So, this morning we learned that NASA is about to announce they’ve discovered a new life form here on earth. But then we learned that the truth, though not as exciting in some regards, is even stranger.
Wolfe-Simon and her colleagues designed an experiment to take a particular type of salt-loving bacteria called GFAJ-1 from Mono Lake’s mud sediments, wean it off phosphorus, and see if it could switch its diet to arsenic. In the paper published today, the researchers report that some of the bacteria could survive on arsenic and incorporate it into their cellular biochemistry. Instead of the usual phosphate-rich DNA, they observed arsenate-rich DNA. Heightened levels of arsenic also showed up in the cell’s proteins and fats. The scientists used mass spectroscopy, radioactive labeling and X-ray fluorescence to confirm that the arsenic was really being used in the biomolecules rather than merely contaminating the cells.
This just blows my mind. I mean, it blows my mind that there might be forms of arsenic-life around here that we just haven’t found. That’s weird enough. But there’s something truly weird about being able to switch an organism from phosphate to arsenic.
I know science-folks are probably already laughing, but if there’s one thing you can say about life, it’s that nothing is ever settled. You’d think that phosphorus v. arsenic would be something a life-form would just have to choose at the moment of existence and stick with it. But no. We may find that some can switch back and forth.