| Project/Area Number |
14370090
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Nagoya University |
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Principal Investigator |
OHTA Michio Nagoya University, Graduate School of Medicine, Professor, 大学院・医学系研究科, 教授 (20111841)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Tadao Nagoya University, Graduate School of Medicine, Associate Professor, 大学院・医学系研究科, 助教授 (10314014)
TORII Keizo Nagoya University, University Hospital, Associate Professor, 医学部附属病院, 助教授 (80324440)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥11,200,000 (Direct Cost: ¥11,200,000)
Fiscal Year 2004: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2003: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 2002: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Keywords | Staphylococcus aureus / Streptococcus pyogenes / exoprotein / TSST-1 / agr / mga / Tat / signal peptidase / TAT蛋白 / スーパー抗原 / Bacillus cereus / ゲノム配列 / SEU / super antigen / カタボライトリプレッション / ETB / 環境因子 / 遺伝子ターゲッティング / 2成分制御系 / V8プロテアーゼ / 菌体外分泌蛋白 / アンチターミネーター |
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| Research Abstract |
We analyzed the mechanisms of the expression of exoproteins such as toxins and enzymes in Staphylococcus aureus and Streptococcus pyogenes. We performed comprehensive analyses of exoproteins of these bacteria by two dimensional gel electrophoresis (2-DE) and LC/MS/MS and constructed 2-DE maps. We detected putative genes that affect the expression of exoproteins in genome databases and constructed knockout mutants of these genes and analyzed the functions of these genes. The results were as follows.
Molecular epidemiological study for 23 exotoxin genes revealed that most Japanese MRSA strains were TSST-1,SEC3 and egc locus-positive, suggesting that these MRSA are very clonal. The differences of the expressed amount of each toxin were analyzed by 2-DE. We found that the expression of TSST-1 was very high in the strains that caused neonatal toxic shock-like exanthematous disease. The production of TSST-1 was suppressed by glucose-mediated catabolite repression. The difference of agr locus
… More
was not observed in theses trains.
We found that the expression of Sic protein was regulated by mga, a global regulator of S.pyogenes, since the production of Sic was reduced in an mga-knockout mutant, and that other several exoproteins were also regulated by mga.
It is very likely that the specific secretion machineries are involved in the expression of exoproteins in S.aureus and S.pyogenes, respectively. We found a tat-like gene similar to tat gene of Escherichia coli in the genome of S.aureus. We constructed tat-knockout mutants and found that the expression of several exoproteins were reduced in these mutants, suggesting that this tat-like gene is functional in S.aureus. Interestingly, fat-like gene was found in S.intermedius but not in other coagulase-negative staphylococci. These results suggested that Tat was involved in the virulence of staphylococci.
We detected four signal peptidase I (SPaseI)-like genes in the genome of S.pyogenes and constructed knockout mutants of sipC and spi genes. A sipC mutant reduced the expression of 54 exoproteins and a spi mutant reduced the expression of 36 exoproteins. We found preferential expression of some exoproteins in each mutant. Less
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