Two novel insect defensins from larvae of the cupreous chafer, Anomala cuprea: purification, amino acid sequences and antibacterial activity
Autor(es): Yamauchi, H.
Resumo: A humoral immune response in larvae of the coleopteran insect, Anomala cuprea has been examined for exploring the molecular basis of host-pathogen interactions. The antibacterial activity against the Gram-positive strain. Micrococcus luteus was detected at a low level in absence of injection. The activity increased strikingly in the hemolymph of the larvae challenged with Escherichia coli, showing the fluctuating profile through a time course, which consists of the static induction phase, the production phase rising to a maximum level, and the reduction phase extending over a long duration. Two peptides were purified and characterized by reverse-phase HPLC, Edman degradation and mass spectrometry. They were isoforms, composed of similar sequences with two amino acid substitutions in 43 residues, and novel members of the insect defensins, cysteine-rich antibacterial peptides. Anomala defensins A and B showed potent activity against Gram-positive bacteria, with slight differences in activity against a few strains of tested bacteria. Anomala defensin B was active at high concentration of 40 mum against the Gram-negative strain, Xenorhabdus japonicus, a pathogen toward the host, A. cuprea larvae. (C) 2001 Elsevier Science Ltd. All rights reserved.
Palavras-Chave: Amino acid sequence; Insect defensin; Antibacterial activity; Innate immunity; Anomala cuprea; Xenorhabdus japonicus
Imprenta: Insect Biochemistry and Molecular Biology, v. 32, n. 1, p. 75-84, 2001
Identificador do objeto digital: 10.1016/S0965-1748(01)00082-0
Descritores: Aedes aegypti - Immune response ; Aedes aegypti - Molecular structure
Data de publicação: 2001
