Lysis of growing cells ofSaccharomyces cerevisiae induced by papulacandin B

Light and electron microscopy was used to study the effect of papulacandin B onSaccharomyces cerevisiae in the exponential growth phase. At 1–2 μg/mL cell division in the culture continued almost in parallel with the control, at 4 μg/mL cell proliferation was reduced and the culture contained some cells with 2–9 buds which were not separated from the mother cell by a septum, and at higher concentrations (8, 16 and 32 μg/mL) the proliferation stopped within 2 h. Cessation of proliferation was due to lysis of budding cells in the bud region including perforation of thinned cell wall (most often at the bud basis and sometimes at its apex), extrusion of cytoplasm and death of cell. Lysis was also observed in cells without visible buds. Dividing cells died without visible lysis.