Compared activity of agonist molecules towards ecdysone receptor in insect cell-based screening system

ABSTRACT: The ecdysone receptor, naturally activated by steroidal hormones, is a key protein for molting and reproduction processes of insects. Artificial activation of such receptor by specific pesticides induces an anomalous process of ecdysis, causing death of insects by desiccation and starvation. In this paper, we established a protocol for screening agonistic molecules towards ecdysone receptor of insect cells line S2 (Diptera) and Sf9 (Lepidoptera), transfected with the reporter plasmid ere.b.act.luc. Therefore, we set dose-response curves with the ecdysteroid 20-hydroxyecdysone, the phytoecdysteroid ponasterone-A, and tebufenozide, a pesticide belonging to the class of diacylhydrazines. In both cell lines, the median effective concentration values on reporter gene induction (EC50) of ponasterone-A was the smallest, meaning the most active agonist molecule. In Sf9 cells, tebufenozide had as smaller EC50 than 20-hydroxyecdysone, indicating the high agonistic capability and lepidopteran specificity. The protocol established in this study can be useful for a quick screening and rational research of site-specific pesticides.

Efficient synthesis of ponasterone A by recombinant Escherichia coli harboring the glycosyltransferase GTBP1with in situ product removal

A glycosyltransferase GTBP1fromBacillus pumilusBF1 was isolated.

Ecdysteroid Profiles of Two Ajuga species, A. iva and A. remota

Phytoecdysteroids are plant analogues of insect moulting hormones and are used by plants to repel or disturb phytophagous insects. They are also active on mammals and present in many plants used in traditional medicine. The Ajuga genus contains several such species, which occur in various pharmacopoeias. We report the isolation and identification of major and minor ecdysteroids present in two Ajuga species, A. iva and A. remota, both of which are used as medicinal plants in Africa. Three minor ecdysteroids (abutasterone, ponasterone A and sidisterone) have been found for the first time in the Ajuga genus.

Novel Ecdysteroids fromSerratula wolffii

Two new and one known ecdysteroids were identified in the methanolic extract of the roots ofSerratula wolffii. The new compounds isolated were ponasterone A-22-apioside (1) and 3-epi-shidasterone (3), together with the known 3-epi-22-deoxy-20-hydroxyecdysone (2). The structures of compounds1–3were determined by extensive spectroscopic techniques, including one- and two-dimensional NMR methods.