scholarly journals Alterations in the supramolecular interactions of respiratory chain complexes and enhanced superoxide production by the cytochrome b Y278C mutation which causes a multisystem disorder

2012 ◽  
Vol 1817 ◽  
pp. S139 ◽  
Author(s):  
A. Ghelli ◽  
C.V. Tropeano ◽  
M.A. Calvaruso ◽  
A. Marchesini ◽  
L. Iommarini ◽  
...  
Keyword(s):  
Cytochrome B ◽  
Respiratory Chain ◽  
Superoxide Production ◽  
Supramolecular Interactions ◽  
Multisystem Disorder ◽  
Respiratory Chain Complexes ◽  
Chain Complexes

scholarly journals The cytochrome b p.278Y>C mutation causative of a multisystem disorder enhances superoxide production and alters supramolecular interactions of respiratory chain complexes

2013 ◽  
Vol 22 (11) ◽  
pp. 2141-2151 ◽  
Author(s):  
Anna Ghelli ◽  
Concetta V. Tropeano ◽  
Maria Antonietta Calvaruso ◽  
Alessandra Marchesini ◽  
Luisa Iommarini ◽  
...  
Keyword(s):  
Cytochrome B ◽  
Respiratory Chain ◽  
Superoxide Production ◽  
Supramolecular Interactions ◽  
Multisystem Disorder ◽  
Respiratory Chain Complexes ◽  
Chain Complexes

scholarly journals Assembly factors monitor sequential hemylation of cytochrome b to regulate mitochondrial translation

2014 ◽  
Vol 205 (4) ◽  
pp. 511-524 ◽  
Author(s):  
Markus Hildenbeutel ◽  
Eric L. Hegg ◽  
Katharina Stephan ◽  
Steffi Gruschke ◽  
Brigitte Meunier ◽  
...  
Keyword(s):  
Electron Transport ◽  
Cytochrome B ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Mitochondrial Translation ◽  
Respiratory Chain Complexes ◽  
Mitochondrial Inner Membrane ◽  
Sequence Of Events ◽  
Chain Complexes ◽  
Assembly Factors

Mitochondrial respiratory chain complexes convert chemical energy into a membrane potential by connecting electron transport with charge separation. Electron transport relies on redox cofactors that occupy strategic positions in the complexes. How these redox cofactors are assembled into the complexes is not known. Cytochrome b, a central catalytic subunit of complex III, contains two heme bs. Here, we unravel the sequence of events in the mitochondrial inner membrane by which cytochrome b is hemylated. Heme incorporation occurs in a strict sequential process that involves interactions of the newly synthesized cytochrome b with assembly factors and structural complex III subunits. These interactions are functionally connected to cofactor acquisition that triggers the progression of cytochrome b through successive assembly intermediates. Failure to hemylate cytochrome b sequesters the Cbp3–Cbp6 complex in early assembly intermediates, thereby causing a reduction in cytochrome b synthesis via a feedback loop that senses hemylation of cytochrome b.

Relationships between the activity of respiratory-chain complexes in pre- (biopsy) or post-slaughter muscle samples and feed efficiency in random-bred Ghezel lambs

2017 ◽  
Vol 57 (8) ◽  
pp. 1674
Author(s):  
M. J. Zamiri ◽  
R. Mehrabi ◽  
G. R. Kavoosi ◽  
H. Rajaei Sharifabadi
Keyword(s):  
Respiratory Chain ◽  
Feed Intake ◽  
Enzyme Activities ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Chain Complex ◽  
Respiratory Chain Complex ◽  
Respiratory Chain Complexes ◽  
Chain Complexes ◽  
Daily Gain

The present study was conducted to determine the relationship between the activity of mitochondrial respiratory chain complexes in pre- and post-slaughter muscle samples and residual feed intake (RFI) in Ghezel male lambs born as a result of random mating. The study was based on the hypothesis that random-bred lambs with lower feed (or higher) RFI have lower (or higher) respiratory chain-complex activity in muscle samples. Lambs (n = 30) were fed a diet consisting of 70% concentrate and 30% alfalfa hay during a 70-day period. Individual feed intake and average daily gain were recorded to calculate the RFI, feed-conversion ratio (FCR) and adjusted FCR (aFCR). On the basis of these calculations, the lambs were classified into low and high groups for RFI, with FCR and aFCR (n = 22) being one standard deviation above or below the means; this was corroborated by Student’s t-test (P < 0.01). At the end of the experiment, a 10-g biopsy sample was taken from the posterior side of the left femoral biceps. After 24 h, the lambs were slaughtered, and a sample from the posterior side of the right femoral biceps was dissected for determination of mitochondrial protein and respiratory chain-complex activities (Complexes I–V). The RFI was not correlated with the metabolic bodyweight and average daily gain, but was positively correlated (r = 0.56) with the average daily feed intake (P < 0.01); mean daily feed intake in the low-RFI group was 200 g less than that in the high-RFI group. The FCR and aFCR were not significantly (P > 0.05) correlated with average daily feed intake (r = 0.39 and r = 0.36 respectively), but showed a negative correlation (P < 0.01) with average daily gain (r = –0.73 and r = –0.76 respectively). Although very high negative correlations were recorded between the activities of all five respiratory-chain complexes and RFI in muscle samples obtained before (–0.91 to –0.97) and after (–0.92 to –0.97) slaughter, Complexes I and V showed small negative correlations (–0.40) with FCR or aFCR (P < 0.05). Enzyme activities of the respiratory-chain Complexes I, III and V were not significantly different between the pre- and post-slaughter biopsy samples; however, the enzyme activities of respiratory-chain Complexes II and IV were slightly higher in post-slaughter samples (P < 0.01). These results suggested that it may be possible to use the enzymatic activity of respiratory-chain complexes in muscle biopsy samples for screening of lambs for RFI, providing a useful procedure for genetic selection of lambs for this component of feed efficiency. These encouraging results need to be verified in further experiments using other sheep breeds and a larger number of lambs.

Enzymatic and Polarographic Measurements of the Respiratory Chain Complexes

1999 ◽  
pp. 357-377 ◽  
Author(s):  
M. Malgat ◽  
T. Letellier ◽  
G. Durrieu ◽  
J.-P. Mazat
Keyword(s):  
Respiratory Chain ◽  
Respiratory Chain Complexes ◽  
Chain Complexes
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