The mortality of a population reflects the combined effects of natural aging with environmental insults (e.g. toxicant exposure, caloric restriction, over feeding, infections, etc.). No single endpoint, such as carcinogenesis, completely describes toxicant-induced effects in laboratory animals. Mathematical models of mortality and time-dependent exposure to toxicants can yield indices of net in...

Weed management systems in almost all Brazilian coffee plantations allow herbicide spray to drift on crop plants. In order to evaluate if there is any effect of the most commonly used herbicide in coffee production, glyphosate, on coffee plants, a range of glyphosate doses were applied directly on coffee plants at two distinct plant growth stages. Although growth of both young and old plants wa...

Several studies on the effect of inhaled plutonium-dioxide particulates and the incidence of lung tumors in dogs reveal beneficial effects when the cumulative alpha-radiation dose is low. There is a threshold at an exposure level of about 100 cGy for excess tumor incidence and reduced lifespan. The observations conform to the expectations of the radiation hormesis dose-response model and contra...

Hydrogen peroxide (H2O2) is a stable product of water radiolysis, occurring at nanomolar concentration upon low-dose ionizing radiation (LDIR) (<100 mGy). In view of the recent recognition of H2O2 as a central redox signaling molecule that, likewise, is maintained in the nanomolar range in cells, we propose a role for H2O2 in radiation hormesis. LDIR is capable of utilizing known molecular redo...

Hormesis is a biological phenomenon, whereby exposure to low levels of toxic agents or conditions increases organismal viability. It thus represents a beneficial aspect of adaptive responses to harmful environmental stimuli. Here we show that hormesis effects induced in the parental generation can be passed on to the descendants in Caenorhabditis elegans. Animals subjected to various stressors ...

Caloric restriction (CR) markedly extends the life of rats, mice and several other species, and it also modulates age-associated physiological deterioration and delays the occurrence and/or slows progression of age-associated diseases. The level of CR that retards the aging processes is a low-intensity stressor, which enhances the ability of rats and mice of all ages to cope with intense stress...