1997 Fiscal Year Final Research Report Summary
Analysis of symbiosis among microbes forcused on a thermophilic symbiotic bacterium
| Project/Area Number |
08660121
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
応用微生物学・応用生物化学
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| Research Institution | Nihon University |
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Principal Investigator |
BEPPU Teruhiko Nihon Univ., Dept.Applied Biological Sciences, Professor, 生物資源科学部, 教授 (80011873)
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| Co-Investigator(Kenkyū-buntansha) |
UEDA Kenji Nihon Univ., Dept.Applied Biological Sciences, Assistant Professor., 生物資源科学部, 助手 (00277401)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Symbiobacterium thermophilum / Bacillus sp. / Symbiosis among microbes / tryptophanase / catabolite repression / ptsl / rumen bacterium |
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| Research Abstract |
We have analyzed the absolute symbiosis between symbiobacterium thermophilum (ST) and Bacillus strain S (BS) from the following two aspects.
(I) Possible involvement of ptsl gene of Bacillus in the symbiosis.
We have previously purified Ptsl protein from the cell extract of BS following its very weak growth-supporting activity for ST.We have performed expression and purification of recombinant Ptsl protein by E.coli system, and failed to detect it's ST-supporting activity. On the other hand, we have noticed that addition of glucose in the media completely inhibitted the growth of ST but not of BS, and further experiments showed that ptsl-deficient mutant supports the growth of ST even in the presence of glucose in the media. Therefore, we tentatively hypothesize that the growth supporting activity for ST by BS is under the control of catabolite repression, and ptsl is involved in the uptake of catabolites into the BS cells but not directly in the ST-supporting activity.
(II) Distribution of ST in the natural environment.
We have already postulated that ST exists widely in the natural habitat through our extensive screening. Simultaniously, we noticed that ST is frequently isolated from composts made from bovine excreta. Further results of screening with contents of digestive organs of several herbivorus animals showed the high possibillity that ST is one of rumen bactera. It agrees with the cellular and physiological features of ST.
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