Document Detail


Living without oxygen: lessons from the freshwater turtle.
MedLine Citation:
PMID:  10794959     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Freshwater turtles, and specifically, painted turtles, Chrysemys picta, are the most anoxia-tolerant air-breathing vertebrates. These animals can survive experimental anoxic submergences lasting up to 5 months at 3 degrees C. Two general integrative adaptations underlie this remarkable capacity. First is a profound reduction in energy metabolism to approximately 10% of the normoxic rate at the same temperature. This is a coordinated reduction of both ATP generating mechanisms and ATP consuming pathways of the cells. Second is a defense of acid-base state in response to the extreme lactic acidosis that results from anaerobic glycolysis. Central to this defense is an exploitation of buffer reserves within the skeleton and, in particular, the turtle's shell, its most characteristic structure. Carbonates are released from bone and shell to enhance body fluid buffering of lactic acid and lactic acid moves into shell and bone where it is buffered and stored. The combination of slow metabolic rate and a large and responsive mineral reserve are key to this animal's extraordinary anaerobic capacity.
Authors:
D C Jackson
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Review    
Journal Detail:
Title:  Comparative biochemistry and physiology. Part A, Molecular & integrative physiology     Volume:  125     ISSN:  1095-6433     ISO Abbreviation:  Comp. Biochem. Physiol., Part A Mol. Integr. Physiol.     Publication Date:  2000 Mar 
Date Detail:
Created Date:  2000-08-10     Completed Date:  2000-08-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9806096     Medline TA:  Comp Biochem Physiol A Mol Integr Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  299-315     Citation Subset:  IM    
Affiliation:
Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Box G, Providence, RI 02912, USA. donald_jackson@brown.edu
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MeSH Terms
Descriptor/Qualifier:
Acid-Base Equilibrium
Adaptation, Physiological
Animals
Anoxia*
Oxygen / metabolism,  physiology*
Turtles / metabolism,  physiology*
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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