Hypoxic adaptations of hemoglobin in Tibetan chick embryo: High oxygen-affinity mutation and selective expression

Gou, Xin; Li, Ning; Lin-sheng, Lian; Yan, Dawei; Zhang, Hao; Wei, Z. H.; Wu, Changxin

doi:10.1016/j.cbpb.2006.11.031

Cited by 24 publications

(15 citation statements)

References 49 publications

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“…Compared to mammals, birds have notably greater tolerance of hypoxia [165][166][167] . Many species have been tracked migrating at an altitude of over 6 km 168 and the outstanding high altitude flyers include the bar-headed goose (Anser indicus) [169][170][171][172][173][174][175][176] , the Andean goose (Chloephaga melanoptera) 169,177 , the Tibetan chicken (Gallus gallus) 178 and the Ruppell's griffon vulture (Gyps rueppellii) 179 . A griffon vulture collided with a commercial jet craft at an altitude of 11.3 km (37,000 ft) over Abidjan (Cote d'Ivoire, West Africa) 180 .…”

Section: Discussionmentioning

confidence: 99%

Comparative morphometric analysis of lungs of the semifossorial giant pouched rat (Cricetomys gambianus) and the subterranean Nigerian mole rat (Cryptomys foxi)

Maina

Igbokwe

2020

Sci Rep

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Lungs of the rodent species, the African giant pouched rat (Cricetomys gambianus) and the nigerian mole rat (Cryptomys foxi) were investigated. Significant morphometric differences exist between the two species. The volume of the lung per unit body mass was 2.7 times larger; the respiratory surface area 3.4 times greater; the volume of the pulmonary capillary blood 2 times more; the harmonic mean thickness of the blood-gas (tissue) barrier (τht) ~29% thinner and; the total pulmonary morphometric diffusing capacity (DLo 2) for o 2 2.3 times more in C. foxi. C. gambianus occupies open burrows that are ventilated with air while C. foxi lives in closed burrows. the less morphometrically specialized lungs of C. gambianus may be attributed to its much larger body mass (~6 times more) and possibly lower metabolic rate and its semifossorial life whereas the 'superior' lungs of C. foxi may largely be ascribed to the subterranean hypoxic and hypercapnic environment it occupies. Compared to other rodents species that have been investigated hitherto, the τht was mostly smaller in the lungs of the subterranean species and C. foxi has the highest mass-specific DLo 2. the fossorial-and the subterranean rodents have acquired various pulmonary structural specializations that relate to habitats occupied. About 300 of the extant mammalian species that represent 54 genera and belong to 10 families of four orders live in moist and dark, climatically stable, hypoxic and hypercapnic underground burrows 1-8. Such animals inform on the natural evolutionary process of adaptation that has permitted underground life 9. In synapsids, the lineage that includes modern mammals and their ancestors 10,11 , the extinct mammal-like carnivore, the Cynodont (Thrinaxodon liorhinus) which inhabited the Karoo of South Africa ~251 million years ago (mya), is apparently the oldest known burrowing animal 12. Independently and at different amounts of time, animals invaded the underground ecotope, mostly between the upper Eocene (45-35 mya) and the Quaternary (~2 mya), when the global climate changed markedly to a colder and drier Earth 8,9,13-17. Predator avoidance, escape from extreme environmental conditions above the ground and gaining access to the subterranean parts of plants like roots, tubers, bulbs and corms and soil invertebrates were the main driving pressures for relocating to underground life. Extremophiles are life forms that have adapted to inhabiting exceptionally exacting conditions which are injurious to conventional living things 18-21. The hypoxic-and hypercapnic conditions in the unventilated, perpetually dark burrows that subterranean animals inhabit, where air may also contain noxious gases like ammonia and methane in high concentrations 22-30 , comprise extreme habitats. Of the ~250 species that occupy or take shelter in burrows, only ~25 species, most of which are mole rats of the Family Talpidae, permanently live underground 31-36. Because they are concealed and most of them pose a challenge of keeping and breeding them in the labor...

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Section: Discussionmentioning

confidence: 99%

Comparative morphometric analysis of lungs of the semifossorial giant pouched rat (Cricetomys gambianus) and the subterranean Nigerian mole rat (Cryptomys foxi)

Maina

Igbokwe

2020

Sci Rep

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“…The most pervasive mechanism for sustaining the circulation of O 2 in hypoxia is an alteration in the O 2 -binding properties of haemoglobin in the blood. Numerous highaltitude birds, such as the bar-headed goose (Fig.5), Andean goose (Chloephaga melanoptera) (Black and Tenney, 1980), Tibetan chicken (Gallus gallus) (Gou et al, 2007) and Ruppell's griffon (Gyps rueppellii) (Weber et al, 1988), are known to possess haemoglobins with an increased O 2 affinity. This can dramatically increase O 2 delivery and pulmonary O 2 loading in hypoxia by increasing the saturation of haemoglobin (and thus the O 2 content of the blood) at a given O 2 partial pressure (Fig.5A), and can, in doing so, greatly improve flux through the O 2 transport pathway (Scott and Milsom, 2006).…”

Section: The Unique Attributes Of High Fliersmentioning

confidence: 99%

Elevated performance: the unique physiology of birds that fly at high altitudes

Scott

2011

Journal of Experimental Biology

138

113

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Summary Birds that fly at high altitudes must support vigorous exercise in oxygen-thin environments. Here I discuss the characteristics that help high fliers sustain the high rates of metabolism needed for flight at elevation. Many traits in the O2 transport pathway distinguish birds in general from other vertebrates. These include enhanced gas-exchange efficiency in the lungs, maintenance of O2 delivery and oxygenation in the brain during hypoxia, augmented O2 diffusion capacity in peripheral tissues and a high aerobic capacity. These traits are not high-altitude adaptations, because they are also characteristic of lowland birds, but are nonetheless important for hypoxia tolerance and exercise capacity. However, unique specializations also appear to have arisen, presumably by high-altitude adaptation, at every step in the O2 pathway of highland species. The distinctive features of high fliers include an enhanced hypoxic ventilatory response, an effective breathing pattern, larger lungs, haemoglobin with a higher O2 affinity, further augmentation of O2 diffusion capacity in the periphery and multiple alterations in the metabolic properties of cardiac and skeletal muscle. These unique specializations improve the uptake, circulation and efficient utilization of O2 during high-altitude hypoxia. High-altitude birds also have larger wings than their lowland relatives to reduce the metabolic costs of staying aloft in low-density air. High fliers are therefore unique in many ways, but the relative roles of adaptation and plasticity (acclimatization) in high-altitude flight are still unclear. Disentangling these roles will be instrumental if we are to understand the physiological basis of altitudinal range limits and how they might shift in response to climate change.

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“…For example, in the bar-headed goose ( Anser indicus ) [11, 12, 19], the Andean goose ( Chloephaga melanoptera ) [22, 23], the Tibetan chicken ( Gallus gallus ) [24] and the Ruppell’s griffon vulture ( Gyps rueppellii ) [25], mutations of hemoglobin have generated molecular configurations that increase O 2 affinity [23–28]. Bar-headed geese in particular have evolved increased capacity of transporting O 2 along the path from the atmosphere to the mitochondria [19].…”

Section: Introductionmentioning

confidence: 99%

Morphological and morphometric specializations of the lung of the Andean goose, Chloephaga melanoptera: A lifelong high-altitude resident

et al. 2017

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High altitude flight in rarefied, extremely cold and hypoxic air is a very challenging activity. Only a few species of birds can achieve it. Hitherto, the structure of the lungs of such birds has not been studied. This is because of the rarity of such species and the challenges of preparing well-fixed lung tissue. Here, it was posited that in addition to the now proven physiological adaptations, high altitude flying birds will also have acquired pulmonary structural adaptations that enable them to obtain the large amounts of oxygen (O2) needed for flight at high elevation, an environment where O2 levels are very low. The Andean goose (Chloephaga melanoptera) normally resides at altitudes above 3000 meters and flies to elevations as high as 6000 meters where O2 becomes limiting. In this study, its lung was morphologically- and morphometrically investigated. It was found that structurally the lungs are exceptionally specialized for gas exchange. Atypically, the infundibulae are well-vascularized. The mass-specific volume of the lung (42.8 cm3.kg-1), the mass-specific respiratory surface area of the blood-gas (tissue) barrier (96.5 cm2.g-1) and the mass-specific volume of the pulmonary capillary blood (7.44 cm3.kg-1) were some of the highest values so far reported in birds. The pulmonary structural specializations have generated a mass-specific total (overall) pulmonary morphometric diffusing capacity of the lung for oxygen (DLo2) of 0.119 mlO2.sec-1.mbar-1.kg-1, a value that is among some of the highest ones in birds that have been studied. The adaptations of the lung of the Andean goose possibly produce the high O2 conductance needed to live and fly at high altitude.

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Hypoxic adaptations of hemoglobin in Tibetan chick embryo: High oxygen-affinity mutation and selective expression

Cited by 24 publications

References 49 publications

Comparative morphometric analysis of lungs of the semifossorial giant pouched rat (Cricetomys gambianus) and the subterranean Nigerian mole rat (Cryptomys foxi)

Comparative morphometric analysis of lungs of the semifossorial giant pouched rat (Cricetomys gambianus) and the subterranean Nigerian mole rat (Cryptomys foxi)

Elevated performance: the unique physiology of birds that fly at high altitudes

Morphological and morphometric specializations of the lung of the Andean goose, Chloephaga melanoptera: A lifelong high-altitude resident

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