A bacterium that some scientists thought could use arsenic in place of phosphorus in its DNA actually goes to extreme lengths to grab any traces of phosphorus it can find.
The finding clears up a lingering question sparked by a controversial study, published in Science in 2010, which claimed that the GFAJ-1 microbe could thrive in the high-arsenic conditions of Mono Lake in California without metabolizing phosphorus — an element that is essential for all forms of life.
Although this and other key claims of the paper were later undermined (see 'Study challenges existence of arsenic-based life'), it was not clear how bacteria discriminate between nearly identical molecules of phosphate (PO43-) and arsenate (AsO43-).
The finding clears up a lingering question sparked by a controversial study, published in Science in 2010, which claimed that the GFAJ-1 microbe could thrive in the high-arsenic conditions of Mono Lake in California without metabolizing phosphorus — an element that is essential for all forms of life.
Although this and other key claims of the paper were later undermined (see 'Study challenges existence of arsenic-based life'), it was not clear how bacteria discriminate between nearly identical molecules of phosphate (PO43-) and arsenate (AsO43-).
