2013 Fiscal Year Final Research Report
Investigation of the regulatory mechanism for the production of a human specific cytolysin, a crucial factor for the infectivity of Streptococcus intermedius
| Project/Area Number |
23590510
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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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 |
TOMOYASU Toshifumi 徳島大学, ソシオテクノサイエンス研究部, 准教授 (20323404)
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| Co-Investigator(Kenkyū-buntansha) |
TABATA Atushi 徳島大学, 大学院ソシオテクノサイエンス研究部, 助教 (10432767)
NAGAMUNE Hideaki 徳島大学, 大学院ソシオテクノサイエンス研究部, 教授 (40189163)
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| Project Period (FY) |
2011 – 2013
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| Keywords | 連鎖球菌 / 細胞溶解毒素 / 発現制御 / 細胞毒性 / ガラクトース |
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| Research Abstract |
Streptococcus intermedius secretes intermedilysin(ILY), which is a major virulence factor of this pathogen. We showed that the disruption of lacR in an ILY low-producing strain (PC574) led to higher hemolytic activity, increased transcription of ily and higher cytotoxicity against HepG2 cells, when compared to the parental strain. The direct binding of LacR within the ily promoter region was observed by a DNA probe pull-down assay. Adding galactose or lactose into the medium increased the amount of ILY secreted by PC574 cells.
Furthermore, we studied the lacR nucleotide sequences and the hemolytic activity of 50 strains isolated from clinical infections and 7 strains isolated from dental plaque. Thirteen strains isolated from clinical infections showed high ILY production and 9 strains had one or more point mutations and/or an insertion mutation in LacR, which caused the decline in its function.
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Research Products
(11 results)
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[Journal Article] LacR mutations are frequently observed in Streptococcus intermedius and are responsible for increased intermedilysin production and virulence2013
Author(s)
Tomoyasu T, Imaki H, Masuda S, Okamoto A, Kim HJ, Waite RD, Whiley RA, Kikuchi K, Hiramatsu K, Tabata A, Nagamune H
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Journal Title
Infect. Immun
Volume: 81(9)
Pages: 3276-3286
DOI
Peer Reviewed
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