In 2011, researchers had discovered a bacterium that uses arsenic in the place of phosphorus – one of six elements previously thought indispensable for all life forms. The strain has been dubbed GFAJ-1. Its a rod-shaped bacterium in the family Halomonadaceae.
The word GFAJ stands for "Give Felisa a Job," Felisa being the author of the first paper on GFAJ-1. It is a strain of rod-shaped bacterium microbe member of a common group of bacteria, the Gammaproteobacteria. Studies claimed that it is capable of living in environments with extremely high salt concentrations that would kill most other bacteria. GFAJ-1 is able to produce osmoprotectants which build up in the organism’s cytoplasm along with other ions to deal with the hypotonic environment and ultimately protect against high salt levels The species was originally isolated from Mono Lake, California by microbiologist Felisa Wolfe-Simon, a NASA astrobiology fellow. GFAJ-1 uses arsenic in place of phosphorus to support life. Initial studies also claimed that GFAJ-1 was able to grow and reproduce using and incorporating arsenic into cell mass in place of Phosphorus.
However, the same bacterium was again in news in July 2012 as a group of Researchers University of British Columbia in Vancouver, Canada claimed that no detectable arsenate in the DNA of GFAJ-1, and demonstrated that GFAJ-1 is simply an arsenate-resistant, phosphate-dependent organism making earlier claims a mere speculation.