Early development of Gregarina cuneata observed using a transmission electron microscope.
A. Invading sporozoite; host cell microvilli (mv), sporozoite nucleus (n). B–G. Sporozoite transforming into the trophozoite stage; conoid (arrow), developing epimeritic bud (asterisks), host cell (hc), host cell microvilli (mv), micronemes (arrowheads), microtubule (white arrow), nucleus (n), rhoptry-like organelle (r), subpellicular microtubules (double arrowheads). H. Early trophozoite stage. Note the anterior part of the gregarine, covered by a developing cortical vesicle (asterisks), causing an invagination of the host cell (hc) plasma membrane; host cell microvilli (mv), membrane fusion site (in circle), mitochondria (arrowheads), nucleus (n), pellicle (double arrow). Insets show details of the membrane fusion sites. I. Early trophozoite. Note the folded plasma membrane covering the cortical vesicle (asterisks) and forming numerous digitations; host cell (hc), host cell microvilli (mv), membrane fusion site (in circle), nucleus (n). J. Developing trophozoite; cortical vesicle (asterisks), endoplasmic reticulum (er), host cell (hc), host cell microvilli (mv), membrane fusion site (in circle), nucleus (n), pellicle with raising epicytic folds (double arrow). K. The apical end of another maturing trophozoite; amylopectin granules (am), cortical vesicle (asterisks), endoplasmic reticulum (er), host cell (hc), membrane fusion site (in circle), nucleus (n), unknown structure (st).
More »