| Project/Area Number |
17390173
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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 | 一般 |
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| Research Field |
Hygiene
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| Research Institution | Okayama University |
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Principal Investigator |
WANG Da-hong Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Dentistry Sciences Assistant Professor (90294404)
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| Co-Investigator(Kenkyū-buntansha) |
TSUTSUI Ken Okayama University, Advanced Science Research Center, Professor (70108158)
SANO Kuniaki Okayama University, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Assistant Professor (00294405)
MASUOKA Noriyoshi Okayama University of Science, Department of Life Science, Professor (20116502)
ITO Takehiko Okayama University, Faculty of Education, Professor (10291973)
OGINO Keiki Okayama University, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Dentistry Sciences, Professor (70204104)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥7,520,000 (Direct Cost: ¥7,100,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2005: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | Catalase mutant gene / Transformants / CAT assay / Chemical compounds / Risk assessment / Oxidative stress / Antioxidants / Screening / ジチオトレイトール / 過酸化水素 / ローソン / ヘンナ製品 / ヒドロキノン / クメンハイドロペルオキサイド / 浸出水と放流水 |
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| Research Abstract |
This research aimed at developing a screening method for hazard identification using catalase mutant E coli strains constructed by encoding the catalase cDNA from catalase mutant mice (Cs^b) and its corresponding wild type (Cs^a) into catalase-deficient K coli UM255. To assess the cytotoxicity of the chemicals, we employed a CAT assay (a zone of inhibition test of bacterial growth and colony-forming efficiency test using catalase mutant E coli strains). Lawsone exposure inhibited the growth of both Cs^a and Cs^b strains in a dose-dependent manner, in which Cs^b was more susceptible than Cs^a, showing the larger zone of growth inhibition surrounding the paper disc. Natural henna leaves did not show toxic effects, whereas two out of four samples of market henna products were shown toxicity effects. Catalase abolished zone of inhibition of henna products, and low concentration of exogenous MnSOD and Cu/ZnSOD eliminated the toxicity. We also exposed dithiothreitol (DTT) to catalase mutant E coli strains. The results show that DTT was also toxic to the catalase mutant K colis in dose dependent manner and significantly different between Cs^a and Cs^b. Catalase, CuZnSOD, and MnSOD also showed protective ability on tester strains. Treatment with waste disposal extracted by methanol and sterilized water showed a negative relation between the exposure dose and survival of these strains. The results support the usefulness of these newly established strains for hazard identification of oxidative chemicals in a risk assessment process.
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