Alaska Frog's Ability to Survive Record Cold Extremes May Reveal How to Preserve Organs (VIDEO)
Freezing isn't normally a good thing. For frogs in Alaska, though, this is just a normal part of the year. Scientists have found that freezing and thawing may help wood frogs each autumn as they prepared to survive Alaska's cold winter.
"Alaska wood frogs spend more time freezing and thawing outside than a steak does in your freezer and the frog comes back to life in the spring in better shape than the steak," said Don Larson, lead author of the new paper, in a news release.
Wood frogs are somewhat unusual amphibians. They're freeze-tolerant, which means that they can manage to live through harsh winters. In subarctic Interior Alaska, these animals overwinter in the ground covered by duff and leaf litter, which creates a hibernacula. There, temperatures can remain below freezing for more than six months with minimum temperatures of minus four degrees Fahrenheit.
The frogs, though, have some natural adaptations that allow them to survive. They pack their cells with glucose, which is a type of sugar; this reduces drying and stabilizes cells in a process called cryoprotection. In fact, scientists found that glucose concentrations in the frogs were 13-fold higher in muscle tissue, 10-fold higher in heart tissue and 3.3-fold higher in liver tissue compared to lab-frozen frogs.
"In the field in early Autumn it's freezing during the night, thawing slightly during the day, and these repeated freezing episodes stimulate the frogs to release more and more glucose," said Larson. "It's not warm enough for long enough for the frog to reclaim much of that glucose and over time it accumulates giving the frog more protection against cell damage."
The findings reveal how these frogs manage to survive these harsh conditions. Not only that, but freezing frogs may one day have application in the science of human organ transplantation. If researchers can find out how to freeze organs without damage, it could give them a way to preserve organs for longer in order to get them to patients in time.
The findings are published in the Journal of Experimental Biology.
Want to learn more? Check out the video below, courtesy of YouTube.