Electron microscopic autoradiographic studies on effects of duck plague virus (DPV) multiplication on nucleoli and their RNA transcription.

The nucleolar structures could be observed in primary chicken embryo cells at 12, 24, 36, 40 and 60 hr after infection with DPV. By means of electron microscopic autoradiography and Bernhard staining method, it could not only demonstrate the existence of nucleoli in infected cells morphologically and functionally, but also further indicate that the incorporation of 3H-Uridine still progressed very rapidly while the viral DNA was intensely replicating, the majority of nucleocapsids were assembled and the maturation of viruses began to appear in the infected cells. In the cells at 24 hr after infection with DPV, the average number of silver grains per unit area on the nucleolar surface was still 82.7% corresponding to that seen in controls. All these phenomena suggest that in DPV-infected cells, the nucleolar structure still exists and its function of RNA transcription keeps going on. These phenomena are different from the previous reports on other species of herpesviruses, and will be discussed in this paper.