scholarly journals Oxidative Stress Correlates with Wolbachia-Mediated Antiviral Protection in Wolbachia-Drosophila Associations

2015 ◽  
Vol 81 (9) ◽  
pp. 3001-3005 ◽  
Author(s):  
Zhee Sheen Wong ◽  
Jeremy C. Brownlie ◽  
Karyn N. Johnson
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Biocontrol Agent ◽  
Oxygen Species ◽  
Content Type ◽  
Host Insect ◽  
Fitness Traits ◽  
Endogenous Reactive Oxygen Species ◽  
Potential Biocontrol Agent ◽  
Definition Of

ABSTRACTWolbachiamediates antiviral protection in insect hosts and is being developed as a potential biocontrol agent to reduce the spread of insect-vectored viruses. Definition of the molecular mechanism that generates protection is important for understanding the tripartite interaction between host insect,Wolbachia, and virus. Elevated oxidative stress was previously reported for a mosquito line experimentally infected withWolbachia, suggesting that oxidative stress is important forWolbachia-mediated antiviral protection. However,Wolbachiaexperimentally introduced into mosquitoes impacts a range of host fitness traits, some of which are unrelated to antiviral protection. To explore whether elevated oxidative stress is associated with antiviral protection inWolbachia-infected insects, we analyzed oxidative stress of fiveWolbachia-infectedDrosophilalines. In flies infected with protectiveWolbachiastrains, hydrogen peroxide concentrations were 1.25- to 2-fold higher than those in paired fly lines cured ofWolbachiainfection. In contrast, there was no difference in the hydrogen peroxide concentrations in flies infected with nonprotectiveWolbachiastrains compared to flies cured ofWolbachiainfection. Using aDrosophilamutant that produces increased levels of hydrogen peroxide, we investigated whether flies with high levels of endogenous reactive oxygen species had altered responses to virus infection and found that flies with high levels of endogenous hydrogen peroxide were less susceptible to virus-induced mortality. Taken together, these results suggest that elevated oxidative stress correlates withWolbachia-mediated antiviral protection in naturalDrosophilahosts.

scholarly journals Intracellular Sources of ROS/H2O2 in Health and Neurodegeneration: Spotlight on Endoplasmic Reticulum

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 233
Author(s):  
Tasuku Konno ◽  
Eduardo Pinho Melo ◽  
Joseph E. Chambers ◽  
Edward Avezov
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Endoplasmic Reticulum ◽  
Neurodegenerative Diseases ◽  
Antioxidative Enzymes ◽  
Redox Reactions ◽  
Ros Production ◽  
Oxygen Species ◽  
Specific Target

Reactive oxygen species (ROS) are produced continuously throughout the cell as products of various redox reactions. Yet these products function as important signal messengers, acting through oxidation of specific target factors. Whilst excess ROS production has the potential to induce oxidative stress, physiological roles of ROS are supported by a spatiotemporal equilibrium between ROS producers and scavengers such as antioxidative enzymes. In the endoplasmic reticulum (ER), hydrogen peroxide (H2O2), a non-radical ROS, is produced through the process of oxidative folding. Utilisation and dysregulation of H2O2, in particular that generated in the ER, affects not only cellular homeostasis but also the longevity of organisms. ROS dysregulation has been implicated in various pathologies including dementia and other neurodegenerative diseases, sanctioning a field of research that strives to better understand cell-intrinsic ROS production. Here we review the organelle-specific ROS-generating and consuming pathways, providing evidence that the ER is a major contributing source of potentially pathologic ROS.

scholarly journals Novel Antioxidant Properties of Doxycycline

2018 ◽  
Vol 19 (12) ◽  
pp. 4078 ◽  
Author(s):  
Dahn Clemens ◽  
Michael Duryee ◽  
Cleofes Sarmiento ◽  
Andrew Chiou ◽  
Jacob McGowan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Chronic Inflammation ◽  
Antioxidant Properties ◽  
Antibacterial Properties ◽  
Reactive Oxygen ◽  
Protein Adducts ◽  
Oxygen Species ◽  
Free System

Doxycycline (DOX), a derivative of tetracycline, is a broad-spectrum antibiotic that exhibits a number of therapeutic activities in addition to its antibacterial properties. For example, DOX has been used in the management of a number of diseases characterized by chronic inflammation. One potential mechanism by which DOX inhibits the progression of these diseases is by reducing oxidative stress, thereby inhibiting subsequent lipid peroxidation and inflammatory responses. Herein, we tested the hypothesis that DOX directly scavenges reactive oxygen species (ROS) and inhibits the formation of redox-mediated malondialdehyde-acetaldehyde (MAA) protein adducts. Using a cell-free system, we demonstrated that DOX scavenged reactive oxygen species (ROS) produced during the formation of MAA-adducts and inhibits the formation of MAA-protein adducts. To determine whether DOX scavenges specific ROS, we examined the ability of DOX to directly scavenge superoxide and hydrogen peroxide. Using electron paramagnetic resonance (EPR) spectroscopy, we found that DOX directly scavenged superoxide, but not hydrogen peroxide. Additionally, we found that DOX inhibits MAA-induced activation of Nrf2, a redox-sensitive transcription factor. Together, these findings demonstrate the under-recognized direct antioxidant property of DOX that may help to explain its therapeutic potential in the treatment of conditions characterized by chronic inflammation and increased oxidative stress.

scholarly journals Oxidative Stressors Modify the Response of Streptococcus mutans to Its Competence Signal Peptides

2017 ◽  
Vol 83 (22) ◽  
Author(s):  
Matthew De Furio ◽  
Sang Joon Ahn ◽  
Robert A. Burne ◽  
Stephen J. Hagen
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Dental Caries ◽  
Signaling Pathway ◽  
Streptococcus Mutans ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Oral Biofilm ◽  
Genetic Competence ◽  
Content Type

ABSTRACTThe dental caries pathogenStreptococcus mutansis continually exposed to several types of stress in the oral biofilm environment. Oxidative stress generated by reactive oxygen species has a major impact on the establishment, persistence, and virulence ofS. mutans. Here, we combined fluorescent reporter-promoter fusions with single-cell imaging to study the effects of reactive oxygen species on activation of genetic competence inS. mutans. Exposure to paraquat, which generates superoxide anion, produced a qualitatively different effect on activation of expression of the gene for the master competence regulator, ComX, than did treatment with hydrogen peroxide (H2O2), which can yield hydroxyl radical. Paraquat suppressed peptide-mediated induction ofcomXin a progressive and cumulative fashion, whereas the response to H2O2displayed a strong threshold behavior. Low concentrations of H2O2had little effect on induction ofcomXor the bacteriocin genecipB, but expression of these genes declined sharply if extracellular H2O2exceeded a threshold concentration. These effects were not due to decreased reporter gene fluorescence. Two different threshold concentrations were observed in the response to H2O2, depending on the gene promoter that was analyzed and the pathway by which the competence regulon was stimulated. The results show that paraquat and H2O2affect theS. mutanscompetence signaling pathway differently, and that some portions of the competence signaling pathway are more sensitive to oxidative stress than others.IMPORTANCEStreptococcus mutansinhabits the oral biofilm, where it plays an important role in the development of dental caries. Environmental stresses such as oxidative stress influence the growth ofS. mutansand its important virulence-associated behaviors, such as genetic competence.S. mutanscompetence development is a complex behavior that involves two different signaling peptides and can exhibit cell-to-cell heterogeneity. Although oxidative stress is known to influenceS. mutanscompetence, it is not understood how oxidative stress interacts with the peptide signaling or affects heterogeneity. In this study, we used fluorescent reporters to probe the effect of reactive oxygen species on competence signaling at the single-cell level. Our data show that different reactive oxygen species have different effects onS. mutanscompetence, and that some portions of the signaling pathway are more acutely sensitive to oxidative stress than others.

scholarly journals Caffeic Acid - Potential Antioxidant in Cultured Human Retinal Pigment Epithelial Cells

1970 ◽  
Vol 66 (2) ◽  
Author(s):  
Dumitriţa RUGINǍ ◽  
Adela PINTEA ◽  
Raluca PÂRLOG ◽  
Andreea VARGA
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Protective Effect ◽  
Caffeic Acid ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Antioxidant Defence ◽  
Rpe Cells ◽  
In Cells

Oxidative stress causes biological changes responsible for carcinogenesis and aging in human cells. The retinal pigmented epithelium is continuously exposed to oxidative stress. Therefore reactive oxygen species (ROS) and products of lipid peroxidation accumulate in RPE. Neutralization of ROS occurs in retina by the action of antioxidant defence systems. In the present study, the protective effect of caffeic acid (3,4-dihydroxy cinnamic acid), a dietary phenolic compound, has been examined in normal and in oxidative stress conditions (500 µM peroxide oxygen) in cultures human epithelial pigment retinal cells (Nowak, M. et al.). The cell viability, the antioxidant enzymes activity (CAT, GPx, SOD) and the level of intracellular reactive oxygen species (ROS) were determined. Exposure to l00 µM caffeic acid for 24 h induced cellular changes indicating the protective effect of caffeic acid in RPE cells. Caffeic acid did not show any cytotoxic effect at concentrations lower than 200 μM in culture medium. Treatment of RPE cells with caffeic acid causes an increase of catalase, glutathione peroxidase and superoxide dismutase activity, especially in cells treated with hydrogen peroxide. Caffeic acid causes a decrease of ROS level in cells treated with hydrogen peroxide. This study proved that caffeic acid or food that contain high levels of this phenolic acid may have beneficial effects in prevention of retinal diseases associated with oxidative stress by improving antioxidant defence systems.

scholarly journals SodA Contributes to the Virulence of Avian PathogenicEscherichia coliO2 Strain E058 in Experimentally Infected Chickens

2019 ◽  
Vol 201 (6) ◽  
Author(s):  
Qingqing Gao ◽  
Le Xia ◽  
Xiaobo Wang ◽  
Zhengqin Ye ◽  
Jinbiao Liu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Virulence Factor ◽  
Infection Process ◽  
Strain Identification ◽  
Bacterial Disease ◽  
Wild Type ◽  
Content Type

ABSTRACTStrains of avian pathogenicEscherichia coli(APEC), the common pathogen of avian colibacillosis, encounter reactive oxygen species (ROS) during the infection process. Superoxide dismutases (SODs), acting as antioxidant factors, can protect against ROS-mediated host defenses. Our previous reports showed that thesodAgene (encoding a Mn-cofactor-containing SOD [MnSOD]) is highly expressed during the septicemic infection process of APEC.sodAhas been proven to be a virulence factor of certain pathogens, but its role in the pathogenicity of APEC has not been fully identified. In this study, we deleted thesodAgene from the virulent APEC O2 strain E058 and examined thein vitroandin vivophenotypes of the mutant. ThesodAmutant was more sensitive to hydrogen peroxide in terms of both its growth and viability than was the wild type. The ability to form a biofilm was weakened in thesodAmutant. ThesodAmutant was significantly more easily phagocytosed by chicken macrophages than was the wild-type strain. Chicken infection assays revealed significantly attenuated virulence of thesodAmutant compared with the wild type at 24 h postinfection. The virulence phenotype was restored by complementation of thesodAgene. Quantitative real-time reverse transcription-PCR revealed that the inactivation ofsodAreduced the expression of oxidative stress response geneskatE,perR, andosmCbut did not affect the expression ofsodBandsodC. Taken together, our studies indicate that SodA is important for oxidative resistance and virulence of APEC E058.IMPORTANCEAvian colibacillosis, caused by strains of avian pathogenicEscherichia coli, is a major bacterial disease of severe economic significance to the poultry industry worldwide. The virulence mechanisms of APEC are not completely understood. This study investigated the influence of an antioxidant protein, SodA, on the phenotype and pathogenicity of APEC O2 strain E058. This is the first report demonstrating that SodA plays an important role in protecting a specific APEC strain against hydrogen peroxide-induced oxidative stress and contributes to the virulence of this pathotype strain. Identification of this virulence factor will enhance our knowledge of APEC pathogenic mechanisms, which is crucial for designing successful strategies against associated infections and transmission.

scholarly journals Complete Genome Sequence of Ralstonia solanacearum FJAT-1458, a Potential Biocontrol Agent for Tomato Wilt

2017 ◽  
Vol 5 (14) ◽  
Author(s):  
Deju Chen ◽  
Bo Liu ◽  
Yujing Zhu ◽  
Jieping Wang ◽  
Zheng Chen ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Complete Genome Sequence ◽  
Biocontrol Agent ◽  
Avirulent Strain ◽  
Potential Candidate ◽  
Content Type ◽  
Potential Biocontrol Agent ◽  
Plant Vaccine

ABSTRACT An avirulent strain of Ralstonia solanacearum FJAT-1458 was isolated from a living tomato. Here, we report the complete R. solanacearum FJAT-1458 genome sequence of 6,059,899 bp and 5,241 genes. This bacterial strain is a potential candidate as a biocontrol agent in the form of a plant vaccine for bacterial wilt.

scholarly journals Arginine Biosynthesis Modulates Pyoverdine Production and Release in Pseudomonas putida as Part of the Mechanism of Adaptation to Oxidative Stress

2019 ◽  
Vol 201 (22) ◽  
Author(s):  
Laura Barrientos-Moreno ◽  
María Antonia Molina-Henares ◽  
Marta Pastor-García ◽  
María Isabel Ramos-González ◽  
Manuel Espinosa-Urgel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Pseudomonas Putida ◽  
Reactive Oxygen ◽  
Full Detail ◽  
Oxygen Species ◽  
Arginine Biosynthesis ◽  
Content Type ◽  
And Oxidative Stress

ABSTRACT Iron is essential for most life forms. Under iron-limiting conditions, many bacteria produce and release siderophores—molecules with high affinity for iron—which are then transported into the cell in their iron-bound form, allowing incorporation of the metal into a wide range of cellular processes. However, free iron can also be a source of reactive oxygen species that cause DNA, protein, and lipid damage. Not surprisingly, iron capture is finely regulated and linked to oxidative-stress responses. Here, we provide evidence indicating that in the plant-beneficial bacterium Pseudomonas putida KT2440, the amino acid l-arginine is a metabolic connector between iron capture and oxidative stress. Mutants defective in arginine biosynthesis show reduced production and release of the siderophore pyoverdine and altered expression of certain pyoverdine-related genes, resulting in higher sensitivity to iron limitation. Although the amino acid is not part of the siderophore side chain, addition of exogenous l-arginine restores pyoverdine release in the mutants, and increased pyoverdine production is observed in the presence of polyamines (agmatine and spermidine), of which arginine is a precursor. Spermidine also has a protective role against hydrogen peroxide in P. putida, whereas defects in arginine and pyoverdine synthesis result in increased production of reactive oxygen species. IMPORTANCE The results of this study show a previously unidentified connection between arginine metabolism, siderophore turnover, and oxidative stress in Pseudomonas putida. Although the precise molecular mechanisms involved have yet to be characterized in full detail, our data are consistent with a model in which arginine biosynthesis and the derived pathway leading to polyamine production function as a homeostasis mechanism that helps maintain the balance between iron uptake and oxidative-stress response systems.

scholarly journals Draft Genome Sequence of Pseudomonas fluorescens Strain TR3, a Potential Biocontrol Agent against the Rice Blast Fungus Magnaporthe oryzae

2017 ◽  
Vol 5 (47) ◽  
Author(s):  
Xue Zhang ◽  
Jin-Rong Xu ◽  
Cindy H. Nakatsu
Keyword(s):  
Pseudomonas Fluorescens ◽  
Genome Sequence ◽  
Magnaporthe Oryzae ◽  
Biocontrol Agent ◽  
Draft Genome ◽  
Rice Blast Fungus ◽  
Draft Genome Sequence ◽  
Content Type ◽  
Potential Biocontrol Agent ◽  
Rice Leaves

ABSTRACT We present the draft genome sequence of the potential biocontrol agent Pseudomonas fluorescens TR3, which was isolated from rice leaves infected with Magnaporthe oryzae in a greenhouse. The genome of TR3 was assembled into 26 scaffolds (~6 Mbp) and includes genes potentially involved in bacterial interactions with fungi.

scholarly journals In Vivo Fitness Adaptations of Colistin-Resistant Acinetobacter baumannii Isolates to Oxidative Stress

2016 ◽  
Vol 61 (3) ◽  
Author(s):  
Crystal L. Jones ◽  
Shweta S. Singh ◽  
Yonas Alamneh ◽  
Leila G. Casella ◽  
Robert K. Ernst ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Acinetobacter Baumannii ◽  
Catalase Activity ◽  
Content Type ◽  
Increased Susceptibility

ABSTRACT The loss of fitness in colistin-resistant (CR) Acinetobacter baumannii was investigated using longitudinal isolates from the same patient. Early CR isolates were outcompeted by late CR isolates for growth in broth and survival in the lungs of mice. Fitness loss was associated with an increased susceptibility to oxidative stress since early CR strains had reduced in vitro survival in the presence of hydrogen peroxide and decreased catalase activity compared to that of late CR and colistin-susceptible (CS) strains.

scholarly journals Complete Genome Sequence of Bacillus subtilis J-5, a Potential Biocontrol Agent

2017 ◽  
Vol 5 (23) ◽  
Author(s):  
Zhenhua Jia ◽  
Weiwei Jin ◽  
Yali Huang ◽  
Shuishan Song
Keyword(s):  
Bacillus Subtilis ◽  
Biocontrol Agent ◽  
Rhizosphere Soil ◽  
Whole Genome ◽  
Antimicrobial Compounds ◽  
Content Type ◽  
Regulatory Systems ◽  
Potential Biocontrol Agent ◽  
Genes Encoding ◽  
Shed Light

ABSTRACT Bacillus subtilis J-5 was isolated from tomato rhizosphere soil and exhibited strong inhibitory activity against Botrytis cinerea. To shed light on the molecular mechanism underlying the biological control on phytopathogens, the whole genome of this strain was sequenced. Genes encoding antimicrobial compounds and the regulatory systems were identified in the genome.

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