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Utilization of physico-chemical analysis in study on cellular water
Matejčíková, Eva ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
The bachelor´s thesis deals with the study of methods, available at the Faculty of Chemistry at Brno University of Technology, that can be used to determine physical and chemical properties of cell water. The main task of this work was to specify which of these methods are suitable to determine physical and chemical properties of water in the cell and the properties of water occuring close to the cell surface. Based on the background research the series of experiments were proposed and implemented. Subsequently, this work deals with the optimisation of methods that were defined as the applicable techniques to determine the properties of cell water.
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Optimalization of techniques of microrheology for characterization of biopolymer hydrogels
Dušenková, Alica ; Smilek, Jiří (referee) ; Sedláček, Petr (advisor)
The main aim of the bachelor thesis is optimalization of microrheological techniques for characterization of biopolymer hydrogels. Hydrogels, based on thermoreversible biopolymer agarose, were selected for these experiments. The influence of incorporated poly(sodium 4-styrenesulfonate) on structure and viscoelastic properties of agarose hydrogels was investigated through diffusion coefficient and MSD curves. Microrheological properties were studied by fluorescence correlation spectroscopy, by using fluorescent beads, which were embedded in hydrogel systems.
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Preparation of humic hydrogels for appliaction in cosmetics
Pavlicová, Renata ; Mravec, Filip (referee) ; Sedláček, Petr (advisor)
This bachelor´s thesis is focused on the preparation and characterization of hydrogels containing humic substances and assessment of their potential usefulness in cosmetic practice. Main objective of the work was to develop a literature review focusing on the potential use of humic substances in the cosmetics and pharmaceutical industries. Furthermore, the aim was to prepare model hydrogels addition of soluble humic substances in traditional cosmetic compositions and their characterization by basic methods of analysis parameters. The main investigated parameters were consistency resulting gels (assessed subjectively and subsequently by rheology), their internal pH and dry matter. The experimental results showed that incorporation of humic substances into hydrogels resulting gels acceptable characteristics for further use in cosmetic applications.
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Swelling behavior and bioactivity of humic acids hydrogels
Kozelková, Aneta ; Hynšt, Jaroslav (referee) ; Sedláček, Petr (advisor)
This thesis deals with the study of the biological activity of humic substances. Based on the literature review preparation procedures were optimized in order to develop new hydrogel forms containing humic substances and biopolymers with high swelling capacity. Besides methodology for the rapid assessment of the biological activity obtained in laboratory conditions were designed and tested. The experimental part focused on characterization of hydrogel samples by means of routine physico-chemical methods, the main attention was paid to sorption of water and release of humic substances into solution. Then the prepared hydrogel materials were tested focusing on the growth effects on the maize. The absorption of mineral nutrients by the roots of plants were studied as well. The motivation of this work comes from the potential of agricultural and environmental applications of such hydrogel materials resulting in a renewal of previously exhausted organic content of soils and consequent interruption of substantial soil degradation.
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Carbon sorbents for biologically active substances
Lanžhotská, Aneta ; Sedláček, Petr (referee) ; Pekař, Miloslav (advisor)
This Bachelor thesis deals with the general characteristics of lignite and its definitions as a material system. Lignite represents geologically the youngest type of coal, and belongs to kaustobiolites, which are masses with varying degrees of carbonification of the original phytomass. The degree of carbonification is roughly between peat and brown coal. Particular attention was paid to the application of lignite as a cheaper and more versatile sorbent to replace activated carbon and for the use of sorption of biologically active substances in biotechnology. The specific structure and composition give the lignite the natural sorption capability. In model experiments, polyphenols were used as significant microbial inhibitors for which lignite had a high sorption and for glucose, which lignite practically did not absorb. A model experiment was carried out with a hydrolyzate of a corn biomass, where the lignite showed optimal sorption.
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Study of decomposition of organic matter in soil using the method of "tea bags"
Lišková, Kateřina ; Sedláček, Petr (referee) ; Enev, Vojtěch (advisor)
The main aim of this master thesis was to introduce an optimal method which could be used for study of a decompostion of an organic matter in a soil. For this purpose was chosen based on a literaly review so-called tea bag method. With regard to the completeness of the work, a physico-chemical characterization of the soil environment and HS isolated from it was also performed. The degraded organic material was then further characterized using thermogravimetric analysis, elemental analysis, FT-IR spectroscopy, and the total content of water-extractable polyphenolic substances in the samples was also determined.
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Analytical methods for qualitative and quantitative determination of PHA in cyanobacteria
Černayová, Diana ; Samek, Ota (referee) ; Sedláček, Petr (advisor)
The diploma thesis is confused to verify the applicability of selected physicochemical and spectroscopic methods for characterization of cyanobacteria, with special emphasis on possibilities of qualitative and quantitative analysis of polyhydroxyalkanoates (specifically polyhydroxybutyrate (PHB)) accumulated in cyanobacterial cells. The sample basis of the work was formed by cultures of cyanobacterial strains of Synechocystis sp. PCC 6803 and Synechocystis salina CCALA 192. The cultures were were cultivated in several ways to cover the widest possible range of physiological conditions and PHB contents, in particular using an autotrophic way of cultivation on shakers and multicultural culture method in a basic culture medium,and in media enriched with 2% salt (NaCl ) as well as mixotrophic culture media with different types of the carbon substrate. After few weeks of cultivation, cyanobacterial cultures were obtained and complexly analyzed by following techniques- cell suspensions were analyzed by flow cytometry and UV-VIS spectrometry (transmission and diffusion transmission mode), dry cell biomass was characterised by gas chromatography to obtain a exact amount of PHB, and then FT-IR spectrometry and thermogravimetric analysis. The work aimed to assess whether any of these methods can be a quick and affordable alternative to the determination of PHB content to the most commonly used method of gas chromatography, but also to assess what additional information about the physiological state of cyanobacterial cells can provide test methods. The highest correlation on PHB content was determined for the parameters determined by infrared spectroscopy, in which specific peaks from the characteristic wavelengths for polyhydroxybutyrate were important. Weak correlations on PHB content were achieved in thermogravimetric analysis and cytometry, using the hydrophobic fluorescent probe BODIPY 439/503, which bound to lipophilic parts of cells. In addition to the determination of PHB, it was possible to determine pigments present in cyanobacteria (such as chlorophyll, phycocyanin and carotenoids) by flow cytometry and UV-VIS diffusion transmission spectrometry. In the end, results from all used techniques were compared by PCA analysis to determine the similarity of all analyzed samples.
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Study on structure and behavior of water in vicinity of hydrophilic surfaces
Slaninová, Eva ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
The main aim of the bachelor thesis was focused on study of the effect of hydrophilic surfaces on the structure and behavior of water. Especially, it deals with the new experimental findings with regard to the anomaly behavior of water in vicinity of hydrophilic surfaces where explore the formation of structured water in as it is called exclusion zones. Exclusion zones were studied along the hydrophilic surfaces (Nafion) and examined from the point of view of the kinetics of exclusion zone, the effect of addition of ions and polar compounds and study the structure of the hydrated Nafion using infrared spectroscopy.
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Study on reactivity of humic acids via method of diffusion cells
Hrubá, Pavla ; Weidlich,, Tomáš (referee) ; Sedláček, Petr (advisor)
The diploma thesis focuses on utilization of diffusion cells in reactivity mapping study on humic acids. In the experimental part, samples 6 humic acids of different origin or chemical modification were studied. All the samples were characterized by basic analytical and physico-chemical methods (elemental analysis, thermogravimetry, determination of acidity, spectrometry). Methylene blue was utilized as a model reactive probe and agarose gel as an inert support medium. An effect of interactions between humic acids and methylene blue on diffusivity of the dye in the hydrogel was determined and discussed.
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Utilization of physicochemical and spectroscopic techniques in study of stress-response of cyanobacteria
Skoryk, Maksym ; Šedrlová, Zuzana (referee) ; Sedláček, Petr (advisor)
Tato bakalářská práce je soustředěná na zkoumaní cyanobakterií, vystavených hyper a hyposmotickým stresům. Na základě literární rešerše byly navžené vhodné analytické metody určené ke studiu dvou modelových organismu - Synechocystis sp. PCC 6803 a Synechocystis sp. salina Wislouch CCALA 192. Celkem čtyři metody byly použité k charakterizaci osmoticky zatížených bakterií. Průtoková cytometrie byla použita k vyhodnocení viability. Fluorescenční sonda SYTOX Blue poskytla důvěryhodnou informaci ohledně viability bakterií. Propidium jodid naopak poskytl nezřetelnou informaci. Optické vlastnosti cyanobakterií byly prozkoumané pomoci UV-VIS absorpčních a turbidimetrických měření. Termogravimetrická analýza byla použita pro mapování změn obsahu vody v osmoticky stresovaných buňkách. Tato metoda ukazala. že PHB-positivní Synechocystis sp. PCC 6803 jsou pravděpodobně vice odolné vůči hyperosmotickým stresům než PHB-negativní. Plynová chromatografie byla použita ke kvantifikaci vnitrobuněčného PHB, který činil přibližně 1-2 % suché hmoty PHB-positivních buněk.
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