The Negative Surface Charge Density of Cells and Their Actual State of Differentiation or Activation

2020 ◽  
pp. 267-280
Author(s):  
Johann Bauer
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Actual State ◽  
Negative Surface ◽  
Negative Surface Charge

scholarly journals Alteration of the Cell Periphery During Granulocyte Maturation: Relationship to Cell Function

Blood ◽  
1972 ◽  
Vol 39 (3) ◽  
pp. 301-316 ◽  
Author(s):  
Marshall A. Lichtman ◽  
Robert I. Weed
Keyword(s):  
Bone Marrow ◽  
Charge Density ◽  
Surface Charge ◽  
Functional Capacity ◽  
Surface Charge Density ◽  
Cell Spreading ◽  
Cell Periphery ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Immature Granulocyte

Abstract Physiologic characteristics of the surface of human granulocytes may be important determinants of functional capacity. Studies of immature granulocytes and polymorphonuclear neutrophils (PMN’s) from marrow and blood indicated that immature granulocytes are characterized by a high, neuraminidase-susceptible, negative surface charge density; a high degree of cellular rigidity, as measured by an elastimeter with a micropipette orifice size that approximated estimates of average bone marrow basement membrane pore size (3.5µ); low adhesiveness to glass and plastic; low propensity to aggregate; a slow rate of cell spreading, pseudopod extension, and motility; and a very low rate of phagocytosis. At the myelocyte stage, adhesiveness and phagocytosis, although not prominent, became evident. In contrast PMN’s had a lower negative surface charge density, a higher degree of surface deformability (the entire PMN readily deforming to enter a 3.5µ micropipette whereas the immature granulocyte would not so deform), higher adhesiveness (plastic > glass), a higher propensity to aggregate, a higher rate of cell spreading, pseudopod formation and motility, and a higher rate of phagocytosis. The increased deformability and adhesiveness of the PMN as compared to the immature granulocyte may be a reflection of an altered relationship between relaxing and contracting systems at the cell periphery during maturation and/or changes in the sol-gel state of macromolecules at the cell periphery. This concept is supported by the change in surface properties of the PMN toward those of the immature granulocyte at cold temperature (4°C). The increased deformability and reduced surface negative charge of the PMN could facilitate adhesiveness and pseudopod formation and, thereby, increase cell-surface and cell-particle contact with enhancement of motility and phagocytosis. Hence the exit of PMN from bone marrow and circulation and the functional capacity of the PMN may be determined by a process of cytoplasmic maturation during granulopoiesis that adapts the PMN for its essential cell-extracell interactions.

scholarly journals The negative surface charge density of plasmalemma vesicles from wheat and oat roots

FEBS Letters ◽  
1984 ◽  
Vol 167 (1) ◽  
pp. 181-185 ◽  
Author(s):  
Ian M. Møller ◽  
Tomas Lundborg ◽  
Alajos Bérczi
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Negative Surface ◽  
Negative Surface Charge

scholarly journals Negative surface charge density near heart calcium channels. Relevance to block by dihydropyridines.

1987 ◽  
Vol 89 (4) ◽  
pp. 629-644 ◽  
Author(s):  
R S Kass ◽  
D S Krafte
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Surface Potential ◽  
Surface Charge Density ◽  
Ca Channel ◽  
Surface Charges ◽  
Purkinje Fibers ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Induced Changes

We have measured the density of negative surface charges near the voltage sensor for inactivation gating of (L-type) Ca channels in intact calf Purkinje fibers and in isolated myocytes from guinea pig and rat ventricles. Divalent cation-induced changes in the half-maximal voltage for inactivation were determined and were well described by curves predicted by surface potential theory. We measured shifts in inactivation induced by Ca, Sr, and Ba in the single cells, and by Sr in the Purkinje fibers. All of the data were consistent with an estimated negative surface charge density of 1 electronic charge per 250 A2. In addition, the data suggest that Ca, but neither Ba nor Sr, binds to the negative charges with an association constant on the order of 1 M-1. We find that divalent ion-induced changes in surface potential can account for most of the antagonism between these ions and Ca channel block by 1,4-dihydropyridines.

scholarly journals Improvement of Manganese Feroxyhyte’s Surface Charge with Exchangeable Ca Ions to Maximize Cd and Pb Uptake from Water

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1762 ◽  
Author(s):  
Evgenios Kokkinos ◽  
Chasan Chousein ◽  
Konstantinos Simeonidis ◽  
Sandra Coles ◽  
Anastasios Zouboulis ◽  
...  
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Small Scale ◽  
Adsorption Sites ◽  
Exchangeable Ca ◽  
Preparation Step ◽  
Negative Surface ◽  
Ca Ions ◽  
Negative Surface Charge

The surface configuration of tetravalent manganese feroxyhyte (TMFx) was appropriately modified to achieve higher negative surface charge density and, hence, to improve its efficiency for the removal of dissolved Cd and Pb mostly cationic species from water at pH values commonly found in surface or ground waters. This was succeeded by the favorable engagement of Ca2+ cations onto the surface of a mixed Mn-Fe oxy-hydroxide adsorbent during the preparation step, imitating an ion-exchange mechanism between H+ and Ca2+; therefore, the number of available negatively-charged adsorption sites was increased. Particularly, the calcium coverage can increase the deprotonated surface oxygen atoms, which can act as adsorption centers, as well as maintain them during the subsequent drying procedure. The developed Ca-modified adsorbent (denoted as TMFx-Ca) showed around 10% increase of negative surface charge density, reaching 2.0 mmol [H+]/g and enabling higher adsorption capacities for both Cd and Pb aquatic species, as was proved also by carrying out specific rapid small-scale column tests, and it complied with the corresponding strict drinking water regulation limits. The adsorption capacity values were found 6.8 μg·Cd/mg and 35.0 μg·Pb/mg, when the restructured TMFx-Ca adsorbent was used, i.e., higher than those recorded for the unmodified material.

Importance of surface charge characteristics when selecting soils for wastewater re-use

Soil Research ◽  
2005 ◽  
Vol 43 (8) ◽  
pp. 915 ◽  
Author(s):  
I. R. Phillips ◽  
K. J. Sheehan
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Landfill Leachate ◽  
Land Application ◽  
Charge Balance ◽  
Adsorption Sites ◽  
Variable Surface ◽  
Ammonium Adsorption ◽  
Negative Surface ◽  
Negative Surface Charge

Land application represents a viable option in the management of wastewater such as landfill leachate. The surface charge and ion adsorption characteristics of the receiving soil will play an important role in the success of this disposal strategy. The surface charge characteristics of 6 soils with contrasting chemical and physical properties were studied using charge balance principles. The point of zero net proton charge density, point of zero salt effect and point of zero net charge, and the concentrations of permanent and variable charge as a function of pH, were determined for each soil. The presence and magnitude of permanent negative surface charge was largely dependant on clay mineralogy. All soils displayed increasing negative surface charge density with increasing pH. The magnitude of increase for any particular soil was dependent on the type and amount of colloids exhibiting variable surface charge. The increased negative surface charge was attributed to the ionisation of functional groups on organic matter, hydrous Fe and Al oxides, and edge sites of kaolinite and smectite. The variation in surface charge with pH conformed to charge balance principles for soils containing a mixture of both permanent and variable surface charge, but not for soils containing predominantly permanent surface charge. Proton-consuming processes (e.g. adsorption on permanent charge sites, neutralisation of inherent alkalinity) influenced the overall charge balance, particularly for soils with predominantly permanent surface charge. Ammonium adsorption from landfill leachate was measured as a function of pH for each soil type. Increased negative surface charge resulted in increased ammonium adsorption, and for most soils the preference of the newly created adsorption sites for ammonium remained relatively constant. Since many soils contain a mixture of colloids with permanent and variable surface charge, these charge characteristics and their effect on individual soil properties, contaminant availability, and contaminant mobility must be taken into account when evaluating the suitability of land for wastewater re-use.

Negative surface charge near sodium channels of nerve: divalent ions, monovalent ions, and pH

1975 ◽  
Vol 270 (908) ◽  
pp. 301-318 ◽  
Keyword(s):  
Charge Density ◽  
Sodium Channel ◽  
Surface Charge ◽  
Diffuse Double Layer ◽  
Divalent Ions ◽  
Fixed Charges ◽  
Tenfold Increase ◽  
Monovalent Ions ◽  
Negative Surface ◽  
Negative Surface Charge

Evidence is given for a high density of negative surface charge near the sodium channel of myelinated nerve fibres. The voltage dependence of peak sodium permeability is measured in a voltage clamp. The object is to measure voltage shifts in sodium activation as the following external variables are varied: divalent cation concentration and type, monovalent concentration, and pH. With equimolar substitution of divalent ions the order of effectiveness for giving a positive shift is: Ba = Sr < Mg < Ca < Co ≈ Mn < Ni < Zn. A tenfold increase of concentration of any of these ions gives a shift of + 20 to + 25 mV. At low pH, the shift with a tenfold increase in Ca 2+ is much less than at normal pH, and conversely for high pH. Solutions with no added divalent ions give a shift of — 18 mV relative to 2 mM Ca 2+ . Removal of 7/8 of the cations from the calcium-free solution gives a further shift of — 35 mV. All shifts are explained quantitatively by assuming that changes in an external surface potential set up by fixed charges near the sodium channel produce the shifts. The model involves a diffuse double layer of counterions at the nerve surface and some binding of H+ ions and divalent ions to the fixed charges. Three types of surface groups are postulated: (1) an acid p K a = 2.88, charge density —0.9 nm -2 ; (2) an acid p K a = 4.58, charge density —0.58 nm -2 ; (3) a base p K a = 6.28, charge density + 0.33 nm -2 . The two acid groups also bind Ca 2+ ions with a dissociation constant K = 28 M. Reasonable agreement can also be obtained with a lower net surface charge density and stronger binding of divalent ions and H + ions.

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