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https://www.readbyqxmd.com/read/28098301/optical-dna-mapping-in-nanofluidic-devices-principles-and-applications
#1
Vilhelm Müller, Fredrik Westerlund
Optical DNA mapping has over the last decade emerged as a very powerful tool for obtaining long range sequence information from single DNA molecules. In optical DNA mapping, intact large single DNA molecules are labeled, stretched out, and imaged using a fluorescence microscope. This means that sequence information ranging over hundreds of kilobasepairs (kbp) can be obtained in one single image. Nanochannels offer homogeneous and efficient stretching of DNA that is crucial to maximize the information that can be obtained from optical DNA maps...
January 18, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28098202/superresolution-imaging-of-clinical-formalin-fixed-paraffin-embedded-breast-cancer-with-single-molecule-localization-microscopy
#2
Matthew K Creech, Jing Wang, Xiaolin Nan, Summer L Gibbs
Millions of archived formalin-fixed, paraffin-embedded (FFPE) specimens contain valuable molecular insight into healthy and diseased states persevered in their native ultrastructure. To diagnose and treat diseases in tissue on the nanoscopic scale, pathology traditionally employs electron microscopy (EM), but this platform has significant limitations including cost and painstaking sample preparation. The invention of single molecule localization microscopy (SMLM) optically overcame the diffraction limit of light to resolve fluorescently labeled molecules on the nanoscale, leading to many exciting biological discoveries...
January 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28094505/self-assembly-and-disassembly-of-amphiphilic-zwitterionic-perylenediimide-vesicles-for-cell-membrane-imaging
#3
Yong Ye, Yang Zheng, Chendong Ji, Jie Shen, Meizhen Yin
Animal cells have complicated dynamics of cell membrane structures which require desirable dyes to in vivo imaging. Here, an asymmetric amphiphilic zwitterionic perylenediimide (ZP) has been constructed by introducing an octyl chain and a zwitterionic head to each imide position of perylenediimide chromophore. ZP can self-assemble into vesicles in aqueous solution. The aggregated ZP vesicles have been explored to image cell inner or surface membrane structures by controlled disassembly process. The ZP vesicles, when are uptaken into cells, disassemble into single molecules and incorporate into cell inner membranes...
January 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28094402/mesoporous-carbon-nanoshells-for-high-hydrophobic-drug-loading-multimodal-optical-imaging-controlled-drug-release-and-synergistic-therapy
#4
Hui Wang, Kui Wang, Qingxin Mu, Zachary R Stephen, Yanyan Yu, Shuiqin Zhou, Miqin Zhang
Loading and controlled release of sufficient hydrophobic drugs to tumor cells has been the bottleneck in chemotherapy for decades. Herein we report the development of a fluorescent and mesoporous carbon nanoshell (FMP-CNS) that exhibits a loading capacity for the hydrophobic drug paclitaxel (PTX) as high as ∼80 wt% and releases the drug in a controllable fashion under NIR irradiation (825 nm) at an intensity of 1.5 W cm(-2). The high drug loading is primarily attributed to its mesoporous structure and to the supramolecular π-stacking between FMP-CNSs and PTX molecules...
January 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/28091541/apelin-receptor-homodimer-oligomers-revealed-by-single-molecule-imaging-and-novel-g-protein-dependent-signaling
#5
Xin Cai, Bo Bai, Rumin Zhang, Chunmei Wang, Jing Chen
The apelin receptor (APJ) belongs to family A of the G protein-coupled receptors (GPCRs) and is a potential pharmacotherapeutic target for heart failure, hypertension, and other cardiovascular diseases. There is evidence APJ heterodimerizes with other GPCRs; however, the existence of APJ homodimers and oligomers remains to be investigated. Here, we measured APJ monomer-homodimer-oligomer interconversion by monitoring APJ dynamically on cells and compared their proportions, spatial arrangement, and mobility using total internal reflection fluorescence microscopy, resonance energy transfer, and proximity biotinylation...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28087691/imaging-proteins-at-the-single-molecule-level
#6
Jean-Nicolas Longchamp, Stephan Rauschenbach, Sabine Abb, Conrad Escher, Tatiana Latychevskaia, Klaus Kern, Hans-Werner Fink
Imaging single proteins has been a long-standing ambition for advancing various fields in natural science, as for instance structural biology, biophysics, and molecular nanotechnology. In particular, revealing the distinct conformations of an individual protein is of utmost importance. Here, we show the imaging of individual proteins and protein complexes by low-energy electron holography. Samples of individual proteins and protein complexes on ultraclean freestanding graphene were prepared by soft-landing electrospray ion beam deposition, which allows chemical- and conformational-specific selection and gentle deposition...
January 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28080023/microbial-nanoscopy-breakthroughs-challenges-and-opportunities
#7
Yves F Dufrêne
Studying the structure, properties, and interactions of microbial cells is key to understanding the functions of the microbiome. Recent advances in nanotechnology have offered new tools to probe microbes at the single-molecule and single-cell levels. In this issue of ACS Nano, Kumar et al. present an atomic force microscopy method that is capable of imaging the nanoscale organization of bacterial proteins in native, curved membranes. This study represents an important step forward in the development of nanoscopy techniques for analyzing biological systems with large curvature and vertical dimensions, such as membrane vesicles and bacterial cells...
January 12, 2017: ACS Nano
https://www.readbyqxmd.com/read/28078590/quantifying-cd95-cl-cd95l-implications-in-cell-mechanics-and-membrane-tension-by-atomic-force-microscopy-based-force-measurements
#8
Anaïs Sadoun, Pierre-Henri Puech
Atomic force microscopy (AFM) is an invaluable tool to investigate the structure of biological material surfaces by imaging them at nanometer scale in physiological conditions. It can also be used to measure the forces and mechanics from single molecule interaction to cell-cell adhesion. Here, we present a methodology that allows to quantify cell elastic properties (using the Young modulus) and cell membrane tension modulated by CD95/cl-CD95L interactions by coupling nanoindentation and membrane tube pulling using suitably decorated AFM levers...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28077620/mitogen-induced-distinct-epi-alleles-are-phosphorylated-at-either-h3s10-or-h3s28-depending-on-h3k27-acetylation
#9
Dilshad H Khan, Shannon Healy, Shihua He, Daniel Lichtensztejn, Ludger Klewes, Kiran L Sharma, Veronica Lau, Sabine Mai, Geneviève P Delcuve, James R Davie
Stimulation of the MAPK pathway results in mitogen- and stress-activated protein kinase 1/2 (MSK1/2)-catalyzed phosphorylation of histone H3 at serine 10 or 28 and expression of immediate-early (IE) genes. In 10T1/2 mouse fibroblasts, phosphorylation of H3S10 and H3S28 occurs on different H3 molecules and in different nuclear regions. Likewise, we show that mitogen-induced H3S10 and H3S28 phosphorylation occurs in separate pools in human primary fibroblasts. High-resolution imaging studies on both cell types have revealed that H3S10 and H3S28 phosphorylation events can be induced in a single cell but on different alleles, giving rise to H3S10ph and H3S28ph epi-alleles...
January 11, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28076939/is-there-still-room-for-novelty-in-histochemical-papers
#10
Carlo Pellicciari
Histochemistry continues to be widely applied in biomedical research, being nowadays mostly addressed to detect and locate single molecules or molecular complexes inside cells and tissues, and to relate structural organization and function at the high resolution of the more advanced microscopical techniques. In the attempt to see whether histochemical novelties may be found in the recent literature, the articles published in the European Journal of Histochemistry in the period 2014-2016 have been reviewed. In the majority of the published papers, standardized methods have been preferred by scientists to make their results reliably comparable with the data in the literature, but  many papers (approximately one fourth of the published articles) described novel histochemical methods and procedures...
December 16, 2016: European Journal of Histochemistry: EJH
https://www.readbyqxmd.com/read/28074942/chemistry-at-the-square-nanometer-reactivity-at-liquid-solid-interfaces-revealed-with-an-stm
#11
Joris A W Münninghoff, Johannes A A W Elemans
For more than three decades the scanning tunnelling microscope (STM) has proven to be an indispensable tool to image molecules adsorbed at a surface at the highest detail possible. In addition to simply imaging molecules, STM can also be applied to monitor dynamic surface phenomena, including chemical reactions. By studying reactions at a surface at the single molecule level, unique information about reaction mechanisms can be obtained which remains hidden when conventional ensemble techniques are used. Many STM studies of chemical reactions have been performed in extreme environments like ultrahigh vacuum or high pressure chambers, but these are far removed from conditions in which most chemical and biological processes take place, i...
January 11, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28074833/shifting-molecular-localization-by-plasmonic-coupling-in-a-single-molecule-mirage
#12
Mario Raab, Carolin Vietz, Fernando Daniel Stefani, Guillermo Pedro Acuna, Philip Tinnefeld
Over the last decade, two fields have dominated the attention of sub-diffraction photonics research: plasmonics and fluorescence nanoscopy. Nanoscopy based on single-molecule localization offers a practical way to explore plasmonic interactions with nanometre resolution. However, this seemingly straightforward technique may retrieve false positional information. Here, we make use of the DNA origami technique to both control a nanometric separation between emitters and a gold nanoparticle, and as a platform for super-resolution imaging based on single-molecule localization...
January 11, 2017: Nature Communications
https://www.readbyqxmd.com/read/28073939/nanoscale-molecular-reorganization-of-the-inhibitory-postsynaptic-density-is-a-determinant-of-gabaergic-synaptic-potentiation
#13
Francesca Pennacchietti, Sebastiano Vascon, Thierry Nieus, Christian Rosillo, Sabyasachi Das, Shiva Tyagarajan, Alberto Diaspro, Alessio Del Bue, Enrica Maria Petrini, Andrea Barberis, Francesca Cella Zanacchi
: Gephyrin is a key scaffold protein mediating the anchoring of GABAA receptors at inhibitory synapses. Here we exploited super-resolution techniques combined with proximity-based clustering analysis and model simulations to investigate the single molecule gephyrin reorganization during plasticity of inhibitory synapses in mouse hippocampal cultured neurons. This approach revealed that during the expression of inhibitory long-term potentiation the increase of gephyrin density at postsynaptic sites is associated with the promoted formation of gephyrin nano-domains...
January 10, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28071667/photogate-microscopy-to-track-single-molecules-in-crowded-environments
#14
Vladislav Belyy, Sheng-Min Shih, Jigar Bandaria, Yongjian Huang, Rosalie E Lawrence, Roberto Zoncu, Ahmet Yildiz
Tracking single molecules inside cells reveals the dynamics of biological processes, including receptor trafficking, signalling and cargo transport. However, individual molecules often cannot be resolved inside cells due to their high density. Here we develop the PhotoGate technique that controls the number of fluorescent particles in a region of interest by repeatedly photobleaching its boundary. PhotoGate bypasses the requirement of photoactivation to track single particles at surface densities two orders of magnitude greater than the single-molecule detection limit...
January 10, 2017: Nature Communications
https://www.readbyqxmd.com/read/28070848/intravaginal-delivery-of-polyphenon-60-and-curcumin-nanoemulsion-gel
#15
Atinderpal Kaur, Yashaswee Saxena, Rakhi Bansal, Sonal Gupta, Amit Tyagi, Rakesh Kumar Sharma, Javed Ali, Amulya Kumar Panda, Reema Gabrani, Shweta Dang
Polyphenon 60 (P60) and curcumin (CUR) were loaded in a single nanoemulsion system and their combined antibacterial action was studied against uropathogenic Escherichia coli. To enhance availability at target organs and to inhibit enzymatic degradation in gastro intestinal tract, vaginal route of administration was explored. P60 + CUR nanoemulsion (NE) was formulated by ultra-sonication and optimized using Box-Behnken design. Optimized NE showed Z-average of 211.2 nm, polydispersity index of 0.343, and zeta potential of -32...
January 9, 2017: AAPS PharmSciTech
https://www.readbyqxmd.com/read/28069541/a-bispecific-tribody-pet-radioligand-for-visualization-of-amyloid-beta-protofibrils-a-new-concept-for-neuroimaging
#16
Stina Syvänen, Xiaotian T Fang, Greta Hultqvist, Silvio R Meier, Lars Lannfelt, Dag Sehlin
Antibodies are highly specific for their target molecules, but their poor brain penetrance has restricted their use as PET ligands for imaging of targets within the CNS. The aim of this study was to develop an antibody-based radioligand, using the Tribody(TM) format, for PET imaging of soluble amyloid-beta (Aβ) protofibrils, which are suggested to cause neurodegeneration in Alzheimer's disease. Antibodies, even when expressed in smaller engineered formats, are large molecules that do not enter the brain in sufficient amounts for imaging purposes...
January 6, 2017: NeuroImage
https://www.readbyqxmd.com/read/28068671/high-spatial-resolution-mapping-of-catalytic-reactions-on-single-particles
#17
Chung-Yeh Wu, William J Wolf, Yehonatan Levartovsky, Hans A Bechtel, Michael C Martin, F Dean Toste, Elad Gross
The critical role in surface reactions and heterogeneous catalysis of metal atoms with low coordination numbers, such as found at atomic steps and surface defects, is firmly established. But despite the growing availability of tools that enable detailed in situ characterization, so far it has not been possible to document this role directly. Surface properties can be mapped with high spatial resolution, and catalytic conversion can be tracked with a clear chemical signature; however, the combination of the two, which would enable high-spatial-resolution detection of reactions on catalytic surfaces, has rarely been achieved...
January 11, 2017: Nature
https://www.readbyqxmd.com/read/28067380/a-single-light-triggered-and-dual-imaging-guided-multifunctional-platform-for-combined-photothermal-and-photodynamic-therapy-based-on-td-controlled-and-icg-loaded-cus-msio2
#18
Qing You, Qi Sun, Jinping Wang, Xiaoxiao Tan, Xiaojuan Pang, Li Liu, Meng Yu, Fengping Tan, Nan Li
Near-infrared (NIR)-responsive drug delivery systems have received enormous attention because of their good biocompatibility and high biological penetration. In this work, we report a novel 1-tetradecanol (TD)-controlled and indocyanine green (ICG)-loaded CuS@mSiO2 phototherapy nanoplatform (CuS@mSiO2-TD/ICG). The CuS@mSiO2 nanoparticles prepared by a facile one-pot approach can serve as drug-delivery vehicles to transport the NIR absorbing phototherapeutic agent (ICG) within the mesoporous cavities. Meanwhile a phase-change molecule (PCM), TD, is introduced as a thermosensitive gatekeeper to avoid the premature release of loaded ICG...
January 9, 2017: Nanoscale
https://www.readbyqxmd.com/read/28067372/selective-turn-on-and-modulation-of-resonant-energy-transfer-in-single-plasmonic-hybrid-nanostructures
#19
Łukasz Bujak, Tatsuya Ishii, Dharmendar Kumar Sharma, Shuzo Hirata, Martin Vacha
Förster resonant energy transfer (FRET) is a nonradiative process by which the energy of light absorbed by a donor molecule is transferred to an acceptor molecule over a distance of several nanometers. FRET plays a crucial role in photosynthesis and nature-inspired artificial light-harvesting systems that are being explored for use in energy conversion applications. Localized plasmons of metal nanoparticles can potentially lead to a significant increase of FRET efficiency and effective donor-acceptor distance...
January 9, 2017: Nanoscale
https://www.readbyqxmd.com/read/28067252/two-step-amyloid-aggregation-sequential-lag-phase-intermediates
#20
Fabio Castello, Jose M Paredes, Maria J Ruedas-Rama, Miguel Martin, Mar Roldan, Salvador Casares, Angel Orte
The self-assembly of proteins into fibrillar structures called amyloid fibrils underlies the onset and symptoms of neurodegenerative diseases, such as Alzheimer's and Parkinson's. However, the molecular basis and mechanism of amyloid aggregation are not completely understood. For many amyloidogenic proteins, certain oligomeric intermediates that form in the early aggregation phase appear to be the principal cause of cellular toxicity. Recent computational studies have suggested the importance of nonspecific interactions for the initiation of the oligomerization process prior to the structural conversion steps and template seeding, particularly at low protein concentrations...
January 9, 2017: Scientific Reports
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