Figure 3. mfabI plasmid propagation in liquid culture.

(A) Growth curves. Equalized overnight broth culture of untransformed DH10B, pF, or pF2-transformed clones (two for each; N = 2) were seeded in LB broth with different concentrations of triclosan (0, 1, or 16 µM; indicated by numbers in parentheses), and grown at 37 (left) or 32°C (right panel), with constant 250-rpm shaking. Samples were taken at different time points for OD measurement. (B) Plasmid DNA yields of pF and pF2 with different growth conditions. DNA was extracted from the cultures in the growth curve experiment shown in (A) at the end point (17 hr.). (C) Plasmid retention (triclosan resistance) after different culture conditions. Equalized amounts of cells from the end point cultures in the growth curve experiments were plated with or without 1 µM triclosan. Triclosan resistance was calculated by dividing the number of colonies formed on the triclosan plate by that on the antibiotic-free plate for individual cultures. pF and pF2 clones tend to form more colonies when plated with triclosan, resulting in a counterintuitive >100% triclosan resistance; 16 µM triclosan-cultured cells might have developed higher triclosan dependency, and thus were less enhanced by 1 µM triclosan on colony formation. Error bars show standard deviations.