National Repository of Grey Literature 55 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
In vitro fertilization in horses
Müller, Filip ; Šušor, Andrej (advisor) ; Šimoník, Ondřej (referee)
Reproductive management in horse breeding increasingly relies on in vitro fertilization (IVF) techniques. This technology entails a complex process, including the acquisition of immature oocytes, their in vitro maturation, fertilization with sperm, and subsequent cultivation of the early embryo before transfer into a synchronized recipient. However, the success of equine IVF is influenced by various factors such as oocyte quality, sperm capacitation, and technical issues unique to this process, compared to other mammalian models. This bachelor's thesis aims to summarize and evaluate current knowledge on IVF of horse eggs, identify key factors influencing success, and describe current procedures for gamete preparation. By incorporating the latest IVF approaches and optimizing them, a higher success rate can be achieved. Key aspects for improving equine IVF include gamete collection and handling, in vitro oocyte maturation, sperm capacitation, and subsequent embryonic development.
Endocrine disruptors and their impact on mammalian oocyte developmental competence
Štenglová, Anna ; Němcová, Lucie (advisor) ; Ješeta, Michal (referee)
Endocrine disruptors (EDs) are defined as substances of exogenous origin that disrupt endocrine system. EDs are found in significant amounts in the natural environment, plastic products and flame retardants, leading to unavoidable exposure. Due to their broad effects, several organizations/ conventions aim to regulate their presence in the natural environment and limit, or even eliminate their production. By entering the body, they negatively affect development, reproductive, nervous or immune systems of various animal classes through hormones. Modified hormonal levels are associated not only with fertility issues, but also with physiological abnormalities, osteoporosis, depression or metabolic diseases. EDs affect the female reproductive system through hormonal modifications of the HHG axis, which can lead to an earlier pubertal onset in some cases. Under the influence of EDs, impairments can also be observed in the process of steroidogenesis, development of follicles and oocytes, particularly through meiotic defects, which can lead to premature ovarian failure or infertility. Multiple chemicals disrupt the females reproductive system across several generations through epigenetic effects. This work summarizes knowledge about these ubiquitous substances and their impact on female reproductive...
Annulate lamellae and their role in viral infection
Doležal, Vojtěch ; Bruštíková, Kateřina (advisor) ; Vopálenská, Irena (referee)
Annulate lamellae are subdomain of endoplasmatic reticulum made of lipid membrane. This membrane has inserted pore complexes structurally and spatially similar to the nuclear pores. Annulate lamellae naturally occur in germ cells, but their formation can be induced even in cell types in which they naturally do not occur. They significantly participate in nuclear assembly after cell division. They also participate in regulation of Ca2+ release from endoplasmatic reticulum into the cytoplasm. Annulate lamellae formation is also induced by infection by some viruses. The first part of this work summarizes the history of annulate lamellae, their occurence in different cell types, localization within cells, their structure and fuction. Second part of this work summarizes the occurence of annulate lamellae in virus infected or transformed cells and their function in viral infection if it is known. Keywords: Annulate lamellae, pore complex, nucleoporin, oocyte, virus, endoplasmatic reticulum
Effect of triclosan on in vitro meiotic maturation of porcine oocytes
Straková, Johana ; Petr, Jaroslav (advisor) ; Frolíková, Michaela (referee)
Meiotic maturation of oocytes is a key phase in the development of female gametes. The natural physiology of oogenesis and meiotic maturation is currently being influenced by a number of anthropogenic environmental contaminants. These compounds include triclosan. Triclosan (5- chloro-2-(2,4-dichlorophenoxy) phenol) is an antibacterial substance commercially used in cosmetic and disinfectant products. This compound enters the human body by absorption through the skin and mucous membranes. Its presence has been demonstrated in blood, urine, breast milk, liver and adipose tissue. Triclosan is classified as an endocrine disruptor, yet its consumption continues to increase worldwide. The aim of this study is to evaluate the effect of low doses of triclosan on selected markers of meiotic maturation of porcine oocytes in vitro. This work describes the negative effects of triclosan and triclosan in combination with bisphenol S on the meiotic maturation of porcine oocytes in vitro. Furthermore, the effect of these substances on the increased percentage of abnormal meiotic spindles and the stability of the microtubules of the meiotic spindle was demonstrated. Effects on mitochondria and epigenetic effects of triclosan were not proved. The results highlight the risks associated with the commercial use of...
Charakterizace oocytů afrických rypošů
This study is focused on characterisation of oocytes of long-lived rodents, naked mole-rat and giant mole-rat, that are emerging models of long-term oocyte and ovarian quality. In the second part, the effect of repeated ovulations on aging-associated quality decline of oocyte is studied, comparing mouse and giant mole-rat.
Bioinformatic analysis of RNA dynamics during mammalian oocyte-to-embryo transition
Horvat, Filip ; Svoboda, Petr (advisor) ; Bruce, Alexander (referee) ; Vioristo, Sanna (referee)
The oocyte-to-embryo transition (OET) is a complex biological process during which a terminally differentiated oocyte undergoes numerous and coordinated changes to emerge as a collection of totipotent cells - initial blastomeres of a preimplantation embryo. In mammals, this process is primarily controlled through post-transcriptional regulation of maternal RNAs and transcriptional induction of zygotic RNAs. Technological advancements of next-generation sequencing methods during the last decade enabled studying OET through bioinformatic studies of high-throughput transcriptomics and genomics datasets. The work presented in this thesis explores mechanisms of post-transcriptional regulation and dynamics of different RNAs during OET by utilizing in-depth computational analyses. The presented work is divided into three topics, all covering distinct regulatory facets of the mammalian OET and illustrating roles of different RNA species. The first topic discusses dynamics of maternal transcriptomes in mouse. In our research, we explored roles of deadenylase CNOT6L in the maternal mRNA turnover in mice. We provided evidence that animals deficient in Cnot6l expression are subfertile, due to disruption in deadenylation and degradation of maternal mRNAs deposited in the oocyte. In another study, we...
Ezrin-Radixin-Moesin (ERM) proteins: The link between tetraspanin web and cytoskeleton in gametes
Picková, Jana ; Frolíková, Michaela (advisor) ; Lánská, Eva (referee)
Ezrin, which belongs to the ERM protein family along with radixin and moesin, plays an important role in linking membrane proteins to the actin cytoskeleton. In sperm, ezrin was described so far in bovine and humans, where it probably contributes in actin polymerization during capacitation. During the acrosome reaction, actin plays a significant role in relocation of protein from the inner acrosomal membrane to the equatorial segment, which is an essential process for successful fertilization. One of the proteins that relocates to the equatorial segment, the site of initiation of gamete fusion, is protein CD9. This protein probably stabilizes protein interactions between sperm and oocyte during gamete fusion. In this diploma thesis, we focused on the role of ezrin in linking the CD9 protein to the actin cytoskeleton in mouse sperm. Using indirect immunofluorescence, we detected ezrin, CD9 and actin in acrosome intact mouse sperm. The co-localization of these proteins in the apical acrosomal region suggests their interactions. However, this was not confirmed by our co-immunoprecipitation experiments. Nevertheless, in the apical acrosomal region we also detected EWI-2 protein, which could act as linker between CD9 and ezrin. In this thesis, we also investigated changes in levels of active...
The effect of Bisphenol S on porcine oocyte meiotic maturation
Kosařová, Zuzana ; Petr, Jaroslav (advisor) ; Kaňka, Jiří (referee)
Meiotické zrání je klíčovou fází vývoje samičích gamet. Do regulace procesu zrání mohou negativně zasahovat látky, které vstupují do organismu z vnějšího prostředí a následně narušují homeostázu na úrovni hormonálního řízení. Tyto látky se označují jako endokrinní disruptory (ED). Mezi nejrozšířenější ED patří bisfenoly. Po prokázání ED aktivity a právních regulacích využití bisfenolu A značně stoupla světová produkce bisfenolu S (BPS). Recentní studie potvrzují negativní vliv BPS přítomného v organismu na reprodukci lidí a zvířat. Přesto zůstává řada dopadů BPS na oogenezi stále nejasná. Tato práce je zaměřena na hodnocení vlivu BPS na vybrané markery rozpadu jaderné membrány v průběhu rozpadu zárodečného váčku (lamin A/C, lamin B1 a LEMD3) a na přeskupování chromatinu po výstupu prasečích oocytů z I. meiotického bloku. Výsledky prokazují negativní vliv BPS na průběh meiotického zrání zrychlením či zpomalením dějů, které souvisejí s rozpadem jaderné membrány a na nutnost se tímto tématem dále zabývat. Klíčová slova endokrinní disruptor, bisfenol S, meiotické zrání, rozpad jaderné membrány, oocyt
The role of cumulus cells during the maturation of mammalian oocytes
Meniuková, Kateřina ; Krylov, Vladimír (advisor) ; Drutovič, David (referee)
Cumulus cells in the ovarian follicles emerge by differentiation from somatic granulosa cells. They are located around the oocytes in stratified clusters and their innermost layer is called the corona radiata. Cytoplasmic microvilli of cumulus cells pass through zona pellucida to the proximity of the oolema, where formation of gap junctions enables signalling and metabolic codependency. Oocytes produce factors affecting processes in cumulus cells, including their metabolism and viability. By modulating the abundance of cyclic nucleotides in oocytes, cumulus cells allow the maintenance of meiotic arrest, providing time for oocytes to finish their growth and gain competence for maturation. Because oocytes have a very limited ability to process glucose, metabolic cooperation with cumulus cells enables them to gain the energy needed for processes associated with growth and maturation. Several metabolic pathways of glucose processing create energy substrates for the formation of ATP, which they then transport to the oocytes. They also regulate the amount of lipid droplets in oocytes and protect them from cellular toxicity. An increase in the concentration of luteinizing hormone in the follicle just before ovulation induces the transmission of the signal for cumulus expansion. Interruption of the...
Creation and analysis of conditional knock-out CDK12 for the study of female reproductive ability
Sedmíková, Veronika ; Šušor, Andrej (advisor) ; Frolíková, Michaela (referee)
Oogenesis is a process with a complex interplay of changes at the genetic, cellular, and structural levels that should lead to the differentiation of female gametes. Strict regulation of these processes is required, as any disruption can lead to fertility problems or disabilities in the offspring. The aim of this work is to gain further insight into the processes that influence oocyte development. This work focuses on cyclin-dependent kinase 12 (CDK12), which belongs to the serine/threonine kinase family. It is known for its pleiotropic role in cellular processes such as transcription, translation, cell cycle progression, cell proliferation, DNA damage response and maintenance of genome stability. CDK12 forms an active complex with its binding partner Cyclin K and affects the elongation process of transcription by phosphorylating serine-2 at the C-terminal domain of RNA polymerase II. Previous studies have shown that CDK12 plays a role in blastocyst implantation, deletion of CDK12 in a mouse embryo resulted in embryo lethality, but to my knowledge the function of CDK12 in the oocyte has not been investigated. Our main objective was to create a viable mouse model with conditional knockout of CDK12 using Cre-recombinase expressed under the oocyte specific Zona pellucida-3 promoter to study the...

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