scholarly journals Reversible embedment cytochemistry (REC): a versatile method for the ultrastructural analysis and affinity labeling of tissue sections.

1986 ◽  
Vol 34 (2) ◽  
pp. 177-188 ◽  
Author(s):  
G Gorbsky ◽  
G G Borisy
Keyword(s):  
Electron Microscopy ◽  
Cultured Cells ◽  
Cell Structure ◽  
Linear Polymers ◽  
Fixed Tissue ◽  
Affinity Labels ◽  
Tissue Sections ◽  
Culture Cells ◽  
Transmission Electron ◽  
Critical Point Drying

Reversible embedment cytochemistry (REC) is a new method for revealing cellular ultrastructure and for improving access of intracellular targets to macromolecular affinity labels. Fully polymerized polymethylmethacrylate was dissolved in dichloromethane and infiltrated into fixed tissue-culture cells and tissues. After evaporation of the solvent, samples were left in hard plastic. Samples were thus embedded without exposure to chemical polymerization reactions that might damage tissue ultrastructure or antigenicity. Glass or diamond knives fitted with water troughs were used to cut sections 30-1000 nm thick. Since polymethylmethacrylate is composed of linear polymers that are not covalently crosslinked, the plastic was easily extracted from the sections by immersion in solvent. Subsequently, various preparative methods, including negative staining, critical point-drying, and platinum-carbon rotary shadowing, were used to provide detailed images of well-preserved cell structure for conventional and high-voltage transmission electron microscopy. Fluorescein-conjugated affinity labels were used to obtain subcellular distributions of target molecules in semi-thick sections of cultured cells and tissues for light microscopy. Colloidal gold-labeled antibodies were used to localize microtubules in sections of cultured cells by electron microscopy. REC is a versatile method that should find wide application in many studies of cellular function.

scholarly journals Imaging heterostructured quantum dots in cultured cells with epifluorescence and transmission electron microscopy

2011 ◽  
Author(s):  
Erin M. Rivera ◽  
Casilda Trujillo Provencio ◽  
Andrea Steinbrueck ◽  
Pawan Rastogi ◽  
Allison Dennis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Cultured Cells ◽  
Transmission Electron

scholarly journals Cells Connected by Tiny Tunnels

2004 ◽  
Vol 12 (5) ◽  
pp. 3-7
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Wheat Germ ◽  
Cultured Cells ◽  
Cell Communication ◽  
Tunneling Nanotubes ◽  
Pheochromocytoma Cells ◽  
Intracellular Communication ◽  
Transmission Electron ◽  
Multicellular Organisms

Intracellular communication is imperative for multicellular organisms. Such devices as synapses and gap junctions have been recognized for decades. Now Amin Rustom, Raiser Saffrich, Ivanka Markovic, Paul Walther, and Hans-Hermann Gerdes have described a new model of cell-to-cell communication.While looking at PC12 (rat pheochromocytoma) cells in the presence of fluorescently labeled wheat germ agglutinin, Rustom et al. observed relatively long connections extending between cells. These structures were 50 to 200 nm in diameter and up to several cell diameters in length and were named tunneling nanotubes (TNTs). TNTs were subsequently found connecting cultured cells from other lines. They were consistently positioned along the smallest distance between the cells, did not contact the substrate, and occasionally were branched. TNTs immunostained positive for actin, but did not contain microtubules. Scanning and transmission electron microscopy definitively established that a TNT represented a seamless continuity of the plasma membrane from one cell to another.

scholarly journals CONCOMITANT EFFECTS OF INSULIN ON SURFACE MEMBRANE CONFORMATION AND POLYSOME PROFILES OF SERUM-STARVED BALB/C 3T3 FIBROBLASTS

1974 ◽  
Vol 61 (1) ◽  
pp. 95-106 ◽  
Author(s):  
R. Blair Evans ◽  
Vera Morhenn ◽  
Albert L. Jones ◽  
Gordon M. Tomkins
Keyword(s):  
Electron Microscopy ◽  
Insulin Treatment ◽  
Cultured Cells ◽  
Unit Area ◽  
Surface Membrane ◽  
Serum Starvation ◽  
3T3 Fibroblasts ◽  
Transmission Electron ◽  
Polysome Profile ◽  
Logarithmic Growth

By scanning and transmission electron microscopy we have shown that insulin rapidly reversed changes in surface membrane conformation and polysome profile induced by the transfer of actively growing Balb/c 3T3 fibroblasts from a serum-containing to a serum-free medium. Morphometric analysis of polysome profiles revealed a 94% aggregation of total f ribosomes during logarithmic growth. This figure fell to 78% after 18 h of serum starvation. The number of f ribosomes per unit area of cytoplasm also fell. 1 h of insulin treatment restored aggregation to 92% and increased the number of f ribosomes per unit area of cytoplasm by 22%. Scanning electron microscopy of logarithmically growing cells revealed an abundance of surface microvilli, whereas serum starvation promoted a smooth surface with few microvilli. After 1 h of insulin treatment, microvilli reappeared with a distribution and subcellular organization characteristic of exponential growth. This study shows the combined and rapid effect of insulin on the regulation of polysome formation and the promotion of a specific surface membrane conformation in cultured cells. The observations are consistent with the knowledge that insulin, acting on the surface membrane, can influence such parameters as membrane transport, and the rates of protein and RNA synthesis.

scholarly journals Fluorescence and electron microscopy to visualize the intracellular fate of nanoparticles for drug delivery

2016 ◽  
Vol 60 (2) ◽  
Author(s):  
M. Costanzo ◽  
F. Carton ◽  
A. Marengo ◽  
G. Berlier ◽  
B. Stella ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Cultured Cells ◽  
Cell System ◽  
Functional Relationships ◽  
Cell Internalization ◽  
Transmission Electron ◽  
Intracellular Fate

<p>In order to design valid protocols for drug release <em>via</em> nanocarriers, it is essential to know the mechanisms of cell internalization, the interactions with organelles, and the intracellular permanence and degradation of nanoparticles (NPs) as well as the possible cell alteration or damage induced. In the present study, the intracellular fate of liposomes, polymeric NPs and mesoporous silica NPs (MSN) has been investigated in an <em>in vitro</em> cell system by fluorescence and transmission electron microscopy. The tested nanocarriers proved to be characterized by specific interactions with the cell: liposomes enter the cells probably by fusion with the plasma membrane and undergo rapid cytoplasmic degradation; polymeric NPs are internalized by endocytosis, occur in the cytoplasm both enclosed in endosomes and free in the cytosol, and then undergo massive degradation by lysosome action; MSN are internalized by both endocytosis and phagocytosis, and persist in the cytoplasm enclosed in vacuoles. No one of the tested nanocarriers was found to enter the nucleus. The exposure to the different nanocarriers did not increase cell death; only liposomes induced a reduction of cell population after long incubation times, probably due to cell overloading. No subcellular damage was observed to be induced by polymeric NPs and MSN, whereas transmission electron microscopy revealed cytoplasm alterations in liposome-treated cells. This important information on the structural and functional relationships between nanocarriers designed for drug delivery and cultured cells further proves the crucial role of microscopy techniques in nanotechnology.</p>

scholarly journals SURFACE STRUCTURE OF ISOLATED NEURONS

1970 ◽  
Vol 47 (2) ◽  
pp. 319-331 ◽  
Author(s):  
Anders Hamberger ◽  
Hans-Arne Hansson ◽  
Johan Sjöstrand
Keyword(s):  
Electron Microscopy ◽  
Hypoglossal Nerve ◽  
Light And Electron Microscopy ◽  
Neuronal Cell ◽  
Spherical Particles ◽  
Hypoglossal Nucleus ◽  
Isolated Neurons ◽  
Tissue Sections ◽  
Neuronal Cell Bodies ◽  
Transmission Electron

Freehand, isolated neuronal perikarya from the hypoglossal nucleus of the rabbit have been examined with light-and electron-microscopy (transmission and scanning). The surface of the cell bodies was largely covered with spherical particles which were 0.5–2 µ in diameter. Transmission electron microscopy proved that the spherical particles were synaptic nerve terminals. Crush of the hypoglossal nerve which leads to chromatolysis and swelling of the neuronal cell bodies results in a conspicuous reduction in the number of terminals attached to the surface of hypoglossal neurons. This effect was observed both for isolated neurons and in tissue sections. The effect is considered in relation to earlier reported variations in the adherence of neuropil to isolated neuronal perikarya. The functional importance of nerve ending detachment in connection with nerve injury is discussed.

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