Molecular mechanisms of freeze injuries in commercial baker’s yeast
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE8673 | GEO | 2009/07/31
SECONDARY ACCESSION(S): PRJNA101885
REPOSITORIES: GEO
Similar Datasets
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.
2009-08-09 | E-GEOD-8673 | biostudies-arrayexpress
Project description:Freeze-thaw stress causes various cellular damages, survival and proliferation defects, and metabolic alterations, although how cells cope with it is poorly understood. In this study, model dough fermentations using two different strains of Saccharomyces cerevisiae baker’s yeast were compared after two-week cell preservation in the refrigerator or in the freezer. As a result, one strain specifically exhibited a decreased fermentation rate after exposed to freeze-thaw stress. A DNA microarray analysis of the cells during fermentation revealed that the genes involved in oxidative phosphorylation were upregulated after the freeze-thawing process in the stress-sensitive strain, suggesting a metabolism switching from glycolysis to respiration. In the identical strain, however, most of the genes that encode the components of the proteasome complex were commonly downregulated, and ubiquitinated proteins were highly accumulated by freeze-thaw stress. In the cells with a laboratory-strain background, treatment with a proteasome inhibitor MG132 or deletion of each transcriptional activator gene for the proteasomal genes (RPN4, PDR1, or PDR3) led to a marked decrease in the rate of model dough fermentation using the frozen cells. Based on these data, degradation of freeze-thaw damaged proteins by proteasome may guarantee the high fermentation performance. Furthermore, a heterozygous dominant-negative PDR3 allele (A148T/A229V/H336R/L541P) was found in the diploid genome of the stress-sensitive baker’s yeast strain, which may be associated with the decreased fermentation rate. Removal of such responsible mutations may improve the freeze-thaw stress tolerance and the fermentation performance of baker’s yeast strains, as well as other industrial S. cerevisiae yeast strains.
2017-07-11 | GSE101071 | GEO
Project description:In frozen dough baking technology, baker’s 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.
2009-02-28 | GSE14942 | GEO
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.
2009-08-31 | E-GEOD-15461 | biostudies-arrayexpress
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.
2009-08-31 | GSE15461 | GEO
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
2009-03-07 | E-GEOD-14942 | biostudies-arrayexpress
Project description:Molecular mechanisms of freeze injuries in commercial baker’s yeast
| PRJNA101885 | ENA
Project description:Gene expression profiles of baker’s yeast during initial dough-fermentation were investigated using liquid fermentation media to obtain insights at the molecular level into rapid adaptation mechanisms of baker’s 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 baker’s yeast during dough-fermentation, and will thus help clarify genomic responses to various stresses during commercial fermentation processes. Keywords: fermentation
2006-02-24 | GSE3043 | GEO
Project description:Environmental conditions are quite effective during propagation and industrial application of Baker’s yeast (Saccharomyces cerevisiae). The change of temperature is one of the most important conditions which affects the dough-leaving capacity of yeast cells. Accordingly, heat changes play an essential role in the commercial and economic impact of the yeast. Recent technologies in genomics have been used for analysis of global gene expression profiles such as microarray and RNA sequencing to solve the problems related with industrial application of yeast. Hereby, the aim of this study is to explore the effects of heat stresses on global gene expression profiles and to identify the candidate genes for the heat stress response in commercial baker’s yeast by using microarray technology and comparative statistical data analyses. Data from all hybridizations and array normalization were analyzed using the GeneSpringGX 12.1 (Agilent) and the R 2.15.2 program language. In the analysis of this dataset, all required statistical methods are performed comparatively in each step and the best performed ones are used in further computations. Hence, as the first step of the analyses, different background normalization algorithms such as MAS5.0, RMA, MBEI and GC-RMA were applied and the algorithm which gives the most accurate findings was chosen for the normalization procedure. As a result, expression values, computed from CEL files, were processed by Robust Multiarray Analysis (RMA) which is the selected procedure for the normalization of the systematic differences between samples. In order to determine differentially expressed genes under heat stress treatments, two different methods, namely, the fold-change and the hypothesis testing approaches are executed. In the fold-change method, various cut-off values are implemented while different multiple testing procedures are performed for the hypothesis testing. Under the heat shock and temperature-shift stress conditions, up/down regulated differentially expressed probes were functionally categorized into the different groups via the cluster analyses. Transcriptome changes under the heat shock and temperature-shift stress treatments show that the number of differentially up-regulated genes among the heat shock proteins (HSPs) and transcription factors (TFs) changed significantly. Consequently, the identification of thousands of genes related with heat stress treatments via microarray technology and comparative statistical analysis resulted in the creation of big picture which provides the understanding of the importance for the baker’s yeast industrial applications.
2017-01-30 | E-MTAB-3459 | biostudies-arrayexpress
Project description:RNA-Seq is ubiquitous, but depending on the study, sub-optimal sample handling may be required, resulting in repeated freeze-thaw cycles. However, little is known about how each cycle impacts downstream analyses, due to a lack of study and known limitations in common RNA quality metrics, e.g., RIN, at quantifying RNA degradation following repeated freeze-thaws. Here we quantify the impact of repeated freeze-thaw on the reliability of downstream RNA-Seq analysis. To do so, we developed a method to estimate the relative noise between technical replicates independently of RIN. Using this approach we inferred the effect of both RIN and the number of freeze-thaw cycles on sample noise. We find that RIN is unable to fully account for the change in sample noise due to freeze-thaw cycles. Additionally, freeze-thaw is detrimental to sample quality and differential expression (DE) reproducibility, approaching zero after three cycles for poly(A)-enriched samples, wherein the inherent 3’ bias in read coverage is more exacerbated by freeze-thaw cycles, while ribosome-depleted samples are less affected by freeze-thaws. The use of poly(A)-enrichment for RNA sequencing is pervasive in library preparation of frozen tissue, and thus, it is important during experimental design and data analysis to consider the impact of repeated freeze-thaw cycles on reproducibility.
2020-05-09 | GSE150097 | GEO