Global transcriptional machinery engineering in E. coli in the presence and absence of ethanol
Ontology highlight
ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE3665 | GEO | 2007/09/23
SECONDARY ACCESSION(S): PRJNA93799
REPOSITORIES: GEO
Similar Datasets
Project description:We measured transcriptional changes in an effort to understand mechanisms of action resulting from the introduction of global transcriptional machinery engineering in E. coli in the presence and absence of ethanol. Experiment Overall Design: We explored two types of experimental factors: genetic variation (mutated transcriptional machinery) and environmental variation (ethanol concentration).
2008-06-12 | E-GEOD-3665 | biostudies-arrayexpress
Project description:Global transcription machinery engineering (gTME) is an approach for reprogramming gene transcription to elicit cellular phenotypes important for technological applications. Here we show the application of gTME to Saccharomyces cerevisiae for improved glucose/ethanol tolerance, a key trait for many biofuels programs. Mutagenesis of the transcription factor Spt15p and selection led to dominant mutations that conferred increased tolerance and more efficient glucose conversion to ethanol. The desired phenotype results from the combined effect of three separate mutations in the SPT15 gene [serine substituted for phenylalanine (Phe177Ser) and, similarly, Tyr195His, and Lys218Arg]. Thus, gTME can provide a route to complex phenotypes that are not readily accessible by traditional methods. Keywords: stress response
2006-11-30 | GSE5185 | GEO
Project description:Evolutionary engineering strategy was used for selection of ethanol-tolerant Saccharomyces cerevisiae clones under gradually increasing ethanol stress levels. Clones B2 and B8 were selected based on their higher ethanol-tolerance and higher ethanol production levels. Whole genome microarray analysis was used for identifying the gene expression levels of these two evolved clones compared to the reference strain.
2016-03-01 | GSE78759 | GEO
Project description:Evolutionary engineering strategy was used for selection of ethanol-tolerant Saccharomyces cerevisiae clones under gradually increasing ethanol stress levels. Clones B2 and B8 were selected based on their higher ethanol-tolerance and higher ethanol production levels. Whole genome microarray analysis was used for identifying the gene expression levels of these two evolved clones compared to the reference strain. Two evolved ethanol-tolerant strains B2 and B8, which were selected by evolutionary engineering under gradually increasing ethanol stress, were used for whole genome transcriptomic analysis in comparison with the reference strain. Cells were grown in yeast minimal media until they reach a final OD600 of 1. Following total RNA isolation, gene expression levels were analyzed using One-color microarray-based gene expression analysis (Agilent Technologies). Experiments were done in triplicates.
2016-03-01 | E-GEOD-78759 | biostudies-arrayexpress
Project description:Cellular tolerance toward ethanol is a complex phenotype involved many genes, and hard to be improved by manipulating individual genes. We previously established exogenous global regulator IrrE mutants that confer Escherichia coli with significantly enhanced tolerance to stresses, including ethanol. In order to elucidate the mechanism for enhancement of ethanol tolerance in the mutants and to identify new genes and pathways that can be possible targets for engineering of ethanol tolerance, we carried out comparative transcriptomic and proteomic analyses with the representative strains E1 and E0 (harboring the ethanol-tolerant mutant E1 of IrrE and the wild type IrrE, respectively). The data from transcriptome analyses were deposited here.
2012-05-01 | GSE30441 | GEO
Project description:Cellular tolerance toward ethanol is a complex phenotype involved many genes, and hard to be improved by manipulating individual genes. We previously established exogenous global regulator IrrE mutants that confer Escherichia coli with significantly enhanced tolerance to stresses, including ethanol. In order to elucidate the mechanism for enhancement of ethanol tolerance in the mutants and to identify new genes and pathways that can be possible targets for engineering of ethanol tolerance, we carried out comparative transcriptomic and proteomic analyses with the representative strains E1 and E0 (harboring the ethanol-tolerant mutant E1 of IrrE and the wild type IrrE, respectively). The data from transcriptome analyses were deposited here. Cells of ethanol-tolerant mutant E1 and wild-type strain E0 were grown in 1.5% ethanol, and the samples for both of these two strains were prepared in triplicate with biological replicates
2012-04-30 | E-GEOD-30441 | biostudies-arrayexpress
Project description:Sucrose is a major carbon source for industrial bioethanol production by Saccharomyces cerevisiae. In yeasts, two modes of sucrose metabolism occur: (i) extracellular hydrolysis by invertase, followed by uptake and metabolism of glucose and fructose, and (ii) uptake via sucrose-H+ symport followed by intracellular hydrolysis and metabolism. Although alternative start codons in the SUC2 gene enable synthesis of extracellular and intracellular invertase isoforms, sucrose hydrolysis in S. cerevisiae predominantly occurs extracellularly. In anaerobic cultures, intracellular hydrolysis theoretically enables a 9 % higher ethanol yield than extracellular hydrolysis, due to energy costs of sucrose-proton symport. This prediction was tested by engineering the promoter and 5’ coding sequences of SUC2, resulting in relocation of invertase to the cytosol. In anaerobic sucrose-limited chemostats, this iSUC2-strain showed an only 4% increased ethanol yield and high residual sucrose concentrations indicated suboptimal sucrose-transport kinetics. To improve sucrose-uptake affinity, it was subjected to 95 generations of anaerobic, sucrose-limited chemostat cultivation, resulting in a 20-fold decrease of residual sucrose concentrations and a 10-fold increase of the sucrose-transport capacity. A single-cell isolate showed an 11 % higher ethanol yield on sucrose in chemostat and batch cultures than an isogenic SUC2 reference strain, while transcriptome analysis revealed elevated expression of AGT1, encoding a disaccharide-proton symporter, and other maltose-related genes. Deletion of AGT1, which had been duplicated during laboratory evolution, restored the growth characteristics of the unevolved iSUC2 strain. This study demonstrates that engineering the topology of sucrose metabolism is an attractive strategy to improve ethanol yields in industrial processes.
2011-09-06 | GSE30535 | GEO
Project description:Sucrose is a major carbon source for industrial bioethanol production by Saccharomyces cerevisiae. In yeasts, two modes of sucrose metabolism occur: (i) extracellular hydrolysis by invertase, followed by uptake and metabolism of glucose and fructose, and (ii) uptake via sucrose-H+ symport followed by intracellular hydrolysis and metabolism. Although alternative start codons in the SUC2 gene enable synthesis of extracellular and intracellular invertase isoforms, sucrose hydrolysis in S. cerevisiae predominantly occurs extracellularly. In anaerobic cultures, intracellular hydrolysis theoretically enables a 9 % higher ethanol yield than extracellular hydrolysis, due to energy costs of sucrose-proton symport. This prediction was tested by engineering the promoter and 5’ coding sequences of SUC2, resulting in relocation of invertase to the cytosol. In anaerobic sucrose-limited chemostats, this iSUC2-strain showed an only 4% increased ethanol yield and high residual sucrose concentrations indicated suboptimal sucrose-transport kinetics. To improve sucrose-uptake affinity, it was subjected to 95 generations of anaerobic, sucrose-limited chemostat cultivation, resulting in a 20-fold decrease of residual sucrose concentrations and a 10-fold increase of the sucrose-transport capacity. A single-cell isolate showed an 11 % higher ethanol yield on sucrose in chemostat and batch cultures than an isogenic SUC2 reference strain, while transcriptome analysis revealed elevated expression of AGT1, encoding a disaccharide-proton symporter, and other maltose-related genes. Deletion of AGT1, which had been duplicated during laboratory evolution, restored the growth characteristics of the unevolved iSUC2 strain. This study demonstrates that engineering the topology of sucrose metabolism is an attractive strategy to improve ethanol yields in industrial processes. The goal of the present study was to investigate whether a relocation of sucrose hydrolysis to the cytosol can be used to improve ethanol yields on sucrose and which additional steps may be required to improve sucrose utilization by strains that only express intracellular invertase. To this end, the SUC2 gene was modified to cause an exclusive intracellular localization. Growth and product formation by the engineered strain were compared with that of the parental strain in anaerobic sucrose-limited chemostat cultures. Subsequently, evolutionary engineering was used to improve sucrose uptake kinetics and an evolved strain was characterized for growth and product formation in chemostat cultures. Transcriptome analysis and gene deletion studies were used to identify genetic changes in the evolved strain that contribute to its improved sucrose-uptake kinetics.
2011-09-05 | E-GEOD-30535 | biostudies-arrayexpress
Project description:The expression levels of uropathogenic E. coli (UPEC) UTI89 cells in YESCA broth with and without 4% dimehtyl sulfoxide (DMSO) and 2% ethanol (EtOH) were studied.
2012-02-15 | GSE35797 | GEO
Project description:The molecular mechanisms of ethanol toxicity and tolerance in bacteria, while important for biotechnology and bioenergy applications, remain incompletely understood. Genetic studies have identified potential cellular targets for ethanol and revealed multiple mechanisms of tolerance, but it remains difficult to separate direct and indirect effects of ethanol. We used adaptive evolution to generate spontaneous ethanol-tolerant strains of Escherichia coli, then characterized the mechanisms of toxicity and resistance associated with select mutations. Evolved alleles of metJ, rho, and rpsQ were sufficient to recapitulate much of the observed ethanol tolerance, implicating translation and transcription as key processes affected by ethanol. We found that ethanol induces mistranslation errors during protein synthesis, and that the evolved rpsQ allele protects cells by rendering the ribosome hyper-accurate. Ribosome profiling and RNAseq analyses of the ethanol-tolerant strain versus the wild type established that ethanol negatively affects transcriptional and translational processivity. Ethanol-stressed cells exhibited ribosomal stalling at internal AUG codons, which may be ameliorated by the adaptive inactivation of the MetJ repressor of methionine biosynthesis genes. Ethanol also caused aberrant intragenic transcription termination for mRNAs with low ribosome density, which was reduced in a strain with the adaptive rho mutation. Furthermore, ethanol inhibited transcript elongation by RNA polymerase in vitro. We propose that ethanol-induced inhibition and uncoupling of mRNA and protein synthesis are major contributors to ethanol toxicity in E. coli, and that adaptive mutations in metJ, rho, and rpsQ protect central dogma processes in the presence of ethanol.
2014-06-18 | GSE56407 | GEO