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New possibilities to distinguish monozygotic twins
Letková, Kristína ; Kulichová, Iva (advisor) ; Priehodová, Edita (referee)
The necessity of distinguishing monozygotic twins from a genetic point of view is important not only for determining paternity, when it is decided which of two identical twins is the father, but also, for example, for criminal cases, where it is necessary to identify the perpetrator who is one of the monozygotic twins. In addition to analyzing and evaluating molecular biological methods, the work also deals with monozygotic twins themselves, their emergence and the causes of their emergence. The topic affects both forensic genetics and medical fields.
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Root - shoot junction (collet) development
Hermann, Jiří ; Žárský, Viktor (advisor) ; Tylová, Edita (referee)
Although the root-shoot junction (collet) of adult plants is a well-identifiable part of the plant body, its development has, surprisingly till now, escaped serious research attention. The junction is a key region in the life of plants, as it connects two contrasting plant life environments and involves important changes in developmental programs - underground vs aboveground. The junction in angiosperms is first established during the embryogenesis phase of development in the form of the broad embryonic root- hypocotyl transition region, and it continues to develop further after seed germination during the individual's growth. The most important organ in this process is the hypocotyl, which exhibits considerable developmental plasticity, allowing extraordinary elongation in etiolated dark growth but also initiating formation of adventitious roots upon the deetiolation. During each stage of the junction's development, auxin signalling and polar auxin transport play a crucial role. Most of the research focuses on the development of the junction in the model organism Arabidopsis thaliana. The significance of the phylogenetic origin of the junction is also discussed from the perspective of the evolutionary origin of roots vs shoots and embryos evolution. This work aims to provide an overview of the...
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Mapping of the cell population expressing Sonic hedgehog during the embryonic development of heart
Břežná, Veronika ; Hovořáková, Mária (advisor) ; Šaňková, Barbora (referee)
Sonic hedgehog is one of three members of the Hedgehog family, whose signaling pathway plays a crucial role in controlling the development of vertebrates. Sonic hedgehog has an important role in organizing the developmental processes of majority of organ systems. Interestingly, its direct expression or a contribution of cell lineages expressing this signaling molecule in the myocardium has never been described. The aim of this work was to try to detect the cells that expressed Sonic hedgehog directly in the heart tissue with a focus on the myocardium. We monitored these cells from embryonic day 10.5 to 16.5 and then postnatally. We also evaluated current Sonic hedgehog expression in cardiac tissue from embryonic day 12.5 to embryonic day 15.5. We used the CreLoxP system, X-gal staining, fluorescence and confocal microscopy to detect cell lines expressing Sonic hedgehog. We also assessed the presence of cells that expressed Sonic hedgehog in the developping heart in the past using immunohistochemistry. According to our results, the presence of a descendant cell lineage expressing Sonic hedgehog in the past was demonstrated prenatally and postnatally in the mouse myocardium. The performed analysis shows that these cells can be detected in cardiac tissue from embryonic day 10.5 till the postnatal...
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Parent-of-origin contributions to gene expression during sexual plant reproduction
Pitoňak, Oliver ; Honys, David (advisor) ; Fischer, Lukáš (referee)
Sexual reproduction in flowering plants is fundamental to seed formation. After fertilization, the embryo is enclosed and develops in a seed together with a triploid tissue - the endosperm. In animals, early embryogenesis is well-known to be controlled by maternal RNA and proteins deposited in the ovule before fertilization. Even after the activation of zygotic genome, paternal and maternal genome do not play interchangeable roles. A few genes affecting embryo growth and development are transcribed either from maternally or paternally inherited alleles only. Such genes are example of the well-known phenomenon of gene imprinting. In plants, imprinting is well documented in the endosperm. The role of parent-of-origin contributions to gene expression has been studied less extensively in embryo. The aim of this work is to critically assess current knowledge of parent-of-origin contributions to embryo development in different plant species.
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The prechordal plate during embryogenesis of the vertebrate head
Marková, Kristýna ; Černý, Robert (advisor) ; Soukup, Vladimír (referee)
The prechordal plate is generally described as a population of axial mesendodermal cells that is formed during early embryonic development, in the rostral- most area of the vertebrate head. The population of the prechordal plate cells is specific for vertebrate, and evolution of the vertebrate head was one of the key steps during vertebrate evolution. During vertebrate embryogenesis, the prechordal plate cells are pushed by the growth of the forebrain, until only some small population remains in front of the notochord, which later differentiate into mesodermal cells. The precise morphogenesis of this prechordal mesoderm, differs across vertebrates, but in most vertebrates produces a pair of head cavities, which are called premandibular. Within the organogenesis of vertebrates, extrinsic eye muscles are formed from these mesodermal cells and cavities. The prechordal plate, however is also referred to as one of the important centers that control the formation of the vertebrate head during early embryogenesis, since its removal or inhibition of important signals caused various disorders and embryonic dead. This thesis aims to summarize the information on the formation and function of the prechordal plate cells during vertebrate embryogenesis. Key words: prechordal plate; prechordal mesoderm; head...
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Nuclear architecture and gene expression in Caenorhabditis elegans
Bolková, Jitka ; Lanctôt, Christian (advisor) ; Macůrková, Marie (referee) ; Kostrouch, Zdeněk (referee)
Nuclear architecture and gene expression in Caenorhabditis elegans Mgr. Jitka Bolková ABSTRACT The parental genomes are initially separated in each pronucleus after fertilization. During the first mitosis this spatial distribution is being disintegrated. In my thesis we used green-to-red phoroconversion of Dendra2-H2B-labeled pronuclei to distinguish maternal and paternal chromatin domains and to track their distribution in space in living Caenorhabditis elegans embryos starting shortly after fertilization. Both of the parental chromatin domains within the nucleus are separated in the zygote and at the 2-cell stage. Intermingling occurs first after chromatin decondensation at the beginning of the cell cycle at the 4-cell stage. To our knowledge, we report to the first live observation of the separation and subsequent mixing of parental chromatin during embryogenesis. Following of the photoconverted chromatin also allowed us to detect a reproducible 180ř rotation of the nuclei during cytokinesis of the zygote. Tracking of fluorescently-labelled P granules and polar bodies showed that the entire embryo rotates during the first cell division. In the second part of the thesis we used the C. elegans model to investigate relationship between nuclear architecture and gene expression. We focused on localization of...
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The embryonic formation of the primary mouth in vertebrates
Psutková, Viktorie ; Černý, Robert (advisor) ; Soukup, Vladimír (referee)
The primary mouth develops during early embryogenesis at the anterior end of the forming head and it is created from the ectoderm and the endoderm that directly juxtapose. The primary mouth is the first connection of the digestive system with the outside, which is undoubtedly a crucial step for further development of an organism. In most vertebrates, the primary mouth is getting opened by perforation of a thin septum, the oral membrane. The oral membrane is formed from the ectoderm and the endoderm, when the ectoderm pushes against endoderm. Surprisingly, developmental formation of the primary mouth is not identical in all vertebrates and we can commonly recognize three main developmental modes. In the most vertebrates clades, the primary mouth forms via the so called stomodeal invagination, which is often exemplified in the frog Xenopus leavis. The primary mouth of salamanders and lungfishes forms via the so called stomodeal collar and the primary mouth of teleost fishes forms via the so called stomodeal wedge. Moreover, in the hagfishes, the development of the primary mouth seems similar to the stomodeal invagination, but with some substantial differences in later formation. The particular mode of the primary mouth formation probably depends on the course of embryonic development and spatial...
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Comparison of migration and morphogenesis of neural crest cells in Ray-finned fishes: towards identification of developmental sources of craniofacial diversity
Štundl, Jan ; Černý, Robert (advisor) ; Drobná Krejčí, Eliška (referee)
Extensively migrating population of neural crest cells, which contributes to many tissues and builds up most of craniofacial vertebrate structures, has a crucial role in embryonic development of vertebrate body. The migratory pathways of neural crest cells are thought to be very conserved throughout the vertebrates and cranial neural crest migration is defined by progression of three migratory streams: trigeminal, hyoid and a common branchial stream. In this diploma thesis, migration of cranial neural crest was analysed using embryos of the Senegal bichir (Polypterus senegalus) and of sterlet (Acipenser ruthenus), which represent two basal-most lineages of extant ray-finned fishes. A combination of several techniques was used in both species in order to study cranial neural crest cells from their sites of origin to post- migratory stages and the pattern of migration was compared and discussed in revealed embryonic context. In the Senegal bichir the hyoid neural crest stream was shown to migrate first and it is also the most abundant; this heterochrony shift is apparently related to formation of external gills, which in bichir are situated on the hyoid arch only. In sterlet, neural crest cells migrate in a classic pattern of three progressive streams but their dynamics and patterning is influenced by...
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Embryonic development of the unfertilized silkworm eggs
VRCHOTOVÁ, Markéta
Transgenesis of silkworms has great potential for the development of silk with new properties as well as for the preparation of recombinant proteins for the use in biomedicine. Zabelina et al. (2015a) showed that transgenesis of parthenogenetic silkworms facilitates the selection and maintenance of transgenic homozygotes with stabile transgene insertions. However, the efficiency of transgenesis was less than 2 % compared to 60 % in the standard, non-parthenogenetic silkworms. The purpose of the present research was to explore the cause of this difference. Since transgenesis is normally performed at 25 °C but in the parthenogenetic silkworms at 15 °C (3 days incubation at this temperature is part of the protocol for the induction of parthenogenetic development), we assumed that the eggs incubated at 15 °C might have been injected with the DNA construct at unsuitable time. The work was therefore focused on the rate of embryogenesis at 15 °C in the eggs treated in different ways. Intensive cleavage of the control eggs (strain K23) was observed at 12 h after oviposition at 25 °C and between 24 and 36 h at 15 °C. The transgenesis of parthenogenetic silkworms is also complicated by the embryonic diapause. In the current work, diapause was suppressed by implanting PK1 ovaries into the non-parthenogenetic male hosts K23. Parthenogenetic development was activated by the heat shock in the chorionated eggs dissected from the implants. No cleavage was detected at 12 h after the acti-vation and nearly complete blastoderm was found at 48 h. In respect to the course of cleavage at 15 °C, transgene injection 24 h after the activating heat shock can be recommended. The eggs from endogenous ovaries of the K23 females, which also contained the implants of the PK1 ovaries, acquired partial capacity of parthenogenesis. Low rate of embryogenesis was also found in the transgenic clone VTG1. Current results suggest that more research is needed to understand and possibly explore differences in the rate of silkworms exposed to different treatments.
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