Invasion of a T. gondii tachyzoite into a human foreskin fibroblast. Note the constriction in the parasite’s plasma membrane that moves from anterior to posterior as the parasite penetrates past the host plasma membrane and into the developing parasitophorous vacuole. Note also the rapid migration of the internalized parasite to a perinuclear region, beginning with an abrupt “yank” on the parasite at ~1:23. Filmed at 35oC on a Zeiss Axiovert microscope (Nomarski optics). The parasites are ~7um long.