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Oxidative damage to cellular components after oxidative stress induction by specific herbicides
Kramná, Barbara ; Wilhelmová, Naďa (advisor) ; Ryšlavá, Helena (referee)
Oxidative stress is caused by overproduction and overaccumulation of ROS (reactive oxygen species). This state is responsible for cellular damage during unfavorable environmental conditions such as drought, low temperatures, salinity. In order to directly study oxidative stress at tobacco plants (Nicotiana tabacum cv. Xanthi) I used specific herbicides, MV (methyl viologen) and 3-AT (3- aminotriazole). There were several markers used for monitoring oxidative damage to cellular components: DNA damage detected by a comet assay, lipid peroxidation, carbonylated proteins and modification of activities of antioxidant enzymes CAT (catalase) and APX (ascorbate peroxidase). Fluorescent microscopy documented changes in a redox state of tobacco cells and a specific signal for peroxisomes was observed after treatment with higher concentrations of MV and 3-AT. Application of both herbicides caused significant DNA damage, while they worked in a different concentrations, MV in µM and 3-AT in mM. Another convincing oxidative stress marker for MV was protein carbonylation. The inhibition of antioxidant enzymes CAT and APX was less significant when compared to the effects of 3-AT. Decreasing membrane stability proved to be an universal oxidative stress marker for both herbicides. On the other hand, lipid...
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Effect of chronic hypoxia on antioxidative capacity of rat myocardium.
Závišková, Kristýna ; Nováková, Olga (advisor) ; Žurmanová, Jitka (referee)
Adaptation to chronic hypoxia activates endogenous signaling cascades, which lead to cardiac protection against acute ischemia/reperfusion (I/R) injury. The molecular mechanism of this phenomenon has not been fully clarified yet. However, it was proved that reactive oxygen species (ROS) take part in cardioprotective signaling pathway inducted by chronic hypoxia. The high level of ROS must be precisely regulated by antioxidative system of a cell. The aim of diploma thesis was to examine the effect of intermittent hypobaric hypoxia (IHH, 7 000 m) on relative amount of antioxidative enzymes (peroxiredoxin 6 - PRX6, thioredoxin 1 and 2 - TRX1 and TRX2, thioredoxin reductase 1 - TRXR1) and also enzymes of iron metabolism (heme oxygenase 1 and 2 - HO1 and HO2, aconitase 1 and 2 - ACO1 and ACO2), which participate in regulation of cell redox state. Moreover, we studied the effect of adaptation to IHH and an antioxidant tempol on relative amount of calcium-independent phospholipase A2 (iPLA2). iPLA2 can remove peroxidized fatty acids from membrane phospholipids. On the other hand, iPLA2 can damage cell in I/R conditions. All enzymes were studied in homogenates from normoxic and IHH adapted rat left ventricular myocardium by Western blot. Adaptation to IHH caused a decrease of PRX6 and on the opposite an increase of...
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Factors affecting uptake and distribution of uranium in plants.
Krejčová, Daniela ; Lhotáková, Zuzana (advisor) ; Tylová, Edita (referee)
Uranium is a radionuclide, which naturally occurs in Earth's soil in rather an insignificant amount. It is not very dangerous in such small concentration; however, this concentration is rising due to anthropogenic activity, therefore an estimation of its increase is at hand. It is necessary to research possibilities of not only effective, but also ecological extermination of this contamination. Phytoremediation could be an appropriate solution, but this method is still in its beginning stages when it comes to uranium contaminations. That's why we need to study influences of uranium on plants and find out to what extent are they suitable for phytoremediation of areas contaminated by uranium. Phytoremediation methods are based on the abilities of plants to receive and accumulate certain pollutants. The factors that influence the amount of uranium received by a plant can be divided into four groups: plant species, uranium's oxidation levels, pH of of the medium or the substrate and ligand, which is attached to the uranium (Mitchell, 2013). Transportation of uranium to the aboveground part of the plant is also a factor here. Plants need to deal with the accepted uranium; aside from the radiological risks resulting from the characteristics of radioisotope, uranium is also a heavy metal. Chemical...
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Accumulation and localization of secondary metabolites with protective function in grain crops growing under elevated CO2 concentration and selected stress factors of climate change.
Mastiláková, Monika ; Albrechtová, Jana (advisor) ; Votrubová, Olga (referee)
An ongoing climate change exposes plants to a whole range of environmental factors contributing to ever-increasing stressful conditions. The stress response of plants can reduce the yield of cereals, which make up a large part of food, thus increasing a threat to food security. It is therefore important to cultivate stress-resistant plants to ensure food security. The ability to cultivate resistant plants requires to understand their defensive mechanisms. Non-specific stress indicators with a protective function, such as phenolic compounds (FLs), help to determine the stress response of plants. The aim of the present review is to summarize the knowledge about the effects of stress factors imposed by climate change on the accumulation and localization of secondary metabolites, with protective function in cereals, especially in barley (Hordeum vulgare L.). Further, to summarize the available information about the methods, which are used to detect and localize secondary metabolites in leaf tissues. For detailed detection and determination of FL's content we can use chromatographic methods, e.g. HPLC. More accurate localization of FLs in tissues and cells requires the use of histochemical detections. One of the most commonly used methods is the method of Neu's reaction using fluorescence microscopy. The...
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Factors affecting uptake and distribution of uranium in plants.
Krejčová, Daniela ; Lhotáková, Zuzana (advisor) ; Tylová, Edita (referee)
Uranium is a radionuclide, which naturally occurs in Earth's soil in rather an insignificant amount. It is not very dangerous in such small concentration; however, this concentration is rising due to anthropogenic activity, therefore an estimation of its increase is at hand. It is necessary to research possibilities of not only effective, but also ecological extermination of this contamination. Phytoremediation could be an appropriate solution, but this method is still in its beginning stages when it comes to uranium contaminations. That's why we need to study influences of uranium on plants and find out to what extent are they suitable for phytoremediation of areas contaminated by uranium. Phytoremediation methods are based on the abilities of plants to receive and accumulate certain pollutants. The factors that influence the amount of uranium received by a plant can be divided into four groups: plant species, uranium's oxidation levels, pH of of the medium or the substrate and ligand, which is attached to the uranium (Mitchell, 2013). Transportation of uranium to the aboveground part of the plant is also a factor here. Plants need to deal with the accepted uranium; aside from the radiological risks resulting from the characteristics of radioisotope, uranium is also a heavy metal. Chemical...
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Oxidative damage to cellular components after oxidative stress induction by specific herbicides
Kramná, Barbara ; Wilhelmová, Naďa (advisor) ; Ryšlavá, Helena (referee)
Oxidative stress is caused by overproduction and overaccumulation of ROS (reactive oxygen species). This state is responsible for cellular damage during unfavorable environmental conditions such as drought, low temperatures, salinity. In order to directly study oxidative stress at tobacco plants (Nicotiana tabacum cv. Xanthi) I used specific herbicides, MV (methyl viologen) and 3-AT (3- aminotriazole). There were several markers used for monitoring oxidative damage to cellular components: DNA damage detected by a comet assay, lipid peroxidation, carbonylated proteins and modification of activities of antioxidant enzymes CAT (catalase) and APX (ascorbate peroxidase). Fluorescent microscopy documented changes in a redox state of tobacco cells and a specific signal for peroxisomes was observed after treatment with higher concentrations of MV and 3-AT. Application of both herbicides caused significant DNA damage, while they worked in a different concentrations, MV in µM and 3-AT in mM. Another convincing oxidative stress marker for MV was protein carbonylation. The inhibition of antioxidant enzymes CAT and APX was less significant when compared to the effects of 3-AT. Decreasing membrane stability proved to be an universal oxidative stress marker for both herbicides. On the other hand, lipid...
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Effect of chronic hypoxia on antioxidative capacity of rat myocardium.
Závišková, Kristýna ; Nováková, Olga (advisor) ; Žurmanová, Jitka (referee)
Adaptation to chronic hypoxia activates endogenous signaling cascades, which lead to cardiac protection against acute ischemia/reperfusion (I/R) injury. The molecular mechanism of this phenomenon has not been fully clarified yet. However, it was proved that reactive oxygen species (ROS) take part in cardioprotective signaling pathway inducted by chronic hypoxia. The high level of ROS must be precisely regulated by antioxidative system of a cell. The aim of diploma thesis was to examine the effect of intermittent hypobaric hypoxia (IHH, 7 000 m) on relative amount of antioxidative enzymes (peroxiredoxin 6 - PRX6, thioredoxin 1 and 2 - TRX1 and TRX2, thioredoxin reductase 1 - TRXR1) and also enzymes of iron metabolism (heme oxygenase 1 and 2 - HO1 and HO2, aconitase 1 and 2 - ACO1 and ACO2), which participate in regulation of cell redox state. Moreover, we studied the effect of adaptation to IHH and an antioxidant tempol on relative amount of calcium-independent phospholipase A2 (iPLA2). iPLA2 can remove peroxidized fatty acids from membrane phospholipids. On the other hand, iPLA2 can damage cell in I/R conditions. All enzymes were studied in homogenates from normoxic and IHH adapted rat left ventricular myocardium by Western blot. Adaptation to IHH caused a decrease of PRX6 and on the opposite an increase of...
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Antioxidative enzymes in heart
Kletečková, Lenka ; Hloušková, Patricie (advisor) ; Rychlíková, Jana (referee)
Cardiovascular diseases are one of the most frequently causes of morbidity and mortality in developed countries. An increase of oxidative stress is implicated by progression of heart diseases. Antioxidative enzymes protect the organism against them. The superoxide dismutases, the peroxiredoxins, the glutathione peroxidases and the catalase are advised to be used as the main antioxidative enzymes. The review is focused on the role of these antioxidative enzymes in the cardiovascular system. Antioxidative enzymes prevent the lipoperoxidation of biological membranes, the proteins inactivation, the DNA mutation and the apoptosis. It is well-known, that antioxidative enzymes positively influence a homeostasis of the vascular endothelium, prevent a burst of the cardiovascular disease and they are important for physiological functions, the morphology and the contractility of heart. The effect of antioxidative enzymes on the cardiovascular system is very complicated process and it still has not clarified all aspects of their action. A reseach of these enzymes is essential for understading the mechanisms of pathophysiological changes, which proceed into the cardiovascular system during the atherosclerosis, the myocardial infarction, the ischemic- reperfusion injury of the tissue and the calcification and...
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