Project description:Iron-resistant Saccharomyces cerevisiae mutant was obtained by evolutionary engineering selection strategy. The mutant obtained “M8FE” is much more resistant to iron stress than the reference strain which was used to select this mutant. Mutant can resist up to 35mM Iron* stress whereas the reference strain cannot. Whole-genome microarray analysis might be promising to identify the iron resistance mechanisms and stress response upon high levels of iron in the yeast cells. Iron-resistant mutant is also cross resistant to Cobalt, Chromium and Nickel but sensitive to Zinc. * refers to [NH4]2[Fe][SO4]2 and FeCl2.
Project description:High hydrostatic pressure causes physical stress to organisms, and it induces growth inhibition and cellular death. For Saccharomyces cerevisiae, more than 150 MPa at room temperature is lethal conditions. To understand the mechanism of pressure inactivation, we isolated pressure-sensitive mutant strain of S. cerevisiae and analyzed genome-wide mRNA expression profiles using DNA microarray. Mutant strain and parent strain were grown in YPD medium at 30°C for 48 h.
Project description:Second fermentation in a bottle supposes such specific conditions that undergo yeasts to a set of stress situations like high ethanol, low nitrogen, low pH or sub-optimal temperature. Also, yeast have to grow until 1 or 2 generations and ferment all sugar available while they resist increasing CO2 pressure produced along with fermentation. Because of this, yeast for second fermentation must be selected depending on different technological criteria such as resistance to ethanol, pressure, high flocculation capacity, and good autolytic and foaming properties. All of these stress factors appear sequentially or simultaneously, and their superposition could amplify their inhibitory effects over yeast growth. Considering all of the above, it has supposed interesting to characterize the adaptive response of commercial yeast strain EC1118 during second-fermentation experiments under oenological/industrial conditions by transcriptomic profiling. We have pointed ethanol as the most relevant environmental condition in the induction of genes involved in respiratory metabolism, oxidative stress, autophagy, vacuolar and peroxisomal function, after comparison between time-course transcriptomic analysis in alcoholic fermentation and transcriptomic profiling in second fermentation. Other examples of parallelism include overexpression of cellular homeostasis and sugar metabolism genes. Finally, this study brings out the role of low-temperature on yeast physiology during second-fermentation.
Project description:The target of rapamycin (TOR) plays a central role in eukaryotic cell growth control. With prevalent hyper-activation of the mTOR pathway in human cancers, novel strategies to enhance TOR pathway inhibition are highly desirable. We used a yeast-based high-throughput chemical genetic screen to identify small-molecule enhancers of rapamycin (SMERs) and used whole genome expression analysis to identify their mechanisms of action. We incubated Met30 temperature-sensitive yeast strain at either the permissive (room temperature) or non-permissive (35°C) temperature for 1 hour prior to RNA extraction and hybridization on Affymetrix microarrays. Comparison of expression profiles enabled identification of gene-signature characteristic of Met30 inhibition.
Project description:Iron-resistant Saccharomyces cerevisiae mutant was obtained by evolutionary engineering selection strategy. The mutant obtained M-bM-^@M-^\M8FEM-bM-^@M-^] is much more resistant to iron stress than the reference strain which was used to select this mutant. Mutant can resist up to 35mM Iron* stress whereas the reference strain cannot. Whole-genome microarray analysis might be promising to identify the iron resistance mechanisms and stress response upon high levels of iron in the yeast cells. Iron-resistant mutant is also cross resistant to Cobalt, Chromium and Nickel but sensitive to Zinc. * refers to [NH4]2[Fe][SO4]2 and FeCl2. The reference Saccharomyces cerevisiae strain and the iron-resistant mutant were grown in minimal medium to an Optical Density (OD600) of 1.00 which correspond to the logarithmic growth phase of the yeast cells. Cultures were harvested and whole RNA isolation was carried out. The experiment was repeated three times.
Project description:High hydrostatic pressure causes physical stress to organisms, and it induces growth inhibition and cellular death. For Saccharomyces cerevisiae, more than 150 MPa at room temperature is lethal conditions. To understand the mechanism of pressure inactivation, we isolated pressure-sensitive mutant strain of S. cerevisiae and analyzed genome-wide mRNA expression profiles using DNA microarray. Mutant strain and parent strain were grown in YPD medium at 30°C for 48 h. Series contains four hybridization results from independent biological samples respectively in both strains of pressure-sensitive mutant strain and that parent strain.