PURIFICATION OF ADULT DROSOPHILA-MELANOGASTER LIPOPHORIN AND ITS ROLEIN HYDROCARBON TRANSPORT

Lipophorin was isolated from homogenized adult Drosophila melanogaster . It is stained by Sudan Black and has a native molecular mass of 640 kD and a density of 1.12 g/ml. It consists of two glycosylated apoprot eins of 240 and 75 kDa. Cas chromatography and mass spectrometry showe d that lipophorins isolated separately from virgin 3-day-old male and female flies were associated with specific hydrocarbons, and that thes e were the same hydrocarbons found in male and female cuticles, respec tively. Moreover, a pool of internal hydrocarbons was demonstrated for the first time, with chain lengths similar to those of the cuticular pool. Studies on the fate of the hydrocarbons synthesized de novo afte r topical applications of radiolabelled fatty acid precursors showed a decrease of the internal pool of hydrocarbons with time, concomitant with an increase of the cuticular pool. These results suggest that hyd rocarbons synthesized at an internal site, possibly in oenocytes, may be transported to the cuticle of the flies by lipophorin. (C) 1996 Wil ey-Liss, Inc.