National Repository of Grey Literature 11 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Utilization of Catalytic Hydrogen Evolution in Electrochemical Analysis of Nucleic Acids
Fojta, Miroslav ; Daňhel, Aleš ; Špaček, Jan ; Havran, Luděk ; Šebest, Peter ; Orság, Petr ; Pivoňková, Hana ; Vosáhlová, J. ; Schwarzová-Pecková, K.
Catalysis of hydrogen evolution (CHE) at mercury in the presence of proteins was discoverd shortly after the introduction of polarography. In contrast, unmodified nucleic acids have not been reported to produce distinct signals due to the CHE to date. Chemically modified nucleic acids bearing certain extrinsic groups produce analytically useful signals due to hydrogen evloution catalyzed by the respective modifications. These species include (a) transition metal complexes, and (b) non-metal catalytically active organic moieties. In addition, the CHE has been reported to be invoved in guanine reduction process at the mercury-based electrodes.
2D Condensation of 5-Fluorocytosine in Different Electrolytes
Fojt, Lukáš ; Fojta, Miroslav
Two-dimensional (2D) condensation and adsorption of 5-fluorocytosine on hanging mercury drop electrode in differnt electrolytes was investigated. We have used different sodium halide salts as basic electrolytes. The influence of electrolytes composition was displayed using differential capacitance measurements. Effects of ions present in used electolytes solution was remarkable. We observed huge change in 2D condensed layers in dependence on ions type.
Effect of Thymine and Cytosine Nucleobase Sequence on the Two-Dimensional Condensation of Pyrimidine Oligodeoxynucleotides at Mercury Surface
Hasoň, Stanislav ; Fojta, Miroslav
The aim of this contribution is study the effect of thymine and cytosine nucleobase composition (different lengths and/or repeat segments of either thymine or cytosine units or their combinations) within a set of the oligodeoxynucleotide (ODN) chains on the two-dimensional of homo- and hetero-pyrimidine ODNs at mercury electrode surface. It was shown that pyrimidine ODNs containing eight and more pyrimidine nucleobases can form, at negatively charged Hg surface (around1.32 V vs. Ag/AgCl), two different 2D condensed films characterized by the differential capacitances of about 9.4 (I-2D) and 7.6 mu F cm(-2) (II2D) respectively.
Limitations and Possibilities of Nanostructurized Silver Amalgam
Daňhel, Aleš ; Šebest, Peter ; Vidláková, Pavlína ; Ligmajer, Filip
Variability of silver amalgam offers a row of opportunities for its application in electrochemical and spectroelectrochemical methods, thanks to its chemical, mechanical, electrochemical and spectrometric properties. This work briefly revews preparation possibilities and limitations of nanostructurized crystalas and nanopartices pf silver amalgam at different forms of carbon metals (Ag, Au, Pt) and transparent materials (ITO, FTO). These detection sysytems are in the scope of ongoing systematics research with the potential to indevelopment of novel working (micro)electrodes and spectroelectrochemical cells, potentially utilizable in modern (bio)analytical applictions.
Reduction of the DNA at a Pyrolytic Graphite Electrode:Opening of the Second Half of the Potential Window
Špaček, Jan ; Daňhel, Aleš ; Hasoň, Stanislav ; Hejduková, M. ; Fojta, Miroslav
The pyrolytic graphite electrode (PGE) can be used at highly negative potentials, providing reduction signals known from mercury-based electrodes. Use of the negative part of the potential window more than doubled the number of analytically useful signals provided by unlabelled DNA on PGE. It enables selective analysis of all canonical DNA bases,5-methylcytosine and uracil It also allows for distinction of overlapping signals cathodic polarization can selectively ´switch off´ DNA anodic signals and rice versa. Newly observed signals corresponding to oxidation of reduced bases and reduction of oxidized bases are also described.
Electrochemical Deposition of Silver Amalgam Particles on Pyrolitic Graphite Electrode
Šebest, Peter ; Havranová-Vidláková, Pavlína ; Ligmajer, Filip ; Fojta, Miroslav ; Daňhel, Aleš
Silver solid amalgam represents suitable alternative electrode material to metallic mercury, Controlled electrodeposition of variable silver amalgam particles (AgAP) on the surface of pyrolitic graphite electrode from an electrolyte containing Agt It and Hg(II) ions is reported as a novel method suitable lot preparation of perspective supporting materials Scanning electron microscopy including energy-disperse X-ray spectrometer and image processing software were used for analysis of composition and morphology of AgAP on POE A model electrochemically reducible 4-niirophenol was used to test a potential applicability of AgAp-PGE in electroanalytical methods.
Analysis of Products of Nontemplate Enzymatic Synthesis of DNA Oligonucleotides using Voltammetric Methods
Hermanová, Monika ; Havranová-Vidláková, Pavlína ; Ondráčková, Anna ; Fojta, Miroslav
Nontemplate DNA synthesis is a feature specific for a special type of DNA polymerase, terminal deoxynucleotidyl transferase (TdT). This enzyme is able. to randomly add nucleotides to a sintde-stranded DNA primer, provided the 3'OH end of the primer is accessible, Here we show that voltammetric analysis based on hanging mercury drop electrode (EPODE) and pyrolytic graphite electrode (PGE) enables to study this nontemplate DNA synthesis.
Study of Synthetic Oligonacleotides Containing Guanine by Voltammetry on a Graphite Electrode
Hejduková, M. ; Špaček, Jan ; Fojta, Miroslav ; Havran, L. ; Renciuk, D.
Electrochemical oxidation of specifically designed DNA hexamers containing guanine has been studied in aqueous acetate buffet (pH 5) at a pyrolytic graphite electrode (PGE) by linear sweep voltammetry (LSV) Influence of the oligonucleotide composition and concentration was investigated It seems that short oligonucleotides containing guanine produce oxidation signals. which are sensitive to their structural properties Simple electrochemical techniques us may be useful tool for monitoring of structural changes of DNA.
Preparation and Characterization of Silver Amalgam Particles on Gold Electrode Surface
Havranová-Vidláková, Pavlína ; Šebest, Peter ; Ligmajer, Filip ; Fojta, Miroslav ; Daňhel, Aleš
This work is focused on the preparation of silver amalgam particles by its direct electrodeposition on gold surfaces using double pulse chronoamperometry from solution containing soluble Ag+ and Hg2+ ionts. During the electrodepositions of silver amalgam particles, different: i) parameters of chronoamperometry, ii) Ag/Hg ratio in solution and iii) gold electrodes were studied. All the prepared amalgam particles were characterized by scanning electron microscope with energy dispersive X-ray spectroscopy and electrochemical methods. Voltammetric application of the gold electrodes decorated by sliver amalgam particles was confirmed by analysis of model organic nitrocompound using cyclic voltammetry.
Electrochemical Study of Osmium Tetroxide Comptests Reactivity to DNA Bearing Butylacrylate
Havran, Luděk ; Havranová-Vidláková, Pavlína ; Špaček, Jan ; Vítová, Lada ; Hermanová, Monika ; Fojta, Miroslav
Coniplexes of osmium tetroside with nitrogen ligands (Os,L e.g.. with 2,2'-bipyridine (bpy) find application in redox labelling of DNA.. probing of DNA structure, and in studies of DNA interaction with other molecules Os,L preferentially react with pyrimidines in single strand DNA producing electroactive adducts Primary reaction site for Os,L is C=C double bond in pyrimidine nucleobases. In this contribution we introduce a new two-step technique of DNA modification with Os,bpy, consisting in enzymatic construdion or DNA beating butyl acrylate (BA) moieties attached to uracil or T-deaza adenine, followed by chemical modification of a reactive C=C double bond in BA residue.

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