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Is Arsenic the new link in the chain of life?
By siliconindia
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Friday, 03 December 2010, 18:21 IST
Bangalore: Until now, all organisms were thought to have six essential elements in common: oxygen, hydrogen, nitrogen, sulfur, carbon and phosphorus. But now researchers have found that bacteria can also survive and grow on arsenic, a deadly poisonous chemical. Researchers said that arsenic was not only showing positive results in their working biology but also it played major role in the DNA structure reports ROBERT LEE HOTZ for The Wall Street Journal.
Normally, organisms use phosphate to build the spiral molecular ladder that cradles the universal genetic code. These molecules use arsenic in its place. That suggests a new element in the building blocks of life.
"It is building itself out of arsenic," said geo-microbiologist Felisa Wolfe-Simon at NASA's Astrobiology Institute and the U.S. Geological Survey, who led researchers from eight federal and university laboratories conducting the experiment. "All life we know is the same biochemically, and this is a little different. It is suggesting there is another way to be alive."
Microbes in common are found in rocks,a mile under the ground or in the clouds. Some bacteria are also seen to thrive in toxic waste or survive in brine five times as salty as the sea. Many species among them which are single-cell creatures also readily grow in the absence of oxygen, warmth and light.
However, they were all thought to share the same biochemistry, based on the Big Six, to build proteins, fats and DNA. "This will fundamentally change our definition of life and how we look for it," said astrobiologist Pamela Conrad at NASA's Goddard Space Flight Center in Greenbelt, Md. "This is a huge deal."
Their finding comes as the hunt for Earth-like planets accelerates. With 22 space-based observatories and 100 ground telescopes, researchers are scanning tens of thousands of stars for evidence of a planet that could support life like that on Earth. Scientists have speculated that an alternative scheme of biochemistry could give rise to other kinds of life in the solar system or on one of the 504 planets astronomers have discovered so far around other stars.
