0000000000586348
AUTHOR
Nicole Pitoizet
2-Deoxyecdysone is a circulating ecdysteroid in the beetle Zophobas atratus
A qualitative analysis of ecdysteroids has been performed during the post-embryonic development of the tenebrionid beetle, Zophobas atratus, by high performance liquid chromatography (HPLC) combined with enzyme immunoassay (EIA) using two different antibodies. Three HPLC peaks were found to be immunoreactive, in hemolymph extracts of both sexes. Moreover, these peaks had ecdysteroid-like UV spectra, determined using a photodiode array detector. The use of two different HPLC systems (reverse and normal phases), in combination with two different EIA antibodies, allowed us to identify 20-hydroxyecdysone (20E) and ecdysone (E), as the two main ecdysteroids, but also suggested the presence of 2-…
Ecdysteroid titres in a tenebrionid beetle, Zophobas atratus: effects of grouping and isolation.
Metamorphosis in Zophobas atratus is dependent on isolation: when kept in grouped conditions, larvae undergo numerous supernumerary moults, growing in size, without pupating. This beetle thus represents an interesting model for the analysis of possible differences in the endocrine regulation of normal vs. supernumerary larval moults. In this study, the ecdysteroid titres have been analysed in this species, using enzyme immunoassay. The hormonal variations of larvae undergoing normal or supernumerary larval cycles were particularly examined, in either grouped or isolated conditions. Normal larval cycles presented very similar ecdysteroid variations in grouped as well as isolated conditions, …
Evolution of ecdysteroids and of their apolar conjugates during the post-embryonic development of the tickOrnithodoros moubata
The ecdysteroid (ES) content of the soft tick Ornithodoros moubata was investigated during the five successive nymphal molting cycles by means of an enzyme immunoassay (EIA). Samples were submitted to esterase hydrolysis in order to release free ecdysteroids from the acyl-ester conjugates (AP = apolar products). Crude and hydrolysed extracts were then analyzed by EIA using two different antibodies, a monoclonal raised against 20-hydroxyecdysone (20E) and a polychlonal raised against ecdysone (E). With the crude extracts, each molting cycle was associated with an ES peak, occurring in the middle of the instar. 20E was preponderant during the first 2 nymph cycles, but the proportion of E and …
Effects of the ingestion ofSerratula tinctoria extracts, a plant containing phytoecdysteroids, on the development of the vineyard pestLobesia botrana (Lepidoptera: Tortricidae)
We describe here the effects of extracts from Serratula tinctoria, a plant producing phytoecdysteroids, on the growth and development of Lobesia botrana, an economically important pest in vineyards. Leaves, hairy roots, or semi-purified (by Sep-Pak procedure) methanolic extracts from this plant were incorporated into an artificial diet given to insects. Larval growth, mortality, weight, and sex-ratio were investigated, as well as sterol and ecdysteroid contents. Experimental diets induced an important mortality in the first, second, and third larval instars, but also in pupae. As males appeared more sensitive to extracts, sex ratio was significantly modified on experimental diets (particula…
Synthesis and gas chromatographic-mass spectrometric analysis of reduced compounds derived from 6 alpha- and 6 beta-hydroxy-11-deoxycorticosterone.
Abstract A series of thirty two 6-hydroxylated steroids were synthesized by selective reduction of the 4–5 double bond, the 3-oxo group, and/or the 20-oxo group of 6α- and 6β-hydroxyDOC. The different reactions leading to the production of specific isomers are discussed. The gas chromatographic and spectrometric characteristics of the methoxime-trimethylsilyl (MO-TMS) or trimethylsilyl (TMS) derivatives of the isomers obtained are given. The gas chromatographic separation of the syn- and anti -isomers of the methoxime in position 3 was found to be characteristic of the configuration of the hydroxyl in position 6. The difference between methylene unit values of syn- and anti- isomers is much…