Mini mutagenicity test: a miniaturized version of the Ames test used in a prescreening assay for point mutagenesis assessment

The bacterial reverse mutagenicity test on Salmonella typhimurium, known as the Ames test, is widely used by regulatory agencies, academic institution s and chemical companies to assess the mutagenic potential of raw compounds . Several attempts have been made to miniaturise the Ames test in order to fit the industrial constraint of screening more products at the low quantit ies available. The major limitation of these miniaturised versions of the A mes test lies in the impossibility to work with all the six strains used in the regular Ames test, especially with those showing a low spontaneous rev ertant frequency. We describe here a mini version of the regulatory Ames te st protocol that allows 3 significant reduction of the quantity of test sub stance needed (300 mg) but remains applicable to all Salmonella strains use d in the regulatory protocol. In a preliminary study, 10 in-house chemical compounds have been evaluated in the Mini Mutagenicity Test (MMT) together with some positive control substances. A first set of historical data obtai ned in 1999 as well as the predictivity and the sensitivity of the MMT are presented and compared to those of the regular Ames test. (C) 2001 Elsevier Science Ltd. All rights reserved.