Sunday, December 05, 2010

Arsenic and Bacteria

The blogosphere is not happy with the recent announcement by NASA of bacteria that are able to "thrive and reproduce using the toxic chemical arsenic." [NASA-Funded Research Discovers Life Built With Toxic Chemical]
This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth. The research is published in this week's edition of Science Express.
I read the paper (Wolfe-Simon et al., 2010) and I can assure you that nothing in that paper is going into my biochemistry textbook. I predict that a year from now we'll have forgotten about this discovery. I'm not even sure it's going to be confirmed but, if it is, the result is pretty trivial.

For a start, even the title of the paper is misleading. The title says "A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus" but all of the data show that there was phosphorus in the media and that the bacteria used it for growth and reproduction. This selected strain of bacteria incorporated more arsenic than non-selected species but it by no means did it replace all phosphate with arsenic. Only a few percent (at most) of the phosphorus atoms in DNA, for example, were replaced by arsenic.

The purpose of this posting it to alert you to a fantastic article by microbiologist Rosie Redfield at the University of British Columbia. I strongly urge that everyone read her take-down of the science paper [Arsenic-associated bacteria (NASA's claims)]. The problem is not just that a bad paper was published in Science—it's that the paper was so heavily promoted in the media. We've got to do better when it comes to educating the general public about science.

Wolfe-Simon, F., Blum, J.S., Kulp, T.R., Gordon, G.W., Hoeft, S.E., Pett-Ridge, J., Stolz, J.F., Webb, S.M., Weber, P.K., Davies, P.C.W., Anbar, A.D., and Oremland, R.S. (2010) A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus. Science Published Online 2 December 2010 [DOI: 10.1126/science.1197258]


  1. When I heard of the upcoming NASA news conference, I decided not to bother watching. This isn't because of any suspicion of NASA. It is just that I expected that it would be overhyping something relatively mundane. The whole purpose of a news conference is to overhype anyway. And if there were something really exciting, it probably would have leaked long before the press conference announcement.

    After hearing about what was reported, it still seemed rather mundane. Mildly interesting, but unsurprising. And there was a disappointing vagueness about the way that arsenic was incorporated into the organisms.

    Thanks, Larry. I appreciate your assessment. We clearly need more skeptical science reporters.

  2. 'Science' and 'Nature' are apparently the PEOPLE/US/In Touch/TMZ of science now.

    Sensationalism is what matters, not the science.

    Its pretty reliable, at this point, that anything they publish regarding HIV is crap. The 'real' science is in the meat-and-potatoes journals.

  3. I am glad you posted the link to the review; one hears the "gee-whiz" as a lay person, listens to "Science Friday" and "Quirks and Quarks", reads the news and assumes things must be solid. So a more detailed and skeptical analysis puts things into perspective.

  4. But how do we counter NASA's publicity juggernaut? I don't blame the media for being swept away by it.

  5. It is interesting to read the post on this over at Panda's thumb, then watch the comment thread as these skeptical reviews are posted.

  6. Redfield: "There's a difference between controls done to genuinely test your hypothesis and those done when you just want to show that your hypothesis is true."

    This is a point that has been almost completely lost in biomedical science today.

  7. Science and Nature have long been the "gee whiz" or superlative (biggest, fastest, strongest, bad assest, etc.) publishers in paleontology and functional morphology. Glad that other fields are finely catching up to their lead.

  8. @Prof. Redfield:
    I believe your best bet in derailing the juggernaut would be satire. If Saturday Night Live were to do a sketch on it that would generate massive embarrassment. AND there would be little to no heat in retribution.

    For as a researcher you do have to be careful when "tackling" a government agency, you might find yourself suddenly bereft of funding.

    Also the sketch could be easily accessible to the general audience (and damn funny) if it's just written right. Say NASA executives brainstorming on hoaxes to feed the masses in order to ramp up funding. "But how will we get that crap published?" "Golden NASA stamp of credence - makes any shit fly by."

    And before you "tch" me, I guess PZ Myers or Richard Dawkins could set up a phone call with Tim Minchin or Bill Maher.

    On a smaller scale there are excellent science journalists who can spread the word. For example Peter Hadfield AKA Potholer54 has carved up quite a reputation.

  9. As a bench molecular biologist with a strong and abiding interest in astrobiology and space exploration, I wrote about this on Friday, as soon as I had read the Science paper: Arsenic and Odd Lace. Then I saw several additional critiques, including Rosie's, and was glad to know I was not alone in seeing glaring holes in that paper -- and no definitive proof that we're dealing with anything but a hardy extremophile.