Download Hematodinium - University of Maryland Eastern Shore

Fimbriae
Nucleoid
Ribosomes
Plasma membrane
Bacterial
chromosome
Cell wall
Capsule
0.5 µm
(a) A typical
rod-shaped
bacterium
Flagella
(b) A thin section
through the
bacterium
Bacillus
coagulans (TEM)
Most bacteria isolated from the wild have one or more plasmids.
Most are cryptic (unknown function).
The Process of Bacterial Conjugation:
There are many examples of plasmids encoding determinants of
pathogenesis:
Examples:
Antibiotic resistance: Resistance Factors (R-factors) provide
the molecular explanation for clinically relevant antibiotic
resistance.
Multiple drug resistance can be carried on the same
plasmid (such as pBR322 which carries resistance to
both ampicillin and tetracycline)
Virulence genes:
a) Adherence factors
b) Lysis factors (ColE1)
c) Iron acquisition factors
Possesses adherence pili
Lacks adherence pili
http://www.palaeos.com/Kingdoms/Prokaryotes/Eubacteria.htm
Pathogenic Schemes of Diarrheagenic E. coli:
Bundle Forming Pilus
E. Coli adhering to intestinal cells
http://cmr.asm.org/cgi/content/full/11/1/142
Vibrio parahaemolyticus
http://www.mednet.cl/link.cgi/Medwave/Reuniones/
medicina/2006y2007/8/2544
http://www.bccdc.ca/dis-cond/a-z/_v/Vibrio/default.htm
 Gram negative bacterium
 Common cause of gastrointestinal illness from eating raw or undercooked shellfish
 Precise means of virulence still unknown
Pseudomonas marginalis:
 Gram – bacteria that causes soft rot
of plant tissues
 Present in soil and water of
Delmarva watershed
 Able to degrade phytate (a form
of phosphorous in chicken manure) to
a bioavailable form of phosphorous, contributing to algal blooms)
Cyanobacteria
The photosynthetic systems of cyanobacteria generate ATP,
NADPH, and O2
The ability to use water as an electron source is believed to have
generated the oxygen in the earth’s atmosphere
http://www.ucmp.berkeley.edu/bacteria/cyanointro.html
http://sun.menloschool.org/~nfortman/8th/webpages2001sp/blakes.precambrianEra/cells.html
14_44_Life_evolved.jpg
http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/Cyanobacteria.htm
In cyanobacteria, thylakoids are invaginations of the plasma
membrane :
Number - Responds to Light Intensity
Low light -> Many (to catch more light)
High Light -> Few (not as many needed)
Photosynthetic Electron Transport
During light excitation, electrons are moved to an “excited state”
The free energy as the electrons “fall” from their excited states is
used to make ATP and NADPH
http://www.jensenlab.caltech.edu/Projects/carboxyso
mes.gif
Carboxysomes:
Special complexes that contain
the enzyme RuBisCO
Carbon Fixation
The reaction below is catalyzed by the most abundant enzyme
on earth: ribulose bisphosphate carboxylase (Rubisco):
This reaction requires NADPH and ATP hydrolysis
The 1,3 diphosphoglycerate that is formed serves as the
substrate for the eventual synthesis of glucose in the cytosol
Photosynthesis Overview
 The overall reaction for photosynthesis can be
written as:
6CO2 + 6H2O + energy → C6H12O6 + 6O2
 During photosynthesis, electrons are
transferred from water to carbon dioxide, and
glucose is formed.
 Water has been oxidized; carbon dioxide has
been reduced.
Aerobic Respiration in Bacteria
Oxygen (O2)
necessary here
http://www.ucl.ac.uk/~ucbplrd/ETchain.png
Why do you think that photosynthesis must have evolved first?
The Current Theory of the Evolution of
the Eukaryotic Cell
• According to the endosymbiotic hypothesis, (advanced by
Lynn Margulis and also Sarah Gibbs), eukaryotes arose from
a symbiotic relationship between various prokaryotes.
- Heterotrophic bacteria became mitochondria.
(Heterotrophs are organisms that feed off of other
organisms)
- Cyanobacteria (phototrophic organisms- derive their
energy from sunlight) became chloroplasts.
- The original host cell is believed to have been a large
eukaryotic cell.
Internal membrane systems are the hallmark of eukaryotic cells
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
ArchaeBacteria bacteria
BACTERIA
ARCHAEA
Protista Plantae Fungi Animalia
EUKARYA
Protista: single celled eukaryotic organisms. Protozoa is often a synonymous term, although
this term usually does not include the photosynthetic protists (such as dinoflagellates and algae)
FOSSIL HISTORY OF ALGAE
Fossil Cyanobacterium
• Dates back to 3.5 billion years before present.
• First algae—Cyanobacteria—photosynthetic, without any
complex organization.
• Cells with complex organization evolved with nucleus and
other cellular organelles. With the exception of the
cyanobacteria, algae are eukaryotes—that is, the insides of
their cells are organized into separate membrane-wrapped
organelles, including a nucleus and mitochondria.
Green Algae
The single-celled algae Chlamydomonas
Volvox
Contain same chlorophyll a and b as in cyanobacteria
Reserve food in the form of starch
Cell wall made of cellulose
Gave rise to land plants
http://faculty.abe.ufl.edu/~chyn/age2062/lect/lect_15/22_15.GIF
Ulva lactuta: Sea Lettuce
http://www.chesapeakebay.net/fieldguide/critter/sea_lettuce
 Very common in nutrient rich areas
 Will often block light to sea grass beds
Red Algae: Gracilaria vermiculophylla
http://www.marinespecies.org/photogallery.php?album=766&pic=3539
U. lactuca and G. vermiculophylla together form 80% of the macroalgal biomass
in the Chesapeake Bay region (Thomsen 1998; Tyler et al. 2005).
Rhodophyta
 No flagella
 Food reserves of floridian starch (a type of pectin)
Chloroplasts only contain chlorophyll a, and also contains both
α and β Carotene.
 Cell wall associated with sulfated galactan
polymers that are economically important (ex: agar and
carrageenan)
Micro Algae
http://www.scctv.net/biomedia/pdf/BOmicrolife/Protists.pdf
 Algae are very diverse, but generally we can describe them as
a) Single celled protists that live in water environments
b) Usually carry out photosynthesis
c) Usually have a flagella and a cell wall made of cellulose (most)
and/or silica (dinoflagellates and diatoms )
 The most important photosynthesizing organisms on earth. They capture
more of the sun's energy and produce more oxygen than all plants combined
 Algae are extremely important in aquatic food chains ( a major
component of plankton).
 In the euglena shown above, the red eye spot serves as a guidance system
that allows cell to seek out maximal light conditions for photosynthesis
Chromista: Diatoms
http://botit.botany.wisc.edu/images/130/Protista_I/Diatom_Images
/Grouped_diatoms_MC_.html
http://www.bethel.edu/~kisrob/bio321/lab/BIO321AquaticAlgae/i
mages/Diatoms%2C-mixed.jpg
Interesting features of diatoms:
a) The photosynthetic pigment is yellow, not green (mix of
chlorophyll c and carotenoids)
b) Energy storage from photosynthesis in form of oil droplets
c) Cell walls consist of silica (basis of diatomaceous earth)
d) Comprise 20-25% of the world’s primary biological production
Alveolates: Dinoflagellates
 “Ancient” eukaryotic features:
Low level of histone proteins; a major component of the
DNA attached to membranes (as in bacteria)
 “Mixotrophic”: some species are mainly photosynthesizers,
(autotrophs) while others can phagocytose microscopic organisms
(heterotrophs)
Two dividing dinoflagellates
http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artsep01/dinof.html
Pyrrhophyta: Dinoflagellates
Two flagella inserted into their cell wall. One wraps around the cell
(transverse flagellum), while the other, longitudinal flagellum, extends
perpendicular to it. The beating of the longitudinal flagellum and the
transverse flagellum imparts a forward and spiralling swimming motion.
Both heterotrophic (eat other organisms), autotrophic (photosynthetic)
and mixotrophic dinoflagellates are known.
http://www.geo.ucalgary.ca/~macrae/palynology/dinoflagellates/theca.gif
In some countries, in summer or autumn months, massive
dinoflagellate blooms tint large areas of the sea surface a red or yellow
color. This phenomenon called 'red tides', is often caused by changes in
water temperature or light and associated with an abundance of
nutrients like nitrates and phosphates (eutrophication) carried into the
sea by coastal rivers.
Many kinds of marine life suffer, for the dinoflagellates produce a
neurotoxin which affects muscle function in susceptible organisms.
Humans may also be affected by eating fish or shellfish containing the
toxins.
A "red tide" off the coast
of La Jolla, California
http://en.wikipedia.org/wiki/Red_tide
Karlodinium Feeding on Rhodomonas
 Karlodinium associated with fish kills in the Chesapeake Bay region
 Secrete a toxin which paralyzes prey. When blooms occur, the toxin densities are high enough
to kill the fish
http://www.mdsg.umd.edu/CQ/v06n1/side3/index.php
Was There Another Fish Killer? The Case for a Toxic Culprit
Tracking sample after sample,
Allen Place turned up a toxic
dinoflagellate in his laboratory
that now shows up at fish kills
all along the Mid-Atlantic and
beyond. Photograph by Michael
W. Fincham.
 In August 1997 an algal bloom formed at the mouth of
the Pocomoke River, common in the nutrient-rich
waters of the Chesapeake Bay. Most likely this crowd of
algae contained what scientists call cryptophytes, a
major food source for algae eaters, like menhaden.
 When menhaden gathered to feed on the bloom,
Karlodinium veneficum also showed up. Not unusual.
For many feeding dinoflagellates, cryptophytes are a
favorite prey.
 As the menhaden fed on algae, these dinoflagellates
passed through their gills. The Karlo-toxin toxin began
to attack the gill tissue of the fish.
 Dead and dying fish drew dormant Pfiesteria out of
their cysts in the sediment and they began to feed on
this banquet of fish tissue.
Some are even parasites of marine species, such as crabs and lobsters:
Hematodinium perezi in
the lymph of the blue crab
http://www.vims.edu/~jeff/dinos.htm
http://www.ucmp.berkeley.edu/protista/dinoflagellata.html
Hematodinium sp.
 Infects numerous crustaceans in worldwide distribution
 Invades hemolymph of host; consumes hemocyanin and
mobilized host metabolites; combined lack of oxygen, nutrition, and
concurrent tissue damage; crustaceans become sluggish and with
heavy infections will die
Hematodinium sp. trophont form in blue crab hemolymph
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
ArchaeBacteria bacteria
BACTERIA
ARCHAEA
Protista Plantae Fungi Animalia
EUKARYA
Protista: single celled eukaryotic organisms. Protozoa is often a synonymous term, although
this term usually does not include the photosynthetic protists (such as dinoflagellates and algae)
http://www.arthursclipart.or
g/biologya/biology/classifica
tion%20animals.gif
A Generalized Mollusc
Whelk shells
Northern Quahog
http://www.cabrillo.edu/~jcarothers/lab/notes/molluscs/FRAMES/MainFrame.html
The Arthropods
http://static.howstuffworks.com/gi
f/adam/images/en/arthropodsbasic-features-picture.jpg
http://www.britannica.hk/zoology
/arthropod-355876.html
http://web.vims.edu/adv/ed/crab/guts20b.jpg
Eyestalk: hormone regulation
Rough map of the distribution of Carcinus
maenas, blue areas are the native range, red
areas are the introduced or invasive range,
black dots represent single sightings that did
not lead to invasion, and green areas are the
potential range of the species
http://en.wikipedia.org/wiki/Carcinus_maenas
 Feeds on bivalve molluscs (oysters, clams, mussels)
and small crustaceans
 Range is limited by the blue crab, which feeds on it
 The green crab has been hypothesized to have
brought Hematodinium disease to the eastern
coastal US
Range of Callinectes sapidus
 Cannibalized blue crabs make up as much as 13% of a crab's diet!
 Adult blue crabs prefer mollusks such as oysters and hard clams as their
primary food sources.
 Blue crabs are also scavengers of dead fish, shrimp, molluscs, etc;
After mating, females migrate to high-salinity waters in lower estuaries and near-shore
spawning areas. They over-winter before spawning by burrowing in the mud. Most females
spawn for the first time two to nine months after mating, usually from May through August
the following season. The female extrudes fertilized eggs into a cohesive mass, or "sponge,"
that remains attached to her abdomen until the larvae emerge.
http://www.bluecrab.info/spawning.html
 When ready to molt, the
crab "cracks" its shell
open from the back and
then backs out
 After shedding its old
shell, the crab first
expands its new shell by
pumping water into its
body. After that, it takes
about 72 hours (three
days) for the soft shell to
harden.
 The exoskeleton is made
of a material known as
chitin, which is a glucose
polymer with similarity
to cellulose
http://www.serc.si.edu/ed
ucation/resources/bluecra
b/molting.aspx
Proposed Life Cycle in the Blue Crab
http://www.americanscientist.org/templat
e/AssetDetail/assetid/37182/
page/2;jsessionid=aaa5LVF0#37425
How do blue crabs become infected?
a) Physical- Blue crab eats infected crabs or intermediate host
b) Dinospore- stage in water possibly encapsulated in a
sporocyst. Acquired through gills?
Dinospores Are Emitted from Diseased Crustaceans
Cancer pagurus
Motile cells observed following death
of a crab with Hematodinium.
Dr. Sue Marrs in Stentiford and Shields DAO,
2005, 66: 47-70
http://www.vims.edu/~jeff/biology/stentiford%20and%20shields%202005.pdf
Kim Jennings at IMET (Schott and Jagus lab) 2006
LMRCSC Internship
Hematodinium sp. Infection in Blue Crabs Has Seasonal Cycles
Messick and Shields 2000, Diseases of Aquatic Organisms
Goals of Our Lab
Very little is known about Hematodinium disease
transmission in nature
Find potential hotspots of Hematodinium in the Maryland Coastal
Bays (MCB)
a) Analyze its presence according to seasonal cycles
b) Uncover ecological variables that are associated with free-living
Hematodinium, and also discover potential alternate hosts
Procedures
Ponar Grab
YSI
20 micron plankton trawl
DNA Isolation kits
traditional PCR
QPCR
If I were to ask you the question: “what
do all living things share in common,”
what would you say?
The Nucleolus is the Site of rRNA Biogenesis
http://www.cytochemistry.net/cellbiology/nucleus3.htm
Alberts et al, Molecular Biology of
the Cell
rDNA is repetitive: multi-copy genes for ribosomal RNA (rRNA)
is present on 5 chromosome pairs
Great need in the cell for high levels of ribosomal synthesis
The nucleolus organizes around the rRNA genes
Depiction of The Ribosome as Seen by X-Ray Crystallography
NTS
SSU
ITS1
LSU
5.8S
NTS
ITS2
ITS1
TCGCACGAAGAAAATAATAATATATTTTATTATTTTCGCACACAAACATTCACCGTGAACCTTAGCCATTAGCTAC
GACGACTACTAGCTAGCTACTGAGTGGGGCGGTGGTGTGTTGGTTACTACTGCTACTTCTTACTCGTAGCTGA
ACTGCACACACACTAGTACCCCTCTCTTGCTGGTAGGAGAAGTAGCTTCTACGGGGTGTGAGGGTACGGTGG
TAGTACACGCCTACCACTGAACTCCTCCATCCCACGTTTGCTTTCCATAAACACAACATCTCTAATTTCAGCTAT
TCATCTTGCTCTGCTCCCTTTCGCGGGGATAGGGCTTTCTTCAAACGTATGAC
5.8S
TAGAAAATTTTAGCGATGAATGCCTCGGCTCGGGTTACGATGAAGGACGCAGCGAATTGCGATAAGCAATGCG
AATTGCAGAATTCCGTGAATCATCAGATTTTTGAACGTACTCTACGCTCTCGGGTATCCCTGGGAGCATGTCTG
GTCTCAGC
ITS2
GTCTGTTCAACCTTTTGTGCCTCCTGGAGTTGTGAACATTCTCCTTCTTGGAAGCGATTTTGTGCACCAGTGA
GCCTCTTTCCACACACATGCTCTACGACGCCTTGTTGTTGTAGACAGCGGAAGATGGCCATTGACGCATTAAA
TATTAAGGGATTTGTAGAATGTTGTAGAGAGGGTTGGTTGCGTACGTCTCACCGTACGCACCAAAAGCTCTGC
ATGTTCCCCAACAACACTTATGACCCACTTTAGGTCTAATGCTTGTTGGCCGAAGGGTTACACTGCATGGTTAT
ACCGCTACTCTTCTTCCGCCCTTTACCGTGATAGTACACAGGTTTTCGGACTAGTGGCGCTATTGCAGCAGAA
ATATTTATATCTCTGTATATATTTACACATG
NTS
SSU
ITS1
LSU
5.8S
ITS2
NTS
Peptide bond formation is catalyzed
by an enzymatic activity present in
the large subunit
The ribosome translocates, making
available a new A site
Elongating protein
(Most human proteins
are in the range of
100-2,000 amino
acids)
Comparison of two 18S Ribosomal RNA Sequences from
Hematodinium sp. and Humans
Endpoint PCR Analysis for Environmental Detection
Site 1
Site 2
Site 3
Site 4
Site 5
Site 6
Site 7
Site 8
Site 9
Commercial Harbor
Verrazano Bridge
Newport Bay
Trappe Creek
Public Landing
Whittington Point
Taylor's Landing
Wildcat Point
Greenbackville
Site 10
Site 11
Site 13
Site 14
Site 15
Site 18
Sinnickson
Chincoteague Channel
Tom's Cove
Johnson's Bay
Cedar Island
Snug Harbor
*
Water Collection Dates
7_10
9_10
6_10; 9_10
4/10; 7/10
6_10; 9_10
*4/10; 6/10; 7/10
*
*
6_10
4_10; 6_10; 7_10; 8_10;
10_10
7_10
6_11
4_10; 6_10
7_10
10_10
Sediment Collection Dates
8_11
4_10; 5_10; 7_10; 8_11
6_10; 8_11
8_11
5_10; 8_11
8_10; 8_11
8_10; 8_11
8_11
5_10; 7_10; 8_10; 10_10; 11_10
8_10; 10_10; 8_11
4_10; 6_10
 48 of 546 (8.8%) of environmental samples from the Maryland and Virginia coastal
bays were positive for Hematodinium sp.
 Four sites had detectable signal in water in April: earliest detection date we are
aware of.
Analysis of Hematodinium sp. at Sinnickson, Through
Clone Libraries Analysis of Dinoflagellate 18 S rRNA
Hematodinium Other species
April
15/16
1 unidentified nanoflagellate
June
2/13
July/August
13/25
10 Heterocapsa rotundata, 1 Peridinium sp.
3 Gymnodinium sanguineum, 1 Gymnodinium sp., 3 H. rotundata
October
1
10/16
and 5 unidentified dinoflagellates
2 Pentapharsodinium tyrrhenicum, 1 G. simplex, 1 Gymnodinium sp.,
1 H. rotundata and 1 Dinophyceae sp.
Hematodinium
Other species
April
15/16
1 unidentified nanoflagellate
June
2/13
July/August
13/25
10 Heterocapsa rotundata, 1 Peridinium sp.
3 Gymnodinium sanguineum, 1 Gymnodinium sp., 3 H. rotundata
October
10/16
and 5 unidentified dinoflagellates
2 Pentapharsodinium tyrrhenicum, 1 G. simplex, 1 Gymnodinium sp.,
1 H. rotundata and 1 Dinophyceae sp.
Hematodinium sp. “Hotpsots”
2010
April
2011
Water
Sediment
Trappe Creek
Taylors Landing
Sinnickson
Johnson’s Bay
Verrazano Bridge
Snug Harbor
May
Sediment
Verrazano Bridge
Public Landing
Sinnickson
June
Newport Bay
Public Landing
Taylors Landing
Greenbackville
Johnson’s Bay
July
Commercial Harbor
Verrazano Bridge
Trappe Creek
Sinnickson
Taylor’s Landing
Chincoteague Channel
Cedar Island
August
Newport Bay
Snug Harbor
Whittington Point
Wildcat Point
Sinnickson
Tom’s Cove
Sept.
Verrazano Bridge
Newport Bay
Public Landing
Oct.
Sinnickson
Snug Harbor
Nov.
Water
Sinnickson
Tom’s Cove
Tom’s Cove
Commercial Harbor
Verrazano Bridge
Newport Bay
Trappe Creek
Public Landing
Tom’s Cove
Whittington Point
Wildcat Point
Greenbackville
The MCB is a marine
system some input
from local rivers, but
not enough fresh water
to alter its high salinity
http://www.epa.gov/owow_keep/estuaries/
pivot/images/maps_no_points/2008mcbays
_no_points.jpg
http://www.mdcoastalbays.org/files/pdfs_pdf/Report_Card.pdf
“hotspots” all correlate with higher
clay % soils
Figure Courtesy Darlene Wells (MD-DNR)
and Roman Jessien (MCBP)
Averages for 2010 and 2011 in the MCBs
Chl
*
*
*
Newport Bay-3
Chl
(ug/L)
8.2
8.8
20.02
22.7
25.9
(ug/L)
3.9
17.1
9.4
15.3
16.8
9.4
14.7
8.7
8.3
April
May
June
July
Aug.
Sept.
Oct.
Nov.
9.5
13
18.7
39.6
28
4.2
18
23.8
27.3
27.1
8.1
9.5
8.7
April
May
June
July
Aug.
Sept.
Oct.
Nov.
7.2
19.4
23.1
24.4
15.4
2.2
9.2
9.7
4.5
9.3
6
19.2
4
3.6
April
May
June
July
Aug.
Sept.
Oct.
Nov.
5.4
9.8
23.4
21.7
28.3
4.9
8.9
8.1
11.5
14.6
6.2
12.8
3.3
4.5
April
May
June
July
Aug.
Sept.
Oct.
Nov.
6.8
Trappe Creek-4
*
NA
12.3
10.5
Public Landing-5
5.8
Taylor's Landing-7
2.7
The Normal Nitrogen Cycle in Water (A)
In marine communities the main
fixers of N2 are cyanobacteria
http://wordsinmocean.files.wordpress.com/2012/02/n-cycle.png
The Normal Nitrogen Cycle in Water (B)
Nitrobacter also can “fix” carbon, but they do it by chemosynthesis
using the energy from the oxidized nitrite.
http://acvaristica.files.wordpress.com/2008/07/nitrogen-cycle1.jpg
Nitrate Assimilation by Algae
http://www.jochemnet.de/fiu/bot4404/Nr_biochem_kl.jpg
In marine environments, nitrogen is usually the limiting nutrient. Thus, any additional
input will result in a strong enhancement of growth of the organisms that are there.
The Chesapeake Bay
Watershed
The Chesapeake Bay is an
estuary system with higher
salinities closer to the mouth
of the bay.
http://alldownstream.wordpress.com
/category/agriculture/
http://www.emporia.edu/earthsci/student/moran6/report1.htm
Septic systems in growing communities
are a greater threat to the health of the
MCB because sewage treatment plants
remove nitrogen more efficiently
http://extension.umd.edu/environment/water/files/septic.html
Rainfall runoff from impervious surfaces presents another problem, as these
surfaces are not as good at filtering nutrients and preventing excess nutrient
flow into local rivers
http://www.bing.com/images/search?q=AGRICULTURAL+RUNOFF+DELMARVA&view=det
ail&id=E880D7EC7FA60F205E88F31CD17F833188023BD4&first=0&FORM=IDFRIR
http://faculty.salisbury.edu/~mllewis/agriculture/conclusion.htm
DNA
ATP
Amino Acids
http://www.star.nesdis.noaa.gov/star/images/bestof2005/fig1.jpg
An algae bloom called a mahogany tide in
Spa Creek, a tributary of the Chesapeake
Bay. (Photo by Chesapeake Bay Program).
http://www.ens-newswire.com/ens/sep2010/2010-09-27092.html
The algae bloom in the Chesapeake Bay by the start of the Hampton
Roads Bridge Tunnel in Norfolk was taken on Tuesday, Aug. 18, 2009.
(Ryan C. Henriksen | The Virginian-Pilot)
http://hamptonroads.com/node/520146
Algal blooms can
block light
Seagrass beds will thus
be negatively impacted,
because they need to photosynthesize.
Seagrass beds are primary nurseries for immature
blue crabs
http://ens-newswire.com/ens/jul2004/2004-07-30-10.asp
Animal Manure Fouling Chesapeake Bay
By J.R. Pegg
WASHINGTON, DC, July 30, 2004 (ENS) - Cattle, pigs and chickens within the
Chesapeake Bay watershed produce some 44 million tons of manure each year and far
too much of it is seeping into the Bay, according to a new report by the Chesapeake Bay
Foundation. The report says this pollution must be reined in if efforts to restore the
health of the Bay are to succeed.
"The Chesapeake Bay is being choked by excess manure, and despite years of effort the
Bay's water quality is not improving," said CBF President William Baker. "Action to stop
the pollution must begin now, not next year or several years from now."
There is broad agreement that the Chesapeake Bay is an ecosystem in serious peril, and
despite a slew of agreements and goals to protect and restore the Bay, little has
changed in past decade. The nation's largest estuary continues to suffer from an
unnatural influx of nitrogen and phosphorous, which come from sewage wastewater,
agricultural runoff, urban runoff and air pollution. These pollutants feed massive algae
blooms that kill fish and Bay grasses, which provide vital habitat for the Bay's famous
blue crabs. Robbing the water of oxygen, these algae blooms can form massive dead
zones - last year a dead zone covered 40 percent of the Chesapeake's main stem and
stretched 150 miles.
Oxygen (O2)
necessary here
http://www.ucl.ac.uk/~ucbplrd/ETchain.png
Aerobic Respiration in Bacteria
In response to episodic hypoxia blue crabs will:
a) Try to swim away to areas of higher concentration
b) Reduce metabolic activities
In response to chronic hypoxia, not much is precisely known
a) They increase the concentration of hemocyanin, which is an
Oxygen carrying molecule in their hemolymph
b) They seem to be more susceptible to disease
 Blue crabs undergoing hypoxic stress are less capable of clearing Vibrio
infections than those under normoxic conditions
 It is likely that impaired hemocyte activity is the cause for this reduced
immune response
(hemocytes are the equivalent of white blood cells in crab hemolymph)
Recombinant DNA Technology:
The Cloning of Genes
The process of cloning involves several steps:
a) First, you have to identify what it is you want to clone;
For simplicity, we will start with a gene.
b) We then will use restriction enzymes to specifically digest
DNA that surrounds our gene of interest
c) Link these DNA fragments to a vector (usually a laboratory
plasmid that will enable us to propagate our clone
d) Next we transform the vector containing our cloned gene into
a host organism (usually E. coli). This enables us to make
multiple copies of the cloned gene.
A) Gene of interest
B) Digest vector and target
DNA with same enzyme
C) DNA ligase joins DNA
D) Transform plasmid into
E. coli
E) Cloned gene