Meeting Abstract

P2-16   -   Exposing the effects of methyl farnesoate and juvenile hormone mimics on Y-organ ecdysteroid synthesis and gene expression Bentley, VL*; Mykles, DL; Colorado State University; Colorado State University Vanessa.Bentley@colostate.edu

Methyl farnesoate (MF) is the functional juvenile hormone (JH) member that regulates development, reproduction, and molting in crustaceans. Molting is stimulated by the increase of 20-hydroxyecdysone (20-E) titers, the active form of steroid molting hormone, synthesized by the Y-organs (YO). The components of the MF signaling pathway were identified in the YO transcriptome, including the MF/JH receptor Methoprene tolerant (Met), the zinc finger transcription factor Krüppel homolog 1 (Kr-h1), and the MF synthetic pathway enzyme Farnesoic acid O-methyltransferase (FAMeT). These data suggest that MF acts directly on the YO to regulate ecdysteroidogenesis. It is hypothesized that at low hemolymph ecdysteroid titers, such as in intermolt (IM) animals, MF stimulates ecdysteroid synthesis. At high ecdysteroid titers, such as in late premolt (LP) animals, MF inhibits YO ecdysteroid synthesis; thus, leading to the repression of the YO during postmolt (PM). An in vitro culture system was used to determine the effects of MF and JH mimics (Methoprene, Pyriproxifen, Fenoxycarb, and S-Hydroprene) on YO ecdysteroid secretion. YOs from intermolt adult green crabs (Carcinus maenas) were incubated in either a control or MF/JH-mimic culture media for 48 hours with the media replaced every eight hours. Ecdysteroid levels in the culture media samples will be quantified with a competitive ELISA. The expression of MF biosynthetic and signaling genes (e.g., FAMeT, Met and Kr-h1) along with ecdysteroid synthetic and signaling genes (e.g. Halloween genes) will be quantified by qPCR. Supported by NSF (IOS-1922701 and IOS-1456942).