Word: amino
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Dates: during 1970-1979
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...life begin? Cyril Ponnamperuma, 55, a Ceylon-born geochemist at the University of Maryland, has been seeking answers to this question for much of his career. He has created precursors of life in laboratory simulations of the earth's primitive atmosphere and while with NASA in 1970, identified amino acids (the building blocks of protein) in the Murchison meteorite, which had fallen in Australia a year earlier. Last week, at a meeting of the American Chemical Society in Washington, Ponnamperuma presented three new pieces of evidence that the processes leading to the formation of life can take place...
...Analyzing material from two meteorites found in Antarctica, where they had been frozen in ice for 200,000 years, Ponnamperuma and his colleagues discovered many amino acids, about half of them different from any that are found in living organisms. Two facts convinced him that the acids are, in his words, "extraterrestrial and pre-biotic": 1) Unlike the Murchison meteorite, which had been contaminated by earthly organic matter after it fell, the Antarctic meteorites were pristine, containing only the amino acids they brought to the earth from space...
...When polarized light was passed through solutions of water and some of the amino acids, it was deflected to the right. "In all the '20 amino acids we know of on earth," says Ponnamperuma, "the polarized light turns to the left." But, he adds, "In all the pre-biotic experiments conducted in our laboratory, we got both lefthanded and righthanded amino acids." His conclusion: the amino acids are not due to terrestrial contamination, but to pre-life forms that evolved somewhere in space...
...tracking antenna in Spam and the Ames control center. Still, enough information was retrieved to confirm that the temperature at Titan's cloud tops was a frigid -200° C (-328° F). That seemed to rule out surface temperatures warm enough to allow the formation of amino acids, the building blocks of life. But scientists were withholding final judgment until the Voyagers get their closeup look at Titan...
Proposed in 1969 by Pathologist Kilmer McCully, then of Harvard, this thesis also implicates diet, but the villain is protein. Methionine, an amino acid, is broken down by the body into homocysteine, a chemical that promotes atherosclerosis (or the buildup of plaque in the arteries) in lab animals. According to the theory, it is converted by vitamin B6 into an innocuous byproduct, but if there is a deficiency of B6, homocysteine piles up in the blood and causes atherosclerosis. In the view of the theory's proponents, Americans are vulnerable to heart disease because the protective vitamin, which...