Potentiation of vinblastine crystal formation in vivo by puromycin and colcemid

The quantity of microtubular protein present in unfertilized eggs and zygotes of the sea urchin, Lytechinus pictus was assayed using vincaleucoblastine (VLB). This vinca alkaloid, used at 10^-4 M, induces the formation of highly birefringent crystals (uniaxial, refractive index 1.51, coefficient of BR 1.7 × 10^?3) known to contain microtubular protein. Crystals were measured in vivo with an ocular micrometer and the volume of each crystal was estimated. Total crystal volumes per cell were compared among groups which received VLB alone and other groups which received VLB with puromycin, colcemid or both. Puromycin was shown to have no effect on the VLB crystal volume in the unfertilized eggs, but zygotes incubated with VLB plus puromycin had a larger volume of crystals per cell than zygotes incubated in VLB alone. Colcemid (10^?4 M) clearly and consistently enhanced the volume yield of VLB crystals by a factor of 3 in both unfertilized eggs and zygotes.