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Outer membrane vesicles

Ji Hyun Kim, Jaewook Lee, Kyong-Su Park, Sung-Wook Hong, Yong Song Gho
Sepsis is characterized by systemic inflammatory response syndrome (SIRS) accompanied with infection. Gram-negative bacteria can evoke sepsis by activating the host immune system, such as the release of IL-6 and TNF-α, through their virulence factors. Outer membrane vesicles (OMVs), nanosized bilayered proteolipids derived from Gram-negative bacteria, harbor various virulence factors and are shown to induce SIRS. Here, drugs are repositioned to alleviate SIRS caused by Gram-negative bacterial OMVs. Using novel OMV-based drug screening systems, a total of 178 commercially available drugs are primarily screened, and a total of 18 repositioned drug candidates are found to effectively block IL-6 and TNF-α production from OMV-stimulated macrophages...
April 23, 2018: Advanced Healthcare Materials
Nathan J Alves, Martin H Moore, Brandy J Johnson, Scott Nathan Dean, Kendrick Bruce Turner, Igor L Medintz, Scott A Walper
While technologies for the remediation of chemical contaminants continue to emerge, growing interest in Green technologies has led researchers to explore natural catalytic mechanisms derived from microbial species. One such method, enzymatic degradation, offers an alternative to harsh chemical catalysts and resins. Recombinant enzymes, however, are often too labile or show limited activity when challenged with non-ideal environmental conditions that may vary in salinity, pH, or other physical properties. Here, we demonstrate how phosphotriesterase encapsulated in a bacterial outer membrane vesicle (OMV) can be used to degrade the organophosphate chemical warfare agent (CWA) simulant paraoxon in environmental water samples...
April 19, 2018: ACS Applied Materials & Interfaces
Rodolfo Villena, Marco Aurelio P Safadi, María Teresa Valenzuela, Juan P Torres, Adam Finn, Miguel O'Ryan
Meningococcal disease (MD) is a major cause of meningitis and sepsis worldwide, with a high case fatality rate and frequent sequelae. Neisseria meningitidis serogroups A, B, C, W, X and Y are responsible for most of these life-threatening infections, and its unpredictable epidemiology can cause outbreaks in communities, with significant health, social and economic impact. Currently, serogroup B is the main cause of MD in Europe and North America and one of the most prevalent serogroups in Latin America. Mass vaccination strategies using polysaccharide vaccines have been deployed since the 1970s and the use of conjugate vaccines has controlled endemic and epidemic disease caused by serogroups A, C, W and Y and more recently serogroup B using geographically-specific outer membrane vesicle based vaccines...
April 18, 2018: Human Vaccines & Immunotherapeutics
Ji-Jie Pang, Zhuo Yang, Roy A Jacoby, Samuel M Wu
Some mammalian rod bipolar cells (RBCs) can receive excitatory chemical synaptic inputs from both rods and cones (DBCR2 ), but anatomical evidence for mammalian cone-RBC contacts has been sparse. We examined anatomical cone-RBC contacts using neurobiotin (NB) to visualize individual mouse cones and standard immuno-markers to identify RBCs, cone pedicles and synapses in mouse and baboon retinas. Peanut agglutinin (PNA) stained the basal membrane of all cone pedicles, and mouse cones were positive for red/green (R/G)-opsin, whereas baboon cones were positive for calbindin D-28k...
April 18, 2018: Journal of Comparative Neurology
Xifeng Wang, Zhiquan Wang, Xinfeng Bai, Yue Zhao, Weican Zhang, Xuemei Lu
Cytophaga hutchinsonii is a gliding Gram-negative bacterium in the phylum Bacteroidetes with the capability to digest crystalline cellulose rapidly, but the mechanism is unclear. In this study, deletion of chu_0125 , encoding a homolog of the peptidoglycan-associated lipoprotein (Pal), was determined to prevent degradation of the crystalline region of cellulose. We found that the chu_0125 deletion mutant grew normally in regenerated amorphous cellulose medium but displayed defective growth in crystalline cellulose medium and increased the degree of crystallinity of Avicel...
2018: Frontiers in Microbiology
Tamara Reyes-Robles, Rebecca S Dillard, Lynne S Cairns, Cecilia A Silva-Valenzuela, Max Housman, Afsar Ali, Elizabeth R Wright, Andrew Camilli
Novel preventatives could help in efforts to limit Vibrio cholerae infection and the spread of cholera. Bacteriophage (or phage) treatment has been proposed to be an alternative intervention, given the rapid replication of virulent phages, prey specificity, and relative ease of finding new virulent phages. Phage tropism is dictated in part by the presence of phage receptors on the bacterial surface. While many phages that can kill V. cholerae have been isolated, whether this pathogen is able to defend itself by neutralizing phage binding is unknown...
April 16, 2018: Journal of Bacteriology
David E Whitworth
Predation is an extreme form of competition between bacteria, involving the secretion of antimicrobial substances by predators, often packaged within outer membrane vesicles (OMVs). Recent studies into the Myxococcus xanthus/Escherichia coli predator/prey relationship have illuminated transcriptional changes during predation, identifying likely targets of predatory attack in the prey and nutrient assimilation strategies of the predator. Abundant non-coding RNAs can be observed in the predator and prey transcriptomes, with evidence of predation-dependent regulation of RNA levels...
April 10, 2018: FEMS Microbiology Letters
Bo Tang, Da-Wei He, Dian Li, Wen-Hao Guo, Dan Zhang, Guang-Hui Wei
OBJECTIVE: To investigate the effect of outer membrane vesicles derived from Escherichia coli on proliferation, apoptosis and migration of human neuroblastoma SK-N-SH cells in vitro. METHODS: The outer membrane vesicles (OMVs) were obtained from wild-type Escherichia coli with ultracentrifugation method, and the morphology of the OMVs was observed by transmission electron microscopy and the vesicle diameter was determined using MALVERN ZEN3690. Human neuroblastoma SK-N-SH cells were treated with the OMVs at low (100 µg/mL), moderate (500 µg/mL) and high (1000 µg/mL) doses, and 24, 48 and 72 h later, the cell proliferation activity was detected with MTT assay...
March 20, 2018: Nan Fang Yi Ke da Xue Xue Bao, Journal of Southern Medical University
Danilo Donnarumma, Claudio Maestri, Pietro Ivan Giammarinaro, Luigi Capriotti, Erika Bartolini, Daniele Veggi, Roberto Petracca, Maria Scarselli, Nathalie Norais
Hydrogen Deuterium exchange (HDx) associated with Mass Spectrometry (MS) is emerging as a powerful tool to provide conformational information on membrane proteins. Unfortunately, as for X-ray diffraction and NMR, HDx performed on reconstituted in vitro systems might not always reflect the in vivo environment. Outer Membrane Vesicles naturally released by E. coli were used to carry out analysis of native OmpF through HDx-MS. A new protocol compatible with HDx analysis and avoiding hindrance from the lipid contents was set-up...
April 5, 2018: Journal of Proteome Research
María-Alexandra Cañas, María-José Fábrega, Rosa Giménez, Josefa Badia, Laura Baldomà
Gut microbiota plays a critical role in maintaining human intestinal homeostasis and host health. Bacterial extracellular vesicles are key players in bacteria-host communication, as they allow delivery of effector molecules into the host cells. Outer membrane vesicles (OMVs) released by Gram-negative bacteria carry many ligands of pattern recognition receptors that are key components of innate immunity. NOD1 and NOD2 cytosolic receptors specifically recognize peptidoglycans present within the bacterial cell wall...
2018: Frontiers in Microbiology
Gry Persson, Susanne E Pors, Ida C N Thøfner, Anders M Bojesen
Gallibacterium anatis is an opportunistic poultry pathogen belonging to the Pasteurellaceae family. It has been shown to cause oophoritis, salpingitis and peritonitis in hens, as well as being associated with reduced semen quality in cockerels. Widespread multidrug resistance and substantial antigenic variation among strains of Gallibacterium anatis is a major constraint to treatment with antimicrobials and prevention of infection by vaccination. Novel vaccine strategies targeting G. anatis are therefore necessary...
April 2018: Veterinary Microbiology
Alberto Rodriguez, Sebastian Escobar, Emilio Gomez, Victoria E Santos, Felix Garcia-Ochoa
The growth rate of four strains of Pseudomonas putida, KT2440, KT2442, KTH2 and KTH2 (pESOX3), under different fluid dynamic conditions has been studied. The cultures were conducted in a stirred tank bioreactor by changing the stirrer speed. Several process variables, such as biomass concentration, dissolved oxygen concentration, oxygen mass transfer rate and oxygen uptake rate, have been measured or calculated. Also cell viability was determined by viable colony counting in Petri dishes and culture samples were subjected into a transmission electron microscopy analysis, in order to describe the integrity of the individual cells...
March 31, 2018: Biotechnology Progress
Pankaj Deo, Seong H Chow, Iain D Hay, Oded Kleifeld, Adam Costin, Kirstin D Elgass, Jhih-Hang Jiang, Georg Ramm, Kipros Gabriel, Gordon Dougan, Trevor Lithgow, Eva Heinz, Thomas Naderer
Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhoea by evading innate immunity. Colonizing the mucosa of the reproductive tract depends on the bacterial outer membrane porin, PorB, which is essential for ion and nutrient uptake. PorB is also targeted to host mitochondria and regulates apoptosis pathways to promote infections. How PorB traffics from the outer membrane of N. gonorrhoeae to mitochondria and whether it modulates innate immune cells, such as macrophages, remains unclear. Here, we show that N...
March 2018: PLoS Pathogens
Si Won Kim, Seong Bin Park, Se Pyeong Im, Jung Seok Lee, Jae Wook Jung, Tae Won Gong, Jassy Mary S Lazarte, Jaesung Kim, Jong-Su Seo, Jong-Hwan Kim, Jong-Wook Song, Hyun Suk Jung, Gwang Joong Kim, Young Ju Lee, Suk-Kyung Lim, Tae Sung Jung
Outer membrane vesicles (OMVs) containing various bacterial compounds are released from mainly gram-negative bacteria. Secreted OMVs play important roles in the ability of a bacterium to defend itself, and thus contribute to the survival of bacteria in a community. In this study, we collected OMVs from β-lactam antibiotic-resistant Escherichia coli established by conjugation assay and the parental β-lactam antibiotic-susceptible strain, and performed comparative proteomic analysis to examine whether these OMVs carried β-lactam-resistant compounds...
March 29, 2018: Scientific Reports
Daria Augustyniak, Rafał Seredyński, Siobhán McClean, Justyna Roszkowiak, Bartosz Roszniowski, Darren L Smith, Zuzanna Drulis-Kawa, Paweł Mackiewicz
Moraxella catarrhalis is a common human respiratory tract pathogen. Its virulence factors associated with whole bacteria or outer membrane vesicles (OMVs) aid infection, colonization and may induce specific antibodies. To investigate pathogen-host interactions, we applied integrated bioinformatic and immunoproteomic (2D-electrophoresis, immunoblotting, LC-MS/MS) approaches. We showed that OMV proteins engaged exclusively in complement evasion and colonization strategies, but not those involved in iron transport and metabolism, are major targets for cross-reacting antibodies produced against phylogenetically divergent M...
March 21, 2018: Scientific Reports
Poorna Subramanian, Sahand Pirbadian, Mohamed Y El-Naggar, Grant J Jensen
Bacterial nanowires have garnered recent interest as a proposed extracellular electron transfer (EET) pathway that links the bacterial electron transport chain to solid-phase electron acceptors away from the cell. Recent studies showed that Shewanella oneidensis MR-1 produces outer membrane (OM) and periplasmic extensions that contain EET components and hinted at their possible role as bacterial nanowires. However, their fine structure and distribution of cytochrome electron carriers under native conditions remained unclear, making it difficult to evaluate the potential electron transport (ET) mechanism along OM extensions...
March 19, 2018: Proceedings of the National Academy of Sciences of the United States of America
Taylor C Stevenson, Colette Cywes-Bentley, Tyler D Moeller, Kevin B Weyant, David Putnam, Yung-Fu Chang, Bradley D Jones, Gerald B Pier, Matthew P DeLisa
Many microbial pathogens produce a β-(1→6)-linked poly- N -acetyl-d-glucosamine (PNAG) surface capsule, including bacterial, fungal, and protozoan cells. Broadly protective immune responses to this single conserved polysaccharide antigen in animals are possible but only when a deacetylated poly- N -acetyl-d-glucosamine (dPNAG; <30% acetate) glycoform is administered as a conjugate to a carrier protein. Unfortunately, conventional methods for natural extraction or chemical synthesis of dPNAG and its subsequent conjugation to protein carriers can be technically demanding and expensive...
March 19, 2018: Proceedings of the National Academy of Sciences of the United States of America
Sophie Brameyer, Laure Plener, Axel Müller, Andreas Klingl, Gerhard Wanner, Kirsten Jung
Many bacteria use extracellular signaling molecules to coordinate group behavior, a process referred to as quorum sensing (QS). However, some QS molecules are hydrophobic in character and are probably unable to diffuse across the bacterial cell envelope. How these molecules are disseminated between bacterial cells within a population is not yet fully understood. Here we show that the marine pathogen Vibrio harveyi packages the hydrophobic QS molecule CAI-1, a long-chain amino ketone, into outer membrane vesicles...
March 19, 2018: Journal of Bacteriology
Brianne J Lindsay, Michal M Bonar, Ian N Costas-Cancelas, Kristin Hunt, Alexander I Makarkov, Sabrina Chierzi, Connie M Krawczyk, Nathalie Landry, Brian J Ward, Isabelle Rouiller
Plant-made virus-like particle (VLP) vaccines that display wild-type influenza hemagglutinin (HA) are rapidly advancing through clinical trials. Produced by transient transfection of Nicotiana benthamiana, these novel vaccines are unusually immunogenic, eliciting both humoral and cellular responses. Here, we directly visualized VLPs bearing either HA trimers derived from strains A/California/7/2009 or A/Indonesia/5/05 using cryo-electron microscopy and determined the 3D organization of the VLPs using cryo-electron tomography...
March 14, 2018: Vaccine
Cátia F Gonçalves, Catarina C Pacheco, Paula Tamagnini, Paulo Oliveira
Cyanobacteria were the first organisms ever to perform oxygenic photosynthesis and still significantly contribute to primary production on a global scale. To assure the proper functioning of their primary metabolism and cell homeostasis, cyanobacteria must rely on efficient transport systems to cross their multilayered cell envelope. However, cyanobacterial secretion mechanisms remain largely unknown. Here, we report on the identification of 11 putative inner membrane translocase components of TolC-mediated secretion in the unicellular cyanobacterium Synechocystis sp...
March 9, 2018: Environmental Microbiology
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