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[Strange guy]

We should see if they can swap between phosphorus and arsenic.  Given how similar the two are, I'm not sure being some strange genetic offshoot from long ago is really necessary.

I think I read another article on this (I'll try and find it if anyone's interested) which said that they still have some phosphorus in their DNA and that they grow better in phosphorus rich environments than arsenic, actually preferring it. So more can use arsenic instead rather than arsenic based.

[DJ]

Bad article is bad. Here's a link to a NY Times one. But basically, this isn't a discovery of a new specie, it's scientists training existing bacteria to use arsenic instead of phosphorus.

[LoSboccacc]

Bad article is bad. Here's a link to a NY Times one. But basically, this isn't a discovery of a new specie, it's scientists training existing bacteria to use arsenic instead of phosphorus.

exactly. there is so much hype about this that it makes your head spin. let's do a quick recap:

we're a carbon based life form, not phosphorous based. we use it, we like it, it's quite nice because we can metabolize it easily and it could store a lot of energy in a convenient form (atp).

arsenic is bad, because it works almost like phosphor, so when we ingest arsenic, it gets metabolized in the same way as phosphor and then the metabolic path breaks because it could not do some of the stuff phosphor does, so it clogs down our metabolic system

also, when it get properly metabolized, it's highly unstable, so stuff built with arsenic tend to come apart at the worst time due to the lower binding potential (it's a stretch of what it's happening, let it pass for sake of clarity)

so phosphorous based dna breaks and atp doesn't work right. I don't know if it could be build also in something that resembles phospholipids, but it would be just as bad.

so, what gives? there is this lake, high in arsenic, where bacteria were found. so scientist started to wonder how did they survive, if they can discriminate arsenic and discard it or if they can manage to make arsenic molecules strong enough to be stable, and how

so what they did? take some bacteria, put them in two group, one growing with lot of phosphor and the other with very very low phosphor and high arsenic.

then they took the arsenic surviving bacteria and compared it to the others. they were found to indeed contain arsenic based molecules, and they found that those molecules went as far as being in their dna. they found that arsenic grown cells were bigger, but is still uncertain to how this helps to maintain arsenic molecules stable.

those are stil carbon based life form, and not of any different kind from what we know about life. they have the same basic metabolism, they works using the same dna we found in almost every other lifeform, and they're not arsenic based.

[Muz]

I'm not surprised. I sort of expected this kind of thing.. people are too quick to assume that just because they haven't found something, it isn't possible. But I don't understand any of this chemical science stuff, so I'll just automatically assume that it's cool.

[Urist Imiknorris]

http://xkcd.com/829/

[nordak]

Mars would have had lifeforms similar to earth's based on its composition.

[RedWarrior0]

http://xkcd.com/829/

Beat me to the punch.

[Heliogabalus]

better article maybe
http://www.nature.com/news/2010/101202/full/news.2010.645.html

as a biochemist, sort of, this stuff is a lot more interesting than if they had discovered some spectral lines of an organic chemical in the atmosphere of wherever.

The article states the culture grew in low phosphate/high arsenic and not in low phosphate, making new DNA with arsenic, that's pretty neat, gotto wonder if the geometry is the same etc.
But what really makes it cool is replacing adenosine triphosphate (ATP) with adenosine triarsenate (ATA or whatever it will be called) really makes you wonder how much energy there is in ATA compared to ATP.  So actually, on a very basic level the metabolism is completely changed. ATP is the main carrier of energy in the cell, carrying energy from reactions where material is broken down, to reactions where structures are synthesized. That'll also really change a lot of stuff when you're doing your enzyme kinetics is what I'm saying. Exciting!

[Sheb]

As I'm excited as you do (I'm a biochemist-in-training :p) but they didn't prove arsenate was in the adenosine tri-whatever. They did found a lot of arsenate in part where you'd expect phosphorus, but it could be that arsenate is used in DNA and the trace of phosphorus could be use for ATP. Of course, you just need to continue growing your bacteria in an arsenate-only environment and the trace will eventually get out.

But yeah, it's goddamn exciting! It just sucks that I cannot talk to my teachers about that until tuesday.

[cerapa]

Im just wondering, if you were to eat aliens that used arsenic like that, would you be poisoned?

[Criptfeind]

Im just wondering, if you were to eat aliens that used arsenic like that, would you be poisoned?

I don't know if there would be enough Arsenic. DNA is really small and I don't know the sugar to Arsenic ratio.

[Mysteriousbluepuppet]

Wasn't there a big todo about the theory of silica based lifeforms, and the scientific community rejecting it since silica wasn't one of the building blocks?

I mean, if arsenic can be incorporated into DNA, then it stands to reason almost any configuration is possible.

Not the same thing, carbon use is its ability to do lidicrusly long  chain that remain stable ( think hundreds). Silica could only get about 20, and that require huge pressure and heat. It would be dead from hypothermia in a volcano

[Virex]

Make that hundredth thousands if you want to. Living radical polymerization and especially metallocene-based Ziegler-Natta polymerization can yield pretty sick high chain lengths. Biologicial polymers can probably be a lot longer still (take DNA for example).

But what really makes it cool is replacing adenosine triphosphate (ATP) with adenosine triarsenate (ATA or whatever it will be called) really makes you wonder how much energy there is in ATA compared to ATP.  So actually, on a very basic level the metabolism is completely changed. ATP is the main carrier of energy in the cell, carrying energy from reactions where material is broken down, to reactions where structures are synthesized. That'll also really change a lot of stuff when you're doing your enzyme kinetics is what I'm saying. Exciting!

Bond energies for Arsenic compounds are usually lower then for phosphorus compounds (arsenic is bigger and heavier), so ATA would probably store less energy then ATP.

[Sowelu]

Thank you for showing up Virex!  Having an expert is good.

[Criptfeind]

But what really makes it cool is replacing adenosine triphosphate (ATP) with adenosine triarsenate (ATA or whatever it will be called) really makes you wonder how much energy there is in ATA compared to ATP.  So actually, on a very basic level the metabolism is completely changed. ATP is the main carrier of energy in the cell, carrying energy from reactions where material is broken down, to reactions where structures are synthesized. That'll also really change a lot of stuff when you're doing your enzyme kinetics is what I'm saying. Exciting!

Bond energies for Arsenic compounds are usually lower then for phosphorus compounds (arsenic is bigger and heavier), so ATA would probably store less energy then ATP.

Anyone thinking what I am? Nitrogen time!