Project description:Metabolomic profiles were compiled from oak and wine yeast parents over three extraction times (batch). Included in this study are extraction controls.
Project description:Metabolomic profiles were compiled from reciprocal hemizygotes (oak/win hybrid, genes AUA1, ARG82) (batch). Included in this study are extraction controls.
Project description:Second fermentation in a bottle supposes such specific conditions that undergo yeasts to a set of stress situations like high ethanol, low nitrogen, low pH or sub-optimal temperature. Also, yeast have to grow until 1 or 2 generations and ferment all sugar available while they resist increasing CO2 pressure produced along with fermentation. Because of this, yeast for second fermentation must be selected depending on different technological criteria such as resistance to ethanol, pressure, high flocculation capacity, and good autolytic and foaming properties. All of these stress factors appear sequentially or simultaneously, and their superposition could amplify their inhibitory effects over yeast growth. Considering all of the above, it has supposed interesting to characterize the adaptive response of commercial yeast strain EC1118 during second-fermentation experiments under oenological/industrial conditions by transcriptomic profiling. We have pointed ethanol as the most relevant environmental condition in the induction of genes involved in respiratory metabolism, oxidative stress, autophagy, vacuolar and peroxisomal function, after comparison between time-course transcriptomic analysis in alcoholic fermentation and transcriptomic profiling in second fermentation. Other examples of parallelism include overexpression of cellular homeostasis and sugar metabolism genes. Finally, this study brings out the role of low-temperature on yeast physiology during second-fermentation.
Project description:Effect of FLO8 or MSS11 deletion and -overexpression on yeast transcript profiles compared to wild type in laboratory yeast strains Σ1278b and S288c.
Project description:Second fermentation in a bottle supposes such specific conditions that undergo yeasts to a set of stress situations like high ethanol, low nitrogen, low pH or sub-optimal temperature. Also, yeast have to grow until 1 or 2 generations and ferment all sugar available while they resist increasing CO2 pressure produced along with fermentation. Because of this, yeast for second fermentation must be selected depending on different technological criteria such as resistance to ethanol, pressure, high flocculation capacity, and good autolytic and foaming properties. All of these stress factors appear sequentially or simultaneously, and their superposition could amplify their inhibitory effects over yeast growth. Considering all of the above, it has supposed interesting to characterize the adaptive response of commercial yeast strain EC1118 during second-fermentation experiments under oenological/industrial conditions by transcriptomic profiling. We have pointed ethanol as the most relevant environmental condition in the induction of genes involved in respiratory metabolism, oxidative stress, autophagy, vacuolar and peroxisomal function, after comparison between time-course transcriptomic analysis in alcoholic fermentation and transcriptomic profiling in second fermentation. Other examples of parallelism include overexpression of cellular homeostasis and sugar metabolism genes. Finally, this study brings out the role of low-temperature on yeast physiology during second-fermentation. S. cerevisiae EC1118 pre-adapted to ethanol cells and sucrose (20 g/L) were added to 20 L of base wine (Cavas Freixenet, Sant Sadurní D’Anoia, Spain). Complete volume was bottled with 350 mL each one. All were sealed and incubated in static conditions at 16ºC for approximately 40 days after tirage. Three samples were taken during the process for transcriptional study of the physiological adaptation of yeast cells to industrial second fermentation conditions. A sample corresponding to exponential-growth phase under unstressed conditions (in YPD at 28ºC) was used as an external reference. Three timepoints from second-fermentation were monitored and three biological replicates from each timepoint were analyzed.
Project description:Reprogramming a non-methylotrophic industrial host, such as Saccharomyces cerevisiae, to a synthetic methylotroph reprents a huge challenge due to the complex regulation in yeast. Through TMC strategy together with ALE strategy, we completed a strict synthetic methylotrophic yeast that could use methanol as the sole carbon source. However, how cells respond to methanol and remodel cellular metabolic network on methanol were not clear. Therefore, genome-scale transcriptional analysis was performed to unravel the cellular reprograming mechanisms underlying the improved growth phenotype.
Project description:Effect of either FLO8 or MSS11 deletion and -overexpression on yeast transcript profiles compared to wild type in laboratory yeast strains Σ1278b and S288c - also the effect of FLO11 (MUC1) overexpression in the Σ1278b genetic background The aim of this study was to (1) perform a repeat analysis (to improve statistical analysis of these data sets) similar to data submitted previously (GSE17716) and also (2) study the effect of FLO11 over-expression on the transcriptome. Background: The outer cell wall of the yeast Saccharomyces cerevisiae serves as the interface with the surrounding environment and defines cell-cell and cell-surface interactions. Many of these interactions are facilitated by specific adhesins that belong to the Flo protein family. This family of mannoproteins has been implicated in phenotypes such as flocculation and substrate adhesion as well as pseudohyphal growth. Genetic data strongly suggest that individual Flo proteins are responsible for many specific cellular adhesion phenotypes. However, it remains unclear whether such phenotypes are determined solely by the nature of the expressed FLO genes or rather the result of a combination of FLO gene expression and other cell wall properties and cell wall proteins. Mss11p has been shown to be a central element of FLO1 and FLO11 gene regulation and acts together with the cAMP-PKA-dependent transcription factor Flo8p. We use genome wide transcript analysis to identify genes that are direct ly or indirectly regulated by Mss11p in the genetic backgrounds: Sigma1278b and S288c. Sigma 1278b is the strain historically used for the study of pseudohyphae (FLO11 expression) but we also included S288c as this strain is widely used in the research community and was used to determine the first full genome sequence (Thus correspond with SGD information). We also compare this data with transcriptome data from Sigma 1278b yeast over-expressing FLO8 to compare similarities/differences between these two signalling factors. Finally the effect of FLO11 over-expression in Sigma1278b on global transcription is studied so that we can differentiate between "direct" gene targets of Flo8p or Mss11p, and those regulated as a result by the "indirect" effect caused by modified cell wall Flo11p levels.
Project description:Oxidative stress is a harmful condition in a cell, tissue, or organ, caused by an imbalnace between reactive oxygen species and other oxidants and the capacity of antioxidant defense systems to remove them. The budding yeast S. cerevisiae has been the major eukaryotic model for studies of response to oxidative stress. We used microarrays to study the genome-wide temporal response of the yeast S. cerevisiae to oxidative stress induced by cumene hydroperoxide. Keywords: time course The effects of oxidative stress induced by CHP on the transcriptional profile of S. cerevisiae was studied from a dynamical perspective. Yeast cultures were grown in controlled batch conditions, in 1 L fermentors. Three replicate cultures in mid-exponential phase were exposed to 0.19 mM CHP, while three non-treated cultures were used as controls. Samples were collected at t=0 (immediately before adding CHP) and at 3, 6, 12 and 20 min after adding the oxidant. Samples were processed for RNA extraction and profiled using Affymetrix Yeast Genome S98 arrays.