Deinococcus radiodurans is probably the closest thing we have to a real superhero; not for nothing was it nicknamed Superbug and Conan the Bacterium. Its super-abilities include unbelievable resistance to radioactivity; immunity from heat, cold and acid; and the ability to survive in outer space.
It was discovered by accident in the 1950s, when a tin of meat was blasted with radiation that was supposed to kill anything living inside. When scientists investigated later, they saw that the meat had spoiled, and growing happily on it was D. rad .
Had it been a movie, D. rad would probably have been wearing full-body tights and bellowing "Mwahaha!"
To give you some perspective, humans would die from exposure to 400-1000 rads of ionising radiation. The humble cockroach, hailed in popular myth as radiation proof, can tolerate 10 times as much. But D. rad puts us all to shame: it thrives happily after being zapped with 1.5 million rads, and can apparently withstand twice that. Mwahaha, indeed.
[Radiation damages DNA inside cells but D. rad has an elaborate repair mechanism, including up to 10 copies of its DNA, only some of which are active at any time and susceptible to damage.]
What use is such a complicated system to this microbe? One possible explanation is that this resistance might be a defence against something a lot more common - lack of water.
Extreme desiccation causes just about the same kind of stress and damage to DNA that radiation does. Long ago, this species may have developed a mechanism for dealing with very dry surroundings that, incidentally, makes it immune to nuclear radiation.
All these capabilities are very convenient for us humans because D. rad is a superhero that uses its powers for good, rather than evil.
It is harmless to humans and animals, it lives peacefully in the soil, and it may well help us clean up the terrible mess that we have foolishly created for ourselves through our development of mixed-waste sites.
We might be able to decontaminate the sites using microbes that break down toxic chemicals, but they would all die from the radiation before they managed to do anything.
Never fear - D. rad to the rescue! Scientists are now trying to take the genes from the bio-remediating microbes and insert them into D. rad . If this works properly, it would be an elegant solution to a very knotty problem.
From Small Wonders: How Microbes Rule Our World by Idan Ben-Barak (Scribe).