1997 Fiscal Year Final Research Report Summary
Study on the activation mechanism of the spore-lytic enzyme (s) during germination of Bacillus cereus spores.
| Project/Area Number |
08660103
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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 | Nagoya University |
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Principal Investigator |
MORIYAMA Ryuichi Nagoya University, Department of Applied Biological Sciences, Associated Professor, 農学部, 助教授 (60191061)
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| Project Period (FY) |
1996 – 1997
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| Keywords | bacterial spores / cortex-lytic enzyme (s) / germination |
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| Research Abstract |
1. Enzymes (SleB) that hydrolyze spore cortex during germination of Bacillus cereus and Bacillus subtilis spores were identified and corresponding genes (sleB) were cloned.
2. Expression of wild-type and mutant SleB of B.cereus in Escherichia coli revealed that the unique cysteine residue at C-terminal portion SleB is functionally important for its enzymatic activity.
3. Deletion of sleB significantly affected the L-alanine-mediated germination process of B.subtilis spores, indicating the enzyme corresponds to the universal germinant, L-alanine.
4. Novel subtilisin-like protease was purified from B.cereus spores and characterized. The protease binds to the surface of spores electrostatically, but loss of enzyme from spores did not affect spore germination, indicating that the protease is not involved in the germination process. However, the protease is unique in its high specific activity and sensitivity to SH-reagents, such as HgCl_2. Cloning of the gene encoding the protease revealed the enzyme is categorized into subfamily of subtilisin.
5. Antimicrobial activities of sucrose monoalkylates (sugar ester, SE) were examined. SEs bind to the surface of B.cereus spores, and numbers of binding seems to relate to the antimicrobial activity of SE.Loss of the antimicrobial activity of SE during spore germination was revealed to be caused through the lysis of SE by esterase released from spores.
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