Hypoxia acclimation improves mitochondrial efficiency in the aerobic swimming muscle of red drum (Sciaenops ocellatus)

Copyright © 2023 Elsevier Inc. All rights reserved..

Environmental hypoxia (low dissolved oxygen) is a significant threat facing fishes. As fishes require oxygen to efficiently produce ATP, hypoxia can significantly limit aerobic capacity. However, some fishes show respiratory flexibility that rescues aerobic performance, including plasticity in mitochondrial performance. This plasticity may result in increased mitochondrial efficiency (e.g., less proton leak), increased oxygen storage capacity (increased myoglobin), and oxidative capacity (e.g., higher citrate synthase activity) under hypoxia. We acclimated a hypoxia-tolerant fish, red drum (Sciaenops ocellatus), to 8-days of constant hypoxia to induce a hypoxic phenotype. Fish were terminally sampled for cardiac and red muscle tissue to quantify oxidative phosphorylation, proton leak, and maximum respiration in tissue from both hypoxia-acclimated and control fish. Tissue was also collected to assess the plasticity of citrate synthase enzyme activity and mRNA expression for select oxygen storage and antioxidant pathway transcripts. We found that mitochondrial respiration rates were not affected by hypoxia exposure in cardiac tissue, though citrate synthase activity and myoglobin expression were higher following hypoxia acclimation. Interestingly, measures of mitochondrial efficiency in red muscle significantly improved in hypoxia-acclimated individuals. Hypoxia-acclimated fish had significantly higher OXPHOS Control Efficiency, OXPHOS Capacity and Coupling Control Ratios (i.e., LEAK/OXPHOS). There was no significant change to citrate synthase activity or myoglobin expression in red muscle. Overall, these results suggest that red muscle mitochondria of hypoxia-acclimated fish more efficiently utilize oxygen, which may explain previous reports in red drum of improved aerobic swimming performance in the absence of improved maximum metabolic rate following hypoxia acclimation.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:282

Enthalten in:

Comparative biochemistry and physiology. Part A, Molecular & integrative physiology - 282(2023) vom: 15. Aug., Seite 111443

Sprache:

Englisch

Beteiligte Personen:

Ackerly, Kerri Lynn [VerfasserIn]
Negrete, Benjamin [VerfasserIn]
Dichiera, Angelina M [VerfasserIn]
Esbaugh, Andrew J [VerfasserIn]

Links:

Volltext

Themen:

Citrate (si)-Synthase
EC 2.3.3.1
Fish
Heart
Journal Article
Low oxygen
Myoglobin
Oxidative phosphorylation
Oxygen
Protons
Red muscle
Research Support, Non-U.S. Gov't
S88TT14065

Anmerkungen:

Date Completed 14.06.2023

Date Revised 25.06.2023

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.cbpa.2023.111443

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM357041917