Bioassays of Compounds with Potential Juvenoid Activity on \u3ci\u3eDrosophila melanogaster\u3c/i\u3e: Juvenile Hormone III, Bisepoxide Juvenile Hormone III, and Methyl Farnesoates

Metabolites of the 6,7,10,11 bisepoxide juvenile hormone III (JHB3), and other potential juvenoids, were tested for juvenile hormone activity using early instar or early stage pupae of Drosophila mela-nogaster. Importantly, methyl farnesoates were tested as they might have JH-like activity on Dipteran juveniles. Larvae were exposed to compounds in medium, or the compounds were applied to white puparia. In the assays employed in the present study, there was no indication for JH activity associ-ated with the metabolites of JHB3. The activity of methyl farnesoate (MF) was higher than that of JH III and far greater than bisepoxide JH III. As opposed to the two endogenous juvenile hormones, methyl farnesoate has weak activity in the white puparial bioassay. When fluorinated forms of me-thyl farnesoate, which is unlikely to be converted to JH, were applied to Drosophila medium to which fly eggs were introduced, there was a high degree of larval mortality, but no evidence of subsequent mortality at the pupal stage. One possible explanation for the results is that methyl farnesoate is active as a hormone in larval stages, but has little activity at the pupal stage where only juvenile hormone has a major effect

Bioassays of Compounds with Potential Juvenoid Activity on \u3ci\u3eDrosophila melanogaster\u3c/i\u3e: Juvenile Hormone III, Bisepoxide Juvenile Hormone III, and Methyl Farnesoates

Metabolites of the 6,7,10,11 bisepoxide juvenile hormone III (JHB3), and other potential juvenoids, were tested for juvenile hormone activity using early instar or early stage pupae of Drosophila mela-nogaster. Importantly, methyl farnesoates were tested as they might have JH-like activity on Dipteran juveniles. Larvae were exposed to compounds in medium, or the compounds were applied to white puparia. In the assays employed in the present study, there was no indication for JH activity associ-ated with the metabolites of JHB3. The activity of methyl farnesoate (MF) was higher than that of JH III and far greater than bisepoxide JH III. As opposed to the two endogenous juvenile hormones, methyl farnesoate has weak activity in the white puparial bioassay. When fluorinated forms of me-thyl farnesoate, which is unlikely to be converted to JH, were applied to Drosophila medium to which fly eggs were introduced, there was a high degree of larval mortality, but no evidence of subsequent mortality at the pupal stage. One possible explanation for the results is that methyl farnesoate is active as a hormone in larval stages, but has little activity at the pupal stage where only juvenile hormone has a major effect

Establishment of a New Cell Line from Lepidopteran Epidermis and Hormonal Regulation on the Genes

When an insect molts, old cuticle on the outside of the integument is shed by apolysis and a new cuticle is formed under the old one. This process is completed by the epidermal cells which are controlled by 20-hydroxyecdysone (20E) and juvenile hormone. To understand the molecular mechanisms of integument remolding and hormonal regulation on the gene expression, an epidermal cell line from the 5th instar larval integument of Helicoverpa armigera was established and named HaEpi. The cell line has been cultured continuously for 82 passages beginning on June 30, 2005 until now. Cell doubling time was 64 h. The chromosomes were granular and the chromosome mode was from 70 to 76. Collagenase I was used to detach the cells from the flask bottom. Non-self pathogen AcMNPV induced the cells to apoptosis. The cell line was proved to be an epidermal cell line based on its unique gene expression pattern. It responded to 20E and the non-steroidal ecdysone agonist RH-2485. Its gene expression could be knocked down using RNA interference. Various genes in the cell line were investigated based on their response to 20E. This new cell line represents a platform for investigating the 20E signaling transduction pathway, the immune response mechanism in lepidopteran epidermis and interactions of the genes

JUVENILE HORMONE IN RELATION TO THE LARVAL-PUPAL TRANSFORMATION OF THE CECROPIA SILKWORM

Volume: 142Start Page: 310End Page: 32

JUVENILE HORMONE-INDUCED DELAY OF METAMORPHOSIS OF THE VISCERA OF THE CECROPIA

Volume: 148Start Page: 429End Page: 43

Orchestration of insect moulting and metamorphosis: hormonal regulation and molecular switches

<div>Lecture given by Professor Lynn M. Riddiford, Department of Biology, University of Washington, Seattle, USA at the Waite Campus, University of Adelaide, 9.12.1996.</div><div><br></div><p>This lecture is part of the Campus Seminars and Distinguished Lecturer Series, Waite Campus, University of Adelaide, 1991 – 1997. </p> <a href="https://figshare.com/projects/Campus_Seminars_and_Distinguished_Lecturer_Series_Waite_Campus_University_of_Adelaide/17756">https://figshare.com/projects/Campus_Seminars_and_Distinguished_Lecturer_Series_Waite_Campus_University_of_Adelaide/17756</a

Regulation of Transcription Factors MHR4 and βFTZ-F1 by 20-Hydroxyecdysone during a Larval Molt in the Tobacco Hornworm, Manduca sexta

AbstractDuring the last larval molt in Manduca sexta, a number of transcription factors are sequentially expressed. Unlike E75A and MHR3, whose mRNAs are induced when the ecdysteroid titer increases, the expression of MHR4 mRNA occurs transiently at the onset of the decline of ecdysteroid titer followed by βFTZ-F1 mRNA expression when the ecdysteroid titer becomes low. When day 2 fourth epidermis was exposed to 20-hydroxyecdysone (20E) in vitro, MHR4 mRNA appeared between 12 and 21 h, peaked at 24 h, and then declined. Using the protein synthesis inhibitors cycloheximide and anisomycin both in vivo and in vitro, we found that the MHR4 transcript was directly induced by 20E and required the presence of 20E for its expression. The accumulation of MHR4 mRNA, however, did not occur until a 20E-induced inhibitory protein(s) disappeared. This control of MHR4 expression is unique among the ecdysone-induced transcription factors. When the epidermis was cultured with 20E, βFTZ-F1 mRNA was not induced until after the removal of 20E as previously found for Drosophila and the silkworm Bombyx mori. The presence of juvenile hormone had no effect on accumulation of either transcript

THE CONTROL OF EGG MATURATION BY JUVENILE HORMONE IN THE TOBACCO HORNWORM MOTH, MANDUCA SEXTA

Volume: 146Start Page: 377End Page: 39

ROLE OF THE CORPORA CARDIACA IN THE BEHAVIOR OF SATURNIID MOTHS. I. RELEASE OF SEX PHEROMONE

Volume: 140Start Page: 1End Page: