f13.net

Looks like we got our aliens...

http://gizmodo.com/5704158/

Ok, so alien in form rather than green martians, but still interesting. NASA discovered microbes on earth which uses arsenic instead of phosphorous as a basic building block, right down to the DNA level.

That's kind of a big deal.

How is it a big deal?  It would seem to me that what we know as the basic building blocks of life (oxygen, water, phosphates, whatever) wouldn't necessarily be the basic building blocks of life for stuff on other planets/systems.  I figured that sort of assumption would be a given, and not exactly earth shattering zomg call a press conference news.  I get that it's a big deal here, but on planet Zoltron 451b?  Not so much.

Because it's about diversity.

This is yet another 'What, Really ?' that the universe has thrown at us.

It's awesome.

Press release (http://www.nasa.gov/topics/universe/features/astrobiology_toxic_chemical.html)

The suggestions seems to be that this microbe can substitute arsenic in place of phosphorous within metabolism. If this is what they are implying then this is pretty remarkable, and just goes to show how phenomenal life is. The dominance of phosphorous in metabolism has been presumed to be ubiquitous across the spectrum of life. This discovery adds weight to the notion that there are other forms of life which can exist and thrive.

Whoops, I merged the topics and it ate yours. Sorry, K9.

I think it's awesome. My roommate said "Was this even worth a press conference?". Made me want to punch him. "It's no iphone 4..."

It's a big deal because, despite everyone assuming this was the case, we didn't previously have proof of it. 

No worries

For those with access here's the relevant paper in Science. (http://www.sciencemag.org/content/early/2010/12/01/science.1197258)

There is still a lot of uncertainty surrounding the findings, but this has the potential to to be big. I do love it when the microbial world turns up yet another awesome way of living that had previously been assumed to be impossible, it really makes you see how narrow old or existing assumptions of what life is are.

Thanks K9!

One of the points brought up in the press release was that replacements could make life more feasible in extreme environments. Though arsenic is apparently a very unstable replacement for phosphorous at room temperature, in cold extremes it could make more sense.

It's about proof of the possibility, rather than just idle speculation. Theoretical Biology is a wonderful field, but there is a line between theory and fantasy; discoveries like this allow us to bulk out the theory side of our understanding, while allowing us a tad more certainty in our fantasy. It also reinforces that "extremely improbable" is not a disqualifying point and nature generally will find a way.

On a side note, related; so much of these interesting organisms have only been discovered in the last few years; thanks to the advent of better genome sequencing methods. The majority of microbial species cannot be cultured (grown) outside of their natural environment and as such most cannot be studied, or could not. High resolution genome sequencers permit the study of microbes culture-free though, and the stuff we are finding is nothing short of remarkable. One of my favourites is a bacterium called Deinococcus radiodurans (http://en.wikipedia.org/wiki/Deinococcus_radiodurans); this species can handle over 15,000 Gy of radiation (5Gy would be enough to kill you) and can subsequently reassemble its entire genome in a matter of hours.

This is amazing, really. Wish I had the depth of knowledge to truly appreciate it.

Being made of arsenic seems like a fantastic way to discourage predation by non-arsenic lifeforms.   :why_so_serious:

Ok now then, the $10 billion question: How do we use this to defeat terrorism?  :why_so_serious:

Cool stuff in all seriousness though. Life finds a way.

Indeed.  That was my first thought.  And then my next thought was 'holy fuck, I bet the beastie that evolved so it COULD is a bad bastard.'  Of course, when we find the bad bastards, we'll probably call them Species 91 or Homonid 832 instead of something cool like 'Shaft'.

The possibility that the organism can replace phosphorous with arsenic IN THE DNA CHAIN is just beyond bizarre.  I can see why there are those calling bullshit on this.  If true it's just... wow.

Why would they lie about it?  It's now published in Science.  It would be a quick way to end one's career.

To be fair, they're not sure that As has replaced P in DNA, ATP, etc. it's just all the analysis they've done significantly indicates it has  :awesome_for_real:

Well, they might just be wrong; I doubt they are wilfully making stuff up.

That's science for you.  You're right, right up until some other guy proves you wrong.

I heard the Earth was flat once.

In fairness that probably wasn't until the 19th Century when crazy people decided the bible was literal in the most simplistic way possible. The Ancient Greeks were totally in favour of globes, although they though the idea of anyone living on the lower half was pretty crazy.

My lab is so proud of themselves for having a hand in this.  It's amusing to see how much in the news stuff they've had lately.

OMG!  We know someone related to this.  Can I have your autograph?

:Love_Letters:

Except they fudged the figures by a factor of 10 because the world couldn't POSSIBLY be that big.

Apparently the name of the bacterium (GFAJ-1) stands for "Get Felisa a Job" after the first author of the paper  :grin:

This.  If my reading of the article was correct, they aren't sure, but given the results they saw it seemed like it was a possibility (so they speculated that is what happened). 

I wasn't saying they were lying, I was just finding it hard to believe that an organism could fundamentally change the structure of the machinery that builds all the parts the organism needs to exist.  If it's true it's really, really weird.

Someone going "Hmm, that's weird" is where most of the good science comes from, though.

A commentary from a chemist's perspective (http://pipeline.corante.com/archives/2010/12/02/life_with_arsenic_whod_have_thought.php)

Short and readable, and the comments section is astonishingly readable too.

They raise some interesting thoughts about alternative substitutions: silicon for carbon, arsenic for phosphorous, selenium for sulphur.

Standard last words uttered as well.  :why_so_serious:

Sounds like the recipe for a xenomorph right there.

Silicon-based life has been speculated about for quite some time and has been a staple of science fiction as well (e.g. the Horta in Star Trek).

Old Dr. Who, Masters of Orion, etc.

We're still trying to get even a basic understanding of the proteins we know.  Despite knowing an impressive amount, we actually know very little of the full picture and exactly how proteins work.

There was a really interesting paper about six months back which estimated that earthbound life has only explored a tiny percentage of possible protein space; so the potential for entirely novel lifeforms and biomolecules is vast.

There are some pretty good reasons why Arsenic, Silicon, Selenium and similar are not the norm; even in this case the organisms prefer to use phosphorous when it is available. What's interesting is how these organisms can adapt to survive under starvation conditions.

(http://imgs.xkcd.com/comics/arsenic_based_life.png)

Because it proves what you assumed was a given, but couldn't prove? That's kind of what scientific discoveries are all about.

This is great stuff and v. interesting but the highlight for me is that the fact that you have a favourite bacterium.

Working on bacterial evolutionary dynamics does that to you  :awesome_for_real:

Since I don't think it's been said yet, I welcome our new, arsenic-based overlords.

That meme quit being funny over 9000 years ago.

You mom quit being funny nine minutes ago.

Fixed

Fixed.

Seriously, you don't have to be a major bio-chem geek to understand why this is awesome.  Arsenic is poisonous because it's close enough chemically to phosphorus to get sucked up by the same biochemistry, but doesn't quite work.  That this bug is using it interchangeably is huge.  Imagine a step further, a cellular chemistry that not only used them interchangeably, but used the the alternation of them to encode information.  Effectively you'd have added another layer of coding to the DNA.

If it can be this different, it can be almost unimaginably different.  Any complex chemical chain could potentially serve as the basis for "life".

--Dave

...and have acid for blood!  :drill:

Timothy Leary didn't qualify?

There are complaints from other scientists that the experiment was sloppy (http://www.slate.com/id/2276919/pagenum/all/).

Article is from Slate, but I had read another piece last week that sited a different biologist complaining about how sloppy the experiment was run.  It's getting to be a mantra on f13, but amazing claims require amazing evidence (yes, I realize that isn't the exact quote).

It's written by Carl Zimmer and had been done pretty well. I have to agree that the initial suggestions aren't looking so well backed up now. I suspect more good things will come out of this in time, but this paper will now endure as one which was over hyped I suspect.