11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 5: Functional Biology of Corals and Coral Symbiosis: Molecular Biology, Cell Biology and Physiology
5.145
The Effect Of Salinity On The Wound Healing Rate Of The Gorgonian Coral
Swiftia Exserta
Maria GONZALEZ* 1 , Ana RESTREPO 1
1 Dept. of Biological Sciences & Comparative Immunology Institute, FIU, Miami, FL
To protect their integrity, gorgonian coral colonies have the ability to repair tissue
damage inflicted by other organisms or mechanical injury. To avoid the potential for
harmful larval settlement it is important for the colony to cover bare axial skeleton as
well as maintain the tissue integrity. This study examined the effect of different salinities
on the rate of wound healing in the gorgonian coral, Swiftia exserta. Three trials were
performed with nine S. exserta colonies (n=9). In each trial, a 4 cm branch from each
colony was suspended in aquaria at salinities of 30, 35 and 40 0/00 for the first trial and
32, 35, and 40 0/00 for the second and third trials. In the center of each branch the tissue
over a 4 mm length was totally removed from the axial skeleton. The branches were
scored daily until the two tissue fronts met. That time, in days, was used as the endpoint.
The healing rates were compared within each trial using a 0.05 significance level.
In the first trial there was no healing and significant branch death at 30 0/00.
Accordingly, 32 0/00 was used in the other trials. There was no significant difference
between the healing rates at 32 and 35 0/00. The healing was significantly faster at 40
0/00 than either 32 or 35 0/00. These data suggest that a non-lethal difference in salinity
may affect gorgonian coral defense systems.
5.146
Functional Genomic Approaches To The Study Of Coral Immunity
Morgan MOUCHKA* 1 , Jason ANDRAS 1 , Drew HARVELL 1
1 Ecology and Evolutionary Biology, Cornell University, Ithaca, NY
Sea fan aspergillosis, a disease caused by the fungal pathogen Aspergillus sydowii, has
caused extensive mortality in the sea fan coral Gorgonia ventalina in the Caribbean for
the past 15 years. One hypothesis to explain disease outbreaks is that host immunity is
compromised by environmental stress. Although the sea fan-Aspergillus pathosystem has
been well studied, we still lack a basic understanding of the physiological mechanisms
that underlie coral immunity. We are developing cDNA microarrays to identify genes
involved in the G. ventalina immune response. Here we report results from preliminary
steps, including the construction of cDNA libraries, sequencing of clones to generate
Expressed Sequence Tags (ESTs), and annotation of the ESTs to identify candidate genes
to be printed on microarrays. Annotation of EST’s has already identified a number of
immune related genes, such as those that encode for superoxide dismutase (antioxidant
defense), fibronectin (wound healing), ficolin (pattern-recoginition), immunophilin
(immunosuppressant agent and heat shock protein binder), and techylectin (non-self
recognition). Work is ongoing to verify and quantify the expression patterns of these
genes in response to experimental immune challenge. The final results of this study will
provide insight into the complex molecular responses that occur from the onset of sea fan
infection to the ultimate fate of survival or mortality. This information will prove
valuable not only to the study of other coral pathosystems, but also to the study of
invertebrate innate immunity in general.
5.147
The Genetic Structure Of The Coral May Control Host-Symbiont Specificity in The Sea
Of Cortez
Jorge H. PINZÓN C.* 1 , Tye PETTAY 2 , Todd C. LAJEUNESSE 2
1 Department of Biology, Penn State University, State College, PA, 2 Department of Biology,
Penn State University, University Park, PA
Coral-symbiodinium symbioses in the Sea of Cortez (Gulf of California) appear to have high
levels of specificity. Different colonies of Pocillopora spp. contain unique and stable
associations with either symbiodinium type D1 or type C1b-c. The establishment and evolution
of unique host-symbiont associations has been attributed to several factors including
environmental conditions, geographical isolation, the taxonomic identity of the host and the
symbiont, or combinations of the aforementioned. In La Paz, Baja California, Pocillopora spp.
colonies with holobiont combinations similar to those found elsewhere in the Eastern Pacific
are coexisting under the same environmental conditions. This indicates that neither the
environment nor geographical isolation have played a primordial role in the formation of coralsymbiodinium
associations in the Gulf. Genetic analysis using two microsatellite markers
suggests that different allele frequencies in Pocillopora spp. may be associated with the
dominant type of symbiont (D1 or C1b-c). Differences among host genotypes may explain, in
part, the distribution of one species of symbiont over another in colonies exposed to identical
environmental conditions and evolutionary processes.
5.148
Photosmoregulation: Evidence Of Host Behavioral Photoregulation Of An Algal
Endosymbiont By The Acoel convolutriloba Retrogemma As A Means Of Non-
Metabolic Osmoregulation
Thomas SHANNON* 1
1 Ecology, University of Georgia, Athens, GA
This study of the acoel Convolutriloba retrogemma suggests that observed basking behaviors of
the animal function not only in photoregulating its algal endosymbiont, but serve as a novel
method of host osmoregulation. The study further shows that intercellular change in osmotic
pressure resulting from photosynthesis is the photoregulatory stimulus. The term
“photosmoregulation” is offered to describe the process. The study examines the
photobehaviors of the acoel, the factors affecting these behaviors, their regulatory functions,
and how they affect or are affected by the acoel’s algal endosymbiont. The first behavior
detailed is a step-up, photophobic response to sudden increases in light; this variable response is
blue-light-mediated and triggered by visual, photic stimuli. The second behavior detailed is a
phototactic-photoaccumulative behavior responsible for observed mass basking formations; this
behavior is regulated by the photosynthetic activity of the algal endosymbiont. The effects of
holozoic starvation are examined, particularly as they apply to host phototactic and
photoaccumulative behavior. The data show that contrary to expected behavior, starved acoels
do not seek out areas of high intensity light, but instead retreat to areas of lower intensity. The
results of this study support a hypothesis that the basking behaviors of these acoels serve as
methods of photoregulating their algal endosymbionts. The results further suggest that starved
acoels have diminished capabilities for processing translocated algal photosynthates and that
under high-light conditions a build-up of these compounds results in hyposmotic stress in the
animals.
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