Project description:The model yeast species Saccharomyces cerevisiae is used in many fundamental and applied research applications, including biosensors and production of many compounds. However, given the enormous work invested in the studies of yeast transcription response to various conditions, there are still substances not explored in this regard. In this work, we explore the transcriptional response of S. cerevisiae to a wide range of concentrations of the D-enantiomer of lactic acid and compare it to the response to L-lactic acid. Of these conditions, we only recorded a transcriptional response to the relatively high concentrations of DLA of 5 and 45 mM, as well as to 45 mM LLA. Our data did not reveal any natural yeast promoters that quantitatively sense D-lactic acid but provide the first description of the transcriptome-wide response to DLA, as well as enrich our understanding of the LLA response.
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:Differential gene expression analysis of five different strains of Crabtree-negative Saccharomyces cerevisiae that lack pyruvate decarboxylase activity. The three different acids studied were lactic, malic, and 3-hydroxypropionic acid.
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:D-lactic acid is a three-carbon organic acid with a chiral structure and can improve the thermostability of polylactic acid. Microorganisms such as the methylotrophic yeast Pichia pastoris, which lack the natural ability to produce or accumulate high amounts of D-lactic acid, have been engineered to produce it in high titers. However, tolerance to D-lactic acid remains a challenge. In this study, we demonstrate that cell flocculation improves tolerance to D-lactic acid and leads to increased D-lactic acid production in Pichia pastoris. By incorporating a flocculation gene from Saccharomyces cerevisiae (ScFLO1) into P. pastoris KM71, we created a strain (KM71-ScFlo1) that demonstrated up to a 1.6-fold improvement in specific growth rate at high D-lactic acid concentrations. Furthermore, integrating a D-lactate dehydrogenase gene from Leuconostoc pseudomesenteroides (LpDLDH) into KM71-ScFlo1 resulted in an engineered strain (KM71-ScFlo1-LpDLDH) that can produce D-lactic acid at a titer of 5.12 0.35 g/L in 48 hours , a 2.6-fold improvement over the control strain lacking ScFLO1 expression. Transcriptomics analysis of this strain provided insights into the mechanism of increased tolerance to D-lactic acid including the upregulations of genes involved in lactate transport and iron metabolism. Overall, our work represents an advancement in the efficient microbial production of D-lactic acid by manipulating yeast flocculation.
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. Experiment Overall Design: The laboratory reference strain CEN.PK 113-7D (MATa) was grown at 30 °C in 1.5-L chemostat fermentors (Applikon, Schiedam, The Netherlands) with a working volume of 1-L using an electronic level sensor to maintain a constant volume. All cultures, including the reference, were fed with minimal medium as described by Verduyn et al. (1992) with 25 g L-1 glucose as the limiting nutrient and 0.15 ml L-1 silicone antifoam (BDH, Poole, England) to prevent excessive foaming. The dilution rate was set to 0.10 h-1 and the pH was controlled at 5.0 with the automatic addition (ADI 1031 bio controller, Applikon) of 2 M KOH. The stirrer speed was set at 800 RPM and anaerobicity was maintained by sparging the fermentor with N2 gas at 500 ml min-1. To prevent diffusion of oxygen, the fermentor was equipped with Norprene tubing and Viton O-rings and the medium vessel was also flushed with N2 gas. A comparable degree of weak acid uncoupling was ensured by decreasing the biomass yield to approximately 50% of the reference condition (no organic acids added) with the addition of the appropriate concentration of lactic acid to the reservoir media. Experiment Overall Design: Sampling of chemostat cultures, probe preparation and hybridization to Affymetrix GeneChip microarrays was performed as described previously (Piper et al., 2002), but with the following modifications. Double-stranded cDNA synthesis was carried out using 15 μg of total RNA and the components of the One Cycle cDNA Synthesis Kit (Affymetrix). The double-stranded cDNA was purified (Genechip Sample Cleanup Module, Qiagen) before in vitro transcription and labeling (GeneChip IVT Labeling Kit, Affymetrix). Finally, labeled cRNA was purified (GeneChip Sample Cleanup Module) prior to fragmentation and hybridization of 15 μg of biotinylated cRNA. Experiment Overall Design: Data acquisition was performed using the Affymetrix scanner 3000, quantification of array images and data filtering were performed with the Affymetrix software packages Microarray Suite v5.0, MicroDB v3.0 and Data Mining Tool v3.0.
Project description:The initial translational response of the yeast Saccharomyces cerevisiae in response to acetic acid-induced apoptosis was investigated by microarray profiling of mRNAs contained in polysomal fractions obtained upon 0 (used as control), 15 and 30 minutes of acetic acid treatment. The mRNA fraction thus investigated corresponds to the mRNAs capable of overcoming the inhibition of cap-mediated translation initiation.
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: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.