Koziol Sabina, Zagulski Marek, Bilinski Tomasz, Bartosz Grzegorz
Department of Biochemistry and Cell Biology, University of Rzeszów, Rejtana 16C PL 35-959, Rzeszów, Poland.
Free Radic Res. 2005 Apr;39(4):365-71. doi: 10.1080/10715760500045855.
Yeast (Saccharomyces cerevisiae) mutants lacking CuZnSOD have been reported to be hypersensitive to hypertonic media and to show increased oxidative damage. This study demonstrates that hypertonic medium (containing 0.8 M NaCl) increases the generation of superoxide and other reactive species in yeast cells. Other sequelae of exposure to hypertonic medium include oxidation of cellular low-molecular weight thiols and decrease in total antioxidant capacity of cellular extracts. deltasod1 mutant is more sensitive than a wild-type strain to colony growth inhibition on a hypertonic medium. Anaerobic conditions, ascorbate, glutathione, cysteine and dithiothreitol are able to ameliorate this growth inhibition but a range of other antioxidants does not protect. The protective ability of the antioxidants does not correlate with the rate of their reactions with superoxide but seems to be conditioned by low redox potential for one-electron oxidation of free radicals of the antioxidants. It suggests that repair of low-redox potential targets rather than prevention of their damage by superoxide is important in the antioxidant protection against oxidative stress induced by hypertonic conditions.
据报道，缺乏铜锌超氧化物歧化酶（CuZnSOD）的酵母（酿酒酵母）突变体对高渗培养基高度敏感，并表现出氧化损伤增加。本研究表明，高渗培养基（含0.8 M氯化钠）会增加酵母细胞中超氧化物和其他活性物质的生成。暴露于高渗培养基的其他后果包括细胞低分子量硫醇的氧化以及细胞提取物总抗氧化能力的降低。与野生型菌株相比，deltasod1突变体在高渗培养基上对菌落生长抑制更为敏感。厌氧条件、抗坏血酸、谷胱甘肽、半胱氨酸和二硫苏糖醇能够改善这种生长抑制，但一系列其他抗氧化剂则没有保护作用。抗氧化剂的保护能力与其与超氧化物的反应速率无关，但其似乎取决于抗氧化剂自由基单电子氧化的低氧化还原电位。这表明，在针对高渗条件诱导的氧化应激的抗氧化保护中，修复低氧化还原电位靶点而非防止其被超氧化物损伤很重要。
