Literature survey of bacterial, fungal, and Drosophila assay systems used in the evaluation of selected chemical compounds for mutagenic activity.

Literature reports were surveyed, with results noted from experiments in seven nonmammalian assay systems used for the detection of mutagenicity or other related genetic effects. A comparison was made of the activities of 54 selected noncarcinogens, procarcinogens, and ultimate carcinogens as revealed by these test systems. Of the compounds tested, 49 (91%) were active in one or more of the assays, and 42 (78%) were positive in at least one system without having to be metabolically activated. In one or more test systems, 17/17 (100%) of the ultimate carcinogens, 27/28 (96%) of the procarcinogens, and 6/9 (67%) of the noncarcinogens were positive. The Ames Salmonella-microsome assay responded with increased mutation frequency to 37/44 (84%) of the carcinogenic compounds but to only 2/8 (25%) of the noncarcinogens tested. The Drosophila system responded to 19/21 (90%) of the carcinogens and to 3/6 (50%) of the noncarcinogens. Prophages were induced when lysogenic bacteria were exposed to 12/21 (57%) of the carcinogens, but not enough tests were done with the noncarcinogens (1/3, or 33%) for a comparison. The other systems reviewed, such as the killing of repair-deficient bacteria, mutations in Escherichia coli and Neurospora crassa, and the host-mediated assay, were not challenged by enough of the compounds for valid comparisons.