Propriétés interfaciales d'une protéine membranaire: la(Na+ + K+) adénosine triphosphatase

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Cationic atmosphere and cation competition binding at negatively charged membranes: pathological implications of aluminum.

Binding of cations to membranes may be the basis for explaining some of the effects of several neurotoxic cations. The binding of Al3+ and the displacement of Ca2+ by Al3+ is studied with the aid of a simple mathematical approach described here and giving the same results when compared to the mathematical formalism described by Nir and Bentz. The method allows the simulation of membranes with low surface charge densities that are relevant for biochemical and pathological implications. Fluorescence quenching of the phospholipid analogue 1-palmitoyl-2-nitrobenzoxadiazol amino caproyl- phosphatidyl choline (C6-NBD-Ptd Cho) embedded in phosphatidyl serine membranes is used to determine the competition between calcium and aluminum for binding. The effect of aluminum in the presence of chelating agents is also studied by quenching experiments. Finally, inhibition of 45Ca2+ binding to phosphatidyl serine has also been investigated in a two-phase system.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Substituted [2-(1-piperazinyl)ethoxy]methyl compounds

Novel substituted [2-(1-piperazinyl)ethoxy]methyl compounds. The present invention related to novel substituted [2-(1-piperazinyl)-ethoxy]methyl compounds of formula STR1 in which R.sub.1 represents a --CONH.sub.2, --CN, --COOH, --COOM or --COOR.sub.3 group, M being an alkali metal and R.sub.3...0info:eu-repo/semantics/publishe

CA2+ ionophoretic properties of negative phospholipids in liposomes and in a pressman cell

The ionophoretic properties of phospholipids in two phase bulk systems has been already demonstrated (Tysonet al. 1976). Phospholipids may also act synergistically with other ionophoretic molecules to translocate Ca2+ (deleers et al. 1983). Some products of the phospholipid metabolism in the lipoxygenase pathway were shown to transport Ca2+ in liposomes membranes (Serhanet al. 1982) and to form stable ionophoretic complexes (Brasseur & Deleers, 1984). However the action of pure phospholipids like phosphatidic acid or phosphatidyl serine as ionophores in lipid membranes remains a matter of debate (Serhan et al. 1981 & 1982; Holmes & Yoss, 1983). The aim of this work is to show that phosphatidic acid (PA), dipalmitoyl phosphatidic acid (DPPA), phosphatidyl serine (PS), diphosphatidyl glycerol (cardiolipin CL), phosphatidyl inositol (PI) and phosphatidyl inositol diphosphate (PIP2) may translocate Ca2+ in a two-phase bulk system. Under suitable conditions they may also transport Ca2+ to different extent through liposomes membranes. © 1984 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Propriétés physico-chimiques des esters du phorbol, agents promoteurs de tumeurs, dans des modèles membranaires

Doctorat en SciencesThèse d'agrégationinfo:eu-repo/semantics/nonPublishe

31P NMR study of the parameters influencing the formation of non-bilayer phases in model membrane.

The influence of various parameters on the formation of non-bilayer phases in mixed cardiolipin/phosphatidylcholine liposomes have been examined by 31P NMR. The Ca++ concentration, the Ca++/cardiolipin ratio and also the phospholipid concentration determine the proportions of the different phases detected on the spectra. In particular, an increase of the cardiolipin concentration favours the induction of isotropic and hexagonal phases. By considering this phospholipid concentration dependence, it is possible to reconcile previous apparently contradictory data on the Ca++ threshold for inducing fusion of this model membrane.Journal Articleinfo:eu-repo/semantics/publishe

Divergent calciphoretic properties of negatively charged phospholipids in a two-phase system and in liposomes.

The ionophoretic properties of several negatively charged phospholipids for transporting calcium ions in an organic phase and across membranes of lipid vesicles have been studied. The amounts of Ca2+ translocated in the organic phase depend on the lipid type but also on the nature of the hydrocarbon chains. Under our experimental conditions, Ca2+ outflow from liposomes is observable with phosphatidic acid derived from egg yolk (PA) and with bovine brain phosphatidyl serine (PS) while dipalmitoyl phosphatidic acid (DPPA), cardiolipin (CL), phosphatidyl inositol (PI) and phosphatidyl inositol diphosphate (PIP2) remained unactive as calcium ionophores through lipid membranes but active as calcium translocators in an organic phase.Journal Articleinfo:eu-repo/semantics/publishe

Influence of membrane fluidity upon ionophore-mediated calcium transport in liposomes

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Protonophoretic activity of hypoglycemic sulfonylureas in black lipid membranes

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Interaction of phorbol esters with lipid monolayers or bilayers

SCOPUS: ar.jinfo:eu-repo/semantics/publishe