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As Mono Lake is of volcanic origin and formed around 760,000 years ago (per Wikipedia) I'd be astonished if the arsenophile(?) evolved there in that short a tim

by cstross 16y ago

As Mono Lake is of volcanic origin and formed around 760,000 years ago (per Wikipedia) I'd be astonished if the arsenophile(?) evolved there in that short a time span. Which leaves open the question of where it came from, and whether arsenic tolerance is present but dormant in other extremophiles. Other points of note: never mind the cellular DNA integrating arsenate, the whole respiration cycle seems to be affected, presumably running on ATA rather than ATP. Which implies huge amounts of molecular booty in the shape of enzymes that are powered by a different reduction gradient (ATA-AMA rather than ATP-AMP). Possible down to earth applications? Lest we forget, Pakistan has a monstrous problem with arsenic-contaminated wells ( http://www.irc.nl/page/16331 http://www.irc.nl/page/16331 ) and a bacterial culture that thrives on arsenic could offer new approaches to arsenic sequestration. And that's just off the top of my head. (My biochemistry is, alas, too rusty to go much further without a refresher course. Hmm ...)

jacquesm 16y ago
If a bacterium consumes the arsenic from a contaminated well the well is now contaminated with the corpses of bacteria that are rich in arsenic. You'd have to add another pass to get rid of the bacterial residue (possibly easier, but still).
- enjo 16y ago
  Doesn't that depend on the byproduct produced by the respiration cycle?
  - jacquesm 16y ago
    Apparently they accumulate it.
- sudont 16y ago
  Possibly a small sludge pond that would filter the water through as per a sewage treatment plant? I'm thinking that if it's in the wells, it's due to the solvent action of water on the rocks, and cleaning out the wells would only be a temporary solution.
  - cstross 16y ago
    Currently AIUI they use ion exchange resins as filters. Which is okay, but they run out eventually. A sludge pond might well be a better solution (although that's best left to an environmental engineer -- do we have any on HN)?
- lukeschlather 16y ago
  Clearly, the bacteria aren't going to magically destroy the arsenic. But eat the arsenic, die and float to the surface of the well where they can be skimmed off? I'd say that's a simple goal for some genetic engineers to start gunning for. It's also plausible they could metabolize it into some non-toxic form. (We've got a variety of biomolecules we've never seen before, some of which could be non-toxic.)
- InclinedPlane 16y ago
  Arsenic is this big: (makes gesture with thumb and forefinger a few angstroms apart), bacteria are this big: (makes gesture with thumb and forefinger a few microns apart). OK, that's not overly helpful, the point being, you can filter bacteria out of water a whole hell of a lot easier than you can filter out dissolved arsenic.
  - niels_olson 16y ago
    Couple of thoughts: 1) precipitating arsenic salts directly might be easier and a whole hell of a lot easier to provably run to completion. 2) to filter out bacteria, you'd have to grow bacteria. In addition to arsenic, you'd also have to add sugar and protein. Last I checked, Islam take a pretty hard line on beer.
    - freiheit 16y ago
      However, beer is made with yeast, not bacteria. And from what I can tell, most reasonable forms of Islam interpret the beer thing as forbidding intoxication. I don't think any forbid bread (solid beer), for instance. Yogurt and pickles are also made with bacterial processes and I don't think they're forbidden in Islam.
dotBen 16y ago
Back in the discussion thread pre-announcement a few days back, I mentioned Mono Lake as potentially being a source for this (http://news.ycombinator.com/item?id=1953749 http://news.ycombinator.com/item?id=1953749 and http://news.ycombinator.com/item?id=1953756 http://news.ycombinator.com/item?id=1953756). I just wanted to reiterate my suggestion for any bio-geeks living in the Bay Area - Mono Lake is only 2hrs drive from Bay Area and it is FASCINATING. I would really encourage anyone who is interested in ecology and biochemistry to go check it out if you are passing through to Mammouth Lakes for snowboarding or taking a trip to Yosemite which is next door.
hyperbovine 16y ago
Do you have any basis for the claim the 760k years would not be enough time for such a feature to arise? After all, some surprisingly complicated things (http://en.wikipedia.org/wiki/Evolution_of_the_eye http://en.wikipedia.org/wiki/Evolution_of_the_eye) are believed to have evolved (more than once) over shorter periods.
- philwelch 16y ago
  Number of years is mathematically irrelevant. Number of generations is mathematically relevant. Bacteria produce new generations prodigiously. Consider: antibiotics were invented less than a century ago, and bacteria have already evolved a resistance to penicillin. That's probably more than humans have evolved for 100,000 years. 100 years is like five generations for humans, but billions of generations for a bacteria. 760,000 years? That's tons of time for bacteria. Especially since bacteria are pretty simple; more complicated life has a much harder time evolving.
  - Jabbles 16y ago
    Assuming bacteria reproduce once per day, a century would be ~30000 generations. Not billions. 760,000 years ~ 3e8 days, whether that is "tons of time" I can't comment.
    - philwelch 16y ago
      Assuming bacteria reproduce once per day I think that's an underestimate, by at least an order of magnitude.
dnautics 16y ago
"I'd be astonished if the arsenophile(?) evolved there in that short a time span" Why not? http://en.wikipedia.org/wiki/Berkeley_Pit#Extremophiles http://en.wikipedia.org/wiki/Berkeley_Pit#Extremophiles BTW, the ATP-AMP reaction is not a electrochemical reduction reaction, it's rather the mundane hydrolysis of a phosphodiester bond. We don't know what the energy potential of an arsenodiester bond is (although some speculation is that it carries a bit less energy).
cKeyser 16y ago
I'd use the word arsenotolerant instead. The cells still preferentially utilize phosphorous when given the option. The prefix phile generally implies that they require such conditions to live, like a thermophile isn't viable at a temperature below (roughly) 40 C. This organism would have no trouble growing in the absence of Arsenic. =)

by cstross 16y ago

jacquesm 16y ago

If a bacterium consumes the arsenic from a contaminated well the well is now contaminated with the corpses of bacteria that are rich in arsenic. You'd have to add another pass to get rid of the bacterial residue (possibly easier, but still).

enjo 16y ago
Doesn't that depend on the byproduct produced by the respiration cycle?
- jacquesm 16y ago
  Apparently they accumulate it.
sudont 16y ago
Possibly a small sludge pond that would filter the water through as per a sewage treatment plant? I'm thinking that if it's in the wells, it's due to the solvent action of water on the rocks, and cleaning out the wells would only be a temporary solution.
- cstross 16y ago
  Currently AIUI they use ion exchange resins as filters. Which is okay, but they run out eventually. A sludge pond might well be a better solution (although that's best left to an environmental engineer -- do we have any on HN)?
lukeschlather 16y ago
Clearly, the bacteria aren't going to magically destroy the arsenic. But eat the arsenic, die and float to the surface of the well where they can be skimmed off? I'd say that's a simple goal for some genetic engineers to start gunning for. It's also plausible they could metabolize it into some non-toxic form. (We've got a variety of biomolecules we've never seen before, some of which could be non-toxic.)
InclinedPlane 16y ago
Arsenic is this big: (makes gesture with thumb and forefinger a few angstroms apart), bacteria are this big: (makes gesture with thumb and forefinger a few microns apart). OK, that's not overly helpful, the point being, you can filter bacteria out of water a whole hell of a lot easier than you can filter out dissolved arsenic.
- niels_olson 16y ago
  Couple of thoughts: 1) precipitating arsenic salts directly might be easier and a whole hell of a lot easier to provably run to completion. 2) to filter out bacteria, you'd have to grow bacteria. In addition to arsenic, you'd also have to add sugar and protein. Last I checked, Islam take a pretty hard line on beer.
  - freiheit 16y ago
    However, beer is made with yeast, not bacteria. And from what I can tell, most reasonable forms of Islam interpret the beer thing as forbidding intoxication. I don't think any forbid bread (solid beer), for instance. Yogurt and pickles are also made with bacterial processes and I don't think they're forbidden in Islam.

dotBen 16y ago

Back in the discussion thread pre-announcement a few days back, I mentioned Mono Lake as potentially being a source for this (http://news.ycombinator.com/item?id=1953749 http://news.ycombinator.com/item?id=1953749 and http://news.ycombinator.com/item?id=1953756 http://news.ycombinator.com/item?id=1953756). I just wanted to reiterate my suggestion for any bio-geeks living in the Bay Area - Mono Lake is only 2hrs drive from Bay Area and it is FASCINATING. I would really encourage anyone who is interested in ecology and biochemistry to go check it out if you are passing through to Mammouth Lakes for snowboarding or taking a trip to Yosemite which is next door.

hyperbovine 16y ago

Do you have any basis for the claim the 760k years would not be enough time for such a feature to arise? After all, some surprisingly complicated things (http://en.wikipedia.org/wiki/Evolution_of_the_eye http://en.wikipedia.org/wiki/Evolution_of_the_eye) are believed to have evolved (more than once) over shorter periods.

philwelch 16y ago
Number of years is mathematically irrelevant. Number of generations is mathematically relevant. Bacteria produce new generations prodigiously. Consider: antibiotics were invented less than a century ago, and bacteria have already evolved a resistance to penicillin. That's probably more than humans have evolved for 100,000 years. 100 years is like five generations for humans, but billions of generations for a bacteria. 760,000 years? That's tons of time for bacteria. Especially since bacteria are pretty simple; more complicated life has a much harder time evolving.
- Jabbles 16y ago
  Assuming bacteria reproduce once per day, a century would be ~30000 generations. Not billions. 760,000 years ~ 3e8 days, whether that is "tons of time" I can't comment.
  - philwelch 16y ago
    Assuming bacteria reproduce once per day I think that's an underestimate, by at least an order of magnitude.

dnautics 16y ago

"I'd be astonished if the arsenophile(?) evolved there in that short a time span" Why not? http://en.wikipedia.org/wiki/Berkeley_Pit#Extremophiles http://en.wikipedia.org/wiki/Berkeley_Pit#Extremophiles BTW, the ATP-AMP reaction is not a electrochemical reduction reaction, it's rather the mundane hydrolysis of a phosphodiester bond. We don't know what the energy potential of an arsenodiester bond is (although some speculation is that it carries a bit less energy).

cKeyser 16y ago

I'd use the word arsenotolerant instead. The cells still preferentially utilize phosphorous when given the option. The prefix phile generally implies that they require such conditions to live, like a thermophile isn't viable at a temperature below (roughly) 40 C. This organism would have no trouble growing in the absence of Arsenic. =)