Physiological status and change of cytoplasmic lipid droplets in the pheromone-producing cells of the silkmoth, Bombyx mori (Lepidoptera, Bombycidae)

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

“…In B. mori, PBAN directly acts on the pheromone gland to stimulate bombykol production (8,24). 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).…”

“…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).…”

“…In the silkmoth, Bombyx mori, the pheromone gland located between the eighth and ninth abdominal segments initiates production of the sex pheromone bombykol, (E,Z)-10,12-hexadecadien-1-ol, during photophase starting from the day of adult eclosion (4,5). Bombykol is synthesized de novo from acetyl-CoA through palmitate (16:Acyl), which is stepwise converted to bombykol by ⌬11 desaturation, ⌬10,12 desaturation, and fatty-acyl reduction (2,6).…”

Identification of Functionally Important Residues of the Silkmoth Pheromone Biosynthesis-activating Neuropeptide Receptor, an Insect Ortholog of the Vertebrate Neuromedin U Receptor

“…They are synthesized de novo in the pheromone gland (specialized tissue located between the 8th and 9th abdominal segments) from acetyl-CoA through fatty acid synthesis with varied desaturation and limited chain-shortening reactions followed by reductive modification of the acyl group (2,3). In the silkmoth, Bombyx mori, production of the principal sex pheromone component bombykol, (E,Z)-10,12-hexadecadien-1-ol, is initiated during photophase starting from the day of adult eclosion (4,5). Like most moth sex pheromones, bombykol is synthesized from acetyl-CoA through palmitate (16:0) but is then stepwise converted to the bioactive compound by ⌬11 desaturation, ⌬10,12 desaturation, and fatty acyl reduction to the alcohol (2, 6 -8).…”

“…The PBAN receptor (PBANR) was first cloned from H. zea (20) as an ortholog of the vertebrate neuromedin U receptor (NMUR) (21)(22)(23)(24), which recognizes peptides with a C-terminal FRPRN-NH 2 motif such as neuromedin U (NMU) and neuromedin S (25,26). Since then, PBANRs from B. mori (27), Heliothis virescens (28), Manduca sexta (GenBank TM accession numbers FJ240221 to FJ240224), 5 Plutella xylostella (29), Helicoverpa armigera (30), Spodoptera littoralis (31), Spotoptera exigua (32), Pseudaletia separata (33), and Ostrinia nubilalis (34) have been identified. Functional analyses have shown that PBANR activation triggers an influx of extracellular Ca 2ϩ in isolated B. mori pheromone glands (35) as well as insect cells transiently expressing PBANR (20,27).…”