Department of Biochemistry and Biotechnology, Vassyl Stefanyk Precarpathian National University, Ukraine.
Dose Response. 2013 Jun 4;12(1):93-109. doi: 10.2203/dose-response.13-013.Bayliak. eCollection 2014 Jan.
Concentration-dependent effects of aqueous extract from R. rosea root on long-term survival and stress resistance of budding yeast Saccharomyces cerevisiae were studied. At low concentrations, R. rosea aqueous extract extended yeast chronological lifespan, enhanced oxidative stress resistance of stationary-phase cells and resistance to number stressors in exponentially growing cultures. At high concentrations, R. rosea extract sensitized yeast cells to stresses and shortened yeast lifespan. These biphasic concentration-responses describe a common hormetic phenomenon characterized by a low-dose stimulation and a high-dose inhibition. Yeast pretreatment with low doses of R. rosea extract enhanced yeast survival and prevented protein oxidation under H2O2-induced oxidative stress. Positive effect of R. rosea extract on yeast survival under heat shock exposure was not accompanied with changes in antioxidant enzyme activities and levels of oxidized proteins. The deficiency in transcriptional regulators, Msn2/Msn4 and Yap1, abolished the positive effect of low doses of R. rosea extract on yeast viability under stress challenges. Potential involvement of Msn2/Msn4 and Yap1 regulatory proteins in realization of R. rosea beneficial effects is discussed.
研究了西洋蒲公英根水提物对出芽酵母酿酒酵母长期生存和抗应激能力的浓度依赖性影响。在低浓度下，西洋蒲公英水提物延长了酵母的时序寿命，增强了静止期细胞的氧化应激抗性和指数生长期对多种应激源的抗性。在高浓度下，西洋蒲公英提取物使酵母细胞对胁迫敏感并缩短了酵母寿命。这些两相浓度反应描述了一种常见的兴奋效应现象，其特征是低剂量刺激和高剂量抑制。用低剂量西洋蒲公英提取物预处理酵母可增强酵母在过氧化氢诱导的氧化应激下的存活并防止蛋白质氧化。西洋蒲公英提取物在热休克暴露下对酵母存活的积极影响并未伴随抗氧化酶活性和氧化蛋白水平的变化。转录调节剂 Msn2/Msn4 和 yap1 的缺失消除了低剂量西洋蒲公英提取物在应激挑战下对酵母活力的积极影响。讨论了 Msn2/Msn4 和 yap1 调节蛋白在实现西洋蒲公英有益效果中的潜在作用。
