Effect of putrescine on the respiration of Trypanosoma brucei brucei

Abstract

Listen

Translate article

When bloodstream forms of Trypanosoma brucei brucei were exposed to exogenous putrescine for 24 h during in vitro culture, the rate of O 2 consumption increased significantly in a concentration-related and time-dependent manner. Trypanosomes cultured with 100 μM dl-α-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, were depleted of intracellular putrescine, and the rate of O 2 consumption decreased by more than 50%. This effect could be abrogated if 100 μM putrescine was also present. A similar pattern was observed in trypanosomes harvested from rats after 36 h of DFMO treatment. If such trypanosomes were placed in culture for 2 h with 100 μM putrescine, the rate of O 2 consumption returned to that of controls. When an intraperitoneal injection of putrescine was given to infected rats 18 h after commencement of DFMO treatment, rates of O 2 consumption in the trypanosomes were found to return to control values. The addition of putrescine, spermidine or Mg 2+ did not affect rate of O 2 consumption in enriched mitochondrial preparations. However, when putrescine was present throughout the preparation of mitochondrial fractions, there was an increase of 23% in O 2 uptake, which was 23% higher than in the controls. Putrescine may modulate trypanosomal respiration by stabilizing mitochondrial membranes.