Nitrite is an intermediate in the oxidation of ammonium to nitrate. An elevated ambient nitrite concentration is a potential problem for freshwater fish since nitrite is actively taken up across the gills in competition with chloride. Nitrite is a well-known toxicant for fish as well as a disrupter of multiple physiological functions including ion regulatory, respiratory, cardiovascular, endocr...

In anaerobic enrichment cultures for phototrophic nitrite-oxidizing bacteria from different freshwater sites, two different cell types, i.e. non-motile cocci and motile, rod-shaped bacteria, always outnumbered all other bacteria. Most-probable-number (MPN) dilution series with samples from two freshwater sites yielded only low numbers (<or=3x10(3) cm(-3)) of phototrophic nitrite oxidizers. Slig...

Nitric oxide (NO) appears to play an important role in the regulation of thrombosis and hemostasis by inhibiting platelet function. The discovery of NO generation by reduction of nitrite (NO₂⁻) and nitrate (NO₃⁻) in mammals has led to increased attention to these anions with respect to potential beneficial effects in cardiovascular diseases. We have previously shown that nitrite anions at 0.1 µ...

In normal conditions, nitric oxide (NO) is oxidized to the anion nitrite, but in hypoxia, this nitrite may be reduced back to NO by the nitrite reductase action of deoxygenated hemoglobin, acidic disproportionation, or xanthine oxidoreductase (XOR). Herein, is investigated the effects of topical sodium nitrite administration in a rat model of renal ischemia/reperfusion (I/R) injury. Rats were s...

Nitrite reductases (NiRs) are enzymes found in prokaryotic organisms which catalyze the one-electron (e ) reduction of nitrite to nitric oxide (NO). Copper nitrite reductases (CuNiRs) are homotrimeric enzymes with each monomer containing two copper centers: a T1 site for electron transfer, and a catalyticallyactive T2 site. Although X-ray crystallographic studies have provided structural snapsh...

Salivary nitrate from dietary or endogenous sources is reduced to nitrite by oral bacteria. In the acidic stomach, nitrite is further reduced to bioactive nitrogen oxides, including nitric oxide (NO). In this study, we investigated the gastroprotective role of nitrate intake and of luminally applied nitrite against provocation with diclofenac and taurocholate. Mucosal permeability ((51)Cr-EDTA ...

Nitrite reacts with deoxyhemoglobin to generate nitric oxide (NO). This reaction has been proposed to contribute to nitrite-dependent vasodilation in vivo and potentially regulate physiological hypoxic vasodilation. Paradoxically, while deoxyhemoglobin can generate NO via nitrite reduction, both oxyhemoglobin and deoxyhemoglobin potently scavenge NO. Furthermore, at the very low O(2) tensions r...

the general objective of this study was to develop a highly efficient, economical andintegrated technology for the removal of nitrogen compounds through denitrification via nitrite. toachieve this, a modified uasb reactor was designed, set-up and operated using chilean zeolite asmicrobial support. the results were compared to a conventional uasb reactor used as control. thevolume of each reacto...

Kessler (1) has studied the reduction of nitrite to ammonia by the green alga Ankistrodesmus both in the light in an atmosphere of nitrogen and in the dark under hydrogen. No specific conclusion could be drawn as to the mechanism of the process, although it was assumed that reduced pyridine nucleotides might serve as the immediate hydrogen donors for the reduction of nitrite and that energy-ric...