Search results for "S.cerevisiae"
showing 10 items of 747 documents
Enhanced fermentative capacity of yeasts engineered in storage carbohydrate metabolism.
2014
During yeast biomass production, cells are grown through several batch and fed-batch cultures on molasses. This industrial process produces several types of stresses along the process, including thermic, osmotic, starvation, and oxidative stress. It has been shown that Saccharomyces cerevisiae strains with enhanced stress resistance present enhanced fermentative capacity of yeast biomass produced. On the other hand, storage carbohydrates have been related to several types of stress resistance in S. cerevisiae. Here we have engineered industrial strains in storage carbohydrate metabolism by overexpressing the GSY2 gene, that encodes the glycogen synthase enzyme, and deleting NTH1 gene, that …
Protection of living yeast cells by micro-organized shells of natural polyelectrolytes
2015
International audience; Saccharomyces cerevisiae, a eukaryotic model organism, plays a key role in the oxidative stability of fermented products. In order to protect cells against environmental stresses, we report a method of modifying the cell surface architecture while maintaining the internal working properties of the system. The objective was to encapsulate living yeast cells in micro-organized polyelectrolyte shells using layer-by-layer (LbL) assembly. For the first time, the natural polyelectrolytes, β-lactoglobulin and sodium alginate, were alternately deposited on the surface of S. cerevisiae. Transmission electron microscopy coupled with immune-cytochemistry and scanning electron m…
On the fermentative behavior of auxotrophic strains of Saccharomyces cerevisiae
2014
Background: The selection of new yeast strains could lead to improvements in bioethanol production. Here, we have studied the fermentative capacity of different auxotrophic mutants of Saccharomyces cerevisiae, which are routinely used as hosts for the production of heterologous proteins. It has recently been found that these strains exhibit physiological alterations and peculiar sensitivities with respect to the parental prototrophic strains from which they derive. In this work the performance of auxotrophic S. cerevisiae CEN.PK strains was compared to the corresponding prototrophic strain, to S. cerevisiae T5bV, a strain isolated from grape must and to another auxotrophic strain, S. cerevi…
Thermotolerance in Saccharomyces cerevisiae is linked to resistance to anhydrobiosis
2014
Abstract We have demonstrated that a thermotolerant yeast strain ( Saccharomyces cerevisiae TS1) is much more resistant to dehydration–rehydration treatments than a mesophilic strain of S. cerevisiae . Yeast resistance to dehydration–rehydration was found to be similar in cells from exponential and stationary growth phases. Under controlled rehydration conditions involving gradual rehydration in water vapour, yeast cell viability was maintained at 90–95%. When S. cerevisiae TS1 cells were pre-grown at 37 °C and then dried, controlled rehydration lead to restoration of plasma membrane integrity, indicating important differences in cell envelope architechture of mesophilic and thermotolerant …
Influence of nitrogen status in wine alcoholic fermentation
2019
Nitrogen is an essential nutrient for yeast during alcoholic fermentation. Nitrogen is involved in the biosynthesis of protein, amino acids, nucleotides, and other metabolites, including volatile compounds. However, recent studies have called several mechanisms that regulate its role in biosynthesis into question. An initial focus on S. cerevisiae has highlighted that the concept of "preferred" versus "non-preferred" nitrogen sources is extremely variable and strain-dependent. Then, the direct involvement of amino acids consumed in the formation of proteins and volatile compounds has recently been reevaluated. Indeed, studies have highlighted the key role of lipids in nitrogen regulation in…
Identification and structural characterization of O-beta-ribosyl-(1"----2')-adenosine-5"-phosphate in yeast methionine initiator tRNA.
1990
We report in this paper on the complete structure determination of the modified nucleotide A*, now called Ar(p), that was previously identified in yeast methionine initiator tRNA as an isomeric form of O-ribosyl-adenosine bearing an additional phosphoryl-monoester group on its ribose2 moiety. By using the chemical procedure of periodate oxidation and subsequent beta-elimination with cyclohexylamine on mono- and dinucleotides containing Ar(p), we characterized the location of the phosphate group on the C-5" of the ribose2 moiety, and the linkage between the two riboses as a (1"----2')-glycosidic bond. Since the structural difference between phosphatase treated Ar(p) and authentic O-alpha-rib…
Fractionated precipitation of acid macropolyanions by dialysis, a simple method for the estimation of DNA in complex biological samples.
1976
Abstract After efficient extraction by para-aminosalicylate, (hopping, grinding and eventual sonication, the macropolyanions are transformed into their cetyltrimethylammonium salts. These have differing solubilities, strongly depending on ionic strength. The cationic detergent-macropolyanionic salts are solubilized by high salt concentration. Salt is then dialysed out, rendering the polyanions highly insoluble in a sequential fashion. The insolubilized components are determined quantitatively by monitoring turbidity, which in case of DNA is strictly proportionate to its concentration. This relation is not affected by other components. This makes DNA determination possible even in crude aque…
Hypusinated eIF5A is required for the translation of collagen.
2021
ABSTRACT Translation of mRNAs that encode peptide sequences with consecutive prolines (polyproline) requires the conserved and essential elongation factor eIF5A to facilitate the formation of peptide bonds. It has been shown that, upon eIF5A depletion, yeast ribosomes stall in polyproline motifs, but also in tripeptide sequences that combine proline with glycine and charged amino acids. Mammalian collagens are enriched in putative eIF5A-dependent Pro-Gly-containing tripeptides. Here, we show that depletion of active eIF5A in mouse fibroblasts reduced collagen type I α1 chain (Col1a1) content, which concentrated around the nuclei. Moreover, it provoked the upregulation of endoplasmic reticul…
Relationships between metabolic fluxes and enzyme amino acid composition
2013
AbstractMetabolic fluxes are a key parameter of metabolic pathways being closely related to the kinetic properties of enzymes and could be conditional on their sequence characteristics. This study examines possible relationships between the metabolic fluxes and the amino acid (AA) composition (AAC) for enzymes from the yeast Saccharomyces cerevisiae glycolysis pathway. Metabolic fluxes were quantified by the COPASI tool using the kinetic models of Hynne and Teusink at 25 mM, 50 mM, and 100 mM of external glucose or employing literature data for cognate kinetic or stoichiometric models. The enzyme sequences were taken from the UniProtKB, and the AAC computed by the ExPASy/ProtParam tool. Mul…
Sequence of a new tRNALeu(U∗AA) from brewer's yeast
1991
The nucleotide sequence of a new tRNA(Leu)(anticodon U*AA) from Saccharomyces cerevisiae which could recognize exclusively the UUA codon has been determined. Its primary structure is: pGGAGGGUUGm2GCac4CGAGDGmGDCDAAGGCm2(2)GGCAGACmUU*AAm1GA++ + psi CUGUUGGACGGUUGUCCGm5CGCGAGT psi CGm1A(orA)ACCUCGCAUCCUUCACCA. This tRNA has a large extraloop and contains 15 modified nucleotides. So far it is the third isoacceptor tRNA for leucine in yeast. It has 61% homology with tRNA(Leu)(anticodon m5CAA) and 63% homology with tRNA(Leu)(anticodon UAG), the two other known yeast tRNAs(Leu).