11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 5: Functional Biology of Corals and Coral Symbiosis: Molecular Biology, Cell Biology and Physiology
5.112
Onset Of Symbiosis And Distribution Patterns Of Symbiotic Dinoflagellates in
Scleractinian Coral Larvae
Saki HARII* 1 , Naoko YASUDA 1 , Mauricio RODRIGUEZ-LANETTY 2 , Michio
HIDAKA 3
1 Graduate School of Engineering and Science, University of the Ryukyus, Okinawa,
Japan, 2 Centre for Marine Studies, University of Queensland, QLD, Australia, 3 Faculty of
Science, University of the Ryukyus, Okinawa, Japan
Establishment of symbiosis in early developmental stages is important for reef-building
corals. Corals spawn eggs and sperm or brood planula larvae and shed them directly into
the water. Some coral eggs or planulae receive symbiotic dinoflagellates (zooxanthellae)
directly from their parents, while others acquire them from the environment at each
generation. Although it has been experimentally demonstrated that azooxanthellate larvae
of some corals acquire zooxanthellae during larval stages, little is known about the timing
and process of the establishment of this symbiotic relationship. We examined 1) uptake
of zooxanthellae by larvae in six scleractinian corals and 2) both the timing of uptake and
distribution patterns of zooxanthellae in the planulae of two Acropora species under the
laboratory conditions. Zooxanthellae were isolated from adult conspecific colonies
(homologous) and added to planula larvae with or without Artemia sp. The number and
distribution pattern of zooxanthellae in the larvae were observed under a fluorescence
microscopy and/or on histological sections. Planulae of all the six species Acropora
tenuis, A. digitifera, A. nobilis, A. (Isopora) palifera, Favia pallida, and Ctenactis
echinata acquired zooxanthellae. The uptake of zooxanthellae occurred 5 and 6 days after
spawning in A. nobilis and A. digitifera, respectively. The number of incorporated
zooxanthellae in the larvae increased over the experimental periods. Histological
observations also showed that zooxanthellae were incorporated by larvae when they
formed a well-developed mouth and coelenterons. The larvae of A. digitifera
incorporated more zooxanthellae in the presence of homogenized Artemia sp. The present
results suggest that coral larvae of many species can acquire zooxanthellae during the
larval stage and that larval feeding behavior plays an important role in the acquisition of
zooxanthellae.
5.113
The Cell Ecology Of symbiodinium in Soritid Foraminifera
Scott FAY* 1 , Michele WEBER 1 , Jere LIPPS 1
1 Integrative Biology, University of California, Berkeley, Berkeley, CA
Amphisorus, Marginopora, and Sorites foraminifera host diverse lineages of
Symbiodinium dinoflagellates. It is not uncommon for an individual foraminifer to host
mixed populations of Symbiodinium from multiple clades. Fine-scale examination of
individual foraminifera reveals a pattern where certain genotypes of symbiont are
enriched towards the center of the test. In order to explore what ecological forces are at
work that might explain these observations, we identify five factors that potentially
determine which symbionts are found in these hosts: vertical transmission, specificity,
regulation, competition between symbiont lineages, and availability from the
environment.
5.114
Gene Expression in The Coral, montipora Capitata, After Fragmentation And
Transplantation: Insight Into Transcriptional Stress Response Using Real-Time Pcr
Marissa B. HIRST* 1 , Anderson B. MAYFIELD 1 , Ruth D. GATES 1
1 Department of Zoology, University of Hawaii, Manoa, Kaneohe, HI
Most tools used to assess coral health rely on biological responses that are temporally removed
from the onset of stress i.e. bleaching and mortality. To manage corals more effectively,
techniques that detect shifts in health earlier in the biological response are needed. Gene
expression responds rapidly to the onset of stress and therefore represents a framework for
developing such tools. This study explores the expression of the heat shock protein 70 (hsp70)
gene as a potential biomarker in the scleractinian coral Montipora capitata and its
endosymbiotic algae, Symbiodinium. Fragments of coral were removed from parent colonies
(n=10) and placed at the same depth as the parent colony (8 feet) to recuperate. In order to
assess the impact of fragmentation, hsp70 expression was assessed in fragments (n = 5)
collected weekly during the one-month recuperation. In a second experiment, conducted postrecuperation,
a subset of fragments (n = 5) were elevated three feet in the water column and
controls maintained at 8 feet. Fragments were collected in a time series over one week to
explore differences in hsp70 expression in the host and symbiont as a result of the depth
transplantation. Gene expression was quantified using Real-Time Polymerase Chain Reaction
normalized to an exogenous RNA spike and genome copy number of hsp70 in Symbiodinium.
The expression of hsp70 was low in the coral and symbiont in fragmented corals. Hsp70
expression in coral hosts transplanted shallower was similar to control fragments, however,
symbiont hsp70 was up regulated in these transplants relative to controls. These results suggest
that expression of the hsp70 gene is not altered greatly by fragmentation and that hsp70
expression in Symbiodinium is more sensitive to changing environmental conditions than host
hsp70 gene expression.
5.115
An 'in Vitro' Method Of Coral Health Assessment: A New Approach
Maya VIZEL* 1 , Esti KRAMARSKY-WINTER 1 , Craig DOWNS 2 , Yossi LOYA 1
1 Dept. of Zoology, Tel Aviv University, Tel Aviv, Israel, 2 Haereticus Environmental Labs,
Clifford, VA
Assessing coral health in laboratory conditions can provide us with fast and easy results in a
controlled environment. In order to do so, a new method for culturing coral tissue and polyp
explants has been developed in this study. This method does not require the use of large aquaria
for coral growth or proximity to coral reef, making it available worldwide. In order to create
these tissue explants, tissue from adult coral of Fungia granulosa was mechanically removed.
Approximately 24 hours after excision tissues were transferred to FSW (filtered sea water) and
optimal growth conditions were examined. Results indicate that manipulating environmental
parameters such as temperature and light we can produce explants that are either maintained in
a tissue state or developed into small polyps. We further succeeded in developing tissue and
polyp lines by sub-culturing the explant-derived polyps, thus providing continuous cultures
from single genetic lines. Because these coral tissue/polyp explants are genetically identical and
can be propagated multiple times, they can be used for short or long term studies in coral health
assessment. To exemplify such a use, the effect of various concentrations of the antibiotic
cycloheximide, often used in agriculture, was used on a line of these genetically identical
polyps and found to cause complete bleaching at concentrations as low as 10mg/L. This
technique provides a method for achieving fast results concerning coral physiology and be
useful in ecotoxicological studies, under laboratory conditions.
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