Meeting Abstract

P2.134  Sunday, Jan. 5 15:30  Effect of salinity on gene expression for enzymes in the methyl farnesoate synthesis pathway in the green crab Carcinus maenas. LOVETT, D.L.*; WILLIAMS, M.; PULIDO, S.; GOLDFARB, A.M.; The College of New Jersey, Ewing lovett@tcnj.edu

We have previously reported that hemolymph levels of methyl farnesoate (MF) in the green crab Carcinus maenas increase in response to exposure of crabs to dilute seawater (< 26 ppt salinity) (Lovett et al., 2001, 2006). In a study of isolated mandibular organs (MOs), MF secretion increased when the concentration of ions in the hemolymph (specifically Ca²⁺) decreased (Lovett et al. , 2008). In a study of Homarus americanus, Li et al. (2010) found that eyestalk ablation, which typically stimulates MF secretion by the MOs, was accompanied by an increase in transcript level for farnesoic acid O-methyltransferase (FAOMeT), the terminal enzyme in MF synthesis. The current study examined transcript levels for enzymes in the MF synthetic pathway in MOs of C. maenas. Crabs either were acclimated to high salinity (32 ppt) or low salinity (10 ppt) seawater or were acutely transferred to low salinity after acclimation to high salinity. Exposure to dilute seawater resulted in an increase in transcript levels for FAOMeT in MOs. Thus, change in MF levels in response to salinity change appears to be regulated, at least in part, at the transcriptional level. This study was supported in part by NSF Grant DBI-0933977.