CONTROL OF CILIARY ACTIVITIES OF SCHISTOSOMA-MANSONI MIRACIDIA USING TRITON-EXTRACTED PARASITES

Extraction with 0.04% (w/v) Triton X-100 for 3 min removed the cell me mbrane from the locomotory cilia of Schistosoma mansoni miracidia whil e leaving the motile apparatus apparently intact. Immediately after Tr iton-extracted miracidia were treated by the reactivating solution con taining ATP and magnesium ions (Mg2+) at pH 8.1, nearly 100% of Triton -extracted miracidia showed the ciliary beating and swam forward in a manner resembling that of a normal miracidium. In the standard reactiv ating solution (2 mM ATP, 2 mM Mg2+, pH 8.1), Triton-extracted miracid ia swam at a speed of 580 mu m/sec; the comparable value for live mira cidia in dechlorinated tap water was 2,200 mu m/sec. The swimming velo city of Triton-extracted miracidia was dependent on ATP and Mg2+ conce ntration, pH, and salinity. In a solution containing 0.9% NaCl, Triton -extracted miracidia were not reactivated. Among the nucleotides teste d, only ATP was found to induce a significant amount of ciliary motili ty. In terms of divalent cation specificity, only Mg2+ was capable of producing normal motility. Barium and calcium ions (at 0.5 mM CaCl2) a lso were capable of activating ciliary motility but were less effectiv e stimulants than Mg2+. However, in 1 mM CaCl2, no ciliary reactivatio n was observed and cilia became detached from the body surface of the miracidia. Vanadium inhibited ATP-reactivated ciliary beating of Trito n-extracted miracidia.