hibernate

In the meantime, I think I'll hibernate

dr. dolittle — Wed, 02 Nov 2016 00:24:12 +0000

In the meantime, I think I'll hibernate

By Shanghai killer whale (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

I just read an interesting blog from the I Spy Physiology website sponsored by the American Physiological Society which described results from a recent study suggesting that chronic fatigue syndrome (CFS) might be a human equivalent to hibernation.

Chronic fatigue syndrome reportedly affects over 2.5 million people in the United States alone. People with this condition have the type of fatigue that does not seem to improve, even with adequate sleep.

By examining the blood of people with and without CFS, researchers have now discovered that those with the condition have less metabolites. What this means is that metabolism is reduced in people with CFS, much like a hibernating animal. Hibernation is typically a state animals enter to conserve energy in order to deal with environmental challenges (like winter) or stressors. For humans, this hibernation-like state may be a way to cope with stress as well since it often begins following an illness or major stress event. Hopefully this new research will help identify potential therapeutic targets to turn off this seemingly protective mechanism in those who suffer from CFS.

Sources:

http://www.pnas.org/content/113/37/E5472.full

I Spy Physiology blog

dr. dolittle Tue, 11/01/2016 - 20:24

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Life Science

chronic fatigue

hibernate

hibernation

sleep

stress

Beware of freezing hearts

dr. dolittle — Fri, 22 Jan 2016 15:44:15 +0000

Beware of freezing hearts

Image of a hibernating thirteen-lined ground squirrel from University of Minnesota Duluth researcher Matthew Andrews.

Thirteen-lined ground squirrels (Ictidomys tridecemlineatus) are really cute when they hibernate (above). During torpor bouts, their body temperature decreases to a few degrees Celsius and their metabolism drops by as much as 95% with heart rates ranging from only 3-10 beats per minute. These bouts of torpor are interrupted by periodic arousals every couple of weeks during which their metabolism increases as body temperature elevates to 37 degrees Celsius. What is so fascinating is that they are able to decrease their body temperature below what would cause other animals to undergo cardiac arrest. Dr. Matthew Andrews at the University of Minnesota, Duluth wanted to know how these squirrels protected their hearts from a similar fate during bouts of torpor. His team characterized changes in heart proteins from animals during warm months (controls), animals in torpor as well as those aroused from torpor. They discovered that dozens of proteins show differences in their expression patterns at each of these stages in addition to novel forms of proteins found in ground squirrels. Their findings are published in the Journal of Proteome Research.

Sources:

Vermillion KL, Jagtap P, Johnson JE, Griffin TJ, Andrews MT. Characterizing Cardiac Molecular Mechanisms of Mammalian Hibernation via Quantitative Proteogenomics. Journal of Proteome Research. 14:4792-804, 2015.

The Scientist

dr. dolittle Fri, 01/22/2016 - 10:44

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Is anything known about what's happening in their brains during deep hibernation? I would expect that their EEG in hibernation would be substantially different to what occurs during regular sleep.

While we're at it, a behavioral experiment might be of interest, to ascertain whether the squirrels' brains are capable of integrating sensory information while sleeping and hibernating:

During deep hibernation as measured by heart rate, present them with a sequence of two audio tones. Follow the tones with the smell of food.

Do likewise with waking squirrels and sleeping squirrels.

The duration of the tones played, should be extended proportionally to decrease in heart rate in the sleeping and hibernating states as compared to the waking state. This on the basis that acquisition of sensory data is slowed somewhat as brain activity also slows down.

After some number of repetitions that should be sufficient for a learned association to occur, present the same tones to all of the squirrels when they are awake, and observe if the squirrels exhibit food-oriented behavior after hearing the tones, as compared to control groups in each category who did not hear the tones followed by the smell of food.

Polar bear survival during summer

dr. dolittle — Tue, 21 Jul 2015 00:41:04 +0000

Polar bear survival during summer

If you happen to be in the Arctic this summer polar bears (Ursus maritimus) can be spotted spending their time on the sea ice or on the shore in areas where ice has melted. While it is difficult to study the physiology of bears living on the ice, it had been hypothesized that bears living on shore experience a state similar to winter hibernation in which they attempt to decrease their energy expenditure when food resources are low. However, new research published in Science shows that bears living on the ice as well as those on shore experience some decrease in activity as well as body temperature while their energy expenditure is actually similar to that of animals that are fasting but not hibernating.

The research team enlisted help from the US Geological Survey, US Fish and Wildlife Service, two helicopters and an ice-breaking vessel to help capture and tag over two dozen polar bears as well as implant 17 bears with a probe that can measure body temperature. It took 36 days just to recapture the animals with the temperature probes!

With the Arctic ice beginning to melt earlier in the summer and also taking longer to freeze in the winter, these prolonged periods of ice melt may be a challenge to the animal's survival over time according to study co-author Merav Ben-David (University of Wyoming - Laramie).

Sources:

Whiteman JP, Harlow HJ, Durner GM, Anderson-Sprecher R, Albeke SE, Regehr EV, Amstrup SC, Ben-David M. Summer declines in activity and body temperature offer polar bears limited energy savings. Science, 349(6245), 295-298, July 2015.
DOI: 10.1126/science.aaa8623

Image of a "shore" polar bear from National Geographic.

dr. dolittle Mon, 07/20/2015 - 20:41

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Amazing what a "cool" summer can do:
http://www.bbc.com/news/science-environment-33594654

Thank you for sharing this article. The polar bears in this research were studied in 2008 and 2009.

The summer will be amazing.

Bunker Bats

dr. dolittle — Thu, 09 May 2013 16:15:21 +0000

Bunker Bats

A Cold War bunker at Loring Air Force Base in Maine that has been converted into a winter haven for bats. Image from: BBC News, USFWS/S. Agius

Scientists in Maine have converted two Cold War bunkers at Loring Air Force Base into winter havens for bats in an effort to protect the animals from the fungus that causes white nose syndrome. What is nice about using a man-made space is that they can actually clean up the area as opposed to trying to kill the fungus in a cave where multiple species of fungi may be affected, thereby disrupting the micro-ecosystem. The winter survival rate is not very high so far, only 9 out of 30 of the animals survived the stress of capture, transport, and captivity. The researchers have added roosts and closed captioning televisions to the bunkers to help study the animals. I hope their efforts at creating man-made safe havens for these bats works as this fungus has killed up to 6.7 million bats to date, and is continuing to spread.

For more information on these bunkers, visit BBC News.

For prior posts on white nose syndrome and bats:

North American Bats Face Possible Endangerment

White Nose Syndrome - Revisited

White Nose Syndrome and Evaporative Water Loss

Does Ketosis Occur During Hibernation?

dr. dolittle Thu, 05/09/2013 - 12:15

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