Egg-laying hormone peptides in the Aplysiidae family

Lingjun Li, Rebecca W. Garden, Philip D. Floyd, Tatiana P. Moroz, Juliann M. Gleeson, Jonathan V. Sweedler, Ljiljana Pasa-Tolic, Richard D. Smith

Research output: Contribution to journalArticlepeer-review


The nueropeptidergic bag cells of the marine mollusc Aplysia california are involved in the egg-laying behavior of the animal. These neurosecretory cells synthesize an egg-laying hormone (ELH) precursor protein, yielding multiple bioactive peptides, including ELH, several bag cell peptides (BCP) and acidic peptide (AP). While immunohistochemical studies have involved a number of species, homologous peptides have been biochemically characterized in relatively few Aplysiidae species. In this study, a combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS) and electrospray ionization Fourier transform ion cyclotron resonance MS is used to characterize and compare the ELH peptides from related opisthobranch molluscs including Aplysia vaccaria and Phyllaplysia taylori. The peptide profiles of bag cells from these two Aplysiidae species are similar to that of A. californica bag cells. In an effort to characterize further several of these peptides, peptides from multiple groups of cells of each species were extracted, and microbore liquid chromatography was used to separate and isolate them. Several MS-based sequencing approaches are applied to obtain the primary structures of bag cell peptides and ELH. Our studies reveal that α-BCPs are 100% conserved across all species studied. In addition, the complete sequences of ε-BCP and ELH of A. vaccaria were determined. They show a high degree of homology to their counterparts in A. californica, with only a few amino acid residue substitutions.

Original languageEnglish (US)
Pages (from-to)2961-2973
Number of pages13
JournalJournal of Experimental Biology
Issue number21
StatePublished - Nov 1999


  • Aplysia californica
  • Aplysia vaccaria
  • Bag cell peptide
  • Egg-laying hormone
  • Electrospray ionization
  • Fourier transformed ion cyclotron resonance
  • Mass spectrometry
  • Matrix-assisted laser desporption/ionization
  • Microbore liquid chromatography
  • Peptide sequencing
  • Phyllaplysia taylori

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • Agricultural and Biological Sciences (miscellaneous)


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