BIOSYNTHESIS, SECRETION, AND IMMUNOCYTOCHEMISTRY OF TRYPSIN MODULATING OOSTATIC FACTOR OF AEDES-AEGYPTI

Trypsin modulating oostatic factor (TMOF) was followed by RIA in the o vary of female Aedes aegypti before and after the blood meal. The amou nt of TMOF in a pair of ovaries from females fed sugar for 3 days or b lood for 24 h was low (1.7 ng). Between 24 and 48 h after the blood me al the amount of TMOF in the ovaries rapidly increased and reached a p eak of 104 ng at 48 h. The amount of TMOF in the head of a female A. a egypti was very low (0.05 to 0.1 ng) during sugar and blood feeding. I mmunocytochemical methodology identified the follicular epithelium as the site of biosynthesis of TMOF in the ovary. Females ovariectomized and fed a blood meal continued to synthesize trypsin for 64 h, whereas intact controls stopped at 40 h, indicating that a factor from the ov ary regulates trypsin biosynthesis. Ovaries incubated in vitro with [H -3]proline synthesized [pro-H-3]TMOF that was identified by HPLC and b y anti-TMOF serum. The ovary started to synthesize TMOF in vitro 24 h after the blood meal, and the synthesis reached a peak at 36 h and the n declined. The synthesis of TMOF by the ovary is closely correlated w ith the termination oi trypsin biosynthesis in the female mosquito's m idgut. Ovaries that were pulsed with [3H]proline for 30 min synthesize d [pro-H-3]TMOF which was chased into the medium with unlabeled prolin e, indicating that the hormone is secreted by the ovary. These results indicate that TMOF is a secretory peptide, synthesized by the ovarian follicular epithelium and that it modulates trypsin biosynthesis in t he mosquito's gut. (C) 1994 Wiley-Liss, Inc.