Synthesis and effect of shortened oostatic decapeptide (TMOF) analogs withisosteric structures on reproduction of Neobellieria bullata

Oligopeptides 2a-2d derived from the oostatic decapeptide (TMOF) sequence, H-Tyr-Asp-Pro-Ala-Pro-Pro-Pro-Pro-Pro-Pro-OH (la) and containing isosteric structures were synthesized and assayed to determine their effect during re production in the flesh fly Neobellieria bullata. The N-terminal linear tet ra-and pentapeptides Za, 2b containing the Pro-psi [CH2O]Ala isosteric link age affect egg development in 80-90% of ovarioles resulting in some resorbe d egg chambers, abnormal yolk deposition, the formation of large eggs with irregular yolk granules and proliferation of follicular epithelium. In comp arison with their nonisosteric precursors Ib, Ic they exhibit even more acc elerated oostatic activity. However, peptides 2c, 2d containing a Pro-psi [ CH2S]Ala isosteric linkage are less active.