A new study shows that tardigrades, also known as moss piglets or water bears, can survive being dried out for more than a decade. The microscopic animals are known to endure and survive hard conditions, and they’ve been scientists’ study subject for more than 250 years.

The study was published in Molecular Science on Thursday by a group of researchers, who discovered the tardigrade’s secret to resisting conditions no other living organisms survive. The tardigrades use a unique set of proteins that researchers named tardigrade-specific intrinsically disordered proteins (TDPs).

Tardigrades, also known as water bears, are almost microscopic animals that can be found on the water film that covers musk or leafs in forests. Photo credit: Unisci / Burnt X

“The big take away from our study is that tardigrades have evolved unique genes that allow them to survive drying out. In addition, the proteins that these genes encode can be used to protect other biological material – like bacteria, yeast, and certain enzymes – from desiccation” explained study’s lead author Thomas Boothby, a member of the Life Sciences Research Foundation Postdoctoral Fellow at the University of North Carolina in Chapel Hill, according to Bioscience Technology.

The study discards previous theories regarding the tardigrades’ surviving skills. Scientists thought that their ability came from a sugar called trehalose, that allegedly gave tardigrades the ability to endure desiccation. Trehalose is found in some organisms that can also tolerate desiccation, such as brine shrimp, yeast, and nematodes.

Biochemical studies of tardigrades have found trehalose, and results have shown little or no trehelose presence in the water bears. The studies involved sequencing techniques, and results revealed that tardigrades do not possess the gene for the enzyme required to produce the sugar.

Searching for the secret ingredient

Boothby and his team set out to discover how did the tardigrades survive if they weren’t using trehalose to prevent being dried out. The research’s first step was to investigate which genes were active in the tardigrades under different circumstances, like drying out, frozen and unstressed.

Doing this, they were able to identify some genes that upregulated when the tardigrades were beginning to dry out. The proteins that those genes encoded were the TDPs, a class of proteins named intrinsically disordered proteins (IDPs). IDPs do not have fixed three-dimensional structures.

The researchers went on to conduct the same experiment in two other species of tardigrades and found the same TDP genes. One species can survive being desiccated the longest, as its genes are active all the time. Boothby believes that this species can do so because it has so many of the proteins available already and it doesn’t need to produce more.

Finally, they went out to discover if the TDPs gave tardigrades their survival ability, and they placed TDPs in yeast and bacteria, finding that the genes also protected those organisms.

Researchers believe that TDPs can be used to guard crops against droughts and some medications that usually need cold storage., for example. TDPs have many potential applications that can help in numerous scientific fields.

“Being able to stabilize sensitive pharmaceuticals in a dry state is very important to me personally. I grew up in Africa, where lack of refrigeration in remote areas is a huge problem. These real-world applications are one of the things that led me to study tardigrades” adds Boothby.

Source: Bioscience Technology