title: Purification and characterization of insecticidal toxins from venom glands of the parasitic wasp, Bracon hebetor.
abstract: The potency of venom from Bracon hebetor against lepidopterous larvae has been known for over 40 years, but previous attempts to purify and characterize individual protein toxins have been largely unsuccessful. Three protein toxins were purified from venom of this small parasitic wasp and the amino acid sequences of 22-31 consecutive residues at the amino-terminus were determined. These relatively large toxins (apparent molecular mass 73 kDa) were labile under many isolation techniques, but anion-exchange chromatography allowed purification with retention of biological activity. Two purified toxins were quite insecticidal (LD50 < 0.3 microgram/g) when injected into six species of lepidopterous larvae. On a molar basis, one toxin (Brh-I) has the highest known biocidal activity against Heliothis virescens (LD50 = 2 pmol/g).
authors.affiliation: Sandoz Agro Inc., Palo Alto, CA 94304.
authors.forename: G B
authors.initials: GB
authors.lastname: Quistad
authors.forename: Q
authors.initials: Q
authors.lastname: Nguyen
authors.forename: P
authors.initials: P
authors.lastname: Bernasconi
authors.forename: D J
authors.initials: DJ
authors.lastname: Leisy
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007306:Insecticides / Q000302:isolation & purification*; D007814:Larva; D008969:Molecular Sequence Data; D009036:Moths; D010271:Parasites; D014862:Wasp Venoms / Q000737:chemistry*; D014863:Wasps
chemical_list: D007306:Insecticides; D014862:Wasp Venoms