Search results for "Saccharomyce"
showing 10 items of 875 documents
Biodiversité fongique du raisin au vin : impact de l'activité anthropique
2016
The effects of different anthropogenic activities (vineyard, winery) on fungal populations from grape to wine were studied. To characterize these effects, it was necessary to access to the overall diversity of populations (pyrosequencing and spectroscopy FT-IR) but also to intra-specific diversity (FT-IR). Spectroscopy FT-IR has been validated for their ability to characterize the global population and to discriminate the strains for three species of non-Saccharomyces yeasts (NS). For the first time, it is shown that the grape berry is a limited source for NS yeasts while the winery seems to be a significant source; the air is an important vector for dissemination of these yeasts. In additi…
Involvement of the plasma membrane in saccharomyces cerevisiae resistance to hydric perturbations : key role of ergosterol
2011
Preservation of microorganisms of interest (ferments, probiotics) in dry form is widespread in the industry. However, the dehydration processes lead to variable survival rates according to the group, species and strain of microorganism considered, but also according to the type of process used (drying, freeze drying, freezing). The plasma membrane (PM), by its position between the intra-and extracellular environment, is a target of hydric perturbations. Changes in this structure during hydric stresses are described to be directly involved in microorganism death. Understanding of membrane responses occurring during a dehydration/rehydration cycle is essential to maximize the survival of micr…
Population Structure and Comparative Genome Hybridization of European Flor Yeast Reveal a Unique Group of Saccharomyces cerevisiae Strains with Few G…
2014
Wine biological aging is a wine making process used to produce specific beverages in several countries in Europe, including Spain, Italy, France, and Hungary. This process involves the formation of a velum at the surface of the wine. Here, we present the first large scale comparison of all European flor strains involved in this process. We inferred the population structure of these European flor strains from their microsatellite genotype diversity and analyzed their ploidy. We show that almost all of these flor strains belong to the same cluster and are diploid, except for a few Spanish strains. Comparison of the array hybridization profile of six flor strains originating from these four co…
Rôle de la membrane plasmique dans la survie des microorganismes à la déshydratation : Contribution à l’optimisation de procédés de conservation des …
2010
Cette synthèse est consacrée au rôle de la membrane plasmique des microorganismes, à travers ses évolutions structurales et fonctionnelles, dans la survie à la déshydratation. Elle comprend une première partie dans laquelle sont regroupés les principaux résultats portant sur l’influence de la déshydratation sur la survie microbienne, sur le comportement membranaire in situ et sur les mécanismes physiques de la déstabilisation membranaire. La deuxième partie est consacrée à la transposition de cette compréhension aux applications de déshydratation industrielle des microorganismes. Elle porte sur le développement d’un procédé de déshydratation des microorganismes et sur la mise au point d’out…
Engineering a Saccharomyces cerevisiae Wine Yeast That Exhibits Reduced Ethanol Production during Fermentation under Controlled Microoxygenation Cond…
2006
ABSTRACTWe recently showed that expressing an H2O-NADH oxidase inSaccharomyces cerevisiaedrastically reduces the intracellular NADH concentration and substantially alters the distribution of metabolic fluxes in the cell. Although the engineered strain produces a reduced amount of ethanol, a high level of acetaldehyde accumulates early in the process (1 g/liter), impairing growth and fermentation performance. To overcome these undesirable effects, we carried out a comprehensive analysis of the impact of oxygen on the metabolic network of the same NADH oxidase-expressing strain. While reducing the oxygen transfer rate led to a gradual recovery of the growth and fermentation performance, its i…
Rbt1 Protein Domains Analysis in Candida albicans Brings Insights into Hyphal Surface Modifications and Rbt1 Potential Role during Adhesion and Biofi…
2013
Cell wall proteins are central to the virulence of Candida albicans. Hwp1, Hwp2 and Rbt1 form a family of hypha-associated cell surface proteins. Hwp1 and Hwp2 have been involved in adhesion and other virulence traits but Rbt1 is still poorly characterized. To assess the role of Rbt1 in the interaction of C. albicans with biotic and abiotic surfaces independently of its morphological state, heterologous expression and promoter swap strategies were applied. The N-terminal domain with features typical of the Flo11 superfamily was found to be essential for adhesiveness to polystyrene through an increase in cell surface hydrophobicity. A 42 amino acid-long domain localized in the central part o…
Akvaporīnu loma raugu šūnu dehidratācijas procesā
2018
Bakalaura darba mērķis bija izpētīt akvaporīnu lomu raugu šūnās dehidratācijas un sekojošas rehidratācijas laikā. Lai sasniegtu šo mērķi izmantoja sekojošos rauga Saccharomyces cerevisiae celmus: ANT29 - izejas celmu ar AQY1 un AQY2 akvaporīnu gēniem, ANT27 - celms ar AQY1 gēna pārekspresiju, un YSH1172 - celms ar abu akvaporīnu gēnu delēciju, kurus sadarbības ietvaros piegādāja Lisabonas Universitāte. Dehidratācijas eksperimentiem izmantoja šūnas no stacionārās augšanas fāzes, kura iestājās 30. augšanas stundā visiem celmiem līdzīgi. Pētīja raugu rezistenci dehidratācijai atkarīgi no pavadīta laika stacionārajā augšanas fāzē. Iegūtie dati parādīja, ka AQY1 pārekspresija raugu šūnās neietek…
Non-
2017
Nitrogen sources in the must are important for yeast metabolism, growth, and performance, and wine volatile compounds profile. Yeast assimilable nitrogen (YAN) deficiencies in grape must are one of the main causes of stuck and sluggish fermentation. The nitrogen requirement of Saccharomyces cerevisiae metabolism has been described in detail. However, the YAN preferences of non-Saccharomyces yeasts remain unknown despite their increasingly widespread use in winemaking. Furthermore, the impact of nitrogen consumption by non-Saccharomyces yeasts on YAN availability, alcoholic performance and volatile compounds production by S. cerevisiae in sequential fermentation has been little studied. With…
Raugu Saccharomyces cerevisiae žāvēšanas rezistences mehanismu pētījumi
2017
. Tika veikta divu rauga Saccharomyces cerevisiae celmu salīdzināšana - mēreni rezistenta S. cerevisiae 14 un izturīga pret žāvēšanu S. cerevisiae 77 celma, audzēšanai izmantojot dažādus barotņu sastāvus. Ir pētītas rauga šūnu to citoplazmatiskās membrānas funkcionālā stāvokļa izmaiņas pārejot anabiozes stāvoklī. Vēlāk par vispiemērotāko tika izvēlēta YPG barotne. Turpinot eksperimentus rauga biomasa pirms dehidratācijas tika 3 stundas inkubēta dažādos sķīdumos ar augstu osmotisko spiedienu, t.i. laktozes un ksilīta šķīdumi. Tas deva iespēju apskatīt šūnu izdzīvotības palielināšanas spējas un novērtēt izmaiņas šūnu lipīdu uzkrāšanās pēc dehidratācijas. Darbā tika izmantotas vairākas …
The influence of yeast glycosylated proteins on tannins aggregation in model solution
2004
<p style="text-align: justify;">The incidence of glycosylated yeast proteins on tannins aggregation in model solution was investigated using the spectrophotometric method (absorbance 700 nm). Glycosylated proteins released by two commercial <em>Saccharomyces cerevisiae</em> strains (RC212 and BM 45) during alcoholic fermentation in synthetic media, glycosylated proteins extracted by Peat’s method and industrial glycosylated proteins purified and separated by chromatography on Sepharose Concanavalin A were used to visualize effects on tannins aggregation. Results showed that tannins aggregation was limited by the glycosylated proteins according to their origin and their mod…