Difference between revisions of "Scott 2009 Proc Biol Sci"

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Scott GR, Egginton S, Richards JG, Milsom WK (2009) Evolution of muscle phenotype for extreme high altitude flight in the bar-headed goose. Proc. Biol. Sci. 276: 3645-3653.

» PMID: 19640884

Scott GR, Egginton S, Richards JG, Milsom WK (2009) Proceedings of Biological Sciences

Abstract: Bar-headed geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the basis for this physiological feat, we compared the flight muscle phenotype of bar-headed geese with that of low altitude birds (barnacle geese, pink-footed geese, greylag geese and mallard ducks). Bar-headed goose muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the mitochondrial volume densities of each fibre type were similar between species. However, bar-headed geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations should improve O2 diffusion capacity from the blood and reduce intracellular O₂ diffusion distances, respectively. The unique differences in bar-headed geese were much greater than the minor variation between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar respiratory capacities, O2 kinetics and phosphorylation efficiencies across species. Bar-headed geese have therefore evolved for exercise in hypoxia by enhancing the O2 supply to flight muscle. • Keywords: Oxygen transport cascade, High altitude adaptation, Physiological evolution, Exercise performance, Phylogenetically independent contrasts

Labels:

Regulation: Respiration; OXPHOS; ETS Capacity"Respiration; OXPHOS; ETS Capacity" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property.

HRR: Oxygraph-2k

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 |year=2009
 |journal=Proceedings of Biological Sciences
-|abstract=Bar-headed geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain
+|abstract=Bar-headed geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the basis for this physiological feat, we compared the flight muscle phenotype of bar-headed geese with that of low altitude birds (barnacle geese, pink-footed geese, greylag geese and mallard ducks). Bar-headed goose muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the mitochondrial volume densities of each fibre type were similar between species. However, bar-headed geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations should improve O2 diffusion capacity from the blood and reduce intracellular O<sub>2</sub>   diffusion distances, respectively. The unique differences in bar-headed geese were much greater than the minor variation between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar respiratory capacities, O2 kinetics and phosphorylation efficiencies across species. Bar-headed geese have therefore evolved for exercise in hypoxia by enhancing the O2 supply to flight muscle.
-the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the
-basis for this physiological feat, we compared the flight muscle phenotype of bar-headed geese with that of
-low altitude birds (barnacle geese, pink-footed geese, greylag geese and mallard ducks). Bar-headed goose
-muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the
-mitochondrial volume densities of each fibre type were similar between species. However, bar-headed
-geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as
-well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were
-also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations
-should improve O2 diffusion capacity from the blood and reduce intracellular O2 diffusion distances,
-respectively. The unique differences in bar-headed geese were much greater than the minor variation
-between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation
-of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar
-respiratory capacities, O2 kinetics and phosphorylation efficiencies across species. Bar-headed geese
-have therefore evolved for exercise in hypoxia by enhancing the O2 supply to flight muscle.
 |keywords=Oxygen transport cascade, High altitude adaptation, Physiological evolution, Exercise performance, Phylogenetically independent contrasts
 |info=[http://www.ncbi.nlm.nih.gov/pubmed/19640884 PMID: 19640884]