Preparation of large numbers of plasmid DNA samples in microtiter plates by the alkaline lysis method

A protocol is described for the growth and preparation of plasmid DNAs from small culture volumes (250 μl) and utilizing standard 96-well plates. Several hundred plasmids can be prepared simultaneously, yielding sufficient DNA for subsequent analysis by restriction digestion and gel electrophoresis. This protocol may be useful for rapid screening of clones arising in recombinant DNA work such as site-directed mutagenesis, oligonucleotide cassette cloning, deletion analysis, etc. The technique was initially developed to meet our requirement to provide large numbers of cosmid DNAs for restriction enzyme fingerprint analyses in genome mapping projects.