| Project/Area Number |
12680554
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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, SCHOOL OF PHARMA- CEUTICAL SCIENCES |
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Principal Investigator |
KATO Fumio Toho University, Pharma ceutical Sciences, Professor, 薬学部, 教授 (50057767)
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| Co-Investigator(Kenkyū-buntansha) |
TERADA Hiroshi National Institute of Public Health, Radiological Health, Researcher, 環境放射線学部, 研究員 (10260267)
SHIBATA Hisashi Yamanashi Forestry Forest Products Research Institute, Mycology, Researcher, 研究員
SUGIYAMA Hideo National Institute of Public Health, Radiological Health, Section Chief, 環境放射線学部, 室長 (00216350)
KUWAHARA Chikako Kanagawa Prefectural Public Health Laboratory, Radiological Health, Researcher, 生活環境部, 主任研究員
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | cesium / pH / Cs accumulation / soil / polyphosphate / potassium / キノコ生息土壌 / pH / セミウム取込 / 酸性土壌 |
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| Research Abstract |
We postulated that not only a direct transfer of ^<137>Cs form soil to mushrooms but also a food chain of ^<137>Cs from soil microorganisms to mushrooms would also contribute the high accumulation of ^<137>Cs in mushrooms. To confirm this hypothesis, we studied on physical characteristics of soils where wild mushrooms were grown, and microorganisms isolated from those soils. The pH of soils where mushrooms were grown were around pH 4.0-5.2. From the results, soil microorganisms were isolated on agar plates of pH5, 6 and 7. The number of bacteria isolated at pH6 was 1.6 times larger than that at pH7. Number of actinomycetes isolated from mushroom substrata was decreased with pH. Tolerance to Cs in the isolated microorganisms was measured. Most of the strains of actinomycetes were more sensitive to 10 mM Cs than those of bacteria. Effect of pH on tolerance to Cs was observed, that is, stronger growth inhibition by the same Cs concentration was observed at pH 5. The amount of Cs accumulated in those microorganisms was also affected by pH. SEM-EDX analysis of the microorganisms isolated from mushroom substrata showed that accumulated Cs was localized in a region being abundant in P, O and Cs. The elemental analysis suggested a participation of polyphosphate in the localization of Cs. We confirmed the presence of polyphosphate in Streptomyces lividans by ^<31>P-NMR. Interaction of polyphosphate with Cs will be elucidated by NMR experiments. Furthermore, we constructed a recombinant plasmid to disrupt the gene encoding polyphosphate kinase, and transformed the strains of actinomycetes. A strain whose ppk gene was disrupted, will indicate a new role of polyphosphate.
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