Gut microbes give some squirrels a serving to hand to remain robust throughout hibernation. The microorganisms seem to assist the squirrels recycle vitamins to maintain the rodents’ muscular tissues taut, researchers report within the Jan. 28 Science.
Understanding how squirrels hold their muscle over the winter may supply a small clue to determining methods to stave off muscle loss for people who find themselves malnourished or have muscle-wasting ailments, the scientists say.
“After long bed rest, humans are just not jumping up and down and climbing mountains,” says research coauthor Hannah Carey, a hibernation physiologist on the University of Wisconsin-Madison. “But that’s what these [squirrels] have to do.”
Muscle breakdown from inactivity or hunger releases compounds made from nitrogen — an important factor present in muscle constructing blocks referred to as amino acids. Too a lot nitrogen might be poisonous, so the physique usually eliminates the surplus by means of urine in a compound referred to as urea.
Previous work has proven that arctic floor squirrels (Urocitellus parryii) can recycle nitrogen for muscle preservation on their very own, with out intestine microbes’ assist (SN: 12/16/20). In the brand new research, Carey and colleagues tracked the place nitrogen went within the our bodies of thirteen-lined floor squirrels (Ictidomys tridecemlineatus) utilizing an isotope, a type of the factor with a special mass, as a tracer. In hibernating squirrels, nitrogen that had been processed by microbes ended up in skeletal muscle. But animals handled with antibiotics to filter out gut-inhabiting micro organism included much less nitrogen into muscle, an indication that the microbes had been accountable.
Some intestine microbes salvage nitrogen from urea and use it to make amino acids. Hibernating squirrels can then use these amino acids to protect muscle, the findings counsel.
It appears that to assist the creatures keep robust, Carey says, microbes and squirrels come collectively.