To explore the cytotoxicity of heavy metal cadmium(Cd)pollution and the breeding of Cd hyperaccumulation microorganisms,the model organism Saccharomyces cerevisiae was used as the cell model to investigate the target of cytotoxicity caused by Cd stress and the effect of overexpression of related genes on cell resistance.The mechanism of Cd toxicity was explored by analyzing the growth inhibition of mutant strains,the measurement of intracellular reactive oxygen species(ROS),and lipid peroxidation(MDA)levels under Cd stress.The effects of Cd on intracellular Na/K ion balance,membrane lipid composition,and cell wall structure were detected using ICP-AES,GC-MS,and scanning electron microscopy.The mutations in genes MGA2,PAH1,and CHS1 that affect membrane lipid synthesis and cell wall integrity were sensitive to Cd,and the levels of intracellular ROS and MDA increased with the increase of Cd concentration.Cd stress disrupted cell Na/K ion balance,affected cell lipid metabolism,increased palmitic acid and decreased oleic acid,and raised the rate of cell wall damage.Overexpression of the critical gene CHS2 for chitin synthesis was beneficial for maintaining the integrity of the cell wall,thus improving cell resistance to Cd.The plasma membrane and cell wall are the most crucial targets of Cd stress.The results provide a theoretical basis for the biological management of Cd pollution.
关键词
镉胁迫/重金属污染/酿酒酵母/细胞膜/细胞壁
Key words
cadmium stress/heavy metal pollution/Saccharomyces cerevisiae/cell plasma membrane/cell wall
维普
万方数据