花粉中的收缩蛋白与细胞质流动

THE PRESENCE OF CONTRACTILE PROTEINS IN POLLENS AND THEIR ROLE IN CYTOPLASMIC STREAMING

从植物的花粉中提取得到了肌球蛋白和肌动蛋白。用4—30%SDS 梯度聚丙烯酰胺凝胶电泳测定丝瓜花粉肌球蛋白重链的分子量为165kD。花粉肌球蛋白的 ATP 酶活性与兔肌肌球蛋白 ATP 酶活性具有一致的特征,即在0.5mol/l KCl 的条件下,其 K^+-EDTA ATP 酶活性最高,Ca^(2+)-ATP 酶活性次之,Mg^(2+)-ATP 酶活性最低。用 SDS 制备型聚丙烯酰胺凝胶电泳的方法,制备得到了电泳纯的玉米花粉肌动蛋白,用 SDS 聚丙烯酰胺凝胶电泳测定了肌动蛋白的分子量,结果表明,花粉肌动蛋白与兔肌肌动蛋白具有相同的分子量(43kD)。药物处理表明,细胞松弛素 B、氯丙嗪和氯四环素对花粉管细胞质流动均有抑制作用。而秋水仙碱对细胞质流动没有抑制作用。对肌球蛋白和肌动蛋白在花粉管细胞质流动中所起的作用进行了讨论。

Authors demonstrate the presence of actin and myosin in pollens from Luffa cylindrica and Zea mays in this report The molecular weight of the heavy chain of pollen myosin is about 165000 daltons as analyzed by 4—30% SDS gradient polyacrylamide gel electrophore- sis The ATPase activity of pollen myosin is identical with the characteristics of rabbit ske- letal muscle myosin.In 0.5 mol/l KCl,the K^+-EDTA activity is the highest and Mg^(2+)activity the lowest.The Ca^(2+)activity is higher than Mg^(2+)activity and lower than K^+-EDTA activity. Pollen actin from Zea may,was prepared by preparative SDS polyacrylamide gel electrophore- sis.Its molecular weigh,iS 43,000 daltons which is the same as rabbit skeletal muscle actin. The effect ot drugs on cytoplasmic streaming of pollen tubes were observed under optical microscope Cytochalasin B (CB),chloropromazine (CPZ) and chlorotetracycline (CTC) inhibit cytoplasmic streaming obviously.But colchicine has no effect on the cytoplasmic stream- ing.It is suggested that the motive force of cytoplasmic streaming may be the interaction of myosin and actin in the pollen tubes.