National Repository of Grey Literature 56 records found  beginprevious31 - 40nextend  jump to record: Search took 0.01 seconds. 
The role of trehalose in mycorrhizal associations
Šoch, Jan ; Ponert, Jan (advisor) ; Hála, Michal (referee)
Mycorrhizal symbiosis is a widely spread phenomenon in nature. A translocation of nutrients occurs between symbionts with disaccharide trehalose playing a key role in the process. However, this saccharide fulfils many important roles in metabolism of fungi and plants. Fungi use trehalose mainly as storage and transport saccharide. On the other hand, trehalose occurs in extremely low amounts in plants where it acts as a signal molecule. Thus it is likely that the saccharide could be used by the fungus to manipulate plant metabolism on a physical interface between symbionts. Trehalose has a similar function in many parasitic interactions. In most cases of mycorrhizal associations trehalose synthesis creates a carbon sink in mycelium which leads to saccharide transfer from the host plant to the fungus. Completely different situation occurs in the types of mycorrhizal symbiosis, where saccharides are translocated from a fungus to a plant. Some plants can utilize trehalose effectively as a sole source of energy. Consequently, the question raises - could such plants gain fungal trehalose on purpose as a source of energy and carbon? This review aims to assess and discuss the mentioned possibilities considering available literature. Key words: mycorrhiza, orchids, parazitism, saccharides, sink, symbiosis,...
Fast Dynamic Processes in Solution Studied by NMR
Šoltésová, Mária
Title: Fast Dynamic Processes in Solution Studied by NMR Spectroscopy Author: Mária Šoltésová Department: Department of low temperature physics, Charles University in Prague, and Department of Materials and Environmental Chemistry, Stockholm University Supervisor: doc. RNDr. Jan Lang, Ph.D., Department of low temperature physics, Charles University in Prague, and Prof. Jozef Kowalewski, Department of Materials and Environmental Chemistry, Stockholm University Abstract: Nuclear magnetic resonance (NMR) spectroscopy is capable to deliver a detailed information about the dynamics on molecular level in a wide range of time scales, especially if accompanied by suitably chosen theoretical tools. In this work, we employed a set of high-resolution NMR techniques to investigate dynamics processes in several weakly interacting molecular systems in solution. Van der Waals interactions play an important role in inclusion complexes of crypto- phane-C with chloroform or dichloromethane. The complex formation was thoroughly investigated by means of 1H and 13C NMR experiments along with the quantum- chemical density functional theory (DFT) calculations. We characterized kinetics, thermodynamics, as well as fine details of structural rearrangements of the complex formation. Internal dynamics of oligo- and...
Fast Dynamic Processes in Solution Studied by NMR
Šoltésová, Mária ; Lang, Jan (advisor) ; Mäler, Lena (referee) ; Batta, Gyula (referee)
Title: Fast Dynamic Processes in Solution Studied by NMR Spectroscopy Author: Mária Šoltésová Department: Department of low temperature physics, Charles University in Prague, and Department of Materials and Environmental Chemistry, Stockholm University Supervisor: doc. RNDr. Jan Lang, Ph.D., Department of low temperature physics, Charles University in Prague, and Prof. Jozef Kowalewski, Department of Materials and Environmental Chemistry, Stockholm University Abstract: Nuclear magnetic resonance (NMR) spectroscopy is capable to deliver a detailed information about the dynamics on molecular level in a wide range of time scales, especially if accompanied by suitably chosen theoretical tools. In this work, we employed a set of high-resolution NMR techniques to investigate dynamics processes in several weakly interacting molecular systems in solution. Van der Waals interactions play an important role in inclusion complexes of crypto- phane-C with chloroform or dichloromethane. The complex formation was thoroughly investigated by means of 1H and 13C NMR experiments along with the quantum- chemical density functional theory (DFT) calculations. We characterized kinetics, thermodynamics, as well as fine details of structural rearrangements of the complex formation. Internal dynamics of oligo- and...
Use and effectiveness of activation methods in chemistry education
Pražienka, Miroslav ; Šulcová, Renata (advisor) ; Teplá, Milada (referee)
CHARLES UNIVERSITY IN PRAGUE - Faculty of Science Department of Teaching and Didactics of Chemistry Albertov 3, 128 40 Praha 2, Czech Republic Use and effectiveness of activation methods in chemistry education Bc. Miroslav Pražienka mprazienka@seznam.cz Executed pedagogical survey reflects the requirements of modern pedagogy and didactics - the teacher should have a new approach to teaching, both from a technical standpoint, both in the methods. At present, preparation of future teachers, but also in lifelong adult education teachers, computers are preferred, modern electronics (and everything associated with them) and such methods, where the pupil is actively involved in teaching and not just a passive "recipient". For the purposes of my thesis was, therefore, a wide range of teaching aids (PowerPoint presentations, worksheets, educational teaching games, demonstration experiments, tests, including methodologies and manuals), through which pupils were taught. Before and after instruction was given them knowledge and skills test, which was then evaluated. They were also sampled pupils from other primary schools and the results were compared. At the beginning of the survey were established two hypotheses (knowledge and skills gradually decreases with increasing time from the subject and taught for a...
Electrophoretic separations of saccharides in short capillary.
Vochyánová, Blanka ; Opekar, František (advisor) ; Jelínek, Ivan (referee)
A new laboratory system has been developed for rapid electrophoretic separations and determinations of inorganic and organic ions. The instrument employs short fused silica capillary in combination with contactless conductivity detection. The basic functions of the apparatus have been tested using mixture of inorganic ions. It has further been applied to separations of neutral mono- and disaccharides. The model mixture contains five saccharides (sucrose, lactose, glucose, fructose and ribose). The technique developed has been used to determine sucrose, glucose and fructose in high-energy drinks.
Separation and determination of possible products of enzymatic cleavage of 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside using capillary electrophoresis
Velvarská, Romana ; Křížek, Tomáš (advisor) ; Kalíková, Květa (referee)
This work deals with the development and optimization of conditions of a method that can be used to compare the activity of the enzyme β-N-acetylhexosaminidase in hydrolysis of a natural substrate and a chromogenic substrate, which is often used in the study of enzyme kinetics. As a substrate, 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside was selected for cleavage. This oligosaccharide contains bond, which the enzyme cleaves in the natural substrate, and the bond that occurs in the chromogenic substrate. To determine the products arising from enzymatic hydrolysis of 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside, capillary zone electrophoresis was used. First, it was necessary to find the optimal composition of the electrolyte, its pH and concentration. The optimal background electrolyte was a solution of sodium tetraborate at a concentration of 25 mmol/l and a pH of 10.25. Subsequently, repeatability, calibration curves and linearity, limit of detection and limit of quantification were investigated. Repeatability of migration times ranged up to 0.6%, the repeatability of peak areas between 2.5 and 6.3%. Limits of detection were ranging from 0.005 to 0.120 mmol/l. Finally, the optimized method was successfully used to monitor the actual enzyme cleavage.
Educational Project Saccharides Topic Work in Chemistry for high school
Šedivá, Renata ; Šulcová, Renata (advisor) ; Součková, Danuše (referee)
Charles University in Prague - Faculty of Science Department of Teaching and Didactics of Chemistry Albertov 3, 128 40 Praha 2, Czech Republic Educational project Saccharides Topic Work in Chemistry for high School Bc. Renata Šedivá sedivarenata@gmail.com This diploma thesis is a suggestion of educational project Saccharides classifiable into education of Chemistry in 3rd year of four-year grammar school. In the first part there is a research of literature sources concerning the issue project education. The Following part is a suggestion of educational project Saccharides, its product are lessons about the topic saccharides, which are designed, prepared and taught by the students. The suggestion of the project contains a timetable of the project, instructions and methodology for individual parts of the project (motivation, preparation of lessons, laboratory works, presentation of lessons, final practice, test and reflection), methodological notes and documentation to the implementation of the project at Grammar school in Dvůr Králové nad Labem.
Determination of macroelements, organic acids and other parameters in ketchups
Popelová, Nikola ; Divišová, Radka (referee) ; Diviš, Pavel (advisor)
The aim of this master’s thesis is perform basic analyses of samples ketchups. The theoretical part describes the basic characteristics of tomato, tomatoes processing and production of puree and ketchup. Then there are described analytical methods which were used for analysing the selected parameters in ketchups. The experimental part deals with the determination of pH, total solids, organic acids, saccharides, macroelements and lycopene in ketchups. Citrate and acetate were analysed by IC. The amount of acetate in ketchups was about 5 times greater than the amount of citrate. Glucose, fructose and sucrose were analysed by HPLC. Glucose and fructose were determined in all samples but sucrose not. The ICP-OES method was used to determine four elements. Magnesium was the least represented element and sodium was the most represented element in the analysis. The amount of sodium was recalculated on the amount of salt. Lycopene was analysed by UV-VIS spectrometry. Its amount in ketchups is influenced by the variety of used tomatoes and plenty of other factors.
Evaluation of Physical and Chemical Parameters of Still Less Exploited Species of Small Fruit and Proposal of a New Soft Drink from this Fruit
Cetkovská, Jitka ; Krška,, Boris (referee) ; Barták,, Petr (referee) ; Omelková, Jiřina (advisor)
This thesis deals with still less expolited species of small fruit, evaluation of its physical and chemical parameters and proposal of a new soft drink from one of the studied species of furit. Firstly, for the characterisation of basic nutrition parameters (dry matter, content of organic acids and saccharides) and biologicaly active substances (vitamin C, anthocyanins and phenolic compounds) suitable titration, spectrophotometric, chromatographic and electrophoretic methods were chosen, optimized and validated. The sample preparation procedure was optimized as well. For three years (2010–2012) the content of listed parameters was monitored in some cultivars of five species of small fruit: in seven cultivars of sea buckthorn, in ten cultivars of cornelian cherry, in twelve cultivars of rowanberry, in two cultivars of chokeberry and in seventeen cultivars of elderberry. By means of Duncan’s test, analysis of principal components (PCA) and cluster analysis (CLU) the main differences between studied cultivars were observed mainly in sea buckthorn and rowanberry, where single cultivars were easily distinguishable from others on the basis of genetic origin. On the basis of comparison of determined parameters in studied species of fruit and with collaboration with fruit processing company the suitable species of fruit for commercial utilization was chosen – elderberry, as a important source of anthocyanins and phenolic compounds. A new soft drink as a proposal of utilization of this fruit was created – fruit juice or nectar with portion of elderberry juice. Mixed juices and nectars with various composition were prepared from elderberry and grape juice and the sensory analysis of these drinks was performed. The best evaluated were 100% fruit juices prepared with 30–50% portion of elderberry juice. The composition was jurally protected. On the basis of this protection the product consisted from 100% fruit juice with 10% of elderberry component mixed with apple and grape juice was introduced to the market by the fruit processing company.
Determination of the basic physical and chemical parameters of fruit juice from aronia
Zídková, Anežka ; Jurečková, Zuzana (referee) ; Diviš, Pavel (advisor)
Theoretical part of bachelor´s thesis contains basic information about aronia (Aronia melanocarpa) and examples of their use. There is a description of analysed substances, which are contained in aronia berries, and their importance for human organism. Experimental part is focused on determination of minerals, saccharides and vitamin C in aronia juices, syrups, nectar and aronia wine. Elements were determined by inductively coupled plasma optical emission spectrometry. Liquid chromatography was chosen for analysis of saccharides and vitamin C. All of analysed products are significant sources of macroelements. The highest concentrations of elements were determined in the sample named Aroniový skorosirup, which was sugared by vaporized apple juice. Fructose and glucose were contained in all products. Sucrose was only in products which were sugared. The amount of vitamin C was lower in consequence of pasteurization and storage.

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