| Project/Area Number |
06670312
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Bacteriology (including Mycology)
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| Research Institution | University of Occupational and Environmental Health |
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Principal Investigator |
YOSHIDA Shin-ichi University of Occupatinal and Environmental Health, Microbiology, Professor, 医学部, 教授 (60128113)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAMOTO Hiroshi University of Occupatinal and Environmental Health, Microbiology, Assistant Prof, 医学部, 助手 (40229894)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Legionella / intracellular parasite / macrophage / cloning |
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| Research Abstract |
L.pneumophila Philadelphia-1 produced massive 24kDa protein during the intracellular growth in guinea pig macrophages. Using allelic exchange mutagenesis, a site-specific mutation was introduced into a gene encoding the 24kDa protein, and then we got a mutant UOEH strain. The mutant strain had a lower virulence than the parent strain to guinea pigs. Distribution of the gene among bacteria (7 species, 52 strains) was studied by Southern hybridazation. Only L.pneumophila had the 24kDa protein gene. These results suggest that the 24kDa protein is a virulence factor of L.pneumophila.
We found that one strain of Legionella dumoffii infected to Vero cells in vitro at a high rate. The L.dumoffii strain entered into Vero cells by receptor-mediated endocytosis which is inhibited by N-acetylglucosamine. It was found by electron microscopy that L.dumoffii lysed endosome membrane, escaped into cytoplasm and then proliferated there. These findings show a pleomorphism among Legionella species to enter into and proliferate in host cells.
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