Table 1.
Carbohydrate distribution in eggs of unactivated eggs of S. japonicum, demonstrated by ultrastructural lectin cytochemisty on resin sections.
Figure 1.
Hatching of the egg of S. japonicum, light microscopy.
A. Activated larva prior to translocation in the shell. The egg on the left hand side contains an activated larva. Here the miracidium lies longitudinally in the egg and its terebratorium is clearly evident. B. The same larva has turned so that it lies across the egg. C. Egg immediately after shell rupture. The outer envelope and vacuoles are swelling and obscure the now smaller shell. D. The outer envelope is now markedly expanded and the miracidium swims actively within its increasingly viscous matrix. The shell lies to the bottom left of the figure, and is slightly out of focus. Abbreviations: OE- outer envelope; Mir- miracidium; S-shell; T-terebratorium.
Figure 2.
Eggs of S. japonicum, shown by TEM, prepared by HPF and cryo-substitution.
A. Anterior region of a miracidium, showing the terebratorium. The miracidium is enveloped by, in turn, the lacuna, containing lipoid bodies, the inner and outer envelopes, and the shell. Inpocketings of the outer envelope (asterisk) occur at the boundary of the inner and outer envelopes. B. Posterior end of the miracidium in the lacuna. Note the septate desmosomes (arrows) separating the epithelial plates of the miracidial tegument. Abbreviations: Cil- cilia; IE- inner envelope; L- lacuna; LB- lipoid bodies; Mir- miracidium; S- shell; Ter- terebratorium.
Figure 3.
Eggs of S. japonicum, shown by TEM, prepared by HPF and cryo-substitution.
A. Anterior region showing terebratorium of miracidium. B. Vacuole in lacuna of egg. C. Higher magnification of a vacuole. D. Aggregration of lipoid bodies in a vacuole. Abbreviations: Cil- cilia; IE- inner envelope; L- lacuna; LB- lipoid bodies; Mir- miracidium; S- shell; Teg- tegument; Ter- terebratorium; V-vacuole.
Figure 4.
Eggs of S. japonicum, shown by TEM, prepared by HPF and cryo-substitution.
A. Inner and outer envelope. Note the boundary between the shell and outer envelope (arrows). B. Pore in shell. Aggregations of a granular material lie in the outer envelope just beneath the pore (arrows). C. Rosettes in a vacuole. D. High magnification view of rosettes. E. Ciliary rootlet of miracidial tegument. Scale bar = 1 micron. F. High magnification of lacuna. The matrix of the lacuna is granular Scale bar = 0.5 microns.
Figure 5.
Eggs of S. japonicum induced to hatch in water or praziquantel, shown by TEM, prepared by HPF and cryo-substitution.
A. Praziquantel-treated egg. Note the separation of the shell and the outer envelope (arrows). The inner envelope is partially degraded. B. Praziquantel-treated egg, showing separation of the shell from the outer envelope (arrows). C. Shell of an egg hatched in water, at the site of fracture. D. Egg hatched in water. A vacuole with mostly degraded rosettes is shown. E. Egg hatched in water, showing partially degraded rosettes. Abbreviations: IE- inner envelope; OE- outer envelope; S- shell; V-vacuoles.
Figure 6.
Miracidia of S. japonicum, fixed immediately after shell rupture for conventional processing for TEM.
A. Low magnification image showing miracidium within the expanded lacuna. The penetration glands are evident in the miracidium. B. Expanded lacuna with numerous membranes (arrows). C. Outer envelope. Note that the external fibrils appear to be unravelling. Partly degraded rosettes are shown (arrows). D. Lacuna, showing membrane body, presumably a vacuole. Cil- cilia; Gl Nu- nuclei of penetration glands; Mir- miracidium; OE- outer envelope.
Figure 7.
Lectin cytochemistry of S. japonicum eggs, shown by TEM, prepared by HPF and cryo-substitution.
The panels show representative regions with positive localization with the lectin. A–D Con A cytochemistry. A. Lipoid bodies B. Lysosome in inner envelope. C. Rosettes in vacuoles; D. Penetration gland of miracidium. E. WGA labelling in lacuna surrounding the terebratorium. F. UEA in pore of shell. G. PNA in pore of shell. H. WGA in lipoid body. I. WGA in pore.