Unique toxic peptides isolated from sawfly larvae in three continents

Area of Science:

• Biochemistry
• Toxicology
• Zoology

Background:

• D-amino acid peptides are identified as toxins responsible for sawfly larvae poisoning worldwide.
• These unique animal-derived compounds were isolated from sawfly species across Australia, Denmark, and South America.

Purpose of the Study:

• To isolate and characterize toxic peptides from different sawfly species.
• To investigate the origin and properties of these novel animal toxins.

Main Methods:

• Isolation and structural elucidation of toxic peptides from sawfly larvae.
• Comparative analysis of toxin composition across different geographical species.

Main Results:

• Lophyrotomin (octapeptide) is the primary toxin in Australian and Danish sawflies, with minor presence in South American species.
• Pergidin (heptapeptide with phosphoseryl residue) is the main toxin in South American sawflies, also found in smaller amounts in other species.
• This marks the first isolation of a phosphoseryl-containing peptide from an animal source.

Conclusions:

• The identified D-amino acid peptides, lophyrotomin and pergidin, are likely biosynthesized de novo by sawflies, potentially as a defense mechanism.
• The stability of these peptides, due to their configuration, chemical bonding, and lipophilic nature, suggests potential for persistent residues and host effects.
• While microbial synthesis cannot be entirely ruled out, endogenous production is suggested by available evidence.