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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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Utilization of pesticides in the environment
Hamršmíd, Filip ; Jakl, Michal (advisor) ; Vítková, Martina (referee)
This thesis deals with the effects of triazole fungicides on plant growth and development and accessibility of nutrients from the soil, using case studies with the active substance penconazole (Penk).
For this work, it were established several objectives, which should create a comprehensive picture of the potential impact of Penk, triazole fungicide, on plants and soil. As the objectives of the work were determined as followings: find out (I) which affects the addition of Penk has to grow edible tomato (Solanum lycopersicum L.) yields and whether it has an effect on photosynthesis, (II) evaluate the effect of the addition of Penk to accessibility of nutrients in three different soil types, in fluvisols, modal cambisols and modal chernozem, during the incubation, and (III) to analyze the effect of different doses of Penk to changes in nutrient uptake examined soils.
Vegetation experiment (I) showed differences in the growth of the biomass tomato depending on the concentration of added Penk. In all soils were decreased nutrient intakes in proportion to the dose of Penk. When applying the higher dose of Penk modal chernozem had decreased nutrient intake over the control sample about half. Addition of lower and higher dose of Penk decreased yields of plants grown on the substrate fluvisols approximately by one third. It has been shown that the addition of Penk adversely affects the content of chlorophyll a and b, but has no significant effect on chlorophyll c. In the soil incubation experiment (II) it was found that in the range of 8 weeks Penk addition affects the accessibility of certain nutrients (micro- and macro-elements) of the soil for the plants, in all monitored soil types. However, it was also shown that after the fourth week of incubation the degradation with consequent increase in the proportion of acceptable nutrients was observed. This proves that Penk is not persistent in soils and its use is very likely safe in the long term. In the sorption of a short term experiment (III), it was observed from the viewpoint of physicochemical interactions estimate changes in nutrient uptake in selected soil improvers based Penk. This thesis showed that Penk has an impact on the accessibility of certain nutrients in the short term. The most significant effect was observed for the iron when its accessibility steeply decreased with increasing addition of Penk.
This thesis is trying to assess the behavior of Penk in the environment. They have demonstrated its effects on plant growth and development and the content elements in the above-ground parts and roots of Solanum lycopersicum L. and accessibility of nutrients from the soil in the short and long term.
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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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