11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 5: Functional Biology of Corals and Coral Symbiosis: Molecular Biology, Cell Biology and Physiology
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Introduction Of Foreign Genes in symbiodinium: A Strategy To Study The
Function Of The Cytoskeleton And Other Proteins
Marco VILLANUEVA* 1 , Tania ISLAS-FLORES 2 , Claudia MORERA 1 , Roberto
IGLESIAS-PRIETO 1 , Patricia THOMÉ-ORTIZ 1 , Frantisek BALUSKA 3 , Diedrik
MENZEL 3 , Boris VOIGT 3
1 Unidad Académica Puerto Morelos, Instituto de Ciencias del Mar y Limnología-UNAM,
Puerto Morelos, Mexico, 2 Plant Molecular Biology, Instituto de Biotecnología-UNAM,
Cuernavaca, Mexico, 3 Institute of Cellular and Molecular Botany, University of Bonn,
Bonn, Germany
Two proteins were visualized through the use of their corresponding fusions to the
reporter green fluorescent protein (GFP). First, the actin microfilaments in
Symbiodinium cells in culture were visualized through the introduction of an actinbinding
domain of fimbrin (ABD2) fused to GFP. In addition, the constitutively
expressed distribution of a receptor for activated protein kinase C (RACK1) from the
plant Arabidopsis thaliana also fused to GFP was assessed in Symbiodinium
kawagutii cells. In both cases, the plasmid vectors containing the 35S constitutive
promoter and the corresponding fusions, also contained resistance genes for selection of
the transformed cells. The ABD2-GFP construct was located in a pCAMBIA 1390 vector
with a resistance gene to hygromycin, and the GFP-RACK1 construct was in pCB302
with a resistance gene to the herbicide Basta. The plasmid constructs were introduced
by a brief treatment of the cells with a bead beater in the presence of polyethylene glycol
and glass beads. The cells were grown in ASP-8A with the corresponding selection agent.
The selected cells were analyzed at the initial stages and after prolonged cell culture with
normal light and epifluorescence under a Zeiss Axiostar Plus FL microscope and a Zeiss
confocal microscope. In the case of the GFP-RACK1 expression, the fluorescence of the
GFP was evident and reflected the expression of the protein introduced in the
construction, which was throughout the cell in the cytoplasmic matrix. In the case of
ABD2-GFP, the fluorescence was evident in the cytoskeletal matrix. This strategy will be
useful for the study of the cytoskeleton and other proteins relevant in various biological
processes in Symbiodinium.
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Redistribution Of Endosymbiotic Dinoflagellates Between Different Tissue Layers
in Coral Larvae
Hui-Ju HUANG* 1 , Li-Hsueh WANG 1,2 , Hui-Jun KANG 1 , Lee-Shing FANG 3 , Chii-
Shiarng CHEN 1,2
1 Coral Research Center, National Museum of Marine Biology and Aquarium, Pingtung,
Taiwan, 2 Institute of Marine Biotechnology, National Dong Hwa University, Pingtung,
Taiwan, 3 Cheng Shiu University, Kaohsiung, Taiwan
In adult cnidarians, symbiotic dinoflagellate Symbiodinium is usually located in the
gastrodermis. However, during early development, they have also been observed in
oocytes or the epidermis of the planula larva. It indicates that the cellular site of the
cnidaria-dinoflagellate endosymbiosis may be regulated developmentally, highlighting a
dynamic and complicated interaction between the host cell differentiation and the
symbiont. This study first examined the distribution of the Symbiodinium population in
tissue layers of planula larvae in the stony coral Euphyllia glabrescens. Here,
Symbiodinium were redistributed from the epidermis to the gastrodermis, at a rate that
was fastest during early planulation and then decreased prior to metamorphosis. Based on
the whole embryo analysis and the transmission electron microscopic examination, the
redistribution of symbionts is attributed to a direct translocation of the Symbiodinium sp.
from the epidermis to the gastrodermis. The translocation can be inhibited by treatments
with nocodazole and DCMU (3-(3, 4-Dichlorophenyl)-1, 1-dimethylurea), leading to the
retardation of larval settlement and metamorphosis. This suggested the involvement of
host cytoskeleton and photosynthesis of the symbiont in regulating the translocation.
Finally, using MALDI imaging mass spectrometry and synchrotron radiation-based
infrared microspectroscopy, the timing of Symbiodinium translocation was shown to be
correlated with changes of spatial distribution and composition of lipid bodies (LB) in the
host cell. The result indicates that the Symbiodinium translocation is regulated by the host
tissue.
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Juvenile Corals Acquire More Carbon From High-Performance Algal Symbionts
Neal CANTIN* 1,2 , Madeleine VAN OPPEN 2 , Bette WILLIS 1 , Jos MIEOG 3 , Andrew NEGRI 2
1 James Cook University, Townsville, Australia, 2 Australian Institute of Marine Science,
Townsville, Australia, 3 University of Groningen, Haren, Netherlands
Algal endosymbionts of the genus Symbiodinium play a key role in the nutrition of reef
building corals and strongly affect the thermal tolerance and growth rate of the animal host. We
used 9 month old Acropora millepora juveniles that had a common parentage and had been
experimentally infected with either Symbiodinium C1 or D immediately following
metamorphosis to test the influence of genetically distinct symbionts on the physiological
performance of reef-building corals. Here we report that the capacity of photosystem II
(rETRMAX) is 87% greater in Symbiodinium C1 than in Symbiodinium D in hospite, and
that 14C photosynthate incorporation (carbon based energy) into juvenile tissues of the coral, A.
millepora, is doubled in C1 corals. Greater carbon delivery from Symbiodinium C1 provides
juveniles with a competitive advantage since rapid early development typically limits mortality.
Symbiodinium C1 corals, however, lose this competitive advantage under stressful conditions
that limit electron transport. These findings significantly advance our current understanding of
symbiotic relationships between plants and animals and describe a photophysiological
mechanism that may enhance the growth and resilience of corals facing an uncertain future
climate.
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Determinant Of Histoincompatibility Reactions in Corals
Michio HIDAKA* 1 , Diah PERMATA 2
1 Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Nishihara,
Okinawa, 903-0213, Japan, 2 Diponegoro Univeristy, Semarang, Indonesia
In colonial corals, two allogeneic colonies display various contact reactions such as rejection,
non-fusion, overgrowth, and fusion, while clonemates invariably fuse with each other. It has
been suggested that historecognition system is not fully developed in early stages of
development in some corals. The objective of this study was to investigate whether outcomes of
allogeneic contact are determined by the genetic relatedness of the pairs or influenced by
developmental stages. We observed the interface of allogeneic pairs of primary polyps and adult
colonies of Pocillopora damicornis under light and electron microscopes. We found that
pairs of primary polyps derived from different colonies of P. damicornis showed either
fusion, non-fusion, or incompatible fusion response. In incompatible fusion, tissues were
continuous but a white zone with few zooxanthellae was formed at the interface and polyps at
the interface zone were sometimes absorbed. The skeleton at the interface was also continuous
but irregular in shape. Shrunk nuclei and large extracellular spaces suggest that cell death via
apoptosis occurred at the interface region. Incompatibly fused pairs transformed to non-fusion
after several months, though the speed of this shift differed among pairs. Shrunk nuclei and
extracellular spaces were also observed in non-fused pairs of adult branches. Even in non-fused
pairs, tissues of the paired branches touched each other at the growing edge and competition
occurred at a cellular level. When two allogeneic tissues contact with each other, some pairs
show stable fusion resulting in chimeric colonies, while others transform from temporary fusion
to incompatible fusion response, which later transform into non-fusion response. The speed of
this shift of contact reaction might be determined by the genetic relatedness of the pairs rather
than developmental stages of the pairs.
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