| Summary: | 碩士 === 國立東華大學 === 海洋生物科技研究所 === 98 === The regulatory mechanism of the mutualistic association in coral–dinoflagellates endosymbiosis has been attracting intensive examination during the past decades. In previous study, the host lipid bodies (LBs) extruded from symbiotic dinoflagellates have been identified that are closely interacted with the status of endosymbiosis in the stony coral Euphyllia glabrescens (Patton and Burris, 1983; Luo et al., 2009). In the present study, the formation of LBs during the embryonic development in two brooding stony coral Seriatopora hystrix and Pocillopora damicornis are investigated. By cryosection, TEM (transmission electron microscopy) and lipid analysis using HPTLC (high performance thin layer chromatography), we determined the changes of LB distribution and major lipid components in larvae. In newly released planula larva, large lipid bodies (~20 μm) as parental nutrient called yolk bodies (YBs) filled the body cavity. The formations of LBs appeared in both epidermis and gastrodermis of settled larvae during development. From section-observation, the epidermal LBs gradually increased at the 1st day after release and decreased after three or four weeks. Differentiating the gastrodermal LBs was hard due to the existence of YBs, but the YBs were consumed during the time; YBs almost ran out in larvae after four weeks. However, the lipid analysis of developing larvae revealed the change of major components from wax esters to triglycerides. We suggest that the dynamic changes of LB formation and YB depletion are correlated to the increased triglyceride and decreased wax esters concentration respectively during the first four weeks after release.
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