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Non-economic neocolonialism and its conflicts
Dvořák, Michal ; Riegl, Martin (advisor) ; Soukup, Jaromír (referee)
The aim of the thesis is to analyze specific phenomenon of non-economic neocolonialism and its conflicts. I have done the analysis of two conflicts (in Western Sahara and in Namibia) in context of the Cold War, I was trying to discover the context between dynamics and domestic political development of metropolitan country and the conflict. The next aspect was a regional dimension of the conflicts, that is why I analyzed the influence of neighboring countries and their motivation in the conflicts. The main aspect was an international dimension of the conflicts, that is why I examined the approach of the Soviet Union, the United States of America, the United Nations and the Organization of African Unity to the conflicts. The main research question was: What types of processes and mechanisms have led Namibia to independence, while the Western Sahara was still under foreign control? The next questions were: What led the superpowers to affect the conflicts, which were in the periphery of world competition? How behaved the world organizations during the conflicts? Had any influence in these conflicts? And last: What kind of interest had the neighboring countries in these conflicts?
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Molecular mechanisms of amoeboid invasion of cancer cells
Paňková, Daniela ; Brábek, Jan (advisor) ; Dvořák, Michal (referee) ; Vomastek, Tomáš (referee)
Tumour cell invasion is one of the most critical steps in malignant progression. It includes a broad spectrum of mechanisms, including both individual and collective cell migration, which enables them to spread towards adjacent tissue, and form new metastases. Understanding the mechanisms of cell spreading, and invasion, is crucial for effective anticancer therapy. Two modes of individual migration of tumour cells have been established in a three-dimensional environment. Mesenchymally migrating cells use proteases to cleave collagen bundles, and thus overcome the ECM barriers. Recently described protease-independent amoeboid mode of invasion has been discovered in studies of cancer cells with protease inhibitors. During my PhD study, I have focused on determining the molecular mechanisms involved in amoeboid invasion of tumour cells. We have examined invasive abilities in non-metastatic K2 and highly metastatic A3 rat sarcoma cell lines. We have shown that even though highly metastatic A3 rat sarcoma cells are of mesenchymal origin, they have upregulated Rho/ROCK signalling pathway. Moreover, A3 cells generate actomyosin-based mechanical forces at their leading edges to physically squeeze through the collagen fibrils by adopting an amoeboid phenotype. Amoeboid invasiveness is also less dependent on...
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The VoIP protocols real time analyzer
Dvořák, Michal ; Jirovský, Václav (advisor) ; Kvítek, Petr (referee)
This thesis goal is to desing an application which would allow real-time monitoring and analyzing of services for transferring voice over the Internet network, based on the study of the relevant standards. The thesis focuses on monitoring the H.323 standard. An implementation is a part of this thesis.
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The biological importance of CAS SH3 domain tyrosine phosphorylation
Janoštiak, Radoslav ; Brábek, Jan (advisor) ; Dvořák, Michal (referee)
Protein CAS is a major tyrosine-phosphorylated protein in cells transformed by v-crk and v-src oncogenes. It is a multidomain adaptor protein, which serves as a scaffold for assembly of signalling complexes which are important for migration and invasiveness of Src-transformed cells. A novel phosphorylation site in N-terminal SH3 domain was identified - tyrosine 12 located on binding surface of CAS SH3 domain. To study biological importance of tyrosine 12 phosphorylation, non-phosphorylable (Y12F) and phosphomimicking ( Y12E) mutant of CAS were prepared. We found that phosphomimicking mutation Y12E leads to decreased interaction of CAS SH domain with kinase FAK a phosphatase PTP-PEST and also reduce tyrosine phosphorylation of FAK. Using GFP-tagged CAS protein, we show that Y12E mutation caused delocalization of CAS from focal adhesion but has no effect on localization of CAS to podosome-type adhesion. Non-phosphorylable mutation Y12F cause hyperphosphorylation of CAS substrate domain and decrease turnover of focal adhesion and associated cell migration of mouse embryonal fibroblasts (MEFs) independent to integrin singalling. Analogically to migration, CAS Y12F decrease invasiveness of Src-transformed MEF. The results of this diploma thesis show that phosphorylation of Tyr12 in CAS SH3 domain is...
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Regulation of transcription by proteins of the Early growth response and Myb families
Čermák, Vladimír ; Dvořák, Michal (advisor) ; Vomastek, Tomáš (referee) ; Elleder, Daniel (referee)
The regulation of transcription of tens of thousands of genes in a vertebrate organism is an enormously complex phenomenon which entails the participation of thousands of various regulatory proteins. The largest functional category of these regulators is accounted for by sequence-specific DNA-binding proteins known as transcription factors. Proteins of the EGR and Myb families of transcription factors are long-studied regulators of a variety of physiological processes including cellular proliferation and differentiation. The structural and physical aspects of their function have been well characterized. Their cell-type specific participation in complex gene-regulatory networks, on the other hand, is still incompletely understood and represents a major challenge in the respective research areas. Preliminary analysis of gene expression data from metastasizing PR9692 and non- metastasizing PR9692-E9 chicken sarcoma cell lines revealed that the transcription factor EGR1 is expressed at a higher level in metastasizing cells and can thus take part in the regulatory processes that underlie the differences between the two cell lines. Further investigation demonstrated that the introduction of exogenous EGR1 into PR9692-E9 cells restored their metastatic potential to a level indistinguishable from PR9692...
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The use of CAM assay for characterization and study of cancer cell invasive properties
Vágnerová, Lenka ; Dvořák, Michal (advisor) ; Geryk, Josef (referee)
The chorioallantoic membrane (CAM) of chicken embryos belongs to the in vivo model systems frequently used for the study of angiogenesis and cell invasiveness. Using CAM assay we have tested selected chicken sarcoma cell lines characterized by different angiogenic properties and different ability to form metastasis. In addition to CAM assay, several other methods have been used to characterize the phenotype of these cell lines. We have selected a few proteins which could significantly influence the angiogenic and metastatic properties of investigated cell lines. We have established cell lines stably overexpressing these genes and compared their phenotypes with parental cell lines. We have shown that genes encoding ISL1, ARNT2, PROM1, HOXA11 proteins participate, in our experimental model, in activation of programes controlling angiogenesis and cell invasion.
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Gene expression in chicken embryo: micromanipulation and visualization methods
Bendová, Michaela ; Dvořák, Michal (advisor) ; Hirsch, Ivan (referee) ; Krylov, Vladimír (referee)
The aim of this work was to obtain better insight into the principles of cell structures and organs in the chicken embryo development. To reach this goal special methods of micromanipulations and visualization in vitro, ex vivo, ex ovo and in ovo were implemented and adjusted. These methods were used to study gene expression in neural crest development and eye development. In the course of long term research in our laboratory we observed that oncoprotein v-Myb influences the development of the neural crest and has the capacity to change natural cell fate. We performed a series of experiments to investigate v-Myb protein influence on neural crest cells differentiation, especially melanocyte lineage development, and its influence on gene expression in the neural crest. Therefore we focused on Gremlin 2 (PRDC), the gene upregulated by v-Myb in the neural crest. The established procedure of electroporation in ovo was adjusted to transfect cells of the developing eye and used to study gene expression during lens induction. The results obtained from chicken embryo experiments endorsed the study performed on mouse embryos. Futhermore, the electroporation technique was slightly modified for manipulations of the neural retina in the developing eye in ovo. Thereafter, the retinas were processed ex vivo and...
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Cytokine expression in chemically-induced senescence
Nováková, Zora ; Hodný, Zdeněk (advisor) ; Hampl, Aleš (referee) ; Dvořák, Michal (referee)
AbstractJanderova-Rossmeislova L., Novakova Z., Vlasakova J., Philimonenko V., Hozak P., Hodny Z., 2007. PML protein association with specific nucleolar structures differs in normal, tumor and senescent human cells. J. Struct. Biol. 159, 56-70. Cellular senescence, widely recognized as a potent suppressor of tumorigenesis, represents response to cellular stress and DNA damage which results in irreversible cell growth arrest. Growing evidence signalizes crucial role of cytokine production in senescence phenomenon. Recently, many research groups have efforted to define exact character of senescence-associated secretory phenotype and its function in senescence development and maintentance. Factors secreted by senescent cells, mainly of proiflammatory character, were found to have pronounced effects on their environment as well as on its own producer. These observations were obtained preferentially on models of replicative senescence and oncogene-induced senescence. Vlasakova J, Novakova Z, Rossmeislova L, Kahle M, Hozak P, Hodny Z. 2007. Histone deacetylase inhibitors suppress IFNalpha-induced up-regulation of promyelocytic leukemia protein. Blood 109: 1373-80 Novakova Z, Man P, Novak P, Hozak P, Hodny Z. 2006. Separation of nuclear protein complexes by blue native polyacrylamide gel electrophoresis....
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Study of extracellular nucleic acids in maternal circulation in the cases of pathological and physiological pregnancies
Žejšková, Lenka ; Hromadníková, Ilona (advisor) ; Černá, Marie (referee) ; Dvořák, Michal (referee)
In 1997, Prof. Dennis Lo discovered the presence of cell-free fetal DNA (cffDNA) in the maternal plasma and serum of pregnant women. This finding started the development of new non-invasive prenatal diagnosis methods, which are currently in the forefront of the advanced care of mother and fetus. Non-invasive genetic tests based on the detection of paternally inherited alleles, including determination of fetal sex in cases at risk of X-linked disorders or congenital adrenal hyperplasia and RHD or RHCE genotyping in alloimunized pregnancies, were quickly introduced into routine practice. This thesis focuses on the basic characteristics of cffDNA and fetal cells in maternal circulation and its usage for non-invasive prenatal diagnosis, especially in cases of placental insufficiency related complications, e.g. preeclampsia and IUGR. This severe disorder is characterized by placental dysfunction with an abnormal invasion of trophoblasts and a defect in the transformation of maternal spiral arteries, leading to placental ischemia followed by increased apoptosis of trophoblast associated with an elevated concentration of cell-free nucleic acids in maternal circulation. Until recently, cffDNA quantification studies were mostly done using amplification of SRY or DYS-14 genes localized on chromosome Y, and...
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