Mitochondrion of the Trypanosoma brucei long slender bloodstream form is capable of ATP production by substrate-level phosphorylation.
Level 5 - mechanism / opinion, no new human data
In vitro parasite genetic and biochemical bench study (no human data)
PubMed 37819951 · doi:10.1371/journal.ppat.1011699
What was done
Investigated how the long slender bloodstream form of *Trypanosoma brucei* generates mitochondrial ATP to maintain mitochondrial membrane potential (ΔΨm). Researchers generated knockout cell lines for the mitochondrial ATP/ADP carrier (AAC) and succinyl-CoA synthetase (SCS), and used RNA interference (RNAi) to rapidly suppress SCS expression. They evaluated parasite growth, virulence, ΔΨm, mitochondrial ATP content, and sensitivity to the AAC inhibitor carboxyatractyloside under standard and nutrient-limited culture conditions.
What was found
Deletion of AAC had no effect on parasite growth, virulence, or ΔΨm levels. SCS knockout altered parasite metabolism, lowered virulence, reduced mitochondrial ATP content, and caused a 25-fold increase in sensitivity to carboxyatractyloside. Rapid SCS depletion via RNAi under nutrient-limited conditions strongly impaired parasite growth and ΔΨm. Absolute baseline values and specific ATP concentrations were not quantified in the abstract.
Why it matters
This study overturns the paradigm that bloodstream-form trypanosomes depend entirely on imported cytosolic ATP, showing that mitochondrial substrate-level phosphorylation is active and functionally important during metabolic stress.
Limits
The findings derive entirely from in vitro parasite models with no human subjects or direct clinical data. Exact quantitative baseline metrics for ΔΨm, growth rates, and ATP levels were not provided in the abstract.
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