Topic
Nitrite
About: Nitrite is a research topic. Over the lifetime, 15425 publications have been published within this topic receiving 484581 citations.
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TL;DR: In this article, the authors confirmed and extended previous studies by demonstrating that nitrolinoleate, chlolesteryl n-germinate, and nitrohydroxylinoleate induce vasorelaxation in a concentration-dependent manner while releasing nitric oxide that was characterized by chemiluminescence and EPR-based methodologies.
126 citations
TL;DR: Enhanced lipid peroxidation with concomitant decrease in antioxidants is indicative of oxidative stress that provides evidence of the relationship between lipid per oxidation and oral cavity cancer.
Abstract: Objective: The aim of this study was to evaluate the magnitude of oxidative stress and levels of nitric oxide in patients with oral cavity cancer by analyzing the levels of lipid peroxidation products, antioxidants and nitric oxide products. Methods: This prospective study was conducted on 15 patients with biopsy proven squamous cell cancer of the oral cavity with clinical stage III/IV and an equal number of age and sex matched healthy subjects. The levels of lipid peroxidation products, antioxidants and nitric oxide products were determined by colorimetric methods. Results: Lipid peroxidation products like lipid hydroperoxide (LHP) and malondialdehyde (MDA) and nitric oxide products like nitrite (NO2 – ), nitrate (NO3 – ) and total nitrite (TNO2 – ) were significantly elevated, whereas enzymatic and non-enzymatic antioxidants were significantly lowered in oral cavity cancer patients when compared to normal healthy subjects. Conclusions: Enhanced lipid peroxidation with concomitant decrease in antioxidants is indicative of oxidative stress that provides evidence of the relationship between lipid peroxidation and oral cavity cancer. Increased nitric oxide production represents a general mechanism in its pathogenesis.
126 citations
TL;DR: Differences in rate and extent of U(IV) oxidation are due to mineralogical differences between Fe( III) produced by reaction of Fe(II) with nitrite (amorphous) and Fe(III) produced enzymatically (goethite or lepidocrocite).
Abstract: Microbiological reduction of soluble U(VI) to insoluble U(IV) is a means of preventing the migration of that element in groundwater, but the presence of nitrate in U(IV)-containing sediments leads to U(IV) oxidation and remobilizaton. Nitrite or iron(III) oxyhydroxides may oxidize U(IV) under nitrate-reducing conditions, and we determined the rate and extent of U(IV) oxidation by these compounds. Fe(III) oxidized U(IV) at a greater rate than nitrite (130 and 10 μM U(IV)/day, respectively). In aquifer sediments, Fe(III) may be produced during microbial nitrate reduction by oxidation of Fe(II) with nitrite, or by enzymatic Fe(II) oxidation coupled to nitrate reduction. To determine which of these mechanisms was dominant, we isolated a nitrate-dependent acetate- and Fe(II)-oxidizing bacterium from a U(VI)- and nitrate-contaminated aquifer. This organism oxidized U(IV) at a greater rate and to a greater extent under acetate-oxidizing (where nitrite accumulated to 50 mM) than under Fe(II)-oxidizing conditions....
126 citations
TL;DR: A technique is described by which both oxygen and nitrate (or nitrate or chlorate) levels were continuously monitored during bacterial respiration to suggest that the nitrate reductase is orientated on the plasma membrane so that nitrate gains access from the inner (cytosolic) face.
Abstract: SUMMARY: A technique is described by which both oxygen and nitrate (or nitrite or chlorate) levels were continuously monitored during bacterial respiration. Paracoccus (Micrococcus) denitrificans and Escherichia coli oxidizing succinate rapidly ceased to reduce nitrate when oxygen was available, and equally rapidly commenced nitrate reduction when all the oxygen had been consumed. By contrast, membrane vesicles isolated from P. denitrificans reduced oxygen and nitrate simultaneously. The respiratory nitrate reductase in intact cells of P. denitrificans appeared to be inaccessible to chlorate present in the reaction medium, and it is suggested that the nitrate reductase is orientated on the plasma membrane so that nitrate gains access from the inner (cytosolic) face.
126 citations
TL;DR: Ammonium-oxidizing bacteria were examined in two wetland environments, a freshwater marsh and an estuarine bay, during a 2-year period, suggesting that the organism is a trueEstuarine bacterium.
Abstract: Ammonium-oxidizing bacteria were examined in two wetland environments, a freshwater marsh and an estuarine bay, during a 2-year period. Two predominant types were consistently isolated, one from each environment. Both isolates were identified as species ofNitrosomonas. Using a closed culture, high cell density assay, the effects of temperature, pH, salinity, Na(+), K(+), nitrite, nitrate, and ammonium concentrations on ammonium oxidation were determined. Maximum activity was observed for the freshwater isolate at 35°C, pH 8.5, salinities of 0.3 to 0.5% Na(+) and K(+), and ammonium concentrations greater than 0.5 g/l. For the estuarine isolate, maximum activity was observed at 40°C, pH 8.0, salinities of 0.5 to 1.0%, 1.0% Na(+) and K(+), and 0.2 g/l ammonium. The estuarine isolate had a Na(+) requirement which could be partially substituted by the K(+), suggesting that the organism is a true estuarine bacterium. Nitrite inhibited both isolates at concentrations greater than 5 mg/l, whereas nitrate had no significant effect on either isolate.
126 citations