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Cell wall integrity signalling pathway and yeast colony morphology
Reslová, Gabriela ; Schierová, Michaela (advisor) ; Seydlová, Gabriela (referee)
In the yeast Saccharomyces cerevisiae, stress on the cell wall is caused by various external influences (e.g. exposure to chemicals, oxidative stress, osmotic changes, pH changes or heat shock) which trigger the cell wall integrity signalling pathway (CWI). The aim of my work was to investigate the effect of the CWI pathway on yeast colony morphogenesis. Using strains with deletions in genes of the CWI pathway derived from two parental strains BR-F-Flo11p-GFP and PORT, I have found that differences in genetic background influences the process and activation of this pathway. Among the strains derived from BR-F-Flo11p-GFP, only the strain with the deletion of MID2 affects the appearance of colonies. MID2 encodes a cell-surface sensor of CWI pathway. In all deletion strains derived from PORT, the disruption of the CWI pathway causes a slower development of colonies growing on glycerol medium supplemented with 0,05 mM selenate inducing fluffy colony morphology. The largest effect has deletion of gene MTL1 which also encodes a cell-surface sensor with homology to Mid2. I have confirmed that strains with deletions in genes of CWI pathway have altered sensitivity to inhibitors disrupting cell wall integrity (Calcofluor white, Congo red, zymolyase). By means of zymolyase assay, I have confirmed the...
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Phospholipid metabolism in the formation of structured yeast colonies
Pavlíčková, Martina ; Schierová, Michaela (advisor) ; Heidingsfeld, Olga (referee)
Yeasts in their natural environment form structured colonies. This allows them to better adapt to environmental conditions, but also to more easily resist various types of yeast infection inhibitors. The metabolism of phospholipids is closely related to the morphology of colonies. An important gene involved in phospholipid metabolism is INO1, which encodes inositol-3- phosphate synthase. Expression of the INO1 gene is regulated by the Opi1p negative transcription factor, which also affects a number of other genes for phospholipid metabolism enzymes, is also necessary for the expression of the FLO11 gene, encoding Flo11p, which is essential to the formation of a structured colony. The main aim of my work was to investigate the correlation between colony morphology of a natural strain of Saccharomyces cerevisiae and phospholipid metabolism. I have found that changes in INO1 gene expression and colony morphology are influenced by carbon source, selenate activity and the inhibitor of β-oxidation, 2-bromooctanoic acid. Although the INO1 gene is not essential for cell viability, its deletion or overexpression causes changes in phospholipid metabolism and colony morphology. Selenate and 2-bromooctanoic acid also alter expression of the FLO11 gene, which is reflected in colony structure. Thus, 2-...
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Phospholipid metabolism in the formation of structured yeast colonies
Pavlíčková, Martina ; Schierová, Michaela (advisor) ; Heidingsfeld, Olga (referee)
Yeasts in their natural environment form structured colonies. This allows them to better adapt to environmental conditions, but also to more easily resist various types of yeast infection inhibitors. The metabolism of phospholipids is closely related to the morphology of colonies. An important gene involved in phospholipid metabolism is INO1, which encodes inositol-3- phosphate synthase. Expression of the INO1 gene is regulated by the Opi1p negative transcription factor, which also affects a number of other genes for phospholipid metabolism enzymes, is also necessary for the expression of the FLO11 gene, encoding Flo11p, which is essential to the formation of a structured colony. The main aim of my work was to investigate the correlation between colony morphology of a natural strain of Saccharomyces cerevisiae and phospholipid metabolism. I have found that changes in INO1 gene expression and colony morphology are influenced by carbon source, selenate activity and the inhibitor of β-oxidation, 2-bromooctanoic acid. Although the INO1 gene is not essential for cell viability, its deletion or overexpression causes changes in phospholipid metabolism and colony morphology. Selenate and 2-bromooctanoic acid also alter expression of the FLO11 gene, which is reflected in colony structure. Thus, 2-...
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The effect of HAc1p on the development of yeast colony
Maršíková, Jana ; Schierová, Michaela (advisor) ; Pichová, Iva (referee)
On solid surfaces wild strains of Saccharomyces cerevisiae form biofilm-like, structured colonies enabling them to survive long-term in hostile environments in the wild. However, the molecular mechanisms underlying the spatio-temporal development of colonies and their resistance to hostile conditions are still largely unknown. In this study, we analyzed the effect of the HAC1 gene on the colony morphology of wild strains of S. cerevisiae. The transcription factor Hac1p activates the unfolded protein response (UPR), which leads to activation of the expression of genes encoding components of the protein secretory pathway, and genes involved in stress responses in the endoplasmic reticulum (ER). The impact of HAC1 deletion is significant even under non-stress conditions and causes a radical reduction of structured colony architecture in hac1∆ strains derived from two wild S. cerevisiae strains (PORT and BR-F-Flo11p-GFP) and one laboratory ΣSh strain forming semi-fluffy or fluffy colonies. The hac1∆ strains exhibit a decreased vegetative growth rate, reduced cell attachment to the agar and an ineffective cell-cell adhesion resulting in decreased flocculation. The hac1∆ strains derived from BR-F-Flo11p-GFP contain a low level of Flo11p surface adhesin which is considered very important for the proper...
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Cell wall integrity signalling pathway and yeast colony morphology
Reslová, Gabriela ; Schierová, Michaela (advisor) ; Seydlová, Gabriela (referee)
In the yeast Saccharomyces cerevisiae, stress on the cell wall is caused by various external influences (e.g. exposure to chemicals, oxidative stress, osmotic changes, pH changes or heat shock) which trigger the cell wall integrity signalling pathway (CWI). The aim of my work was to investigate the effect of the CWI pathway on yeast colony morphogenesis. Using strains with deletions in genes of the CWI pathway derived from two parental strains BR-F-Flo11p-GFP and PORT, I have found that differences in genetic background influences the process and activation of this pathway. Among the strains derived from BR-F-Flo11p-GFP, only the strain with the deletion of MID2 affects the appearance of colonies. MID2 encodes a cell-surface sensor of CWI pathway. In all deletion strains derived from PORT, the disruption of the CWI pathway causes a slower development of colonies growing on glycerol medium supplemented with 0,05 mM selenate inducing fluffy colony morphology. The largest effect has deletion of gene MTL1 which also encodes a cell-surface sensor with homology to Mid2. I have confirmed that strains with deletions in genes of CWI pathway have altered sensitivity to inhibitors disrupting cell wall integrity (Calcofluor white, Congo red, zymolyase). By means of zymolyase assay, I have confirmed the...
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