| Project/Area Number |
06640844
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
ARATA Hiroyuki Kyushu University, Faculty of Science, Research associate, 理学部, 助手 (80151166)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIMURA Mitsuo Kyushu University, Faculty of Science, Professor, 理学部, 教授 (40037255)
SHIMAZAKI Kenichiro Kyushu University, Faculty of Science, Professor, 理学部, 教授 (00124347)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Crassulacean Acid Metabolism / Vacuole / Circadian Rhythm / Ion Channel / Malic Enzyme / 慨日リズム |
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| Research Abstract |
We investigated if regulations of translocation and decarboxylation of malate are involved in the generation of the endogenous rhythm of crassulacean acid metabolism.
1. CAM plants evolve oxygen in the absence of external CO_2 as a result of photosynthesis using malate stored in vacuoles as the carbon source. The malate-dependent photosynthesis exhibited diurnal rhythm and the rhythm persisted under continuous light conditions. The results indicate that the endogenous clock regulates the translocation of malate across the vacuolar membrane and/or decarboxylatin of malate.
Activity of cytoplasmic NADP-malic enzyme in leaf extract showed diurnal rhythm. The rhythm, however, did not correspond to the rhythm of malate-dependent photosynthesis, or did not persist under continuous light conditins. This enzyme did not seem to be regulated by the endogenous clock.
Mitochondrial NAD-malic enzyme in leaf extract did not show rhythmic change in its activity or in its quaternaly structure. The possibility remained is that the enzyme is regulated by concentration of effectors such as CoA or Mn^<2+> in the mitochondria.
We have not characterized the malate channels in the vacuolar membrane. Characterization of the channels will reveal the mechanisms for the formation of the circadian rhyth of in malate remobilization.
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