Enantiostasis
From Wikipedia, the free encyclopedia
Enantiostasis is the ability of an open system, especially a living organism, to maintain and conserve its metabolic and physiological functions in response to variations in an unstable environment. Estuarine organisms typically undergo enantiostasis in order to survive with constantly changing salt concentrations. The Australian NSW Board of Studies defines the term in its Biology syllabus as "the maintenance of metabolic and physiological functions in response to variations in the environment".[1]
Enantiostasis is not a form of classical homeostasis, meaning "standing at a similar level," which focuses on maintenance of internal body conditions such as pH, oxygen levels, and ion concentrations. Rather than maintaining homeostatic (stable ideal) conditions, enantiostasis involves maintaining only functionality in spite of external fluctuations. However, it can be considered a type of homeostasis in a broader context because functions are kept relatively consistent. Organic compounds such as Taurine have been shown to still properly function within environments that have been disrupted from an ideal state.[2]
The term enantiostasis was proposed by Mangum and Towle.[3] It is derived from the Greek ἐναντίος (enantio-; opposite, opposing, over against) and στάσις (stasis; to stand, posture).
- Fruit flies (Drosophila) use the non-toxic sugar trehalose that is found in the hemolymph of insects to cope with changes in environmental conditions. Trehalose levels can spike up to 2% in the hemolymph in response to temperature changes, salinity and osmotic and oxidative stress.[4]
- Yeast cells accumulate trehalose in order to withstand heat stress.[4]