Antimicrobial peptides have been found in a variety of invertebrates and vertebrates, where they are thought to serve in the first line of defense against invading microbes. The overall goal of this research is to characterize the primary structure of antimicrobial peptides produced by the intestinal tissues of the sea lamprey, Petromyzon marinus. This phylogenetically and immunologically primitive fish shows distinct developmental stages and ingests a variety of microbes while feeding. The sea lamprey thus offers an unique opportunity to elucidate the structure of antimicrobial peptides from the host defense system of a primitive vertebrate and to examine their role during lamprey development and metamorphosis. Peptides exhibiting antimicrobial activity will be isolated from sealamprey intestines at distinct stages in development and purified via a multiple step purification scheme. Both Edman sequencing and mass spectrometry will be used to determine the amino acid sequence and any post-translational modifications. Finally, peptides will be synthesized in milligram quantities by solid phase peptide synthesis both to confirm their chemical structure and to assay quantitatively their activity against standard bacteria and fungi. This POWRE award allows the PI to do peptide sequencing and peptide synthesis analyses not available at Barnard College and to rebound after disruptive construction in the science building during the second through fourth years of the tenure track.
Characterization of peptide antibiotics from diverse animal sources is important in order to understand their role in host defense and innate immunity. Classified among the oldest living vertebrates, sea lampreys provide an animal system for examining the defense role of antimicrobial peptides at different developmental stages and in terms of molecular evolution of primitive vertebrates.
