Cell Size Dependency of the Sporulation Process in the Yeast Saccharomyces cerevisiae

Summary: Physiological changes during the sporulation process were compared between large and small cells prepared from stationary phase cells of Saccharomyces cerevisiae. There were marked differences in the sporulation capacity between cells of different size. NH⁺₄ and methylamine did not block sporulation in large cells, but did in small cells. Large cells could sporulate in water without exposure to acetate sporulation medium, but small cells could not. During sporulation, small cells became insensitive to NH⁺₄ and methylamine and acquired the ability to sporulate in water at an early stage. After acquiring the ability to sporulate in water, sporulation in small cells proceeded through a series of physiological changes common to those occurring in large cells. These results suggested that the initiation point of sporulation varied with cell size.