1994 Fiscal Year Final Research Report Summary
Purification and Physiological role of the adenylate cyclase in Dunaliella
| Project/Area Number |
05640737
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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 | Toho University |
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Principal Investigator |
OKADA Mitsumasa Toho University, Dept.Biomol.Sci., Professor, 理学部・生物分子科学科, 教授 (80057629)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Adenylate cyclase / Dunaliella / Salt tolerance |
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| Research Abstract |
1) Growth and Photosynthetic activity in Dunaliella under stress.
Signal transduction system including adenylate cyclase (AC) is supposed to be responsible for some metabolic changes in Dunaliella. The alga showed following changes according to salt stress, aging and high light.
・In the medium containing 10% NaCl, the maximum growth was observed in ten days. In that containing 25% NaCl, slow growth was observed during 30 days. Maximum cell numbers per ml of medium was about 20 times larger in the former medium.
・During aging, decrease of chlorophyll content and accumulation of carotenoids, especiaslly beta-carotenoids were obseved.
・Chlorophyll a/b ratio increased from 1.8 to 3.5 when light-intensity for the culture increased. The change of the efficincy for the energy transfer from carotenoids and chl b to chl a was also observed.
2) AC in Dunaliella showed remarkable affected by divalent cations. No activity was observed in the absence of Mg and the activity was fully enhanced at 5mM of Mg. Ca showed strong inhibition and 50% inhibition occurred at 50-100uM.
3) Membrane fraction was treated by 1M NaCl, and solubilized AC was purified by gel filtration followed by ion change chromatography. Molecular wight of whole enzyme was 452kDa and that of the subunit was estimated 116kDa by SDS-PAGE.
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