Genotoxicity testing of six insecticides in two crosses of the Drosophila wing spot test

Among the great variety of genotoxicity assays available, the wing spot tes t in Drosophila melanogaster has same characteristics that make it very sui ted for the screening of genotoxic activity, i.e., it is an easy and inexpe nsive assay using a eukaryotic organism in vivo. One of the most interestin g characteristics of the assay is its capacity to detect genotoxic activity of promutagens without the necessity of an exogenous metabolic activation system. In this paper we present results obtained with a recently developed high bioactivation cross of the wing spot test (NORR cross). The positive results obtained with the five well-known procarcinogens 7,12-dimethylbenz[ a]anthracene, N-nitrosopyrrolidine, p-dimethylaminoazobenzene, diethylnitro samine and urethane clearly show that the NORR strains are similar to the o ther high bioactivation strains previously described, but they lack their m ethodological disadvantages. We have tested six insecticides, which are cha racterised by having contradictory results in other genotoxicity tests, usi ng both the standard and the high bioactivation (NORR) cross, The six insec ticides analysed are the pyrethroid allethrin, the methylenedioxyphenolic c ompound piperonyl butoxide, the chlorinated hydrocarbons dieldrin and endri n, and the organophosphates dimethoate and malathion. We obtained negative results for all six compounds. Our results show the suitability of the wing spot test for the evaluation of compounds at the first level of genotoxici ty testing. (C) 1999 Elsevier Science B.V. All rights reserved.