The late events of fertilisation in the penaeoidean shrimp Sicyonia ingentis.

Antibodies to sea urchin beta-tubulin and mammalian heavy neurofilaments were used to study the late events of fertilisation in the penaeoidean shrimp Sicyonia ingentis. The neurofilament antibody fortuitously stained centrosomes in eggs, as well as the subacrosomal region and acrosomal filament in sperm. The neurofilament antibody also stained a cortical site in eggs which was associated with the positioning of the mitotic spindle. During pronuclear migration, a large maternal microtubule aster formed in addition to the sperm aster. The activity of the maternal centrosome disappeared during syngamy, while the sperm centrosomes formed the poles of the first mitotic spindle. Colcemid treatment modulated the size of the mitotic spindle and blocked pronuclear migration.