New Life Form Lives on ArsenicBy Irene Klotz, Discovery News
 Strange bacteria living deep in a California lake can survive on arsenic and can even grow by incorporating the element into its DNA and cell membranes. GFAJ-1 is no Frankenstein monster. It's a bacterium scooped up from the salty sediments of Mono Lake in California that seems to have pulled off a major scrambling of its building blocks for life -- something scientists didn't think possible. The finding not only presents the possibility that alternative life forms can exist, or once existed, on Earth. It also muddies the waters for scientists refining techniques to identify alien life, if it exists. "The implications are profound, regardless. The building blocks of life are more flexible that we had previously thought and that's an important concept to realize as we pursue the search for life beyond Earth," astrobiologist Ariel Anbar, with Arizona State University, told Discovery News. The life forms in question, GFAJ-1 of the Halomonadaceae family of Gamoproteobacteria -- like all living things -- were dependent on oxygen, carbon, hydrogen, nitrogen, phosphorus and sulfur to exist. But in the laboratory of Felisa Wolfe-Simon, a NASA astrobiology research fellow at the U.S. Geological Survey in Menlo Park, Calif., the organisms learned to live with arsenic instead of phosphorus. "Are the organisms actually doing this in Mono Lake, or do they have the latent ability to do so? Or, is this evolution in the lab? That's an interesting question to pursue," Anbar said. Analysis showed the transition was more than cosmetic. The microbes seem to have incorporated arsenic into their DNA. Wolfe-Simon accomplished this by gradually reducing the levels of phosphorus available to the colony, forcing them to make do, or die, in a medium that became increasingly more concentrated in arsenic, which from a molecular perspective, closely resembles phosphorus. Surprisingly, the colony lived and grew. Colleagues at Arizona State published a paper in January speculating that early life on Earth may have thrived in the arsenic-rich environments of the planet's early oceans. Some organisms may still do so in unusual environments today. Wolfe-Simon's research appears in this week's Science. |
advertisement
Related LinksMore on NASA's discovery, ETs and the origin of life Watch NASA's Full Announcement Through the Wormhole Build Your Own Power Planet
|
-
our sites
-
video
-
shop
-
stay connected
-
corporate
