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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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Comparative development of scales and surfaces of fishes
Uherková, Michaela ; Černý, Robert (advisor) ; Vaškaninová, Valéria (referee)
1 Abstract The body surfaces of cartilaginous fishes (Chondrichthyes) and bony fishes (Osteichthyes) are composed of scales, with individual scale types differing in their morphological description, stratification, morphogenetic development and representation in each group. In fossil species, we encounter hard bony shells or plates, which gradually change during evolution to flexible scales of the elasmoid type, these are found in contemporaneous representatives of the bony fish group (Teleostei). Recent scale types found on the surface of present-day fish-like vertebrates include modified cosmoid scales, ganoid scales, placoid scales and elasmoid scales. Odontodes, which include placoid scales, ganoid scales, vertebrate oral teeth and pharyngeal teeth, are a key component in the evolutionary development of all these body surfaces. Odontodes form the basic structural unit of all dermo-skeletal structures and, from an evolutionary point of view, have evolved into the scales and oral teeth of vertebrates. Because of the interesting correlation between teeth and scales, a separate chapter of the literature review will be devoted to theories of the origin of oral teeth. The present bachelor's thesis discusses the evolutionary development of scales of cartilaginous fishes and bony fishes with respect to the...
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Comparative development & evolution of adenohypophysis in basal fishes
Brezarová, Dominika ; Černý, Robert (advisor) ; Buchtová, Marcela (referee)
The pituitary is a master endocrine gland in the vertebrate head with many crucial roles in producing hormones and controlling secretion of other glands, and with long-standing controversies on its evolution and embryonic origin. Adenohypophysis (ADH), the front lobe of the pituitary, develops from the rostral placode that extensively migrates under the brain to connect the neurohypophysis, evagination of the ventral hypothalamus. Owing to its ectodermal placodal origin, ADH is commonly understood as a part of the vertebrate specific acquisition of our new head. Recently, however, an endodermal contribution to ADH was revealed in the teleost fish, supporting classic claims of a pre-vertebrate origin of this organ from an ancient chordate pharyngeal structure. In this work, early development of ADH was characterized in three species of basal fishes, bichirs, sturgeons, and gars, representing a possible stem-like pattern of early vertebrate craniogenesis. Interestingly, in all three species, both the early development and later migration of ADH is intimately linked with the pharyngeal domain in the rostral head. In sturgeon embryos, ADH migrates in between the brain and the pharyngeal domain, which further separates ADH from the forming mouth. In bichir embryos, ADH was additionally shown to get...
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Migration and morphogenesis of neural crest cells in the context of craniofacial development of selected ray-finned fishes
Štundl, Jan ; Černý, Robert (advisor) ; Buchtová, Marcela (referee) ; Machoň, Ondřej (referee)
Neural crest (NC) cells play a crucial role in vertebrate development and evolution. This cell population contributes to many new cell types such as chondrocytes and osteocytes of the head skeleton, neurons, pigment cells, cardiomyocytes, and many others. As such the neural crest is often considered as the fourth germ layer. This vertebrate-specific cell population emerges during formation of the neural tube. Whereas in the trunk region NC cells migrate as separate cells, cranial neural crest (CNC) cells extensively migrate in three discrete streams forming most of the head mesenchyme. In all vertebrates, CNC stereotypically follows the tripartite pattern of migration along the anteroposterior axis so that the most anterior (trigeminal) stream emerges first, followed by the hyoid and branchial CNC streams. In this work, I have studied representatives of all three lineages of non-teleost fishes (bichir, sturgeon, and gar) and also one species from the crown group of ray-finned fishes, the pike. The main question I addressed in my project was whether the CNC cells stereotypically follow a tripartite pattern of migration along the anteroposterior axis as is seen throughout vertebrates. Surprisingly, I found several alterations in the emergence of CNC cells and their migratory pattern in the studied...
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Developmental origin of cartilage skull elements in axolotl
Kloučková, Lenka ; Černý, Robert (advisor) ; Roček, Zbyněk (referee)
Despite the fact that some aspects of single studies differ, there's a generally accepted view that the whole cartilaginous viscerocranium of vertebrates is neural crest derived. By the series of isotopic transplantation experiments of presumptive neural crest on the model organism Ambystoma mexicanum I partly specify this oppinion and prove that the most ventro-caudal cartilage, the second basibranchial, is of a different origin. Furher I mention the level of the presumptive neural crest where the single parts of cartilaginous viscerocranium arise from. Moreover there is one element, the first basibranchial, which has double origin. I discuss also some other neural crest derivatives such as head and outer gills mesenchyme, the trabeculae cranii, part of the cartilaginous otic capsule or the connective tissue in the head. I have performed 179 transplantations between transgenic and normal axolotl embryos. My final analysis is composed of 65 embryos of stage 40 - 42 and 7 larvae of lenght of 15 - 17 mm.
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Elementary methods for solution to difference equations
Sadil, Antonín ; Černý, Robert (advisor) ; Stará, Jana (referee)
Nazev prace: Eleinentanii melody fcseni diferencnieh rovnic Autor: Antonin Sadil Katedra (ustav): Katedra matematieke analyzy Vcdonci bakalafske prace: RNDr. Robert Corny,Ph.D. e-mail vedouciho: rc.erny^karlm.mff.eimi.e/ Abstrakl: Tato prace pojednava o metodaeh feseni linearnich diferencnieli rovnic. Zamefuje se na. vlastnosti feseni homogomn'ch rovnic a nalezeni fundamentalniho systemu pro jodnodnoho, nasobne i komplexni kofeny charakteristickeho polynomu. U nchomogcnnich rovnic sc pak zamefuje pfedevsim na inctody pro nalezeni partiku- larniho feseni. Dale so kratco zal">yva fosenim linoarni diferencni rovnice prvniho fadu s nekonstaiiUiimi kooficienty a v zaveru popisuje uietody feseni sonstav liiioarnich diforencnich rovnic prvniho radii. Cola toorie jo poistavona na dnkazoch a pro lopsi pochopeni je proloiona nekolika ilustrativnimi pfiklady. Klicova slova: homogenni rovnice, nohoniogonni rovnice, fundainentalni system Title: Elementary methods for solution to difference equations Author: Antonin Sadil Department: Department of Mathematical Analysis Supervisor: RNDr. Robert Ceriiy,Ph.D. Supervisor's e-mail address: rrerny^karlin.mfT.cuni.cz Abstract: This work presents aboul methods for solution to difference equations, ft focus on characteristics of solutions of the homogeneous equations and finding...
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Mechanisms of the cell migration in the early embryonic development of vertebrates
Kováčiková, Petra ; Krylov, Vladimír (advisor) ; Černý, Robert (referee)
Cell migration, usually seen as a relatively well understood phenomenon, is involved in many aspects of multicellular organisms. While given a major attention due to its part in physiological processes, such as immune response, wound-healing and regeneration, or pathologies like progression of metastatic cancers, its key role in the body plan formation is far less understood and often overlooked. During a process called gastrulation, precursors of three germ layers - superficial ectoderm, inner endoderm and medial mesoderm - are arranged according to their fate, generating a three-layered embryo, a hallmark of triblastic vertebrates. The onset of this highly coordinated step of early embryonic development is accompanied by fine-tuned cell migration, which needs to be downregulated in adults in order to maintain a homeostasis. The cells forming gastrulating embryos collectively undergo a set of behaviors termed morphogenetic movements whose features - partially comparable to ones observed on cells migrating in culture - are shared among vertebrate species, providing valuable insights into "hidden homology" and phylogenetic relationships. Research focusing on regulation and mechanisms of morphogenesis is mostly conducted using Xenopus laevis as a model organism, extrapolating results to higher...
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Ontogeny, evolution & homology of cement glands and attachment organs in lower vertebrates
Minařík, Martin ; Černý, Robert (advisor) ; Ráb, Petr (referee) ; Buchtová, Marcela (referee)
Aquatic larvae of many vertebrate lineages develop specialized, cranially located cement or attachment glands which allow them to remain attached to a substrate by means of polysaccharide secretion. The larvae can thus remain still and safe in well-oxygenated water out of reach of any predators until the digestive and locomotory apparatus fully develops. Xenopus cement gland is the most thoroughly studied example of this type of glands, since it was used as a model for the anteriormost patterning of the developing head. Based on shared expression patterns of key transcription factors and a similar ectodermal origin it has been repeatedly suggested that Xenopus cement gland is homologous to adhesive organs of teleosts and adhesive papillae of ascidians. The lack of comprehensive knowledge on this type of glands in other lineages however rendered any considerations of homology among such a distant lineages rather inconclusive. In the present work I have focused on a detailed study of the cement glands and other corresponding structures in three representatives of basal actinopterygian lineages: Senegal bichir (Polypterus senegalus), sterlet (Acipenser ruthenus), and tropical gar (Atractosteus tropicus). Using a combination of in vivo fate-mapping approaches with a Micro-CT imaging of cranial endoderm...
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Functional equations
Konopecký, František ; Hencl, Stanislav (advisor) ; Černý, Robert (referee)
Nazev pracc: Funkcionalni rovnice Autor: Frantisck Konopccky Katedra (ustav): Katcdra matcmaticke analyzy Vedouci bakalafske pracc: RNDr. Stanislav Hcncl, Ph.D. e-mail vedouciho: hencK(.i)karlni.mrT.cmri.cz Abstrakt: V pfcdlozcnc praci ye zabyvame mctodami fcscni funkcionalnich rovnic, triky, kterc fescni usnadnuji, vlastnostmi funkci, kterc pfi fescni pomahaji a myslenkovymi po- stupy pfi samotnem fescni. Nejprve za/Jvame pojem a praci s funkcionalni rovnici. Pote vysvetlnjeme dvc hlavni inetody - Substitucni-A Cauchyova. Naslcduji diilczite vlastnosti fnnkci a po nich ka]>itola o castych chybach pfi foscni. Ko konci se venujcme Cauchyove rovnici z vice stran a naslednje nckolik fesenych i nofcsenych pfikladu. Klicova slova: Fnnkcc, funkcionalni rovnice. Title: Functional Equations Author: Frantisek Konopccky Department; Department of Mathematical Analysis Supervisor: RNDr. Stanislav Hcncl, Ph.D. Supervisor's e-mail address: hencK(fikarlin.mfi.cnui.cz Abstract: In this thesis we study methods of solving strategies of functional equations, tricks, which make solving easier, special function properties, that help in solution and also ideas in solution itself. Firstly we get closer to term functional equation and show how to work with it. Then we explain two main methods Substitution method and Cauchy's...
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