Determining the effect of copper sulfate concentration on the swimming speed of Tetrahymena thermophila

Abstract

To test the toxicity of copper sulphate on the speed of the motile protozoan Tetrahymena thermophila, various concentrations of copper sulfate solution were added to the organism’s growth medium. Cell speed was determined by capturing the organism’s movement using a DinoXcope camera, before analyzing the videos with CellTrack and ImageJ software. Copper sulfate concentrations of 1 ppm, 3 ppm, and 5 ppm were used, as well as both medium and distilled water controls. Tracking the speed of generally slow-moving cells showed a trend of Tetrahymena thermophila having the lowest speed (0.25 +/- 0.03 mm/sec) at the highest copper concentration (5 ppm). However, when measuring speeds of generally fast-moving cells, there was a trend towards Tetrahymena thermophila showing the highest speed (0.35 +/- 0.04 mm/sec) at the highest copper concentration (5 ppm). This particular trend may be due to the fact that toxins are often localized, and when a specific cell is exposed to a high amount of toxin, it tries to escape by swimming faster. Though our results are not statistically significant, we see a trend towards high levels of copper sulfate affecting the organism, with fast-moving cells becoming faster, and slow-moving cells becoming slower.