Project description:Guar gum consists mainly of galactomannan, and constitutes the endosperm of guar seeds that acts as a reserve polysaccharide for germination. Due to its molecular structure and physical properties, this biopolymer has been considered as one of the most important and widely used gums in industry. However, for many of these applications this (hemi-)cellulosic structure needs to be modified or (partially) depolymerized in order to customize and improve its physicochemical properties. In this study, transcriptome was employed to decipher the complete enzymatic arsenal for guar gum depolymerization by Aspergillus niger.
Project description:Non-alcoholic fatty liver disease (NAFLD) is rapidly becoming the most common liver disease worldwide, yet the pathogenesis of NAFLD is only partially understood. Here, we investigated the role of the gut bacteria in NAFLD by stimulating the gut bacteria via feeding mice the fermentable dietary fiber guar gum and suppressing the gut bacteria via chronic oral administration of antibiotics. Guar gum feeding profoundly altered the gut microbiota composition, in parallel with reduced diet-induced obesity and improved glucose tolerance. Strikingly, despite reducing adipose tissue mass and inflammation, guar gum enhanced hepatic inflammation and fibrosis, concurrent with markedly elevated plasma and hepatic bile acid levels. Consistent with a role of elevated bile acids in the liver phenotype, treatment of mice with taurocholic acid stimulated hepatic inflammation and fibrosis. In contrast to guar gum, chronic oral administration of antibiotics effectively suppressed the gut bacteria, decreased portal secondary bile acid levels, and attenuated hepatic inflammation and fibrosis. Neither guar gum or antibiotics influenced plasma lipopolysaccharide levels. In conclusion, our data indicate a causal link between changes in gut microbiota and hepatic inflammation and fibrosis in a mouse model of NAFLD, possibly via alterations in bile acids.
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:We report the genes regulated during citrate fermentation. Examination of 5 different time points during fermentation in Aspergillus niger H915-1.
Project description:The aim of this study was to investigate the regulatory role of Aspergillus niger AmyR and InuR during growth on inulin and sucrose
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: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:Using transcriptomics, the strain-specific metabolism was mapped for two whole-genome sequenced strains of Aspergillus niger Keywords: Strain comparison
Project description:Expression data from batch cultivations of Aspergillus niger wild type strain ATCC 1015 and adrA, facB and creA deletion mutants constructed on ATCC 1015 background strain with glucose or glycerol as carbon sources. Genome-wide transcriptome analysis was used to identify genes either affected directly or indirectly by each transcription factor investigated during growth on a repressing or a derepressing carbon source. For this purpose, batch cultivations under well-controlled conditions were performed with Aspergillus niger wild type strain ATCC 1015 and the three deletion mutants of the corresponding transcription factors AdrA, FacB and CreA. Samples for RNA extraction were collected and further processed for hybridization in custom-designed Affymetrix microarrays containing probes for three Aspergillus species, including A. niger.
Project description:Galactose catabolism in Aspergillus nidulans is regulated by at least two regulators, GalR and GalX. In Aspergillus niger only GalX is present, and its role in D-galactose catabolism in this fungus was investigated. Phenotypic and gene expression analysis of a wild type and a galX disruptant revealed that GalX does not substitute for the absence of GalR in A. niger, it regulates the D-galactose oxido-reductive pathway, but not the Leloir pathway. Four genes, including the recently characterized ladB (galactitol dehydrogenase) were found to have differencial expressions that are highly relevant to GalX , indicating a novel oxido-reductive pathway in A.niger .