A new piece in the jigsaw of the origin of life

[Prebe]

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Science 27 October 2006:
Vol. 314. no. 5799, pp. 630 - 632
DOI: 10.1126/science.1130895
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Reports
-Hydroxy and -Amino Acids Under Possible Hadean, Volcanic Origin-of-Life Conditions Claudia Huber1 and Günter Wächtershäuser2*

To test the theory of a chemoautotrophic origin of life in a volcanic, hydrothermal setting, we explored mechanisms for the buildup of bio-organic compounds by carbon fixation on catalytic transition metal precipitates. We report the carbon monoxide–dependent formation of carbon-fixation products, including an ordered series of -hydroxy and -amino acids of the general formula R-CHA-COOH (where R is H, CH3,C2H5,orHOCH2 and A is OH or NH2) by carbon fixation at 80° to 120°C, catalyzed by nickel or nickel,iron precipitates with carbonyl, cyano, and methylthio ligands as carbon sources, with or without sulfido ligands. Calcium or magnesium hydroxide was added as a pH buffer. The results narrow the gap between biochemistry and volcanic geochemistry and open a new gateway for the exploration of a volcanic, hydrothermal origin of life.

1 Department of Organic Chemistry and Biochemistry, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching, Germany.
2 Weinstraße 8, D-80333 München, Germany.

* Present address: 209 Mill Race Drive, Chapel Hill, NC 27514, USA.

[lucimay]

that reads like a poem Prebe ACB. heh.

[sgt.null]

Volcanic Origin-of-Life Conditions

so tom cruise is right?

[Prebe]

Yes sarge. Big snakes and monkeys created from the hot intestines of earth slithering forth from volcanoes

Lucy: Guess you are right. It does have some poethical qualities.

[Fist and Faith]

I think I'd be very interested... if I had any idea what it was saying. *feeling kinda slow* I'll have to read it again a few times.

I'd like to know if anyone, anywhere, using any equipment they wanted, using any elements they wanted, setting up whatever conditions they wanted, has ever managed to create life.

[Prebe]

I'd like to know if anyone, anywhere, using any equipment they wanted, using any elements they wanted, setting up whatever conditions they wanted, has ever managed to create life.

I think we would have heard about it, if it had happened.

There are thought to have been several orders in the formation of what we know as life (known as levels of organisation):

1: Elements/ions -> (organic) molecule
2: (organic) molecule > polymer
3: Polymer -> organelle
4: Organelle -> cell
5: Cell -> organ/organism

This article is an exmple of a diferent hypothesis for step 1, where the most comon hypothesis so far has been that the energy for these processes have been provided by lightning or directly from the sun.

There are several good examples of 2 happening in laboratories.
3 is a lot harder, and has probably been a key point in the development of life as we know it. There are examples of self organising polymers/smaller molecules, that are capable of self replication, with the correct supply of molecules, but you wouldn't call that "life" necessarily. Protolife perhaps. And millions of these protolife "communities" must have existed, and from one of those sprang something a little more complex with a vastly large survival/reproduction capacity.

One of the difficult things to answer here is: What IS life anyway?

[Loredoctor]

One of the difficult things to answer here is: What IS life anyway?

Self-replicating information that has the capacity, though mutation, to adapt to a changing environment.

[Prebe]

By that definition (information) life has been created thousands of times in computers.

My problem with that definition is the amount of energy going into keeping 1 or 1000 organisms alive is aproximately the same. I like to use the energy input/expenditure (a metabolism) in my equation of life. I'm not sure what everybody else does.

So while your definition is arguably a valid one, so are many others. THe thing is, there doesn't really seem to be any scientific consensus.

[I'm Murrin]

By that definition (information) life has been created thousands of times in computers.

I'd say they fail to qualify for the 'changing environment' bit. They work in restricted systems predesigned to allow them to work.

[Prebe]

Whether the environment has been predesigned is immaterial according to Loremasters definition. You can create code that constantly changes, and some new chunks might funtion even in a new operating system for example. The fact that the basic building blocks are ones and zeros and not molecules is irrelevant unless you want to include some kind of energy metabolism in the definition.

[lucimay]

good thread Prebe.

[Fist and Faith]

One of the difficult things to answer here is: What IS life anyway?

Indeed.* But isn't there anything that is common to all known living organisms? If there is, then my question is whether that characteristic (or those characteristics) has been created from scratch under any circumstances.



*Data and Dr. Crusher couldn't come up with an answer. Of course, they had to deal with life-forms like Data. But here's their conversation again. It gets philosophical, but it starts out with what we're discussing.

Data: <I>What is the definition of life?</I>

Crusher: <I>That is a BIG question. Why do you ask?</I>

Data: <I>I am searching for a definition that will allow me to test an hypotheses.</I>

Crusher: <I>Well, the broadest scientific definition might be that life is what enables plants and animals to consume food, derive energy from it, grow, adapt themselves to their surrounding, and reproduce.</I>

Data: <I>And you suggest that anything that exhibits these characteristics is considered alive.</I>

Crusher: <I>In general, yes.</I>

Data: <I>What about fire?</I>

Crusher: <I>Fire?</I>

Data: <I>Yes. It consumes fuel to produce energy. It grows. It creates offspring. By your definition, is it alive?</I>

Crusher: <I>Fire is a chemical reaction. You could use the same argument for growing crystals. But, obviously, we don't consider them alive.</I>

Data: <I>And what about me? I do not grow. I do not reprodue. Yet I am considered to be alive.</I>

Crusher: <I>That's true. But you are unique.</I>

Data: <I>Hm. I wonder if that is so.</I>

Crusher: <I>Data, if I may ask, what exactly are you getting at?</I>

Data: <I>I am curious as to what transpired between the moment when I was nothing more than an assemblage of parts in Dr. Sung's laboratory and the next moment, when I became alive. What is it that endowed me with life?</I>

Crusher: <I>I remember Wesley asking me a similar question when he was little. And I tried desperately to give him an answer. But everything I said sounded inadequate. Then I realized that scientists and philosophers have been grappling with that question for centuries without coming to any conclusion.</I>

Data: <I>Are you saying the question cannot be answered?</I>

Crusher: <I>No. I think I'm saying that we struggle all our lives to answer it. That it's the struggle that is important. That's what helps us to define our place in the universe.</I>

[Loredoctor]

Whether the environment has been predesigned is immaterial according to Loremasters definition.

That's not the issue. All I am saying is that if you have an environment that changes - like the Earth - if the code changes (mutates) and some of it is successful, and that code has the capacity to replicate, then the successful code will flourish. By my definition, a computer/program does not fit that.

My problem with that definition is the amount of energy going into keeping 1 or 1000 organisms alive is aproximately the same.

You're probably reading too much into what I wrote. I never intimated this.

[Avatar]

Uh, I'm just gonna read this one for a while. It's early monday morning ok?

--A

[Zarathustra]

Self-replicating information that has the capacity, though mutation, to adapt to a changing environment.

I like that, but Prebe is right to point out a delineating distinction with the computer. What's the difference? Let's look at it literally.

Perhaps "life" is the organic material which enable this process of information replication--the "byproduct" of the process Loremaster is describing, which enables it to continue. The flesh or plant matter through which DNA perpetuates itself. You can look at living beings as "mere" vehicles for the transmission, perpetuation, and replication of DNA through time. DNA can't do it on its own. It needs a vehicle, a material organism, a peculiar cocoon of matter which it weaves around itself out of elements in its environment; a suitable modification of its local environment to enable its own continuation. It enfolds itself within a living pocket of matter.

This might seem obvious, not even worth mentioning, except for the problem Prebe brought up about computers. The absence of a self-designed cocoon of flesh--designed by the self-replicating information itself (DNA)--is what distinguishes the 1's and 0's from "living information." Really, I can't think of any other difference. Can you?

This seems to be the only reason why the same phenomenon inside a computer isn't alive. The computer is primary, built by us. It came first. And then we create self-replicating information which exists inside it, which is dependent upon the computer for its existence. But this dependency isn't like the DNA's dependency upon the flesh or plant matter. Bodies don't create DNA. DNA creates bodies. Is there something to this causal arrow? Can life be created top-down, rather than bottom-up? Or is this directional causation a necessary condition? Given sufficient technology, I can imagine this distinction being overcome (like with Star Trek's Data). But at what point is this distinction reversed?

A correlary question might be: why does DNA need living matter to perpetuate itself? Why do we never see DNA perpetuating itself though a cocoon of matter which isn't considered alive? Like rocks? Or (more plausibly) liquids? Or in the atmosphere? Is this what a virus is? The bare minimum vehicle for DNA transmission? If so, it still doesn't answer the question of why--in virtually every circumstance--DNA found living matter to be the best way to perpetuate itself. Why did nature settle upon this solution?

Perhaps in answering this question--why living matter perpetuates DNA best--we can get closer to a definition of life. Perhaps every characteristic we think of as "life" is nothing more than the orchestrated chemical processes which are assembled for the singular purpose of DNA perpetuation. Is this sufficient to distinguish living matter from Prebe's computer example?