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Long term sublethal stress in colonies of Saccharomyces cerevisiae deleted in WHI3
Krampotová, Ester ; Schierová, Michaela (advisor) ; Dušková, Michala (referee)
The yeast species Saccharomyces cerevisiae is a suitable model for studying many biological processes, including adaptation to stress conditions. Over the past 40 years, multiple signaling pathways have been uncovered to play an important role in the response to acute stress induced by high temperature, osmotic stress, or high concentrations of metals in S. cerevisiae. The effect of sublethal dose of stressor is rather neglected. The advantage of the WHI3 deletion strain used in this work is its sensitivity to the presence of stressor in the solid medium not only by reducing the growth rate but also by changing the colony morphology. The Whi3 protein stimulates not only flocculin Flo11 production but also the activity of the general transcription factors Msn2 and Msn4. The diploma project aimed to determine whether changes in the expression of genes coding for stress proteins induced by sublethal doses of the stressor were dependent on the genotype WHI3, YAP6, and MPT5. Transcription factor Yap6 and RNA binding protein Mpt5 are both involved in stress response and cause repression of FLO11. Their levels depend on Whi3. To induce mild stress, low concentrations of NaCl and CdSO4 have been applied to colonies for 4 and 6 days. Their genotype varied in the WHI3, YAP6, and MPT5 genes. Our experiments...
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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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