Acidic vesicles of Schistosoma mansoni

The fluorescent probe LysoTracker Red was used to examine for the presence of acidic vesicles in cercariae and schistosomula of Schistosoma mansoni. A cidic vesicles were widely distributed throughout the body of freshly trans formed schistosomula and 24-h-old schistosomula but were absent from cercar iae. The vesicles of freshly transformed schistosomula were undetectable af ter incubation with drugs that affect the functionality of acidic vesicles including monensin, ouabain, primaquine, and amiloride. In 24-h transformed schistosomula, the same effect was observed with monensin but not with oua bain, primaquine or amiloride. Praziquantel also affected the acidic vesicl es of the schistosomula. We suggest that these acidic vesicles could be lar ge lysosome-like organelles.