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Impact of circadian system disruption on development of gastrointestinal disorders
Kubištová, Aneta ; Sumová, Alena (advisor) ; Červená, Kateřina (referee)
The ability to sense 24-hour cycles in external environment and to adapt to them is present in a great array of species living on the Earth. Mammals possess internal time-keeping system which is composed of circadian clocks located in the suprachiasmatic nuclei (SCN) of the hypotalamus and peripheral clocks in various tissues and organs of the body. These clocks are adapting to the changes of external environment, such as light and dark cycles or feeding cycles. Peripheral clocks in the organs of the digestive system are synchronized with the signals derived from the central clock in the SCN and also with signals from food intake. Discordance between these signals may result in development of various diseases of the gastrointestinal tract (GIT) related to insufficient digestion or even in higher risk of developing a cancer. This bachelor thesis is generally aimed at circadian rhythms in the body, with the focus on rhythms in the GIT. It will deal with the importance of the circadian rhythms for correct GIT functions. Furthermore, the thesis is focused on connection between the desynchonization of the circadian clock and GIT disease development, namely of obesity and cancer.
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Molecular mechanisms of entrainment of the fetal circadian clocks
Lužná, Vendula ; Sumová, Alena (advisor) ; Šauman, Ivo (referee) ; Štaud, František (referee)
In order to adapt to changing external conditions, organisms developed the endogenous biological clock for predicting daily alterations. This so-called circadian system drives functions and processes in the whole body with an approximately 24h period. The central oscillator, located in hypothalamic suprachiasmatic nuclei (SCN), is synchronized by light and subsequently sends the information about the time of the day to the rest of the body. Even in the ontogenesis, the functional SCN clock is crucial for proper development as well as health later in life. Since the maturation of embryonic SCN is not completed before birth, maternal signals seem to play a fundamental role in setting and synchronizing the fetal clock. During my PhD studies, we focused on elucidating the nature of maternal signals and their diverse impact on fetal SCN of rat and mouse models. We have revealed that developing SCN is able to sense distinct signals related to various maternal behavioral regimes. Importantly, we have discovered eminent role of glucocorticoids in synchronizing the fetal SCN, along with their ability to accelerate SCN development. These observations point out the importance of regular daily routine and noxious effect of stress during pregnancy. Since the mother communicates with the fetus through placenta...
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Impact of circadian system disruption on development of gastrointestinal disorders
Kubištová, Aneta ; Sumová, Alena (advisor) ; Červená, Kateřina (referee)
The ability to sense 24-hour cycles in external environment and to adapt to them is present in a great array of species living on the Earth. Mammals possess internal time-keeping system which is composed of circadian clocks located in the suprachiasmatic nuclei (SCN) of the hypotalamus and peripheral clocks in various tissues and organs of the body. These clocks are adapting to the changes of external environment, such as light and dark cycles or feeding cycles. Peripheral clocks in the organs of the digestive system are synchronized with the signals derived from the central clock in the SCN and also with signals from food intake. Discordance between these signals may result in development of various diseases of the gastrointestinal tract (GIT) related to insufficient digestion or even in higher risk of developing a cancer. This bachelor thesis is generally aimed at circadian rhythms in the body, with the focus on rhythms in the GIT. It will deal with the importance of the circadian rhythms for correct GIT functions. Furthermore, the thesis is focused on connection between the desynchonization of the circadian clock and GIT disease development, namely of obesity and cancer.
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Molecular mechanisms of circadian clock entrainment by daily regime in food intake
Kapoun, Jiří ; Sumová, Alena (advisor) ; Červená, Kateřina (referee)
Circadian clocks form an endogenous time-keeping system present in most organisms, synchronizing physiological and behavioural processes with perodically changing environmental conditions. The system comprises of the master clock in the suprachiasmatic nuclei of the hypothalamus and numerous subsidiary clocks in peripheral tissues. Its molecular design is constituted by the clock genes, which are rhythmically expressed, form a series of transcriptional/translational feedback loops and influence the expression of various other genes involved in metabolic pathways. The peripheral clocks are dependent on the master clock, although they can be entrained with external cues like food intake timing and diet composition. This desynchronization leads to the distruption of clock gene oscillation, which can potentially have serious impact on metabolic processes and increase the risk of metabolic disorders. The aim of this thesis is to summarize current knowledge on the relationship of molecular chronobiology and nutrition with a focus on the molecular mechanisms through which can food, especially its intake timing and composition, influence the crosstalk between clock gene expression and cellular metabolism. The thesis also emphasises the potential effect of circadian clock disruption on the risk of metabolic...
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Ofukování termického proudu plazmatu generovaného plazmatronem
Kavka, Tetyana ; Hrabovský, Milan ; Chumak, Oleksiy ; Kopecký, Vladimír
The ambient air is entrained intensively into atmospheric pressure thermal plasma jets. A system for shielding plasma jet has been used to improve jet characteristics and reduce oxygen content. Different gases have been applied as a shroud gas – argon, acetylene, methane, mixtures of acetylene-nitrogen and hydrogen-nitrogen. All shroud gases used in experiments affected plasma jet making the profiles of the jet characteristics flattened with higher temperatures and velocities and reduced amount of oxygen.
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