scholarly journals Surface properties related to concanavalin A-induced agglutination. A comparative study of several Entamoeba strains.

1977 ◽  
Vol 145 (3) ◽  
pp. 652-665 ◽  
Author(s):  
D Trissl ◽  
A Martínez-Palomo ◽  
C Argüello ◽  
M de la Torre ◽  
R de la Hoz
Keyword(s):  
Surface Properties ◽  
Concanavalin A ◽  
Room Temperature ◽  
Lectin Binding ◽  
Cationized Ferritin ◽  
Con A ◽  
Low Concentrations ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Axenic Strains

Pathogenic strains of Entamoeba histolytica are more easily agglutinated with concanavalin A (Con A) than strains isolated from human asymptomatic carriers. All three pathogenic strains studied here were found to agglutinate with low concentrations of Con A in contrast to various nonpathogenic axenic strains of amebas, characterized by their ability to grow at room temperature. Our present observations suggest that the extreme susceptibility of pathogenic strains of E. histolytica to agglutinate with Con A is related to their higher capacity for lectin binding and to their lack of detectable repulsive charges at the cell surface. The amount of fluorescein-tagged Con A bound to the surface was much higher in pathogenic strains. Only nonpathogenic strains showed a detectable negative surface charge as studied both by means of cell microelectrophoresis and by labeling cells with cationized ferritin at 0 degrees C. The mobility of surface Con A receptors estimated as the percentage of caps was comparable in all strains. Results of one strain cultured in axenic and monoxenic conditions suggested that bacteria can modify the behaviour of E. histolytica trophozoites by altering surface properties of the amebas.

Reduction of Surfactant Retention in Limestones Using Sodium Hydroxide

SPE Journal ◽  
2018 ◽  
Vol 24 (01) ◽  
pp. 92-115 ◽  
Author(s):  
D.. Wang ◽  
M.. Maubert ◽  
G. A. Pope ◽  
P. J. Liyanage ◽  
S. H. Jang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Sodium Hydroxide ◽  
Anionic Surfactants ◽  
Geochemical Modeling ◽  
Low Molecular Weight ◽  
Low Concentrations ◽  
Reservoir Conditions ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Indiana Limestone

Summary Geochemical modeling was used to design and conduct a series of alkaline/surfactant/polymer (ASP) coreflood experiments to measure the surfactant retention in limestone cores using sodium hydroxide (NaOH) as the alkali. Surfactant/polymer (SP) coreflood experiments were conducted under the same conditions for comparison. NaOH has been used for ASP floods of sandstones, but these are the first experiments to test it for ASP floods of limestones. Two studies performed under different reservoir conditions showed that NaOH significantly reduced the surfactant retention in Indiana Limestone. An ASP solution with 0.3 wt% NaOH has a pH of approximately 12.6 at 25°C. The high pH increases the negative surface charge of the carbonate, which favors lower adsorption of anionic surfactants. Another advantage of NaOH is that low concentrations of only approximately 0.3 wt% can be used because of its low molecular weight and its low consumption in limestones. Most reservoir carbonates contain gypsum or anhydrite, and therefore sodium carbonate (Na2CO3) will be consumed by the precipitation of calcium carbonate (CaCO3). As shown in the two studies, NaOH can be used in limestone reservoirs containing gypsum or anhydrite.

scholarly journals Distribution of concanavalin A binding sites on the surface of dissociated rat submandibular gland acinar cells.

1975 ◽  
Vol 23 (8) ◽  
pp. 607-617 ◽  
Author(s):  
T Amakawa ◽  
T Barka
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Surface ◽  
Concanavalin A ◽  
Binding Sites ◽  
Lectin Binding ◽  
Single Cells ◽  
Apical Cell ◽  
Acinar Cells ◽  
Con A ◽  
Dissociated Cells

The submandibular glands of 4-week-old rats were dissociated by a procedure involving digestions with collagenase and hyaluronidase, chelation of divalent cations and mechanical force. A suspension of single cells was obtained in low yield by centrifugation in a Ficoll-containing medium. Immediately after dissociation and after a culture period of 16-18 hr the dissociated cells were tested for agglutinability by concanavalin A (Con A). Using ferritin (tfer)-conjugated Con A the lectin binding by the isolated acinar cells was also studied. The dissociated cells were agglutinated by low concentrations of Con A and bound Fer-Con A molecules on their entire surface without any indication of polarization of the cell membrane. There was a considerable cell to cell variation in the amount of Fer-Con A binding which was, in general, sparse and patchy. The contact surfaces between agglutinated cells revealed a dense binding of Fer-Con A molecules irrespective of the types of cells participating in the agglutination reaction. Cells cultured for 16-18 hr were no longer agglutinated by Con A. As compared to the freshly dissociated cells the cultured acinar cells revealed a more uniform and denser binding of Fer-Con A molecules. Furthermore, there were more lectin molecules bound to the cell surface corresponding to the basal part of the cell, where the nucleus and most of the rough surface endoplasmic reticulum were located, than to the apical cell surface. It is suggested that the higher density of lectin-binding sites on the cell surface in the vicinity of the cisternae of the rough endoplasmic reticulum indicates insertion sites of newly synthesized membrane glycoproteins.

scholarly journals Schistosomula of Schistosoma mansoni clear concanavalin A from their surface by sloughing.

1982 ◽  
Vol 94 (2) ◽  
pp. 355-362 ◽  
Author(s):  
J C Samuelson ◽  
J P Caulfield ◽  
J R David
Keyword(s):  
Schistosoma Mansoni ◽  
Concanavalin A ◽  
Binding Sites ◽  
Culture Medium ◽  
Culture Media ◽  
Lectin Binding ◽  
Defined Medium ◽  
Con A ◽  
Sds Page ◽  
Lectin Binding Sites

The lectin concanavalin A (Con A) was used as a model probe to study the behavior of molecules bound to the surface of recently transformed schistosomula of Schistosoma mansoni. Con A binding was saturable (150-180 pg/organism) and specifically competed by alpha-methyl mannoside. Both FITC-Con A and 125-I-Con A were lost from the surface of schistosomula with a halftime of 8-10 h in culture in defined medium. A comparable decrease in the binding of Con A to schistosomula cultured and then labeled with the lectin indicated that the labeling procedure itself was not inducing the observed change. Internalization of Con A was not seen by either fluorescence microscopy or electron microscope radioautography. In addition, 70-80% of the radioactivity lost from the parasite was recoverable by TCA precipitation from the culture medium as intact Con A (27,000 mol wt on SDS PAGE). Thus, the mechanism of clearance of bound Con A from the surface of cultured schistosomula is apparently by sloughing of Con A molecules intact into the culture media and not by endocytosis and degradation. Con A binding sites, visualized with hemocyanin by scanning electron microscopy, appeared homogeneously distributed over the surface of schistosomula when organisms were labeled at 4 degree C or after fixation with glutaraldehyde. However, Con A and hemocyanin formed aggregates on the surface of schistosomula when labeling was performed at 37 degrees C, which suggests that lectin binding sites have lateral mobility within the plane of the membrane. These aggregates are likely independent of metabolism by the parasite because aggregation also occurs on the surface of organisms killed with azide.

Lectin Binding Demonstrates Different Glycoprotein Abnormalities In Thrombasthenic And Bernard-Soulier Platelets

1981 ◽  
Author(s):  
Philip A Judson ◽  
David J Anstee
Keyword(s):  
Arachis Hypogaea ◽  
Concanavalin A ◽  
Marked Reduction ◽  
Human Platelet ◽  
Lectin Binding ◽  
Minor Components ◽  
Polyacrylamide Gels ◽  
Con A ◽  
Platelet Membranes ◽  
Bernard Soulier Syndrome

We have previously shown that the lectins from Maclura aurantiaca (Ma) and Arachis hypogaea (Ah) (peanut) bind selectively to GP-I in human platelet membranes. In contrast Concanavalin A lectin binds primarily to GP-III. GP-I is deficient or absent from the membranes of individuals with Bernard-Soulier Syndrome (B-S.S.) while GP-II and III are deficient or absent from Thrombasthenic (G.T.) platelets. We have investigated the binding of radioiodinated lectins to SDS polyacrylamide gels of whole platelets from patients with B-S.S. and G.T. The object of this study was to define further the nature of the glycoprotein abnormalities in these conditions.The results clearly demonstrated a marked reduction in the binding of Ma and Ah lectins to the GP-I region of B-S platelets when compared to that of normal platelets. No new lectin binding components were observed. The binding of Con A lectins to B-S platelets did not appear to be significantly different from that to normal platelets. In contrast Ma and Ah binding to G.T. platelets appeared normal whereas the binding of Con A to GP-III was markedly reduced. Two faint Con A binding bands were apparent in the GP-III region of the G.T. platelets. It is not clear whether either of these represent residual GP-III or if they are minor components masked by GP-III in normal platelets. The carbohydrate of GP-I in normal platelets consists almost entirely of O-glycosidically linked oligosaccharides. Ah and Ma lectins bind selectively to galactosyl and N-acetylgalactosaminyl residues in this type of oligosaccharide. We conclude that B-S platelets have a gross deficiency of O-glycosidically linked oligosaccharides. Con A binds selectively to branched N-glycosidically linked oligosaccharides with a mannose-rich core. We conclude that such structures normally present on GP-III are grossly deficient in G.T. platelets.

Ferritin-Conjugated Plant Agglutinins as Specific Stains for Cell Surface Saccharides

1971 ◽  
Vol 29 ◽  
pp. 536-537
Author(s):  
G. L. Nicolson ◽  
S. J. Singer
Keyword(s):  
Cell Surface ◽  
Concanavalin A ◽  
Room Temperature ◽  
Ultrastructural Localization ◽  
Final Concentration ◽  
Alkaline Ph ◽  
Con A ◽  
Specific Sugar

Plant agglutinins are proteins which bind to specific sugar ligands. For the ultrastructural localization of specific saccharides, we have now conjugated two different plant agglutinins with ferritin (Fer): concanavalin A (Con A), which binds specifically to sugars sterically related to D-glucose and D-mannose, and ricin (Ric), specific for sugars related to D-galactose and L-rhamnose.The conjugates Fer-Con A and Fer-Ric are prepared as follows. To a solution containing 8% Fer and 2.5% purified agglutinin in a buffer (SPB) containing 0.5M NaCl, 0.05M Na phosphate, pH 6.8, is added with stirring freshly distilled glutaraldehyde to a final concentration of 0.05%. Alkaline pH must be avoided to prevent aggregation of the agglutinins. After 45 min. at room temperature the mixture is dialyzed against SPB containing 0.1M NH4Cl. The Fer-agglutinins are centrifuged to remove large aggregates and finally chromatographically purified on Agarose A-1.5m (Fer-ConA) or Biogel P300 (Fer-Ric).

Surface charge of insect haemocytes, examined using cell electrophoresis and cationized ferritin-binding

1985 ◽  
Vol 75 (1) ◽  
pp. 207-214
Author(s):  
G. Takle ◽  
A.M. Lackie
Keyword(s):  
Surface Charge ◽  
Periplaneta Americana ◽  
Schistocerca Gregaria ◽  
Cationized Ferritin ◽  
Cell Electrophoresis ◽  
Insect Haemocytes ◽  
Negative Surface ◽  
Negative Surface Charge

Differences in the negative surface charge of haemocytes from Periplaneta americana and Schistocerca gregaria have been revealed using cell electrophoresis and cationized ferritin-binding. Although haemocyte populations from both insect species exhibit ranges of negative surface charge, both techniques show that Schistocerca haemocytes are significantly more negative than Periplaneta haemocytes. The results may help to explain why Schistocerca haemocytes adhere poorly to negative substrata, both in vitro and in vivo, and suggest that an electrostatic mechanism may be involved, at least in part, in adhesion of insect haemocytes to substrata.

Electrophoretic mobility of microsomes from rat liver

1977 ◽  
Vol 23 (1) ◽  
pp. 285-297
Author(s):  
D. Blad ◽  
L. Winqvist ◽  
G. Dallner
Keyword(s):  
Electrophoretic Mobility ◽  
Liver Microsomes ◽  
Protein Species ◽  
Electrophoretic Mobilities ◽  
Low Concentrations ◽  
Structural Differences ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
And Control ◽  
Phosphate Groups

The electrophoretic mobilities of rough and smooth microsomes were studied using free electrophoresis in a sucrose gradient. Rough microsomes have a higher net negative surface charge but removal of the ribosomes decreases their mobility to that of smooth microsomes. Treatment with neuraminidase and phospholipases C and D does not affect the mobility of total smooth microsomes, but this mobility is increased by approximately 20% after trypsin and papain treatment and by approximately 12% after phospholipase A treatment. Further treatment of trypsin-digested smooth microsomes with phospholipase C re-establishes the original mobility. This effect is not caused by the removal of lipid phosphate groups, but by the liberation of negatively charged protein species that are normally buried under trypsin-sensitive proteins. Low concentrations of trypsin also solubilize enzyme proteins from smooth liver microsomes of phenobarbital-treated rats, but the electrophoretic mobility is not increased, indicating structural differences between induced and control membranes.

scholarly journals Removal of Cadmium from Aqueous Solutions by Saccharomyces cerevisiae–Alginate System

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4128
Author(s):  
Silvia Carolina Moreno Rivas ◽  
Rosa Idalia Armenta Corral ◽  
María del Carmen Frasquillo Félix ◽  
Alma Rosa Islas Rubio ◽  
Luz Vázquez Moreno ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fixed Bed ◽  
Alginate Beads ◽  
Fixed Bed Column ◽  
Removal Capacity ◽  
Column System ◽  
Low Concentrations ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Efficient Option

The aim of this study was to determine the Cd2+ removal capacity of a biosorbent system formed by Saccharomyces cerevisiae in calcium alginate beads. The adsorption of Cd2+ by a S. cerevisiae–alginate system was tested either by batch or fixed-bed column experiments. The S. cerevisiae–alginate system was characterized using dynamic light scattering (DLS, zeta potential), size, hardness, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy. Beads of the S. cerevisiae–alginate system showed a spherical–elliptical morphology, diameter of 1.62 ± 0.02 mm, 96% moisture, negative surface charge (−29.3 ± 2.57 mV), and texture stability during storage at 4 °C for 20 days. In batch conditions, the system adsorbed 4.3 µg of Cd2+/g of yeast–alginate beads, using a Cd2+ initial concentration of 5 mg/L. Adsorption capacity increased to 15.4 µg/g in a fixed-bed column system, removing 83% of total Cd2+. In conclusion, the yeast–alginate system is an efficient option for the removal of cadmium at low concentrations in drinking water.

Lack of binding of serum glycoprotein hormone α subunit to Concanavalin A–Sepharose reflects increased branching of the oligosaccharide chains

1984 ◽  
Vol 103 (1) ◽  
pp. 111-116 ◽  
Author(s):  
A. J. Chapman ◽  
J. T. Gallagher ◽  
C. G. Beardwell ◽  
S. M. Shalet
Keyword(s):  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Ricinus Communis ◽  
Lectin Binding ◽  
Pituitary Tumours ◽  
Con A ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
Binding Forms

ABSTRACT The lectin-binding properties of serum α subunit were studied by lectin affinity chromatography. Normal individuals and most patients with pituitary tumours produced α subunit which bound specifically to Concanavalin A–Sepharose (Con A). Some patients with pituitary tumours produced both Con A-reactive α subunit and α subunit which did not bind to Con A. Concanavalin A–Sepharose-binding α subunit from all sources bound strongly to Ricinus communis agglutinin–Sepharose after treatment with neuraminidase. Serum α subunit from those patients with pituitary tumours, which did not bind to Con A, bound to wheat germ agglutinin–Sepharose, exhibiting both weakly binding and strongly binding forms. Serum α subunit from both patients and controls, which did bind to Con A, showed only weak affinity for wheat germ agglutinin–Sepharose. Neither the low affinity nor the high affinity of serum α subunit from any source for wheat germ agglutinin–Sepharose was affected by neuraminidase. These findings show that (a) the predominant pattern of glycosylation of serum α subunit from normal controls is a Con A-reactive, biantennate complex oligosaccharide and (b) that the structural alteration which results in serum α subunit which does not bind to Con A in some patients with pituitary tumours is not an absence of carbohydrate, rather the α subunit contains highly branched, either complex or hybrid oligosaccharides. J. Endocr. (1984) 103, 111–116

scholarly journals Effects of Chitosan onCandida albicans: Conditions for Its Antifungal Activity

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Antonio Peña ◽  
Norma Silvia Sánchez ◽  
Martha Calahorra
Keyword(s):  
Yeast Cells ◽  
Low Molecular Weight ◽  
Extracellular Acidification ◽  
Pathogenic Yeast ◽  
Inhibition Of Growth ◽  
Low Concentrations ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
High Concentrations ◽  
Transmembrane Potential Difference

The effects of low molecular weight (96.5 KDa) chitosan on the pathogenic yeastCandida albicanswere studied. Low concentrations of chitosan, around 2.5 to 10 μg·mL−1produced (a) an efflux of K+and stimulation of extracellular acidification, (b) an inhibition of Rb+uptake, (c) an increased transmembrane potential difference of the cells, and (d) an increased uptake of Ca2+. It is proposed that these effects are due to a decrease of the negative surface charge of the cells resulting from a strong binding of the polymer to the cells. At higher concentrations, besides the efflux of K+, it produced (a) a large efflux of phosphates and material absorbing at 260 nm, (b) a decreased uptake of Ca2+, (c) an inhibition of fermentation and respiration, and (d) the inhibition of growth. The effects depend on the medium used and the amount of cells, but in YPD high concentrations close to 1 mg·mL−1are required to produce the disruption of the cell membrane, the efflux of protein, and the growth inhibition. Besides the findings at low chitosan concentrations, this work provides an insight of the conditions required for chitosan to act as a fungistatic or antifungal and proposes a method for the permeabilization of yeast cells.

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