National Repository of Grey Literature 2 records found  Search took 0.02 seconds. 
Role of the low-molecular metabolites in the development of yeast colonies
Bezdíčka, Martin ; Palková, Zdena (advisor) ; Dostál, Jiří (referee)
Previous research of colonies formed by yeast Saccharomyces cerevisiae growing on glycerol agar medium revealed two major cell types of U and L cells that are formed within these colonies. This colonial cell differentiation seem to be caused by communication among yeast cells as well as whole colonies and affected by changes in the environment (for example changes in nutrients). Studies of U and L cells showed that U cells are more resistant against biological, chemical and physical stresses than L cells. The aim of this thesis was to isolate U and L cell types and investigate their resistance against selected low molecular weight chemical substances produced in Ehrlich pathway. Ehrlich pathway was discovered in 1907 and was classified as amino acid catabolic pathway in yeast S. cerevisiae. The low molecular intermediates are formed in Ehrlich pathway which are called fusel (original name from German) alcohols and acids. These chemical substances are widely used in food industry and cosmetics especially because of their aroma. Several studies provided indications that these chemical substances may affect development of colonies and important yeast functions such as switching to the pseudohypfal growth of S. cerevisiae cells. Some chemical substances of the Ehrlich pathway were selected and their effects on...
Differentiation within yeast populations of Saccharomyces cerevisiae: influence of cultivation conditions
Šimek, Jan ; Palková, Zdena (advisor) ; Dostál, Jiří (referee)
Long-time research of chronologically aging yeast populations of Saccharomyces cerevisiae laboratory strains revealed that yeasts are able to differentiate into specialized cell types. Differentiation of liquid cultures growing in glucose rich medium and differentiation of colonies growing on solid glycerol medium has been previously studied. These populations create two fractions of cells with diverse morphology which adapt their metabolism and physiology to enable a long-term survival of the yeast population in environment with limited nutritional potential. In this study, yeast subpopulations isolated from colonies growing on solid glucose medium and liquid cultures cultivated in glycerol medium were characterized. Newly isolated cell types were compared with already known cell types isolated from colonies and liquid cultures. Selected metabolic processes and stress resistance were analysed in studied populations. Based on previous studies of yeast differentiation, a spectrum of GFP-labelled marker proteins was choosen and production and localization of these marker proteins was monitored within yeast populations. Results of the analyses showed that type of medium and cultivation influence development and metabolism of each yeast cell type. Key words: Saccharomyces cerevisiae, BY4742, cell...

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