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|Subject: ~~NASA~~ discovers new unique life form~~ Fri Dec 03, 2010 8:43 am|| |
A strange, salty lake in California has yielded an equally strange bacterium that thrives on arsenic and redefines life as we know it, researchers reported on Thursday.
The bacteria do not merely eat arsenic -- they incorporate the toxic element directly into their DNA, the researchers said.
The finding shows just how little scientists know about the variety of life forms on Earth, and may greatly expand where they should be looking for life on other planets and moons, the NASA-funded team said.
The lake is teeming with life, but not fish. It also contains the bacteria.
"Life is mostly composed of the elements carbon, hydrogen, nitrogen, oxygen, sulfur and phosphorus," the researchers write in Science.
These six elements make up the nucleic acids -- the A, C, T and G of DNA -- as well as proteins and lipids. But there is no reason in theory why other elements should not be used. It is just that science never found anything alive that used them.
The researchers grew microbes from the lake in water loaded with arsenic, and only containing a little bit of phosphorus.
The GFAJ-1 strain of the Halomonadaceae grew when arsenic was in the water and when phosphorus was in the water, but not when both were taken away. And it grew even with "double whammy" of arsenic.
"It grew and it thrived and that was amazing. Nothing should have grown," Wolfe-Simon told a news conference.