Sex pheromone biosynthesis from radiolabeled fatty acids in the redbanded leafroller moth

Radiolabeled fatty acids in dimethyl sulfoxide were applied topically to sex pheromone glands of young adult female Argyrotaenia velutinana. Glands treated with sodium [1-14C]acetate incorporated radiolabel into the sex pheromone components and into dodecanoic, tetradecanoic, hexadecanoic, octadecanoic, (Z)-11-tetradecenoic, and (E)-11-tetradecenoic fatty acyl moieties. In contrast, very little radiolabel was incorporated into unsaturated 18-carbon fatty acyl moieties and almost none into unsaturated 18-carbon fatty acyl moieties, although these moieties were abundant in the gland. A similar pattern of incorporation was observed for glands treated with [U-14C]hexadecanoic acid. In glands treated with [1-14C]hexadecanoic acid, a smaller proportion of the label was incorporated into the 14-carbon fatty acyl moieties than in glands treated with [U-14C]hexadecanoic acid, indicating that 14-carbon fatty acyl moieties arose from chain-shortening of hexadecanoyl moieties. In glands treated with [1-14C]tetradecanoic acid, (Z)-11-tetradecenoyl and (E)-11-tetradecenoyl moieties incorporated the most label, implicating (Z)-11 and (E)-11 desaturases specific for the tetradecanoyl chain. In glands treated with (Z)-11-[1-14C]tetradecenoic acid or (E)-11-[1-14C]tetradecenoic acid, very little label was incorporated into the other geometric isomer, implying that Z/E isomerases do not occur in the gland. In glands treated with (E)-11-[1-14C]tetradecenoic acid, much more label was incorporated into (E)-11-tetradecenyl acetate than with the other substrates, showing that most of the labeled acetate arose from reduction and acetylation of the labeled fatty acyl moiety.