EMSAs with A. culicifacies refractory (R) strain nuclear extract and 400 bp probes from upstream sequences of acsp30 of S and R strains. (A) EMSA showing the binding pattern of nuclear proteins extracted from body tissue of five-day old adult female R strain mosquitoes when incubated with S400 (lane 2) and R400 (lane 3) probes at 37°C for 25 minutes. Free probes were run in lane 1 (S400) and lane 4 (R400). (B) The radiolabelled probe R400 was incubated with refractory nuclear extracts without competitor (lane 3) and in the presence of unlabeled probe at 50-fold (lane 4) and 100-fold (lane 5) molar excess. Arrows indicate the migration of complex A (slow migrating) and B (fast migrating). The intensities of the signals were quantified with respect to Phospholmager signals by the Image Analysis Software, ImageQuant TL (Amersham Biosciences) and represented as the percentage ratio of S400 to R400 signal intensities (Fig. 8A) and as percentage ratio to the uncompeted (R400) signal intensities (Fig. 8B).