Coulson 2024 J Exp Biol
| Coulson SZ, Guglielmo CG, Staples JF (2024) Migration increases mitochondrial oxidative capacity without increasing reactive oxygen species emission in a songbird. J Exp Biol 227:jeb246849. https://doi.org/10.1242/jeb.246849 |
Coulson Soren Z, Guglielmo Christopher G, Staples James F (2024) J Exp Biol
Abstract: Birds remodel their flight muscle metabolism prior to migration to meet the physiological demands of migratory flight, including increases in both oxidative capacity and defence against reactive oxygen species. The degree of plasticity mediated by changes in these mitochondrial properties is poorly understood but may be explained by two non-mutually exclusive hypotheses: variation in mitochondrial quantity or in individual mitochondrial function. We tested these hypotheses using yellow-rumped warblers (Setophaga coronata), a Nearctic songbird which biannually migrates 2000-5000 km. We predicted higher flight muscle mitochondrial abundance and substrate oxidative capacity, and decreased reactive oxygen species emission in migratory warblers captured during autumn migration compared with a short-day photoperiod-induced non-migratory phenotype. We assessed mitochondrial abundance via citrate synthase activity and assessed isolated mitochondrial function using high-resolution fluororespirometry. We found 60% higher tissue citrate synthase activity in the migratory phenotype, indicating higher mitochondrial abundance. We also found 70% higher State 3 respiration (expressed per unit citrate synthase) in mitochondria from migratory warblers when oxidizing palmitoylcarnitine, but similar H2O2 emission rates between phenotypes. By contrast, non-phosphorylating respiration was higher and H2O2 emission rates were lower in the migratory phenotype. However, flux through electron transport system complexes I-IV, II-IV and IV was similar between phenotypes. In support of our hypotheses, these data suggest that flight muscle mitochondrial abundance and function are seasonally remodelled in migratory songbirds to increase tissue oxidative capacity without increasing reactive oxygen species formation. • Keywords: Endurance locomotion, Energetics, Flight muscle, Locomotory performance, OXPHOS, Plasticity, ROS • Bioblast editor: Plangger M • O2k-Network Lab: CA London Staples JF
Labels: MiParea: Respiration, Comparative MiP;environmental MiP
Organism: Birds
Tissue;cell: Skeletal muscle
Preparation: Isolated mitochondria
Coupling state: LEAK, OXPHOS
Pathway: F, N, S, CIV
HRR: Oxygraph-2k, O2k-Fluorometer
2024-07, AmR
