## Monday, July 09, 2012

### Two papers: no bacteria use As to grow

At the beginning of December 2010, I was excited by claims by Ms Iron-Lisa Wolfe-Simon that she had found bacteria that used arsenic instead of phosphorus to grow. Note that phosphorus is one of the five main elements for life.

Within days, however, I was persuaded by various criticisms and at the end of December 2010, I was already firmly in the camp of skeptics.

On Sunday, two papers were published in Science. They claim that the authors have verified that while the bacteria can indeed tolerate arsenic remarkably well, they don't use it to grow.

Felisa apparently plans to defend the validity of her famous paper. She said the following:
There is nothing in the data of these new papers that contradicts our published data.
This wording of her defense suggests that she wants to play some games that are not entirely clean. Why doesn't she clearly articulate whether she accepts that it's been proved that arsenic can't be incorporated into the new cells?

The conclusions of the papers, Felisa's paper and the new ones, clearly contradict each other so someone has to be wrong here. I realize that she played different games at different places but at least at some places, she has surely claimed that arsenic was being used in an essential way for the microorganisms to live. That's where her fame really came from.

So just to be sure, I will be among those who would not accept her hypothetical claim that she has never claimed that arsenic replaces phosphorus in some wonderful organisms. She has done so whether or not she can cherry-pick a subset of her proclamations or papers where this statement is absent.

Just to be sure, I am not 100.000% certain that she's been wrong but it seems likely that the probability will be converging towards 100% in coming days or weeks or months.