What does the Ames test screen for?
Ames Test, named after the scientist Bruce Ames who first described it, is basically a biological assay or an agar plate that contains certain strains of the bacterium Salmonella typhimurium along with small amounts of histidine. The test is used to screen a given chemical substance for its mutagenic and, hence, carcinogenic potential (This is because a substance that can cause mutation or change in the DNA structure is likely to also cause cancer). A positive result of the test implies that the chemical substance under consideration has the ability to cause cancer. There are several problems with the test, however, and it is not foolproof. It shows negative results for certain carcinogenic substances and positive result for certain non-carcinogenic substances. Nonetheless, it still has a known potential to screen many carcinogens and, thus, finds application majorly in the drug testing industry.
The Ames test screens for carcinogens essentially. The test can determine if a chemical is mutagenic. If it is, it may be able to show if something is a carcinogen i.e. cancer causing. The Ames test is fairly inexpensive and therefore very valuable for screening environmental substances that are possibly carcinogenic.
An Ames test screens for the mutagenic properties of a substance. A substance with mutagenic properties can change genetic material, usually DNA. Cancer is often linked to DNA damage; there for a substance that has mutagenic properties has the potential to cause cancer. The Ames test does come up with a number of false positives and false negatives but is still seen as a strong way to measure the carcinogenic potential of a substance (likelihood of causing caner). Bruce Ames and his colleagues at the University of California Berkely developed this test which has since gone on to identify the carcinogenic properties of such things as DDT, flame retardant ‘tris-BP’ and compounds in commercial hair dyes. The Ames test also found the mutagenic properties of the food additive AF-2 which is no longer used. The Ames test has become an important tool used to test the carcinogenic potential of a substance.