ملخص: The activity of RH-0345 (halofenozide), a novel benzoylhydrazine analogue, was investigated on ecdysteroid production, cuticle secretion, and hemolymph protein concentrations in Tenebrio molitor pupae. The compound was applied topically (5 and 10 [mu]g/pupa) on newly ecdysed pupae or added to the culture medium (1 and 10 [mu]M) of sternal integuments explanted from newly ecdysed pupae. Enzyme immunoassay measurements of ecdysteroid titers in the hemolymph revealed that RH-0345 applied topically on newly ecdysed pupae had no effect on the peak position of ecdysteroids in the hemolymph, but it caused a significant increase of the peak values. With in vitro cultured integument explants, RH-0345 caused a significant increase of the amounts of ecdysteroids released into the culture medium. Further, integuments were cultured in medium containing RH-0345 and/or 20-hydroxyecdysone (20E) and the effects on apolysis and cuticle growth were tested. In the presence of 20E alone, the epidermis was able to secrete a new cuticle under the apolyzed pupal cuticle. Similarly, integument explants from RH-0345-treated series cultured without 20E underwent apolysis and then secreted a new cuticle. The thickness of such a newly induced cuticle did not change as a function of the concentration of RH-0345 nor of the incubation period. In contrast, integument explants from RH-0345-treated series cultured in the presence of 20E secreted a new significantly thicker cuticle. The observed differences in cuticle thickness could be explained by differences in the protein content.

لغة: إنجليزية