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Outer membrane vesicle

Worawit Intrchom, Megha Thakkar, Raymond F Hamilton, Andrij Holian, Somenath Mitra
We demonstrate for the first time the toxicity of carbon nanotube (CNT) metal hybrids on freshwater algae. Carbon nanotube-silver (CNT-Ag) and platinum hybrids (CNT-Pt) were synthesized and exposed to Chlamydomonas reinhardtii (C. reinhardtii), and their toxicity was compared to the pure metal salts. Interactions between CNT-metal and algae were studied using electron microscopy and it was observed that while outer membrane of the algal cell was damaged as a result of Ag+ toxicity from pure Ag, the CNT-Ag only caused the distortion of the cell wall...
October 17, 2018: Scientific Reports
Magdalena Banach-Orłowska, Kamil Jastrzębski, Jarosław Cendrowski, Małgorzata Maksymowicz, Karolina Wojciechowska, Michał Korostyński, Dimitri Moreau, Jean Gruenberg, Marta Miaczynska
Cytokine receptors, such as tumor necrosis factor receptor I (TNFRI) and lymphotoxin β receptor (LTβR), activate inflammatory NF-κB signaling upon stimulation. We previously demonstrated that depletion of ESCRT components leads to endosomal accumulation of TNFRI and LTβR, and their ligand-independent signaling to NF-κB. Here, we studied if other perturbations of the endolysosomal system could trigger intracellular accumulation and signaling of ligand-free LTβR. While depletion of CORVET had no effect, knockdown of HOPS or Rab7, or pharmacological inhibition of lysosomal degradation, caused endosomal accumulation of LTβR and its increased interactions with TRAF2/TRAF3 signaling adaptors...
October 17, 2018: Journal of Cell Science
Justin B Nice, Nataliya V Balashova, Scott C Kachlany, Evan Koufos, Eric Krueger, Edward T Lally, Angela C Brown
The Gram-negative bacterium, Aggregatibacter actinomycetemcomitans, has been associated with localized aggressive periodontitis (LAP). In particular, highly leukotoxic strains of A. actinomycetemcomitans have been more closely associated with this disease, suggesting that LtxA is a key virulence factor for A. actinomycetemcomitans . LtxA is secreted across both the inner and outer membranes via the Type I secretion system, but has also been found to be enriched within outer membrane vesicles (OMVs), derived from the bacterial outer membrane...
October 13, 2018: Toxins
Joshua Hutchings, Viktoriya Stancheva, Elizabeth A Miller, Giulia Zanetti
Eukaryotic cells employ membrane-bound carriers to transport cargo between compartments in a process essential to cell functionality. Carriers are generated by coat complexes that couple cargo capture to membrane deformation. The COPII coat mediates export from the endoplasmic reticulum by assembling in inner and outer layers, yielding carriers of variable shape and size that allow secretion of thousands of diverse cargo. Despite detailed understanding of COPII subunits, the molecular mechanisms of coat assembly and membrane deformation are unclear...
October 8, 2018: Nature Communications
A P G Dingeldein, T Sparrman, G Gröbner
Mitochondria are crucially involved in the removal of eukaryotic cells by the intrinsic pathway of programmed cell death (apoptosis). The mitochondrion's outer membrane (MOM) is the platform where this pathway takes place. Upon oxidative stress triggering apoptotic action, the MOM undergoes permeabilization and release of cytochrome c, ultimately causing cell death. This membrane perforation is regulated not only by opposing members of the Bcl-2 protein family meeting at the MOM but also actively the membrane itself...
October 5, 2018: Biochimica et biophysica acta. Biomembranes
Eilien Schulz, Adriely Goes, Ronald Garcia, Fabian Panter, Marcus Koch, Rolf Müller, Kathrin Fuhrmann, Gregor Fuhrmann
Up to 25,000 people die each year from resistant infections in Europe alone, with increasing incidence. It is estimated that a continued rise in bacterial resistance by 2050 would lead up to 10 million annual deaths worldwide, exceeding the incidence of cancer deaths. Although the design of new antibiotics is still one way to tackle the problem, pharmaceutical companies investigate far less into new drugs than 30 years ago. Incorporation of antibiotics into nanoparticle drug carriers ("nanoantibiotics") is currently investigated as a promising strategy to make existing antibiotics regain antimicrobial strength and overcome certain types of microbial drug resistance...
October 5, 2018: Journal of Controlled Release: Official Journal of the Controlled Release Society
Gabriel Gustafsson, Camilla Lööv, Emma Persson, Diana F Lázaro, Shuko Takeda, Joakim Bergström, Anna Erlandsson, Dag Sehlin, Leonora Balaj, Bence György, Martin Hallbeck, Tiago F Outeiro, Xandra O Breakefield, Bradley T Hyman, Martin Ingelsson
In Parkinson's disease and other Lewy body disorders, the propagation of pathology has been accredited to the spreading of extracellular α-synuclein (α-syn). Although the pathogenic mechanisms are not fully understood, cell-to-cell transfer of α-syn via exosomes and other extracellular vesicles (EVs) has been reported. Here, we investigated whether altered molecular properties of α-syn can influence the distribution and secretion of α-syn in human neuroblastoma cells. Different α-syn variants, including α-syn:hemi-Venus and disease-causing mutants, were overexpressed and EVs were isolated from the conditioned medium...
October 4, 2018: Cellular and Molecular Neurobiology
Lei Wang, Yugo Iwasaki, Kiran K Andra, Kalpana Pandey, Anant K Menon, Peter Bütikofer
Members of the G protein-coupled receptor and transmembrane protein 16 (TMEM16) protein families are phospholipid scramblases that facilitate rapid, bidirectional movement of phospholipids across a membrane bilayer in an ATP-independent manner. On reconstitution into large unilamellar vesicles, these proteins scramble more than 10,000 lipids per protein per second as measured with core-constituted fluorescent nitrobenzoxadiazole (NBD)-labeled phospholipids. Although NBD-labeled phospholipids are ubiquitously used as reporters of scramblase activity, it remains unclear whether the NBD modification influences the quantitative outcomes of the scramblase assay...
October 4, 2018: Journal of Biological Chemistry
Matthias J H Gerritzen, Ronald H W Maas, Jan van den Ijssel, Lonneke van Keulen, Dirk E Martens, René H Wijffels, Michiel Stork
BACKGROUND: Outer membrane vesicles (OMVs) are nanoparticles released by Gram-negative bacteria and can be used as vaccines. Often, detergents are used to promote release of OMVs and to remove the toxic lipopolysaccharides. Lipopolysaccharides can be detoxified by genetic modification such that vesicles spontaneously produced by bacteria can be directly used as vaccines. The use of spontaneous OMVs has the advantage that no separate extraction step is required in the purification process...
October 3, 2018: Microbial Cell Factories
Soheila Hekmat, Seyed Mehdi Sadat, Mohammad Mehdi Aslani, Mehdi Mahdavi, Azam Bolhassani, Fateme Asgar Halvaee, Seyed Mohammad Mahdi Ghahari, Mohammad Reza Aghasadeghi, Seyed Davar Siadat
Background: A licensed vaccine against hepatitis C virus (HCV) has not become available to date. The stability and antigenicity of a targeted synthesized recombinant fusion protein consisting of a truncated core and NS3 (rC/N) of HCV had been predicted. Although safe antigens, recombinant proteins are not efficacious vaccines without adjuvants. The present study evaluated the immunogenicity of rC/N as a bipartite antigen accompanied by Neisseria meningitidis serogroup B outer membrane vesicles (NMB OMVs) in BALB/c mice...
October 3, 2018: Iranian Biomedical Journal
Johannes Thoma, Selen Manioglu, David Kalbermatter, Patrick D Bosshart, Dimitrios Fotiadis, Daniel J Müller
Most studies characterizing the folding, structure, and function of membrane proteins rely on solubilized or reconstituted samples. Whereas solubilized membrane proteins lack the functionally important lipid membrane, reconstitution embeds them into artificial lipid bilayers, which lack characteristic features of cellular membranes including lipid diversity, composition and asymmetry. Here, we utilize outer membrane vesicles (OMVs) released from Escherichia coli to study outer membrane proteins (Omps) in the native membrane environment...
2018: Communications biology
Huihui Gao, Yao Gao, Chenhao Yang, Daqian Dong, Jinmeng Yang, Guofan Peng, Jiacheng Peng, Yuanxian Wang, Chuanying Pan, Wuzi Dong
This study focuses on the effect of outer membrane vesicles (OMVs) in gram-negative bacteria on boar sperm function during in vitro storage. In the 40 ejaculates collected from Guangzhong Black boar, six gram-negative bacterial species were detected by 16S rDNA sequencing, of which Proteus mirabilis was the main contaminating bacterium. The OMVs of P. mirabilis were isolated by gradient ultracentrifugation. To reveal the effect of OMVs on boar sperm, different OMV concentrations were added to the Modena medium during sperm storage at 17 °C...
October 2018: Veterinary Microbiology
Francesca Micoli, Simona Rondini, Renzo Alfini, Luisa Lanzilao, Francesca Necchi, Aurel Negrea, Omar Rossi, Cornelia Brandt, Simon Clare, Pietro Mastroeni, Rino Rappuoli, Allan Saul, Calman A MacLennan
Nontyphoidal Salmonellae cause a devastating burden of invasive disease in sub-Saharan Africa with high levels of antimicrobial resistance. Vaccination has potential for a major global health impact, but no licensed vaccine is available. The lack of commercial incentive makes simple, affordable technologies the preferred route for vaccine development. Here we compare equivalent Generalized Modules for Membrane Antigens (GMMA) outer membrane vesicles and O-antigen-CRM197 glycoconjugates to deliver lipopolysaccharide O-antigen in bivalent Salmonella Typhimurium and Enteritidis vaccines...
October 9, 2018: Proceedings of the National Academy of Sciences of the United States of America
Eric N Salgado, Brian Garcia Rodriguez, Nagarjun Narayanaswamy, Yamuna Krishnan, Stephen C Harrison
Bound calcium ions stabilize many non-enveloped virions. Loss of Ca2+ from these particles appears to be a regulated part of entry or uncoating. The outer layer of an infectious rotavirus triple-layered particle (TLP) comprises a membrane-interacting protein (VP4) anchored by a Ca2+ stabilized protein (VP7). Membrane coupled, conformational changes in VP4 (cleaved to VP8* and VP5*) and dissociation of VP4 and VP7 accompany penetration of the double layered, inner capsid particle (DLP) into the cytosol. Removal of Ca2+ in vitro strips away both outer-layer proteins; we and others have postulated that loss of Ca2+ triggers molecular events in viral penetration...
September 26, 2018: Journal of Virology
Sujinna Lekmeechai, Yu-Ching Su, Marta Brant, Maria Alvarado-Kristensson, Anna Vallström, Ikenna Obi, Anna Arnqvist, Kristian Riesbeck
Outer membrane vesicles (OMVs) play an important role in the persistence of Helicobacter pylori infection. Helicobacter OMVs carry a plethora of virulence factors, including catalase (KatA), an antioxidant enzyme that counteracts the host respiratory burst. We found KatA to be enriched and surface-associated in OMVs compared to bacterial cells. This conferred OMV-dependent KatA activity resulting in neutralization of H2 O2 and NaClO, and rescue of surrounding bacteria from oxidative damage. The antioxidant activity of OMVs was abolished by deletion of KatA...
2018: Frontiers in Microbiology
Ying Lv, Sheng Zhou, Shengyan Gao, Hongyu Deng
Many viruses, enveloped or non-enveloped, remodel host membrane structures for their replication, assembly and escape from host cells. Herpesviruses are important human pathogens and cause many diseases. As large enveloped DNA viruses, herpesviruses undergo several complex steps to complete their life cycles and produce infectious progenies. Firstly, herpesvirus assembly initiates in the nucleus, producing nucleocapsids that are too large to cross through the nuclear pores. Nascent nucleocapsids instead bud at the inner nuclear membrane to form primary enveloped virions in the perinuclear space followed by fusion of the primary envelopes with the outer nuclear membrane, to translocate the nucleocapsids into the cytoplasm...
September 21, 2018: Protein & Cell
Ajay K Monnappa, Wasimul Bari, Jeong Kon Seo, Robert J Mitchell
In this study we show Yersinia pseudotuberculosis secretes membrane vesicles (MVs) that contain different proteins and virulence factors depending on the strain. Although MVs from Y. pseudotuberculosis YPIII and ATCC 29833 had many proteins in common (68.8% of all the proteins identified), those located in the outer membrane fraction differed significantly. For instance, the MVs from Y. pseudotuberculosis YPIII harbored numerous Yersinia outer proteins (Yops) while they were absent in the ATCC 29833 MVs. Another virulence factor found solely in the YPIII MVs was the cytotoxic necrotizing factor (CNFy), a toxin that leads to multinucleation of host cells...
September 21, 2018: Scientific Reports
Debaki R Howlader, Hemanta Koley, Ritam Sinha, Suhrid Maiti, Ushasi Bhaumik, Priyadarshini Mukherjee, Shanta Dutta
Salmonella Typhi and Salmonella Paratyphi A are the leading causative agents of enteric fever which cause morbidity and mortality worldwide. Currently, there is no combination vaccine which could protect infection from both the strains. In this paper, we are focusing on the development of a novel bivalent typhoidal Outer Membrane Vesicles (OMVs) based immunogen against enteric fever. We have isolated Salmonella Typhi and Paratyphi A OMVs and also characterized OMVs associated antigens. Then we immunized adult mice with three doses of our newly formulated bivalent immunogen orally (25 μg/200 μl)...
2018: PloS One
Antoine Malabirade, Janine Habier, Anna Heintz-Buschart, Patrick May, Julien Godet, Rashi Halder, Alton Etheridge, David Galas, Paul Wilmes, Joëlle V Fritz
Bacterial outer membrane vesicles (OMVs), as well as OMV-associated small RNAs, have been demonstrated to play a role in host-pathogen interactions. The presence of larger RNA transcripts in OMVs has been less studied and their potential role in host-pathogen interactions remains largely unknown. Here we analyze RNA from OMVs secreted by Salmonella enterica serovar Typhimurium ( S. Typhimurium) cultured under different conditions, which mimic host-pathogen interactions. S. Typhimurium was grown to exponential and stationary growth phases in minimal growth control medium (phosphate-carbon-nitrogen, PCN), as well as in acidic and phosphate-depleted PCN, comparable to the macrophage environment and inducing therefore the expression of Salmonella pathogenicity island 2 (SPI-2) genes...
2018: Frontiers in Microbiology
Brian Belardi, Sungmin Son, Michael D Vahey, Jinzhi Wang, Jianghui Hou, Daniel A Fletcher
Tight junctions have been hypothesized to act as molecular fences in the plasma membrane of epithelial cells, helping to form differentiated apical and basolateral domains. While this fence function is believed to arise from the interaction of four-pass transmembrane claudins, the complexity of tight junctions has made direct evidence of their role as a putative diffusion barrier difficult to obtain. Here we address this challenge by reconstituting claudin-4 into giant unilamellar vesicles using microfluidic jetting...
September 12, 2018: Journal of Cell Science
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