Evolutionary potential, cross-stress behavior and the genetic basis of acquired stress resistance in Escherichia coli
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ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE39926 | GEO | 2013/02/28
SECONDARY ACCESSION(S): PRJNA172115
REPOSITORIES: GEO
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Project description:We evolved Escherichia coli cells over 500 generations under five environments that include four abiotic stressors: osmotic, acidic, oxidative, n-butanol, and control The goal of the experiment: Bacterial populations have a remarkable capacity to cope with extreme environmental fluctuations in their natural environments. In certain cases, adaptation to one stressful environment provides a fitness advantage when cells are exposed to a second stressor, a phenomenon that has been coined as cross-stress protection. A tantalizing question in bacterial physiology is how the cross-stress behavior emerges during adaptation and what the genetic basis of acquired stress resistance is. RNA profiles were obtained for six E. coli strains evolved for 500 generations under abiotic stressors; two technical replicates for each strain where sequenced by Illumina GAII analyzer
2013-02-28 | E-GEOD-39926 | biostudies-arrayexpress
Project description:n-Butanol has been proposed as an alternative biofuel to ethanol, and both Escherichia coli and Saccharomyces cerevisiae have been engineered to produce it. Unfortunately, n-butanol is more toxic than ethanol to these organisms. To understand the basis for its toxicity, cell wide studies were conducted at the transcript, protein and metabolite levels to obtain a global view of the n-butanol stress response. Analysis of the data indicate that n-butanol stress has components common to other stress responses and includes perturbation in respiratory functions (nuo, cyo operons), oxidative stress (sodC, katG, yqhD), heat shock and cell envelope stress (rpoE, clpB, htpG, degP, cpxPR), metabolite transport (malE, opp operon) and biosynthesis. Inducible expression of the yqhD gene was found to improve the host’s tolerance to exogenous n-butanol and confirms the role of this gene in coping with butanol stress. To survey for other potential candidates that may serve to improve host tolerance, mutant strains in several candidates which show changes at the transcript and protein levels were examined for sensitivity during butanol exposure. Chassis engineering based on these cues may be required in a high production titer, butanol-producing host.
2009-12-31 | GSE16973 | GEO
Project description:Microbes exhibit short and long term responses when exposed to challenging environmental conditions. To what extent these responses are correlated, what their evolutionary potential is and how they translate to cross-stress fitness is still unclear. In this study, we comprehensively characterized the response of Escherichia coli populations to four abiotic stresses (n-butanol, osmotic, acidic, and oxidative) and their combinations by performing genome-scale transcriptional analysis and growth profiling. We performed an analysis of their cross-stress behavior which identified 15 cases of cross- protection and one case of cross vulnerability. To elucidate the evolutionary potential of stress responses to individual stresses and stress combinations, we re-sequenced E. coli populations evolved in those four environments for 500 generations. We developed and applied a network-driven method that integrates mutations and differential expression to identify core and stress-specific gene communities that are likely to have a phenotypic impact. Our results suggest that beyond what is expected from the general stress response mechanisms, cross-stress behavior arises both from common pathways, several including metal ion binding and glycolysis/gluconeogenesis, and stress-specific expression programs. The stress-specific dependences uncovered, argue that cross-stress behavior is ubiquitous and central to understanding microbial physiology under stressful conditions.
2017-05-30 | GSE58325 | GEO
Project description:n-Butanol has been proposed as an alternative biofuel to ethanol, and both Escherichia coli and Saccharomyces cerevisiae have been engineered to produce it. Unfortunately, n-butanol is more toxic than ethanol to these organisms. To understand the basis for its toxicity, cell wide studies were conducted at the transcript, protein and metabolite levels to obtain a global view of the n-butanol stress response. Analysis of the data indicate that n-butanol stress has components common to other stress responses and includes perturbation in respiratory functions (nuo, cyo operons), oxidative stress (sodC, katG, yqhD), heat shock and cell envelope stress (rpoE, clpB, htpG, degP, cpxPR), metabolite transport (malE, opp operon) and biosynthesis. Inducible expression of the yqhD gene was found to improve the hostâs tolerance to exogenous n-butanol and confirms the role of this gene in coping with butanol stress. To survey for other potential candidates that may serve to improve host tolerance, mutant strains in several candidates which show changes at the transcript and protein levels were examined for sensitivity during butanol exposure. Chassis engineering based on these cues may be required in a high production titer, butanol-producing host. This comparison is between E. coli DH1 cells treated with 0.8% n-butanol and untreated cells at 0, 30, 80, and 195 minutes after addition. 3 biological replicates were grown, total RNA was extracted, labeled, and hybridized on 3 slides for each time point. http://www.microbesonline.org/cgi-bin/microarray/viewExp.cgi?expId=1266
2010-05-16 | E-GEOD-16973 | biostudies-arrayexpress
Project description:Clostridium acetobutylicum is a Gram positive, endospore forming firmicute that has been known as the model organims for ABE (acetone-butanol-ethanol) fermentation. With its ability to consume a wide variety of substrates, C. acetobutylicum carries out a biphasic ABE fermentation, which consists of the acidogenic growth phase with the formation of butyric acid and acetic acid, followed by the solventogenic stationary phase with the formation of acetone, butanol and ethanol, characterised by the reassimilation of acids. The production butanol is of renewed ineterest both as a potential biofuel and bulk chemical production. Both butanol and butyrate posses toxic characteristic and here, we focus on understanding and modeling the stress response of C. acetobutylicum to one of the two important toxic metabolites: butanol.
2013-08-20 | GSE48031 | GEO
Project description:Stress leads to important adaptive physiological responses including release of catecholamines from the adrenal medulla. Repeated or prolonged stress increases the propensity for many disorders including cardiovascular disease and neuropsychiatric disorders. The susceptibility to stress is determined by a number of factors including prior experience with stress. It has been found that while there is adaptation to prolonged cold stress; it leads to sensitization when cold stressed animals are exposed to a different (novel) stressor. Our study aims to determine the mechanism of this adaptation and sensitization.,We will determine the gene expression patterns in rat adrenal medulla in response to several times of cold stress. We will also determine the changes in gene expression with single immobilization stress in adrenal medulla of rat with and without preexposure to cold stress to investigate the mechanism of sensitization in cold adapted animals. ,We hypothesize that during the course of cold stress there are alterations in gene expression of several neurotransmitter related genes and transcription factors. In cold adapted animals, there is increased susceptibility to stress due to sustained changes in expression of several transcription factors, such as FRA-2 which lead to an exaggerated response to the novel stressor. ,Rats were exposed to cold stress (4oC) for 1, 7 or 28 days. A parallel group was kept at room temperature (unstressed). Unstressed or rats pre-exposed to 28 days cold were immobilized for 2 hrs and killed by decapitation. The adrenal medullae, separately from right and left side, have been dissected and individually frozen at -70oC. Our recent immunoblots with the tissue from one side revealed that there is increase in tyrosine hydroxylase and c-fos with the short term cold stress and in dopamine beta hydroxylase and Fra-2 even with the prolonged cold stress. The response of several transcription factors to immobilization stress was enhanced in the cold adapted animals. RNA will be prepared with RNAqueous-Micro Isolation kit from Ambion (alternatively we can ship the tissues). We will pool samples from 4 rats per treatment to control for variability.
2007-09-28 | E-GEOD-2875 | biostudies-arrayexpress
Project description:BACKGROUND: With the aim of remaining viable, bacteria must deal with changes in environmental conditions, including increases in external osmolarity. While studies concerning bacterial response to this stress condition have focused on soil, marine and enteric species, this report is about Caulobacter crescentus, a species inhabiting freshwater oligotrophic habitats. RESULTS: A genomic analysis reported in this study shows that most of the classical genes known to be involved in intracellular solute accumulation under osmotic adaptation are missing in C. crescentus. Consistent with this observation, growth assays revealed a restricted capability of the bacterium to propagate under hyperosmotic stress, and addition of the compatible solute glycine betaine did not improve bacterial resistance. A combination of transcriptomic and proteomic analyses indicated quite similar changes triggered by the presence of either salt or sucrose, including down-regulation of many housekeeping processes and up-regulation of functions related to environmental adaptation. Furthermore, a GC-MS analysis revealed some metabolites at slightly increased levels in stressed cells, but none of them corresponding to well-established compatible solutes. CONCLUSION: Despite a clear response to hyperosmotic stress, it seems that the restricted capability of C. crescentus to tolerate this unfavorable condition is probably a consequence of the inability to accumulate intracellular solutes. This finding is consistent with the ecology of the bacterium, which inhabits aquatic environments with low nutrient concentration. Three experimental procedures, each of them performed in three replicates. A total of nine independent biological samples were used
2015-04-21 | E-GEOD-49654 | biostudies-arrayexpress
Project description:Clostridium acetobutylicum is a Gram positive, endospore forming firmicute that has been known as the model organims for ABE (acetone-butanol-ethanol) fermentation. With its ability to consume a wide variety of substrates, C. acetobutylicum carries out a biphasic ABE fermentation, which consists of the acidogenic growth phase with the formation of butyric acid and acetic acid, followed by the solventogenic stationary phase with the formation of acetone, butanol and ethanol, characterised by the reassimilation of acids. The production butanol is of renewed ineterest both as a potential biofuel and bulk chemical production. Both butanol and butyrate posses toxic characteristic and here, we focus on understanding and modeling the stress response of C. acetobutylicum to one of the two important toxic metabolites: butanol. C. acetobutylicum cultures were grown, three biological replicates, to mid-exponential phase and then stressed with four levels of butanol (0 mM - No stress; 30 mM - Low stress; 60 mM - Medium stress; & 90 mM - High stress). Samples were collected following the stress at 0, 15, 30, 45, 60 and 75 min, post stress. These sampling times, which are of the order of the doubling time of these cells, were meant to capture largely the direct and immediate impact of these stresses on gene expression. The RNA extracted from two biological replicates were used for microarray hybridization foloowing cDNA generationa nd labelling using Agilent 44K arrays, while the third was used for q-RT-PCR validation. For each stress level, 6 time points with 2 biological replicates and dye swaps (Cy3/Cy5) were prepared for comparison. The hybridization was perfomed against an equal amount of oppositely labeled cDNA from common reference pool prepared using equal amounts of labeled cDNA from all four stress levels.
2013-08-20 | E-GEOD-48031 | biostudies-arrayexpress
Project description:Metabolite accumulation has pleiotropic, including toxic, effects on cellular physiology, but such effects are not well understood at the genomic level. Using DNA microarrays, the Clostridium acetobutylicum transcriptional stress response to butanol was analyzed. Keywords: stress response
2007-12-29 | GSE5008 | GEO
Project description:Clostridium acetobutylicum is a Gram positive, endospore forming firmicute that has been known as the model organims for ABE (acetone-butanol-ethanol) fermentation. With its ability to consume a wide variety of substrates, C. acetobutylicum carries out a biphasic ABE fermentation, which consists of the acidogenic growth phase with the formation of butyric acid and acetic acid, followed by the solventogenic stationary phase with the formation of acetone, butanol and ethanol, characterised by the reassimilation of acids. The production butanol is of renewed ineterest both as a potential biofuel and bulk chemical production. Both butanol and butyric acid posses toxic characteristic and here, we focus on understanding and modeling the stress response of C. acetobutylicum to one of the two important toxic metabolites: butyric acid.
2013-08-20 | GSE48039 | GEO