Mass Isolation of Germinal Vesicles from Starfish Oocytes *

A rapid, simple and efficient isolation procedure for germinal vesicles was developed using fully grown oocytes from the starfish, Asterina pectinifera. It depends on removal of the vitelline coat by trypsin digestion, gentle cell lysis by hypotonic treatment and centrifugation on a discontinuous sucrose gradient. The germinal vesicles isolated by this method are not clumped, fairly uniform in size and morphology, and rimmed with a very thin layer of cytoplasmic embroidery. They appear morphologically very similar to those in the oocytes. Potential applications of this method and possible functions of the cytoplasmic embroidery are discussed.