Multiple Stressors in Caenorhabditis elegans Induce Stress Hormesis and Extended Longevity

Abstract

We demonstrate here that the nematode Caenorhabditis elegans displays broad hormetic abilities. Hormesis is the induction of beneficial effects by exposure to low doses of otherwise harmful chemical or physical agents. Heat as well as pretreatment with hyperbaric oxygen or juglone (a chemical that generates reactive oxygen species) significantly increased subsequent resistance to the same challenge. Cross-tolerance between juglone and oxygen was also observed. The same heat or oxygen pretreatment regimens that induced subsequent stress resistance also increased life expectancy and maximum life span of populations undergoing normal aging. Pretreatment with ultraviolet or ionizing radiation did not promote subsequent resistance or increased longevity. In dose-response studies, induced thermotolerance paralleled the induced increase in life expectancy, which is consistent with a common origin.

Heat Shock and Caloric Restriction Have a Synergistic Effect on the Heat Shock Response in a sir2.1-dependent Manner in Caenorhabditis elegans

“…A characteristic of many HSR activators is the ability to elicit hormesis, a biological process that occurs when a low level stress is applied that promotes cytoprotection against a subsequent exposure to a more severe stress (8). For instance, exposure to a moderate heat shock (HS) can protect against exposure to a subsequent high temperature HS in Caenorhabditis elegans (9).…”

Milieu-Dependent Pro- and Antioxidant Activity of Juglone May Explain Linear and Nonlinear Effects on Seedling Development

“…This also reflects a mitigating effect on the stress when the seeds were exposed to high methanol concentrations. Cypser and Johnson (2002) observed a similar hormetic effect of juglone in gerontological studies that used the nematode C. elegans as a test organism. In that study, pretreatment with the toxin juglone mitigated oxygen stress.…”

“…We expected to detect nonlinear effects (hormesis) at higher methanol levels. Hormetic abilities previously have been reported for effects of juglone on the genetic model nematode Caenorhabditis elegans; these effects became especially evident when C. elegans was pretreated with low dosages of heat, hyperbaric oxygen, or even juglone itself, and then subjected to subsequent stresses of the original or one of the other stressors (Cypser and Johnson 2002).…”

New links between protein N-terminal acetylation, dauer diapause, and the insulin/IGF-1 signaling pathway inCaenorhabditis elegans

“…For example, prior exposure to a mild heat shock causes increased resistance to a major heat shock, and animals that experienced the mild heat shock survive better than control animals kept in benign conditions. 15 The second model is that the gene promotes an activity that causes vulnerability to stress. An example of this is histidine ammonia lyase (haly-1), a gene that encodes an enzyme that metabolizes histidine.…”