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| Author(s): | Jarosz J. |
| Year: | 1998 |
| Title: | Active resistance of entomophagous rhabditid Heterorhabditis bacteriophora to insect immunity |
| Citation: | Parasitology. 117:(3) 201-208. . |
Abstract:
A specific extracellular proteinase, degrading selectively the cecropin-based defence system of insects, is secreted into the larval body during parasitism of the greater wax moth by the H. bacteriophora/Photorhabdus luminescens complex and by phase 1 of P. luminescens. The proteolytic digestion of insect inducible cecropin-like immune molecules was demonstrated by the disappearance of the Galleria mellonella cecropins and purified Hyalophora cecropin B peptide PAGE bands upon exposure to infected extracts, and a similar abrogation of antibacterial activity using an agar diffusion assay. Proteolytic activity of infected extracts produced by the nematode/bacterial complex and phase 1 variant of P. luminescens was shown to be correlated with cecropin-inhibitory activity, suggesting that this anti-cecropin agent may be responsible for the ability of bacteria to establish infection and the insecticidal nature of H. bacteriophora. Antibacterial activity of Galleria lysozyme and that of chicken egg-white lysozyme to which P. luminescens is insensitive, was unaffected by H. bacteriophora proteinase |
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