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Life on Earth requires six basic ingredients—carbon, hydrogen, nitrogen, oxygen, sulfur and phosphorus. Those six elements are the building blocks for DNA and RNA, along with proteins and fats. Which means they're essential for life—as we know it. But it might be time to update that list. Because scientists have found a bacterium that can do without phosphorus—live on arsenic instead.
The researchers had a hunch a bug like this might exist, because arsenic has some chemical properties in common with phosphorus. So they collected mud from California's Mono Lake, where the waters are naturally salty, and laced with arsenic. Back in the lab, they cultured microbes from that mud. But instead of adding phosphorus to the cultures to help the bugs grow, they added varying levels of arsenic.
One bacterial strain continued to thrive. And tests confirmed that the organisms compensated for the lack of phosphorus by building their DNA with arsenic instead. The research appears in the journal Science. [Felisa Wolfe-Simon et al., "A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus"]
This is the first known life form that seems to be able to swap out one of life's fundamental building blocks with another element. So for astrobiologists hunting for life in space, don’t rule out places filled with poison.
—Christopher Intagliata
[The above text is an exact transcript of this podcast.]
For more, see Mono Lake Bacterium Exhibits Exotic Arsenic-Driven Biological Activity
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9 Comments
Add CommentThis is a very interesting finding... It would be exciting to see if any of those microbes in the natural arsenic laced enviroment have done this outside the lab.
Reply | Report Abuse | Link to thisAlso if this is possible with arsenic, what about the possibility of swapping out any of the other blocks with similarly sized alternate elements, given the right conditions?
Don't think any other planets with liquid water have been confirmed yet. Liquid water is a universal solvent that allows chemicals to freely float, make contact each other and produce reactions. As I understand, no other fluid can provide this capability.
Reply | Report Abuse | Link to thisEven these microbes were extracted from a lake.
Well, the experiment is pretty cool and from the successful swap of phosphorous with arsenic, can I do a speculate that actually it is the certain propriety units in the six basic ingredients of life that vital to create and sustain life but not the whole elements necessary.
Reply | Report Abuse | Link to thisBTW,I didn't understand the relation between the first and the second sentence in the final paragraph. What's the logic? Could anybody explain it to me? Why the author concluded this "So for astrobiologists hunting for life in space, don’t rule out places filled with poison." from the initial idea of that part? Hope someone can give me a clue,thx!
Well, the experiment is pretty cool and from the successful swap of phosphorous with arsenic, can I do a speculate that actually it is the certain propriety units in the six basic ingredients of life that vital to create and sustain life but not the whole elements necessary.
Reply | Report Abuse | Link to thisBTW,I didn't understand the relation between the first and the second sentence in the final paragraph. What's the logic? Could anybody explain it to me? Why the author concluded this "So for astrobiologists hunting for life in space, don’t rule out places filled with poison." from the initial idea of that part? Hope someone can give me a clue,thx!
I think this article explains the 'alien life' connection a little more thoroughly:
Reply | Report Abuse | Link to thishttp://www.scientificamerican.com/article.cfm?id=arsenic-life
There had been some noise on the web about the implications for finding life on other planets, or even that this bacterium represented life from space.
The first problem for extraterrestrial life hunters is finding a nice place with confirmed liquid water. Worrying about trace elements should be much further down on the list of issues for alien life forms.
because arsenic is a severe poisonous element
Reply | Report Abuse | Link to thisFrom school chemistry let me point all you folk to the periodic table. Phosphorus and Arsenic are both in group VA under Nitrogen, they must behave similarly except that their size increases.
Reply | Report Abuse | Link to thisAt different temperatures, different solvents could provide a medium for life, even if the characteristics of the solvent are not as unique as water. Water owes its character to hydrogen bonding. Perhaps an energy form of sentient life needs no solvent at all. How about sentient life in the sun and other stars.
I think it can be inferred from the chemical used in the experiment ,coz it seems that arsenic is always seen as a kind of poison,but microbes can grow there,so if someone wants to find life in space,the places filled with poison may be not ruled out.By the way,I am a chinese college student,it's my first time to make a comment,hope my reply can help you~~~
Reply | Report Abuse | Link to thisThank you buddies! jtdwyer,xmukakaka and xiaobai024, you guys helped me get out of puzzle =)
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