title: 20-Hydroxyecdysone and juvenile hormone regulate the laminarin-induced nodulation reaction in larvae of the flesh fly, Neobellieria bullata.
abstract: Nodulation, which is considered the predominant defense reaction to infection in insects, is a complex process influenced by various endogenous factors. However, the precise mechanisms underlying nodulation remain largely unknown. In the present study, we examined the influence of the insect hormones 20-hydroxyecdysone (20E) and juvenile hormone (JH) on the laminarin-induced nodulation reaction in larvae of the flesh fly Neobellieria bullata. Treating third-instar larvae of N. bullata with 20E prior to laminarin injection enhanced the nodulation response in a dose-dependent manner. The ecdysone agonists RH2485, RH5849 and RH0345 similarly enhanced the nodulation reaction, although they were less active than 20E. In contrast to ecdysone stimulation, supplying larvae with JH or the juvenile hormone analogs (JHA), fenoxycarb and pyriproxyfen, significantly impaired their ability to form nodules in response to laminarin. These findings demonstrate for the first time that 20E and JH play an important regulatory role in the nodulation process.
authors.affiliation: Laboratory of Developmental Physiology, Genomics and Proteomics, Department of Animal Physiology and Neurobiology, Zoological Institute, K.U. Leuven, Naamsestraat 59, B-3000 Leuven, Belgium.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Franssens
authors.forename: Guy
authors.initials: G
authors.lastname: Smagghe
authors.forename: Gert
authors.initials: G
authors.lastname: Simonet
authors.forename: Ilse
authors.initials: I
authors.lastname: Claeys
authors.forename: Bert
authors.initials: B
authors.lastname: Breugelmans
authors.forename: Arnold
authors.initials: A
authors.lastname: De Loof
authors.forename: Jozef
authors.initials: J
authors.lastname: Vanden Broeck
mesh_terms: D000818:Animals; D004175:Diptera / Q000187:drug effects / Q000254:growth & development / Q000276:immunology*; D004305:Dose-Response Relationship, Drug; D004441:Ecdysterone / Q000819:agonists / Q000276:immunology* / Q000494:pharmacology; D005936:Glucans; D007605:Juvenile Hormones / Q000276:immunology* / Q000494:pharmacology; D011134:Polysaccharides / Q000276:immunology*
chemical_list: D005936:Glucans; D007605:Juvenile Hormones; D011134:Polysaccharides; D004441:Ecdysterone; C008247:laminaran