| Project/Area Number |
16590360
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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 |
Bacteriology (including Mycology)
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
OKAMOTO Keinosuke Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Professor, 大学院・医歯薬学総合研究科, 教授 (70131183)
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| Co-Investigator(Kenkyū-buntansha) |
MIYOSHI Shin-ichi Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Professor, 大学院・医歯薬学総合研究科, 教授 (60182060)
NAKAO Hiroshi Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Associate Professor, 大学院・医歯薬学総合研究科, 助教授 (20237217)
YAMANAKA Hiroyasu Hiroshima International University, Faculty of Pharmaceutical Sciences, Professor, 薬学部, 教授 (30202386)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Bacteria / Aeromonas / Protease / Chaperone / Escherichia coli / Enterotoxin / Secretion apparatus / Pathogenicity / 溶血毒 / フーリン / 下痢 / 基質 / タンパク毒素 / 成熟化 / 溶血毒素 / 外膜蛋白質 |
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| Research Abstract |
Bacterial pathogenicity of bacteria is often determined by the exotoxins produced from the bacteria. The loss of the ability to produce these toxins leads to the loss of pathogenicity. These extoxins are protein. The protein just synthesized in cytoplasm is a string composed of amino acid residues. In the process to become mature (bio-active) protein, many bacterial factors and apparatus are involved. If the bacteria lose the ability to produce these factors and apparatus, the bacteria cannot produce exotoxins. This leads the conversion of pathogenic bacteria to non-pathogenic bacteria. In addition, the compounds to inhibit the maturation process of proteintoxin might be unique and good medicine for these pathogenic bacteria. From this view point, the studies reported here were performed. The subjects treated in this experiments were serine protease of Aeromonas and heat-stable enterotoxin (ST) of Escherichia coli. The studies revealed the following points. The serine protease of Aerom
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onas requires the dependent chaperone protein to become mature toxin. The requirement of dependent chaperone protein for the maturation is rare in bacterial proteases. The subsequent studies showed that the association of the chaperone protein with the serine protease is achieved in periplasmic space. The mutation experiments suggested that the carboxy terminal regions of both proteins, chaperone and serine protease, are important for the association. The inhibition of the association might results in the loss of serine protease production for Aeromonas. The studies about the secretion of ST revealed the following points. An outer membrane protein, TolC, is utilized in the secretion of ST. Almost gram-negative bacteria possess TolC, however, the amino acid sequences of these TolCs slightly differ each other among these TolCs. To clear the relationship between the difference and its host strain, we expressed tolC gene of Vibrio parahaemolyticus in Escherichia coli and measured tits activity. The results showed that TolC of V.parahemolyticus expressed in is functional when it interacts with AcrAB, which is a apparatus for secretion located in inner membrane, however, TolC of V.parahemolyticus cannot cooperate with other secretion apparatuses in inner membrane of E.coli Of course, TolC of E.coli can cooperate with these secretion apparatuses. The amino acid residues, which are not common to sequences of both TolCs, may be important in the binding for TolC with these secretion apparatuses. Less
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