| Project/Area Number |
62560096
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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 |
発酵・醸造
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| Research Institution | University of Tsukuba |
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Principal Investigator |
SHOUN Hirofumi Institute of Applied Biochemistry, University of Tsukuba, 応用生物化学系, 助教授 (70012036)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1988: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1987: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | cytochrome P-450 / nitrate / nitrite-inducible / Fusarium / denitrification / モノオキシゲナーゼ / 硝酸誘導型 / 亜硝酸還元 |
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| Research Abstract |
(1) A semianaerobic culture of the cytochrome P-450(P-450)-producing fungus, Fusarium oxsporum, was shown to evolve nitrogen gas(N_2) then nitrite(or nitrate) was present in the culture medium. This process(denitrification) is now under investigation whether it is due to biological or non-biological reactions.
(2) In addition to P-450 cytochrome b_5 was isolated from F. oxysporum. It was shown that the fungus possesses an electron transport system similar to those in hepatic microsomes.
(3) The mechanism of induction of P-450 by nitrate(nitrite) was further studied. Addition of nitrate by the concentration as low as below l mM was sufficiently effective in inducing P-450 in the fungus. Other nitrogen sources such as ammonium or amino acids or sulfate were not effective. P-450 was induced on 1-2 days after addition of nitrate. The induction was not repressed by ammonium or other reduced nitrogen souces showing that the P-450 is not involved in the assimilatory metabolism of nitrate. On the other hand, the induction was inhibited by cycloheximide.
(4) Distribution of the nitrate-inducible P-450 among eukaryotic microorganisms was investigated. It was shown to be restricted to several species of Fusarium and Gibberella Fujikuroi. The cell-free extracts of these fungi contained intrate-inducible P-450 as well as substances that cross-react with the antibody against purified nitrate-inducible P-450.
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