Project description:Reactive oxygen species, generated in vivo or exogenously encountered, constantly challenge living organisms. Oxidation of polyunsaturated fatty acids (PUFA), which are susceptible to oxidant attack, can lead to initiation of lipid peroxidation and in turn rapid production of toxic lipid hydroperoxides. Eukaryotic microorganisms such as Saccharomyces cerevisiae can survive harsh industrial conditions that contain high levels of the PUFA linoleic acid and its oxidised derivative, linoleic acid hydroperoxide (LoaOOH). The precise signalling and response mechanisms induced by yeast to overcome lipid hydroperoxide stress are ill understood. We used genome-wide microarrays to investigate the changes in gene expression of S. cerevisiae to LoaOOH-induced oxidative stress.
Project description:Reactive oxygen species, generated in vivo or exogenously encountered, constantly challenge living organisms. Oxidation of polyunsaturated fatty acids (PUFA), which are susceptible to oxidant attack, can lead to initiation of lipid peroxidation and in turn rapid production of toxic lipid hydroperoxides. Eukaryotic microorganisms such as Saccharomyces cerevisiae can survive harsh industrial conditions that contain high levels of the PUFA linoleic acid and its oxidised derivative, linoleic acid hydroperoxide (LoaOOH). The precise signalling and response mechanisms induced by yeast to overcome lipid hydroperoxide stress are ill understood. We used genome-wide microarrays to investigate the changes in gene expression of S. cerevisiae to LoaOOH-induced oxidative stress. S. cerevisiae (BY4743) were exposed to an arresting concentration of LoaOOH (75 M-BM-5M) for 1 hr to induce oxidative stress. Yeast treated with an equivalent volume of solvent (methanol) were used as a control. Following treatment conditions, total RNA was extracted from LoaOOH-treated or control yeast and hybridised onto Affymetrix microarrays.
Project description:Oxidative stress is experienced by all aerobic organisms and results in cellular damage. The damage caused during oxidative stress is particular to the oxidant challenge faced, and so too is the induced stress response. The eukaryote Saccharomyces cerevisiae is sensitive to low concentrations of the lipid hydroperoxide - linoleic acid hydroperoxide (LoaOOH) - and its response is unique relative to other peroxide treatments. Part of the yeast response to LoaOOH includes a change in the cellular requirement for nutrients, such as sulfur, nitrogen and various metal ions. The metabolism of sulfur is involved in antioxidant defence, although the role nitrogen during oxidative stress is not well understood. Investigating the response induced by yeast to overcome LoaOOH exposure, with a particular focus on nitrogen metabolism, will lead to greater understanding of how eukaryotes survive lipid hydroperoxide-induced stress, and associated lipid peroxidation, which occurs in the presence of polyunsaturated fatty acids. We used genome-wide microarrays to investigate the changes in gene expression of S. cerevisiae (Dal80Δ) to LoaOOH-induced oxidative stress.
Project description:Oxidative stress is experienced by all aerobic organisms and results in cellular damage. The damage caused during oxidative stress is particular to the oxidant challenge faced, and so too is the induced stress response. The eukaryote Saccharomyces cerevisiae is sensitive to low concentrations of the lipid hydroperoxide - linoleic acid hydroperoxide (LoaOOH) - and its response is unique relative to other peroxide treatments. Part of the yeast response to LoaOOH includes a change in the cellular requirement for nutrients, such as sulfur, nitrogen and various metal ions. The metabolism of sulfur is involved in antioxidant defence, although the role nitrogen during oxidative stress is not well understood. Investigating the response induced by yeast to overcome LoaOOH exposure, with a particular focus on nitrogen metabolism, will lead to greater understanding of how eukaryotes survive lipid hydroperoxide-induced stress, and associated lipid peroxidation, which occurs in the presence of polyunsaturated fatty acids. We used genome-wide microarrays to investigate the changes in gene expression of S. cerevisiae (Dal80M-NM-^T) to LoaOOH-induced oxidative stress. S. cerevisiae (Dal80M-NM-^T) were exposed to an arresting concentration of LoaOOH (75 M-BM-5M) for 1 hr to induce oxidative stress. Yeast treated with an equivalent volume of solvent (methanol) were used as a control. Following treatment conditions, total RNA was extracted from LoaOOH-treated or control yeast and hybridised onto Affymetrix microarrays.
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.
Project description:Cell cycle sensing of oxidative stress in Saccharomyces cerevisiae by oxidation of a specific cysteine residue in the transcription factor Swi6p. Yeast cells begin to bud and enter S phase when growth conditions are favourable during G1 phase. When subjected to oxidative stress, cells arrest at G1 delaying entry into the cell cycle allowing repair of cellular damage. Hence, oxidative stress sensing is coordinated with the regulation of cell cycle. We identified a redox sensing cysteine residue in the cell-cycle regulator of Saccharomyces cerevisiae, Swi6p, at position 404. Mutation of Cys404 to alanine abolished the ability of the cells to arrest at G1 upon treatment by lipid hydroperoxide. By constructing a truncated form of Swi6p, the Cys404 residue was found to be oxidised when cells were subjected to the oxidant. Furthermore, microarray analysis revealed that mutation of Cys404 to alanine led to loss of suppression of G1-cyclins CLN1 and PCL1 when the cells were exposed to lipid hydroperoxide. In conclusion, oxidation of Cys404 serves as a molecular sensor of oxidative stress and inhibits entry into the cell cycle by suppression of G1-cyclin expression. We used a gene expression approach to assess the involvement of Cys404 in oxidative stress by mutating this residue to alanine in order to study whether it contributes to Swi6p, a transcriptional factor, function for redox regulation of the cell cycle. Wild type, swi6-deletant, and swi6 C404A-mutated yeast cells were treated with either linoleic acid hydroperoxide (LoaOOH) or control. Three replicates per group/treatment.
Project description:Raw expression values (CHP data) for transcriptional profiling of the response of Saccharomyces cerevisiae to challenges with lactic acid at pH 3 and pH 5. Keywords: response to lactic acid
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
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