Wednesday, October 16, 2019

Immortal Tardigrades, Can this Help Humans?

There are thousands of people who would like to be like tardigrades. Tardigrades, often called water bears or moss piglets, are near-microscopic animals with long, plump bodies and scrunched-up heads. They have eight legs, and hands with four to eight claws on each. while they are so small and weird looking, they are almost indestructible and can even survive in outer space. According to this article, They can range from 0.05 millimeters to 1.2 mm long, but they usually don't get any bigger than 1 mm (0.04 inches) long. Water bears can survive just about anything. In this article, it states that water bears were resistance to being bombarded with X-rays and being doused in hydrogen peroxide. Such chemical exposure and radiation can result in the production of DNA-damaging hydroxyl radicals, molecules composed of oxygen and hydrogen. All tardigrades require surrounding water to grow and reproduce, but some species—typically those living in the limno-terrestrial environments, have the ability to tolerate almost complete dehydration. When encountering desiccation, tolerant tardigrades lose body water and enter a contracted dehydrated.
But what is behind the protection of these creatures? 
Previous research indicated that a protein for damage suppressor called Dsup, shields the tardigrade species from radiation. Tardigrades are able to withstand extreme conditions because of this unique nuclear protein that binds and forms a protective cloud. In a recent study, it was found that when added to human cells, the protein also protects against radiation. It was unknown whether Dsup binds to chromatin directly or if it protects DNA indirectly, until an experiment showed that Dsup from Ramazzottius varieornatus binds to chromatin to protect the DNA from damage by hydroxyl radicals. Dsup protein in another tardigrade species, Hypsibius exemplaris, also works in a similar way.

The most remarkable feature of the tardigrades is their ability to withstand extremely low temperatures and desiccation (extreme drying). Under unfavorable conditions, they go into a state of suspended animation called the “tun” state—in which the body dries out and appears as a lifeless ball (or tun). Tardigrades can survive as tuns for years, or even decades, to wait out dry conditions. In this state, their metabolism may decline to as little as 0.01 percent of its normal rate. Under normal room temperature, the water bears come to life with the help of helium gas at room temperature.  

A professor at the University of California believes this protection was meant to shield against radiation specifically. They believe it was a survival mechanism against hydroxyl radicals in the "mossy environments that many terrestrial tardigrades inhabit".  When tardigrades enter anhydrobiosis, which is a dormant state induced by drought in which an organism becomes almost completely dehydrated and reduces its metabolic activity to an imperceptible level, it is because the moss dries up. This is when Dsup should help them survive. We hope these findings eventually could help researchers develop animal cells that can live longer under extreme environmental conditions. “In theory, it seems possible that optimized versions of Dsup could be designed for the protection of DNA in many different types of cells,” Professor Kadonaga said.
Posted by Pamela Jimenez  (5)


  1. Water bears! They are so cool, they can even survive in space, with no oxygen. This is really cool that they think they have found out how tardigrades are so resilient. I wonder if Dsup kind of acts like a peptidogylcan cortex of an endosperm.
    Liz Clark

    1. That is a good questions! i think that maybe the peptidogylcan cortex of an endosperm has a gene like the Dsup gene that makes them resistant to extremely high temperatures and ultraviolet radiation.

      posted by Pam