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https://www.readbyqxmd.com/read/28102518/quercetin-glucoside-production-by-engineered-escherichia-coli
#1
REVIEW
Tian Xia, Mark A Eiteman
Escherichia coli strains expressing the O-glucosyltransferases UGT73B3 or UGT84B1 were compared for the production of glucosides from quercetin supplied into a defined medium. The formation of quercetin-3-glucoside (Q3G) by UGT73B3 showed a maximum at 33 °C, while the formation of quercetin-7-glucoside by UGT84B1 increased with increasing temperature to 37 °C. The highest concentrations of Q3G were attained by strains having a deletion in the pgi gene-coding phosphoglucose isomerase, which effectively blocked the entry of glucose-6P into the Embden-Meyerhof-Parnas pathway...
January 19, 2017: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/28102224/optimality-and-sub-optimality-in-a-bacterial-growth-law
#2
Benjamin D Towbin, Yael Korem, Anat Bren, Shany Doron, Rotem Sorek, Uri Alon
Organisms adjust their gene expression to improve fitness in diverse environments. But finding the optimal expression in each environment presents a challenge. We ask how good cells are at finding such optima by studying the control of carbon catabolism genes in Escherichia coli. Bacteria show a growth law: growth rate on different carbon sources declines linearly with the steady-state expression of carbon catabolic genes. We experimentally modulate gene expression to ask if this growth law always maximizes growth rate, as has been suggested by theory...
January 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28101963/extreme-biophysics-enzymes-under-pressure
#3
Qi Huang, Jocelyn M Rodgers, Russell J Hemley, Toshiko Ichiye
A critical question about piezophilic (pressure-loving) microbes is how their constituent molecules maintain function under high pressure. Here, factors are examined that may lead to the increased activity under pressure in dihydrofolate reductase from the piezophilic Moritella profunda compared to the homologous enzyme from the mesophilic Escherichia coli. Molecular dynamics simulations are performed at various temperatures and pressures to examine how pressure affects the flexibility of the enzymes from these two microbes, since both stability and flexibility are necessary for enzyme activity...
January 19, 2017: Journal of Computational Chemistry
https://www.readbyqxmd.com/read/28100778/structure-of-the-z-ring-associated-protein-zapd-bound-to-the-c-terminal-domain-of-the-tubulin-like-protein-ftsz-suggests-mechanism-of-z-ring-stabilization-through-ftsz-crosslinking
#4
Maria Schumacher, Kuo-Hsiang Huang, Wenjie Zeng, Anuradha Janakiraman
Cell division in most bacteria is mediated by the tubulin-like FtsZ protein, which polymerizes in a GTP-dependent manner to form the cytokinetic Z ring. A diverse repertoire of FtsZ binding proteins affect FtsZ localization and polymerization to ensure correct Z ring formation. Many of these proteins bind the C-terminal domain (CTD) of FtsZ, which serves as a hub for FtsZ regulation. FtsZ ring-associated proteins, ZapA-D (Zaps), are important FtsZ regulatory proteins that stabilize FtsZ assembly and enhance Z ring formation by increasing lateral assembly of FtsZ protofilaments, which then form the Z ring...
January 18, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28100677/paired-siglec-receptors-generate-opposite-inflammatory-responses-to-a-human-specific-pathogen
#5
Flavio Schwarz, Corinna S Landig, Shoib Siddiqui, Ismael Secundino, Joshua Olson, Nissi Varki, Victor Nizet, Ajit Varki
Paired immune receptors display near-identical extracellular ligand-binding regions but have intracellular sequences with opposing signaling functions. While inhibitory receptors dampen cellular activation by recognizing self-associated molecules, the functions of activating counterparts are less clear. Here, we studied the inhibitory receptor Siglec-11 that shows uniquely human expression in brain microglia and engages endogenous polysialic acid to suppress inflammation. We demonstrated that the human-specific pathogen Escherichia coli K1 uses its polysialic acid capsule as a molecular mimic to engage Siglec-11 and escape killing...
January 18, 2017: EMBO Journal
https://www.readbyqxmd.com/read/28100599/rapid-and-specific-detection-of-the-escherichia-coli-sequence-type-648-complex-stc648-within-phylogroup-f
#6
James R Johnson, Brian D Johnston, David M Gordon
The Escherichia coli sequence type 648 complex (STc648) is an emerging lineage within phylogroup F - formerly included within phylogroup D - that is associated with multidrug resistance. Here, we designed and validated a novel multiplex PCR-based assay for STc648 that took advantage of (i) four distinctive single-nucleotide polymorphisms in icd allele 96 and gyrB allele 87, two of the multi-locus sequence typing alleles that define ST648, and (ii) the typical absence within STc648 of uidA, an E. coli-specific gene encoding β-glucuronidase...
January 18, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28100305/environment-directed-activation-the-escherichia-coli-flhdc-operon-by-transposons
#7
Zhongge Zhang, Chika Kukita, Mir Zafri Humayun, Milton H Saier
The flagellar system in E. coli K12 is expressed under the control of the flhDC-encoded master regulator, FlhDC. Transposition of insertion sequence (IS) elements to the upstream flhDC promoter region up-regulates transcription of this operon, resulting in more rapid motility. Wang and Wood (2011) provided evidence that insertion of IS5 into upstream activating sites occurs at higher rates in semisolid agar media in which swarming behavior is allowed as compared with liquid or solid media where swarming cannot occur...
January 17, 2017: Microbiology
https://www.readbyqxmd.com/read/28100054/efficacy-of-silver-hydrophilic-poly-p-xylylene-on-preventing-bacterial-growth-and-biofilm-formation-in-urinary-catheters
#8
Hamideh Heidari Zare, Viktorija Juhart, Attila Vass, Gerhard Franz, Dieter Jocham
Catheter associated urinary tract infections (CAUTI), caused by several strains of bacteria, are a common complication for catheterized patients. This may eventually lead to a blockage of the catheter due to the formation of a crystalline or amorphous biofilm. Inhibiting bacteria should result in a longer application time free of complaints. This issue has been investigated using an innovative type of silver-coated catheter with a semipermeable cap layer to prevent CAUTI. In this work, two different types of silver catheters were investigated, both of which were capped with poly(p-xylylene) (PPX-N) and exhibited different surface properties that completely changed their wetting conduct with water...
January 18, 2017: Biointerphases
https://www.readbyqxmd.com/read/28099463/the-differential-effects-of-anesthetics-on-bacterial-behaviors
#9
Matthew Chamberlain, Sophia Koutsogiannaki, Matthew Schaefers, Hasan Babazada, Renyu Liu, Koichi Yuki
Volatile anesthetics have been in clinical use for a long period of time and are considered to be promiscuous by presumably interacting with several ion channels in the central nervous system to produce anesthesia. Because ion channels and their existing evolutionary analogues, ion transporters, are very important in various organisms, it is possible that volatile anesthetics may affect some bacteria. In this study, we hypothesized that volatile anesthetics could affect bacterial behaviors. We evaluated the impact of anesthetics on bacterial growth, motility (swimming and gliding) and biofilm formation of four common bacterial pathogens in vitro...
2017: PloS One
https://www.readbyqxmd.com/read/28099388/valproic-acid-mitigates-the-inflammatory-response-and-prevents-acute-respiratory-distress-syndrome-in-a-murine-model-of-escherichia-coli-pneumonia-at-the-expense-of-bacterial-clearance
#10
George Kasotakis, Manuel Galvan, Elizabeth King, Beda Sarkar, Arthur Stucchi, Joseph P Mizgerd, Peter A Burke, Daniel Remick
BACKGROUND: Histone deacetylase inhibitors (HDACI) are members of a family of epigenetic modifying agents with broad anti-inflammatory properties. These anti-inflammatory properties may have important therapeutic implications in Acute Respiratory Distress Syndrome (ARDS). However, administration of HDACI may create an immunosuppressive environment conducive to bacterial growth. Accordingly, the aim of the current study is to investigate the effect of HDACI Valproic Acid (VPA) on host inflammatory response and bacterial burden in a murine model of E...
January 18, 2017: Journal of Trauma and Acute Care Surgery
https://www.readbyqxmd.com/read/28099089/genotypic-characterization-of-quinolone-resistant-escherichia-coli-isolates-from-retail-food-in-morocco
#11
Kaotar Nayme, Abouddihaj Barguigua, Brahim Bouchrif, Bouchra Karraouan, Fatima El Otmani, Naima Elmdaghri, Khalid Zerouali, Mohammed Timinouni
This study was conducted to assess the retail food as a possible vehicle for antimicrobial resistant, particularly quinolones resistant and pathogenic Escherichia coli. We determined the prevalence and characteristics of nalidixic acid (Nal) resistant E. coli isolates from diverse retail food samples. In all, 70 (28%) of 250 E. coli isolates studied were Nal-resistant E. coli and 91% of these were multi-drug resistant. Plasmid mediated quinolone resistance genes were identified in 32 isolates, including aac(6')-Ib-cr (n = 16), qnrS1 (n = 11) and qnrB19 (n = 7)...
February 2017: Journal of Environmental Science and Health. Part. B, Pesticides, Food Contaminants, and Agricultural Wastes
https://www.readbyqxmd.com/read/28099062/rectal-carriage-of-extended-spectrum-beta-lactamase-and-carbapenemase-producing-gram-negative-bacilli-in-intensive-care-units-in-tunisia
#12
Samia Hammami, Chaima Dahdeh, Kelthoum Mamlouk, Sana Ferjeni, Elaa Maamar, Zeineb Hamzaoui, Mabrouka Saidani, Salma Ghedira, Mohamed Houissa, Amin Slim, Ilhem Boutiba-Ben Boubaker
This study was conducted to evaluate the rate of fecal carriage of Gram-negative bacilli (GNB) resistant to third-generation cephalosporins (third GC) in patients hospitalized in the intensive care unit (ICU) of Charles Nicolle Hospital of Tunis and to identify the enzymatic mechanisms involved. From February to April 2014, rectal swabs were collected from all patients (n = 38) at admission and once weekly thereafter to identify acquisition. They were cultured on desoxycholate-lactose-agar plates supplemented with cefotaxime (2 mg/L)...
January 18, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28099061/iodometric-and-molecular-detection-of-esbl-production-among-clinical-isolates-of-e-coli-fingerprinted-by-eric-pcr-the-first-egyptian-report-declares-the-emergence-of-e-coli-o25b-st131clone-harboring-blages
#13
Mohamed F El-Badawy, Wael M Tawakol, Ibrahim A Maghrabi, Moselhy S Mansy, Mohamed M Shohayeb, Mohammed S Ashour
The extensive use of β-lactam antibiotics has led to emergence and spread of extended-spectrum β-lactamases (ESBLs). This study was conducted to investigate the prevalence of 7 different ESBL genes (blaTEM, blaSHV, blaCTX-M, blaVEB, blaPER, blaGES, and blaOXA-10) and O25b-ST131 high-risk clone among 61 clinical isolates of Escherichia coli. Also, one broad-spectrum β-lactamase (blaOXA-1) was investigated. This study was also constructed to evaluate iodometric overlay method in detection of ESBL production...
January 18, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28098973/electrochemiluminescence-detection-of-escherichia-coli-o157-h7-based-on-a-novel-polydopamine-surface-imprinted-polymer-biosensor
#14
Shufan Chen, Xueqian Chen, Lijuan Zhang, Juanjuan Gao, Qiang Ma
In this paper, a facilely prepared electrochemiluminescence (ECL) biosensor was developed for Escherichia coli (E. coli) O157:H7 quantitative detection based on polydopamine (PDA) surface imprinted polymer (SIP) and nitrogen-doped graphene quantum dots (N-GQDs). N-GQDs with a high quantum yield of 43.2% were synthesized. The uniform PDA SIP film for E. coli O157:H7 was established successfully with a facile route. The dopamine and E. coli O157:H7 were mixed and electropolymerized directly on the electrode. After removed E...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28098806/antibacterial-activities-and-possible-modes-of-action-of-acacia-nilotica-l-del-against-multidrug-resistant-escherichia-coli-and-salmonella
#15
Muhammad Bilal Sadiq, Joel Tarning, Tay Zar Aye Cho, Anil Kumar Anal
Medicinal plants are frequently used for the treatment of various infectious diseases. The objective of this study was to evaluate the antibacterial activity and mode of action of Acacia nilotica and the antibiogram patterns of foodborne and clinical strains of Escherichia coli and Salmonella. The mechanism of action of acacia extracts against E. coli and Salmonella was elucidated by observing morphological damages including cell integrity and cell membrane permeability, as well as changes in cell structures and growth patterns in kill-time experiments...
January 14, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28098790/synthesis-structure-and-antimicrobial-properties-of-novel-benzalkonium-chloride-analogues-with-pyridine-rings
#16
Bogumił Brycki, Izabela Małecka, Anna Koziróg, Anna Otlewska
Quaternary ammonium compounds (QACs) are a group of compounds of great economic significance. They are widely used as emulsifiers, detergents, solubilizers and corrosion inhibitors in household and industrial products. Due to their excellent antimicrobial activity QACs have also gained a special meaning as antimicrobials in hospitals, agriculture and the food industry. The main representatives of the microbiocidal QACs are the benzalkonium chlorides (BACs), which exhibit biocidal activity against most bacteria, fungi, algae and some viruses...
January 13, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28098447/the-stories-tryptophans-tell-exploring-protein-dynamics-of-heptosyltransferase-i-from-escherichia-coli
#17
Joy M Cote, Carlos Andres Ramirez-Mondragon, Zarek S Siegel, Daniel Joseph Czyzyk, Jiali Gao, Yuk Yin Sham, Ishita Mukerji, Erika A Taylor
Heptosyltransferase I (HepI) catalyzes the addition of a single L-glycero-β-D-manno-heptose sugar (heptose) onto the membrane incorporated Kdo2-Lipid A as part of the biosynthesis of the core region of lipopolysaccharide (LPS). Gram-negative bacteria with gene knockouts of HepI have reduced virulence with enhanced susceptibility to hydrophobic antibiotics, making design of inhibitors against HepI of interest. Previous studies have shown that HepI protein dynamics are partially rate limiting, and therefore disruption of protein dynamics might provide a new strategy for inhibiting HepI...
January 18, 2017: Biochemistry
https://www.readbyqxmd.com/read/28097817/revisiting-regulation-of-potassium-homeostasis-in-escherichia-coli-the-connection-to-phosphate-limitation
#18
Hannah Schramke, Vera Laermann, Halina E Tegetmeyer, Andreas Brachmann, Kirsten Jung, Karlheinz Altendorf
Two-component signal transduction constitutes the predominant strategy used by bacteria to adapt to fluctuating environments. The KdpD/KdpE system is one of the most widespread, and is crucial for K(+) homeostasis. In Escherichia coli, the histidine kinase KdpD senses K(+) availability, whereas the response regulator KdpE activates synthesis of the high-affinity K(+) uptake system KdpFABC. Here we show that, in the absence of KdpD, kdpFABC expression can be activated via phosphorylation of KdpE by the histidine kinase PhoR...
January 17, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28097633/meropenem-dosing-based-on-a-population-pharmacokinetic-pharmacodynamic-model-in-elderly-patients-with-infection-of-the-lower-respiratory-tract
#19
Qing-Tao Zhou, Bei He, Ning Shen, Ying Liang, Li-Na Sun
BACKGROUND: Meropenem is used for the treatment of severe lower respiratory tract infections (LRTIs) caused by multidrug-resistant Gram-negative bacilli. OBJECTIVE: We evaluated the clinical benefits of a strategy of meropenem dosing based on a population pharmacokinetics/pharmacodynamics (PK/PD) model in elderly patients with an LRTI. METHODS: In this prospective single-center open-label randomized controlled trial, 79 elderly patients with an LRTI caused by Gram-negative bacilli were randomized to a study group (SG) or a control group (CG)...
January 17, 2017: Drugs & Aging
https://www.readbyqxmd.com/read/28097599/biosynthesis-characterization-and-bioactivities-evaluation-of-silver-and-gold-nanoparticles-mediated-by-the-roots-of-chinese-herbal-angelica-pubescens-maxim
#20
Josua Markus, Dandan Wang, Yeon-Ju Kim, Sungeun Ahn, Ramya Mathiyalagan, Chao Wang, Deok Chun Yang
A facile synthesis and biological applications of silver (DH-AgNps) and gold nanoparticles (DH-AuNps) mediated by the aqueous extract of Angelicae Pubescentis Radix (Du Huo) are explored. Du Huo is a medicinal root belonging to Angelica pubescens Maxim which possesses anti-inflammatory, analgesic, and antioxidant properties. The absorption spectra of nanoparticles in varying root extract and metal ion concentration, pH, reaction temperatures, and time were recorded by ultraviolet-visible (UV-Vis) spectroscopy...
December 2017: Nanoscale Research Letters
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