Cyanide Insensitive Culture Form of Trypanosoma brucei

Abstract

ON the basis of ultrastructural and cytochemical observations, Vickerman has suggested^1–3 that the single mitochondrion of sleeping sickness trypanosomes undergoes a cyclical activation and repression during the life cycle of the parasite. Detailed studies of the respiratory metabolism of this group of trypanosomes have been confined to bloodstream stages and forms from established in vitro cultures^4–7. The culture forms are believed to correspond to the midgut stage of the tsetse fly vector⁸. The bloodstream forms lack cytochromes and a functional Krebs cycle⁷; terminal respiration is cyanide insensitive and is mediated largely by extramitochondrial L-α-glycerophosphate oxidase⁶. Established culture forms have cyanide sensitive terminal respiration and a full functional Krebs cycle⁷.