Project description:We analyzed genome-wide transcriptional profiles of Saccharomyces cerevisiae BY4742 strain in response to BPA, focusing on two exposure scenarios: (i) low-observed-effect concentration (<10% inhibition) to examine chronic effect of BPA on yeast population, and (ii) high-inhibitory concentration (>70% inhibition) to study acute effect. Initially, yeast cells were exposed to various concentrations of BPA. 50 mg/L and 300 mg/L BPA were determined as low-observed-effect concentration and the high-inhibitory concentration, respectively. Transcriptional profiles indicated that 81 genes were repressed and 104 genes were induced in response to 50 mg/L BPA. On the other hand, in 300 mg/L BPA exposure, 378 genes were down-regulated, while 606 genes were significantly up-regulated. Our data showed that there were similar processes affected by both concentrations such as mitochondria, nucleobase-containing small molecule metabolic process, transcription from RNA polymerase II promoter, and mitotic cell cycle and associated processes. However, different modes of actions of the BPA were found between two concentrations. 300 mg/L BPA exposure showed severe effects on the processes by repressing or inducing several genes or total mechanisms with high level of expression changes, while 50 mg/L BPA exposure changed the expression of some important genes with low level of expression changes in the processes. These results suggest that yeast cells respond via different ways to the different concentrations of BPA at transcriptomic level.
Project description:Yeast replicative aging is a process resembling replicative aging in mammalian cells. During aging, wild type haploid yeast cells enlarge, become sterile, and undergo nucleolar enlargement and fragmentation; we sought gene expression changes during the time of these phenotypic changes. Gene expression studied via microarrays and qPCR has shown reproducible, statistically significant changes in mRNA of genes at 12 and 18-20 generations. Our findings support previously described changes towards aerobic metabolism, decreased ribosome gene expression, and a partial Environmental Stress Response. Our novel findings include a pseudo-stationary phase, down-regulation of methylation-related metabolism, increased Nucleotide Excision Repair related mRNA, and a strong up-regulation of many of the regulatory subunits of protein phosphatase I (Glc7). These findings are correlated with aging changes in higher organisms as well as with the known involvement of protein phosphorylation states during yeast aging. J Gerontol, Jan, 2008, vol 63A, no. 1. Keywords: aging time course
Project description:Effect of FLO8 or MSS11 deletion and -overexpression on yeast transcript profiles compared to wild type in laboratory yeast strains Σ1278b and S288c.
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:Effect of FLO8 or MSS11 deletion and -overexpression on yeast transcript profiles compared to wild type in laboratory yeast strains ?1278b and S288c. We used two laboratory yeast strains that behave different with regard to adhesion phenotypes. By comparing yeast deleted in either FLO8 or MSS11 to wild type, or yeast overexpressing these genes, in both genetic backgrounds, we investigate the role of Flo8p and Mss11p on yeast transcription. By using similar growth conditions to what we use for adhesion phenotype determination we aim to correlate transcription profile changes to yeast behaviour (phenotypes).
Project description:In this study, we focused on air-drying stress and analyzed the changes in gene expression of commercial baker’s yeast during the air-drying process. Changes in gene expression profiles of commercial baker’s yeast during an air-drying process at 37oC that simulated dried yeast production were analyzed using DNA microarrays. Keywords: Stress response