Self-assembled light-driven photosynthetic-respiratory electron transport chain hybrid proton pump

2013 ◽  
Vol 4 (10) ◽  
pp. 3833 ◽  
Author(s):  
David Hvasanov ◽  
Joshua R. Peterson ◽  
Pall Thordarson
Keyword(s):  
Electron Transport ◽  
Proton Pump ◽  
Electron Transport Chain ◽  
Transport Chain ◽  
Self Assembled ◽  
Respiratory Electron Transport

scholarly journals Roles of Alanine Dehydrogenase and Induction of Its Gene inMycobacterium smegmatisunder Respiration-Inhibitory Conditions

2018 ◽  
Vol 200 (14) ◽  
Author(s):  
Ji-A Jeong ◽  
Sae Woong Park ◽  
Dahae Yoon ◽  
Suhkmann Kim ◽  
Ho-Young Kang ◽  
...  
Keyword(s):  
Electron Transport ◽  
Mycobacterium Smegmatis ◽  
Electron Transport Chain ◽  
Specific Inhibitor ◽  
Expression Level ◽  
Growth Defect ◽  
Content Type ◽  
Alanine Dehydrogenase ◽  
Transport Chain ◽  
Respiratory Electron Transport

ABSTRACTHere we demonstrated that the inhibition of electron flux through the respiratory electron transport chain (ETC) by either the disruption of the gene for the major terminal oxidase (aa3cytochromecoxidase) or treatment with KCN resulted in the induction ofaldencoding alanine dehydrogenase inMycobacterium smegmatis. A decrease in functionality of the ETC shifts the redox state of the NADH/NAD+pool toward a more reduced state, which in turn leads to an increase in cellular levels of alanine by Ald catalyzing the conversion of pyruvate to alanine with the concomitant oxidation of NADH to NAD+. The induction ofaldexpression under respiration-inhibitory conditions inM. smegmatisis mediated by the alanine-responsive AldR transcriptional regulator. The growth defect ofM. smegmatisby respiration inhibition was exacerbated by inactivation of thealdgene, suggesting that Ald is beneficial toM. smegmatisin its adaptation and survival under respiration-inhibitory conditions by maintaining NADH/NAD+homeostasis. The low susceptibility ofM. smegmatistobcc1complex inhibitors appears to be, at least in part, attributable to the high expression level of thebdquinol oxidase inM. smegmatiswhen thebcc1-aa3branch of the ETC is inactivated.IMPORTANCEWe demonstrated that the functionality of the respiratory electron transport chain is inversely related to the expression level of thealdgene encoding alanine dehydrogenase inMycobacterium smegmatis. Furthermore, the importance of Ald in NADH/NAD+homeostasis during the adaptation ofM. smegmatisto severe respiration-inhibitory conditions was demonstrated in this study. On the basis of these results, we propose that combinatory regimens including both an Ald-specific inhibitor and respiration-inhibitory antitubercular drugs such as Q203 and bedaquiline are likely to enable a more efficient therapy for tuberculosis.

The regulation of nitrate reduction in spinach leaves

1979 ◽  
Vol 57 (10) ◽  
pp. 1155-1160 ◽  
Author(s):  
David T. Canvin ◽  
K. C. Woo
Keyword(s):  
Electron Transport ◽  
Nitrate Reduction ◽  
Electron Transport Chain ◽  
Antimycin A ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Transport Chain ◽  
Respiratory Electron Transport ◽  
Spinach Leaves

Nitrate reduction did not occur in leaves in the dark in aerobic conditions but did occur in anaerobic conditions. Nitrate reduction in leaves in the dark in aerobic conditions was observed, however, when the respiratory electron transport chain was inhibited with antimycin A but not when it was inhibited with amytal or rotenone. It would appear that NADH generated outside the mitochondria was used for nitrate reduction in the dark under anaerobic conditions. The relevance of this observation to nitrate reduction in the light is discussed.

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