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Nucleolus and Its Associated Chromatin
Cvačková, Zuzana ; Raška, Ivan (advisor) ; Smetana, Karel (referee) ; Nedvídek, Josef (referee)
Mammalian chromosomes occupy chromosome territories within nuclear space the positions of which are generally accepted as non-random. However, it is still controversial whether position of chromosome territories is maintained, together with their neighborhood, in daughter cells. We addressed this issue and investigated maintenance of various chromatin regions of unknown composition as well as nucleolus-associated chromatin, a significant part of which is composed of ribosomal genes-bearing chromosomes. The photoconvertible histone H4-Dendra2 was used to label such regions in transfected HepG2 cells, and its position was followed up to next interphase. The distribution of labeled chromatin in daughter cells exhibited a non- random character. However, its distribution in a vast majority of daughter cells extensively differed from the original ones and the labeled nucleolus-associated chromatin differently located into the vicinity of different nucleoli. Therefore, our results were not consistent with a concept of preservation chromatin position. This conclusion was supported by the finding that the numbers of nucleoli significantly differed between the two daughter cells. Our results support a view that while the transfected daughter HepG2 cells maintain some features of the parental cell chromosome...
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Glycophenotype of head and neck carcinomas
Chovanec, Martin ; Smetana, Karel (advisor) ; Mandys, Václav (referee) ; Martínek, Jindřich (referee)
1 THESIS The thesis deals with the glycophenotype analysis of normal squamous cell epithelia, and head and neck squamous cell carcinomas. Many research projects focus on improving patients prognosis studying biological properties of the tumor. The alterations of carbohydrate motives occur during cell differentiation and carcinogenesis. Lectins are proteins that bind to specific carbohydrate structures. Animal lectins, including human lectins, consist of five subfamilies according to their binding specifity. Much attention is paid to the investigation of galectins - -galactoside binding proteins. Their carbohydrate recognitive function is not dependent on the presence of Ca2+ ions, contrary to the other lectin types. Galectins play important roles in many biological processes, e.g. in adhesion, intercellular interactions, immunomodulation, inflammation, cell growth, apoptosis, pre-mRNA splicing. Alterations in any of these might contribute to the malignant transformation and cancer progression. Endogenous lectins (galectins, Langerin, Manose receptor) were detected using immunohistochemistry, galectin-binding sites were localized by lectin histochemistry. Reverse lectin histochemistry was employed for the study of glycosaminoglycan binding sites. Human (squamous cell epithelia of the oral cavity, oropharynx...
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