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  • Urea  (3)
  • Aminoacylnucleotides  (2)
  • LUNAR AND PLANETARY EXPLORATION  (2)
  • 1
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    The search for organic substances and inorganic volatile compounds in the surface of Mars (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: A total of four Martian samples, one surface and one subsurface sample at each of the two Viking landing sites, Chryse Planitia and Utopia Planitia, have been analyzed for organic compounds by a gas chromatograph-mass spectrometer. In none of these experiments could organic material of Martian origin be detected at detection limits generally of the order of parts per billion and for a few substances closer to parts per million. The evolution of water and carbon dioxide, but not of other inorganic gases, was observed upon heating the sample to temperatures of up to 500 C. The absence of organic compounds seems to preclude their production on the planet at rates that exceed the rate of their destruction. It also makes it unlikely that living systems that behave in a manner similar to terrestrial biota exist, at least at the two Viking landing sites.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 82; Sept. 30
    Format: text
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    NASA TECHNICAL REPORTS
  • 2
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    Search for organic and volatile inorganic compounds in two surface samples from the Chryse Planitia region of Mars (1976)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: Two surface samples collected from the Chryse Planitia region of Mars were heated to temperatures up to 500 C, and the volatiles that they evolved were analyzed with a gas chromatograph-mass spectrometer. Only water and carbon dioxide were detected. This implies that organic compounds have not accumulated to the extent that individual components could be detected at levels of a few parts per billion by weight in the samples. Proposed mechanisms for the accumulation and destruction of organic compounds are discussed in the light of this limit.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Oct. 1
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
    Electronic Resource
    Electronic Resource
    Prebiotic peptide-formation in the solid state (1975)
    Springer
    Journal of molecular evolution 5 (1975), S. 57-73 
    Details
    ISSN: 1432-1432
    Keywords: Prebiotic Activation ; Peptides ; Aminoacylnucleotides ; Nucleoside Phosphoramidates ; Amino Acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The reactions of benzoate ion and of glycine with adenosine 5′-phosphorimidazolide have been investigated. Benzoate reacts first to give the anhydride, benzoyl-adenylate, which, in the presence of excess imidazole, reacts further to give the 2′- and 3′-esters of adenosine 5′-phosphate. Glycine also first attacks the imidazolide to give an anhydride, but this compound may react further either to give 2′- and 3′-esters or to form peptides, depending on the reaction conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01732014
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Amino acid activation with adenosine 5′-phosphorimidazolide (1978)
    Springer
    Journal of molecular evolution 11 (1978), S. 9-16 
    Details
    ISSN: 1432-1432
    Keywords: Aminoacylnucleotides ; Imidazole catalysis ; Amino acid activation ; Nucleoside phosphoramidates ; Prebiotic chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Amino acids are activated by reaction with adenosine 5′-phosphorimidazolide in aqueous imidazole buffers. If adenosine 5′-(O-methylphosphate), an analogue of the 3′-terminus of t-RNA is present, 2′(3′)-O-aminoacyladenosine 5′-(O-methylphosphate) is formed. Fifteen percent of this compound accumulated at pH 5.8, but less was formed at higher pHs. The highest efficiency of utilization of ImpA attained in our experiments was about 24%. Analogous reactions occured with several other amino acids, including a number that have functional side-chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01768020
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Polyphosphate and trimetaphosphate formation under potentially prebiotic conditions (1972)
    Springer
    Journal of molecular evolution 1 (1972), S. 241-248 
    Details
    ISSN: 1432-1432
    Keywords: Urea ; Ammonium Dihydrogen Phosphate ; Nucleoside ; Prebiotic ; Polyphosphate ; Trimetaphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When ammonium dihydrogen phosphate is heated with urea to temperatures in the range 85–100°C, it polymerizes almost quantitatively to give polyphosphates containing, on the average, more than ten (PO3) residues. Similar experiments carried out at 72°C give polyphosphate in more than 60% yield. If a nucleoside (thymidine or 3′-deoxythymidine) is added to the reaction mixture, up to 23% of trimetaphosphate can be obtained at 100°C. The prebiotic significance of these reactions is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01660243
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  • 6
    Electronic Resource
    Electronic Resource
    Further studies of urea-catalyzed phosphorylation reactions (1973)
    Springer
    Journal of molecular evolution 2 (1973), S. 231-234 
    Details
    ISSN: 1432-1432
    Keywords: Phosphorylation ; Nucleotides ; Nucleoside Polyphosphates ; Oligonucleotides ; Urea ; Prebiotic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analyzed the products formed when mixtures of a nucleoside and ammonium dihydrogen phosphate are heated with an excess of urea. If there is more phosphate than nucleoside in the mixture, compounds containing pyrophosphate bonds are obtained. If uridine, as nucleoside, is in excess over phosphate, di- and oligonucleotides are formed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01654004
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of Mg2+ and Ca2+ on urea-catalyzed phosphorylation reactions (1973)
    Springer
    Journal of molecular evolution 2 (1973), S. 251-262 
    Details
    ISSN: 1432-1432
    Keywords: Prebiotic Phosphorylation ; Urea ; Struvite ; Ammonium phosphate ; Hydroxylapatite ; Nucleotide ; Pyrophosphate ; Esterification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When struvite (MgNH4PO4 ⋅ 6H2O) is heated with urea at 65–100°C, inorganic pyrophosphate is formed in good yield. Under similar conditions pyro-phosphate is formed much more slowly from ammonium phosphate or hydroxylapatite. The major products formed by the reaction of nucleotides with urea and either ammonium phosphate or hydroxylapatite are derivatives phosphorylated on the 2′ or 3′ position. With struvite, on the other hand, the main reaction is pyrophosphate bond formation. Yields of up to 25% of uridine diphosphate can be obtained at temperatures as low as 65°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01654094
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