Ames variant

Ames BN, Elson-Schwab I, and Silver EA (2002) High dose vitamin therapy stimulates variant enzymes with decreased coenzyme binding affinity (increased Km) relevance to genetic disease and polymorphisms. American Journal of Clinical Nutrition 75, 616-58. 

The mutagenic activity of chemical substances can be assessed by means of the Ames test [109]. In analogy to this test which is based on the reversion of certain changes in the phenotype of mutants caused by the mutagen, one can use the reversion of a dark variant of Photobacterium leiognathi to the luminous one by mutagens, such as mitomycin C. This can be detected in nanogram amounts [110]. 

---