High-throughput and sensitive assay to measure yeast cell growth: a bench protocol for testing genotoxic agents.

Intracellular metabolites and environmental agents continuously challenge the structural integrity of DNA. In the yeast Saccharomyces cerevisiae, the complete collection of open reading frame deletion mutants, in combination with powerful screening methods, allows for the comprehensive analyses of cellular responses to insult. We have developed a protocol to determine the sensitivity of growing yeast to DNA-damaging agents that is based on automatic measurements of the optical density of very small (100 microl) liquid cultures. This simple method is highly sensitive, provides quantifiable data and offers high-throughput screening capability. Starting with the treatment of cells with different doses of damaging agents, pre-prepared growing media containing 96-well plates are inoculated and cell population is automatically monitored every 10 min for 48 hours. With the aid of a multi-channel pipette, the sensitivity of a number of yeast strains to several concentrations of drug can be tested in triplicate in less then 4 hours.