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AAT Bioquest

How is the Ames test performed?

Posted March 25, 2021


Answer

The Ames test is a bacterial assay used to determine a compound's mutagenicity by testing its capacity to revert mutations present in the tester mutant bacteria and restore its ability to synthesize an essential amino acid required for growth. The following is a simple protocol for the Ames test:

  • Isolate mutant strains of His- S. typhimurim.
  • Prepare a negative control suspension of His- S. typhimurim in a buffer.
  • Prepare a test suspension of His- S. typhimurim in a buffer supplemented with the test chemical and small amounts of histidine.
  • Incubate both suspensions at 37°C for 20 minutes.
  • Prepare two separate agar plates, pour suspension on two Petri plates, and spread using an L-shaped spreader. Cover the Petri plates with sterile aluminum foil to protect the testing sample from photoreactive substances.
  • Incubate plates for 48 hours at 37 °C.
  • After incubation, count the number of colonies on each plate.
Additional resources

The Salmonella (Ames) test for mutagenicity

Gelite™ Safe DNA Gel Stain