INDUCTION OF CECROPIN-LIKE AND ATTACIN-LIKE ANTIBACTERIAL BUT NOT ANTIVIRAL ACTIVITY IN HELIOTHIS-VIRESCENS LARVAE

Inducible cecropin-like and attacin-like proteins were isolated from i mmune hemolymph obtained from vaccinated Heliothis virescens larvae. T he attacin-like protein had a molecular weight of approximately 25,000 daltons and was not dialyzable. The cecropin-like peptide had an esti mated molecular weight of 6,000-7,000 daltons and was dialyzable, heat -stable and sensitive to trypsin digestion. The cecropin-like peptide showed bactericidal activity against Escherichia coli and Enterobacter cloacae, and the attacin-like protein showed bactericidal activity ag ainst E. coli. The immune hemolymph was bactericidal against E. coli, E. cloacae and Pseudomonas aeruginosa. Ultrastructural cell envelope d amage to E. coil, produced by the immune hemolymph, was observed by sc anning electron microscopy. No antiviral activity by the inducible cec ropin-like and attacin-like proteins was detected against herpes simpl ex virus-1 and the vesicular stomatitis virus. (C) 1994 Academic Press , Inc.