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Evolution and function of hidden anti-predator signals
Ziková, Magdaléna ; Exnerová, Alice (advisor) ; Pipek, Pavel (referee)
Hidden anti-predator signals (HAS) are hidden colour patterns in an otherwise cryptic prey; they are revealed upon encountering a predator. HAS include deimatic signals (DS) and flash signals (FS). DS are used when at risk of predation, typically after being discovered by a predator. Their position in the predation sequence (PS) differs by species. DS are often linked with deimatic behaviour, that boosts their efficiency. The use of DS in later stages of the PS occurs more often in defended prey, which may thus speed up predators' avoidance learning. In undefended prey, DS may trigger startle or fear responses, confusion or sensory overload in the predator, thereby pausing or stopping the attack. FS are exposed during the prey's escape, usually early in the PS before a predator detects the prey. This can cause a predator to form a wrong impression of the prey's appearance, making it harder to find. FS can also attract the predator's attention during pursuit, thus decreasing its chance of noticing an evasive manoeuvre. Dynamic FS, in which different colours alternate during movement, can make it hard to estimate the prey's position. The presence of both types of HAS is often linked with prey body size. The efficiency of FS is affected by the flight initiation distance. The efficiency of DS is related to...
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In vitro models for studying Syncytin-1-induced fusion of trophoblast cells
Jech, Lukáš ; Trejbalová, Kateřina (advisor) ; Zíková, Martina (referee)
Trophoblast cell fusion is essential for human placenta development. Apart from initiating blastocyst implantation, syncytialization is critical for optimal nutrient and gas exchange between mother and fo- etus. Multicellular syncytia called syncytiotrophoblast covers the surface of the branched structure of chorionic villi, which is in direct contact with maternal blood. Impairment of the syncytialization process leads to insufficient fetal nutrition and severe pregnancy complications. Syncytia formation is induced by the interaction of the surface glycoprotein of retrovital origin, Syncytin-1, with its receptor. Despite the significance of these processes, the details of cell fusion and trophoblast differentiation remain unk- nown. Furthermore, because of its uniqueness, the human placenta cannot be covered by animal models. As a result, research into human placental development, especially Syncytin-1-induced trophoblast cell fusion, is limited to in vitro trophoblast models. These models include primary trophoblast cell cultures and trophoblast cell lines, which can be obtained by immortalizing cell cultures or extracted from trophoblast tumours. Dedifferentiated trophoblast stem cell cultures were also established. The most recent approach, however, involves the direct reprogramming of dermal...
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Development of the Czech secondary preposition kvůli from a constructional perspective
Čermák, Jan ; Friedová, Mirjam (advisor) ; Králová Zíková, Magdalena (referee)
The aim of this thesis is to map the historical development of the modern Czech secondary preposition kvůli, which denotes causality and is complemented by a dative NP in standard language and by a genitive case in certain dialects of North Moravia. Its development can be traced back to the Old Czech benefactive prepositional phrase (PP) k vóli/k vuoli (literally 'to/toward will'), which was used as an adverbial of reason or goal of the event denoted by the predicate, with respective meanings 'according to sb's will', or 'to sb's satisfaction'. The beneficiary was either expressed by common possessive means inside the PP (e.g., by a genitive noun phrase (NP) or a possessive pronoun), or by an external dative NP, which was syntactically independent of the PP and functioned as a verbal argument. Adopting the approach of Construction Grammar (Fillmore, 1988, 1989; Fried & Östmann, 2004) and drawing on findings from grammaticalization research, historical material spanning the Old Czech, Middle Czech and Modern Czech period is analysed, paying attention to individual contextual features that enabled the changes leading to the modern prepositional use. Through a series of contextually conditioned and interdependent semantic, syntactic, morphosyntactic, and phonological shifts, the expression gradually...
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Methods of isolation of individual subpopulations of neural stem cells
Zelený, Martin ; Zíková, Martina (advisor) ; Vargová, Ingrid (referee)
Stem cells have huge medical potential, but they are not explored enough for the use in medicine yet. Because of that, their further research is important. One group of the stem cells are neural stem cells, which are differentiating into the neural and glial cells in the brain. Neural stem cells are present at the two areas in the adult brain, subventricular zone and subgranular zone of hippocampus. Neural stem cells are not one homogenous population of cells, but rather various subpopulations with different cell expression. In my bachelor thesis I described the methods, which are used in the research of neural stem cell subpopulations. Described methods focused mainly on the isolation and gene expression. Keywords: neural stem cells, neurogenic zones, molecular markers
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Role of Exosomes in the Progression, Diagnosis, and Treatment of Brain Tumors
Vaníková, Lucie ; Zíková, Martina (advisor) ; Lacina, Lukáš (referee)
Recent studies have confirmed the importance of extracellular vesicles, particularly exosomes, in the development of brain tumors. Considerable attention has been paid mainly to the influence of exosomes on biological processes in brain tumors. Exosomes mediate intercellular communication in the tumor microenvironment by transporting biomolecules. Most often they transmit various types of ribonucleic acids, specifically microRNAs, which affect the signalling pathways related to tumour growth in target cells. Thus, exosomes play an important role in tumor cell proliferation and differentiation, metastasis, and tumor resistance to chemotherapy or radiation. Due to their small size, exosomes can cross the blood-brain barrier and thus promote tumor progression. The topic of the bachelor thesis is a summary of the current knowledge on the role of exosomes in brain tumor progression, diagnosis and treatment.
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Evolution of discourse markers in Czech: case study of vždyť
Doischer, Tomáš ; Zíková, Magdalena (advisor) ; Beneš, Martin (referee)
The main goal of this paper is to analyze one specific Czech discourse marker, vždyť, both from the synchronic and diachronic position. In the context of this analysis, some questions of linguistic methodology are discussed. Most of this analysis focused on its semantic properties, which were described using the NSM methodology (Natural Semantic Metalanguage). NSM allows its users to describe the meaning of grammatical words in natural language, thanks to which a researcher can formulate the expression's function without having to use a complicated and obscure terminology. The resulting definition of vždyť is compared to the description found in Czech dictionaries, whose authors, unlike my approach, describe the meaning of vždyť in terms of multiple senses, polysemy. Apart from semantics, a small part of the chapter is dedicated to the description of other properties of vždyť, e. g. phonetics. In the diachronic analysis, a hypothesis is formulated about the emergence of vždyť from the originally temporal marker vždy, explaining it on the basis of conversational implicatures. That is illustrated by some examples of vždy from the earliest available linguistic data from Czech. I then describe the meaning of vždyť in Old Czech, while speculation about its further development is hindered by the lack of adequate...
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Word-level phonetic variability in public speaking
Kodytková, Carmen ; Machač, Pavel (advisor) ; Zíková, Magdalena (referee)
This thesis concentrates on phonetic variability of words in public speaking. In the first part of the thesis, the aim was to summarize the existing knowledge about the characteristics and principles of spontaneous speech, about phonetic features of Czech speech sounds and about factors that may influence type and degree of reduction. Then we summarize the results of older studies done on other languages (esp. on Dutch and German) and outline a possible application of results from word variability analyses. In the second part of this thesis we look at five Czech words - protože, prostě, myslím, samozřejmě and určitě. We set several groups of variants according to the degree of reduction for each word, we examine stability of their phonetic features and survey whether position (initial, medial, final and I = F) in intonation unit and/or speed of pronunciation of the chosen word has an influence on degree of reduction. Five to eight hierarchical groups of variants were set for each chosen word. Stability of phonetic features in four types of speech sounds (vowels, nasals, unvoiced plosives and unvoiced sibilants) is in line with the existing observations (e.g. Machač, 2004). Speed of pronunciation of the word had an influence on the degree of reduction in words protože, prostě, samozřejmě and určitě,...
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Grammaticalization potentiel of the anaphoric ten in spoken narative discourse
Zíková, Magdalena ; Friedová, Mirjam (advisor) ; Nedolužko, Anna (referee) ; Berger, Tilman (referee)
In my Ph.D. thesis, I examine the use of referential devices in spoken narrative discourse with predominant anaphoric reference. Special attention is paid to the relationship between two competing forms: lexical phrases containing the lexeme ten (ten-MARKED NPs) and lexical phrases not containing it (UNMARKED NPs) in repeated mentions. A primary aim of the work is (i) to identify factors favouring the use of ten-marked NPs at the expense of unmarked NPs and (ii) to explore the possibility of the lexeme ten grammaticalizing from its anaphoric use. Theoretically and methodologically I benefit mostly from the conception of discourse anaphora and the theory of grammaticalization. The referential devices are systematically explored in terms of their distribution into different classes according to a set of parameters and their values. These parameters reflect the conceptual (animacy), grammatical (syntactic function, type of clause etc.) as well as discourse characteristics of the forms and their referents (informational status of the NP in the clause, activation and persistence of the referent, etc.). The data consist of 45 short narratives produced by 15 speakers. The speakers' task was to retell three short silent-movie sketches which they had seen immediately before the recording. The design of the...
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Cell therapies designed to restore radiation-induced brain injury
Nuriakhmetova, Elina ; Zíková, Martina (advisor) ; Weissová, Romana (referee)
Neural stem cells are undifferentiated cells that are defined by their replication potential and their ability to differentiate into different types of neuronal and glial cells. The adult brain contains two neurogenic zones located in the subventricular zone of the lateral ventricles and in the dentate gyrus of the hippocampus. In both of these zones, neural stem cells produce new neurons. The subject of the bachelor thesis is a summary of current knowledge about neural stem cells and molecular mechanisms underlying changes in neurogenic zones after radiotherapy. At the same time, cell therapies used to minimize damage associated with radiation are discussed.
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The dynamic character of phonetic reductions at the sentence level in spontaneous spoken English
Dalešická, Lucie ; Machač, Pavel (advisor) ; Králová Zíková, Magdalena (referee)
(in English): This bachelor's thesis is concerned with the topic of phonetic reductions in spontaneous speech and its relationship with the recognition of speech units. Research was conducted on the English language using a method previously used as part of a research done on the Czech language. The aim of this research is to tackle questions pertaining to the topics of the existence of a) a unified pattern in the distribution of phonetic reductions in English sentences, b) a possible correlation between a calculated phonetic reduction rate of words and their recognizability, and c) the impact of the so-called 'chunking' on recognizability. The results of this thesis hint at a presence of a pattern in the distribution of phonetic reductions in English, a strong inverse relationship between the rate of phonetic reduction and recognizability, and a notable impact of chunking on perception. This thesis also mentions the influence of regional varieties of English on comprehensibility across those varieties.
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