Characterization and biochemical activities of novel functional antimicrobial peptide (AMP) from Trichogramma chilonis

Introduction and Aim: The antimicrobial peptides (AMPs) are generally found in invertebrates, mammals, birds, plants and insects. AMPs produced by insect parasitoids contribute to innate immunity to resist infection due to lack of adaptive immunity. T. chilonis is one of the most effective endoparasitoid wasps for controlling lepidopterous insects. Several attempts have been made to isolate, characterize and develop a commercially viable product of AMPs from various insect sources. The present study aimed to characterize AMP from T. chilonis for potential antimicrobial and anti-cancer properties. Methods: AMP was identified through T. chilonis transcriptome sequence and designed in silico and synthesized. Its purity was quantified using RP-HPLC, and the mass identified by mass spectrophotometry. LC/MS-MS was employed to predict the sequence and the BLAST program used to compare the sequence. AMP was tested for haemolytic activity and antimicrobial activity. Two pathogenic bacteria and fungal strains were used and IC50 values and MIC values were predicted against microbial strains. Results: Synthetic peptide was found to be 95% homogenous with molecular weight of 3.48 kD. The peptide was identified to be a novel antimicrobial peptide consisting of 33 amino acid residues, and has a low computed instability index of -0.1.55 with high hydrophobic ratio of 27.27%. The antimicrobial activity revealed that T. chilonis antimicrobial peptide (TC-AMP) strongly inhibits the growth of selected human bacterial and fungal pathogens. While the haemolytic assay showed that the peptide did not obliterate human RBC in vitro. TC-AMP also showed an efficient inhibition of angiogenesis by in vivo model as evident by inhibition of vascularization. Conclusions: AMP derived from the parasitoid has a potent antibiotic and anti-angiogenesis property. The peptide can be used as a potential antimicrobial and anticancer drug in near future with more detailed studies on its targeted applications.