Unknown,Transcriptomics,Genomics,Proteomics

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Transcriptomic reprogramming of Ethanol adapted vs Ethanol non adapted culture

ABSTRACT: We have previously shown that fed-batch processes with the longest uncoupling phase (ethanol adapted) were characterized by induction of storage carbohydrates, a metabolic event typical of yeast cells experiencing nutrient limitation, at the onset of this phase, whereas this metabolic event was not seen in processes with a short uncoupling phase (ethanol non adapted culture). Taken together, our results suggested that reproducible high bioethanol performance in aerated fed-batch process may be linked to the ability of yeast cells to impede ethanol toxicity by triggering a metabolic remodelling reminiscent to that of cells entering a quiescent G0/G1 state. The aim of this study was to search for genes implicated in the induction an ethanol adapted culture vs ethanol non-adapted culture. We measure the changes in the gene expression of Ethanol adapted culture (Test : fermentation I in ref 17005001[PMID]) and Ethanol non-adapted (reference : Fermentation II in ref 17005001[PMID]) at the same ethanol concentration of 60 g/l and the same growth rate of the cells (0,14 h-1 :Test) and (0,13 h-1 : reference) to reduce the risk of observing secondary effects due to growth and ethanol stress. For each sample, total RNAs from one yeast culture (no biological replicate) were extracted four times (technical replicates -extract). For labelling, we employed a dye-switch (dCTP-Cy3 and dCTP-Cy5) repeated 2 times and hybridized cDNA on four independent microarrays, given rise to eight data value per gene (each gene is duplicate on the slide).

ORGANISM(S): Saccharomyces cerevisiae

SUBMITTER: Laurent Benbadis

PROVIDER: E-GEOD-15321 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Physiological behaviour of Saccharomyces cerevisiae in aerated fed-batch fermentation for high level production of bioethanol.

Cot Marlène M Loret Marie-Odile MO François Jean J Benbadis Laurent L

FEMS yeast research 20060928 1

Saccharomyces cerevisiae was able to produce 20% (v/v) of ethanol in 45 h in a fully aerated fed-batch process recently developed in our laboratory. A notable feature of this process was a production phase uncoupled to growth, the extent of which was critical for high-level ethanol production. As the level of production was found to be highly variable, we investigated on this high variability by means of a detailed physiological analysis of yeast cells in two fed-batch fermentations showing the ...[more]

PMID: 17005001

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Project description:The yeast Saccharomyces cerevisiae is well known for its high ethanol production performances. An original fermentation process that allows the yeast S. cerevisiae to produce in less than 45 h more than 150 g/l ethanol (i.e. 18.9°GL) was set up in our laboratory [1]. Under this condition, the yeast cells induce a dynamic process to adapt to increased ethanol concentration by a mechanism that is likely different to the stress response triggered by sudden ethanol addition to exponentially growing cells [2]. Kinetic analysis of the growth curve identified two main phases: a growth phase that ended up at 90 g/l ethanol and then an uncoupling phase during which non-growing cells kept producing ethanol. This latter phase is also characterized with an increased loss of viability. In order to investigate on a genome scale the expression changes occurring during this process, gene expression was quantified using DNA chips technology at six different time-points during fed-batch fermentation. [1] Alfenore et al, Appl. Microbiol. Biotechnol. 60 : 67-72, 2002. [2] Alexandre H. et al., FEBS Lett. 498(1) : 98-103, 2001. We measure the changes in the gene expression of ethanol stressed culture at five different time-points during fed-batch fermentation compared to a common reference consisting of exponentially growing yeast cells ( sample number 1 : growing cells ; low ethanol concentration of 17 g/l ; specific growth rate of 0.3 h-1) . The sets corresponded to sample number 2 : growing cells/ethanol concentration of 60 g/l ; sample number 3 : before growth arrest/ethanol concentration of 90 g/l ; sample number 4 : growth arrest/ethanol concentration of 95 g/l ; sample number 5 : 1 hour after growth arrest/ethanol concentration of 100 g/l and sample number 6 : uncoupling phase/ethanol concentration of 125 g/l. For each sample, total RNAs from one yeast culture (no biological replicate) were extracted three times (technical replicates -extract). For labelling, we labelled the common reference with dCTP-Cy5 and labelled the sample with dCTP-Cy3 and hybridized cDNA on three independent microarrays, given rise to six data value per gene (each gene is duplicate in the slide).

Project description:We evaluated if a higher plane of maternal nutrition during late gestation and weaning age alters the offspringM-bM-^@M-^Ys Longissimus muscle (LM) transcriptome. A microarray analysis was performed in LM samples of early (EW) and normal weaned (NW) Angus M-CM-^W Simmental calves born from cows that were grazing endophyte-infected tall fescue/red clover pastures with no supplement (low plane of nutrition (LPN)), or supplemented with 2.3 kg of dried distillerM-bM-^@M-^Ys grains with solubles and soyhulls (70% DDGS/30% soyhulls) (medium plane of nutrition (MPN)) during the last 90 days of gestation. Biopsies were harvested at 78, 187 and 354 days of age. Bioinformatics analysis highlighted that offspring transcriptome did not respond markedly to cow plane of nutrition, resulting in only 13 differentially expressed genes. However, weaning age and a high-starch diet strongly impacted the transcriptome, especially the immediate activation of the lipogenic program in EW steers. In addition, between 78 and 187 days of age, these animals had an activation of the innate immune system due presumably to macrophage infiltration in intramuscular fat. Between 187 and 354 days of age (i.e. the fattening phase), NW steers had an activation of the lipogenic transcriptome machinery, while EW steers had a clear gene transcription inhibition. The latter appears to have occurred through the epigenetic control of histone acetylases, which were down-regulated. Higher cow plane of nutrition alone affected 35 genes in the LM of steers that underscore the presence of a mechanism of macrophage infiltration likely originating from localized oxidative stress as a result of increased levels of hypoplasia and hypertrophy in LM. A subset of 20 Angus x Simmental beef cows from the University of Illinois Dixon Springs Agriculture Center (DSAC) in Simpson, IL, were selected from a group of animals utilized in a parallel study75. Main effects evaluated were maternal plane of nutrition during late gestation and postnatal management of the offspring. Three months prior to the projected parturition date cows were assigned to treatments (low or medium plane of nutrition) in a split-plot design. Low plane of nutrition (LPN) was achieved by grazing endophyte-infected tall fescue/red clover pastures during July, August, and September with no supplement. Medium plane of nutrition cow diet (MPN) was achieved by grazing endophyte-infected tall fescue/red clover pastures supplemented with 2.3 kg of dried distillerM-bM-^@M-^Ys grains with solubles and soyhulls (70% DDGS/30% soyhulls). Angus x Simmental steer calves were randomly assigned to early or normal weaning treatments within each gestational treatment. This allowed for 10 animals for each postnatal treatment and 5 animals of each of the interactions of gestational M-CM-^W postnatal treatments. At 78 M-BM-1 2 days postpartum, early-wean offspring were weaned, transported to Urbana Beef Unit, and adapted to a high-starch diet until they had ad libitum consumption. At 187 M-BM-1 2 days postpartum, normal-wean offspring were weaned and transported to Urbana Beef Unit. All offspring were co-mingled among treatments. LM biopsies were sampled from a subset of 5 animals per gestational M-CM-^W postnatal treatment at time of early weaning (~78 days) and at time of normal weaning (~187 days), and during the last week prior to harvest (~ 354 days). After normal weaning, all offspring were placed on a common, corn grain-based high-starch finishing diet that is typical of industry management (CP% = 18.1, NDF% = 25.3, ADF% = 14.3, crude fat % = 5.1). All the offspring in the study were harvested at a commercial packing plant when they reached the selected end point target back fat thickness of 1.1 cm. Reported final body weight (BW) was calculated from hot carcass weight using a 62% dressing percentage. In the present study, we used a transcriptome-wide bovine microarray (Agilent-015354 Bovine Oligo Microarray-4x44K) that contains 21,475 unique genes and transcripts of Bos Taurus, with two probes per gene. The methods used for hybridization and scanning were according to manufacturerM-bM-^@M-^Ys protocols and Loor et al45. The microarray data were deposited in the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database (http://www.ncbi.nlm.nih.gov/gds) with accession number GSE-XXXX. GeneSpring GX (Agilent Technologies) was used for data visualization and preliminary data mining. Subsequently, the entire microarray data set with associated statistical P-values were imported into Ingenuity Pathways Analysis M-BM-. (IPA, www.ingenuity.com) in order to examine the number of activated and inhibited differentially expressed genes (DEG). Entrez Gene IDs were used to identify individual sequences. Data from the microarray analysis were normalized for dye and microarray effects (i.e., Lowess normalization and array centering) and used for statistical analysis. The MIXED procedure of SAS (SAS Institute, Inc., Cary, NC, USA) was used for statistical analysis. Fixed effects were treatment (early weaning, normal weaning), diet (low and medium cow plane of nutrition), time (78, 187, and 354 days of age), first, second and third order interactions between diet, time and treatment, and dye (Cy3, Cy5) and random effects included steer and microarray. Raw P values were adjusted using Benjamini and HochbergM-bM-^@M-^Ys false discovery rate (FDR). Bioinformatics analysis of microarray data was performed using DIA 10 and information from the freely-available online databases Kyoto Encyclopedia of Genes and Genomes (KEGG) and Database for Annotation, Visualization, and Integrated Discovery (DAVID) v6.7 databases. A list of gene identifiers (Entrez Gene IDs) was uploaded all at once to extract and summarize functional annotations associated with groups of genes or with each individual gene. The significance value associated with biological processes and pathways is a measure of the likelihood that the distribution of DEG in these pathways and biological processes is due to chance. The significance is expressed as a P-value, which is calculated using the right-tailed Fisher's Exact Test and adjusted using FDR. Details of the DIA approach and its validation have been reported previously. The interpretation of the bioinformatics analysis was performed following the same approach as our previous study.

Dataset Information

Transcriptomic reprogramming of Ethanol adapted vs Ethanol non adapted culture

Publications

Physiological behaviour of Saccharomyces cerevisiae in aerated fed-batch fermentation for high level production of bioethanol.

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