| Summary: | 碩士 === 國立東華大學 === 海洋生物科技研究所 === 99 === In the present study, we investigated the correlation between lipid components and cell proliferation among differernt clades (Clade B1, E1 and C1) of Symbiodinium. The clades B1, E1 and C1 of Symbiodinium were cultivated for three days under 12L/12D photoperiod and cell proliferation was analzyed using flow-cytometer. The cell cycle propogation of the Symbiodinium clade B1 and E1 can be synchronized under 12L/12D photoperiod. 40~60％ of clade B1 underwent cell proliferation during three-day cultivation. Only 20% of clade E1 proliferated during the first day and 30~40％ during the second and third days. The cell cycle of clade C1 seems to be longer than 24 hours since only 15% proliferated every 24 hours. In addition, the results also showed that the carbon fixation product of photosynthesis is transformed to starch and lipid. The starch content of clade B1 and E1 gradually increased during light period, but decreased during dark. These starch contents of clade B1 and E showed clear circadian rhythm. However, there was no difference in Clade C1 and its starch content was low. Furthermore, we analyzed their lipid components. The levels of fatty acid and phosphatidylethanolamine varied during cell cycle, but the levels of wax ester and phosphatidylcholine did not. The triglycerides can only be found in the Symbiodinium clade C1, but the level did not vary. In summary, the starch and the fatty acids of Symbiodinium are synthesized when illuminated, and once enough is accumulated, Symbiodinium can pass the check point and start progression of cell cycle. Biosynthesis of phosphatidylethanolamine is also essential to cell division in order to synthesize new cell membrane and cell wall. The fact that Symbiodinium clade C1 synthesizes more triglycerides but little starch may block phosphatidylethanolamine biosynthesis, and therefore slow down cell division and cell proliferation.
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