Author/Editor		Majhenc, J; Božič, B; Svetina, S; Žekš, B
Title		Phospholipid membrane bending as assessed by the shape sequence of giant oblate phospholipid vesicles
Type		članek
Source		Biochim Biophys Acta - Biomembranes
Vol. and No.		Letnik 1664
Publication year		2004
Volume		str. 257-66
Language		eng
Abstract		Vesicle shape transformations caused by decreasing the difference between the equilibrium areas of membrane monolayers were studied on phospholipid vesicles with small volume to membrane area ratios. Slow transforrnations of the vesicle shape were induced by lowering of the concentration of lipid monomers in the solution outside the vesicle. The complete sequence of shapes consisted of a string of pearls, and wormlike, starfish, discocyte and stomatocyte shapes. Thc transformation from discocyte to stomatocyte vesicle shapes was analyzed theorelically to see whether these observations accord with the area difference elasticily (AD8) model. The membrane shape equation and boundary conditions were derived for axisymmetrical shapes for low volume vesicles, part of whose membranes are in contaet. Calculated shapes were arranged into a phase diagram. The theory predicts ihat the transition between discocyte and stomatocyte shapes is discontinuous for reletively high volumes and continuous for low volumes. The calculated shape sequences matched well with the observed ones. By assuming a linear decrease of the equilibrium area differenee with time, the ratio between the nonlocal and local bending constants is in agreement with reported values.
Descriptors		BIOPHYSICS PHOSPHOLIPIDS MEMBRANES, ARTIFICIAL ELASTICITY MODELS, THEORETICAL