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Reactive oxygen species bacteria

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https://www.readbyqxmd.com/read/28335299/synthesis-of-sic-ag-cellulose-nanocomposite-and-its-antibacterial-activity-by-reactive-oxygen-species-generation
#1
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
#2
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
#3
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...
March 22, 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
#4
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
#5
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
https://www.readbyqxmd.com/read/28321528/silver-nanoparticles-against-salmonella-enterica-serotype-typhimurium-role-of-inner-membrane-dysfunction
#6
Minju Seong, Dong Gun Lee
The evolution of antibiotics-resistant bacteria is considered a major concern. To explore promising antibacterial materials and clarify their unknown mechanisms, the mode of action of silver nanoparticles (AgNPs) against Salmonella enterica serotype typhimurium was investigated. We investigated the effect of AgNPs on the bacterial membrane. The N-phenyl-1-naphthylamine assay showed that the permeability of the outer membrane was not changed by treatment with AgNPs. The O-nitrophenyl-β-D-galactopyranoside assay showed that the inner membrane permeability increased as AgNPs concentration increased...
March 21, 2017: Current Microbiology
https://www.readbyqxmd.com/read/28321410/oxidative-stress-induced-by-polymyxin-e-is-involved-in-rapid-killing-of-paenibacillus-polymyxa
#7
Zhiliang Yu, Yuyi Zhu, Wangrong Qin, Jianhua Yin, Juanping Qiu
Historically, the colistin has been thought to kill bacteria through membrane lysis. Here, we present an alternative mechanism that colistin induces rapid Paenibacillus polymyxa death through reactive oxygen species production. This significantly augments our understanding of the mechanism of colistin action, which is critical knowledge toward the yield development of colistin in the future.
2017: BioMed Research International
https://www.readbyqxmd.com/read/28319867/phototherapeutic-spectrum-expansion-through-synergistic-effect-of-mesoporous-silica-trio-nanohybrids-against-antibiotic-resistant-gram-negative-bacterium
#8
Yaswanth Kuthati, Ranjith Kumar Kankala, Prabhakar Busa, Shi-Xiang Lin, Jin-Pei Deng, Chung-Yuan Mou, Chia-Hung Lee
The extensive impact of antibiotic resistance has led to the exploration of new anti-bacterial modalities. We designed copper impregnated mesoporous silica nanoparticles (Cu-MSN) with immobilizing silver nanoparticles (SNPs) to apply photodynamic inactivation (PDI) of antibiotic-resistant E. coli. SNPs were decorated over the Cu-MSN surfaces by coordination of silver ions on diamine-functionalized Cu-MSN and further reduced to silver nanoparticles with formalin. We demonstrate that silver is capable of sensitizing the gram-negative bacteria E...
March 7, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28314049/biological-evaluation-of-3-hydroxybenzyl-alcohol-an-extrolite-produced-by-aspergillus-nidulans-strain-kzr-132
#9
C Ganesh Kumar, Poornima Mongolla, Sujitha Pombala, Shiva Bandi, K Suresh Babu, Kallaganti Venkata Siva Ramakrishna
AIMS: The aim of the study was to purify and characterize a bioactive compound from Aspergillus nidulans strain KZR-132 and its biological evaluation. METHODS AND RESULTS: A bioactive extolite was purified from Aspergillus nidulans strain KZR-132, and its chemical structure was elucidated as 3-hydroxylbenzyl alcohol (3-HBA) based on (1) H and (13) C NMR, FT-IR and mass spectroscopic analysis. The antimicrobial efficacy of 3-HBA was established against Gram-positive, Gram-negative bacteria and different Candida strains...
March 17, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28300180/systems-level-understanding-of-ethanol-induced-stresses-and-adaptation-in-e-coli
#10
Huansheng Cao, Du Wei, Yuedong Yang, Yu Shang, Gaoyang Li, Yaoqi Zhou, Qin Ma, Ying Xu
Understanding ethanol-induced stresses and responses in biofuel-producing bacteria at systems level has significant implications in engineering more efficient biofuel producers. We present a computational study of transcriptomic and genomic data of both ethanol-stressed and ethanol-adapted E. coli cells with computationally predicated ethanol-binding proteins and experimentally identified ethanol tolerance genes. Our analysis suggests: (1) ethanol damages cell wall and membrane integrity, causing increased stresses, particularly reactive oxygen species, which damages DNA and reduces the O2 level; (2) decreased cross-membrane proton gradient from membrane damage, coupled with hypoxia, leads to reduced ATP production by aerobic respiration, driving cells to rely more on fatty acid oxidation, anaerobic respiration and fermentation for ATP production; (3) the reduced ATP generation results in substantially decreased synthesis of macromolecules; (4) ethanol can directly bind 213 proteins including transcription factors, altering their functions; (5) all these changes together induce multiple stress responses, reduced biosynthesis, cell viability and growth; and (6) ethanol-adapted E...
March 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28291380/beneficial-rhizobacterium-bacillus-amyloliquefaciens-sqr9-induces-plant-salt-tolerance-through-spermidine-production
#11
Lin Chen, Yunpeng Liu, Gengwei Wu, Nan Zhang, Qi-Rong Shen, Ruifu Zhang
The inoculation of plants with plant growth-promoting rhizobacterium (PGPR) has been an effective strategy for enhancing plant salt tolerance to diminish the loss of agricultural productivity caused by salt stress, but the signal transmitted from bacteria to the plant under salt stress is poorly understood. In this study, the salt tolerance of Arabidopsis thaliana and Zea mays was enhanced by inoculation with Bacillus amyloliquefaciens SQR9. Using dialysis bags with different molecular weight cutoffs, we sorted through the molecules secreted by SQR9 and found that spermidine is responsible for enhancing plant salt tolerance...
March 14, 2017: Molecular Plant-microbe Interactions: MPMI
https://www.readbyqxmd.com/read/28290363/volatile-and-non-volatile-semi-volatile-compounds-and-in-vitro-bioactive-properties-of-chilean-ulmo-eucryphia-cordifolia-cav-honey
#12
Francisca Acevedo, Paulina Torres, B Dave Oomah, Severino Matias de Alencar, Adna Prado Massarioli, Raquel Martín-Venegas, Vicenta Albarral-Ávila, César Burgos-Díaz, Ruth Ferrer, Mónica Rubilar
Ulmo honey originating from Eucryphia cordifolia tree, known locally in the Araucania region as the Ulmo tree is a natural product with valuable nutritional and medicinal qualities. It has been used in the Mapuche culture to treat infections. This study aimed to identify the volatile and non-volatile/semi-volatile compounds of Ulmo honey and elucidate its in vitro biological properties by evaluating its antioxidant, antibacterial, antiproliferative and hemolytic properties and cytotoxicity in Caco-2 cells. Headspace volatiles of Ulmo honey were isolated by solid-phase microextraction (SPME); non-volatiles/semi-volatiles were obtained by removing all saccharides with acidified water and the compounds were identified by GC/MS analysis...
April 2017: Food Research International
https://www.readbyqxmd.com/read/28289730/indirect-interspecies-regulation-transcriptional-and-physiological-responses-of-a-cyanobacterium-to-heterotrophic-partnership
#13
Hans C Bernstein, Ryan S McClure, Vera Thiel, Natalie C Sadler, Young-Mo Kim, William B Chrisler, Eric A Hill, Donald A Bryant, Margaret F Romine, Janet K Jansson, Jim K Fredrickson, Alexander S Beliaev
The mechanisms by which microbes interact in communities remain poorly understood. Here, we interrogated specific interactions between photoautotrophic and heterotrophic members of a model consortium to infer mechanisms that mediate metabolic coupling and acclimation to partnership. This binary consortium was composed of a cyanobacterium, Thermosynechococcus elongatus BP-1, which supported growth of an obligate aerobic heterotroph, Meiothermus ruber strain A, by providing organic carbon, O2, and reduced nitrogen...
March 2017: MSystems
https://www.readbyqxmd.com/read/28288542/the-role-of-the-saliva-antioxidant-barrier-to-reactive-oxygen-species-with-regard-to-caries-development
#14
A Jurczak, D Kościelniak, A Skalniak, M Papież, P Vyhouskaya, W Krzyściak
OBJECTIVES: The aim of this study was to evaluate the role of the antioxidant barrier in the saliva of children with caries, and its impact on the colonization of cariogenic bacteria. METHODS: This is a cross-sectional study of 81 children aged 1-5 years. Antioxidant levels and salivary bacterial profiles were measured. Patients were divided into two groups as follows: initial stage decay, termed non-cavitated (1-2 in International Caries Detection and Assessment System (ICDAS)), and extensive decay, termed cavitated lesions (5-6 in ICDAS)...
March 13, 2017: Redox Report: Communications in Free Radical Research
https://www.readbyqxmd.com/read/28288207/type-vi-secretion-system-contributes-to-enterohemorrhagic-escherichia-coli-virulence-by-secreting-catalase-against-host-reactive-oxygen-species-ros
#15
Baoshan Wan, Qiufen Zhang, Jinjing Ni, Shuxian Li, Donghua Wen, Jun Li, Haihan Xiao, Ping He, Hong-Yu Ou, Jing Tao, Qihui Teng, Jie Lu, Wenjuan Wu, Yu-Feng Yao
Enterohemorrhagic Escherichia coli (EHEC) is one major type of contagious and foodborne pathogens. The type VI secretion system (T6SS) has been shown to be involved in the bacterial pathogenicity and bacteria-bacteria competition. Here, we show that EHEC could secrete a novel effector KatN, a Mn-containing catalase, in a T6SS-dependent manner. Expression of katN is promoted by RpoS and OxyR and repressed by H-NS, and katN contributes to bacterial growth under oxidative stress in vitro. KatN could be secreted into host cell cytosol after EHEC is phagocytized by macrophage, which leads to decreased level of intracellular reactive oxygen species (ROS) and facilitates the intramacrophage survival of EHEC...
March 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28281200/zntr-positively-regulates-t6ss4-expression-in-yersinia-pseudotuberculosis
#16
Tietao Wang, Keqi Chen, Fen Gao, Yiwen Kang, Muhammad Tausif Chaudhry, Zhuo Wang, Yao Wang, Xihui Shen
The type VI secretion system (T6SS) is a widespread and versatile protein secretion system found in most Gramnegative bacteria. Studies of T6SS have mainly focused on its role in virulence toward host cells and inter-bacterial interactions, but studies have also shown that T6SS4 in Yersinia pseudotuberculosis participates in the acquisition of zinc ions to alleviate the accumulation of hydroxyl radicals induced by multiple stressors. Here, by comparing the gene expression patterns of wild-type and zntR mutant Y...
March 10, 2017: Journal of Microbiology / the Microbiological Society of Korea
https://www.readbyqxmd.com/read/28276697/the-crosstalk-between-sphingomyelinases-and-reactive-oxygen-species-in-mycobacterial-infection
#17
Yuqing Wu, Erich Gulbins, Heike Grassme
SIGNIFICANCE: Tuberculosis (TB), which is caused by Mycobacterium tuberculosis, is one of the most important infections worldwide. The sphingomyelinase/ceramide system, which has been shown to be a crucial factor in internalizing and killing various pathogens, modulates both the pro-inflammatory response and the state of mycobacteria in macrophages. However, studies about the role of sphingomyelinases in TB are still at an early stage. Recent Advances: Recent studies elucidated several roles of sphingomyelinases in manipulating mycobacterial infections...
March 9, 2017: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/28272303/effects-of-silver-nanoparticles-on-multiple-drug-resistant-strains-of-staphylococcus-aureus-and-pseudomonas-aeruginosa-from-mastitis-infected-goats-an-alternative-approach-for-antimicrobial-therapy
#18
Yu-Guo Yuan, Qiu-Ling Peng, Sangiliyandi Gurunathan
Recently, silver nanoparticles (AgNPs) have been widely used in various applications as antimicrobial agents, anticancer, diagnostics, biomarkers, cell labels, and drug delivery systems for the treatment of various diseases. Microorganisms generally acquire resistance to antibiotics through the course of antibacterial therapy. Multi-drug resistance (MDR) has become a growing problem in the treatment of infectious diseases, and the widespread use of broad-spectrum antibiotics has resulted in the development of antibiotic resistance by numerous human and animal bacterial pathogens...
March 6, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28270505/essential-role-of-the-flexible-linker-on-the-conformational-equilibrium-of-bacterial-peroxiredoxin-reductase-for-effective-regeneration-of-peroxiredoxin
#19
Neelagandan Kamariah, Birgit Eisenhaber, Frank Eisenhaber, Gerhard Gruber
Reactive oxygen species (ROS) can damage DNA, proteins, and lipids, so cells have antioxidant systems that regulate ROS. In many bacteria, a dedicated peroxiredoxin reductase, alkyl hydroperoxide reductase subunit F (AhpF), catalyzes the rapid reduction of the redox-active disulfide center of the antioxidant protein peroxiredoxin (AhpC) to detoxify ROS such as hydrogen peroxide, organic hydroperoxide, and peroxynitrite. AhpF is a flexible multi-domain protein that enables a series of electron transfers among the redox centers by accepting reducing equivalents from NADH...
March 7, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28266207/synthesis-of-multifunctional-cationic-poly-p-phenylenevinylene-for-selectively-killing-bacteria-and-lysosome-specific-imaging
#20
Zhuo Chen, Huanxiang Yuan, Haiyan Liang
In this work, a cationic polymer was synthesized to bear quaternized N-methyl-imidazole groups in the side chains. Positively charged PPV-M could selectively bind to Gram-negative and Gram-positive bacteria over fungi and exhibit enhanced antibacterial activity with the aid of white light because PPV-M could sensitize oxygen to generate reactive oxygen species (ROS) that would damage bacteria. In addition, green fluorescent and positively charged PPV-M has the ability to enter mammalian cells and be specifically accumulated in lysosome...
March 22, 2017: ACS Applied Materials & Interfaces
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