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Outer membrane vesicles

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https://www.readbyqxmd.com/read/29458182/a-direct-gateway-into-the-extracellular-space-unconventional-secretion-of-fgf2-through-self-sustained-plasma-membrane-pores
#1
REVIEW
Julia P Steringer, Walter Nickel
As illustrated by a diverse set of examples in this special issue, multiple mechanisms of protein secretion have been identified in eukaryotes that do not involve the endoplasmic reticulum (ER) and the Golgi apparatus. Here we focus on the type I pathway with Fibroblast Growth Factor 2 (FGF2) being the most prominent example. Unconventional secretion of FGF2 from cells is mediated by direct protein translocation across the plasma membrane. A unique feature of this process is the ability of FGF2 to form its own membrane translocation intermediate through oligomerization and membrane insertion...
February 16, 2018: Seminars in Cell & Developmental Biology
https://www.readbyqxmd.com/read/29450619/immediate-response-mechanisms-of-gram-negative-solvent-tolerant-bacteria-to-cope-with-environmental-stress-cis-trans-isomerization-of-unsaturated-fatty-acids-and-outer-membrane-vesicle-secretion
#2
REVIEW
Christian Eberlein, Thomas Baumgarten, Stephan Starke, Hermann J Heipieper
Bacteria have evolved an array of adaptive mechanisms enabling them to survive and grow in the presence of different environmental stresses. These mechanisms include either modifications of the membrane or changes in the overall energy status, cell morphology, and cell surface properties. Long-term adaptations are dependent on transcriptional regulation, the induction of anabolic pathways, and cell growth. However, to survive sudden environmental changes, bacterial short-term responses are essential to keep the cells alive after the occurrence of an environmental stress factor such as heat shock or the presence of toxic organic solvents...
February 15, 2018: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29448354/shear-thinning-and-shear-thickening-of-a-confined-suspension-of-vesicles
#3
A Nait Ouhra, A Farutin, O Aouane, H Ez-Zahraouy, A Benyoussef, C Misbah
Widely regarded as an interesting model system for studying flow properties of blood, vesicles are closed membranes of phospholipids that mimic the cytoplasmic membranes of red blood cells. In this study we analyze the rheology of a suspension of vesicles in a confined geometry: the suspension, bound by two planar rigid walls on each side, is subject to a shear flow. Flow properties are then analyzed as a function of shear rate γ[over ̇], the concentration of the suspension ϕ, and the viscosity contrast λ=η_{in}/η_{out}, where η_{in} and η_{out} are the fluid viscosities of the inner and outer fluids, respectively...
January 2018: Physical Review. E
https://www.readbyqxmd.com/read/29439988/display-of-recombinant-proteins-on-bacterial-outer-membrane-vesicles-using-protein-ligation
#4
H Bart van den Berg van Saparoea, Diane Houben, Marien I de Jonge, Wouter S P Jong, Joen Luirink
The Escherichia coli virulence factor Hemoglobin protease (Hbp) has been engineered into a surface display system that can be expressed to high density on live E. coli and Salmonella Typhimurium bacteria or derived Outer Membrane Vesicles (OMVs). Multiple antigenic sequences can be genetically fused into the Hbp core structure for optimal exposure to the immune system. Although the Hbp display platform is relatively tolerant, increasing the number, size and complexity of integrated sequences generally lowers the expression of the fused constructs and limits the density of display...
February 9, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29413112/expression-and-immunolocalization-of-metallothioneins-mt1-mt2-and-mt3-in-rat-nephron
#5
Ivan Sabolić, Mario Škarica, Marija Ljubojević, Davorka Breljak, Carol M Herak-Kramberger, Vladiana Crljen, Nikola Ljubešić
Rodent kidneys exhibit three isoforms of metallothioneins (MTs), MT1, MT2 and MT3, with poorly characterized localization along the nephron. Here we studied in adult male Wistar rats the renal expression of MTs mRNA by end-point RT-PCR and MT proteins by immunochemical methods The expression pattern of MT1 mRNA was cortex (CO)>outer stripe (OS)=inner stripe (IS)=inner medulla (IM), of MT2 mRNA was IM>CO>IS=OS, and of MT3 mRNA was IM>CO=OS=IM. MT1/2-antibody stained with heterogeneous intensity the cell cytoplasm and nuclei in proximal tubule (PT) and thin ascending limb, whereas MT3-antibody stained weakly the cell cytoplasm in various cortical tubules and strongly the nuclei in all nephron segments...
March 2018: Journal of Trace Elements in Medicine and Biology
https://www.readbyqxmd.com/read/29412357/identification-of-the-alpha-enolase-p46-in-the-extracellular-membrane-vesicles-of-bacteroides-fragilis
#6
Thais Gonçalves Ferreira, Camilla Nunes Dos Reis Trindade, Petra Bell, André Teixeira-Ferreira, Jonas E Perales, Rossiane C Vommaro, Regina Maria Cavalcanti Pilotto Domingues, Eliane de Oliveira Ferreira
BACKGROUND: Members of the Bacteroides fragilis group are the most important components of the normal human gut microbiome, but are also major opportunistic pathogens that are responsible for significant mortality, especially in the case of bacteraemia and other severe infections, such as intra-abdominal abscesses. Up to now, several virulence factors have been described that might explain the involvement of B. fragilis in these infections. The secretion of extracellular membrane vesicles (EMVs) has been proposed to play a role in pathogenesis and symbiosis in gram-negative bacteria, by releasing soluble proteins and other molecules...
March 2018: Memórias do Instituto Oswaldo Cruz
https://www.readbyqxmd.com/read/29406241/immunization-with-pseudomonas-aeruginosa-outer-membrane-vesicles-stimulates-protective-immunity-in-mice
#7
Xiaoli Zhang, Feng Yang, Jintao Zou, Weiru Wu, Haiming Jing, Qiang Gou, Haibo Li, Jiang Gu, Quanming Zou, Jinyong Zhang
Pseudomonas aeruginosa is an opportunistic pathogen responsible for a wide range of severe nosocomial and community acquired infections, these infections are major health problems for cystic fibrosis patients and immune-compromised individuals. The emergence of multidrug-resistant isolates highlights the need to develop alternative strategies for treatment of P. aeruginosa infections. Outer membrane vesicles (OMVs) are spherical nanometer-sized proteolipids that are secreted from numerous of pathogenic Gram-negative bacteria, and a number of studies have confirmed the protective efficacy for use of OMVs as candidate vaccines...
February 14, 2018: Vaccine
https://www.readbyqxmd.com/read/29397226/natural-immunity-against-capsular-group-x-n-meningitidis-following-an-outbreak-in-togo-2007
#8
Gunnstein Norheim, Judith E Mueller, Berthe-Marie Njanpop-Lafourcade, Isabelle Delrieu, Helen Findlow, Ray Borrow, Ouli Xie, Jerry Nagaputra, Roshan Ramasamy, Christina Dold, Tsidi Agbeko Tamekloe, Christine S Rollier, Hilary Watt, Abiba Banla Kere, Lisbeth M Næss, Andrew J Pollard
BACKGROUND: Capsular group X N. meningitidis (MenX) has emerged as a cause of localized disease outbreaks in sub-Saharan Africa, but the human immune response following exposure to MenX antigens is poorly described. We therefore assessed the natural immunity against MenX in individuals who were living in an area affected by a MenX outbreak during 2007 in Togo, West Africa. During 2009, 300 healthy individuals (100 aged 3-5 years, 100 aged 13-19 years and 100 aged 20-25 years) were included in the study, and serum responses were compared with sera from age-matched controls from the U...
January 31, 2018: Vaccine
https://www.readbyqxmd.com/read/29384163/solvent-switchable-nanostructures-and-the-function-of-a-%C3%AF-amphiphile
#9
Amrita Sikder, Jayita Sarkar, Tsuneaki Sakurai, Shu Seki, Suhrit Ghosh
This manuscript reports solvent tunable functional nano-assemblies of an unsymmetrical bola-shaped π-amphiphile (NDI-PY) which consists of a hydrophobic naphthalene-diimide (NDI) chromophore connected to a non-ionic hydrophilic wedge and a pyridine group at its two opposite arms. Importantly, it contains a hydrazide group located at the hydrophobic domain between the NDI-chromophore and the hydrophilic-wedge to drive the supramolecular assembly by directional H-bonding. NDI-PY exhibits spontaneous assembly in water as well as in a highly non-polar solvent like tetra-chloroethylene (TCE) by the synergistic effect of H-bonding and π-stacking interaction...
January 31, 2018: Nanoscale
https://www.readbyqxmd.com/read/29383750/electron-microscopic-characterization-of-nuclear-egress-in-the-sea-urchin-gastrula
#10
Nicole LaMassa, Cesar Arenas-Mena, Greg R Phillips
Nuclear egress, also referred to as nuclear envelope (NE) budding, is a process of transport in which vesicles containing molecular complexes or viral particles leave the nucleus through budding from the inner nuclear membrane (INM) to enter the perinuclear space. Following this event, the perinuclear vesicles (PNVs) fuse with the outer nuclear membrane (ONM), where they release their contents into the cytoplasm. Nuclear egress is thought to participate in many functions such as viral replication, cellular differentiation, and synaptic development...
January 31, 2018: Journal of Morphology
https://www.readbyqxmd.com/read/29383371/bilayer-sheet-protrusions-and-budding-from-bilayer-membranes-induced-by-hydrolysis-and-condensation-reactions
#11
Koh M Nakagawa, Hiroshi Noguchi
Shape transformations of flat bilayer membranes and vesicles induced by hydrolysis and condensation reactions of amphiphilic molecules are studied using coarse-grained molecular dynamics simulations. The hydrolysis and condensation reactions result in the formation and dissociation of amphiphilic molecules, respectively. Asymmetric reactions between the inner and outer leaflets of a vesicle can transport amphiphilic molecules between the leaflets. It is found that the resulting area difference between the two leaflets induces bilayer sheet protrusion (BP) and budding at low reduced volumes of the vesicles, whereas BP only occurs at high reduced volumes...
January 31, 2018: Soft Matter
https://www.readbyqxmd.com/read/29377560/association-of-vibrio-cholerae-569b-outer-membrane-vesicles-with-host-cells-occurs-in-a-gm1-independent-manner
#12
Elnaz S Rasti, Megan L Schappert, Angela C Brown
The primary virulence factor of Vibrio cholerae, cholera toxin (CT), initiates a pathway in epithelial cells that leads to the severe diarrhea characteristic of cholera. Secreted CT binds to GM1 on the surface of host cells to facilitate internalization. Many bacterial toxins, including CT, have been shown to be additionally delivered via outer membrane vesicles (OMVs). A fraction of the closely related heat labile toxin (LT) produced by enterotoxigenic Escherichia coli (ETEC) has been demonstrated to reside on the surface of OMVs, where it binds GM1 to facilitate OMV internalization by host cells...
January 27, 2018: Cellular Microbiology
https://www.readbyqxmd.com/read/29375971/asymmetric-hybrid-polymer-lipid-giant-vesicles-as-cell-membrane-mimics
#13
Ariane Peyret, Emmanuel Ibarboure, Jean-François Le Meins, Sebastien Lecommandoux
Lipid membrane asymmetry plays an important role in cell function and activity, being for instance a relevant signal of its integrity. The development of artificial asymmetric membranes thus represents a key challenge. In this context, an emulsion-centrifugation method is developed to prepare giant vesicles with an asymmetric membrane composed of an inner monolayer of poly(butadiene)-b-poly(ethylene oxide) (PBut-b-PEO) and outer monolayer of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). The formation of a complete membrane asymmetry is demonstrated and its stability with time is followed by measuring lipid transverse diffusion...
January 2018: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
https://www.readbyqxmd.com/read/29374557/molecular-paths-linking-metabolic-diseases-gut-microbiota-dysbiosis-and-enterobacteria-infections
#14
REVIEW
Matteo Serino
Alterations of both ecology and functions of gut microbiota are conspicuous traits of several inflammatory pathologies, notably metabolic diseases such as obesity and type 2 diabetes. Moreover, the proliferation of enterobacteria, subdominant members of the intestinal microbial ecosystem, has been shown to be favoured by western diet, the strongest inducer of both metabolic diseases and gut microbiota dysbiosis. The inner interdependence between the host and the gut microbiota is based on a plethora of molecular mechanisms by which host and intestinal microbes modify each other...
January 25, 2018: Journal of Molecular Biology
https://www.readbyqxmd.com/read/29373591/a-trivalent-apx-fusion-protein-delivered-by-e-coli-outer-membrane-vesicles-induce-protection-against-actinobacillus-pleuropneumoniae-of-serotype-1-and-7-challenge-in-a-murine-model
#15
Kui Xu, Qin Zhao, Xintian Wen, Rui Wu, Yiping Wen, Xiaobo Huang, Yong Huang, Qigui Yan, Xinfeng Han, Xiaoping Ma, Yung-Fu Chang, Sanjie Cao
Actinobacillus pleuropneumoniae (APP) causes serious economic losses in the swine industry, and is the etiologic agent of porcine pleuropneumonia. In this study we have engineered a trivalent Apx fusion protein enclosed in outer membrane vesicles (Apxr-OMV) and studied its immunoprotective efficacy against APP serotypes 1 and 7 challenge in mice. The results showed that the IgG levels in the Apxr-OMVs immune group were significantly higher than those of the negative control (P < 0.05). Up-regulation of both Th1 (IFN-γ, IL-2) and Th2 (IL-4) cytokines were detected in splenocytes of Apxr-OMVs immune group...
2018: PloS One
https://www.readbyqxmd.com/read/29345219/transcriptional-changes-when-myxococcus-xanthus-preys-on-escherichia-coli-suggest-myxobacterial-predators-are-constitutively-toxic-but-regulate-their-feeding
#16
Paul G Livingstone, Andrew D Millard, Martin T Swain, David E Whitworth
Predation is a fundamental ecological process, but within most microbial ecosystems the molecular mechanisms of predation remain poorly understood. We investigated transcriptome changes associated with the predation of Escherichia coli by the myxobacterium Myxococcus xanthus using mRNA sequencing. Exposure to pre-killed prey significantly altered expression of 1319 predator genes. However, the transcriptional response to living prey was minimal, with only 12 genes being significantly up-regulated. The genes most induced by prey presence (kdpA and kdpB, members of the kdp regulon) were confirmed by reverse transcriptase quantitative PCR to be regulated by osmotic shock in M...
January 18, 2018: Microbial Genomics
https://www.readbyqxmd.com/read/29338048/ebola-virus-requires-a-host-scramblase-for-externalization-of-phosphatidylserine-on-the-surface-of-viral-particles
#17
Asuka Nanbo, Junki Maruyama, Masaki Imai, Michiko Ujie, Yoichiro Fujioka, Shinya Nishide, Ayato Takada, Yusuke Ohba, Yoshihiro Kawaoka
Cell surface receptors for phosphatidylserine contribute to the entry of Ebola virus (EBOV) particles, indicating that the presence of phosphatidylserine in the envelope of EBOV is important for the internalization of EBOV particles. Phosphatidylserine is typically distributed in the inner layer of the plasma membrane in normal cells. Progeny virions bud from the plasma membrane of infected cells, suggesting that phosphatidylserine is likely flipped to the outer leaflet of the plasma membrane in infected cells for EBOV virions to acquire it...
January 16, 2018: PLoS Pathogens
https://www.readbyqxmd.com/read/29320681/intrinsic-curvature-mediated-transbilayer-coupling-in-asymmetric-lipid-vesicles
#18
Barbara Eicher, Drew Marquardt, Frederick A Heberle, Ilse Letofsky-Papst, Gerald N Rechberger, Marie-Sousai Appavou, John Katsaras, Georg Pabst
We measured the effect of intrinsic lipid curvature, J0, on structural properties of asymmetric vesicles made of palmitoyl-oleoyl-phosphatidylethanolamine (POPE; J0<0) and palmitoyl-oleoyl-phosphatidylcholine (POPC; J0∼0). Electron microscopy and dynamic light scattering were used to determine vesicle size and morphology, and x-ray and neutron scattering, combined with calorimetric experiments and solution NMR, yielded insights into leaflet-specific lipid packing and melting processes. Below the lipid melting temperature we observed strong interleaflet coupling in asymmetric vesicles with POPE inner bilayer leaflets and outer leaflets enriched in POPC...
January 9, 2018: Biophysical Journal
https://www.readbyqxmd.com/read/29320408/outer-membrane-vesicle-vaccines-from-biosafe-surrogates-prevent-acute-lethal-glanders-in-mice
#19
Michael H Norris, Mohammad S R Khan, Sunisa Chirakul, Herbert P Schweizer, Apichai Tuanyok
Burkholderia mallei is a host-adapted Gram-negative mammalian pathogen that causes the severe disease glanders. Glanders can manifest as a rapid acute progression or a chronic debilitating syndrome primarily affecting solipeds and humans in close association with infected animals. In USA, B. mallei is classified as one of the most important bacterial biothreat agents. Presently, there is no licensed glanders vaccine available for humans or animals. In this work, outer membrane vesicles (OMVs) were isolated from three attenuated biosafe bacterial strains, Burkholderia pseudomallei Bp82, B...
January 10, 2018: Vaccines
https://www.readbyqxmd.com/read/29316978/in-vivo-testing-of-novel-vaccine-prototypes-against-actinobacillus-pleuropneumoniae
#20
Fabio Antenucci, Cyrielle Fougeroux, Alannah Deeney, Cathrine Ørskov, Andrew Rycroft, Peter Johannes Holst, Anders Miki Bojesen
Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is a Gram-negative bacterium that represents the main cause of porcine pleuropneumonia in pigs, causing significant economic losses to the livestock industry worldwide. A. pleuropneumoniae, as the majority of Gram-negative bacteria, excrete vesicles from its outer membrane (OM), accordingly defined as outer membrane vesicles (OMVs). Thanks to their antigenic similarity to the OM, OMVs have emerged as a promising tool in vaccinology. In this study we describe the in vivo testing of several vaccine prototypes for the prevention of infection by all known A...
January 9, 2018: Veterinary Research
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