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11th ICRS Abstract book - Nova Southeastern University

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7.195<br />

How Quickly Does gorgonia Ventalina Mount A Cellular Response To Elicitors?<br />

Courtney COUCH* 1 , C. Drew HARVELL 1 , Esther PETERS 2 , Laura MYDLARZ 3<br />

1 Department of Ecology and Evolutionary Biology, Cornell <strong>University</strong>, Ithaca, NY,<br />

2 Tetra Tech, Inc., Fairfax, VA, 3 Department of Biology, <strong>University</strong> of Texas at Arlington,<br />

Arlington, TX<br />

In fighting infectious microorganisms, corals rely on innate immune defenses. One of<br />

these primary defenses is the wandering phagocytic cells called granular amoebocytes.<br />

The Caribbean sea fan coral, Gorgonia ventalina, is a tractable system to study this<br />

cellular response because granular amoebocytes aggregate during exposure to the fungal<br />

pathogen Aspergillus sydowii and thermal stress, and can be quantified. In the lab, live A.<br />

sydowii was a successful elicitor of amoebocyte aggregation and revealed a time course<br />

peaking at 48 hours. After 48 hours, the response also showed a relaxation period<br />

between 72 to 168 hours. However, the induction of a coral cellular response in a field<br />

setting is still unclear. Therefore, a number of alternatives to live A. sydowii were tested<br />

to effectively stimulate an amoebocyte response in the field. In addition, field<br />

experiments are planned to examine the magnitude and time course of this cellular<br />

response in nature. Finally, one important unanswered question is: What is the coral’s<br />

cellular threshold to disease? Therefore, field experiments are planned to measure<br />

amoebocyte levels in sea fans exposed to multiple inductions overtime. Consequently,<br />

this research could provide valuable information towards the study of host-pathogen<br />

interactions and disease progression.<br />

7.196<br />

Coral Molecular Responses to Disease<br />

David ANDERSON* 1 , Sandra GILCHRIST 1 , Megan PEDERSEN 1<br />

1 Natural Sciences, New College of Florida, Sarasota, FL<br />

Reports of coral disease incidences have rapidly increased over the past three decades.<br />

Studies on coral disease published to date have largely focused on ecological surveys and<br />

the identification of causative agents. However, the mechanisms controlling coral<br />

“immune-like” responses and resistance to disease are not well understood. In this study<br />

we hypothesized that there are specific molecular responses to disease manifested by<br />

corals during periods of infection and exposure. During July of 2007 in Cayos Cochinos,<br />

Honduras, surface layer mucus samples were collected from diseased and healthy corals<br />

of the species Diploria strigosa and Siderastrea siderea, putatively affected by White<br />

Plague Disease, Dark Spot Syndrome, and Black Band Disease. From condensed mucus<br />

samples preserved in RNAlater (Ambion) we isolated coral RNA to analyze gene<br />

expression profiles by Differential Display Reverse Transcriptase PCR. PCR products<br />

were analyzed by 2 % agarose gel electrophoresis, and DNA bands that were<br />

differentially associated with diseased and healthy states were isolated, cloned, and<br />

sequenced. Sequences statistically similar to known coral and cnidarian genes were used<br />

to design Real-Time PCR probes to compare differential gene expression quantitatively.<br />

The putative molecular “immune-like” responses identified in this study will contribute<br />

to better understanding mechanisms associated with coral resistance and susceptibility to<br />

disease.<br />

Poster Mini-Symposium 7: Diseases on Coral Reefs<br />

7.197<br />

Release Of Antifungal Activities From Immune Challenged Sea Fans<br />

Nancy DOUGLAS* 1 , Steve LOWES 2 , C. Drew HARVELL 1<br />

1 Cornell <strong>University</strong>, Ithaca, NY, 2 Advion BioSciences, Ithaca, NY<br />

Sea fans offer an excellent system for studying innate immunity in corals because of their<br />

abundance, distribution, and ease of experimental manipulation. In addition, sea fans have a<br />

relatively well characterized susceptibility to harmful fungal infections that has been the basis<br />

for several disease ecology studies. The objectives of this study were to establish if sea fans<br />

respond to immune challenge by releasing potential protective compounds into the surrounding<br />

seawater and to begin to characterize the released activity. Antifungal, antibacterial and<br />

chitinolytic activity were assayed in the water surrounding sea fan pieces before and after<br />

immune stimulation. Sea fans were found to transiently release significant antimicrobial and<br />

chitinolytic activity between 1 and 48 hours after induction. Induced samples are being<br />

subjected to chromatographic separation followed by SDS-PAGE analysis and Mass<br />

Spectrometry (MS) to isolate and characterize active fractions. Preliminary analysis suggests<br />

that sea fans appear to release a mixture of various molecular weight protective compounds as<br />

an initial response to acute immune challenge. Further fractionation and analysis of these<br />

activities will identify individual compounds and their mode of action.<br />

7.198<br />

The Role Of Nitric Oxide in The Immune Defenses Of The Sea Fan gorgonia Ventalina<br />

Joyce STUCKEY* 1 , Nancy DOUGLAS 2 , Courtney SALTONSTALL 2 , Catherine<br />

HARVELL 3,4<br />

1 Zoology, Cornell <strong>University</strong>, Freeville, NY, 2 Ecology and Evolutionary Biology, Cornell<br />

<strong>University</strong>, Ithaca, NY, 3 Zoology, Cornell <strong>University</strong>, Ithaca, NY, 4 Ecology and Evolutionary<br />

Biology, Cornell <strong>University</strong>, Ithaca<br />

Coral disease outbreaks have increased and are linked with climate warming. One mechanism<br />

for increased disease in a stressed coral is through immune compromise. A centerpiece of<br />

innate invertebrate immunity in non-cnidarians is nitric oxide (NO), leading us to investigate its<br />

role in corals. In this study, the production of NO by nitric oxide synthase (NOS), a well<br />

studied component of vertebrate innate immunity, was measured to determine its role in the<br />

immune defenses of the sea fan Gorgonia ventalina. The NO production was measured using<br />

two methods: (1) the Griess reagent which causes a colorimetric change in the presence of NO<br />

that is quantified by a spectrophotometer and (2) confocal microscopy which allows for<br />

measurement of the fluorescence produced from the binding of a dye to NO. Both the<br />

constitutive NO production as well as production induced by several elicitors was measured. In<br />

the sea fans, NO production had great variability among individuals for both constitutive and<br />

induced levels. Identifying a more robust elicitor for NO production will help in future<br />

experiments to more clearly elucidate the role of NO in the immune response of sea fans.<br />

312

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