These Muppet-like creatures are able to survive extreme conditions, including staggering amounts of radiation, temperatures 302 degrees Fahrenheit to nearly absolute zero, and pressures that would beat those in the deepest ocean trenches.
Tardigrades have been around for 530 million years and outlived the dinosaurs.
Tardigrades are microscopic animals, otherwise known as water bears, that are known for their freakish characteristics, including the ability to stay dried out, and bisexual mating tendencies. If there's an animal that knows how to make it against all odds, it's this guy and, as you might imagine, a lot of people are interested to find out what its secret weapons are. In this form, neither heat, cold or the wretched vacuum of space can kill it.
When they're frozen, the creatures enter a state called cryptobiosis, in which their metabolic processes shut down, and they show no visible signs of life.
Now, researchers from the University of North Carolina at Chapel Hill have found another ace up the water bear's sleeve.
It's when water bears are thrust in a dry environment that the proteins transform into a glass-like sanctuary that covers the dehydration-sensitive parts of the tardigrade from danger. This way, sensitive proteins and other biological molecules are locked in place.
Their cute physiognomy and ability to survive the harshest of circumstances have made them the darling agents of microbiologists.
Microscopic creatures called water bears were discovered to live without water. Meanwhile, they carefully monitored the animal's gene activity.
TDPs, it turns out, create "a glass-like matrix within cells, physically preventing protein denaturation, protein aggregation, and membrane fusion", to quote Boothby's paper. When such genes were blocked through genetic engineering, the tardigrade died of dehydration.
Behold the mighty tardigrade, quite likely the toughest creature on Earth.
Boothby argued that the genes which contained the disordered protein occurred when they were trying to establish which genes were activated during the drying process. California's worst drought in history, which is still not over and sure as heck isn't the last, serves as a reminder that such crops are badly needed.
The study discards previous theories regarding the tardigrades' surviving skills. "These real-world applications are one of the things that led me to study tardigrades" adds Boothby. Unlike other known proteins, TDPs are jelly-like in the water and do not become well-defined three-dimensional structures. Boothby cited it as an example of convergent evolution, which is when evolution comes up with similar solutions multiple times.
Another water bear trick involves using other proteins to shield its DNA against radiation. Through this method, they identified the specific genes that are expressed at high levels in the drying out phase, and the proteins those genes encode.
The IDPs found in tardigrades have been named tardigrade-specific intrinsically disordered proteins (TDP) and they were found in another species that also survives drying out. A much farther away application might involve dehydrating people to induce a hibernation-like state, which could be useful in interstellar flight.
Water bears that lacked functional IDPs couldn't survive extremely dry conditions, as the biochemists noted in a study published Thursday in Molecular Cell.