Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1288391 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Caldicellulosiruptor saccharolyticus is an extremely thermophilic, Gram-positive anaerobe, which ferments cellulose-, hemicellulose- and pectin-containing biomass to acetate, CO2 and hydrogen. Its broad substrate range, high hydrogen-producing capacity, and ability to co-utilize glucose and xylose, make this bacterium an attractive candidate for microbial bioenergy production. Glycolytic pathways and an ABC-type sugar transporter were significantly up-regulated during growth on glucose and xylose, indicating that C. saccharolyticus co-ferments these sugars unimpeded by glucose-based catabolite repression. The capacity to simultaneously process and utilize a range of carbohydrates associated with biomass feedstocks represents a highly desirable feature of a lignocellulose-utilizing, biofuel-producing bacterium. Keywords: substrate response
2008-04-15 | GSE11153 | GEO
Project description:Ettlia oleoabundans is a triacylglyceride-producing chlorophyte. We investigated gene expression and lipid changes after 6 days under varying concentrations of nitrate and NaCl.
2017-02-15 | GSE78006 | GEO
Project description:Caldicellulosiruptor saccharolyticus is an extremely thermophilic, gram-positive anaerobe which ferments a broad range of substrates to mainly acetate, CO2, and hydrogen gas (H2). Its high hydrogen-producing capacity make this bacterium an attractive candidate for microbial biohydrogen production. However, increased H2 levels tend to inhibit hydrogen formation and leads to the formation of other reduced end products like lactate and ethanol. To investigate the organism’s strategy for dealing with elevated H2 levels and to identify alternative pathways involved in the disposal of the reducing equivalents, the effect of the hydrogen partial pressure (PH2) on fermentation performance was studied. For this purpose cultures were grown under high and low PH2 in a glucose limited chemostat setup. Transcriptome analysis revealed the up-regulation of genes involved in the disposal of reducing equivalents under high PH2, like lactate dehydrogenase and alcohol dehydrogenase as well as the NADH-dependent and ferredoxin-dependent hydrogenases. These findings were in line with the observed shift in fermentation profiles from acetate production under low PH2 to a mixed production of acetate, lactate and ethanol under high PH2. In addition, differential transcription was observed for genes involved in carbon metabolism, fatty acid biosynthesis and several transport systems. The presented transcription data provides experimental evidence for the involvement of the redox sensing Rex protein in gene regulation under high PH2 cultivation conditions. Overall, these findings indicate that the PH2 dependent changes in the fermentation pattern of C. saccharolyticus are, in addition to the known regulation at the enzyme/metabolite level, also regulated at the transcription level.
2013-08-28 | GSE40430 | GEO
Project description:Caldicellulosiruptor saccharolyticus is an extremely thermophilic, Gram-positive anaerobe, which ferments cellulose-, hemicellulose- and pectin-containing biomass to acetate, CO2 and hydrogen. Its broad substrate range, high hydrogen-producing capacity, and ability to co-utilize glucose and xylose, make this bacterium an attractive candidate for microbial bioenergy production. Glycolytic pathways and an ABC-type sugar transporter were significantly up-regulated during growth on glucose and xylose, indicating that C. saccharolyticus co-ferments these sugars unimpeded by glucose-based catabolite repression. The capacity to simultaneously process and utilize a range of carbohydrates associated with biomass feedstocks represents a highly desirable feature of a lignocellulose-utilizing, biofuel-producing bacterium. Keywords: substrate response C. saccharolyticus was subcultured (overnight) 3 times on the substrate of interest in modified DSMZ 640 medium before inoculating a pH-controlled (pH = 7) 1-liter fermentor containing 4 gram substrate per liter. Cells were grown at 70 °C until mid-logarithmic phase (~OD660 = 0.3-0.4) and harvested by centrifugation and rapid cooling to 4 °C and stored at -80 °C. To elucidate the central carbon metabolic pathways and their regulation, transcriptome analysis was performed after growth on glucose, xylose and a 1:1 mixture of both substrates. L-Rhamnose, which was likely to follow another pathway, was used as a reference substrate.
2008-04-15 | E-GEOD-11153 | biostudies-arrayexpress
Project description:This experiment aimed to understand stress responses of microbial communities differing in chronic exposure to the photosynthesis inhibitor diuron, combining untargeted metatranscriptomics (RNA-seq) and dose-response design. First, river microbial communities were incubated for 5-weeks in microcosms 1/ under constant exposure to 4µg/L of diuron (stressed community) or 2/ without contamination (non-stressed community). Then, both communities were exposed for 1 hour to a gradient of diuron concentrations to investigate differences in stress responses after chronic exposure. This experimental design enabled the determination of contig response trends as well as sensitivity thresholds.
2025-04-01 | GSE201034 | GEO
Project description:Caldicellulosiruptor saccharolyticus is an extremely thermophilic, gram-positive anaerobe which ferments a broad range of substrates to mainly acetate, CO2, and hydrogen gas (H2). Its high hydrogen-producing capacity make this bacterium an attractive candidate for microbial biohydrogen production. However, increased H2 levels tend to inhibit hydrogen formation and leads to the formation of other reduced end products like lactate and ethanol. To investigate the organismM-bM-^@M-^Ys strategy for dealing with elevated H2 levels and to identify alternative pathways involved in the disposal of the reducing equivalents, the effect of the hydrogen partial pressure (PH2) on fermentation performance was studied. For this purpose cultures were grown under high and low PH2 in a glucose limited chemostat setup. Transcriptome analysis revealed the up-regulation of genes involved in the disposal of reducing equivalents under high PH2, like lactate dehydrogenase and alcohol dehydrogenase as well as the NADH-dependent and ferredoxin-dependent hydrogenases. These findings were in line with the observed shift in fermentation profiles from acetate production under low PH2 to a mixed production of acetate, lactate and ethanol under high PH2. In addition, differential transcription was observed for genes involved in carbon metabolism, fatty acid biosynthesis and several transport systems. The presented transcription data provides experimental evidence for the involvement of the redox sensing Rex protein in gene regulation under high PH2 cultivation conditions. Overall, these findings indicate that the PH2 dependent changes in the fermentation pattern of C. saccharolyticus are, in addition to the known regulation at the enzyme/metabolite level, also regulated at the transcription level. Two conditions: low H2 partial pressure and high H2 partial pressure, both at steady state growth were harvested for a dye-flip microarray experimental design. Biological replicates were harvested for both conditions and combined prior to cDNA synthesis. Both conditions were labeled with cy3 and cy5 dyes allowing for a technical replicate of hybridization in addition to the biological replicates.
2013-08-28 | E-GEOD-40430 | biostudies-arrayexpress
Project description:Increasing atmospheric CO2 concentrations are causing decreased pH over vast expanses of the ocean. This decreasing pH may alter biogeochemical cycling of carbon and nitrogen via the microbial process of nitrification, a key process that couples these cycles in the ocean, but which is often sensitive to acidic conditions. Recent reports indicate a decrease in oceanic nitrification rates under experimentally lowered pH. How composition and abundance of ammonia oxidizing bacteria (AOB) and archaea (AOA) assemblages respond to decreasing oceanic pH, however, is unknown. We sampled microbes from two different acidification experiments and used a combination of qPCR and functional gene microarrays for the ammonia monooxygenase gene (amoA) to assess how acidification alters the structure of ammonia oxidizer assemblages. We show that despite widely different experimental conditions, acidification consistently altered the community composition of AOB by increasing the relative abundance of taxa related to the Nitrosomonas ureae clade. In one experiment this increase was sufficient to cause an increase in the overall abundance of AOB. There were no systematic shifts in the community structure or abundance of AOA in either experiment. These different responses to acidification underscore the important role of microbial community structure in the resiliency of marine ecosystems. SUBMITTER_CITATION: Title: Acidification alters the composition of ammonia oxidizing microbial assemblages in marine mesocosms Journal: Marine Ecology Progress Series Issue: 492 Pages: 1-8 DOI: 10.3354/meps 10526 Authors: Jennifer L Bowen Patrick J Kearns Michael Holcomb Bess B Ward
2013-08-27 | GSE49956 | GEO
Project description:The principles governing acquisition and interspecies exchange of nutrients in microbial communities and how those exchanges impact community productivity are poorly understood. Here, we examine energy and macronutrient acquisition in unicyanobacterial consortia for which species-resolved genome information exists for all members, allowing us to use multi-omic approaches to predict species’ abilities to acquire resources and examine expression of resource-acquisition genes during succession. Metabolic reconstruction indicated that a majority of heterotrophic community members lacked the genes required to directly acquire the inorganic nutrients provided in culture medium, suggesting high metabolic interdependency. The sole primary producer in consortium UCC-O, cyanobacterium Phormidium sp. OSCR, displayed declining expression of energy harvest, carbon fixation, and nitrate and sulfate reduction proteins but sharply increasing phosphate transporter expression over 28 days. Most heterotrophic members likewise exhibited signs of phosphorus starvation during succession. Though similar in their responses to phosphorus limitation, heterotrophs displayed species-specific expression of nitrogen acquisition genes. These results suggest niche partitioning around nitrogen sources may structure the community when organisms directly compete for limited phosphate. Such niche complementarity around nitrogen sources may increase community diversity and productivity in phosphate-limited phototrophic communities.
2017-05-24 | GSE99220 | GEO
Project description:We were interested in investigating the transcriptome responses to exogenous applications of brassinosteroid hormone when Arabidopsis seedlings are pre-stressed with a reactive oxygen species, hydrogen peroxide. We were interested in seeing which subsets of BR-responsive gene transcripts were most affected and how BR-responsive gene transcripts responded to increasing concentrations of hydrogen peroxide both as a whole and individually. Liquid culture Arabidopsis seedlings are grown under standard conditions. Hydrogen peroxide is added at various concentrations to pre-stress the seedlings. Following this pretreatment, the seedlings are then treated with brassinosteroid (BR) hormone (epi-brassinolide, BL). Following this treatment, seedlings are harvested and total RNA is extracted for genome-wide transcriptome analysis.
2011-02-28 | E-GEOD-20756 | biostudies-arrayexpress