Biomaterial Database

Effect of temperature and ions on the microviscosity of bilayers from natural phospholipid mixtures. 1982

M Rossignol, and N Grignon, and C Grignon

The thermotropic behaviour of two natural extracts of phospholipids differing by their content in saturated fatty acids and acidic polar heads were studied with the aid of the fluorescent probes : perylene and diphenylhexatriene. The main results are that the bilayers are in a fluid state in the range from -- 5 to 50 degrees C, in the presence as well as in the absence of calcium, and that misleading conclusions may be derived with the perylene probe. The effects of pH and Ca2+/H+ interaction on the microviscosity were studied. In the absence of calcium pH increase fluidizes the bilayers ; when Ca2+ is present the microviscosity is constant over a large pH range. Calculations using the Gouy-Chapman theory suggest that the pH-induced microviscosity changes are controlled by the content in phosphadidylserine, diphosphatidylglycerol and phosphatidic acid of the extracts. Similarly the rigidifying effect of Ca2+ seems to be related to the content in these phospholipids. These hypothesis were confirmed by modifying the content of the extracts in these phospholipids. It is proposed that the behaviour of the two studied extracts results from the high insaturation of their fatty acids, which is typical of biological membranes.

UI	MeSH Term	Description	Entries
D007887	Fabaceae	The large family of plants characterized by pods. Some are edible and some cause LATHYRISM or FAVISM and other forms of poisoning. Other species yield useful materials like gums from ACACIA and various LECTINS like PHYTOHEMAGGLUTININS from PHASEOLUS. Many of them harbor NITROGEN FIXATION bacteria on their roots. Many but not all species of "beans" belong to this family.	Afzelia,Amorpha,Andira,Baptisia,Callerya,Ceratonia,Clathrotropis,Colophospermum,Copaifera,Delonix,Euchresta,Guibourtia,Legumes,Machaerium,Pithecolobium,Stryphnodendron,Leguminosae,Pea Family,Pithecellobium,Tachigalia,Families, Pea,Family, Pea,Legume,Pea Families
D008051	Lipid Bilayers	Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.	Bilayers, Lipid,Bilayer, Lipid,Lipid Bilayer
D008560	Membrane Fluidity	The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.	Bilayer Fluidity,Bilayer Fluidities,Fluidities, Bilayer,Fluidities, Membrane,Fluidity, Bilayer,Fluidity, Membrane,Membrane Fluidities
D010569	Perylene	A 20-carbon dibenz(de,kl)anthracene that can be viewed as a naphthalene fused to a phenalene or as dinaphthalene. It is used as fluorescent lipid probe in the cytochemistry of membranes and is a polycyclic hydrocarbon pollutant in soil and water. Derivatives may be carcinogenic.	Perilene,Peri-Dinaphthalene,Peri Dinaphthalene
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D010946	Plants, Medicinal	Plants whose roots, leaves, seeds, bark, or other constituent parts possess therapeutic, tonic, purgative, curative or other pharmacologic attributes, when administered to man or animals.	Herbs, Medicinal,Medicinal Herbs,Healing Plants,Medicinal Plants,Pharmaceutical Plants,Healing Plant,Herb, Medicinal,Medicinal Herb,Medicinal Plant,Pharmaceutical Plant,Plant, Healing,Plant, Medicinal,Plant, Pharmaceutical,Plants, Healing,Plants, Pharmaceutical
D011522	Protons	Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.	Hydrogen Ions,Hydrogen Ion,Ion, Hydrogen,Ions, Hydrogen,Proton
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004161	Diphenylhexatriene	A fluorescent compound that emits light only in specific configurations in certain lipid media. It is used as a tool in the study of membrane lipids.	1,6-Diphenyl-1,3,5-hexatriene,1,6-Diphenylhexatriene,1,6 Diphenylhexatriene
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations