[The protein of the ejaculatory bulb (PEB) in Drosophila melanogaster. 1. Its stage specificity and sex dimorphism].

PEB is the major protein (35-39 kDa) of highly differentiated ejaculatory bulbs in D. melanogaster. A minor ejaculatory bulb protein (hPEB) of about 80 kDa was detected using immunoblotting technique. Both proteins exhibit parallel genetic variation in electrophoretic mobility. This suggests that they are coded by the same gene. The proteins are present in adult males and are not detected in virgin females. During development they are first detected in male pupa at the stage of eye pigmentation (that is shortly before imago eclosion). The quantities of PEB and hPEB increase and reach the constant level at 6-10 day of imago development.