National Repository of Grey Literature 67 records found  beginprevious38 - 47nextend  jump to record: Search took 0.01 seconds. 
Electrochemical Investigation of Different Boron Cluster Compounds in Water-based Electrolytes
Fojt, Lukáš ; Vespalec, Radim ; Fojta, Miroslav ; Grüner, Bohumír
Boron cluster compounds (BCC) belongs to one or the proud sing compounds which ace used for medical treatment Their use for biochemical purposes is connected with use of water-based environments. Up to now, the BCC were predominantly characterized in non-aqueous milieus Therefore, we decided to undertake electrochemical research of BCC in water-based electrolytes. We have investigated several boron clusters with structures containing different number of vertexes (from 3 to 18), The structures were modified by endo- and exo- skeletal substituents. All used BCC were electrochemically active in broad potential region. which implies their possible use as biomarkers with tunable electrochemical response.
Searching for Electrochemical Reduction Mechanism of Azidophenyl DNA Labels
Daňhel, Aleš ; Trošanová, Zuzana ; Balintová, Jana ; Hocek, Michal ; Fojta, Miroslav
This contribution brings new information to sporadic scientific results concerned to electrochemical reduction of aromatic azides. Selected compounds used as perspective DNA labels or their structural constituents such as, 4-azidophenyltrifluoroboronic acid, 4-azidophenyl modified deoxycytidine and next probable analogous compounds and/or products of their reduction, were voltammetrically studied and compared to each other in order to reveal a mechanism of their electrochemical reduction at mercury electrodes in aqueous media. Preliminary results obtained by cyclic voltammetry at mercury and carbon based electrodes and by mass spectrometry of the products isolated from batch electrolysis on mercury pool by preparative chromatography are discussed.
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.
Voltammetric Behavior of 4-Aminophthalimide Label using Hanging Mercury Drop Electrode
Ferenčíková, Z. ; Daňhel, Aleš ; Riedl, Jan ; Hocek, Michal ; Fojta, Miroslav
4-aminophthalimide (API), covalently attached to nucleotide (dCTP or dATP) has recently beendesigned as a fluorescent label for the detection of DNA-protein interaction. However API is electrochemically reducible and therefore it is possible to use alternatively the API-modified nuclotides as DNA redox labels. The electrochemical behavior of labeled nucleotides and labeled DNA was studied using cyclic voltammetry and transfer stripping cyclic voltammetry at hanging mercury drop electrode. Observed CVs showed irreversible reduction signals of 4-aminophthalimide label without production of consequently oxidizable/reducible species.
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.
Using Anthraquinone Labeled Nucleotide Triphosphates for Electrochemical Analysis of DNA
Vidláková, Pavlína ; Balintová, Jana ; Horáková Brázdilová, Petra ; Havran, Luděk ; Orság, Petr ; Fojta, Miroslav ; Hocek, Michal
Base-modified anthraquinone-nucleotide triphosphates were used for DNA labeling. Anthraquinone modified nucleotides were incorporated into DNA by primer extension with KOD polymerase. In cyclic and square wave voltammetry at HMDE or PGE antraquinone gave a well developed characteristic signal suitable for differentiation of the labeled DNA from unlabeled one.
Utilisation of enzymatic labelling with 4-aminophtalimide and 4-hydroxybenzylideneimidazolinone fluorescent derivates for monitoring of DNA-protein interaction
Orság, Petr ; Pivoňková, Hana ; Riedl, Jan ; Hocek, Michal ; Fojta, Miroslav
The 5’-substituted deoxycytosine triphosphates with conjugated solvatochromic derivates of 4-aminophtalimide (API) and derivates of the green fluorescent protein, 4-hydroxybenzylideneimidazolinone (HBI) were synthetized and successfully tested for enzymatic incorporation using primer extension assay. Site specifically labelled oligonucleotide probes were prepared and tested for interaction with p53 and SSB proteins, displaying distinct DNA-binding properties. The incorporation of multiple fluorescent labels did not interfere with natural protein binding and protein interaction leaded in both cases the to the gradual ratiometric increase of the fluorescence intensity moreover accompanied with the changes of the fluorescence emission spectra profile. Neither effect was observed after incubation with BSA, non-DNA binding protein, confirming the specificity of the interaction. Modified nucleoside triphosphates with conjugated fluorescence labels derivates of API and HBI can be used as substrates for preparation of the specific oligonucleotide labelled probes and provide the novel tool for studying and monitoring the DNA-protein interaction.
Electrochemical analysis of DNA using switchable redox moieties
Fojta, Miroslav ; Daňhel, Aleš ; Horáková Brázdilová, Petra ; Plucnara, Medard ; Pivoňková, Hana ; Havran, Luděk ; Vidláková, Pavlína ; Raindlová, Veronika ; Balintová, Jana ; Macíčková-Cahová, Hana ; Hocek, Michal
Labelling of DNA with electrochemically active moieties proved to be a convenient way to the development of electrochemical techniques for the sequence-specific DNA sensing. Through combinations of various labels differing in redox potentials, independent redox coding of different DNA sequences or individual nucleobases can be attained. Applications possibilities of electrochemistry in analysis of modified DNAs are further extended by facile monitoring of chemical conversion of reactive groups on DNA during post-labelling with ultimate redox labels. In addition, controlled in situ electrochemical conversions of specific intrinsic and extrinsic DNA components can be utilized to switch their electrochemical signals and improve signal resolution.
New oxidative labels for electrochemical detection of DNA
Simonova, Anna ; Havran, Luděk ; Fojta, Miroslav ; Hocek, Michal
New dCTP and dATP derivatives bearing oxidizable labels have been synthesized and incorporated to DNA for studying their electrochemical properties in different sequences of DNA.

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