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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: Based on the on-line indirect measurements of DO and pH, the relationship between pH (or DO) and nitrogen concentration is investigated and indicates that pH and DO can be used as control parameters for the real-time aeration control strategy to obtain nitritation in SBR treating domestic wastewater.
112 citations
TL;DR: It is suggested that nitrification in this soil is a heterotrophic process catalyzed by acid-tolerant fungi and not by autotrophs or heterOTrophs in nonacid microsites.
Abstract: Nitrate was formed from ammonium at pH 3.2 to 6.1 in suspensions of a naturally acid forest soil; the maximum rates of formation occurred at ca. pH 4 to 5. Nitrate was also formed from soil nitrogen in suspensions incubated at 50 degrees C. Autotrophic nitrifying bacteria could not be isolated from this soil. Enrichment cultures produced nitrate in a medium with beta-alanine if much soil was added to the medium, and nitrite but not nitrate was formed in the presence of small amounts of soil. Nitrification by these enrichments was abolished by eucaryotic but not procaryotic inhibitors. A strain of Absidia cylindrospora isolated from this soil was found to produce nitrate and nitrite in a medium with beta-alanine at pH values ranging from 4.0 to 4.8. Nitrate production by A. cylindrospora required the presence of sterile soil. Free and bound hydroxylamine, hydroxamic acids, and primary aliphatic nitro compounds did not accumulate during the conversion of beta-alanine to nitrite by the fungus. The organism also formed nitrite from ammonium in a medium containing acetate. We suggest that nitrification in this soil is a heterotrophic process catalyzed by acid-tolerant fungi and not by autotrophs or heterotrophs in nonacid microsites.
112 citations
TL;DR: To measure the concentration of nitrites and nitrates by chemiluminescence, the efficiency of five reducing agents to reduce nitrite (NO2-) and (or) nitrate (NO3-) to nitric oxide (NO) was examined and recovery from plasma of both animals was reproducible and near quantitative.
Abstract: To measure the concentration of nitrites and nitrates by chemiluminescence, we examined the efficiency of five reducing agents [V(III), Mo(VI) + Fe(II), NaI, Ti(III), and Cr(III)] to reduce nitrite (NO2-) and (or) nitrate (NO3-) to nitric oxide (NO). The effect of each reducing agent on the conversion of different amounts of NO2- and (or) NO3- (100-500 pmol, representing concentrations of 0.4 to 2 mu molar) to NO was determined at 20 degrees C for NO2- and at 80 degrees C for NO3-. The effect of temperature from 20 to 90 degrees C on the conversion of a fixed amount of NO2- or NO3- (400 pmol or 1.6 mu molar) to NO was also determined. These five reducing agents are similarly efficient for the conversion of NO2- to NO at 20 degrees C. V(III) and Mo(VI) + Fe(II) can completely reduce NO3- to NO at 80 degrees C. NaI and Cr(III) were unable to convert NO3- to NO. Increased temperature facilitated the conversion of NO3- to NO, rather than that of NO2- to NO. We evaluated the recovery of NO2- and NO3- from plasmas of pig and of dog. Recovery from plasma of both animals was reproducible and near quantitative.
112 citations
TL;DR: Nitric oxide and the NO end products, nitrate and nitrite, were measured at the impact site after a 5-m/s, 3-mm deformation controlled cortical impact injury in rats.
Abstract: Nitric oxide (NO) and the NO end products, nitrate and nitrite, were measured at the impact site after a 5-m/s, 3-mm deformation controlled cortical impact injury in rats. Immediately after the imp...
112 citations
TL;DR: These findings strongly argue for the role of NO, or an oxygen species derived from it, in the activation reaction of methane.
Abstract: Nitric oxide (NO) and nitrous oxide (N2O) are among Nature’s most powerful electron acceptors. In recent years it became clear that microorganisms can take advantage of the oxidizing power of these compounds to degrade recalcitrant aliphatic and aromatic hydrocarbons. For two unrelated bacterial species, the ‘NC10’ phylum bacterium ‘Candidatus Methylomirabilis oxyfera’ and the γ-proteobacterial strain HdN1 it has been suggested that under anoxic conditions with nitrate and/or nitrite, monooxygenases are used for methane and hexadecane oxidation, respectively. No degradation was observed with nitrous oxide only. Similarly, “aerobic” pathways for hydrocarbon degradation are employed by (per)chlorate-reducing bacteria, which are known to produce oxygen from chlorite (ClO2-). In the anaerobic methanotroph M. oxyfera, which lacks identifiable enzymes for nitrogen formation, substrate activation in the presence of nitrite was directly associated with both oxygen and nitrogen formation. These findings strongly argue for the role of NO, or an oxygen species derived from it, in the activation reaction of methane. Although oxygen generation elegantly explains the utilization of ‘aerobic’ pathways under anoxic conditions, the underlying mechanism is still elusive. In this perspective we review the current knowledge about intra-aerobic pathways, their potential presence in other organisms and identify candidate enzymes related to quinol-dependent NO reductases (qNORs) that might be involved in the formation of oxygen.
112 citations