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Meng Chen, Ning Gan, You Zhou, Tianhua Li, Qing Xu, Yuting Cao, Yinji Chen
An ultrasensitive electrochemical aptasensor for simultaneous detection of oxytetracycline (OTC) and kanamycin (KAN) has been developed based on metal ions doped metal organic frame materials (MOFs) as signal tracers and RecJf exonuclease-catalyzed targets recycling amplification. The aptasensor consists of capture beads (the anti-single-stranded DNA Antibody, as anti-ssDNA Ab, labeled on Dynabeads) and nanoscale MOF (NMOF) based signal tracers (simplified as Apts-MNM, the NMOF labeled with metal ions and the aptamers)...
December 1, 2016: Talanta
Gabriel G Arantes de Carvalho, Stalin Kondaveeti, Denise F S Petri, Alexandre M Fioroto, Luiza G R Albuquerque, Pedro V Oliveira
Analytical methods for the determination of rare earth elements (REE) in natural waters by plasma spectrochemical techniques often require sample preparation procedures for analytes preconcentration as well as for removing matrix constituents, that may interfere on the analytical measurements. In the present work, calcium alginate (CA) beads were used for the first time aiming at Ce, La and Nd preconcentration from groundwater samples for further determination by inductively coupled plasma optical emission spectrometry (ICP OES)...
December 1, 2016: Talanta
Seshasailam Venkateswaran, Maria Angélica Luque-González, Mavys Tabraue-Chávez, Mario Antonio Fara, Barbara López-Longarela, Victoria Cano-Cortes, Francisco Javier López-Delgado, Rosario María Sánchez-Martín, Hugh Ilyine, Mark Bradley, Salvatore Pernagallo, Juan José Díaz-Mochón
Over the last decade, circulating microRNAs have received attention as diagnostic and prognostic biomarkers. In particular, microRNA122 has been demonstrated to be an early and more sensitive indicator of drug-induced liver injury than the widely used biomarkers such as alanine aminotransferase and aspartate aminotransferase. Recently, microRNA122 has been used in vitro to assess the cellular toxicity of new drugs and as a biomarker for the development of a rapid test for drug overdose/liver damage. In this proof-of-concept study, we report a PCR-free and label-free detection method that has a limit of detection (3 standard deviations) of 15 fmoles of microRNA122, by integrating a dynamic chemical approach for "Single Nucleobase Labelling" with a bead-based platform (Luminex(®)) thereby, in principle, demonstrating the exciting prospect of rapid and accurate profiling of any microRNAs related to diseases and toxicology...
December 1, 2016: Talanta
Jaleh Esmaeilzadeh, Hossein Nazemiyeh, Maryam Maghsoodi, Farzaneh Lotfipour
Purpose: Psylliumseeds are used in traditional herbal medicine to treat various disorders. Moreover, as a soluble fiber, psyllium has potential to stimulate bacterial growth in digestive system. We aimed to substitute alkali-extractable polysaccharides of psyllium for alginate in beads with second coat of poly-l-lysine to coat Lactobacillus acidophilus. Methods: Beads were prepared using extrusion technique. Poly-l-lysine as second coat was incorporated on optimum alginate/psyllium beads using immersion technique...
September 2016: Advanced Pharmaceutical Bulletin
Dar-Chone Chow, Kacie Rice, Wanzhi Huang, Robert L Atmar, Timothy G Palzkill
The β-lactamase inhibitory protein (BLIP) binds and inhibits a wide range of class A β-lactamases including the TEM-1 β-lactamase (Ki= 0.5 nM), which is widely present in Gram-negative bacteria, and the KPC-2 β-lactamase (Ki= 1.2 nM), which hydrolyzes virtually all clinically useful β-lactam antibiotics. The extent to which the specificity of a protein that binds a broad range of targets can be modified to display narrow specificity was explored in this study by engineering BLIP to bind selectively to KPC-2 β-lactamase...
October 18, 2016: ACS Infectious Diseases
T Zayats, K K Jacobsen, R Kleppe, C P Jacob, S Kittel-Schneider, M Ribasés, J A Ramos-Quiroga, V Richarte, M Casas, N R Mota, E H Grevet, M Klein, J Corominas, J Bralten, T Galesloot, A A Vasquez, S Herms, A J Forstner, H Larsson, G Breen, P Asherson, S Gross-Lesch, K P Lesch, S Cichon, M B Gabrielsen, O L Holmen, C H D Bau, J Buitelaar, L Kiemeney, S V Faraone, B Cormand, B Franke, A Reif, J Haavik, S Johansson
Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable childhood-onset neuropsychiatric condition, often persisting into adulthood. The genetic architecture of ADHD, particularly in adults, is largely unknown. We performed an exome-wide scan of adult ADHD using the Illumina Human Exome Bead Chip, which interrogates over 250 000 common and rare variants. Participants were recruited by the International Multicenter persistent ADHD CollaboraTion (IMpACT). Statistical analyses were divided into 3 steps: (1) gene-level analysis of rare variants (minor allele frequency (MAF)<1%); (2) single marker association tests of common variants (MAF⩾1%), with replication of the top signals; and (3) pathway analyses...
October 18, 2016: Translational Psychiatry
Marton Szigeti, Andras Guttman
N-glycan profiling of therapeutic glycoproteins is essential to ensure the activity and efficacy of these promising new-generation drugs. The N-linked glycan moieties of these entities highly affect circulation half-life, immunogenicity and receptor-binding activity as well as physicochemical and thermal stability properties. In addition, more than half of the biopharmaceuticals are glycoproteins representing multibillion dollar worldwide business, further emphasizing the importance of their analysis. In the biomedical field, on the other hand, revealing disease-related glycan structure alterations holds the promise of the discovery of new biomarkers for early diagnostics...
2017: Methods in Molecular Biology
Carsten Svaneborg, Hossein Ali Karimi-Varzaneh, Nils Hojdis, Frank Fleck, Ralf Everaers
We present an effective and simple multiscale method for equilibrating Kremer Grest model polymer melts of varying stiffness. In our approach, we progressively equilibrate the melt structure above the tube scale, inside the tube and finally at the monomeric scale. We make use of models designed to be computationally effective at each scale. Density fluctuations in the melt structure above the tube scale are minimized through a Monte Carlo simulated annealing of a lattice polymer model. Subsequently the melt structure below the tube scale is equilibrated via the Rouse dynamics of a force-capped Kremer-Grest model that allows chains to partially interpenetrate...
September 2016: Physical Review. E
Hongjun Chen, Zicheng Yu, Zhijuan Cao, Choiwan Lau
Magnetic bead (MB)-based chemiluminescence (CL) ELISA can be a sample-thrifty, time-saving tool for evaluation of cigarette smoke-induced DNA single-strand breaks (SSBs) with high specificity. This article describes a novel approach using immobilized oligonucleotide on MBs to determine cigarette smoke-induced DNA SSBs and screen some protective natural compounds. Typically, fluorescein-labeled DNA (FAM-DNA) was immobilized on the MBs and then oxidized by the smoke in the absence or presence of natural compounds, and a part of FAM-DNA was fragmented due to cigarette smoke-induced DNA SSB and then detached from MBs whereas other non-broken FAM-DNA still remained on MBs...
October 11, 2016: Analytical and Bioanalytical Chemistry
M Tarasev, M Muchnik, L Light, K Alfano, S Chakraborty
Hemoglobin S (Hb-S) polymerization is the primary event in sickle cell disease causing irreversible damage to red blood cell (RBC) membranes over repeated polymerization cycles. A single polymerization triggered by a hypoxic environment was reported to result in reversibly (upon reoxygenation) decreased RBC deformability and increased mechanical fragility (MF). Individualized responses have not been reported, although RBC fragility can vary significantly even among healthy individuals. This study evaluates individual variability in response to a single hypoxia-induced sickling event, through changes in RBC MF...
September 23, 2016: Translational Research: the Journal of Laboratory and Clinical Medicine
Patrick Gerard Lafond, Sergei Izvekov
An extension of the multiscale coarse-graining method (MS-CG) to polarizable coarse-grained (CG) models is presented. In the extension, force matching is used to derive charged dimers that mimic the dipole behavior, including electronic polarizability, of fine resolution systems. The extended MS-CG method separates short-range and electrostatic forces, and treats the polarization interactions by representing dipole fluctuations with a harmonic bond reminiscent of the Drude oscillator. The new method is first tested on several flexible alcohols, where the transferable head groups in the atomistic field lead to transferable electrostatics in the CG field...
October 11, 2016: Journal of Chemical Theory and Computation
Nathalie Bolduc, Alisa P Lehman, Andrew Farmer
Chromatin immunoprecipitation (ChIP) followed by high-throughput sequencing (ChIP-seq) has become the gold standard for mapping of transcription factors and histone modifications throughout the genome. However, for ChIP experiments involving few cells or targeting low-abundance transcription factors, the small amount of DNA recovered makes ligation of adapters very challenging. In this unit, we describe a ChIP-seq workflow that can be applied to small cell numbers, including a robust single-tube and ligation-free method for preparation of sequencing libraries from sub-nanogram amounts of ChIP DNA...
October 10, 2016: Current Protocols in Molecular Biology
Jorge Malheiro, Sandra Tafulo, Leonídio Dias, La Salete Martins, Isabel Fonseca, Idalina Beirão, António Castro-Henriques, António Cabrita
Detrimental impact of preformed donor-specific antibodies (DSA) against human leukocyte antigens on outcomes after kidney transplantation remains controversial. We aimed to study DSA characteristics (strength and C1q-binding) that might distinguish harmful DSA from clinically irrelevant ones. We retrospectively studied 60 kidney-transplanted patients with preformed DSA detected by single antigen beads (SAB) assays (IgG and C1q kits). Patients were divided both by DSA strength (MFI < vs. ≥15000) and C1q-binding ability...
October 7, 2016: Transplant International: Official Journal of the European Society for Organ Transplantation
Firoozeh Babayekhorasani, Dave E Dunstan, Ramanan Krishnamoorti, Jacinta C Conrad
We identify distinct mechanisms controlling slowing of nanoparticle diffusion through complex media featuring both rigid geometrical confinement and soft mobile crowders. Towards this end, we use confocal microscopy and single particle tracking to probe the diffusion of 400 nm nanoparticles suspended in Newtonian water, in a Newtonian glycerol/water mixture, or in a non-Newtonian polymer solution through a model porous medium, a packed bed of microscale glass beads. The mobility of nanoparticles, as quantified by the long-time diffusion coefficient extracted from the particle mean-squared displacement, slows as the average pore size of the packed bed media decreases for both Newtonian and non-Newtonian solutions...
October 12, 2016: Soft Matter
Danijela Gregurec, Susana Velasco-Lozano, Sergio E Moya, Luis Vázquez, Fernando López-Gallego
Optimal immobilization of enzymes on porous microbeads enables the fabrication of highly active and stable heterogeneous biocatalysts to implement biocatalysis in synthetic and analytical chemistry. However, empirical procedures for enzyme immobilization still prevail over rational ones because there is an unmet need for more comprehensive characterization techniques that aid to understand and trace the immobilization process. Here, we present the use of atomic force spectroscopy (AFS) as an innovative solution to indirectly characterize immobilized proteins on porous materials and monitor the immobilization process in real time...
October 6, 2016: Soft Matter
Roozbeh Abedini-Nassab, Daniel Y Joh, Faris Albarghouthi, Ashutosh Chilkoti, David M Murdoch, Benjamin B Yellen
The ability to direct and sort individual biological and non-biological particles into spatially addressable locations is fundamentally important to the emerging field of single cell biology. Towards this goal, we demonstrate a new class of magnetophoretic transistors, which can switch single magnetically labeled cells and magnetic beads between different paths in a microfluidic chamber. Compared with prior work on magnetophoretic transistors driven by a two-dimensional in-plane rotating field, the addition of a vertical magnetic field bias provides significant advantages in preventing the formation of particle clumps and in better replicating the operating principles of circuits in general...
October 18, 2016: Lab on a Chip
Huning Jia, Ying Bu, Bingjie Zou, Jianping Wang, Shalen Kumar, Janet L Pitman, Guohua Zhou, Qinxin Song
Micro ribose nucleic acids (miRNAs) play an important role in biological processes such as cell differentiation, proliferation and apoptosis. Therefore, miRNAs are potentially a powerful marker for monitoring cancer and diagnosis. Here, we present sensitive signal amplification for miRNAs based on modified cycling probe technology with strand displacement amplification. miRNA was captured by the template coupled with beads, and then the first cycle based on SDA was repeatedly extended to the nicking end, which was produced by the extension reaction of miRNA...
September 30, 2016: Analyst
Mahesh D Patil, Gopal Patel, Balaji Surywanshi, Naeem Shaikh, Prabha Garg, Yusuf Chisti, Uttam Chand Banerjee
Disruption of Pseudomonas putida KT2440 by high-pressure homogenization in a French press is discussed for the release of arginine deiminase (ADI). The enzyme release response of the disruption process was modelled for the experimental factors of biomass concentration in the broth being disrupted, the homogenization pressure and the number of passes of the cell slurry through the homogenizer. For the same data, the response surface method (RSM), the artificial neural network (ANN) and the support vector machine (SVM) models were compared for their ability to predict the performance parameters of the cell disruption...
December 2016: AMB Express
Chien-Shun Yan, Yao-Nan Wang
A multi-parameter optofluidic cytometer based on two low-cost commercial photovoltaic cells and an avalanche photodetector is proposed. The optofluidic cytometer is fabricated on a polydimethylsiloxane (PDMS) substrate and is capable of detecting side scattered (SSC), extinction (EXT) and fluorescence (FL) signals simultaneously using a free-space light transmission technique without the need for on-chip optical waveguides. The feasibility of the proposed device is demonstrated by detecting fluorescent-labeled polystyrene beads with sizes of 3 μm, 5 μm and 10 μm, respectively, and label-free beads with a size of 7...
September 1, 2016: Biomedical Optics Express
Iain C Macaulay, Mabel J Teng, Wilfried Haerty, Parveen Kumar, Chris P Ponting, Thierry Voet
Parallel sequencing of a single cell's genome and transcriptome provides a powerful tool for dissecting genetic variation and its relationship with gene expression. Here we present a detailed protocol for G&T-seq, a method for separation and parallel sequencing of genomic DNA and full-length polyA(+) mRNA from single cells. We provide step-by-step instructions for the isolation and lysis of single cells; the physical separation of polyA(+) mRNA from genomic DNA using a modified oligo-dT bead capture and the respective whole-transcriptome and whole-genome amplifications; and library preparation and sequence analyses of these amplification products...
November 2016: Nature Protocols
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