NASA's 'Arsenic Microbe' Science Under Fire

radioweather writes "The cryptic press release NASA made last week that set the blogosphere afire with conjecture, which announced: 'NASA will hold a news conference at 2 p.m. EST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life.' may be a case of 'go fever' science pushed too quickly by press release. A scathing article in Slate.com lists some very prominent microbiologists who say the NASA-backed study is seriously flawed and that the finding may be based on something as simple as poor sample washing to remove phosphate contamination. One of the scientists, Shelley Copley of the University of Colorado said 'This paper should not have been published,' while another, John Roth of UC-Davis says: 'I suspect that NASA may be so desperate for a positive story that they didn't look for any serious advice from DNA or even microbiology people,' The experience reminded some of another press conference NASA held in 1996. Scientists unveiled a meteorite from Mars in which they said there were microscopic fossils. A number of critics condemned the report (also published in Science) for making claims it couldn't back up."

Re:Papers and Questions

[__aagctu1952]

So my question is basically what does it matter what they grew or washed the bacteria with when, in one of the many investigations, they found that gel purified genomic DNA had elevated levels of arsenic in them? Unless I'm misunderstanding what 'gel purified genomic DNA' means, I would assume that there's still several pieces of data in these experiments that point toward an organism that uses arsenic in place of phosphorous -- even if only somehow partially. Would this sort of spectrometry reveal any arsenic at all in my gel purified genomic DNA?

From Rosie Redfield's critique [blogspot.com]:

Could 400 atoms of arsenate per genome be due to carryover of the arsenate in the phenol-chloroform supernatant rather than to covalent incorporation of As in DNA? The Methods describes a standard ethanol precipitation with no washing (and no column purification which would have included washing), so I think some arsenate could easily have been carried over with the DNA, especially if it is not very soluble in 70% ethanol. Would this arsenate have left the DNA during the gel purification? Maybe not - the methods don't say that the DNA was purified away from the agarose gel matrix before being analyzed. This step is certainly standard, but if it was omitted then any contaminating arsenic might have been carried over into the elemental analysis.

Re:The Scientific (Publication) Process

[emt377]

Wait, wait, wait. The whole point of publication is to open up your results so that other scientists can poke holes in it and the science can be redone and improved upon. Isn't it kind of a bogus statement say something like "this paper shouldn't have been published"? And with outrage, no less. Could the science really have been that bad and still be approved for publication to begin with? It must have been subject to at least a bit of peer review prior to its release. How come no one was outraged about the guy who reinvented integration (http://science.slashdot.org/story/10/12/06/0416250/Medical-Researcher-Rediscovers-Integration)?!

The paper spurs justified criticism of methodology; that's perfectly reasonable. What ruffles people's feathers is using the resources of NASA to peddle their results in highly hyped press conferences. The lesson here is that if you're going to do that your research better be airtight. And that would include correlating the research by others using different methods. What they have in no way correlates with the presentation, which makes them look like used car salesmen.