Moraitis Christos, Curran Brendan P G
School of Biological and Chemical Sciences, Queen Mary College, University of London, Mile End Road, London E1 4NS, U.K.
Yeast. 2007 Aug;24(8):653-66. doi: 10.1002/yea.1498.
In this study we used a heat-shock (HS) reporter gene to demonstrate that respiring cells are intrinsically less sensitive (by 5 degrees C) than their fermenting counterparts to a sublethal heat shock. We also used an oxidant-sensitive fluorescent probe to demonstrate that this correlates with lower levels of sublethal reactive oxygen species (ROS) accumulation in heat-stressed respiring cells. Moreover, this relationship between HS induction of the reporter gene and ROS accumulation extends to respiring cells that have had their ROS levels modified by treatment with the anti-oxidant ascorbic acid and the pro-oxidant H(2)O(2). Thus, by demonstrating that the ROS/HSR correlation previously demonstrated in fermenting cells also holds for respiring cells (despite their greater HS insensitivity and higher level of intrinsic thermotolerance), we provide evidence that the intracellular redox state may influence both the sensitivity of the heat-shock response (HSR) and stress tolerance in the yeast Saccharomyces cerevisiae.
在本研究中，我们使用了一个热休克（HS）报告基因来证明，进行呼吸作用的细胞相较于进行发酵作用的细胞，在面对亚致死性热休克时，其内在敏感性要低5摄氏度。我们还使用了一种对氧化剂敏感的荧光探针来证明，这与热应激条件下进行呼吸作用的细胞中亚致死性活性氧（ROS）积累水平较低相关。此外，报告基因的HS诱导与ROS积累之间的这种关系，也适用于那些通过抗氧化剂抗坏血酸和促氧化剂H₂O₂处理而改变了ROS水平的进行呼吸作用的细胞。因此，通过证明先前在发酵细胞中所证实的ROS/HSR相关性在进行呼吸作用的细胞中同样成立（尽管它们对HS的敏感性较低且内在耐热性水平较高），我们提供了证据表明细胞内氧化还原状态可能会影响酿酒酵母中热休克反应（HSR）的敏感性和应激耐受性。
