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https://www.readbyqxmd.com/read/28414919/functional-characterization-of-an-n-terminally-truncated-mitochondrial-porin-expressed-in-i-neurospora-crassa-i
#1
Sabbir Rahman Shuvo, Uliana Kovaltchouk, Abdullah Zubaer, Ayush Kumar, William A T Summers, Lynda J Donald, George Hausner, Deborah A Court
Mitochondrial porin, which forms voltage-dependent anion-selective channels (VDAC) in the outer membrane, can be folded into a 19 β-stranded barrel. The N-terminus of the protein is external to the barrel, and contains α-helical structure. Targeted modifications of the N‑terminal region have been assessed in artificial membranes, leading to different models for gating <i>in vitro</i>. However, the i<i>n vivo</i> requirements for gating and the N-terminal segment of porin are less well-understood...
April 17, 2017: Canadian Journal of Microbiology
https://www.readbyqxmd.com/read/28413638/serologic-testing-of-a-panel-of-five-antibodies-in-inflammatory-bowel-diseases-diagnostic-value-and-correlation-with-disease-phenotype
#2
Zhi-Zhi Wang, Ke Shi, Jie Peng
The aim of the present study was to evaluate the diagnostic value of five serological antibodies, perinuclear antineutrophil cytoplasmic antibody (pANCA), anti-Saccharomyces cerevisiae antibodies [ASCA; ASCA-immunoglobulin (IgG)and ASCA-IgA], Escherichia coli outer membrane porin C antibody (anti-OmpC) and CBir1 flagellin antibody for detection in inflammatory bowel diseases. Whether the antibody status correlated with the disease phenotype was also evaluated. Sera from 71 patients with Crohn's disease (CD), 41 patients with ulcerative colitis (UC), 78 patients with other gastrointestinal diseases and 31 healthy control subjects were investigated...
April 2017: Biomedical Reports
https://www.readbyqxmd.com/read/28412516/switching-between-nitrogen-and-glucose-limitation-unraveling-transcriptional-dynamics-in-escherichia-coli
#3
Michael Löffler, Joana Danica Simen, Jan Müller, Günter Jäger, Salaheddine Laghrami, Karin Schäferhoff, Andreas Freund, Ralf Takors, 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 12, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28402509/identification-of-is1r-and-is10r-elements-inserted-into-ompk36-porin-gene-of-two-multidrug-resistant-klebsiella-pneumoniae-hospital-strains
#4
Anastasia I Lev, Evgeny I Astashkin, Rima Z Shaikhutdinova, Mikhail E Platonov, Nikolay N Kartsev, Nikolay V Volozhantsev, Olga N Ershova, Edward A Svetoch, Nadezhda K Fursova
Hospital Klebsiella pneumoniae strains (n = 196) were collected in 2012-16 from the patients of Moscow neurosurgical intensive care unit. K. pneumoniae strains were multi drug resistant (MDR) and carried beta-lactamase genes blaSHV (97.4% strains), blaCTX-M (84.7%), blaTEM (56.1%), blaOXA-48-like (49.0%), and blaNDM-1 (one strain), class 1 integrons (43.4% strains) and porin protein ompK36 gene (100% strains). The ompK36 porin protein gene disruption by IS-elements and OmpK36 production loss in two strains were detected in this study...
April 11, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28400767/the-periplasmic-chaperone-network-of-campylobacter-jejuni-evidence-that-salc-cj1289-and-ppid-cj0694-are-involved-in-maintaining-outer-membrane-integrity
#5
Aidan J Taylor, Shadi A I Zakai, David J Kelly
The outer membrane (OM) of Gram-negative pathogenic bacteria is a key structure in host-pathogen interactions that contains a plethora of proteins, performing a range of functions including adhesion, nutrient uptake, export of effectors and interaction with innate and adaptive components of the immune system. In addition, the OM can exclude drugs and thus contribute to antimicrobial resistance. The OM of the food-borne pathogen Campylobacter jejuni contains porins, adhesins and other virulence factors that must be specifically localized to this membrane, but the protein sorting mechanisms involved are only partially understood...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28398866/genome-wide-survey-of-genes-under-positive-selection-in-avian-pathogenic-escherichia-coli-strains
#6
Thaís Cabrera Galvão Rojas, Francisco Pereira Lobo, Jorge Augusto Hongo, Renato Vicentini, Renu Verma, Renato Pariz Maluta, Wanderley Dias da Silveira
The ability to obtain bacterial genomes from the same host has allowed for comparative studies that help in the understanding of the molecular evolution of specific pathotypes. Avian pathogenic Escherichia coli (APEC) is a group of extraintestinal strains responsible for causing colibacillosis in birds. APEC is also suggested to possess a role as a zoonotic agent. Despite its importance, APEC pathogenesis still has several cryptic pathogenic processes that need to be better understood. In this work, a genome-wide survey of eight APEC strains for genes with evidence of recombination revealed that ∼14% of the homologous groups evaluated present signs of recombination...
February 17, 2017: Foodborne Pathogens and Disease
https://www.readbyqxmd.com/read/28396547/resistance-to-ceftazidime-avibactam-in-klebsiella-pneumoniae-due-to-porin-mutations-and-the-increased-expression-of-kpc-3
#7
Romney M Humphries, Peera Hemarajata
We reported the first clinical case of a ceftazidime-avibactam resistant KPC-3-producing Klebsiella pneumoniae (1), from a patient with no prior history of ceftazidime-avibactam therapy.….
April 10, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28392440/emergence-of-colistin-resistance-in-pseudomonas-aeruginosa-st235-clone-in-south-korea
#8
Yu Mi Wi, Ji-Young Choi, Ji-Young Lee, Cheol-In Kang, Doo Ryeon Chung, Kyong Ran Peck, Jae-Hoon Song, Kwan Soo Ko
In this study, the prevalence and characteristics of metallo-β-lactamase (MBL)-producing Pseudomonas aeruginosa isolates in South Korea were investigated. Among 215 P. aeruginosa isolates collected from eight hospitals, 77 (35.8%) and 72 (33.5%) were resistant to imipenem and meropenem, respectively. Of the 77 imipenem-resistant isolates, MBL genes were identified in 34 isolates (blaIMP-6 in 33 isolates and blaVIM-2 in 1 isolate). All of the MBL-producing isolates belonged to a globally prevailing genotype, sequence type 235 (ST235), and all of the IMP-6-producing isolates showed a deletion of nucleotide 209 of the porin gene oprD...
April 6, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28389664/the-tlr2-binding-neisserial-porin-porb-enhances-antigen-presenting-cell-trafficking-and-cross-presentation
#9
Michael L Reiser, Munir M Mosaheb, Christina Lisk, Andrew Platt, Lee M Wetzler
TOLL-like receptor (TLR) ligands activate both innate and adaptive immune cells, while modulating the cellular immune response. The outer membrane protein (OMP) from Neisseria meninigitidis, PorB, is a naturally occurring TLR2 ligand and functions as an adjuvant. Here, we demonstrate that PorB increases the level of OVA in the endo-/lysosomal cellular compartment of BMDCs, increases antigen presenting cell (APC) trafficking to draining lymph nodes, and enhances antigen cross-presentation. PorB is capable of mounting an antigen specific T cell response by efficiently stimulating antigen cross-presentation in vivo and in vitro assessed by BMDC OT-I cocultivation assays...
April 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28384185/evaluation-of-a-modified-meropenem-hydrolysis-assay-on-a-large-cohort-of-kpc-and-vim-carbapenemase-producing-enterobacteriaceae
#10
Adriana Calderaro, Mirko Buttrini, Maddalena Piergianni, Sara Montecchini, Monica Martinelli, Silvia Covan, Giovanna Piccolo, Maria Cristina Medici, Maria Cristina Arcangeletti, Carlo Chezzi, Flora De Conto
Carbapenem-resistant Enterobacteriaceae (CRE) have spread globally and represent a serious and growing threat to public health. The introduction of rapid and sensitive methods for the detection of carbapenemase-producing bacteria is of increasing importance. The carbapenemase production can be detected using non-molecular methods (such as the modified Hodge test, the synergy test, the Carba NP test and the antibiotic hydrolysis assays) and DNA-based methods. In this study, we propose a modified version of a previously described meropenem hydrolysis assay (MHA) by MALDI-TOF MS for the phenotypic detection in 2h of carbapenemase-producing Enterobacteriaceae...
2017: PloS One
https://www.readbyqxmd.com/read/28373967/defining-the-roles-of-the-cation-diffusion-facilitators-in-fe-2-zn-2-homeostasis-and-establishment-of-their-participation-in-virulence-in-pseudomonas-aeruginosa
#11
Agostina Salusso, Daniel Raimunda
Transporters of the cation diffusion facilitator (CDF) family form dimers that export transition metals from the cytosol. The opportunistic pathogen Pseudomonas aeruginosa encodes three homologous CDF genes, czcD (PA0397), aitP (PA1297), and yiiP (PA3963). The three proteins are required for virulence in a plant host model. Disruption of the aitP gene leads to higher Fe(2+) and Co(2+) sensitivity together with an intracellular accumulation of these ions and to a decreased survival in presence of H2O2. Strains lacking czcD and yiiP showed low Zn(2+) sensitivity...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28373273/appropriate-regulation-of-the-%C3%AF-e-dependent-envelope-stress-response-is-necessary-to-maintain-cell-envelope-integrity-and-stationary-phase-survival-in-escherichia-coli
#12
Hervé Nicoloff, Saumya Gopalkrishnan, Sarah E Ades
The alternative sigma factor σ(E) is a key component of the Escherichia coli response to cell envelope stress and is required for viability even in the absence of stress. σ(E) activity increases during entry into stationary phase suggesting an important role for σ(E) when nutrients are limiting. Elevated σ(E) activity has been proposed to activate a pathway leading to lysis of non-culturable cells that accumulate during early stationary phase. To better understand σ(E)-directed cell lysis and the role of σ(E) in stationary phase, we investigated the effects of elevated σ(E) activity in cultures grown for ten days...
April 3, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28348979/biology-of-acinetobacter-baumannii-pathogenesis-antibiotic-resistance-mechanisms-and-prospective-treatment-options
#13
REVIEW
Chang-Ro Lee, Jung Hun Lee, Moonhee Park, Kwang Seung Park, Il Kwon Bae, Young Bae Kim, Chang-Jun Cha, Byeong Chul Jeong, Sang Hee Lee
Acinetobacter baumannii is undoubtedly one of the most successful pathogens responsible for hospital-acquired nosocomial infections in the modern healthcare system. Due to the prevalence of infections and outbreaks caused by multi-drug resistant A. baumannii, few antibiotics are effective for treating infections caused by this pathogen. To overcome this problem, knowledge of the pathogenesis and antibiotic resistance mechanisms of A. baumannii is important. In this review, we summarize current studies on the virulence factors that contribute to A...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28348410/a-pseudomonas-t6ss-effector-recruits-pqs-containing-outer-membrane-vesicles-for-iron-acquisition
#14
Jinshui Lin, Weipeng Zhang, Juanli Cheng, Xu Yang, Kaixiang Zhu, Yao Wang, Gehong Wei, Pei-Yuan Qian, Zhao-Qing Luo, Xihui Shen
Iron sequestration by host proteins contributes to the defence against bacterial pathogens, which need iron for their metabolism and virulence. A Pseudomonas aeruginosa mutant lacking all three known iron acquisition systems retains the ability to grow in media containing iron chelators, suggesting the presence of additional pathways involved in iron uptake. Here we screen P. aeruginosa mutants defective in growth in iron-depleted media and find that gene PA2374, proximal to the type VI secretion system H3 (H3-T6SS), functions synergistically with known iron acquisition systems...
March 28, 2017: Nature Communications
https://www.readbyqxmd.com/read/28341438/engineering-a-novel-porin-ompgf-via-strand-replacement-from-computational-analysis-of-sequence-motif
#15
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...
March 21, 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
#16
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/28336135/high-prevalence-of-non-clonal-imipenem-nonsusceptible-enterobacter-spp-isolates-in-korea-and-their-association-with-porin-down-regulation
#17
Ji-Young Lee, Yoon-Kyoung Hong, Haejeong Lee, Kwan Soo Ko
We investigated the prevalence and clonal distribution of imipenem-nonsusceptible Enterobacter clinical isolates from hospitals in Korea and the contributions of various mechanisms to imipenem nonsusceptibility. The in vitro antimicrobial susceptibility to imipenem of 357 non-duplicated Enterobacter isolates obtained from eight geographically distant tertiary care hospitals in Korea was evaluated. Imipenem-nonsusceptible Enterobacter isolates were genotyped. Additionally, β-lactamase genes were screened using PCR, and the expression of efflux pump and porin genes was investigated using quantitative RT-PCR...
January 2017: Diagnostic Microbiology and Infectious Disease
https://www.readbyqxmd.com/read/28334028/providencia-stuartii-form-biofilms-and-floating-communities-of-cells-that-display-high-resistance-to-environmental-insults
#18
Mariam El Khatib, Que-Tien Tran, Chady Nasrallah, Julie Lopes, Jean-Michel Bolla, Michel Vivaudou, Jean-Marie Pagès, Jacques-Philippe Colletier
Biofilms are organized communities of bacterial cells that are responsible for the majority of human chronic bacterial infections. Providencia stuartii is a Gram-negative biofilm-forming bacterium involved in high incidence of urinary tract infections in catheterized patients. Yet, the structuration of these biofilms, and their resistance to environmental insults remain poorly understood. Here, we report on planktonic cell growth and biofilm formation by P. stuartii, in conditions that mimic its most common pathophysiological habitat in humans, i...
2017: PloS One
https://www.readbyqxmd.com/read/28333323/high-ceftazidime-hydrolysis-activity-and-porin-ompk35-deficiency-contribute-to-the-decreased-susceptibility-to-ceftazidime-avibactam-in-kpc-producing-klebsiella-pneumoniae
#19
Zhen Shen, Baixing Ding, Meiping Ye, Peng Wang, Yingmin Bi, Shi Wu, Xiaogang Xu, Qinglan Guo, Minggui Wang
Objectives: To investigate mechanisms for the decreased susceptibility to ceftazidime/avibactam in KPC-producing Klebsiella pneumoniae (KPC-KP). Methods: A total of 24 isolates, 8 each with ceftazidime/avibactam MICs of 4-8, 1-2 and ≤0.5 mg/L, were randomly selected from 214 clinical isolates of KPC-KP, and the β-lactamase hydrolysis activity and porin expression profiles were determined. Plasmid profile and relative expression and copy number of the bla KPC gene were also analysed...
March 15, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28333319/wck-4234-a-novel-diazabicyclooctane-potentiating-carbapenems-against-enterobacteriaceae-pseudomonas-and-acinetobacter-with-class-a-c-and-d-%C3%AE-lactamases
#20
Shazad Mushtaq, Anna Vickers, Neil Woodford, David M Livermore
Background: Several diazabicyclooctanes (DBOs) are under development as inhibitors of class A and C β-lactamases. Inhibition of OXA (class D) carbapenemases is variable, with those of Acinetobacter spp. remaining notably resistant. We describe a novel DBO, WCK 4234 (Wockhardt), with distinctive activity against OXA carbapenemases. Methods: MICs of imipenem and meropenem were determined by CLSI agar dilution with WCK 4234 added at 4 or 8 mg/L. Test organisms were clinical Enterobacteriaceae, Acinetobacter baumannii and Pseudomonas aeruginosa with carbapenemases or carbapenem resistance via porin loss plus AmpC or ESBL activity...
February 16, 2017: Journal of Antimicrobial Chemotherapy
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