Sugar-dependent gene expression in xylose grown A. thaliana cell suspension culture
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
SUBMITTER: Leszek Kleczkowski
PROVIDER: E-GEOD-57751 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:To investigate whether the transcriptional response to carbon (C) depletion and sucrose re-addition depend on the duration of C-depletion, Arabidopsis thaliana seedlings growing in liquid culture in weak continuous light were harvested 3, 6, 12, 24, 48 and 72 h after removing sucrose from the medium, and 30 min after resupplying sucrose at each of these times. After removing sucrose, soluble sugars fell strongly within 3 h, and starch was gradually depleted over 24 h, and hexose phosphates and ATP declined gradually over 72 h. Expression profiling using ATH arrays pointed to Overall the transcriptional response pointed to early transcriptional remodelling of metabolism to conserve C, followed by induction of photosynthesis and pathways that recycle C, and repression of growth-related processes. The time-dependent transcriptional response to C-depletion differed from that during a light/dark cycle and an extended night. Re-supplying sucrose for 30 min led to near-complete recovery of seedling sucrose levels, partial recovery of reducing sugars and phosphorylated intermediates, but no immediate change of starch or ATP. The rapid transcriptional response to sucrose readdition was conserved across the entire C-depletion time course, became larger with time. , and was highly enriched for regulatory genes. Whilst there was a rapid decrease of many C-depletion-induced transcripts, fewer transcripts increased. The majority of the transcripts that responded rapidly after resupplying sucrose also decreased after treating C-depleted seedlings with the transcriptional inhibitor cordycepin A, pointing to an important role for transcript turnover in the rapid response to sucrose.
2015-10-12 | E-MTAB-3143 | biostudies-arrayexpress
Project description:This proposed study is designed to investigate the specific uptake of fructose by human colorectal tumors. In this study, subjects with colorectal cancer undergoing surgery will receive an oral sugar solution containing fructose or xylose prior to surgery. The tumor will then be resected, and a portion of the tissue will be used to measure the abundance of fructose and xylose. The study hypothesis is that the tumors will take up fructose sugar but not xylose sugar. A comparison of the sugar uptake between the tumor and normal tissues from the adjacent intestinal epithelium and smooth muscle and the liver will be conducted. This proposal will confirm that human colorectal cancer tumors can directly absorb dietary sugars, which has never been demonstrated.
| 2396702 | ecrin-mdr-crc
Project description:Though highly efficient at fermenting hexose sugars, the ethanologenic yeast Saccharomyces cerevisiae has limited ability to ferment five-carbon sugars. As a significant portion of sugars found in cellulosic biomasses is the five carbon sugar xylose, S. cerevisiae must be engineered to metabolize pentose sugars. Here we combined classical candidate gene approach with systems biology to develop xylose-utilising S. cerevisiae strains. The introduction of an exogenous xylose isomerase (XYLA) and an additional copy of the endogenous xylulokinase gene (XKS1) results in the significant improvement of xylose consumption. Microarray studies reveal that the introduction of XYLA and XKS1 results in the dramatic transcriptional remodelling of the cell under both glucose and xylose conditions. To further investigate the cellular processes impacted by the introduction of XYLA and XKS1, using genome-wide chemical and synthetic lethal screens we identified greater than 40 deletion mutants that impact xylose utilization. We identified four genes, ALP1, ISC1, RPL20B and BUD21, that when individually deleted allow S. cerevisiae to utilize xylose as the sole carbon source. When these mutants are combined with XYLA and XKS1, it results in strains with significant improvement in xylose consumption. We have demonstrated that systems biology techniques combined with candidate gene approaches can successfully lead to novel genetic strategies for the improvement of xylose utilization
2012-07-15 | GSE27325 | GEO
Project description:Though highly efficient at fermenting hexose sugars, the ethanologenic yeast Saccharomyces cerevisiae has limited ability to ferment five-carbon sugars. As a significant portion of sugars found in cellulosic biomasses is the five carbon sugar xylose, S. cerevisiae must be engineered to metabolize pentose sugars. Here we combined classical candidate gene approach with systems biology to develop xylose-utilising S. cerevisiae strains. The introduction of an exogenous xylose isomerase (XYLA) and an additional copy of the endogenous xylulokinase gene (XKS1) results in the significant improvement of xylose consumption. Microarray studies reveal that the introduction of XYLA and XKS1 results in the dramatic transcriptional remodelling of the cell under both glucose and xylose conditions. To further investigate the cellular processes impacted by the introduction of XYLA and XKS1, using genome-wide chemical and synthetic lethal screens we identified greater than 40 deletion mutants that impact xylose utilization. We identified four genes, ALP1, ISC1, RPL20B and BUD21, that when individually deleted allow S. cerevisiae to utilize xylose as the sole carbon source. When these mutants are combined with XYLA and XKS1, it results in strains with significant improvement in xylose consumption. We have demonstrated that systems biology techniques combined with candidate gene approaches can successfully lead to novel genetic strategies for the improvement of xylose utilization For this experiment samples (2 reference and 2 test samples), consisting of at least 3 biological reps were hybridized. Cy3 one-color labelling was used for each sample.
2012-07-14 | E-GEOD-27325 | biostudies-arrayexpress
Project description:Saccharomyces cerevisiae cannot metabolize non-glucose sugars including cellobiose, xylose, xylodextrins in nature, which are prevalent in plant cell wall. Here, one engineered S. cerevisiae strain, which expresses a cellodextrin transporter gene (cdt-1) and an intracellular β-glucosidase gene (codon-optimized gh1-1) from Neurospora crassa; XYL1 (xylose reductase gene), XYL2 (xylitol dehydrogenase gene), and XKS1 (xylulose kinase gene) from Scheffersomyces stipitis, as well as cdt-2 (coding for cellodextrin transporter 2), gh43-2 (coding for β-xylosidase) and gh43-7 (coding for a xylosyl-xylitol-specific β-xylosidase) from N. crassa, can utilize the above non-glucose sugars. We sequenced mRNA from exponential cultures of the engineered S. cerevisiae grown on glucose, cellobiose, xylose or xylodextrins as a single carbon source in both aerobic and anaerobic conditions in biological triplicate. Differences in gene expression between non-glucose sugar and glucose metabolism revealed by RNA deep sequencing indicated that non-glucose sugar metabolism induced mitochondrial activation and reduced amino acid and protein biosynthesis under fermentation conditions.
2021-05-27 | GSE69404 | GEO
Project description:Sulfolobus acidocaldarius has been previously reported to grow on a broad range of sugars, but there is limited information on the ability of the organism to metabolize multiple sugars simultaneously. We report here the ability of S. acidocaldarius to utilize glucose and xylose simultaneously without di-auxie effect. The organism utilized a mixture of 1 g/L glucose and 1 g/L xylose with a growth rate of 0.079 h-1 compared to 0.074 h-1 and 0.22 h-1 when the organism was grown on xylose 2 g/L and 2 g/L glucose respectively as sole carbon sources. An increase in xylose concentration to 2 and 4 g/L in a medium containing 1 g/L glucose resulted in a growth rate of 0.082 and 0.085 h-1. However, increasing glucose concentration by 2 and 4 g/L when xylose concentration was maintained at 1 g/L decreased the growth rate to 0.062 and 0.052 h-1 respectively. S. acidocaldarius appeared to be utilizing the sugars at a rate roughly proportional to their concentration in the medium, resulting in complete utilization of these sugars at same time. The organism did not show preference for either glucose or xylose when it was grown on both sugars. Similar results were obtained with a combination of glucose, arabinose and galactose. These observations strongly suggest that S. acidocaldarius does not regulate utilization of the sugars tested herein using carbon catabolite repression (CCR) commonly found in most bacteria. The mechanism by which the organism utilized a mixture of sugar is yet to be elucidated. However, we were able to identify genes encoding for the putative glucose ABC transporters; but the putative xylose transporter was not identified.
2010-07-31 | GSE21695 | GEO
Project description:Sulfolobus acidocaldarius has been previously reported to grow on a broad range of sugars, but there is limited information on the ability of the organism to metabolize multiple sugars simultaneously. We report here the ability of S. acidocaldarius to utilize glucose and xylose simultaneously without di-auxie effect. The organism utilized a mixture of 1 g/L glucose and 1 g/L xylose with a growth rate of 0.079 h-1 compared to 0.074 h-1 and 0.22 h-1 when the organism was grown on xylose 2 g/L and 2 g/L glucose respectively as sole carbon sources. An increase in xylose concentration to 2 and 4 g/L in a medium containing 1 g/L glucose resulted in a growth rate of 0.082 and 0.085 h-1. However, increasing glucose concentration by 2 and 4 g/L when xylose concentration was maintained at 1 g/L decreased the growth rate to 0.062 and 0.052 h-1 respectively. S. acidocaldarius appeared to be utilizing the sugars at a rate roughly proportional to their concentration in the medium, resulting in complete utilization of these sugars at same time. The organism did not show preference for either glucose or xylose when it was grown on both sugars. Similar results were obtained with a combination of glucose, arabinose and galactose. These observations strongly suggest that S. acidocaldarius does not regulate utilization of the sugars tested herein using carbon catabolite repression (CCR) commonly found in most bacteria. The mechanism by which the organism utilized a mixture of sugar is yet to be elucidated. However, we were able to identify genes encoding for the putative glucose ABC transporters; but the putative xylose transporter was not identified. A study of S. acidocaldarius grown in glucose, xylose, or the two carbon sources combined in mid-log. Analyzed on Nimblegen 4-plex S. acidocaldarius DSM 639 array weblink: http://microbesonline.org/cgi-bin/microarray/viewExp.cgi?expId=1723
2010-07-31 | E-GEOD-21695 | biostudies-arrayexpress
Project description:Sugars modulate expression of hundreds of genes in plants. Previous studies on sugar signaling, using intact plants or plant tissues, were hampered by tissue heterogeneity, uneven sugar transport and/or inter-conversions of the applied sugars. This, in turn, could obscure the identity of a specific sugar that acts as a signal affecting expression of given gene in a given tissue or cell-type. To bypass those biases, we have developed a novel biological system, based on stem-cell-like Arabidopsis suspension culture. The cells were grown in a hormone-free medium and were sustained on xylose as the only carbon source. The functional genomics approach was used to identify sugar responsive genes, which rapidly (within 1 h) respond specifically to low concentration (1 mM) of glucose, fructose and/or sucrose.
2014-05-16 | GSE57751 | GEO
Project description:Background Lignocellulosic biomass is a promising renewable feedstock for biofuel production. Acetate is one of the major inhibitors liberated from hemicelluloses during hydrolysis. An understanding of the toxic effects of acetate on the fermentation microorganism and the efficient utilization of mixed sugars of glucose and xylose in the presence of hydrolysate inhibitors is crucial for economic biofuel production. Results A new microarray was designed including both coding sequences and intergenic regions to investigate the acetate stress responses of Zymomonas mobilis 8b when using single carbon sources of glucose or xylose, or mixed sugars of both glucose and xylose. With the supplementation of exogenous acetate, 8b can utilize all the glucose with a similar ethanol yield, although the growth, final biomass, and ethanol production rate were reduced. However, xylose utilization was inhibited in both media containing xylose or a mixed sugar of glucose and xylose, although the performance of 8b was better in mixed sugar than xylose-only media. The presence of acetate caused genes related to biosynthesis, the flagellar system, and glycolysis to be downregulated, and genes related to stress responses and energy metabolism to be upregulated. Unexpectedly, xylose seems to pose more stress on 8b, recruiting more genes for xylose utilization, than does acetate. Several gene candidates based on transcriptome results were selected for genetic manipulation, and a TonB-dependent receptor knockout mutant was confirmed to have a slight advantage regarding acetate tolerance. Conclusions Our results indicate Z. mobilis utilized a different mechanism for xylose utilization, with an even more severe impact on Z. mobilis than that caused by acetate treatment. Our study also suggests redox imbalance caused by stressful conditions may trigger a metabolic reaction leading to the accumulation of toxic intermediates such as xylitol, but Z. mobilis manages its carbon and energy metabolism through the control of individual reactions to mitigate the stressful conditions. We have thus provided extensive transcriptomic datasets and gained insights into the molecular responses of Z. mobilis to the inhibitor acetate when grown in different sugar sources, which will facilitate future metabolic modeling studies and strain improvement efforts for better xylose utilization and acetate tolerance.
2014-09-08 | GSE57553 | GEO
Project description:Background: Lignocellulosic biomass is a promising renewable feedstock for the microbial production of fuels. To release the major fermentable sugars such as glucose and xylose, pretreatment and enzymatic hydrolysis of biomass feedstock are needed. During this process, many toxic compounds are produced or introduced which subsequently inhibit microbial growth and eventually the production rate and yield. Acetate is one of the major inhibitors liberated from hemicelluloses during dilute acid pretreatment. An understanding of the toxic effects of acetate on the fermentation microorganism is critical to improving biofuel yields in the process. In addition, the efficient utilization of mixed sugars of glucose and xylose in the presence of hydrolysate inhibitors is crucial for economic biofuel production. Results: We have observed previously that some pretreatment inhibitors affect growth and performance in Zymomonas mobilis 8b differently when different sugars (e.g. glucose or xylose) are used as substrate. To investigate this phenomenon at the cellular level, microarray technology was used to investigate the acetate stress responses of Z. mobilis 8b when using single carbon sources of glucose or xylose, and mixed sugars of glucose and xylose. We designed a microarray based on the most up-to-date genome annotation for both coding sequences and intergenic regions. In the presence of acetate, 8b still can utilize all the glucose (though xylose utilization was inhibited) with similar ethanol yield although the growth, final biomass, and ethanol production rate were reduced. The presence of acetate caused genes related to biosynthesis, flagellar system, and glycolysis to be downregulated, and genes related to stress responses and energy metabolism to be upregulated. Our result indicates that Z. mobilis utilized different mechanism for xylose utilization compared to that of glucose, with even more dramatic results than those caused by treatment of the culture with the inhibitor acetate. Our study also suggests that redox imbalance caused by stressful conditions may trigger a metabolic reaction that leads to the accumulation of toxic intermediates such as xylitol, but Z. mobilis appears to be capable of managing its carbon and energy metabolism through the control of individual reactions to overcome the inhibition caused by stressful conditions. Several target gene candidates based on transcriptomic result have been selected for genetic manipulation and a TonB-dependent receptor knockout mutant was confirmed to have advantage on acetate tolerance. Conclusions: We have gained insights into the molecular responses of the model ethanologenic bacterium Z. mobilis to the inhibitor acetate when grown in different sugar sources. These insights will facilitate future metabolic modeling studies and help further strain metabolic engineering efforts for better xylose utilization and acetate tolerance. Two series of microarray studies using total RNA extracted from Zymomonas mobilis subsp mobilis 8b (an xylose-utilizing recombinant) were carried out to investigate the effect of carbon source and acetate on Z. mobilis. One study compared the acetate effect in either glucose or xylose at exponential phase and another study investigated the acetate effect in mixed sugar of glucose and xylose at three growth phases of exponential, transition, and stationary. Tthree biological replicates were used for each condition.
2014-09-08 | E-GEOD-57553 | biostudies-arrayexpress