Figure 2

Estimation of the relative size of colony forming units. A) Semi-Log plot of optical density at 600 nm as a function of bacterial (× = Bt; + = Ss) concentration (δ = CFU mL⁻¹). We have used the semi-Log format in this figure only in order to show all data on the same scale. All results are linear (for OD ≤ 0.5, ${\rho }_{x\cdot y}^2$ = 0.999 [t _ρ = 54.7, P = 1.35 × 10⁻⁵] and 0.997 [t _P = 25.8, P = 1.28 × 10⁻⁴] for Bt and Ss, respectively) on a non-Log scale. B) The ratio of Bt δ-normalized OD (~0.5 or less) at 600 nm to this same variable associated with Ss plotted with δ.