Sugar-induced apoptosis in yeast cells.

Sugars induce death of Saccharomyces cerevisiae within a few hours in the absence of additional nutrients to support growth; by contrast, cells incubated in water or in the presence of other nutrients without sugar remain viable for weeks. Here we show that this sugar-induced cell death (SICD) is characterized by rapid production of reactive oxygen species (ROS), RNA and DNA degradation, membrane damage, nucleus fragmentation and cell shrinkage. Addition of ascorbic acid to sugar-incubated cells prevents SICD, indicating that SICD is initiated by ROS. The lack of a protection mechanism against SICD suggests that sugars use to be the limiting nutrients for yeast and are probably depleted before all other nutrients. Being the limiting nutrient, sugars became the growth-stimulating agent, signaling the presence of sufficient nutrients for growth, but in the absence of the complementing nutrients they induce apoptotic death.