| Adsorption of Adenine, Cytosine, Thymine, and Uracil on Sulfide-Modified Montmorillonite: FT-IR, Mössbauer and EPR Spectroscopy and X-Ray Diffractometry Studies. | |
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MedLine Citation:
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PMID: 21717172 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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In the present work the interactions of nucleic acid bases with and adsorption on clays were studied at two pHs (2.00, 7.00) using different techniques. As shown by Mössbauer and EPR spectroscopies and X-ray diffractometry, the most important finding of this work is that nucleic acid bases penetrate into the interlayer of the clays and oxidize Fe(2+) to Fe(3+), thus, this interaction cannot be regarded as a simple physical adsorption. For the two pHs the order of the adsorption of nucleic acid bases on the clays was: adenine ≈ cytosine > thymine > uracil. The adsorption of adenine and cytosine on clays increased with decreasing of the pH. For unaltered montmorillonite this result could be explained by electrostatic forces between adenine/cytosine positively charged and clay negatively charged. However for montmorillonite modified with Na(2)S, probably van der Waals forces also play an important role since both adenine/cytosine and clay were positively charged. FT-IR spectra showed that the interaction between nucleic acid bases and clays was through NH(+) or NH (2) (+) groups. X-ray diffractograms showed that nucleic acid bases adsorbed on clays were distributed into the interlayer surface, edge sites and external surface functional groups (aluminol, silanol) EPR spectra showed that the intensity of the line g ≈ 2 increased probably because the oxidation of Fe(2+) to Fe(3+) by nucleic acid bases and intensity of the line g = 4.1 increased due to the interaction of Fe(3+) with nucleic acid bases. Mössbauer spectra showed a large decreased on the Fe(2+) doublet area of the clays due to the reaction of nucleic acid bases with Fe(2+). |
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Authors:
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Cristine E A Carneiro; Graciele Berndt; Ivan G de Souza Junior; Cláudio M D de Souza; Andrea Paesano; Antonio C S da Costa; Eduardo di Mauro; Henrique de Santana; Cássia T B V Zaia; Dimas A M Zaia |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-6-30 |
Journal Detail:
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Title: Origins of life and evolution of the biosphere : the journal of the International Society for the Study of the Origin of Life Volume: - ISSN: 1573-0875 ISO Abbreviation: - Publication Date: 2011 Jun |
Date Detail:
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Created Date: 2011-6-30 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8610391 Medline TA: Orig Life Evol Biosph Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Laboratório de Química Prebiótica, Departamento de Química-CCE, Universidade Estadual de Londrina, 86051-990, Londrina, PR, Brazil. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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