scholarly journals Carbon starvation-induced lipoprotein Slp directs the synthesis of catalase and expression of OxyR regulator to protect against hydrogen peroxide stress in Escherichia coli

2018 ◽  
Author(s):  
Xiaoxia Li ◽  
Yuanhong Xie ◽  
Junhua Jin ◽  
Hui Liu ◽  
Xiuzhi Gao ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Antioxidant Enzymes ◽  
Mutant Strain ◽  
Carbon Starvation ◽  
E Coli ◽  
Unique Mapping ◽  
Peroxide Stress

AbstractEscherichia coli can induce a group of stress-response proteins, including carbon starvation-induced lipoprotein (Slp), which is an outer membrane lipoprotein expressed in response to stressful environments. In this paper, slp null mutantE. coli were constructed by insertion of the group II intron, and then the growth sensitivity of the slp mutant strain was measured under 0.6% (vol/vol) hydrogen peroxide. The changes in resistance to hydrogen peroxide stress were investigated by detecting antioxidant activity and gene expression in the slp mutant strain. The results showed that deletion of the slp gene increased the sensitivity of E. coli under 0.6% (vol/vol) hydrogen peroxide oxidative stress. Analysis of the unique mapping rates from the transcriptome libraries revealed that four of thirteen remarkably up/down-regulated genes in E. coli were involved in antioxidant enzymes after mutation of the slp gene. Mutation of the slp gene caused a significant increase in catalase activity, which contributed to an increase in glutathione peroxidase activity. The katG gene was activated by the OxyR regulator, which was activated directly by 0.6% (vol/vol) hydrogen peroxide, and HPI encoded by katG was induced against oxidative stress. Therefore, the carbon starvation-induced lipoprotein Slp regulates the expression of antioxidant enzymes and the transcriptional activator OxyR in response to the hydrogen peroxide environment, ensuring that cells are protected from hydrogen peroxide oxidative stress at the level of enzyme activity and gene expression.

scholarly journals Necessity of OxyR for the Hydrogen Peroxide Stress Response and Full Virulence in Ralstonia solanacearum

2011 ◽  
Vol 77 (18) ◽  
pp. 6426-6432 ◽  
Author(s):  
Zomary Flores-Cruz ◽  
Caitilyn Allen
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Hydrogen Peroxide ◽  
Stress Response ◽  
Mutant Strain ◽  
Ralstonia Solanacearum ◽  
Oxidative Stress Response ◽  
Ros Scavenging ◽  
Content Type ◽  
Peroxide Stress

ABSTRACTThe plant pathogenRalstonia solanacearum, which causes bacterial wilt disease, is exposed to reactive oxygen species (ROS) during tomato infection and expresses diverse oxidative stress response (OSR) genes during midstage disease on tomato. TheR. solanacearumgenome predicts that the bacterium produces multiple and redundant ROS-scavenging enzymes but only one known oxidative stress response regulator, OxyR. AnR. solanacearumoxyRmutant had no detectable catalase activity, did not grow in the presence of 250 μM hydrogen peroxide, and grew poorly in the oxidative environment of solid rich media. This phenotype was rescued by the addition of exogenous catalase, suggesting thatoxyRis essential for the hydrogen peroxide stress response. Unexpectedly, theoxyRmutant strain grew better than the wild type in the presence of the superoxide generator paraquat. Gene expression studies indicated thatkatE,kaG,ahpC1,grxC, andoxyRitself were each differentially expressed in theoxyRmutant background and in response to hydrogen peroxide, suggesting thatoxyRis necessary for hydrogen peroxide-inducible gene expression. Additional OSR genes were differentially regulated in response to hydrogen peroxide alone. The virulence of theoxyRmutant strain was significantly reduced in both tomato and tobacco host plants, demonstrating thatR. solanacearumis exposed to inhibitory concentrations of ROSin plantaand that OxyR-mediated responses to ROS during plant pathogenesis are important forR. solanacearumhost adaptation and virulence.

scholarly journals Cultivation at high osmotic pressure confers ubiquinone 8–independent protection of respiration on Escherichia coli

2019 ◽  
Vol 295 (4) ◽  
pp. 981-993 ◽  
Author(s):  
Laura Tempelhagen ◽  
Anita Ayer ◽  
Doreen E. Culham ◽  
Roland Stocker ◽  
Janet M. Wood
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Escherichia Coli ◽  
Electron Transfer ◽  
Oxygen Uptake ◽  
Osmotic Pressure ◽  
Respiratory Chain ◽  
Membrane Lipid ◽  
E Coli ◽  
Uptake Rates

Ubiquinone 8 (coenzyme Q8 or Q8) mediates electron transfer within the aerobic respiratory chain, mitigates oxidative stress, and contributes to gene expression in Escherichia coli. In addition, Q8 was proposed to confer bacterial osmotolerance by accumulating during growth at high osmotic pressure and altering membrane stability. The osmolyte trehalose and membrane lipid cardiolipin accumulate in E. coli cells cultivated at high osmotic pressure. Here, Q8 deficiency impaired E. coli growth at low osmotic pressure and rendered growth osmotically sensitive. The Q8 deficiency impeded cellular O2 uptake and also inhibited the activities of two proton symporters, the osmosensing transporter ProP and the lactose transporter LacY. Q8 supplementation decreased membrane fluidity in liposomes, but did not affect ProP activity in proteoliposomes, which is respiration-independent. Liposomes and proteoliposomes prepared with E. coli lipids were used for these experiments. Similar oxygen uptake rates were observed for bacteria cultivated at low and high osmotic pressures. In contrast, respiration was dramatically inhibited when bacteria grown at the same low osmotic pressure were shifted to high osmotic pressure. Thus, respiration was restored during prolonged growth of E. coli at high osmotic pressure. Of note, bacteria cultivated at low and high osmotic pressures had similar Q8 concentrations. The protection of respiration was neither diminished by cardiolipin deficiency nor conferred by trehalose overproduction during growth at low osmotic pressure, but rather might be achieved by Q8-independent respiratory chain remodeling. We conclude that osmotolerance is conferred through Q8-independent protection of respiration, not by altering physical properties of the membrane.

scholarly journals Proline Metabolism IncreaseskatGExpression and Oxidative Stress Resistance in Escherichia coli

2014 ◽  
Vol 197 (3) ◽  
pp. 431-440 ◽  
Author(s):  
Lu Zhang ◽  
James R. Alfano ◽  
Donald F. Becker
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Mutant Strain ◽  
Stress Resistance ◽  
Proline Metabolism ◽  
Wild Type ◽  
Content Type ◽  
Oxidative Stress Resistance ◽  
Proline Utilization

The oxidation ofl-proline to glutamate in Gram-negative bacteria is catalyzed by the proline utilization A (PutA) flavoenzyme, which contains proline dehydrogenase (PRODH) and Δ1-pyrroline-5-carboxylate (P5C) dehydrogenase domains in a single polypeptide. Previous studies have suggested that aside from providing energy, proline metabolism influences oxidative stress resistance in different organisms. To explore this potential role and the mechanism, we characterized the oxidative stress resistance of wild-type andputAmutant strains ofEscherichia coli. Initial stress assays revealed that theputAmutant strain was significantly more sensitive to oxidative stress than the parental wild-type strain. Expression of PutA in theputAmutant strain restored oxidative stress resistance, confirming that depletion of PutA was responsible for the oxidative stress phenotype. Treatment of wild-type cells with proline significantly increased hydroperoxidase I (encoded bykatG) expression and activity. Furthermore, the ΔkatGstrain failed to respond to proline, indicating a critical role for hydroperoxidase I in the mechanism of proline protection. The global regulator OxyR activates the expression ofkatGalong with several other genes involved in oxidative stress defense. In addition tokatG, proline increased the expression ofgrxA(glutaredoxin 1) andtrxC(thioredoxin 2) of the OxyR regulon, implicating OxyR in proline protection. Proline oxidative metabolism was shown to generate hydrogen peroxide, indicating that proline increases oxidative stress tolerance inE. colivia a preadaptive effect involving endogenous hydrogen peroxide production and enhanced catalase-peroxidase activity.

Further investigation of the mechanism of Vitreoscilla hemoglobin (VHb) protection from oxidative stress in Escherichia coli

Biologia ◽  
2011 ◽  
Vol 66 (5) ◽  
Author(s):  
Meltem Akbas ◽  
Tugrul Doruk ◽  
Serhat Ozdemir ◽  
Benjamin Stark
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Stationary Phase ◽  
Exponential Phase ◽  
Vitreoscilla Hemoglobin ◽  
Sod Activity ◽  
E Coli ◽  
Hydrogen Peroxide Treatment

AbstractIn Escherichia coli, Vitreoscilla hemoglobin (VHb) protects against oxidative stress, perhaps, in part, by oxidizing OxyR. Here this protection, specifically VHb-associated effects on superoxide dismutase (SOD) and catalase levels, was examined. Exponential or stationary phase cultures of SOD+ or SOD− E. coli strains with or without VHb and oxyR antisense were treated with 2 mM hydrogen peroxide without sublethal peroxide induction, and compared to untreated control cultures. The hydrogen peroxide treatment was toxic to both SOD+ and SOD− cells, but much more to SOD− cells; expression of VHb in SOD+ strains enhanced this toxicity. In contrast, the presence of VHb was generally associated in the SOD+ background with a modest increase in SOD activity that was not greatly affected by oxyR antisense or peroxide treatment. In both SOD+ and SOD− backgrounds, VHb was associated with higher catalase activity both in the presence and absence of peroxide. Contrary to its stimulatory effects in stationary phase, in exponential phase oxyR antisense generally decreased VHb levels.

scholarly journals Escherichia coli O157 : H7 glutamate- and arginine-dependent acid-resistance systems protect against oxidative stress during extreme acid challenge

Microbiology ◽  
2009 ◽  
Vol 155 (3) ◽  
pp. 805-812 ◽  
Author(s):  
Bradley L. Bearson ◽  
In Soo Lee ◽  
Thomas A. Casey
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Acid Stress ◽  
Acid Resistance ◽  
Dependent Manner ◽  
Bacterial Survival ◽  
E Coli ◽  
Stress Protection ◽  
Acid Challenge

Micro-organisms may simultaneously encounter multiple stresses in their environment. To investigate the protection that several known Escherichia coli O157 : H7 acid-resistance systems might provide against both oxidative and acid stress, the addition of diamide, a membrane-permeable thiol-specific oxidizing agent, or hydrogen peroxide were used concurrent with acid challenge at pH 2.5 to determine bacterial survival. The addition of either diamide or hydrogen peroxide decreased bacterial survival in a dose-dependent manner for E. coli O157 : H7 during challenge at pH 2.5 following overnight growth in LB MES pH 5.5 (acid-resistance system 1, AR1). In contrast, the presence of either glutamate or arginine during challenge provided significant protection against diamide- and hydrogen peroxide-induced oxidative stress during pH 2.5 acid challenge. Oxidative stress protection during acid challenge required gadC and adiA for the glutamate- (AR2) and arginine- (AR3) dependent acid-resistance systems, respectively. In addition, maximal protection against oxidative stress in the presence of glutamate required a low external pH (pH 2.5), since pH 5.5 did not protect. This study demonstrates that the glutamate- and arginine-dependent acid-resistance systems of E. coli O157 : H7 can simultaneously protect against oxidative stress during extreme acid challenge.

scholarly journals Gamma Interferon Production by Hepatic NK T Cells during Escherichia coli Infection Is Resistant to the Inhibitory Effects of Oxidative Stress

2003 ◽  
Vol 71 (5) ◽  
pp. 2468-2477 ◽  
Author(s):  
Guochi Zhang ◽  
Robert Dru Nichols ◽  
Masaru Taniguchi ◽  
Toshinori Nakayama ◽  
Michael J. Parmely
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Escherichia Coli ◽  
T Cells ◽  
Nk Cells ◽  
Inhibitory Effects ◽  
Gram Negative ◽  
E Coli ◽  
Nk T Cells ◽  
Ifn Γ

ABSTRACT The reductive-oxidative status of tissues regulates the expression of many inflammatory genes that are induced during gram-negative bacterial infections. The cytokine gamma interferon (IFN-γ) is a potent stimulus for host inflammatory gene expression, and oxidative stress has been shown to inhibit its production in mice challenged with Escherichia coli bacteria. The objective of the present study was to characterize the cells that produced IFN-γ in a mouse bacterial peritonitis model and determine the effects of oxidative stress on their activation. The liver contained large numbers of IFN-γ-expressing lymphocytes following challenge with viable E. coli bacteria. The surface phenotypes of IFN-γ-expressing hepatic lymphocytes were those of natural killer (NK) cells (NK1.1+ CD3−), conventional T cells (NK1.1− CD3+), and NK T cells (NK1.1+ CD3+). Treating mice with diethyl maleate to deplete tissue thiols significantly impaired IFN-γ production by NK cells, conventional T cells, and CD1d-restricted NK T cells in response to E. coli challenge. However, IFN-γ expression by a subset of NK T cells, which did not bind α-galactosylceramide-CD1d tetramers, was resistant to the inhibitory effects of tissue oxidative stress. Stress-resistant IFN-γ-expressing cells were also predominantly CD8+ and bore γδ T-cell antigen receptors. The residual IFN-γ response by NK T cells may explain previous reports of hepatic gene expression following gram-negative bacterial challenge in thiol-depleted mice. The finding also demonstrates that innate immune cells differ significantly in their responses to altered tissue redox status.

Hypersalinity and Hydrogen Peroxide Upregulation of Gene Expression of Antioxidant Enzymes in Ulva fasciata Against Oxidative Stress

2008 ◽  
Vol 11 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Ming-Shiuan Sung ◽  
Yi-Ting Hsu ◽  
Yuan-Ting Hsu ◽  
Tzure-Meng Wu ◽  
Tse-Min Lee
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Hydrogen Peroxide ◽  
Antioxidant Enzymes ◽  
Ulva Fasciata

scholarly journals Mechanisms of Copper Tolerance, Accumulation, and Detoxification in the Marine Macroalga Ulva compressa (Chlorophyta): 20 Years of Research

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 681
Author(s):  
Alejandra Moenne ◽  
Melissa Gómez ◽  
Daniel Laporte ◽  
Daniela Espinoza ◽  
Claudio A. Sáez ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Hydrogen Peroxide ◽  
Antioxidant Enzymes ◽  
Intracellular Calcium ◽  
Protein Kinases ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Ulva Compressa ◽  
Dependent Protein ◽  
Tolerance Accumulation

Copper induces an oxidative stress condition in the marine alga Ulva compressa that is due to the production of superoxide anions and hydrogen peroxide, mainly in organelles. The increase in hydrogen peroxide is accompanied by increases in intracellular calcium and nitric oxide, and there is a crosstalk among these signals. The increase in intracellular calcium activates signaling pathways involving Calmodulin-dependent Protein Kinases (CaMKs) and Calcium-Dependent Protein Kinases (CDPKs), leading to activation of gene expression of antioxidant enzymes and enzymes involved in ascorbate (ASC) and glutathione (GSH) synthesis. It was recently shown that copper also activates Mitogen-Activated Protein Kinases (MAPKs) that participate in the increase in the expression of antioxidant enzymes. The increase in gene expression leads to enhanced activities of antioxidant enzymes and to enhanced levels of ASC and GSH. In addition, copper induces an increase in photosynthesis leading to an increase in the leve of Nicotinamide Adenine Dinucleotide Phosphate (NADPH). Copper also induces an increase in activities of enzymes involved in C, N, and S assimilation, allowing the replacement of proteins damaged by oxidative stress. The accumulation of copper in acute exposure involved increases in GSH, phytochelatins (PCs), and metallothioneins (MTs) whereas the accumulation of copper in chronic exposure involved only MTs. Acute and chronic copper exposure induced the accumulation of copper-containing particles in chloroplasts. On the other hand, copper is extruded from the alga with an equimolar amount of GSH. Thus, the increases in activities of antioxidant enzymes, in ASC, GSH, and NADPH levels, and in C, N, and S assimilation, the accumulation of copper-containing particles in chloroplasts, and the extrusion of copper ions from the alga constitute essential mechanisms that participate in the buffering of copper-induced oxidative stress in U. compressa.

scholarly journals Coping with Reactive Oxygen Species to Ensure Genome Stability in Escherichia coli

Genes ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 565 ◽  
Author(s):  
Belén Mendoza-Chamizo ◽  
Anders Løbner-Olesen ◽  
Godefroid Charbon
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Cell Cycle ◽  
Hydrogen Peroxide ◽  
Reactive Oxygen ◽  
Single Strand ◽  
Aerobic Bacterium ◽  
Superoxide Anions ◽  
Strand Breaks ◽  
E Coli

The facultative aerobic bacterium Escherichia coli adjusts its cell cycle to environmental conditions. Because of its lifestyle, the bacterium has to balance the use of oxygen with the potential lethal effects of its poisonous derivatives. Oxidative damages perpetrated by molecules such as hydrogen peroxide and superoxide anions directly incapacitate metabolic activities relying on enzymes co-factored with iron and flavins. Consequently, growth is inhibited when the bacterium faces substantial reactive oxygen insults coming from environmental or cellular sources. Although hydrogen peroxide and superoxide anions do not oxidize DNA directly, these molecules feed directly or indirectly the generation of the highly reactive hydroxyl radical that damages the bacterial chromosome. Oxidized bases are normally excised and the single strand gap repaired by the base excision repair pathway (BER). This process is especially problematic in E. coli because replication forks do not sense the presence of damages or a stalled fork ahead of them. As consequence, single-strand breaks are turned into double-strand breaks (DSB) through replication. Since E. coli tolerates the presence of DSBs poorly, BER can become toxic during oxidative stress. Here we review the repair strategies that E. coli adopts to preserve genome integrity during oxidative stress and their relation to cell cycle control of DNA replication.

scholarly journals DNA Microarray-Mediated Transcriptional Profiling of the Escherichia coli Response to Hydrogen Peroxide

2001 ◽  
Vol 183 (15) ◽  
pp. 4562-4570 ◽  
Author(s):  
Ming Zheng ◽  
Xunde Wang ◽  
Lori J. Templeton ◽  
Dana R. Smulski ◽  
Robert A. LaRossa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Dna Microarray ◽  
Response Regulator ◽  
Transcriptional Profiling ◽  
Cluster Formation ◽  
Open Reading Frames ◽  
Cluster Assembly ◽  
E Coli

ABSTRACT The genome-wide transcription profile of Escherichia coli cells treated with hydrogen peroxide was examined with a DNA microarray composed of 4,169 E. coli open reading frames. By measuring gene expression in isogenic wild-type andoxyR deletion strains, we confirmed that the peroxide response regulator OxyR activates most of the highly hydrogen peroxide-inducible genes. The DNA microarray measurements allowed the identification of several new OxyR-activated genes, including thehemH heme biosynthetic gene; the six-genesuf operon, which may participate in Fe-S cluster assembly or repair; and four genes of unknown function. We also identified several genes, including uxuA, encoding mannonate hydrolase, whose expression might be repressed by OxyR, since their expression was elevated in the ΔoxyR mutant strain. In addition, the induction of some genes was found to be OxyR independent, indicating the existence of other peroxide sensors and regulators in E. coli. For example, theisc operon, which specifies Fe-S cluster formation and repair activities, was induced by hydrogen peroxide in strains lacking either OxyR or the superoxide response regulators SoxRS. These results expand our understanding of the oxidative stress response and raise interesting questions regarding the nature of other regulators that modulate gene expression in response to hydrogen peroxide.

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