A specific peptide produced during adult diapause of the leaf beetle, Gastrophysa atrocyanea Motschulsky (Coleoptera : Chrysomelidae)

Abstract

In the adult stage of the leaf beetle, Gastrophysa atrocyanea, a diapause-specific peptide appeared at diapause initiation and disappeared after overwintering. Continuous JHA applications induced the diapause breakdown which caused the peptide to decline. To isolate the peptide, we used disk preparative SDS-PAGE, gel filtration HPLC and RP-HPLC. The apparent molecular mass of the peptide was 7.9 kDa with SDS-PAGE and 4466.3 Da by mass spectrometry. The first 36 the N-terminal amino acid sequence of the peptide showed : AVRIGPXDQVXPRIVPERHEXXRAHGRSGYAYXSGG. Antiserum prepared for the peptide was used for western blotting and immunohistochemistry. The results suggested that it is synthesized in the fat body and released into the hemolymph.