Molecular and cell biological study on the heterogeneity of flagella in heterokont algae

异鞭毛藻的鞭毛一般长而短，长鞭毛上附着鞭毛体，短鞭毛上附着基部膨大部分，鞭毛的结构和功能有很大差异。本研究以金藻属的丹麦褐单胞菌（Ochromonas danica）和硅硅壳棕单胞菌（Ectocarpus siliculosus）为材料，研究了两种异鞭毛藻鞭毛的异质性，特别是鞭毛的伸长和分化过程。利用延时视频显微镜对褐单胞菌鞭毛复制进行了详细观察。电镜和免疫荧光显微镜观察到有丝分裂。赭色单胞菌的有丝分裂为开放纺锤形，根体位于两极，是鞭毛基体上的条纹结构。从使用各种抗体的研究中，我们发现，Ochromonas的根质体是由gannma微管蛋白，而不是centrin。这一结果表明，存在于各种真核藻类运动细胞中的根质体是不同源的，尤其是其组成蛋白。在电子显微镜下，我们研究了在游动孢子发生的多室zoidangia的Ectocarpus siliculosus鞭毛的伸长和分化的过程中，冷冻固定。两个鞭毛同时开始伸长，但我们可以通过直径和相关鞭毛根的差异来判断鞭毛的长或短。有趣的是，经常观察到从质膜向鞭毛膜添加小泡。附着的鞭毛体的长鞭毛不能观察到，虽然我们能够澄清的发展的基础肿胀部分的短鞭毛在哪里是由不同的材料。

Heterokont algae usually have a long flagellum attached with mastigonemes and a short one with the basal swelling part, and the structure and the function of these flagella are quite different. In this study, we studied the heterogeneity of two flagella in heterokont algae, especially focusing on the process of their elongation and differentiation using the chrysophycean alga Ochromonas danica and the brown alga Ectocarpus siliculosus. Flagellar duplication in Ochromonas was observed in detail by the time-lapse video microscopy. Moreover, mitosis was observed by electron and immunofluorescence microscopy. Mitosis of Ochromonas is the open spindle type, and the rhizoplast, which is the striated structure from the flagellar basal bodies, is located at both poles. From studies using various antibodies, we found that the rhizoplast of Ochromonas was composed of gannma-tubulin, not centrin. This result shows that the rhizoplast, which can be seen in motile cells in various eukaryotic algal groups, is not homologous, especially on its constituted proteins. In zoosporogenesis in the plurilocular zoidangia of Ectocarpus siliculosus, we examined the process of the flagellar elongation and differentiation using cryofixation under electron microscopy. Both flagella began to elongate simultaneously, while we could detect on which of the flagella is long or short by the difference of the diameter and the associated flagellar rootlets. Interestingly, addition of small vesicles to the flagellar membrane from the plasma membrane was frequently observed. Attachment of mastigonemes to the long flagellum could not be observed, although we were able to clarify the development of the basal swelling part of the short flagellum at where was composed of different materials.