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 Greekἐναντίος (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]
Estuarine environmentsedit
Examples of organisms which undergo enantiostasis in an estuarine environment include:
The oxygen binding effectiveness of hemocyanin in the blue crab Callinectes sapidus varies according to the concentration of two factors, calcium ion concentration, and hydrogen ion concentration. When these concentrations are varied in the same direction, they have a counterbalancing effect. To stabilize oxygen binding at low ionic concentrations, the crab increases its internal pH (decreasing the hydrogen ion concentration) to allow the hemocyanin to continue to function efficiently.[5]
The Dungeness crab, Cancer magister, relies on the magnesium ion (Mg2+) for its hemocyanin oxygen affinity. In the juvenile stage, the crab has higher magnesium ion concentrations resulting in higher hemocyanin oxygen affinity. This changes throughout development, such that the adult Cancer magister has less magnesium ion and thus, less hemocyanin oxygen affinity. Intrinsic oxygen affinity is inversely proportional magnesium ion concentrations in the crab, which counterbalances the hemocyanin oxygen affinity.[6]
High-salt environmentsedit
Halophiles have adapted to high salt environments by using energy from the sun to maintain a high internal potassium ion concentration and by using biological proteins that can function in the varying, high internal potassium ion concentrations. These adaptions allow halophiles to thrive by increasing internal osmolarity to compensate for the high sodium concentrations of the external environment,[7] which prevents the movement of water out of the cell.[8]
Referencesedit
^. Archived from the original on 2008-07-29. Retrieved 2008-06-13.
^Yan, Chong Chao (1996). "Effects of Taurine and Guanidinoethane Sulfonate on Toxicity of the Pyrrolizidine Alkaloid Monocrotaline". Biochemical Pharmacology. 51 (3): 321–329. doi:10.1016/0006-2952(95)02185-X. ISSN 0006-2952. PMID 8573199.
^C. P. Mangum & D. W. Towle (1977). "Physiological adaptation to unstable environments". American Scientist. 65 (1): 67–75. Bibcode:1977AmSci..65...67M. PMID 842933.
^ abReyes-DelaTorre, Alejandro; Teresa, Maria; Rafael, Juan (2012). "Carbohydrate Metabolism in Drosophila: Reliance on the Disaccharide Trehalose". Carbohydrates - Comprehensive Studies on Glycobiology and Glycotechnology. InTech. doi:10.5772/50633. ISBN978-953-51-0864-1.
^Charlotte P. Mangum (1997). "Adaptation of the oxygen transport system to hypoxia in the blue crab, Callinectes sapidus". American Zoologist. 37 (6): 604–611. doi:10.1093/icb/37.6.604.
^Terwilliger, Nora B.; Ryan, Margaret (2001-10-01). "Ontogeny of Crustacean Respiratory Proteins". American Zoologist. 41 (5): 1057–1067. doi:10.1093/icb/41.5.1057. ISSN 1540-7063.
^Roberts, Mary F (2005-08-04). "Organic compatible solutes of halotolerant and halophilic microorganisms". Saline Systems. 1: 5. doi:10.1186/1746-1448-1-5. ISSN 1746-1448. PMC1224877. PMID 16176595.
^Rippon, John W. (2015-01-07). "Biochemical Adaptation by Peter W. Hochachka and George N. Somero (review)". Perspectives in Biology and Medicine. 29 (2): 326–327. doi:10.1353/pbm.1986.0035. ISSN 1529-8795.
January 01, 1970
enantiostasis, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, 2011, learn,. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Enantiostasis news newspapers books scholar JSTOR May 2011 Learn how and when to remove this message 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 ἐnantios enantio opposite opposing over against and stasis stasis to stand posture Contents 1 Trehalose 2 Estuarine environments 3 High salt environments 4 ReferencesTrehalose editFruit 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 Estuarine environments editExamples of organisms which undergo enantiostasis in an estuarine environment include The oxygen binding effectiveness of hemocyanin in the blue crab Callinectes sapidus varies according to the concentration of two factors calcium ion concentration and hydrogen ion concentration When these concentrations are varied in the same direction they have a counterbalancing effect To stabilize oxygen binding at low ionic concentrations the crab increases its internal pH decreasing the hydrogen ion concentration to allow the hemocyanin to continue to function efficiently 5 The Dungeness crab Cancer magister relies on the magnesium ion Mg2 for its hemocyanin oxygen affinity In the juvenile stage the crab has higher magnesium ion concentrations resulting in higher hemocyanin oxygen affinity This changes throughout development such that the adult Cancer magister has less magnesium ion and thus less hemocyanin oxygen affinity Intrinsic oxygen affinity is inversely proportional magnesium ion concentrations in the crab which counterbalances the hemocyanin oxygen affinity 6 High salt environments editHalophiles have adapted to high salt environments by using energy from the sun to maintain a high internal potassium ion concentration and by using biological proteins that can function in the varying high internal potassium ion concentrations These adaptions allow halophiles to thrive by increasing internal osmolarity to compensate for the high sodium concentrations of the external environment 7 which prevents the movement of water out of the cell 8 References edit HSC Online Archived from the original on 2008 07 29 Retrieved 2008 06 13 Yan Chong Chao 1996 Effects of Taurine and Guanidinoethane Sulfonate on Toxicity of the Pyrrolizidine Alkaloid Monocrotaline Biochemical Pharmacology 51 3 321 329 doi 10 1016 0006 2952 95 02185 X ISSN 0006 2952 PMID 8573199 C P Mangum amp D W Towle 1977 Physiological adaptation to unstable environments American Scientist 65 1 67 75 Bibcode 1977AmSci 65 67M PMID 842933 a b Reyes DelaTorre Alejandro Teresa Maria Rafael Juan 2012 Carbohydrate Metabolism in Drosophila Reliance on the Disaccharide Trehalose Carbohydrates Comprehensive Studies on Glycobiology and Glycotechnology InTech doi 10 5772 50633 ISBN 978 953 51 0864 1 Charlotte P Mangum 1997 Adaptation of the oxygen transport system to hypoxia in the blue crab Callinectes sapidus American Zoologist 37 6 604 611 doi 10 1093 icb 37 6 604 Terwilliger Nora B Ryan Margaret 2001 10 01 Ontogeny of Crustacean Respiratory Proteins American Zoologist 41 5 1057 1067 doi 10 1093 icb 41 5 1057 ISSN 1540 7063 Roberts Mary F 2005 08 04 Organic compatible solutes of halotolerant and halophilic microorganisms Saline Systems 1 5 doi 10 1186 1746 1448 1 5 ISSN 1746 1448 PMC 1224877 PMID 16176595 Rippon John W 2015 01 07 Biochemical Adaptation by Peter W Hochachka and George N Somero review Perspectives in Biology and Medicine 29 2 326 327 doi 10 1353 pbm 1986 0035 ISSN 1529 8795 Retrieved from https en wikipedia org w index php title Enantiostasis amp oldid 1212615674, wikipedia, wiki, book, books, library,
