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.
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: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: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: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:Here we used mass spectrometry-based proteomics technology to explore SEPs with potential cellular stress function in Saccharomyces cerevisiae. Microproteins with unique peptides were identified under six culture conditions: normal, oxidation, starvation, UV radiation, heat shock, and heat shock with starvation.
Project description:Saccharomyces cerevisiae cells have evolved remarkably sophisticated and flexible transcriptional regulatory networks (TRNs) that allow them to survive and thrive in stress conditions, such as high temperature, osmotic and oxidative conditions, etc. Furthermore, transcription factor plays a central role in transcriptional regulatory networks of stress response. To achieve a thorough understanding of master transcription factors and transcriptional regulatory networks in specific response to prolonged thermal stress, we sequenced mRNA from the cultures of the wild type strain ScY01a as well as four key transcription factor deletion strains including ScY01a (ric1∆), ScY01a (srb2∆), ScY01a (sin3∆) and ScY01a (mig1∆) grown at 40ºC in biological duplicates. Differences in gene expression comparing the transcription factor deletion strains with the wild type strain by RNA deep sequencing revealed a hierarchical transcriptional regulatory network required for long-term thermal stress tolerance of S. cerevisiae, which is centered on these four transcription factors.
Project description:Industrial bioethanol production may involve a low pH environment,improving the tolerance of S. cerevisiae to a low pH environment caused by inorganic acids may be of industrial importance to control bacterial contamination, increase ethanol yield and reduce production cost. Through analysis the transcriptomic data of Saccharomyces cerevisiae with different ploidy under low pH stress, we hope to find the tolerance mechanism of Saccharomyces cerevisiae to low pH.