Project description:This SuperSeries is composed of the following subset Series: GSE37758: Aspergillus niger : Control (fructose) vs. steam-exploded sugarcane induction (SEB) GSE37760: Aspergillus niger : Control (fructose) vs. xylose + arabinose (XA) Refer to individual Series
Project description:Transcriptional profiling of A. niger comparing different strains (WT, M-NM-^TXlnR, M-NM-^TaraR and M-NM-^TaraRM-NM-^TXlnR) treated with 25mM xylose + 25mM arabinose for 2 and 8h. The main objective was to identifiy genes related to primary metabolism and carbohydrate metabolism in general, for instance, cellulases and hemicellulases. The study will compare the differences between WT strain and the strains with the disrupted xylanolytic transcriptional activator gene, XlnR, the arabinolytic transcriptional activator gene, AraR, and the double mutant,after treatment with xylose+arabinose (XA treatment). The experiment was further validated by real-time PCR and enzymatic assays. Two-condition experiment : A. niger mutant strains on XA for 2 and 8 h at 30 oC in batch culture. Firstly, the strains were pre-grown in minimal medium with fructose as carbon source (control), and then transferred to xylose+arabinose (25 mM each) as carbon source.
Project description:Transcriptional profiling of A. niger comparing different strains (WT, ΔXlnR, ΔaraR and ΔaraRΔXlnR) treated with 25mM xylose + 25mM arabinose for 2 and 8h. The main objective was to identifiy genes related to primary metabolism and carbohydrate metabolism in general, for instance, cellulases and hemicellulases. The study will compare the differences between WT strain and the strains with the disrupted xylanolytic transcriptional activator gene, XlnR, the arabinolytic transcriptional activator gene, AraR, and the double mutant,after treatment with xylose+arabinose (XA treatment). The experiment was further validated by real-time PCR and enzymatic assays.
Project description:The full genome sequencing of the filamentous fungi Aspergillus nidulans, Aspergillus niger and Aspergillus oryzae has opened the possibilities for studying the cellular physiology of these fungi on a systemic level. As a tool to explore this, we are presenting an Affymetrix GeneChip developed for transcriptome analysis of any of the three above-mentioned aspergilli. Transcriptome analysis of triplicate batch cultivations of all three aspergilli on glucose-and xylose media has been performed, and used to validate the performance of the micro array. By doing gene comparisons of all three species, and cross-analysing this with the expression data, 23 genes, including the xylose transcriptional activator XlnR, have been identified to be a conserved response across the Aspergillus sp. Promoter analysis of the upregulated genes in all three species suggest the XlnR-binding site to be 5’-GGNTAAA-3’. We are thus presenting a validated tool for transcription analysis of three Aspergillus species and a methodology for comparative transcriptomics. Keywords: Physiological response
Project description:The full genome sequencing of the filamentous fungi Aspergillus nidulans, Aspergillus niger and Aspergillus oryzae has opened the possibilities for studying the cellular physiology of these fungi on a systemic level. As a tool to explore this, we are presenting an Affymetrix GeneChip developed for transcriptome analysis of any of the three above-mentioned aspergilli. Transcriptome analysis of triplicate batch cultivations of all three aspergilli on glucose-and xylose media has been performed, and used to validate the performance of the micro array. By doing gene comparisons of all three species, and cross-analysing this with the expression data, 23 genes, including the xylose transcriptional activator XlnR, have been identified to be a conserved response across the Aspergillus sp. Promoter analysis of the upregulated genes in all three species suggest the XlnR-binding site to be 5’-GGNTAAA-3’. We are thus presenting a validated tool for transcription analysis of three Aspergillus species and a methodology for comparative transcriptomics. Keywords: Physiological response Two conditions (glucose and xylose) and three biological replicates
Project description:Knowledge of the biological and technical variation for fermentor-grown Aspergillus niger cultures is needed to design DNA microarray experiments properly. We cultured A. niger in batch-operated fermentor vessels and induced with D-xylose. Transcript profiles were followed in detail by qPCR for 8 genes. A variance components analysis was performed on these data to determine the origin and magnitude of variation within each process step for this experiment. 6 Fermentor cultures were selected to determine technical and biological variation for all 14554 ORFs present on this array type. Keywords: Validation of microarrays; variation analysis; experimental design
Project description:Knowledge of the biological and technical variation for fermentor-grown Aspergillus niger cultures is needed to design DNA microarray experiments properly. We cultured A. niger in batch-operated fermentor vessels and induced with D-xylose. Transcript profiles were followed in detail by qPCR for 8 genes. A variance components analysis was performed on these data to determine the origin and magnitude of variation within each process step for this experiment. 6 Fermentor cultures were selected to determine technical and biological variation for all 14554 ORFs present on this array type. Keywords: Validation of microarrays; variation analysis; experimental design For 5 weeks, 4 batch-fermentation per week were run in which A. niger was grown on 100 mM sorbitol. At 14 hours after oxygen supply had switched from headspace to sparger-inlet each fermentor was induced with either 0.1 mM D-xylose or 0.1 mM sorbitol. Samples were harvested just before induction and 1 hour after induction. Per week, 3 fermentors were induced with D-xylose and 1 fermentor was induced with sorbitol. Six samples were selected to be put on microarrays based on their biomass density, time distribution, magnitude of xylose-induced genes as measured by qPCR, fermentor vessel number.
Project description:Transcriptomics was performed on batch cultivations of A. niger grown on three monosaccharides and three complex carbohydrates with defined compositions as to allow the detection of cross-induction if present, and for demonstration of how enzyme interaction graphics can be used to visualize the global transcription response. Batch cultivations of A. niger were grown in shake-flasks on one of three monosaccharides (arabinose, glucose, xylose) or one of three complex carbohydrates (arabinan, starch, xylan). Three replicates were performed for each monosaccharide and complex carbohydrate, except for starch, where two replicates were performed.
Project description:To study the induction of the genes encoding known and putative enzymes from the pectinolytic system of A. niger, the transcriptional profiles of 58 selected known or putative pectinolytic genes were monitored by microarray experiments. For this purpose, A. niger was cultivated on the complex substrates, sugar beet pectin and polygalacturonic acid as primary carbon sources. Galacturonic acid, rhamnose and xylose were used to assess the effects on gene expression caused by simple well-defined carbon sources, representing the most abundant sugar residues present in the backbone of pectin. Fructose, as a strong repressor of the expression of genes that are under carbon catabolite regulation, and sorbitol, as a non-inducing sugar-like alcohol, which does not affect the carbon catabolite regulation mechanisms were selected as control substrates. Mycelia of A. niger were pregrown for 18 h on 2% fructose, transferred to medium containing the different pectic and control substrates, and sampled at four time points during 24 h of incubation.