A STUDY OF GRANULES AND OTHER CHANGES IN PHASE-CONTRAST APPEARANCE PRODUCED BY CHEMOTHERAPEUTIC AGENTS IN TRYPANOSOMES.

The morphological changes produced by four series of organic trypanocidal drugs have been studied by quantitative and by qualitative methods using phase-contrast and fluorescence microscopy. Basic drugs were absorbed rapidly into the region of the kinetoplast; acidic drugs did not affect this region. Faint granules, which were present in some trypanosomes before the administration of drugs, absorbed the drugs and increased in contrast relative to the cytoplasm. Hydroxystilbamidine, quinapyramine, related compounds, and possibly also suramin produced additional granules which did not contain drug. These additional granules are similar to the granules (volutin granules) which occur in trypanosome infections (not treated with drugs) when trypanosomes are about to be cleared from the blood. Homidium did not produce additional granules.