Elaboration of mitochondrial function during Trypanosoma brucei differentiation

Ej, Bienen; Hill, G. C.; Ko, Shin

doi:10.1016/0166-6851(83)90118-4

Cited by 47 publications

(28 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Procyclic forms of 667 which had been in culture for several months were used for some comparative experiments. These cells were initially transformed from bloodstream forms in a semi-defined medium as previously described (Bienen et al, 1983), with the addition of 5 mM cis-aconitate to accelerate differentiation (Brun and Schonenberger, 1981).…”

Section: Methodsmentioning

confidence: 99%

Non‐cytochrome mediated mitochondrial ATP production in bloodstream form Trypanosoma brucei brucei

Ej¹,

Rk²,

Pollakis³

et al. 1993

European Journal of Biochemistry

View full text Add to dashboard Cite

The life cycle of Trypanosoma brucei brucei involves a series of differentiation steps characterized by marked changes in mitochondrial development and function. The bloodstream forms of this parasite completely lack cytochromes and have not been considered to have any Krebs cycle function. It has been suggested that glycolysis is the sole source of ATP in all bloodstream forms. However, earlier results indicated that in the mitochondria of the transitional intermediate/short stumpy bloodstream forms, the biochemical pathways are present that could allow intra-mitochondrial production of ATP. Using a high mannitol buffer to enhance permeability, we confirm previous observations showing that transitional forms maintain motility and respiratory activity with 2-oxoglutarate as the sole substrate. Using a luminometer to measure intracellular ATP levels via the luciferinlluciferase chemiluminescence assay, we show that these same transitional forms, but not long slender forms, maintain high levels of intracellular ATP in the presence of 2-oxoglutarate. Further, in the presence of bongkrekic acid, an inhibitor of the mitochondrial adenine nucleotide translocase, ATP levels are reduced with subsequent death and lysis of the cells when 2-oxoglutarate, but not glucose, is used as sole substrate. These data are direct evidence of ATP production by transitional bloodstream form mitochondria.Trypanosoma brucei brucei is of medical and economic importance as the agent of human African sleeping sickness and nagana in cattle. The life cycle of the parasite in the mammalian host begins with metacyclic forms injected with the bite of the tsetse fly vector. These metacyclics subsequently transform into the rapidly dividing long slender forms which in turn give rise to intermediate and short stumpy forms, stages suggested to be pre-adapted to survive in the vector if ingested with a blood meal. In this report we refer to the intermediate and short stumpy bloodstream forms as transitional bloodstream forms. Several aspects of the metabolism of bloodstream 7: brucei brucei are known to be unique and have been identified as targets for chemotherapy (Fairlamb, 1989;Clarkson and Brohn, 1976). Of special interest is the mitochondrion which undergoes marked differentiation and development as the organism progresses through its life cycle (Vickerman, 1965). The procyclic or insect midgut form has cytochromes and Krebs cycle function whereas these are both reported to be absent in bloodstream form mitochondria which have high respiratory activity but a limited range of function (for review see Fairlamb and Opperdoes, 1976).Glycolysis is generally considered the sole source of ATP in all bloodstream forms. However, earlier work by Vickerman (1965) and Flynn and Bowman (1973) showed that populations with significant numbers of transitional bloodstream forms were able to maintain cell motility and oxygen utilization in the presence of 2-oxoglutarate, a Krebs cycle intermediate. In contrast, long slender fosms lysed in the absence of Correspo...

show abstract

Section: Methodsmentioning

confidence: 99%

Non‐cytochrome mediated mitochondrial ATP production in bloodstream form Trypanosoma brucei brucei

Ej¹,

Rk²,

Pollakis³

et al. 1993

European Journal of Biochemistry

View full text Add to dashboard Cite

show abstract

“…The mammalian bloodstream-form trypomastigotes (BFTs) generate their energy through glycolysis (12) and bear a uniform glycoprotein surface coat, whereas the insect procyclic trypomastigotes, which are biochemically, morphologically, and serologically indistinguishable from the forms grown in culture at 27°C (8), bear no recognizable surface coat and have fully developed mitochondrial respiration (5,6). The study of developmental regulation of gene expression in trypanosomes is of particular interest because of the novel mechanisms of transcription and RNA processing used by these organisms (reviewed in reference 7).…”

mentioning

confidence: 99%

Polymorphism in the procyclic acidic repetitive protein gene family of Trypanosoma brucei.

Mowatt

Clayton

1988

Mol. Cell. Biol.

View full text Add to dashboard Cite

The expression of procyclic acidic repetitive protein (PARP) by Trypanosoma brucei is strongly induced during the transition of bloodstream form to cultured procyclic trypomastigotes in vitro. The membrane-associated protein is distinguished by a central domain consisting of tandemly repeated glutamate-proline dipeptides. The trypanosome genome contains eight PARP genes, at least four of which are expressed. A minimum of four distinct PARP mRNA species comprises two classes of PARP mRNA, based upon divergent 3' untranslated region sequences, and these mRNAs encode polypeptides that exhibited an inverse relation between molecular weight and isoelectric point. Comparative analysis of PARP gene structure indicated that these polypeptides differ by variation in size of the dipeptide repeat domain. Comparison of PARP genes and polypeptides of three independent T. brucei isolates suggested that PARP is not a homogeneous species but instead represents a family of polymorphic proteins.

show abstract

“…The results indicated that there was no selective loss of mRNA during the bloodstream trypanosome RNA isolation procedure which would account for the signal variations observed with the cytochrome c probe. DISCUSSION Previous studies on Trypanosoma brucei have demonstrated that mitochondrial biogenesis is regulated during different developmental stages of the parasite (5,6,29). In particular, investigations done with respiratory inhibitors, such as cyanide, antimycin, and carbon monoxide, have shown that bloodstream forms of T. brucei lack the intact cytochrome-mediated respiratory chain present in the procyclic form (8,23).…”

Section: Resultsmentioning

confidence: 99%

“…These short stumpy trypanosomes are preadapted to life in the insect vector, where they differentiate into the early insect developmental stage, the procyclic trypanosomes (29,45). The bloodstream forms of T. brucei have an inactive mitochondrion which lacks cytochrome-mediated respiration (5,6,9,23). The procyclic form of T. brucei has a mitochondrion which is larger and has a more expansive network of cristae than is found in the bloodstream trypanosomes.…”

mentioning

confidence: 99%

Posttranscriptional regulation of cytochrome c expression during the developmental cycle of Trypanosoma brucei.

Torri¹,

Hajduk²

1988

Mol. Cell. Biol.

View full text Add to dashboard Cite

We examined the expression of a nucleus-encoded mitochondrial protein, cytochrome c, during the life cycle of Trypanosoma brucei. The bloodstream forms of T. brucei, the long slender and short stumpy trypanosomes, have inactive mitochondria with no detectable cytochrome-mediated respiration. The insect form of T. brucei, the procyclic trypanosomes, has fully functional mitochondria. Cytochrome c is spectrally undetectable in the bloodstream forms of trypanosomes, but during differentiation to the procyclic form, spectrally detected holo-cytochrome c accumulates rapidly. We have purified T. brucei cytochrome c and raised antibodies that react to both holo- and apo-cytochrome c. In addition, we isolated a partial cDNA to trypanosome cytochrome c. An examination of protein expression and steady-state mRNA levels in T. brucei indicated that bloodstream trypanosomes did not express cytochrome c but maintained significant steady-state levels of cytochrome c mRNA. The results suggest that in T. brucei, cytochrome c is developmentally regulated by a posttranscriptional mechanism which prevents either translation or accumulation of cytochrome c in the bloodstream trypanosomes.

show abstract

Elaboration of mitochondrial function during Trypanosoma brucei differentiation

Cited by 47 publications

References 17 publications

Non‐cytochrome mediated mitochondrial ATP production in bloodstream form Trypanosoma brucei brucei

Non‐cytochrome mediated mitochondrial ATP production in bloodstream form Trypanosoma brucei brucei

Polymorphism in the procyclic acidic repetitive protein gene family of Trypanosoma brucei.

Posttranscriptional regulation of cytochrome c expression during the developmental cycle of Trypanosoma brucei.

Contact Info

Product

Resources

About