Topic
Nitrite
About: Nitrite is a research topic. Over the lifetime, 15425 publications have been published within this topic receiving 484581 citations.
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TL;DR: The nitrogen removal performance of an anaerobic biological filtrated (ABF) reactor, filled with porous polyester nonwoven fabric carriers as a fixed bed for anammox bacteria, was tested at moderately low temperature and showed that an appropriate nitrite concentration in the influent and a shorter HRT resulted in high nitrogen conversion rates.
174 citations
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TL;DR: The results are consistent with a model in which NO is a freely diffusible intermediate between nitrite and N2O, providing that nitric oxide reductase is or nearly is a diffusion controlled enzyme.
174 citations
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TL;DR: In this paper, the reduction of nitrate and nitrite anions was investigated on pyrolytic graphite electrodes prepared by potentiostatic electrodeposition with the use of a double-pulse technique.
174 citations
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TL;DR: It is demonstrated that conversion of nitrite to NO by blood vessels and RBCs was enhanced in the presence of the Xor substrate xanthine and attenuated by the XOR inhibitor allopurinol in acidic and hypoxic conditions only.
Abstract: Reduction of nitrite (NO(2)(-)) provides a major source of nitric oxide (NO) in the circulation, especially in hypoxemic conditions. Our previous studies suggest that xanthine oxidoreductase (XOR) is an important nitrite reductase in the heart and kidney. Herein, we have demonstrated that conversion of nitrite to NO by blood vessels and RBCs was enhanced in the presence of the XOR substrate xanthine (10 micromol/L) and attenuated by the XOR inhibitor allopurinol (100 micromol/L) in acidic and hypoxic conditions only. Whereas endothelial nitric oxide synthase (eNOS) inhibition had no effect on vascular nitrite reductase activity, in RBCs L-NAME, L-NMMA, and L-arginine inhibited nitrite-derived NO production by >50% (P<0.01) at pH 7.4 and 6.8 under hypoxic conditions. Western blot and immunohistochemical analysis of RBC membranes confirmed the presence of eNOS and abundant XOR on whole RBCs. Thus, XOR and eNOS are ideally situated on the membranes of RBCs and blood vessels to generate intravascular vasodilator NO from nitrite during ischemic episodes. In addition to the proposed role of deoxyhemoglobin, our findings suggest that the nitrite reductase activity within the circulation, under hypoxic conditions (at physiological pH), is mediated by eNOS; however, as acidosis develops, a substantial role for XOR becomes evident.
173 citations
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TL;DR: Results obtained in continuous stirred‐tank reactors (CSTR) operated at pH values between 6.6 and 7.8 showed that growth inhibition depended only on the nitrite undissociated fraction concentration (nitrous acid), and adapted cultures (grown on CSTR) are less sensitive to nitrous acid inhibition than the ones cultivated in batch.
Abstract: Using a pure culture of Pseudomonas fluorescens as a model system nitrite inhibition of denitrification was studies. A mineral media with acetate and nitrate as sole electron donor and acceptor, respectively, was used. Results obtained in continuous stirred-tank reactors (CSTR) operated at pH values between 6.6 and 7.8 showed that growth inhibition depended only on the nitrite undissociated fraction concentration (nitrous acid). A mathematical model to describe this dependence is put forward. The maximum nitrous acid concentration compatible with cell growth and denitrification activity was found to be 66 mug N/L. Denitrification activity was partially associated with growth, as described by the Luedeking-Piret equation. However, when the freshly inoculated reactor was operated discontinuosly, nitrite accumulation caused growth uncoupling from denitrification activity. The authors suggest that these results can be interpreted considering that (a) nitrous acid acts as a proton uncoupler; and (b) cultures continuoulsy exposed to nitrous acid prevent the uncoupling effect but not the growth inhibition. Examination of the growth dependence on nitrite concentration at pH 7.0 showed that adapted cultures (grown on CSTR) are less sensitive to nitrous acid inhibition than the ones cultivated in batch. (c) 1995 John Wiley & Sons, Inc.
173 citations