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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
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
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
Xavier Sáez-Llorens, Johnny Beltran-Rodriguez, Jose M Novoa Pizarro, Ilhem Mensi, Pavitra Keshavan, Daniela Toneatto
This open-label, multicenter extension study (NCT01210885) assessed persistence of Neisseria meningitidis serogroups ABCWY antibodies 4 years after primary vaccination. Adolescents and young adults who previously received 2 doses of MenABCWY+OMV (Group III), 1 dose of MenACWY-CRM (Group VI), or newly-recruited vaccine-naïve participants (Group VII) were administered 1 (Group III) or 2 doses (Groups VI and VII) of MenABCWY+OMV, 1 month apart. Immunogenicity was assessed by human serum bactericidal assay (hSBA)...
March 30, 2018: Human Vaccines & Immunotherapeutics
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
Nadia Marascio, Grazia Pavia, Isabella Romeo, Carmine Talarico, Sebastiano Di Salvo, Mariaconcetta Reale, Vito Marano, Giorgio Settimo Barreca, Fernanda Fabiani, Nicola Perrotti, Massimo De Siena, Francesca Giancotti, Tiziana Gravina, Stefano Alcaro, Anna Artese, Carlo Torti, Maria Carla Liberto, Alfredo Focà
We report a real-life 3D therapy failure in a patient treated with ombitasvir (OMV)/paritaprevir/ritonavir and dasabuvir without ribavirin (3D-R). He had therapy failure at week 12 after the end of treatment. We detected resistance-associated substitutions (RASs) plus polymorphisms on NS3, NS5A and NS5B target regions by population sequencing (15% cut-off) at baseline, at relapse and during follow-up. About this, NS5A RASs generally persist longer than resistances in the other target genes and may impact treatment outcome...
March 25, 2018: Journal of Medical Virology
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
A W Dretler, N G Rouphael, D S Stephens
The control of meningitis, meningococcemia and other infections caused by Neisseria meningitidis is a significant global health challenge. Substantial progress has occurred in the last twenty years in meningococcal vaccine development and global implementation. Meningococcal protein-polysaccharide conjugate vaccines to serogroups A, C, W, and Y (modeled after the Haemophilus influenzae b conjugate vaccines) provide better duration of protection and immunologic memory, and overcome weak immune responses in infants and young children and hypo-responsive to repeated vaccine doses seen with polysaccharide vaccines...
March 15, 2018: Human Vaccines & Immunotherapeutics
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
Victor Zarantonello, Thiago P Silva, Natália P Noyma, Juliana P Gamalier, Mariana M Mello, Marcelo M Marinho, Rossana C N Melo
Secretion of membrane-limited vesicles, collectively termed extracellular vesicles (EVs), is an important biological process of both eukaryotic and prokaryotic cells. This process has been observed in bacteria, but remains to be better characterized at high resolution in cyanobacteria. In the present work, we address the release of EVs by Cylindrospermopsis raciborskii (CYRF-01), a filamentous bloom-forming cyanobacterium, exposed to environmental stressors. First, non-axenic cultures of C. raciborskii (CYRF-01) were exposed to ultraviolet radiation (UVA + UVB) over a 6 h period, which is known to induce structural damage to this species...
2018: Frontiers in Microbiology
Nafiseh Noroozi, Seyed Latif Mousavi Gargari, Shahram Nazarian, Samaneh Sarvary, Razieh Rezaei Adriani
Objectives: Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrheal disease in humans, particularly in children under 5 years and travelers in developing countries.To our knowledge, no vaccine is licensed yet to protect against ETEC infection. Like many Gram-negative pathogens, ETEC can secrete outer membrane vesicles (OMVs). These structures contain various immunogenic virulence proteins such as LT and therefore can be used as vaccine candidates. In this study we attempted to isolate the OMVs of ETEC cultivated at different temperatures and evaluate their immunogenicity and protective efficacy in a murine model of infection...
March 2018: Iranian Journal of Basic Medical Sciences
Giorgio Gabarrini, Laura M Palma Medina, Tim Stobernack, Rianne C Prins, Marines du Teil Espina, Jeroen Kuipers, Monika A Chlebowicz, John W A Rossen, Arie Jan van Winkelhoff, Jan Maarten van Dijl
The oral pathogen Porphyromonas gingivalis is one of the major periodontal agents and it has been recently hailed as a potential cause of the autoimmune disease rheumatoid arthritis. In particular, the peptidylarginine deiminase enzyme of P. gingivalis (PPAD) has been implicated in the citrullination of certain host proteins and the subsequent appearance of antibodies against citrullinated proteins, which might play a role in the etiology of rheumatoid arthritis. The aim of this study was to investigate the extracellular localization of PPAD in a large panel of clinical P...
January 1, 2018: Virulence
Lingzhi Zhang, Zhiwei Jiang, Shan Fang, Yajun Huang, Dahai Yang, Qiyao Wang, Yuanxing Zhang, Qin Liu
Many bacterial pathogens inject effectors directly into host cells to target a variety of host cellular processes and promote bacterial dissemination and survival. Identifying the bacterial effectors and elucidating their functions are central to understanding the molecular pathogenesis of these pathogens. Edwardsiella piscicida is a pathogen with a wide host range, and very few of its effectors have been identified to date. Here, based on the genes significantly regulated by macrophage infection, we identified 25 intracellular translocation-positive candidate effectors, including all five previously reported effectors, namely EseG, EseJ, EseH, EseK, and EvpP...
2018: Frontiers in Cellular and Infection Microbiology
Janine Habier, Patrick May, Anna Heintz-Buschart, Anubrata Ghosal, Anke K Wienecke-Baldacchino, Esther N M Nolte-'t Hoen, Paul Wilmes, Joëlle V Fritz
Outer membrane vesicles (OMVs) are released by commensal as well as pathogenic Gram-negative bacteria. These vesicles contain numerous bacterial components, such as proteins, peptidoglycans, lipopolysaccharides, DNA, and RNA. To examine if OMV-associated RNA molecules are bacterial degradation products and/or are functionally active, it is necessary to extract RNA from pure OMVs for subsequent analysis. Therefore, we describe here an isolation method of ultrapure OMVs and the subsequent extraction of RNA and basic steps of RNA-Seq analysis...
2018: Methods in Molecular Biology
Lan Gu, Ran Meng, Yiting Tang, Kai Zhao, Fang Liang, Rui Zhang, Qianqian Xue, Fangping Chen, Xianzhong Xiao, Huadong Wang, Haichao Wang, Timothy R Billiar, Ben Lu
Outer membrane vesicles (OMVs), released by variety of bacteria, are membrane-enclosed entities enriched in microbial components, toxins and virulent factors. OMVs could deliver lipopolysaccharide (LPS) into the cytosol of host cells and subsequently activate caspase-11, which critically orchestrates immune responses and mediates septic shock. Though it is known that caspase-11 is activated by intracellular LPS, how OMVs deliver LPS into the cytosol remains largely unknown. Here we show that the activation of toll like receptor 4 (TLR4), a LPS receptor on the cytoplasmic membrane, licenses macrophages to transport LPS from OMVs into the cytosol through TIR domain-containing adaptor-inducing interferon-β (TRIF)...
February 16, 2018: Shock
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