Reviewing the "Arseniclife" Paper

Many of you will remember the "arsenic affair" from a couple of years ago. Here's what I wrote in February 2012 once we knew that the main result of the paper had been disproven by Rosie Redfield. We now know that there was no arsenic in the DNA (Erb et al. 2012, Reeves et al., 2012).

The "arsenic affair" began with a NASA press conference on Dec. 2, 2010 announcing that a new species of bacteria had been discovered. The species was named GFAJ-1 (Get Felisa a Job), by the lead author Felisa Wolfe-Simon. GFAJ-1 was grown in a medium that lacked phosphate and contained high concentrations of arsenic. The paper, published that day on the Science website, claimed that arsenic was replacing phosphorus in many of the cell's molecules, including nucleic acids.

Like many other scientists, I was very skeptical from day one. The results reported in the press conference just couldn't possibly be true unless everything we knew about chemistry and DNA was very wrong.

How did this paper ever get published in Science? I was suspicious that the normal peer review process had been skipped in order to get a major discovery into press as soon as possible.

Turns out that wasn't true. There were three reviews and they were all glowing. We know this because USA Today has obtained copies of the reviews through the Freedom of Information Act in the USA [Glowing reviews on 'arseniclife' spurred NASA's embrace] [Excerpts for the "asreniclife" investigation file]. Here are excerpts from the three reviews—I've never seen such glowing reviews.

Review 1

The manuscript Wolfe-Simon et al. demonstrates for the first time that a microorganism is able to use arsenic in place of phosphorus to sustain growth and life. This was done by using a rather simple initial selection on synthetic growth medium followed by a more in-depth analysis of the isolated organism with regard to the path of arsenic from uptake to incorporation into various cellular fractions using ICP-MS, 73As labeling and X-ray absorption near edge spectroscopy (XANES).

The results are exceptional as they show that arsenic, yet believed to be highly toxic for most organisms, in GFAJ-1, a member of the Halomouadaccae, can substitute for the lack of phosphate, a major building block for various macromolecules present in all cells, namely nucleic acids, lipids and proteins.

The methods applied are straightforward. The most surprising and acknowledgeable aspect of the work is its simple approach.

I have only a few minor points regarding the overall presentation.

Review 2

The manuscript by Wolfe-Simon et al. is well-written, concise, to the point and provides exciting novel results. The authors provide many lines of evidence to prove their point that the isolated novel bacterium (at least to some extent) can replace phosphate by arsenic in its biomolecules. It's a pleasure to get a well-conceived and carried-out study to review.

Review 3

Reviewing this paper was a rare pleasure. It is clearly-written and well-reasoned. The authors choose the right methods, designed the right experiments, obtain solid data supporting the conclusion that GSAJ-1 uses As in place of place of P. They use appropriate caution in interpreting results. I think the paper is just about publishable as is; my comments for revision are below. Great job! I look forward to seeing follow-up work in the future.

Looks like we can blame the reviewers, or perhaps the editor for choosing the wrong reviewers.

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[Hat Tip: Michael Eisen (@mbeisen) (#arseniclife)]

Erb, T.J., Kiefer, P., Hattendorf, B., Günther, D., and Vorholt, J.A. (2012) GFAJ-1 is an arsenate-resistant, phosphate-dependent organism. Science, 337: 467-470. [doi: 10.1126/science.1218455 ]

Reaves, M.L., Sinha, S., Rabinowitz, J.D., Kruglyak, L., and Redfield, R.J. (2012) Absence of detectable arsenate in DNA from arsenate-grown GFAJ-1 cells. Science, 337: 470-473. [doi: 10.1126/science.1219861]

Wolfe-Simon, F., Switzer Blum, J., 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. (2011) A bacterium that can grow by using arsenic instead of phosphorus. Science. 332:1163-1166. Published online 2 December 2010; published in Science magazine Jun 3, 2011 [doi: 10.1126/science.1197258]

Posted in: Biochemistry, Science