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@article{1593161, author = {Sedláček, Vojtěch and Kučera, Igor}, article_location = {Basel}, article_number = {12}, doi = {http://dx.doi.org/10.3390/microorganisms7120640}, keywords = {NADH dehydrogenase; succinate dehydrogenase; terminal oxidase; iron-sulfur cluster; FnrP transcription factor; superoxide}, language = {eng}, issn = {2076-2607}, journal = {Microorganisms}, title = {Modifications of the Aerobic Respiratory Chain of Paracoccus Denitrificans in Response to Superoxide Oxidative Stress}, url = {https://doi.org/10.3390/microorganisms7120640}, volume = {7}, year = {2019} }
TY - JOUR ID - 1593161 AU - Sedláček, Vojtěch - Kučera, Igor PY - 2019 TI - Modifications of the Aerobic Respiratory Chain of Paracoccus Denitrificans in Response to Superoxide Oxidative Stress JF - Microorganisms VL - 7 IS - 12 SP - 1-12 EP - 1-12 PB - MDPI SN - 20762607 KW - NADH dehydrogenase KW - succinate dehydrogenase KW - terminal oxidase KW - iron-sulfur cluster KW - FnrP transcription factor KW - superoxide UR - https://doi.org/10.3390/microorganisms7120640 L2 - https://doi.org/10.3390/microorganisms7120640 N2 - 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. ER -
SEDLÁČEK, Vojtěch and Igor KUČERA. Modifications of the Aerobic Respiratory Chain of Paracoccus Denitrificans in Response to Superoxide Oxidative Stress. \textit{Microorganisms}. Basel: MDPI, 2019, vol.~7, No~12, p.~1-12. ISSN~2076-2607. Available from: https://dx.doi.org/10.3390/microorganisms7120640.
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