An E coli microsuspension assay for the detection of DNA damage induced by direct-acting agents and promutagens.

We have devised a microsuspension assay utilizing E coli indicator strains WP2, WP2 uvrA, WP67, CM611, WP100, W3110polA+, and p3478 pola- for the detection of chemically-induced preferential kill of repair-deficient strains. Data are presented from tests of 77 compounds representing a wide range of chemical classes which demonstrate the efficiency of the E coli microsuspension assay as both a qualitative and quantitative screen of DNA-modifying activity. Furthermore, the use of a battery of indicator strains lacking different repair systems offers the advantage of providing preliminary information concerning the mechanism of DNA damage induction by a test agent.