Morphology and Growth Behaviour of Myelin Figures of Lecithin

Abstract
Growth behaviour and morphological features of myelin figures in egg-yolk lecithin/hydrophilic liquid systems were investigated by microscopic observation at room temperature. The morphological features were conveniently classified into three steps according to the time of growth. In the first step, myelin figures with a simple rod-like form rapidly grew all together perpendicularly to the circumference of a lecithin block into the medium. In the second step, more complicated forms, such as helical and coiling ones, occurred. In the third step, the parts where a contact between surfaces of neighbouring rods had occurred wcre associated, fused and transformed into a mosaic structure. The representative growth mechanism of each of these three steps was dependent mainly on a diffusion of aggregates of lecithin molecules towards myelin figures near their roots, on a lateral diffusion in the bilayer along the long axis of a myelin figure and on a lateral diffusion in the bilayer around the long axis, respectively.