Assessment of Cyto‐ and Genotoxic Effects of a Variety of Chemicals Using Saccharomyces cerevisiae

Saccharomyces cerevisiae as the most simple eukaryotic organism is broadly accepted as a laboratory model organism. For the detection of potential toxic effects of pure compounds and complex composed samples like wastewater a miniaturised short‐term in vitro cyto‐ and genotoxicity screening assay was developed. The assay based on genetically modified S. cerevisiae cells deleted in the prominent drug efflux transporters Pdr5, Snq2, and Yor1 that facilitate pleiotropic drug resistance. The yeast strain devoid of these proteins that mediate the efflux of structurally diverse hydrophobic compounds exhibited an increased sensitivity to a variety of organic compounds. The DNA damage inducible RAD54 promoter fused to a yeast optimized derivative of the GFP (green fluorescent protein) gene from the jelly fish Aequorea victoria served as an indicator of DNA damage in this strain. Various pure compounds including the direct‐acting genotoxins methyl‐N‐nitro‐N‐nitrosoguanidine (MNNG), 4‐nitroquinoline‐N‐oxide (4‐NQO), methyl methanesulfonate (MMS) and hydroxyurea as well as the heavy metals cadmium and chromium(VI), the insecticide lindane and the central nervous system stimulant caffeine were tested exhibiting dose dependent induction of green fluorescence. All compounds were in parallel examined for chronic toxicity. A bioassay detecting simultaneously geno‐ and cytotoxic effects of potential toxicants in a single assay can be an important tool with a variety of applications in environmental monitoring and aquatic ecotoxicology. By partial automation and miniaturisation to microtitration scale this bioassay enables sensitive and fast biomonitoring for a multitude of samples.