VINBLASTINE PRODUCES UNIAXIAL, BIREFRINGENT CRYSTALS IN STARFISH OOCYTES

Abstract

The high degree of ultrastructural organization of microtubular crystals (1, 2) produced in mammalian cells by incubation with Vinca alkaloids, suggested that these crystals would be birefringent in polarized light. We now report the induction by vinblastine sulfate (VBL) of birefringent crystals in unfertilized oocytes of the starfish Pisaster ochraceous Mature ovaries were removed, placed in filtered sea water at 1 1 ° to 13 ° C, and induced to spawn by application of an a ueous extract of starfish radial nerve (3). Oocytes obtained in this manner developed from germinal vesicles to the metaphase spindle of meiosis I, which persisted for about an hour. Most of the oocytes then went on to form polar bodies, at which time further development