Ultrastructure of changes at the surface during the early development phases of Taenia ovis cysticerci in vitro

Abstract

Harris A., Heath D. D., Lawrence S. B. and Shaw R. J. 1987. Ultrastructure of changes at the surface during the early development phases of Taenia ovis cysticerci in vitro. International Journal for Parasitology 17: 903–910. Transmission and scanning electron microscopy and conventional, interference, and u.v. light microscopy were used to examine the epithelial membrane and underlying cytoplasm during the early development of Taenia ovis cysticerci in vitro. For 2 h after activation of the oncosphere, blebs of plasma membrane containing cytoplasm and secretory granules were released. Two h later the surface area of the plasma membrane had increased by the elaboration of microvilli. Microvilli increased in length and number for 48 h. Synthesis of granules was observed in two of the four lobes of the penetration glands for at least 4 h in vitro. Granules were present in the surface epithelium 4 h after activation. At 24 h granules remaining in the epithelium were electron lucid. In the presence of heat inactivated serum from sheep immunised against T. ovis oncospheres, an electron dense material was precipitated on and between microvilli within 24–48 h of culture. Material in this position reacted positively with fluorescein-labelled antisheep IgG. When metacestodes became motile after 4–5 days, microvilli were sloughed and replaced by a form of microtriche.