11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 5: Functional Biology of Corals and Coral Symbiosis: Molecular Biology, Cell Biology and Physiology
5.137
Wound Healing in The Gorgonian Coral Swiftia Exserta
Charles BIGGER* 1 , Cecile OLANO 2
1 Biological Sciences & Comparative Immunology Instiitute, Florida International
University, Miami, FL, 2 USDA ARS, Miami, FL
Gorgonian corals, like all sessile marine organisms, are susceptible to tissue damage from
predators, mechanical impact and abrasion. In addition to a need for sealing the wound
to maintain integrity and homeostasis, these animals have an additional threat if the axial
skeleton is exposed. Exposed axial skeleton can provide a substrate for larval settlement
and a subsequent possibility for overgrowth or other negative interaction. Accordingly,
on-going examinations are being made of the wound healing/regeneration process in the
gorgonian coral, Swiftia exserta, a gorgonian lacking zooxanthellae.
Colonies of S. exserta from the Southeast coast of Florida were maintained in the
laboratory at FIU. This study was designed as a time series of gross and histological
observations of the response to a 5 mm removal of all tissue from the axial skeleton of a
2.5 cm colony branch. Eight series were fixed and processed for histology at times: 1 hr,
12 hrs, 1 day, 3 days, 5 days, 6 days and 1 week.
Details will be presented correlating the changes at the cellular level with observations at
the organismal level. In summary, the sequence of observed events was: a rapid sealing
of the tissue openings; formation of specialized moving fronts, mostly composed of
granular amoebocytes, that travel across the bare axial skeleton; fusion of the two fronts;
and a subsequent filling-in and restoration of the normal anatomy in the wound area,
without scaring. While there did appear to be a migration of cells into the area in the
process, there was also evidence for a tissue spreading not seen in another investigation
with the gorgonian Plexaurella fusifera.
These observations confirm that Swiftia exserta is well adapted to recover from injury
under normal conditions and provide information concerning the underlying process and
cell functions.
5.138
Micro-Niche Partitioning And The Photobiology Of symbiodinium Associated
With montastraea Faveolata
Dustin KEMP* 1 , Xavier HERNANDEZ-PECH 2 , Roberto IGLESIAS-PRIETO 2 ,
Gregory SCHMIDT 3 , William FITT 1
1 Odum School of Ecology, University of Georgia, Athens, GA, 2 Unidad Academica
Puerto Morelos, Puerto Morelos, Mexico, 3 Department of Plant Biology, University of
Georgia, Athens, GA
The dominant Caribbean reef building coral Montastraea faveolata has been known to
associate with multiple genotypes of Symbiodinium for over a decade. The unique ability
to simultaneously host diverse assemblages of Symbiodinium makes M. faveolata an ideal
species to examine the physiology of genetically different coral-symbiont associations.
Using micro-sampling techniques we identified up to three distinct genotypes
representing three different clades of Symbiodinium co-occurring within M. faveolata
from the northern portion of the meso-american barrier reef in Puerto Morelos, Mexico.
Coral colonies were screened for symbiont diversity using denaturing gradient gel
electrophoresis (DGGE) of the ITS-2 region of nrDNA and specific zones were chosen
reflecting Symbiodinium diversity. Symbiodinium zonation patterns were primarily
determined by locally prevalent light fields on M. faveolata colonies. We found
Symbiodinium type B17 to be the dominant symbiont found in high-light areas within the
colony, while type C7 was found to be the dominant symbiont in low-light areas.
Intermediately, Symbiodinium type A3 was found to be mixed among some of the highlight
samples but was never observed as the dominant symbiont. Coral samples were
collected four times a year from various zones and a series of physiological parameters
were measured examining Symbiodinium population structure and photobiology. Photophysiological
responses as determined by P vs E curves revealed genetically different
symbiont types displayed differential high-light or low-light photoacclimatory responses.
Further investigation of specific light zones using common coral-symbiont parameters
including symbiont cell densities, chlorophyll content, and absorbance spectra analysis
confirmed a high degree of Symbiodinium niche specialization and photoacclimation
processes emerging annually within M. faveolata colonies.
5.139
Various Symbiodinium Spp. Distributed Among Differing Morphotypes And Genotypes
Of Porites Panamensis From The Gulf Of California, Mexico
David Arturo PAZ-GARCÍA* 1,2 , Todd C. LAJEUNESSE 3 , Héctor Efrain CHÁVEZ-
ROMO 1,2 , Francisco CORREA-SANDOVAL 2 , Hector REYES-BONILLA 4
1 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, Mexico,
2 Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California,
Ensenada, Mexico, 3 Department of Biology, The Pennsylvania State University, Pennsylvania,
PA, 4 Departamento de Biología Marina, Universidad Autónoma de Baja California Sur, La Paz,
Mexico
The degree of specificity between coral hosts and endosymbiotic dinoflagellates in the genus
Symbiodinium (zooxanthellae) affects the potential for responses to environmental change
through partner recombinations. We examined the diversity of zooxanthellae populations in two
morphotypes of Porites panamensis in the southern of the Gulf of California. Additionally, we
analyzed the host genetic information by allozyme electrophoresis in order to demonstrate if the
species of symbiont corresponds with the genotype and/or morphotype of the host individual.
The specimens (N = 20) were colleted at shallow coral communities (1-2 m). Symbiodinium
C66a and C1 associated with columnar colonies of P. panamensis while C66 occurred
commonly in massive forms. We found no host genotypes specific for species of symbiont.
However, differences on host genotype frequencies were observed by Markov chain method
between massive C66 and columnar C1 colonies (X 2 = 21.378, d.f. = 10, p < 0.01). An UPGMA
cluster analysis using between samples showed massive C66 and columnar C66a symbionts
clustered together before joining the columnar C1. These data indicate that differences in host
genetic make-up may, in part, explain the presence of different Symbiodinium among
individuals of a host population existing in the same environment. The potential influences of
brooding and maternal transmission to the coevolution of specific partner combinations could
be generating the pattern observed.
5.140
Rapid And Highly Precise Measurements Of symbiodinium Number Using A Coulter
Counter
Carlo CARUSO* 1 , Joshua MEISEL 2 , Santiago PEREZ 1 , John PRINGLE 1
1 Stanford University, Stanford, CA, 2 University of Queensland, St. Lucia, Brisbane, Australia
Our lab is focused on helping develop the Aiptasia-Symbiodinium model system for studies of
the molecular and cellular biology underlying the cnidarian-dinoflagellate symbiosis. A major
part of our current effort is to develop methods that will allow more facile, versatile, and
rigorous experimentation. A limitation for many kinds of studies has been that the methods
available for determining symbiont loads (i.e., the number of symbionts per unit of host
material) have been time-consuming, imprecise, and/or inaccurate. Using the Coulter Counter
and well established assays of total protein, we have developed a rapid, highly precise, and
probably highly accurate (although this is more difficult to judge) method for determining
symbiont loads. The method can be used with cultured Symbiodinium or with algae isolated by
homogenization of host tissue. It can also be used with fresh, fixed, or frozen material, so that
samples can be analyzed after an experiment is completed and, if necessary, using an instrument
at a remote location. The method allows changes in the symbiont load to be detected with at
least 8-fold more precision and at least 25 times more rapidly than is possible with a counting
chamber (hemocytometer). This dramatically improves researchers’ ability to detect small
changes in algal density during time-course experiments or between treatment groups. The
method also has some limitations, which will be discussed.
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