National Repository of Grey Literature 34 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Electrochemical Analysis of Chemically Modified DNA at Gold Electrodes
Vidláková, Pavlína ; Havran, Luděk ; Fojta, Miroslav
DNA labeling is used to increase sensitivity of its electrochemical detection. Covalently bound markers based on a complex of osmium tetroxide with 22-bipyridine(Os,bipy) is one of those frequently applied. Os bipy reacts with pyrimidines (mainly thymines) in single stranded regions of DNA, therefore it represents a useful marker for the analysis of DNA structure or labeling of hybridization probes . Another possibility of DNA labeling is the incorporation of chemically modified dNTPs into DNA molecules with using primer extension. DNA labeling in connection with voltammetry at gold electrodes has application potential in development of sensors for studying of DNA structure and interaction.
Label-free Detection of Single Nucleotide Polymorphism Using Selective Incorporation of Biotin Anchor and Magnetoseperation on Streptavidin Magnetic Beads
Plucnara, Medard ; Havran, Luděk ; Ecsin, E. ; Erdem, A. ; Fojta, Miroslav
Novel approach of SNP detection in model synthetic oligonucleotides is described.This assay requires only intrinsic electrochemical properties of DNA and except of incorporation of biotin affinity tag, no any labeling or any other modification step is needed. Very good resolution for different variants of polymorphism as well as sufficiently low detection limits were achieved.In combination with using pencil graphited electrode this assay could be very simple and cheap tool for SNP typing.
New Ligands for Modification of DNA by Osmium Tetroxide Reagents
Havran, Luděk ; Zenka, Martin ; Fojta, Miroslav
Besides DNA intrinsic electroactivity, modification of DNA by redox active tags find wide use in electrochemical analysis of DNA interactions and damage. Application of these tags can improve specificity of the analysis. One from utilized labels in this field are complexes of osmium tetroxide with nitrogen ligands, which produce with DNA electroactive covalent adducts. These complexes preferentially react with thymine in single strand DNA. Type of used ligand influence electrochemical behavior forming adducts. In this contribution will be presented results which are acquired by testing of set a new ligands based of quinone and substituted 1, 10-phenanthroline.
Analysis of Denatured PCR Products Modified with 7-deazapurine Bases at Hanging Mercury Drop Electrode
Dudová, Zdenka ; Špaček, Jan ; Havran, Luděk ; Pivoňková, Hana ; Fojta, Miroslav
7-deazapunines are synthetic analogues of natural purine nucleobases which can pair with pyrimidines, retaining pairing complementarity of their parent purines. There is replaced N7 atom by CH group in 7-deazapurines so that DNA modified with them don't participate in Hoogsteen basepairing and don't form alternative structures. Here is a study of 7-deazapurines incorpotated into DNA measured at HMDE by CV and ACV. While 7-deazaadenine was reduced at the HMDE, giving rise to a similar irreversible cathodic peak as the natural adenine, 7-deazaguanine didn't yield any peak analogous to the peak G due to Guanine, in Agreement with a loss of corresponding redox in 7-deazaguanine.
Electrochemically Switchable DNA Tags
Vidláková, Pavlína ; Havran, Luděk ; Fojta, Miroslav
DNA labelling is used for the improvement of sensitivity and selectivity of its electrochemical detection. Attachment of a new electroactive group into DNA strand can give rise to a new electrochemical signal. For analysis of label DNA is often advantageous to use redox tags giving reversible redox signal because of the possibility of performing several repeated measurements with one sample. Some redox tags give reversible redox signal directly in their introduced forms. Reduction/oxidation of other redox tags is irreversible but reduction/oxidation of these groups can give rise to new groups that yield reversible electrochemistry.
Novel Reactive Groups for Modification DNA by Oxoosmium Complexes
Havran, Luděk ; Vidláková, Pavlína ; Špaček, Jan ; Hermanová, Monika ; Fojta, Miroslav
DNA is naturally electroactive moleclue producing several intrinsie voltammetric signals. Some of them found appliction in electrochemical analysis of DNA interactions and damage. In particular types of applictaions is a suitable use DNA labelling by redox active tags to increase selectivity and sensitivity of analysis.One type of long-term used tags are complexes of osmium tetroxide with nittrogen ligunds (Os,L). These complexes preferentially react with pyrimidines in single stand DNA producing electractive adducts. primary reaction site for Os,L is C-C double bond in pyrimidine nucleobases. In this contribution will be presented results acquired with DNA containing chemically modified nuclebase.
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.
Voltammetric Analysis of Anthraquinone-labeled Nucleotide Triphosphates and Oligonucleotides at Gold Electrodes
Vidláková, Pavlína ; Balintová, Jana ; Havran, Luděk ; Hocek, Michal ; Fojta, Miroslav
DNA labelling is used for increase of sensitivity of electrochemical detection. When the DNA or oligonucleotides (ONs) are chemically modified, their electrochemical responses can be changed depending on electrochemical activity of the introduced moiety. One option of DNA labeling is incorporation of chemically modified nucleotides using corresponding deoxynucleotide triphosphates (dNTPs) into DNA molecules with using primer extension (PEX). In our study we used anthraquinone labeled dNTPs and ONs with enzymatically incorporated anthraquinone labeled nucleotides. Thus synthesized ON stretch bearing the anthraquinone tags was electrochemically analyzed using voltammetry at gold electrodes.
Redox DNA Labeling - from Simple DNA Detection by Osmium Tetroxide Complexes Modification to Ratiometric Sequence Analysis
Havran, Luděk ; Balintová, Jana ; Vidláková, Pavlína ; Macíčková-Cahová, Hana ; Pivoňková, Hana ; Hocek, Michal ; Fojta, Miroslav
DNA is electroactive molecule producing analytically useful intrinsic voltammetric signals. For some applications is a useful use redox active tag to improve specificity of the analysis. One from approaches how to prepare DNA bearing redox label is its modification by complexes of osmium tetroxide with nitrogen ligands. This method find wide used in highly sensitive DNA detection and in development of electrochemical DNA hybridization sensors. Another possibility for preparation of redox labeled DNA is incorporation of redox tags modified deoxynucleotide triphosphates by DNA polymerases. In this contribution will be demonstrated application of various redox labels in electrochemical analysis of DNA.
Magnetic Beads-Based Electrochemical Techniques for DNA-Protein Interaction Monitoring
Fojta, Miroslav ; Pivoňková, Hana ; Němcová, Kateřina ; Horáková Brázdilová, Petra ; Havran, Luděk ; Orság, Petr ; Vidláková, Pavlína ; Macíčková-Cahová, Hana ; Balintová, Jana ; Hocek, Michal
Electrochemical techniques, in connection with separation of nucleoprotein complexes at magnetic beads, are suitable for the monitoring of DNA-protein interactions. For the detection of complexes captured at the beads it is possible to utilize intrinsic electrochemical activity of the protein, intrinsic structure-selective signals of the DNA, or indicator DNA substrates tail-labeled with electroactive moieties.

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