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Reactive oxygen species bacteria

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https://www.readbyqxmd.com/read/28640632/gut-microbiota-nitric-oxide-and-microglia-as-pre-requisites-for-neurodegenerative-disorders
#1
Joyce Ka Yu 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...
June 22, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28634473/toxic-effects-of-prodigiosin-secreted-by-hahella-sp-ka22-on-harmful-alga-phaeocystis-globosa
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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
https://www.readbyqxmd.com/read/28595000/antimicrobial-gold-nanoclusters
#9
Kaiyuan Zheng, Magdiel I Setyawati, David Tai Leong, Jianping Xie
Bulk gold (Au) is known to be chemically inactive. However, when the size of Au nanoparticles (Au NPs) decreases to close to 1 nm or sub-nanometer dimensions, these ultrasmall Au nanoclusters (Au NCs) begin to possess interesting physical and chemical properties and likewise spawn different applications when working with bulk Au or even Au NPs. In this study, we found that it is possible to confer antimicrobial activity to Au NPs through precise control of their size down to NC dimension (typically less than 2 nm)...
June 13, 2017: ACS Nano
https://www.readbyqxmd.com/read/28593142/spontaneous-formation-of-neutrophil-extracellular-traps-in-serum-free-culture-conditions
#10
Go Kamoshida, Takane Kikuchi-Ueda, Satoshi Nishida, Shigeru Tansho-Nagakawa, Hirotoshi Kikuchi, Tsuneyuki Ubagai, Yasuo Ono
Neutrophils play a critical role in the innate immune response. Recently, a new neutrophilic biological defense mechanism, termed neutrophil extracellular traps (NETs), has been attracting attention. Neutrophils have been observed to release both lysosomal enzymes and their nuclear contents, including unfolded chromatin, which together trap and inactivate bacteria. The environment in tissues where neutrophils act is thought to be different from that of the blood serum. In this study, we assessed the effect of serum on NET formation...
June 2017: FEBS Open Bio
https://www.readbyqxmd.com/read/28592799/whib4-regulates-the-pe-ppe-gene-family-and-is-essential-for-virulence-of-mycobacterium-marinum
#11
Jing Wu, Huan-Wei Ru, Zhi-Hao Xiang, Jun Jiang, Yu-Chen Wang, Lu Zhang, Jun Liu
During the course of infection, pathogenic mycobacteria including Mycobacterium tuberculosis (M. tb) encounter host environments of variable oxygen tension, ranging from the hypoxic center of granulomas to the most oxygenated region in the lung cavities. Mycobacterial responses to changes of oxygen tension are critically related to infection outcomes, such as latency and reactivation. WhiB4 is an iron-sulfur containing transcription factor that is highly sensitive to oxygen exposure. In this study, we found that WhiB4 of Mycobacterium marinum (M...
June 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28587675/bactericidal-effects-of-310%C3%A2-nm-ultraviolet-light-emitting-diode-irradiation-on-oral-bacteria
#12
Ayuko Takada, Kenji Matsushita, Satoru Horioka, Yasushi Furuichi, Yasunori Sumi
BACKGROUND: Ultraviolet (UV) light is used for phototherapy in dermatology, and UVB light (around 310 nm) is effective for treatment of psoriasis and atopic dermatitis. In addition, it is known that UVC light (around 265 nm) has a bactericidal effect, but little is known about the bactericidal effect of UVB light. In this study, we examined the bactericidal effects of UVB-light emitting diode (LED) irradiation on oral bacteria to explore the possibility of using a 310 nm UVB-LED irradiation device for treatment of oral infectious diseases...
June 6, 2017: BMC Oral Health
https://www.readbyqxmd.com/read/28580180/the-role-of-reactive-oxygen-species-in-the-antimicrobial-activity-of-pyochelin
#13
Kuan Shion Ong, Yuen Lin Cheow, Sui Mae Lee
The increase in prevalence of antimicrobial-resistant bacteria (ARB) is currently a serious threat, thus there is a need for new antimicrobial compounds to combat infections caused by these ARB. An antimicrobial-producing bacterium, Burkholderia paludis was recently isolated and was able to produce a type of siderophore with antimicrobial properties, later identified as pyochelin. The chelating ability of pyochelin has been well-characterized but not for its antimicrobial characteristics. It was found that pyochelin had MIC values (MBC values) of 3...
July 2017: Journal of Advanced Research
https://www.readbyqxmd.com/read/28576061/in-vitro-efficacy-of-different-morphology-zinc-oxide-nanopowders-on-streptococcus-sobrinus-and-streptococcus-mutans
#14
Siti Khadijah Mohd Bakhori, Shahrom Mahmud, Chuo Ann Ling, Amna Hassan Sirelkhatim, Habsah Hasan, Dasmawati Mohamad, Sam'an Malik Masudi, Azman Seeni, Rosliza Abd Rahman
ZnO with two different morphologies were used to study the inhibition of Streptococcus sobrinus and Streptococcus mutans which are closely associated with tooth cavity. Rod-like shaped ZnO-A and plate-like shaped ZnO-B were produced using a zinc boiling furnace. The nanopowders were characterized using energy filtered transmission electron microscopy (EFTEM), X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, Raman spectroscopy and dynamic light scattering (DLS) to confirm the properties of the ZnO polycrystalline wurtzite structures...
September 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28574339/diverse-stimuli-engage-different-neutrophil-extracellular-trap-pathways
#15
Elaine F Kenny, Alf Herzig, Renate Krüger, Aaron Muth, Santanu Mondal, Paul R Thompson, Volker Brinkmann, Horst Von Bernuth, Arturo Zychlinsky
Neutrophils release neutrophil extracellular traps (NETs) which ensnare pathogens and have pathogenic functions in diverse diseases. We examined the NETosis pathways induced by five stimuli; PMA, the calcium ionophore A23187, nigericin, Candida albicans and Group B Streptococcus. We studied NET production in neutrophils from healthy donors with inhibitors of molecules crucial to PMA induced NETs including protein kinase C, calcium, reactive oxygen species, the enzymes myeloperoxidase (MPO) and neutrophil elastase...
June 2, 2017: ELife
https://www.readbyqxmd.com/read/28571818/association-between-oxidative-status-and-the-composition-of-intestinal-microbiota-along-the-gastrointestinal-tract
#16
Marianna Gyuraszova, Alexandra Kovalcikova, Roman Gardlik
Studies have shown that the microbiota along the gastrointestinal tract (GIT) plays an important role when it comes to the maintenance of its proper functions. Many studies exist that have analyzed the composition of the bacterial community in the different regions of the GIT of humans and model animals. Microbial imbalance leads to several systemic disorders, including cardiovascular and renal disease. The imbalance between the production of reactive oxygen species (ROS) and their elimination by antioxidants leads to oxidative stress...
June 2017: Medical Hypotheses
https://www.readbyqxmd.com/read/28567016/streptomyces-sp-mum212-as-a-source-of-antioxidants-with-radical-scavenging-and-metal-chelating-properties
#17
Loh Teng-Hern Tan, Kok-Gan Chan, Tahir Mehmood Khan, Sarah Ibrahim Bukhari, Surasak Saokaew, Acharaporn Duangjai, Priyia Pusparajah, Learn-Han Lee, Bey-Hing Goh
Reactive oxygen species and other radicals potentially cause oxidative damage to proteins, lipids, and DNA which may ultimately lead to various complications including mutations, carcinogenesis, neurodegeneration, cardiovascular disease, aging, and inflammatory disease. Recent reports demonstrate that Streptomyces bacteria produce metabolites with potent antioxidant activity that may be developed into therapeutic drugs to combat oxidative stress. This study shows that Streptomyces sp. MUM212 which was isolated from mangrove soil in Kuala Selangor, Malaysia, could be a potential source of antioxidants...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/28565928/iron-oxide-magnetic-nanoparticles-as-antimicrobials-for-therapeutics
#18
Lucas de Alcântara Sica de Toledo, Hélen Cássia Rosseto, Marcos Luciano Bruschi
The use of iron oxide magnetic nanoparticles (IMNP) in medical and pharmaceutical areas dates to the beginning of the 1970s, as carriers. Some other uses to these nanoparticles are in vitro separation, magnetic resonance imaging and drug targeting agent. Many preparations containing IMNP have been described and used in drug delivery, hyperthermia, in vitro separation, tissue repair, cellular therapy, for magnetic separation, magnetic resonance imaging, as spoilers for magnetic resonance spectroscopy, and more recently as sensors for metabolites and other biomolecules...
June 21, 2017: Pharmaceutical Development and Technology
https://www.readbyqxmd.com/read/28557543/impaired-mitochondrial-microbicidal-responses-in-chronic-obstructive-pulmonary-disease-macrophages
#19
Martin A Bewley, Julie A Preston, Mohammed Mohasin, Helen M Marriott, Richard C Budd, Julie Swales, Paul Collini, David R Greaves, Ruth W Craig, Christopher E Brightling, Louise E Donnelly, Peter J Barnes, Dave Singh, Steven D Shapiro, Moira K B Whyte, David H Dockrell
RATIONALE: Chronic obstructive pulmonary disease (COPD) is characterized by impaired clearance of pulmonary bacteria. OBJECTIVES: The effect of COPD on alveolar macrophage (AM) microbicidal responses was investigated. METHODS: Alveolar macrophages (AMs) were obtained from bronchoalveolar lavage from healthy donors or COPD patients and challenged with opsonized serotype 14 Streptococcus pneumoniae. Cells were assessed for apoptosis, bactericidal activity and mitochondrial reactive oxygen species (mROS) production...
May 30, 2017: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/28554073/facile-synthesis-of-heterostructured-cerium-oxide-yttrium-oxide-nanocomposite-in-uv-light-induced-photocatalytic-degradation-and-catalytic-reduction-synergistic-effect-of-antimicrobial-studies
#20
C Maria Magdalane, K Kaviyarasu, J Judith Vijaya, B Siddhardha, B Jeyaraj
Ceria (CeO2) is an exciting alternative noble metal catalyst, because it has ability to release and absorb oxygen in the redox system, and function as an oxygen buffer. In this study, heterostructured catalysts consisting of CeO2/Y2O3 nanocomposites were successfully synthesized by hydrothermal method in the presence of sodium hydroxide as a reducing agent from cerium nitrate and yttrium nitrate as a precursor which was then evaluated for its photocatalytic activity in the degradation of Rhodamine B (RhB) synthetic dye...
May 20, 2017: Journal of Photochemistry and Photobiology. B, Biology
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