National Repository of Grey Literature 28 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Analysis of functional interactions of phospholipids in the cell nucleus.
Biddle, Veronika ; Hozák, Pavel (advisor) ; Kaňka, Jiří (referee) ; Malínský, Jan (referee)
(English) Phosphoinositides (PIs) are glycerophospholipids with a negative charge. As components of cell membranes, PIs are involved in membrane and cytoskeletal dynamics, cell movement and signalling, and the modulation of ion channels and transporters. Apart from the cytoplasm, phosphoinositides also localise to the cell nucleus. PIs play a role in crucial nuclear processes, such as DNA transcription, pre-rRNA and pre-mRNA processing, cell differentiation, DNA damage response, or apoptosis. Phosphatidylinositol 4-phosphate (PI(4)P) and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) are the most abundant phosphoinositides in the cell. However, their exact localisation and function in the nucleus are largely unknown. Here, we describe their localisation at super-resolution level and their involvement in some nuclear processes. PI(4)P is present in nuclear lamina, nuclear speckles and nucleoli, and it forms small foci in nucleoplasm. The majority of nuclear PI(4)P localises to the nucleoplasm, whereas almost 16 % is present in nuclear speckles. On the other hand, the majority of nuclear PI(4,5)P2 localises to nuclear speckles, almost 30 % localises to nucleoplasm and the lesser portion to nucleoli. In the nucleoplasm, PI(4,5)P2 forms small foci called nuclear lipid islets (NLIs). Their core is...
Involvement of protein vinculin in mammalian gametogenesis
Darášová, Alžběta ; Hozák, Pavel (advisor) ; Kaňka, Jiří (referee)
One of the basic characteristics of living systems is a sexual reproduction, when the germ cells, sperm and egg, fuse. The key process in the germ cells development is meiosis. During meiotic division, several dramatic changes happen in the nucleus and different errors might appear, which may then result in various chromosomal aberrations and nondisjunctions leading to genetic diseases and infertility. The causes of infertility are very diverse, but many of them obviously come from the meiotic errors. One of the most critical parts for the successful meiotic progress is a prophase I, where the homologous chromosomes are paired by the protein structure of the synaptonemal complex (SC) and subsequent genetic recombinations by crossing- over accurate. Vinculin (VCL) is a cytoplasmic actin binding protein in the focal adhesions and adherent junctions and VCL acts as their essential regulator. Recently, this protein was also found in the nucleus of germ cells of certain organisms. However, the nuclear functions of vinculin have not been described yet. This diploma thesis focuses on the study of chromosomal dynamics in the gametogenesis of our mouse model, regarding the involvement of the nuclear vinculin in these processes. Our aim was to localize VCL in the nucleus of embryonic prophase oocytes using...
Regulation of development of mouse parthenogenetic embryos
Jettmarová, Dominika ; Fulka, Josef (advisor) ; Kaňka, Jiří (referee)
The development of mouse (Mus musculus) haploid parthenogenetic embryos does not reach the same level as normal embryos. The aim of this diploma thesis was to find out whether haploid parthenogenetic embryos of mice differ in the nucleocytoplasmic ratio. The volume of the nucleus increases with ploidity. The nucleocytoplasmic ratios of haploid embryos do not significantly change between the two-cell and four-cell stage (p = 0.052), there is a significant difference (p < 0.001) for diploid and tetraploid embryos. Non-standard nucleocytoplasmic ratio could be related to the problematic development. Understanding the regulation of preimplantational development of parthenogenetic embryos will increase the efficiency of haploid embryonic stem cell derivation.
Effect of selected endocrine disruptors on the male mouse reproductive system in vivo
Žatecká, Eva ; Pěknicová, Jana (advisor) ; Kubelka, Michal (referee) ; Kaňka, Jiří (referee)
In our environment there are many compounds which can negatively influence humans and wildlife. Every day, a vast number of environmental pollutants are released into our environment and there is no way to avoid their exposure. Some of these compounds can even mimic endogenous hormones and interfere with our endocrine system (so called endocrine disruptors), which is the key regulatory system controlling almost all physiological processes in human and animal bodies. Also the reproductive system is largely regulated by various hormones, and their proper function is crucial for gamete formation, fertilization and embryo development. Environmental pollutants are therefore considered as one of the possible causes of increased infertility in human population. This prompted us to study the effect of two endocrine disruptors (tetrabromobisphenol A - TBBPA, and zearalenone - ZEA) on the male mouse reproductive system in vivo. According to our results, TBBPA is able to induce apoptosis as well as changes in the expression of selected testicular genes and sperm protamination. Our results also suggest that permanent exposure to TBBPA slightly enhances its effect in the next generation, depending on whether the parents have been affected or not. We hypothesized that differential protamination of the sperm DNA...
The effect of diabetes mellitus on reproductive parameters and expression of selected testicular genes in diabetic mice
Valášková, Eliška ; Pěknicová, Jana (advisor) ; Kaňka, Jiří (referee)
According to the World Health Organization (WHO), 15% of couples in reproductive age suffer from infertility problems, and up to 60% of cases are caused by male factor. Causes of this condition could be genetic background, environmental factors and various diseases, including diabetes mellitus (DM). The aim of this study was to investigate the effects of DM on reproductive parameters and expression of selected testicular genes using mouse model (FVB inbred mouse strain). DM (type 1) was artificially induced by chemical substance streptozotocin, which causes destruction of pancreatic β cells. These mice were exposed to diabetic condition for 6 weeks and then subjected to analysis. Our results have shown that diabetic condition had an impact on body weight, weight of reproductive organs as well as kidneys and livers. We also observed decreased concentration and viability of diabetic sperm compared to control. Moreover, we noticed increased staining with apoptotic marker annexin V. Further, we evaluated changes of sperm nuclear proteins - protamines. In diabetic animals, we observed higher number of sperm with insufficient protamination. Nevertheless, protamine 1 to protamine 2 ratio (P1/P2), a marker of male fertility, was not altered in sperm of diabetic animals compared to control. Regarding the...
Nuclear dynamics and interactions of myosin 1c
Dzijak, Rastislav ; Hozák, Pavel (advisor) ; Hašek, Jiří (referee) ; Kaňka, Jiří (referee)
1. ABSTRACT Myosins are proteins that convert chemical energy stored in ATP into mechanical force that is applied on an actin filament. Nuclear myosin 1 (NM1) was the first myosin detected in the cell nucleus. Together with nuclear actin they were shown to play important roles in DNA transcription and chromatin remodeling. However, the molecular details of the NM1 functions are largely unknown. To expand our knowledge about this molecular motor we studied tissue expression, mechanism of nuclear localization and molecular interactions of this myosin motor. In the first part we examined the expression pattern of NM1 in various mouse tissues. We demonstrated that NM1 is present in cell nuclei of all mouse tissues examined except for cells in terminal stages of spermatogenesis. Quantitative PCR and western blots demonstrated that the expression of NM1 in tissues varies, with the highest levels in the lungs. NM1 is a nuclear isoform of earlier identified myosin 1c (Myo1c), which was described initially as a cytosolic, and plasma membrane associated protein. The only known difference between these two proteins was the presence of additional 16 amino acids at the N-terminus of NM1. Next we focused on the influence of NM1 domains, including the N-terminus, on the subcellular localization of this protein. We found...
Identifikace genů nezbytně nutných pro normální průběh oplození a preimplantačního vývoje skotu v podmínkách in vitro
Toralová, Tereza ; Kaňka, Jiří (advisor) ; Pěknicová, Jana (referee) ; Ješeta, Michal (referee)
The aim of this work was to find and characterize genes that seem to be important for normal preimplantation development. We characterized three genes in more detail - centromeric protein F (CENPF; mitosin), ubiquitin C-terminal hydrolase-L1 (UCHL1) and nucleophosmin (NPM1; B23; numatrin; NO38). CENPF and nucleophosmin were shown to start their expression at late 8-cell stage, i.e. at major embryonic genome activation (EGA), and were hence supposed to be important during bovine preimplantation development. CENPF plays crucial role during cell division, especially by mediating the interaction of kinetochores and microtubules. Nucleophosmin is a multifunctional nucleolar phosphoprotein, whose most important roles are rRNA processing, chaperoning, ribosome biogenesis and centriole duplication control. Further, we characterized the role of UCHL1 during fertilization of bovine oocytes. UCHL1 is a deubiquitinating enzyme that controls cytoplasmic protein degradation, recycling of free ubiquitin from proteasome products and is involved in regulation of physiological apoptosis. We studied the function of CENPF and nucleophosmin using RNA interference approach. Since UCHL1 protein is very stable, this method is not suitable for studying the UCHL1 function. We thus used two UCHL1 inhibitors that block its...
Transcriptomics of bovine preimplantation embryo genome activation in vivo and in in vitro culture conditions
Vodičková Kepková, Kateřina ; Kaňka, Jiří (advisor) ; Petr, Jaroslav (referee) ; Krylov, Vladimír (referee)
The goal of the thesis was to characterize transcriptional profiles of in vivo and in vitro derived embryos during bovine minor and major embryonic genome activation and to identify mRNA transcripts newly synthesized during these stages. In our first work we have concentrated on the study of minor genome activation at the 4-cell stage of embryo. Using SSH, we have identified 31 amplicons homologous with already identified genes. We have selected 5 of these for detailed study of their expression during the whole period of preimplantation development: centromere protein, 350/400 kDa (CENPF, mitosin), splicing factor arginine/serine-rich 3 (SRFS3), high mobility group nucleosomal binding domain 2 (HMGN2) protein and eukaryotic translation initiation factors EIF4A2 a EIF4E. All these genes play an important role in the early embryo development. SRFS3 is the first described gene with an important function in preimplantation development, which is expressed already during bovine minor genome activation, and its transcription is α-amanitin sensitive during this period. We have selected CENPF gene for a more thorough study. By silencing its expression by the injection of CENPF dsRNA into the zygote, we have studied its function throughout the whole preimplantation development of bovine embryo....
The expression and function of nucleophosmin (B23) during bovine preimplantation development
Benešová, Veronika ; Kaňka, Jiří (advisor) ; Krylov, Vladimír (referee)
Identification of genes that start their expression in different time of embryonal development is crucial for proper understanding of early mammalian embryogenesis. Genes that are differently expressed during this period are supposed to be important for normal preimplantation development. One of these genes is nucleophosmin, the multifunctional protein, which functions among others as a transporting protein between cytoplasm and nucleoli. It is involved in duplication of centrosomes, formation of ribosomes and functions as a chaperoning protein. Nucleophosmin shuttles rapidly between the nucleolus and cytoplasm. Its localization is cell cycle dependent and reflects the development of the nucleoli. For studying the effect of nucleophosmin on the bovine preimplantation development we used RNA interference that causes degradation of the target mRNA after injection of nucleophosmin double-stranded RNA. The average decrease of nucleophosmin mRNA abundance is 86.3 % between nucleophosmin dsRNA injected embryos and control group. We detected no differences in protein expression and localization of nucleophosmin between the groups by immunofluorescence method. Embryos in all groups were able to develop until the blastocyst stage, although there were significant difference between uninjected control group and...
Measurement of amplitude and phase of ultrashort optical pulses by using nonlinear processes in optical fibres
Vraný, Boleslav ; Kaňka, Jiří (advisor) ; Karásek, Miroslav (referee) ; Boháč, Leoš (referee)
I confirm that I worked out this doctoral thesis independently and that I quoted all the literature used. Prohlašuji, že jsem tuto dizertační práci vypracoval samostatně a že jsem uvedl veš- kerou použitou literaturu. V Praze dne 21. 6. 2010 Abstract The thesis deals with the Frequency-Resolved Optical Gating (FROG) method of mea- suring ultrashort optical pulses. As a nonlinear process involved in the method we used cross-phase modulation in a microstructured optical fiber. The FROG device made of fi- ber pigtailed components fitted well the needs of our fiber optical laboratory. The output of the measurement differs significantly from FROG methods that use other nonlinear processes like second harmonic generation. For our FROG, the standard algorithms for reconstruction of the complex envelope from measured spectrogram failed. We therefore used a more robust genetic algorithm (GA) for the reconstruction. GA has several pa- rameters that affect its runs and we explored the influence of these parameters on the success of reconstruction of a number of test pulses and found the optimal set of these parameters. In this work, we present a general discussion of the FROG method and the standard reconstruction algorithms, the experimental setup we used, a discussion of the genetic algorithm, the technical details of our...

National Repository of Grey Literature : 28 records found   1 - 10nextend  jump to record:
See also: similar author names
1 KAŇKA, Jakub
4 Kaňka, Jan
3 Kaňka, Josef
Interested in being notified about new results for this query?
Subscribe to the RSS feed.