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Preparation and testing of polyclonal antibodies against Cbf11 and Cbf12, the fission yeast CSL transcription factors
Tvarůžková, Jarmila ; Půta, František (advisor) ; Moserová, Michaela (referee)
CSL (CBF1/RBP-Jκ, Suppressor of Hairless, Lag-1) protein family members are transcription factors critical for metazoan development as the effectors of Notch signaling pathway as well as in a Notch-independent manner. CSL homologues have been identified in fungal organisms lacking the Notch signaling pathway. Cbf11 and Cbf12 are antagonistic paralogous proteins that are important for proper coordination of cell and nuclear division, regulation of cell adhesion and chromosome integrity in the fission yeast Schizosaccharomyces pombe. The activities of Cbf11 and Cbf12 proteins need to be finely balanced for their proper biological function, however, chromosomally tagged alleles of these proteins exhibit properties different from wild type. Therefore, the availability of specific antibodies would greatly enhance the study of CSL proteins in the fission yeast. In this bachelor's thesis, design and preparation of imunogen for commercial antibody production followed by antibody testing is presented. Using bioinformatics, suitable immunogenic Cbf11 and Cbf12 protein fragments were selected and the corresponding DNA sequences were cloned into an expression vector. His-tagged expression was optimized in a bacterial expression system and the native protein was purified using immobilized metal affinity...
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Metabolism carcinogens and drugs by the system of monooxygenases
Moserová, Michaela ; Stiborová, Marie (advisor) ; Entlicher, Gustav (referee) ; Čeřovská, Noemi (referee)
Ellipticine, an alkaloid isolated from Apocynaceae plants, exhibits significant antitumor and HIV activities. Ellipticine is a pro-drug, whose pharmacological and genotoxic effects depend on activation by cytochromes P450 (CYP) and peroxidases (Px) to a reactive species generating DNA adducts. To elucidate contribution of CYPs (and which of them) and Px to ellipticine activation, we used rat and mouse models, mice with deleted gene of NADPH:CYP reductase in the liver, thus absenting this enzyme in the liver (HRNTM ) and a control mouse line (WT), rats treated with ellipticine, and microsomal systems isolated from the liver of mouse lines and from the liver, kidney and lung of rats. The purified enzymes, CYP1A1 and 3A4, reconstituted with NADPH:CYP reductase were also used. The effect of cytochrome b5, a facultative component of the mixed function monooxygenase system, on ellipticine oxidation by CYP1A1 and 3A4 was also investigated. Carcinogenic benzo(a)pyrene (BaP), known to covalently bind to DNA after its activation with CYPs, was investigated for its potential to generate DNA adducts and to induce CYP and NADPH:CYP reductase enzymes in mouse livers. We investigated an influence of each of components of the mixed function oxidases (MFO) system on metabolism of BaP. CYP1A1 is widely accepted to be the...
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Volatilization of inorganic chlorides by haloperoxidases of soil microorganisms and plants
Loukotová, Šárka ; Stiborová, Marie (advisor) ; Moserová, Michaela (referee)
Biogeochemical cycle of chlorine, particularly formation of organically bound chlorine (Clorg), is still known only in outlines. In continental ecosystems chloride acts as stress factor, and also as source of chlorine; it originates from precipitation, which comes from marine cloud masses. Clorg are formed naturally by biotical and abiotical way. The biological factors are microorganisms, soil enzymes, plants and even animals. Halogenation processes undergo in marine environment as well, the main difference is the presence of bromine besides chlorine, therefore the reaction and formation of brominated compounds. One group of Clorg represents volatile chlorinated hydrocarbons (VOCl). Several VOCl can react with atmospheric ozone, consequently causing its depletion. The best known sources of VOCl are soil, the microorganisms living in it, and their exoenzymes released into it. The heme peroxidases in the group EC 1.11.1.X can perform halogenation of organic compounds. Hydrogen peroxide or organic peroxides are the substrates of this reaction in which hypochlorous acid is generated. The halogen in reactive form then carries chlorine onto the organic compound. To study enzymatic mediation of chlorination processes, we chose commercially available enzymes (chloroperoxidase from Caldariomyces fumago and...
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Transport of charged and neutral particles across the model biomembranes
Parisová, Martina ; Stiborová, Marie (advisor) ; Moserová, Michaela (referee)
This work was focused on the preparation of model stabilized phospholipid membranes formed on porous polycarbonate carrier. 1,2-dipalmitoyl-sn-glycero-3-phosphocholin was used for their formation in hydrophilic pores of polycarbonate carrier. For characterization of the formation of phospholipid layers, their changes and a study of transport processes, electrochemical impedance spectroscopy and voltammetry were used. Transport of cadmium and copper ions was studied in the presence and in the absence of ionophore calcimycin which was incorporated into the formed of phospholipid membrane. Because these ions are often bound in complexes with various substances, such as low molecular weight organic acids (LMWOAs), this work was also focused on the transport of copper and cadmium ions across the model phospholipid membranes in the presence of malic acid, citric acid and oxalic acid at different pH. Besides the use of ionophore, some pilot experiments were performed to realize the transfer of copper ions using two peptides, nisin and transportan 10. Formation of phospholipid membranes and the transport processes were characterized by two proposed electric equivalent circuits which correspond to the covered and to the uncovered polycarbobate carrier. Keywords: Phospholipids, Membranes, Ionophore, Peptid....
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Construction of vectors for heterologous expression of human cytochrome P450 1B1
Sojka, Pavel ; Martínek, Václav (advisor) ; Moserová, Michaela (referee)
The thesis was worked out in Laboratory of Molecular Carcinogenesis and Drug Development, which is focus on study of drug metabolizing enzymes including cytochromes P450. Cytochromes P450 are participating at initial phase of biotransformation of xenobiotics and endogenous substances and metabolism of several endogenous compounds, i.e. steroids. This work is focused on construction of expression vectors, based on the plasmid pET- 22b, suitable for heterologous expression of the human cytochrome P450 1B1. This enzyme is predominantly present in the endoplasmic reticulum of extra-hepatic tissues and its expression is induced by dioxins and polycyclic aromatic hydrocarbons. The human gene for cytochrome P450 1B1 was modified using PCR. The cleavage sites for restriction endonucleases were added to both ends of the gene. Another construct also contained N-terminal histidine tag to facilitate easier purification of the enzyme. Both insert and digested plasmids were verified using the agarose electrophoresis and used for ligation and transformation into competent cells (E. coli DH5. Final steps in construction was, however, not successful, probably due to low yields of DNA fragment extraction from agarose gels. Key words: cytochrome P450 1B1, carcinogenesis, plasmid, heterologous expression [In Czech]
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Interaction of proteins with bromphenol blue - possible analytical uses
Vodičková, Kateřina ; Hudeček, Jiří (advisor) ; Moserová, Michaela (referee)
The so called protein error of pH indicators is often used for protein determination in body fluids. A popular dye for this purpose is the bromophenol blue. A most common calibration standard, bovine serum albumin (or human serum albumin) is used. In this Thesis, I examined the influence of urea on the interaction between bovine serum albumin and bromophenol blue at pH 3,23. Addition of urea in amount corresponding to physiological values in urine (0,2-0,4 mol/l) does not cause changes in absorbance exceeding the experimental error (1 %); the same is true up to 4 mol/l of urea. Higher concentration of urea (6 mol/l) causes a considerable decrease of absorbance (up to 29 %), probably as a result of bovine serum albumin denaturation.
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Mechanism of tumor development and its influencing by ellipticine
Parisová, Martina ; Stiborová, Marie (advisor) ; Moserová, Michaela (referee)
Ellipticine (5.11-dimethyl-6H-pyridate [4,3-b] carbazole) is a powerful anti-cancer agent, exhibiting multiple mechanisms of action. This work describes the causes of cancer processes and summarizes the main pharmacological mechanisms and cytotoxic effects of ellipticine together with the results found in our laboratory indicating, a new mechanism of ellipticine action. Cytotoxic and mutagenic activity of ellipticine is attributed to its two mechanisms of activity ellipticine intercalation into DNA and its effectivity to inhibit topoisomerase II. Ellipticine also forms covalent DNA adducts after its oxidation with cytochromes P450 and peroxidases. Cytochromes P450 oxidize ellipticine up to five metabolites, of which 13- hydroxyellipticin, 12-hydroxyellipticin and N(2)-oxide of ellipticine are responsible for formation of two major DNA adducts. In the case of peroxidases, ellipticine is oxidized to a radical producing the ellipticine dimer and a minor ellipticine metabolite, the N(2)-oxide of ellipticine. Because of the high efficiency of ellipticine and its derivatives against various types of cancer, this coumpound is studied in detail. Its utilization for drug tangeting is a challenge for further study.
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Study of mechanism of action of anticancer drug ellipticine and its metabolism
Vejvodová, Lucie ; Stiborová, Marie (advisor) ; Moserová, Michaela (referee)
This bachelor thesis is aimed to study the mechanisms of action of anticancer drugs, their side effects, their resistance and pharmacokinetics. Anticancer alkaloid ellipticine was chosen as a model for this work. Bachelor thesis describes the metabolism of this substance in organisms and its potential to induce of drug metabolizing enzymes. An antineoplastic alkaloid ellipticine is a prodrug, whose mode of action is based mainly on DNA intercalation, inhibition of topoisomerasa II, and formation of covalent DNA adducts mediated by cytochromes P450 and/or peroxidases in target tissues. A variety cytochromes P450 oxidize ellipticine forming up to five metabolites (7-hydroxyellipticine, 9- hydroxyellipticine, 12-hydroxyellipticine, 13-hydroxyellipticine and ellipticine N2 - oxide). 7- hydroxy- and 9-hydroxyellipticine metabolites are considered to be mainly the detoxication products of ellipticine, while 12-hydroxyellipticine, 13-hydroxyellipticine and ellipticine N2 - oxide are considered to be mainly the activation products of ellipticine. The major ellipticine- derived DNA adducts are generated from these activation metabolites. These adducts were found in cancer cells in culture, such as human breast adenocarcinoma MCF-7 cells, neuroblastoma IMR-32, UKF-NB-3, and UKF-NB-4 cells and glioblastoma...
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Study of mechanism of action of anticancer drug tamoxifen and its toxic side effects
Kylarová, Salome ; Stiborová, Marie (advisor) ; Moserová, Michaela (referee)
Anti-estrogen therapy is used for treatment of hormone (estrogen) receptor positive breast cancer. The rise of this type of cancer is associated with a prolonged exposure to these hormones throughout life. Tamoxifen is one of the most used hormonal drugs, which blocks the effects of these hormones in breast cancer tissue by competitive binding to hormonal receptors. The affinity of tamoxifen to these receptors is not sufficient, therefore it has to be activated to metabolites having greater affinity, namely 4-hydroxytamoxifen and endoxifen. The formation of these intermediates is catalysed by cytochromes P450. In the second phase of its biotransformation hydroxylated metabolites of tamoxifen are primarily sulphated by sulphotransferases and eliminated from the body. In addition to these active intermediates, which inhibit the growth of breast tumor tissue, there are metabolites causing negative effects in the others. The most important metabolite is α-hydroxytamoxifen, which forms covalent DNA adducts in liver tissue of rats and endometrium of females. Tamoxifen therapy is associated with numerous side effects, but the greatest attention is focused to formation of endometrial cancer and induction of tumor's resistance to this therapy. Effects of tamoxifen therapy are dependent on the activity of...
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