Circadian regulation of abiotic stress tolerance in Caenorhabditis elegans

Circadian rhythms are ubiquitously found in nature. These rhythms are generated and sustained by a conserved time-keeping system that coordinates the biochemistry, physiology and behavior of an organism with daily changes in the environment. There is increasing evidence that this coordination contributes to the overall health of organisms. Hence, it is of great importance to understand how the circadian clock is able to transduce environmental signals to internal processes. One of the outputs of the circadian system in invertebrates, vertebrates, bacteria and plants is the stress resistance behavior. In this work we focus on the circadian variation in tolerance to several abiotic stressors in the nematode Caenorhabditis elegans. Circadian and daily variations in response to osmotic-, oxidative- and cyanide-mediated stress have been described at the behavioral and molecular level. Overall, the biological clock helps C. elegans cope with naturally occurring rhythms in abiotic stressors present in its natural habitat. It provides tools for preparing the organism to defend itself by predicting when the defense mechanisms are most needed.