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Ames Mutagenicity Test

The Ames Mutagenicity Test is used world-wide as an initial screen to determine the mutagenic potential of organic compounds and drug leads. BioDuro has just launched a highly sensitive miniaturized screening version of the Ames test that only requires a very small amount of compound, 4-fold less test sample than the traditional agar plate-based assay. Using this assay, we can screen compounds early in the drug discovery process to identify compounds with mutagenicity liability, thus helping to prioritize chemical series or address this potential genotoxicity issue early on during lead optimization.

The available bacterial strains include Salmonella typhimurium and Escherichia coli strains listed in OECD 471 (TA98, TA100, TA1535, TA1537, E. coli uvrA). The miniaturized Ames test follows the same principle and quality control specifically referred to in OECD Guideline 471, REACH and ICH Guideline M7, and is widely used by major pharmaceutical and chemical companies worldwide.

Assay Principle

Our Ames test assay is an adapted high-throughput fluctuation method for performing the Ames bacterial mutagenicity test to detect multiple forms of mutations including frameshifts and base-pair substitutions. Hisˉ or Trpˉ tester strains are incubated with the test chemical and scored for colony growth, an indication that reversion to His+ or Trp+ phenotype has occurred. It provides a fast, simple and reliable test of reverse mutants.

Compound Test Format

A test chemical is assayed across 6 dose levels with concurrent zero-dose and positive controls, all performed in triplicate to provide statistical robustness. The test is operated both with and without S9 exogenous metabolism.


We provide two test options for our clients:


Genotypes and gene mutations of S. typhimurium and E. coli strains

StrainMutationReversion TypeCell WallRepairpKM101
TA100hisG46Base-pair substitutionrfauvrBYes
TA1535hisG46Base-pair substitutionrfauvrBNo
E. coli uvrAtrpE65Base-pair substitutionuvrANo