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Analysis and characterization of liposomes using capillary electrophoresis
Orgoníková, Andrea ; Křížek, Tomáš (advisor) ; Coufal, Pavel (referee)
4 Abstract This diploma thesis deals with the analysis of three different types of liposomes using capillary electrophoresis with UV-VIS and laser induced fluorescence detection and the use of liposomes as a pseudostationary phase for analyte separations by liposome electrokinetic chromatography method. In experiments with DSPC-DSPG-PEG2000-DMPE liposomes encapsulating 5-fluoruracil, the peak of liposomes with encapsulated 5-fluoruracil and the peak of free 5-fluoruracil were successfully identified in the electropherograms. Both peaks showed the same absorption spectrum in the UV region, thus confirming their identity. It was proved that capillary electrophoresis with UV-VIS detection is useful for the separation and detection of free and encapsulated drug, which is necessary to determine the efficiency of encapsulation. By monitoring the change of effective analyte mobility after the addition of liposomes to the background electrolyte the applicability of the investigated liposomes in liposome electrokinetic chromatography was evaluated. A change in mobility was observed for negatively charged 5-fluoruracil and positively charged tryptamine and p-toluidine. The absolute value of the effective mobility of negatively charged 5-fluoruracil decreased by 18.2 % due to interactions with liposomes and effective...
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Electrophoretic determination of oxidized and reduced form of glutathion in plant material
Durychová, Eva ; Křížek, Tomáš (advisor) ; Kubíčková, Anna (referee)
This work is based on a previously published method for the determination of twenty proteinogenic amino acids by capillary electrophoresis with contactless conductivity detection and deals with possibility of its use for the determination of oxidized (GSSG) and reduced (GSH) forms of glutathione with amino acids. The theoretical part firstly deals with brief introduction of the properties and importance of glutathione and its protection against autooxidation, especially by alkylation with N-ethylmaleimide (NEM), which binds to GSH to form its alkylated form (GSH-NEM). Then, a brief summary of the available methods for determination of glutathione is given, with a focus on the already developed capillary zone electrophoresis methods. Finally, it briefly presents the electrophoretic method for the determination of twenty proteinogenic amino acids on which this work is based. In the experimental part, the integration of the determination of both forms of glutathione into the method for the determination of proteinogenic amino acids is presented. First, a simplified, less time consuming method was tested in shorter 50.0 cm capillary without hydroxyethylcellulose, where both forms of glutathione were separated at baseline within 10 minutes. Relative standard deviations of peak areas (GSH 2.1%; GSSG...
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Use of fluorescence methods for the study of protein interactions
Johaníková, Klára ; Bezděková,, Jaroslava (referee) ; Pavelicová, Kristýna (advisor)
The diploma thesis "Use of fluorescence methods for the study of protein interactions" is focused on the use of fluorescence methods for the study of protein interactions using electromigration methods and Förster resonance energy transfer (FRET). The aim of this work was to create a bioconjugate of metallothionein (MT) protein with quantum dots (QDs) and commercial dyes. FRET was subsequently studied between these conjugates. QDs were synthesized under UV light and conjugation with MT was performed via a carbodiimide zerolengthcrooss-linker (EDC / sulfo-NHS), which serves to activate carboxyl groups and allows bioconjugation of the ligand by covalent bonding. Due to the high proportion of cysteines in MT, this protein has a very high affinity for metals. It is also involved in scavenging free radicals and there are studies that show that MT is overexpressed in cancer cells. Attention was also paid to the study of MT dimerization, which leads to an understanding of oxidative dimerization of MT and thus can contribute to understanding the formation of free radicals in the body and to deepen the knowledge about neurodegenerative disorders such as Parkinson's or Alzheimer's disease or amyotrophic lateral sclerosis. The formation of the MT dimer was confirmed by energy transfer between the donor (QDs) and the acceptor (commercial dye-cyanine) through the physical phenomenon of FRET and MALDI-TOF-MS.
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Application of Capillary Electrophoresis in Forensic Molecular Genetic Investigation
Grafnetterová, Anna ; Doubková, Klára (advisor) ; Coufalová, Pavla (referee)
5 Abstract The capillary electrophoresis (CE) is an analytical method based on the principle of the traditional plate electrophoresis. Modern ways of fluorescence marking and the detection result in the higher reliability of analyses as well as in more precise results. The utilization of this method is wide within a lot of science fields. In special cases this method can even replace methods used so far, i.e. HPLC. The CE is mainly used in the forensic investigation in particular for person identification based on the DNA analysis of the even minimal sample amount. The STR analysis is an example of such examination. It uses short tandem repeats with high variability within the population. Commercial companies e.g. Promega Corporation, Applied Biosystems etc., develop corresponding instrumentation, software and kits which are important for receiving correct data. As a final result it is obtained DNA profile evaluated by comparison of samples from the "crime scene" with the reference samples. Besides the using in the human domain the DNA profiles are often used in the veterinary practice, in animal (cats, dogs, horses, cattle etc.) raising or breeding, for improving the particular characteristics. Key words: capillary electrophoresis fluorescent labeling STR STR analysis DNA profil
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Separation and determination of possible products of enzymatic cleavage of 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside using capillary electrophoresis
Velvarská, Romana ; Křížek, Tomáš (advisor) ; Kalíková, Květa (referee)
This work deals with the development and optimization of conditions of a method that can be used to compare the activity of the enzyme β-N-acetylhexosaminidase in hydrolysis of a natural substrate and a chromogenic substrate, which is often used in the study of enzyme kinetics. As a substrate, 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside was selected for cleavage. This oligosaccharide contains bond, which the enzyme cleaves in the natural substrate, and the bond that occurs in the chromogenic substrate. To determine the products arising from enzymatic hydrolysis of 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside, capillary zone electrophoresis was used. First, it was necessary to find the optimal composition of the electrolyte, its pH and concentration. The optimal background electrolyte was a solution of sodium tetraborate at a concentration of 25 mmol/l and a pH of 10.25. Subsequently, repeatability, calibration curves and linearity, limit of detection and limit of quantification were investigated. Repeatability of migration times ranged up to 0.6%, the repeatability of peak areas between 2.5 and 6.3%. Limits of detection were ranging from 0.005 to 0.120 mmol/l. Finally, the optimized method was successfully used to monitor the actual enzyme cleavage.
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Comparison of gel and capillary electrophoresis of proteins
Krbec, Michal ; Franěk, Tomáš (advisor) ; Kotaška, Karel (referee)
Electrophoresis of serum proteins is one of the methods used in laboratory diagnosis of pathological conditions, but also for research purposes. This is a one-step method, which involves isolation of individual proteins from a mixture (mostly blood proteins) in the electric field in the presence of a suitable buffer and a suitable carrier based on their different mobility, dependent on their surface charge and molecular weight. Originally the carrieer used to be a paper, later cellulose acetate membrane and now it is almost exclusively agarose (purified agar with low endoosmosis) or polyacrylamide (PAA). My task in this work was to analyze a serie of samples by gel electrophoresis and subsequently analyze the same serie by capillary electrophoresis. Results obtained by both methods I worked numerically, compared with each other and statistically evaluated. The output of my work is a comparison of gel and capillary electrophoresis, evaluation of the advantages, disadvantages and especially the differences between these two methods.
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Use of capillary electrophoresis with UV photometric and electrospray ionization mass spectrometric detection for the study of interaction of compounds
Konášová, Renáta ; Jaklová Dytrtová, Jana (advisor) ; Mikšík, Ivan (referee) ; Tůma, Petr (referee)
Capillary electrophoresis (CE) is highly efficient separation method based on the different migration velocity of ions in liquid media in electric field. It is commonly used in analytical laboratories and due to the different separation principle it is applied as a complementary method to the chromatographic methods (HPLC and UHPLC). Beside the applicability of CE for quantitative/qualitative analysis, the method can be used also for physico-chemical characterization of compounds (e.g. determination of acid dissociation constants of weak electrolytes or stability constants of complexes). This work is focused on the applicability of CE methods for determination of physico- chemical characteristic of compounds (acid dissociation constants of triazole fungicides and stability constants of dibenzo-18-crown-6, benzo-18-crown-6 and 18-crown-6 ether complexes with metal ions in hydro-organic solvent mixtures) and on the possibility to use affinity CE (ACE) with electrospray ionization-mass spectrometric detection (ACE- ESI/MS) for the study of non-covalent interactions of compounds. For the online hyphenation of CE and ESI/MS, two highly sensitive CE-ESI/MS interfaces were tested: i) porous tip and ii) nano-sheath liquid flow. The ability of the CE-ESI/MS interfaces to effectively decouple spray and...
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Determination of proteinogenic amino acids by high-performance separation techniques
Hodek, Ondřej ; Křížek, Tomáš (advisor) ; Pacáková, Věra (referee) ; Tůma, Petr (referee)
(EN) Proteinogenic amino acids are key components of living organisms. Thus, the latest metabolomics research has focused on developing fast and sensitive methods for the determination of amino acids. In this context, this thesis contains two studies describing development of high-performance separation techniques for the quantification of amino acids. In the first study, a capillary electrophoresis method was developed for the determination of free amino acids in tobacco plants, particularly focusing on optimizing the extraction of amino acids from solid plant materials. The extraction procedure was optimized using design of experiments (DoE) to obtain the highest possible extraction yield of amino acids. Factors such as volume and concentration of the extraction solvent (hydrochloric acid) were assessed as the most significant. Subsequently, the optimal values of these factors were determined using response surface methodology (RSM). Lastly, proteinogenic amino acids were quantified using capillary electrophoresis with contactless conductivity detection and calibration with internal standard, which improved the precision of the method. The second study aimed at developing a supercritical fluid chromatography method for the determination of free proteinogenic amino acids in human plasma. The most...
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Selectively substituted cyclodextrins for analytical and pharmaceutical applications
Benkovics, Gábor ; Jindřich, Jindřich (advisor) ; Lhoták, Pavel (referee) ; Šindelář, Vladimír (referee)
3 Selectively substituted cyclodextrins for analytical and pharmaceutical applications Abstract This thesis is focused on the selective modification of cyclodextrins, and its primary aim is the preparation and characterization of mono- and persubstituted derivatives of cyclodextrins in a regioselective and straightforward manner. The work is divided into two main parts describing synthetic strategies and applications of modified cyclodextrins with one or several substituents, respectively. The first section deals with the introduction of a single chromophoric moiety on the cyclodextrin scaffold such as cinnamyl, rhodaminyl, fluoresceinyl and eosinyl groups. The complete set of monocinnamyl-α-cyclodextrin regioisomers has been prepared by direct alkylation, and the self-assembling properties of the corresponding regioisomers were thoroughly investigated by dynamic light scattering and NMR experiments. These investigations revealed that the different isomers (mono-6-O-, mono-2-O- and mono-3-O- cinnamyl-α-cyclodextrin) form distinct supramolecular species through intermolecular association. A fast method for the unambiguous identification of the pure regioisomers has also been developed based on a series of 2D NMR measurements. Xanthene-modified β-cyclodextrins, other representatives of monosubstituted...
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