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cryo electron tomography

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https://www.readbyqxmd.com/read/28925789/motile-cilia-defects-in-diseases-other-than-primary-ciliary-dyskinesia-the-contemporary-diagnostic-and-research-role-for-transmission-electron-microscopy
#1
Hannah M Mitchison, Amelia Shoemark
Ultrastructural studies have underpinned the cell biological and clinical investigations of the varied roles of motile cilia in health and disease, with a long history since the 1950s. Recent developments from transmission electron microscopy (TEM; cryo-electron microscopy, electron tomography) have yielded higher resolution and fresh insights into the structure and function of these complex organelles. Microscopy in ciliated organisms, disease models, and in patients with ciliopathy diseases has dramatically expanded our understanding of the ubiquity, multisystem involvement, and importance of cilia in normal human development...
September 19, 2017: Ultrastructural Pathology
https://www.readbyqxmd.com/read/28915442/electron-cryo-tomography-captures-macromolecular-complexes-in-native-environments
#2
REVIEW
Lindsay A Baker, Michael Grange, Kay Grünewald
Transmission electron microscopy has a long history in cellular biology. Fixed and stained samples have been used for cellular imaging for over 50 years, but suffer from sample preparation induced artifacts. Electron cryo-tomography (cryoET) instead uses frozen-hydrated samples, without chemical modification, to determine the structure of macromolecular complexes in their native environment. Recent developments in electron microscopes and associated technologies have greatly expanded our ability to visualize cellular features and determine the structures of macromolecular complexes in situ...
September 12, 2017: Current Opinion in Structural Biology
https://www.readbyqxmd.com/read/28890085/in-situ-architecture-and-cellular-interactions-of-polyq-inclusions
#3
Felix J B Bäuerlein, Itika Saha, Archana Mishra, Maria Kalemanov, Antonio Martínez-Sánchez, Rüdiger Klein, Irina Dudanova, Mark S Hipp, F Ulrich Hartl, Wolfgang Baumeister, Rubén Fernández-Busnadiego
Expression of many disease-related aggregation-prone proteins results in cytotoxicity and the formation of large intracellular inclusion bodies. To gain insight into the role of inclusions in pathology and the in situ structure of protein aggregates inside cells, we employ advanced cryo-electron tomography methods to analyze the structure of inclusions formed by polyglutamine (polyQ)-expanded huntingtin exon 1 within their intact cellular context. In primary mouse neurons and immortalized human cells, polyQ inclusions consist of amyloid-like fibrils that interact with cellular endomembranes, particularly of the endoplasmic reticulum (ER)...
August 29, 2017: Cell
https://www.readbyqxmd.com/read/28883390/prophage-triggered-membrane-vesicle-formation-through-peptidoglycan-damage-in-bacillus-subtilis
#4
Masanori Toyofuku, Gerardo Cárcamo-Oyarce, Tatsuya Yamamoto, Fabian Eisenstein, Chien-Chi Hsiao, Masaharu Kurosawa, Karl Gademann, Martin Pilhofer, Nobuhiko Nomura, Leo Eberl
Bacteria release membrane vesicles (MVs) that play important roles in various biological processes. However, the mechanisms of MV formation in Gram-positive bacteria are unclear, as these cells possess a single cytoplasmic membrane that is surrounded by a thick cell wall. Here we use live cell imaging and electron cryo-tomography to describe a mechanism for MV formation in Bacillus subtilis. We show that the expression of a prophage-encoded endolysin in a sub-population of cells generates holes in the peptidoglycan cell wall...
September 7, 2017: Nature Communications
https://www.readbyqxmd.com/read/28881141/elongated-plant-virus-based-nanoparticles-for-enhanced-delivery-of-thrombolytic-therapies
#5
Andrzej Stanislaw Pitek, Yunmei Wang, Sahil Gulati, Huiyun Gao, Phoebe L Stewart, Daniel I Simon, Nicole F Steinmetz
Thrombotic cardiovascular disease, including acute myocardial infarction, ischemic stroke, and venous thromboembolic disease, is the leading cause of morbidity and mortality worldwide. While reperfusion therapy with thrombolytic agents reduces mortality from acute myocardial infarction and disability from stroke, thrombolysis is generally less effective than mechanical reperfusion and is associated with fatal intra-cerebral hemorrhage in up to 2-4% of patients. To address these limitations, we propose the tobacco mosaic virus (TMV)-based platform technology for targeted delivery of thrombolytic therapies...
September 7, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28872144/volume-segmentation-and-analysis-of-biological-materials-using-survos-super-region-volume-segmentation-workbench
#6
Michele C Darrow, Imanol Luengo, Mark Basham, Matthew C Spink, Sarah Irvine, Andrew P French, Alun W Ashton, Elizabeth M H Duke
Segmentation is the process of isolating specific regions or objects within an imaged volume, so that further study can be undertaken on these areas of interest. When considering the analysis of complex biological systems, the segmentation of three-dimensional image data is a time consuming and labor intensive step. With the increased availability of many imaging modalities and with automated data collection schemes, this poses an increased challenge for the modern experimental biologist to move from data to knowledge...
August 23, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28861820/semiautomatic-segmentation-of-plant-golgi-stacks-in-electron-tomograms-using-3dmod
#7
Keith Ka Ki Mai, Byung-Ho Kang
Electron tomography is a powerful tool for visualizing subcellular organelles. With the advances in cryo-fixation techniques, it is now possible to reconstruct complex structures in cells preserved close to their native states in three-dimension (3D) using electron tomography. In order to better visualize these objects, 3D models are made from outlines of organelles in individual tomographic slices, which can be used to display morphological features and quantify structural parameters. While outlines of simple organelles can be drawn by hand fairly quickly, it is possible to accelerate 3D modeling of more complex organelles by means of semiautomatic segmentation...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28830949/the-fusion-loops-of-the-initial-prefusion-conformation-of-herpes-simplex-virus-1-fusion-protein-point-toward-the-membrane
#8
Juan Fontana, Doina Atanasiu, Wan Ting Saw, John R Gallagher, Reagan G Cox, J Charles Whitbeck, Lauren M Brown, Roselyn J Eisenberg, Gary H Cohen
All enveloped viruses, including herpesviruses, must fuse their envelope with the host membrane to deliver their genomes into target cells, making this essential step subject to interference by antibodies and drugs. Viral fusion is mediated by a viral surface protein that transits from an initial prefusion conformation to a final postfusion conformation. Strikingly, the prefusion conformation of the herpesvirus fusion protein, gB, is poorly understood. Herpes simplex virus (HSV), a model system for herpesviruses, causes diseases ranging from mild skin lesions to serious encephalitis and neonatal infections...
August 22, 2017: MBio
https://www.readbyqxmd.com/read/28827470/visualization-of-cytosolic-ribosomes-on-the-surface-of-mitochondria-by-electron-cryo-tomography
#9
Vicki Am Gold, Piotr Chroscicki, Piotr Bragoszewski, Agnieszka Chacinska
We employed electron cryo-tomography to visualize cytosolic ribosomes on the surface of mitochondria. Translation-arrested ribosomes reveal the clustered organization of the TOM complex, corroborating earlier reports of localized translation. Ribosomes are shown to interact specifically with the TOM complex, and nascent chain binding is crucial for ribosome recruitment and stabilization. Ribosomes are bound to the membrane in discrete clusters, often in the vicinity of the crista junctions. This interaction highlights how protein synthesis may be coupled with transport...
August 21, 2017: EMBO Reports
https://www.readbyqxmd.com/read/28811642/octahedron-iron-oxide-nanocrystals-prohibited-clostridium-difficile-spore-germination-and-attenuated-local-and-systemic-inflammation
#10
Wei-Ting Lee, Ya-Na Wu, Yi-Hsuan Chen, Shang-Rung Wu, Tsai-Miao Shih, Tsung-Ju Li, Li-Xing Yang, Chen-Sheng Yeh, Pei-Jane Tsai, Dar-Bin Shieh
Clinical management of Clostridium difficile infection is still far from satisfactory as bacterial spores are resistant to many chemical agents and physical treatments. Certain types of nanoparticles have been demonstrated to exhibit anti-microbial efficacy even in multi-drug resistance bacteria. However, most of these studies failed to show biocompatibility to the mammalian host cells and no study has revealed in vivo efficacy in C. difficile infection animal models. The spores treated with 500 µg/mL Fe3-δO4 nanoparticles for 20 minutes, 64% of the spores were inhibited from transforming into vegetative cells, which was close to the results of the sodium hypochlorite-treated positive control...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28810122/crystal-face-distributions-and-surface-site-densities-of-two-synthetic-goethites-implications-for-adsorption-capacities-as-a-function-of-particle-size
#11
Kenneth J T Livi, Mario Villalobos, Rowan Leary, Maria Varela, Jon Barnard, Milton Villacís-García, Rodolfo Zanella, Anna Goodridge, Paul Midgley
Two synthetic goethites of varying crystal size distributions were analyzed by BET, conventional TEM, cryo-TEM, atomic resolution STEM and HRTEM, and electron tomography in order to determine the effects of crystal size, shape, and atomic scale surface roughness on their adsorption capacities. The two samples were determined by BET to have very different site densities based on Cr(VI) adsorption experiments. Model specific surface areas generated from TEM observations showed that, based on size and shape, there should be little difference in their adsorption capacities...
August 30, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28794042/palmitoylation-contributes-to-membrane-curvature-in-influenza-a-virus-assembly-and-hemagglutinin-mediated-membrane-fusion
#12
Petr Chlanda, Elena Mekhedov, Hang Waters, Alexander Sodt, Cindi Schwartz, Vinod Nair, Paul S Blank, Joshua Zimmerberg
The highly conserved cytoplasmic tail of influenza virus glycoprotein hemagglutinin (HA) contains three cysteines, post-translationally modified by covalently bound fatty acids. While viral HA acylation is crucial in virus replication, its physico-chemical role is unknown. We used virus-like particles (VLP) to study the effect of acylation on morphology, protein incorporation, lipid composition, and membrane fusion. De-acylation interrupted HA-M1 interactions since de-acylated mutant HA fail to incorporate an M1 layer within spheroidal VLP, and filamentous particles incorporated increased numbers of neuraminidase (NA)...
August 9, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28781998/the-advent-of-structural-biology-in-situ-by-single-particle-cryo-electron-tomography
#13
Jesús G Galaz-Montoya, Steven J Ludtke
Single particle tomography (SPT), also known as subtomogram averaging, is a powerful technique uniquely poised to address questions in structural biology that are not amenable to more traditional approaches like X-ray crystallography, nuclear magnetic resonance, and conventional cryoEM single particle analysis. Owing to its potential for in situ structural biology at subnanometer resolution, SPT has been gaining enormous momentum in the last five years and is becoming a prominent, widely used technique. This method can be applied to unambiguously determine the structures of macromolecular complexes that exhibit compositional and conformational heterogeneity, both in vitro and in situ...
2017: Biophysics Reports
https://www.readbyqxmd.com/read/28768871/isolation-and-characterization-of-metallosphaera-turreted-icosahedral-virus-mtiv-a-founding-member-of-a-new-family-of-archaeal-viruses
#14
Cassia Wagner, Vijay Reddy, Francisco Asturias, Maryam Khoshouei, John E Johnson, Pilar Manrique, Jacob Munson-McGee, Wolfgang Baumeister, C Martin Lawrence, Mark J Young
Our understanding of archaeal virus diversity and structure is just beginning to emerge. Here we describe a new archaeal virus, tentatively named Metallosphaera turreted icosahedral virus (MTIV), that was isolated from an acidic hot spring in Yellowstone National Park, USA. Two strains of the virus were identified and found to replicate in an archaeal host species closely related to Metallosphaera yellowstonensis Each strain encodes for a 9.8-9.9 kb, linear dsDNA genome with large inverted terminal repeats...
August 2, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28756276/cryo-electron-microscopy-for-structural-analysis-of-dynamic-biological-macromolecules
#15
REVIEW
Kazuyoshi Murata, Matthias Wolf
BACKGROUND: Since the introduction of what became today's standard for cryo-embedding of biological macromolecules at native conditions more than 30years ago, techniques and equipment have been drastically improved and the structure of biomolecules can now be studied at near atomic resolution by cryo-electron microscopy (cryo-EM) while capturing multiple dynamic states. Here we review the recent progress in cryo-EM for structural studies of dynamic biological macromolecules. SCOPE OF REVIEW: We provide an overview of the cryo-EM method and introduce contemporary studies to investigate biomolecular structure and dynamics, including examples from the recent literature...
July 27, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28743638/efficient-3d-ctf-correction-for-cryo-electron-tomography-using-novactf-improves-subtomogram-averaging-resolution-to-3-4%C3%A3
#16
Beata Turoňová, Florian K M Schur, William Wan, John A G Briggs
Cryo-electron tomography (cryo-ET) allows cellular ultrastructures and macromolecular complexes to be imaged in three-dimensions in their native environments. Cryo-electron tomograms are reconstructed from projection images taken at defined tilt-angles. In order to recover high-resolution information from cryo-electron tomograms, it is necessary to measure and correct for the contrast transfer function (CTF) of the microscope. Most commonly, this is performed using protocols that approximate the sample as a two-dimensional (2D) plane...
July 22, 2017: Journal of Structural Biology
https://www.readbyqxmd.com/read/28735108/structural-biology-outside-the-box-inside-the-cell
#17
REVIEW
Jürgen M Plitzko, Benjamin Schuler, Philipp Selenko
Recent developments in cellular cryo-electron tomography, in-cell single-molecule Förster resonance energy transfer-spectroscopy, nuclear magnetic resonance-spectroscopy and electron paramagnetic resonance-spectroscopy delivered unprecedented insights into the inner workings of cells. Here, we review complementary aspects of these methods and provide an outlook toward joint applications in the future.
July 20, 2017: Current Opinion in Structural Biology
https://www.readbyqxmd.com/read/28733815/structure-of-isolated-z-disks-from-honeybee-flight-muscle
#18
Mara Rusu, Zhongjun Hu, Kenneth A Taylor, John Trinick
The Z-disk is a complex structure comprising some 40 proteins that are involved in the transmission of force developed during muscle contraction and in important signalling pathways that govern muscle homeostasis. In the Z-disk the ends of antiparallel thin filaments from adjacent sarcomeres are crosslinked by α-actinin. The structure of the Z-disk lattice varies greatly throughout the animal kingdom. In vertebrates the thin filaments form a tetragonal lattice, whereas invertebrate flight muscle has a hexagonal lattice...
July 21, 2017: Journal of Muscle Research and Cell Motility
https://www.readbyqxmd.com/read/28726246/cryo-electron-tomography-the-cell-biology-that-came-in-from-the-cold
#19
REVIEW
Jonathan Wagner, Miroslava Schaffer, Rubén Fernández-Busnadiego
Cryo-electron tomography (cryo-ET) provides high-resolution 3D views into cells pristinely preserved by vitrification. Recent technical advances such as direct electron detectors, the Volta phase plate and cryo-focused ion beam milling have dramatically pushed image quality and expanded the range of cryo-ET applications. Cryo-ET not only allows mapping the positions and interactions of macromolecules within their intact cellular context, but can also reveal their in situ structure at increasing resolution...
July 20, 2017: FEBS Letters
https://www.readbyqxmd.com/read/28699890/changes-of-mitochondrial-ultrastructure-and-function-during-ageing-in-mice-and-drosophila
#20
Tobias Brandt, Arnaud Mourier, Luke S Tain, Linda Partridge, Nils-Göran Larsson, Werner Kühlbrandt
Ageing is a progressive decline of intrinsic physiological functions. We examined the impact of ageing on the ultrastructure and function of mitochondria in mouse and fruit flies (Drosophila melanogaster) by electron cryo-tomography and respirometry. We discovered distinct age-related changes in both model organisms. Mitochondrial function and ultrastructure are maintained in mouse heart, whereas subpopulations of mitochondria from mouse liver show age-related changes in membrane morphology. Subpopulations of mitochondria from young and old mouse kidney resemble those described for apoptosis...
July 12, 2017: ELife
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