Characterization of anti-microbial peptides and proteins from maggots of Calliphoridae and Sarcophagidae fly species (Diptera)

Abstract

Removal of infected wounds using maggots has been known for centuries. Early research has shown that the maggot exosecretion, whole body, and fecal waste products of Calliphoridae and Sarcophagidae species contain a variety of alkaline peptides capable of inhibiting bacterial growth. Since the wide application of antibiotics such as penicillin, a number of bacterial infections have become insensitive to antibiotic treatment. In many of these instances, maggot therapy has been successfully applied for the treatment of chronic wounds. To identify and compare the expression patterns of anti-microbial peptides (AMPs) from some dipteran species, transcriptome analyses were conducted for the maggots of 11 Calliphoridae and Sarcophagidae species. Species of the subfamily Calliphorinae showed relatively higher expression levels of AMPs and anti-microbial proteins compared with those of Luciliinae and Sarcophagidae species. Furthermore, among all of the dipteran species examined, Lucilia illustris exhibited the highest transcription levels of AMPs. Cecropin A2 and defensin, whose expression levels were the highest among the anti-microbial peptides, were synthesized to test their biological activity. The synthesized peptides showed anti-microbial activities without hemolytic activities. In particular, cecropin A2 of L. illustris exhibited the highest anti-microbial activity against all of the bacteria and fungi examined, thereby possessing the potential to be developed as a new alternative to antibiotics. This comparative transcriptomic study may provide new insights into anti-microbial compositions of some dipteran species.