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... 

In vitro mammalian cell gene mutation test OECD, US... 

Matsushima T, Muramatsu M, Haresaku M. 1985. Mutation tests on Salmonella typhimurium by the preincubation method. In Ashby J, de Serres FJ, et al., eds. Progress in mutation research. Vol. 5. Evaluation of short-term tests for carcinogens. Amsterdam, The Netherlands Elsevier Science Publishers, 181-186. 

The mouse lymphoma forward mutation test at the thymidine kinase locus (detects mutations to a nonfunctional thymidine kinase in a line of culture mouse lymphoma cells). 

The Ames Salmonella typhimurium microsome reverse mutation test (ability to produce point gene mutations of a base pair). 

Macgregor, J.T., D.H. Gould, A.D. Mitchell, and G.P. Sterling. 1979. Mutagenicity tests of diflubenzuron in the micronucleus test in mice, the L5178Y mouse forward mutation assay, and the Ames Salmonella reverse mutation test. Mutat. Res. 66 45-53. 

Protocol for Dose Ranging and Selection. Before carrying out the main tests, it is necessary to carry out a preliminary toxicity dose ranging test. This should be carried out following the same basic protocol as the mutation test, except that instead of scoring the number of mutants on, for example minimal media plates with limiting amounts of a required amino acid, the number of survivors is scored on fully supplemented minimal media. A typical protocol is outlined below. 

Forward Mutation Tests. Forward mutation is an endpoint that may arise from various events, including base substitutions, frameshifts, DNA deletions, and so on, as mentioned earlier. 

In vivo mammalian mutation tests are not restricted to germ cell tests. The mouse spot test described below is, again, a test used first for studying radiation-induced mutation but has also been used for screening chemicals for in vivo mutagenic potential. This test has had several proponents but compared with in vivo chromosomal assays is not widely used. 

In Vitro Mammalian Cell Gene Mutation Test (Using Mouse Lymphoma... 

In the bacterial mutation test, the mutagenic potential of a pharmaceutical and its metabolites is evaluated by measuring and quantifying its ability to induce reverse mutations at selected loci of Salmonella typhimurium or Escherichia coli in the presence and absence of metabolic activation. This test system has been shown to detect a diverse group of chemical mutagens.3,4 The technical details of this test have been reported in the literature.5-7... 

Chamberlain, M., and C. M. Tarmy (1977). Asbestos and glass fibers in bacterial mutation tests. Mutagen. Res. 43 159-164. 

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

B.13/14 Mutagenicity - Reverse Mutation Test Using Bacteria (2000)... 

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. 

In vitro mammahan cell gene mutation test 1998... 

B.13/14 Mutagenicity Reverse mutation test using bacteria 2000... 

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

The test is commonly employed as an initial screen for genotoxic activity and, in particular, for point mutation-inducing activity. It detects point mutations, which involve substimtion, addition or deletion of one or a few DNA base pairs. The reverse mutation test in either Salmonella typhimurium or Escherichia coli detects mutation in an amino acid requiring strain (histidine or tryptophan, respectively) to produce a strain independent of an outside supply of amino acid. The principle of the test is that it detects mutations, which revert mutations present in the test strains and restore the functional capability of the bacteria to synthesize an essential amino acid. The revertant bacteria are detected by their ability to grow in the absence of the amino acid required by the parent test strain. 

---