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Porins

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https://www.readbyqxmd.com/read/29145596/a-crispr-cas9-based-exploration-into-the-elusive-mechanism-for-lactate-export-in-saccharomyces-cerevisiae
#1
Robert Mans, Else-Jasmijn Hassing, Melanie Wijsman, Annabel Giezekamp, Jack T Pronk, Jean-Marc Daran, Antonius J A van Maris
CRISPR/Cas9-based genome editing allows rapid, simultaneous modification of multiple genetic loci in Saccharomyces cerevisiae. Here, this technique was used in a functional analysis study aimed at identifying the hitherto unknown mechanism of lactate export in this yeast. First, an S. cerevisiae strain was constructed with deletions in 25 genes encoding transport proteins, including the complete aqua(glycero)porin family and all known carboxylic-acid transporters. The 25-deletion strain was then transformed with an expression cassette for Lactobacillus casei lactate dehydrogenase (LcLDH)...
November 14, 2017: FEMS Yeast Research
https://www.readbyqxmd.com/read/29136861/quality-by-design-approach-in-the-development-of-an-ultra-high-performance-liquid-chromatography-method-for-bexsero-meningococcal-group-b-vaccine
#2
Luca Nompari, Serena Orlandini, Benedetta Pasquini, Cristiana Campa, Michele Rovini, Massimo Del Bubba, Sandra Furlanetto
Bexsero is the first approved vaccine for active immunization of individuals from 2 months of age and older to prevent invasive disease caused by Neisseria meningitidis serogroup B. The active components of the vaccine are Neisseria Heparin Binding Antigen, factor H binding protein, Neisseria adhesin A, produced in Escherichia coli cells by recombinant DNA technology, and Outer Membrane Vesicles (expressing Porin A and Porin B), produced by fermentation of Neisseria meningitidis strain NZ98/254. All the Bexsero active components are adsorbed on aluminum hydroxide and the unadsorbed antigens content is a product critical quality attribute...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29133912/the-multiple-antibiotic-resistance-operon-of-enteric-bacteria-controls-dna-repair-and-outer-membrane-integrity
#3
Prateek Sharma, James R J Haycocks, Alistair D Middlemiss, Rachel A Kettles, Laura E Sellars, Vito Ricci, Laura J V Piddock, David C Grainger
The multiple antibiotic resistance (mar) operon of Escherichia coli is a paradigm for chromosomally encoded antibiotic resistance in enteric bacteria. The locus is recognised for its ability to modulate efflux pump and porin expression via two encoded transcription factors, MarR and MarA. Here we map binding of these regulators across the E. coli genome and identify an extensive mar regulon. Most notably, MarA activates expression of genes required for DNA repair and lipid trafficking. Consequently, the mar locus reduces quinolone-induced DNA damage and the ability of tetracyclines to traverse the outer membrane...
November 13, 2017: Nature Communications
https://www.readbyqxmd.com/read/29127147/igg1-is-required-for-optimal-protection-after-immunization-with-the-purified-porin-ompd-from-salmonella-typhimurium
#4
Yang Zhang, Coral Dominguez-Medina, Nicola J Cumley, Jennifer N Heath, Sarah J Essex, Saeeda Bobat, Anna Schager, Margaret Goodall, Sven Kracker, Christopher D Buckley, Robin C May, Robert A Kingsley, Calman A MacLennan, Constantino López-Macías, Adam F Cunningham, Kai-Michael Toellner
In mice, the IgG subclass induced after Ag encounter can reflect the nature of the Ag. Th2 Ags such as alum-precipitated proteins and helminths induce IgG1, whereas Th1 Ags, such as Salmonella Typhimurium, predominantly induce IgG2a. The contribution of different IgG isotypes to protection against bacteria such as S. Typhimurium is unclear, although as IgG2a is induced by natural infection, it is assumed this isotype is important. Previously, we have shown that purified S. Typhimurium porins including outer membrane protein OmpD, which induce both IgG1 and IgG2a in mice, provide protection to S...
November 10, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/29099689/identification-of-novel-small-rnas-in-burkholderia-cenocepacia-kc-01-expressed-under-iron-limitation-and-oxidative-stress-conditions
#5
Suparna Ghosh, Chetna Dureja, Indu Khatri, Srikrishna Subramanian, Saumya Raychaudhuri, Sagarmoy Ghosh
Small RNA (sRNA)-mediated regulation of gene expression is a major tool to understand bacterial responses to environmental changes. In particular, pathogenic bacteria employ sRNAs to adapt to the host environment and establish infection. Members of the Burkholderia cepacia complex, normally present in soil microbiota, cause nosocomial lung infection especially in hospitalized cystic fibrosis patients. We sequenced the draft genome of Burkholderia cenocepacia KC-01, isolated from the coastal saline soil, and identified several potential sRNAs in silico...
November 3, 2017: Microbiology
https://www.readbyqxmd.com/read/29091420/gene-mediated-chemical-communication-in-synthetic-protocell-communities
#6
T-Y Dora Tang, Dario Cecchi, Giorgio Fracasso, Davide Accardi, Angelique Coutable, Sheref S Mansy, Adam W Perriman, John Leslie Ross Anderson, Stephen Mann
A gene-directed chemical communication pathway between synthetic protocell signaling transmitters (lipid vesicles) and receivers (proteinosomes) was designed, built and tested using a bottom-up modular approach comprising small molecule transcriptional control, cell-free gene expression, porin-directed efflux, substrate signaling, and enzyme cascade-mediated processing.
November 1, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/29089426/synergy-between-active-efflux-and-outer-membrane-diffusion-defines-rules-of-antibiotic-permeation-into-gram-negative-bacteria
#7
Ganesh Krishnamoorthy, Inga V Leus, Jon W Weeks, David Wolloscheck, Valentin V Rybenkov, Helen I Zgurskaya
Gram-negative bacteria are notoriously resistant to antibiotics, but the extent of the resistance varies broadly between species. We report that in significant human pathogens Acinetobacter baumannii, Pseudomonas aeruginosa, and Burkholderia spp., the differences in antibiotic resistance are largely defined by their penetration into the cell. For all tested antibiotics, the intracellular penetration was determined by a synergistic relationship between active efflux and the permeability barrier. We found that the outer membrane (OM) and efflux pumps select compounds on the basis of distinct properties and together universally protect bacteria from structurally diverse antibiotics...
October 31, 2017: MBio
https://www.readbyqxmd.com/read/29079441/in-silico-and-in-vitro-analysis-of-cross-reactivity-between-yersinia-pseudotuberculosis-ompf-porin-and-thyroid-stimulating-hormone-receptor
#8
Olga Portnyagina, Elena Zelepuga, Valentina Khomenko, Elena Solov'eva, Tamara Solov'eva, Olga Novikova
This work is devoted to the ascertainment of serological cross-reactivity between OmpF porin from Yersinia pseudotuberculosis (YpOmpF) and human thyroid-stimulating hormone receptor (hTSHR). Extracts containing hTSHR were isolated from surgical thyroid tissue of patients with clinical and diagnostic signs of diffuse toxic goiter. Monoclonal antibodies to hTSHR (mAbs) were shown to interact both with antigens in thyroid tissue extracts and with YpOmpF. Models of spatial structures of trimer and monomer complexes of YpOmpF with antibodies to hTSHR were also constructed...
October 24, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29063811/emergence-of-colistin-resistance-in-enterobacter-aerogenes-from-croatia
#9
Branka Bedenić, Mirna Vranić-Ladavac, Carolina Venditti, Arjana Tambić-Andrašević, Nada Barišić, Marija Gužvinec, Natalie Karčić, Nicola Petrosillo, Ranko Ladavac, Antonino di Caro
A colistin-resistant Enterobacter aerogenes [study code 12264] was isolated from the tracheal aspirate of a 71-year-old male patient in the General Hospital [GH] in Pula, Croatia. The patient was previously treated in University Hospital Centre in Rijeka with colistin in order to eradicate Acinetobacter baumannii isolate, susceptible only to colistin and tigecycline. Genes encoding ESBLs [blaTEM, blaSHV, blaCTX-M, blaPER-1] were screened by PCR. The strain was shown to possess blaCTX-M-15 and blaTEM-1 genes...
October 24, 2017: Journal of Chemotherapy
https://www.readbyqxmd.com/read/29063141/cmpx-affects-virulence-in-pseudomonas-aeruginosa-through-the-gac-rsm-signaling-pathway-and-by-modulating-c-di-gmp-levels
#10
Anjali Y Bhagirath, Deepti Somayajula, Yanqi Li, Kangmin Duan
Pseudomonas aeruginosa is an ubiquitous organism which is able to infect and colonize many types of hosts including humans. Colonization of P. aeruginosa in chronic infections leads to the formation of biofilms, which are difficult to eradicate. P. aeruginosa is capable of regulating its virulence factors in response to external environment triggers and its signaling mechanism involves two-component regulatory systems and small molecules such as bis-(3'-5')-cyclic dimeric guanosine monophosphate. PA1611-RetS-GacS/A-RsmA/Y/Z is a key regulatory pathway in P...
October 23, 2017: Journal of Membrane Biology
https://www.readbyqxmd.com/read/29038532/the-major-outer-sheath-protein-forms-distinct-conformers-and-multimeric-complexes-in-the-outer-membrane-and-periplasm-of-treponema-denticola
#11
Robbins Puthenveetil, Sanjiv Kumar, Melissa J Caimano, Abhishek Dey, Arvind Anand, Olga Vinogradova, Justin D Radolf
The major outer sheath protein (MOSP) is a prominent constituent of the cell envelope of Treponema denticola (TDE) and one of its principal virulence determinants. Bioinformatics predicts that MOSP consists of N- and C-terminal domains, MOSP(N) and MOSP(C). Biophysical analysis of constructs refolded in vitro demonstrated that MOSP(C), previously shown to possess porin activity, forms amphiphilic trimers, while MOSP(N) forms an extended hydrophilic monomer. In TDE and E. coli expressing MOSP with a PelB signal sequence (PelB-MOSP), MOSP(C) is OM-embedded and surface-exposed, while MOSP(N) resides in the periplasm...
October 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29038444/structural-basis-for-maintenance-of-bacterial-outer-membrane-lipid-asymmetry
#12
Javier Abellón-Ruiz, Shreyas S Kaptan, Arnaud Baslé, Beatrice Claudi, Dirk Bumann, Ulrich Kleinekathöfer, Bert van den Berg
The Gram-negative bacterial outer membrane (OM) is a unique bilayer that forms an efficient permeation barrier to protect the cell from noxious compounds (1)(,)(2) . The defining characteristic of the OM is lipid asymmetry, with phospholipids comprising the inner leaflet and lipopolysaccharides comprising the outer leaflet (1-3) . This asymmetry is maintained by the Mla pathway, a six-component system that is widespread in Gram-negative bacteria and is thought to mediate retrograde transport of misplaced phospholipids from the outer leaflet of the OM to the cytoplasmic membrane (4) ...
October 16, 2017: Nature Microbiology
https://www.readbyqxmd.com/read/29038260/meropenem-vaborbactam-resistance-selection-prevention-and-molecular-mechanisms-in-mutants-of-kpc-producing-klebsiella-pneumoniae
#13
Dongxu Sun, Debora Rubio-Aparicio, Kirk Nelson, Michael N Dudley, Olga Lomovskaya
Vaborbactam (formerly RPX7009) is a new beta-lactamase inhibitor based on a cyclic boronic acid pharmacophore with potent inhibitory activity against Klebsiella pneumoniaecarbapenemases (KPC). It has been developed in combination with meropenem. The objective of these studies was to identify concentrations of both agents associated with selecting or preventing single-step mutations leading to reduced sensitivity to the combination, and to characterize the selected mutations. Eighteen strains of KPC-producing Klebsiella pneumoniae with varying degrees of sensitivity to meropenem (MIC 8-512 μg/ml) and meropenem-vaborbactam (≤0...
October 16, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29038023/the-impact-of-length-variations-in-the-l2-loop-on-the-structure-and-thermal-stability-of-non-specific-porins-the-case-of-ompcs-from-the-yersinia-pseudotuberculosis-complex
#14
T Solov'eva, G Likhatskaya, V Khomenko, K Guzev, N Kim, E Bystritskaya, O Novikova, A Stenkova, A Rakin, M Isaeva
Porins are integral proteins of the outer membranes of gram-negative bacteria. In membranes, they exist as homotrimers and the L2 loops contribute to their stability. Comparison of OmpC porins of the Yersinia pseudotuberculosis complex with other enterobacterial porins demonstrated L2 loop length diversity, which is caused by varying numbers of dipeptide/tripeptide repeats. The OmpC porins are highly homologous to each other, and they can be subdivided into five isoforms based on their L2 loop structure. Optical spectroscopy and SDS-PAGE experiments revealed that particularities of the L2 loops affected the structure and thermal stability of the porins...
October 13, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29034215/the-proteome-of-biologically-active-membrane-vesicles-from-piscirickettsia-salmonis-lf-89-type-strain-identifies-plasmid-encoded-putative-toxins
#15
Cristian Oliver, Mauricio A Hernández, Julia I Tandberg, Karla N Valenzuela, Leidy X Lagos, Ronie E Haro, Patricio Sánchez, Pamela A Ruiz, Constanza Sanhueza-Oyarzún, Marcos A Cortés, María T Villar, Antonio Artigues, Hanne C Winther-Larsen, Ruben Avendaño-Herrera, Alejandro J Yáñez
Piscirickettsia salmonis is the predominant bacterial pathogen affecting the Chilean salmonid industry. This bacterium is the etiological agent of piscirickettsiosis, a significant fish disease. Membrane vesicles (MVs) released by P. salmonis deliver several virulence factors to host cells. To improve on existing knowledge for the pathogenicity-associated functions of P. salmonis MVs, we studied the proteome of purified MVs from the P. salmonis LF-89 type strain using multidimensional protein identification technology...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29033910/resistance-of-animal-strains-of-pseudomonas-aeruginosa-to-carbapenems
#16
Marisa Haenni, Maxime Bour, Pierre Châtre, Jean-Yves Madec, Patrick Plésiat, Katy Jeannot
Carbapenems are major antibiotics reserved to human medicine. This study aimed to investigate the mechanisms of carbapenem resistance of a selection of Pseudomonas aeruginosa veterinary strains from the French network Resapath. Thirty (5.7%) imipenem and/or meropenem non-susceptible P. aeruginosa of canine (n = 24), feline (n = 5), or bovine (n = 1) origin were identified in a large collection of 527 veterinary strains gathered by the Resapath. These resistant isolates belonged to 25 MultiLocus Sequence Types (MLST), of which 17 (68%) are shared with clinical (human) strains, such as high risk clones ST233 and ST395...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29029194/envelope-proteome-changes-driven-by-rama-overproduction-in-klebsiella-pneumoniae-that-enhance-acquired-%C3%AE-lactam-resistance
#17
Juan-Carlos Jiménez-Castellanos, Wan Ahmad Kamil Wan Nur Ismah, Yuiko Takebayashi, Jacqueline Findlay, Thamarai Schneiders, Kate J Heesom, Matthew B Avison
Objectives: In Klebsiella pneumoniae, overproduction of RamA results in reduced envelope permeability and reduced antimicrobial susceptibility but clinically relevant resistance is rarely observed. Here we have tested whether RamA overproduction can enhance acquired β-lactam resistance mechanisms in K. pneumoniae and have defined the envelope protein abundance changes upon RamA overproduction during growth in low and high osmolarity media. Methods: Envelope permeability was estimated using a fluorescent dye accumulation assay...
October 6, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/29028058/protein-protein-interaction-networks-as-a-new-perspective-to-evaluate-distinct-functional-roles-of-voltage-dependent-anion-channel-isoforms
#18
REVIEW
Marianna Caterino, Margherita Ruoppolo, Annalisa Mandola, Michele Costanzo, Stefania Orrù, Esther Imperlini
Voltage-dependent anion channels (VDACs) are a family of three mitochondrial porins and the most abundant integral membrane proteins of the mitochondrial outer membrane (MOM). VDACs are known to be involved in metabolite/ion transport across the MOM and in many cellular processes ranging from mitochondria-mediated apoptosis to the control of energy metabolism, by interacting with cytosolic, mitochondrial and cytoskeletal proteins and other membrane channels. Despite redundancy and compensatory mechanisms among VDAC isoforms, they display not only different channel properties and protein expression levels, but also distinct protein partners...
October 13, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/29026190/growth-hormone-secretagogues-hexarelin-and-jmv2894-protect-skeletal-muscle-from-mitochondrial-damages-in-a-rat-model-of-cisplatin-induced-cachexia
#19
Giuseppe Sirago, Elena Conte, Flavio Fracasso, Antonella Cormio, Jean-Alain Fehrentz, Jean Martinez, Clara Musicco, Giulia Maria Camerino, Adriano Fonzino, Laura Rizzi, Antonio Torsello, Angela Maria Serena Lezza, Antonella Liantonio, Palmiro Cantatore, Vito Pesce
Chemotherapy can cause cachexia, which consists of weight loss associated with muscle atrophy. The exact mechanisms underlying this skeletal muscle toxicity are largely unknown and co-therapies to attenuate chemotherapy-induced side effects are lacking. By using a rat model of cisplatin-induced cachexia, we here characterized the mitochondrial homeostasis in tibialis anterior cachectic muscle and evaluated the potential beneficial effects of the growth hormone secretagogues (GHS) hexarelin and JMV2894 in this setting...
October 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29016383/pathogenesis-of-neisseria-gonorrhoeae-in-the-female-reproductive-tract-neutrophilic-host-response-sustained-infection-and-clinical-sequelae
#20
Jacqueline S Stevens, Alison K Criss
PURPOSE OF REVIEW: Gonorrhea is a major global health concern, caused by the bacterium Neisseria gonorrhoeae. The main clinical feature of acute gonorrhea is neutrophilic influx that is unable to clear infection. Women of reproductive age are predominantly at risk for serious sequelae of gonorrhea, including pelvic inflammatory disease, ectopic pregnancy, and infertility. This review will highlight how neutrophils are recruited to the female reproductive tract (FRT) in response to N. gonorrhoeae, how N...
October 7, 2017: Current Opinion in Hematology
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