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https://www.readbyqxmd.com/read/28103015/antimicrobial-activity-ame-resistance-and-translation-inhibition-studies-of-anthraquinone-neomycin-conjugates
#1
Natalya N Degtyareva, Changjun Gong, Sandra Story, Nathanael Levinson, Adegboyega K Oyelere, Keith D Green, Sylvie Garneau-Tsodikova, Dev Priya Arya
The antibacterial effects of aminoglycosides are based on their association with the A-site of bacterial ribosomal RNA and interference with the translational process in the bacterial cell, causing cell death. The clinical use of aminoglycosides is complicated by resistance and side effects, some of which arise from their interactions with the human mitochondrial 12S rRNA and its deafness-associated mutations, C1494U and A1555G. We report a rapid assay that allows screening of aminoglycoside compounds to these classes of rRNAs...
January 19, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/28103008/quantitative-tracking-of-combinatorially-engineered-populations-with-multiplexed-binary-assemblies
#2
Ramsey Zeitoun, Gur Pines, William C Grau, Ryan T Gill
Advances in synthetic biology and genomics have enabled full-scale genome engineering efforts on laboratory timescales. However, the absence of sufficient approaches for mapping engineered genomes at system-wide scales onto performance has limited the adoption of more sophisticated algorithms for engineering complex biological systems. Here we report on the development and application of a robust approach to quantitatively map combinatorially engineered populations at scales up to several dozen target sites...
January 19, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28103007/glutamate-350-plays-an-essential-role-in-conformational-gating-of-long-range-radical-transport-in-e-coli-class-ia-ribonucleotide-reductase
#3
Kanchana R Ravichandran, Ellen C Minnihan, Qinghui Lin, Kenichi Yokoyama, Alexander T Taguchi, Jimin Shao, Daniel G Nocera, JoAnne Stubbe
E. coli Ia ribonucleotide reductase is composed of two subunits that form an active α2β2 complex. The nucleoside diphosphate substrates (NDP) are reduced in α2, 35 Å from the essential diferric-tyrosyl radical (Y122•) cofactor in β2. The Y122• mediated oxidation of C439 in α2 occurs by a pathway (Y122 ↔ [W48] ↔ Y356 in β2 to Y731 ↔ Y730 ↔ C439 in α2) across the α/β interface. The absence of an α2β2 structure precludes insight into the location of Y356 and Y731 at the subunit interface...
January 19, 2017: Biochemistry
https://www.readbyqxmd.com/read/28102569/human-%C3%AE-defensin-3-increases-the-tlr9-dependent-response-to-bacterial-dna
#4
Sarah L McGlasson, Fiona Semple, Heather MacPherson, Mohini Gray, Donald J Davidson, Julia R Dorin
Human β-defensin 3 (hBD3) is a cationic antimicrobial peptide with potent bactericidal activity in vitro. HBD3 is produced in response to pathogen challenge and can modulate immune responses. The amplified recognition of self-DNA by human plasmacytoid dendritic cells has been previously reported, but we show here that hBD3 preferentially enhances the response to bacterial DNA in mouse Flt-3 induced dendritic cells (FLDCs) and in human peripheral blood mononuclear cells. We show the effect is mediated through TLR9 and although hBD3 significantly increases the cellular uptake of both E...
January 19, 2017: European Journal of Immunology
https://www.readbyqxmd.com/read/28102518/quercetin-glucoside-production-by-engineered-escherichia-coli
#5
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/28102367/interspecies-cathelicidin-comparison-reveals-divergence-in-antimicrobial-activity-tlr-modulation-chemokine-induction-and-regulation-of-phagocytosis
#6
Maarten Coorens, Maaike R Scheenstra, Edwin J A Veldhuizen, Henk P Haagsman
Cathelicidins are short cationic peptides initially described as antimicrobial peptides, which can also modulate the immune system. Because most findings have been described in the context of human LL-37 or murine CRAMP, or have been investigated under varying conditions, it is unclear which functions are cathelicidin specific and which functions are general cathelicidin properties. This study compares 12 cathelicidins from 6 species under standardized conditions to better understand the conservation of cathelicidin functions...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28102224/optimality-and-sub-optimality-in-a-bacterial-growth-law
#7
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/28101874/bioengineered-collagens
#8
Barbara Brodsky, John A M Ramshaw
There is a great deal of interest in obtaining recombinant collagen as an alternative source of material for biomedical applications and as an approach for obtaining basic structural and biological information. However, application of recombinant technology to collagen presents challenges, most notably the need for post-translational hydroxylation of prolines for triple-helix stability. Full length recombinant human collagens have been successfully expressed in cell lines, yeast, and several plant systems, while collagen fragments have been expressed in E...
2017: Sub-cellular Biochemistry
https://www.readbyqxmd.com/read/28101682/synthesis-spectral-and-extended-spectrum-beta-lactamase-studies-of-transition-metal-tetraaza-macrocyclic-complexes
#9
Dinesh Kumar, Nutan Sharma, Manjula Nair
Urinary tract infections commonly occur in humans due to microbial pathogens invading the urinary tract, which can bring about a range of clinical symptoms and potentially fatal sequelae. The present study is aimed at addressing the development of a new antimicrobial agent against extended spectrum beta lactamase (ESBL) producing E. coli bacteria. We have synthesised some biologically potent (NNNN) donor macrocycles (L 1  = dibenzo[f,n]dipyrido[3,4-b:4',3'-j][1,4,9,12]tetraazacyclohexadecine-6,11,18,23(5H,12H, 7H, 24H)-tetraone, and L 2  = 6,12,19,25-tetraoxo-4,6,11,12,16,18,23,24-octahydrotetrabenzo [b,g,k,p][1,5,10,14]tetra azacyclooctadecine-2,13-dicarboxylic acid) and their Ti and Zr metal complexes in alcoholic media using microwave protocol...
January 18, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28101156/clinical-and-microbiological-profile-of-babies-born-with-risk-of-neonatal-sepsis
#10
Bin Zhou, Xiao Liu, Jie-Bin Wu, Bao Jin, Yan-Yan Zhang
The aim of the present study was to evaluate the effects of antibiotics on the condition of babies born with risk of neonatal sepsis. From March, 2014 to February, 2015, 200 neonates born with risk factors of septicemia in the Neonatal Intensive Care Unit at Xuzhou Central Hospital, were enrolled in the present study. Venous blood samples were collected within 6 h of birth using aseptic technique. Part of the blood specimens were cultured using BACTEC PEDS PLUS/F Culture Vials. Subsequently, the subcultures were prepared from each presumptive positive vial and bacterial isolates were identified...
December 2016: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/28100961/auxin-extraction-and-purification-based-on-recombinant-aux-iaa-proteins
#11
Yi Su, Weigui Luo, Xiaofei Chen, Huizhen Liu, Yueqing Hu, Wanhuang Lin, Langtao Xiao
BACKGROUND: Indole-3-acetic acid (IAA) extraction and purification are of great importance in auxin research, which is a hot topic in the plant growth and development field. Solid-phase extraction (SPE) is frequently used for IAA extraction and purification. However, no IAA-specific SPE columns are commercially available at the moment. Therefore, the development of IAA-specific recognition materials and IAA extraction and purification methods will help researchers meet the need for more precise analytical methods for research on phytohormones...
2017: Biological Procedures Online
https://www.readbyqxmd.com/read/28100677/paired-siglec-receptors-generate-opposite-inflammatory-responses-to-a-human-specific-pathogen
#12
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
#13
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
#14
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
#15
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/28100049/cell-free-translation-is-more-variable-than-transcription
#16
Fabio Chizzolini, Michele Forlin, Noël Yeh Martín, Giuliano Berloffa, Dario Cecchi, Sheref S Mansy
Although RNA synthesis can be reliably controlled with different T7 transcriptional promoters during cell-free gene expression with the PURE system, protein synthesis remains largely unaffected. To better control protein levels, a series of ribosome binding sites (RBS) was investigated. While RBS strength did strongly affect protein synthesis, the RBS sequence could explain less than half of the variability of the data. Protein expression was found to depend on other factors besides the strength of the RBS, including GC content...
January 19, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28099529/a-possible-role-of-the-full-length-nascent-protein-in-post-translational-ribosome-recycling
#17
Debasis Das, Dibyendu Samanta, Arpita Bhattacharya, Arunima Basu, Anindita Das, Jaydip Ghosh, Abhijit Chakrabarti, Chanchal Das Gupta
Each cycle of translation initiation in bacterial cell requires free 50S and 30S ribosomal subunits originating from the post-translational dissociation of 70S ribosome from the previous cycle. Literature shows stable dissociation of 70S from model post-termination complexes by the concerted action of Ribosome Recycling Factor (RRF) and Elongation Factor G (EF-G) that interact with the rRNA bridge B2a/B2b joining 50S to 30S. In such experimental models, the role of full-length nascent protein was never considered seriously...
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
#18
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
#19
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
#20
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
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