| Project/Area Number |
11660315
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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 Tropical Biosphere Research Center, University of the Ryukyus, Professor, 熱帯生物圏研究センター, 教授 (00039926)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Bdellovibrio / Vibrio parahaemolyticus / seafood / lytic spectrum / カキ / エビ / 保存温度 / 型別 / 海水 / 漁港 |
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| Research Abstract |
One of the difficult problems in the epidemiological survey to identify the causative food of an outbreak of Vibrio parahaemolyticus-gastroenteritis is that thermostable direct hemolysin (TDH) -producing strains of V.parahaemolyticus could not be detected from marine products suspected to be causative foods in many cases. I supposed that seafood would be contaminated with bdellovibrios as well as TDH-producing strains at the coastal areas including fishing ports and fishing farms and that TDH-producing strains had been killed by the infection of bdellovibrios before the epidemiological survey.
We detected 125 strains of Bdellovibrio to lyse V.parahaemolyticus strains from the seawater at Toguchi Port in Motobu-cho, Okinawa Prefecture. Lytic spectra of the isolated 114 Bdellovibrio strains to 15 TDH producing V.parahaemolyticus strains were categorized to 56 types. Lytic activity of Bdellovibrio strain Cd22 to V.parahaemolyticus strain D3 was stable in artificial seawater with a salinity of 35-10‰ but not stable in the seawater with a salinity of 5‰ or less, suggesting that the bdellovibrio strain would be marine bacterium and that it could not lyse V.parahaemolyticus unstable at estuaries. Concentrations of strain D3 to support the growth of Bdellovibrio strain Yd9-1 was 10^8 cfu/ml or more. When shrimp (Penaeus monodon) was contaminated with strains D3 and Yd9-1 and kept in 5℃, strain D3 decreased to 10% or less within 4 days compared with samples without Yd9-1. These evidences suggest that V.parahaemolyticus strains contaminated to the seafood would be killed by the infection of bdellovibrios at the storage in the refrigerator.
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