For pharmacology and genetics, the Umu Chromotest, first developed and published by Oda et al.,[1] is a biological assay (bioassay) to assess the genotoxic potential of chemical compounds.
A simple colorimetric test is possible by adding a lactose analog which is degraded by β-galactosidase, producing a colored compound which can be measured quantitatively through spectrophotometry.
The degree of color development is an indirect measure of the β-galactosidase produced, which itself is directly related to the amount of DNA damage.
If genotoxic lesions are produced in the bacterial genome, the umuC gene is induced as part of the general SOS response.
S. typhimurium bacteria in the exponential phase of growth are exposed for 2 hours to decreasing concentrations of test sample in triplicate, including positive and negative controls, as well as blanks.