Breaking all of life's rules: scientists discover bacteria that can survive on arsenic
While for days rumors have circulated around the Internet that NASA had discovered alien life, the truth may be even less expected. Instead of aliens, NASA-funded researchers have discovered a microorganism on Earth that breaks all the rules of life: in Mono Lake in California scientists found a bacterium that can survive wholly on arsenic. The microorganism is capable of replacing phosphate, one of the essential blocks of all known life, with the toxic chemical arsenic according to new researched published in Science. Uncovered by lead author and NASA-funded scientist, Felicia Wolf-Simon, along with astrobiolgist colleagues at Arizona State University, the discovery is thought to have widespread implications on how life may survive on other planets.
"Life as we know it requires particular chemical elements and excludes others," explains co-author Ariel Anbar, a biogeochemist and astrobiologist who directs the astrobiology program at Arizona State University. "But are those the only options? How different could life be?"
Very, very different it turns out. Arsenic is usually highly toxic to life by disrupting metabolic pathway, however chemically arsenic acts similarly to phosphate. The extremophile bacteria, a member of the Halomonadaceae family, is capable of switching out phosphorous for arsenic to such an extent that the arsenic is actually incorporates it into its DNA.
"Arsenic is toxic mainly because its chemical behavior is so similar to that of phosphorus. As a result, organisms have a hard time telling these elements apart. But arsenic is different enough that it doesn't work as well as phosphorus, so it gets in there and sort of gums up the works of our biochemical machinery," explains Anbar.
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