Intracellular forms of lambda deoxyribonucleic acid in Escherichia coli infected with clear or virulent mutants of bacteriophage lambda.

Weissbach, Arthur (National Institutes of Health, Bethesda, Md.), Allan Lipton, and Arnold Lisio. Intracellular forms of lambda deoxyribonucleic acid in Escherichia coli infected with clear or virulent mutants of bacteriophage lambda. J. Bacteriol. 91:1489-1493. 1966.-Infection of either the sensitive or lysogenic strain of Escherichia coli K-112S by lambda(+) leads to the formation of a new phage deoxyribonucleic acid (DNA) species having the properties of a twisted circular DNA duplex. This new phage DNA species is also seen in cells infected with clear or virulent mutants of lambda which cannot lysogenize, or do so at a low frequency. The sedimentation rate of circular lambda DNA duplex at various pH values and its lability were examined.