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Molecular basis of the sperm selection in the mammalian female reproductive tract
Šrámková, Adéla ; Krylov, Vladimír (advisor) ; Postlerová, Pavla (referee)
Internal fertilization is typical for all mammals. The male transfers sperm cells into the female reproductive tract, where usually one of them reach the oocyte and fertilize it. The female reproductive tract must be adapted to provide a suitable environment for the sperm cells to survive until fertilization. On the other hand, it must also be able to select developmentally competent sperm cells and prevent others to get into the close contact with the oocyte. Physical and molecular mutual communication of sperm cells with the female reproductive tract is ensured by sperm surface molecules and the receptors of the female epithelia lining. It appears that these interactions are required for key transformations, both on the sperm surface and in the cells of the female reproductive tract, where gene expression is affected. As a result of these changes, the most suitable sperm cell with all the required characteristics is allowed to fertilize the matured oocyte.
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Aggregation of bull seminal plasma protein
Boháček, Hanuš ; Liberda, Jiří (advisor) ; Hýsková, Veronika (referee)
Mammalian fertilization is a sequence of unique and fascinating events, during which seminal proteins are of crucial role. In case of bull (Bos taurus), proteins of seminal plasma (BSP), especially its major component PDC-109, are known to be in aggregated forms, but little is known about mechanism of forming aggregates and their biological function. In present thesis we discovered some interesting properties of PDC-109 and BSP proteins. We found that concentration of these proteins influences their aggregation state significantly, which can be of great biological importance. Separation of seminal proteins by size exclusion chromatography revealed three main fractions denoted I, II and III, with apparent molecular weights of Mr > 150 000, Mr = 30 000 and Mr = 13 000, respectively. In case of PDC-109, molecular weights of theese fractions were retained even after purification procedure, which implies very stable interactions in forming of aggregates. In addition, there was a difference in distribution of PDC-109 glycoforms among fractions, which can be related to the fact, that theese fractions have different sperm membrane binding patterns as we determined by fluorescence microscopy. However, further experiments are needed for better understanding this issue.
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The role of integrins in gametes prior to fertilization and during their interaction
Foldynová, Veronika ; Komrsková, Kateřina (advisor) ; Tlapáková, Tereza (referee)
Integrins are heterodimeric transmembrane glycoproteins that represent a large group of cell adhesion receptors involved in cell-cell, cell-extracellular matrix and cell-pathogen interacti- ons. Up to now, 24 different integrin heterodimers have been detected in mammals. They are involved in a wide range of processes such as immune response, lymphocyte homing, platelet aggregation, also in wound healing, cell differentiation, migration, proliferation and even in cell survival. Integrins have also been detected on germ cells and are now known to play an important role in reproductive processes such as fertilization, embryo implan- tation, and embryonic development. The main aim of this thesis is to introduce integrins from the perspective of reproduction, integrin physiology, occurrence and localization of individual subunits in male and female germ cells. A significant part of the work is devoted to a discussion of the role of integrins in gametes, both during maturation processes (egg maturation in the ovary, capacitation and the acrosomal reaction of sperm), in sperm mi- gration, oviductal reservoir formation and their direct and indirect involvement in adhesion and fusion of the gametes during fertilization. Keywords: integrins, sperm, egg, fusion, fertilization
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Species-specific structural differences of mammalian sperm and function of their key proteins during fertilization.
Dobrodinská, Anna ; Frolíková, Michaela (advisor) ; Kuntová, Barbora (referee)
The fertilization is a process during which a male and a female gamete merge so that a new organism may come into being. The sperm-egg fusion is preceded by several essential processes, such as the capacitation, acrosome reaction, the sperm binding to the zona pellucida and oolemma, and membrane fusion of the gametes. Numerous proteins, which are located in both sperm and eggs, are major actors in controlling the listed, essential processes. During the process of fertilization these proteins fulfil one or more functions. In mammalian sperm, significant species-specific differences may be found both in their morphology and at the protein level. A complex understanding of species-specific distinctions in sperm structure and functions of key sperm proteins would contribute to a better insight into the process of fertilization, thereby enabling us to better diagnose and subsequently treat the causes of infertility in humans. This bachelor's thesis summarizes the current knowledge of sperm structure and its key proteins that has been acquired through the studies of the following model mammal species: bull, boar, mouse, and human. Further, this thesis brings an interspecific comparison between the studied species. Keywords: sperm, fertilization, acrosome reaction, capacitation, sperm proteins, bull,...
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Gametogenesis and Fertilization in Humans
Crhová, Michaela ; Pavlasová, Lenka (advisor) ; Ehler, Edvard (referee)
This bachelor thesis summarises the topic of gametogenesis and fertilization in humans. A search in available literature was performed. The thesis concisely describes the cell cycle and cell division. The main focus is on meiosis, a reductional division that takes the lead part in sexual reproduction. The process of this division is described in detail, and also the mechanism that creates variability of protected cells is described. The product of meiosis is gametes, also known as germ cells. Production of these cells is a key moment in sexual reproduction. This thesis approaches this topic in the context of evolutionary biology and explains its importance in the survival of species on Earth. The main topic of the thesis is the production and maturing of human germ cells. This process is called gametogenesis. This thesis provides a cohesive description of the reproduction system of both sexes and describes the gradual maturing of the germ cells in gonads. The structure of both gametes, egg, and sperm is described with emphasis on the parts of these cells that take part in the process of fertilization. Female reproductive cycles are depicted, and their connection is explained. In contrast to this periodicity, the male continual maturing is also explained. This thesis compares the main differences in...
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The role of integrins in gametes prior to fertilization and during their interaction
Foldynová, Veronika ; Komrsková, Kateřina (advisor) ; Tlapáková, Tereza (referee)
Integrins are heterodimeric transmembrane glycoproteins that represent a large group of cell adhesion receptors involved in cell-cell, cell-extracellular matrix and cell-pathogen interacti- ons. Up to now, 24 different integrin heterodimers have been detected in mammals. They are involved in a wide range of processes such as immune response, lymphocyte homing, platelet aggregation, also in wound healing, cell differentiation, migration, proliferation and even in cell survival. Integrins have also been detected on germ cells and are now known to play an important role in reproductive processes such as fertilization, embryo implan- tation, and embryonic development. The main aim of this thesis is to introduce integrins from the perspective of reproduction, integrin physiology, occurrence and localization of individual subunits in male and female germ cells. A significant part of the work is devoted to a discussion of the role of integrins in gametes, both during maturation processes (egg maturation in the ovary, capacitation and the acrosomal reaction of sperm), in sperm mi- gration, oviductal reservoir formation and their direct and indirect involvement in adhesion and fusion of the gametes during fertilization. Keywords: integrins, sperm, egg, fusion, fertilization
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Methods of sperm selection for human and veterinary assisted reproduction
Pavlová, Hana ; Komrsková, Kateřina (advisor) ; Koubek, Pavel (referee)
Sperm selection is an important process influencing the progress of fertilization and the quality of resulting embryos. Competent sperm cells can be isolated from an ejaculate sample according to different criteria. Standard methods allow for sperm selection based on conventional parameters, particularly motility and density. Using advanced methods, sperm cells are selected according to molecular aspects including for instance membrane charge, presence of specific receptors, molecules indicating ongoing apoptosis, and others. The latter procedures are widely used particularly in human practice. Their use is uneconomical in veterinary practice and standard methods including the centrifugation step in the procedure are primarily used to select the sperm of livestock. Sperm cells of livestock are also often selected according to whether it carries the X or Y chromosome. Thus, the sex of the offspring can be effectively determined in order to increase the efficiency of the production of animal products. This thesis presents the most frequently used methods of sperm selection for the purpose of oocyte fertilization in human and veterinary sectors of assisted reproduction and discusses their impact on the parameters and fertilization potential of isolated cells.
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Sperm centrioles and their role in reproduction
Vlčková, Monika ; Frolíková, Michaela (advisor) ; Liška, František (referee)
Centrioles are evolutionarily conserved protein structures composed of microtubules. In somatic cells, centrioles serve as the basal body of cilia and flagella and allow the assembly of pericentriolar material, thereby creating the centrosome. Without centrosome, animal cells are not capable of nuclear division. Centrioles do not arise de novo and their formation always requires the presence of a preexisting centriole. Since there are no centrioles in the egg at the time of fertilization, unlike spermatozoa, sperm is the carrier of centrioles and therefore all of the centrioles of the emerging organism are of paternal origin. There are two centrioles in the sperm - a cylindrical shape proximal and a distal one, which is perpendicular to the proximal. The sperm centrioles are the basis for the formation of the sperm flagellum and after fertilization form the mitotic spindle of the zygote, necessary for equal DNA and cell distribution. It follows from the above that the presence of centrioles in sperm is essential in mammals and defects in their structure may lead to male sterility or embryo development disorders. However, sperm centrioles differ from somatic centrioles in their structure and behavior and understanding these differences is one of the important tasks of reproductive biology.
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Sperm cell penetration and membrane fusion with oocyte during fertilization in mammals
Klimková, Veronika ; Krylov, Vladimír (advisor) ; Frolíková, Michaela (referee)
Fertilization is a process involving multiple steps, which are in continuity and complement each other. Spermatozoa become competent to fertilize after capacitation, hyperactivation and acrosome reaction. Oocytes are surrounded by a layer of cumulus cells and give a signals for spermatozoa to activation and orientation. This study focuses on the latest knowledges about a roles of cumulus cells, production of chemoattractants and the possibility that cumulus cells induce the acrosome reaction after binding a novel sperm protein NYD-SP8 to the cumulus. It seems that progesterone induce the acrosome reaction and also is the best chemoattractant secreted by cumulus cells. Next I am focus on gamete fusion including the role of surface proteins such as Juno and IZUMO1. Key words: membrane fusion, cumulus cells, acrosome reaction, chemotaxis sperm, oocyte, fertilization
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Immunological causes of female infertility
Bajerová, Kateřina ; Brynychová, Iva (advisor) ; Novák, Jan (referee)
Currently, up to 15 % of reproductive age couples struggle with infertility. Female infertility is the cause of conception issues in nearly 40 % of these cases. The origin of female infertility consists of wide range of causes and other factors. Immunological causes are certainly one of the most significant ones. In pathological conditions, defense mechanisms of female immune system can target alloantigens presented on sperm surface. Moreover, autoimmune response and antibody production can occur as well. Antibodies can target various parts of ovarian follicles and oocytes, phospholipids, nuclear antigens, enzymes etc. These antibodies can inhibit fertilization, maturation of oocytes and embryo, embryo implantation, and also recurrent miscarriages. The aim of this thesis is to summarize various causes of female infertility focusing on immunological pathologies. The thesis also describes functioning of immune mechanisms in the female reproductive tract and briefly touches on oogenesis and female hormonal cycle.
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