Mitochondrial physiology in the skeletal and cardiac muscles is altered in torrent ducks, Merganetta armata, from high altitudes in the Andes.
Torrent ducks inhabit fast-flowing rivers in the Andes from sea level to altitudes up to 4500 m. We examined the mitochondrial physiology that facilitates performance over this altitudinal cline by comparing the respiratory capacities of permeabilized fibers, the activities of 16 key metabolic enzymes and the myoglobin content in muscles between high- and low-altitude populations of this species. Mitochondrial respiratory capacities (assessed using substrates of mitochondrial complexes I, II and/or IV) were higher in highland ducks in the gastrocnemius muscle - the primary muscle used to support swimming and diving - but were similar between populations in the pectoralis muscle and the left ventricle. The heightened respiratory capacity in the gastrocnemius of highland ducks was associated with elevated activities of cytochrome oxidase, phosphofructokinase, pyruvate kinase and malate dehydrogenase (MDH). Although respiratory capacities were similar between populations in the other muscles, highland ducks had elevated activities of ATP synthase, lactate dehydrogenase, MDH, hydroxyacyl CoA dehydrogenase and creatine kinase in the left ventricle, and elevated MDH activity and myoglobin content in the pectoralis. Thus, although there was a significant increase in the oxidative capacity of the gastrocnemius in highland ducks, which correlates with improved performance at high altitudes, the variation in metabolic enzyme activities in other muscles not correlated to respiratory capacity, such as the consistent upregulation of MDH activity, may serve other functions that contribute to success at high altitudes.
Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada neal.dawson@gmail.com.|Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, FL 33146, USA.
Neal J
0000-0001-5389-8692
NJ
Dawson
Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada.
Catherine M
CM
Ivy
Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, FL 33146, USA.|Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.|Centro de Ornitología y Biodiversidad - CORBIDI, Lima 33, Peru.
Luis
L
Alza
Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
Rebecca
R
Cheek
Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada.
Julia M
JM
York
Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada.
Beverly
B
Chua
Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada.
William K
WK
Milsom
Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, FL 33146, USA.|Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
Kevin G
KG
McCracken
Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada.
Graham R
GR
Scott
D000101:Acetyl-CoA C-Acetyltransferase / Q000378:metabolism; D000531:Altitude; D025041:Animal Migration / Q000502:physiology; D000818:Animals; D003402:Creatine Kinase / Q000378:metabolism; D004372:Ducks / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D006352:Heart Ventricles / Q000378:metabolism; D045022:Lactate Dehydrogenases / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism* / Q000502:physiology; D018482:Muscle, Skeletal / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D009211:Myoglobin / Q000378:metabolism; D010369:Pectoralis Muscles / Q000378:metabolism*; D025221:Phosphofructokinases / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D013020:South America
D009211:Myoglobin; D045022:Lactate Dehydrogenases; D008291:Malate Dehydrogenase; D003576:Electron Transport Complex IV; D000101:Acetyl-CoA C-Acetyltransferase; D025221:Phosphofructokinases; D011770:Pyruvate Kinase; D003402:Creatine Kinase
Energy metabolism; High altitude; Mitochondrial respiration; Muscle energetics; Myoglobin