11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 5: Functional Biology of Corals and Coral Symbiosis: Molecular Biology, Cell Biology and Physiology
5.129
Variable Thermal And/or Irradiance Stress Responses Of Photosystem Ii Among
symbiodinium Spp. Isolated From Different Invertebrate Species
Ranjeet BHAGOOLI* 1,2 , Andrew C. BAKER 3 , Peter RALPH 4 , Michio HIDAKA 5
1 BioSciences, University of Mauritius, Reduit, Mauritius, 2 The Biodiversity and
Environment Institute, Reduit, Mauritius, 3 Rosenstiel School of Marine and Atmospheric
Science, University of Miami, Miami, FL, 4 Department of Environmental Sciences,
University of Technology, Sydney, Sydney, Australia, 5 Department of Chemistry,
Biology & Marine Sciences, University of the Ryukyus, Nishihara, Okinawa, Japan
We used Pulse Amplitude Modulated (PAM) fluorometry to measure the
photophysiological stress responses of symbiotic dinoflagellates (Symbiodinium spp.)
from 9 host species (one tridacnid clam, one anemone and 7 corals) from Zamami and
Sesoko Islands, Okinawa, Japan. We measured the maximum quantum yield of
photosystem II (PSII) in freshly isolated algae exposed to four different temperature
treatments (26oC, 29oC, 32oC and 34oC) and three different light treatments (0, 110 and
170 ìmol quanta m-2s-1). Chlorophyll fluorescence ratios (dark-adapted Fv/Fm) showed
significant variability in PSII response to both thermal and irradiance stress. We used
denaturing gradient gel electrophoresis (DGGE) analysis of ITS-2 ribosomal DNA to
identify the Symbiodinium used in our experiments, and found members of clade A, C
and D in these hosts. Photophysiological responses showed consistent differences
between distinct Symbiodinium types based on ITS-2 sequences. Hierarchical cluster
analysis of the combined responses of PSII to all temperature and/or irradiance treatments
revealed the following hierarchy, from most tolerant to least tolerant: D1a (Pavona
varians) = C9b (Platygyra ryukyuensis), A6 (Tridacna spp.) = C70 (Aiptasia spp.), C21a
(Galaxea fascicularis) = C1 (Stylophora pistillata and Pachyseris rugosa), C3 (Acropora
microphthalma) = C1c (Pocillopora damicornis). It is noteworthy that Symbiodinium C1
responded similarly irrespective of the host (Pachyseris rugosa or Stylophora pistillata)
from which they were isolated. These data suggest that different Symbiodinium ITS-2
types vary in stress tolerance, and that this tolerance is consistent among hosts.
Additional, data for isolates from Florida (USA), Heron Island (Australia) and Mauritius
are being analyzed.
5.130
Searching For Sulfur in symbiodinium: Dmsp Implications For Coral Symbioses
Denise YOST* 1 , Carys MITCHELMORE 1
1 Center for Environmental Science, Chesapeake Biological Laboratory, University of
Maryland, Solomons, MD
Symbiodinium, like other dinoflagellates, produce considerable amounts of
dimethylsulfoniopropionate (DMSP; mM concentrations intracellularly). DMSP
evolution from corals as dimethylsulfide (DMS) gas to the atmosphere can be substantial,
although it is unclear if this is via algal loss and/or translocation of DMSP/DMS through
coral tissues. DMSP lyase is present in some, but not all, DMSP producers and is
responsible for enzymatic cleavage of DMSP into DMS and acrylate. The roles and
functions of DMSP, DMSP lyase and DMSP breakdown products remain unclear in
Symbiodinium and coral symbioses as a whole. It is unknown if Symbiodinium contain
DMSP lyase. In addition, DMSP lyase has not been isolated from any coral species, but
has been isolated from other symbiotic organism host tissues (e.g. clams and flatworms).
DMSP and its breakdown products, DMS, dimethylsulfoxide (DMSO), methane sulfinic
acid (MSNA) and acrylate have antioxidant capabilities in other algal species. Given the
potential role of oxidative stress in coral bleaching, we focus on the role of DMSP as an
antioxidant. DMSP levels vary considerably in symbiont and host and may reflect a
coral’s sensitivity to bleaching events. Our findings indicate that DMSP lyase is present
in the Symbiodinium cultures examined and that baseline levels of DMSP and lyase vary
with Symbiodinium strain. In preliminary experiments, DMSP levels changed following
exposure to oxidative stressors (hydrogen peroxide, UV light). To characterize DMSP
production and lyase potential further, we collected various hard corals from Bermuda,
some of which were exposed to copper (a known elicitor of oxidative stress) for 48 hours,
which induced DNA damage. We will further analyze a variety of oxidative stress
endpoints coupled with DMSP and DMSP lyase assessments to investigate the role of
DMSP as an antioxidant in these corals.
5.131
A Mechanism Of Alloimmune Response in Primitive Phylum: Apoptosis in The
Gorgonian Coral Swiftia Exserta
Miguel MENDOZA 1 , Charles BIGGER* 1
1 Florida International University, Miami, FL
Previous studies on the Gorgonian Coral Swiftia exserta (Cnidaria, Anthozoan) immunology
have revealed specific intraspecific (alloimmune) responses to foreign tissue (Salter-Cid and
Bigger, 1991). These findings suggest that primitive forms of alloimmunity may have existed
prior to the deuterostome/ protostome phylogenic split. This study focused on the determination
of an apoptotic associated immune response in allograft tissue rejection in S. exserta using the
flow cytometry assay Guava PCA TUNEL Assay to indicate and quantify an apoptotic
response in induced cells. Following a five day induction period under closely monitored
conditions, dissociated cells from normal, autograft (self-graft) and allograft tissue samples
were examined for the presence of apoptosis. Flow cytometry data depicted pattern shifts in
allograft samples indicative of apoptotic activity. The results from the TUNEL Assay are
supportive of the hypothesis of apoptosis as the mechanism of tissue death in the allogeneic
response of the Gorgonian coral S. exserta.
5.132
Xenobiotic Metabolizing Enzymes in The Reef Building Coral Pocillopora Damicornis
Luc ROUGEE* 1 , Abby COLLIER 2 , Robert RICHMOND 1
1 Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawaii at
Manoa, Honolulu, HI, 2 Department of Tropical Medicine, Medical Microbiology and
Pharmacology, University of Hawaii at Manoa, Honolulu, HI
We examined the presence and rate of reaction of particular xenobiotic metabolizing enzymes
(XME) in the reef building coral Pocillopora damicornis, in order to develop a mechanistic
model for interpreting coral cellular profiles in response to pollutant exposure. The use of
pharmacological and cellular diagnostic tools, commonly implemented in determining
xenobiotic metabolism in humans, has proved successful in providing information of the
potential for analogous enzymes in corals. Previously established kinetic assays for Phase I
(Cytochrome P450 (CYP450) 1A, 2C9, 2D6, 2E1, 3A4 and CYP450 reductase) and Phase II
(UDP-glucuronosyltransferases, β-glucuronidase, Glutathione-S-transferase, and
Sulfotransferase) enzymes were optimized for the S9 postmitochondrial fraction of coral
protein. Positive results for members of both Phase I (CYP450 1A, 2E1, CYP reductase) and
Phase II (β-glucuronidase, Glutathione-S-transferase, and Sulfotransferase) enzymes has
revealed the presence of XME in corals. Enzymatic rates of reaction have been derived for a
reference time point and throughout the reproductive lunar cycle. Isolation and characterization
of select individual proteins will be investigated to confirm the specificity of these enzymes’
activities.
The ability to measure enzyme activity by proteins responsible for detoxification of pollutants
provides a means of identifying cause-and-effect relationships between particular stressors and
coral “health.” Additionally, examining changes in these activities allows the identification of
stress effects at the sublethal level, when management intervention has the greatest chance of
effectiveness. Finally, quantifying the magnitude and rate of cellular responses to xenobioticinduced
stress allows for measuring the efficacy of mitigation responses. By determining
changes to the metabolic pathways, that cause internal variations within in a coral which
otherwise visually appears ‘healthy’, we may be able to understand the cellular effects of
xenobiotics present in the environment.
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