Chemical characterization of cytoplasmic lipid droplets in the pheromone-producing cells of the silkmoth, Bombyx mori

Pheromone gland-specific fatty-acyl reductase of the silkmoth, Bombyx mori

“…Because bombykol production occurs shortly after adult eclosion in response to PBAN (5,24), the pheromone-producing cells must be primed for pheromone production upon adult eclosion. Consequently, there is a rapid accumulation of a large number of lipid droplets in the cytoplasm 1 day before adult eclosion (5,25), the function of which is to store the bombykol precursor fatty acid in the form of triacylglycerols (TG) (26). Lipolysis of the TG takes place upon adult eclosion, resulting in liberation of the bombykol precursor fatty acid, which is further reduced to bombykol via the fatty acyl-CoA intermediate (27).…”

Sex Pheromone Production in the Silkworm,Bombyx mori, Is Mediated by Store-Operated Ca2+Channels

“…6,25,33) Hence, we used PGs prepared from females decapitated 24 h prior to the onset of the experiment to explore further the role of extracellular Ca 2þ by examining the effects of various Ca 2þ channel blockers on PBAN-induced lipolysis. When stained with the fluorescent lipid marker, Nile Red, numerous large droplets were seen permeating the PGs were pre-incubated for 30 min in the presence of 100 mM verapamil, 100 mM nifedipine, 50 mM 2APB, or 50 mM SKF-96365, and then incubated 90 min in the presence of inhibitors + 120 nM PBAN.…”

Molecular Mechanisms Underlying Sex Pheromone Production in Moths

“…HPLC separation of the LD contents and mass-spectrometric structure analyses (FAB-MS and MS-MS) confirmed that they are various triacylglycerols (TAGs) with the bombykol precursor, Á10,12-hexadecadienoate, predominantly sequestered as a major component at the sn-1 and/or sn-3 position of the glycerides. 19) These results indicate that the LDs do indeed play a role in storing the bombykol precursor in the form of TAGs and in releasing it for bombykol production in response to PBAN stimulus. It has been found in B. mori that PBAN stimulates fatty acyl reduction, the final step in bombykol biosynthesis.…”

“…These results further confirmed that the PBAN signal stimulates liberation of the bombykol precursor from LDs. 17,19) V. Other Functional Molecules Involved in Pheromone Production…”

“…We have confirmed that fatty acyls sequestered in the TAGs are restricted to five long-chain fatty acyls: two unsaturated C 16 fatty acyls (Á11-hexadecenoate and Á10,12-hexadecadienoate) and three conventional C 18 fatty acyls (oleate, linoleate, and linolenate) with the bombykol precursor, Á10,12-hexadecadienoate, as a major component. 19) The bombykol biosynthesis precursors, Á11-hexadecenoate and Á10,12-hexadecadienoate, are synthesized de novo in PG cells. 13) In contrast, since linoleic and linolenic acids are essential fatty acids also in insects, 48) the conventional C 18 fatty acyls are basically derived from dietary fatty acids and must be taken up across the plasma membrane.…”