ISSN:
0739-4462
Keywords:
Rhodnius prolixus
;
precocious metamorphosis
;
ecdysial stasis
;
juvenile hormones
;
precocene
;
prothoracic glands
;
regulation of ecdysone synthesis
;
Chemistry
;
Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Rhodnius prolixus nymphs fed 7-ethoxy-6-methoxy-2,2-dimethylchromene (ethoxyprecocene II, EPII) show a variety of responses, including precocious molting to diminutive adults, severe retardation of molting, or a condition of permanent ecdysial stasis. The latter two conditions are reversible by subsequent treatment with 20-hydroxyecdysone. Ecdysteroid titers in the hemolymph of individual insects, determined by radioimmunoassay (RIA), show that the ecdysteroid cycle in nymphs undergoing precocious metamorphosis is similar to that of untreated fifth stage nymphs during normal imaginal molting. Nymphs in ecdysial stasis, following EPII treatment, were found to have very low ecdysteroid titers. Analysis of ecdysteroid synthesis by the prothoracic glands (PG), cultured in vitro, showed that: 1) only traces of ecdysteroid were detectable in PG from nymphs treated in vivo with EPII; 2) the PG from untreated nymphs incubated in culture medium with EPII possessed significantly lower ecdysteroid synthesis compared with controls. These studies sought to determine if the inhibition of ecdysteroid biosynthesis observed in Rhodnius, following exposure to EPII in vivo and in vitro, is due to a direct action on the PG or result as an indirect effect perhaps mediated by the neuroendocrine system.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/arch.940080206
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