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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.
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Voltammetric Techniques for Analysis in a Single Drop of a Solution
Gajdar, J. ; Goněc, T. ; Jampílek, J. ; Brázdová, Marie ; Bábková, Zuzana ; Fojta, Miroslav ; Barek, J. ; Fischer, J.
This contribution describes miniaturization of voltammetric methods and some of the main problems caused by reducing the sample volume to 20 mu L. This study was carried out in dimethyl sulfoxide solutions and buffered aqueous solutions with 10% DMSO at a glassy carbon electrode. A novel antibiotic agent, 1-hydroxy-N-(4-nitrophenyl) naphthalene-2-carboxamide, was used as a model substance. This analyte was determined by cathodic and anodic voltammetry. Elimination of the negative influence of dissolved oxygen was performed in various manners. Two most effective methods were square wave voltammetry that can be used in the presence of dissolved oxygen and removal of oxygen in a microcell with nitrogen atmosphere inside.
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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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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.
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Study of 2-Nitrofluorene Interaction with DNA at a Glassy Carbon Electrode
Skalová, Štěpánka ; Stávková, K. ; Vyskočil, V. ; Barek, J.
2-Nitrofluorene (2-NF) is a nitrated polycyclic aromatic hydrocarbon (NPAH) which occurs as the environmental pollutant. It is a potential carcinogen and mutagen. Interaction of deoxyribonucleic acid (DNA) with 2-NF was monitored using an electrochemical DNA biosensor prepared from a glassy carbon electrode (GCE) and low-molecular-weight DNA by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and square-wave voltammetry (SWV).\nThere were no damaging interactions observed between DNA and 2-NF using EIS. However, CV shows intercalation of this substance into the DNA structure to form the complex 2-NF–DNA. Intercalation was also observed by SWV, confirming intercalation to reduce the number of electroactive sites and thus reducing the peak heights of adenosine and guanosine.
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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.
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Voltametrická analýza nukleosidtrifosfátů a oligonukleotidů značených antrochinonem na zlatých elektrodách
Vidláková, Pavlína ; Balintová, Jana ; Havran, Luděk ; Hocek, Michal ; Fojta, Miroslav
Elektrochemická aktivita nukleových kyselin byla objevena v 50. letech 20. století a od té doby je používána ke studiu struktury a interakcí přirozených i modifikovaných molekul nukleových kyselin i syntetických oligonukleotidů. Přestože je přirozená DNA sama o sobě elektrochemicky aktivní a je možné ji studovat na různých typech elektrod, je pro řadu analytických aplikací praktické použít DNA značenou elektroaktivními molekulami (například komplexy přechodných kovů, amino- nebo nitroskupinami, antrachinonem apod.). Tyto látky podléhají redoxním reakcím a dávají takto modifikované DNA nové elektrochemické vlastnosti, které je možné využít pro studium struktury a interakcí nukleových kyselin a v oblasti DNA diagnostiky.
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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.
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