Figure 4. Effect of irradiation (350 nm for 20 min) in the presence/absence of ecdysteroid dienones (5: dacryhainansterone, 6: kaladasterone and 7: 25-hydroxydacryhainansterone; each at 100 nM) on the capacity of DmEcR/DmUSP (A) and CfEcR/CfUSP (B) ecdysteroid receptor complexes subsequently to bind [3H]ponasterone A specifically. Solid bars - UV + [3H]ponasterone A; shaded bars - no UV + [3H]ponasterone A; open bars - no UV + [3H] ponasterone A + a 250-fold excess unlabelled ponasterone A. Results shown are the mean values of duplicate samples; variation between replicates is 7% or less.