Ecdysteroid levels and pupariation in drosophila melanogaster

Abstract

Ecdysteroid t i t e r s measured i n t h e haemolymph o f t h i r d i n s t a r l a r v a e o f Drosophila revealed t h e existence o f a small peak (40 ng/ml) preceding t h e major peak a t p u p a r i a t i o n . Under experimental c o n d i t i o n s o f delayed p u p a r i a t i o n , t h e release o f b o t h e c d y s t e r o i d peaks i s retarded. t h e programming o f t h e t i m e o f p u p a r i a t i o n i s r a i s e d . The p o s s i b i l i t y t h a t t h e e a r l i e r pulse i s i m p l i c a t e d i n I t i s known t h a t p u p a r i a t i o n i n t h e D i p t e r a i s induced by ecdysteroids (Fraenkel, '34; Butenandt and Karlson, '54). Several authors have measured e c d y s t e r o i d l e v e l s i n Drosophila melanogaster (Borst e t a l . , '74; De Reggie t a l . , '75; Hodgetts e t a l . , ' 7 7 ) . We are i n v e s t i g a t i n g t h e programming o f p u p a r i a t i o n i n t h i s animal and our s t u d i e s have l e d us t o examine w i t h g r e a t e r p r e c i s i o n m o l t i n g hormone t i t e r s throughout t h e t h i r d l a r v a l i n s t a r and e a r l y pupal period. whole animals.(Porcheron e t a l . , '76) we have been a b l e t o measure t h e e c d y s t e r o i d l e v e l d i r e c t l y i n small volumes of haemolymph. E a r l i e r measures were performed on homogenates o f

Discrete pulses of molting hormone, 20‐hydroxyecdysone, during late larval development of Drosophila melanogaster: Correlations with changes in gene activity

“…antibody preparations used previously (see Richards, 1981;Berreur et al, 1979Berreur et al, , 1984Schwartz et al, 1984). Nevertheless, both the H22 and SHO3 antisera exhibit similar affinity to 20E.…”

“…Thus, it is not surprising that the published studies present ecdysteroid titers with different numbers and developmental timing (see Richards, 1981;Berreur et al, 1979Berreur et al, , 1984Schwartz et al, 1984;Parvy et al, 2005). The number, timing, and composition of low-amplitude elevations during the feeding stage of the last (third) larval instar are of importance because one or more may be analogous to the commitment peak of Lepidoptera (Bollenbacher et al, 1975;Riddiford, 1976;Wolfgang and Riddiford, 1986;Parlak et al, 1992;Dai et al, 1995).…”

Size and shape: the developmental regulation of static allometry in insects

“…The termination of growth is also caused by a rise in ecdysone levels. (17,18) However, the physiological mechanisms that link the attainment of critical size with this rise in ecdysone have not been elucidated in any insect other than M. sexta. Consequently, it is not clear that Drosophila has a delay that is mechanistically identical to the ICG of M. sexta.…”

The kinase Sgg modulates temporal development of macrochaetes inDrosophilaby phosphorylation of Scute and Pannier

“…One possibility is NFk-B/Rel, a factor that is required for functioning of the SOPE and singling out of precursors, and that also indirectly affects the 331 RESEARCH ARTICLE Phosphorylation of Scute by Sgg stability of sc transcripts (Culi and Modolell, 1998;Ayyar et al, 2007). Another event that coincides with the accumulation of acsc products at mid third larval instar is a small peak of 20H-ecdysteroid (not associated with a moult) (Berreur et al, 1979;Riddiford, 1993). Indeed ecdysone has been implicated in temporal regulation of expression of the proneural gene atonal and the development of atonal-dependent sense organs (Niwa et al, 2004).…”