An Aqueous Solution Containing Soluble Substances From PVC Char Has No Effect on the Rate of Transformation in E. coli Cells
(1) Lowell High School, Lowell, Massachusetts, (2) Middlesex Community College, Bedford, Massachusetts
In transformation, bacterial cells can take in exogenous DNA molecules, or plasmids, some of which may contain genes for antibiotic resistance, or other factors which may aid in bacterial survival. These exogenous DNA sequences contribute to the evolution of antibiotic-resistant bacteria. Polyvinyl chloride (PVC) is a widely used plastic that poses many health hazards. Substantial research has been conducted on the harmfulness of PVC gas released when burned, yet relatively few studies have focused on the solid product, or char, of incinerating PVC. This study aimed to determine whether or not PVC char has an effect on bacterial transformation. It was hypothesized that PVC char would not increase transformation rates. In this experiment, Escherichia coli cells were attempted to be made competent to take up a pFluoroBlueTM plasmid, which contains IPTG, a fluorescent molecule. E. coli cells were treated with CaCl2, PVC char solution, or a 50-50 mixture of CaCl2/PVC char solution. The CaCl2-treated cells produced between 1 and 10 fluorescing colonies, the 50-50 mixture produced one or no fluorescing colonies, and the PVC char solution produced no fluorescing colonies. PVC char alone did not cause the transformation of E. coli cells, yet it was observed that E. coli did grow on the agar plates containing Ampicillin. This finding is significant and warrants further investigation to determine whether or not PVC char decreases the effectiveness of the antibiotic Ampicillin, or whether PVC char induces mutations for antibiotic resistance without the acquisition of plasmids or foreign DNA from the environment.