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Reactive oxygen species bacteria

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https://www.readbyqxmd.com/read/28432145/bacterial-siderophores-hijack-neutrophil-functions
#1
Piu Saha, Beng San Yeoh, Rodrigo A Olvera, Xia Xiao, Vishal Singh, Deepika Awasthi, Bhagawat C Subramanian, Qiuyan Chen, Madhu Dikshit, Yanming Wang, Carole A Parent, Matam Vijay-Kumar
Neutrophils are the primary immune cells that respond to inflammation and combat microbial transgression. To thrive, the bacteria residing in their mammalian host have to withstand the antibactericidal responses of neutrophils. We report that enterobactin (Ent), a catecholate siderophore expressed by Escherichia coli, inhibited PMA-induced generation of reactive oxygen species (ROS) and neutrophil extracellular traps (NETs) in mouse and human neutrophils. Ent also impaired the degranulation of primary granules and inhibited phagocytosis and bactericidal activity of neutrophils, without affecting their migration and chemotaxis...
April 21, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28422486/stable-nanocomposite-based-on-pegylated-and-silver-nanoparticles-loaded-graphene-oxide-for-long-term-antibacterial-activity
#2
Rongtao Zhao, Min Lv, Yang Li, Mingxuan Sun, Wen Kong, Lihua Wang, Shiping Song, Chunhai Fan, Leili Jia, Shaofu Qiu, Yansong Sun, Hongbin Song, Rongzhang Hao
The increasing occurrence of antibiotic-resistant pathogens, especially superbugs, is compromising the efficacy of traditional antibiotics. Silver nanoparticles (AgNPs) loaded graphene oxide (GO) nanocomposite (GO-Ag) has drawn great interest as a promising alternative antibacterial material. However, GO-Ag nanocomposite often irreversibly aggregates in physiological solutions, severely influencing its antibacterial capacity and practical application. Herein, a PEGylated and AgNPs loaded GO nanocomposite (GO-PEG-Ag) is synthesized through a facile approach utilizing microwave irradiation, while avoiding extra reducing agents...
April 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28420885/oxidative-stress-protein-damage-and-repair-in-bacteria
#3
REVIEW
Benjamin Ezraty, Alexandra Gennaris, Frédéric Barras, Jean-François Collet
Oxidative damage can have a devastating effect on the structure and activity of proteins, and may even lead to cell death. The sulfur-containing amino acids cysteine and methionine are particularly susceptible to reactive oxygen species (ROS) and reactive chlorine species (RCS), which can damage proteins. In this Review, we discuss our current understanding of the reducing systems that enable bacteria to repair oxidatively damaged cysteine and methionine residues in the cytoplasm and in the bacterial cell envelope...
April 19, 2017: Nature Reviews. Microbiology
https://www.readbyqxmd.com/read/28408887/evaluation-of-salivary-and-serum-antioxidant-and-oxidative-stress-statuses-in-patients-with-chronic-periodontitis-a-case-control-study
#4
Fatemeh Ahmadi-Motamayel, Mohammad T Goodarzi, Zohreh Jamshidi, Reza Kebriaei
Aim: Local bacteria stimulate polymorphonuclear neutrophils to release reactive oxygen species in periodontitis. Increased levels of oxidative stress play a significant role in the pathogenesis of periodontitis. Therefore, this study aimed to evaluate total salivary and serum antioxidant capacity and malondialdehyde in patients with chronic periodontitis. Materials and methods: Fifty-five healthy subjects and 55 patients with chronic periodontitis, with an age range of 30-50 years, were evaluated. After clinical examination and case selection, unstimulated whole saliva was collected in the morning...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28387344/ph-controlled-cerium-oxide-nanoparticle-inhibition-of-both-gram-positive-and-gram-negative-bacteria-growth
#5
Ece Alpaslan, Benjamin M Geilich, Hilal Yazici, Thomas J Webster
Here, the antibacterial activity of dextran-coated nanoceria was examined against Pseudomonas aeruginosa and Staphylococcus epidermidis by varying the dose, the time of treatment, and the pH of the solution. Findings suggested that dextran-coated nanoceria particles were much more effective at killing P. aeruginosa and S. epidermidis at basic pH values (pH = 9) compared to acidic pH values (pH = 6) due to a smaller size and positive surface charge at pH 9. At pH 9, different particle concentrations did cause a delay in the growth of P...
April 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28382034/neutrophil-extracellular-traps-of-cynoglossus-semilaevis-production-characteristics-and-antibacterial-effect
#6
Ming-Li Zhao, Heng Chi, Li Sun
Neutrophil extracellular traps (NETs) are structures released by neutrophils as a cellular immune defense against microbial invasion. The process of NETs generation, netosis (NETosis), can take place via either a suicidal mechanism, during which the NETs-releasing cells became dead, or a "live" mechanism, during which the NETs-releasing cells remain vital. NETosis has been studied intensively in mammals in recent years, but very little is known about the NETosis in fish. In this study, we examined NETosis in tongue sole (Cynoglossus semilaevis), a species of teleost with important economic values...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28377755/production-of-superoxide-in-bacteria-is-stress-and-cell-state-dependent-a-gating-optimized-flow-cytometry-method-that-minimizes-ros-measurement-artifacts-with-fluorescent-dyes
#7
Megan E McBee, Yok H Chionh, Mariam L Sharaf, Peiying Ho, Maggie W L Cai, Peter C Dedon
The role of reactive oxygen species (ROS) in microbial metabolism and stress response has emerged as a major theme in microbiology and infectious disease. Reactive fluorescent dyes have the potential to advance the study of ROS in the complex intracellular environment, especially for high-content and high-throughput analyses. However, current dye-based approaches to measuring intracellular ROS have the potential for significant artifacts. Here, we describe a robust platform for flow cytometric quantification of ROS in bacteria using fluorescent dyes, with ROS measurements in 10s-of-1000s of individual cells under a variety of conditions...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28358809/oxidative-modification-and-electrochemical-inactivation-of-escherichia-coli-upon-cold-atmospheric-pressure-plasma-exposure
#8
Marlène Dezest, Anne-Laure Bulteau, Damien Quinton, Laurent Chavatte, Mickael Le Bechec, Jean Pierre Cambus, Stéphane Arbault, Anne Nègre-Salvayre, Franck Clément, Sarah Cousty
Cold atmospheric pressure plasmas (CAPPs) are known to have bactericidal effects but the mechanism of their interaction with microorganisms remains poorly understood. In this study the bacteria Escherichia coli were used as a model and were exposed to CAPPs. Different gas compositions, helium with or without adjunctions of nitrogen or oxygen, were used. Our results indicated that CAPP induced bacterial death at decontamination levels depend on the duration, post-treatment storage and the gas mixture composition used for the treatment...
2017: PloS One
https://www.readbyqxmd.com/read/28356348/tpl2-promotes-neutrophil-trafficking-oxidative-burst-and-bacterial-killing
#9
Nicole V Acuff, Xin Li, Jessica Elmore, Balázs Rada, Wendy T Watford
Tumor progression locus 2 (Tpl2) is a serine/threonine kinase that promotes inflammatory cytokine production by activating the MEK/ERK pathway. Tpl2 has been shown to be important for eliciting the inflammatory properties of macrophages; however, there is relatively little known about the contribution of Tpl2 to neutrophil effector functions. This is an important consideration, as neutrophils provide the first line of defense against infection in the innate immune system. We found that Tpl2 is expressed in both human and murine neutrophils, suggesting a potential function for Tpl2 in this lineage...
March 29, 2017: Journal of Leukocyte Biology
https://www.readbyqxmd.com/read/28352614/in-vivo-host-environment-alters-pseudomonas-aeruginosa-susceptibility-to-aminoglycoside-antibiotics
#10
Xiaolei Pan, Yuanyuan Dong, Zheng Fan, Chang Liu, Bin Xia, Jing Shi, Fang Bai, Yongxin Jin, Zhihui Cheng, Shouguang Jin, Weihui Wu
During host infection, Pseudomonas aeruginosa coordinately regulates the expression of numerous genes to adapt to the host environment while counteracting host clearance mechanisms. As infected patients take antibiotics, the invading bacteria encounter antibiotics in the host milieu. P. aeruginosa is highly resistant to antibiotics due to multiple chromosomally encoded resistant determinants. And numerous in vitro studies have demonstrated the regulatory mechanisms of antibiotic resistance related genes in response to antibiotics...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28349673/involvement-of-oxidative-stress-in-protocatechuic-acid-mediated-bacterial-lethality
#11
Taofeek O Ajiboye, Ramat S Habibu, Kabiru Saidu, Fatimah Z Haliru, Hikmat O Ajiboye, Najeeb O Aliyu, Oluwayemisi B Ibitoye, Judith N Uwazie, Hamdalat F Muritala, Sharafa A Bello, Idris I Yusuf, Aisha O Mohammed
The involvement of oxidative stress in protocatechuic acid-mediated bacterial lethality was investigated. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) of protocatechuic acid against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus are 600 and 700 μg/ml, 600 and 800 μg/ml, and 600 and 800 μg/ml, respectively. The optical densities and colony-forming units of protocatechuic acid-treated bacteria decreased in time-dependent manner. Protocatechuic acid (4× MIC) significantly increased the superoxide anion content of E...
March 27, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28347459/selenium-mediated-protection-in-reversing-the-sensitivity-of-bacterium-to-the-bactericidal-antibiotics
#12
Zhonglei Li, Jun Tan, Lei Shao, Xiaojing Dong, Richard D Ye, Daijie Chen
Inducing production of damaging reactive oxygen species (ROS) is an important criterion to distinguish the bactericidal antibiotics from bacteriostatic antibiotics. Selenoenzymes were generally recognized to be a powerful antioxidant capable of scavenging free radicals, protecting the cells from the harmful effects of ROS. Therefore, the present study was carried out to investigate the selenium (Se)-mediated protection in reversing antibiotic sensitivity and the role of selenoenzymes in alleviating the negative effects of oxidative stress...
May 2017: Journal of Trace Elements in Medicine and Biology
https://www.readbyqxmd.com/read/28345852/layer-number-dependent-antibacterial-and-osteogenic-behaviors-of-graphene-oxide-electrophoretic-deposited-on-titanium
#13
Jiajun Qiu, Hao Geng, Donghui Wang, Shi Qian, Hongqin Zhu, Yuqin Qiao, Wenhao Qian, Xuanyong Liu
Graphene oxide has attracted widespread attention in the biomedical fields due to its excellent biocompatibility. Herein we investigated the layer-number dependent antibacterial and osteogenic behaviors of graphene oxide in biointerfaces. Graphene oxide with different layer numbers was deposited on the titanium surfaces by cathodal electrophoretic deposition with varied deposition voltages. The initial cell adhesion and spreading, cell proliferation, and osteogenic differentiation were observed from all the samples using rat bone mesenchymal stem cells...
March 31, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28337206/cases-of-impaired-oxidative-burst-in-hiv-exposed-uninfected-infants-neutrophils-a-pilot-study
#14
Anicet Christel Maloupazoa Siawaya, Amandine Mveang-Nzoghe, Ofilia Mvoundza Ndjindji, Armel Mintsa Ndong, Paulin N Essone, Joel Fleury Djoba Siawaya
An increased risk of serious bacterial infections in HIV-exposed uninfected (HEU) infants has been demonstrated. Although neutrophils are essential for the protection of infants against bacterial infections, no study has investigated their profile in HEU infants to date. In this study, we assessed the function of neutrophils in HEU infants using the nitroblue tetrazolium reduction test. Among 25 HEU infants, 9 (36%) showed a reduced ability of their neutrophils to produce reactive oxygen species upon stimulation with bacteria...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28337204/phenol-soluble-modulin-%C3%AE-peptide-toxins-from-aggressive-staphylococcus-aureus-induce-rapid-formation-of-neutrophil-extracellular-traps-through-a-reactive-oxygen-species-independent-pathway
#15
Halla Björnsdottir, Agnes Dahlstrand Rudin, Felix P Klose, Jonas Elmwall, Amanda Welin, Marios Stylianou, Karin Christenson, Constantin F Urban, Huamei Forsman, Claes Dahlgren, Anna Karlsson, Johan Bylund
Neutrophils have the ability to capture and kill microbes extracellularly through the formation of neutrophil extracellular traps (NETs). These are DNA and protein structures that neutrophils release extracellularly and are believed to function as a defense mechanism against microbes. The classic NET formation process, triggered by, e.g., bacteria, fungi, or by direct stimulation of protein kinase C through phorbol myristate acetate, is an active process that takes several hours and relies on the production of reactive oxygen species (ROS) that are further modified by myeloperoxidase (MPO)...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28335299/synthesis-of-sic-ag-cellulose-nanocomposite-and-its-antibacterial-activity-by-reactive-oxygen-species-generation
#16
Andrzej Borkowski, Tomasz Cłapa, Mateusz Szala, Arkadiusz Gąsiński, Marek Selwet
We describe the synthesis of nanocomposites, based on nanofibers of silicon carbide, silver nanoparticles, and cellulose. Silver nanoparticle synthesis was achieved with chemical reduction using hydrazine by adding two different surfactants to obtain a nanocomposite with silver nanoparticles of different diameters. Determination of antibacterial activity was based on respiration tests. Enzymatic analysis indicates oxidative stress, and viability testing was conducted using an epifluorescence microscope. Strong bactericidal activity of nanocomposites was found against bacteria Escherichia coli and Bacillus cereus, which were used in the study as typical Gram-negative and Gram-positive bacteria, respectively...
September 13, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28333068/effects-of-reactive-oxygen-species-on-tubular-transport-along-the-nephron
#17
REVIEW
Agustin Gonzalez-Vicente, Jeffrey L Garvin
Reactive oxygen species (ROS) are oxygen-containing molecules naturally occurring in both inorganic and biological chemical systems. Due to their high reactivity and potentially damaging effects to biomolecules, cells express a battery of enzymes to rapidly metabolize them to innocuous intermediaries. Initially, ROS were considered by biologists as dangerous byproducts of respiration capable of causing oxidative stress, a condition in which overproduction of ROS leads to a reduction in protective molecules and enzymes and consequent damage to lipids, proteins, and DNA...
March 23, 2017: Antioxidants (Basel, Switzerland)
https://www.readbyqxmd.com/read/28330939/chlamydia-preserves-the-mitochondrial-network-necessary-for-replication-via-microrna-dependent-inhibition-of-fission
#18
Suvagata Roy Chowdhury, Anastasija Reimer, Malvika Sharan, Vera Kozjak-Pavlovic, Ana Eulalio, Bhupesh K Prusty, Martin Fraunholz, Karthika Karunakaran, Thomas Rudel
Obligate intracellular bacteria such as Chlamydia trachomatis depend on metabolites of the host cell and thus protect their sole replication niche by interfering with the host cells' stress response. Here, we investigated the involvement of host microRNAs (miRNAs) in maintaining the viability of C. trachomatis-infected primary human cells. We identified miR-30c-5p as a prominently up-regulated miRNA required for the stable down-regulation of p53, a major suppressor of metabolite supply in C. trachomatis-infected cells...
April 3, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28330248/photo-inactivation-of-escherichia-coli-and-enterococcus-hirae-using-methylene-blue-and-sodium-anthraquinone-2-sulphonate-effect-of-process-parameters
#19
Madhavi Singh, Kannan Pakshirajan, Vishal Trivedi
In this study, effect of different parameters, viz. concentration of photosensitizer (PS), pH of the bacterial cell suspension and initial cell count, on photo-inactivation of Escherichia coli and Enterococcus hirae bacteria using methylene blue (MB) and sodium anthraquinone-2-sulphonate (SAQS) was investigated employing the statistically valid full factorial design of experiments. The inactivation efficiency of E. hirae using MB ranges between 10.81 and 48.55 %, whereas in the case of E. coli it ranges between 10...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28322326/superoxide-dismutase-sod-1-modulates-c-elegans-pathogen-avoidance-behavior
#20
Alexander M Horspool, Howard C Chang
The C. elegans nervous system mediates protective physiological and behavioral responses amid infection. However, it remains largely unknown how the nervous system responds to reactive oxygen species (ROS) activated by pathogenic microbes during infection. Here, we show superoxide dismutase-1 (SOD-1), an enzyme that converts superoxide into less toxic hydrogen peroxide and oxygen, functions in the gustatory neuron ASER to mediate C. elegans pathogen avoidance response. When C. elegans first encounters pathogenic bacteria P...
March 21, 2017: Scientific Reports
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