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

异质藻鞭毛异质性的分子细胞生物学研究

基本信息

批准号：
17570047
负责人：
MOTOMURA Taizo
金额：
$ 2.37万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

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.

异鞭毛藻通常有一根附有鞭丝的长鞭毛和一根带有基部膨大部分的短鞭毛，这些鞭毛的结构和功能有很大不同。在本研究中，我们研究了异质藻中两种鞭毛的异质性，特别是利用金藻 Ochromonas danica 和褐藻 Ectocarpus siliculosus 来研究它们的伸长和分化过程。通过延时视频显微镜详细观察了 Ochromonas 中的鞭毛复制。此外，通过电子和免疫荧光显微镜观察有丝分裂。 Ochromonas 的有丝分裂是开放纺锤体型，根质体是鞭毛基体的条纹结构，位于两极。通过使用各种抗体的研究，我们发现Ochromonas的根质体由gannma-tubulin组成，而不是centrin。该结果表明，在各种真核藻类的运动细胞中可见的根质体不是同源的，特别是在其构成的蛋白质上。在 Ectocarpus siliculosus 的多眼zoidangia的游动孢子发生中，我们在电子显微镜下使用冷冻固定检查了鞭毛伸长和分化的过程。两条鞭毛同时开始伸长，同时我们可以通过直径和相关鞭毛细根的差异来检测哪条鞭毛长或短。有趣的是，经常观察到小囊泡从质膜添加到鞭毛膜上。尽管我们能够阐明短鞭毛的基部肿胀部分的发育，其中由不同的材料组成，但无法观察到鞭毛与长鞭毛的附着。