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Plant defence against arsenic toxicity: a key role of arsenate reductase?
Jurčíková, Martina ; Mašková, Petra (advisor) ; Hála, Michal (referee)
Arsenic in its various forms is one of the most toxic environmental contaminants, which is also taken up by plants and can affect their vitality. The risk category is crops where As contamination reduces the overall yield and through which As enters the food chain. Its inorganic (arsenite and arsenate) and organic (methylated) forms are taken up by roots and rhizomes, where they can either accumulate or be translocated and subsequently stored in shoots. Arsenate reductase is an enzyme that catalyses the reduction of arsenate to arsenite, thereby affecting not only the overall toxicity of As in the plant, but also its transport between underground and aboveground organs. However, the interplay of the different mechanisms of As uptake, translocation and detoxification has not been investigated in detail. The aim of this bachelor thesis was to analyze and compare the importance of arsenate reductase in these processes in the model organism Arabidopsis thaliana, in a rice crop and in the arsenic hyperaccumulator Pteris vittata. The different tolerance of these organisms to As and their differences in the preferential site of As deposition in leaves or seeds could be used for different purposes, such as in the phytoremediation of As-contaminated soils, or in limiting the uptake or translocation of As to...
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Preparation and phytoextraction of 125-I labelled pharmaceuticals
Luptáková, Dominika ; Smrček, Stanislav (advisor) ; Soudek, Petr (referee)
Pharmaceuticals are group of organic substances with significant worldwide consumption in human and veterinary medicine. These compounds may be metabolized in the organism, but in some cases they remain unchanged and both are usually excreted via renal excretion in the native form or as metabolites. Large quantities of pharmaceuticals and their metabolites contaminate municipal wastewater. The wastewater treatment plants are unable to remove these substances completely, so they contaminate surface water, groundwater and soil as well. Due to the biological activity of pharmaceuticals, long - term effect may cause bacterial resistance, endocrine influence, DNA and renal damages in non-target organisms. The phytoextraction and the translocation of radiolabeled diclofenac with 125 I were experimentally studied by using of in vitro cultivated plants Helianthus annuus and Zea mays. Efficiency od phytoextraction was monitored as decrease of radioactivity of tested substance [125 I]diclofenac in Murashige-Skoog cultivation medium. Both species are able to extract tested substance during 8 to 10 days of cultivation, with efficiency approximately 85 % using Zea mays and 79 % using Helianthus annuus. Better extraction ability of diclofenac was observed at Helianthus annuus - 80 mg/ kg of dry weight compared...
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