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NASA discovers new lifeform with totally different DNA than anything else

by Simfish
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Simfish
#1
Dec2-10, 12:53 PM
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http://gizmodo.com/5704158/nasa-finds-new-life

This might EASILY be the most amazing discovery in several decades, if not a century.

Seriously, could anyone's theory have anticipated this discovery?

EDIT: Okay it might not be independently evolved from other lifeforms (gizmodo article was too sensationalist). But it's still amazing
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Ygggdrasil
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Dec2-10, 01:06 PM
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There is reason to doubt that the organisms' DNA really does contain arsenic instead of phosphorus:

[Astrobiologist Steven Benner] was impressed by the finding that bacteria could get by with so little phosphorus and so much arsenic, but he questioned the conclusion that the arsenic was truly taking the place of phosphorus. Benner explained that chemists have long been familiar with the properties of arsenate compounds. "We know, for example, that they fall apart in water quickly," he said. "Those structures are not going to survive in water."

In their paper, Wolfe-Simon and her colleagues say that the GFAJ-1 bacteria can apparently cope with that instability, perhaps because of intracellular mechanisms that keep water out. Benner, however, said that other scientists would have to first confirm that the arsenic is really being taken up the way the paper describes, and then figure out how the process squares with what's already known about biochemistry.

"If this result is true, we've got to go back and rewrite a lot of chemistry," Benner said.

Benner is willing to put his money where his mouth is: "I've wagered Felisa $100 that that's not arseno-DNA," he told me.
(http://cosmiclog.msnbc.msn.com/_news...ow-it-on-earth)

By labeling the arsenic with radioactivity, the researchers were able to conclude that arsenic atoms had taken up position in the microbe’s DNA as well as in other molecules within it. [Biochemist Gerald Joyce], however, said that the experimenters had yet to provide a “smoking gun” that there was arsenic in the backbone of working DNA.

Despite this taste for arsenic, the authors also reported, the GFAJ-1 strain grew considerably better when provided with phosphorus, so in some ways they still prefer a phosphorus diet. Dr. Joyce, from his reading of the paper, concurred, pointing out that there was still some phosphorus in the bacterium even after all its force-feeding with arsenic. He described it as “clinging to every last phosphate molecule, and really living on the edge.”
(https://www.nytimes.com/2010/12/03/s...03arsenic.html)

I'll reserve judgment until I've had time to fully read the study.
berkeman
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Dec2-10, 01:07 PM
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http://www.nasa.gov/multimedia/nasatv/index.html

On NASA TV now...

FlexGunship
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Dec2-10, 01:11 PM
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NASA discovers new lifeform with totally different DNA than anything else

Quote Quote by Simfish View Post
http://gizmodo.com/5704158/nasa-finds-new-life
This might EASILY be the most amazing discovery in several decades, if not a century.
Seriously, could anyone's theory have anticipated this discovery?
Either way, I welcome our new arsenic-loving overlords.

EDIT: http://www.nasa.gov/topics/universe/..._chemical.html (written release)
Monique
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Dec2-10, 01:13 PM
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Actually its DNA normally contains phosphor, the discovery is that it can use arsenic when it doesn't have a source of phosphor. Very remarkable and important discovery, but I would not call it a new life form.
FlexGunship
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Dec2-10, 01:16 PM
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Quote Quote by Monique View Post
Actually its DNA normally contains phosphor, the discovery is that it can use arsenic when it doesn't have a source of phosphor. Very remarkable and important discovery, but I would not call it a new life form.
I've been known to use a little arsenic from time to time in my cooking. Wait... no... what's that called? Umm... allspice!
leroyjenkens
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Dec2-10, 01:59 PM
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Quote Quote by Monique View Post
Actually its DNA normally contains phosphor, the discovery is that it can use arsenic when it doesn't have a source of phosphor. Very remarkable and important discovery, but I would not call it a new life form.
So it has the ability, in an environment lacking phosphorus, to instead use arsenic in the DNA? Can their DNA contain arsenic completely as a 100% substitute for phosphorus?
jobyts
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Dec2-10, 02:09 PM
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A comment someone posted on some website:
"Now, if we could make bacteria that utilize germanium (two periods down from carbon) and arsenic, we'd have living semiconductors...think of it...somewhere in the universe Ge/As bacteria may have evolved into a transistor radio that plays "Duke of Earl"."
_Tully
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Dec2-10, 02:14 PM
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Is the actual study released yet?

Anticlimactic so far, I have to admit.
hypatia
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Dec2-10, 02:15 PM
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Quote Quote by FlexGunship View Post
Either way, I welcome our new arsenic-loving overlords.
Ahahhaha, love it.
FlexGunship
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Dec2-10, 02:17 PM
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Quote Quote by hypatia View Post
Ahahhaha, love it.
No more Trekkie-style alien lovefests though. One kiss and you've got a mouthful of arsenic.
waht
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Dec2-10, 02:18 PM
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Arsenic life always welcomed.
Monique
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Dec2-10, 02:22 PM
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What I wonder is what the bacterium does instead of phosphorylation, in the absence of phosphor. Arsenicylation?
Monique
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Dec2-10, 02:53 PM
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The original study: http://www.sciencemag.org/content/ea...cience.1197258
Life is mostly composed of the elements carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. Although these six elements make up nucleic acids, proteins, and lipids and thus the bulk of living matter, it is theoretically possible that some other elements in the periodic table could serve the same functions. Here, we describe a bacterium, strain GFAJ-1 of the Halomonadaceae, isolated from Mono Lake, California, which substitutes arsenic for phosphorus to sustain its growth. Our data show evidence for arsenate in macromolecules that normally contain phosphate, most notably nucleic acids and proteins. Exchange of one of the major bioelements may have profound evolutionary and geochemical significance.
bobze
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Dec2-10, 04:05 PM
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Quote Quote by _Tully View Post
Is the actual study released yet?

Anticlimactic so far, I have to admit.
Yes, its up at sciencemag.org. Just finished reading it and I have to say, I'm not sure why I let myself buy into all the "media hype". As these things normally are, it was over-sensationalized.

The whole reason that arsenic is poisonous is because it is so chemically similar to phosphorous that our enzymes and biochemical pathways can't tell it apart. That an organism evolved the ability to cope with this hurdle under an environment of reduced phosphates and prevalent arsenates is pretty unremarkable considering how clever evolution can be. Certainly no less remarkable that vertebrates that don't use "blood", archaea that thrive in radioactive waste or boiling sulfuric acid or invertebrates that enjoy life at a cozy 176 F and 250+ atms.

Probably the coolest implication from this discovery in my opinion, comes for origins of life research specifically for making nucleotides composed of a nucleoside and arsenate instead of nucleoside and phosphate. The upside to this, is that the reaction (nucleotide formation) happens much more rapid with arsenates and nucleosides (minutes) so could have possibly been the first use of nucleic acid material prior to more complex life.
madcat8000
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Dec2-10, 04:30 PM
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Are the implications that it uses arsenic in every way the same as it uses phosphorus or only in certain select aplications? Do they use Adenotriarsenate instead of Adenotriphosphate? IMHO if it only uses arsenic where its convienient and easy then its a cute biochemical trick, but if it uses ATAs......thats a real biochemical revolution!!!
bobze
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Dec2-10, 04:34 PM
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Quote Quote by madcat8000 View Post
Are the implications that it uses arsenic in every way the same as it uses phosphorus or only in certain select aplications? Do they use Adenotriarsenate instead of Adenotriphosphate? IMHO if it only uses arsenic where its convienient and easy then its a cute biochemical trick, but if it uses ATAs......thats a real biochemical revolution!!!
Right now, they aren't entirely sure. They found that arsenate was present in in the correct ratios that phosphates were to suggest it used them in DNA as well as protein and some lipid.

So yes, they are suggesting that they form nucleoside (adenosine, guanosine, thymidine, cytidine and uridine) mono/di/triarsenates. But we await further confirmation.

As I pointed out earlier, that wouldn't be so surprising because arsenates cause toxicity by your enzymes choosing them and will do this "naturally" because to them arsenate and phosphate is essentially identical. Which is unfortunately why arsenate poisons us lesser beings :)
Huzzah
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Dec2-10, 04:44 PM
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Quote Quote by jobyts View Post
A comment someone posted on some website:
"Now, if we could make bacteria that utilize germanium (two periods down from carbon) and arsenic, we'd have living semiconductors...think of it...somewhere in the universe Ge/As bacteria may have evolved into a transistor radio that plays "Duke of Earl"."
So, if you submerged bacteria in water (With aqueous germanium or silicon) with no source of carbon at all, would this eventually happen to the bacteria?


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