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Single particle electron microscopy

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https://www.readbyqxmd.com/read/27913831/high-transport-efficiency-of-nanoparticles-through-a-total-consumption-sample-introduction-system-and-its-beneficial-application-for-particle-size-evaluation-in-single-particle-icp-ms
#1
Shin-Ichi Miyashita, Hiroaki Mitsuhashi, Shin-Ichiro Fujii, Akiko Takatsu, Kazumi Inagaki, Toshiyuki Fujimoto
In order to facilitate reliable and efficient determination of both the particle number concentration (PNC) and the size of nanoparticles (NPs) by single-particle ICP-MS (spICP-MS) without the need to correct for the particle transport efficiency (TE, a possible source of bias in the results), a total-consumption sample introduction system consisting of a large-bore, high-performance concentric nebulizer and a small-volume on-axis cylinder chamber was utilized. Such a system potentially permits a particle TE of 100 %, meaning that there is no need to include a particle TE correction when calculating the PNC and the NP size...
December 2, 2016: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27913241/evaluation-of-highly-branched-cyclic-dextrin-in-inhalable-particles-of-combined-antibiotics-for-the-pulmonary-delivery-of-anti-tuberculosis-drugs
#2
Kazunori Kadota, Arisa Senda, Hideaki Tagishi, John Oluwasogo Ayorinde, Yuichi Tozuka
This work aims to identify a suitable formulation for the pulmonary delivery of combinations of inhalational drugs using highly branched cyclic dextrin (HBCD) macromolecules. We compared the effectiveness between powders prepared from HBCD with those prepared from five alternative excipients (lactose, maltose, sucrose, β-cyclodextrin and methyl β-cyclodextrin) in the pulmonary delivery of a single-dosage form of two anti-tuberculosis drugs (isoniazid and rifampicin). Fine particles of untreated active pharmaceutical ingredients (APIs) and combination products using excipients were prepared by spray drying...
November 29, 2016: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/27912064/modular-assembly-of-the-bacterial-large-ribosomal-subunit
#3
Joseph H Davis, Yong Zi Tan, Bridget Carragher, Clinton S Potter, Dmitry Lyumkis, James R Williamson
The ribosome is a complex macromolecular machine and serves as an ideal system for understanding biological macromolecular assembly. Direct observation of ribosome assembly in vivo is difficult, as few intermediates have been isolated and thoroughly characterized. Herein, we deploy a genetic system to starve cells of an essential ribosomal protein, which results in the accumulation of assembly intermediates that are competent for maturation. Quantitative mass spectrometry and single-particle cryo-electron microscopy reveal 13 distinct intermediates, which were each resolved to ∼4-5 Å resolution and could be placed in an assembly pathway...
December 1, 2016: Cell
https://www.readbyqxmd.com/read/27898140/ny-subtyp-av-molluscipoxvirus-p%C3%A3-visad-modern-teknik-identifierar-nya-och-ovanliga-patogener-snabbare
#4
Anna-Lena Hammarin, Yvonne Eklund, Maria Karlberg, Morten Bogh, Per Sikora
Molluscum contagiosum is a viral infection of the epidermis characterized by skin-colored papules or nodules frequently with a central depression. Atypical variants may occur, primarily in immunosuppressed individuals. We here report a case of »giant Molluscum contagiosum« in an immunocompetent child. The patient was presented with a fairly smooth nodule of 2 cm in diameter on the ring finger. Molluscipoxvirus-like virus particles were detected by electron microscopy from the nodule, but since the clinical picture was not compatible with MC, next generation sequencing was performed in order to verify the diagnosis...
November 28, 2016: Läkartidningen
https://www.readbyqxmd.com/read/27896559/antiviral-activity-of-hemolymph-of-podalia-against-rubella-virus
#5
N D Carvalho, R Z Mendonça, M I Oliveira, S P Curti, T F Barbosa, P E Silva, N N Taniwaki, M Tonelotto, D N S Giovanni, R H P Moraes, C A Figueiredo
Many active principles produced by animals, plants and microorganisms have been employed in the development of new drugs for the treatment of human diseases. Among animals known to produce pharmacologically active molecules that interfere in human cell physiology. Rubella virus (genus Rubivirus, family Togaviridae) is a single stranded RNA virus of positive genome polarity. Rubella virus infection of susceptible women during the first trimester of pregnancy often results in long-term virus persistence in the fetus causing multiple organ abnormalities...
November 28, 2016: Cytotechnology
https://www.readbyqxmd.com/read/27889528/tailoring-shape-and-size-of-biogenic-silver-nanoparticles-to-enhance-antimicrobial-efficacy-against-mdr-bacteria
#6
Madhuree Kumari, Shipra Pandey, Ved Prakash Giri, Arpita Bhattacharya, Richa Shukla, Aradhana Mishra, C S Nautiyal
Spherical, rectangular, penta, and hexagonal silver nanoparticles of different dimensions were biosynthesized in an eco-friendly manner by biocontrol agent, Trichoderma viride by manipulating physical parameters, pH, temperature, and reaction time. The particles were characterized by UV-vis spectroscopy; Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and Fourier Transform Infra-red Spectroscopy (FTIR). Shape and size dependent antimicrobial activity of nanoparticles against human pathogens was observed...
November 23, 2016: Microbial Pathogenesis
https://www.readbyqxmd.com/read/27886401/not-all-that-glitters-is-gold-electron-microscopy-study-on-uptake-of-gold-nanoparticles-in-daphnia-magna-and-related-artefacts
#7
Louise Helene Søgaard Jensen, Lars Michael Skjolding, Amalie Thit, Sara Nørgaard Sørensen, Carsten Købler, Kristian Mølhave, Anders Baun
Increasing use of engineered nanoparticles has led to extensive research into their potential hazards to the environment and human health. Cellular uptake from the gut is sparsely investigated and microscopy techniques applied for uptake studies can result in misinterpretations. Various microscopy techniques are used to investigate internalization of 10 nm gold nanoparticles in Daphnia magna gut lumen and gut epithelial cells upon 24h exposure and outline potential artefacts, i.e. high contract precipitates from sample preparation related to these techniques...
November 25, 2016: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/27877915/size-control-and-vacuum-ultraviolet-fluorescence-of-nanosized-kmgf3-single-crystals-prepared-using-femtosecond-laser-pulses
#8
Sotaro Muramatsu, Masahiro Yanagihara, Toru Asaka, Shingo Ono, Tomohito Nagami, Kentaro Fukuda, Toshihisa Suyama, Yuui Yokota, Takayuki Yanagida, Akira Yoshikawa
We fabricated nanosized KMgF3 single crystals via a dry pulsed laser ablation process using femtosecond laser pulses. The sizes, shapes, and crystallographic properties of the crystals were evaluated by transmission electron microscopy (TEM). Almost all of the particles were spherical with diameters of less than 100 nm, and they were not highly agglomerated. Selected-area electron diffraction and high-resolution TEM analyses showed that the particles were single crystals. Particle diameter was controlled within a wide range by adjusting the Ar ambient gas pressure...
2016: Science and Technology of Advanced Materials
https://www.readbyqxmd.com/read/27872205/molecular-architecture-of-the-yeast-elongator-complex-reveals-an-unexpected-asymmetric-subunit-arrangement
#9
Dheva T Setiaputra, Derrick Th Cheng, Shan Lu, Jesse M Hansen, Udit Dalwadi, Cindy Hy Lam, Jeffrey L To, Meng-Qiu Dong, Calvin K Yip
Elongator is a ~850 kDa protein complex involved in multiple processes from transcription to tRNA modification. Conserved from yeast to humans, Elongator is assembled from two copies of six unique subunits (Elp1 to Elp6). Despite the wealth of structural data on the individual subunits, the overall architecture and subunit organization of the full Elongator and the molecular mechanisms of how it exerts its multiple activities remain unclear. Using single-particle electron microscopy (EM), we revealed that yeast Elongator adopts a bilobal architecture and an unexpected asymmetric subunit arrangement resulting from the hexameric Elp456 subassembly anchored to one of the two Elp123 lobes that form the structural scaffold...
November 21, 2016: EMBO Reports
https://www.readbyqxmd.com/read/27871963/uptake-of-silica-nanoparticles-in-the-brain-and-effects-on-neuronal-differentiation-using-different-in-vitro-models
#10
A D Ducray, A Stojiljkovic, A Möller, M H Stoffel, H R Widmer, M Frenz, M Mevissen
Nanomedicine offers a promising tool for therapies of brain diseases, but they may be associated with potential adverse effects. The aim of this study was to investigate the uptake of silica-nanoparticles engineered for laser-tissue soldering in the brain using SH-SY5Y cells, dissociated and organotypic slice cultures from rat hippocampus. Nanoparticles were predominantly taken up by microglial cells in the hippocampal cultures but nanoparticles were also found in differentiated SH-SY5Y cells. The uptake was time- and concentration-dependent in primary hippocampal cells...
November 18, 2016: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/27855499/synthesis-and-characterization-of-fe3o4-mptms-plga-nanocomposites-for-anticancer-drug-loading-and-release-studies
#11
Ceren Atila Dinçer, Nuray Yildiz, Ayşe Karakeçili, Nihal Aydoğan, Ayla Çalimli
Magnetic nanocomposites (Fe3O4-MPTMS-PLGA) were synthesized by single oil emulsion method and characterized by transmission electron microscopy (TEM), X-Ray diffraction (XRD), and vibrating sample magnetometer (VSM). Particle size of nanocomposites was between 117 nm and 246 nm. High performance liquid chromatography (HPLC) was used to investigate drug loading (paclitaxel, PTX) and release from Fe3O4-MPTMS-PLGA-PTX nanocomposites. The percentages of drug loading and encapsulation efficiency onto nanocomposites were found as 7...
November 18, 2016: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/27847357/visualization-of-hiv-t-cell-virological-synapses-and-virus-containing-compartments-by-3d-correlative-light-and-electron-microscopy
#12
Lili Wang, Edward T Eng, Kenneth Law, Ronald E Gordon, William J Rice, Benjamin K Chen
: Virological synapses (VS) are adhesive structures that form between infected and uninfected cells that can enhance the spread of HIV-1. During T cell VS formation, viral proteins are actively recruited to the site of cell-cell contact where the viral material is efficiently translocated to target cells into heterogeneous, protease-resistant, antibody-inaccessible compartments. Using correlative light and electron microscopy (CLEM) we define the membrane topography of the virus-containing compartments (VCC) where HIV is found following VS-mediated transfer...
November 9, 2016: Journal of Virology
https://www.readbyqxmd.com/read/27843059/ultrasonic-synthesis-of-two-new-zinc-ii-bipyridine-coordination-polymers-new-precursors-for-preparation-of-zinc-ii-oxide-nano-particles
#13
Mohammad Jaafar Soltanian Fard, Payam Hayati, Azita Firoozadeh, Jan Janczak
Nanoparticles of two zinc(II) coordination polymers (CPs), [Zn(μ-4,4'-bipy)Cl2]n (1) and [Zn(μ-4,4'-bipy)Br2]n (2) L=bpy=4,4'-bipyridine ligand, have been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) spectroscopy and elemental analyses. The single crystal X-ray data of compounds 1 and 2 imply that the Zn(+2) ions are four coordinated. Topological analysis shows that 1D coordination networks of 1 and 2 can be classified as underlying nets of topological types 2C1...
March 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/27830193/human-norovirus-aptamer-exhibits-high-degree-of-target-conformation-dependent-binding-similar-to-that-of-receptors-and-discriminates-particle-functionality
#14
Matthew D Moore, Benjamin G Bobay, Brittany Mertens, Lee-Ann Jaykus
Although two in vitro cultivation methods have been reported, discrimination of infectious human norovirus particles for study of viral inactivation is still a challenge, as both rely on reverse transcriptase quantitative PCR. Histo-blood group antigen (HBGA) binding assays serve as a proxy for estimation of infectious particles; however, they are costly and difficult to purify/modify. Some evidence suggests that certain nucleic acid aptamers only bind intact target proteins, thus displaying a high degree of conformation-dependent binding...
November 2016: MSphere
https://www.readbyqxmd.com/read/27826504/on-the-pathway-of-cellular-uptake-new-insight-into-the-interaction-between-the-cell-membrane-and-very-small-nanoparticles
#15
Claudia Messerschmidt, Daniel Hofmann, Anja Kroeger, Katharina Landfester, Volker Mailänder, Ingo Lieberwirth
For any living cell the exchange with its environment is vital. Therefore, many different kinds of cargo are able to enter cells via energy-dependent or -independent routes. Nanoparticles are no exemption. It is known that small silica nanoparticles with a diameter below 50 nm are taken up by cells and that their uptake exerts pronounced toxic effects beyond a certain concentration threshold. However, neither the exact uptake mechanism of these particles nor the actual reason for their toxicity has yet been elucidated...
2016: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/27824978/fractographic-analysis-of-a-clinically-failed-fpd-after-10-years-in-service
#16
Youssef S Al Jabbari
This study retrieved and analyzed by scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) the failure of a single four-unit fixed partial denture (FPD). Low SEM magnifications revealed a smooth/featureless fracture surface, indicating brittle fracture. Higher magnifications revealed a small fatigue fracture region located on the inferior part of the connector. EDS analysis indicated that the FPD alloy was gold-based. Additionally, SEM showed segregation of small spherical particles at grain boundaries of the alloy, with high aluminum and oxygen content...
November 2016: International Journal of Prosthodontics
https://www.readbyqxmd.com/read/27821763/design-of-a-molecular-support-for-cryo-em-structure-determination
#17
Thomas G Martin, Tanmay A M Bharat, Andreas C Joerger, Xiao-Chen Bai, Florian Praetorius, Alan R Fersht, Hendrik Dietz, Sjors H W Scheres
Despite the recent rapid progress in cryo-electron microscopy (cryo-EM), there still exist ample opportunities for improvement in sample preparation. Macromolecular complexes may disassociate or adopt nonrandom orientations against the extended air-water interface that exists for a short time before the sample is frozen. We designed a hollow support structure using 3D DNA origami to protect complexes from the detrimental effects of cryo-EM sample preparation. For a first proof-of-principle, we concentrated on the transcription factor p53, which binds to specific DNA sequences on double-stranded DNA...
November 22, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27815530/cross-linking-reveals-laminin-coiled-coil-architecture
#18
Gad Armony, Etai Jacob, Toot Moran, Yishai Levin, Tevie Mehlman, Yaakov Levy, Deborah Fass
Laminin, an ∼800-kDa heterotrimeric protein, is a major functional component of the extracellular matrix, contributing to tissue development and maintenance. The unique architecture of laminin is not currently amenable to determination at high resolution, as its flexible and narrow segments complicate both crystallization and single-particle reconstruction by electron microscopy. Therefore, we used cross-linking and MS, evaluated using computational methods, to address key questions regarding laminin quaternary structure...
November 22, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27813287/efficient-decarbonylation-of-furfural-to-furan-catalyzed-by-zirconia-supported-palladium-clusters-with-low-atomicity
#19
Tamao Ishida, Kurumi Kume, Kota Kinjo, Tetsuo Honma, Kengo Nakada, Hironori Ohashi, Takushi Yokoyama, Akiyuki Hamasaki, Haruno Murayama, Yusuke Izawa, Masaru Utsunomiya, Makoto Tokunaga
Decarbonylation of furfural to furan was efficiently catalyzed by ZrO2 -supported Pd clusters in the liquid phase under a N2 atmosphere without additives. Although Pd/C and Pd/Al2 O3 have frequently been used for decarbonylation, Pd/ZrO2 exhibited superior catalytic performance compared with these conventional catalysts. Transmission electron microscopy and X-ray absorption fine structure measurements revealed that the size of the Pd particles decreased with an increase in the specific surface area of ZrO2 ...
November 4, 2016: ChemSusChem
https://www.readbyqxmd.com/read/27807242/evolution-and-cryo-em-capsid-structure-of-a-north-american-bat-adenovirus-and-its-relationship-to-other-mastadenoviruses
#20
Nicole Hackenbrack, Matthew B Rogers, Robert E Ashley, M Kevin Keel, Steven V Kubiski, John A Bryan, Elodie Ghedin, Edward C Holmes, Susan L Hafenstein, Andrew B Allison
: Since the first description of adenoviruses in bats in 2006, a number of micro- and megabat species in Europe, Africa, and Asia have been shown to carry a wide diversity of adenoviruses. Here, we report on the evolutionary, biological, and structural characterization of a novel bat adenovirus (BtAdV 250-A) recovered from a Rafinesque's big-eared bat (Corynorhinus rafinesquii) in Kentucky, USA, which is the first adenovirus isolated from North American bats. BtAdV 250-A exhibits a close phylogenetic relationship with Canine mastadenovirus A (CAdV A), as previously observed with other BtAdVs...
November 2, 2016: Journal of Virology
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