Gene mutation assays Ames test

Assays for Gene Mutations Salmonella Typhimurium reverse mutation assay (Ames test, / ... 

The bacterial and mammalian cell assays for gene mutation were developed to measure statistically significant increases in the numbers of mutant colonies derived from rare events many millions of exposed cells must be plated out to allow the assessment of mutation frequency. The Salmonella typhimurium reverse mutation assay ( Ames test) is carried out in a variety of different mutant strains selected to identify the various classes of mutation. The test generates many hundreds of Petri dishes for counting and is not practical for profiling. 

In general, genotoxicity standard assays (e.g., bacterial reverse mutation assay [Ames test], in vitro chromosomal aberration assay, mouse lymphoma gene mutation assay, and rodent micronucleus assay) may not be suitable assays because the test cells do not contain the appropriate receptors to transport the product (i.e.,not a relevant species) or because the biopharmaceutical... 

Twenty-seven out of 44 FDA-approved biopharmaceuticals have been tested in a battery of genotoxicity assays. Eighty-five different assays performed yielded negative results. The most commonly performed assays were the Ames test, the chromosomal aberration assay in human lymphocytes, the mouse lymphoma gene mutation assay, and the mammalian in vivo erythrocyte micronucleus test. Examples of the range of biopharmaceutical products tested include, domase alfa (deoxyribonuclease I-DNAse), trastuzumab (mAb to human epidermal growth factor receptor 2), alteplase (tissue plasminogen activator), infliximab (mAb to the human tumor necrosis factor a). 

Prenatal and postnatal development none Genetic toxicology0 Ames test, human lymphocyte chromosomal aberration assay, CHO/HGPRT gene mutation assay, mouse micronucleus assay Carcinogenicity none... 

In Ames and micronucleus tests of urine from human volunteers administered the compound arbutin at doses of 420 mg, no mutagenic or genotoxic activity was observed (Siegers et al. 1997). No mutagenicity of arbutin was observed in a gene mutation assay at a concentration of 0.01 M, whereas the compound hydroquinone caused an increase in mutation frequency at a concentration of 0.01 M (Mueller and Kasper 1996). 

No genotoxic activity of European mistletoe was observed in a variety of assays, including a bacterial mutation assay, mammalian cell gene mutation assay, in vitro cytogenetic assay, cell transformation assay, and the Ames test (Mengs 1998 Mengs et al. 1997). 

Not mutagenic according to Ames test, cytogenicity study and gene mutation assay. 

Feeding (Dietary) Gene Mutation Assay (e.g., Ames Test)... 

The mutagenic potential of diisopropyl methylphosphonate was investigated using the Ames assay. The compound was obtained from two different sources and tested on Salmonella typhimurium strains TA-1535, TA-1537, TA-1538, TA-98, and TA-100, both with and without S-9 activation. The compound did not demonstrate mutagenic activity in any of the assays (Hart 1980). Diisopropyl methylphosphonate was also negative for gene mutation in Saccharomyces cerevisiae (Hart 1980). 

The use of yeast cells as a eukaryotic complement to the Ames test led to the development of several protocols for the detection of mutation, gene conversion and recombination. The formal introduction of methods [23] followed by much development work from Zimmermarm s laboratory led to large systematic studies [24, 25] and OECD guidelines for the test battery (OECD 480, 481). However the assays are now rarely used, at least in part because of concerns over low sensitivity, thought to reflect limited permeability of the cell wall. 

Phosphine has been reported as negative for induction of reverse gene mutations up to cytotoxic doses in the Ames assay Salmonella typhimurium). Increased chromosomal aberrations were reported in Chinese hamster ovary (CHO) cells exposed to 2500 and 5000 ppm of phosphine without activation with the S9 fraction. Chromosomal aberrations in CHOs were also reported in cells tested with S9 activation at 2500 ppm, but not 5000 ppm. 

Alosetron was not genotoxic in the Ames tests, the mouse lymphoma cell (L5178Y/TK +) forward gene mutation test, the human lymphocyte chromosome aberration test, and the rat hepatocyte unscheduled DNA synthesis test. Nonmutagenic in the rat micronucleus assay. 

Cytogenetic examination of bone marrow cells showed no increase in aberrations in maternal and neonatal rats following maternal oral exposure to a DeBDE and NoBDE mixture. In vitro assays found that DeBDE did not induce gene mutations in several bacterial tests (Ames assays) or in mammalian cells. DeBDE also did not induce chromosomal aberrations in Chinese hamster ovary cells. However, exposure to the congeners 2,2, 4,4 -tetra-BDE, 3,4-diBDE, and 2-monoBDE caused increased recombinogenic activity at the HGPRT locus in several cell lines. 

---