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Characterization of biological effects of extracts obtained from yeasts and autotrophic microorganisms
Špačková, Dominika ; Bendová, Agáta (referee) ; Szotkowski, Martin (advisor)
Carotenogenic yeasts and microscopic autotrophic microorganisms are increasingly being studied in the biotechnology industry because of their ability to produce a variety of substances with a wide range of utilization. These substances mainly include lipids and carotenoids, which are used in the food and pharmaceutical industries. The aim of this bachelor thesis is to determine the way these microorganisms behave in the presence of stress factors, and which of them would have a positive effect on the production of metabolites that can be further used in various industries. The theoretical part is dedicated to a characterization of substances produced by carotenogenic yeasts, cyanobacteria and microalgae, which will be further analyzed in the experimental part. The metabolites mainly include carotenoids, which are a wide group of naturally occurring pigments that possess, among other things, antioxidant and provitamin activity. No less important substances produced by these organisms are lipids, which are part of cell membranes, they also serve as a reservoir of energy, and the substances contained in lipids are part of the precursors of many hormones. Yeast cell walls also contain -glucans, which have many beneficial effects on immunity and human health. Due to this fact, interest in their research have been rising recently. The analytical methods used to determine these substances are also mentioned, as well as stress factors and their effects on the cells of the mentioned organisms. The experimental part deals with the exposure of these microorganisms to oxidative stress and stress caused by heavy metals. The aim was to analyze which concentrations of these stress factors are lethal to microorganisms, and which of them are optimal for increase of the production of the above-mentioned substances. Of the yeast strains, the strains Sporidiobolus pararoseus and Rhodotorula mucilaginosa achieved increased production of metabolites due to selenate ions. In contrast, cobalt had a beneficial effect only on the accumulation of lipids and -glucans in cells. The positive effect of selenium was also observed in the strain Chlorella minutissima and Arthrospira maxima, however, the most remarkable changes in the production of metabolites were achieved by the addition of the optimal concentration of the solution inducing oxidative stress.
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Cultivation of carotenogenic yeasts in the presence of biological stress induced by selected strains of autotrophic microalgae
Sikorová, Pavlína ; Byrtusová, Dana (referee) ; Szotkowski, Martin (advisor)
Presented Master’s thesis was focused on biological and nutrient stress in cultivations of green microalgae and carotenogenic yeasts. The focus of interest was production of biomass in different types of cultivation media, production of metabolites (mainly carotenoids and chlorophylls) and also production of lipids and lipophilic substances. All types of aplied stress was used to lead to an increased production of biomass and metabolites. The theoretical part deals with introduction of individual genera of carotenogenic yeast and green microalgae. The types of cultivation stress were also described. In addition, the analytic methods for qualitative and quantitative analysis are also introduced. The experimental part was focused on the study of biomass, carotenoids, chlorophylls, coenzym Q, sterols and lipids production. Biological stress was induced by cocultivation of microalgae and yeasts together.Nutrient stress meant adding macroelements or waste oils to the medium. Yeasts of interest were Rhodosporidium toruloides, Rhodotorula kratochvilovae and Sporobolomyces pararoseus. Microalgae was represented by Desmodesmus acutus, Desmodesmus armatus, Scenedesmus obliquus, Desmodesmus velitaris, Desmodesmus communis, Coccomyxa sp. Chlamydomonas reinhardtii and Chlorella minutissima. Generally the most successful multicultivator experiment was cocultivation with yeast R. kratochvilovae. In the case of cultivation on waste oils, the best producers of biomass and metabolites were co-cultivation experiments with the yeast R. toruloides. In microalgal experiments, it was found that nutritional stress in the form of glycerol added to the medium had an inhibitory effect on the growth and metabolism of microalgae.
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Vliv stresu na pracovní výkon zaměstnanců
Pernicová, Natálie
Pernicová, N. The influence of stress on the work performance of employees: Men-del University in Brno, 2023. The bachelor thesis deals with the influence of stress on the work performan-ce of employees in two selected companies in different departments. The primary focus is on sales representatives (sales), followed by logistics and project ma-nagers. The results of the ji-ne departments and the logistics and project ma-nagement department are primarily used for comparison with the sales depart-ment to see the individual differences. Secondary data are presented to get a gene-ral idea of stress in the workplace. A questionnaire survey was used to investigate stress on the job performance of employees in the selected companies. In the practical part, the research in the form of questionnaire survey is applied in two companies namely GPD a.s. and Bosch Rexroth company s.r.o. The departments are investigated, which are divided into logistics, sales and other departments in GPD a.s. and other departments in Bosch Rexroth company s.r.o., which are divided into other departments, logistics, sales and project management departments. The questionnaire survey analyses the relationship between stress load and work per-formance in the individual companies in each department and then compares the companies with each other. According to the results of the questionnaire survey, recommendations are proposed for sales representatives and certain departments of the selected firms to minimize the stress factors in the selected firms. The re-commendations can subsequently lead to higher performance of the selected firms and higher sales. The recommendations are based on the results of the survey for example, introducing courses and training to help separate work life from co-private life can help to arrange "time management" so that employees can schedu-le their work duties well. Other recommendations are better communication between departments in the form of providing clearer and more precise informa-tion to each other, inter-departmental meetings where possible ambiguities can be clarified or merging events for better workplace relations between depart-ments, such as 'team building' and others.
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Study on metabolism of polyhydroxyalkanoates in bacterium Rhodospirillum rubrum
Pacasová, Viktorie-Alexandra ; Byrtusová, Dana (referee) ; Slaninová, Eva (advisor)
The present thesis focuses on polyhydroxyalkanoate (PHA) production in Rhodospirillum rubrum, comparing wild-type PHA-producing (R. rubrum) and mutant PHA-non-producing strains in terms of cell morphology. These bacterial strains were also subjected to selected stresses and the effect of PHA on the stress response was determined using advanced analytical techniques. The two strains used were first cultured under different conditions differing in light access, oxygen, culture time and substrate. The effect of culture conditions and PHA content on resistance to selected stressors - elevated temperature, osmotic stress and repeated freezing cycles - was then investigated. First, strains were cultured under aerobic conditions in the dark for 48 and 72 h. Viability of these samples was examined using a fluorescent probe (propidium iodide) by flow cytometry, while cell disruption was examined by electron microscopy. Furthermore, a similar experiment was performed in which the wild-type and mutant strains were cultured under microaerobic conditions in the light for 120 h to produce pigments (bacteriochlorophyll a and carotenoids). UV-VIS spectroscopy was used to determine the extracted pigments. The effect of culture time and conditions on the stress response was also determined for both bacterial strains by flow cytometry and electron microscopy. In the experimental part of the work, the ability to produce the copolymer P(3HB-co-3HV) was confirmed in a wild-type strain of R. rubrum. The hypothesis of the protective property of PHA granules when exposed to freezing cycles was also confirmed. In contrast, the protective function of PHA was not proven when exposed to osmotic stress.
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Optimization of cultivation conditions and production of metabolites by microalgae of the genus Desmodesmus and Scenedesmus in photobioreactors.
Kubalová, Michaela ; Mikulíková, Renata (referee) ; Szotkowski, Martin (advisor)
Nowadays, a lot of attention is being paid to the biotechnology industry. Within this industry, are with the help of microorganisms produced various useful substances, such as chlorophyll and carotenoids, which are important antioxidant substances, but also fatty acids, sterols and ubiquinone. This thesis is focused on the cultivation of selected strains of microalgae of the genus Scenedesmus and Desmodesmus. In the first part of the thesis, the algae strains and studied metabolites are described. In the second, experimental part, different types of alcohol were applied to the selected strains as stress conditions, with the aim of increasing the production of intracellular metabolites. Further, fermentor cultivation was carried out, in which a combination of two different alcohols was applied. Subsequently, cultivation using a flat-panel photobioreactor was also carried out, in which light with different wavelengths was used. Several chromatographic techniques were used for the analysis and the results of the analyzes are presented in the experimental part.
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Stress management in a selected company
VOKOUN, Jan
The thesis deals with the issue of stress and stress management in a selected organization. The aim of the thesis is to examine the stress factors and the impact of stress in the selected organization, including suggestions for changes in the current stress management in the organization. The sub-objectives of this thesis were to find out how the employees handle stress, how they approach stress management and also how they prevent stress and to recommend solutions if deficiencies are found. Based on this information, recommendations and suggestions were made to improve the current issues in the selected organization. For all the suggestions and recommendations, financial costing of the cases were graphically made. From the results, it is evident that the respondents are aware of the dangers of stress and burnout, irregular diet or lack of relaxation techniques, but do not practice any of these and do not actively address them. Therefore, I recommend assistance in implementing changes from the company and management, whether it be more emphasis on creating separate and enclosed spaces in the offices or other methods aimed at creating places of calm. The stated aim of the thesis has been fulfilled and its contribution to practice can be considered significant if the promising chance of using some of the proposals in the offices of OVB Allfinanz a. s. in České Budějovice turns into reality.
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Stress management and professional focus of workers
PECLINOVSKÝ, Ondřej
The thesis deals with stress management and the problem of stress in the workplace. The methodological approach is based on a questionnaire survey of three selected companies - Madeta a. s. (Madeta), ESW Bohemia k. s. (ESW) and the Central Institute for Inspection and Testing of Agriculture (ÚKZÚZ). The questionnaire was created on the office.com web-site and it contains 23 questions. The data are processed using appropriate graphs and tables through Microsoft office Word and Microsoft office Excel. The results show that in Madeta, most of the respondents are under stress (labourers) - they work in three shifts, in a fast pace most often individually and they are unable to resist the stress. In ÚKZÚZ (administrative workers and non-production type technicians), they work the morning shift in a calm pace and show little stress. Employees are aware of the consequences of long-term stress and therefore take care of themselves through appropriate activities. In ESW (administrative workers and production-type technicians), they work mainly in the morning shift and often in teams. Working in a team helps to reduce stress. Employees take care of themselves in appropriate ways to reduce stress.
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Stress management in a selected organization
SEKANINOVÁ, Denisa
The diploma thesis deals with the issue of stress and stress management in the workplace. The aim of the diploma thesis was to research the influence of stress, stress factors and their causes. Based on a questionnaire survey and an interview, changes are proposed in the current stress management of the company, including in financial terms.
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