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Dýchání spermií ryb: druhová specifičnost a vliv teploty prostředí
RAHI, Deepali
The presented studies were designed to investigate the role of mitochondrial respiration, glycolysis, and fatty acid oxidation in the energy supply of spermatozoa in freshwater, externally fertilizing fish species possessing differences in sperm motility duration and spawning temperature. The first study conducted on Siberian sturgeon (Acipenser baerii, Acipenseriformes) revealed that mitochondrial respiration is essential for the energy supply of spermatozoa, while glycolysis and fatty acid oxidation have minor importance at both states - before and after attaining motility. Spermatozoon oxygen consumption rate (OCR) was higher than one detected for coldwater teleosts, such as trout, and lower than in marine species, for example, turbot. The presented study also revealed that sturgeons belong to the group of fishes whose spermatozoa possess the capacity to enhance oxidative metabolism after motility activation and uncoupling of oxidative phosphorylation (OXPHOS). In the second study conducted on spermatozoa of coldwater species burbot (Lota lota, Gadiformes), the functioning of the most important bioenergetic pathways (mitochondrial respiration, glycolysis, and fatty acid oxidation) was investigated at spawning temperature (4 °C) and maximum critical temperature (CTmax, 15 °C). At spawning temperature, similar to the results revealed for Siberian sturgeon spermatozoa, the role of glycolysis and fatty acid oxidation in energy supply was insignificant. Mitochondrial respiration was detectable at both quiescent and motile states, but no inhibition was observed after exposure of sperm to the respiratory inhibitor. Also, the OCR range was the lowest compared to the available data for OCR in teleost spermatozoa at motile or immotile state. Additionally, the OCR was not enhanced after motility activation or after treatment with an uncoupling agent. Contrastingly, at CTmax, the activity of OXPHOS became predominant. The OCR was enhanced, and that could be inhibited by using a respiratory inhibitor. Furthermore, to explore the long-lasting motility of sturgeon spermatozoa, succeeding steps were taken by studying the phosphocreatine-creatine (PCr-Cr) shuttle system apart from the previously studied pathways - OXPHOS, glycolysis, and fatty acid oxidation. The results obtained for sterlet (A. ruthenus, Acipenseriformes) revealed that PCr-Cr shuttle, known for maintaining a homogenous concentration of ATP molecules throughout the flagellar length, plays an active role while spermatozoa are at a quiescent state. No significant contribution of this shuttle in energy supply after sterlet sperm motility activation was detected. In addition to this, presented results also revealed that sturgeon spermatozoa, similar to carp and trout sperm, can be reactivated after the termination of the first motility period, and these secondly activated spermatozoa can successfully fertilize eggs. Moreover, for the first time, it was revealed that OXPHOS and PCr-Cr shuttle systems are the most crucial bioenergetic pathways during the sperm reactivation process. Overall, it was concluded that in the studied fish species, despite taxonomical differences or varying spawning temperature , sperm energy production and utilization strategy remained the same: most of the spermatozoon energy was derived from stored ATP that had been synthesized via OXPHOS during a quiescent but bioenergetically active state. Also, sturgeons are the group of fishes that possess an ability of sperm reactivation, with mitochondrial respiration and PCr-Cr shuttle system being the major contributing pathways for energy supply during reactivation process.
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Importance of glycolysis and oxidative phosphorylation in the metabolism of mesenchymal stem cells
Fráňová, Markéta ; Krulová, Magdaléna (advisor) ; Rohlenová, Kateřina (referee)
Mesenchymal stem cells (MSCs) are classified as multipotent stem cells. They possess the ability to differentiate into many cell types, promote angiogenesis, increase cell survival in damaged tissue and modulate the immune response. These functions of MSCs are used in the treatment of various injuries and some diseases. This work characterizes MSCs, with a focus on their energy metabolism, specifically on the switch in their metabolic phenotype between glycolysis and oxidative phosphorylation in different states of MSCs, during cell culture and after transplantation. Finally, two modulations of MSC metabolism are presented, including cultivation in a hypoxic environment and quiescence induced by serum deprivation, which increase cell survival under the ischemic conditions that MSCs enter after transplantation. Key words: mesenchymal stem cells, metabolism, glycolysis, oxidative phosphorylation
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Metabolic alterations in cancer cells and their implications in the therapy of acute leukemias
Harárová, Alžbeta ; Starková, Júlia (advisor) ; Mrvová, Silvia (referee)
Cancer metabolism differs from that of the healthy cells in several aspects. Aerobic glycolysis (e.g. converting pyruvate to lactate under normoxic conditions) was the first described metabolic alteration of cancer cells. Metabolic alterations have since been described in the tricarboxylic acid cycle, oxidative phosphorylation, in the metabolism of amino acids (especially glutamine, asparagine and serine) and also in the metabolism of fatty acids and cholesterol. The common feature of these changes is the tendency to prefer anabolic pathways, thus enabling fast proliferation of cancer cells. The study of cancer metabolism is particularly important in the case of cancer cells that show resistance to treatment, as their aberrant metabolism is not only a potential diagnostic marker but also a potential therapeutic target. The majority of metabolic alterations have been described for the first time in solid tumors, whereas only recently has the metabolism of acute leukamias gained more attention. Asparaginase is an example of a chemotherapeutic agent that targets a metabolic alteration of leukemic cells. Distinct metabolic profile is also associated with the glucocorticoid resistance. Detailled study of the metabolic alterations of leukemic cells has elucitated the mechanisms of the asparaginase and...
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Characterization of a role of selected antiapoptotic Bcl-2 family proteins in mitochondrial metabolism.
Antoš, Šimon ; Anděra, Ladislav (advisor) ; Brábek, Jan (referee)
Proteins from the Bcl-2 family are now for over 30 years widely studied mainly for their key role in apoptosis, a principal mode of regulated cell death. In the last ten years Bcl-2 proteins were also linked to the regulation of cellular signaling, mainly cellular metabolism and respiration. In this study we aimed to analyze non-apoptotic function of Bcl-2 proteins by their genetic elimination using the CRISPR-Cas12a approach and by the subsequent analysis of mitochondrial respiration, glycolysis and metabolic profiling. Our results confirmed that Bcl-2 proteins can modulate the level of mitochondrial respiration. The elimination of anti-apoptotic proteins Bcl-2, Bcl-XL and Mcl-1 decreased high respiration of cells lacking pro-apoptotic proteins Bax and Bak to the levels observed in parental U87-MG glioblastoma cells. Therefore, the loss of anti-apoptotic Bcl-2 proteins has greatly impacted mitochondrial respiration and it points to their role in a regulation of oxidative phosphorylation.
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The role of energy metabolism in cardioprotection induced by the adaptation to chronic hypoxia
Kolář, David ; Žurmanová, Jitka (advisor) ; Adamcová, Michaela (referee) ; Bardová, Kristina (referee)
Cardiac energy metabolism is the one of the most complex system in the body. To sustain life, but also to respond quickly to any sudden changes (e.g. running, emotional stress), the heart has developed a unique ability and has become a metabolic "omnivore". At physiological conditions, long chain fatty acids (LCFAs) present the major energetic source for the adult myocardium. However, the cardiac energy metabolism may be compromised during pathophysiological states. One of the most dangerous is, undoubtedly, ischaemia-reperfusion injury with its acute form, myocardial infarction. However, the adaptation to chronic hypoxia has been known for decades for its cardioprotective effect against I/R. Changes of cardiac energy metabolism induced by the adaptation have not been fully explored and the system conceals still too many secrets. This thesis has aimed to determine how adaptation to chronic hypoxia affects the cardiac metabolism of the rat LVs in the following set-ups: 1. The effect of chronic normobaric hypoxia (CNH; 3 weeks, 5500m) during a brief I/R protocol in vitro on the protein kinase B/hexokinase (Akt/HK) pathway, including the expression and phosphorylation of Akt, the expression and localization of HK, the expression of mitochondrial creatine kinase (mtCKS), and the level of Bcl-2 family...
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The role of energy metabolism in cardioprotection induced by the adaptation to chronic hypoxia
Kolář, David
Cardiac energy metabolism is the one of the most complex system in the body. To sustain life, but also to respond quickly to any sudden changes (e.g. running, emotional stress), the heart has developed a unique ability and has become a metabolic "omnivore". At physiological conditions, long chain fatty acids (LCFAs) present the major energetic source for the adult myocardium. However, the cardiac energy metabolism may be compromised during pathophysiological states. One of the most dangerous is, undoubtedly, ischaemia-reperfusion injury with its acute form, myocardial infarction. However, the adaptation to chronic hypoxia has been known for decades for its cardioprotective effect against I/R. Changes of cardiac energy metabolism induced by the adaptation have not been fully explored and the system conceals still too many secrets. This thesis has aimed to determine how adaptation to chronic hypoxia affects the cardiac metabolism of the rat LVs in the following set-ups: 1. The effect of chronic normobaric hypoxia (CNH; 3 weeks, 5500m) during a brief I/R protocol in vitro on the protein kinase B/hexokinase (Akt/HK) pathway, including the expression and phosphorylation of Akt, the expression and localization of HK, the expression of mitochondrial creatine kinase (mtCKS), and the level of Bcl-2 family...
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Biochemical parameters of energy metabolism in cerebrospinal fluid in inflammatory and non-inflammatory CNS diseases.
Bořecká, Klára ; Fialová, Lenka (advisor) ; Bartoš, Aleš (referee) ; Matouš-Malbohan, Ivan (referee)
The basic examination of the cerebrospinal fluid provides a quick orientation in the diagnostic algorithm of CNS diseases about the nature of the pathological process. The current evaluation of cytology and biochemical parameters of glucose metabolism reports about the cells present and at the same time about the level of their activation. The aim of the work was to investigate the relationship between biochemical and cytological findings in cerebrospinal fluid in a large data set (n = 8 178), or confirm the hypothesis of a significant alteration in the Coefficient of Energy Balance (CEB) in cytological classes typically accompanying oxidative burst of phagocytes. CEB was subjected to analysis and comparison with other energy parameters (lacto-glucose ratio, gluco-lactate ratio, concentration of lactate and glucose in cerebrospinal fluid). The relationships between blood and cerebrospinal fluid glucose and lactate concentrations were investigated. CEB values were statistically significantly different in cytological groups, which reflected purulent inflammation, tumor involvement or infection by potential intracellular pathogens, the hypothesis was confirmed. Other energy parameters excluding glycorrhachia distinguish these cytological groups as well as CEB. There are inaccuracies in the derivation...
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Metabolic control of the cell cycle in bacteria
Valtová, Aneta ; Lichá, Irena (advisor) ; Fišer, Radovan (referee)
Metabolic control of cell cycle has been studied for a long time in bacteria, but it is not still fully elucitated. The mechanisms described for several decades have been described in more detail and find new connections between basic metabolism and the cell division process itself. Cell cycle regulation, depending on metabolism and nutritional conditions, takes place over all steps of the cycle. The most mechanisms are studied at the level of bacterial division formation. Nutritional deprivation induces stress responses that use low-molecular substances which are involved in signaling pathways and which regulate the cell cycle. One of the most studying is the molecule of guanosine (penta)tetraphosphate (p)ppGpp, which affects cell cycle at the level of genes expression, at the level of proteins involved in the process of creating divisome, even at the level of replication. Recent research revealed that some enzymes with their already known enzymatic function in major metabolic pathways (glycolysis and TCA), also have a function as sensors that transmit a signal about the nutritional change directly to the division apparatus of the cell. These enzymes regulate the formation of the Z ring through the protein FtsZ or its auxiliary proteins most often and have been found in Gram-positive (Bacillus...
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The role of energy metabolism in cardioprotection induced by the adaptation to chronic hypoxia
Kolář, David
Cardiac energy metabolism is the one of the most complex system in the body. To sustain life, but also to respond quickly to any sudden changes (e.g. running, emotional stress), the heart has developed a unique ability and has become a metabolic "omnivore". At physiological conditions, long chain fatty acids (LCFAs) present the major energetic source for the adult myocardium. However, the cardiac energy metabolism may be compromised during pathophysiological states. One of the most dangerous is, undoubtedly, ischaemia-reperfusion injury with its acute form, myocardial infarction. However, the adaptation to chronic hypoxia has been known for decades for its cardioprotective effect against I/R. Changes of cardiac energy metabolism induced by the adaptation have not been fully explored and the system conceals still too many secrets. This thesis has aimed to determine how adaptation to chronic hypoxia affects the cardiac metabolism of the rat LVs in the following set-ups: 1. The effect of chronic normobaric hypoxia (CNH; 3 weeks, 5500m) during a brief I/R protocol in vitro on the protein kinase B/hexokinase (Akt/HK) pathway, including the expression and phosphorylation of Akt, the expression and localization of HK, the expression of mitochondrial creatine kinase (mtCKS), and the level of Bcl-2 family...
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