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https://www.readbyqxmd.com/read/28433723/elimination-of-the-cryptic-plasmid-in-leuconostoc-citreum-by-crispr-cas9-system
#1
Ye-Ji Jang, Seung-Oh Seo, Seul-Ah Kim, Ling Li, Tae-Jip Kim, Sun Chang Kim, Yong-Su Jin, Nam Soo Han
Leuconostoc spp. are important lactic acid bacteria for the fermentation of foods. In particular, L. citreum strains isolated from various foods have been used as host strains for genetic and metabolic engineering studies. In order to develop a food-grade genetic engineering system, L. citreum CB2567 was isolated from Kimchi. However, the isolated bacterium contained a cryptic plasmid which was difficult to eliminate. As the existence of the plasmid might hinder strain engineering, we eliminated the plasmid using an RNA-guided DNA endonuclease CRISPR/Cas9 system...
April 19, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28432959/molecular-dynamics-simulation-studies-of-novel-%C3%AE-lactamase-inhibitor
#2
Farhan Ul Haq, Asma Abro, Saad Raza, Klaus R Liedl, Syed Sikander Azam
New Delhi Metallo-β-Lactamase-1 (NDM-1) has drawn great attention due to its diverse antibiotic resistant activity. It can hydrolyze almost all clinically available β-lactam antibiotics. To inhibit the activity of NDM-1 a new strategy is proposed using computational methods. Molecular dynamics (MD) simulations are used to analyze the molecular interactions between selected inhibitor candidates and NDM-1 structure. The enzyme-ligand complex is subject to binding free energy calculations using MM(PB/GB)SA methods...
April 4, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28426232/glycine-substitution-reduces-antimicrobial-activity-and-helical-stretch-of-dipgla-h-in-lipid-micelles
#3
Marc-Antoine Sani, Catharina Saenger, Davor Juretic, Frances Separovic
With the rise in antibiotic resistance, antimicrobial peptides (AMPs) show promise for therapeutic development but higher specificity is required. PGLa-H is a naturally occurring decapeptide, reported to have moderate antibacterial activity and low hemolytic activity, with its sequence being identical to the C-terminal fragment of highly selective AMP, PGLa. DiPGLa-H, a sequential tandem repeat of PGLa-H, as well as Kiadin, an analogue with a Val to Gly substitution at position 15, display improved in vitro bactericidal activity against both Gram-negative and Gram-positive pathogens, with generally low toxicity for human cells...
April 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28416559/a-novel-non-antibiotic-nitroglycerin-based-catheter-lock-solution-for-the-prevention-of-intraluminal-central-venous-catheter-infections-in-cancer-patients
#4
Anne-Marie Chaftari, Ray Hachem, Ariel Szvalb, Mahnaz Taremi, Bruno Granwehr, George Michael Viola, Amin Sapna, Andrew Assaf, Numan Yazan, Pankil Shah, Ketevan Gasitashvili, Elizabeth Natividad, Ying Jiang, Rebecca Slack, Ruth Reitzel, Joel Rosenblatt, Elie Mouhayar, Issam Raad
Background: For long-term central lines (CL), the lumen is the major source of central line associated bloodstream infections (CLABSI). Current standard of care for maintaining catheter patency includes flushing the CL with saline or heparin. Neither agent has any antimicrobial activity. Furthermore heparin may enhance staphylococcal biofilm formation. We evaluated the safety and efficacy of a novel non-antibiotic catheter lock solution for the prevention of CLABSI.Patients and Methods: Between November 2015, and February 2016, we enrolled 60 patients with hematologic malignancies who had peripherally inserted central catheter (PICC) to receive the study lock solution...
April 17, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28416110/structural-basis-for-kinase-mediated-macrolide-antibiotic-resistance
#5
Desiree H Fong, David L Burk, Jonathan Blanchet, Amy Y Yan, Albert M Berghuis
The macrolides are a class of antibiotic, characterized by a large macrocyclic lactone ring that can be inactivated by macrolide phosphotransferase enzymes. We present structures for MPH(2')-I and MPH(2')-II in the apo state, and in complex with GTP analogs and six different macrolides. These represent the first structures from the two main classes of macrolide phosphotransferases. The structures show that the enzymes are related to the aminoglycoside phosphotransferases, but are distinguished from them by the presence of a large interdomain linker that contributes to an expanded antibiotic binding pocket...
April 1, 2017: Structure
https://www.readbyqxmd.com/read/28415016/an-lc-ms-ms-method-for-the-determination-of-antibiotic-residues-in-distillers-grains
#6
Kaleb J Duelge, Upul Nishshanka, Hemakanthi G De Alwis
Antibiotics are used in ethanol production to discourage the growth of bacteria that would result in lower ethanol content and a lower quality product. A survey conducted by the FDA (FY 2010 Nationwide Survey of Distillers Grains for Antibiotic Residues, 2009 [1]) revealed that the residues of these antibiotics can remain in the distillers grains (DG) by-product, which is used as an animal feed ingredient. The low levels of antibiotic residues in DG could be a public health concern, as they could lead to antimicrobial resistance...
April 1, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28406359/enantioselective-analysis-of-chloramphenicol-residues-in-honey-samples-by-chiral-lc-msms-and-results-of-a-honey-survey
#7
Gerhard G Rimkus, Dirk Hoffmann
Chloramphenicol (CAP) is a broad-spectrum antibiotic used widely both in human and in veterinary medication. Since 1994 CAP is not authorised anymore for use in food-producing animals in the EU due to several adverse effects. A minimum required performance level (MRPL) 0.3 µg kg(-1) was established in 2003. CAP molecule contains two asymmetric centres thus in total four para-CAP stereoisomers exist. Only the RR-CAP enantiomer is bioactive having significant antimicrobial activity. For the first time a chiral LC/MSMS method is reported to identify and quantify the four CAP enantiomers at residue levels in honey samples...
April 13, 2017: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
https://www.readbyqxmd.com/read/28406299/discovery-and-optimization-of-isoquinoline-ethyl-ureas-as-antibacterial-agents
#8
Philippe Panchaud, Thierry Bruyère, Anne-Catherine Blumstein, Daniel Bur, Alain Chambovey, Eric A Ertel, Markus Gude, Christian Hubschwerlen, Loïc Jacob, Thierry Kimmerlin, Thomas Pfeifer, Lars Prade, Peter Seiler, Daniel Ritz, Georg Rueedi
Our strategy to combat resistant bacteria consisted in targeting the GyrB/ParE ATP-binding sites located on bacterial DNA gyrase and topoisomerase IV and not utilized by marketed antibiotics. Screening around the minimal ethyl urea binding motif led to the identification of isoquinoline ethyl urea 13 as promising starting point for fragment evolution. The optimization was guided by structure-based design and focused on antibacterial activity in vitro and in vivo, culminating in the discovery of unprecedented substituents able to interact with conserved residues within the ATP-binding site...
April 13, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28402029/magnetic-solid-phase-extraction-based-on-carbon-nanotubes-for-the-determination-of-polyether-antibiotics-and-s-triazine-drug-residues-in-animal-food-with-lc-ms
#9
Xiaoxing Liu, Shuyu Xie, Tengteng Ni, Dongmei Chen, Xu Wang, Yuanhu Pan, Yulian Wang, Lingli Huang, Guyue Cheng, Wei Qu, Zhenli Liu, Yanfei Tao, Zonghui Yuan
Carbon nanotubes-magnetic nanoparticles, comprising ferroferric oxide nanoparticles and carbon nanotubes, were prepared through a simple one-step synthesis method and subsequently applied to magnetic solid-phase extraction for the determination of polyether antibiotic and s-triazine drug residues in animal food coupled with liquid chromatography with tandem mass spectrometry. The nanocomposites were characterized by transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The components within the nanocomposites endowed the material with high extraction performance and manipulative convenience...
April 12, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28396353/the-histidine-residue-of-qsec-is-required-for-canonical-signaling-between-qseb-and-pmrb-in-uropathogenic-escherichia-coli
#10
Erin J Breland, Ellisa W Zhang, Tomas Bermudez, Charles R Martinez, Maria Hadjifrangiskou
Two-component systems are prototypically comprised of a histidine kinase (sensor) and a response regulator (responder). The sensor kinases auto-phosphorylate at a conserved histidine residue, acting as a phospho-donor for subsequent phosphotransfer to and activation of a cognate response regulator. In rare cases, the histidine residue is also essential for response regulator de-phosphorylation via a reverse-phosphotransfer reaction. In this work, we present an example of a kinase that relies on reverse-phosphotransfer to catalyze the de-phosphorylation of its cognate partner...
April 10, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28396351/ms2-lysis-of-escherichia-coli-depends-on-host-chaperone-dnaj
#11
Karthik R Chamakura, Jennifer S Tran, Ry Young
The L protein of the ssRNA phage MS2 causes lysis of E. coli without inducing a bacteriolytic activity or inhibiting net peptidoglycan (PG) synthesis. To find host genes required for L-mediated lysis, spontaneous Ill ( insensitivity to Llysis) mutants were selected as survivors of L expression and shown to have a missense change of the highly-conserved proline (P330Q) in the C-terminal domain of DnaJ. In the dnaJP330Q host, L-mediated lysis is completely blocked at 30°C without affecting the intracellular levels of L...
April 10, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28395259/effects-of-18-pharmaceuticals-on-the-physiological-diversity-of-edaphic-microorganisms
#12
Mª Rosa Pino-Otín, Selene Muñiz, Jonatan Val, Enrique Navarro
Pharmaceutical residues can enter the terrestrial environment through the application of recycled water and contaminated biosolids to agricultural soils, were edaphic microfauna can would be threatened. This study thus assessed the effect of 18 widely consumed pharmaceuticals, belonging to four groups: antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), blood lipid-lowering agents (BLLA) and β-blockers, on the physiology of soil microbial communities from a ecological crop field. Biolog EcoPlates, containing 31 of the most common carbon sources found in forest and crop soils, were used to calculate both the averaged well colour development (AWCD), as an indicator of the entire capacity of degrading carbon sources, and the diversity of carbon source utilization, as an indicator of the physiological diversity...
April 7, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28394116/improvement-of-soil-ecosystem-multifunctionality-by-dissipating-manure-induced-antibiotics-and-resistance-genes
#13
Yuting Liang, Meng Pei, Dandan Wang, Shengnan Cao, Xian Xiao, Bo Sun
The application of animal manure containing antibiotic residues to farmlands as an organic fertilizer causes a long-term potential threat to the ecological environment of farmland. This study analyzed the effects of abating typical antibiotics and resistance genes (ARGs) applied with pig manure on farmland soil as well as on soil ecosystem multifunctionality (EMF) and its influencing factor. The results showed that Lolium multiflorum exhibited significantly stronger abatement of typical antibiotics and ARGs when combined with biochar than when used alone (p < 0...
April 13, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28391456/characterization-of-extracellular-polymeric-substances-in-biofilms-under-long-term-exposure-to-ciprofloxacin-antibiotic-using-fluorescence-excitation-emission-matrix-and-parallel-factor-analysis
#14
Chaochao Gu, Pin Gao, Fan Yang, Dongxuan An, Mariya Munir, Hanzhong Jia, Gang Xue, Chunyan Ma
The presence of antibiotic residues in the environment has been regarded as an emerging concern due to their potential adverse environmental consequences such as antibiotic resistance. However, the interaction between antibiotics and extracellular polymeric substances (EPSs) of biofilms in wastewater treatment systems is not entirely clear. In this study, the effect of ciprofloxacin (CIP) antibiotic on biofilm EPS matrix was investigated and characterized using fluorescence excitation-emission matrix (EEM) and parallel factor (PARAFAC) analysis...
April 8, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28390021/pharmaceuticals-and-illicit-drugs-in-wastewater-samples-in-north-eastern-tunisia
#15
Bilel Moslah, Evroula Hapeshi, Amel Jrad, Despo Fatta-Kassinos, Abderrazek Hedhili
Pharmaceutically active substances (PhACs) and drugs of abuse (DAs) are two classes of contaminants of emerging concern that have attracted great concern and interest by the scientific community during the last two decades. Numerous studies have revealed their presence in treated urban wastewaters. This is mainly due to the fact that some compounds are not efficiently removed during wastewater treatment processes, and are thus able to reach the aquatic environment through wastewater discharge and reuse practices...
April 7, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28378223/biodegradation-of-sulfamethazine-by-an-isolated-thermophile-geobacillus-sp-s-07
#16
Lan-Jia Pan, Xiao-da Tang, Chun-Xing Li, Guang-Wei Yu, Yin Wang
Sulfamethazine (SM2) is an antimicrobial drug that is frequently detected in manure compost, is difficult to degrade at high temperatures and is potentially threatening to the environment. In this study, a thermophilic bacterium was isolated from the activated sludge of an antibiotics pharmaceutical factory; this bacterium has the ability to degrade SM2 at 70 °C, which is higher than the traditional manure composting temperature. The strain S-07 is closely related to Geobacillus thermoleovorans based on its 16S rRNA gene sequence...
May 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28370529/conformational-flexibility-of-the-glycosidase-nagz-allows-it-to-bind-structurally-diverse-inhibitors-to-suppress-%C3%AE-lactam-antibiotic-resistance
#17
Grishma Vadlamani, Keith A Stubbs, Jérôme Désiré, Yves Blériot, David J Vocadlo, Brian L Mark
NagZ is a N-acetyl-β-D-glucosaminidase that participates in the peptidoglycan (PG) recycling pathway of Gram-negative bacteria by removing N-acetyl-glucosamine (GlcNAc) from PG fragments that have been excised from the cell wall during growth. The 1,6-anhydromuramoyl-peptide products generated by NagZ activate β-lactam resistance in many Gram-negative bacteria by inducing the expression of AmpC β-lactamase. Blocking NagZ activity can thereby suppress β-lactam antibiotic resistance in these bacteria. The NagZ active site is dynamic and it accommodates distortion of the glycan substrate during catalysis using a mobile catalytic loop that carries a histidine residue which serves as the active site general acid/base catalyst...
March 28, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28369621/critical-23s-rrna-interactions-for-macrolide-dependent-ribosome-stalling-on-the-ermcl-nascent-peptide-chain
#18
Miriam Koch, Jessica Willi, Ugo Pradère, Jonathan Hall, Norbert Polacek
The nascent peptide exit tunnel has recently been identified as a functional region of ribosomes contributing to translation regulation and co-translational protein folding. Inducible expression of the erm resistance genes depends on ribosome stalling at specific codons of an upstream open reading frame in the presence of an exit tunnel-bound macrolide antibiotic. The molecular basis for this translation arrest is still not fully understood. Here, we used a nucleotide analog interference approach to unravel important functional groups on 23S rRNA residues in the ribosomal exit tunnel for ribosome stalling on the ErmC leader peptide...
March 21, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28366652/transparent-ciprofloxacin-povidone-antibiotic-films-and-nanofiber-mats-as-potential-skin-and-wound-care-dressings
#19
Marco Contardi, José A Heredia-Guerrero, Giovanni Perotto, Paola Valentini, Pier Paolo Pompa, Raffaele Spanò, Luca Goldoni, Rosalia Bertorelli, Athanassia Athanassiou, Ilker S Bayer
Water insoluble monohydrochloride monohydrate free ciprofloxacin (Cipro) antibiotic was incorporated in polyvinylpyrrolidone (PVP) polymer matrix by using acetic acid co-solvent in water. The resultant solutions were cast into fully transparent antimicrobial films. Proper concentrations of acetic acid eliminated in situ crystallization of the antibiotic and the resultant phase separation upon solvent evaporation. The solutions could also be electrospun into nanofiber mats (non-transparent). Presence of residual PVP-bound acetic acid in dry PVP films induced unprecedented levels of plasticity (stretching capacity) and softness to the films...
March 31, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28365994/efficient-reduction-of-antibacterial-activity-and-cytotoxicity-of-fluoroquinolones-by-fungal-mediated-n-oxidation
#20
Marina Rusch, Astrid Spielmeyer, Jessica Meißner, Manfred Kietzmann, Holger Zorn, Gerd Hamscher
Extensive usage of fluoroquinolone antibiotics in livestock results in their occurrence in manure and subsequently in the environment. Fluoroquinolone residues may promote bacterial resistance and are toxic to plants and aquatic organisms. Moreover, fluoroquinolones may enter the food chain through plant uptake, if manure is applied as fertilizer. Thus, the presence of fluoroquinolones in the environment may pose a threat to human and ecological health. In this study, the biotransformation of enrofloxacin, marbofloxacin, and difloxacin by the fungus X...
April 10, 2017: Journal of Agricultural and Food Chemistry
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