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Effect of various stress factors on mitochondrial processes of pathogenic protists
Ženíšková, Kateřina
Mitochondria perform various important functions in cells. They are the main site of energy metabolism, biosynthetic and regulatory processes, and the center of iron metabolism. Additionally, mitochondria are also the central organelle responsible for the production of potentially dangerous reactive oxygen species and possess a self-destructive arsenal capable of inducing whole-cell apoptosis. This single organelle thus controls the fate of the entire cell. Given these facts, this organelle has become the focus of interest for many scientists and pharmaceutical companies developing drugs targeting mitochondria. During evolution, unicellular parasites have evolved several mechanisms to survive, defend themselves and reproduce in the hostile environment of their host. One of these mechanisms is the ability to adapt its mitochondrial metabolism to maintain the viability of the whole cell. This work focuses on mitochondria from two different perspectives: First, concerning the phenomenon of nutritional immunity, we studied the effect of iron and copper deprivation on the mitochondria of the "brain-eating" amoeba Naegleria fowleri. Proteomic analysis of cells pre-incubated with specific chelators, together with the determination of several enzyme activities and measurements of oxygen consumption,...
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Effect of various stress factors on mitochondrial processes of pathogenic protists
Ženíšková, Kateřina ; Šuťák, Róbert (advisor) ; van Hellemond, Jaap (referee) ; Leitsch, David (referee)
Mitochondria perform various important functions in cells. They are the main site of energy metabolism, biosynthetic and regulatory processes, and the center of iron metabolism. Additionally, mitochondria are also the central organelle responsible for the production of potentially dangerous reactive oxygen species and possess a self-destructive arsenal capable of inducing whole-cell apoptosis. This single organelle thus controls the fate of the entire cell. Given these facts, this organelle has become the focus of interest for many scientists and pharmaceutical companies developing drugs targeting mitochondria. During evolution, unicellular parasites have evolved several mechanisms to survive, defend themselves and reproduce in the hostile environment of their host. One of these mechanisms is the ability to adapt its mitochondrial metabolism to maintain the viability of the whole cell. This work focuses on mitochondria from two different perspectives: First, concerning the phenomenon of nutritional immunity, we studied the effect of iron and copper deprivation on the mitochondria of the "brain-eating" amoeba Naegleria fowleri. Proteomic analysis of cells pre-incubated with specific chelators, together with the determination of several enzyme activities and measurements of oxygen consumption,...
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The role of iron in the metabolism of the amoeba Naegleria gruberi
Ženíšková, Kateřina ; Konvalinka, Jan (advisor) ; Hlouchová, Klára (referee)
Iron is a biogenic trace element that is vital for all organisms on the planet Earth. This element occurs in biological systems in the form of Fe3+ and Fe2+. These two forms are often incorporated in heme structures or iron-sulfur clusters. Proteins containing iron ions have a wide range of functions in organisms. The main functions include the transport of electrons in the respiratory chain (Rieske's proteins, cytochromes), DNA synthesis (ribonucleotide reductase) and the participation in the Krebs' cycle (aconitase, succinate dehydrogenase). Naegleria gruberi is a nonpathogenic amoeba known for its pathogenic relative Naegleria fowleri. This organism causes the primary amoebic meningoencephalitis. An interesting fact about Naegleria gruberi genome is that it contains genes for both aerobic and anaerobic metabolisms. The purpose of my bachelor work was to investigate the effect of availability of iron ions on metabolism in Naegleria gruberi. Changes in the activities of enzymes from different metabolic pathways were studied including lactate dehydrogenase, isocitrate dehydrogenase, Fe- hydrogenase, aconitase and fumarase. The most significant changes were observed in the activities of alcohol dehydrogenase and Fe-hydrogenase. Key words: Iron, heme, iron-sulfur clusters, availability of iron ions,...
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Electron bifurcation - a new phenomenon in bioenergetics
Bazger, Jan ; Hrdý, Ivan (advisor) ; Ženíšková, Kateřina (referee)
Electron bifurcation is a type of enzymatic catalysis that involves the reduction of two spatially separated electron acceptors of different redox potentials by a single electron donor. A characteristic feature of this type of catalysis is the gain of a product with a higher free energy than that of the original electron donor. The energy for this endergonic reduction is obtained from a second, exergonic electron transport reaction pathway. Since 2008, when the observation of this biochemical process, previously known only from the Q-cycle in complex III, was extended by the discovery of flavin- based electron bifurcation, a total of 12 flavoproteins catalyzing this process have been described. The use of flavin-based electron bifurcation has so far been observed mainly in anaerobic prokaryotes, such as acetogens or methanogens, which live in environments with low-energy substrates. For these organisms, the possibility to reduce ferredoxin or flavodoxin, the electron acceptors of the endergonic part of the reaction, is an important physiological advantage, since these molecules can be used as electron donors for the subsequent reduction of other low-potential acceptors under favourable thermodynamic conditions. Phylogenetic analyses that give a comprehensive overview of the overall possible spread...
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Electron bifurcation - a new phenomenon in bioenergetics
Bazger, Jan ; Hrdý, Ivan (advisor) ; Ženíšková, Kateřina (referee)
Electron bifurcation is a mechanism of enzyme catalysis in which a cofactor of lower redox potential is reduced by an electron donor of higher redox potential. Since 2008, when the observation of this event, previously known only from the Q-cycle in complex III, was extended by the discovery of flavin-based electron bifurcation, a total of 12 flavoproteins have been described that catalyze this event. The use of this catalysis has so far been observed mainly in anaerobic organisms, such as methanogens or acetogens, which live in environments with low-energy substrates. For these organisms, the ability to reduce high-energy molecules, in the form of ferredoxin or flavodoxin, capable of reducing molecules whose reduction they would have to catalyze at the expense of a chemiosmotic gradient or ATP hydrolysis is a significant advantage. Phylogenetic analyses that give a comprehensive overview of the possibilities for the overall spread of flavin-based electron bifurcation among organisms are still scarce in the literature. A similar situation applies to molecular mechanisms, for most enzyme complexes, such data are not yet available.
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Methods of dramatic education and their use in education of health education
Ženíšková, Kateřina ; Kovaříková, Miroslava (advisor) ; Hanková, Zdeňka (referee)
The thesis focuses on drama education methods and their use in health education classes. The thesis defines the basic definitions of pedagogy, teacher's personality, drama education and health education. The more extensive part deals with drama education, its aims, methods and techniques. Emphasis is placed on elaboration of specific methods and techniques of drama education. The aim of this work was to find out the drama education teachers perspective on the advantages and disadvantages of the application of its methods. The research was conducted in the structured interview form. It can be stated that the research assumptions were confirmed by the research. The most used drama education methods include the playing in role method and improvisation. According to teachers, the benefits of using drama education methods are efficiency and popularity among pupils. The time requirements for implementation and the time required for preparation are the main drawbacks. Part of the thesis is a project focusing on drama education methods and their use in middle school health education class. The project deals with the basic knowledge necessary for project creation and several specific recommendations for the drama education methods used in lessons. Five specific topics are proposed and developed within this...
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Copper metabolism of Naegleria gruberi
Ženíšková, Kateřina ; Šuťák, Róbert (advisor) ; Pyrih, Jan (referee)
Copper is an important trace element, essential for all organisms. As a cofactor, it takes part in key biochemical reactions. For example, it conveys electron transfer in complex IV in the respiratory chain, functions in detoxification of hydroxyl radicals and participates on import of iron ions into the cell. Homeostasis of copper ions must be strictly regulated, to prevent their accumulation in the organism. Excess of these ions is highly toxic and can lead to cell death. Copper ions take part in reactions leading to creation of hydroxide radicals, a dangerous member of reactive oxygen species, that damages the structure of lipids, proteins and DNA. Many studies also describe the importance of copper ions in virulence, where these ions induce the immune response of the host organism. Effect of availability of copper ions on metabolism was studied on the organism Naegleria gruberi. The sequenced genome of this organism reveals, that metabolic pathways of N. gruberi are very universal. Possible flexibility of metabolism of this organism, in relation with copper ion availability, was confirmed in this work by proteomic analysis and by determining the activities of the respiration chain. Furthermore, the dependence of uptake of iron ions on copper was confirmed. Second part of this work focuses on...
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The role of iron in the metabolism of the amoeba Naegleria gruberi
Ženíšková, Kateřina ; Konvalinka, Jan (advisor) ; Hlouchová, Klára (referee)
Iron is a biogenic trace element that is vital for all organisms on the planet Earth. This element occurs in biological systems in the form of Fe3+ and Fe2+. These two forms are often incorporated in heme structures or iron-sulfur clusters. Proteins containing iron ions have a wide range of functions in organisms. The main functions include the transport of electrons in the respiratory chain (Rieske's proteins, cytochromes), DNA synthesis (ribonucleotide reductase) and the participation in the Krebs' cycle (aconitase, succinate dehydrogenase). Naegleria gruberi is a nonpathogenic amoeba known for its pathogenic relative Naegleria fowleri. This organism causes the primary amoebic meningoencephalitis. An interesting fact about Naegleria gruberi genome is that it contains genes for both aerobic and anaerobic metabolisms. The purpose of my bachelor work was to investigate the effect of availability of iron ions on metabolism in Naegleria gruberi. Changes in the activities of enzymes from different metabolic pathways were studied including lactate dehydrogenase, isocitrate dehydrogenase, Fe- hydrogenase, aconitase and fumarase. The most significant changes were observed in the activities of alcohol dehydrogenase and Fe-hydrogenase. Key words: Iron, heme, iron-sulfur clusters, availability of iron ions,...
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