Nitrite uptake into red blood cells (RBCs) precedes its intracellular reactions with hemoglobin (Hb) that forms nitric oxide (NO) during hypoxia. We investigated the uptake of nitrite and its reactions with Hb at different oxygen saturations (So(2)), using RBCs with (carp and rabbit) and without (hagfish and lamprey) anion exchanger-1 (AE1) in the membrane, with the aim to unravel the mechanism...

The reduction of circulating nitrite to nitric oxide (NO) has emerged as an important physiological reaction aimed to increase vasodilation during tissue hypoxia. Although hemoglobin, xanthine oxidase, endothelial NO synthase, and the bc(1) complex of the mitochondria are known to reduce nitrite anaerobically in vitro, their relative contribution to the hypoxic vasodilatory response has remaine...

Nitrite reduction by a copper complex featuring a proton-responsive tripodal ligand is demonstrated. Gaseous nitric oxide was confirmed as the sole NO X by-product in quantitative yield. DFT calculations predict that nitrite reduction occurs via a proton and electron transfer process mediated by the ligand. The reported mechanism parallels nitrite reduction by copper nitrite reductase.

Background and Objectives. Presence of excessive nitrite and nitrate in foodstuff can have toxic and carcinogenic effects on humans. This study is aimed at measuring nitrate and nitrite in different foodstuffs available in Arak city market, Iran, in 2013. Methods. Totally 323 samples including stew (102 samples), beverage (116 samples), fruit (55 samples), and vegetables (50 samples) were rando...

Haloferax mediterranei is a denitrifying halophilic archaeon able to reduce nitrate and nitrite under oxic and anoxic conditions. In the presence of oxygen, nitrate and nitrite are used as nitrogen sources for growth. Under oxygen scarcity, this haloarchaeon uses both ions as electron acceptors via a denitrification pathway. In the present work, the maximal nitrite concentration tolerated by th...

Inorganic nitrate and nitrite from dietary and endogenous sources are metabolized to NO and other bioactive nitrogen oxides that affect blood pressure. The mechanisms for nitrite bioactivation are unclear, but recent studies in rodents suggest that gastric acidity may influence the systemic effects of this anion. In a randomized, double-blind, placebo-controlled crossover study, we tested the e...

Nitrite accumulation in shrimp ponds can pose serious adverse effects to shrimp production and the environment. This study aims to develop an effective process for the enrichment of ready-to-use nitrite-oxidizing bacteria (NOB) inocula that would be appropriate for nitrite removal in brackish shrimp ponds. To achieve this objective, the effects of nitrite concentrations on NOB communities and n...

Resting cells of Corynebacterium nephridii reduce nitrate, nitrite, and nitric oxide to nitrous oxide under anaerobic conditions. Nitrous oxide production from nitrite was optimal from pH 7.0 to 7.4. The stoichiometry of nitrous oxide production from nitrite was 99% of the theoretical-two moles of nitrite was used for each mole of nitrous oxide detected. Hydroxylamine increases gas evolution fr...

Reduction of nitrite by cell-free preparations of Anabaena cylindrica in the dark has been investigated. Nitrite-reducing activity was recovered in a supernatant fraction. The nitrite reductase system was partially purified by column chromatography on Sephadex G-75. NADPH could serve as an H-donor. NADH was completely inactive. The reduction required ferredoxin which mediated the transfer of el...

A simple, sensitive and rapid method for determination of trace amounts of nitrite ion in real samples is reported. The reaction is initiated by adding known volumes of a nitrite ion solution of identified concentration to acidic solutions of thionine which causes decolorizaiton of reagent with time. The absorbance changes is then monitored spectrophotometrically at l...