An increase in the intracellular Ca” concentration of human erythrocytes results in profound morphological changes and loss of plasma membrane in the form of small vesicles [ 1,2]. It is of interest to determine whether this behaviour could be related to a Ca2+-induced instability in the bilayer structure of the membrane lipid. We have therefore examined the influence of Ca2+ on model membrane ...

The intact acrosome of the Mytilus edulis spermatozoon consists of a conical vesicle, the basal side of which is deeply invaginated so that the whole vesicle forms a sheath around a very slender axial rod, about 2.7 micro long, inserted in a tube passing through the nucleus. The annular base of the acrosomal vesical is filled with a homogeneous substance; the outer wall of the vesicle is lined ...