Project description:Arsenic is known as a human carcinogen that easily be exposed by the living organisms through environment and food consumption. The arsenic is transport into the cells via phosphate transporters due to its structural similarity with phosphate in both prokaryotes and eukaryotes. We here evaluated and analyzed the toxicogenomic impacts of arsenate and the role of different phosphate concentrations on arsenic toxicity. Our results showed that arsenic uncoupled phosphate levels which eventually affected the growth rate of yeast cells. Analysis of arsenate levels in the medium over 4 to 10 h of its exposure clearly showed that arsenate was easily taken up by the cells in phosphate limited condition.
Project description:In industrial fermentations of Saccharomyces cerevisiae, transient changes in oxygen concentration commonly occur and it is important to understand the behaviour of cells during these changes. Saccharomyces cerevisiae CEN.PK113-1A was grown in glucose-limited chemostat culture with 1.0% and 20.9% O2 in the inlet gas (D= 0.10 /h, pH5, 30C). After steady state was achieved, oxygen was replaced with nitrogen and cultures were followed until new steady state was achieved. The overall responses to anaerobic conditions of cells initially in different conditions were very similar. Independent of initial culture conditions, transient downregulation of genes related to growth and cell proliferation, mitochondrial translation and protein import, and sulphate assimilation was seen. In addition, transient or permanent upregulation of genes related to protein degradation, and phosphate and amino acid uptake was observed in all cultures. However, only in the initially oxygen-limited cultures was a transient upregulation of genes related to fatty acid oxidation, peroxisomal biogenesis, oxidative phosphorylation, TCA cycle, response to oxidative stress, and pentose phosphate pathway observed. Furthermore, from the initially oxygen-limited conditions, a rapid response around the metabolites of upper glycolysis and the pentose phosphate pathway was seen, while from the initially fully aerobic conditions, a slower response around the pathways for utilisation of respiratory carbon sources was observed. Time series analysis starting from two (1% and 20.9%) levels of oxygen provision. Seven timepoints from both time series and two biological replicates from each timepoint were analysed.
Project description:In industrial fermentations of Saccharomyces cerevisiae, transient changes in oxygen concentration commonly occur and it is important to understand the behaviour of cells during these changes. Saccharomyces cerevisiae CEN.PK113-1A was grown in glucose-limited chemostat culture with 1.0% and 20.9% O2 in the inlet gas (D= 0.10 /h, pH5, 30C). After steady state was achieved, oxygen was replaced with nitrogen and cultures were followed until new steady state was achieved. The overall responses to anaerobic conditions of cells initially in different conditions were very similar. Independent of initial culture conditions, transient downregulation of genes related to growth and cell proliferation, mitochondrial translation and protein import, and sulphate assimilation was seen. In addition, transient or permanent upregulation of genes related to protein degradation, and phosphate and amino acid uptake was observed in all cultures. However, only in the initially oxygen-limited cultures was a transient upregulation of genes related to fatty acid oxidation, peroxisomal biogenesis, oxidative phosphorylation, TCA cycle, response to oxidative stress, and pentose phosphate pathway observed. Furthermore, from the initially oxygen-limited conditions, a rapid response around the metabolites of upper glycolysis and the pentose phosphate pathway was seen, while from the initially fully aerobic conditions, a slower response around the pathways for utilisation of respiratory carbon sources was observed.
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
Project description:This study explores the connection between changes in gene expression and the genes that determine strain survival during suspension culture, using the model eukaryotic organism, Saccharomyces cerevisiae. The Saccharomyces cerevisiae homozygous diploid deletion pool, and the BY4743 parental strain were grown for 18 hours in a rotating wall vessel, a suspension culture device optimized to minimize the delivered shear. In addition to the reduced shear conditions, the rotating wall vessels were also placed in a static position or in a shaker in order to change the amount of shear stress on the cells. Keywords: shear stress, time course
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.
Project description:Transription profile of Saccharomyces cerevisiae SK1 cultures undergoing synchronous sporulation. We have measured mRNA levels in synchronized SK1 cells immediately upon transfer to the sporulation medium and every 30 minutes after that for 6 hours. mRNA extracted from these cultures were converted to cDNA and hybridized to microarrays and log2 ratios of hybridization signal of each time point was compared to that of time zero (immediately prior to transfer to the sporulation medium). Keywords: Time course