cDNA of the 24 kDa subunit of the bovine respiratory chain NADH dehydrogenase: high sequence conservation in mammals and tissue-specific and growth-dependent expression

1989 ◽  
Vol 16 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Anne Chomyn ◽  
Susan S. -A. Tsai Lai
Author(s):  
Viktoriya V. Vorobyova ◽  
Olga S. Levchenkova ◽  
Petr D. Shabanov

Introduction. Modern technological processes that generate ultra- and infrasound, electromagnetic, vibration-noise radiation significantly exceed the background effects and inevitably create an unfavorable technogenic load on the human body. A special place is occupied by vibration, primarily associated with such professional groups as mining enterprises, gold and diamond processing plants, aircraft plants, thermal power plants and hydroelectric power plants, and aluminum industry enterprises. Vibration exposure leads to a number of biochemical disorders in the homeostasis system. Mitochondrial dysfunctions are among the leading elements in the hierarchy of pathogenesis of many pathological syndromes and diseases. The aim of the study was an experimental analysis of tissue-specific features of the myocardium, kidneys, liver energy production system activity as well as the enzyme status of rat lymphocytes in relation to the activity of succinate dehydrogenase (SDH) on the background of 7 episodes of local vibration with a frequency of 27-30 Hz for 90 minutes daily before and after protection with succinate-containing antihypoxant "Yantar-cardio" at a dose of 100 mg/kg/day. Materials and methods. The study of the energy-dependent reactions of the native mitochondria of the organs was carried out by the polarographic method using a closed Clark-type membrane electrode. The activity of SDH of rat blood lymphocytes was studied by a modified method of quantitative cytochemical analysis. Results. Functional rearrangement in the respiratory chain (RC) of the mitochondria confirmed the NAD-dependent site's inhibition and activation of the oxidation system of endogenous succinic acid, most pronounced in the myocardial tissue. On the vibration background, the specific SDH activity of lymphocytes (Q) significantly increased by 52%, and the variability (V) - by three times. The use of "Yantar-cardio" limited the growth rate of endogenous respiration of the most significant in the heart (70%, p<0.05), restored oxidative and conjugating activity NAD-dependent link of RC, improve the structure and condition of the cell population of lymphocytes based on their energy status and warned the mismatch of the leading parameters of the population variability of the cellular pool of blood lymphocytes in experimental animals. Conclusions. The intensity of vibration-mediated bioenergetic hypoxia in the form of inhibition of the NAD-dependent link of the respiratory chain and activation of the endogenous succinic acid oxidation system is tissue-specific and is most pronounced in the myocardial tissue. The succinic acid oxidation system is highly sensitive to vibration effects and a pharmacological drug that supports the function of RC under conditions of the stress of the homeostatic functions of tissues involved in the pathological process.


2021 ◽  
Author(s):  
Hannes Juergens ◽  
Álvaro Mielgo-Gómez ◽  
Albert Godoy-Hernández ◽  
Jolanda ter Horst ◽  
Janine M. Nijenhuis ◽  
...  

AbstractMitochondria from Ogataea parapolymorpha harbor a branched electron-transport chain containing a proton-pumping Complex I NADH dehydrogenase and three alternative (type II) NADH dehydrogenases (NDH2s). To investigate the physiological role, localization and substrate specificity of these enzymes, growth of various NADH dehydrogenase mutants was quantitatively characterized in shake-flask and chemostat cultures, followed by oxygen-uptake experiments with isolated mitochondria. Furthermore, NAD(P)H:quinone oxidoreduction of the three NDH2s were individually assessed. Our findings show that the O. parapolymorpha respiratory chain contains an internal NADH-accepting NDH2 (Ndh2-1/OpNdi1), at least one external NAD(P)H-accepting enzyme and likely additional mechanisms for respiration-linked oxidation of cytosolic NADH. Metabolic regulation appears to prevent competition between OpNdi1 and Complex I for mitochondrial NADH. With the exception of OpNdi1, the respiratory chain of O. parapolymorpha exhibits metabolic redundancy and tolerates deletion of multiple NADH-dehydrogenase genes without compromising fully respiratory metabolism.ImportanceTo achieve high productivity and yields in microbial bioprocesses, efficient use of the energy substrate is essential. Organisms with branched respiratory chains can respire via the energy-efficient proton-pumping Complex I, or make use of alternative NADH dehydrogenases (NDH2s). The yeast Ogataea parapolymorpha contains three uncharacterized, putative NDH2s which were investigated in this work. We show that O. parapolymorpha contains at least one ‘internal’ NDH2, which provides an alternative to Complex I for mitochondrial NADH oxidation, albeit at a lower efficiency. The use of this NDH2 appeared to be limited to carbon excess conditions and the O. parapolymorpha respiratory chain tolerated multiple deletions without compromising respiratory metabolism, highlighting opportunities for metabolic (redox) engineering. By providing a more comprehensive understanding of the physiological role of NDH2s, including insights into their metabolic capacity, orientation and substrate specificity this study also extends our fundamental understanding of respiration in organisms with branched respiratory chains.


Circulation ◽  
2003 ◽  
Vol 108 (19) ◽  
pp. 2423-2429 ◽  
Author(s):  
Dirk Lebrecht ◽  
Bernhard Setzer ◽  
Uwe-Peter Ketelsen ◽  
Jörg Haberstroh ◽  
Ulrich A. Walker

1968 ◽  
Vol 46 (9) ◽  
pp. 1003-1008 ◽  
Author(s):  
K. B. Freeman ◽  
D. Haldar

Chloramphenicol and its isomers and analogues have been found to inhibit the oxidation of NADH, but not that of succinate, by beef heart mitochondria. They must therefore inhibit the NADH dehydrogenase segment of the respiratory chain. Chloramphenicol gave 50% inhibition at a concentration of 1 mM. The methylthio analogue of chloramphenicol inhibited NADH – coenzyme Q6 reductase but not NADH–ferricyanide reductase. Spectrophotometric observations suggest that these inhibitors act between NADH and flavin in coupled rat liver mitochondria and between flavin and cytochrome b in uncoupled beef heart mitochondria.


2019 ◽  
Vol 7 (12) ◽  
pp. 640 ◽  
Author(s):  
Vojtěch Sedláček ◽  
Igor Kučera

Paracoccus denitrificans is a strictly respiring bacterium with a core respiratory chain similar to that of mammalian mitochondria. As such, it continuously produces and has to cope with superoxide and other reactive oxygen species. In this work, the effects of artificially imposed superoxide stress on electron transport were examined. Exposure of aerobically growing cells to paraquat resulted in decreased activities of NADH dehydrogenase, succinate dehydrogenase, and N,N,N’,N’-tetramethyl-p-phenylenediamine (TMPD) oxidase. Concomitantly, the total NAD(H) pool size in cells was approximately halved, but the NADH/NAD+ ratio increased twofold, thus partly compensating for inactivation losses of the dehydrogenase. The inactivation of respiratory dehydrogenases, but not of TMPD oxidase, also took place upon treatment of the membrane fraction with xanthine/xanthine oxidase. The decrease in dehydrogenase activities could be fully rescued by anaerobic incubation of membranes in a mixture containing 2-mercaptoethanol, sulfide and ferrous iron, which suggests iron–sulfur clusters as targets for superoxide. By using cyanide titration, a stress-sensitive contribution to the total TMPD oxidase activity was identified and attributed to the cbb3-type terminal oxidase. This response (measured by both enzymatic activity and mRNA level) was abolished in a mutant defective for the FnrP transcription factor. Therefore, our results provide evidence of oxidative stress perception by FnrP.


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