Submitted to: Ecdysone Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 22, 1996
Publication Date: N/A
Technical Abstract: One of the primary mechanisms inhibiting molting in baculovirus- infected insects is the apparent inactivation and possible elimination of the molting hormone, 20-hydroxyecdysone, and its precursor ecdysone, following sugar conjugation. Although host molting is similarly blocked in many host-parasite systems, no evidence for sugar conjugation of ecdysteroids has been forthcoming. We present, for the first time, evidence of sugar conjugation of ecdysteroids as a possible mechanism in preventing molting in T. ni, fourth-instar larvae fed on by E. plathypenae and E. comstockii. By combining high performance liquid chromatography, radioimmunoassay and enzymatic digestion of ecdysteroid glycosyl conjugates, we show that the major immunoreactive ecdysteroid (i. e., 85 % of the total hemolymph immunoreactivity) of 140-h parasitized larvae is primarily a conjugate of 20-hydroxyecdysone.