Isolation procedure for all plasmid sizes from all bacteria (Crosa et al., 1994)
- Centrifuge 2 ml of a culture and wash pellet in 2 ml of the following TE buffer: 0.05 M Tris,
pH 8.0, 0.01 M EDTA. Resuspend in 40 µl of the same TE buffer
- Fill 0.6 ml of freshly prepared lysis buffer (TE buffer used above with 4%SDS, pH adjusted to
12.45) into Eppendorf tube and add the cell suspension to the lysis buffer, mix gently
- Complete lysis by incubating at 37°C for 20-30 min
- Add 30 µl of 2 M Tris, pH 7.0 for neutralization, mix gently
- Add 024 ml of 5 M NaCl for precipitation of chromosomal DNA and protein and incubate on
ice for 4 hrs
- Centrifuge for 10 min and transfer supernatant into new tube for ethanol precipitation (as
usual) or for previous extraction with phenol/chloroform (see Method 2)