(A) and (B), kDNA isolated from TbPIF2 overexpression cells one day after induction. Black arrow, long dense connection between the two sister networks; empty arrowhead, maxicircle loops with one linear branch. Bar, 500 nm. (C), EM of θ-type replicating maxicircles. After in vivo trioxsalen cross-linking, kDNA was isolated, decatenated by topoisomerase IV and analyzed by EM. Arrows indicate branch points. Bar, 500 nm.