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Long term sublethal stress in colonies of Saccharomyces cerevisiae deleted in WHI3
Krampotová, Ester ; Schierová, Michaela (advisor) ; Dušková, Michala (referee)
This diploma thesis is devoted to the topic of the development of natural non-pathogenic yeast colonies in non-laboratory diploid strain of Saccharomyces cerevisae with deletion WHI3, during long-term mild stress. The absence of Whi3 causes significantly higher senzitivity to medium composition relative to the parental strain, thus whi3Δ /whi3Δ colonies are a good model for study of the virulence induction due to environmental stress in pathogenic yeasts. Deletion of WHI3 in the BR-F strain results in a significant suppression of the ability to form structured colonies caused mainly by the reduced level of Flo11. The absence of Whi3 also has a negative effect on the expression of other genes involved in the stress response. The aim of the work is to determine whether changes in the expression of genes encoding stress proteins induced by sublethal doses of the inhibitor are dependent on Whi3, Yap6 and Mpt5 proteins. To induce stress in yeast, we used NaCl or CdSO4. The YAP6 and MPT5 genes encode regulatory proteins involved in the stress response, which expression is under control of Whi3. In whi3Δ /whi3Δ , the level of Hsp26, Tsa1, Pab1, and Gre2 was lower than in the parental strain. The Yap6 protein affects the response to the presence of Cd2+ in the medium, although according to SGD, only its...
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Biochemical and molecular basis of specific properties of non-conventional osmotolerant yeast
Dušková, Michala
Unicellular organisms such as yeasts are permanently exposed to environmental changes, especially to changes of the concentration of osmotically active substances. Yeast species, which are able to cope with these changes properly, are called osmotolerant (Zygosaccharomyces rouxii, Pichia sorbitophila, Debaryomyces hansenii, etc.). The osmotolerance of yeasts depends on many physiological parameters but the most important is the efficient metabolism of internal osmolytes. This role is played by the small molecule of glycerol in most yeast species. Yeasts have to release the surplus of glycerol during the hypoosmotic shock. On the other hand, the hyperosmotic conditions require synthesis and accumulation of this small compound in a high quantity. The model yeast Saccharomyces cerevisiae has two systems transporting glycerol. First of them is the ScFps1 channel which is important mainly for releasing of glycerol during hypoosmotic shock. The second transporter, called ScStl1, is employed in accumulation of glycerol in case of hyperosmotic conditions. Detailed study of physiological properties of the three above mentioned species was performed within this work. Although they do not differ in basic morphological parameters from S. cerevisiae, their difference lies in the ability to survive desiccation,...
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Biochemical and molecular basis of specific properties of non-conventional osmotolerant yeast
Dušková, Michala
Unicellular organisms such as yeasts are permanently exposed to environmental changes, especially to changes of the concentration of osmotically active substances. Yeast species, which are able to cope with these changes properly, are called osmotolerant (Zygosaccharomyces rouxii, Pichia sorbitophila, Debaryomyces hansenii, etc.). The osmotolerance of yeasts depends on many physiological parameters but the most important is the efficient metabolism of internal osmolytes. This role is played by the small molecule of glycerol in most yeast species. Yeasts have to release the surplus of glycerol during the hypoosmotic shock. On the other hand, the hyperosmotic conditions require synthesis and accumulation of this small compound in a high quantity. The model yeast Saccharomyces cerevisiae has two systems transporting glycerol. First of them is the ScFps1 channel which is important mainly for releasing of glycerol during hypoosmotic shock. The second transporter, called ScStl1, is employed in accumulation of glycerol in case of hyperosmotic conditions. Detailed study of physiological properties of the three above mentioned species was performed within this work. Although they do not differ in basic morphological parameters from S. cerevisiae, their difference lies in the ability to survive desiccation,...
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Biochemical and molecular basis of specific properties of non-conventional osmotolerant yeast
Dušková, Michala ; Sychrová, Hana (advisor) ; Malcová, Ivana (referee) ; Janderová, Blanka (referee)
Unicellular organisms such as yeasts are permanently exposed to environmental changes, especially to changes of the concentration of osmotically active substances. Yeast species, which are able to cope with these changes properly, are called osmotolerant (Zygosaccharomyces rouxii, Pichia sorbitophila, Debaryomyces hansenii, etc.). The osmotolerance of yeasts depends on many physiological parameters but the most important is the efficient metabolism of internal osmolytes. This role is played by the small molecule of glycerol in most yeast species. Yeasts have to release the surplus of glycerol during the hypoosmotic shock. On the other hand, the hyperosmotic conditions require synthesis and accumulation of this small compound in a high quantity. The model yeast Saccharomyces cerevisiae has two systems transporting glycerol. First of them is the ScFps1 channel which is important mainly for releasing of glycerol during hypoosmotic shock. The second transporter, called ScStl1, is employed in accumulation of glycerol in case of hyperosmotic conditions. Detailed study of physiological properties of the three above mentioned species was performed within this work. Although they do not differ in basic morphological parameters from S. cerevisiae, their difference lies in the ability to survive desiccation,...
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