Use of flow cytometry to detect genotoxins by the Salmonella sulA-test

The Salmonella sulA-test using Salmonella typhimurium TA1538/pEM1968 ( sulA:: lacZ) is a new SOS-repair inducing system that detects mutagens and carcinogens. The b-galactosidase activity, currently detected by colorimetric dosage, can be measured by flow cytometry using a fluorescent substrate (fluorescein-di-b-D-galactopyranoside). Comparison of the dose-response relationships of eight chemicals determined by the two techniques showed that the Salmonella sulA-test combined with the flow cytometry technique was accurate and reliable as it covered a large number of cells in a short time.