Fig 5 - uploaded by Mary Rooney
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CoQ (ubiquinone) activity, measured by combined complex activities, among MSTN genotype (CC/II, CT/IN, TT/NN) horses. NADH cytochrome c oxidoreductase (Complex I + III) (A and C) and Succinate cytochrome c reductase (Complex II + III) (B and D) activities were measured spectrophotometrically on whole skeletal muscle homogenates (A) CC/II: n = 29, CT/IN: n = 28 and TT/NN: n = 7, (B) CC/II: n = 37, CT/IN: n = 32 and TT/NN: n = 11, (C) CC/II: n = 29, CT/IN: n = 28 and TT/NN: n = 7, and (D) CC/II: n = 33, CT/IN: n = 28 and TT/NN: n = 7, all performed in at least duplicate. CI+III (A) and CII+III (B) activities are an indirect measure of CoQ (ubiquinone). CI+III (C) and CII+III (D) activities were measured in the presence of supplementary CoQ 1 (Ubiquinone 1 ), demonstrating the relative complex activity deficiency is due to lower levels of endogenous CoQ. Results presented with mean ± SEM, p-values where shown indicate significance as measured by a one-way ANOVA with a Bonferroni multiple comparison post-test, * = p 0.05, ** = p 0.01, *** = p 0.001. https://doi.org/10.1371/journal.pone.0186247.g005
Contexts in source publication
Context 1
... combined enzyme activities of complex I+III and complex II+III were measured, normalized to mitochondrial abundance (CS activity) to determine the specific complex activity per unit mass of mitochondria and compared among genotypes. There were significantly lower levels of both combined complex I+III (Fig 5A) and complex II+III ( Considering that the individual activities of complex I, II and III appeared to be unaffected by genotype the differences in the activities of the combined complexes suggested there may be lower levels of CoQ in the mitochondria of skeletal muscle tissue of TT/NN horses compared to CC/II. CoQ 10 (ubiquinone (oxidized from) or ubiquinol (reduced form)) acts as a mobile redox carrier linking complex I and II with complex III in the electron transport chain of mitochondria. ...
Context 2
... to test the hypothesis that the combined complex activities were lower in TT/NN horses as a result of lower endogenous CoQ availability we conducted an 'add-back' experiment by adding CoQ 1 (or ubiquinone 1 ) to the complex I+III and complex II+III assays. The addition of ubiquinone restored the activity of complex I+III and complex II+III in the TT/NN horses to similar levels measured in the CC/II horses, indicating the difference in complex activity was due to a relative deficiency in endogenous CoQ in TT/NN horses (Fig 5C and 5D). ...
Citations
... This data was presented, in part, as a submitted abstract [90] and poster presentation at the ...
Variation in the myostatin (MSTN) gene has been reported to be associated with race distance, body composition and skeletal muscle fibre composition in the horse. The aim of the present study was to test the hypothesis that MSTN variation influences mitochondrial phenotypes in equine skeletal muscle. Mitochondrial abundance and skeletal muscle fibre types were measured in whole muscle biopsies from the gluteus medius of n = 82 untrained (21 ± 3 months) Thoroughbred horses. Skeletal muscle fibre type proportions were significantly (p < 0.01) different among the three MSTN genotypes and mitochondrial content was significantly (p < 0.01) lower in the combined presence of the C-allele of SNP g.66493737C>T (C) and the SINE insertion 227 bp polymorphism (I). Evaluation of mitochondrial complex activities indicated higher combined mitochondrial complex I+III and II+III activities in the presence of the C-allele / I allele (p ≤ 0.05). The restoration of complex I+III and complex II+III activities following addition of exogenous coenzyme Q1 (ubiquinone1) (CoQ1) in vitro in the TT/NN (homozygous T allele/homozygous no insertion) cohort indicated decreased coenzyme Q in these animals. In addition, decreased gene expression in two coenzyme Q (CoQ) biosynthesis pathway genes (COQ4, p ≤ 0.05; ADCK3, p ≤ 0.01) in the TT/NN horses was observed. This study has identified several mitochondrial phenotypes associated with MSTN genotype in untrained Thoroughbred horses and in addition, our findings suggest that nutritional supplementation with CoQ may aid to restore coenzyme Q activity in TT/NN horses.
