ISOLATION OF NEB-LFAMIDE, A NOVEL MYOTROPIC NEUROPEPTIDE FROM THE GREY FLESHFLY

A methanolic extract of 350000 adult grey fleshflies Neobellieria bull ata, was prepared and screened for myotropic activity. After fractiona tion on the first column, all fractions were screened in two heterolog ous (Locusta oviduct and Leucophaea hindgut) and one homologous (Neobe llieria hindgut) myotropic bioassay. We here report the purification o f one fraction, which stimulates the contractions of the Locusta ovidu ct. Electrospray Mass Spectrometry of the peptide revealed a molecular mass of 1395.82. The primary structure has been determined as AYRKPPF NGSLF-amide. This novel peptide was designated Neb-LFamide. This seque nce is different from the other known myotropic peptides in insects. T he threshold concentration of the synthetic peptide is 1 x 10(-7) M on the Locusta oviduct. On the hindgut of Neobellieria in or Leucophaea, the synthetic peptide is not active. By use of a polyclonal antiserum raised against the synthetic peptide, immunoreactivity was localized in median neurosecretory cells in the pars intercerebralis of the fly brain, indicating that Neb-LFamide is a neuropeptide.