Mysterious bacterium in California: arsenate-based life

[zoogs]

http://www.scientificamerican.com/article.cfm?id=arsenic-life

 

Pretty exciting news I think, but a little sensationalized in the Washington Post link I threw up earlier.

 

Life as we know it is remarkably diverse and adaptive, permitting organisms to gain a toehold in some of the most outwardly inhospitable places on the planet. But it tends to rely on a tidy, predictable array of six nutrient elements, a modest alphabet of basic biology that leaves open the possibility of other combinations making up entirely different kinds of biological activity. Life as we know it, then, might not be all there is—for either terrestrial or extraterrestrial biology.

 

That possibility looks more promising in the light of a new study describing a bacterium isolated from California's Mono Lake that can use arsenic, which is usually poisonous to life, as one of its key nutrient elements. The microbe can even take up arsenic into its biomolecules, replacing phosphorus as a structural building block in DNA and possibly in energy-carrying molecules such as adenosine triphosphate (ATP) as well. The study appeared online December 2 in Science.

 

More than anything, it seems to be an example of adaptive life in a significant way we have never previously observed, rather than a discovery of 'alien' or new life on earth. Could have some interesting implications though.

 

It is also a bit remarkable to me how a respectable article in a pretty respectable science for the masses magazine, can get such loony comments on it. Like HowardB - missed the point completely.

[Husker_x]

Still, better get out the red pen for the textbooks. This is a big deal.

[zoogs]

The more I read it though, the less exciting it seems to get.

 

To look for organisms that could use arsenic as a nutrient, the researchers inoculated sediments from Mono Lake into a growth medium, adding arsenic but not phosphorus. They isolated a strain of gammaproteobacteria called GFAJ-1 that grew in arsenate-rich conditions but did not grow when deprived of both arsenate and phosphate. "It grows better with phosphorus, but it grows just fine with arsenic," Oremland says.

 

Arsenate ions are just substituting here if I am reading correctly. Not sure my calling this arsenate-based life is accurate. It seems to be normal life in every way. To use a football analogy, it's like the Patriots losing Tom Brady (phosphorous) and having to roll with Matt Cassel (arsenic). Sure they did just fine, but they would have done better with Brady, and it's not like they made the playoffs that year.

 

What the paragraph quoted there seems to say is that the GFAJ-1 can grow with arsenic, or with phosphorous, but not neither. It would be a lot more interesting and alien if it were some kind of organism that could not grow with our conventional building blocks and had different, unimaginable mechanisms...instead of one that is the same in every way, but just making the best use of its environmental resources.

 

Granted we didn't know it was possible to substitute the phosphate with arsenate ions, but that was basically the hypothesis of one of the biologists here. They went to an arsenic-rich lake to pull samples to test it and found evidence that the substitution was occurring. I think this is more of a footnote "...and by the way, this can also happen." It makes the possibility of wild and fanciful mechanisms of life and maybe alien life all the more tangible, though. The exciting part of it is "Well, if they can do that, who knows what other kind of life there could be...", rather than these particular bacteria.

[Husker_x]

The more I read it though, the less exciting it seems to get.

 

To look for organisms that could use arsenic as a nutrient, the researchers inoculated sediments from Mono Lake into a growth medium, adding arsenic but not phosphorus. They isolated a strain of gammaproteobacteria called GFAJ-1 that grew in arsenate-rich conditions but did not grow when deprived of both arsenate and phosphate. "It grows better with phosphorus, but it grows just fine with arsenic," Oremland says.

 

Arsenate ions are just substituting here if I am reading correctly. Not sure my calling this arsenate-based life is accurate. It seems to be normal life in every way. To use a football analogy, it's like the Patriots losing Tom Brady (phosphorous) and having to roll with Matt Cassel (arsenic). Sure they did just fine, but they would have done better with Brady, and it's not like they made the playoffs that year.

 

What the paragraph quoted there seems to say is that the GFAJ-1 can grow with arsenic, or with phosphorous, but not neither. It would be a lot more interesting and alien if it were some kind of organism that could not grow with our conventional building blocks and had different, unimaginable mechanisms...instead of one that is the same in every way, but just making the best use of its environmental resources.

 

Granted we didn't know it was possible to substitute the phosphate with arsenate ions, but that was basically the hypothesis of one of the biologists here. They went to an arsenic-rich lake to pull samples to test it and found evidence that the substitution was occurring. I think this is more of a footnote "...and by the way, this can also happen." It makes the possibility of wild and fanciful mechanisms of life and maybe alien life all the more tangible, though. The exciting part of it is "Well, if they can do that, who knows what other kind of life there could be...", rather than these particular bacteria.

 

I think it also expands the parameters in the search for life. What else is possible?

[HuskersNow]

It seems to me that many people assume that life has to be carbon based, just because life on earth is. I think that is a very biased view of things. For all we know, most alien life is completely different than life here on earth.

[zoogs]

I don't think that's an unchallenged assumption, but to date there has been no evidence otherwise. I think most assume if there is life out there it will be very different than what we understand, but we have had no chance to observe/study anything different than what we know. This is maybe the most radical departure from traditional we have observed.

 

Don't mistake the title; this life is very much carbon based. It is phosphorous that is being substituted out with arsenic.

[HuskersNow]

I don't think that's an unchallenged assumption, but to date there has been no evidence otherwise. I think most assume if there is life out there it will be very different than what we understand, but we have had no chance to observe/study anything different than what we know. This is maybe the most radical departure from traditional we have observed.

 

Don't mistake the title; this life is very much carbon based. It is phosphorous that is being substituted out with arsenic.

I understand that this organism is carbon based, but I was just explaining that many people usually assume that life elsewhere will be carbon based.

 

For all we know, we could eventually discover life forms that are a radical departure from anything that we have ever observed.

[Landlord]

[NUance]

Uh, yeah. This is earth shattering.

 

 

 

//nuance thinking, “Wow, I didn’t know these guys had such big brains.”

[knapplc]

I think this kind of thing makes such big news because so many people just read what's in their textbooks and don't think "outside the box" to use an over-used phrase. Of course life can be based on any kind or combination of elements. The presumption that water is essential to life is a fallacy as well - water is simply the liquid medium for life as we know it, and to presume that where there is no water, there is no life, is a fallacy. As we are better able to explore our own solar system we'll quite possibly find at least microbial life in places like Venus, Ganymede and Titan, and I would be surprised if there were nothing on Europa.

 

There's life "out there." There's probably life on tens of millions of planets and moons. Most likely there's quite a bit of life that resembles Earth-like life, but most likely there's a BUNCH of life that would completely freak out even the most open-minded theorists.

 

For as "cutting edge" as science gets, at times it also gets quite stodgy. Even biologists get dogmatically bogged down in what's in front of their nose. That's why stuff like this makes huge headlines, and why our first contact with aliens will be so earth-shattering to so many, and for the wrong reasons.

[CornHOLIO]

-----thought for sure this was goin' ta be a joke about some of the arseholes in California.

[BIGREDFAN_in_OMAHA]

Arsenic based life form appears to be correct:

 

http://allmediany.com/details_news_article.php?news_artid=412

[HuskerNLimbo]

The more I read it though, the less exciting it seems to get.

 

To look for organisms that could use arsenic as a nutrient, the researchers inoculated sediments from Mono Lake into a growth medium, adding arsenic but not phosphorus. They isolated a strain of gammaproteobacteria called GFAJ-1 that grew in arsenate-rich conditions but did not grow when deprived of both arsenate and phosphate. "It grows better with phosphorus, but it grows just fine with arsenic," Oremland says.

 

Arsenate ions are just substituting here if I am reading correctly. Not sure my calling this arsenate-based life is accurate. It seems to be normal life in every way. To use a football analogy, it's like the Patriots losing Tom Brady (phosphorous) and having to roll with Matt Cassel (arsenic). Sure they did just fine, but they would have done better with Brady, and it's not like they made the playoffs that year.

 

What the paragraph quoted there seems to say is that the GFAJ-1 can grow with arsenic, or with phosphorous, but not neither. It would be a lot more interesting and alien if it were some kind of organism that could not grow with our conventional building blocks and had different, unimaginable mechanisms...instead of one that is the same in every way, but just making the best use of its environmental resources.

 

Granted we didn't know it was possible to substitute the phosphate with arsenate ions, but that was basically the hypothesis of one of the biologists here. They went to an arsenic-rich lake to pull samples to test it and found evidence that the substitution was occurring. I think this is more of a footnote "...and by the way, this can also happen." It makes the possibility of wild and fanciful mechanisms of life and maybe alien life all the more tangible, though. The exciting part of it is "Well, if they can do that, who knows what other kind of life there could be...", rather than these particular bacteria.

 

I think this is still a HUGE discovery in the scientific world.

 

I get what you're saying in your Brady vs Cassel comparison, but I think what is truly interesting is the point that this organism can not only sustain life, but grow in the presence of arsenic with or without the presence of phosphorous.

 

Sure, if this bacteria had an option of using phosphorous over arsenic, it would clearly be a better nutrient source to use phosphorous. However, the fact that is bacteria can actually use arsenic in the same manner as phosphorous in the multiple mechanisms of the cell, including replacement of DNA backbone to one that uses arsenic, to be able to survive, is a big deal!

 

Ah science. lol.

[Husker_x]

I think this kind of thing makes such big news because so many people just read what's in their textbooks and don't think "outside the box" to use an over-used phrase. Of course life can be based on any kind or combination of elements. The presumption that water is essential to life is a fallacy as well - water is simply the liquid medium for life as we know it, and to presume that where there is no water, there is no life, is a fallacy. As we are better able to explore our own solar system we'll quite possibly find at least microbial life in places like Venus, Ganymede and Titan, and I would be surprised if there were nothing on Europa.

 

There's life "out there." There's probably life on tens of millions of planets and moons. Most likely there's quite a bit of life that resembles Earth-like life, but most likely there's a BUNCH of life that would completely freak out even the most open-minded theorists.

 

For as "cutting edge" as science gets, at times it also gets quite stodgy. Even biologists get dogmatically bogged down in what's in front of their nose. That's why stuff like this makes huge headlines, and why our first contact with aliens will be so earth-shattering to so many, and for the wrong reasons.

 

And that's based on...? The reason biologists might even in theory be 'dogmatically bogged down' is that we have our data points about life and then a whole lot of squat to the contrary. I mean to me it would be like saying to someone in the 1800s that they were dogmatically bogged down in Newtonian physics. Of course they were. Until someone like Einstein comes along and flips the script, or somebody shows up with a vial of mercury microbes, we're actually better served by keeping our search to planets with water, given the scope we're dealing with. Until your theory has the evidence or the math, it's not a serious point, even if it shows promise.

 

I fundamentally agree with your point, though, which is that we had better prepare ourselves for the bizarre realities that will likely be coming with the space age.

[knapplc]

I think this kind of thing makes such big news because so many people just read what's in their textbooks and don't think "outside the box" to use an over-used phrase. Of course life can be based on any kind or combination of elements. The presumption that water is essential to life is a fallacy as well - water is simply the liquid medium for life as we know it, and to presume that where there is no water, there is no life, is a fallacy. As we are better able to explore our own solar system we'll quite possibly find at least microbial life in places like Venus, Ganymede and Titan, and I would be surprised if there were nothing on Europa.

 

There's life "out there." There's probably life on tens of millions of planets and moons. Most likely there's quite a bit of life that resembles Earth-like life, but most likely there's a BUNCH of life that would completely freak out even the most open-minded theorists.

 

For as "cutting edge" as science gets, at times it also gets quite stodgy. Even biologists get dogmatically bogged down in what's in front of their nose. That's why stuff like this makes huge headlines, and why our first contact with aliens will be so earth-shattering to so many, and for the wrong reasons.

 

And that's based on...? The reason biologists might even in theory be 'dogmatically bogged down' is that we have our data points about life and then a whole lot of squat to the contrary. I mean to me it would be like saying to someone in the 1800s that they were dogmatically bogged down in Newtonian physics. Of course they were. Until someone like Einstein comes along and flips the script, or somebody shows up with a vial of mercury microbes, we're actually better served by keeping our search to planets with water, given the scope we're dealing with. Until your theory has the evidence or the math, it's not a serious point, even if it shows promise.

 

I fundamentally agree with your point, though, which is that we had better prepare ourselves for the bizarre realities that will likely be coming with the space age.

 

The first part, of course, is based on conjecture, but "backed up" with probability. There are so many galaxies out there. So many stars.

 

The use of the word "dogmatic" is probably bothering you more than anything, and it's an acceptable excuse to argue that we have no other data points with which to work and that non-carbon-based life is (or was) conjecture, but that doesn't change the fact that we're mostly anticipating life to resemble us, and that's not a given.