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MedLine Citation:
PMID:  23143920     Owner:  NLM     Status:  Publisher    
The Arctic springtail, Megaphorura arctica, survives sub-zero temperatures in a dehydrated state via trehalose-dependent cryoprotective dehydration. Regulation of trehalose biosynthesis is complex; based in part on studies in yeast and fungi, its connection with oxidative stress caused by exposure of cells to oxidants, such as hydrogen peroxide (H(2) O(2) ), or dehydration, is well documented. In this respect, we measured the amount of H(2) O(2) and antioxidant enzyme activities (superoxide dismutases: copper, zinc-CuZnSOD and manganese containing-MnSOD, and catalase-CAT), as the regulatory components determining H(2) O(2) concentrations, in Arctic springtails incubated at 5 °C (control) versus -2 °C (threshold temperature for trehalose biosynthesis). Because ecdysone also stimulates trehalose production in insects and regulates the expression of genes involved in redox homeostasis and antioxidant protection in Drosophila, we measured the levels of the active physiological form of ecdysone-20-hydroxyecdysone (20-HE). Significantly elevated H(2) O(2) and 20-HE levels were observed in M. arctica incubated at -2 °C, supporting a link between ecdysone, H(2) O(2) , and trehalose levels during cryoprotective dehydration. CAT activity was found to be significantly lower in M. arctica incubated at -2 °C versus 5 °C, suggesting reduced H(2) O(2) breakdown. Furthermore, measurement of the free radical composition in Arctic springtails incubated at 5 °C (controls) versus -2 °C by Electron Paramagnetic Resonance spectroscopy revealed melanin-derived free radicals at -2 °C, perhaps an additional source of H(2) O(2) . Our results suggest that H(2) O(2) and ecdysone play important roles in the cryoprotective dehydration process in M. arctica, linked with the regulation of trehalose biosynthesis.
Gordana Grubor-Lajšić; Edward T Petri; Danijela Kojić; Jelena Purać; Zeljko D Popović; Roger M Worland; Melody S Clark; Miloš Mojović; Duško P Blagojević
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-11-12
Journal Detail:
Title:  Archives of insect biochemistry and physiology     Volume:  -     ISSN:  1520-6327     ISO Abbreviation:  Arch. Insect Biochem. Physiol.     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-12     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8501752     Medline TA:  Arch Insect Biochem Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2012 Wiley Periodicals, Inc.
Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Republic of Serbia.
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