FIG. 1.

Effect of chemical agents on virus core structure. Purified cores were treated with different chemical agents using the concentrations indicated in the figure. Representative electron microscopy images of purified cores stained with 2% uranyl acetate after the indicated treatments are shown (left). ^a, the effect of virus core incubation with Triton X-100 concentrations higher than 2% could not be evaluated due to interference with electron microscopy. ∗, structure not detected after treatment with any concentration of the indicated chemical agent below the maximum value shown within each column.