1993 Fiscal Year Final Research Report Summary
Studies on the Bacterial Stress Proteins as Virulence Factors
| Project/Area Number |
04670252
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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 |
細菌学
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| Research Institution | Kyorin University |
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Principal Investigator |
YAMAMOTO T. Kyorin Univ. Medicine, Associate Professor, 医学部, 助教授 (60110342)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI H. Kyorin Univ. Medidine, Research Assistant, 医学部, 助手 (40221650)
TAGUCHI H. Kyorin Univ. Medicine, Research Assistant, 医学部, 助手 (20146541)
OGATA S Kyorin Univ. Medicine, Professor, 医学部, 教授 (40086533)
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| Project Period (FY) |
1992 – 1993
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| Keywords | STRESS PROTEIN / VIRURENCE FACTOR / Yersinia enterocolitica / マクロファージ |
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| Research Abstract |
Yersinia enterrocolitica is a facultative intracellular pathogen capable of surviving within professional phagocytic cells. Since the internal environment is stressful for the phagocytosed bacteria, the bateria responds by induction of stress proteins which possibly contribute to intracellular survival. To identify the stress-responding genes important for intracellular survival, a total 1800 mutants of Y.enterrocolitica with independent Tn10-insertion were screened for the stress-sennsitive mutations that allow normal growth at 30ﾟC but either block or result in very poor bacterial growth at high temperature, 39ﾟC.The resulting 42 mutants with thermosensitive phenotype for vacterial growth were then screened for the mutation with a diminished capacity for intracellular survival using an in vitro asay for survival in macrophagges. A mutant named Gts 154 unable to survive within macrophages was less virulent than the wild-type parent in vivo. Theresult suggest the stress-responding gene at the stress envitonment in vitro involves in the survival and growth in the macrophage which is an imoportant aspect of virulence of Y.enterocolitica. We then studied a coordinate regulation in gene expression of Y.enterrocolitica which possibly contributes to bacterial survival within phagocytes. At least 16 proteins were selectively induced in response to phagocytosis. Several macrophage-induced proteins were also induced by heat shock and oxidative stresses in vitro. Of those, two major stress proteins, DnaK and CRPA, were immunologically identified. These results indicated that intracellular Y.enterocolitica exhibits a global stress respponse to the hostille environment of the macrophage.
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