SEQUENCING AND CHARACTERIZATION OF TRYPSIN MODULATING OOSTATIC FACTOR(TMOF) FROM THE OVARIES OF THE GRAY FLESHFLY, NEOBELLIERIA (SARCOPHAGA) BULLATA

Injection of crude extracts of late vitellogenic ovaries into staged f emales of the grey fleshfly Neobellieria (Sarcophaga) bullata inhibite d oocyte development and biosynthesis of trypsin-like enzymes in the g ut. Trypsin synthesis in N. bullata is cyclic and is correlated with e gg development, which is discontinuous. A trypsin modulating oostatic factor (Neb-TMOF) was purified from 10,000 vitellogenic ovaries and se quenced by mass spectrometry. Neb-TMOF is a hexapeptide (NH2-NPTNLH-CO OH). Injection of the hormone at physiological concentrations (10(-9) M), inhibited trypsin-like synthesis by the midgut of liver-fed female flies, and caused a reduction of the vitellogenin concentration in th e hemolymph and of oocyte growth. The role of Neb-TMOF in controlling egg development and the physiological similarities with Aedes-TMOF are discussed.