How hummingbirds evolved to fly at high altitude
(Phys.org) —High up in the Andes, numerous species of hummingbirds are thriving despite low levels of oxygen.
(Phys.org) —High up in the Andes, numerous species of hummingbirds are thriving despite low levels of oxygen.
Evolution
Dec 03, 2013
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1
For millennia, the massive Tibetan mastiff has laid literal claim to the label "top dog."
Plants & Animals
Sep 04, 2019
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368
University of Houston associate professor of chemistry, Vassiliy Lubchenko, is reporting a new finding in Nature Communications on how sickle cells are formed. Lubchenko reports that droplets of liquid, enriched in hemoglobin, ...
Biochemistry
Jul 02, 2019
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0
On the Himalayan-enveloped Tibetan Plateau and the Altiplano plateau of South America – the world's two highest tabletops – a select few bird species survive on 35 to 40 percent less oxygen than at sea level.
Biochemistry
Feb 19, 2018
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121
About one quarter of the world's population suffers from anemia, a disease caused by a concentration deficiency of hemoglobin in red blood cells. To reduce the burden of anemia, health officials need a better picture of the ...
General Physics
Oct 03, 2017
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8
Computer models developed by Brown University mathematicians show new details of what happens inside a red blood cell affected by sickle cell disease. The researchers said they hope their models, described in an article in ...
Biochemistry
Jul 28, 2017
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237
There's at least one person in the world for whom smoking has a beneficial effect, and it took an international collaboration of scientists led by a Rice University professor to figure out why.
Biochemistry
Feb 16, 2017
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323
New research from North Carolina State University shows that iron may play a role in preserving ancient tissues within dinosaur fossils, but also may hide them from detection. The finding could open the door to the recovery ...
Archaeology
Nov 26, 2013
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0
(Phys.org) —A UConn research team has found a way to stabilize hemoglobin, the oxygen carrier protein in the blood, a discovery that could lead to the development of stable vaccines and affordable artificial blood substitutes.
Materials Science
Nov 19, 2013
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0
With mutations, it turns out that context can be everything in determining whether or not they are beneficial to their evolutionary fate.
Evolution
Jun 13, 2013
1
0
Hemoglobin (English pronunciation: /hiːməˈɡloʊbɪn/; also rendered as haemoglobin and abbreviated Hb or Hgb) is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates. Hemoglobin in the blood carries oxygen from the respiratory organs (lungs or gills) to the rest of the body (i.e., the tissues) where it releases the oxygen to burn nutrients to provide energy to power the functions of the organism, and collects the resultant carbon dioxide to bring it back to the respiratory organs to be dispensed from the organism.
In mammals, the protein makes up about 97% of the red blood cells' dry content, and around 35% of the total content (including water).[citation needed] Hemoglobin has an oxygen binding capacity of 1.34 ml O2 per gram of hemoglobin, which increases the total blood oxygen capacity seventy-fold compared to dissolved oxygen in blood. The mammalian hemoglobin molecule can bind (carry) up to four oxygen molecules.
Hemoglobin is involved in the transport of other gases: it carries some of the body's respiratory carbon dioxide (about 10% of the total) as carbaminohemoglobin, in which CO2 is bound to the globin protein. The molecule also carries the important regulatory molecule nitric oxide bound to a globin protein thiol group, releasing it at the same time as oxygen.
Hemoglobin is also found outside red blood cells and their progenitor lines. Other cells that contain hemoglobin include the A9 dopaminergic neurons in the substantia nigra, macrophages, alveolar cells, and mesangial cells in the kidney. In these tissues, hemoglobin has a non-oxygen-carrying function as an antioxidant and a regulator of iron metabolism.
Hemoglobin and hemoglobin-like molecules are also found in many invertebrates, fungi, and plants. In these organisms, hemoglobins may carry oxygen, or they may act to transport and regulate other things such as carbon dioxide, nitric oxide, hydrogen sulfide and sulfide. A variant of the molecule, called leghemoglobin, is used to scavenge oxygen, to keep it from poisoning anaerobic systems, such as nitrogen-fixing nodules of leguminous plants.
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