Premium
Base‐substitution profiles of externally activated polycyclic aromatic hydrocarbons and aromatic amines determined in a lacZ reversion assay
Author(s) -
Garganta Fátima,
Krause Günter,
Scherer Gerhard
Publication year - 1999
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/(sici)1098-2280(1999)33:1<75::aid-em9>3.0.co;2-1
Subject(s) - mutagen , chemistry , pyrene , mutagenesis , ames test , benzo(a)pyrene , carcinogen , reversion , biochemistry , mutant , escherichia coli , methylnitronitrosoguanidine , stereochemistry , bacteria , organic chemistry , salmonella , genetics , biology , gene , phenotype
Using an improved set of lactose‐auxotrophic Escherichia coli tester strains, the proportion of the six possible transitions and transversions after mutagen exposure was assessed. Mutagenic specificity was determined in plate‐incorporation assays using lactose‐containing minimal medium for the selection of revertants, either after application of directly acting mutagens or by including a metabolic activation system with rat liver S9‐extract. The differential and dose‐dependent response of the six tester strains was shown by treating the bacteria with described diagnostic mutagens and other directly DNA damaging substances, e.g., N‐methyl‐N‐nitrosoguanidine (MNNG) and benzo[a]pyrene‐diolepoxide (BPDE). Polycyclic aromatic hydrocarbons and aromatic amines were investigated in the presence of an external metabolic activation system. Benzo[a]pyrene (BaP) yielded similar mutation profiles as its ultimate mutagen BPDE, if 100‐fold increased doses were applied. In contrast to the mutation profile of BaP, which was dominated by G:C–T:A transversions, mutagenesis with benzo[c]phenanthrene (BcPh) produced predominantly A:T–T:A transversions. The same base change was observed with 5‐methylchrysene and found to be missing with 5,6‐dimethylchrysene, while both compounds caused G:C–A:T transitions. The aromatic amines 4‐aminobiphenyl (4‐ABP), 2‐aminoanthracene (2‐AA) and 2‐amino‐1‐ methyl‐6‐phenylimidazo[4,5‐ b ]pyridine (PhIP) yielded similar yet distinguishable mutation profiles. Base‐substitution reversion profiles of the chemical mutagens were in agreement with those obtained in other systems and with molecular analysis of mutants induced by these agents. Environ. Mol. Mutagen. 33:75–85, 1999 © 1999 Wiley‐Liss, Inc.