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Sch9p and Rim15p signaling pathways in yeast colony development
Mikešová, Jana ; Palková, Zdena (advisor) ; Heidingsfeld, Olga (referee)
On solid surfaces, laboratory strain Saccharomyces cerevisiae BY4742 forms horizontally and vertically stratified colonies. Central part of the colony differentiates into U and L cells occupying upper and lower colony regions, respectively. There are many morphological and physiological differences between these two cell types. However, molecular mechanisms of the vertical stratification are still largely unknown. In this study, I analyzed effects of the deletion and overexpression of Sch9p a Rim15p kinases with crucial role in nutrient sensing pathways, of transcription activators Msn2p and Msn4p involved i stress response and of post-diauxic shift transcription factor Gis1p in yeast colony differentiation and U and L cell survival. Microscopic analyses showed changes in morphology of cells in colonies of these strains and decreased ability of vertical stratification in colonies of the strain rim15Δ and partially in colonies of the strain PTEF-SCH9. Moreover, changed level of these proteins significantly affected long-term survival of U and L cells. Obtained data suggest an involvement of nutrient sensing pathways in colony formation and development.
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Use of antibodies for the characterization of chromatin modifications in Saccharomyces cerevisiae
Kovaľová, Libuša ; Hodek, Petr (advisor) ; Malík, Radek (referee)
Transcription of precursor mRNA (pre-mRNA) and its splicing were originally conceived as two separate processes. Using Saccharomyces cerevisiae as a model, it was shown that the assembly of the complex catalyzing pre-mRNA splicing (spliceosome) can occur cotranscriptionally, i. e., during the time before the termination of transcription by RNA polymerase II. Research on cotranscriptional splicing revealed that proteins involved in transcription and specific chromatin modifications may affect pre-mRNA splicing and its regulation. It is also possible that spliceosome assembly and chromatin modifications can affect each other. Prp45, the yeast ortholog of the human transcription coregulator SKIP/SNW1, has been previously associated only with splicing. The results obtained in our laboratory suggest that Prp45 could be used as a regulator coupling the processes of transcription and splicing. We have shown that PRP45 has genetic interactions with factors important for transcription elongation, as well as chromatin modifications, and that it affects early stage of spliceosome assembly. The aim of this bachelor project was document the relationship between the physiological role of Prp45 and H3K4 trimethylation using chromatin immunoprecipitation. It was found that prp45(1-169) mutation does not markedly...
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Physiological role of Na+/H+ antiporters in yeast cells
Zahrádka, Jaromír ; Sychrová, Hana (advisor) ; Obšilová, Veronika (referee) ; Pichová, Iva (referee)
3 Abstract Yeast Saccharomyces cerevisiae belongs to important models for alkali-metal-cation homeostasis research. As other cells, certain intracellular content of K+ is necessary for S. cerevisiae, but Na+ or other alkali metal cations (Li+ , Rb+ ) are toxic for yeast cells. Uniporters Trk1 and Trk2 are responsible for K+ accumulation, while efflux of Na+ , Li+ , Rb+ and K+ is ensured by Ena ATPases, Na+ (K+ )/H+ antiporter Nha1 and K+ specific channel Tok1. Several regulators of K+ (Na+ ) transporters are already known, but reciprocal regulation between transporters and overall picture of the maintenance of alkali-metal-cation homeostasis is still unclear. In this work, K+ circulation (simultaneous uptake and export of K+ ) was shown to be important in alkali-metal-cation homeostasis maintenance. K+ circulation is maintained using reciprocal regulation and interactions between K+ exporters and importers. Though obtained results showed that the alkali-metal-cation homeostasis and associated physiological parameters (e.g. membrane potential, cell size, salt sensitivity) are strain specific, Nha1p was verified to be important for cell survival in ever-changing natural environment. Furthermore, two novel positive regulators of Nha1p activity were found, 14-3-3 proteins and Cka1 kinase. 14-3-3 proteins...
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Physiological role of Na+/H+ antiporters in yeast cells
Zahrádka, Jaromír
3 Abstract Yeast Saccharomyces cerevisiae belongs to important models for alkali-metal-cation homeostasis research. As other cells, certain intracellular content of K+ is necessary for S. cerevisiae, but Na+ or other alkali metal cations (Li+ , Rb+ ) are toxic for yeast cells. Uniporters Trk1 and Trk2 are responsible for K+ accumulation, while efflux of Na+ , Li+ , Rb+ and K+ is ensured by Ena ATPases, Na+ (K+ )/H+ antiporter Nha1 and K+ specific channel Tok1. Several regulators of K+ (Na+ ) transporters are already known, but reciprocal regulation between transporters and overall picture of the maintenance of alkali-metal-cation homeostasis is still unclear. In this work, K+ circulation (simultaneous uptake and export of K+ ) was shown to be important in alkali-metal-cation homeostasis maintenance. K+ circulation is maintained using reciprocal regulation and interactions between K+ exporters and importers. Though obtained results showed that the alkali-metal-cation homeostasis and associated physiological parameters (e.g. membrane potential, cell size, salt sensitivity) are strain specific, Nha1p was verified to be important for cell survival in ever-changing natural environment. Furthermore, two novel positive regulators of Nha1p activity were found, 14-3-3 proteins and Cka1 kinase. 14-3-3 proteins...
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Autophagy as a mechanism of adaptation the yeast
Zieglerová, Leona ; Váchová, Libuše (advisor) ; Zikánová, Blanka (referee)
Autophagy is a degradation pathway, conserved from yeast to mammals. The uniqueness of this pathway lies in its function, it is applied in the cell especially under the adverse conditions. It helps the cell to deliver essential nutrients for life, it removes the damaged or superfluous organelles, protein aggregates and helps with recycling and maintains a constant inner environment. These functions can prolong cell life and the cells survive the adverse conditions. Autophagy may induce the programmed cell death type II. This paper describes the basic of autophagy machinery, regulation and influence of yeast autophagy to adapt to the stressful conditions. Understanding the mechanism and regulation of autophagy in yeast may help with the study of autophagy in mammals. In mammals, this degradation pathway disorders cause many diseases (especially neurodegenerative), autophagy also effects the formation of tumors. Powered by TCPDF (www.tcpdf.org)
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The comparison of the performace of selected carbocyanine dyes in fluorescent probing of yeast cell membrane potential.
Mudroňová, Kateřina ; Plášek, Jaromír (advisor) ; Krůšek, Jan (referee)
The membrane potential is one of the most important parameters of the living cell. It can be measured using carbocyanine fluorescent probes. In this thesis we examined parameters of several dyes of this family. For further experiments three of them were chosen - diOC3(3), diIC1(3) a diIC2(5) as a supplement to diSC3(3) and diSC3(5), which represent standard probes used at biophysical department of Institut of Physics. We compared the rates of their accumulation in S. cerevisiae cells to determine if they were MDR pumps' substrates. The other goal of this work was to decide whether the results obtained using different probes are equivalent and to determine if the presence of a probe affects the spectral characteristics of another. For this purpose we have chosen diSC3(3) and diSC3(5). With those dyes we examined the influence of the acidification on membrane potencial of the yeast S. cerevisiae. We showed that the information on depolarization obtained using both probes were matching very well.
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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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Biotechnological production of selected metabolites on whey substrate
Gadová, Martina ; Kočí, Radka (referee) ; Márová, Ivana (advisor)
The submitted master thesis deals with assessment of the possibility of using of cheese whey for biotechnological production. Study content composition of lyophilized whey, optimization of acid hydrolysis and preparation of cultivating mediums with different content and treatment of cheese whey. Between the aims of this thesis belong also screening of microbial producers, interesting for biotechnology and looks at their growth and production of selected metabolites of cultivation mediums containing cheese whey. All substrates and produced metabolites where examined with UHPLC-PDA-RI and GC-FID: Amount of produced microbial lipids was determined by gravimetric analysis. Examined microorganisms belonged to yeast genus Saccharomyces, Metschnikowia and bacterial genus Lactobacillus and its focused on production of ethanol, microbial lipids and lactic acid. The highest yields with using yeasts were obtained using production medium containing hydrolysed lactose in cheese whey. The highest production, in case of bacteria, was obtained using non-hydrolysed, untreated cheese whey production medium.
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Surface Treatment of Materials for BioTechnologies
Šupák, Marek ; Slámová, Jitka (referee) ; Krčma, František (advisor)
The theoretical part focuses on the importance of yeast, its role in brewing, the need for a reliable and economically beneficial pasteurization step that would meet modern requirements. Also in this part is defined plasma, its occurrence and the use of the glass structure used in the practical part. In the first part of the experimental work, the bachelor thesis deals with the action of plasma as a means of pasteurization. Saccharomyces cerevisiae yeast was introduced into the plasma. Gradually, the period of exposure of the yeast to the plasma discharge was determined and the number of survived and dead cells monitored. The methylene blue dye was used to identify yeast viability. After staining, the yeast was monitored under a microscope and calculated. Bürker's cell was used to determine the number of yeast cells. The experiment demonstrated plasma activity as a sterilization step, due to the decreasing number of living cells and the increase in the number of dead cells in the yeast-containing sample. In the 2nd part the surface was activated in the plasma discharge. The glass thus prepared was immersed in the culture medium for 24 hours to form a layer of culture medium on the surface of the glass. The remainders of the culture medium were then discharged and a small amount of yeast in the distilled water was pipetted. After 24 hours the yeast was counted on the Bürker's cell, the yeast growth was evaluated and the plasma activation efficiency was evaluated for activation and layer formation. The method of contact angles was used to confirm the effect of plasma on the surface of the glass. In this section, we demonstrated the effect of plasma on the surface of the glass and the formation of a thin layer of nutrient medium that supplied the yeast with the necessary substances for reproduction.
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The characteristics of stress granules in yeast Saccharomyces cerevisiae
Slabá, Renata ; Hašek, Jiří (advisor) ; Binarová, Pavla (referee)
9 ABSTRACT For proper function proteins should have a native conformation. If their conformation is impaired due to environmental stress or genetic mutation, proteins become prone to aggregation. There exist various types of protein aggregates. Stable non-membraneous inclusions can form which can serve for clearance of aberrant proteins from place where they can interfere with essential cellular processes. Another type of aggregates can serve as transient deposits of proteins thus protecting them from stress conditions. Stress granules (SG) are a such example of transient granules. Their formation is induced by heat shock for example. SGs contain mRNA, components of translation machinery, and other proteins. One of these proteins is Mmi1, small highly conserved protein with unknown function. Association of Mmi1 with stress granules and partial co-localization with chaperon Cdc48 and proteasom indicates Mmi1 can mediate heat stress damaged protein degradation. We have uncovered that yeast prion protein Sup35 is a component of stress granules as well. With regard to its aggregation capability there existed an assumption that prion domain of Sup35 could serve as scaffold for SG assembly. However as we show deletion of prion domain of Sup35 protein does not affect stress granules formation dynamics. Yeast...
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