|
|
Analysis of neurite directionality
Plišková, Diana ; Čmiel, Vratislav (referee) ; Odstrčilík, Jan (advisor)
Práca je zameraná na navrhnutie vhodnej metódy analýzy smerovosti neuritov. Využité boli snímky neurónov z fluorescenčnej mikroskopie. Pred samotnou segmentáciou bolo potrebné snímky predspracovať, pričom sa postupne využila úprava kontrastu, ostrenie a adaptívna filtrácia pomocou Weinerovského filtru. Jednotlivé návrhy metód segmentácie pozostávali z prostého prahovania, narastaním oblastí a využitím morfologických operácií. Následná analýza smerovosti využívala smer gradientov v obraze. Navrhnutá metóda bola využitá aj ako klasifikátor, ktorý dokázal rozdeliť jednotlivé snímky do skupín podľa smeru rastu.
|
|
|
Quantitative fluorescence microscopy techniques to study three-dimensional organisation of T-cell signalling molecules.
Chum, Tomáš ; Cebecauer, Marek (advisor) ; Lánský, Zdeněk (referee) ; Brameshuber, Mario (referee)
10 SUMMARY Proteins represent one of the basic building blocks of all organisms. To understand their function at the molecular level is one the critical goals of current biological, biochemical and biophysical research. It is important to characterise all aspects that affect the localisation of proteins into different compartments with specific functions, the dynamic structure of proteins and their role in multiprotein assemblies, because altering these properties can lead to various diseases. Most of the proteomic studies are nowadays performed using biochemical approaches that allow us to study multicellular organism or tissue at once. The disadvantage of these methods is complex preparation of sample and the need for a large number of cells, which leads to the loss of information at the molecular level and in individual cells. On the contrary, microscopy can provide rather detailed information about proteins of interest and at the level of a single cell. A variety of fluorescence microscopy methods in combination with recombinant DNA techniques were applied to elucidate subcellular localisation of transmembrane adaptor proteins (TRAPs) in human lymphocytes and their nanoscopic organisation at the plasma membrane. Linker of activation of T lymphocytes (LAT), phosphoprotein associated with...
|
|
|
Aflatoxins in food and their influence on DNA and cell lines
Šislerová, Lucie ; Pernicová, Iva (referee) ; Brázda, Václav (advisor)
Aflatoxins present a great danger due to their high toxicity and carcinogenicity, which is not easily avoided in everyday life. Intoxication with aflatoxins causes a wide range of diseases ranging from mild diseases to organs necrosis or death. Aflatoxins mostly affect the liver, where it degrades and the formation of subsequent metabolites, which are the most toxic to the body. For this reason, their precise determination and understanding of the principle of their effect is very important. In this work, methods for monitoring and closer determination of aflatoxin effects on human cells were calibrated. The methods that were used are: MTT viability assays, fluorescence microscopy and flow cytometry. Next, the amount of aflatoxins present in different foods with different storage conditions was measured. For this analysis were used ELISA assays RIDASCREEN Aflatoxin Total and RIDA Aflatoxin column. Calibrated methods were compared with the methods already used to determine the effect of aflatoxins and the results of the ELISA tests were compared with the limits of aflatoxin levels permitted by the Czech legislation. None of the controlled foods contained above-the-limit concentration of aflatoxins, which in the Czech Republic is set at 4-10 µg/l (varies for different types of food). Foods that were poorly stored but not visibly affected by fungi showed the highest levels of aflatoxins. The LD50 value for aflatoxin B1 was determined to 12,25 µM. The type of cell death caused by aflatoxins was determined by flow cytometry and these data were further confirmed by fluorescence microscopy images.
|
|
|
Characterization of PHA producing microbial cells by advanced microscopic and cytometric techniques
Dlouhá, Karolína ; Nováčková, Ivana (referee) ; Obruča, Stanislav (advisor)
The aim of this bachelor thesis is to document production of polyhydroxyalkanoates in selected bacterial strains, which were Pseudomonas thermotolerans, Chelatococcus daeguensis, Tepidiphilus thermophilus and Chelatococcus thermostellatus. In the case of the microorganisms Tepidiphilus thermophilus and Pseudomonas thermotolerans, the production of PHA´s has not yet been described, and in the Chelatococcus bacteria, which were analysed in this work, the production has not yet been documented by electron microscopy. In this work, the selected producers were analysed by flow cytometry first, using BODIPY and Nile Red as fluorescence probes. Selected producers, for which was production confirmed, were analysed by other methods, such as fluorescence microscopy, cryo scanning electron microscopy and transmission electron microscopy. In the bacterial culture of Pseudomonas thermotolerans, PHA´s production wasn´t confirmed by the first analysis by flow cytometer. For other microorganisms was production confirmed. Chelatococcus bacteria clearly proved to be better producers. Bacterial cells of Tepidiphilus thermophilus produced smaller granules and in lower amount.
|
|
|
Human 4E protein family in stress granules granules and their further characterization
Hrbková, Pavlína ; Frydrýšková, Klára (advisor) ; Hašek, Jiří (referee)
Eukaryotic initiation factor 4E (eIF4E) is a key part of initiation and regulation of translation in human cells. Three members of human eIF4E proteins have been characterized: eIF4E1, eIF4E2 and eIF4E3. Cellular stress causes translation initiation inhibition followed by disassembly of the polysomes, those processes are accompanied by the assembly of cytoplasmic RNA granules, called stress granules (SG). Stress granules are dynamic structures whose composition may vary depending on the cell type and the stress stimulus. In this study, human cells were subjected to the following stress conditions: high temperature (HS), sodium arsenite (AS) or hypoxia. Using fluorescence microscopy, pairs of human translational initiation factors from the 4E protein family were visualized and their localization to SG was assessed with one GFP- 4E incorporated in the stable cell line and the other one detected endogenously. Here we show eIF4E1 being a part of all the SGs, both in HS and AS conditions. Next, the eIF4E1 and eIF4E3 proteins together form more SGs than proteins eIF4E1, respectively eIF4E3, with eIF4E2. And last, that the presence of the particular 4E protein has no effect on the composition of SGs. Furthermore, selected groups of proteins were assessed for their potential to localize to the SGs under HS...
|
|
|
Bigels - Preparation and Characterization
Mušková, Alexandra ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with study of bigels, which are composed of hydrogel and oleogel. The aim of this work is to prepare and characterize bigels. Preparation of hydrogels was based on interaction between hyaluronan and cationic surfactant carbethopendecinium bromide. Oleogels were prepared by mixing a non-ionic surfactant (sorbitan monopalmitate) with sunflower oil. Individual bigels were prepared by mixing the various rations of hydrogel and oleogel, and were characterized using a fluorescence microscope and rheological measurements. Fluorescence observations were done on prepared samples using Nile Red, Perylene, HPTS, ATTO 655 and fluorescein. Rheological experiments show that pure oleogel is the strongest and most solid in comparison with bigels and hydrogels. The greater amount of oleogel in system is, the stronger bigel is.
|
|
|
Intrinsic fluorescence of bacteria Cupriavidus necator
Marková, Kateřina ; Obruča, Stanislav (referee) ; Mravec, Filip (advisor)
This thesis focuses on autofluorescence of flavins in gram-negative bacteria Cupriavidus necator H16 and its mutant strain PHB-4. The main methods used were fluorescence microscopy and flow cytometry. To confirm the presence of flavins, excitation and emission spectra of the bacterial suspension were measured, which were compared with flavin standards. In the part of testing cells without stress response, the autofluorescence of bacteria in PBS buffer and cell suspensions stained with fluorescence probe BODIPY 493/503 was measured. The ratio of short fluorescence lifetime to long autofluorescence lifetime, and its dependence on fluorescence probe was compared with previous conditions. Autofluorescence of the supernatant was measured; it was found that the relative amplitude of long lifetime was multiple times higher than in the cell. In the part devoted to the stress response, this thesis was focused on the amount of dissolved oxygen in the production medium and the effect on bacterial autofluorescence. Then differently concentrated hydrogen peroxide was used, the best results were obtained from the concentration of 100 mM in media. For comparison a combination of hydrogen peroxide with ferro-ammonium sulphate was used, but there was no big difference. Sodium azide and antimycin A were selected as substances that directly influence on bacterial respiratory chain. Both compounds affected change in the ratio of the relative amplitudes, but the distribution of these lifetimes and the autofluorescence change over time was affected only by sodium azide.
|
|
|
Formation of splicing machinery in the context of the cell nucleus
Stejskalová, Eva ; Staněk, David (advisor) ; Vanáčová, Štěpánka (referee) ; Malínský, Jan (referee)
Most of the protein coding genes of higher eukaryotes contain introns which have to be removed from primary transcripts to make mRNA which can be used as a template for protein synthesis. This crucial step in the pre-mRNA processing is carried out by the spliceosome, a complex ribonucleoprotein machine formed from small ribonucleoprotein particles (snRNPs). snRNPs biogenesis is a complex process composed of several steps which take place in both the cytoplasm and the nucleus. Spliceosome assembly is highly dynamic and tightly regulated and pre-mRNA splicing depends not only on the sequence of the pre-mRNA itself but also on the nuclear context, such as the chromatin modifications. How do cells regulate where and when the spliceosome would be assembled? What determines which introns will be spliced? These are fundamental, yet unanswered, biological questions. In this work we analyzed the formation of splicing machinery in the context of the cell nucleus from several different points of view. First, we investigated the unexpected connection between splicing factor U1-70K and the survival of motor neurons (SMN) complex which is a major player in the snRNP biogenesis pathway. We revealed that U1-70K interacts with the SMN complex and that this interaction is crucial for the stability of nuclear gems, small...
|
|
|
The effect of vanZTei and vanZg expression on resistance to glycopeptide antibiotics in Staphylococcus aureus
Zieglerová, Leona ; Balíková Novotná, Gabriela (advisor) ; Lichá, Irena (referee)
A membrane protein VanZTei which is encoded by the gene vanZ from the vanA glycopeptide resistance gene cluster is a part of the large family of VanZ proteins. VanZTei confers resistance to teicoplanin in Enterococcus faecalis without the presence of other proteins encoded by the cluster. The aim of my work was to compare the ability of two orthologous proteins VanZTei and VanZg (from the genome of Enterococcus faecium) to confer resistance to glycopeptides in Staphylococcus aureus RN4220 and Enterococcus faecium. We have shown that VanZg increases resistance to teicoplanin (Tei) 8 to 16 times the and also to dalbavancin (Dalb) 8 times. VanZTei also confers resistance to Tei and Dalb, but the increase is only twofold. Conversely VanZTei confers resistance to newly synthetized glycopeptides more effectively than VanZg (fourfold increase of resistance confered by VanZTei and two to fourfold increase of resistance confered by VanZg). It suggests that both proteins have different specificity to antibiotics. In despite the mutants of S. aureus RN4220 VanZTei pRMC2 with increased resistance to teicoplanin (MICTei> 8 µg/ml) in which the resistance is dependent on vanZTei expression were selected. These resistant mutants do not carry mutation in a gene vanZTei or in its ribosomal binding site. Neither of the...
|
|
|
Cell layer cultivation in the microfluidic system
Kachan, Ksenia ; Svoboda, Ondřej (referee) ; Chmelíková, Larisa (advisor)
The theoretical part of this thesis describes the principles of cell culture in vitro and modern in vitro models for endothelial cell layer cultivation. It also describes the principles of confocal and fluorescence microscopy. The practical part is dedicated to working with cell cultures and realization of experiment with cell cultivation in microfluidic system. Cell layer was photographed using laser confocal scanning microscope Leica TCS SP8 X during the entire experiment. For processing and analysis of the obtained images, an algorithm in the software MATLAB was proposed.
|
guest ::
