Unique toxic peptides isolated from sawfly larvae in three continents

D-Amino acid containing peptides have been found to be responsible for sawf ly larvae poisoning in many parts of the world. These compounds, unique in the animal kingdom, were isolated from three different species of sawfly in digenous to Australia, Denmark and South America. The octapeptide, lophyrot omin, is the major toxin in the Australian and Danish species and is presen t in small amounts in the South American sawfly. Pergidin, the main toxin i n the South American sawfly, is a heptapeptide containing a phosphoseryl re sidue. This, as far as we are aware, is the first example of such a peptide to be isolated from an animal source. Small amounts of pergidin have been found in the other two species. All available evidence suggests that both p eptides are biosynthesised 'de novo possibly as a protective device, howeve r it cannot be excluded that microorganisms may be responsible. These compo unds are stable to enzymatic breakdown because of their configuration and t heir strong chemical bonding and lipophilic character provide a potential f or residues to remain in the host animal and cause significant changes. (C) 1999 Elsevier Science Ltd. All rights reserved.