Effects of Daunomycin and Daunomycin-protein conjugates on the ultrastructure of Trypanosoma rhodesiense.

The nucleus (but not the kinetoplast) of Trypanosoma rhodesiense is the principal target for trypanocidal attack by Daunomycin in vitro and Daunomycin-protein conjugates in vivo; free Daunomycin is inactive in vivo. Nucleolar segregation and abnormal distribution of heterochromatin occur after drug treatment as in tumour cells. Other abnormal changes include formation of cytoplasmic clefts and autophagic vacuoles, increased prominence of the tubular collection system, and exocytotic vesicle production. Large masses of ferritin accumulate in white cells after treatment with the drug-ferritin conjugate but no ferritin was detectable in trypanosomes.