Sinduja Marx's List: General_astrobio_articles

• Carbonyl Sulfide Forms Peptide Bonds
• how did the first amino acids form   the first peptides?
• the missing link is a chemical component of volcanic   gas known as carbonyl sulfide.
• In their report, the scientists demonstrate that the gas can bring   about a vigorous chemical reaction that forms peptides under mild   aqueous conditions.

  • "mild aqueous"
    How much water needed?
    i.e. tonnes of water essential to kick start life?
    must me be a major misconception then, that major amounts of water is quintessential to life.
• Life—What We Know, and What We Don't
• interesting perhaps because we know   approximately when it occurred, but we do not know how it occurred.
• The earliest fossils scientists have found are stromatolites—large   clumps of cyanobacteria that grew in abundance in the ancient world   over 3.5 billion years ago in what is now western Australia.
• cyanobacteria
• what came before the stromatolites?
• Research on the origins of life has suggested the notion of an ancient   RNA world
• what is chemically feasible and what could have occurred on the   prebiotic earth.
• One possibility, which was suggested in the 1920s by the Russian   scientist A.I. Oparin, is that life emerged in its most primitive   forms from minerals, metals, and the elements carbon, hydrogen,   oxygen, and nitrogen, which were combined into amino acids, nucleotides,   and the other the building blocks of life under the violent energy   of lightning, solar radiation, comet impacts, and volcanic events   that were present.
• In 1953, this theory was given a boost when a paper was published   in Science by Stanley L. Miller, who is Professor Emeritus   at the University of California, San Diego. In the paper, Miller   described an experiment he devised with Harold C. Urey—now   called the Miller and Urey experiment—that gave experimental   underpinnings to Oparin's ideas.
• In the experiment, Miller boiled H₂O, CH₄,H₂, and NH₃ gases in a   glass apparatus containing a pair of tungsten electrodes. He subjected   the chemicals to an electric discharge, intended to simulate conditions   on the early Earth, and he collected and analyzed the molecules   that formed—which included the amino acids alanine, glycine,   and a few others. In the years since, several other investigators   have expanded on the Miller–Urey experiment to demonstrate   the formation and chemistry of many of the common biological amino   acids, sugars, and nucleotides. Orgel, who is a long-time investigator   in the field, has done pioneering research on the prebiotic chemistry   of nucleotides.
• Next, the team   plans to examine carbonyl sulfide's reactive properties further   and see if the gas can bring about other chemical reactions that   are relevant to prebiotic chemistry.
• The article, "Carbonyl Sulfide–Mediated Prebiotic Formation   of Peptides" by Luke Leman, Leslie Orgel, and M. Reza Ghadiri,   appears in the October 8, 2004 issue of the journal Science.   See: http://www.sciencemag.org.

14 more annotations...

• Outline
  1 - Carbonyl sulfide forms peptide bonds
  ~present in deep sea vent emissions and volcanic gasses
  ~gas+mild aqueous conditions=peptides from amino acids
  2 - Origins of life: the known, and the unknown
  ~when life occurred?
  ~3.5 billion years ago, cyanobacteria = stromatolites
  ~before stromatolites?
  ~an RNA world
  ~how an RNA world came into existence?
  ~Miller and Urey experiment (UCSD) - Sinduja Marx on 2010-06-16