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Physiological activation of the mitochondrion and the transformation capacity of DFMO induced intermediate and short
1Department of Biology, University of Dayton, Ohio.
Abstract:
Bloodstream forms of Trypanosoma brucei brucei (EATRO 110) were cultured with 100 microM difluoromethylornithine (DFMO). After 48 hr, intracellular putrescine was depleted and cells were positive when histochemically stained for the mitochondrial marker enzyme, NAD diaphorase, and exhibited mitochondrial proliferation and cristae development when examined by electron microscopy. This suggested that the mitochondrion was undergoing the physiological transformation necessary for successful transmission of the bloodstream form to the vector, namely the initiation of development of a TCA cycle and cytochrome system. The short stumpy forms that appeared by day 4 of culture, although physiologically transformed, were not viable in so far as they were not capable of transforming to procyclic trypomastigotes when introduced into SDM-79 medium. When rats infected with T. b. brucei were given 4% (w/v) DFMO in their drinking water, they were cured within 72 hr. Trypanosomes removed from animals and stained for NAD diaphorase showed mitochondrial transformation, as well as an intermediate and short stumpy morphology, at 36 and 60 hr, respectively. Data from this study on the growth and transformation characteristics of the DFMO induced intermediate and short stumpy form trypanosomes supports the observation that the intermediate form, and not the short stumpy form, is able to successfully transform to procyclic trypomastigotes.
Insights
Difluoromethylornithine (DFMO) treatment induces mitochondrial transformation in Trypanosoma brucei brucei, enabling bloodstream forms to develop. However, only intermediate forms, not short stumpy forms, can transform into procyclic trypomastigotes.
Area of Science:
- Parasitology
- Molecular Biology
- Biochemistry
Background:
- Trypanosoma brucei brucei causes African trypanosomiasis.
- The parasite undergoes morphological and metabolic transformations for transmission between hosts.
- Understanding these transformations is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the effect of difluoromethylornithine (DFMO) on the transformation of Trypanosoma brucei brucei.
- To determine the role of mitochondrial development in parasite transmission.
- To assess the viability of DFMO-induced parasite forms.
Main Methods:
- In vitro culture of Trypanosoma brucei brucei with DFMO.
- Histochemical staining for mitochondrial marker enzyme NAD diaphorase.
- Electron microscopy to examine mitochondrial ultrastructure.
- In vivo treatment of infected rats with DFMO.
- Morphological analysis of trypanosomes at different time points.
Main Results:
- DFMO treatment depleted intracellular putrescine and induced mitochondrial proliferation and cristae development in bloodstream forms.
- DFMO-induced short stumpy forms were not viable for transformation into procyclic trypomastigotes.
- In vivo, DFMO cured infected rats within 72 hours.
- Trypanosomes from treated rats showed mitochondrial transformation and intermediate/short stumpy morphology.
- Intermediate forms, unlike short stumpy forms, successfully transformed into procyclic trypomastigotes.
Conclusions:
- DFMO induces critical physiological transformations in Trypanosoma brucei brucei, including mitochondrial development.
- The intermediate trypanosome form, not the short stumpy form, is the viable precursor for procyclic trypomastigote development.
- DFMO shows potential as a therapeutic agent against African trypanosomiasis by disrupting parasite transmission stages.