Figure 4A: Paraoxon tolerance by soil isolates at 200 ug paraoxon/mL CSM media. Absorbance readings were taken over an eight day period at 600 nm to determine cell density. E. coli transformed w/ Puc19 was used as a negative control. A strain of P. putida possessing the opd gene was used as a positive control. Error bars represent 95% confidence intervals.