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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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Development and dynamics of the palatal and pharyngeal dentition in sterlet
Novotná, Štěpánka ; Soukup, Vladimír (advisor) ; Oralová, Veronika (referee)
Dentition is a key vertebrate innovation showing not only great morphological diversity, but also different maintenance or replacement of functional teeth. Most extant vertebrates replace their dentition through addition of new teeth from deeply invaginated epithelium, i.e. the successional dental lamina, due to presence of dental stem cells. However, in some early branching lineages of ray-finned fishes (Actinopterygii), new tooth germs arise from the adjacent superficial epithelium without the presence of the successional dental lamina. Whether the two types of dental development in vertebrates are equivalent and whether comparable dental stem cells play role in tooth replacement is currently not satisfactorily evaluated. This Master thesis aims at describing the development of palatal and pharyngeal dentition of a member of an early branching lineage of ray-finned fishes, the sterlet sturgeon (Acipenser ruthenus). The sterlet dentition is fairly dynamic. The teeth are replaced without the successional dental lamina, however, this replacement shows characteristics similar to those described in vertebrates with the successional dental lamina. A marker of dental stem/progenitor cells, Sox2, is localized in the outer dental epithelium of the predecessor tooth in the vicinity of the adjacent taste...
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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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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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