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Study of mechanisms of ammonia production in yeast colonies and liquid cultures
Strachotová, Dita ; Váchová, Libuše (advisor) ; Sychrová, Hana (referee) ; Gášková, Dana (referee)
Yeast, although non-motile and unicellular organisms can create organized structures, colonies, in which cells communicate and cooperate and which in some ways resemble multicellular organisms. Our previous studies on yeast colony development revealed that colonies periodically change pH of their surroundings. Alkalization of an agar medium is accompanied by production of volatile ammonia that acts as the long-range signal. Microarray analysis of the expression changes in Saccharomyces cerevisiae colonies during their transition from acid to alkali phase revealed significant changes in yeast transcriptome. Among others, strong induction of expression of three homologous genes ATO1 (YNR010c, ADY2), ATO2 (YNR002c, FUN34) and ATO3 (YDR384c) at the beginning of the alkali phase was found. These genes encode membrane proteins that may function as ammonium/H+ antiporters. This work contributes to better understanding of both the ammonia signaling and the role of putative ammonium exporters - Ato proteins. It was revealed, that other volatile compounds - methylamine and propylamine - are (in addition to ammonia) able to induce entry into the alkali phase of yeast colony development. Moreover, the significant impact of the transport of monocarboxylic acids on ammonia production and yeast colony development...
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Modular Synthesis of Steroids by Negishi Reagent
Herrmann, Pavel
1 Introduction This dissertation is focused on the development of new methodology for the synthesis steroid derivatives. Steroids, due to their biological activity, still represent a favourite target of total syntheses. Many approaches for their preparation, based on transition metal-mediated or catalyzed reactions, have been developed. From the synthetic point of view, it would be ideal or at least highly desirable and interesting to develop a methodology based on the repetitive use of one reagent. Fortunately, such a strategy has not been published yet. To bring this methodology to life, it is crucial to use a suitable reagent that can selectively react with a wide variety of functional groups. In this regard, zirconocene derivatives seem to be potentially applicable as they display a broad reactivity. Hence, the main objective of this work is to elucidate the viability of their sequential use in the synthesis of complex natural compounds. 2. Aim of the Work The aim of this work is to develop a new synthetic methodology for the preparation of polycyclic isoprenoids. This methodology should be based on the sequential repetitive use of one reagent and should enable modular and flexible access to a wide variety of compounds. The appropriate reagent should function as a universal tool. Bearing the broad...
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Preparation of 6-Aryl- and 6-Heteroarylpurines by [2+2+2]-Cyclotrimerizations
Turek, Pavel
Preparation of 6-Aryl- and 6-Heteroarylpurines by [2+2+2]- Cyclotrimerizations Mgr. Pavel Turek Dept. of Organic and Nuclear Chemistry, Faculty of Science, Charles University Prague 2009 The aim of my project was to synthesize new potentially biologically active arylpurines by transition metal catalyzed or mediated [2+2+2]-cyclotrimerization reactions. This approach should enable to assemble various structural motives attached to the purine skeleton. The main targets were 6-arylpurines. 6-Arylpurine derivatives have diverse types of a biological activity: some substituted 6-arylpurine bases are antagonists of corticotropin-releasing hormone or possess antimycobacterial and antibacterial activity, while 6-arylpurine ribonucleosides are potent cytostatics. These facts explain, why it is worth being interested in synthesis of this class of compounds. Until now 6-arylpurines have been mostly prepared by cross-coupling reactions of 6- halopurines with various organometallic compounds, but this approach is limited by factors like availability, reactivity and stability of the corresponding arylmetals. The synthetic strategy used in my project was based on a transition metal catalyzed or mediated cyclotrimerization of alkynes. Generally, these methods enable to assemble aromatic and heteroaromatic compounds from...
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Study of Cobaltites and Manganites by NMR and EXAFS
Procházka, Vít ; Štěpánková, Helena (advisor) ; Novák, Pavel (referee) ; Figiel, Henryk (referee)
This Thesis is devoted to a study of physical properties of manganites and cobaltites with perovskite structure. Combination of macroscopic (magnetization measurements and X-ray powder diraction) and microscopic (NMR and EXAFS) methods was applied in order to get a complex and detailed view on the charge and magnetic ordering of transition metals ions in the LaMn1xCoxO3 solid solutions. The Thesis presents new results which were published in international journals. The main result is the determination of details of Mn and Co local environments and the spin arrangement of their individual oxidation states in the ferrimagnetic structure of the compounds studied.
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Fungal genetics, genome evolution and use of flow cytometry in study of DNA
Würtherlová, Tereza ; Kostovčík, Martin (referee) ; Kolařík, Miroslav (advisor)
The fungal genome is a dynamically changing structure. By its remodelling, the organism can respond to the environmental changes and develop itself. The genome expansion is often accompanied by transition to parasitic or mutualistic way of life. The genome expansion can be caused by the multiplication of some chromosomes (aneuploidisation), the whole genome duplication (polyploidisation) or the spreading of repetitive sequences. The impact of genome size to the ecology and life strategy of the organisms is more and more studied in recent years. In mycology, nevertheless, it escapes sufficient attention. The flow cytometry (FCM) is a modern and progressively developing method that enables to determine the genome size and estimate CG/AT base ratio. The combination of FCM with knowledge of the fungal ecology and forces that form the genome enable to discover a general trends of the evolutionary processes. My study summarises knowledge about the processes leading to changes in the size/structure of the fungal genome, the correlations with genome size and presents the principle of flow cytometry and its application in mycology.
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Cyclization Reactions Mediated by Transition Metals
Matoušová, Eliška ; Pour, Milan (advisor) ; Bureš, Filip (referee) ; Šrogl, Jiří (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of inorganic and organic chemistry Candidate: Mgr. Eliška Matoušová Supervisor: prof. RNDr. Milan Pour, PhD. Title of Doctoral Thesis: Cyclization reactions mediated by transition metals Within the framework of this Thesis, several analogues of naturally occurring biologically active pyranones were prepared. The synthetic procedure was based on a Pd-cata- lyzed carbopalladation of enyne precursors with subsequent lactonization. Employing this method, bicyclic pentenolides containing fused nitrogen heterocycle as well as carbocycle were synthesized. The preparation of the corresponding oxygen-containing derivative was not successful. The compounds were tested for their antifungal, anitibacterial and cytostatic activity. The second part of the Thesis deals with synthesis of furans and dihydropyrans via palladium and gold catalysis. A highly efficient method for AuI -catalyzed cyclization of propargyl vinyl ethers to dihydropyrans was developed using tris(2-furyl)phosphine as a ligand and methanol as a nucleophile. This method was employed for the preparation of 15 dihydropyran derivatives in high yields. In the absence of a nucleophile furans were formed in lower yields. Dihydropyrans undergo an as yet undescribed...
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Education in inorganic chemistry in the context of common life
Matoušková, Šárka ; Čtrnáctová, Hana (advisor) ; Vojtíšek, Pavel (referee) ; Klečková, Marta (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Science Department of Teaching& Didactics of Chemistry Ph.D. study program: Chemistry Education Education in Inorganic Chemistry in Context of Common Life Ph. D. thesis Mgr. Šárka Matoušková Abstract The objective of this Ph.D. thesis is to contribute to the effectiveness and quality of education of inorganic chemistry in the context of common life. The first chapter characterizes the current state of inorganic chemistry as a science and as a teaching subject. The requirements of the teachers teaching inorganic chemistry in secondary schools were determined by using the method of personal interview in the second chapter. After comparing the school systems in the third chapter and the analysis of selected textbooks used in the Czech Republic and in one of the countries of Germany, the criteria for creating teaching materials for inorganic chemistry were set. A textbook on the topic of the transition metals for secondary school pupils was created by means of a transformation of a scientific text. Finally, the textbook was evaluated by chemistry teachers at secondary schools in the form of a questionnaire survey and adjusted to the final form. Keywords: school system, secondary school, inorganic chemistry, chemistry education, textbook, transition metals, interview,...
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Ab initio study of {101-2} twinning transition in magnesium
Káňa, Tomáš ; Ostapovets, Andriy
Twinning is an important deformation mode in materials with the hexagonal close-packed (hcp) structures. The shear deformation combined with shuffling of atomic planes can lead to a transition between the Mg hcp structure and a twinned hcp structure. Studying such a transition by means of ab initio methods should bring more insight into the twinning mechanism in magnesium where the {1012} planes are the twinning planes. Comparison of ab initio results with those obtained using the semi-empirical embedded atom method is provided. It can help improve the fitted parameters of the embedded atom method.
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