ABSTRACT

Using the test of somatic mutation and recombination (SMART) the mutagenic activity was studied in two cross-breed Drosophila melanogaster strains. In the strain mwh x ORR;flr3/TM3, Ser the concentration of cytochrome P-450-associated enzymes necessary faetivation of many promutagens, e.g. benzo(a)pyrene is many times higher. Cyclohexane extracts of atmospheric dust and certain polycyclic aromatic hydrocar­bons were studied separately or in combination of two different ones. The study showed that:
- reliable results of the determinations of the mutagenicity of various polycyclic aromatic hydrocarbons were obtained only with the strain with high activity of enzymes activating promutagens, that is strain OR;f1t3/TM3,Scr;
-mixtures of promutagens in concentrations of several mmols can show lower mutagenicity than the most mutagenic component of the mixture given separately. This could be the cause of stopped rise of the dose-response curve;
-an overwhelming majority of mutations in studies of tar substaces is not due to the action of strongly acting promutagens among the polycyclic aromatic hydroarbons studied here, including BaP.