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Rearing and Injection of Manduca sexta Larvae to Assess Bacterial Virulence
Published on: December 11, 2012
A gloverin-like antibacterial protein is synthesized in Helicoverpa armigera following bacterial challenge
J A Mackintosh1, A A Gooley, P H Karuso
1School of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia. jmackint@rna.bio.mq.edu.au
Abstract:
A bacteria inducible antibacterial protein, P2, was isolated from the old world bollworm Helicoverpa armigera. Fifth-instar larvae were injected with live Escherichia coli NCTC 8196. P2 was isolated by HPLC using reversed-phase and size-exclusion columns. In addition, P2 was isolated by an alternative method of sequential cation-exchange and reversed-phase HPLC. The structure of P2 was determined by N-terminal Edman degradation and mass spectrometry. P2 had similar mass (14.1 kDa) structure and activity to gloverin, an inducible glycine-rich antibacterial protein isolated from Hyalophora gloveri [Axén, A.; Carlsson, A.; Engström, A.; Bennich, H. Eur. J. Biochem. 247:614-619; 1997]. At the N-terminus P2 had approximately 60% identity with gloverin. P2 is basic, heat stable, and displayed rapid antibacterial action. P2 was active against the Gram-negative bacteria tested and was inactive against the Gram-positive bacteria, Candida albicans, a bovine turbinate cell line, and pestivirus.
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