Showing papers on "Nitrite published in 1982"
TL;DR: A new automated system for the analysis of nitrate via reduction with a high-pressure cadmium column that automatically eliminates interference from other compounds normally present in urine and other biological fluids is described.
11,238 citations
TL;DR: In this paper, a chemiluminescent analysis technique for the determination of nanomolar quantities of nitrate, nitrate plus nitrite or nitrite alone in seawater is described.
320 citations
190 citations
TL;DR: It is suggested that the C2H2-sensitive step is associated with the ammonia oxygenase, and the oxidation of hydroxylamine to NO2− by Nitrosomonas europaea is affected.
Abstract: Acetylene (C2H2) strongly inhibited (Ki 0.25 μM or 0.66 Pa) the oxidation of ammonia (NH4+) to nitrite (NO2−) by Nitrosomonas europaea but did not affect the oxidation of hydroxylamine (NH2OH) to N...
163 citations
01 Feb 1982
TL;DR: In this paper, it was shown that ammonium-oxidizing bacteria are approximately constant with depth (about 5 × 10 4 cells 1 −1 ), indicating greatly enhanced oxidation rates per cell below the photic zone, indicating that light intensity in the water column may control the depth and formation of the primary nitrite maximum.
Abstract: Autotrophic ammonium oxidation rates are highest (about 4 × 10 −8 mol 1 −1 d −1 or 7.5 × 10 −13 mol cell −1 d −1 ) below the photic zone in the nitrite maximum layer in California coastal waters, with rates approaching zero at the surface. Cell numbers of ammonium-oxidizing bacteria, however, are approximately constant with depth (about 5 × 10 4 cells 1 −1 ), indicating greatly enhanced oxidation rates per cell below the photic zone. Light intensity in the water column may control the depth and formation of the primary nitrite maximum in this coastal regime.
136 citations
TL;DR: Nitrosococcus oceanus, a strongly halophilic bacterium, had a very low tolerance to organic matter compared with other organisms tested, and nitrite formation by both Nitrosovibrio tenuis strains tested was similar.
Abstract: The effect of various organic compounds on the growth of ammonia-oxidizing bacteria was examined.Nitrosococcus oceanus, a strongly halophilic bacterium, had a very low tolerance to organic matter compared with other organisms tested. Organic compounds scarcely affected the growth of theNitrosomonas strains whereas nitrite formation by bothNitrosococcus mobilis strains was inhibited by nearly all of the substances tested. The growth ofNitrosospira strain Nsp1 was enhanced more than 30% by acetate and formate, but not growth was detectable in the presence of pyruvate. On the contrary,Nitrosospira strain Nsp5 was stimulated only by pyruvate. Nitrite formation by the twoNitrosovibrio tenuis strains tested was similar. The growth of both strains was enhanced considerably by formate and glucose; acetate and, to a greater extent, pyruvate inhibited these bacteria. In batch culture, the energy efficiency of autotrophically grown ammonia-oxidizing bacteria varied from strain to strain. The cell yield of mixotrophically grown cultures, per unit of ammonia oxidized, was increased in comparison with autotrophic ones. No heterotrophic growth was detected.
112 citations
TL;DR: The characteristics of inhibitions and the low level of NO generated by nitrite reduction ruled out the suggestion concerning a direct role of NO to explain the inhibitory effect of NO(2) on nitrogenase.
Abstract: Nitrite was able to strongly inhibit C(2)H(2) reduction by nitrogenase from soybean bacteroids, whereas H(2) evolution was unaffected under the same conditions. NO inhibited both C(2)H(2) reduction and H(2) evolution; during C(2)H(2) reduction, sensitivity of nitrogenase to NO was higher than to NO(2), and the K(i) values were, respectively, 0.056 and 0.52 mM. Production of NO resulting from a reduction of NO(2) by dithionite in nitrogenase incubations was observed. However, the characteristics of inhibitions and the low level of NO generated by nitrite reduction ruled out the suggestion concerning a direct role of NO to explain the inhibitory effect of NO(2) on nitrogenase.
111 citations
TL;DR: This increased nitrite production in vitro was associated with methaemoglobinaemia following the oral administration of nitrate to rats fed the diet containing pectin, and animals receiving the basal fibre-free diet were unaffected by nitrate.
Abstract: 1. A semi-synthetic diet, the semi-synthetic diet plus pectin, and a stock diet were fed to rats, and three metabolic functions of the caecal bacteria (reduction of amaranth, p-nitrobenzoic acid and nitrate) were measured in vitro. 2. No consistent differences were noted between diets for the reduction of amaranth and p-nitrobenzoic acid. 3. No consistent differences in nitrate reductase activity were noted for rats maintained on a stock diet or a fibre-free diet. However, the addition of 5% pectin to the latter diet resulted in a several-fold increase in nitrite production. 4. This increased nitrite production in vitro was associated with methaemoglobinaemia following the oral administration of nitrate to rats fed the diet containing pectin. Animals receiving the basal fibre-free diet were unaffected by nitrate.
107 citations
TL;DR: Peroxyacetyl nitrate (PAN) is synthesized by nitration of peracetic acid (1.2 M), extracted by n - heptane, and purified with normal-phase high-performance liquid chromatography.
92 citations
TL;DR: This study provides no evidence that cimetidine treatment may increase the risk of gastric carcinoma by raising N-nitroso-compound concentrations.
89 citations
TL;DR: Methodology has been developed for the rapid determination of nitrate and nitrite in blood and urine via its gas phase chemiluminescence reaction with ozone.
Abstract: Methodology has been developed for the rapid determination of nitrate and nitrite in blood and urine. In solution, these species are selectively reduced to nitric oxide, which is outgassed and determined via its gas phase chemiluminescence reaction with ozone. Differentiation between nitrate and nitrite is obtained by careful selection of reducing agents and conditions.
TL;DR: In this article, a pre-valve in-invalve reduction technique is used to reduce nitrate to nitrite by using the prevalve before the sampling system, which is suitable for the simultaneous determination of nitrate and nitrite at a sampling rate of up to 72 determinations per hour with coefficients of variation better than 1.96% for Nitrate and 0.83% for nitrite.
TL;DR: In this article, the authors studied the properties of dissimilatory nitrate reduction by Propionibacterium acidi-propionici, P. freudenreichii, p. jensenii, P shermanii and P. thoenii and found that the enzymes involved in nitrate and nitrite reduction were either constitutive or derepressed by anacrobiosis.
Abstract: Characteristics of dissimilatory nitrate reduction by Propionibacterium acidi-propionici, P. freudenreichii, P. jensenii, P. shermanii and P. thoenii were studied. All strains reduced nitrate to nitrite and further to N2O. Recovery of added nitrite-N as N2O-N approached 100%, so that no other end product existed in a significant quantity. Specific rates of N2O production were 3 to 6 orders of magnitude lower than specific rates of N2 production by common denitrifiers. Oxygen but not acetylene inhibited N2O production in P. acidi-propionici and P. thoenii. Nitrite reduction rates were generally higher than nitrate reduction rates. The enzymes involved in nitrate and nitrite reduction were either constitutive or derepressed by anacrobiosis. Nitrate stimulated synthesis of nitrate reductase in P. acidi-propionici. Specific growth rates and growth yields were increased by nitrate. At 10 mM, nitrite was toxic to all strains, and at 1 mM its effect ranged from none to total inhibition. No distinction was obvious between incomplete forms of denitrification and dissimilatory nitrate reduction to ammonia. N2O production from nitrite by propionibacteria may represent a detoxication mechanism rather than a part of an energy transformation system.
TL;DR: The results indicate an involvement of copper protein(s) in the last step of nitrite respiration in P. perfectomarinus, and it is found that nitric oxide, a presumed intermediate of nitrites respiration, inhibited nitrous oxide reduction.
Abstract: A synthetic growth medium was purified with the chelator 1,5-diphenylthiocarbazone to study the effects of copper on partial reactions and product formation of nitrite respiration in Pseudomonas perfectomarinus. This organism grew anaerobically in a copper-deficient medium with nitrate or nitrite as the terminal electron acceptor. Copper-deficient cells had high activity for reduction of nitrate, nitrite, and nitric oxide, but little activity for nitrous oxide reduction. High rates of nitrous oxide reduction were observed only in cells grown on a copper-sufficient (1 micro M) medium. Copper-deficient cells converted nitrate or nitrite initially to nitrous oxide instead of dinitrogen, the normal end product of nitrite respiration in this organism. In agreement with this was the finding that anaerobic growth of P. perfectomarinus with nitrous oxide as the terminal electron acceptor required copper. This requirement was not satisfied by substitution of molybdenum, zinc, nickel, cobalt, or manganese for copper. Reconstitution of nitrous oxide reduction in copper-deficient cells was rapid on addition of a small amount of copper, even though protein synthesis was inhibited. The results indicate an involvement of copper protein(s) in the last step of nitrite respiration in P. perfectomarinus. In addition we found that nitric oxide, a presumed intermediate of nitrite respiration, inhibited nitrous oxide reduction.
TL;DR: The characterization of this enzyme was extended to include amino acid composition, extinction coefficients, and kinetic properties not previously reported, and it was found that the competitive kinetics were dominated by nonenzymatic reactions involving an enzyme product, nitric oxide.
TL;DR: It is concluded that sodium nitrite and sodium nitrate did not exert a carcinogenic effect that could be detected under the conditions of this study in which the animals showed a high incidence of spontaneous tumours.
TL;DR: The overall results support the idea that the depression of legume nodule growth by nitrate is directly related to the metabolism of nitrate in nodules.
Abstract: Nodulated soybean plants ( Glycine max [L.] Merr) were grown in sand culture without combined N or with a continuous supply of nitrate in nutrient solution. Moderate nitrate concentration (30 milligrams N per liter) had little effect on nodule weight/plant while high nitrate concentration (100 milligrams N per liter) depressed nodule weight/plant by 70 to 80% with harvests 30 to 60 days after planting and initiation of nitrate treatments. The effect of nitrate supply on ammonium, amino, and ureide nitrogen concentrations in nodules was small and inconsistent. In contrast, nitrate and nitrite concentrations in nodules were directly proportional to nitrate supply and inversely proportional to nodule weight/plant. Correlations between nitrate or nitrite concentration in nodules and nodule weight/plant were highly significant. Cytosol from soybean nodules was found to contain NADH-dependent nitrate reductase activity (typical activity was 0.1 micromole per milligram protein × hour). A Rhizobium japonicum mutant (derived from strain 61A76) lacking nitrate reductase was employed to show that the cytosol enzyme activity is of host origin. Growth of nodules formed by the mutant lacking nitrate reductase was inhibited by nitrate. These nodules did contain nitrite although concentrations of nitrite (about 0.3 microgram N per gram fresh weight) were low relative to nitrite concentrations (about 1.5 microgram N per gram fresh weight) in nodules formed by R. japonicum strain 61A76. The overall results support the idea that the depression of legume nodule growth by nitrate is directly related to the metabolism of nitrate in nodules.
01 Sep 1982
TL;DR: In this paper, the vertical distribution of nitrate and nitrate deficit (nitrate consumed during denitrification) in oxygen minimum zones are modeled using a recycling mechanism incorporating bacterially mediated reaction and diffusion.
Abstract: The vertical distributions of nitrate and nitrate deficit (nitrate consumed during denitrification) in oxygen minimum zones are modeled using a recycling mechanism incorporating bacterially mediated reaction and diffusion. At the core of the oxygen minimum zone bacteria reduce nitrate to nitrite and part of the nitrte to molecular nitrogen (denitrification). The remaining nitrite diffuses out of the layer, is oxidized to nitrate by nitrifying bacteria, and diffuses back into the layer to complete the cycle. The peak nitrite and nitrate deficit concentrations and the amount of recycling depend on two parameters: θ, the ratio of the sum of the nitrate and nitrate reduction rates to the diffusion coefficient, and λ, the ratio of the nitrate reduction rate to the sum of the nitrate and nitrite reduction rates. We estimate from peak concentrations that for oxygen minimum zones in the Arabian Sea, the eastern tropical North Pacific, and the coastal waters of Peru that the nitrogen production rate is between 39 and 60% of the nitrate reduction rate, with the difference in rates equaling the recycling rate between the denitrifying and nitrifying layers. A dependency of θ and λ on organic substrates available to denitrifying bacteria is suggested from independent chemostat studies and the primary productivity overlying the oxygen minimum zones. The peak concentrations of nitrite and nitrate deficit are near the mid-depth of the denitrifying layer, and from this characteristic we estimate the thickness of the denitrifying layers to be between 30 and 70% of the thickness of the oxygen minimum zones.
TL;DR: A total of 46 rhizobial strains were assessed for anaerobic growth in the presence of Nitrate, and, using the criteria of nitrate utilization and nitrous oxide and nitrogen production, for their ability to denitrify.
Abstract: SUMMARY: A total of 46 rhizobial strains were assessed for anaerobic growth in the presence of nitrate, and, using the criteria of nitrate utilization and nitrous oxide and nitrogen production, for their ability to denitrify. Nitrite production was also measured. Half of the strains were denitrifiers: these included all five strains of R. meliloti tested which produced N2 from nitrate and most of the slow-growing rhizobia, but none of the 14 strains of R. trifolii.
TL;DR: The present results indicate a free-radical mechanism for the oxidation in which the asymmetric radical catalyzes the formation of NO2 from NO2- by a peroxidase action and NO2 oxidizes oxyhemoglobin in the autocatalytic phase.
TL;DR: Monitoring of N-nitrosamino acids excreted in the urine and feces appears to provide a valuable index for endogenous N-Nitrosation.
Abstract: A simple and sensitive method for the quantitative estimation of endogenous N-nitrosation in rats has been developed. This approach is based on the findings that N-nitrosamino acids (e.g., nitrosoproline (NPRO), nitrosohydroxyproline (NHPRO) and nitrososarcosine (NSAR)) when administered orally to rats, are excreted unchanged almost quantitatively (88-96% of the dose) in the urine and feces. After sequential administration of a nitrosatable amino acid and sodium nitrite the nitrosamino acid excreted in the urine and feces was analyzed. The amount of NPRO excreted in the urine of rats was proportional to the dose of proline and to the square of the nitrite dose. Co-administration of ascorbic acid and alpha-tocopherol together with the precursors decreased the urinary NPRO whereas thiocyanate increased the yield. After feeding an amino acid precursor and nitrite, the yield of nitrosamino acids formed in vivo and excreted in the urine increased in the order: NPRO less than NSAR less than NHPRO. The same order was seen when the nitrosation rates of the amino acids in vitro were compared. Thus N-nitrosation in vivo in rats occurs via a similar mechanism as observed in vitro. Monitoring of N-nitrosamino acids excreted in the urine and feces thus appears to provide a valuable index for endogenous N-nitrosation.
01 Jan 1982
TL;DR: A set of four isogenic Escherichia coli strains has been constructed in which all possible combinations of NADH- and formate-dependent nitrite reductases are active or inactive, and the observed energy conservation results from the ability of formate dehydrogenase in E. coli to pump protons.
Abstract: ~~~ ____~ A set of four isogenic Escherichia coli strains has been constructed in which all possible combinations of NADH- and formate-dependent nitrite reductases are active or inactive. Each pathway can be inactivated genetically without a corresponding loss in the other activity: the two pathways are therefore biochemically independent. The generation of a membrane potential during nitrite reduction by formate has been demonstrated using an ion-selective electrode specific for a lipophilic cation. The observed energy conservation results, at least in part, from the ability of formate dehydrogenase in E. coli to pump protons.
TL;DR: A set of four isogenic Escherichia coli strains has been constructed in which all possible combinations of NADH- and formate-dependent nitrite reductases are active or inactive.
Abstract: SUMMARY: A set of four isogenic Escherichia coli strains has been constructed in which all possible combinations of NADH- and formate-dependent nitrite reductases are active or inactive. Each pathway can be inactivated genetically without a corresponding loss in the other activity: the two pathways are therefore biochemically independent. The generation of a membrane potential during nitrite reduction by formate has been demonstrated using an ion-selective electrode specific for a lipophilic cation. The observed energy conservation results, at least in part, from the ability of formate dehydrogenase in E. coli to pump protons.
TL;DR: The composite results suggest a mechanism for hemoglobin oxidation that is initiated by the formation of monomeric nitrogen dioxide and propagated by the transfer of superoxide from oxyhemoglobin to nitrogen dioxide, oxidation of the resulting peroxynitrate ion by peroxide, and superoxide oxidation of nitrite ion to nitrogen carbon dioxide and peroxide.
TL;DR: In this paper, the steady state concentration of OH-radicals in different aquatic environments is estimated (∼ 5 · 10 −16 mol/l) depending on the amount of nitrate dissolved in the water.
TL;DR: Catalysis and inhibition of N-nitrosation in rats in vivo appears to occur via mechanisms similar to those in vitro, although the effects in vivo were smaller.
Abstract: Measurements were made of the effects of phenolic compounds, some of which are present in the human diet, on the nitrosation of proline by nitrite to give N-nitrosoproline (NPRO). In vitro, resorcinol, catechin, p-nitrosophenol and phenol were catalysts and chlorogenic acid an inhibitor; guaiacol showed a marginal catalytic effect. Both the catalytic and the inhibiting effects were dependent on pH and on the concentration of phenolic compounds; catalysis by resorcinol and catechin was increased at optimal ratios of [nitrite]: [phenolic compound]. Endogenous nitrosation was examined in vivo by co-administration of nitrite, proline and a phenolic compound to rats and by monitoring the amount of NPRO excreted in the urine. Under similar experimental conditions, the catalytic effects observed in vivo decreased in the same order as those observed in vitro: resorcinol greater than p-nitroso-phenol greater than catechin greater than phenol greater than or equal to guaiacol; chlorogenic acid acted as an inhibitor. Catalysis and inhibition of N-nitrosation in rats in vivo appears to occur via mechanisms similar to those in vitro, although the effects in vivo were smaller. The implications of our findings for the endogenous formation of N-nitroso compounds and for variations in exposure due to different dietary constituents in humans are discussed.