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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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Temporal accuracy of speech imitation in two age groups of children
Prachová, Pavla ; Volín, Jan (advisor) ; Palková, Zdena (referee)
The goal of this thesis was to test the ability of speech imitation in terms of temporal accuracy in two age groups of children. The first age group comprised 8 girls and 8 boys at the age of 10 to 11 years; the second group consisted of 8 girls and 8 boys at the age of 12 to 13 years. For the purpose of the experiment a perception-production test was created - it consisted of six, nine and twelve syllabic declarative sentences which contained two, three and four trisyllabic stress- groups. The task of the participating children was to repeat the sentences in three manners: in exactly the same words as they had heard them, and then by using the syllable /na/ and /ba/. Even though the children were able to meet the task, in some cases deviations occurred, such as deformations of the sentences in a certain way. Accuracy of imitation was investigated through average deviations from the model sentences. Based on the obtained values we identified the factors of length and composition of the task items and also the manner and order of imitation. We were also interested whether age and gender of respondents affect the accuracy of imitation. Key words speech rhythm, tempo, duration, stress-group, average deviation, imitation, children
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TOR signalling in yeast
Šimek, Jan ; Palková, Zdena (advisor) ; Španielová, Hana (referee)
TOR ("Target of rapamycin") protein, a highly conserved Ser/Thr protein kinase, is a central component of signalling network that controls cell growth in diverse eukaryotic organism, ranging from yeast to man. TOR proteins were first identified in yeast Saccharomyces cerevisiae in 1991 as the targets of the antifungal and immunosupressive agent rapamycine. In contrast to most eukaryotes, yeast contains two TOR homologues , Tor1p and Tor2p. These proteins are components of multiprotein complexes TORC1 and TORC2. TORC1 is specifically inhibited by rapamycine and controls cell growth in response to quality of the available nutrients. TORC2, which is insensite to rapamycine, regulates actin polymerization, sphingolipid biosynthesis and endocytosis. This work is focused on description of both TOR complexes, especially on downstream and upstream regulation of TORC1. Powered by TCPDF (www.tcpdf.org)
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Imitational Capacity of Philologically Oriented Subjects in the Domain of Speech Rhythm
Černá, Martina ; Volín, Jan (advisor) ; Palková, Zdena (referee)
The importance of rhythm for speech communication was recognised by ancient orators. Since the forties of the last century, this phenomenon has become more systematic subject of interest of Speech Sciences and there has been a rapid development in this research area in the last decade. Throughout the years concerned, however, this concept was somewhat hazy due to the context, in which it was used in some studies. This master thesis begins with a selective overview of approaches to given issue in the field of phonetic research, trying to identify their critical moments, noticing used methodology and applicability of outputs in particular. Special attention is paid to the rhythmic aspects of Czech and issues of their description. We also bring a message of selected studies, which have already been made in this respect. The aim of this work lies in the experimental study focused on assessment of philologically oriented students' ability to imitate speech rhythm according to given pattern in following modes - word by word, on the monotone syllable and by tapping. The results confirmed the hypothesis that the imitation accuracy depends on the type of repetition - the overall data show significant differences in terms of the lowest, higher and the highest deviations from the model, respectively. To a...
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Prions in yeast
Bezdíčka, Martin ; Palková, Zdena (advisor) ; Žíla, Vojtěch (referee)
The thesis describes yeast prions and their biological effects on yeast in general. It defines the basic characteristics of yeast prions, that distinguish prions from other proteins. The thesis introduces various possibilities of prion formation, and propagation as well as specific types of yeast prions, including various functions of most studied types of prions. The thesis also focuses on chaperones that affect the state of yeast prions in cells. Lastly, the thesis indicates similarities between yeast prions and mammalian prions that are related to neurodegenerative diseases. Key words: Yeast prions, features of yeast prions, chaperones, neurodegenerative disease, Saccharomyces cerevisiae
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The function of Pmp3p protein
Belovičová, Martina ; Palková, Zdena (advisor) ; Pichová, Iva (referee)
During development of Saccharomyces cerevisiae colonies on solid substrate, metabolic transitions occur, which are reflected by pH changes around the colony and also by changes in cell membrane potential. Analyses of transmemebrane potential oscillations revealed a function for Plasma Membrane Proteolipid 3 (Pmp3p) in this process. The thesis discusses possible function of Pmp3p protein mainly on the basis of direct observation of Pmp3p localization in vivo under variety of cultivation conditions. Yeast strains with different variants of Pmp3p protein fused with different protein tags that allow monitoring of Pmp3p localization and concentration in cells were prepared by homologous recombination. Localization of Pmp3p in the plasma membrane and in lipid particles was found. The Pmp3p level in cells was stable during development of colonies growing on either respirative or fermentative carbon source medium. High concentration of extracellular sodium chloride did not evoke increase in Pmp3p-GFP concentration. Key words: Pmp3p, proteolipids, UPF0057 (PMP3) family, Saccharomyces cerevisiae, long term survival, lipid particles
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Localisation of selected proteins during yeast colony development
Plocek, Vítězslav ; Palková, Zdena (advisor) ; Heidingsfeld, Olga (referee)
Yeasts is unicellular organisms which can create remarkably complex colonies. By studying multicellular structures of Saccharomyces cerevisiae yeast it was found that cells within the yeast colony behave differently. (Kamath and Bungay, 1988; Mináriková et al., 2001; Scherz et al., 2001; Palková and Váchová, 2006; Váchová et al., 2009; Piccirillo et al., 2010; Váchová et al., 2011). Through microarray analysis of the developing yeast colony (Palková et al., 2002; Váchová et al., 2009) were described genes whose expression changes basically during the development of the colony. Of those genes, I chose four - PD5, STL1, PHO89, FET3 - that , as I thought, could affect the growth and differentiation of the yeast colony. I created their fusion variants with GFP and, using techniques of yeast colony cuts, yeast colony differentiation in sucrose gradient and measuring by flow cytometry I identified places in the colony, where the gene expression occurs. I found out that in the yeast colony differentiation and different expression take place in early phases of the development.
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Structural and functional characterization of yeast plasma membrane domains
Strádalová, Vendula ; Malínský, Jan (advisor) ; Palková, Zdena (referee) ; Konopásek, Ivo (referee)
Plasma membrane (PM) of living cells hosts variety of important cellular functions that must be precisely coordinated in space and time. Recent research shows that the plasma membrane is organized into specific domains to accomplish all these tasks. Our laboratory is focused on the organization of the plasma membrane in Saccharomyces cerevisiae where several distinct lateral compartments were identified at the fluorescence microscopy level. One of them is the Membrane Compartment occupied by arginine transporter Can1 (MCC) which consists of isolated, highly stable, ergosterol enriched, 300nm patches containing specific proton symporters and proteins of unknown function (Sur7- and Nce102-like). These membrane domains are organized by cytosolic protein complexes called eisosomes, composed mainly of proteins Pil1 and Lsp1. This work is a continuation of studies that tried to elucidate the composition, structure and function of MCC. In the first section of this work we concentrated on ultrastructural characterization of MCC domains. Foremost, we developed a protocol preserving the plasma membrane ultrastructure. The comparison of cryofixed and chemically crosslinked cells clearly showed that cryofixation by high pressure freezing together with freeze substitution and low temperature resin embedding...
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Molecular mechanisms of formation and development of colonies of wild Saccharomyces cerevisiae strains
Šťovíček, Vratislav ; Palková, Zdena (advisor) ; Hašek, Jiří (referee) ; Heidingsfeld, Olga (referee)
Yeasts are capable of forming a wide range of multicellular communities, which enable the survival in harmful and changing environment. Surface associated biofilms, often connected with infections in human body, and colonies can serve as an example of such populations. This work investigates formation and development of complex structured colonies of Saccharomyces cerevisiae, which can be considered as a distinctive feature of yeast strains isolated from the wild. Architecture and properties of such colonies are fundamentally different from the spatially undifferentiated colonies of most of laboratory strains and resemble in many ways rather natural biofilms of pathogenic yeasts. Yeast populations use specific developmental processes induced by communication mechanisms to synchronize the early stages of their development. Formation of specific three-dimensional colony architecture is enabled by the presence of extracellular matrix and adhesive protein Flo11p which provide stability and integrity of the whole structure. Protection of the colonies is accomplished by spatially differentiated cell subpopulations using various mechanisms such as expression of efflux pumps capable of removing toxic substances or production of extracellular matrix functioning also as selectively permeable barrier. Phenotypic...
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Differentiation in Saccharomyces cerevisiae colonies
Čáp, Michal ; Palková, Zdena (advisor) ; Pichová, Iva (referee) ; Demnerová, Kateřina (referee)
Yeast colonies are, alongside to bacterial biofilms, multicellular communities formed by unicellular microorganisms. These specific communities differ in many ways from populations cultivated in planktonic cultivations. Gradients of nutrients, metabolic by- products and other factors are formed and preserved within these structures, which provides a basis for cellular differentiation. Current literature concerning these issues with emphasis on yeast colonies and biofilms is summarised in the Introduction of this work. Section Results then describes my contribution to the knowledge on the differentiation of the colonies of Saccharomyces cerevisiae as a model system for studying microbial multicellular structures. Previously described horizontal differentiation, i.e. differentiation between colony centre and margin, is further characterised with respect to ammonia signalling and stress resistance. The importance of genes conferring the cell`s oxidative stress resistance in colony differentiation was studied and it was concluded that not stress resistance but rather metabolic and other changes promoted by ammonia signal are important for colony differentiation and survival. A new type of colony differentiation - the horizontal, i.e. differentiation between upper and lower part of the colony, is...
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