Effect of Copper Sulfate on the Change in Speed of Caenorhabditis elegans

Abstract

Changes in the behaviour of the free--‐living nematode Caenorhabditis elegans are believed to be an effective indicator of toxic exposures. Copper is a known neurotoxin of C. elegans when consumed in excess amounts (Gaggelli et al. 2006). This experiment aimed to evaluate the change in the rate of movement of C. elegans after exposure to different concentrations of copper sulfate. The nematodes were expected to show a greater decrease in speed after being in contact with a more concentrated CuSO4 solution. A drop of the solution was delivered to a single nematode on an agar plate. The nematode was submerged in the solution for a short period of time and its speed was measured before and after exposure. Introducing the nematodes to distilled water showed an average decrease in speed of 73 μm/s after treatment. When exposed to a 0.06 mM CuSO4 solution, the average decrease in speed was found to be 93 μm/s, and after treatment with a 0.46 mM CuSO4 solution, the average decrease in speed was found to be 64 μm/s. At each concentration of treatment solution, the speed of the nematodes decreased following exposure to the CuSO4 solution. However, there was no significant difference in the decrease in speed for the three different treatments. Although excess amounts of copper are known to cause nerve damage in C. elegans (Hedges 2010), the exposure time in this experiment may not have been long enough to cause such an effect.