Electrophoretic protein patterns and esterase zymograms in ovaries and mature eggs of Bombyx mori in relation to diapause

Abstract

Starch-gel zone electrophoresis was performed on proteins of pharate adult and emerged adult ovaries, and in mature eggs in adults, in order to ascertain the mode of action of the diapause hormone on protein metabolism in the silkworm, Bombyx mori. Many protein bands were displayed characteristically by the developing ovaries and mature eggs of the silkworm races used. Among these bands, only one was affected by the diapause hormone. That is, the protein band is intensive in ovaries and mature eggs of the non-diapause type, but weak in those of the diapause type. This band was named band S, migrating positively with a mobility similar to albumin. Non-specific esterase activities were also tested in pharate adult and emerged adult ovaries and in mature eggs in adults. Esterase bands were detected individually for each species used. Among these bands, one esterase band was very active in ovaries and mature eggs of the non-diapause type but weak in those of the diapause type or those inactivated by the diapause hormone. This esterase was named esterase A. A comparison was carried out between protein band S and esterase A as regards progression with time during pharate adult development, both with response to the suboesophageal ganglion and diapause hormone extracts and with electrophoretic mobility. Subsequently, it was suggested that band S possesses proteins including esterase A. This particular protein with esterase A activity is discussed from the standpoint of embryogeny.