Resurrecting" Bacteria's Secret Revealed
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 Universit� Ren� 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.
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. DNA normally acts like a blueprint, telling cells how to cook up the proteins that make life possible. 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.
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 Universit� Ren� 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.
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. DNA normally acts like a blueprint, telling cells how to cook up the proteins that make life possible. 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.
Largest Known Planet Discovered, Astronomers Announce
Astronomers say they have discovered what appears to be an entirely new kind of planet, an extra-large gas giant unlike any known world in our solar system or beyond.
The planet, dubbed HAT-P-1, is located some 450 light-years from Earth in the constellation Lacerta. It is the largest planet ever discovered and boasts a radius nearly 1.4 times larger than Jupiter's. HAT-P-1 is also the least dense of all known planets.
"This planet is about one quarter the density of water," said Gaspar Bakos, a Hubble fellow at CfA.
In other words, it's lighter than a giant ball of cork. Just like Saturn, it would float in a bathtub if you could find a tub big enough to hold it, but it would float almost three times higher. The planet's large size and low density can't be explained by current theories of giant planet formation.
Scientists suggest that additional heat in its interior could account for its "puffed-up" size, but as yet they can't explain how such heat could be generated.
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