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Outer membrane vesicles

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
Ioulia Vardaki, Claire Sanchez, Pedro Fonseca, Magnus Olsson, Dimitrios Chioureas, George Rassidakis, Anders Ullén, Boris Zhivotovsky, Magnus Björkholm, Theocharis Panaretakis
The intercellular crosstalk between hematological malignancies and the tumor microenvironment is mediated by cell to cell interactions and soluble factors. One component of the secretome that is gaining increasing attention are the extracellular vesicles and in particular the exosomes. Apart from the role as vectors of molecular information, exosomes have been shown to possess intrinsic biological activity. In this study we have found that caspase-3 is activated in L88 bone marrow stroma cell-derived exosomes and identified one of the substrates to be the anti-apoptotic protein Bcl-xL...
October 14, 2016: Blood
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
Helen Y Fan, Dew Das, Heiko Heerklotz
Interactions between detergents and model membranes are well described by the three-stage model: Saturation and solubilization boundaries divide bilayer-only, bilayer-micelle co-existence, and micelle-only ranges. An underlying assumption of the model is the equilibration of detergent between the two membrane leaflets. However, many detergents partition asymmetrically at room temperature due to slow flip-flop, such as sodium dodecyl sulfate (SDS) and lysolipids. In this work, we use isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) to investigate the solubilization of unilamellar POPC vesicles by 12:0 lysophosphocholine (12:0 LPC)...
October 7, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Jan Steinkühler, Jaime Agudo-Canalejo, Reinhard Lipowsky, Rumiana Dimova
We introduce an experimental setup for modulating adhesion of giant unilamellar vesicles to a planar substrate. Adhesion is induced by the application of an external potential to a transparent indium tin oxide-coated electrode (the substrate), which enables single-vesicle studies. We demonstrate tunable and reversible adhesion of negatively charged vesicles. The adhesion energy at different potentials is calculated from the vesicle shape assessed with confocal microscopy. Two approaches for these estimates are employed: one based on the whole contour of the vesicle and a second based on the contact curvature of the membrane in the vicinity of the substrate...
October 4, 2016: Biophysical Journal
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
Thomas C Mettenleiter
Herpesviruses use a vesicle-mediated transfer of intranuclearly assembled nucleocapsids through the nuclear envelope (NE) for final maturation in the cytoplasm. The molecular basis for this novel vesicular nucleo-cytoplasmic transport is beginning to be elucidated in detail. The heterodimeric viral nuclear egress complex (NEC), conserved within the classical herpesviruses, mediates vesicle formation from the inner nuclear membrane (INM) by polymerization into a hexagonal lattice followed by fusion of the vesicle membrane with the outer nuclear membrane (ONM)...
2016: Viruses
Birgit Ploier, Anant K Menon
Scramblases translocate phospholipids across the membrane bilayer bidirectionally in an ATP-independent manner. The first scramblase to be identified and biochemically verified was opsin, the apoprotein of the photoreceptor rhodopsin. Rhodopsin is a G protein-coupled receptor localized in rod photoreceptor disc membranes of the retina where it is responsible for the perception of light. Rhodopsin's scramblase activity does not depend on its ligand 11-cis-retinal, i.e., the apoprotein opsin is also active as a scramblase...
2016: Journal of Visualized Experiments: JoVE
Stefanie Fischer, Kerstin Cornils, Thomas Speiseder, Anita Badbaran, Rudolph Reimer, Daniela Indenbirken, Adam Grundhoff, Bärbel Brunswig-Spickenheier, Malik Alawi, Claudia Lange
The biological relevance of extracellular vesicles (EV) in intercellular communication has been well established. Thus far, proteins and RNA were described as main cargo. Here, we show that EV released from human bone marrow derived mesenchymal stromal cells (BM-hMSC) also carry high-molecular DNA in addition. Extensive EV characterization revealed this DNA mainly associated with the outer EV membrane and to a smaller degree also inside the EV. Our EV purification protocol secured that DNA is not derived from apoptotic or necrotic cells...
2016: PloS One
Gabriela Jorge Da Silva, Sara Domingues
Horizontal gene transfer (HGT) is a driving force to the evolution of bacteria. The fast emergence of antimicrobial resistance reflects the ability of genetic adaptation of pathogens. Acinetobacter baumannii has emerged in the last few decades as an important opportunistic nosocomial pathogen, in part due to its high capacity of acquiring resistance to diverse antibiotic families, including to the so-called last line drugs such as carbapenems. The rampant selective pressure and genetic exchange of resistance genes hinder the effective treatment of resistant infections...
August 23, 2016: Microorganisms
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
Bingming Ou, Ying Yang, Wai Liang Tham, Lin Chen, Jitao Guo, Guoqiang Zhu
Escherichia coli strain Nissle 1917 (EcN) has been used as a probiotic. Genetic engineering has enhanced the utility of EcN in several vaccine and pharmaceutical preparations. We discuss in this mini review the genetics and physical properties of EcN. We also discuss the numerous genetic engineering strategies employed for EcN-based vaccine development, including recombinant plasmid transfer, genetic engineering of cryptic plasmids or the EcN chromosome, EcN bacterial ghosts and its outer membrane vesicles...
October 2016: Applied Microbiology and Biotechnology
Luisa Rubino, Nicoletta Guaragnella, Sergio Giannattasio
A universal feature of the replication of positive-strand RNA viruses is the association with intracellular membranes. Carnation Italian ringspot virus (CIRV) replication in plants occurs in vesicles derived from the mitochondrial outer membrane. The product encoded by CIRV ORF1, p36, is required for targeting the virus replication complex to the outer mitochondrial membrane both in plant and yeast cells. Here the yeast Saccharomyces cerevisiae was used as a model host to study the effect of CIRV p36 on cell survival and death...
September 13, 2016: Mechanisms of Ageing and Development
Sophie Melikishvili, Alexandra Poturnayova, Maksim Ionov, Maria Bryszewska, Tomáš Vary, Julius Cirak, María Ángeles Muñoz-Fernández, Rafael Gomez-Ramirez, Francisco Javier de la Mata, Tibor Hianik
In this study, dendrimers have been purposed as an alternative approach for delivery of HIV peptides to dendritic cells. We have investigated the interaction of dendriplexes formed from polyanionic HIV peptide Nef and cationic carbosilane dendrimer (CBD) with model lipid membranes - large unilamellar vesicles (LUVs), Langmuir monolayers and supported lipid membranes (sBLMs) containing various molar ratio of zwitterionic 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000] (DSPE-PEG2000)...
September 9, 2016: Biochimica et Biophysica Acta
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
Zhao Wang, Yufan Ma, Hayssam Khalil, Rutao Wang, Tingli Lu, Wen Zhao, Yang Zhang, Jamin Chen, Tao Chen
BACKGROUND: Pseudomonas aeruginosa represents a good model of antibiotic resistance. These organisms have an outer membrane with a low level of permeability to drugs that is often combined with multidrug efflux pumps, enzymatic inactivation of the drug, or alteration of its molecular target. The acute and growing problem of antibiotic resistance of bacteria to conventional antibiotics made it imperative to develop new liposome formulations for antibiotics, and investigate the fusion between liposome and bacterium...
2016: International Journal of Nanomedicine
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