Cationic uptake and exchange in Salmonella enteritidis

1972 ◽  
Vol 18 (4) ◽  
pp. 509-513 ◽  
Author(s):  
J. R. Chipley ◽  
H. M. Edwards Jr.
Keyword(s):  
Cell Walls ◽  
Salmonella Enteritidis ◽  
Atp Hydrolysis ◽  
Divalent Cations ◽  
Surrounding Medium ◽  
Monovalent Cations ◽  
Cationic Exchange ◽  
Energy Dependent ◽  
Determining Factor ◽  
Dialysis Time

The use of inorganic cations in cells and purified cell walls of Salmonella enteritidis was investigated. Both the uptake and exchange of radioactive cations were energy-dependent and influenced by pH, by dialysis time and temperature, and by the ionic content of the surrounding medium. Cell walls bound 47Ca2+ to the greatest extent, followed in order by 65Zn2+, 54Mn2+, and 59Fe3+. Another determining factor for cationic exchange was valency, with divalent cations exchanging to the greatest extent, followed by trivalent and monovalent cations, respectively. The greatest amount of exchange occurred between a radioisotope and a stable isotope of the same species. All losses of radioactivity were dialyzable indicating that this exchange involves very small moieties, perhaps the cation alone. Both 2,4-dinitrophenol (DNP) and N,N′-dicyclohexylcarbodiimide (DCCD) significantly decreased autologous exchange, cationic exchange, and cationic uptake in either cells or cell walls. It was postulated that these two compounds either inhibited ATP hydrolysis or reacted with membrane sites such that the membrane could no longer undergo configurational changes associated with cationic transport or exchange.

Cation exchange in cell walls of gram-positive bacteria

1976 ◽  
Vol 22 (7) ◽  
pp. 975-982 ◽  
Author(s):  
Robert E. Marquis ◽  
Kathleen Mayzel ◽  
Edwin L. Carstensen
Keyword(s):  
Cation Exchange ◽  
Cell Walls ◽  
Divalent Cations ◽  
Teichoic Acid ◽  
Dry Weight ◽  
High Ionic Strength ◽  
Monovalent Cations ◽  
Anionic Sites ◽  
Gram Positive Bacteria ◽  
Anionic Groups

The relative affinities of various cations for anionic sites in isolated, bacterial cell walls were assessed by means of a technique involving displacement of one cation by another. The affinity series determined was [Formula: see text]. High affinity was correlated with low mobility of the bound ions in an electric field. The net cation-exchange capacities of walls isolated from a variety of bacteria were estimated by preparing the magnesium forms of the walls, washing them well with deionized water to remove supernumerary ions, and then completely displacing the magnesium with Na+ or H+. Total amounts of magnesium displaced varied from 73 μmol per gram dry weight, for walls of the teichoic acid-deficient 52A5 strain of Staphylococcus aureus to about 520 μmol per gram for Bacillus megaterium KM walls. The amount of displacable magnesium was inversely related to the physical compactness of the walls, except for walls of Streptococcus mutans GS-5. It was found that magnesium or calcium ions can each neutralize, or pair with, two anionic groups in walls suspended in ion-deficient media. Previous work had indicated that these ions may pair with only one anionic group at high ionic strength. Therefore, it appeared that there is a great deal of flexibility in the arrangement of charged groups in the wall. It was concluded also that for cells growing in commonly used laboratory media, which generally contain large excesses of monovalent versus divalent cations, there is a mix of small, cationic counterions in the wall and that monovalent cations may predominate even though the wall has higher affinity for divalent ions.

scholarly journals PVA-Based Mixed Matrix Membranes Comprising ZSM-5 for Cations Separation

Membranes ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 114 ◽  
Author(s):  
Fangmeng Sheng ◽  
Noor Ul Afsar ◽  
Yanran Zhu ◽  
Liang Ge ◽  
Tongwen Xu
Keyword(s):  
Divalent Cations ◽  
Sem Analysis ◽  
Limiting Current ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Transport Pathways ◽  
Dispersion Phase ◽  
Fast Transport ◽  
Cationic Exchange ◽  
Matrix Membranes

The traditional ion-exchange membranes face the trade-off effect between the ion flux and perm-selectivity, which limits their application for selective ion separation. Herein, we amalgamated various amounts of the ZSM-5 with the polyvinyl alcohol as ions transport pathways to improve the permeability of monovalent cations and exclusively reject the divalent cations. The highest contents of ZSM-5 in the mixed matrix membranes (MMMs) can be extended up to 60 wt% while the MMMs with optimized content (50 wt%) achieved high perm-selectivity of 34.4 and 3.7 for H+/Zn2+ and Li+/Mg2+ systems, respectively. The obtained results are high in comparison with the commercial CSO membrane. The presence of cationic exchange sites in the ZSM-5 initiated the fast transport of proton, while the microporous crystalline morphology restricted the active transport of larger hydrated cations from the solutions. Moreover, the participating sites and porosity of ZSM-5 granted continuous channels for ions electromigration in order to give high limiting current density to the MMMs. The SEM analysis further exhibited that using ZSM-5 as conventional fillers, gave a uniform and homogenous formation to the membranes. However, the optimized amount of fillers and the assortment of a proper dispersion phase are two critical aspects and must be considered to avoid defects and agglomeration of these enhancers during the formation of membranes.

The role of sodium chloride in the process of induction by lithium chloride in cells of the Rana pipiens gastrula

Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 387-396
Author(s):  
Lester G. Barth ◽  
Lucena J. Barth
Keyword(s):  
Sodium Chloride ◽  
Culture Medium ◽  
Rana Pipiens ◽  
Divalent Cations ◽  
Pigment Cells ◽  
Distilled Water ◽  
Sodium Ions ◽  
Monovalent Cations ◽  
High Concentration

A study of the effects of a series of monovalent cations, Li+, Na+ and K+, and a series of divalent cations, Mn2+, Ca2+ and Mg2+, upon small aggregates of cells taken from the presumptive epidermis of Rana pipiens gastrulae revealed that these ions induce nerve and pigment cells (Barth, 1965). The effectiveness of both series of ions as inductors was similar to their effects on decreasing the electrophoretic mobility of DNA as determined by Ross & Scruggs (1964). When it was found that sucrose in glass-distilled water also would induce nerve and pigment cells the role of ions as inductors came under closer scrutiny. A study of the nature of the induction by sucrose revealed that a relatively high concentration of sodium ions was necessary in the culture medium used after sucrose treatment (Barth, 1966).

scholarly journals The Effect of Calcium Ionophores on Fragmented Sarcoplasmic Reticulum

1972 ◽  
Vol 60 (6) ◽  
pp. 735-749 ◽  
Author(s):  
Antonio Scarpa ◽  
Judith Baldassare ◽  
Giuseppe Inesi
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Binding ◽  
Calcium Release ◽  
Atp Hydrolysis ◽  
Divalent Cations ◽  
Electron Microscopic ◽  
Microscopic Appearance ◽  
Calcium Accumulation ◽  
Calcium Dependent ◽  
Dependent Atpase

X-537 A and A 23187, two antibiotics which form liphophilic complexes with divalent cations, function as ionophores in vesicular fragments of sarcoplasmic reticulum (SR). Addition of either ionophore to SR preloaded with calcium in the presence of adenosine triphosphate (ATP), causes rapid release of calcium. Furthermore, net calcium accumulation by SR is prevented, when the ionophores are added to the reaction mixture before ATP. On the contrary, ATP-independent calcium binding to SR is not inhibited. This effect is specific for the two antibiotics and could not be reproduced, either by inactive derivatives, or by other known ionophores. Neither ionophore produces alterations of the electron microscopic appearance of SR membranes or inhibition of the calcium-dependent ATPase. In fact, the burst of ATP hydrolysis obtained on addition of calcium, is prolonged in the presence of the ionophores. Lanthanum inhibits ATP-independent calcium binding to SR, ATP-dependent calcium accumulation and calcium-dependent ATPase. However, addition of lanthanum to SR preloaded in the presence of ATP, does not cause calcium release. The reported experiments indicated that: (a) ATP-dependent calcium accumulation by SR results in primary formation of calcium ion gradients across the membrane. (b) Most of the accumulated calcium is not available for displacement by lanthanum on the outer surface of the membrane. (c) Calcium ionophores induce rapid equilibration of the gradients, by facilitating cation diffusion across the membrane.

scholarly journals How does ryanodine modify ion handling in the sheep cardiac sarcoplasmic reticulum Ca(2+)-release channel?

1994 ◽  
Vol 104 (3) ◽  
pp. 425-447 ◽  
Author(s):  
A R Lindsay ◽  
A Tinker ◽  
A J Williams
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Relative Permeability ◽  
Single Channel ◽  
Divalent Cations ◽  
Monovalent Cations ◽  
Channel Conductance ◽  
Single Channel Conductance ◽  
Release Channel ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Conduction Pathway

Under appropriate conditions, the interaction of the plant alkaloid ryanodine with a single cardiac sarcoplasmic reticulum Ca(2+)-release channel results in a profound modification of both channel gating and conduction. On modification, the channel undergoes a dramatic increase in open probability and a change in single-channel conductance. In this paper we aim to provide a mechanistic framework for the interpretation of the altered conductance seen after ryanodine binding to the channel protein. To do this we have characterized single-channel conductance with representative members of three classes of permeant cation; group 1a monovalent cations, alkaline earth divalent cations, and organic monovalent cations. We have quantified the change in single-channel conductance induced by ryanodine and have expressed this as a fraction of conductance in the absence of ryanodine. Fractional conductance seen in symmetrical 210 mM solutions is not fixed but varies with the nature of the permeant cation. The group 1a monovalent cations (K+, Na+, Cs+, Li+) have values of fractional conductance in a narrow range (0.60-0.66). With divalent cations fractional conductance is considerably lower (Ba2+, 0.22 and Sr2+, 0.28), whereas values of fractional conductance vary considerably with the organic monovalent cations (ammonia 0.66, ethylamine 0.76, propanolamine 0.65, diethanolamine 0.92, diethylamine 1.2). To establish the mechanisms governing these differences, we have monitored the affinity of the conduction pathway for, and the relative permeability of, representative cations in the ryanodine-modified channel. These parameters have been compared with those obtained in previous studies from this laboratory using the channel in the absence of ryanodine and have been modeled by modifying our existing single-ion, four-barrier three-well rate theory model of conduction in the unmodified channel. Our findings indicate that the high affinity, essentially irreversible, interaction of ryanodine with the cardiac sarcoplasmic reticulum Ca(2+)-release channel produces a conformational alteration of the protein which results in modified ion handling. We suggest that, on modification, the affinity of the channel for the group 1a monovalent cations is increased while the relative permeability of this class of cations remains essentially unaltered. The affinity of the conduction pathway for the alkaline earth divalent cations is also increased, however the relative permeability of this class of cations is reduced compared to the unmodified channel. The influence of modification on the handling by the channel of the organic monovalent cations is determined by both the size and the nature of the cation.(ABSTRACT TRUNCATED AT 400 WORDS)

Interaction of lipids with intestinal brush border membrane preparations

1982 ◽  
Vol 60 (9) ◽  
pp. 904-909 ◽  
Author(s):  
P. Proulx ◽  
J. McNeil ◽  
I. Brglez ◽  
D. G. Williamson
Keyword(s):  
Brush Border ◽  
Protein Concentration ◽  
Brush Border Membrane ◽  
Divalent Cations ◽  
Monovalent Cations ◽  
Intestinal Brush Border Membrane ◽  
Intestinal Brush Border ◽  
Ph Range ◽  
Assay Conditions ◽  
Lipid Structures

Conditions for uptake of lipids by rabbit intestinal brush border membrane preparations were investigated. A variety of lipids were found to be incorporated, including choline and ethanolamine phosphatides as well as cholesterol, diglyceride, and fatty acid. The incorporation of those lipids tested was enhanced by Ca2+ and other divalent cations but not by monovalent cations. The optimal Ca2+ concentration was approximately 10 mM. The uptake varied with lipid and membrane protein concentration and proceeded at rates which were too rapid to measure under several assay conditions tried. Incorporations were decreased substantially outside the pH range of 6.5–8.0. The effect of one lipid, phosphatidylcholine, on the structural appearance of the membrane fraction was examined by electron microscopy. No free or surface-bound lipid structures could be detected and the membrane fractions appeared to be unchanged after uptake.

ADSORPTIVE AND GAS CHROMATOGRAPHIC PROPERTIES OF VARIOUS CATIONIC FORMS OF ZEOLITE X

1964 ◽  
Vol 42 (10) ◽  
pp. 2340-2350 ◽  
Author(s):  
H. W. Habgood
Keyword(s):  
Ionic Radius ◽  
Adsorption Process ◽  
Divalent Cations ◽  
Chromatographic Retention ◽  
Monovalent Cations ◽  
Zeolite X ◽  
Heats Of Adsorption ◽  
Quadrupole Interactions ◽  
Silver Compound ◽  
Retention Volumes

Gas chromatographic retention volumes for O2, N2, CH4, C2H6, C3H8, C4H10, C2H4, and C3H6 have been measured over a range of temperatures between 25 and 400 °C, on columns of the following ion-exchanged forms of zeolite X: Li+, Na+, K+, Mg++, Ca++, Ba++, and Ag+. In addition, for AgX zeolite, full isotherms have been determined for O2, N2, C2H6, and C2H4; and for NaX zeolite, isotherms for C2H6 and C2H4. The gas chromatographic retention volumes agree well with the isotherms in the case of NaX but are significantly low for AgX, presumably as the result of at least a portion of the adsorption process being slow. The heats of adsorption on NaX agree well with literature values for O2, N2, CH4, and C2H6 but are low for C3H8 and C4H10; further indication of slow processes and hence of a limitation of the g.c. technique. The observations can be correlated qualitatively in terms of the interplay of the following effects: (a) cationic field increases with decreasing ionic radius; (b) shielding of smaller cations is greater—at least in the six-membered oxygen-ring sites; (c) divalent cations, while having greater fields, are only half the number of monovalent cations and tend to be found in less exposed sites; and (d) the polarizing power of silver ion, which also occupies all types of exposed sites, is very strong. The most intense interactions were found with AgX; with ethylene a much stronger complex is formed than has been reported for any other silver compound. The significance of molecular quadrupole interactions on these heteroionic surfaces is shown by the much weaker cationic effects observed with O2 (which has negligible quadrupole moment) than with nitrogen.

Ion behaviour in plant cell walls. IV. Selective cation binding by Sphagnum russowii cell walls

1990 ◽  
Vol 68 (4) ◽  
pp. 773-781 ◽  
Author(s):  
Conrad Richter ◽  
Jack Dainty
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Divalent Cations ◽  
Selectivity Coefficient ◽  
Weak Acid ◽  
Small Population ◽  
Cation Binding ◽  
Trivalent Cations ◽  
Using Data ◽  
A Site

Selective cation binding by Sphagnum russowii cell walls was investigated using data from bicationic potentiometric titrations of isolated cell walls. Selectivity measurements were interpreted in the context of Manning condensation. In titrations with cations of different valency, selectivity favoured the higher valency cation, as expected in Manning condensation. This selectivity generally increased with bathing pH until the wall-bound polyuronic acids became fully ionized (pH > 5). The selectivity coefficient order at full ionization was Na+–Ca2+ > Na+–La3+ > Ca2+–La3+, as predicted by the weak acid Donnan–Manning (WADM) model. Other phenomena also appear to influence binding selectivity. A small population of isolated binding sites are more effectively neutralized by univalent (or divalent) than divalent (or trivalent) cations. High selectivity for cations of lower valency at low pH also suggests a site isolation effect. In bicationic titrations involving divalent cations only, Sr24+ and Ca2+ were bound by the cell wall with approximately equal effectiveness, as predicted by the WADM model. However, cation or binding site specificities probably account for the favoured binding of Ca2+ over Mg2+ by the cell wall. Key words: ion exchange, cell wall, selectivity.

scholarly journals First Evidence for Existence of an Uphill Electron Transfer through the bc1 and NADH-Q Oxidoreductase Complexes of the Acidophilic Obligate Chemolithotrophic Ferrous Ion-Oxidizing Bacterium Thiobacillus ferrooxidans

2000 ◽  
Vol 182 (12) ◽  
pp. 3602-3606 ◽  
Author(s):  
A. Elbehti ◽  
G. Brasseur ◽  
D. Lemesle-Meunier
Keyword(s):  
Electron Transfer ◽  
Electron Donor ◽  
Thiobacillus Ferrooxidans ◽  
Atp Hydrolysis ◽  
Experimental Results ◽  
Pyridine Nucleotides ◽  
Electron Transfer Pathway ◽  
Reducing Equivalent ◽  
Electron Transfer Pathways ◽  
Energy Dependent

ABSTRACT The energy-dependent electron transfer pathway involved in the reduction of pyridine nucleotides which is required for CO2fixation to occur in the acidophilic chemolithotrophic organismThiobacillus ferrooxidans was investigated using ferrocytochrome c as the electron donor. The experimental results show that this uphill pathway involves abc 1 and an NADH-Q oxidoreductase complex functioning in reverse, using an electrochemical proton gradient generated by ATP hydrolysis. Based on these results, a model is presented to explain the balance of the reducing equivalent from ferrocytochrome c between the exergonic and endergonic electron transfer pathways.

Role of the Sarcoplasmic Reticulum Ca2+-ATPase on Heat Production and Thermogenesis

2001 ◽  
Vol 21 (2) ◽  
pp. 113-137 ◽  
Author(s):  
Leopoldo de Meis
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atp Hydrolysis ◽  
Surrounding Medium ◽  
Chemical Energy ◽  
The Past ◽  
Sarcoplasmic Reticulum Membrane ◽  
Membrane Bound ◽  
Hydrolysis Of ◽  
Heat Released

The sarcoplasmic reticulum of skeletal muscle retains a membrane bound Ca2+-ATPase which is able to interconvert different forms of energy. A part of the chemical energy released during ATP hydrolysis is converted into heat and in the bibliography it is assumed that the amount of heat produced during the hydrolysis of an ATP molecule is always the same, as if the energy released during ATP cleavage were divided in two non-interchangeable parts: one would be converted into heat, and the other used for Ca2+ transport. Data obtained in our laboratory during the past three years indicate that the amount of heat released during the hydrolysis of ATP may vary between 7 and 32 kcal/mol depending on whether or not a transmembrane Ca2+ gradient is formed across the sarcoplasmic reticulum membrane. Drugs such as heparin and dimethyl sulfoxide are able to modify the fraction of the chemical energy released during ATP hydrolysis which is used for Ca2+ transport and the fraction which is dissipated in the surrounding medium as heat.

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