Nitrate, a compound of low toxicity, when ingested orally, is absorbed from the gastrointestinal tract in its free form. About 20-28% of this is then secreted into saliva and only 4-8% of the ingested nitrate is converted into nitrite by nitrate reducing bacteria. The resulting nitrite is then further reduced to nitric oxide by the same bacteria [1-3]. Many studies have related the beneficial e...

Neisseria meningitidis, the causative agent of meningococcal disease in humans, is likely to be exposed to nitrosative stress during natural colonization and disease. The genome of N. meningitidis includes the genes aniA and norB, predicted to encode nitrite reductase and nitric oxide (NO) reductase, respectively. These gene products should allow the bacterium to denitrify nitrite to nitrous ox...

Nitrite was formed from hydroxylamine and several oximes by intact cells and extracts of Pseudomonas aeruginosa. The activity was induced by the presence of oximes in the culture medium. Nitroalkanes were not intermediates in the conversion of acetaldoxime, acetone oxime, or butanone oxime to nitrite, since nitromethane inhibited the formation of nitrite from the nitro compounds but not from th...

2 Abstract Nitrite in/on the skin has potent antimicrobial effects and is believed to act as a local nitric oxide (NO) reservoir capable of modulating dermal cell function. Using male Wistar rats we here show that nitrite, when applied in neutral aqueous solution to the skin surface, readily permeates the dermis to reach the systemic circulation and cause widespread nitros(yl)ation of tissue pr...

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...

A method for the spectrophotometric determination of nitric oxide, nitrite, and nitrate in tissue culture media is presented. The method is based on the nitric oxide-mediated nitrosative modification of sulfanilic acid that reacts with N-(1-naphthyl)ethylenediamine dihydrochloride forming an orange-colored product absorbing at 496 nm. Nitric oxide levels were determined in culture media from th...

BACKGROUND In humans, high concentrations of nitric oxide are generated luminally at the gastro-oesophageal junction through enterosalivary recirculation of dietary nitrate. AIM To investigate whether luminal nitric oxide can diffuse into the adjacent digestive tissue and alter tissue integrity. METHODS We designed an animal model using Wistar rats in which physiological concentrations of n...

Nitrous oxide can be a harmful by-product in nitrogen removal from wastewater. Since wastewater treatment systems operate under different aeration regimens, the influence of different oxygen concentrations and oxygen fluctuations on denitrification was studied. Continuous cultures of Alcaligenes faecalis TUD produced N2O under anaerobic as well as aerobic conditions. Below a dissolved oxygen co...

Shewanella exhibit a remarkable versatility of respiration, with a diverse array of electron acceptors (EAs). In environments where these bacteria thrive, multiple EAs are usually present. However, we know little about strategies by which these EAs and their interaction affect ecophysiology of Shewanella. In this study, we demonstrate in the model strain, Shewanella oneidensis MR-1, that nitrit...

The rpoN region of Pseudomonas stutzeri was cloned, and an rpoN null mutant was constructed. RpoN was not essential for denitrification in this bacterium but affected the expression levels and enzymatic activities of cytochrome cd1 nitrite reductase and nitric oxide reductase, whereas those of respiratory nitrate reductase and nitrous oxide reductase were comparable to wild-type levels. Since t...