| Project/Area Number |
16406013
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Bacteriology (including Mycology)
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| Research Institution | Osaka Prefecture University (2005)
Okayama University (2004) |
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Principal Investigator |
KURAZONO Hisao Osaka Prefecture University, Dept. of Veterinary Medicine, Professor, 生命環境科学研究科, 教授 (90186487)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAYAMA Toshiya Nagasaki University, Institute for Tropical Medicine, Professor, 熱帯医学研究所, 教授 (50050696)
MAKINO Souichi Obihiro University, Center for Animal Hygiene and Food Safety, Professor, 大動物特殊疾病研究センター, 教授 (30181621)
HOSHI Hidenobu Osaka Prefecture University, Dept. of Veterinary Medicine, Research Associate, 生命環境科学研究科, 助手 (30301188)
木村 美幸 岡山大学, 医学部, 助手 (60346418)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥11,300,000 (Direct Cost: ¥11,300,000)
Fiscal Year 2005: ¥5,500,000 (Direct Cost: ¥5,500,000)
Fiscal Year 2004: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | Southeast Asia / Bacteria / Intestinal Infection / Virulence factor / Epidemiology / 腸管感染症 |
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| Research Abstract |
A gene encoding the resuscitation-promoting factor (Rpf) from Salmonella Typhimurium LT2 was cloned and characterized. The S.Typhimurium LT2 rpf gene is 696 bp long, and shared a conserved segment with Salmonella enterica serovar Oranienburg (99.4%). The rRpf not only promoted proliferation but also induced resuscitation of VNC (viable but non-culturable) cells to the culturable state in a dose-dependent manner. Therefore, rRpf may be useful for detection of bacterial contaminants present in the VNC form in food samples and the environment (Panutdaporn N. et al, Int.J.Food Microbiol. 106 : 241-247, 2006).
In an enterohemorrhagic Escherichia coli (EHEC) O157:H7 outbreak caused by salted salmon roe that occurred in Japan, 1998, a food isolate (F2) was NaCl-resistant and a patient isolate (P5) was sensitive to NaCl. Hydrogen peroxidase, like NaCl, induced a significant loss of culturability in P5. The BacLight assay suggested that the EHEC O157:H7 entered a viable but non-culturable (VNC) state. Mouse-passaged isogenic variants of F2 became NaCl- and oxidation-sensitive, entered the non-culturable state in response to either of these stresses, and could be resuscitated by sodium pyruvate. In vivo passage negatively modulated RpoS expression, and the subsequent stress exposure induced the VNA state in the EHEC O157:H7 isolates (Asakura H. et al, FEMS Microbiol.Lett. 253 : 243-249, 2005).
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