Scanning electron microscopical assessment of protoscoleces treated with praziquantel and MMV665807.

<p>Protoscoleces were incubated in (A) 1% DMSO (control), (B) praziquantel (PZQ), or (C) MMV665807 (the latter two both with 1% DMSO) for 12 hours at 100, 10, 1 and 0.1 ppm and subsequently subjected to scanning electron microscopy (SEM). (A) depicts intact protoscoleces with rostellum (r), including hooks covered by a filamentous network, four muscular suckers (ms) and the protoscolex body (b). The whole protoscolex is covered in microtriches (mt) as shown in the enlarged view of a muscular sucker on the right. (B) Noticeable effects of PZQ on protoscoleces were seen at all concentrations tested (contraction of body and neck region (indicated by arrows), bleb formation (bf), as magnified in the picture most to the right), but the muscular suckers, hooks (h) and microtriches were largely unaffected. (C) MMV665807 led overall to less contraction compared to PZQ, but it induced a striking loss of microtriches and hooks from the rostellum (hl, see especially second picture at 100 ppm) at high concentrations (100, 10 and partially 1 ppm). At low concentrations (0.1 ppm), microtriches and rostellum with hooks were fully intact.