Search results for "Saccharomyces"
showing 10 items of 861 documents
Proteomic Analysis of Saccharomyces cerevisiae Response to Oxidative Stress Mediated by Cocoa Polyphenols Extract
2020
The present study addressed the protective effects against oxidative stress (OS) of a cocoa powder extract (CPEX) on the protein expression profile of S. cerevisiae. A proteomic analysis was performed after culture preincubation with CPEX either without stress (&minus
The role of post-transcriptional modulators of metalloproteins in response to metal deficiencies
2021
Copper and iron proteins play a wide range of functions in living organisms. Metal assembly into metalloproteins is a complex process, where mismetalation is detrimental and energy-consuming to cells. Under metal deficiency, metal distribution is expected to reach a metalation ranking, prioritizing essential versus dispensable metalloproteins, while avoiding interferences with other metals and protecting metal-sensitive processes. In this review, we propose that posttranscriptional Modulators of Metalloprotein messenger RNA (ModMeR) are good candidates in metal prioritization under metal-limited conditions. ModMeR target high quota or redundant metalloproteins and, by adjusting their synthe…
Effect of nitrogen limitation and nature of the feed upon Oenococcus oeni metabolism and extracellular protein production
2005
Aims: The aim of the study was to characterize the effect of various nitrogen sources on Oenococcus oeni growth, carbon source utilization, extracellular protease activity and extracellular proteins. More generally, the goal is to understand how nitrogen-based additives might act to enhance malolactic fermentation in wine. Methods and Results: Five yeast extracts were used. As the amino acid and nitrogen analyses revealed, they were similar in global amino acid composition, except for arginine level. Nevertheless the ratio of amino acids between free/bound, and low/high molecular weight fractions were highly different. One of the yeast extracts led to a significant protease activity in th…
Comparison of Components Released by Fermented or Active Dried Yeasts after Aging on Lees in a Model Wine
2003
Comparison of different components released during autolysis with fermented or active dried yeast, which has never been reported previously, is related in this paper. Three autolysates were elaborated with Saccharomyces cerevisiae in a model wine (pH 3.5) at 30 or 18 degrees C. Composition of the autolysate appears to depend on both the growth medium and the physiological state of the yeast. The autolysate obtained from active dried yeast presents a higher total nitrogen concentration (a factor of 1.5-1.9 for the fermented yeast autolysate), a greater proportion of free amino acids (42 vs 16-25%), the lowest proportion of oligopeptides (25 vs 31-37%) and polypeptides (27 vs 45-34%), and an …
Protease A activity and nitrogen fractions released during alcoholic fermentation and autolysis in enological conditions
2000
Determination of protease A activity during alcoholic fermentation of a synthetic must (pH 3.5 at 25 degrees C) and during autolysis showed that a sixfold induction of protease A activity occurred after sugar exhaustion, well before 100% cell death occurred. A decrease in protease A activity was observed when yeast cell autolysis started. Extracellular protease A activity was detected late in the autolysis process, which suggests that protease A is not easily released. Evolution of amino acids and peptides was determined during alcoholic fermentation and during autolysis. Amino acids were released in early stationary phase. These amino acids were subsequently assimilated during the fermenta…
Evaluation of yeasts from Ecuadorian chicha by their performance as starters for alcoholic fermentations in the food industry
2020
Yeasts involved in the spontaneous fermentation of traditional beverages like chicha (indigenous Andean beer) may have the potential to be used as starter cultures to improve the quality and microbiological safety of these products, but also as non-conventional alternatives to other food alcoholic fermentations. In this research, we isolated, identified and characterised yeast strains from four Ecuadorian chichas made by using four different raw materials: rice (RC), oat (OC), grape (GC) and a mixture of seven corn varieties (yamor, YC). Finally, 254 yeast isolates were obtained and identified by molecular methods. Eleven yeast genera and 16 yeast species were identified with relatively few…
Cloning and characterization of the phenylalanyl-tRNA synthetase β subunit gene fromCandida albicans
1998
A Candida albicans expression library was constructed from RNA isolated from regenerating protoplasts. A 1.4-kb cDNA clone was used to isolate a genomic fragment. Sequence analysis revealed an open reading frame of 593 amino acids with an overall identity of 63.6% with the phenylalanyl-tRNA synthetase beta subunit (FRS1) of Saccharomyces cerevisiae. We named it CaFRS1. It is located in a single copy in chromosome R, SfiI fragment M. Its expression showed a decrease during the cell wall regeneration process in protoplasts of both yeast and mycelial cells of C. albicans, suggesting its requirement thereof in initial steps of the cell wall synthesis.
Technological screening and application of Saccharomyces cerevisiae strains isolated from fermented honey by-products for the sensory improvement of …
2021
“Spiritu re fascitrari” is a Sicilian alcoholic beverage obtained through distillation of a decoction of spontaneously fermented honey by-products (FHP). The production process often leads to sensorial defects due to the unstable alcoholic fermentation. The objective of this work was to select Saccharomyces cerevisiae strains from FHP to be used as starter in decoction fermentation. Based on chemical, microbiological and technological data, from a total of 91 strains three S. cerevisae were selected for further testing to produce FHP at laboratory scale level. After FHP distillation, the analysis of volatile organic compounds showed a complex mixture of sensory active molecules, mainly alco…
Protection of Saccharomyces cerevisiae by a layer-by-layer system : effect on yeast metabolic activity in response to environmental conditions
2016
In order to protect the Saccharomyces cerevisiae yeast during dehydration, two strategies were used to improve cell survival. Strengthening cell resistance (internal protection) was performed by improving the concentration of intracellular glutathione in yeast. Encapsulation was performed by layer-by-layer method using two biopolymers β-lactoglobulin and alginate for the external protection of the yeast. The adequate medium culture and favorable growing conditions for glutathione enhancement were determined. The composition of the culture medium is rich in nutrients and glutathione precursors consisting in 30 g/L glucose, 30 g/L yeast extract, 0.6 g/L KH2PO4 and 0.6 g/L cysteine. The succes…
TORC1 controls G1–S cell cycle transition in yeast via Mpk1 and the greatwall kinase pathway
2015
The target of rapamycin complex 1 (TORC1) pathway couples nutrient, energy and hormonal signals with eukaryotic cell growth and division. In yeast, TORC1 coordinates growth with G1–S cell cycle progression, also coined as START, by favouring the expression of G1 cyclins that activate cyclin-dependent protein kinases (CDKs) and by destabilizing the CDK inhibitor Sic1. Following TORC1 downregulation by rapamycin treatment or nutrient limitation, clearance of G1 cyclins and C-terminal phosphorylation of Sic1 by unknown protein kinases are both required for Sic1 to escape ubiquitin-dependent proteolysis prompted by its flagging via the SCFCdc4 (Skp1/Cul1/F-box protein) ubiquitin ligase complex.…