1997 Fiscal Year Final Research Report Summary
Studies on the heme uptake system of a human pathogenic vibrio
| Project/Area Number |
08670307
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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 |
MIYOSHI Shin-ichi Okayama University, Graduate Shool of Natural Science & Technology Research Associate, 大学院・自然科学研究所, 助手 (60182060)
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| Co-Investigator(Kenkyū-buntansha) |
TOMOCHIKA Ken-ichi Okayama University, Faculty of Pharmaceutical Sciences Assistant Professor, 薬学部, 助教授 (00093691)
SHINODA Sumio Okayama University, Faculty of Pharmaceutical Sciences Professor, 薬学部, 教授 (50029782)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Pathogenic vibrio / Heme compound / Porphyrin |
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| Research Abstract |
Vibrio vulnificus, an opprtunistic human pathogen causing septicemia or wound infection, can obtain iron from a variety of heme proteins. This process involves the digestion of heme proteins by an exoprotease to leberate protoheme. In the present study, we investigated the protoheme uptake system of this human pathogenic vibrio.
1. In many human pathogens, protoheme is known to be fixed on the bacterial cell surface by the specific outer membrane receptor. Thus, we initially tested the presence of the protoheme receptor. The bacterium was found to express novel outer membrane proteins in the presence of protoheme. However, any of these proteins could not bind to protoheme, indicating V.vulnificus utilizes protoheme independent of the outer membrane receptor.
2. We isolated and characterized a mutant for protoheme utilization. One mutant isolated by treatment with a chemical mutagen was shown to be unable to use either protoheme or heme proteins, but multiplied in a medium supplemented with an iron-siderophore, uch as iron-vulnibactin. This finding demonstrates that V.vulnificus has the specialized protoheme uptake system.
3.V.vulnificus was found to utilize a synthetic heme compound (Fe-TPPS), as well as natural one(protoheme). The ability to utilize either heme compounds was competitively abolished by an excess amount of Cu-TPPS,an analog of the heme compound. Therefore, the protoheme uptake system in V.vulnificus may be not specific protoheme.
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