Novel Characteristics of Mitochondrial Electron Transport Chain from Eimeria tenella

Abstract

Eimeria tenella is an intracellular apicomplexan parasite, which infects cecal epithelial cells from chickens and causes hemorrhagic diarrhea and eventual death. We have previously reported the comparative RNA sequence analysis of the E. tenella sporozoite stage between virulent and precocious strains and showed that the expression of several genes involved in mitochondrial electron transport chain (ETC), such as type II NADH dehydrogenase (NDH-2), complex II (succinate:quinone oxidoreductase), malate:quinone oxidoreductase (MQO), and glycerol-3-phosphate dehydrogenase (G3PDH), were upregulated in virulent strain. To study E. tenella mitochondrial ETC in detail, we developed a reproducible method for preparation of mitochondria-rich fraction from sporozoites, which maintained high specific activities of dehydrogenases, such as NDH-2 followed by G3PDH, MQO, complex II, and dihydroorotate dehydrogenase (DHODH). Of particular importance, we showed that E. tenella sporozoite mitochondria possess an intrinsic ability to perform fumarate respiration (via complex II) in addition to the classical oxygen respiration (via complexes III and IV). Further analysis by high-resolution clear native electrophoresis, activity staining, and nano-liquid chromatography tandem-mass spectrometry (nano-LC-MS/MS) provided evidence of a mitochondrial complex II-III-IV supercomplex. Our analysis suggests that complex II from E. tenella has biochemical features distinct to known orthologues and is a potential target for the development of new anticoccidian drugs.

Complexome profile ofToxoplasma gondiimitochondria identifies a divergent cytochromebc1complex

“…The SDHB subunit migrated at ∼500 kDa in our complexome ( Figure 2D ), significantly larger than the 130 kDa complex seen in mammals and yeast [39]. Native PAGE and immunoblotting of the triple-HA epitope tagged SDHB subunit confirmed this finding ( Figure 3C ), which is also in line with a recent study of the apicomplexan Eimeria tenella [42]. The mammalian complex contains two other subunits, SDHC and SDHD, which function as hydrophobic membrane anchors.…”

“…In our complexome analysis, we found the FeS-containing subunit B (SDHB) to migrate at ∼500 kDa, with its highest abundance in slice 18 ( Figure 2D, S2C, D, Table S4 ). This size is much larger than for the mammalian and yeast complexes (130 kDa) [39], but in line with a the similarly large complex of 745 kDa recently proposed for the apicomplexan Eimeria tenella [42]. The SDHA subunit profile showed two peaks, one of which coincided with SDHB from Toxoplasma , and the other with the known C. sabaeus complex II subunits.…”

Complexome profile of Toxoplasma gondii mitochondria identifies divergent subunits of respiratory chain complexes including new subunits of cytochrome bc1 complex

“…In our complexome analysis, we found the FeS-containing subunit B (SDHB) to migrate at~500 kDa, with its highest abundance in slice 18 (Figs 2D, S2C and S2D and S5 Table). This size is much larger than for the mammalian and yeast complexes (~130 kDa) [37,43], but in line with a the similarly large complex of 745 kDa recently proposed for the apicomplexan Eimeria tenella [46]. The SDHA subunit profile showed two peaks, one of which coincided with SDHB from Toxoplasma, and the other with the known C. sabaeus complex II subunits.…”

Structural and Biochemical Features of Eimeria tenella Dihydroorotate Dehydrogenase, a Potential Drug Target

“…Due to the high economic impact of coccidiosis in the poultry industry, we performed the first characterization of the mitochondrial ETC from E. tenella sporozoites [55]. At the sporozoite stage, this parasite showed very high activity for enzymes of the ETC, with the exception of DHODH.…”