(a) Schematic representation of C. parvum life cycle.
(b) Scheme and bright-field images of microinjection.
(c) C. parvum 18S rRNA was measured at each time point after injection in differentiated and expanding SI organoids by qRT-PCR (n=2 biologically independent experiments). Mean value at each time point was used for connecting line.
(d) Immunofluorescence of C. parvum epicellular stages in expanding organoids. (top) At 24 hr post-injection, meront I (arrow) and possibly meront II (arrowhead) were observed. (bottom) At 72 hr, a microgamont with 16 nuclei was detected. Sporo-Glo marks epicellular stages. DAPI mark nuclei. Scale bars indicate 2μm. More than 40 meronts I, 10 meronts II and 3 microgamonts were observed independently.
(e) TEM of distinct stages of C. parvum life cycle after injection. Invading sporozoite and meront II were observed in differentiated organoids at 1 day. Trophozoite was observed in expanding organoid at 1 day. PV: parasitophorous vacuole, FO: feeder organelle, AP: amylopectin granule, WB: wall-forming body, LB: lipid body, DG: dense granule, N: nucleus, RB: residual bod, DB: dense band, EDC: electron dense collar, AI: anterior invagination. Scale bars indicate 2μm. Macrogamont, zygote and developing oocyst were detected in expanding organoids at 5 day. More than 2 sporozoites, 4 trophozoites, 5 meronts II, 5 macrogamonts, 1 zygote and 3 oocysts were observed independently.