scholarly journals Genome-Wide Transcriptional Responses of Escherichia coli K-12 to Continuous Osmotic and Heat Stresses

2008 ◽  
Vol 190 (10) ◽  
pp. 3712-3720 ◽  
Author(s):  
Thusitha S. Gunasekera ◽  
Laszlo N. Csonka ◽  
Oleg Paliy
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
High Temperature ◽  
Osmotic Stress ◽  
Stress Responses ◽  
Transcriptional Responses ◽  
High Osmolarity ◽  
Genome Wide ◽  
K 12 ◽  
And Oxidative Stress

ABSTRACT Osmotic stress is known to increase the thermotolerance and oxidative-stress resistance of bacteria by a mechanism that is not adequately understood. We probed the cross-regulation of continuous osmotic and heat stress responses by characterizing the effects of external osmolarity (0.3 M versus 0.0 M NaCl) and temperature (43°C versus 30°C) on the transcriptome of Escherichia coli K-12. Our most important discovery was that a number of genes in the SoxRS and OxyR oxidative-stress regulons were up-regulated by high osmolarity, high temperature, or a combination of both stresses. This result can explain the previously noted cross-protection of osmotic stress against oxidative and heat stresses. Most of the genes shown in previous studies to be induced during the early phase of adaptation to hyperosmotic shock were found to be also overexpressed under continuous osmotic stress. However, there was a poorer overlap between the heat shock genes that are induced transiently after high temperature shifts and the genes that we found to be chronically up-regulated at 43°C. Supplementation of the high-osmolarity medium with the osmoprotectant glycine betaine, which reduces the cytoplasmic K+ pool, did not lead to a universal reduction in the expression of osmotically induced genes. This finding does not support the hypothesis that K+ is the central osmoregulatory signal in Enterobacteriaceae.

Effect of anaerobic and stationary phase growth conditions on the heat shock and oxidative stress responses in Escherichia coli K-12

2006 ◽  
Vol 185 (6) ◽  
pp. 429-438 ◽  
Author(s):  
Alondra Díaz-Acosta ◽  
María L. Sandoval ◽  
Luis Delgado-Olivares ◽  
Jorge Membrillo-Hernández
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Heat Shock ◽  
Stationary Phase ◽  
Stress Responses ◽  
Growth Conditions ◽  
Phase Growth ◽  
K 12 ◽  
Oxidative Stress Responses ◽  
And Oxidative Stress

scholarly journals Impact of Nutritional Factors on the Proteome of Intestinal Escherichia coli: Induction of OxyR-Dependent Proteins AhpF and Dps by a Lactose-Rich Diet

2012 ◽  
Vol 78 (10) ◽  
pp. 3580-3591 ◽  
Author(s):  
Monique Rothe ◽  
Carl Alpert ◽  
Wolfram Engst ◽  
Stephanie Musiol ◽  
Gunnar Loh ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Osmotic Stress ◽  
Stress Responses ◽  
Luciferase Reporter ◽  
Nutritional Factors ◽  
Content Type ◽  
E Coli ◽  
K 12 ◽  
The Impact

ABSTRACTTo study the impact of nutritional factors on protein expression of intestinal bacteria, gnotobiotic mice monoassociated withEscherichia coliK-12 were fed three different diets: a diet rich in starch, a diet rich in nondigestible lactose, and a diet rich in casein. Two-dimensional gel electrophoresis and electrospray-tandem mass spectrometry were used to identify differentially expressed proteins of bacteria recovered from small intestine and cecum. Oxidative stress response proteins such as AhpF, Dps, and Fur, all of which belong to the oxyR regulon, were upregulated inE. coliisolates from mice fed the lactose-rich diet. Luciferase reporter gene assays demonstrated that osmotic stress caused by carbohydrates led to the expression ofahpCFanddps, which was not observed in anE. coliΔoxyRmutant. Growth ofahpCFandoxyRdeletion mutants was strongly impaired when nondigestible sucrose was present in the medium. The wild-type phenotype could be restored by complementation of the deletions with plasmids containing the corresponding genes and promoters. The results indicate that some OxyR-dependent proteins play a major role in the adaptation ofE. colito osmotic stress. We conclude that there is an overlap of osmotic and oxidative stress responses. Mice fed the lactose-rich diet possibly had a higher intestinal osmolality, leading to the upregulation of OxyR-dependent proteins, which enable intestinalE. colito better cope with diet-induced osmotic stress.

scholarly journals Genome-Wide Transcriptional Response to Varying RpoS Levels in Escherichia coli K-12

2017 ◽  
Vol 199 (7) ◽  
Author(s):  
Garrett T. Wong ◽  
Richard P. Bonocora ◽  
Alicia N. Schep ◽  
Suzannah M. Beeler ◽  
Anna J. Lee Fong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Stress Responses ◽  
Sigma Factor ◽  
Core Promoter ◽  
Transcriptional Responses ◽  
Content Type ◽  
Cellular Processes ◽  
K 12 ◽  
Sigma Factor Rpos

ABSTRACT The alternative sigma factor RpoS is a central regulator of many stress responses in Escherichia coli. The level of functional RpoS differs depending on the stress. The effect of these differing concentrations of RpoS on global transcriptional responses remains unclear. We investigated the effect of RpoS concentration on the transcriptome during stationary phase in rich media. We found that 23% of genes in the E. coli genome are regulated by RpoS, and we identified many RpoS-transcribed genes and promoters. We observed three distinct classes of response to RpoS by genes in the regulon: genes whose expression changes linearly with increasing RpoS level, genes whose expression changes dramatically with the production of only a little RpoS (“sensitive” genes), and genes whose expression changes very little with the production of a little RpoS (“insensitive”). We show that sequences outside the core promoter region determine whether an RpoS-regulated gene is sensitive or insensitive. Moreover, we show that sensitive and insensitive genes are enriched for specific functional classes and that the sensitivity of a gene to RpoS corresponds to the timing of induction as cells enter stationary phase. Thus, promoter sensitivity to RpoS is a mechanism to coordinate specific cellular processes with growth phase and may also contribute to the diversity of stress responses directed by RpoS. IMPORTANCE The sigma factor RpoS is a global regulator that controls the response to many stresses in Escherichia coli. Different stresses result in different levels of RpoS production, but the consequences of this variation are unknown. We describe how changing the level of RpoS does not influence all RpoS-regulated genes equally. The cause of this variation is likely the action of transcription factors that bind the promoters of the genes. We show that the sensitivity of a gene to RpoS levels explains the timing of expression as cells enter stationary phase and that genes with different RpoS sensitivities are enriched for specific functional groups. Thus, promoter sensitivity to RpoS is a mechanism that coordinates specific cellular processes in response to stresses.

scholarly journals Sulfur and Nitrogen Limitation in Escherichia coli K-12: Specific Homeostatic Responses

2005 ◽  
Vol 187 (3) ◽  
pp. 1074-1090 ◽  
Author(s):  
Prasad Gyaneshwar ◽  
Oleg Paliy ◽  
Jon McAuliffe ◽  
David L. Popham ◽  
Michael I. Jordan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Open Reading Frames ◽  
Mrna Levels ◽  
Growth Responses ◽  
Transcriptional Responses ◽  
Batch Cultures ◽  
Cross Links ◽  
K 12 ◽  
And Oxidative Stress ◽  
Reading Frames

ABSTRACT We determined global transcriptional responses of Escherichia coli K-12 to sulfur (S)- or nitrogen (N)-limited growth in adapted batch cultures and cultures subjected to nutrient shifts. Using two limitations helped to distinguish between nutrient-specific changes in mRNA levels and common changes related to the growth rate. Both homeostatic and slow growth responses were amplified upon shifts. This made detection of these responses more reliable and increased the number of genes that were differentially expressed. We analyzed microarray data in several ways: by determining expression changes after use of a statistical normalization algorithm, by hierarchical and k-means clustering, and by visual inspection of aligned genome images. Using these tools, we confirmed known homeostatic responses to global S limitation, which are controlled by the activators CysB and Cbl, and found that S limitation propagated into methionine metabolism, synthesis of FeS clusters, and oxidative stress. In addition, we identified several open reading frames likely to respond specifically to S availability. As predicted from the fact that the ddp operon is activated by NtrC, synthesis of cross-links between diaminopimelate residues in the murein layer was increased under N-limiting conditions, as was the proportion of tripeptides. Both of these effects may allow increased scavenging of N from the dipeptide d-alanine-d-alanine, the substrate of the Ddp system.

Repressive effect of Rhus coriaria L. fruit extracts on microglial cells-mediated inflammatory and oxidative stress responses

2021 ◽  
Vol 269 ◽  
pp. 113748
Author(s):  
Mohamad Khalil ◽  
Ali Bazzi ◽  
Dana Zeineddine ◽  
Wissam Jomaa ◽  
Ahmad Daher ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Responses ◽  
Microglial Cells ◽  
Fruit Extracts ◽  
Repressive Effect ◽  
Rhus Coriaria ◽  
Oxidative Stress Responses ◽  
And Oxidative Stress

scholarly journals Crosstalk between endoplasmic reticulum stress and oxidative stress: a dynamic duo in multiple myeloma

2021 ◽  
Author(s):  
Sinan Xiong ◽  
Wee-Joo Chng ◽  
Jianbiao Zhou
Keyword(s):  
Oxidative Stress ◽  
Multiple Myeloma ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Cell Fate ◽  
Stress Responses ◽  
Plasma Cells ◽  
Reactive Oxygen Species Generation ◽  
Future Research ◽  
And Oxidative Stress

AbstractUnder physiological and pathological conditions, cells activate the unfolded protein response (UPR) to deal with the accumulation of unfolded or misfolded proteins in the endoplasmic reticulum. Multiple myeloma (MM) is a hematological malignancy arising from immunoglobulin-secreting plasma cells. MM cells are subject to continual ER stress and highly dependent on the UPR signaling activation due to overproduction of paraproteins. Mounting evidence suggests the close linkage between ER stress and oxidative stress, demonstrated by overlapping signaling pathways and inter-organelle communication pivotal to cell fate decision. Imbalance of intracellular homeostasis can lead to deranged control of cellular functions and engage apoptosis due to mutual activation between ER stress and reactive oxygen species generation through a self-perpetuating cycle. Here, we present accumulating evidence showing the interactive roles of redox homeostasis and proteostasis in MM pathogenesis and drug resistance, which would be helpful in elucidating the still underdefined molecular pathways linking ER stress and oxidative stress in MM. Lastly, we highlight future research directions in the development of anti-myeloma therapy, focusing particularly on targeting redox signaling and ER stress responses.

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