The relationship between the in situ reduction level of the cytochrome c pool of Azorhizobium caulinodans growing in a chemostat with NH4+ or N2 as the N source and the total activity of cytochrome c oxidases |
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| Authors: | Annemieke F Pronk Charles Affourtit Cyril Mashingaidze Adriaan H Stouthamer Henk W van Verseveld Fred C Boogerd |
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| Institution: | Department of Microbiology, Institute for Molecular Biological Sciences, Biocentrum Amsterdam, Vrije Universiteit, De Boelelaan 1087,1081 HV Amsterdam, the Netherlands |
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| Abstract: | Abstract The in situ method for determination of reduction levels of cytochromes b and c pools during steady-state growth (Pronk et al., Anal. Biochem. 214, 149–155, 1993) was applied to chemostat cultures of the wild-type, a cytochrome aa3 single mutant and a cytochrome aa3/d double mutant of Azorhizobium caulinodans . For growth with NH4+ as the N source, the results indicate that (i) the aa3 mutant strains growing at a dissolved O2 tension of 0.5% possess an active alternative cytochrome c oxidase, which is hardly present during fully aerobic growth, and assuming that (i) also pertains to the wild-type, (ii) the wild-type uses cytochrome aa3 under fully aerobic conditions. For growth with N2 as the N source, it was found that the aa3 mutant strains growing at dissolved O2 tensions ranging from 0.5 to 3.0% also contain an active alternative cytochrome c oxidase. |
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| Keywords: | Oxygen Cytochrome c oxidase activity Cytochrome c Cytochrome reduction level Chemostat Azorhizobium caulinodans |
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