ELECTRON MICROSCOPIC STUDIES ON THE YOSHIDA SARCOMA CELLS INFECTED WITH ECTROMELIA VIRUS

The morphological changes of Yoshida sarcoma cells infected with ectromelia virus were studied with the electron microscope using the thin sections and the phase contrast microscope.Phase contrast microscopic observations: The inclusion bodies were clearly found in the cytoplasm at 72 hours after inoculation. They were frequently revealed as an accumulation of elementary bodies and varied in size. The serious necrotic changes were seen in the cytoplasm at the later stage, and the diffuse distribution of elementary bodies was observed in them.Electron microscopic observations: The inclusion bodies and matrix regions were found in the infected cytoplasm as they were in the case of other tissues. The inclusion bodies were sharply outlined from the cytoplasm. The elementary bodies embedded within the inclusions showed polymorphological appearances and their density was less than that in mature particles. Though empty circles were found in matrix region, it was not proved that the relationship was present between these bodies and mature virus particles.