Principle of the MicroAmes1 Test

The MacroAmes1 kit includes reagents for the bacterial reverse mutation test: Point mutations were made in the histidine (Salmonella typhimurium) operon, rendering the bacteria incapable of producing the corresponding amino acid. These mutations result in his- organisms that cannot grow unless histidine is supplied.

A test sample’s mutagenic potential is assessed by exposing these amino acid-requiring organisms to varying concentrations of sample and selecting for the reversion event. Media lacking the specific amino acid are used for this selection which allow only those cells that have undergone the reversion to histidine prototrophy to survive and grow. A mutagenic event causing base substitutions or frameshifts within the gene may cause a reversion to amino acid prototrophy. These reverted bacteria will then grow in histidine-deficient media whereas non reverted bacteria will not be able to grow.

The strains provided in this kit are the Salmonella typhimurium strain TA98 strain, suitable for the detection of frameshift mutations, and TA100, which detects base-pair substitutions.