Transcription and activities of NOx reductases in Agrobacterium tumefaciens: the influence of nitrate, nitrite and oxygen availability
Open Access
- 30 September 2008
- journal article
- Published by Wiley in Environmental Microbiology
- Vol. 10 (11), 3070-3081
- https://doi.org/10.1111/j.1462-2920.2007.01557.x
Abstract
The ability of Agrobacetrium tumefaciens to perform balanced transitions from aerobic to anaerobic respiration was studied by monitoring oxygen depletion, transcription of nirK and norB, and the concentrations of nitrite, nitric oxide (NO) and nitrous oxide in stirred batch cultures with different initial oxygen, nitrate or nitrite concentrations. Nitrate concentrations (0.2–2 mM) did not affect oxygen depletion, nor the oxygen concentration at which denitrification was initiated (1–2 μM). Nitrite (0.2–2 mM), on the other hand, retarded the oxygen depletion as it reached ≈20 μM, and caused initiation of active denitrification as oxygen concentrations reached 10–17 μM. Unbalanced transitions occurred in treatments with high cell densities (i.e. with rapid transition from oxic to anoxic conditions), seen as NO accumulation to μM concentrations and impeded nitrous oxide production. This phenomenon was most severe in nitrite treatments, and reduced the cells' ability to respire oxygen during subsequent oxic conditions. Transcripts of norB were only detectable during the period with active denitrification. In contrast, nirK transcripts were detected at low levels both before and after this period. The results demonstrate that the transition from aerobic to anaerobic metabolism is a regulatory challenge, with implications for survival and emission of trace gases from denitrifying bacteria.Keywords
This publication has 42 references indexed in Scilit:
- Agrobacterium tumefaciens C58 Uses ActR and FnrN To Control nirK and nor ExpressionJournal of Bacteriology, 2008
- Robotized incubation system for monitoring gases (O2, NO, N2O N2) in denitrifying culturesJournal of Microbiological Methods, 2007
- Dissimilatory Metabolism of Nitrogen Oxides in Bacteria: Comparative Reconstruction of Transcriptional NetworksPLoS Computational Biology, 2005
- Comparison of two standardisation methods in real-time quantitative RT-PCR to follow Staphylococcus aureus genes expression during in vitro growthJournal of Microbiological Methods, 2004
- Fine-tuned regulation by oxygen and nitric oxide of the activity of a semi-synthetic FNR-dependent promoter and expression of denitrification enzymes in Paracoccus denitrificansMicrobiology, 2003
- Analysis of Relative Gene Expression Data Using Real-Time Quantitative PCR and the 2−ΔΔCT MethodMethods, 2001
- Nitrite–dependent nitric oxide production pathway: implications for involvement of active nitrogen species in photoinhibitionin vivoPhilosophical Transactions Of The Royal Society B-Biological Sciences, 2000
- The nitrite reductase gene of Pseudomonas aeruginosa: Effect of growth conditions on the expression and construction of a mutant by gene disruptionFEMS Microbiology Letters, 1993
- Nitric oxide formed by nitrite reductase of Paracoccus denitrificans is sufficiently stable to inhibit cytochrome oxidase activity and is reduced by its reductase under aerobic conditionsBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1990
- The Kinetics of the Synthesis of Photopigments in Rhodopseudomonas spheroidesJournal of General Microbiology, 1962