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Mitochondrial structure and energetic metabolism changes in patients with Huntington's disease and in transgenic minipig model
Vanišová, Marie ; Hansíková, Hana (advisor) ; Kalous, Martin (referee) ; Mühlbäck, Alžbeta (referee)
Huntington's disease (HD) is a severe neurodegenerative disease with autosomal dominant inheritance. HD is caused by the expansion of the CAG triplet in the gene for the huntingtin protein (Htt), which leads to damage and loss of its functions. Htt is essential in the development of the nervous system, it is involved in axonal transport, regulation of mitochondrial metabolism gene expression or spermiogenesis. In HD, the nerve tissue is most significantly damaged, but pathological changes associated with the disease are detected throughout the organism. There is currently no satisfactory treatment. Mitochondrial damage has been shown to significantly affect the progression of HD in patients with HD, but the mechanisms of mitopathy and its development with all the effects on tissue physiology in HD are still not fully understood. The aim of the dissertation theses was to study mitochondrial energy metabolism impairment, mitochondrial network organization and mitochondrial ultrastructure in HD in selected tissues of patients with HD and in a minipig model transgenic for HD (TgHD). Furthermore, the effort was to find and characterize a mitochondrial biomarker of HD, which would well reflect the patient's current clinical phenotype state and it would be possible to monitor changes in its parameters...
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Sperm and ejaculate traits and their association with male fertilization success in vertebrates with internal and external fertilization
Nesvedová, Anna ; Albrecht, Tomáš (advisor) ; Svobodová, Jana (referee)
Postcopulatory sexual selection, which encompasses sperm competition and cryptic female choice, has long been an understudied or neglected component of sexual selection. However, in sexually promiscuous organisms, it can play a crucial role in mate choice. Sperm competition exerts strong selective pressure on sperm phenotypes, yet detailed intraspecific studies investigating the relationship between sperm phenotype and male fertilization success remain relatively scarce. Furthermore, selection may operate differently in organisms with external fertilization (where the female's role in influencing sperm competition outcomes is limited) versus internal fertilization (where sperm competition occurs within the female reproductive tract, and cryptic female choice can also come into play), potentially favoring different sperm characteristics. This thesis, based on research synthesis, summarizes the knowledge about sperm traits that influence male fertilization success in promiscuous organisms, with a focus on differences in sperm trait selection in organisms with internal and external fertilization. To elucidate this issue, the thesis first provides a brief overview of the morphological diversity of vertebrate sperm. It explores sperm morphology and its relationship with male fertilization success, as...
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Study of mitochondrial morphology in pancreatic β-cells depending on the presence of different types of secretagogues
Lorenc, David ; Dlasková, Andrea (advisor) ; Mráček, Tomáš (referee)
Glucose homeostasis is crucial for the proper functioning of the organism. The pancreatic β-cells, which serve as a sensor of changes in blood glucose concentration and are responsible for the adequate release of the hormone insulin, play a crucial role in its maintenance. Increased glucose concentration activates oxidative phosphorylation and subsequently increases the concentration of cellular ATP, which then indirectly stimulates insulin secretion. The process of oxidative phosphorylation is localized in the inner mitochondrial membrane, where the final stage of processing of substrate energy into ATP occurs. To make the oxidative phosphorylation process as efficient as possible, the mitochondrial network undergoes a series of morphological changes. In this work, we aimed to elucidate the effect of changes in nutrient concentration on mitochondrial morphology in a pancreatic β-cell model, the INS1E tissue line. We used as experimental conditions: 1) a high glucose concentration at which insulin secretion is maximal, 2) a low glucose concentration at which insulin secretion does not occur, and 3) the addition of α-ketoisocaproate, a leucine metabolite that amplifies insulin secretion. We first characterized the bioenergetic parameters that influence mitochondrial morphology. A decrease in glucose...
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Mitochondrial transfer and its role in regenerative properties of mesenchymal stem cells
Jaborová, Natálie ; Krulová, Magdaléna (advisor) ; Nahácka, Zuzana (referee)
Mitochondrial transfer represents a form of intercellular communication. In this process, mitochondria are delivered from the donor cell to the recipient cell through several structures. The transfer of mitochondria is observed under pathological and physiological conditions and is accompanied by specific signaling. Mitochondria uptake by injured cells promotes tissue regeneration. This bachelor thesis discusses general knowledge of mitochondrial transfer focusing on mesenchymal stem cells (MSCs) as a donor cell type. Furthermore, the regenerative effect of MSC-derived mitochondria transfer to cells damaged by various pathologies is summarized. In this regard, MSCs have significant therapeutic potential that could be used in future clinical strategies for a number of diseases. Keywords: mitochondria, transfer, mesenchymal stem cells, regeneration
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Mechanisms of iron-sulfur cluster biogenesis in eukaryotes
Temešinko, Tomáš ; Doležal, Pavel (advisor) ; Malych, Ronald (referee)
Many essential cellular proteins use iron-sulfur (Fe-S) clusters as cofactors. These proteins often serve as enzymes, components of the electron-transport chain or as intracellular sensors. Prior to the use of the cluster in a protein, it needs to be formed or created de novo. In total, four different mechanisms of Fe-S cluster biogenesis can be used by the eukaryotic cell - ISC, CIA, SUF and NIF. All of these pathways include a specific targeting system for delivering the cluster to its acceptor protein. Errors in biosynthesis ofFe-Sclustersaremostlylethalandcanleadtofailureindevelopmentofmulticellularorganisms.Despite this a better characterization of these mechanisms is needed as research is currently still in progress. This bachelor's thesis provides current information regarding the mechanisms of Fe-S clusters biogenesis in eukaryotes acquired mostly from mammalian cells, including humans, and from well-known model organisms such as Saccharomyces cerevisiae, Arabidopsis thaliana, and parasitic protist Giardia intestinalis.
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Selective screening of antiparasitic substances
Wernerová, Klára ; Mach, Jan (advisor) ; Kovářová, Julie (referee)
The mitochondrion is the key organelle of the cell. It is involved in energy metabolism, the Krebs cycle, the respiratory chain, and the formation of Fe-S clusters, which form the structure of many proteins. Therefore, disruption of the mitochondria is usually fatal to the cell, especially if it contains only one mitochondrion, as is the case in Trypanosoma brucei brucei. The T. b. brucei parasite has become the primary model organism for our study because its basic biochemical processes are already well described, including mitochondrial metabolism, and it is also easy to cultivate in the laboratory. Other model organisms we used in this study were Leishmania mexicana, Cryptococcus neoformans and Candida albicans. All these organisms are causative agents of serious diseases, and although there are drugs against them, new drugs need to be developed due to the frequent emergence of resistances. Mitochondria-targeting drugs are promising for the pharmaceutical industry. In this work, we investigate the efficacy of compounds whose structure is composed of a mitochondrial phosphonium anchor linked to a carbon chain. These substances are capable of incorporation into the mitochondrial membranes. The work not only focuses on comparing the potency of the tested substances in selected model organisms, but...
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Mitochondrial dysfunction in brain tumors
Rollerová, Kateřina ; Vaňátko, Ondřej (advisor) ; Zobalová, Renata (referee)
Brain tumors are one of the most serious pathologies of the central nervous system. Brain tumors are aggressive and very hard to treat due to the fragile nature of the nervous system, presence of blood-brain barrier and high recurrence rate. One of the hallmarks of brain tumors is mitochondrial dysfunction. Mitochondria are organelles involved in essential cellular processes, such as energy production, redox and calcium signaling, or the regulation of cell death. Structural and functional abnormalities, mutations in the mitochondrial genome and other mitochondrial dysregulations may cause disruptions in various cellular processes, such as production of reactive oxygen species, migration, proliferation, or regulation of cell death, promoting the development and/or maintenance of brain tumors. The goal of this thesis is to summarize current knowledge about mitochondrial dysfunction in brain tumors. Key words: brain tumors; mitochondria; mitochondrial dysfunction; Warburg effect; apoptosis; reactive oxygen species; isocitrate dehydrogenase
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Optimization of real-time PCR method for quantification of human mtDNA in clinical samples
LOSKOT, Martin
This bachelor thesis dealing with measuring mitochondrial DNA (mtDNA) and how is it important to pathological conditions. Mitochondria are one of the cell organelles in eukaryotic cells. They are important to energy metabolism, aging process, and apoptosis. In current studies mitochondrial dysfunctions cause mitochondrial diseases and common illnesses, for example cardiovascular diseases, brain pathology or cancer. Studies show, that copy number of mtDNA correlates with state of health and aging process. Copy number of mtDNA is often measured by ratio of mtDNA to nuclear DNA. Measuring mtDNA of peripheral blood is appropriate indicators for mitochondrial functions because decreased copy number of mtDNA correlates with decreased function of mitochondria. We don't know, how copy number of mtDNA influence on illnesses, because it doesn't still clarify. However, studies show, that copy number of mtDNA can be biomarker of control of state of health, when we take real time measurement. In the practical part of this bachelor thesis describe preparation of samples from buccal swabs and from peripheral blood. It also describes method of measuring mtDNA by real-time PCR. There is calculation of copy number of mtDNA and evaluation of our results too. As part of the measurement optimization are described differences between two methods for diagnostic of relative copy number of mtDNA.
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Molecular basis of deficit of F1Fo-ATP synthase and its impact on energy metabolism of a cell
Štufková, Hana ; Tesařová, Markéta (advisor) ; Kuncová, Jitka (referee) ; Janovská, Petra (referee)
Mitochondria's primary function is to produce energy through the process of oxidative phosphorylation. ATP synthase is a macromolecular rotary machine located in the inner mitochondrial membrane that catalyzes the synthesis of adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate (Pi). The mitochondrial disorders due to ATP synthase deficiency represent a heterogeneous group of diseases characterized by variable severity of the phenotype with onset at birth or later in life till adulthood. Mutations in both, mitochondrial or nucelar DNA encoded genes, may result in ATP synthase impairment, either isolated or combined with deficits of other complexes of oxidative phosphorylation. The aims of the thesis were to characterize TMEM70 protein, an ATP synthase assembly factor, and to analyze the impact of novel disease variants leading to ATP synthase deficiency in patients' derived samples. TMEM70 is a 21 kDa hairpin structure protein localized in the inner mitochondrial membrane, with both termini oriented into the matrix, which forms higher oligomer structures. Our results demonstrated that the absence of TMEM70 protein leads to an isolated deficiency of complex V followed in some stage by adaptive/compensatory effect of respiratory chain complexes. Different severities...
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Study of etiopathology of mitochondrial disorders
Rákosníková, Tereza ; Tesařová, Markéta (advisor) ; Pecina, Petr (referee) ; Kalous, Martin (referee)
Mitochondrial disorders are a clinically, biochemically and genetically heterogeneous group of inherited disorders with a prevalence of about 1:5 000 live births. A common sign of those disorders is disruption of mitochondrial energetic metabolism. To this day, more than 400 genes have been associated with mitochondrial disorders, but 45% of patients are still without a genetic diagnosis. Using next-generation sequencing, new candidate genes or variants are found. To confirm the causality of those newly found genes or variants, biochemical characterisation using a plethora of various methods is necessary. The first aim of this thesis was to study the function of ACBD3 protein on mitochondrial energetic metabolism in non-steroidogenic cells HEK293 and HeLa and to confirm the causality of the ACBD3 gene in a patient with combined oxidative phosphorylation (OXPHOS) deficit. The second aim was to confirm the causality of two novel variants in MT-ND1 and MT-ND5 genes, which encode structural subunits of complex I (CI) of the respiratory chain. The third aim of the thesis was to study the formation of supercomplexes (SCs) in patients with rare metabolic diseases. Using functional studies, we showed in this thesis that ACBD3 protein has no essential function in mitochondria but plays an important role in...
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