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Identification and modeling of gene expression regulatory networks during streptomycetes germination
Straková, Eva ; Vohradský, Jiří (advisor) ; Stopka, Pavel (referee) ; Vondrášek, Jiří (referee)
Streptomycetes have been studied mostly as producers of antibiotics and for fundamentals of complex bacterial cell development. Here, transcriptomic and proteomic approaches were applied to systems study of Streptomyces coelicolor germination as a developmental transition from dormancy to the vegetative stage. The time dynamics of the gene expression levels represented by mRNA and intracellular protein accumulation and synthesis were measured throughout 5.5 h of germination at 13 time points by employing both DNA microarray and two-dimensional gel electrophoresis techniques. Using a numerical model of gene expression, genetic networks were reconstructed and functional groups of genes controlled by the sigma factors were identified. Modeling of the regulatory interactions provided a set of parameters allowing simulate kinetics of gene expression control among the sigma factors and their target genes. Particularly regulons of two sigma factors, SigR and HrdD, were identified. The analysis assigned their key role during the germination process. Analysis of global trends in the gene/protein expression revealed that the full capability of regulatory mechanisms responding to the environmental cues is reached within the first hour of germination, and identified the basic gene/protein functional groups...
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Structure and function of the invasion apparatus of microsporidia
Dohnálek, Vít ; Doležal, Pavel (advisor) ; Vávra, Jiří (referee)
Microsporidia are obligate intracellular parasites that cause significant economic damage and can infect humans. They had evolved highly specialized invasion apparatus that is unique to them. During the invasion the sporoplasm is released from the spore wall and it is transferred to the host cytoplasm through the polar tube. Current research on the invasion apparatus has been focused mainly on the polar tube that is its most prominent structure. Polaroplast and posterior vacuole remain out of the main interest, although they are necessary for the activation and execution of the invasion. If the right combination of environmental factors occurs, the organization of the polaroplast begins to change, the posterior vacuole starts to swell and the polar tube is discharged. Sporoplasm is eventually pushed through the tube into the host cell by growing posterior vacuole. The mechanism has not been explained yet however plenty of theories are trying to explain the germination. This work summarizes current theories and knowledge of structure and function of particular parts of the invasion apparatus. Key words: Microsporidia, invasion, polar tube, intracellular parasitism, germination
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The invasion apparatus of protozoan parasites
Novotná, Veronika ; Petrů, Markéta (advisor) ; Štáfková, Jitka (referee)
Protozoa parasitism has evolved many times independently in the history of eukaryotes. Some organelles were reduced, and specific invasion apparatuses were developed by adapting to the host. These apparatuses help to penetrate host cells and escape the immune system. The thesis summarizes the findings of the invasion apparatus and invasion of four selected unicellular protozoan parasites of genus Plasmodium, Microsporidia, Ichthyobodo and Rozella. Each chapter includes general knowledge of the parasite, its structure and life cycle. Keywords: Apicomplexa, Plasmodium, Microsporidia, Ichthyobodo, Rozella, merozoite, glideosom, moving junction, polar tube, germination, cytostome, zoospore, germ tube;
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Structure and function of the invasion apparatus of microsporidia
Dohnálek, Vít ; Doležal, Pavel (advisor) ; Vávra, Jiří (referee)
Microsporidia are obligate intracellular parasites that cause significant economic damage and can infect humans. They had evolved highly specialized invasion apparatus that is unique to them. During the invasion the sporoplasm is released from the spore wall and it is transferred to the host cytoplasm through the polar tube. Current research on the invasion apparatus has been focused mainly on the polar tube that is its most prominent structure. Polaroplast and posterior vacuole remain out of the main interest, although they are necessary for the activation and execution of the invasion. If the right combination of environmental factors occurs, the organization of the polaroplast begins to change, the posterior vacuole starts to swell and the polar tube is discharged. Sporoplasm is eventually pushed through the tube into the host cell by growing posterior vacuole. The mechanism has not been explained yet however plenty of theories are trying to explain the germination. This work summarizes current theories and knowledge of structure and function of particular parts of the invasion apparatus. Key words: Microsporidia, invasion, polar tube, intracellular parasitism, germination
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Effect of heavy metal ions on Norway spruce embryos
?or?ević, Dragana
Aim of this work was to evaluate effect of copper and arsenic on Norway spruce embryogenic cell masses (ECMs) in different concentrations during 14 days proliferation period but as well during maturation and germination stages. Copper in lower concentrations increased the growth of ECMs while in higher concentrations growth was inhibited. Arsenic in concentrations 50, 250 and 500 uM showed very high toxicity and after 14 days proliferation period all ECMs were dead. In experiments with lower concentrations (10 and 25 uM), control had highest proliferation ratio while arsenic had insignificant difference on growth. Cell line I-1-3 had higher proliferation ratio and produced more somatic embryos during maturation in comparison with cell line III-3-3, respectively. After maturation certain number of abnormally developed cotyledonary somatic embryos was obtained. Norway spruce as a fast growing conifer tree is one of the most widely planted spruces and one of the most economically important species in Europe. The results of this thesis can help to understand effect of two tested metals on somatic embryogenesis but as well can be used for investigation of two tested clones in polluted soils.
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Identification and modeling of gene expression regulatory networks during streptomycetes germination
Straková, Eva ; Vohradský, Jiří (advisor) ; Stopka, Pavel (referee) ; Vondrášek, Jiří (referee)
Streptomycetes have been studied mostly as producers of antibiotics and for fundamentals of complex bacterial cell development. Here, transcriptomic and proteomic approaches were applied to systems study of Streptomyces coelicolor germination as a developmental transition from dormancy to the vegetative stage. The time dynamics of the gene expression levels represented by mRNA and intracellular protein accumulation and synthesis were measured throughout 5.5 h of germination at 13 time points by employing both DNA microarray and two-dimensional gel electrophoresis techniques. Using a numerical model of gene expression, genetic networks were reconstructed and functional groups of genes controlled by the sigma factors were identified. Modeling of the regulatory interactions provided a set of parameters allowing simulate kinetics of gene expression control among the sigma factors and their target genes. Particularly regulons of two sigma factors, SigR and HrdD, were identified. The analysis assigned their key role during the germination process. Analysis of global trends in the gene/protein expression revealed that the full capability of regulatory mechanisms responding to the environmental cues is reached within the first hour of germination, and identified the basic gene/protein functional groups...
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