PARENT SESSION

PT07 Chemical and Biological Analysis of Endocrine Disrupting Compounds
Exhibit Hall
8:00 AM - Tuesday

(PT125) Tissue specific localization of APGWamide in TBT exposed Mud Snail, Ilyanassa obsoleta.

Romano, J.¹, McClellan-Green, P.^{1, 2}, ¹ Duke University Marine Laboratory, Beaufort, NC, USA² North Carolina State University, Raleigh, NC, USA

ABSTRACT- Imposex, the masculinization of female snails, has been documented world wide and has been casually link to organotin exposure. This condition is characterized by the abnormal development of male Accessory Sex Organs (ASO) in female gastropods. ASO development in males is induced by a neuropeptide hormone termed Penis Morphogenic Factor (PMF). PMF has not been identified but is hypothesized to be the neuropeptide APGWamide. APGWamide has been found to induce imposex in Ilyanassa obsoleta and play an important role in male copulatory behavior. In this study we investigated the localization of APGWamide expression in the marine gastropod I. obsoleta by using immunohistochemistry. Snails were exposed to 10, 20, and 50 ng/L TBT for 45 days and prepared for immunohistochemical staining using an anti-APGWamide polyclonal antibody. Sections of head and abdomen in males, females, and imposex females were cut at 7m intervals. Results showed APGWamide immuno-reactivity in abdomens of control and TBT exposed males and imposex females only. It was also noted that the presence of this peptide increased with increasing exposure to TBT. To determine whether APGWamide expression corresponded to neuronal regions, Vogt's Cresyl Violet (VCV) stain was applied to companion sections in order to identify nissl bodies. Nissl bodies are subcellular structures found only in nerve tissue and cells. APGWamide immuno-reactivity and the identification of nissl bodies occurred in same locations within the abdomen but only nissl bodies were found in the head region. This indicates that 1) TBT exposure and/or imposex induction stimulates APGWamide expression; and 2) that the abdominal ganglia are responsible for the production of this peptide in the mud snail, Ilyanassa obsoleta.

Key words: APGWamide, imposex, Ilyanassa obsoleta