title: Antimicrobial mode of action of secretions from the metapleural gland of Myrmecia gulosa (Australian bull ant).
abstract: Secretions from exocrine metapleural glands of Myrmecia gulosa (Australian bull ant) exhibit broad-spectrum antimicrobial activity. Treatment of the yeast Candida albicans with metapleural secretion resulted in the rapid and total leakage of K+ ions from cells within 10 min. Ultrastructural analysis of the bacteria Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa, and cells and protoplasts of Candida albicans demonstrated gross damage of the cell membrane and aggregation of the cytoplasmic matrix of treated cells. Degradation of membrane-bound organelles was also observed in Candida albicans. The antimicrobially active components of metapleural secretions were nonpolar and interacted with the phospholipid bilayer, causing damage to the structural integrity of liposomes and the release of carboxyfluorescein. The data suggest that the antimicrobial agents in metapleural secretion act primarily by disrupting the structure and function of the phospholipid bilayer of the cytoplasmic membrane.
authors.affiliation: School of Biological Sciences, Macquarie University, N.S.W., Australia.
authors.forename: J A
authors.initials: JA
authors.lastname: Mackintosh
authors.forename: J E
authors.initials: JE
authors.lastname: Trimble
authors.forename: M K
authors.initials: MK
authors.lastname: Jones
authors.forename: P H
authors.initials: PH
authors.lastname: Karuso
authors.forename: A J
authors.initials: AJ
authors.lastname: Beattie
authors.forename: D A
authors.initials: DA
authors.lastname: Veal
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001409:Bacillus cereus / Q000187:drug effects* / Q000648:ultrastructure; D002176:Candida albicans / Q000187:drug effects* / Q000648:ultrastructure; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure; D004926:Escherichia coli / Q000187:drug effects* / Q000648:ultrastructure; D007313:Insecta / Q000737:chemistry* / Q000382:microbiology; D008081:Liposomes; D008854:Microscopy, Electron; D011188:Potassium; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D008081:Liposomes; D011188:Potassium