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Treatment and drug development against free-living pathogenic amoebae
Jankovcová, Klára-Marie ; Mach, Jan (advisor) ; Vinopalová, Martina (referee)
Free-living pathogenic amoebae are cosmopolitan unicellular eukaryotic organisms, which can cause several serious infections in humans and animals. They are causative agents of amoebic encephalitis, which are very rare and acute diseases of the central nervous system, that almost always lead to the death of the patient. Even though the importance of these pathogens has been increasing in recent years, the development of treatment procedures and drugs against them is very ineffective and unsatisfactory. Treatment and drug development is complicated mainly because of the complex biological structure of pathogens and limited knowledge of metabolic pathways and the biochemical reactions that are occurring in them, which are crucial for the development of effective drugs. In this bachelor thesis I focus on the pathogenic species Naegleria fowleri, Balamuthia mandrillaris and the pathogenic genus Acanthamoeba, which is the causative agent of encephalitis and acanthamoeba keratitis. In the first part of this bachelor thesis, I generally characterize the different representatives of free- living pathogenic amoebae and describe the clinical picture of individual diseases. In the second part I address the issue of treatment. Firstly, I describe current therapeutic options and issues of the treatment of...
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Mechanistic and structural studies of the cGAS-STING signalling pathway
Vavřina, Zdeněk ; Maloy Řezáčová, Pavlína (advisor) ; Hudeček, Jiří (referee) ; Kolenko, Petr (referee)
The cyclic GMP-AMP synthase (cGAS) - stimulator of interferon genes (STING) signalling pathway plays a crucial role in the innate immune system. It is activated by pathogen double-stranded DNA (dsDNA) or cyclic dinucleotides, which are secondary messengers of bacteria. This activation leads to the expression of type I interferons and proinflammatory cytokines. The present dissertation examines the interaction between cGAS and its substrates and the relation between the STING protein and its agonists from a mechanistic and structural point of view. The enzyme cGAS is a metazoan intracellular sensor of dsDNA. Upon its binding to DNA, it synthesizes the cyclic dinucleotide 2′,3′-cGAMP, which activates the adaptor protein STING. Besides 2′,3′-cGAMP, STING can also be activated by 3′,3′-cyclic dinucleotides that serve as secondary messengers in bacteria. We investigated various dinucleotide cyclases to better understand their substrate specificity and utilized them for the preparation of novel cyclic dinucleotides activating STING. As the most appropriate for the preparation of 2′,3′-cyclic dinucleotides, we identified mouse cGAS. Additionally, we utilized the enzymes DncV from Vibrio cholerae and DisA from Bacillus thuringiensis for the synthesis of 3′,3′-cyclic dinucleotides. These enzymes exhibit...
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Ames test in the drug development
Klaučová, Martina ; Pávek, Petr (advisor) ; Konečná, Klára (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Martina Klaučová Supervisor: prof. PharmDr. Petr Pávek, Ph.D. Consultant: PharmDr. Ivona Pávková, Ph.D. Diploma thesis title: Ames test in the drug development Background: Thesis objective is the determination of potential genotoxicity of newly developed drugs within primary testing and the introduction of the Ames microfluctuation test which can be used in common laboratory conditions. Methods: I used commercially supplied kit based on the principles of Ames test which detects reverse mutation through colour changes of the samples using bacterial strains S. typhimurium. At first I had to study literary sources and then I could design the procedures of the Ames microfluctuation test, preparation of the chemicals and storage of the strains which are optimal for all laboratories. Results: The drug samples T6445 and T6447 with 30 µM concentration tested by metabolic activation S9 on bacterial strain ST TA 98 show genotoxicity. The sample UOCHB1 with 30 µM concentration tested without activation shows possible genotoxicity on both strains ST TA 98 and ST TA 100. Other samples do not show any toxicity. I used 3 different procedures during the designation of assay. The most suitable version of the...
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Ames test in the drug development
Klaučová, Martina ; Pávek, Petr (advisor) ; Konečná, Klára (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Martina Klaučová Supervisor: prof. PharmDr. Petr Pávek, Ph.D. Consultant: PharmDr. Ivona Pávková, Ph.D. Diploma thesis title: Ames test in the drug development Background: Thesis objective is the determination of potential genotoxicity of newly developed drugs within primary testing and the introduction of the Ames microfluctuation test which can be used in common laboratory conditions. Methods: I used commercially supplied kit based on the principles of Ames test which detects reverse mutation through colour changes of the samples using bacterial strains S. typhimurium. At first I had to study literary sources and then I could design the procedures of the Ames microfluctuation test, preparation of the chemicals and storage of the strains which are optimal for all laboratories. Results: The drug samples T6445 and T6447 with 30 µM concentration tested by metabolic activation S9 on bacterial strain ST TA 98 show genotoxicity. The sample UOCHB1 with 30 µM concentration tested without activation shows possible genotoxicity on both strains ST TA 98 and ST TA 100. Other samples do not show any toxicity. I used 3 different procedures during the designation of assay. The most suitable version of the...
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Ames test in the drug development
Klaučová, Martina ; Pávek, Petr (advisor) ; Konečná, Klára (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Martina Klaučová Supervisor: prof. PharmDr. Petr Pávek, Ph.D. Consultant: PharmDr. Ivona Pávková, Ph.D. Diploma thesis title: Ames test in the drug development Background: Thesis objective is the determination of potential genotoxicity of newly developed drugs within primary testing and the introduction of the Ames microfluctuation test which can be used in common laboratory conditions. Methods: I used commercially supplied kit based on the principles of Ames test which detects reverse mutation through colour changes of the samples using bacterial strains S. typhimurium. At first I had to study literary sources and then I could design the procedures of the Ames microfluctuation test, preparation of the chemicals and storage of the strains which are optimal for all laboratories. Results: The drug samples T6445 and T6447 with 30 µM concentration tested by metabolic activation S9 on bacterial strain ST TA 98 show genotoxicity. The sample UOCHB1 with 30 µM concentration tested without activation shows possible genotoxicity on both strains ST TA 98 and ST TA 100. Other samples do not show any toxicity. I used 3 different procedures during the designation of assay. The most suitable version of the...
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Structural and functional analysis of cathepsin B1 from the blood fluke, Schistosoma mansoni
Jílková, Adéla ; Mareš, Michael (advisor) ; Obšil, Tomáš (referee) ; Mikeš, Libor (referee)
Schistosomiasis is a serious infectious disease that afflicts over 200 million people in tropical and subtropical regions. It is caused by Schistosoma blood flukes that live in human blood vessels and obtain nutrients from host hemoglobin, which is degraded by digestive proteases. Current therapy relies on a single drug and concern over resistance necessitates new drug development. In Schistosoma mansoni, cathepsin B1 (SmCB1) is a critical digestive protease that is a target molecule for therapeutic interventions. This thesis provides a comprehensive characterization of SmCB1 focused on structure-activity relationships and inhibitory regulation based on six crystal structures solved for SmCB1 molecular forms and complexes. SmCB1 is biosynthesized as an inactive zymogen in which the N-terminal propeptide operates as a natural intra-molecular inhibitor by blocking the active site. Detailed biochemical and structural analyses have identified a new and, so far, unique mechanism of SmCB1 zymogen activation through which the propeptide is proteolytically removed and the regulatory role of glycosaminoglycans in this process has been described. A study of SmCB1 proteolytic activity has revealed that the enzyme acts in two modes, as endopeptidase and exopeptidase, which makes it an efficient tool for host...
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