Extreme Physiology: Radiation tolerance

Don't let their small size fool you. Tardigrades, or 'water bears', are really tough animals. According to a review published in the American Scientist, these microscopic invertebrates can survive extreme variations in temperature from near absolute zero (-459 deg F) up to +302 deg F. They can also tolerate pressures that are 6 times greater than the deepest ocean, exposure to ionizing radiation (UV and x-ray) and the vacuum of space, as well as exposure to carbon dioxide and monoxide, nitrogen and sulfur dioxide. What's more, they can survive nearly complete dehydration, an ability called anhydrobiosis. To survive these extreme challenges, the animals go through a state called cryptobiosis during which time they shut down metabolism until the threat is over. For animals that live in moist environments with periodic dry spells, dehydration is a threat.

A new study published in Nature Communications examined whether water bear cellular tolerance to dehydration and radiation could be transferred to human cells. The researchers suspected that because both these threats damage DNA, water bears may use the same protein to protect their tissues. The team sequenced the genome of a species of water bear (Ramazzottius varieornatus), then inserted portions of the genome into cultured human cells. Just as they had suspected, they discovered a gene called Dsup that can prevent DNA damage caused by exposure of the cells to x-rays as well as dehydration.

The hope is that this discovery may lead to therapies to help protect people receiving radiation therapy or those who work with radiation. It may also help in the development of crops that can tolerate extreme temperatures or radiation - farming on Mars anyone?

Given their amazing tolerance to extreme environments, I am sure the water bear genome sequence will lead to additional discoveries of protective proteins.



American Scientist

Video By Halberg K, J?rgensen A, M?bjerg N [CC BY 4.0 (http://creativecommons.org/licenses/by/4.0)], via Wikimedia Commons

More like this

Water bears, aka tardigrades, are resilient little creatures. These microscopic animals can survive both freezing and boiling temperatures, radiation, high pressure, starvation, the vacuum of space and even desiccation. This last ability caught the attention of a team of researchers interested in…
Bdelloid rotifers are one of the strangest of all animals. Uniquely, these small, freshwater invertebrates reproduce entirely asexually and have avoided sex for some 80 million years. At any point of their life cycle, they can be completely dried out and live happily in a dormant state before being…
In September last year, a team of scientists launched a squad of tiny animals into space aboard a Russian satellite. Once in orbit, the creatures were shunted into ventilated containers that exposed them to the vacuum of space. In this final frontier, they had no air and they were subjected to…
It was a wet and rainy day yesterday, and we have a dissecting microscope, so I decided to see if I could find some tardigrades. Tardigrade photo by nebarnix Reposted from Nov. 2006 I went outside and scraped a bit of moss and some lichens off of our deck. Then I put the lichens and moss in a…