Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/35954
標題: 芝麻油體成熟過程中三個主要成份變化之研究
Ontogeny of oil bodies Monitored with the accumulation of their three essential constituents in developing Sesame Seeds
作者: 彭及忠
Peng, chi-chung
關鍵字: oil body;油體;oleosin;triacylglycerol;油體膜蛋白;三酸甘油酯
出版社: 農業生物科技學研究所
摘要: 
中文摘要植物種子內有一儲存三酸甘油脂的胞器稱為油體,是由一層半
單位膜的磷脂質及鹼性的油體膜蛋白所包圍,油體上同時具有兩類油體膜
蛋白異構體。芝麻種子在發育時,三酸甘油脂及兩個油體膜蛋白異構體17
kDa和15 kDa、明顯的積存於油體中。在芝麻種子發育期過程,油體膜蛋
白17 kDa比油體膜蛋白15 kDa晚出現,但在最後成熟種子中油體膜蛋白17
kDa卻為最主要的蛋白。油體上主要的磷脂為磷脂膽鹼(
phosphotidylcholine),由實驗結果證明油體形成是來自內質網,其三
酸甘油脂及磷脂膽鹼是在內質網內合成而油體膜蛋白則是直接標的到正在
發展的油體上並未經由內質網的包裝。在油體形成早期發現有少量的小油
滴形成,此小油滴可能因缺少油體膜蛋白構成的立體障礙而結構不穩定;
維持小油滴短暫的穩定度可能是來自內質網本身的磷脂。在油體形成的最
後成熟期發現油體膜蛋白17 kDa比油體膜蛋白15 kDa的含量高,且在種子
發芽時含油體膜蛋白17 kDa較多的油體有比較早被利用的傾向,顯示油體
膜蛋白17 kDa在油體表面的組成比例與其發芽時先被利用有相當的關係。

ABSTRACTPlant seeds store triacylglycerols in discrete
organelles called oil bodies. An oil body is surrounded by a
half-unit membrane of phospholipids and alkaline proteins termed
oleosins. Triacylglycerols and two oleosin isoforms of 17 and
15 kDa were exclusively accumulated in oil bodies of developing
sesame seeds. During seed development, oleosin 17 kDa emerged
later than oleosin 15 kDa, yet developed subsequently into the
most abundant protein in mature oil bodies.
Phosphotidylcholine, the major phospholipid in oil bodies, was
amassed in ER during the formation of oil bodies. The results
support that oil bodies originate from ER with actively
synthesized triacylglycerols and phosphotidylcholine whereas
oleosins target onto budding oil bodies directly without
packaging in ER. Prior to the formation of oil bodies, few oil
droplets of smaller size were observed in vivo and in vitro.
These oil droplets were unstable presumably due to the lack of
steric hindrance shielded by oleosins. The temporary
maintenance of these droplets as small entities seemed to be
provided by phospholipids wrapped in ER. Oil bodies assembled
in late developing stages possessed a higher ratio of oleosin 17
kDa over oleosin 15 kDa and were utilized earlier during
germination. It seems that the proportion of oleosin 17 kDa on
the surface of oil bodies is related to the priority of their
utilization.
URI: http://hdl.handle.net/11455/35954
Appears in Collections:生物科技學研究所

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