New life form discovered, questioned, refuted

There's been much speculation about today's news release by NASA.  Gizmodo has an early report that a new form of life has been found, and that it was discovered on Earth:

At their conference today, NASA scientist Felisa Wolfe Simon will announce that they have found a bacteria whose DNA is completely alien to what we know today. Instead of using phosphorus, the bacteria uses arsenic...

We knew that there were bacteria that processed arsenic, but this bacteria—discovered in the poisonous Mono Lake, California—is actually made of arsenic. The phosphorus is absent from its DNA. The implications of this discovery are enormous to our understanding of life itself and the possibility of finding beings in other planets that don't have to be like planet Earth...

That was December 2.

Update Dec 10:  Since the publication of the study of the arsenic-based organism, a flurry of objections have been raised in the scientific community, several of them summarized in a column at Slate:

None of the scientists I spoke to ruled out the possibility that such weird bacteria might exist. Indeed, some of them were co-authors of a 2007 report for the National Academies of Sciences on alien life that called for research into, among other things, arsenic-based biology. But almost to a person, they felt that the NASA team had failed to take some basic precautions to avoid misleading results...

Some scientists are left wondering why NASA made such a big deal over a paper with so many flaws. "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," says John Roth of UC-Davis.

More at the link for those interested.

Update Dec 11:  Just found this column at The Guardian, with links to multiple sources of discussion of this topic.

Update July 2012:  Original findings thoroughly refuted.