Low oxygen levels can help to prevent the detrimental effect of acute warming on mitochondrial efficiency in fish

Type Article
Date 2021-02
Language English
Author(s) Thoral ElisaORCID1, Roussel Damien1, Chinopoulos ChristosORCID2, Teulier LoïcORCID1, Salin KarineORCID3
Affiliation(s) 1 : Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
2 : Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary
3 : Université de Brest, Ifremer, CNRS, IRD, Laboratory of Environmental Marine Sciences, Plouzané 29280, France
Source Biology Letters (1744-957X) (The Royal Society), 2021-02 , Vol. 17 , N. 2 , P. 20200759 (5p.)
DOI 10.1098/rsbl.2020.0759
Keyword(s) ATP/O ratio, mitochondrial respiratory capacities, dissolved oxygen, temperature

Aerobic metabolism of aquatic ectotherms is highly sensitive to fluctuating climates. Many mitochondrial traits exhibit phenotypic plasticity in response to acute variations in temperature and oxygen availability. These responses are critical for understanding the effects of environmental variations on aquatic ectotherms' performance. Using the European seabass, Dicentrarchus labrax, we determined the effects of acute warming and deoxygenation in vitro on mitochondrial respiratory capacities and mitochondrial efficiency to produce ATP (ATP/O ratio). We show that acute warming reduced ATP/O ratio but deoxygenation marginally raised ATP/O ratio, leading to a compensatory effect of low oxygen availability on mitochondrial ATP/O ratio at high temperature. The acute effect of warming and deoxygenation on mitochondrial efficiency might be related to the leak of protons across the mitochondrial inner membrane, as the mitochondrial respiration required to counteract the proton leak increased with warming and decreased with deoxygenation. Our study underlines the importance of integrating the combined effects of temperature and oxygen availability on mitochondrial metabolism. Predictions on decline in performance of aquatic ectotherms owing to climate change may not be accurate, since these predictions typically look at respiratory capacity and ignore efficiency of ATP production.

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