Improvement in the sensitivity of DNA polymerase I-deficient Escherichia coli for detecting mutagens and carcinogens.

The sensitivity of a polA strain to the antibacterial activity of mutagens and carcinogens may be increased by inserting one or both of the following characteristics, a lexA mutation or the R391 bacterial plasmid. The effects of the lexA mutation and the plasmid appear to be additive. The differential sensitivity of a polA lexA (R391) strain could be adapted as a preliminary screening test for mutagens and potential carcinogens.