Meeting Abstract

P1.79  Jan. 4  Gene expression and hemolymph cations in the freshwater crayfish Procambarus clarkii during cold acclimation GILLEN, C.M.*; GAO, Y.; NIEHAUS-SAUTER, M.M.; WYLDE, M.; WHEATLY, M.G.; Kenyon College, Gambier, OH; Wright State University, Dayton, OH; Kenyon College, Gambier, OH; Kenyon College, Gambier, OH; Wright State University, Dayton, OH gillenc@kenyon.edu

We have investigated the effect of cold exposure on the freshwater crayfish, Procambarus clarkii. Crayfish were held at 4 degrees Celsius for 21 days and a control group was held at room temperature. Concentrations of hemolymph cations and the expression of two genes, eukaryotic elongation factor 1B gamma (eEF1B&gamma) and sarcoplasmic calcium binding protein 1 (SCP1), were examined at days 7 and 21 (n = 4-6 crayfish per treatment). Hemolymph was sampled, diluted 1:100, and analyzed by cation chromatography. Hemolymph K and Ca were unchanged 7 and 21 days after cold exposure. In contrast, hemolymph Mg was increased by 89% after 7 days and by 48% after 21 days. We assessed expression of eEF1B&gamma and SCP1 by real-time PCR using the relative quantification method and using 18s ribosomal RNA as an internal calibrator. eEF1B&gamma expression was not significantly changed after 7 days of cold exposure compared to room temperature controls in gill, hepatopancreas, antennal gland, tail muscle and heart muscle. SCP1 expression was decreased by 10-fold in gills and by 7-fold in heart muscle after 7 days of cold exposure compared to room temperature controls and was unchanged in tail muscle and antennal gland. SCP1 expression is also decreased during premolt and postmolt, indicating a similar pattern of SCP1 expression during molting and cold exposure. (Funded by NSF 0445202 to MGW, YG and CMG).