Transcription profiling of Aspergillus niger amyR and wild type strains grown in maltose and xylose
Ontology highlight
ABSTRACT:
ORGANISM(S): Aspergillus niger
SUBMITTER: Xiaolian Yuan
PROVIDER: E-TABM-324 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Microarray experiments were performed for identifying genes that are involved in inulin and sucrose metabolism by analyzing the transcriptomes of wild type strain N402 and inuR deletion strain grown in sucrose, as well as by analyzing the transcriptomes of wild type strain N402 grown in sucrose and xylose.
2008-06-01 | E-TABM-319 | biostudies-arrayexpress
Project description:Prolonged cultivation (>25 generations) of Saccharomyces cerevisiae in aerobic, maltose-limited chemostat cultures led to profound physiological changes. Maltose hypersensitivity was observed when cells from prolonged cultivations were suddenly exposed to excess maltose. This substrate hypersensitivity was evident from massive cell lysis and loss of viability. During prolonged cultivation at a fixed specific growth rate, the affinity for the growth-limiting nutrient (i.e., maltose) increased, as evident from a decreasing residual maltose concentration. Furthermore, the capacity of maltose-dependent proton uptake increased up to 2.5-fold during prolonged cultivation. Genome-wide transcriptome analysis showed that the increased maltose transport capacity was not primarily due to increased transcript levels of maltose-permease genes upon prolonged cultivation. We propose that selection for improved substrate affinity (ratio of maximum substrate consumption rate and substrate saturation constant) in maltose-limited cultures leads to selection for cells with an increased capacity for maltose uptake. At the same time, the accumulative nature of maltose-proton symport in S. cerevisiae leads to unrestricted uptake when maltose-adapted cells are exposed to a substrate excess. These changes were retained after isolation of individual cell lines from the chemostat cultures and nonselective cultivation, indicating that mutations were involved. The observed trade-off between substrate affinity and substrate tolerance may be relevant for metabolic engineering and strain selection for utilization of substrates that are taken up by proton symport. Experiment Overall Design: In a recent study (25) we analyzed glucose efflux upon exposure of S. cerevisiae to excess maltose, with yeast cells originating from âyoungâ chemostat cultures (<20 generations). In these experiments no cell lysis was observed upon exposure to excess maltose. However, in further work on this subject, we observed an apparent effect of chemostat culture age on transport capacity. The aim of the present study was to further investigate the effect of prolonged maltose-limited chemostat cultivation on the physiology of S. cerevisiae. To this end we monitored the affinity for maltose, genome-wide transcript levels, activities of key enzymes, and physiological responses to maltose excess during long-term cultivation in maltose-limited chemostat cultures. Experiment Overall Design: Jansen, M. L. A., J. H. de Winde, and J. T. Pronk. 2002. Hxt-carrier-mediated glucose efflux upon exposure of Saccharomyces cerevisiaeSaccharomyces cerevisiae to excess maltose. Appl. Environ. Microbiol. 68:4259-4265.
2008-06-16 | E-GEOD-8897 | biostudies-arrayexpress
Project description:Transcriptional profiling of the A. niger WT (N402) strain treated with xylan (1%, w/v) for 6, 12 and 24 h. The main objective was to identify genes related to cellulases and hemicellulases after treatment with the polysaccharide xylan. The experiment was further validated by enzymatic assays. Three-condition experiment: WT-Xylan for 6, 12 and 24 h at 30oC in batch culture. Firstly, the WT (N402) strain was grown in minimal medium with fructose as carbon source (control), and then transferred to 1% (w/v) xylan as carbon source. 2 biological replicates per time point.
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2008-10-26 | E-GEOD-9402 | biostudies-arrayexpress
Project description:In response to limited nitrogen and abundant carbon sources, diploid Saccharomyces cerevisiae strains undergo a filamentous transition in cell growth as part of pseudohyphal differentiation. Use of the disaccharide maltose as the principal carbon source, in contrast to the preferred nutrient monosaccharide glucose, has been shown to induce a hyper-filamentous growth phenotype in a strain deficient for GPA2 which codes for a Gï¡ protein component that interacts with the glucose-sensing receptor Gpr1p to regulate filamentous growth. In this report, we compare the global transcript and proteomic profiles of wild-type and Gpa2p deficient diploid yeast strains grown on both rich and nitrogen starved maltose media. We find that deletion of GPA2 results in significantly different transcript and protein profiles when switching from rich to nitrogen starvation media. The results are discussed with a focus on the genes associated with carbon utilization, or regulation thereof, and a model for the contribution of carbon sensing/metabolism-based signal transduction to pseudohyphal differentiation is proposed. Experiment Overall Design: For transcriptome profiling, there were 12 Affymetrix Yeast S98 microarrays total. There were four conditions: wildtype MLY61 and gpa2 deletion mutant MLY132 grown in YPM media or transferred to low nitrogen media SLAM. Each condition was done in triplicate, starting with triplicate yeast cultures. Four conditions done in triplicates resulted in 12 samples that went onto 12 microarrays.
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Project description:The filamentous fungus Aspergillus oryzae is an important microbial cell factory for industrial production of useful enzymes, such as α-amylase. In order to optimize the industrial enzyme production process, there is a need to understand fundamental processes underlying protein production, here under how protein production links to metabolism through global regulatory structures. In this study, two α-amylase-producing strains of A. oryzae, a wild type strain and a transformant strain containing additional copies of the α-amylase gene, were characterized at a systematic level. Based on integrated analysis of ome-data together with genome-scale metabolic network and flux calculation, we identified key genes, key enzymes, key proteins, and key metabolites involved in the processes of protein synthesis and secretion, nucleotide metabolism, and amino acid metabolism that can be the potential targets for improving industrial protein production. Keywords: Two Aspergillus oryzae strains and two different carbon sources Two carbon sources (glucose, maltose) with three biological replicates for A. oryzae strain A1560 and strain CF1.1
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Project description:The analysis of fungi secreted proteins has been increasingly employed as a powerful strategy in the prospecting of new catalysts with potential biotechnological application. Since enzyme production is strongly modulated by several factors such as pH, available nutrients, water content, oxygen levels and temperature, the evaluation of growth conditions is of utmost importance to achieve optimal enzyme production. Here, a non-sequenced wood-rotting fungus, L. crinitus, was selected as a model organism for secretome analysis by means of in vitro enzymatic assays and in-depth characterization via proteomics. For enzyme production, the fungus was cultured with several types and concentrations of carbon and nitrogen sources and variable water content. Five different carbon substrates (glucose, maltose, starch, sucrose, carboxymethylcellulose (CMC), glycerol and fructose) and three nitrogen containing compounds (urea, sodium nitrate and ammonium chloride) were used as substitutes of the original carbon and nitrogen sources in culture media. Interestingly, the biomass yield as well as the array of secreted proteins differed drastically under different growing conditions. A mixture of soluble secreted extracts derived from different culture conditions was analyzed both by shotgun mass spectrometry and through protein separation by two-dimensional gel electrophoresis (2DE) prior to identification via LC-MS/MS. Proteins were identified by sequence homology searches using mass spectrometry (MS)-driven BLAST. The spectrum of secreted enzymes comprised various types of CAZymes (carbohydrate-active enzymes), oxidase/reductases, proteases, lipase/esterases, proteins with non-related functions thereby classified as miscellany proteins and hypothetical or unknown predicted proteins. Although pre-separation by 2DE improved the number of identifications (protein map of 150 spots corresponding to 171 identifications) compared to the shotgun approach (98 identifications) both strategies revealed similar distribution of proteins within the functional categories described above. Culture media with reduced water content stimulated the expression of oxidases/reductases such as Lac, MnP, GMC oxidoreductases and glyoxal oxidase while hydrolases were induced during submerged fermentation. The diversity of proteins observed within both the CAZyme and oxidoreductase groups revealed in this fungus a powerful arsenal of enzymes dedicated to the breakdown and consumption of lignocellulose. Moreover, further secretome characterization after sequencing and analysis of the L. crinitus genome can potentially lead to the discovery of novel enzymes of industrial and biotechnological interest. Importantly, information on sequencing data could also reveal novel enzymes which production is strongly stimulated only in specific growing conditions.
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