Growth-mediated metabolic activation of promutagens in Aspergillus nidulans

7 procarcinogens belonging to different chemical classes (nitrosamines, hydrazoalkanes, oxazaphosphorines and aromatic amines) were tested in A. nidulans for the induction of point mutations with two genetic systems (8-AG resistance and induction of methionine suppressors).

Dimethylnitrosamine, diethylnitrosamine, nitrosomorpoline, dimethyl-hydrazine, procarbazine and cyclophosphamide gave positive results with a good dose—effect relationship in the growth-mediated assay, whereas they gave negative or borderline positive results in the plate incorporation assay. 2-Aminoanthracene was completely negative with both experimental procedures.

DMN, DEN and NM were also tested for their ability to induce somatic segregation: all were positive when assayed in the growth-mediated assay.