Energetics of anoxia exposure and recovery as assessed by calorimetry and biochemical measurements
Abstract
Some invertebrates enter quiescent metabolic states and survive extended bouts of severe hypoxia or anoxia (on the order of weeks to months). This strategy of metabolic suppression requires a coordinated arrest of both catabolic and anabolic components of energy metabolism. For embryos of the brine shrimp Artemia franciscana, calorimetry shows that energy flow under anoxia is suppressed to exceedingly low levels. Anabolic processes such as protein synthesis are also acutely arrested under anoxia in these embryos. The half-lives of macromolecules, based on evidence for cytochrome c oxidase, are extended dramatically. Recovery from anoxia is characterized by a biphasic rise in heat and oxygen consumption. Biochemical measurements suggest that aerobic processing of organic acids occurs during the first 20 min of recovery, supporting the early rise in heat dissipation and contributing to the recovery of adenylate pools. © 1993 IUPAC