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https://www.readbyqxmd.com/read/28752705/-bacterial-outer-membrane-vesicles-as-nano-carriers-to-study-immunological-activities
#1
Chen Qi, W U Min, Bai Hongzhen, Guo Zeling, Zhou Jun, Wang Qingqing, Tang Guping
Objective: To prepare a nano-carrier based on combining bacterial outer membrane vesicles (OMV) with three block polymer pluronic F127 (PEO100-PPO65-PEO100) (OMV-F127) and to investigate its immunological activity. Methods: Attenuated salmonella (sal) was cultivated. OMV were separated by centrifugal ultrafiltration or ultrasonication, and OMV-F127 was prepared by mechanical extrudation method. The protein contents and compositions were tested with BCA and SDS-PAGE; the morphology of OMV, F127 and OMV-F127 were observed with FM and TEM; the particle sizes and their zeta potential were determined with DLS...
March 25, 2017: Zhejiang da Xue Xue Bao. Yi Xue Ban, Journal of Zhejiang University. Medical Sciences
https://www.readbyqxmd.com/read/28741465/engineering-of-chimeric-protein-based-on-e-protein-domain-iii-of-tick-borne-encephalitis-virus-and-ompf-porin-of-yersinia-pseudotuberculosis
#2
Anna M Stenkova, Natalia S Chopenko, Ludmila A Davydova, Andrey N Mazeika, Evgeniya P Bystritskaya, Olga Y Portnyagina, Stanislav D Anastyuk, Dmitrii S Kulbatskii, Ekaterina N Lyukmanova, Dmitriy A Dolgikh, Eduard Y Kostetsky, Nina M Sanina
Tick-borne encephalitis poses a serious public health threat in the endemic regions. The disease treatment is restricted to symptomatic therapy, so great expectations are in the development of the prophylactic and therapeutic vaccines. The domain III of E protein of the tick-borne encephalitis virus is the main antigenic domain which includes virus-specific epitopes recognized by neutralizing antibodies. We have expressed, isolated and characterized the chimeric protein based on the fusion of domain III of E protein of the tick-borne encephalitis virus and bacterial porin OmpF from Yersinia pseudotuberculosis...
July 24, 2017: Protein and Peptide Letters
https://www.readbyqxmd.com/read/28730802/sensing-single-molecule-penetration-into-nanopores-pushing-the-time-resolution-to-the-diffusion-limit
#3
Igor V Bodrenko, Jiajun Wang, Samuele Salis, Mathias Winterhalter, Matteo Ceccarelli
To quantify small molecule penetration into and eventually permeation through nanopores, we applied an improved excess-noise analysis of the ion current fluctuation caused by entering molecules. The kinetic parameters of substrate entry and exit are derived from a two-state Markov model, analyzing the substrate concentration dependence of the average ion current and its variance. Including filter corrections allows one to detect the transition rates beyond the cutoff frequency, fc, of the instrumental ion-current filter...
July 28, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28728309/escherichia-coli-outer-membrane-protein-f-ompf-an-immunogenic-protein-induces-cross-reactive-antibodies-against-escherichia-coli-and-shigella
#4
Xiao Wang, Da Teng, Qingfeng Guan, Ruoyu Mao, Ya Hao, Xiumin Wang, Junhu Yao, Jianhua Wang
Diarrhea caused by pathogenic Escherichia coli (E. coli) is one of the most serious infectious diseases in humans and animals. Due to antibiotics resistance and the lack of efficient vaccine, more attention should be paid to find potential versatile vaccine candidates to prevent diseases. In this study, the sequence homology analysis indicated that OmpF from E. coli CVCC 1515 shares a high identity (90-100%) with about half of the E. coli (46.7%) and Shigella (52.8%) strains. Then the recombinant OmpF was supposed to be developed as a versatile vaccine to prevent E...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28726924/peculiarities-of-thermal-denaturation-of-ompf-porin-from-yersinia-ruckeri
#5
Olga D Novikova, Dmitry K Chistyulin, Valentina A Khomenko, Evgeny V Sidorin, Natalya Yu Kim, Nina M Sanina, Olga Yu Portnyagina, Tamara F Solov'eva, Vladimir N Uversky, Valery L Shnyrov
Irreversible denaturation of membrane proteins in detergent solutions is similar to unfolding of water-soluble multidomain proteins and represents a complex, multistage process. Pore-forming proteins of Gram-negative bacteria are heat-modifiable proteins, i.e., proteins altering their molecular forms (trimers or monomers), and accordingly, their electrophoretic mobilities depending upon denaturation conditions. There are still some contradictory data on the peculiarities of the conformational changes in the porin structure with temperature...
July 20, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28723607/production-of-recombinant-porin-from-y-pseudotuberculosis-in-a-water-soluble-form-for-pseudotuberculosis-diagnostics
#6
Vasily A Golotin, Olga Y Portnyagina, Natalia S Chopenko, Natalia Y Kim, Valery A Rasskazov, Olga D Novikova
OmpF porin from the outer membrane of Yersinia pseudotuberculosis was cloned into pET-40b(+) plasmid. Using E. coli Rosetta (DE3) strain, MX-medium, IPTG concentration of 0.2 mM and post-induction cultivation at 14 °C overnight allowed us to obtain a water-soluble form of the recombinant protein (rs-OmpF). Rs-OmpF was shown to have the ordered spatial structure at the levels of secondary and tertiary structure. Rs-OmpF was found to be effective as diagnostic antigen in ELISA for pseudotuberculosis diagnostics...
July 26, 2017: Biological Chemistry
https://www.readbyqxmd.com/read/28713335/a-novel-regulatory-cascade-involving-blur-ycgz-and-lon-controls-the-expression-of-escherichia-coli-ompf-porin
#7
Valérie Duval, Kimberly Foster, Jennifer Brewster, Stuart B Levy
In Escherichia coli, OmpF is an important outer membrane protein, which serves as a passive diffusion pore for small compounds including nutrients, antibiotics, and toxic compounds. OmpF expression responds to environmental changes such as temperature, osmolarity, nutrients availability, and toxic compounds via complex regulatory pathways involving transcriptional and post-transcriptional regulation. Our study identified a new regulatory cascade that controls the expression of OmpF porin. This pathway involves BluR, a transcriptional regulator repressing the expression of the ycgZ-ymgABC operon...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28650688/multidrug-resistant-enterobacteriaceae-in-lebanese-hospital-wastewater-implication-in-the-one-health-concept
#8
Ziad Daoud, Jina Farah, Elie Salem Sokhn, Khalil El Kfoury, Elias Dahdouh, Khalil Masri, Claude Afif, Roula M Abdel-Massih, Ghassan M Matar
Extended-spectrum beta-lactamases (ESBL) and carbapenemase-producing organisms pose severe problems for hospitalized patients. In the absence of efficient sanitation and sewage disposal, the risks for transmission of hospital organisms into the community are high. Our objectives were to study the occurrence and mechanisms of resistance of multidrug-resistant gram-negative bacilli in two Lebanese hospital sewage treatment plants. Wastewater samples were collected, filtered, and cultivated on MacConckey+cefotaxime agars...
June 26, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28412516/switching-between-nitrogen-and-glucose-limitation-unraveling-transcriptional-dynamics-in-escherichia-coli
#9
Michael Löffler, Joana Danica Simen, Jan Müller, Günter Jäger, Salaheddine Laghrami, Karin Schäferhoff, Andreas Freund, Ralf Takors
Transcriptional control under nitrogen and carbon-limitation conditions have been well analyzed for Escherichia coli. However, the transcriptional dynamics that underlie the shift in regulatory programs from nitrogen to carbon limitation is not well studied. In the present study, cells were cultivated at steady state under nitrogen (ammonia)-limited conditions then shifted to carbon (glucose) limitation to monitor changes in transcriptional dynamics. Nitrogen limitation was found to be dominated by sigma 54 (RpoN) and sigma 38 (RpoS), whereas the "housekeeping" sigma factor 70 (RpoD) and sigma 38 regulate cellular status under glucose limitation...
April 13, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28341438/engineering-a-novel-porin-ompgf-via-strand-replacement-from-computational-analysis-of-sequence-motif
#10
Meishan Lin, Ge Zhang, Monifa Fahie, Leslie K Morgan, Min Chen, Timothy A Keiderling, Linda J Kenney, Jie Liang
β-Barrelmembrane proteins (βMPs) form barrel-shaped pores in the outer membrane of Gram-negative bacteria, mitochondria, and chloroplasts. Because of the robustness of their barrel structures, βMPs have great potential as nanosensors for single-molecule detection. However, natural βMPs currently employed have inflexible biophysical properties and are limited in their pore geometry, hindering their applications in sensing molecules of different sizes and properties. Computational engineering has the promise to generate βMPs with desired properties...
July 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28337196/salmonella-typhi-porins-ompc-and-ompf-are-potent-adjuvants-for-t-dependent-and-t-independent-antigens
#11
Marisol Pérez-Toledo, Nuriban Valero-Pacheco, Rodolfo Pastelin-Palacios, Cristina Gil-Cruz, Christian Perez-Shibayama, Mario A Moreno-Eutimio, Ingeborg Becker, Sonia Mayra Pérez-Tapia, Lourdes Arriaga-Pizano, Adam F Cunningham, Armando Isibasi, Laura C Bonifaz, Constantino López-Macías
Several microbial components, such as bacterial DNA and flagellin, have been used as experimental vaccine adjuvants because of their inherent capacity to efficiently activate innate immune responses. Likewise, our previous work has shown that the major Salmonella Typhi (S. Typhi) outer membrane proteins OmpC and OmpF (porins) are highly immunogenic protective antigens that efficiently stimulate innate and adaptive immune responses in the absence of exogenous adjuvants. Moreover, S. Typhi porins induce the expression of costimulatory molecules on antigen-presenting cells through toll-like receptor canonical signaling pathways...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28315387/functional-role-of-ompf-and-ompc-porins-in-pathogenesis-of-avian-pathogenic-escherichia-coli
#12
Hassan M A Hejair, Yinchu Zhu, Jiale Ma, Yue Zhang, Zihao Pan, Wei Zhang, Huochun Yao
Avian pathogenic Escherichia coli is an important pathogen causes systemic infections in avian species and large economic losses in poultry industry worldwide. The functional role of porins during the infection and their mechanisms of interaction with host tissues for adhesion to and invasion are poorly understood. However, whether porins play a role in infection remains unclear. In this study we evaluated the potential of ompF and ompC outer membrane porins in the pathogenesis of avian pathogenic E. coli (APEC) strain TW-XM...
March 14, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28264855/structural-alteration-of-ompr-as-a-source-of-ertapenem-resistance-in-a-ctx-m-15-producing-escherichia-coli-o25b-h4-sequence-type-131-clinical-isolate
#13
Hervé Dupont, Pascaline Choinier, David Roche, Sandine Adiba, Megan Sookdeb, Catherine Branger, Erick Denamur, Hedi Mammeri
In this study, an ertapenem-nonsusceptible Escherichia coli isolate was investigated to determine the genetic basis for its carbapenem resistance phenotype. This clinical strain was recovered from a patient that received, 1 year previously, ertapenem to treat a cholangitis due to a carbapenem-susceptible extended-spectrum-β-lactamase (ESBL)-producing E. coli isolate. Whole-genome sequencing of these strains was performed using Illumina and single-molecule real-time sequencing technologies. It revealed that they belonged to the ST131 clonal group, had the predicted O25b:H4 serotype, and produced the CTX-M-15 and TEM-1 β-lactamases...
May 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28245829/improving-escherichia-coli-membrane-integrity-and-fatty-acid-production-by-expression-tuning-of-fadl-and-ompf
#14
Zaigao Tan, William Black, Jong Moon Yoon, Jacqueline V Shanks, Laura R Jarboe
BACKGROUND: Construction of microbial biocatalysts for the production of biorenewables at economically viable yields and titers is frequently hampered by product toxicity. Membrane damage is often deemed as the principal mechanism of this toxicity, particularly in regards to decreased membrane integrity. Previous studies have attempted to engineer the membrane with the goal of increasing membrane integrity. However, most of these works focused on engineering of phospholipids and efforts to identify membrane proteins that can be targeted to improve fatty acid production have been unsuccessful...
February 28, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28240914/general-method-to-determine-the-flux-of-charged-molecules-through-nanopores-applied-to-%C3%AE-lactamase-inhibitors-and-ompf
#15
Ishan Ghai, Alessandro Pira, Mariano Andrea Scorciapino, Igor Bodrenko, Lorraine Benier, Matteo Ceccarelli, Mathias Winterhalter, Richard Wagner
A major challenge in the discovery of the new antibiotics against Gram-negative bacteria is to achieve sufficiently fast permeation in order to avoid high doses causing toxic side effects. So far, suitable assays for quantifying the uptake of charged antibiotics into bacteria are lacking. We apply an electrophysiological zero-current assay using concentration gradients of β-lactamase inhibitors combined with single-channel conductance to quantify their flux rates through OmpF. Molecular dynamic simulations provide in addition details on the interactions between the nanopore wall and the charged solutes...
March 6, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28094462/orientation-of-the-ompf-porin-in-planar-lipid-bilayers
#16
Sandra A Ionescu, Sejeong Lee, Nicholas G Housden, Renata Kaminska, Colin Kleanthous, Hagan Bayley
The outer-membrane protein OmpF is an abundant trimeric general diffusion porin that plays a central role in the transport of antibiotics and colicins across the outer membrane of E. coli. Individual OmpF trimers in planar lipid bilayers (PLBs) show one of two current-voltage asymmetries, thus implying that insertion occurs with either the periplasmic or the extracellular end first. A method for establishing the orientation of OmpF in PLB was developed, based on targeted covalent modification with membrane-impermeant reagents of peripheral cysteine residues introduced near the periplasmic or the extracellular entrance...
March 16, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28076882/characterization-of-salmonella-typhi-ompc-and-ompf-porins-engineered-with-hiv-gp41-epitope-on-the-surface-loops
#17
Madhuranayaki Thulasingam, Subha Damodharan, Gopal Madhana Vigneshwari, Eswari P J Pandaranayaka, Luke Elizabeth Hanna, Ramakrishnan Usha, Sankaran Krishnaswamy
Porins form trimers in the outer membrane and help transport nutrients and waste products across the bacterial cell membrane. Porin loops are suitable candidates as display systems due to their high immunogenicity and presentation at the bacterial cell surface. In this study, Salmonella typhi porins (OmpC and OmpF) engineered with the Kennedy peptide from gp41 of HIV were characterised. The chimeric OmpC carrying the Kennedy peptide in loop7 did not trimerise, whereas the chimeric OmpF with the epitope in loop5 formed trimers and also was recognised by the antibodies in the HIV patient serum...
April 2017: Proteins
https://www.readbyqxmd.com/read/28072422/the-fitness-costs-and-trade-off-shapes-associated-with-the-exclusion-of-nine-antibiotics-by-ompf-porin-channels
#18
Katherine Phan, Thomas Ferenci
The trade-off relationship between antibiotic exclusion and nutrient access across the Gram-negative outer membrane is determined by structural constraints in porin channels. The precise nutritional cost of exclusion is unknown for different antibiotics, as are the shapes of the nutrition-susceptibility trade-off. Using a library of 10 engineered isogenic Escherichia coli strains with structural modifications of OmpF porin expressed at a constant level, susceptibilities were measured for nine antibiotics and the nutritional fitness costs estimated by competitions in chemostats...
June 2017: ISME Journal
https://www.readbyqxmd.com/read/28054667/yersinia-pestis-halotolerance-illuminates-plague-reservoirs
#19
Maliya Alia Malek, Idir Bitam, Anthony Levasseur, Jérôme Terras, Jean Gaudart, Said Azza, Christophe Flaudrops, Catherine Robert, Didier Raoult, Michel Drancourt
The plague agent Yersinia pestis persists for years in the soil. Two millennia after swiping over Europe and North Africa, plague established permanent foci in North Africa but not in neighboring Europe. Mapping human plague foci reported in North Africa for 70 years indicated a significant location at <3 kilometers from the Mediterranean seashore or the edge of salted lakes named chotts. In Algeria, culturing 352 environmental specimens naturally containing 0.5 to 70 g/L NaCl yielded one Y. pestis Orientalis biotype isolate in a 40 g/L NaCl chott soil specimen...
January 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/27965634/structural-elucidation-and-molecular-docking-of-a-novel-antibiotic-compound-from-cyanobacterium-nostoc-sp-mgl001
#20
Niveshika, Ekta Verma, Arun K Mishra, Angad K Singh, Vinay K Singh
Cyanobacteria are rich source of array of bioactive compounds. The present study reports a novel antibacterial bioactive compound purified from cyanobacterium Nostoc sp. MGL001 using various chromatographic techniques viz. thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Further characterization was done using electrospray ionization mass spectroscopy (ESIMS) and nuclear magnetic resonance (NMR) and predicted structure of bioactive compound was 9-Ethyliminomethyl-12-(morpholin - 4 - ylmethoxy) -5, 8, 13, 16-tetraaza-hexacene - 2, 3 dicarboxylic acid (EMTAHDCA)...
2016: Frontiers in Microbiology
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