Assessment of the performance of the Ames MPF™ assay: A multicenter collaborative study with six coded chemicals.

The Ames MPF™ is a miniaturized, microplate fluctuation format of the Ames test. It is a standardized, commercially available product which can be used to assess mutagenicity in Salmonella and E. coli strains in 384-well plates using a color change-based readout. Several peer-reviewed comparisons of the Ames MPF™ to the Ames test in Petri dishes confirmed its suitability to evaluate the mutagenic potential of a variety of test items. An international multicenter study involving seven laboratories tested six coded chemicals with this assay using five bacterial strains, as recommended by the OECD test guideline 471. The data generated by the participating laboratories was in excellent agreement (93%), and the similarity of their dose response curves, as analyzed with sophisticated statistical approaches further confirmed the suitability of the Ames MPF™ assay as an alternative to the Ames test on agar plates, but with advantages with respect to significantly reduced amount of test substance and S9 requirements, speed, hands-on time and, potentially automation.

Assessment of the miniaturized liquid Ames microplate format (MPF™) for a selection of the test items from the recommended list of genotoxic and non-genotoxic chemicals.

The Ames microplate format (MPF™) is a miniaturized version of the plate agar Ames tests that takes advantage of a liquid microplate approach in 384-well plates with a color change-based readout. This method, already compared to the Ames test in Petri dishes, is used to assess the genotoxic potential of a variety of test items, including (but not limited to) chemicals, environmental samples, and drug candidates. 61 chemicals were selected from the updated recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests and tested in up to five bacterial strains. The agreement with the data from the scientific literature (over 90%) confirms the reliability of the Ames MPF™ as a cost-effective and 3R-compliant alternative to the regulatory Ames test that allows to predict and evaluate chemicals' mutagenicity in a faster, less laborious and, if available, automatable manner.