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Analysis of CESA complexes dynamics in plant cytoskeletal mutants
Dubenecká, Kamila ; Schwarzerová, Kateřina (advisor) ; Malínská, Kateřina (referee)
The basis of this study are mutant plants with ARP2/3 complex lacking in one of its subunits (arpc5 and arp2). These plants also express CSC subunit CESA6 of primary cell wall tagged by YFP. Thanks to modern imaging technologies, it is possible to observe the movement of tagged cellulose synthase complexes in vivo at plasmatic membrane. Kymograph analyses was used to measure the velocity of CESA complexes. In addition to observing CESA complexes directly on the plasma membrane, experiments were made to regenerate cell walls of protoplasts of Arabidopsis thaliana plants arpc5 and WT. It was found, that observed mutants arpc5 and arp2 have reduced velocity of CESA complexes in comparison to WT and arpc5 protoplasts regenerate cellulose mesh of cell wall slower. Keywords: Cellulose synthesis, ARP2/3 complex, CESA, CSC velocity, arpc5, arp2, Arabidopsis thaliana.
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Study of adhesive penetration into the wood cell wall
Janová, Petra ; Krbila, Jaromír (referee) ; Vaněrek, Jan (advisor)
This labor is based on penetration of adhesive into a wood cell walls. It focuse on adhesives basicly used for construction purposes, especially on epoxy resins. The labor contains the use of methods for precise detection adhesive in wood and methodics for choice of adhesive and wood basically used for bonding. It describes the experimentally detected dependence of contact angle on viscosity epoxy resins.
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Method´s analysis of submicroscopy structure of wood cell wall determination
Martinek, Radomír ; Kuklík,, Pavel (referee) ; Vaněrek, Jan (advisor)
The content of this study is focused on the influence of the structure of wood at microscopic and submicroscopic level on its mechanical properties. The wood cell wall consists of several layers, the dominant layer being layer S2, which occupies up to 80 % of the total thickness of the wood cell wall. Unique feature of this layer is that cellulose microfibrils placed in this layer are highly aligned and spirally wound around the cell axis. The inclination of these microfibrils is called microfibril angle (MFA) and is the key feature that affects mechanical properties of wood and its shrinkage. In theoretical part of this thesis methods for measuring microfibril angle are described. A method for measuring mechanical properties of the wood cell wall called nanoindentation is discussed in detail. In the practical part of this thesis, microfibril angle is measured by means of polarized light microscopy and mechanical properties of wood cell wall is determined by means of nanoindentation.
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Functions of the exocyst complex in secretion and cell wall biogenesis
Vukašinović, Nemanja ; Synek, Lukáš (advisor) ; Růžička, Kamil (referee) ; Kost, Benedikt (referee)
The mechanical strength of plant tissues and organs can be attributed to specific properties of the cell wall. In many cases, in order to establish their final shape, cells deposit various cell wall materials in a localized manner. This is achieved by highly organized action of the endomembrane system which is essential for biosynthesis and secretion of cell wall proteins and polysaccharides. The exocyst complex is a conserved tethering complex in eukaryotes and it is involved in tethering of secretory vesicles to the sites of secretion at the plasma membrane. In this study, we address several aspects of the plant exocyst complex architecture and cell wall development using molecular biology techniques and advanced confocal microscopy. We demonstrated that two SEC10 exocyst subunits are present in Arabidopsis thaliana and share redundant functions. We also showed that the architecture of the plant exocyst complex shares several structural features with the yeast one. We demonstrated the importance of the functional EXO84b exocyst subunit for normal tracheary element development and showed that the main constituents of the secondary cell walls are deposited normally in exocyst mutants. We described a clear difference in the exocyst microtubule-independent dynamics in epidermal cells vs. cell type...
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The effect of desiccation on streptophyte algae - mechanisms of stress resistance
Pošmourný, Martin ; Pichrtová, Martina (advisor) ; Vosolsobě, Stanislav (referee)
In this thesis I dealt streptophyta algae resistance against desiccation. Even though the area previously devoted only a few people. Considerable amount of work in recent years has been published on the subject. They were found interesting information and discovered new facts. Research continues on and on, and it would be useful to look at what was observed. I believe that understanding this phenomenon is the key to understanding some of the events in the evolution of nature and realizing how tough life can be on the very border of its possible occurrence. I tried to sort out the current knowledge about the mechanisms of stress resistance streptophyta algae and hope that I obtained an overview will help me understand better this issues. So far, it has been observed several approaches to defend against drying. Preventing drying, adaptation to water shortage and tolerance to desiccation. Among the preventive methods of defense include creating clusters of cells, multi-layered mats or secretion mucilage. As an adaptation to the lack of water algae evolved more complex answers in the form of changes in ultrastructure, or regulation of physiological processes. Klebsormidium is capable of half an hour to start the production of significant quantities callose and incorporate it into the cell wall. This...
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Isolation of plant organelles and study of transport mechanisms
Kettnerová, Dana ; Martin, Jan (advisor) ; Tůmová, Lenka (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmacognosy Diploma thesis Author: Dana Kettnerová Supervisor: PharmDr. Jan Martin, Ph.D. Title of diploma thesis: Isolation of plant organelles and study of transport mechanisms Key words: isolation, chloroplast, protoplast, vacuole, cell wall Isolation of plant organelles and other cellular components is essential for the study of physiological and pathological processes within the plant cell. It is possible to analyze cell structures, detect accumulation of certain metabolites, ions, enzymes and other substances thanks to the isolation. The goal of this diploma thesis was to provide an overview of isolation methods used for the isolation of cell wall, protoplasts, chloroplasts and vacuoles of plant cells. Isolation processes used for individual types of cell structures, the pros and cons of the various isolation methods, components of used media and their functions, as well as the structure and function of individual plant structures were described.
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Visualization of cell structures in leaf cells of Malus domestica as a tool for study of Malus-Venturia inaequalis interactions
Zajícová, Iveta ; Schwarzerová, Kateřina (advisor) ; Mašková, Petra (referee)
Apple scab, the most serious disease of apple is caused by fungal pathogen Venturia inaequalis. Knowledge about the apple response to apple scab attack on the cellular and tissue level is insufficient. For studies of Malus-Venturia interaction on the cellular and tissue level, the establishment of methods for cell structures visualization in apple leaves is necessary. In this work, the experimental plant material grown in vitro and ex vitro was successfully established and the method of apple infection by conidia of V. inaequalis was optimized. Various methods of cell components visualization such as vital staining, in situ immunolocalization, transformation, environmental scanning electron microscopy and confocal microscopy, were tested. Cell structures, such as the cytoskeleton, the cell wall and the cuticle were visualized in apple leaves. Preliminary experiments following specific the changes of cell wall structures induced by V. inaequalis attack were performed. Further, changes of cuticle structure, the first barrier for penetration of pathogen to plant tissues during infection, were observed during the leaf ontogenesis. Powered by TCPDF (www.tcpdf.org)
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Specificity of selected exocyst subunits in trichome development
Glanc, Matouš ; Žárský, Viktor (advisor) ; Binarová, Pavla (referee)
Trichomes are fine epidermal outgrowths covering aerial organs of most land plants. Although unicellular trichomes of Arabidopsis thaliana have long been used as a model system in plant cell and developmental biology, surprisingly little is known about the processes involved in cell wall biogenesis during the last stage of trichome maturation. A role of EXO70H4, a putative subunit of the vesicle tethering complex exocyst, in trichome maturation has recently been identified in our laboratory. Image analysis, histochemical detection and FT-IR spectroscopy methods were used in this study to analyze cell wall defects of the exo70H4 LOF mutant, revealing the mutation causes altered deposition of pectins and possibly also lignins and hemicelluloses. Transgenic lines with EXO70 paralogues driven by the EXO70H4 promoter were prepared and their analysis revealed that the closest paralogue EXO70H3, unlike EXO70A1 and EXO70B1, can complement the exo70H4 mutation. Based on the results, questions concerning trichome cell wall composition, the role of EXO70H4 in trichome maturation and functions of the plant exocyst complex are discussed. Keywords: Arabidopsis, trichome, cell wall, secretory pathway, exocyst complex, EXO70H4, FT-IR spectroscopy
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Candida parapsilosis secreted aspartic proteinases: processing and secretion
Vinterová, Zuzana ; Heidingsfeld, Olga (advisor) ; Hodek, Petr (referee) ; Szotáková, Barbora (referee)
Candida parapsilosis is an emerging human opportunistic pathogen causing a wide spectrum of potentially life-threatening infections in immunocompromised hosts. One of the most important virulence factors of Candida spp. is a production of secreted aspartic proteinases (Saps). Presented thesis is mainly focused on the study of secreted aspartic proteinase 1 (Sapp1p) of C. parapsilosis, its processing and secretion under variable conditions and by use of various experimental models. Sapp1p is secreted by C. parapsilosis cells into the extracellular space as a completely processed and fully active enzyme. Experiments studying the C. parapsilosis cell wall (CW) confirmed the prolonged presence of completely processed Sapp1p on the cell surface (CW- Sapp1p). Proteolytic activity assay performed with the intact cells showed that CW-Sapp1p is proteolytically active prior to its release into the extracellular space and is capable of substrate cleavage. Biotinylation experiments with consecutive MS analysis revealed that CW-Sapp1p biotinylation is incomplete but saturable process, leaving partially unlabelled molecules. The accessibility of individual lysine residues in the Sapp1p molecule varied, with exception of four residues that were labelled in all of our experiments performed. The final step of...
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