The Ames MPF and Ames II assays are modified versions of the Ames test using liquid culture instead of agar plates. The assays are based on the fluctuation method cited in OECD Guidline 471 but use 384-well microtiter plates and have a colorimetric read-out. The great advantage of this format is the lower amount of sample needed and much easier handling. The Ames MPF assays use TA98 and/or TA100, TA1535, TA1537. All these test strains are recommended in the current, formal test guidelines.
The Ames II assay differs from the Ames MPF assays in that it comprises TA98 and TAMix, consisting of 6 histidine mutant Salmonella tester strains, TA7001-TA7006. Each of these mutants can be reverted only by a specific transition or transversion, so that all possible base-pair changes can be detected by TAMix. The TA700x tester strains are not included among the recommended tester strains in the current, formal test guidelines.
Xenometrix offers practical training and in-house testing of the Ames MPF and Ames II assays in its facilities in Allschwil.