Membrane model: Association of inorganic cations with phospholipid monolayers

Rojas, Eduardo; Tobias, Julian M.

doi:10.1016/0926-6585(65)90047-6

Cited by 209 publications

(30 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The continued neutralization of negative groups might result in less severe changes in the spore so that a smaller loss of spore material and hence a smaller fall in turbidity would result. Calcium ions bound to membranes may be displaced by sodium or potassium ions (Rojas & Tobias, 1965) and, for example, Ehrstrom et al (1973) have shown that calcium ions confer rigidity on membranes isolated from vegetative cells of B. subtilis while monovalent ions like sodium have a negligible ordering effect and at high concentrations (0.1 to 1.0 M) cause disorganization. Joos & Carr (1967) have also shown that in the physiological pH range, membranes containing phosphotidylserine, triphosphoinositide and phosphotidylethanolamine possess many calcium binding groups and can show large variations in bound ions with comparatively small pH changes, while Papahadjopoulos & Ohki (I 969) found that phospholipid membranes with calcium ions present on one side are stable only if the other side is lowered to pH 3.0.…”

Section: Discussionmentioning

confidence: 99%

Changes in Spores of Clostridium bifermentans Caused by Treatment with Hydrogen Peroxide and Cations

Waites¹,

Wyatt²,

King³

et al. 1976

Journal of General Microbiology

View full text Add to dashboard Cite

SUMMARYSpores of Clostridium bifermentans were treated with hydrogen peroxide until their peripheries had lost refractility. The centres of such spores only retained refractility at acid pH. Adding monovalent cations or increasing the pH caused the treated spores to lose their remaining refractility and decreased the turbidity of spore suspensions. Divalent cations prevented or reversed this loss of central refractility and decreased the fall in turbidity. Calcium ions also prevented but did not reverse the loss of central refractility which occurred on drying or applying pressure. Electron micrographs of spores treated with hydrogen peroxide showed that the cortex was depleted or absent and that the loss of central refractility was accompanied by protoplast swelling. It is suggested that divalent cations make spores resistant to drying and pressure by cross-linking negatively charged groups within the protoplast, and that together with hydrogen ions they neutralize the negatively charged groups, thus preventing the swelling of the protoplast, loss of refractility and fall in extinction which occur when divalent cations are replaced by monovalent cations.

show abstract

Section: Discussionmentioning

confidence: 99%

Changes in Spores of Clostridium bifermentans Caused by Treatment with Hydrogen Peroxide and Cations

Waites¹,

Wyatt²,

King³

et al. 1976

Journal of General Microbiology

View full text Add to dashboard Cite

show abstract

“…In lobster axon, enzymic removal of the seine carboxyl group was found to result in a decrease in the amplitude of the action potential, but this was restored when the carboxyl group was restored. Rojas & Tobias (1965) have shown that the binding of calcium to phosphatidyl seine and phosphatidyl 504 ANAPHYLACTIC HISTAMINE SECRETION ethanolamine monolayers is a function of the degree of ionization of the phosphoric and carboxyl groups and at physiological pH the calcium binding of the serine compound is about three times that of the ethanolamine compound. It seems possible therefore that there is an ionic binding of calcium to phosphatidyl serine and that phosphatidyl serine forms at least a part of the membrane binding site or carrier for calcium in the mast cell.…”

mentioning

confidence: 99%

The interaction of calcium and strontium with phosphatidyl serine in the anaphylactic secretion of histamine

Foreman¹,

Mongar²

1973

The Journal of Physiology

View full text Add to dashboard Cite

SUEMARY1. Spontaneous histamine release from isolated mast cells was found to be independent of calcium in the concentration range up to 1 m-mole/l. Phosphatidyl serine did not change the effect of calcium on spontaneous release.2. Spontaneous histamine release was found to vary with the strontium ion concentration. Graded increase in the release occurred as the concentration of strontium was raised from 1 to 10 m-mole/l. Phosphatidyl serine potentiated this action of strontium; the potentiation showed a graded increase as the phosphatidyl seine concentration was raised from 1 to 100 ,jg/ml.3. The activation of anaphylactic histamine release by calcium was potentiated by phosphatidyl serine; the degree of potentiation showed a graded increase as the calcium concentration was raised from 0.1 to 1-0 m-mole/l. 4. The activation of anaphylactic histamine release by strontium showed little, if any, potentiation by phosphatidyl seine.5. The response of the mast cells, in terms of anaphylactic histamine release, to calcium, in the presence of optimal concentrations of phosphatidyl seine, was found to be similar to that observed in the presence of strontium alone.6. These observations are discussed in terms of the concepts of affinity and efficacy of the ions at their receptor sites.

show abstract

“…Rojas & Tobias (1965) reported that at physiological pH, phosphatidylethaniolamine binds Ca whilst phosphatidylcholine (lecithin) weakly repels Ca-. Although the modes of action of cephalin and lecithin on the guinea-pig ileum are at present utnclear, some pharmacological involvemenit is indicated between these compounds and calcium in lls.…”

Section: Pmentioning

confidence: 99%

Proceedings of the British Pharmacological Society

1969

British J Pharmacology

View full text Add to dashboard Cite

(HC3) is a derivative of diphenyl (Long & Schueler, 1954;Schueler, 1955), with high but somewhat variable toxicity. Death in small animals follows respiratory paralysis of delayed onset; this is usually explained as being the result of the inhibition of acetylcholine synthesis. There is evidence that HC3 can affect choline metabolism in other ways and has some actions which occur immediately after its administration (Gardiner, 1961;Domer & Gardiner, 1968). It is uncertain whether these other actions are involved in the lethal intoxication, so we are studying analogues of HC3 in which the balance between the various actions might be different. This communication reports some experiments with the p-terphenyl analogue (TPHC3) of HC3.The LD50 following intraperitoneal injection into mice was 95 ,ug/kg for HC3 and 80 ,ug/kg for TPHC3. These values were determined simultaneously with groups of mice from common stock; on other occasions the values varied between 150 and 50 ,tg/kg for either substance.Both HC3 (10-4M) and TPHC3 (10-4M) strongly inhibited the synthesis of acetylcholine by guinea-pig brain mince and with either the inhibition was less if choline (10-'M) was present.Inhibitory effects were produced by both substances on the responses of isolated tissues involving acetylcholine. The toad isolated rectus abdominis and the guineapig isolated ileum were immediately and reversibly depressed by concentrations greater than 106M; the spontaneous activity of rabbit jejunum was more resistant, being affected when the concentration of HC3 or TPHC3 was raised to 104M.Either substance (0.5 mg/kg intravenously) in chicks produced an immediate curare-like paralysis of the legs and wings which was antagonized by choline (80-100 mg/kg). In the rat the effects on neuromuscular transmission were studied by recording the contractions of both gastrocnemius muscles in response to the stimulation of the sciatic nerves. The nerves were regularly stimulated every 5-10 sec for 0.2

show abstract

Membrane model: Association of inorganic cations with phospholipid monolayers

Cited by 209 publications

References 30 publications

Changes in Spores of Clostridium bifermentans Caused by Treatment with Hydrogen Peroxide and Cations

Changes in Spores of Clostridium bifermentans Caused by Treatment with Hydrogen Peroxide and Cations

The interaction of calcium and strontium with phosphatidyl serine in the anaphylactic secretion of histamine

Proceedings of the British Pharmacological Society

Contact Info

Product

Resources

About