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Survey of kinetics of spontaneous ozone decay in water
Fendrych, Adam ; Mergl, Václav (referee) ; Mega, Jaroslav (advisor)
In the general part of this diploma thesis are presented technical information collected on the issue of spontaneous decay of ozone in water solution and problems with analytical monitoring of these processes. Particular attention is paid to influence of pH value, bicarbonate and peroxide concentration on ozone decay kinetics. Experimental part is focused on the use of spectrophotometry in the study of chemical reactions associated with the spontaneous decay of ozone in distilled and tap water depending on pH and temperature after saturating of water by ozone prepared from air and pure oxygen. Direct photometry in UV range of spectrum (at 260 nm) was used to monitoring of ozone decomposition kinetics.
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Improved determination of DNA duplex stability by using UV spectroscopy
Víšová, Ivana ; Štěpánek, Josef (advisor) ; Kočišová, Eva (referee)
This work deals with determination of thermodynamic parameters concerning the temperature induced decomposition of DNA duplexes. Precise temperature dependences of solution UV absorption spectra have been measured for several concentrations. Proposals and tests of various data analysis procedures, with aim to find out optimal way how to determine the thermodynamic potentials changes, represent the core of the work. It has been demonstrated that the combination of a factor analysis and a fit of thermodynamic equations to temperature dependences of obtained coefficient values, enables these parameters to be obtained from a measurement performed for only one concentration and with better precision than by using the so far recommended method based on a melting temperature determination for several concentrations.
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Thermodynamics of complex formation by miRNA
Vacková, Anežka ; Štěpánek, Josef (advisor) ; Mojzeš, Peter (referee)
The bachelor thesis concerns microRNA (miRNA), short RNA molecules that mediate post-transcriptional regulation of gene expression by binding to a target mRNA. They usually form extended duplexes consisted of short tracks of Watson-Crick basepairs separated by internal loops, mismatched pairs, or bulges. The thesis represents a study of the effect of structural anomalies, the internal loop and the bulge, on the structural stability miRNA Let7 complex with its target LCS1 sequence at mRNA lin-41 from Caenorhabditis Elegans. The task was solved by recording temperature dependent UV absorption spectra of solutions containing mixtures of the mentioned above RNA sequences and their mutated analogs, analysis of the spectral changes by using a singular decomposition method followed by fitting to a thermodynamic model. The determined thermodynamic characteristics of the complexes and spectral changes caused by a temperature increase or the complex dissociation are the outcome of the work.
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miRNA complexes with the target RNA sequence
Homolka, Radim ; Štěpánek, Josef (advisor) ; Římal, Václav (referee)
miRNAs are short non-coding RNA molecules which play role in post-transcriptional regulation of gene expression. Thus, miRNAs are related to a variety of physiological processes and diseases, e.g. some tumours or viral infections. In this diploma thesis we studied temperature-induced dissociation of complexes that simulated pairing of miRNA with target mRNA. For these purposes we used UV absorption spectroscopy and Raman spectroscopy. Measured spectra were then treated by means of a factor analysis. The aim of the thesis was to determine thermodynamic parameters of the complexes dissociation and to clarify how inner loops and bulges affect the stability of oligonucleotide duplexes. Also, we have tested the suitability of the used approach for study of oligonucleotide complexes. We have shown that factor analysis of temperature dependent UV absorption spectra is a proper base to determine thermodynamic parameters of the duplex dissociation. Raman spectra were affected by large errors, nevertheless they enabled to observe some structural changes related to the transition. It has been shown that the bulge loop present in the studied complex reduces both its flexibility and the energetic preference of its formation.
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Spectroscopic Study of miRNA Structure and Interactions
Homolka, Radim ; Štěpánek, Josef (advisor) ; Maloň, Petr (referee)
MiRNA are short RNA molecules that mediate post-transcriptional regulation of gene expression by binding to a target mRNA. In this thesis, some structural properties and thermodynamic parameters (melting temperature, enthalpy ∆H and entropy ∆S changes connected with the transition between particular conformations) of oligonucleotides simulating complex of miRNA and mRNA, were characterized by using spectroscopic methods and a gel electrophoresis. Temperature dependences of UV and Raman spectra were measured, the results treated by means of a factor analysis, and the abovementioned thermodynamic parameters determined by a fit to a feasible model. The outputs have demonstrated the capability of the used methods to determine thermodynamic and structural properties of non-canonical RNA complexes. Powered by TCPDF (www.tcpdf.org)
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Improved determination of DNA duplex stability by using UV spectroscopy
Víšová, Ivana ; Štěpánek, Josef (advisor) ; Kočišová, Eva (referee)
This work deals with determination of thermodynamic parameters concerning the temperature induced decomposition of DNA duplexes. Precise temperature dependences of solution UV absorption spectra have been measured for several concentrations. Proposals and tests of various data analysis procedures, with aim to find out optimal way how to determine the thermodynamic potentials changes, represent the core of the work. It has been demonstrated that the combination of a factor analysis and a fit of thermodynamic equations to temperature dependences of obtained coefficient values, enables these parameters to be obtained from a measurement performed for only one concentration and with better precision than by using the so far recommended method based on a melting temperature determination for several concentrations.
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Survey of kinetics of spontaneous ozone decay in water
Fendrych, Adam ; Mergl, Václav (referee) ; Mega, Jaroslav (advisor)
In the general part of this diploma thesis are presented technical information collected on the issue of spontaneous decay of ozone in water solution and problems with analytical monitoring of these processes. Particular attention is paid to influence of pH value, bicarbonate and peroxide concentration on ozone decay kinetics. Experimental part is focused on the use of spectrophotometry in the study of chemical reactions associated with the spontaneous decay of ozone in distilled and tap water depending on pH and temperature after saturating of water by ozone prepared from air and pure oxygen. Direct photometry in UV range of spectrum (at 260 nm) was used to monitoring of ozone decomposition kinetics.
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