A new killer toxin produced by Saccharomyces cerevisiae

A wine-making Saccharomyces cerevisiae yeast strain isolated in our laboratory produces two different killer toxins, each one encoded by one dsRNA plasmid. One toxin has the same specificity as the one produced by strain M437 described by Naumov, but the dsRNA plasmid which encodes it migrates slightly faster in poly acrylamide gel electrophoresis. The other toxin has not been previously described, and is encoded by a dsRNA fraction which migrates at a lower rate than the × fraction of M437. These two dsRNA plasmids can be maintained separately in different yeast strains.