Sequencing and characterization of trypsin modulating oostatic factor (TMOF) from the ovaries of the grey fleshfly, Neobellieria (Sarcophaga) bullata.

Injection of crude extracts of late vitellogenic ovaries into staged females of the grey fleshfly Neobellieria (Sarcophaga) bullata inhibited oocyte development and biosynthesis of trypsin-like enzymes in the gut. Trypsin synthesis in N. bullata is cyclic and is correlated with egg development, which is discontinuous. A trypsin modulating oostatic factor (Neb-TMOF) was purified from 10,000 vitellogenic ovaries and sequenced by mass spectrometry. Neb-TMOF is a hexapeptide (NH2-NPTNLH-COOH). 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 the hemolymph and of oocyte growth. The role of Neb-TMOF in controlling egg development and the physiological similarities with Aedes-TMOF are discussed.