Transcription profiling of S. cerevisiae samples exposed to sugar stress during fermentation
Ontology highlight
ABSTRACT: Functional genomic analysis using different types of baker's yeast. Experiment Overall Design: Fermentation at different concentrations of sucrose. Experiment Overall Design: PerChip normalization using only positive (exclude pombe) genes and PerGene normalization were applied using GeneSpring (v7.0).
Project description:In frozen dough baking technology, bakerâs yeast Saccharomyces cerevisiae encounter freeze-thaw injury. After thawing, dramatically decrease in cell viability and fermentation activity is caused by freeze-thaw injury. The freezing period is critical factor in freeze-thaw injury, thus we focused and investigated time-dependent gene expression profiles in recovery process from freeze injury. First, changes in gene expression profiles in S. cerevisiae in recovery process from freeze-thaw injury were analyzed using a DNA microarray. The results showed the genes which were involved in homeostasis of metal ions were time-dependent up-regulated 2-fold or more in a series. Then we examined whether these genes were related to tolerance in freeze-thaw injury by using deletion strain. The results showed that deletion of MAC1, CTR1, and PCA1 genes which involved in copper ion transport exhibited freeze-thaw sensitivity in compared with wild type. These genes are involved in copper ion uptake to a cell under a copper deficiency condition or in copper ion homeostasis, suggesting that it may be related between freeze-thaw injury and copper ion transport. To determine the effect of supplementation of copper ion on cells after freeze-thaw treatment, cell viability, intracellular superoxide dismutase (SOD) activity, and intracellular levels of reactive oxygen species (ROS) were examined by various copper ion condition medium. The results showed that intracellular SOD activity was increased and intracellular levels of ROS were decreased by supplementation of copper ion, but there was no significant difference in cell viability. These results of the present study may suggest that copper ion concentration in yeast cell after freeze-thaw treatment is important to recovery from freeze-thaw injury due to redox control of intracellular levels of ROS, but copper ion did not directly affect cell viability. Experiment Overall Design: Total RNA was extracted from the stress-treated yeast cells by using a hot phenol method. Poly(A)+ RNA was enriched from total RNA by using an Oligotex dT30 (Super) mRNA purification kit (Takara Bio, Ohtsu, Japan). cDNA synthesis, cRNA synthesis, and labeling were performed according to the Affymetrix userâs manual (Affymetrix, Santa Clara, USA). Biotinyated cRNA was fragmented and then used as a probe.Affimetrix Yeast Genome 2.0 arrays (Affymetrix) were used as DNA microarrays. All experiments were done in duplicate independently
Project description:Saccharomyces cerevisiae is exposed to freeze-thaw stress in commercial processes including frozen dough baking. The cell viability and fermentation activity after freeze-thaw were dramatically decreased due to freeze-thaw injury. Because freeze-thaw injury involves complex phenomena, the mechanisms of it are not fully understood. We attempted to analyze the mechanisms of freeze-thaw injury by indirect gene expression analysis during post-thaw incubation after freeze-thaw treatment using DNA microarray profiling. The results showed that a high frequency of the genes involved in the homeostasis of metal ions were up-regulated depending on the freezing period. The phenotype of the deletion mutants of the up-regulated genes extracted by indirect gene expression analysis was assessed. The deletion strains of the MAC1 and CTR1 genes involved in copper ion homeostasis exhibited freeze-thaw sensitivity, suggesting that copper ion homeostasis is required for freeze-thaw tolerance. Supplementation with copper ions during post-thaw incubation increased intracellular superoxide dismutase activity. Inverse correlated with intracellular superoxide dismutase activity, intracellular levels of reactive oxygen species were decreased. Moreover, cell viability increased by supplementation with copper ions under specific assessment conditions. This study suggested that insufficiency of copper ion homeostasis may be one of the causes of freeze-thaw injury. Total RNA was extracted from the stress-treated yeast cells by using a hot phenol method. Poly(A)+ RNA was enriched from total RNA by using an Oligotex dT30 (Super) mRNA purification kit (Takara Bio, Ohtsu, Japan). cDNA synthesis, cRNA synthesis, and labeling were performed according to the Affymetrix user’s manual (Affymetrix, Santa Clara, USA). Biotinyated cRNA was fragmented and then used as a probe.Affimetrix Yeast Genome 2.0 arrays (Affymetrix) were used as DNA microarrays. All experiments were done in triplicate independently.
Project description:Gene expression profiles of bakerâs yeast during initial dough-fermentation were investigated using liquid fermentation media to obtain insights at the molecular level into rapid adaptation mechanisms of bakerâs yeast. Results showed that onset of fermentation caused drastic changes in gene expression profiles within 15 min. Genes involved in the tricarboxylic acid (TCA) cycle were down-regulated and genes involved in glycolysis were up-regulated, indicating a metabolic shift from respiration to fermentation. Genes involved in ethanol production (PDC genes and ADH1), in glycerol synthesis (GPD1 and HOR2), and in low-affinity hexose transporters (HXT1 and HXT3) were up-regulated at the beginning of model dough-fermentation. Among genes up-regulated at 15 min, several genes classified as transcription were down-regulated within 30 min. These down-regulated genes are involved in messenger RNA splicing and ribosomal protein biogenesis, in zinc finger transcription factor proteins, and in transcriptional regulator (SRB8, MIG1). In contrast, genes involved in amino acid metabolism and in vitamin metabolism, such as arginine biosynthesis, riboflavin biosynthesis, and thiamin biosynthesis, were subsequently up-regulated after 30 min. Interestingly, the genes involved in the unfolded protein response (UPR) pathway were also subsequently up-regulated. Our study presents the first overall description of the transcriptional response of bakerâs yeast during dough-fermentation, and will thus help clarify genomic responses to various stresses during commercial fermentation processes. Experiment Overall Design: Saccharomyces cerevisiae T128 was used as a model of typical commercial bakerâs yeast used in Japan. After 18 h cultivation, cells in stationary phase were collected by centrifugation (2,700 ï g for 5 min). Some of the cell pellets were suspended in 900 ml of sterilized water. Cells for no-fermentation control were harvested after the fed-butch cultivation and stored until RNA extraction. Cell pellets (11,700 OD units) were suspended in 390 ml of lequid fermentation (LF) medium in a 500-ml flask and then fermented for 300 min. To investigate gene expression profiles during initial stages of dough-fermentation, cell samples for DNA microarray analysis were obtained from each culture medium at 15 min, 30 min, and 60 min. Cells in stationary phase were then collected by centrifugation (2,700ï g for 5 min), and stored until RNA extraction.
Project description:Frozen dough baking is useful method in the modern bread-making industry. However, the fermentation activity of bakerâs yeast dramatically decreased after thawing due to freeze injuries, because bakerâs yeast cells contained in dough experience freeze injuries during freeze-thaw processes. Here, we performed genome-wide expression analysis to determine genetic response in bakerâs yeasts under freeze-thaw condition using a DNA microarray analysis. Functional and clustering analyses in gene expression reveal that genes could be characterized by the term of freeze-thaw stress. Under short-term freeze stress (freeze treatment for 3 day), genes involved in ribosomal protein were up-regulated. Under long-term freeze stress (freeze treatment for longer than 7 day), genes involved in energy synthesis were up-regulated. In each phase, genes involved in protein damage, several stresses and trehalose and glycogen metabolism were also up-regulated. Through these freeze stress, yeast cells may improve reduced efficiency of translation and enhanced cell protection mechanism to survive under freeze stress condition. These regulations of these genes would be controlled by the cAMP-protein kinase A pathway. Experiment Overall Design: All experiments were done in duplicate from two independent samples.
Project description:Investigation of whole genome gene expression level in Pseudozyma antarctica T-34, compared to Ustilago maydis UM521. To clarify the transcriptomic characteristics of Pseudozyma antarctica under the conditions of high MEL production, a DNA microarray of both the strains, Pseudozyma antarctica T-34 and Ustilago maydis UM521 was prepared and analyzed the transcriptomes. A DNA chip study using mRNA from the cultures of Pseudozyma antarctica T-34 and Ustilago maydis UM521 demonstrated the gene expression level of each strain.
Project description:The vanillin tolerance Saccharomyces cerevisiae was screened and compared intracellular ergosterol levels with several laboratory yeast strains, to study potential relationship between ergosterol contents and vanillin tolerance. S. cerevisiae NBRC1950 was selected as a vanillin tolerant strain. Its ergosterol contents were higher than those of laboratory strains. The results of DNA microarray and quantitative RT-PCR analysis showed that 5 genes involved in ergosterol biosynthesis (ERG28, HMG1, MCR1, ERG5 and ERG7) were up-regulated in NBRC 1950 compared with strain X2180, suggested that high expressions of genes involved in ergosterol biosynthesis may cause for the high ergosterol content in strain NBRC 1950. S. cerevisiae HX strain, which was a high ergosterol content strain derived from X2180, became more tolerant to vanillin compared with the parental strain. It is suggested that high ergosterol contents may be in part responsible for vanillin tolerance. These findings provide a biotechnological basis for the molecular engineering of S. cerevisiae with increased tolerance to vanillin. Experiment Overall Design: Total RNA was extracted from cells in YPD media with shakin by using a hot phenol method. Poly(A)+ RNA was enriched from total RNA by using an Oligotex dT30 (Super) mRNA purification kit (Takara Bio, Ohtsu, Japan). cDNA synthesis, cRNA synthesis, and labeling were performed according to the Affymetrix userâs manual (Affymetrix, Santa Clara, USA). Biotinyated cRNA was fragmented and then used as a probe.Affimetrix Yeast Genome 2.0 arrays (Affymetrix) were used as DNA microarrays. All experiments were done in duplicate independently. Statistical analysis after data acquisition and normalization of expression data were performed using GeneSpring ver.7.3.1 (Agilent Technologies, Palo Alto, CA, USA) based on the gene expression data from two independent experiments. After data transformation to GeneSpring, per-chip normalization to the 50th percentile was performed, and per-gene normalization to the specific samples (X2180 samples) was applied to the per-chip normalized data. Quality control was performed based on experimental confidence levels (each condition in which all samples were present or marginal) and on statistical confidence levels (condition in which P-value of T-test comparisons between X2180 and NBRC 1950 was less than 0.05).
Project description:Transition from proliferation to quiescence brings about extensive changes in cellular behavior and structure. However, genes critical for establishing and/or for maintaining quiescence are largely unknown. The fission yeast S. pombe is found as an excellent model for studying this problem, because it becomes quiescent under nitrogen starvation. Here we characterize 610 temperature-sensitive (ts) mutants, and identify 33 genes required for entry into and the maintenance of quiescence. These genes cover a broad range of cellular functions in the cytoplasm, membrane and the nucleus, encoding proteins for stress-responsive and cell cycle kinase signaling pathway, actin-bound and osmo-controlling endosome formation, RNA transcription, splicing and ribosome biogenesis, chromatin silencing, biosynthesis of lipid and ATP, cell wall and membrane morphogenesis, protein trafficking and vesicle fusion. We specifically highlight Fcp1, CTD phosphatase of RNA polymerase II, which differentially affects transcription of genes involved in quiescence and proliferation. We propose that the transcriptional role of Fcp1 is central to differentiate quiescence from proliferation. Experiment Overall Design: Gene expression profile under nitrogen rich or starved condition at 26ºC or 37ºC in WT (L972) or fcp1-452 ts mutant strain of fission yeast.
Project description:Fission yeast Schizosaccharomyces pombe is a model for studying cellular quiescence. Shifting to medium without a nitrogen-source induces proliferative cells to enter long-term G0 quiescence. Klf1 is a Kruppel-like transcription factor with a 7-amino acid-spaced C2H2-type zinc finger motif. The deletion mutant M-bM-^HM-^Fklf1 normally divides in vegetative medium, but proliferation is not restored after long-term G0 quiescence. Cell biologic, transcriptomic, and metabolomic analyses revealed a unique phenotype of the M-bM-^HM-^Fklf1 mutant in quiescence. Mutant cells had diminished transcripts related to signaling molecules for switching to differentiation. In contrast, proliferative metabolites for cell-wall assembly and antioxidants significantly increased. Further, the size of the M-bM-^HM-^Fklf1 cells is markedly increased during quiescence due to the aberrant accumulation of calcofluor-positive chitin-like materials beneath the cell wall. After 4 weeks quiescence, the ability for reversible proliferation is lost, but energy metabolism is maintained. Klf1 thus plays a role in G0 phase longevity through enhancing the differentiation signal and suppressing metabolism for growth. If Klf1 is lost, S. pombe fails to maintain a constant cell size during quiescence. Gene expression profile of fission yeast wild type cells and klf1-gene disruptant cells in proliferating state and in quiescent state. Type of experiment: Comparing between wild type cells and klf1-gene disruptant cells in proliferating condition and in quiescent condition. Experimental factor: Exponentially proliferating state in synthetic medium, EMM2, and quiescent G0 state in nitrogen-depleted synthetic medium, EMM2-N. Quality control steps taken: All experiments were repeated twice in each condition.
Project description:In this study, using DNA microarray analysis, we compared the comprehensive expression profiles of two yeast trains, i.e, the previously obtained ethanol-adapted yeast strain and the parental strain as control (FY834), under the ethanol stress condition (YPD medium contained 10% ethanol). As a result, we identified certain genes and functional categories of the genes that are possible involved in growth under the ethanol stress condition. The ethanol adapted and FY834 yeasts were cultivated in YPD medium containing 10% ethanol. For the control, FY834 strain was cultivated in YPD medium. Cells were harvested in the logarithmic growth phase and then immediately frozen in liquid nitrogen. Total RNA was extracted by the hot phenol method and purified into mRNA using an Oligo dT30<Super> mRNA purification kit. Cy3-labelled cDNA targets were prepared from 1.5 µg of mRNA samples of yeasts grown in the ethanol stress condition. Cy5-labelled cDNA targets were prepared from 1.5 µg of mRNA samples of yeast grown in YPD. Cy3-and Cy5-labelled cDNA targets were mixed and then hybridized with probes on the DNA microarray, Yeast gene chip ver.2. (DNA Chip Research Inc.,Japan). The preparation of fluorescent-dye-labeled cDNA targets, hybridization, and washing were carried out as described in instruction manuals supplied by the manufacturer of the DNA microarray.
Project description:To investigate the major components of the response to the methylation inhibitor 3-deazadenosine U2OS cells were plated in 20 cm dishes and grown until confluence. Cells were then treated with 100 microM deazaadenosine or vehicle (PBS) for 24 hours. Three replicate dishes for each treatment were analysed.