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... Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Meteorites Also Transport Organic Payloads Excerpts from the Abstract of a paper printed in Nature: "Much effort has been directed to analyses of organic compounds in carbonaceous chondrites because of their implications for orgainc chemical evolution and the origin of life. We have determined the isotopic composition of hydrogen, nitrogen and carbon in amino acid and monocarboxylic extracts from the Murchison meteorite. .. .. . "These results confirm the extraterrestrial origin of both classes of compounds, and provide the first evidence suggesting a direct relationship between the massive organo-synthesis occurring in interstellar clouds and the presence of pre-biotic compounds in primitive planetary bodies." (Epstein, S., et al; "Unusual Stable Isotope Ratios in Amino Acid and Carboxylic Acid Extracts ... Science Frontiers ONLINE No. 52: Jul-Aug 1987 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Meteorites Also Transport Organic Payloads Excerpts from the Abstract of a paper printed in Nature: "Much effort has been directed to analyses of organic compounds in carbonaceous chondrites because of their implications for orgainc chemical evolution and the origin of life. We have determined the isotopic composition of hydrogen, nitrogen and carbon in amino acid and monocarboxylic extracts from the Murchison meteorite. .. .. . "These results confirm the extraterrestrial origin of both classes of compounds, and provide the first evidence suggesting a direct relationship between the massive organo-synthesis occurring in interstellar clouds and the presence of pre-biotic compounds in primitive planetary bodies." (Epstein, ...
Terms matched: 2 - Score: 227 - 15 May 2017 - URL: /sf052/sf052a05.htm
... In nonlife (if such a state really exists), amino-acid molecules are right- and lefthanded in equal numbers -- as least this has been the theory up until now. Amino acids are found in substances we assume are non-life or of abiotic origin. In fact, amino acids are present in meteorites, often in substantial amounts. They are profuse in Australia's Murchison meteorite, a carbonaceous chondrite. However, analysis of the Murchison's amino acids indicates that there are slightly more (7 -9 %) left-handed than right-handed amino acids present. This extraterrestrial handedness is of great import to both cosmologists and biologists, because the carbonaceous chondrites are thought to have formed 4.5 billion years ago -- long before life on earth ... can determine, only left-handed amino acids are incorporated into proteins. In nonlife (if such a state really exists), amino-acid molecules are right- and lefthanded in equal numbers -- as least this has been the theory up until now. Amino acids are found in substances we assume are non-life or of abiotic origin. In fact, amino acids are present in meteorites, often in substantial amounts. They are profuse in Australia's Murchison meteorite, a carbonaceous chondrite. However, analysis of the Murchison's amino acids indicates that there are slightly more (7 -9 %) left-handed than right-handed amino acids present. This extraterrestrial handedness is of great import to both cosmologists and biologists, because the carbonaceous chondrites are thought to have ...
Terms matched: 2 - Score: 224 - 15 May 2017 - URL: /sf111/sf111p03.htm
... amino acid molecules are levorotatory rather than the mirror-image dextrorotatory versions. Because humans "expect" symmetry in nature, it is taken for granted that everything else in the universe is split equally between leftand right-handed molecules. Earth life is just a fluke -- or is it? On September 28, 1969, organic-rich stones fell in Victoria, Australia. This was the Murchison meteorite, and it may carry a message. Over a decade ago, M.H . Engel and B. Nagy reported that the organic molecules in the Murchison meteorite were not split 50:50 between left- and right-handed versions. So contrary to expectations was this finding that most scientists assumed that the analysis was contaminated by terrestrial organic molecules. Now, M.H . ... and S.A . Macko have refined the analytical techniques and apparently avoided any taint of contamination. Their conclusion: the Murchison amino acids still lean to the left. From all this arise several intriguing possibilities: Life on earth started split evenly between left- and right-handed amino acids, but was nudged to the left by the influx of organic-laden meteorites like the Murchison. Terrestrial life actually originated elsewhere in the universe where much matter is left-handed, including life, if it exists there. In other words, our philosophical expectation of symmetry in the universe-as-a -whole is incorrect. The universe on the average is evenly split between left- and right-handed molecules, but there are "islands" or "pockets" which are left- ...
Terms matched: 2 - Score: 220 - 15 May 2017 - URL: /sf115/sf115p03.htm
... " to surround themselves with bags of lipids. (Bag of lipids = a membrane.) (Nisbet, E.G .; "RNA and Hot-Water Springs," Nature, 322:206, 1986.) It just so happens that D.W . Deamer, University of California, Davis, has now found that the 4.5 -billion-year-old Murchison meteorite from Australia contains lipid-like organic chemicals that can self-assemble into membrane-like films. His paper was presented before the International Society for the Study of Origins of Life. (Raloff, J.; "Clues to Life's Cellular Origins," Science News, 130:71, 1986.) Comment. Strange that the earth should be "tailor-made ... for biochemical operations and that outer space teems with meteorites transporting other ingredients of life-synthesis. That the earth's crust and deep soil are conducive to life is apparent in recent work done sponsored by DuPont and the Department of Energy. This effort has found that life is abundant at least 850 feet below the surface -- a realm hardly suspected to harbor life. "' There is life down there, and it is very diverse,' says Carl Fliermans of Dupont's Savannah River Laboratory in Aiken, S.C . The numbers are high enough to affect the chemistry of the environment: Some of the samples contained as many as 10 million organisms per gram of soil. But even more surprising than the high concentrations is the diversity of the microorganisms, according to David ...
Terms matched: 2 - Score: 160 - 15 May 2017 - URL: /sf047/sf047p11.htm
