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Comparative study of Trichomonas vaginalis strains with various level of metronidazole resistance
Havelka, Michal ; Tachezy, Jan (advisor) ; Kopáček, Petr (referee)
Trichomonas vaginalis is an anaerobic protozoan that causes the human disease trichomoniasis. The most commonly used drug against trichomoniasis is metronidazole. Metronidazole is highly effective, yet in some cases T. vaginalis is resistant to this drug. In T. vaginalis, we distinguish resistance to metronidazole into two types based on the conditions in which it occurs, aerobic and anaerobic resistance. Both types of resistance are associated with changes in the physiology of the parasite. The aim of this study was to characterize the changes in hydrogenosome and cytosol associated with metronidazole resistance at the proteome level in aerobically resistant clinical isolates, the aerobically resistant line MR3 and the anaerobically resistant line MR100. A further aim of this work was to characterize the function of hybrid- cluster protein and to clarify its role in resistance to metronidazole since its production is more abundant in both aerobically and anaerobically resistant T. vaginalis. This work contributed to identification of several potential proteins that could play a role in the development of metronidazole resistance and established a foothold for further metabolomic and biochemical studies of metronidazole resistant T.vaginalis.
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Anaerobic fungi and herbivores
Pristašová, Paulína ; Tachezy, Jan (advisor) ; Hrdý, Ivan (referee)
Anaerobic fungi Neocallimastigomycotina participate in rumen symbiotic microbiome. This highly specific group of fungi are a part of the basal lineages of the Fungi kingdom, differing from their aerobic counterparts in many aspects, including the possession of hydrogenosomes and the production of cellulosomes. Their entire life cycle occurs in the rumen, comprising of motile zoospores, which after colonizing plant biomass, germinate into vegetative thallus, forming a sporangium. In the rumen ecosystem, anaerobic fungi are primary colonizers of ingested plant biomass, where with the help of extracelullar multienzyme complexes- cellulosomes- degrade recalcitrant plant cell wall. The ability to form cellulosomes, until now observed in prokaryots only, was acquired by horizontal gene transfer from rumen symbiotic bacteria. Their long coevolution also led to many syntrophic interactions with methanogens, which utilise H2 produced by fungal hydrogenosomes. Their potential use in biotechnology includes biogas production and increased digestibility of agricultural feed. Key words: anaerobic fungi, rumen, hydrogenosome, cellulosome
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Mitochondrion of Trimastix pyriformis
Novák, Lukáš ; Hampl, Vladimír (advisor) ; Kolísko, Martin (referee)
2013 DIPLOMOVÁ PRÁCE Lukáš Novák Abstract Free-living microaerophilic protist Trimastix pyriformis is closely related to oxymonads which are the largest eukaryotic group without any known mitochondrion. In contrast to oxymonads, an enigmatic reduced mitochondrion has been found in the cell of T. pyriformis. In EST data of T. pyriformis, a number of genes has been identified whose products are putatively localized in the mitochondrion. Among these are genes for all the components of the glycine cleavage system, [FeFe]hydrogenases and the mitochondrial marker Cpn60. We performed experiments in order to determine the cellular localization of these proteins. Our results show that the glycine cleavage system is localized in the mitochondrion. Results of the experiments carried out in order to localize two hydrogenases suggest also the mitochondrial localization but are not fully convincing. The attempt to localize Cpn60 has failed. We have also identified a set of new genes in transcripts of T. pyriformis and Monocercomonoides sp. (Oxymonadida). These genes code for some components of the SUF system of FeS cluster synthesis and a peroxidase rubrerythrin. Key words: Trimastix, Monocercomonoides, mitochondrion, hydrogenosome, mitosome, hydrogenase, glycine cleavage system, SUF system.
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Resistance of Trichomonas vaginalis and other anaerobic pathogens to metronidazole
Havelka, Michal ; Tachezy, Jan (advisor) ; Rada, Petr (referee)
The aim of this bachelor thesis is to desbribe mechanisms of resistance to metronidazole in three anaerobic eukaryotic pathogens (T. vaginalis, G. intestinalis, E. histolytica). Diseases caused by these pathogens belong to the list of important but currently neglected diseases. Metronidazole acts only on microbes with an anaerobic metabolism. The drug enters the cell by passive diffusion and needs to be activated by reduction of the nitro group. Mechanisms of activation are different for every pathogen. Enzymes bound with energetic metabolism in hydrogenosomes, cytosolic thioredoxin reductase and nitroreductases play a major role in the activation. The drug damages cells in three ways - DNA damage, formation of covalent bonds with proteins, and covalent bonds with thiols. Pathogens have specific mechanisms to defend themselves against the drug. They can either down-regulate enzymes that activate metronidazole, reduce it to non-reactive aminoimidazole or they can increase the intracellular concentration of oxygen which leads to deactivation of the drug by futile cycling. These mechanisms are bound with physiological changes and subsequently with lowered viability of these pathogens. Furazolidone and benzimidazole derivatives are the best candidates to become an alternative to metronidazole for the...
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Mitochondrion of Trimastix pyriformis
Novák, Lukáš ; Hampl, Vladimír (advisor) ; Kolísko, Martin (referee)
2013 DIPLOMOVÁ PRÁCE Lukáš Novák Abstract Free-living microaerophilic protist Trimastix pyriformis is closely related to oxymonads which are the largest eukaryotic group without any known mitochondrion. In contrast to oxymonads, an enigmatic reduced mitochondrion has been found in the cell of T. pyriformis. In EST data of T. pyriformis, a number of genes has been identified whose products are putatively localized in the mitochondrion. Among these are genes for all the components of the glycine cleavage system, [FeFe]hydrogenases and the mitochondrial marker Cpn60. We performed experiments in order to determine the cellular localization of these proteins. Our results show that the glycine cleavage system is localized in the mitochondrion. Results of the experiments carried out in order to localize two hydrogenases suggest also the mitochondrial localization but are not fully convincing. The attempt to localize Cpn60 has failed. We have also identified a set of new genes in transcripts of T. pyriformis and Monocercomonoides sp. (Oxymonadida). These genes code for some components of the SUF system of FeS cluster synthesis and a peroxidase rubrerythrin. Key words: Trimastix, Monocercomonoides, mitochondrion, hydrogenosome, mitosome, hydrogenase, glycine cleavage system, SUF system.
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