How many genetic options for evolving insecticide resistance in heliothine and spodopteran pests?

The widely accepted paradigm for the development of insecticide resistance in field populations of insects is of selection for one or a very few genes of major effect. Limited genetic mapping data for organophosphate and pyrethroid resistance in heliothine and spodopteran pests generally agrees with this paradigm. However, other biochemical and transcriptomic data suggest a more complex set of changes in multiple P450 and esterase gene/enzyme systems in resistant strains of these species.

A peptidomics study reveals the impressive antimicrobial peptide arsenal of the wax moth Galleria mellonella.

The complete antimicrobial peptide repertoire of Galleria mellonella was investigated for the first time by LC/MS. Combining data from separate trypsin, Glu-C and Asp-N digests of immune hemolymph allowed detection of 18 known or putative G. mellonella antimicrobial peptides or proteins, namely lysozyme, moricin-like peptides (5), cecropins (2), gloverin, Gm proline-rich peptide 1, Gm proline-rich peptide 2, Gm anionic peptide 1 (P1-like), Gm anionic peptide 2, galiomicin, gallerimycin, inducible serine protease inhibitor 2, 6tox and heliocin-like peptide.

Proteomic analysis of the peritrophic matrix from the gut of the caterpillar, Helicoverpa armigera.

The peritrophic matrix from the midgut of the caterpillar, Helicovera armigera, was solubilized by treatment with anhydrous trifluoromethanesulfonic acid, apparently by depolymerisation of its chitin component. This allowed the efficient extraction of proteins in a technique that may be broadly applicable to the analysis of other structures containing chitin. Gel electrophoresis and mass spectrometry of tryptic peptides were used to identify the extracted proteins with gut-expressed cDNA sequences.

The discovery and analysis of a diverged family of novel antifungal moricin-like peptides in the wax moth Galleria mellonella.

Screening for components with antifungal activity in the hemolymph of immune-stimulated Galleria mellonella larvae led to the identification of four novel moricin-like peptides (A, B, C3 and D). Subsequently, eight moricin-like peptide genes (A, B, C1-5 and D) were isolated and shown to code for seven unique peptides (mature C4 and C5 are identical). These genes contained single introns which varied from 180 to 1090bp.

A novel secreted protein toxin from the insect pathogenic bacterium Xenorhabdus nematophila.

The bacterium Xenorhabdus nematophila is an insect pathogen that produces several proteins that enable it to kill insects. Screening of a cosmid library constructed from X. nematophila strain A24 identified a gene that encoded a novel protein that was toxic to insects.