The E. coli Pol A-1 assay: a quantitative procedure for diffusible and non-diffusible chemicals

A procedure is described for determining the preferential killing of DNA repair-deficient E. coli. Dilute suspensions of DNA repair-proficient and -deficient bacteria are exposed to a graded series of test chemical concentrations. Survivors are determined by enumeration on agar plates. An expression used to express preferential killing (or lack thereof) is shown to be dose-dependent and potentially useful for determining genotoxic potencies.