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2134161 
Journal Article 
Effect of nitro substitution on the light-mediated mutagenicity of polycyclic aromatic hydrocarbons in salmonella typhimurium TA98 
White, GL; Fu, PP; Heflich, RH 
1985 
1 
Mutation Research
ISSN: 0027-5107
EISSN: 1873-135X 
144 
1 
1-7 
English 
3897840 
WOS:A1985AQQ6900001 
The effects of nitro substitution on the light mediated mutagenicity of four polycylic aromatic hydrocarbons (PAH) were studied in Salmonella-typhimurium. Benzo(a)pyrene (50328), benzo(e)pyrene (192972), benz(a)anthracene (56553), fluorene (86737), and their major nitration products, 6-nitrobenzo(a)pyrene (63041907), 3-nitrobenzo(e)pyrene, 7-nitrobenz(a)anthracene and 2-nitrofluorene (607578) were exposed to simulated sunlight or cool white fluorescent light. Triplicate assays were performed with Salmonella strain TA-98, and comparison studies were made with two TA-98 sub strains. A compound was considered mutagenic if it produced at least twice the number of revertants per plate produced by the non irradiated solvent control. Benzo(a)pyrene, benz(a)anthracene, 6-nitrobenzo(a)pyrene, and 7-nitrobenz(a)anthracene were not mutagenic to TA-98 without light exposure, and benz(a)anthracene was not mutagenic after irradiation for as long as 300 minutes. The other compounds were activated to mutagens by exposure to light from either source. Although for each of the nitro substituted PAH the maximum mutagenic responses produced by the two types of light were about equal, shorter periods of irradiation with sunlight were required to reach these maxima. The light mediated mutagenic activities of 7-nitrobenz(a)anthracene, 3-nitrobenz(a)pyrene, and 2-nitrofluorene were lower in the other two Salmonella strains. Since one sub strain was deficient in a bacterial nitroreductase and the other was deficient in an esterase that acetylates N-hydroxy arylamines, it appeared that the mutagenicities of the photoproducts produced from these nitro substituted PAH were at least partially dependent on the bacterial metabolism of the nitro group. The authors conclude that nitro substitution can enhance the ability of light to activate PAH to mutagenic derivatives.