| Research Abstract |
Microsporidia are unicelluar amitochondriate protists and are parasitic to wide range of animals. This work was intended to explore a phylogenetic position of Microsporidia in the tree of eukaryotes by analyzing sequence data oftranslation related molecules. Genomic DNAs were ' obtained fiom three Microsporidians, Glugea plecoglossi (parasite of Ayu fish), Encephalitozoon cuaiculi, and E. hellem. Based on the PCR-based clonin, g method, genes putatively encoding valyl- and isoleucyl-tRNA synthetases, and mitochondrial-type heat shock protein 70 were sequenced. Genes for these molecules from other amitochondriate organisms, Giardia intestinalis, Trichomonas vaginalis, andlor Entamoeba histolytica were also sequenced when the data for these organisms were not available. Phylogenies of these molecules were individually examined. Then, a combined maximum likelihood analysis using all the molecules currently available in the database including these three was performed to examine a phylogenetic position of Microsporidia among enkaryotic major lineages. The result clearly demonstrated that Microsporidia are not early branching enkaryotes, but are closely related to fungi and that Microsporidia secondarily lost mitochondria during their evolutionary past. In addition, in order to construct a system for analyzing ribosomal proteins of Microsporidia in the filture, ribosomal proteins of other amitochondriate organisms, Giardia intestinalis. Trichomonas vaginalis, and Mastigamoeba balamuthi were purified and preliminary analyzed by the use of two-dimensional electrophores is.
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