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Method of Lagrange multipliers in Calculus of Variations
Borák, Vojtěch ; Černý, Robert (advisor) ; Hencl, Stanislav (referee)
Tato práce řeší několik základních příkladů z variačního počtu a demonstruje prospěšnost zamyšlení se a případné pozměnění úlohy bez snížení dimenze za přítomnosti vazeb. Všechny úlohy jsou řešeny metodou Lagrangeových multipli- kátorů. Především v konečné dimenzi demonstruje hypotézu autora ohledně ne- snižování dimenze problému klasifikace definitnosti diferenciální formy druhých derivací a ukazuje jednak příklad, ve kterém je autorův nápad prospěšný, i pří- klad, kde svádí na scestí. 1
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Early tooth development of Tabby mice
Smrčková, Lucie ; Peterková, Renata (advisor) ; Černý, Robert (referee)
The developing mouse dentition is a very useful tool to study molecular regulation of odontogenesis and also organogenesis. The embryonic mouse dentition comprises developing functional tooth primordia as well as rudimentary tooth primordia. These rudiments arrest their growth during development and either degenerate or become a part of a functional tooth. Mice with gene defects also allow elucidation of a function of genes, their products and signalling pathways. The protein ectodysplasin is essential for development of ectodermal derivatives - skin, hair, glands and teeth. The Tabby mice have a mutation in the Eda gene, which encodes the protein ectodysplasin, and they display a number of dentition anomalies. Early development of the lower jaw dentition in Tabby embryos has been already morphologically described. As a prerequisite for understanding regulatory mechanisms of odontogenesis in Tabby mice, it is also necessary to map the spatiotemporal dynamics of signalling centres that express Shh in both the rudimentary and functional tooth primordia. The aim of this thesis was to compare the signalling centres based on the Shh expression and its spatiotemporal dynamics in the lower jaw of Tabby and WT mouse embryos. Then the Shh data were correlated with known morphological data to clarify the...
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Embryogenesis and early ontogenesis of basal versus derived groups of the Ray-finned fishes (Actinopterygii)
Truhlářová, Veronika ; Černý, Robert (advisor) ; Krylov, Vladimír (referee)
Almost 30 thousand species of the ray-finned fishes, which exist in the world today, represent approximately one half of all known vertebrates. The ray-finned fishes are divided into four distinct groups: bichirs, chondrosteans, neopterygians and teleost fishes. These groups differ significantly in their mode of embryogenesis, however, particular details are known only from few model species like danio or medaka, which all belong to the most diversified actinopterygian group, the teleost fishes. In this thesis, I summarize the current knowledge and compare the patterns of embryogenesis of all four groups of ray-finned fishes. Interestingly, their patterns of early ontogenesis are very dissimilar, such as bichirs and sturgeons undergo holoblastic cleavage of the whole egg, similar to amphibians, whereas teleost fishes evolved strictly meroblastic cleavage of the cytoplasm accumulated on the animal pole of yolk mass, which has profound effects on their further development. The meroblastic cleavage, which is described in details in zebrafish, serves as a template for studying early ontogenesis of all other teleost fishes comprising nearly 27 thousand species. The meroblastic cleavage remained preserved in all teleosts, aside from the fact that these fishes have developed many alternative reproductive...
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Migration and possible skeletogenesis of the trunk neural crest cells in basal fishes
Suchánek, Tomáš ; Černý, Robert (advisor) ; Machoň, Ondřej (referee)
The neural crest is a vertebrate-specific embryonic cell population emerging during neuru- lation in a neuroectoderm. Its cells are highly migratory and differentiate into a wide scale of cell types and tissues ranging from skeletal tissues through pigment cells to neurons and endocrine gland. The neural crest research had been focused on a cranial subpopulation for a long time probably due its apparent skeletogenic activity rather than in the trunk. In this diploma thesis and for a first time I present a data about trunk neural crest cells of basal fishes, Senegal bichir (Polypterus senegalus), sterlet (Acipenser ruthenus) and tropical gar (Atractosteus tropicus). It contains a data about spatio-temporal emergence of trunk neural crest cells of basal fishes, their site of delamination from neuroectoderm, pathways of migration, link between their migration and somite development, segmen- tation during ventro-medial migration and their early diferentiation. Herein I also bring out as first an insight on the trunk neural crest derivatives of the Senegal bichir from in vivo staining experiments using CM-DiI. Key words: trunk neural crest, migratory pathways, exoskeleton, basal ray-finned fishes
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The role of neural crest cells in development of the head and the heart
Matějček, Miroslav ; Machoň, Ondřej (advisor) ; Černý, Robert (referee)
Neural crest (NC) is a structure arising from the neural plate borders during the the process of neurulation. From there neural crest cells migrate and differentiate into broad types of cells and tissues almost all over the body. These cells contributes on the building of skull, jaws and many other structures. The aim of this thesis is to summarize recent findings about neural crest cells and their impact during the development of head and heart, their migration and differentiation in these part of the body with a special aim to gene regulatory network and signals from surrounding cells. Study of these cells is key for elucidating genetic mutations or cancer.
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Early craniofacial and dental morphogenesis in bichir, P. senegalus
Kráľovič, Martin ; Černý, Robert (advisor)
Polypterid fishes are considered the basal-most group of extant actinopterygians and thus may serve as a direct link for understanding the evolution of the first bony fishes. Their embryonic and larval material, however, is extremely scarce what makes it difficult to study their developmental patterns and processes. This work of mine is based on several successful breedings of the bichir Polypterus senegalus that allowed me to analyse development of some 70 specimens at key developmental stages. I have focused my attention to the early morphogenesis of teeth and dentition on several locations within a developmental context of oropharyngeal cavity. Oropharyngeal cavity develops quite differently when compared to other vertebrate species: it arises by means of a schizocoelic- like split of epithelial layers and, moreover, the earliest mouth cavity seems to be strongly constrained by the presence of cement (attachment) glands. Mouth opening proceeds by development of new, enigmatic structures that I have entitled the epithelial bridges (Kralovic et al., 2009) and that might represent the ectoderm-endoderm border often judged to be essential for tooth initiation and patterning. I have described a pronounced delay in initiation of pharyngeal teeth when compared to the oral teeth, probably as a direct...
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Comparative analyses of cranial skeletogenesis and odontogenesis in basal Ray-finned fishes
Pospíšilová, Anna ; Černý, Robert (advisor) ; Přikryl, Tomáš (referee) ; Buchtová, Marcela (referee)
Skeletal (cartilaginous, bony, and dental) tissues undoubtedly exemplify the key innovation of vertebrates. Among all recent vertebrates, the most numerous and successful lineage is represented by the Ray-finned fishes that, accordingly, exhibit amazing variety of skeletal architectures and phenotypic adaptations. In order to depict fundamental principles of fish cranial skeletogenesis the developmental formation of skeletal architectures was described, compared and analyzed using members of early branching fish lineages, that exemplify very different strategies of skeletogenesis. While the Senegal bichirs and the Tropical gars are heavily armored forms with massive exoskeleton and hyperossified dental structures covering the whole oropharyngeal region, the European sterlets, on the contrary, possess mostly cartilaginous skeleton and reduce their dental structures during early development. Whole analysis is underpinned by the Northen pike, teleostean species with lightened skeletal architecture with comparable number of cranial elements. The present study represents the first complex comparative analysis of their skeletogenesis and odontogenesis. This allowed to define developmental strategies founding different lineage-specific skeletal architecture of vertebrates. Comparative description of...
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