Bacterial reverse-mutation tests

Figure 4.7 An explanation of the bacterial reverse-mutation test (the Ames test).

Genotoxicity Bacterial reverse mutation test (Ames test) OECD, US Approved... 

Bacterial Reverse Mutation Test (Updated Guideline, adopted 21 July 1997)... 

The 3R concept lies behind efforts to improve ethical standards for the use of experimental animals throughout the scientific community, including toxicity testing. A number of in vitro methods for genetic toxicology testing have been established as guideline methods for many years, e.g., the bacterial reverse mutation test, more popularly known as the Ames test. 

The bacterial reverse mutation test OECD TG 471 US-EPA OPPTS 870.5100 EU Annex VB. 13/14... 

Positive results from the bacterial reverse mutation test (often referred to as the Ames test) indicate that a substance induces point mutations by base pair substimtion or frameshift in the... 

An extensive database has demonstrated that many chemicals that are positive in this test also exhibit mutagenic activity in other tests. There are, however, examples of mutagenic substances, which are not detected by this test reasons for these shortcomings can be ascribed to the specific nature of the endpoint detected, differences in metabolic activation, or differences in bioavailability. On the other hand, factors which enhance the sensitivity of the bacterial reverse mutation test can lead to an overestimation of mutagenic activity. The bacterial reverse mutation test may not be appropriate for the evaluation of certain classes of chemicals for example, highly bactericidal compounds (e.g., certain antibiotics) and those which are thought (or known) to interfere specifically with the mammalian cell replication system (e.g., some topoisomerase inhibitors and some nucleoside analogues). In such cases, mammalian mutation tests may be more appropriate. 

ETAD Information No.7, Significance of the Bacterial Reverse Mutation Test as Predictor for Rodent and Human Carcinogenity, Basle, 1998. 

Bacterial reverse mutation test Ames Test Gene mutations Basepair substitution, addition or deletion... 

The bacterial reverse mutation test (Ames Test) investigates the ability of chemicals and drags to induce reverse (back) mutations in bacteria, which involves base pair substitutions additions and/or deletions (frameshift mutations) of one or a few DNA base pairs. The bacterial strains used in the test system have mutations in genes coding for enzymes required for the biosynthesis of the amino acids histidine (Salmonella typhimurium) and tryptophan (Escherichia coli). If... 

The advantages of the bacterial reverse mutation test are the ease with which it can be performed, the short amount of time required and the low cost. The test should be regarded as the first test in the GLP testing strategy for the detection of a genotoxic potential of a test compound. 

The bacterial reverse mutation test does not detect all compounds with the potential to induce point mutations. For some chemical series, modifications of the test system are necessary. For example, the potential for azo compounds to induce point mutations can only be detected by using an S9-mix prepared by hamster liver. To get an indication early in the development of a test compound for its potential to induce point mutations, modified test systems of the... 

OECD (1997) Guideline For Testing Of Chemicals, 471, Bacterial Reverse Mutation Test. Adopted 21-Jul-1997, U.S. EPA OPPTS 870.5100... 

Based on evidence derived from a large array of assays such as bacterial reverse mutation test, mammalian bone marrow chromosome aberration test, dominant lethal assay, and UDS assay, atrazine was concluded to lack mutagenic potential. 

Fenthion did not show evidence of mutagenicity in the bacterial reverse mutation test or in the chromosome aberration test in Chinese hamster ovary cells. A test of unscheduled DNA synthesis in rat he-patocytes was also negative. Fenthion showed a weakly positive response in 2 of 5 assays for sister chromatid exchange. 

The primaiy eye tolerance tests showed that the Saro essential oil has eye irritation levels of 2.8 on a scale of 9 and thus, can be considered as a low irritant oil, since its value is within 1 and 5 of the scale. The study appeared to be valid according to the criteria specified in the international guidelines and the Saro essential oil did not show any mutagenic activity in the bacterial reverse mutation test with S, typhimurium. 

OECD (1997) Test No. 471 Bacterial Reverse Mutation Test OECD publishing... 

Asquith J, Pickering K, Trenchard-Morgan S, Sangster S (1986) Completion of bacterial reverse mutation test on isomaltulose. Toxicol Lab Ltd, Ledbury, Herefordshire... 

Assessment of genotoxicity in a bacterial reverse mutation test (Ames Test, see Exhibit 5.6)... 

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