Hormesis provides a generalized quantitative estimate of biological plasticity

Abstract

Phenotypic plasticity represents an environmentallybased change in an organism's observable properties. Since biological plasticity is a fundamental adaptive feature, it has been extensively assessed with respect to its quantitative features and genetic foundations, especially within an ecological evolutionary framework. Toxicological investigations on the dose-response continuum (i.e., very broad dose range) that include documented evidence of the hormetic dose response zone (i.e., responses to doses below the toxicological threshold) can be employed to provide a quantitative estimate of phenotypic plasticity. The low dose hormetic stimulation is an adaptive response that reflects an environmentally-induced altered phenotype and provides a quantitative estimate of biological plasticity. Analysis of nearly 8,000 dose responses within the hormesis database indicates that quantitative features of phenotypic plasticity are highly generalizable, being independent of biological model, endpoint measured and chemical/physical stress inducing agent. The magnitude of phenotype changes indicative of plasticity is modest with maximum responses typically being approximately 30-60% greater than control values. The present findings provide the first quantitative estimates of biological plasticity and its capacity for generalization. Summary This article provides the first quantitative estimate of biological plasticity that may be generalized across plant, microbial, animal systems, and across all levels of biological organization. The quantitative features of plasticity are described by the hormesis dose response model. These findings have important biological, biomedical and evolutionary implications.

Lack of genotoxicity in Astyanax bimaculatus and Oreochromis niloticus of 17α-methyltestosterone used in fish hatcheries to produce male monosex populations

“…Exposure to MT at a low concentration may cause a direct stimulation of the receptor pathway, following its activation, and consequently cell disturbances. This could explain the results obtained in our study, where only the lowest concentration showed potential for genotoxicity compared to higher concentrations (Calabrese and Mattson, 2011). On the other hand, due to its rapid degradation in water, organisms are exposed only to low concentrations.…”

Adaptive Cellular Stress Pathways as Therapeutic Targets of Dietary Phytochemicals: Focus on the Nervous System

“…Exposure of cells and organisms to low doses of chemicals that are toxic at higher doses often triggers adaptive stress responses that can protect against higher doses of the same chemical and, importantly, a range of different stressors. This general biologic phenomenon, which is termed hormesis, is firmly engrained in the evolutionary history of all organisms (Calabrese et al, 2007;Mattson, 2008;Calabrese and Mattson, 2011). In some cases, organisms have even incorporated once-toxic environmental agents into their own macromolecules where they serve important functions.…”

Nonlinear Response Amplification Mechanisms for Low Doses of Natural Product Nanomedicines: Dynamical Interactions with the Recipient Complex Adaptive System

“…However, the direction of change from adaptation to a low dose that the organism can survive instead enhances resistance against the adverse effects of the same agent [97,98,[103][104][105]. Furthermore, such beneficial changes can modify responses to not only the same, but also a cross-adapted agent or stressor.…”

“…In hormesis, low doses of an agent or a different, cross-adapted agent can initiate beneficial adaptive responses that can either reverse existing toxicity or protect the organism against future higher (toxic) dose exposures [122]. More than 8,000 scientific papers have now demonstrated hormetic effects as a manifestation of biological plasticity [103]. Low doses of nanoparticles can cause hormesis [105,123].…”