Figure 3

Putative glutamine synthetase immunoreactivity (GS-IR, green) in the brain of G. insensibilis. Cell nuclei are counterstained with propidium iodide (red label). (a) to (c) Various glial cell morphologies. Note the end feet and the flocculent profiles of the astrocyte-like cell shown in (a). (d and e) GS-IR in brains of MAD gammarids. Glial cell bodies are present at the surface of the metacercariae. Fine processes (arrow) are apposed to the cystic wall in this stack of confocal sections through a metacercaria (e). (f) and (g) Confocal sections at different levels of an invagination of the cyst wall in a metacercaria. The sections are tangential to the cyst; a section at the surface of the metacercaria (f) shows flocculent glial profiles around the opening of the invagination (arrow); a section taken through the cyst wall reveals the GS-IR wall of the invagination (g); (h) Brain of a MAD gammarid with one live and one encapsulated metacercaria. The asterisk indicates a larva encapsulated and presumably moribund. The arrow points to the invagination of the cyst wall presented in pictures (f) an (g) in a second metacercaria. In (c), (f), (g), (h), single confocal sections; in (a), (b), (c insert), (d), (e), stacks of confocal sections. For clarity the propidium iodide counterstain has been omitted in (a) and in the insert of (c). Anterior is up; h, host; p, parasite. Scale bars: (c), (d), (h) 300 µm; (a), (b), (e), 50 µm; (f), (g), 20 µm.