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Utilization of novel strategies of alginate crosslinking in the development of next-generation bioinoculants
Gašparová, Dominika ; Pekař, Miloslav (oponent) ; Sedláček, Petr (vedoucí práce)
This master's thesis focuses on diverse alginate crosslinking strategies, aiming to advance the development of next-generation bioinoculants. Investigating various gelation strategies is applied to five commercially available alginates and isolated bacterial alginate. Experiments focused on alginate macrogel preparation assessed the occurrence and quality of crosslinking, which was analyzed by incorporating both amplitude and frequency testing methodologies. Selecting appropriate crosslinking agents and determining their concentrations were essential objectives. Crosslinking agents such as those containing zinc chloride, aluminum chloride, barium chloride, calcium sulphate and ferric chloride solution were evaluated, with all proving effective in both macro- and microencapsulation processes. Optimization efforts included studying crosslinking conditions, with favorable results observed at a temperature of 7°C and optimal crosslinking durations ranging from 30 to 120 minutes. Comparative analyses of six selected crosslinking agents revealed notable findings in gel swelling studies and mechanical property assessments via the squeeze test, thermogravimetric analysis and image analysis. Barium crosslinking demonstrated promising results in preserving water content during rehydration, while zinc-based crosslinking achieved the highest dry matter content. Image analysis unveiled smaller gel beads formed with aluminum and barium crosslinking agents, indicating their effectiveness. Microencapsulated gel beads, particularly those crosslinked with barium, showed potential due to their reduced size. The experiment's pinnacle was the bacterial culture's gelation, where aluminum and barium crosslinking solutions yielded the smallest particle sizes. Notably, barium crosslinking resulted in the smallest area and error bar, indicating its effectiveness.
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Self-encapsulation of Plant Growth Promoting Rhizobacteria as a way towards new generation of bioinoculants
Gašparová, Dominika ; Obruča, Stanislav (oponent) ; Sedláček, Petr (vedoucí práce)
This bachelor thesis focuses on Plant Growth-Promoting Rhizobacteria that can be used as a suitable ecological alternative to conventional fertilizers. However, most of today's approaches to incorporating PGPR into the process of soil fertilization are convoluted and costly. Crosslinking of alginate self-produced by PGPR offers a new possibility of plantgrowth- promoting bacteria encapsulation. The aim of this thesis consists of preparing gel matrices with incorporated bacteria, followed by testing the bacteria's viability and quantity. Firstly, experiments were carried out to determine various properties of gels produced by the chosen representative bacteria Azotobacter vinelandii. These properties include the molecular weight of alginate (with the highest molecular weight of strain CCM 289 (329,78± 6,8) kDa), the alginate's amount in the gel, the content of PHB (34%-44% CDW), and the gel's overall rheological properties. The complex modulus (as a representation of rheological properties) of the firmest gel reached the value of 13,34 kPa. The bacteria content was examined by flow cytometry, the CFU method, and spectrophotometry. The viability of bacteria was determined by analyzing the fluorescence intensity via fluorescent dyes (propidium iodide, fluorescein diacetate, rhodamine 123, calcein AM), then by using the CFU method, and also via the plate method. Furthermore, the effects of various factors such as different pH levels (pH 3, 7, and 10) or adding the specific alginatedegrading enzyme alginase were also examined. Releasing of the bacteria was observed over the course of seven days using flow cytometry and the CFU method. The plate method proved the bacteria's survival after gelation and without any source of carbon. The largest disintegration of gels occurred in acidic pH. Moreover, the effect of alginase on crosslinked bacterial gels and synthetic alginate were very similar. The survival of bacterial cultures in gel and their continuous release are significant findings in the development of novel bioinoculants based on this new concept.
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Self-encapsulation of Plant Growth Promoting Rhizobacteria as a way towards new generation of bioinoculants
Gašparová, Dominika ; Obruča, Stanislav (oponent) ; Sedláček, Petr (vedoucí práce)
This bachelor thesis focuses on Plant Growth-Promoting Rhizobacteria that can be used as a suitable ecological alternative to conventional fertilizers. However, most of today's approaches to incorporating PGPR into the process of soil fertilization are convoluted and costly. Crosslinking of alginate self-produced by PGPR offers a new possibility of plantgrowth- promoting bacteria encapsulation. The aim of this thesis consists of preparing gel matrices with incorporated bacteria, followed by testing the bacteria's viability and quantity. Firstly, experiments were carried out to determine various properties of gels produced by the chosen representative bacteria Azotobacter vinelandii. These properties include the molecular weight of alginate (with the highest molecular weight of strain CCM 289 (329,78± 6,8) kDa), the alginate's amount in the gel, the content of PHB (34%-44% CDW), and the gel's overall rheological properties. The complex modulus (as a representation of rheological properties) of the firmest gel reached the value of 13,34 kPa. The bacteria content was examined by flow cytometry, the CFU method, and spectrophotometry. The viability of bacteria was determined by analyzing the fluorescence intensity via fluorescent dyes (propidium iodide, fluorescein diacetate, rhodamine 123, calcein AM), then by using the CFU method, and also via the plate method. Furthermore, the effects of various factors such as different pH levels (pH 3, 7, and 10) or adding the specific alginatedegrading enzyme alginase were also examined. Releasing of the bacteria was observed over the course of seven days using flow cytometry and the CFU method. The plate method proved the bacteria's survival after gelation and without any source of carbon. The largest disintegration of gels occurred in acidic pH. Moreover, the effect of alginase on crosslinked bacterial gels and synthetic alginate were very similar. The survival of bacterial cultures in gel and their continuous release are significant findings in the development of novel bioinoculants based on this new concept.
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The portrayal of women in Slovak print media advertising 1992 - 2012.
Gašparová, Dominika ; Vinopal, Jiří (vedoucí práce) ; Hamplová, Dana (oponent)
Anotácia Diplomová práca Obraz ženy v tlačenej reklame slovenských médií v období 1992-2012 sa zaoberá spôsobom zobrazovania žien v reklame troch vybraných slovenských časopisov, a to v troch časových obdobiach: v roku 1992, 2002 a 2012. Týmto spôsobom chce práca odhaliť, akým smerom sa vyvíjalo zobrazovanie žien v reklame časopisov v čase, od kedy začína reklama v médiách zaberať stále viac priestoru. Práca sa zaoberá genderovou problematikou a zameriava sa hlavne na role, aké ženy v reklame zastávajú, ich pasivitu či aktivitu a sexuálnu objektivizáciu, ktoré skúma metódou obsahovej a semiotickej analýzy. Dvojaký spôsob analýzy nám umožní lepšie pochopiť mechanizmy zobrazovania žien v reklame ako aj vzájomné porovnanie spôsobu zobrazovania žien v médiách v závislosti na cieľovej skupine.
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