Weird Arsenic-Eating Microbes Discovered? Yes. Finding E.T.? No.

Well, the conference is almost over...and like most of these, not one of the correspondents asks the question(s) that, to me, seem so basic and fundamental.

Firstly, I would have questioned the role and importance of the substitution of arsenic for phosphorus in this particular organism. They obvioulsy tested the viability of the organism in a medium with a high concentration of arsenic, and an absence of phosphorus. So, that certainly implies that the organism can SUBSTITUTE arsenic for phosphorus. But is that due to a fluke mutation in which this particular bacterium has succesfully mutated in response to slowly growing concentrations of arsenic in what is now Mono Lake. Or, is it more fundamental?

In other words, have they taken the same organism and tried to grow it in a medium WITHOUT arsenic, but with suitable levels in phosphorus? Has this particular organism evolved to such an extant that it needs arsenic en lieu of phosphorus...or does it have the capability to "switch" modalities and start using phosphorus if the environment changed.

If this organism cannot re-substitute the classical phosphorus for arsenic in it's nucleic (and other) biotic molecules, then that perhaps implies a much more fundamental difference in this organism then other extant organisms. At the very least, it has diverged from all other forms of known life, to a remarkable level. If, however, it can assimilate phosphorus en lieu of arsenic...then that implies that this organism simply has adapted to an extreme environment, rather then being an example of some fundamentally novel organism.

Actually, the question I have is a slightly different one, which is, can these organisms tolerate an environment with zero phosphorus? The experiments seem to show that they can tolerate high arsenic, and even substitute arsenic for some of the phosphorus in their chemistry-- but is it that they can use arsenic in *addition* to phosphorus, or can they substitute arsenic for *all* of the phosphorus?
Do they still need phosphorus, or can they survive in a completely phosphorus free environment?

This is a fabulous discovery and many of us have burning questions, but I think we're going to have to be patient for a while. Further research will have to be checked and quadruple-checked before they publish the answers.

Hopefully future developments will be available in the "public" media, and not buried away in the expensive subscription-only journals.

I just hope this doesn't open up another silly season in the media. How long will it be before some clueless moron turns this into a Hollywood movie?

Steve

I had an entirely different line of questioning in mind for Felisa:

"How about meeting for dinner, drinks, and fascinating conversation?"

What a *BABE*!! Beautiful, Intelligent, Articulate, Witty, Engaging, etc...
A 10/10 for sure. Wow. You go girl!
:-)

I found this article on the subject to provoke interesting conversations about it:
Everything you need to know about NASA's "completely new form of life"
Read Dr. Steven Brenner's comments near the bottom regarding Arsenic being more useful on Titan than Phosphorus.

Astrobiology has certainly come a long way since the debates over interpreting the Viking results. Eventually think that the success over a more broader consideration of what is considered life may show the fallacy of drawing too great conclusions (as with Viking) from too little data from too few locations looking for too narrow a science product.

We often talk ourselves into thinking of things in an open or shut mindset, when we know too little to justify being so conclusitory.

-nooneofconsequence.

Potential movie title for clueless morons to consider:

"Arsenic and Outer Space"

Yeah, I know -- pretty corny, but not having my coffee yet I couldn't help myself.

This is certainly a nice piece of work, but not, I think, "game changing". I skimmed paper posted to Science Express, .

The organism, strain GFAJ-1, is one member of a family of extremophile bacteria (Halomonadaceae)-- it is definitely NOT "Genesis 2".

The organism grows better using phosphorus than using arsenic; it _can_ grow, and in the Lab _did_ grow, using the standard phosphorus biochemistry in the absence tof arsenic.

GFAJ-1 is truly novel in that it has the ability to incorporate arsenic instead of phosphorus in several key biomolecules including DNA. Arsenic is toxic to all other known organisms because it substitutes for phosphorus. Its bond lengths are different and certain arsenates are much more unstable than the corresponding phosphates so the usual metabolic pathways can't complete.

How GFAJ-1 deals with these differences is a subject of future research. But I think it's safe to say that this is a member of the Halomonadacaea that has _evolved_ an ability to metabolize arsenic: NOT a brand new form of life.

nooneofconsequence, thanks for the link. It is definitely worth the read.

Steve