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Thread: NASA Finds New Life Form

  1. #1 NASA Finds New Life Form 
    Forum Freshman 6nqpnw's Avatar
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    Though it's right here on planet Earth, NASA has found new life with its DNA lacking phosphorus and substituted with arsenic ::: previously thought as impossible.


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    Forum Freshman 6nqpnw's Avatar
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    Here's another story from a couple years ago about the same bacteria before realizing its DNA was built with arsenic.

    Also, during the live tele-conference at NASA (about an hour ago), the 'experts' drove home the point that the bacteria isn't 100% devoid of phosphorus, but has an insignificant amount that's incapable of sustaining life / growth.

    Felisa Wolfe-Simon seems to be the fore-runner spearheading this research and is quite the fire-cracker, IMO. I haven't found a copy yet, but she says she's released a paper detailing her research on bacterium GFAJ-1.


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    Universal Mind John Galt's Avatar
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    The item is published in Science, 2 December 2010.

    Abstract
    Life is mostly composed of the elements carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. Although these six elements make up nucleic acids, proteins, and lipids and thus the bulk of living matter, it is theoretically possible that some other elements in the periodic table could serve the same functions. Here, we describe a bacterium, strain GFAJ-1 of the Halomonadaceae, isolated from Mono Lake, California, which substitutes arsenic for phosphorus to sustain its growth. Our data show evidence for arsenate in macromolecules that normally contain phosphate, most notably nucleic acids and proteins. Exchange of one of the major bioelements may have profound evolutionary and geochemical significance.

    The full paper is only available by subscription or payment.


    This is dramatic news. A question that springs to mind is whether this feature is ancient, representing a truly primeval strain, or is the result of a recent - geologically speaking - mutation.
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    Forum Professor Zwirko's Avatar
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    The press coverage of this is insane.

    Calm down people, it's not a new form of life. Interesting stuff nevertheless...

    Ophiolite, I can't answer your question specifically but I can point out that Mono Lake is quite young geologically speaking (less than a million years?) and that the bacterium itself does not appear to belong to an oddball group located on some obscure branch of the tree of life.

    It's not clear to me whether this arsenate-DNA is naturally occurring or was just observed in the lab as a result of imposed conditions.
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    Administrator KALSTER's Avatar
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    Here is the Wiki article with links at the bottom: LINK.

    Very interesting indeed!
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    Universal Mind John Galt's Avatar
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    Quote Originally Posted by Zwirko
    Ophiolite, I can't answer your question specifically but I can point out that Mono Lake is quite young geologically speaking (less than a million years?) and that the bacterium itself does not appear to belong to an oddball group located on some obscure branch of the tree of life.
    The Wikipedia article on Mono Lake, which sprang into existence upon this paper's release, suggests the lake is 760,000 years old. That's pretty old for a lake: lakes are very short lived phenomena, geologically speaking. The article suggests it may be the remnant of a much larger lake that covered much of Nevada and Utah.

    If the organism is simply a 'normal' bacterrium which has acquired this ability to use arsenic rather than phosphorus, then that extends the range of adaptability of micro-organisms and suggests that primitive extra-terrestrial life should be more commonplace than we might hitherto have estimated.

    I confess I was hoping it might have been a truly ancient strain. I have a suspicion, born out of desire rather than science, that there are a handful of truly different organisms somewhere on the planet, just waiting to be discovered.
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    Your Mama! GiantEvil's Avatar
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    The GFAJ-1 Wiki mentions "origin of life" and "hydrothermal vents" so it's possible that this bacterium could be analogous to the "Coelacanth" as concerns longevity of species existence; http://en.wikipedia.org/wiki/Caelocanth.
    It's not that surprising that an organism might use arsenic in place of phosphorous, both elements are in the same group and have identical oxidation states.
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    Forum Freshman 6nqpnw's Avatar
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    Though it may not be an ancient organism, it very well could still be the origin of life on our planet. My understanding of young Earth (prior to the pale blue dot) was volcanic, volatile and pressumed inhospitable of sustaining life; GFAJ-1 shows the hostile environment could have sustained life long enough until more stable elements were abundant for life to thrive / evolve.

    @Ophio ::: Thx for hunting down the paper and posting the abstract.
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    Forum Professor jrmonroe's Avatar
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    Here's a 2003 article by other researchers on the "biogeochemical arsenic cycle" (phew!) in Mono Lake.

    some prokaryotes have evolved biochemical mechanisms to exploit arsenic oxyanions (i.e., arsenate and arsenite); they can use them either as an electron acceptor for anaerobic respiration (arsenate), or as an electron donor (arsenite) to support chemoautotrophic fixation of CO2 into cell carbon.

    For the past several years our research has focused on the occurrence and biogeochemical manifestations of these processes in Mono Lake
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    I've been doing a bit of reading on this lately(too much, I need to study!) and what I really would like to know is the relative size differences between the phosphodiester and arsenodiester bond lengths in the DNA. I cannot imagine they are equal, and the interesting situation comes then that, with every replication, and random insertion of dNTPs and dNTAs, there could potentially be differences in length between the strands at different portion of the double helix. These distortions could possibly have effects on gene regulation. Further, if there was a sudden change in environment, with say phosphorus becoming very scarce, or very abundant, which could result in replication only incorporating one of the two. Even if the original chromosome was mixed, the new fairly pure strands could differ in length so significantly that base pairing would be sterically hindered, forcing DNA synthesis to halt.
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    An interesting "takedown" of the Wolfe-Simon et al paper: Arsenic-associated bacteria (NASA's claims).

    And another: Arsenate-based DNA: a big idea with big holes

    I'm starting to wonder if this is yet another example of bad science and even worse science reporting.
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  13. #12  
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by Zwirko
    I'm starting to wonder if this is yet another example of bad science and even worse science reporting.
    That may be going a little far. A group of researchers have reported two things: observations and their interpretation of those observations. The observations are probably solid and given that details of their methodology have been provided then surely that consitutes good science.

    Their interpretation is questionable, certainly, but that is always likely to be the case with radical, truly ground breaking research. It is now up to other researchers to approach the problem, perhaps with different analytical techniques, to see if they come up with another suite of observations that support or falsify the interpretation.

    I also notice that no one is, apparently, contesting the substitution of arsenic in in ATP and lipids, but only as part of the DNA structural skeleton.
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