Myelin figure is a peculiar structure which is found in a system of amphiphilic molecules and water. It is a multi-lamellar rod like structure in which stacked bilayers of amphiphiles, alternating with water layers, are concentrically around a rod-like core-axis of water as shown in Fig. 1.
Fig. 2 is cross sectional view of the myelin figures observed by use of a scanning electron micrescope at -180 .
The thickness of one unit (the thickness of lipid bilayer + that of water layer) is an approx. 6 nm. The structural features of a rod are essenrially similar to those of the nerve myelin sheath.
The initial growth process of myelin figures is diffusion-limited with an apparent diffusion coefficient D of approx. 10-6cm2/s in the case of egg-yolk phosphatidylcholine and water system at 25 .

Fig.1





Fig.2

References:

Growth Mechanism of Myelin Figures of Phosphatidylcholine,
I. Sakurai and Y. Kawamura, Growth Mechanism of Myelin figures of Phosphatidylcholine, Biochim. Biophys. Acta, "777", 347(1984).

Cross-Sectional View of Myelin Figures,
I. Sakurai et al., Cross-Sectional View of Myelin Figures, Biochim. Biophys. Acta, "985," 101(1989).

Morphology and Growth Behaviour of Myelin Figures of Lecithin,
I. Sakurai et al., Morphology and Growth Behaviour of Myelin Figures of Lecithin, Mol. Cryst. Liq. Cryst., "130", 203(1985).

Dr. Ikuko Sakurai
Biophysics Lab.
The Institute of Physical and Chemical Research (Riken)
Hirosawa 2-1, Wako, Saitama 351-01, Japan. Fax: 81-(0)48-462-4646
E-mail:isakurai@postman.riken.go.jp

Copyright Akiko Kasahara & K-Lab. Inc., 1995
most recent update 12/1/97