Quantification of plDNA per parasite. Cells were synchronized twice with sorbitol (0 and 48 h), early ring forms were collected at 50 h, counted, and the DNA was processed in duplicate, separated by electrophoresis, blotted and probed for plDNA. (A) Lanes 1 and 2, duplicate samples from 1.1 × 107 parasitized erythrocytes. Lanes 3-7, 0.63, 1.27, 2.54, 5.08 or 10.2 ng pJAZZ-OC LSU construct. N, nicked circular plDNA; IV, form Four; L, linearized circles; CC, covalently closed circular plDNA, Construct, pJAZZ-OC LSU. Arrow indicates well. (B) Standard curve of pJAZZ-OC LSU generated from signal intensities in Panel A and known mass amounts determined by UV absorption; R2 = 0.96.