Properties of infectious T1 deoxyribonucleic acid.

T1 deoxyribonucleic acid (DNA) infection of spheroplasts was characterized by the following. A small number of the DNA molecules initiated infectious centers, and a small number of the spheroplasts were infected by T1 DNA. Once a favorable encounter of T1 DNA with spheroplast occurred, a minimum of 20 to 30 min was required for T1 DNA to enter the spheroplast. The mature T1 particles produced in the infection of spheroplasts by T1 DNA were released in a burst, but the average burst size was quite small compared with a normal burst of the phage-infected bacteria. T1 DNA preparations, capable of causing viral growth in spheroplasts, did not require detectable amounts of protein for infectivity, were homogeneous in band and boundary sedimentation, and had a guanine plus cytosine content of 48% and a minimal molecular weight of 35 x 10(6). Denatured T1 DNA, like denatured lambdaDNA, did not infect spheroplasts. Renatured T1 DNA was not infectious; this was in marked contrast to renatured lambdaDNA.