title: Cytotoxicity of pilosulin 1, a peptide from the venom of the jumper ant Myrmecia pilosula.
abstract: The synthetic peptide pilosulin 1, corresponding to the largest defined allergenic polypeptide found in the venom of the jumper ant Myrmecia pilosula, inhibited the incorporation of [methyl-3H]thymidine into proliferating Epstein-Barr transformed (EBV) B-cells. The LD50 was four-fold lower in concentration than melittin, a cytotoxic peptide found in honey bee venom. Loss of cell viability was assessed by flow cytometry by measuring the proportion of cells that fluoresced in the presence of the fluorescent dye 7-aminoactinomycin D. Examination of proliferating EBV B-cells indicated that the cells lost viability within a few minutes exposure to pilosulin 1. Partial peptides of pilosulin 1 were less efficient in causing loss of cell viability and the results suggest that the 22 N-terminal residues are critical to the cytotoxic activity of pilosulin 1. Normal blood white cells were also labile to pilosulin 1. T- and B-lymphocytes, monocytes and natural killer cells, however, were more labile than granulocytes. Analysis of pilosulin 1 using circular dichroism indicated that, in common with melittin and other Hymenoptera venom toxins, it had the potential to adopt an alpha-helical secondary structure.
authors.affiliation: Molecular Immunology, Kolling Institute of Medical Research, Royal North Shore Hospital, St. Leonards, NSW, Australia.
authors.forename: Q X
authors.initials: QX
authors.lastname: Wu
authors.forename: M A
authors.initials: MA
authors.lastname: King
authors.forename: G R
authors.initials: GR
authors.lastname: Donovan
authors.forename: D
authors.initials: D
authors.lastname: Alewood
authors.forename: P
authors.initials: P
authors.lastname: Alewood
authors.forename: W H
authors.initials: WH
authors.lastname: Sawyer
authors.forename: B A
authors.initials: BA
authors.lastname: Baldo
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000235:genetics / Q000633:toxicity*; D000595:Amino Acid Sequence; D000818:Animals; D000862:Ant Venoms / Q000737:chemistry / Q000235:genetics / Q000633:toxicity*; D001000:Ants; D001402:B-Lymphocytes / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002942:Circular Dichroism; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007962:Leukocytes / Q000187:drug effects; D007963:Leukocytes, Mononuclear / Q000187:drug effects; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary
chemical_list: D000485:Allergens; D000862:Ant Venoms; C079435:Myr p I; C115595:pilosulin 1