Most denitrifying bacteria reduce nitrate to the inert gases nitrous oxide or nitrogen. A remarkable exception to this is Rhizobium sullae strain HCNT1, which catalyses only a single step in the denitrification pathway, the reduction of nitrite to the reactive molecule nitric oxide. Further study demonstrated that HCNT1 does not encode the genes for NO reductase. Prolonged incubation of HCNT1 u...

BACKGROUND AND OBJECTIVES: Nitric oxide (NO) is a potent vasodilator and estrogen-mediated vasodilation that increases NO production. The association of the vascular endothelium, gender and vasodilation induced by estrogen is due to the activation of two estrogen receptors, alpha (ERa) and beta (ERb). The aim of this study was to compare NO production stimulating receptors ERa and ERb with the ...

Exposure to relatively high levels of chlorine (Cl₂) gas can occur in mass-casualty scenarios associated with accidental or intentional release. Recent studies have shown a significant postexposure injury phase to the airways, pulmonary, and systemic vasculatures mediated in part by oxidative stress, inflammation, and dysfunction in endogenous nitric oxide homeostasis pathways. However, there i...

We investigated the enzymatic reduction and oxidation of iron in M.magnetotacticum which synthesizes magnetite at room temperature. NADH-Fe(lI1) reductase with the molecular mass of 36kDa was purified from the bacterium. The enzyme was located in cytoplasm and utilized NADH and NADPH in the presence of FMN as reductant and showed maximum activity at pH 7.0. The Km for NADH and NADPH were about ...

The reversible redox conversion of nitrite and nitric oxide ((•)NO) in a physiological setting is now widely accepted. Nitrite has long been identified as a stable intermediate of (•)NO oxidation but several lines of evidence support the reduction of nitrite to nitric oxide in vivo. In the gut, this notion implies that nitrate from dietary sources fuels the longstanding production of nitrite in...

Urinary nitrite and F(2)-isoprostanes, an index of oxidant stress, were elevated during chlamydial genital infection of mice. Enhancement of urinary nitrite and F(2)-isoprostanes was observed in phagocyte oxidase-deficient mice. Inhibition of inducible nitric oxide synthase reduced isoprostane excretion. We conclude that nitrogen radicals induce F(2)-isoprostane production and excretion during ...

The clinical evaluation of stabilized tetrameric hemoglobin as alternatives to red cells revealed that the materials caused significant increases in blood pressure and related problems and this was attributed to the scavenging of nitric oxide and extravasation. The search for materials with reduced vasoactivity led to the report that conjugates of hemoglobin tetramers and polyethylene glycol (P...

Accumulating evidence suggests that the simple and ubiquitous anion salt, nitrite (NO(2)(-)), is a physiological signaling molecule with potential roles in intravascular endocrine nitric oxide (NO) transport, hypoxic vasodilation, signaling, and cytoprotection after ischemia-reperfusion. Human and animal studies of nitrite treatment and NO gas inhalation provide evidence that nitrite mediates m...

Nitrite has now been proposed to play an important physiological role in signaling, blood flow regulation and hypoxic nitric oxide homeostasis. A recent two-day symposium at the US National Institutes of Health highlighted recent advances in the understanding of nitrite biochemistry, physiology and therapeutics.