New life form found on Earth: Deadly arsenic breathes life into organisms (Update, Video)

Dec 02, 2010 by Kerry Sheridan
Scientists have found the first known living organism that incorporates arsenic into the working parts of its cells. What's more, the arsenic replaces phosphorus, an element long thought essential for life. Staff scientist Sam Webb led the research undertaken at the Stanford Synchrotron Radiation Lightsource located at SLAC National Accelerator Laboratory. The results were published online today in Science Express. Credit: Brad Plummer/SLAC

(PhysOrg.com) -- Evidence that the toxic element arsenic can replace the essential nutrient phosphorus in biomolecules of a naturally occurring bacterium expands the scope of the search for life beyond Earth, according to Arizona State University scientists who are part of a NASA-funded research team reporting findings in the Dec. 2 online Science Express.

It is well established that all known life requires phosphorus, usually in the form of inorganic phosphate. In recent years, however, astrobiologists, including Arizona State University professors Ariel Anbar and Paul Davies, have stepped up conversations about alternative forms of life. Anbar and Davies are coauthors of the new paper, along with ASU associate research scientist Gwyneth Gordon. The lead author is Felisa Wolfe-Simon, a former postdoctoral scientist in Anbar's research group at ASU's School of Earth and Space Exploration and Department of Chemistry and Biochemistry in the College of Liberal Arts and Sciences.

"Life as we know it requires particular chemical elements and excludes others," says Anbar, a biogeochemist and astrobiologist who directs the astrobiology program at ASU. "But are those the only options? How different could life be?" Anbar and Wolfe-Simon are among a group of researchers who are testing the limits of life's chemical requirements.

"One of the guiding principles in the search for life on other planets, and of our astrobiology program, is that we should 'follow the elements,'" says Anbar. "Felisa's study teaches us that we ought to think harder about which elements to follow."

This video is not supported by your browser at this time.
This video is a montage about life released in conjunction with the finding by researchers working in the harsh environment of Mono Lake, Calif. They discovered microorganisms able to thrive and reproduce using arsenic, changing the fundamental knowledge about what comprises all known life on Earth. Video: NASA

Wolfe-Simon adds: "We took what we do know about the 'constants' in biology, specifically that life requires the six elements CHNOPS (carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur) in three components, namely DNA, proteins and fats, and used that as a basis to ask experimentally testable hypotheses even here on Earth."

From this viewpoint, rather than highlighting the conventional view of the "diversity" of life, all life on Earth is essentially identical, she says. However, the microbe the researchers have discovered can act differently.

Davies has previously speculated that forms of life different from our own, dubbed "weird life," might even exist side-by-side with known life on Earth, in a sort of "shadow biosphere." The particular idea that arsenic, which lies directly below phosphorous on the periodic table, might substitute for phosphorus in life on Earth, was proposed by Wolfe-Simon and developed into a collaboration with Davies and Anbar. Their hypothesis was published in January 2009, in a paper titled "Did nature also choose arsenic?" in the International Journal of Astrobiology.

"We not only hypothesized that biochemical systems analogous to those known today could utilize arsenate in the equivalent biological role as phosphate," notes Wolfe-Simon "but also that such organisms could have evolved on the ancient Earth and might persist in unusual environments today."

Wolfe-Simon, now a NASA astrobiology research fellow in residence at the U.S. Geological Survey, was one of the participants, along with Anbar, at a workshop titled "Tree or Forest? Searching for Alternative Forms of Life on Earth," that was organized in December 2006 by the BEYOND Center, a "cosmic think tank" at ASU.

"That's where it all began," says Davies, a cosmologist, astrobiologist, theoretical physicist and director of the BEYOND Center.

"Felisa's talk was memorable for being a concrete proposal," Davies says. "Many of the talks at the workshop discussed searching for radically alternative forms of life with suggestions of the form 'maybe something roughly like this,' or 'maybe a bit like that.' But Felisa said, quite explicitly, 'this is what we go look for.' And, she did."

"The idea was provocative, but it made good sense," notes Anbar. "Arsenic is toxic mainly because its chemical behavior is so similar to that of phosphorus. As a result, organisms have a hard time telling these elements apart. But arsenic is different enough that it doesn't work as well as phosphorus, so it gets in there and sort of gums up the works of our biochemical machinery."

An transmission electron micrograph image of the bacterium, showing vacuole pockets within its cell walls. Image credit: Science.

After leaving ASU, Wolfe-Simon began a collaboration with Ronald Oremland of the U.S. Geological Survey to chase down the hypothesis. Oremland was a natural choice to bring into the project because he is a world expert in arsenic microbiology. What Wolfe-Simon discovered is presented in the Science Express paper titled "A bacterium that can grow by using arsenic instead of phosphorus."

The latest discovery is all about a bacterium – strain GFAJ-1 of the Halomonadaceae family of Gammaproteobacteria – scooped from sediments of eastern California's Mono Lake, which is extremely salty with naturally high levels of arsenic.

In the laboratory, the researchers successfully grew microbes from the lake on a diet that was very lean on phosphorus, but included generous helpings of arsenic.

Key issues that the researchers needed to address were the levels of arsenic and phosphorus in the experiments and whether arsenic actually became incorporated into the organisms' vital biochemical machinery, such as DNA, proteins and the cell membranes. A variety of sophisticated laboratory techniques was used to nail down where the arsenic went, including mass spectrometry measurements by Gordon at the W.M. Keck Foundation Laboratory for Environmental Biogeochemistry at ASU.

Commenting on the significance of the discovery, Davies says: "This organism has dual capability. It can grow with either phosphorous or arsenic. That makes it very peculiar, though it falls short of being some form of truly 'alien' life belonging to a different tree of life with a separate origin. However, GFAJ-1 may be a pointer to even weirder organisms. The holy grail would be a microbe that contained no phosphorus at all."

Davies predicts that the new organism "is surely the tip of a big iceberg, and so has the potential to open up a whole new domain of microbiology."

It is not only scientists, however, who will be interested in this discovery. "Our findings are a reminder that life-as-we-know-it could be much more flexible than we generally assume or can imagine," says Wolfe-Simon, noting that because microbes are major drivers of biogeochemical cycles and disease this study may open up a whole new chapter in biology textbooks.

"Yet, this story isn't about arsenic or Mono Lake," Wolfe-Simon says. "If something here on Earth can do something so unexpected, what else can life do that we haven't seen yet? Now is the time to find out."

Graphic on the findings of a NASA funded study that claims to redefine the building blocks of life, and offers new hope in the search for other organisms on Earth and beyond.

------------------------

Earlier story (Updated 12/2/2010 12:40pm EST):

NASA will announce later Thursday an explosive finding in the search for new life forms on Earth and beyond, a discovery that shifts what scientists consider necessary for life to exist.

While details of the study are under embargo until 2:00 pm (1900 GMT), media leaks have already established that the findings relate to a bacteria that survives and grows on arsenic, uncovered deep in a California lake.

The discovery of a bacteria that can incorporate arsenic into its DNA adds a new dimension to what has long been accepted as the of life as we know it.

Until now, biologists have said life requires six elements, known by the acronym CHNOPS: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.

Those elements must take shape within three components of an organism: DNA, protein and fats.

Every life form has DNA. It is the identifier that, for example, allows humans to reproduce other humans while mice give birth to mice.

In other words, DNA is a molecule (called ) that gives life its biological instructions.

All known life needs phosphorus, which serves as the backbone for these that make up life's .

Arsenic is right below phosphorus on the periodic table, and the two are very similar.

However arsenic is different enough that it cannot substitute for , and typically slows down an organism enough that it kills it, hence why it is considered poison.

But one of the speakers scheduled to appear at the press conference later Thursday, Felisa Wolfe-Simon, wondered if it had always been that way.

In 2009 she co-authored a paper called "Did nature also choose arsenic?"

In that paper, she wrote: "We hypothesize that ancient biochemical systems, analogous to but distinct from those known today, could have utilized arsenate in the equivalent biological role as .

" utilizing such 'weird life' may have supported a 'shadow biosphere' at the time of the origin and early evolution of life on Earth or on other planets.

"Such organisms may even persist on Earth today, undetected, in unusual niches."

Of course, another condition for life to exist is adaptability. All life must have adapted, or adapt now or in the future, in order to survive.

Previous scientific discoveries have found examples of life forms existing on Earth in extreme heat, cold, acidic environments and airless underground pockets.

Scientists have also already found examples of bacteria that use arsenic the way humans use food and oxygen for energy.

So it is possible that this odd bacteria was only doing what it had to in order to survive in a lake with unusually high levels of , salt and other minerals.

NASA's vague announcement earlier this week of a press conference on "an astrobiology finding that will impact the search for evidence of extraterrestrial life" set the Internet abuzz with speculation.

Astrobiology relates to the study of life in the universe, including its origin and evolution, where it is located and how it might survive in the future.

The full details of the study will be published later today in the journal Science Express, at the same time as the NASA press conference begins.

Other speakers are to include Mary Voytek, director of the Astrobiology Program at NASA; Pamela Conrad, a NASA astrobiologist; Steven Benner, distinguished fellow at the Foundation for Applied Molecular Evolution; and James Elser, professor at Arizona State University.

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Provided by Arizona State University

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User comments : 27

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neoabraxas
3 / 5 (12) Dec 02, 2010
"This organism has dual capability. It can grow with either phosphorous or arsenic. That makes it very peculiar, though it falls short of being some form of truly 'alien' life belonging to a different tree of life with a separate origin. However, GFAJ-1 may be a pointer to even weirder organisms. The holy grail would be a microbe that contained no phosphorus at all."

Frankly this doesn't sound like something that would warrant a big press conference
waremi
3.3 / 5 (4) Dec 02, 2010
So is this just another extremophile that adapted to arsenic rich environments, but still uses Phosphorous in it’s DNA and RNA scaffolding? Or did it start as an ordinary organism and at some point evolve the ability to use phosphorous and arsenic interchangeably? Or is this an entirely new form of biology that has evolved parallel to our own?
Raveon
2.7 / 5 (3) Dec 02, 2010
Said it before and I'll say it again, the chances are good that the precursor to life as we know it is probably still around and waiting to be discovered. Getting closer with this but no cigar, still too complex..
lexington
not rated yet Dec 02, 2010
@Raveon: Why would you say that? I mean come on, you have to admit it's pretty stupid.
bmcghie
4.7 / 5 (3) Dec 02, 2010
Unless this organism doesn't use phosphorus at all... I fail to see why this warrants all the excitement. Yes, it's neat to find that something can behave in this manner, and yes this could indicate weirder biochemistries exist... but until we find THOSE, I'll say "neat" and wait for the real announcement.
Raveon
not rated yet Dec 02, 2010
Lexington: What's stupid about it unless you don't believe in evolution? Complex life and DNA didn't spring up out of nothing. It had to come from something simpler with a precursor to DNA. I think there are missing links just like fossils and they may still be around.
Dummy
1 / 5 (20) Dec 02, 2010
Evolution is a theory, not a fact.
lexington
not rated yet Dec 02, 2010
But there's no reason to think the molecular precursors to DNA would still be hanging around anywhere (well the constituent atoms are but that shouldn't count for anything).
SuicideSamurai
1.8 / 5 (5) Dec 02, 2010
Wouldn't warrant a big press conference? It sure does, these findings, amongst others suggest that there is a high likelihood of life existing wherever there is liquid water. Though "waremi" does bring up some good points that if true may countermand these findings.
Vsha
4.3 / 5 (12) Dec 03, 2010
@Dummy - your name was well chosen
typicalguy
not rated yet Dec 03, 2010
We need to find life that doesn't use DNA at all. If we find life on Earth that has some other mechanism to transfer it's genetic data than the DNA we are familiar with then we'll say with certainty that life is very common in the Universe (as it would have started on Earth at least two separate times). Evidently this bacteria has found a way to create DNA chains in a novel way but this is not alien life or even terrestrial life from a different family tree - we simply have to add a new branch to our current one.
kevinrtrs
1.9 / 5 (9) Dec 03, 2010
One of the guiding principles in the search for life on other planets, and of our astrobiology program, is that we should 'follow the elements,'" says Anbar. "Felisas study teaches us that we ought to think harder about which elements to follow."

This is a major misdirection - following the elements. It's not the elements that are essential to life, it's the information stored in the arrangement of those physical elements.
This is why the arsenic can replace the phosphorous and the organism still live.
Information can be stored in just about any kind of physical setup - we know this from our own experiences , e.g. magnetic storage vs optical storage vs stones arranged in certain patterns etc.
So in the living things it's more a case of HOW that information is processed and here size plays a big role with regards to energy usage etc. Then on top of that is the stability and immunity from accidental interference - which is why there are so many safeguards in human DNA.
kevinrtrs
1.5 / 5 (10) Dec 03, 2010
So the real question should be - where would we find a place [or person] that would be able to supply such life giving information?
Following the elements will simply be a waste of time because without the right information present, no life is possible. Whether that life is as we know it or is completely different.
Here I have to submit that I'm limiting myself to physical lifeforms. There might well be lifeforms that are NOT physical as we know it and hence this particular information content requirement might not be applicable to those.

antialias_physorg
4.6 / 5 (9) Dec 03, 2010
I fail to see why this warrants all the excitement.

The excitement is that if such microbes can use arsebnic and phosphorous interchangeably then it is quite possible that life (as we know it) could exist without phosphorous at all. This in turn means that the possible places where life may be found in the universe have just multiplied.

I'd say that this is BIG news.
antialias_physorg
4.8 / 5 (4) Dec 03, 2010
I fail to see why this warrants all the excitement.

The excitement is that if such microbes can use arsebnic and phosphorous interchangeably then it is quite possible that life (as we know it) could exist without phosphorous at all. This in turn means that the possible places where life may be found in the universe have just multiplied.

I'd say that this is BIG news.
Blakut
1 / 5 (2) Dec 03, 2010
We should send these bacteria to all the planets and moons in the Solar System. Also the other extremophiles. Man that sounds ... weird.
mabarker
1 / 5 (9) Dec 03, 2010
I think the darwinists should re-think their initial excitement. If arsenic were such a good substitute, some cells would surely use it. Since it isn't, the experiment should have provided a lesson on the narrow tolerances of life, not what evolutionists are imagining. A PhD non-darwinist stated, 'the enhanced fitness of the organism in an arsenic-enhanced environment compared to other organisms comes from additional chemical machinery that makes the arsenic bonds more stable. This comes at an overall co$t to the organism.' Back to square one.
mabarker
1 / 5 (11) Dec 03, 2010
Secular scientists should re-think their initial excitement. If arsenic were such a good substitute, some cells would surely use it. Since it isn't, the experiment should have provided a lesson on the narrow tollerances of life, not what evolutionists are imagining. A PhD non-darwinist stated, 'the enhanced fitness of the organism in an arsenic-enhanced environment compared to other organisms comes from additional chemical machinery that makes the arsenic bonds more stable. This comes at an orverall cost to the organism.'
Back to square one - again.
loreak
5 / 5 (13) Dec 03, 2010
Evolution is a theory, not a fact.


Gravity is theory, not a fact.
Skultch
5 / 5 (6) Dec 03, 2010
Since it isn't, the experiment should have provided a lesson on the narrow tollerances of life, not what evolutionists are imagining.


If life can exist, it will, regardless of costs lowering efficiency.

We don't need a lesson on the narrow tolerances of life. We already know that carbon wouldn't be created inside stars if physical laws were only slightly different.

OF COURSE we see a "fine tuned" universe. We are here to see it. This means nothing since existence is apparently so mind bogglingly enormous and old that we are but one of literally countless tries at this "stuff" thing.
Skeptic_Heretic
5 / 5 (5) Dec 03, 2010
Evolution is a theory, not a fact.

It is a theory and a fact. Just like Germs causing diseases is a theory and a fact. Just like the heliocentric theory is both a theory and a fact.

Learn what theory means.
A PhD non-darwinist stated, 'the enhanced fitness of the organism in an arsenic-enhanced environment compared to other organisms comes from additional chemical machinery that makes the arsenic bonds more stable. This comes at an orverall cost to the organism.'

So you have two costs, death by arsenic poisoning or learning to use arsenic in your biology to avoid death.

I think the net benefit is in not dying, what do you think?
antialias_physorg
5 / 5 (3) Dec 03, 2010
If arsenic were such a good substitute, some cells would surely use it.
In an environment where phosphorous is hard to come by (or not at all) a bad 'substitute' is better than none. In such an environment it IS more efficient to use arsenic.
Ethelred
5 / 5 (2) Dec 04, 2010
This is why the arsenic can replace the phosphorous and the organism still live.
Almost. The reason is that arsenic and phosphorus are very similar chemically. Just enough different that in most life if arsenic replaces phosphorus it screws thing up.

I think a few people here gave you a one on general principles. I gave you a five.

where would we find a place [or person] that would be able to supply such life giving information?
The environment is the place.

Following the elements will simply be a waste of time because without the right information present, no life is possible.
This is wrong at least in part. Following the elements is how we can see what other substitutions might exist. We already know where the information comes from. From the environment via Natural Selection.

Ethelred
Physorg should do themselves and us a favor
Stop the Ranking Insanity
Ethelred
5 / 5 (2) Dec 04, 2010
If arsenic were such a good substitute, some cells would surely use it.
Now we know that some do. The rest we know of are poisoned by it due its being enough different from phosphorus to screw things up in tightly tuned cells. There isn't much life in Lake Mono to compete with this so it doesn't tightly tuned.

Lake Mono is on love with shoes. It eats them. I managed to keep mine but it took an hour of cleaning.

Since it isn't, the experiment should have provided a lesson on the narrow tollerances of life,
Nonsense. There is no need for an experiment to show such a thing. Experiments show what they show. And models may or may need to be adapted. I don't see a problem here. Not much competition.

Back to square one - again.
True that you are back to your standard position. You refuse to learn from reality.

How about you tell us what happened to the Egyptians in the Flood?

Ethelred
Physorg should do themselves and us a favor
Stop the Ranking Insanity
Ethelred
not rated yet Dec 04, 2010
So you have two costs, death by arsenic poisoning or learning to use arsenic in your biology to avoid death.
NOW we have two forms of DNA. With phosphorus and with arsenic. Still the same basic thing but it does show that other ways of doings may be possible. This still has the same structure. Most likely can't survive in open competition with phosphorus only life.

The arsenic levels do make me wonder about all the birds that breed there. The lake looks like something from another world yet Highway 395 goes right past it. Same lake as you can see in the background in Clint Eastwood's High Plains Drifter.

Ethelred
Physorg should do themselves and us a favor
Stop the Ranking Insanity
Sonhouse
not rated yet Dec 04, 2010
Does anyone know how close the next element down, Antimony, is to Arsenic and phos? Could Sb too sub for phos?
Skeptic_Heretic
not rated yet Dec 04, 2010
Does anyone know how close the next element down, Antimony, is to Arsenic and phos? Could Sb too sub for phos?
I don't know if that would work. Antimony is more metal than organic. Arsenic is more organic than hetal. I'm not certain it would share the bond properties that arsenic and phosphorus do.

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