J.L. Epler

Polycyclic aromatic primary amines as determinant chemical mutagens in petroleum substitutes

Petroleum crude oils and coal- and shale-derived petroleum substitutes have been separated by chemical class and the class fractions have been subjected to bacterial mutagenicity testing. Alkaline constituents of the petroleum substitutes are found to make major contributions to their mutagenicities. High-resolution chromatographic and spectroscopic analysis of alkaline subfractions enriched in mutagenic activity show the causative agents to be polycyclic aromatic primary amines. The amines may be responsible for the increased biological activity of coal- and shale-derived petroleum substitutes relative to petroleum.

Analytical and biological analyses of test materials from the synthetic fuel technologies: IV. Studies of chemical structure-mutagenic activity relationships of aromatic nitrogen compounds relevant to synfuels

Abstract Nitrogen-containing organic compounds from environmental sources are receiving increasing attention because of uniquely active mutagens which have been found in this class (Chrisp et al., 1978; Nagao and Sugimura, 1978; Guerin et al., 1980). Differences in mutagenic activities among the various organo-nitrogen compounds, i.e., pyrrole types, pyridine types and aniline types, have been noted consistently. Furthermore, differences among homologs of a particular compound type are often striking. Information in this paper engages the question of chemical structure/biological activity relationships. Activity data for several N -heterocyclic, nitro-, amino- (primary, secondary and tertiary), and amino- N -heterocyclic aromatic compounds are presented. The number of fused rings and the substituent type affect the mutagenic activities greatly. The trends observed are discussed generally with reference to molecular structural features.

Distribution of mutagenic activity in petroleum and petroleum substitutes

Abstract Several petroleum crude oils and shale- and coal-derived petroleum substitutes have been fractionated by chemical class and the fractions have been tested for mutagenic activity. Crude petroleum substitutes tend to exhibit greater mutagenicities than do petroleum crude oils but the mutagenicity is reduced to comparable levels in low-boiling distillates and samples which have been hydrotreated. The mutagenicity is caused by alkaline and neutral constituents of the petroleum substitutes, but only neutral constituents for the petroleum crudes. The mutagenic components constitute less than ten per cent of the mass of the samples.

Fractionation of synthetic crude oils from coal for biological testing

Abstract A separations procedure that has been used extensively for the reproducible fractionation of cigarette smoke condensate in order to test this material systematically for its carcinogenic properties has been applied to coal liquefaction products. Two types of product oils, one a light oil and the other a heavy tar, have been processed successfully by this procedure. Reproducibility was similar to that reported for condensate fractionations. Proportions, by weight, of fourteen major fractions and some subfractions of the two products were determined. Mutagenicity of the major fractions of the light oil product was tested by microbiological techniques using several strains of Salmonella typhimurium and some mutagenic effect was shown by four of the fractions. The possible carcinogenicity and mutagenicity of the individual fractions are discussed in relation to the reported effects of corresponding cigarette smoke condensate fractions.

Mutagenicity of N-nitrosopiperidines with Salmonella typhimurium/microsomal activation system

Abstract Using Salmonella typhimurium tester strains, we have examined N -nitropiperidine and various substituted nitrosopiperidines for their mutagenic potency. Most of the nitrosopiperidines require metabolic activation. Phenobarbital appears to be the most effective inducer of the rat liver enzymes. We also observed a correlation between mutagenicity and carcinogenic potency of these compounds. The carbon atoms alpha to the N -nitroso group seem important since blockage of those positions reduces or eliminates mutagenicity as well as carcinogenicity of the nitrosopiperidine.

Analytical and biological analyses of test materials from the synthetic fuel technologies: II. Extended genetic and biochemical studies with mutagenic fractions☆

Abstract The mutagenicity of environmental effluents from modern synthetic fuel technology has been described by Epler et al. [6]. This article reports an extensive genetic and biochemical analysis of a crude synthetic fuel, Synfuel A-3, to examine certain highly mutagenic fractions. The results indicate a frameshift mechanism for the mutagenicity of this test material which correlates with the organic constituents known or suspected to occur in it [10]. The test material requires metabolic activation in order to be mutagenic; various activating or deactivating mechanisms in the metabolic transformation are discussed.

Mutagenicity of 4,4′-MethyIenedianiline Derivatives in the Salmonella histidine reversion assay

Abstract4,4′-Methylenedianiline and its derivatives were assayed for mutagenicity in the Salmonella/microsomal mutagenicity assay developed by Ames. A specificity to revert strain TA98 suggests a mechanism of frameshift mutagenesis. Liver microsomal preparations (S-9) from rats induced with phenobarbital were most effective for metabolic activation. Alkyl substitution of 4,4′-methylenedianiline did not alter its mutagenic activity; however, substitution of both positions ortho to the amino group eliminated mutagenic activity. Substitution with alkoxy-carbonyl groups eliminated mutagenic activity, whereas halogen substitution (chlorine, fluorine) enhanced the mutagenic activity. The results presented here show the use of structure-activity studies as predictive tools for the assessment of genotoxic properties of industrial chemicals.

Comparative mutagenesis of quinolines

Abstract Quinoline, 8-hydroxyquinoline, 8-nitroquinoline, and 8-aminoquinoline are mutagenic in Salmonella when assayed by histidine reversion. Metabolic activation is required for the maximal effect. Frameshift mutagenesis appears to be the mechanism with 8-nitro- and 8-aminoquinoline. Quinoline and 8-hydroxyquinoline affect only the sensitive TA100 (missense, R factor) strain. 8-Amino-and 8-hydroxyquinolines induce chromatid aberrations in human leukocytes. 8-Nitroquinoline has no effect at the concentrations tested. 8-Aminoquinoline is not effective in yeast when assayed by forward mutation, gene conversion, or mitotic recombination; fluctuation tests show a weak effect. 8-aminoquinoline is not an effective mutagen in Drosophila when assayed for sex-linked recessive lethals by an adult feeding method.

Mutagenicity of N-nitrosopiperazine derivatives in Salmonella typhimurium.

Mutagenicity of several nitroso derivatives of piperazine was assayed using histidine auxotrophic strains of Salmonella typhimurium. Nitroso derivatives of piperazine required metabolic activation with preference to phenobarbital induced rat-liver microsomal enzymes. We observed a good correlation between a positive effect in the mutation assay and the carcinogenic potency of the compound. Even though our results are not in complete agreement with earlier published work using several microbial mutation assay systems, the differences we observed demonstrate the predictive value of an in vitro activation system using S. typhimurium to detect carcinogenic compounds as mutagens.

Separation of neutral nitrogen compounds from synthetic crude oils for biological testing

Isolation of neutral N-PAHs (PAH homologues containing one or more ring nitrogens) is achieved in three steps using acid-base extraction, gel filtration on Sephadex LH-20, and adsorption chromatography on silicic acid. Gas chromatographic/mass spectrometric analysis of the neutral N-PAH fractions indicated the following as major components: C1-C3 phenylpyrroles, indole, C1-C6 indoles, C1-C3 phenylindoles, carbazole, C1-C5 carbazoles, benzocarbazoles, and C1-C3 benzocarbazoles. The neutral N-PAH fractions were subjected to mutagenicity tests using Salmonella typhimurium/microsomal activation systems devised by Ames. The neutral N-PAH fraction of the coal-derived oil had a specific activity more than twice that of the PAH fraction of the same oil, whereas the shale oil neutral N-PAH fraction showed no activity. These results are discussed in the context of previous work with these oils and with some pure neutral N-PAH compounds.