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Difference between revisions of "Hand 1990 J Comp Physiol B"

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Revision as of 08:50, 14 November 2011

Publications in the MiPMap
Hand SC (1990) Heat dissipation during long-term anoxia in Artemia franciscana embryos: identification and fate of metabolic fuels. J. Comp. Physiol. B160: 357-363.

» PMID: 2292613

Hand SC (1990) J. Comp. Physiol. B

Abstract: Microcalorimetric measurements of brine shrimp embryos during 6 days of anoxia indicated that heat dissipation was rapidly suppressed to 2.7% of control (aerobic) values over the first 9 h. Energy flow continued to decline slowly to 31 µW·g dry mass-1 (0.4% of control) during the subsequent 5.5 days. Within 2 h after returning anoxic embryos to aerobic conditions, heat dissipation rose to 77% of control rates. The calorimetric/respirometric (CR) ratio across this 2-h recovery period increased steadily from-226 to-346 kJ·mol O2 -1 . Prior to the anoxic exposures, hydrated embryos were incubated aerobically for 10 h to insure full initiation of carbohydrate metabolism (CR ratio=-484 kJ·mol O2 -1 ). During the 6-day asymptotic approach to a nearly ametabolic state, trehalose and glycogen levels declined 18% and 13%, respectively. The majority of this utilization occurred within the first three days. Thermochemical calculations showed that carbohydrate catabolism accounted for 84% of the total heat dissipation measured over the 6-day anoxic bout; only 3% of the heat could be explained by the catabolism of diguanosine tetraphosphate (Gp4G). Analyses of embryo extracts by high performance liquid chromatography indicated that multiple acid end products were accumulated. Lactate and propionate reached 4.5 mM and 1.0 mM, respectively, but these compounds did not account quantitatively for the amount of carbohydrate utilized. However, the largest chromatographic peak that accumulated under anoxia has not been successfully identified. Fumarate and pyruvate levels decreased as anoxia proceeded. Thus, a perceptible energy flow in Artemia franciscana embryos still remained after 6 days of anoxia. While an ametabolic state may be reached with time, the length of this prolonged transition into anaerobic dormancy has not been appreciated before. Keywords: Twin-Flow, Anaerobic dormancy, Anoxia, Artemia, Calorimetry

O2k-Network Lab: US_LA Baton Rouge_Hand SC


Labels:

Stress:Hypoxia  Organism: Other Non-Mammal"Other Non-Mammal" is not in the list (Human, Pig, Mouse, Rat, Guinea pig, Bovines, Horse, Dog, Rabbit, Cat, ...) of allowed values for the "Mammal and model" property. 

Preparation: Intact Organism"Intact Organism" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property. 

Regulation: Aerobic and Anaerobic Metabolism"Aerobic and Anaerobic Metabolism" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property. 



Twin-Flow