Fig. 5.

Transmission electron micrographs of Taura syndrome virus (TSV) from Litopenaeus vannamei. (a) Purified TSV from cesium chloride gradient ultracentrifugation. Most of the hexagonal appearing (in profile) icosahedral particles are full, but several particles lack the viral genome and show only empty capsids. Stain: 2% PTA; (b–d) Ultrastructural changes in TSV-infected cells; (b) The cytosol of an infected cell showing accumulations of putative TSV particles (arrows point to examples) associated with membranes of the rough endoplasmic reticulum (RER), masses of small membranous vesicles (SMV) and a distended mitochondria (Mi); (c and d) Detection of TSV by TEM ISH in water soluble resin-embedded tissues. Accumulations of immuno-gold particles are shown reacting to TSV particles in (c) and (d). Solid arrows in (d) point to clumps of immuno-gold particles marking TSV particles, while hollow arrows point to unmarked virions. Of interest is the dense accumulation of immuno-gold particles within the nuclear membrane. Higher magnifications of this area in this and other cells do not show discrete TSV. Hence, the probe may be reacting to free or un-encapsulated ssRNA of TSV.