Biofyzikální ústav

Biofyzikální ústav Nalezeno 298 záznamů.  předchozí11 - 20dalšíkonec  přejít na záznam: Hledání trvalo 0.01 vteřin. 
P36 VOLTAMETRIC DETECTION OF DNA DELETION ON PENCIL ELECTRODE
Haroniková, Lucia ; Špaček, Jan ; Fojta, Miroslav
In this work, we present a new qualitative approach of detection of PCR products using electrochemistry on pencil electrodes. PCR products with an incorporated biotin-labeled dNTP (dCTP in this study) are detected via conjugated streptavidinealkaline phospatase. 1-Naphthyl phosphate (1-NP), which is dephosphorylated by alkaline phosphatase to release 1-naphthol, was used as a substrate in electrochemical detection of the PCR product. Voltammetric measurement on disposable pencil electrode is a very cheap and easy to use method. The system was optimized for plasmid DNA PCR product with potential to detect human genome DNA products and possible application in gene deletion monitoring.
ANALYSIS OF SEQUENCE SPECIFIC INTERACTIONS BETWEEN DNA AND P53 FAMILY PROTEINS BY ELISA, SLOT-BLOT AND EMSA
Adámik, Matěj ; Holanová, L. ; Navrátilová, Lucie ; Nygrinova, J. ; Pokorova, J. ; Petr, Marek ; Tichý, Vlastimil ; Brázdová, Marie
DNA-protein interactions of core domains of p53, p63 and p73, members of tumor suppressor p53 family, were investigated by multiple methods with regard to verifying the sequence specificity with which short target oligonucleotides/long DNA fragments can be recognized. The sequence specificity of core domains and wtp53 full protein binding to specific sequence in both types of DNA substrates was confirmed in solution, on surface and in gels by ELISA, slot-blot and EMSA.
TAIL-LABELED OLIGONUCLEOTIDE PROBES FOR A DUAL ELECTROCHEMICAL MAGNETIC IMMUNOPRECIPITATION ASSAY OF DNA-PROTEIN BINDING
Hermanová, Monika ; Špaček, Jan ; Orság, Petr ; Fojta, Miroslav
A novel assay for detection of DNA-protein binding has been developed. Oligonucleotides bearing or lacking specific binding site of the p53 protein were tail-labeled by two different modified deoxynucleotide triphosphates using terminal deoxynucleotidyl transferase. Electrochemical detection enabled to discriminate between sequence-specific and non-specific p53-DNA binding in a competition assay.
Study on the Electrophoretic Behaviour of Short Oligodeoxyribonucleotides in Fused Silica Capillaries. A Preliminary Communication
Vítová, Lada ; Fojta, Miroslav ; Vespalec, Radim
Effects of background electrolyte pH, composition and concentration on the electrophoretic transport of short oligodeoxyribonucleotides (ODNs) in fused silica capillaries have been investigated in the presented study. Mobilities and separation efficiencies of ODNs peaks varied with all three background electrolyte characteristics. Just changes in the background electrolyte characteristics and acid-base properties of ODNs are not sufficient for a systematic explanation of the observed variations. Despite the indicated complexity of ODNs electrophoretic behaviour, we show that very high separation efficiencies of ODNs peaks can be achieved in background electrolytes of physiological pH.
Primer Extension Reaction at the Gold Electrode Surface
Vidláková, Pavlína ; Havran, Luděk ; Fojta, Miroslav
One option of covalent DNA labeling is incorporation of chemically modified nucleotides using corresponding deoxynucleotide triphosphates into DNA molecules using polymerase-catalyzed primer extension. Primer extension is usually performed in solution and then the product is analyzed, often after a suitable separation. In our study we tested the possibility to prepare oligonucleotides with enzymatically incorporated anthraquinone labeled nucleotides using primer extension on templates immobilize at a gold electrode surface.
Possibility of Using Purine Oxidation Signals for DNA Sequence Analysis
Špaček, Jan ; Cahová, Kateřina ; Havran, Luděk ; Fojta, Miroslav
Signals provided by electrochemical oxidation of single stranding DNA on the surface of pyrolytic graphite electrode, which correspond to the oxidation of adenine and guanine (A and G) are known for over forty years. The mechanism of oxidation of free A and G as well as nucleoside mono-, and triphosphates of these bases is know but the mechanism of oxidation of purines in the DNA still remains unexplained. Ratiometry of A and G signals could be a new tool for DNA sequence analysis, if signals of A and G oxidation obtained from single-stranded DNA adsorbed at the electrode surface are proportional to the number of oxidized As and Gs in studied samples. Our preliminary results suggest that there is a correlation, yet we encountered problems, which yet has to be addressed and explained before this method could be applied for DNA analysis.
Examples of Using of Electrochemical Detection at Pencil Graphite Electrode with Enzymatic Labeling for Analysis of Nucleotide Sequence
Plucnara, Medard ; Haroniková, Lucia ; Špaček, Jan ; Havran, Luděk ; Horáková, Petra ; Pivoňková, Hana ; Ecsin, E. ; Erdem, A. ; Fojta, Miroslav
Many examples of utilization of enzymatic labeling for DNA sequence analysis has been described in literature so far. Some of them involve hybridization with complementary biotinylated probe, while others use incorporation of biotinylated nucleotides into DNA strand by DNA polymerases. Common approach is then binding of streptavidine-enzyme conjugates to biotin tags and incubation with substrate, which is converted to detectable product. Here, two recent applications using this principle are described for the detection of PCR amplicons and for SNP typing. Both techniques are combined with detection at pencil graphite electrodes.
Studies of Protein-DNA Interactions using Immunoprecipitation with DNA Probes Labelled with Electroactive Groups
Hermanová, Monika ; Špaček, Jan ; Pivoňková, Hana ; Fojta, Miroslav
Different electrochemically active species were tested for labelling of DNA probes and detection of DNA-protein binding. As the DNA probes, oligonucleotides bearing or lacking specific binding site of the p53 protein were chosen. They were tail-labelled either via chemical modification of single-stranded (ss) oligo(dT) DNA tails with an oxoosmium complex, or via enzymatic synthesis of the ss tail by terminal deoxynucleotidyl transferase and deoxynucleoside triphosphates modified with electrochemically reducible moieties. Electrochemical detection enabled to discriminate between sequence-specific and non-specific p53-DNA binding.
Natural and Synthetic Components of Nucleic Acids as Reactive Sites for DNA Modification by Osmium Tetroxide Complexes
Havran, Luděk ; Špaček, Jan ; Rozkosna, Jana ; Fojta, Miroslav
Natural DNA electroactivity find wide use in electrochemical analysis of its interactions and damage. For some applications is useful applied redox active tag to improve specificity of the analysis. One from utilized labels in this field are complexes of osmium tetroxide with nitrogen ligands (Os, L), which produce with DNA electroactive covalent adducts. Prime reaction site for Os, L is C=C double bond in pyrimidine nucleobases. If is 2,2'-bipyridine used as ligand, reaction is specific for single strand DNA. In this contribution will be presented results of electrochemical analysis of Os, bipy adducts with different ODN containing chemically modified purine bases.
Electrochemical Reduction and Oxidation of Nucleic Acids Bases and their Analogues: a Brief Overview
Fojta, Miroslav ; Špaček, Jan ; Dudová, Zdenka ; Pivoňková, Hana ; Daňhel, Aleš ; Fojt, Lukáš ; Havran, Luděk
Nucleic acids are known as electroactive biomacromolecules containing electrochemically reducible or oxidizable constituents. Nucleobases cytosine, 5-methylcytosine, adenine and guanine can be reduced in aqueous media on mercury or silver amalgam electrodes. Oxidation of all natural nucleic acids bases (in addition to the above mentioned ones, also uracil and thymine) was demonstrated using various types of carbon electrodes. Some of synthetic nucleobases or nucleotide analogues (e g., 7-deazapurines, cytidine analogues used as epigenetic modulators, etc.) exhibit specific electrochemical properties that differ from those of the parent bases and can be utilized to determine the given substance in the presence of natural nucleic acids or their components.

Biofyzikální ústav : Nalezeno 298 záznamů.   předchozí11 - 20dalšíkonec  přejít na záznam:
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