Figure 2.

Induction of genes encoding antimicrobial peptides in third-instar larvae of different genotypes. Total RNA was extracted from heterozygous (dom/+) or homozygous domino (dom/dom) larvae that were submitted to various treatments, and 20 μg samples were analyzed by Northern blotting. Blots were hybridized successively with the following random-primed cDNA probes: Dipt, diptericin; Drom, drosomycin; CecA, cecropin A1; Metch, metchnikowin, and rp49. c: control unchallenged larvae. ci: larvae collected 6 h after clean injury. Ec + Ml, Ec, Ml, Bb: larvae collected 6 h after pricking with a needle coated with E. coli and M. luteus (Ec + Ml), E. coli alone (Ec), M. luteus alone (Ml), or spores of B. bassiana strain 80.2 (Bb). Bb nat: larvae collected 24 h after natural infection by spores of B. bassiana. This experiment was repeated three times and yielded similar results.