Fig. 2.

Pathologic changes in cells of intestine epithelium of sea cucumbers with APED. (a) A cytopathic cell with two vesicles full of virions (arrow). Bar, 200 nm. (b) A nucleus of virus-infected cell was of homogenous materials and hyper-stained, with no nucleoli observed, and the endoplasmic reticulum obviously swelled and formed a separation cisternae (arrow) between the nucleus and the cytoplasm. Bar, 200 nm. (c) Empty vesicles dispersed in granular areas of cytopathic cell of intestine epithelium, some with clear membrane (arrow), and some with blurry margins (arrowhead). Bar, 200 nm. (d) Virus-containing vesicles in cytopathic cells of intestine, in which some virus are light-colored in the center (arrow) as if they are hollow and some are over-colored with petal-like pattern (arrowhead). Orderly tubular structures can also be found around the vesicles. Bar, 50 nm. Inset: a typical virus particle, with an envelope and regular petal-like surface projections (arrow) surrounding the periphery of the particle. Bar, 100 nm.