SOS chromotest, a quantitative short-term bacterial assay for the detection of genotoxic compounds in an automated version adapted to Bioscreen Analyzer System.

The SOS chromotest is a simple quantitative short-term bacterial assay for the detection of genotoxic activity of pure chemicals or complex samples. The test is based on the measurement of the induction of the SOS response by xenobiotics which cause damage in replicating or non replicating DNA. The assay has been originally developed as a test-tube method but has recently been modified and extensively evaluated (Quillardet and Hofnung 1985, Quillardet et al. 1985). In an attempt to automate the SOS chromotest a manual test procedure based on microtiter plates (Orgenics Ltd. 1986) has been further adapted to Bioscreen analyzer system (Labsystems OY, Helsinki, Finland). In this application the test is controlled by a self-contained, interactive programme and makes use of a kinetic measure principle for quantifying the enzymatic activities to be evaluated. The present experiences with the automated version of the SOS chromotest indicate its usefulness as primary screening method or part of a battery of bacterial short-term tests for genotoxins and point out its remarkable practical advantages.