Donald Savage
Headquarters, Washington Dec. 19, 2001
(Phone: 202/358-1547)

Kathleen Burton
Ames Research Center, Moffett Field, Calif.
(Phone: 650/604-1731)

RELEASE: 01-253

NASA SCIENTIST FINDS SOME METEORITES NOT SUGAR-FREE

A discovery by a NASA scientist of sugar and several 
related organic compounds in two carbonaceous meteorites 
provides the first evidence that another fundamental building 
block of life on Earth may have come from outer space. A 
carbonaceous meteorite contains carbon as one of its 
important constituents.

Previously, researchers had found in meteorites other 
organic, carbon-based compounds that play major roles in life 
on Earth, such as amino acids and carboxylic acids, but no 
sugars. The new research is reported in a paper, 
"Carbonaceous Meteorites as a Source of Sugar-related Organic 
Compounds for the Early Earth," by Dr. George Cooper and co-
workers at NASA's Ames Research Center, Moffett Field, Calif. 
The work is published in the Dec. 20 issue of Nature.

"Finding these compounds greatly adds to our understanding of 
what organic materials could have been present on Earth 
before life began," Cooper said. "Sugar chemistry appears to 
be involved in life as far back as our records go." Recent 
research using ratios of carbon isotopes have pushed the 
origin of life on Earth to as far back as 3.8 billion years, 
he said. An isotope is one of two or more atoms whose nuclei 
have the same number of protons but different numbers of 
neutrons.

Scientists have long believed meteorites and comets played a 
role in the origin of life. Raining down on Earth during the 
heavy bombardment period some 3.8 billion to 4.5 billion 
years ago, they brought with them the materials that may have 
been critical for life, such as oxygen, sulfur, hydrogen and 
nitrogen. Sugars and the closely related compounds discovered 
by Cooper, collectively called "polyols," are critical to all 
known life forms. They act as components of the nucleic acids 
RNA and DNA, constituents of cell membranes and cellular 
energy sources.

"This discovery shows that it's highly likely organic 
synthesis critical to life has gone on throughout the 
universe," said Kenneth A. Souza, acting director of 
astrobiology and space research at Ames. "Then, on Earth, 
since the other critical elements were in place, life could 
blossom."

Cooper identified a small sugar called "dihydroxyacetone" and 
several sugar-like substances, known as sugar acids and sugar 
alcohols, in his study of the Murchison and Murray 
meteorites. All these are important for life today. He also 
found one sugar alcohol, glycerol (also known as glycerin), 
that is used by all contemporary cells to build cell walls. 
In addition, Cooper discovered preliminary evidence of other 
compounds that may contain larger sugars critical in cellular 
metabolism, such as glucose. 

There still are many unknowns though about the chemistry that 
existed before the origin of life on Earth, according to 
Cooper. "What we found could just be interesting space 
chemistry, and polyols could be just relatives of the 
compounds that actually gave rise to early life." More 
research on the meteorites is essential to determine the 
significance of these findings, he concluded. 

The Murchison meteorite, found in Australia in 1969, is a 
famous example of a carbonaceous meteorite that contains 
numerous amino acids and a variety of other organic compounds 
that are thought to have played a role in the origin of life. 
The Murray meteorite, which fell to Earth in 1950, is similar 
to Murchison in its organic content.

Related information about the Cooper paper in Nature can be found at:

http://www.nature.com

Further information about the Murchison meteorite is available at: 

http://www.touchanotherworld.com/CurrentPhoto/CPcarbonaceous.htm

NASA's Exobiology Program provided funding for the research.

-end-

Oryginal:
ftp://ftp.hq.nasa.gov/pub/pao/pressrel/2001/01-253.txt

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