Location: Chemistry Research Unit
Title: Identification of methyl farnesoate from hemolymph of insects Authors
|Jones, Davy -|
|Jones, Grace -|
|Torto, Baldwyn -|
|Nyasembe, Vincent -|
|Borgemister, Christian -|
|Boucias, Drion -|
|Lietze, Verena -|
Submitted to: Journal of Natural Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 9, 2014
Publication Date: N/A
Interpretive Summary: Until recently methyl farnesoate, methyl-(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trienoate (MF), was not been thought to have any physiological function in insects although it is the immediate biosynthetic precursor of the insect hormone Juvenile hormone III (methyl-(2E,6E)-10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate). However, recently MF was both identified from hemolymph and shown to have physiological functions in Drosophila melanogaster. We identified MF from circulating hemolymph obtained from five different orders of insects representing holometabolous and hemimetabolus groups. The identification of MF from the American bird grasshopper (order Orthoptera) was facilitated using both electron and chemical ionization GC-MS, GC-FTIR and 2D NMR techniques. Identifications from other insects (Diptera, Hymenoptera, Coleoptera and Hemiptera) were made using GC-MS (EI and CI) and amounts from all insects were quantified using LIM-CI-GC-MS. The ratios of JH III and MF varied in these insects during different developmental stages, thus, these results underscore the need for further studies on MF as a circulating hormone in insects.
Technical Abstract: Juvenile hormones (JH) have been a focal point of study in insect endocrinology for more than 80 years and are implicated in regulation of more physiological and behavioral functions than any other insect hormone. Indeed, evidence has suggested that JHs are the only sesquiterpene hormone products secreted by the corpora allata into and carried by the insect hemolymph. We report here the chemical identification, from insect hemolymph, of methyl farnesoate (MF), the immediate biosynthetic precursor to JH III in insects, and the same hormone that circulates in the more primitive crustaceans. We have identified MF in hemolymph from five orders of insects: Orthoptera, Diptera, Homoptera, Coleoptera, and Hymenoptera, and from both adult and immature insects. Larval fruit flies (Drosophila melanogaster) contained up to ten times higher MF titer than JH III, and in adult worker Honeybees (Apis mellifera) the MF titer was correlated with vitellogenin transcription, but JH titers were not. We also demonstrated functionally distinct activities of MF and JH III in an adult primitive insect, the desert locust (Schistocerca gregaria). Whereas application of a JH analog (methoprene) rescued both the color phase change and production of the aggregation pheromone in males that were all chemically blocked for JH production, MF application did not rescue these events. Indeed, MF application suppressed or prevented methoprene from rescuing male color change or pheromone release. The facts that MF (a) exists in the hemolymph of a wide variety of primitive and higher insect orders, often at concentrations greatly exceeding JH III, (b) has biological activities distinct from JH III, and (c) serves some of the same functions in crustaceans as are attributed to JH in insects, all underscore the need for further studies on MF as an insect hormone.