Meeting Abstract
P1.11 Thursday, Jan. 3 Physiological Responses of Utterbackia imbecillis (Bivalvia: Unionidae) to Acute Exposure to Sub-Lethal Dosage of Copper PILARCZYK, M.M.**; JOHNSON, E.C.; DIMOCK, R.V., JR.; Wake Forest University; Wake Forest University; Wake Forest University pilamm5@wfu.edu
The distribution, abundance, sedentary lifestyle, and suspension feeding of the freshwater mussel, Utterbackia imbecillis, make this bivalve an ideal indicator species for use in environmental biomonitoring. Since the molecules that underlie the stress response are highly conserved across a broad array of phyla, we explored the possibility of their use as biomarkers. This study evaluated cellular and organismal physiological responses of U. imbecillis to acute copper stress. Copper is a common pollutant in aquatic ecosystems and is toxic to many molluscs. Adult U. imbecillis were exposed to 100 ppb CuCl2, a sublethal concentration as determined by preliminary experiments. We examined relative transcript abundance of the stress-sensitive molecular chaperone, HSP70, under normal and copper stress conditions. Degenerate HSP70 and actin primers were designed using conserved sequences, with a priority given to molluscan species. The degenerate primers were used to amplify HSP70 and actin cDNA fragments which were 95% and 87% identical to sequences for marine bivalves. Based on this sequence information, we developed gene-specific primers for U. imbecillis HSP70 and actin. Total RNA was extracted from adductor muscle tissue from copper-treated and control animals, and HSP70 expression was normalized to that of actin. Electrophoretic images and optical densities of the amplified bands were analyzed using imaging software, and we will report the relative variation between each treatment and the control sample. The organismal physiological parameters of valve adduction, heart rate, and oxygen consumption, measured with standard techniques, were assessed for individual animals both before and after copper exposure. All of these experiments are continuing, and the results will be forthcoming.
