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.

Assessment of Damage to Human Platelets after Aggregation and Other Injuries by Microscopic Observation and Estimation of Serotonin Uptake

1970 ◽  
Vol 23 (02) ◽  
pp. 261-275 ◽  
Author(s):  
G Zbinden ◽  
J. N Mehrishi ◽  
S Tomlin
Keyword(s):  
Platelet Aggregation ◽  
Electrophoretic Mobility ◽  
Human Platelets ◽  
Freezing And Thawing ◽  
Low Degree ◽  
Microscopic Evaluation ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Charged Macromolecules ◽  
5 Ht Uptake

SummaryThe severity of platelet damage induced by hyper- and hypotonic NaCl solutions and freezing and thawing was assessed by microscopic evaluation and measuring inhibition of 5-HT uptake. The same techniques were used to quantitate the effects of aggregating agents. The positively charged macromolecules PS, Poly-L und Poly-O reduced the net negative surface charge as determined by microelectrophoresis, caused platelet aggregation and inhibited 5-HT uptake. The damaging effects of Poly-L and Poly-O were more severe and more closely related to concentration than that of PS. The negatively charged macromolecules Poly-IC and NaPS increased the anodic electrophoretic mobility. Poly-IC and heparin caused a low degree of platelet clumping and no inhibition of 5-HT uptake. NaPS produced severe platelet damage with extensive clumping and complete inhibition of 5-HT uptake. Na laurate had the same effect, but did not alter electrophoretic mobility. ADP caused concentration-dependent platelet aggregation and inhibition of 5-HT uptake. The effects of ADP and NaPS were compared in agitated and non-agitated platelet samples containing identical concentrations of the 2 compounds. Agitation was found to increase the degree of platelet clumping and to reduce 5-HT uptake.

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 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.

scholarly journals The surface charge of trypanosomatids

2002 ◽  
Vol 74 (4) ◽  
pp. 649-675 ◽  
Author(s):  
THAÏS SOUTO-PADRÓN
Keyword(s):  
Surface Charge ◽  
Developmental Stages ◽  
Sialic Acids ◽  
Charged Surface ◽  
Direct Measurements ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Species Specific ◽  
Phosphate Groups ◽  
Electrophoretic Mobility Of Cells

The surface charge of trypanosomatids was evaluated by means of the binding of cationic particles, as visualized by electron microscopy and by direct measurements of the electrophoretic mobility of cells. The results obtained indicate that most of the trypanosomatids exhibit a negatively charged surface whose value is species specific and varies according to the developmental stages. Sialic acids associated with glycoproteins, glycolipids and phosphate groups are the major components responsible for the net negative surface charge of the trypanosomatids.

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.

scholarly journals Morphomolecular Characterization of Serum Nanovesicles From Microbiomes Differentiates Stable and Infarcted Atherosclerotic Patients

2021 ◽  
Vol 8 ◽  
Author(s):  
Camila Rodrigues Moreno ◽  
José Antonio Franchini Ramires ◽  
Paulo Andrade Lotufo ◽  
Alexandre Matos Soeiro ◽  
Luanda Mara da Silva Oliveira ◽  
...  
Keyword(s):  
Prognostic Biomarker ◽  
Plaque Rupture ◽  
Oxygen Species ◽  
Important Complication ◽  
Patients With Heart Failure ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Artery Disease ◽  
And Control

Microbial communities are considered decisive for maintaining a healthy situation or for determining diseases. Acute myocardial infarction (AMI) is an important complication of atherosclerosis caused by the rupture of atheroma plaques containing proinflammatory cytokines, reactive oxygen species, oxidized low-density lipoproteins (oxLDL), damaged proteins, lipids, and DNA, a microenvironment compatible with a pathogenic microbial community. Previously, we found that archaeal DNA-positive infectious microvesicles (iMVs) were detected in vulnerable plaques and in the sera of Chagas disease patients with heart failure. Now, we characterize and quantify the levels of serum microbiome extracellular vesicles through their size and content using morphomolecular techniques to differentiate clinical outcomes in coronary artery disease (CAD). We detected increased numbers of large iMVs (0.8–1.34 nm) with highly negative surface charge that were positive for archaeal DNA, Mycoplasma pneumoniae antigens and MMP9 in the sera of severe AMI patients, strongly favoring our hypothesis that pathogenic archaea may play a role in the worst outcomes of atherosclerosis. The highest numbers of EVs <100 nm (exosomes) and MVs from 100 to 200 nm in the stable atherosclerotic and control healthy groups compared with the AMI groups were indicative that these EVs are protective, entrapping and degrading infectious antigens and active MMP9 and protect against the development of plaque rupture.Conclusion: A microbiome with pathogenic archaea is associated with high numbers of serum iMVs in AMI with the worst prognosis. This pioneering work demonstrates that the morphomolecular characterization and quantification of iEVs in serum may constitute a promising serum prognostic biomarker in CAD.

Platelet Surface Charge and Aggregation Effects of Polyelectrolytes

1969 ◽  
Vol 21 (03) ◽  
pp. 450-462 ◽  
Author(s):  
K. A Gröttum
Keyword(s):  
Platelet Aggregation ◽  
Surface Charge ◽  
Electrophoretic Mobility ◽  
Calcium Ions ◽  
Platelet Rich Plasma ◽  
Dextran Sulphate ◽  
Platelet Surface ◽  
Normal Platelet ◽  
Negative Surface ◽  
Negative Surface Charge

SummaryThe effect on platelet surface charge by adding the polybases : Dextran-DEAE and Polybrene and the polyacids : Dextran sulphate, heparin and bovine platelet fibrinogen to platelet-rich plasma was studied by platelet electrophoresis. In small concentrations all the reagents decreased the electrophoretic mobility of platelets, but not that of erythrocytes, suggesting that the polymeric agents were specifically adsorbed to the platelets and thereby reducing their negative surface charge. When the reagents reduced the electrophoretic mobility of the platelets to 85% of normal, platelet aggregation was induced. This effect was probably not mediated through release of ADP, as the presence of ADPase did not modify the effect. The influence of polybases was not inhibited by EDTA. The effect of Dextran sulphate was inhibited by EDTA and increased by small amounts of calcium ions. Increasing concentrations of Dextran sulphate and heparin increased the electrophoretic mobility of platelets, but did not aggregate the platelets. The results suggest that a decrease in the platelet electrostatic potential is essential in platelet aggregation.

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.

Device for the detection of short trace gas pulses

2018 ◽  
Vol 85 (7-8) ◽  
pp. 496-503 ◽  
Author(s):  
Tobias Baur ◽  
Caroline Schultealbert ◽  
Andreas Schütze ◽  
Tilman Sauerwald
Keyword(s):  
Surface States ◽  
High Sensitivity ◽  
Oxide Semiconductor ◽  
Temperature Modulation ◽  
Surface Charges ◽  
Low Concentrations ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Reducing Gases ◽  
Accurate Temperature Control

Abstract A device for detection of short gas pulses at very low concentrations is presented. The approach is based on a special temperature modulation technique enabling a differential surface reduction (DSR) measurement of a metal oxide semiconductor (MOS) gas sensor. With this method, the sensor surface is highly covered with oxidized surface states at high temperature (e. g. 400 °C) initially. The temperature is then reduced abruptly to, e. g., 100 °C resulting in a state with strong excess of negative surface charge. Reactions of these surface charges with reducing gases are prevailing and lead to very high sensitivity. For the measurement a dedicated detector (electronics and fluidic system) is presented. The electronics allows a high-resolution conductance measurement of the sensitive layer and accurate temperature control. The fluidic system is examined in terms of peak shape and optimal sensor response via FEM simulations.

Surface charge and extracellular polymer of sludge in the anaerobic degradation process

1996 ◽  
Vol 34 (5-6) ◽  
pp. 309-316 ◽  
Author(s):  
X. S. Jia ◽  
Herbert H. P. Fang ◽  
H. Furumai
Keyword(s):  
Surface Charge ◽  
Growth Phase ◽  
Anaerobic Degradation ◽  
Degradation Process ◽  
Anaerobic Sludge ◽  
Batch Experiments ◽  
High Substrate Concentration ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Extracellular Polymer

Changes of surface charge and extracellular polymer (ECP) content were investigated in batch experiments for three anaerobic sludges, each of which had been enriched at 35°C and pH 639-7.3 for more than 40 batches using propionate, butyrate and glucose, individually, as the sole substrate. Results showed that both ECP and the negative surface charge were dependent on the growth phase of microorganisms. They increased at the beginning of all batches when the microorganisms were in the prolific-growth phase, having high substrate concentration and food-to-microorganisms ratio. Both later gradually returned to their initial levels when the microorganisms were in the declined-growth phase, as the substrate became depleted. The negative surface charge increased linearly with the total-ECP content in all series with slopes of 0.0187, 0.0212 and 0.0157 meq/mg-total-ECP for sludge degrading propionate, butyrate and glucose, respectively. The change of surface charge for the first two sludges was mainly due to the increase of proteinaceous fraction of ECP; but, for glucose-degrading sludge, that could be due to the increases of both proteinaceous and carbohydrate fractions of ECP. The negative-charged nature of anaerobic sludge implies that cations should be able to promote granulation of anaerobic sludge.

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