Immunoelectron microscopic studies on the behavior of photosynthetic protein in Euglena

裸藻光系统II的叶绿素a/B结合蛋白（LHCP II）的前体是含有多个LHCP II拷贝的大的多聚蛋白，所述LHCP II拷贝通过保守的十肽共价连接。光诱导的LHCP II合成在裸藻中控制在翻译水平，而不是在高等植物和其他藻类中发现的转录水平。在促进类囊体中LHCP II合成和积累的条件下，可以通过免疫金电子显微镜在高尔基体中观察到与抗LHCP II抗体的反应。在同步细胞中用免疫金电镜和在正常光诱导叶绿体发育的细胞中用H_2[^ S]O_4脉冲标记的方法测定了LHCP Ⅱ在高尔基体中出现的动力学<35>，表明新生LHCP Ⅱ在叶绿体输入和类囊体插入之前被转运到高尔基体。表明存在LHCP II脱辅基蛋白。不可能在整个细胞周期中提供这种结构的系统数据，因为它很小，很难找到。需要进一步的实验来澄清COS的性质及其在LHCP II合成中的作用。

The precursors to the Euglena light-harvesting chlorophyll a/b binding proteins of photosystem II (LHCP II) are large polyproteins containing multiple copies of LHCP II covalently joined by a conserved decapeptide. Light induced LHCP II synthesis is controlled at the translational level in Euglena rather than the transcriptional level as found in higher plants and other algae. Under conditions promoting LHCP II synthesis and accumulation in the thylakoids, a reaction with anti-LHCP II antibody can be observed by immunogold electron microscopy in the Golgi apparatus. The kinetics of LHCPII appearance in the Golgi apparatus as measured by immunogold electron microscopy in synchronous cells and by pulse labeled with H_2[^<35>S]O_4 in cells undergoing normal light-induced chloroplast development suggests that nascent LHCP II is transported to the Golgi apparatus prior to chloroplast import and thylakoid insertion.The few views of the compartmentalized osmiophilic body (COS) that we have obtained indicate the presence of LHCP II apoprotein. It is not possible to provide systematic data for this structure throughout the cell cycle since it is small and difficult to find. Further experiments are required to clarify the nature of the COS and its role in LHCP II synthesis.