A New Killer Factor Produced by a Killer/Sensitive Yeast Strain

Abstract

Summary: The isolation of a new killer/sensitive phenotype of the yeast, Saccharomyces cerevisiae, is described. Killer/sensitive yeast cells are killed by the killer factor (KF1) secreted by killer yeast cells. The killer/sensitive cells also secrete a new killer factor (KF2) which kills sensitive cells. The production of KF2 by killer/sensitive cells renders them less sensitive to KF1, than sensitive cells. Sensitive cells are most susceptible to the action of KF2 in log phase. KF2 is a thermostable protein-containing killer factor.