Project description:Our study involves a transcriptomic approach to the analysis of industrial yeast metabolism. Historically, among the hundreds of yeast species, Saccharomyces cerevisiae has played an important role in scientific investigations and industrial applications, and it is universally acknowledged as one of the model systems for eukaryotic organisms. Yeast is also an important component of the wine fermentation process and determines various attributes of the final product. Our research takes a holistic approach to the improvement of industrial yeast strains by integrating large data sets from various yeast strains during fermentation. This means that analysis can be done in such a way as to co-evaluate several parameters simultaneously to identify points of interest and target genes for metabolic engineering. Eventually we hope to construct an accurate information matrix and a more complete cellular map for the fermenting yeast. This will enable accurate model-building for industrial yeast and facilitated the design of intelligent yeast improvement strategies which can be applied via traditional avenues of molecular biology. Experiment Overall Design: Five different Saccharomyces cerevisiae strains used in industrial winemaking processes were used in synthetic must (MS300) fermentations. All fermentations were carried out in triplicate, so each sample is represented by three completely independent biological repeats. Samples for microarray analysis were taken at three different time points during fermentation, representative of the exponential (day2), early stationary (day5) and late stationary (day14) growth stages.
Project description:Comparative gene expression analysis of two wine yeast strains at three time points (days 2, 5 and 14) during fermentation of colombar must. In our study we conducted parallel fermentations with the VIN13 and BM45 wine yeast strains in two different media, namely MS300 (syntheticmust) and Colombar must. The intersection of transcriptome datasets from both MS300 (simulated wine must;GSE11651) and Colombar fermentations should help to delineate relevant and ânoisyâ changes in gene expression in response to experimental factors such as fermentation stage and strain identity. Experiment Overall Design: Two industrial wine yeast strains (BM45 and VIN13) grown micro-aerobically in Colombar must. Microarray analysis was performed at three time points during fermentation (days 2, 5 and 14), representing the exponential, early and late stationary growth phases respectively.
Project description:Comparative gene expression analysis of two wine yeast strains at three time points (days 2, 5 and 14) during fermentation of colombar must. In our study we conducted parallel fermentations with the VIN13 and BM45 wine yeast strains in two different media, namely MS300 (syntheticmust) and Colombar must. The intersection of transcriptome datasets from both MS300 (simulated wine must;GSE11651) and Colombar fermentations should help to delineate relevant and ‘noisy’ changes in gene expression in response to experimental factors such as fermentation stage and strain identity.
Project description:Transcriptomic analyses of fermenting yeast are increasingly being carried out under small scale simulated winemaking conditions. It is not known to what degree data generated from such experiments are a reflection of transcriptional processes in large-scale commercial fermentation tanks. In this experiment we set out to determine the effect of scale, or fermentation volume, on the transcriptional respone of wine yeast strains. Parallel fermentations were carried out in laboratory fermentation vials and commercial fermentation tanks using the same wine media and inoculated yeast strain. Comparative transcriptomic analyses were carried out at three time points during alcoholic fermentation.
Project description:Our study involves a transcriptomic approach to the analysis of industrial yeast metabolism. Historically, among the hundreds of yeast species, Saccharomyces cerevisiae has played an important role in scientific investigations and industrial applications, and it is universally acknowledged as one of the model systems for eukaryotic organisms. Yeast is also an important component of the wine fermentation process and determines various attributes of the final product. Our research takes a holistic approach to the improvement of industrial yeast strains by integrating large data sets from various yeast strains during fermentation. This means that analysis can be done in such a way as to co-evaluate several parameters simultaneously to identify points of interest and target genes for metabolic engineering. Eventually we hope to construct an accurate information matrix and a more complete cellular map for the fermenting yeast. This will enable accurate model-building for industrial yeast and facilitated the design of intelligent yeast improvement strategies which can be applied via traditional avenues of molecular biology.
Project description:Gene expression analysis of a time course experiment of a synthetic must (nitrogen-poor) fermentation by a natural wine yeast. Three replicates of five time points taken at 24, 48, 80, 96 and 144 hours after yeast inoculation
Project description:Gene expression analysis of a time course experiment of a synthetic must (nitrogen-poor) fermentation by a natural wine yeast, supplemented at 72 hours with 200 mg/l of nitrogen Three replicates of five time points taken at 24, 48, 80, 96 and 144 hours after yeast inoculation. Time points 24 and 48 hours are common to Sluggish fermentation. Time points at 80, 96 and 144 hours are exclusive of this experiment.
Project description:Industrial wine yeast strains possess specific abilities to ferment under stressing conditions and give a suitable aromatic outcome. Although the fermentations properties of Saccharomyces cervisiae wine yeasts are well documented little is known on the genetic basis underlying the fermentation traits. Besides, although strain differences in gene expression has been reported, their relationships with gene expression variations and fermentation phenotypic variations is unknown. To both identify the genetic basis of fermentation traits and get insight on their relationships with gene expression variations, we combined fermentation traits QTL mapping and expression profiling in a segregating population from a cross between a wine yeast derivative and a laboratory strain.
Project description:The main objectives of this study were to expand our understanding of NSF1 gene function in industrial S. cerevisiae M2 strain during fermentation by finding the largest maximal clique of co-expressed genes (i.e. Interdependent Correlation Cluster), and to establish the impact of Nsf1p on genome-wide gene expression during the fermentation process with possible implications related to wine quality and S. cerevisiae adapation to stressful fermentation conditions The Affymetrix Yeast 2.0 microarrays were used to capture the global gene expression profile of M2 and M2 nsf1∆ grown under fermentation conditions in Riesling grape must at 18°C with no shaking at various time points. The analysis of this microarray dataset expanded our understanding of the mechanism of action and the roles of NSF1 under fermentation stress conditions.
Project description:Laboratory strains of Saccharmoyces cerevisiae have been widely used as a model for studying eukaryotic cells and mapping the molecular mechanisms of many different human diseases. Industrial wine yeasts, on the other hand, have been selected over hundreds of years on the basis of their adaptation to stringent environmental conditions and the organoleptic properties they confer to wine. Here, we applied a two-factor design to study the response of a standard laboratory strain, CEN.PK.113-7D, and an industrial wine yeast-strain, EC1118, to growth temperature at 15°C and 30°C under 12 nitrogen-limited, anaerobic steady-state chemostat cultures. Physiological characterization revealed that growth temperature strongly impacted biomass yields in both strains. Moreover, we observed that the wine yeast is better adapted to mobilizing resources for biomass and that the laboratory yeast exhibited higher fermentation rates. To elucidate mechanistic differences controlling the growth temperature response and underlying adaptive mechanisms between strains, DNA microarrays and targeted metabolome analysis were used. We identified 1007 temperature dependent genes and 473 strain dependent genes. The transcriptional response was used to identify highly correlated subnetworks of significantly changing genes in metabolism. We show that temperature differences most strongly affect nitrogen metabolism and the heat shock response. Lack of STRE mediated gene induction, coupled with reduced trehalose levels, indicates a decreased general stress response at 15°C relative to 30°C. Between strains, differential responses are centred around sugar uptake, nitrogen metabolism and expression of genes related to organoleptic properties. Our study provides global insight into how growth temperature exerts a differential physiological and transcriptional response in laboratory and wine strains of S. cerevisiae.