1994 Fiscal Year Final Research Report Summary
Mechanism of expression of protease activity synchronized with beginning of chloroplast division.
| Project/Area Number |
05804049
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物生理
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| Research Institution | Toyama University |
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Principal Investigator |
INOUE Hiroshi Toyama Univ., Fac.Science, Professor, 理学部, 教授 (50109097)
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| Co-Investigator(Kenkyū-buntansha) |
KAMACHI Hiroyuki Toyama Univ., Fac.Science, Assistant, 理学部, 助手 (40262498)
YOSHIHIRA Takashi Toyama Univ., Fac.Science, Assistant, 理学部, 助手 (50242475)
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| Project Period (FY) |
1993 – 1994
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| Keywords | spore germination / fern / Osmunda japonica / chloroplast / protease / protein degradation |
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| Research Abstract |
The comparison of polypeptide compositon of chloroplasts during spore germination was investigated in green spores of the fern Osmunda japonica. The maximal germination was attained after 38 h from imbibition. Cycloheximide inhibited the spore germination. The polypeptide composition of chloroplasts was remarkably changed by spore germination for 48 h. Five polypeptides with apparent molecular weights of 47.44,42,22 and 18.5 kDa in the soluble fraction of chloroplasts and three polypeptides with molecular weights of 24,22 and 15 kDa in the thylakoid membranes were reduced during germination. In contrast, no remarkable disappearance of chloroplast polypeptides was observed in the spores incubated with cycloheximide for 48 h. A new protein was isolated from thylakoid membranes of spores and purified. This protein with a native molecular mass of 80 kDa was characterized by a subunit band observed at a molecular weight of 22 kDa on SDS-PAGE and by the disappearance of the band during spore germination. High levels of alanine and glycine were found in the basic protein (pl>10.3). Protease activity against the 22 kDa-protein was observed in chloroplasts of quiescent spores. Results indicate that a cytosolic proteinous factor in an early step of germination may be common with regulatory factors in chloroplast division and degradation of chloroplast protein.
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