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S. Cerevisiae Cells (s + cerevisiae_cell)
Selected AbstractsSaccharomyces cerevisiae Ybr004c and its human homologue are required for addition of the second mannose during glycosylphosphatidylinositol precursor assemblyFEBS JOURNAL, Issue 5 2005Anne-Lise Fabre Addition of the second mannose is the only obvious step in glycosylphosphatidylinositol (GPI) precursor assembly for which a responsible gene has not been discovered. A bioinformatics-based strategy identified the essential Saccharomyces cerevisiae Ybr004c protein as a candidate for the second GPI ,-mannosyltransferase (GPI-MT-II). S. cerevisiae cells depleted of Ybr004cp have weakened cell walls and abnormal morphology, are unable to incorporate [3H]inositol into proteins, and accumulate a GPI intermediate having a single mannose that is likely modified with ethanolamine phosphate. These data indicate that Ybr004cp-depleted yeast cells are defective in second mannose addition to GPIs, and suggest that Ybr004cp is GPI-MT-II or an essential subunit of that enzyme. Ybr004cp homologues are encoded in all sequenced eukaryotic genomes, and are predicted to have 8 transmembrane domains, but show no obvious resemblance to members of established glycosyltransferase families. The human Ybr004cp homologue can substitute for its S. cerevisiae counterpart in vivo. [source] Organelle-specific expression of subunit ND5 of human complex I (NADH dehydrogenase) alters cation homeostasis in Saccharomyces cerevisiaeFEMS YEAST RESEARCH, Issue 6 2010Wojtek Steffen Abstract The ND5 component of the respiratory complex I is a large, hydrophobic subunit encoded by the mitochondrial genome. Its bacterial homologue, the NDH-1 subunit NuoL, acts as a cation transporter in the absence of other NDH-1 subunits. Mutations in human ND5 are frequently observed in neurodegenerative diseases. Wild type and mutant variants of ND5 fused to GFP or a FLAG peptide were targeted to the endoplasmatic reticulum (ER) or the inner mitochondrial membrane of Saccharomyces cerevisiae, which lacks an endogenous complex I. The localization of ND5 fusion proteins was confirmed by microscopic analyses of S. cerevisiae cells, followed by cellular fractionation and immunostaining. The impact of the expression of ND5 fusion proteins on the growth of S. cerevisiae in the presence and absence of added salts was studied. ER-resident ND5 conferred Li+ sensitivity to S. cerevisiae, which was lost when the E145V variant of ND5 was expressed. All variants of ND5 tested led to increased resistance of S. cerevisiae at high external concentrations of Na+ or K+. The data seem to indicate that ND5 influences the salt homeostasis of S. cerevisiae independent of other complex I subunits, and paves the way for functional studies of mutations found in mitochondrially encoded complex I genes. [source] Heterologous expression of a Clostridium minicellulosome in Saccharomyces cerevisiaeFEMS YEAST RESEARCH, Issue 8 2009Mariska Lilly Abstract The yeast Saccharomyces cerevisiae was genetically modified to assemble a minicellulosome on its cell surface by heterologous expression of a chimeric scaffoldin protein from Clostridium cellulolyticum under the regulation of the phosphoglycerate kinase 1 (PGK1) promoter and terminator regulatory elements, together with the ,-xylanase 2 secretion signal of Trichoderma reesei and cell wall protein 2 (Cwp2) of S. cerevisiae. Fluorescent microscopy and Far Western blot analysis confirmed that the Scaf3p is targeted to the yeast cell surface and that the Clostridium thermocellum cohesin domain is functional in yeast. Similarly, functionality of the C. thermocellum dockerin domain in yeast is shown by binding to the Scaf3 protein in Far Western blot analysis. Phenotypic evidence for cohesin,dockerin interaction was also established with the detection of a twofold increase in tethered endoglucanase enzyme activity in S. cerevisiae cells expressing the Scaf3 protein compared with the parent strain. This study highlights the feasibility to future design of enhanced cellulolytic strains of S. cerevisiae through emulation of the cellulosome concept. Potentially, Scaf3p-armed yeast could also be developed into an alternative cell surface display strategy with various tailor-made applications. [source] Gene expression study of Saccharomyces cerevisiae under changing growth conditionsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2009Pengcheng Fu Abstract BACKGROUND: DNA microarrays technology has been used to obtain expression profiles of thousands of genes at the same time for a given organism at relatively low costs. While gene expression approaches are being developed which allow holistic analysis of complex biological processes, there exist very few illustrative examples on the integration of large scale modeling and high throughput time course experiments to upgrade the information contents on yeast biology. RESULTS:Saccharomyces cerevisiae cell culture experiments with perturbed growth conditions were designed so that the metabolic states would be shifted from one to another. Microarrays were used to explore changes in gene expression across the entire yeast genome during the perturbation experiments. Changes in transcript abundance in these growth periods were investigated to study the cellular response to different glucose and oxygen supply. Computational results and experimental observations representing the three characteristic metabolic states were compared on the S. cerevisiae metabolic pathways, as well as the visualization platform provided by the metabolic phenotypic phase plane (PhPP) for the gene regulation on cell metabolism and adaptation of cells to environmental changes. CONCLUSIONS: The integrated expression study described reveals that S. cerevisiae cells respond to environmental changes mainly by down-regulating a number of genes to alter the cell metabolism so that the cells adapt to the variations in their growth conditions. Copyright © 2009 Society of Chemical Industry [source] INFLUENCE OF PULSED ELECTRIC FIELD ON SELENOCYSTEINE CONTENT IN SACCHAROMYCES CEREVISIAEJOURNAL OF FOOD BIOCHEMISTRY, Issue 6 2008URSZULA PANKIEWICZ ABSTRACT Culture of Saccharomyces cerevisiae with sodium selenite addition in medium was treated by pulsed electric fields (PEFs). Amino acids from yeast hydrolysates were separated by means of ion-exchange chromatography on amino acid analyzer according to previously established procedure. Selenocysteine was determined in a form of complex with ninhydrin, applying photometric technique. PEF treatment of S. cerevisiae cells resulted in about threefold content increase of selenium bonded within selenocysteine. PRACTICAL APPLICATIONS Se yeast is an attractive source of Se because of its low cost and its ability to act as a precursor for selenoprotein synthesis. Se yeast can be consumed as such and as a nutritional supplement. Another possibility is to use selenized yeast instead of conventional yeast for baking bread. Bread is generally low in Se, and hence the use of selenized yeast for this purpose could result in higher Se intakes because bread is a common product consumed by many individuals (Dumont et al. 2006). The presented way to enrich the baking yeast in selenium, namely selenomethionine, may be successfully applied in yeast production, because the studied method is a relatively simple, nontoxic and cheap technique for introducing macrocompounds into the yeast cells. Such enriched selenium yeast may be a valuable and safe source of selenium at diet supplementation. [source] | ||||||||||