Cells were lysed in DNA Lysis solution (100 mM Tris, pH 8.5, 5 mM EDTA, 200 mM NaCl, 0.2% (w/v) sarcosyl, and 100 µg/ml fresh proteinase K) overnight at 50°C. DNA was precipitated by the addition of an equal volume of NaCl-ethanol mixture (150 µl of 5 M NaCl in 10 ml cold 95% ethanol) and then washed three times in 70% ethanol prior to resuspension in water with RNAseA overnight at 4°C.
