2004 Fiscal Year Final Research Report Summary
Analysis of infectious factors of Bacteroides fragilis in the compromised host
| Project/Area Number |
15590389
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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 | The University of Tokushima |
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Principal Investigator |
OHNISHI Yoshinari The University of Tokushima, Institute of Health Biosciences, Department of Molecular Bacteriology, Professor, 大学院・ヘルスバイオサイエンス研究部, 教授 (10037400)
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| Co-Investigator(Kenkyū-buntansha) |
KUWAHARA Tomomi The University of Tokushima, Institute of Health Biosciences, Department of Molecular Bacteriology, Associate professor, 大学院・ヘルスバイオサイエンス研究部, 助教授 (60263810)
KATAOKA Keiko The University of Tokushima, Institute of Health Biosciences, Department of Molecular Bacteriology, Assistant professor, 大学院・ヘルスバイオサイエンス研究部, 講師 (40189303)
NAKAYAMA Haruyuki The University of Tokushima, Institute of Health Biosciences, Department of Molecular Bacteriology, Research associate, 大学院・ヘルスバイオサイエンス研究部, 助手 (80294669)
ARIMOCHI Hideki The University of Tokushima, Institute of Health Biosciences, Department of Molecular Bacteriology, Research associate, 大学院・ヘルスバイオサイエンス研究部, 助手 (30311822)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Bacteroides fragilis / Genomic analysis / Glycosyl hydrolases / Sialoglycoconjugates / Sepsis / Compromised host / Restriction-modification system / DNA inversion |
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| Research Abstract |
Genomic analysis of Bacteroides fragilis strain YCH46 revealed that this strain has acquired an exceptionally high capability to utilize polysaccharides through extensive amplification of the genes involved in polysaccharide binding, degradation and transport. The expression of genes involving in the synthesis of surface architectures, such as capsular polysaccharides and outer membrane proteins are regulated in an on-off switching through reversible DNA inversions of promoters. We identified a unique 27-kb gene cluster, designated as sgu (sialoglycoconjugate utilization) gene cluster, which consists of 13 genes responsible for the uptake and degradation of sialoglycoconjugates and is located on the region downstream of the sialidase gene (nanH3) in B. fragilis strain YCH46. PCR analysis demonstrated that almost all of the regions in the sgu gene cluster were conserved among the B. fragilis strains tested. Results of transcriptional analysis enabled classification of the genes in the sgu cluster into three regulatory units on the basis of expression patterns in response to various kinds of carbon sources. A mouse model of intraabdominal abscess formation revealed that nanH3, estA, and estS in the sgu gene cluster were thought to play an important role on abscess formation of B. fragilis. The restriction barrier of B. fragilis could be overcome by methylation of plasmid DNA in vitro with a cell-free extract from the homologous strain.
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