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Chemistry of polynitro heterocyclic compounds
Kubátková, Nela ; Bednařík, Karel (referee) ; Friedl, Zdeněk (advisor)
The review of polynitro heterocyclic compounds was written. These are substances with ability to detonate, which is caused mainly by presence of nitrogroups, which are bonded to carbon atoms in their cycles. The thesis deals with common polynitro five-membered heterocycles with one nitro atom, up to six-membered heterocycles with three nitrogen atoms. There are processed basic information of these compounds, as well as their physical-chemical properties and properties of detonation, the possibility of their preparation, which are displayed in the form of chemical reactions.
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Antioxidant system of tomato plants exposed to triazole fungicides
Žufić, Antoniana ; Hýsková, Veronika (advisor) ; Jaklová Dytrtová, Jana (referee)
Fungal pathogens cause severe crop losses worldwide. Recently, however, chemical fungicides have become dangerous environmental contaminants affecting non-target organisms. The aim of this study was to investigate the effect of triazole fungicides in the form of penconazole (P), tebuconazole (T) or their combination (PT) on tomato plants Solanum lycopersicum L. cv. Cherrola. No significant change in the activity of a key enzyme of the ascorbate-glutathione cycle, ascorbate peroxidase and activity of cytosolic peroxides, was detected in leaves, roots or fruits at the intervals studied, i.e. after two and five weekly treatments of P, T or PT, either as a foliar or a soil application. While slightly increased guaiacol peroxidase activity was found in roots due to T spraying and PT combination, the activity of this enzyme was reduced in leaves similar to catalase. The greatest changes in leaf antioxidant capacity correlated with increased phenolic and flavonoid content were observed after five treatments of penconazole (P) as a soil application both P alone and in combination as PT. The studied triazoles significantly affected the abundance of isoforms of superoxide dismutase and partially total peroxides in leaves, roots and fruits and of acorbate peroxidase in leaves. The highest content of HSP70 was found in...
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Use of biochemical methods in the study of plant metabolism with emphasis on the defense system
Bělonožníková, Kateřina ; Ryšlavá, Helena (advisor) ; Luhová, Lenka (referee) ; Plchová, Helena (referee)
As sessile organisms, plants cannot avoid being exposed to various biotic and abiotic stress factors. To defend themselves plants have developed complex and sophisticated defense mechanisms. In agriculture, pesticides are used for plant protection, but they can have undesirable side effects, and therefore attention is being paid to biological control agents. One such agent is Pythium oligandrum, a soil oomycete that has a positive effect on plants at several levels. On the one hand, it secretes elicitins, which stimulate defensive responses and prepare the plant for possible infection (i.e., priming effect), and on the other hand, it produces tryptamine, a precursor of auxin, thus supporting the plant's growth. Furthermore, P. oligandrum directly acts as pathogen mycoparasite or evokes antibiosis, or competition for nutrients and space with other microorganisms. The key research topic of this thesis was the analysis of the biochemical properties of eleven Pythium strains and their impact on plant metabolism. Our results showed that even closely related P. oligandrum strains significantly differ in the content of compounds secreted into the medium, including proteins, amino acids, tryptamine, and hydrolytic enzymes capable of degrading cell walls (endo-β-1,3-glucanase, chitinase, and cellulase),...
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Utilization of N-fluoroalkyl-1,2,3-triazoles in organic synthesis
Markos, Athanasios ; Beier, Petr (advisor) ; Veselý, Jan (referee) ; Hanusek, Jiří (referee)
Athanasios Markos Abstract This Thesis deals with denitrogenative transformations of N-fluoroalkyl-1,2,3-triazoles, easily available heterocycles via copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) of safe and stable N-fluoroalkyl azides and alkynes. The introductory chapter describes general approaches towards N1-substituted 1,2,3- triazoles, methods of N1-,-difluoroalkyl-1,2,3-triazoles preparation and both, transition metal-catalyzed and transition metal-free transformations of N1-substituted 1,2,3- triazoles. In the first part of the Thesis, rhodium-catalyzed reactions of N-fluoroalkyl-1,2,3-triazoles are described. Rhodium-catalyzed reactions of N-fluoroalkyl-1,2,3-triazoles in presence of suitable reagents provide access to five-membered N-fluoroalkyl heterocycles, 2- fluoroalkyl oxazoles and ketamides. In the second part of the Thesis, both Brønsted and Lewis acid-mediated transformations of N-fluoroalkyl-1,2,3-triazoles leading to stereodefined N-alkenyl compounds, such as enamides, enimines, amidines and other are discussed. The robustness of the method is showcased on gram scale syntheses and preparation of a drug analogue. At last, thermally-induced rearrangement of N-fluoroalkyl-1,2,3-triazoles to 3-fluoroalkyl-2H- azirines and the proposed mechanism of the reaction are described.
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Use of biochemical methods in the study of plant metabolism with emphasis on the defense system
Bělonožníková, Kateřina
As sessile organisms, plants cannot avoid being exposed to various biotic and abiotic stress factors. To defend themselves plants have developed complex and sophisticated defense mechanisms. In agriculture, pesticides are used for plant protection, but they can have undesirable side effects, and therefore attention is being paid to biological control agents. One such agent is Pythium oligandrum, a soil oomycete that has a positive effect on plants at several levels. On the one hand, it secretes elicitins, which stimulate defensive responses and prepare the plant for possible infection (i.e., priming effect), and on the other hand, it produces tryptamine, a precursor of auxin, thus supporting the plant's growth. Furthermore, P. oligandrum directly acts as pathogen mycoparasite or evokes antibiosis, or competition for nutrients and space with other microorganisms. The key research topic of this thesis was the analysis of the biochemical properties of eleven Pythium strains and their impact on plant metabolism. Our results showed that even closely related P. oligandrum strains significantly differ in the content of compounds secreted into the medium, including proteins, amino acids, tryptamine, and hydrolytic enzymes capable of degrading cell walls (endo-β-1,3-glucanase, chitinase, and cellulase),...
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Copper complexes with triazoles
Jaklová Dytrtová, Jana ; Jakl, M.
Triazoles are artificial chemicals used as fungicides as well as for pharmaceutical treatment. However, their reactivity is highly influenced by the presence of other chemicals. Especially, the presence of copper cations changes the reactivity of triazole by theoretically unexpected way. We have studied the interactions of the triazole ring with copper cations to help explain the reactivity of triazoles as a group.
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Tebuconazole and its behaviour in the presence of magnesium
Jakl, M. ; Jaklová Dytrtová, Jana
Tebuconazole is a fungicide frequently used in agriculture. Its possible impact to (non-)target species is influenced by its presence. Moreover, the presence of triazoles in soil has an impact to bioavailability of nutrients. This study brings the information potentially useful in the evaluation of tebuconazole fate in the environment. The studies based on the electrospray gas phase experiments provide an estimation of the tebuconazole ability to create complexes with magnesium.
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Penconazole and its behaviour in the presence of copper
Jakl, M. ; Jaklová Dytrtová, Jana
Penconazole is a fungicide frequently used in agriculture. Its possible impact to (non-)target species is influenced by its interactions e.g. with copper, typically present in soil as an ion (or in week complexes) or in bodies, as a part of enzymes. This study brings the information potentially useful in the evaluation of penconazole fate in the environment. The studies based on the electrospray gas phase experiments provide an estimate of the penconazole reactivity in copper presence including its possible degradation pathways.
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Chemistry of polynitro heterocyclic compounds
Kubátková, Nela ; Bednařík, Karel (referee) ; Friedl, Zdeněk (advisor)
The review of polynitro heterocyclic compounds was written. These are substances with ability to detonate, which is caused mainly by presence of nitrogroups, which are bonded to carbon atoms in their cycles. The thesis deals with common polynitro five-membered heterocycles with one nitro atom, up to six-membered heterocycles with three nitrogen atoms. There are processed basic information of these compounds, as well as their physical-chemical properties and properties of detonation, the possibility of their preparation, which are displayed in the form of chemical reactions.
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