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Yoo Jeong Kim, Hyejin Jeon, Seok Hyeon Na, Hyo Il Kwon, Gati Noble Selasi, Asiimwe Nicholas, Tae In Park, Sang Hwa Lee, Je Chul Lee
Stenotrophomonas maltophilia has become one of the most prevalent opportunistic pathogens in hospitalized patients. This microorganism secretes outer membrane vesicles (OMVs), but the pathogenesis of S. maltophilia as it relates to OMVs has not been characterized. This study investigated the cytotoxic activity of S. maltophilia OMVs and their ability to induce inflammatory responses both in vitro and in vivo S. maltophilia ATCC 13637 and two clinical isolates were found to secrete spherical OMVs during in vitro culture...
October 17, 2016: Pathogens and Disease
Ingrid Palma-Martínez, Andrea Guerrero-Mandujano, Manuel J Ruiz-Ruiz, Cecilia Hernández-Cortez, José Molina-López, Virgilio Bocanegra-García, Graciela Castro-Escarpulli
Shiga-like toxins (Stx) represent a group of bacterial toxins involved in human and animal diseases. Stx is produced by enterohemorrhagic Escherichia coli, Shigella dysenteriae type 1, Citrobacter freundii, and Aeromonas spp.; Stx is an important cause of bloody diarrhea and hemolytic uremic syndrome (HUS). The aim of this study was to identify the stx1/stx2 genes in clinical strains and outer membrane vesicles (OMVs) of Aeromonas spp., 66 strains were isolated from children who live in Mexico City, and Stx effects were evaluated in Vero cell cultures...
2016: Frontiers in Microbiology
Qiong Liu, Qing Liu, Jie Yi, Kang Liang, Bo Hu, Xiangmin Zhang, Roy Curtiss, Qingke Kong
Outer membrane vesicles (OMVs) isolated from Salmonella Typhimurium are potentially useful for developing subunit vaccines because of high immunogenicity and protective efficacy. However, flagella might remain in OMV pellets following OMV purification, resulting in non-essential immune responses and counteraction of bacterial protective immune responses when developing a vaccine against infection of multiple serotypes Salmonella. In this study, a flagellin-deficient S. Typhimurium mutant was constructed. Lipopolysaccharide profiles, protein profiles and cryo-electron microscopy revealed that there were no significant differences between the wild-type and mutant OMVs, with the exception of a large amount of flagellin in the wild-type OMVs...
October 4, 2016: Scientific Reports
Nichole Orench-Rivera, Meta Kuehn
Over the past two decades, researchers studying both microbial and host cell communities have gained an appreciation for the ability of bacteria to produce, regulate, and functionally utilize outer membrane vesicles (OMVs) as a means to survive and interact with their cellular and acellular environments. Common ground has emerged, as it appears that vesicle production is an environmentally-controlled and specific secretion process, however it has been challenging to discover the principles that govern fundamentals of vesicle-mediated transport...
September 27, 2016: Cellular Microbiology
Kin Chan, Clifford Shone, J Richard Hesp
PURPOSE: The focus of this study was to characterise the effect of clinically relevant stress inducing conditions on the production and composition of proinflammatory outer membrane vesicles (OMVs) produced from ST131 ExPEC clinical isolates. EXPERIMENTAL DESIGN: A label-free method (SINQ) was used to identify changes in the respective OMV proteomes following exposure of the ExPEC strains to antibiotics and low iron. Nanoparticle tracking analysis was used to quantify changes in abundance and size of OMVs produced by the gentamicin resistant (GenR) and sensitive (GenS) ExPEC strains...
September 26, 2016: Proteomics. Clinical Applications
Gro Tunheim, Marianne Arnemo, Lisbeth M Naess, Gunnstein Norheim, Luis Garcia, Daniel Cardoso, Aleida Mandiarote, Domingo Gonzalez, Kalpana Sinnadurai, Åse-Karine Fjeldheim, Karin Bolstad, Einar Rosenqvist
Meningococci (Neisseria meningiditis) of serogroups A and W have caused large epidemics of meningitis in sub-Saharan Africa for decades, and affordable and multivalent vaccines, effective in all age groups, are needed. A bivalent serogroup A and W (A + W) meningococcal vaccine candidate consisting of deoxycholate-extracted outer membrane vesicles (OMV) from representative African disease isolates was previously found to be highly immunogenic in outbred mice when formulated with the adjuvant aluminium hydroxide (AH)...
November 2016: APMIS: Acta Pathologica, Microbiologica, et Immunologica Scandinavica
Harald Moser, Walter Pölz, Johannes Paul Waclawek, Johannes Ofner, Bernhard Lendl
The implementation of a sensitive and selective as well as industrial fit gas sensor prototype based on wavelength modulation spectroscopy with second harmonic detection (2f-WMS) employing an 8-μm continuous-wave distributed feedback quantum cascade laser (CW-DFB-QCL) for monitoring hydrogen sulfide (H2S) at sub-ppm levels is reported. Regarding the applicability for analytical and industrial process purposes aimed at petrochemical environments, a synthetic methane (CH4) matrix of up to 1000 ppmv together with a varying H2S content was chosen as the model environment for the laboratory-based performance evaluation performed at TU Wien...
September 17, 2016: Analytical and Bioanalytical Chemistry
Chih-Yun Hsia, Linxiao Chen, Rohit R Singh, Matthew P DeLisa, Susan Daniel
The bacterial outer membrane (OM) is a barrier containing membrane proteins and liposaccharides that fulfill crucial functions for Gram-negative bacteria. With the advent of drug-resistant bacteria, it is necessary to understand the functional role of this membrane and its constituents to enable novel drug designs. Here we report a simple method to form an OM-like supported bilayer (OM-SB), which incorporates native lipids and membrane proteins of gram-negative bacteria from outer membrane vesicles (OMVs). We characterize the formation of OM-SBs using quartz crystal microbalance with dissipation (QCM-D) and fluorescence microscopy...
2016: Scientific Reports
Richard C Laughlin, Robert C Alaniz
Characterization of host microbial interactions typically occurs on the cellular or protein level. Recently, a more thorough and accurate appreciation of cellular interactions has come into better focus with improved understanding of membrane vesicles (OMV). While OMVs are documented primarily in Gram-negative bacteria, certain Gram-positive species generate these structures, despite the obvious physical limitations of the cell envelope. Here, we briefly review the current understanding of OMVs in content and function, their role in pathogenesis, and the consequences of somatic cell gene expression on these events...
September 2, 2016: Gut Microbes
Qiong Liu, Qing Liu, Jie Yi, Kang Liang, Tian Liu, Kenneth L Roland, Yanlong Jiang, Qingke Kong
Salmonella enterica cause diarrheal and systemic diseases and are of considerable concern worldwide. Vaccines that are cross-protective against multiple serovars could provide effective control of Salmonella-mediated diseases. Bacteria-derived outer membrane vesicles (OMVs) are highly immunogenic and are capable of eliciting protective immune responses. Alterations in lipopolysaccharide (LPS) length can result in outer membrane remodeling and composition of outer membrane proteins (OMPs) changing. In this study, we investigated the impact of truncated LPS on both the production and immunogenicity of Salmonella OMVs, including the ability of OMVs to elicit cross-protection against challenge by heterologous Salmonella strains...
August 25, 2016: International Journal of Medical Microbiology: IJMM
Rishi Pathirana, Maria Kaparakis-Liaskos
Outer membrane vesicles (OMV) were first described approximately 50 years ago, and for many years were considered to be an artefact of bacterial growth. Since that initial discovery, it has become evident that OMVs are produced by almost all Gram-negative bacteria as part of their normal growth in addition to driving pathogenesis within the host. More recently, the identification of membrane vesicle (MV) production by some Gram-positive bacteria, parasites, fungi, mycobacteria and infected host cells has significantly broadened the field of MV production and emphasised their importance to pathogenesis...
August 26, 2016: Cellular Microbiology
Joachim Reidl
Recent research has focused on the biological role of outer membrane vesicles (OMVs), which are derived from the outer membranes (OMs) of Gram-negative bacteria, and their potential exploitation as therapeutics. OMVs have been characterized in many ways and functions. Until recently, research focused on hypothetical and empirical models that addressed the molecular mechanisms of OMV biogenesis, such as vesicles bulging from the OM in various ways. The recently reported study by Elhenawy et al. (mBio 7:e00940-16, 2016, http://dx...
2016: MBio
Eloise J O'Donoghue, Anne Marie Krachler
Bacterial outer membrane vesicles (OMVs) are nano-sized compartments consisting of a lipid bilayer that encapsulates periplasm-derived, luminal content. OMVs, which pinch off of Gram-negative bacteria, are now recognised as a generalised secretion pathway which provides a means to transfer cargo to other bacterial cells as well as eukaryotic cells. Compared with other secretion systems, OMVs can transfer a chemically extremely diverse range of cargo, including small molecules, nucleic acids, proteins and lipids to proximal cells...
August 16, 2016: Cellular Microbiology
J T Stahmeyer, S Rossol, F Bert, S Liersch, C Krauth
The treatment of chronic hepatitis C has considerably changed with the introduction of recent direct acting antivirals. These antivirals have sustained virologic response (SVR) rates above 90 % as well as reduced toxicity and treatment duration. Therefore, current German guidelines recommend these interferon-free regimens as first-choice treatment. Nevertheless, recent developments were accompanied by a significant increase in treatment costs, which led to extensive discussions on reasonable pharmaceutical prices...
August 2016: Zeitschrift Für Gastroenterologie
María-Alexandra Cañas, Rosa Giménez, María-José Fábrega, Lorena Toloza, Laura Baldomà, Josefa Badia
Interactions between intestinal microbiota and the human host are complex. The gut mucosal surface is covered by a mucin layer that prevents bacteria from accessing the epithelial cells. Thus, the crosstalk between microbiota and the host mainly rely on secreted factors that can go through the mucus layer and reach the epithelium. In this context, vesicles released by commensal strains are seen as key players in signaling processes in the intestinal mucosa. Studies with Gram-negative pathogens showed that outer membrane vesicles (OMVs) are internalized into the host cell by endocytosis, but the entry mechanism for microbiota-derived vesicles is unknown...
2016: PloS One
Ryoma Nakao, Hideki Hasegawa, Bai Dongying, Makoto Ohnishi, Hidenobu Senpuku
Periodontitis is the most prevalent infectious disease and related to oral and systemic health, therefore novel prophylaxis to prevent the disease is highly desirable. Here, we assessed the outer membrane vesicles (OMVs) of a keystone periodontal pathogen, Porphyromonas gingivalis, as a candidate mucosal immunogen and adjuvant for a periodontitis vaccine. The structural and functional stability of OMVs, demonstrated by proteinase K resistance and ability to withstand long-term storage, are considered advantageous for carrying the OMV components into the host immune system...
August 31, 2016: Vaccine
Wael Elhenawy, Michael Bording-Jorgensen, Ezequiel Valguarnera, M Florencia Haurat, Eytan Wine, Mario F Feldman
UNLABELLED: Outer membrane vesicles (OMV) are proposed to mediate multiple functions during pathogenesis and symbiosis. However, the mechanisms responsible for OMV formation remain poorly understood. It has been shown in eukaryotic membranes that lipids with an inverted-cone shape favor the formation of positive membrane curvatures. Based on these studies, we formulated the hypothesis that lipid A deacylation might impose shape modifications that result in the curvature of the outer membrane (OM) and subsequent OMV formation...
2016: MBio
Daniel J Bretl, Susanne Müller, Kayla M Ladd, Samantha N Atkinson, John R Kirby
Myxococcus xanthus is an environmental bacterium with two forms of motility. One type, known as social motility, is dependent on extension and retraction of Type-IV pili (T4P) and production of extracellular polysaccharides (EPS). Several signaling systems have been linked to regulation of T4P-dependent motility. In particular, expression of the pilin subunit pilA requires the PilSR two-component signaling system (TCS). A second TCS, PilS2R2, encoded within the same locus that encodes PilSR, has also been linked to M...
October 2016: Molecular Microbiology
Renata Godlewska, Maciej Kuczkowski, Agnieszka Wyszyńska, Joanna Klim, Katarzyna Derlatka, Anna Woźniak-Biel, Elżbieta K Jagusztyn-Krynicka
Campylobacter jejuni is the most prevalent cause of a food-borne gastroenteritis in the developed world, with poultry being the main source of infection. Campylobacter jejuni, like other Gram-negative bacteria, constitutively releases outer membrane vesicles (OMVs). OMVs are highly immunogenic, can be taken up by mammalian cells, and are easily modifiable by recombinant engineering. We have tested their usefulness for an oral (in ovo) vaccination of chickens. Four groups of 18-day-old chicken embryos (164 animals) underwent injection of wt C...
October 2016: Applied Microbiology and Biotechnology
Matteo M E Metruccio, David J Evans, Manal M Gabriel, Jagath L Kadurugamuwa, Suzanne M J Fleiszig
Pseudomonas aeruginosa is a leading cause of human morbidity and mortality that often targets epithelial surfaces. Host immunocompromise, or the presence of indwelling medical devices, including contact lenses, can predispose to infection. While medical devices are known to accumulate bacterial biofilms, it is not well understood why resistant epithelial surfaces become susceptible to P. aeruginosa. Many bacteria, including P. aeruginosa, release outer membrane vesicles (OMVs) in response to stress that can fuse with host cells to alter their function...
2016: Frontiers in Microbiology
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