scholarly journals Glutathione Reductase Encoding Gene (gor) is Associated with Oxidative Stress and Antibiotic Susceptibility in Pseudomonas aeruginosa

2021 ◽  
pp. 1-8
Author(s):  
Ammar Abualnoor ◽  
Dong H. Kwon
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Pseudomonas Aeruginosa ◽  
Glutathione Reductase ◽  
Mutant Strain ◽  
Parental Strain ◽  
Antibiotic Susceptibility ◽  
Intrinsic Resistance ◽  
Bacterial Killing ◽  
Encoding Gene

Pseudomonas aeruginosa is a major causative agent of the hospital- and community-acquired infections. These infections are often antibiotic resistant and difficult to treat. Several intrinsic and acquired resistance mechanisms to antibiotics have reported in P. aeruginosa. Recently, oxidative- stress-scavenging-systems have suggested as a possible intrinsic resistance mechanism to antibiotics because oxidative stresses induced by bactericidal antibiotics contribute to bacterial killing effects. However, this remains controversial such that further clarification is required. Glutathione reductase is a key enzyme in the maintenance of the optimum level of intracellular glutathione-redox potential to ensure normal functioning of cellular processes including the detoxification of oxidative stress. In this study, the role of a glutathione-reductase-encoding gene (gor) in oxidative stress and antibiotic susceptibility was determined in P. aeruginosa. Results showed that a gor-mutant strain was more susceptible to hydrogen peroxide (but not superoxide) than the parental strain and 100% of cells were killed with 0.01% hydrogen peroxide while the parental strain survived at the same concentration of hydrogen peroxide. The gor-mutant strain was also more susceptible to carbenicillin, chloramphenicol, ciprofloxacin, and tetracycline than the parental strain, which was confirmed by bacterial killing-kinetics. These results suggest that the gor gene is associated with oxidative stress and susceptibility to bactericidal as well as bacteriostatic antibiotics and that the oxidative-stress-scavenging-systems may be a possible drug-target for multidrug resistant P. aeruginosa.

scholarly journals Decreased Antibiotic Susceptibility in Pseudomonas aeruginosa Surviving UV Irradition

2021 ◽  
Vol 12 ◽  
Author(s):  
Hai-bei Li ◽  
Ai-ming Hou ◽  
Tian-jiao Chen ◽  
Dong Yang ◽  
Zheng-shan Chen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Uv Irradiation ◽  
Antibiotic Susceptibility ◽  
Antibiotic Resistance Genes ◽  
Polymyxin B ◽  
Uv Exposure ◽  
Uv Disinfection ◽  
Excellent Performance

Given its excellent performance against the pathogens, UV disinfection has been applied broadly in different fields. However, only limited studies have comprehensively investigated the response of bacteria surviving UV irradiation to the environmental antibiotic stress. Here, we investigated the antibiotic susceptibility of Pseudomonas aeruginosa suffering from the UV irradiation. Our results revealed that UV exposure may decrease the susceptibility to tetracycline, ciprofloxacin, and polymyxin B in the survival P. aeruginosa. Mechanistically, UV exposure causes oxidative stress in P. aeruginosa and consequently induces dysregulation of genes contributed to the related antibiotic resistance genes. These results revealed that the insufficient ultraviolet radiation dose may result in the decreased antibiotic susceptibility in the pathogens, thus posing potential threats to the environment and human health.

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.

scholarly journals Contribution of Mn-Cofactored Superoxide Dismutase (SodA) to the Virulence of Streptococcus agalactiae

2001 ◽  
Vol 69 (8) ◽  
pp. 5098-5106 ◽  
Author(s):  
Claire Poyart ◽  
Elisabeth Pellegrini ◽  
Olivier Gaillot ◽  
Claire Boumaila ◽  
Marina Baptista ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Streptococcus Agalactiae ◽  
Specific Activity ◽  
Infection Model ◽  
Mouse Bone Marrow ◽  
Group B Streptococci ◽  
Bacterial Killing ◽  
Cell Extracts

ABSTRACT Superoxide dismutases convert superoxide anions to molecular oxygen and hydrogen peroxide, which, in turn, is metabolized by catalases and/or peroxidases. These enzymes constitute one of the major defense mechanisms of cells against oxidative stress and hence play a role in the pathogenesis of certain bacteria. We previously demonstrated that group B streptococci (GBS) possess a single Mn-cofactored superoxide dismutase (SodA). To analyze the role of this enzyme in the pathogenicity of GBS, we constructed a sodA-disrupted mutant of Streptococcus agalactiae NEM316 by allelic exchange. This mutant was subsequently cis complemented by integration into the chromosome of pAT113/Sp harboring the wild-typesodA gene. The SOD specific activity detected by gel analysis in cell extracts confirmed that active SODs were present in the parental and complemented strains but absent in thesodA mutant. The growth rates of these strains in standing cultures were comparable, but the sodA mutant was extremely susceptible to the oxidative stress generated by addition of paraquat or hydrogen peroxide to the culture medium and exhibited a higher mutation frequency in the presence of rifampin. In mouse bone marrow-derived macrophages, the sodA mutant showed an increased susceptibility to bacterial killing by macrophages. In a mouse infection model, after intravenous injection the survival of thesodA mutant in the blood and the brain was markedly reduced in comparison to that of the parental and complemented strains whereas only minor effects on survival in the liver and the spleen were observed. These results suggest that SodA plays a role in GBS pathogenesis.

Oxidative stress and antioxidant enzymes in triticale shoots under chloride salinization

2020 ◽  
Vol 63 (7) ◽  
pp. 99-105
Author(s):  
Viktor V. Ivanishchev ◽  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Lipid Peroxidation ◽  
Cluster Analysis ◽  
Antioxidant Enzymes ◽  
Glutathione Reductase ◽  
Guaiacol Peroxidase ◽  
Short Term ◽  
Stress Indicators ◽  
Oxidative Stress Indicators

We studied alterations in oxidative stress indicators (hydrogen peroxide, superoxide radical, lipid peroxidation – LPO) and alterations in the activity of antioxidant enzymes (catalase, ascorbate peroxidase, guaiacol peroxidase, glutathione reductase) in triticale shoots (Triticosecale) during short-term (0-96 h) sodium chloride stress (120 mM) with statistical methods: principal component analysis (PCA) and cluster analysis. Analysis of alterations in the activity of enzymes with the PCA method does not allow them to be unambiguously included in a single group, despite the fact that they all belong to antioxidant enzymes. The inclusion of oxidative stress indicators in this analysis did not make the picture simpler. Using the cluster analysis method, it can be concluded that under conditions of short-term chloride stress in the shoots of triticale, much more catalase (than other enzymes studied) is associated with the protection of membranes from lipid peroxidation than with the utilization of hydrogen peroxide. This is also reflected by the highest correlation coefficients: catalase – LPO (0.94), catalase – hydrogen peroxide (0.79). The formation of primary clusters between ascorbate peroxidase and glutathione reductase reflect the significance of the association of the ascorbate – glutathione cycle with the processes of utilization of reactive oxygen species (primarily hydrogen peroxide) under experimental conditions. It was also shown that under conditions of short-term chloride stress in the shoots of triticale, guaiacol peroxidase plays the least role in the utilization of hydrogen peroxide. In this case, salt ions again form a single primary cluster, which combines with other clusters at the maximum Euclidean distance in the experiment.

scholarly journals Global Analysis of Cellular Factors and Responses Involved in Pseudomonas aeruginosa Resistance to Arsenite

2005 ◽  
Vol 187 (14) ◽  
pp. 4853-4864 ◽  
Author(s):  
Kislay Parvatiyar ◽  
Eyad M. Alsabbagh ◽  
Urs A. Ochsner ◽  
Michelle A. Stegemeyer ◽  
Alan G. Smulian ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pseudomonas Aeruginosa ◽  
Glutathione Reductase ◽  
Type Strain ◽  
Wild Type Strain ◽  
Storage Proteins ◽  
Global Analysis ◽  
Wild Type ◽  
Isogenic Mutants ◽  
The Impact

ABSTRACT The impact of arsenite [As(III)] on several levels of cellular metabolism and gene regulation was examined in Pseudomonas aeruginosa. P. aeruginosa isogenic mutants devoid of antioxidant enzymes or defective in various metabolic pathways, DNA repair systems, metal storage proteins, global regulators, or quorum sensing circuitry were examined for their sensitivity to As(III). Mutants lacking the As(III) translocator (ArsB), superoxide dismutase (SOD), catabolite repression control protein (Crc), or glutathione reductase (Gor) were more sensitive to As(III) than wild-type bacteria. The MICs of As(III) under aerobic conditions were 0.2, 0.3, 0.8, and 1.9 mM for arsB, sodA sodB, crc, and gor mutants, respectively, and were 1.5- to 13-fold less than the MIC for the wild-type strain. A two-dimensional gel/matrix-assisted laser desorption ionization-time of flight analysis of As(III)-treated wild-type bacteria showed significantly (>40-fold) increased levels of a heat shock protein (IbpA) and a putative allo-threonine aldolase (GlyI). Smaller increases (up to 3.1-fold) in expression were observed for acetyl-coenzyme A acetyltransferase (AtoB), a probable aldehyde dehydrogenase (KauB), ribosomal protein L25 (RplY), and the probable DNA-binding stress protein (PA0962). In contrast, decreased levels of a heme oxygenase (HemO/PigA) were found upon As(III) treatment. Isogenic mutants were successfully constructed for six of the eight genes encoding the aforementioned proteins. When treated with sublethal concentrations of As(III), each mutant revealed a marginal to significant lag period prior to resumption of apparent normal growth compared to that observed in the wild-type strain. Our results suggest that As(III) exposure results in an oxidative stress-like response in P. aeruginosa, although activities of classic oxidative stress enzymes are not increased. Instead, relief from As(III)-based oxidative stress is accomplished from the collective activities of ArsB, glutathione reductase, and the global regulator Crc. SOD appears to be involved, but its function may be in the protection of superoxide-sensitive sulfhydryl groups.

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 Genome-Wide Transcriptional Profiling of the Steady-State Response of Pseudomonas aeruginosa to Hydrogen Peroxide

2005 ◽  
Vol 187 (8) ◽  
pp. 2565-2572 ◽  
Author(s):  
Prabhakar Salunkhe ◽  
Tanja Töpfer ◽  
Jan Buer ◽  
Burkhard Tümmler
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Pseudomonas Aeruginosa ◽  
Steady State ◽  
Expression Profiles ◽  
Transcriptome Profiling ◽  
Nitrate Respiration ◽  
Transcriptional Level ◽  
Steady State Response ◽  
State Response

ABSTRACT The steady-state response of Pseudomonas aeruginosa to the oxidative-stress-generating agent hydrogen peroxide was analyzed by PAO1 transcriptome profiling. In total, 694, 411, and 237 genes were upregulated and 668, 576, and 468 genes were downregulated in P. aeruginosa strains TB, 892, and PAO1, respectively. The expression profiles of the two variants of the TB clone were significantly more related to each other than the expression profile of either strain was to that of PAO1. Exposure to H2O2 activated by more than 10-fold the expression of the cyoABCD operon, which is key for aerobic respiration, and of oxidative-stress response elements such as the catalase KatB, the alkyl hydroperoxide reductase AhpF, and the thioredoxin reductase 2 operon. Genes for iron and sulfur homeostasis were upregulated. Most enzymes necessary for the conversion of amino acids into the citric acid cycle were globally downregulated at the transcriptional level. Nitrate respiration and arginine fermentation were shut off in the clone TB strains and attenuated in the PAO strain. The transcriptional profiles indicate that the two clone TB strains are more proficient in coping with H2O2-mediated oxidative stress than the reference strain PAO. According to this data, we recommend study of the transcriptome of strain PAO1 in parallel with those of at least two strains of another clone in order to differentiate common responses from clone- and strain-specific responses and to minimize overinterpretations of microarray data.

scholarly journals Role of Porphyromonas gingivalis FeoB2 in Metal Uptake and Oxidative Stress Protection

2006 ◽  
Vol 74 (7) ◽  
pp. 4214-4223 ◽  
Author(s):  
Jia He ◽  
Hiroshi Miyazaki ◽  
Cecilia Anaya ◽  
Fan Yu ◽  
W. Andrew Yeudall ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mutant Strain ◽  
Parental Strain ◽  
Atmospheric Oxygen ◽  
Host Cells ◽  
Deficient Mutant ◽  
Wild Type ◽  
Stress Protection ◽  
Oxidative Stress Protection

ABSTRACT Porphyromonas gingivalis, a gram-negative anaerobic bacterium, is a recognized periodontopathogen. It exhibits a high degree of aerotolerance and is able to survive in host cells, indicating that efficient oxidative stress protection mechanisms must be present in this organism. Manganese homeostasis plays a major role in oxidative stress protection in a variety of organisms; however, the transport and role of this metal in P. gingivalis is not well understood. Analysis of the genome of P. gingivalis W83 revealed the presence of two genes encoding homologs of a ferrous iron transport protein, FeoB1 and FeoB2. FeoB2 has been implicated in manganese accumulation in P. gingivalis. We sought to determine the role of the FeoB2 protein in metal transport as well as its contribution to resistance to oxygen radicals. Quantitative reverse transcriptase PCR analyses demonstrated that expression of feoB2 is induced in the presence of oxygen. The role of FeoB2 was investigated using an isogenic mutant strain deficient in the putative transporter. We characterized the FeoB2-mediated metal transport using 55Fe2+ and 54Mn2+. The FeoB2-deficient mutant had dramatically reduced rates of manganese uptake (0.028 pmol/min/107 bacteria) compared with the parental strain (0.33 pmol/min/107 bacteria) (after 20 min of uptake using 50 nM of 54Mn2+). The iron uptake rates, however, were higher in the mutant strain (0.75 pmol/min/107 bacteria) than in the wild type (0.39 pmol/min/107 bacteria). Interestingly, reduced survival rates were also noted for the mutant strain after exposure to H2O2 and to atmospheric oxygen compared to the parental strain cultured under the same conditions. In addition, in vitro infection of host cells with the wild type, the FeoB2-deficient mutant, and the same-site revertant revealed that the mutant had a significantly decreased capability for intracellular survival in the host cells compared to the wild-type strain. Our results demonstrate that feoB2 encodes a major manganese transporter required for protection of the bacterium from oxidative stress generated by atmospheric oxygen and H2O2. Furthermore, we show that FeoB2 and acquisition of manganese are required for intracellular survival of P. gingivalis in host cells.

scholarly journals Indicators of the antioxidant system and oxidative stress of triticale shoots under chloride salinity

2020 ◽  
Vol 63 (9) ◽  
pp. 51-58
Author(s):  
Viktor V. Ivanishchev ◽  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Cluster Analysis ◽  
Glutathione Reductase ◽  
Ascorbate Peroxidase ◽  
Correlation Coefficients ◽  
Low Molecular Weight ◽  
Guaiacol Peroxidase ◽  
Short Term

Alterations in the activity of antioxidant enzymes (catalase, ascorbate peroxidase, guaiacol peroxidase, glutathione reductase), the content of low molecular weight antioxidants (ascorbic acid, glutathione, and proline), as well as indicators of oxidative stress (hydrogen peroxide, superoxide radical, lipid peroxidation –LPO) in the shoots of triticale (Triticosecale) under short-term (0-96 h) sodium chloride stress (120 mM) were studied with statistical methods: principal component analysis (PCA) and cluster analysis. The application of the PCA method did not always lead to definite results that could be unambiguously interpreted from the point of view of modern concepts in the field of plant physiology and biochemistry. At the same time, high values of the correlation coefficients between individual indicators did not at all reflect their biochemical interdependence. The results obtained allow us to conclude that, under conditions of short-term chloride stress in triticale shoots, the more important function of proline is associated, rather, with the maintenance of osmotic pressure inside the cell than with the role of a low-molecular antioxidant. The mutual positive values of the correlation coefficients (with respect to each other) of the activity of catalase, glutathione reductase, LPO, the content of hydrogen peroxide and superoxide indicate the unidirectionality of the detected alterations, which reflect their known biochemical relationship and the need for glutathione reductase to maintain a certain redox-state in plant cells. With cluster analysis it was shown that under conditions of short-term chloride stress in triticale shoots, the studied enzymes (catalase, ascorbate peroxidase, guaiacol peroxidase, and glutathione reductase) play a more significant role in neutralizing of reactive oxygen species, and maintaining the state of membranes, than low molecular weight antioxidants.

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.

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