Oleg Zabluda's blog
Tuesday, July 10, 2012
 
In a 2010 Science journal publication, NASA Ames Research Center astrobiologist Felisa Wolfe-Simon (now at LLNL)...
In a 2010 Science journal publication, NASA Ames Research Center astrobiologist Felisa Wolfe-Simon (now at LLNL) with big fanfare claimed that bacterium GFAJ-1 from alkaline Mono Lake, is capable of substituting arsenic (As) for a small percentage of its phosphorus (P) and grow. Then it was debunked.

Mono Lake is our stomping grounds. NASA Ames is "our" NASA research center. And astrobiology is my hobby. Let's see what happened and stuff.

Arsenic is chemically very close to P (right below it in the Periodic Table), so it easily gets incorporated instead of P into living organisms, but not so close as to actually work, that the reason it's so extremely toxic. Felisa grew the bacteria in the As environment "devoid of P", and observed growth. The erroneous results were most likely the due to trace contamination with P. Felissa stands by her results.

Still, GFAJ-1 bacteria is the current record-holder for As-resistance and tolerance for low-levels of P, but it did not substitute As for P.

Main structure (and DNA) of living organisms are made out of H,C,N,O,P.S. Water is not a part of the structure. It would be totally awesome to find any substitution. For example

H->Li
C->Si
N->P
O->S
P->As
S->Se
 
Any of that would be a huge deal, tremendously widening our known range of life. Too bad it didn't pan out, and after such a hype.

There was also an funny anecdote about how her husband was getting increasingly disturbed about her studying arsenic biochemistry, before she told him what she was working on. Classic.

You know who has no shortage of Phosphorus? The Hound of the Baskervilles!

http://en.wikipedia.org/wiki/GFAJ-1
http://en.wikipedia.org/wiki/Mono_Lake
http://en.wikipedia.org/wiki/Ames_Research_Center
http://en.wikipedia.org/wiki/GFAJ-1

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