title: Armadillidin H, a Glycine-Rich Peptide from the Terrestrial CrustaceanArmadillidium vulgare, Displays an Unexpected Wide Antimicrobial Spectrum with Membranolytic Activity.
abstract: Antimicrobial peptides (AMPs) are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, there are currently 15 distinct AMP families published so far in the literature, mainly isolated from members of the Decapoda order. Up to now, armadillidin is the sole non-decapod AMP isolated from the haemocytes ofArmadillidium vulgare, a crustacean isopod. Its first description demonstrated that armadillidin is a linear glycine-rich (47%) cationic peptide with an antimicrobial activity directed towardBacillus megaterium. In the present work, we report identification of armadillidin Q, a variant of armadillidin H (earlier known as armadillidin), from crude haemocyte extracts ofA. vulgareusing LC-MS approach. We demonstrated that both armadillidins displayed broad spectrum antimicrobial activity against several Gram-positive and Gram-negative bacteria, fungi, but were totally inactive against yeasts. Membrane permeabilization assays, only performed with armadillidin H, showed that the peptide is membrane active against bacterial and fungal strains leading to deep changes in cell morphology. This damaging activity visualized by electronic microscopy correlates with a rapid decrease of cell viability leading to highly blebbed cells. In contrast, armadillidin H does not reveal cytotoxicity toward human erythrocytes. Furthermore, no secondary structure could be defined in this study [by circular dichroism (CD) and nuclear magnetic resonance (NMR)] even in a membrane mimicking environment. Therefore, armadillidins represent interesting candidates to gain insight into the biology of glycine-rich AMPs.
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Verdon
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Coutos-Thevenot
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Marie-Helene
authors.initials: MH
authors.lastname: Rodier
authors.affiliation: Centre de Biophysique Moléculaire, CNRS UPR4301 Orléans, France.
authors.forename: Celine
authors.initials: C
authors.lastname: Landon
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Segolene
authors.initials: S
authors.lastname: Depayras
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Cyril
authors.initials: C
authors.lastname: Noel
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: La Camera
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Bouziane
authors.initials: B
authors.lastname: Moumen
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Greve
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Bouchon
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Berjeaud
authors.affiliation: Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Braquart-Varnier
keywords: antimicrobial peptide; crustacean; glycine-rich peptide; membrane permeabilization; mode of action; scanning electron microscopy; transmission electron microscopy