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https://www.readbyqxmd.com/read/27901137/energy-transduction-and-signal-averaging-of-fluctuating-electric-fields-by-a-single-protein-ion-channel
#1
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...
November 30, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27887765/activity-of-ceftazidime-avibactam-against-multidrug-resistance-enterobacteriaceae-expressing-combined-mechanisms-of-resistance
#2
Inmaculada López-Hernández, Noemí Alonso, Marta Fernández-Martínez, Laura Zamorano, Alba Rivera, Antonio Oliver, M Carmen Conejo, Luis Martínez-Martínez, Ferrán Navarro, Alvaro Pascual
INTRODUCTION: Antimicrobial resistance in Enterobacteriaceae is increasing worldwide and is making treating infections caused by multidrug-resistant Enterobacteriaceae a challenge. The use of β-lactam agents is compromised by microorganisms harboring extended-spectrum β-lactamases (ESBLs) and other mechanisms of resistance. Avibactam is a non β-lactam agent that inhibits clinically relevant β-lactamases, such as ESBL and AmpC. The ceftazidime-avibactam combination (CAZ-AVI) was recently approved for use in certain complicated infections, and may provide a therapeutic alternative for infections caused by these microorganisms...
November 22, 2016: Enfermedades Infecciosas y Microbiología Clínica
https://www.readbyqxmd.com/read/27887202/serological-markers-in-diagnosis-of-pediatric-inflammatory-bowel-disease-and-as-predictors-for-early-tumor-necrosis-factor-blocker-therapy
#3
Christine Olbjørn, Milada Cvancarova Småstuen, Espen Thiis-Evensen, Britt Nakstad, Morten Harald Vatn, Gøri Perminow
OBJECTIVE: To describe the prevalence of serological markers in newly diagnosed treatment-naïve pediatric inflammatory bowel disease (IBD), their utility in differentiating Crohn's disease (CD), ulcerative colitis (UC) and symptomatic non-IBD patients and whether serological markers are associated with early TNF blocker treatment. MATERIAL AND METHODS: Ninety-six children and adolescents <18 years, 58 with IBD and 38 symptomatic non-IBD controls were included...
November 25, 2016: Scandinavian Journal of Gastroenterology
https://www.readbyqxmd.com/read/27881168/loss-of-porin-function-in-dopaminergic-neurons-of-drosophila-is-suppressed-by-buffy
#4
P Githure M'Angale, Brian E Staveley
BACKGROUND: Mitochondrial porin, also known as the voltage-dependent anion channel (VDAC), is a multi-functional channel protein that shuttles metabolites between the mitochondria and the cytosol and implicated in cellular life and death decisions. The inhibition of porin under the control of neuronal Ddc-Gal4 result in short lifespan and in an age-dependent loss in locomotor function, phenotypes that are strongly associated with Drosophila models of Parkinson disease. METHODS: Loss of porin function was achieved through exploitation of RNA interference while derivative lines were generated by homologous recombination and tested by PCR...
November 24, 2016: Journal of Biomedical Science
https://www.readbyqxmd.com/read/27857712/some-like-it-hot-heat-resistance-of-escherichia-coli-in-food
#5
REVIEW
Hui Li, Michael Gänzle
Heat treatment and cooking are common interventions for reducing the numbers of vegetative cells and eliminating pathogenic microorganisms in food. Current cooking method requires the internal temperature of beef patties to reach 71°C. However, some pathogenic Escherichia coli such as the beef isolate E. coli AW 1.7 are extremely heat resistant, questioning its inactivation by current heat interventions in beef processing. To optimize the conditions of heat treatment for effective decontaminations of pathogenic E...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27854150/response-of-escherichia-coli-to-prolonged-berberine-exposure
#6
Nilay Budeyri Gokgoz, Fatma Gizem Avci, Kubra Karaosmanoglu Yoneten, Begum Alaybeyoglu, Elif Ozkirimli, Nihat Alpagu Sayar, Dilek Kazan, Berna Sariyar Akbulut
Berberine is a plant-derived alkaloid possessing antimicrobial activity; unfortunately, its efflux through multidrug resistance pumps reduces its efficacy. Cellular life span of Escherichia coli is generally shorter with prolonged berberine exposure; nevertheless, about 30% of the cells still remain robust following this treatment. To elucidate its mechanism of action and to identify proteins that could be involved in development of antimicrobial resistance, protein profiles of E. coli cells treated with berberine for 4...
November 17, 2016: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/27836448/multilocus-amplicon-sequencing-of-pseudomonas-aeruginosa-cystic-fibrosis-airways-isolates-collected-prior-to-and-after-early-antipseudomonal-chemotherapy
#7
Sebastian Fischer, Leonie Greipel, Jens Klockgether, Marie Dorda, Lutz Wiehlmann, Nina Cramer, Burkhard Tümmler
BACKGROUND: Early antimicrobial chemotherapy can prevent or at least delay chronic cystic fibrosis (CF) airways infections with Pseudomonas aeruginosa. METHODS: During a 10-year study period P. aeruginosa was detected for the first time in 54 CF patients regularly seen at the CF centre Hannover. Amplicon sequencing of 34 loci of the P. aeruginosa core genome was performed in baseline and post-treatment isolates of the 15 CF patients who had remained P. aeruginosa - positive after the first round of antipseudomonal chemotherapy...
November 8, 2016: Journal of Cystic Fibrosis: Official Journal of the European Cystic Fibrosis Society
https://www.readbyqxmd.com/read/27834373/in-vivo-protein-interaction-network-analysis-reveals-porin-localized-antibiotic-inactivation-in-acinetobacter-baumannii-strain-ab5075
#8
Xia Wu, Juan D Chavez, Devin K Schweppe, Chunxiang Zheng, Chad R Weisbrod, Jimmy K Eng, Ananya Murali, Samuel A Lee, Elizabeth Ramage, Larry A Gallagher, Hemantha D Kulasekara, Mauna E Edrozo, Cassandra N Kamischke, Mitchell J Brittnacher, Samuel I Miller, Pradeep K Singh, Colin Manoil, James E Bruce
The nosocomial pathogen Acinetobacter baumannii is a frequent cause of hospital-acquired infections worldwide and is a challenge for treatment due to its evolved resistance to antibiotics, including carbapenems. Here, to gain insight on A. baumannii antibiotic resistance mechanisms, we analyse the protein interaction network of a multidrug-resistant A. baumannii clinical strain (AB5075). Using in vivo chemical cross-linking and mass spectrometry, we identify 2,068 non-redundant cross-linked peptide pairs containing 245 intra- and 398 inter-molecular interactions...
November 11, 2016: Nature Communications
https://www.readbyqxmd.com/read/27817033/modulation-of-the-reactivity-of-multiheme-cytochromes-by-site-directed-mutagenesis-moving-towards-the-optimization-of-microbial-electrochemical-technologies
#9
Alexandra S Alves, Nazua L Costa, Ming Tien, Ricardo O Louro, Catarina M Paquete
Dissimilatory metal-reducing bacteria perform extracellular electron transfer, a metabolic trait that is at the core of a wide range of biotechnological applications. To better understand how these microorganisms transfer electrons from their metabolism to an extracellular electron acceptor, it is necessary to characterize in detail the key players in this process, the multiheme c-type cytochromes. Shewanella oneidensis MR-1 is a model organism for studying extracellular electron transfer, where the heme protein referred to as small tetraheme cytochrome is one of the most abundant multiheme cytochromes found in the periplasmic space of this bacterium...
November 5, 2016: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/27817013/novel-efficient-promoter-of-the-mitochondrial-porin-voltage-dependent-anion-channel-vdac-in-the-genome-of-the-yarrowia-lipolytica-yeast
#10
F F Kulanbaewa, V Yu Sekova, E P Isakova, Y I Deryabina, A V Nikolaev
This article presents the characteristics of the highly inducible promoter of the gene encoding the mitochondrial porin, the voltage-dependent anion channel (VDAC). This promoter is recommended for use in new genetic constructs both in basic research for assessing the adaptive strategy of lower eukaryotes under adverse conditions and in designing new highly competitive transformants producing economically important compounds (proteins, lipids, and organic acids) on its basis.
September 2016: Doklady. Biochemistry and Biophysics
https://www.readbyqxmd.com/read/27799202/acquisition-of-carbapenem-resistance-by-plasmid-encoded-ampc-expressing-escherichia-coli
#11
Ria van Boxtel, Agnes A Wattel, Jesús Arenas, Wil H F Goessens, Jan Tommassen
Although AmpC β-lactamases can barely or not degrade carbapenems, they can sequester them and prevent them from reaching their targets. Thus, carbapenem resistance in Escherichia coli and other Enterobacteriaceae can result from production of AmpC and simultaneous reduction of antibiotic influx into the periplasm by mutations in the porin genes. Here, we investigated the route and genetic mechanisms of acquiring carbapenem resistance in a clinical E. coli isolate carrying blaCMY-2 on a plasmid by selecting for mutants that are resistant to increasing concentrations of meropenem...
October 31, 2016: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/27797865/the-enhanced-immune-responses-induced-by-salmonella-enteritidis-ghosts-loaded-with-neisseria-gonorrhoeae-porb-against-salmonella-in-mice
#12
Hongmei Jiao, Hui Yang, Dan Zhao, Li He, Jin Chen, Guocai Li
Humans health has been seriously endangered by highly prevalent salmonellosis and multidrug resistant Salmonella strains. Current vaccines suffer from variable immune-protective effects, so more effective ones are in need to control Salmonella infection : Bacterial ghosts have been produced by the expression of lysis gene E from bacteriophage PhiX174 and can be filled with considerable exogenous substances such as DNA or drugs as a novel platform. In this study, Salmonella enteritidis (SE) ghosts were developed and loaded with Neisseria gonorrhoeae porin B (porB) to construct a novel inactive vaccine...
October 18, 2016: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/27796471/deletion-of-degq-gene-enhances-outer-membrane-vesicle-production-of-shewanella-oneidensis-cells
#13
Yoshihiro Ojima, Thivagaran Mohanadas, Kosei Kitamura, Shota Nunogami, Reiki Yajima, Masahito Taya
Shewanella oneidensis is a Gram-negative facultative anaerobe that can use a wide variety of terminal electron acceptors for anaerobic respiration. In this study, S. oneidensis degQ gene, encoding a putative periplasmic serine protease, was cloned and expressed. The activity of purified DegQ was inhibited by diisopropyl fluorophosphate, a typical serine protease-specific inhibitor, indicating that DegQ is a serine protease. In-frame deletion and subsequent complementation of the degQ were carried out to examine the effect of envelope stress on the production of outer membrane vesicles (OMVs)...
October 31, 2016: Archives of Microbiology
https://www.readbyqxmd.com/read/27794611/cyanobacterial-surface-display-system-mediates-engineered-interspecies-and-abiotic-binding
#14
Derek T Fedeson, Daniel C Ducat
Cyanobacteria are uniquely suited for development of sustainable bioproduction platforms, but are currently underutilized in scaled applications in part due to a lack of genetic tools. Here, we develop a surface display system in the cyanobacterial model Synechococcus elongatus PCC7942 via expression of modified versions of the outer membrane porin, SomA. Importantly, we demonstrate accessibility of heterologous functional groups on the recombinant porin to the external environment in living cells. We show that this requires the removal of occluding factors that include lipopolysaccharides and a putative surface layer protein...
October 30, 2016: ACS Synthetic Biology
https://www.readbyqxmd.com/read/27792711/-purification-of-salmonella-typhimurium-ompd-porin-induces-long-term-high-levels-of-antibodies-implications-on-the-development-of-vaccines-against-non-typhoid-salmonella
#15
Marisol Pérez-Toledo, Paola A Martínez-Amador, Rodolfo Pastelin-Palacios, Armando Isibasi, Adam F Cunningham, Constantino López-Macías
In the present work, we report, for the first time, on the purification of the Salmonella Typhimurium OmpD porin. We assessed the integrity and purity of the protein and evaluated the immunogenicity of the protein and its ability to induce antibody without exogenous adjuvant. We observed that 10 μg OmpD induced high antibody levels of IgM and IgG, which were maintained for more than 260 days after immunization. Immunization with OmpD induced multiple IgG antibody isotypes including IgG1, IgG2a, IgG2b, and IgG3 subclasses...
October 2016: Gaceta Médica de México
https://www.readbyqxmd.com/read/27788691/outbreak-of-kpc-3-producing-st15-and-st348-klebsiella-pneumoniae-in-a-portuguese-hospital
#16
D Vubil, R Figueiredo, T Reis, C Canha, L Boaventura, G J DA Silva
To date, only a few sporadic cases of infections due to Klebsiella pneumoniae carbapenemase (KPC) producers have been reported in Portugal. Here, we report for the first time an outbreak of K. pneumoniae KPC-3 producers in a tertiary-care hospital during 2013. Twenty-seven ertapenem-resistant K. pneumoniae were identified in patients at a tertiary-care hospital during 2013 isolated predominantly from urine (48·1%) and blood (25·9%) cultures. All isolates were highly resistant to β-lactam antibiotics and most showed intermediate resistance to imipenem...
October 28, 2016: Epidemiology and Infection
https://www.readbyqxmd.com/read/27773766/affinity-purification-of-bacterial-outer-membrane-vesicles-omvs-utilizing-a-his-tag-mutant
#17
Nathan J Alves, Kendrick B Turner, Kyle A DiVito, Michael A Daniele, Scott A Walper
To facilitate the rapid purification of bacterial outer membrane vesicles (OMVs), we developed two plasmid constructs that utilize a truncated, transmembrane protein to present an exterior histidine repeat sequence. We chose OmpA, a highly abundant porin protein, as the protein scaffold and utilized the lac promoter to allow for inducible control of the epitope-presenting construct. OMVs containing mutant OmpA-His6 were purified directly from Escherichia coli culture media on an immobilized metal affinity chromatography (IMAC) Ni-NTA resin...
October 20, 2016: Research in Microbiology
https://www.readbyqxmd.com/read/27771745/stress-responses-of-acinetobacter-strain-y-during-phenol-degradation
#18
Johnson Lin
Quantification of gene expression of Acinetobacter strain Y under 1000 mg/l of phenol was investigated using qPCR and proteomic analyses. The results show that Acinetobacter strain Y utilized 100 % of phenol within 18 h of exposure. The results of qPCR and proteomic analyses demonstrate a sequential expression of phenol-degrading genes of Acinetobacter strain Y via the ortho-pathway followed by the β-ketoadipate pathway. Many stress-responsive proteins such as chaperones, chaperonins, porins and the enzymes involved in the signal transduction pathway were upregulated especially in the early stage...
October 22, 2016: Archives of Microbiology
https://www.readbyqxmd.com/read/27737551/fluorescent-trimethoprim-conjugate-probes-to-assess-drug-accumulation-in-wild-type-and-mutant-escherichia-coli
#19
Wanida Phetsang, Ruby Pelingon, Mark S Butler, Sanjaya Kc, Miranda E Pitt, Geraldine Kaeslin, Matthew A Cooper, Mark A T Blaskovich
Reduced susceptibility to antimicrobials in Gram-negative bacteria may result from multiple resistance mechanisms, including increased efflux pump activity or reduced porin protein expression. Up-regulation of the efflux pump system is closely associated with multidrug resistance (MDR). To help investigate the role of efflux pumps on compound accumulation, a fluorescence-based assay was developed using fluorescent derivatives of trimethoprim (TMP), a broad-spectrum synthetic antibiotic that inhibits an intracellular target, dihydrofolate reductase (DHFR)...
October 14, 2016: ACS Infectious Diseases
https://www.readbyqxmd.com/read/27729524/design-and-characterization-of-a-nanopore-coupled-polymerase-for-single-molecule-dna-sequencing-by-synthesis-on-an-electrode-array
#20
P Benjamin Stranges, Mirkó Palla, Sergey Kalachikov, Jeff Nivala, Michael Dorwart, Andrew Trans, Shiv Kumar, Mintu Porel, Minchen Chien, Chuanjuan Tao, Irina Morozova, Zengmin Li, Shundi Shi, Aman Aberra, Cleoma Arnold, Alexander Yang, Anne Aguirre, Eric T Harada, Daniel Korenblum, James Pollard, Ashwini Bhat, Dmitriy Gremyachinskiy, Arek Bibillo, Roger Chen, Randy Davis, James J Russo, Carl W Fuller, Stefan Roever, Jingyue Ju, George M Church
Scalable, high-throughput DNA sequencing is a prerequisite for precision medicine and biomedical research. Recently, we presented a nanopore-based sequencing-by-synthesis (Nanopore-SBS) approach, which used a set of nucleotides with polymer tags that allow discrimination of the nucleotides in a biological nanopore. Here, we designed and covalently coupled a DNA polymerase to an α-hemolysin (αHL) heptamer using the SpyCatcher/SpyTag conjugation approach. These porin-polymerase conjugates were inserted into lipid bilayers on a complementary metal oxide semiconductor (CMOS)-based electrode array for high-throughput electrical recording of DNA synthesis...
November 1, 2016: Proceedings of the National Academy of Sciences of the United States of America
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