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https://www.readbyqxmd.com/read/28076882/characterization-of-salmonella-typhi-ompc-and-ompf-porins-engineered-with-hiv-gp41-epitope-on-the-surface-loops
#1
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...
January 11, 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
#2
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...
January 10, 2017: ISME Journal
https://www.readbyqxmd.com/read/28054667/yersinia-pestis-halotolerance-illuminates-plague-reservoirs
#3
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
#4
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
https://www.readbyqxmd.com/read/27915254/ompf-of-pectobacterium-carotovorum-subsp-carotovorum-pcc3-is-required-for-carocin-d-sensitivity
#5
Jeong-A Lim, Jisoo Hong, Jonguk Kim, Sunggi Heu, Eunjung Roh
Carocin D is a bacteriocin produced by Pectobacterium carotovorum subsp. carotovorum Pcc21. Carocin D inhibits the growth of P carotovorum subsp. carotovorum and closely related strains. Pectobacterium carotovorum subsp. carotovorum is a causative bacterium for soft rot disease and leads to severe economic losses. Bacteriocins recognize and interact with a specific membrane protein of target bacteria as a receptor. To identify the receptor responsible for carocin D recognition, mutants that underwent a phenotypic change from carocin D sensitivity to carocin D insensitivity were screened...
December 2016: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/27901137/energy-transduction-and-signal-averaging-of-fluctuating-electric-fields-by-a-single-protein-ion-channel
#6
C Verdia-Baguena, V Gomez, J Cervera, P Ramirez, S Mafe
We demonstrate the electrical rectification and signal averaging of fluctuating signals using a biological nanostructure in aqueous solution: a single protein ion channel inserted in the lipid bilayer characteristic of cell membranes. The conversion of oscillating, zero time-average potentials into directional currents permits charging of a load capacitor to significant steady-state voltages within a few minutes in the case of the outer membrane porin F (OmpF) protein, a bacterial channel of Escherichia coli...
December 21, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27884940/ecological-speciation-of-bacteriophage-lambda-in-allopatry-and-sympatry
#7
Justin R Meyer, Devin T Dobias, Sarah J Medina, Lisa Servilio, Animesh Gupta, Richard E Lenski
Understanding the conditions that allow speciation to occur is difficult because most research has focused on either long-lived organisms or asexual microorganisms. We propagated bacteriophage λ, a virus with rapid generations and frequent recombination, on two Escherichia coli host genotypes that expressed either the LamB or OmpF receptor. When supplied with either single host (allopatry), phage λ improved its binding to the available receptor while losing its ability to use the alternative. When evolving on both hosts together (sympatry), the viruses split into two lineages with divergent receptor preferences...
December 9, 2016: Science
https://www.readbyqxmd.com/read/27723824/cdia-effectors-from-uropathogenic-escherichia-coli-use-heterotrimeric-osmoporins-as-receptors-to-recognize-target-bacteria
#8
Christina M Beck, Julia L E Willett, David A Cunningham, Jeff J Kim, David A Low, Christopher S Hayes
Many Gram-negative bacterial pathogens express contact-dependent growth inhibition (CDI) systems that promote cell-cell interaction. CDI+ bacteria express surface CdiA effector proteins, which transfer their C-terminal toxin domains into susceptible target cells upon binding to specific receptors. CDI+ cells also produce immunity proteins that neutralize the toxin domains delivered from neighboring siblings. Here, we show that CdiAEC536 from uropathogenic Escherichia coli 536 (EC536) uses OmpC and OmpF as receptors to recognize target bacteria...
October 2016: PLoS Pathogens
https://www.readbyqxmd.com/read/27716985/d-tyrosine-affects-aggregation-behavior-of-pantoea-agglomerans
#9
Jing Yang, Jiajia Yu, Jing Jiang, Chen Liang, Yongjun Feng
D-amino acids have been proved to disassemble biofilms by disassociating the matrix. Pantoea agglomerans is characterized by the formation of another kind of multicellular structure called symplasmata, which also remains the ability to form biofilms. In this study, a rice diazotrophic endophyte P. agglomerans YS19 was selected as a model strain to explore the effects of D-amino acids on these two kinds of cell aggregate structures. It was discovered that D-tyrosine disassociates biofilm, yet promotes symplasmata formation...
September 22, 2016: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/27693650/momp-from-campylobacter-jejuni-is-a-trimer-of-18-stranded-%C3%AE-barrel-monomers-with-a-ca-2-ion-bound-at-the-constriction-zone
#10
Luana G M Ferrara, Gregor D Wallat, Lucile Moynié, Naresh N Dhanasekar, Soumeya Aliouane, Silvia Acosta-Gutiérrez, Jean-Marie Pagès, Jean-Michel Bolla, Mathias Winterhalter, Matteo Ceccarelli, James H Naismith
The Gram-negative organism Campylobacter jejuni is the major cause of food poisoning. Unlike Escherichia coli, which has two major porins, OmpC and OmpF, C. jejuni has one, termed major outer membrane protein (MOMP) through which nutrients and antibiotics transit. We report the 2.1-Å crystal structure of C. jejuni MOMP expressed in E. coli and a lower resolution but otherwise identical structure purified directly from C. jejuni. The 2.1-Å resolution structure of recombinant MOMP showed that although the protein has timeric arrangement similar to OmpC, it is an 18-stranded, not 16-stranded, β-barrel...
September 30, 2016: Journal of Molecular Biology
https://www.readbyqxmd.com/read/27683370/host-coevolution-alters-the-adaptive-landscape-of-a-virus
#11
Alita R Burmeister, Richard E Lenski, Justin R Meyer
The origin of new and complex structures and functions is fundamental for shaping the diversity of life. Such key innovations are rare because they require multiple interacting changes. We sought to understand how the adaptive landscape led to an innovation whereby bacteriophage λ evolved the new ability to exploit a receptor, OmpF, on Escherichia coli cells. Previous work showed that this ability evolved repeatedly, despite requiring four mutations in one virus gene. Here, we examine how this innovation evolved by studying six intermediate genotypes of λ isolated during independent transitions to exploit OmpF and comparing them to their ancestor...
September 28, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27645385/klebsiella-pneumoniae-major-porins-ompk35-and-ompk36-allow-more-efficient-diffusion-of-%C3%AE-lactams-than-their-escherichia-coli-homologs-ompf-and-ompc
#12
Etsuko Sugawara, Seiji Kojima, Hiroshi Nikaido
: Klebsiella pneumoniae, one of the most important nosocomial pathogens, is becoming a major problem in health care because of its resistance to multiple antibiotics, including cephalosporins of the latest generation and, more recently, even carbapenems. This is largely due to the spread of plasmid-encoded extended-spectrum β-lactamases. However, antimicrobial agents must first penetrate the outer membrane barrier in order to reach their targets, and hydrophilic and charged β-lactams presumably diffuse through the porin channels...
December 1, 2016: Journal of Bacteriology
https://www.readbyqxmd.com/read/27593697/effect-of-natural-polymorphism-on-structure-and-function-of-the-yersinia-pestis-outer-membrane-porin-f-ompf-protein-a-computational-study
#13
Hiba Shaban, Insing Na, Angelina A Kislichkina, Svetlana V Dentovskaya, Andrey P Anisimov, Vladimir N Uversky
The Yersinia pestis outer membrane porin F (OmpF) is a transmembrane protein located in the outer membrane of this Gram-negative bacterium which is the causative agent of plague, where it plays a significant role in controlling the selective permeability of the membrane. The amino acid sequences of OmpF proteins from 48 Y. pestis strains representing all currently available phylogenetic groups of this Gram-negative bacterium were recently deduced. Comparison of these amino acid sequences revealed that the OmpF can be present in four isoforms, the pestis-pestis type, and the pestis-microtus types I, II, and III...
September 3, 2016: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/27578962/molecular-evolution-of-the-yersinia-major-outer-membrane-protein-c-ompc
#14
Anna M Stenkova, Evgeniya P Bystritskaya, Konstantin V Guzev, Alexander V Rakin, Marina P Isaeva
The genus Yersinia includes species with a wide range of eukaryotic hosts (from fish, insects, and plants to mammals and humans). One of the major outer membrane proteins, the porin OmpC, is preferentially expressed in the host gut, where osmotic pressure, temperature, and the concentrations of nutrients and toxic products are relatively high. We consider here the molecular evolution and phylogeny of Yersinia ompC. The maximum likelihood gene tree reflects the macroevolution processes occurring within the genus Yersinia...
2016: Evolutionary Bioinformatics Online
https://www.readbyqxmd.com/read/27578754/new-insights-into-the-formation-of-viable-but-nonculturable-escherichia-coli-o157-h7-induced-by-high-pressure-co2
#15
Feng Zhao, Yongtao Wang, Haoran An, Yanling Hao, Xiaosong Hu, Xiaojun Liao
UNLABELLED: The formation of viable but nonculturable (VBNC) Escherichia coli O157:H7 induced by high-pressure CO2 (HPCD) was investigated using RNA sequencing (RNA-Seq) transcriptomics and isobaric tag for relative and absolute quantitation (iTRAQ) proteomic methods. The analyses revealed that 97 genes and 56 proteins were significantly changed upon VBNC state entry. Genes and proteins related to membrane transport, central metabolisms, DNA replication, and cell division were mainly downregulated in the VBNC cells...
2016: MBio
https://www.readbyqxmd.com/read/27547605/reconstitution-of-the-membrane-protein-ompf-into-biomimetic-block-copolymer-phospholipid-hybrid-membranes
#16
Matthias Bieligmeyer, Franjo Artukovic, Stephan Nussberger, Thomas Hirth, Thomas Schiestel, Michaela Müller
Structure and function of many transmembrane proteins are affected by their environment. In this respect, reconstitution of a membrane protein into a biomimetic polymer membrane can alter its function. To overcome this problem we used membranes formed by poly(1,4-isoprene-block-ethylene oxide) block copolymers blended with 1,2-diphytanoyl-sn-glycero-3-phosphocholine. By reconstituting the outer membrane protein OmpF from Escherichia coli into these membranes, we demonstrate functionality of this protein in biomimetic lipopolymer membranes, independent of the molecular weight of the block copolymers...
2016: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/27533297/selenium-nanoparticles-incorporated-into-titania-nanotubes-inhibit-bacterial-growth-and-macrophage-proliferation
#17
Wenwen Liu, Negar H Golshan, Xuliang Deng, Daniel J Hickey, Katherine Zeimer, Hongyi Li, Thomas J Webster
Since implants often fail due to infection and uncontrolled inflammatory responses, we designed an in vitro study to investigate the antibacterial and anti-inflammatory properties of titanium dioxide nanotubes (TNTs) incorporated with selenium nanoparticles (SeNPs). Selenium incorporation was achieved by the reaction of sodium selenite (Na2SeO3) with glutathione (GSH) under a vacuum in the presence of TNTs. Two types of bacteria and macrophages were cultured on the samples to determine their respective antibacterial and anti-inflammatory properties...
August 25, 2016: Nanoscale
https://www.readbyqxmd.com/read/27464527/effects-of-extreme-ph-on-ionic-transport-through-protein-nanopores-the-role-of-ion-diffusion-and-charge-exclusion
#18
María Queralt-Martín, Carlos Peiró-González, Marcel Aguilella-Arzo, Antonio Alcaraz
We combine electrophysiological experiments with the structure-based Poisson-Nernst-Planck 3D calculations to investigate the transport properties of the bacterial porin OmpF under large pH gradients and particularly low salt concentrations. We show that under extreme pH conditions protons and hydroxyls contribute decisively to the overall measured current, challenging the traditional interpretation of some electrokinetic parameters such as channel selectivity and rectification properties. We analyze with unprecedented detail the two intertwined factors ruling the ionic permeation through the channel, namely the differences between cation and anion mobilities and the electrostatic exclusion due to the interaction between permeating ions and channel ionizable residues...
August 3, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27439713/unexpected-properties-of-srna-promoters-allow-feedback-control-via-regulation-of-a-two-component-system
#19
Anaïs Brosse, Anna Korobeinikova, Susan Gottesman, Maude Guillier
Two-component systems (TCS) and small regulatory RNAs (sRNAs) are both widespread regulators of gene expression in bacteria. TCS are in most cases transcriptional regulators. A large class of sRNAs act as post-transcriptional regulators of gene expression that modulate the translation and/or stability of target-mRNAs. Many connections have been recently unraveled between these two types of regulators, resulting in mixed regulatory circuits with poorly characterized properties. This study focuses on the negative feedback circuit that exists between the EnvZ-OmpR TCS and the OmrA/B sRNAs...
November 16, 2016: Nucleic Acids Research
https://www.readbyqxmd.com/read/27342557/yersinia-enterocolitica-specific-infection-by-bacteriophages-tg1-and-%C3%AF-r1-rt-is-dependent-on-temperature-regulated-expression-of-the-phage-host-receptor-ompf
#20
Carlos G Leon-Velarde, Lotta Happonen, Maria Pajunen, Katarzyna Leskinen, Andrew M Kropinski, Laura Mattinen, Monika Rajtor, Joanna Zur, Darren Smith, Shu Chen, Ayesha Nawaz, Roger P Johnson, Joseph A Odumeru, Mansel W Griffiths, Mikael Skurnik
UNLABELLED: Bacteriophages present huge potential both as a resource for developing novel tools for bacterial diagnostics and for use in phage therapy. This potential is also valid for bacteriophages specific for Yersinia enterocolitica To increase our knowledge of Y. enterocolitica-specific phages, we characterized two novel yersiniophages. The genomes of the bacteriophages vB_YenM_TG1 (TG1) and vB_YenM_ϕR1-RT (ϕR1-RT), isolated from pig manure in Canada and from sewage in Finland, consist of linear double-stranded DNA of 162,101 and 168,809 bp, respectively...
September 1, 2016: Applied and Environmental Microbiology
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