| Project/Area Number |
17580059
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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 |
Applied microbiology
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
SATO Tsutomu Tokyo University of Agriculture and Technology, Institute of Symbiotic Science and Technology, Associate Professor, 大学院共生科学技術研究院, 助教授 (70215812)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | bacteria / Bacillus subtilis / cellular differentiation / cell death / respiration |
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| Research Abstract |
The timing of spore maturation is coordinated by continuous close collaboration between two cells, the mother cell and forespore in Bacillus subtilis. We have identified the following events during the late stage in the mother cell : spore detachment from the polar site of the mother cell, membrane rupture, cell wall collapse, and release of the free spore. The membrane rupture was followed by mother cell lysis. The ability to sporulate depends on the availability of sufficient energy reserves to complete the developmental process, and this energy source may run out in the mother cell at the time of spore maturation. The timing of mother cell death might be determined by the level of energy reserves at the initiation of sporulation. In the course of our studies of the mother cell death in B. subtilis, we have focused on NADH dehydrogenase, which catalyzes the oxidation of NADH by transferring electrons to ubiquinone and establishes a proton motive force across the cell membrane. The yjlD (renamed ndh) gene of B.subtilis is predicted to encode an enzyme similar to the NADH dehydrogenaseII of Escherichia coli, encoded by the ndh gene. We have shown that the yj1C-ndh operon is negatively regulated by YdiH (renamed Rex). The ndh gene regulates expression of the yj1C-ndh operon, as indicated by the fact that mutation in ndh causes a higher NADH/NAD ratio. An in vitro study showed that Rex binds to the downstream region of the yj1C-ndh promoter and that NAD enhances the binding of Rex to the putative Rex-binding sites in the yj1C-ndh operon as well as in the cydABCD operon. These results indicated that Rex and Ndh together form a regulatory loop which functions to prevent a large fluctuation in the NADH/NAD ratio in B.subtilis.
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