| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
It has long been believed that there are discrete differences between prokaryotic and eukaryotic ribosomes in both function and structure. These facts have influenced on the concept that eukaryotes emerged as a result of fusion of two kinds of prokaryotic cells. Recently, it has been reported that some parasitic procysts possessed ribosomes with sedimentation coefficient similar to prokaryotic ribosomes. This project aimed to elucidate the origin of eukaryote by analyzing the function of the prokaryotic ribosomes from the eukaryotes.
Ribosomal fraction and other soluble enzyme fractions were prepared from microsporidia Nosema bombycis whose ribosome has a sedimentation coefficient of 70S.Ribosomes from rat liver and Escherichia coli were also prepared for comparison.
With ATP regeneration system, ribosomes from E.coli and rat liver were actively incorporatelabeled phenylalanine depending exogenously added poly(U).Ribosomes from N.bombycis, however, incorporated little, if any, labeled amino acids in any of the system examined.
Alteration of cell disrupting or cell fractionation methods failed to improve the activity of the system. We now conclude that the material, i. e., dormant spores of N.bombycis, is not suitable for the source of biologically active ribosomes.
During the course of this study, we cloned some genes including HSP7O gene from N.bombycis genome. The sequence analysis revealed that N.bom bycis which does not have mito-chondria lost mitochondria secondarily during the evolution of the organism.
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