Do bacteria cozy up for the winter?
With the winter rapidly approaching, as it is in the Northern Hemisphere, there may be days when you’re not only reluctant to get out of bed, but are actually downright drawn to the idea of hibernating.
Scientists refer to hibernation as “dormancy,” a period in an organism’s life-cycle when growth and development are temporarily stopped.
So, what about bacteria? Do they hibernate?
Well, we’ll get there in a moment, but before we do, we must salute nature’s champion hibernator.
Let’s hear it for the Edible Dormouse.
A 2015 study found that these little rotund rodents often continue hibernating underground even after the cold conditions end.
In fact, the gold medal was awarded to one particular specimen that indulged in an epic 11.4 month sleepathon, which means it was only actually awake for just over two weeks that year.
By the way, if you’ve ever wondered how the Edible Dormouse got its name, it’s because the Romans first gave them that label after they farmed and ate the little critters, often as a mere snack.
So the next time you have a bad day, thank your lucky stars that at least you aren’t from a species with “edible” in its name.
Let’s return our focus to bacteria, for it seems that they can indeed exhibit several forms of dormancy.
One mechanism is the ability of some species to form what are called endospores.
Endospores are an inactive form of bacteria with the ability to survive for extended periods without nutrients.
They can be resistant to extreme cold, many disinfecting chemicals, and even radiation levels that would have normally doomed them.
Scientists who studied the bacterial species Bacillus subtilis found that an endospore is formed when one bacterial cell divides into two.
One of these cells remains bacterial, while the other becomes a kind of tough shell that surrounds and protects its vulnerable inhabitant.
Endospores may be able to survive for years, which may be food for thought when you learn that some endospore-forming bacteria include those responsible for diseases such as anthrax, botulism, gangrene, and tetanus.
Endospores aren’t the only means by which bacteria can go into a kind of suspended animation.
A couple years ago, Spanish researchers discovered that when they introduced E. coli cells into a droplet of saltwater, which was then allowed to evaporate, the bacterial cells built a kind of crystalline “house” around themselves in which they could lay dormant until they were revived through the addition of water.
The research was published in the intriguingly-titled journal “Astrobiology,” dedicated to “advancing the understanding of life’s origin, evolution, and distribution in the universe.”
Why on earth would research such as this be published in a journal about extraterrestrial life, when the experiments were actually carried out in the Spanish city of Valladolid?
Well, the scientists explained that understanding this kind of mechanism might help us find signs of life on other planets.
Before we leave the subject of bacteria and hibernation, let’s end with the results of a fascinating Swedish study showing that the gut microbiome of the brown bear changes in winter in a way that helps the creatures cope with hibernation.
Just like many hibernating animals, bears feast in the warmer months, putting on weight that keeps them going through their winter sleep.
Scientists from the University of Gothenburg found that the microbial composition of a bear’s gut shows profound seasonal change.
When they transferred bear bacteria into germfree mice (yup, yet more rodents), mice who got “summer bacteria” experienced greater fat gain than those who received “winter bacteria.”
The leader of the research, Professor Frederick Bäckhed, said that the findings unfortunately wouldn’t help tackle human obesity, but could possibly provide clues for treating malnutrition in patients with cancer or anorexic disorders.
The bewilderingly brave team of researchers on the project faced dangers not normally experienced in microbiology experiments.
Starting in the winter months, they located 16 hibernating wild bears, who were tranquilized in their dens in order to collect blood and fecal samples.
In case you wondered, hibernating bears don’t actually poop in the woods.
No, the scientists had to go in through the back door, as it were, to gather their samples.
So would you put your hand up a wild bear’s…? Never mind.
The final step involved fitting each bear with a GPS collar, then returning it to its den, so it could wake up naturally and unsuspectingly in the spring.
The following summer, the bears were tracked by helicopter, shot with a tranquilizer from the air, then subjected to another round of blood and fecal sampling.
Quite an elaborate process, you may agree.
Thankfully, when you have your own microbiome analyzed by uBiome, you’ll be relieved to know that we won’t be sending round a guy in a helicopter with a tranquilizer gun. All you need to do is lightly swab a piece of used toilet paper.