Avian embryos in hypoxic environments

León‐Velarde, Fabiola; Monge-C, Carlos

doi:10.1016/j.resp.2004.02.010

Cited by 35 publications

(20 citation statements)

References 64 publications

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“…There is a shift in physiological mechanisms regulating gas exchange from conservation of water and CO 2 at middle elevation to improving O 2 diffusion above 4000 m (Carey 1994). Adult hemoglobin appears by day 6 during embryonic development (León‐Velarde and Monge 2004), and an amino acid substitution that confers a higher oxygen affinity would likely ensure higher O 2 content required for embryonic growth and development at high elevations. Individuals possessing mismatched genotypes were found in cinnamon teal (this study) and in yellow‐billed pintail ( A. georgica , McCracken et al 2009a), indicating that individuals can disperse into the highlands, perhaps because they can acclimatize to hypoxia via multiple physiological pathways.…”

Section: Discussionmentioning

confidence: 99%

Genetic and Phenotypic Divergence Between Low- And High-Altitude Populations of Two Recently Diverged Cinnamon Teal Subspecies

2012

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Section: Discussionmentioning

confidence: 99%

Genetic and Phenotypic Divergence Between Low- And High-Altitude Populations of Two Recently Diverged Cinnamon Teal Subspecies

2012

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“…Indeed, physiological processes often comprise evolvable reaction norms (Mueller, Eme, Burggren, Roghair, & Rundle, ), such as in responses to altered atmospheric oxygen (O 2 ) conditions in stressful high‐altitude environments (Rezende et al., ; Hammond et al., ; Bouverot, ; Powell, & Hopkins, ; Storz et al., ; Beall, ). In addition to low temperature, the low partial pressure of O 2 (hypoxia) at high altitudes (> 2,000 m above sea level [ASL]) renders embryonic development challenging, as fewer O 2 molecules may be available to convert egg energy into tissue (Vleck, & Vleck, ; Noble, ; Wangensteen, Rahn, Burton, & Smith, ; Rahn, Carey, Balmas, Bhatia, & Paganelli, ; Carey, Larson, Hoyt, & Bucher, ; Bouverot, ; Monge, & Leon‐Velarde, ; Leon‐Velarde, & Monge, ). Thus, altitudinal hypoxia is thought to impose a limit on the geographic distribution of vertebrate species (Powell, & Hopkins, ; Storz et al., ).…”

Section: Introductionmentioning

confidence: 99%

“…In birds, the suppression of embryonic metabolism is a common and effective means of reducing O 2 demand while undergoing egg incubation at high altitude (Monge, Leon‐Velarde, & Gomez de la Torre, ; Leon‐Velarde, & Monge, ; Lague, Chua, Farrell, Wang, & Milsom, ). This suppression is often associated with reduced heart rate and slower growth (Beattie, & Smith, ; Wangensteen et al., ; Leon‐Velarde, & Monge, ). Artificial selection and comparison of high‐ versus low‐altitude avian populations revealed that these physiological responses can evolve (Beattie, & Smith, ).…”

Section: Introductionmentioning

confidence: 99%

Physiological plasticity in lizard embryos exposed to high‐altitude hypoxia

et al. 2017

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Coping with novel environments may be facilitated by plastic physiological responses that enable survival during environmentally sensitive life stages. We tested the capacity for embryos of the common wall lizard (Podarcis muralis) from low altitude to cope with low-oxygen partial pressure (hypoxia) in an alpine environment. Developing embryos subjected to hypoxic atmospheric conditions (15-16% O sea-level equivalent) at 2,877 m above sea level exhibited responses common to vertebrates acclimatized to or evolutionarily adapted to high altitude: suppressed metabolism, cardiac hypertrophy, and hyperventilation. These responses might have contributed to the unaltered incubation duration and hatching success relative to the ancestral, low-altitude, condition. Even so, hypoxia constrained egg energy utilization such that larger eggs produced hatchlings with relatively low mass. These findings highlight the role of physiological plasticity in maintaining fitness-relevant phenotypes in high-altitude environments, providing impetus to further explore altitudinal limits to ecological diversification in ectothermic vertebrates.

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“…Thereby oxygen is not necessary to be combined with glucose to get energy. This concept resolves the mystery about normal development of avian embryos at very low tissue oxygen pressure in some species, which so was considered to involve cellular and biochemical characteristics promoting oxygen utilization [44]. Therefore, oxygen consumption by birds is practically nonexistent.…”

Section: Figure 14mentioning

confidence: 97%

Towards a New Ophthalmic Biology and Physiology: The Unsuspected Intrinsic Property of Melanin to Dissociate the Water Molecule

Herrera¹

2017

MOJCSR

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The development and evolution of eyes is ancient and difficult problem in biology. Darwin postulated a prototype eye which can evolve under natural selection. NeoDarwinists, based in morphological criteria, have postulated a polyphyletic origin that has evolved independently in the various animal phyla. Molecular phylogenetic analyses and developmental genetic experiments, cast serious doubts on both theories. The study of the development of the eye in the amphibian embryo has been a formidable tool research to experimental embryology and evolutionary biology as early as 1901. The embryonic induction, the interactions between different embryonic tissues (organizers); and the role of genes, were conceived as result of reciprocal transplantation experiments.The classical description is that the eye in vertebrates develops from the neural plate, as an evagination from the brain, forming the optic vesicle; which subsequently invaginates to form the optic cup. The inner layer of the optic cup forms the retina with its photoreceptor layers, whereas the outer layer gives rise to the pigment epithelium which absorbs the light in the back of the retina. However, failed to recognize the importance of melanin pigment. The mammalian eye consists of several layers that contain melanin, 40 % more than skin in average. Retinal, Iris and ciliary pigment epithelial cells are derived from neural ectoderm, oppositely, the uveal melanocytes, placed in choroid, iris and ciliary body stroma, are developed from the neural crest. The photo screening protective effects of melanin, the biophysical and biochemical also protective effects and biologic and photo biologic effects; have been extensively studied, but so far, researchers have been considered melanin merely as a sun block with difficult-to-explain properties. Therefore, the unsuspected intrinsic property of melanin to transforms visible and invisible light, into chemical energy, through water dissociation, as chlorophyll in plants, founded in our research facility in 2002 break the ground in regards our concepts about the biology and physiology of the body and therefore the eye. Melanin is a fundamental molecule in bioenergetic pathways, wherever is placed, and the ocular globe is not an exception. Thereby, the main function of melanin in the eye, is chemical energy production through water dissociation, as chlorophyll in plants.

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Avian embryos in hypoxic environments

Cited by 35 publications

References 64 publications

Genetic and Phenotypic Divergence Between Low- And High-Altitude Populations of Two Recently Diverged Cinnamon Teal Subspecies

Genetic and Phenotypic Divergence Between Low- And High-Altitude Populations of Two Recently Diverged Cinnamon Teal Subspecies

Physiological plasticity in lizard embryos exposed to high‐altitude hypoxia

Towards a New Ophthalmic Biology and Physiology: The Unsuspected Intrinsic Property of Melanin to Dissociate the Water Molecule

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