Electron Microscopy of Cytoplasmic Contractile Proteins

1978 ◽  
Vol 36 (3) ◽  
pp. 606-614 ◽  
Author(s):  
T.D. Pollard ◽  
P. Maupin
Keyword(s):  
Electron Microscopy ◽  
Actin Filaments ◽  
Three Dimensional ◽  
Uranyl Acetate ◽  
Contractile Proteins ◽  
Dimensional Structure ◽  
X Ray Diffraction ◽  
Cytoplasmic Matrix ◽  
Computer Image Processing ◽  
Nonmuscle Cells

In this paper we review some of the contributions that electron microscopy has made to the analysis of actin and myosin from nonmuscle cells. We place particular emphasis upon the limitations of the ultrastructural techniques used to study these cytoplasmic contractile proteins, because it is not widely recognized how difficult it is to preserve these elements of the cytoplasmic matrix for electron microscopy. The structure of actin filaments is well preserved for electron microscope observation by negative staining with uranyl acetate (Figure 1). In fact, to a resolution of about 3nm the three-dimensional structure of actin filaments determined by computer image processing of electron micrographs of negatively stained specimens (Moore et al., 1970) is indistinguishable from the structure revealed by X-ray diffraction of living muscle.

scholarly journals Synthesis, crystal structure, and thermal properties of poly[aqua(μ5-2,5-dicarboxybenzene-1,4-dicarboxylato)strontium]

2020 ◽  
Vol 76 (3) ◽  
pp. 354-359
Author(s):  
Samia Mokhtari ◽  
Chahrazed Trifa ◽  
Sofiane Bouacida ◽  
Chaouki Boudaren ◽  
Mohammed S.M. Abdelbaky ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thermal Analysis ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Tetracarboxylic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylate Groups ◽  
Scanning Electron

A coordination polymer formulated as [Sr(H2BTEC)(H2O)] n (H4BTEC = benzene-1,2,4,5-tetracarboxylic acid, C10H6O8), was synthesized hydrothermally and characterized by single-crystal and powder X-ray diffraction, scanning electron microscopy and thermal analysis. Its crystal structure is made up of a zigzag inorganic chain formed by edge-sharing of [SrO8] polyhedra running along [001]. Adjacent chains are connected to each other via the carboxylate groups of the ligand, resulting in a double-layered network extending parallel to (100). O—H...O hydrogen bonds of medium-to-weak strength between the layers consolidate the three-dimensional structure. One of the carboxylic OH functions was found to be disordered over two sets of sites with half-occupancy.

scholarly journals Three-Dimensional Structure of Cytochrome c Nitrite Reductase As Determined by Cryo-Electron Microscopy

Acta Naturae ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 48-56 ◽  
Author(s):  
T. N. Baymukhametov ◽  
Yu. M. Chesnokov ◽  
E. B. Pichkur ◽  
K. M. Boyko ◽  
T. V. Tikhonova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cytochrome C ◽  
Nitrite Reductase ◽  
Three Dimensional ◽  
Structural Heterogeneity ◽  
Dimensional Structure ◽  
Side Chain ◽  
X Ray Diffraction ◽  
Cytochrome C Nitrite Reductase ◽  
Cryo Electron Microscopy

The structure of cytochrome c nitrite reductase from the bacterium Thioalkalivibrio nitratireducens was determined by cryo-electron microscopy (cryo-EM) at a 2.56 resolution. Possible structural heterogeneity of the enzyme was assessed. The backbone and side-chain orientations in the cryo-EM-based model are, in general, similar to those in the high-resolution X-ray diffraction structure of this enzyme.

scholarly journals Facile Fabrication of Three-Dimensional Fusiform-Like α-Fe2O3 for Enhanced Photocatalytic Performance

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2650
Author(s):  
Moyan Li ◽  
Hongjin Liu ◽  
Shaozhi Pang ◽  
Pengwei Yan ◽  
Mingyang Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Raw Materials ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Photocatalytic Decolorization ◽  
Transmission Electron ◽  
Facile Fabrication

α-Fe2O3 fusiform nanorods were prepared by a simple hydrothermal method employing the mixture of FeCl3·6H2O and urea as raw materials. The samples were examined by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and UV–vis diffuse reflectance spectra (UV–DRS). Its visible-light photocatalytic performances were evaluated by photocatalytic decolorization methylene blue (MB) in visible light irradiation. It was found that pure phase α-Fe2O3 nanorods with a length of about 125 nm and a diameter of 50 nm were successfully synthesized. The photocatalytic decolorization of MB results indicated that α-Fe2O3 nanorods showed higher photocatalytic activity than that of commercial Fe2O3 nanoparticles—these are attributed to its unique three-dimensional structure and lower electron-hole recombination rate.

High-voltage electron microscopy of maxillary gland of spirochete-infected brine shrimp: lesion of efferent tubule

1988 ◽  
Vol 46 ◽  
pp. 362-363
Author(s):  
G. E. Tyson ◽  
M. J. Song
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Brine Shrimp ◽  
Natural Populations ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Infected Adult

Natural populations of the brine shrimp, Artemia, may possess spirochete- infected animals in low numbers. The ultrastructure of Artemia's spirochete has been described by conventional transmission electron microscopy. In infected shrimp, spirochetal cells were abundant in the blood and also occurred intra- and extracellularly in the three organs examined, i.e. the maxillary gland (segmental excretory organ), the integument, and certain muscles The efferent-tubule region of the maxillary gland possessed a distinctive lesion comprised of a group of spirochetes, together with numerous small vesicles, situated in a cave-like indentation of the base of the tubule epithelium. in some instances the basal lamina at a lesion site was clearly discontinuous. High-voltage electron microscopy has now been used to study lesions of the efferent tubule, with the aim of understanding better their three-dimensional structure.Tissue from one maxillary gland of an infected, adult, female brine shrimp was used for HVEM study.

Confocal laser microscopy of impregnated central nervous system tissue

1988 ◽  
Vol 46 ◽  
pp. 94-95
Author(s):  
J.N. Turner ◽  
M. Siemens ◽  
D. Szarowski ◽  
D.N. Collins
Keyword(s):  
Electron Microscopy ◽  
Central Nervous System ◽  
Nervous System ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Confocal Laser ◽  
High Contrast ◽  
Central Nervous System Tissue ◽  
Tissue Samples ◽  
Reflected Light

A classic preparation of central nervous system tissue (CNS) is the Golgi procedure popularized by Cajal. The method is partially specific as only a few cells are impregnated with silver chromate usualy after osmium post fixation. Samples are observable by light (LM) or electron microscopy (EM). However, the impregnation is often so dense that structures are masked in EM, and the osmium background may be undesirable in LM. Gold toning is used for a subtle but high contrast EM preparation, and osmium can be omitted for LM. We are investigating these preparations as part of a study to develop correlative LM and EM (particularly HVEM) methodologies in neurobiology. Confocal light microscopy is particularly useful as the impregnated cells have extensive three-dimensional structure in tissue samples from one to several hundred micrometers thick. Boyde has observed similar preparations in the tandem scanning reflected light microscope (TSRLM).

Structural Role of rRNAs on the Ribosomal Subunits from E. Coli by Scanning Transmission Electron Microscopy

1981 ◽  
Vol 39 ◽  
pp. 424-425
Author(s):  
M. Boublik ◽  
N. Robakis ◽  
J.S. Wall
Keyword(s):  
Three Dimensional ◽  
Uranyl Acetate ◽  
Dimensional Structure ◽  
Electron Microscopic ◽  
Ribosomal Subunits ◽  
E Coli ◽  
Freeze Dried ◽  
16S Rna ◽  
Scanning Transmission ◽  
And Function

The three-dimensional structure and function of biological supramolecular complexes are, in general, determined and stabilized by conformation and interactions of their macromolecular components. In the case of ribosomes, it has been suggested that one of the functions of ribosomal RNAs is to act as a scaffold maintaining the shape of the ribosomal subunits. In order to investigate this question, we have conducted a comparative TEM and STEM study of the structure of the small 30S subunit of E. coli and its 16S RNA.The conventional electron microscopic imaging of nucleic acids is performed by spreading them in the presence of protein or detergent; the particles are contrasted by electron dense solution (uranyl acetate) or by shadowing with metal (tungsten). By using the STEM on freeze-dried specimens we have avoided the shearing forces of the spreading, and minimized both the collapse of rRNA due to air drying and the loss of resolution due to staining or shadowing. Figure 1, is a conventional (TEM) electron micrograph of 30S E. coli subunits contrasted with uranyl acetate.

scholarly journals Capturing Enveloped Viruses on Affinity Grids for Downstream Cryo-Electron Microscopy Applications

2013 ◽  
Vol 20 (1) ◽  
pp. 164-174 ◽  
Author(s):  
Gabriella Kiss ◽  
Xuemin Chen ◽  
Melinda A. Brindley ◽  
Patricia Campbell ◽  
Claudio L. Afonso ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Measles Virus ◽  
Influenza A ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Nitrilotriacetic Acid ◽  
Dimensional Structure ◽  
Enveloped Viruses ◽  
Cryo Electron Microscopy ◽  
Human Immunodeficiency Virus Virus

AbstractElectron microscopy (EM), cryo-electron microscopy (cryo-EM), and cryo-electron tomography (cryo-ET) are essential techniques used for characterizing basic virus morphology and determining the three-dimensional structure of viruses. Enveloped viruses, which contain an outer lipoprotein coat, constitute the largest group of pathogenic viruses to humans. The purification of enveloped viruses from cell culture presents certain challenges. Specifically, the inclusion of host-membrane-derived vesicles, the complete destruction of the viruses, and the disruption of the internal architecture of individual virus particles. Here, we present a strategy for capturing enveloped viruses on affinity grids (AG) for use in both conventional EM and cryo-EM/ET applications. We examined the utility of AG for the selective capture of human immunodeficiency virus virus-like particles, influenza A, and measles virus. We applied nickel-nitrilotriacetic acid lipid layers in combination with molecular adaptors to selectively adhere the viruses to the AG surface. This further development of the AG method may prove essential for the gentle and selective purification of enveloped viruses directly onto EM grids for ultrastructural analyses.

scholarly journals Determination of the alpha-actinin-binding site on actin filaments by cryoelectron microscopy and image analysis.

1994 ◽  
Vol 126 (2) ◽  
pp. 433-443 ◽  
Author(s):  
A McGough ◽  
M Way ◽  
D DeRosier
Keyword(s):  
Image Analysis ◽  
Smooth Muscle ◽  
Binding Sites ◽  
Actin Filaments ◽  
Three Dimensional ◽  
Actin Binding ◽  
Dimensional Structure ◽  
Outer Face ◽  
Actin Binding Domain

The three-dimensional structure of actin filaments decorated with the actin-binding domain of chick smooth muscle alpha-actinin (alpha A1-2) has been determined to 21-A resolution. The shape and location of alpha A1-2 was determined by subtracting maps of F-actin from the reconstruction of decorated filaments. alpha A1-2 resembles a bell that measures approximately 38 A at its base and extends 42 A from its base to its tip. In decorated filaments, the base of alpha A1-2 is centered about the outer face of subdomain 2 of actin and contacts subdomain 1 of two neighboring monomers along the long-pitch (two-start) helical strands. Using the atomic model of F-actin (Lorenz, M., D. Popp, and K. C. Holmes. 1993. J. Mol. Biol. 234:826-836.), we have been able to test directly the likelihood that specific actin residues, which have been previously identified by others, interact with alpha A1-2. Our results indicate that residues 86-117 and 350-375 comprise distinct binding sites for alpha-actinin on adjacent actin monomers.

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