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  • 2020-2024
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  • 2005-2009
  • 1975-1979  (4)
  • 1920-1924
  • 1900-1904
  • Polymerization
  • 1
    Electronic Resource
    Electronic Resource
    Cyanamide mediated syntheses under plausible primitive earth conditions (1977)
    Springer
    Journal of molecular evolution 10 (1977), S. 193-209 
    Details
    ISSN: 1432-1432
    Keywords: Prebiotic ; Polymerization ; Deoxythymidine oligonucleotides ; Deoxythymidine 5′-triphosphate ; Deoxythymidine 5′-monophosphate ; 4-amino-5-imidazolecarboxamide ; Cyanamide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When an aqueous solution (pH 7.0) of3H deoxythymidine 5′-triphosphate, deoxythymidine 5′-phosphate, 4-amino-5-imidazolecarboxamide, cyanamide and ammonium chloride was dried and heated at 60°C for 18 h, oligomers were obtained in a yield of approximately 80%. After the chemical degradation of any pyrophosphate bonds present in these oligomers, linear polynucleotides of up to 7–8 units in length were isolated by DEAE cellulose column chromatography and identified by enzymatic digestion procedures. The di- and trinucleotide fractions were degraded 87% and 100% by snake venom phosphodiesterase and 39% and 9% by spleen phosphodiesterase. This synthesis of deoxythymidine oligonucleotides was conducted under potentially prebiotic conditions and may offer a possible method for the synthesis of deoxyoligonucleotides on the primitive Earth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01764595
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  • 2
    Electronic Resource
    Electronic Resource
    Cyanamide mediated syntheses under plausible primitive earth conditions (1977)
    Springer
    Journal of molecular evolution 10 (1977), S. 183-192 
    Details
    ISSN: 1432-1432
    Keywords: Prebiotic ; Polymerization ; Deoxythymidine oligonucleotides ; Deoxythymidine 5′-monophosphate ; P1, P2-dideoxythymidine 5′-pyrophosphate ; 4-amino-5-imidazolecarboxamide ; Cyanamide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When an aqueous solution (pH 7.0) of deoxythymidine 5′-phosphate, 4-amino-5-imidazolecarboxamide and cyanamide was dried and heated for 18 h at 60°C, P1, P2-dideoxythymidine 5′-pyrophosphate (I) was formed in a 58% yield. Oligonucleotides were not detected in the reaction product. Under conditions employed in the above reaction, (I) was shown to be stable. In prebiotic polymerization reactions employing deoxythymidine 5′-triphosphate as the polymerizing species, (I) could therefore function as a primer and minimize the formation of cyclic nucleotides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01764594
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of barbiturates on ultrastructure and polymerization of microtubules in vitro (1975)
    Springer
    Cell & tissue research 162 (1975), S. 35-47 
    Details
    ISSN: 1432-0878
    Keywords: Microtubules ; Barbiturates ; Axonal transport ; Polymerization ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Barbiturates were examined for in vitro effects on ultrastructure of the frog sciatic system and polymerization of microtubules (MT) in a brain supernatant. Exposure for 5–17 h to 2.0 mM barbiturates caused a considerable loss of MT in ganglionic cell bodies and sciatic axons. This was mostly followed by a proliferation of 10 nm filaments. Under similar conditions treatment with 1 mM NaCN or 0.1 mM 2,4-DNP did not change the number or ultrastructure of MT and filaments. Eight barbiturates, varying in binding ratios to serum albumin and partition coefficients, were tested for effects on polymerization of MT using viscometry. Inhibitory effects were found which correlated with their reported ability to bind to albumin and brain fractions. Dimethylsulphoxide and ethanol were used as solvents for some of the barbiturates. These solvents at 1% had stabilizing effects on MT. The present results are discussed in relation to previous findings of inhibition of rapid axonal transport in vitro in the frog sciatic system by barbiturates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223260
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Isomerization Polymerization of Lactams (1975)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 14 (1975), S. 43-51 
    Details
    ISSN: 0570-0833
    Keywords: Isomerization polymerization ; Polymerization ; Lactams ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isomerization polymerization affords a macromolecule whose repeating unit is derived from an isomer of the original monomer. Thus hexa- and heptacyclic β-carboxymethyllactams yield polymers containing glutarimide units, whereas penta- and hexacyclic β-carboxylactams furnish polymers containing succinimide units. Some dimethyl derivatives of β-carboxylactams isomerize or rearrange, and 5-oxopyrrolidine-3-acetic acid does not react at all. These observations can be explained in terms of a bicyclic intermediate.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.197500431
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    Paper (German National Licenses)
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