title: Purification and characterization of an antimicrobial peptide, insect defensin, from immunized house fly (Diptera: Muscidae).
abstract: The house fly, Musca domestica L. (Diptera: Muscidae), is involved in phoretic movement of pathogenic agents, but it has a very efficient defense mechanism against infection. It is believed that antimicrobial peptides play a significant role in the defense system of the house fly. Here, we isolated a peptide from the immunized house fly pupae, measured its molecular mass (3987.6 Da) by matrix-assisted laser desorption ionization/time of flight-mass spectrometry, and determined its amino acid sequence by using the Procise Protein Sequencing System (Applied Biosystems, Foster City, CA). The peptide was confirmed as a member of the insect defensin family. It displayed high activity against gram-positive bacteria but lower activity against gram-negative bacteria and fungi. Reverse transcription-polymerase chain reaction showed that the house fly defensin gene was constitutively expressed in naive pupae and strongly up-regulated after immunization. House fly defensin is an amphiphilic peptide with a structure similar to that of the CSalphabeta scaffold of insect defensin A from the flesh fly, Phormia terraenovae Robineau-Desvoidy. To our knowledge, this is the first isolated and characterized house fly antimicrobial peptide, and our work may provide useful information for developing pharmacologically active antimicrobial agents.
authors.affiliation: School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: X L
authors.initials: XL
authors.lastname: Dang
authors.forename: Y S
authors.initials: YS
authors.lastname: Wang
authors.forename: Y D
authors.initials: YD
authors.lastname: Huang
authors.forename: X Q
authors.initials: XQ
authors.lastname: Yu
authors.forename: W Q
authors.initials: WQ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D004175:Diptera / Q000276:immunology* / Q000378:metabolism*; D005658:Fungi / Q000187:drug effects
chemical_list: D023181:Antimicrobial Cationic Peptides