Control of the pheromone biosynthetic pathway in Helicoverpa zea by the pheromone biosynthesis activating neuropeptide

Abstract

Hormonal control of the production of the main sex pheromone component, Z11-hexadecenal (Z11-16:Ald), of female Helicoverpa zea was investigated using labeled precursors to monitor the pheromone biosynthetic pathway. The pathway originates with the biosynthesis of palmitic acid followed by A11 desaturation to form the intermediate Z11-16:Acid, which is then reduced to a primary alcohol and then oxidized to Z11-16:Ald. Incubation of glands either in vivo or in an isolated gland culture with the deuterium labeled compounds, D3-16:Acid or D9-Z11-16:Acid, yielded no differences in label incorporation into pheromone in the presence or absence of synthetic PBAN (Pheromone biosynthesis activity neuropeptide). However, unlabeled pheromone titers increased about tenfold above controls in the presence of PBAN in both in vivo and in vitro cultures. When isolated glands were incubated with [1-'4Clacetate, about a thirtyfold increase in the incorporation of radiolabel into Z11-16:Ald above controls was observed in the presence of PBAN. Also, about a tenfold increase in incorporation was observed in saturated and monounsaturated fatty acids found in the gland upon stimulation with PBAN. These results indicate that the hormone PBAN controls pheromone biosynthesis in H. zea by regulating a step in or prior to fatty acid biosynthesis.

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

“…6,12) In heliothine moths, however, PBAN regulates a step (most likely acetyl-CoA carboxylase) in fatty acid biosynthesis. [13][14][15] (iii) In B. mori, the cyclic nucleotide second messenger, cyclic adenosine-3 0 ,5 0 -monophosphate (cAMP), is not involved in the PBAN signal transduction cascade, 16) whereas in heliothine species, the second messenger is a crucial component in PBAN signaling. 4,8) Because numerous biological processes are mediated by fluctuations in the intracellular levels of Ca 2þ , the entry of Ca 2þ into the cell is tightly regulated.…”

Stimulation of pheromone biosynthesis in the moth Helicoverpa zea: action of a brain hormone on pheromone glands involves Ca2+ and cAMP as second messengers.

“…Although the exact site of PBAN action has not been conclusively determined for any one species, recent reports indicate that PBAN stimulates [14C]acetate incorporation into pheromone by isolated pheromone glands of Helicoverpa armigera and H. zea (17)(18)(19)(20). This activity is apparently mediated by the second messenger cAMP (21).…”

“…H. zea were maintained at 26 ± 20C with a light:dark cycle of 16:8 hr. Larvae and adults were maintained as reported previously (20). Females in their third or fourth photophase were used throughout this study.…”

“…Isolated glands were prepared as described previously (20). One gland per 5 ,ud of saline was utilized throughout this study.…”

Molecular Mechanisms Underlying Sex Pheromone Production in Moths

“…20) In heliothine moths, however, PBAN regulates a step (most likely acetyl-CoA carboxylase) in fatty acid biosynthesis. [76][77][78][79] (iii) In B. mori, the cyclic nucleotide second messenger, cyclic adenosine-3 0 ,5 0 -monophosphate (cAMP), is not involved in the PBAN signal transduction cascade, 80) whereas in heliothine species the second messenger is a crucial component in PBAN signaling. 58,59) …”