Sunday, December 5, 2010

Microbiologist: NASA's arsenic bacteria story "shamefully bad science"

Rosie Redfield runs "a microbiology research lab in the Life Sciences Centre at the University of British Columbia."

My main concern up to now with this story was that it was yet another example, so increasingly prevalent these days, of researchers and institutions over-hyping their discoveries so as to attract media attention (and no doubt more funding). And of course the blogosphere and twitterverse had been crackling for days with speculation (fed by NASA) about some amazing discovery with exobiological ramifications.

Bottom line:  Lots of flim-flam, but very little reliable information.  The mass spec measurements may be very well done (I lack expertise here), but their value is severely compromised by the poor quality of the inputs.  If this data was presented by a PhD student at their committee meeting, I'd send them back to the bench to do more cleanup and controls.

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.  The authors have done some of the latter, but not the former.  They should have mixed pregrown E. coli or other cells with the arsenate supplemented medium and then done the same purifications.  They should have thoroughly washed their DNA preps (a column cleanup is ridiculously easy), and maybe incubated it with phosphate buffer to displace any associated arsenate before doing the elemental analysis.  They should have mixed E. coli DNA with arsenate and then gel-purified it.  They should have tested whether their arsenic-containing DNA could be used as a template by normal DNA polymerases.  They should have noticed all the discrepancies in their data and done experiments to find the causes.

I don't know whether the authors are just bad scientists or whether they're unscrupulously pushing NASA's 'There's life in outer space!' agenda.  I hesitate to blame the reviewers, as their objections are likely to have been overruled by Science's editors in their eagerness to score such a high-impact publication.

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