1/31/01 9:55 a.m.
The Lumber of Life?
A new NASA report.

By John Farrell, a writer and producer of videos for the Institute for Education & Research at Beth Israel Deaconess Medical Center & Harvard Medical School

new report by a team of researchers working for NASA and University of California at Santa Cruz gives a boost to the possibility that life on Earth was jump-started by cosmic debris — meteors and comets.

Reporting this week in the Proceedings of the National Academy of Sciences, Louis Allamandola of NASA's Ames Research Center and David Deamer, professor of Chemistry at Santa Cruz (among others) reveal how they duplicated the harsh conditions of interstellar space: Creating a vacuum and coaxing artificial cell membranes into existence by irradiating organic compounds with ultraviolet light.

Which compounds? Ices made of water, methanol, ammonia, and carbon monoxide, according to the BBC report on the team's findings. Irradiating them produced solid matter. The scientists then immersed these in water and watched them spontaneously create soap-bubble lookalikes, membranous forms which included inner and outer layers.

These artificial cell membranes could act as primitive cell walls, according to Deamer. He told Reuters, "This wall is semi-permeable. All membranes are semi-permeable, so that things like water and oxygen get in and out very easily. This is what life requires — it needs to have an inside that it not totally shut off from the outside."

He added that compounds found in dust from meteorites carried to Earth were discovered to "self-assemble" into soapy, water-resistant bubbles.

According to Allamandola: "Scientists believe the molecules needed to make a cell's membrane, and thus the origin of life, are all over space." He added this discovery implies "that life could be everywhere in the universe."

What isn't yet in evidence everywhere in the universe are planets like the Earth with stable stars like the Sun which would allow such molecules the time they need to thrive and produce complex life.

Still, such vesicles as created by Deamer and Allamandola show the prevalence of the building blocks life would need and show how they might have helped to protect early self-replicating molecules as they evolved into primitive life on Earth.

Dr. Jason Dworkin of California's SETI Institute (Search for Extra-Terrestrial Intelligence) commented: "All life as we know it on Earth uses membrane structures to separate and protect the chemistry involved in the life process from the outside."

"Membranes are like a house. Maybe these molecules were just the raw lumber lying around that allowed origin-of-life chemicals to move in and set up housekeeping or construct their own house."

The idea that life on Earth may have been caused or aided in its origin by interstellar debris is not new. Astronomer Fred Hoyle and DNA co-discoverer Francis Crick long ago suggested it was more realistic to accept an outside source for life's origin on Earth rather than the conventional view held by many evolutionary scientists that life sprung from the primordial soup.

On the other hand, evolutionary scientists have not been idle. A few weeks back, for example, the New York Times reported on a team that analyzed the world's oldest rocks and found water molecules, suggesting that the Earth became covered in water (soup?) much earlier in its history than had previously been believed.

Stay tuned. Deamer told Reuters the next step for the researchers is to find out if their bubbles can support some cell-life activities. "We are trying on purpose to put things like DNA and RNA inside the vesicles." He added, "In a sense we are trying to make, not an artificial form of life because we are nowhere near this, but a model of what would have led to early life."