Download Department of Biology and Earth Science Senior Research Symposium April 15, 2015

Department of Biology and Earth Science
Senior Research Symposium
April 15, 2015
ABSTRACTS OF SENIOR RESEARCH PROJECTS
(In Alphabetical Order)
Abena F. Agyepong
The Examination of Bacteria and Triclosan Resistance in Big Walnut Creek
Triclosan is a prevalent antibacterial compound that is found primarily in products
such as soaps, dental care, cosmetics, deodorant, and other personal care
products. However, triclosan is one of the most widely used biocides and it
displays a cross-resistance to other antibiotics. Not only does triclosan pose a
risk to humans, it is also a ubiquitous pollutant that is detected at high
concentrations in all types of environments such as aquatic environments and
soils. Because triclosan is so commonly used in a variety of products, it is fully
retained in wastewater treatment plants. It then makes its entrance into the
environment either through treated or effluent wastewater, raw influent directly
discharged by sewage overflows or absorption to sludge or biosolids. Generally,
high levels of triclosan have been shown in wastewater treatment plant influents
in the United States, Europe, and Asia. The aim of this project is to determine the
percentage of triclosan resistant bacteria present in Big Walnut Creek and
determine the biodiversity of the resistant bacteria. According to data that was
collected in duplicate at Big Walnut, 65.10% of bacteria were resistant. This
number was the highest out of all of the sites that were observed. Polymerase
Chain Reaction was used to amplify the 16S ribosomal RNA gene and products
were verified by gel electrophoresis. Metagenomic data showed the biodiversity
of all of the bacteria in Big Walnut Creek. The next step is sequencing the
triclosan resistant bacteria in order to determine their biodiversity as well as
reveal new species that may be present in Big Walnut Creek.
Bridget N. Bickers
Characterization of Suspected Cyclic di-GMP Metabolizing Genes in
Streptomyces scabies
Streptomyces scabies is a bacterial plant pathogen responsible for a condition
known as common scab in potatoes and other tuber crops. Aerial hyphae and
spore development have been shown to be regulated by cyclic di-GMP (c-diGMP) signaling in the non-pathogenic species Streptomyces coelicolor and
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Streptomyces venezuelae. The second messenger c-di-GMP is ubiquitous
among bacteria and is connected to many functions such as: motility, virulence,
and biofilm formation, but the effects of c-di-GMP signaling in other
streptomycetes are unknown. The purpose of this study is to elucidate the
function of the suspected S. scabies c-di-GMP phosphodiesterase genes
SCAB11501 and SCAB27241 through the construction of deletion mutants. The
effects these genes have on morphology, development, and virulence are of
particular interest in this study. Successful S. scabies deletion mutants for
SCAB27241 have been evaluated macro- and microscopically for differences in
morphology between the mutants and wild type. Potato infection assays were
performed in order to compare the mutant’s pathogenicity to that of the wild type.
These phosphodiesterase genes may represent targets for antimicrobial agents
that combat S. scabies infection and that of other related, prevalent agricultural
pests.
Sarah A. Bousfiha
HIV Co-infection: Syphilis and Hepatitis C
Background: Despite the progress made in antiretroviral medications for AIDS
prevention and early HIV infection, challenges are still present in cases of HIV
co-infection with other diseases, including syphilis and hepatitis C. Reasons of
HIV-syphilis and HIV-hepatitis co-infection were studied, as well as how coinfection causes diagnoses and treatment to be difficult in these cases. The
purpose of this literature review is to address questions regarding co-infection,
focusing specifically on HIV with neurosyphilis, and HIV with hepatitis C.
Methods: Internet databases and peer reviewed journal articles were utilized to
gather information on co-infection, based on year of publication and relevancy to
the topic. Results: Rates of syphilis are increasing in the United States, and HIV
co-infection is more common in cases of neurosyphilis. Hepatitis C cases have
decreased in the United States, however no vaccine is yet available to treat the
virus, and can lead to chronic infection. HIV-syphilis co-infection occurs largely
due to unprotected sex with infected individuals, and is highly represented in the
MSM population. HIV-hepatitis C co-infection is unlikely due to sexual activity,
and occurs in risk factor populations including intravenous drug users and
individuals receiving blood transfusion. Diagnosis in co-infection in general is due
to asymptomatic presence of infection, as well as similar symptoms among
different diseases and errors in testing. In both HIV-syphilis co-infection and HIVhepatitis C co-infection, treatment plans must take into account the stage and
progression of infection. Conclusion: Early diagnosis in both HIV-syphilis and
HIV-hepatitis C cases is of extreme importance, and the presence of HIV may
cause diagnosis and treatment to be rather conflicting. Individuals categorized
into risk factors for infection should be routinely tested and provided information
on sexually transmitted diseases. Efforts to provide available screening for
patients should be implemented in order to decrease rates of disease.
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Michael G. Brovarenko
Side Effects of Androgenic Anabolic Steroid Abuse in Athletes
Androgenic anabolic steroids (AAS) can cause a variety of side effects when
abused by athletes. Despite their reputation as harmful substances, AAS were
first developed for the beneficial purpose of increasing skeletal muscle mass and
to increase development of male sex characteristics. Additionally, AAS can be
clinically applied in the treatment of HIV-related muscle wasting, serious burn
injuries, post-surgical trauma, neuromuscular disorders, malnutrition due to
alcoholic cirrhosis of the liver, Duchenne's or Becker's muscular dystrophy, and
age-related muscle loss (Turillazzi E, et al. 2011). Professional athletes such as
Lance Armstrong have admitted to using AAS, claiming that it is impossible to
win events in professional sports without using steroids. Steroid abuse is a good
topic to perform a literature review on because it has been an issue in sports for
many years. This literature review was conducted to learn the state of knowledge
about the negative effects of AAS. Information was gathered by collecting articles
though the EBSCO search database on the website of the Courtright Memorial
Library at Otterbein University. From the 40 peer-reviewed research articles
obtained, 20 peer-reviewed articles were selected to include in this literature
review. Risk factors for AAS abuse are teenage preoccupation with body image,
being a male weightlifter with a poor childhood relationship with their father, and
having conduct disorder (Pope Jr. H, et al. 2012). Most fatal instances of AAS
abuse are caused by cardiac events such as heart attacks, coronary diseases,
and ventricular arrhythmias (Achar S, et al. 2010). Less common side effects
seen in long term- high dose AAS abusers are liver tumors -- typically in people
suffering from other liver diseases (Hardt A, et al. 2012). The conclusion of this
literature review is that steroids can cause psychiatric disorders, shutdown of
vital organs in addition to the heart, withdrawal symptoms, and even sudden
death. Recent studies of AAS use suggest that AAS abuse is as harmful today as
in 1975 when scientific data on AAS use was first collected.
Rebecca A. Carter
Winter Road Salt Incursions on Alum Creek and its Watershed Analysis
Road salt is a concern for many states in the northern United States. During
winter storms, road salt is applied to roads in conjunction with plowing. Extended
periods of below freezing weather usually results in significant salt volumes being
applied to roads, and with limited melting, the salt accumulates. When snowmelt
occurs, it generates run-off which dissolves the salt and transports it to both
surface and groundwater. Studies show that water quality, aquatic organisms,
and terrestrial organisms are adversely affected by the excess salt. Previous
research on groundwater, and to a lesser extent surface water, uses chlorine and
bromine ratios to identify the source of road salt from the mineral halite. This
study focuses in on identifying the potential source of elevated dissolved solids in
Alum Creek in Westerville Ohio following snowmelt events. Samples of Alum
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Creek water were collected by the Westerville Water Treatment Plant personnel
from the raw water stream following snowmelt events with elevated TDS
concentrations. The samples were analyzed by a commercial laboratory for EPA
methods 200.7 for sodium, iron, and calcium and 300.0 for chlorine and bromine.
Chloride and bromide ratios after snowmelt ranged from 311.36 to 16166, and
averaged 4095 through the 2014 and 2015 winters. Normalized readings for the
summer of 2014 were between 0 and 817.50. Results of this study show
inconsistent chlorine and bromine ratios due to the low concentrations in surface
water but sodium and chlorine concentrations are consistent with halite sources.
Although salt may not be the only factor behind the higher TDS reading, areas of
extensive development, farming, and natural salt formations can contribute. A
map of the Alum Creek watershed determined areas of high run-off potential that
contribute road salt into Alum Creek.
Leigh A. K. Dardio
Cyanotoxins and their Significance to Humans
Cyanobacteria are bloom-forming microorganisms commonly known as “bluegreen algae.” These species are widely dispersed and adapted to even very
extreme environments. They are especially significant to humans due to their
ability to produce a number of cyanotoxins which potentially pose serious health
effects for humans and aquatic ecosystems. This review aims to cover the
general knowledge of the effects of three common types of cyanotoxins
(microcystin, cylindrospermopsin, and anatoxin-a), the effects of these in
humans, factors stimulating the proliferation of cyanobacterial producers, and
future conditions most likely to encourage the continued dispersal of these
species. A recent case of substantial cyanobacterial bloom formation and
cyanotoxin production in Ohio is also examined as an example of an ecosystem
which is highly promotional of these activities.
Brianna N. Diehl
Improving Outcomes and Reducing Relapse for Patients Undergoing
Allogeneic Stem Cell Transplants
This literature review explores clinical trials concerning allogeneic stem cell
transplants. The variables included in this review are different HLA match
situations/graft procedures, and different conditioning regimens such as
combination drug therapies, TBI, and T-cell depletion. Efficacy and viability of
these variables are measured by statistical analysis for reduced relapse, lowering
the incidence of GVHD/OIs, and positive outcomes such as survival rates. Both
strengths and weaknesses in research studies, as well as areas of the literature
that can be expanded upon are analyzed in detail. For each patient with a given
set of risk factors (including age, severity of disease, and level of remission
achieved before transplantation) there is a near perfect regimen and transplant
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option available. Yet, the overwhelming issue is the lack of conducive research
supporting any one regimen for any one type of patient. In this review, a number
of current and relevant graft manipulations and conditioning regimens are
discussed. A wide gap exists between the large number of research done on
combination drug/TBI regimens and the small amount focused on manipulating
the actual stem cell graft. The most potential for increasing outcomes and
reducing relapse for patients with hematological diseases is by researching more
specific techniques of HLA-typing and finding new ways to adapt grafts at the
molecular level.
Joel N. Donahue
Characterization of a Putative Cyclic di-GMP Gene in Streptomyces
coelicolor
Streptomyces coelicolor is a Gram-positive, non-pathogenic bacterium that is
important in the production of antibiotics. SCO5511 is a gene that encodes an
EAL and GGDEF domain protein in this organism. EAL and GGDEF domains are
associated with phosphodiesterase activity and cyclic di-GMP production,
respectively. Cyclic di-GMP is a second messenger that is associated with
virulence, motility, and biofilm formation in a variety of bacteria. Preliminary data
from our lab shows that SCO5511 influences development in S. coelicolor. Data
accumulated in the bioinformatics portion of the project compares orthologous
genes from other Streptomyces species to that of S. coelicolor SCO5511 and
provides evidence that this protein has diguanylate cyclase activity, producing
cyclic di-GMP. Data obtained through attachment assays shows that the
SCO5511 mutant produces effective surface-attached communities of bacteria
called biofilms, as would be expected for a diguanylate cyclase mutant.
Bailey K. Dye
Toxicity of Leaf Extract of Acer Spp. on Equine Erythrocytes
Red maple toxicosis is a phenomenon that occurs in equines after the
consumption of dried or wilted red maple (Acer rubrum L.) leaves. Within the
erythrocytes, it causes hemolysis, methemoglobinemia, and Heinz body
development. The toxic agent of red maple leaves has not yet been identified;
however, the development of hemolytic anemia and methemoglobinemia in
equines after ingestion of the leaves, suggests that the toxin is acting as a strong
oxidant. Some studies have noted that not only are wilted red maples leaves
toxic to equines, but that wilted leaves of other maple species may also be toxic.
Therefore, the objective of this research was to evaluate the toxic effects of dried
samples of A. rubrum, as well as thirteen other species within the genus Acer, on
the hemolysis of equine erythrocytes. Two-year old saplings were evaluated in
greenhouse and field experiments of 5 and 3 replicates, respectively. Leaves
were harvested and dried throughout two growing seasons. The leaf material
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was suspended in water (0.05 g material/500 μl water) and incubated with equine
blood taken from the horses housed at the Austin E. Knowlton Equine Center for
two and three hours in 1.5 ml microfuge tubes for determination of percentage
hemolysis and percentage methemoglobin, respectively. Relative toxicities of
species were determined spectrophotometrically based on percentage hemolysis
of erythrocytes and percentage methemoglobin formation. Acer species differed
significantly for hemolysis and methmoglobin production. In the greenhouse
replications, the red×silver hybrid maple exhibited the largest amount of
hemolysis (2 to 3 times that of the control), as well as a high level of
methemoglobin formation (~69%). In contrast, Norway maple caused little
hemolysis and methemoglobin. The results of this study show toxicity to equine
erythrocytes may occur in multiple species throughout the Acer genus, indicating
that the toxic component may be an ancestral trait that has been lost in some
taxa.
Jared B. Ellenbogen
Recovery Potential of the Mussel Communities in the Lower Section of Big
Walnut Creek
Since the enactment of the 1977 Clean Water Act, biologists have created
numerous multimetric assessment tools to evaluate the biological integrity of
water resources, using biological criteria. The integrity of Big Walnut Creek, Ohio,
has been in flux since the 1955 construction of Hoover Dam, and while current
water quality is high, mussel communities in the creek have yet to recover to
historical levels. This study sought to determine the cause of the decline in the
mussels in the lower section of the creek below the dam. Historical creek data,
including a fish-based index of biotic integrity
(f-IBI), invertebrate community index (ICI), qualitative habitat evaluation index
(QHEI) and modified index of well-being (MIWB), were compared to a recent
mussel-IBI for the creek. These data were compared to urbanization data (i.e.
percent plant cover) describing land use in 1 km2 sample regions around each
biometric data collection site. Data were analyzed using linear region and student
t-tests to understand any correlative relationships with the status of mussel
communities. Mussel-IBI data were compared to percent land developed
(r2=0.225, p>0.01), percent plant cover (r2=0.1 p>0.01), road density (r2=0.007,
p>0.01), census tract data as a measure of population density (r2=0.003,
p>0.01), riparian zone width (r2=0.107, p>0.01) and creek width (r2=0.001,
p>0.01). Ohio EPA biometric data were compared to percent plant cover data: fIBI (r2=0.185, p>0.01), MIWB (r2=0.004, p>0.01), ICI (r2=0.028, p>0.01) and
QHEI (r2=0.265, p>0.01). No significant correlations were found between
urbanization and integrity, suggesting that land use does not directly affect the
lower section of Big Walnut Creek. Therefore, it is possible (pending future
research) that the mussel communities could recover in time, similar to the fish
and invertebrate communities in the creek.
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Conor G. Holland
Does Food Availability Influence Metabolic Rate?
Animals show developmental plasticity in response to various environmental
changes. We observed physiological and morphological responses when
Xenopus laevis tadpoles were exposed to low, medium, and high food levels.
We hypothesized that tadpoles from low food treatments would downregulate
metabolic rate, increase intestine length, and have smaller livers in comparison
to tadpoles from higher food treatments. We raised tadpoles at 150, 300, and
600 mg per week of Sera Micron until tadpoles reach 3.2-3.5cm in length.
Tadpoles were fasted for 24 hours and their metabolic rate was measured by
recording changes in oxygen by Witrox respirometry equipment. When
controlling for body mass and length, tadpoles raised in low food tanks had lower
metabolic rates than tadpoles reared at medium and high food levels. There was
no significant difference in intestine length and we were unable to detect
differences in liver size. The changes in energy allocation show that Xenopus
tadpoles respond to food shortage by down regulating their metabolic rate. We
were unable to definitively identify the mechanism for this response, but
differences in liver size could play a role. Other mechanism that should be
examined include fat body reserves, heart mass, muscle mass, and the number
of mitochondria.
Zebulon I. Martin
Are Threespot Damselfish Helping or Hurting the Possible Resurgence of
Acropora Corals?
There is a growing concern about decreased global biodiversity in general and
especially the decline of frame building acroporid species of Caribbean coral
reefs. This study examines a possible refugia for Acropora cervicornis coral in
the back-reef area of Ambergris Caye, Belize commonly referred to as Coral
Gardens. Our goal was to understand the carbonate budget and ecosystem
dynamics of this successful reef with emphasis on the role of herbivorous
damselfish and urchins. Benthic survey data from photo-quadrats along six
transects was supplemented with counts of urchins in various size classes. The
number and species of damselfish and a count of damselfish chimney scars was
also collected. The data indicates a positive correlation between the density of
Stegastes planifrons and the abundance of urchins suggesting that damselfish
do not reduce the number of urchins in their territories as previously reported.
The impact of damselfish on coral growth was quantified by counting chimney
scars in each quadrat. Scars occurred primarily in clumps and these were
concentrated on the edges of the patch reefs. Scarring did not correlate with
damselfish abundance. Our findings suggest that Threespot Damselfish probably
have little positive impact on the carbonate budget via the removal of scraping
urchins, but may potentially negatively impact coral growth, particularly at the
edges of the patches. This negative impact is probably minimal in large healthy
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patches, such as those examined in this study, but may be more significant in the
fragmented and isolated colonies that are now the norm in the Caribbean.
Kristen R. McCann
A Review of Current Research on Acer rubrum and Equine Red Maple Leaf
Toxicosis
Red maple leaf toxicosis is a debilitating syndrome caused by ingestion of red
maple leaves (Acer rubrum) by equine species. It was first reported in the
literature in the early 1980's. Red maple leaf toxicosis is characterized by the
weakening of the erythrocyte cell walls and by changes in the hemoglobin which
alter the oxygen affinity. This can result in the death of 60 to 65% of the horses
that ingest 1.5 g of dried leaves per kg body weight. Currently, the identity of the
toxin is unknown but some researchers hypothesize that the oxidant pyrogallol is
involved in the process of erythrocyte damage. This review of red maple toxicosis
will explore and discuss the nature of the toxin, as well as current procedures of
diagnosis and prevention of the syndrome. Specifically, the potential role of
antioxidants vitamin C and E in prevention and remediation will be addressed.
Rebecca R. McGinnis
Do Geriatric Hip Fracture Patients Admitted to an Orthopedic Specialty
Hospital Fare Better than those Admitted to a General Hospital?
The choice of hospital is a very important decision to make especially when there
is a major surgery occurring. Quality of care and success rates vary across
hospitals and the consumer should be informed before they undergo surgery. Hip
replacement is done for many reasons including osteoarthritis and fracture. Total
hip replacement surgery has become very common practice in every hospital. A
statistical analysis of surgery outcomes was taken between Crystal Clinic
Orthopedic Center and Akron City Hospital and allows for a more educated
reformation of surgical procedure between the two hospitals. There was a
statistically significant difference ( p value < 0.05) shown on two-tailed T test for
4 of the 5 outcomes studied (CCOC n=534 and ACH n=142): 30 day mortality,
physical therapy time, time until surgery, and operation time. In all of these
outcomes, Crystal Clinic Orthopedic Center performed better than Akron City
Hospital. The fifth outcome studied, in house death, showed no significant
difference between the two hospitals. Confounding the results is the fact that
there was also a statistically significant difference between the average ages of
the patients at the two hospitals, with the patients operated on at Akron City
Hospital being significantly older than those operated on at CCOC. Pairwise
tests were then run to account for the age and sample size differences. In the
pairwise tests, operating time, time to operating room and average physical
therapy all still showed a statistically significant difference. This study shows that
there is a difference between the attention to the patient provided at the two
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hospitals, but care must be used when generalizing the results due to both the
different sample sizes and average patient ages at the two hospitals studied.
Brice A. Mitchell
Trans-species transmission and zoonotic potential of Chronic Wasting
Disease
Chronic wasting disease (CWD) is a form of prion disease that affects members
of the North American cervid population, including white-tailed deer (Odocoileus
virginianus), Rocky Mountain elk (Cervus elaphus nelsoni), and moose (Alces
alces shirasi). After the link was discovered between bovine spongiform
encephalopathy (BSE) in cattle and variant Creutzfeld-Jakob disease (vCJD) in
humans through exposure to BSE-contaminated meat, the transmission of CWD
has been increasingly studied. In lab settings, variants of CWD have been able to
cross the species barrier and infect various species of North American rodents,
domestic cats, and primates. The susceptibility of primates to CWD infection has
caused concern for the potential of zoonotic spread. While there are no
confirmed cases of the cervidized prion disease causing disease in humans,
assessment of the possibility of CWD crossing the species barrier is of major
importance as exposure to the infectious prion through both consumption of
venison and interaction with areas of contamination have been on the rise within
the past decade. This literature review investigates the potential of chronic
wasting disease to cross the cervid-human species barrier and become zoonotic.
Samantha L. Perry
The stability of individual vocal signatures over time in adult male
budgerigars Melopsittacus undulatus
Individual recognition is when an animal associates a single individual with its
specific characteristics and markers, allowing them to monitor and improve social
interactions. Individual recognition can occur acoustically, this allows animals to
identify an individual and information about them from the individual signatures
within their vocalizations. Vocal learning is an animals’ ability to change its
vocalizations based on exposure and perception of sounds they hear.
Budgerigars are open-ended vocal learners, which means that they are capable
of altering vocalizations and learning new calls throughout their life. The objective
of this project was to determine if individual signatures within different call types
are stable over time. We also determined if altering social setting effects stability
of the parameters we analyzed.
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Ellen A. Proctor
Communication’s Influence on Social Bonds Formed by Chimpanzees
Communication plays a significant role in developing and maintaining strong
social bonds within conspecific groups in nonhuman primates. Within
chimpanzees, Pan troglodytes, individuals develop relationships to acquire
adaptive benefits including high social status, grooming, stress reduction, and
reproduction. Previous research has shown that aggressive and affiliative
behavior has had the most significant influence on building and maintaining
social bonds formed by chimpanzees. Individuals utilize forms of mutual
exchange, like interchange or reciprocity, in order to build social relationships.
Similarly, studies show that both gestural and verbal communication also play
roles in forming social relationships. This is due to chimpanzees often initiating
social interactions by using pant hoot calls or pointing and gaze orientation,
which lead to everyday behavioral interactions and therefore the formation of
bonds. This literature review further investigates the influences that various forms
of communication have on the development of social bonds within chimpanzee
groups.
Paige L. Regrut
A Review of the Costs of Caudal Autotomy and Factors that Influence the
Rate of Tail Regeneration
Caudal autotomy is the voluntary release of an organism’s tail to escape
predation. The release of the tail surprises the predator, causing the predator to
drop the organism during an attack. Caudal autotomy is used by amphibians,
(salamanders), reptiles (lizards) and mammals (mice). This literature review will
explore caudal autotomy, the organisms who use caudal autotomy, its survival
and reproductive costs, the factors that influence the frequency of caudal
autotomy and the rate of tail regeneration. Survival costs include increased risk
of predation, decreased growth rate and decreased locomotive speeds.
Reproductive costs include smaller clutch sizes because fat reserves are lost
when the tail is dropped. The rate of tail regeneration and the ability of the
organism to escape predation is influenced by the intensity and efficiency of
predators, conspecific crowding, and the number of successful attacks by a
predator. The efficiency of the predators in an area decreases the success of
caudal autotomy; an area with low efficiency predators has high success rates of
caudal autotomy. The intensity of predation can increase the frequency of tail
autotomy and decrease the rate of tail regeneration.
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Madeline A. Rohl
The Effect of Red Maple Leaf Toxicosis on Reduced Glutathione Levels in
Equine Erythrocytes In Vitro
Red maple leaf toxicosis is an equine blood disorder resulting from the
consumption of wilted red maple (Acer rubrum L.) leaves by horses. Compounds
within the leaves of red maple have oxidative effects on equine erythrocytes and
can cause hemolysis of erythrocytes, the conversion of hemoglobin to
methemoglobin, and the production of Heinz bodies. Reduced glutathione is
important in the protection of equine erythrocytes from these oxidative events;
however, in the presence of red maple toxin, glutathione is rapidly oxidized and is
unavailable. The objective this study is to determine whether the presence of
vitamin C alters levels of reduced glutathione for equine erythrocytes in vitro.
Equine erythrocytes were sampled and treated with red maple leaf extract alone
and in combination with vitamin C. Erythrocyte suspensions were then
measured for concentration of reduced glutathione with the use of
spectrophotometry. The results show a difference between reduced glutathione
levels in control blood samples and blood samples treated with extract from
wilted red maple leaves. Limited data shows an effect of vitamin C on samples
with and without red maple leaf extract. These results are supported by other
studies where oxidative damage in erythrocytes of other species causes
decreased reduced glutathione concentration.
Kristen H. Schmid
The Effect of MHC Diversity on Mate Choice in Captive African Penguins
(Spheniscus demersus)
Background: The major histocompatibility complex (MHC) is highly polymorphic,
functioning to maintain a proper immune system within all vertebrates. High
diversity within exon 2 of the MHC class II gene has been linked to increases in
both parasite resistance and overall fitness. Organisms mate with individuals who
will provide them with a high diversity of MHC class II alleles. The role MHC
diversity plays in mating of African penguins (Spheniscus demersus) has recently
been a topic of debate due to their endangered species status. The purpose of
this study is to determine the effects of MHC class II diversity on female mate
choice within a captive population of African penguins at Mystic Aquarium.
Methods: DNA was extracted from penguin blood samples. Exon 2 of the MHC
class II gene was amplified through PCR. The results were run on a DGGE, as
well as sequenced. The sequences were analyzed to determine individual MHC
alleles and compare the allelic combinations within the population. The MHC
alleles of mating pairs and parent-offspring relationships were analyzed.
Results: Of the twenty-eight penguins sampled, nine were homozygous, while
nineteen were heterozygous. Three alleles were identified within this population,
Spde001, Spde002, and Spde003. The allelic combinations produced four
genotypes: nine Spde001/Spde001, three Spde001/Spde002, eleven
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Spde001/Spde003, and five Spde002/Spde003. A lineage map connecting
mating pairs and offspring was constructed from the genotypes. Discussion:
The Mystic Aquarium population showed reasonable amounts of diversity based
on frequency of heterozygotes and patterns of mate choice. Heterozygosity with
regard to MHC was more common than homozygosity and presumably would
result in greater fitness. Through mating pair analysis, it was concluded that
eight of the females chose male mates that were dissimilar from themselves,
while one female chose an MHC similar male mate. The result of this dissimilar
mating is that African penguins are producing heterozygous offspring. MHCmediated mate choice is a tactic used by many organisms to ensure increased
fitness for their offspring, and it appears as though African penguins utilize this
method as well. Despite levels of heterozygosity and dissimilar mate choice, the
distribution of genotypic frequencies were no different than what would be
expected in Hardy-Weinberg equilibrium (X2df=5 = 8.7, P=0.12) (i.e., random
mating).
Amanda M. Stilwell
Manipulation of Same Sex Social Pair Bonds in Budgerigars, Melopsittacus
undulatus
Same sex pair bonding can be found throughout various animal species. These
relationships can be common in monogamous species, especially when there is
a lack of members of the opposite sex. Budgerigars, Melopsittacus undulatus,
are a socially monogamous species, which create strong pair bonds but are also
known to engage in extra pair copulations. When looking at an all-male flock of
budgerigars, the question arises, are these bonds easily broken or disrupted by a
third party individual. After determining seven pair bonds in a flock of 32 males,
these pairs were removed from an aviary and placed in separate lab cages
where their social structure was manipulated using a third party male or female.
Pairs were also categorized as strong, weak and control. Behaviors of affiliation
and aggression were recorded before, during and after a third party individual
was added and removed. It was found that there were no significant differences
in the behaviors performed between strong pairs when the third party individual
was present and after its removal. There were found to be significant differences
in the behaviors between pairs during the presence and after the removal of the
third party individual for weak and non-bonded pairs. It was concluded then that
strong pairs were not disrupted by third party individuals regardless of the third
party’s sex.
Michael J. Swenor
Decellularization of Liver and re-cellularization using Stem Cells
In the United States there are 24,383 people waiting for organ transplants. Of
these, 15,318 are waiting for liver transplants. While donor programs do
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wonderful things by helping find suitable organs for recipients there are still many
problems. One of the many problems of organ procurement is the fear of
rejection. Other problems include getting the organ to the point of transplant and
matching the recipient and donor with a viable organ. Most of the organs that are
donated will go to research and of the ones that are transplanted the chances of
rejection are high. The broader objective of this study was to find a better solution
to donor organ procurement. If we can successfully decellularize an organ or
multiple organs leaving behind the organ’s structure and then re-implant cells
from a person in need of transplant we could eliminate the need for donors. The
organs that we used were chicken livers and the stem cells that we plan to use
are derived from human urine. The idea behind using stem cells from urine is that
it would be a non invasive way to obtain stem cells. With successful recellularization we would expect the need of a lifetime of drug treatment for a
transplant patient to be eliminated as well. With the use of certain detergents,
such as sodium dodecyl sulfate, and phosphate buffered solution can literally
“wash” the organ of its cells leaving behind the extracellular matrix. Testing of the
tissues with a hematoxylin and eosin staining procedure we will be able to
determine if the washing the livers of all of their cells was a success.
Emily R. Willmer
A Comparison of the Genetic Diversity of the Class II Major
Histocompatibility Complex in ex situ and in situ Populations of African
Penguins (Spheniscus demersus)
As an endangered species, the African penguin (Spheniscus demersus) is at risk
of becoming extinct in the wild due to destruction of their coastal habitat and
reduction in food availability. The development of a genetically diverse and
healthy captive population is important in helping to conserve the species. The
goal of this project was to determine the genetic diversity of the class II major
histocompatibility complex (MHC) of a wild population of African penguins and
compare it to the diversity of the captive population at Mystic aquarium in Mystic,
Connecticut that has previously been studied. We found that the wild population
of African penguins that was sampled had similar levels of heterozygosity to the
captive Mystic Aquarium penguins but the number of alleles found in the wild
population was twice that of the captive population. Two undescribed alleles
were also found in the wild population. These results have important implications
in future management of this species as they indicate that practices need to be
put into place to enhance the genetic variability of our captive populations to help
ensure conservation of the species.
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