Abstract
The sex pheromone of Bombyx mori, bombykol [(10E, 12Z)-10, 12-hexadecadien-1-ol], can be biosynthesized in four steps: construction of a hexadecanoic moiety from acetyl CoA, Δ-11-desaturation, Δ-10, 12-desaturation, and reduction of the acyl group. This biosynthesis is regulated by a hormone named the pheromone biosynthesis activating neuropeptide (PBAN). To examine the steps that are accelerated by this neurohormone, pheromone glands excised from decapitated females were incubated in vitro with either 14C-labeled sodium acetate or one of three fatty acids [hexadecanoic acid, (Z)-11-hexadecenoic acid, or (10E, 12Z)-10, 12-hexadecadienoic acid]. After analyzing the radioactivity that was incorporated from each precursor into bombykol and the biosynthetic precursors, it was observed that the first three steps proceeded in glands both treated and untreated with synthetic PBAN of B. mori; however, the last step proceeded only in the treated glands. From this in vitro experiment, it can be concluded that the main regulatory role of PBAN is in the reduction of the acyl group in B. mori, as was shown by our previous in vivo experiment.
