OA is found in the central and peripheral nervous systems. OA is found in the central and peripheral nervous systems. OA was labeled with an OA-specific primary antibody and an Alexa-488 (green)-conjugated secondary antibody; DAPI was used as a counterstain (blue). Arrowheads indicate nerve chords, nerve fibers or cell bodies. (A) OA is localized to anterior ganglia (AG) and posterior ganglia (PG) in the head of the adult male worm, a finding that is supported by synapsin co-labeling (B,C; in red). The AG are located posterior of the oral sucker, whereas the PG are anterior of the ventral sucker. Non-specific surface labeling of OA in (A) is indicated with an asterisk. (D-H) OA is found in the longitudinal nerve chords of the CNS and PNS in both males (D,E) and females (F-H). (E,G,H) At higher magnification, OA is identified in cell bodies. (I) An octopaminergic neuron lines the parasite's caecum (CE), indicated by arrowheads. (J) OA is present in what appears to be the submuscular peripheral nerve net of the PNS. (K) Worms were also probed with anti-OA antibody pre-adsorbed with OA or (L) secondary antibody alone: fluorescence, if noted, was non-specific. OA is also detected in D7 schistosomula, indicated by labeling with Alexa-488-conjugated antibody. Innervation of the PNS (M,N) and possibly of the CG (O) is visible. (P) The secondary antibody alone did not yield non-specific labeling. Scale bars: 100 μm at low magnification (20×) in panels A, B, D, F, K and L; 20 μm at high magnification (63×) in panels C, E, G, H-J, M-P. Nelly El-Sakkary et al. Dis. Model. Mech. 2018;11:dmm033563 © 2018. Published by The Company of Biologists Ltd