吴丽华,陈燕飞,仪慧兰,乔宏萍,赵文婧.氧化胁迫参与硫酸锌诱导的酵母细胞死亡[J].环境科学学报,2019,39(9):3188-3194
氧化胁迫参与硫酸锌诱导的酵母细胞死亡
- Oxidative stress contributes to zinc sulfate-induced cell death in yeast
- 基金项目：国家自然科学基金（No.21307087）；山西省应用基础研究计划项目（No.201601D021104）
- 摘要：以模式生物酵母为材料，研究了不同浓度硫酸锌对酵母细胞的致死效应，以及活性氧（ROS）在硫酸锌诱导酵母凋亡中的作用.结果显示，低浓度处理组中，酵母细胞的相对生长率、超氧化物歧化酶活性和总抗氧化能力升高，超氧化物歧化酶相关基因SOD1和SOD2表达增强，而细胞存活率和MDA含量无明显变化.高浓度（3和5 mmol·L-1）处理组中，野生株酵母超氧化物歧化酶活性和总抗氧化能力明显下降，SOD1和SOD2基因表达受到明显抑制，胞内ROS水平和MDA含量升高，细胞死亡率显著上升；在相同锌处理组中，突变体ΔSOD1对硫酸锌的耐受性明显差于野生株BY4741，ΔSOD1胞内ROS水平和细胞凋亡率显著高于野生株，而ΔSOD2与野生株间无显著差异.结果表明，低浓度硫酸锌可促进酵母细胞生长，可能诱导了酵母细胞生长的Hormesis效应；高浓度硫酸锌可引起酵母细胞氧化损伤，而锌胁迫诱导的胞内ROS水平升高是酵母细胞死亡的一个诱因.该研究结果可为锌化物的毒性作用及其健康风险评估提供理论依据.
- Abstract：In this study, yeast was used as a model organism to understand the lethal effects of zinc sulfate at various concentrations on the cells and to investigate the role of reactive oxygen species (ROS) in zinc sulfate-induced apoptosis. The results showed that the low concentration treatment groups exhibited an increase in the relative growth rate, superoxide dismutase activity, and the total antioxidant capacity. Additionally, the expression of superoxide dismutase genes, SOD1 and SOD2, was enhanced, whereas cell viability and malondialdehyde (MDA) content did not change significantly. In the high concentration (3 and 5 mmol·L-1) treatment groups, the superoxide dismutase activity and the total antioxidant capacity of the wild-type yeast significantly decreased. Besides, the expression of SOD1 and SOD2 genes was significantly inhibited, and the levels of intracellular ROS and MDA were elevated. Additionally, the cell mortality rate increased significantly. In the same treatment groups, the tolerance of the ΔSOD1 mutant towards zinc sulfate was significantly lower than that of the BY4741 wild-type strain. The intracellular ROS levels and cell mortality of the ΔSOD1 mutant were particularly higher than those of the wild-type strain. However, no remarkable difference was noted between the ΔSOD2 mutant and the wild-type strain. Thus, the results demonstrated that zinc sulfate at low concentrations could induce a hermetic effect on yeast cell growth, whereas high concentrations of zinc sulfate could lead to oxidative damage in yeast cells, and zinc sulfate-induced intracellular ROS elevation is one of the contributors to yeast cell death. The information discussed above provides evidence for assessing the toxic effects and health risk estimation of zinc in the environment.
