scholarly journals Electron microscopy of cervical, gastric and bronchial mucus glycoproteins

1986 ◽  
Vol 239 (1) ◽  
pp. 147-153 ◽  
Author(s):  
J K Sheehan ◽  
K Oates ◽  
I Carlstedt
Keyword(s):  
Electron Microscopy ◽  
Proteinase Inhibitors ◽  
Gradient Centrifugation ◽  
Uranyl Acetate ◽  
Gastric Mucus ◽  
Bronchial Mucus ◽  
Mucus Gel ◽  
Macromolecular Architecture ◽  
Mucus Glycoproteins ◽  
Low Shear

Mucus glycoproteins (mucins) were obtained from human cervical and pig gastric mucus as well as from chronic-bronchitic sputum after low-shear extraction. The mucus gel was solubilized in guanidinium chloride supplemented with proteinase inhibitors, and the macromolecules were purified by using isopycnic density-gradient centrifugation. The macromolecules were spread in monolayers of benzyldimethylalkyl-ammonium chloride and studied with electron microscopy after staining with uranyl acetate and/or shadowing with platinum/carbon. The mucins appeared as flexible linear threads with lengths varying from approx. 200 nm to about 400 nm. No regularly branched or star-shaped structures were observed. The macromolecular architecture of cervical, respiratory and gastric mucins is thus similar.

scholarly journals Mucus glycoproteins from cystic fibrotic sputum. Macromolecular properties and structural ‘architecture’

1991 ◽  
Vol 276 (3) ◽  
pp. 667-675 ◽  
Author(s):  
D J Thornton ◽  
J K Sheehan ◽  
H Lindgren ◽  
I Carlstedt
Keyword(s):  
Electron Microscopy ◽  
Density Gradient ◽  
Proteinase Inhibitors ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Buoyant Density ◽  
Gel Chromatography ◽  
Guanidinium Chloride ◽  
Gel Phase ◽  
Mucus Glycoproteins

Mucus glycoproteins (mucins) were isolated from sputum of patients with cystic fibrosis (CF) after separation into sol and gel phases. The mucus gel was solubilized with gentle stirring in 6 M-guanidinium chloride supplemented with proteinase inhibitors, and purification of mucins was subsequently achieved by isopycnic density-gradient centrifugation in CsCl/guanidinium chloride. Density-gradient centrifugation also revealed a heterogeneity of the macromolecules, the pattern of which varied between individuals, and mucins from the gel phase was pooled as ‘heavy’ and ‘light’ fractions. Gel chromatography on Sepharose CL-2B showed that the heavy fraction contained a larger proportion of smaller species than the ‘light’ fraction and that the gel phase mucins were much larger than those from the sol. An apparently homogeneous high-Mr mucin population from one individual contained approx. 70% (w/w) carbohydrate, the major sugars being N-acetylglucosamine (17.8%), N-acetylgalactosamine (6.7%), galactose (20.7%), fucose (13.2%) and sialic acid (11.4%). These mucins had an S020.w of 47 S, and an Mr of 15 x 10(6) -20 x 10(6), and rate-zonal centrifugation revealed a polydisperse size distribution [range (5-30) x 10(6)] with a weight-average Mr of 17 x 10(6). The whole mucins were visualized with electron microscopy as linear and apparently flexible threads, disperse in size. Reduction produced subunits which were included on Sepharose CL-2B, and subsequent trypsin digestion yielded high-Mr glycopeptides which were further retarded. The size distributions and fragmentation patterns of mucin from two other CF patients were the same, as studied by gel chromatography, rate-zonal centrifugation and electron microscopy. We conclude that CF mucins are heterogeneous in both size and buoyant density and that the various populations, though differing in buoyant density, share the same architecture and macromolecular properties and are, in this respect, similar to mucins from normal respiratory secretions [Thornton, Davies, Kraayenbrink, Richardson, Sheehan & Carlstedt (1990) Biochem. J. 265, 179-186] and human cervical mucus [Carlstedt & Sheehan (1989) SEB Symp. XLIII 289-316].

scholarly journals Mucus glycoproteins from ‘normal’ human tracheobronchial secretion

1990 ◽  
Vol 265 (1) ◽  
pp. 179-186 ◽  
Author(s):  
D J Thornton ◽  
J R Davies ◽  
M Kraayenbrink ◽  
P S Richardson ◽  
J K Sheehan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lower Respiratory Tract ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Gel Chromatography ◽  
Guanidinium Chloride ◽  
Minor Surgery ◽  
Normal Human ◽  
Macromolecular Architecture ◽  
Mucus Glycoproteins

Mucous secretions were collected from tracheas of patients undergoing minor surgery under general anaesthesia with tracheal intubation, and mucus glycoproteins were isolated by using isopycnic density-gradient centrifugation in CsCl/guanidinium chloride. ‘Whole’ mucins were excluded from a Sepharose CL-2B gel, whereas subunits obtained after reduction were included. Trypsin digestion of subunits afforded high-Mr glycopeptides (T-domains), which were further included in the gel. The latter fragments are heterogeneous and comprise two or three populations, as indicated by gel chromatography and ion-exchange h.p.l.c. Rate-zonal centrifugation showed that the ‘whole’ mucins are polydisperse in size, with a weight-average Mr of (14-16) x 10(6). The macromolecules were observed by electron microscopy, as linear and apparently flexible thread-like structures. Subunits and T-domains had weight-average contour lengths of 490 nm and 160 nm respectively. It is concluded that mucus glycoproteins are present in secretions from the healthy lower respiratory tract. The ‘whole’ tracheal mucins are assembled from subunits, which in turn can be fragmented into high-Mr glycopeptides corresponding to the oligosaccharide domains typically found in mucus glycoproteins. The size and macromolecular architecture of the tracheal mucins is thus similar to that observed for mucins from human cervical mucus, chronic bronchitic sputum and pig stomach, providing yet another example of this general design of these macromolecules, i.e. subunits assembled end-to-end into very large linear and flexible macromolecules.

Uranyl Acetate and Rotary Shadowing to Increase the Contrast of Small Aggregated Virus Particles

1969 ◽  
Vol 27 ◽  
pp. 424-425
Author(s):  
Lee F. Ellis ◽  
Richard M. Van Frank ◽  
Walter J. Kleinschmidt
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Uranyl Acetate ◽  
Interferon Inducer ◽  
Virus Particles ◽  
Staining Methods ◽  
Rotary Shadowing

The extract from Penicillum stoliniferum, known as statolon, has been purified by density gradient centrifugation. These centrifuge fractions contained virus particles that are an interferon inducer in mice or in tissue culture. Highly purified preparations of these particles are difficult to enumerate by electron microscopy because of aggregation. Therefore a study of staining methods was undertaken.

scholarly journals Peptides of human bronchial mucus glycoproteins. Size determination by electron microscopy and by biosynthetic experiments

1987 ◽  
Vol 248 (1) ◽  
pp. 189-195 ◽  
Author(s):  
T Marianne ◽  
J M Perini ◽  
J J Lafitte ◽  
N Houdret ◽  
F R Pruvot ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Proteinase Inhibitors ◽  
Polyacrylamide Gel Electrophoresis ◽  
Length Distribution ◽  
Molecular Size ◽  
Pulse Labelling ◽  
Bronchial Mucosa ◽  
Chase Period ◽  
Bronchial Mucus ◽  
Multiple Treatments

Secreted human bronchial mucins, directly collected from macroscopically healthy bronchial mucosa, were prepared in the presence of six proteinase inhibitors, and analysed by electron microscopy. These mucins were similar in length distribution to molecules prepared from sputum [Slayter, Lamblin, Le Treut, Galabert, Houdret, Degand & Roussel (1984) Eur. J. Biochem. 142, 209-218], although they were a little longer, their lengths ranging up to about 1,650 nm. This length corresponds to an extended mucin peptide of about 450 kDa. In order to compare these peptide lengths with the molecular size of biosynthetic precursors, an antiserum raised against trifluoromethanesulphonic acid-treated highly glycosylated regions of human bronchial mucins was used to isolate mucin precursors synthesized in explants of human bronchial mucosa during pulse-labelling with [3H]threonine or [3H]glucosamine. A main precursor labelled with [3H]threonine and with an apparent molecular mass of about 400 kDa was detected by fluorography following SDS/polyacrylamide-gel electrophoresis. This band was observed as early as 20 min; it was more intense after a 40 min chase and had disappeared after a chase period of 280 min in unlabelled medium, presumably owing to glycosylation. Much fainter bands at about 200 kDa and between 200 and 400 kDa, also labelled with [3H]threonine, were observed mainly after a 40 min chase and had disappeared after a 280 min chase. None of these bands was labelled with [3H]glucosamine, nor did they disappear after multiple treatments with immobilized lectins. After a 280 min chase, [3H]threonine-labelled material appeared in the stacking gel, which also contained [3H]glucosamine label. The results indicate that the 200-400 kDa species are mucin precursors, whose size is comparable with that obtained by electron microscopy for respiratory mucins collected directly from the macroscopically healthy bronchial mucosa.

scholarly journals The macromolecular structure of human cervical-mucus glycoproteins. Studies on fragments obtained after reduction of disulphide bridges and after subsequent trypsin digestion

1983 ◽  
Vol 213 (2) ◽  
pp. 427-435 ◽  
Author(s):  
I Carlstedt ◽  
H Lindgren ◽  
J K Sheehan
Keyword(s):  
Proteinase Inhibitors ◽  
Gradient Centrifugation ◽  
Cervical Mucus ◽  
Trypsin Digestion ◽  
Radius Of Gyration ◽  
Guanidinium Chloride ◽  
Disulphide Bonds ◽  
Tentative Model ◽  
The Relationship ◽  
Mucus Glycoproteins

Human cervical-mucus glycoproteins (mucins) were extracted with 6 M-guanidinium chloride in the presence of proteinase inhibitors and purified by isopycnic density-gradient centrifugation. The whole mucins (Mr approx. 10 × 10(6] were degraded into ‘subunits’ (Mr approx. 2 × 10(6] by reduction of disulphide bonds. Trypsin digestion of the ‘subunits’ produced glycopeptides with Mr approx. 380000, which appear to be rod-like with a length of approx. 105 nm. The relationship between the radius of gyration and the Mr value obtained by light-scattering for whole mucins, ‘subunits’ and ‘domains’ suggest that cervical-mucus glycoproteins are linear flexible macromolecules composed of, on the average, four or five ‘domains’/subunit and four subunits/whole mucin macromolecule. The shape-dependent particle scattering function for the whole mucins and the ‘subunits’ are in accordance with that of a linear flexible chain. No evidence for a branched or a star-like structure was found. A tentative model for cervical mucins is proposed.

Electron Microscopy of a Tumor Virus RNA

1975 ◽  
Vol 33 ◽  
pp. 646-647
Author(s):  
D. Evenson ◽  
A. Scotto ◽  
A. Pavlovec ◽  
M. Hamilton ◽  
E. de Harven
Keyword(s):  
Electron Microscopy ◽  
Ammonium Acetate ◽  
Leukemia Virus ◽  
Gradient Centrifugation ◽  
Uranyl Acetate ◽  
Avian Myeloblastosis Virus ◽  
Virus Rna ◽  
Friend Leukemia ◽  
Tumor Virus ◽  
Friend Leukemia Virus

The structure of Friend leukemia virus (FLV) has been studied by electron microscopy. The virus was harvested from the plasma of infected mice and purified by techniques including differential velocity and isopycnic sucrose gradient centrifugation. Viral nucleic acid was isolated using GuHCl followed by precipitation with ethanol and resuspension in 1 mM dithiothreitol. In initial experiments, the RNA solution was diluted 1:10 into either H2O or 4-8 M urea. Prior to spreading, 1 M ammonium acetate and cytochrome c were added to a final concentration of 0.4 M and 0.01% respectively. Fifty μ1 of this mixture was spread using a glass slide inclined in a ten cm2 trough filled with 15 mM ammonium acetate. Samples were picked up on collodion filmed grids, stained with uranyl acetate and rotary shadowed with Pt:Pd. This method is very similar to the conditions used to study the RNA of avian myeloblastosis virus, murine leukemia virus, and mammary tumor virus (MTV).

scholarly journals Isolation and characterization of human cervical-mucus glycoproteins

1983 ◽  
Vol 211 (1) ◽  
pp. 13-22 ◽  
Author(s):  
I Carlstedt ◽  
H Lindgren ◽  
J K Sheehan ◽  
U Ulmsten ◽  
L Wingerup
Keyword(s):  
Density Gradient ◽  
Proteinase Inhibitors ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Disc Electrophoresis ◽  
Guanidinium Chloride ◽  
Molecular Weights ◽  
Isolation And Characterization ◽  
Mucus Glycoproteins

Mucus glycoproteins (mucins) were extracted from human cervical pregnancy mucus by 6 M-guanidinium chloride in the presence of proteinase inhibitors. Purification was subsequently achieved by isopycnic density-gradient centrifugation in CsCl/ guanidinium chloride gradients. The purified macromolecules represented approx. 85% of the total and were devoid of nucleic acids and proteins, as judged by analytical density-gradient centrifugation, disc electrophoresis and u.v. spectroscopy. Sedimentation-velocity centrifugation revealed a single unimodal peak with S20,W 50.1S in 0.2M-NaCl and 37.0S in 6 M-guanidinium chloride. Molecular weights obtained by light-scattering were 9.7 × 10(6) and 5.9 × 10(6) in 0.2M-NaCl and 6 M-guanidinium chloride respectively. The chemical analyses were typical of those of epithelial mucins. The macromolecules contained approx. 20% (w/w) of protein, and 65% (w/w) was accounted for as carbohydrate. Serine and threonine constituted 32 mol/100 mol and proline 10 mol/100 mol of the amino acids. The major sugars found were N-acetylglucosamine (12.8%), N-acetylgalactosamine (9.7%), galactose (18.7%), sialic acid (15.0%) and fucose (7.5%).

scholarly journals Characterization of pig colonic mucins

1996 ◽  
Vol 316 (3) ◽  
pp. 937-942 ◽  
Author(s):  
Fiona J. J. FOGG ◽  
David A. HUTTON ◽  
Kornelia JUMEL ◽  
Jeffrey P. PEARSON ◽  
Stephen E. HARDING ◽  
...  
Keyword(s):  
Amino Acids ◽  
Proteinase Inhibitors ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Colonic Mucin ◽  
Cscl Density Gradient ◽  
Mucin Genes ◽  
Mucus Gel ◽  
Hydrophobic Amino Acids

Pig colonic mucins isolated from the adherent mucus gel in the presence of proteinase inhibitors were solubilized by homogenization and the component mucins fractionated by CsCl density-gradient centrifugation. Polymeric and reduced pig colonic mucin were both largely excluded on Sepharose CL-2B, papain-digested colonic mucin was included. The Mr values of polymeric, reduced and digested mucins were 5.5×106, 2.1×106 and 0.6×106 respectively. This suggests that pig colonic mucin is comprised of 2–3 subunits, each subunit containing 3–4 glycosylated regions. The intrinsic viscosities of polymeric, reduced and digested mucin were 240 ml·g-1, 100 ml·g-1 and 20 ml·g-1 respectively. Polymeric pig colonic mucin comprised 16% protein per mg of glycoprotein and was rich in serine, threonine and proline (43% of total amino acids). There were approx. 150 disulphide bridges and 53 free thiol groups per mucin polymer. A seventh of the protein content was lost on reduction. This protein was particularly rich in proline and the hydrophobic amino acids. Papain-digested pig colonic mucin contained 11% protein per mg of glycoprotein and was rich in serine, threonine, glutamate and aspartate. All types of amino acids with the exception of aspartate were lost on digestion. The amino acid analysis of the proteolytically digested regions of pig colonic mucin are markedly different to the tandem repeat regions of the human mucin genes shown to be expressed in the colon.

Platinum Compounds as Stains for Electron Microscopy

1974 ◽  
Vol 32 ◽  
pp. 230-231
Author(s):  
S. K. Aggarwal ◽  
P. McAllister ◽  
R. W. Wagner ◽  
B. Rosenberg
Keyword(s):  
Electron Microscopy ◽  
Hela Cells ◽  
Uranyl Acetate ◽  
Sarcoma 180 ◽  
Platinum Compounds ◽  
Kb Cells ◽  
En Bloc ◽  
Human Lymphoma ◽  
Ultrathin Sections ◽  
Blue Coloration

Uranyl acetate has been used as an electron stain for en bloc staining as well as for staining ultrathin sections in conjunction with various lead stains (Fig. 1). Present studies reveal that various platinum compounds also show promise as electron stains. Certain platinum compounds have been shown to be effective anti-tumor agents. Of particular interest are the compounds with either uracil or thymine as one of the ligands (cis-Pt(II)-uracil; cis-Pt(II)-thymine). These compounds are amorphous, highly soluble in water and often exhibit an intense blue coloration. These compounds show enough electron density to be used as stains for electron microscopy. Most of the studies are based on various cell lines (human AV, cells, human lymphoma cells, KB cells, Sarcoma-180 ascites cells, chick fibroblasts and HeLa cells) while studies on tissue blocks are in progress.

Localization of immunolabels by electron microscopy and image averaging

1983 ◽  
Vol 41 ◽  
pp. 282-283
Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy
Keyword(s):  
Electron Microscopy ◽  
Single Particle ◽  
Attachment Site ◽  
Uranyl Acetate ◽  
Limulus Polyphemus ◽  
Resolution Limit ◽  
Electron Microscopic ◽  
Image Averaging ◽  
Top View ◽  
Better Than

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.

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