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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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Effects of light on the growth and miliacin content in common millet
RYBAROVÁ, Kateřina
This diploma thesis focuses on the effect of light on the growth and content of miliacin in millet panicum (Panicum milliaceum L.). A field trial on the ground of the Faculty of Agriculture and Technology at the University of South Bohemia in České Budějovice was set up with varieties Unikum, Kornberg and Hanácka Mana. Plant samples were taken at the time of clustering and maturity, and the height and weight of individual parts were determined together with the content of miliacin. Next, a lab trial with Unikum variety was set up, when the seeds were germinated for 11 days under the different wavelengths of colored spectrum of visible light and then the germination rate, the length and weight of the obtained sprouts were determined, and the analysis of the miliacin content was performed. The amount of miliacin in a dry matter was determined using gas chromatography coupled to mass spectrometry.
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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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Insect cold tolerance and seasonal changes in composition of sterols and tocopherols
URBAN, Tomáš
Presented work focused on researching cold resistance in insects (Pyrrhocoris apterus), especially in qualitative and quantitative composition and seasonal changes in the content of tocopherols and sterols in membranes. Collection of samples, tissue extraction, separation, sample preparation and the final analysis was included. There were detected three different sterols (animal cholesterol, plant sterols: campesterol and sitosterol). Also were detected ?-tocopherol and ?-tocopherol. Volume of cholesterol was in the range of 0.2 to 0.8 mol%, for phytosterols was the range from 1.2 to 15.2 mol%, and for tocopherols was the range from 0.1 to 31.3 mol%. Seasonal fluctuations of sterols and tocopherols were evaluated with a minimum in summer and maximum in winter.
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