A rapid boiling method for the preparation of bacterial plasmids

A simple and rapid method for preparing plasmids for restriction enzyme analysis has been developed. Bacteria are boiled for 15–40 s and an insoluble clot of genomic DNA and debris is removed by low-speed centrifugation. Plasmids are recovered from the supernatant by isopropanol precipitation and can be resuspended in buffer and immediately restricted. A 5-ml bacterial culture yields enough plasmids for many restriction enzyme digestions, but a single colony on a petri dish or a 0.5-ml miniculture will suffice for a few experiments. In addition, the procedure can be readily adapted for the preparation of plasmids from liter cultures with quantitative yields.