A new Salmonella typhimurium NM5004 strain expressing rat glutathione S-transferase 5-5: use in detection of genotoxicity of dihaloalkanes using an SOS/umu test system.
The Escherichia coli mu operon was subcloned into a pKK233-2 vector containing rat glutathione S-transferase (GST) 5-5 cDNA and the plasmid thus obtained was introduced into Salmonella typhimurium TA1535. The newly developed strain S.typhimurium NM5004, was found to have 52-fold greater GST activity than the original umu strain S.typhimurium TA1535/pSK1002. We compared sensitivities of these two tester strains, NM5004 and TA1535/pSK1002, for induction of umuC gene expression with several dihaloalkanes which are activated or inactivated by GST 5-5 activity. The induction of umuC gene expression by these chemicals was monitored by measuring the cellular beta-galactosidase activity produced by umuC"lacZ fusion gene in these two tester strains. Ethylene dibromide, 1-bromo-2-chloroethane, 1,2-dichloroethane, and methylene dichloride induced umuC gene expression more strongly in the NM5004 strain than the original strain. 4-Nitroquinoline 1-oxide and N-methyl-N'-nitro-N-nitrosoguanidine were found to induce umuC gene expression to similar extents in both strains. In the case of 1-nitropyrene and 2-nitrofluorene, however, NM5004 strain showed weaker umuC gene expression responses than the original TA1535/pSK1002 strain. 1,2-Epoxy-3-(4'-nitrophenoxy)propane, a known substrate for GST 5-5, was found to inhibit umuC induction caused by 1-bromo-2-chloroethane. These results indicate that this new tester NM5004 strain expressing a mammalian GST theta class enzyme may be useful for studies of environmental chemicals proposed to be activated or inactivated by GST activity.
Oda
Y
Y
Osaka Prefectural Institute of Public Health, Japan.
Yamazaki
H
H
Thier
R
R
Ketterer
B
B
Guengerich
F P
FP
Shimada
T
T
D015112:4-Nitroquinoline-1-oxide / Q000378:metabolism / Q000633:toxicity; D000818:Animals; D001711:Biotransformation; D004980:Ethane / Q000031:analogs & derivatives / Q000378:metabolism / Q000633:toxicity; D015946:Ethylene Dibromide / Q000378:metabolism / Q000633:toxicity; D005025:Ethylene Dichlorides / Q000378:metabolism / Q000633:toxicity; D005449:Fluorenes / Q000378:metabolism / Q000633:toxicity; D015870:Gene Expression / Q000187:drug effects; D005822:Genetic Vectors / Q000235:genetics*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D006846:Hydrocarbons, Halogenated / Q000378:metabolism / Q000633:toxicity*; D008752:Methylene Chloride / Q000378:metabolism / Q000633:toxicity; D008769:Methylnitronitrosoguanidine / Q000378:metabolism / Q000633:toxicity; D009152:Mutagenicity Tests; D009876:Operon / Q000235:genetics*; D011721:Pyrenes / Q000378:metabolism / Q000633:toxicity; D051381:Rats; D012486:Salmonella typhimurium / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D014162:Transfection; D014169:Transformation, Bacterial
D005025:Ethylene Dichlorides; D005449:Fluorenes; D006846:Hydrocarbons, Halogenated; D011721:Pyrenes; D008769:Methylnitronitrosoguanidine; C019499:2-nitrofluorene; D015946:Ethylene Dibromide; C024565:ethylene dichloride; D015112:4-Nitroquinoline-1-oxide; D008752:Methylene Chloride; C039590:1-bromo-2-chloroethane; D005982:Glutathione Transferase; D004980:Ethane; C032668:1-nitropyrene