for National Geographic News
Death is the ultimate fate for most bacteria blasted by huge doses of radiation or parched by a severe lack of water. The genetic material irreversibly splinters into hundreds of pieces, dooming the organisms as surely as Humpty Dumpty.
But a few bacteria can "resurrect" themselves by quickly piecing their DNA back together—a strange ability that has mystified biologists for decades.
Now researchers have figured out how one species of these phoenix-like bacteria can rise from the ashes.
A group led by Miroslav Radman, a molecular geneticist at Université René Descartes in Paris, France, announces its findings today on the Web site of the journal Nature.
Radman's group studied a bacteria called Deinococcus radiodurans, which survives in sunbaked deserts and rock surfaces. (Related: "'Miracle' Microbes Thrive at Earth's Extremes" [September 2004].)
The organism can withstand massive doses of radiation and can even survive being completely dried out.
When that occurs, "there is no metabolism," Radman said. "The genome is shattered into hundreds of pieces. It is a dead cell.
"But out of this horrendous damage, it can resurrect."
Keeping It Together
DNA normally acts like a blueprint, telling cells how to cook up the proteins that make life possible (get a genetics overview).
But shredding these instructions renders them useless. Once DNA is split into multiple pieces, there's usually no way a cell's internal machinery can figure out how to piece everything back together again.
Reconstruction must be precise, because a message restitched in the wrong order is gibberish, dooming the organism.
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