scholarly journals Thermodynamic, Kinetic, and Electron Microscopy Studies of Concanavalin A and Dioclea grandiflora Lectin Cross-linked with Synthetic Divalent Carbohydrates

2005 ◽  
Vol 280 (10) ◽  
pp. 8640-8646 ◽  
Author(s):  
Tarun K. Dam ◽  
Stefan Oscarson ◽  
René Roy ◽  
Sanjoy K. Das ◽  
Daniel Pagé ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Concanavalin A ◽  
Dioclea Grandiflora

Adhesion of Phytophthora palmivora zoospores: detection and ultrastructural visualization of concanavalin A-receptor sites appearing during encystment

1975 ◽  
Vol 19 (1) ◽  
pp. 11-20
Author(s):  
V.O. Sing ◽  
S. Bartnicki-Garcia
Keyword(s):  
Electron Microscopy ◽  
Cell Surface ◽  
Concanavalin A ◽  
Solid Surfaces ◽  
Trypsin Digestion ◽  
Phytophthora Palmivora ◽  
Con A ◽  
Binding Material ◽  
Ultraviolet Microscopy ◽  
Receptor Sites

The binding of concanavalin A (Con A) to the cell surface of zoospores and cysts of Phytophthora palmivora was studied by radiometry (125I-Con A), ultraviolet microscopy (fluorescein-Con A) and electron microscopy peroxidase-diaminobenzidine technique). Zoospores were found to secrete during the early stages of encystment a Con A-binding material susceptible to trypsin digestion. This glycoprotein is contained in the so-called peripheral vesicles and is probably responsible for the adhesion of the encysting zoospores to solid surfaces.

scholarly journals Nonuniform distribution of concanavalin-A receptors and surface antigens on uropod-forming thymocytes.

1978 ◽  
Vol 79 (1) ◽  
pp. 235-251 ◽  
Author(s):  
S de Petris
Keyword(s):  
Electron Microscopy ◽  
Normal Distribution ◽  
Concanavalin A ◽  
Cytochalasin B ◽  
Surface Antigens ◽  
Nonuniform Distribution ◽  
Inhomogeneous Distribution ◽  
Spherical Cells ◽  
Concanavalin A Receptors

Uropods can form spontaneously in a variable fraction of mouse thymocytes incubated for 30--60 min in vitro at temperatures between about 8 degrees and 37 degrees C. The majority of the cells with a typical uropod are medium and large thymocytes. The "normal" distribution of concanavalin-A receptors and antigens recognized by a rabbit anti-mouse thymocyte serum was studied on these cells by electron microscopy using ferritin-conjugated lectin or antibodies. The cells were fixed with glutaraldehyde or formaldehyde before labeling. The distribution was essentially uniform on spherical cells. On the contrary, on cells which had formed a uropod the labeled receptors and antigens appeared to be preferentially concentrated around the nucleus, and depleted over the uropod, and especially over the constriction at the base of the uropod. Uropod formation and inhomogeneous distribution were inhibited or reversed by cytochalasin B, but not by vinblastine or colchicine. When the same ligands were applied to unfixed cells, the labeled and cross-linked components capped normally towards the cytoplasmic pole of the cell. These observations are described in relation to the ability of receptors and antigens to interact with an intracellular mechanical structure, and to the mechanism of capping.

scholarly journals Concanavalin A-Induced Morphological Changes and Its Binding Sites in Starfish Follicle Cells as Revealed by Electron Microscopy

1981 ◽  
Vol 23 (2) ◽  
pp. 111-123 ◽  
Author(s):  
NORIO KAWAI ◽  
KIYOSHI SANO ◽  
YOSHITAKA NAGAHAMA ◽  
HARUO KANATANI ◽  
HIROSHI HIRANO
Keyword(s):  
Electron Microscopy ◽  
Concanavalin A ◽  
Binding Sites ◽  
Morphological Changes ◽  
Follicle Cells

scholarly journals Localization of concanavalin A binding carbohydrate in Chlamydomonas flagella

1984 ◽  
Vol 68 (1) ◽  
pp. 211-226
Author(s):  
B.E. Millikin ◽  
R.L. Weiss
Keyword(s):  
Electron Microscopy ◽  
Concanavalin A ◽  
Fluorescein Isothiocyanate ◽  
Surface Coat ◽  
Subsurface Zone ◽  
Flagellar Membrane

Chlamydomonas flagella are shown to possess two zones of concanavalin A (ConA) binding carbohydrate. The first zone, distinguished by a requirement for a prolonged labelling period for visualization of fluorescein isothiocyanate (FITC)-ConA fluorescence, is localized in the flagellar coat. The second zone is characterized by a rapid FITC- and [125I]ConA labelling subsequent to disruption of the flagellar membrane, but is unaffected by reagents that act only on the flagellar surface coat. Electron microscopy and ferritin-ConA labelling indicate that this subsurface zone is localized between the flagellar membrane and axoneme in the space that we term the flagelloplasm. These results are used to suggest possible functions for ConA binding glycosyl residues in flagella.

Surface structure of the golgi complex and identification of concanavalin-A binding sites

1978 ◽  
Vol 36 (2) ◽  
pp. 246-247
Author(s):  
J.M. Sturgess ◽  
M. Teitelman ◽  
M.A. Moscarello
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Golgi Complex ◽  
Concanavalin A ◽  
Binding Sites ◽  
Lectin Binding ◽  
Bicarbonate Buffer ◽  
Sodium Phosphate Buffer ◽  
Scanning Electron ◽  
Lectin Binding Sites

Scanning electron microscopy has been applied to study the surface ultrastructure of the Golgi complex and labelling techniques have been developed to investigate the distribution of lectin-binding sites on the membrane surfaces. The study is based on the examination of Golgi-rich fractions, isolated by homogenisation and differential centrifugation of rat liver. The membranes are fixed in suspension with 1% glutaraldehyde in 0.1 M sodium phosphate buffer, pH 7.4 for 60 mins and then rinsed in distilled water. For scanning electron microscopy, a thin film of membrane is frozen rapidly on coverglasses using liquid Freon 22, cooled by liquid nitrogen and dried in vacuo at -60°C. Membranes are coated with approximately 100 Å gold in a sputter coater and examined at 20 kV in a JEOL JSM-35U scanning electron microscope. For transmission electron microscopy, membranes are processed as described previously. For examination of lectin binding sites, isolated Golgi membranes are washed in sodium bicarbonate buffer, fixed in glutaraldehyde, incubated with concanavalin A (Con A), rinsed in buffer and then incubated with hemocyanin1.

scholarly journals Distribution of receptor sites on large glycoprotein molecules by electron microscopy. Application to epiglycanin

1981 ◽  
Vol 193 (1) ◽  
pp. 203-207 ◽  
Author(s):  
H S Slayter ◽  
J F Codington
Keyword(s):  
Electron Microscopy ◽  
Concanavalin A ◽  
Active Sites ◽  
Ricinus Communis ◽  
Tumour Cells ◽  
Mammary Tumour ◽  
New Approach ◽  
Extended Conformation ◽  
Receptor Sites ◽  
Carbohydrate Chains

Electron microscopy was used to map the loci of immunochemically active sites on individual glycoprotein molecules. The positions of specific galactose residues and asparagine-linked carbohydrate chains containing specific mannose residues in epiglycanin, a glycoprotein of extended conformation from the surface of TA3 mouse mammary tumour cells, were observed in complexes with Ricinus communis toxin and concanavalin A respectively. The maximum number of Ricinus communis toxin molecules attached to a single epiglycanin molecule was 23, and the average number was 16. Only one concanavalin A molecule was observed attached to any epiglycanin molecule, and this at one end of the molecule, suggesting the presence of only one receptor for this lectin. By means of this new approach for mapping specific residues, evidence has been obtained that suggests microheterogeneity in epiglycanin with respect to the locations of carbohydrate chains containing receptors for Ricinus communis toxin.

scholarly journals Developmental reorganization of the skeletal framework and its surface lamina in fusing muscle cells.

1981 ◽  
Vol 91 (1) ◽  
pp. 103-112 ◽  
Author(s):  
A B Fulton ◽  
J Prives ◽  
S R Farmer ◽  
S Penman
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Concanavalin A ◽  
Muscle Cells ◽  
Surface Proteins ◽  
Transmission Electron ◽  
Continuous Surface ◽  
Internal Networks ◽  
Structural Networks ◽  
Whole Mounts

The skeletal framework of cells, composed of internal structural fibers, microtrabeculae, and the surface lamina, is revealed with great clarity after extraction with detergent. When muscle cells fuse to form a multinucleated myotube, their skeletal framework reorganizes extensively. When myoblasts prepare to fuse, the previously continuous surface lamina develops numerous lacunae unique to this stage. The retention of iodinated surface proteins suggests that the lacunae are not formed by the extraction of lamina proteins. The lacunae appear to correspond to extensive patches that do not bind concanavalin A and are probably regions of lipid bilayer devoid of glycoproteins. The lacunae appear to be related to fusion and disappear rapidly after the multinucleated myotube is formed. When muscle cells fuse, their internal structural networks must interconnect to form the framework of the myotube. Transmission electron microscopy of skeletal framework whole mounts shows that proliferating myoblasts have well developed and highly interconnected internal networks. Immediately before fusion, these networks are extensively reorganized and destabilized. After fusion, a stable, extensively cross-linked internal structure is reformed, but with a morphology characteristic of the myotube. Muscle cells therefore undergo extensive reorganization both on the surface and internally at the time of fusion.

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