[meteorite-list] Arsenic Bacteria Hoax

From: JoshuaTreeMuseum <joshuatreemuseum_at_meteoritecentral.com>
Date: Mon, 9 Jul 2012 00:06:11 -0400
Message-ID: <63BF6FFBB51F40319F12E314B7334D5E_at_ET>

Turns out it was a bogus publicity stunt:
http://www.washingtonpost.com/national/health-science/journal-retreats-from-controversial-arsenic-paper/2012/07/08/gJQAFQb7WW_story.html?hpid=z3

Journal retreats from controversial arsenic paper



By Marc Kaufman, Updated: Sunday, July 8, 10:05 PMThe Washington Post
Two new studies of controversial research on a bacterium found in California's
arsenic-rich Mono Lake led the journal Science on Sunday to say that the
2010 paper it published on the microbe was incorrect in some of its major
findings.
The original research, which also had been highlighted by NASA, reported
that the bacterium could live in an environment with very high arsenic and
very low phosphorus - one of the six elements known to be present in all
living things. It consequently raised the possibility of life forms now or
previously on Earth that break what had been accepted as a universal rule of
biology.

But two new studies of the bacterium, GFAJ-1, reported that it could not
grow without the presence of phosphorus. The ?papers also challenged the
original finding that small amounts of arsenic compounds had replaced
phosphorus compounds in some DNA, membranes and other biologically central
parts of the organism.
"Contrary to an original report, the new research clearly shows that the
bacterium, GFAJ-1, cannot substitute arsenic for phosphorus to survive," the
journal concluded in a formal statement.
"The new research shows that GFAJ-1 does not break the long-held rules of
life, contrary to how [lead author Felisa] Wolfe-Simon had interpreted her
group's data."
Nonetheless, Science wrote that it would look with interest at further
research regarding the bacterium, which it called "an extraordinarily
resistant organism that should be of interest for further study,
particularly related to arsenic-tolerance mechanisms."
Wolfe-Simon, now on a NASA fellowship at the Lawrence Berkeley National
Laboratory, is collaborating with senior scientist John A. Tainer on
wide-ranging studies of the bacterium. In an interview Saturday, Wolfe-Simon
and Tainer said that they had produced tentative results in the Berkeley lab
almost identical to the original results at a U.S. Geological Survey
laboratory, and that they were busy finishing the research and preparing
another paper.
Tainer said the two new studies in Science may have come to different
results than theirs because of the methodologies used, the precision used to
detect arsenates and the provenance of the cells. He said the authors of the
two new papers "may well regret some of their statements" in the future.
"There are many reasons not to find things - I don't find my keys some
mornings," he said. "That doesn't mean they don't exist. The absence of a
finding is not definitive."
Wolfe-Simon and her numerous collaborators had made samples of GFAJ-1
broadly available after her initial results caused a storm of controversy,
but she and Tainer said they may have been contaminated or modified in
transit.
She said that all the researchers agreed that the bacterium survived in
extraordinarily high levels of usually toxic arsenic compounds but that they
disagreed about whether the organism used the arsenic compound to grow and
whether it had incorporated the arsenic into its biology.
"I think it's unclear whether this is the last word," ?Wolfe-Simon said.
"They're not finding something that could be there in a minor amount."
One of the new studies in Science was conducted by a team centered at
Princeton University that included Rosemary Redfield of the University of
British Columbia. She was one of the first and most vocal critics of the
original Wolfe-Simon paper, and she said Sunday she was satisfied with how
the process has played out.
"A very flawed paper was published and received an inordinate amount of
publicity," she wrote in an e-mail. "But other researchers responded very
quickly. .?.?. Now refutations of the work by two independent research
groups are appearing in the same high-profile journal, and the refutations
are being well publicized. This is how science is supposed to work."
The new study Redfield was part of did not find any microbial growth when
arsenates were provided to the bacteria without phosphates. Wolfe-Simon had
initially reported that the bacterium grew when phosphorus compounds were
withheld but arsenic compounds were provided. The new study also found no
biologically mediated arsenic in the microbe's DNA, as ?Wolfe?Simon had
reported.
The paper concludes that the bacterium is an extreme life form but one that
has adapted to its environment in a manner similar to many others that live
in conditions long thought to be unsuitable for life.
The second new study in Science came from a research group in Switzerland.
That group also found no growth in the bacteria in a medium with arsenic
compounds but no phosphorus. The paper suggested that Wolfe?Simon's initial
finding may have missed the presence of extremely small amounts of
phosphorus in the arsenic medium, which then allowed the bacterium to grow.
The paper reported that the GFAJ-1 bacteria survived in a culture that had a
ratio of arsenate to phosphate of 10,000 to 1, while other known
arsenic-resistant microbes had ratios that were much lower. As a result,
they concluded, the bacteria was a good candidate for further study.

Phil Whitmer
Joshua Tree Earth & Space Museum










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Received on Mon 09 Jul 2012 12:06:11 AM PDT