Fig.4. Recombinant toxin inside an abdominal ganglion of the ventral nerve cord of silkworm larvae. The recombinant toxin is visualized by the immunogold method. (A) Tracheal epithelial cell (TE) in the ganglion beyond the neural lamella. (B) Magnification of the boxed area in A showing the massive expression of the toxin (arrowheads) in the epithelial cell in close vicinity to the nucleus (N). Note the viral particles (V) within the nucleus. (C) The toxin in the neuropile region of an abdominal ganglion (arrowheads). The presence of the toxin on the axonal membrane (am) in the neuropile is obvious. (D) Section from a ganglion in close vicinity to a tracheal cell at the perineural region from a healthy silkworm larva paralyzed by injection of an overdose (3µg100mg^-1bodymass) of AaIT and visualised with immunogold labeling (see Materials and methods). (E) High magnification of the boxed area in D, where the injected AaIT was undetectable (compare to B). A, axon; am, axonal membrane; m, mitochondria; N, nucleus; s, synapse; TE, tracheal epithelium; V, viral particle; NL, neural lamella; LS, gleal lacunar system. Scale bar, 2µm (A), 0.35µm (B,E), 0.25µm (C) and 1.5µm (D).