Growth factors in asexually reproducing catenulida and macrostomida (Plathelminthes)?

Summary The occurrence and localization of immuno-reactivity (IR) to epidermal growth factor receptor (EGF-r), epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), revealed by the present study, indicate growth-factor-like substances in the asexually reproducing flatworms,Stenostomum leucops andMicrostomum lineare. IR to all three antibodies occurs in the nervous system. Differences in the number of positive cells and intensity of IR during asexual development of new individuals were observed. By confocal scanning laser microscopy, immunopositive growth cones of nerve fibres were seen in developing zooids, and weakly or unstained perikarya were observed in close contact with the positive nerve fibres. Antibodies to the growth factors EGF-r, EGF and bFGF as well as to the neuroactive substances 5-HT and RF-amide had a negative influence on the growth and asexual reproduction of culturedS. leucops. No significant differences in the influence of antibodies to growth factors and antibodies to the neuroactive substances were observed.