| Project/Area Number |
13680634
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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 |
環境影響評価(含放射線生物学)
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| Research Institution | Toho University |
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Principal Investigator |
KATO Naoyuki TOHO UNIVERSITY, SCHOOL OF MEDICINE, ASSOCIATE PROFESSER, 医学部, 助教授 (50104154)
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| Co-Investigator(Kenkyū-buntansha) |
OHNO Akira TOHO UNIVERSITY, SCHOOL OF MEDICINE, ASISTENT PROFESSER, 医学部, 助手 (40223903)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2001: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | LEGIONELLA / HOT SPRING / VIABLE BUT NONCULTURABLE / L.PNEUMOPHILA / ACANTHAMOEBA / CHLORINE STERILIZATION / ELCIDATION OF CONTAMINATION ROUTE / SOIL / PFGE法 / 残留塩素濃度 / L. pneumophila / PCR法 / RAPD法 / 血清群 / レジオネラ / pH / 温度 / 電導度 |
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| Research Abstract |
1.Change in the quality due to chloridizing against sampled water collected from indoor or outdoor bathtub of various spa was analyzed and epidemiological study of Legionella spp. in these water was carried out.
2.Transition to VNC (viable but not cultivable) stage of L.pneumophila population in microcosms preparated in sampled water was examined under conditions of different pH and temperature
(1)Whole cells of L.pneumophila were killed in a short period in microcosm with extreme low pH, while cell numbers were gradually reduced in microcosm with high pH. On the other hand, it was suggested that cell population in microcosm with pH5 shifted to VNC stage. (2)L.pneumophila could survive for a long period in microcosms in a range of pH6.0 to 8.2 or 25 to 42℃ (3)It has previously been thought that L.pneumophila could not survive in high-temperature water of 45℃ however, the present data suggested that L.pneumophila could survive as VNC even under this condition. However, L.pneumophila was q
… More
uickly killed in microcosms with temperature of 50 or more degrees Celsius.
3.Antiseptic effect of chlorine against L.pneumophila and Acanthamoeba was examined.
(1)L.pneumophila could survive for one minute or more in microcosm with 0.4 ppm of residual chlorine. In residual chlorine of 1.0 ppm, the organisms were quickly killed. (2)Acanthamoeba cells were added into microcosms, and then L.pneumophila multiplicated in phagosomes of amoeba cells and ate away cells, and repeated these process during incubation. After incubation for 24 hrs, a various concentrations of chlorine were added into microcosms. A small amount of L.pneumonia cells was detected even in microcosm disinfected with 50 ppm of residual chlorine. Forty % of Acanthamoeba cells was living in microcosm with 10 ppm of residual chlorine. These cells might exsist as cyst cell having resistance to chlorine, therefore, L.pneumonia cells were also protected in these cysts from bactericidal effect of chlorine.
4.The route that Legionella contaminate spa was studied.
(1)Genotype of L.pneumophila isolates with identical serotype isolated from spa and the surrounding soil was determined by randomly amplified polymorphic DNA analysis(RAPD). As so far examined, genetic identity among these isoltes was not recognized. (2)RAPD analysis was done about L.pneumophila isolates of a variety of serotype isolated from bathtub and filtlate tank in spa with circulating system. Genetic identity was shown among isolates of different serotype. Further confirmation by pulse field gell electrophoresis(PFGE) was carried out. Less
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