title: The variation on the mutagenicity of CNP during anaerobic biodegradation.
abstract: The mutagenicity of water, including herbicide CNP, and its time-variation during anaerobic biodegradation were studied through Ames assay using strains with or without. S9 mix: TA98, TA 100, YG1021, YG1024, YG1026, and YG1029. The bacteria, for the anaerobic biodegradation, was obtained from a paddy field, and preincubated for a month. The CNP was decomposed in an anaerobic culture inoculated with the bacteria, and finally yielded CNP-amino as one of the CNP metabolites. About 16% of the initial CNP was transformed into CNP-amino by the 14th day. The mutagenicities to TA98. YG1024, and YG1029 strains with S9 mix increased with cultivating time, the latter two showed the strongest sensitivity to CNP-amino. The contribution of CNP to the mutagenicity decreased as the chemical decomposed, while the contribution of CNP-amino increased. However, the increased mutagenicity was not limited to the contribution of CNP-amino. but also to the contribution of other metabolites. The contributions of other CNP metabolites were 67% of total mutagenicity to the TA98 strain and 30% to the YG1029 strain. These unknown mutagenic metabolites were the indirect frameshift mutagens which did not have nitro- and amino-substituents, and the indirect base-pair mutagens which might possibly have some amino-substituents.
authors.affiliation: Department of Civil Engineering, Gifu University, Japan. taku_m@cc.gifu-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Matsushita
authors.forename: S
authors.initials: S
authors.lastname: Sakuma
authors.forename: K
authors.initials: K
authors.lastname: Nakamuro
authors.forename: Y
authors.initials: Y
authors.lastname: Matsui
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001421:Bacteria, Anaerobic / Q000187:drug effects*; D001673:Biodegradation, Environmental; D006540:Herbicides / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D008297:Male; D015394:Molecular Structure; D009152:Mutagenicity Tests; D009153:Mutagens / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D010647:Phenyl Ethers / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D006540:Herbicides; D009153:Mutagens; D010647:Phenyl Ethers; D014874:Water Pollutants, Chemical; C010422:2,4,6-trichlorophenyl 4-nitrophenyl ether; C067259:2,4,6-trichlorophenyl-4'-aminophenyl ether