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Reactive oxygen species bacteria

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https://www.readbyqxmd.com/read/28715739/antimicrobial-and-antibiofilm-efficacy-of-self-cleaning-surfaces-functionalized-by-tio2-photocatalytic-nanoparticles-against-staphylococcus-aureus-and-pseudomonas-putida
#1
Blanca Jalvo, Marisol Faraldos, Ana Bahamonde, Roberto Rosal
A photocatalytic sol of TiO2 nanoparticles has been used for creating self-cleaning antimicrobial flat and porous glass surfaces. The substrates were irradiated to study their photocatalytic properties and behavior in the presence of biofilm-forming bacteria. Smooth glass surfaces and glass microfiber filters were covered with 1.98×10(-3)±1.5×10(-4)gcm(-2) and 8.55×10(-3)±3.0×10(-4)gcm(-2) densities, respectively. Self-cleaning properties were analyzed using the methylene blue 365nm UV-A photodegradation test...
July 5, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28713774/epic-immune-battles-of-history-neutrophils-vs-staphylococcus-aureus
#2
REVIEW
Fermin E Guerra, Timothy R Borgogna, Delisha M Patel, Eli W Sward, Jovanka M Voyich
Neutrophils are the most abundant leukocytes in human blood and the first line of defense after bacteria have breached the epithelial barriers. After migration to a site of infection, neutrophils engage and expose invading microorganisms to antimicrobial peptides and proteins, as well as reactive oxygen species, as part of their bactericidal arsenal. Ideally, neutrophils ingest bacteria to prevent damage to surrounding cells and tissues, kill invading microorganisms with antimicrobial mechanisms, undergo programmed cell death to minimize inflammation, and are cleared away by macrophages...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28708374/chemical-modification-and-detoxification-of-the-pseudomonas-aeruginosa-toxin-2-heptyl-4-hydroxyquinoline-n-oxide-by-environmental-and-pathogenic-bacteria
#3
Sven Thierbach, Franziska S Birmes, Matthias C Letzel, Ulrich Hennecke, Susanne Fetzner
2-Heptyl-4-hydroxyquinoline N-oxide (HQNO), a major secondary metabolite and virulence factor produced by the opportunistic pathogen Pseudomonas aeruginosa, acts as potent inhibitor of respiratory electron transfer and thereby affects host cells as well as microorganisms. In this study, we demonstrate the previously unknown capability of environmental and pathogenic bacteria to transform and detoxify this compound. Strains of Arthrobacter and Rhodococcus spp. as well as Staphylococcus aureus introduced a hydroxyl group at C-3 of HQNO, whereas Mycobacterium abscessus, M...
July 14, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28708051/ralstonia-solanacearum-novel-e3-ubiquitin-ligase-nel-effectors-ripaw-and-ripar-suppress-pattern-triggered-immunity-in-plants
#4
Masahito Nakano, Kenji Oda, Takafumi Mukaihara
Ralstonia solanacearum is the causal agent of bacterial wilt in solanaceous crops. This pathogen injects more than 70 effector proteins into host plant cells via the Hrp type III secretion system to cause a successful infection. However, the function of these effectors in plant cells, especially in the suppression of plant immunity, remains largely unknown. In this study, we characterized two Ralstonia solanacearum effectors, RipAW and RipAR, which share homology with the IpaH family of effectors from animal and plant pathogenic bacteria, that have a novel E3 ubiquitin ligase (NEL) domain...
July 15, 2017: Microbiology
https://www.readbyqxmd.com/read/28703297/neither-eosinophils-nor-neutrophils-require-atg5-dependent-autophagy-for-extracellular-dna-trap-formation
#5
Nina Germic, Darko Stojkov, Kevin Oberson, Shida Yousefi, Hans-Uwe Simon
The importance of extracellular traps (ETs) in innate immunity is well established, but the molecular mechanisms responsible for their formation remain unclear and in scientific dispute. ETs have been defined as extracellular DNA scaffolds associated with the granule proteins of eosinophils or neutrophils. They are capable of killing bacteria extracellularly. Based mainly on results with phosphoinositide 3-kinase (PI3K) inhibitors such as 3-methyladenine (3-MA) and wortmannin which are commonly used to inhibit autophagy, several groups have reported that autophagy is required for neutrophil extracellular trap (NET) formation...
July 13, 2017: Immunology
https://www.readbyqxmd.com/read/28701733/endosomal-nox2-oxidase-exacerbates-virus-pathogenicity-and-is-a-target-for-antiviral-therapy
#6
Eunice E To, Ross Vlahos, Raymond Luong, Michelle L Halls, Patrick C Reading, Paul T King, Christopher Chan, Grant R Drummond, Christopher G Sobey, Brad R S Broughton, Malcolm R Starkey, Renee van der Sluis, Sharon R Lewin, Steven Bozinovski, Luke A J O'Neill, Tim Quach, Christopher J H Porter, Doug A Brooks, John J O'Leary, Stavros Selemidis
The imminent threat of viral epidemics and pandemics dictates a need for therapeutic approaches that target viral pathology irrespective of the infecting strain. Reactive oxygen species are ancient processes that protect plants, fungi and animals against invading pathogens including bacteria. However, in mammals reactive oxygen species production paradoxically promotes virus pathogenicity by mechanisms not yet defined. Here we identify that the primary enzymatic source of reactive oxygen species, NOX2 oxidase, is activated by single stranded RNA and DNA viruses in endocytic compartments resulting in endosomal hydrogen peroxide generation, which suppresses antiviral and humoral signaling networks via modification of a unique, highly conserved cysteine residue (Cys98) on Toll-like receptor-7...
July 12, 2017: Nature Communications
https://www.readbyqxmd.com/read/28699742/quantitative-analysis-of-reactive-oxygen-species-photo-generated-on-metal-oxide-nanoparticles-and-their-bacteria-toxicity-the-role-of-superoxide-radicals
#7
Dan Wang, Lixia Zhao, Haiyan Ma, Hui Zhang, Liang-Hong Guo
Ecotoxicity of engineered nanoparticles (NPs) have become the focus of considerable attention due to their wide applications. Reactive oxygen species (ROS) play important roles in the toxicity mechanisms of engineered metal-oxide NPs. This work aimed to understand quantitatively the contribution of photo-generated ROS on metal oxide NPs to their toxicity. The dynamic generation of O2•-, •OH and H2O2 in aqueous suspensions of photo-illuminated metal oxide nano- and bulk particles (TiO2, ZnO, V2O5, CeO2, Fe2O3, and Al2O3) was measured by a continuous-flow chemiluminescence (CFCL) detection system...
July 12, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28674938/herbaspirillum-rubrisubalbicans-a-mild-pathogen-impairs-growth-of-rice-by-augmenting-ethylene-levels
#8
Glaucio Valdameri, Dayane Alberton, Vivian Rotuno Moure, Thiago Borba Kokot, Caroline Kukolj, Liziane Cristina Campos Brusamarello-Santos, Rose Adele Monteiro, Fabio de Oliveira Pedrosa, Emanuel Maltempi de Souza
Herbaspirillum rubrisubalbicans decreases growth of rice. Inoculation of rice with H. rubrisubalbicans increased the ACCO mRNA levels and ethylene production. The H. rubrisubalbicans rice interactions were further characterized by proteomic approach. Herbaspirillum rubrisubalbicans is a well-known growth-promoting rhizobacteria that can also act as a mild phyto-pathogen. During colonisation of rice, RT-qPCR analyses showed that H. rubrisubalbicans up-regulates the methionine recycling pathway as well as phyto-siderophore synthesis genes...
July 3, 2017: Plant Molecular Biology
https://www.readbyqxmd.com/read/28671732/a-highly-efficient-and-photostable-photosensitizer-with-near-infrared-aggregation-induced-emission-for-image-guided-photodynamic-anticancer-therapy
#9
Wenbo Wu, Duo Mao, Fang Hu, Shidang Xu, Chao Chen, Chong-Jing Zhang, Xiamin Cheng, Youyong Yuan, Dan Ding, Deling Kong, Bin Liu
Photodynamic therapy (PDT), which relies on photosensitizers (PS) and light to generate reactive oxygen species to kill cancer cells or bacteria, has attracted much attention in recent years. PSs with both bright emission and efficient singlet oxygen generation have also been used for image-guided PDT. However, simultaneously achieving effective (1) O2 generation, long wavelength absorption, and stable near-infrared (NIR) emission with low dark toxicity in a single PS remains challenging. In addition, it is well known that when traditional PSs are made into nanoparticles, they encounter quenched fluorescence and reduced (1) O2 production...
July 3, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28656172/sulfide-homeostasis-and-nitroxyl-intersect-via-formation-of-reactive-sulfur-species-in-staphylococcus-aureus
#10
Hui Peng, Jiangchuan Shen, Katherine A Edmonds, Justin L Luebke, Anne K Hickey, Lauren D Palmer, Feng-Ming James Chang, Kevin A Bruce, Thomas E Kehl-Fie, Eric P Skaar, David P Giedroc
Staphylococcus aureus is a commensal human pathogen and a major cause of nosocomial infections. As gaseous signaling molecules, endogenous hydrogen sulfide (H2S) and nitric oxide (NO·) protect S. aureus from antibiotic stress synergistically, which we propose involves the intermediacy of nitroxyl (HNO). Here, we examine the effect of exogenous sulfide and HNO on the transcriptome and the formation of low-molecular-weight (LMW) thiol persulfides of bacillithiol, cysteine, and coenzyme A as representative of reactive sulfur species (RSS) in wild-type and ΔcstR strains of S...
May 2017: MSphere
https://www.readbyqxmd.com/read/28649409/bacillus-subtilis-utilizes-the-dna-damage-response-to-manage-multicellular-development
#11
Kevin Gozzi, Carly Ching, Srinand Paruthiyil, Yinjuan Zhao, Veronica Godoy-Carter, Yunrong Chai
Bacteria switch between free-living and a multicellular state, known as biofilms, in response to cellular and environmental cues. It is important to understand how these cues influence biofilm development as biofilms are not only ubiquitous in nature but are also causative agents of infectious diseases. It is often believed that any stress triggers biofilm formation as a means of bacterial protection. In this study, we propose a new mechanism for how cellular and environmental DNA damage may influence biofilm formation...
2017: NPJ Biofilms and Microbiomes
https://www.readbyqxmd.com/read/28649250/immunity-in-protochordates-the-tunicate-perspective
#12
REVIEW
Nicola Franchi, Loriano Ballarin
Tunicates are the closest relatives of vertebrates, and their peculiar phylogenetic position explains the increasing interest toward tunicate immunobiology. They are filter-feeding organisms, and this greatly influences their defense strategies. The majority of the studies on tunicate immunity were carried out in ascidians. The tunic acts as a first barrier against pathogens and parasites. In addition, the oral siphon and the pharynx represent two major, highly vascularized, immune organs, where circulating hemocytes can sense non-self material and trigger immune responses that, usually, lead to inflammation and phagocytosis...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28640632/gut-microbiota-nitric-oxide-and-microglia-as-prerequisites-for-neurodegenerative-disorders
#13
Joyce K Y Tse
Regulating fluctuating endogenous nitric oxide (NO) levels is necessary for proper physiological functions. Aberrant NO pathways are implicated in a number of neurological disorders, including Alzheimer's disease (AD) and Parkinson's disease. The mechanism of NO in oxidative and nitrosative stress with pathological consequences involves reactions with reactive oxygen species (e.g., superoxide) to form the highly reactive peroxynitrite, hydrogen peroxide, hypochloride ions and hydroxyl radical. NO levels are typically regulated by endogenous nitric oxide synthases (NOS), and inflammatory iNOS is implicated in the pathogenesis of neurodegenerative diseases, in which elevated NO mediates axonal degeneration and activates cyclooxygenases to provoke neuroinflammation...
July 7, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28634473/toxic-effects-of-prodigiosin-secreted-by-hahella-sp-ka22-on-harmful-alga-phaeocystis-globosa
#14
Huajun Zhang, Hui Wang, Wei Zheng, Zhiyuan Yao, Yun Peng, Su Zhang, Zhong Hu, Zhen Tao, Tianling Zheng
Application of algicidal compounds secreted by bacteria is a promising and environmentally friendly strategy to control harmful algal blooms (HABs). Years ago prodigiosin was described as an efficient algicidal compound, but the details about the effect of prodigiosin on algal cells are still elusive. Prodigiosin shows high algicidal activity on Phaeocystis globosa, making it a potential algicide in HAB control. When P. globosa were treated with prodigiosin at 5 μg/mL, algae cells showed cytoplasmic hypervacuolization, chloroplast and nucleus rupture, flagella missing, and cell fracture, when observed by scanning electron microscope and transmission electron microscopy...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28629723/microbial-antioxidant-defense-enzymes
#15
REVIEW
Cindy Staerck, Amandine Gastebois, Patrick Vandeputte, Alphonse Calenda, Gérald Larcher, Louiza Gillmann, Nicolas Papon, Jean-Philippe Bouchara, Maxime J J Fleury
Free radicals are often described as chemical compounds characterized by unpaired electrons in their outer orbital rendering them highly reactive species. In mammalians, studies on free radicals were focused on reactive oxygen species (ROS) or reactive nitrogen species (RNS) due to their relative importance in physiological as well as in pathological processes. These cellular compounds are produced by different physiological systems such as the aerobic metabolism and play a major role in cell signaling pathways but also in the host immune defenses against pathogenic microorganisms...
June 16, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28625994/a-small-protein-hemp-is-a-transcriptional-activator-for-hemin-uptake-operon-in-burkholderia-multivorans-atcc-17616
#16
Takuya Sato, Shouta Nonoyama, Akane Kimura, Yuji Nagata, Yoshiyuki Ohtsubo, Masataka Tsuda
Iron and heme play very important roles in various metabolic functions in bacteria, and their intracellular homeostasis is maintained because high concentrations of free forms of these molecules greatly facilitate the Fenton reaction-mediated production of large amounts of reactive oxygen species that severely damage various biomolecules. Ferric uptake regulator (Fur) from Burkholderiamultivorans ATCC 17616 is an iron-responsive global transcriptional regulator, and its fur deletant exhibits pleiotropic phenotypes...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28617616/the-role-of-nrf2-in-the-regulation-of-periodontal-health-and-disease
#17
A V Chiu, M Al Saigh, C A McCulloch, M Glogauer
Immune-related disease tolerance is an important defense strategy that facilitates the maintenance of health in organs and tissues that are commonly colonized by bacteria. Immune tolerance to dysbiotic, tooth-borne biofilms is a poorly understood yet clinically relevant concept in the immunopathological mechanisms that are involved in the pathogenesis of periodontitis, particularly those related to neutrophil and macrophage responses. In periodontal health, neutrophils and macrophages respond to the formation of pathogenic bacterial biofilms by the production of bactericidal reactive oxygen species (ROS)...
June 1, 2017: Journal of Dental Research
https://www.readbyqxmd.com/read/28611461/jnk-activation-turns-on-lps-and-gram-negative-bacteria-induced-nadph-oxidase-dependent-suicidal-netosis
#18
Meraj A Khan, Armin Farahvash, David N Douda, Johann-Christoph Licht, Hartmut Grasemann, Neil Sweezey, Nades Palaniyar
Neutrophils cast neutrophil extracellular traps (NETs) to ensnare microbial pathogens. Nevertheless, the molecular rheostats that regulate NETosis in response to bacteria are not clearly established. We hypothesized that stress-activated protein kinase or c-Jun N-terminal Kinase (SAPK/JNK) is a molecular switch that turns on NETosis in response to increasing concentrations of lipopolysaccharide (LPS)- and Gram-negative bacteria. Here we show that Escherichia coli LPS (0111:B4; 10-25 μg/ml), but not phorbol myristate acetate (PMA), activates JNK in human neutrophils in a dose-dependent manner...
June 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28609580/metabolic-defense-against-oxidative-stress-the-road-less-travelled-so-far
#19
REVIEW
Joe Lemire, Azhar Alhasawi, Varun P Appanna, Sujeenthar Tharmalingam, Vasu D Appanna
Bacteria have survived, and many have thrived, since antiquity in the presence of the highly-reactive chalcogen - oxygen (O2 ). They are known to evoke intricate strategies to defend themselves from the reactive by-products of oxygen - reactive oxygen species (ROS). Many of these detoxifying mechanisms have been extensively characterized; superoxide dismutase (SOD), catalases, alkyl hydroperoxide reductase and the glutathione (GSH)-cycling system are responsible for neutralizing specific ROS. Meanwhile, a pool of NADPH - the reductive engine of many ROS-combating enzymes - is maintained by metabolic enzymes including, but not exclusively, glucose-6 phosphate dehydrogenase (G6PDH) and NADP-dependent isocitrate dehydrogenase (ICDH-NADP)...
June 13, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28600938/highly-synergistic-antimicrobial-activity-of-spherical-and-flower-like-hierarchical-titanium-dioxide-silver-composites
#20
Junwei Ye, Hang Cheng, Hong Li, Yaoyao Yang, Siqi Zhang, Abdul Rauf, Qi Zhao, Guiling Ning
A spherical titanium dioxide/silver (TiO2/Ag) composite and a flower-like hierarchical TiO2/Ag composite were prepared via a template-induced method and a solvothermal method based on the Ag/Carbon spheres templates followed by calcination treatment, respectively. The morphologies of the composites were controlled by changing the concentration of reactants and calcination temperature. The antibacterial efficiency of the composites was evaluated with both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, respectively...
May 31, 2017: Journal of Colloid and Interface Science
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