| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
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.
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