Material antigenically related to the neuromodulatory
peptide FMRFamide was detected and examined in preparations of the soybean
cyst nematode, Heterodera glycines, and in the free-living nematodes Caenorhabditis elegans and Panagrellus redivivus.
FMRFamide-related
peptides were quantified by an
enzyme-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. glycines examined. The highest specific activity was present in second-stage juveniles and in males, and the lowest in white and yellow females. Total
FMRFamide-related
peptide level per individual was highest in brown females, with 90% of the activity associated with the eggs.
Peptide levels in these eggs and in second-stage juveniles were comparable and increased in adults, especially in females. Chromatographic analysis of
FMRFamide-related
peptide preparations from H. glycines juveniles, C. elegans, and P. redivivus revealed distinct qualitative differences between the infective plant parasite and the free-living nematodes.