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https://www.readbyqxmd.com/read/28932951/structure-elucidation-and-in-silico-docking-studies-of-a-novel-furopyrimidine-antibiotics-synthesized-by-endolithic-bacterium-actinomadura-sp-al2
#1
Kaushik Bhattacharjee, Shakti Kumar, Narasinga Rao Palepu, Pradeep Kumar Patra, Kollipara Mohan Rao, Santa Ram Joshi
On screening of endolithic actinobacteria from a granite rock sample of Meghalaya for antibacterial compound, a novel antibacterial compound CCp1 was isolated from the fermentation broth of Actinomadura sp. AL2. On purification of the compound based on chromatographic techniques followed by characterization with FT-IR, UV-visible, (1)H NMR, (13)C NMR and mass spectrometry, the molecular formula of the compound was generated as C20H17N3O2, a furopyrimidine derivative. In vitro antibacterial activity of the compound was evaluated against both Gram positive and negative bacteria by agar well diffusion assay...
September 20, 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28930428/ion-transport-in-confined-geometries-below-the-nanoscale-access-resistance-dominates-protein-channel-conductance-in-diluted-solutions
#2
Antonio Alcaraz, M Lidón López, María Queralt-Martín, Vicente M Aguilella
Synthetic nanopores and mesoscopic protein channels have common traits like the importance of electrostatic interactions between the permeating ions and the nanochannel. Ion transport at the nanoscale occurs under confinement conditions so that the usual assumptions made in microfluidics are challenged, among others, by interfacial effects such as access resistance (AR). Here, we show that a sound interpretation of electrophysiological measurements in terms of channel ion selective properties requires the consideration of interfacial effects, up to the point that they dominate protein channel conductance in diluted solutions...
September 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/28890516/molecular-characterization-of-non-carbapenemase-producing-escherichia-coli-clinical-isolates-with-reduced-carbapenem-susceptibility-from-a-thai-university-hospital
#3
Sawitree Nuramrum, Aroonwadee Chanawong, Kamonwan Lunha, Aroonlug Lulitanond, Arunnee Sangka, Chotechana Wilailuckana, Sunpetch Angkititrakul, Nicha Charoensri, Lumyai Wonglakorn, Prajuab Chaimanee, Ploenchan Chetchotisakd
Twelve non-replicate carbapenemase-negative ertapenem-non-susceptible (CNENS) Escherichia coli isolates from a Thai university hospital between 2010 and 2014 were characterized and compared with two carbapenemase-producing E. coli isolates from the same hospital. Eight unique PFGE patterns were obtained. All produced CTX-M-15 β-lactamase and two isolates co-expressed either CMY-2 cephalosporinase or increased efflux pump. Amino acid sequence analysis revealed that OmpF defect (seven isolates) due to mutations generating premature proteins or an IS1 insertion was more prevalent than in OmpC (no truncated proteins found)...
September 11, 2017: Japanese Journal of Infectious Diseases
https://www.readbyqxmd.com/read/28888366/lipopolysaccharides-promote-binding-and-unfolding-of-the-antibacterial-colicin-e3-rrnase-domain
#4
Allan Mills, Franck Duong
Nuclease colicins are antibacterial proteins produced by certain strains of E. coli to reduce competition from rival strains. These colicins are generally organized with an N-terminal transport (T)-domain, a central receptor binding (R)-domain, and a C-terminal cytotoxic nuclease domain. These colicins are always produced in complex with an inhibitory immunity protein, which dissociates prior entrance of the cytotoxic domain in the target cell. How exactly colicins traverse the cell envelope is not understood, yet this knowledge is important for the design of new antibacterial therapies...
September 6, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28887208/proteomic-comparison-of-three-clinical-diarrhoeagenic-drug-resistant-escherichia-coli-isolates-grown-on-chromagar%C3%A2-stec-media
#5
John Bosco Kalule, Suereta Fortuin, Bridget Calder, Lourens Robberts, Karen H Keddy, Andrew Nel, Shaun Garnett, Mark Nicol, Digby F Warner, Nelson C Soares, Jonathan M Blackburn
Shiga-toxin-producing Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) are key diarrhoea-causing foodborne pathogens. We used proteomics to characterize the virulence and antimicrobial resistance protein profiles of three clinical pathogenic E. coli isolates (two EPEC [one resistant to ciprofloxacin] and one STEC) cultured on CHROMagar™STEC solid media after minimal laboratory passage. We identified 4767 unique peptides from 1630 protein group across all three clinical E. coli strains...
September 5, 2017: Journal of Proteomics
https://www.readbyqxmd.com/read/28874380/the-global-regulatory-protein-crp-controls-multifactorial-fluoroquinolone-susceptibility-in-salmonella-enterica-serovar-typhimurium
#6
Stefani C Kary, Joshua R K Yoneda, Stephen C Olshefsky, Laura A Stewart, Steven B West, Andrew D S Cameron
Fluoroquinolone antibiotics are prescribed for the treatment of Salmonella enterica infections, but resistance to this family of antibiotics is growing. Here we report that loss of the global regulatory protein, CRP, or its allosteric effector, cAMP, reduces susceptibility to fluoroquinolones. A Δcrp mutation was synergistic with the primary fluoroquinolone resistance allele gyrA83, thus can contribute to clinically-relevant resistance. Decreased susceptibility to fluoroquinolones could be partly explained by decreased expression of the outer membrane porin genes ompA and ompF with a concomitant increase in the expression of the ciprofloxacin-resistance efflux pump gene acrB in Δcrp cells...
September 5, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28818426/investigation-of-the-escherichia-coli-membrane-transporters-involved-in-the-secretion-of-d-lactate-based-oligomers-by-loss-of-function-screening
#7
Camila Utsunomia, Chiaki Hori, Ken'ichiro Matsumoto, Seiichi Taguchi
d-Lactate (LA)-based oligomers (D-LAOs) are unusual oligoesters consisting of d-LA and d-3-hydroxybutyrate that are produced and secreted by engineered Escherichia coli grown on glucose. The cells heterologously express LA-polymerizing polyhydroxyalkanoate synthase and monomer-supplying enzymes. In this study, we attempted to identify the D-LAO secretion route in E. coli, which is thought to be mediated by intrinsic membrane proteins. To this end, a loss-of-function screening of D-LAO secretion was carried out using 209 single-gene membrane protein deletants, which are involved in the transport of organic compounds...
August 14, 2017: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/28752705/-bacterial-outer-membrane-vesicles-as-nano-carriers-to-study-immunological-activities
#8
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
#9
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
#10
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...
August 25, 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
#11
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
#12
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...
August 22, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28723607/production-of-recombinant-porin-from-y-pseudotuberculosis-in-a-water-soluble-form-for-pseudotuberculosis-diagnostics
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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