National Repository of Grey Literature 34 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
The role of centrobin in spermatogenesis
Flintová, Jennifer ; Komrsková, Kateřina (advisor) ; Šebková, Nataša (referee)
Spermatogenesis is a highly orchestrated, strictly regulated cascade of events that could be divided into three major processes: mitotic expansion of diploid germ cells (spermatocytogenesis), meiotic division creating haploid cells, and spermiogenesis. Spermiogenesis, the final stage of spermatogenesis comprises a striking metamorphosis of round haploid spermatids into morphologically and functionally specialized spermatozoa designed for the fertilization. One of the proteins indispensable for proper sperm morphogenesis is centrobin, a structural component of the specialized cytoskeletal structures of the elongating spermatids (acroplaxome and manchette), executing essential role in sperm head shaping and assembly of the head-tail coupling apparatus. Disruption in Cntrob gene (coding for centrobin) in rats homozygous at the hd (hypodactyly) locus results in male infertility, with a striking morphological signature called "decapitated sperm syndrome" with detachment of sperm head from the flagellum due to impaired head-tail coupling. However, molecular function of centrobin in spermiogenesis is still unknown. Sperm decapitation is a distinct phenotype described in several mouse mutants and importantly from infertile human males. Strikingly, in addition to proteins functioning in cytoskeletal...
Fc receptor-like molecules: biological role and phylogenetic conservation of FcRL multigene family
Böhmová, Helena ; Komrsková, Kateřina (advisor) ; Vinkler, Michal (referee)
Fc receptor-like (FcRL) molecules are novel immunological receptors with intriguing proposed roles in the immune system. Phylogenetic studies revealed that FcRL genes are conserved in jawed vertebrates (Gnathostomata), and likely formed during adaptive system genesis. FcRLs have multiple extracellular immunoglobulin domains, and some representatives have newly documented specific ligands. Several FcRLs contain both ITIM and ITAM cytoplasmatic sequences, which provide them with dual signalling properties. These allow them to regulate intracellular signalling pathways. FcRLs are known to engage in B cell regulation. They are largely expressed on B cells, with some representatives preferentially expressed on cytotoxic T cells and NK cells. Their expression patterns are specific to distinct B cell subpopulations and also show different levels of expression during B cell differentiation, pointing to their possible involvement in this process. FcRL molecules have also been detected on the mammalian eggs, and they may potentially play role in gamete fusion. This thesis aims to introduce FcRL molecules in various aspects, including their relation to classical Fc receptors, their structural properties, genomic organisation, phylogenetic conservation and their roles in organism. Thesis also focuses on...
The role of LINC complex in male germinal cells
Kmoníčková, Věra ; Komrsková, Kateřina (advisor) ; Knop, Filip (referee)
LINC (linker of the nucleoskeleton and cytoskeleton) complex is substantial for the overall function of any nuclear cell. It is a bridge between the cytoplasmic and nuclear structures which mediates transmission of mechanical forces generated on the cytoplasmic side. The main objective of this thesis is the function of distinct variants of the LINC complexes in mammalian male germinal cells throughout their development. The nuclear facing side of the LINC complex is a key player in homolog pairing and rapid chromosome movements during meiosis. The cytoplasmic facing side is necessary for the sperm head formation, proper acrosome and nucleus attachment. Evenly, another complex is essential for the head-to-tail coupling as without this one the sperm cells are found decapitated. If the subunits of the LINC complex are defective, males are afflicted with different kinds of infertilities, which nowadays is one of the important issues of our society. Many things about the role and structure of the LINC complex has been discovered due to modern technologies. These up to date findings are summarized and discussed on the following pages.
LINC complex: The link between chromatin integrity and sperm motility
Šanovec, Ondřej ; Komrsková, Kateřina (advisor) ; Lánská, Eva (referee)
The LINC complex (Linker of the Nucleoskeleton and Cytoskeleton) is a protein structure located in the nuclear membrane that connects the cytoskeleton with the nucleoskeleton. This complex can be found in every mammalian cell including the gametes. However, here the LINC complex is more diverse and less studied than in the somatic cells. In this thesis, the LINC complex and its role in spermiogenesis have been studied in wild-type and Protamine 2 knockout (Prm2-/- ) mice. Protamines are small proteins that replace histones during spermiogenesis. The mouse model generated by the group of prof. Hubert Schorle has a deletion in Prm2 in exon 1 and its sperm possess a surprising phenotype including complete loss of motility. Therefore, it was hypothesized that the LINC complex might be responsible for miscommunication between the sperm head and tail which leads to the loss of sperm motility. Results from this study suggest that the LINC complex is not influenced by Prm2 deletion, however, actin dynamics, cytoskeletal motor proteins and tubulin acetylase/ histone deacetylase activity might be impaired. Prm2-/- sperm have a significantly higher abundance of β-actin compared to the wild type. Next, Prm2-/- sperm also show a different pattern of acetylation of α-tubulin but no change in the abundance of...
Dextran polysaccharides and seminal plasma proteins in boar sperm cryopreservation
Šimoník, Ondřej ; Tůmová, L. ; Bubeníčková, F. ; Sur, Vishma Pratap ; Frolíková, Michaela ; Postlerová, Pavla ; Komrsková, Kateřina
The unique design of a methodical approach to testing cryoprotective components will be used in specialized research institutes or universities, including commercial development bodies in the field of animal reproductive biotechnology. The methodology includes a completely detailed and unique protocol based on many years of experience in the field of proteomics and can be used for further progress testing cryoprotectants for breeding programs of individual species or livestock breeds as regards the importance of retention of genetic resources.\n\n
Chemical communication of gametes
Otčenášková, Tereza ; Komrsková, Kateřina (advisor) ; Petr, Jaroslav (referee)
Fertilization is a multiple step process leading to fusion of female and male gametes resulting in a formation of a zygote. Besides direct gamete interaction via binding receptors localized on both oocyte and sperm surface, fertilization also involves communication based on chemical molecules triggering various signalling pathways. This work is aimed to characterize chemical communication of gametes of a model organism Mus musculus. For this purpose, modern proteomic and visualisation methods like nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS), selected reaction monitoring (SRM) and immunofluorescent microscopy were used. Lipocalins were identified as candidate proteins involved in communication including those from major urinary proteins (MUPs), LCN lipocalins and fatty acid binding proteins (FABPs). For the first time, we report their presence in the sperm acrosome. Based on lipocalins capacity to bind and transport other molecules, we propose that these proteins have a protective and/or signalling role for gametes. Furthermore, chemical communication between sperm and oocyte is based on chemotaxis which enables their interaction before their fusion. In this work, we detected that spermatozoa show chemotactic responses in the presence of L-glutamate. This amino acid naturally...
Male fertility disorders and sperm damage related to COVID-19 disease.
Pikulová, Simona ; Komrsková, Kateřina (advisor) ; Ješeta, Michal (referee)
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the coronavirus disease 2019 (COVID-19), which has spread rapidly worldwide since the end of 2019. The virus causes serious health problems and damage to human organs, especially the lungs, kidneys, brain, heart and testicles, which can be fatal. This work deals with the entry of SARS- CoV-2 virus into the testicles and sperm damage due to infection. Receptors are described in more detail, specifically the membrane receptor ACE2, which mediates the entry of the virus into germ cells (spermatogonia) and somatic testicular cells (Sertoli and Leydig), which express this receptor. In this work, the mechanisms causing infection are described and attention is focused to changes in the signaling pathways due to SARS-CoV-2 and ACE2 binding. Consequently, the presence of the virus leads to hormonal imbalances, local oxidative stress and inflammation, which affect the course of spermatogenesis and can cause pathological conditions of spermatozoa such as motility disorders or DNA fragmentation and thus adversely affect male fertility. Key words: COVID-19, SARS-CoV-2, male infertility, sperm, ACE2
Cytoskeleton-membrane protein interaction network in sperm
Adamová, Zuzana ; Komrsková, Kateřina (advisor) ; Tolde, Ondřej (referee)
In order to fertilize the egg, sperm cell undergoes several subsequent maturation processes. The final one called acrosome reaction is an exocytosis of acrosome vesicle, which is filled with lytic enzymes. Acrosome reaction is crucial for penetration of the sperm cell through the egg surroundings, especially zona pellucida, as well as for reorganization of a membrane protein composition on its surface. This rearrangement leads to the exposure of proteins essential for fertilization, mainly for gamete recognition, binding and fusion in specific compartments of the sperm head. One of such protein is CD46, which is located in the acrosomal membrane of an intact sperm and after acosomal exocytosis it relocates to the equatorial segment of a sperm head, which is known to be the initial site of interaction of sperm with the egg plasma membrane. The relocation of CD46 is disrupted by inhibition of actin, which reorganization within sperm head is known to play a role in onset of acrosome reaction, however, the precise mechanism of CD46 interaction with actin in sperm is unknown. In this thesis, ezrin - a crosslinker of membrane proteins and actin - has been studied in context of CD46 and its relocation across the sperm head. Analysis of the immunofluorescent detection of ezrin revealed its mutual...
Monitoring of protein network dynamics: the role of FcRL proteins during sperm-egg membrane interaction
Bašus, Kryštof ; Komrsková, Kateřina (advisor) ; Šušor, Andrej (referee)
Sperm-­-egg membrane interaction and fusion is mediated by various molecules of the different protein network that are located on both egg and sperm membrane. So far, many proteins have been selected to be fusion candidates, some of them (Izumo1, CD9, Juno) were proven to be essential, whereas others were discovered to play an unsuspected new active role (CD46, tetraspanins). After the adhesion of sperm to an egg, Juno located on the oolema associates with monomeric Izumo1 on sperm membrane, which is results in Izumo1 dimerization following quick removal of Juno from the egg surface as described in mouse. It implies that additional receptor on the egg membrane is required to play a role in sperm-­-egg fusion. To find a human fusogenic receptor for IZUMO1 protein we used one-­-bead-­-one-­-compound (OBOC) assay, a random screening approach. A bead, fulfilling all the requirements when interacting with the human sperm, carried a peptide sequence showing homology with the conserved Ig domain of the human specific Fc receptor-­-like protein 3 (FcRL3). In general, the ...

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