scholarly journals Stress responses upon starvation and exposure to bacteria in the antFormica exsecta

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6428 ◽  
Author(s):  
Dimitri Stucki ◽  
Dalial Freitak ◽  
Nick Bos ◽  
Liselotte Sundström
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Stress Responses ◽  
Nutritional State ◽  
Oral Exposure ◽  
Starvation Resistance ◽  
Immune Defenses ◽  
Trade Offs ◽  
Induced Changes ◽  
The Impact

Organisms are simultaneously exposed to multiple stresses, which requires regulation of the resistance to each stress. Starvation is one of the most severe stresses organisms encounter, yet nutritional state is also one of the most crucial conditions on which other stress resistances depend. Concomitantly, organisms often deploy lower immune defenses when deprived of resources. This indicates that the investment into starvation resistance and immune defenses is likely to be subject to trade-offs. Here, we investigated the impact of starvation and oral exposure to bacteria on survival and gene expression in the antFormica exsecta. Of the three bacteria used in this study, onlySerratia marcescensincreased the mortality of the ants, whereas exposure toEscherichia coliandPseudomonas entomophilaalleviated the effects of starvation. Both exposure to bacteria and starvation induced changes in gene expression, but in different directions depending on the species of bacteria used, as well as on the nutritional state of the ants.

scholarly journals Starvation resistance and tissue-specific gene expression of stress-related genes in a naturally inbred ant population

2016 ◽  
Vol 3 (4) ◽  
pp. 160062 ◽  
Author(s):  
Nick Bos ◽  
Unni Pulliainen ◽  
Liselotte Sundström ◽  
Dalial Freitak
Keyword(s):  
Gene Expression ◽  
Stress Responses ◽  
Specific Gene ◽  
Starvation Resistance ◽  
Specific Expression ◽  
Tissue Specific ◽  
Trade Offs ◽  
Stress Related Genes ◽  
The Individual ◽  
Different Tissues

Starvation is one of the most common and severe stressors in nature. Not only does it lead to death if not alleviated, it also forces the starved individual to allocate resources only to the most essential processes. This creates energetic trade-offs which can lead to many secondary challenges for the individual. These energetic trade-offs could be exacerbated in inbred individuals, which have been suggested to have a less efficient metabolism. Here, we studied the effect of inbreeding on starvation resistance in a natural population of Formica exsecta ants, with a focus on survival and tissue-specific expression of stress, metabolism and immunity-related genes. Starvation led to large tissue-specific changes in gene expression, but inbreeding had little effect on most of the genes studied. Our results illustrate the importance of studying stress responses in different tissues instead of entire organisms.

scholarly journals Gene expression analysis of Cyanophora paradoxa reveals conserved abiotic stress responses between basal algae and flowering plants

2019 ◽  
Author(s):  
Camilla Ferrari ◽  
Marek Mutwil
Keyword(s):  
Gene Expression ◽  
Stress Responses ◽  
Land Plants ◽  
List Type ◽  
Cyanophora Paradoxa ◽  
Plant Kingdom ◽  
Gene Expression Atlas ◽  
Expression Atlas ◽  
Gene Modules ◽  
The Impact

SummaryThe glaucophyte Cyanophora paradoxa represents the most basal member of the Archaeplastida kingdom, however the function and expression of most of its genes are unknown. This information is needed to uncover how functional gene modules, i.e. groups of genes performing a given function, evolved in the plant kingdom.We have generated a gene expression atlas capturing responses of Cyanophora to various abiotic stresses. This data was included in the CoNekT-Plants database, enabling comparative transcriptomic analyses across two algae and six land plants.We demonstrate how the database can be used to study gene expression, co-expression networks and gene function in Cyanophora, and how conserved transcriptional programs can be identified. We identified gene modules involved in phycobilisome biosynthesis, response to high light and cell division. While we observed no correlation between the number of differentially expressed genes and the impact on growth of Cyanophora, we found that the response to stress involves a conserved, kingdom-wide transcriptional reprogramming, which is activated upon most stresses in algae and land plants.The Cyanophora stress gene expression atlas and the tools found in https://conekt.plant.tools/ database provide a useful resource to reveal functionally related genes and stress responses in the plant kingdom.

scholarly journals The Impact of ackA, pta, and ackA-pta Mutations on Growth, Gene Expression and Protein Acetylation in Escherichia coli K-12

2020 ◽  
Vol 11 ◽  
Author(s):  
Andrea Schütze ◽  
Dirk Benndorf ◽  
Sebastian Püttker ◽  
Fabian Kohrs ◽  
Katja Bettenbrock
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Protein Acetylation ◽  
K 12 ◽  
The Impact

scholarly journals Complex Physiology and Compound Stress Responses during Fermentation of Alkali-Pretreated Corn Stover Hydrolysate by an Escherichia coli Ethanologen

2012 ◽  
Vol 78 (9) ◽  
pp. 3442-3457 ◽  
Author(s):  
Michael S. Schwalbach ◽  
David H. Keating ◽  
Mary Tremaine ◽  
Wesley D. Marner ◽  
Yaoping Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Amino Acids ◽  
Stationary Phase ◽  
Gene Expression Profiling ◽  
Stress Responses ◽  
Expression Profiling ◽  
Content Type ◽  
E Coli ◽  
Cell Maintenance

ABSTRACTThe physiology of ethanologenicEscherichia coligrown anaerobically in alkali-pretreated plant hydrolysates is complex and not well studied. To gain insight into howE. coliresponds to such hydrolysates, we studied anE. coliK-12 ethanologen fermenting a hydrolysate prepared from corn stover pretreated by ammonia fiber expansion. Despite the high sugar content (∼6% glucose, 3% xylose) and relatively low toxicity of this hydrolysate,E. coliceased growth long before glucose was depleted. Nevertheless, the cells remained metabolically active and continued conversion of glucose to ethanol until all glucose was consumed. Gene expression profiling revealed complex and changing patterns of metabolic physiology and cellular stress responses during an exponential growth phase, a transition phase, and the glycolytically active stationary phase. During the exponential and transition phases, high cell maintenance and stress response costs were mitigated, in part, by free amino acids available in the hydrolysate. However, after the majority of amino acids were depleted, the cells entered stationary phase, and ATP derived from glucose fermentation was consumed entirely by the demands of cell maintenance in the hydrolysate. Comparative gene expression profiling and metabolic modeling of the ethanologen suggested that the high energetic cost of mitigating osmotic, lignotoxin, and ethanol stress collectively limits growth, sugar utilization rates, and ethanol yields in alkali-pretreated lignocellulosic hydrolysates.

scholarly journals Transcription Profiling of the Stringent Response in Escherichia coli

2007 ◽  
Vol 190 (3) ◽  
pp. 1084-1096 ◽  
Author(s):  
Tim Durfee ◽  
Anne-Marie Hansen ◽  
Huijun Zhi ◽  
Frederick R. Blattner ◽  
Ding Jun Jin
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Stress Responses ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Stringent Response ◽  
Maximum Growth ◽  
Regulatory Processes ◽  
K 12 ◽  
Encoding Genes

ABSTRACT The bacterial stringent response serves as a paradigm for understanding global regulatory processes. It can be triggered by nutrient downshifts or starvation and is characterized by a rapid RelA-dependent increase in the alarmone (p)ppGpp. One hallmark of the response is the switch from maximum-growth-promoting to biosynthesis-related gene expression. However, the global transcription patterns accompanying the stringent response in Escherichia coli have not been analyzed comprehensively. Here, we present a time series of gene expression profiles for two serine hydroxymate-treated cultures: (i) MG1655, a wild-type E. coli K-12 strain, and (ii) an isogenic relAΔ251 derivative defective in the stringent response. The stringent response in MG1655 develops in a hierarchical manner, ultimately involving almost 500 differentially expressed genes, while the relAΔ251 mutant response is both delayed and limited in scope. We show that in addition to the down-regulation of stable RNA-encoding genes, flagellar and chemotaxis gene expression is also under stringent control. Reduced transcription of these systems, as well as metabolic and transporter-encoding genes, constitutes much of the down-regulated expression pattern. Conversely, a significantly larger number of genes are up-regulated. Under the conditions used, induction of amino acid biosynthetic genes is limited to the leader sequences of attenuator-regulated operons. Instead, up-regulated genes with known functions, including both regulators (e.g., rpoE, rpoH, and rpoS) and effectors, are largely involved in stress responses. However, one-half of the up-regulated genes have unknown functions. How these results are correlated with the various effects of (p)ppGpp (in particular, RNA polymerase redistribution) is discussed.

scholarly journals Extracytoplasmic Function σ Factors as Tools for Coordinating Stress Responses

2021 ◽  
Vol 22 (8) ◽  
pp. 3900
Author(s):  
Rubén de de Dios ◽  
Eduardo Santero ◽  
Francisca Reyes-Ramírez
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Stress Response ◽  
Stress Responses ◽  
Transcription Initiation ◽  
Genomic Context ◽  
General Stress Response ◽  
Functional Studies ◽  
Functional Stress

The ability of bacterial core RNA polymerase (RNAP) to interact with different σ factors, thereby forming a variety of holoenzymes with different specificities, represents a powerful tool to coordinately reprogram gene expression. Extracytoplasmic function σ factors (ECFs), which are the largest and most diverse family of alternative σ factors, frequently participate in stress responses. The classification of ECFs in 157 different groups according to their phylogenetic relationships and genomic context has revealed their diversity. Here, we have clustered 55 ECF groups with experimentally studied representatives into two broad classes of stress responses. The remaining 102 groups still lack any mechanistic or functional insight, representing a myriad of systems yet to explore. In this work, we review the main features of ECFs and discuss the different mechanisms controlling their production and activity, and how they lead to a functional stress response. Finally, we focus in more detail on two well-characterized ECFs, for which the mechanisms to detect and respond to stress are complex and completely different: Escherichia coli RpoE, which is the best characterized ECF and whose structural and functional studies have provided key insights into the transcription initiation by ECF-RNAP holoenzymes, and the ECF15-type EcfG, the master regulator of the general stress response in Alphaproteobacteria.

scholarly journals Regulation of Iron Storage by CsrA Supports Exponential Growth of Escherichia coli

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Christine Pourciau ◽  
Archana Pannuri ◽  
Anastasia Potts ◽  
Helen Yakhnin ◽  
Paul Babitzke ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Escherichia Coli ◽  
Exponential Growth ◽  
Iron Homeostasis ◽  
Iron Storage ◽  
Content Type ◽  
Mrna Targets ◽  
Cellular Iron ◽  
The Impact

ABSTRACT The global regulatory protein CsrA coordinates gene expression in response to physiological cues reflecting cellular stress and nutrition. CsrA binding to the 5′ segments of mRNA targets affects their translation, RNA stability, and/or transcript elongation. Recent studies identified probable mRNA targets of CsrA that are involved in iron uptake and storage in Escherichia coli, suggesting an unexplored role for CsrA in regulating iron homeostasis. Here, we assessed the impact of CsrA on iron-related gene expression, cellular iron, and growth under various iron levels. We investigated five new targets of CsrA regulation, including the genes for 4 ferritin or ferritin-like iron storage proteins (ISPs) and the stress-inducible Fe-S repair protein, SufA. CsrA bound with high affinity and specificity to ftnB, bfr, and dps mRNAs and inhibited their translation, while it modestly activated ftnA expression. Furthermore, CsrA was found to regulate cellular iron levels and support growth by repressing the expression of genes for ISPs, most importantly, ferritin B (FtnB) and bacterioferritin (Bfr). Iron starvation did not substantially affect cellular levels of CsrA or its small RNA (sRNA) antagonists, CsrB and CsrC. csrA disruption led to increased resistance to the lethal effects of H2O2 during exponential growth, consistent with a regulatory role in oxidative stress resistance. We propose that during exponential growth and under minimal stress, CsrA represses the deleterious expression of the ISPs that function under oxidative stress and stationary-phase conditions (FtnB, Bfr, and Dps), thus ensuring that cellular iron is available to processes that are required for growth. IMPORTANCE Iron is an essential micronutrient for nearly all living organisms but is toxic in excess. Consequently, the maintenance of iron homeostasis is a critical biological process, and the genes involved in this function are tightly regulated. Here, we explored a new role for the bacterial RNA binding protein CsrA in the regulation of iron homeostasis. CsrA was shown to be a key regulator of iron storage genes in Escherichia coli, with consequential effects on cellular iron levels and growth. Our findings establish a model in which robust CsrA activity during the exponential phase of growth leads to repression of genes whose products sequester iron or divert it to unnecessary stress response processes. In so doing, CsrA supports E. coli growth under iron-limiting laboratory conditions and may promote fitness in the competitive iron-limited environment of the host large intestine.

scholarly journals The Impact of BPI Expression on Escherichia coli F18 Infection in Porcine Kidney Cells

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2118
Author(s):  
Jian Jin ◽  
Yanjie Huang ◽  
Shouyong Sun ◽  
Zhengchang Wu ◽  
Shenglong Wu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Mrna Level ◽  
Cellular Level ◽  
Porcine Kidney ◽  
Tlr4 Signaling ◽  
E Coli ◽  
Expression Of Genes ◽  
Induced Changes ◽  
The Impact ◽  
Glycosphingolipid Biosynthesis

The efficacy and regulatory activity of bactericidal/permeability-increasing protein (BPI) as a mediator of Escherichia coli (E. coli) F18 resistance remains to be defined. In the present study, we evaluated lipopolysaccharide (LPS)-induced changes in BPI gene expression in porcine kidney (PK15) cells in response to E. coli F18 exposure. We additionally generated PK15 cells that overexpressed BPI to assess the impact of this gene on Toll-like receptor 4 (TLR4) signaling and glycosphingolipid biosynthesis-related genes. Through these analyses, we found that BPI expression rose significantly following LPS exposure in response to E. coli F18ac stimulation (p < 0.01). Colony count assays and qPCR analyses revealed that E. coli F18 adherence to PK15 cells was markedly suppressed following BPI overexpression (p < 0.01). BPI overexpression had no significant effect on the mRNA-level expression of genes associated with glycosphingolipid biosynthesis or TLR4 signaling. BPI overexpression suppressed the LPS-induced TLR4 signaling pathway-related expression of proinflammatory cytokines (IFN-α, IFN-β, MIP-1α, MIP-1β and IL-6). Overall, our study serves as an overview of the association between BPI and resistance to E. coli F18 at the cellular level, offering a framework for future investigations of the mechanisms whereby piglets are able to resist E. coli F18 infection.

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