilian free-tailed Bat
Body temperature (Tb) is intimately linked to an animals form and function.
Although flight permits bats to forage over large areas, metabolic heat
produced as a byproduct of flight may lead to hyperthermia that can inhibit
metabolic pathways or damage tissues. Body surface temperatures (Ts) of
free-ranging Brazilian free-tailed bats, Tadarida brasiliensis, were measured
with infrared thermography over a range of ambient temperatures (Ta). Mean
T s was determined for the body, head, wings, and tail membrane during
emergence flights at dusk and during return flights at midnight and dawn. Ts
increased with Ta for all body regions (p<0.0001). At dusk, only the body was
0.06C warmer than Ta; all other regions were cooler. During midnight return
flights, the body and head were warmer than T a by 1.3C and 0.8C,
respectively. Wings and tail were both 1.0C below Ta. Similarly at dawn, the
body and head were 1.2C and 0.6C above Ta, respectively, and the wings
and tail were each 2.1C below T a. Cool membranes may result from bats
flying in cool air immediately prior to measurements or from evaporative
cooling. Mean internal Tb decreased between emergence flights (36.8C) and
return flights (34.4C). However, Tb increased from 5.4C to 9.0C above Ta
between emergence and return flights, suggesting increased heat production
during this time. The sides beneath the wings were the warmest body
regions, providing high potential for heat loss. At ground level, cool wings
would not facilitate heat dissipation. By shunting blood away from naked
wings during flight, bats reduce potential water loss that would otherwise
result from blood flow to these membranes. At the same time, warmer
regions on the body dissipate heat from flight muscles.
P2.136 REIN, R.*; WEIGAND, K.L.; DEAROLF, J.L.; Hendrix College,
Conway, AR; [email protected]
Do prenatal steroids affect maternal breathing muscles?
Prenatal steroids are administered to expecting mothers who begin to go into
labor prematurely in order to quickly develop the lung tissue of their fetuses.
Previous research has shown that exposure to these steroids has caused
atrophy of adult muscles, including diaphragm. Thus, we hypothesize that
exposure to prenatal steroids will cause atrophy of maternal muscle fibers,
specifically in four breathing muscles: the diaphragm, scalenus, rectus
thoracis, and rectus abdominus. Pregnant guinea pigs (Cavia porcellus) were
injected twice weekly for three weeks with betamethasone (0.5 mg/kg body
weight at 65%, 75%, and 85% gestation) or sterile water. Samples of all four
muscles were collected from treated and control adults and prepared for
histochemistry. Sample sections were cut in a cryostat and stained for
myosin ATPase. The diameters of twenty-five fibers of each type (fast and
slow twitch) were measured using Scion Image, and the data were compared
across treatment groups. The fast twitch fibers in the treated scalenus (41.5
+/- 4.0 m) and rectus thoracis (45.5 +/- 3.8 m) were smaller than their
respective controls (42.2+/- 3.8 m; 47.8 +/- 1.6 m). In addition, the slow
twitch fibers in the treated rectus abdominus (53.5 +/- 2.8 m) were smaller
than those in the control muscles (57.1 +/- 1.3 m). Thus, the effects of steroid
exposure seem to be muscle and fiber type specific. However, no significant
differences were found between the treated and control fiber diameters in all
four muscles. These results demonstrate that exposure to a prenatal steroid
caused no significant fiber atrophy in the four breathing muscles and suggest
that the maternal muscles are receiving little to none of the steroid, which is
all being delivered to the fetus as desired.
e296
P2.137 REISER, PJ*; BICER, S; Ohio State University; [email protected]
Distinct Sarcomeric Protein Isoform Differences in Mammalian Fast and
Slow Muscle Fibers are Associated with Muscle of Origin
We previously reported the existence of a novel slow fiber type ("S1F") in
limb muscles of mammalian species with relatively large adult body mass
(Bicer & Reiser, J. Muscle Res. Cell Motil., 25:623-633, 2004). These fibers
express slow-type myosin heavy chain (MHC-I) and slow-type myosin light
chains 1 and 2 (MLC1S, MLC2S), as well as fast-type MLC1 (MLC1F) and
variable levels of fast-type MLC3. Conventional slow fibers in the same
species express exclusively slow-type MHC and MLC isoforms. We also
reported (Reiser & Bicer, Biophys. J. 94:2301-Pos, 2008) characteristics of
"F1S" fibers, common in species with low adult body mass (e.g., rodents)
that, unlike conventional fast fibers which express exclusively fast-type MHC
and MLC isoforms, express MLC1S, along with fast-type MHC and MLC
isoforms. We now report that there are multiple subtypes of S1F fibers and of
F1S fibers, that differ from each other with respect to the level of expression
of specific sarcomeric protein isoforms, and these differences are
consistently associated with their muscle of origin. S1F fibers isolated from
dog gastrocnemius and tibialis cranialis differ from each other with respect to
the relative level of S1F: ~7% and 40%, respectively, of total essential MLC
(i.e., MLC1 + MLC3). F1S fibers in rat gastrocnemius and tibialis cranialis
consistently differ from each other with respect to the expression of fast-type
isoforms of troponin-T. These results reveal even greater complexity in
patterns of sarcomeric protein isoform expression and in the distribution of
fiber types in mammalian limb muscles than previously recognized. Possible
influences of these differences in isoform expression on functional properties
will be discussed. Supported by the National Science Foundation.
P2.174 REITZEL, Adam M*; FINNERTY, John R; TARRANT, Ann M; Woods
Hole Oceanographic Institution, Boston University; [email protected]
Taking the heat: organismal and molecular responses of the estuarine
sea anemone Nematostella vectensis to thermal stress
Increasing global temperatures represent a threat to estuarine natives that
are limited in their ability to disperse to more suitable habitats. Global
warming is increasing the extremes of temperature in estuaries creating even
larger ranges that resident taxa must respond to. At the same time, estuaries
have become increasingly fragmented by extensive coastal development,
some of which interrupts the natural hydrological circulation. Nematostella
vectensis, an anemone occupying tidally restricted marsh pools throughout
North America, is a representative of high marsh taxa that are likely to be the
most heavily effected organisms due to their isolation. We first studied the
role of temperature in individual growth with common-garden experiments
which showed: 1) temperature has a large effect on growth rates, and 2)
individuals from different parts of N. vectensis' range show differential
responses to high temperatures consistent with local adaptation along a
latitudinal gradient. Second, we report on the development and utility of
quantitative PCR to quantify expression of heat shock genes in response to
temperature stress. Our data suggest that N. vectensis has adapted to local
temperatures along its extensive range and that heat shock proteins provide
a valuable molecular marker for assessing individual responses to warming
temperatures.
P3.154 REYNA, K.S.; University of North Texas; [email protected]
Acoustic signaling and temperature variations: their effects on the
physiology and hatching synchrony of the developing avian embryo
Hatching synchrony is a strategy utilized by some oviparous vertebrates to
maximize hatchling survival particularly in threatening environments. In many
precocial birds hens lay one egg per day until their clutch is complete (laying
asynchrony) yet members of the clutch hatch within a short period of time
(typically within 10% of incubation time; i.e., hatching synchrony). Various
laboratory studies attribute this phenomenon to acoustic signaling among
adjacent embryos; however, no investigation has been done under simulated
natural conditions. In quail species, and most distinctly in the Northern
bobwhite (Colinus virginianus), the time difference between the first and last
egg laid is typically 14 days. In the northern portion of the bobwhites range it
is believed that embryos experience developmental diapause or torpor as
ambient temperatures rarely exceed physiological zero (24C) during the
pre-incubation period. However, in their southern range nest temperatures
have been shown to exceed incubation temperature for most of the day,
indicating that development must be occurring during the pre-incubation
period. Accordingly, earlier laid embryos must synchronize their development
with later laid embryos in order to hatch simultaneously or developmental
asynchrony might occur in spite of hatching synchrony. I hypothesize that
acoustic signaling among embryos of a clutch stimulates later laid eggs to
accelerate development by increasing heart and metabolic rate; however,
due to high temperatures experienced during the pre-incubation period I
speculate that embryos will exhibit developmental asynchrony at the time of
hatching. Underdeveloped hatchlings may be more prone to predation or
less fecund leading to population declines.
P2.72 RIVERA, A.R.V.*; WYNEKEN, J.; BLOB, R.W.; Clemson University,
Florida Atlantic Unversity; [email protected]
Conservation of muscle activation patterns in the forelimbs of
swimming turtles: A comparison of three lineages (Trionychidae,
Emydidae, Cheloniidae)
Tetrapod limbs exhibit a diverse range of forms. Correlated with the evolution
of this diversity, new locomotor styles might arise through changes in
anatomy, changes in the patterns of muscle activation that produce limb
motion, or some combination of both. Turtles are an excellent lineage in
which to test for such changes because of their diverse locomotor styles and
morphologies. Although most freshwater turtles swim using asynchronous
anteroposterior rowing motions of the limbs, sea turtles swim via
synchronous dorsoventral flapping of forelimbs modified as flippers. To test
how such different forelimb motions are produced among groups with
generally similar muscle arrangements, we compared high-speed video and
electromyographic (EMG) data from swimming softshell turtles (Apalone
ferox, an aquatic specialist from the basal trionychid clade) and red-eared
sliders (Trachemys scripta, a generalized Emydid) to data from the derived,
flipper-shaped forelimbs of loggerhead sea turtles (Caretta caretta). Despite
being aquatic specialists and possessing extensively webbed forelimbs,
softshell turtles show muscle activation patterns and kinematics that
generally resemble those of sliders. Some differences emerge between
these species and sea turtles, but all three species also show markedly
similar motor patterns for some forelimb muscles despite their kinematic
differences. These data indicate that some motor patterns have been
conserved in the evolution of turtle limb function despite major evolutionary
changes in anatomical structure.
e297
P1.37 RIVERA, G/J*; TURNER, T; WALTERS, L/J; University of the Virgin
Islands, University of Central Florida; [email protected]
Feeding Behavior of Juvenile Diadema antillarum, the Long-Spined
Black Sea Urchin
Diadema antillarum play an important role in the coral reef community as a
keystone grazer. As such they eat algae which compete with coral for space
on the reef. Their grazing maintains algal density to a low level allowing
corals to flourish and facilitating the recruitment of new corals. However, in
the early 1980s there was a Caribbean wide die-off of Diadema caused by a
still unknown pathogen removing 99% of the population. This created the
opportunity for macroalgal cover on reefs to increase. Thus, the return of
Diadema to reefs is important, but the feeding preference of the juvenile
urchin (< 2 cm) is uncertain. Recent availability of the juvenile urchin in
Brewers Bay, St. Thomas, US Virgin Islands allowed for an assay to assess
feeding preferences. Five trials were conducted, each with 30 juvenile
urchins, and each urchin was fed a single algal thallus for five days. Trials
tested: the red alga <i>Acanthophora spicifera , the brown algae Dictyota
menstrualis and Lobophora variegata, the calcified green alga Halimeda
opuntia, and the uncalcified green alga Caulerpa macrophysa. Juvenile
urchins had distinct significantly different preferences (Kruskal-Wallis, p
<0.001): they ate large amounts of <i>Acanthophora and Caulerpa but much
less of the other species. This information may help managers wishing to
return urchins to reefs. Funded by NIH MBRS-RISE Grant # GM6132, NSF
HBCU-UP
P2.100 RIVERA, G.*; MCGILL, R.T.; RIVERA, A.R.V.; BLOB, R.W.; Clemson
University, South Carolina Governor's School for Science and Mathematics;
[email protected]
Variation in shell shape of flattened and loggerhead musk turtles
The flattened musk turtle (Sternotherus depressus) and the loggerhead musk
turtle (Sternotherus minor) are closely related species within the family
Kinosternidae. While these species can have similar color patterns and are
similarly sized, they display distinct shell morphologies, with the carapace of
S. depressus being flattened in comparison to S. minor. This variation in
shape has been attributed to differences in habitats and anti-predator
behaviors, particularly the presence of and preference for sheltered crevices.
Sternotherus depressus is endemic to the Black Warrior River Basin of
Alabama and inhabits shallow fast-flowing water with rocky substrates. In
contrast, S. minor inhabits slow-flowing water with sandy bottoms and is
found throughout Alabama and other southeastern states, but is excluded
from the Black Warrior River Basin. Although it is well established that shell
shape differs between these species, it is not clear if these distinctions are
equally prominent for both sexes, or if they are maintained throughout growth
to adult size. To examine these questions, we used geometric
morphometrics to compare differences in three-dimensional shell shape of
Sternotherus depressus and Sternotherus minor for both sexes over a range
of sizes. Interspecific differences in shell shape were significant for both
males and females; however, males of the two species converge in shape
with increasing size. Such convergence in shape might reflect a preference
for similar habitats among larger males of these species.
P2.67 RIVERA, A.R.V.; BENNETT, N.L.*; RIVERA, G.; WYNEKEN, J.;
BLOB, R.W.; Clemson University, Florida Atlantic University;
[email protected]
Whole-body acceleration during swimming in the green sea turtle
(Chelonia mydas): A comparison of upstroke and downstroke
Sea turtles are distinctive among aquatic turtles in terms of how limb
morphology and limb mechanics interact to produce thrust, the force
responsible for forward movement during swimming. Sea turtles swim using
synchronous, dorsoventral movements of modified forelimbs (i.e., elongated
flippers) to propel themselves through water. These patterns resemble the
flapping motions of flight and have been hypothesized to produce thrust
during both the upstroke and downstroke segments of the limb cycle.
However, to date, it is unknown whether both phases of the limb cycle
contribute equally to forward propulsion. To compare the relative
contributions of upstroke and downstroke to forward motion in swimming sea
turtles, we analyzed high-speed video of rectilinear swimming by juvenile
green sea turtles (Chelonia mydas). Maximum whole-body acceleration is
considerably higher during downstroke than during upstroke. Additionally,
forward displacement of the turtle does not differ significantly between
upstroke and downstroke, even though downstroke is significantly shorter in
duration than upstroke. These patterns are likely related to the production of
greater average and peak accelerations of the flipper during downstroke,
which are facilitated by the hypertrophied pectoralis muscles of sea turtles.
P1.88 RIVERA, F. M.*; SOTO, W.; NISHIGUCHI, M. K.; New Mexico State
Univeristy, Las Cruces; [email protected]
Allelopathy in the symbiotic bacterium Vibrio fischeri; competitive
exclusion prior to or during host infection?
Many interactions exist between large varieties of organisms, including
bacteria that are found in free-living habitats. One type of interaction is
allelopathy, which is the process of organisms excreting chemical
substances to inhibit or kill closely related strains or species. Bacteria have
the capacity to use allelopathic behavior for mechanisms such as infection,
colonization, and competition. Specifically, symbiotic associations that harbor
environmentally transmitted bacteria have the ability to promote this type of
behavior between competing strains prior to or during colonization. In this
study, we are testing whet specific strains of the squid symbiont Vibrio
fischeri, experience antagonistic relationships as a result of exudate
productions and/or milieu alterations that inhibit growth. We have used a
series of cross inoculations between competing V. fischeri strains with spent
media to determine whether certain strains are promoting any type of
allelopathy. Results from previous research indicate that bacterial species do
have an effect upon the growth of competing strains, and that specific
substrates induce luminescence of V. fischeri, suggesting that intraspecific
interactions occur prior or during the infection of squid light organs.
Understanding the mechanisms of Vibrio allelopathy will provide insight as to
why such genetic diversity exists among Vibrio symbionts, and whether their
ecology is determined by both abiotic and biotic factors. Furthermore, this
study may lead to the identification of certain chemical compounds produced
by V. fischeri that contain properties to inhibit other Vibrio bacteria, including
strains that are harmful to fisheries or pathogenic to organisms.
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P2.51 RIVERA, Ajna; OAKLEY, Todd*; University of California, Santa
Barbara; [email protected]
Eye development in a sexually dimorphic species of ostracod
(Crustacea)
One of the standout questions in evolutionary biology is the novelty question:
How do new features evolve? In a broad sense, this question explores how
similar genomes can make different phenotypes. One way to look at this is to
examine sexually dimorphic species, where nearly identical genetic
backgrounds can make radically different organs. To this end, we are
studying the philomedid ostracods (Crustacea). The Philomedidae nearly all
have at least a simple median eye but also exhibit a wide array of lateral eye
sizes. These range from completely absent in Igene, to huge compound eyes
in Euphilomedes carcharodonta. We present a phylogeny showing that loss
of eyes occured several times and gain of eyes is also likely. On top of this is
a pattern of extreme sexual dimorphism which has also likely to have been
lost and gained several times. In dimorphic species, females have
rudimentary eyes while males have compound eyes with up to 33 large
ommatidia. We examine the development of 3 philomedine species native to
California E. morini, E. carcharodonta, and E. longiseta. In these species,
male eyes appear to arise via a tissue furcation event male eye tissue splits
or doubles to form a stagnant rudimetary field homologous to the female eye
and a fast growing ommatidial field. This suggests that novel features can be
gained by tissue duplication events. In this scenario, the duplicated tissue
can now follow a new evolutionary trajectory, analogous to the gene
duplication and neofunctionalization model of gene evolution. To examine
the potential trajectory of a duplicated tissue, we compare gene expression
between male and female E.morini during eye development.
P2.180 ROCCA, Kyle AC*; GRAY, Emilie M; BESANSKY, Nora J; University
of Notre Dame; [email protected]
Thermotolerance of alternative 2La karyotypes in Anopheles gambiae
The primary malaria vector in Africa, Anopheles gambiae, is also well known
for its ability to adapt to diverse climates and anthropogenic environments.
Alternative chromosomal arrangements allow habitat expansion, exemplified
by the polymorphic inversion 2La/2L+a. Field 2La frequencies reach 100% in
arid savannas, while the 2L+a arrangement is predominantly found in humid
environments, implicating 2La in aridity tolerance. As ability to survive high
temperature exposure is an essential component of aridity tolerance, we
have conducted a study of thermotolerance in two colonies of mosquitoes
dissimilar solely in 2La arrangement. We hypothesize that the colony with the
2La inversion will perform better in measures of thermotolerance. This is one
of two meeting papers comparing stress resistance in the 2La/2L+
populations (see Gray, Rocca and Besansky). We subjected 4th instar larvae
and pupae to a heat stress (40oC water bath) for 30 to 180min and assessed
survival as well as pupation success of the stressed larvae. We found that
larvae responded similarly to thermal stress but that, surprisingly, 2L+ pupae
were overall more thermotolerant than 2La pupae. We also tested the effect
of heat hardening (HH, 1h at 38 o C) on thermal tolerance of larvae and
pupae. We found that, in 2La, HH significantly improved survival but not
subsequent pupation success of stressed larvae. In both colonies, HH had
little effect on survival of stressed pupae. Preliminary thermotolerance
measurements on adults suggest no difference at this life stage. These
intriguing results will be discussed in terms of evolutionary fitness advantage,
and the methodology can guide further study relating genetic differences and
physiological traits.
P3.200 RODRIGUEZ, E.I*; SAUNDERS, K.; DAVIS, G.; SHUSTER, S.M.;
AYERS, T. J; Northern Arizona University, Univ. of Florida, Univ. of
Maryland, Baltimore Medical School; [email protected]
A Molecular Phylogeny for the Thermosphaeroma Species Complex
The genus Thermosphaeroma (Crustacea:Isopoda:Sphaeromatidae)
consists of 7 described freshwater species endemic to thermal springs in
Texas and New Mexico in the United States, as well as in Chihuahua,
Durango, Coahuila and Aguascalientes in the Republic of Mexico. The
easternmost described species of the genus, T. subequalum, is found in at
least 9 thermal springs located on both sides of the Rio Grande River over a
150 km distance. We used an approximately 470 base pair sequence from
the mitochondrial 16S ribosomal RNA gene to investigate evolutionary
relationships among these populations. Our analysis included sequences
from mulitiple individuals from all known Thermosphaeroma species and
populations, as well as from 4 other species belonging to 2 currently
recognized Sphaeromatid subfamilies, the Dynameninae and the
Sphaeromatinae. Our results provide (1) a molecular phylogeny for the
genus Thermosphaeroma, (2) biogeographic data useful for studies of North
American post-Cretaceous organisms, (3) support for the hypothesis that the
Sphaeromatinae and the Dynameninae represent distinct Sphaeromatid
lineages, and (4) evidence that Thermosphaeroma belongs within the latter
subfamily.
P2.92 ROGERS, Nala/L*; CARRIER, David/R; Univ. of Utah, Salt Lake City;
[email protected]
Sexual dimorphism in skeletal proportions of California voles
The genus Microtus (voles) is ideal for studying sexual selection because it
contains several closely-related species with diverse mating strategies. We
hypothesized that polygynous species will show sexual dimorphism in body
proportions due to functional tradeoffs for aggressive male-male competition
versus locomotion. For example, we expected polygynous males to have
more robust skulls, thicker limb bones, and greater mechanical advantage at
their limb joints. To test this hypothesis, we measured skeletal metrics on
male and female California voles (Microtus californicus) and looked for
differences in proportions while controlling for body size. The males of this
polygynous species are approximately ten percent heavier than the females.
Contrary to our expectations, we found no sexual dimorphism in the
postcranial skeletal proportions. There was dimorphism in the skull, but the
direction was opposite to our predictions; for their size, females had larger
skulls. There are several possible explanations for this result. First,
proportions that are advantageous for fighting may be so maladaptive for
other purposes that they are not selected for even among polygynous males.
Second, the same body proportions could be advantageous for both fighting
and locomotion, so that specialization for fighting does not lead to a
difference in shape. Finally, females might need to fight in order to guard
against infanticide. In this case, both sexes would be specialized for fighting.
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P3.10 ROMEO, M.R.*; FURIMSKY, M; Westminster College, Pennsylvania;
[email protected]
Teratogenic Effects of Ethylene Glycol and 5-methyl-1H-benzotriazole
on Zebrafish Central Nervous System Development
More than 50 million liters of aircraft deicer and anti-icer fluids (ADAFs) are
used annually in North America. ADAFs contain glycols that serve as
freezing point depressants and benzotriazoles that act as corrosion
inhibitors. Components of ADAFs are known to make their way into aquatic
ecosystems, but they are generally harmless to adult fish; however, very little
is known about their effects on developing fish. Therefore, we investigated
the specific effects of the ADAF additives ethylene glycol (EG) and
benzotriazole (BT) on zebrafish embryos to determine whether these
chemicals had a teratogenic effect on fish visual system (VS) development.
Eye surface area was measured at 48 hours post-fertilization (hpf) following
exposure of zebrafish eggs to different concentrations of EG and BT.
Mortality rates with EG treatment alone were relatively low at concentrations
less than 2.5% EG, but 100% mortality was observed at 5% EG. In BT-only
treatment groups, mortality followed a dose-dependent pattern, with 100%
mortality observed at 0.1 mg/ml BT. In terms of ontogenic effects, 2.5% EG
severely depressed VS development, leaving the eyes at 50% of their normal
surface area at 48 hpf. Measures of eye surface area following BT exposure,
however, had a less severe impact on VS development, with eye surface
area being decreased by 12% and 16% at BT concentrations of 0.025 mg/ml
and 0.05 mg/ml, respectively. Exposure to EG and BT, in combination,
suppressed VS development to a greater degree. Thus we conclude that
high levels of dissolved ethylene glycol and benzotriazole do affect survival
in embryonic zebrafish, and sub-lethal doses do indeed have teratogenic
effects that can be detrimental to the overall health of fish populations.
P2.194 RONGES, Daria*; WALSH, Jillian; STILLMAN, Jonathon; SINCLAIR ,
Brent; Daria Ronges, San Francisco State Univ., CA , Jillian Walsh, The
Univ. of Western Ontario London, Canada , Jonathon Stillman San Francisco
State Univ., CA , Brent J. Sinclair, The Univ. of Western Ontario London,
Canada; [email protected]
Membrane Composition and Gene Expression During Thermal
Acclimation in Porcelain Crabs
Petrolisthes cinctipes is a temperate mid-intertidal crab species that can
experience wintertime habitat temperatures below the freezing point of
seawater. Thermal acclimation to 8°C induces enhanced cold tolerance
relative to crabs acclimated to 18°C. We have investigated alterations in
membrane composition and gene expression that accompany the first 24
hours of physiological acclimation to cold. Crabs were collected from the field
and held in aquaria at 12°C, the water temperature at the time of collection.
The experiment was initiated by transferring crabs to aquaria held at one of
three temperatures: 8°C, 12°C, and 18°C. At time points during the first 24
hours of acclimation crabs were exposed -3°C for one hour, and then
allowed to recover at their acclimation temperature. Most of the 8°C
acclimated crabs survived more than 36 hours after the cold shock, while
warm-acclimated crabs did not. To examine acclimation-related changes in
lipid composition and/or gene expression, heart tissues of crabs acclimated
to 8°C or 18°C, and were dissected at each time point and used for analysis
of membrane composition or RNA extraction for cDNA microarray analysis.
Supported by NSF ESS 0533920 to JHS and a University of Western Ontario
Academic Development Fund grant to BJS.
P3.47 ROSENBLUM, H.G.*; GUTIERREZ, A; ROBERTS, S; HIROKAWA, J;
PORTER, M; LONG, J.H.; Vassar College; [email protected]
Character Evolution in Robotic Fish
We use robots to test adaptation hypotheses about the evolution of three
vertebrate characters: caudal fin span, number of vertebrae, and sensitivity
of the lateral line. Is it plausible that the evolution of these characters was
driven by selection for enhanced foraging and predator avoidance in a simple
predator-prey ecology? To address this question, we evolved ten
generations of a population of biologically-inspired, aquatic, and autonomous
robots. In each generation, each of six individual prey robots swam in three
trials, attempting to forage and, at the same time, avoid a pursuing predator
robot. Relative individual fitness was measured using a compound function
that rewarded faster cruising speed, greater escape acceleration, shorter
distance from the food source, greater distance from the predator, and larger
number of escape responses. Based on relative fitness, the top three
individuals were allowed to mate, with a genetic algorithm mutating the
genes, creating gametes, and making the new genotypes of the offspring.
We hypothesized that all of our characters would increase in magnitude,
evolving directionally and in concert, under constant selection. While caudal
fin span and number of vertebrae evolved in a positive direction, as
predicted, sensitivity of the lateral line appeared to undergo first stabilizing
and then disruptive selection. Thus it appears plausible that separate
characters can evolve both in concert and independently under a single
selection regime. This work was supported by NSF DBI-0442269.
P2.156 ROSENDALE, A.J.*; COSTANZO, J.P.; LEE JR., R.E.; Miami
University; [email protected]
Identification of an Aquaporin and a Facilitative Urea Transporter in
Rana sylvatica and Rana pipiens
During periods of osmotic stress, anurans must undergo various
physiological changes in order to prevent excessive dehydration. One such
physiological change is the reabsorption of water and solutes, such as urea,
from the urinary bladder, a process which recent evidence suggests is
facilitated by membrane transport proteins. Aquaporins and facilitative urea
transporters are two such transport proteins whose importance in the
retention of water and urea respectively is not yet fully understood. We used
the wood frog, Rana sylvatica, a terrestrial species, to investigate the
expression of an aquaporin (AQP-1) and a facilitative urea transporter that
were cloned from the urinary bladder. For comparative purposes, we ran
parallel experiments on a less terrestrial species, R. pipiens. Both proteins
showed a high degree of homology to previously reported anuran
transporters, with the aquaporin being homologous to the mammalian
AQP-1, and the urea transporter being homologous to the mammalian
UT-A2. Quantitative real-time PCR was performed on multiple tissues with
the mRNA expression of these transporters being highest in the bladder and
kidney. We analyzed the expression of these transporters at the protein level
with western blot techniques, using an antibody designed against a known
urea transporter (fUT) from R. esculenta and a mammalian AQP-1 antibody.
Consistent with our mRNA findings, expression of these transporters was
highest in the bladder and kidney. Results of our study confirmed the
presence of an aquaporin and facilitative urea transporter in R. sylvatica and
R. pipiens and laid the foundation for future studies aimed at elucidating their
role in the physiological regulation of water and solute management in
amphibians. Supported by NSF grant IAB 0416750.
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P1.14 RUIZ, M.*; DEMAS, G.E.; MARTINS, E.P.; Indiana University,
Bloomington; [email protected]
Experimentally elevated testosterone suppresses immunity in
food-limited sagebrush lizards
Testosterone (T) has been shown to increase reproduction and decrease
immunity in many cases. Yet, although reproductive investment decreases
immune function, supplemental feedings can eliminate this effect. In this
study, we considered the effect of food availability and T on immune function
and reproductive behavior in sagebrush lizards to assess how T and energy
availability act to affect these trade-offs. We experimentally manipulated diet
and T of males in a natural population. We determined immune response by
calculating the bacterial killing capability of collected plasma exposed to E.
coli ex vivo. We measured reproductive behavior by counting the number of
courtship displays produced in a 20-min sampling period. Immune function
increased with supplemental feedings, a finding that was most pronounced in
lizards with increased T. Furthermore, T increased immunity in lizards with
additional food resources but not in lizards that were not supplemented.
Thus, we observe an interactive effect of food availability and T on immune
function. Although not significant, T exhibited a trend towards increasing
courtship displays. Thus, a trade-off between T and immunity was
suggested, but only when lizards were on a restricted diet. Food availability
diminished this effect; lizards with supplemental food were able to increase
both courtship rates and immunity in the presence of high T. Yet, in non
T-treated animals, this trade-off was not as pronounced. Collectively, this
study shows that the energetic state of the animal plays a critical role in
modulating the interactions among T, behavior and immunity in sagebrush
lizards and likely other species.
P2.46 RUIZ-JONES, G.J.*; HADFIELD, M.G.; Chaminade University of
Honolulu, Honolulu; [email protected]
The dissociation of the apical sensory organ of Phestilla sibogae
during metamorphosis
The apical sensory organ of Phestilla sibogae undergoes radical
morphological changes during metamorphosis. At the beginning of
metamorphic induction (1 hour) the ASO is complete with 5 serotonergic
neurons (2 type II parampullary and 3 type I parampullay) and 5 ampullary
neurons filled with sensory cilia. As metamorphosis proceeds the ASO and
serotonergic nerve fibers originating from the ASO that innervate the velum
begin to dissociate. The 5 serotonergic neurons of the ASO are no longer
present once the velum is lost. The 5 ampullary neurons of the ASO appear
morphologically different by the third hour of metamorphosis. By the eighth
hour of metamorphosis the ampullary neurons have lost their connections
and begun to dissociate. It is evident that by the third hour, in larvae that
have lost their velum, the ASO no longer exists. However, it is interesting
that the ASO does persist up to the eighth hour of metamorphosis in larvae
that have not lost their velum.
P3.155 RYCROFT, N*; WELLS, S; MCCONAUGHA, J; Old Dominion
University; [email protected]
Correlation Between Female Size and Egg Quality in the Chesapeake
Bay Population of Blue Crab, Callinectes Sapidus.
The ecologically important Chesapeake Bay blue crab, Callinectes sapidus,
has recently seen a decline in the population of the species. Previous
research has shown a breakdown of the allometric relationship between size
and fecundity of mature females. Examination of the eggs from the
2005-2006 spawning seasons showed large inter-annual variations in both
lipid and protein concentrations. The 2005 and 2006 data also showed a
decrease in lipid and protein concentrations in the eggs as the season
progressed. The intent of the study was to examine eggs from 2007
collections and compare the data to the 2005 and 2006 spawning seasons.
We hoped to further explain the breakdown of allometry by relating the
amount of lipids per egg to the size and weight of the female. Multiple
extractions were used to quantify the amount of lipids per egg while a
fluorescent plate reader was utilized to measure the protein concentrations.
The data shows that average weight of lipids per egg does not have a
significant relationship with the weight or size of the female. This does not
support the hypothesis that larger crabs which produce less than expected
eggs allocate more energy per egg in the form of lipids to help increase the
fitness of the larvae.
P1.127 SAMUEL, D.*; LAGARES, E.; CARROLL, M.A.; CATAPANE, E.J.;
Medgar Evers College; [email protected]
Identification and Distribution of Octopamine in Ganglia and Innervated
Organs of Crassostrea virginica
Octopamine is a biogenic amine which was first identified in the octopus. It
has been well studied in arthropods and a few gastropods serving as a
neurotransmitter and hormone. Octopamine has been rarely reported in
bivalves and not in Crassostrea virginica. We utilized HPLC to determine if
octopamine is present in ganglia and tissues of C. virginica. Biogenic amines
were measured by HPLC techniques with fluorescence detection. We used
an isocratic, ion-pairing HPLC analysis with fluorescence detection to
resolved norepinephrine, epinephrine, octopamine, dopamine and serotonin.
Cerebral ganglia, visceral ganglia, gill and palps were dissected, weighed,
homogenized, centrifuged, filtered and injected into a Beckman HPLC
system with a Phenomenex Gemini 5µ C18 column and a Jasco FP 2020
Spectrofluorometer. The mobile phase was 50 mM acetate buffer (pH 4.7)
with 1 mM EDTA, 1.1 mM SOS and methanol (85%/15%, v/v). Octopamine
was found in ng amounts in gill, palps, cerebral ganglia and visceral ganglia.
Endogenous octopamine levels were increase when animals were treated
with tyramine, an octopamine precursor. The octopamine peak was verified
by injecting samples spiked with standard octopamine. The study identifies
octopamine in the nervous system and innervated organs of C. virginica. The
physiological role of octopamine in C. virginica is not known as yet and
should be explored. This work was supported in part by grants
2R25GM06003-05 of the Bridge Program of NIGMS, 0516041071 of
NYSDOE, 0622197 of the DUE Program of NSF and 0420359 of the MRI
Program of NSF.
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P1.42 SAWYER, S. J; AVERY, T.*; Glenville State College, Southern Illinois
University Edwardsville; [email protected]
Investigation of integrins during pedal lacerate development in Aiptasia
pallida
Integrins are cell surface receptors that play a vital role in cell attachment
and are important signaling molecules in cell growth and tissue formation.
These proteins have been identified in Cnidarians but their distribution and
regulatory properties are not well understood. In this study we investigate the
functional role of integrins during pedal laceration in the Cnidarian, Aiptasia
pallida. During pedal laceration, small portions of the pedal disc are shed and
reorganize to form a complete sea anemone in 48-72 hours after initial
lacerate formation. This process must involve cell detachment and
rearrangement and so makes it an optimal model for studying integrin
signaling pathways. Through methods in immunocytochemistry and use of
pharmacological agents which disrupt functional integrin-signaling pathways,
we are studying the function of integrins during pedal laceration. Staining
untreated pedal lacerates with an anti-integrin antibody has shown
distribution of integrins centralized between the two primary epithelial layers,
throughout the outer tissue layers and within the striated cortex of the
mesoglea. Treating pedal lacerates with pharmacological agents suggests
that integrin signaling pathways are involved in the development of the pedal
lacerate. Treating lacerates with the PI3K pathway inhibitor LY 294002 (12M)
and MAP kinase inhibitor PD98059 (20M) cell maturation inhibited
development in 60% of the lacerates. When treated with the PI3K pathway
activator SC3036 (24M) pedal lacerates showed accelerated development
rate with treated animals maturing 50% faster than untreated controls. We
are now looking at how disrupting integrin signaling pathways affects the
integrin staining of treated pedal lacerates and adult animals to gain a more
complete understanding of how pedal lacerate development is modified.
P3.164 SCHMIDT, Kim L*; CHIN, Eunice H; SHAH, Amit H; SOMA, Kiran K;
Univ. of British Coulmbia, Trent Univ., Michigan State Univ.;
[email protected]
Cortisol and corticosterone in the avian immune and nervous systems
during development
Glucocorticoids (GCs) have important effects on the developing immune and
nervous systems. In addition to being synthesized by the adrenal glands,
GCs may be synthesized in extra-adrenal tissues, including the immune
system and brain. In developing zebra finches, cortisol levels in the immune
system are higher than cortisol levels in plasma, and cortisol (not
corticosterone) is the predominant GC in the immune system (Schmidt and
Soma, 2008). To date, little is known about how local GC production differs
among species and how it varies with life history strategy. Songbirds provide
the opportunity for comparative studies of local GC production. Here, in study
1, we measured cortisol and corticosterone in the plasma, immune system
(bursa, thymus, spleen) and brain of European starlings at post-hatch day 0
(P0) and P10. Subjects were sampled within 3 min or after 45 min of
restraint. In study 2, we directly compared local GC levels in zebra finches
and starlings at the same age. Steroids were extracted using solid phase
extraction and quantified using specific and sensitive immunoassays.
Surprisingly, in study 1, GC levels in the immune system were comparable to
GC levels in the plasma of starlings. GC levels in the brain were lower than
GC levels in plasma. Restraint increased local and systemic GC levels at
P10, but not at P0. In study 2, in zebra finches, cortisol was the predominant
GC in the immune system, and cortisol levels in the immune system were
higher than cortisol levels in plasma. In starlings, cortisol levels were lower in
the immune system, suggesting a species difference in local cortisol
synthesis. In both species, GC levels in the brain were low. These results
suggest a species difference in systemic and local GC levels, which may be
due to differences in the life history strategies of zebra finches and starlings.
P3.50 SCHOENFUSS, HL; ROOS, JD; RIVERA, ARV; BLOB, RW*; St.
Cloud State Univ, MN, Clemson Univ, SC, Clemson Univ, SC;
[email protected]
Motor Patterns of Distal Hindlimb Muscles in Walking Turtles:
Implications for Models of Limb Bone Loading
Previous studies indicate that the ground reaction force (GRF) in walking
turtles exerts a flexor moment at the ankle during stance. As a result,
extensor muscles must be active to counter the GRF. Of four proposed ankle
extensors in turtles, two (gastrocnemius medialis and pronator profundus)
originate on the tibia and fibula respectively, while the other two (flexor
digitorum longus, gastrocnemius lateralis) originate from the distal femur,
crossing the flexor side of the knee and potentially eliciting antagonist forces
from muscles on the extensor surface of the femur that could contribute to
femoral stress. Current bone stress models assume that all four muscles are
active. However, if only ankle extensors crossing the knee were active during
stance then femoral stresses might be higher than predicted, whereas if only
those not crossing the knee were active then stresses might be lower. We
recorded EMGs from the four turtle ankle extensors during treadmill walking
to test which need to be incorporated into bone stress models. Analysis of
synchronized footfall and EMG patterns revealed that all four muscles were
active during at least part of the stance phase, corroborating previous bone
stress calculations. However, functional differentiation among these muscles
is evident with, for example, the two heads of the gastrocnemius exhibiting
second activity bursts during swing phase, and flexor digitiorum longus
activity persisting through stance phase into the beginning of swing phase.
These subtle distinctions in muscle contraction patterns among these four
ankle extensor muscles indicate the potential for considerable flexibility in the
control of distal hindlimb motion in turtles. Supported by NSF IOB-0517340.
P1.108 SCHOLNICK, D. A.*; MANIVANH, R. V.; SAVENKOVA, O. D.;
Pacific University, Oregon, Pacific Unversity, Oregon;
[email protected]
THE PHYSIOLOGICAL CONSEQUENCE OF MALARIA INFECTION IN
THE WESTERN FENCE LIZARD, SCELOPORUS OCCIDENTALIS.
We examined the influence of reduced hemoglobin concentrations resulting
from malaria infection on thermoregulation and metabolism in the Western
fence lizard, Sceloporus occidentalis. Malaria infections diminish the oxygen
carrying capacity of the blood, depressing hemoglobin concentrations by as
much as 25% in lizards. Western fence lizards collected from central and
southern Oregon were screened for Plasmodium mexicanum. Malaria
infected and uninfected lizards were placed in a temperature controlled
treadmill at preferred body temperature (34.5 o C) and induced to walk at
constant speed for 5 minutes (0.7 m min-1) or sprint maximally to exhaustion
(< 2 min of activity). Malaria infection significantly increased preferred body
temperature in a thermal gradient following sustained activity (2 to 4 o C
increase; ANOVA P < 0.05) but had little impact on thermoregulation
following exhaustive exercise. There was a strong negative correlation
between hemoglobin concentration and post-activity body temperature but
no indication of post-exercise anapyrexia typically reported in oxygen limited
lizards. Excess oxygen consumption during recovery was about 40% higher
in infected lizards when compared to uninfected after similar levels of activity.
Malaria infection significantly elevated blood lactate following sprint or
endurance activity (20 and 36% elevation, respectively) when compared to
uninfected lizards. Our findings suggest that there are additional metabolic
costs, measured as excess oxygen consumption and thermoregulation
disruptions associated with malaria induced hemoglobin depression. These
results may help explain limited size and reproductive success previously
measured in malaria infected lizards.
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P3.101 SCHOLNICK, D. A.; HAYNES, V. N.*; SCHWEITZER, K. I.; Pacific
University, Oregon; [email protected]
HYPOXIA IMPAIRS ANTIBACTERIAL DEFENSE IN THE DUNGENESS
CRAB, CANCER MAGISTER
We examined the possibility that long-term decreases in environmental
oxygen (hypoxia), similar to those experienced by many coastal marine
crustaceans, can limit the ability of crabs to respond to indigenous bacteria in
the hemolymph and increase the rate of bacterial infection. Male Dungeness
crabs, Cancer magister, were collected off of the central Oregon coast and
maintained in UV sterilized seawater at 9oC. Crabs were exposed to either
50 or 100% air-saturated water for 72 h. Hemolymph was sampled every 24
h and levels of bacteria were measured as the total numbers of colony
forming units (CFU) present per mL of hemolymph. Immune response was
assessed as a change in the total number of circulating hemocytes and
granulocytes. Hemolymph lactic acid levels were measured to determine if
changes in bacterial infection alter levels of anaerobic metabolism in hypoxic
waters over time. Bacteremia increased after 24 h of exposure to hypoxia
and persisted for 72 h (P < 0.05; ANOVA). Colony forming units increased
from about 10 to over 4,000 per mL hemolymph during 72 of hypoxia. Crabs
exposed to air-saturation had no measurable change in CFUs over the
course of the experiment. The total number of circulating hemocytes were
unaltered by hypoxia for 48 h and showed only a small decrease after 72 h
(P < 0.05; ANOVA), consistent with a reduced capability to respond to
bacteria under low oxygen conditions. Exposure to hypoxia increased
hemolymph lactate levels only after 48 h suggesting that over time, elevated
bacterial concentrations may limit normal respiratory function. These results
suggest that low oxygen can suppress immune response and limit the crabs
ability to manage intrinsic bacterial levels.
P2.128 SCHROEDER, TP*; POWERS, DR; WETHINGTON, SM;
TOBALSKE, BW; George Fox University, Newberg, OR, University of
Montana, Missoula, MT, Hummingbird Monitoring Network, Patagonia, AZ;
[email protected]
Hovering Flight Performance in Captive and Free-Living Hummingbirds
Hummingbirds are tiny endothermic vertebrates and have high daily energy
requirements. Flight is energetically expensive and few studies have linked
flight-associated energy costs to daily energy budgets. Free-living and
captive hummingbirds were studied and their flight costs examined. Rufous
hummingbirds (Selasphorus rufus; ca. 3.3 g) were flown in a wind tunnel at
wind speeds from 0-10 m/s. Mean hovering metabolic rate (HMR) was 2.56
mL O2/min decreasing to 1.3 mL O2/min between 4-10 m/s. Mean HMR in
free-living Black-chinned hummingbirds (Archilochus alexandri; ca. 3.0 g)
and Broad-billed hummingbirds (Cynanthus latirostris; ca. 3.3 g) were 2.44
and 2.47 mL O2/min. HMR is nearly 2X more costly than forward flight and
HMR in the wind tunnel are comparable to those of free-living birds. The
metabolic power curve is not J shaped as previously hypothesized for
hummingbirds. Wing-disc loading (WDL) and wing-beat amplitude were
measured from calibrated images taken using high-speed video recordings.
Wing-beat amplitude during hovering for all birds ranged from 90-110
degrees per wing indicating less than maximal effort. WDL calculated using
our measured wing-beat amplitudes were for Black-chinned hummingbirds
(BC) males and females 7.95 and 7.00 N/m2, respectively. For Broad-billed
hummingbirds (BB) WDL was 5.57 N/m2 in males and 4.82 N/m2 in females.
These WDL values were 2X those calculated assuming maximal wing-beat
amplitude (360 degrees total). Our data suggest that even though hovering
flight is the most energetically costly activity exhibited by hummingbirds their
HMR is well below summit metabolism. Supported in part by NSF
IOB-0615648.
P1.8 SCHULER, Matthew S.*; LIMA, Steve L.; Indiana State University;
[email protected]
Why springs song is winters new friend: effects of urbanization on the
American robin (Turdus migritorius)
Global climate change is a growing concern among scientists and the
general public. Despite this concern, most researchers have failed to account
for the effects of local factors on climatic variation and its consequences for
the distributions of species. We studied the effects of urban environments on
the winter distribution of the American robin. We analyzed data across a
latitudinal gradient (25N to 65N) for 230 randomly selected cities in North
America. Average densities were based on the data from the Christmas Bird
Count between 2006 and 2008. A regression analysis was used to determine
whether the size of the human population affected the number of
overwintering robins. Slopes from latitudinal groups were analyzed starting at
25 to 30, ending with 60 to 65 to see if there was a greater city size effect in
northern latitudes. From our analysis, we concluded that larger cities affect
overwintering populations in northerly climates, because larger cities
maintain higher densities of robins during winter than small cities. Yet, this
phenomenon was not observed in southerly cities. Based on this analysis,
researchers should consider local environmental change when predicting the
effects on global change on the densities and distributions of organisms.
P1.85 SCHULER, Matthew S.; STORM, John J.; SEARS, Michael W.;
COOPER, Brandon S.*; WILLIAMS, Ben H.; ANGILLETTA, Michael J.;
Indiana State University, University of South Carolina - Upstate, Southern
Illinois University; [email protected]
Acclimation of thermal physiology in predictable and stochastic
environments: a test of optimality theory
Most environments vary stochastically, yet researchers rarely study the
phenotypic responses of organisms to stochastic environmental conditions.
Optimality models predict that stochastic environments favor generalists
while predictable environments favor specialists. If environmental conditions
change predictably between seasons, the optimal phenotype tracks the
environment by specializing for the conditions of each season. To evaluate
this theory, we exposed rough woodlice (Porcellio scaber) to four thermal
environments: a constant 20C, a constant 10C, a steady decline from 20 to
10C, and a stochastic decline that mimicked natural conditions. To control for
photoperiodic cues, the duration of photophase decreased according to the
natural environment. After 45 d, we measured several aspects of thermal
physiology, including the thermal sensitivity of locomotion, critical thermal
maximum, and chill-coma recovery time. We fit six nonlinear models to the
data and selected the best-fitting model using Akaikes information criterion.
Data were bootstrapped to obtain confidence intervals for thermal optima
and performance breadths. Contrary to our expectation, thermal treatments
did not affect the thermal sensitivity of sprinting; woodlice from all treatments
ran fastest at 33 to 34C and achieved > 80% of their maximal speed over a
range of 10 to 11C. Furthermore, woodlice exposed to stochastically and
predictably declining temperatures tolerated cold better than woodlice
exposed to a constant temperature of either 10 or 20C. These results cast
doubt on the assumptions of current models, suggesting the need to
examine genetic constraints on the evolution of acclimation.
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P3.189 SCHUMER, Molly E.*; RENN, Suzy C. P.; Reed College, Portland
OR; [email protected]
hCGH Detects Genomic Architecture Among African Cichlids Species
of the Genus Julidochromis
Cichlids are one of the largest and most diverse vertebrate families, and are
remarkable for their rapid radiation. Gene duplication has been identified as
a central method for rapid evolution, suggesting that it could play a role in the
rapid speciation and novel phenotypic traits found among cichlid species.
The genus Julidochromis is of particular interest due to distinct behavioral
traits such as sex-role reversal, cooperative brooding, and parental care that
vary between individual species. We have used microarrays from a closely
related species, Astatotilapia burtoni in order to identify duplicated and
diverged genes in four species of Julidochromis. These arrays allowed us to
profile the genetic variation between Julidochromis species, and identify
genes that have been duplicated or diverged in the Julidochromis family
compared to A. burtoni. As expected, there were fewer duplicated (45) than
diverged genes (355) when comparing A. burtoni to Julidochromis species,
and only a few species-specific duplications (5 for J. dickfeldi, 2 for J.
marlieri, 5 for J. ornatus, and 1 for J. transcriptus). These results are
currently being confirmed by quantitative real-time PCR and cloning for
sequence analysis. This study suggests that microarrays can be used to
reliably identify duplicated and diverged genes among cichlid species. This
information will also be critical for proper interpretation of future gene
expression profiling within and between these species.
P2.5 SCHWARTZ, Joshua/J; Pace University; [email protected]
The Effect of Anomalous Pulse Timing on Call Discrimination by
Females of the Gray Treefrog: Behavioral Correlates of Neurobiology
Recent research has demonstrated that neurons in the auditory midbrain of
anuran amphibians 'count' interpulse intervals (IPIs). The integration time of
such neurons can differ so that some neurons fire after exposure to fewer
and some to greater numbers of intervals. Moreover, the counting process
can be reset to zero if an IPI falls outside the tolerance range of the cell.
Other midbrain neurons respond with short-latencies and fire phasically
following individual IPIs of appropriate duration. Here we tested female gray
treefrogs for behavioral correlates of two neural models suggested by these
neural response patterns using phonotaxis tests. The models are also
relevant to understanding the mechanistic bases of known female responses
to calls. For example, females often prefer longer pulsed advertisement calls
to shorter calls, even when the former are presented at lower rates. Call
attractiveness can also be reduced when pulse duration and timing have
been manipulated experimentally or disrupted by acoustic interference. In
this study, female responses were consistent with neural data that
emphasize the importance of IPIs rather than pulses, per se. Females
discriminated in favor of calls with normal interpulse timing relative to those
in which a single IPI was too long or too short. Although many results were
consistent with neural models based on the characteristics of both classes of
neurons, our data indicate a somewhat stronger contribution to female
behavior by putative long-latency resettable units that count.
P1.60 SCOTT, A.J.*; GERRY, S.P.; RAMSAY, J.; WILGA, C.D.; University of
Rhode Island, Arcadia University; [email protected]
Coordination of Muscle Activity between Ventilation and Feeding in
Spiny Dogfish
Elasmobranchs (sharks, skates and rays) as well as other aquatic organisms
are believed to use similar mechanisms during ventilation and feeding.
These two behaviors rely on coordinated movements of the mandibular,
hyoid and branchial arches. Yet it is not known whether sharks suspend or
alter ventilation when capturing or processing prey. The coordination of
muscle activity during ventilation and feeding was investigated in spiny
dogfish, Squalus acanthias. Electromyograms were recorded from thirteen
mandibular, hyoid and branchial muscles thought to mediate ventilation
and/or feeding. Muscle activity was compared between resting, swimming,
prey capture and processing behaviors. While at rest and swimming, the
branchial adductor and several constrictor muscles are active in a constant
cyclic pattern as expected in a suction ventilator. These muscles are also
active during feeding, however, the duration of activation differs and was
variable among feeding events. Prey capture and processing are
characterized by additional activation of hypobranchial and jaw adductor
muscles. Previous studies have shown that feeding and ventilation places
different functional and environmental constraints on a swimming versus
feeding fish because the same structures are used for both behaviors.
However, this research shows that spiny dogfish adjust which muscles are
active as well as activation pattern of these muscles dependent on behavior.
Since jaws are thought to have evolved initially to enhance ventilation,
muscle activity during feeding can be thought of as an exaggeration of
ventilation or forced ventilation. Further investigation will show if sharks with
other ventilatory modes follow a similar pattern of coordination.
P3.115 SCULLY, T.A.*; CARROLL, K.N.; BROWN, K.M.; The George
Washinton University; [email protected]
A serotonin-mediated signaling mechanism initiates cell movements
during sea urchin gastrulation
Previous studies in our lab have identified several components of a
serotonergic system in blastula and gastrula sea urchin embryos. These
studies suggest that serotonin regulates gastrulation. In the present study we
examined the role of the serotonin synthetic enzyme, tryptophan hydroxylase
(TPH), in sea urchin embryogenesis. Embryos were treated with various
concentrations(0.5 - 20 M)of p-chlorophenylalanine methyl
ester(methyl-CPA), an inhibitor of TPH, beginning at fertilization or at the
hatched blastula stage. Cleavage was not affected, and embryo
development stopped prior to gastrulation at the mesenchyme blastula stage
with higher concentrations of the drug. Lower concentrations blocked
development at the early gastrula stage. The lowest levels of methyl-CPA to
exert effects delayed gastrulation beyond the early gastrula stage. Serotonin
(100 M) or dibutyryl cyclic AMP(1 M), added along with the inhibitor (20 M) at
hatching, rescued embryos from the inhibitory effects of methyl-CPA on early
gastrulation. Methyl-CPA also inhibited TPH activity in enzyme assays of
embryo homogenates. The nonmethylated inhibitor (CPA)did not inhibit
gastrulation. This study suggests methyl-CPA specifically blocks serotonin
synthesis and inhibits gastrulation, and serotonin regulates the primary
gastrulation phase by signaling mechanism(s)that involve cyclic AMP.
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P3.136 SEARS, Michael W.*; POLNASZEK, Timothy; ARTITA, Kimberly S.;
Southern Illinois University; [email protected]
Optimal decision rules for dispersal under activity-mortality tradeoffs
for small ectotherms in thermally-structured landscapes
Many animals perform much of their daily activity under the threat of
predation. This threat is one further stress for ectotherms that must perform
behaviors, such as foraging, while navigating complex thermal environments.
In previous models, we have examined optimal decision rules for dispersal
given the thermal preferences and physiological capacities of individuals
under different configurations of habitat in thermally-structured landscapes.
Here, we add a risk of mortality while foraging on the surface by
implementing additional decision rules that mediate activity by an individual's
state of satiation. That is, hungry individuals are more likely to forage than
satiated individuals, and mortality risk while foraging is higher than when not
foraging. We use a logistic function to describe the relationship between
satiation and foraging activity. In addition to optimizing decisions for
movement through thermally-heterogeneous habitat, we optimize the shape
of the satiation-activity function that maximize net energy intake per time
discounted by mortality. These simulations were compared under different
probabilities of mortality and foraging success (or food abundance) for
different spatial configurations of thermal habitat. Ongoing work is relaxing
implicit risks of mortality by implementing explicit predator-prey interactions
in our thermally structured landscapes. We suggest that formulations and
tests of the costs and benefits of thermoregulation should explicitly consider
risks of mortality, in addition to net energetic gains, when considering optimal
thermoregulatory strategies.
P2.118 SEPULVEDA, C.A.*; AALBERS, S.A.; DONLEY, J.M.; SYME, D.A.;
BERNAL, D.; Pfleger institute of Environmental Research (PIER), Oceanside
CA, PIER, MiraCosta College, Univ. of Calgary, Canada, Univ. of
Massachusetts, Dartmouth; [email protected]
The role of the caudal fin in the feeding ecology of the common
thresher shark (Alopias vulpinus)
The thresher sharks (Alopiidae) comprise a monophyletic group of pelagic
sharks most commonly recognized by their elongate upper lobe of the caudal
fin. It has been hypothesized that thresher sharks utilize the elongate fin to
stun small-schooling prey while feeding. The bi-functional role of the caudal
fin for both thrust production and predation represents a unique adaptation
that has not been described for any elasmobranch species. Despite the
commercial importance of the thresher sharks, there are no published
accounts on how the caudal fin is used during feeding. Field and laboratory
studies were conducted to 1) acquire video recordings of feeding common
threshers in the wild, 2) examine the caudal fin morphology and 3)
investigate the ocular morphology which enables vision in the posterior field.
Of the 140 specimens captured and released (2005-2008), only 4 sharks
were hooked in the mouth while the remainder (97%) were hooked in the
caudal fin. Video records of thresher sharks feeding in the wild yielded
footage from 20 individual caudal fin-feeding events. Morphological
examination of the common thresher caudal fin revealed that the upper lobe
is predominantly comprised of tendinous and cartilaginous support tissues.
The dissections also revealed the presence of both aerobic (red) and
anaerobic (white) muscle fibers throughout the entire length of the caudal fin.
In general, the caudal fin structural architecture appears to be similar to that
described for lamnid sharks, but with much larger dorso-ventral cartilaginous
support elements. Preliminary findings also show that the eye has the
capacity to rotate along the longitudinal axis in an anterior-posterior direction
within the orbit which may enhance vision in the posterior field.
P2.38 SERAFINI, Loredana*; TOMANEK, Lars; California Polytechnic State
University, San Luis Obispo; [email protected]
Environmental Proteomics: The Response of the Marine Model
Organism Ciona savignyi to Acute Temperature Stress
The ascidian Ciona savignyi is a basal chordate that is commonly found
along the Pacific coast of North America. Because its genome has been fully
sequenced, Ciona savignyi is an ideal model organism for proteomics
research. The response of Ciona savignyi to temperature is particularly
interesting because previous studies have shown that temperature has a
strong effect on ascidian development, especially on the metamorphosis
from the motile larval stage to the sessile adult stage. In order to assess the
effect of thermal stress on adult Ciona savignyi, we studied global changes in
protein expression in response to heat stress. To observe the effect of heat
shock, field-acclimatized animals were exposed to either a 22C or 28C
temperature treatment for 6 hours, and then allowed to recover at 13C for 16
hours, a common seawater temperature at the point of collection in central
California. Using the whole organism, with the tunic removed,
two-dimensional SDS-polyacrylamide gel electrophoresis was employed to
separate proteins and create protein expression profiles (PEPs). A one-way
ANOVA, with a critical p-value of 0.01, was performed to determine which
proteins showed a statistically significant change in expression. Of the 616
total spots, 49 spots (8%) were significantly up-regulated in the 22C
treatment, the 28C treatment, or both; and 48 spots (8%) were significantly
down-regulated in the 22C treatment, the 28C treatment, or both. Another
group of 19 spots (3%) were significantly up-regulated in the 22C treatment
group, and then down-regulated in the 28C treatment group. We are
currently using matrix-assisted laser desorption ionization (MALDI) tandem
time-of-flight mass spectrometry to identify proteins of interest and to
characterize their role in the heat shock response of Ciona.
P2.152 SERRANO-VELEZ, J. L.; TORRES-VAZQUEZ, I.; RIVERA-RIVERA,
N. L. ; FRASER, S. E.; YASAMURA, T.; DAVIDSON, K. G. V.; RASH, J. E.;
LAUDER, G. V.; ROSA-MOLINAR, E.*; Univ. of Puerto Rico-Rio Piedras,
California Institute of Technology, Colorado State Univ., Harvard Univ.;
[email protected]
Neuronal Gap Junction Coupling May Mediate a Fast Copulatory
Neuromuscular Circuit
During development, gap junctions are thought to disappear as chemical
synapses form, with one study concluding that switching from electrical to
chemical synapses requires activation of a major class of ionotropic
glutamate receptors expressed throughout the vertebrate central nervous
system (CNS), N-methyl D-aspartate receptor 1 [NMDAR1]. Using neural
tract tracing, confocal microscopy, and freeze-fracture replica immunogold
labeling in the spinal cord of an adult sexually dimorphic teleost fish
Gambusia, we show large numbers of gap junctions within dendrodentritic
mixed synapses between apical dendrites of coupled motor neurons and
interneurons. Dendrodendritic mixed synapses are a hallmark of motor
systems evolved for high-speed oscillatory neural synchronization, such as
the fast neuromuscular circuit controlling the torque-thrust movement (20 ms)
we identified in male Gambusia copulation. Gap junctions within mixed
synapses between coupled motoneurons and interneurons were heavily
labeled by antibodies to connexin 35 (Cx35), the teleost homolog of connexin
36 (Cx36) found in mammals. Postsynaptic densities [PSDs] within the mixed
synapses were glutamatergic. Work reported here demonstrates that
functional electrical and chemical synapses persist in mixed synapses in the
adult CNS, shows that collaboration between NMDA receptor activation and
gap junction coupling is possible, and suggests persistent electrical
communication may have a central role in fast neuronal circuits. Supported
by NIH grant 5 U54 NS 39405-08 (NINDS).
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P2.9 SEWALL, K. B.*; SOCKMAN, K. W.; University of North Carolina,
Chapel Hill; [email protected]
Context-dependent modulation of song effort in a territorial songbird,
the Lincoln's sparrow
Male songbirds often establish territories and attract mates by singing. Males
may assess their immediate competitors based on the relative quality of their
song. In many songbirds high quality songs are longer, more complex and
contain versions of particular song components, referred to as trills, that are
more difficult to produce. Males should be expected to modulate their song
effort to compete within the scope of their current song environment, down
and up-regulating the quality or quantity of the song they produce as a
function of their competitors songs. Modulation of song output could be
achieved through environmentally-influenced changes in singing motivation,
which may be regulated by argenine vasotosin (AVT) secretion in some
midbrain or forebrain regions. Additionally, modulation of song output could
be achieved through environmentally-influenced changes in song output,
which are associated with the volumes of vocal-control nuclei in the
forebrain. To test these predictions about the mechanisms involved in the
context-dependent modulation of song effort, we manipulated the song
environment of territorial male songbirds, Lincoln's sparrows (Melospiza
lincolnii) by exposing them to recordings of either high or low quality songs
for one week. We found that the daily song count increased over the course
of the study for males in both treatments, but the males in the high quality
song environment produced more songs overall than males in the low quality
song environment. We conclude that male Lincoln's sparrows are sensitive to
variation in the quality of songs prevalent in their surroundings and that they
modulate their own mate attraction effort as a function of their social
environment. These behavioral responses may be mediated by
environmentally-influenced changes in AVT or the volumes of some
song-control nuclei.
P2.195 SFORMO, T*; BARNES, B; DUMAN, J; SCHULTE, M; Univ. Alaska
Fairbanks, Univ. of Notre Dame; [email protected]
Modeling ice-binding motifs in antifreeze proteins from the Alaskan
beetle Cucujus clavipes puniceus
The freeze-avoiding beetle larvae Cucujus clavipes puniceus overwinters in
Alaska under the bark of decaying trees. These larvae are intermittently
exposed to ambient winter temperatures as low as -45C in situ and readily
supercool to -35 to -55C; under experimental conditions, some larvae do not
freeze even when cooled to -100C and enter a vitrified state between -58 to
-85C. We modeled C. c. puniceus antifreeze proteins (AFPs) using Sybyl
molecular modeling software (7.1 and 8.0, Tripos, Ltd.) to compare
sequence, model structure, and visualize putative ice-binding motifs. We
found that the AFPs are similar to AFPs from the beetle Tenebrio molitor.
The C. c. puniceus AFPs are 7.6 to 8.3 kDa molecules that are
threonine(Thr)- and cysteine (Cys)-rich. Each molecule is composed of six
loops of 12 amino acids, and most loops have a regular array of Thr-Cys-Thr,
with Cys internally disulfide bridged. We also show that the spacing of Thr is
approximately aligned to both ice prism and basal planes, forming the
putative ice-binding face. Stability of supercooling and vitrification in Cucujus
may be enhanced by AFPs, as well as desiccation and synthesis of
cryoprotectants. NSF #0618436
P2.129 SGUEO, CE*; WAGNER, DN; WALSH, PJ; SCHAEFFER, PJ; Miami
University; [email protected]
Seasonal acclimation of energetics in Northern Cardinals (Cardinalis
cardinalis).
Avian species are faced with varying seasonal challenges that must be met
to ensure survival, particularly non-migrant species that undergo
thermoregulatory challenges during harsh winter conditions. The summer is
also energetically expensive due to breeding and parental care. In order to
respond to environmental variation throughout a given year, physiological
changes in energy use may be occurring at both organismal and cellular
levels; therefore seasonal acclimation may be accomplished by phenotypic
plasticity of energetic capacity. We measured daily energy expenditure using
heart rate transmitters, maximum metabolic capacity, and muscle oxidative
capacity in the Northern Cardinal (Cardinalis cardinalis) in winter (December
to January) and breeding season (May to June), in order to test the
hypothesis that phenotypic plasticity of energetics is an important part of
seasonal acclimation.
P2.37 SHAFER, T.H.*; KNAPP, W.E.; GOLUS, J.M.; University of North
Carolina, Wilmington; [email protected]
A new family of crustacean cuticle proteins possibly related to
mineralization of pre-exuvial cuticle
A large group of closely related cDNAs was discovered by mining a database
of ESTs derived from the hypodermis of the blue crab, Callinectes sapidus.
Complete sequencing showed that these cDNAs code for proteins containing
the chitin-binding Rebers-Riddiford-1 motif and a conserved sequence of 14
amino acid residues just C-terminal to the RR-1. This sequence and
arrangement are not known from any other crustacean or insect cuticle
protein except C. sapidus CP14.1 (reported previously and now recognized
as a member of this new protein family) and calcification-associated soluble
matrix protein-2 from the crayfish Procambarus clarkii. Transcription of these
genes as determined by real-time qPCR is high only in pre-molt hypodermis
synthesizing exocuticle that will mineralize post-molt rather than arthrodial
membrane that remains soft. Interestingly, reverse transcriptase-PCR
revealed two sizes of mRNAs from these genes, suggesting the presence of
an unspliced intron. Sequencing the PCR products as well as genomic DNA
using the same primers confirmed this. The intron is not efficiently spliced
from some of the RNAs when transcribed post-molt, a period when the total
transcription is very low. In other cases, transcripts containing unspliced
introns were also present in hypodermis making arthrodial membrane, again
where total transcription is very low. All unspliced transcripts would translate
into truncated peptides because of in-frame stop codons in the introns.
Though the function of this new family of proteins is not known, its
expression pattern suggests a role in pre-exuvial exocuticle mineralization. A
double-strand RNA reagent has been synthesized to knock out these
transcripts, and RNAi loss-of-function assays are being attempted.
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P2.145 SHERMAN, AJ*; MURRAY, JA; TRAN, NB; HAMMOUDI, AH; Cal.
State. U. East Bay, U. Washington, U. Central Arkansas;
[email protected]
Inactivation of an identified neuron reduces oriented turning toward the
inactivated side in the sea slug Tritonia diomedea
The nudibranch mollusk Tritonia diomedea has been used extensively to
study the neural control of orientation behavior. Many of its ~7000 neurons
have been established as having specific functions and are reidentifiable
from one animal to another. One specific pair of neurons, Pedal neurons #3
(Pd3), receive modulatory input from water flow receptors, elicit contractions
of the ipsilateral foot margin, and are thus believed to be involved in
rheotactic turning behavior. Pd3 has been shown to increase in firing
frequency during turning, and stimulation of Pd3 with fine wires stimulates
ipsilateral turns. This study aims to determine if Pd3 is necessary for turning
behavior by inactivation in either or both ganglia. If Pd3 is necessary for
turning, then experimental animals will fail to turn upstream into water flow
and control animals will remain able to so after the semi-intact preparation.
Inactivation of right Pd3 (RPd3) resulted in the animal failing to crawl
upstream, but instead continually turned left. Similarly, inactivation of left Pd3
(LPd3) resulted in the animal continually turning right.. Preliminary
observations indicate that turning events involve different body positioning;
these movements are likely due to the effects of other pedal flexion neurons.
Inactivation of Pd3 may result in the use of other neurons involved in lifting
the foot margin to achieve a turning event. Kinematic analysis illustrates how
and to what extent turning behavior is modified by ablation of Pd3. These
results, together with those demonstrating that Pd3 is sufficient for turning,
further our understanding of the sensorimotor processes involved in
orientation behavior and how they are integrated to guide the animal through
its habitat.
P2.117 SILVERI, Cheryl/M*; YANOVIAK, Stephen/P; University of Arkansas,
Fayetteville, University of Arkansas, Little Rock; [email protected]
Effects of vine characteristics on foraging behavior of tropical ants
Foraging is potentially hazardous and requires energy. For central point
foragers such as ants, costs increase with increasing travel distance. Thus, it
is advantageous for ants to establish foraging trails that provide efficient
access to distant resources. Vines are a conspicuous structural component
of tropical forests and commonly serve as foraging corridors for ants. Here
we examined how two basic physical properties of vines affect foraging
patterns in tropical ants: a) vine size (diameter) vs. forager size (body length)
across a range of ant species, and b) substrate roughness and foraging
velocity in the arboreal species Crematogaster carinata. Our prediction that
large ants would be excluded from small vines was not supported; the largest
ants (Paraponera clavata and Pachycondyla spp.) essentially occurred on
the entire range of sampled vine diameters (1-180 mm). Substrate
roughness did not significantly affect foraging velocities of C. carinata at
roughness magnitudes < 1 mm (ca. 33% of the ants' body length). However,
average velocities for the fastest and slowest ants in each trial were
significantly slower on coarse substrates (particle size ca. 1 mm). Our results
suggest that ants are opportunistic with respect to the vines they use while
foraging under natural conditions. However, substrate roughness (e.g.,
different types of bark) can influence foraging speed, which may have
broader implications for interspecific interactions and access to patchy
resources.
P2.175 SIMONIK, E*; HENRY, R.P.; Ohio University, Athens, Auburn
University, AL; [email protected]
Physiological adaptations of the intertidal green crab, Carcinus maenas
to emersion
The green crab, Carcinus maenas, is intertidal during the summer months,
undergoing periods of emersion for up to 6 hr twice a day. The gills, whose
lamellae are supported by the buoyancy of water, collapse in air, causing
potential respiratory and acid-base disturbances. Elevated temperature and
reduced humidity could further contribute to metabolic stress and
desiccation. Field measurements showed that temperatures under rocks and
seaweed, where crabs take shelter, were significantly lower, and relative
humidity was higher than on the surface. Motor activity is minimal or absent
during emersion. Crabs lost about 5% of their total wet weight during 6 hr
emersion, and water loss came from the hemolymph whose osmolality
increased by about 50-100 mOsm. Crabs were able to volatilize ammonia
and thus had approximately the same rates of NH3 excretion in air and
water. As a result, changes in hemolymph NH3 concentrations were minimal.
Emersion resulted in an initial but transient bradycardia. Ventilatory rate,
measured by scaphognathite frequency, decreased by about 67% during
emersion but never ceased. Hemolymph total CO2 increased, but pH was
not significantly depressed, and aerial VO2 was similar to that in water. The
combination of low temperature, high humidity shelter and aerial
respiration/excretion reduces the environmental stress of emersion and
allows the green crab to maintain a near-undisturbed physiological state.
Supported by NSF 02-30005 and by an NSF REU site award to the Mt.
Desert Island Biological Laboratory.
P2.17 SMITH, M.*; DAVIS, M.; WOLCOTT, T.G.; SHAWL, A.L.; N.C. State
Univ., Raleigh, Harbor Branch Oceanographic Inst., Fort Pierce, FL,
N.C.State Univ., Raleigh; [email protected]
Seagrass Epiphytes and Turbulence as Settlement Cues for Conch
(Strombus alatus) Larvae
Knowledge of the mechanisms underlying larval dispersal and population
connectivity of marine organisms is needed to predict ecosystem responses
to global change, manage vital habitats, conserve threatened species, and
manage fishery stocks. Recruitment in benthic invertebrate species with
sedentary adults often depends on delivery of larvae to suitable habitats.
Most larvae are not just passive particles, and the interactions of larval
behavior and the local current regime play an important role in dispersal and
settlement. Conch larvae respond to contact with benthic trophic cues by
metamorphosing. We hypothesized that while planktonic, they also respond
to water-borne cues and increased turbulence (symptomatic of shallower
water) as indicators of potential nursery habitats. By swimming down or
sinking, they increase their chances to explore the substrate and come in
contact with metamorphic cues. Laboratory reared larvae competent to
metamorphose responded to water-borne cues from epiphyte communities
common on Thalassia testudinum blades by swimming faster, which would
increase the frequency of contacts with the bottom. They also
metamorphosed sooner than controls. Both phenomena would increase the
probability of settling in suitable nursery habitats. When exposed to
turbulence typical of shallow tidal flows, competent larvae, generally already
low in the water column, showed no response. Pre-competent larvae, on the
other hand, withdrew their velar lobes and sank. This would favor transport
along or near the bottom and increase the probability of encountering
suitable nursery habitats and settling there when competent.
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P3.186 SMITH, A.R.*; CARLETON, K.L.; University of Maryland;
[email protected]
Intrageneric Sequence Diversity in Cichlid Opsin Arrays
Peptide sequence diversity is not expected to be a source of significant
variation in the visual arrays of Malawian cichlids due to the young age of the
species flock. However, we know very little about the actual degree of opsin
sequence diversity within the lake. Perhaps more importantly, we know even
less about intrageneric polymorphisms. Amino acid changes in opsin
structure can fine-tune visual spectral sensitivities, thereby contributing to
divergence in visual arrays. In this study, we sequenced seven opsin genes
in eight species from each of two divergent genera, Labidichromis and
Metriaclima. The raw gene sequences were aligned to published reference
sequences derived from Metriaclima zebra. The introns were excised and the
genes were translated to their corresponding proteins. In addition, the amino
acid sequence was threaded onto the bovine rhodopsin structure to
determine the spatial relationships between polymorphic sites. Sequence
divergence was found to be common, even within a genus. For example, the
SWS1 and RH2Aβ in the genus Metriaclima had 14 and 17 polymorphic sites
respectively. These numbers are on par with the number of sites that differ
between M. zebra and the riverine tilapia O. niloticus. Several of the
polymorphic sites are in close proximity to the retinal binding pocket,
indicating that they may be functional variants with different spectral
sensitivities. These data suggest two potential, but not mutually exclusive,
possibilities: (i) balancing selection maintains polymorphisms in populations
and (ii) ancient alleles have entered the lake repeatedly. Either scenario has
profound implications for sensory evolution and sexual selection on visual
signals.
P1.9 SMITH, Jeffrey J.*; SEARS, Michael W.; Southern Illinois University;
[email protected]
The implications of body size for habitat selection as a consequence of
behavioral thermoregulation
Body size is an important factor determining the range of body temperatures
available to an ectotherm on a daily basis. Typically, small- and
medium-sized vertebrate ectotherms (< 1 kg) can potentially experience
body temperatures that range over a span of 30 C. To optimize physiological
performance, individuals can use behavioral thermoregulation to minimize
this variance by differentially selecting microhabitats in an environment. The
ecological implications of this behavior is that animals that differ in size will
likely occupy different parts of the environment to maintain similar body
temperatures all else being equal, and that time for activity will differ for
individuals of different sizes across microhabitats. Here, we use a simulation
to explore the implications of thermoregulation for daily and seasonal activity
for differently sized reptiles in a spatially-explicit, thermally-heterogeneous
landscape. Several patterns emerge from these simulations. With respect to
time, relatively small individuals can take advantage of microhabitats for
heating at earlier times of day than larger individuals. Further, the activity of
relatively small individuals is depressed during the hottest times of day and
year. With respect to space, smaller individuals cannot penetrate as deeply
into cooler (shaded) habitat as can larger individuals. Implications are that
these shifts in spatiotemporal patterns of activity might be able to relieve
intraspecific or interspecific competition among individuals that coexist in
space.
P3.102 SMITH, L.C.*; MENDONCA, M.T.; RICHARDSON, C.S.; WIDMAIER,
E.P.; HOHMANN, M.G.; Auburn University, AL, Boston University, MA,
Boston University, MA, US Army ERDC-CERL; [email protected]
Neutrophil/Lymphocyte Ratio and Stress in Three Species of Myotis:
Effects of Sex, Reproductive Stage, Size-Corrected Mass and Site.
We examined variation in neutrophil/lymphocyte ratio (N/L) and fecal
glucocorticoid (FG) levels in three species of bats from the eastern U.S.
Myotis septentrionalis (MSE), M. lucifugus (MLU), and M. sodalis (MSO), in
order to assess whether anthropogenic disturbance (i.e. urbanization, military
activity) may constitute a chronic stressor and potentially affect the exposed
animals immunocompetence. Bats were captured by mist net at impacted
and non-impacted sites in Indiana and Kentucky from May to August, 2007.
Blood was taken within three minutes of capture, and analyzed to determine
N/L. FG levels were obtained from fecal pellets collected up to 1.5 hrs
post-capture. Size-corrected mass (SCM) was calculated as the residuals of
body mass against forearm length. We compared N/L among species, sexes,
sample months for males, reproductive status for females, and sites. We also
examined FG levels and SCM in relation to N/L for these same groups.
Males showed no significant differences. However, MSE females showed
variation in N/L by reproductive stage (p=0.004): ratios for pregnant and
lactating females were significantly higher than those of post-lactating
females. A similar trend was present in MLU and MSO females, but not
significant. Also, MSO females N/L were significantly higher than those of
MLU and MSE (p=0.004). Additionally, N/L of pregnant and lactating MSE
females from impacted areas were significantly higher than those from
non-impacted sites (p=0.02), suggesting that these bats may have been
under chronic stress, which might have an effect on their immune response.
Preliminary analysis indicates little to no relationship between N/L, FG levels,
and SCM.
P2.41 SOLEM, R. Christian*; EAMES, Brian F; TOKITA, M; SCHNEIDER,
Richard A; Harvard University, University of Oregon, Kyoto Univeristy,
University of California, San Francisco; [email protected]
Mechanical and Mesenchymal Mechanisms of Secondary
Chondrogenesis
Secondary cartilages, which arise after formation of the primary cartilaginous
skeleton and during later stages of osteogenesis, are found within joints,
ligaments, and tendons. Secondary cartilages facilitate skeletal movement
and much evidence suggests their induction requires mechanical stimulation.
Thus, the evolutionary presence or absence of such cartilage reflects
species-specific variations in functional anatomy. To investigate molecular,
cellular, and biomechanical mechanisms that regulate secondary cartilage
formation, we conduct experiments using quail and duck, which exhibit
distinct jaw morphologies and modes of feeding. Duck use levered straining
and have a prominent secondary cartilage at the insertion of the jaw
adductor muscle. An equivalent cartilage is absent in quail, which peck at
their food. We hypothesize that differences in jaw morphology and the local
mechanical environment promote secondary chondrogenesis in duck versus
quail. As a test of our hypothesis, we employ two experimental approaches.
First, we alter the mechanical environment in embryonic duck by paralyzing
skeletal muscles and by blocking mechanotransduction through stretch
activated channels. Second, we re-pattern the duck jaw complex to resemble
that found in quail by transplanting neural crest mesenchyme destined to
form skeletal and connective tissues of the jaw. This mesenchyme is known
to generate species-specific pattern. Both approaches inhibit secondary
cartilage formation by altering expression of genes required for cartilage,
bone, muscle, and tendon development. We conclude that
mesenchyme-dependent changes in gene expression, musculoskeletal
pattern, and mechanical forces control secondary cartilage induction.
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P2.53 SOU, E.*; HERNANDEZ, L. P.; George Washington University,
Washington DC 20052; [email protected]
Investigating the mechanisms responsible for the evolutionary origin of
a greatly hypertrophied cypriniform ceratobranchial 5
Significant hypertrophy of the pharyngeal jaws and concomitant loss of oral
jaw teeth characterize most cypriniform fishes. While cichlid pharyngeal jaws
have received much attention from evolutionary morphologists,
understanding the evolution of the hypertrophied ceratobranchials that
comprise the cyprinid pharyngeal jaws has received little attention. Here we
use both a phylogenetic approach as well as an ontogenetic analysis of
growth to examine the origin and evolution of the hypertrophied
ceratobranchials. A phylogenetic survey of basal teleosts and
Ostariophysans to determine the relative size of ceratobranchials early in
teleostean evolution has never been undertaken. Our findings suggest that it
is only at the base of Cypriniformes that we see a greatly hypertrophied
ceratobranchial 5. Indeed in several more basal clades, including
Gonorhynchiforms (sister to Cypriniformes) and Clupeomorpha, the fifth
ceratobranchial is markedly smaller than more anterior ceratobranchials.
Interestingly other otophysan groups are also characterized by a smaller
ceratobranchial 5. Using the zebrafish as a model cypriniform we also
examined growth of all ceratobranchials from their first origin as cartilaginous
elements at early larval stages until adulthood when all elements have
undergone ossification, in order to better understand the developmental
mechanisms via which such changes in ultimate size may have occurred.
Growth rate of all ceratobranchials changed significantly during larval
development, with a marked increase in growth rate corresponding to the
onset of mineralization. Both the timing of initial differentiation as
cartilaginous elements, as well as increased growth rate, appear to be
involved in the generation of the hypertrophied jaws.
P3.110 SRINIVASAN, DG*; ANO, L; DAVIS, GK; STERN, DL; Princeton
University, Macalester College, Bryn Mawr College; [email protected]
Molecular Basis of Facultative Asexuality in Aphids
Phenotypic plasticity allows organisms to quickly adapt in response to
changing environments. Little is known of the genetic, environmental and
epigenetic contribution to the expression of alternative adaptive
developmental outcomes. We study aphid polyphenisms, which offer a
unique, compelling opportunity to study multiple levels of biological
organization, especially insect epigenetics. The pea aphid, Acyrthosiphon
pisum, exhibits an adaptive reproductive polyphenism whereby genetically
identical individuals reproduce either sexually (meiosis) or asexually
(parthenogenesis) depending on environmental conditions during maternal
development (short or long photoperiod, respectively). To understand how
facultative asexuality evolved in aphids, we first determined meiosis gene
activity in sexuals and asexuals. I determined that the pea aphid genome
encodes single copies of homologs for the majority of the core meiotic
machinery, suggesting that meiotic plasticity is not due simply to gene loss or
expansion. Next, we determined if these core meiosis genes are expressed
using PCR spanning across at least one intron from cDNA isolated from
asexual and sexual ovaries. Surprisingly, meiosis specific genes (e.g.,
Spo11, Msh4, Msh5, Hop2 and Mnd1) are expressed in not only in asexual
ovaries but also in somatic tissue and an obligately asexual aphid strain.
Interestingly, the Spo11 PCR product contained intronic sequence, thus
representing unspliced mRNA. Germline expression of Spo11, Mnd1 and
Hop2 was confirmed by in situ analysis. Preliminary results identified
candidate methylation sites in the Spo11 locus, indicating an epigenetic
basis for this expression difference. Further characterization will help us
better understand the molecular and epigenetic mechanisms underlying this
adaptive facultative plasticity.
P1.86 ST. LOUIS, J*; SANGER, TJ; HSIEH, T; Harvard Univeristy, Harvard
University, University of Florida; [email protected]
How the development and microstructure of toe pad morphology reflect
habitat specialization in Anolis lizards
Squamate lizards have repeatedly evolved specialized adhesive toe pads
(lamellae) which provide superior clinging ability to the groups that posses
them. The extraordinary adhesive properties of these toe pads are due to
microscopic setae found covering each lamellar scale. While variation is
known to exist in toe pad morphology among different groups of lizards, it is
unclear whether this variation has functional consequences to lizards living in
different habitats. It is also unknown when in development toe pad structures
arise, raising additional questions regarding the performance capabilities of
juvenile lizards. Anolis lizards provide the rare opportunity to examine both of
these questions on a diverse radiation of lizards inhabiting different arboreal
microhabitats. Anolis habitat specialists occupying different islands but
similar environments exhibit remarkable morphological similarity. For
example, species that live higher in the canopy typically have larger toe pads
comprised of more lamellae compared to species living low in the canopy or
on the ground. In this study we have compared the microstructure of
approximately 20 Anolis species occupying different microhabitats using
scanning electron microscopy. Toe pads were dissected into thirds using a
fine scalpel to quantify setal morphology and density. A preliminary analysis
of approximately 200 micrographs indicates that several species living high
in the canopy have more complex setal architecture than their
ground-dwelling relatives. We have also established breeding colonies for
two species, A. sagrei and A. carolinensis, to examine toe pad embryology.
We found that variation in lamellae number arises at the earliest stages of
toe pad development, potentially during toe pad patterning, but that setal
variation does not appear to arise until at or slightly after hatching.
P1.56 STAAB, KL*; FERRY-GRAHAM, LA; HERNANDEZ, LP; George
Washington University, Moss Landing Marine Labs;
[email protected]
Morphological and Kinematic Variation in Upper Jaw Protrusion of Four
Species of Cyprinid Fishes
Cyprinidae is the largest family of freshwater fishes and likely owes some of
its success to the novel feeding mechanism employed by members of the
group. Cyprinid fishes effect premaxillary protrusion via a kinethmoid, a novel
sesamoid ossification within the rostral skeleton that is a cypriniform
synapomorphy. The kinethmoid is entirely suspended by ligaments to the
premaxillae, maxillae, palatines, and neurocranium. While the ligamentous
attachments are relatively conserved among species, there is variation in
kinethmoid shape. Cyprinid fishes are trophically diverse with most species
feeding on secondary producers such as macrocrustaceans and insects.
Many basal members are benthic feeders, while others can switch between
pelagic and benthic modes depending on food availability. Our previous work
has suggested that morphological variation of the kinethmoid is more likely to
be correlated with ecological niche than phylogenetic position of a species
within the group. Here we performed kinematic analyses on four cyprinid
species with widely varying kinethmoid shape. Our initial hypothesis was that
Carassius auratus, a species with an elongate kinethmoid that feeds on
benthos would have slower protrusion speeds than species that feed on
insects and possess shorter kinethmoids. We found the opposite to be true.
C. auratus protrudes its upper jaw faster than Gila robusta, Danio rerio, and
Devario aequipinnatus. C. auratus is a member of the Cyprininae, the most
basal subfamily within Cyprinidae. Our data suggest that when
kinethmoid-mediated premaxillary protrusion first evolved, it was a versatile
mechanism, allowing basal cyprinids to search through benthos as well as
effectively capture elusive prey.
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P3.127 STAHLSCHMIDT, ZR*; DENARDO, DF; Arizona State Univ. Tempe; [email protected]
Effect of nest temperature on egg-brooding behavior, metabolism, and
clutch-nest thermal relations in Children's pythons (Antaresia childreni)
Parental care meets several critical needs of developing offspring, and
egg-brooding in pythons is an exceptional model for examining
environmental influences on specific parental behaviors because python
egg-brooding is limited in complexity, dynamic yet limited in spatial
movement, and modulates embryonic temperature, respiration, and water
balance. We used captive Childrens pythons (Antaresia childreni) to assess
their facultative endothermic capability, the influence of the gradient between
the nest temperature (Tnest) and clutch temperature (Tclutch) on
egg-brooding behaviors, and the effect of these behaviors on the
developmental micro-environment. We monitored maternal egg-brooding
behavior, rates of brooding unit (i.e., female and associated clutch)
respiratory gas exchange, Tnest, Tclutch, and intra-clutch oxygen tension
(PO2clutch) during acute changes among four incubation temperature
conditions: constant preferred temperature (31.5C); cooling (Tnest <
Tclutch); constant cool temperature (25.6C); and warming (Tnest > Tclutch).
We demonstrated that A. childreni are not facultatively endothermic because
brooding unit Q10 for and were similar to other ectothermic boid snakes (1.9
- 5.7) and Tclutch conformed to Tnest at the constant, cool temperature
treatment. Females coiled tightly around eggs more often during cooling to
conserve clutch heat and less often during warming to expedite an increase
in Tclutch. Additionally, the amount of time that females spent tightly coiled
during warming significantly affected the Tnest-Tclutch gradient. Together
these results indicate that, although female A. childreni are not facultatively
endothermic, they are capable of assessing the Tnest-Tclutch gradient and
making behavioral adjustments to enhance the thermal micro-environment of
their developing offspring.
P2.116 STEPHENS, Tiffany/A*; BRITTON-SIMMONS, Kevin; University of
Washington and Friday Harbor Laboratories, Friday Harbor Laboratories;
[email protected]
Feeding preference of Strongylocentrotus franciscanus for aged versus
fresh kelp
Detrital macroalgae, particularly kelp, is an important food resource for sea
urchins and other animals in many regions worldwide. However, most of
what is known about consumer preferences for kelp comes from feeding
trials conducted using fresh tissue. Detrital kelp undergoes important
biochemical changes as it ages that potentially change its palatability and
nutritional content relative to fresh tissue. We investigated the feeding
preference of the red sea urchin Strongylocentrotus franciscanus for fresh
versus aged (7 and 14 days) blade tissue from the kelps Nereocystis
luetkeana, Agarum fimbriatum, and Saccharina subsimplex. Urchins were
offered fresh versus aged pieces of blade tissue from each kelp species and
a choice was recorded when urchins began feeding on one of the two pieces
offered to them. We found that for Nereocystis luetkeana and Saccharina
subsimplex urchins preferred aged over fresh tissue and the strength of this
preference increased with tissue age. In contrast, fresh Agarum fimbriatum
was always preferred over aged tissue. These results indicate that aging can
influence food preference and that the effect of aging varies among kelp
species. In systems where consumers have access to both fresh and detrital
kelp tissue it may be important to evaluate how aging of detrital material
influences consumer preferences in order to understand patterns of resource
use in the field.
P1.45 STEWART, W.J.*; MCHENRY, M.J.; Univ. of California, Irvine;
[email protected]
The unsteady flow sensed by larval zebrafish
The ability to detect the water flow generated by a predator can be essential
to the survival of a larval fish. However, it is not well understood what flow
stimuli a larval fish detects before triggering an escape response. Therefore,
we experimentally investigated the hydrodynamics of a larval zebrafish's
(Danio rerio) body during capture in tethered larvae within a flow tank
specialized for creating the impulsive flow generated by a feeding predator.
We measured the boundary layers generated by this flow with particle
tracking velocimetry (PTV). Preliminary data show that the boundary layer
along the fish body extends to about twice the height of flow-sensitive lateral
line receptors. This suggests that the boundary layer attenuates the flow
stimulus created by a fish predator and thereby hinders their ability to evade
capture.
P1.165 STICKLES, E.M.*; SAKHTAH, H.; DOORLY, N; LIEW, C.-W.; ROOT,
R.G.; LONG, J.H.; Vassar College, Case Western University, Lafayette
College; [email protected]
Modeling Swimming Behavior with Perception-Action Feedback Loops
in Autonomous Biorobotic Fish
In order to model the swimming behavior of fish, we use a method borrowed
from behavior-based robotics in which sensorimotor (input-output) systems
are represented as perception-action feedback loops (PAFLs). PAFLs are
modular feedback systems that causally connect sensory information, neural
systems, motor output, and environmental interaction. PAFLs can be
designed into an agent-environment system in a variety of patterns: solo, in
parallel, in series, or in a nested hierarchy. Using a two-layer nested PAFL
design, we have built an autonomous fish-like prey robot that forages for light
and avoids, when detected, a stalking predator. This robotic simulation is
meant to mimic the neural system of fish when Mauthner and related
reticulospinal cells override the central pattern generators, used in cruising,
in order to create a rapid escape maneuver. Sensory systems model eyes
(photoresistors in the low-level PAFL) and a lateral line (IR proximity
detectors in the high-level PAFL). Motor output models an undulating tail,
capable of turning, with a vertebral column actuated by a single anterior
servo motor. With this system, we are able to analyze the connections
between sensory input, neural processing, body structure, mechanical
properties, and behavior in the context of a predator-prey ecology. This work
was supported by NSF DBI-0442269.
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P1.61 STOEHR, A.S.*; WILGA, C.D.; University of Rhode Island;
[email protected]
Prey Processing in Elasmobranchs
Prey processing is an integral part of the feeding process, however, there are
relatively few studies that focus on post-capture behavior in fishes. The hyoid
arch has been shown to play a key role in the feeding mechanism of fishes.
The position of the hyomandibulae is related to prey capture mode in
elasmobranchs. How the position of the hyomandibula relates to jaw
mechanics and the generation of pressure in the buccal, hyoid, and
pharyngeal cavities is little understood for prey processing. This study
compared the effects of jaw, hyoid and branchial arch morphology on prey
processing in white-spotted bamboo sharks (Chiloscyllium plagiosum), spiny
dogfish (Squalus acanthias), and little skates (Leucoraja erinacea), which
possess lateral, slightly posterior, and anterior hyomandibular orientations
respectably. The kinematics of the jaws, hyoid, and 3rd branchial arches and
associated pressures were quantified during suction and bite processing. As
expected, mouth opening and arch expansion primarily creates subambient
pressures, while mouth closing and arch compression generates
superambient pressures to move the prey within the oropharyngeal cavity.
Bite events are longer in duration than suction events. Skates had the
longest durations and bamboo sharks generated greater peak pressures for
all events. The hyoid and pharyngeal arches move in synchrony during
suction and bite processing in skates and dogfish, but not in bamboo sharks.
The disparate cavity motions during prey processing reflects different
degrees of cranial kinesis and morphological constraint among the
elasmobranchs.
P3.60 STOVER, K.K.*; BIKNEVICIUS, A.R.; Ohio U. Honors Tutorial
College, Ohio U. College of Osteopathic Medicine; [email protected]
Limb function during gait initiation in dogs
The triggers for gait changes, such as the progression from a walk to a run,
have been explored extensively in humans and some quadrupeds. Published
reports focus on the mechanics of the center of mass (COM) without
exploring how individual limbs contribute to gait transition. The purpose of
this study is to distinguish the roles of the forelimbs and hind limbs in the
ultimate gait transition, namely, gait initiation (from standstill to walk).
Understanding the simplest form of gait transitions may lead to greater
insight into the more complex transitions that occur at higher speeds. Seven
Labrador Retrievers (22.2-51.3 kg) were recruited to take part in the study. A
Kistler force platform was used to capture the vertical, craniocaudal and
mediolateral ground reaction forces of individual limbs during gait initiation.
We analyzed peak vertical force, vertical impulse and propulsive impulse in
trials with squared initial postures. The gait initiator (first limb to move) was a
hind limb in 75% of the trials; subsequent limb liftoffs followed a lateral
sequence pattern (e.g., right hind, right fore, left hind, left fore). The gait
initiator hind limb was unloaded with almost no propulsive effort, and the
ipsilateral forelimb showed a similar pattern. This effectively shifted the body
weight contralaterally away from the gait initiator side, increasing the vertical
support roles of the contralateral limbs. The contralateral limbs, with both the
hind limbs and forelimbs acting equally, generate nearly all of the initial
propulsive effort for gait initiation.
P1.50 STOVER, K.K.; WILLIAMS, S.H.*; Ohio University; [email protected]
Ontogeny and fusion of the mandibular symphysis in camelids
Ontogenetic ossification, or fusion, of the mandibular symphysis in mammals
is thought to be associated with weaning and the shift to an adult diet. In
particular, symphyseal fusion may be biomechanically advantageous for
strengthening and/or stiffening the symphysis against routine masticatory
loading. Recent work on alpacas (Lama pacos), which exhibit ontogenetic
symphyseal fusion, demonstrate significant differences in jaw-muscle
recruitment patterns and symphyseal loading between pre-weaned and adult
alpacas. However, the morphological context for these differences, and in
particular the ontogeny of symphyseal fusion, is not fully understood. Here,
we describe the morphology of the pre-fused symphyseal joint and
characterize the pattern of ossification of the mandibular symphysis in
camelids using osteological and fresh specimens and CT scans of live
animals. Symphyseal development is then related to various masticatory
parameters, including EMG and bone strain data from alpacas. The
pre-fused symphysis of neonate and infant camelids consists of two relatively
flat symphyseal surfaces. Ossification of the joint begins rostrally, with some
individuals fusing first along the lingual portion and others along the labial
portion. In some individuals, minor bony interdigitations develop in the caudal
and labial region of the symphyseal joint prior to full fusion. Fusion is
complete between 6 and 8 months. Thus, full fusion precedes or is
coincident with occlusion of the first molar yet significantly precedes the
onset of adult chewing motor patterns and symphyseal bone strain patterns.
Although the pattern of fusion cannot be directly related to observed strain
patterns, we cannot rule out that forces generated during mastication in
pre-weaned individuals influence ossification of the symphyseal joint.
P1.68 STRACHAN, L.A.*; TARNOWSKI, H.E.; SINCLAIR, B.J.; University of
Western Ontario, London, ON; [email protected]
The evolution of insect cold tolerance: A Drosophila model
Insects survive subzero environments using cold tolerance strategies
generally divided into two categories: freeze tolerant and freeze avoiding. In
spite of extensive research on insect cold tolerance, the evolutionary
influences on the choice of strategy remain unclear. Most freeze tolerant
dipteran species survive freezing as larvae; however, previous Drosophila
studies have focused primarily on the adult fly. We hypothesise that both
freeze avoiding and freeze tolerant strategies will be present in Drosophila
larvae, and use a comparative approach to examine cold tolerance attributes
among species. Low temperature survival, supercooling points (SCPs) and
cold tolerance strategies were determined in larvae of 27 Drosophila species.
In addition, the relationship between body size, water content and SCP was
studied, and acclimation regimes and inoculative freezing were used to
mimic natural environmental conditions. A Drosophila phylogeny was
developed using the COI, COII, and 28s sequences of all species in stock.
We then examined the factors influencing cold tolerance in a
phylogenetically-independent context in an effort to map how strategies have
evolved within the genus. Thus far no freeze tolerant larvae have been
observed. Among species, lower lethal temperatures span a range of ten
degrees; and freeze avoiding species are distinct from chill susceptible
species. Additionally, we found body mass and absolute water content are
stronger determinants of SCP than phylogeny, and species differ in
hardening capacity during acclimation regimes.
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P1.105 STREETS, Amy*; SOARES, Daphne; univeristy of maryland;
[email protected]
Hunting strategies of the mexican tetra fish Astyanax mexicanus larva
The emergence of new species-specific behaviors is only possible due to the
evolutionary malleability of neural circuits. In the tetra fish Astyanax
mexicanus, we find a particularly good window into the adaptation of
behavior during speciation. Currently, Astyanax is undergoing allopatric
speciation and is extant in two forms: an ancestral, sighted river dwelling
form and a derived, blind cave dwelling form. Although adult cavefish lack
functional eyes, small eye primordia form during embryogenesis, but later
arrest in development, degenerate, and sink into the orbit. Because the
degeneration of the retina in the cavefish takes a few weeks posthatch, we
hypothesized that these animals have a functional visual system as larvae.
We used a visually guided prey catching assay to examine the level of
performance of cavefish versus riverfish from 1 week to 1 month of age. We
expected that if cavefish use their visual system alone to catch prey, then
their performance would initially be comparable to river dwelling fish but then
decrease as their retinas degenerate. Alternatively, despite having eyes
larvae could use different hunting strategies from the beginning, such paying
more attention to lateral line information. We tested animals in light and dark
environments and after disruption of lateral lines by exposure to an
aminoglycoside antibiotic (gentomicin), which kills hair cells. It appears that
cavefish already use different exploratory and prey catching behaviors from
the larval stage.
P1.22 STRILEY, D.S.*; BUDEN, A.T.; ARONOWSKY, A.; WESTNEAT,
M.W.; Biodiversity Synthesis Center, Field Museum;
[email protected]
Using the Encyclopedia of Life for New scientific discoveries: the
Biodiversity Synthesis Center
The Encyclopedia of Life (EOL) has a simple but ambitious vision: to develop
a webpage for every species on earth that is freely accessible to all and
contains up to date, vetted scientific information. Recently launched, the EOL
is moving quickly towards it goal, currently featuring almost 100,000 species
pages containing multimedia visualizations of species and their ecosystems,
descriptive text, and links to a vast library of scanned scientific literature. This
unprecedented resource will serve as a primary research and educational
tool for a worldwide audience that includes scientists, government agencies,
conservationists, teachers, and students. To extend the EOLs impact and to
begin using it to answer vital scientific questions, the Biodiversity Synthesis
Center (BioSynC) functions as the EOL think tank. As such, it is a place
where researchers and academics from around the world gather in focused
Synthesis Meetings to ask and answer new scientifically revolutionary
questions about the biology of life. Synthesis meetings cover a range of
topics, including; megadiverse groups, novel research questions in
biogeography, evolution, systematics and taxonomy, visualization of large
data sets, and the study of biodiversity hotspots. We will present summaries
of recent synthesis meetings which have developed content and informatics
tools for the EOL. We will also demonstrate some of the new tools to allow
systematists to organize and archive their content on the EOL.
P3.170 SVANCARA, Kevin; BOORSE, Graham *; Arizona State University,
West Campus; [email protected]
Evolution of the vertebrate CRF system: molecular cloning and
characterization of CRF-like peptides, receptors and binding protein in
the lizard, Anolis carolinensis
Corticotropin-releasing factor (CRF)-like peptides modulate an organism's
endocrine, autonomic, and behavioral responses to stress by binding and
activating either of two G protein-coupled receptors (CRF1 and CRF2). At
least four paralogous lineages of CRF-like peptides exist in vertebrates.
Previous studies have characterized the CRF stress system across different
vertebrate taxa (e.g. fish, amphibians, bird and mammals). However, no
studies have characterized the CRF system of squamates (e.g. lizards and
snakes). The stress system likely serves important roles in underlying
common lizard behaviors such as dominance and territoriality. By analyzing
the A. carolinensis genome, we have identified genes involved in the CRF
system. Using molecular cloning techniques, we have successfully isolated
cDNAs for lizard CRF, urocortin 3 (UCN3), CRF1, CRF2 and CRF-binding
protein (CRFBP). The deduced amino acid sequence of each molecule
shares considerable sequence similarity with its human ortholog: CRF
mature peptide (100%), UCN3 mature peptide (90%), CRF 1 (75%), CRF2
(70%), and CRFBP (77%). An additional cDNA encoding a mature peptide
that shares 61% identity with human CRF and 40% with human urocortin 1
(UCN1) was also identified. Using molecular phylogenetic analyses in
conjunction with synteny mapping we have tentatively identified this molecule
as lizard UCN1 rather than CRF. Tissue distribution of these genes via
RT-PCR and binding affinity studies are currently underway.
P1.167 SWIDERSKI, D.L.*; BASU, I.; ZELDITCH, M.L.; Univ. of Michigan;
[email protected]
Modularity and Integration of the Stapes: analysis of variation in the
guinea pig
Like other model systems analyzed in studies of modularity and integration,
the stapes has a complex developmental history: three ossification centers
form in the cartilage of the second branchial arch, which fuses to the wall of
the otic capsule, and is also excavated by the stapedial artery. Unlike those
other models, the stapes has but one simple function: the transmission of
sound as it is driven forcefully into the fluid-filled inner ear. Thus, the goal of
our study was to determine whether variation in stapedial shape reflects the
modularity of development or the integration of function. We collected stapes
from adult guinea pigs that had been the subjects of unrelated surgical
experiments, and quantified shape geometrically, using landmarks at
discrete anatomical loci and semilandmarks outlining the crura and footplate
(the legs of the arch and the elliptical saucer it stands in). Preliminary results
indicate that the outer edges of the crura are more variable than the inner
margins of the arterial foramen, and that the feet of the crura are more
variable than the head of the stapes. The long axis of the footplate appears
to be proportional to height of the arch, but its width and depth are
independent. These results suggest that stapes shape is not highly
integrated despite the apparent simplicity of its functional role.
e312
P3.190 SWOFFORD, Ross W.*; LOH, Y.H. Eddie; STREELMAN, J. Todd; DI
PALMA, Federica; LINDBLAD-TOH, Kerstin; TILAPIA SEQUENCING
CONSORTIUM, ; Broad Institute of MIT and Harvard, Georgia Institute of
Technology, Tilapia Sequencing Consortium; [email protected]
Deep segregation of single nucleotide polymorphisms (SNPs) in East
African cichlids
The Broad Institute will sequence the complete genome of the Nile Tilapia
and the genomes of two additional cichlids from East Africa. The African
cichlids represent classic examples of adaptive radiations, and evolutionary
divergence due to natural and sexual selection. Remarkably, the cichlids of
Lake Tanganyika have diverged into ~250 species in the past 6-8 million
years, and the ~500 Lake Victoria species and the ~700 Lake Malawi
species diverged in only the past 1 million years. The cichlids are especially
diverse in tissues and systems related to the neural crest (jaws,teeth,
pigment), and are valuable model organisms for the study of sex
determination, behavior, and speciation. The combination of a sequenced
cichlid genome and the wide variety of recently evolved cichlid behaviors and
morphological traits will provide a unique opportunity for the study of
evolution and the genetic basis of a variety of developmental and ecological
traits. The Broad Institute, in collaboration with the research community,
carried out a preliminary study to further understand genetic diversity within
and among the East African cichlid species flocks. DNA samples from 192
cichlid individuals representing populations from Malawi, Tanganyika,
Victoria and associated drainages were genotyped at 132 SNP loci,
previously identified from comparison of 5 Malawi individuals. Notably, we
observe that a large fraction of SNPs segregate beyond Malawi taxa, deep
into the lineages of Lakes Tanganyika and the East African haplochromines.
We present proof of concept that these markers are ideal for comparative
genomics and the study of cichlid population genetic structure.
P3.69 SZARKO, M.J.*; BERTRAM, J.E.A.; University of Calgary;
[email protected]
Some Tissues Like It Fast: Dynamic, Low Magnitude, High Frequency
Analysis of Viscoelastic Tissues
As limbs strike the ground during terrestrial movement ground reaction
forces composed of relatively high frequency transient stress waves (over
100 Hz during human heel strike) travel up the skeleton. Many natural
shock-absorbing structures within the musculoskeletal system have
viscoelastic, time-dependent behaviours that may be sensitive to this high
frequency loading, especially if compromised by over-use, over-loading or
disease. Identification of loading-rate dependent behaviour, non-destructive
low amplitude (0.01 MPa) dynamic compression tests were used. Loading
involved 0.1-100 Hz equal amplitude sinusoidal waveforms periodic in the
time record. Storage and loss moduli derived from load-deformation results
allowed the calculation of both complex stiffness and hysteretic energy loss.
As a model, articular cartilage was used to characterize loading-rate
dependent behaviours of viscoelastic tissues. Investigating an osteoarthritic
disease model of articular cartilage revealed that an intact collagen network
is critical for normal hysteresis, above 30 Hz. Identifying mechanical
freeze-thaw effects on articular cartilage found lower frequency (<20Hz)
hysteretic differences for tissues stored at -20 oC and high frequency
differences for tissues snap frozen in liquid nitrogen and stored at -80 oC.
Sodium movement in articular cartilage, hypothesized as a cause for the
altered biomechanics caused by freeze-thaw was assessed by exposure to a
range of sodium concentrations. Stiffness decreased at lower frequencies
(<20Hz) at 1M NaCl, but increased at higher frequencies (40-59 Hz) at 5M
NaCl. The loading-rate sensitivity found in articular cartilage may be
applicable to other viscoelastic musculoskeletal tissues and reveals low
magnitude, high frequency dynamic testing as a new avenue for discovering
novel tissue responses to the physiological range of loading rates.
P3.85 SZUMOWSKI, Suzy C.*; BOYER, Sarah L.; HORNBACH, Daniel J.;
HOVE, Mark C.; Macalester College; [email protected]
A comparison of genetic variation between populations of pocketbook
and pimpleback mussels above and below the St. Croix Falls dam
(Minnesota/Wisconsin, USA)
There are forty-eight species of mussels native to Minnesota, and more than
half of them are listed as endangered, threatened, or of special concern. The
St. Croix River is a superior habitat for mussels, likely due to relatively light
human disturbance in the watershed, although since 1903 there has been a
hydroelectric dam at St. Croix Falls. Because the life cycle of mussels
involves a larval growth phase in which the mussels are dependent on fish
hosts for transportation, this barrier could greatly affect mussel population
structure. Both Lampsilis cardium and Quadrula pustulosa are known to have
multiple fish hosts, primarily catfishes for Q. pustulosa and sunfishes and
perches for L. cardium. It has been observed in previous studies that the
mussel assemblages above and below the St. Croix Falls differ, and that this
variability is not likely to be a result of variation in microhabitat factors, such
as substrate composition and water velocity. To determine the extent to
which mussel populations above and below the dam are isolated from one
another, small tissue samples from the mantles of 20 L. cardium and 20 Q.
pustulosa were collected at four locations; two above the dam and two below
the dam. DNA was extracted from the tissue clippings and the mitochondrial
gene ND1 was sequenced. Preliminary data indicate the percent of
polymorphic sites to be 3.30% for L. cardium and 8.44% for Q. pustulosa.
From 42 L. cardium samples, 19 different haplotypes were present, versus
27 haplotypes from 35 Q. pustulosa samples, indicating that for ND1 Q.
pustulosa is more genetically diverse than L. cardium.
P3.77 TAMONE, SL*; CHUNG, JS; University of Alaska Southeast,
UMBI-Center of Marine Biotechnology; [email protected]
SEQUENCE ANALYSIS OF CRUSTACEAN HYPERGLYCEMIC
HORMONE FROM TANNER CRAB CHIONOECETES BAIRDI
Crustacean hyperglycemic hormone (CHH) is an eyestalk neuropeptide
secreted from sinus glands that functions in the regulation of circulating
glucose. This neuropetide is important for crustacean metabolism and should
serve an important role in animals under environmental stress; animals that
have increased metabolic rates to compensate for environmental change.
Crustacean hyperglycemic peptide has been purified from multiple
brachyuran crab species to date, but not from the cold water Tanner crab,
Chionoecetes bairdi, a species found in Alaskan waters. The purpose of
purifying and sequencing C. bairdi CHH is to establish tools for further study
of cold water crab metabolic physiology. Cold water crabs such as those in
the genus Chionoecetes are currently a good model for understanding the
role that climate change and associated water temperature changes might
have on metabolic physiology. Sinus glands were dissected from male C.
bairdi and the neuropeptides were purified using reverse-phase HPLC. Two
neuropeptides were identified as CHH with an enzyme-linked
immunosorbant assay (ELISA) using a heterologous antibody specific for
Callinectes sappidus CHH. The bioactivity of these two peaks was assessed
by injecting CHH containing samples into eyestalk-ablated Tanner crabs and
measuring subsequent circulating glucose. The full length cDNA sequence of
the larger eyestalk CHH from C. bairdi was determined through amplification,
cloning and sequencing of first strand cDNA and was subsequently
constructed from overlapping clones. A phylogenetic analysis of amino acid
sequence data from six brachyuran crab species showed C. bairdi CHH most
closely related to the majid crab, Libinia emarginata (P55688). Future studies
will include comparative metabolic physiology with the warm water crab C.
sappidus.
e313
P3.121 TANKERSLEY, R.A.; LOPEZ-DUARTE, P.C.*; Florida Institute of
Technology, Scripps Institution of Oceanography; [email protected]
Exorcising Statistical Demons: Interactive Tutorial (StatTA) Promotes
Statistical Literacy and Supports Inquiry-based Instruction in Biology
Recent curricular reforms for teaching introductory statistics focus on
providing students with practical experiences with data and training in the
use of computers to explore fundamental concepts of exploratory analysis
and inferential testing. Although computers and statistical software have
freed students from the computational drudgery associated with performing
many tests, students still struggle with selecting and performing the
appropriate statistical analysis, interpreting results, and understanding the
connections among procedures. We addressed these pedagogical
challenges through the development of a web-based, interactive instructional
program (StatTA) that fosters statistical literacy by improving student
competency and proficiency in practicing statistics. The program is designed
to support inquiry-based and problem-based activities in biology and includes
interactive exercises and tutorials, demonstrations, and self-test activities
that help students select and perform statistical procedures, identify the
relationships among tests, and master the art of statistical thinking and
practice. StatTA enables instructors to focus on conceptual statistical
thinking and interpretation rather than the steps and procedures necessary to
perform a test. Thus, students spend less time learning statistical software
and completing computational recipes and more time learning how scientists
and statisticians approach problems and interpret statistical results.
Evaluation results indicate the program is effective in helping students
conceptualize the relationships among statistical tests and apply appropriate
statistical procedures to novel research problems.
P3.126 TANKERSLEY, R.A.*; WINDSOR, J.G.; Florida Institute of
Technology; [email protected]
Taking It to the Streets: SEAS Mobile Laboratory Exposes Students to
the Excitement of Ocean Science Research
The Integrated Science Teaching Enhancement Partnership (InSTEP) is part
of the NSF's Graduate Teaching Fellowships in K-12 Education (GK-12)
Program and is designed to foster student interest in science while boosting
teacher confidence in science content and inquiry-based instruction. Each
year, graduate students from Florida Techs science departments are
matched with local high school teachers to design and pilot a series of lesson
plans linking core content areasEarth science, biology, chemistry and
physics. To support field-based activities, InSTEP recently renovated a 35 ft
recreational vehicle that serves as a mobile laboratory (Science Exploration
at Sea - SEAS Lab). SEAS seeks to improve ocean literacy by exposing
students to the tools and techniques used by marine scientists. The lab also
gives schools access to equipment and resources they would otherwise be
unable to afford. The lab can accommodate up to 12 students and includes
22 ft of bench space, five computers, a GPS unit, filtered seawater, and a
multi-sensor weather station. The lab also contains state-of-the-art research
equipment for conducting experiments and analyzing samples at local field
sites, including microscopes, balances, sampling gear, water test kits,
multi-probe meters, and spectrophotometers. On-board computers have
access to online resources, including real-time data available through
Floridas Coastal Ocean Observing System. Imaging hardware and software
associated with the microscopes enable students to capture and analyze still
images and video. Three one-day modules focusing on the biology of
horseshoe crabs, feeding adaptations of marine organisms, and coastal
weather are currently being developed and piloted. Supported by NSF Grant
Nos. DGE 0440529 and 0638702.
P2.176 TAPLEY, D.W.; Salem State College, MA; [email protected]
Patterns of Antioxidant Defenses Vary Among Zooxanthellate
Symbioses
Cnidarian hosts experience hyperoxia as a result of photosynthesis by their
endosymbiotic zooxanthellae. As a result, these hosts experience elevated
exposure to reactive oxygen species (ROS), including superoxide, hydrogen
peroxide, and the hydroxyl radical. The primary defenses against ROS in
most metazoans include the enzymes superoxide dismutase (SOD) and
catalase (CAT) as well as several low-molecular-weight organic molecules
such as ascorbate, glutathione, and urate. Some cnidarian hosts, such as
sea anemones in the genus Aiptasia, do not regulate activities of SOD and
CAT in response to artificially elevated oxygen tensions or acclimation to
increased light intensities. In fact, SOD activity is remarkably low in this
genus. Other cnidarians, however, such as the temperate sea anemone
Anthopleura elegantissima, do regulate some of these enzymes. The primary
defenses against ROS in Aiptasia spp. appear to be saturating
concentrations of uric acid, a potent scavenger of hydroxyl radicals, and
constitutively elevated activities of CAT. Furthermore, CAT activity is
inversely correlated with acclimation irradiance, indicating that direct
photoinactivation of catalase in this symbiosis occurs. Given that defenses
against ROS in other cnidarian zooxanthellate symbioses follow different
patterns, including more robust enzymatic defenses, studies of such
defenses among symbiotic cnidarians need to consider the exact pattern of
defenses for the species under consideration.
P3.8 TATE, KB*; EME, J; CROSSLEY II, DA; University of North Dakota,
University of California, Irvine; [email protected]
Assessing the capacity for sympathetic control of cardiovascular
physiology in embryonic snapping turtles (Chelydra serpentina)
Control of cardiovascular function during development of amniotic
vertebrates remains poorly understood, particularly for reptiles. We have
previously determined that an active cholinergic and adrenergic tone on
cardiovascular function is present late in the embryonic development of
snapping turtles. However, the source of the adrenergic tone, whether
circulating hormones or the autonomic nervous system, is unknown. In this
study, sequential pharmaceutical sympathectomy and receptor blockade was
utilized to isolate the source of the adrenergic tone in embryonic snapping
turtles. Initially, pharmacological sympathectomy with 6-hydroxydopamine
increased arterial pressure, which remained elevated for the duration of the
experiment, while heart rate transiently increased. This treatment was
followed by injection of receptor blocking agents. Administration of the
muscarinic antagonist, atropine, increased heart rate and had minimal impact
on arterial pressure. The beta-adrenergic antagonist, propranolol, induced a
marked decrease in heart rate, while arterial pressure transiently increased.
Finally, administration of the alpha-adrenergic antagonist, phentolamine,
caused a marked decrease in arterial pressure without affecting heart rate.
Collectively, data support the previously established presence of cholinergic
and adrenergic tone in this embryonic reptile, and suggest that the
adrenergic response may originate primarily from circulating catecholamines
in snapping turtle embryos at 90% of development.
e314
P3.27 TAYLOR, K.N.*; WEIGAND, K.L.; BAATZ, J.E.; DEAROLF, J.L.;
Hendrix College, Conway, AR, the Medical University of South Carolina,
Charleston; [email protected]
Can the maternal weight of a guinea pig be used to determine the
glucocorticoid steroid dose to its fetuses?
Glucocorticoid steroids accelerate the development of body organs before
birth and are therefore given to mothers who are expected to give birth
prematurely, primarily to stimulate the development of their fetuses lungs.
However, from previous studies, we hypothesize that prenatal
glucocorticoids will decrease the percentage of fast twitch fibers in the
breathing muscles of guinea pigs, which would affect the ability of these
muscles to contract quickly during ventilatory challenges. To test this
hypothesis, a steroid dosage protocol based on a study in fetal sheep was
used, in which the mothers weight determined the amount of steroid
administered (0.5mg steroid/kg maternal weight at 65%, 75% and 85%
gestation). But, given that maternal weight is not a good indicator of litter size
in guinea pigs, it is not known if all of the fetuses in this study have received
the appropriate steroid dose. Since glucocorticoids stimulate lung surfactant
production, the presence of these proteins can be used to determine if the
fetuses have received this dosage. Lung samples were collected from all
fetuses in the study and prepared for SDS-polyacrylamide gel
electrophoresis. Proteins were separated using nonreducing conditions on a
12% Tris/Glycine SDS-PAGE gel, run at 200V for 40 minutes and transferred
(25V, 80 min) to nitrocellulose membranes for Western Blots. Membranes
were probed with an anti-lung surfactant protein B (SP-B) primary antibody
and developed using chemiluminescence. Relative changes in SP-B as a
function of glucocorticoid exposure were then used to determine the validity
of using the mothers weight as a basis for the dosage of these steroids in
animals that give birth to litters.
P3.156 TEARE, Amber*; ROSTAL, David; MARLEY, Philip; MOSS, Amanda;
Georgia Southern University; [email protected]
Reproductive Biology of the Alligator Snapping Turtle (Macrochelys
temminckii)
Knowledge of a species biology is necessary for a better understanding of its
phylogeny, as well as for more successful conservation and management.
Reproductive biology is especially important in comprehending the fitness
potential of individuals and growth potential of populations. Reptiles allow for
unique inquiry in the field of reproductive biology due to their long life spans
and late sexual maturity. Freshwater turtles are often studied as models of
ectothermic reproduction. The alligator snapping turtle is a slowly-maturing,
low fecund, freshwater turtle that, despite overwhelming trapping during the
1960s-1980s, has been understudied. Being confined to river systems that
drain in the Gulf of Mexico, this species may be more severally impacted by
habitat destruction and environmental modification. Early studies on M.
temminckii demonstrated basic reproductive similarities to other turtles,
particularly its sister species Chelydra serpentina. However, practically
nothing is known about alligator snapping turtle reproductive ecology or
physiology, especially with respect to hormonal seasonality. The Flint River,
Georgia population of alligator snapping turtles is under study to delineate
their reproductive hormone cycle, gonadal development, egg production and
nesting attributes. Seasonal estradiol, testosterone, and corticosterone
cycles will be examined via ELISA. Individuals will also undergo ultrasound,
x-ray and laparoscopy to determine reproductive status. Nests will be
collected to reveal hatching success and sex ratios. These findings will allow
for comparisons among testudines, particularly Chelydridae, and for more
accurate management techniques for this threatened species.
P3.144 TEMKIN, M.H.*; MISERCOLA, B.; SONAGERE, M.; DIXON, E.; St.
Lawrence Univ; [email protected]
Homebox gene characterization and expression in developing zooids of
the marine bryozoan Membranipora membranacea
Bryozoans are a large group of colonial invertebrates that live in marine and
freshwater habitats. New individuals, or zooids, of a bryozoan colony are
added through a process of asexual budding. As each zooid forms, it
develops specific structures along its anteroposterior axis. During animal
development, regions of the body along the anteroposterior axis are
specified through the biochemical environment established by transcription
factors that are coded for by homeobox genes, including a subclass of
homeobox genes called Hox genes. Initial steps in understanding how
bryozoan zooids establish structures along their anteroposterior axis are to
characterize their homeobox genes and to determine the expression of these
genes during the differentiation of asexually budded individuals. Here we
present data on the full protein coding sequences of four homeobox genes
expressed during the development of zooids in colonies of the marine
bryozoan Membranipora membranacea. These genes are the anterior Hox
gene Deformed (Dfd), the central Hox gene Lox5, the posterior Hox gene
Post-2, and the EHGBox gene Gbx2. Initial sequences for these genes were
obtained by PCR using primers complimentary to conserved homeobox
regions of genomic DNA. Using primers based on these conserved
homeobox regions, the mRNA sequences of these genes were obtained by
3' and 5' RACE. RT-PCR was used to confirm that the sequences obtained
from 3' and 5' RACE belonged to the same mRNA. Based on these mRNA
sequences probes were synthesized for visualizing gene expression in
developing zooids using in situ hybridization.
P3.92 TEW, Whitney Y.*; SECOR, Stephen M.; University of Alabama;
[email protected]
Actin polymerization underlies the postprandial lengthening of the
pythons microvilli
Pythons experience with feeding dramatic upregulation of intestinal function
that appears to be explained in part by the unprecedented lengthening of
their intestinal microvilli. Within 24 hours after feeding, the microvilli have
increased in length by as much as 5-fold. This increase in length and surface
area matches the postprandial increase in nutrient transporter and enzyme
activities. We hypothesized that an underlying mechanism of microvillus
growth is the rapid polymerization of filamentous actin (F-actin), the internal
skeleton of the microvilli, from cytoplasmic globular actin (G-actin). To
demonstrate the postprandial mobilization of G-actin and the formation of
F-actin with microvillus lengthening, we labeled with fluorescent probes both
G-actin (DNase 1) and F-actin (phalloidin) of the intestinal epithelium of
fasted and fed Burmese pythons. Fasted pythons exhibited a high
concentration of cytoplasmic G-actin, whereas for fed pythons, G-actin
concentrations were less and F-actin was highly concentrated at the
brushborder membrane. To experimentally test the role of actin
polymerization in postprandial microvillus growth, we infused either
cytochalasin D, an inhibitor of actin polymerization, or DMSO, a control, into
the intestinal lumen of digesting pythons. We observed a significant
reduction (40-50%) in the length of the microvilli following 24 hours of
infusion with cytochalasin D compared to snakes infused with DMSO or
those fed without infusion. In addition to being shorter, microvilli exposed to
cytochalasin D were irregular in shape and bent. We suspect that feeding
triggers the mobilization of G-actin molecules and other cytoskeletal proteins
from the cytoplasm to rapidly lengthen the microvilli. Upon the completion of
digestion, these steps are apparently reversed to shorten the microvilli.
e315
P2.170 THERRIEN, Corie; WIBBELS, Thane*; University of Alabama at
Birmingham; [email protected]
Effect of incubation temperature on the morphology and endocrinology
of the reproductive tract of a turtle with temperature-dependent sex
determination.
The differential fitness hypothesis suggests that temperature-dependent sex
determination could be advantageous because it allows the matching of sex
to fitness. The current study addressed the potential physiological
mechanism by which temperature-dependent sex determination (TSD) might
affect fitness. The effects of specific incubation temperatures on the
morphology and endocrinology of the gonads and reproductive tracts were
examined in the red-eared slider turtle (Trachemys scripta). Gonads and
reproductive tracts were compared between late-stage embryos incubated at
temperatures that produced either 1) all females, 2) mostly females, 3)
mostly males, or 4) all males. The gross morphology and histology of the
reproductive tracts of these four groups were compared and the testosterone
and estradiol-17B content were measured. The results indicate significant
variation between the gonads of females incubated at different temperatures
and moderate differences in the males. The results show morphological and
physiological variation in the gonads of from turtles incubated at different
temperatures. These findings provide a potential mechanistic basis for the
differential fitness hypothesis. Further, the results provide insight on optimal
incubation temperatures for turtle conservation programs that artificially
incubate eggs.
P1.20 THOMAS, N.M.*; FRISBIE, J.; SNOAP, T.; BERGMAN, D.A.; Grand
Valley State University; [email protected]
The Distribution of Crayfish Species in the Tributaries of the Grand
River, MI
Invertebrate animals make up the greater part of the world's biological
diversity and are present in about all habitats, where they perform essential
ecological functions. Their survival is fundamental to the maintenance of life.
Large numbers of invertebrate species are under severe threat of extinction,
or are already extinct due to the extreme transformations that habitats have
suffered due to human activities. Crayfish are one such important
invertebrate under pressure and applying pressure to other organisms in
ecosystems. Crayfish are keystone species in most aquatic systems.
Keystone species are those species that are most important in shaping the
total ecology of a system. Crayfish are often keystone species because they
are an important resource for many other animals and can affect species
diversity and abundance directly. Specifically, crayfish can adversely affect
systems by removing plants from an aquatic system making the water turbid,
and prey on fish eggs reducing their numbers. There are over 415 species of
crayfish in North America. It is recognized that at least eight species of
crayfish are found in the state of Michigan. For these reasons, crayfish are
an important organism to study. We examined crayfish biodiversity and
distribution within the Grand River drainage system. Our study identified
three species of crayfish in the Grand river system, as well as the invasive
zebra mussel that could alter crayfish populations.
P3.17 THOMSON, Amy*; VATNICK, Itzick; BAKER, Patrick; Widener
University, Swarthmore College; [email protected]
Estimate of Survival Time of Diamondback Terrapins Caught in Crab
Traps Based on Voluntary Dive Times and Metabolic Rates
Mortality in commercial crab traps has contributed to the decline of local
populations of the diamondback terrapin, Malaclemys terrapin. It is unknown
how long a terrapin can survive after entering a submerged crab trap. For
this reason, behavioral and physiological analyses were conducted to
estimate survival time. Average (Mean +/- SD) voluntary dive time (8.4 +/5.7 min; n = 9) of captive terrapins was determined by videotaping animals in
the laboratory. Females (9.2 +/- 6.8 min; n = 5) generally had longer dives
than males (7.4 +/- 3.4 min; n = 4) and dive length was not correlated with
body mass. The longest voluntary dive was 50 minutes. In contrast, the
average time of submergence for seven crab traps set in tide creeks over a
4-day period was 58 +/- 54 min for morning high tides and 314 +/- 61 for
evening high tides. Oxygen consumption was determined at 10, 20 and 30
°C. As expected, metabolic rate increased with temperature (Q10 = 1.73).
Using mass-specific lung volume and metabolic rates, it was calculated that
a ~200g terrapin in this study had enough oxygen stores to sustain aerobic
metabolism for ~ 11 min at 25°C. Therefore, our data seem to indicate that
voluntary dives in the laboratory are terminated before the anaerobic diving
threshold has been reached. Because commercial crab traps are likely
submerged for several hours at high tide, terrapins that are accidentally
caught in these traps must rely extensively on their ability to sustain
anaerobic metabolism to avoid drowning.
P2.94 TIGREROS, Natasha*; LEWIS, Sara; Tufts University;
[email protected]
Using artificial selection to determine how sexual size dimorphism
affects within-sex size variation
An important issue concerning the evolution of sexual size dimorphism is that
strong genetic correlations between the sexes constitute a genetic constraint.
Although females may be subject to fecundity selection for larger body size
and males for small body size, the evolution of sexual size dimorphism could
be constrained by genetic correlations between the sexes. Thus, selection
for sexual size dimorphism coupled with genetic correlations between the
sexes may help maintain body size variation within each sex. Using artificial
selection on red flour beetles (Tribolium castaneum), we tested the prediction
that selection for extreme sexual size dimorphism will broaden within-sex
variation in body size. We established 3 replicated selection lines: a)
increased female-biased sexual size dimorphism b) reduced sexual size
dimorphism and c) control line. We assessed T. castaneum body size via a
multivariate approach based on principal component analysis of five linear
measures: head width, pronotum width, tibia length, prosternum width and
third abdominal sternite length. After three generations of selection, we
compared the effect that increasing or decreasing sexual size dimorphism
had on intrasexual variation in body size. These results provide new insight
into the evolutionary significance of sexual size dimorphism.
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P2.130 TJIONAS, G*; PATI, A; HOCHBERG, R; Univ. Massachusetts
Lowell; [email protected]
On the structure and function of larval muscular systems in trematodes
(Platyhelminthes: Neodermata): intramolluscan stages from sporocyst
to metacercaria.
Freshwater molluscs serve as intermediate hosts for trematodes that
parasitize amphibians, birds, fish and other vertebrate animals. An individual
snail can harbor multiple larval stages of a single trematode species or even
multiple species. Different species and ontogenetic stages of intramolluscan
trematodes often show characteristic behaviors (movement patterns) that
may be correlated with their body shape and the architecture of their
muscular systems. Patterns of musculature may also be of systematic
relevance. To date, few studies have examined muscle pattern diversity
within a clade or even the ontogeny of a single species - from sporocyst to
redia to cercaria and metacercaria. To understand how muscle patterns may
differ between systematic groups, or even within the ontogeny of a species,
we examined multiple larval stages of select trematodes from the pulmonate
hosts, Menetus dilatatus and Physa sp., using fluorescent phalloidin stains
and confocal laser scanning microscopy. Our results reveal similarities in
muscle arrangement among comparable larval stages, and interesting
differences between larval stages within a single species. This study
underscores the need for greater attention to larval morphology (beyond
taxonomic characters) to understand the functional significance of different
muscle patterns and their importance for trematode systematics.
P2.29 TODD, Nancy E.*; MONTELLO, Maxine; Manhattanville College;
[email protected]
The potential for disruption of aggressive behavior in female by
environmental estrogens
The Siamese Fighting Fish, Betta splendens is a popular aquarium fish, and
is known for its aggressive behavior. Males cannot be kept more than one to
a tank, but many hobbyists and pet stores keep multiple females together,
not thinking they are very aggressive. Recent research at Manhattanville
suggests otherwise, that females are just as aggressive as the males of the
species, and will actively defend their territory. In the wild, these fish live in
flooded rice paddies and other stagnant bodies of water in Asia,
environments that are potentially susceptible to contamination with chemicals
containing estrogenic compounds such as pesticides, waste chemicals from
factories, and other non-point sources. The effects of these estrogens on
aggressive behavior is studied here. Female Betta splendens were exposed
to 2.5ul of 17B estradiol for 28 days to evaluate the effect on their aggressive
behavior. Females were visually exposed to male and female controls for
behavioral observation pre-treatment, 28 days after treatment, and 28 days
after treatment was ended. The control females showed no difference in
behavior before and after treatment, but females treated with 17B estradiol
exhibited a statistically significant difference before and after treatment and
28 days after treatment ceased. All observed behaviors differed in frequency,
not just a few. This indicates that environmental estrogens can decrease
aggression in females, and can ultimately affect their dominance hierarchy
and reproductive success.
P1.11 TORREY, K.W.*; BAKER, P.J.; Swarthmore College;
[email protected]
Plastron redness in Red-bellied Turtles as an index for fitness
Carotenoid-based ornamentation is thought to be an honest signal of health
in many vertebrate taxa; however, this relationship has not been studied in
turtles. The Eastern Red-bellied Turtle, Pseudemys rubriventris, displays
carotenoid pigments as ornamentation on its plastron, (ventral shell);
carotenoids may also be used, however, to protect the body from oxidative
damage. One hypothesis is that because vertebrate animals cannot
synthesize carotenoids de novo, their use for ornamentation demonstrates
that oxidative defense needs are met and exceeded. To test our hypothesis
that there is a relationship between plastron coloration and fitness, we
matched principle components analysis of color values with data from assays
measuring two indices of fitness, the carotenoid content and antioxidant
capacity of plasma. We devised an inexpensive and effective way to quantify
plastron coloration, by capturing digital images of turtle plastrons (n=8) under
standardized conditions and lighting. From these images, measurements of
hue, saturation, and brightness (HSB) were found by sampling randomized
points on a grid overlay of the plastron. Analyzing the HSB values yielded a
first principle component (PC1) that accounted for 79.3% of the variability in
the HSB color space. PC1 correlated strongly with hue, (r2=0.687) saturation,
(r2=0.866) and brightness (r2=0.786). Preliminary analysis has not indicated
a relationship between PC1 scores and plasma carotenoid content, though
further analysis will explore this connection. However, we found a strong
correlation between PC1 scores and total antioxidant capacity of plasma
(r 2 =0.583), supporting our hypothesis and suggesting that a relationship
indicative of honest signaling may exist between plastron coloration and
fitness in Red-bellied Turtles.
P2.146 TORVUND, M.*; YAGER, D.D.; Univ. of Maryland, College Park;
[email protected]
Central nervous system responses to stimulation of the mesothoracic
cyclopean ear of the praying mantis, Pseudocreobotra ocellata
Most praying mantises detect ultrasound using a single ear in the ventral
midline of the metathorax. This provides early warning of a bat attack and
triggers an effective evasive response. A few mantis lineages have evolved a
second, serially homologous, mesothoracic auditory system tuned to 2-4 kHz
sounds. Based on extracellular recordings using 2.5 kHz stimuli at 15-25 dB
over threshold, information from the mesothoracic ear ascends via at least
two interneurons with high conduction velocities and arrives in the cephalic
ganglia 17-24 ms after stimulus onset. A rapid pathway is indicated by
activity in three or more interneurons descending from the cephalic ganglia
only 25-30 ms after the stimulus, which suggests minimal intermediate
processing. These descending responses habituate strongly. A slower
pathway is indicated by a weakly habituating descending interneuron with
very large spikes in the extracellular record and latencies of 50-70 ms. The
tuning curves for the descending units are identical in shape to the
ascending units' curves, but the thresholds are 15-20 dB higher (means of 68
dB SPL vs. 50 dB SPL at 2.5 kHz). In addition, at least three axons descend
from the mesothorax into the abdomen. Average latencies at 15-25 dB over
threshold recorded between the 2nd and 3rd abdominal ganglia ranged from
14-20 ms. There was no indication of long-latency activity descending from
the head into the abdomen. Thus, information about 2-4 kHz sounds is
widely and very rapidly distributed throughout the CNS and a separate
slower processing pathway probably exists as well. This is a pattern
commonly seen in arthropod escape systems where behavioral latencies are
typically 40-80 ms. Nonetheless, attempts to elicit behavioral responses to
diverse 2-4 kHz stimuli in a broad range of contexts were not successful. The
behavioral role of mantis mesothoracic hearing remains unknown.
e317
P2.138 TOTTEN, D.C.*; WEIGAND, K.L.; DEAROLF, J.L.; Hendrix College,
Conway, AR; [email protected]
Does myosin heavy chain expression in intercostal muscles of Cavia
porcellus vary with exposure to betamethasone?
Premature infants are at a higher risk of complications due to a lack of
development of the organs associated with ventilation and gas exchange, so
glucocorticoids, like betamethasone, are used in the medical community to
accelerate the development of the lungs. However, the effects of these
steroids on breathing muscle development are currently unknown. Since
these steroids are known to stimulate differentiation, we hypothesize that
treated muscles will express more adult fast (neonatal, IIa, IIx) myosin heavy
chain (MHC) isoforms than control groups. To test this hypothesis, pregnant
guinea pigs underwent two steroid injection protocols. In the short protocol,
females had two injections at 70% gestation 24-hours apart, while the long
protocol had females injected at 65%, 75%, and 85% gestation, two
injections per week, 24-hours apart. Intercostal muscle samples were
collected from all fetuses and extracted with an urea/thiourea buffer.
Extractions were separated in SDS-polyacrylamide (7%) gels run at 275 V
and 8°C for 24-hours. After being silver stained and dried, the gels where
analyzed with Scion Image to determine the average proportions of fetal,
neonatal/IIa/IIx, and slow MHC isoforms relative to the total myosin present.
In the short protocol, treated muscles expressed significantly less fetal
(46.1+/-2.5%) and more adult fast (36.2+/-2.2%) than controls (49.7+/-0.7%;
30.3+/-1.3%). In comparison, the treated muscles in the long protocol
expressed significantly more fetal (27.7+/-1.9%) and less adult fast
(46.8+/-3.8%) than controls (22.8+/-2.9%; 58.2+/-4.2%). The results from the
short protocol support our hypothesis that betamethasone accelerates
muscle development, which suggests that the intercostals of treated
neonates will be better prepared for function at birth.
P2.45 TRAN, Cawa*; HADFIELD, Michael G.; University of Hawaii at Manoa;
[email protected]
The receptor and signal-transduction pathway that mediate planular
settlement of the coral Pocillopora damicornis
Larvae of the scleractinian coral Pocillopora damicornis are induced to settle
and metamorphose by the presence of marine bacterial biofilms. The
swimming planula requires this natural cue to select a suitable substratum,
attach and grow into a benthic polyp. However, not all bacteria are inductive,
and the inductive capacity of each strain is highly species-specific. Induction
is mediated by a receptor that detects the external cue and triggers a
signal-transduction pathway that initiates metamorphosis. The primary goal
of this study is to determine what type of receptor and signal-transduction
pathway are involved during metamorphosis of P. damicornis, a basal
metazoan, to better understand metamorphosis of invertebrate larvae.
Evidence from studies on larvae of hydrozoans and another anthozoan
suggest that G protein-coupled receptors (GPCRs) and fibroblast growth
factors (FGFs), respectively, are good candidates. In addition, other possible
receptor types include lectins and ligand-gated ion channels. Preliminary
results suggest that a mannose-binding lectin is localized in the apical region
of the larvae of P. damicornis. Current experiments include settlement
assays in which competent larvae are exposed to neuropharmacological
agents that affect a specific type of receptor and/or pathway, in the presence
and absence of biofilm. Agents tested here induce, inhibit, or do not affect
metamorphosis of these larvae. This study provides insight into the
underlying physiological mechanisms that regulate metamorphosis in the
larvae of P. damicornis, in comparison to other invertebrate taxa.
P2.39 TRAYLOR-KNOWLES, Nikki G.*; HANSEN, Ulla; KAUFMAN, Les;
FINNERTY, John R.; Boston University; [email protected]
The Evolutionary Diversification of LSF and Grainyhead Transcription
Factors Preceded the Cnidarian-Bilaterian Split
The LSF/Grainy head (GRH) transcription factors are critical during both
development and homeostasis, being involved in regulation of cell cycle, cell
division, and cellular differentiation in a range of developmental and
non-developmental contexts. The LSF/GRH family is split into the LSF/CP2
subfamily and the GRH subfamily, which can be distinguished by their
distinctive oligomerization domains and differences in their oligomerization
behavior. In order to understand the functional evolution of LSF and GRH, it
is necessary to identify the ancestor in which the original gene duplication
occurred. This will allow us to reconstruct the functional repertoire of the
LSF/GRH ancestor, and to compare this inferred ancestral condition with the
function of LSF and GRH in a phylogenetic progression of extant taxa. By
doing a bioinformatic query of newly available genomes, including Monosiga
brevicollis, Trichoplax adhaerens, Amphimedon queenslandica, Volvox
carteri and several fungi, we have found that the origin of a distinct LSF and
GRH subfamilies predated the diversification of triploblasts into distinct
protostome and deuterostomes lineages and appears to have ancestral
proteins present in algae and fungia much more distant evolutionary past
then previously thought. We report the identification of LSF/GRH family
members in 23 species, including basal metazoans, fungi, and algae. MEME
analysis was used to identify conserved protein domains within LSF/GRH
family. Interestingly, Nematostella vectensis seems to display two potential
loci for GRH-like genes, and most surprisingly Volvox carteri has shared
conservation of the DNA binding domain of this family, indicating that this
gene is truly an ancestral gene of metazoan LSF/GRH family.
P1.94 TSE, J.C.*; JONG, P.; HINTERWIRTH, A.J.; DANIEL, T.L.; University
of Washington; [email protected]
Stimulating antennal muscles leads to path changes in a moths flight
trajectory
Previous work has shown that mechanoreceptors at the base of the
antennae in the crepuscular hawkmoth Manduca sexta are necessary for
stable flight control. They mediate flight responses by acting as vibrational
gyroscopes, detecting Coriolis forces that appear during body rotations
(Sane et al. 2007). We hypothesize that artificially introducing a force that is
applied out of the antenna's vibrational plane should lead to compensatory
reactions and therefore to changes in a moth's flight path. To test this
hypothesis, we created small tungsten electrodes that are implanted in the
dorso-medial side of the scape, targeting specific extrinsic muscles that lead
to antennal retraction (out of the natural vibrational plane). We use a low
current 5 V square wave stimulus generated by an Arduino board at 60 Hz
with a duty cycle tuned to elicit an antennal retraction without suppressing
flight behavior. The stimulus is delivered to the implanted electrodes via a
cable of ultrafine stainless steel wire. Thus moths are loosely tethered to the
stimulator and permitted to fly. Preliminary experiments show that, in 4 out of
14 animals in which electrode implantation was attempted, stimulation of the
left antennal muscles leads to a high probability of left turns immediately
following the stimulus. The direction of the elicited response agrees with
what is expected if antennae act as gyroscopic sensors. These results
provide further evidence that moth antennae are crucial components of a
mechanosensor-mediated flight control circuit.
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P2.6 TUCKER, Mitch*; HUMFELD, Sarah C.; GERHARDT, H. Carl;
University of Missouri, Columbia; [email protected]
Effects of polyploidy on female call preference in gray treefrogs, Hyla
chrysoscelis.
The gray treefrog complex consists of two cryptic species; Hyla versicolor is
a tetraploid (4N=48) species that arose from the polyploidization of its diploid
counterpart, H. chrysoscelis (2N=24) and two other extinct treefrog species.
Speciation via polyploidy is almost instantaneous because polyploid species
are reproductively isolated from their non-polyploid ancestors. However, the
establishment of new polyploid lineages requires assortative mating between
polyploids. Genome duplication has been shown to affect the quality of the
male's species-specific mate-attraction signal (pulse repetition rate), thus
polyploids could potentially be reproductively isolated from their diploid
ancestors as a result of changes in the species communication system. We
are investigating the influence of ploidy on female preferences for
advertisement calls to determine whether polyploidization is a means by
which senders and receivers in a communication system can evolve in
tandem. To answer this question, we have created autopolyploid individuals
and will test the acoustic mate-choice preferences of female polyploids upon
reaching sexual maturity. The experimental tests compare preferences for
call traits that vary between the two species, including call peak frequency,
pulse shape, and pulse rate. We are also testing the hypothesis that changes
in calls and preferences of polyploids are mediated through the influence of
genome size on cellular and/or tissue dimensions by examining the behavior
and cellular dimensions of H. chrysoscelis raised at different larval densities.
We expect to find that polyploidy and cellular dimensions affect the
advertisement-call preferences of female H. chrysoscelis treefrogs,
independent of other factors. We will present preliminary results from these
two sets of experiments including female preferences and effects of larval
densities on cell dimensions.
P1.64 UCHIDA, A.M.*; GREEN, J.; AHMAD, S.; GOLLER, F.; MEYERS,
R.A.; Weber State University, Ogden, UT, University of Utah, Salt Lake City,
UT; [email protected]
Sexual Dimorphism of Syringeal Muscles in Songbirds
Male songbirds typically sing more frequently and more complex songs than
females; in some species females do not sing at all. This behavioral
difference is paralleled by sexually dimorphic syringeal muscle mass, but
whether it is also reflected in syringeal muscle architecture is unknown. Fiber
type composition of these muscles was investigated using myosin ATPase
and immunohistochemistry. Female and male members of 5 oscine species
(European Starlings, Sturnus vulgaris; White-crowned Sparrows, Zonotrichia
leucophrys; Red-winged Blackbirds, Agelaius phoeniceus; Brown-headed
Cowbirds, Molothrus ater; and Bengalese Finches, Lonchura domestica) all
showed similar syrinx muscle fiber morphology, with larger superfast fibers
outnumbering smaller fast fibers (for starlings: superfast fiber mean diameter
31-38m and ~70% of fiber population; fast fiber mean diameter 14-20m and
~30% of fibers). In contrast, Zebra Finches (Taeniopygia guttata) showed
pronounced sexual dimorphism, with males possessing a majority of
superfast fibers (as in the other species examined) and females a majority of
fast. This finding provides a structural explanation for equal twitch durations
in male and female starlings and faster twitch times in male Zebra Finches
relative to females. Whereas female starlings, sparrows, and blackbirds sing
occasionally, female Zebra Finches, cowbirds and Bengalese Finches do
not. Thus the presence of superfast fibers does not parallel the occurrence of
singing in females. These findings suggest that superfast fibers may be a
basal character of the oscine syrinx, or are essential for other vocal or
non-vocal functions. Further investigation of closely related species and
behavior is needed. Supported by NIH grant #DC004390 and WSU.
P2.13 VACCARO, EA*; HOUCK, LD; Oregon State University;
[email protected]
Courtship pheromones modulate female behavior in a plethodontid
salamander
Female sexual receptivity is a behavior at the crux of mechanistic and
evolutionary perspectives of reproductive behavior. Recent work addressing
receptivity has established that plethodontid salamander courtships show a
reduced time to insemination when the female has received male
pheromone. A reproductive Plethodon shermani male has a mental (chin)
gland that produces proteinaceous courtship pheromones, and all 26 species
in its clade employ the same method of pheromone delivery: the male taps
his mental gland on the females nares. Pheromones enter the females nasal
cavity and are shunted laterally to the vomeronasal organ (VNO). This
VNO-initiated pathway likely transmits pheromonal information to sites in the
brain known in other vertebrates to be involved in endocrine regulation and
enhancement of sexual behavior. I investigate three candidate mechanisms
by which male pheromones may augment female receptivity: 1) by
influencing a non-specific state of either stimulation or placidity, 2) by
enhancing a central state of sexual motivation, or 3) by affecting specific
sensorimotor integration mechanisms in individual sensory modalities.
Females treated with pheromone are assayed for enhanced response to
visual and olfactory cues (both male- and food-related), as well as
differences in heart rate, general locomotor activity, startle response, and
foraging activity. By investigating the proximate aspects of a signal-response
system, this study ultimately may provide insights into how the perception of
a chemical signal can induce a specific change in behavior.
P2.34 VALENZUELA, J.J.*; TOMANEK, L.; Montana State University Bozeman, California Polytechnic University - San Luis Obispo;
[email protected]
The Acute and Chronic Heat Stress Response in the Purple Sea Urchin,
Strongylocentrotus purpuratus: A Proteomics Approach
Purple sea urchins (Strongylocentrotus purpuratus) inhabit intertidal zones
where they experience extreme temperature fluctuations. In this study we
used a proteomics approach to characterize the protein expression profiles in
response to heat. We acclimated sea urchins to 11C and 18C for four weeks
and subsequently exposed animals to 25C for 4 hours. Afterwards animals
were brought back to their respective acclimation temperature for a 16 h
recovery period. We excised tube feet tissue immediately after recovery and
homogenized it in urea-containing buffer. Proteins were separated using
two-dimensional gel electrophoresis (2D-GE): first we used an immobilized
pH gradient to focus proteins according to their net charge and, second, we
used sodium dodecyl sulfate- polyacrylamide gel electrophoresis
(SDS-PAGE) to separate proteins according to their molecular weight. Gels
were stained with a fluorescent stain and 2D gels were subsequently
analyzed using image analysis software (Delta2D) to determine which
protein spots are differentially expressed in response to heat. The expression
of 28 proteins (7% of 425 total) changed with acute, and of 25 (6%) with
chronic (acclimation to 18C) heat stress. 12 (3%) protein spots showed an
interaction effect. We are currently using matrix-assisted laser
desorption/ionization tandem time-of-flight (MALDI-TOF-TOF) mass
spectrometry to identify the differentially expressed proteins. These
preliminary results may provide insights into the global response of the sea
urchin proteome to environmentally relevant heat stress following different
thermal conditions.
e319
P1.166 VAN TRUMP, WJ*; STROTHER, JA; FEITL, KE; MCHENRY, MJ;
UC Irvine; [email protected]
The mechanical sensitivity of lateral line receptors in the Mexican cave
fish (Astyanax mexicanus).
Mexican blind cave fish (Astyanax mexicanus) are thought to possess an
enhanced ability to sense water flow as a means of avoiding obstacles in the
dark compared to their river-dwelling relatives. We tested this idea by
measuring the morphology of lateral line receptors, known as superficial
neuromasts, and mathematically modeling their deflections when stimulated
by an oscillatory flow stimulus. This modeling was achieved with a
computation of the fluid-structure interactions between the flow stimulus and
the neuromast. We found that the superficial neuromasts of blind cave fish
do provide enhanced sensitivity to flow when compared with the smaller
neuromasts of the sighted river-dwelling fish.
P3.70 VENKADESAN, M.*; MAHADEVAN, L.; School of Engineering &
Applied Sciences, Harvard University; [email protected]
How to throw accurately
When throwing to hit a target accurately, we preferentially use an underarm
or overarm style depending on how far the target is. To understand why this
might be so, we ask if differences in accuracy between these throwing styles
underlie strategy? Accuracy of a throw is governed by how errors in release
timing and release velocity of the projectile propagate to cause deviations
from the desired target. We quantify this in terms of a simple model of
throwing where the arm is modeled as a controllable hinged bar of length R,
that can release a projectile at any angle with respect to the horizontal (φ)
and angular velocity (ω) of the arm. The parabolic trajectory of the projectile
leads to a parametrization in terms of (φ, ω (φ)) for which the projectile
accurately strikes the target. We quantified the amplification of initial errors
δφ and δ ω, using the largest singular value of the appropriate Jacobian.
Then, the release parameters with the minimum of the largest singular value
correspond to the preferred throw. We find that the style of throwing changes
with increasing target distance and height. For nearby targets at or below the
pivot of the arm, an underarm strategy is preferred. For targets above the
arms pivot and farther away than arm length, an overarm strategy is
preferred. For very far targets, both an underarm and overarm strategy are
almost equally preferred as expected for a model with no strength
differences between an overarm and underarm throw. We present a detailed
exploration of the parameter space of throwing with this simple model and
discuss implications to understanding the motor control of accurate throwing
in humans and other primates.
P3.103 VISHNUVARDHAN, Smitha*; GREENLEE, Kendra J.; North Dakota
State University, Fargo; [email protected]
Tracheal system expression of a matrix metalloproteinase varies
throughout development in the tobacco hornworm, Manduca sexta
Matrix metalloproteinases (MMPs) are a family of highly conserved,
proteolytic enzymes found in most organisms. MMPs can degrade most
types of extracellular matrix protein, making them important enzymes in the
regulation of development. In fruitflies, MMPs are critical for metamorphosis
and important for proper tracheal system development. During the molting
process, MMPs cleave an adhesion molecule releasing the old exoskeleton
from the new cuticle. In this study, we tested the hypothesis that MMPs play
a role in tracheal system molting in Manduca sexta, the tobacco hornworm.
Using zymography, we found active MMPs in isolated tracheae of 4th and
5th instar caterpillars. Tracheae of larvae from both the instars showed
higher proteolytic activity at the end of the instar when compared to the
beginning. In addition, proteolytic bands were also observed in samples of
cuticle from late 5th instar larvae, further supporting the hypothesis that
these enzymes are important for molting and metamorphosis. Recently,
MMPs were identified in another lepidopteran, the waxmoth, Galleria
mellonella. In the waxmoth, MMPs are hypothesized to be important for
immune function, as they are upregulated upon exposure of hemocytes to
bacterial lipopolysaccaride. If M. sexta MMPs are also important for immune
function, then we should find MMP expression in immune-related organs
such as fat body, hemolymph or hemocytes. However, we were unable to
detect any proteolysis in the fat body, suggesting that MMPs present there
may be inactive. Furthermore, MMP activity detected in hemolymph and
hemocytes was found sporadically, indicating that MMP expression in these
tissues may require induction by an immune response.
P1.31 VITAL, Cuauhcihuatl*; MARTINS, Emilia P.; Indiana Univeristy,
Bloomington; [email protected]
Effects of different individuals on information transfer in zebrafish
groups.
Fitness of gregarious individuals is greatly influenced by several aspects of
group phenotype. For instance, individual food intake is directly related to
group foraging success. In this case information transfer plays an important
role in group fitness. The faster information is transferred the higher chances
individuals within a group have of locating food, escaping predators or
acquiring other resources. Little research has been done on what factors
influence information transfer in a social group. We explore the role of
important individuals in information transfer. First we find important and
non-important individuals- as measured by Betweenness Centrality within
zebrafish groups. Second we train these individuals on a specific task to be
tutors for the rest of their own groups. By removing and training important
and non-important individuals we test the relevance of such individuals in
transferring new foraging techniques to a zebrafish shoal. Our results
suggest that socially important individuals play a more influential role in
social learning. Group fitness, thus is greatly influenced by the social
organization. Specifically, socially-important individuals play a key role in
group fitness in activities such as group foraging.
e320
P2.42 VON DASSOW, M.*; DAVIDSON, L.A.; Univ. of Pittsburgh;
[email protected]
Slicing, shocking, and sucking on embryos to differentiate active and
passive mechanical behaviors of developing tissues.
A fundamental problem in the biomechanics of morphogenesis is
differentiating active force generating processes from passive viscoelastic
properties of embryonic tissues. We use micro-aspiration to assay the
apparent stiffness of gastrulating Xenopus laevis embryos in vivo. We apply
suction to a patch of the embryo surface through a 125 micrometer diameter
channel and measure the resulting deformation. Previously we observed that
these tissues occasionally contract with sufficient force to counter the applied
suction (5.4 Pa) over a period of one to several minutes. Rapid, stochastic
contractions are also visible in time-lapse videos of embryos that are
minimally manipulated, just constrained enough to stay in place. If we could
experimentally induce contractions it would open up new means to
investigate the relations between active contractility and passive
viscoelasticity, and to identify potential regulators of contractility in embryos.
We noticed that wounding stimulates contraction in both the wounded
embryo and adjacent embryos. Hence, a diffusible factor released by
wounding can induce contraction. We wondered if electrical stimulation could
also cause contractions. The micro-aspirator channel can serve as an
electrode so it allows measurement of apparent stiffness and simultaneous
electrical stimulation. Stimulating the ~125 micrometer diameter aspirated
tissue with ~0.1 mA for 0.05 to 0.4 ms induced strong contractions. Peak
contraction occurred ~1 min after stimulation, with relaxation occurring over
the following 1 to 2 minutes. Hence, we can now combine mechanical testing
with acute control of contractility, opening up new avenues to experimentally
differentiate active and passive mechanical behaviors in living, developing
embryos.
P2.12 WACK, CL*; SCHUBERT, SN; WOODLEY, SK; Duquesne University;
[email protected]
Endocrine sensitivity to pheromonal signals in a terrestrial salamander,
Plethodon shermani
Behavioral interactions can induce changes in hormone levels. Furthermore,
exposure to social signals involved in behavioral interactions can induce
changes in hormone levels. Many amphibians utilize chemosensory cues as
social signals. To determine whether endocrine status is modulated by
exposure to conspecific chemosensory cues in the plethodontid salamander,
Plethodon shermani, we examined the endocrine response to exposure to
male courtship pheromones. Two studies, conducted in different years under
slightly different experimental conditions, were performed. The first study
measured changes in plasma corticosterone, testosterone and estradiol in
males, reproductive females, and nonreproductive females after exposure to
a saline control and two different chemosensory cues: male courtship
pheromones and female skin secretions. This first study found that exposure
to male courtship pheromones resulted in increased corticosterone in males.
A second study, conducted to confirm the findings of the first experiment,
also found that exposure to male courtship pheromones resulted in
increased plasma corticosterone in males. This is the first evidence that
endocrine status is sensitive to pheromonal signals in an amphibian.
P3.104 WAGNER, N.D.*; FROST, P.C.; RAFFERY, S.P.; Environmental and
Life Science Graduate Program Trent University Peterborough, Ontario,
Trent University Peterborough, Ontario; [email protected]
Nutritional constraints on the innate immune system of the Rusty
Crayfish Orconectes rusticus
We examined the effects of poor food quality on immune function of the rusty
crayfish, Orconectes rusticus. After two weeks of acclimatization to a
laboratory environment, crayfish were fed artificial diets having different
nitrogen (N) and phosphorus (P) levels for 16 days. After this period, we
measured respiratory rates and nutrient excretion to verify physiological
effects of food quality on Orconectes. One the final day of the experiment,
hemolymph from each crayfish was assayed for both phenoloxidase activity
and superoxide production in both unstimulated and LPS-stimulated
samples. All animals were saved for measurements of dry weight and
elemental (C, N, and P) body content. N- and P-content of the diet altered
respiration rates and excretion of crayfish suggesting changes to metabolic
rate and nutrient status of these animals. High N diets increased baseline
superoxide production on a per cell basis and slightly increased
phenoloxidase, however phenoloxidase appears to be more sensitive to P
limitation than to N limitation. Despite low baseline superoxide production,
nutrient-limited animals showed a high level of stimulation from LPS. We also
collected crayfish from streams across eastern/southern Ontario and
measured their immunocompetence as described above. These
measurements showed considerable between-stream differences in crayfish
immunocompetence but generally higher immunocompetence than
laboratory held animals. We show that crayfish immune function is sensitive
to the elemental content of their diet with both N and P being important in
different aspects of immunocompetence.
P1.163 WALGUARNERY, J.*; SCHROEDER, R.; BUTLER, M.A.; University
of Hawaii; [email protected]
Optical geometry, perch orientation, and microhabitat selection in a
sit-and-wait aerial predator, Megalagrion xanthomelas
Habitats of high spatial variation in absolute light levels and spectral quality
present a challenge to animals that rely on visual orientation and visual
target discrimination. Insects, in particular, have several factors working
against consistent visual performance in complex environments including the
lack of a focusing mechanism, relatively limited light capture and coarse
spatial resolution of their compound eyes. Therefore, an understanding of the
morphological and behavioral means by which insects overcome these
limitations in order to perform highly demanding visual tasks is important
both to questions of habitat specialization and visual system optimization.
We investigated optical geometry, perch orientation and microhabitat
selection in the Hawaiian damselfly Megalagrion xanthomelas, a sit-and-wait
predator that intercepts aerial prey among heterogeneous vegetation
bordering streams and wetlands. We found that while the eyes of M.
xanthomelas are roughly spherical, visual acuity appears concentrated in a
region located approximately 15 degrees below the equatorial frontal plane.
This optical geometry corresponds with typical orientations of damselflies
resting on perches and suggests an arrangement maximizing detection of
prey or conspecifics traveling along stream margins. Although available
optical microhabitats differed widely, overall variation and microhabitat
selection could be largely described by single synthetic variables
summarizing total photon flux and relative levels of ultraviolet and infrared
irradiance. We discuss the extension of this research to the development of
explicit evolutionary hypotheses and the use of the diverse, endemic
Hawaiian damselfly genus Megalagrion as a model system for examination
of selective pressures shaping the visual system and influencing visual
ecology.
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P1.38 WALTERS, LJ*; TURNER, T; KUFFNER, IB; PAUL, VJ;
RITSON-WILLIAMS, R; GRABLOW, K; SETTAR, C; RIVERA, G; HICKEY,
TD; Univ. of Central Florida, Univ. of the Virgin Islands, US Geological
Service, Smithsonian Inst.; [email protected]
Coral-Algal-Urchin Interactions in Caribbean Waters
The die-off of the long-spined black sea urchin Diadema antillarum in
Caribbean waters in the 1980s coincided with a dramatic increase in
macroalgal biomass on coral reefs. Scientists and resource managers have
hypothesized that the return of this keystone herbivore will drastically reduce
current algal biomass and enable corals to once again dominate. On reefs in
St. Thomas, United States Virgin Islands, Diadema abundance in shallow
waters has greatly increased in recent years. We are beginning to address
the impact of their recovery by: 1) running in-situ, recruitment assays with
larvae of the hard coral Porites astreoides and dominant macroalgal species
(Dictyota menstrualis, Lobophora variegata, Acanthophora spicifera,
Halimeda opuntia) and 2) looking at survival of coral spat on tiles when
placed in contact with these same macroalgae with and without Diadema
present. Tiles from the different treatments and appropriate controls were
checked after 14 hr (overnight) and at the end of 6 days. While coral
recruitment was significantly impacted by some tested species of
macroalgae (D. menstrualis), any negative effects associated with the
macroalgae, predation or accidental damage was minimal when Diadema
was able forage over the tiles with attached coral spat. Thus, it appears that,
at their present densities, Diadema is not detrimental to the survival of this
common hard coral species. Our data support the hypothesis that Diadema
facilitates coral recruitment by removing chemically active species of
macroalgae.
P2.144 WALTON, D.B.*; PIRTLE, T.J.; Abilene Christian University;
[email protected]
The Effect of Cyclic Nucleotide Dependent Protein Kinase Activity on
Swimming in Clione limacina
Both serotonin and nitric oxide have been shown to increase swimming
speed in reduced preparations of the pteropod mollusk Clione limacina.
Additionally, isoliquiritigenin, an activator of guanylyl cyclase, has a similar
effect as serotonin and nitric oxide in that it enhances swim frequency. On
the other hand, forskolin, an activator of adenylyl cyclase, suppresses
swimming. These results indicate that cGMP accelerates swimming while
cAMP inhibits swimming. We hypothesize that the changes in swim
frequency that occur with cGMP and cAMP are the result of their action on
cyclic nucleotide dependent protein kinases. To test this hypothesis we
applied H-9, an inhibitor of cyclic nucleotide activated kinases. Application of
H-9 had a biphasic effect. Initially, within the first minute of application, H-9
increased swim frequency. A complete cessation of swim activity followed
this initial enhancement. Furthermore, application of serotonin did not
recover H-9 induced inhibition of swim activity. Our results indicate that the
initial enhancement of swimming is a consequence of inhibition of
cAMP-dependent protein kinase and that the termination of swimming that
follows is a consequence of inhibition of cGMP- dependent protein kinase.
P1.102 WANG, D.*; NAVA, S. S.; MORENO, L.; MARTINS, E. P.; Indiana
University and The Center for the Integrative Study of Animal Behavior,
Bloomington; [email protected]
Visual Performance is Lateralized in Male and Female Sceloporus
undulatus Lizards
Behavioral laterality is the specialization of the left or right brain hemisphere
in certain behaviors and functions. Many animals exhibit visual laterality and
asymmetry during social interactions, foraging, and predator detection, i.e.,
the left and right eyes are used differentially for different tasks. For example,
many animals show a left-eye bias during aggression and territorial contexts.
While visual laterality has been shown to occur in many behavioral tasks and
responses involving aggression, little is known whether the left and right eyes
exhibit differential sensitivity, i.e., can one eye see better than the other? We
measured and compared spectral sensitivity to the blue coloration exhibited
by male Sceloporus undulatus lizards from both the left and right visual fields
in adult male and female S. undulatus lizards. We found that left and right
visual fields differ in spectral sensitivity and present here evidence for
sex-specific variation of laterality. Specific results and data will be discussed.
P3.109 WARD, W. Timothy*; KRISTAN, Deborah; California State University
San Marcos; [email protected]
Tapeworm Co-infection Alters Life History and Distribution of the
Nematode Heligmosomoides bakeri
In nature, most hosts harbor more than one parasite species concurrently.
When different parasite species occupy the same site in the host, there may
be direct and indirect effects of one parasite on the other. We investigated if
an established infection with the bile duct tapeworm (Rodentolepis
microstoma) influenced life-history (survival, sex ratio) and habitat selection
(location along the small intestine) of the nematode Heligmosomoides bakeri.
Laboratory mice (Mus musculus) were infected with either 0 (control), 4
(low-intensity group) or 12 (high-intensity group) R. microstoma
cysticercoids. At 21 days post-R. microstoma infection, the same mice were
inoculated with 300 infective stage H. bakeri larvae. Mice were euthanized 6
days post-H. bakeri infection and the following variables were measured for
fourth stage H. bakeri larvae: total number of worms, sex ratio, and location
of larvae along the small intestine. We also determined the number and
mass of R. microstoma, bile duct mass, and circulating alkaline phosphatase
in mouse plasma. Alkaline phosphatase is elevated during bile duct
obstruction associated with liver disease but has not been tested during bile
duct obstruction due to parasite infection. We found that, during tapeworm
co-infection, 57% fewer H. bakeri larvae established (p < 0.0001) and larvae
were located more distally along the small intestine (p < 0.0001) compared to
mice with nematode only infection. There was no effect of R. microstoma on
H. bakeri sex ratio (p = 0.55). R. microstoma infection increased bile duct
mass more than two-fold (p = 0.02), but there was no change in serum
alkaline phosphatase (p=0.19), regardless of the number of adult R.
microstoma (p=0.34).
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P1.75 WASSMER, Gary; Bloomsburg University of Pennsylvania;
[email protected]
Characterization of a Photoperiodically Regulated Protein from a
Woodroach.
The woodroach, Parcoblatta pennsylvanica, is one of the few species of
roach that is able to overwinter at subfreezing temperatures. As winter
approaches, the growth rate of the insects slows and molting ceases.
Laboratory and field studies have shown that this change in post-embryonic
growth rate is photoperiodically regulated, not a direct result of lower
temperature. Other studies have shown that, in parallel with the changes in
growth rate, the concentration of hemolymph proteins is photoperiodically
controlled. Hemolymph concentration increases in response to shortening
daylength. In addition, we see that the types of protein change with
photoperiod. In particular, one hemolymph protein which we have called
DASP (Development Associated Storage Protein) is abundant during long
daylength but unnoticeable when daylength shortens. We believe this protein
to be one in the class of storage proteins in insect hemolymph. This
conclusion is based on several observations that are consistent with the
characteristics of other reported storage proteins: 1) it is very abundant in the
hemolymph, 2) the molecular weight is close to other reported values for
storage protein, 3) the holoprotein is a hexamer, 4) it is not another suspect
apolipophorin, and 5) it is not detectable in the adult male. The results
presented here show further characterization of DASP, including partial
amino acid sequence and suspected homology with other proteins isolated
from insects.
P2.115 WATERS-LINDQVIST, L.G.*; WOLCOTT, T.G.; KAMYKOWSKI, D.;
NC State Univ., Raleigh, NC State Univ, Raleigh; [email protected]
Seeding red tides: behavioral experiments with Plankton Mimics
How are toxic red tides seeded on the west Florida coast? The dinoflagellate,
Karenia brevis, does not form resting cysts. One hypothesis is that "seed"
populations persist in deep water offshore, are advected onshore by
upwelling, and bloom when they have an ample supply of both light and
nutrients. Robot "Plankon Mimics" are testing whether a simple, biologically
rational behavioral model could keep such a seed population of motile algae
deep, and alive, under realistic field conditions. The model, derived from lab
studies and field distributions, uses a clock-driven diel vertical migration
(DVM,) but modulated by in-situ conditions via physiology. The Mimics swim
upward faster when "hungry" for photosynthate (C) and downward faster
when "hungry" for nutrients (N.) The vertical distribution of nutrients near
shore, especially during upwelling, may have several peaks. Offshore it is
very different. Most of the water column is oligotrophic, and cells encounter
significant N only at their DVMs low point when they are in the near-bottom
layer, into which N diffuses from the sediment. In field experiments, Mimics
under "nearshore" conditions exhibited a DVM with the water surface as its
upper bound, while Mimics under "oligotrophic + near-bottom nutrients"
conditions returned to the bottom on each diel cycle. Mimics in nearshore
conditions filled their C and N pools and "divided" in 3-4d (typical of
nutrient-replete cultures) while under oligotrophic conditions about half of
them "died" after 10 days without acquiring enough C and N to divide. This
indicates that physiological modulation of DVM could allow deep offshore
populations to persist, albeit with very low rates of increase, at depths from
which they could be moved inshore during upwelling and seed a bloom.
P1.104 WEEDMAN, J.M.*; NAVA, S.S.; MARTINS, E.P.; Indiana University
and the Center for the Integrative Study of Animal Behavior;
[email protected]
Short-term Environmental Experience Alters the Visual Acuity of Adult
Zebrafish.
Visual plasticity is a mechanism by which the visual system is able to change
or adjust in response to the environment. For fish, environmental factors
such as water turbidity, light quality and intensity, and habitat structure can
greatly influence overall performance of visual function. A growing body of
evidence has shown that during early development the fish visual system
can exhibit considerable plasticity and that the adult visual system tends to
be less plastic and fairly fixed in maturity. Here, we tested for plasticity of the
adult visual system. We tested the effects of short-term visual experience on
the visual performance of adult zebrafish (Danio rerio). Specifically, we
measured visual acuity from adult zebrafish, exposed the fish to one of two
visual treatments (complex and simple) for eight days, and finally
re-measured and compared the visual performance from all fish. We found
that while the visual acuity of adult fish that experienced a simple visual
background changed very little, the visual acuity of adult fish that
experienced a complex visual background significantly improved. Specific
results and data will be discussed. Our findings suggest that the adult visual
system is much more plastic than commonly thought and that researchers
interested in the effects of environmental factors on vision related tasks, such
as foraging, predator/prey detection, communication, should take into
consideration the effects of visual plasticity in the adult visual system.
P2.139 WEIGAND, K.L.*; DEAROLF, J.L.; Hendrix College, Conway, AR;
[email protected]
Prenatal steroids: altering myosin heavy chain isoform expression in
guinea pig diaphragm
Glucocorticoid steroids are given to women at risk for preterm delivery to
induce rapid development of the lungs of their fetuses and decrease the risk
of mortality. Because these steroids stimulate cellular differentiation, we
hypothesize that fetal diaphragms exposed to a steroid (treated) will express
less developmental (fetal) and more adult (fast: neonatal, IIa, IIx; slow: I)
myosin heavy chain isoforms than control (sterile water) fetal muscles. To
test these hypotheses, we investigated 2 protocols in guinea pigs. The short
protocol called for 1 round (2 injections, 24 hours apart) of betamethasone
(0.5 mg/kg maternal weight) injections, and the fetal diaphragm samples
were collected at 70% gestation. The long protocol called for 3 rounds (1
round/week) of injections, and the samples were collected at 85% gestation.
Diaphragm samples from both injection protocols were collected and
extracted using a urea/thiourea sample buffer. SDS-polyacrylamide gel
electrophoresis was used to separate and identify the myosin isoforms (fetal,
neonatal/IIa/IIx and slow) present in these samples. Each gel was silver
stained, dried, and scanned into digital format. Scion Imaging software was
used to quantify the proportion of each isoform relative to the overall myosin
content of the sample. There was no significant difference in the myosin
expression of either control or treated fetal diaphragms in the short protocol.
However, there was significantly more fetal myosin in the muscles of the
treated fetuses ([T] 20.10 +/- 1.23%; [C] 12.73 +/- 2.12%) and less adult fast
myosin ([T] 62.42 +/- 2.24%; [C] 67.12 +/- 1.46%) in the long protocol. Since
fetal myosin has a slower contraction speed than adult proteins, the delay in
development will reduce the ability of the diaphragm to respond to ventilatory
challenges.
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P1.107 WEINER, S.A*; BAUTISTA, G.M.; SANDERS, D.B.; RYAN, J.;
WOODS, W.A.; STARKS, P.T.; Tufts University, Morehouse College,
Northern Essex Community College; [email protected]
Reproductive roles in Polistes dominulus: The cost of maintaining
ovarian development
Polistes paper wasps are an important model system for studying the
evolution of eusociality, because the castes are totipotent, and as such,
workers can reproduce. However, workers and subordinate foundresses
reproduce little if at all on most nests and generally have ovaries that are
much less developed than those of dominant or solitary foundresses. In
order to add to our understanding of why wasps would not maintain fully
developed ovaries, we measured the energetic cost of maintaining
reproductive development in workers and in dominant, subordinate and
solitary foundresses. The resting metabolic rate (RMR) of each wasp was
found by measuring CO 2 production and ovarian development was
determined by measuring average egg. Egg length was correlated strongly
with RMR, indicating that maintaining ovaries is energetically costly. In
addition, egg length relative to headcap width was also correlated with
mass-specific RMR, indicating that it is more energetically costly for smaller
animals (such as workers and subordinates) to maintain highly developed
ovaries. Furthermore, the slope of RMR on egg length was higher for
workers than for foundresses, suggesting that it was more difficult for
workers to maintain larger ovaries. These costs may partially explain why
workers and subordinates do not maintain fully developed ovaries.
P2.140 WERNER, Bianca J*; ROOT, Robert G; Lafayette College;
[email protected]
Does diffusion matter? Assessing the importance of diffusion in
phosphagen metabolism for a fast start
The Phospho-Creatine Shuttle is a buffering system that stores and
transports energy for muscle contractions, among other metabolic
processes. Phosphocreatine (denoted PCr), is a phosphagen that serves a
dual purpose in cells: 1) it acts as an energy reserve, providing large
amounts of energy within short time periods by maintaining a high ATP/ADP
concentration ratio in the A band of myofibrils; and 2) it transports energy to
myofibrils from mitochondria located adjacent to I bands of the myofibrils.
PCr is synthesized in mitochondria, then diffuses into myofibrils. Is this PCr
diffusion fast enough to contribute significantly to maintenance of high ATP
concentration in fully contracting muscles, considering fast starts occur in
10-100 milliseconds? Constructing a mathematical model using parameters
derived from published results of other's experiments, we find that diffusing
PCr does materially assist in buffering ATP.
P2.184 WHITE, Joshua P.*; ROBERTSON, Ian C.; Boise State University;
[email protected]
Seed predation on slickspot peppergrass, Lepidium papilliferum
(Brassicaceae), by the Owyhee harvester ant, Pogonomyrmex salinus
(Hymenoptera: Formicidae)
Owyhee harvester ants (Pogonomyrmex salinus) actively remove fruits and
seeds from slickspot peppergrass (Lepidium papilliferum), a rare mustard
endemic to southwest Idaho. We conducted a study to establish whether P.
salinus is the only major seed predator of L. papilliferum, and to determine
the importance of seed predation as a source of offspring mortality for this
plant. We monitored a total of five L. papilliferum beyond the foraging
distance of P. salinus and found no evidence of seed predation. We then
conducted an experiment to determine the extent of seed predation for plants
located within the foraging distance of P. salinus. A total of 13 pairs of plants
were included; each pair was located within 10 m of an ant colony. One plant
per pair was assigned as the treatment and the other as the control.
Treatment plants were enclosed to bar any ant access. We visited the plants
weekly; counting the number of attached fruits, depredated fruits, and
naturally dehisced fruits on random inflorescences of each plant in the pair.
Plants accessible to ants experienced a direct loss of at least 40% of its fruit
and seed, while plants with no ant access suffered very little seed loss
(ANOVA F1,20=67.60 p < 0.0001). Likewise, ants removed over 90% of seeds
placed on the ground, compared to almost no loss when ant access was
denied (Mann-Whitney U test N=20 p < 0.0001). One hundred percent of
seeds collected by ants (N=100) were returned to the nests and presumably
eaten. A search of 30 midden piles revealed large amounts of empty fruit
husks but no intact seeds. We conclude that harvester ants are the main
seed predators of L. papilliferum, and possibly an important source of
offspring mortality for this rare plant.
P2.141 WHITE, A.J.*; GILLEN, C.M.; NORTHCUTT, M.J.; GAO, Y.;
WHEATLY, M.G.; Kenyon College, Gambier, OH, Wright State University,
Dayton, OH; [email protected]
Effect of cold acclimation on the expression of sarcoplasmic calcium
binding protein (pcSCP1) variants in the freshwater crayfish,
Procambarus clarkii.
We have investigated the effect of cold exposure on sarcoplasmic calcium
binding protein (pcSCP1) from the freshwater crayfish, Procambarus clarkii.
pcSCP1 is an EF-hand calcium binding protein that is highly expressed in
invertebrate muscles where it acts as a calcium buffer. Sequencing of full
length pcSCP1 clones revealed three variants of pcSCP1 (pcSCP1a,
pcSCP1b, and pcSCP1c) that are identical except for a variable region
between base pairs 222 and 345 of the 579 base pair open reading frame.
We assessed expression of pcSCP1 by real-time PCR with variant specific
primers using the relative quantification method and 18s ribosomal RNA as
an internal calibrator. Expression of all three variants was highest in axial
muscle, more than 10,000 fold above hepatopancreas. pcSCP1c was the
primary variant in cardiac muscle where it was expressed about 10 fold
above hepatopancreas. To evaluate expression during cold acclimation,
crayfish were kept at 4 degrees Celsius for 7 days and a control group was
kept at room temperature. Heart pcSCP1 was found to be dramatically
downregulated by cold exposure; all three variants were undetectable after
cold exposure. In contrast, pcSCP1b and pcSCP1c were moderately
upregulated (3 to 7 fold) in axial muscle after cold acclimation. (Funded by
NSF 0445202 and Kenyon College).
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P1.151 WIDDER, P.D.; Virginia Tech; [email protected]
Early testosterone exposure in amphibian eggs: no effects on
development, growth, or behavior
In a variety of egg-laying taxa, steroid hormones have been found to be
maternally transferred to the yolk of eggs. Furthermore, additional studies,
especially in birds, have found that early exposure of the developing embryo
to testosterone can influence development, growth and behavior. I recently
verified that amphibian eggs also contain steroid hormones at laying and that
the amounts of testosterone vary by female; however, the influence of this
early exposure to testosterone on amphibian development, growth, and
behavior is not known. I collected four clutches of freshly laid Rana sylvatica
(Wood frog) eggs and exposed each of them to three different levels of
testosterone for 48 hours. At the end of 48 hours, I sampled a subset of eggs
and, using a radioimmunoassay, verified that the egg hormone levels were
elevated, yet remained within physiological limits. The remaining eggs were
raised to hatching, and time-to and stage-at hatching were recorded, as well
as several morphological variables. After one month of development, at
Gosner (1960) stages 26-27, I measured tadpole activity level, fast start
behavior, and again assessed tadpole morphological variables. Finally, after
two months of development (Gosner stages 30-36), morphology was
assessed a third time. Throughout the experiment, changes in development,
growth, or behavior were never observed relative to testosterone treatments;
however, significant clutch effects were observed in most measures. Thus,
the significance of maternally-derived testosterone in amphibian eggs
remains unclear.
P1.40 WIJESENA, N.*; KUMBUREGAMA, N.S.; WIKRAMANAYAKE, A.;
University of Miami; [email protected]
Investigating the role of Wnt/PCP signaling in the evolution of
embryonic polarity in metazoans
Evolution of mechanisms that established developmental polarity in ancient
animal embryos was likely prerequisite for germ layer evolution, but these
mechanisms are unknown. Extensive use of Wnt/Planar Cell Polarity (PCP)
signaling to generate diverse embryonic polarity events hints that PCP
signaling may have had a primitive role in evolution of embryonic polarity. To
begin to gain insight into this idea we initiated studies to functionally
characterize the core PCP genes in Nematostella vectensis, and identified
NvStrabismus as a localized maternal mRNA. Since Strabismus signaling is
known to antagonize Wnt/β-catenin signaling in bilaterians, we asked if
NvStrabismus has a role in restricting Wnt/β-catenin signaling to endoderm,
thereby mediating germ layer segregation. We will present experimental
results showing that NvStrabismus signaling modulates Wnt/β-catenin
signaling in Nematostella. These findings raise the possibility that interaction
between Wnt/β-catenin and Wnt/PCP pathways played a role in establishing
the embryonic polarity that led to germ layer segregation.
P3.59 WIKTOROWICZ CONROY, A*; DOUBE, M; SHEFELBINE, S;
HUTCHINSON, JR; The Royal Veterinary College, Structure and Motion
Laboratory, University of London; [email protected]
Scaling of the appendicular skeleton: CT scan-based analysis of
whole-bone geometry for clades Proboscidea and Felidae
Most studies of long bone scaling have focused on external measurements
alone, especially for midshaft diameter or circumference and length, and
generally have focused on proximal limb elements only, avoiding the
metapodials and limb girdles for example. Here we demonstrate a technique
using computed tomography (CT) scans to obtain internal and external
geometry and quantify scaling of bone geometry throughout the entire bone,
for all major bones from the girdles to the metapodials. We examine
Proboscidea (elephants), including some data for fossil mammoths and
dwarf elephants, to quantify interspecific and intraspecific scaling at giant
body size and near-columnar limb posture. We also examine Felidae (cats)
to test whether whole-bone geometry changes in order to maintain skeletal
stresses across size, as it has been demonstrated that posture does not
change markedly with size in this clade. Our results refine and expand on
previous studies of these clades, showing that near-isometric scaling
predominates within Proboscidea (but weak positive allometry when viewed
intraspecifically), versus slight positive allometry within Felidae. Our
integrative analysis reinforces the notions that (1) different clades can have
quite unique scaling relationships, (2) bone stresses may differentially be
maintained by a combination of changes in length, diameter and moments of
area, as well as potentially regional bone density, (3) bone strengths or
safety factors may be strongly influenced by regions that are weaker than the
midshaft.
P2.157 WILLIAMS, C.M.*; SINCLAIR, B.J.; University of Western Ontario,
London, Ontario; [email protected]
The effects of continuous and discontinuous gas exchange cycles on
CO2 and H2O production.
When investigating insects that show a variety of patterns of respiration, it
can be very difficult to objectively choose a representative portion of a
respiration trace to evaluate. Erynnis propertius (Lepidoptera:Hesperidae)
overwinters in diapause as a caterpillar, during which time they show both
continuous respiration and discontinuous gas exchange cycles (DGC). This
provides an opportunity to investigate the effects of sample selection and
pattern of respiration on measured CO2 and H2O production and estimated
metabolism. CO2 and H2O production by diapausing E. propertius caterpillars
(n=20) was recorded for four hours at 1 and 8 C after a three hour
acclimation period, and all analyzable sections of data were compared. At 8
C, 40.5 % of individuals showed solely continuous respiration and 47.6 %
solely DGC; but 11.9 % of individuals switched between patterns during the
four hour period. In individuals that had more than one complete
discontinuous cycle, CO2 production did not change over time; however H2O
loss declined throughout the trace. There was no effect of mode of
respiration (continuous or DGC) on CO 2 production, but H 2 O loss was
significantly lower during DGC. All individuals showed continuous respiration
at 1 C, which we attribute to the onset of chill coma. We discuss these
results with regards to the evolution of DGC and suggest some guidelines for
determining standard metabolic rate in insects that exhibit a combination of
gas exchange patterns.
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P2.32A WILLIAMS, S.A.*; COVI, J.A.; MCDONALD, A.A.; CHANG, S.A.;
CHANG, E.S.; MYKLES, D.L.; Colorado State Univ., Fort Collins, UC Davis
Bodega Marine Lab, Bodega Bay; [email protected]
A comparative study of MIH signaling in the brachyuran molting gland
Molt inhibiting hormone (MIH) regulates the production of ecdysteroids by the
crustacean molting gland (Y-organ or YO). Ecdysteroids are hormones that
regulate the physiological process of molting. Upon binding to a membrane
receptor in the YO, MIH induces a second messenger cascade involving
cyclic nucleotides (cAMP and cGMP), which inhibit ecdysteroidogenesis.
Previous studies have used pharmacological agonists in an attempt to mimic
the effects of MIH on YO ecdysteroid secretion in vitro. Adenylyl cyclase
activators, cAMP and cGMP analogs, and NO-donors inhibit
ecdysteroidogenesis in the YO. Moreover, YOs express NO synthase (NOS)
and GC-I. These data suggest that NOS and GC-I are components of the
MIH signaling pathway. The purpose of this study was to determine if
antagonists of the putative signaling components block MIH action in YOs in
vitro. This analysis involves two species of brachyuran crab, Gecarcinus
lateralis and Carcinus maenas. The effects of adenylyl cyclase, NOS, or
GC-I antagonists on MIH-dependent YO inhibition will be reported.
Supported by NSF (IBN-0342982 and IOS-0745224).
P2.93 WILLIAMS, A.S.*; GERHARDT, H.C.; WELCH, A.M.; University of
Missouri, College of Charleston, SC; [email protected]
Nonlinear growth patterns in tadpoles based on parental call length
Females in many species prefer to mate with males bearing showier
ornaments or more energetic displays. Yet, these preferences are not always
linear: bigger is not always better. Female gray treefrogs (Hyla versicolor)
show a nonlinear mating preference, strongly preferring males with long or
medium call lengths, while avoiding males producing very short calls.
According to the good genes hypothesis of sexual selection, females choose
mates in order to obtain high quality genes for their offspring. Genes for high
larval growth rates should help offspring to avoid environmental stresses and
predation and should, therefore, provide a better chance to survive. We
hypothesize that the nonlinear mating preference of female gray treefrogs
reflects nonlinear benefits of mate choice. Specifically, we predict that the
developmental rate of offspring mirrors the nonlinear preference function for
call duration exhibited by females, in that the progeny of males producing
long- and medium-length calls will develop more rapidly than the progeny of
males producing short calls. To test these predictions, we used artificial
fertilizations to cross twenty-seven males with long, medium, and short call
lengths with six females. Five hundred and forty tadpoles were raised
individually in the laboratory. During development, the tadpoles were
subjected to high and low food treatments to test effects of environment on
their development. We weighed the tadpoles at three weeks of age and at
metamorphosis. Preliminary results indicate that progeny of short-duration
callers grew better than progeny of long- and medium-length callers in both
food treatments. Food treatment affected growth for progeny of all parental
call lengths. The nonlinear growth function does not mirror that of the female
preference.
P2.120 WILLIAMS, S .C.*; MCBRAYER, L.D.; Georgia Southern Univ.,
Statesboro; [email protected]
Sources and Consequences of Intraspecific Variation in the Movement
Patterns of the Ambush Foraging Lizard Sceloporus woodi
Movement patterns as they relate to foraging behavior have played an
important role in the understanding of lizard ecology and their evolutionary
history. Surprisingly little attention has been given to the proximate factors
that influence movement patterns and foraging behavior within a species.
While movement patterns are often related to foraging, individuals also move
for other reasons. If females remain stationary and are patchily distributed
(as is the case in ambush foragers), breeding males may move more to
acquire mates than they would to forage. Such an increase in movement by
males could alter their growth, foraging patterns, diets, or at the very least,
skew estimates of their true foraging effort. In 2007, preliminary data
suggested that the ambush foraging lizard Sceloporus woodi showed a trend
towards sexual dimorphism in movement patterns during the late breeding
season and early post breeding seasons. The current study hypothesizes
that male and female S. woodi differ in both movement and foraging patterns
within the breeding season and between the breeding and post-breeding
seasons. This study summarizes a full year of focal observations on male
and female lizards from early breeding season to late post breeding season.
Standard movement variables (percent time moving and moves per minute)
will be presented and compared with additional metrics of foraging behavior
(e.g. rate of foraging attempts, attacks while stationary). Lag sequential
analysis will also be used to determine whether differences in movement
patterns correspond to differences in the manner in which prey is acquired.
P3.126A WILSON, R S*; NIEHAUS, A C; WHITE, J; RASMUSSEN, A;
KUCHEL, L; Univ. of Queensland; [email protected]
Using video documentary-making to enhance learning in large first year
Biology classes
Engaging Biology students in course material can be notoriously challenging
in large first year undergraduate classes. We trialed the use of video
documentary-making as a vehicle for enhancing the engagement and
participation of students in a first year Ecology course with 590 students.
Students were given the task of making a 5-7 minute documentary about a
topic of important local or national environmental significance and
communicating the science underlying the issue. Students worked in groups
of 4 students and were given access to a library of 50 Sony digital video
cameras and a large computer lab fitted with iMac computers. We found
students spent an order of magnitude more time on their video assignment
than their writing assignments of equal assessment weight. In addition, we
found students directly engaged with professional scientists during the
making of their videos and each group interviewed at least one scientist for
their documentary. This trial clearly emphasized the benefits of utilizing novel
technologies for motivating students across broad science and non-science
majors to take a greater interest in the natural sciences and explore the
science underlying environmental issues.
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P3.52 WILSON, M.P.*; SIMS, E.L.; SCHMITT, D.; DUKE UNIVERSITY;
[email protected]
Ankle flexion and foot clearance during flexed hip and knee walking
Modern humans walk with a relatively stiff gait that minimizes the muscular
work done to move the lower limbs and the center of mass. Nonhuman
primates, and perhaps our earliest ancestors, use a form of bipedalism in
which the hip and knee are held in a deeply flexed position and the center of
mass undergoes very little vertical oscillation. This study follows up on other
studies examining loading and energetic costs during these compliant
walking gaits by examining the effects of increased hip and knee flexion on
the dorsiflexion of the ankle and the toe clearance in adult humans. During a
flexed hip and flexed knee gait, our subjects demonstrated an average
increase in dorsiflexion of 16 degrees during stance phase and 13 degrees
during swing phase, as well as reduced toe clearance compared to a normal
walking style. Increased dorsiflexion requires more muscular effort to
stabilize the ankle during both stance and swing phase, and may explain
differences in distal tibia orientation and muscle markings on bones between
apes, early humans, and modern humans. The decreased foot clearance
during flexed hip and knee gait suggests that the changes at the hip, knee,
and ankle were still not enough to bring about the same foot clearance as
normal walking. This, in combination with the fact that our ancestors had
unusually long feet and particularly long toes, suggests that they would have
had to use other mechanisms such as toe flexion to clear the substrate.
These data provide novel insight into the nature and costs of locomotion in
bipedal primates and the earliest human ancestors.
P1.39 WINDSOR, P.J.*; LEYS, S.P.; Univ. of Alberta; [email protected]
Multipolar sponges: a putative role for Wnt signaling in the most basal
metazoans
The Wnt signaling pathways play important roles in multiple developmental
mechanisms: oral-aboral patterning in cnidarians, tissue differentiation and
cell migration in C. elegans, segment and limb polarity in Drosophila, and
body polarity and patterning in vertebrates. Lithium chloride has classically
been used in experimental embryology as a tool for understanding axial
specification in animals ranging from cnidarians to vertebrates. Treatment
with lithium mimics the Wnt signal, creating a constitutively active signal to
transcribe downstream targets such as Hox genes. As a result, normal
development of body polarity can be interrupted as seen in Hydra and
Xenopus. We sought to understand the role of the Wnt pathway in a sponge
using lithium treatment, as more familiar molecular tools such as RNAi are as
yet unavailable for these animals. High doses of lithium caused sponges to
lose essential traits in the normal functioning of a juvenile or adult individual,
including the canal system that is responsible for current intake and thus
feeding. Threshold doses of lithium produced sponges with a disorganized
canal system with multiple excurrent openings (oscula) in 95% of individuals
(n=21). Sponge polarity is determined mainly by the flow of water in and out
of its canal system, so having multiple oscula indicates a multiplication of the
main body axis. Wnt pathway components have only recently been identified
within the sponge genome and no functional studies have been carried out to
date. Future work will include further isolation and analysis of conserved Wnt
pathway components including frizzled, beta-catenin and gsk-3beta, as well
as attempting new methods for functional characterisation.
P1.78 WOLFF, S.W.*; ELY, T.E.; CHANTAROJWONG, T.M.; HELBING,
C.C.; PROPPER, C.R.; Northern Arizona University, University of Victoria;
[email protected]
Effects of 4-tert-octylphenol on amphibian metamorphosis
Many chemicals released into the environment impact physiological function.
These compounds are often referred to as endocrine disrupting compounds
(EDCs). Some EDCs impact thyroid function. Because metamorphosis in
amphibians is under direct regulation by thyroid hormone, this developmental
marker provides a strong endpoint for evaluation of a compounds potential to
disrupt thyroid hormone function. Estrogen exposure can impact thyroid
and/or thyroid hormone function. Octylphenol (OP), a common organic
pollutant found in wastewater effluent has estrogen-like actions. We looked
at effects of environmentally relevant levels of octylphenol on metamorphosis
in the amphibian model, Xenopus laevis. We exposed animals (90/treatment)
to control water, water containing 10-9 M estradiol as a positive control, and
three concentrations of octylphenol (10-7 M, 10-8M or 10-9M). We evaluated
timing of development and growth. We found no effects on developmental
stages or mass across any of the treatment groups, suggesting that neither
low levels of E2 nor OP impacts thyroid hormone- related development. Our
results demonstrate that exposure to OP at environmentally relevant levels
does not impact thyroid-mediated developmental measures. Future studies
will examine how OP impacts development of the gonads.
P3.119 WONG, G.K.*; CHABOT, C.C.; Quinnipiac University, Plymouth
State University; [email protected]
The Bioscience Education Network (BEN) Digital Library Portal and
Collaborative
The Internet provides ready access to a large volume of material that can be
used for teaching purposes. Digital libraries in particular offer a vast
repository of easily accessible resources for use by teachers at all audience
levels. However, in searching for specific learning items, it is often difficult to
separate the "wheat from the chaff" and find accurate and useful information
and techniques for the classroom or laboratory. In the biological sciences,
the Bioscience Education Network (BEN) portal provides easily searchable
access to digital libraries maintained by more than 25 different professional
organizations (including SICB). This peer-reviewed content includes images,
animations, and activities that have been tested in the laboratory or
classroom and been found to be effective in helping students to understand
important biological principles. While over 11,000 peer-reviewed resources
covering 77 biological sciences topics are available, the BEN portal allows
the user to easily narrow down the content using not only the typical search
attributes such as keywords or title, but also by discipline (subject),
pedagogical use, resource type, audience (education levels), author, or
author institution. Organization members of the BEN Collaborative also
accept materials for inclusion in the digital library through a peer-review
process. The BEN Collaborative was established in 1999 by the American
Association for the Advancement of Science (AAAS) with 11 other
professional societies and coalitions. In 2005, the BEN Collaborative was
selected as the National Science Digital Library (NSDL) Pathway for
Biological Sciences education. An overview of the BEN portal and its
advantages in preparing course materials will be illustrated in this poster
session.
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P2.142 WOO, H.*; WEIGAND, K.L.; DEAROLF, J.L.; Hendrix College,
Conway, AR; [email protected]
Development of the guinea pig (Cavia porcellus) diaphragm
Neonatal mammals, because of their increased metabolic rates, breathe
faster than their adult counterparts. For example, neonatal guinea pigs take
123 breaths per minute, a rate 40% higher than the adult ventilatory rate (87
breaths/minute). These increased breathing rates suggest that neonatal
ventilatory muscles have greater proportions of fast-twitch fibers than adult
muscles. But, to support neonatal breathing rates, the fast-twitch fibers also
need to have adult contractile abilities. To test these hypotheses, the
fiber-type profiles and myosin heavy chain (MHC) expression patterns of
neonatal and adult guinea pig diaphragms were determined. We expect that
the muscles of neonates will contain 40% more fast-twitch fibers than the
diaphragms of adults, based on the difference in their ventilatory rates. To
have adult contractile abilities, neonatal muscles will also express only adult
MHCs. Muscle samples were collected from 1-day-old neonatal and adult
(49- and 59-days gestation) guinea pigs and prepared for histochemistry or
SDS-polyacrylamide gel electrophoresis. The neonatal diaphragm contained
87.5% ( 0.67) fast-twitch fibers, approximately 40% more fast-twitch fibers
than found in the adult muscle (63.7% 2.5). These results support the
hypothesis that neonatal breathing muscles contain greater proportions of
fast-twitch fibers than adult muscles. They also fit our expectation for the
neonatal guinea pig diaphragm. Our findings suggest that the differences in
ventilatory rates between neonatal mammals and their adult counterparts
can be used to predict the fiber-type profiles of neonatal breathing muscles, if
the adult profile is known. Preliminary analyses of the myosin gels show only
adult MHCs being expressed in the neonatal diaphragms, indicating that
these muscles have adult contractile abilities.
P3.160 WOOD, K.J.*; ZERO, V.H.; RENN, S.C.P.; Reed College;
[email protected]
Plasticity of gender-biased behavior in the Julidochromis cichlid
Most monogamous cichlids exhibit gender-biased social and parental
behavior. Conventionally, males are larger and are more aggressive and
territorial than females, while females provide the majority of direct parental
care. This is the case in the African cichlid Julidochromis transcriptus.
However, in the closely related Julidochromis marlieri, females are larger and
the more aggressive sex. To determine the socio-environmental influences
on this gender-bias reversal, we experimentally manipulated the relative
sizes of monogamous pairs in both species. Then, using the freeware
program Jwatcher, aggressive behavior was quantified continuously during
10-minute observations using a universal ethogram for all species and
sexes. Aggression was measured both towards conspecifics on the other
side of a clear divider and towards heterospecifics introduced to the tank.
Males were found to be more aggressive overall in J.transcriptus, while
females were more aggressive in J.marlieri. However, size-reversed pairs of
both species were found to be behaviorally reversed in respect to
aggression: female J.transcriptus and male J.marlieri showed more
aggression than their mates. This work defines an interesting model with
which to address the molecular and hormonal basis of gender-roles and
gender-biased behavior. As cichlid fish enter the "post-genomic" era, it
becomes possible to address these questions on a genome wide basis.
P3.122 WOODLEY, S.K.; Duquesne University; [email protected]
Assessing Students Beliefs and Knowledge Regarding Animal
Research
Although much biomedical and physiological research involves animals or
animal tissues, the use of animals in the classroom is decreasing. Hence,
students pursuing careers in biomedical and physiological research may be
unprepared for the ethical and regulatory issues involved. Undergraduate
students knowledge and opinions regarding animal research were assessed
with a survey. Subjects consisted of students enrolled in a physiology course
and students enrolled in a required biology seminar. Both groups possessed
many common misconceptions about animal research. For example, none
understood the difference between animal rights and animal welfare and
most were unaware of the extensive animal research regulations. I argue
that it is important for biology teachers, especially physiology teachers, to
discuss these issues with students. I propose several teaching strategies that
can be used in physiology courses to educate students about animal
research. I also describe how the effectiveness of these tools can be
assessed.
P3.93 WOODS, K.M.*; DOWNER, A.N.; COWGILL, J.A.; GILLEN, C.M.;
HARTLAUB, B.A.; Kenyon College, Gambier, OH; [email protected]
Statistical modeling of real time PCR data for membrane transporter
expression in Manduca sexta larvae.
We examined the relationship between midgut transporter expression and
larval instar in the tobacco hawkmoth Manduca sexta, testing the hypothesis
that increased expression of midgut transporters compensates for reduced
surface area to volume ratio as larvae grow. We used real-time PCR to
investigate expression of two transporters: masBSC, a cation-chloride
cotransporter, and KAAT, a potassium amino acid cotransporter. masBSC
mRNA was detected in all tested tissues including foregut, midgut, hindgut,
salivary gland, and Malpighian tubule, with no significant differences in
expression level between tissues. KAAT mRNA was also detected in all
tested tissues with approximately 500 fold higher expression in middle and
posterior midgut than other tissues. Midgut expression of both genes was
increased by 2 to 9 fold in the fifth compared to fourth instar larvae. We
compared standard parametric methods (t tests and ANOVA procedures)
with Mann-Whitney-Wilcoxon and Kruskal-Wallis tests, competing
nonparametric procedures. With the exception of a few cases, the parametric
and nonparametric tests yielded similar test statistics resulting in no change
in significance. Ansari-Bradley tests showed no significant differences in the
variability between instars. Sensitivity analyses showed that outliers did not
have a significant effect on our inferences. For masBSC, multiple linear
regression models explained approximately 89 percent of the variability in Ct.
Similar models were fit and analyzed for KAAT, using Ct and delta Ct as
response variables. The multiple regression model for KAAT explains
approximately 96 percent of the variability in delta Ct, with significant instar,
tissue, and interaction effects. (This project was supported by Kenyon
College.)
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P1.99 WORTHAM, J.L.*; MCRAE, L.K; University of Tampa;
[email protected]
A Comparison of Grooming Behaviors in Smasher and Spearer Mantis
Shrimp
Grooming behaviors are frequent actions performed by crustaceans.
However, there is much variation in how many grooming appendages are
used and what body regions are cleaned. Mantis shrimp are marine benthic
crustaceans that groom their bodies, using one pair of grooming
appendages. Generally, mantis shrimp can be divided into two
morphologically and ecologically different groups, smashers and spearers.
Spearers are usually dull in color, have poorer vision, live in murky waters,
and are active at night. In contrast, smashers are normally bright in color,
have detailed vision, live in clear waters, and are active in the day. Both
groups live in a burrow, rather it be self-excavated in the sand or in a
pre-existing cavity in rock. Grooming behaviors, in terms of frequency, region
groomed, and length of groomed action, were observed in 17 different
species (15 smashers; 2 spearers) of mantis shrimp across 112 individuals.
Differences in areas groomed and grooming frequencies were compared
between species and sexes based on group, type of burrow, and time of day
they are active. Data analyses infers that 1) both groups groom their bodies
frequently, 2) regions of the body groomed vary between groups, and
3)grooming behaviors do vary between groups that live in different ecological
habitats.
P3.111 WOZNICA, S.A.*; ZHEN, Y.; HARTZELL, A.; RAGKOUSI, K.;
SWEENEY, S.; DAVIDSON, B.; University of Arizona;
[email protected]
Analysis of FGF/Ets target genes in the basal chordate Ciona
intestinalis
Fibroblast growth factor (FGF) signaling has a critical but poorly defined role
in vertebrate heart cell specification. We are exploiting the genetic and
cellular simplicity of the basal chordate Ciona intestinalis to explore the
precise function of FGF in heart development. We have found that FGF
signaling drives specification of the heart precursor cells through activation of
an Ets family transcription factor (Ets1/2). Microarray analysis of gene
expression from sorted heart lineage cells has led to the identification of
candidate FGF/Ets target genes. We are currently studying the regulation
and function of several candidate genes, including the transcription factors
GATA, ELK and Hand-like as well as potential signaling factors such as ASB
and Cyp26. Detailed analysis of the regulatory elements driving heart lineage
specific expression of these targets will delineate the precise impact of
FGF/Ets on the heart gene regulatory network. Functional analysis through
misexpression and antisense morpholino knock-down will determine the
specific roles of these genes in Ciona heart development. This research will
provide the basis for collaborative efforts focused on identification of novel
genes involved in vertebrate FGF signaling and cardiogenesis.
P3.198 WRIGHT, M.L.*; SWINSTROM, K.; CALDWELL, R.L.; Univ. of
California, Berkeley, Santa Rosa Junior College; [email protected]
A phylogenetic examination of social monogamy in stomatopod
crustaceans
The Lysiosquilloidea, a super-family of stomatopod crustaceans, includes
several socially monogamous genera, providing an unique system to study
the evolution of monogamy. Social monogamy is maintained by different
mechanisms within these genera. In the family Lysiosquillidae, energetic
costs of making burrows, predation risks, and spousal feeding behaviors all
likely contribute to the maintenance of monogamy. In contrast, selection for
biparental care maintains monogamy in some species in the
Nannosquillidae. Using comparative phylogenetic methods, I examined the
evolution of social monogamy in the Lysiosquilloidea. To test the monophyly
of the Lysiosquilloidea and provide more internal resolution of the clade for
future studies, I used the mitochondrial loci 16S and 12S, as well as a
morphological matrix (Ahyong 2000), to create phylogenies using maximum
parsimony and Bayesian tree-building methods. The monophyly of
Lyiosquilloidea was well-supported in the analyses. The internal branching of
the four families was consistent in both analyses, indicating that
Nannosquillidae and Tetrasquillidae are sister clades, and that
Lysiosquillidae is sister to all other Lysiosquilloidea. I then reconstructed the
evolution of social monogamy on the Bayesian tree (MK1) and the parsimony
trees (MP). Social monogamy has originated at least three times in
stomatopod crustaceans, suggesting that further phylogenetic comparative
studies on the correlations between monogamy, environment, and biparental
care in this group will be fruitful. The relationships between superfamilies, as
classified by Ahyong (2000, 2001), were not stable in this analysis and
should be re-examined using more characters, especially molecular and
genomic data.
P2.148 WU, Wen-Hui*; HILL, J; COOPER, Robin; university of KY;
[email protected]
Infuence of nicotine on physiology, development and behavior of
Drosophila melanogaster
The effects of nicotine (NIC) on physiology, development and behavior of
Drosophila were examined. The effects of nicotine, in a dose-dependent
manner, in relation to larval body wall and mouth hook movements were
quantified. Acute exposure to 0.1M reduced eating behavior substantial
within 10 minutes with less of a reduction at 0.01M with no significant effect
at 0.001M. Whereas a 24 Hr exposure showed some effects at all
concentrations but in a dose dependent manner. Body wall movements were
also substantially reduced at 0.1M with less of an effect at lower
concentrations. The death rate of larval from 1st instar to pupation was
enhanced in a dose-dependant manner 0.001M to 0.1M. In larvae, NIC also
enhances the CNS motor unit drive in segmental roots. This enhancement is
blocked by mecamylamine an antagonist to nicotinic receptors. We are
currently performing learning assays on larval and adult Drosophila that have
been exposed to various concentrations of nicotine and the nicotinic receptor
blockers. The results allow one to analyze how sensory perception is brought
about on the cellular and molecular level and the role of the nicotinic
receptors in this system. To assess the effects of nicotine directly on the
larval heart, the exposed heart was monitored without the CNS intact.
[Support: G. Ribble Fellowship in Biology at Univ. KY (JH)]
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P2.44 YAP, ANNA; VAN GURP, JAMES; MENON, JAISHRI*; William
Paterson University; [email protected]
Nitric oxide synthase isoforms in metamorphosis of anuran tadpoles,
Xenopus laevis
Nitric oxide (NO) a signaling molecule, produce in situ by nitric oxide
synthase regulate metamorphosis in some invertebrates as well as
ascidians. NO has both, apoptotic and antiapoptotic properties mediated via
activation of caspases and guanyl cyclase respectively. NO is also involved
in cellular dynamics of regressing tail of anuran tadpoles. The objectives of
the present study were to investigate a) cell specific localization for NOS
using immunohistochemistry (IHS) b) if thyroid hormones control gene
expression for NOS isoforms and c) changes in NO sensitive guanylyl
cyclase in intestine and tail during different stages of metamorphosis of
Xenopus laevis tadpoles. Immunostaining shows that, both NOS I and III are
expressed in cytoplasm of epithelium and brush border of the intestine just
before remodeling begins, and in epidermis of tail before regression begins.
Though, there was stronger expression for NOS I than NOS III in both the
tissues. NOS II was not expressed at all in either tissue. Increased apoptosis
during critical period of intestinal remodeling and tail regression is associated
with high expression of NOS I. RT-PCR results show that during
spontaneous metamorphosis, when endogenous T3 levels are at peak, (as
well as following exogenous T3 treatment) there is down regulation of NOSI
in intestine. However, in tail there is up regulation of NOS I at the same stage
(beginning of tail regression). Absence of guanylyl cyclase in either tissue
indicates lack of NO signaling via formation of cGMP, but it may be via
caspases favoring apoptosis. In conclusion, NOS(s) might be playing a
crucial role as an endogenous regulator of NO signaling in intestinal
remodeling and tail regression of anuran tadpoles promoting apoptosis in a
tissue and/or cell specific fashion.
P3.9 YATES, M.*; CARROLL, M.A.; CATAPANE, E.J.; Medgar Evers
College; [email protected]
Effects of Two Forms of EDTA, on Cadmium Accumulations in Gill of
the Eastern Oyster, Crassostrea virginica
Cadmium (Cd) is a trace metal with no known biological functions. In humans
it adversely affects a number of organs, including kidney, liver and lung by
inducing apoptotosis or carcinogenesis. Routes of exposure include cigarette
smoke and ingestion of cd contaminated food. Cd pollution is widespread in
the aquatic environment and marine animals, especially bivalves,
accumulate cd. The gill of the oyster Crassostrea virginica is a good tissue to
study cd accumulations. Previously, we showed p-aminosalicylic acid was
not effective in reducing cd accumulations. Sodium EDTA (EDTAna) was
moderately effective. In clinical setting, calcium EDTA is the preferred form
for metal chelation therapy. We sought to determine if there were a
difference in efficacy of the 2 forms of EDTA in reducing cd accumulations.
Gills were incubated for 10 hours with 500 µM cd then removed from the cd
and incubated with EDTA for 3 days. Cd levels were measured using
electrothermal vaporization with deuterium lamp background correction in a
Perkin Elmer AA800 Atomic Absorption spectrophotometer with a THGA
graphite furnace. Low concentrations of EDTAna (up to 1 mM) did not reduce
cd accumulations; however, the higher concentrations (2 mM) was
moderately effective in reducing the accumulations by about 40%. The
EDTAca was significantly more effective in reducing cd accumulations,
especially at low concentrations. A 2 mM concentration of EDTAca reduced
accumulation by 60%. Even lower concentrations (500 µM and 1mM)
produced significant reductions in cd accumulations, 25% and 40%,
respectively. Cd accumulations cause serious toxic effects in animals and it
can be valuable to find effective agents that can remove cd from tissues and
blood. This work was supported in part by grants 0516041071 of NYSDOE,
0622197 of the DUE Program of NSF and 0420359 of the MRI Program of
NSF.
P3.178 YI, S.Y.*; GORDON, N.M; WELCH, A.M.; University of Missouri,
College of Charleston; [email protected]
Sources of variation in female preference for long mating calls in gray
treefrogs (Hyla versicolor)
Theoretical models of sexual selection suggest that females with strong
preferences will mate with males with the most exaggerated traits, resulting
in offspring that carry the genes for extreme values of both trait and
preference. One consequence of these models is that daughters of more
attractive males should inherit genes for stronger preferences than daughters
of less attractive males. Alternatively, variation in preference strength may
result if females in better physical condition are better able to seek out an
attractive mate. Female gray treefrogs (Hyla versicolor) exhibit a clear
preference for mating calls of long duration, and there is variation among
females in the expression of this preference. In order to test the effects of
sire attractiveness and body condition on female preference in gray
treefrogs, we assessed the preference strength of lab-reared female
offspring of short and long-calling fathers. We manipulated the condition of
these females by placing them on either a high or low feeding treatment.
Female frogs were tested in an anechoic testing chamber using unequal
playback levels of synthetic mating calls. We defined preference strength as
the amount (dB SPL) that the intensity of a long call can be reduced relative
to the short call before the female prefers the shorter call. We found that
preference strength was not significantly affected by fathers call length, food
treatment, or body condition. Additionally, female response times showed no
relationship with either preference strength or condition. Hence, neither
genetic variation nor variation in condition appears to explain variation in
preference strength in gray treefrogs. It is possible that preference strength
depends on variables that we did not measure, such as age or past
experience.
P3.180 YOSHIDA, K*; KUROIWA, A; TERAI, Y; MIZOIRI, S; AIBARA, M;
KOBAYASHI, N; MATSUDA, Y; OKADA, N; Tokyo Inst. of Technology,
Yokohama, Hokkaido Univ., Sapporo; [email protected]
Chromosome evolution of the cichlid fishes from Lake Victoria
Lake Victoria in East Africa harbors more than 500 endemic cichlid species
that are morphologically and ecologically diverse. Geological evidence
suggests that the speciation event of the cichlids occurred in burst less than
15,000 years ago. This event is reflected by very low diversity of cichlid
genome sequences, reported by the molecular genetics studies. The cichlids
are studied as model system of speciation. Although studies of chromosome
evolution may provide insight into speciation of cichlids, the cytogenetics
study of the Lake Victoria cichlids has not been performed yet. Therefore, the
aim of this study was to analyze the diversity of karyotypes of Lake Victoria
cichlids in order to elucidate the relation between the chromosome evolution
and the speciation. The karyotype analysis indicates that the cichlids from
lakes Victoria and Malawi basically possess 44 chromosomes. Surprisingly,
a few additional chromosomes were found in Lake Victoria species. The
number of additional chromosomes is different among individuals. The
karyotype analysis of F1 showed that the additional chromosome inherited
by non-mendelian inheritance. These features suggest that the additional
chromosome was thought to be B chromosome that is non-functional
chromosome. B chromosomes have not been reported in African cichlids.
60% of the Lake Victoria cichlids possess two B chromosomes, 24%
possess one and 7% possess three. Strikingly, the morphology of B
chromosomes was various. This result suggests that B chromosomes
appeared in the origin of the Lake Victoria cichlids and evolved through the
process of the rapid speciation.
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P3.13 YOUSSEF, S. K.; FISCHER-DROWOS, S.; MORRIS, R. W. *;
VATNICK, I.; NAGENGAST, A. A; Widener University, Chester, PA;
[email protected]
The Effect of Perfluorooctane Sulfonate Exposure on Gene Expression
and WBC in Mouse
Perfluorooctane sulfonate (PFOS) and similar organofluorides have been
used in applications such as clothing, carpets and fast food containers by
companies such as 3M for over fifty years. PFOS bioaccumulates and
significant levels have been found in mammals, fish, and birds. In laboratory
studies, rats exposed to PFOS showed a dose-dependent decrease in
bodyweight, increase in corticosterone and norepinephrine, and a decrease
in reproductive ability. In humans, PFOS has a serum half-life of 8.5 years
and has been detected in people of all ages in many places around the
world. In vitro studies suggest PFOS exposure may have an
immunosuppressant effect. In order to explore the health effects of PFOS
exposure, we exposed twenty-five isogenic male mice to PFOS at 0mg/kg/d
(control), 3ng/kg/d (average human exposure), 1mg/kg/d, or 5mg/kg/d
(middle to high doses) in their drinking water for two months. Bodyweight and
eating/drinking habits were monitored throughout the exposure period. The
mice were sacrificed, blood was collected from the carotids, and organs were
harvested and frozen in liquid nitrogen for further analysis. White blood cell
counts in the 2 higher doses were 50% lower than the control and low dose
animals. These results suggest that PFOS has an immunosuppressant effect
and verifies previous in vitro studies. We are currently investigating gene
expression levels in the 3ng/kg/d and 5mg/kg/d group mice compared to
control mice by microarray analysis. Because factory workers in
PFOS-producing plants had a higher rate of bladder cancer, we are
extracting RNA from the bladders of control and exposed mice to probe
microarray chips containing 25,000 genes. We expect to find variation in
expression of genes associated with bladder cancer, particularly fgfr3, hras,
rb1, tP53, tsc1.
P2.21 YUAN, W*; WALTERS, LJ; HOFFMAN, EA; SCHNEIDER, KR; Univ,
of Central Florida; [email protected]
Limits on survival: examining salinity tolerance in the non-native
charru mussel, Mytella charruana
As a newly introduced species to the southeastern Atlantic coast of the
United States, the charru mussel Mytella charruana, has the potential to alter
shoreline ecosystems and out-compete native species. These mussels are of
concern because of increasing numbers, potential economic costs to power
plants, and displacement of commercially valuable native species. To
understand the potential salinity range that M. charruana can withstand, we
tested survivorship of mussels by increasing or decreasing the salinity in
laboratory conditions. Our goal was to determine survivorship when mussels
were exposed to salinity treatments ranging from 0 - 45 ppt (0, 2, 5, 14, 23,
31, 40, and 45 ppt) with salinity either being: 1) adjusted gradually over a
period of time or 2) shocked with no gradual adjustment to the target salinity.
There were 5 replicate tanks of each treatment and 15 mussels per tank.
Mortality in each tank was recorded daily for 43 days. Mytella charruana
showed greater survival in lower salinities (5 23 ppt) after being gradually
adjusted, indicating it is more likely to invade estuaries with significant
freshwater input. In examining the effects of these two salinity factors on
Mytella charruana, our hope is to gain a better understanding of the biology
and potential range of this non-native mussel.
P3.176 ZACK, T/I; CLAVERIE, T; PATEK, S/N*; Univ. of California, Berkeley;
[email protected]
Elastic energy storage and the mantis shrimps powerful predatory
strike
Storage of elastic energy is key to increasing the power output of jumping
and predatory strikes. One notable example is the energy stored prior to the
extremely rapid raptorial strikes in mantis shrimp (Stomatopoda). Several
structures have been proposed as the site of elastic energy storage,
including a leaf-spring shaped structure (meral-V) and a saddle-shaped
structure (saddle) located on the lateral and dorsal sides of the merus
segment of the raptorial appendage, respectively. The goals of this study
were to determine the location of elastic energy storage, characterize the
elastic behavior, and to examine the scaling of energy storage across a
range of body sizes. Using a materials testing apparatus, we directly
measured the force and work required to contract the elastic structures in 25
Gonodactylus falcatus individuals. We found that the force needed to
contract the appendage exhibits a positive and linear correlation with the
distance it has been contracted. Thus, this system can be modeled as a
simple Hookean spring with a spring constant of 58.3 N.mm-1 ( 10.6). The
overall force required to compress the spring is positively correlated with
body length and appendage size, but the spring constant is not correlated
with body size. The primary site of elastic energy storage is in the meral-V
rather than the saddle. However, removal of the saddle causes the system to
exhibit greater fatigue and dramatically increased the probability of failure. In
conclusion, the meral-V provides the elastic energy storage to power the
strike, and the saddle most likely confers dynamic stability. Uniformity of the
spring constant suggests that larger individuals simply compress a similar
spring over greater distances to power their larger appendages.
P2.196 ZANI, P.A.*; COUNIHAN, J.L.; FRIED, B.; SHERMA, J.; Lafayette
College; [email protected]
Effects of winter temperature on the energetics and hydration of lizards
Global climate change has the potential to increase winter temperatures,
resulting in higher winter metabolic rates of ectotherms, and thus, altering
energetic requirements for survival. To test the impacts of winter temperature
on survival of ectotherms, we subjected side-blotched lizards (Uta
stansburiana) to relatively warm (8 C) or cold (1 C) winter conditions for up to
149 d. As in previous experiments, animals in the cold survived longer than
those in warm winter conditions. As lizards died naturally we quantified
neutral lipids using HPTLC of the liver, fat body, and tail as well as carcass
moisture content. We also euthanized lizards as controls during the
experiment. Results indicate that animals that died naturally lost significantly
more mass than controls with a marginal temperature trend (warm treatment
lost more mass than cold). However, organ masses were not related to
temperature or type of death (natural/control). Furthermore, percentages of
triacylglycerol (TG) in fat bodies and tails were not different in animals
exposed to warm or cold temperature, but animals in the cold had higher
levels of liver TG than animals in the warm treatment. Thus, only liver TG
appears to be affected by winter temperature. Yet, there was no difference in
liver TG between natural death and control animals suggesting that lack of
TG was not the cause of death. When we compared moisture content of
animals we found that those exposed to a warm winter contained less water
at death than those exposed to the cold. Furthermore, animals that died
naturally contained significantly less moisture than controls. These results
suggest that the primary effects of winter temperature in these lizards are on
hydration rather than energetics and that water loss is the main cause of
winter mortality.
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P2.78 ZHUANG, K.*; ROTH, E.; FORTUNE, E.S.; COWAN, N.J.; Johns
Hopkins University; [email protected]
Linear Modeling of Tracking Behavior in Weakly Electric Fish
Weakly electric knifefish swim to maintain their relative position within a
moving refuge. Dynamical system models provide a language for describing
such systems. When applicable, linear dynamical systems models admit a
particularly powerful suite of analyses that facilitates the generation of novel
hypotheses. Here, we present a methodology for assessing the regimes for
which linear dynamical systems approximate experimentally measured
sensorimotor performance. Using this methodology, we tested the linearity
hypothesis for refuge tracking in several species of weakly electric knifefish
(Eigenmannia virescens, Apteronotus leptorhynchus, Apteronotus albifrons)
for refuge movements limited to approximately 2 Hz oscillation frequency and
15 cm/s maximum velocity. We measured the system output (fish position
and velocity) to an array of input signals (refuge trajectories), including pure
sinusoids, sums of sinusoids, and band-limited noise. Tools for data analysis
included ARMAX (autoregressive moving average with exogenous input)
modeling and coherence analysis. ARMAX modeling provided a way to
statistically quantify the linear dynamics of tracking responses using model
parameters. Coherence analysis, commonly used for characterizing neural
activity, provided a way to assess frequency regimes in which tracking
behavior was linear. The results were consistent with the linearity hypothesis
proposed in Cowan and Fortune (2007).
P1.87 ZIGLER, Kirk S.*; RAFF, Rudolf A.; BYRNE, Maria; RAFF, Elizabeth
C.; LESSIOS, H. A.; Sewanee: University of the South, Indiana University,
University of Sydney, Smithsonian Tropical Research Institute;
[email protected]
Gamete compatibility and genetic divergence between the echinoids
Pseudoboletia maculata and P. indiana
The echinoids Pseudoboletia maculata and P. indiana have overlapping
ranges on the east coast of Australia. We estimated their time since
divergence using mitochondrial DNA sequences, conducted controlled
crosses between the species, studied the molecular evolution of the sperm
protein bindin, examined their distribution in the field, and determined their
annual spawning period. We found that though the two species diverged
several million years ago, they cross-fertilize easily. Easy cross-fertilization
correlates with minimal divergence in the bindin gene between the species.
Individuals of the two species can be found within a meter of one another in
the field and their spawning periods overlap throughout the year.
P3.202 ZIMKUS, Breda, M.; Harvard University; [email protected]
A new species of Phrynobatrachus (Anura: Phrynobatrachidae)
endemic to Mount Oku, Cameroon, with discussion of puddle frog
biogeography across the Cameroon Volcanic Line
A new miniature species of puddle frog of the genus Phrynobatrachus
restricted to Mt. Oku in the Republic of Cameroon is diagnosed on the basis
of morphological characters and molecular data. Unlike all other miniature
Phrynobatrachus (snout-vent length < 20 mm), males of this species have
unique ventral coloration characterized by a black throat with a dark brown
belly, while the proximal portions of the forelimbs are cream in color. Minute
spines cover the venter in males, often appearing as white asperities. The
description of this new species supports the significance of this montane
ecoregion as a biodiversity hotspot for anurans. Patterns of species
divergence among eleven species of Phrynobatrachus from Cameroon were
analyzed using phylogenetic analyses of mitochondrial DNA sequence data
from 12S rRNA, valine-tRNA, and 16S rRNA. A clade endemic to the
mountains of Western Cameroon and Eastern Nigeria, part of the geologic
rift zone termed the Cameroon Volcanic Line, supports the view that
montane regions have acted as centers of speciation. Bioko Island
(Equatorial Guinea), located 32 km off the coast of Cameroon, is populated
by three different lowland Phrynobatrachus species from the mainland. Two
of these species reach submontane elevations on Bioko Island (up to
1200-1300 m) when compared to only lowland populations on mainland
Cameroon.
P3.197 ZIMMERMAN, L.M.*; PAITZ, R.T.; VOGEL, L.A.; BOWDEN, R.M.;
Illinois St. Univ.; [email protected]
Seasonal variation in innate and adaptive immunity of adult red-eared
sliders, Trachemys scripta
Previous studies on the reptile immune system have shown that aspects of
the innate and adaptive immune response exhibit seasonal variation that is
species specific. Sex may play a role in seasonal variation in red-eared slider
turtles Trachemys scripta, as male and females have different patterns of
resource allocation across the seasons. The purpose of this study was to
examine the effects of season on various branches of the immune system of
adult red-eared sliders. Blood samples were taken from male and female
turtles during the active season which occurs from late April until October. A
bactericidal assay that measures the killing capacity of plasma against
bacteria was used to measure innate immunity. A delayed type
hypersensitivity (DTH) reaction to phytohemagglutin (PHA) was used to
measure cell-mediated immunity. Total immunoglobulin levels will be
determined by ELISA as a measure of humoral immunity. Results indicate a
significant effect of season on both killing capacity and the DTH response.
Killing capacity peaked in late May and continued into early June before
dropping off dramatically in August and September. The DTH response
peaked in late May before dropping off to a consistent level for the remainder
of the active season. There was no significant correlation between an
individuals killing capacity and the DTH response. No significant effect of sex
on the killing capacity and the DTH response was found, therefore
differences in resource allocation between the sexes are most likely not
driving the observed seasonal variation in immune function. Our results
suggest that there is a complex relationship where the change in season
affects each branch of the immune system differently.
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P2.177 ZIMMERMANN, Emily *; DIONNE, Megan; FREDERICH, Markus;
YUND, Philip O.; U. of New England; [email protected]
Differential response of AMP activated protein kinase (AMPK) and
HSP70 to temperature stress in a gastropod
Nucella lapillus is a common gastropod in rocky intertidal habitats of the
North Atlantic. Populations are polymorphic for shell color, with light-colored
shells predominating on warmer, wave-protected shores and dark-colored
shells limited primarily to cooler, wave-exposed shores. Color morphs exhibit
differential heating during thermal stress, with darker shells attaining higher
body temperatures than lighter shells. These results suggest that heat stress
may determine field distribution patterns. However, there is currently little
evidence of physiological consequences of thermal stress in these
organisms. Following the guiding hypothesis that heat stress leads to cellular
energy depletion, we explored whether AMPK is activated by heat stress,
and compared this response in both color morphs to the expression of a heat
shock protein (Hsp70). Hsp70 is widely used as an indicator of thermal
stress, but it can also be induced by other stressors. AMPK is a central
energy regulator in mammals that activates ATP-generating catabolic
pathways and inactivates ATP-consuming anabolic pathways. Though AMPK
is highly conserved during evolution, it has rarely been studied in
invertebrates. Two color morphs of snails were tethered to a rock, exposed
to varying levels of heat stress (within the range known to occur regularly in
the field), and sampled at three time points. AMPK activity increased earlier
and at lower temperatures than HSP, and was higher in dark vs. light color
morphs. Furthermore, AMPK activity had decreased by the onset of HSP
expression. Our results suggest that AMPK may be an early indicator of
thermal stress in gastropods, and a useful tool for studying thermal stress in
the field.
P2.28 ZOU, Enmin; Nicholls State University, Thibodaux, LA;
[email protected]
Effects of hypoxia and sedimentary naphthalene on the activity of
N-acetyl-beta-glucosaminidase in the epidermis of the brown shrimp,
Penaeus aztecus
The brown shrimp, Penaeus aztecus, is subject to dual stresses of
environmental hypoxia and contamination of polycyclic aromatic
hydrocarbons (PAHs) in the northern Gulf of Mexico. The effects of hypoxia
and sedimentary naphthalene, administered alone and in combination, on
epidermal activity of N-acetyl-beta-glucosaminidase (NAG) were
investigated. It was found that hypoxia and sedimentary naphthalene, when
given together, significantly inhibited epidermal NAG activity. Since NAG
activity is a biomarker for ecdysteroid signaling in the epidermis, the
inhibitory effects of simultaneous exposure to hypoxia and sedimentary
naphthalene suggest that these two environmental stressors together can
have adverse effects on molting of the brown shrimp. The results of this
study also show that sedimentary naphthalene potentiates hypoxia effects on
epidermal NAG activity.