Ecdysteroid 7,9(11)-dien-6-ones as potential photoaffinity labels for ecdysteroid binding proteins

Abstract

Three ecdysteroid 7,9(11)-dien-7-ones (dacryhainansterone, 25-hydroxydacryhainansterone and kaladasterone) were prepared by dehydration of the corresponding 11a-hydroxy ecdysteroids (ajugasterone C, turkesterone and muristerone A, respectively). The biological activities of the dienones in the Drosophila melanogaster B II cell bioassay, which reflect the affinity for the ecdysteroid receptor complex, showed that the dienones retain high biological activity. Irradiation at 350 nm of the ecdysteroid dienones (100 nM) with bacterially-expressed dipteran and lepidopteran ecdysteroid receptor proteins (DmEcR/DmUSP or CfEcR/CfUSP), followed by loading with [ 3 H]ponasterone A revealed that irradiation of dacryhainansterone or kaladasterone resulted in blocking of >70% of the specific binding sites. Thus, ecdysteroid dienones show considerable potential as photoaffinity analogues for ecdysteroid binding proteins.

Sex Pheromone Evolution Is Associated with Differential Regulation of the Same Desaturase Gene in Two Genera of Leafroller Moths

“…While desat2 from C. obliquana and C. herana have no activity on typical sex pheromone fatty acid precursors, similar to desaturases identified previously from Choristoneura rosaceana and Ch. parallela [38] , [43] , we identified two desaturases showing interesting activities: desat3 and desat4. Desat3 from P. excessana encodes a desaturase with terminal desaturase activity, an activity that has recently been implicated in pheromone biosynthesis in the winter moth, Operophtera brumata [40] .…”

“…Moreover, some Ctenopseustis and Planotortrix desaturases group closely with previously characterized desaturases from other species. First, the Ctenopseustis and Planotortrix desat2 orthologs group closely with a non-functional desaturase from Choristoneura rosaceana [38] ; second, the desat6 orthologs group with a Δ9-desaturase from Epiphyas postvittana [39] ; and third, even though less closely related, desat3 groups with a terminal desaturase from Operophtera brumata [40] . Finally, the six predicted desaturases from Ctenopseustis and Planotortrix are all well separated from each other in the phylogenetic tree, with many other lepidopteran desaturases inter-dispersed between them.…”

“…Two of the six desaturases from Ctenopseustis and Planotortrix encode Δ9-desaturases ( desat1 and desat6 ) that display highly conserved functions across all lepidopteran insects investigated to date [17] , [19] , [37] , [38] , [39] , [42] . For example, desat6 from C. obliquana and its ortholog from E. postvittana (Epo-Z9 ) encode a Δ9-desaturase with a preference for 18 carbon fatty acid precursors over 16 carbon precursors [39] .…”

“…desat2 orthologs) from Choristoneura spp. [38] , [43] or Z11-desaturases from Helicoverpa spp. [42] , [44] .…”

“…Only in the case of Choristoneura parallela and Ch. rosaceana did two Δ11-orthologs that shared 92% protein identity differed slightly in activity, producing E11-14:acid or a mixture of Z/E11-14:acids, respectively [38] , [43] . Still both enzymes introduced double bonds at the 11 th carbon position, only differing in their isomeric preference.…”