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Trk1 Potassium Importers - key transport systems for yeast cell fitness and stress tolerance
Masaryk, Jakub ; Sychrová, Hana (advisor) ; Heidingsfeld, Olga (referee) ; Malínský, Jan (referee)
One of the key prerequisites for yeast cell growth is the uptake of essential compounds, such as potassium. Potassium is a vital monovalent cation and its sufficient intracellular concentration is crucial for various processes, for instance: regulation of membrane potential and cell turgor, enzymatic activity, and protein synthesis. A sufficient internal concentration of potassium is also one of the pivotal signals for cell division. However, as also excess of potassium might lead to unfavourable physiological consequences in yeast, such as deacidification of vacuoles and depolarization of plasma membrane, it is imperative for the yeast cells that the whole process of potassium acquisition is a tightly regulated affair, in order to maintain proper potassium homeostasis. In yeast Saccharomyces cerevisiae, uniporter Trk1 is considered a key player in potassium uptake. The presented thesis aimed to provide novel knowledge regarding Trk1, more specifically to study its ability to modify its capacity for potassium uptake, putative regulation by phosphorylation, and involvement in the survival of glucose-induced cell death (GICD). Additionally, potassium-uptake systems in selected non-conventional species were characterized as well. The most distinctive feature of Trk1 is its alleged ability to switch...
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Alakali-metal-cation homeostasis in pathogenic Candida species
Elicharová, Hana ; Sychrová, Hana (advisor) ; Heidingsfeld, Olga (referee) ; Půta, František (referee)
Several tens of Candida species belong to the opportunistic human pathogens capable of inducing life-threatening infections in immunocompromised patients. Virulence of single Candida species depends among others on their resistance to the variable external conditions. The maintenance of alkali-metal-cation homeostasis, which means the ability to accumulate sufficient amount of potassium cations and on the other hand to survive under high extracellular concentrations of alkali-metal cations, is essential for growth and virulence of Candida cells. We observed the negative effect of fluconazole (FLC) on salt-tolerance of six Candida species and found that it is independent of the species level of FLC- resistance. FLC hyperpolarizes plasma membrane of Candida cells and therefore increases non-specific uptake of alkali-metal cations which results in strongly increased salt-sensitivity of Candida cells. The FLC-induced hyperpolarization also results in an increased sensitivity of Candida cells to the antifungals which are positively charged and are driven into the cells by the membrane potential. The effect of fluconazole on membrane potential and thus on the uptake of alkali- metal cations into the cell turned our attention to the homeostasis of potassium cations whose high intracellular concentration is...
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The role of transport systems for potassium cations in the physiology of Saccharomyces cerevisiae yeast
Marešová, Lydie ; Sychrová, Hana (advisor) ; Pácha, Jiří (referee) ; Janderová, Blanka (referee)
[n this work, we present the characteristics of kha 1 6,. strains in the background of various multiple mutations in genes encoding alkali-metal-cation transporters. Two main phenotype manifestations of the khal deletion were growth defect on high externa\ pH and hygromycin sensitivity. The correlation between these phenotypes and the kha 1 deletion was confirmed by plasmid complementation. Fluorescence microscopy of GFP-tagged Kha 1 p showed that this antiporter is localized preferentially intracellu\arly (in contrast to the plasma-membrane Na+/H+ antiporter Nha 1 p). Based on these findings, Kha 1 p is probably not localized in plasma membrane and do es not mediate efflux of alkali metal cations from cells (as published before in RammÍrez el aJ., 1998), but is important for the regulation of intracelular cation homeostasis and optima\ pH contro l, similarly as the Nhx l p. The khal deletion phenotypes were complemented by heterologous expression of a plant antiporter AtChx 17, showing that the proteins AfChx 17 and SeKhal could have similar ťunction and that S cerevisiae khal deletion mutants could serve for heterologous expression and characterization of some plant transporters in yeast, especially those localized intracellularly. We also showed that the presence of the Tokl channel strongly infl uences...
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Phenotypes of Saccharomyces cerevisiae cells lacking Isw2 chromatin remodelling factor
Frýdlová, Ivana ; Hašek, Jiří (advisor) ; Janderová, Blanka (referee) ; Sychrová, Hana (referee)
8 SUMMARY nd invasive growth. We showed that this phenotype is caused by de-repression that ncentrations of pheromone. Detailed analysis however uncovered some differences birth scar, rea that is commonly prohibited for budding. Based on our microarray data and double eletion mutant analyses, we identified one gene that is responsible for this phenotype. w2Δ cells as well as rth-scar phenotype as well as CWI pathway activation. These data prove, that de-regulation of expression of the daughter cell-specific gene DSE1 is The non-essential Saccharomyces cerevisiae protein Isw2 is a subunit of the ATP- dependent chromatin remodelling complex Isw2 that regulates the structure of chromatin, and thus plays an important role in regulation of transcription. Absence of the Isw2p induces the α-mating type-specific aberrant "shmoo-like" morphology a of a-specific genes in MATα cells and production of inappropriate a-factor which in turn activates the pheromone response pathway of isw2Δ MATα cells. Our results showed isw2Δ MATα cells can express the MATa-specific genes at the level which enables them to mate with other MATα cells. Invasion of isw2Δ MATα cells depends neither on the cell surface protein Flo11, nor on the invasive growth-specific transcription factor Tec1. On the other hand it requires components of the...
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Differentiation of yeast colonies: The role of selected transcription factors and metabolic proteins
Plocek, Vítězslav ; Palková, Zdena (advisor) ; Heidingsfeld, Olga (referee) ; Sychrová, Hana (referee)
5 Abstract Although yeasts are unicellular microorganisms, they form complex multicellular formations such as biofilms and colonies under natural conditions. Within these structures, processes such as cell differentiation, specialization by particular cell populations and cell signalling, which are typical of multicellular organisms, take place. The literature introduction to this thesis summarizes current knowledge regarding the development of biofilms and colonies, in particular those of the model organism, Saccharomyces cerevisiae, and some selected regulations that are important for the formation of multicellular structures. In the results section, I focus on two lines of research. The first is directed towards mechanisms, involved in the formation of multicellular structures. In studying the formation of SLI biofilms (biofilms at the solid/liquid interface), we have documented the antagonistic role of the regulators CYC8 and TUP1 in their formation and have also described the effect of the presence of glucose on the development and stability of SLI biofilms of strain BR-F. During this study we[D1] have developed an imaging method that allows us to prepare and observe the internal structure (vertical cross-section) of SLI biofilms, as well as the growth of unattached cells, under physiological...
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Vliv stárnutí populace na spotřebu a životní úroveň
Sychrová, Hana
Sychrová, H. The impact of people ageing on consumption and living standards. Diploma thesis. Brno: Mendel University, 2018. The diploma thesis deals with ageing of population and its impact on consumption and living standard in the Czech republic. The thesis explores the selected indicators of living standard and compares development of incomes and spending of individual generations. In the thesis, there are used techniques of marketing research, specifically questionnaire and in-depth interviews. The output of the thesis is to evaluate living standard of seniors and expectation of young generations.
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The role of ABC and MFS transporters in drug resistance of pathogenic Candida yeasts
Chaun, Martin ; Sychrová, Hana (advisor) ; Půta, František (referee)
Pathogens and their hosts lead an ancient battle of survival among themselves. New strategies are constantly being developed to defeat an opponent and counter-strategy to resist to a rival. Recently, due to increased drug use, pathogens have adapted to the prevalence of these substances in the environment, and are increasingly unresponsive to drug treatment, resulting in drug resistance status. Progressively increasing drug resistance also affects the most common fungal pathogens, Candida genus. One of the mechanisms by which organisms are able to withstand the effects of toxic substances is their transport out of the cell by membrane transport proteins. These transporters are members of the ABC and MFS protein superfamily in the Candida genus. This thesis presents ABC and MFS proteins involved in drug efflux in four Candida species, namely Candida albicans, Candida glabrata, Candida parapsilosis and Candida auris.
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