The intention of this protocol is to isolate high molecular weight DNA. This means you should avoid any pipetting without using a wide-bore or cut off pipette tip, vortexing, mixer shakers or anything else which generate a velocity gradient which may shear the DNA. In addition you should be very careful not to introduce nucleases by making up buffers with nuclease-free water. Avoid unnecessary heating and do not freeze, isolated DNA should be stored in the fridge, a good extraction will be stable for months. Currently tested on E. coli\u00a0and human cell lines, however it is likely to work with many gram-negative bacteria and mammalian cells.