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https://www.readbyqxmd.com/read/28820590/conformational-heterogeneity-in-a-fully-complementary-dna-three-way-junction-with-a-gc-rich-branchpoint
#1
Anita Toulmin, Laura E Baltierra-Jasso, Michael J Morten, Tara Sabir, Peter McGlynn, Gunnar F Schröder, Brian O Smith, Steven W Magennis
DNA three-way junctions (3WJs) are branched structures that serve as important biological intermediates and as components in DNA nanostructures. We recently derived the global structure of a fully-complementary 3WJ and found that it contained unpaired bases at the branchpoint, in support of previous observations of branch flexibility and branchpoint reactivity. By combining high-resolution single-molecule FRET, molecular modeling, time-resolved ensemble fluorescence spectroscopy and the first 19F NMR observations of fully complementary 3WJs, we now show that the 3WJ structure can adopt multiple distinct conformations depending upon the sequence at the branchpoint...
August 18, 2017: Biochemistry
https://www.readbyqxmd.com/read/28818574/antimicrobial-resistance-determinants-and-susceptibility-profiles-of-pneumococcal-isolates-recovered-in-trinidad-and-tobago
#2
Paulina A Hawkins, Patrick E Akpaka, Michele Nurse-Lucas, Rebecca Gladstone, Stephen D Bentley, Robert F Breiman, Lesley McGee, William H Swanston
INTRODUCTION: In Latin America and the Caribbean, pneumococcal infections were estimated to account for 12,000-18,000 deaths, 327,000 cases of pneumonia, 4,000 cases of meningitis and 1,229 cases of sepsis each year in children under five years old. Resistance of pneumococci to antimicrobial agents has evolved into a worldwide health problem in the last few decades. OBJECTIVE: The aim of this study was to determine the antimicrobial susceptibility profiles of 98 pneumococcal isolates collected in Trinidad and Tobago and associated genetic determinants...
August 14, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28817670/synthesis-radiosynthesis-and-in-vitro-evaluation-of-18f-bodipy-c16-triglyceride-as-a-dual-modal-imaging-agent-for-brown-adipose-tissue
#3
Andreas Paulus, Marco Maenen, Natascha Drude, Emmani B M Nascimento, Wouter D van Marken Lichtenbelt, Felix M Mottaghy, Matthias Bauwens
BACKGROUND: Brown adipose tissue research is in the focus in the field of endocrinology. We designed a dual-modal fluorescent/PET fatty acid based tracer on commercially available Bodipy-C16, which can be synthesized to its corresponding triglyceride and which combines the benefits of fluorescent and PET imaging. METHODS: Bodipy-C16 was coupled to 1,3-diolein resulting in Bodipy-triglyceride. Bodipy-C16 and Bodipy-triglyceride compounds were radiolabeled with 18F using an 18F/19F exchange reaction to yield a dual-modal imaging molecule...
2017: PloS One
https://www.readbyqxmd.com/read/28783319/sharper-reaction-monitoring-generation-of-a-narrow-line-width-nmr-singlet-without-x-pulses-in-an-inhomogeneous-magnetic-field
#4
Ariana B Jones, Guy C Lloyd-Jones, Dusan Uhrin
We report a new 'pure-shift' method, termed 'SHARPER' (Sensitive, Homogeneous And Resolved PEaks in Real time) de-signed for the analysis of reactions and equilibria by NMR. By focusing on a single selected signal, SHARPER removes all heteronuclear couplings of a selected nucleus without the need to pulse on X channels, thus overcoming hardware limitations of conventional spectrometers. A more versatile decoupling scheme, termed 'sel-SHARPER', removes all heteronuclear and homonuclear couplings of the selected signal...
August 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28780980/impact-of-the-hajj-on-pneumococcal-carriage-and-the-effect-of-various-pneumococcal-vaccines
#5
REVIEW
Sophie Edouard, Jaffar A Al-Tawfiq, Ziad A Memish, Saber Yezli, Philippe Gautret
BACKGROUND: The Islamic Hajj pilgrimage is the largest annual mass gathering in the world. The overcrowding of people promotes the acquisition, spread and transmission of respiratory pathogens, including Streptococcus pneumoniae. It is estimated that about 33% of pilgrims are at risk of invasive pneumococcal disease. METHODS: We conducted a methodological review according to the Preferred Reporting Items for Systematic Reviews and meta-Analysis guidelines. The objective was to summarize the available data regarding the prevalence of pneumococcal carriage among Hajj pilgrims and about carriage acquisition and circulation of S...
August 3, 2017: Vaccine
https://www.readbyqxmd.com/read/28777565/synthesis-and-characterization-of-pegylated-and-fluorinated-chitosans-application-to-the-synthesis-of-targeted-nanoparticles-for-drug-delivery
#6
Yamina Belabassi, Juliette Moreau, Virginia Gheran, Céline Henoumont, Anthony Robert, Maité Callewaert, Guillaume Rigaux, Cyril Cadiou, Luce Vander Elst, Sophie Laurent, Robert N Muller, Anca Dinischiotu, Sorina Nicoleta Voicu, Francoise Chuburu
To synthesize chitosan nanoparticles (CS NPs), ionic gelation is a very attractive method. It relies on the spontaneous supramolecular assembly of cationic CS with anionic compounds, which leads to nanohydrogels. To extend ionic gelation to functionalized CS, the assessment of CS degree of substitution (DSCS) is a key step. In this paper, we have developed a hyphenated strategy for functionalized CS characterization, based upon 1H, DOSY and when relevant, 1D diffusion-filtered 19F NMR spectroscopies. For that, we have synthesized two series of water-soluble CS via amidation of CS amino groups with mPEG2000-COOH or fluorinated synthons (TFB-COOH)...
August 4, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28777560/a-critical-crosscatalytic-relationship-determines-the-outcome-of-competition-in-a-replicator-network
#7
Tamara Kosikova, Douglas Philp
A network of two synthetic replicators exhibits a critical unidirectional crosscatalytic relationship that directs competing replication processes. In this network, nitrone N bearing a 6-methylamidopyridine recognition site can participate in two 1,3-dipolar cycloaddition reactions with two maleimides that differ in the relative position of their carboxylic acid recognition site - either para (Mp) or meta (Mm) relative to the maleimide ring. These two cycloaddition reactions create replicators trans-Tp and trans-Tm...
August 4, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28777495/increased-conformational-flexibility-of-a-macrocycle-receptor-complex-contributes-to-reduced-dissociation-rates
#8
Adrian Glas, Eike-Christian Wamhoff, Dennis M Krüger, Christoph Rademacher, Tom N Grossmann
Constraining a peptide in its bioactive conformation via macrocyclization represents a powerful strategy to design modulators of challenging biomolecular targets. This holds particularly true for the development of inhibitors of protein-protein interactions which often involve interfaces lacking defined binding pockets. Such flat surfaces are demanding targets for traditional small molecules rendering macrocyclic peptides promising scaffolds for novel therapeutics. However, the contribution of peptide dynamics to binding kinetics is barely understood which impedes the design process...
August 4, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28776972/controlled-zn-2-triggered-drug-release-by-preferred-coordination-of-open-active-sites-within-functionalization-indium-metal-organic-frameworks
#9
Xi Du, Ruiqing Fan, Liangsheng Qiang, Kai Xing, Haoxin Ye, Xinya Ran, Yang Song, Ping Wang, Yulin Yang
Drug delivery in target regions could make extraordinary progress in chemoselective therapies. A novel preferred coordination (PC) strategy referring to proactive interacting with open active sites to replace previous occupation by ion-exchange for controlling release of drug molecules is well-constructed. Two topological types of MOF-In1 (Schläfli symbol: (4,8)-connected of (4(10)·6(15)·8(3))(4(5)·6)2) and MOF-In2 (Schläfli symbol: (4,4)-connected of (6(6))) show the specific way. Increasing node connectivity as well as the trapping of guest OH(-) anions, 5-fluorouracil (5-FU) is preferentially captured into the MOF-In1, which exhibits an outstanding loading capacity around 34...
August 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28758387/characterization-of-heme-orientational-disorder-in-a-myoglobin-reconstituted-with-a-trifluoromethyl-group-substituted-heme-cofactor
#10
Yuki Kanai, Ayaka Harada, Tomokazu Shibata, Ryu Nishimura, Kosuke Namiki, Miho Watanabe, Shunpei Nakamura, Fumiaki Yumoto, Toshiya Senda, Akihiro Suzuki, Saburo Neya, Yasuhiko Yamamoto
The orientation of a CF3-substituted heme in sperm whale myoglobin and L29F, H64L, L29F/H64Q, and H64Q variant proteins has been investigated using (19)F NMR spectroscopy to elucidate structural factors responsible for the thermodynamic stability of the heme orientational disorder, i.e., the presence of two heme orientations differing by a 180° rotation about the 5-15 meso axis, with respect to the protein moiety. Crystal structure of the met-aquo form of the wild-type myoglobin reconstituted with 13,17-bis(2-carboxylatoethyl)-3,8-diethyl-2,12,18-trimethyl-7-trifluoromethylporphyrinatoiron(III), determined at resolution of 1...
August 16, 2017: Biochemistry
https://www.readbyqxmd.com/read/28756964/key-features-of-invasive-pneumococcal-isolates-recovered-in-lima-peru-determined-through-whole-genome-sequencing
#11
Paulina Hawkins, Erik Mercado, Sopio Chochua, Maria E Castillo, Isabel Reyes, Eduardo Chaparro, Rebecca Gladstone, Stephen D Bentley, Robert F Breiman, Benjamin J Metcalf, Bernard Beall, Theresa J Ochoa, Lesley McGee
Before PCV7 introduction, invasive pneumococcal disease (IPD) was responsible for approximately 12,000-18,000 deaths annually among children <5years in Latin America. In Peru, PCV7 was introduced in 2009. We used whole genome sequencing to deduce key features of invasive strains collected in Lima, Peru from 2006 to 2011. We sequenced 212 IPD isolates from 16 hospitals in Lima pre (2006-2009; n=133) and post (2010-2011; n=79) PCV7 introduction; 130 (61.3%) isolates were from children≤5years old. CDC's Streptococcus lab bioinformatics pipeline revealed serotypes, sequence types (STs), pilus genes, PBP types and other resistance determinants...
July 22, 2017: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/28753245/selective-19f-labeling-of-functionalized-carboxylic-acids-with-difluoromethyl-diazomethane-cf2hchn2
#12
Pavel Mykhailiuk, Igor Kishko, Volodymyr Kubyshkin, Nediljko Budisa, Janine Cossy
The incorporation of fluorinated moieties into organic structures is a particularly powerful approach for generating compounds with useful biological applications in industry, pharmacology, and agriculture. Herein, we report that the recently developed reagent - CF2HCHN2 - selectively esterifies carboxyl groups in organic molecules possessing other polar functional groups. The reaction is remarkably simple, proceeding at room temperature in chloroform without addition of a catalyst. The procedure allows "last-step" incorporation of a fluorinated ester moiety into organic structures, including bioorganic molecules such as peptides and proteins...
July 28, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28745918/a-systematic-review-about-streptococcus-pneumoniae-serotype-distribution-in-children-in-mainland-of-china-before-the-pcv13-was-licensed
#13
Shuang Lyu, Hui-Li Hu, Yong-Hong Yang, Kai-Hu Yao
Streptococcus pneumoniae (S. pneumoniae) is a major pathogen of infectious diseases in children. Surveillance of the distribution of pneumococcus serotypes is important for immunization strategies of pneumococcal polysaccharide conjugate vaccines (PCVs). Areas covered: This article is a systematic review of studies conducted from 2006 to 2016 that document serotypes of S. pneumoniae isolated from children less than 14 years old in the mainland of China. A total of 40 studies were included in this review. Serotypes 19F, 19A, 23F, 14 and 6B were the most common...
July 26, 2017: Expert Review of Vaccines
https://www.readbyqxmd.com/read/28744663/serotypes-of-streptococcus-pneumoniae-in-egyptian-children-are-they-covered-by-pneumococcal-conjugate-vaccines
#14
M Badawy, A El Kholy, M M Sherif, E A Rahman, E Ashour, H Sherif, H E Mahmoud, M Hamdy
In Egypt, pneumococcal vaccines have not yet been introduced as being compulsory. Identification of the circulating serotypes in Egypt is mandatory to determine whether or not the pneumococcal vaccines will be beneficial. The current study aims to identify the serotypes, vaccine coverage, and antimicrobial resistance of Streptococcus pneumoniae colonizing the nasopharynx of Egyptian children younger than 5 years old. The study was conducted in two successive winter seasons (December 2012-February 2013 and December 2013-February 2014)...
July 25, 2017: European Journal of Clinical Microbiology & Infectious Diseases
https://www.readbyqxmd.com/read/28742232/altering-the-coordination-of-iron-porphyrins-by-ionic-liquid-nanodomains-in-mixed-solvent-systems
#15
Abderrahman Atifi, Michael Ryan
The solvent environment around iron porphyrin complexes was examined using mixed molecular/RTIL (room temperature ionic liquid) solutions. The formation of nanodomains in these solutions provides different solvation environments for substrates that could have significant impact on their chemical reactivity. Iron porphyrins (Fe(P)), whose properties are sensitive to solvent and ligation changes, were used to probe the molecular/RTIL environment. The addition of RTILs to molecular solvents shifted the redox potentials to more positive values...
July 25, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28739116/pneumococcal-conjugate-vaccine-induced-igg-and-nasopharyngeal-carriage-of-pneumococci-hyporesponsiveness-and-immune-correlates-of-protection-for-carriage
#16
John Ojal, Laura L Hammitt, John Gaitho, J Anthony G Scott, David Goldblatt
BACKGROUND: Prior studies have demonstrated hyporesponsiveness to pneumococcal conjugate vaccines (PCVs) when administered in the presence of homologous carriage. This may be substantially more important in Africa where carriage prevalence is high. Deriving a correlate of protection (CoP) for carriage is important in guiding the future use of extended PCVs as population control of pneumococcal disease by vaccination is now focused principally on its indirect effect. We therefore explored the complex relationship between existing carriage and vaccine responsiveness, and between serum IgG levels and risk of acquisition...
June 19, 2017: Vaccine
https://www.readbyqxmd.com/read/28724524/assignment-of-weight-based-antibody-units-for-four-additional-serotypes-to-a-human-anti-pneumococcal-standard-reference-serum-007sp
#17
D Goldblatt, A McKeen, P Burbidge, S McElhiney, L McLaughlin, A Johnson, M Rauh, P C Giardina
The pneumococcal ELISA reference standard serum, Lot 89SF, has been in use since 1990 and was replaced with a new reference standard serum, 007sp in 2013. This serum was generated under an FDA-approved clinical protocol, where 278 adult volunteers were immunized with the 23-valent unconjugated polysaccharide vaccine, Pneumovax II®, and a unit of blood was obtained twice within 120 days following immunization. Pooled serum was prepared from the plasma, filled at 6ml per vial and lyophilised. Five independent laboratories participated in bridging the serotype specific IgG assignments for 89SF to 007sp to establish equivalent reference values for 13 pneumococcal capsular serotypes (1,3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 23F) using the WHO reference ELISA...
July 19, 2017: Clinical and Vaccine Immunology: CVI
https://www.readbyqxmd.com/read/28722296/a-ligand-based-nmr-screening-approach-for-the-identification-and-characterization-of-inhibitors-and-promoters-of-amyloid-peptide-aggregation
#18
Claudio Dalvit, Sara Santi, Reinhard Neier
Over the years a significant amount of effort has been put into the development of rapid and reliable methods to monitor the aggregation dynamics of the β1-42 amyloid peptide in real time. We present an alternative approach based on a suitable reporter or spy molecule and three different NMR experiments: WaterLOGSY, (1) H selective T1 filter, and (19) F T2 filter, for monitoring the initial self-aggregation process kinetics of the β1-42 amyloid peptide and identifying molecules that retard or accelerate the self-aggregation process...
July 19, 2017: ChemMedChem
https://www.readbyqxmd.com/read/28720328/design-synthesis-molecular-modeling-and-anti-hyperglycemic-evaluation-of-quinazolin-4-3h-one-derivatives-as-potential-ppar%C3%AE-and-sur-agonists
#19
Mohamed K Ibrahim, Ibrahim H Eissa, Mohamed S Alesawy, Ahmed M Metwaly, Mohamed M Radwan, Mahmoud A ElSohly
Peroxisome proliferator-activated receptor gamma (PPARγ) and sulfonylurea receptor (SUR) play crucial roles in management of type-2 diabetes mellitus. In this study, a series of novel quinazoline-4(3H)-one-sulfonylurea hybrids were designed and synthesized as dual PPARγ and SUR agonists. The synthesized compounds were evaluated for their in vivo anti-hyperglycemic activities against STZ-induced hyperglycemic rats. Four compounds (19a, 19d, 19f and 25g) demonstrated potent activities with reduction in blood glucose levels of 40...
July 8, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28719195/fluorinated-boronic-acid-appended-pyridinium-salts-and-19-f-nmr-spectroscopy-for-diol-sensing
#20
Jörg Axthelm, Sven H C Askes, Martin Elstner, Upendar Reddy G, Helmar Görls, Peter Bellstedt, Alexander Schiller
The identification and discrimination of diols is of fundamental importance in medical diagnostics, such as measuring the contents of glucose in the urine of diabetes patients. Diol sensors are often based on fluorophore-appended boronic acids, but these severely lack discriminatory power and their response is one-dimensional. As an alternative strategy, we present the use of fluorinated boronic acid-appended pyridinium salts in combination with (19)F NMR spectroscopy. A pool of 59 (bio)analytes was screened, containing monosaccharides, phosphorylated and N-acetylated sugars, polyols, carboxylic acids, nucleotides, and amines...
August 9, 2017: Journal of the American Chemical Society
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