Deinococcus radiodurans -- listed as "world's toughest bacterium" in the Guinness Book of World Records -- may prove useful in future human missions to Mars, according to researchers.
The organism, known also as D. radiodurans, can survive extremely high radiation, as well as toxic chemicals, dryness, and other harsh conditions. It was first discovered in a can of spoiled meat that supposedly had been sterilized by radiation.
Such resilience might prove useful on the red planet. "This bug could provide various forms of protection," says Robert Richmond, a senior scientist at NASA's Marshall Space Flight Center. For instance, says Richmond, a genetically engineered version of D. radiodurans might be scattered in Martian soil to make the soil less corrosive to spacesuits and equipment.
Organisms that survive in tough environments are called "extremophiles." Richmond, coining a new term, calls D. radiodurans a "polyextremophile," because it can endure a broad range of harsh conditions.
Efforts already are under way to engineer D. radiodurans for useful tasks on Earth, such as cleaning up radiation at sites once used for testing nuclear weapons. The bacterium "is exquisitely suited to living in harsh environments," says Michael Daly, an assistant professor at the Uniformed Services University of the Health Sciences in Bethesda, Maryland. Daly has worked for 8 years on genetic engineering of the microbe.
The idea of using D. radiodurans on Mars was presented in a recent paper by Richmond, Daly, and Raj Sridhar, a radiation oncologist at Howard University Medical Center.
Changing the Martian soil is only one of the bacterium's potential uses contemplated by the team. Another possibility, says Richmond, is that genetic engineering of D. radiodurans will lead to drugs that can endure under Martian conditions. "You can't take a pharmacy to Mars," he notes.
Studying the bacterium is also useful as a way to figure out what type of native life might exist on Mars -- and whether to worry about contaminating Earth with a Martian organism. Daly recently cautioned a NASA panel that irradiation might not be sufficient to sterilize samples from future Mars missions. After all, he pointed out, such treatment would not kill D. radiodurans.
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