Bundgaard 2020 J Exp Biol

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Bundgaard A, Qvortrup K, Rasmussen LJ, Fago A (2020) Turtles maintain mitochondrial integrity but reduce mitochondrial respiratory capacity in the heart after cold acclimation and anoxia. J Exp Biol 222:jeb200410.

» PMID: 31097599 Open Access

Bundgaard Amanda, Qvortrup Klaus, Rasmussen Lene Juel, Fago Angela (2020) J Exp Biol

Abstract: Mitochondria are important to cellular homeostasis, but can become a dangerous liability when cells recover from hypoxia. Anoxia-tolerant freshwater turtles show reduced mitochondrial respiratory capacity and production of reactive oxygen species (ROS) after prolonged anoxia, but the mechanisms are unclear. Here, we investigated whether this mitochondrial suppression originates from downregulation of mitochondrial content or intrinsic activity by comparing heart mitochondria from (1) warm (25°C) normoxic, (2) cold-acclimated (4°C) normoxic and (3) cold-acclimated anoxic turtles. Transmission electron microscopy of heart ventricle revealed that these treatments did not affect mitochondrial volume density and morphology. Furthermore, neither enzyme activity, protein content nor supercomplex distribution of electron transport chain (ETC) enzymes changed significantly. Instead, our data imply that turtles inhibit mitochondrial respiration rate and ROS production by a cumulative effect of slight inhibition of ETC complexes. Together, these results show that maintaining mitochondrial integrity while inhibiting overall enzyme activities are important aspects of anoxia tolerance. Keywords: Electron microscopy, Mitochondria, Oxygen, Reactive oxygen species, Respirometry, Supercomplex Bioblast editor: Plangger M O2k-Network Lab: DK Aarhus Fago A


Labels: MiParea: Respiration, Comparative MiP;environmental MiP 


Organism: Amphibians  Tissue;cell: Heart  Preparation: Permeabilized tissue  Enzyme: Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase 

Coupling state: LEAK, OXPHOS, ET  Pathway: N, NS  HRR: Oxygraph-2k, O2k-Fluorometer 

2020-09, AmR