ANTIGENICITY TO NEUROPEPTIDE-F (NPF) IN STENOSTOMUM-LEUCOPS AND MICROSTOMUM-LINEARE

The first 'native' flatworm regulatory peptide, neuropeptide F (NPF) has recently been isolated and sequenced from the cestode Moniezia expansa (see Maule et al., 1991) and the turbellarian Artioposthia triangulata, (see Curry er al., 1992). NPF belongs to the neuropeptide Y (NPY) superfamily and the antiserum is known to show crossreactivity to the vertebrate neuropeptides of the NPY superfamily. It terminates in RFamide, like the invertebrate neuropeptides FMRFamide and RFamide, and may cross-react with neuropeptides of the FMRFamide family. Strong immunoreactivity (IR) to FMRF- and RF-amide has been demonstrated in members of most flatworm groups. In the present study, IR to NPF (diluted 1:1000) is demonstrated in Stenostomum leucops (Catenulida) and Microstomum lineare (Macrostomida). The controls included: omitting primary antibody, using non-immune serum and liquid-phase absorption with the homologous antigen (1000 ng ml(-1)). The NPF IR pattern was compared to the FMRF and RF-amide IR patterns in order to reveal differences or co-localization. In addition, the sequential appearance of NPF-positive cells in developing zooids was followed and double staining with a-5-HT made to complete the study.