FIG. 7.

In situ localization of luciferase activity and detection of viral replication in the skin. At the end of the experiment presented in Fig. 6, the fish were dissected immediately after bioluminescence imaging performed on day 3 p.i. The dissected fish and isolated organs were analyzed for ex vivo bioluminescence. (A) The analysis of one representative fish is presented. The left and right images represent bioluminescence imaging performed before and after dissection, respectively. Op, operculum; Pc, pectoral fin; Pl, pelvic fin; Sk, skin; Do, dorsal fin; Ca, caudal fin; Gi, gills; Mu, muscle; Bc, body cavity. (B) A skin fragment emitting bioluminescence was analyzed by electron microscopy (EM). The left image shows low magnification of the skin epithelium. The right image shows one representative infected epithelial cell at higher magnification. The arrows indicate viral particles present in the nucleus (Nu) and the cytosol (Cy).