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Coyotes-Wolves-Cougars.blogspot.com

Grizzly bears, black bears, wolves, coyotes, cougars/ mountain lions,bobcats, wolverines, lynx, foxes, fishers and martens are the suite of carnivores that originally inhabited North America after the Pleistocene extinctions. This site invites research, commentary, point/counterpoint on that suite of native animals (predator and prey) that inhabited The Americas circa 1500-at the initial point of European exploration and subsequent colonization. Landscape ecology, journal accounts of explorers and frontiersmen, genetic evaluations of museum animals, peer reviewed 20th and 21st century research on various aspects of our "Wild America" as well as subjective commentary from expert and layman alike. All of the above being revealed and discussed with the underlying goal of one day seeing our Continent rewilded.....Where big enough swaths of open space exist with connective corridors to other large forest, meadow, mountain, valley, prairie, desert and chaparral wildlands.....Thereby enabling all of our historic fauna, including man, to live in a sustainable and healthy environment. - Blogger Rick

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Tuesday, February 11, 2014

How do polar bears stay warm? Unlike Grizzlies and Black Bears that hibernate, only pregnant female Polar Bears "snooze" during the winter months..........All males and non pregnant females brave the elements of their very cold world................In a new study, a team led by the University at Buffalo reports that genes controlling nitric oxide production in the polar bear genome contain genetic differences from comparable genes in brown(Grizzlies) and black bears.................Typically, cells transform nutrients into energy............. However, there is a phenomenon called adaptive or non-shivering thermogenesis where the cells will produce heat instead of energy in response to a particular diet or environmental conditions.................The Polar Bears "adaptive thermogenesis" is what ups their internal thermostat to keep them warm and alive during the Polar winter

How do polar bears stay warm? Research finds an answer in their genes

How do polar bears stay warm? Research finds an answer in their genes

polar bear looking straight at camera
A male polar bear. Credit: U.S. Geological Survey, Steven C. Amstrup

New study is part of a broader genomic research program aimed at understanding what makes a polar bear a polar bear

Release Date: February 10, 2014
“Gene functions that had to do with nitric oxide production seemed to be more enriched in the polar bear than in the brown bears and in the black bears.”
Charlotte Lindqvist, assistant professor of biological sciences
University at Buffalo
Download High-Res Images:
A polar bear looking straight at the camera
A male polar bear. Credit: U.S. Geological Survey, Steven C. Amstrup
polar bear walking on an icy terrain
A male polar bear walks on pack ice. Credit: U.S. Fish and Wildlife Service, Eric Regehr
polar bear walking by water
A polar bear in Alaska. Credit: U.S. Fish and Wildlife Service, Steve Hillebrand
a polar bear lying down and facing camera
A polar bear at rest. Credit: U.S. Fish and Wildlife Service, Susanne Miller
Charlotte Lindqvist in front of a background showing a polar bear walking in a cold climate
UB researcher Charlotte Lindqvist led the study, which is part of a larger research program devoted to understanding how the polar bear has adapted to the harsh Arctic environment. Credit: University at Buffalo, Douglas Levere
BUFFALO, N.Y. — In the winter, brown and black bears go into hibernation to conserve energy and keep warm.
But things are different for their Arctic relative, the polar bear. Within this high-latitude species, only pregnant females den up for the colder months.
So how do the rest survive the extreme Arctic winters?
New research points to one potential answer: genetic adaptations related to the production of nitric oxide, a compound that cells use to help convert nutrients from food into energy or heat.
In a new study, a team led by the University at Buffalo reports that genes controlling nitric oxide production in the polar bear genome contain genetic differences from comparable genes in brown and black bears.
“With all the changes in the global climate, it becomes more relevant to look into what sorts of adaptations exist in organisms that live in these high-latitude environments,” said lead researcher Charlotte Lindqvist, PhD, UB assistant professor of biological sciences.
“This study provides one little window into some of these adaptations,” she said. “Gene functions that had to do with nitric oxide production seemed to be more enriched in the polar bear than in the brown bears and black bears. There were more unique variants in polar bear genes than in those of the other species.”
The paper, titled “Polar Bears Exhibit Genome-Wide Signatures of Bioenergetic Adaptation to Life in the Arctic Environment,” appeared Feb. 6 in the journal Genome Biology and Evolution.
Co-authors include scientists from UB, Penn State University, the U.S. Geological Survey Alaska Science Center, Durham University and the University of California, Santa Cruz.
The genetic adaptations the research team saw are important because of the crucial role that nitric oxide plays in energy metabolism.
Typically, cells transform nutrients into energy. However, there is a phenomenon called adaptive or non-shivering thermogenesis, where the cells will produce heat instead of energy in response to a particular diet or environmental conditions.
Levels of nitric oxide production may be a key switch triggering how much heat or energy is produced as cells metabolize nutrients, or how much of the nutrients is stored as fat, Lindqvist said.
“At high levels, nitric oxide may inhibit energy production,” said Durham University’s Andreanna Welch, PhD, first author and a former postdoctoral researcher at UB with Lindqvist. “At more moderate levels, however, it may be more of a tinkering, where nitric oxide is involved in determining whether — and when — energy or heat is produced.”
The research is part of a larger research program devoted to understanding how the polar bear has adapted to the harsh Arctic environment, Lindqvist said.
In 2012, she and colleagues reported sequencing the genomes of multiple brown bears, black bears and polar bears.
In a paper in the Proceedings of the National Academy of Sciences, the team said comparative studies between the DNA of the three species uncovered some distinctive polar bear traits, such as genetic differences that may affect the function of proteins involved in the metabolism of fat — a process that’s very important for insulation.
In the new study, the scientists looked at the mitochondrial and nuclear genomes of 23 polar bears, three brown bears and a black bear.
The research was funded by the University at Buffalo and the National Fish and Wildlife Foundation.

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