|
|
Analysis of embryotoxic effect of hydrocortisone using chick embryotoxicity screening test (CHEST).
Janíková, Michaela ; Peterka, Miroslav (advisor) ; Hovořáková, Mária (referee)
Cleft lip is one of the most common human birth deffects. Its etiopathogenesis is multifactorial and many aspects of its occurrence remain unknown in the fields of both genetics and teratology. One of the set of known negative external factors causing cleft lip is chemical hydrocortisone. Its effect on cell proliferation is highly heterogeneous and depends on attributes of a specific cell population. In this work we studied the cleft beak origin after the hydrocortisone treatment on the basis of Chick Embryotoxicity Screening Test (CHEST). Our main aim was to detect cell cycle changes in the chick frontonasal process after hydrocortisone injection via flow cytometry analysis. Hydrocortisone caused S phase arrest within a minor subpopulation of highly granular cells with specific cell cycle. This sensitive subpopulation was localized in the areas of previously defined proliferative centers within the frontonasal process using immunohistochemistry of frozen sections. Quantitative analysis of cells in these areas revealed significant decrease of M phase portion in the hydrocortisone treated samples in comparison with the control samples. The TUNEL staining of histological sections was used to determine the apoptotic rate in the frontonasal process. The comparison between the control and the...
|
|
|
Role of RecQ helicases in maintenance of genomic stability during mitosis
Černoch, Marek ; Janščák, Pavel (advisor) ; Půta, František (referee)
Helicases are proteins capable of unwinding nucleic acids, their malfunction can be dangerous for genome stability of the cell. Five RecQ-family helicases identified in human cells participate in many cellular events during the whole cell cycle, including mitosis, and therefore are very important for correct functioning. The mutations in RecQ helicases can cause them to malfunction and seriously damage various cell processes, for example DNA replication, DNA damage control or sister chromatids separation. The mutations can also lead to dangerous syndromes, with the hallmark symptom of increased risk of cancer.
|
|
|
Regulation of cell cycle in Bacillus subtilis.
Zelenka, Tomáš ; Lichá, Irena (advisor) ; Harant, Karel (referee)
2 Abstract Relations between several events running in bacterial cell during cell cycle were the subject of many studies during last years. More advanced techniques showed, that bacterial cell life has much more variable factors, than we supposed before. Relatively recent researches managed to reveal function and in few events molecular principle of several mechanisms coordinating those events such as progression of replication and its initiation, segregation of newly replicated chromosomes and after all synchronization of complex cell division machinery. Furthermore it showed variability of those events during changing living conditions of the cell. Keywords: Cell cycle, regulation, initiation, replication, segregation of chromosome, cytokinesis, Bacillus subtilis
|
|
| |
|
|
Role of PML in nucleolar functions
Kučerová, Alena ; Hodný, Zdeněk (advisor) ; Skalníková, Magdalena (referee)
Promyelocytic leukemia protein (PML) is a tumour suppressor which is frequently downregulated in human tumours. PML plays a role in many cellular processes including DNA damage response, senescence and apoptosis and is mainly localized in special structures called PML nuclear bodies (PML NBs). The nucleolus is a key nuclear compartment, where transcription of ribosomal DNA and biogenesis of ribosomes take place. The nucleolus is also called a stress sensor because of its role, for instance, in stabilization of tumour suppressor p53. Localization of PML to the nucleolar periphery appears to be prominent after disturbance of nucleolar functions - for example inhibition of rRNA transcription or processing. Thus the relationship between the nucleolus and PML nuclear bodies may be important for cellular response to stress. However, the role of PML nucleolar associations in nucleolar function including mechanism of formation of these structures remain unclear. Here we characterised PML nucleolar structures and mechanism of their formation. We showed that formation of PML nucleolar structures is not caused by replication stress, is not dependent on any specific phase of cell cycle and is not caused by DNA damage response but is induced by topological stress due to inhibition of toposiomerase function....
|
|
|
Emergent properties of the G1/S network
Dražková, Jana ; Tomášek, Petr (referee) ; Palumbo,, Pasquale (advisor)
Tato práce se zabývá buněčným cyklem kvasinky Saccgaromyces cerevisiae. Oblastí našeho zájmu je přechod mezi G1 a S fází, kde je naším cílem identifikovat velikosti buňky v době počátku DNA replikace. Nejprve se věnujeme nedávno publikovanému matematickému modelu, který popisuje mechanismy vedoucí k S fázi. Práce poskytuje detailní popis tohoto modelu, stejně jako časový průběh některých důležitých proteinů či jejich sloučenin. Dále se zabýváme pravděpodobnostním modelem aktivace replikačních počátků DNA. Nově uvažujeme vliv šíření DNA replikace mezi sousedícími počátky a analyzujeme jeho důsledky. Poskytujeme také senzitivní analýzu kritické velikosti buňky vzhledem ke konstantám popisujícím dynamiku reakcí v modelu G1/S přechodu.
|
|
|
Coherence-controlled holographic microscope in cell's life cycle research
Bartoníček, Jan ; Chmelík, Radim (referee) ; Uhlířová, Hana (advisor)
The subject of the bachelor thesis is live-cell imaging in a transmitted-light holographic microscope which was designed at the Institute of Physical Engineering BUT and comparing this imaging method with the phase-contrast microscopy. The first part is dedicated to a basic description of used imaging techniques and a cell biology. A description of an experiment preparation follows. In the part dedicated to a data analysis the method of dynamic phase differences is described and the method of growth monitoring is proposed. Both methods were used for the analysis of experiments which are described in the last part of this work. Experiments were focused on acquiring time-lapse data of a cell’s cycle and particularly the mitosis.
|
|
| |
|
| |
|
| |
guest ::
