Cytological and cell biological study on the chloroplast nucleloid-DNA containig pyrenoids.

研究了含有叶绿体类核DNA的类蛋白核在淡水绿色藻类中的分布。新发现3属4种（Trebouxia sp. T. potteri、Parietochloris pseudoalveolaris、Stichococcus bacillaris）和另外两种未鉴定的绿色鞭毛虫。此外，在2属3种植物（Tetrasporagelinosa，T.lubricus，Diplosphaerachodatii）中还发现了其他类型的叶绿体类核，其类核DNA定位在类核淀粉鞘的外侧。研究了仅进行无性繁殖的假泡藻整个生活史中叶绿体类核的行为。在生殖细胞（游动孢子或不动孢子）分化过程中，叶绿体不断分裂，蛋白核随之消失，类核DNA以小颗粒的形式散布在叶绿体中。利用多核绿色藻（Caulerpa）的叶绿体蛋白核，通过叶绿体蛋白核DNA和Rubisco的结合，建立了叶绿体及其蛋白核的分离方法。结果表明，蛋白核基质由六种蛋白质组成，分别为97 KDa、63 KDa、54 KDa、28 KDa、14 KDa和DNA。在NaCl处理蛋白核组分得到的上清液中，存在54KDa、14KDa和44KDa蛋白。前两种蛋白分别对应于Rubisco的大亚基和小亚基。

Distribution of pyrenoids which contain the chloroplast-nucle- oid DNA was surveyed in fresh-water green algae. It was newly found in three genera and four species(Trebouxia sp. T. potteri, Parietochloris pseudoalveolaris, Stichococcus bacillaris) and two other unidentified green flagellates. In addition,other new-type of chloroplast nucleoids was discovered in two genera and three species(Tetraspora gelatinosa,T.lubricus,Diplosphaera chodatii), in which the nucleoid DNA lacalizes outside around the sheath of pyrenoid starch. The behavior of chloroplast nucleoids was investigated throughout the whole life cycle of P.pseudoalveolaris in which only asexual reproduction takes place. During of differentiation of reproductive cells (zoospores or aplanospores) the chloroplast repeated to divide and pyrenoids disappeared concomitantly, nucleoid DNA scattered as many small granles through chloroplasts. As the reproductive cells differentiated into the vegetative cells pyrenoids were reformed and nucleoid DNA also began to localize into the pyrenoid matrix.The isolation method of chloroplasts and their pyrenoids was established, using the coenocytic green alga,Caulerpa, the chloroplasts of which have pyrenoids that contain chloroplast nucleoid DNA and Rubisco. It was revelaed that pyrenoid matrix is composed of six proteins, 97KDa, 63KDa, 54KDa 28KDa, 14KDa and DNA. In the supernatant which was gained from NaCl-treatment of pyrenoid fraction 54KDa, 14KDa and 44KDa proteins were present. The former two proteins correspond to the large and small subunits of Rubisco, respectively.