The Effect of Metal Pollutants on Cell Growth and TTHERM0058490ExpressioninT etrahymenathermophila
In this experiment, we sought to answer the following question: Do higher levels of metal exposure affect expression of the TTHERM 00584900 gene in Tetrahymena thermophila? The TTHERM 00584900 gene produces an ATP-binding cassette protein that is responsible for removing metals and metalloids from Tetrahymena thermophila. It is hypothesized that the expression of TTHERM 00584900 will increase with exposure to metals. In order to test this hypothesis, Tetrahymena thermophila were randomly assigned to either a control group, which was cultured in a normal growth medium, or a treatment group, whichin addition to the medium was exposed to water contaminated with metals and metalloids. Previous experiments have suggested that Tetrahymena thermophila growth is negatively affected by high metal concentrations. The experimental group was exposed to water mimicking chronic levels of metal pollution found in bodies of water in close proximity to mines. Low doses of contaminated water were given daily to the experimental group over the course of one week. Immediately following the culturing and exposure, RNA extraction, reverse transcription, and gene-specific PCR (including gel electrophoresis) was conducted on the samples from both the control and treatment groups to measure expression of TTHERM 00584900. Because ATP-binding cassette proteins remove metals and metalloids, it was predicted that the TTHERM 00584900 gene would be up-regulated in organisms exposed to chronic levels of metal pollutants. It was also predicted that cell growth rates would be lower for the treatment group, as measured by cell counting with a hemocytometer over the course of the treatment period.