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The morphology and activity of selected avalanche paths in the Hrubý Jeseník Mts. and the Králický Sněžník Mts.
Krause, David
The occurrence of avalanche paths is usually frequent in alpine environment, but it is also present in mid-mountains such as the High Sudetes. The submitted master thesis is focused on avalanche paths in the Eastern High Sudetes. The morphometric analysis of 8 paths was accomplished to determine their characteristics and comparison with statistical verification. The dendrogeomorphological analysis and further geomorphological mapping was performed in 2 selected paths (Sněžná kotlina and Králický Sněžník) to cover their avalanche activity frequency and to find relationship between their activity and morphology. The results of this study show that there is a strong difference between two groups of avalanche paths in the Eastern High Sudetes. The Sněžná kotlina and The Králický Sněžník avalanche paths are longer and narrower than the other paths. They also have higher elevation difference. The comparison of these two paths performed by dendrogeomorphology indicates higher avalanche activity frequency in the Sněžná kotlina path, which was strengthened after strong avalanche event in 2004. It is assumed that the Sněžná kotlina path contains advanced avalanche landform, which is a long gully, probably also affected by debris- flows in the past. On the other hand the Králický Sněžník path is rather less...
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Influence of bird schistosome Trichobilharzia regenti on haemocyte activity of lymnaeid snails
Skála, Vladimír
Gastropod molluscs are naturally exposed to various pathogens such as bacteria, or multicellular parasites that include digenetic trematodes (digeneans) which develop in snails. To combat these pathogens gastropods have evolved a sophisticated internal defence system that is composed of humoral and cellular arms. Lectins are probably the most important humoral components, whereas haemocytes represent the main effector cells. Immunity is one of the important factors determining compatibility/non-compatibility of gastropods and pathogens (particularly snails and trematodes). The introductory part of this thesis includes a review of literature focused on the components of the gastropod immune system and their reactions against pathogens represented by bacteria and digeneans. Additionally, selected immunomodulations caused by compatible digenean species are reviewed. Experimental work (presented in publications) focused mainly on the influence of the bird schistosome Trichobilharzia regenti on haemocyte activities of two lymnaeid snail species, Radix lagotis and Lymnaea stagnalis that are susceptible or refractory to the parasite, respectively. This schistosome parasite causes neuromotor disorders in specific definitive hosts (waterfowl), but it also causes cercarial dermatitis in accidental hosts...
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Transgene silencing in potato plants and tobacco cell line BY-2
Tyč, Dimitrij
Accidental discovery of RNA interference in plants a few decades ago and its description by Fire et al. (1998) brought a real revolution in molecular biology and in many other branches of biology. Researchers have uncovered a large and unexpected mechanism of regulation of gene expression at many levels in almost all studied eukaryotes. The first studies have revealed silencing of both exogenous and endogenous genes in plants. So, it soon became clear that this process serves to organisms not only in the defense against viruses, but also against mobile genetic elements as well as in modulation of expression own genes. The key role in all RNAi mechanisms is played by dsRNA that is processed into small RNAs. In association with a number of other proteins, small RNAs can direct either cleavage of complementary or nearly complementary mRNAs or block their translation in the process of posttranscriptional gene silencing (PTGS). Additionaly, sRNAs can affect gene expression at transcriptional level via modifying DNA in a process called RNA dependent DNA methylation (RdDM). In plant transformation, RNAi cause variability amongst transgene lines and instability in the expression of introduced genes, which complicates the use of transgenic lines, because many biotechnological approaches require a defined...
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Membrane fluidization by alcohols inhibits DesK-DesR signalling in Bacillus subtilis
Vaňousová, Kateřina ; Mikušová, Gabriela (referee)
After cold shock, the Bacillus subtilis desaturase Des introduces double bonds into the fatty acids of existing membrane phospholipids. The synthesis of Des is regulated exclusively by the two-component system DesK/DesR; DesK serves as a sensor of the state of the membrane and triggers Des synthesis after a decrease in membrane fluidity. The aim of our work is to investigate the biophysical changes in the membrane that are able to affect the DesK signalling state. Using linear alcohols (ethanol, propanol, butanol, hexanol, octanol) and benzyl alcohol, we were able to suppress Des synthesis after a temperature downshift. The changes in the biophysical properties of the membrane caused by alcohol addition were followed using membrane fluorescent probes and differential scanning calorimetry. We found that the membrane fluidization induced by alcohols was reflected in an increased hydration at the lipid-water interface. This is associated with a decrease in DesK activity. The addition of alcohol mimics a temperature increase, which can be measured isothermically by fluorescence anisotropy. The effect of alcohols on the membrane periphery is in line with the concept of the mechanism by which two hydrophilic motifs located at opposite ends of the transmembrane region of DesK, which work as a molecular...
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Lower secondary school pupil's evaluation of biology fields and their attitude toward biology
Malcová, Kateřina ; Čížková, Věra (referee)
Natural sciences are being less attractive for pupils in past few years. One of teachers'goals should be the effort to motivate pupils in all possible ways to study natural sciences. A whole range of factors, as sex, age, place of residence, teacher or the popularity of branches of biology, is being reflected in pupils' attitude toward biology. That is why it is important to research these attitudes and their influences. If teachers know how pupils feel about specific branches of biology, they can modify way of teaching unpopular topics to make them more attractive. It can positively affect pupils' attitude to biology as a whole. This thesis is based on research about evaluation of branches of biology which was done with 550 pupils from 6th to 9th grades of lower secondary school and lower grades of grammar school. This research was published as an article "How do lower secondary school pupils evaluate branches of biology?" and it is part of the thesis. The results showed that the most popular branches of biology are zoology and human biology. Unpopular branches are protozoology, geology and mycology. Evaluation was affected by these factors: sex, grade, type of school (primary school x lower grammar school) and the teacher. This thesis introduces the problematics of attitudes, specifically to...
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Spatial cognition in rats: processing of information about the position of distant object
Levčík, David
Spatial behavior is widely studied to understand cognition and its neurophysiological substrate. Hippocampus plays a crucial role in many spatial tasks. It is unclear whether hippocampus is necessary for recognizing position of distant objects located in inaccessible space. To address this question we developed a novel operant-conditioning task in which rats recognize position of an object located in an inaccessible space. We assessed the role of the dorsal hippocampus in the task by blocking its activity with muscimol. Our results showed that intact rats use the dorsal hippocampus for recognizing position of the distant object located in the inaccessible part of the environment. In addition, we showed that the cognitive performance in the task is not affected by the changes in motor activity induced by prazosin. Key words: spatial cognition, operant conditioning, hippocampus, muscimol, prazosin
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Key factors in soil organic matter accumulation
Vindušková, Olga
Soil organic matter (SOM) is highly important for soil quality and the global carbon cycle. SOM content is influenced by a complex interplay of many different factors such as time, climate, parent material, vegetation, and others. The effect of time is often studied using the chronosequence approach using a set of study sites differing in age but comparable in other soil-forming factors. The effect of other factors can be studied by comparing two or more chronosequences. An important assumption of these approaches is that the SOM quantification methods produce comparable results both among sites of each sequence and among different sequences. In this thesis, I explored the key factors in SOM accumulation and dealt with SOM quantification methods. I studied SOM accumulation in two model situations - in post-mining sites after open-cast coal and oil shale mining and in landslides in the Western Carpathians. The results of this thesis are summarized in one book chapter accepted for publication and four papers, out of which three have been published and one is prepared for publication in an international journal with impact factor. The key factor affecting the rate of SOM accumulation after a major disturbance is time. The accumulation rates found in the first 40 to 100 years in both post-mining sites...
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Determination of erosion thickness of Brno Tegl
Malát, Richard
The thesis deals with an application of the geotechnical numerical back analysis and several other geotechnical conventional techniques in estimating the thickness of eroded sediments. Investigated strata is the Lower Miocene marine clay, often called "Tegl" which was deposited in the Carpathian Foredeep in the eastern part of the Czech rep. Numerical back analysis is based on an assumption that erosion thickness of a soil can be derived from its stress sate represented by K0 coefficient (coefficient of earth pressure at rest). The erosion thickness given by the numerical back analysis is compared with two estimations using Baldwin-Butler's equation and Casagrande's concept of preconsolidation stress. The erosion thickness is also derived from K0 values given by two field probes: Flat dilatometer (DMT) and Push-in spade shaped pressure cell (PSPC). The numerical back analysis was applied to galleries and adits opened during site investigation of the Královo Pole Tunnels in Brno. Both the samples for laboratory analyses were taken and the field tests were carried out in area of Brno city. Discrepancy of the results is analyzed and the conclusion is that the results given by the four conventional mentioned techniques (Baldwin-Butler, Casagrande, DMT, PSPC) are strongly distorted if the investigated...
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The wider context of the impact of solar activity on mortality by cause in the Czech Republic
Podolská, Kateřina
The wider context of the impact of solar activity on mortality by cause in the Czech Republic Abstract The presented dissertation investigates the influence of extraterestrial phenomena, in the whole scope of their possible effects, on human population. It analyses the influence of climate-change induced fluctuation of solar activity on the population, as well as the impact of the concentration of cosmogenic radionuclides on human health. In the introduction, the manifestation of solar activity on Earth is described, the results of the present research is summarized, and the used methods of data processing and the data sources are described. The primary focus of this work is the association of mortality from the causes of death recorded under chapter IV. Diseases of the nervous system and chapter IX. Diseases of the circulatory system of the International Classification of Diseases, 10th revision (ICD-10) in the Czech Republic with the changes in the level of solar activity and its exceptional fluctuations. The main aim is to determine the possible link between the daily numbers of dead by the respective causes of death, by sex and age groups in the Czech Republic, on global as well as on geographically specific daily values of solar, ionospheric, and geomagnetic parameters in the years 1994-2013. These are...
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The role of alternative sigma factors of RNA polymerase in regulation of gene expression in Corynebacterium glutamicum
Šilar, Radoslav
Abstract Regulation of transcription by extracytoplasmic-function (ECF) sigma factors of RNA polymerase is an efficient way of cell adaptation to diverse environmental stresses. Amino acid- producing gram-positive bacterium Corynebacterium glutamicum codes for seven sigma factors: the primary sigma factor SigA, the primary-like sigma factor SigB and five ECF stress- responsive sigma factors (SigC, SigD, SigE, SigH and SigM). The sigH gene encoding SigH sigma factor is located in a gene cluster together with the rshA gene, encoding the anti-sigma factor of SigH. Anti-sigma factors bind to their cognate sigma factors and inhibit their transcriptional activity. Under the stress conditions the binding is released allowing the sigma factors to bind to the RNAP core enzyme. In this thesis, regulation of expression of genes encoding the most important ECF sigma factor SigH and its anti-sigma factor RshA as well as genes belonging to the SigH-regulon were mainly studied. The transcriptional analysis of the sigH-rshA operon revealed four housekeeping promoters of the sigH gene and one SigH-dependent promoter of the rshA gene. For testing the role of the complex SigH-RshA in gene expression, the C. glutamicum ΔrshA strain was used for genome-wide transcription profiling with DNA Microarrays technique under...
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