Granot David, Levine Alex, Dor-Hefetz Edan
Institute of Field and Garden Crops, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet-Dagan 50250, Israel.
FEMS Yeast Res. 2003 Oct;4(1):7-13. doi: 10.1016/S1567-1356(03)00154-5.
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.
在缺乏支持生长的其他营养物质的情况下，糖在数小时内就能诱导酿酒酵母死亡；相比之下，在水中或存在其他营养物质但无糖的情况下培养的细胞能存活数周。我们在此表明，这种糖诱导的细胞死亡（SICD）的特征是活性氧（ROS）的快速产生、RNA和DNA降解、膜损伤、细胞核碎片化和细胞收缩。向糖处理的细胞中添加抗坏血酸可防止SICD，这表明SICD是由ROS引发的。缺乏针对SICD的保护机制表明，糖过去是酵母的限制性营养物质，并且可能在所有其他营养物质耗尽之前就已耗尽。作为限制性营养物质，糖成为生长刺激剂，表明存在足够的生长营养物质，但在缺乏互补营养物质的情况下，它们会诱导细胞凋亡死亡。
