In vitro cultivation of cells and a microsporidian parasite of Biomphalaria glabrata (Pulmonata: Basommatophora).

Cells from juvenile heart and gonads of B. glabrata have been grown in vitro for more than 1 year. These cell cultures are not actively mitotic but show other characteristics normal for metazoan cells in culture. They are tolerant of widely variable culture conditions. Challenges with mitogens, mutagens, and altered cyclic nucleotide levels have failed to induce mitosis. A microsporidian parasite grows intracellularly in vitro. The ultrastructural details of sporogeny and pansporoblastic maturation are described. Several pansporoblasts can occur in one snail cell; maturation of spores within a pansporoblast is not synchronous, which is a highly unusual feature. Time-lapse cinemicrography reveals engulfment of free spores by snail cells. Polar tube and sporoplasm release are reported photographically. Drug therapy failed to eliminate the protozoan. The potential value of microsporidia in schistosome control programs is evaluated as slight.