Insect antimicrobial peptides and their applications

Abstract

Insects are one of the major sources of antimicrobial peptides/proteins (AMPs). Since observation of antimicrobial activity in the hemolymph of pupae from the giant silk moths Samia Cynthia and Hyalophora cecropia in 1974 and purification of first insect AMP (cecropin) from H. cecropia pupae in 1980, over 150 insect AMPs have been purified or identified. Most insect AMPs are small and cationic, and they show activities against bacteria and/or fungi, as well as some parasites and viruses. Insect AMPs can be classified into four families based on their structures or unique sequences: the α-helical peptides (cecropin and moricin), cysteine-rich peptides (insect defensin and drosomycin), proline-rich peptides (apidaecin, drosocin and lebocin), and glycine-rich peptides/proteins (attacin and gloverin). Among insect AMPs, defensins, cecropins, proline-rich peptides and attacins are common, while gloverins and moricins have been identified only in Lepidoptera. Most active AMPs are small peptides of 20–50 residues, which are generated from larger inactive precursor proteins or pro-proteins, but gloverins (~14 kDa) and attacins (~20 kDa) are large antimicrobial proteins. In this mini-review, we will discuss current knowledge and recent progress in several classes of insect AMPs, including insect defensins, cecropins, attacins, lebocins and other proline-rich peptides, gloverins, and moricins, with a focus on structural-functional relationships and their potential applications.

Endogenous egg immune defenses in the yellow mealworm beetle (Tenebrio molitor)

“…Cecropins have broad-spectrum activity against Gram-negative and Gram-positive bacteria, as well as fungi (Yi et al, 2014). We also found a high baseline expression for cecropin in Tribolium castaneum , indicating that these AMPs might be important for prevention of infection in adults.…”

“…Even when induced with Gram-negative bacteria, extracts from primed eggs are only effective against Gram-positive bacteria (Dubuffet et al, 2015). Contrary to defensin 1, attacins are known for their bactericidal activity against Gram-negative bacteria (Yi et al, 2014) and coleoptericins for their activity against both Gram-negative and Gram-positive bacteria (Lee et al, 2013). The very high induction of attacins, coleoptericins and defensins in infected eggs indicates that, although experiments to verify it are needed, Tenebrio eggs are likely well protected against both Gram-negative and Gram-positive bacteria.…”

Insect proteins as a potential source of antimicrobial peptides in livestock production. A review

“…The use of AMPs may be a promising alternative to antibiotics Xiao et al, 2013aXiao et al, ,b, 2015aYoon et al, 2013Yoon et al, , 2014Yi et al, 2014;Wang et al, 2016). The interest in insect AMPs is based on the knowledge from ancient times, where different insects were used in the treatment of a number of different ailments (Table 1).…”

Sustainable farming of the mealworm Tenebrio molitor for the production of food and feed

“…Tenebrio molitor produces a wide range of AMPs constitutively at local sites or in response to infection [19]. AMPs, as a general class of molecules, show a broad spectrum of antimicrobial activity, but specific AMPs range from broadly active to highly specific against particular pathogens [147,148]. Therefore, selective (transgenerational) immune priming would provide a good alternative to antibiotics in addition to avoiding their unwanted effects.…”