Assay for Spore Wall Integrity Using a Yeast Predator

During the budding yeast life cycle, a starved diploid cell undergoes meiosis followed by production of four haploid spores, each surrounded by a spore wall. The wall allows the spores to survive in harsh environments until conditions improve. Spores are also more resistant than vegetative cells to treatments such as ether vapor, glucanases, heat shock, high salt concentrations, and exposure to high or low pH, but the relevance of these treatments to natural environmental stresses remains unclear. This protocol describes a method for assaying the yeast spore wall under natural environmental conditions by quantifying the survival of yeast spores that have passed through the digestive system of a yeast predator, the fruit fly.