Fig. 7. Two-dimensional gel analysis of selected samples shown in Figure 6. Samples of leaf discs agro-inoculated with DNA A (A) or ΔAC2/3 (B) were compared at 5 d.p.i. Note that z intermediates were present in all samples, whereas x and y intermediates were not detectable. A so far unprecedented arc of cccDNA (arrowheads) was observed in all samples during these experiments. These forms presumably represent extremely open chromatin structures with less negative or even positive supercoiling.