Tardigrades are one of the most strange microscopic animals we know of and a new discovery has effectively taken them up a notch in the strangeness and uniqueness scale.
Tardigrades, which are also known as water bears and moss piglets, have a unique ability to survive in some of the harshest environments in the world. As part of this unique ability, the water bears can endure being dried out for up to a decade or longer and this they achieve through a unique set of proteins which have now been named tardigrade-specific intrinsically disordered proteins (TDPs). These proteins can be used to protect other biological material–like bacteria, yeast, and certain enzymes–from desiccation.
The scientific community has long believed that it was a sugar called trehelose that gave tardigrades the ability to survive extreme dry conditions. The reason behind this assumption was that trehelose is found in a number of other organisms that can survive being dried out, including yeast, brine shrimp, and some nematodes. But it turns out that’s not the case as biochemical studies of tardigrades have found trehelose at low levels or not at all with no genetic evidence either that these organisms have the genome required to make this sugar.
To determine what it was that was providing the tardigrades with the unique ability to survive dry weather, scientists first looked at which genes were active under various conditions: unstressed, drying out, and frozen. Scientists first identified the gene in one of the species of tardigrade and subsequently the same gene was found in other two species as well.
To verify that these TDPs were what gave tardigrades their unique abilities, the researchers put the genes encoding them into yeast and bacteria, and confirmed that the TDPs protected these other organisms.
Trehelose helps other organisms to survive drying out by forming glass-like solids when they dry, rather than crystals. Researchers found that TDFs form similar glass-like solids, and showed that when the glassiness of TDPs was disrupted, it correlated with a loss of their protective abilities. Check out the video below: