11th ICRS Abstract book - Nova Southeastern University

8.218
Bacterial Communities Associated With The Surface Mucopolysaccharide Layer
And Tissues Of Healthy And Diseased Montastrea Faveolata
Wes JOHNSON* 1 , Reney HENDERSON 2 , Garriet SMITH 3 , Ernesto WEIL 4 , Karen
NELSON 5 , Pamela MORRIS 1,6
1 Marine Biomedicine and Environmental Sciences Center, Medical University of South
Carolina, Charleston, SC, 2 Department of Biology, Howard University, Washington, DC,
3 Department of Biology and Geology, University of South Carolina Aiken, Aiken, SC,
4 Department of Marine Sciences, University of Puerto Rico Mayaguez, Mayaguez,
Puerto Rico, 5 The J. Craig Venter Institute, Rockville, MD, 6 Department of Cell Biology
and Anatomy, Medical University of South Carolina, Charleston
Corals naturally form associations with complex assemblages of microorganisms that are
thought to play vital roles in coral ecology. Detailed exploration of the composition and
structure of these communities can improve our understanding of the potential roles of
these communities and their interactions with their host. Our objectives were to (1) assess
the composition of the bacterial communities associated with Montastrea faveolata, (2)
compare the communities of healthy and diseased colonies of M. faveolata, and (3)
characterize the assemblages from the surface mucopolysaccharide layer (SML) and coral
tissue. Samples were collected from La Parguera, Puerto Rico in March 2006. SML and
tissues were collected from three healthy and three diseased colonies. Community DNA
was isolated and clone libraries of 16S rDNA genes were constructed by amplifying
nearly complete 16S rDNA sequences and inserting them into cloning vectors. Clones
were sequenced at the J. Craig Venter Institute (Rockville, MD). Comparisons of
community structure were also performed using denaturing gradient gel electrophoresis
(DGGE). Results from clone libraries showed tissues were dominated by
sphingobacteria, while SML communities were composed mostly of α-proteobacteria.
Diseased tissues had fewer Clostridium sequences than did healthy tissues. SML samples
also showed differences between healthy and diseased colonies, with healthy colonies
containing numerous sequences of Lactococcus lactis, which were not observed in
diseased samples. DGGE showed differences between SML communities of healthy and
diseased colonies that were not observed between healthy and diseased tissues. These
data indicate shifts in the structure of M. faveolata bacterial assemblages related to host
health, and suggests that SML and tissue communities are affected differently in diseased
corals. We are currently generating and sequencing metagenomic libraries to further
elucidate the composition and functional potential within these communities.
8.219
Role Of The Coral Surface Microbiota in Disease: An in Situ Test Using The
Gorgonia-Aspergillus Pathosystem
Emily BRODERICK* 1 , Karen BUSHAW-NEWTON 1 , Walker TIMME 1 , Jessica
WARD 2 , Kiho KIM 1
1 Biology, American University, Washington, DC, 2 Scripps Institution of Oceanography,
San Diego, CA
Surface mucopolysaccharide layer (SML) of corals are known to have a variety of
functions including serving as a protective layer against UV light damage and
desiccation. The SML is also an energy rich environment that supports host-specific
microbial communities. Studies have shown that the microbial communities shift, in both
richness and abundance, in response to environmental perturbations and pathogens. Thus,
analogous to the role of human gut microbiota, the coral surface microbiota may play a
mutualistic role in the health of the coral host. Indeed, the “coral-microbiota-disease”
hypothesis predicts that the coral surface microbiota is an important aspect of disease
resistance. More specifically, perturbation of the surface microbiota increases disease
susceptibility. Here, we report on in situ experiments to test whether the structure of the
coral surface microbiota is mutable in the Caribbean sea fan, Gorgonia ventalina. We
tested the effects of light reduction, nutrient enrichment, antibiotic wash, and pathogen
(Aspergillus sydowii) exposure on the microbiota as characterized using DGGE. Results
so far indicate that the structure of coral surface microbiota is mutable and that some
bacterial stains were present in untreated control corals and remained throughout all
treatments. In addition to the on-going work to characterize the structure of the
microbiota, it is also important to understand how an intact microbiota confers disease
resistance.
Poster Mini-Symposium 8: Coral Microbial Interactions
8.220
Discoloration Of Coral Larval Cultures Caused By Pseudomonas Sp.?
Iliana BAUMS* 1
1 Biology, The Pennsylvania State University, University Park, PA
Rearing of coral larvae from mass-spawning events is a common and important approach to
coral research and conservation. Yet, larval rearing in captivity is often associated with high
mortality rates. Larval cultures of the Caribbean mass-spawners, Acropora, Montastraea and
Agaricia predictably crash after two to three days. This crash appears associated with the break
down of unfertilized eggs. A pink discoloration of Montastraea faveolata larvae as well as of
tygon tubing and other plastic ware used for culturing was observed during multiple years and
at two locations. Brown (1974) described a similar phenomenon in embryos of bivalve
mollusks and identified antibiotic sensitive Pseudomonas sp. as the likely origin. It is
hypothesized that a related bacterial strain causes infections in coral larval cultures. Disinfection
of culture equipment with a 10% bleach solution prevented a spread in 2007, however delivery
of antibiotics sometimes promotes pink discoloration. Thus, the hypothesized target is an
antiobiotic resistant strain of Pseudomonas sp. Initial sequencing of a bacterial 16s RNA library
extracted from pink gametes yielded diverse sequences related to Bacteroidetes, Clostridium
and Vibrio but did not produce a Pseudomonas relative. Sequencing efforts are ongoing.
Meanwhile, simple disinfection procedures may alleviate problems with bacterial infections in
coral culturing efforts.
8.221
Patterns Of Antibiotic Resistance in Microbial Isolates From Pseudopterogorgia
Americana
Katherine WILLIAMS* 1,2 , Maria VIZCAINO 1,2 , Jennifer DELANEY 3,4 , Garriet SMITH 5 ,
Karen NELSON 6 , Pamela MORRIS 1,2
1 Marine Biology and Environmental Science, Medical University of South Carolina,
Charleston, SC, 2 Hollings Marine Laboratory, Charleston, 3 Hollings Marine Laboratory,
Charleston, SC, 4 Grice Marine Laboratory, The College of Charleston, Charleston, 5 Biology
and Geology, University of South Carolina - Aiken, Aiken, SC, 6 J Craig Venter Institute,
Rockville, MD
The coral surface mucopolysaccharide layer (SML) is home to myriad microbial species that
compete for habitat and nutrients, produce and resist anti-microbial compounds, and likely play
a role in coral health. This study examined differences in patterns of antibiotic resistance and
susceptibility profiles exhibited by bacteria isolated from healthy and diseased colonies of
Pseudopterogorgia americana. Mucus samples were taken from healthy and diseased colonies
off of the southern coast of Puerto Rico in March 2006. SML was spread-plated onto glycerolartificial
seawater (GASW) agar plates and incubated, and colonies were purified by successive
streaking. Isolates from one healthy and one diseased P. americana colony were resuspended in
GASW, introduced into 96-well plates containing 26 different antibiotics, and incubated
overnight. Resistance was indicated by greater than 20% of control turbidity at the minimal
inhibitory concentration (MIC) of antibiotic. The percentage of instances of resistance out of the
total number of possible instances (number of antibiotics multiplied by number of isolates) was
47% in the healthy-coral subset and 25% in diseased; of the four drugs which inhibited growth
in all of the isolates, three were cell wall synthesis-inhibiting antibiotics. These results suggest
that the microbial community of the healthy coral may be more stable than that of the diseased,
and reflects changes in both microbial community structure and the chemical ecology in these
communities.
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