Project description:Functional genomic analysis using different types of baker's yeast. Experiment Overall Design: Fermentation at different concentrations of sucrose. Experiment Overall Design: PerChip normalization using only positive (exclude pombe) genes and PerGene normalization were applied using GeneSpring (v7.0).
Project description:Gene expression profiles of baker’s yeast during initial dough-fermentation were investigated using liquid fermentation media to obtain insights at the molecular level into rapid adaptation mechanisms of baker’s yeast. Results showed that onset of fermentation caused drastic changes in gene expression profiles within 15 min. Genes involved in the tricarboxylic acid (TCA) cycle were down-regulated and genes involved in glycolysis were up-regulated, indicating a metabolic shift from respiration to fermentation. Genes involved in ethanol production (PDC genes and ADH1), in glycerol synthesis (GPD1 and HOR2), and in low-affinity hexose transporters (HXT1 and HXT3) were up-regulated at the beginning of model dough-fermentation. Among genes up-regulated at 15 min, several genes classified as transcription were down-regulated within 30 min. These down-regulated genes are involved in messenger RNA splicing and ribosomal protein biogenesis, in zinc finger transcription factor proteins, and in transcriptional regulator (SRB8, MIG1). In contrast, genes involved in amino acid metabolism and in vitamin metabolism, such as arginine biosynthesis, riboflavin biosynthesis, and thiamin biosynthesis, were subsequently up-regulated after 30 min. Interestingly, the genes involved in the unfolded protein response (UPR) pathway were also subsequently up-regulated. Our study presents the first overall description of the transcriptional response of baker’s yeast during dough-fermentation, and will thus help clarify genomic responses to various stresses during commercial fermentation processes. Keywords: fermentation
Project description:Commercial brewing yeast strains are exposed to a number of potential stresses including oxidative stress. The aim of this investigation was to measure the physiological and transcriptional changes of yeast cells during full-scale industrial brewing processes with a view to determining the environmental factors influencing the cell’s oxidative stress response. Cellular antioxidant levels were monitored throughout an industrial propagation and fermentation and microarray analysis was employed to determine transcriptional changes in antioxidant-encoding and other stress response genes. The greatest increase in cellular antioxidants and transcription of antioxidant-encoding genes occurred as the rapidly fermentable sugars glucose and fructose were depleted from the growth medium (wort) and the cell population entered the stationary phase. The data suggest that, contrary to expectation, the oxidative stress response is not influenced by changes in the dissolved oxygen concentration of wort but is initiated as part of a general stress response to growth-limiting conditions, even in the absence of oxygen. A mechanism is proposed to explain the changes in antioxidant response observed in yeast during anaerobic fermentation. The results suggest that the yeast cell does not experience oxidative stress, per se, during industrial brewery handling. This information may be taken into consideration when setting parameters for industrial brewery fermentation. Experimenter name: Brian Gibson Experimenter phone: +44 (0)1159516214 Keywords: time_series_design; fermentation
Project description:The fermentable carbohydrate composition of wort and the manner in which it is utilised by yeast during brewery fermentation has a direct influence on fermentation efficiency and quality of the finished product. In this study the response of a brewing yeast strain to changes in wort fermentable carbohydrate concentration and composition during full-scale (3275 hL) brewery fermentation was investigated by measuring transcriptome changes with the aid of oligonucleotide based DNA arrays. Up to 90% of the detectable genes showed a significant (P ≤ 0.05) differential expression pattern during fermentation and the majority of these genes showed either transient or prolonged peaks in expression following the exhaustion of the monosaccharides glucose and fructose from the wort. Those which did not display this apparent carbon catabolite derepression response were mainly those genes involved in cytokinesis and cell budding, which had higher expression values during active growth of cells. Transcriptional activity of many genes was consistent with their known responses to glucose de/repression under laboratory conditions, despite the presence of di- and trisaccharide sugars in the wort. Experimenter name: Katherine Smart Experimenter phone: 0044-1159516214 Experimenter address: School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire Experimenter zip/postal_code: LE12 5RD Experimenter country: England Keywords: time series design
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:Gene expression analysis of time course experiment of [1] a synthetic must (nitrogen-rich) fermentation by a natural wine yeast; [2] a synthetic must (nitrogen-poor) fermentation by a natural wine yeast; and [3] a synthetic must (nitrogen-poor) fermentation by a natural wine yeast, supplemented at 72 hours with 200 mg/l of nitrogen. This SuperSeries is composed of the following subset Series: GSE5835: Normal Fermentation GSE5836: Sluggish Fermentation GSE5837: Recovered Fermentation Keywords: SuperSeries Refer to individual Series, and to genomic hybridization of the individual membranes used for normalizing single samples.
Project description:Studying the genetic and molecular characteristics of brewing yeast strains is crucial for understanding their domestication history and adaptations accumulated over time in fermentation environments, and for guiding optimizations to the brewing process itself. Saccharomyces cerevisiae (brewing yeast) is amongst the most profiled organisms on the planet, yet the temporal molecular changes that underlie industrial fermentation and beer brewing remain understudied. Here, we characterized the genomic makeup of a Saccharomyces cerevisiae ale yeast widely used in the production of Hefeweizen beers, and applied shotgun mass spectrometry to systematically measure the proteomic changes throughout two fermentation cycles which were separated by 14 rounds of serial repitching.
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:Gene expression analysis of a time course experiment of a synthetic must (nitrogen-rich) fermentation by a natural wine yeast. Keywords: Time course
Project description:Gene expression analysis of a time course experiment of a synthetic must (nitrogen-poor) fermentation by a natural wine yeast. Keywords: Time course