Fig. 2.

PR8 virions observed by SEM. (a) A representative electron micrograph of PR8 virions budding from the cells of allantoic membranes. (b) A representative electron micrograph of virions adsorbed onto a chicken erythrocyte, which was found with allantoic membrane cells under an SEM field. Elliptical and spherical virions can be seen. (c) A higher magnification of the representative electron micrographs of released virions on chicken erythrocytes. Respective shape complexity values are given below the photos. (d) Proportion of shape complexity values of virions visualized by SEM. In total, 197 virions were examined. Bars, 500 nm (a, b); 100 nm (c).