Novel inducible antibacterial peptides from a hemipteran insect, the sap-sucking bug Pyrrhocoris apterus.
Insects belonging to the recent orders of the endopterygote clade (Lepidoptera, Diptera, Hymenoptera and Coleoptera) respond to bacterial challenge by the rapid and transient synthesis of a battery of potent antibacterial peptides which are secreted into their haemolymph. Here we present the first report on inducible antibacterial molecules in the sap-sucking bug Pyrrhocoris apterus, a representative species of the Hemiptera, which predated the Endoptergotes by at least 50 million years in evolution. We have isolated and characterized from immune blood of this species three novel peptides or polypeptides: (i) a 43-residue cysteine-rich anti-(Gram-positive bacteria) peptide which is a new member of the family of insect defensins; (ii) a 20-residue proline-rich peptide carrying an O-glycosylated substitution (N-acetylgalactosamine), active against Gram-negative bacteria; (iii) a 133-residue glycine-rich polypeptide also active against Gram-negative bacteria. The proline-rich peptide shows high sequence similarities with drosocin, an O-glycosylated antibacterial peptide from Drosophila, and also with the N-terminal domain of diptericin, an inducible 9 kDa antibacterial peptide from members of the order Diptera, whereas the glycine-rich peptide has similarities with the glycine-rich domain of diptericin. We discuss the evolutionary aspects of these findings.
Cociancich
S
S
Unité Propre de Recherche du CNRS Réponse immunitaire et développement chez les Insectes, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France.
Dupont
A
A
Hegy
G
G
Lanot
R
R
Holder
F
F
Hetru
C
C
Hoffmann
J A
JA
Bulet
P
P
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins / Q000302:isolation & purification / Q000494:pharmacology; D002850:Chromatography, Gel; D023082:Defensins; D008401:Gas Chromatography-Mass Spectrometry; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006430:Hemiptera / Q000737:chemistry*; D006458:Hemolymph / Q000737:chemistry; D019476:Insect Proteins; D008969:Molecular Sequence Data; D010455:Peptides / Q000302:isolation & purification* / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D023082:Defensins; D019476:Insect Proteins; D010455:Peptides; C087710:pyrrhocoricin protein, Pyrrhocoris apterus; C087708:hemiptericin protein, Pyrrhocoris apterus