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complete genetic analysis of plasmids carrying mcr-1 and other resistance genes in an escherichia coli isolate of animal origin.to investigate the genetic features of three plasmids recovered from an mcr-1 and esbl-producing escherichia coli strain, hyec7, and characterize the transmission mechanism of mcr-1 .201727999050
rapid eucast disc diffusion testing of mdr escherichia coli and klebsiella pneumoniae: inhibition zones for extended-spectrum cephalosporins can be reliably read after 6 h of incubation.the need for rapid antibiotic susceptibility testing increases with escalating levels of antimicrobial resistance in enterobacteriaceae. our objective was to evaluate the accuracy of reading eucast disc diffusion, rosco esbl and carbapenemase detection kits and the mast carbapenemase activity test (cat-id) disc, after 6 h of incubation.201727999046
peptide-conjugated phosphorodiamidate morpholino oligomer (ppmo) restores carbapenem susceptibility to ndm-1-positive pathogens in vitro and in vivo.the objective of this study was to test the efficacy of an inhibitor of the new delhi metallo-β- lactamase (ndm-1). inhibiting expression of this type of antibiotic-resistance gene has the potential to restore antibiotic susceptibility in all bacteria carrying the gene.201727999041
occurrence and characterization of mcr-1-harbouring escherichia coli isolated from pigs in great britain from 2013 to 2015.to determine the occurrence of mcr-1 -harbouring escherichia coli in archived pig material originating in great britain (gb) from 2013 to 2015 and characterize mcr-1 plasmids.201727999032
intrinsic rifamycin resistance of mycobacterium abscessus is mediated by adp-ribosyltransferase mab_0591.rifampicin, a potent first-line tb drug of the rifamycin group, shows only little activity against the emerging pathogen mycobacterium abscessus. reportedly, bacterial resistance to rifampicin is associated with polymorphisms in the target gene rpob or the presence of enzymes that modify and thereby inactivate rifampicin. the aim of this study was to investigate the role of the mab_0591 (arrmab)-encoded rifampicin adp-ribosyltransferase (arr_mab) in innate high-level rifampicin resistance in m. ...201727999011
the synthesis and antifungal activity of (20s)-3β-acetoxy-5α-pregnane-20,16β-carbolactone against fluconazole - resistant candida cells.an efficient procedure for the synthesis of (20s)-3β-acetoxy-5α-pregnane-20,16β-carbolactone is described. bactericidal and fungicidal activity of the lactone against different bacteria such as mssa, mrsa, e. coli esbl, p. aeruginosa and clinical isolates of candida spp., in planktonic and biofilm growth stage were assessed. additionally, the affinity of this new compound to microbial plasma membrane and hemoglobin release from human red blood cells were determined using fluorometric and colorim ...201727998758
improvement of 1,3-propanediol production using an engineered cyanobacterium, synechococcus elongatus by optimization of the gene expression level of a synthetic metabolic pathway and production conditions.the introduction of a synthetic metabolic pathway consisting of multiple genes derived from various organisms enables cyanobacteria to directly produce valuable chemicals from carbon dioxide. we previously constructed a synthetic metabolic pathway composed of genes from escherichia coli, saccharomyces cerevisiae, and klebsiella pneumoniae. this pathway enabled 1,3-propanediol (1,3-pdo) production from cellular dhap via glycerol in the cyanobacterium, synechococcus elongatus pcc 7942. the product ...201727998670
silver complexes of ligands derived from adamantylamines: water-soluble silver-donating compounds with antibacterial properties.two new silver(i) complexes, namely [ag(qyam)2](cf3so3) (1) and [ag(qytam)2](cf3so3) (2), (qyam=2-(quinonyl)iminoadamantane, qytam=2-(quinonyl)iminotriazaadamantane) have been synthesized and characterized by elemental analyses, (1)h nmr, ir, electronic absorption spectroscopy, and x-ray diffraction. the coordination geometry of the silver center in both complexes is distorted tetrahedral where their respective qyam and qytam ligand bind in a bidentate fashion using the imine and quinoline nitro ...201727997857
new silver complexes with bioactive glycine and nicotinamide molecules - characterization, dna binding, antimicrobial and anticancer evaluation.this study introduces a pair of newly synthesized silver complexes, [ag2(hgly)2]n(no3)2n (1) and [ag(nam)2]no3·h2o (2) (gly - glycine, nam - nicotinamide), that were prepared and characterized by relevant methods in solid state (elemental, spectral, thermal and structural analysis) and their stability in solution was verified by (1)h nmr measurements. moreover, suitable reaction conditions were observed by potentiometry depending on ph in case of binary system ag-gly. x-ray analysis confirmed ar ...201727997856
bactericidal mechanism of glutaraldehyde-didecyldimethylammonium bromide as a disinfectant against escherichia coli.this study focuses on the bactericidal mechanism of the new combination of disinfectant glutaraldehyde-didecyldimethylammonium bromide (ga-ddab) against escherichia coli.201727997750
two regulatory rna elements affect tisb-dependent depolarization and persister formation.bacterial survival strategies involve phenotypic diversity which is generated by regulatory factors and noisy expression of effector proteins. the question of how bacteria exploit regulatory rnas to make decisions between phenotypes is central to a general understanding of these universal regulators. we investigated the tisb/istr-1 toxin-antitoxin system of escherichia coli to appreciate the role of the rna antitoxin istr-1 in tisb-dependent depolarization of the inner membrane and persister for ...201727997707
in-silico analysis and implementation of a multicellular feedback control strategy in a synthetic bacterial consortium.living organisms employ endogenous negative feedback loops to maintain homeostasis despite environmental fluctuations. a pressing open challenge in synthetic biology is to design and implement synthetic circuits to control host cells' behavior, in order to regulate and maintain desired conditions. to cope with the high degree of circuit complexity required to accomplish this task and the intrinsic modularity of classical control schemes, we suggest the implementation of synthetic endogenous feed ...201727997140
subinhibitory concentrations of disinfectants promote the horizontal transfer of multidrug resistance genes within and across genera.the greater abundances of antibiotic resistance genes (args) in point-of-use tap and reclaimed water than that in freshly treated water raise the question whether residual disinfectants in distribution systems facilitate the spread of args. this study investigated three widely used disinfectants (free chlorine, chloramine, and hydrogen peroxide) on promoting args transfer within escherichia coli strains and across genera from escherichia coli to salmonella typhimurium. the results demonstrated t ...201727997135
autoinduced and gate controls metabolic pathway dynamically in response to microbial communities and cell physiological state.quorum sensing (qs) systems have been widely applied in biotechnology and synthetic biology that require coordinated, community-level behaviors. meanwhile, the cell physiological state is another key parameter that affects metabolic pathway regulation. here, we designed an autoinduced and gate that responds to both microbial communities and the cell physiological state. a series of tunable qs systems in response to different cell densities were obtained through random mutagenesis of luxr and opt ...201727997131
diastereoselective michael-claisen cyclizations of γ-oxa-α,β-unsaturated ketones en route to 5-oxatetracyclines.5-oxatetracyclines were synthesized from d-arabinose using sequential michael-claisen cyclization reactions via a 5-oxa-ab enone substrate. the 5-oxatetracyclines were found to have poor stability in aqueous buffer (ph 7.4, 37 °c) and showed little to no inhibition of bacterial growth (s. aureus, e. coli).201727996275
methylation-independent adaptation in chemotaxis of escherichia coli involves acetylation-dependent speed adaptation.chemoreceptor methylation and demethylation has been shown to be at the core of the adaptation mechanism in escherichia coli chemotaxis. nevertheless, mutants lacking the methylation machinery can adapt to some extent. here we carried out an extensive quantitative analysis of chemotactic and chemokinetic methylation-independent adaptation. we show that partial or complete adaptation of the direction of flagellar rotation and the swimming speed in the absence of the methylation machinery each occ ...201727995613
intra- and extracellular biosynthesis and characterization of iron nanoparticles from prokaryotic microorganisms with anticoagulant activity.the use of microorganisms for the synthesis of nanoparticles (nps) is relatively new in basic research and technology areas.201727995524
microbial β-galactosidase of pediococcus pentosaceus id-7: isolation, cloning, and molecular characterization.pediococcus pentosaceus id-7 was isolated from kimchi, a korean fermented food, and it showed high activity for lactose hydrolysis. the β-galactosidase of p. pentosaceus id-7 belongs to the gh2 group, which is composed of two distinct proteins. the heterodimeric laclm type of β-galactosidase found in p. pentosaceus id-7 consists of two genes partially overlapped, lacl and lacm encoding lacl (72.2 kda) and lacm (35.4 kda). in this study, escherichia coli mm294 was used for the production of lacl, ...201727994214
an outbreak of diarrhea in mandera, kenya, due to escherichia coli serogroup o-nontypable strain that had a coding gene for enteroaggregative e. coli heat-stable enterotoxin 1.in an outbreak of gastroenteritis in december 2009, in mandera, kenya, escherichia coli o-nontypable (ont) strain was isolated from stool specimens of patients (18/24, 75%). the e. coli ont organisms could not be assigned to any of the recognized diarrheagenic groups of e. coli however, they possessed the enteroaggregative e. coli heat-stable enterotoxin-1 gene. the cell-free culture filtrates of the e. coli ont strain isolated from the outbreak cases induced considerable amount of fluid accumul ...201727994101
novel resolvin d2 receptor axis in infectious inflammation.resolution of acute inflammation is an active process governed by specialized proresolving mediators, including resolvin (rv)d2, that activates a cell surface g protein-coupled receptor, gpr18/drv2. in this study, we investigated rvd2-drv2-dependent resolution mechanisms using drv2-deficient mice (drv2-knockout [ko]). in polymicrobial sepsis initiated by cecal ligation and puncture, rvd2 (∼2.7 nmol/mouse) significantly increased survival (>50%) of wild-type mice and reduced hypothermia and bacte ...201727994074
bcid is a radical s-adenosyl-l-methionine (sam) enzyme that completes bacteriochlorophyllide e biosynthesis by oxidizing a methyl group into a formyl group at c-7.green bacteria are chlorophotorophs that synthesize bacteriochlorophyll (bchl) c, d, or e, which assemble into supramolecular, nanotubular structures in large light-harvesting structures called chlorosomes. the biosynthetic pathways of these chlorophylls are known except for one reaction. null mutants of bcid, which encodes a putative radical s-adenosyl-l-methionine (sam) protein, are unable to synthesize bchl e but accumulate bchl c; however, it is unknown whether bcid is sufficient to convert ...201727994052
human apurinic/apyrimidinic endonuclease (ape1) is acetylated at dna damage sites in chromatin, and acetylation modulates its dna repair activity.apurinic/apyrimidinic (ap) sites, the most frequently formed dna lesions in the genome, inhibit transcription and block replication. the primary enzyme that repairs ap sites in mammalian cells is the ap endonuclease (ape1), which functions through the base excision repair (ber) pathway. although the mechanism by which ape1 repairs ap sites in vitro has been extensively investigated, it is largely unknown how ape1 repairs ap sites in cells. here, we show that ape1 is acetylated (acape1) after bin ...201727994014
development of a novel therapeutic vaccine carrier that sustains high antibody titers against several targets simultaneously.with the aim to improve the efficacy of therapeutic vaccines that target self-antigens, we have developed a novel fusion protein vaccine on the basis of the c-terminal multimerizing end of the variable lymphocyte receptor b (vlrb), the ig equivalent in jawless fishes. recombinant vaccines were produced in escherichia coli by fusing the vlrb sequence to 4 different cancer-associated target molecules. the anti-self-immune response generated in mice that were vaccinated with vlrb vaccines was compa ...201727993994
various sequence types of escherichia coli isolates coharboring blandm-5 and mcr-1 genes from a commercial swine farm in china.sixteen different sequence types (sts) of escherichia coli isolates from a commercial swine farm in china were confirmed to coharbor the carbapenem resistance gene blandm-5 and the colistin resistance gene mcr-1 whole-genome sequencing revealed that blandm-5 and mcr-1 were located on a 46-kb incx3 plasmid and a 32-kb incx4 plasmid, respectively. the two plasmids can transfer together with a low fitness cost, which might explain the presence of various sts of e. coli coharboring blandm-5 and mcr- ...201727993847
comprehensive expression analysis of pathogenicity genes in uropathogenic escherichia coli strains.in this study, we investigated distinct expression patterns of genes encoding iron-acquisition systems, adhesins, protectins, and toxins in human uroepithelial cells infected with 194 uropathogenic escherichia coli (upec) strains in vitro. we assessed the association of these genes with antibiotic resistance genes in this group of upec strains, previously characterised by polymerase chain reaction (pcr). strains were isolated from patients with urinary tract infections (utis) from unidad médica ...201727993701
evaluation of β-d-glucuronidase and particle-size distribution for microbiological water quality monitoring in northern vietnam.in many karst regions in developing countries, the populations often suffer from poor microbial water quality and are frequently exposed to bacterial pathogens. the high variability of water quality requires rapid assays, but the conventional cultivation-based analysis of fecal indicator bacteria, such as escherichia coli (e. coli), is very time-consuming. in this respect, the measurement of the enzymatic activity of e. coli could prove to be a valuable tool for water quality monitoring. a mobil ...201727993473
rational tuning of superoxide sensitivity in soxr, the [2fe-2s] transcription factor: implications of species-specific lysine residues.in escherichia coli, the [2fe-2s] transcriptional factor, soxr, functions as a sensor of oxidative stress. the transcriptional activity in soxr is regulated by the reversible oxidation and reduction of [2fe-2s] clusters. we previously proposed that superoxide (o2(•-)) has a direct role as a signal for e. coli soxr and that the sensitivity of the e. coli soxr response to o2(•-) is 10-fold higher than that of pseudomonas aeruginosa soxr. the difference between the two homologues reflects interspec ...201727992185
fast diazaborine formation of semicarbazide enables facile labeling of bacterial pathogens.bioorthogonal conjugation chemistry has enabled the development of tools for the interrogation of complex biological systems. although a number of bioorthogonal reactions have been documented in literature, they are less ideal for one or several reasons including slow kinetics, low stability of the conjugated product, requirement of toxic catalysts, and side reactions with unintended biomolecules. herein we report a fast (>10(3) m(-1) s(-1)) and bioorthogonal conjugation reaction that joins semi ...201727992180
feasibility study exploring the potential of novel battacin lipopeptides as antimicrobial coatings.colonization of medical implant surfaces by pathogenic microorganisms causes implant failure and undermines their clinical applicability. alarming increase in multidrug-resistant bacteria poses serious concerns with the use of medical implants. antimicrobial peptides (amps) that form part of the innate immune system in all forms of life are attractive alternatives to conventional antibiotics to treat multidrug-resistant bacterial biofilms. the aim of this study was to assess the in vitro antibac ...201727992168
a loop-mediated isothermal amplification method for rapid direct detection and differentiation of nonpathogenic and verocytotoxigenic escherichia coli in beef and bovine faeces.to develop a multiplex loop-mediated isothermal amplification (lamp) assay capable of quantifying escherichia coli and differentiating verocytotoxigenic e. coli (vtec).201727992094
bacteriophage-based bioconjugates as a flow cytometry probe for fast bacteria detection.robust detection of bacteria can significantly reduce risks of nosocomial infections, which are a serious problem even in developed countries (4.1 million cases each year in europe). here we demonstrate utilization of novel multifunctional bioconjugates as specific probes for bacteria detection. bifunctional magnetic-fluorescent microparticles are coupled with bacteriophages. the t4 bacteriophage, due to its natural affinity to bacterial receptors, namely, ompc and lps, enables specific and effi ...201727990800
phenotypic difference between δ(srl-reca)306 and δreca::km elucidated by next-generation sequencing combined with a long-pcr system.many significant gene mutations in e. coli have contributed to the development of genetics. among these, a commonly used reca mutation, δ(srl-reca)306 has been sequenced by a next-generation sequencer combined with a long pcr. an original report described that δ(srl-reca)306 cells were deleted from srlr to reca genes in their genome. the next-generation sequencer enables more accurate details to be determined. we ask whether both surrounding genes from hypf to norv for srlr and alas for reca is ...201727990000
top-down protein identification using isotopic envelope fingerprinting.for top-down protein database search and identification from tandem mass spectra, our isotopic envelope fingerprinting search algorithm and proteingoggle search engine have demonstrated their strength of efficiently resolving heavily overlapping data as well separating non-ideal data with non-ideal isotopic envelopes from ideal ones with ideal isotopic envelopes. here we report our updated proteingoggle 2.0 for intact protein database search with full-capacity. the indispensable updates include ...201727989944
fabrication and characterisation of drug-loaded electrospun polymeric nanofibers for controlled release in hernia repair.the chemical distribution and mechanical effects of drug compounds in loaded electrospun scaffolds, a potential material for hernia repair mesh, were characterised and the efficacy of the material was evaluated. polycaprolactone electrospun fibres were loaded with either the antibacterial agent, irgasan, or the broad-spectrum antibiotic, levofloxacin. the samples were subsequently characterised by rheological studies, scanning electron microscopy (sem), atomic force microscopy (afm), contact ang ...201727988377
electrophoretic mobility, catalytic rate, and activation energy of catalysis of single molecules of the enzyme β-glucuronidase from escherichia coli.single molecule assays were performed on the enzyme e. coli β-glucuronidase using a capillary electrophoresis-based protocol. electrophoretic mobility, catalytic rate and activation energy of catalysis were all found to be heterogeneous. the average mobility at 22°c was -1.1×10(-8)±0.1m(2)v(-1)s(-1) (n=49) with a total range of -0.6 to -1.3×10(-8)m(2)v(-1)s(-1). the range in electrophoretic mobility suggests that the differences in shape or charge of the individual molecules underlying the heter ...201727988292
first survey on antibiotic resistance markers in enterobacteriaceae in cochabamba, bolivia.a molecular survey was conducted in cochabamba, bolivia, to characterize the mechanism involved in the resistance to clinically relevant antibiotics. extended spectrum β-lactamase encoding genes and plasmid-mediated quinolone resistance (pmqr) markers were investigated in a total of 101 oxyimino-cephalosporin-resistant enterobacteria recovered from different health centers during four months (2012-2013). ctx-m enzymes were detected in all isolates, being the ctx-m-1 group the most prevalent (88. ...201727988173
in vivo pharmacodynamics of piperacillin/tazobactam: implications for antimicrobial efficacy and resistance suppression with innovator and generic products.recent studies have shown that the pharmacodynamic (pd) index driving the efficacy of β-lactam/β-lactamase inhibitor combinations such as ceftazidime/avibactam and ceftolozane/tazobactam is the percentage of time the free inhibitor concentration is above a threshold (ft>threshold). however, data with piperacillin/tazobactam (tzp) are scarce. here we aimed to assess the relationship between ft>threshold and tzp antibacterial efficacy by a population pharmacokinetic study in mice and dose-effect e ...201727988068
the effect of preparation processes on the physicochemical characteristics and antibacterial activity of chitooligosaccharides.the bioactivities of chitooligosaccharides are markedly influenced by the degree of acetylation, degree of polymerization or molecular weight and pattern of acetylation. thus, it is crucial to identify reproducible processes that will give rise to well-defined chitooligosaccharides and establish methods for their posterior physicochemical characterization in order to advance in the knowledge of their bioactivity. chitooligosaccharides were prepared by two different processes. the first used chit ...201727987925
construction of silver sulfadiazine loaded chitosan composite sponges as potential wound dressings.chitosan/silver sulfadiazine (cs/agsd) composite sponges were prepared by incorporating agsd particles into cs matrix in order to develop novel biomaterials for wound healing. the co-existence of cs and agsd in the composite sponges was confirmed by sem, ftir and xrd spectra, respectively. the porosity and swelling properties of the fabricated cs/agsd composite sponges were examined and the results indicated that they had high porosity and excellent swelling behaviors. antibacterial property of ...201727987918
original method for synthesis of chitosan-based antimicrobial agent by quaternary ammonium grafting.functionalized high molar mass chitosan derivatives with increased antibacterial properties were prepared by the reaction of chitosan with different quaternary ammonium salts. benzalkonium bromide, pyridinium bromide and triethyl ammonium bromide were synthesized by a quaternization reaction between 1,4-dibromobutane and the respective tertiary amines (n, n-dimethylbenzylamine, triethylamine and pyridine) to obtain three ammonium salts with a bromide end-group capable of reacting with a function ...201727987912
scaffolds of hydroxyl apatite nanoparticles disseminated in 1, 6-diisocyanatohexane-extended poly(1, 4-butylene succinate)/poly(methyl methacrylate) for bone tissue engineering.poly(1, 4-butyl succinate) extended 1, 6-diisocyanatohexane (pbsu-dch) polymers and polymethylmethacrylate (pmma) scaffolds decorated with nano hydroxyl apatite have been prepared and characterized for regeneration of bone in cranio-maxillofacial region. synthesized scaffolds revealed good response in bone regeneration and excellent cell viability in comparison to commercial available glass plate, which lead to better proliferation of mg-63 cell lines. additionally, they demonstrate high porosit ...201727987773
controlled release of cefazolin sodium antibiotic drug from electrospun chitosan-polyethylene oxide nanofibrous mats.antimicrobial electrospun chitosan-polyethylene oxide (cs-peo) nanofibrous mats containing cefazolin, fumed silica (f. silica) and cefazolin-loaded fumed silica nanoparticles (nps) were produced for biomedical applications. the fe-sem images revealed that the f. silica and f. silica-cefazolin nps had average diameters of 40±10 and 60±15nm, respectively. also, the fibers diameters were approximately 160±30, 90±20 and 70±15nm for the pure cs-peo, cs-peo-1% f. silica and cs-peo-1% f. silica-0.5% ce ...201727987755
a novel tantalum-containing bioglass. part ii. development of a bioadhesive for sternal fixation and repair.with over a million median sternotomy surgeries performed worldwide every year, sternal wound complications have posed a serious risk to the affected patients. a rigid therapeutic sternal fixation device has therefore become a necessity. in this work, the incorporation of up to 0.5mol% of tantalum pentoxide (ta2o5), in exchange for zinc oxide (zno), into the sio2-zno-cao-sro-p2o5 glass system is presented. the effect of ta incorporation on the physical, chemical and biological properties of the ...201727987724
antibacterial activity of agricultural waste derived wollastonite doped with copper for bone tissue engineering.bioactive ceramic materials with metal ions generation brought great attention in the class of biomaterials development and widely employed as a filler material for bone tissue regeneration. the present study aimed to fabricate calcium silicate based ceramic material doped with copper metal particles by sol-gel method. rice straw of agricultural waste was utilized as a source material to synthesize wollastonite, then wollastonite was doped with copper to fabricate copper doped wollastonite (cu-w ...201727987672
direct, label-free, selective, and sensitive microbial detection using a bacteriorhodopsin-based photoelectric immunosensor.a photoelectric immunosensor using purple membranes (pm) as the transducer, which contains photoactive bacteriorhodopsin, is here first demonstrated for direct and label-free microbial detection. biotinylated polyclonal antibodies against escherichia coli were immobilized on a pm-coated electrode through further surface biotinylation and bridging avidin or neutravidin. the photocurrent generated by the antibody-coated sensor was reduced after incubation with e. coli k-12 cultures, with the reduc ...201727987407
evaluation of the performance of the iq-check kits and the usda microbiology laboratory guidebook methods for detection of shiga toxin-producing escherichia coli (stec) and stec and salmonella simultaneously in ground beef.to evaluate the performance of the iq-check kits and the usda microbiology laboratory guidebook (mlg) methods for detection of the top seven shiga toxin-producing escherichia coli (stec) (o157:h7, o26, o45, o103, o111, o121 and o145) in ground beef and both stec and salmonella in co-inoculated samples.201727987365
translation system engineering in escherichia coli enhances non-canonical amino acid incorporation into proteins.the ability to site-specifically incorporate non-canonical amino acids (ncaas) into proteins has made possible the study of protein structure and function in fundamentally new ways, as well as the bio synthesis of unnatural polymers. however, the task of site-specifically incorporating multiple ncaas into proteins with high purity and yield continues to present a challenge. at the heart of this challenge lies the lower efficiency of engineered orthogonal translation system components compared to ...201727987323
enhanced succinic acid production under acidic conditions by introduction of glutamate decarboxylase system in e. coli afp111.biological synthesis of succinic acid at low ph values was favored since it not only decreased investment cost but also simplified downstream purification process. in this study, the feasibility of using glutamate decarboxylase system to improve succinic acid production of escherichia coli afp111, a succinate-producing candidate with mutations in pfl, ldha, and ptsg, under acidic conditions was investigated. by overexpressing gadbc operon in afp111, a recombinant named as ba201 (afp111/pmd19t-ga ...201727987090
recombinant expression and characterization of a l-amino acid oxidase from the fungus rhizoctonia solani.l-amino acid oxidases (l-aaos) catalyze the oxidative deamination of l-amino acids to the corresponding α-keto acids, ammonia, and hydrogen peroxide. l-aaos are homodimeric enzymes with fad as a non-covalently bound cofactor. they are of potential interest for biotechnological applications. however, heterologous expression has not succeeded in producing large quantities of active recombinant l-aaos with a broad substrate spectrum so far. here, we report the heterologous expression of an active l ...201727986991
association between inappropriate empirical antimicrobial therapy and hospital length of stay in gram-negative bloodstream infections: stratification by prognosis.the potential benefit from appropriate empirical antimicrobial therapy in patients with favourable prognosis at initial presentation with gram-negative bloodstream infection (bsi) remains unclear. this retrospective cohort study examined the impact of inappropriate empirical antimicrobial therapy on hospital length of stay (hlos) following gram-negative bsi after stratification by predicted prognosis using the bsi mortality risk score (bsimrs).201727986899
overcoming the membrane barrier: recruitment of γ-glutamyl transferase for intracellular release of metabolic cargo from peptide vectors.semipermeable membranes of cells frequently pose an obstacle in metabolic engineering by limiting uptake of substrates, intermediates, or xenobiotics. previous attempts to overcome this barrier relied on the promiscuous nature of peptide transport systems, but often suffered from low versatility or chemical instability. here, we present an alternative strategy to transport cargo molecules across the inner membrane of escherichia coli based on chemical synthesis of a stable cargo-peptide vector c ...201727989807
construction of pduo: a bicistronic shuttle vector series for dual expression of recombinant proteins.our ability to genetically manipulate microbial systems is often hampered by the availability of genetic tools. thus, there is a need for the continued expansion of our molecular tool box. in support of this expansion, this study reports the design, construction, and validation of a new bicistronic shuttle vector series, pduo, for the dual expression of genes in different hosts. each vector was designed and constructed to contain two arac-pbad inducible promoter systems for tight control over ge ...201727989736
serpini2 (pancpin) is an inhibitory serpin targeting pancreatic elastase and chymotrypsin.serpini2/pancpin/mepi is a 46kda member of the serpin (serine protease inhibitor) superfamily. it is downregulated in pancreatic and breast cancer, and associated with acinar cell apoptosis and pancreatic insufficiency when absent in mice. however, the target protease and protein properties of serpini2 are previously uncharacterised. we have expressed and purified recombinant serpin i2 in e. coli. the protein exhibited thermal instability typical of inhibitory serpins, which was lost following r ...201727989643
flexibility in the periplasmic domain of bama is important for function.the β-barrel assembly machine (bam) mediates the biogenesis of outer membrane proteins (omps) in gram-negative bacteria. bama, the central bam subunit composed of a transmembrane β-barrel domain linked to five polypeptide transport-associated (potra) periplasmic domains, is thought to bind nascent omps and undergo conformational cycling to catalyze omp folding and insertion. one model is that conformational flexibility between potra domains is part of this conformational cycling. nuclear magneti ...201727989620
gene architectures that minimize cost of gene expression.gene expression burdens cells by consuming resources and energy. while numerous studies have investigated regulation of expression level, little is known about gene design elements that govern expression costs. here, we ask how cells minimize production costs while maintaining a given protein expression level and whether there are gene architectures that optimize this process. we measured fitness of ∼14,000 e. coli strains, each expressing a reporter gene with a unique 5' architecture. by compar ...201727989436
clinical risk score for prediction of extended-spectrum β-lactamase-producing enterobacteriaceae in bloodstream isolates.objective to develop a risk score to predict probability of bloodstream infections (bsis) due to extended-spectrum β-lactamase-producing enterobacteriaceae (esble). design retrospective case-control study. setting two large community hospitals. patients hospitalized adults with enterobacteriaceae bsi between january 1, 2010, and june 30, 2015. methods multivariate logistic regression was used to identify independent risk factors for esble bsi. point allocation in extended-spectrum β-lactamase pr ...201727989244
mathematical model of lsrr-binding and derepression in escherichia coli k12.quorum sensing (qs) enables bacterial communication and collective behavior in response to self-secreted signaling molecules. unlocking its genetic regulation will provide insight towards understanding its influence on pathogenesis, formation of biofilms, and many other phenotypes. there are few datasets available that link qs-mediated gene expression to its regulatory components and even fewer mathematical models that incorporate known mechanistic detail. by integrating these data with annotate ...201727989220
structural and biochemical characterization of organotin and organolead compounds binding to the organomercurial lyase merb provide new insights into its mechanism of carbon-metal bond cleavage.the organomercurial lyase merb has the unique ability to cleave carbon-hg bonds, and structural studies indicate that three residues in the active site (c96, d99, and c159 in e. coli merb) play important roles in the carbon-hg bond cleavage. however, the role of each residue in carbon-metal bond cleavage has not been well-defined. to do so, we have structurally and biophysically characterized the interaction of merb with a series of organotin and organolead compounds. studies with two known inhi ...201727989130
short carboxylic acid-carboxylate hydrogen bonds can have fully localized protons.short hydrogen bonds (h-bonds) have been proposed to play key functional roles in several proteins. the location of the proton in short h-bonds is of central importance, as proton delocalization is a defining feature of low-barrier hydrogen bonds (lbhbs). experimentally determining proton location in h-bonds is challenging. here, bond length analysis of atomic (1.15-0.98 å) resolution x-ray crystal structures of the human protein dj-1 and its bacterial homologue, yajl, was used to determine the ...201727989121
cag-delta (cag3) protein from the helicobacter pylori 26695 cag type iv secretion system forms ring-like supramolecular assemblies.helicobacter pylori is an important cause of gastric pathologies and persistent infection can lead to stomach cancer. virulent h. pylori strains encode a type iv secretion system responsible for translocation of the oncogenic caga protein into cells of the gastric mucosa. gene hp0522 encodes the essential component cagδ (cag3), and we show by gel filtration and cross-linking that purified cagδ forms high molecular mass complexes. in contrast, its interaction partner cagt is mostly monomeric, but ...201727986823
whole-genome analysis of antimicrobial-resistant and extraintestinal pathogenic escherichia coli in river water.contamination of surface waters by antimicrobial-resistant bacteria and pathogenic bacteria is a great concern. in this study, 531 escherichia coli isolates obtained from the yamato river in japan were evaluated phenotypically for resistance to 25 antimicrobials. seventy-six isolates (14.3%) were multidrug resistant (mdr), 66 (12.4%) were nonsusceptible to one or two classes of agents, and 389 (73.3%) were susceptible. we performed whole-genome sequencing of selected strains by using illumina te ...201727986723
emerging public health challenges of shiga toxin-producing escherichia coli related to changes in the pathogen, the population, and the environment.emerging public health challenges of shiga toxin (stx)-producing escherichia coli (stec) include the occurrence of more frequent or severe disease and risk factors shifts associated with changes, often interconnected, in the pathogen, the population, and the environment. in 3 outbreaks with heightened severity attributed to enhanced pathogen virulence, including the acquisition of an stx2 phage in 1 outbreak, population and environmental factors likely contributed significantly to disease outcom ...201727986670
literature mining supports a next-generation modeling approach to predict cellular byproduct secretion.the metabolic byproducts secreted by growing cells can be easily measured and provide a window into the state of a cell; they have been essential to the development of microbiology, cancer biology, and biotechnology. progress in computational modeling of cells has made it possible to predict metabolic byproduct secretion with bottom-up reconstructions of metabolic networks. however, owing to a lack of data, it has not been possible to validate these predictions across a wide range of strains and ...201727986597
high rates of ctx-m-15-producing escherichia coli and klebsiella pneumoniae in wild boars and barbary macaques in algeria.the present study aimed to screen for the presence of extended-spectrum β-lactamase (esbl)-producing enterobacteriaceae in wild boars and barbary macaques in béjaïa and jijel, algeria.201727984780
[etiological agents more common in primary hip and knee joint replacement infections in older adults].the most common etiological agents in periprosthetic infections are escherichia coli and staphylococcus aureus. the frequency of these infections are found in knee replacement with 0.68 to 1.60% compared to the hip with 0.67 to 2.4%.201727984683
interleukin-1 receptor 2: a new biomarker for sepsis diagnosis and gram-negative/gram-positive bacterial differentiation.this study was undertaken to explore the value of interleukin-1 receptor 2 (il1r2) as a novel potential biomarker for diagnosis of sepsis and discrimination of gram-negative (g)/gram-positive (g) bacterial sepsis. the study was performed in kunming mice and septic patients. inactive escherichia coli or staphylococcus aureus were used to stimulate kunming mice (10 cfu/kg). in clinical study, septic patients with different pathogen infection were studied, and healthy volunteers and patients with s ...201727984536
preparation and properties of cellulose nanocomposite films with in situ generated copper nanoparticles using terminalia catappa leaf extract.in the present work, copper nanoparticles (cunps) were in situ generated inside cellulose matrix using terminalia catappa leaf extract as a reducing agent. during this process, some cunps were also formed outside the matrix. the cunps formed outside the matrix were observed with transmission electron microscope (tem) and scanning electron microscope (sem). majority of the cunps formed outside the matrix were in the size range of 21-30nm. the cellulose/cunp composite films were characterized by f ...201727984140
comparative study on toxicity of extracellularly biosynthesized and laboratory synthesized cdte quantum dots.nanobiosynthesis belongs to the most recent methods for synthesis of nanoparticles. this type of synthesis provides many advantages including the uniformity in particle shape and size. the biosynthesis has also a significant advantage regarding chemical properties of the obtained particles. in this study, we characterized the basic properties and composition of quantum dots (qds), obtained by the extracellular biosynthesis by escherichia coli. furthermore, the toxicity of the biosynthesized qds ...201727984119
age-specific trends in antibiotic resistance in escherichia coli infections in oxford, united kingdom 2013-2014. 201727984045
isolation of detergent-resistant membranes (drms) from escherichia coli.lipid rafts or membrane microdomains have been proposed to compartmentalize cellular processes by spatially organizing diverse molecules/proteins in eukaryotic cells. such membrane microdomains were recently reported to also exist in a few bacterial species. in this work, we report the development of a procedure for membrane microdomain isolation from escherichia coli plasma membranes as well as a method to purify the latter. the method here reported could easily be adapted to other gram-negativ ...201727984012
foodborne enterotoxigenic escherichia coli: from gut pathogenesis to new preventive strategies involving probiotics.enterotoxigenic escherichia coli (etec) are a major cause of traveler's diarrhea and infant mortality in developing countries. given the rise of antibiotic resistance worldwide, there is an urgent need for the development of new preventive strategies. among them, a promising approach is the use of probiotics. although many studies, mostly performed under piglet digestive conditions, have shown the beneficial effects of probiotics on etec by interfering with their survival, virulence or adhesion ...201727983878
evaluation of the efficacy of an autogenous escherichia coli vaccine in broiler breeders.in poultry production escherichia coli autogenous vaccines are often used. however, the efficacy of autogenous e. coli vaccinations has not been evaluated experimentally in chickens after start of lay. the aim of the present study was to evaluate the protective effect of an autogenous e. coli vaccine in broiler breeders. three groups of 28-week-old broiler breeders (unvaccinated, vaccinated once and twice, respectively) were challenged with a homologous e. coli strain (same strain as included in ...201727982712
cross-regulation between two common ancestral response regulators, hprr and cusr, in escherichia coli.the uncharacterized two-component system yedvw of escherichia coli is involved in stress response to hydrogen peroxide. to identify the h2o2-sensing role of yedv, a set of single cys-to-ala substitution mutants were constructed. one particular mutant with c165a substitution in the membrane domain rendered yedv inactive in h2o2-dependent transcription of its regulatory target hiuh. we then proposed to rename yedvw to hprsr (hydrogen peroxide response sensor/regulator). one unique characteristic o ...201727983483
systematic characterization of artificial small rna-mediated inhibition of escherichia coli growth.a new screening system for artificial small rnas (srnas) that inhibit the growth of escherichia coli was constructed. in this system, we used a plasmid library to express rnas of ∼120 nucleotides, each with a random 30-nucleotide sequence that can recognize its target mrna(s). after approximately 60,000 independent colonies were screened, several plasmids that inhibited bacterial growth were isolated. to understand the inhibitory mechanism, we focused on one srna, s-20, that exerted a strong inh ...201727981881
genomewide dam methylation in escherichia coli during long-term stationary phase.dna methylation in prokaryotes is widespread. the most common modification of the genome is the methylation of adenine at the n-6 position. in escherichia coli k-12 and many gammaproteobacteria, this modification is catalyzed by dna adenine methyltransferase (dam) at the gatc consensus sequence and is known to modulate cellular processes including transcriptional regulation of gene expression, initiation of chromosomal replication, and dna mismatch repair. while studies thus far have focused on ...201727981240
biocompatibility and antibacterial activity of nitrogen-doped titanium dioxide nanoparticles for use in dental resin formulations.the addition of antibacterial functionality to dental resins presents an opportunity to extend their useful lifetime by reducing secondary caries caused by bacterial recolonization. in this study, the potential efficacy of nitrogen-doped titanium dioxide nanoparticles for this purpose was determined. nitrogen doping was carried out to extend the ultraviolet absorbance into longer wavelength blue light for increased biocompatibility. titanium dioxide nanoparticles (approximately 20-30 nm) were sy ...201727980404
production and characterization of functional recombinant hybrid heteropolymers of camel hepcidin and human ferritin h and l chains.hepcidin is a liver-synthesized hormone that plays a central role in the regulation of systemic iron homeostasis. to produce a new tool for its functional properties the cdna coding for camel hepcidin-25 was cloned at the 5'end of human fth sequence into the pask-iba43plus vector for expression in escherichia coli the recombinant fusion hepcidin-ferritin-h subunit was isolated as an insoluble iron-containing protein. when alone it did not refold in a 24-mer ferritin molecule, but it did when ren ...201727980120
qsec inhibition as an antivirulence approach for colitis-associated bacteria.hosts and their microbes have established a sophisticated communication system over many millennia. within mammalian hosts, this dynamic cross-talk is essential for maintaining intestinal homeostasis. in a genetically susceptible host, dysbiosis of the gut microbiome and dysregulated immune responses are central to the development of inflammatory bowel disease (ibd). previous surveys of stool from the t-bet(-/-)rag2(-/-) ibd mouse model revealed microbial features that discriminate between healt ...201727980034
worrisome high frequency of extended-spectrum beta-lactamase-producing escherichia coli in community-acquired urinary tract infections: a case-control study.there has been a sustained and dramatic increase in community-acquired urinary tract infections (ca-uti) caused by extended-spectrum beta-lactamase (esbl)-producing bacteria over recent years. despite this, no studies have been performed in low- or middle-income countries. the main objective of this case-control study was to describe esbl ca-uti and its risk factors.201727979787
culture-proven early-onset neonatal sepsis in arab states in the gulf region: two-year prospective study.to investigate the incidence and the pattern of causative organisms of culture-proven early-onset sepsis (eos) in arab states in the gulf region.201727979783
the rava-viaa chaperone-like system interacts with and modulates the activity of the fumarate reductase respiratory complex.regulatory atpase variant a (rava) is a moxr aaa+ protein that functions together with a partner protein that we termed vwa interacting with aaa+ atpase (viaa) containing a von willebrand factor a domain. however, the functional role of rava-viaa in the cell is not yet well established. here, we show that rava-viaa are functionally associated with anaerobic respiration in escherichia coli through interactions with the fumarate reductase (frd) electron transport complex. expression analysis of ra ...201727979649
re: escherichia coli isolates from patients with bacteremic urinary tract infection are genetically distinct from those derived from sepsis following prostate transrectal biopsy. 201727979520
preparation and characterisation of chlorogenic acid-gelatin: a type of biologically active film for coating preservation.chlorogenic acid (cga), a type of plant polyphenol, was conjugated onto gelatin (gel) to prepare a novel coating material for the preservation of fresh seafood. the optimal reaction molar ratio of cga to gelatin (4:1) was determined according to the cga content in the cga-gel conjugate. cga was confirmed to be successfully conjugated onto gelatin by (1)h nuclear magnetic resonance and fourier transform-infrared spectroscopy. the antioxidant activity of cga-gel was proven to be higher than that o ...201727979255
synthesis, antibacterial and antimutagenic activity of zerumbone-bicarbonyl analogues.synthesis of new zerumbone-bicarbonyl analogues by seo2 oxidation is reported. selective oxidation of methyl at c-13 to an aldehyde and a ketone with exo-cyclic double bond between c-13 and c-6 in zerumbone has been recognized. both these compounds have an additional conjugated-carbonyl-functionality. they exhibited significantly higher antimutagenic activity than zerumbone against salmonella tester strains. they are more active against gram positive bacteria than gram negative bacteria; however ...201727979243
nebulized recombinant human tissue factor pathway inhibitor attenuates coagulation and exerts modest anti-inflammatory effects in rat models of lung injury.critically ill patients are at a constant risk of direct (e.g., by pneumonia) or indirect lung injury (e.g., by sepsis). excessive alveolar fibrin deposition is a prominent feature of lung injury, undermining pulmonary integrity and function.201727977318
production of o-glcnac modified recombinant tau in e. coli and detection of ser400 o-glcnac tau in vivo.assembly of the microtubule-associated protein tau (tau) into paired helical filaments that ultimately give rise to neurofibrillary tangles (nfts) makes up one half of the two hallmark pathologies of alzheimer's disease (ad). tau has been shown to be modified with o-linked n-acetylglucosamine residues (o-glcnac), which is the modification of serine and threonine residues of nucleocytoplasmic proteins with n-acetyl-d-glucosamine (glcnac) moieties. increasing o-glcnac in mouse models of tauopathy ...201727975253
a disulfide-bonded dnak dimer is maintained in an atp-bound state.dnak, a major hsp70 molecular chaperones in escherichia coli, is a widely used model for studying hsp70s. we recently solved a crystal structure of dnak in complex with atp and showed that dnak was packed as a dimer in the crystal structure. our previous biochemical studies supported the formation of a specific dnak dimer as observed in the crystal structure in solution in the presence of atp and suggested an important role of this dimer in efficient interaction with hsp40 co-chaperones. in this ...201727975204
expression and secretion of glycosylated heparin biosynthetic enzymes using komagataella pastoris.heparin, an anticoagulant drug, is biosynthesized in selected animal cells. the heparin biosynthetic enzymes mainly consist of sulfotransferases and all are integral transmembrane glycoproteins. these enzymes are generally produced in engineered escherichia coli as without their transmembrane domains as non-glycosylated fusion proteins. in this study, we used the yeast, komagataella pastoris, to prepare four sulfotransferases involved in heparin biosynthesis as glycoproteins. while the yields of ...201727975137
significance of viable but nonculturable escherichia coli: induction, detection, and control.diseases caused by foodborne or waterborne pathogens are emerging. many pathogens can enter into the viable but nonculturable (vbnc) state, which is a survival strategy when exposed to harsh environmental stresses. pathogens in the vbnc state have the ability to evade conventional microbiological detection methods, posing a significant and potential health risk. therefore, controlling vbnc bacteria in food processing and the environment is of great importance. as the typical one of the gram-nega ...201727974738
identification of escherichia coli and shigella species from whole-genome sequences.escherichia coli and shigella species are closely related and genetically constitute the same species. differentiating between these two pathogens and accurately identifying the four species of shigella are therefore challenging. the organism-specific bioinformatics whole-genome sequencing (wgs) typing pipelines at public health england are dependent on the initial identification of the bacterial species by use of a kmer-based approach. of the 1,982 escherichia coli and shigella sp. isolates ana ...201727974538
the promiscuous suma missense suppressor from salmonella enterica has an intriguing mechanism of action.while most missense suppressors have very narrow specificities and only suppress the allele against which they were isolated, the suma missense suppressor from salmonella enterica serovar typhimurium is a promiscuous or broad-acting missense suppressor that suppresses numerous missense mutants. the suma missense suppressor was identified as a glyv trna gly3(gau/c) missense suppressor that can recognize gau or gac aspartic acid codons and insert a glycine amino acid instead of aspartic acid. in a ...201727974497
t4 bacteriophage conjugated magnetic particles for e. coli capturing: influence of bacteriophage loading, temperature and tryptone.this work demonstrates the use of bacteriophage conjugated magnetic particles (fe3o4) for the rapid capturing and isolation of escherichia coli. the investigation of t4 bacteriophage adsorption to silane functionalised fe3o4 with amine (nh2), carboxylic (cooh) and methyl (ch3) surface functional groups reveals the domination of net electrostatic and hydrophobic interactions in governing bacteriophage adsorption. the bare fe3o4 and fe3o4-nh2 with high t4 loading captured 3-fold more e. coli (∼70% ...201727974276
characterisation of extended-spectrum β-lactamase and ampc β-lactamase-producing enterobacteriaceae isolated from companion animals in new zealand.to assess the occurrence of, and characterise, extended-spectrum β-lactamase (esbl) and ampc β-lactamase (ampc)-producing enterobacteriaceae isolated by veterinary diagnostic laboratories from infection sites in companion animals in new zealand.201727973988
integrating ms1 and ms2 scans in high-resolution parallel reaction monitoring assays for targeted metabolite quantification and dynamic (13)c-labeling metabolism analysis.quantification of targeted metabolites, especially trace metabolites and structural isomers, in complex biological materials is an ongoing challenge for metabolomics. initially developed for proteomic analysis, the parallel reaction monitoring (prm) technique exploiting high-resolution ms2 fragment ion data has shown high promise for targeted metabolite quantification. notably, ms1 ion intensity data acquired independently as part of each prm scan cycle are often underutilized in the prm assay. ...201727966897
combining sense and nonsense codon reassignment for site-selective protein modification with unnatural amino acids.incorporation of unnatural amino acids (uaas) via codon reassignment is a powerful approach for introducing novel chemical and biological properties to synthesized polypeptides. however, the site-selective incorporation of multiple uaas into polypeptides is hampered by the limited number of reassignable nonsense codons. this challenge is addressed in the current work by developing escherichia coli in vitro translation system depleted of specific endogenous trnas. the translational activity in th ...201727966891
meso-acetoxymethyl bodipy dyes for photodynamic therapy: improved photostability of singlet oxygen photosensitizers.we report two bodipy based photosensitizers (br2boac and i2boac) featuring an acetoxymethyl substituent at the meso-position. these photosensitizers show improved photostability against singlet oxygen, when compared to a bodipy photosensitizer lacking the acetoxymethyl group. both compounds were evaluated for photodynamic therapy against hela cells and photodynamic inactivation against e. coli bacteria. we show that the compounds readily embed in the lipid membranes of hela cervical cancer cells ...201727966708
promoting resuscitation of viable but nonculturable cells of vibrio harveyi by a resuscitation-promoting factor-like protein yeaz.to demonstrate the resuscitation-promoting activities of recombinant yeaz from vibrio harveyi sf-1.201727966258
new aminoglycoside-modifying enzymes aph(3')-viii and aph(3')-ix in acinetobacter rudis and acinetobacter gerneri.analysis of whole-genome sequences of 133 strains of acinetobacter detected two genes for new types of aminoglycoside 3'-o-phosphotransferase [aph(3')], type viii in acinetobacter rudis and ix in a. gerneri. the enzymes were related to each other (49% identity) and to aph(3')-vi (61% and 51% identity, respectively), which is intrinsic to a. guillouiae. the cloned genes conferred kanamycin and amikacin resistance to escherichia coli but were cryptic or expressed at low levels in the original host ...201727965516
reversible aggregation of hiv-1 gag proteins mediated by nucleic acids.hiv-1 gag protein is the major structural protein for the assembly of virion particles. although studies have been carried out using partially purified gag proteins to investigate the mechanisms of viral particle assembly, the outcomes of an assembly reaction remain controversial. here we have developed an improved procedure for purification of several untagged retroviral gag proteins from e. coli to more than 95% purity and characterized gag assembly in solution. we found that hiv-1 gag protein ...201727965093
a novel cmos image sensor system for quantitative loop-mediated isothermal amplification assays to detect food-borne pathogens.loop-mediated isothermal amplification (lamp) is considered as one of the alternatives to the conventional pcr and it is an inexpensive portable diagnostic system with minimal power consumption. the present work describes the application of lamp in real-time photon detection and quantitative analysis of nucleic acids integrated with a disposable complementary-metal-oxide semiconductor (cmos) image sensor. this novel system works as an amplification-coupled detection platform, relying on a cmos i ...201727965010
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