Scanning electron microscopic examination of the secondary constriction of vero cells.

Vero cells (African green monkey kidney in origin) were prepared by the conventional air-drying method and then processed for SEM by a modification of the conductive method based on thiocarbohydrazide-osmium binding. Under SEM, not only metaphase chromosomes but also resting nuclei showed distinct fibres 30 nm in diameter. A few such fibres were found to run across the secondary constriction of the NOR-carrying chromosome.