Bacterial mutagenicity, metabolism, and DNA adduct formation by binary mixtures of benzo[a]pyrene and 1-nitropyrene.
Air pollutants are a complex mixture containing polycyclic organic compounds. Among these are 1-NP and B[a]P, which are important contributors to the mutagenicity of diesel exhaust and airborne particulate matters. To investigate the interaction of a complex mixture of airborne mutagens, the mutagenicity of 1-NP was examined with S. typhimurium TA98 and TA98NR in the presence and absence of B[aP. B[a]P exhibited a more antagonistic effect on the mutagenicity of 1-NP in strain TA98 than in strain TA98NR. Also studied were (1) the inhibitory effects of B[a]P on the nitroreductive metabolism of 1-NP and (2) DNA adduct formation by 1-NP. Nitroreductase was associated with the metabolism of 1-NP, and was reduced in a dose-dependent manner in a binary mixture of 1-NP and B[a]P. HPLC analysis showed that the amounts of 1-AP and NAAP, the metabolites of 1-NP, were significantly decreased by the addition of B[a]P in mixtures. The results indicate that the antagonistic effect of B[a]P on the mutagenicity of 1-NP is mediated through altering its nitroreductive metabolism.
Lee
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Environmental Toxicological Center, Chung Shan Medical and Dental College, Taichung, Taiwan, R.O.C.
Cherng
S H
SH
Liu
T Y
TY
D000393:Air Pollutants / Q000633:toxicity; D000704:Analysis of Variance; D001345:Autoradiography; D001564:Benzo(a)pyrene / Q000378:metabolism / Q000633:toxicity*; D002851:Chromatography, High Pressure Liquid; D018736:DNA Adducts / Q000096:biosynthesis / Q000187:drug effects* / Q000235:genetics; D004249:DNA Damage / Q000187:drug effects / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics; D016296:Mutagenesis / Q000187:drug effects* / Q000235:genetics; D009152:Mutagenicity Tests; D009601:Nitroreductases / Q000378:metabolism; D011721:Pyrenes / Q000378:metabolism / Q000633:toxicity*; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D001335:Vehicle Emissions / Q000633:toxicity
D000393:Air Pollutants; D018736:DNA Adducts; D011721:Pyrenes; D001335:Vehicle Emissions; D001564:Benzo(a)pyrene; D009601:Nitroreductases; C032668:1-nitropyrene