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1

TOXICITY OF AMMONIA, NITRITE AND NITRATE TO FISHES  

EPA Science Inventory

Ammonia and nitrite are highly toxic to fishes, wig ammonia occurring in urface waters more commonly than nitrite. itrate is a related compound but is not ignificantly toxic to fishes. he acute toxicity of ammonia to aquatic organisms s affected by water pH, dissolved oxygen, tem...

2

Reference material for nutrients in seawater: stability of nitrate, nitrite, ammonia and phosphate in autoclaved samples  

Microsoft Academic Search

Reference material is increasingly used as a basis for quality control and quality assurance in general. Results of autoclaving applied to produce reference material for nutrients in seawater are presented and discussed.When preliminary experiments had shown satisfactory behavior of nitrate, nitrite and ammonia when autoclaved together in seawater samples, a 27 month experiment was undertaken with these three nutrients and

Alain Aminot; Roger Kérouel

1995-01-01

3

Ammonia formation by the reduction of nitrite/nitrate by FeS: ammonia formation under acidic conditions.  

PubMed

One issue for the origin of life under a non-reducing atmosphere is the availability of the reduced nitrogen necessary for amino acids, nucleic acids, etc. One possible source of this nitrogen is the formation of ammonia from the reduction of nitrates and nitrites produced by the shock heating of the atmosphere and subsequent chemistry. Ferrous ions will reduce these species to ammonium, but not under acidic conditions. We wish to report results on the reduction of nitrite and nitrate by another source of iron (II), ferrous sulfide, FeS. FeS reduces nitrite to ammonia at lower pHs than the corresponding reduction by aqueous Fe+ 2. The reduction follows a first order decay, in nitrite concentration, with a half-life of about 150 min (room temperature, CO2, pH 6.25). The highest product yield of ammonia measured was 53%. Under CO2, the product yield decreases from pH 5.0 to pH 6.9. The increasing concentration of bicarbonate, at higher pH, interferes with the reaction. Comparing experiments under N2 CO2 shows the interference of bicarbonate. The reaction proceeds well in the presence of such species as chloride, sulfate, and phosphate, though the yield drops significantly with phosphate. FeS also reduces nitrate and, unlike with Fe+ 2, the reduction shows more reproducibility. Again, the product yield decreases with increasing pH, from 7% at pH 4.7 to 0% at pH 6.9. It appears that nitrate is much more sensitive to the presence of added species, perhaps not competing as well for binding sites on the FeS surface. This may be the cause of the lack of reproducibility of nitrate reduction by Fe+ 2 (which also can be sensitive to binding by certain species). PMID:16228644

Summers, David P

2005-08-01

4

Acute toxicity of ammonia, nitrite, and nitrate to the Guadalupe bass, Micropterus treculi  

SciTech Connect

The US Fish and Wildlife Service is presently developing techniques for the intensive culture of Guadalupe bass in order to be prepared to augment natural populations with hatchery fish, should it become necessary. As a part of this development project, this study was conducted to determine the acute toxicity of the common nitrogenous wastes found in aquatic environments (ammonia, nitrite, and nitrate) to the Guadalupe bass. This information will be used to (1) set hatchery water quality criteria for this species, and (2) help determine the suitability of potential stocking waters which may contain high levels of these metabolites.

Tomasso, J.R.; Carmichael, G.J.

1986-06-01

5

Isolation of cDNA clones coding for spinach nitrite reductase: Complete sequence and nitrate induction  

Microsoft Academic Search

The main nitrogen source for most higher plants is soil nitrate. Prior to its incorporation into amino acids, plants reduce nitrate to ammonia in two enzymatic steps. Nitrate is reduced by nitrate reductase to nitrite, which is further reduced to ammonia by nitrite reductase. In this paper, the complete primary sequence of the precursor protein for spinach nitrite reductase has

Eduard Back; William Burkhart; Mary Moyer; Laura Privalle; Steven Rothstein

1988-01-01

6

Nitrate reduction, nitrous oxide formation, and anaerobic ammonia oxidation to nitrite in the gut of soil-feeding termites (Cubitermes and Ophiotermes spp.).  

PubMed

Soil-feeding termites play important roles in the dynamics of carbon and nitrogen in tropical soils. Through the mineralization of nitrogenous humus components, their intestinal tracts accumulate enormous amounts of ammonia, and nitrate and nitrite concentrations are several orders of magnitude above those in the ingested soil. Here, we studied the metabolism of nitrate in the different gut compartments of two Cubitermes and one Ophiotermes species using (15)N isotope tracer analysis. Living termites emitted N(2) at rates ranging from 3.8 to 6.8 nmol h(-1) (g fresh wt.)(-1). However, in homogenates of individual gut sections, denitrification was restricted to the posterior hindgut, whereas nitrate ammonification occurred in all gut compartments and was the prevailing process in the anterior gut. Potential rates of nitrate ammonification for the entire intestinal tract were tenfold higher than those of denitrification, implying that ammonification is the major sink for ingested nitrate in the intestinal tract of soil-feeding termites. Because nitrate is efficiently reduced already in the anterior gut, reductive processes in the posterior gut compartments must be fuelled by an endogenous source of oxidized nitrogen species. Quite unexpectedly, we observed an anaerobic oxidation of (15)N-labelled ammonia to nitrite, especially in the P4 section, which is presumably driven by ferric iron; nitrification and anammox activities were not detected. Two of the termite species also emitted substantial amounts of N(2) O, ranging from 0.4 to 3.9 nmol h(-1) (g fresh wt.)(-1), providing direct evidence that soil-feeding termites are a hitherto unrecognized source of this greenhouse gas in tropical soils. PMID:22118414

Ngugi, David Kamanda; Brune, Andreas

2011-11-28

7

Acute and chronic toxicity of ammonia, nitrite, and nitrate to the endangered Topeka shiner (Notropis topeka) and fathead minnows (Pimephales promelas).  

PubMed

Toxicity tests with ammonia, nitrite, and nitrate were conducted on the endangered Topeka shiner (Notropis topeka) to determine if current U.S. Environmental Protection Agency (U.S. EPA) water quality criteria are protective of this species. Results from acute lethal and chronic growth tests are reported for both Topeka shiners and fathead minnows (Pimephales promelas). Embryo-larval tests were conducted with only fathead minnows because Topeka shiner embryos were not available. Predicted outcomes for Topeka shiner embryo-larval toxicity endpoints were calculated by comparing relationships between growth tests and embryo-larval tests for fathead minnows and extrapolating those relationships to Topeka shiners. Results show that the U.S. EPA's criterion for total ammonia-nitrogen (TAN), 1.24 mg/L when early life stages are present, would be protective, given that our most sensitive result was a predicted maximum acceptable toxicant concentration (MATC) for Topeka shiners at 5.63 mg/L TAN, calculated from the fathead minnow chronic embryo-larval test. The U.S. EPA's criterion for nitrite (5 mg/L) would not be protective, given that our most sensitive result was a predicted MATC for Topeka shiners of 3.97 mg/L NO2-N, calculated from the fathead minnow chronic embryo-larval test. However, nitrite is generally transient, and unpublished field data show levels far lower than the criterion. Finally, the U.S. EPA's recommendation of a maximum of 90 mg/L NO3-N for the protection of warmwater fishes would protect Topeka shiners but not fathead minnows. For Topeka shiners, the MATC from the 30-d juvenile growth test was 360 mg/L NO3-N, but for fathead minnows, the MATC was 84 mg/L. More field sampling may be needed to determine if levels comply with criteria, especially in Topeka shiner critical habitat. PMID:19459722

Adelman, Ira R; Kusilek, Luke I; Koehle, Jessica; Hess, Jonathan

2009-10-01

8

Nitrite and Nitrate in Cancer  

Microsoft Academic Search

\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Studies in animal models established the feasibility of sodium nitrite contributing to gastric carcinogenesis primarily via\\u000a conversion to nitrosamines.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Most animal studies did not corroborate this assumption.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Exposure of humans to nitrates is primarily from vegetables.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Since a fraction of nitrate is reduced to nitrite by oral bacteria, the largest source of nitrite exposure is also

David M. Klurfeld

9

9 CFR 319.2 - Products and nitrates and nitrites.  

Code of Federal Regulations, 2013 CFR

...false Products and nitrates and nitrites. 319...and Animal Products FOOD SAFETY AND INSPECTION...319.2 Products and nitrates and nitrites. Any...there is a standard in this part and to which nitrate or nitrite is...

2013-01-01

10

Influence of dietary nitrate on nitrite level of human saliva  

Microsoft Academic Search

The amount of nitrite in saliva depends directly on the amount of nitrate and nitrite ingested. Ingested nitrate and nitrite are absorbed by the upper gastrointestinal tract, concentrated from the plasma and excreted into the saliva by salivary glands. The presence of nitrate-reducing bacteria in the mouth caused nitrite to be formed, resulting in higher nitrite concentration. In recent years

M. Ipek Cingi; Cemal Cingi; Emre Cingi

1992-01-01

11

Nitrates, Nitrites, and Health. Bulletin 750.  

ERIC Educational Resources Information Center

|This review is intended to assess available literature in order to define the range of nitrate/nitrite effects on animals. Though the literature deals primarily with livestock and experimental animals, much of the contemporary research is concerned with human nitrite intoxication. Thus, the effects on man are discussed where appropriate. Some of…

Deeb, Barbara S.; Sloan, Kenneth W.

12

Nitrate and Nitrite in Normal Gastric Juice  

Microsoft Academic Search

The nitrate and nitrite levels of 75 gastric juice samples from young and healthy fasting volunteers were examined. For both parameters a dependence on the specific pH value of the secretion was detected. The rise of the nitrite level from normal 0.1 ppm in the acid to 1.4 ppm in the neutral range can be explained by the activity of

R. L. Mueller; H.-J. Hagel; H. Wild; H. Ruppin; W. Domschke

1986-01-01

13

Dietary exposure models for nitrates and nitrites  

Microsoft Academic Search

Models to assess dietary exposure of population groups to nitrates and nitrites should be based on the major sources of these substances in foods. Most models require the use of food consumption information and will, therefore, be flawed by the problems that exist with current dietary intake assessment methods. The Total Diet Study model would probably not provide representative coverage

Jean A. T. Pennington

1998-01-01

14

Oxidation of carbon by nitrites and nitrates  

SciTech Connect

This article examines the burning of stoichiometric mixtures of alkaline, alkaline-earth, and ammonium nitrites with carbon. The results are compared with data for analogous mixtures containing nitrates. The effects of the specimen density on the mass combustion rate is investigated in order to establish the combustion mechanism. Mixtures in which the charcoal was replaced by wood flour were examined in order to establish the catalytic role of the charcoal in the combustion. The role of catalysts is considered when they are introduced into the mixture in the form of nitrites, which act simultaneously as oxidants, and when they are added to stoichiometric mixtures. The relation between thermochemical characteristics, combustion rate, and the catalyst mechanism is also considered. The derivative recording of the decomposition of nitrites and mixtures based on them were performed in order to establish a correlation between thermal decomposition and combustion. It is determined that the addition of charcoal and sulfur accelerated thermal decomposition and combustion.

Glazkova, A.P.; Kazarova,; Savel'ev, A.V.

1983-11-01

15

History of Nitrite and Nitrate in Food  

Microsoft Academic Search

\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Saltpeter (potassium nitrate), a natural contaminant of salt, contributed historically to the pinkish-red color in salted\\u000a meats\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Nitric oxide, derived from nitrate\\/nitrite reduction, when combined with myoglobin produces as the color pigment in cured\\u000a meat products\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Nitrite prevents sporulation of Clostridium boutlinum in cured meats\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a In 1925, the United States Department of Agriculture (USDA) approved nitrite’s

Jimmy T. Keeton

16

A Novel Nitrate/Nitrite Permease in the Marine Cyanobacterium Synechococcus sp. Strain PCC 7002  

PubMed Central

The nrtP and narB genes, encoding nitrate/nitrite permease and nitrate reductase, respectively, were isolated from the marine cyanobacterium Synechococcus sp. strain PCC 7002 and characterized. NrtP is a member of the major facilitator superfamily and is unrelated to the ATP-binding cassette-type nitrate transporters that previously have been described for freshwater strains of cyanobacteria. However, NrtP is similar to the NRT2-type nitrate transporters found in diverse organisms. An nrtP mutant strain consumes nitrate at a 4.5-fold-lower rate than the wild type, and this mutant grew exponentially on a medium containing 12 mM nitrate at a rate approximately 2-fold lower than that of the wild type. The nrtP mutant cells could not consume nitrite as rapidly as the wild type at pH 10, suggesting that NrtP also functions in nitrite uptake. A narB mutant was unable to grow on a medium containing nitrate as a nitrogen source, although this mutant could grow on media containing urea or nitrite with rates similar to those of the wild type. Exogenously added nitrite enhanced the in vivo activity of nitrite reductase in the narB mutant; this suggests that nitrite acts as a positive effector of nitrite reductase. Transcripts of the nrtP and narB genes were detected in cells grown on nitrate but were not detected in cells grown on urea or ammonia. Transcription of the nrtP and narB genes is probably controlled by the NtcA transcription factor for global nitrogen control. The discovery of a nitrate/nitrite permease in Synechococcus sp. strain PCC 7002 suggests that significant differences in nutrient transporters may occur in marine and freshwater cyanobacteria.

Sakamoto, Toshio; Inoue-Sakamoto, Kaori; Bryant, Donald A.

1999-01-01

17

Inactivation of Yersinia enterocolitica by nitrite and nitrate in food  

Microsoft Academic Search

The antimicrobial effects of sodium nitrite and sodium and potassium nitrate against Yersinia enterocolitica were investigated in solution and in treated pork meat. Potassium nitrate and sodium nitrate showed only feeble antimicrobial activity in cultures; no antimicrobial activity was detected with sodium nitrite. Conversely, all three salts displayed apparent antimicrobial activity in pork meat, possibly due to selective effects on

M. De Giusti; E. De Vito

1992-01-01

18

Silver Electrode Potentials in Alkali Nitrate and Nitrite Melts.  

National Technical Information Service (NTIS)

The correlation of the nitrate and nitrite systems through the use of a silver electrode is described. Consideration is also given to the use of a nitrate-nitrite solvent mixture and to the effect of changing the cation in the nitrate.

L. G. Boxall K. E. Johnson

1968-01-01

19

Dietary nitrate and nitrite modulate blood and organ nitrite and the cellular ischemic stress response  

PubMed Central

Dietary nitrate, found in abundance in green vegetables, can be converted to the cytoprotective molecule nitrite by oral bacteria, suggesting that nitrate and nitrite may represent active cardioprotective constituents of the Mediterranean diet. We therefore tested the hypothesis that dietary nitrate and nitrite levels modulate tissue damage and ischemic gene expression in a mouse liver ischemia-reperfusion model. We found that stomach content, plasma, heart and liver nitrite levels were significantly reduced after dietary nitrate and nitrite depletion, and could be restored to normal levels with nitrite supplementation in water. Remarkably, we confirmed that basal nitrite levels significantly reduced liver injury after ischemia-reperfusion. Consistent with an effect of nitrite on the post-translational modification of complex I of the mitochondrial electron transport chain, the severity of liver infarction was inversely proportional to complex I activity after nitrite repletion in the diet. The transcriptional response of dietary nitrite after ischemia was more robust than after normoxia, suggesting a hypoxic potentiation of nitrite-dependent transcriptional signaling. Our studies indicate that normal dietary nitrate and nitrite levels modulate ischemic stress responses and hypoxic gene expression programs, supporting the hypothesis that dietary nitrate and nitrite are cytoprotective components of the diet.

Raat, Nicolaas J.H.; Noguchi, Audrey C.; Liu, Virginia B.; Raghavachari, Nalini; Liu, Delong; Xu, Xiuli; Shiva, Sruti; Munson, Peter J.; Gladwin, Mark T.

2009-01-01

20

Simultaneous ultraviolet spectrophotometric determination of nitrate and nitrite in water  

SciTech Connect

A rapid and accurate method for the direct simultaneous determination of nitrate and nitrite is proposed. The method is applied to the determination of nitrate and nitrite in rainwater and wastewater without preliminary separation. The determinations are performed by a CPA matrix method with ultraviolet spectrophotometric detection. The results obtained are in agreement with those obtained by conventional methods for the determination of nitrate and nitrite.

Dong Huiru; Zhang Qing (Liaoyang Petrochemical College (China)); Jiang Meiyu (Liao Hua Oil Refinery, Liaoyang (China))

1991-02-01

21

Method for producing nitrous oxide by reacting ammonia with a molten nitrate salt of an alkaline earth metal  

SciTech Connect

This patent describes a continuous method for producing nitrous oxide by the steps of: (a) reacting ammonia with at least one molten nitrate salt of an alkaline earth metal at reaction conditions to produce the nitrous oxide, thereby converting at least a portion of the molten nitrate salt to molten nitrite salt, (b) reconverting the molten nitrite salt to molten nitrate salt by reacting the molten nitrite salt with an oxidizing agent, and (c) repeating steps (a) and (b) in a continuous manner.

Pennington, B.T.

1988-01-19

22

Enzymology of the oxidation of ammonia to nitrite by bacteria  

Microsoft Academic Search

The enzymes which catalyze the oxidation of ammonia to nitrite by autotrophic bacteria are reviewed. A comparison is made with enzymes which catalyze the same reactions in methylotrophs and organotrophic heterotrophic bacteria.

Alan B. Hooper; Todd Vannelli; David J. Bergmann; David M. Arciero

1997-01-01

23

ACUTE TOXICITY OF AMMONIA AND NITRITE TO CUTTHROAT TROUT FRY  

EPA Science Inventory

The toxicity of ammonia and of nitrite was tested on cutthroat trout (Salmo clarki) fry (1-3 g) for periods up to a month in eight laboratory flow-through bioassays. Median lethal concentration (LC50) values for ammonia (mg/liter un-ionized NH3) were 0.5-0.8 for 96 hours, and 0.3...

24

Influence of dietary nitrate on nitrite level of human saliva  

SciTech Connect

The amount of nitrite in saliva depends directly on the amount of nitrate and nitrite ingested. Ingested nitrate and nitrite are absorbed by the upper gastrointestinal tract, concentrated from the plasma and excreted into the saliva by salivary glands. The presence of nitrate-reducing bacteria in the mouth caused nitrite to be formed, resulting in higher nitrite concentration. In recent years it has been shown that the measurement of some drugs and agents in mixed saliva might be a reliable guide to blood or body levels of those agents. In this present study the level of nitrite in mixed and parotid saliva in Eskisehir (Western part of middle Anatolia) and the correction between sex, smoking and age was determined. The effects of drinking water and meat products on nitrite levels were determined.

Cingi, M.I.; Cingi, C.; Cingi, E. (Anadolu Univ., Eskisehir (Turkey))

1992-01-01

25

Crystal structure of a nitrate/nitrite exchanger.  

PubMed

Mineral nitrogen in nature is often found in the form of nitrate (NO3(-)). Numerous microorganisms evolved to assimilate nitrate and use it as a major source of mineral nitrogen uptake. Nitrate, which is central in nitrogen metabolism, is first reduced to nitrite (NO2(-)) through a two-electron reduction reaction. The accumulation of cellular nitrite can be harmful because nitrite can be reduced to the cytotoxic nitric oxide. Instead, nitrite is rapidly removed from the cell by channels and transporters, or reduced to ammonium or dinitrogen through the action of assimilatory enzymes. Despite decades of effort no structure is currently available for any nitrate transport protein and the mechanism by which nitrate is transported remains largely unknown. Here we report the structure of a bacterial nitrate/nitrite transport protein, NarK, from Escherichia coli, with and without substrate. The structures reveal a positively charged substrate-translocation pathway lacking protonatable residues, suggesting that NarK functions as a nitrate/nitrite exchanger and that protons are unlikely to be co-transported. Conserved arginine residues comprise the substrate-binding pocket, which is formed by association of helices from the two halves of NarK. Key residues that are important for substrate recognition and transport are identified and related to extensive mutagenesis and functional studies. We propose that NarK exchanges nitrate for nitrite by a rocker switch mechanism facilitated by inter-domain hydrogen bond networks. PMID:23665960

Zheng, Hongjin; Wisedchaisri, Goragot; Gonen, Tamir

2013-05-12

26

Reduction of nitrite and nitrate to ammonium on pyrite.  

PubMed

An important constraint on the formation of the building blocks of life in the Hadean is the availability of small, activated compounds such as ammonia (NH(3)) relative to its inert dinitrogen source. Iron-sulfur particles and/or mineral surfaces have been implicated to provide the catalytic active sites for the reduction of dinitrogen. Here we provide a combined kinetic, spectroscopic, and computational modeling study for an alternative source of ammonia from water soluble nitrogen oxide ions. The adsorption of aqueous nitrite (NO(2)(-)) and nitrate (NO(3)(-)) on pyrite (FeS(2)) and subsequent reduction chemistry to ammonia was investigated at 22°C, 70°C, and 120°C. Batch geochemical and in situ Attenuated Total Reflection - Fourier Transform Infrared (ATR-FTIR) spectroscopy experiments were used to determine the reduction kinetics to NH(3) and to elucidate the identity of the surface complexes, respectively, during the reaction chemistry of NO(2)(-) and NO(3)(-). Density functional theory (DFT) calculations aided the interpretation of the vibrational data for a representative set of surface species. Under the experimental conditions used in this study, we detected the adsorption of nitric oxide (NO) intermediate on the pyrite surface. NH(3) production from NO(2)(-) occurred at 70 and 120°C and from NO(3)(-) occurred only at 120°C. PMID:22562476

Singireddy, Soujanya; Gordon, Alexander D; Smirnov, Alexander; Vance, Michael A; Schoonen, Martin A A; Szilagyi, Robert K; Strongin, Daniel R

2012-05-06

27

Nitrate and nitrite in foods and the diet  

Microsoft Academic Search

Concentrations of nitrate and nitrite have been determined in a range of foods and the dietary intake estimated from the MAFF Total Diet Study. The estimated dietary intake of nitrate ion for the UK population was 54 mg\\/day and the estimated dietary intake of nitrite ion was in the range 2.4–4.2 mg\\/day in 1985. The main source of nitrate in

M. N. Meah; N. Harrison; A. Davies

1994-01-01

28

Sugar-driven prebiotic synthesis of ammonia from nitrite.  

PubMed

Reaction of 3-5 carbon sugars, glycolaldehyde, and alpha-ketoaldehydes with nitrite under mild anaerobic aqueous conditions yielded ammonia, an essential substrate for the synthesis of nitrogen-containing molecules during abiogenesis. Under the same conditions, ammonia synthesis was not driven by formaldehyde, glyoxylate, 2-deoxyribose, and glucose, a result indicating that the reduction process requires an organic reductant containing either an accessible alpha-hydroxycarbonyl group or an alpha-dicarbonyl group. Small amounts of aqueous Fe(+3) catalyzed the sugar-driven synthesis of ammonia. The glyceraldehyde concentration dependence of ammonia synthesis, and control studies of ammonia's reaction with glyceraldehyde, indicated that ammonia formation is accompanied by incorporation of part of the synthesized ammonia into sugar-derived organic products. The ability of sugars to drive the synthesis of ammonia is considered important to abiogenesis because it provides a way to generate photochemically unstable ammonia at sites of sugar-based origin-of-life processes from nitrite, a plausible prebiotic nitrogen species. PMID:20213158

Weber, Arthur L

2010-03-07

29

Dissimilatory Nitrite Reductase Genes from Autotrophic Ammonia-Oxidizing Bacteria  

Microsoft Academic Search

The presence of a copper-containing dissimilatory nitrite reductase gene (nirK) was discovered in several isolates of b-subdivision ammonia-oxidizing bacteria using PCR and DNA sequencing. PCR primers Cunir3 and Cunir4 were designed based on published nirK sequences from denitrifying bacteria and used to amplify a 540-bp fragment of the nirK gene from Nitrosomonas marina and five additional isolates of ammonia-oxidizing bacteria.

KAREN L. CASCIOTTI; BESS B. WARD

2001-01-01

30

Acute toxicity of nitrate and nitrite to sensitive freshwater insects, mollusks, and a crustacean.  

PubMed

Both point- and nonpoint-sources of pollution have contributed to increased inorganic nitrogen concentrations in freshwater ecosystems. Although numerous studies have investigated the toxic effects of ammonia on freshwater species, relatively little work has been performed to characterize the acute toxicity of the other two common inorganic nitrogen species: nitrate and nitrite. In particular, to our knowledge, no published data exist on the toxicity of nitrate and nitrite to North American freshwater bivalves (Mollusca) or stoneflies (Insecta, Plecoptera). We conducted acute (96-h) nitrate and nitrite toxicity tests with two stonefly species (Allocapnia vivipara and Amphinemura delosa), an amphipod (Hyalella azteca), two freshwater unionid mussels (Lampsilis siliquoidea and Megalonaias nervosa), a fingernail clam (Sphaerium simile), and a pond snail (Lymnaea stagnalis). Overall, we did not observe a particularly wide degree of variation in sensitivity to nitrate, with median lethal concentrations ranging from 357 to 937 mg NO(3)-N/l; furthermore, no particular taxonomic group appeared to be more sensitive to nitrate than any other. In our nitrite tests, the two stoneflies tested were by far the most sensitive, and the three mollusks tested were the least sensitive. In contrast to what was observed in the nitrate tests, variation among species in sensitivity to nitrite spanned two orders of magnitude. Examination of the updated nitrite database, including previously published data, clearly showed that insects tended to be more sensitive than crustaceans, which were in turn more sensitive than mollusks. Although the toxic mechanism of nitrite is generally thought to be the conversion of oxygen-carrying pigments into forms that cannot carry oxygen, our observed trend in sensitivity of broad taxonomic groups, along with information on respiratory pigments in those groups, suggests that some other yet unknown mechanism may be even more important. PMID:21877224

Soucek, D J; Dickinson, A

2011-08-30

31

The tricky task of nitrate/nitrite antiport.  

PubMed

Subtle differences: Two recent crystal structures have provided the first insight into nitrate/nitrite exchangers (example shown with bound nitrite), which are crucial to bacterial metabolism. A direct comparison of the structures reveals how the proteins can distinguish between their highly similar substrates and translate this into a conformational change to translocate ions across the membrane. PMID:23934766

Andrade, Susana L A; Einsle, Oliver

2013-08-09

32

Spectrophotometric determination of nitrite and nitrate using phosphomolybdenum blue complex  

Microsoft Academic Search

A method for spectrophotometric determination of nitrite and nitrate is described. This method is based on the reduction of phosphomolybdic acid to phosphomolybdenum blue complex by sodium sulfide. The obtained phosphomolybdenum blue complex is oxidized by the addition of nitrite and this causes a reduction in intensity of the blue color. The absolute decrease in the absorbance of the blue

Nidal A. Zatar; Maher A. Abu-Eid; Abdullah F. Eid

1999-01-01

33

Lithotrophic growth of Sulfurospirillum deleyianum with sulfide as electron donor coupled to respiratory reduction of nitrate to ammonia  

Microsoft Academic Search

Sulfurospirillum deleyianum grew in batch culture under anoxic conditions with sulfide (up to 5 mM) as electron donor, nitrate as electron acceptor,\\u000a and acetate as carbon source. Nitrate was reduced to ammonia via nitrite, a quantitatively liberated intermediate. Four moles\\u000a of sulfide were oxidized to elemental sulfur per mole nitrate converted to ammonia. The molar growth yield per mole sulfide

Effi Eisenmann; Joachim Beuerle; Klaus Sulger; Peter M. H. Kroneck; Wolfram Schumacher

1995-01-01

34

Evaluation of nitrate and nitrite destruction/separation technologies  

SciTech Connect

This report describes and evaluates four types of nitrate and nitrite destruction and separation technologies that could be used to treat the aqueous, alkaline, nitrate-bearing mixed waste that is generated by the In-Tank Precipitation (ITP) process at the Savannah River Site (SRS). The technologies considered in this report include thermal, hydrothermal, chemical, and electrochemical technologies.

Hobbs, D.T.

1997-08-29

35

Technological and economic update on the nitrate to ammonia and ceramic process  

SciTech Connect

The Nitrate to Ammonia and Ceramic (NAC) process, which was developed several years ago at the Oak Ridge National Laboratory (ORNL), still remains relatively unknown. This is despite its simplicity in converting nitrate or nitrite to ammonia gas at high efficiency while forming a very useful hydrated alumina-based solid that binds most metals and nonmetals. Two recent Department of Energy (DOE)-contracted total life-cycle cost analyses, related to treating nitrate-based wastes at Hanford, Savannah River, and Oak Ridge, have shown that the NAC technology is only one-third to one-fourth the cost of vitrification, electroreduction, steam reforming, and plasma arc.

Mattus, A.J.

1998-05-01

36

Aerobic nitrate respiration in a nitrite-oxidising bioreactor  

Microsoft Academic Search

The ability of heterotrophic bacteria in a nitrite-oxidising bioreactor to respire with nitrate as an electron acceptor was examined. Approximately 70% of 1000 heterotrophic isolates were able to express a nitrate reductase. A detailed survey of 15 isolates showed that five expressed the azide-insensitive nitrate reductase encoded by the napA gene. A two-round PCR amplification of the napA gene using

Christopher McDevitt; Paul Burrell; Linda L. Blackall; Alastair G. McEwan

2000-01-01

37

Electrochemical reduction of nitrate and nitrite in simulated liquid nuclear wastes  

Microsoft Academic Search

The electrochemical reduction of nitrate and nitrite in simulated low-level nuclear wastes containing 1.8M NaNO3+0.55M NaNO2+1.16M NaOH was studied under galvanostatic polarization on tin and bismuth cathodes. The rate of the reduction of nitrate was about the same on both metals. The selectivity (%S) to ammonia was similar on the two metals (12% at 450mA\\/cm2) and that to nitrogen 82%

I. Katsounaros; M. Dortsiou; G. Kyriacou

2009-01-01

38

The Action of Light on Nitrate and Nitrite Assimilation by the Marine Chlorophyte, Dunaliella tertiolecta (Butcher)  

Microsoft Academic Search

SUMMARY Light caused up to a 20-fold increase in the rate of nitrate and nitrite assimilation by the marine chlorophyte Dunahella tertiolecta. While higher rates of oxygen evolution were observed during both nitrate and nitrite assimilation, the extra oxygen released was not related to the amounts of nitrate or nitrite assimilated. Carbon dioxide was required for light to increase nitrate

B. R. GRANT; N. S. W. Australia

1967-01-01

39

Food sources of nitrates and nitrites: the physiologic context for potential health benefits1-3  

Microsoft Academic Search

The presence of nitrates and nitrites in food is associated with an increased risk of gastrointestinal cancer and, in infants, methemoglo- binemia. Despite the physiologic roles for nitrate and nitrite in vas- cular and immune function, consideration of food sources of nitrates and nitrites as healthful dietary components has received little atten- tion. Approximately 80% of dietary nitrates are derived

Norman G Hord; Yaoping Tang; Nathan S Bryan

2009-01-01

40

Nitrate, Nitrite, and nitroso compounds in foods  

Microsoft Academic Search

The concern that human foods might contain nitroso compounds stems from the discovery in the early 1960s that domestic animals fed fish meal preserved with high levels of sodium nitrite were dying of liver failure. It has been known for many years that nitrite can combine with amines to form N-nitrosamines. N-nitrosodimethylamine was determined to be the cause of the

J. H. Hotchkiss; R. G. Cassens

1987-01-01

41

Prebiotic ammonia from reduction of nitrite by iron (II) on the early Earth.  

PubMed

Theories for the origin of life require the availability of reduced (or 'fixed') nitrogen-containing compounds, in particular ammonia. In reducing atmospheres, such compounds are readily formed by electrical discharges, but geochemical evidence suggests that the early Earth had a non-reducing atmosphere, in which discharges would have instead produced NO. This would have been converted into nitric and nitrous acids and delivered to the early oceans as acid rain. It is known, however, that Fe(II) was present in the early oceans at much higher concentrations than are found today, and thus the oxidation of Fe(II) to Fe(III) provides a possible means for reducing nitrites and nitrates to ammonia. Here we explore this possibility in a series of experiments which mimic a broad range of prebiotic seawater conditions (the actual conditions on the early Earth remain poorly constrained). We find that the reduction by Fe(II) of nitrites and nitrates to ammonia could have been a significant source of reduced nitrogen on the early Earth, provided that the ocean pH exceeded 7.3 and is favoured for temperatures greater than about 25 degrees C. PMID:11540245

Summers, D P; Chang, S

1993-10-14

42

Relation between nitrate and nitrite food habits with lung cancer.  

PubMed

Nitrites, a probable human carcinogen, generate reactive nitrogen species that may cause damage to the lung. We evaluated the association between nutritional habits related to nitrite and nitrate intake and risk of lung cancer in Mazandaran, Northern Province of Iran. In this case-control study the two groups were matched for gender and age (+/- 5 years). A semi -quantitative food frequency questionnaire (FFQ) was used to collect dietary data about nutritional habits related to nitrate, nitrite, vitamins E and C intake, from 40 lung cancer cases and 40 control subjects admitted at Mazanaran hospitals. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of lung cancer using logistic regression. Mean score of nutritional habits in case group was significantly lower than that in control group (P less than or equal 0.001). We observed a positive association between animal sources of nitrate and nitrite intake (OR = 2.7, 95% CI: 0.13-0.96) and risk of lung cancer. Decreased risk of lung cancer was also observed with fruit intake (OR = 0.26, 95% CI: 1.3-11). Our results indicate a probable association between nutritional habits related to animal sources of nitrate and nitrite intake and the risk of lung cancer that requires to be confirmed by other studies. PMID:23350350

Karimzadeh, Laleh; Koohdani, Fariba; Siassi, Fereydoon; Mahmoudi, Mahmoud; Moslemi, Daryoush; Safari, Farid

2012-01-01

43

Plasma nitrate and nitrite are increased by a high nitrate supplement, but not by high nitrate foods in older adults  

PubMed Central

Little is known about the effect of dietary nitrate on the nitrate/nitrite/NO (nitric oxide) cycle in older adults. We examined the effect of a 3-day control diet vs. high nitrate diet, with and without a high nitrate supplement (beetroot juice), on plasma nitrate and nitrite kinetics, and blood pressure using a randomized four period cross-over controlled design. We hypothesized that the high nitrate diet would show higher levels of plasma nitrate/nitrite and blood pressure compared to the control diet, which would be potentiated by the supplement. Participants were eight normotensive older men and women (5 female, 3 male, 72.5±4.7 yrs) with no overt disease or medications that affect NO metabolism. Plasma nitrate and nitrite levels and blood pressure were measured prior to and hourly for 3 hours after each meal. The mean daily changes in plasma nitrate and nitrite were significantly different from baseline for both control diet+supplement (p<0.001 and =0.017 for nitrate and nitrite, respectively) and high nitrate diet+supplement (p=0.001 and 0.002), but not for control diet (p=0.713 and 0.741) or high nitrate diet (p=0.852 and 0.500). Blood pressure decreased from the morning baseline measure to the three 2 hr post-meal follow-up time-points for all treatments, but there was no main effect for treatment. In healthy older adults, a high nitrate supplement consumed at breakfast elevated plasma nitrate and nitrite levels throughout the day. This observation may have practical utility for the timing of intake of a nitrate supplement with physical activity for older adults with vascular dysfunction.

Miller, Gary D.; Marsh, Anthony P.; Dove, Robin W.; Beavers, Daniel; Presley, Tennille; Helms, Christine; Bechtold, Erika; King, S. Bruce; Kim-Shapiro, Daniel

2012-01-01

44

Acute toxicity of ammonia and nitrite to shortnose sturgeon fingerlings  

USGS Publications Warehouse

The 96-h median-lethal concentration (96-h LC50) of total ammonia nitrogen (ammonia-N) to fingerling shortnose sturgeon Acipenser brevirostrum was 149.8 ?? 55.20 mg/L (mean ?? SD, 17.9 ?? 0.62??C, pH = 6.8-7.3). Calculated 96-h LC50 for un-ionized ammonia-N was 0.58 ?? 0.213 mg/L. The 96-h LC50 of nitrite nitrogen to shortnose sturgeon fingerlings was 11.3 ?? 8.17 mg/L (17.9 ?? 0.31??C, <1.0 mg chloride/L, <1.0 mg magnesium/L, 1.8 mg calcium/L, 7.7 mg sodium/L).

Fontenot, Q. C.; Isely, J. J.; Tomasso, J. R.

1998-01-01

45

21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.  

Code of Federal Regulations, 2010 CFR

...Specific Administrative Rulings and Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are food additives when combined in curing premixes with spices and/or other flavoring or...

2010-01-01

46

21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.  

Code of Federal Regulations, 2010 CFR

...Specific Administrative Rulings and Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are food additives when combined in curing premixes with spices and/or other flavoring or...

2009-04-01

47

The reproducibility of the conversion of nitrate to nitrite in human saliva after a nitrate load.  

PubMed

We investigated the reproducibility of the inter- and intra-individual variations in the conversion of nitrate to nitrite in saliva. Saliva samples were collected from 20 volunteers just before and at regular intervals after a nitrate load on four non-consecutive days within a period of 2 months. On three occasions beetroot juice was the nitrate source and on one occasion a nitrate solution was given. Despite large day-to-day variations it was possible to discriminate between subjects with a consistently high or low nitrate conversion after a nitrate load. Neither saliva sampling before a nitrate load nor single saliva samples are sufficient to obtain clear information about individual capacities for nitrate-nitrite conversion. PMID:3366416

Bos, P M; Van den Brandt, P A; Wedel, M; Ockhuizen, T

1988-02-01

48

Impacts of nitrate and nitrite on physiology of Shewanella oneidensis.  

PubMed

Shewanella oneidensis exhibits a remarkable versatility in anaerobic respiration, which largely relies on its diverse respiratory pathways. Some of these are expressed in response to the existence of their corresponding electron acceptors (EAs) under aerobic conditions. However, little is known about respiration and the impact of non-oxygen EAs on the physiology of the microorganism when oxygen is present. Here we undertook a study to elucidate the basis for nitrate and nitrite inhibition of growth under aerobic conditions. We discovered that nitrate in the form of NaNO3 exerts its inhibitory effects as a precursor to nitrite at low concentrations and as an osmotic-stress provider (Na(+)) at high concentrations. In contrast, nitrite is extremely toxic, with 25 mM abolishing growth completely. We subsequently found that oxygen represses utilization of all EAs but nitrate. To order to utilize EAs with less positive redox potential, such as nitrite and fumarate, S. oneidensis must enter the stationary phase, when oxygen respiration becomes unfavorable. In addition, we demonstrated that during aerobic respiration the cytochrome bd oxidase confers S. oneidensis resistance to nitrite, which likely functions via nitric oxide (NO). PMID:23626841

Zhang, Haiyan; Fu, Huihui; Wang, Jixuan; Sun, Linlin; Jiang, Yaoming; Zhang, Lili; Gao, Haichun

2013-04-23

49

Impacts of Nitrate and Nitrite on Physiology of Shewanella oneidensis  

PubMed Central

Shewanella oneidensis exhibits a remarkable versatility in anaerobic respiration, which largely relies on its diverse respiratory pathways. Some of these are expressed in response to the existence of their corresponding electron acceptors (EAs) under aerobic conditions. However, little is known about respiration and the impact of non-oxygen EAs on the physiology of the microorganism when oxygen is present. Here we undertook a study to elucidate the basis for nitrate and nitrite inhibition of growth under aerobic conditions. We discovered that nitrate in the form of NaNO3 exerts its inhibitory effects as a precursor to nitrite at low concentrations and as an osmotic-stress provider (Na+) at high concentrations. In contrast, nitrite is extremely toxic, with 25 mM abolishing growth completely. We subsequently found that oxygen represses utilization of all EAs but nitrate. To order to utilize EAs with less positive redox potential, such as nitrite and fumarate, S. oneidensis must enter the stationary phase, when oxygen respiration becomes unfavorable. In addition, we demonstrated that during aerobic respiration the cytochrome bd oxidase confers S. oneidensis resistance to nitrite, which likely functions via nitric oxide (NO).

Zhang, Haiyan; Fu, Huihui; Wang, Jixuan; Sun, Linlin; Jiang, Yaoming; Zhang, Lili; Gao, Haichun

2013-01-01

50

The Evaluation of the Content of Nitrates and Nitrites in Food Products for Infants  

Microsoft Academic Search

Nitrates and nitrites in 27 types of food products for infants from three commercial brands, of normal consumption in the Canary Islands, were determined. The assay of nitrates and nitrites in the solution obtained from the extraction process was undertaken according to the rules of AFNOR. Nitrites were evaluated by means of the Griess response and nitrates were evaluated in

A. Hardisson; A. González Padrón; I. Fr??as; J. I. Reguera

1996-01-01

51

Photochemistry of nitrite and nitrate in aqueous solution: a review  

Microsoft Academic Search

It has long been known that the photolysis of nitrite and nitrate solutions results in the formation of OH radicals. The mechanism of NO3? photolysis has been the subject of considerable controversy in the literature, however. This review summarizes the experimental work on NO2? and NO3? photolysis in the context of recent advances in the understanding of the chemistry of

John Mack; James R. Bolton

1999-01-01

52

Accumulations of Nitrite and Nitrate in the Tissues of Penaeus monodon Exposed to a Combined Environment of Elevated Nitrite and Nitrate  

Microsoft Academic Search

Penaeus monodon (11.86 ± 0.63 g) exposed individually to six different nitrite and nitrate regimes [nitrite at 0.002 (control), 0.360, and\\u000a 1.455 mM combined with nitrate at 0.005 (control) and 7.275 mM] in 25 ppt sea water were examined for the nitrite and nitrate\\u000a concentrations in tissues and nitrite uptake and nitrate uptake after 24 h in 25.3°C. In P.

S.-Y. Cheng; J.-C. Chen

2002-01-01

53

Uptake, elimination and effects of nitrite and nitrate in freshwater crayfish ( Astacus astacus)  

Microsoft Academic Search

Elevated concentrations of nitrite and\\/or nitrate are a potential problem in aquatic ecosystems. Freshwater crayfish, Astacus astacus, were exposed to 1 mM nitrite or 1 mM nitrate in order to study uptake and physiological effects of these ions. Additionally, recovery from nitrite intoxication was investigated. Crayfish exposed to 1 mM ambient nitrite accumulated nitrite in the haemolymph to a concentration

Frank B. Jensen

1996-01-01

54

Evolutionary relationships among ammonia- and nitrite-oxidizing bacteria.  

PubMed Central

Comparative 16S rRNA sequencing was used to evaluate phylogenetic relationships among selected strains of ammonia- and nitrite-oxidizing bacteria. All characterized strains were shown to be affiliated with the proteobacteria. The study extended recent 16S rRNA-based studies of phylogenetic diversity among nitrifiers by the comparison of eight strains of the genus Nitrobacter and representatives of the genera Nitrospira and Nitrospina. The later genera were shown to be affiliated with the delta subdivision of the proteobacteria but did not share a specific relationship to each other or to other members of the delta subdivision. All characterized Nitrobacter strains constituted a closely related assemblage within the alpha subdivision of the proteobacteria. As previously observed, all ammonia-oxidizing genera except Nitrosococcus oceanus constitute a monophyletic assemblage within the beta subdivision of the proteobacteria. Errors in the 16S rRNA sequences for two strains previously deposited in the databases by other investigators (Nitrosolobus multiformis C-71 and Nitrospira briensis C-128) were corrected. Consideration of physiology and phylogenetic distribution suggested that nitrite-oxidizing bacteria of the alpha and gamma subdivisions are derived from immediate photosynthetic ancestry. Each nitrifier retains the general structural features of the specific ancestor's photosynthetic membrane complex. Thus, the nitrifiers, as a group, apparently are not derived from an ancestral nitrifying phenotype.

Teske, A; Alm, E; Regan, J M; Toze, S; Rittmann, B E; Stahl, D A

1994-01-01

55

Simultaneous Determination of Nitrate and Nitrite in Biological Samples by Multichannel Flow Injection Analysis  

Microsoft Academic Search

An automated method for the simultaneous determination of nitrite and nitrate in biological samples by using a multichannel flow injection analyzer has been developed. The method was based on the reaction of nitrite with Greiss reagent. The sample solution was injected and equally divided into two channels; channel one (1) represented total nitrite obtained by cadmium reduction of nitrate to

Phillip F. Pratt; Kasem Nithipatikom; William B. Campbell

1995-01-01

56

Changes in nitrate and nitrite concentrations over 24h for sweet basil and scallions.  

PubMed

Nitrate and nitrite concentrations were determined for sweet basil and scallions over 24h to determine if time of sampling or harvest impacts concentrations in raw vegetables. Also, nitrate and nitrite concentrations were determined separately for various edible parts of these plants. Basil had significant changes in nitrate and nitrite concentrations over a 24h period. Nitrate was correlated to changes in light intensity with a 3h lag time. The highest nitrate concentrations in basil (2777 ppm) occurred around 3h after the light intensity peaked and had low values (165-574 ppm) during the dark period. The scallion nitrate and nitrite concentrations were always low but nitrate showed a peak a few hours before sunrise. Nitrate and nitrite concentrations in some raw vegetables may be reduced by harvesting at the best time of day for each type of plant. Nitrate concentrations were different in the edible plant parts tested. PMID:23122149

Chang, Audrey Chingzu; Yang, Tsz Yi; Riskowski, Gerald L

2012-09-12

57

Toxicity of Ammonia and Nitrite to Sunshine Bass in Selected Environments  

Microsoft Academic Search

The effects of environmental calcium and salinity on toxicities of ammonia and nitrite for sunshine bass (female Morone chrysops × male M. saxatilis) were investigated, and the effects of pH, sodium chloride, and calcium chloride on uptake and depuration of ammonia and nitrite were characterized. The concentration of un-ionized ammonia-nitrogen (UIA-N) lethal to 50% of the fish within 96 h

C. R. Weirich; J. R. Tomasso; T. I. J. Smith

1993-01-01

58

The Nitrate–Nitrite–Nitric Oxide Pathway in Mammals  

Microsoft Academic Search

\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Accumulating evidence suggests that the molecules nitrite and nitrate can be metabolized in vivo to form NO and other bioactive\\u000a nitrogen oxides.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Commensal bacteria play a central role in the bioactivation of nitrate in an entero-salivary bioactivation pathway.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a A number of nitrite reductase enzymes reduce nitrite to bioactive NO along a physiological oxygen and pH gradient.\\u000a \\u000a \\u000a \\u000a \\u000a • 

Jon O. Lundberg; Eddie Weitzberg; Sruti Shiva; Mark T. Gladwin

59

Blue Light, a Positive Switch Signal for Nitrate and Nitrite Uptake by the Green Alga Monoraphidium braunii1  

PubMed Central

Blue light was shown to regulate the utilization of oxidized nitrogen sources by green algae, both by activating nitrate reductase and promoting nitrite reductase biosysnthesis (MA Quiñones, PJ Aparicio [1990] Inorganic Nitrogen in Plants and Microorganisms, Springer-Verlag, Berlin, pp 171-177; MA Quiñones, PJ Aparicio [1990] Photochem Photobiol 51: 681-692). The data reported herein show that, when cells of Monoraphidium braunii at pH 8, containing both active nitrate reductase and nitrite reductase, were sparged with CO2-free air and irradiated with strong background red light, they took up oxidized nitrogen sources only when PAR comprised blue light. The activation of the transport system(s) of either both nitrate and nitrite was very quick and elicited by low irradiance blue light. In fact, blue light appears to act as a switch signal from the environment, since the uptake of these anions immediately ceased when this radiation was turned off. The requirement of blue light for nitrate uptake was independent of the availability of CO2 to cells. However, cells under high CO2 tensions, although they showed an absolute blue light requirement to initially establish the uptake of nitrite, as they gained carbon skeletons to allocate ammonia, gradually increased their nitrite uptake rates in the subsequent red light intervals. Under CO2-free atmosphere, cells irradiated with strong background red light of 660 nanometers only evolved oxygen when they were additionally irradiated with low irradiance blue light and either nitrate or nitrite was present in the media to provide electron acceptors for the photosynthetic reaction.

Aparicio, Pedro J.; Quinones, Miguel A.

1991-01-01

60

Blue Light, a Positive Switch Signal for Nitrate and Nitrite Uptake by the Green Alga Monoraphidium braunii.  

PubMed

Blue light was shown to regulate the utilization of oxidized nitrogen sources by green algae, both by activating nitrate reductase and promoting nitrite reductase biosysnthesis (MA Quiñones, PJ Aparicio [1990] Inorganic Nitrogen in Plants and Microorganisms, Springer-Verlag, Berlin, pp 171-177; MA Quiñones, PJ Aparicio [1990] Photochem Photobiol 51: 681-692). The data reported herein show that, when cells of Monoraphidium braunii at pH 8, containing both active nitrate reductase and nitrite reductase, were sparged with CO(2)-free air and irradiated with strong background red light, they took up oxidized nitrogen sources only when PAR comprised blue light. The activation of the transport system(s) of either both nitrate and nitrite was very quick and elicited by low irradiance blue light. In fact, blue light appears to act as a switch signal from the environment, since the uptake of these anions immediately ceased when this radiation was turned off. The requirement of blue light for nitrate uptake was independent of the availability of CO(2) to cells. However, cells under high CO(2) tensions, although they showed an absolute blue light requirement to initially establish the uptake of nitrite, as they gained carbon skeletons to allocate ammonia, gradually increased their nitrite uptake rates in the subsequent red light intervals. Under CO(2)-free atmosphere, cells irradiated with strong background red light of 660 nanometers only evolved oxygen when they were additionally irradiated with low irradiance blue light and either nitrate or nitrite was present in the media to provide electron acceptors for the photosynthetic reaction. PMID:16667993

Aparicio, P J; Quiñones, M A

1991-02-01

61

Nitrite reductase activity of sulphate-reducing bacteria prevents their inhibition by nitrate-reducing, sulphide-oxidizing bacteria.  

PubMed

Sulphate-reducing bacteria (SRB) can be inhibited by nitrate-reducing, sulphide-oxidizing bacteria (NR-SOB), despite the fact that these two groups are interdependent in many anaerobic environments. Practical applications of this inhibition include the reduction of sulphide concentrations in oil fields by nitrate injection. The NR-SOB Thiomicrospira sp. strain CVO was found to oxidize up to 15 mM sulphide, considerably more than three other NR-SOB strains that were tested. Sulphide oxidation increased the environmental redox potential (Eh) from -400 to +100 mV and gave 0.6 nitrite per nitrate reduced. Within the genus Desulfovibrio, strains Lac3 and Lac6 were inhibited by strain CVO and nitrate for the duration of the experiment, whereas inhibition of strains Lac15 and D. vulgaris Hildenborough was transient. The latter had very high nitrite reductase (Nrf) activity. Southern blotting with D. vulgaris nrf genes as a probe indicated the absence of homologous nrf genes from strains Lac3 and Lac6 and their presence in strain Lac15. With respect to SRB from other genera, inhibition of the known nitrite reducer Desulfobulbus propionicus by strain CVO and nitrate was transient, whereas inhibition of Desulfobacterium autotrophicum and Desulfobacter postgatei was long-lasting. The results indicate that inhibition of SRB by NR-SOB is caused by nitrite production. Nrf-containing SRB can overcome this inhibition by further reducing nitrite to ammonia, preventing a stalling of the favourable metabolic interactions between these two bacterial groups. Nrf, which is widely distributed in SRB, can thus be regarded as a resistance factor that prevents the inhibition of dissimilatory sulphate reduction by nitrite. PMID:12823193

Greene, E A; Hubert, C; Nemati, M; Jenneman, G E; Voordouw, G

2003-07-01

62

Nitrate and vitamin C from fruits and vegetables: Impact of intake variations on nitrate and nitrite excretions of humans  

Microsoft Academic Search

The objective of the study was to determine nitrate + nitrite excretions of human subjects fed variable amounts of nitrates and nitrites and vitamin C from fruits and vegetables. During four, randomly-arranged experimental periods of seven days each, the 12 apparently healthy, adult human subjects consumed laboratory controlled, constant, diets which were systematically varied in kinds of fruits and vegetable

C. Bednar; C. Kies

1994-01-01

63

Nitrification with high nitrite accumulation for the treatment of wastewater with high ammonia concentration  

Microsoft Academic Search

The objective of this paper was to determine the best conditions for partial nitrification with nitrite accumulation of simulated industrial wastewater with high ammonia concentration, lowering the total oxygen needed in the nitrification step, which may mean great saving in aeration. Dissolved oxygen (DO) concentration and pH were selected as operational parameters to study the possibility of nitrite accumulation not

G Ruiz; D Jeison; R Chamy

2003-01-01

64

Selective inhibition of ammonia oxidation and nitrite oxidation linked to N2O emission with activated sludge and enriched nitrifiers.  

PubMed

Nitrification in wastewater treatment emits a significant amount of nitrous oxide (N2O), which is one of the major greenhouse gases. However, the actual mechanism or metabolic pathway is still largely unknown. Selective nitrification inhibitors were used to determine the nitrification steps responsible for N2O emission with activated sludge and enriched nitrifiers. Allylthiourea (86 microM) completely inhibited ammonia oxidation and N2O emission both in activated sludge and enriched nitrifiers. Sodium azide (24 microM) selectively inhibited nitrite oxidation and it led to more N2O emission than the control experiment both in activated sludge and enriched nitrifiers. The inhibition tests showed that N2O emission was mainly related to the activity of ammonia oxidizers in aerobic condition, and the inhibition of ammonia monooxygenase completely blocked N2O emission. On the other hand, N2O emission increased significantly as the nitrogen flux from nitrite to nitrate was blocked by the selective inhibition of nitrite oxidation. PMID:23648864

Ali, Toor Umair; Kim, Minwook; Kim, Dong-Jin

2013-05-01

65

The use and control of nitrate and nitrite for the processing of meat products  

Microsoft Academic Search

Nitrate and nitrite are used for the purpose of curing meat products. In most countries the use of both substances, usually added as potassium or sodium salts, is limited. Either the ingoing or the residual amounts are regulated by laws.The effective substance is nitrite acting primarily as an inhibitor for some microorganisms.Nitrite added to a batter of meat is partially

Karl-Otto Honikel

2008-01-01

66

Toluene nitration in irradiated nitric acid and nitrite solution  

SciTech Connect

The kinetics, mechanisms, and stable products produced for the aryl alkyl mild ortho-para director - toluene, in irradiated nitric acid and neutral nitrite solutions were investigated using ?, and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection was primarily used to assess the stable reaction products. GC-MS and LC-MS were used to confirm the results from HPLC. Free-radical nitration reaction products were found in irradiated acidic and neutral media. In acidic medium, the ring substitution and side chain substitution and oxidation produced different nitro products. In ring substitution, nitrogen oxide radicals were added mainly to hydroxyl radical-produced cyclohexadienyl radical, and in side chain substitution they were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite toluene solution, radiolytic ring nitration products approached a statistically random distribution, suggesting a free-radical reaction involving addition of the •NO2 radical.

Gracy Elias; Bruce J. Mincher; Stephen P. Mezyk; Jim Muller; Leigh R. Martin

2011-04-01

67

Effects of nitrite and nitrate on DNA damage induced by ultraviolet light.  

PubMed

UV light is a major cause of human skin cancers. Nitrite and nitrate are well-known potential risk factors for gastric cancer. Little attention has been paid to the relationship between UV light and nitrite or nitrate on cancer. We examined the effects of nitrite and nitrate on the damage to nucleosides and DNA induced by UV light from a mercury lamp and by sunlight at neutral pH. A biologically relevant dose of nitrite and nitrate increased the generation of nucleobases and malondialdehyde on the reaction of nucleosides and DNA with UV light. The efficiency of nitrite enhancing the reaction was higher than that of nitrate at low doses. The contribution of the hydroxyl radical as the reactive species was suggested from the results of the inhibitory effects of hydroxyl radical scavengers. Nitrite and nitrate also enhanced the formation of nucleobases and malondialdehyde from DNA induced by sunlight. In the presence of 5 muM nitrite, the concentration in human skin cells, the product yields by sunlight were 5-10-fold greater than those in the absence of nitrite. The addition of 80 muM NO(3)(-), a concentration in human skin cells, also increased the yields significantly. Nitrite and nitrate may play a role in enhancing the genotoxic effects of UV light in humans. PMID:16544952

Suzuki, Toshinori; Inukai, Michiyo

2006-03-01

68

Intake and risk assessment of nitrate and nitrite from New Zealand foods and drinking water  

Microsoft Academic Search

Exposure to excess nitrite is a potential health risk for humans. One hundred meat and processed foods and 100 vegetable samples purchased from New Zealand retail outlets were prepared as for consumption and analysed for nitrite and nitrate concentration using a standard, validated methodology. Nitrate concentrations ranged from less than the limit of detection (LOD?=?5?mg?kg) in cheddar cheese and cream

B. M. Thomson; C. J. Nokes; P. J. Cressey

2007-01-01

69

Automated simultaneous monitoring of nitrate and nitrite in surface water by sequential injection analysis.  

PubMed

A fully automated procedure based on Sequential Injection Analysis (SIA) methodology for simultaneous monitoring of nitrate and nitrite in surface water samples is described. Nitrite was determined directly using the Griess diazo-coupling reaction and the formed azo dye was measured at 540 nm in the flow cell of the fibre-optic spectrophotometer. Nitrate zone was passed through a reducing mini-column containing copperised-cadmium. After the reduction of nitrate into nitrite the sample was aspirated by flow reversal to the holding coil, treated with the reagent and finally passed through the flow cell. The calibration curve was linear over the range 0.05-1.00 mg N l(-1) of nitrite and 0.50-50.00 mg N l(-1) of nitrate; correlation coefficients were 0.9993 and 0.9988 for nitrite and nitrate, respectively. Detection limits were 0.015 and 0.10 mg N l(-1) for nitrite and nitrate, respectively. The relative standard deviation (RSD) values (n = 3) were 1.10% and 1.32% for nitrite and nitrate, respectively. The total time of one measuring cycle was 250 s, thus the sample throughput was about 14 h(-1). Nitrate and nitrite were determined in the real samples of surface water, and the results have been compared with those obtained by two other flow methods; flow injection analysis based on the same reactions and isotachophoretic determination used in a routine environmental control laboratory. PMID:12146865

Legnerová, Zlatuse; Solich, Petr; Sklenárová, Hana; Satínský, Dalibor; Karlícek, Rolf

2002-06-01

70

Carbon-Fiber Nitrite Microsensor for In Situ Biofilm Monitoring  

EPA Science Inventory

During nitrification, nitrite is produced as an intermediate when ammonia is oxidized to nitrate. It is well established that nitrifying biofilm are involved in nitrification episodes in chloraminated drinking water distribution systems with nitrite accumulation occurring during...

71

Carbon-Fiber Nitrite Microsensor for In Situ Biofilm Monitoring  

EPA Science Inventory

During nitrification, nitrite is produced as an intermediate when ammonia is oxidized to nitrate. It is well established that nitrifying biofilm are involved in nitrification episodes in chloraminated drinking water distribution systems with nitrite accumulation occurring during ...

72

Determination of nitrate, nitrite and perchlorate anions in meat, milk and their products consumed in Hatay region in Turkey  

Microsoft Academic Search

Nitrates and nitrites added to food can cause formation of cancerous N-nitroso compounds, whereas exposure to perchlorate is especially emphasised as an important risk factor for newborns’ health. In this study, nitrate, nitrite and perchlorate concentrations in meat and milk products consumed in the Hatay region of Turkey were determined. Nitrate and nitrite were analysed with a spectrophotometric method, and

?ana Sungur; Muhammet Meriç Atan

2012-01-01

73

Effect of Nitrite/Nitrate concentrations on Corrosivity of Washed Precipitate  

SciTech Connect

Cyclic polarization scans were performed using A-537 carbon steel in simulated washed precipitate solutions of various nitrite and nitrate concentrations. The results of this study indicate that nitrate is an aggressive anion in washed precipitate. Furthermore, a quantitative linear log-log relationship between the minimum effective nitrite concentration and the nitrate concentration was established for washed precipitate with other ions at their average compositions.

Congdon, J.W.

2001-03-28

74

Chemical compound containing a superoxide scavenger and an organic nitrate or nitrite moiety  

US Patent & Trademark Office Database

Compounds for use in the treatment of heart disease include a superoxide scavenger and an organic nitrate or nitrite moiety. The compounds can be represented by the formula (A)n(B)m, in which A is a superoxide scavenger, B is an organic nitrate or organic nitrite moiety, and n and m are values between 1 and 8. These compounds do not suffer from the problem of patient tolerance that is associated with the use of conventional agents such as organic nitrates.

Zhang; Zhi (London, GB); Naughton; Declan P. (Brighton, GB); Sumi; Yoshihiko (Tokyo, JP); Imaizumi; Atsushi (Tokyo, JP)

2002-02-12

75

Dietary Nitrate and Nitrite Intake and Non-Hodgkin Lymphoma Survival  

PubMed Central

Nitrate and nitrite are precursors in the formation of N-nitroso compounds. We recently found a 40% increased risk of NHL with higher dietary nitrite intake and significant increases in risk for follicular and T-cell lymphoma. It is possible that these compounds also affect NHL prognosis by enhancing cancer progression in addition to development by further impairing immune system function. To test the hypothesis that nitrate and nitrite intake affects NHL survival, we evaluated the association in study participants that have been followed post-disease diagnosis in a population-based case-control study among women in Connecticut. We did not observe a significant increasing trend of mortality for NHL overall or by subtype for nitrate or nitrite intake for deaths from NHL or death from any cause, although a borderline significant protective trend was observed for follicular lymphoma with increasing nitrate intake. We did not identify a difference in overall survival for nitrate (P = 0.39) or for nitrite (P = 0.66) or for NHL specific survival for nitrate (P = 0.96) or nitrite (P = 0.17). Thus, our null findings do not confer support for the possibility that dietary nitrate and nitrite intake impacts NHL survival by promoting immune unresponsiveness.

Aschebrook-Kilfoy, Briseis; Ward, Mary H.; Zheng, Tongzhang; Holford, Theodore R.; Boyle, Peter; Leaderer, Brian; Zhang, Yawei

2012-01-01

76

Dietary nitrate and nitrite intake and non-Hodgkin lymphoma survival.  

PubMed

Nitrate and nitrite are precursors in the formation of N-nitroso compounds. We recently found a 40% increased risk of NHL with higher dietary nitrite intake and significant increases in risk for follicular and T-cell lymphoma. It is possible that these compounds also affect NHL prognosis by enhancing cancer progression in addition to development by further impairing immune system function. To test the hypothesis that nitrate and nitrite intake affects NHL survival, we evaluated the association in study participants that have been followed post-disease diagnosis in a population-based case-control study among women in Connecticut. We did not observe a significant increasing trend of mortality for NHL overall or by subtype for nitrate or nitrite intake for deaths from NHL or death from any cause, although a borderline significant protective trend was observed for follicular lymphoma with increasing nitrate intake. We did not identify a difference in overall survival for nitrate (P = 0.39) or for nitrite (P = 0.66) or for NHL specific survival for nitrate (P = 0.96) or nitrite (P = 0.17). Thus, our null findings do not confer support for the possibility that dietary nitrate and nitrite intake impacts NHL survival by promoting immune unresponsiveness. PMID:22420290

Aschebrook-Kilfoy, Briseis; Ward, Mary H; Zheng, Tongzhang; Holford, Theodore R; Boyle, Peter; Leaderer, Brian; Zhang, Yawei

2012-03-16

77

Dietary nitrite and nitrate: a review of potential mechanisms of cardiovascular benefits  

PubMed Central

Purpose In the last decade, a growing scientific and medical interest has emerged toward cardiovascular effects of dietary nitrite and nitrate; however, many questions concerning their mode of action(s) remain unanswered. In this review, we focus on multiple mechanisms that might account for potential cardiovascular beneficial effects of dietary nitrite and nitrate. Results Beneficial changes to cardiovascular health from dietary nitrite and nitrate might result from several mechanism(s) including their reduction into nitric oxide, improvement in endothelial function, vascular relaxation, and/or inhibition of the platelet aggregation. From recently obtained evidence, it appears that the longstanding concerns about the toxicity of oral nitrite or nitrate are overstated. Conclusion Dietary nitrite and nitrate may have cardiovascular protective effects in both healthy individuals and also those with cardiovascular disease conditions. A role for nitrite and nitrate in nitric oxide biosynthesis and/or in improving nitric oxide bioavailability may eventually provide a rationale for using dietary nitrite and nitrate supplementation in the treatment and prevention of cardiovascular diseases.

Machha, Ajay

2012-01-01

78

Anisole Nitration During Gamma-Irradiation of Aqueous Nitrite and Nitrate Solutions: Free Radical Versus Ionic Mechanisms  

SciTech Connect

The nitration of aromatic compounds in the condensed phase is of interest to nuclear waste treatment applications. This chapter discusses our investigation of radiolytic aromatic nitration mechanisms in the condensed phase toward understanding the nitration products created during nuclear fuel reprocessing. The nitration reactions of anisole, a model aromatic compound, were studied in ?-irradiated acidic nitrate, neutral nitrate, and neutral nitrite solutions. The nitrated anisole product distributions were the same with and without radiation in acidic solution, although more products were formed with radiation. In the irradiated acidic condensed phase, radiation-enhanced nitrous acid-catalyzed nitrosonium ion electrophilic aromatic substitution followed by oxidation reactions dominated over radical addition reactions. Neutral nitrate anisole solutions were dominated by mixed nitrosonium/nitronium ion electrophilic aromatic substitution reactions, but with lower product yields. Irradiation of neutral nitrite anisole solution resulted in a statistical substitution pattern for nitroanisole products, suggesting non-electrophilic free radical reactions involving the •NO2 radical.

Gracy Elias; Bruce J. Mincher; Leigh R. Martin; Stephen P. Mezyk; Thomas D. Cullen

2010-04-01

79

Plasma nitrate and nitrite are increased by a high-nitrate supplement but not by high-nitrate foods in older adults.  

PubMed

Little is known about the effect of dietary nitrate on the nitrate/nitrite/nitric oxide cycle in older adults. We examined the effect of a 3-day control diet vs high-nitrate diet, with and without a high-nitrate supplement (beetroot juice), on plasma nitrate and nitrite kinetics and blood pressure using a randomized 4-period crossover controlled design. We hypothesized that the high-nitrate diet would show higher levels of plasma nitrate/nitrite and lower blood pressure compared with the control diet, which would be potentiated by the supplement. Participants were 8 normotensive older men and women (5 female, 3 male, 72.5 ± 4.7 years old) with no overt disease or medications that affect nitric oxide metabolism. Plasma nitrate and nitrite levels and blood pressure were measured before and hourly for 3 hours after each meal. The mean daily changes in plasma nitrate and nitrite were significantly different from baseline for both control diet + supplement (P < .001 and P = .017 for nitrate and nitrite, respectively) and high-nitrate diet + supplement (P = .001 and P = .002), but not for control diet (P = .713 and P = .741) or high-nitrate diet (P = .852 and P = .500). Blood pressure decreased from the morning baseline measure to the three 2-hour postmeal follow-up time points for all treatments, but there was no main effect for treatment. In healthy older adults, a high-nitrate supplement consumed at breakfast elevated plasma nitrate and nitrite levels throughout the day. This observation may have practical utility for the timing of intake of a nitrate supplement with physical activity for older adults with vascular dysfunction. PMID:22464802

Miller, Gary D; Marsh, Anthony P; Dove, Robin W; Beavers, Daniel; Presley, Tennille; Helms, Christine; Bechtold, Erika; King, S Bruce; Kim-Shapiro, Daniel

2012-03-01

80

Anisole nitration during gamma-irradiation of aqueous nitrite and nitrate solutions: Free radical versus ionic mechanisms  

SciTech Connect

Radiolytic aromatic nitration mechanisms in the condensed phase are ubiquitous, and especially of interest in atmospheric aerosol chemistry, water treatment by advanced oxidation technologies, and nuclear fuel reprocessing. Here, the radiolytically-induced nitration reactions of anisole, the simplest aryl alkyl ether, were investigated in ?-irradiated acidic nitrate solution, and in neutral nitrate and nitrite solutions. The nitrated anisole product distribution was the same with and without radiation in acidic solution, although more products were formed as a result of irradiation. This suggests that the mechanism of nitration in acidic solution is nitronium ion- induced electrophilic aromatic substitution. The rate of production of nitrated products in neutral nitrate solution was much lower, although the distribution of isomers was similar to that expected for nitronium ion electrophilic nitration. In contrast, the product distribution in neutral nitrite solution approached a statistically random substitution pattern, suggesting a non-electrophilic free radical reaction involving •NO2 radical. When hydroxyl radical (•OH) was scavenged by varying the initial nitrite concentration, the concentration of nitrated products increased with increasing nitrite, indicating that the reaction was probably one of direct •NO2 radical addition. However, this latter mechanism will not be important in acidic solutions, such as those often encountered in atmospheric aerosols or ?-irradiated nuclear fuel reprocessing solutions, due to low amounts of produced •NO2 radical and the low reaction rate constants for the •NO2 radical with aromatic compounds.

Gracy Elias; Bruce J. Mincher; Leigh R. Martin; Stephen P. Mezyk; Thomas Cullen

2010-04-01

81

Solubilities of sodium nitrate, sodium nitrite, and sodium aluminate in simulated nuclear waste  

SciTech Connect

Solubilities were determined for sodium nitrate, sodium nitrite, and sodium aluminate in synthetic nuclear waste liquor. Solubilities were determined as a function of temperature and solution composition (concentrations of sodium hydroxide, sodium nitrate, sodium nitrite, and sodium aluminate). Temperature had the greatest effect on the solubilities of sodium nitrate and sodium nitrite and a somewhat lesser effect on sodium aluminate solubility. Hydroxide had a great effect on the solubilities of all three salts. Other solution components had minor effects. 2 references, 8 figures, 11 tables.

Reynolds, D.A.; Herting, D.L.

1984-09-01

82

A simple miniaturised photometrical method for rapid determination of nitrate and nitrite in freshwater  

Microsoft Academic Search

A rapid, simple miniaturised photometrical method was developed for the determination of nitrate and\\/or nitrite in freshwater samples. All procedures, including sample buffering, reduction by copperised cadmium granules, colour development and absorbance determination, were completed in a 96-well microplate. The factors governing the nitrate reduction and its recovery were investigated in detail, and the optimised analysing conditions were established. Nitrate

Xinhai Tu; Bangding Xiao; Jian Xiong; Xudong Chen

2010-01-01

83

Temporal and spatial regulation of nitrate reductase and nitrite reductase in greening maize leaves  

Microsoft Academic Search

The temporal and spatial regulation of nitrate reductase (NR), a cytosolic enzyme, and nitrite reductase (NIR), a chloroplastic enzyme, was examined in first leaf of maize seedlings. The induction of NR and NIR activity showed a biphasic response with reference to exogenous concentration of nitrate, which probably resulted from the biphasic uptake of nitrate in seedlings. The time course of

Rupali Datta; Rameshwar Sharma

1999-01-01

84

Niche differentiation of ammonia oxidizers and nitrite oxidizers in rice paddy soil.  

PubMed

The dynamics of populations and activities of ammonia-oxidizing and nitrite-oxidizing microorganisms were investigated in rice microcosms treated with two levels of nitrogen. Different soil compartments (surface, bulk, rhizospheric soil) and roots (young and old roots) were collected at three time points (the panicle initiation, heading and maturity periods) of the season. The population dynamics of bacterial (AOB) and archaeal (AOA) ammonia oxidizers was assayed by determining the abundance (using qPCR) and composition (using T-RFLP and cloning/sequencing) of their amoA genes (coding for a subunit of ammonia monooxygenase), that of nitrite oxidizers (NOB) by quantifying the nxrA gene (coding for a subunit of nitrite oxidase of Nitrobacter spp.) and the 16S rRNA gene of Nitrospira spp. The activity of the nitrifiers was determined by measuring the rates of potential ammonia oxidation and nitrite oxidation and by quantifying the copy numbers of amoA and nxrA transcripts. Potential nitrite oxidation activity was much higher than potential ammonia oxidation activity and was not directly affected by nitrogen amendment demonstrating the importance of ammonia oxidizers as pace makers for nitrite oxidizer populations. Marked differences in the distribution of bacterial and archaeal ammonia oxidizers, and of Nitrobacter-like and Nitrospira-like nitrite oxidizers were found in the different compartments of planted paddy soil indicating niche differentiation. In bulk soil, ammonia-oxidizing bacteria (Nitrosospira and Nitrosomonas) were at low abundance and displayed no activity, but in surface soil their activity and abundance was high. Nitrite oxidation in surface soil was dominated by Nitrospira spp. By contrast, ammonia-oxidizing Thaumarchaeota and Nitrobacter spp. seemed to dominate nitrification in rhizospheric soil and on rice roots. In contrast to soil compartment, the level of N fertilization and the time point of sampling had only little effect on the abundance, composition and activity of the nitrifying communities. The results of our study show that in rice fields population dynamics and activity of nitrifiers is mainly differentiated by the soil compartments rather than by nitrogen amendment or season. PMID:23437806

Ke, Xiubin; Angel, Roey; Lu, Yahai; Conrad, Ralf

2013-02-25

85

Risk of non-Hodgkin lymphoma and nitrate and nitrite from the diet in Connecticut women.  

PubMed

It has been estimated that 65,980 individuals were diagnosed with non-Hodgkin lymphoma (NHL) and 19,500 died from NHL in the United States in 2009. Although established risk factors such as immunodeficiency and viral infections may be responsible for a portion of the cases, the majority of NHL cases remain unexplained. Dietary nitrate and nitrite intake are exposures of particular interest for NHL risk as they are precursors in the endogenous formation of N-nitroso compounds, which cause lymphomas in animal studies. We investigated NHL risk overall and by histologic type in relation to dietary nitrate and nitrite intake in a population-based case-control study of 1,304 women in Connecticut. Nitrate and nitrite intake were assessed using a 120-item food frequency questionnaire. We found no association between risk of NHL overall and dietary nitrate and a slightly increased risk of NHL with higher dietary nitrite intake (highest vs. lowest intake quartile OR = 1.4; 95% CI: 0.9-2.2). When we evaluated intake by subtype, a significant positive trend was observed for follicular lymphoma and nitrate (p-trend = 0.04) and nitrite (p-trend < 0.01) with an over twofold risk in the highest nitrite intake quartile (OR = 2.3; 95% CI: 1.1-4.9). An increased risk in the highest quartile of nitrite intake was also observed for T-cell lymphoma (OR = 3.4; 95% CI: 1.0-11.9). Animal products containing nitrite were more strongly associated with risk of follicular lymphoma; whereas, both animal and plant sources of nitrite were associated with elevated ORs for T-cell lymphoma. Our results confirm a previous finding for nitrite intake and NHL risk and highlight the importance of evaluating histologic type. We conclude that these results should be replicated in a larger study with data on drinking water as well as dietary sources of nitrate intake. PMID:20204494

Kilfoy, Briseis A; Ward, Mary H; Zheng, Tongzhang; Holford, Theodore R; Boyle, Peter; Zhao, Ping; Dai, Min; Leaderer, Brian; Zhang, Yawei

2010-03-05

86

Nitrate and Nitrite Reduction by Microorganisms Embedded in a Filter Paper Incubated Aerobically  

PubMed Central

Pseudomonas aeruginosa, grown to steric saturation between the cellulose fibers of a filter paper, reduced nitrate or nitrite or both when the cell-filled paper was washed, transferred to phosphate buffer, nitrate, or nitrite or both, and glucose agar plates, and incubated under aerobiosis as resting cells. The biological nature of the reduction was ascertained by the use of nitrate and nitrite reductaseless mutants. The mesh of cellulose fibers was necessary to create a sufficient barrier to oxygen diffusion, since denitrification was not obtained within large and thick colonies of P. aeruginosa. When a soil suspension was used to inoculate the filter paper, ammonium and nitrite accumulated. Concomitant to nitrate reduction, the total nonvolatile inorganic nitrogen decreased and then increased as if part of it was immobilized to be subsequently mineralized.

Hilali, A.; Molina, J. A. E.

1979-01-01

87

Parallel plate electrochemical reactor model for the destruction of nitrate and nitrite in alkaline waste solutions.  

National Technical Information Service (NTIS)

The nitrate and nitrite species present in liquid radioactive waste solutions must be destroyed before permanent disposal of the waste can be accomplished. This process can simultaneously remove hazardous compounds and reduce the volume of the waste. A di...

D. T. Hobbs D. H. Coleman R. E. White

1994-01-01

88

NarK is a nitrite-extrusion system involved in anaerobic nitrate respiration by Escherichia coli  

Microsoft Academic Search

Escherichia coli can use nitrate as a terminal electron acceptor for anaerobic respiration. A polytopic membrane protein, termed NarK, has been implicated in nitrate uptake and nitrite excretion and is thought to function as a nitrate\\/nitrite antiporter. The longest-lived radioactive isotope of nitrogen, 13N-nitrate (half-life = 9.96 min) and the nitrite-sensitive fluorophore N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide have now been used to define

John J. Rowe; Trees Ubbink-Kok; Douwe Molenaar; Wil N. Konings; Arnold J. M. Driessen

1994-01-01

89

Dietary Nitrate and Nitrite Intake and Non-Hodgkin Lymphoma Survival  

Microsoft Academic Search

Nitrate and nitrite are precursors in the formation of N-nitroso compounds. We recently found a 40% increased risk of NHL with higher dietary nitrite intake and significant increases in risk for follicular and T-cell lymphoma. It is possible that these compounds also affect NHL prognosis by enhancing cancer progression in addition to development by further impairing immune system function. To

Briseis Aschebrook-Kilfoy; Mary H. Ward; Tongzhang Zheng; Theodore R. Holford; Peter Boyle; Brian Leaderer; Yawei Zhang

2012-01-01

90

Effects of nitrite and nitrate on the growth and acidogenicity of Streptococcus mutans  

Microsoft Academic Search

It is hypothesised that exogenous nitrite acidified by metabolic products of acidogenic bacteria in the mouth will be converted to products which inhibit growth of the bacteria in question which contribute to dental caries.Objectives. The aims of this study were (1) to test the activity of both sodium nitrate and sodium nitrite at differing concentrations on the ability of Streptococcus

Charlotte E. Radcliffe; Noreen C. Akram; Fiona Hurrell; David B. Drucker

2002-01-01

91

Serum nitrate and nitrite levels in patients with rheumatoid arthritis, ankylosing spondylitis, and osteoarthritis  

PubMed Central

Methods: Thirty five patients with RA, 32 patients with AS, and 36 patients with OA were entered into this study. In addition, 30 healthy volunteers acted as a control group. Concentrations of nitrate and nitrite in serum were determined by direct and indirect Griess reactions. C reactive protein and erythrocyte sedimentation rate levels were determined as markers of systemic activity of disease (SAD) in RA and AS groups. Results: Serum nitrate and nitrite levels were found to be higher in patients with AS and RA than in the OA group (p<0.01). In addition, serum nitrate and nitrite levels were higher in all three groups than in the control group (p<0.01). Moreover, serum nitrate and nitrite levels were higher in patients who had SAD than in those who had not in the RA and AS groups (p<0.01 and p<0.05, respectively), and there was a correlation between serum nitrate and nitrite concentrations and SAD variables in patients with RA (Spearman's rs=0.414, p<0.05 and rs=0.408, p<0.05, respectively) and AS (rs=0.421, p<0.05 and rs=0.412, p<0.05, respectively). Conclusion: The findings suggest that nitrate and nitrite production is enhanced in patients with inflammatory arthritis compared with OA. In addition, serum nitrate and nitrite levels are enhanced in patients with RA, AS, and OA compared with healthy subjects. Furthermore, there is a correlation between the SAD variables and serum nitrate and nitrite levels in patients with RA and AS.

Ersoy, Y; Ozerol, E; Baysal, O; Temel, I; MacWalter, R; Meral, U; Altay, Z

2002-01-01

92

Control of microbial souring by nitrate, nitrite or glutaraldehyde injection in a sandstone column  

Microsoft Academic Search

Microbial souring (production of hydrogen sulfide by sulfate-reducing bacteria, SRB) in crushed Berea sandstone columns with oil field-produced water consortia incubated at 60°C was inhibited by the addition of nitrate (NO3) or nitrite (NO2-). Added nitrate (as nitrogen) at a concentration of 0.71 mM resulted in the production of 0.57–0.71 mM nitrite by the native microbial population present during souring

M A Reinsel; J T Sears; P S Stewart; M J McInerney

1996-01-01

93

Automated simultaneous monitoring of nitrate and nitrite in surface water by sequential injection analysis  

Microsoft Academic Search

A fully automated procedure based on Sequential Injection Analysis (SIA) methodology for simultaneous monitoring of nitrate and nitrite in surface water samples is described. Nitrite was determined directly using the Griess diazo-coupling reaction and the formed azo dye was measured at 540nm in the flow cell of the fibre-optic spectrophotometer. Nitrate zone was passed through a reducing mini-column containing copperised-cadmium.

Zlatuše Legnerová; Petr Solich; Hana Sklená?ová; Dalibor Šat??nský; Rolf Karl???ek

2002-01-01

94

Genetic variation in the activity of nitrate reductase and nitrite reductase in Lolium  

Microsoft Academic Search

Summary Leaves from a half diallel cross between three populations ofL. perenne and three ofL. multiflorum were analysed for activity of nitrate reductase and nitrite reductase. Nitrate reductase activity was greater inL. perenne than inL. multiflorum and this correlated with variation in nitrate concentration in the plant. Nitrate reductase activity was significantly heritable at high nitrogen supply, but not at

P. J. Goodman; D. M. Hughes; M. Fothergill; P. B. Ellis

1974-01-01

95

Analysis of plasma nitrite/nitrate in human thermal injury.  

PubMed

The aim of this study is to examine the characteristics of nitrite/nitrate (NOx), the final metabolite of nitric oxides, in plasma after burn injury. A total of 83 blood samples were collected from 19 patients on arrival, day 1, day 3, and day 5 after suffering burn injuries and from 7 non-burned volunteers. We measured the NOx levels in plasma using the Griess method, and analyzed the relationships among plasma the NOx levels, the burn-magnitude, and the blood examination data using a stepwise multivariate regression analysis. The plasma NOx levels at hospital-arrival after burns significantly exceeded those of non-burned volunteers, and the NOx levels in the plasma returned to normal range after day 1. Based on the findings of a multivariate analysis, the plasma NOx levels at admission to the hospital were not found to be related to the total burn surface area, the burn index or inhalation injury, but they were significantly related to age. Furthermore, these plasma NOx levels were also related to the platelet count, neutrophil count and blood urea nitrogen. The increase in the plasma NOx level may therefore play an important role in the pathophysiology of elderly burned patients, while the nitric oxide levels in the plasma might also play a role in inhibiting the constriction of microvascular smooth muscle in extensively burned patients. PMID:11642340

Saitoh, D; Takasu, A; Fukuzuka, K; Norio, H; Sakamoto, T; Okada, Y

2001-06-01

96

Sonochemical formation of nitrate and nitrite in water  

PubMed

The formation of nitrite and nitrate ions in water under irradiation with 900 kHz ultrasound was studied as a function of time, temperature and gas (oxygen/nitrogen) composition. The rate decreases as temperature increases, and is below the detection limit when there is no O2 gas present. The absolute rate of formation of NOx- ions obtained (about 30 x 10(-9) mol min-1 W-1) agrees well with previous similar studies. The differences in the NO2-/NO3- ratio found between various studies can be satisfactorily explained though a mechanism where HNO2 and HNO3 are formed in the gas phase of the imploding cavity, and then dissolve in the water and dissociate to ions. The NO2- species is initially substantially favoured, as considerably more NO is formed than NO2. Thermodynamic calculations indicate that at the 'hot spot' temperature of about 5000 K believed to be present, there would very large amounts of NO and OH radicals present, and at such high temperatures, thermodynamics would be a good approximation of the situation, since the rates of reactions would be very rapid. The reaction needs O2 in order to proceed to a significant degree; no NOx- was detected in the absence of oxygen gas. PMID:10909728

Supeno; Kruus

2000-07-01

97

Isolated and combined exposure to ammonia and nitrite in rainbow trout ( Oncorhynchus mykiss): effects on electrolyte status, blood respiratory properties and brain glutamine\\/glutamate concentrations  

Microsoft Academic Search

Rainbow trout (Oncorhynchus mykiss) were exposed for up to 4 days to 100, 300 and 500 ?M ammonia and 0, 300 and 600 ?M nitrite. Each ammonia concentration was combined with each nitrite concentration, giving a total of nine exposure groups. High mortality was observed in trout exposed to 500 ?M ammonia in combination with 600 ?M nitrite. Other exposure

Niels E Vedel; Bodil Korsgaard; Frank B Jensen

1998-01-01

98

EFFECT OF ENVIRONMENTAL AMMONIA AND NITRITE ON EARLY DEVELOPMENTAL STAGES OF FLORIDA POMPANO TRACHINOTUS CAROLINUS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Florida pompano Trachinotus carolinus are currently being evaluated as a potential candidate for mariculture in the US. Presently, only limited information exists with respect to this species’ tolerance to aquaculture toxicants such as ammonia and nitrite and no work to date regarding this topic ha...

99

Progress report on the evaluation of porous cathode for the electrochemical reduction of nitrates and nitrites in liquid wastes  

SciTech Connect

This report describes the experimental and modeling work performed to evaluate porous cathodes for the electrochemical reduction of nitrites in liquid wastes. The experiments were done using the MP{dagger} cell with two different porous cathodes: nickel foam and TySAR{trademark}SB{double_dagger}. The experimental results are compared with each other and to those obtained with a planar nickel cathode. The results show that the ammonia production reaction is the dominant cathodic reaction ({approximately}80% efficiency) for all three electrodes. The temperature range used in this study was 29-37 {circ}C while the catholyte feed was either 0.6M NaNO{sub 2} or 1.9M NaNO{sub 3}, both supported by a 1.33 M NaOH solution. All experiments used a constant current density of 0.25 A/cm{sup 2}. The experimental results suggest that the porous nickel electrode at lower temperatures ({approximately}31{circ}C) is the most efficient of the three electrodes for the reduction of nitrates and nitrites. The porous nickel electrode exhibited the highest conversion of nitrates and nitrites, and the lowest overpotential for a given current density. The partial current fractions at known catholyte concentrations were used to extract the exchange-current densities for the five cathodic reactions. Using these kinetic parameters, dynamic simulations of the four hour experiments were performed. Agreement was found between the model and experimental results for changes in the moles of the nitrate and nitrite and the cell overpotential with time. Future work will determine the effects of temperature and current densities on the exchange-current densities and reaction product distributions. The performance of other porous cathode materials (TySAR{trademark}EP{section}, TySAR{trademark}IM) will also be evaluated.

Hobbs, D.T. [Westinghouse Savannah River Co., Aiken, SC (United States); Jha, K.; Weidner, J.W.; White, R.E. [South Carolina Univ., Columbia, SC (United States). Dept. of Chemical Engineering

1995-12-27

100

Nitrifying microorganisms in fixed-bed biofilm reactors fed with different nitrite and ammonia concentrations.  

PubMed

Nitrifying bacteria and archaea were fed in fixed-bed biofilm reactors with different nitrite and ammonia concentrations in synthetic and real wastewater. During high nitrite concentrations (rho(NO(2)(-))=5-10mg/L), an increase in the abundance of Nitrobacter species was detected with fluorescence in situ hybridization (FISH), while Nitrospira species disappeared to a large extent. During high ammonia concentrations (rho(NH(4)(+))=60-80 mg/L), a slight increase in ammonia-oxidizing bacteria was obtained, while the abundance of archaebacteria remained unchanged. Lab-scale reactors showed a similar nitrifying microbial population as reactors fed with real wastewater. However, increased abundances of Nitrospira species as observed in wastewater reactors and in the wastewater trickling filters could not be found in the laboratory reactors. PMID:19910189

ter Haseborg, Eike; Zamora, Talia Mateu; Fröhlich, Jörn; Frimmel, Fritz H

2009-11-12

101

Inorganic nitrate supplementation lowers blood pressure in humans: role for nitrite-derived NO.  

PubMed

Ingestion of dietary (inorganic) nitrate elevates circulating and tissue levels of nitrite via bioconversion in the entero-salivary circulation. In addition, nitrite is a potent vasodilator in humans, an effect thought to underlie the blood pressure-lowering effects of dietary nitrate (in the form of beetroot juice) ingestion. Whether inorganic nitrate underlies these effects and whether the effects of either naturally occurring dietary nitrate or inorganic nitrate supplementation are dose dependent remain uncertain. Using a randomized crossover study design, we show that nitrate supplementation (KNO(3) capsules: 4 versus 12 mmol [n=6] or 24 mmol of KNO(3) (1488 mg of nitrate) versus 24 mmol of KCl [n=20]) or vegetable intake (250 mL of beetroot juice [5.5 mmol nitrate] versus 250 mL of water [n=9]) causes dose-dependent elevation in plasma nitrite concentration and elevation of cGMP concentration with a consequent decrease in blood pressure in healthy volunteers. In addition, post hoc analysis demonstrates a sex difference in sensitivity to nitrate supplementation dependent on resting baseline blood pressure and plasma nitrite concentration, whereby blood pressure is decreased in male volunteers, with higher baseline blood pressure and lower plasma nitrite concentration but not in female volunteers. Our findings demonstrate dose-dependent decreases in blood pressure and vasoprotection after inorganic nitrate ingestion in the form of either supplementation or by dietary elevation. In addition, our post hoc analyses intimate sex differences in nitrate processing involving the entero-salivary circulation that are likely to be major contributing factors to the lower blood pressures and the vasoprotective phenotype of premenopausal women. PMID:20585108

Kapil, Vikas; Milsom, Alexandra B; Okorie, Michael; Maleki-Toyserkani, Sheiva; Akram, Farihah; Rehman, Farkhanda; Arghandawi, Shah; Pearl, Vanessa; Benjamin, Nigel; Loukogeorgakis, Stavros; Macallister, Raymond; Hobbs, Adrian J; Webb, Andrew J; Ahluwalia, Amrita

2010-06-28

102

Quantitative analysis of nitrate and nitrite contents in vegetables commonly consumed in Delta State, Nigeria.  

PubMed

Plasma thiocyanate has been reported to be high among cassava-eating populations such as that in Nigeria because of the cyanide content of cassava. Thiocyanate, which is secreted into the stomach contents of animals, has been demonstrated to catalyse the formation of nitrosamines (potent carcinogens) in the stomach from secondary amines and nitrite. The main source of the nitrite precursor in this environment is vegetables, primarily eaten as the chief supplier of proteins. The present study attempts to analyse the levels of nitrate and nitrite in vegetables commonly grown and consumed in Delta State, Nigeria. The nitrate and nitrite contents in green vegetable (Amaranthus spp.), bitter leaf (Vernonia amygdalina), pumpkin (Telfaria occidentalis) and water leaf (Talinum triangulare) grown in different localities of the state were determined by standard analytical procedures. The results show that those vegetables grown in the industrialised urban centres of the state had higher nitrate (223 (SD 71) mg/kg dry weight; P<0.05) and nitrite (12.6 (SD 1.7) mg/kg dry weight; P>0.05) levels when compared with the same species (188 (SD 77) mg nitrate/kg dry weight and 10.9 (SD 1.1) mg nitrite/kg dry weight) cultivated in less industrialised suburbs. We conclude that frequent consumption of such vegetables whose nitrate and nitrite contents are high by cassava-eating individuals might put them at risk of developing stomach cancer and other possible results of nitrate and/or nitrite toxicity. In order to avoid an outbreak in our communities, appropriate agencies should monitor and regulate the release of chemicals into the environment. In the meantime, the cultivation and consumption of vegetables grown in industrialised areas of the state should be discouraged. PMID:17092380

Onyesom, I; Okoh, P N

2006-11-01

103

Decreased steroid hormone synthesis from inorganic nitrite and nitrate: studies in vitro and in vivo.  

PubMed

Nitrites and nitrates are consumed nonchalantly in diet. Organic nitrates are also used as vasodilators in angina pectoris, but the therapy is associated with tolerance whose mechanism remains elusive. Previously, we found inorganic nitrate inhibited steroidogenesis in vitro. Because adrenocorticoids regulate water and electrolyte metabolism, tolerance may ensue from steroid deficiency. We have studied the effects of nitrite and nitrate on in vitro synthesis and in vivo blood levels of steroid hormones. In vitro, nitrite was more potent than nitrate in inhibiting human chorionic gonadotropin (hCG)-stimulated androgen synthesis by Mouse Leydig Tumor cells. At concentrations above 42 mM, nitrite completely inhibited androgen synthesis, and, unlike nitrate, the inhibition was irreversible by increasing hCG concentration. The cAMP production remained intact but reduced with both ions. The nitric oxide (NO) scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide (c-PTIO) significantly increased hCG- or cAMP-stimulated androgen synthesis in all buffers, suggesting that NO is a chemical species directly involved in the nitrite/nitrate-induced inhibition. This is further supported by c-PTIO countering the inhibitory action of methylene blue on androgen synthesis. Rats given distilled water containing 50 mg/L NaNO(2) or NaNO(3) for 4 weeks drank significantly less daily. At the end, their blood corticosterone and testosterone levels were significantly decreased. The adrenocortical histology showed bigger lipid droplets, which are pathogonomic of impaired steroidogenesis. Nitrite and nitrate are metabolized to NO, which binds heme in cytochrome P450 enzymes, thereby inhibiting steroidogenesis. Therapeutic nitrates likewise may decrease adrenal (and gonadal) steroidogenesis. Cortisol deficiency would impair water excretion causing volume expansion, and aldosterone deficiency would cause sodium loss and raised renin. Paradoxically, volume expansion without sodium retention and raised renin has all been reported in tolerance. PMID:11133344

Panesar, N S; Chan, K W

2000-12-15

104

Automatic System for Simultaneous Determination of Nitrates and Nitrites in Waters  

Microsoft Academic Search

An automatic FIA system for simultaneous determination of nitrates and nitrates in waters is described.The method is based on the classical azodye reaction for nitrites. The sample is split into two flows: (a) one is directly treated with the azodye reagent and sent to the sample flow cell of a double beam spectrophotometer, which gives positive absorbance values, allowing direct

J. Maimó; A. Cladera; F. Mas; R. Forteza; J. M. Estela; V. Cerdá

1989-01-01

105

Influence of sediment and pore-water composition on nitrite accumulation in a nitrate-perfused freshwater sediment  

Microsoft Academic Search

Anaerobic nitrate consumption was accompanied by the accumulation of nitrite in the range of 3–52?moll?1 in laboratory sediment cores continuously perfused with nitrate from below. Highest interstitial nitrite concentrations were observed in organically poor sediment cores with a low extractable protein content. Supplemented with an additional source of fixed nitrogen (ammonium), the nitrate-perfused sediments exhibited considerably lower nitrite concentrations than

Peter Stief

2001-01-01

106

Simultaneous determination of nitrite, nitrate and ascorbic acid in canned vegetable juices by reverse?phase ion?interaction HPLC  

Microsoft Academic Search

A simple ion?interaction C18 reverse?phase high performance liquid chromatographic method was developed for simultaneous determination of nitrite, nitrate and ascorbic acid in canned vegetable juices. The method makes use of 0.010 m octylammonium ortho?phosphate as the ion interacting reagent and 20% (v\\/v) aqueous methanol as the mobile phase. The content of nitrite, nitrate (expressed as nitrite ion and nitrate ion,

C. F. Cheng; C. W. Tsang

1998-01-01

107

Control of hydrogen sulfide production in oil fields by managing microbial communities through nitrate or nitrite addition  

Microsoft Academic Search

Nitrate or nitrite injection into oil reservoirs during water flooding has the potential to control biological souring, the production of hydrogen sulfide (H2S) by sulfate-reducing bacteria (SRB). Souring control is essential because sulfide is toxic, sulfide precipitates can plug reservoir formations, souring lowers crude oil value, and SRB induce corrosion. Nitrate and nitrite can stimulate heterotrophic nitrate- or nitrite-reducing bacteria

Casey R. J. Hubert

2004-01-01

108

A Novel Nitrate\\/Nitrite Permease in the Marine Cyanobacterium Synechococcus sp. Strain PCC 7002  

Microsoft Academic Search

The nrtP and narB genes, encoding nitrate\\/nitrite permease and nitrate reductase, respectively, were isolated from the marine cyanobacterium Synechococcus sp. strain PCC 7002 and characterized. NrtP is a member of the major facilitator superfamily and is unrelated to the ATP-binding cassette-type nitrate transporters that previously have been described for freshwater strains of cyanobacteria. However, NrtP is similar to the NRT2-

TOSHIO SAKAMOTO; KAORI INOUE-SAKAMOTO; DONALD A. BRYANT

1999-01-01

109

Use of Nitrates and Nitrites as Food Additives in Nordic Countries  

Microsoft Academic Search

An account is given of the presently permitted use of nitrates and nitrites as food additives in Denmark, Finland, Norway and Sweden. Nitrate is permitted to be added to milk for the production of solid, semisolid and mould cheeses at levels of 150-200 mg\\/l potassium nitrate. Due to the potential formation of especially nonvolatile N-nitroso compounds, attempts are made to

E. Poulsen

1980-01-01

110

Synthesis of LaMO 3 (M = Fe, Co, Ni) using nitrate or nitrite molten salts  

Microsoft Academic Search

Perovskite compound LaMO3 (M=Fe, Co, Ni) nanocrystals were successfully synthesized in molten nitrates or nitrites from a mixture of lanthanum nitrate and an M-containing nitrate for 2h. The effect of the various process parameters on the phase purity, crystallite size, specific surface area and morphology of the synthesized nanocrystals were systematically studied by XRD, scanning electron microscopy (SEM), simultaneous TG\\/DSC

Jun Yang; Runsheng Li; Junyi Zhou; Xiaoci Li; Yuanming Zhang; Yulin Long; Yongwang Li

2010-01-01

111

The Relationship between Gastric Juice Nitrate/Nitrite Concentrations and Gastric Mucosal Surface pH  

PubMed Central

Purpose To investigate gastric juice nitrate/nitrite concentration according to mucosal surface pH extent (area) of gastric corpus intimately contacting the gastric juice. Materials and Methods We included ninety-nine patients with dyspepsia. To evaluate gastric mucosal surface pH and its extent, gastric chromosocpy was performed by spraying phenol red dye on the corpus mucosa and estimating the extent of area with color changed. Nitrate/nitrite concentrations and pH of gastric juice were measured by ELISA and pH meter, respectively. Silver staining was done to histologically confirm the presence of Helicobacter pylori. Results Intragastric nitrate/nitrite concentrations in patients, showing phenol red staining mucosa were higher than those of unstaining mucosa (p=0.001): the more extensive in the area of phenol red staining area of corpus, the higher gastric juice pH found (r=0.692, p<0.001). Furthermore, the intragastric nitrate/nitrite concentrations correlated positively with gastric juice pH (r=0.481, p<0.001). Conclusion The changes of mucosal surface pH and its extent in gastric corpus might affect either pH or nitrate/nitrite level of gastric juice.

Lee, Hae Kyung; Kim, Hyunjung; Kim, Hyung-Keun; Cho, Young-Seok; Kim, Byung-Wook; Han, Sok-Won; Maeng, Lee So; Kim, Hee Na

2012-01-01

112

Reduction of Nitrite and Nitrate on Nano-dimensioned FeS  

NASA Astrophysics Data System (ADS)

The reaction of nitrite (NO2 -) and nitrate (NO3 -) on nanometer-sized FeS particles was investigated in alkaline (initial pH = 10.3) solutions at reaction temperatures of 22, 70, and 120 °C using in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and fluorescence spectroscopy that allowed an analysis of adsorbate complexation on the FeS and reaction product in the aqueous phase, respectively. ATR-FTIR showed that NO was a surface-bound intermediate on FeS during its exposure to NO2 - at all three reaction temperatures. Ammonia/ammonium (NH3/NH4 +) product was also produced when FeS was exposed to NO2 - at the 70 °C and 120 °C reaction temperatures. Activation of NO3 - to form surface-bound NO was experimentally observed to occur at 120 °C on FeS, but not at the lower reaction temperatures. Furthermore, NH3/NH4 + product in the aqueous phase was only present during the reaction of FeS with NO3 - at the highest temperature used in this study.

Gordon, Alexander D.; Smirnov, Alexander; Shumlas, Samantha L.; Singireddy, Soujanya; DeCesare, Matthew; Schoonen, Martin A. A.; Strongin, Daniel R.

2013-08-01

113

Acute blood pressure lowering, vasoprotective, and antiplatelet properties of dietary nitrate via bioconversion to nitrite.  

PubMed

Diets rich in fruits and vegetables reduce blood pressure (BP) and the risk of adverse cardiovascular events. However, the mechanisms of this effect have not been elucidated. Certain vegetables possess a high nitrate content, and we hypothesized that this might represent a source of vasoprotective nitric oxide via bioactivation. In healthy volunteers, approximately 3 hours after ingestion of a dietary nitrate load (beetroot juice 500 mL), BP was substantially reduced (Delta(max) -10.4/8 mm Hg); an effect that correlated with peak increases in plasma nitrite concentration. The dietary nitrate load also prevented endothelial dysfunction induced by an acute ischemic insult in the human forearm and significantly attenuated ex vivo platelet aggregation in response to collagen and ADP. Interruption of the enterosalivary conversion of nitrate to nitrite (facilitated by bacterial anaerobes situated on the surface of the tongue) prevented the rise in plasma nitrite, blocked the decrease in BP, and abolished the inhibitory effects on platelet aggregation, confirming that these vasoprotective effects were attributable to the activity of nitrite converted from the ingested nitrate. These findings suggest that dietary nitrate underlies the beneficial effects of a vegetable-rich diet and highlights the potential of a "natural" low cost approach for the treatment of cardiovascular disease. PMID:18250365

Webb, Andrew J; Patel, Nakul; Loukogeorgakis, Stavros; Okorie, Mike; Aboud, Zainab; Misra, Shivani; Rashid, Rahim; Miall, Philip; Deanfield, John; Benjamin, Nigel; MacAllister, Raymond; Hobbs, Adrian J; Ahluwalia, Amrita

2008-02-04

114

Mammalian synthesis of nitrite, nitrate, nitric oxide, and N-nitrosating agents  

Microsoft Academic Search

In recent years, a great deal of interest has been focused on exposure to nitrite (NO{sub 2⁻}) and nitrate (NO{sub 3⁻}), primarily because of the mounting evidence that N-nitrosamines can cause human cancer. Nitrite and NO{sub 3⁻} can participate in the endogenous formation of N-nitrosamines and, therefore, may play a critical role in the induction of cancer by this class

Marletta

2009-01-01

115

Simultaneous spectrophotometric determination of nitrite and nitrate by flow-injection analysis  

Microsoft Academic Search

An automatic direct spectrophotometric method for the simultaneous determination of nitrite and nitrate by flow-injection analysis has been developed. Nitrite reacts with 3-nitroaniline in the presence of hydrochloric acid (0.96–1.8 M HCl or pH 0.5–0.7) to form a diazonium cation, which is subsequently coupled with N-(1-naphthyl)-ethylenediamine dihydrochloride to form a stable purple azo dye, the absorbance of which is measured

M. J. Ahmed; C. D. Stalikas; S. M. Tzouwara-Karayanni; M. I. Karayannis

1996-01-01

116

Anaerobic respiration of Bacillus macerans with fumarate, TMAO, nitrate and nitrite and regulation of the pathways by oxygen and nitrate  

Microsoft Academic Search

In Bacillus macerans, anaerobic respiratory pathways and the regulation of facultatively anaerobic catabolism by electron acceptors were analysed. In addition to fermentative growth, B. macerans was able to grow anaerobically by fumarate, trimethylamine N-oxide, nitrate, and nitrite respiration with glycerol as donor. During growth by fumarate respiration, a membrane-bound fumarate reductase was present that was different from succinate dehydrogenase. The

Jan Schirawski; Gottfried Unden

1995-01-01

117

Acute toxicity and sublethal effects of ammonia and nitrite for juvenile cobia Rachycentron canadum  

Microsoft Academic Search

Nitrogenous compounds can be toxic to aquatic animals especially when they are reared at high stocking densities. Cobia (Rachycentron canadum) is a fast growing fish currently reared in cages, but with expanding production in intensive recirculating aquaculture systems (RAS). Therefore, the objective of this study was to evaluate the acute toxicity of ammonia and nitrite to juvenile cobia. Juveniles (1.74±0.11 g

Ricardo V. Rodrigues; Michael H. Schwarz; Brendan C. Delbos

2007-01-01

118

Modification of nitrifying biofilm into nitritating one by combination of increased free ammonia concentrations, lowered HRT and dissolved oxygen concentration  

Microsoft Academic Search

Nitrifying biomass on ring-shaped carriers was modified to nitritating one in a relatively short period of time (37 days) by limiting the air supply, changing the aeration regime, shortening the hydraulic retention time and increasing free ammonia (FA) concentration in the moving-bed biofilm reactor (MBBR). The most efficient strategy for the development and maintenance of nitritating biofilm was found to

Ivar Zekker; Ergo Rikmann; Toomas Tenno; Anne Menert; Vallo Lemmiksoo; Alar Saluste; Taavo Tenno; Martin Tomingas

2011-01-01

119

The reactivity of cesium nickel ferrocyanide towards nitrate and nitrite salts  

SciTech Connect

Beginning in late 1988, the Pacific Northwest Laboratory (PNL) began an experimental program at the request of Westinghouse Hanford Company (WHC) to investigate the effects of temperature on the oxidation reaction between synthetic nickel cesium ferrocyanide (FeCN) and nitrates and nitrites representative of materials present in some of the Hanford single-shell tanks (SSTs). After completing a preliminary series of experiments in 1988, the program was expanded to include five tasks to evaluate the effect of selected compositional and operational parameters on the reaction and explosion temperatures of FeCN and nitrate and/or nitrite mixtures. 10 refs., 4 figs., 6 tabs.

Burger, L.L.; Scheele, R.D.

1991-09-01

120

Nitrite and Nitrate in Ischemia-Reperfusion Injury  

Microsoft Academic Search

\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a There is a long and rich history of the use of nitrite for medical conditions.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Nitrite has a number of essential functions in mammalian tissues.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Nitrite is reduced to nitric oxide in blood and tissues, particularly in hypoxic or ischemic conditions.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Nitrite protects from ischemia-reperfusion injury due to modulation of mitochondrial respiration.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Nitrite has been

Madhav Lavu; Susheel Gundewar; David J. Lefer

121

Effect of high oral doses of nitrate on salivary recirculation of nitrates and nitrites and on bacterial diversity in the saliva of young pigs.  

PubMed

Ingested nitrate is absorbed in the small intestine, recirculated into the saliva and reduced to nitrite by oral bacteria. In pigs receiving a moderate dietary addition of nitrate, the recirculation into the saliva is modest, so we aimed to assess the effect of higher nitrate doses to find out how the animal reacts to this new situation and to evaluate if a higher nitrate level could enhance the nitrate reduction process, improving the nitrite production Trial 1. Six piglets received 100 g of a commercial diet with 2.45% KNO(3) . In relation to baseline values, nitrate in blood serum and saliva increased 15 times, and declined after 6 h vs. 2 h. Salivary nitrite increased seven times after the addition and declined after 6 h vs. 2 h. Trial 2. Six piglets were fed a diet with or without 1.22% KNO(3) for 2 weeks. Salivary nitrate and nitrite increased with the addition of KNO3: nitrate increased from d0 to the end of the trial, nitrite increased 15 times after 1 week, but decreased after 2 weeks to 4.5-fold the control. After 2 weeks, nitrate reduced Shan diversity index of salivary microbiota. The present results indicate that the long exposure to high quantities of nitrates impairs the oral reduction of nitrate to nitrite and engenders a reduction of the mouth's microbiota diversity. PMID:20796080

Trevisi, P; Casini, L; Nisi, I; Messori, S; Bosi, P

2010-08-27

122

Development of estimates of dietary nitrates, nitrites, and nitrosamines for use with the short willet food frequency questionnaire  

Microsoft Academic Search

BACKGROUND: Studies have suggested that nitrates, nitrites, and nitrosamines have an etiologic role in adverse pregnancy outcomes and chronic diseases such as cancer. Although an extensive body of literature exists on estimates of these compounds in foods, the extant data varies in quality, quantified estimates, and relevance. METHODS: We developed estimates of nitrates, nitrites, and nitrosamines for food items listed

John S Griesenbeck; Michelle D Steck; John C Huber Jr; Joseph R Sharkey; Antonio A Rene; Jean D Brender

2009-01-01

123

INFLUENCE OF DIFFERENT EXTRACTION CONDITIONS AND SAMPLE PRETREATMENTS ON QUANTIFICATION OF NITRATE AND NITRITE IN SPINACH AND LETTUCE  

Microsoft Academic Search

Different sample pretreatment and extraction techniques are often used for analysis of nitrates and nitrites, however, the effects of these variables have not been properly examined. Comparative investigations were carried out with the objective of finding the most suitable conditions for quantification of nitrate and nitrite in spinach and lettuce. A rapid and cost effective RP-HPLC\\/UV method was validated and

Edgar Pinto; Catarina Petisca; Luís F. Amaro; Olívia Pinho; Isabel M. P. L. V. O. Ferreira

2010-01-01

124

Effect of nitrate and nitrite curing salts on microbial changes and sensory quality of non-fermented sausages  

Microsoft Academic Search

The effects of nitrate and nitrite curing salts on microbial changes and sensory quality of non-fermented sausages of small diameter were investigated. During pre-ripening (day 5), levels of lactic acid bacteria and yeasts were slightly higher in nitrite-made sausages than in those made with nitrate. In contrast, nitrite discouraged the growth of psychrotrophs as occurs in fermented sausages. By the

Y Sanz; R Vila; F Toldrá; J Flores

1998-01-01

125

[Presence of nitrates and nitrites in baker's products and in certain other flour products].  

PubMed

The results of the study demonstrated that the content of nitrates and nitrites in various baker's products varied from 0.96 (in wheat rolls and baguettes) to 44.07 mg KO3/kg in pumpernickel bread. In wholemeal bread, village bread, tourist bread, rye brown bread and Graham bread the content of these compounds was from 1.46 to 27.10 mg KNO3/kg. The mean content of nitrites in these bread sorts was 1.76 mg NaNo2/kg, range 0.10-4.40 mg NaNo2/kg. In white wheat flours (Wroc?aw flour, cake flour and Pozna? flour) the content of nitrates ranged from 1.10 to 19.08 mg KNO3/kg, and in the dishes produced from them in household was from 0.50 to 16.33 mg KNO3/kg. The content of nitrites in these flours was in the range from 0.00 to 4.16 mg NaNo2/kg, and in the products prepared from them it was from 0.00 to 1.60 mg NaNO2/kg. Eleven types were tested also of popular biscuits, wafers, gingerbread and hard cakes in which the content of nitrates was from 3.66 to 17.72 mg/kg, and that of nitrites was from 0.00 to 8.80 mg NaNo2/kg. Considering the average consumption of these products per one person in the seashore region and the mean values of nitrates and nitrites it was calculated that they provided daily about 3.9 mg KNO3 and 0.4 NaNo2, that is about 1.8% of nitrates and 7.7% of nitrites consumed by adults in daily food ration. PMID:2267558

Nabrzyski, M; Gajewska, R; Ganowiak, Z

1990-01-01

126

[Nitrite and nitrate content of foods sampled during national food quality monitoring].  

PubMed

The aim of the french national inquiry of food quality is to ascertain the presence in food of many contaminants, in particular nitrates and nitrites. Because of variability of contamination in samples, a great number of determinations were carried out for each food kind (2296 determinations in 62 foods kinds). Nitrate amounts are in fact very high in beet roots, white beets, celery salads, radishes and green salads. PMID:7258921

Deschamps, P

1980-01-01

127

New Electrochemical Sensors for Nitrites and Nitrates Determination in Drinking Waters  

NASA Astrophysics Data System (ADS)

In this communication, we propose an electrochemical procedure based on the direct nitrite oxidation at different electrochemical sensors, consisting in Pt or carbon electrodes covered by permselective membranes: acetate cellulose membrane and non-conducting polymers electrosynthesised onto the electrode surface. The membranes permselectivity have been tested vs. the most common interferences. The best results were obtained with cellulose acetate and electropolymers synthesised starting from 1.2-DAB, 1.5-DAN and 1.8-DAN. These nitrite sensors have been fully characterised and incorporated in FIA system. Parameters as flow rate, injection volume have been optimised and the response vs. nitrite and possible interferents, present in drinking water, has been evaluated. A detection limit ranging from 1 to 0.1 mM for cellulose acetate membrane and for electrosynthesised polymers was calculated. Nitrites in water were determined by direct injection, without further pretreatment of the sample. The analysis of nitrate was carried out with the same procedure used for nitrites, the difference being the introduction of a cupperised cadmium reactor which reduces quantitatively nitrates to nitrites which was oxidised at the electrode.

Curulli, Antonella; Volpe, Giulia; Moscone, Danila; Palleschi, Giuseppe; Badea, Micaela; Amine, Aziz

2000-12-01

128

Cured meat products without direct addition of nitrate or nitrite: what are the issues?  

Microsoft Academic Search

The growing popularity of food products marketed in the United States as “natural” and “organic” has resulted in a proliferation of marketing efforts to meet consumer demands for these foods. Because natural and organic foods are not permitted to use chemical preservatives, the traditional curing agents used for cured meats, nitrate and\\/or nitrite, cannot be added to natural and organic

Joseph G. Sebranek; James N. Bacus

2007-01-01

129

Comparative ease of separation of mixtures of selected nuisance anions (nitrate, nitrite, sulfate, phosphate) using Octolig®  

Microsoft Academic Search

Mixtures of sodium salts of nitrate, nitrite, sulfate, and phosphate were prepared in relative amounts present in atomic waste containers with a view to effect removal by chromatography over Octolig®, commercially available material with polyethylenediamine moieties covalently attached to high-surface area silica gel. Separation was attempted using aqueous solutions and column chromatography with Octolig®. It is presumed that this material

Frederick W. Stull; Dean F. Martin

2009-01-01

130

Electrochemical reduction of nitrates and nitrites in alkaline nuclear waste solutions  

Microsoft Academic Search

Sodium nitrate and nitrite are major components of alkaline nuclear waste streams and contribute to environmental release hazards. The electrochemical reduction of these materials to gaseous products has been studied in a synthetic waste mixture. The effects of electrode materials, cell design, and other experimental parameters have been investigated. Lead was found to be the best cathode material in terms

J. D. Genders; D. Hartsough; D. T. Hobbs

1996-01-01

131

Anammox bacteria disguised as denitrifiers: nitrate reduction to dinitrogen gas via nitrite and ammonium.  

PubMed

Anaerobic ammonium-oxidizing (anammox) bacteria oxidize ammonium with nitrite and produce N(2). They reside in many natural ecosystems and contribute significantly to the cycling of marine nitrogen. Anammox bacteria generally live under ammonium limitation, and it was assumed that in nature anammox bacteria depend on other biochemical processes for ammonium. In this study we investigated the possibility of dissimilatory nitrate reduction to ammonium by anammox bacteria. Physically purified Kuenenia stuttgartiensis cells reduced (15)NO(3) (-) to (15)NH(4) (+) via (15)NO(2) (-) as the intermediate. This was followed by the anaerobic oxidation of the produced ammonium and nitrite. The overall end-product of this metabolism of anammox bacteria was (15)N(15)N dinitrogen gas. The nitrate reduction to nitrite proceeds at a rate of 0.3 +/- 0.02 fmol cell(-1) day(-1) (10% of the 'normal' anammox rate). A calcium-dependent cytochrome c protein with a high (305 mumol min(-1) mg protein(-1)) rate of nitrite reduction to ammonium was partially purified. We present evidence that dissimilatory nitrate reduction to ammonium occurs in Benguela upwelling system at the same site where anammox bacteria were previously detected. This indicates that anammox bacteria could be mediating dissimilatory nitrate reduction to ammonium in natural ecosystems. PMID:17298364

Kartal, Boran; Kuypers, Marcel M M; Lavik, Gaute; Schalk, Jos; Op den Camp, Huub J M; Jetten, Mike S M; Strous, Marc

2007-03-01

132

Some microbiological, chemical analysis and nitrate nitrite levels of drinking and well water samples in Afyonkarahisar  

Microsoft Academic Search

Summary: A total of 100 tap and 100 well water samples were collected from six municipalities and the city center in Afyonkarahisar region from January 2003 to December 2003 and analyzed for some microbiological, chemical parameters and nitrate nitrite levels. While total (TCC) and fecal (thermotolerant) coliforms (FCC), Escherichia coli isolation procedure were determined using multiple-tube fermentation technique, sulphide reducing

Belgin SIRIKEN; Hidayet YAVUZ

133

Glycine propionyl-L-carnitine increases plasma nitrate\\/nitrite in resistance trained men  

Microsoft Academic Search

: We have recently demonstrated that oral intake of glycine propionyl-L-carnitine (GPLC) increases plasma nitrate\\/nitrite (NOx), a surrogate measure of nitric oxide production. However, these findings were observed at rest, and in previously sedentary subjects. PURPOSE: In the present study, we sought to determine the impact of oral GPLC on plasma NOx at rest and in response to a period

Richard J Bloomer; Webb A Smith; Kelsey H Fisher-Wellman

2007-01-01

134

Application of capillary electrophoresis in anion binding studies: Complexation and separation of nitrate and nitrite by an azacryptand  

PubMed Central

Capillary electrophoresis (CE) was employed for studying the complexation of an azacryptand with nitrate and nitrite in aqueous solution. CE separation of a mixture of nitrate and nitrite with 10 mM acetate buffer (pH 3.3) showed two peaks at the retention times of 2.8 and 3.1 min for nitrate and nitrite, respectively. However, when the ligand (2 mM) was added to the running buffer, the peaks emerged in the reverse order and at shorter retention times of 2.7 and 2.5 min for nitrate and nitrite, respectively. The longer retention time for nitrate compared with nitrite indicates a stronger complex formation between the ligand and nitrate, that reduces the migration speed of nitrate as compared with the less strongly bound nitrite. The 1H NMR titrations of L with these two anions at the pH 3.3, gave the binding constants (log K), 3.75 and 4.23, for nitrite and nitrate, respectively which were in consistence with the results obtained from the CE method.

Wu, Hao; Saeed, Musabbir A.; Hwang, Huey-Min; Zhao, Shulin; Liu, Yi-Ming; Hossain, Md. Alamgir

2010-01-01

135

The Effect of Carbon Dioxide Concentration and Buffer System on Nitrate and Nitrite Assimilation by Dunaliella tertiolecta  

Microsoft Academic Search

SUMMARY Dunaliella tertiolecta required carbon dioxide in substrate concentrations (1.75 %, v\\/v) to assimilate either nitrate or nitrite at maximum rates in light. The addition of glucose, glycerol, acetate, pyruvate or a-ketoglutarate did not remove the requirement for carbon dioxide. The rates of nitrate and nitrite assimilation in light depended upon the buffer system used. The lowest rates of nitrate

B. R. GRANT

1968-01-01

136

Macrophage synthesis of nitrite, nitrate, and N-nitrosamines: precursors and role of the respiratory burst  

SciTech Connect

The macrophage cell line RAW 264.7 when activated with Escherichia coli lipopolysaccharide and interferon-..gamma.. synthesized nitrite (NO/sub 2//sup -/) and nitrate (NO/sub 3//sup -/). Medium change after the activation showed that L-arginine was the only amino acid essential for this synthesis. D-Arginine would not substitute for L-arginine. Other analogues that could replace L-arginine were L-homoarginine, L-arginine methyl ester, L-arginamide, and the peptide L-arginyl-L-aspartate. L-Argininic acid, L-agmatine, L-ornithine, urea, L-citrulline, and ammonia were among the nonprecursors, while L-canavanine inhibited this L-arginine-derived NO/sub 2//sup -//NO/sub 3//sup -/ synthesis. When morpholine was added to the culture medium of the activated RAW 264.7 macrophages, N-nitrosation took place, generating N-nitrosomorpholine. GC/MS experiments using L-(guanido-/sup 15/N/sub 2/)arginine established that the NO/sub 2//sup -//NO/sub 3//sup -/ and the nitrosyl group of N-nitrosomorpholine were derived exclusively from one or both of the terminal guanido nitrogens of arginine. Chromatographic analysis showed that the other product of the L-arginine synthesis of NO/sub 2//sup -//NO/sub 3//sup -/ was L-citrulline. The role of the respiratory burst in NO/sub 2//sup -//NO/sub 3//sup -/ synthesis was examined using the macrophage cell lines J774.16 and J774 C3C. Both cell lines synthesized similar amounts of NO/sub 2//sup -//NO/sub 3//sup -/. However, J774 C3C cells do not produce superoxide and hence do not exhibit the respiratory burst. Additional experiments also ruled out the involvement of the respiratory burst in NO/sub 2//sup -//NO/sub 3//sup -/ synthesis.

Iyengar, R.; Stuehr, D.J.; Marletta, M.A.

1987-09-01

137

[The content of nitrates and nitrites in fruits, vegetables and other foodstuffs].  

PubMed

There are presented the results of the investigation of many popular fresh and frozen vegetables as well as in fresh and frozen fruits, such as different kind of apples, strawberries, currants, raspberries and many other tender fruits mainly from market and few from own allotment-cottages performed in the year 1989-1992. The nitrate and nitrite was determined according to the Griess reaction. High levels of nitrate was encountered in lettuce, frozen spinach, fennel, radishes, parsley. Many of this samples contained more than 1000 mg of KNO3/kg of fresh product, but the highest level, over the 3500 mg/kg was found in lettuce. The remaining vegetables like carrots, celery, leeks and frozen French bean contained from several dozen to more than 800 mg KNO3/kg. The level of nitrite in all samples of the investigated vegetables and fruits was very low from zero to decimal part of milligram per kg. Very low level of nitrate was found in 7 species of investigated apples (from 1.3 to 9.7 mg KNO3/kg). A little higher level of this compound was ascertained in currants, gooseberries, raspberries, cherries (from 0.0 to 36.0 mg KNO3/kg product). The highest levels of nitrate occurred in samples of strawberries (maximum to 322.3 mg KNO3/kg) but mean level amounted 58.7 mg KNO3/kg. The encountered levels of nitrate in frozen vegetables and fruits as well as in jams and stewed fruits was only little less than in fresh products. Very high level (from 355.30 to 584.53 mg KNO3/kg) was ascertained in the fruit-vegetable juice named "Rinberen" and "Malberen" to which red beet extract was used for their production. It should be pointed out that when the containers of these juice was opened and stored at the room temperature (+20 degrees C) during 30 days, no changes was observed in the level of nitrate and nitrite. In the juice prepared from blanched carrot, the rate of the reduction of nitrate to nitrite has not been lowered, when this product was storage of this juice at room temperature, the mean level of nitrite increased significantly (from 0.14 to 82.89 mg NaNO2/kg) and the level of nitrate lowered from 261.0 to 46.4 mg KNO3/kg. It should be strongly recommended for consumption the juices from carrot only fresh prepared. There are also presented the results of investigation of nitrate in fermented cheeses.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7777773

Nabrzyski, M; Gajewska, R

1994-01-01

138

[Content of nitrates and nitrites in early vegetables and potatoes sold in the marketplace of Bia?ystok in the year 1992].  

PubMed

Nitrate and nitrite were determined in early vegetables and potatoes sold in Bia?ystok in 1992. The levels of nitrates and nitrites were determined in 248 samples. Nitrate and nitrite were evaluated spectrophotometrically by the method of the Griess reaction, after reduction of the nitrates to nitrites, with cadmium dust. High values of nitrate were found in the early vegetables: lettuce, young red beets, radishes, dills, parsley, carrots, cucumbers and potatoes. The results were higher than the suggested limit in Poland. The nitrite contents, except for carrots, were determined in selected vegetables and potatoes. PMID:7878349

Rostkowski, J; Borawska, M; Omieljaniuk, N; Ot?og, K

1994-01-01

139

Physiological characterization of a plastidic signal required for nitrate-induced appearance of nitrate and nitrite reductases  

Microsoft Academic Search

We compared the response of NO3--induced nitrate-reductase (NR) and nitrite-reductase (NIR) levels in virtually carotenoid-free far-red-light-grown mustard (Sinapis alba L.) cotyledons following a photooxidative treatment of the plastids. The cytosolic localization of NR and the plastidic localization of NIR were confirmed with this approach. Emphasis was on a plastidic factor previously postulated to be involved obligatorily in the transcriptional control

R. Oelmiiller; C. Schuster; H. Mohr

1988-01-01

140

Effect of betaine supplementation on plasma nitrate/nitrite in exercise-trained men  

PubMed Central

Background Betaine, beetroot juice, and supplemental nitrate have recently been reported to improve certain aspects of exercise performance, which may be mechanistically linked to increased nitric oxide. The purpose of the present study was to investigate the effect of betaine supplementation on plasma nitrate/nitrite, a surrogate marker or nitric oxide, in exercise-trained men. Methods We used three different study designs (acute intake of betaine at 1.25 and 5.00 grams, chronic intake of betaine at 2.5 grams per day for 14 days, and chronic [6 grams of betaine per day for 7 days] followed by acute intake [6 grams]), all involving exercise-trained men, to investigate the effects of orally ingested betaine on plasma nitrate/nitrite. Blood samples were collected before and at 30, 60, 90, and 120 min after ingestion of 1.25 and 5.00 grams of betaine (Study 1); before and after 14 days of betaine supplementation at a dosage of 2.5 grams (Study 2); and before and after 7 days of betaine supplementation at a dosage of 6 grams, followed by acute ingestion of 6 grams and blood measures at 30 and 60 min post ingestion (Study 3). Results In Study 1, nitrate/nitrite was relatively unaffected and no statistically significant interaction (p = 0.99), dosage (p = 0.69), or time (p = 0.91) effects were noted. Similar findings were noted in Study 2, with no statistically significant interaction (p = 0.57), condition (p = 0.98), or pre/post intervention (p = 0.17) effects noted for nitrate/nitrite. In Study 3, no statistically significant changes were noted in nitrate/nitrite between collection times (p = 0.97). Conclusion Our data indicate that acute or chronic ingestion of betaine by healthy, exercise-trained men does not impact plasma nitrate/nitrite. These findings suggest that other mechanisms aside from increasing circulating nitric oxide are likely responsible for any performance enhancing effect of betaine supplementation.

2011-01-01

141

The Nitrate–Nitrite–Nitric Oxide Pathway in Traditional Herbal Medicine for Heart Disease  

Microsoft Academic Search

\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a The inorganic anions nitrate and nitrite are important intermediates in the nitrogen cycle.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a The nitrate–nitrite–nitric oxide pathway has been shown to exist in many alternative herbal medicines or dietary supplements.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a Many herbal medicines contain high levels of nitrate and to a less extent nitrite.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a \\u000a There is an effective system in certain herbal medicines for reducing nitrite

Yong-Jian Geng

142

Removal of nitrite with sulfamic acid for nitrate N and O isotope analysis with the denitrifier method.  

PubMed

In environmental water samples that contain both nitrate (NO3-) and nitrite (NO2-), isotopic analysis of nitrate alone by all currently available methods requires pretreatment to remove nitrite. Sulfamic acid addition, used previously for this purpose (Wu JP, Calvert SE, Wong CS. Deep-Sea Research Part I - Oceanographic Research Papers 1997; 44: 287), is shown here to be compatible with the denitrifier method for both N and O isotope analysis of nitrate. Sulfamic acid at a pH of approximately 1.7 reduces nitrite to N2. Samples are then neutralized with base prior to isotope analysis, to alleviate the buffering demands of the bacterial media and as a precaution to prevent modification of nitrate during storage with the residual sulfamic acid at low pH. Under appropriate reaction conditions, nitrite is completely removed within minutes. Sulfamic acid treatment does not compromise the completeness of the conversion of nitrate into N2O or the precision and accuracy of N and O isotope measurements by the denitrifier method. Nitrite concentrations upwards of 7 times the ambient nitrate can be removed without affecting the isotope composition of nitrate. The method is applied to analyses of the coupled N and O isotopes of nitrate and nitrite in waters of the Mexican Margin, to illustrate its efficacy and utility when employed either in the field upon sample collection or in the lab after months of frozen sample storage. PMID:19908214

Granger, Julie; Sigman, Daniel M

2009-12-01

143

Coaction of light, nitrate and a plastidic factor in controlling nitrite-reductase gene expression in spinach  

Microsoft Academic Search

It is well established that nitrite reductase (NIR; EC 1.7.7.1) a key enzyme of nitrate reduction — is “induced” by nitrate and light. In the present study with the spinach (Spinacia oleracea L.) seedling the dependency of NIR appearance on nitrate, light and a ‘plastidic factor’ was investigated to establish the nature of the coaction between these controlling factors. A

B. Seith; C. Schuster; H. Mohr

1991-01-01

144

Modeling pitting corrosion of iron exposed to alkaline solutions containing nitrate and nitrite  

NASA Astrophysics Data System (ADS)

Pitting corrosion could be extremely serious for dilute high-level radioactive waste stored or processed in carbon steel tanks at the Savannah River Site. In these solutions, nitrate is an aggressive ion with respect to pitting of carbon steel while nitrite can be used as an inhibitor. Excessive additions of nitrite increase the risk of generating unstable nitrogen compounds during waste processing, and insufficient additions of nitrite could increase the risk of corrosion-induced failure. Thus there are strong incentives to obtain a fundamental understanding of the role of nitrite in pitting corrosion prevention with these solution chemistries. In this dissertation, both a 1-D and a 2-D model are used to study the pitting mechanism as a function of nitrite/nitrate ratios. The 1-D model used BAND(J) to test a reaction mechanism for the passivation behavior by comparing the predicted Open Circuit Potential (OCP) with OCP data from experiments at different NO2-/NO3- ratio. The model predictions are compared with Cyclic Potentiodynamic Polarization (CPP) experiments. A 2-D model was developed for the propagation of a pit in iron by writing subroutines for finite element software of GAMBIT and FIDAP. Geometrically distributed anodic and cathodic reactions are assumed. The results show three partial explanations describing the inhibition influence of nitrite to iron corrosion: the competing reduction reaction of nitrate to nitrite, the formation of Fe(OH)+, and the function of the porous film. The current distributions and the effect of porosity of the film on pH are also explained. The calculation results also show that rate of pit growth decreases as the pit diameter increases until it reaches a constant value. The profile of the local current density on the pit wall is parabolic for small pits and it changes to a linear distribution for large pits. The model predicts that addition of nitrite will decrease the production of ferrous ions and those can prevent iron from dissolving. Also nitrate ion will accumulate in the pit if not enough inhibitor is added to the solution, and this will accelerate pit growth.

Chen, Lifeng

2001-07-01

145

Bioelectrode-based approach for enhancing nitrate and nitrite removal and electricity generation from eutrophic lakes.  

PubMed

Nitrate and nitrite contamination of surface waters (e.g. lakes) has become a severe environmental and health problem, especially in developing countries. The recent demonstration of nitrate reduction at the cathode of microbial fuel cell (MFC) provides an opportunity to develop a new technology for nitrogen removal from surface waters. In this study, a sediment-type MFC based on two pieces of bioelectrodes was employed as a novel in situ applicable approach for nitrogen removal, as well as electricity production from eutrophic lakes. Maximum power density of 42 and 36 mW/m(2) was produced respectively from nitrate- and nitrite-rich synthetic lake waters at initial concentration of 10 mg-N/L. Along with the electricity production a total nitrogen removal of 62% and 77% was accomplished, for nitrate and nitrite, respectively. The nitrogen removal was almost 4 times higher under close-circuit condition with biocathode, compared to either the open-circuit operation or with abiotic cathode. The mass balance on nitrogen indicates that most of the removed nitrate and nitrite (84.7 ± 0.1% and 81.8 ± 0.1%, respectively) was reduced to nitrogen gas. The nitrogen removal and power generation was limited by the dissolved oxygen (DO) level in the water and acetate level injected to the sediment. Excessive oxygen resulted in dramatically decrease of nitrogen removal efficiency and only 7.8% removal was obtained at DO level of 7.8 mg/l. The power generation and nitrogen removal increased with acetate level and was nearly saturated at 0.84 mg/g-sediment. This bioelectrode-based in situ approach is attractive not only due to the electricity production, but also due to no need of extra reactor construction, which may broaden the application possibilities of sediment MFC technology. PMID:23034447

Zhang, Yifeng; Angelidaki, Irini

2012-09-16

146

Influence of free ammonia on completely autotrophic nitrogen removal over nitrite (CANON) process.  

PubMed

Free ammonia (FA) plays a significant role in the stable, long-term, completely autotrophic nitrogen removal over nitrite (CANON) system operation. The influence of FA on the CANON process in a sequencing batch biofilm reactor was explored. Under controlled FA concentrations of 5.0 mg L(-1) to 10.0 mg L(-1), nitrite-oxidizing bacteria (NOB) was inhibited and achieved partial nitrification, which was important for a successful and quick start-up of the CANON process from activated sludge. However, NOB was acclimated to the condition after the process start-up. Ammonia-oxidizing bacteria (AOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) activities were unaffected when FA concentration was increased from 10 mg L(-1) to 17 mg L(-1), but NOB was completely inhibited only for a short time. The AOB and AnAOB activities were inhibited and the CANON system was deteriorated when FA concentration reached 30 mg L(-1) to 32.5 mg L(-1) at pH 8.5, whereas NOB activity was unaffected. Correlation analysis showed that FA concentration higher than 20 mg L(-1) resulted in the deterioration of the system. PMID:22588737

Li, Shan; Chen, You-Peng; Li, Chun; Guo, Jin-Song; Fang, Fang; Gao, Xu

2012-05-16

147

Effect of nitrate and nitrite curing salts on microbial changes and sensory quality of rapid ripened sausages  

Microsoft Academic Search

The effect of the use of either nitrite or nitrate curing salts on microbial changes and sensory quality in rapid ripened sausages inoculated with a mixed starter culture (Lactobacillus sake and Staphylococcus carnosus) was investigated. Lactic acid bacteria and Micrococcaceae were not greatly affected by the added curing salt. Conversely, the inhibition exerted by nitrite on the undesirable flora (Enterobacteriaceae

Y. Sanz; R. Vila; F. Toldrá; P. Nieto; J. Flores

1997-01-01

148

Ammonia\\/lithium nitrate absorption\\/compression refrigeration cycle. Part I. Simulation  

Microsoft Academic Search

Ammonia\\/lithium nitrate absorption refrigeration combined with mechanical vapour compression in the same circuit permits higher efficiencies than individual compression or absorption cycles. The absorption cycle produces pure ammonia refrigerant and is thus suitable for retrofitting projects in existing ammonia mechanical vapour compression plants. The cycle is modelled over a range of proportions from 0 to 100% mechanical vapour compression. Different

R. Ayala; C. L. Heard; F. A. Holland

1997-01-01

149

Risk of non-Hodgkin lymphoma and nitrate and nitrite from the diet in Connecticut women  

Microsoft Academic Search

It has been estimated that 65,980 individuals were diagnosed with non-Hodgkin lymphoma (NHL) and 19,500 died from NHL in the\\u000a United States in 2009. Although established risk factors such as immunodeficiency and viral infections may be responsible\\u000a for a portion of the cases, the majority of NHL cases remain unexplained. Dietary nitrate and nitrite intake are exposures\\u000a of particular interest

Briseis A. Kilfoy; Mary H. Ward; Tongzhang Zheng; Theodore R. Holford; Peter Boyle; Ping Zhao; Min Dai; Brian Leaderer; Yawei Zhang

2010-01-01

150

The determination of nitrite and nitrate in foods by capillary ion electrophoresis  

Microsoft Academic Search

Capillary ion electrophoresis (CIE) has been used to determine the nitrite and nitrate content of a range of foods. The samples tested were cheese, cabbage puree, fruit juice, water and a variety of meat products. A 75 cm × 75 ?m i.d. fused silica capillary column was used, with a simple OFM Anion-BT\\/sodium chloride electrolyte. The operating voltage was ?20kV,

Philip A. Marshall; V. Craige Trenerry

1996-01-01

151

Intake of nitrate and nitrite and the risk of gastric cancer: a prospective cohort study  

Microsoft Academic Search

The association between the intake of nitrate or nitrite and gastric cancer risk was investigated in a prospective cohort study started in 1986 in the Netherlands, of 120,852 men and women aged 55-69 years. At baseline, data on dietary intake, smoking habits and other covariates were collected by means of a self-administered questionnaire. For data analysis, a case-cohort approach was

AJM van Loon; A. A. M. Botterweck; R. A. Goldbohm; HAM Brants; JD van Klaveren; PA van den Brandt

1998-01-01

152

Dielectric and electrical conductivity studies in potassium nitrite and potassium nitrate  

Microsoft Academic Search

The dc conductivity, the dielectric constant and the dielectric loss at 100 kHz and 3·6 GHz, have been measured for samples of potassium nitrite and potassium nitrate over a wide range of temperature. The dc conductivity and the dielectric constant show anomalies at ?13°C and 40°C in a crystal of KNO2 pulled from the melt. However, the dielectric anomaly at

A. Mansingh; A. M. Smith

1971-01-01

153

DXRD studies of sodium nickel ferrocyanide reactions with equimolar nitrate\\/nitrite salts  

Microsoft Academic Search

Dynamic X-ray diffraction (DXRD) has been used to identify and quantify the solid-state reactions that take place between sodium nickel ferrocyanide, Na[sub 2]NiFe(CN)[sub 6], and equimolar concentrations of sodium nitrate\\/nitrite, reactions of interest to the continued environmental safety of certain waste storage tanks at the Hanford site in eastern Washington. The results are supportive of previous work that indicated that

Joseph N. Dodds; William J. Thomson

1994-01-01

154

Nitric Oxide and Exhaled Breath Nitrite\\/Nitrates in Chronic Obstructive Pulmonary Disease Patients  

Microsoft Academic Search

Background: Measurement of nitric oxide (NO) and nitrite\\/nitrates (NOx) levels in exhaled breath condensate (EBC) are non-invasive techniques, which can be used to monitor airway inflammatory diseases. Production of NO is often increased in inflammatory diseases of the airways, including exacerbations of chronic obstructive pulmonary disease (COPD). COPD-associated airway inflammation may be affected by multiple factors, including cigarette smoking and

Jia Liu; Alessandra Sandrini; Michelle C. Thurston; Deborah H. Yates; Paul S. Thomas

2007-01-01

155

Nitrite and nitrate ions as infrared pressure gauges for diamond anvils  

Microsoft Academic Search

The infrared spectra of the antisymmetric stretching bands of dilute solutions of nitrite and nitrate ions in sodium bromide are proposed as pressure gauges for use with anvils and other apparatuses. Their frequencies, which are at 1279.0 and 1401.3 cm?1 respectively at zero pressure, were measured up to 186 kbar relative to the R1 fluorescence line of ruby. The pressure

D. D. Klug; E. Whalley

1983-01-01

156

Corrosion risk associated with microbial souring control using nitrate or nitrite  

Microsoft Academic Search

Souring, the production of hydrogen sulfide by sulfate-reducing bacteria (SRB) in oil reservoirs, can be controlled through nitrate or nitrite addition. To assess the effects of this containment approach on corrosion, metal coupons were installed in up-flow packed-bed bioreactors fed with medium containing 8 mM sulfate and 25 mM lactate. Following inoculation with produced water to establish biogenic H2S production, some bioreactors

Casey Hubert; Mehdi Nemati; Gary Jenneman; Gerrit Voordouw

2005-01-01

157

Circulating and excretory nitrite and nitrate as indicators of nitric oxide synthesis in humans: methods of analysis  

Microsoft Academic Search

Nitric oxide (NO) is produced in various cells from l-arginine by the catalytical action of NO synthases (NOS). The main metabolic fate of NO includes oxidation to nitrate by\\u000a oxyhemoglobin in red blood cells and autoxidation to nitrite. Nitrate and nitrite circulate in blood and are excreted in urine.\\u000a The concentration of these NO metabolites in plasma, serum, and urine

Dimitrios Tsikas; Frank-Mathias Gutzki; Dirk O. Stichtenoth

2006-01-01

158

Hemin\\/nitrite\\/H 2O 2 induces brain homogenate oxidation and nitration: effects of some flavonoids  

Microsoft Academic Search

Oxidative injury has been implicated in the pathogenesis of numerous neurodegenerative diseases. Recently, it has been found that with the existence of hydrogen peroxide and nitrite, hemin catalyzes protein nitration. We hypothesize under certain pathological conditions, hemin catalyzed protein nitration may happen in the brain. In this paper, the effects of three flavonoids, i.e. quercetin, catachin and baicalein on hemin\\/nitrite\\/H2O2

Yuling Zhao; Zhonghong Gao; Hailing Li; Huibi Xu

2004-01-01

159

Nitrate, nitrite, and N-nitroso compounds in Finnish foods and the estimation of the dietary intakes  

Microsoft Academic Search

Zusammenfassung Die Einnahme von Nitrat, Nitrit undN-Nitroso-Verbindungen stützt sich auf die analytischen Werte der finnischen Lebensmittelkontrolle. Für die Schätzung der Nahrungsaufnahme der finnischen Bevölkerung benutzte man Resultate einer nationalen Nahrungsforschung und eines 48-Stunden-Befundes für 1768 Kinder und Jugendliche. Die durchschnittliche tägliche Einnahme von Nitrat schätzte man auf ungefähr 55 mg für die ganze Bevölkerung. Die durchschnittliche Einnahme von Nitrit betrug

Pirjo-Liisa Penttilä; Leena Räsänen; Sinikka Kimppa

1990-01-01

160

Dynamics of corrosion rates associated with nitrite or nitrate mediated control of souring under biological conditions simulating an oil reservoir  

Microsoft Academic Search

Representative microbial cultures from an oil reservoir and electrochemical techniques including potentiodynamic scan and linear polarization were used to investigate the time dependent corrosion rate associated with control of biogenic sulphide production through addition of nitrite, nitrate and a combination of nitrate-reducing, sulphide-oxidizing bacteria (NR-SOB) and nitrate. The addition of nitrate alone did not prevent the biogenic production of sulphide

C. L. Rempel; R. W. Evitts; M. Nemati

2006-01-01

161

Inhibition of Listeria monocytogenes using natural antimicrobials in no-nitrate-or-nitrite-added ham.  

PubMed

Consumer demand for foods manufactured without the direct addition of chemical preservatives, such as sodium nitrite and organic acid salts, has resulted in a unique class of "naturally" cured meat products. Formulation with a natural nitrate source and nitrate-reducing bacteria results in naturally cured processed meats that possess traits similar to conventionally cured meats. However, previous research has shown that the naturally cured products are more susceptible to pathogen growth. This study evaluated Listeria monocytogenes growth on ham manufactured with natural curing methods and with commercially available clean-label antimicrobials (cultured sugar and vinegar blend; lemon, cherry, and vinegar powder blend) and assessed impacts on physicochemical characteristics of the product. Hams made with either of the antimicrobials supported L. monocytogenes growth similar to that in the traditionally cured control (P > 0.05). Hams made with prefermented celery juice powder had the lowest residual nitrite concentrations (P < 0.05), and when no antimicrobial was added, L. monocytogenes growth was similar to that of the uncured control (P > 0.05). Aside from residual nitrite and nitrate concentrations, few physicochemical differences were identified. These findings show that ham can be produced with natural curing methods and antimicrobials to provide similar L. monocytogenes inhibition and physicochemical traits as in traditionally cured ham. PMID:22691474

Sullivan, Gary A; Jackson-Davis, Armitra L; Niebuhr, Steven E; Xi, Yuan; Schrader, Kohl D; Sebranek, Joseph G; Dickson, James S

2012-06-01

162

Natural abundance-level measurement of the nitrogen isotopic composition of oceanic nitrate: an adaptation of the ammonia diffusion method  

Microsoft Academic Search

We have adapted the “ammonia diffusion” method of nitrate extraction for natural-abundance level nitrogen isotopic measurement of oceanic nitrate. The method involves: (1) sample concentration (by boiling or evaporation); (2) conversion of nitrate to ammonia using Devarda's alloy; and (3) the gas-phase diffusion of ammonia onto an acidified glass fiber disk which is sandwiched between two porous Teflon membranes. We

D. M. Sigman; M. A. Altabet; R. Michener; D. C. McCorkle; B. Fry; R. M. Holmes

1997-01-01

163

Industrial use of molten nitrate/nitrite salts  

SciTech Connect

Nitrate salts have been used for years as a high-temperature heat transfer medium in the chemical and metal industries. This experience is often cited as an argument for the use of these salts in large-scale solar energy systems. However, this industrial experience has not been well documented and a study was carried out to provide such information to the solar community and to determine the applicability of this data base. Seven different industrial plants were visited and the plant operators were interviewed with regard to operating history and experience. In all cases the molten salt systems operate without problems. However, it is not possible to apply the base of industrial experience directly to solar thermal energy applications because of differences in operating temperature, salt composition, alloys used, and thermal/mechanical conditions.

Carling, R.W.; Mar, R.W.

1981-12-01

164

Implications of nitrate and nitrite isotopic measurements for the mechanisms of nitrogen cycling in the Peru oxygen deficient zone  

NASA Astrophysics Data System (ADS)

Oceanic oxygen deficient zones (ODZs) are important regions for oceanic primary productivity, nitrous oxide (N2O) production, and the marine nitrogen (N) budget. These areas are recognized as hotspots for fixed N loss, although the rates and mechanisms of N loss have been difficult to quantify. Stable isotopes of nitrate and nitrite integrate the effects of a complex suite of processes occurring in these regions. Here we examine the distributions of nitrate ?15N and ?18O and nitrite ?15N in the Peruvian ODZ. Our data reveal elevated nitrate ?15N and ?18O values, particularly after correcting for the isotopic contribution of nitrite. Moreover, the isotopic composition of nitrite, a central intermediate in the marine N cycle, provides an additional constraint on the processes occurring in the Peru ODZ. A simple finite difference model is used to interpret the mechanisms and relative rates of N transformation in the waters sampled off the coast of Peru. Nitrite oxidation is found to be an important sink for nitrite, in many cases exceeding the rate of nitrite reduction. In model results, the apparent isotope effect for nitrate reduction, as inferred from a closed system Rayleigh model of nitrate concentration and ?15N, is greater than the prescribed value due to the effects of nitrite oxidation. Accordingly, the isotope effect for nitrate reduction that best fits the data is 12‰, much lower than the commonly inferred 25‰. Furthermore, nitrite oxidation may mediate the ?15N of N2 produced in this water column suboxic zone through its effect on the ?15N values of NO2- and NO3-.

Casciotti, Karen L.; Buchwald, Carolyn; McIlvin, Matthew

2013-10-01

165

Intake of nitrate and nitrite and the risk of gastric cancer: a prospective cohort study.  

PubMed Central

The association between the intake of nitrate or nitrite and gastric cancer risk was investigated in a prospective cohort study started in 1986 in the Netherlands, of 120,852 men and women aged 55-69 years. At baseline, data on dietary intake, smoking habits and other covariates were collected by means of a self-administered questionnaire. For data analysis, a case-cohort approach was used, in which the person-years at risk were estimated from a randomly selected subcohort (1688 men and 1812 women). After 6.3 years of follow-up, 282 microscopically confirmed incident cases of stomach cancer were detected: 219 men and 63 women. We did not find a higher risk of gastric cancer among people with a higher nitrate intake from food [rate ratio (RR) highest/lowest quintile = 0.80, 95% CI 0.47-1.37, trend-P = 0.18], a higher nitrate intake from drinking water (RR highest/lowest quintile = 0.88, 95% CI 0.59-1.32, trend-P = 0.39) or a higher intake of nitrite (RR highest/lowest quintile = 1.44, 95% CI 0.95-2.18, trend-P = 0.24). Rate ratios for gastric cancer were also computed for each tertile of nitrate intake from foods within tertiles of vitamin C intake and intake of beta-carotene, but no consistent pattern was found. Therefore, our study does not support a positive association between the intake of nitrate or nitrite and gastric cancer risk.

van Loon, A. J.; Botterweck, A. A.; Goldbohm, R. A.; Brants, H. A.; van Klaveren, J. D.; van den Brandt, P. A.

1998-01-01

166

Modification of nitrifying biofilm into nitritating one by combination of increased free ammonia concentrations, lowered HRT and dissolved oxygen concentration.  

PubMed

Nitrifying biomass on ring-shaped carriers was modified to nitritating one in a relatively short period of time (37 days) by limiting the air supply, changing the aeration regime, shortening the hydraulic retention time and increasing free ammonia (FA) concentration in the moving-bed biofilm reactor (MBBR). The most efficient strategy for the development and maintenance of nitritating biofilm was found to be the inhibition of nitrifying activity by higher FA concentrations (up to 6.5 mg/L) in the process. Reject water from sludge treatment from the Tallinn Wastewater Treatment Plant was used as substrate in the MBBR. The performance of high-surfaced biocarriers taken from the nitritating activity MBBR was further studied in batch tests to investigate nitritation and nitrification kinetics with various FA concentrations and temperatures. The maximum nitrite accumulation ratio (96.6%) expressed as the percentage of NO2(-)-N/NOx(-)-N was achieved for FA concentration of 70 mg/L at 36 degrees C. Under the same conditions the specific nitrite oxidation rate achieved was 30 times lower than the specific nitrite formation rate. It was demonstrated that in the biofilm system, inhibition by FA combined with the optimization of the main control parameters is a good strategy to achieve nitritating activity and suppress nitrification. PMID:22125903

Zekker, Ivar; Rikmann, Ergo; Tenno, Toomas; Menert, Anne; Lemmiksoo, Vallo; Saluste, Alar; Tenno, Taavo; Tomingas, Martin

2011-01-01

167

Control of hydrogen sulfide production in oil fields by managing microbial communities through nitrate or nitrite addition  

NASA Astrophysics Data System (ADS)

Nitrate or nitrite injection into oil reservoirs during water flooding has the potential to control biological souring, the production of hydrogen sulfide (H2S) by sulfate-reducing bacteria (SRB). Souring control is essential because sulfide is toxic, sulfide precipitates can plug reservoir formations, souring lowers crude oil value, and SRB induce corrosion. Nitrate and nitrite can stimulate heterotrophic nitrate- or nitrite-reducing bacteria (hNRB) and nitrate- or nitrite-reducing, sulfide oxidizing bacteria (NRSOB). Nitrite also inhibits SRB activity by blocking the sulfate reduction pathway. Continuous up-flow packed-bed bioreactors were inoculated with produced water from the Coleville oil field to establish sulfide-producing biofilms similar to those found in sour reservoirs. Nitrate or nitrite addition to bioreactors indicated that the dose required for hNRB or NR-SOB to control souring depended on the concentration of oil organics. Either mechanism mediates the net removal of oil organics (lactate) with nitrate or nitrite, with lower doses of nitrate required due to its greater oxidative power. Microbial community analysis by reverse sample genome probing (RSGP) revealed that NR-SOB mediated sulfide removal at low nitrate or nitrite concentrations when lactate was still available to SRB and the redox potential was low. At high nitrate doses hNRB oxidized lactate directly, produced nitrite and maintained a high redox potential, thus excluding SRB activity. Facultatively chemolithotrophic Campylobacter sp. strains were isolated from the bioreactors and incorporated into RSGP analyses, revealing their dominance in both NR-SOB- and hNRB-containing communities. The metabolic flexibility of these strains may confer a competitive advantage over obligate chemolithotrophs like Thiomicrospira sp. strain CVO or hNRB that do not have NR-SOB activity like newly isolated Thauera sp. and Rhodobacter sp. strains. A single high dose of nitrite resulted in immediate inhibition of SRB that was independent of hNRB or NR-SOB. Examination of corrosion coupons following bioreactor experiments revealed that nitrite inhibition was the only mechanism that prevented both souring and corrosion. Sulfide elimination by hNRB or NR-SOB resulted in increased pitting corrosion in the region of greatest microbial activity. These findings are instructive for designing souring control treatments and improve understanding of oil field microbial communities.

Hubert, Casey R. J.

168

Containment of biogenic sulfide production in continuous up-flow packed-bed bioreactors with nitrate or nitrite.  

PubMed

Produced water from the Coleville oil field in Saskatchewan, Canada was used to inoculate continuous up-flow packed-bed bioreactors. When 7.8 mM sulfate and 25 mM lactate were present in the in-flowing medium, H(2)S production (souring) by sulfate-reducing bacteria (SRB) was prevented by addition of 17.5 mM nitrate or 20 mM nitrite. Changing the sulfate or lactate concentration of the in-flowing medium indicated that the concentrations of nitrate or nitrite required for containment of souring decreased proportionally with a lowered concentration of the electron donor lactate, while the sulfate concentration of the medium had no effect. Microbial communities were dominated by SRB. Nitrate addition did not give rise to changes in community composition, indicating that lactate oxidation and H(2)S removal were caused by the combined action of SRB and nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). Apparently the nitrite concentrations formed by these NR-SOB did not inhibit the SRB sufficiently to cause community shifts. In contrast, significant community shifts were observed upon direct addition of high concentrations (20 mM) of nitrite. Strains NO3A and NO2B, two newly isolated, nitrate-reducing bacteria (NRB) emerged as major community members. These were found to belong to the epsilon-division of the Proteobacteria, to be most closely related to Campylobacter lari, and to oxidize lactate with nitrate or nitrite as the electron acceptor. Thus the mechanism of microbial H(2)S removal in up-flow packed-bed bioreactors depended on whether nitrate (SRB/NR-SOB) or nitrite (SRB/NR-SOB as well as NRB) was used. However, the amount of nitrate or nitrite needed to completely remove H(2)S was dictated by the electron donor (lactate) concentration, irrespective of mechanism. PMID:12675569

Hubert, Casey; Nemati, Mehdi; Jenneman, Gary; Voordouw, Gerrit

169

Potential and limitations of ozone for the removal of ammonia, nitrite, and yellow substances in marine recirculating aquaculture systems  

Microsoft Academic Search

The high levels of water-reuse in intensive recirculating aquaculture systems (RAS) require an effective water treatment in order to maintain good water quality. In order to reveal the potential and limitations of ozonation for water quality improvement in marine RAS, we tested ozone's ability to remove nitrite, ammonia, yellow substances and total bacterial biomass in seawater, considering aspects such as

J. P. Schroeder; P. L. Croot; B. Von Dewitz; U. Waller; R. Hanel

2011-01-01

170

TOLERANCE OF JUVENILE BLACK SEA BASS CENTROPRISTIS STRIATA TO ACUTE AMMONIA AND NITRITE EXPOSURE AT VARIOUS SALINITIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Experiments were conducted to determine the acute tolerance of juvenile (mean weight ± SE, 9.9 ± 0.9 g) black sea bass (Centropristis striata) to environmental un-ionized ammonia-nitrogen (NH3-N) and nitrite-nitrogen (NO2-N) exposure at various salinities. Specifically, median lethal concentrations...

171

Sample Pretreatment with Nitrate Reductase and Glucose6Phosphate Dehydrogenase Quantitatively Reduces Nitrate While Avoiding Interference by NADP + When the Griess Reaction Is Used to Assay for Nitrite  

Microsoft Academic Search

An assay for the simultaneous measurement of nitrite and nitrate, products of nitric oxide metabolism, is described. Others have reported pretreating sample by using nitrate reductase (NR) and NADPH to reduce endogenous NO?3 before assaying the resultant NO?2 using the Griess reaction. However, we found that the NADP+ formed during pretreatment interfered with the Griess reaction when NADPH was used

C. P. Verdon; B. A. Burton; R. L. Prior

1995-01-01

172

Determination of low level nitrite and nitrate in biological, food and environmental samples by gas chromatography–mass spectrometry and liquid chromatography with fluorescence detection  

Microsoft Academic Search

Gas chromatography–mass spectrometry (GC–MS) and liquid chromatography with fluorescence detection (LC-FL) methods have been proposed for the determination of low level nitrite and nitrate in biological, food and environmental samples. The methods include derivatization of aqueous nitrite with 2,3-diaminonaphthalene (DAN), enzymatic reduction of nitrate to nitrite, extraction with toluene and chromatographic analyses of highly fluorescent 2,3-naphthotriazole (NAT) derivative of nitrite

Mehmet Akyüz; ?evket Ata

2009-01-01

173

A heme-C-containing enzyme complex that exhibits nitrate and nitrite reductase activity from the dissimilatory iron-reducing bacterium Geobacter metallireducens  

Microsoft Academic Search

Nitrate reduction in the dissimilatory iron-reducing bacterium Geobacter metallireducens was investigated. Nitrate reductase and nitrite reductase activities in nitrate-grown cells were detected only in the membrane\\u000a fraction. The apparent K\\u000a \\u000a m values for nitrate and nitrite were determined to be 32 and 10 ?M, respectively. Growth on nitrate was not inhibited by either\\u000a tungstate or molybdate at concentrations of 1

Francisco Martínez Murillo; Theresa Gugliuzza; John Senko; Partha Basu; John F. Stolz

1999-01-01

174

Nitrite oxidation in the Namibian oxygen minimum zone.  

PubMed

Nitrite oxidation is the second step of nitrification. It is the primary source of oceanic nitrate, the predominant form of bioavailable nitrogen in the ocean. Despite its obvious importance, nitrite oxidation has rarely been investigated in marine settings. We determined nitrite oxidation rates directly in (15)N-incubation experiments and compared the rates with those of nitrate reduction to nitrite, ammonia oxidation, anammox, denitrification, as well as dissimilatory nitrate/nitrite reduction to ammonium in the Namibian oxygen minimum zone (OMZ). Nitrite oxidation (?372 nM NO(2)(-) d(-1)) was detected throughout the OMZ even when in situ oxygen concentrations were low to non-detectable. Nitrite oxidation rates often exceeded ammonia oxidation rates, whereas nitrate reduction served as an alternative and significant source of nitrite. Nitrite oxidation and anammox co-occurred in these oxygen-deficient waters, suggesting that nitrite-oxidizing bacteria (NOB) likely compete with anammox bacteria for nitrite when substrate availability became low. Among all of the known NOB genera targeted via catalyzed reporter deposition fluorescence in situ hybridization, only Nitrospina and Nitrococcus were detectable in the Namibian OMZ samples investigated. These NOB were abundant throughout the OMZ and contributed up to ~9% of total microbial community. Our combined results reveal that a considerable fraction of the recently recycled nitrogen or reduced NO(3)(-) was re-oxidized back to NO(3)(-) via nitrite oxidation, instead of being lost from the system through the anammox or denitrification pathways. PMID:22170426

Füssel, Jessika; Lam, Phyllis; Lavik, Gaute; Jensen, Marlene M; Holtappels, Moritz; Günter, Marcel; Kuypers, Marcel M M

2011-12-15

175

Promotion of Seed Germination by Nitrate, Nitrite, Hydroxylamine, and Ammonium Salts 1  

PubMed Central

Action and uptake of azides, nitrates, nitrites, hydroxylamines, and ammonium salts were measured on germination of Amaranthus albus, Lactuca sativa, Phleum pratense, Barbarea vulgaris, B. verna, and Setaria glauca seeds. Nitrate and nitrite reductase activities were measured in vivo for each of these kinds of seeds. Activities were measured in vitro for catalase, peroxidase, glycolate oxidase, and pyridine nucleotide quinone reductase on extracts of A. albus and L. sativa seeds before and after germination. The enzymic activities measured and the responsiveness of the haemproteins to inhibition by the several compounds indicate that nitrites, azides, and hydroxylamines promote seed germination by inhibition of H2O2 decomposition by catalase. Ammonium salts showed pronounced promotive activity only for B. verna and B. vulgaris seeds, for which they served as metabolic substrates. The promotion of germination is thought to depend on coupling of peroxidase action to NADPH oxidation, which can regulate the pentose pathway of d-glucose 6-phosphate use. Pyridine nucleotide quinone reductase is the possible coupling enzyme. This enzyme and others required for the action are present in the seeds before imbibition of water.

Hendricks, S. B.; Taylorson, R. B.

1974-01-01

176

Dissimilatory hexaheme c nitrite reductase of “Spirillum” strain 5175: purification and properties  

Microsoft Academic Search

When grown with nitrate as terminal electron acceptor both the soluble (periplasm, cytoplasm) and the membrane fraction of “Spirillum” strain 5175 exhibited high nitrite reductase activity. The nitrite reductase obtained from the soluble fraction was purified 76-fold to electrophoretical homogeneity. The enzyme reduced nitrite to ammonia with a specific activity of 723 µmol NOinf2sup-× (mg protein × min)-1. The molecular

Wolfram Schumacher; Peter M. H. Kroneck

1991-01-01

177

Chemical reactivity of nitrates and nitrites towards TBP and potassium nickel ferrocyanide between 30 and 300 deg  

SciTech Connect

Since the late sixties, bitumen has been widely used by the nuclear industry as a matrix for the immobilization of low- and intermediate level radioactive waste originating mainly from the nuclear activities: precipitation or evaporator concentrates, ion exchange resins, incinerator ashes, and filter materials. Depending on bitumen and operating conditions, bituminization of radioactive waste can be operated between 130 and 180 deg. C, so chemical reaction can be induced with nitrate or nitrite towards elements contained in waste (TPB, potassium nickel ferrocyanide and cobalt compound) and bitumen. These reactions are mainly exothermic this is the reason why the enthalpy reaction and their temperature of initiation have to be determined independently of their concentration in waste. In this work, we have studied by Calvet Calorimetry at 0.1 deg. C/min heating rates, the behaviour of chemical elements especially oxido-reduction couples that can react at a temperature range 100- 300 deg. C (Nitrate/PPFeNi, Nitrite/PPFeNi, Nitrate/TBP, Nitrite/TBP, Nitrate/bitumen and Nitrite/bitumen). The initial temperature reaction of nitrates or nitrites towards potassium nickel ferrocyanide (PPFeNi) has been studied and is equal respectively to 225 deg. C and 175 deg. C. Because of the large scale temperature reaction of nitrate and PPFeNi, enthalpy reaction can not be calculated, although enthalpy reaction of nitrite and PPFeNi is equal to 270 kJ/mol of nitrite. Sodium Nitrate and TBP behaviour has been investigated, and an exothermic reaction at 135 deg. C until 250 deg. C is evidenced. The exothermic energy reaction is a function of TBP concentration and the enthalpy reaction has been determined. (authors)

Lambertin, D.; Chartier, D.; Joussot-Dubien, C. [CEA Valrho, DTCD/SPDE/L2ED, 30 - Bagnols sur Ceze (France)

2007-07-01

178

Nitrate\\/Nitrite Assimilation System of the Marine Picoplanktonic Cyanobacterium Synechococcus sp. Strain WH 8103: Effect of Nitrogen Source and Availability on Gene Expression  

Microsoft Academic Search

The genes encoding the structural components of the nitrate\\/nitrite assimilation system of the oceanic cyanobacterium Synechococcus sp. strain WH 8103 were cloned and characterized. The genes encoding nitrate reductase (narB) and nitrite reductase (nirA) are clustered on the chromosome but are organized in separate transcriptional units. Upstream of narB is a homologue of nrtP that encodes a nitrate\\/nitrite-bispecific permease rather

Clare Bird; Michael Wyman

2003-01-01

179

Endogenous levels of nitrites and nitrates in wide consumption foodstuffs: Results of five years of official controls and monitoring.  

PubMed

The massive introduction of nitrogen fertilisers, necessary to maximise the global food production, has brought about an increase of the residual amounts of nitrites and nitrates in the products. Notoriously, these compounds may exercise toxic effects. In this work the results obtained from 5years of official controls and monitoring focused on tracing quantifiable amounts of nitrites and nitrates in 1785 samples of meat, dairy, fish products and leafy vegetables are reported. A widespread presence of nitrates at low concentrations in foodstuffs was verified. High concentrations of nitrates were registered in some leafy vegetables and mussels samples, while high nitrites concentrations were registered in some spinach samples. The results confirmed the necessity to develop most controls and suggest the introduction of new legal limits related to some combinations contaminant/matrix. Such new limits may fill legislative gaps that may cause wrong interpretations of the results obtained during official controls. PMID:23692764

Iammarino, Marco; Di Taranto, Aurelia; Cristino, Marianna

2012-11-10

180

Enriched Nitrate and Depleted Nitrite Isotopic Signatures in the OMZ off Northern Chile  

NASA Astrophysics Data System (ADS)

The vast majority of fixed nitrogen loss from the ocean’s water-column occurs in the O2 minimum zones of the Arabian Sea and the eastern tropical North and South Pacific (ETNP and ETSP). In these regions, subsurface O2 concentrations reach suboxic levels that favor microbial production of N2 gas from combined N sources via heterotrophic denitrification and anammox. One of the most intense oxygen minimum zones (OMZ) is found in the ETSP, especially off northern Chile, where O2 depleted waters can reach into the photic zone as a result of coastal upwelling and a narrow continental shelf. Despite the importance of these regions there still remains much uncertainty about N cycling in these regions. We present ?15N and ?18O isotope data for nitrate and ?15N data for nitrite, which along with corroborating relative gene abundances from metagenomes provide insight into N-cycling processes both within and above the OMZ. Depth profiles showed some of the highest ?15N nitrate values seen to date in an OMZ (up to 32‰), which has implications for tracing denitrification related biogeochemical signals throughout the Pacific and for downcore recording of past changes in OMZ intensity. Co-occurring nitrite ?15N in the OMZ fell in the range -6 to -20‰, resulting in a ?15N offset between co-occurring nitrate and nitrite in the range 30 to 40‰. This offset is greater than that expected from heterotrophic denitrification alone, implying either a larger isotope effect for the first enzymatic step in denitrification (NO3- reduction to NO2-) than previously estimated from field and culture studies or, more likely, that additional processes are enhancing this separation. NO3- consumption by heterotrophic denitrification has been shown to increase both ?15N and ?18O of nitrate in a 1:1 ratio. The slope for samples in the OMZ off northern Chile show a clear but surprisingly negative deviation from the expected slope of 1, again suggesting additional processes are occurring in this region of the water column. A number of processes including anammox, organic matter remineralization, and nitrification will be discussed in an attempt to explain these deviations. Complex nitrite and nitrate interactions will also be discussed with respect to the surface waters and the oxycline.

Bristow, L. A.; Altabet, M. A.; Stewart, F.; Delong, E.; Ulloa, O.

2010-12-01

181

The YNT1 gene encoding the nitrate transporter in the yeast Hansenula polymorpha is clustered with genes YNI1 and YNR1 encoding nitrite reductase and nitrate reductase, and its disruption causes inability to grow in nitrate.  

PubMed Central

DNA sequencing in the phage lambda JA13 isolated from a lambda EMBL3 Hansenula polymorpha genomic DNA library containing the nitrate reductase-(YNR1) and nitrite reductase-(YNI1) encoding genes revealed an open reading frame (YNT1) of 1524 nucleotides encoding a putative protein of 508 amino acids with great similarity to the nitrate transporters from Aspergillus nidulans and Chlamydomonas reinhardtii. Disruption of the chromosomal YNT1 copy resulted in incapacity to grow in nitrate and a significant reduction in rate of nitrate uptake. The disrupted strain is still sensitive to chlorate, and, in the presence of 0.1 mM nitrate, the expression of YNR1 and YNI1 and the activity of nitrate reductase and nitrite reductase are significantly reduced compared with the wild-type. Northern-blot analysis showed that YNT1 is expressed when the yeast is grown in nitrate and nitrite but not in ammonium solution.

Perez, M D; Gonzalez, C; Avila, J; Brito, N; Siverio, J M

1997-01-01

182

A high-throughput assay format for determination of nitrate reductase and nitrite reductase enzyme activities  

SciTech Connect

The authors describe a microplate-based high-throughput procedure for rapid assay of the enzyme activities of nitrate reductase and nitrite reductase, using extremely small volumes of reagents. The new procedure offers the advantages of rapidity, small sample size-nanoliter volumes, low cost, and a dramatic increase in the throughput sample number that can be analyzed simultaneously. Additional advantages can be accessed by using microplate reader application software packages that permit assigning a group type to the wells, recording of the data on exportable data files and exercising the option of using the kinetic or endpoint reading modes. The assay can also be used independently for detecting nitrite residues/contamination in environmental/food samples. 10 refs., 2 figs.

McNally, N.; Liu, Xiang Yang; Choudary, P.V. [Univ. of California, Davis, CA (United States)

1997-01-01

183

Dynamics of corrosion rates associated with nitrite or nitrate mediated control of souring under biological conditions simulating an oil reservoir.  

PubMed

Representative microbial cultures from an oil reservoir and electrochemical techniques including potentiodynamic scan and linear polarization were used to investigate the time dependent corrosion rate associated with control of biogenic sulphide production through addition of nitrite, nitrate and a combination of nitrate-reducing, sulphide-oxidizing bacteria (NR-SOB) and nitrate. The addition of nitrate alone did not prevent the biogenic production of sulphide but the produced sulphide was eventually oxidized and removed from the system. The addition of nitrate and NR-SOB had a similar effect on oxidation and removal of sulphide present in the system. However, as the addition of nitrate and NR-SOB was performed towards the end of sulphide production phase, the assessment of immediate impact was not possible. The addition of nitrite inhibited the biogenic production of sulphide immediately and led to removal of sulphide through nitrite mediated chemical oxidation of sulphide. The real time corrosion rate measurement revealed that in all three cases an acceleration in the corrosion rate occurred during the oxidation and removal of sulphide. Amendments of nitrate and NR-SOB or nitrate alone both gave rise to localized corrosion in the form of pits, with the maximum observed corrosion rates of 0.72 and 1.4 mm year(-1), respectively. The addition of nitrite also accelerated the corrosion rate but the maximum corrosion rate observed following nitrite addition was 0.3 mm year(-1). Furthermore, in the presence of nitrite the extent of pitting was not as high as those observed with other control methods. PMID:16758172

Rempel, C L; Evitts, R W; Nemati, M

2006-06-07

184

Measurement of Plasma Nitrite by Chemiluminescence without Interference of S-, N-nitroso and Nitrated Species  

PubMed Central

Recent studies have demonstrated that plasma nitrite (NO2-) reflects endothelial nitric oxide synthase activity and it has been proposed as a prognostic marker for cardiovascular disease. In addition, NO2- itself has been shown to have biological activities thought to be triggered by reduction back to NO in blood and tissues. The development of sensitive and reproducible methods for the quantitative determination of plasma NO2- is, therefore, of great importance. Ozone-based chemiluminescence assays have been shown to be highly sensitive for the determination of nanomolar quantities of NO and NO related species in biological fluids. We report here an improved direct chemiluminescence method for the determination of plasma NO2- without interference of other nitric oxide related species such as nitrate, S-nitrosothiols, N-nitrosamines, nitrated proteins and nitrated lipids. The method involves a reaction system consisting of glacial acetic acid and ascorbic acid in the purge vessel of the NO analyzer. Under these acidic conditions NO2- is stoichiometrically reduced to NO by ascorbic acid. Fasting human plasma NO2- values were found in the range of 56-210 nM (mean =110 ± 36 nM). This method has high sensitivity with an accuracy of 97% and high precision (C.V <10%) for determination of plasma nitrite. The present method is simple and highly specific for plasma NO2-. It is particularly suited to evaluate vasculature endothelial NO production that predicts the risks for cardiovascular disease.

Nagababu, Enika; Rifkind, Joseph M.

2009-01-01

185

Cured meat products without direct addition of nitrate or nitrite: what are the issues?  

PubMed

The growing popularity of food products marketed in the United States as "natural" and "organic" has resulted in a proliferation of marketing efforts to meet consumer demands for these foods. Because natural and organic foods are not permitted to use chemical preservatives, the traditional curing agents used for cured meats, nitrate and/or nitrite, cannot be added to natural and organic processed meat products. However, alternative processes that utilize ingredients with high nitrate content, such as vegetable-based ingredients, and a nitrate-reducing starter culture can produce processed meats with very typical cured meat properties. Because it is not possible to analytically measure the amount of nitrite produced by this process, several potential issues deserve consideration. Regulations, for example, should permit labeling that accurately reflects the process and products, manufacturing procedures must be standardized to achieve product consistency, marketing efforts should clearly communicate the nature of these products to consumers, product quality must be maintained, and microbiological safety must be assured. PMID:22061404

Sebranek, Joseph G; Bacus, James N

2007-04-14

186

Cerebrospinal fluid concentrations of nitrate plus nitrite during the treatment of acute lymphoblastic leukaemia in childhood.  

PubMed

To investigate the hypothesis that acute lymphoblastic leukaemia (ALL) and its treatment disturb central nervous system nitric oxide metabolism, 11 patients were studied. Serial cerebrospinal fluid (CSF) samples were collected throughout treatment and the concentration of nitrate plus nitrite (NOx) was measured. Compared to an age-matched reference population, CSF NOx was significantly increased before treatment and rose further during the induction phase of treatment. Concentrations remained high during consolidation treatment, but fell during continuing treatment and normalised by the end of treatment. In conclusion, ALL and its treatment cause an increase in central nervous system nitric oxide production. reserved. PMID:9680103

Surtees, R; Clelland, J; Heales, S

1998-08-01

187

Acute blood pressure lowering, vasoprotective and anti-platelet properties of dietary nitrate via bioconversion to nitrite  

PubMed Central

Diets rich in fruits and vegetables reduce blood pressure (BP) and the risk of adverse cardiovascular events. However, the mechanisms of this effect have not been elucidated. Certain vegetables possess a high nitrate content and we hypothesized that this might represent a source of vasoprotective nitric oxide via bioactivation. In healthy volunteers, approximately 3h following ingestion of a dietary nitrate load (beetroot juice 500ml) BP was substantially reduced (?max - 10.4/8 mmHg); an effect that correlated with peak increases in plasma nitrite concentration. The dietary nitrate load also prevented endothelial dysfunction induced by an acute ischemic insult in the human forearm and significantly attenuated ex vivo platelet aggregation in response to collagen and ADP. Interruption of the enterosalivary conversion of nitrate to nitrite (facilitated by bacterial anaerobes situated on the surface of the tongue), prevented the rise in plasma nitrite, blocked the decrease in BP and abolished the inhibitory effects on platelet aggregation, confirming that these vasoprotective effects were due to the activity of nitrite converted from the ingested nitrate. These findings suggest that dietary nitrate underlies the beneficial effects of a vegetable-rich diet and highlights the potential of a ‘natural’, low cost approach for the treatment of cardiovascular disease.

Webb, Andrew J; Patel, Nakul; Loukogeorgakis, Stavros; Okorie, Mike; Aboud, Zainab; Misra, Shivani; Rashid, Rahim; Miall, Philip; Deanfield, John; Benjamin, Nigel; MacAllister, Raymond; Hobbs, Adrian J; Ahluwalia, Amrita

2010-01-01

188

A seven-gene operon essential for formate-dependent nitrite reduction to ammonia by enteric bacteria.  

PubMed

The DNA sequence of the regulatory region and the structural gene, nrfA, for cytochrome c552 of Escherichia coli K-12 have been reported. We have now established that nrfA is the first gene in a seven-gene operon, designated the nrf operon, at least five of which are essential for formate-dependent nitrite reduction to ammonia. This operon terminates just upstream of the previously sequenced gltP gene encoding a sodium-independent, glutamate and aspartate transporter. Expression of lac fused to nrfA, nrfE or nrfG is regulated by oxygen repression, FNR-dependent anaerobic induction, nitrite induction and nitrate repression during anaerobic growth, exactly as previously reported for the nrfA promoter. In contrast, expression of the gltP-lac fusion was FNR-independent. The open reading frame immediately downstream of nrfA encodes NrfB, a hydrophilic, penta-haem cytochrome c with an M(r) of 20,714. The structure of the N-terminal region is typical of a signal peptide for a periplasmic protein: cleavage at the putative signal peptide cleavage site, Ala-26, would result in a periplasmic cytochrome with a molecular mass of 18 kDa. The NrfC polypeptide, M(r) 24,567, contains 16 cysteine residues arranged in four clusters typical of the CooF super-family of non-haem iron-sulphur proteins. The NrfD sequence predicts a 318-residue hydrophobic protein with a distribution of acidic and basic amino acids which suggests that NrfD is an integral transmembrane protein with loops in both the periplasm and the cytoplasm. Proteins most similar to NrfD include the PsrC subunit of polysulphide reductase from Wolinella, but, as seven of the 10 most similar proteins are NADH-ubiquinone oxidoreductases, we propose that NrfD participates in the transfer of electrons from the quinone pool into the terminal components of the Nrf pathway. NrfE, M(r) 60,851, is predicted to be another hydrophobic, integral membrane protein homologous to the CdI1 protein of Rhodobacter capsulatus, which has been implicated in the assembly of periplasmic c-type cytochromes. The sequence of the 127 residue NrfF polypeptide, M(r) 14,522, is strikingly similar to the CcI2 protein of R. capsulatus, especially in the putative haem-binding motif, RCPQCQNQN.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8057835

Hussain, H; Grove, J; Griffiths, L; Busby, S; Cole, J

1994-04-01

189

Plasma Levels of Nitrite and Nitrate in Early and Recent Classes of Fish  

PubMed Central

The stable metabolite of nitric oxide in plasma is NOx, the sum of nitrite plus nitrate. Measures of plasma NOx may provide information about the nitric oxide tonus of the entire endothelium including capillary microvessels. Although data are available for mammalian species, plasma NOx measurements in early vertebrate species are scarce. The purpose of this study was to test the hypothesis that plasma NOx would be similar to the NOx in the water environment for fish in early classes (Agnatha and Chondrichthye) and would exceed water NOx levels in the known nitrite-sensitive fish (Osteichthye). Plasma samples were obtained from 18 species of adult fish (n = 167) and from their housing or natural water environment. NOx was measured by using chemiluminescence. Plasma NOx was detected in all species and ranged from 0.5 nmol/ml (skate) to 453.9 nmol/ml (shortnose gar). Average plasma NOx was significantly higher in sea lamprey than in Atlantic hagfish whereas that of little skate was 3-fold lower than in spiny dogfish shark. Plasma NOx differed significantly among early bony fish (paddlefish, pallid sturgeon, gar) yet was similar among modern bony fish, with the exception of rainbow trout. Plasma NOx reflected water NOx in only 2 species (hagfish and shark), and levels did not coincide with nitrite sensitivity. This study provides an expanded comparative view of plasma NOx levels across 3 groups of early fish. The data obtained suggest a nitric oxide system in early and modern fish.

Williams, Donna A; Flood, Mary H; Lewis, Debra A; Miller, Virginia M; Krause, William J

2008-01-01

190

Role of nitrite reductase in the ammonia-oxidizing pathway of Nitrosomonas europaea.  

PubMed

Metabolism of ammonia (NH(3)) and hydroxylamine (NH(2)OH) by wild-type and a nitrite reductase (nirK) deficient mutant of Nitrosomonas europaea was investigated to clarify the role of NirK in the NH(3) oxidation pathway. NirK-deficient N. europaea grew more slowly, consumed less NH(3), had a lower rate of nitrite (NO(2) (-)) production, and a significantly higher rate of nitrous oxide (N(2)O) production than the wild-type when incubated with NH(3) under high O(2) tension. In incubations with NH(3) under low O(2) tension, NirK-deficient N. europaea grew more slowly, but had only modest differences in NH(3) oxidation and product formation rates relative to the wild-type. In contrast, the nirK mutant oxidized NH(2)OH to NO(2) (-) at consistently slower rates than the wild-type, especially under low O(2) tension, and lost a significant pool of NH(2)OH-N to products other than NO(2) (-) and N(2)O. The rate of N(2)O production by the nirK mutant was ca. three times higher than the wild-type during hydrazine-dependent NO(2) (-) reduction under both high and low O(2) tension. Together, the results indicate that NirK activity supports growth of N. europaea by supporting the oxidation of NH(3) to NO(2) (-) via NH(2)OH, and stimulation of hydrazine-dependent NO(2) (-) reduction by NirK-deficient N. europaea indicated the presence of an alternative, enzymatic pathway for N(2)O production. PMID:17541778

Cantera, J Jason L; Stein, Lisa Y

2007-06-01

191

The role of nitrite and nitrate ions as photosensitizers in the phototransformation of phenolic compounds in seawater.  

PubMed

Nitrite and nitrate are known to be involved in photochemical processes occurring in natural waters. In this study we have investigated the role played by these photosensitizers towards the transformation of xenobiotic organic matter in marine water, with the goal of assessing the typical transformation routes induced in seawater by irradiated nitrite/nitrate. For this purpose, phenol was chosen as model molecule. Phenol transformation was investigated under simulated solar radiation in the presence of nitrite (in the range of 1 × 10(-5)-1 × 10(-2)M) or nitrate ions, in pure water at pH 8, in artificial seawater (containing same dissolved salts as seawater but no organic matter), and in natural seawater. In all experiments, phenol degradation rate and formation of intermediates were assessed. As expected, phenol disappearance rate decreased with decreasing nitrite concentration and was slightly reduced by the presence of chloride. Other salts present in artificial seawater (e.g. HCO(3)(-), CO(3)(2-) and Br(-)) had a more marked effect on phenol transformation. Analysis of intermediates formed in the different matrices under study showed generation of hydroxyl-, nitro- and chloroderivatives of phenol, to a different extent depending on experimental conditions. 1,4-Benzoquinone prevailed in all cases, nitroderivatives were only formed with nitrite but were not detected in nitrate-spiked solutions. Competition was observed between halogenation and nitration of phenol, with variable outcome depending on nitrite concentration. The most likely reason is competition between nitrating and halogenating species for reaction with the phenoxyl radical. A kinetic model able to justify the occurrence of different intermediates under the adopted conditions is presented and discussed. PMID:23063640

Calza, P; Vione, D; Novelli, A; Pelizzetti, E; Minero, C

2012-10-11

192

High-resolution microanalysis of nitrite and nitrate in neuronal tissues by capillary electrophoresis with conductivity detection.  

PubMed

Nitrites and nitrates are widely used reporters of endogenous activity of nitric oxide synthases (NOS), an important group of enzymes producing the gaseous signal molecule nitric oxide (NO). However, due to the great chemical heterogeneity of neuronal tissues, standard analytical protocols for evaluation of neuronal nitrite/nitrate concentrations are inefficient. We optimized a high-performance capillary zone electrophoresis (CZE) technique to analyze nitrite/nitrate concentrations in submicroliter samples from mammalian neuronal tissues. The measurements were made using a PrinCE 476 computerized capillary electrophoresis system with a Crystal 1000 contact conductivity detector. Isotachophoretic stacking injection of 1000- to 10000-fold diluted samples, which had been pretreated with a custom-designed solid-phase microextraction (SPME) cartridge, was employed to assay micromolar and nanomolar nitrite and nitrate levels in the presence of the high millimolar chloride concentrations characteristic of many biological samples. In the presented technique, a 10-microl volume of diluted ganglionic sample was used for chloride removal and sample cleanup. The method yields high analytical performance, including good reproducibility, resolution, and accuracy. The limits of detection relative to undiluted sample matrix were 8.9 nM (0.41 ppb) and 3.54 nM (0.22 ppb) for nitrite and nitrate, respectively. In addition, this technique resolves other anions that are present in neuronal tissues at sub-nanomolar concentrations and can be broadly applied for high-throughput anionic profiling. In rat dorsal root ganglia, endogenous levels of nitrate (231+/-29 microM; n=6) and nitrite (24-96 microM) were found. These concentrations exceeded those previously found in neuronal tissue homogenates using different techniques. PMID:12052727

Boudko, Dmitri Y; Cooper, Brian Y; Harvey, William R; Moroz, Leonid L

2002-07-01

193

Acute toxicity of nitrite and ammonia to Daphnia similoides of different developmental stages: using the modified Gaussian model to describe.  

PubMed

To gain an insight into the tolerance of Daphnia to nitrite and ammonia, a modified Gaussian model was used to describe the trends of changes in LC50s of nitrite and ammonia to Daphnia similoides at different developmental stages. LC50s of NO(2)-N and NH(3)-N increased with age before maturation and then decreased at maturation. A modified Gaussian model provided an accurate fit for the changes in LC50s of NO(2)-N and NH(3)-N, in which the parameters have definite biological meanings. From this model, we can gain an insight into the maximum LC50 and the age that has the maximum LC50 and predict LC50s at any specific ages. We suggest that such a model might be used to describe the trend in acute toxicity of some other zooplankton species at different stages. PMID:20431865

Xiang, Fuhui; Yang, Wei; Chen, Yafen; Yang, Zhou

2010-04-30

194

Simultaneous electrochemical determination of nitrate and nitrite in aqueous solution using Ag-doped zeolite-expanded graphite-epoxy electrode.  

PubMed

In this work a new electrochemical sensor based on an Ag-doped zeolite-expanded graphite-epoxy composite electrode (AgZEGE) was evaluated as a novel alternative for the simultaneous quantitative determination of nitrate and nitrite in aqueous solutions. Cyclic voltammetry was used to characterize the electrochemical behavior of the electrode in the presence of individual or mixtures of nitrate and nitrite anions in 0.1M Na(2)SO(4) supporting electrolyte. Linear dependences of current versus nitrate and nitrite concentrations were obtained for the concentration ranges of 1-10mM for nitrate and 0.1-1mM for nitrite using cyclic voltammetry (CV), chronoamperometry (CA), and multiple-pulsed amperometry (MPA) procedures. The comparative assessment of the electrochemical behavior of the individual anions and mixtures of anions on this modified electrode allowed determining the working conditions for the simultaneous detection of the nitrite and nitrate anions. Applying MPA allowed enhancement of the sensitivity for direct and indirect nitrate detection and also for nitrite detection. The proposed sensor was applied in tap water samples spiked with known nitrate and nitrite concentrations and the results were in agreement with those obtained by a comparative spectrophotometric method. This work demonstrates that using multiple-pulse amperometry with the Ag-doped zeolite-expanded graphite-epoxy composite electrode provides a real opportunity for the simultaneous detection of nitrite and nitrate in aqueous solutions. PMID:21035645

Manea, Florica; Remes, Adriana; Radovan, Ciprian; Pode, Rodica; Picken, Stephen; Schoonman, Joop

2010-09-20

195

Sulfide-induced dissimilatory nitrate reduction to ammonia in anaerobic freshwater sediments  

Microsoft Academic Search

Different reduced sulfur compounds (H2S, FeS, S2O32?) were tested as electron donors for dissimilatory nitrate reduction in nitrate-amended sediment slurries. Only in the free sulfide-enriched slurries was nitrate appreciably reduced to ammonia (0.30 ?mol NH4+?mol NO3?), with concomitant oxidation of sulfide to S0 (0.55 ?mol S0?mol S2?). The initial concentration of free sulfide appears as a factor determining the type

R. C. Brunet; L. J. Garcia-Gil

1996-01-01

196

Determination of nitrate and nitrite in Hanford defense waste(HDW) by reverse polarity capillary zone electrophoresis (RPCE)method  

SciTech Connect

This paper describes the first application of reverse polarity capillary zone electrophoresis (RPCE) for rapid and accurate determination of nitrate and nitrite in Hanford Defense Waste (HDW). The method development was carried out by using Synthetic Hanford Waste (SHW), followed by the analysis of 4 real HDW samples. Hexamethonium bromide (HMB) was used as electroosmotic flow modifier in borate buffer at pH 9.2 to decrease the electroosmotic flow (EOF) in order to enhance the speed of analysis and the resolution of nitrate and nitrite in high ionic strength HDW samples. The application of this capillary zone electrophoresis method, when compared with ion chromatography for two major components of HDW, nitrate and nitrite slightly reduced analysis time, eliminated most pre-analysis handling of the highly radioactive sample, and cut analysis wastes by more than 2 orders of magnitude. The analysis of real HDW samples that were validated by using sample spikes showed a concentration range of 1.03 to 1.42 M for both nitrate. The migration times of the real HDW and the spiked HDW samples were within a precision of less than 3% relative standard deviation. The selectivity ratio test used for peak confirmation of the spiked samples was within 96% of the real sample. Method reliability was tested by spiking the matrix with 72.4 mM nitrate and nitrite. Recoveries for these spiked samples were 93-103%.

Metcalf, S.G.

1998-06-10

197

Ammonia- and Nitrite-Oxidizing Bacterial Communities in a Pilot-Scale Chloraminated Drinking Water Distribution System  

PubMed Central

Nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. The diversity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (T-RFLP) analysis and 16S rRNA gene (ribosomal DNA [rDNA]) cloning and sequencing. For ammonia oxidizers, 16S rDNA-targeted T-RFLP indicated the presence of Nitrosomonas in each of the distribution systems, with a considerably smaller peak attributable to Nitrosospira-like AOB. Sequences of AOB amplification products aligned within the Nitrosomonas oligotropha cluster and were closely related to N. oligotropha and Nitrosomonas ureae. The nitrite-oxidizing communities were comprised primarily of Nitrospira, although Nitrobacter was detected in some samples. These results suggest a possible selection of AOB related to N. oligotropha and N. ureae in chloraminated systems and demonstrate the presence of NOB, indicating a biological mechanism for nitrite loss that contributes to a reduction in nitrite-associated chloramine decay.

Regan, John M.; Harrington, Gregory W.; Noguera, Daniel R.

2002-01-01

198

Sodium nitrite and potassium nitrate in control of nonproteolytic Clostridium botulinum outgrowth and toxigenesis in vacuum-packed cold-smoked rainbow trout  

Microsoft Academic Search

The effect of sodium nitrite (NaNO2) and potassium nitrate (KNO3) on the outgrowth and toxigenesis of nonproteolytic Clostridium botulinum in vacuum-packed cold-smoked rainbow trout stored for six weeks was studied in two inoculation studies at slightly abusive storage temperatures of 4 °C and 8 °C. The depletion rate of nitrite and the reduction rate of nitrate to nitrite as well

Eija Hyytiä; Susanna Eerola; Sebastian Hielm; Hannu Korkeala

1997-01-01

199

Induction of nitrate reductase, nitrite reductase, and glutamine synthetase isoforms in sunflower cotyledons as affected by nitrate, light, and plastid integrity  

Microsoft Academic Search

Summary We investigated the inducibility of nitrate reductase (NR; EC 1.6.6.1), nitrite reductase (NiR; EC 1.7.7.1), and glutamine synthetase (GS; EC 6.3.1.2) isoforms in cotyledons of 7-day-old seedlings of sunflower (Helianthus annuus L.) in relation to light, nitrogen source (NO3-, NO2- or NH4+), and the involvement of plastids. Nitrate was absolutely (and specifically) required for NR induction, and stimulated more

P. Cabello; P. de la Haba; A. González-Fontes; J. M. Maldonado

1998-01-01

200

Epithelial ovarian cancer and exposure to dietary nitrate and nitrite in the NIH-AARP Diet and Health Study.  

PubMed

Ovarian cancer is a leading cause of cancer death among women in the United States and it has the highest mortality rate of all gynecologic cancers. Internationally, there is a five-fold variation in incidence and mortality of ovarian cancer, which suggests a role for environmental factors, including diet. Nitrate and nitrite are found in various food items and they are precursors of N-nitroso compounds, which are known carcinogens in animal models. We evaluated dietary nitrate and nitrite intake and epithelial ovarian cancer in the National Institutes of Health (NIH)-AARP Diet and Health Study, including 151 316 women aged 50-71 years at the time of the baseline questionnaire in 1995-1996. The nitrate and nitrite intake was assessed using a 124-item validated food frequency questionnaire. Through 31 December 2006, 709 incident epithelial ovarian cancer cases with complete dietary information were identified. Using Cox proportional hazards regression to estimate hazard ratios and 95% confidence intervals (CIs), women in the highest intake quintile of dietary nitrate had a 31% increased risk (95% CI: 1.01-1.68) of epithelial ovarian cancer, compared with those in the lowest intake quintile. Although there was no association for total dietary nitrite, those in the highest intake category of animal sources of nitrite had a 34% increased risk (95% CI: 1.05-1.69) of ovarian cancer. There were no clear differences in risk by histologic subtype of ovarian cancer. Our findings suggest that a role of dietary nitrate and nitrite in ovarian cancer risk should be followed in other large cohort studies. PMID:21934624

Aschebrook-Kilfoy, Briseis; Ward, Mary H; Gierach, Gretchen L; Schatzkin, Arthur; Hollenbeck, Albert R; Sinha, Rashmi; Cross, Amanda J

2012-01-01

201

[Excretion of nitrates with saliva and urine and nitrite excretion with saliva in patients with chronic gastritis and duodenal ulcer].  

PubMed

The study assessed excretion of nitrates in urine and saliva and that of nitrites with saliva of patients suffering gastric and duodenal ulcer. In both study groups, a positive correlation was established between nitrate concentration in saliva, on the one hand, and that in urine, and nitrite level in urine, on the other. The groups failed to show a difference in nitrate concentrations in either urine or saliva. Since retention of nitrates in the body of chronic gastritis patients held as precancer of the stomach proved no higher than that in patients with duodenal ulcer, the authors cast doubt on endogenous nitroso compounds as a cause of gastric cancer in cases of chronic gastritis. PMID:1887643

Rooma, M Ia; Khe?nla, Iu Ia; Piarn, Kh M; Kann, E M

1991-01-01

202

The Effect of Exogenous IAA and Kinetin on Nitrate Reductase, Nitrite Reductase and Glutamate Dehydrogenase Activities in Excised Pea Roots  

Microsoft Academic Search

Nitrate reductase (NO3R) activity, nitrite reductase (NO2R) activity and NADH2 dependent glutamate dehydrogenase (GDH) activity were followed in extracts from excised pea roots incubated under aseptic\\u000a conditions for 9 and 24 h in nitrate containing nutrient medium to which IAA was added in concentrations promoting lateral\\u000a root formation (1 × 10?5; 3 × 10?5; 5 × 10?5 M) and kinetin

J. Sahulka

1972-01-01

203

Nitrates, nitrites and N?nitrosocompounds: A review of the occurrence in food and diet and the toxicological implications  

Microsoft Academic Search

Data on occurrence of nitrate, nitrite and N?nitrosocompounds in food and drinking water, and on total dietary intakes are reviewed. Metabolic, toxicological and epidemiological studies are surveyed and the implications with respect to safety evaluation are addressed. It is concluded that, on the basis of recent long?term animal studies and of clinical experience in man, the current Acceptable Daily Intake

R. Walker

1990-01-01

204

Determination of nitrates, nitrites and oxalates in food products by capillary electrophoresis with pH-dependent electroosmotic flow reversal  

Microsoft Academic Search

This paper describes an innovative and rapid capillary electrophoretic method for the simultaneous analysis of nitrates, nitrites and oxalates, which are anions of food interest. The novelty of our method is based on reversing the electroosmotic flow without using any buffer additive nor performing a capillary coating, but simply employing a buffer at low pH values.The analytical conditions have been

Cristiana Merusi; Claudio Corradini; Antonella Cavazza; Chiara Borromei; Paola Salvadeo

2010-01-01

205

Lipid Peroxidation and Nitrite plus Nitrate Levels in Brain Tissue from Patients with Alzheimer’s Disease  

Microsoft Academic Search

Background: Although oxidative stress has been implicated in the pathogenesis of neurodegenerative diseases, data found in the literature are still a matter of controversy. Objective: To study lipid peroxidation and nitrite plus nitrate levels in brain specimens (frontal, parietal, temporal, and occipital cortices) from 8 patients with Alzheimer’s disease (AD) in comparison to 6 young and 7 age-matched controls. Methods:

Maira DiCiero Miranda; Veralice M. S. de Bruin; Marcus R. Vale; Glauce S. B. Viana

2000-01-01

206

Geographic Distribution of Liver and Stomach Cancers in Thailand in Relation to Estimated Dietary Intake of Nitrate, Nitrite, and Nitrosodimethylamine  

Microsoft Academic Search

It is our working hypothesis that the high rate of the liver and gastric cancers in North and Northeast Thailand is associated with increased daily dietary intake of nitrate, nitrite, and nitrosodimethylamine (NDMA). Samples of fresh and preserved Thai foods were systematically collected and analyzed from 1988 to 1996 and from 1998 to 2005. Consumption frequencies of various food items

Eugene J. Mitacek; Klaus D. Brunnemann; Maitree Suttajit; Lee S. Caplan; Claude E. Gagna; Kris Bhothisuwan; Sirithon Siriamornpun; Charles F. Hummel; Hiroshi Ohshima; Ranja Roy; Nimit Martin

2008-01-01

207

Effect of temperature and free ammonia on nitrification and nitrite accumulation in landfill leachate and analysis of its nitrifying bacterial community by FISH  

Microsoft Academic Search

The cause of seasonal failure of a nitrifying municipal landfill leachate treatment plant utilizing a fixed biofilm was investigated by wastewater analyses and batch respirometric tests at every treatment stage. Nitrification of the leachate treatment plant was severely affected by the seasonal temperature variation. High free ammonia (NH3-N) inhibited not only nitrite oxidizing bacteria (NOB) but also ammonia oxidizing bacteria

Dong-Jin Kim; Dong-Ig Lee; Jürg Keller

2006-01-01

208

Single-step nitrification models erroneously describe batch ammonia oxidation profiles when nitrite oxidation becomes rate limiting  

Microsoft Academic Search

Nitrification involves the sequential biological oxidation of reduced nitrogen species such as ammo- nium-nitrogen (NH4 + -N) to nitrite-nitrogen (NO2 ? -N) and nitrate-nitrogen (NO3 ? -N). The adequacy of modeling NH4 + -N to NO3 ? -N oxidation as one composite biochemi- cal reaction was examined at different relative dynamics of NH4 + -N to NO2 ? -N and

Kartik Chandran; Barth F. Smets

2000-01-01

209

Low disturbance manure incorporation effects on ammonia and nitrate losses  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ammonia volatilization represents a major mechanism of nitrogen (N) loss from land-applied manure and is an air quality concern. A field study was conducted to assess ammonia emissions related to manure application method in central Pennsylvania on a Hagerstown soil (Fine, mixed semiactive, mesic Ty...

210

Analysis of nitrate and nitrite in water and urine by capillary zone electrophoresis.  

PubMed

A capillary zone electrophoresis method for the separation and analysis of nitrate and nitrite in water and urine was developed. No interference in the electropherogram from other anions is observed by using a polyacrylamide-coated column with a modified phosphate buffer at pH 3 for the separation, and UV absorption at 214 nm for the detection. The method does not require sample pretreatment or the use of organic solvents. The limit of detection for each analyte (S/N = 3), using a 75 microns I.D. capillary, is 0.5 microgram/ml. Urine samples require 40-fold dilution in order to maintain migration time reproducibility to within 1% relative standard deviation. PMID:7952107

Janini, G M; Chan, K C; Muschik, G M; Issaq, H J

1994-07-15

211

Formation of zinc protoporphyrin IX in Parma-like ham without nitrate or nitrite.  

PubMed

Zinc protoporphyrin IX (ZPP) is a characteristic red pigment in meat products that are manufactured without the addition of a curing agent such as nitrate or nitrite. To examine the effects of impurities such as mineral components in sea salt on the formation of ZPP, we manufactured Parmatype dry-cured hams that were salted with refined salt or sea salt and examined the involvement of oxidation-reduction potential (ORP) in the formation of ZPP. The content of ZPP was increased drastically after 40 weeks. Microscopic observation showed strong fluorescence caused by ZPP muscle fiber after 40 weeks. Conversely, heme content varied considerably during processing. ORP increased during processing. However, there was no obvious difference between ham salted with refined salt and that salted with sea salt. Therefore, it was concluded that impurities in sea salt were not involved in the formation of ZPP. PMID:20163591

Wakamatsu, Jun-ichi; Uemura, Juichi; Odagiri, Hiroko; Okui, Jun; Hayashi, Nobutaka; Hioki, Shoji; Nishimura, Takanori; Hattori, Akihito

2009-04-01

212

Effects of nitrate and nitrite on dissimilatory iron reduction by Shewanella putrefaciens 200.  

PubMed Central

The inhibitory effects of nitrate (NO3-) and nitrite (NO2-) on dissimilatory iron (FE3+) reduction were examined in a series of electron acceptor competition experiments using Shewanella putrefaciens 200 as a model iron-reducing microorganism. S. putrefaciens 200 was found to express low-rate nitrate reductase, nitrite reductase, and ferrireductase activity after growth under highly aerobic conditions and greatly elevated rates of each reductase activity after growth under microaerobic conditions. The effects of NO3- and NO2- on the Fe3+ reduction activity of both aerobically and microaerobically grown cells appeared to follow a consistent pattern; in the presence of Fe3+ and either NO3- or NO2-, dissimilatory Fe3+ and nitrogen oxide reduction occurred simultaneously. Nitrogen oxide reduction was not affected by the presence of Fe3+, suggesting that S. putrefaciens 200 expressed a set of at least three physiologically distinct terminal reductases that served as electron donors to NO3-, NO2-, and Fe3+. However, Fe3+ reduction was partially inhibited by the presence of either NO3- or NO2-. An in situ ferrozine assay was used to distinguish the biological and chemical components of the observed inhibitory effects. Rate data indicated that neither NO3- nor NO2- acted as a chemical oxidant of bacterially produced Fe2+. In addition, the decrease in Fe3+ reduction activity observed in the presence of both NO3- and NO2- was identical to the decrease observed in the presence of NO2- alone. These results suggest that bacterially produced NO2- is responsible for inhibiting electron transport to Fe3+.

DiChristina, T J

1992-01-01

213

Prospective study of meat intake and dietary nitrates, nitrites, and nitrosamines and risk of adult glioma123  

PubMed Central

Background: The hypothesis that nitrosamine exposure may increase the risk of glioma has been circulating for several decades, but testing it has been difficult because of the ubiquitous nature of nitrosamine exposure. Diet has been the focus of many studies because it can substantially influence nitrosamine exposure, mostly from the endogenous formation of nitrosamines based on intake of nitrite and nitrate. Objective: The objective was to examine the relation between intakes of meats, nitrate, nitrite, and 2 nitrosamines [nitrosodimethylamine (NDMA) and nitrosopyrolidine (NPYR)] and glioma risk in a prospective analysis. Methods: Data from 3 US prospective cohort studies were combined for this analysis; 335 glioma cases were diagnosed during ?24 y of follow-up. Dietary intake was assessed with food-frequency questionnaires. Nitrate, nitrite, and nitrosamine values were calculated based on published values of these nutrients in various foods over different periods in time. Cox proportional hazards models were used to estimate incidence rate ratios (RRs) and 95% CIs. Estimates from each cohort were pooled by using a random-effects model. Results: Risk of glioma was not elevated among individuals in the highest intake category of total processed meats (RR: 0.92; 95% CI: 0.48, 1.77), nitrate (RR: 1.02; 95% CI: 0.66, 1.58), nitrites (RR: 1.26; 95% CI: 0.89, 1.79), or NDMA (RR: 0.88; 95% CI: 0.57, 1.36) compared with the lowest category. No effect modification was observed by intake of vitamins C or E or other antioxidant measures. Conclusion: We found no suggestion that intake of meat, nitrate, nitrite, or nitrosamines is related to the risk of glioma.

Holick, Crystal N; Batchelor, Tracy T; Giovannucci, Edward; Hunter, David J

2009-01-01

214

Effects of pH, phosphate and ammonia on the rate of uptake of nitrate and ammonia by freshwater phytoplankton  

Microsoft Academic Search

The effect of phosphate (PO4+3) and pH in regulating nitrate (NO3) and ammonia (NH3+) uptake by phytoplankton was investigated in two Oklahoma lakes using 15N tracers. Addition of PO4+3 above ambient concentrations had a negligible effect on the rate of uptake of NO3- or NH3+. Manipulation of pH of lake water had little effect on uptake of either NO3- or

Dale W. Toetz

1981-01-01

215

Copper, zinc superoxide dismutase and nitrate reductase coimmobilized bienzymatic biosensor for the simultaneous determination of nitrite and nitrate.  

PubMed

This work presents a novel bienzymatic biosensor for the simultaneous determination of nitrite (NO2(-)) and nitrate (NO3(-)) ions using copper, zinc superoxide dismutase (SOD1) and nitrate reductase (NaR) coimmobilized on carbon nanotubes (CNT)-polypyrrole (PPy) nanocomposite modified platinum electrode. Morphological changes of the PPy and CNT modified electrodes were investigated using scanning electron microscopy. The electrochemical behavior of the bienzymatic electrode (NaR-SOD1-CNT-PPy-Pt) was characterized by cyclic voltammetry exhibiting quasi-reversible redox peak at +0.06V and reversible redox peaks at -0.76 and -0.62V vs. Ag/AgCl, for the immobilized SOD1 and NaR respectively. The electrocatalytic activity of SOD1 towards NO2(-) oxidation observed at +0.8V was linear from 100nM to 1mM with a detection limit of 50nM and sensitivity of 98.5±1.7nAµM(-1)cm(-2). Similarly, the coimmobilized NaR showed its electrocatalytic activity towards NO3(-) reduction at -0.76V exhibiting linear response from 500nM to 10mM NO3(-) with a detection limit of 200nM and sensitivity of 84.5±1.56nAµM(-1)cm(-2). Further, the present bienzymatic biosensor coated with cellulose acetate membrane for the removal of non-specific proteins was used for the sensitive and selective determinations of NO2(-) and NO3(-) present in human plasma, whole blood and saliva samples. PMID:24055935

Madasamy, Thangamuthu; Pandiaraj, Manickam; Balamurugan, Murugesan; Bhargava, Kalpana; Sethy, Niroj Kumar; Karunakaran, Chandran

2013-08-28

216

21 CFR 181.34 - Sodium nitrite and potassium nitrite.  

Code of Federal Regulations, 2010 CFR

...Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium nitrite are subject to prior sanctions...preservative agents, with or without sodium or potassium nitrate, in the curing of red meat and...

2010-01-01

217

21 CFR 181.34 - Sodium nitrite and potassium nitrite.  

Code of Federal Regulations, 2010 CFR

...Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium nitrite are subject to prior sanctions...preservative agents, with or without sodium or potassium nitrate, in the curing of red meat and...

2009-04-01

218

DXRD studies of sodium nickel ferrocyanide reactions with equimolar nitrate/nitrite salts  

SciTech Connect

Dynamic X-ray diffraction (DXRD) has been used to identify and quantify the solid-state reactions that take place between sodium nickel ferrocyanide, Na[sub 2]NiFe(CN)[sub 6], and equimolar concentrations of sodium nitrate/nitrite, reactions of interest to the continued environmental safety of certain waste storage tanks at the Hanford site in eastern Washington. The results are supportive of previous work that indicated that endothermic dehydration and melting of the nitrates take place prior to the occurrence of exothermic reactions, which begin about 300[degree]C. The DXRD results show that a major reaction set at these temperatures is the occurrence of a series reaction which produces sodium cyanate, NaCNO, as an intermediate in a mildly exothermic first step. In the presence of gaseous oxygen, NaCNO subsequently reacts exothermally and at a faster rate to form metal oxides. Measurements of the rate of this reaction are used to estimate the heat release, and comparisons of this with heat-transfer rates from a hypothetical [open quotes]hot spot[close quotes] show that, even in a worse case scenario, the heat-transfer rates are approximately eight times higher than the rate of energy release from the exothermic reactions. 20 refs., 7 figs., 3 tabs.

Dodds, J.N.; Thomson, W.J. (Washington State Univ., Pullman, WA (United States))

1994-05-01

219

The genes YNI1 and YNR1, encoding nitrite reductase and nitrate reductase respectively in the yeast Hansenula polymorpha, are clustered and co-ordinately regulated.  

PubMed Central

The nitrite reductase-encoding gene (YNI1) from the yeast Hansenula polymorpha was isolated from a lambda EMBL3 H. polymorpha genomic DNA library, using as a probe a 481 bp DNA fragment from the gene of Aspergillus nidulans encoding nitrite reductase (niiA). An open reading frame of 3132 bp, encoding a putative protein of 1044 amino acids with high similarity with nitrite reductases from fungi, was located by DNA sequencing in the phages lambdaNB5 and lambdaJA13. Genes YNI1 and YNR1 (encoding nitrate reductase) are clustered, separated by 1700 bp. Northern blot analysis showed that expression of YNI1 and YNR1 is co-ordinately regulated; induced by nitrate and nitrite and repressed by sources of reduced nitrogen, even in the presence of nitrate. A mutant lacking nitrite reductase activity was obtained by deletion of the chromosomal copy of YNI1. The mutant does not grow in nitrate or in nitrite; it exhibits a similar level of transcription of YNR1 to the wild type, but the nitrate reductase enzymic activity is only about 50% of the wild type. In the presence of nitrate the delta ynil::URA3 mutant extrudes approx. 24 nmol of nitrite/h per mg of yeast (wet weight), about five times more than the wild type.

Brito, N; Avila, J; Perez, M D; Gonzalez, C; Siverio, J M

1996-01-01

220

An automatic gas-phase molecular absorption spectrometric system using a UV-LED photodiode based detector for determination of nitrite and total nitrate.  

PubMed

An automatic gas-phase molecular absorption spectrometric (GPMAS) system was developed and applied to determine nitrite and total nitrate in water samples. The GPMAS system was coupled with a UV-light emitting diode photodiode (UV-LED-PD) based photometric detector, including a 255 nm UV-LED as the light source, a polyvinyl chloride (PVC) tube of 14 cm as the gas flow cell, and an integrated photodiode amplifier to measure the transmitted light intensity. The UV-LED-PD detector was compact, robust, simple and of low heat production, comparing with detectors used in other GPMAS works. For nitrite measurement, citric acid was used to acidify the sample, and ethanol to catalyze the quantitative formation of NO(2). The produced NO(2) was purged with air flow into the UV-LED-PD detector, and the gaseous absorbance value was measured. The total nitrate could be determined after being reduced to nitrite with a cadmium column. Limits of detection for nitrite and nitrate were 7 ?mol/L and 12 ?mol/L, respectively; and linear ranges of 0.021-5 mmol/L for nitrite and 0.036-4 mmol/L for nitrate were obtained. Related standard deviations were 1.81% and 1.08% for nitrite and nitrate, respectively, both at 2 mmol/L. The proposed method has been applied to determine nitrite and total nitrate in some environmental water samples. PMID:21376971

Zhang, Min; Zhang, Zhen; Yuan, Dongxing; Feng, Sichao; Liu, Baomin

2011-01-26

221

Accumulation of Nitrate and Nitrite in Chilled Leaves of Rice Seedlings is Induced by High Root Temperature.  

PubMed

We previously found a novel type of chilling injury in the leaves of rice seedlings (Oryza sativa L. cv. Akitakomachi). The damage was only observed when the roots were not chilled (10°C/25°C, shoots/roots), but not when the whole seedling was chilled (10°C/10°C). In this report, we show that the chilling injury induced by high root temperature required nitrate and potassium together with a trace amount of iron, manganese or both in the nutrient solution during the treatment, and that the injury was increased by nitrogen starvation before chilling. Both nitrate and nitrite accumulated in the 10°C/25°C leaves when the nutrient solution contained nitrate. The nitrate accumulation in the 10°C/25°C leaves was highest at the end of the first light period, and was followed by a decrease with a concomitant increase in nitrite during the first dark period. The photosynthetic electron transport was completely lost in both PSII and PSI in the 10°C/25°C leaves when the nutrient solution contained nitrate. However, the activities in the leaves of the 10°C/25°C plants treated with the nutrient solution lacking nitrate remained at approximately half those in the 10°C/10°C leaves. The photochemical quenching of Chl fluorescence and the P700 oxidation state were also intermediate between those in the 10°C/25°C and 10°C/10°C leaves of plants supplied with the complete nutrients. Thus, the chilling injury was closely linked to the accumulation of nitrate and nitrite, as well as to a malfunction of photosynthesis in the 10°C/25°C leaves. PMID:23975886

Suzuki, Kensaku; Ohmori, Yukimi; Nagao, Manabu

2013-08-23

222

STUDY ON THE PRECIPITATION OF AMMONIUM URANATES. I. REACTION BETWEEN URANYL NITRATE AND AMMONIA  

Microsoft Academic Search

The mechanism of the precipitation and the composition of the ; precipitate which results from the reaction between uranyl nitrate and ammonia ; were studied by potentiometric, conductometric, and analytical methods. It is ; shown that the ammonium diuranate is not obtained as has been reponted in the ; literature. At the beginning a precipitate with the compoisition (NHâ)\\/sub ;

C. Dragulescu; I. Julean

1959-01-01

223

Simultaneous Determination of Nitrate and Nitrite in Natural Water and Waste Water from Uranium Mines with Dual-Wavelength Spectrophotometric Method.  

National Technical Information Service (NTIS)

A new method is described for the simultaneous direct determination of nitrate and nitrite in natural water and waste water from uranium mines with dual-wavelength spectrophotometric method. The measuring wavelength and the referential wavelength are 219 ...

W. Jin Z. Yin M. Yao

1987-01-01

224

Hydrogen peroxide-dependent conversion of nitrite to nitrate as a crucial feature of bovine milk catalase.  

PubMed

The enzyme catalase is well-known to catalyze the disintegration of hydrogen peroxide to water and oxygen; however, this study shows that its main function in bovine milk is oxidation of nitrite to nitrate. This process depends on hydrogen peroxide, of which the main source appears to be hydrogen peroxide formation that is coupled to the conversion of purines--xanthine in the present study--to uric acid by milk xanthine oxidase. However, additional secondary sources of hydrogen peroxide appear to be important during the relatively long storage of milk in the gland cistern. This paper demonstrates that the oxidation of nitrite to nitrate is necessary to prevent accumulation of free radicals and oxidative products during storage of milk in the gland and during the unavoidable delay between milking and pasteurization in dairy plants. Recommendations for minimizing the deterioration in milk quality during commercial storage are presented. PMID:19722711

Silanikove, Nissim; Shapiro, Fira; Silanikove, Mayan; Merin, Uzi; Leitner, Gabriel

2009-09-01

225

A simple and accurate method to determine nitrite and nitrate in serum based on high-performance liquid chromatography with fluorescence detection.  

PubMed

A simple method for accurate determination of nitrite and nitrate in serum was proposed to avoid the variation of nitrate reduction. For nitrite determination, serum samples were directly precipitated with methanol pre-nitrate conversion, and then the supernatant reacted with 2,3-diaminonaphthalene (DAN) to form 2,3-naphthotriazole (NAT), which was quantitatively analyzed by high-performance liquid chromatography coupled with fluorescence detection (HPLC-FL). For nitrate determination, samples were firstly heated at 70°C for 10 min to inactivate endogenous reductase-inhibiting proteins, then nitrate in the samples was quantitatively reduced to nitrite by reductase added experimentally. The difference in total nitrite concentrations between pre- and post-nitrate conversion was used to calculate the amount of nitrate in the samples. In addition to good specificity, high sensitivity, satisfactory accuracy and reproducibility, our method is simple and suitable for the quantitative determination of nanomolar level of nitrite and nitrate in a large number of serum samples. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23760922

Shu-Yu, Zhan; Qing, Shao; Li, Liu; Xiao-Hui, Fan

2013-06-13

226

Reactions of nitrate and nitrite in foods with special reference to the determination of N?nitroso compounds  

Microsoft Academic Search

The stabilities of nitrate and nitrite in food systems and their reactions in such matrices are reviewed. Particular reference is made to reactions with haem proteins, smoke components and amines in foods, and the chemistry of formation ofN?nitroso compounds from food components is discussed. Finally, the methodology available for determination of both volatile and non?volatile N?nitroso compounds is addressed.

C. L. Walters

1992-01-01

227

Quantification of Nitrite\\/Nitrate in Food Stuff Samples Using 2-Aminobenzoic Acid as a New Amine in Diazocoupling Reaction  

Microsoft Academic Search

2-Aminobenzoic acid has been used as an amine in diazocoupling reaction to form an azo dye in the quantification of nitrite\\/nitrate\\u000a at trace level. The formed azo dye has an absorption maximum at 550 nm in aqueous phase, and the resulted dye can be extracted\\u000a into organic solvent to lower the detection limit. The method obeys Beer's law in the concentration

Malingappa Pandurangappa; Yarradoddappa Venkataramanappa

2011-01-01

228

Quantum Yields for OH Formation from the Photolysis of Nitrite on Ice: Comparison to Nitrate and Hydrogen Peroxide  

NASA Astrophysics Data System (ADS)

The photodecomposition of nitrate, nitrite, and hydrogen peroxide generates hydroxyl radicals (OH) in ice and snow. These photoreactive species can affect snow chemistry as well as ice-core records and the atmospheric boundary layer. For example, it has been hypothesized that photoformed OH can oxidize organic carbon in the snowpack and lead to the release of volatile organic compounds such as formaldehyde. While the quantum yields of OH radicals from the photolysis of nitrate and hydrogen peroxide in ice have been measured,[1-3] the photochemical behavior of nitrite in ice and snow remains an open issue. In this study, we are measuring the quantum yields of the OH radical (? (NO2- --> OH)) from the photolysis of frozen aqueous NO2- solutions using benzoate as a chemical probe. For this presentation we will discuss: (1) NO2- molar absorptivities; (2) The temperature dependence of (? (NO2- --> OH)) for ice pellets at temperatures between 243 K and 268 K, and (3) The pH dependence of (? (NO2- --> OH)) and the relative reactivities of NO2- and HNO2 at 263 K. We will also compare the nitrite results with those previously determined for nitrate and hydrogen peroxide, including the relative contributions for OH formation from nitrate, nitrite, and hydrogen peroxide in the snow, and the atmospheric implications of these reactions. References: 1. Dubowski, Y.; Colussi, A. J.; Hoffmann, M. R. J.Phys.Chem.A 2001, 105, 4928. 2. Chu, L.; Anastasio, C. J.Phys.Chem.A 2003, 107, 9594. 3. Chu, L.; Anastasio, C. Quantum Yields of OH from the Photolysis of Hydrogen Peroxide in Ice, in preparation.

Chu, L.; Anastasio, C.

2004-12-01

229

Ferrocyanide Safety Project Dynamic X-Ray Diffraction studies of sodium nickel ferrocyanide reactions with equimolar nitrate\\/nitrite salts  

Microsoft Academic Search

Dynamic X-ray Diffraction (DXRD) has been to used to identify and quantify the solid state reactions that take place between sodium nickel ferrocyanide, NaâNiFe(CN)â, and equimolar concentrations of sodium nitrate\\/nitrite, reactions of interest to the continued environmental safety of several large underground waste storage tanks at the Hanford site in eastern Washington. The results are supportive of previous work, which

Dodds

1994-01-01

230

Fine structure characterization of zero-valent iron nanoparticles for decontamination of nitrites and nitrates in wastewater and groundwater  

Microsoft Academic Search

The main objectives of the present study were to investigate the chemical reduction of nitrate or nitrite species by zero-valent iron nanoparticle (ZVIN) in aqueous solution and related reaction kinetics or mechanisms using fine structure characterization. This work also exemplifies the utilization of field emission-scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD) to reveal the speciation

Kuen-Song Lin; Ni-Bin Chang; Tien-Deng Chuang

2008-01-01

231

Intracellular Conversion of Environmental Nitrate and Nitrite to Nitric Oxide with Resulting Developmental Toxicity to the Crustacean Daphnia magna  

Microsoft Academic Search

BackgroundNitrate and nitrite (jointly referred to herein as NOx) are ubiquitous environmental contaminants to which aquatic organisms are at particularly high risk of exposure. We tested the hypothesis that NOx undergo intracellular conversion to the potent signaling molecule nitric oxide resulting in the disruption of endocrine-regulated processes.Methodology\\/Principal FindingsThese experiments were performed with insect cells (Drosophila S2) and whole organisms Daphnia

Bethany R. Hannas; Parikshit C. Das; Hong Li; Gerald A. LeBlanc

2010-01-01

232

SHORT REPORT: TOTAL SERUM LEVELS OF THE NITRIC OXIDE DERIVATIVES NITRITE\\/NITRATE DURING MICROFILARIAL CLEARANCE IN HUMAN FILARIAL DISEASE  

Microsoft Academic Search

Nitric oxide (NO) has recently been shown to be cytotoxic to both microfilariae and adultBrugia malayi in vitro and in a murine model, as well against Onchocerca lienalis microfilariae in vitro. We studied the kinetics of nitrite\\/nitrate, both stable end products of NO, by high-pressure liquid chromatography during microfilaricidal che- motherapy in four filariasis (three Loa loa, and one Onchocerca

STEFAN WINKLER; IBRAHIM EL MENYAWI; KEN FLORIS LINNAU; WOLFGANG GRANINGER

233

Formation of vascular S-nitrosothiols and plasma nitrates/nitrites following inhalation of diesel emissions.  

PubMed

Epidemiological studies have associated traffic-related airborne pollution with adverse cardiovascular outcomes. Nitric oxide (NO) is a common component of fresh diesel and gasoline engine emissions that rapidly transforms both in the atmosphere and once inhaled. Because of this rapid transformation, limited information is available in terms of potential human exposures and adverse health effects. Young rats were exposed to whole diesel emissions (DE) adjusted to 300 ?g/m(3) of particulate matter (containing 3.5 ppm NO) or 0, 3, or 10 ppm NO as a positive control. Animals were also pre-injected (ip) with either saline or N-acetylcysteine (NAC), a precursor of glutathione. Predictably, pure NO exposures led to a concentration-dependent increase in plasma nitrates compared to controls, which lasted for roughly 4 h postexposure. Whole DE exposure for 1 h also led to a doubling of plasma NOx. NAC injection increased the levels of plasma nitrates and nitrites (NOx) in the DE exposure group. Inhibition of nitric oxide symthase (NOS) by N(G)-nitro-L-arginine (L-NNA) did not block the rise in plasma NOx, demonstrating that the increase was entirely due to exogenous sources. Both DE and pure NO exposures paradoxically led to elevated eNOS expression in aortic tissue. Furthermore, coronary arterioles from NO-exposed animals exhibited greater constriction to endothelin-1 compared to controls, consistent with a derangement of the NOS system. Thus, NO may be an important contributor to traffic-related cardiovascular morbidity, although further research is necessary for proper hazard identification. PMID:21598168

Knuckles, Travis L; Buntz, Jennifer G; Paffett, Michael; Channell, Meghan; Harmon, Molly; Cherng, Tom; Lucas, Selita N; McDonald, Jacob D; Kanagy, Nancy L; Campen, Matthew J

2011-01-01

234

Formation of Vascular S-Nitrosothiols and Plasma Nitrates/Nitrites Following Inhalation of Diesel Emissions  

PubMed Central

Epidemiological studies have associated traffic-related airborne pollution with adverse cardiovascular outcomes. Nitric oxide (NO) is a common component of fresh diesel and gasoline engine emissions that rapidly transforms both in the atmosphere and once inhaled. Because of this rapid transformation, limited information is available in terms of potential human exposures and adverse health effects. Young rats were exposed to whole diesel emissions (DE) adjusted to 300 µg/m3 of particulate matter (containing 3.5 ppm NO) or 0, 3, or 10 ppm NO as a positive control. Animals were also pre-injected (i.p.) with either saline or n-acetyl-cysteine (NAC), a precursor of glutathione. Predictably, pure NO exposures led to a concentration-dependent increase in plasma nitrates compared to controls, which lasted for roughly 4 hr post-exposure. Whole DE exposure for 1 hr also led to a doubling of plasma NOx. NAC injection increased the levels of plasma nitrates and nitrites (NOx) in the DE exposure group. Inhibition of NOS by L-NNA did not block the rise in plasma NOx, demonstrating that the increase was entirely due to exogenous sources. Both DE and pure NO exposures paradoxically led to elevated eNOS expression in aortic tissue. Furthermore, coronary arterioles from NO-exposed animals exhibited greater constriction to endothelin-1 compared to controls, consistent with a derangement of the NOS system. Thus, NO may be an important contributor to traffic-related cardiovascular morbidity although further research is necessary for proper hazard identification.

Knuckles, Travis L.; Buntz, Jennifer G.; Paffett, Michael; Channell, Meghan; Harmon, Molly; Cherng, Tom; Lucas, Selita N.; McDonald, Jacob D.; Kanagy, Nancy L.; Campen, Matthew J.

2011-01-01

235

Construction and characterization of nitrate and nitrite respiring Pseudomonas putida KT2440 strains for anoxic biotechnical applications.  

PubMed

Pseudomonas putida KT2440 is frequently used in biotechnical research and applications due to its metabolic versatility and organic solvent resistance. A major drawback for a broad application is the inability of the bacterium to survive and grow under anoxic conditions, which prohibits the production of oxygen-sensitive proteins and metabolites. To develop a P. putida strain, which is able to survive under anoxic conditions, the enzymatic systems of anaerobic nitrate and nitrite respiration were introduced into KT2440. For this purpose, two cosmids encoding all structural, maturation and regulatory genes for P. aeruginosa nitrate reductase (pNAR) and nitrite- and nitric oxide reductase (pNIR-NOR) were stably maintained in P. putida KT2440. Transcriptome analyses revealed expression of the encoded nar, nir and nor operons and accessory genes under anoxic conditions. The produced enzyme systems efficiently reduced nitrate or nitrite, respectively, sustaining anaerobic life of recombinant KT2440. Interestingly, anaerobic life of P. putida induced genes involved in arginine-fermentation and genes encoding a putative copper stress resistance operon. PMID:23036925

Steen, Annika; Utkür, F Özde; Borrero-de Acuña, José Manuel; Bunk, Boyke; Roselius, Louisa; Bühler, Bruno; Jahn, Dieter; Schobert, Max

2012-10-02

236

Hydroxy peroxy nitrites and nitrates from OH initiated reactions of isoprene.  

PubMed

The reaction of hydroxy peroxy radicals (RO(2)) with NO represents one of the most crucial tropospheric processes, leading to terrestrial ozone formation or NO(x)() removal and chain termination. We investigate the formation of hydroxy peroxy nitrites (ROONO) and nitrates (RONO(2)) from the OH-isoprene reactions using DFT and ab initio theories and variational RRKM/master equation (vRRKM/ME) formalism. The binding energies of ROONO from NO addition to RO(2) are determined to be in the range of 20-22 kcal mol(-)(1), and the bond dissociation energies of ROONO to form an alkoxy radical (RO) and NO(2) range from 6 to 9 kcal mol(-)(1). Isomerization of ROONO to RONO(2) is exothermic by 22-28 kcal mol(-)(1). The entrance and exit channels of the RO(2)-NO reaction are found to be barrierless, and the rate constants to form ROONO are calculated to be 3 x 10(-)(12) to 2 x 10(-)(11) cm(3) molecule(-)(1) s(-)(1) using the canonical variational transition state theory. The vRRKM/ME analysis reveals negligible stabilization of excited ROONO and provides an assessment of ROONO isomerization to RONO(2). PMID:12167055

Zhang, Dan; Zhang, Renyi; Park, Jiho; North, Simon W

2002-08-14

237

The nitrate to ammonia and ceramic (NAC) process -- a newly developed low-temperature technology  

SciTech Connect

Bench-top feasibility studies with Hanford single-shell tank (SST) simulants, using a new low-temperature (50-60C) process for converting nitrate to ammonia and ceramic (NAC), showed that between 90 and 99% of the nitrate at Hanford can be readily converted to ammonia. Aluminum powders or shot can be used to convert alkaline, nitrate-based supernate to ammonia and an alumina-silica-based ceramic solid. The process may utilize already contaminated aluminum scrap metal from various DOE sites to effect the conversion. The final nitrate-free ceramic product can be calcined, pressed, and sintered like any other ceramic. Based on starting volumes of 6.2 and 3.1 M sodium nitrate solution (probable supernate concentrations resulting from salt-cake/sludge removal from Hanford SSTs), volume reductions as high as 70% are currently obtained, compared with an expected 40 to 50% volume increase if the Hanford supernate were grouted. Engineering data indicate that the process will be very economical. Data were used to cost a batch facility with a production rate of 1200 kilograms of nitrate per hour for processing all the Hanford SST waste over 20 years. Process cost analysis indicates that between $2.01 and 2.66 will be required to convert each kilogram of nitrate. These costs are one-third to one-half of the processing costs for electrolytic and thermal processes. The ceramic waste form offers other cost savings associated with a smaller volume of waste as well as eliminates other process steps such as grouting. Silica added to the reactor, based upon the total sodium in the waste, permits us to actually bind the sodium in a nepheline phase of the final ceramic structure as well as bind most metals and nonmetals in the ceramic.

Mattus, A.J.; Lee, D.D.

1993-06-01

238

Effects of long-term fertilization of forest soils on potential nitrification and on the abundance and community structure of ammonia oxidizers and nitrite oxidizers.  

PubMed

Forest fertilization in British Columbia is increasing, to alleviate timber shortfalls resulting from the mountain pine beetle epidemic. However, fertilization effects on soil microbial communities, and consequently ecosystem processes, are poorly understood. Fertilization has contrasting effects on ammonia-oxidizing bacteria and archaea (AOB and AOA) in grassland and agricultural ecosystems, but there are no studies on AOB and AOA in forests. We assessed the effect of periodic (6-yearly application 200 kg N ha?¹) and annual (c. 75 kg N ha?¹) fertilization of lodgepole pine and spruce stands at five long-term maximum productivity sites on potential nitrification (PN), and the abundance and diversity of AOB, AOA and Nitrobacter and Nitrospira-like nitrite-oxidizing bacteria (NOB). Fertilization increased AOB and Nitrobacter-like NOB abundances at some sites, but did not influence AOA and Nitrospira-like NOB abundances. AOB and Nitrobacter-like NOB abundances were correlated with PN and soil nitrate concentration; no such correlations were observed for AOA and Nitrospira-like NOB. Autotrophic nitrification dominated (55–97%) in these forests and PN rates were enhanced for up to 2 years following periodic fertilization. More changes in community composition between control and fertilized plots were observed for AOB and Nitrobacter-like NOB than AOA. We conclude that fertilization causes rapid shifts in the structure of AOB and Nitrobacter-like NOB communities that dominate nitrification in these forests. PMID:22066501

Wertz, Sophie; Leigh, Adam K K; Grayston, Sue J

2012-01-01

239

A heme-C-containing enzyme complex that exhibits nitrate and nitrite reductase activity from the dissimilatory iron-reducing bacterium Geobacter metallireducens.  

PubMed

Nitrate reduction in the dissimilatory iron-reducing bacterium Geobacter metallireducens was investigated. Nitrate reductase and nitrite reductase activities in nitrate-grown cells were detected only in the membrane fraction. The apparent K(m )values for nitrate and nitrite were determined to be 32 and 10 microM, respectively. Growth on nitrate was not inhibited by either tungstate or molybdate at concentrations of 1 mM or less, but was inhibited by both at 10 and 20 mM. Nitrate and nitrite reductase activity in the membrane fraction was not, however, affected by dialysis with 20 mM tungstate. An enzyme complex that exhibited both nitrate and nitrite reductase activity was solubilized from membrane fractions with CHAPS and was partially purified by preparative gel electrophoresis. It was found to be composed of four different polypeptides with molecular masses of 62, 52, 36, and 16 kDa. The 62-kDa polypeptide [a low-midpoint potential (-207 mV), multiheme cytochrome c] exhibited nitrite reductase activity under denaturing conditions. No molybdenum was detected in the complex by plasma-emission mass spectrometry. PMID:10550473

Martínez Murillo, F; Gugliuzza, T; Senko, J; Basu, P; Stolz, J F

1999-11-01

240

Changes in Benthic Denitrification, Nitrate Ammonification, and Anammox Process Rates and Nitrate and Nitrite Reductase Gene Abundances along an Estuarine Nutrient Gradient (the Colne Estuary, United Kingdom)? †  

PubMed Central

Estuarine sediments are the location for significant bacterial removal of anthropogenically derived inorganic nitrogen, in particular nitrate, from the aquatic environment. In this study, rates of benthic denitrification (DN), dissimilatory nitrate reduction to ammonium (DNRA), and anammox (AN) at three sites along a nitrate concentration gradient in the Colne estuary, United Kingdom, were determined, and the numbers of functional genes (narG, napA, nirS, and nrfA) and corresponding transcripts encoding enzymes mediating nitrate reduction were determined by reverse transcription-quantitative PCR. In situ rates of DN and DNRA decreased toward the estuary mouth, with the findings from slurry experiments suggesting that the potential for DNRA increased while the DN potential decreased as nitrate concentrations declined. AN was detected only at the estuary head, accounting for ?30% of N2 formation, with 16S rRNA genes from anammox-related bacteria also detected only at this site. Numbers of narG genes declined along the estuary, while napA gene numbers were stable, suggesting that NAP-mediated nitrate reduction remained important at low nitrate concentrations. nirS gene numbers (as indicators of DN) also decreased along the estuary, whereas nrfA (an indicator for DNRA) was detected only at the two uppermost sites. Similarly, nitrate and nitrite reductase gene transcripts were detected only at the top two sites. A regression analysis of log(n + 1) process rate data and log(n + 1) mean gene abundances showed significant relationships between DN and nirS and between DNRA and nrfA. Although these log-log relationships indicate an underlying relationship between the genetic potential for nitrate reduction and the corresponding process activity, fine-scale environmentally induced changes in rates of nitrate reduction are likely to be controlled at cellular and protein levels.

Dong, Liang F.; Smith, Cindy J.; Papaspyrou, Sokratis; Stott, Andrew; Osborn, A. Mark; Nedwell, David B.

2009-01-01

241

NITRATE CONTAMINATION OF GROUND WATER (GW-761)  

EPA Science Inventory

The occurrence of nitrate and related compounds in ground water is discussed from the perspectives of its natural as well as anthropogenic origins. A brief explanation of the nitrogen cycle touches on the production as well as utilization of ammonia, nitrite, nitrate, and nitrog...

242

Sensitivity of modelled sulphate and nitrate aerosol to cloud, pH and ammonia emissions  

NASA Astrophysics Data System (ADS)

A Lagrangian dispersion model has been used to predict daily sulphate aerosol in 2006 at five UK rural measurement sites and hourly nitrate aerosol in April 2003 at Harwell (UK). The sensitivity of aqueous phase sulphate production to the meteorological input has been investigated. Large differences were found between cloud fraction and cloud liquid water output from the regional and mesoscale Met Office Unified Model. The impact on the sulphate aerosol was relatively small, with the mesoscale meteorology giving better results. Sulphate aerosol production in the aqueous phase was found to be very sensitive to modelled cloud pH. As the cloud becomes acidic sulphate production is greatly limited, conversely if the cloud is basic large amounts of sulphate aerosol are produced. A fixed model pH of 5.8 was found to produce better results than allowing the model to calculate pH which resulted in large over-predictions of measured sulphate aerosol in some episodes. Nitrate aerosol was not sensitive to cloud variables or pH, but showed a slight increase with 30% more ammonia emissions, and a slight decrease with 30% less ammonia. Sulphate production in model runs with fixed pH was not sensitive to changing ammonia emissions, however the sulphate production with modelled pH was very sensitive to plus or minus 30% ammonia. This work suggests that good modelling of ammonia is essential to correct estimation of aqueous phase sulphate aerosol if cloud pH is modelled. It is concluded that modelling to estimate the effect of reduced ammonia emission scenarios on future ambient aerosol levels should also take into account the neutralising effect of ammonia in cloud and hence the effect on aqueous phase production of sulphate.

Redington, A. L.; Derwent, R. G.; Witham, C. S.; Manning, A. J.

243

Detection ofBacterial Nitrite Production fromNitrate bya Nitrate-Starch-I odide AgarMedium  

Microsoft Academic Search

A mediumconsisting ofnitrate agar (Difco), modified bytheaddition of1% starch and1%KI,was usedtodetect theproduction ofnitrite bya numberof different bacterial species. Thecommonly usednitrite detection method isaGriess reaction (3). Thisprocedure involves theuseofa-naphthylamine, acompound which hasbeenclassified bytheOccupational Safety andHealth Administration oftheU.S.Depart- mentofLabor(1)asahumanbladder carcino- gen.A less hazardous methodofdetermining nitrite production bymicroorganisms hasbeen devised based onthereaction between acidified nitrite andiodide ions andtheconcomitant pro- duction offree iodine (2).

GERALD S. REISNER

1978-01-01

244

Free nitrous acid selectively inhibits and eliminates nitrite oxidizers from nitrifying sequencing batch reactor.  

PubMed

In a complete nitrification sequencing batch reactor (CNSBR), where ammonium containing wastewater (200-1,000 mg N/L) is completely oxidized to nitrate up to 2.4 kg NH(4) (+)-N/m(3) d, both ammonia oxidizers and nitrite oxidizers were enriched in the sludge granules. Quantitative fluorescence in situ hybridization analyses of the sludge granules of the CNSBR showed that ammonia oxidizers and nitrite oxidizers occupied 31 and 4.2% of total bacteria, respectively. Most of the nitrite oxidizers were Nitrobacter species (95% of the nitrite oxidizers) and the remainder was Nitrospira species. The population of nitrite oxidizers was significantly higher than that of partial nitrification SBR (PNSBR) where most of the ammonium was oxidized to nitrite. The PNSBR had 37% (ammonia oxidizers) and 0.4% (nitrite oxidizers) of total bacteria. Comparative study with CNSBR and PNSBR revealed that free nitrous acid, rather than free ammonia, played a critical inhibition role to wash out nitrite oxidizers from the reactor. The concentrations of free ammonia and nitrite as well as free nitrous acid in the CNSBR selected Nitrobacter as the dominant nitrite oxidizers rather than Nitrospira. PMID:21874514

Kim, Dong-Jin; Seo, Doug-Won; Lee, Seung-Hwan; Shipin, Oleg

2011-08-28

245

Kinetics of nirS Expression (Cytochrome cd 1 Nitrite Reductase) in Pseudomonas stutzeri during the Transition from Aerobic Respiration to Denitrification: Evidence for a Denitrification Specific Nitrate and Nitrite-Responsive Regulatory System  

Microsoft Academic Search

After shifting an oxygen-respiring culture of Pseudomonas stutzeri to nitrate or nitrite respiration, we directly monitored the expression of the nirS gene by mRNA analysis. nirS encodes the 62-kDa subunit of the homodimeric cytochrome cd1 nitrite reductase involved in denitrification. Information was sought about the requirements for gene activation, potential regulators of such activation, and signal transduction pathways triggered by

ELISABETH HARTIG; WALTER G. ZUMFT

1999-01-01

246

Intracellular Conversion of Environmental Nitrate and Nitrite to Nitric Oxide with Resulting Developmental Toxicity to the Crustacean Daphnia magna  

PubMed Central

Background Nitrate and nitrite (jointly referred to herein as NOx) are ubiquitous environmental contaminants to which aquatic organisms are at particularly high risk of exposure. We tested the hypothesis that NOx undergo intracellular conversion to the potent signaling molecule nitric oxide resulting in the disruption of endocrine-regulated processes. Methodology/Principal Findings These experiments were performed with insect cells (Drosophila S2) and whole organisms Daphnia magna. We first evaluated the ability of cells to convert nitrate (NO3?) and nitrite (NO2?) to nitric oxide using amperometric real-time nitric oxide detection. Both NO3? and NO2? were converted to nitric oxide in a substrate concentration-dependent manner. Further, nitric oxide trapping and fluorescent visualization studies revealed that perinatal daphnids readily convert NO2? to nitric oxide. Next, daphnids were continuously exposed to concentrations of the nitric oxide-donor sodium nitroprusside (positive control) and to concentrations of NO3? and NO2?. All three compounds interfered with normal embryo development and reduced daphnid fecundity. Developmental abnormalities were characteristic of those elicited by compounds that interfere with ecdysteroid signaling. However, no compelling evidence was generated to indicate that nitric oxide reduced ecdysteroid titers. Conclusions/Significance Results demonstrate that nitrite elicits developmental and reproductive toxicity at environmentally relevant concentrations due likely to its intracellular conversion to nitric oxide.

Hannas, Bethany R.; Das, Parikshit C.; Li, Hong; LeBlanc, Gerald A.

2010-01-01

247

Precursor/product studies of macrophage synthesis of nitrite, nitrate and N-nitrosamines  

SciTech Connect

Previous experiments showed that nitrite, nitrate and N-nitrosamine synthesis was carried out by both stimulated macrophages (M phi) and a number of M phi cell lines. Here the authors report the precursor to NO/sub 2//sup -/, NO/sub 3//sup -/, and the source of the nitrosating agent. Previous kinetic studies established a time lag for NO/sub 2//sup -//NO/sub 3//sup -/ synthesis during which protein synthesis required for product formation occurred. Medium change after the protein synthesis phase showed that L-arginine was the only amino acid essential for the synthesis. Other precursors were homoarginine, arginine methyl ester, arginine infinity-hydroxamate, argininamide and the peptide arginine-aspartate. Glutamine, citrulline, ornithine, hydroxylamine and D-arginine were among some of the non-precursors. Canavanine though not a precursor inhibited arginine-derived NO/sub 2/-/NO/sub 3//sup -/ synthesis while D-arginine had no effect. When /sup 15/N-arginine (guanido-/sup 15/N/sub 2/, 95%) was used, GC/MS results showed that all the NO/sub 2//sup -//NO/sub 3//sup -/ synthesized was derived exclusively from these two guanido nitrogens. Similar labeling experiments carried out in the presence of morpholine showed that the isotopic enrichment of N-nitrosomorpholine was the same as that of NO/sub 2//sup -//NO/sub 3//sup -/ synthesized, suggesting that the nitrosating agent is a common intermediate. In conclusion, NO/sub 2//sup -//NO/sub 3//sup -/ and N-nitrosomorpholine synthesis by stimulated macrophages is derived specifically from the two guanido nitrogens of arginine.

Iyengar, R.; Marletta, M.A.

1987-05-01

248

Self?purification of small freshwater streams: Phosphate, Nitrate, and Ammonia removal  

Microsoft Academic Search

Uptake of stream nutrients by organisms or sediments of the stream bed is affected by the nutrient loading to which the stream is accustomed. In a stream with nutrient?poor waters, added phosphate and ammonia were removed rapidly and efficiently at water temperatures within the range 4.5–15.0°c on passing over a mat of filamentous algae and trapped sediment. Nitrate was removed

R. H. S. McColl

1974-01-01

249

Molecular and catalytic properties of a novel cytochrome c nitrite reductase from nitrate-reducing haloalkaliphilic sulfur-oxidizing bacterium Thioalkalivibrio nitratireducens  

Microsoft Academic Search

A highly active cytochrome c nitrite reductase from the haloalkaliphilic sulfur-oxidizing non-ammonifying bacterium Tv. nitratireducens strain ALEN 2 (TvNiR) was isolated and purified to apparent electrophoretic homogeneity. The enzyme catalyzes reductive conversion of nitrite and hydroxylamine to ammonia without release of any intermediates, as well as reduction of sulfite to sulfide. TvNiR also possesses peroxidase activity. In solution TvNiR exists

Tamara V. Tikhonova; Alvira Slutsky; Alexey N. Antipov; Konstantin M. Boyko; Konstantin M. Polyakov; Dimitry Y. Sorokin; Renata A. Zvyagilskaya; Vladimir O. Popov

2006-01-01

250

Reversible intercalation of ammonia molecules into a layered double hydroxide structure without exchanging nitrate counter-ions  

SciTech Connect

A zinc/aluminum LDH was precipitated with recycled ammonia from a chemical vapor deposition reaction. The LDH presented a crystalline phase with basal distance of 8.9 A, typical for nitrate-containing LDHs, and another phase with a basal distance of 13.9 A. Thermal treatment at 150 {sup o}C eliminated the phase with the bigger basal distance leaving only the anhydrous nitrate-intercalated LDH structure with 8.9 A. Intense N-H stretching modes in the FTIR spectra suggested that the expansion was due to intercalation of ammonia in the form of [NH{sub 4}(NH{sub 3}){sub n}]{sup +} species. When additional samples were precipitated with pure ammonia, the conventional LDH nitrate structure was obtained (8.9 A basal distance) at pH=7, as well as a pure crystalline phase with 13.9 A basal distance at pH=10 due to ammonia intercalation that can be removed by heating at 150 {sup o}C or by stirring in acetone, confirming a unusual sensu stricto intercalation process into a LDH without exchanging nitrate ions. - Graphical abstract: LDH-nitrate precipitated with ammonia expands the interlayer space if ammonia is bubbled up to pH 10. The basal distance decreased when the compound was heated at 150 {sup o}C or stirred in acetone. Nitrate ions are not exchanged.

Carbajal Arizaga, Gregorio Guadalupe, E-mail: gregoriocarbajal@yahoo.com.m [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia, Km. 107 Carretera Tijuana-Ensenada, Apdo. Postal 14, C.P. 22800. Ensenada, Baja California (Mexico); Wypych, Fernando [CEPESQ-Research Centre of Applied Chemistry, Department of Chemistry, Federal University of Parana, P.O. Box 19081, 81531-980 Curitiba, PR (Brazil); Castillon Barraza, Felipe; Contreras Lopez, Oscar Edel [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia, Km. 107 Carretera Tijuana-Ensenada, Apdo. Postal 14, C.P. 22800. Ensenada, Baja California (Mexico)

2010-10-15

251

Nitrosamine, nitrate and nitrite in relation to gastric cancer: a case-control study in Marseille, France.  

PubMed

A case-control study on gastric cancer and diet was conducted in Marseille (France). Ninety-two patients with histologically confirmed adenocarcinoma and 128 controls undergoing functional reeducation for injuries or trauma were interviewed by a trained dietician using a dietary history questionnaire on their usual diet during the year preceding the first symptoms for cases, or preceding interview for controls. Intake of nitrite, nitrate and pre-formed N-nitrosodimethylamine (NDMA) from food was estimated using a food composition table compiled ad hoc. Odds ratios (ORs) were calculated after adjustment for age, sex, occupation and calorie intake. The results indicated that high intake of NDMA was associated with increased risk for gastric cancer. The ORs for the second and third tertile of NDMA intake were: OR2 = 4.13 (95% CI = 0.93 18.27) and OR3 = 7.00 (95% CI = 1.85 to 26.46). Intake of nitrate and nitrite was not associated with increased risk of stomach cancer. Consumption of vegetables was protective in general and independent of their estimated nitrate content. PMID:7489775

Pobel, D; Riboli, E; Cornée, J; Hémon, B; Guyader, M

1995-02-01

252

Reduction of nitrate and nitrite in vegetable juices prior to lactic acid fermentation  

Microsoft Academic Search

The reduction of the nitrate content in vegetable juices has an important effect on the total intake of nitrate by humans. Carrot puree containing 500 mg\\/1 nitrate was treated with immobilized cells of Halomonas spec, at 6°C. The nitrate was reduced within five hours quantitatively to nitrous oxide.Lactic acid fermentation by Leuconostoc mesenteroides performed after completion of the denitrification process

J. Emig; C. Meisel; G. Wolf; K. Gierschner; W. P. Hammes

1990-01-01

253

Close genetic relationship between Nitrobacter hamburgensis nitrite oxidoreductase and Escherichia coli nitrate reductases  

Microsoft Academic Search

The nitrite oxidoreductase (NOR) from the facultative nitrite-oxidizing bacterium Nitrobacter hamburgensis X14 was investigated genetically. In order to develop a probe for the gene norB, the N-terminal amino acid sequence of the NOR ß-subunit (NorB) was determined. Based on that amino acid sequence, an oligo-nucleotide was derived that was used for the identification and cloning of gene norB. Sequence analysis

Karin Kirstein; Eberhard Bock

1993-01-01

254

The effect of acute poisoning with potassium nitrate and sodium nitrite on the processes of intestinal absorption of D-xylose in rats  

Microsoft Academic Search

The intestinal transport of D-xylose was studied during the acute poisoning of male Wistar rats with orally administered potassium nitrate and sodium nitrite. At the peak of xylose absorption, the metabolic parameters of Na+\\/K+-ATPase, alkaline phosphatase, oxygen uptake, and lactic acid level were determined in the small intestine mucosa. Nitrite in a dose of 80 mg NaNO2\\/kg b.w. increased the

Ireneusz Grudzifiski; Antoni Szyma?ski

1991-01-01

255

A mixture of nitrite-oxidizing and denitrifying microorganisms affects the ?18O of dissolved nitrate during anaerobic microbial denitrification depending on the ?18O of ambient water  

NASA Astrophysics Data System (ADS)

The stable isotopes 15N/14N and 18O/16O of nitrate are frequently used to determine sources of nitrate and to assess denitrification processes in the environment. Nitrate isotope ratios are thought to be conservative unless involved in (bio-) chemical conversion processes. Thus, stable isotopes are considered to be a reliable tool to determine sources of nitrate in aquatic habitats even after transport and dilution has occurred. Denitrification is known to shift both isotope ratios towards higher ?-values. A fixed ratio of 0.5 for ??18O/??15N has been proposed and has been widely used to detect denitrification in terrestrial environments, predominantly in aquifers. However, it is observed in environmental and laboratory studies that this ratio actually varies between less than 0.5 and 1 for uncertain reasons with laboratory studies usually describing a ratio close to 1. Here we report results of anoxic incubation experiments with natural populations of nitrate-reducing microorganisms using sediments from three different environments. In our experiments we used water with a ?18O in excess of 500‰ and found a microbially mediated influence of the oxygen isotopic composition of ambient water on the isotopic composition of the residual dissolved nitrate. We found up to 5.7 ± 2.3% of the oxygen-atoms in the residual dissolved nitrate was exchanged by oxygen-atoms from ambient water within the limited timeframe of the experiments. The fastest incorporation of oxygen-atoms from water into dissolved nitrate correlated with the highest intermittent nitrite concentrations observed in our experiments. In a second series of batch experiments we also found that pure cultures of the nitrite-oxidizing bacterium Nitrobacter vulgaris promoted the incorporation of oxygen atoms from ambient water into dissolved nitrate under anoxic conditions. Presumably this happens via a reoxidation of intermediary formed nitrite by the enzyme "nitrite oxidoreductase" (NXR) in concurrence with respiratory nitrate reduction. In this context, our hypothesis is a reversibility of the reactions at the NXR enzyme even in the absence of external electron acceptors for nitrite oxidation. We suggest that the presence of nitrite-oxidizing microorganisms in aquatic environments may catalyse such an incorporation of oxygen-atoms stemming from ambient water into nitrate. This process may thus mask the original ?18O value of nitrate sources during denitrification and also distort the observed enrichment of 18O that is ascribed to denitrification. Our results are highly likely an explanation of the deviation of the described variable ??18O/??15N ratios for denitrification in terrestrial field studies from the values observed in the laboratory on pure cultures.

Wunderlich, Anja; Meckenstock, Rainer U.; Einsiedl, Florian

2013-10-01

256

Maternal characteristics associated with the dietary intake of nitrates, nitrites, and nitrosamines in women of child-bearing age: a cross-sectional study  

PubMed Central

Background Multiple N-nitroso compounds have been observed in animal studies to be both mutagenic and teratogenic. Human exposure to N-nitroso compounds and their precursors, nitrates and nitrites, can occur through exogenous sources, such as diet, drinking water, occupation, or environmental exposures, and through endogenous exposures resulting from the formation of N-nitroso compounds in the body. Very little information is available on intake of nitrates, nitrites, and nitrosamines and factors related to increased consumption of these compounds. Methods Using survey and dietary intake information from control women (with deliveries of live births without major congenital malformations during 1997-2004) who participated in the National Birth Defects Prevention Study (NBDPS), we examined the relation between various maternal characteristics and intake of nitrates, nitrites, and nitrosamines from dietary sources. Estimated intake of these compounds was obtained from the Willet Food Frequency Questionnaire as adapted for the NBDPS. Multinomial logistic regression models were used to estimate odds ratios and 95% confidence intervals for the consumption of these compounds by self-reported race/ethnicity and other maternal characteristics. Results Median intake per day for nitrates, nitrites, total nitrites (nitrites + 5% nitrates), and nitrosamines was estimated at 40.48 mg, 1.53 mg, 3.69 mg, and 0.472 ?g respectively. With the lowest quartile of intake as the referent category and controlling for daily caloric intake, factors predicting intake of these compounds included maternal race/ethnicity, education, body mass index, household income, area of residence, folate intake, and percent of daily calories from dietary fat. Non-Hispanic White participants were less likely to consume nitrates, nitrites, and total nitrites per day, but more likely to consume dietary nitrosamines than other participants that participated in the NBDPS. Primary food sources of these compounds also varied by maternal race/ethnicity. Conclusions Results of this study indicate that intake of nitrates, nitrites, and nitrosamines vary considerably by race/ethnicity, education, body mass index, and other characteristics. Further research is needed regarding how consumption of foods high in nitrosamines and N-nitroso precursors might relate to risk of adverse pregnancy outcomes and chronic diseases.

2010-01-01

257

Study on the oxyhemocyanin, deoxyhemocyanin, oxygen affinity and acid-base balance of Marsupenaeus japonicus following exposure to combined elevated nitrite and nitrate.  

PubMed

Marsupenaeus japonicus (11.47+/-0.71 g) exposed individually to six different nitrite and nitrate regimes [(0.002 (control), 0.359 and 1.456 mM nitrite combined with 0.005 (control) and 7.458 mM nitrate)] in salinity of 30 ppt (parts per thousand) were examined for hemocyanin oxygen affinity, the fractionation of oxyhemocyanin and deoxyhemocyanin, and the acid-base balance after 24 h. Ambient nitrite at concentration of 0.359 mM caused reduction of oxyhemocyanin and protein by 27 and 11%, respectively, whereas ambient nitrate as high as 7.458 mM caused reduction of oxyhemocyanin and protein by 10 and 7%. Ambient nitrite at concentration of 1.456 mM caused increases of P(50) (indicating reduced oxygen affinity) and pO(2), but caused reduction in hemolymph pCO(2), pH, HCO(3)(-) and TCO(2). Following exposure to combined solutions of 1.456 mM nitrite and 7.458 mM nitrate there were no further changes in oxyhemocyanin, protein, hemolymph P(50), pO(2), pCO(2), HCO(3)(-) and TCO(2), but there was a significant reduction of pH. PMID:12359389

Cheng, Sha-Yen; Chen, Jiann-Chu

2002-12-01

258

Preliminary safe-handling experiments on a mixture of cesium nickel ferrocyanide and equimolar sodium nitrate/nitrite  

SciTech Connect

As part of the Hanford Site's evaluation of the potential hazards associated with the storage of ferrocyanide wastes generated when ferrocyanide was used to scavenge radiocesium from waste supernates in the 1950s, the Pacific Northwest Laboratory (PNL) subcontracted with Los Alamos National Laboratory (LANL) to perform a series of sensitivity tests. These test supplement PNL's thermal sensitivity testing results on the reactivity of cesium nickel ferrocyanide (Cs{sub 2}NiFe(CN){sub 6}) and nitrates and nitrites (Burger and Schelle 1991). LANL used a selected set of their standard tests to determine the sensitivity of a mixture of Cs{sub 2}NiFe(CN){sub 6} (FECN-1) and equimolar sodium nitrate and nitrite oxidant to nonthermal and thermal stimuli. The stoichiometric ratio of oxidant to Cs{sub 2}NiFe(CN){sub 6} in the tested mixture FECN-1 was 1.1:1. The appendix presents the results of the LANL testing of the sensitivity of FECN-1 to initiation by mechanical impact, spark, friction, and various thermal conditions. In addition to the sensitivity testing, LANL used an Accelerating Rate Calorimeter (ARC) to estimate the behavior of large batches of the mixture.

Scheele, R.D. (Pacific Northwest Lab., Richland, WA (United States)); Cady, H.H. (Los Alamos National Lab., NM (United States))

1992-01-01

259

Preliminary safe-handling experiments on a mixture of cesium nickel ferrocyanide and equimolar sodium nitrate/nitrite  

SciTech Connect

As part of the Hanford Site`s evaluation of the potential hazards associated with the storage of ferrocyanide wastes generated when ferrocyanide was used to scavenge radiocesium from waste supernates in the 1950s, the Pacific Northwest Laboratory (PNL) subcontracted with Los Alamos National Laboratory (LANL) to perform a series of sensitivity tests. These test supplement PNL`s thermal sensitivity testing results on the reactivity of cesium nickel ferrocyanide (Cs{sub 2}NiFe(CN){sub 6}) and nitrates and nitrites (Burger and Schelle 1991). LANL used a selected set of their standard tests to determine the sensitivity of a mixture of Cs{sub 2}NiFe(CN){sub 6} (FECN-1) and equimolar sodium nitrate and nitrite oxidant to nonthermal and thermal stimuli. The stoichiometric ratio of oxidant to Cs{sub 2}NiFe(CN){sub 6} in the tested mixture FECN-1 was 1.1:1. The appendix presents the results of the LANL testing of the sensitivity of FECN-1 to initiation by mechanical impact, spark, friction, and various thermal conditions. In addition to the sensitivity testing, LANL used an Accelerating Rate Calorimeter (ARC) to estimate the behavior of large batches of the mixture.

Scheele, R.D. [Pacific Northwest Lab., Richland, WA (United States); Cady, H.H. [Los Alamos National Lab., NM (United States)

1992-01-01

260

Nicotinamide Adenine Dinucleotide Phosphate Phosphatase Facilitates Dark Reduction of Nitrate: Regulation by Nitrate and Ammonia  

Microsoft Academic Search

Leaves of 15 - 30-d-old plants of sunflower and jute were harvested at 10.00 or 23.00 (local time) and measured immediately,\\u000a or those harvested at 10.00 were incubated for one hour in sunlight either in water or 5 mM methionine sulfoximine (MSX) solution\\u000a and then for three hours in dark either in water or 15 mM KNO3 solution. Nitrate feeding

D. Pattanayak; S. R. Chatterjee

1998-01-01

261

Endogenous superoxide production and the nitrite/nitrate ratio control the concentration of bioavailable free nitric oxide in leaves.  

PubMed

We have quantitatively measured nitric oxide production in the leaves of Arabidopsis thaliana and Vicia faba by adapting ferrous dithiocarbamate spin tapping methods previously used in animal systems. Hydrophobic diethyldithiocarbamate complexes were used to measure NO interacting with membranes, and hydrophilic N-methyl-d-glucamine dithiocarbamate was used to measure NO released into the external solution. Both complexes were able to trap levels of NO, readily detectable by EPR spectroscopy. Basal rates of NO production (in the order of 1 nmol g(-) (1) h(-1)) agreed with previous studies. However, use of methodologies that corrected for the removal of free NO by endogenously produced superoxide resulted in a significant increase in trapped NO (up to 18 nmol g(-) (1) h(-1)). Basal NO production in leaves is therefore much higher than previously thought, but this is masked by significant superoxide production. The effects of nitrite (increased rate) and nitrate (decreased rate) are consistent with a role for nitrate reductase as the source of this basal NO production. However, rates under physiologically achievable nitrite concentrations never approach that reported following pathogen induction of plant nitric-oxide synthase. In Hibiscus rosa sinensis, the addition of exogenous nitrite generated sufficient NO such that EPR could be used to detect its production using endogenous spin traps (forming paramagnetic dinitrosyl iron complexes). Indeed the levels of this nitrosylated iron pool are sufficiently high that they may represent a method of maintaining bioavailable iron levels under conditions of iron starvation, thus explaining the previously observed role of NO in preventing chlorosis under these conditions. PMID:15056652

Vanin, Anatoly F; Svistunenko, Dimitri A; Mikoyan, Vasak D; Serezhenkov, Vladimir A; Fryer, Michael J; Baker, Neil R; Cooper, Chris E

2004-03-31

262

Nitrite-oxidizing bacteria guild ecologyassociated with nitri¢cation failure in a continuous-£ow reactor  

Microsoft Academic Search

Nitrification is an important process for nitrogen removal in many wastewater treatment plants, which requires the mutualistic oxidation of ammonia to nitrate by ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). However, this process can be quite unpredictable because both guilds are conditionally sensitive to small changes in operating conditions. Here, dynamics are examined within the NOB guild in two parallel

Charles W. Knapp; David W. Graham

263

Measurement of Nitrite and Nitrate in Biological Fluids by Gas Chromatography–Mass Spectrometry and by the Griess Assay: Problems with the Griess Assay—Solutions by Gas Chromatography–Mass Spectrometry  

Microsoft Academic Search

Assay methods based on the Griess reaction are frequently used to measure nitrite and nitrate in urine, plasma, and other biological fluids. With minor exceptions, careful attention has not been paid in extending the Griess assay from aqueous solutions to biological fluids. In the present study, parallel measurements of nitrite and nitrate were performed in urine, plasma, and aqueous solutions

Dimitrios Tsikas; Frank-Mathias Gutzki; Stefan Rossa; Heinke Bauer; Christine Neumann; Katja Dockendorff; Jörg Sandmann; Jürgen C. Frölich

1997-01-01

264

Influence of Nitrate and Nitrite on Thyroid Hormone Responsive and Stress-Associated Gene Expression in Cultured Rana catesbeiana Tadpole Tail Fin Tissue  

PubMed Central

Nitrate and nitrite are common aqueous pollutants that are known to disrupt the thyroid axis. In amphibians, thyroid hormone (TH)-dependent metamorphosis is affected, although whether the effect is acceleration or deceleration of this developmental process varies from study to study. One mechanism of action of these nitrogenous compounds is through alteration of TH synthesis. However, direct target tissue effects on TH signaling are hypothesized. The present study uses the recently developed cultured tail fin biopsy (C-fin) assay to study possible direct tissue effects of nitrate and nitrite. Tail biopsies obtained from premetamorphic Rana catesbeiana tadpoles were exposed to 5 and 50?mg/L nitrate (NO3–N) and 0.5 and 5?mg/L nitrite (NO2–N) in the absence and presence of 10?nM T3. Thyroid hormone receptor ? (TR?) and Rana larval keratin type I (RLKI), both of which are TH-responsive gene transcripts, were measured using quantitative real time polymerase chain reaction. To assess cellular stress which could affect TH signaling and metamorphosis, heat shock protein 30, and catalase (CAT) transcript levels were also measured. We found that nitrate and nitrite did not significantly change the level of any of the four transcripts tested. However, nitrate exposure significantly increased the heteroscedasticity in response of TR? and RLKI transcripts to T3. Alteration in population variation in such a way could contribute to the previously observed alterations of metamorphosis in frog tadpoles, but may not represent a major mechanism of action.

Hinther, Ashley; Edwards, Thea M.; Guillette, Louis J.; Helbing, Caren C.

2012-01-01

265

Rheological properties of the product slurry of the Nitrate to Ammonia and Ceramic (NAC) process  

SciTech Connect

The Nitrate to Ammonia and Ceramic (NAC) process is an innovative technology for immobilizing the liquid from Low Level radioactive Waste (LLW). An experimental study was conducted to measure the rheological properties of the pipe flow of the NAC product slurry. Test results indicate that the NAC product slurry has a profound rheological behavior. At low solids concentration, the slurry exhibits a typical dilatant fluid (or shear thinning)fluid. The transition from dilatant fluid to pseudo-plastic fluid will occur at between 25% to 30% solids concentration in temperature ranges of 50--80{degree}C. Correlation equations are developed based on the test data.

Muguercia, I.; Yang, G.; Ebadian, M.A. [Florida International Univ., Miami, FL (United States). Dept. of Mechanical Engineering; Lee, D.D.; Mattus, A.J.; Hunt, R.D. [Oak Ridge National Lab., TN (United States)

1995-03-01

266

Identification of wheat ( Triticum aestivum L.) chromosomes with genes controlling the level of nitrate reductase, nitrite reductase, and acid proteinase using the Chinese Spring-Hope substitution lines  

Microsoft Academic Search

The levels of nitrate reductase, nitrite reductase, and acid proteinase were compared in the primary leaves of 8-day-old wheat seedlings of Chinese Spring, Hope, and the 21 disomic substitution lines of Hope in Chinese Spring. Two chromosomes, 7B and 7D, were considered to contain genes controlling the level of nitrate reductase. Substitution of Hope chromosome 7B caused a highly significant

J. H. Sherrard; D. L. Green; L. B. Swinden; M. J. Dalling

1976-01-01

267

Determination, by Flow-Injection Analysis, of Fluoride, Chloride, Phosphate, Ammonia, Nitrite, and Nitrate.  

National Technical Information Service (NTIS)

Recent World-wide efforts in environmental control have created an increasing demand for the efficient and sensitive determination of elements in waters such as rain, municipal supplies, rivers and effluents. The methods should reduce the time needed for ...

E. A. Jones

1985-01-01

268

Annual Dissolved Nitrite Plus Nitrate and Total Phosphorous Loads for the Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia River Basins, 1968-2004.  

National Technical Information Service (NTIS)

Annual stream-water loads were calculated near the outlet of four of the larger river basins (Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia) in the United States for dissolved nitrite plus nitrate (NO2 + NO3) and total phosphorus using ...

B. T. Aulenbach

2006-01-01

269

Characterization and reduction of interferences in flow-injection analysis for the in situ determination of nitrate and nitrite in sea water  

Microsoft Academic Search

The aim of this work is to improve the precision and the sensitivity of nitrite and nitrate determination by flow-injection analysis (FIA) for an in situ utilization. Two kinds of signal treatment are proposed in order to eliminate the refractive index provoked by the heterogeneous flow in FIA and the errors induced by temperature, salinity and pressure variations. The concentration

Anne Daniel; Dominique Birot; Michel Lehaitre; Jacques Poncin

1995-01-01

270

Copper status of mice fed hydrogenated vegetable oil, cocoa butter, fresh and cured pork from high and low nitrate\\/nitrite containing diets  

Microsoft Academic Search

The objectives of this study were to determine the effects of hydrogenated vegetable oil, cocoa butter, fresh and cured pork from high (spinach = 0.2%) and low (spinach = 0.02%) nitrate\\/nitrite containing diets on copper status of mice. The dietary treatments had no significant effects on urinary and fecal copper excretions and whole blood and liver copper contents of mice.

Soon-Jae Joo; Constance Kies; Marilynn Schnepf

1995-01-01

271

Systemic plasma levels of nitrite/nitrate (NOx) reflect brachial flow-mediated dilation responses in young men and women.  

PubMed

1. The aim of the present study was to determine the relationship between plasma levels of nitrite/nitrite (NO(x)) and brachial flow-mediated dilation (FMD) in healthy young men and women. 2. Brachial artery FMD was assessed non-invasively using high-resolution ultrasound in 36 young men and women (21 +/- 3 years; 18 men and 18 women). Blood samples for NO(x) assays were collected from an indwelling venous catheter in the forearm following an overnight fast and a 36 h low-nitrate diet. 3. Plasma levels of NO(x) were related to peak brachial FMD% (r = 0.53; P = 0.001). The relationship was maintained when the brachial dilation was expressed as absolute diameter change (Deltamm; r = 0.51; P = 0.002) and when it was normalized (/s) to the mean shear rate (r = 0.50; P = 0.002). 4. The present study demonstrates a relationship between peak FMD in the brachial artery and plasma levels of NO(x) in young men and women. This relationship suggests that brachial FMD and/or plasma NO(x) may be used as markers of peripheral endothelial function. PMID:17973870

Casey, Darren P; Beck, Darren T; Braith, Randy W

2007-12-01

272

Thermal annealing of nitrite in gamma-irradiated tris\\/ethylenediamine\\/cobalt\\/III\\/ nitrate  

Microsoft Academic Search

The annealing of chemical radiation damage in 1 MGy60Co gamma irradiated tris-\\/ethylenediamine\\/cobalt\\/III\\/ nitrate has been studied at different temperatures between 100 and 150 °C. The nitrate moiety suffers very little decomposition and the damage is only partially removed under these conditions. The recovery rate is rapid in the initial period\\/up to 1 h\\/ and remains almost constant on further heating

D. Bhatta; P. G. Dalai; S. R. Mohanty

1984-01-01

273

Enzymatic interconversion of ammonia and nitrite: the right tool for the job.  

PubMed

Hydroxylamine oxidoreductase (HAO) from Nitrosomonas europaea normally catalyzes oxidation of NH(2)OH to NO(2)(-). This paper reports experiments in which HAO was thermodynamically poised to catalyze reduction of NO(2)(-) to NH(4)(+). HAO was found to catalyze the reduction of NO(2)(-) by methyl viologen monocation radical (MV(red)), displaying a hyperbolic dependence on NO(2)(-) concentration, with a k(cat1) of 6.8 ± 0.3 s(-1) and a K(m1) of 7.6 ± 0.9 mM. HAO also catalyzed the reduction of NH(2)OH by MV(red), with a hyperbolic dependence on NH(2)OH concentration, and a k(cat2) of 245 ± 3 s(-1) and a K(m2) of 6.8 ± 0.2 mM (k(cat1) and k(cat2) reflect the maximum number of electrons transferred from MV(red) per second). We had previously demonstrated that HAO catalyzes the reduction of NO by MV(red) to yield first NH(2)OH and then NH(4)(+). Thus, overall, HAO is seen to act like a cytochrome c nitrite reductase, which catalyzes the six-electron reduction of NO(2)(-) to NH(4)(+) by MV(red). In the presence of Ru(NH(3))(2+) (Ru(II)) and Ru(NH(3))(3+) (Ru(III)) at ratios exceeding 200:1, HAO exhibited no detectable Ru(II)-NO(2)(-) oxidoreductase activity, though such activity is thermodynamically favored. On the other hand, HAO could still catalyze the oxidation of NH(2)OH to NO by Ru(III) under these conditions. The oxidative process exhibited a hyperbolic dependence on NH(2)OH concentration, with a k(cat3) of 98 ± 3 s(-1) and a K(m3) of 5.2 ± 0.8 ?M. Finally, HAO was found not to catalyze the disproportionation of NH(2)OH, despite the thermodynamic favorability of such a process, and the apparent opportunity presented by the HAO structure. Mechanisms are proposed to explain all the kinetic data. PMID:20812758

Kostera, Joshua; McGarry, Jennifer; Pacheco, A Andrew

2010-09-13

274

Limited impact of free ammonia on Nitrobacter spp. inhibition assessed by chemical and molecular techniques.  

PubMed

Free ammonia has long been identified as a nitrite oxidation inhibitor. However, past attempts to use this compound to eliminate nitrite oxidation and thereby promote more efficient nitrogen removal strategies during biological wastewater treatment have often failed. Additionally, contradictory results exist in the literature where direct measurements of free ammonia inhibition of nitrite oxidation have been reported. In this study, suspended biomass samples (nitrifier enriched activated sludge) were collected from a bench scale nitrification reactor with Nitrobacter spp. as the dominant nitrite oxidizer and subjected to batch respirometric experiments designed to quantify free ammonia inhibition of nitrite oxidization. A variety of data including ammonia, nitrite, and nitrate conversion rates, oxygen consumption rates, and Nitrobacter ribosomal RNA transcript abundance, a molecular indicator of growth activity, were used to assess nitrite oxidation and growth activity. Both the traditional and molecular activity assessments indicated that free ammonia had a limited inhibitory effect on Nitrobacter spp. In fact, the pH changes necessary to induce high free ammonia concentrations (>10mg-N/L) had a demonstrably more important inhibiting effect on nitrite oxidation than free ammonia. In contrast, during high ammonia oxidizing activity (5.3mg-N/L/h), low nitrite oxidation rates (0.2mg-N/L/h) and severely impaired Nitrobacter spp. growth activity, indicated by a low abundance of the Nitrobacter spp. ribosomal gene transcript relative to the ribosomal gene (0.08), were measured. The findings suggest that pH changes and ammonia oxidizing bacteria activity are more important factors limiting Nitrobacter spp. mediated nitrite oxidation, rather than the free ammonia concentration. PMID:20153631

Hawkins, Shawn; Robinson, Kevin; Layton, Alice; Sayler, Gary

2010-02-13

275

Analytical techniques for quantifying (15)N/(14)N of nitrate, nitrite, total dissolved nitrogen and ammonium in environmental samples using a gas chromatograph equipped with a quadrupole mass spectrometer.  

PubMed

The measurement of (15)N concentrations in environmental samples requires sophisticated pretreatment devices and expensive isotope-ratio mass spectrometry (IRMS). This report describes the use of a gas chromatograph equipped with a quadrupole-type mass spectrometer (GC/MS) to measure (15)N concentrations of ammonium, nitrate, nitrite, and total dissolved nitrogen (TDN) in distilled water, a 2 M KCl solution and a 0.5 M K(2)SO(4) solution. The system measures nitrous oxide (N(2)O) that is ultimately converted from the target N compound, requiring no special apparatus such as a purge-and-trap pretreatment device. It uses a denitrifier lacking N(2)O reductase, which produces N(2)O from nitrate. Persulfate oxidation was applied to convert TDN to nitrate, while additional pretreatment with ammonia diffusion was required for ammonium prior to the persulfate oxidation. Up to 100 samples can be measured daily using the system. We can generally run (15)N measurements with only 1-10 mL of sample for each chemical species of N, a volume 1/10-1/100 times smaller than the amount necessary for conventional methods. Our method is useful for measuring (15)N with GC/MS, offering greater convenience than IRMS. PMID:21487202

Isobe, Kazuo; Suwa, Yuichi; Ikutani, Junko; Kuroiwa, Megumi; Makita, Tomoko; Takebayashi, Yu; Yoh, Muneoki; Otsuka, Shigeto; Senoo, Keishi; Ohmori, Masayuki; Koba, Keisuke

2011-01-01

276

Effect of Carbon\\/Nitrogen Ratio upon the Formation of Nitrate and Ammonia from Amino-acids in Soil  

Microsoft Academic Search

IN the course of an investigation into the decomposition of nitrogenous materials in the soil, we have in one experiment found a highly significant correlation between carbon\\/nitrogen ratio and the formation of both ammonia and nitrate from a series of amino-acids added to the soil.

O. Owen; G. W. Winsor; M. I. E. Long

1950-01-01

277

Disruption of narG, the Gene Encoding the Catalytic Subunit of Respiratory Nitrate Reductase, Also Affects Nitrite Respiration in Pseudomonas fluorescens YT101  

PubMed Central

The Pseudomonas fluorescens YT101 gene narG, which encodes the catalytic ? subunit of the respiratory nitrate reductase, was disrupted by insertion of a gentamicin resistance cassette. In the Nar? mutants, nitrate reductase activity was not detectable under all the conditions tested, suggesting that P. fluorescens YT101 contains only one membrane-bound nitrate reductase and no periplasmic nitrate reductase. Whereas N2O respiration was not affected, anaerobic growth with NO2 as the sole electron acceptor was delayed for all of the Nar? mutants following a transfer from oxic to anoxic conditions. These results provide the first demonstration of a regulatory link between nitrate and nitrite respiration in the denitrifying pathway.

Ghiglione, Jean-Francois; Philippot, Laurent; Normand, Philippe; Lensi, Robert; Potier, Patrick

1999-01-01

278

Evaluation of a solar intermittent refrigeration system for ice production operating with ammonia/lithium nitrate  

SciTech Connect

A novel solar intermittent refrigeration system for ice production developed in the Centro de Investigacion en Energia of the Universidad Nacional Autonoma de Mexico is presented. The system operates with the ammonia/lithium nitrate mixture. The system developed has a nominal capacity of 8 kg of ice/day. It consists of a cylindrical parabolic collector acting as generator-absorber. Evaporator temperatures as low as -11 C were obtained for several hours with solar coefficients of performance up to 0.08. It was found that the coefficient of performance increases with the increment of solar radiation and the solution concentration. A dependency of the coefficient of performance was not founded against the cooling water temperature. Also it was found that the maximum operating pressure increases meanwhile the generation temperature decreases with an increase of the solution concentration. (author)

Rivera, W.; Moreno-Quintanar, G.; Best, R. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, A.P. 34, 62580 Temixco, Mor. (Mexico); Rivera, C.O.; Martinez, F. [Facultad de Ingenieria Campus Coatzacoalcos, Universidad Veracruzana, Av. Universidad Km 7.5, 96530 Coatzacoalcos, Ver. (Mexico)

2011-01-15

279

Nitrate uptake and nitrite release by tomato roots in response to anoxia  

Microsoft Academic Search

Excised root systems of tomato plants (early fruiting stage, 2nd flush) were subjected to a gradual transition from normoxia to anoxia by sealing the hydroponic root medium while aeration was stopped. Oxygen level in the medium and respiration rate decreased and reached very low values after 12h of treatment, indicating that the tissues were anoxic thereafter. Nitrate loss from the

Philippe Morard; Jérôme Silvestre; Ludovic Lacoste; Edith Caumes; Thierry Lamaze

2004-01-01

280

Insights into high-temperature nitrogen cycling from studies of the thermophilic ammonia-oxidizing archaeon Nitrosocaldus yellowstonii. (Invited)  

Microsoft Academic Search

Our understanding of the nitrogen cycle has advanced significantly in recent years with the discovery of new metabolic processes and the recognition that key processes such as aerobic ammonia oxidation are more broadly distributed among extant organisms and habitat ranges. Nitrification, the oxidation of ammonia to nitrite and nitrate, is a key component of the nitrogen cycle and, until recently,

J. R. de la Torre

2010-01-01

281

THE SOLUBILITY OF URANYL COMPOUNDS IN ALKALI NITRATE-NITRITE MELTS  

Microsoft Academic Search

The solubilities of uranyl nitrate hexahydrate and anhydrous uranyl ; sulfate were measured in NaNOâ NaNO, and NaNOâKNOâ eutectic ; mixtures at temperatures ranging from 200 to 330 deg C. It seems that, even at ; the lowest temperature, both compounds decompose to UOâ (or a sodium ; uranate) the solubility of which is negligible (probably less than 0.02% U).

J. R. Findlay; J. N. Gregory

1954-01-01

282

Effect of 6-months of physical exercise on the nitrate/nitrite levels in hypertensive postmenopausal women  

PubMed Central

Background Evidences have showed that the incidence of arterial hypertension is greater in postmenopausal women as compared to premenopausal. Physical inactivity has been implicated as a major contributor to weight gain and abdominal obesity in postmenopausal women and the incidence of cardiovascular disease increases dramatically after menopause. Additionally, more women than men die each year of coronary heart disease and are twice as likely as men to die within the first year after a heart attack. A healthy lifestyle has been strongly associated with the regular physical activity and evidences have shown that physically active subjects have more longevity with reduction of morbidity and mortality. Nitric oxide (NO) produced by endothelial cells has been implicated in this beneficial effect with improvement of vascular relaxing and reduction in blood pressure in both laboratory animals and human. Although the effect of exercise training in the human cardiovascular system has been largely studied, the majority of these studies were predominantly conducted in men or young volunteers. Therefore, the aim of this work was to investigate the effects of 6 months of dynamic exercise training (ET) on blood pressure and plasma nitrate/nitrite concentration (NOx-) in hypertensive postmenopausal women. Methods Eleven volunteers were submitted to the ET consisting in 3 days a week, each session of 60 minutes during 6 months at moderate intensity (50% of heart rate reserve). Anthropometric parameters, blood pressure, NOx- concentration were measured at initial time and after ET. Results A significant reduction in both systolic and diastolic blood pressure values was seen after ET which was accompanied by markedly increase of NOx- levels (basal: 10 ± 0.9; ET: 16 ± 2 ?M). Total cholesterol was significantly reduced (basal: 220 ± 38 and ET: 178 ± 22 mg/dl), whereas triglycerides levels were not modified after ET (basal: 141 ± 89 and ET: 147 ± 8 mg/dl). Conclusion Our study shows that changing in lifestyle promotes reduction of arterial pressure which was accompanied by increase in nitrite/nitrate concentration. Therefore, 6-months of exercise training are an important approach in management arterial hypertension and play a protective effect in postmenopausal women.

Zaros, Pedro R; Pires, Carla EM Romero; Bacci, Mauricio; Moraes, Camila; Zanesco, Angelina

2009-01-01

283

Quantification and modeling of nitrate consumption, and nitrous oxide and nitrite production during push-pull tracer tests  

NASA Astrophysics Data System (ADS)

Field quantitative estimation of reaction kinetics is required to enhance our understanding of biogeochemical reactions in aquifers and to model the different element production/consumption. In this study, we quantify kinetics of nitrate consumption and by-products formation (nitrites and nitrous oxide) during autotrophic denitrification using push-pull tracer tests in a fractured crystalline aquifer (Ploemeur, French Brittany). Previous studies (Tarits et al., 2006) have shown that this very heterogeneous aquifer was characterized by the occurrence of an autotrophic denitrification reaction related to pyrite bearing fractures. Reactivity assessment by push-pull tests consists in injecting a well known solution composed of a reactive (NO3-) and a non reactive tracer (Br-) in a borehole (push phase). After a time lag the solution is pumped (pull phase) from the same borehole to obtain breakthrough curves. Comparison of the breakthrough curves of both tracers provides the consumed mass. Comparison of Br- and NO3- breakthrough curves shows that 10 % of the injected nitrate molar mass was transformed during the 12 hours experiment (2% in NO2-, 1% in N2O and the rest in N2 and NO). This experiment shows that push pull tests are reliable to assess autotrophic denitrification reaction by providing an in situ quantification of nitrate reduction and by-products formation. Similar results with comparable kinetics are obtained from laboratory experiments in reactors. To model the whole denitrification reaction, we extend the simplified analytical solution developed by Haggerty et al. (1998) through a first order reaction chain for push pull experiments analysis allowing the estimation of kinetic parameters for each reaction step. Then we assess the ability of this reaction chain to model biogeochemical reactions by comparing it to our experimental results. Good fit between model and experimental results indicate the possibility to consider the complete denitrification process as a sequence of first order reactions. As expected the estimated constant k1 for nitrates is the main limiting factor. Thus, biogeochemical reactions such as denitrification may be efficiently modeled as a first order reaction chain. Haggerty, R., Schroth, M.H. and Istok, J.D., 1998. Simplified method of "push-pull" test data analysis for determining in situ reaction rate coefficients. Ground Water, 36(2): 314-324. Tarits, C. et al., 2006. Oxido-reduction sequence related to flux variations of groundwater from a fractured basement aquifer (Ploemeur area, France). Applied Geochemistry, 21(1): 29-47

Boisson, A.; De Anna, P.; Bour, O.; Le Borgne, T.; Aquilina, L.

2011-12-01

284

Discrimination between structurally related ligands nitrate and nitrite controls autokinase activity of the NarX transmembrane signal transducer of Escherichia coli K-12  

Microsoft Academic Search

Summary Anaerobic respiratory gene expression in Escherichia coli is differentially controlled by nitrate and nitrite through dual interacting two-component regulatory systems. The NarX sensor is one of two membrane- spanning sensor kinases that control the phosphory- lation state of two DNA-binding response regulators. We have studied NarX autophosphorylation in crude membrane preparations from cells that overexpress NarX protein. The low

Stanly B. Williams; Valley Stewart

1997-01-01

285

The spoilage flora of vacuum-packaged, sodium nitrite or potassium nitrate treated, cold-smoked rainbow trout stored at 4°C or 8°C  

Microsoft Academic Search

The spoilage flora of vacuum-packaged, salted, cold-smoked rainbow trout fillets, with or without the addition of nitrate or nitrite, stored at 4°C and 8°C, was studied. Of 620 isolates, lactic acid bacteria were the major fraction (76%), predominating in all samples of spoiled product. However, the phenotypical tests used were insufficient to identify the lactic acid bacteria to the species

Ulrike Lyhs; Johanna Björkroth; Eija Hyytiä; Hannu Korkeala

1998-01-01

286

Determination of nitric oxide metabolites, nitrate and nitrite, in Anopheles culicifacies mosquito midgut and haemolymph by anion exchange high-performance liquid chromatography: plausible mechanism of refractoriness  

Microsoft Academic Search

BACKGROUND: The diverse physiological and pathological role of nitric oxide in innate immune defenses against many intra and extracellular pathogens, have led to the development of various methods for determining nitric oxide (NO) synthesis. NO metabolites, nitrite (NO2-) and nitrate (NO3-) are produced by the action of an inducible Anopheles culicifacies NO synthase (AcNOS) in mosquito mid-guts and may be

Arun Sharma; Kamaraju Raghavendra; Tridibesh Adak; Aditya P Dash

2008-01-01

287

Maternal characteristics associated with the dietary intake of nitrates, nitrites, and nitrosamines in women of child-bearing age: a cross-sectional study  

Microsoft Academic Search

BACKGROUND: Multiple N-nitroso compounds have been observed in animal studies to be both mutagenic and teratogenic. Human exposure to N-nitroso compounds and their precursors, nitrates and nitrites, can occur through exogenous sources, such as diet, drinking water, occupation, or environmental exposures, and through endogenous exposures resulting from the formation of N-nitroso compounds in the body. Very little information is available

John S Griesenbeck; Jean D Brender; Joseph R Sharkey; Michelle D Steck; John C Huber Jr; Antonio A Rene; Thomas J McDonald; Paul A Romitti; Mark A Canfield; Peter H Langlois; Lucina Suarez

2010-01-01

288

Dynamics of nitrate and nitrite content during storage of home-made and small-scale industrially produced raw vegetable juices and their dietary intake  

Microsoft Academic Search

The influence of storage conditions on nitrate and nitrite contents, pH, and total viable bacterial count of raw vegetable juices was studied. Three different types of juices from an Estonian small-scale producer and five different types of home-made juices were analysed. Analyses were performed immediately after opening the commercial juice packages and immediately after preparation of a home-made juice. Additionally,

T. Tamme; M. Reinik; T. Püssa; M. Roasto; K. Meremäe; A. Kiis

2010-01-01

289

A boundary-layer model of a parallel-plate electrochemical reactor for the destruction of nitrates and nitrites in alkaline waste solutions  

SciTech Connect

Electrochemical processes appear to be attractive for treating low level nuclear wastes. The development of a simple divided electrochemical-cell model operating in a batch mode, used for the reduction of nitrates and nitrites from nuclear wastes, is presented. This model, based on a boundary-layer approach, is simple and yet encompasses the key features of a previously developed distributed-parameter model that includes diffusion, migration, and convection as the flux components. Because it dramatically reduces computation time, this boundary-layer model is well suited for use in a complex interactive flowsheet model and for optimization studies. The boundary-layer model is sued to predict partial current densities, reservoir concentrations, and off-gas compositions as a function of time. Good agreement between simulated and experimental data (i.e., nitrate and nitrite concentrations and off-gas compositions) is observed over the course of a batch run. In addition, a comparison with a rigorous distributed-parameter model is made to illustrate the accuracy and robustness of this model. The results of selected case studies are shown, and a preliminary batch optimization is carried out to show how the model can be used to maximize the destruction of nitrates and nitrites.

Prasad, S.; Weidner, J.W.; Farell, A.E. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemical Engineering

1995-11-01

290

Fluidic automation of nitrate and nitrite bioassays in whole blood by dissolvable-film based centrifugo-pneumatic actuation.  

PubMed

This paper demonstrates the full centrifugal microfluidic integration and automation of all liquid handling steps of a 7-step fluorescence-linked immunosorbent assay (FLISA) for quantifying nitrate and nitrite levels in whole blood within about 15 min. The assay protocol encompasses the extraction of metered plasma, the controlled release of sample and reagents (enzymes, co-factors and fluorescent labels), and incubation and detection steps. Flow control is implemented by a rotationally actuated dissolvable film (DF) valving scheme. In the valves, the burst pressure is primarily determined by the radial position, geometry and volume of the valve chamber and its inlet channel and can thus be individually tuned over an extraordinarily wide range of equivalent spin rates between 1,000 RPM and 5,500 RPM. Furthermore, the vapour barrier properties of the DF valves are investigated in this paper in order to further show the potential for commercially relevant on-board storage of liquid reagents during shelf-life of bioanalytical, ready-to-use discs. PMID:24064595

Nwankire, Charles E; Chan, Di-Sien S; Gaughran, Jennifer; Burger, Robert; Gorkin, Robert; Ducrée, Jens

2013-08-26

291

AMMONIA  

EPA Science Inventory

This document summarizes the available information on ammonia as it relates to its effects on man and his environment. Ammonia is a ubiquitous substance and is known widely as a household cleaning agent and as a fertilizer. It plays an important role in the nitrogen cycle--in the...

292

Ammonia-forming cytochrome c nitrite reductase from Sulfurospirillum deleyianum is a tetraheme protein: new aspects of the molecular composition and spectroscopic properties.  

PubMed

Ammonia-forming cytochrome c nitrite reductase from Sulfurospirillum deleyianum contains four covalently bound heme c groups/55 kDa subunit as determined by atomic absorption spectroscopy and the pyridine Fe(II)-hemochrome technique. Nitrite reductase was isolated from the membrane fraction as a monomer (M(r) 55 +/- 2 kDa) and as a heterooligomeric complex. Both the monomeric and the complex form of the enzyme exhibited a high specific activity, with up to 1050 mumol NO2-min-1 mg-1. The complex was built from four 55 kDa units and contained a 22 kDa c-type cytochrome which was absent in the monomeric form. EPR spectra of the complex displayed a prominent feature at g 4.83 (baseline crossing). This resonance, which was not observed in the spectra of the monomeric nitrite reductase, was assigned to the 22 kDa c-type cytochrome subunit. Identical results were obtained for the enzyme from Wolinella succinogenes which had been reinvestigated for comparison. PMID:7999130

Schumacher, W; Hole, U; Kroneck, P M

1994-11-30

293

Role of nitrite in the induction of nitrate reductase activity in barley leaves  

SciTech Connect

High levels of nitrate reductase activity (NRA) were induced in detached leaves of 8-day-old barley (Hordeum vulgare L.) seedlings when supplied with NO/sub 2//sup -/ in the induction solutions. At similar N flux, the level of the enzyme activity induced by NO/sub 2//sup -/ was about one-half of that induced by NO/sub 3//sup -/. Significant levels of NO/sub 3//sup -/ accumulated in NO/sub 2//sup -/-fed leaves. Traces of NO/sub 3//sup -/ (0.6%) were detected in solutions of reagent grade KNO/sub 2/. However, the amount of NO/sub 3//sup -/ absorbed from the NO/sub 2//sup -/ solutions was only one-tenth of that accumulated in the leaves during the induction period, showing the actual conversion of NO/sub 2//sup -/ to NO/sub 3//sup -/ within the leaf. When the NO/sub 3//sup -/ concentrations in the NO/sub 2//sup -/-fed leaves were plotted against NRA, a highly positive correlation was obtained. The results suggest that NO/sub 2//sup -/ induces NRA indirectly after being oxidized to NO/sub 3//sup -/ within the leaf.

Aslam, M.; Huffaker, R.C.

1986-04-01

294

Nitrogen Transformations and Diversity of Ammonia-Oxidizing Bacteria in a Desert Ephemeral Stream Receiving Untreated Wastewater  

Microsoft Academic Search

Levels of inorganic nitrogen species (ammonia, nitrite, and nitrate), ammonia oxidation potential (AOP), and diversity of\\u000a ammonia-oxidizing bacteria (AOB) were studied in the sediments of a 50-km-long segment of an ephemeral stream in the Negev\\u000a desert, receiving untreated wastewater. Water analysis in downstream sampling points showed reductions of 91.7% in biological\\u000a oxygen demand, 87.7% in chemical oxygen demand, 73.9% in

Roey Angel; Lior Asaf; Zeev Ronen; Ali Nejidat

2010-01-01

295

Dairy slurry application method impacts ammonia emission and nitrate in no-till corn silage.  

PubMed

Reducing ammonia (NH3) emissions through slurry incorporation or other soil management techniques may increase nitrate (NO3) leaching, so quantifying potential losses from these alternative pathways is essential to improving slurry N management. Slurry N losses, as NH3 or NO3 were evaluated over 4 yr in south-central Wisconsin. Slurry (i.e., dairy cow [Bos taurus] manure from a storage pit) was applied each spring at a single rate (-75 m3 ha(-1)) in one of three ways: surface broadcast (SURF), surface broadcast followed by partial incorporation using an aerator implement (AER-INC), and injection (INJ). Ammonia emissions were measured during the 120 h following slurry application using chambers, and NO3 leaching was monitored in drainage lysimeters. Yield and N3 uptake of oat (Avena sativa L.), corn (Zea mays L.), and winter rye (Secale cereale L.) were measured each year, and at trial's end soils were sampled in 15- to 30-cm increments to 90-cm depth. There were significant tradeoffs in slurry N loss among pathways: annual mean NH3-N emission across all treatments was 5.3, 38.3, 12.4, and 21.8 kg ha(-1) and annual mean NO3-N leaching across all treatments was 24.1, 0.9, 16.9, and 7.3 kg ha' during Years 1, 2, 3, and 4, respectively. Slurry N loss amounted to 27.1% of applied N from the SURF treatment (20.5% as NH3-N and 6.6% as NO,-N), 23.3% from AER-INC (12.0% as NH3-N and 11.3% as NO3-N), and 9.19% from INJ (4.4% as NH3-N and 4.7% as NO3-N). Although slurry incorporation decreased slurry N loss, the conserved slurry N did not significantly impact crop yield, crop N uptake or soil properties at trial's end. PMID:21520745

Powell, J M; Jokela, W E; Misselbrook, T H

296

OBSERVABLE INDICATORS OF THE SENSITIVITY OF PM 2.5 NITRATE TO EMISSION REDUCTIONS, PART II: SENSITIVITY TO ERRORS IN TOTAL AMMONIA AND TOTAL NITRATE OF THE CMAQ-PREDICTED NONLINEAR EFFECT OF SO 2 EMISSION REDUCTIONS  

EPA Science Inventory

The inorganic aerosol system of sulfate, nitrate, and ammonium can respond nonlinearly to changes in precursor sulfur dioxide (SO2) emissions. The potential increase in nitrate, when sulfate is reduced and the associated ammonia is released, can negate the sulfate mass...

297

Effect of pH and HNO2 concentration on the activity of ammonia-oxidizing bacteria in a partial nitritation reactor.  

PubMed

Ammonia-oxidizing bacteria (AOB) are very sensitive to environmental conditions and wastewater treatment plant operational parameters. One of the most important factors affecting their activity is pH. Its effect is associated with: NH3/NH4(+) and HNO2/NO2(-) chemical equilibriums and biological reaction rates. The aim of this study was to quantify and model the effect of pH and free nitrous acid (FNA) concentration on the activity of AOB present in a lab-scale partial nitritation reactor. For this purpose, two sets of batch experiments were carried out using biomass from this reactor. Fluorescent in situ hybridization analysis showed that Nitrosomona eutropha and Nitrosomona europaea species were dominant in the partial nitritation reactor (>94%). The experimental results showed that FNA inhibits the AOB activity. This inhibition was properly modelled by the non-competitive inhibition function and the half inhibition constant value was determined as 1.32 mg HNO2-N L(-1). The optimal pH for these AOB was found to be in the range 7.4-7.8. The pH inhibitory effect was stronger at high pH values than at low pH values. Therefore, an asymmetric inhibition function was proposed to represent the pH effect on these bacteria. A combination of two sigmoidal functions was able to reproduce the experimental results obtained. PMID:23752393

Claros, J; Jiménez, E; Aguado, D; Ferrer, J; Seco, A; Serralta, J

2013-01-01

298

IL-1 beta does not cause neutrophil degranulation but does lead to IL-6, IL-8, and nitrite/nitrate release when used in patients with cancer.  

PubMed

The use of IL-1 in humans is associated with dose-limiting toxicity which resembles that of TNF-alpha or IL-2. Activation of neutrophils is thought to contribute to the toxicity caused by these two cytokines. We studied the effect of IL-1 in vivo on changes in neutrophil numbers and neutrophil degranulation as well as on the formation of neutrophil agonists, such as complement activation products, and on levels of TNF, IL-6, IL-8, and nitrite/nitrate (as a measure of nitric oxide production). Six patients with metastatic melanoma were treated with 3 ng/kg recombinant human IL-1 beta daily. One hour after the start of the 30-min IL-1 infusion, which caused mild cardiovascular toxicity, plasma levels of IL-6 reached a peak of 25 +/- 9 ng/L (mean +/- SEM), IL-8 reached a peak of 311 +/- 100 ng/L at 2 h, and nitrite/nitrate peaked after 10 h to 89 +/- 27 mumol/L. IL-1 did not induce significant changes in plasma levels of TNF or of the complement activation products C3a and C4b/c. Although IL-1 induced neutrophilia, levels of elastase and lactoferrin did not change. The failure of IL-1 to degranulate neutrophils was confirmed in an ex vivo model with whole blood culture in which doses of up to 100 microgram/L IL-1 beta or IL-1 alpha failed to induce significant elastase or lactoferrin release, whereas TNF, tested as a positive control, was able to do so. These results demonstrate that, unlike TNF, IL-1 does not cause neutrophil degranulation in man, despite its ability to cause neutrophilia and the rapid release of IL-6, IL-8, and nitrite/nitrate. PMID:8598489

Ogilvie, A C; Hack, C E; Wagstaff, J; van Mierlo, G J; Erenberg, A J; Thomsen, L L; Hoekman, K; Rankin, E M

1996-01-01

299

Molecular and catalytic properties of a novel cytochrome c nitrite reductase from nitrate-reducing haloalkaliphilic sulfur-oxidizing bacterium Thioalkalivibrio nitratireducens.  

PubMed

A highly active cytochrome c nitrite reductase from the haloalkaliphilic sulfur-oxidizing non-ammonifying bacterium Tv. nitratireducens strain ALEN 2 (TvNiR) was isolated and purified to apparent electrophoretic homogeneity. The enzyme catalyzes reductive conversion of nitrite and hydroxylamine to ammonia without release of any intermediates, as well as reduction of sulfite to sulfide. TvNiR also possesses peroxidase activity. In solution TvNiR exists as a stable hexamer with molecular mass of about 360kDa. Each TvNiR subunit with molecular mass of 64kDa contains, as defined from spectral properties and sequence analysis, eight c-type haems. Seven of them are coordinated by the characteristic CXXCH motifs for haem c binding, while one is bonded by the unique CXXCK motif. So far, this motif coordinating the catalytic haem was found only in bacterial cytochrome c nitrite reductases (ccNiRs). All the residues essential for catalysis in the known ccNiRs were also identified in TvNiR. However, TvNiR is only distantly related to known bacterial ammonifying dissimilatory ccNiRs, sharing no more than 20% homology. PMID:16500161

Tikhonova, Tamara V; Slutsky, Alvira; Antipov, Alexey N; Boyko, Konstantin M; Polyakov, Konstantin M; Sorokin, Dimitry Y; Zvyagilskaya, Renata A; Popov, Vladimir O

2006-02-09

300

The isolation of a hexaheme cytochrome from Desulfovibrio desulfuricans and its identification as a new type of nitrite reductase  

SciTech Connect

Desulfovibrio desulfuricans (ATCC 27774), a strictly anaerobic sulfate-reducing bacteria, is able to perform anaerobic nitrate respiration in which nitrate is first reduced to nitrite by the action of nitrate reductase, and nitrite reductase then catalyzes the six-electron reduction of nitrite to ammonia. The nitrite reductase was found to be a membrane-bound enzyme and has been purified to electrophoretic homogeneity. The purified enzyme has a minimal M/sub r/=66,000 as judged by sodium dodecyl sulfate gel electrophoresis and contains 6 c-type heme groups/molecule. Pure nitrite reductase exhibits a typical c-type cytochrome absorption spectrum with reduced..cap alpha..-band at 552.5 nm. NADH and NADPH do not function as direct electron donors for the nitrite reductase. Desulfovibrio vulgaris hydrogenase,however, is able to transfer electrons from H/sub 2/ to the nitrite reductase using FAD as the electron transfer mediator. The dithionite-reduced nitrite reductase was demonstrated to be auto-oxidizable even in the presence of potassium cyanide. On addition of nitrite, the dithionite-reduced enzyme is re-oxidized immediately. Hydroxylamine, however, can only partially reoxidize the reduced enzyme. Ascorbate reduces the enzyme to a limited extent and the partially reduced enzyme is neither auto-oxidizable by nitrite or hydroxylamine. Purified nitrite reductase has a pH optimum in the range of 8.0-9.5 and optimal activity at 57/sup o/C. Purified nitrite reductase also has hydroxylamine reductase activity, and the K/sub m/ for nitrite was determined to be 1.14 mM.

Liu, M.-C.; Peck, H.D., Jr.

1981-12-01

301

Purification of Vibrio fischeri nitrite reductase and its characterization as a hexaheme c-type cytochrome.  

PubMed

Dissimilatory nitrite reductase was isolated from anaerobically nitrate-grown Vibrio fischeri cells and purified to electrophoretic homogeneity. The enzyme catalyzes the six-electron reduction of nitrite to ammonia. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, under either nonreducing or reducing conditions, the purified nitrite reductase migrated as a single protein band of Mr 57,000. Gel filtration chromatography revealed a native molecular weight of 58,000, indicating the enzyme as isolated to be present in the monomeric form. Purified nitrite reductase exhibited typical c-type cytochrome absorption spectra with the reduced alpha-band at 552.5 nm. Heme content analysis using the purified preparation indicated the enzyme to contain 5.5 heme c groups per molecule. Iron analysis showed the presence of 5.62 g iron atoms per mole of enzyme and no nonheme irons were detected. These results clearly indicate that, similar to the dissimilatory nitrite reductases from Desulfovibrio desulfuricans, Wolinella succinogenes, and Escherichia coli, the V. fischeri nitrite reductase is a hexaheme c-type cytochrome. Amino acid composition of V. fischeri also revealed close similarities to those of the other three hexaheme nitrite reductases previously studied. Based on this information, it is concluded that the four ammonia-forming, dissimilatory nitrite reductases isolated to date represent a homologous group of proteins with the distinct property of being hexaheme c-type cytochromes. PMID:2833168

Liu, M C; Bakel, B W; Liu, M Y; Dao, T N

1988-04-01

302

Changes in Benthic Denitrification, Nitrate Ammonification, and Anammox Process Rates and Nitrate and Nitrite Reductase Gene Abundances along an Estuarine Nutrient Gradient (the Colne Estuary, United Kingdom)  

Microsoft Academic Search

Estuarine sediments are the location for significant bacterial removal of anthropogenically derived inorganic nitrogen, in particular nitrate, from the aquatic environment. In this study, rates of benthic denitrification (DN), dissimilatory nitrate reduction to ammonium (DNRA), and anammox (AN) at three sites along a nitrate concentration gradient in the Colne estuary, United Kingdom, were determined, and the numbers of functional genes

Liang F. Dong; Cindy J. Smith; Sokratis Papaspyrou; Andrew Stott; A. Mark Osborn; David B. Nedwell

2009-01-01

303

Nitrate to ammonia and ceramic (NAC) bench scale stabilization studies. Final technical progress report, May 1995--May 1996  

SciTech Connect

The Department of Energy (DOE) has large quantities of sodium-nitrate based liquid wastes. Around 1 billion liters of high level waste tank supernatant are present at Hanford, Savannah River Plant, Rocky Flats Plant, Idaho National Engineering Laboratory, and Oak Ridge National Laboratory. The largest quantity of these wastes is in the 149 single shell tanks at Hanford which hold up to 1 million gallons each. These tank waste are typically 4 to 5 molar in nitrate and contain radionuclides, various salts, and heavy metals. INEL high-level waste tank supernatant contains about 0.7 and 0.6 grams per liter of chromium and mercury, respectively. SRP high-level waste tank supernatant contains about 0.2 g/L of chromium. Other heavy metals could well be present at lower levels in theses tank wastes. The major components present in these wastes are summarized in Appendix A. These wastes are currently regulated and managed by the DOE. Under the Federal Facility Compliance Act (FFCA) DOE is subject to RCRA, which would apply to these tank supernatants. Stabilization of this waste is difficult because nitrates are very mobile. Additionally, vitrification of these wastes produces large quantities of hard-to-manage NO{sub x} emissions. The conversion of sodium nitrate to ammonia is discussed.

NONE

1996-05-01

304

Assessment of Nitrification in Distribution Systems of Waters with Elevated Ammonia Levels  

EPA Science Inventory

The objective of this work is to monitor ammonia, nitrite, and nitrate in drinking water from the distribution systems of four drinking water utilities in Illinois. A monthly drinking water distribution system water quality monitoring protocol for each water utility in Illinois h...

305

Survey of residual nitrite and nitrate in conventional and organic/natural/uncured/indirectly cured meats available at retail in the United States.  

PubMed

A survey of residual nitrite (NO(2)(-)) and nitrate (NO(3)(-)) in cured meats available at retail was conducted to verify concentrations in conventional (C) products and establish a baseline for organic/natural/uncured/indirectly cured (ONC) products. In this study, 470 cured meat products representing six major categories were taken from retail outlets in five major metropolitan cities across the United States. Random samples representing both C and ONC type products were analyzed for NO(2)(-) and NO(3)(-) content (ppm) using an ENO-20 high-performance liquid chromatography system equipped with a reverse phase column. Generally, there were no differences in NO(2)(-) concentrations between C and ONC meat categories, but a few ONC products surveyed in certain cities were lower in NO(3)(-) content. Pairwise comparisons between cities indicated that NO(2)(-) and NO(3)(-) contents of all C type products were not appreciably different, and the same was true for most ONC products. Numerical NO(2)(-) values were less variable than NO(3)(-) concentrations within each meat product category. NO(2)(-) concentrations were similar to those previously reported by Cassens ( Cassens , R. G. Residual nitrite in cured meat . Food Technol. 1997a , 51 , 53 - 55 ) in 1997. Residual NO(2)(-) and NO(3)(-) values in this study were numerically lower than those reported by NAS ( National Academy of Sciences . The Health Effects of Nitrate, Nitrite, and N-Nitroso Compounds ; National Academy Press : Washington, DC , 1981 ) in 1981. Data from this survey provide a benchmark of NO(2)(-) and NO(3)(-) concentrations for ONC products available at retail. PMID:22414374

Nuñez De González, Maryuri T; Osburn, Wesley N; Hardin, Margaret D; Longnecker, Michael; Garg, Harsha K; Bryan, Nathan S; Keeton, Jimmy T

2012-04-05

306

Annual uptake and distribution of N 15 -labelled ammonia and nitrate in young Jonathan\\/MM104 apple trees grown in solution cultures  

Microsoft Academic Search

Summary  By using N15-labelled calcium nitrate and ammonium sulphate, the uptake of ammonia and nitrate by young Jonathan\\/MM104 apple trees grown\\u000a in a glasshouse in water culture was determined. A batch of 4 trees was exposed to the appropriate tracer for seven days and\\u000a then sampled. This procedure was repeated at 4 weekly intervals during a 12-month period. The results show

V. O. Grasmanis; D. J. D. Nicholas

1971-01-01

307

Nitrates and nitrites in vegetables and vegetable-based products and their intakes by the Estonian population  

Microsoft Academic Search

The content of nitrates were determined in 1349 samples of vegetables and ready-made food in 2003–2004 as a part of the Estonian food safety monitoring programme and the Estonian Science Foundation grant research activities. The results of manufacturers’ analyses carried out for internal monitoring were included in the study. The highest mean values of nitrates were detected in dill, spinach,

T. Tamme; M. Reinik; M. Roasto; K. Juhkam; T. Tenno; A. Kiis

2006-01-01

308

Effects of repeated application of sulfadiazine-contaminated pig manure on the abundance and diversity of ammonia and nitrite oxidizers in the root-rhizosphere complex of pasture plants under field conditions.  

PubMed

In a field experiment, the impact of repeated application of the antibiotic sulfadiazine (SDZ)-contaminated pig manure was assessed on functional microbial communities involved in ammonia and nitrite oxidation in the root-rhizosphere complexes (RRCs) of diverse plants composing a pasture. We surveyed the abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) as well as Nitrobacter- and Nitrospira-like nitrite-oxidizing bacteria (NOB) by quantitative PCR (qPCR), and the diversity of amoA AOA and Nitrobacter-like nxrA amplicons using a cloning-sequencing approach. Whereas the first SDZ-contaminated manure application caused only slight effects on the investigated microbial communities and did not change the diversity and abundance pattern significantly, the second application of SDZ-contaminated manure induced an up to 15-fold increased ratio of AOA:AOB and a reduction of nrxA genes. The diversity of AOA amoA increased after the second application of SDZ-contaminated manure compared to the control treatment whereas a clear reduction of nrxA OTUs was visible in the same samples. The results indicate that the application of SDZ may principally affect nitrite oxidation by NOB and alternative pathways like nitrite reduction might be favored under these conditions. PMID:23420031

Ollivier, Julien; Schacht, Daniela; Kindler, Reimo; Groeneweg, Joost; Engel, Marion; Wilke, Berndt-Michael; Kleineidam, Kristina; Schloter, Michael

2013-02-14

309

Effects of 2-nitrooxy ethyl 2-amino 3-methylbutanoate gel on resistance exercise performance and blood nitrate/nitrite in resistance trained men.  

PubMed

Nitric oxide dietary supplements are popular within the sport community. Our recent work involving the oral intake of 2-nitrooxy ethyl 2-amino 3-methylbutanoate demonstrated an approximately 6.7% increase in circulating nitrate/nitrite. However, no measures of exercise performance were obtained. The present study used a topical form of this molecule to determine the impact on exercise performance and blood nitrate/nitrite. Fourteen resistance trained men (24 ± 1 years old) reported to the laboratory on 2 occasions to undergo exercise testing, which consisted of arm curl isometric force and muscular endurance (3 sets to fatigue using 80, 65, and 50% of 1 repetition maximum [1RM]: total of 9 sets). The gel (2-nitrooxy ethyl 2-amino 3-methylbutanoate; mixed in tea tree oil) or placebo (tea tree oil) was applied topically by the subjects for 7 days before each test day, with 7-10 days separating the randomly ordered conditions. Blood samples, arm circumference, and perceived "muscle pump" were taken before and immediately after exercise on both test days. The heart rate and perceived exertion were measured after each set. No statistically significant differences were noted between conditions for performance variables (p > 0.05). However, when using a load of 50% of 1RM, 6.2% more repetitions were performed when using the gel as compared with when using the placebo; 19.9% more repetitions were performed by 8 subjects noted to be "responders" to gel treatment. Blood lactate and muscle pump significantly increased with exercise (p < 0.0001) but were not different between conditions (p > 0.05). Minimal change was noted in nitrate/nitrite, and the heart rate and perceived exertion were nearly identical between conditions (p > 0.05). These findings indicate that 2-nitrooxy ethyl 2-amino 3-methylbutanoate gel has a modest (6.2%), nonstatistically significant effect on exercise performance, in particular when using a load of 50% 1RM-with greater benefit noted in selected individuals. Studies inclusive of a larger sample size are needed to extend these initial findings. PMID:21921823

Bloomer, Richard J; Alleman, Rick J; Cantrell, Greg S; Farney, Tyler M; Schilling, Brian K

2012-06-01

310

Synthesis of nano-structured polypyrrole\\/copper electrodes for nitrate and nitrite electroreductionReport submitted to the 5th International Workshop on Advanced Materials Science and Nanotechnology IWAMSN, Hanoi, 9–12 November 2010  

Microsoft Academic Search

Nanostructured polypyrrole film was synthesized onto a copper electrode in solutions of oxalic and salicylic acids and their buffers. The electrooxidation of pyrrole to form polypyrrole film and the electroreduction of nitrate and nitrite ions at synthesized Ppy modified copper electrodes (Ppy\\/Cu) in potassium chloride aqueous solutions were studied using chronoamperometry. The nanoporous structure of the synthesized Ppy films was

Thi Phuong Thoa Nguyen; Viet Thinh Nguyen; Nhat Nguyen Bui; Duong Kim Bao Do; Anh Minh Pham

2010-01-01

311

Distribution of Nitrosomonas-related ammonia-oxidizing bacteria and Nitrobacter-related nitrite-oxidizing bacteria in two full-scale biological nutrient removal plants.  

PubMed

The dominant nitrifying bacterial communities and nitrification performance of two biological nutrient removal plants were evaluated. Fluorescent in situ hybridization was used to detect and quantify the dominant nitrifying bacteria and polymerase chain reaction; cloning and sequence analysis of 16S rRNA genes was done for phylogenetic analysis. Fluorescent in situ hybridization-confocal scanning laser microscopy studies revealed the presence and dominance of Nitrosomonas-related ammonia-oxidizing bacteria (AOB) and Nitrobacter-related nitrite-oxidizing bacteria (NOB); however, a significant variation in AOB/NOB ratios was recorded. The plant with an overall higher AOB/NOB ratio (> or = 1.0) and dissolved oxygen concentration (1.8 to 2.5 mg/L) showed a higher nitrification rate. This study has also shown the co-existence and variation in phylogenetically diverse Nitrosomonas-related AOB and Nitrobacter-related NOB at these two plants. These dissimilar, distinct distribution patterns of nitrifying communities could be attributed to wastewater characteristics and the process configuration, which, in turn, would have also affected the nitrification performance of the systems. PMID:23697242

Ramdhani, Nishani; Kumari, Sheena; Bux, Faizal

2013-04-01

312

On the isotopic composition of the ammonia and the nitrate ion in rain  

Microsoft Academic Search

It is pointed out that rain does not remove all the nitrogen compounds ; from the air mass. Both ammonia and nitrogen oxides occur in the gas phase in ; equilibrium with the liquid phase. If the liquid phase is removed by ; gravitational pull, there is always the gaseous phase left. A fractionation ; effect may be expected, therefore,

Erik Eriksson

1958-01-01

313

Nitrogen - Ammonia/Nitrate/Nitrite. Water Quality Standards Criteria Summaries. A Compilation of State/Federal Criteria.  

National Technical Information Service (NTIS)

This digest is compiled to provide general information to the public as well as to Federal, State, and local officials. It contains excerpts from the individual Federal-State water quality standards establishing pollutant specific criteria for interstate ...

1990-01-01

314

Plant Nitrate Reductase Gene Fragments Enhance Nitrite Production in Activated Murine Macrophage Cell Lines. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

Nitrate reductase (NR) gene fragments (1.1 kb and 800 bp) from the barley plant were incorporated into pSV2neo and transfected by electroporation into a variety of cell lines of different functionality. Only transfected murine macrophage cell lines demons...

J. G. Bruno J. E. Parker J. L. Kiel

1994-01-01

315

Nitritation versus full nitrification of ammonium-rich wastewater: comparison in terms of nitrous and nitric oxides emissions.  

PubMed

The processes of nitritation and full nitrification of synthetic reject wastewater were compared in terms of N2O and NO emissions. Two lab-scale sequencing batch reactors (SBR1 and SBR2) were enriched with Nitrosomonas (ammonia-oxidizing bacteria) and Nitrobacter (nitrite-oxidizing bacteria), as shown by fluorescence in situ hybridization (FISH) and high-resolution 16S rRNA tag pyrosequencing. Stable conversion of ammonium to nitrite and nitrite to nitrate was achieved in SBR1 and SBR2 respectively. Biomass from SBR2 was added in SBR1 in order to achieve full nitrification. Under nitritation, 1.22% of the converted-N was emitted as N2O, and 0.066% as NO. During the transition from nitritation to full nitrification, effluent nitrite concentrations decreased but nitrogen oxides were emitted at levels similar to the nitritation period. Gas emissions decreased sharply under full nitrification conditions (0.54% N2O-N/converted-N; 0.021% NO-N/converted-N), probably as a result of the combined effect of lower nitrite and ammonium concentrations in the bioreactor. PMID:23665516

Rodriguez-Caballero, A; Ribera, A; Balcázar, J L; Pijuan, M

2013-04-13

316

Oxygen Regulates Tissue Nitrite Metabolism  

PubMed Central

Abstract Aims: Once dismissed as an inert byproduct of nitric oxide (NO) auto-oxidation, nitrite (NO2-) is now accepted as an endocrine reservoir of NO that elicits biological responses in major organs. While it is known that tissue nitrite is derived from NO oxidation and the diet, little is known about how nitrite is metabolized by tissue, particularly at intermediate oxygen tensions. We investigated the rates and mechanisms of tissue nitrite metabolism over a range of oxygen concentrations. Results: We show that the rate of nitrite consumption differs in each organ. Further, oxygen regulates the rate and products of nitrite metabolism. In anoxia, nitrite is reduced to NO, with significant formation of iron–nitrosyl proteins and S-nitrosothiols. This hypoxic nitrite metabolism is mediated by different nitrite reductases in each tissue. In contrast, low concentrations (?3.5??M) of oxygen increase the rate of nitrite consumption by shifting nitrite metabolism to oxidative pathways, yielding nitrate. While cytochrome P450 and myoglobin contribute in the liver and heart, respectively, mitochondrial cytochrome c oxidase plays a significant role in nitrite oxidation, which is inhibited by cyanide. Using cyanide to prevent artifactual nitrite decay, we measure metabolism of oral and intraperitoneally administered nitrite in mice. Innovation: These data provide insight into the fate of nitrite in tissue, the enzymes involved in nitrite metabolism, and the role of oxygen in regulating these processes. Conclusion: We demonstrate that even at low concentrations, oxygen is a potent regulator of the rate and products of tissue nitrite metabolism. Antioxid. Redox Signal. 17, 951–961.

Curtis, Erin; Hsu, Lewis L.; Noguchi, Audrey C.; Geary, Lisa

2012-01-01

317

Nitritation and denitrifying phosphorus removal via nitrite pathway from domestic wastewater in a continuous MUCT process.  

PubMed

Nitritation and denitrifying P removal under mode of nitritation and nitrification was investigated in continuous MUCT process treating domestic wastewater. Nitritation was established through short hydraulic retention time to 6 h and low dissolved oxygen concentration of 0.3-0.5 mg/L. Nitritation was stabilized for 95 days with average nitrite accumulation ratio over 90%. Ammonia and total nitrogen removal under nitritation reached 99% and 83%, respectively, much better than complete nitrification. Real-time quantitative PCR assays presented that cell numbers and percentages of ammonia oxidizing bacteria (AOB) population had a clear correlation with nitrite accumulation ratios. The highest percentage of AOB was 13% of total bacterial population. P removal was mainly completed by denitrifying P removal of about 90% occurring in anoxic zone. The P removal efficiency under nitritation was 30% higher than that under complete nitrification. Denitrifying P removal under nitritation was highly beneficial to the treatment of wastewater with limiting carbon source. PMID:23792758

Zeng, Wei; Wang, Xiangdong; Li, Boxiao; Bai, Xinlong; Peng, Yongzhen

2013-06-07

318

Part 1. Conducting polymer: Experimental aspects of piezoelectric quartz crystal oscillator and electrodeposited polyvinylferrocene (PVF) film system. Part 2. Voltammetric studies of nitrate and nitrite ions at rotating silver disk and electrochemical quartz crystal microbalance electrodes  

SciTech Connect

The experimental aspects of the electrochemical quartz crystal microbalance (EQCM) and the quartz crystal microbalance (QCM) techniques have been studied. These two techniques were applied to the investigation of polyvinylferrocene (PVF) film(s) on gold (Au) substrate. Additionally the EQCM and the Ag rotating disk electrodes were employed in tandem to investigate nitrate/nitrite reduction in basic and acidic media. In Chapter 2, a broad historical perspective of QCM, its application in the vacuum community, and the extended use in various liquids and hence the exploitation of the beneficial characteristics for electrochemical purposes (EQCM), are discussed. Chapter 3 treats the relatively new, yet established field of conducting polymer. Imbued in this chapter is the discussion of electrodeposition, rigidity determination, and characterization of PVF film. The studies of electroreduction of nitrate and nitrite ions are examined in chapters 4 and 5. Reduction in a basic solution is discussed in chapter 4, while chapter 5 looks at reduction in an acid medium.

Mensah, E.A.

1993-01-01

319

Comparison of pre-workout nitric oxide stimulating dietary supplements on skeletal muscle oxygen saturation, blood nitrate\\/nitrite, lipid peroxidation, and upper body exercise performance in resistance trained men  

Microsoft Academic Search

BACKGROUND: We compared Glycine Propionyl-L-Carnitine (GlycoCarn®) and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO2), blood nitrate\\/nitrite (NOx), lactate (HLa), malondialdehyde (MDA), and exercise performance in men. METHODS: Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws) and endurance (10 sets of bench press to muscular

Richard J Bloomer; Tyler M Farney; John F Trepanowski; Cameron G McCarthy; Robert E Canale; Brian K Schilling

2010-01-01

320

Nitrite, a new substrate for nitrogenase  

Microsoft Academic Search

The authors have examined the reactivity of the purified component proteins of Azotobacter vinelandii nitrogenase (Av1 and Av2) toward nitrate and nitrite. Nitrate has no effect on Hâ evolution or CâHâ reduction by nitrogenase and thus is neither a substrate nor an inhibitor. Nitrite dramatically inhibits Hâ evolution. This inhibition has two components, one irreversible and one reversible upon addition

Stephen A. Vaughn; Barbara K. Burgess

1989-01-01

321

Efficient electrochemical reduction of nitrate to nitrogen using Ti\\/IrO 2–Pt anode and different cathodes  

Microsoft Academic Search

Electrochemical reduction of nitrate using Fe, Cu, and Ti as cathodes and Ti\\/IrO2–Pt as anode in an undivided and unbuffered cell was studied. In the presence of appropriate amount of NaCl, both cathodic reduction of nitrate and anodic oxidation of the by-products of ammonia and nitrite were achieved by all cathodes under a proper condition. Both in the absence and

Miao Li; Chuanping Feng; Zhenya Zhang; Norio Sugiura

2009-01-01

322

Characterization of nitrite uptake in Arabidopsis thaliana: evidence for a nitrite-specific transporter.  

PubMed

Nitrite-specific plasma membrane transporters have been described in bacteria, algae and fungi, but there is no evidence of a nitrite-specific plasma membrane transporter in higher plants. We have used 13NO2 - to characterize nitrite influx into roots of Arabidopsis thaliana. Hydroponically grown Arabidopsis mutants, defective in high-affinity nitrate transport, were used to distinguish between nitrate and nitrite uptake by means of the short-lived tracers 13NO2 - and 13NO3 -. This approach allowed us to characterize a nitrite-specific transporter. The Atnar2.1-2 mutant, lacking a functional high-affinity nitrate transport system, is capable of nitrite influx that is constitutive and thermodynamically active. The corresponding fluxes conform to a rectangular hyperbola, exhibiting saturation at concentrations above 200 ?M (Km  = 185 ?M and Vmax  = 1.89 ?mol g(-1) FW h(-1) ). Nitrite influx via the putative nitrite transporter is not subject to competitive inhibition by nitrate but is downregulated after 6 h exposure to ammonium. These results signify the existence of a nitrite-specific transporter in Arabidopsis. This transporter enables Atnar2.1-2 mutants, which are incapable of sustained growth on low nitrate, to maintain significant growth on low nitrite. In wild-type plants, this nitrite flux may increase nitrogen acquisition and also participate in the induction of genes specifically induced by nitrite. PMID:23763619

Kotur, Zorica; Siddiqi, Yaeesh M; Glass, Anthony D M

2013-06-13

323

Semicarbazide-sensitive amine oxidase activity and total nitrite and nitrate concentrations in serum: novel biochemical markers for type 2 diabetes?  

PubMed

The aim of this study was to evaluate the activity of semicarbazide-sensitive amine oxidase (SSAO) and the total nitrite and nitrate (NO( x )) concentrations in serum from type 2 diabetic patients and control subjects in order to evaluate if they could be used as novel diabetic markers. We studied 38 type 2 diabetic patients and 35 control subjects. Serum samples from those subjects were evaluated by radiochemical methods for SSAO activity using (14)C-benzylamine. Serum NO( x ) concentrations were obtained as an index of nitric oxide production by the Griess reaction. Serum SSAO activity was higher in type 2 diabetic patients than in control group and serum SSAO in type 2 diabetic correlated with age, serum creatinine and total cholesterol. Serum NO( x ) levels in type 2 diabetic patients were also significantly higher than those in the control group. Serum NO( x ) levels in control group correlated with serum SSAO activity. In conclusion, the increase in the SSAO activity and NO( x ) levels observed in type 2 diabetic patients could be parameters to take in account and play relevant role in diabetes development. SSAO and NO( x ) are suggested as markers for prognostic of diabetes. PMID:18853098

Nunes, Sandra Fernanda; Figueiredo, Isabel Vitoria; Soares, Paulo João; Costa, Nuria Espriu; Lopes, Maria Celeste; Caramona, Maria Margarida

2008-10-14

324

COLORIMETRIC ASSAY OF SALIVARY NITRITE CONTENT  

Microsoft Academic Search

Salivary nitrate\\/nitrite concentration has often been used as a biomarker of human exposure to nitrate. A spectrophotometric method for estimation of nitrite in saliva is described. Nitrite (NO2 - ) is determined through formation of a reddish purple azo dye produced at pH 2.0 to 2.5 by coupling diazotized compound with 1-Naphthylamine. The method is suitable for the estimation of

Rodica Diaconu; Marieta Vasilov

325

Analytical properties of some commercially available nitrate reductase enzymes evaluated as replacements for cadmium in automated, semiautomated, and manual colorimetric methods for determination of nitrate plus nitrite in water  

USGS Publications Warehouse

A multiyear research effort at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) evaluated several commercially available nitrate reductase (NaR) enzymes as replacements for toxic cadmium in longstanding automated colorimetric air-segmented continuous-flow analyzer (CFA) methods for determining nitrate plus nitrite (NOx) in water. This research culminated in USGS approved standard- and low-level enzymatic reduction, colorimetric automated discrete analyzer NOx methods that have been in routine operation at the NWQL since October 2011. The enzyme used in these methods (AtNaR2) is a product of recombinant expression of NaR from Arabidopsis thaliana (L.) Heynh. (mouseear cress) in the yeast Pichia pastoris. Because the scope of the validation report for these new automated discrete analyzer methods, published as U.S. Geological Survey Techniques and Methods 5–B8, was limited to performance benchmarks and operational details, extensive foundational research with different enzymes—primarily YNaR1, a product of recombinant expression of NaR from Pichia angusta in the yeast Pichia pastoris—remained unpublished until now. This report documents research and development at the NWQL that was foundational to development and validation of the discrete analyzer methods. It includes: (1) details of instrumentation used to acquire kinetics data for several NaR enzymes in the presence and absence of known or suspected inhibitors in relation to reaction temperature and reaction pH; and (2) validation results—method detection limits, precision and bias estimates, spike recoveries, and interference studies—for standard- and low-level automated colorimetric CFA-YNaR1 reduction NOx methods in relation to corresponding USGS approved CFA cadmium-reduction (CdR) NOx methods. The cornerstone of this validation is paired sample statistical and graphical analysis of NOx concentrations from more than 3,800 geographically and seasonally diverse surface-water and groundwater samples that were analyzed in parallel by CFA-CdR and CFA enzyme-reduction methods. Finally, (3) demonstration of a semiautomated batch procedure in which 2-milliliter analyzer cups or disposable spectrophotometer cuvettes serve as reaction vessels for enzymatic reduction of nitrate to nitrite prior to analytical determinations. After the reduction step, analyzer cups are loaded onto CFA, flow injection, or discrete analyzers for simple, rapid, automatic nitrite determinations. In the case of manual determinations, analysts dispense colorimetric reagents into cuvettes containing post-reduction samples, allow time for color to develop, insert cuvettes individually into a spectrophotometer, and record percent transmittance or absorbance in relation to a reagent blank. Data presented here demonstrate equivalent analytical performance of enzymatic reduction NOx methods in these various formats to that of benchmark CFA-CdR NOx methods.

Patton, Charles J.; Kryskalla, Jennifer R.

2013-01-01

326

Metabolism of nitrate in fermented meats: the characteristic feature of a specific group of fermented foods.  

PubMed

Within the universe of food fermentation processes the multi-purpose use of nitrate and/or nitrite is a unique characteristic of meat fermentations. These curing agents play a decisive role in obtaining the specific sensory properties, stability and hygienic safety of products such as fermented sausages, ham and, more recently, emulsion type of sausages. The use of nitrate is the traditional method in curing processes and requires its reduction to reactive nitrite. Thus, nitrate reduction is the key event that is exclusively performed by microorganisms. Under controlled fermentation conditions starter cultures are used that contain staphylococci and/or Kocuria varians, which in addition to strongly affecting sensory properties exhibit efficient nitrate reductase activity. To obtain clean label products some plant sources of nitrate have been in use. When producing thermally treated sausages (e.g. of emulsion type), starter cultures are used that form nitrite before cooking takes place. Staphylococci reduce nitrite to ammonia after nitrate has been consumed. K. varians is devoid of nitrite reductase activity. Nitrate and nitrite reductases are also present in certain strains of lactobacilli. It was shown that their application as starter cultures warrants efficient activity in sausages made with either nitrate or nitrite. NO is formed from nitrite in numerous chemical reactions among which disproportionation and reaction with reductants either added or endogenous in meat are of practical importance. Numerous nitrosation and nitrosylation reactions take place in the meat matrix among which the formation of nitrosomyoglobin is of major sensory importance. Safety considerations in meat fermentation relate to the safe nature of the starter organisms and to the use of nitrate/nitrite. Staphylococci ("micrococci") in fermented meat have a long tradition in food use but have not received the QPS status from the EFSA. They require, therefore, thorough assessment with regard to toxigenicity and pathogenicity determinants as well as presence of transferable antibiotic resistance. Nitrate and nitrite are still considered basically undesired in food. The main objections are based on their potential to form nitrosamines with carcinogenic potential. In view of new results from intensive research of NO, potential risks are opposed by positive effects on human health. PMID:22202868

Hammes, Walter P

2011-07-07

327

Genetic regulation of nitrate assimilation in Klebsiella pneumoniae M5al.  

PubMed Central

We isolated Mu dI1734 insertion mutants of Klebsiella pneumoniae that were unable to assimilate nitrate or nitrite as the sole nitrogen source during aerobic growth (Nas- phenotype). The mutants were not altered in respiratory (anaerobic) nitrate and nitrite reduction or in general nitrogen control. The mutations were linked and thus defined a single locus (nas) containing genes required for nitrate assimilation. beta-Galactosidase synthesis in nas+/phi(nas-lacZ) merodiploid strains was induced by nitrate or nitrite and was inhibited by exogenous ammonia or by anaerobiosis. beta-Galactosidase synthesis in phi(nas-lacZ) haploid (Nas-) strains was nearly constitutive during nitrogen-limited aerobic growth and uninducible during anaerobic growth. A general nitrogen control regulatory mutation (ntrB4) allowed nitrate induction of phi(nas-lacZ) expression during anaerobic growth. This and other results suggest that the apparent anaerobic inhibition of phi(nas-lacZ) expression was due to general nitrogen control, exerted in response to ammonia generated by anaerobic (respiratory) nitrate reduction.

Cali, B M; Micca, J L; Stewart, V

1989-01-01

328

A computational model for nitric oxide, nitrite and nitrate biotransport in the microcirculation: effect of reduced nitric oxide consumption by red blood cells and blood velocity  

PubMed Central

Bioavailability of vasoactive endothelium-derived nitric oxide (NO) in vasculature is a critical factor in regulation of many physiological processes. Consumption of NO by RBC plays a crucial role in maintaining NO bioavailability. Recently, Deonikar et al (Deonikar and Kavdia, 2009b) reported a effective NO-RBC reaction rate constant of 0.2×105 M?1s?1 that is ~7 times lower than the commonly used NO-RBC reaction rate constant of 1.4×105 M?1s?1. To study the effect of lower NO-RBC reaction rate constant and nitrite and nitrate formation (products of NO metabolism in blood), we developed a 2D mathematical model of NO biotransport in 50 and 200 ?m ID arterioles to calculate NO concentration in radial and axial direction in the vascular lumen and vascular wall of the arterioles. We also simulated the effect of blood velocity on NO distribution in the arterioles to determine whether NO can be transported to downstream locations in the arteriolar lumen. The results indicate that lowering the NO-RBC reaction rate constant increased the NO concentration in the vascular lumen as well as the vascular wall. Increasing the velocity also led to increase in NO concentration. We predict increased NO concentration gradient along the axial direction with an increase in the velocity. The predicted NO concentration were 281–1163 nM in the smooth muscle cell layer for 50 ?m arteriole over the blood velocity range of 0.5–4 cm/s for kNO-RBC of 0.2×105 M?1 s?1, which are much higher than the reported values from earlier mathematical modeling studies. The NO concentrations are similar to the experimentally measured vascular wall NO concentration range of 300–1000 nM in several different vascular beds. The results are significant from the perspective that the downstream transport of NO is possible under right circumstances.

Deonikar, Prabhakar; Kavdia, Mahendra

2010-01-01

329

Analysis of nitrate in food extracts using a thermostable formate linked nitrate reductase enzyme system  

Microsoft Academic Search

A method for reduction of nitrate to nitrite for determination of nitrate is described, using a thermostable formate linked nitrate reductase enzyme system (FLNR). The reduction of nitrate to nitrite was found to be quantitative in water and in various food samples containing nitrate. The method is suggested as an alternative for the cadmium reduction method.

Sigurður Baldursson; Jakob K. Kristjánsson

1990-01-01

330

Nitrate, bacteria and human health  

Microsoft Academic Search

Nitrate is generally considered a water pollutant and an undesirable fertilizer residue in the food chain. Research in the 1970s indicated that, by reducing nitrate to nitrite, commensal bacteria might be involved in the pathogenesis of gastric cancers and other malignancies, as nitrite can enhance the generation of carcinogenic N-nitrosamines. More recent studies indicate that the bacterial metabolism of nitrate

Eddie Weitzberg; Jeff A. Cole; Nigel Benjamin; Jon O. Lundberg

2004-01-01

331

Abiotic nitrogen fixation on terrestrial planets: reduction of NO to ammonia by FeS.  

PubMed

Understanding the abiotic fixation of nitrogen and how such fixation can be a supply of prebiotic nitrogen is critical for understanding both the planetary evolution of, and the potential origin of life on, terrestrial planets. As nitrogen is a biochemically essential element, sources of biochemically accessible nitrogen, especially reduced nitrogen, are critical to prebiotic chemistry and the origin of life. Loss of atmospheric nitrogen can result in loss of the ability to sustain liquid water on a planetary surface, which would impact planetary habitability and hydrological processes that shape the surface. It is known that NO can be photochemically converted through a chain of reactions to form nitrate and nitrite, which can be subsequently reduced to ammonia. Here, we show that NO can also be directly reduced, by FeS, to ammonia. In addition to removing nitrogen from the atmosphere, this reaction is particularly important as a source of reduced nitrogen on an early terrestrial planet. By converting NO directly to ammonia in a single step, ammonia is formed with a higher product yield (~50%) than would be possible through the formation of nitrate/nitrite and subsequent conversion to ammonia. In conjunction with the reduction of NO, there is also a catalytic disproportionation at the mineral surface that converts NO to NO? and N?O. The NO? is then converted to ammonia, while the N?O is released back in the gas phase, which provides an abiotic source of nitrous oxide. PMID:22283408

Summers, David P; Basa, Ranor C B; Khare, Bishun; Rodoni, David

2012-01-27

332

Revised minimum nitrite concentration for ESP  

SciTech Connect

Nitrite is to be used to inhibit pitting corrosion during Extended Sludge Processing (ESP) at the Savannah River Plant. The required nitrite concentrations are expressed as a function of the slurries` nitrate ion concentration and temperature. In the most dilute slurries, the nitrite inhibitor requirement is independent of the nitrate ion concentration and depends only on the temperature of the waste. The nitrate-independent concentration ensures that there is sufficient inhibitor, in sludge slurries whose nitrate has been depleted by radiolysis, to prevent pitting corrosion induced by other corrosive anions (e.g., sulfate and chloride). The threshold nitrate concentration at which the nitrite level is expressed as a function only of temperature is 0.02 M.

Zapp, P.E.

1992-10-26

333

Microbial reduction of chromate in the presence of nitrate by three nitrate respiring organisms.  

PubMed

A major challenge for the bioremediation of toxic metals is the co-occurrence of nitrate, as it can inhibit metal transformation. Geobacter metallireducens, Desulfovibrio desulfuricans, and Sulfurospirillum barnesii are three soil bacteria that can reduce chromate [Cr(VI)] and nitrate, and may be beneficial for developing bioremediation strategies. All three organisms respire through dissimilatory nitrate reduction to ammonia (DNRA), employing different nitrate reductases but similar nitrite reductase (Nrf). G. metallireducens reduces nitrate to nitrite via the membrane bound nitrate reductase (Nar), while S. barnesii and D. desulfuricans strain 27774 have slightly different forms of periplasmic nitrate reductase (Nap). We investigated the effect of DNRA growth in the presence of Cr(VI) in these three organisms and the ability of each to reduce Cr(VI) to Cr(III), and found that each organisms responded differently. Growth of G. metallireducens on nitrate was completely inhibited by Cr(VI). Cultures of D. desulfuricans on nitrate media was initially delayed (48?h) in the presence of Cr(VI), but ultimately reached comparable cell yields to the non-treated control. This prolonged lag phase accompanied the transformation of Cr(VI) to Cr(III). Viable G. metallireducens cells could reduce Cr(VI), whereas Cr(VI) reduction by D. desulfuricans during growth, was mediated by a filterable and heat stable extracellular metabolite. S. barnesii growth on nitrate was not affected by Cr(VI), and Cr(VI) was reduced to Cr(III). However, Cr(VI) reduction activity in S. barnesii, was detected in both the cell free spent medium and cells, indicating both extracellular and cell associated mechanisms. Taken together, these results have demonstrated that Cr(VI) affects DNRA in the three organisms differently, and that each have a unique mechanism for Cr(VI) reduction. PMID:23251135

Chovanec, Peter; Sparacino-Watkins, Courtney; Zhang, Ning; Basu, Partha; Stolz, John F

2012-12-17

334

Completely autotrophic nitrogen-removal over nitrite in lab-scale constructed wetlands: evidence from a mass balance study.  

PubMed

A mass-balance study was carried out to investigate the transformation of nitrogenous pollutants in vertical flow wetlands. Landfill leachate containing low BOD, but a high concentration of ammonia, was treated in four wetland columns under predominately aerobic conditions. Influent total nitrogen in the leachate consisted mainly of ammonia with less than 1% nitrate and nitrite, and negligible organic nitrogen. There was a substantial loss of total nitrogen (52%) in one column, whereas other columns exhibited zero to minor losses (<12%). Net nitrogen loss under study conditions was unexpected. Correlations between pH, nitrite and nitrate concentrations indicated the removal of nitrogen under study conditions did not follow the conventional, simplistic, chemistry of autotrophic nitrification. Through mass-balance analysis, it was found that CANON (Completely Autotrophic Nitrogen-removal Over Nitrite) was responsible for the transformation of nitrogen into gaseous form, thereby causing the loss of nitrogen mass. The results show that CANON can be native to aerobic engineered wetland systems treating wastewater that contains high ammonia and low BOD. PMID:17349669

Sun, Guangzhi; Austin, David

2007-03-08

335

Simultaneous determinations of nitrification and nitrate reduction in coastal sediments by a 15N dilution technique.  

PubMed Central

Nitrification, the oxidation of ammonia to nitrite and nitrate, and nitrate reduction by bacteria in coastal sediments of Mangoku-Ura and Odawa Bay were simultaneously determined by a 15N dilution technique. In muddy sediments of Mangoku-Ura, nitrate reduction proceeded at a rate of 10(-2) to 10 X 10(-2) microgram-atoms of N/g per h. Nitrification was far less intensive. Denitrification, or N2 production from nitrate, accounted for about 30% of the nitrate reduction. A simultaneous occurrence of nitrification and nitrate reduction with a similar rate of 10(-2) microgram-atoms of N/g per h was demonstrated in sandy sediment collected from a Zostera bed of Odawa Bay.

Koike, I; Hattori, A

1978-01-01

336

Evolution of nitrate reductase: molecular and structural variations on a common function.  

PubMed

The biological transformation of nitrogen oxyanions is widespread in nature and gives rise to a robust biogeochemical cycle. The first step in nitrate reduction is carried out by the enzyme nitrate reductase (NR). Although NR always catalyzes the same chemical reaction (conversion of nitrate into nitrite), its location in the cell, structure, and function are organism-dependent. We use protein sequence data to determine phylogenetic relationships and to examine similarities in structure and function. Three distinct clades of NR are apparent: the eukaryotic assimilatory NR (Euk-NR) clade, the membrane-associated prokaryotic NR (Nar) clade, and a clade that includes both the periplasmic NR (Nap) and prokaryotic assimilatory NR (Nas). The high degree of sequence similarity and a phylogenetic distribution that follows taxonomic classification suggest a monophyletic origin for the Euk-NR early on in the evolution of eukaryotic cells. In contrast, sequence conservation, phylogenetic analysis, and physiology suggest that both Nar and Nap were acquired by horizontal gene transfer. Nap and Nas share a lesser degree of similarity, with Nap a subclade of Nas. Nap from strict anaerobic bacteria such as Desulfovibrio desulfuricans is ancestral to facultative species and may provide an evolutionary link between Nap and Nas. We observed conserved binding sites for molybdenum and pterin cofactors in all four proteins. In pathways involving Euk-NR, Nas, and Nar, for which ammonia is the end product, nitrite is reduced to ammonia by a siroheme nitrite reductase. Nap, however, is coupled to a pentaheme nitrite reductase. In denitrification, whether Nar or Nap is involved, nitrite is reduced to nitric oxide by either a cytochrome cd1 or a copper-containing nitrite reductase. This complexity underscores the importance of nitrate reduction as a key biological process. PMID:11921398

Stolz, John F; Basu, Partha

2002-03-01

337

The Exposure of Humans to Nitrite  

Microsoft Academic Search

Although nitrate is more abundant than nitrite in food and the environment in general, it requires reduction by, for instance, bacterial or plant enzymes before it is involved in the nitrosation of amines or amides. Part of the exposure of humans to nitrite arises from its use as a food additive where it performs a very useful function in protecting

C. L. Walters

1980-01-01

338

Nitrite in feed: From Animal health to human health  

Microsoft Academic Search

Nitrite is widely consumed from the diet by animals and humans. However the largest contribution to exposure results from the in vivo conversion of exogenously derived nitrate to nitrite. Because of its potential to cause to methaemoglobin (MetHb) formation at excessive levels of intake, nitrite is regulated in feed and water as an undesirable substance. Forages and contaminated water have

Andrew Cockburn; Gianfranco Brambilla; Maria-Luisa Fernández; Davide Arcella; Luisa R. Bordajandi; Bruce Cottrill; Carlos van Peteghem; Jean-Lou Dorne

339

Thermochemical nitrate destruction  

DOEpatents

A method is disclosed for denitrification of nitrates and nitrates present in aqueous waste streams. The method comprises the steps of (1) identifying the concentration nitrates and nitrites present in a waste stream, (2) causing formate to be present in the waste stream, (3) heating the mixture to a predetermined reaction temperature from about 200.degree. C. to about 600.degree. C., and (4) holding the mixture and accumulating products at heated and pressurized conditions for a residence time, thereby resulting in nitrogen and carbon dioxide gas, and hydroxides, and reducing the level of nitrates and nitrites to below drinking water standards.

Cox, John L. (Richland, WA); Hallen, Richard T. (Richland, WA); Lilga, Michael A. (Richland, WA)

1992-01-01

340

Direct wet and dry deposition of ammonia, nitric acid, ammonium and nitrate to the Tampa Bay Estuary, FL, USA  

Microsoft Academic Search

The average total (wet plus dry) nitrogen deposition to the Tampa Bay Estuary was 7.3 (±1.3)kg-Nha?1yr?1 or 760 (±140)metric tons-Nyr?1 for August 1996–July 1999, estimated as a direct deposition rate to the 104,000-ha water surface. This nitrogen flux estimate accounted for ammonia exchange at the air–sea interface. The uncertainty estimate was based on measurement error. Wet deposition was 56% of

Noreen Poor; Ray Pribble; Holly Greening

2001-01-01

341

Molecular Control of Nitrate Reductase and Other Enzymes Involved in Nitrate Assimilation  

Microsoft Academic Search

Nitrate acts as both a nutrient and a signal in plants. Nitrate induces gene expression of enzymes for its metabolism into amino acids but also has other effects on plant metabolism and development. Familiar nitrate-induced enzymes are nitrate and nitrite reductases, nitrate transporters, glutamine synthetase, glutamate synthase, ferredoxin and ferredoxin NADP+ reductase. Microarray analysis of nitrate-stimulated gene expression has identified

Wilbur H. Campbell

342

Hydrogen anode for nitrate waste destruction. Revision 2  

SciTech Connect

Large quantities of radioactive and hazardous wastes have been generated from nuclear materials production during the past fifty years. Processes are under evaluation to separate the high level radioactive species from the waste and store them permanently in the form of durable solids. The schemes proposed will separate the high level radioactive components, cesium-137 and strontium-90, into a small volume for incorporation into a glass wasteform. The remaining low-level radioactive waste contain species such as nitrites and nitrates that are capable of contaminating ground water. Electrochemical destruction of the nitrate and nitrite before permanent storage has been proposed. Not only will the electrochemical processing destroy these species, the volume of the waste could also be reduced. The use of a hydrogen gas-fed anode and an acid anolyte in an electrochemical cell used to destroy nitrate was demonstrated. A mixed Na{sub 2}SO{sub 4}/H{sub 2}SO{sub 4} anolyte was shown to favor the nitrate cell performance, and the generation of a higher hydroxide ion concentration in the catholyte. The suggested scheme is an apparent method of sodium sulfate disposal and a possible means through which ammonia (to ammonium sulfate, fertilizer) and hydrogen gas could be recycled through the anode side of the reactor. This could result in a substantial savings in the operation of a nitrate destruction cell.

Hobbs, D.T. [Westinghouse Savannah River Co., Aiken, SC (United States); Kalu, E.E.; White, R.E. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemical Engineering

1996-02-10

343

21 CFR 181.34 - Sodium nitrite and potassium nitrite.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Sodium nitrite and potassium nitrite. 181.34...Prior-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium nitrite are...

2013-04-01

344

Influence of Nitrate on the Hanford 100D Area In Situ Redox Manipulation Barrier Longevity  

SciTech Connect

The purpose of this laboratory study is to determine the influence of nitrate on the Hanford 100D Area in situ redox manipulation (ISRM) barrier longevity. There is a wide spread groundwater plume of 60 mg/L nitrate upgradient of the ISRM barrier with lower nitrate concentrations downgradient, suggestive of nitrate reduction occurring. Batch and 1-D column experiments showed that nitrate is being slowly reduced to nitrite and ammonia. These nitrate reduction reactions are predominantly abiotic, as experiments with and without bactericides present showed no difference in nitrate degradation rates. Nitrogen species transformation rates determined in experiments covered a range of ferrous iron/nitrate ratios such that the data can be used to predict rates in field scale conditions. Field scale reaction rate estimates for 100% reduced sediment (16 C) are: (a) nitrate degradation = 202 {+-} 50 h (half-life), (b) nitrite production = 850 {+-} 300 h, and (c) ammonia production = 650 {+-} 300 h. Calculation of the influence of nitrate reduction on the 100D Area reductive capacity requires consideration of mass balance and reaction rate effects. While dissolved oxygen and chromate reduction rates are rapid and essentially at equilibrium in the aquifer, nitrate transformation reactions are slow (100s of hours). In the limited (20-40 day) residence time in the ISRM barrier, only a portion of the nitrate will be reduced, whereas dissolved oxygen and chromate are reduced to completion. Assuming a groundwater flow rate of 1 ft/day, it is estimated that the ISRM barrier reductive capacity is 160 pore volumes (with no nitrate), and 85 pore volumes if 60 mg/L nitrate is present (i.e., a 47% decrease in the ISRM barrier longevity). Zones with more rapid groundwater flow will be less influenced by nitrate reduction. For example, a zone with a groundwater flow rate of 3 ft/day and 60 mg/L nitrate will have a reductive capacity of 130 pore volumes. Finally, long-term column experiments demonstrated the longevity of the reduced sediment barrier to reduce/immobilize 2 mg/L chromate in the presence of 8.4 mg/L dissolved oxygen (saturation), and 60 mg/L nitrate (maximums observed in the field). Initially the chromate reduction half-life was <0.1 h, 2.4 h by 120 pore volumes, and 17 h by 250 pore volumes. These chromate reduction rates are sufficiently fast relative to the 20-40 day residence time in the field for all chromate to be reduced/immobilized until the sediment is completely oxidized.

Szecsody, Jim E.; Phillips, Jerry L.; Vermeul, Vince R.; Fruchter, Jonathan S.; Williams, Mark D.

2005-07-15

345

Comparative EPR studies on the nitrite reductases from Escherichia coli and Wolinella succinogenes.  

PubMed

Hexaheme nitrite reductases purified to homogeneity from Escherichia coli K-12 and Wolinella succinogenes were studied by low-temperature EPR spectroscopy. In their isolated states, the two enzymes revealed nearly identical EPR spectra when measured at 12 K. Both high-spin and low-spin ferric heme EPR resonances with g values of 9.7, 3.7, 2.9, 2.3 and 1.5 were observed. These signals disappeared upon reduction by dithionite. Reaction of reduced enzyme with nitrite resulted in the formation of ferrous heme-NO complexes with distinct EPR spectral characteristics. The heme-NO complexes formed with the two enzymes differed, however, in g values and line-shapes. When reacted with hydroxylamine, reduced enzymes also showed the formation of ferrous heme-NO complexes. These results suggested the involvement of an enzyme-bound NO intermediate during the six-electron reduction of nitrite to ammonia catalyzed by these two hexaheme nitrite reductases. Heme proteins that can either expose bound NO to reduction or release it are significant components of both assimilatory and dissimilatory metabolisms of nitrate. The different ferrous heme-NO complexes detected for the two enzymes indicated, nevertheless, their subtle variation in heme reactivity during the reduction reaction. PMID:3036590

Liu, M C; Liu, M Y; Payne, W J; Peck, H D; Le Gall, J; DerVartanian, D V

1987-06-29

346

BAM Media M101: Motility Nitrate Medium  

Center for Food Safety and Applied Nutrition (CFSAN)

... Food. ... Tryptose, 10 g. Heart infusion agar (Difco), 8 g. Potassium (or sodium) nitrate, 1 g. Glucose, 0.5 g. ... NOTE: Make sure nitrates are nitrite-free. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

347

Soil bacteria, nitrite and the skin  

Microsoft Academic Search

Little is known about the composition of the skin microbiome and its potential significance for health and disease in the\\u000a context of the ‘hygiene hypothesis’. We here propose that mammals evolved with a dermal microflora that contributed to the\\u000a regulation of body physiology by providing nitrite from commensal ammonia-oxidising bacteria in response to ammonia released\\u000a during sweating. We further hypothesise

David R. Whitlock; Martin Feelisch

348

Nitrate ammonification by Nautilia profundicola AmH: experimental evidence consistent with a free hydroxylamine intermediate.  

PubMed

The process of nitrate reduction via nitrite controls the fate and bioavailability of mineral nitrogen within ecosystems; i.e., whether it is retained as ammonium (ammonification) or lost as nitrous oxide or dinitrogen (denitrification). Here, we present experimental evidence for a novel pathway of microbial nitrate reduction, the reverse hydroxylamine:ubiquinone reductase module (reverse-HURM) pathway. Instead of a classical ammonia-forming nitrite reductase that performs a 6 electron-transfer process, the pathway is thought to employ two catalytic redox modules operating in sequence: the reverse-HURM reducing nitrite to hydroxylamine followed by a hydroxylamine reductase that converts hydroxylamine to ammonium. Experiments were performed on Nautilia profundicola strain AmH, whose genome sequence led to the reverse-HURM pathway proposal. N. profundicola produced ammonium from nitrate, which was assimilated into biomass. Furthermore, genes encoding the catalysts of the reverse-HURM pathway were preferentially expressed during growth of N. profundicola on nitrate as an electron acceptor relative to cultures grown on polysulfide as an electron acceptor. Finally, nitrate-grown cells of N. profundicola were able to rapidly and stoichiometrically convert high concentrations of hydroxylamine to ammonium in resting cell assays. These experiments are consistent with the reverse-HURM pathway and a free hydroxylamine intermediate, but could not definitively exclude direct nitrite reduction to ammonium by the reverse-HURM with hydroxylamine as an off-pathway product. N. profundicola and related organisms are models for a new pathway of nitrate ammonification that may have global impact due to the wide distribution of these organisms in hypoxic environments and symbiotic or pathogenic associations with animal hosts. PMID:23847604

Hanson, Thomas E; Campbell, Barbara J; Kalis, Katie M; Campbell, Mark A; Klotz, Martin G

2013-07-04

349

Nitrite Uptake into Intact Pea Chloroplasts 1  

PubMed Central

The relationship between net nitrite uptake and its reduction in intact pea chloroplasts was investigated employing electron transport regulators, uncouplers, and photophosphorylation inhibitors. Observations confirmed the dependence of nitrite uptake on stromal pH and nitrite reduction but also suggested a partial dependance upon PSI phosphorylation. It was also suggested that ammonia stimulates nitrogen assimilation in the dark by association with stromal protons. Inhibition of nitrite uptake by N-ethylmaleimide and dinitrofluorobenzene could not be completely attributed to their inhibition of carbon dioxide fixation. Other protein binding reagents which inhibited photosynthesis showed no effect on nitrite uptake, except for p-chlormercuribenzoate which stimulated nitrite uptake. The results with N-ethylmaleimide and dinitrofluorobenzene tended to support the proposed presence of a protein permeation channel for nitrite uptake in addition to HNO2 penetration. On the basis of a lack of effect by known anion uptake inhibitors, it was concluded that the nitrite uptake mechanism was distinct from that of phosphate and chloride/sulfate transport.

Brunswick, Pamela; Cresswell, Christopher F.

1988-01-01

350

Improvement of autohydrogenotrophic nitrite reduction rate through optimization of pH and sodium bicarbonate dose in batch experiments  

Microsoft Academic Search

Accumulation of nitrite intermediate in autohydrogenotrophic denitrification process has been a challenging difficulty to tackle. This study showed that further growth of “true denitrifying” bacteria and adaptation to nitrite led to a faster reduction of nitrite than nitrate as a solution to circumvent nitrite accumulation. Moreover, two effective parameters namely pH and bicarbonate dose were optimized in order to achieve

Shahin Ghafari; Masitah Hasan; Mohamed Kheireddine Aroua

2009-01-01

351

Adding nitrate and phosphate separately or together in the Central Indian Ocean: a nutrient enrichment experiment  

NASA Astrophysics Data System (ADS)

Nutrient enrichment experiments were carried out in the Central Indian Ocean during the Chinese First Around-the world Research Cruise, adding nitrate, phosphate, or a mixture of both of them to surface seawater. The concentration of nitrate, nitrite, ammonia, and phosphate were analyzed spectrophotometrically, the chlorophyll-a concentration with fluorescence analysis, and the temperature variation during the experiment recorded. Addition of nitrate resulted in rapid growth of phytoplankton concomitant with depletion of nitrate in the water samples. No apparent variation occurred in chlorophyll-a concentration when phosphate was added. Combining nitrate and phosphate proved to be best to promote phytoplankton bloom, and nitrate was depleted prior to phosphate. After nitrate was consumed, a substantial amount of phytoplankton survived on the supplied phosphate. No correlation was found between the nitrate to phosphate ratio and chlorophyll-a or phytoplankton growth rate. We also found no correlation between water temperature and chlorophyll-a or phytoplankton growth rate. We conclude that neither nitrate to phosphate ratio nor water temperature control the growth of phytoplankton.

Tang, S.; Jiang, L.; Wu, Z. J.

2009-11-01

352

Thermochemical nitrate destruction  

SciTech Connect

The thermochemical destruction of nitrate was conducted in an aqueous media. Six reducing agents (ammonia, formate, urea, glucose, methane, and hydrogen) were mixed separately with 3 wt % NO[sub 3][sup [minus

Cox, J.L.; Hallen, R.T.; Lilga, M.A. (Pacific Northwest Lab., Richland, WA (United States))

1994-03-01

353

Nitrite formulations and their use as nitric oxide prodrugs  

US Patent & Trademark Office Database

Compositions comprising from about 40 weight parts to about 1000 weight parts of a botanical nitrate source; from about 20 weight parts to about 500 weight parts of a botanical source of nitrite reduction activity; and from about 4 weight parts to about 100 weight parts of a nitrite salt. Methods of reducing triglycerides or reducing C-reactive protein levels are also provided.

Bryan; Nathan Scott (Houston, TX); Zand; Janet (Spicewood, TX)

2012-11-06

354

Diversity, Physiology, and Niche Differentiation of Ammonia-Oxidizing Archaea  

PubMed Central

Nitrification, the aerobic oxidation of ammonia to nitrate via nitrite, has been suggested to have been a central part of the global biogeochemical nitrogen cycle since the oxygenation of Earth. The cultivation of several ammonia-oxidizing archaea (AOA) as well as the discovery that archaeal ammonia monooxygenase (amo)-like gene sequences are nearly ubiquitously distributed in the environment and outnumber their bacterial counterparts in many habitats fundamentally revised our understanding of nitrification. Surprising insights into the physiological distinctiveness of AOA are mirrored by the recognition of the phylogenetic uniqueness of these microbes, which fall within a novel archaeal phylum now known as Thaumarchaeota. The relative importance of AOA in nitrification, compared to ammonia-oxidizing bacteria (AOB), is still under debate. This minireview provides a synopsis of our current knowledge of the diversity and physiology of AOA, the factors controlling their ecology, and their role in carbon cycling as well as their potential involvement in the production of the greenhouse gas nitrous oxide. It emphasizes the importance of activity-based analyses in AOA studies and formulates priorities for future research.

2012-01-01

355

Diversity, physiology, and niche differentiation of ammonia-oxidizing archaea.  

PubMed

Nitrification, the aerobic oxidation of ammonia to nitrate via nitrite, has been suggested to have been a central part of the global biogeochemical nitrogen cycle since the oxygenation of Earth. The cultivation of several ammonia-oxidizing archaea (AOA) as well as the discovery that archaeal ammonia monooxygenase (amo)-like gene sequences are nearly ubiquitously distributed in the environment and outnumber their bacterial counterparts in many habitats fundamentally revised our understanding of nitrification. Surprising insights into the physiological distinctiveness of AOA are mirrored by the recognition of the phylogenetic uniqueness of these microbes, which fall within a novel archaeal phylum now known as Thaumarchaeota. The relative importance of AOA in nitrification, compared to ammonia-oxidizing bacteria (AOB), is still under debate. This minireview provides a synopsis of our current knowledge of the diversity and physiology of AOA, the factors controlling their ecology, and their role in carbon cycling as well as their potential involvement in the production of the greenhouse gas nitrous oxide. It emphasizes the importance of activity-based analyses in AOA studies and formulates priorities for future research. PMID:22923400

Hatzenpichler, Roland

2012-08-24

356

Nitrites derived from Foneiculum vulgare (fennel) seeds promotes vascular functions.  

PubMed

Recent evidence has demonstrated that nitrites play an important role in the cardiovascular system. Fennel (Foneiculum vulgare) seeds are often used as mouth fresheners after a meal in both the Indian sub-continent and around the world. The present study aims to quantify the nitrite and nitrates in fennel seeds as well as elucidating the effect of fennel derived-nitrites on vascular functions. Results from our study show that fennel seeds contain significantly higher amount of nitrites when compared to other commonly used post-meal seeds. Furthermore our study confirmed the functional effects of fennel derived-nitrites using in vitro and ex vivo models that describe the promotion of angiogenesis, cell migration, and vasorelaxation. We also showed that chewing fennel seeds enhanced nitrite content of saliva. Thus our study indicates the potential role of fennel derived-nitrites on the vascular system. PMID:23240972

Swaminathan, Akila; Sridhara, Sree Rama Chaitanya; Sinha, Swaraj; Nagarajan, Shunmugam; Balaguru, Uma Maheswari; Siamwala, Jamila H; Rajendran, Saranya; Saran, Uttara; Chatterjee, Suvro

2012-12-01

357

Abiotic Immobilization of Nitrate in Forest Soils: a Double Label Approach  

NASA Astrophysics Data System (ADS)

Mechanisms of soil nitrogen (N) retention remain a key uncertainty in the terrestrial N cycle. During recent work at the Harvard Forest Chronic N Experiment, 15N added to soils as ammonia nitrate was observed to be rapidly immobilized after addition to soil on a time scale of minutes. In published results it was hypothesized that the rapid time of immobilization could be explained by abiotic immobilization of both ammonia and nitrate. The possibility of abiotic immobilization of nitrate has been studied since the first half of the 20th century, mainly using ideal compounds and soil sterilization techniques. However, critics of these studies have argued that while in vitro studies may indicate the possibility of an abiotic reaction, they cannot demonstrate its plausibility in soils. Soil sterilization methods have been criticized, because they are not effective enough to eliminate biotic interactions within an experimental treatment. Isotopic tracer studies have also been used but also have problems differentiating biotic and abiotic reactions. This study is an attempt to demonstrate abiotic immobilization of nitrate in soil samples through the use of double labeled nitrate (15N18O3- ). The resolution of this method depends on the biochemistry of microbial immobilization of nitrate; reduction of nitrate to nitrite, then ammonia and glutamine before incorporation into microbial biomass. Reduction of 15N18O3- before microbial utilization of the 15N implies that retention of both heavy isotopes in the soil can only occur through abiotic reaction of 15N18Ox species. In biotic immobilization the 18O is lost to the system in water. While nitrate has proven unreactive in soils, its reduced product, nitrite, is known to be readily reactive with various soil compounds. Nitrite can be introduced into the soil environment naturally by both 'leakiness' in nitrification and denitrification and may possibly be generated abiotically through methods such as the proposed Ferrous Wheel hypothesis. Samples of the O-horizon of Harvard Forest red pine soils were incubated at several short intervals (15 m, 1 h, 4 h), based on previous observations made at Harvard Forest, under both anoxic and oxygenated conditions. Following incubation, KCl extraction of available N, and freeze drying, isotopic enrichment was determined by EA/TCEA Mass Spectroscopy. Preliminary results showed a significant enrichment in 15N and a small but significant enrichment in 18O. The full results of the experiment will be available by the Fall meeting.

Maclean, R. W.; Ollinger, S. V.; Hobbie, E. A.; Frey, S. D.; Dail, D. B.

2007-12-01

358

Cytochrome c nitrite reductase from Wolinella succinogenes. Structure at 1.6 A resolution, inhibitor binding, and heme-packing motifs.  

PubMed

Cytochrome c nitrite reductase catalyzes the 6-electron reduction of nitrite to ammonia. This second part of the respiratory pathway of nitrate ammonification is a key step in the biological nitrogen cycle. The x-ray structure of the enzyme from the epsilon-proteobacterium Wolinella succinogenes has been solved to a resolution of 1.6 A. It is a pentaheme c-type cytochrome whose heme groups are packed in characteristic motifs that also occur in other multiheme cytochromes. Structures of W. succinogenes nitrite reductase have been obtained with water bound to the active site heme iron as well as complexes with two inhibitors, sulfate and azide, whose binding modes and inhibitory functions differ significantly. Cytochrome c nitrite reductase is part of a highly optimized respiratory system found in a wide range of Gram-negative bacteria. It reduces both anionic and neutral substrates at the distal side of a lysine-coordinated high-spin heme group, which is accessible through two different channels, allowing for a guided flow of reaction educt and product. Based on sequence comparison and secondary structure prediction, we have demonstrated that cytochrome c nitrite reductases constitute a protein family of high structural similarity. PMID:10984487

Einsle, O; Stach, P; Messerschmidt, A; Simon, J; Kröger, A; Huber, R; Kroneck, P M

2000-12-15

359

Nitrite transport to the chloroplast in Chlamydomonas reinhardtii: molecular evidence for a regulated process  

Microsoft Academic Search

Nitrite transport to the chloroplast is not a well documented process in spite of being a central step in the nitrate assimilation pathway. The lack of molecular evidence, as well as the easy diffusion of nitrite through biological membranes, have made this physiological process difficult to understand in plant nutrition. The aim of this review is to illustrate that nitrite

Aurora Galvan; Jesus Rexach; Vicente Mariscal; Emilio Fernandez

2010-01-01

360

Chemical removal of nitrate from water  

Microsoft Academic Search

HIGH levels of nitrate in ground water can pose a serious health risk. Reduction of nitrate to nitrite in the gut may cause methemoglobinaemia1both in newborn infants and in adults deficient in glucose-phosphate dehydrogenase2. Under abnormal circumstances, reduction to nitrite can also occur in the stomach to form N-nitrosamines, a postulated cause of stomach cancer3. Nitrate outflow onto shallow continental

Andrew P. Murphy

1991-01-01

361

Nitrous Oxide Formation in the Colne Estuary, England: the Central Role of Nitrite  

PubMed Central

Nitrate and nitrite concentrations in the water and nitrous oxide and nitrite fluxes across the sediment-water interface were measured monthly in the River Colne estuary, England, from December 1996 to March 1998. Water column concentrations of N2O in the Colne were supersaturated with respect to air, indicating that the estuary was a source of N2O for the atmosphere. At the freshwater end of the estuary, nitrous oxide effluxes from the sediment were closely correlated with the nitrite concentrations in the overlying water and with the nitrite influx into the sediment. Increases in N2O production from sediments were about 10 times greater with the addition of nitrite than with the addition of nitrate. Rates of denitrification were stimulated to a larger extent by enhanced nitrite than by nitrate concentrations. At 550 ?M nitrite or nitrate (the highest concentration used), the rates of denitrification were 600 ?mol N · m?2 · h?1 with nitrite but only 180 ?mol N · m?2 · h?1 with nitrate. The ratios of rates of nitrous oxide production and denitrification (N2O/N2 × 100) were significantly higher with the addition of nitrite (7 to 13% of denitrification) than with nitrate (2 to 4% of denitrification). The results suggested that in addition to anaerobic bacteria, which possess the complete denitrification pathway for N2 formation in the estuarine sediments, there may be two other groups of bacteria: nitrite denitrifiers, which reduce nitrite to N2 via N2O, and obligate nitrite-denitrifying bacteria, which reduce nitrite to N2O as the end product. Consideration of free-energy changes during N2O formation led to the conclusion that N2O formation using nitrite as the electron acceptor is favored in the Colne estuary and may be a critical factor regulating the formation of N2O in high-nutrient-load estuaries.

Dong, Liang F.; Nedwell, David B.; Underwood, Graham J. C.; Thornton, Daniel C. O.; Rusmana, Iman

2002-01-01

362

Correlation between total nitrite/nitrate concentrations and monoamine oxidase (types A and B) and semicarbazide-sensitive amine oxidase enzymatic activities in human mesenteric arteries from non-diabetic and type 2 diabetic patients.  

PubMed

The aim of this study was to determine the correlation between total nitrite/nitrate concentrations (NOx) and the kinetic parameters of monoamine oxidase enzymes (MAO-A and MAO-B) and semicarbazide-sensitive amine oxidase (SSAO) in human mesenteric arteries. Arteries were from non-diabetic and type 2 diabetic patients with sigmoid or rectum carcinoma for whom surgery was the first option and who were not exposed to neo-adjuvant therapy. Segments of human inferior mesenteric arteries from non-diabetic (61.1 ± 8.9 years old, 7 males and 5 females, N = 12) and type 2 diabetic patients (65.8 ± 6.2 years old, 8 males and 4 females, N = 12) were used to determine NOx concentrations and the kinetic parameters of MAO-A, MAO-B and SSAO by the Griess reaction and by radiochemical assay, respectively. The NOx concentrations in arteries from diabetic patients did not differ significantly from those of the non-diabetic group (10.28 ± 4.61 vs 10.71 ± 4.32 nmol/mg protein, respectively). In the non-diabetic group, there was a positive correlation between NOx concentrations and MAO-B parameters: Km (r = 0.612, P = 0.034) and Vmax (r = 0.593, P = 0.042), and a negative correlation with the SSAO parameters: Km (r = -0.625, P = 0.029) and Vmax (r = -0.754, P = 0.005). However, in the diabetic group no correlation was found between NOx concentrations and the three kinetic parameters of the enzymes. These results suggest an important function of sympathetic nerves and vascular NOx concentrations in arteries of non-diabetic patients. Thus, these results confirm the importance of a balance between oxidants and antioxidants in the maintenance of vascular homeostasis to prevent oxidative stress. PMID:22124705

Nunes, S F; Figueiredo, I V; Pereira, J S; Lopes, M C; Caramona, M M

2011-11-25

363

Crp-dependent cytochrome bd oxidase confers nitrite resistance to Shewanella oneidensis.  

PubMed

Shewanella oneidensis is able to respire on a variety of organic and inorganic substrates, including nitrate and nitrite. Conversion of nitrate to nitrite and nitrite to ammonium is catalysed by periplasmic nitrate and nitrite reductases (NAP and NRF) respectively. Global regulator Crp (cyclic AMP receptor protein) is essential for growth of S.?oneidensis on both nitrate and nitrite. In this study, we discovered that crp mutants are not only severely deficient in nitrate or nitrite respiration, but are also hypersensitive to nitrite. This hypersusceptibility phenotype is independent of nitrite respiration. Using random transposon mutagenesis, we obtained 73 ?crp suppressor strains resistant to nitrite. Transposon insertion sites in 24 suppressor strains were exclusively mapped in the region upstream of the cyd operon encoding a cytochrome bd oxidase, resulting in expression of the operon now driven by a Crp-independent promoter. Further investigation indicated that the promoter in suppressor strains comes from the transposon. Mutational analysis of the cydB gene (encoding the essential subunit II of the bd oxidase) confirmed that the cytochrome bd oxidase confers nitrite resistance to S.?oneidensis. PMID:23414111

Fu, Huihui; Chen, Haijiang; Wang, Jixuan; Zhou, Guangqi; Zhang, Haiyan; Zhang, Lili; Gao, Haichun

2013-02-17

364

Diversity of the bacterial community in a bioreactor during ammonia gas removal.  

PubMed

Polymerase chain reaction analysis in combination with denaturing gradient gel electrophoresis (DGGE) was used to determine changes in the composition of the bacterial community of a bioreactor during ammonia removal. A minimum of 13 bands were observed in the DGGE profile. Phylogenetic analysis revealed that phylum Proteobacteria was predominantly represented in the bacterial community of the bioreactor, followed by Firmicutes, Actinobacteria, and Flavobacteriaceae. However, the occurrence and predominance of specific bacterial species varied with the concentrations of NH(3) introduced into the bioreactor. The complexity of the bacterial species generally decreased with increasing inlet NH(3) concentration. Based on the characteristics of the identified species, there is a potential for nitrification, denitrification, nitrate reduction, nitrite reduction, and ammonia assimilation to occur simultaneously in the bioreactor. The strains identified in this study are potential candidate strains for the purification of waste gases containing high concentrations of NH(3). PMID:19716695

Cheng, Chiu-Yu; Mei, Hui-Ching; Tsao, Chia-Fen; Liao, Yi-Ru; Huang, Hsiao-Han; Chung, Ying-Chien

2009-08-28

365

[Achieve single-stage autotrophic biological nitrogen removal process by controlling the concentration of free ammonia].  

PubMed

Through controlling the concentration of free ammonia in the sequencing batch reactor (SBR), the single-stage autotrophic biological nitrogen removal process was achieved, including partial nitrification and anaerobic ammonium oxidation. The experiment was completed via two steps, the enrichment of nitrite bacteria and the inoculation of the mixture of anammox biomass. The operating temperature in the SBR was (31 +/- 2) degrees C. During the step of the enrichment of nitrite bacteria, pH was about 7.8. Changes of FA concentration were achieved by controlling the concentration of influent NH4(+) -N(56-446 mg x L(-1)), in order to inhibit and eliminate the nitrate bacteria. The activity tests of the sludge, 55d after enrichment, showed strong activity of aerobic ammonium oxidation [2.91 kg x (kg x d)(-1)] and low activity of nitrite oxidation [0.03 kg x(kg x d)(-1)]. During the inoculation of the mixture of anammox biomass, changes of FA concentration were achieved by controlling the concentration of influent NH4(+) -N and pH. As the inoculation of anammox biomass, abundant of bacteria and nutrient content were into the reactor and there kept high activity of aerobic ammonium oxidation [2.83 kg x (kg x d)(-1)] and a certain activity of nitrite oxidation, at the same time, the activity of anammox and heterotrophic denitrification reached 0.65 kg x (kg x d)(-1) and 0.11 kg x (kg x d)(-1), respectively. PMID:21404687

Ji, Li-Li; Yang, Zhao-Hui; Xu, Zheng-Yong; Li, Xiao-Jiang; Tang, Zhi-Gang; Deng, Jiu-Hu

2011-01-01

366

Protection against oral and gastrointestinal diseases: Importance of dietary nitrate intake, oral nitrate reduction and enterosalivary nitrate circulation  

Microsoft Academic Search

Over the last 20 years, dietary nitrate has been implicated in the formation of methemoglobin and carcinogenic nitrosamines in humans. This has led to restrictions of nitrate and nitrite levels in food and drinking water. However, there is no epidemiological evidence for an increased risk of gastric and intestinal cancer in population groups with high dietary vegetable or nitrate intake.

Callum Duncan; Hong Li; Roelf Dykhuizen; Rennie Frazer; Peter Johnston; Gillian MacKnight; Lorna Smith; Kathryn Lamza; Hamish McKenzie; Les Batt; Denise Kelly; Michael Golden; Nigel Benjamin; Carlo Leifert

1997-01-01

367

Nitrate Reductase from Squash: cDNA Cloning and Nitrate Regulation  

Microsoft Academic Search

The assimilation of nitrate in plants involves the reduction of nitrate to ammonia in two steps. The first step requires nitrate reductase, a nitrate-inducible enzyme. When seedlings of squash (Cucurbita maxima L.) were treated with nitrate, both nitrate reductase activity and protein were induced in the cotyledons. Poly(A)+ RNA was prepared from cotyledons of nitrate-treated seedlings and was used to

Nigel M. Crawford; Wilbur H. Campbell; Ronald W. Davis

1986-01-01

368

Photosynthetic nitrate assimilation in cyanobacteria.  

PubMed

Nitrate uptake and reduction to nitrite and ammonium are driven in cyanobacteria by photosynthetically generated assimilatory power, i.e., ATP and reduced ferredoxin. High-affinity nitrate and nitrite uptake takes place in different cyanobacteria through either an ABC-type transporter or a permease from the major facilitator superfamily (MFS). Nitrate reductase and nitrite reductase are ferredoxin-dependent metalloenzymes that carry as prosthetic groups a [4Fe-4S] center and Mo-bis-molybdopterin guanine dinucleotide (nitrate reductase) and [4Fe-4S] and siroheme centers (nitrite reductase). Nitrate assimilation genes are commonly found forming an operon with the structure: nir (nitrite reductase)-permease gene(s)-narB (nitrate reductase). When the cells perceive a high C to N ratio, this operon is transcribed from a complex promoter that includes binding sites for NtcA, a global nitrogen-control regulator that belongs to the CAP family of bacterial transcription factors, and NtcB, a pathway-specific regulator that belongs to the LysR family of bacterial transcription factors. Transcription is also affected by other factors such as CnaT, a putative glycosyl transferase, and the signal transduction protein P(II). The latter is also a key factor for regulation of the activity of the ABC-type nitrate/nitrite transporter, which is inhibited when the cells are incubated in the presence of ammonium or in the absence of CO(2). Notwithstanding significant advance in understanding the regulation of nitrate assimilation in cyanobacteria, further post-transcriptional regulatory mechanisms are likely to be discovered. PMID:16143847

Flores, Enrique; Frías, José E; Rubio, Luis M; Herrero, Antonia

2005-01-01

369

AMMONIA: ENVIRONMENTAL IMPACTS, EMISSIONS, INORGANIC PM 2.5, AND CLEAN AIR INTERSTATE RULE  

EPA Science Inventory

This presentation discusses the role of ammonia as an atmospheric pollutant. Ammonia is emitted primarily from agricultural sources, although vehicles are the largest sources in urban centers. When combined with nitrate and sulfate, ammonia forms particulate matter which has be...

370

Cloning and Nitrate Induction of Nitrate Reductase mRNA  

Microsoft Academic Search

Nitrate is the major source of nitrogen taken from the soil by higher plants but requires reduction to ammonia prior to incorporation into amino acids. The first enzyme in the reducing pathway is a nitrate-inducible enzyme, nitrate reductase (EC 1.6.6.1). A specific polyclonal antiserum raised against purified barley nitrate reductase has been used to immunoprecipitate in vivo labeled protein and

Chi-Lien Cheng; Julia Dewdney; Andris Kleinhofs; Howard M. Goodman

1986-01-01

371

Dietary Nitrite Restores NO Homeostasis and is Cardioprotective in eNOS Deficient Mice  

PubMed Central

Endothelial production of nitric oxide (NO) is critical for vascular homeostasis. Nitrite and nitrate are formed endogenously by the step wise oxidation of NO and have for years been regarded as inactive degradation products. As a result both anions are routinely used as surrogate markers of NO production with nitrite as a more sensitive marker. However, both nitrite and nitrate are derived from dietary sources. We sought to determine how exogenous nitrite affects steady state concentrations of NO metabolites thought to originate from NOS derived NO as well as blood pressure and myocardial ischemia-reperfusion (I/R) injury. Mice deficient in endothelial nitric oxide synthase (eNOS?/?) demonstrated decreased blood and tissue nitrite, nitrate and nitroso which were further reduced by low nitrite (NOx) diet for 1 week. Nitrite supplementation (50mg/L) in the drinking water for 1 week restored NO homeostasis in eNOS?/? mice and protected against I/R injury. Nitrite failed to alter heart rate or mean arterial blood pressure at the protective dose. These data demonstrate the significant influence of dietary nitrite intake on the maintenance of steady-state NO levels. Dietary nitrite and nitrate may serve as essentials nutrient for optimal cardiovascular health and may provide a novel prevention/treatment modality for disease associated with NO insufficiency.

Bryan, Nathan S.; Calvert, John W.; Gundewar, Susheel; Lefer, David J.

2008-01-01

372

Oil field souring control by nitrate-reducing Sulfurospirillum spp. that outcompete sulfate-reducing bacteria for organic electron donors.  

PubMed

Nitrate injection into oil reservoirs can prevent and remediate souring, the production of hydrogen sulfide by sulfate-reducing bacteria (SRB). Nitrate stimulates nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB) and heterotrophic nitrate-reducing bacteria (hNRB) that compete with SRB for degradable oil organics. Up-flow, packed-bed bioreactors inoculated with water produced from an oil field and injected with lactate, sulfate, and nitrate served as sources for isolating several NRB, including Sulfurospirillum and Thauera spp. The former coupled reduction of nitrate to nitrite and ammonia with oxidation of either lactate (hNRB activity) or sulfide (NR-SOB activity). Souring control in a bioreactor receiving 12.5 mM lactate and 6, 2, 0.75, or 0.013 mM sulfate always required injection of 10 mM nitrate, irrespective of the sulfate concentration. Community analysis revealed that at all but the lowest sulfate concentration (0.013 mM), significant SRB were present. At 0.013 mM sulfate, direct hNRB-mediated oxidation of lactate by nitrate appeared to be the dominant mechanism. The absence of significant SRB indicated that sulfur cycling does not occur at such low sulfate concentrations. The metabolically versatile Sulfurospirillum spp. were dominant when nitrate was present in the bioreactor. Analysis of cocultures of Desulfovibrio sp. strain Lac3, Lac6, or Lac15 and Sulfurospirillum sp. strain KW indicated its hNRB activity and ability to produce inhibitory concentrations of nitrite to be key factors for it to successfully outcompete oil field SRB. PMID:17308184

Hubert, Casey; Voordouw, Gerrit

2007-02-16

373

Inorganic nitrite therapy: historical perspective and future directions.  

PubMed

Over the past several years, investigators studying nitric oxide (NO) biology and metabolism have come to learn that the one-electron oxidation product of NO, nitrite anion, serves as a unique player in modulating tissue NO bioavailability. Numerous studies have examined how this oxidized metabolite of NO can act as a salvage pathway for maintaining NO equivalents through multiple reduction mechanisms in permissive tissue environments. Moreover, it is now clear that nitrite anion production and distribution throughout the body can act in an endocrine manner to augment NO bioavailability, which is important for physiological and pathological processes. These discoveries have led to renewed hope and efforts for an effective NO-based therapeutic agent through the unique action of sodium nitrite as an NO prodrug. More recent studies also indicate that sodium nitrate may also increase plasma nitrite levels via the enterosalivary circulatory system resulting in nitrate reduction to nitrite by microorganisms found within the oral cavity. In this review, we discuss the importance of nitrite anion in several disease models along with an appraisal of sodium nitrite therapy in the clinic, potential caveats of such clinical uses, and future possibilities for nitrite-based therapies. PMID:21619929

Kevil, Christopher G; Kolluru, Gopi K; Pattillo, Christopher B; Giordano, Tony

2011-05-04

374

Molecular Structure of Ammonia  

NSDL National Science Digital Library

Ammonia is a non-ionic colorless gas at ambient temperatures and a hydrogen bonding liquid at 240 Kelvin that has the remarkable ability to dissolve alkali metals. Ammonia is a Lewis base and is readily absorbed by water to form small amounts of ammonium hydroxide (pKb = 4.74). Naturally, ammonia has its sources in the biosphere (the nitrogen cycle) and is a trace gas in air and a source of ammonium ions in rain and atmospheric aerosols. Ammonia is prepared industrially by the Haber-Bosch process in quantities exceeding 120 million metric tons per year. In this process, ammonia gas is formed when hydrogen and nitrogen (3:1) are compressed to pressures of 200 atm and passed over an iron catalyst at 380-450 degrees C. Much of the ammonia produced this way (85%) is used as fertilizers on crops, a significant portion of which leaches from croplands into streams causing nitrate pollution and eutrophication of waterways (e.g., dead-zone in the Gulf of Mexico). Other sources of ammonia include combustion (coal and biomass burning) and from bacterial decomposition of animal excreta.

2006-05-02

375

Rapid abiotic transformation of nitrate in an acid forest soil  

Microsoft Academic Search

Nitrate immobilization into organic matter is thought to require catalysis by the enzymes of soil microorganisms. However, recent studies suggest that nitrate added to soil is immobilized rapidly and this process may include abiotic pathways. We amended living and sterilized soil with 15N-labeled nitrate and nitrite to investigate biotic and abiotic immobiliz- ation. We report rapid transformation of nitrate in

DAVID BRYAN DAIL; RIC A. DAVIDSON; JON CHOROVER

2001-01-01

376

Structure of octaheme cytochrome c nitrite reductase from Thioalkalivibrio nitratireducens in a complex with phosphate  

Microsoft Academic Search

Octaheme cytochrome c nitrite reductase from Thioalkalivibrio nitratireducens (TvNiR) catalyzes the reduction of nitrite and hydroxylamine to ammonia. The structures of the free enzyme and of the enzyme\\u000a in complexes with the substrate (nitrite ion) and the inhibitor (azide ion) have been solved previously. In this study we\\u000a report the structures of the oxidized complex of TvNiR with phosphate and

A. A. Trofimov; K. M. Polyakov; K. M. Bo?ko; A. A. Filimonenkov; P. V. Dorovatovskii; T. V. Tikhonova; V. O. Popov; M. V. Koval’chuk

2010-01-01

377

Achieving nitritation and anammox enrichment in a single moving-bed biofilm reactor treating reject water  

Microsoft Academic Search

A biofilm with high nitrifying efficiency was converted into a nitritating and thereafter a nitritating–anammox biofilm in a moving-bed biofilm reactor at 26.5 (±0.5)°C by means of a combination of intermittent aeration, low dissolved oxygen concentration, low hydraulic retention time, free ammonia and furthermore, also by elevated HCO concentration. Nitrite-oxidizing bacteria (NOB) were more effectively suppressed by an enhanced HCO

I. Zekker; E. Rikmann; T. Tenno; A. Saluste; M. Tomingas; A. Menert; L. Loorits; Vallo Lemmiksoo

2012-01-01

378

Rapid colorimetric determination of nitrate in plant tissue by nitration of salicylic acid  

Microsoft Academic Search

An analysis is described for the rapid determination of nitrate?N in plant extracts. The complex formed by nitration of salicylic acid under highly acidic conditions absorbs maximally at 410 nm in basic (pH>12) solutions. Absorbance of the chromophore is directly proportional to the amount of nitrate?N present. Ammonium, nitrite, and chloride ions do not interfere.

D. A. Cataldo; M. Maroon; L. E. Schrader; V. L. Youngs

1975-01-01

379

An Ecologic Study of Nitrate in Municipal Drinking Water and Cancer Incidence in Trnava District, Slovakia  

Microsoft Academic Search

Contamination of drinking water by nitrate is an evolving public health concern since nitrate can undergo endogenous reduction to nitrite, and nitrosation of nitrites can form N-nitroso compounds, which are potent carcinogens. We conducted an ecologic study to determine whether nitrate levels in drinking water were correlated with non-Hodgkin lymphoma and cancers of the digestive and urinary tracts in an

Gabriel Gulis; Monika Czompolyova; James R. Cerhan

2002-01-01

380

Nitrate reduction in a simulated free-water surface wetland system.  

PubMed

The feasibility of using a constructed wetland for treatment of nitrate-contaminated groundwater resulting from the land application of biosolids was investigated for a site in the southeastern United States. Biosolids degradation led to the release of ammonia, which upon oxidation resulted in nitrate concentrations in the upper aquifer in the range of 65-400 mg N/L. A laboratory-scale system was constructed in support of a pilot-scale project to investigate the effect of temperature, hydraulic retention time (HRT) and nitrate and carbon loading on denitrification using soil and groundwater from the biosolids application site. The maximum specific reduction rates (MSRR), measured in batch assays conducted with an open to the atmosphere reactor at four initial nitrate concentrations from 70 to 400 mg N/L, showed that the nitrate reduction rate was not affected by the initial nitrate concentration. The MSRR values at 22 °C for nitrate and nitrite were 1.2 ± 0.2 and 0.7 ± 0.1 mg N/mg VSS(COD)-day, respectively. MSRR values were also measured at 5, 10, 15 and 22 °C and the temperature coefficient for nitrate reduction was estimated at 1.13. Based on the performance of laboratory-scale continuous-flow reactors and model simulations, wetland performance can be maintained at high nitrogen removal efficiency (>90%) with an HRT of 3 days or higher and at temperature values as low as 5 °C, as long as there is sufficient biodegradable carbon available to achieve complete denitrification. The results of this study show that based on the climate in the southeastern United States, a constructed wetland can be used for the treatment of nitrate-contaminated groundwater to low, acceptable nitrate levels. PMID:21885082

Misiti, Teresa M; Hajaya, Malek G; Pavlostathis, Spyros G

2011-08-22

381

Swimming performance of channel catfish (Ictalurus punctatus) after nitrite exposure  

SciTech Connect

Tests of prolonged swimming are generally considered most useful in sublethal stress assessment, as they draw on both major biochemical energy sources. No research to date has quantified either the swimming performance of I. punctatus or effects of nitrite exposure on swimming of any species. Our purpose was to determine if nitrite exposure affects the prolonged swimming performance of channel catfish, and to delineate the extent that methemoglobinemia resulting from nitrate exposure correlates with performance.

Watenpaugh, D.E.; Beitinger, T.L.

1985-05-01

382

The photochemistry of aqueous nitrate ion revisited  

Microsoft Academic Search

Aqueous nitrate solutions were photolysed at 254 nm in the absence of oxidizable additives, in the presence of methanol or propan-2-ol and oxygen and in the presence of cyclopentane under anaerobic conditions. The main nitrogen-containing products are nitrite and peroxynitrite. The quantum yields depend on the pH, nitrate concentration, nature of the additive and the light intensity. The intrinsic nitrite

Gertraud Mark; Hans-Gert Korth; Heinz-Peter Schuchmann; Clemens von Sonntag

1996-01-01

383

Autotrophic ammonia-oxidizing bacteria contribute minimally to nitrification in a nitrogen-impacted forested ecosystem.  

PubMed

Deposition rates of atmospheric nitrogenous pollutants to forests in the San Bernardino Mountains range east of Los Angeles, California, are the highest reported in North America. Acidic soils from the west end of the range are N-saturated and have elevated rates of N-mineralization, nitrification, and nitrate leaching. We assessed the impact of this heavy nitrogen load on autotrophic ammonia-oxidizing communities by investigating their composition, abundance, and activity. Analysis of 177 cloned beta-Proteobacteria ammonia oxidizer 16S rRNA genes from highly to moderately N-impacted soils revealed similar levels of species composition; all of the soils supported the previously characterized Nitrosospira clusters 2, 3, and 4. Ammonia oxidizer abundance measured by quantitative PCR was also similar among the soils. However, rates of potential nitrification activity were greater for N-saturated soils than for soils collected from a less impacted site, but autotrophic (i.e., acetylene-sensitive) activity was low in all soils examined. N-saturated soils incubated for 30 days with ammonium accumulated additional soluble ammonium, whereas less-N-impacted soils had a net loss of ammonium. Lastly, nitrite production by cultivated Nitrosospira multiformis, an autotrophic ammonia-oxidizing bacterium adapted to relatively high ammonium concentrations, was significantly inhibited in pH-controlled slurries of sterilized soils amended with ammonium despite the maintenance of optimal ammonia-oxidizing conditions. Together, these results showed that factors other than autotrophic ammonia oxidizers contributed to high nitrification rates in these N-impacted forest soils and, unlike many other environments, differences in nitrogen content and soil pH did not favor particular autotrophic ammonia oxidizer groups. PMID:15640188

Jordan, Fiona L; Cantera, J Jason L; Fenn, Mark E; Stein, Lisa Y

2005-01-01

384

Autotrophic Ammonia-Oxidizing Bacteria Contribute Minimally to Nitrification in a Nitrogen-Impacted Forested Ecosystem  

PubMed Central

Deposition rates of atmospheric nitrogenous pollutants to forests in the San Bernardino Mountains range east of Los Angeles, California, are the highest reported in North America. Acidic soils from the west end of the range are N-saturated and have elevated rates of N-mineralization, nitrification, and nitrate leaching. We assessed the impact of this heavy nitrogen load on autotrophic ammonia-oxidizing communities by investigating their composition, abundance, and activity. Analysis of 177 cloned ?-Proteobacteria ammonia oxidizer 16S rRNA genes from highly to moderately N-impacted soils revealed similar levels of species composition; all of the soils supported the previously characterized Nitrosospira clusters 2, 3, and 4. Ammonia oxidizer abundance measured by quantitative PCR was also similar among the soils. However, rates of potential nitrification activity were greater for N-saturated soils than for soils collected from a less impacted site, but autotrophic (i.e., acetylene-sensitive) activity was low in all soils examined. N-saturated soils incubated for 30 days with ammonium accumulated additional soluble ammonium, whereas less-N-impacted soils had a net loss of ammonium. Lastly, nitrite production by cultivated Nitrosospira multiformis, an autotrophic ammonia-oxidizing bacterium adapted to relatively high ammonium concentrations, was significantly inhibited in pH-controlled slurries of sterilized soils amended with ammonium despite the maintenance of optimal ammonia-oxidizing conditions. Together, these results showed that factors other than autotrophic ammonia oxidizers contributed to high nitrification rates in these N-impacted forest soils and, unlike many other environments, differences in nitrogen content and soil pH did not favor particular autotrophic ammonia oxidizer groups.

Jordan, Fiona L.; Cantera, J. Jason L.; Fenn, Mark E.; Stein, Lisa Y.

2005-01-01

385

Kinetics of nitrite evaluated in a meat product.  

PubMed

The evaluation of the efficiency with which the reactions involving nitrite proceed in mortadella and of the effect exercised on their kinetics by some variables (ingoing amount of sodium nitrite and temperature) is the purpose of this work. Kinetics parameters were calculated at each level of nitrite added (40, 70, 100 and 150 mg/kg) and at five temperature (55°, 60°, 65°, 70° and 72 °C). While the colour formation reaction is favoured by low activation energy, it becomes crucial to enable nitrite to proceed according to direct reduction thus preventing an increase in nitrate concentration as well as an excess of nitric oxide in the product. Kinetics data suggest that this scope is performed when the product achieves the temperature of 65 °C as fast as possible with an ingoing amount of sodium nitrite of 70 mg/kg. PMID:23031270

Barbieri, G; Bergamaschi, M; Barbieri, Ge; Franceschini, M

2012-09-13

386

Spectrophotometric determination of nitrite using salbutamol sulfate as a reagent  

SciTech Connect

A simple spectrophotometric method for the trace determination of nitrite (NO/sub 2//sup /minus//) is described. Nitrite is reacted with Salbutamol sulfate in acidic medium which gives a yellow color in alkaline medium (less than or equal to pH 7) and can be determined in the presence of several cations and anions. Beer's law is obeyed in the range of 1.8 to 27.6 ppm of nitrite with the molar absorptivity 1.8 /times/ 10/sup 3/ 1 /times/ mole /sup /minus/1/ /times/ cm/sup /minus/1/ at 410 nm. The proposed method can also be utilized for the determination of nitrate (NO/sub 3//sup /minus//) after its reduction to nitrite. The method has been applied for the determination of various samples containing traces of nitrite.

Agrawal, Y.K.; Bhatt, P.N.

1988-01-01

387

Reduced nicotinamide-adenine dinucleotide-nitrite reductase from Azotobacter chroococcum  

PubMed Central

1. The assimilatory nitrite reductase of the N2-fixing bacterium Azotobacter chroococcum was prepared in a soluble form from cells grown aerobically with nitrate as the nitrogen source, and some of its properties have been studied. 2. The enzyme is a FAD-dependent metalloprotein (mol.wt. about 67000), which stoicheiometrically catalyses the direct reduction of nitrite to NH3 with NADH as the electron donor. 3. NADH–nitrite reductase can exist in two either active or inactive interconvertible forms. Inactivation in vitro can be achieved by preincubation with NADH. Nitrite can specifically protect the enzyme against this inactivation and reverse the process once it has occurred. 4. A. chroococcum nitrite reductase is an adaptive enzyme whose formation depends on the presence of either nitrate or nitrite in the nutrient solution. 5. Tungstate inhibits growth of the microorganism very efficiently, by competition with molybdate, when nitrate is the nitrogen source, but does not interfere when nitrite or NH3 is substituted for nitrate. The addition of tungstate to the culture media results in the loss of nitrate reductase activity but does not affect nitrite reductase.

Vega, J. M.; Guerrero, M. G.; Leadbetter, E.; Losada, M.

1973-01-01

388

Characteristics of Nitrate Reduction in a Mutant of the Blue-Green Alga Agmenellum quadruplicatum.  

PubMed

Characteristics of nitrate reduction in terms of nitrite production in an N-methyl-N'-nitro-N-nitrosoguanidine-induced mutant of the blue-green alga Agmenellum quadruplicatum are described. Following induction of nitrate reduction a linear rate of nitrite production proportional to cell concentration was observed. Rate of nitrite production and growth rate showed similar responses to pH, temperature, and light intensity. If required, only trace amounts of carbon dioxide were necessary for nitrite production. Atmospheres of oxygen or nitrogen inhibited production of nitrite. In addition, a low but constant rate of nitrite production was observed in the dark. Nitrite production by mutant AQ-6 was studied in terms of photosynthesis. As nitrite production proceeded, rate of photosynthesis declined. Ultraviolet irradiation and 3-(3,4-dichlorophenyl)-1, 1-dimethylurea poisoning did not prevent nitrite production. The action spectrum of nitrite production was chlorophyll a-like. PMID:16658328

Stevens, S E; Van Baalen, C

1973-02-01

389

Regulation of the hexaheme nitrite/nitric oxide reductase of Desulfovibrio desulfuricans, Wolinella succinogenes and Escherichia coli. A mass spectrometric study.  

PubMed

Dissimilatory nitrite reduction, carried out by hexaheme proteins, gives ammonia as the final product. Representatives of this enzyme group from 3 bacterial species can also reduce NO to either ammonia or N2O. The redox regulation of the nitrite/nitric oxide activities is discussed in the context of the denitrifying pathway. PMID:2265715

Costa, C; Macedo, A; Moura, I; Moura, J J; Le Gall, J; Berlier, Y; Liu, M Y; Payne, W J

1990-12-10

390

The nitrate to ammonia and ceramic (NAC) process for the denitration and immobilization of low-level radioactive liquid waste (LLW)  

Microsoft Academic Search

Hazardous radioactive liquid waste is the legacy of more than 50 years of plutonium production associated with the United States' nuclear weapons program. It is estimated that more than 245,000 tons of nitrate wastes are stored at facilities such as the single-shell tanks (SST) at the Hanford Site in the state of Washington, and the Melton Valley storage tanks at

Ivan Muguercia

1997-01-01

391

Viewpoint : Isotopic fractionation by plant nitrate reductase, twenty years later  

Microsoft Academic Search

Plant nitrate reductase, the enzyme that reduces nitrate (NO3?) to nitrite (NO2?), is known to fractionate N isotopes, depleting nitrite in 15N compared with substrate nitrate. Nearly 20 years ago, the nitrogen isotope effect associated with this reaction was found to be around 1.015. However, the relationships between the isotope effect and the mechanism of the reaction have not yet

Guillaume TcherkezA; Graham D. FarquharB

2006-01-01

392

Combination process of limited filamentous bulking and nitrogen removal via nitrite for enhancing nitrogen removal and reducing aeration requirements.  

PubMed

Limited filamentous bulking (LFB) activated sludge process was proposed by Guo et al. (2010) to increase the removal of tiny suspended particulates in the clarifier and reduce aeration energy consumption. However, when the use of LFB process, ammonium removal efficiency would be compromised due to low dissolved oxygen (DO). In this study, the combination process of nitrogen removal via nitrite and LFB was achieved to enhance nitrogen removal and reduce aeration energy consumption by controlling low DO levels (0.5-1.0 mg L(-1)) in a lab-scale anoxic-oxic reactor (V=66 L) treating real domestic wastewater at room temperature. Above 85% of nitrite accumulation ratio was steadily maintained during continuous operation period. The combined process improved the total nitrogen (TN) removal by about 20% in comparison to the traditional process via the nitrate pathway, and also reduced the specific aeration energy consumption by 35%. COD, ammonium and TN removal efficiencies were up to 86%, 94% and 75%, respectively. The process proved effective in achieving a steady LFB state, whereby sludge volume index between 150 and 250 mL g(-1) was sustained for long-term operation. The microbial community structure was analyzed by fluorescence in situ hybridization, which indicated ammonia-oxidizing bacteria out-competed nitrite-oxidizing bacteria. Moreover, the filaments Type 0041 and Microthrix parvicella proliferated with limited abundance. The results indicated the combination process of LFB and nitrogen removal via nitrite under low DO was a feasible solution for saving energy and enhancing nitrogen removal when treating domestic wastewater. PMID:23305749

Guo, Jianhua; Peng, Yongzhen; Yang, Xiong; Gao, Chundi; Wang, Shuying

2013-01-07

393

Synthesis and intracrystalline oxidation of nitrite-intercalated layered double hydroxides  

SciTech Connect

Nitrite-intercalated LDHs could be prepared by a two-stage process that involves coprecipitation in the presence of nitrite ions followed by stirring the product with excess of nitrite ions. The nitrite ion lies flat in these LDHs with its c{sub 2}-axis lying approximately perpendicular to the crystallographic c-axis. The interlayer nitrite ions in these LDHs could be quantitatively oxidized to nitrate ions using H{sub 2}O{sub 2} solution. In the LDHs thus obtained the nitrate ion lies flat with its c{sub 3}-axis parallel to the crystallographic c-axis (D{sub 3h} symmetry) in the interlayer region resulting in lower basal spacing. - Graphical abstract: Nitrite-intercalated LDHs could be prepared by a two-stage process that involves coprecipitation in the presence of nitrite ions followed by stirring the product with excess of nitrite ions. The interlayer nitrite ions in these LDHs could be quantitatively oxidized to nitrate ions.

Thomas, Nygil; Pradeep Kumar, G. [Materials Research Group, Department of Chemistry, St. Joseph's College, 36 Lalbagh Road, Bangalore 560027 (India); Rajamathi, Michael [Materials Research Group, Department of Chemistry, St. Joseph's College, 36 Lalbagh Road, Bangalore 560027 (India)], E-mail: mikerajamathi@rediffmail.com

2009-03-15

394

Ammonia Assimilation by Rhizobium Cultures and Bacteroids  

Microsoft Academic Search

SUMMARY The enzymes involved in the assimilation of ammonia by free-living cultures of Rhizobium spp. are glutamine synthetase (EC. 6.3. I. 2), glutamate synthase (L- glutamine : a-oxoglutarate amino transferase) and glutamate dehydrogenase (EC I.4. I.4). Under conditions of ammonia or nitrate limitation in a chemostat the assimilation of ammonia by cultures of R. leguminosarum, R. trifolii and R. japonicum

C. M. BROWN; M. J. DILWORTH

1975-01-01

395

Seasonal changes in abundance of ammonia-oxidizing archaea and ammonia-oxidizing bacteria and their nitrification in sand of an eelgrass zone.  

PubMed

Seasonal changes in the abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) within the sand of an eelgrass (Zostera marina) zone were examined by a quantitative PCR of both crenarchaeotal and betaproteobacterial ammonia monooxygenase alpha subunit (amoA) genes together with temperature and concentrations of ammonium, nitrite, and nitrate from May 2007 to June 2008 at Tanoura Bay, Shizuoka, Japan. The abundance of both amoAs in the sand between May and June 2007 and between January and March 2008 was 1.5 to 2 orders of magnitude higher than the 10(4) copies g(-1) of estimated amoA between September and December. Archaeal amoA was more diverse than betaproteobacterial amoA. Betaproteobacterial amoA clone libraries were dominated by Nitrosospira-like sequence types. An incubation experiment was conducted with sands collected in February 2008 and community structure was analyzed based on reverse-transcribed amoAs. RNA was extracted from sand incubated for 12 days at 30°C, 17 days at 20°C, and 80 days at 10°C. Different amoA clones were detected from in situ sand and incubated sand. This study reveals clear evidence of seasonal change in the abundance of AOA and AOB within the sand of an eelgrass zone. PMID:21566349

Ando, Yoshifumi; Nakagawa, Tatsunori; Takahashi, Reiji; Yoshihara, Kiyoshi; Tokuyama, Tatsuaki

2009-01-01

396

Nitrate Enhanced Microbial Cr(VI) Reduction-Final Report  

SciTech Connect

A major challenge for the bioremediation of radionuclides (i.e., uranium, technetium) and metals (i.e., Cr(VI), Hg) is the co-occurrence of nitrate as it can inhibit metal transformation. Denitrification (nitrate reduction to dinitrogen gas) is considered the most important ecological process. For many metal and metalloid reducing bacteria, however, ammonia is the end product through respiratory nitrate reduction (RNRA). The focus of this work was to determine how RNRA impacts Cr(VI) transformation. The goal was to elucidate the specific mechanism(s) that limits Cr(VI) reduction in the presence of nitrate and to use this information to develop strategies that enhance Cr(VI) reduction (and thus detoxification). Our central hypothesis is that nitrate impacts the biotransformation of metals and metalloids in three ways 1) as a competitive alternative electron acceptor (inhibiting transformation), 2) as a co-metabolite (i.e., concomitant reduction, stimulating transformation), and 3) as an inducer of specific proteins and pathways involved in oxidation/reduction reactions (stimulating transformation). We have identified three model organisms, Geobacter metallireducens (mechanism 1), Sulfurospirillum barnesii, (mechasism 2), and Desulfovibrio desulfuricans (mechanisms 3). Our specific aims were to 1) investigate the role of Cr(VI) concentration on the kinetics of both growth and reduction of nitrate, nitrite, and Cr(VI) in these three organisms; 2) develop a profile of bacterial enzymes involved in nitrate transformation (e.g., oxidoreductases) using a proteomic approach; 3) investigate the function of periplasmic nitrite reductase (Nrf) as a chromate reductase; and 4) develop a strategy to maximize microbial chromium reduction in the presence of nitrate. We found that growth on nitrate by G. metallireducens was inhibited by Cr(VI). Over 240 proteins were identified by LC/MS-MS. Redox active proteins, outer membrane heavy metal efflux proteins, and chemotaxis sensory proteins (Gmet_2478 and Gmet_1641) were up-regulated with exposure to Cr(VI). A nine-heme cytochrome C was purified that could reduce nitrite and could be oxidized by Cr(VI). For D. desulfuricans, we found that confirmed that Cr(VI) induced a prolonged lag period when Cr(VI) was reduced. Over three hundred proteins were unequivocally identified by LC/MS-MS and a significant number of down-regulated proteins for which the levels were changed >2 fold compared to control. Sulfite reductase levels were similar, however, nitrate and nitrite reductase were down-regulated. The supernatant of spent cultures was found to contain a filterable, heat stable compound that rapidly reduced Cr(VI). In addition, desulfoviridin was purified from nitrate grown cells and shown to have nitrite reductase activity that was inhibited by Cr(VI). For S. barnesii, periplasmic nitrate reductase (Nap), nitrite reductase (Nrf), and the metalloid reductase (Rar) were purified and characterized. The supernatant of spent cultures was also found to contain a filterable, heat stable compound that rapidly reduced Cr(VI) but that Rar also reduced Cr(VI). Our results from specific aims 1 through 3 indicate that for G. metallireducens, Cr(VI) inhibits nitrate respiration as it oxidizes cytochromes involved in nitrate respiration. Iron reduction is apparently not affected and the inhibitory affects of Cr(VI) may be attenuated by the addition of sufficient Fe(III) to generate Fe(II) that abiotically reduces the chromium. For S. barnesii, although the enzyme assays indicate that the components of the respiratory pathway for nitrate (e.g. Nap and Nrf) are inhibited by chromate, the organism has a mechanism to prevent this from actually occurring. Our current hypothesis is that the non-specific metalloid reductase (Rar) is providing resistance by reducing the Cr(VI). The strategy here would be to enhance its growth and metabolism in the natural setting. Lactate is a suitable electron donor for S. barnesii but other donors are possible. Although the version of the Phylochip used for monitoring the microb

John F. Stolz

2011-06-15

397

Electrocatalytic reduction of nitrate in sodium hydroxide solution in the presence of low-valent cobalt-cyclam species  

SciTech Connect

In concentrated NaOH solution nitrate and nitrite ions are efficiently reduced to a mixture of products including hydroxylamine and ammonia via an electrocatalytic process in the presence of cobalt complexes of 1,4,8,11-tetraazacyclotetradecane (cyclam). A key mechanistic role is proposed for Co{sup I}(cyclam)NO{sub 3}, which is generated in the diffusion layer at ca. -1.3 V vs SCE. The lack of dependent on pH of either the catalytic peak potential or the peak current indicates that metal hydride intermediate species are not involved in the initial steps of the reduction process. Both Co{sup I} and Co{sup III} intermediates in the nitrate reduction are detected in collection experiments with a gold ring-disk electrode. 18 refs., 8 figs., 2 tabs.

Li, Hulin; Anderson, W.C.; Chambers, J.Q. (Univ. of Tennessee, Knoxville (USA)); Hobbs, D.T. (E.I. du Pont de Nemours and Co., Inc., Aiken, SC (USA))

1989-03-08

398

Nitrite inhibition of denitrification by Pseudomonas fluorescens  

SciTech Connect

Using a pure culture of Pseudomonas fluorescens as a model system nitrite inhibition of denitrification was studied. A mineral media with acetate and nitrate as sole electron donor and acceptor, respectively, was used. Results obtained in continuous stirred-tank reactors (CSTR) operated at pH values between 6.6 and 7.8 showed that growth inhibition depended only on the nitrite undissociated fraction concentration (nitrous acid). A mathematical model to describe this dependence is put forward. The maximum nitrous acid concentration compatible with cell growth and denitrification activity was found to be 66 {mu}g N/L. Denitrification activity was partially associated with growth, as described by the Luedeking-Piret equation. However, when the freshly inoculated reactor was operated discontinuously, nitrite accumulation caused growth uncoupling from denitrification activity. The authors suggest that these results can be interpreted considering that (a) nitrous acid acts as a proton uncoupler; and (b) cultures continuously exposed to nitrous acid prevent the uncoupling effect but not the growth inhibition. Examination of the growth dependence on nitrite concentration at pH 7.0 showed that adapted cultures (growth on CSTR) are less sensitive to nitrous acid inhibition than the ones cultivated in batch.

Almeida, J.S.; Julio, S.M.; Reis, M.A.M. [FCT/UNL, Monte da Caparica (Portugal); Carrondo, M.J.T. [FCT/UNL, Monte da Caparica (Portugal)]|[Inst. de Biologia Experimental e Tecnologica, Oeiras (Portugal)

1995-05-05

399

NITRITE CONFERS PROTECTION AGAINST MYOCARDIAL INFARCTION: ROLE OF XANTHINE OXIDOREDUCTASE, NADPH OXIDASE AND KATP CHANNELS  

PubMed Central

Reduction of nitrite to nitric oxide during ischemia protects the heart against injury from ischemia/reperfusion. However the optimal dose of nitrite and the mechanisms underlying nitrite-induced cardioprotection are not known. We determined the ability of nitrite and nitrate to confer protection against myocardial infarction in two rat models of ischemia/reperfusion injury and the role of xanthine oxidoreductase, NADPH oxidase, nitric oxide synthase and KATP channels in mediating nitrite-induced cardioprotection. In vivo and in vitro rat models of myocardial ischemia/reperfusion injury were used to cause infarction. Hearts (n=6/group) were treated with nitrite or nitrate for 15 min prior to 30 min regional ischemia and 180 min reperfusion. Xanthine oxidoreductase activity was measured after 15 min aerobic perfusion and 30 min ischemia. Nitrite reduced myocardial necrosis and decline in ventricular function following ischemia/reperfusion in the intact and isolated rat heart in a dose or concentration-dependent manner with an optimal dose of 4 mg/kg in vivo and concentration of 10 ?M in vitro. Nitrate had no effect on protection. Reduction in infarction by nitrite was abolished by inhibition of flavoprotein reductases and the molybdenum site of xanthine oxidoreductase, and was associated with an increase in activity of xanthine dehydrogenase and xanthine oxidase during ischemia. Inhibition of nitric oxide synthase had no effect on nitrite-induced cardioprotection. Inhibition of NADPH oxidase and KATP channels abolished nitrite-induced cardioprotection. Nitrite but not nitrate protects against infarction by a mechanism involving xanthine oxidoreductase, NADPH oxidase and KATP channels.

Baker, John E.; Su, Jidong; Fu, Xiangping; Hsu, Anna; Gross, Garrett J.; Tweddell, James S.; Hogg, Neil

2009-01-01

400

Rapid abiotic transformation of nitrate in an acid forest soil  

Microsoft Academic Search

Nitrate immobilization into organic matter isthought to require catalysis by the enzymes ofsoil microorganisms. However, recent studiessuggest that nitrate added to soil isimmobilized rapidly and this process mayinclude abiotic pathways. We amended living andsterilized soil with 15N-labeled nitrateand nitrite to investigate biotic and abioticimmobilization. We report rapid transformationof nitrate in incubations of the O layer offorest soils that have been

DavidBryan Dail; Eric A. Davidson; Jon Chorover

2001-01-01

401

Controlling the nitrite:ammonium ratio in a SHARON reactor in view of its coupling with an Anammox process  

Microsoft Academic Search

The combined SHARON-Anammox process for treating wastewater streams with high ammonia load is the focus of this paper. In particular, partial nitritation in the SHARON reactor should be performed to such an extent that a nitrite:ammonium ratio is generated which is optimal for full conversion in an Anammox process. In the simulation studies performed in this contribution, the nitrite:ammonium ratio

E. I. P. Volcke; M. C. M. van Loosdrecht; P. A. Vanrolleghem

2006-01-01

402

Ammonia Synthesis  

Microsoft Academic Search

\\u000a Ammonia production is a very energy- and capital-intensive industry as it requires high temperature (400–500°C) and also high\\u000a pressure (150–300 bar) for its daily operations. Two moles of ammonia are obtained by reacting one mole of nitrogen and three\\u000a moles of hydrogen gases in the presence of conventional catalyst which is magnetite. The process to produce ammonia is known\\u000a as

Noorhana Yahya; Poppy Puspitasari; Krzysztof Koziol; Pavia Guiseppe

403

Assessment of N2O emission from a photobioreactor treating ammonia-rich swine wastewater digestate.  

PubMed

This study investigated the interactions between naturally occurring bacteria and the microalgae Chlorella vulgaris within a lab scale photobioreactor treating ammonia-rich swine wastewater digestate effluent. Nitrification and denitrification were assessed by targeting ammonia monoxygenases (amoA), nitrate (narG), nitrite (nirS), nitric oxide (norB) and nitrous oxide (nosZ) reductases genes. Oxygen produced from microalgae photosynthesis stimulated nitrification. Under limiting carbon availability (i.e., <1.44 for mg TOC/mg NO2-N and 1.72 for mg TOC/mg NO3-N), incomplete denitrification led to accumulation of NO2 and NO3. Significant N2O emission (up to 118?g N2O-N) was linked to NO2 metabolism in Chlorella. The addition of acetate as external carbon source recovered heterotrophic denitrification activity suppressing N2O emission. Effluent methane concentrations trapped within photobioreactor was removed concomitantly with ammonia. Overall, closed photobioreactors can be built to effectively remove nitrogen and mitigate simultaneously greenhouse gases emissions that would occur otherwise in open microalgae-based wastewater treatment systems. PMID:24128394

Mezzari, Melissa P; da Silva, Márcio L B; Nicoloso, Rodrigo S; Ibelli, Adriana M G; Bortoli, Marcelo; Viancelli, Aline; Soares, Hugo M

2013-09-26

404

Biochemical predetermination of the NO synthase and nitrite reductase components of the nitric oxide cycle.  

PubMed

This review presents some aspects of a concept of cellular evolution bearing a relationship to nitrate--nitrite respiration, the endosymbiosis theory, and the origin of NO synthase and nitrite reductase activity in heme-containing proteins. Analysis of structural and functional unity of the NO synthase and nitrite reductase systems suggests that these systems did not arise without any relation to evolutionarily ancient energetic systems of cells. The use of symmetry principles reveals commonalities among many electron transport chains which in the language of physics is called "invariance". This work also comparatively analyzes the nitric oxide cycle and the known nitrogen cycle. The ideas about evolution of the NO synthase and nitrite reductase systems developed here are clearly compatible with the endosymbiotic theory and the hypothesis that nitrate--nitrite respiration was a precursor of oxygen-dependent respiration. PMID:10381613

Reutov, V P

1999-05-01

405

Drivers of archaeal ammonia-oxidizing communities in soil.  

PubMed

Soil ammonia-oxidizing archaea (AOA) are highly abundant and play an important role in the nitrogen cycle. In addition, AOA have a significant impact on soil quality. Nitrite produced by AOA and further oxidized to nitrate can cause nitrogen loss from soils, surface and groundwater contamination, and water eutrophication. The AOA discovered to date are classified in the phylum Thaumarchaeota. Only a few archaeal genomes are available in databases. As a result, AOA genes are not well annotated, and it is difficult to mine and identify archaeal genes within metagenomic libraries. Nevertheless, 16S rRNA and comparative analysis of ammonia monooxygenase sequences show that soils can vary greatly in the relative abundance of AOA. In some soils, AOA can comprise more than 10% of the total prokaryotic community. In other soils, AOA comprise less than 0.5% of the community. Many approaches have been used to measure the abundance and diversity of this group including DGGE, T-RFLP, q-PCR, and DNA sequencing. AOA have been studied across different soil types and various ecosystems from the Antarctic dry valleys to the tropical forests of South America to the soils near Mount Everest. Different studies have identified multiple soil factors that trigger the abundance of AOA. These factors include pH, concentration of available ammonia, organic matter content, moisture content, nitrogen content, clay content, as well as other triggers. Land use management appears to have a major effect on the abundance of AOA in soil, which may be the result of nitrogen fertilizer used in agricultural soils. This review summarizes the published results on this topic and suggests future work that will increase our understanding of how soil management and edaphoclimatic factors influence AOA. PMID:22715335

Zhalnina, Kateryna; de Quadros, Patrícia Dörr; Camargo, Flavio A O; Triplett, Eric W

2012-06-15

406

Drivers of archaeal ammonia-oxidizing communities in soil  

PubMed Central

Soil ammonia-oxidizing archaea (AOA) are highly abundant and play an important role in the nitrogen cycle. In addition, AOA have a significant impact on soil quality. Nitrite produced by AOA and further oxidized to nitrate can cause nitrogen loss from soils, surface and groundwater contamination, and water eutrophication. The AOA discovered to date are classified in the phylum Thaumarchaeota. Only a few archaeal genomes are available in databases. As a result, AOA genes are not well annotated, and it is difficult to mine and identify archaeal genes within metagenomic libraries. Nevertheless, 16S rRNA and comparative analysis of ammonia monooxygenase sequences show that soils can vary greatly in the relative abundance of AOA. In some soils, AOA can comprise more than 10% of the total prokaryotic community. In other soils, AOA comprise less than 0.5% of the community. Many approaches have been used to measure the abundance and diversity of this group including DGGE, T-RFLP, q-PCR, and DNA sequencing. AOA have been studied across different soil types and various ecosystems from the Antarctic dry valleys to the tropical forests of South America to the soils near Mount Everest. Different studies have identified multiple soil factors that trigger the abundance of AOA. These factors include pH, concentration of available ammonia, organic matter content, moisture content, nitrogen content, clay content, as well as other triggers. Land use management appears to have a major effect on the abundance of AOA in soil, which may be the result of nitrogen fertilizer used in agricultural soils. This review summarizes the published results on this topic and suggests future work that will increase our understanding of how soil management and edaphoclimatic factors influence AOA.

Zhalnina, Kateryna; de Quadros, Patricia Dorr; Camargo, Flavio A. O.; Triplett, Eric W.

2012-01-01

407

Impact of free ammonia on anammox rates (anoxic ammonium oxidation) in a moving bed biofilm reactor.  

PubMed

Using a bench scale moving bed bioreactor (MBBR), the effect of free ammonia (FA, NH(3), the un-ionized form of ammonium NH(4)(+)) concentration on anoxic ammonium oxidation (anammox) was evaluated based on the volumetric nitrogen removal rate (NRR). Although, a detailed microbial analysis was not conducted, the major NRR observed was assumed to be by anammox, based on the nitrogen conversion ratios of nitrite to ammonium and nitrate to ammonium. Since the concentration of free ammonia as a proportion of the total ammonia concentration is pH-dependent, the impact of changing the operating pH from 6.9 to 8.2, was investigated under constant nitrogen loading conditions during continuous reactor operation. Furthermore, the effect of sudden nitrogen load changes was investigated under constant pH conditions. Batch tests were conducted to determine the immediate response of the anammox consortium to shifts in pH and FA concentrations. It was found that FA was inhibiting NRR at concentrations exceeding 2 mg N L(-1). In the pH range 7-8, the decrease in anammox activity was independent of pH and related only to the concentration of FA. Nitrite concentrations of up to 120 mg N L(-1) did not negatively affect NRR for up to 3.5 h. It was concluded that a stable NRR in a moving bed biofilm reactor depended on maintaining FA concentrations below 2 mg N L(-1) when the pH was maintained between 7 and 8. PMID:22483855

Jaroszynski, L W; Cicek, N; Sparling, R; Oleszkiewicz, J A

2012-04-06

408

Nitrite Transport Activity of the ABC-Type Cyanate Transporter of the Cyanobacterium Synechococcus elongatus?  

PubMed Central

In addition to the ATP-binding cassette (ABC)-type nitrate/nitrite-bispecific transporter, which has a high affinity for both substrates (Km, ?1 ?M), Synechococcus elongatus has an active nitrite transport system with an apparent Km (NO2?) value of 20 ?M. We found that this activity depends on the cynABD genes, which encode a putative cyanate (NCO?) ABC-type transporter. Accordingly, nitrite transport by CynABD was competitively inhibited by NCO? with a Ki value of 0.025 ?M. The transporter was induced under conditions of nitrogen deficiency, and the induced cells showed a Vmax value of 11 to 13 ?mol/mg of chlorophyll per h for cyanate or nitrite, which could supply ?30% of the amount of nitrogen required for optimum growth. Its relative specificity for the substrates and regulation at transcriptional and posttranslational levels suggested that the physiological role of the bispecific cyanate/nitrite transporter in S. elongatus is to allow nitrogen-deficient cells to assimilate low concentrations of cyanate in the medium. Its contribution to nitrite assimilation was significant in a mutant lacking the ABC-type nitrate/nitrite transporter, suggesting a possible role for CynABD in nitrite assimilation by cyanobacterial species that lack another high-affinity mechanism(s) for nitrite transport.

Maeda, Shin-ichi; Omata, Tatsuo

2009-01-01

409

Gastroprotective and blood pressure lowering effects of dietary nitrate are abolished by an antiseptic mouthwash  

Microsoft Academic Search

Recently, it has been suggested that the supposedly inert nitrite anion is reduced in vivo to form bioactive nitric oxide with physiological and therapeutic implications in the gastrointestinal and cardiovascular systems. Intake of nitrate-rich food such as vegetables results in increased levels of circulating nitrite in a process suggested to involve nitrate-reducing bacteria in the oral cavity. Here we investigated

Joel Petersson; Mattias Carlström; Olof Schreiber; Mia Phillipson; Gustaf Christoffersson; Annika Jägare; Stefan Roos; Emmelie Å. Jansson; A. Erik G. Persson; Jon O. Lundberg; Lena Holm

2009-01-01

410

Liquid Ammonia  

Microsoft Academic Search

This is a review of the use of liquid ammonia as a solvent for chemical processes. Among the subjects covered are the physical properties of the solvent that defines it as “water like.” The physical and chemical processes associated with the formation of solutions and the properties of those solutions are also convered. Included is a discussion of metal?ammonia solutions,

J. J. Lagowski

2007-01-01

411

Nitrate in Ground Waters of the United States: Contrasting Scales and Processes  

NASA Astrophysics Data System (ADS)

Nitrate is one of the most ubiquitous compounds in ground water. Studies conducted during 1992 - 1995 by the U.S. Geological Survey's National Water Quality Assessment (NAWQA) Program detected nitrate in 71% of shallow ground water samples, more than 13 times as often as organic nitrogen, ammonia, nitrite, and orthophosphate (based on a common detection threshold of 0.2 mg/L). Nitrate commonly occurs in mixtures with other contaminants. Mixtures of "anthropogenic" nitrate (>3 mg/L as N), atrazine, and deethylatrazine were among the most frequently occurring mixtures in ground water samples from 1,497 domestic and public supply wells. The samples were analyzed for nitrate, 83 pesticides, and 60 volatile organic compounds. Elevated nitrate concentration in ground water has been associated with adverse health effects. Interpretive studies conducted at contrasting spatial scales reveal different processes influencing nitrate behavior in ground water. At the national scale, an empirical model indicates that leaching and water-table position influence nitrate concentration in shallow ground water (typically <5 m deep). The probability of nitrate contamination is greater in areas with high nitrogen loading and well-drained soils overlying unconsolidated sand and gravel deposits. Median nitrate concentration for wells grouped by mapped probability region increases from 0.24 to 8.3 mg/L as the predicted probability of nitrate exceeding 4 mg/L increases from 0.17 or less to >0.83. With these shallow ground-water data, nitrate contamination risk increases with increasing depth to ground water because of reduced denitrification potential. Denitrification commonly occurs under anoxic conditions in areas with very shallow depth to ground water (i.e., high water-table position). A regional study indicates that nitrate reduction and calcite dissolution processes influence nitrate concentration in ground waters of the southeastern United States. Water and sediment of the North Carolina-Virginia Coastal Plain contain sufficient organic carbon (4.2 mg/L) for bacterial reduction of nitrate to nitrogen gas, and median nitrate concentration in the area is <0.05 mg/L. Median depth to water in the area is about 2 m. In contrast, nitrate concentration is high (median = 4.6 mg/L) in ground water samples from the Great Valley Carbonate area of the Potomac River Basin. Acidic water creates solution channels in carbonate rocks that readily convey nitrate and other contaminants to ground water. Nitrate concentration is related to land use and point estimates of ground-water recharge in a subregional scale study conducted in a North Atlantic Coastal Plain aquifer in southern New Jersey. The recharge estimates are based on pedotransfer functions that relate water-retention parameters to measured soil texture and bulk density. Ranked nitrate concentration was grouped by low (29.1 cm/yr or less) and high (>29.1 cm/yr) recharge categories in a two-way analysis of variance that compensated for land use. Nitrate concentration is significantly lower in the high recharge category (p = 0.024), suggesting possible dilution by infiltrating water or by bulk flow within the aquifer. This is in contrast to the leaching process indicated by the national-scale model. Although median depth to ground water in the area is only about 1 m, median nitrate concentration is 5.5 mg/L in the low recharge category and 2.4 mg/L in the high recharge category, irrespective of land use. The high nitrate concentration relative to ground waters of the North Carolina-Virginia Coastal Plain indicates that denitrification is not a mitigating factor in the southern New Jersey study area.

Nolan, B. T.

2002-12-01

412

Nitrate contamination of drinking water: Evaluation of genotoxic risk in human populations  

Microsoft Academic Search

Nitrate contamination of drinking water implies a genotoxic risk to man due to endogenous formation of carcinogenic N-nitroso compounds from nitrate-derived nitrite. Thus far, epidemiological studies have presented conflicting results on the relation of drinking water nitrate levels with gastric cancer incidence. This uncertainty becomes of relevance in view of the steadily increasing nitrate levels in regular drinking water supplies.

J. C. S. Kleinjans; H. J. Albering; A. Marx; J. M. S. van Maanen; B. van Agen; F. ten Hoor; G. M. H. Swaen; P. L. J. M. Mertens

1991-01-01

413

Kinetic Explanation for Accumulation of Nitrite, Nitric Oxide, and Nitrous Oxide During Bacterial Denitrification †  

PubMed Central

The kinetics of denitrification and the causes of nitrite and nitrous oxide accumulation were examined in resting cell suspensions of three denitrifiers. An Alcaligenes species and a Pseudomonas fluorescens isolate characteristically accumulated nitrite when reducing nitrate; a Flavobacterium isolate did not. Nitrate did not inhibit nitrite reduction in cultures grown with tungstate to prevent formation of an active nitrate reductase; rather, accumulation of nitrite seemed to depend on the relative rates of nitrate and nitrite reduction. Each isolate rapidly reduced nitrous oxide even when nitrate or nitrite had been included in the incubation mixture. Nitrate also did not inhibit nitrous oxide reduction in Alcaligenes odorans, an organism incapable of nitrate reduction. Thus, added nitrate or nitrite does not always cause nitrous oxide accumulation, as has often been reported for denitrifying soils. All strains produced small amounts of nitric oxide during denitrification in a pattern suggesting that nitric oxide was also under kinetic control similar to that of nitrite and nitrous oxide. Apparent Km values for nitrate and nitrite reduction were 15 ?M or less for each isolate. The Km value for nitrous oxide reduction by Flavobacterium sp. was 0.5 ?M. Numerical solutions to a mathematical model of denitrification based on Michaelis-Menten kinetics showed that differences in reduction rates of the nitrogenous compounds were sufficient to account for the observed patterns of nitrite, nitric oxide, and nitrous oxide accumulation. Addition of oxygen inhibited gas production from 13NO3? by Alcaligenes sp. and P. fluorescens, but it did not reduce gas production by Flavobacterium sp. However, all three isolates produced higher ratios of nitrous oxide to dinitrogen as the oxygen tension increased. Inclusion of oxygen in the model as a nonspecific inhibitor of each step in denitrification resulted in decreased gas production but increased ratios of nitrous oxide to dinitrogen, as observed experimentally. The simplicity of this kinetic model of denitrification and its ability to unify disparate observations should make the model a useful guide in research on the physiology of denitrifier response to environmental effectors.

Betlach, Michael R.; Tiedje, James M.

1981-01-01

414

Methemoglobinemia: nitrate toxicity in rural America  

SciTech Connect

Nitrates are frequently found in vegetables and ground water. Nitrate levels in ground water have increased over the past two decades because of the heightened use of nitrogenous fertilizers. Following ingestion, nitrates are converted to nitrites by fecal organisms. Nitrites are absorbed and form methemoglobin, which interferes with the oxygen-carrying capacity of hemoglobin. Infants are particularly susceptible to nitrate poisoning because fetal hemoglobin is more readily oxidized to methemoglobin. In infants, the most common source of nitrate exposure is well water, which is mixed with infant formula. Affected infants may present with asymptomatic cyanosis, which can progress to dyspnea and lethargy or coma. Blood methemoglobin concentrations are elevated. Treatment consists of the administration of oxygen and intravenous and oral methylene blue.24 references.

Kross, B.C.; Ayebo, A.D.; Fuortes, L.J. (University of Iowa College of Medicine, Iowa City (United States))

1992-07-01

415

Magnetic Resonance Study of the Transmembrane Nitrite Diffusion  

PubMed Central

Nitrite (NO2-), being a product of metabolism of both nitric oxide (NO•) and nitrate (NO3-), can accumulate in tissues and regenerate NO• by several mechanisms. The effect of NO2- on ischemia/reperfusion injury was also reported. Nevertheless, the mechanisms of intracellular NO2- accumulation are poorly understood. We suggested significant role of nitrite penetration through biological membranes in the form of undissociated nitrous acid (HNO2). This hypothesis has been tested using large unilamellar phosphatidylcholine liposomes and several spectroscopic techniques. HNO2 transport across the phospholipid bilayer of liposomes facilitates proton transfer resulting in intraliposomal acidification, which was measured using pH-sensitive probes. NO2--mediated intraliposomal acidification was confirmed by EPR spectroscopy using membrane-impermeable pH-sensitive nitroxide, 2,2,5,5-tetramethyl-1-oxyl-2,5-dihydro-1H-imidazol-3-ium-4-yl)-aminomethanesulfonic acid (pK 5.25), and by 31P-NMR spectroscopy using inorganic phosphate (pK 6.9). Nitrite accumulates inside liposomes in concentration exceeding its concentration in the bulk solution, when initial transmembrane pH gradient (alkaline inside) is applied. Intraliposomal accumulation of NO2- was observed by direct measurement using chemiluminescence technique. Perfusion of isolated rat hearts with buffer containing 4 ?M NO2- was performed. The nitrite concentrations in the effluent and in the tissue, measured after 1 minute perfusion were close, supporting fast penetration of the nitrite through the tissue. Measurements of the nitrate/nitrate showed that total concentration of NOx in myocardium increased from initial 7.8 ?M to 24.7 ?M after nitrite perfusion. Physiological significance of passive transmembrane transport of NO2- and its coupling with intraliposomal acidification are discussed.

Samouilov, A.; Woldman, Ya.Yu.; Zweier, J.L.; Khramtsov, V.V.

2009-01-01

416

Ammonia (GCMP)  

NSDL National Science Digital Library

Ammonia fountain: this is a resource in the collection "General Chemistry Multimedia Problems". In an ammonia fountain, a flask is filled with ammonia gas. A tube from the flask extends into a pan of water that contains phenolphthalein. When a rubber bulb full of water is squeezed, the water squirts into the flask. Water from the pan then is pushed into the flask and the indicator changes color. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

417

Hexaheme nitrite reductase from Desulfovibrio desulfuricans  

SciTech Connect

Moessbauer and EPR spectroscopy were used to characterize the heme prosthetic groups of the nitrite reductase isolated from Desulfovibrio desulfuricans (ATCC 27774), which is a membrane-bound multiheme cytochrome capable of catalyzing the 6-electron reduction of nitrite to ammonia. At pH 7.6, the as-isolated enzyme exhibited a complex EPR spectrum consisting of a low-spin ferric heme signal at g = 2.96, 2.28, and 1.50 plus several broad resonances indicative of spin-spin interactions among the heme groups. EPR redox titration studies revealed yet another low-spin ferric heme signal at g = 3.2 and 2.14 (the third g value was undetected) and the presence of a high-spin ferric heme. Moessbauer measurements demonstrated further that this enzyme contained six distinct heme groups: one high-spin (S = 5/2) and five low-spin (S = 1/2) ferric hemes. Characteristic hyperfine parameters for all six hemes were obtained through a detailed analysis of the Moessbauer spectra. D. desulfuricans nitrite reductase can be reduced by chemical reductants, such as dithionite or reduced methyl viologen, or by hydrogenase under hydrogen atmosphere. Addition of nitrite to the fully reduced enzyme reoxidized all five low-spin hemes to their ferric states. The high-spin heme, however, was found to complex NO, suggesting that the high-spin heme could be the substrate binding site and that NO could be an intermediate present in an enzyme-bound form.

Costa, C.; Moura, J.J.G.; Moura, I. (Centro de Tecnologia Quimica e Biologica, Oeiras (Portugal) Univ. Nova de Lisboa, Oeiras (Portugal)); Liu, M.Y.; Peck, H.D. Jr.; LeGall, J. (Univ. of Georgia, Athens (United States)); Wang, Yaning; Huynh, B.H. (Emory Univ., Atlanta, GA (United States))

1990-08-25