The Neurospora crassa assimilatory nitrite reductase (EC 1.6.6.4) catalyzes the NADPH-dependent reduction of nitrite to ammonia, a 6-electron transfer reaction. Highly purified preparations of this enzyme exhibit absorption spectra which suggest the presence of a heme component (wavelength maxima for oxidized senzyme: 390 and 578 nm). There is a close correspondence between nitrite reductase ac...

The chemoautotrophic bacterium, Nitrosomonas europaea, derives its energy from the oxidation of ammonia to nitrite. Several investigators have noted that the ability to oxidize ammonia is entirely lost upon rupture of the Nitrosomonas cell, and that, although cell-free preparations retain a small fraction of the hydroxylamine-oxidizing activity, only 30 to 70% of the total hydroxylamine that is...

A Desulfovibrio vulgaris Hildenborough mutant lacking the nrfA gene for the catalytic subunit of periplasmic cytochrome c nitrite reductase (NrfHA) was constructed. In mid-log phase, growth of the wild type in medium containing lactate and sulfate was inhibited by 10 mM nitrite, whereas 0.6 mM nitrite inhibited the nrfA mutant. Lower concentrations (0.04 mM) inhibited the growth of both mutant ...

It is well known that nitrate is an important nutrient that supports plant growth and development. The application of nitrate also causes extensive changes in the expression of genes coding for proteins involved in nitrogen (N) metabolism. Indeed, genomic analyses have provided a comprehensive dataset of more than a thousand nitrate-responsive genes in Arabidopsis (Arabidopsis thaliana). Much l...

background: spinach is one of the vegetables with a high concentration of nitrate which is affected by various processes such as cooking and refrigeration before consumption. the present study aimed to investigate the effect of home cooking method, which has not been studied before, on the level of nitrate and nitrite in spinach. the effect of refrigeration was studied, as well.   methods: afte...

nitric oxide (no) is a molecule required for many physiological functions, produced from l-arginine by no synthases (nos). it is a free radical, producing many reactive intermediates that account for its bioactivity. sustained induction of the inducible form of nos (inos) in chronic inflammation may be mutagenic, through no-mediated dna damage or hindrance to dna repair, and thus potentially ca...

BACKGROUND Nitrite is a nitric oxide (NO) metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet a...

To understand the effects of physicochemical factors on nitrite transformation by microalgae, a lipid-rich Chlorella with high nitrite tolerance was cultured with 8 mmol/l sodium nitrite as sole nitrogen source under different conditions. The results showed that nitrite transformation was mainly dependent on the metabolic activities of algal cells rather than oxidation of nitrite by dissolved o...

Background and aims: Nitric oxide represents a potential key mediator of the local and systemic manifestations of acute pancreatitis (AP) in experimental models but its role in human disease is uncertain. We therefore sought to assess if systemic nitric oxide (NO) production is elevated in severe AP and determine whether this is a reflection of biochemical severity or endotoxin exposure. Patien...

This study examines the effect of antimycin A and nitrite on (14)CO(2) fixation in intact chloroplasts isolated from spinach (Spinacia oleracea L.) leaves. Antimycin A (2 micromolar) strongly inhibited CO(2) fixation but did not appear to inhibit or uncouple linear electron transport in intact chloroplasts. The addition of small quantities (40-100 micromolar) of nitrite or oxaloacetate, but not...