Ames test


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Ames test

 [āmz]
a test for mutagenic substances, in which a strain of Salmonella typhimurium that lacks the enzyme necessary for histidine synthesis is cultured in the absence of histidine and in the presence of the suspected mutagen. If the substance causes DNA damage resulting in mutations, some of the bacteria will regain the ability to synthesize histidine and will proliferate to form colonies.

Ames test

(āmz),
a screening test for possible carcinogens using strains of Salmonella typhimurium that are unable to synthesize histidine; if the test substance produces mutations that regain the ability to synthesize histidine, the substance is carcinogenic.
Synonym(s): Ames assay

Ames test

n.
A test used to determine the mutagenic potential of a substance, in which salmonella bacteria that are unable to synthesize histidine are introduced into the substance, and the substance is deemed mutagenic and carcinogenic if the bacteria regain the ability to synthesize histidine.

Ames test

[āmz]
Etymology: Bruce Nathan Ames, American molecular geneticist, b. 1928
a method of testing substances for possible carcinogenicity by exposing a strain of Salmonella to a sample of the substance. The rate of mutations observed is interpreted as an indication of the carcinogenic potential of the substance tested. Also called mutagenicity test.

Ames test

A bioassay that detects genetic mutations, which is used to screen for compounds with carcinogenic potential.

Ames test

(āmz test)
A screening procedure for possible carcinogens using strains of Salmonella typhimurium that are unable to synthesize histidine; if the test substance produces mutations that regain the ability to synthesize histidine, the substance is carcinogenic.

Ames test

or

mutatest

a technique devised in the USA by Bruce Ames and an associate that is designed to screen environmental chemicals for mutagenicity. The test generally uses histidine-requiring mutant strains of the bacterium Salmonella typhimurium as the ‘tester strains’ and measures the frequency of BACK MUTATIONS where the mutants no longer require histidine supplements in their food supply. Many of the tester strains also have mutations that increase permeability to certain chemicals and enhance mutagenic effects by being defective in DNA REPAIR systems. The Ames test has been employed widely since 1975 as a check for potential CARCINOGENS, since these chemicals usually act as MUTAGENS.

Ames,

Bruce N., U.S. molecular geneticist, 1928–.
Ames assay - a screening test for possible carcinogens. Synonym(s): Ames test
Ames test - Synonym(s): Ames assay

Ames test

a test for mutagenic substances, in which a strain of Salmonella typhimurium that lacks the enzyme necessary for histidine synthesis is cultured in the absence of histidine and in the presence of the suspected mutagen treated with liver extract. If the substance causes DNA damage resulting in mutations, an increased number of the bacteria will regain the ability to synthesize histidine and will proliferate to form colonies. An important test for detecting potentially carcinogenic agents such as agricultural chemical and food additives.
References in periodicals archive ?
It can therefore be concluded that cases, where the suitability of the established in vitro tests for the determination of genotoxicity, including the Ames test and in vitro mammalian cell tests in combination with metabolic activation (OECD 1997), can be questioned, are not likely to occur with medicinal herbal extracts.
Current screens for mutagencity use modified Ames bacterial tester strains, are run without a mammalian metabolic activation system, or are performed with just two of the five regulatory ICH-compliant tester strains often under conditions different than those of the regulatory Ames test.
Ennever says their data show that if these inconclusive results are eliminated, in contrast to the NIEHS findings, "the battery does indeed do better than the Ames test alone.
The Ames test performed by Shepson and colleagues at Northrop, together with researchers at two local Environmental Protection Agency laboratories, examined the ability of toluene and its breakdown products to induce mutations in bacteria.
This system is designed to replace the most widely used in vitro assay in the world, the Ames Test.
The company believes that the AMAX(tm) system offers customers several scientific and economic advantages over the traditional Ames test, including lower cost, ease of use and the ability to automate the assay on a laboratory robotics system, making it suitable for high-volume screening.
The following tests for mutagenic potential were negative: (1) in vivo (mouse) cytogenetic assay; (2) in vitro chromosomal aberration assay; (3) alkaline elution assay; (4) V-79 assay; and (5) Ames test.
We have utilized modified Ames tests, superoxide scavenging assays, and assays for protection against DNA scissions to compare and contrast the protective effects of various teas and commercial and laboratory-isolated tea components to those produced by compounds such as resveratrol, selenium, curcumin, vitamins C and E, quercetin dihydrate, sulforaphane, ellagic acid dihydrate, glutathione reduced, trolox, butylated hydroxanisole (BHA), butylated hydroxytoluene (BHT), and N-acetyl-L-cysteine (NAC).