NASA Finds New Life (This Afternoon)

While the official 2pm conference should have more answers, most of the internet has decided that NASA has discovered a completely new life form based on arsenic instead of the more traditional organic materials. We'll know more in a few hours.

It's the Shadow Biosphere Lake

[eldavojohn]

Mono Lake was mentioned back in 2009 [slashdot.org] and in March [slashdot.org] as potentially harboring this 'shadow biosphere.' Felisa Wolfe-Simon, the geobiologist credited with this [ironlisa.com] (Iron Lisa = Felisa, get it?) led me to an interesting PDF [ironlisa.com] that begins:

If you were asked to speculate about the form extra-terrestrial life on Mars might take, which geomicrobial phenomenon might you select as a model system, assuming that life on Mars would be 'primitive'? Give your reasons.

At the end of my senior year at Rensselaer Polytechnic Institute in 1968, I took Professor Ehrlich’s final for his Geomicrobiology course. The above question beckoned to me like the Sirens to Odysseus, for if I answered, it would take so much time and thought that I would never get around to the exam’s other essay questions and consequently, would be "shipwrecked" by flunking the course. So, I passed it up.With this 41-year perspective in mind, this manuscript is now submitted to Professor Ehrlich for (belated) "extra-credit." R.S. Oremland

This has been an interesting topic in sci-fi [wikipedia.org], I recall an X-Files that revolved around silicon based life.

I certainly hope that we get more details than this teaser (all other news articles seem to point back to Gizmodo). From the sound of this leak I can't tell if the DNA itself is foreign or if it's made of the same Adenine, Thymine, Guanine and Cytosine with similar hydrogen bonds or if the DNA is similar but different in functionality or if it doesn't create proteins and RNA the same way or if phosphorus component is just switched with arsenic (two very similar elements prebiotic chemically) or if the whole bacteria is made of arsenic. At what point in the chain of DNA to organism does this thing seriously differ? The Gizmodo article is painfully weak on detail.

Re:It's the Shadow Biosphere Lake

[Halo1]

According to an article by the official Flemish news service [deredactie.be], the beans were already spilled this afternoon in a documentary shown by a Dutch broadcast service (VPRO) on this topic. It's indeed about Mono lake and Felisa Wolfe-Simon. The article also contains a small film fragment in which they confirms that it's indeed about a life form that uses arsenic instead of phosphor (it also contains some sound bytes from the researcher, in English).

Re:Just wondering....

[Mindcontrolled]

Is carbon a deadly posion for an arsenic-based life form?

Such an arsenic-"based" life form would still be made up mostly of carbon, the arsenic would replace phosphor instead. So, carbon would be most likely harmless to them while phosphor might indeed be toxic, in a reversal of the toxicity mechanism of arsenic, which works, among other mechanisms, by replacing the phosphate groups in adenosine triphosphate.

The really interesting question is how an arsenic-based bacterium would avoid the effect of arsenic binding to sulfhydryl groups in proteins.

Re:Why this is important

[Anonymous Coward]

All life on Earth that we know of is related. It all uses the same basic DNA/RNA mechanisms (including the same four base pairs), uses the same specific molecules that prominently feature carbon as the basic assembly blocks of the cell, etc.

Hate to bring you down, but from everything I hear, the life isn't "arsenic-based" in the same sense that we're "carbon-based". Instead, all indications are that it's "simply" arsenic replacing phosphorus in the DNA backbone.

As a biochemist, I can almost assure you that the rest of the DNA looks the same. That is, these organisms have the same A/T/C/G DNA bases. I'd guess the (deoxy)ribose sugar part of the sugar-phosphate backbone is the same. It's just the phosphorus in the phosphate has been replaced by the chemically similar arsenic. Anything more extensive would be the selling point, and arsenic would be a secondary (but still important) consideration.

This means that biogenesis only happened once. You aren't going to convergent evolve A/T/G/C with a (deoxy)ribo-chalconide backbone. (That's why they would be the bigger news items.) Instead, what probably happened is that the bacteria started out using phosphorus, and then the enzymes which use phosphorus got "sloppy" and started to use arsenic compounds instead. Since there was more arsenic than phosphorus where they were living, they gradually evolved to use arsenic instead of phosphorus.

Really, really cool. Mind-blowingly awesome, in fact. But not evidence for a seperate abiogeneis, unfortunately.

Re:It's the Shadow Biosphere Lake

[BJ_Covert_Action]

Hey, just wanted to weigh in before you ruin your own vacation this spring. I grew up in Tuolumne County, California, just west of the Mono Lake area (in fact, we have a few historical sites dedicated to Mark Twain in that area). The foothills of the Sierra Nevada were my playground and Yosemite is nothing more than a tourist trap to us locals. If you are going to head up to Mono Lake or the nearby Bridgeport Reservoir or Grant Lake for vacation, don't go in the spring. The snowpack will last well into May and you will freeze your tucus off if you decide to go swimming in any of those mountain lakes that early (essentially you would just be swimming in melted snow...and it really is frackin' cold). If you really want to check out that location, especially for lake activities, I suggest waiting until very late July or, even better August. The drive up there will be hot as all balls, but the lakes will be much more temperate and kind to splash around in.

Just do us a favor and be careful with your campfires and such that time of year. A lot of us get tired of having half our damn county burn down every summer because of tourists being careless with cigarette butts and such. Dry grass burns fast. Just remember that and you should have a dandy vacation. Enjoy the Sierra Nevada when you get here. =)

Arsenic and old earth / Washington Post

[Doofus]

The Washington Post has a story on the finding, Second Genesis on Earth? [washingtonpost.com]

quoting:

But now researchers have uncovered a bacterium that has five of those essential elements but has, in effect, replaced phosphorus with its look-alike but toxic cousin, arsenic.

News of the discovery caused a scientific commotion, including calls to NASA from the White House and Congress asking if a second line of Earthly life has been found.

A NASA press conference Thursday and an accompanying article in the journal Science, gave the answer: No, the discovery does not prove the existence of a so-called "second genesis" on Earth. But the discovery very much opens the door to that possibility, and to the related existence of a theorized "shadow biosphere" on Earth--life evolved from a different common ancestor than all that we've known so far.

Re:How much you ask

[Cytotoxic]

It is bigger than that. Firstly, arsenic is more reactive and as such the backbone of the DNA would be very unstable. That's a huge problem - how did this organism solve it? That could be a second Nobel prize right there.

Also, although adenosine will bind arsenate to make an arsenic based AMP analog (AMA?), it is the final phosphate from ATP that gets bound in the backbone. You have to have lots of machinery altered to get ATP built with arsenate on the terminus and transport that arsenate enzymaticly into the growing DNA chain. It's been about 25 years since I did biochemistry, but there's about a hundred "holy crap" things about this discovery. Each of those little pieces of the discovery will get you the cover of Science or Nature if you unlock it. Really, this is a super-cool finding. Short of putting ET on the dais I don't know what would be more shocking.