| adaptation of bird hemoglobins to high altitudes: demonstration of molecular mechanism by protein engineering. | of two closely related species of geese, one, the greylag goose, lives in the indian plains all year round, while the other, the bar-headed goose, lives at the tibetan lakes and migrates across the himalayas to winter in india. another species, the andean goose, lives in the high andes all year round. possession of a hb with high oxygen affinity helps to adapt bar-headed and andean geese to high altitudes. the hb amino acid sequences of the bar-headed and the greylag geese differ by four substit ... | 1991 | 1862080 |
| the primary structures of the major and minor hemoglobin-components of adult andean goose (chloephaga melanoptera, anatidae): the mutation leu----ser in position 55 of the beta-chains. | the primary structures of the hemoglobin components hb a and hb d of the adult andean goose (chloephaga melanoptera) are presented. the globin chains were separated on cm-cellulose in 8m urea buffer. the amino-acid sequences were established by automatic edman degradation of the globin chains and of the tryptic peptides in liquid- and gas-phase sequenators. the sequences are aligned with those of greylag goose (anser anser) as a biological reference and other sequences of birds. a detailed evalu ... | 1987 | 3442599 |
| mutant hemoglobins (alpha 119-ala and beta 55-ser): functions related to high-altitude respiration in geese. | the unusually high blood-o2 affinity in the bar-headed and andean geese is a necessary adaptation for migration across high mountain ranges. the amino acid residues alpha-119 and beta-55, which form an alpha 1 beta 1 contact in human hemoglobin (hb), are altered in bar-headed and andean geese, respectively, which suggests that loss of this contact increases o2 affinity. two mutant human hbs with equivalent mutations at these sites prepared by site-directed mutagenesis show the same increase in o ... | 1993 | 8125885 |
| phylogenetic and structural analysis of the hba (alphaa/betaa) and hbd (alphad/betaa) hemoglobin genes in two high-altitude waterfowl from the himalayas and the andes: bar-headed goose (anser indicus) and andean goose (chloephaga melanoptera). | two species of waterfowl living at high altitude provide a prominent example of parallel adaptation at the molecular level. the bar-headed goose (anser indicus) breeds at high elevations in central asia and migrates across the himalayas, where the partial pressure of oxygen (o(2)) is one-third of sea level. in south america, the distantly related andean goose (chloephaga melanoptera) is endemic to the high andes. both species exhibit increased blood-o(2) affinity, which has been attributed to th ... | 2010 | 20434566 |
| [molecular aspects of high altitude respiration of birds. hemoglobins of the striped goose (anser indicus), the andean goose, (chloephaga melanoptera) and vulture (gyps rueppellii)]. | respiration of birds at high altitude and the structural adaptation of avian hemoglobins are studied. applying the method of the "minimal biological distance", hemoglobins of closely related species were sequenced and compared with each other. physiological measurements and sequence data show that adaptation to hypoxic stress can be interpreted as exchange of one amino acid. the structural aspects of the genetical data are discussed on the basis of the atomic model of hemoglobin. high-altitude r ... | 1988 | 3205309 |
| morphological and morphometric specializations of the lung of the andean goose, chloephaga melanoptera: a lifelong high-altitude resident. | 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 ... | 2017 | 28339478 |
| high-altitude champions: birds that live and migrate at altitude. | high altitude is physiologically challenging for vertebrate life for many reasons, including hypoxia (low environmental oxygen); yet, many birds thrive at altitude. compared to mammals, birds have additional enhancements to their oxygen transport cascade, the conceptual series of steps responsible for acquiring oxygen from the environment and transporting it to the mitochondria. these adaptations have allowed them to inhabit a number of high-altitude regions. waterfowl are a taxon prolific at al ... | 2017 | 28839002 |
| cardiovascular responses to progressive hypoxia in ducks native to high altitude in the andes. | the cardiovascular system is critical for delivering o2 to tissues. here, we examined the cardiovascular responses to progressive hypoxia in four high-altitude andean duck species compared with four related low-altitude populations in north america, tested at their native altitude. ducks were exposed to stepwise decreases in inspired partial pressure of o2 while we monitored heart rate, o2 consumption rate, blood o2 saturation, haematocrit (hct) and blood haemoglobin (hb) concentration. we calcu ... | 2020 | 32041807 |
| crystal structure analysis of great cormorant (phalacrocorax carbo) hemoglobin to understand its high oxygen affinity characteristics by special structural features. | hemoglobin (hb) subunits are composed of the specific functional prosthetic group "heme'' and a protein moiety "globin". bird hbs are functionally similar to mammalian hbs but they are structurally dissimilar with mammalian. the insufficient structural studies on avian hbs limit us to understand their degree of adaptation to such critical environments. the great cormorant (gct) can fly and swim, the dual characteristic of gct leads to study the sturcture of hemoglobin. | 2018 | 29929459 |
| respiratory mechanics and morphology of tibetan and andean high-altitude geese with divergent life histories. | high-altitude bar-headed geese (anser indicus) and andean geese (chloephaga melanoptera) have been shown to preferentially increase tidal volume over breathing frequency when increasing ventilation during exposure to hypoxia. increasing tidal volume is a more effective breathing strategy but is also thought to be more mechanically and metabolically expensive. we asked whether there might be differences in the mechanics or morphology of the respiratory systems of high-altitude transient bar-heade ... | 2018 | 29180602 |
| divergent respiratory and cardiovascular responses to hypoxia in bar-headed geese and andean birds. | many high-altitude vertebrates have evolved increased capacities in their oxygen transport cascade (ventilation, pulmonary diffusion, circulation and tissue diffusion), enhancing oxygen transfer from the atmosphere to mitochondria. however, the extent of interspecies variation in the control processes that dictate hypoxia responses remains largely unknown. we compared the metabolic, cardiovascular and respiratory responses to progressive decreases in inspired oxygen levels of bar-headed geese (a ... | 2017 | 29141880 |
| validation of a pulse oximetry system for high-altitude waterfowl by examining the hypoxia responses of the andean goose (chloephaga melanoptera). | hypoxia at high altitudes constrains o2 supply to support metabolism, thermoregulation in the cold, and exercise. high-altitude natives that somehow overcome this challenge-who live, reproduce, and sometimes perform impressive feats of exercise at high altitudes-are a powerful group in which to study the evolution of physiological systems underlying hypoxia resistance. here, we sought to determine whether a common pulse oximetry system for rodents (mouseox plus) can be used reliably in studies o ... | 2018 | 29513620 |