The Ames test: a methodological short review

The Ames Salmonella/microsome mutagenicity assay (Salmonella test; Ames test) is a short-term bacterial reverse mutation assay specifically designed to detect a wide range of chemical substances that can produce genetic damage that leads to gene mutations. The test is used to evaluate the mutagenic properties of test articles. The Ames test uses amino acid-dependent strains of Salmonella typhimurium and Escherichia coli, each carrying different mutations in various genes in the histidine operon. These mutations act as hot spots for mutagens that cause DNA damage via different mechanisms. In the absence of an external histidine source, cells cannot grow and form colonies. Only those bacteria that revert to histidine independence (his+) are able to form colonies. The number of spontaneously induced revertant colonies per plate is relatively constant. However, when a mutagen is added to the plate, the number of revertant colonies per plate is increased, usually in a dose-related manner. The Ames test is used worldwide as an initial screen to determine the mutagenic potential of new chemicals and drugs. The purpose of this publication is to help researchers who apply the Ames test in their studies