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Reactive oxygen species bacteria

Yinglong Li, Jie Pan, Guopin Ye, Qian Zhang, Jing Wang, Jue Zhang, Jing Fang
The aim of this study was to evaluate the antimicrobial effects of non-thermal plasma-activated water (PAW) as a novel mouthwash in vitro. Three representative oral pathogens - Streptococcus mutans, Actinomyces viscosus and Porphyromonas gingivalis - were treated with PAW. The inactivation effect was evaluated using the colony-forming unit (CFU) method, and the morphological and structural changes of a cell were observed by scanning electron microscopy and transmission electron microscopy (TEM). The physicochemical properties of PAW were analysed, and its influence on the leakage of intracellular proteins and DNA was evaluated...
October 11, 2017: European Journal of Oral Sciences
Faria Fatima, Neelam Pathak, Smita Rastogi Verma, Preeti Bajpai
Silver myconanosomes prepared from Alternaria brassicae may exhibit potential antimicrobial and immunomodulatory activity due to their inimitable character. The prepared myconanosomes were characterized by using differential light scattering, zeta potential, UV-visible spectroscopy and transmission electron microscopic analyses. Mycologically produced AgNPs were found as spherical and irregular shaped measuring size range between 55.4 and 70.23 nm. The antimicrobicidal activity of these AgNPs against pathogenic microbes was evaluated by agar well diffusion method...
October 12, 2017: Artificial Cells, Nanomedicine, and Biotechnology
Chitrada Kaweeteerawat, Preeyawis Na Ubol, Sanirat Sangmuang, Sasitorn Aueviriyavit, Rawiwan Maniratanachote
Silver nanoparticles (AgNPs) are widely used in industry, consumer products, and medical appliances due to their efficient antimicrobial properties. However, information on environmental toxicity and bacterial impact of these particles is not completely elucidated. Results showed that AgNPs produced growth inhibition and oxidative stress in bacteria Escherichia coli (gram negative) and Staphylococcus aureus (gram positive), with half-maximal inhibitory concentrations (IC50) of 12 and 7 mg/L, respectively. Surprisingly, bacteria pre-exposed to sublethal dose of AgNPs exhibited increased resistance toward antibiotics (ampicillin and Pen-Strep) with IC50 elevated by 3-13-fold...
October 11, 2017: Journal of Toxicology and Environmental Health. Part A
Wook-Bin Lee, Ji-Jing Yan, Ji-Seon Kang, Lark Kyun Kim, Young-Joon Kim
Sepsis is a life-threatening condition caused by an uncontrolled response to bacterial infection. Impaired bactericidal activity in the host is directly associated with severe sepsis; however, the underlying regulatory mechanism(s) is largely unknown. Here, we show that MCL (macrophage C-type lectin) plays a crucial role in killing bacteria during Escherichia coli-induced peritonitis. MCL-deficient mice with E. coli-induced sepsis showed lower survival rates and reduced bacterial clearance when compared with control mice, despite similar levels of proinflammatory cytokine production...
October 5, 2017: Biochemical and Biophysical Research Communications
Liisa M Uotila, Carla Guenther, Terhi Savinko, Timo A Lehti, Susanna C Fagerholm
Neutrophils are of fundamental importance in the early immune response and use various mechanisms to neutralize invading pathogens. They kill endocytosed pathogens by releasing reactive oxygen species in the phagosome and release neutrophil extracellular traps (NETs) into their surroundings to immobilize and kill invading micro-organisms. Filamin A (FlnA) is an important actin cross-linking protein that is required for cellular processes involving actin rearrangements, such cell migration. It has also been shown to negatively regulate integrin activation and adhesion...
October 6, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
Colleen M Courtney, Samuel M Goodman, Toni A Nagy, Max Levy, Pallavi Bhusal, Nancy E Madinger, Corrella S Detweiler, Prashant Nagpal, Anushree Chatterjee
The rise of multidrug-resistant (MDR) bacteria is a growing concern to global health and is exacerbated by the lack of new antibiotics. To treat already pervasive MDR infections, new classes of antibiotics or antibiotic adjuvants are needed. Reactive oxygen species (ROS) have been shown to play a role during antibacterial action; however, it is not yet understood whether ROS contribute directly to or are an outcome of bacterial lethality caused by antibiotics. We show that a light-activated nanoparticle, designed to produce tunable flux of specific ROS, superoxide, potentiates the activity of antibiotics in clinical MDR isolates of Escherichia coli, Salmonella enterica, and Klebsiella pneumoniae...
October 2017: Science Advances
Rita Arabsolghar, Jamileh Saberzadeh, Forouzan Khodaei, Rozhin Abbasi Borojeni, Marjan Khorsand, Marzieh Rashedinia
Sodium benzoate (SB) is one of the food additives and preservatives that prevent the growth of fungi and bacteria. SB has been shown to improve the symptoms of neurodegenerative disease such as Alzheimer's disease. The aim of this study was to evaluate the effect of SB on the cell survival and cellular antioxidant indices after exposure to aluminum maltolate (Almal) in PC12 cell line as a model of neurotoxicity. The cells exposed to different concentrations of SB (0.125 to 3 mg/mL) in the presence of Almal (500 µM) and cell viability, the level of reactive oxygen species (ROS), glutathione content and catalase activity were measured...
October 2017: Research in Pharmaceutical Sciences
Yuzhi Hong, Liping Li, Gan Luan, Karl Drlica, Xilin Zhao
Nutrient starvation usually halts cell growth rather than causing death. Thymine starvation is exceptional, because it kills cells rapidly. This phenomenon, called thymineless death (TLD), underlies the action of several antibacterial, antimalarial, anticancer, and immunomodulatory agents. Many explanations for TLD have been advanced, with recent efforts focused on recombination proteins and replication origin (oriC) degradation. Because current proposals account for only part of TLD and because reactive oxygen species (ROS) are implicated in bacterial death due to other forms of harsh stress, we investigated the possible involvement of ROS in TLD...
October 2, 2017: Nature Microbiology
Cheng Lei, Yuqing Sun, Daniel C W Tsang, Daohui Lin
The increasing application of iron-based nanoparticles (NPs), especially high concentrations of zero-valent iron nanoparticles (nZVI), has raised concerns regarding their environmental behavior and potential ecological effects. In the environment, iron-based NPs undergo physical, chemical, and/or biological transformations as influenced by environmental factors such as pH, ions, dissolved oxygen, natural organic matter (NOM), and biotas. This review presents recent research advances on environmental transformations of iron-based NPs, and articulates their relationships with the observed toxicities...
September 28, 2017: Environmental Pollution
Saloumeh Ghasemian, Bahareh Asadishad, Sasha Omanovic, Nathalie Tufenkji
Electrochemical disinfection has been shown to be an efficient method with a shortrequired contact time for treatment of drinking water supplies, industrial raw water supplies, liquid foodstuffs, and wastewater effluents. In the present work, the electrochemical disinfection of saline water contaminated with bacteria was investigated in chloride-containing solutions using Sb-doped Sn80%-W20%-oxide anodes. The influence of current density, bacterial load, initial chloride concentration, solution pH, and the type of bacteria (E...
September 18, 2017: Water Research
Ebbe N Bak, Michael G Larsen, Ralf Moeller, Silas B Nissen, Lasse R Jensen, Per Nørnberg, Svend J K Jensen, Kai Finster
The habitability of Mars is determined by the physical and chemical environment. The effect of low water availability, temperature, low atmospheric pressure and strong UV radiation has been extensively studied in relation to the survival of microorganisms. In addition to these stress factors, it was recently found that silicates exposed to simulated saltation in a Mars-like atmosphere can lead to a production of reactive oxygen species. Here, we have investigated the stress effect induced by quartz and basalt abraded in Mars-like atmospheres by examining the survivability of the three microbial model organisms Pseudomonas putida, Bacillus subtilis, and Deinococcus radiodurans upon exposure to the abraded silicates...
2017: Frontiers in Microbiology
Kuriakose Jayesh, Lal Raisa Helen, A Vysakh, Eldhose Binil, M S Latha
Inflammation has been considered as a major risk factor for various kinds of human diseases. Macrophages play substantial roles in host defense against infection. It can be activated by lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria. The current study aims to investigate the anti-inflammatory effects of ethyl acetate fraction isolated from T. bellerica (EFTB) in LPS stimulated RAW 264.7 macrophage cell lines. The inhibitory effects of EFTB on total cyclooxygenase (COX), 5-lipoxygenase (5-LOX) activity, nitrate and inducible nitric oxide synthase (iNOS) level, reactive oxygen species (ROS) production were studied...
September 23, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Qiang Wu, Kailong Huang, Haohao Sun, Hongqiang Ren, Xu-Xiang Zhang, Lin Ye
To understand the effects of metal ions and nanoparticles (NPs) on nitrifying bacterial communities, this study investigates the impacts of zinc (Zn) NPs, zinc oxide (ZnO) NPs and Zn ions on the nitrifying bacterial communities. Under low Zn concentration (0.1mgL(-1)), the nitrification rate was promoted by Zn ions and inhibited by the two NPs, indicating that the toxicity of NPs was caused by the NPs themselves instead of the released Zn ions. Further analysis showed that both Zn NPs and ZnO NPs could result in substantial reactive oxygen species (ROS) production in the nitrifying bacteria community...
September 18, 2017: Journal of Hazardous Materials
Josefine Hirschfeld, Phillipa C White, Michael R Milward, Paul R Cooper, Iain L C Chapple
Background: Oral bacteria are the main trigger for the development of periodontitis and some species are known to modulate neutrophil function. This study aimed to explore the release of neutrophil extracellular traps (NETs), associated antimicrobial proteins and reactive oxygen species (ROS) in response to periodontal bacteria, as well as the underlying pathways.Methods: Isolated peripheral blood neutrophils were stimulated with 19 periodontal bacteria. NET and ROS release as well as the expression of NET-bound antimicrobial proteins, elastase, myeloperoxidase and cathepsin G, in response to these species were measured using fluorescence-based assays...
September 25, 2017: Infection and Immunity
Zhigang Li, Yang Jiao, Erica K Fan, Melanie J Scott, Yuehua Li, Song Li, Timothy R Billiar, Mark A Wilson, Xueyin Shi, Jie Fan
In elderly patients, bacterial infection often causes severe complications and sepsis. Compared to younger patients, older patients are more susceptible to sepsis caused by respiratory infection. Macrophage (Mϕ) phagocytosis of bacteria plays a critical role in the clearance of pathogens and the initiation of immune responses. It has been suggested that Mϕ exhibit age-related functional alterations, including reduced chemotaxis, phagocytosis, antibacterial defense, and the ability to generate reactive oxygen species...
September 25, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
Chaofan Zhang, Liang Fu, Zhengxue Xu, Houfeng Xiong, Dandan Zhou, Mingxin Huo
Intimate coupling of photocatalysis and biodegradation (ICPB) provides superior treatment for the degradation of bio-recalcitrant compounds, such as chlorophenol. Photocatalytically generated intermediates can be promptly used by the enclosed biofilms. Chlorophenol degradation can theoretically be accelerated by a co-substrate or be compromised by the competition for photocatalytic reactive oxygen species (ROS); however, studies to examine the comparison are limited in number. Non-chlorinated phenols commonly co-exist in real wastewater; thus, we evaluated the influence of phenol (hard to photo-oxidize) and pyrocatechol (easy to photo-oxidize) on the degradation of 4-chlorophenol (4CP)...
September 24, 2017: Environmental Science and Pollution Research International
C D Hickey, V Fallico, M G Wilkinson, J J Sheehan
This study investigated the differential effect of salt concentration in the outside and inside layers of brine salted cheeses on viability, culturability and enzyme activity of starter bacteria. The high-salt environment of the outside layer caused a sharp decrease in L. helveticus viability as measured by traditional plate counts. Remarkably, this was associated with lower release of intracellular enzymes (LDH), reduced levels of proteolysis and larger membrane integrity as measured by flow cytometry (FC) following classical Live/Dead staining...
February 2018: Food Microbiology
Daniel B Eckl, Linda Dengler, Marina Nemmert, Anja Eichner, Wolfgang Bäumler, Harald Huber
Photodynamic inactivation of bacteria (PIB) is based on photosensitizers which absorb light and generate reactive oxygen species (ROS), killing cells via oxidation. PIB is evaluated by comparing viability with and without irradiation, where reduction of viability in the presence of the photosensitizer without irradiation is considered as dark toxicity. This effect is controversially discussed for photosensitizers like TMPyP (5,10,15,20-Tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluensulfonate). TMPyP shows a high absorption coefficient for blue light and a high yield of ROS production, especially singlet oxygen...
September 23, 2017: Photochemistry and Photobiology
Rama K Simhadri, Eva M Fast, Rong Guo, Michaela J Schultz, Natalie Vaisman, Luis Ortiz, Joanna Bybee, Barton E Slatko, Horacio M Frydman
Endosymbiotic Wolbachia bacteria and the gut microbiome have independently been shown to affect several aspects of insect biology, including reproduction, development, life span, stem cell activity, and resistance to human pathogens, in insect vectors. This work shows that Wolbachia bacteria, which reside mainly in the fly germline, affect the microbial species present in the fly gut in a lab-reared strain. Drosophila melanogaster hosts two main genera of commensal bacteria-Acetobacter and Lactobacillus. Wolbachia-infected flies have significantly reduced titers of Acetobacter...
September 2017: MSphere
Guangyu Dong, Liang Song, Chen Tian, Yu Wang, Fang Miao, Jiabao Zheng, Chanyi Lu, Sarah Alsadun, Dana T Graves
Neutrophils play an essential role in the innate immune response to microbial infection and are particularly important in clearing bacterial infection. We investigated the role of the transcription factor FOXO1 in the response of neutrophils to bacterial challenge with Porphyromonas gingivalis in vivo and in vitro. In these experiments, the effect of lineage-specific FOXO1 deletion in LyzM.Cre(+)FOXO1(L/L) mice was compared with matched littermate controls. FOXO1 deletion negatively affected several critical aspects of neutrophil function in vivo including mobilization of neutrophils from the bone marrow (BM) to the vasculature, recruitment of neutrophils to sites of bacterial inoculation, and clearance of bacteria...
2017: Frontiers in Immunology
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