Project description:In the present work, we aimed at investigating how the respective composition (especially the peptide content) of two different yeast extracts influenced Streptococcus metabolism during growth. To reach that goal, we used one strain of S. thermophilus (N4L) and two yeast extract-based growth media leading to similar fermentation kinetics and yields that differed by their peptide content. Three replicate cultures were performed for each yeast extract-based growth medium, under pH control. Samples were collected after 3, 4 and 5 h of growth, cells were harvested
Project description:High glucose concentrations were desirable for ethanol fermentation of Zymomonas mobilis, but it can lead to decrease in ethanol production and productivity. Sorbitol as a compatible solute can be absorbed or synthesized to counteract the detrimental osmotic stress caused from external high glucose concentrations by Z. mobilis. Currently, molecular mechanisms of tolerance to high glucose concentrations and sorbitol promoting ethanol fermentation are still unclear for Z. mobilis. To better understand mechanisms with which high concentrations of glucose and sorbitol affect physiology and metabolism of Z. mobilis ATCC31821 (ZM4), the global transcriptional responses of ZM4 to the challenge of high glucose concentration and sorbitol were profiled using whole genome microarray analysis. Swings J, Deley J. Bacterial Rev. 1977, 41(1): 1-46. Loos H, Kramer R, Sahm H and Sprenger GA. J Bacteriol. 1994, 176(24):7688–7693.
Project description:We used genome-wide expression analyses to study the response of Saccharomyces cerevisiae to stress throughout a 15-day wine fermentation. Forty percent of the yeast genome significantly changed expression levels to mediate long-term adaptation to an environment in which ethanol is both a stressor and a carbon source. Within this set, we identify a group of 223 genes, designated as the Fermentation Stress Response (FSR), that are dramatically and permanently induced; FSR genes exhibited changes ranging from four-to eighty-fold. The FSR is novel; 62% of the genes involved have not been implicated in global stress responses and 28% of the genes have no functional annotation. Genes involved in respiratory metabolism and gluconeogenesis were expressed during fermentation despite the presence of high concentrations of glucose. Ethanol, rather than nutrient depletion, was responsible for entry of yeast cells into stationary phase. Ethanol seems to regulate yeast metabolism through hitherto undiscovered regulatory networks during wine fermentation. Keywords: time course, stress response, fermentation
Project description:Human aortic endothelial cells were grown in culture until confluent. In three experiments using cells derived from three separate donors confluent cultures were incubated for 6 h with contol medium, or medium containing either extracts of oligomeric procyanidins from cranberry juice or red wine, or a procyanidin-rich grape seed extract. At the end of the 6 h treatment period conditioned media samples were retained for immunoassay of secreted peptides and proteins, and RNA was extracted for microarray analysis. Experiment Overall Design: Each experiment used cells from one donor. Treatment conditions were: control medium, cranberry extract (CRE), grape seed extract (GSE), and red wine extract (RWE).
Project description:This experiment was used to determine the effect of a botanical insecticide upon gene expression profiles in Drosophila melanogaster. Adult female Drosophila (oregon-R strain) were treated with an ethylacetate extract of Piper nigrum (Piperaceae) seeds formulated in 99% ethanol. Treatment was topical, using a Potter's tower to administer a total of 2 mL of a 0.9mg/mL concentration. Control treatment was identical except flies were treated with 99% ethanol as a solvent control. Gene expression was studied four hours post-treatment. Keywords: insecticide response, stress-response
Project description:We have previously shown that fed-batch processes with the longest uncoupling phase (ethanol adapted) were characterized by induction of storage carbohydrates, a metabolic event typical of yeast cells experiencing nutrient limitation, at the onset of this phase, whereas this metabolic event was not seen in processes with a short uncoupling phase (ethanol non adapted culture). Taken together, our results suggested that reproducible high bioethanol performance in aerated fed-batch process may be linked to the ability of yeast cells to impede ethanol toxicity by triggering a metabolic remodelling reminiscent to that of cells entering a quiescent G0/G1 state. The aim of this study was to search for genes implicated in the induction an ethanol adapted culture vs ethanol non-adapted culture. We measure the changes in the gene expression of Ethanol adapted culture (Test : fermentation I in ref 17005001[PMID]) and Ethanol non-adapted (reference : Fermentation II in ref 17005001[PMID]) at the same ethanol concentration of 60 g/l and the same growth rate of the cells (0,14 h-1 :Test) and (0,13 h-1 : reference) to reduce the risk of observing secondary effects due to growth and ethanol stress. For each sample, total RNAs from one yeast culture (no biological replicate) were extracted four times (technical replicates -extract). For labelling, we employed a dye-switch (dCTP-Cy3 and dCTP-Cy5) repeated 2 times and hybridized cDNA on four independent microarrays, given rise to eight data value per gene (each gene is duplicate on the slide).
Project description:High concenHigh concentration acetic acid in the fermentation medium represses cell growth, metabolism and fermentation efficiency of Saccharomyces cerevisiae, which is widely used for cellulosic ethanol production. Our previous study proved that supplementation of zinc sulfate in the fermentation medium improved cell growth and ethanol fermentation performance of S. cerevisiae under acetic acid stress condition. However, the molecular mechanisms is still unclear. To explore the underlying mechanism of zinc sulfate protection against acetic acid stress, transcriptomic and proteomic analysis were performed. The changed genes and proteins are related to carbon metabolism, amino acid biosynthesis, energy metabolism, vitamin biosynthesis and stress responses. In a total, 28 genes showed same expression in transcriptomic and proteomic data, indicating that zinc sulfate affects gene expression at posttranscriptional and posttranslational levels.tration acetic acid in the fermentation medium represses cell growth, metabolism and fermentation efficiency of Saccharomyces cerevisiae, which is widely used for cellulosic ethanol production. Our previous study proved that supplementation of zinc sulfate in the fermentation medium improved cell growth and ethanol fermentation performance of S. cerevisiae under acetic acid stress condition. However, the molecular mechanisms is still unclear. To explore the underlying mechanism of zinc sulfate protection against acetic acid stress, transcriptomic and proteomic analysis were performed. The changed genes and proteins are related to carbon metabolism, amino acid biosynthesis, energy metabolism, vitamin biosynthesis and stress responses. In a total, 28 genes showed same expression in transcriptomic and proteomic data, indicating that zinc sulfate affects gene expression at posttranscriptional and posttranslational levels.
Project description:Ethanol-stressed conditions were applied to ε-polylysine fermentation to study the changes in protein levels of Streptomyces albicans under ethanol-stimulated conditions
Project description:The yeast Saccharomyces cerevisiae is well known for its high ethanol production performances. An original fermentation process that allows the yeast S. cerevisiae to produce in less than 45 h more than 150 g/l ethanol (i.e. 18.9°GL) was set up in our laboratory [1]. Under this condition, the yeast cells induce a dynamic process to adapt to increased ethanol concentration by a mechanism that is likely different to the stress response triggered by sudden ethanol addition to exponentially growing cells [2]. Kinetic analysis of the growth curve identified two main phases: a growth phase that ended up at 90 g/l ethanol and then an uncoupling phase during which non-growing cells kept producing ethanol. This latter phase is also characterized with an increased loss of viability. In order to investigate on a genome scale the expression changes occurring during this process, gene expression was quantified using DNA chips technology at six different time-points during fed-batch fermentation. [1] Alfenore et al, Appl. Microbiol. Biotechnol. 60 : 67-72, 2002. [2] Alexandre H. et al., FEBS Lett. 498(1) : 98-103, 2001. We measure the changes in the gene expression of ethanol stressed culture at five different time-points during fed-batch fermentation compared to a common reference consisting of exponentially growing yeast cells ( sample number 1 : growing cells ; low ethanol concentration of 17 g/l ; specific growth rate of 0.3 h-1) . The sets corresponded to sample number 2 : growing cells/ethanol concentration of 60 g/l ; sample number 3 : before growth arrest/ethanol concentration of 90 g/l ; sample number 4 : growth arrest/ethanol concentration of 95 g/l ; sample number 5 : 1 hour after growth arrest/ethanol concentration of 100 g/l and sample number 6 : uncoupling phase/ethanol concentration of 125 g/l. For each sample, total RNAs from one yeast culture (no biological replicate) were extracted three times (technical replicates -extract). For labelling, we labelled the common reference with dCTP-Cy5 and labelled the sample with dCTP-Cy3 and hybridized cDNA on three independent microarrays, given rise to six data value per gene (each gene is duplicate in the slide).