Carbohydrate recognition systems in avian sinusoidal liver cells

1990 ◽  
Vol 10 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Luciana Dini ◽  
Palma Mattioli
Keyword(s):  
Cell Surface ◽  
Binding Sites ◽  
Specific Binding ◽  
Adult Life ◽  
Liver Cells ◽  
Carbohydrate Recognition ◽  
Adult Chicken ◽  
Specific Binding Sites ◽  
Recognition Systems ◽  
Sinusoidal Liver Cells

We studied the carbohydrate recognition systems on liver sinusoidal cells of adult chicken and 20-day-old embryos. We localized and quantified the binding sites for glycoproteins exposing terminal N-acetylglucosamine (GlcNAc), mannose and galactose (Gal) residues. Sinusoidal liver cells from animals of both ages express on their cell surfaces binding sites for GlcNAc, mannose and galactose residues, while hepatocytes bind glycoproteins with GlcNAc resiudes. The gold particles distribution on Kuffer cells depend on the binding sites and the age considered. Binding sites for GlcNAc and Gal residues are generally present as clusters of gold granules, while mannose-specific binding sites are always as single gold granules. Ligand-gold complexes bound on endothelial cells are always present on the coated regions of the cell surface. The number of GlcNAc and Gal-specific receptors expressed on the cell surface of Kupffer cells undergoes modifications between embryonal and adult life.

Chick hepatic lectins: An electron microscopic study on isolated hepatocytes during development

1991 ◽  
Vol 11 (5) ◽  
pp. 257-264
Author(s):  
L. Falasca ◽  
P. Mattioli ◽  
L. Dini
Keyword(s):  
Binding Sites ◽  
Specific Binding ◽  
Ultrastructural Level ◽  
Isolated Hepatocytes ◽  
Cell Surfaces ◽  
Electron Microscopic ◽  
Specific Binding Sites ◽  
Neonatal Life ◽  
Specific Receptors ◽  
Recognition Systems

We studied the carbohydrate recognition systems of hepatocytes isolated from 16-day-old embryos, 19-day-old embryos and chicks within 24 h of hatching. We localized and quantified at the ultrastructural level the binding sites for glycoproteins exposing terminal N-acetylglucosamine (GlcNAc), mannose and N-acetylgalactosamine (GalNAc) residues by means of protein-gold complexes. Binding sites specific for GlcNAc and mannose residues are present on hepatocytes from embryos and chicks. On the contrary GalNAc specific binding sites are exclusively observed on cells from 16-day-old embryos. The number and distribution of gold particles on hepatocyte cell surfaces depend on the binding sites and the age considered. We describe a modulation in the number of GlcNAc, and mannose specific receptors present on the cell surface between the embryonal stage and neonatal life.

Specific rosette formation between fibroblasts and erythrocytes

1981 ◽  
Vol 51 (1) ◽  
pp. 279-294
Author(s):  
S.D. Rosen ◽  
M.S. Singer ◽  
C.G. Glabe ◽  
L.B. Grabel
Keyword(s):  
Cell Surface ◽  
Binding Sites ◽  
Specific Binding ◽  
Rosette Formation ◽  
Dependent Manner ◽  
Erythrocyte Ghosts ◽  
Bhk Cells ◽  
Specific Binding Sites ◽  
Protease Treatment ◽  
Specificity Of Binding

Fibroblast cells (BHK-21, Swiss 3T3, SV403T3, L929) will form rosettes by binding to erythrocytes of specific types. The specificity of binding varies with the cell line. Monolayer cultures of spread baby hamster kidney (BHK) cells also bind erythrocytes with the same specificity exhibited by suspended cells. Our studies have concentrated on rosette formation between trypsinzed-ox (TOx) erythrocytes and BHK cells. Extensive protease treatment of the BHK cells reduces their ability to bind TOx erythrocytes in a dose- and time-dependent manner, suggesting the involvement of protein in the binding site. Simple saccharides, and glycopeptide isolated from ox erythrocyte ghosts, do not inhibit rosetting. However, neutral glycosphinogolipids from ox erythrocyte ghosts inhibit BHK-TOx rosetting, whereas neutral glycosphingolipids from non-rosetting rabbit erythrocytes have no effect on rosetting. Furthermore, incorporation of ox glycolipids into guinea-pig erythrocytes causes these non-rosetting erythrocytes to adhere to BHK cells. These experiments suggest that specific glycolipids of the ox erythrocyte act as receptors for binding sites on the cell surface of BHK cells. These cell-specific binding sites may play a role in cell-surface events involving carbohydrate recognition.

scholarly journals Specific Binding of Rubidium in Chlorella

1962 ◽  
Vol 45 (5) ◽  
pp. 959-977 ◽  
Author(s):  
Dan Cohen
Keyword(s):  
Active Transport ◽  
Binding Sites ◽  
Specific Binding ◽  
High Concentration ◽  
External Concentration ◽  
Specific Binding Sites ◽  
Dense Suspension ◽  
Concentration Of Ions ◽  
The Individual ◽  
A Site

Specific binding sites for potassium, which may be components of the carriers for active transport for K in Chlorella, were characterized by their capacity to bind rubidium. A dense suspension was allowed to take up Rb86 from a low concentration of Rb86 and a high concentration of ions which saturate non-specific sites. The amount bound was derived from the increase in the external concentration of Rb86 following addition of excess potassium. The sites were heterogeneous. The average affinity of Rb and various other ions for the sites was determined by plotting the degree of displacement of Rb86 against log molar concentration of the individual ions. Interpolation gave the concentration for 50 per cent displacement of Rb, which is inversely related to affinity. The order of affinity was not changed when the cells were frozen, or boiled either in water or in 70 per cent ethanol. The affinity is maximal for ions with a crystalline radius of 1.3 to 1.5 A and a high polarizability, and is not related to the hydrated radius or valency. It is suggested that binding groups in a site are rigidly arranged, the irregular space between them being 2.6 to 3.0 A across, so that affinity is high for ions of this diameter and high polarizability.

Studies of the uptake of macromolecules by cells. I. Uptake of proteins by cells of the Ehrlich–Lettré ascites carcinoma

1968 ◽  
Vol 46 (12) ◽  
pp. 1443-1450 ◽  
Author(s):  
Y. C. Choi ◽  
E. R. M. Kay
Keyword(s):  
Nucleic Acid ◽  
Cell Membrane ◽  
Binding Sites ◽  
Specific Binding ◽  
Protein Uptake ◽  
Specific Binding Sites ◽  
Model Protein ◽  
Uptake Process ◽  
Kinetics Of ◽  
Protein Treatment

The uptake of protein by cells of the Ehrlich–Lettré ascites carcinoma was characterized kinetically by using hemoglobin as a model protein. An attempt was made to show that the process is not an artefact due to nonspecific adsorption of protein to the cell membrane. The kinetics of the uptake process suggested that an interaction exists between the exogenous protein and specific binding sites on the membrane. Acetylation of hemoglobin enhanced the rate of uptake of this protein. Treatment of cells with neuraminidase, phospholipase A, and Pronase resulted in an inhibition of protein uptake. The experimental evidence for the uptake of hemoglobin was supported by evidence that L-serine-U-14C-labelled hemoglobin is transported into the cytoplasm and utilized subsequently, resulting in labelling of the nucleic acid nucleotides.

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