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CIrcadian regulation of miRNA and clock-controlled genes in tumorigenesis
Balounová, Kateřina ; Pácha, Jiří (advisor) ; Bendová, Zdeňka (referee)
The circadian clock generates circadian rhythms, which participate on regulation of a number of signalling pathways. Disruption of the circadian regulatory mechanism is linked to a development and a progression of certain types of cancer including colorectal tumorigenesis. Progression of tumorigenesis depends on the cell cycle machinery related to cell proliferation and apoptosis. MiRNAs play a role in initiation and progression of tumorigenesis because they interfere in regulatory pathways associated with tumorigenesis. The aim of the thesis was to determinate existence of circadian rhytms in clock controlled genes (Tef, Dbp), miRNAs (miR-1-3p, miR-16-5p, miR-34a-5p, miR-155-5p, miR-192-3p) and genes of the cell cycle machinery (Ccnd1, Ccne1, Ccna1, Ccnb1) and apoptosis (Casp3, Bcl2, Bad). Further, to compare detected circadian rhythms during aging and neoplastic transformation of colon by quantitative RT-PCR. We have observed circadian expression of Tef, Dbp, Ccne1, Ccna1, Ccnb1, Casp3 and Bcl2 in young mice colon, Tef, Dbp, miR-1-3p, Ccne1, Ccna1 in old mice colon and Tef and Dbp in colorectal tumors. In summary, circadian expression of clock controlled genes varied but was maintained in mice colorectal tumors. In aging we demonstrated weakening of circadian rhythms of the genes of the cell...
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Iron and copper metabolism in marine microalgae of the genus Ostreococcus
Pilátová, Jana ; Šuťák, Róbert (advisor) ; Falteisek, Lukáš (referee)
The smallest free living eukaryote known as Ostreococcus tauri became along with some related species great experimental models for iron uptake research in marine picoplankton. The ecological context of such topic is very interesting considering the nature of adaptation to iron limitation and its connection to the copper metabolism. Our experiments has simulated iron and copper limiting conditions of the ocean, as a control we used iron and copper repleted cultivation media. The maximum cell counts were two- to threefold higher in iron-repleted medium compared to iron- depleted one. There was the only exception showing no difference in growth - O. lucimarinus coming from open ocean with high irradiance levels and very low iron concentrations, which all together made it the best adapted species. The reinoculation of cell cultures after a week cultivation into to the same iron/copper containing media led to unmasking the copper effect on growth, which was much weaker than encountered with iron (again except of O. lucimarinus). Iron sufficiency positively affects heme b and chlorophyll a and b content with no significant copper dependency. The circadian timing of heme b and chlorophyll a and b content shows the increasing trend during the day followed by decrease at night. This might be caused by...
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Circadian regulation of sleep during ontogenesis in humans
Grieblová, Adéla ; Sumová, Alena (advisor) ; Soták, Matúš (referee)
The circadian system has evolved as an adaptation to periodically changing conditions on Earth. In mammals, and therefore in humans, the circadian system consists of the central and perip- heral oscillators generating a circadian rhythm. One of the most significant process exhibiting circadian rhythm is the sleep-wake cycle. Sleep is regulated by cooperation of circadian and homeostatic process. There are changes in circadian regulation of sleep during ontogenesis in human. The changes mainly releate to chronotype, i.e., to the diurnal preferences of activity and sleep. In the first years of life, there is a typical morning chronotype. In the end of first decade of life, the circadian phase begins to delay and reaches its maximal eveningness during ado- lescence. In adulthood, the preference changes again toward morning chronotype and reaches extreme morningness in elderly. Changes in circadian regulation of sleep during ontogenesis depend not only on age, but also on sex. 1
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Role of microRNA in regulations of circadian rhythms and tumorigenesis
Balounová, Kateřina ; Pácha, Jiří (advisor) ; Červená, Kateřina (referee)
MicroRNAs (miRNAs) are ~22nt long single-strand RNA found in all groups of organisms, where they affect biochemical, physiological and behavioral pathways by regulation of protein expression. Regulation of protein expression is mediated by silencing mRNA of target genes in one of two processes, translation repression or degradation of mRNA. Changed expression of miRNA can lead to aberrant regulatory pathways resulting in various pathophysiological conditions like cardiovascular diseases, cancer or neurological disorders. MiRNA can play a role in cancer both as an oncogen or as a tumor suppressor, and it is tissue and cancer-type specific. In colorectal cancer miRNAs downregulate or upregulate signaling pathways including key processes involved in cancer development, like proliferation, cell cycle, apoptosis and metastasis formation. Circadian clock in mammals synchronizes cellular and physiological processes by transcriptional-translational feedback loops. Not only miRNAs regulate the levels of key clock genes and clock controlled genes, but also a number of miRNAs exhibit circadian expression. Therefore aberrant circadian rhythms increase risk of colorectal cancer also by altered expression of miRNAs. The main aim of the thesis was to identify miRNAs, which regulate both tumorigenesis and circadian...
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Circadian rhythm of parathyroid hormone and bone remodeling: implication for the osteoporosis treatment with teriparatide (parathormone [1-34])
Rašková, Mária ; Zikán, Vít (advisor) ; Žofková, Ivana (referee) ; Perlík, František (referee)
Circadian rhythm of parathyroid hormone (PTH) is well documented, but its physiological role is not fully understood. In healthy individuals, biochemical markers of bone remodeling follow a similar circadian rhythm to PTH with a nocturnal rise in bone resorption and formation. The loss of PTH diurnal variation was observed not only in primary hyperparathyroidism, but also in patients with postmenopausal osteoporosis. Continuously elevated concentrations of PTH lead to excessive stimulation of bone resorption, whereas intermittent PTH administration has a strong osteoanabolic effect in patients with osteoporosis. It has not been examined whether the skeletal sensitivity to PTH action depends also on the time of its application. The aim of our study was to verify the hypothesis that the application of teriparatide (TPTD, recombinant human PTH [1-34]) at different times of the day in the context of its diurnal variability affects the physiological circadian rhythm of bone remodeling and also the bone mineral density (BMD) after the long-term TPTD treatment. Fourteen women with postmenopausal osteoporosis treated with 20 micrograms of TPTD daily, applied subcutaneously either in the morning or evening, were included in the first study. The concentration of serum C-terminal telopeptide of type I collagen...
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The effect of the blue light on the human body
Dvořák, Petr ; Krbal, Michal (referee) ; Štěpánek, Jaroslav (advisor)
This thesis explains the term „blue light“. It deals with the sources of blue light and the effects of this type of electromagnetic radiance on human body. The focus is concentrate especially on problems, which are evocated of blue light. The biggest danger is the desynchronization of circadian rhythm and photochemical damage of retina – photoretinitis („blue light hazard“). The basic principles of biological processes and the visual system are described here. These processes are controlled by properties of incident light onto the retina of eye. The basic information about artificial sources of blue light commonly used in households and in industry are mentioned in the second half of work. These light sources were measured and elaborated. The electromagnetic spectrums of sources are portrayed and there is a comparison of sources due circadian effect too.
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Motion mode and circadian typology of urban children in primary school (Research in Strakonice)
DUNOVSKÁ, Klára
The presented thesis explores exercise regimen, circadian rhythms and eating habits of young children living in an urban area. In the theoretical part the thesis deals with the importance of sleeping mode and its impact on the mental and physical balance together with the specificity of this age group in relation to their mental and physical condition. The research section assesses the results of the survey using quantitative questionnaires ?CIP? (Harada, KREJČÍ 2010) and ?Time day Snaphot? of primary school children. One hundred and thirteen questionnaires of primary school children in the age of ten who attend basic schools in Strakonice were processed in total. The result shows violation of sleeping habits. Most of the children are early birds and the total amout of their physical exercise is satisfactory.
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Circadian rhythm of secondary alga Chromera velia
JONÁKOVÁ, Martina
A life cycle of many known algae is influenced by the circadian clock. It seems probable that also Chromera velia, the closest known photosynthetic relative to Apicomplexa, uses circadian oscillator. We tested, if fluctuating of zoospore?s abundance is driven by the circadian clock. This rhythm is stable even in the constant light condition. Furthermore, three cryptochrome genes, involved in circadian rhythms, were sequenced and consequently phylogenetically investigated. Two of them were classified as CRY-DASH, the third is CRY-DASH-like. The rhythmicity of CRY-DASH expression in C. velia was also investigated. The level of expression was also tested under constant light and dark condition. It was suggested that expression of these genes is associated with the circadian oscillator. This is the first study of the circadian clock in C. velia.
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