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The characterisation of organ-specific phytohormone responses to nutrient deficiency and biotic stress
Kramná, Barbara ; Vaňková, Radomíra (advisor) ; Hronková, Marie (referee) ; Plíhalová, Lucie (referee)
Abiotic and biotic stresses lead to crop yield losses and ultimately negatively affect agriculture production. Elucidation of the mechanisms of plant stress responses and their regulation could help to understand plant defence and improve stress tolerance. Phytohormones stand behind both plant growth and developmental changes as well as stress signalling. This thesis summarises the results published in two articles focused on phytohormone dynamics in response to abiotic and biotic stresses, namely phosphate shortage and Plasmodiophora brassicae infection. A review article focuses in depth on strigolactones as master regulators of phosphate deficiency responses. The main emphasis is put on organ-specific reactions and exogenous phytohormone treatment with the potential to convey stress tolerance. In the case of phosphate shortage, the universal reaction in all organs was a decrease in active cytokinin trans-zeatin and gibberellin GA4 with a concurrent elevation of abscisic acid. Also, the high- affinity phosphate transporters (PHT1;4 and PHT1;7) exhibited increased gene expression within the whole plant. Shoot apical meristems showed numerous changes in gene expression and were the most affected organ during the lack of phosphate. Only in roots, we observed a substantial elevation of low active...
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Analysis of the pathways responsible for the resistance of leukemic cells towards L-asparaginase
Šimčíková, Markéta ; Konvalinka, Jan (advisor) ; Poljaková, Jitka (referee)
Acute lymphoblastic leukaemia (ALL) is the most frequent malignancy in childhood. Despite the very successful ALL therapy, relapses occur to 15-20 % of children. One of the possible relaps causes is the resistance to therapeutics. ALL is treated with combined chemotherapy in which cytostatic agent L-asparaginase plays the essen- tial role. L-asparaginase depletes extracellular asparagine and glutamine. Antagonist of the L-asparaginase is asparagine synthetase enzyme, which synthesizes the cellular asparagine. The specific antileukaemic effect of L-asparaginase is believed to be thanks to lower activity of the asparagine synthetase in leukaemic cells comparing to the healthy cells. The asparagine and glutamine deficiency harms the cellular proteosyn- thesis and induces apoptosis. Mechanism of the L-asparaginase cytotoxic effect and mechanism of corresponding resistance is still not fully explained. This bachelor thesis is a part of a project studying mechanisms of leukaemic cells resistance to L-aparaginase. In the model leukaemic REH cell line a deletion del(5)(q34) was discovered, which cannot be found in the resistant clone of these cells. This thesis focuses on proving different sensitivity of leukaemic cells, with or without the deletion, to L-asparaginase. The limiting dilution was used to obtain...
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Ecology of flower smuts (Microbotryum) and their hosts from family Caryophyllaceae
Koupilová, Klára ; Koubek, Tomáš (advisor) ; Marková, Jaroslava (referee)
Anther-smut fungus (Microbotryum spp.) infecting plants of the Caryophyllaceae represents one of the most extensively studied plant pathogen systems. Anther-smut is a pollinator-borne disease that turns infected plants completely sterile. The aim of this thesis is to sum up the main findings about ecology and epidemiology of anther-smut disease and it mainly deals with various factors that influence disease spread and occurrence in nature. According to existing research, abiotic factors play minor role compared to biotic factors and interactions. Among the most pronounced, we can find variability in pathogen virulence and host resistance and also vector behaviour. When studying epidemiology of Microbotryum spp., it is necessary to take account of spatial population structure and metapopulation dynamics as well. Comparing life histories of different host species can also bring useful information. Key words: anther-smut, Microbotryum, Caryophyllaceae, pollinators, resistance, epidemiology, metapopulation dynamics.
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Antibiotic rezistance genes in soil actinobacteria
Patrmanová, Tereza ; Kopecký, Jan (advisor) ; Lichá, Irena (referee)
Actinobacteria are important members of the soil ecosystems, where they are involved in organic matter decomposition. It is worth mentioning that their secondary metabolism allows them to produce a variety of different compounds. These compounds include antibiotics, among them aminoglycosides have a place in clinical practice. These antibiotics are significant due to a broad spectrum of activities against both gram-negative and gram-positive bacteria. However, their use currently carries a risk, mainly their toxicity and development of antibiotic resistance in bacteria. Resistance is the cause of low effectiveness of some of those antibiotics. Actinobacteria as aminoglycoside producers must protect themselves from these compounds, so a variety of resistance types was developed, out of which enzymatic inactivation is the most studied one. Actinobacteria have evolved several mechanisms, which contribute to a resistance to the agents with antimicrobial effects. Genes encoding antibiotic resistance are abundant in soil environment. Their variability is influenced by many factors, especially the selection of bacteria in soil contaminated with antibiotics and also with strains originating from human and animal waste. Significant role has a horizontal gene transfer, which allows distribution of resistence...
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Gene pool of the secondary metabolism in soil bacterial communities
Patrmanová, Tereza ; Kopecký, Jan (advisor) ; Brabcová, Vendula (referee)
The need for new antibiotics and other biologically active compounds is the reason for an increased interest in secondary metabolites of soil bacteria. The phylum Actinobacteria has the dominant position in the soil environment thanks to the potential of producing a broad spectrum of antibiotics and the presence of a number of defense mechanisms preventing the effects of antibiotics. The aim of this thesis was to determine the number of copies of selected secondary metabolic genes in the soils of two sites using designed primers and primers from literature. The design of effective new primers for the detection of selected genes in the soil environment was not achieved in this work, and therefore only primers from literature that had been verified for their specificity were used. In samples taken from soil profiles of two sites, abundances of bacteria, actinobacteria, type II polyketide synthase genes and Erm methyltransferase genes mediating resistance to MLSB antibiotics (macrolides, lincosamides and streptogramins B) were determined by digital PCR. The comparison of the determined copy numbers gave an information about the structure of the bacterial community and the relative abundance of bacteria carrying selected secondary metabolic genes depending on the soil condition changes due to the...
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Gene expression study of oxysterol signal pathway in breast cancer patients
Kloudová, Alžběta ; Souček, Pavel (advisor) ; Vopálenský, Václav (referee)
Hormonal therapy is a common part of breast carcinoma treatment in patients whose tumors express estrogen and progesterone receptors. The aim of hormonal therapy is to prevent proliferative effect of hormones througt their receptor proteins in order to inhibit tumor growth. However, certain number of tumors is resistant to hormonal therapy despite expression of hormonal receptors. Presently, the reasons of this resistance are not fully understood. Oxysterols are hydroxylated cholesterol derivates, which may play some role in development of the resistance. They may interfere with hormonal therapy effect and influence some signal pathways leading to cancer progression. This study comes with results of gene expression of proteins influenced by oxysterol action, metabolic and transport proteins, transcription factors and members of signaling pathways that may be related to oxysterol effect. This thesis identifies some candidate genes for future analysis on the basis of comparison of gene expression between estrogen receptor positive and negative tumors and correlation with clinopathological data. The final goal should lead to discovery of new diagnostic markers for breast cancer therapy. Powered by TCPDF (www.tcpdf.org)
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Antibiotic resistance in clinically important strains of Enterococcus spp.
Kozická, Barbora ; Petráčková, Denisa (advisor) ; Motlová, Lucia (referee)
The Enterococcus spp. is a common part of microflora in the digestive tract; it is used in the food industry and added to probiotics. However, in the last few decades it comes to the fore particularly as a cause of nosocomial diseases. Its importance grows with its increasing resistance to antibiotics. The Enterococcus is intrinsically resistant to many types of antibiotics. In addition to that it may acquire additional resistance determinants by mutations or horizontal gene transfer. This work focuses on the Enterococcus faecium and the Enterococcus faecalis intrinsic and acquired resistances, as these two strains have the major clinical importance. In this work, the most attention is dedicated to the antibiotics vancomycin and linezolid. For several decades, vancomycin was the last treatment option in the case of a failure of commonly used antibiotics. The fact that the resistance to this antibiotic was spreading rapidly became a significant problem in these cases of treatment. Hence the antibiotic linezolid was developed as a response to the growing resistance of gram-positive bacteria to available antibiotics. It is also proved to be effective against the vancomycin- resistant strains E. faecium and E. faecalis.
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Interaction of gilteritinib with OCT1 and OCT2 transporters; relation to conventional therapy of acute myeloid leukemia.
Novotná, Kateřina ; Čečková, Martina (advisor) ; Hofman, Jakub (referee)
Univerzita Karlova Farmaceutická fakulta v Hradci Králové Katedra Farmakologie a toxikologie Student: Kateřina Novotná Supervisor: doc. PharmDr. Martina Čečková, Ph.D. Title of diploma thesis: Interaction of gilteritinib with OCT1 and OCT2 transporters; relation to conventional therapy of acute myeloid leukemia. Gilteritinib is one of the recently approved drugs which is primarily used in the treatment of relapsed/refractory acute myeloid leukemia (AML) with mutated FMS-like tyrosine kinase 3 (FLT3) receptor. In this project, gilteritinib was investigated in terms of its ability to interact with solute carrier (SLC) membrane transporters, namely with OCT1 and OCT2. These membrane proteins play a role in uptake of endogenous compounds and also drugs into the cells of main elimination organs (liver, kidney), but also to cancer cells. In particular, we wanted to examine potential interaction with daunorubicin and mitoxantrone, drugs traditionally used in AML therapy. First, we performed accumulation study and evaluated, whether gilteritinib is potential inhibitor of OCT1 and OCT2 studying differential uptake of daunorubicin and mitoxantrone into MDCKII-OCT1 and MDCKII-OCT2 cells based on OCT1 and OCT2 inhibition by gilteritinib. Secondly, the study evaluating the transfer of gilteritinib across the...
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Root system development under drought stress
Svobodová, Barbora ; Soukup, Aleš (advisor) ; Fendrych, Matyáš (referee)
Plants actively react to the environmental conditions in such a way that they can use their resources efficiently and be resistant to suboptimal living conditions (e.g., high salinity, drought stress, high radiation, extremely high or low temperatures, insufficient nutrients etc.). One of the responses to drought stress (DS) is change in root system architecture (RSA). Optimized shape of RSA during drought stress can be under some situations "Steep, cheap and deep" ideotype. Steep - the roots grow in an angle ideally perpendicular to the soil surface. Cheap - most of the resources are spent on growing deeper while having small diameter and lots of aerenchym tissue. Plants with this RSA modulation try to reach deeper parts of the soil with greater water reservoirs and to achieve this, they use a wide range of mechanisms. Another change in RSA in reaction to drought stress, which directs the root to areas with more water is called hydrotropism. The key signal pathway which activates a large variety of drought responsive genes is the abscisic acid (ABA) pathway. Plants also have epigenetic mechanisms, which by remembering a stress factor they have already encountered, are capable of faster and more intensive response.
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