Ceilidh

Michael Zey
futurist3000@aol.com

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Authors:                  Sharon Begley

Pagination:               B.1

ISSN:                     00999660

Subject Terms:            Molecular biology

Classification Codes:     8305: Professional services not elsewhere classified


Abstract:

"Creating a cell from scratch is probably at least 10 years away, but it
is going to happen," says Mark Bedau of Reed College, Portland, Ore. "We're
in for some very interesting, very profound new ways of thinking about
what life is, and about where you draw the boundary between life and nonlife."

"As they form, the vesicles capture a polymerase enzyme that strings together
small molecular building blocks into more complicated molecules," says
Prof. [David Deamer]. "The vesicles take in molecules from the outside,
and the polymerase uses them as nutrients and as an energy source to synthesize
RNA," a cousin of DNA.

If researchers manage to create living cells from scratch, their mastery
of the machinery of life could blur the line between alive and not-alive.
Combining the traits of artificial cells with nanotechnology, Dr. [Steen
Rasmussen] and colleagues wrote in a recent issue of Science, could produce
machines that "would literally form the basis of a living technology possessing
powerful capabilities and raising important social and ethical" questions.
Adds Prof. Bedau, "It will be crossing a threshold, enabling technologies
we can't even imagine now."
Copyright (c) 2004, Dow Jones & Company Inc. Reproduced with permission
of copyright owner. Further reproduction or distribution is prohibited
without permission.

Full Text:

AS ANY GEEK who ever soldered together a circuit board from off-the- shelf
parts can testify, if you truly want to understand how something works,
you need to build it yourself.

That approach doesn't raise any eyebrows when applied to gizmos and gadgets,
but now a loosely organized band of scientists is extending it in an audacious
way. In hopes of answering the age-old question "what is life?" they are
trying to assemble -- from off-the-shelf, nonliving molecules -- a living
cell.

"Creating a cell from scratch is probably at least 10 years away, but it
is going to happen," says Mark Bedau of Reed College, Portland, Ore. "We're
in for some very interesting, very profound new ways of thinking about
what life is, and about where you draw the boundary between life and nonlife."

One of the deepest mysteries in biology is how molecules that are no more
alive than the tip of a pencil can form a reproducing, metabolizing, evolving
organism. If you plop a droplet of any of the molecules that make up living
cells (fats, amino acids, water, DNA, other organic molecules) onto a glass
slide, it just sits there. No one would mistake it for a living thing.
Yet when the right ingredients assemble in the right proportions, the result
comes alive, as it did on Earth some 3.8 billion years ago.

The transformation is so profound that most scientists until the 19th century
believed in the theory called vitalism. This holds that living things possess
a mysterious "vital spark" that endows them with life, and that life cannot
be explained by mere chemistry and physics. But today, harnessing no more
than thermodynamics, electromagnetism and chemistry, scientists are taking
steps toward creating a living cell.

THE FIRST STEP is to separate the would-be cell from the outside world,
and this turns out to be startlingly simple. Several researchers have created
little self-replicating vesicles, minuscule bubbles much like the membranes
around living cells. In a special mixture of oil and water, Luigi Luisi
of the Swiss Federal Institute of Technology, Zurich, has found, membranes
form spontaneously, grow by incorporating small molecules from the outside
world, and reproduce by pinching themselves in two, like amoebas.

Dr. Luisi's vesicles fulfill two of the main requirements for life, growing
and reproducing. In addition, says David Deamer of the University of California,
Santa Cruz, a living cell must transform raw materials and energy into
more of itself (metabolize), and also evolve. Although no one has gotten
a single vesicle to carry out all of these reactions, Prof. Deamer and
his colleague Pierre-Alain Monnard are coming close.

"As they form, the vesicles capture a polymerase enzyme that strings together
small molecular building blocks into more complicated molecules," says
Prof. Deamer. "The vesicles take in molecules from the outside, and the
polymerase uses them as nutrients and as an energy source to synthesize
RNA," a cousin of DNA.

Other groups of scientists have gotten simple amino acids to link together
into proteins, like beads linking into a biological necklace. The reaction
occurs on the surface of the vesicle, which somehow jump- starts the assembly.
The vesicles created in the lab are not just dumb containers; they support
biological reactions.

Last fall, molecular biologist Jack Szostak of Massachusetts General Hospital,
Boston, and colleagues reported that common clay particles have an unsuspected
talent. They can speed up the conversion of little clusters of molecules
into vesicles, making the formation of a cell membrane even easier. Inside
the vesicle, the clay particles grab hold of short bits of RNA and assemble
them into a long strand. Voila: a little sphere containing genetic material
able to grow and copy itself.

THE MISSING ingredient in this cell wannabe is metabolism, but Steen Rasmussen
of Los Alamos National Lab thinks he can provide it. He and Liaohai Chen
of Argonne National Lab have designed a microscopic container with metabolic
molecules and genes whose electrical properties drive metabolic reactions.
The scientists have demonstrated experimentally that this micrometabolism
can produce exactly the molecules the container is made of (so the system
would be able to grow).

"All the pieces are there -- self-assembling container, genes and metabolism
that captures energy from the outside world," says Dr. Rasmussen. "The
question is, how do we get it to reproduce? If we do, then most people
would say it is alive."

If researchers manage to create living cells from scratch, their mastery
of the machinery of life could blur the line between alive and not-alive.
Combining the traits of artificial cells with nanotechnology, Dr. Rasmussen
and colleagues wrote in a recent issue of Science, could produce machines
that "would literally form the basis of a living technology possessing
powerful capabilities and raising important social and ethical" questions.
Adds Prof. Bedau, "It will be crossing a threshold, enabling technologies
we can't even imagine now."

Scientists are close enough to creating life in the lab that it is time
to start a public debate about what that would mean -- for traditional
views of the sanctity of life as well as for whether the creators will
be able to control their creations.

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