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Geographical variation of localisation in vertebrates
Cinerová, Michaela ; Petrusková, Tereza (advisor) ; Turčoková, Lucia (referee)
Sound expressing is common for a big amount of animal species, mostly when communicating with individuals of their own or other species. Acoustic communication can be used especially in situations or in the environment where an individual does not see a signal receiver well (confusing environment, at night or long distance). It's well-known that the individual species have their own characteristic acoustic expressions. However, these can differ also within the species itself, either in time or in space. This study is concerned just with variability of inter-species vocal communication of all vertebrates in space. Its purpose is to map at which animal species vocalization vary in space. Furthermore, it deals with searching for causes of origin of this variability, such as genetic differences among particular groups of populations, environmental and learning effects etc. within various animal species. In the last part, it tries to answer the question whether the spatial variability of acoustic signals could influence separation of new species and thus have evolutionary consequences.
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Regeneration of heart muscle in vertebrates
Bergelová, Barbora ; Krylov, Vladimír (advisor) ; Mašek, Jan (referee)
Fish model organisms such a Danio rerio have the ability to regenerate heart muscle during its whole lifespan. Compared to Danio rerio, the ability of heart regeneration differs in amphibians. While the newt has the ability to regenerate its heart tissue throughout its whole life, the Xenopus leavis loses its power when it goes through metamorphosis. The regenerative ability varies not only between genera but also between species. For example compared to Xenopus leavis, Xenopus tropicalis has the ability to regenerate its heart tissue even in adulthood. Mammals have a very limited ability to regenerate their heart muscle. We can observe the ability to regenerate heart after injury in mice and humans for a very limited time of a few days after birth. In adulhood the heart is healed via rich collagen scar. It is vital that signaling pathways in highly regenerative model organisms are intensively studied, so that the knowledge gained may help us in the treatment of heart injuries in humans. Key words: regeneration, heart muscle, repair, zebrafish, mammals, amphibians, heart development, vertebrates
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Antero-posterior polarization of body appendages in vertebrates
Smlsal, Dan ; Soukup, Vladimír (advisor) ; Krylov, Vladimír (referee)
Body appendages of vertebrates are structures developing during embryonal stages through lateral outgrowth from main body axis. Despite their different composition and high diversity, all these structures are organised along three main axes. Antero-posterior polarization is the most significant in body appendage differentiation. These polarized differentiation changes are best understood in the limbs, where they are controlled by the organizing centre named zone of polarizing activity (ZPA). This centre interacts with another centre named apical ectodermal ridge (AER), which mainly governs limb outgrowth laterally from the body axis. ZPA produces Sonic hedgehog (Shh), along with other signalling molecules participating in the polarization. Shh is a key part of highly conserved signalling pathway common to polarized structures and is influenced by retinoic acid (RA), which plays role in the ZPA creation. ZPA activity stimulates secretion of fibroblast growth factors (Fgf) and bone morphogenic proteins (Bmp). All these signalling pathways ensure correct differentiation of appendages through interaction and concentration-dependent mechanisms. The goal of this thesis is to introduce the mechanisms of polarization in other appendages, such as external genitalia and branchial arch derivates to the reader,...
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Regeneration of heart muscle in vertebrates
Bergelová, Barbora ; Krylov, Vladimír (advisor) ; Mašek, Jan (referee)
The model organisms like for example the fish Danio rerio has the ability to regenerate heart muscle during its whole lifespan. Compared to Danio rerio, the ability of heart regeneration differs in amphibians. While the newt has the ability to regenerate its heart tissue throughout its whole life, the Xenopus leavis loses its power when it goes through metamorphosis. The regenerative ability does not only differ between salamanders and claws. We can observe some differences between regeneration of Xenopus tropicalis and Xenopus leavis too. Compared to Xenopus leavis, Xenopus tropicalis has the ability to regenerate its heart tissue even in adulthood. Mammals have a very limited ability to regenerate their heart muscle. We can observe the ability to reverse heart damage in mice and humans for a very limited time of a few days after they are born. In adulhood they repair the heart muscle and the rich collagen scar is formed. It is vital that signaling pathways in regeneration of model organisms is researched further, so that the knowledge gained may help us in the treatment of heart injuries in humans. Key words: regeneration, heart muscle, repair, zebrafish, mammals, amphibians, heart development, vertebrates
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Comparative development & evolution of adenohypophysis in vertebrates
Brezarová, Dominika ; Černý, Robert (advisor) ; Kozmikova, Iryna (referee)
Adenohypophysis is very important gland in vertebrate head. In general adenohypophysal development is described together with formation of the primary mouth. Adenohypophyseal placode migrates together with stomodeal placode in ventral direction. Stomodeal placode starts to invaginate and from oral ectoderm adenohyphyseal placode invaginates to form Rathke's pouch. Pouch is then separated from mouth and migrates towards the brain to make adult hypohyseal gland. Origin of adenohypophysis is therefore in oral ectoderm, but in some vertebrates species is this development little different and adenohypophysis can even be endodermal. In some vertebrate groups, like amphibians or fishes there's no sign of Rathke's pouch, thus early migrations of adenohypophyseal placode can be different. These differences are there maybe because these groups don't have shallow invagination of stomodeum like other vertebrates. There are some homological structures in other chordate groups, for example Hatshek's pit in amphioxus or neural gland in tunicates, these structures has, in contrast with vertebrates, endodermal origin. Key words: adenohypohysis, placodes, primary mouth, craniofacial development, Rathke's pouch, vertebrates
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Shared mechanisms of development of vertebrate body appendages
Vintr, Jan ; Soukup, Vladimír (advisor) ; Krylov, Vladimír (referee)
Vertebrate body appendages include a number of structures such as limbs, paired and median fins, the tail bud, the cloacal region, barbels or pharyngeal arch derivatives. Despite differences in form and function, these appendages share a number of developmental genetic mechanisms. Development of these structures is chiefly regulated by Fgf, Shh, Wnt, Tgf-β and retinoic acid signalling pathways, activity of transcription factors such as Hox or Tbx along with cis-regulatory elements controlling the genes in which these factors are encoded. A recurring feature shared by some of the herein discussed anatomical structures is a transient epithelial ridge whose activity influences production and proliferation of the adjacent mesenchyme. Some are also instructed by a signalling centre, which confers asymmetry to the structure. In this text, the various appendages are compared on the basis of their development in relation to tetrapod limbs and theories evaluating the emergence of vertebrate paired appendages. The fin fold theory and archipterygial theory are discussed in the light of recent data provided by evolutionary developmental biology. All together, this thesis evaluates shared and derived characteristics of vertebrate body appendages with the aim to provide a basis for the upcoming work on the role...
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The embryonic development of the pharyngeal region in vertebrates
Píchová, Lenka ; Černý, Robert (advisor) ; Minařík, Martin (referee)
The fully-formed pharynx is for adult vertebrates indeed a vital structure. The pharynx provides two main functions - dealing with food and breathing. During embryonic development, pharynx is visible like a series of bulges on the lateral surface of the head. Embryonic development of the pharyngeal region starts with evagination of the endoderm to form the pouches, opposit to that the ectoderm invaginates to form the ectodermal clefts. Pharyngeal arches are formed after fusion of these epithelial layers, and pharynx is thus bordered by ectoderm from the inner, and endoderm from the outer side. Each pharyngeal arch consists of mesenchymal core of mesodermal and neural crest derived cells. All vertebrates develop through the so called phylotypic stage, being represented by the - pharyngula with the present pharyngeal arches. Accordingly, it was generally believed that development of the pharyngeal region is rather conservative in all vertebrates. My comparative analysis of pharyngeal development in different vertebrates species reveals that - only early embryonic formation of pharyngeal arches seems conserved, however, that later in development pharyngeal arches form various and diverse derivatives. Key words: Vertebrates, ectodermal fleft, endodermal pouch, pharyngeal arches, neural crest
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Modulation of the pharyngeal dentition during the vertebrate evolution
Novotná, Štěpánka ; Soukup, Vladimír (advisor) ; Zahradníček, Oldřich (referee)
Teeth represent a key evolutionary novelty of vertebrates. The dentition of the majority of extant vertebrates is present in the oral cavity associated with jaws and palate and/or in the pharyngeal cavity asscociated with the last pharyngeal arch. The ancestral state of the vertebrate dentition is considered to be presence of teeth through the whole oropharyngeal cavity. This state is however preserved only in few members of extant osteichthyans (for example bichir and latimeria). The other vertebrates gradually lost the pharyngeal dentition. The basal groups of actinopterygians meet the conditions of preservation of the ancestral states and are thus relevant for understanding the initial state in the evolution of vertebrate dentitions. On the other hand, some derived actinopterygian lineages contain members with the most specialized pharyngeal dentitions. This bachelor thesis concentrates on the description of pharyngeal dentitions accross vertebrates and focuses on members of basal actinopterygian lineages (bichir, sturgeon and gar), which from the point of view of dental evolution represent crutial, although neglected animals. Detailed description of pharyngeal dentitions of these animals will form a basis for the upcoming Diploma project. Key words: teeth, dentition, evolution, vertebrates, pharynx
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Dental stem cells during development of vertebrate dentitions
Pešanová, Věra ; Soukup, Vladimír (advisor) ; Hovořáková, Mária (referee)
Vertebrate dentition is a dynamic structure, which continuously renews its elements, the teeth. Continuous tooth renewal is enabled thanks to the presence of epithelial and mesenchymal dental stem cells. Epithelial stem cells are located in the dental lamina, which, together with the adjacent mesenchyme, takes part in regulation of the stem cells through a complicated signalling network. This network is responsible for the positioning, correct amount, inactivity, proliferation and differention of the stem cells. Vertebrate dentitions are morphologically diverse. However, their development is, to a certain extent, controlled by shared evolutionarily conserved mollecular mechanisms. For example, epithelial stem cells of all vertebrate groups examined so far express the transcription factor Sox2 and are shown to be regulated by signalling pathways, such as Wnt/β-catenin, Shh, Fgf and Bmp. Due to the rich diversity in dental lamina morphologies, the locations of presumptive stem cells correspondingly differ among vertebrates. This thesis summarizes current knowledge on dental stem cells in each lineage to identify shared and derived aspects of vertebrate dentitions.
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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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