National Repository of Grey Literature 43 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Chemical communication of gametes
Otčenášková, Tereza ; Hortová, 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...
Cytoskeleton-membrane protein interaction network in sperm
Adamová, Zuzana ; Hortová, 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...
Male infertility in context of testicular cancer
Cimlerová, Markéta ; Hortová, Kateřina (advisor) ; Truksa, Jaroslav (referee)
This bachelor thesis focuses on male infertility in a connection to testicular cancer. Testicular cancer is the most common malignancy among young men in a reproductive age and the worldwide incidence of testicular cancer is on the rise. A lot of attention is also given to an increasing rate of infertility in a context of testicular cancer. For these reasons, the aim of this thesis is to clarify several non-physiological changes, such as hormone levels, spermatogenesis and sperm parameters, which take place in a male body and influence the chance to become a biological father. These pathological changes can be due to the disease itself but also due to the treatment. A cryopreservation of semen is also going to be discussed as the way to preserve male fertility and as an option for couples with the infertility problems due to male factor which rely on help of the assisted reprodiction. Kye words: testicular cancer, cancer treatment, male infertility, sperm parameters, mitochondria, assisted reproduction
Sperm competition in frogs in relation to the reproductive strategy
Malečková, Vendulka ; Šandera, Martin (advisor) ; Hortová, Kateřina (referee)
2 Abstract This bachelor thesis focuses the comparison of the various reproductive strategies of frogs and the degree of sperm competition. Frogs are ecologically important group inhabiting all continents except Antarctica and northern polar regions. Frogs have species-specific reproductive strategies. Most frogs have external fertilization, but there are exceptions (eg. Ascaphidae) with internal fertilization. Before mating occurs, male grips female - this is called amplexus. Amplexus is divided into several types according to the place of gripping the female, and there are exceptions that do not use amplexus. Even for them there is a complex behavior, in which the male directs the female to the eggs laying spot. Mating mostly occurs in water. Frogs are polyandrous, meaning that one female mates with multiple males. Such a system encourages the male-male competition, as well as the sperm-competition. Breeding of frogs can be classified as explosive or prolonged. Clutches of eggs are being laid by females into water or foam nests. In some cases the male takes part in taking care of the clutch, nest building, or they steal other clutches. In conclusion, it is discussed whether there is a connection between specific reproductive strategies and levels of sperm competition. Key words: amplexus, clutch-piracy,...

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