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:Yeast cells can be affected during their growth to several stress conditions. One of the most known and characterised is the osmotic stress and most of the studies about osmotic sterss response in yeast have been focused on salt or sorbitol stress. However, during yeast growth in industrially relevant processes (for instance throughout alcoholic fermentation on the must to produce alcoholic beverages) the osmotic stress is mainly due to the high sugar(in particular glucose) concentration (200-250 g/L). In this study we want to know the transcriptional response of the Saccharomyces cerevisiae when it was grown in a medium with high glucose concentration. For this aim we have grown yeast in YP medium containing 2% of glucose in cultures overnight and after that we diluted this cultures to an OD600 of 0.1 in two differents mediums: YP containing 2% or 20% of glucose.One hour later of inoculation we collect the cells and quikly frozen in liquid nitrogen. We extracted the total mRNA of the cells and after that we did the microarrays, comparing cells were grown in YP2 media against the cells were grown in YP20 media.
Project description:The goal of this study is to analyse how the gene expression in Saccharomyces cerevisiae changes in dependency on the glucose concentration. Therefore, fed batch cultivations were carried out, during which the glucose concentration was maintained stable for several hours. Samples were taken at different times during the cultivations, the RNA was isolated and hybridised on whole genome yeast microarrays. Results from cultivations with the glucose concentrations 50, 70, 100 and 500 mg/L are presented. In addition, one sample from a starvation period (0 mg/L glucose) was analysed. Keywords: Dependency on glucose concentration
Project description:In this study, we used the eukaryotic model Saccharomyces cerevisiae to better understand quinine’s mode of action and the mechanisms underlying the cell response to the drug. We performed a transcriptional profiling of the yeast response to a quinine concentration that exerted a very slight effect over cellular growth.
Project description:Hexokinase 2 (Hxk2) of Saccharomyces cerevisiae is a dual function hexokinase, acting as a glycolytic enzyme and being involved in the transcriptional regulation of glucose-repressible genes. Relief from glucose repression is accompanied by phosphorylation of Hxk2 at serine 15, which has been attributed to the protein kinase Tda1. To explore the role of Tda1 beyond Hxk2 phosphorylation, the proteomic consequences of TDA1 deficiency were investigated by difference gel electrophoresis (2D-DIGE) comparing a wild type and a Δtda1 deletion mutant. To additionally address possible consequences of glucose repression/derepression, both were grown at 2 % and 0.1 % (w/v) glucose. A total of eight protein spots exhibiting a minimum 2-fold enhanced or reduced fluorescence upon TDA1 deficiency was detected and identified by mass spectrometry. Among the spot identities are – besides the expected Hxk2 – two proteoforms of hexokinase 1 (Hxk1). Targeted proteomics analyses in conjunction with 2D-DIGE demonstrated that TDA1 is indispensable for Hxk2 and Hxk1 phosphorylation at serine 15. Thirty-six glucose-concentration-dependent protein spots were identified. A simple method to improve spot quantification, approximating spots as rotationally symmetric solids, is presented along with new data on the quantities of Hxk1 and Hxk2 and their serine 15 phosphorylated forms at high and low glucose growth conditions. The Δtda1 deletion mutant exhibited no altered growth under high or low glucose conditions or on alternative carbon sources. Also, invertase activity, serving as a reporter for glucose derepression, was not significantly altered. Instead, an involvement of Tda1 in oxidative stress response is suggested.
Project description:To understand the organisation of the glucose regulatory system, we analysed 91 deletion mutants of established glucose signalling and metabolic pathway members in Saccharomyces cerevisiae by DNA microarrays. These deletion mutants do not induce pathway-specific transcriptional responses reflecting the tight interconnection between pathways of the glucose regulatory system. Instead, one main transcriptional response is discerned, which varies in direction to mimic either a high or a low glucose response. The study reveals both known and unknown relationships within and between individual pathways and their members. Metabolic components of the glucose regulatory system are most frequently affected at the transcriptional level. A new network approach is applied that exposes the hierarchical organisation of the glucose regulatory system. Tps2 and Tsl1, two enzymes involved in trehalose biosynthesis, are predicted to be the most downstream transcriptional components. This prediction is further validated by epistasis analysis of Tps2 double mutants. Taken together, this suggests that changes in perceived glucose levels ultimately lead to a shift in trehalose biosynthesis.