title: Inducible factors with antimicrobial activity after immune challenge in the haemolymph of Red Palm Weevil (Insecta).
abstract: Insects are capable of innate immune responses elicited after microbial infection. In this process, the receptor-mediated recognition of foreign bodies and the subsequent activation of immunocompetent cells lead to the synthesis ex novo of a peptide pool with antimicrobial activity. We investigated the inducible immune response of a coleopteran, Rhynchophorus ferrugineus, challenged with both Gram-negative and Gram-positive bacteria. After immunization, we evaluated the presence of antimicrobial peptides using either biochemical analyses or microbiological techniques. The antimicrobial properties of the newly synthesized protein pool, detectable in haemolymph fractions of low molecular mass, showed strong antibacterial activity against various bacterial strains (Escherichia coli, Pseudomonas sp. OX1, Bacillus subtilis and Micrococcus luteus). In addition to the preliminary study of the mechanism of action of the pool of antimicrobial peptides, we also investigated its effects on bacterial cell walls by means of fluorescence microscopy and scanning electron microscopy. The data suggest that the main effects seem to be directed at destabilizing and damaging the bacterial wall. This study provides data that help us to understand some aspects of the inducible innate immunity in a system model that lacks anticipatory responses. However, the weevil has finely tuned its defensive strategies to counteract effectively microbial infection.
authors.affiliation: Comparative Immunology Laboratory, Department of Theoretical and Applied Sciences, University of Insubria, Varese, Italy.
authors.forename: Maristella
authors.initials: M
authors.lastname: Mastore
authors.affiliation: Comparative Immunology Laboratory, Department of Theoretical and Applied Sciences, University of Insubria, Varese, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Binda Rossetti
authors.affiliation: Cell Physiology Laboratory, Department of Theoretical and Applied Sciences, University of Insubria, Varese, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Giovannardi
authors.affiliation: Department of Biosciences, University degli Studi of Milan, Milan, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Scarì
authors.affiliation: Comparative Immunology Laboratory, Department of Theoretical and Applied Sciences, University of Insubria, Varese, Italy maurizio.brivio@uninsubria.it.
authors.forename: Maurizio F
authors.initials: MF
authors.lastname: Brivio
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000378:metabolism*; D001433:Bacteriolysis; D002473:Cell Wall / Q000378:metabolism* / Q000648:ultrastructure; D001517:Coleoptera / Q000276:immunology*; D004912:Erythrocytes / Q000502:physiology*; D016905:Gram-Negative Bacterial Infections / Q000276:immunology*; D016908:Gram-Positive Bacterial Infections / Q000276:immunology*; D006458:Hemolymph / Q000378:metabolism*; D006461:Hemolysis; D006801:Humans; D007113:Immunity, Innate; D008855:Microscopy, Electron, Scanning
chemical_list: D023181:Antimicrobial Cationic Peptides
keywords: Antimicrobial peptides; alternative drugs; coleopteran; innate immunity; insects