Reactive oxygen species (ROS) and the heat stress response of Daphnia pulex: ROS‐mediated activation of hypoxia‐inducible factor 1 (HIF‐1) and heat shock factor 1 (HSF‐1) and the clustered expression of stress genes

Heat stress evoked ROS fluctuations, with this stress signal forwarded via nHIF-1 and nHSF-1 fluctuations to stress gene expression. The frequency of ROS fluctuations seemed to integrate information about ROS productionrate and GSH antioxidant buffer capacity, resulting in stress protein expression of different speed. Results of this study suggest ROS as early (pre-damage) and protein defects as later (post-damage) stress signals to trigger heat stress responses.