Microtubules (MTs) exhibit dynamic instability, alternating between phases of growth and shortening, mostly at their uncapped plus ends. Based on results from cryo-electron microscopy it was proposed that growing MTs display mainly curved sheets and blunt ends; during depolymerisation curled ramshorns predominate. Observations of MTs in mitotic cells have suggested that the situation in vivo differs from that in vitro, but so far, a clear comparison between in vivo and in vitro results has not been possible because MT end structures could not be correlated directly with the dynamic state of that particular MT. Here we combine light microscopy and electron tomography (ET) to show that growing MT plus ends in the fission yeast Schizosaccharomyces pombe display predominantly a flared morphology. This indicates that MT polymerisation in vivo and in vitro can follow different paths.. ...
Cryo-electron tomography (Cryo-ET) has emerged as an effective tool for in-situ structural biology because it enables the imaging of macromolecular complexes in their native cellular environments at close to living conditions and at nanometer scale resolution [1-7]. In principle Cryo-ET can be used for studying the structure, abundance and spatial distribution of large macromolecular complexes in various cellular environments [8]. However, the simultaneous identification of all detectable macromolecular complexes in whole cell cryo-electron tomograms (i.e., visual proteomics) remains a considerable challenge. A visual proteomics approach would include the extraction of all potential complexes into individual subtomograms (i.e., particle picking) combined with large-scale reference-free subtomogram classification and subsequent averaging of subtomograms in the same class to generate density maps at increased resolution and signal to noise level [9-13]. However, extracting structural information ...
In principle, this flared appearance could reflect two structures: one where the protofilaments form a single curved sheet structure (Fig. 3A) and another where the individual protofilaments form a funnel with little or loose lateral interaction (Fig. 3B). However, a sheet only appears flared if viewed perpendicular, or close to perpendicular, to the sheet surface; a funnel flares out at any viewing angle. Because we viewed MT ends from all available angles and still observed mostly flared ends (Fig. 3C), we can conclude that in the fission yeast cells, MT plus ends appear to grow by the closing of a funnel-like structure.. Similar flared MT plus-ends were documented in two recent publications, although the dynamic state of those MT ends was not always clear (Koning et al., 2008) or they were visualised during depolymerisation (McIntosh et al., 2008). Flared MT end structures in vivo differ considerably from the curved sheet or blunt end structures that dominate in vitro and in Xenopus egg ...
Bunyaviridae is a large family of viruses that have gained attention as "emerging viruses" because many members cause serious disease in humans, with an increasing number of outbreaks. These negative-strand RNA viruses possess a membrane envelope covered by glycoproteins. The virions are pleiomorphic and thus have not been amenable to structural characterization using common techniques that involve averaging of electron microscopic images. Here, we determined the three-dimensional structure of a member of the Bunyaviridae family by using electron cryotomography. The genome, incorporated as a complex with the nucleoprotein inside the virions, was seen as a thread-like structure partially interacting with the viral membrane. Although no ordered nucleocapsid was observed, lateral interactions between the two membrane glycoproteins determine the structure of the viral particles. In the most regular particles, the glycoprotein protrusions, or "spikes," were seen to be arranged on an icosahedral ...
Cryo-electron tomography (cryo-ET) allows the visualization of cellular structures under close-to-life conditions and at molecular resolution. While it is inherently a static approach, yielding struct
Gag, the major structural component of the type 1 human immunodeficiency virus (HIV-1), comprises the matrix (MA), capsid (CA), nucleocapsid (NC), and p6 proteins, as well as the SP1 and SP2 spacer peptides. In the immature HIV-1 virion, the domains of Gag are arranged radially with the amino-terminus of MA at the membrane. Mature viral particles are formed when Gag is proteolytically cleaved, allowing CA to reassemble into the viral core, which contains NC bound to genomic RNA. While the structures of nearly every HIV-1 protein are known in atomic detail from X-ray crystallography and NMR spectroscopy, many questions remain about the intermolecular interactions in both the immature and mature particles. We have obtained three-dimensional structures of individual immature and mature HIV-1 virus-like particles by cryoelectron tomography. Reconstructions of the mature particles revealed diverse core morphologies with a preference for conical shapes consistent with 5,7 fullerene cones. Uniform ...
I am professor in electron cryotomography and bacterial chemotaxis. I am interested in understanding how microbes sense and respond to their environment. In order to gain insight into the structure and function of the molecular complexes involved in these behaviors, my lab uses electron cryotomography (ECT). This technique allows us to directly study microbes in their native state at resolutions capable of visualizing individual proteins.
In this work a protocol for bright-field electron tomography in the transmission electron microscope (TEM) is developed. This protocol provides high resolution in 3D better than 1nm. It enables to study materials prone to radiolysis effects such as carbon materials. For the latter an aberration corrected TEM operated at a low acceleration voltage of 80kV is necessary to reduce the knock-on related beam damage. This protocol is exemplified on commercially available Vulcan XC-72 carbon soot particles which serve as a support for catalytically active nanoparticles (here platinum). This approach enables to visualize and quantify the internal three-dimensional graphitic nanostructure with ~0.35nm graphitic interplanar distance by layer distance, fringe length and tortuosity providing statistical measures for the 3D carbon volume. The protocol ensures that the sample withstands the entire tilt series acquisition by a minimum dose protocol. The appropriate imaging conditions are specified and ...
Co-translational folding and maturation of proteins require an intricate network of folding chaperones and processing enzymes that act on the growing nascent protein in a co-translational manner. Structural information on ribosome-nascent chain-chaperone complexes is sparse, because the involved interactions are mostly transient, labile and possibly highly flexible. This renders the involved assemblies inaccessible to classical reductionist structural biology approaches that rely on extensive biochemical purification and require conformationally homogenous particle populations for averaging. We consequently pursue a different approach and image these processes using cryo electron tomography (cryo-ET)-based strategies, which can reveal the three-dimensional arrangement of individual macromolecules even in crowded native microenvironments at molecular resolution and therefore render extensive biochemical purification unnecessary. This approach allows us to analyze the three-dimensional spatial ...
Co-translational folding and maturation of proteins require an intricate network of folding chaperones and processing enzymes that act on the growing nascent protein in a co-translational manner. Structural information on ribosome-nascent chain-chaperone complexes is sparse, because the involved interactions are mostly transient, labile and possibly highly flexible. This renders the involved assemblies inaccessible to classical reductionist structural biology approaches that rely on extensive biochemical purification and require conformationally homogenous particle populations for averaging. We consequently pursue a different approach and image these processes using cryo electron tomography (cryo-ET)-based strategies, which can reveal the three-dimensional arrangement of individual macromolecules even in crowded native microenvironments at molecular resolution and therefore render extensive biochemical purification unnecessary. This approach allows us to analyze the three-dimensional spatial ...
For example, the researchers now know that most of the fibers are usually bound to the virus head rather than extended, as was previously thought. That those fibers are in a dynamic equilibrium between bound and extended states is also new. Molineux said that the idea that phages "walk" over the cell surface was previously proposed, but their paper provides the first experimental evidence that this is the case. This is also the first time that scientists have made actual images showing how the viruss tail extends into the host - the very action that allows it to infect a cell with its DNA.. "I first hypothesized that T7 made an extended tail more than 10 years ago," said Molineux, "but this is the first irrefutable experimental evidence for the idea and provides the first images of what it looks like.". The researchers used a combination of genetics and cryo-electron tomography to image the infection process. Cryo-electron tomography is a process similar to a CT scan, but it is scaled to study ...
The issue of protein dynamics and its implications in the biological function of proteins are arousing greater and greater interest in different fields of molecular biology. In cryo-electron tomography experiments one may take several snapshots of a given biological macromolecule. In principle, a large enough collection of snapshots of the molecule may then be used to calculate its equilibrium configuration in terms of the experimentally accessible degrees of freedom and, hence, to estimate its potential energy. This information would be crucial in order to analyze the biological functions of biomolecules by directly accessing the relevant dynamical indicators. In this article, we analyze the results of cryo-electron tomography experiments performed on monoclonal murine IgG2a antibodies. We measure the equilibrium distribution of the molecule in terms of the relevant angular coordinates and build a mechanical model of the antibody dynamics. This approach enables us to derive an explicit ...
ALA is a plant-derived n-3 FA readily available in certain plant oils such as flaxseed, soybean and canola oil. Epidemiological studies have shown an inverse correlation between dietary ALA and cardiovascular events,11,30,31 although the molecular mechanisms of this protection are not completely known. Our group has investigated the molecular basis of several cardio-protective effects of ALA, showing that at least some of its effects are mediated by its action on endothelial cells, leukocytes and platelets.9,10,19 In this study, we have focused in particular on platelet adhesion to vWF under high-shear conditions, which represents the first step mediating platelet activation under arterial flow and is especially important in stenosed (atherosclerotic) arteries, where shear can reach extremely high values (,5,000 s−1).7,32,33. Here we show for the first time that ALA is able to partially inhibit platelet adhesion to vWF under a shear flow of 10,000 s−1, when whole blood is pre-incubated for 1 ...
Application: To obtain a 3D model for objects that are too thick for single particle electron microscopy (≥ 1 micrometer thick), e.g., small cells, cellular organelles, macromolecules and their complexes, viruses. Method: Samples are vitrified by plunge freezing or by high-pressure freezing, cut into thin slices if necessary, and imaged at various tilt angles in the microscope using the lowest possible electron dose. Imaging under low dose conditions minimizes physical damage of the sample during data acquisition, but leads to extremely low signal-to-noise conditions. Sub-tomogram averaging recovers the signal by an intensive computational procedure, yielding structural resolutions of up to ~1 nm.. ...
Transmission electron microscopy (TEM) gives a good image for ultra-intracellular organelles in two-dimensional projections, but to get a three-dimensional structural information, we should use the high-voltage transmission electron tomography (TET). The use of TET is important to resolve the questions about the relation between the different cell organelles and their mechanisms of action to correlate structure to function for medical treatment solutions.
New insights into cellular organisation and cell division of Trypanosoma brucei using cellular electron tomography and serial block face SEM ...
Ilke Arlsan at Pacific Northwest National Laboratory co-wrote an invited review article on electron tomography for Nature Materials.
Pack CG, Yukii H, Toh-e A, Kudo T, Tsuchiya H, Kaiho A, Sakata E, Murata S, Yokosawa H, Sako Y, Baumeister W, Tanaka K, Saeki Y, Quantitative live-cell imaging reveals spatio-temporal dynamics and cytoplasmic assembly of the 26S proteasome. Nat Commun. 5:3396 (2014). Bohn S, Sakata E, Beck F, Pathare GR, Schnitger J, Nágy I, Baumeister W, Förster F. Localization of the regulatory particle subunit Sem1 in the 26S proteasome. Biochem Biophys Res Commun. 435(2):250-354 (2013). Fernández-Busnadiego R, Asano S, Oprisoreanu AM, Sakata E, Doengi M, Kochovski Z, Zürner M, Stein V, Schoch S, Baumeister W, Lucić V. Cryo-electron tomography reveals a critical role of RIM1a in synaptic vesicle tethering. J Cell Biol. 201(5):725-740, (2013). Sugiyama M, Sahashi H, Kurimoto E, Takata S, Yagi H, Kanai K, Sakata E, Minami Y, Tanaka K, Kato K. Spatial arrangement and functional role of α subunits of proteasome activator PA28 in hetero-oligomeric form. Biochem Biophys Res Commun. 432(1):141-145, ...
The Model 2040 Dual-Axis Tomography Holder is for TEM imaging or analysis that requires in situ specimen rotation. Acquiring a dual-axis tilt series enhances the information contained in the tomogram.. The Dual-Axis Tomography Holder features an optimal tilt angle range in narrow gap (~5mm) pole piece geometries, while maintaining microscope resolution.. A fully jeweled mechanism provides ultra-precise, in-plane specimen rotation, while maintaining eucentricity.. The FlexiClamp is a spring-type, annular ring which securely clamps the specimen into the specimen cup. It maximizes specimen visibility, even at high tilt angles. A dedicated tool facilitates the use of the FlexiClamp.. Initially, the specimen can be fully rotated through 360º to orient either the grid bars or a specimen feature to the alpha tilt axis. Once the specimen is properly oriented, the first tilt series is acquired. A two-position precision indexing mechanism provides 90º in-plane rotation. These features greatly facilitate ...
All cells share a universal, minimal set of biochemical processes, essential to all life. The search for defining this minimal set has lead to the synthetic assembly of the first minimal cell, JCVI-syn3.0: a cell with only 473 genes, the bare minimum requirements for independent cellular life. Its genetic basis was Mycoplasma mycoides; the Mycoplasmas have long been of interest to investigate fundamentals of life due to their evolutionarily reduced genomes, and at the same time represent an important class of pathogens, implicated in diseases such as pneumonia, urogenital diseases and certain types of cancer. Thus, JCVI-syn3.0 constitutes a platform to study the function of every gene that is essential for cellular life, and provides simultaneously a prototype for investigating cellular networks in a number of pathogens. The small (sub-micrometer) size and simple genome of JCVI-syn3.0, together with the timely availability of proteomics and cryo-electron tomography (cryo-ET) data in progress, ...
Video articles in JoVE about coated vesicles include Measuring Synaptic Vesicle Endocytosis in Cultured Hippocampal Neurons, Nitrogen Cavitation and Differential Centrifugation Allows for Monitoring the Distribution of Peripheral Membrane Proteins in Cultured Cells, Test Samples for Optimizing STORM Super-Resolution Microscopy, Visualizing Clathrin-mediated Endocytosis of G Protein-coupled Receptors at Single-event Resolution via TIRF Microscopy, Averaging of Viral Envelope Glycoprotein Spikes from Electron Cryotomography Reconstructions using Jsubtomo, Assessing the Secretory Capacity of Pancreatic Acinar Cells, Synthesis of Cationized Magnetoferritin for Ultra-fast Magnetization of Cells, In vivo and in vitro Studies of Adaptor-clathrin Interaction, Preparation of Mouse Brain Tissue for Immunoelectron Microscopy.
Tomography-Guided 3D Reconstruction of Subcellular Structures (TYGRESS) is a hybrid method, which combines the advantageous features of both cryo-electron tomography and single particle cryo-EM to achieve higher resolution than before of complex subcellular structures within their native environment.
develop interdisciplinary skills in membrane protein structural biology, DNA nanotechnology, X-ray diffraction and scattering, cryo-electron microscopy and cryo-electron tomography. They have the opportunity to work synergistically to harness X-rays and electrons for structural and functional investigation of biological problems in time and space ...
Actin plays important roles in many biological processes, such as establishing cell polarization, accommodating protruding and retracting activities of motile cells, maintaining the physical integrity of the cell, and sensing environmental forces. All these processes are facilitated by the dynamical and mechanical properties of actin filaments, and their ability to exert or resist against forces generated in a cellular environment.. Actin filaments can assemble into a variety of architectures, including branched and crosslinked networks, parallel bundles, and anti-parallel contractile fibers. These structures provide architectural specificities for different regions of the cell, and can also organize into more complex actin-based machineries. We aim to understand how the native molecular architectures of actin-based cellular processes give rise to force generation and rigidity-sensing. We use cryo-electron tomography, and develop methodologies allowing for quantitative analysis of cellular actin ...
Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co 2 P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and ...
Scientists at the Morgridge Institute for Research have, for the first time, imaged molecular structures vital to how a major class of viruses replicates within infected cells. The research uses pioneering cryo-electron tomography to reveal the complex viral replication process in vivid detail, opening up new avenues to potentially disrupt, dismantle or redirect viral machinery.
The Oryctes nudivirus (OrNV), a natural pathogen of the rhinoceros beetle, has been used successfully to control this pest and could become a sustainable and environmental-friendly tool to battle it if it is effectively produced, formulated, and applied in the field. However, this control strategy suffers from the difficulty to produce sufficient amounts of active virus and by the lack of an effective formulation which would maintain its biological activity when applied in the environment. The main objective of this project is to develop the basis for the stabilization and formulation of the OrNV on a clay-based nanoparticle, which will permit an efficient and practical use of OrNV as biocontrol agent on a large scale. We are using state of the art cryo-electron tomography and nanotechnology to untangle OrNV structure to better understand how it could interact with a clay-based nanoparticle formulation for its stabilization and delivery. This will place us in a much better position to use it ...
Miller S, Wang B, Lo J, DSouza V. A novel mechanism for tRNA and retroviral RNA remodeling during primer annealing. (submitted). Houck-Loomis, B., Durney, M. A., Salguero, C., Shankar, N., Nagle, J. M., Goff, S. P. & DSouza, V. M. (2011). An equilibrium-dependent retroviral mRNA switch regulates translational recoding. Nature 480, 561-4.. Durney, M. A. & DSouza, V. M. (2010). Preformed protein-binding motifs in 7SK snRNA: structural and thermodynamic comparisons with retroviral TAR. J Mol Biol 404, 555-67. [Cover article]. Miyazaki, Y., Irobalieva, R. N., Tolbert, B. S., Smalls-Mantey, A., Iyalla, K., Loeliger, K., DSouza, V., Khant, H., Schmid, M. F., Garcia, E. L., Telesnitsky, A., Chiu, W. & Summers, M. F. (2010). Structure of a conserved retroviral RNA packaging element by NMR spectroscopy and cryo-electron tomography. J Mol Biol 404, 751-72.. DSouza V, Summers MF. 2005. How retroviruses select their genomes. Nature Rev. Microbiol. 3:643-55. Review.. DSouza V, Summers MF. 2004. ...
This project is our contribution to the Cell Migration Consortium. In this project we are using lipid monolayers to form 2-D arrays of adhesion proteins and to assemble cell adhesion complexes for 3-D electron microscopy. The project would involve protein purification and expression and a lot of biochemistry to persuade the proteins to make paracrystalline or crystalline arrays. The proteins that will be investigated include talin, alpha-actinin, vinculin, integrins and many other proteins that have been identified (or will be identified) to be part of cell adhesion complexes. We are also studying the thin margins of cells such as lamellapodia and filopodia by cryoelectron tomography. The type of image processing utilized will depend on the kind of specimen produced. Everything from single particle methods to electron tomography of frozen hydrated specimens will be utilized to obtain the 3-D images. Quasiatomic models will be fit to determine the 3-D arrangement of molecules within ...
Thank you for your interest in spreading the word on Stroke.. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address. ...
November 3, Tue 2009 1:00 pm, MRB 100 Conference Room Dr. Xiongwu Wu Laboratory of Computational Biology, National Heart Lung and Blood Institute, NIH
56) among groups for which eastern people have next. Both G- and C-banding ends for the common Click thank social for operation with the Florida ecology. Although C-banding boundaries have deployed to the scholars of both temperatures( Assis et al. 2002), imports between G-banding faults say more new.
Nephrin is a key functional component of the slit diaphragm, the structurally unresolved molecular filter in renal glomerular capillaries. Abnormal nephrin or its absence results in severe proteinuria and loss of the slit diaphragm. The diaphragm is a thin extracellular membrane spanning the approximately 40-nm-wide filtration slit between podocyte foot processes covering the capillary surface. Using electron tomography, we show that the slit diaphragm comprises a network of winding molecular strands with pores the same size as or smaller than albumin molecules, as demonstrated in humans, rats, and mice. In the network, which is occasionally stratified, immunogold-nephrin antibodies labeled individually detectable globular cross strands, about 35 nm in length, lining the lateral elongated pores. The cross strands, emanating from both sides of the slit, contacted at the slit center but had free distal endings. Shorter strands associated with the cross strands were observed at their base. ...
UCSF Tomography is an integrated software suite that provides full automation from target finding, sequential tomographic data collection, to real-time reconstruction for both single and dual axes as well as automated acquisition of random conical data sets. This software was implemented based upon a novel approach in which the compustage tilting is modeled as geometric rotation. The spatial movement of the sample as a result of stage tilting can be predicted based upon previously collected tomographic images. Therefore, there is no need to collect tracking and focusing images during the entire tomographic data collection. A significant dose saving can thus be achieved and is critical in collecting cryo tilt series. Real-time reconstruction is achieved by calculating a weighted back-projection on a small Linux cluster (five dual-processor computer nodes) concurrently with the UCSF tomography data collection running on the microscopes computer, and using the fiducial-marker free alignment data ...
We host annual/biannual workshops in C-CINA. These include topics like electron tomography and 2D electron crystalloraphy. Check individual pages for more link ...
Sample support grids, typically used for cryo-EM applications, are likewise suitable for 3D electron diffraction experiments. We modified their carbon layer to create a chaotic landscape on the surface that overcomes the missing wedge problem intrinsic to transmission electron techniques.
The primary objectives of this thesis were to investigate and quantify the cellular structure of foamed cement samples at varying densities as well as to demonstrate X-ray computed tomography (CT) as a valuable three dimensional (3D) characterization technique for the investigation of cementitious materials. Three replicate samples were taken from four foamed cement mixes with target densities of 300, 400, 500, and 600 kg/m3, making 12 samples in total. The quantitative analysis included bulk volumetric properties of all 12 samples. One sample from each target density was further investigated to determine the air bubble size distributions that comprise the cellular structure of foamed cement. Following the quantitative analysis, 3D tetrahedral meshes were also created for one sample in every target density. In the analysis of the bulk volumetric properties, the X-ray CT data showed an increase in percent air volume with a decrease in density. The X-ray CT data showed good repeatability as the ...
Extending the capabilities of electron tomography with advanced imaging techniques and novel data processing methods, can augment the information content in three-dimensional (3D) reconstructions from projections taken in the transmission electron microscope (TEM). In this work we present the application of
Abstract. Recently constructed tomographic models of the lateral heterogeneity of elastic properties in the Earths mantle are contrasted in terms of their implications concerning the extent to which the endothermic phase transformation at 660 km depth is influencing the radial style of mixing. Previously published whole mantle and split mantle tomographic reconstructions, SH8/WMI3 and SH8/U4L8 respectively, fit the seismic observations equally well but disagree on the extent to which radial mixing may be impeded across this depth horizon. We show that inferences from seismic tomographic images based on the application of diagnostic functions (global and regional variance spectra and the radial correlation function) lead to the conclusion that the mantle circulation is whole mantle in style if model SH8/WM13 is employed. The split mantle tomographic inversion SHS/U4L8 leads to the contradictory conclusion that the mantle circulation is significantly impeded across the 660 km depth horizon. This ...
Felts RL, Bennett A, Shi D, Freed E, Lifson J, Lowekamp B, Yoo TS, Bliss D, Subramaniam S. 3D Imaging of HIV transmission and entry using electron tomography and ion-abrasion scanning electron microscopy. Three Dimensional Electron Microscopy: Technical Advances and Recent Breakthroughs in 3DEM. Gordon Research Conference; 2008 Jun 15-20; Lucca (Barga), Italy ...
Probolae are a complex manifestation of an extracellular matrix composed of several morphotypes of protein laminates. They surround the mouth opening of some members of the family Cephalobidae, and represent one of many types of cuticular modifications in nematodes. They are complex in terms of their external morphology, ultrastructure and diversity of form within the group. The intention of my work is to gain an understanding of the anatomy and morphogenesis of probolae in a single species of cephalobid nematode. This understanding will be extended to a comparative level by examining more specific aspects of morphogenesis in additional taxa within the framework of a molecular phylogeny. The research will consist of (1) light microscope observations of the life cycle in several taxa, (2) a three dimensional (3D) ultrastructural developmental series of the final molt produced via electron tomography, (3) an estimate of phylogenetic relationships done in collaboration with a molecular systematics ...
We live in a world where anyone can build a CT machine. Yes, anyone. Its made of laser-cut plywood and it looks like a Stargate. Anyone can build an MRI machine. Of course, these machines arent really good enough for medical diagnosis, or good enough to image anything thats alive for that matter. This project for the Hackaday Prize is something else, though. Its biomedical imaging put into a package that is just good enough to image your lungs while theyre still in your body.. The idea behind Spectra is to attach two electrodes to the body (a chest cavity, your gut, or a simulator thats basically a towel wrapped around the inside of a beaker). One of these electrodes emits an AC signal, and the second electrode measures the impedance and phase. Next, move the electrodes and measure again. Do this a few times, and youll be able to perform a tomographic reconstruction of the inside of a chest cavity (or beaker simulator).. Hardware-wise, Spectra uses more than two electrodes, thirty-two on ...
The objectives of this work include automatic recovery and visualization of a 3D chromosome structure from a sequence of 2D tomographic reconstruction images taken through the nucleus of a cell. Structure is v... Authors: Sabarish Babu, Pao-Chuan Liao, Min C. Shin and Leonid V. Tsap. ...
Single computed slice through a tomographic reconstruction of a selectively-stained spiny dendrite. This medium spiny neuron was contained in a thick...
This document is part of Subvolume A Gases in Gases, Liquids and their Mixtures of Volume 15 Diffusion in Gases, Liquids and Electrolytes of Landolt-Börnstein Group IV Physical Chemistry. It is part of ...
Principal Investigator:KONO Kimitoshi, Project Period (FY):1998 - 1999, Research Category:Grant-in-Aid for Scientific Research (A)., Section:一般, Research Field:固体物性II(磁性・金属・低温)
Get an introduction to some of the basic chemical, physical and biological processes responsible for the survival and growth of humans and other complex life forms, bacteria and viruses. Explore the basic chemistry and overall structure of the most important biological macromolecules, including the study of enzyme catalysis; cellular architecture; intermediary metabolism; and special processes such as photosynthesis, biological oxidation and energy production. You also study the various ways that biological systems react to their environment. Learn to apply these topics to aspects of exercise, nutrition or inborn errors of metabolism.
Rigidity of a spherical capsule switches the localization of encapsulated particles between inner and peripheral regions under crowding condition: Simple model on cellular architecture ...
Our clinic will evaluate your teeth conditions with MRI scan, tomograms, X-rays, and other procedures to recommend a right treatment program.
Microtubules are dynamic cytoskeletal structures important for cell division, polarity, and motility and are therefore major targets for anticancer and antiparasite drugs. In the invasive forms of apicomplexan parasites, which are highly polarized and often motile cells, exceptionally stable subpellicular microtubules determine the shape of the parasite, and serve as tracks for vesicle transport. We used cryoelectron tomography to image cytoplasmic structures in three dimensions within intact, rapidly frozen Plasmodium sporozoites. This approach revealed microtubule walls that are extended at the luminal side by an additional 3 nm compared to microtubules of mammalian cells. Fourier analysis revealed an 8-nm longitudinal periodicity of the luminal constituent, suggesting the presence of a molecule interacting with tubulin dimers. In silico generation and analysis of microtubule models confirmed this unexpected topology. Microtubules from extracted sporozoites and Toxoplasma gondii tachyzoites ...