title: Novel antibacterial peptides isolated from a European bumblebee, Bombus pascuorum (Hymenoptera, Apoidea).
abstract: We present here the isolation and characterization of four antimicrobial peptides produced by a European bumblebee Bombus pascuorum. A 51-residue insect defensin was characterized which, like the Apis mellifera defensins, had a highly conserved 12-residue extension to its C-terminal compared to defensins from other insects. Monoisotopic mass analysis of the C-terminal of B. pascuorum defensin confirmed that this molecule was C-terminally amidated. This defensin showed strong anti-Gram-positive activity and some anti-fungal activity; also, in contrast to other insect defensins, it showed anti-Gram-negative activity. A 17-residue apidaecin was characterized, showing anti-Gram-negative activity, and differing by a single amino acid substitution from the A. mellifera apidaecin. A 39-residue abaecin was isolated, the largest proline-rich antimicrobial peptide characterized to date, which showed activity against both Gram-negative and Gram-positive bacteria. Finally, we isolated an N-terminally blocked molecule, with a molecular mass of 10,122 Da, which showed activity against Gram-negative bacteria only. These characteristics are reminiscent of hymenoptaecin from the honeybee A. mellifera, but a definitive characterization of this molecule awaits further work. No evidence of lysozyme activity was found in the haemolymph of challenged or naive B. pascuorum.
authors.affiliation: Institute for Animal Health, Pirbright Laboratory, Surrey, U.K.
authors.forename: J A
authors.initials: JA
authors.lastname: Rees
authors.forename: M
authors.initials: M
authors.lastname: Moniatte
authors.forename: P
authors.initials: P
authors.lastname: Bulet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D001516:Bees / Q000737:chemistry*; D001798:Blood Proteins / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D023082:Defensins; D004926:Escherichia coli / Q000187:drug effects; D019476:Insect Proteins; D013058:Mass Spectrometry; D016982:Micrococcus luteus / Q000187:drug effects; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000187:drug effects; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D023082:Defensins; D019476:Insect Proteins; D010455:Peptides; C080586:hymenoptaecin protein, Apis mellifera; C062933:abaecin protein, Apis mellifera; C061361:apidaecin