Fig. 1: Cryptosporidium life cycle stages revealed by the H2B–mNeon transgene.

a,b, C. parvum infection was monitored by luciferase activity in mice lacking mature T and B cells (a; faeces were measured every 3 d) and HCT-8 cultures (b). Data are mean ± s.d. from three independent biological replicates. c, HCT-8 cultures were infected with H2B–mNeon transgenic parasites and fixed at 24 h (‘Oocyst’, ‘Trophozoite’, ‘Meront’, ‘Late meront’ and ‘Egressing merozoites’), 36 h (‘Merozoite’) and 48 h (‘Early females’, ‘Late females’, ‘Male gamont’ and ‘Male gametes’) time intervals. Green, nuclei; red, cytoplasm (antibody against tryptophan synthase B (TrpB), cgd5_4560). This experiment was performed three times with similar results. Scale bar, 1 µm. d, Morphometric analyses of the size (n = 25) and number (n = 100) of nuclei and the area for each stage (n = 75) on the basis of the markers shown in c. The nuclear area (left) and total area (middle) of parasites stages are shown as mean ± s.d. of individual values represented as dots. The number of nuclei at particular parasite stages are represented as box plots (right). The box shows median and quartile range and whiskers represent extreme values. e, A time-course experiment in which stages were scored using the parameters defined in d revealed abrupt sexualization of cultures at 48 h into culture. Data are mean ± s.d. from three independent biological replicates.