1. Briefly vortex cysts directly after incubation in Stage 1 solution.
2. Sediment cysts for 5 min, room temperature, at 8000 g on tabletop centrifuge.
3. Discard supernatant and resuspend cysts
in 1.5 ml of pre-warmed Stage 2 excystation solution in the Eppendorf tube. Vortex
briefl y to resuspend parasites.
4. Incubate tubes at 37°C for 1 h. Vortex gently every 15 min.
5. Briefly vortex samples before sedimenting
cysts in tabletop centrifuge at 8000 g at
room temperature for 5 min.
6. Discard supernatant and resuspend parasites in 1.5 ml of pre-warmed complete
modified TYI-S-33 (made on the day of
excystation).
7. Incubate tubes at 37°C for 1 h with periodic agitation.
8. Concentrate excyzoites in tabletop centrifuge
at 8000g at room temperature for 5 min.
9. Aspirate all but ~100l of medium and resuspend before counting excyzoites.
10. Enumerate excyzoites on a hemocytometer. Excyzoites will have motility and
this will assist one to differentiate the excyzoites from the non-excysted cysts. See
Fig. 23.8E for an image of an excyzoite.