2002 Fiscal Year Final Research Report Summary
Ecological mechanism to restrict the main prevalence area of Vibrio parahaemolyticus to estuaries
| Project/Area Number |
13660321
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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 |
Applied veterinary science
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
KUMAZAWA Norichika University of the Ryukyus, assistant, 熱帯生物圏研究センター, 教授 (00039926)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Bdellovibrio / Vibrio parahaemolyticus / food poisoning / estuary / fishing port |
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| Research Abstract |
There are many cases that TDH-producing stains of Vibrio parahaemolyticus are not detected from seafood suspected to the cause of gastroenteritis. The suspected seafood might be contaminated with bdellovibrios in addition to TDH-producing strains. I detected bdellovibrios from water at 3 estuaries; Kanita estuary in Aomori, Miwatari estuary in Mie and Urado estuary in Kochi, and 3 fishing ports; Matsugasaki port in Mie, Murotsu port in Kochi and Toguchi port in Okinawa. PCR product (about 1,500 bp) was obtained from strain Ao1 isolated from Kanita river using primers 8-27 and 1492R of 16S ribosomal RNA gene of eubacteria. Base sequence of 1059 bp of the PCR product showed 92% homologous with 16S ribosomal RNA gene of Bdellovibrio sp. So strain Ao1 was suspected to be Bdellovibrio sp.
Seasonal variations of bdellovibrios and V. parahaemolyticus have been examined in water at Toguchi, Murotsu and Matsugasaki ports. At Toguchi port, bdellovibrios were detected intermittently at a level of 10^2 to 10^4/l from September 2001 to September 2002 but not detected from October 2002 to February 2003. Levels of bdellovibrios were high when levels of V. parahaemolyticus were low. At Matsugasaki port, bdellovibrios were detected intermittently at a level of 10^4/l since November 2001 though the relationship between the level of bdellovibrios and that of V. parahaemolyticus was not clear. At Murotsu port, bdellovibrios were detected at a level of 10^3 to 10^5/l continuously from September 2001 to January 2003 though the relationship between the level of bdellovibrios and that of V. parahaemolyticus was not clear. As there is no estuary for V. parahaemolyticus can survive at high levels near Murotsu port, bdellovibrios might grow in marine vibrios other than V. parahaemolyticus there.
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