caa a22 4500 465826687 CHVBK 20180323112151.0 cr unu---uuuuu 170327e19900701xx s 000 0 eng 10.1007/BF01075666 doi (NATIONALLICENCE)springer-10.1007/BF01075666 Hand Steven Department of Environmental, Population and Organismic Biology, University of Colorado, 80309-0334, Boulder, CO, USA aut Heat dissipation during long-term anoxia in Artemia franciscana embryos: identification and fate of metabolic fuels [Elektronische Daten] [Steven Hand] Summary: 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 O 2 -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 O 2 -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 inArtemia 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. Springer-Verlag, 1990 Anaerobic dormancy nationallicence Anoxia nationallicence Artemia nationallicence Calorimetry nationallicence Journal of Comparative Physiology B Springer-Verlag 160/4(1990-07-01), 357-363 0174-1578 160:4<357 1990 160 360 https://doi.org/10.1007/BF01075666 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01075666 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Hand Steven Department of Environmental, Population and Organismic Biology, University of Colorado, 80309-0334, Boulder, CO, USA aut NATIONALLICENCE 773 0- Journal of Comparative Physiology B Springer-Verlag 160/4(1990-07-01), 357-363 0174-1578 160:4<357 1990 160 360 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer