October 10, 2008
Bioengineering Professor Adam Arkin was involved in the genome sequencing analysis of the first ecosystem ever found having only a single biological species, discovered 2.8 kilometers (1.74 miles) beneath the surface of the earth in the Mponeng gold mine near Johannesburg, South Africa.
There the rod-shaped bacterium Desulforudis audaxviator exists in complete isolation, total darkness, a lack of oxygen, and 60-degree-Celsius heat (140 degrees Fahrenheit).
D. audaxviator’s unusual genome was sequenced and analyzed using the techniques of environmental genomics, also called metagenomics, which allows researchers to use known information about other organisms to figure out how this organism’s metabolism functions.
D. audaxviator survives in a habitat where it gets its energy not from the sun but from hydrogen and sulfate produced by the radioactive decay of uranium. Living alone, D. audaxviator must build its organic molecules by itself out of water, inorganic carbon, and nitrogen from ammonia in the surrounding rocks and fluid. During its long journey to the extreme depths, evolution has equipped the versatile spelunker with genes – many of them borrowed from archaea, members of a separate domain of life unrelated to bacteria – that allow it to cope with a range of different conditions, including the ability to fix nitrogen directly from elemental nitrogen in the environment.
Sequencing and analysis was done by scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), Joint Genome Institute (JGI), and Pacific Northwest National Laboratory (PNNL), working with colleagues from Princeton University, Indiana University, National Taiwan University, Massachusetts Institute of Technology (MIT), Florida State University, the Desert Research Institute, and the University of Western Ontario. The work was a project of the Virtual Institute for Microbial Stress and Survival (VIMSS), directed by Berkeley Lab’s Adam Arkin and Terry Hazen, and the Indiana Princeton Tennessee Astrobiology Initiative (IPTAI) of NASA’s Astrobiology Institute. The researchers report their results in the 10 October, 2008 issue of the journal Science.
Read the full story at Lawrence Berkeley Lab.