In Vitro Evaluation of the Antibacterial Activity of the Peptide Fractions Extracted from the Hemolymph of Hermetia illucens (Diptera: Stratiomyidae)

Abstract

Antimicrobial peptides (AMPs) are a chemically and structurally heterogeneous family of molecules produced by a large variety of living organisms, whose expression is predominant in the sites most exposed to microbial invasion. One of the richest natural sources of AMPs is insects which, over the course of their very long evolutionary history, have adapted to numerous and different habitats by developing a powerful innate immune system that has allowed them to survive but also to assert themselves in the new environment. Recently, due to the increase in antibiotic-resistant bacterial strains, interest in AMPs has risen. In this work, we detected AMPs in the hemolymph of Hermetia illucens (Diptera, Stratiomyidae) larvae, following infection with Escherichia coli (Gram negative) or Micrococcus flavus (Gram positive) and from uninfected larvae. Peptide component, isolated via organic solvent precipitation, was analyzed by microbiological techniques. Subsequent mass spectrometry analysis allowed us to specifically identify peptides expressed in basal condition and peptides differentially expressed after bacterial challenge. We identified 33 AMPs in all the analyzed samples, of which 13 are specifically stimulated by Gram negative and/or Gram positive bacterial challenge. AMPs mostly expressed after bacterial challenge could be responsible for a more specific activity.

Hermetia illucens as a Source of Antimicrobial Peptides – A Review of in vitro and in vivo Studies

“…In addition to direct antimicrobial activity, AMPs inhibit biofilm formation and destabilize biofilm structures (Saeed et al, 2022). The experiment carried out by Scieuzo et al (2023) allowed for the recognition of 33 HI-derived AMPs in all samples analyzed, 13 of which are specifically stimulated by Gram-negative and/or Gram-positive bacteria. An important note is that the expression of some AMPs can be induced upon stimulation by specific bacteria.…”

Larval Frass of Hermetia illucens as Organic Fertilizer: Composition and Beneficial Effects on Different Crops

“…Insect bioconversion systems can upcycle a high amount of heterogeneous substrates from organic waste streams into high value proteins and lipids in the form of insect larval biomass, suitable for food and feed. Other products obtained from the insects rearing, in addition to protein and lipids, are antimicrobial peptides [21], chitin, and its derived chitosan [22][23][24]. Larvae can be used as feed to chickens, fish, and pigs because of their high protein content [25,26].…”

Usage of chitosan from Hermetia illucens as a preservative for fresh Prunus species fruits: a preliminary analysis

“…The black soldier fly (Hermetia illucens L.) (BSF) is the most widely reared species in Europe for feed production and waste management [38]. Indeed, BSF larvae, attracted by specific organic volatile compounds [39], can fed on a variety of organic substrates, resulting in a body mass with a high protein and lipid content that can be used for the production of animal feed, biofuels, in cosmetic and biomedical industry [40][41][42][43][44][45][46][47][48][49][50][51]. The pupal exuviae released by BSF during the transition from the pupal to the adult stage is one of the main waste products of its breeding and contains up to 25% chitin that can be purified to produce chitosan [52].…”