prepared from cell pellets (OD600nm= 10) using the hydrophobicinteraction HPLC method described before by Diogo et al. (2000). A15 PHE PE HIC column (4.6 mm × 10 cm) from GE Healthcare wasfirstly equilibrated with 1.5 M ammonium sulfate in 10 mM Tris,pH 8.0 (1 mL/min). Thirty L of lysate samples were injected andisocratic elution was performed with the equilibration buffer for1.4 min and then with 10 mM Tris, pH 8.0 buffer for 0.9 min. At2.3 min, the column was re-equilibrated with 1.5 M ammoniumsulfate. Plasmid concentration was determined from a calibrationcurve (5–100 g/mL).