Tardigrades are water-dwelling animals that are no longer than a millimeter but can withstand severe conditions that many other animals– are any form of life for that matter– could not. Scientists boggled by the question of ‘how’ released a new study this week sharing newfound secrets about what makes this possible for these tiny creatures.
Also referred to as “water bears” or “moss piglets,” Tardigrades are bulky looking animals that live in water film and in spaces found between sediment grains.What makes this creature so unique is its ability to become dormant for extended periods of time in order to survive extreme environmental states, such as freezing temperatures and desiccation–a state of extreme dryness.
“In recent years humans have been pretty mean to them: drying them out slowly and quickly, freezing them solid, autoclaving them, exposing them to the vacuum of space and cosmic rays, irradiating them,” Mark Blaxter, professor at the University of Edinburgh’s Institute of Evolutionary Biology, told CNN. “I am sure someone has put them under extreme pressure, maybe even tried really bad music at high volumes, or biting insults.”
This creature tiny creature has eight legs with claws at the end, a brain and central nervous system and something sucker like called a pharynx that it uses to eat. With features making it part arthropod and part nematode, there are nearly 12,000 species of tardigrades, which include marine, freshwater and terrestrial species, the study states.
For this particular study, a team including Baxter examined two species of tardigrades and how each reacted to desiccation. The first type of tardigrade the researchers used is called H. dujardini and the second is called R. varieornatus. The first type is a limnoterrestrial tardigrade and the other a terrestrial tardigrade that is highly tolerant of environmental extremes, according to the researchers.
While both species can endure extreme dryness, the researchers found one big difference between how fast each did. “What we found very interesting was that our two tardigrades use similar proteins but do things differently,” Blaxter told CNN. “Ramazzottius is able to withstand drying at zero notice. The pond tardigrade Hypsibius needs warning. If we dry it up rapidly it doesn’t survive, but if we give it 24 hours warning — by exposing it to a drying atmosphere — it does OK. Hypsibius has to turn on genes in order to survive drying, but Ramazzottius has already got the necessary proteins made.”
The difference in pace may relate to each species typical habitat; R. varieornatus is often found in moss on concrete roads and can dry out within 30 minutes, while H. dujardini lives in ponds and takes 24 to 48 hours to dry, New Scientist reported.
How do tardigrades survive extreme conditions?
The animals rely on a protein unique to them called tardigrade-specific intrinsically disordered proteins (TDPs), according to a study on tardigrades, which was published in the Molecular Cell journal in March. When water is present these protein are jelly-like and don’t form into well defined three-dimensional structures, New Scientist reported. But when that water starts to dry out, these proteins become like a glass-like and protect all dehydration-sensitive materials in the animal from harm.
“When the animal completely desiccates, the TDPs vitrify, turning the cytoplasmic fluid of cells into glass,” Thomas Boothby of the University of North Carolina at Chapel Hill, and lead author of that study said. “We think this glassy mixture is trapping [other] desiccation-sensitive proteins and other biological molecules and locking them in place, physically preventing them from unfolding, breaking apart or aggregating together.”
Tardigrades could help humans
If scientists are able to get to the bottom of how this creature manages to survive water free, this could offer new ways to preserve and transport vaccines across the world, Blaxter says.
“Tardigrades can tell us about how some fundamental biological problems have been solved, like how to preserve cell structures including DNA without any water present in the cell,” Ingemar Jönsson at Kristianstad University in Sweden told New Scientist. “We can learn a lot from these animals, and there is an obvious potential for applications in medicine and biotechnology.”
These little creatures could quite possibly help in humans in numerous ways– but first researchers still have to find out what exactly this creature is.
