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https://www.readbyqxmd.com/read/28635493/the-structure-of-lamin-filaments-in-somatic-cells-as-revealed-by-cryo-electron-tomography
#1
Y Turgay, O Medalia
Metazoan nuclei are equipped with nuclear lamina - a thin layer of intermediate filaments (IFs) mostly built of nuclear lamins facing the inner nuclear membrane (INM). The nuclear lamina serves as an interaction hub for INM-proteins, soluble nuclear factors and DNA. It confers structural and mechanical stability to the nucleus, transduces mechanical forces and biochemical signals across the nuclear envelope (NE) and regulates the organization of chromatin. By utilizing cryo-electron tomography (cryo-ET), we recently provided an unprecedented view into the 3D organization of lamin filaments within the lamina meshwork in mammalian somatic cells...
June 21, 2017: Nucleus
https://www.readbyqxmd.com/read/28632986/atom-probe-tomography-unveils-formation-mechanisms-of-wear-protective-tribofilms-by-zddp-ionic-liquid-and-their-combination
#2
Wei Guo, Yan Zhou, Xiahan Sang, Donovan N Leonard, Jun Qu, Jonathan D Poplawsky
The development of advanced lubricant additives has been a critical component for in paving the way for increasing energy efficiency and durability for numerous industry applications. However, the formation mechanisms of additive-induced protective tribofilms are not yet fully understood due to the complex chemomechanical interactions at the contact interface and the limited spatial resolution of many characterizing techniques currently used. Here, the tribofilms on a grey cast iron surface formed by three antiwear additives are systematically studied; a phosphonium-phosphate ionic liquid (IL), a zinc dialkyldithiophosphate (ZDDP), and an IL+ZDDP combination...
June 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28630150/cryo-electron-tomography-an-ideal-method-to-study-membrane-associated-proteins
#3
REVIEW
Michelle A Dunstone, Alex de Marco
Cryo-electron tomography (cryo-ET) is a three-dimensional imaging technique that makes it possible to analyse the structure of complex and dynamic biological assemblies in their native conditions. The latest technological and image processing developments demonstrate that it is possible to obtain structural information at nanometre resolution. The sample preparation required for the cryo-ET technique does not require the isolation of a protein and other macromolecular complexes from its native environment. Therefore, cryo-ET is emerging as an important tool to study the structure of membrane-associated proteins including pores...
August 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28628253/3d-atomic-scale-insights-into-anisotropic-core-shell-structured-ingaas-nanowires-grown-by-metal-organic-chemical-vapor-deposition
#4
Jiangtao Qu, Sichao Du, Tim Burgess, Changhong Wang, Xiangyuan Cui, Qiang Gao, Weichao Wang, Hark Hoe Tan, Hui Liu, Chennupati Jagadish, Yingjie Zhang, Hansheng Chen, Mansoor Khan, Simon Ringer, Rongkun Zheng
III-V ternary InGaAs nanowires have great potential for electronic and optoelectronic device applications; however, the 3D structure and chemistry at the atomic-scale inside the nanowires remain unclear, which hinders tailoring the nanowires for specific applications. Here, atom probe tomography is used in conjunction with a first-principles simulation to investigate the 3D structure and chemistry of InGaAs nanowires, and reveals i) the nanowires form a spontaneous core-shell structure with a Ga-enriched core and an In-enriched shell, due to different growth mechanisms in the axial and lateral directions; ii) the shape of the core evolves from hexagon into Reuleaux triangle and grows larger, which results from In outward and Ga inward interdiffusion occurring at the core-shell interface; and iii) the irregular hexagonal shell manifests an anisotropic growth rate on {112}A and {112}B facets...
June 19, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28625752/neurologic-complications-of-extracorporeal-membrane-oxygenation-a-review
#5
REVIEW
Ashleigh Xie, Phillip Lo, Tristan D Yan, Paul Forrest
OBJECTIVE: To review the evidence on neurologic complications in adult extracorporeal membrane oxygenation (ECMO) patients with regard to incidence, pathophysiology, risk factors, diagnosis, monitoring techniques, prevention, and management. DESIGN: Literature review. SETTING: Observational studies and case reports from a variety of institutions. PARTICIPANTS: Adult ECMO patients. INTERVENTIONS: Six electronic databases were searched from their dates of inception to October 2016...
March 2, 2017: Journal of Cardiothoracic and Vascular Anesthesia
https://www.readbyqxmd.com/read/28623631/effect-of-in-vitro-enzymatic-degradation-on-3d-printed-poly-%C3%AE%C2%B5-caprolactone-scaffolds-morphological-chemical-and-mechanical-properties
#6
Joana Ferreira, Antonio Gloria, Stefania Cometa, Jorge F J Coelho, Marco Domingos
BACKGROUND: In recent years, the tissue engineering (TE) field has significantly benefited from advanced techniques such as additive manufacturing (AM), for the design of customized 3D scaffolds with the aim of guided tissue repair. Among the wide range of materials available to biomanufacture 3D scaffolds, poly(ε-caprolactone) (PCL) clearly arises as the synthetic polymer with the greatest potential, due to its unique properties - namely, biocompatibility, biodegradability, thermal and chemical stability and processability...
June 15, 2017: Journal of Applied Biomaterials & Functional Materials
https://www.readbyqxmd.com/read/28623319/fast-projection-matching-for-x-ray-tomography
#7
Chun-Chieh Wang, Cheng-Cheng Chiang, Biqing Liang, Gung-Chian Yin, Yi-Tse Weng, Liang-Chi Wang
X-ray 3D tomographic techniques are powerful tools for investigating the morphology and internal structures of specimens. A common strategy for obtaining 3D tomography is to capture a series of 2D projections from different X-ray illumination angles of specimens mounted on a finely calibrated rotational stage. However, the reconstruction quality of 3D tomography relies on the precision and stability of the rotational stage, i.e. the accurate alignment of the 2D projections in the correct three-dimensional positions...
June 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28623258/chromatin-organization-regulates-viral-egress-dynamics
#8
Vesa Aho, Markko Myllys, Visa Ruokolainen, Satu Hakanen, Elina Mäntylä, Jori Virtanen, Veijo Hukkanen, Thomas Kühn, Jussi Timonen, Keijo Mattila, Carolyn A Larabell, Maija Vihinen-Ranta
Various types of DNA viruses are known to elicit the formation of a large nuclear viral replication compartment and marginalization of the cell chromatin. We used three-dimensional soft x-ray tomography, confocal and electron microscopy, combined with numerical modelling of capsid diffusion to analyse the molecular organization of chromatin in herpes simplex virus 1 infection and its effect on the transport of progeny viral capsids to the nuclear envelope. Our data showed that the formation of the viral replication compartment at late infection resulted in the enrichment of heterochromatin in the nuclear periphery accompanied by the compaction of chromatin...
June 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28621785/three-dimensional-atomic-models-from-a-single-projection-using-z-contrast-imaging-verification-by-electron-tomography-and-opportunities
#9
A De Backer, L Jones, I Lobato, T Altantzis, B Goris, P D Nellist, S Bals, S Van Aert
In order to fully exploit structure-property relations of nanomaterials, three-dimensional (3D) characterization at the atomic scale is often required. In recent years, the resolution of electron tomography has reached the atomic scale. However, such tomography typically requires several projection images demanding substantial electron dose. A newly developed alternative circumvents this by counting the number of atoms across a single projection. These atom counts can be used to create an initial atomic model with which an energy minimization can be applied to obtain a relaxed 3D reconstruction of the nanoparticle...
June 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/28621666/9%C3%A3-structure-of-the-copi-coat-reveals-that-the-arf1-gtpase-occupies-two-contrasting-molecular-environments
#10
Svetlana O Dodonova, Patrick Aderhold, Juergen Kopp, Iva Ganeva, Simone Röhling, Wim J Hagen, Irmgard Sinning, Felix Wieland, John Ag Briggs
COPI coated vesicles mediate trafficking within the Golgi apparatus and between the Golgi and the endoplasmic reticulum. Assembly of a COPI coated vesicle is initiated by the small GTPase Arf1 that recruits the coatomer complex to the membrane, triggering polymerization and budding. The vesicle uncoats before fusion with a target membrane. Coat components are structurally conserved between COPI and clathrin/adaptor proteins. Using cryo-electron tomography and subtomogram averaging, we determined the structure of the COPI coat assembled on membranes in vitro at 9 Å resolution...
June 16, 2017: ELife
https://www.readbyqxmd.com/read/28621616/prevalence-of-foramen-arcuale-and-its-clinical-significance-a-meta-analysis-of-55-985-subjects
#11
Przemysław A Pękala, Brandon M Henry, Jakub R Pękala, Wan Chin Hsieh, Jens Vikse, Beatrice Sanna, Jerzy A Walocha, R Shane Tubbs, Krzysztof A Tomaszewski
OBJECTIVE The foramen arcuale (FA) is a bony bridge located over the vertebral artery on the posterior arch of the atlas. The presence of an FA can pose a risk during neurosurgery by providing a false impression of a broader posterior arch. The aim of this study was to provide the most comprehensive investigation on the prevalence of the FA and its clinically important anatomical features. METHODS Major electronic databases were searched to identify all studies that reported relevant data on the FA and the data were pooled into a meta-analysis...
June 16, 2017: Journal of Neurosurgery. Spine
https://www.readbyqxmd.com/read/28620551/mitochondrial-cardiomyopathy-presenting-as-dilated-phase-of-hypertrophic-cardiomyopathy-diagnosed-with-histological-and-genetic-analyses
#12
Toshiki Kuno, Syohei Imaeda, Yohei Asakawa, Hiroshi Nakamura, Genzou Takemura, Daisuke Asahara, Akira Kanamori, Tomoyuki Kabutoya, Yohei Numasawa
We report a case with 46-year-old man diagnosed with mitochondrial cardiomyopathy in the dilated phase of hypertrophic cardiomyopathy. Since cardiac magnetic resonance imaging, beta-methyl-p-(123)I-iodophenyl-pentadecanoic myocardial scintigraphy, and positron emission tomography/computed tomography revealed no remarkable findings, we performed electron microscopic examination, which aided in diagnosing mitochondrial cardiomyopathy. Muscle biopsy was also compatible with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes and DNA analysis also concluded it...
2017: Case Reports in Cardiology
https://www.readbyqxmd.com/read/28618160/vaccinia-virus-a11-is-required-for-membrane-rupture-and-viral-membrane-assembly
#13
Cristina Suarez, Simone Hoppe, Esthel Pénard, Paul Walther, Jacomine Krijnse Locker
While most enveloped viruses acquire their membrane from the host by budding or a wrapping process, collective data argue that nucleo-cytoplasmic large DNA viruses (NCLDVs) may be an exception. The prototype member of NCLDVs, vaccinia virus (VACV) may induce rupture of ER-derived membranes to build an open membrane sphere that closes after DNA uptake. This unconventional membrane assembly pathway is also used by at least three other members of the NCLDVs. In this study we identify the VACV gene product of A11, as required for membrane rupture, hence for VACV-membrane assembly and virion formation...
June 15, 2017: Cellular Microbiology
https://www.readbyqxmd.com/read/28615944/the-interactions-of-single-wall-carbon-nanohorns-with-polar-epithelium
#14
Yujie Shi, Zujin Shi, Suxin Li, Yuan Zhang, Bing He, Dong Peng, Jie Tian, Ming Zhao, Xueqing Wang, Qiang Zhang
Single-wall carbon nanohorns (SWCNHs), which have multitudes of horn interstices, an extensive surface area, and a spherical aggregate structure, offer many advantages over other carbon nanomaterials being used as a drug nanovector. The previous studies on the interaction between SWCNHs and cells have mostly emphasized on cellular uptake and intracellular trafficking, but seldom on epithelial cells. Polar epithelium as a typical biological barrier constitutes the prime obstacle for the transport of therapeutic agents to target site...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28613838/nanophase-segregation-of-self-assembled-monolayers-on-gold-nanoparticles
#15
Santosh Kumar Meena, Claire Goldmann, Douga Nassoko, Mahamadou Seydou, Thomas Marchandier, Simona Moldovan, Ovidiu Ersen, François Ribot, Corinne Chanéac, Clément Sanchez, David Portehault, Frederik Tielens, Marialore Sulpizi
Nanophase segregation of a bicomponent thiol self-assembled monolayer is predicted using atomistic molecular dynamics simulations and experimentally confirmed. The simulations suggest the formation of domains rich in acid-terminated chains, on one hand, and of domains rich in amide-functionalized ethylene glycol oligomers, on the other hand. In particular, within the amide-ethylene glycol oligomers region, a key role is played by the formation of interchain hydrogen bonds. The predicted phase segregation is experimentally confirmed by the synthesis of 35 and 15 nm gold nanoparticles functionalized with several binary mixtures of ligands...
June 21, 2017: ACS Nano
https://www.readbyqxmd.com/read/28611809/proteomic-analysis-of-lipid-droplets-from-arabidopsis-aging-leaves-brings-new-insight-into-their-biogenesis-and-functions
#16
Lysiane Brocard, Françoise Immel, Denis Coulon, Nicolas Esnay, Karine Tuphile, Stéphanie Pascal, Stéphane Claverol, Laëtitia Fouillen, Jean-Jacques Bessoule, Claire Bréhélin
Lipid droplets (LDs) are cell compartments specialized for oil storage. Although their role and biogenesis are relatively well documented in seeds, little is known about their composition, structure and function in senescing leaves where they also accumulate. Here, we used a label free quantitative mass spectrometry approach to define the LD proteome of aging Arabidopsis leaves. We found that its composition is highly different from that of seed/cotyledon and identified 28 proteins including 9 enzymes of the secondary metabolism pathways involved in plant defense response...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28611678/a-fourth-klk4-mutation-is-associated-with-enamel-hypomineralisation-and-structural-abnormalities
#17
Claire E L Smith, Jennifer Kirkham, Peter F Day, Francesca Soldani, Esther J McDerra, James A Poulter, Christopher F Inglehearn, Alan J Mighell, Steven J Brookes
"Amelogenesis imperfecta" (AI) describes a group of genetic conditions that result in defects in tooth enamel formation. Mutations in many genes are known to cause AI, including the gene encoding the serine protease, kallikrein related peptidase 4 (KLK4), expressed during the maturation stage of amelogenesis. In this study we report the fourth KLK4 mutation to be identified in autosomal recessively-inherited hypomaturation type AI, c.632delT, p.(L211Rfs(*)37) (NM_004917.4, NP_004908.4). This homozygous variant was identified in five Pakistani AI families and is predicted to result in a transcript with a premature stop codon that escapes nonsense mediated decay...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28611252/the-primary-enveloped-virion-of-herpes-simplex-virus-1-its-role-in-nuclear-egress
#18
William W Newcomb, Juan Fontana, Dennis C Winkler, Naiqian Cheng, J Bernard Heymann, Alasdair C Steven
Many viruses migrate between different cellular compartments for successive stages of assembly. The HSV-1 capsid assembles in the nucleus and then transfers into the cytoplasm. First, the capsid buds through the inner nuclear membrane, becoming coated with nuclear egress complex (NEC) protein. This yields a primary enveloped virion (PEV) whose envelope fuses with the outer nuclear membrane, releasing the capsid into the cytoplasm. We investigated the associated molecular mechanisms by isolating PEVs from US3-null-infected cells and imaging them by cryo-electron microscopy and tomography...
June 13, 2017: MBio
https://www.readbyqxmd.com/read/28611005/bottom-up-synthesis-of-ws2-nanosheets-with-synchronous-surface-modification-for-imaging-guided-tumor-regression
#19
Shige Wang, Jiulong Zhao, Hailun Yang, Chenyao Wu, Fei Hu, Haizhou Chang, Guixiang Li, Dan Ma, Duowu Zou, Mingxian Huang
Two-dimensional transition metal dichalcogenides (TMDs) have been receiving great attention as NIR photothermal transducing agent in tumor photothermal therapy. Keeping in mind the low efficiency of the conventional top-down exfoliation method to produce 2D TMDs and the complexity of their surface modifications, we herein proposed a bottom-up strategy for the one-pot and controlled synthesis of surface polyvinyl pyrrolidone (PVP) modified WS2 nanosheets, by hydrothermally treating the mixture solution of tetrathiotungstate and PVP...
June 10, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28609782/influence-of-dna-sequence-on-the-structure-of-minicircles-under-torsional-stress
#20
Qian Wang, Rossitza N Irobalieva, Wah Chiu, Michael F Schmid, Jonathan M Fogg, Lynn Zechiedrich, B Montgomery Pettitt
The sequence dependence of the conformational distribution of DNA under various levels of torsional stress is an important unsolved problem. Combining theory and coarse-grained simulations shows that the DNA sequence and a structural correlation due to topology constraints of a circle are the main factors that dictate the 3D structure of a 336 bp DNA minicircle under torsional stress. We found that DNA minicircle topoisomers can have multiple bend locations under high torsional stress and that the positions of these sharp bends are determined by the sequence, and by a positive mechanical correlation along the sequence...
June 13, 2017: Nucleic Acids Research
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