Institute of Zoophysiology, University of Münster, Hindenburgplatz 55, 48143 Münster, Germany.
Biol Cell. 2011 Aug;103(8):351-63. doi: 10.1042/BC20100145.
ROS (reactive oxygen species) as well as components of the antioxidant redox systems may act as signals. To link acute environmental change with gene expression, changes in ROS and GSH/GSSG (reduced/oxidized glutathione) level were measured upon acute changes in temperature or oxygen availability in the aquatic key species Daphnia magna together with HIF-1 (hypoxia-inducible factor 1)-mediated Hb (haemoglobin) expression.
Acute exposures to 30°C or hypoxia, which induced tissue hypoxia (and possibly elevated mitochondrial ROS production), caused resembling fluctuations of ROS and GSH levels, with frequency and number of peaks increasing and their delay decreasing with the magnitude of environmental change (size of tissue hypoxia). Acute hyperoxia induced an initial decrease in ROS level. Evidence is also provided for the promoting effects of ROS on catalase activity. A signalling function of the ROS fluctuations upon acute changes in temperature was found in the case of Hb, the expression of which is known to respond to temperature changes, by detecting corresponding time courses of both transcription and protein formation.
ROS-dependent signalling was affected by changes in temperature or oxygen availability. Feedback interactions between ROS and the glutathione redox system, possibly driven by elevated mitochondrial ROS production, likely contributed to the appearance of the ROS and GSH fluctuations upon acute environmental change. Fluctuating ROS levels, which reflect for the magnitude of environmental change, could be a way to transfer information on ROS production to subsequent processes (gene expression) while avoiding too-high and damaging ROS levels.
活性氧（reactive oxygen species，ROS）和抗氧化还原系统的成分可能作为信号发挥作用。为了将急性环境变化与基因表达联系起来，我们在水生关键物种大型溞（Daphnia magna）中测量了 ROS 和 GSH/GSSG（还原/氧化型谷胱甘肽）水平的变化，以及低氧诱导因子 1（hypoxia-inducible factor 1，HIF-1）介导的血红蛋白（haemoglobin，Hb）表达，以研究温度或氧气供应的急性变化对其产生的影响。
急性暴露于 30°C 或缺氧条件下会导致组织缺氧（并可能增加线粒体 ROS 产生），从而引起 ROS 和 GSH 水平的类似波动，其频率和峰值数量随环境变化幅度（组织缺氧程度）的增加而增加，且延迟时间减少。急性高氧会导致 ROS 水平的初始下降。研究还为 ROS 对过氧化氢酶活性的促进作用提供了证据。ROS 波动在急性温度变化对血红蛋白表达的影响中表现出信号功能，而血红蛋白的表达已知会对温度变化做出响应。我们通过检测转录和蛋白形成的相应时间过程，发现了这一情况。
ROS 依赖性信号受到温度或氧气供应变化的影响。ROS 和谷胱甘肽氧化还原系统之间的反馈相互作用，可能是由线粒体 ROS 产生增加驱动的，这可能是急性环境变化时 ROS 和 GSH 波动出现的原因。波动的 ROS 水平反映了环境变化的幅度，它可以作为一种将 ROS 产生信息传递给后续过程（基因表达）的方式，同时避免 ROS 水平过高和产生损伤。
