Conditions affecting the isolation from transformed cells of Bacillus subtilis of high-molecular-weight single-stranded deoxyribonucleic acid of donor origin.

The deoxyribonucleic acid (DNA) extraction procedure of Piechowska and Fox was evaluated to determine which steps are required for the isolation of high-molecular-weight single-stranded material from transformed cultures of Bacillus subtilis. The results indicate that high-molecular-weight single-stranded DNA can be isolated when certain basic proteins are present at the time of lysis. In the absence of such protective agents as lysozyme or cytC the single-stranded DNA is degraded. The single-stranded DNA can also be protected by being treated with lysozyme at low temperature. The high molecular weight of this single-stranded material and its kinetics of appearance are consistent with its being an intermediate in the transformation process.