GOMEZ, Andrea M.*; LEE, K.J.; CHANG, E.S.; MYKLES, D.L.; Colorado State University, Fort Collins; Colorado State University, Fort Collins; Bodega Bay Marine Lab, Bodega Bay: Investigating the Role of Nitric Oxide in the Signaling Pathway Regulating Ecdysteroid Secretion in the Crustacean Molting Gland

Crustacean growth and development is regulated by the fundamental process, ecdysis. Ecdysteroids, the hormones responsible for this process, are produced in the Y-Organs (YO) and located in the cephalothorax. Synthesis of ecdysteroid is inhibited by molt-inhibiting hormone (MIH), a neurosecretory peptide produced in the X-Organ/Sinus Gland Complex, located in the eyestalks of the animal. Little is known about the components involved in this MIH signaling pathway, though recent research has confirmed the presence of Guanylyl Cyclase and Nitric Oxide Synthase in YO tissue. The roles of these two putative secondary messengers in this pathway will be evaluated using an in vitro assay technique. Tropical Land Crabs, Gecarcinus lateralis, were subjected to Eyestalk Ablation (ESA), 2 days prior to removal of the YOs. Removal of the eyestalks removes the source of MIH and subsequently stimulates ecdysteroid secretion by the YOs. Guanylyl Cyclase and Nitric Oxide Synthase stimulators/inhibitors were introduced to the YO culture and incubated for 4.5 hours. Determination on the effects these components had on ecdysteroid secretion has elucidated their roles in the MIH signaling pathway. Supported by NSF (IBN-0342982) and scholarship to AMG by the Arnold and Mabel Beckman Foundation.