Studies on the mechanism of cytokinesis in higher plant cells

烟草培养细胞的细胞周期进程高度同步，获得具有植物细胞动力学装置——膜质体的细胞。利用这些细胞或从这些细胞中分离出来的膜质体，我们得到了以下结果：在后期/末期从烟草细胞中分离出的膜质体的微管与许多小囊泡相关，但当膜质体从先前已导入ATP的细胞中分离出来时，膜质体微管仅与少量囊泡相关，这表明膜质体微管与小囊泡的关联是ATP依赖的。用荧光染料标记动物脑微管蛋白，并将其引入具有片质体的质膜渗透烟草细胞。荧光首先在膜质体的赤道区被观察到，表明膜质体微管在其正端被聚合。当用未标记的微管蛋白进一步处理细胞时，赤道区的荧光带分裂为两条，表明聚合微管的易位与聚合同时发生。膜质体微管的易位是GTP依赖性的。分离的膜质体赤道区具有将UDP-葡萄糖转化为- 1,3 -葡聚糖的活性。

Progression of the cell cycle of tobacco cultured cells was highly synchronize to obtain cells having the phragmoplast, the cytokinetic apparatus of plant cells. Using such cells or phragmoplasts isolated from such cells, we obtained following results.1. Microtubules of phragmoplasts isolated from tobaccou cells at anaphase/telophase were associated with many small vesicles, but when phragmoplasts were isolated from cells, into which ATP had previously been introduced, phragmoplast microtubules were associated with only small numbers of vesicles,suggesting that the association of small vesicles with phragmoplast microtubules is ATP dependent.2. Animal brain tubulin was labeled with fluorescent dye and was introduced into plasma membrane permeabilized tobacco cells having phragmoplasts. Fluorescence was first oserved at the equatorial region of the phragmoplast, indicating that phragmoplast microtubules are polymerized at their plus ends. The fluorescent band at the equatorial region was split into two when the cells were further treated with unlabeled tubulin, suggesting that the translocation of polymerized microtubules occurs concomitantly with the polymerization. The translocation of phragmoplast microtubules was found to be GTP dependent.3. The equatorial regions of isolated phragmoplasts showed the activity to incorporate glucose from UDP- glucose into beta-1, 3-glucan.