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Methods for characterization of persistent state after exposure to selected antibiotics in Staphylococcus aureus
Valtová, Aneta ; Lichá, Irena (advisor) ; Tkadlec, Jan (referee)
Staphylococcus aureus is a opportunistic pathogen that can cause severe and chronic infections. The reason of the infections relapse is often the persistence. It is about adapting to stressful conditions by inducing a dormant state, which would allow bacteria to survive exposure to antibiotics and grow again after their elimination. Bacteria that persist in the patient acquire various adaptive mutations, which are transmited creating subpopulations that have a better ability to persist. The aim of this diploma thesis was to compare individual methods of persistent study that could be used in clinical practice in the future, and at the same time to try a closer molecular characterization of the persistent state with using methods for calculating gene expression. I had chronological isolates of Staphylococcus aureus at my disposal, the initial one being the primoisolate, an isolate taken at the diagnostics of cystic fibrosis before the start of antibiotic treatment. Another was taken at a distance of three-quarters of a year and the last with a half-year interval from the previous one. Following whole genome sequencing, genes in which adaptive mutations occurred were identified. The first method determines the degree of persistence by calculating CFU (Colony Forming Units) after antibiotic treatment....
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Methods for characterization of persistent state after exposure to selected antibiotics in Staphylococcus aureus
Valtová, Aneta ; Lichá, Irena (advisor) ; Tkadlec, Jan (referee)
Staphylococcus aureus is a opportunistic pathogen that can cause severe and chronic infections. The reason of the infections relapse is often the persistence. It is about adapting to stressful conditions by inducing a dormant state, which would allow bacteria to survive exposure to antibiotics and grow again after their elimination. Bacteria that persist in the patient acquire various adaptive mutations, which are transmited creating subpopulations that have a better ability to persist. The aim of this diploma thesis was to compare individual methods of persistent study that could be used in clinical practice in the future, and at the same time to try a closer molecular characterization of the persistent state with using methods for calculating gene expression. I had chronological isolates of Staphylococcus aureus at my disposal, the initial one being the primoisolate, an isolate taken at the diagnostics of cystic fibrosis before the start of antibiotic treatment. Another was taken at a distance of three-quarters of a year and the last with a half-year interval from the previous one. Following whole genome sequencing, genes in which adaptive mutations occurred were identified. The first method determines the degree of persistence by calculating CFU (Colony Forming Units) after antibiotic treatment....
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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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Metabolic control of bacterial division.
Valtová, Aneta ; Lichá, Irena (advisor) ; Fišer, Radovan (referee)
Metabolic control of cell cycle has been study for a long time, but it is not completely known. Mechanisms of metabolic control described for a several decade has been explained on molecular level with using a modern methods. Regulation of cell cycle in consideration of metabolism and nutritional status is going on at the several level of cell replication. The most known is about assembly of bacterial cell divisiome. Changes in nutrient availability induce stress response that use low-molecular substances in signaling pathways leading to changes in the cell cycle. One of the most studied is (p)ppGpp that participates in stringent response and affect sigma factors, directly inhibits the initiation of replication by binding to the DnaG primase and indirectly inhibits the elongation of replication. Current researches has revealed that some enzymes with already known enzymatic function in the major metabolic pathways (glycolysis or TCA) also has a function as sensors that transmit the nutritional change signal directly into the cell dividing process. These signals most often inhibits FtsZ protein or affect its helper proteins and subsequent ring formation. Analogues of these enzymes were found in gram-positive (Bacillus subtilis) and gram-negative bacteria (Escherichia coli, Caulobacter crescentus)....
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