Metabolic adaptations to anoxia and reoxygenation: New lessons from freshwater turtles and crucian carp

Ruhr, I.M.; Bundgaard, A.; Fago, A.; Galli, G.L.J.

Abstract

As the final electron acceptor in the electron transport chain, oxygen is vital to produce ATP in the process of oxidative phosphorylation. In most vertebrates, the absence of oxygen (anoxia) quickly leads to an imbalance of ATP supply and demand and the activation of cell–death pathways. Remarkably, however, freshwater turtles of the genera Trachemys and Chrysemys, and fishes of the genus Carassius (crucian carp and the closely related goldfish) can survive in anoxic environments for periods lasting several months. While both species inhabit similar environments, they use very different strategies to survive oxygen deprivation. In this review, we focus on metabolic strategies and adaptations that allow these species to avoid, regulate, or mitigate the negative effects of anoxia and reoxygenation on cell function. Specifically, we review strategies to balance ATP supply and demand, the regulation of toxic end-products, mitochondrial remodelling, metabolite accumulation, regulation of reactive oxygen species, and Ca2+ management. Through the strategies they use, turtles and crucian carp are excellent model species to shed light on metabolic adaptations to anoxia and reveal novel drug targets for the treatment of oxygen-related diseases in humans.

• Journal Article Type: Review
• Online Publication Date: Jan 18, 2020
• Publication Date: Feb 17, 2020
• Deposit Date: Jun 11, 2025
• Journal: Current Opinion in Endocrine and Metabolic Research
• Electronic ISSN: 2451-9650
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Pages: 55-64
• DOI: https://doi.org/10.1016/j.coemr.2020.01.002