Saccharomyces cerevisiae
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ABSTRACT:
PROVIDER: PRJNA99669 | ENA |
REPOSITORIES: ENA
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Project description:When the yeast Saccharomyces cerevisiae is subjected to increasing glycolytic fluxes under aerobic conditions, there is a threshold value of the glucose uptake rate at which the metabolism shifts from being purely respiratory to mixed respiratory and fermentative. This shift is characterized by ethanol production, a phenomenon known as the Crabtree effect due to its analogy with lactate overflow in cancer cells. It is well known that at high glycolytic fluxes there is glucose repression of respiratory pathways resulting in a decrease in the respiratory capacity. Despite many years of detailed studies on this subject, it is not known whether the onset of the Crabtree effect (or overflow metabolism) is due to a limited respiratory capacity or caused by glucose-mediated repression of respiration. We addressed this issue by increasing respiration in S. cerevisiae by introducing a heterologous alternative oxidase, and observed reduced aerobic ethanol formation. In contrast, increasing non-respiratory NADH oxidation by overexpression of a water-forming NADH oxidase reduced aerobic glycerol formation. The metabolic response to elevated alternative oxidase occurred predominantly in the mitochondria, while NADH oxidase affected genes that catalyze cytosolic reactions. Moreover, NADH oxidase restored the deficiency of cytosolic NADH dehydrogenases in S. cerevisiae. These results indicate that NADH oxidase localizes in the cytosol, while alternative oxidase is directed to the mitochondria. The onset of aerobic ethanol formation is demonstrated to be a consequence of an imbalance in mitochondrial redox balancing. In addition to answering fundamental physiological questions, our findings are relevant for all biomass derived applications of S. cerevisiae. Keywords: Genetic Modification
2007-02-01 | GSE6277 | GEO
Project description:When the yeast Saccharomyces cerevisiae is subjected to increasing glycolytic fluxes under aerobic conditions, there is a threshold value of the glucose uptake rate at which the metabolism shifts from being purely respiratory to mixed respiratory and fermentative. This shift is characterized by ethanol production, a phenomenon known as the Crabtree effect due to its analogy with lactate overflow in cancer cells. It is well known that at high glycolytic fluxes there is glucose repression of respiratory pathways resulting in a decrease in the respiratory capacity. Despite many years of detailed studies on this subject, it is not known whether the onset of the Crabtree effect (or overflow metabolism) is due to a limited respiratory capacity or caused by glucose-mediated repression of respiration. We addressed this issue by increasing respiration in S. cerevisiae by introducing a heterologous alternative oxidase, and observed reduced aerobic ethanol formation. In contrast, increasing non-respiratory NADH oxidation by overexpression of a water-forming NADH oxidase reduced aerobic glycerol formation. The metabolic response to elevated alternative oxidase occurred predominantly in the mitochondria, while NADH oxidase affected genes that catalyze cytosolic reactions. Moreover, NADH oxidase restored the deficiency of cytosolic NADH dehydrogenases in S. cerevisiae. These results indicate that NADH oxidase localizes in the cytosol, while alternative oxidase is directed to the mitochondria. The onset of aerobic ethanol formation is demonstrated to be a consequence of an imbalance in mitochondrial redox balancing. In addition to answering fundamental physiological questions, our findings are relevant for all biomass derived applications of S. cerevisiae. Experiment Overall Design: Heterologous gene expression in chemostats using Affymetrix Yeast Genome 2.0 arrays. Total RNA extraction and sample preparation, hybridization was done according to the manufacturer's protocol.
2008-06-14 | E-GEOD-6277 | biostudies-arrayexpress
Project description:Saccharomyces spp. are widely used for ethanol production however fermentation productivity is negatively affected by the impact of ethanol accumulation on yeast metabolic rate and viability. This study used microarray and statistical two-way ANOVA analysis to compare and evaluate gene expression profiles of two previously generated ethanol-tolerant mutants, CM1 and SM1, with their parent, S. cerevisiae W303-1A, in the presence and absence of ethanol stress. Although sharing the same parentage, the mutants were created differently; SM1 by adaptive evolution involving long-term exposure to ethanol stress, and CM1 using chemical mutagenesis followed by adaptive evolution-based screening. Compared to the parent, differences in the expression levels of genes associated with a number of GO categories in the mutants suggest that their improved ethanol stress response is a consequence of increased mitochondrial and NADH oxidation activities, stimulating glycolysis and energy production. This leads to increased activity of energy-demanding processes associated with the production of proteins and plasma membrane components, which are necessary for acclimation to ethanol stress. It is suggested that a key function of the ethanol stress response is restoration of the NAD+/NADH redox balance, which increases glyceraldehyde-3-phosphate dehydrogenase activity, and higher glycolytic flux in the ethanol-stressed cell. Both mutants achieved this by a constitutive increase in carbon flux in the glycerol pathway as a means of increasing NADH oxidation.
2010-07-01 | GSE21120 | GEO
Project description:Response of Saccharomyces cerevisiae engineered for xylose metabolism to changes in carbon source and aeration Keywords: ordered
2004-11-13 | GSE835 | GEO
Project description:Investigation of Saccharomyces cerevisiae phosphate metabolism. Cells starved for phosphate, cells grown with intermediate and high phosphate concentrations, and PHO4 mutant cells examined. Keywords: other
2003-08-29 | GSE603 | GEO
Project description:Phosphate metabolism in Saccharomyces cerevisiae
| PRJNA85403 | ENA
Project description:Saccharomyces cerevisiae is an excellent microorganism for industrial succinic acid production, but high succinic acid concentration will inhibit the growth of Saccharomyces cerevisiae then reduce the production of succinic acid. Through analysis the transcriptomic data of Saccharomyces cerevisiae with different genetic backgrounds under different succinic acid stress, we hope to find the response mechanism of Saccharomyces cerevisiae to succinic acid.
2022-01-09 | GSE193190 | GEO
Project description:Saccharomyces spp. are widely used for ethanol production however fermentation productivity is negatively affected by the impact of ethanol accumulation on yeast metabolic rate and viability. This study used microarray and statistical two-way ANOVA analysis to compare and evaluate gene expression profiles of two previously generated ethanol-tolerant mutants, CM1 and SM1, with their parent, S. cerevisiae W303-1A, in the presence and absence of ethanol stress. Although sharing the same parentage, the mutants were created differently; SM1 by adaptive evolution involving long-term exposure to ethanol stress, and CM1 using chemical mutagenesis followed by adaptive evolution-based screening. Compared to the parent, differences in the expression levels of genes associated with a number of GO categories in the mutants suggest that their improved ethanol stress response is a consequence of increased mitochondrial and NADH oxidation activities, stimulating glycolysis and energy production. This leads to increased activity of energy-demanding processes associated with the production of proteins and plasma membrane components, which are necessary for acclimation to ethanol stress. It is suggested that a key function of the ethanol stress response is restoration of the NAD+/NADH redox balance, which increases glyceraldehyde-3-phosphate dehydrogenase activity, and higher glycolytic flux in the ethanol-stressed cell. Both mutants achieved this by a constitutive increase in carbon flux in the glycerol pathway as a means of increasing NADH oxidation. Two conditions: 0% and 6.5 % (v/v) ethanol added to the culture growth medium for each strain. One set of triplicates with one dye swap for each condition. Each triplicate was prepared from different biological replicate (i.e. different culture).
2010-07-01 | E-GEOD-21120 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the following subset Series: GSE34808: A transcriptomic analysis of the response of Saccharomyces cerevisiae to increases in NADPH oxidation [2009] GSE34809: A transcriptomic analysis of the response of Saccharomyces cerevisiae to increases in NADPH oxidation [2010] Refer to individual Series
2012-03-31 | E-GEOD-34810 | biostudies-arrayexpress
Project description:Xylose metabolism in recombinant Saccharomyces cerevisiae
| PRJNA110883 | ENA