Insect immunity: Isolation from a coleopteran insect of a novel inducible antibacterial peptide and of new members of the insect defensin family

• Published in: The Journal of biological chemistry Vol. 266; no. 36; pp. 24520 - 24525
• Main Authors: BULET, P, COCIANCIH, S, DIMARCQ, J.-L, LAMBERT, J, REICHHART, J.-M, HOFFMANN, D, HETRU, C, HOFFMANN, J. A
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 25-12-1991
• Subjects: allomone; allomones; alomonas; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Antibody Formation; antimicrobial properties; Biological and medical sciences; Blood Bactericidal Activity; Blood Proteins - genetics; Blood Proteins - immunology; Blood Proteins - isolation & purification; Chromatography, High Pressure Liquid; Coleoptera; Coleoptera - immunology; Defensins; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; haemolymph; hemolinfa; Hemolymph - chemistry; hemolymphe; Insect Hormones - isolation & purification; Insect Proteins; larvae; larvas; larve; Life Sciences; Molecular Sequence Data; Oxidoreductases; peptide; peptides; peptidos; propiedades antimicrobianas; propriete antimicrobienne; Tenebrionidae; Zophobas atratus; Peptides; Arthropoda; Insecta; HPLC chromatography; Invertebrata; Antibacterial agent; Mass spectrometry; Biological activity; Aminoacid sequence
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)54260-5

Injection of heat-killed bacteria into larvae of the large tenebrionid beetle Zophobas atratus (Insecta, Endopterygota, Coleoptera) results in the appearance in the hemolymph of a potent antibacterial activity as evidenced by a plate growth inhibition assay. We have isolated three peptides (A-C) from this immune hemolymph which probably account for most of this activity. Their primary structures were established by a combination of peptide sequencing and molecular mass determination by mass spectrometry. Peptide A, which is bactericidal against Gram-negative cells, is a 74-residue glycine-rich molecule with no sequence homology to known peptides. We propose the name coleoptericin for this novel inducible antibacterial peptide. Peptides B and C are isoforms of a 43-residue peptide which contains 6 cysteines and shows significant sequence homology to insect defensins, initially reported from dipteran insects. This peptide is active against Gram-positive bacteria. The results are discussed in connection with recent studies on inducible antibacterial peptides present in the three other major orders of the endopterygote clade of insects: the Lepidoptera, Diptera, and Hymenoptera.