National Repository of Grey Literature 104 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
Dynamics of acrosome reaction during intra-specific sperm competition in rodents.
Veselá, Kateřina ; Hortová, Kateřina (advisor) ; Pěknicová, Jana (referee)
Dynamics of acrosome reaction during intra-specific sperm competition in rodents Sperm acrosome integrity is disturbed in promiscuous species field mice (Apodemus) and more than half of the spermatozoa undergoing spontaneous acrosome reaction (AR) before binding to the zona pellucida. In Muridae it is documented a generally high rate of spontaneous AR, and the percentage increases in promiscuous species up to 60 % in 60 min capacitation in vitro. The acrosome integrity positively corellates with presence of CD46 protein which absence in wood mouse is fenotypicaly same as in CD46 knock-out mouse leading to accelerated spontaneous AR. It is necessary to clarify whether for mouse sperm it is essential the primary binding of intact sperm to zona pellucida of the egg or whether it is preferred secondary sperm binding after spontaneous AR. In this context, the question is whether there is a relocalization of the key fusion protein IZUMO in sperm during spontaneous AR. IZUMO relocalization was monitored by immunofluorescence at specific times of capacitation in vitro during spontaneous and induced AR. IZUMO relocalization as closely connected to actin cytoskeleton, and β1 integrins. Dynamics and localization of β1 integrin during spontaneous and induced AR was also detected by immunofluorescence. Our results...
Meiotic sex chromosome inactivation within mouse spermatogenesis
Homolka, David ; Jansa, Petr (advisor) ; Kubelka, Michal (referee) ; Pěknicová, Jana (referee)
Meiotic sex chromosome inactivation (MSCI) is an essential epigenetic process, which transcriptionally silences X and Y chromosomes during spermatogenesis. It is accompanied by substantial chromatin remodeling resulting in a formation of so called sex or XY body, which is a characteristic of male pachytene spermatocytes. In spite of MSCI indispensability for male fertility, its biological role and molecular nature still remain rather unclear. However, the described link between chromosomal asynapsis and transcriptional silencing demonstrated that MSCI is tightly associated with the asynapsis of largely non-homologous sex chromosomes and is a specific form of more general mechanism called meiotic silencing of unsynapsed chromatin (MSUC). The essential role of MSCI was demonstrated using mouse models, such as carriers of X- autosome translocations, where anomalous synapsis of sex chromosomes leads to impairment of MSCI and male sterility. Intriguingly, the exclusive spermatogenic arrest is a hallmark of not only X-autosome translocations but even various autosomal rearrangements, including autosomal translocations, inversions, or other structural mutations. Because the rearranged autosomes often intimately associate with the sex body, it...
The role of immune system factors in IVF/ET success
Růžičková, Žaneta ; Madar, Jindřich (advisor) ; Pěknicová, Jana (referee)
5 Abstract The aim of this study was to evaluate the presence of receptors (CD16, CD161, NKG2D, KIR2DL4 and CD85j) on the surface of immunocompetent cells and whether their presence is involved in the in vitro fertilization (IVF) and following embryotransfer (ET) success. We observed significant difference in the age of successful versus unsuccessful patients, which is confirmed by former studies on age-dependence of IVF success. The result from cytotoxic assay confirmed, that neither the stimulation protocol, nor the PBMC source have any effect on effector function. Afterwards, we performed a large-scale analysis of surface markers, starting with healthy donors, compared to patients. Both groups of patients have lower counts of HLA-G binding KIR2DL4 or CD85j receptors bearing cells. Next we observed the expression of these two receptors on various subpopulations of cells (CD56+dim , CD56+bright , T helpers and cytotoxic T cells) and their counts. Here we observed differences in CD56 surface expression on CD56+ bright NK cells, the levels of CD56+dim NK cells in PBMC (CD16 expression on this population), levels of CD56+dim Next step was to compare the levels of cell populations between the successful and unsuccessful patients. We observed an increased surface expression of KIR2DL4 on lymphocytary PBMC of...
The Role of Energetic Metabolism in the t-haplotype Transmission ratio distortion
Marvanová, Hana ; Paulasová, Petra (advisor) ; Pěknicová, Jana (referee)
When two alleles carried by a heterozygote are transmitted unequally to the zygote at the time of fertilization, transmission ratio distortion occurs. The best studied example of this phenomenon in mammals is t-haplotype in mice. The mouse t-haplotype is a selfish variant region on chromosome 17, in nature transmitted as a unit. Male mice homozygous for t haplotype are sterile, but heterozygotes transmit the t haplotype up to 99% of their progeny. This is believed to be caused by motility differences between sperm carrying the t haplotype and wild-type sperm from the same heterozygous male. The concrete mechanism of the postulated sperm competition in favour of t haplotype carrying sperm was so far not fully illuminated. During this project, we worked with the hypothesis that the differences in sperm motility putatively responsible for transmission ratio distortion are triggered, at least in part, by metabolic causes. Our results from ATP and mitochondrial membrane potential (MMP) comparison indeed suggest that there are metabolic dissimilarities in sperm from the different genotypes of t (t/t, t/+, +/+). Specifically, our data show that there is significantly less ATP in t/t sperm when compared to the other two genotypes. Likewise, sperm from t/t mice also seem to have lower MMP, suggesting that...
Recombinant Fragments of Antibodies
Král, Vlastimil ; Sedláček, Juraj (advisor) ; Pěknicová, Jana (referee) ; Hašek, Jindřich (referee)
6. CoNct usloN The aim of the thesis was to establish, in the national conditions, technology of preparation of antibody reconrbinant fragrnents and to verífo the cornplete procedure using several model monoclonal antibodies with a potential diagnostic and therapeutic use. For tfuee antibodies' mAb TU-20, M75 and MEM97, recombinant |Ťagments in various formats (scFv fragments monovalent and bivalent, i.e. diabody, and intrabody for intracellular expression) were constructed and for their heterologous expression, vectors allowing expression in E. coli (as cytoplasmic inclusions, periplasmic inclusions and in soluble form) and in Drosophila 32 cells (expression of glycosylated forms of scFv fragments into the medium) were used. In case of proteins expressed in irrsoluble form, especially scFv F|1.2.32, renaturation procedures to obtain active scFv fragments were developed and optimized. The efnect of the length of the linker -(GlyrSer).- (where x is I to 4) connecting the variable domains of the light and heavy chain on the formation of different multimeric forms of scFv rvas studied. For obtaining solell monomeric scFv fragment, the length of 20 amino acid residues tumsd out optimal. Fragnrents rvith a linker l5 residues long. formed a mixture of monomers, dimers and trimers. the proportion of rvhich rvas...
Effect of cryopreservation on mouse sperm.
Veselá, Kateřina ; Hortová, Kateřina (advisor) ; Pěknicová, Jana (referee)
Cryopreservation or freezing of sperm in the reproductive biology is still actual topic. Today is the only method used for sperm storage, whether for the purposes of assisted reproduction, or for scientific purposes. However, this method has a negative impact on such stored cells and is therefore still a subject of many studies. Among the main causes of sperm damage in rodents there are inappropriately selected cryoprotective agents, poor or no elimination of oxidative stress generated during cryopreservation, as well as a poorly chosen speed and temperature of freezing. Correctly chosen procedures and the composition of the media in which sperm are stored, can significantly affect the quality of sperm. This bachelor theses focuses on the influence of cryopreservation on mouse spermatozoa. The main impact of this method includes the effect of freezing on sperm DNA, plasma membrane, acrosome, and sperm motility.

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