FMRFamide-like immunoactivity in Heterodera glycines (Nemata : Tylenchida)

Material antigenically related to the neuromodulatory peptide FMRFamide was detected and examined in preparations of the soybean cyst nematode, Hetero dera glycines, and in the free-living nematodes Caenorhabditis elegans and Panagrellus redivivus. FMRFamide-related peptides were quantified by an enz yme-linked immunosorbent assay. Specific activities were remarkably similar among all of the vermiform members of the three species. FMRFamide-related peptide immunoactivity was present in both sexes and all stages of H. glyc ines examined. The highest specific activity was present in second-stage ju veniles and in males, and the lowest in white and yellow females. Total FMR Famide-related peptide level per individual was highest in brown females, w ith 90% of the activity associated with the eggs. Peptide levels in these e ggs and in second-stage juveniles were comparable and increased in adults, especially in females. Chromatographic analysis of FMRFamide-related peptid e preparations from H. glycines juveniles, C. elegans, and P. redivivus rev ealed distinct qualitative differences between the infective plant parasite and the free-living nematodes.