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Sample records for acidified sodium nitrite

  1. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium nitrite and potassium nitrite. 181.34... nitrite and potassium nitrite. Sodium nitrite and potassium nitrite are subject to prior sanctions issued... without sodium or potassium nitrate, in the curing of red meat and poultry products....

  2. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium nitrite and potassium nitrite. 181.34...-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium... fixatives and preservative agents, with or without sodium or potassium nitrate, in the curing of red...

  3. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium nitrite and potassium nitrite. 181.34...-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium... fixatives and preservative agents, with or without sodium or potassium nitrate, in the curing of red...

  4. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrite and potassium nitrite. 181.34...-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium... fixatives and preservative agents, with or without sodium or potassium nitrate, in the curing of red...

  5. 21 CFR 181.34 - Sodium nitrite and potassium nitrite.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium nitrite and potassium nitrite. 181.34...-Sanctioned Food Ingredients § 181.34 Sodium nitrite and potassium nitrite. Sodium nitrite and potassium... fixatives and preservative agents, with or without sodium or potassium nitrate, in the curing of red...

  6. 21 CFR 173.325 - Acidified sodium chlorite solutions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Acidified sodium chlorite solutions. 173.325... § 173.325 Acidified sodium chlorite solutions. Acidified sodium chlorite solutions may be safely used in... solution of sodium chlorite (CAS Reg. No. 7758-19-2) with any generally recognized as safe (GRAS) acid....

  7. 21 CFR 173.325 - Acidified sodium chlorite solutions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Acidified sodium chlorite solutions. 173.325... HUMAN CONSUMPTION Specific Usage Additives § 173.325 Acidified sodium chlorite solutions. Acidified sodium chlorite solutions may be safely used in accordance with the following prescribed conditions:...

  8. 21 CFR 173.325 - Acidified sodium chlorite solutions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acidified sodium chlorite solutions. 173.325... HUMAN CONSUMPTION Specific Usage Additives § 173.325 Acidified sodium chlorite solutions. Acidified sodium chlorite solutions may be safely used in accordance with the following prescribed conditions:...

  9. 21 CFR 573.700 - Sodium nitrite.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium nitrite. 573.700 Section 573.700 Food and... Listing § 573.700 Sodium nitrite. Sodium nitrite may be safely used in canned pet food containing meat and... byproducts so that the level of sodium nitrite does not exceed 20 parts per million. (b) To assure safe...

  10. 21 CFR 573.700 - Sodium nitrite.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium nitrite. 573.700 Section 573.700 Food and... Listing § 573.700 Sodium nitrite. Sodium nitrite may be safely used in canned pet food containing meat and... byproducts so that the level of sodium nitrite does not exceed 20 parts per million. (b) To assure safe...

  11. 21 CFR 573.700 - Sodium nitrite.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium nitrite. 573.700 Section 573.700 Food and... Listing § 573.700 Sodium nitrite. Sodium nitrite may be safely used in canned pet food containing meat and... byproducts so that the level of sodium nitrite does not exceed 20 parts per million. (b) To assure safe...

  12. 21 CFR 573.700 - Sodium nitrite.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium nitrite. 573.700 Section 573.700 Food and... Listing § 573.700 Sodium nitrite. Sodium nitrite may be safely used in canned pet food containing meat and... byproducts so that the level of sodium nitrite does not exceed 20 parts per million. (b) To assure safe...

  13. 21 CFR 573.700 - Sodium nitrite.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium nitrite. 573.700 Section 573.700 Food and... Listing § 573.700 Sodium nitrite. Sodium nitrite may be safely used in canned pet food containing meat and... byproducts so that the level of sodium nitrite does not exceed 20 parts per million. (b) To assure safe...

  14. 21 CFR 173.325 - Acidified sodium chlorite solutions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HUMAN CONSUMPTION Specific Usage Additives § 173.325 Acidified sodium chlorite solutions. Acidified...., College Park, MD 20740, or may be examined at the Center for Food Safety and Applied Nutrition's...

  15. 21 CFR 172.175 - Sodium nitrite.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium nitrite. 172.175 Section 172.175 Food and... Preservatives § 172.175 Sodium nitrite. The food additive sodium nitrite may be safely used in or on specified... follows: (1) As a color fixative in smoked cured tunafish products so that the level of sodium...

  16. 21 CFR 172.175 - Sodium nitrite.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium nitrite. 172.175 Section 172.175 Food and... Preservatives § 172.175 Sodium nitrite. The food additive sodium nitrite may be safely used in or on specified... follows: (1) As a color fixative in smoked cured tunafish products so that the level of sodium...

  17. 21 CFR 172.175 - Sodium nitrite.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium nitrite. 172.175 Section 172.175 Food and... Preservatives § 172.175 Sodium nitrite. The food additive sodium nitrite may be safely used in or on specified... follows: (1) As a color fixative in smoked cured tunafish products so that the level of sodium...

  18. 21 CFR 172.175 - Sodium nitrite.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrite. 172.175 Section 172.175 Food and... Preservatives § 172.175 Sodium nitrite. The food additive sodium nitrite may be safely used in or on specified... follows: (1) As a color fixative in smoked cured tunafish products so that the level of sodium...

  19. 21 CFR 172.175 - Sodium nitrite.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium nitrite. 172.175 Section 172.175 Food and... PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.175 Sodium nitrite. The food additive sodium nitrite may be safely used in or on specified foods in accordance with...

  20. Inhibition Of Washed Sludge With Sodium Nitrite

    SciTech Connect

    Congdon, J. W.; Lozier, J. S.

    2012-09-25

    This report describes the results of electrochemical tests used to determine the relationship between the concentration of the aggressive anions in washed sludge and the minimum effective inhibitor concentration. Sodium nitrate was added as the inhibitor because of its compatibility with the DWPF process. A minimum of 0.05M nitrite is required to inhibit the washed sludge simulant solution used in this study. When the worst case compositions and safety margins are considered, it is expected that a minimum operating limit of nearly 0.1M nitrite will be specified. The validity of this limit is dependent on the accuracy of the concentrations and solubility splits previously reported. Sodium nitrite additions to obtain 0.1M nitrite concentrations in washed sludge will necessitate the additional washing of washed precipitate in order to decrease its sodium nitrite inhibitor requirements sufficiently to remain below the sodium limits in the feed to the DWPF. Nitrite will be the controlling anion in "fresh" washed sludge unless the soluble chloride concentration is about ten times higher than predicted by the solubility splits. Inhibition of "aged" washed sludge will not be a problem unless significant chloride dissolution occurs during storage. It will be very important tomonitor the composition of washed sludge during processing and storage.

  1. Severe Methemoglobinemia due to Sodium Nitrite Poisoning

    PubMed Central

    Hayakawa, Mineji; Gando, Satoshi

    2016-01-01

    Case. We report a case of severe methemoglobinemia due to sodium nitrite poisoning. A 28-year-old man was brought to our emergency department because of transient loss of consciousness and cyanosis. He was immediately intubated and ventilated with 100% oxygen. A blood test revealed a methemoglobin level of 92.5%. Outcome. We treated the patient with gastric lavage, activated charcoal, and methylene blue (2 mg/kg) administered intravenously. Soon after receiving methylene blue, his cyanosis resolved and the methemoglobin level began to decrease. After relocation to the intensive care unit, his consciousness improved and he could recall ingesting approximately 15 g sodium nitrite about 1 hour before he was brought to our hospital. The patient was discharged on day 7 without neurologic impairment. Conclusion. Severe methemoglobinemia may be fatal. Therefore, accurate diagnosis of methemoglobinemia is very important so that treatment can be started as soon as possible. PMID:27563472

  2. Nitrite addition to acidified sludge significantly improves digestibility, toxic metal removal, dewaterability and pathogen reduction

    NASA Astrophysics Data System (ADS)

    Du, Fangzhou; Keller, Jürg; Yuan, Zhiguo; Batstone, Damien J.; Freguia, Stefano; Pikaar, Ilje

    2016-12-01

    Sludge management is a major issue for water utilities globally. Poor digestibility and dewaterability are the main factors determining the cost for sludge management, whereas pathogen and toxic metal concentrations limit beneficial reuse. In this study, the effects of low level nitrite addition to acidified sludge to simultaneously enhance digestibility, toxic metal removal, dewaterability and pathogen reduction were investigated. Waste activated sludge (WAS) from a full-scale waste water treatment plant was treated at pH 2 with 10 mg NO2‑-N/L for 5 h. Biochemical methane potential tests showed an increase in the methane production of 28%, corresponding to an improvement from 247 ± 8 L CH4/kg VS to 317 ± 1 L CH4/kg VS. The enhanced removal of toxic metals further increased the methane production by another 18% to 360 ± 6 L CH4/kg VS (a total increase of 46%). The solids content of dewatered sludge increased from 14.6 ± 1.4% in the control to 18.2 ± 0.8%. A 4-log reduction for both total coliforms and E. coli was achieved. Overall, this study highlights the potential of acidification with low level nitrite addition as an effective and simple method achieving multiple improvements in terms of sludge management.

  3. Nitrite addition to acidified sludge significantly improves digestibility, toxic metal removal, dewaterability and pathogen reduction

    PubMed Central

    Du, Fangzhou; Keller, Jürg; Yuan, Zhiguo; Batstone, Damien J.; Freguia, Stefano; Pikaar, Ilje

    2016-01-01

    Sludge management is a major issue for water utilities globally. Poor digestibility and dewaterability are the main factors determining the cost for sludge management, whereas pathogen and toxic metal concentrations limit beneficial reuse. In this study, the effects of low level nitrite addition to acidified sludge to simultaneously enhance digestibility, toxic metal removal, dewaterability and pathogen reduction were investigated. Waste activated sludge (WAS) from a full-scale waste water treatment plant was treated at pH 2 with 10 mg NO2−-N/L for 5 h. Biochemical methane potential tests showed an increase in the methane production of 28%, corresponding to an improvement from 247 ± 8 L CH4/kg VS to 317 ± 1 L CH4/kg VS. The enhanced removal of toxic metals further increased the methane production by another 18% to 360 ± 6 L CH4/kg VS (a total increase of 46%). The solids content of dewatered sludge increased from 14.6 ± 1.4% in the control to 18.2 ± 0.8%. A 4-log reduction for both total coliforms and E. coli was achieved. Overall, this study highlights the potential of acidification with low level nitrite addition as an effective and simple method achieving multiple improvements in terms of sludge management. PMID:28004811

  4. Substitution of Oxides of Nitrogen for Sodium Nitrite

    SciTech Connect

    Yeager, C.J.

    2001-08-22

    The purpose of this report is to discuss the chemistry of nitrous acid, the Savannah River Plant application of nitrogen, environmental effects, and outline a development program for nitrogen replacement of sodium nitrite.

  5. 77 FR 71006 - Sodium Nitrite Injection and Sodium Thiosulfate Injection Drug Products Labeled for the Treatment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-28

    ... HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2012-N-1134 Sodium Nitrite Injection and Sodium Thiosulfate Injection Drug Products Labeled for the Treatment of Cyanide Poisoning; Enforcement... products containing sodium nitrite labeled for the treatment of cyanide poisoning and unapproved...

  6. Effect of sodium ascorbate and sodium nitrite on protein and lipid oxidation in dry fermented sausages.

    PubMed

    Berardo, A; De Maere, H; Stavropoulou, D A; Rysman, T; Leroy, F; De Smet, S

    2016-11-01

    The effects of sodium nitrite and ascorbate on lipid and protein oxidation were studied during the ripening process of dry fermented sausages. Samples were taken at day 0, 2, 8, 14, 21 and 28 of ripening to assess lipid (malondialdehyde) and protein (carbonyls and sulfhydryl groups) oxidation. Sodium ascorbate and nitrite were separately able to reduce the formation of malondialdehyde. Their combined addition resulted in higher amounts of carbonyl compounds compared to their separate addition or the treatment without any of both compounds. Moreover, sodium nitrite limited the formation of γ-glutamic semialdehyde whereas sodium ascorbate showed a pro-oxidant effect. A loss of thiol groups was observed during ripening, which was not affected by the use of sodium ascorbate nor sodium nitrite. In conclusion, sodium nitrite and ascorbate affected protein and lipid oxidation in different manners. The possible pro-oxidant effect of their combined addition on carbonyl formation might influence the technological and sensory properties of these products.

  7. Hydrogen sulfide poisoning: an antidotal role for sodium nitrite?

    PubMed

    Hall, A H; Rumack, B H

    1997-06-01

    In 2 separate incidents, 6 patients were poisoned with hydrogen sulfide (H2S) in sewer gas. In the first incident, mixing acid- and sodium hydroxide-based drain cleaners in a confined space resulted in 4 poisonings and 2 deaths. Three would-be rescuers were seriously poisoned and 1 died. Two survivors had neurological sequelae. Sodium nitrite appeared to have some clinical efficacy in 1 case. The second incident involved 2 patients working on a pump in a sewage pond. A patient lying on a raft close to the pond surface was seriously poisoned; sodium nitrite was clinically efficacious and this patient survived without developing neurological sequelae. Sodium nitrite deserves further clinical study as a potential H2S antidote.

  8. Antidotal action of sodium nitrite and sodium thiosulfate against cyanide poisoning. (Reannouncement with new availability information)

    SciTech Connect

    Baskin, S.I.; Horowitz, A.M.; Nealley, E.W.

    1992-04-01

    The combination of sodium thiosulfate and sodium nitrite has been used in the United States since the 1930s as the primary antidote for cyanide intoxication. Although this combination was shown to exhibit much greater efficacy than either ingredient alone, the two compounds could not be used prophylactically because each exhibits a number of side effects. This review discusses the pharmacodynamics, pharmacokinetics, and toxicology of the individual agents, and their combination....Cyanide, Blood agent, Chemical warfare agents, Antidotes, Sodium nitrite, Sodium thiosulfate.

  9. Final Feasibility Report on Chemical Treatment of Sodium Nitrite Wastewater

    DTIC Science & Technology

    1992-03-01

    hydroblasting waste - water. The removal of heavy metals was equally successful, an approach which resulted in reducing nearly all the ions to the discharge...wastewaters to nitrogen gas. In addition to sodium nitrite, the waste stream also includes various heavy metals in ionic form. The heavy metal ions, namely...cadmium, copper, nickel, chromium, lead, and zinc, are regulated by the EPA and several states as toxic wastes . When boiler nitrite wastewater is

  10. Solubility of sodium tungstate in nitrate-nitrite melts

    SciTech Connect

    Yurkinskii, V.P.; Firsova, E.G.; Morachevskii, A.G.; Sazanova, O.B.

    1988-10-10

    Nitrate melts are employed as electrolytes for the electrochemical oxidation of tungsten. The authors studied the solubility of sodium tungstate in a number of nitrate-nitrite melts. The investigations were carried out in individual melts of NaNO/sub 3/ and NaNO/sub 2/ and in LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/ and NaNO/sub 3/-KNO/sub 3/ eutectic mixtures in the 440-690 K temperature range in an atmosphere of argon. The solubility of sodium tungstate increases slightly upon the transition from an LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/ melt to an NaNO/sub 3/-KNO/sub 3/ melt. The solubility of Na/sub 2/WO/sub 4/ in sodium nitrite is considerably higher than that in sodium nitrate.

  11. 78 FR 39316 - Sodium Nitrite From China and Germany; Institution of Five-Year Reviews

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-01

    ... (Review)] Sodium Nitrite From China and Germany; Institution of Five-Year Reviews AGENCY: United States... determine whether revocation of the antidumping and countervailing duty orders on sodium nitrite from China and the antidumping duty order on sodium nitrite from Germany would be likely to lead to...

  12. 21 CFR 172.177 - Sodium nitrite used in processing smoked chub.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium nitrite used in processing smoked chub. 172... FOOD FOR HUMAN CONSUMPTION Food Preservatives § 172.177 Sodium nitrite used in processing smoked chub. The food additive sodium nitrite may be safely used in combination with salt (NaCl) to aid...

  13. UV-induced Lactobacillus gasseri mutants resisting sodium chloride and sodium nitrite for meat fermentation.

    PubMed

    Arihara, K; Itoh, M

    2000-06-01

    Lactobacillus gasseri, one of the predominant lactobacilli in human intestinal tracts, is utilized for probiotics and dairy starter cultures. However, since L. gasseri is relatively sensitive to sodium chloride and sodium nitrite (essential compounds for meat products), it is difficult to utilize this species for conventional fermented meat products. In this study, efforts were directed to generate mutants of L. gasseri resisting sodium chloride and sodium nitrite. UV irradiation of the strain of L. gasseri JCM1131(T) generated several mutants resisting these compounds. A mutant strain 1131-M8 demonstrated satisfactory growth in meat containing 3.3% sodium chloride and 200 ppm sodium nitrite. Although proteins extracted from the cell surface of 1131-M8 were slightly different from those of the original strain, other biochemical characteristics of both strains were indistinguishable. These results suggest that the L. gasseri mutant obtained in this study could be utilized as a starter culture to develop probiotic meat products.

  14. Anaerobic killing of mucoid Pseudomonas aeruginosa by acidified nitrite derivatives under cystic fibrosis airway conditions

    PubMed Central

    Yoon, Sang Sun; Coakley, Ray; Lau, Gee W.; Lymar, Sergei V.; Gaston, Benjamin; Karabulut, Ahmet C.; Hennigan, Robert F.; Hwang, Sung-Hei; Buettner, Garry; Schurr, Michael J.; Mortensen, Joel E.; Burns, Jane L.; Speert, David; Boucher, Richard C.; Hassett, Daniel J.

    2006-01-01

    Mucoid, mucA mutant Pseudomonas aeruginosa cause chronic lung infections in cystic fibrosis (CF) patients and are refractory to phagocytosis and antibiotics. Here we show that mucoid bacteria perish during anaerobic exposure to 15 mM nitrite (NO2–) at pH 6.5, which mimics CF airway mucus. Killing required a pH lower than 7, implicating formation of nitrous acid (HNO2) and NO, that adds NO equivalents to cellular molecules. Eighty-seven percent of CF isolates possessed mucA mutations and were killed by HNO2 (3-log reduction in 4 days). Furthermore, antibiotic-resistant strains determined were also equally sensitive to HNO2. More importantly, HNO2 killed mucoid bacteria (a) in anaerobic biofilms; (b) in vitro in ultrasupernatants of airway secretions derived from explanted CF patient lungs; and (c) in mouse lungs in vivo in a pH-dependent fashion, with no organisms remaining after daily exposure to HNO2 for 16 days. HNO2 at these levels of acidity and NO2– also had no adverse effects on cultured human airway epithelia in vitro. In summary, selective killing by HNO2 may provide novel insights into the important clinical goal of eradicating mucoid P. aeruginosa from the CF airways. PMID:16440061

  15. Evaluation of sodium bisulphate and phosphoric acid as urine acidifiers for cats.

    PubMed

    Spears, Julie K; Grieshop, Christine M; Fahey, G C

    2003-10-01

    Eighteen cats were used to compare the urine acidifying properties of sodium bisulphate to phosphoric acid. Acidifying agents were added at one of three concentrations (0.4, 0.6, or 0.8%, as-is basis). Cats were offered a commercial diet to determine basal urinary pH, and then again for a 1 week period between blocks 1 and 2. Cats were acclimated to the diets for 6 days, and urine samples were collected on day 7 at 0, 4, and 8 h postfeeding to obtain pre- and postprandial urinary pH. Intakes of diets containing sodium bisulphate tended (P < 0.07) to be lower than intakes of diets containing phosphoric acid. Cats consuming the 0.8% phosphoric acid diet had higher (P < 0.05) food intakes than cats consuming either the 0.4 or 0.6% phosphoric acid-containing diets. There was significant (P = 0.01) linear and quadratic response for food intake in cats consuming the sodium bisulphate-containing diet. Cats consuming the 0.4 and 0.8% phosphoric acid-containing diets tended (P = 0.07) to have higher water intakes than cats consuming the 0.6% phosphoric acid-containing diet. There were no differences (P > 0.05) in urine pH and specific gravity between cats fed the different acidifier types. Cats consuming the 0.6% phosphoric acid-containing diet tended (P = 0.07) to have a higher urine pH 8 h post-feeding than cats consuming the 0.4 and 0.8% phosphoric acid-containing diets. Urine pH was highest at 4 h post-feeding except for cats fed the 0.4% sodium bisulphate- and the 0.6% phosphoric acid-containing diets. No differences (P > 0.05) between acidifiers were found in faecal score or in faecal dry matter and organic matter concentrations. A quadratic response was detected in faecal score for cats consuming the phosphoric acid-containing diets. Cats consuming the 0.6% phosphoric acid diet tended (P = 0.06) to have a lower faecal score than cats consuming the 0.4 and 0.8% phosphoric acid diets. For faecal dry matter, a linear trend was detected in cats consuming the sodium

  16. Dog rose (Rosa canina L.) as a functional ingredient in porcine frankfurters without added sodium ascorbate and sodium nitrite.

    PubMed

    Vossen, Els; Utrera, Mariana; De Smet, Stefaan; Morcuende, David; Estévez, Mario

    2012-12-01

    The effect of dog rose (Rosa canina L.; RC), rich in polyphenols and ascorbic acid, on lipid and protein oxidation, colour stability and texture of frankfurters was investigated. Four treatments were prepared: with 5 or 30 g/kg RC extract and without sodium ascorbate and sodium nitrite (5RC and 30RC, respectively), a positive control (with sodium ascorbate and sodium nitrite; PC) and a negative control (without sodium ascorbate, sodium nitrite or RC extract; NC). Hexanal values were much higher throughout storage in NC compared to RC and PC frankfurters (P<0.001). The RC extracts protected against protein oxidation, but not as efficiently as PC (P<0.05). In the RC treated frankfurters, lower a* values were measured compared to PC due to the lack of sodium nitrite. In conclusion, dog rose can act as a natural antioxidant in frankfurters, but not as full replacer for sodium nitrite.

  17. Fundamental spectra of optical functions of ferroelectric sodium nitrite

    SciTech Connect

    Sobolev, V. V. Kalugin, A. I.; Sobolev, V. Val.; Iskhakova, S. G.

    2008-07-15

    Spectra of optical fundamental functions of ferroelectric sodium nitrite were determined in the range 4-24 eV at 77 K for the three polarizations: E -parallel a, E -parallel b, and E -parallel c. The calculations were based on the experimental R(E) reflection spectra and integral Kramers-Kronig relations. Using the method of Argand diagrams, the permittivity and bulk characteristic electron loss spectra were decomposed into the elementary transverse and longitudinal components. Their main parameters were determined. The obtained data were compared with the theoretical calculations of the permittivity spectra performed using the FPLAPW method. The main features of the permittivity spectra, the parameters of the transitions, and their theoretical nature were established.

  18. 78 FR 68474 - Sodium Nitrite From China And Germany; Scheduling of Expedited Five-Year Reviews Concerning the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... COMMISSION Sodium Nitrite From China And Germany; Scheduling of Expedited Five-Year Reviews Concerning the Countervailing Duty Order and Antidumping Duty Order on Sodium Nitrite From China and the Antidumping Duty Order on Sodium Nitrite From Germany AGENCY: United States International Trade Commission. ACTION:...

  19. 78 FR 69646 - Sodium Nitrite From the People's Republic of China: Final Results of the Expedited First Sunset...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-20

    ... International Trade Administration Sodium Nitrite From the People's Republic of China: Final Results of the... countervailing duty (``CVD'') order on sodium nitrite from the People's Republic of China (``PRC'') would be... sodium nitrite from the PRC, pursuant to section 751(c) of the Tariff Act of 1930, as amended (``the...

  20. Acute cyanide intoxication treated with a combination of hydroxycobalamin, sodium nitrite, and sodium thiosulfate.

    PubMed

    Mannaioni, Guido; Vannacci, Alfredo; Marzocca, Cosimo; Zorn, Anna Monica; Peruzzi, Sandro; Moroni, Flavio

    2002-01-01

    An 80-year-old diabetic patient was admitted to the hospital because of sudden unconsciousness and severe metabolic acidosis. His son reported the possibility of cyanide poisoning. Clinical data and the detection of cyanide in blood and gastric material confirmed this possibility. Supportive therapy and the following antidotes--sodium nitrite two doses 300 mg i.v., sodium thiosulfate 3 g i.v., and hydroxocobalamin 4 g in 24 hours--were administered immediately and the patient completely recovered in 48 hours. Our observations suggest that timely and appropriate use of antidotes for cyanide intoxication may prevent death, even in aged diabetic patients.

  1. Thymoquinone ameliorates testicular tissue inflammation induced by chronic administration of oral sodium nitrite.

    PubMed

    Alyoussef, A; Al-Gayyar, M M H

    2016-06-01

    Although sodium nitrite has been widely used as food preservative, building bases of scientific evidence about nitrite continues to oppose the general safety in human health. Moreover, thymoquinone (TQ) has therapeutic potential as antioxidant, anti-inflammatory, antibacterial and anticancer. Therefore, we investigated the effects of both sodium nitrite and TQ on testicular tissues of rats. Forty adult male Sprague Dawley rats were used. They received either 80 mg kg(-1) sodium nitrite or 50 mg kg(-1) TQ daily for twelve weeks. Serum testosterone was measured. Testis were weighed and the testicular tissue homogenates were used for measurements of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-4, IL-6, IL10, caspase-3, caspase-8 and caspase-9. Sodium nitrite resulted in significant reduction in serum testosterone concentration and elevation in testis weight and Gonado-Somatic Index. We found significant reduction in testicular tissues levels of IL-4 and IL-10 associated with elevated levels of TNF-α, IL-1β, IL-6, caspase-3, caspase-8 and caspase-9. In conclusion, chronic oral sodium nitrite induced changes in the weight of rat testis accompanied by elevation in the testicular tissue level of oxidative stress markers and inflammatory cytokines. TQ attenuated sodium nitrite-induced testicular tissue damage through blocking oxidative stress, restoration of normal inflammatory cytokines balance and blocking of apoptosis.

  2. Sodium nitrite blocks the activity of aminoglycosides against Pseudomonas aeruginosa biofilms.

    PubMed

    Zemke, Anna C; Gladwin, Mark T; Bomberger, Jennifer M

    2015-01-01

    Sodium nitrite has broad antimicrobial activity at pH 6.5, including the ability to prevent biofilm growth by Pseudomonas aeruginosa on the surfaces of airway epithelial cells. Because of its antimicrobial activity, nitrite is being investigated as an inhaled agent for chronic P. aeruginosa airway infections in cystic fibrosis patients. However, the interaction between nitrite and commonly used aminoglycosides is unknown. This paper investigates the interaction between nitrite and tobramycin in liquid culture, abiotic biofilms, and a biotic biofilm model simulating the conditions in the cystic fibrosis airway. The addition of nitrite prevented killing by aminoglycosides in liquid culture, with dose dependence between 1.5 and 15 mM. The effect was not blocked by the nitric oxide scavenger CPTIO or dependent on efflux pump activity. Nitrite shifted the biofilm minimal bactericidal concentration (MBC-biofilm) from 256 μg/ml to >1,024 μg/ml in an abiotic biofilm model. In a biotic biofilm model, the addition of 50 mM nitrite decreased the antibiofilm activity of tobramycin by up to 1.2 log. Respiratory chain inhibition recapitulated the inhibition of aminoglycoside activity by nitrite, suggesting a potential mechanism of inhibition of energy-dependent aminoglycoside uptake. In summary, sodium nitrite induces resistance to both gentamicin and tobramycin in P. aeruginosa grown in liquid culture, as an abiotic biofilm, or as a biotic biofilm.

  3. Evaluation of sodium nitrite addition with tank 241-AY-102 waste

    SciTech Connect

    LECHELT, J.A.

    2001-10-30

    Analyses of waste samples taken from tank 241-AY-102 indicate the tank interstitial liquid is deficient in nitrite in accordance with corrosion prevention chemistry. The supernatant was within specifications. Corrosion control is a Technical Safety Requirement (TSR) level control implemented in HNF-IP-I266 (CHG 2001 b), Administrative Control (AC) 5. IS, ''Chemistry Control Program.'' Sodium hydroxide (caustic) solution was added to the tank in early 2001 to bring it into specification for hydroxide. Sodium nitrite solution will be added to the tank to bring the interstitial liquid into specification for nitrite.

  4. Single-Dose Pharmacokinetics of Different Oral Sodium Nitrite Formulations in Diabetes Patients

    PubMed Central

    Predmore, Benjamin L.; Flanagan, Douglas R.; Giordano, Tony; Qiu, Yang; Brandon, Angela; Lefer, David J.; Patel, Rakesh P.; Kevil, Christopher G.

    2012-01-01

    Abstract Background Diabetic foot ulcers, although associated with macrovascular disease and neuropathy, have a microvascular disease causing ischemia not amenable to surgical intervention. Nitrite selectively releases nitric oxide in ischemic tissues, and diabetes subjects have low nitrite levels that do not increase with exercise. This study explores the safety and pharmacokinetics of a single dose of sodium nitrite in subjects with diabetic foot ulcers. Subjects and Methods Using a blinded, randomized crossover study design, 12 subjects with diabetes mellitus and active or healed foot ulcers received a single dose of sodium nitrite on two occasions 7–28 days apart, once with an immediate release (IR) formulation and once with an enteric-coated (EC) formulation for delayed release. Serum nitrite, nitrate, methemoglobin, sulfhemoglobin, blood pressure, pulse rate, complete blood count, chemistry panel, electrocardiogram, and adverse events were followed for up to 6 h after each dose. The IR and EC nitrite levels were analyzed by one-way analysis of variance and by pharmacokinetic modeling. Results The IR formulation elevated nitrite levels between 0.25 and 0.75 h (P<0.05). The EC formulation did not elevate nitrite levels significantly, but both formulations gave plasma nitrite levels previously suggested to be therapeutic (approximately 2–5 μM). The IR formulation gave an asymptomatic blood pressure drop of 10/6 mm Hg (P<0.003), and two subjects experienced mild flushing. There was no elevation of methemoglobin or other safety concerns. Pharmacokinetic modeling of plama nitrite levels gave r2 values of 0.81 and 0.97 for the fits for IR and EC formulations, respectively. Conclusions Oral sodium nitrite administration is well tolerated in diabetes patients. PMID:22468627

  5. Nitrite

    Integrated Risk Information System (IRIS)

    Nitrite ; CASRN 14797 - 65 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  6. Consistent antioxidant and antihypertensive effects of oral sodium nitrite in DOCA-salt hypertension.

    PubMed

    Amaral, Jefferson H; Ferreira, Graziele C; Pinheiro, Lucas C; Montenegro, Marcelo F; Tanus-Santos, Jose E

    2015-08-01

    Hypertension is a common disease that includes oxidative stress as a major feature, and oxidative stress impairs physiological nitric oxide (NO) activity promoting cardiovascular pathophysiological mechanisms. While inorganic nitrite and nitrate are now recognized as relevant sources of NO after their bioactivation by enzymatic and non-enzymatic pathways, thus lowering blood pressure, mounting evidence suggests that sodium nitrite also exerts antioxidant effects. Here we show for the first time that sodium nitrite exerts consistent systemic and vascular antioxidant and antihypertensive effects in the deoxycorticosterone-salt (DOCA-salt) hypertension model. This is particularly important because increased oxidative stress plays a major role in the DOCA-salt hypertension model, which is less dependent on activation of the renin-angiotensin system than other hypertension models. Indeed, antihypertensive effects of oral nitrite were associated with increased plasma nitrite and nitrate concentrations, and completely blunted hypertension-induced increases in plasma 8-isoprostane and lipid peroxide levels, in vascular reactive oxygen species, in vascular NADPH oxidase activity, and in vascular xanthine oxidoreductase activity. Together, these findings provide evidence that the oral administration of sodium nitrite consistently decreases the blood pressure in association with major antioxidant effects in experimental hypertension.

  7. [Sodium nitrite enhanced the potentials of migration and invasion of human hepatocellular carcinoma SMMC-7721 cells through induction of mitophagy].

    PubMed

    Gui, Guan; Meng, Shan-shan; Li, Lu-juan; Liu, Bin; Liang, Hong-xia; Huangfu, Chao-shen

    2016-01-01

    Nitrites play multiple characteristic functions in invasion and metastasis of hepatic cancer cells, but the exact mechanism is not yet known. Cancer cells can maintain the malignant characteristics via clearance of excess mitochondria by mitophagy. The purpose of this article was to determine the roles of nitrite, reactive oxygen species (ROS) and hypoxia inducing factor 1 alpha (HIF-1 α) in mitophagy of hepatic cancer cells. After exposure of human hepatocellular carcinoma SMMC-7721 cells to a serial concentrations of sodium nitrite for 24 h under normal oxygen, the maximal cell vitality was increased by 16 mg x (-1) sodium nitrite. In addition, the potentials of migration and invasion for SMMC-7721 cells were increased significantly at the same time. Furthermore, sodium nitrite exposure displayed an increase of stress fibers, lamellipodum and perinuclear mitochondrial distribution by cell staining with Actin-Tracker Green and Mito-Tracker Red, which was reversed by N-acetylcysteine (NAC, a reactive oxygen scavenger). DCFH-DA staining with fluorescent microscopy showed that the intracellular level of ROS concentration was increased by the sodium nitrite treatment. LC3 immunostaining and Western blot results showed that sodium nitrite enhanced cell autophagy flux. Under the transmission electron microscopy (TEM), more autolysosomes formed after sodium nitrite treatment and NAC could prevent autophagosome degradation. RT-PCR results indicated that the expression levels of COX I and COXIV mRNA were decreased significantly after sodium nitrite treatment. Meanwhile, laser scanning confocal microscopy showed that sodium nitrite significantly reduced mitochondrial mass detected by Mito-Tracker Green staining. The expression levels of HIF-1α, Beclin-1 and Bnip3 (mitophagy marker molecular) increased remarkably after sodium nitrite treatment, which were reversed by NAC. Our results demonstrated that sodium nitrite (16 mg x L(-1)) increased the potentials of invasion and

  8. Calorimetry of matrix-isolated sodium nitrite NaNO2

    NASA Astrophysics Data System (ADS)

    Egorov, V. M.; Markov, Yu. F.; Roginskii, E. M.; Stukova, E. V.

    2016-11-01

    Differential scanning calorimetry has been used to carry out a high-precision study of sodium nitrite NaNO2 incorporated into different silicate nanoporous matrices. Heat-capacity maxima due to smeared ferroelectric phase transitions have been discovered. Characteristics (intensity, half-width, phase-transition temperature, etc.) of the maxima have been investigated. Heat-capacity maxima related to an incommensurable phase transition have been reliably identified. The maxima can be attributed to the formation of appropriate orientation of sodium-nitrite nanocrystals in matrix pores.

  9. 78 FR 69368 - Sodium Nitrite From Germany and the People's Republic of China: Final Results of the Expedited...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-19

    ... International Trade Administration Sodium Nitrite From Germany and the People's Republic of China: Final Results... reviews of the antidumping duty (``AD'') orders on sodium nitrite from Germany and the People's Republic.... SUPPLEMENTARY INFORMATION: Background On August 27, 2008, the Department published the AD orders on...

  10. 21 CFR 172.177 - Sodium nitrite used in processing smoked chub.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... The food additive sodium nitrite may be safely used in combination with salt (NaCl) to aid in... has a salt (NaCl) content of not less than 3.5 percent, as measured in the loin muscle, and the...

  11. A Putative ABC Transporter Permease Is Necessary for Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa under Aerobic and Anaerobic Planktonic and Biofilm Conditions

    PubMed Central

    McDaniel, Cameron; Su, Shengchang; Panmanee, Warunya; Lau, Gee W.; Browne, Tristan; Cox, Kevin; Paul, Andrew T.; Ko, Seung-Hyun B.; Mortensen, Joel E.; Lam, Joseph S.; Muruve, Daniel A.; Hassett, Daniel J.

    2016-01-01

    Pseudomonas aeruginosa (PA) is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite (A-NO2−, pH 6.5) at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to A-NO2−. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to A-NO2−, but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin, and chloramphenicol, respectively. Treatment of bacteria with A-NO2− plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 10 mM A-NO2−, and EDTA (1 mM, aerobic, anaerobic). Most importantly, the PA4455 mutant was also sensitive to A-NO2− in biofilms. A-NO2− sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM) that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, A-NO2− as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains. PMID:27064218

  12. The effect of sucrose on unfrozen water and syneresis of acidified sodium caseinate-xanthan gels.

    PubMed

    Braga, A L M; Cunha, R L

    2005-07-01

    The influence of the ingredients of acidified Na caseinate-xanthan-sucrose gels on thermophysical properties and syneresis of the gels was studied. Sucrose concentration affected all of the gel equilibrium properties and the rate of syneresis. The positive effect of sucrose on syneresis and unfrozen water (UFW) values was attributed to different effects. The amount of UFW was governed mainly by the colligative properties of sucrose whereas the equilibrium syneresis behaviour was associated with the changes in network dynamics caused by the kosmotropic properties of sucrose. The latter could enhance xanthan-sucrose association or favour xanthan-protein interactions.

  13. Refining the Use of Sodium Azide to Counteract Nitrite Interference in Dissolved Oxygen Analysis of Seawater

    NASA Astrophysics Data System (ADS)

    Miller, M. T.

    2014-12-01

    High nitrite concentrations are known to interfere with the analysis of dissolved oxygen in seawater samples, though the affected range has yet to be defined. This error can be counteracted by the addition of sodium azide to the hydroxide-iodide pickling reagent. The 2013 US GEOTRACES zonal transect included stations off the coast of Peru with nitrite values up to 10μmol/kg in the upper 400 meters of the water column. Low concentrations of dissolved oxygen were also present in the upper 800 meters, providing an opportunity to study the effect of high nitrite levels on dissolved oxygen analysis over a range of concentrations. Without the addition of azide, the error in dissolved oxygen measurement increased linearly with nitrite concentration. The interference was only significant in samples with nitrite concentrations higher than 1.5 μmol/kg, all of which also had low dissolved oxygen concentrations (<45μmol/kg). The unique combination of high nitrite and low dissolved oxygen is present in such well known and relatively small areas of the world's oceans that the addition of azide is not necessary as a standard procedure for the vast majority of oceanographic measurements.

  14. Corrosion Fatigue Behavior of 316LN SS in Acidified Sodium Chloride Solution at Applied Potential

    NASA Astrophysics Data System (ADS)

    Poonguzhali, A.; Pujar, M. G.; Mallika, C.; Mudali, U. Kamachi

    2015-05-01

    The influence of acidified 1 M NaCl solution by addition of 2 ml/L of HCl on the cyclic plastic deformation of AISI Type 316LN SS containing 0.07 wt.% and 0.22 wt.% N was investigated as a function of the applied potentials. The corrosion fatigue (CF) behavior of stainless steel (SS) was explained vis-a-vis the dislocation behavior, the propensity to form microcracks, and the evolution of the current transients based on the studies carried out at both room-temperature and boiling conditions. CF experiments were conducted using round tensile specimens at a stress ratio of 0.5 and a frequency of 0.1 Hz. Two different kinds of damage mechanisms were observed (I) the damage mechanism in the stable-passive state was correlated with the localization of the anodic dissolution due to a depassivation-repassivation process, whereas (II) the cyclic stress induced pitting corrosion in the metastable pitting state, which resulted in formation of microcracks. The study of the microcracking process and its evolution is a key to the physical mechanism by which the fatigue life of stainless steels would be affected in an aqueous corrosive solution under the applied potential.

  15. Electroencephalographic Response to Sodium Nitrite May Predict Delayed Cerebral Ischemia After Severe Subarachnoid Hemorrhage

    PubMed Central

    Rowland, Matthew J.; Ezra, Martyn; Herigstad, Mari; Hayen, Anja; Sleigh, Jamie W.; Westbrook, Jon; Warnaby, Catherine E.; Pattinson, Kyle T. S.

    2016-01-01

    Objectives: Aneurysmal subarachnoid hemorrhage often leads to death and poor clinical outcome. Injury occurring during the first 72 hours is termed “early brain injury,” with disruption of the nitric oxide pathway playing an important pathophysiologic role in its development. Quantitative electroencephalographic variables, such as α/δ frequency ratio, are surrogate markers of cerebral ischemia. This study assessed the quantitative electroencephalographic response to a cerebral nitric oxide donor (intravenous sodium nitrite) to explore whether this correlates with the eventual development of delayed cerebral ischemia. Design: Unblinded pilot study testing response to drug intervention. Setting: Neuroscience ICU, John Radcliffe Hospital, Oxford, United Kingdom. Patients: Fourteen World Federation of Neurosurgeons grades 3, 4, and 5 patients (mean age, 52.8 yr [range, 41–69 yr]; 11 women). Interventions: IV sodium nitrite (10 μg/kg/min) for 1 hour. Measurements and Main Results: Continuous electroencephalographic recording for 2 hours. The alpha/delta frequency ratio was measured before and during IV sodium nitrite infusion. Seven of 14 patients developed delayed cerebral ischemia. There was a +30% to +118% (range) increase in the alpha/delta frequency ratio in patients who did not develop delayed cerebral ischemia (p < 0.0001) but an overall decrease in the alpha/delta frequency ratio in those patients who did develop delayed cerebral ischemia (range, +11% to –31%) (p = 0.006, multivariate analysis accounting for major confounds). Conclusions: Administration of sodium nitrite after severe subarachnoid hemorrhage differentially influences quantitative electroencephalographic variables depending on the patient’s susceptibility to development of delayed cerebral ischemia. With further validation in a larger sample size, this response may be developed as a tool for risk stratification after aneurysmal subarachnoid hemorrhage. PMID:27441898

  16. Thymoquinone ameliorated elevated inflammatory cytokines in testicular tissue and sex hormones imbalance induced by oral chronic toxicity with sodium nitrite.

    PubMed

    Alyoussef, Abdullah; Al-Gayyar, Mohammed M H

    2016-07-01

    Scientific evidence illustrated the health hazards of exposure to nitrites for prolonged time. Nitrites affected several body organs due to oxidative, inflammatory and apoptosis properties. Furthermore, thymoquinone (TQ) had curative effects against many diseases. We tried to discover the impact of both sodium nitrite and TQ on inflammatory cytokines contents in testicular tissues and hormonal balance both in vivo and in vitro. Fifty adult male SD rats received 80mg/kg sodium nitrite and treated with either 25 or 50mg/kg TQ daily by oral-gavage for twelve weeks. Testis were removed for sperms' count. Testicular tissue homogenates were used for assessment of protein and gene expression of IL-1β, IL-6, TNF-α, Nrf2 and caspase-3. Serum samples were used for measurement of testosterone, LH, FSH and prolactin. Moreover, all the parameters were measured in human normal testis cell-lines, CRL-7002. Sodium nitrite produced significant decrease in serum testosterone associated with raised FSH, LH and prolactin. Moreover, sodium nitrite significantly elevated TNF-α, IL-1β, IL-6, caspase-3 and reduced Nrf2. TQ significantly reversed all these effects both in vivo and in vitro. In conclusion, TQ ameliorated testicular tissue inflammation and restored the normal balance of sex hormones induced by sodium nitrite both in vivo and in vitro.

  17. Short communication: Use of a mixture of sodium nitrite, sodium benzoate, and potassium sorbate in aerobically challenged silages.

    PubMed

    Knicky, Martin; Spörndly, Rolf

    2015-08-01

    Aerobic instability is still a common problem with many types of silages, particularly well-fermented silages. This study evaluated the effect of adding an additive mixture based on sodium nitrite, sodium benzoate, and potassium sorbate to a variety of crop materials on fermentation quality and aerobic stability of silages. Ensiling conditions were challenged by using a low packing density (104±4.3kg of dry matter/m(3)) of forage and allowing air ingression into silos (at 14 and 7 d before the end of the storage, for 8 h per event). Additive-treated silages were found to have significantly lower pH and reduced formation of ammonia-N, 2.3-butanediol, and ethanol compared with untreated control silages. Yeast growth was significantly reduced by additive treatment in comparison with untreated control silage. Consequently, additive-treated silages were considerably more aerobically stable (6.7 d) than untreated control silages (0.5 d). Overall, adding 5mL/kg of fresh crop of the additive based on sodium nitrite, sodium benzoate, and potassium sorbate reduced undesirable microorganisms in silages and thereby provided suitable ensiling conditions and prolonged aerobic stability, even under air-challenged laboratory ensiling conditions.

  18. Is there a role of inducible nitric oxide synthase activation in the delayed antiarrhythmic effect of sodium nitrite?

    PubMed

    Demeter-Haludka, Vivien; Juhász, László; Kovác, Mária; Gardi, János; Végh, Ágnes

    2017-04-01

    This study aimed to examine whether inducible nitric oxide synthase (iNOS) plays a role in the delayed antiarrhythmic effect of sodium nitrite. Twenty-one dogs were infused intravenously with sodium nitrite (0.2 μmol·kg(-1)·min(-1)) for 20 min, either in the absence (n = 12) or in the presence of the iNOS inhibitor S-(2-aminoethyl)-isothiourea (AEST) (total dose 2.0 mg·kg(-1) i.v., n = 9). Control dogs (n = 12) were given saline. Twenty-four hours later, all of the dogs were subjected to a 25 min period occlusion of the left anterior descending coronary artery followed by rapid reperfusion. Dogs treated with AEST and nitrite received again AEST prior to the occlusion. Compared with the controls, sodium nitrite markedly reduced the number of ectopic beats, the number and incidence of ventricular tachycardia, and the incidence of ventricular fibrillation during occlusion and increased survival (0% versus 50%) from the combined ischaemia and reperfusion insult. Although AEST completely inhibited iNOS activity, the nitrite-induced increase in NO bioavailability during occlusion was not substantially modified. Furthermore, AEST attenuated but did not completely abolish the antiarrhythmic effect of nitrite. The marked delayed antiarrhythmic effect of sodium nitrite is not entirely due to the activation of iNOS; other mechanisms may certainly play a role.

  19. Temperature dependent structural and spectroscopic studies of sodium gallosilicate nitrite sodalite

    SciTech Connect

    Gesing, Thorsten M.; Schmidt, Burkhard C.; Murshed, M. Mangir

    2010-11-15

    We report on temperature dependent crystal structures of sodium gallosilicate nitrite sodalite Na{sub 8}[GaSiO{sub 4}]{sub 6}(NO{sub 2}){sub 2} between 293 and 973 K. The crystal structures were refined from X-ray powder data Rietveld refinements in the space group P4-bar 3n. The gallium and silicon atoms on the tetrahedral framework positions are totally ordered. The nitrite anion was found slightly away from the center of the sodalite cage, which is tetrahedrally surrounded by four sodium atoms. The linear thermal expansion coefficient was calculated from the lattice expansion data. The change of the geometries of the framework has been observed on heating the polycrystalline sample, that is, T-O bond lengths slightly decreased, T-O-T angle non-linearly increased, tilt of the TO{sub 4} tetrahedra decreased (framework untwist) and their tetragonal tetrahedral distortion decreased with some scatterings. Of particular note, the tetragonal tetrahedra distortion of GaO{sub 4} tetrahedra approached close to zero at higher temperatures, which points to a distortion direction to a relaxed state of GaO{sub 4} tetrahedra on heating. The mobility of sodium atoms above 600 K leads to different sodium content in some sodalite cages and results in the appearance of different domains. The consequence of this domain formation to the strain of the crystalline system and to the average crystals size have been explained. Both Fourier transform infrared and micro-Raman spectra showed typical absorption bands of nitrite sodalite. The change of the frequency shift and full-width at half-maximum of some selected bands has been studied as function of temperature.

  20. Effects of water, sodium hypochlorite, peroxyacetic acid, and acidified sodium chlorite on in-shell hazelnuts inoculated with Salmonella enterica serovar Panama.

    PubMed

    Weller, Lisa D; Daeschel, Mark A; Durham, Catherine A; Morrissey, Michael T

    2013-12-01

    Recent foodborne disease outbreaks involving minimally processed tree nuts have generated a need for improved sanitation procedures. Chemical sprays and dips have shown promise for reducing pathogens on fresh produce, but little research has been conducted for in-shell hazelnuts. This study analyzed the effectiveness of 3 chemical sanitizers for reducing Salmonella on in-shell hazelnuts. Treatments of water, sodium hypochlorite (NaOCl; 25 and 50 ppm), peroxyacetic acid (PAA; 80 and 120 ppm), and acidified sodium chlorite (ASC; 450, 830, and 1013 ppm) were sprayed onto hazelnut samples inoculated with Salmonella enterica serovar Panama. Hazelnut samples were immersed in liquid cultures of S. Panama for 24 h, air-dried, and then sprayed with water and chemical treatments. Inoculation achieved S. Panama populations of approximately 8.04 log CFU/hazelnut. Surviving S. panama populations were evaluated using a nonselective medium (tryptic soy agar), incubated 3 h, and then overlaid with selective media (xylose lysine deoxycholate agar). All of the chemical treatments significantly reduced S. Panama populations (P ≤ 0.0001). The most effective concentrations of ASC, PAA, and NaOCl treatments reduced populations by 2.65, 1.46, and 0.66 log units, respectively. ASC showed the greatest potential for use as a postharvest sanitation treatment.

  1. Effects of potassium lactate, sodium metasilicate, peroxyacetic acid, and acidified sodium chlorite on physical, chemical, and sensory properties of ground beef patties.

    PubMed

    Quilo, S A; Pohlman, F W; Brown, A H; Crandall, P G; Dias-Morse, P N; Baublits, R T; Aparicio, J L

    2009-05-01

    Beef trimmings were treated with 3% potassium lactate (KL), 4% sodium metasilicate (NMS), 0.02% peroxyacetic acid (PAA) or 0.1% acidified sodium chlorite (ASC) or left untreated (CON). Beef trimmings were ground, pattied, and sampled for 7 days. Under simulated retail display, instrumental color, sensory characteristics, TBARS, pH, and Lee-Kramer shear force were measured to evaluate the impact of the treatments on the quality attributes. The NMS and PAA patties were redder (a(∗), P<0.05) than CON on days 0-3. Panelists found KL, NMS, PAA, and ASC patties to have less (P<0.05) or similar (P>0.05) off odor to CON on days 0-3. The NMS and PAA treated patties had lower (P<0.05) lipid oxidation than the CON at days 0, 3, and 7. Therefore, KL, NMS, PAA, and ASC treatments on beef trimmings can potentially improve or maintain quality attributes of beef patties.

  2. Effectiveness of acidified sodium chlorite and other sanitizers to control Escherichia coli O157:H7 on tomato surfaces.

    PubMed

    Inatsu, Yasuhiro; Kitagawa, Tomoko; Bari, Md Latiful; Nei, Daisuke; Juneja, Vijay; Kawamoto, Shinichi

    2010-06-01

    The use of a suitable sanitizer can reduce the risk of produce-related foodborne illnesses. We evaluated the effectiveness of several sanitizers to reduce inoculated Escherichia coli O157:H7 on the surface of cherry tomatoes (Solanum lycopersicum var. cerasiform). Depending on the method of inoculation (dipping/spotting), each of 80 g (eight tomatoes) of inoculated cherry tomatoes was washed in 400 mL of sanitizer solutions or 400 mL distilled water for 5 minutes. The effectiveness of sanitizers on spot-inoculated E. coli O157:H7 on tomato surfaces was found higher than on dip-inoculated tomatoes. Washing with water or chlorine water (0.1 g/L as free chlorine) could reduce 1.3 log CFU/g of E. coli O157:H7 in dip-inoculated (6.8 log CFU/g) tomatoes. Washing with lactic acid (LA) solution (1.0 g/L), phytic acid solution (1.0 g/L), calcinated seashells (oyster/sakhalin surf clam), and 1.0 g/L chitosan in 0.5 g/L LA (Chito) did not exhibit a significant higher effectiveness than that of water wash alone (1.0 log CFU/g). Acidified sodium chlorite (ASC) solution prepared from 0.5 g/L of sodium chlorite and 1.0 g/L LA or phytic acid reduced 3.5 log CFU/g of E. coli O157:H7 in dip-inoculated tomato surfaces. ASC (0.5 g/L of sodium chlorite and 1.0 g/L of LA) wash followed by a second wash with LA exhibited an additional sanitary effectiveness compared to a single wash with ASC. However, washing with ASC followed by a second wash with Chito exhibited an additional 1.0 log CFU/g reduction compared to a secondary wash with water. No significant difference of color, taste, and texture was observed among the washed cherry tomatoes.

  3. Effects of sodium nitrite supplementation on vascular function and related small metabolite signatures in middle-aged and older adults

    PubMed Central

    Johnson, Lawrence C.; Brooks, Forrest A.; Evans, Trent D.; Justice, Jamie N.; Cruickshank-Quinn, Charmion; Reisdorph, Nichole; Bryan, Nathan S.; McQueen, Matthew B.; Santos-Parker, Jessica R.; Chonchol, Michel B.; Bassett, Candace J.; Sindler, Amy L.; Giordano, Tony; Seals, Douglas R.

    2015-01-01

    Insufficient nitric oxide (NO) bioavailability plays an important role in endothelial dysfunction and arterial stiffening with aging. Supplementation with sodium nitrite, a precursor of NO, ameliorates age-related vascular endothelial dysfunction and arterial stiffness in mice, but effects on humans, including the metabolic pathways altered, are unknown. The purpose of this study was to determine the safety, feasibility, and efficacy of oral sodium nitrite supplementation for improving vascular function in middle-aged and older adults and to identify related circulating metabolites. Ten weeks of sodium nitrite (80 or 160 mg/day, capsules, TheraVasc; randomized, placebo control, double blind) increased plasma nitrite acutely (5- to 15-fold, P < 0.001 vs. placebo) and chronically (P < 0.10) and was well tolerated without symptomatic hypotension or clinically relevant elevations in blood methemoglobin. Endothelial function, measured by brachial artery flow-mediated dilation, increased 45-60% vs. baseline (P < 0.10) without changes in body mass or blood lipids. Measures of carotid artery elasticity (ultrasound and applanation tonometry) improved (decreased β-stiffness index, increased cross-sectional compliance, P < 0.05) without changes in brachial or carotid artery blood pressure. Aortic pulse wave velocity was unchanged. Nitrite-induced changes in vascular measures were significantly related to 11 plasma metabolites identified by untargeted analysis. Baseline abundance of multiple metabolites, including glycerophospholipids and fatty acyls, predicted vascular changes with nitrite. This study provides evidence that sodium nitrite supplementation is well tolerated, increases plasma nitrite concentrations, improves endothelial function, and lessens carotid artery stiffening in middle-aged and older adults, perhaps by altering multiple metabolic pathways, thereby warranting a larger clinical trial. PMID:26607249

  4. Suggestive evidence for the induction of colonic aberrant crypts in mice fed sodium nitrite.

    PubMed

    Zhou, Lin; Zahid, Muhammad; Anwar, Muhammad M; Pennington, Karen L; Cohen, Samuel M; Wisecarver, James L; Shostrom, Valerie; Mirvish, Sidney S

    2016-01-01

    A reported linkage between processed (nitrite-treated) meat products and the incidence of colon cancer could be due to sodium nitrite (NaNO2) itself or to N-nitroso compounds produced from the nitrite. Exposure to nitrite occurs due to residual nitrite in processed meat and to salivary nitrite arising by reduction of nitrate in vegetables and drinking water. Here we tested whether NaNO2 could induce colonic aberrant crypts (ABC) or ABC foci (ACF), which are putative precursors of colon cancer. We fed NaNO2 in drinking water for 20-25 wk to groups of 8-20 adult female mice. After sacrifice, ABC and ACF were counted in 2-cm distal colonic segments. In Experiment 1, no significant differences in ABC/ACF induction were seen between groups of 13-14 A/J mice fed 0, 0.5, or 1.0 g NaNO2/l drinking water. NaNO2 also did not affect fasting blood glucose levels. In Experiment 2, we fed 0, 1.0, 1.25, or 1.5 g NaNO2/l water to groups of 15 CF-1 mice. Five of the mice fed 1.5 g NaNO2/l showed ABC, whereas all other groups showed only 0-2 ABC/group, including 0 ABC for the group fed 1.25 g NaNO2/l. Overall statistical analysis indicated a dose-response p trends of 0.04. Pairwise comparison of ABC between groups fed 1.25 and 1.5 g NaNO2/l showed p 0.02 for both ABC and ACF, but a similar comparison between the untreated and 1.5 g/l groups showed no significant effects. In Experiment 3, hot dogs (18% of diet), which were fed to CF-1 mice previously treated with azoxymethane, inhibited ABC and ACF induction, but this effect was not significant (P = 0.10-0.12). In conclusion, these results support the view that NaNO2 may be a risk factor for colon carcinogenesis.

  5. Decreased dosage of acidified sodium chlorite reduces microbial contamination and maintains organoleptic qualities of ground beef products.

    PubMed

    Bosilevac, Joseph M; Shackelford, Steven D; Fahle, Rick; Biela, Timothy; Koohmaraie, Mohammad

    2004-10-01

    Acidified sodium chlorite (ASC) spray was evaluated at decreased dosages and application rates to determine its efficacy for reducing bacterial contamination on boneless beef trimmings used for production of raw ground beef products while maintaining desirable consumer qualities in the finished ground beef products. Two different applications of ASC (600 ppm applied at a rate of 1.3 oz/lb and 300 ppm applied at a rate of 1 oz/lb) were used to treat boneless beef trimmings before grinding. The effect of ASC treatment on 50/50 lean beef trimmings was greater than on 90/10 trimmings. ASC at 600 ppm reduced both the aerobic plate counts (APC) and Enterobacteriaceae counts (EBC) by 2.3 log CFU/g on 50/50 trimmings, whereas treatment with 300 ppm ASC reduced APC and EBC of 50/50 trimmings by 1.1 and 0.7 log CFU/g, respectively. Ground beef formulations of 90/10 and 73/27 were produced from the treated boneless beef trim and packaged in chubs and in modified atmosphere packaging. The efficacy of ASC spray treatment to inhibit APC and EBC over the shelf life of each ground beef product was monitored. The APC and EBC in ground beef chubs were reduced by 1.0 to 1.5 log CFU/g until day 20. The APC and EBC for products in modified atmosphere packaging were reduced 1.5 to 3.0 log CFU/g throughout their shelf life. Both decreased dosages of ASC were equally effective on 90/10 lean ground beef, but the 300 ppm ASC treatment was slightly better at reducing the EBC of 73/27 ground beef. The organoleptic qualities (color, odor, and taste) of the ground beef products treated with 300 ppm ASC were found to be superior to those treated with 600 ppm ASC. Our results indicated that decreased dosages of ASC reduce contamination and lengthen the shelf life of ground beef. Furthermore, the 300 ppm ASC treatment reduced bacterial counts while maintaining desirable organoleptic ground beef qualities.

  6. Effectiveness of trisodium phosphate, acidified sodium chlorite, citric acid, and peroxyacids against pathogenic bacteria on poultry during refrigerated storage.

    PubMed

    del Río, Elena; Muriente, Rebeca; Prieto, Miguel; Alonso-Calleja, Carlos; Capita, Rosa

    2007-09-01

    The effects of dipping treatments (15 min) in potable water or in solutions (wt/vol) of 12% trisodium phosphate (TSP), 1,200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), and 220 ppm peroxyacids (PA) on inoculated pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Salmonella Enteritidis, Escherichia coli, and Yersinia enterocolitica) and skin pH were investigated throughout storage of chicken legs (days 0, 1, 3, and 5) at 3 +/- 1 degrees C. All chemical solutions reduced microbial populations (P < 0.001) as compared with the control (untreated) samples. Similar bacterial loads (P > 0.05) were observed on water-dipped and control legs. Type of treatment, microbial group, and sampling day influenced microbial counts (P < 0.001). Average reductions with regard to control samples were 0.28 to 2.41 log CFU/g with TSP, 0.33 to 3.15 log CFU/g with ASC, 0.82 to 1.97 log CFU/g with CA, and 0.07 to 0.96 log CFU/g with PA. Average reductions were lower (P < 0.001) for gram-positive (0.96 log CFU/g) than for gram-negative (1.33 log CFU/g) bacteria. CA and ASC were the most effective antimicrobial compounds against gram-positive and gram-negative bacteria, respectively. TSP was the second most effective compound for both bacterial groups. Average microbial reductions per gram of skin were 0.87 log CFU/g with TSP, 0.86 log CFU/g with ASC, 1.39 log CFU/g with CA, and 0.74 log CFU/g with PA for gram-positive bacteria, and 1.28 log CFU/g with TSP, 2.03 log CFU/g with ASC, 1.23 log CFU/g with CA, and 0.78 log CFU/g with PA for gram-negative bacteria. With only a few exceptions, microbial reductions in TSP- and ASC-treated samples decreased and those in samples treated with CA increased throughout storage. Samples treated with TSP and samples dipped in CA and ASC had the highest and lowest pH values, respectively, after treatment. The pH of the treated legs tended to return to normal (6.3 to 6.6) during storage. However, at the end of

  7. Slaughterfloor decontamination of pork carcases with hot water or acidified sodium chlorite - a comparison in two Australian abattoirs.

    PubMed

    Hamilton, D; Holds, G; Lorimer, M; Kiermeier, A; Kidd, C; Slade, J; Pointon, A

    2010-11-01

    A decontamination trial on the effectiveness of hot water or acidified sodium chlorite (SANOVA) treatment on Salmonella spp., Escherichia coli and Total Viable Count (TVC) was undertaken on pork carcases prior to primary chilling in two large pork abattoirs in Australia using belly-strip excision sampling. A total of 123 samples from Abattoir A and 400 samples from Abattoir B were cultured and analysed. Test pigs were selected from herds with a known high level of on-farm Salmonella infection. At Abattoir A, Salmonella spp. were not isolated from carcases. The prevalence of E. coli on control carcases was 92.9% compared with 9.8% for hot water and 12.5% for SANOVA treated carcases. The mean log(10) E. coli concentration for control carcases was 0.89 cfu/gram, compared with -0.83 cfu/gram from hot water and -0.75 cfu/gram from SANOVA treated carcases. The mean log(10) TVC for control carcases was 4.06 compared with 1.81 cfu/gram for hot water and 2.76 cfu/gram for SANOVA treated carcases. At Abattoir B, the prevalence of Salmonella on control carcases was 16% compared with 2.7% for hot water and 7.0% for SANOVA treated carcases. The prevalence of E. coli on control carcases was 69.3% compared with 22% for hot water and 30% for SANOVA treated carcases. The mean log(10) E. coli concentration for control carcases was 0.45 cfu/gram, compared with -0.65 cfu/gram from hot water and -0.60 cfu/gram from SANOVA treated carcases. The mean log(10) TVC for control carcases was 3.00 cfu/gram compared with 2.10 cfu/gram for hot water and 2.53 cfu/gram for SANOVA treated carcases. The reductions in prevalence and mean log(10) concentrations in the present trial were all found to be statistically significant and indicate that carcases decontamination with either hot water or SANOVA are effective risk management options immediately available to the pork industry.

  8. Hemorheological changes and hematometric erythrocyte characteristics in rats after sodium nitrite intoxication

    NASA Astrophysics Data System (ADS)

    Ivanov, Ivan; Gluhcheva, Yordanka; Petrova, Emilia; Antonova, Nadia

    2014-05-01

    Sodium nitrite (NaNO2) is a precursor to a variety of organic compounds (pharmaceuticals, dyes and pesticides), but it is best known as a food additive. The aim of the study is to investigate the influence of acute (i.p.) treatment of Wistar rats with NaNO2 (at the dose of 50 mg/kg b.w.) on the blood rheological properties and erythrocyte hematometric indices (Hb, HCT, RBC, MCV, RDW, MCH, MCHC). The significant differences were not found in the whole blood viscosity (WBV) values of the control and NaNO2-treated groups. The changes in the erythrocyte hematometric indices were statistically significant for RDW, MCHC and MCH at the 1st hour, five- and ten days after NaNO2 administration. Interestingly, at the day 5th of the NaNO2 treatment we obtained statistically significant lower values for the RBC count, Hb, HCT, RDW, as well as elevated indices MCV (no statistically significant), MCH, MCHC. The results obtained indicate that hemorheological and hematometric parameters examined should be monitored in cases of acute exposure to nitrites — for the purposes of clinical toxicology. The quantitative values of hematometric indices reported in our experimental model could be suitable for predicting NaNO2 intoxication and methemoglobinemia in animals and humans.

  9. Toxicity detection of sodium nitrite, borax and aluminum potassium sulfate using electrochemical method.

    PubMed

    Yu, Dengbin; Yong, Daming; Dong, Shaojun

    2013-04-01

    Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an analyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose-glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions (solution pH 7.0, 37 degrees C and reaction for 3 hr). The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be: sodium nitrite > borax > aluminum potassium sulfate > blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives.

  10. EFFECTS OF ADDITION RATE AND ACID MATRIX ON THE DESTRUCTION OF AMMONIUM BY THE SEMI-CONTINUOUS ADDITION OF SODIUM NITRITE DURING EVAPORATION

    SciTech Connect

    Kyser, E

    2007-08-27

    The destruction of ammonium by the semi-continuous addition of sodium nitrite during acidic evaporation can be achieved with a wide range of waste compositions. The efficiency of nitrite utilization for ammonium destruction was observed to vary from less than 20% to 60% depending on operating conditions. The effects of nitric acid concentration and nitrite addition rate are dominant factors that affect the efficiency of nitrite utilization for ammonium destruction. Reducing the acid concentration by performing acid recovery via steam stripping prior to performing nitrite destruction of ammonium will require more nitrite due to the low destruction efficiency. The scale-up of the baseline rate nitrite addition rate from the 100 mL to the 1600 gallon batch size has significant uncertainty and poses the risk of lower efficiency at the plant scale. Experience with plant scale processing will improve confidence in the application of nitrite destruction of ammonium to different waste streams.

  11. Predictive model for growth of Clostridium perfringens during cooling of cooked beef supplemented with NaCl, sodium nitrite and sodium pyrophosphate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper presents a model for predicting relative growth of C. perfringens in ground beef products at different percentages of salt (0%, 1%, 2% and 3%) and nitrite (0 and 200 ppm). Included in the experiments were different levels of sodium pyrophosphate (SPP). The results of the experiments indic...

  12. Effect of Sodium Nitrite on Ischaemia and Reperfusion-Induced Arrhythmias in Anaesthetized Dogs: Is Protein S-Nitrosylation Involved?

    PubMed Central

    Seprényi, György; Kaszaki, József; Murphy, Elizabeth; Végh, Ágnes

    2015-01-01

    Background and Purpose To provide evidence for the protective role of inorganic nitrite against acute ischaemia and reperfusion-induced ventricular arrhythmias in a large animal model. Experimental Approach Dogs, anaesthetized with chloralose and urethane, were administered intravenously with sodium nitrite (0.2 µmolkg-1min-1) in two protocols. In protocol 1 nitrite was infused 10 min prior to and during a 25 min occlusion of the left anterior descending (LAD) coronary artery (NaNO2-PO; n = 14), whereas in protocol 2 the infusion was started 10 min prior to reperfusion of the occluded vessel (NaNO2-PR; n = 12). Control dogs (n = 15) were infused with saline and subjected to the same period of ischaemia and reperfusion. Severities of ischaemia and ventricular arrhythmias, as well as changes in plasma nitrate/nitrite (NOx) levels in the coronary sinus blood, were assessed throughout the experiment. Myocardial superoxide and nitrotyrosine (NT) levels were determined during reperfusion. Changes in protein S-nitrosylation (SNO) and S-glutathionylation were also examined. Key Results Compared with controls, sodium nitrite administered either pre-occlusion or pre-reperfusion markedly suppressed the number and severity of ventricular arrhythmias during occlusion and increased survival (0% vs. 50 and 92%) upon reperfusion. There were also significant decreases in superoxide and NT levels in the nitrite treated dogs. Compared with controls, increased SNO was found only in NaNO2-PR dogs, whereas S-glutathionylation occurred primarily in NaNO2-PO dogs. Conclusions Intravenous infusion of nitrite profoundly reduced the severity of ventricular arrhythmias resulting from acute ischaemia and reperfusion in anaesthetized dogs. This effect, among several others, may result from an NO-mediated reduction in oxidative stress, perhaps through protein SNO and/or S-glutathionylation. PMID:25909651

  13. The antilisterial effect of Leuconostoc carnosum 4010 and leucocins 4010 in the presence of sodium chloride and sodium nitrite examined in a structured gelatin system.

    PubMed

    Hornbaek, Tina; Brocklehurst, Tim F; Budde, Birgitte Bjørn

    2004-04-15

    To further enhance biopreservation of meat products, the antilisterial effect of the newly described protective culture Leuconostoc carnosum 4010 and its bacteriocins, leucocins 4010, was examined in the presence of sodium chloride and sodium nitrite in a solid matrix using a structured gelatin system. Interaction between Listeria monocytogenes 4140 and Leuc. carnosum 4010 or the leucocins 4010-resistant mutant L. monocytogenes 4140P showed that the inhibitory effect of Leuc. carnosum 4010 in the gelatin system was caused by the production and activity of leucocins 4010. The presence of sodium chloride (2.5% w/v) and sodium nitrite (60 mg/l) reduced the antilisterial effect of Leuc. carnosum 4010 in the structured gel system compared to the use of Leuc. carnosum 4010 alone. Investigations carried out at 10 degrees C showed that the lag phase of L. monocytogenes 4140 in the presence of Leuc. carnosum 4010 was reduced from 71 to 58 h by the addition of sodium chloride and to 40 h by the addition of sodium nitrite. Addition of sodium chloride increased the maximum specific growth rate of L. monocytogenes 4140 in the presence of Leuc. carnosum 4010 from 0.02 to 0.06 h(-1), whereas no change was observed by the addition of sodium nitrite. Compared to the antilisterial effect of leucocins 4010 alone, the addition of sodium chloride (2.5%, w/v) decreased the antilisterial effect at high concentrations of leucocins 4010 (5.3 and 10.6 AU/ml) as measured after 11 days of incubation at 10 degrees C. In gels with added leucocins 4010, the most pronounced reduction in growth of L. monocytogenes 4140 was observed at the highest concentration of leucocins 4010 (10.6 AU/ml) together with sodium nitrite (60 mg/l). More detailed information on the lag phase and the maximum specific growth rate of single colonies of L. monocytogenes 4140 in the presence of leucocins 4010 was obtained using microscopy and image analysis. No pronounced difference in the growth of single colonies was

  14. Listeria monocytogenes behaviour and quality attributes during sausage storage affected by sodium nitrite, sodium lactate and thyme essential oil.

    PubMed

    Blanco-Lizarazo, Carla María; Betancourt-Cortés, Rubén; Lombana, Angélica; Carrillo-Castro, Katerine; Sotelo-Díaz, Indira

    2017-04-01

    The effects of the addition of nitrite at 200 ppm (N), sodium lactate 1.5% (L) and thyme essential oil at 100 ppm (T1) on Listeria monocytogenes behaviour and ATPase activity inhibition were evaluated, as well as lipid oxidation through the quantification of malonaldehydes, in sausage stored at 8 ℃ for 41 days and at 30 ℃ for 14 days. The changes in the colour profile were performed during storage time at 8 ℃. Quantitative descriptive sensory analyses were performed after two days at 4 ℃. At 8 ℃, the treatments with the highest inhibition on L. monocytogenes were L and N, without significant differences. In turn, at 30 ℃, the bacterium was most inhibited with treatment L, followed by T1 and N, without significant differences. A 44.1% and 19% inhibition of ATPase activity was detected in L and T1 treatments, respectively. At 8 ℃ and 30 ℃, malonaldehydes content was not different between the treatments. N presented the highest values of a* and concentration of metmyoglobin after 41 days at 8 ℃. The panel detected differences between T1 and N for the aroma in the descriptors spices and herbal.

  15. Inhibition of vacuolation toxin activity of Helicobacter pylori by iodine, nitrite and potentiation by sodium chloride, sterigmatocystin and fluoride.

    PubMed

    Ma, Fengjuan; Zhao, Wenyuan; Kudo, Masanobu; Aoki, Kazuo; Misumi, Junichi

    2002-10-01

    The toxin VacA produced by Helicobacter pylori is an important determinant of virulence. VacA causes vacuolation of cultured cells such as HeLa cells. Iodine, nitrite, sodium chloride, thiocyanate and fungus toxin sterigmatocystin are universally present in nature and could possibly be related to carcinogenesis of the stomach. The present study was designed to examine the effects of the above-mentioned compound on VacA-induced vacuolation of HeLa cells, which was quantitated using the neutral red uptake assay. VacA-induced vacuolation was inhibited by BafA1 and NPPB. Formation of large vacuoles was inhibited in the presence of iodine, nitrite, but enhanced by sodium chloride, thiocyanate, fluoride and sterigmatocystin. Our results indicate that VacA toxin may interact with other gastric cancer risk factors present naturally in the environment, and suggest that those compounds may modulate the development of gastric cancer induced by H. pylori.

  16. Susceptibility of Nile tilapia (Oreochromis niloticus) fed dietary sodium chloride to nitrite toxicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Juvenile Nile tilapia (Oreochromis niloticus) were fed diets supplemented with 0 or 6% NaCl for 10 weeks. Tilapia were exposed to approximately 21 mg/l nitrite-N after five and ten weeks of feeding to determine the effect of dietary NaCl supplementation on resistance to nitrite toxicity. Fish were...

  17. Sodium nitrite protects against kidney injury induced by brain death and improves post-transplant function.

    PubMed

    Kelpke, Stacey S; Chen, Bo; Bradley, Kelley M; Teng, Xinjun; Chumley, Phillip; Brandon, Angela; Yancey, Brett; Moore, Brandon; Head, Hughston; Viera, Liliana; Thompson, John A; Crossman, David K; Bray, Molly S; Eckhoff, Devin E; Agarwal, Anupam; Patel, Rakesh P

    2012-08-01

    Renal injury induced by brain death is characterized by ischemia and inflammation, and limiting it is a therapeutic goal that could improve outcomes in kidney transplantation. Brain death resulted in decreased circulating nitrite levels and increased infiltrating inflammatory cell infiltration into the kidney. Since nitrite stimulates nitric oxide signaling in ischemic tissues, we tested whether nitrite therapy was beneficial in a rat model of brain death followed by kidney transplantation. Nitrite, administered over 2 h of brain death, blunted the increased inflammation without affecting brain death-induced alterations in hemodynamics. Kidneys were transplanted after 2 h of brain death and renal function followed over 7 days. Allografts collected from nitrite-treated brain-dead rats showed significant improvement in function over the first 2 to 4 days after transplantation compared with untreated brain-dead animals. Gene microarray analysis after 2 h of brain death without or with nitrite therapy showed that the latter significantly altered the expression of about 400 genes. Ingenuity Pathway Analysis indicated that multiple signaling pathways were affected by nitrite, including those related to hypoxia, transcription, and genes related to humoral immune responses. Thus, nitrite therapy attenuates brain death-induced renal injury by regulating responses to ischemia and inflammation, ultimately leading to better post-transplant kidney function.

  18. Inhibition of nitrite-induced toxicity in channel catfish by calcium chloride and sodium chloride

    USGS Publications Warehouse

    Tommasso J.R., Wright; Simco, B.A.; Davis, K.B.

    1980-01-01

    Environmental chloride has been shown to inhibit methemoglobin formation in fish, thereby offering a protective effect against nitrite toxicity. Channel catfish (Ictalurus punctatus) were simultaneously exposed to various environmental nitrite and chloride levels (as either CaCl2 or NaCl) in dechlorinated tap water (40 mg/L total hardness, 47 mg/L alkalinity, 4 mg/L chloride, pH = 6.9-7.1, and temperature 21-24°C). Methemoglobin levels in fish simultaneously exposed to 2.5 mg/L nitrite and up to 30 mg/L chloride as either CaCl2 or NaCl were similar but significantly lower than in unprotected fish. Exposure to 10 mg/L nitrite and 60 mg/L chloride resulted in methemoglobin levels similar to those of the controls; most unprotected fish died. Fish exposed to 10 mg/L nitrite had significantly lower methemoglobin levels when protected with 15.0 mg/L chloride as CaCl2 than with NaCl. Fish exposed to nitrite in the presence of 60 mg/L chloride (as either CaCl2 or NaCl) had similar 24-h LC50 values that were significantly elevated above those obtained in the absence of chloride. Calcium had little effect on tolerance to nitrite toxicity in channel catfish in contrast to its large effect reported in steelhead trout (Salmo gairdneri).

  19. Changes in the Physico-chemical and Microbial Quality during the Production of Pastırma Cured with Different Levels of Sodium Nitrite

    PubMed Central

    2016-01-01

    Pastırma, a dry-cured meat product, is produced from the whole muscle and/or muscles obtained from certain parts of beef and water buffalo carcasses. The purpose of this study was to determine the effects of different levels of sodium nitrite on changes in the physicochemical and microbial quality during the production of pastırma. The changes in residual nitrite, salt, pH, moisture, thiobarbutiric acid reactive substances (TBARS), colour (L*, a*, b*), total aerobic mesophilic bacteria (TAMB), lactic acid bacteria (LAB), Micrococcus/Staphylococcus (M/S), mould-yeast (M-Y), and Enterobacteriaceae counts of pastırma with 0, 50, 100 and 150 ppm sodium nitrite were determined during the production. The nitrite levels and the production stages had significant effects (p<0.01) on residual nitrite, TBARS, pH, salt, and colour values. The TBARS values of the pastırma with nitrite were significantly lower (p<0.05) than the control. The final TAMB, LAB, M/S, and M-Y counts of pastırma with 150 ppm nitrite were significantly (p<0.05) lower than the control. Also, the a* (relative redness) values of control pastırma were significantly lower (p<0.05) than the pastırma with nitrite. The production stages had a significant effect (p<0.01) on the moisture. PMID:27857537

  20. Changes in the Physico-chemical and Microbial Quality during the Production of Pastırma Cured with Different Levels of Sodium Nitrite.

    PubMed

    Aksu, Muhammet Irfan; Erdemir, Ebru; Çakıcı, Neslihan

    2016-10-31

    Pastırma, a dry-cured meat product, is produced from the whole muscle and/or muscles obtained from certain parts of beef and water buffalo carcasses. The purpose of this study was to determine the effects of different levels of sodium nitrite on changes in the physicochemical and microbial quality during the production of pastırma. The changes in residual nitrite, salt, pH, moisture, thiobarbutiric acid reactive substances (TBARS), colour (L*, a*, b*), total aerobic mesophilic bacteria (TAMB), lactic acid bacteria (LAB), Micrococcus/Staphylococcus (M/S), mould-yeast (M-Y), and Enterobacteriaceae counts of pastırma with 0, 50, 100 and 150 ppm sodium nitrite were determined during the production. The nitrite levels and the production stages had significant effects (p<0.01) on residual nitrite, TBARS, pH, salt, and colour values. The TBARS values of the pastırma with nitrite were significantly lower (p<0.05) than the control. The final TAMB, LAB, M/S, and M-Y counts of pastırma with 150 ppm nitrite were significantly (p<0.05) lower than the control. Also, the a* (relative redness) values of control pastırma were significantly lower (p<0.05) than the pastırma with nitrite. The production stages had a significant effect (p<0.01) on the moisture.

  1. Urinary excretion of N-nitroso compounds in rats fed sodium nitrite and/or hot dogs.

    PubMed

    Zhou, Lin; Anwar, Muhammad M; Zahid, Muhammad; Shostrom, Valerie; Mirvish, Sidney S

    2014-10-20

    Nitrite-treated meat is a reported risk factor for colon cancer. Mice that ingested sodium nitrite (NaNO2) or hot dogs (a nitrite-treated product) showed increased fecal excretion of apparent N-nitroso compounds (ANC). Here, we investigated for the first time whether rats excrete increased amounts of ANC in their urine after they are fed NaNO2 and/or hot dogs. Rats were treated for 7 days with NaNO2 in drinking water or were fed hot dogs. Their 24 h urine samples were analyzed for ANC by thermal energy analysis on days 1-4 after nitrite or hot dog treatment was stopped. For two rats fed 480 mg NaNO2/L drinking water, mean urinary ANC excretion on days 1-4 was 30, 5.2, 2.5, and 0.8 nmol/day, respectively. For two to eight rats/dose given varied NaNO2 doses, mean urinary ANC output on day 1 increased from 0.9 (for no nitrite) to 37 (for 1000 mg NaNO2/L drinking water) nmol ANC/day. Urine samples of four rats fed 40-60% hot dogs contained 12-13 nmol ANC on day 1. Linear regression analysis showed highly significant correlations between urinary ANC excretion on day 1 after stopping treatment and varied (a) NaNO2 level in drinking water for rats fed semipurified or commercials diet and (b) hot dog levels in the diet. Some correlations remained significant up to 4 days after nitrite treatment was stopped. Urinary output of ANC precursors (compounds that yield ANC after mild nitrosation) for rats fed semipurified or commercial diet was 11-17 or 23-48 μmol/day, respectively. Nitrosothiols and iron nitrosyls were not detected in urinary ANC and ANCP. Excretion of urinary ANC was about 60% of fecal ANC excretion for 1 to 2 days after NaNO2 was fed. Administered NaNO2 was not excreted unchanged in rat urine. We conclude that urinary ANC excretion in humans could usefully be surveyed to indicate exposure to N-nitroso compounds.

  2. Sodium nitrite exerts an antihypertensive effect and improves endothelial function through activation of eNOS in the SHR

    PubMed Central

    Ling, Wei Chih; Murugan, Dharmani Devi; Lau, Yeh Siang; Vanhoutte, Paul M.; Mustafa, Mohd Rais

    2016-01-01

    Sodium nitrite (NaNO2) induces relaxation in isolated arteries partly through an endothelium-dependent mechanism involving NO-eNOS-sGC-cGMP pathway. The present study was designed to investigate the effect of chronic NaNO2 administration on arterial systolic blood pressure (SBP) and vascular function in hypertensive rats. NaNO2 (150 mg L−1) was given in drinking water for four weeks to spontaneously (SHR) and Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) treated hypertensive SD rats. Arterial SBP and vascular function in isolated aortae were studied. Total plasma nitrate/nitrite and vascular cyclic guanosine monophosphate (cGMP) levels were measured using commercially available assay kits. Vascular nitric oxide (NO) levels were evaluated by DAF-FM fluorescence while the proteins involved in endothelial nitric oxide synthase (eNOS) activation was determined by Western blotting. NaNO2 treatment reduced SBP, improved the impaired endothelium-dependent relaxation, increased plasma total nitrate/nitrite level and vascular tissue NO and cGMP levels in SHR. Furthermore, increased presence of phosphorylated eNOS and Hsp-90 was observed in NaNO2-treated SHR. The beneficial effect of nitrite treatment was not observed in L-NAME treated hypertensive SD rats. The present study provides evidence that chronic treatment of genetically hypertensive rats with NaNO2 improves endothelium-dependent relaxation in addition to its antihypertensive effect, partly through mechanisms involving activation of eNOS. PMID:27616322

  3. In silico Logistic Model for Table Olive Related Microorganisms As a Function of Sodium Metabisulphite, Cinnamaldehyde, pH, and Type of Acidifying Agent

    PubMed Central

    Romero-Gil, Verónica; Garrido-Fernández, Antonio; Arroyo-López, Francisco N.

    2016-01-01

    A probabilistic/logistic model, based on binary data (growth/no growth), was used to assess the effects of sodium metabisulphite (SM) and cinnamaldehyde (CIN; 0–1000 mg/L) against the main microbial groups found in table olive environment [lactic acid bacteria (LAB), yeasts, and Enterobacteriaceae], according to pH (range 3.5–5.0), and type of acidifying agent (HCl or pyruvic acid). The inhibitory effect of SM depended on the pH while that of CIN was scarcely influenced by it (except for LAB). LAB were more sensitive to SM, while yeasts were to CIN. The use of pyruvic acid for correction of pH always produced a reduction (compared to HCl) of the inhibitory power of both preservatives. The in silico models for HCl showed that, at pH 4.0, and growth probability 0.01, the LAB population might be inhibited by the presence in the medium of 150 mg/L SM or 1000 mg/L CIN, while in the case of yeasts, 450 mg/L SM, or 150 mg/L CIN are required. No growth of Enterobacteriaceae was observed at this (or lower) pH level. The results obtained may contribute to the stabilization of non-thermally treated table olive packaging. PMID:27630627

  4. Hot water postprocess pasteurization of cook-in-bag turkey breast treated with and without potassium lactate and sodium diacetate and acidified sodium chlorite for control of Listeria monocytogenes.

    PubMed

    Luchansky, John B; Cocoma, George; Call, Jeffrey E

    2006-01-01

    Surface pasteurization and food-grade chemicals were evaluated for the ability to control listeriae postprocess on cook-in-bag turkey breasts (CIBTB). Individual CIBTB were obtained directly from a commercial manufacturer and surface inoculated (20 ml) with a five-strain cocktail (ca. 7.0 log) of Listeria innocua. In each of two trials, the product was showered or submerged for up to 9 min with water heated to 190, 197, or 205 degrees F (ca. 87.8, 91.7, or 96.1 degrees C) in a commercial pasteurization tunnel. Surviving listeriae were recovered from CIBTB by rinsing and were then enumerated on modified Oxford agar plates following incubation at 37 degrees C for 48 h. As expected, higher water temperatures and longer residence times resulted in a greater reduction of L. innocua. A ca. 2.0-log reduction was achieved within 3 min at 205 and 197 degrees F and within 7 min at 190 degrees E In related experiments, the following treatments were evaluated for control of Listeria monocytogenes on CIBTB: (i) a potassium lactate-sodium diacetate solution (1.54% potassium lactate and 0.11% sodium diacetate) added to the formulation in the mixer and 150 ppm of acidified sodium chlorite applied to the surface with a pipette, or (ii) a potassium lactate-sodium diacetate solution only, or (iii) no potassium lactate-sodium diacetate solution and no acidified sodium chlorite. Each CIBTB was inoculated (20 ml) with ca. 5 log CFU of a five-strain mixture of L. monocytogenes and then vacuum sealed. In each of two trials, half of the CIBTB were exposed to 203 degrees F water for 3 min in a pasteurization tunnel, and the other half of the CIBTB were not; then, all CIBTB were stored at 4 degrees C for up to 60 days, and L. monocytogenes was enumerated by direct plating onto modified Oxford agar. Heating resulted in an initial reduction of ca. 2 log CFU of L. monocytogenes per CIBTB. For heated CIBTB, L. monocytogenes increased by ca. 2 log CFU per CIBTB in 28 (treatment 1), 28 (treatment

  5. Quantification of toxin-encoding mRNA from Clostridium botulinum type E in media containing sorbic acid or sodium nitrite by competitive RT-PCR.

    PubMed

    Sharkey, Freddie H; Markos, Spiros I; Haylock, Richard W

    2004-03-19

    Competitive reverse transcription polymerase chain reaction (cRT-PCR) was used to quantify the toxin-encoding mRNA production of a Clostridium botulinum type E strain in media containing either sorbic acid or sodium nitrite. A 10-fold reduction in toxin mRNA production and a 25-fold reduction in the proportion of toxin mRNA to total RNA, was estimated when either 1 mg ml(-1) sorbic acid or 100 microg ml(-1) sodium nitrite were added to the medium at pH 7.0.

  6. Comparison of the treatment of cyanide poisoning in the cynomolgus monkey with sodium nitrite of 4-dimethylaminophenol (4-dmap), with and without sodium thiosulfate. Technical report, April 1979-September 1981

    SciTech Connect

    Stemler, F.W.; Groff, W.A.; Kaminskis, A.; Johnson, R.P.; Froehlich, H.L.

    1994-02-01

    Two methemoglobin generating compounds, sodium nitrite (iv) or 4-dimethylaminophenol (4-DMAP) (im), with and without sodium thiosulfate (iv), were compared as post-treatment therapy in anesthetized monkeys poisoning with cyanide. Arterial blood samples were taken before and after an injection of sodium cyanide (8.4 mg/kg) and treatment for analyses of blood cyanide, plasma cyanide, thiocyanate and methemoglobin content. Physiologic parameters were monitored in these treated cyanide-poisoned animals. The time course of methemoglobin formation and physiologic parameters were also monitored in animals receiving only 4-DMAP or sodium nitrite. A maximal methemoglobin level was observed at 30 minutes following injection of 4-DMAP, and 60 minutes post injection with sodium nitrite. Volumes of distribution (Vd) of cyanide were calculated from the concentrations of cyanide in blood samples and doses of cyanide injected. Although 4-DMAP forms methemoglobin more rapidly than sodium nitrite, both compounds form methemoglobin quickly enough to provide protection against cyanide poisoning. The protection offered by either compound against the lethal effects of cyanide was potentiated when used in combination with sodium thiosulfate.

  7. The effect of pH and nitrite concentration on the antimicrobial impact of celery juice concentrate compared with conventional sodium nitrite on Listeria monocytogenes.

    PubMed

    Horsch, A M; Sebranek, J G; Dickson, J S; Niebuhr, S E; Larson, E M; Lavieri, N A; Ruther, B L; Wilson, L A

    2014-01-01

    The objectives of this study were to evaluate the impact of pH and nitrite from celery juice concentrate (CJ) on the growth of Listeria monocytogenes in broth and on ham slices, and to evaluate the impact of pH and nitrite from CJ on quality attributes of the ham. The pH of both broth and ham were increased by the addition of CJ. The CJ was less effective than conventional nitrite at 100 mg/kg nitrite in broth, but in ham, the CJ treatments at both 100 and 200 mg/kg resulted in growth of L. monocytogenes (p>0.05) similar to that of the conventional nitrite at the same concentrations. Reducing the pH of CJ before addition to the ham had greater impact on L. monocytogenes growth at 200 mg/kg nitrite than at 100 mg/kg. Celery juice concentrate may increase meat product pH which could have implications for the antimicrobial impact of nitrite in some products.

  8. Sodium nitrite induces acute central nervous system toxicity in guinea pigs exposed to systemic cell-free hemoglobin.

    PubMed

    Buehler, Paul W; Butt, Omer I; D'Agnillo, Felice

    2011-06-10

    Systemic cell-free hemoglobin (Hb) released via hemolysis disrupts vascular homeostasis, in part, through the scavenging of nitric oxide (NO). Sodium nitrite (NaNO(2)) therapy can attenuate the hypertensive effects of Hb. However, the chemical reactivity of NaNO(2) with Hb may enhance heme- or iron-mediated toxicities. Here, we investigate the effect of NaNO(2) on the central nervous system (CNS) in guinea pigs exposed to systemic cell-free Hb. Intravascular infusion of NaNO(2), at doses sufficient to alleviate Hb-mediated blood pressure changes, reduced the expression of occludin, but not zona occludens-1 (ZO-1) or claudin-5, in cerebral tight junctions 4h after Hb infusion. This was accompanied by increased perivascular heme oxygenase-1 expression, neuronal iron deposition, increased astrocyte and microglial activation, and reduced expression of neuron-specific nuclear protein (NeuN). These CNS changes were not observed in animals treated with Hb or NaNO(2) alone. Taken together, these findings suggest that the use of nitrite salts to treat systemic Hb exposure may promote acute CNS toxicity.

  9. Exploring the Ideal Gas Law through a Quantitative Gasometric Analysis of Nitrogen Produced by the Reaction of Sodium Nitrite with Sulfamic Acid

    ERIC Educational Resources Information Center

    Yu, Anne

    2010-01-01

    The gasometric analysis of nitrogen produced in a reaction between sodium nitrite, NaNO[superscript 2], and sulfamic acid, H(NH[superscript 2])SO[superscript 3], provides an alternative to more common general chemistry experiments used to study the ideal gas law, such as the experiment in which magnesium is reacted with hydrochloric acid. This…

  10. Effect of meat ingredients (sodium nitrite and erythorbate) and processing (vacuum storage and packaging atmosphere) on germination and outgrowth of Clostridium perfringens spores in ham during abusive cooling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of nitrite and erythorbate on Clostridium perfringens spore germination and outgrowth in ham during abusive cooling (15 h) was evaluated. Ham was formulated with ground pork, NaNO2 (0, 50, 100, 150 or 200 ppm) and sodium erythorbate (0 or 547 ppm). Ten grams of meat (stored at 5C for 3 or...

  11. The interaction of phosphate coatings on a carbon steel surface with a sodium nitrite and silicate solution

    NASA Astrophysics Data System (ADS)

    Ramanauskas, R.; Girčienė, O.; Gudavičiūtė, L.; Selskis, A.

    2015-02-01

    Mono-cation PZn, bi-cation PZnCa, PZnNi and three-cation PZnNiMn crystalline phosphate coatings were modified with an inhibitor mixture: a sodium nitrite and sodium silicate solution with the aim to establish the reasons of protective ability enhancement of passive films on a carbon steel surface in an alkaline media. The SEM, EDS, XRD and XPS techniques were applied for the structural, phase and composition characterization of the phosphate coatings, voltammetric measurements were carried out to determine the passive layer protective ability, while EIS studies yielded information on the coatings porosity. Compact films of Si compounds were formed on the surface of the phosphate coatings during their modification procedure, which was accompanied by an increase in the protective ability of phosphate layer. A higher porosity and regularly shaped crystallites of the phosphate layer were favourable for accumulation of a greater amount of Si in the modified coatings. The protective ability of the modified coatings remains fairly pronounced, which testifies that the phosphate layer porosity is not the only factor influencing the corrosion behaviour of the coating. The difference in the nature of Si compounds comprising modified phosphate coatings leads to the differences in their protective ability.

  12. Efficacy of UV, acidified sodium hypochlorite, and mild heat for decontamination of surface and infiltrated Escherichia coli O157:H7 on green onions and baby spinach.

    PubMed

    Durak, M Zeki; Churey, John J; Worobo, Randy W

    2012-07-01

    Produce-associated foodborne illnesses outbreaks have highlighted the need for more effective decontamination methods to ensure the safety of fresh produce. The main objective of this study was to evaluate the individual and combined efficacies of germicidal UV light (12.5 to 500 mJ/cm(2)), acidified sodium hypochlorite (ASC 10 to 200 ppm), and mild heat (40 to 50°C) for decontaminating green onions and baby spinach infected with Escherichia coli O157:H7. Samples were inoculated by spot and dip inoculation methods to mimic surface and infiltrated E. coli O157:H7 contamination, respectively. In green onions and baby spinach, the individual efficacies of UV, ASC, and mild-heat treatments varied based on the produce type and contamination method. Following analysis of the efficacies of the single treatments, a combined treatment with 125 mJ/cm(2) UV and 200 ppm of ASC at 50°C was selected for spot-inoculated green onions, and a combined treatment with 125 mJ/cm(2) UV and 200 ppm of ASC at 20°C was selected for spot- and dip-inoculated baby spinach. While a >5-log reduction was achieved with the combination treatment for spot-inoculated green onions with an initial contamination level of 7.2 log CFU per spot, the same treatment reduced E. coli O157:H7 populations below the detection limit (<1 log) on green onions spot inoculated at a lower contamination level (4.3 log CFU per spot). On spot- and dip-inoculated baby spinach, the combined treatment reduced E. coli O157:H7 populations by 2.8 log CFU per spot and 2.6 log CFU/g, respectively. The combined treatment of 500 mJ/cm(2) UV and 200 ppm of ASC at 50°C selected for the decontamination of dip-inoculated green onions resulted in a 2.2-log CFU/g reduction. These findings suggest that when foodborne pathogens contaminate produce and subsequently infiltrate, attach to, or become localized into protected areas, the individual or combined applications of UV, ASC, and mild-heat treatments have limited decontamination

  13. Topical sodium nitrite for chronic leg ulcers in patients with sickle cell anaemia: a phase 1 dose-finding safety and tolerability trial

    PubMed Central

    Minniti, Caterina P; Gorbach, Alexander M; Xu, Dihua; Hon, Yuen Yi; Delaney, Kara-Marie; Seidel, Miles; Malik, Nitin; Peters-Lawrence, Marlene; Cantilena, Carly; Nichols, James S; Mendelsohn, Laurel; Conrey, Anna; Grimes, George; Kato, Gregory J

    2015-01-01

    Summary Background Well-tolerated and effective treatments are needed for chronic leg ulcers in sickle cell anaemia. Topical sodium nitrite, a known nitric oxide donor, enhances blood flow in ulcers and has known bacteriostatic effects. We aimed to assess the safety, tolerability, and pharmacokinetics of topical sodium nitrite in patients with sickle cell disease and chronic leg ulcers. Methods We enrolled adult patients from an ambulatory clinic at the National Institutes of Health (Bethesda, MD, USA) with sickle cell anaemia with leg ulcers (with a surface area of 2.5–100 cm2) persisting for at least 4 weeks into a safety and tolerability phase 1 dose-escalation trial of topical sodium nitrite. Increasing concentrations of sodium nitrite cream were applied twice weekly for 4 weeks to one ulcer per patient at five dose levels (0.5%, 1%, 1.5%, 1.8%, and 2%). The primary endpoints were safety and tolerability, with secondary endpoints of pharmacokinetics, blood flow, and wound healing. Pain relief was analysed post hoc. Endpoints were analysed over time for the whole study population and according to dose level. This study is registered with ClinicalTrials.gov, number NCT01316796. Findings Between April 4, 2011, and March 19, 2013, we enrolled 18 adult patients with sickle cell anaemia and leg ulcers into our trial. We assigned three patients into each cohort, and each cohort was treated with a different concentration of sodium nitrite cream (cohort 1: 0.5%, cohort 2: 1.0%, cohort 3: 1.5%, and cohort 4: 2.0%). Patients were not enrolled into the next cohort dose until we were able to establish that no dose-limiting toxicities were observed. An additional six patients were enrolled to cohort 3a: 1.8%, after two patients in cohort 4 had asymptomatic drops in diastolic blood pressure. No grade 3–4 adverse events were observed, and there were no serious adverse events or dose-limiting side-effects. Pharmacokinetic analysis showed that systemic absorption of sodium

  14. Sodium nitrite induces acute central nervous system toxicity in guinea pigs exposed to systemic cell-free hemoglobin

    SciTech Connect

    Buehler, Paul W.; Butt, Omer I.; D'Agnillo, Felice

    2011-06-10

    Highlights: {yields} Toxicological implications associated with the use of NaNO{sub 2} therapy to treat systemic cell-free Hb exposure are not well-defined. {yields} Systemic Hb exposure followed by NaNO{sub 2} infusion induces acute CNS toxicities in guinea pigs. {yields} These CNS effects were not reproduced by the infusion of cell-free Hb or NaNO{sub 2} alone. {yields} NaNO{sub 2}-mediated oxidation of cell-free Hb may play a causative role in the observed CNS changes. -- Abstract: Systemic cell-free hemoglobin (Hb) released via hemolysis disrupts vascular homeostasis, in part, through the scavenging of nitric oxide (NO). Sodium nitrite (NaNO{sub 2}) therapy can attenuate the hypertensive effects of Hb. However, the chemical reactivity of NaNO{sub 2} with Hb may enhance heme- or iron-mediated toxicities. Here, we investigate the effect of NaNO{sub 2} on the central nervous system (CNS) in guinea pigs exposed to systemic cell-free Hb. Intravascular infusion of NaNO{sub 2}, at doses sufficient to alleviate Hb-mediated blood pressure changes, reduced the expression of occludin, but not zona occludens-1 (ZO-1) or claudin-5, in cerebral tight junctions 4 h after Hb infusion. This was accompanied by increased perivascular heme oxygenase-1 expression, neuronal iron deposition, increased astrocyte and microglial activation, and reduced expression of neuron-specific nuclear protein (NeuN). These CNS changes were not observed in animals treated with Hb or NaNO{sub 2} alone. Taken together, these findings suggest that the use of nitrite salts to treat systemic Hb exposure may promote acute CNS toxicity.

  15. Synthesis and characterization of secondary nitrosamines from secondary amines using sodium nitrite and p-toluenesulfonic acid.

    PubMed

    Miró Sabaté, Carles; Delalu, Henri

    2015-03-01

    We synthesized nitrosamines (R2N-NO) with R = iPr (1), nPr (2), nBu (3), and hydroxyethyl (4) from the amine using sodium nitrite/p-toluenesulfonic acid in CH2Cl2. The rate of formation of 1-4 increases in the direction iPr

  16. [Case followed by delayed loss of consciousness after exposure to hydrogen sulfide that was treated with intermittent administration of sodium nitrite].

    PubMed

    Fujino, Yasuhisa; Inoue, Yoshihiro; Onodera, Makoto; Kikuchi, Satoshi; Endo, Jin; Endo, Shigeatsu; Fujita, Yuji

    2010-12-01

    A 49-year-old man lost consciousness after being accidentally exposed to what was probably hydrogen sulfide gas while performing maintenance on a machine producing feather meal. He was immediately taken to the hospital. Upon admission, his consciousness level was 14 (E4V4M6) on the Glasgow Coma Scale (GCS), but it subsequently decreased, and the patient was intubated when his respirations became depressed as well. About 5 hours after the initial incident, he was transferred to our department. His consciousness level was GCS 9 (E2V2M5), his blood pressure was 95/78 mmHg, and his heart rate was 90 beats per min. There was no metabolic acidosis. Mechanical ventilation was begun and 10% sodium nitrite was intermittently administered intravenously, with the goal of lowering arterial blood methemoglobin saturation to 20%. Two days following admission, the patient regained full consciousness and sodium nitrite administration was stopped. The following day mechanical ventilation was also discontinued. This patient exhibited severe recurring neurologic symptoms without metabolic acidosis; thus, the manifestations of toxicity in this case might have been due to the direct neurologic toxicity of hydrogen sulfide, hypoxia, or delayed post-ischemic cerebral hypoperfusion syndrome. The patient made a full recovery without any sequelae; therefore we would like to hypothesize that repetitive intravenous administration of sodium nitrite is effective in cases of hydrogen sulfide exposure.

  17. [The influence of sodium nitrite on the osmoresistance of Chinese hamster cells].

    PubMed

    Bol'shakova, O I; Sverdlov, A G; Timoshenko, S I; Nikanorova, N G; Grachev, S A

    2007-01-01

    We have previously demonstrated that incubation of V-79 cells in the medium containing the nitric oxide donor, NaNO2, increases cell resistance to damaging effect of gamma-rays, UV radiation and hyperthermia. In the present study, we investigated the effects of the nitric oxide donor on the sensitivity of V-79 cells to changes in osmomolarity of the medium by adding different amounts of sodium chloride or water. We found that pretreatment of the cells with NaNO2 resulted in a significant increase in the number of growing cells in 48 h after the treatment. The osmomolarity-dependent morphological changes in cultured cells were also substantially diminished following NaNO2 treatment. This effect could be observed under both hyper- and hypoosmosis, and was dependent on concentration of sodium chloride in hypertonic medium (being maximal under 0.17 M NaCl) and on the amount of water in hypotonic medium (being maximal under 1.1 times the dilution with water). In the experiments with increased osmomolarity, we found that the observed increase in the number of growing cells following NaNO2 treatment was accompanied with a significant increase of the mitotic index. These findings indicate that nitric oxide increases cell resistance to the damaging effects of osmotic shock in the way which is similar to the protective effect of these molecules against radiation and hyperthermia. Similarities in the effects of NaNO2 under different conditions leading to cell damage suggest that nitric oxide might serve as the universal factor participating in recovery of damaged cells and mediating increased cellular resistance to the damaging conditions.

  18. Quantitative interaction effects of carbon dioxide, sodium chloride, and sodium nitrite on neurotoxin gene expression in nonproteolytic Clostridium botulinum type B.

    PubMed

    Lövenklev, Maria; Artin, Ingrid; Hagberg, Oskar; Borch, Elisabeth; Holst, Elisabet; Rådström, Peter

    2004-05-01

    The effects of carbon dioxide, sodium chloride, and sodium nitrite on type B botulinum neurotoxin (BoNT/B) gene (cntB) expression in nonproteolytic Clostridium botulinum were investigated in a tryptone-peptone-yeast extract (TPY) medium. Various concentrations of these selected food preservatives were studied by using a complete factorial design in order to quantitatively study interaction effects, as well as main effects, on the following responses: lag phase duration (LPD), growth rate, relative cntB expression, and extracellular BoNT/B production. Multiple linear regression was used to set up six statistical models to quantify and predict these responses. All combinations of NaCl and NaNO(2) in the growth medium resulted in a prolonged lag phase duration and in a reduction in the specific growth rate. In contrast, the relative BoNT/B gene expression was unchanged, as determined by the cntB-specific quantitative reverse transcription-PCR method. This was confirmed when we measured the extracellular BoNT/B concentration by an enzyme-linked immunosorbent assay. CO(2) was found to have a major effect on gene expression when the cntB mRNA levels were monitored in the mid-exponential, late exponential, and late stationary growth phases. The expression of cntB relative to the expression of the 16S rRNA gene was stimulated by an elevated CO(2) concentration; the cntB mRNA level was fivefold greater in a 70% CO(2) atmosphere than in a 10% CO(2) atmosphere. These findings were also confirmed when we analyzed the extracellular BoNT/B concentration; we found that the concentrations were 27 ng x ml(-1). unit of optical density(-1) in the 10% CO(2) atmosphere and 126 ng x ml(-1). unit of optical density(-1) in the 70% CO(2) atmosphere.

  19. Evaluation of the influence of proline, hydroxyproline or pyrrolidine in the presence of sodium nitrite on N-nitrosamine formation when heating cured meat.

    PubMed

    Drabik-Markiewicz, G; Dejaegher, B; De Mey, E; Impens, S; Kowalska, T; Paelinck, H; Vander Heyden, Y

    2010-01-11

    N-nitrosamines are meant to be probable or possible carcinogenic components, possibly formed out of a reaction between nitrite and N-containing substances such as amino acids and secondary amines. Nitrite is often used for processing meat products because of its colouring and antimicrobial properties. During this experimental setup, the influence of proline, hydroxyproline or pyrrolidine on N-nitrosamine formation in meat samples was evaluated. The N-nitrosamines concentrations were measured with gas chromatography-thermal energy analyzer. Only the concentrations of N-nitrosodimethylamine and N-nitrosopyrrolidine were found above the limit of detection in a number of tested experimental conditions. The concentration of these two N-nitrosamines was modelled as a function of temperature and nitrite concentration for different situations (presence or absence of added natural N-containing meat components). It could be concluded that proline and pyrrolidine promoted the formation of N-nitrosopyrrolidine. It could also be confirmed that the higher the temperature of the meat processing procedure and the higher the sodium nitrite amounts added, the higher were the yields of the respective N-nitrosamines.

  20. In vitro influence of D/L-lactic acid, sodium chloride and sodium nitrite on the infectivity of feline calicivirus and of ECHO virus as potential surrogates for foodborne viruses.

    PubMed

    Straube, J; Albert, T; Manteufel, J; Heinze, J; Fehlhaber, K; Truyen, U

    2011-11-15

    The importance of foodborne viruses is increasingly recognized. Thus, the effect of commonly used food preservation methods on the infectivity of viruses is questioned. In this context, we investigated the antiviral properties of D,L-lactic acid, sodium chloride and sodium nitrite by in vitro studies. Two model viruses, Feline Calicivirus (FCV) and Enteric Cytophatic Human Orphan (ECHO) virus, were chosen for this study simulating important foodborne viruses (human noroviruses (NoV) and human enteroviruses, resp.). The model viruses were exposed to different solutions of D,L-lactic acid (0.1-0.4% w/w, pH 6.0-3.2), of sodium chloride (2-20%, w/v) and of sodium nitrite (100, 150 and 200 ppm) at 4 and 20 °C for a maximum of 7 days. Different results were obtained for the two viruses. ECHO virus was highly stable against D,L-lactic acid and sodium chloride when tested under all conditions. On the contrary, FCV showed less stability but was not effectively inactivated when exposed to low acid and high salt conditions at refrigeration temperatures (4 °C). FCV titers decreased more markedly at 20 °C than 4 °C in all experiments. Sodium nitrite did not show any effect on the inactivation of both viruses. The results indicate that acidification, salting or curing maybe insufficient for effective inactivation of foodborne viruses such as NoV or human enteroviruses during food processing. Thus, application of higher temperature during fermentation and ripening processes maybe more effective toward the inactivation kinetics of less stable viruses. Nevertheless, more studies are needed to examine the antiviral properties of these preserving agents on virus survival and inactivation kinetics in the complex food matrix.

  1. Cerebroprotective effect of isolated harmine alkaloids extracts of seeds of Peganum harmala L. on sodium nitrite-induced hypoxia and ethanol-induced neurodegeneration in young mice.

    PubMed

    Biradar, S M; Joshi, Hanumanthachar; Tarak, K C

    2013-12-01

    The aim of the study was to isolate the harmine alkaloids from the seeds of Peganum harmala (TAPH) and its cerebroprotective effect on cognitive deficit mice. The tested doses of TAPH were screened for Sodium nitrite induced hypoxia and Ethanol induced neurodegeneration using behavioral models. The TAPH was found to be non-neurotoxic and Psychoactive by preventing the motor impairment and increasing the locomotion activity of animals in Rota rod and Actophotometer respectively. TAPH (5, 2.5 and 1.25 mg kg(-1) p.o.) significantly (p < 0.001) protected the Sodium nitrite induced memory impairment by decreasing the time require to find the water bottle in special water bottle case model. In Elevated Plus Maze (EPM) and Passive Shock Avoidance paradigm (PSA) the TAPH shown improved acquisition and retention memory significantly (p < 0.001) by decreasing the Transverse Latency Time (TLT) and increasing the Step Down Latency (SDL), respectively in dose dependent manner. The results were well supported by biochemical parameters, by inhibiting the Acetylcholinestrase (p < 0.01) activity, increasing the GSH (p < 0.001) level and decreasing the TBARS (p < 0.001) level of whole brain. Moreover TAPH has shown the significant Monoamine oxidase-A (MAO-A) inhibition action (p < 0.001), hence it reduces the metabolism of epinephrine, 5-HT and other monoamines and enhances the action of these neurotransmitters indirectly; this adrenergic system plays an important role in learning and memory. Further, TAPH (5 mg kg(-1)) protect the DNA fragmentation of frontotemporal cortex of the brain from hypoxic effect induced by Sodium nitrite in Gel Electrophoresis studies. The results were comparable to their respective standards. Hence, harmine alkaloids are potential enough to utilize in the management of Neurodegenerative disorders of the type Alzheimer's diseases.

  2. Sodium nitrite-induced oxidative stress causes membrane damage, protein oxidation, lipid peroxidation and alters major metabolic pathways in human erythrocytes.

    PubMed

    Ansari, Fariheen Aisha; Ali, Shaikh Nisar; Mahmood, Riaz

    2015-10-01

    Nitrite salts are present as contaminants in drinking water and in the food and feed chain. In this work, the effect of sodium nitrite (NaNO2) on human erythrocytes was studied under in vitro conditions. Incubation of erythrocytes with 0.1-10.0 mM NaNO2 at 37 °C for 30 min resulted in dose dependent decrease in the levels of reduced glutathione, total sulfhydryl and amino groups. It was accompanied by increase in hemoglobin oxidation and aggregation, lipid peroxidation, protein oxidation and hydrogen peroxide levels suggesting the induction of oxidative stress. Activities of all major erythrocyte antioxidant defense enzymes were decreased in NaNO2-treated erythrocytes. The activities of enzymes of glycolytic and pentose phosphate pathways were also compromised. However, there was a significant increase in acid phosphatase and also AMP deaminase, a marker of erythrocyte oxidative stress. Thus, the major metabolic pathways of cell were altered. Erythrocyte membrane damage was suggested by lowered activities of membrane bound enzymes and confirmed by electron microscopic images. These results show that NaNO2-induced oxidative stress causes hemoglobin denaturation and aggregation, weakens the cellular antioxidant defense mechanism, damages the cell membrane and also perturbs normal energy metabolism in erythrocytes. This nitrite-induced damage can reduce erythrocyte life span in the blood.

  3. Acute hemodynamic effects of inhaled sodium nitrite in pulmonary hypertension associated with heart failure with preserved ejection fraction

    PubMed Central

    Simon, Marc A.; Vanderpool, Rebecca R.; Nouraie, Mehdi; Bachman, Timothy N.; White, Pamela M.; Sugahara, Masataka; Gorcsan, John; Parsley, Ed L.; Gladwin, Mark T.

    2016-01-01

    BACKGROUND. Pulmonary hypertension (PH) is associated with poor outcomes, yet specific treatments only exist for a small subset of patients. The most common form of PH is that associated with left heart disease (Group 2), for which there is no approved therapy. Nitrite has shown efficacy in preclinical animal models of Group 1 and 2 PH, as well as in patients with left heart failure with preserved ejection fraction (HFpEF). We evaluated the safety and efficacy of a potentially novel inhaled formulation of nitrite in PH-HFpEF patients as compared with Group 1 and 3 PH. METHODS. Cardiopulmonary hemodynamics were recorded after acute administration of inhaled nitrite at 2 doses, 45 and 90 mg. Safety endpoints included change in systemic blood pressure and methemoglobin levels. Responses were also compared with those administered inhaled nitric oxide. RESULTS. Thirty-six patients were enrolled (10 PH-HFpEF, 20 Group 1 pulmonary arterial hypertension patients on background PH-specific therapy, and 6 Group 3 PH). Drug administration was well tolerated. Nitrite inhalation significantly lowered pulmonary, right atrial, and pulmonary capillary wedge pressures, most pronounced in patients with PH-HFpEF. There was a modest decrease in cardiac output and systemic blood pressure. Pulmonary vascular resistance decreased only in Group 3 PH patients. There was substantial increase in pulmonary artery compliance, most pronounced in patients with PH-HFpEF. CONCLUSIONS. Inhaled nitrite is safe in PH patients and may be efficacious in PH-HFpEF and Group 3 PH primarily via improvements in left and right ventricular filling pressures and pulmonary artery compliance. The lack of change in pulmonary vascular resistance likely may limit efficacy for Group 1 patients. TRIAL REGISTRATION. ClinicalTrials.gov NCT01431313 FUNDING. This work was supported in part by the NIH grants P01HL103455 (to MAS and MTG), R01HL098032 (to MTG), and R01HL096973 (to MTG), and Mast Therapeutics, Inc. PMID

  4. Impact of organic load on Escherichia coli O157:H7 survival during pilot-scale processing of iceberg lettuce with acidified sodium hypochlorite.

    PubMed

    Davidson, Gordon R; Kaminski, Chelsea N; Ryser, Elliot T

    2014-10-01

    Chemical sanitizers are routinely used during commercial flume washing of fresh-cut leafy greens to minimize cross-contamination from the water. This study assessed the efficacy of three chlorine treatments against Escherichia coli O157:H7 on iceberg lettuce, in wash water, and on surfaces of a pilot-scale processing line using flume water containing various organic loads. Iceberg lettuce (5.4 kg) was inoculated to contain 10(6) CFU/g of a 4-strain cocktail of nontoxigenic, green fluorescent protein-labeled, ampicillin-resistant E. coli O157:H7 and held for 24 h at 4°C before processing. Lettuce was shredded using a Urschel TransSlicer, step conveyed to a flume tank, washed for 90 s using water alone or one of three different sanitizing treatments (50 ppm of total chlorine either alone or acidified to pH 6.5 with citric acid or T-128) in water containing organic loads of 0, 2.5, 5, or 10% (wt/vol) blended iceberg lettuce, and then dried using a shaker table and centrifugal dryer. Next, three 5.4-kg batches of uninoculated iceberg lettuce were processed identically. Various product (25 g), water (50 ml), and equipment surface swab (100 cm(2)) samples were homogenized in neutralizing buffer, diluted appropriately, and plated on tryptic soy agar containing 0.6% (wt/vol) yeast extract and 100 ppm of ampicillin without prior 0.45- m m membrane filtration to quantify E. coli O157:H7. Organic load negatively impacted the efficacy of all three chlorine treatments (P < 0.05) at the end of processing, with typical E. coli O157:H7 reductions of >5 and 0.9 to 3.7 log CFU/ml for organic loads of 0 and 10%, respectively. Organic load rarely had a significant impact (P < 0.05) on the efficacy of chlorine, chlorine plus citric acid, or chlorine plus T-128 against E. coli O157:H7 on iceberg lettuce. Reduced sanitizer efficacy generally corresponded to changes in total solids, chemical oxygen demand, turbidity, and maximum filterable volume, indicating that these tests may be

  5. A dissimilatory nitrite reductase in Paracoccus halodenitrificans

    NASA Technical Reports Server (NTRS)

    Grant, M. A.; Hochstein, L. I.

    1984-01-01

    Paracoccus halodenitrificans produced a membrane-associated nitrite reductase. Spectrophotometric analysis showed it to be associated with a cd-cytochrome and located on the inner side of the cytoplasmic membrane. When supplied with nitrite, membrane preparations produced nitrous oxide and nitric oxide in different ratios depending on the electron donor employed. The nitrite reductase was maximally active at relatively low concentrations of sodium chloride and remained attached to the membranes at 100 mM sodium chloride.

  6. The curing agent sodium nitrite, used in the production of fermented sausages, is less inhibiting to the bacteriocin-producing meat starter culture Lactobacillus curvatus LTH 1174 under anaerobic conditions.

    PubMed

    Verluyten, Jurgen; Messens, Winy; De Vuyst, Luc

    2003-07-01

    Curvacin A is a listericidal bacteriocin produced by Lactobacillus curvatus LTH 1174, a strain isolated from fermented sausage. The response of this strain to an added curing agent (sodium nitrite) in terms of cell growth and bacteriocin production was investigated in vitro by laboratory fermentations with modified MRS broth. The strain was highly sensitive to nitrite; even a concentration of 10 ppm of curing agent inhibited its growth and both volumetric and specific bacteriocin production. A meat simulation medium containing 5 ppm of sodium nitrite was tested to investigate the influence of the gas phase on the growth and bacteriocin production of L. curvatus LTH 1174. Aerating the culture during growth had no effect on biomass formation, but the oxidative stress caused a higher level of specific bacteriocin production and led to a metabolic shift toward acetic acid production. Anaerobic conditions, on the other hand, led to an increased biomass concentration and less growth inhibition. Also, higher maximum volumetric bacteriocin activities and a higher level of specific bacteriocin production were obtained in the presence of sodium nitrite than in fermentations under aerobic conditions or standard conditions of air supply. These results indicate that the inhibitory effect of the curing agent is at least partially masked under anaerobic conditions.

  7. Gastric S-nitrosothiol formation drives the antihypertensive effects of oral sodium nitrite and nitrate in a rat model of renovascular hypertension.

    PubMed

    Pinheiro, Lucas C; Amaral, Jefferson H; Ferreira, Graziele C; Portella, Rafael L; Ceron, Carla S; Montenegro, Marcelo F; Toledo, Jose Carlos; Tanus-Santos, Jose E

    2015-10-01

    Many effects of nitrite and nitrate are attributed to increased circulating concentrations of nitrite, ultimately converted into nitric oxide (NO(•)) in the circulation or in tissues by mechanisms associated with nitrite reductase activity. However, nitrite generates NO(•) , nitrous anhydride, and other nitrosating species at low pH, and these reactions promote S-nitrosothiol formation when nitrites are in the stomach. We hypothesized that the antihypertensive effects of orally administered nitrite or nitrate involve the formation of S-nitrosothiols, and that those effects depend on gastric pH. The chronic effects of oral nitrite or nitrate were studied in two-kidney, one-clip (2K1C) hypertensive rats treated with omeprazole (or vehicle). Oral nitrite lowered blood pressure and increased plasma S-nitrosothiol concentrations independently of circulating nitrite levels. Increasing gastric pH with omeprazole did not affect the increases in plasma nitrite and nitrate levels found after treatment with nitrite. However, treatment with omeprazole severely attenuated the increases in plasma S-nitrosothiol concentrations and completely blunted the antihypertensive effects of nitrite. Confirming these findings, very similar results were found with oral nitrate. To further confirm the role of gastric S-nitrosothiol formation, we studied the effects of oral nitrite in hypertensive rats treated with the glutathione synthase inhibitor buthionine sulfoximine (BSO) to induce partial thiol depletion. BSO treatment attenuated the increases in S-nitrosothiol concentrations and antihypertensive effects of oral nitrite. These data show that gastric S-nitrosothiol formation drives the antihypertensive effects of oral nitrite or nitrate and has major implications, particularly to patients taking proton pump inhibitors.

  8. Application of In-Line Mid-Infrared (MIR) Spectroscopy Coupled with Calorimetry for the Determination of the Molar Enthalpy of Reaction between Ammonium Chloride and Sodium Nitrite.

    PubMed

    Kartnaller, Vinicius; Mariano, Danielly C O; Cajaiba, João

    2016-03-01

    The reaction between ammonium chloride and sodium nitrite has been known for its application as a source of heat because of its large enthalpy of reaction, for which it has been used by the oil industry. There have been no known calorimetric studies for the experimental determination of its molar enthalpy of reaction, which is necessary in order to predict the limits achieved for up-scale applications. Attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) and reaction calorimetry were used to determine this value by using a simple methodology. Both techniques were used concomitantly as a source of information regarding the time-dependent moles converted (Δn) and the amount of exchanged heat (ΔH). The molar enthalpy of reaction was calculated to be -74 ± 4 kcal mol(-1). The percentage between the confidence interval and the calculated value was 5.4%, which shows that the methodology was precise. After the determination of the molar enthalpy of reaction, it was proved that the ATR FT-IR alone was able to be used as a substitute for the reaction calorimetry technique, in which the IR signal is converted to the heat information, presenting as an easier technique for the monitoring of the heat released by this system for future applications.

  9. New composite nitrite-free and low-nitrite meat-curing systems using natural colorants

    PubMed Central

    Eskandari, Mohammad H; Hosseinpour, Sara; Mesbahi, GholamReza; Shekarforoush, Shahram

    2013-01-01

    Nitrite-free and low-nitrite meat-curing systems were developed to eliminate or reduce nitrite in frankfurter-type sausages. Different composite meat-curing mixtures were formulated using cochineal and paprika as natural colorants, sodium hypophosphite (SHP) as antimicrobial agent, butylated hydroxyanisole (BHA) as antioxidant and sodium nitrite. The treatment, which contained 0.015% cochineal, most closely resembled the 120 ppm NaNO2 in its ability to create cured-meat color. BHA was found to be a strong antioxidant at the 30 ppm level in cooked sausages during refrigerated storage for 5 weeks. All treatments containing 40 ppm sodium nitrite were successful in replicating sensory attributes of frankfurter samples. Our findings support the use of SHP as possible antibotulinal agent in nitrite-free meat-curing systems. PMID:24804046

  10. 7 CFR 58.720 - Acidifying agents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Material § 58.720 Acidifying agents. Acidifying agents if used shall be those permitted by the Food...

  11. 7 CFR 58.720 - Acidifying agents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Material § 58.720 Acidifying agents. Acidifying agents if used shall be those permitted by the Food...

  12. 7 CFR 58.720 - Acidifying agents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Material § 58.720 Acidifying agents. Acidifying agents if used shall be those permitted by the Food...

  13. 7 CFR 58.720 - Acidifying agents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Material § 58.720 Acidifying agents. Acidifying agents if used shall be those permitted by the Food...

  14. 7 CFR 58.720 - Acidifying agents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Material § 58.720 Acidifying agents. Acidifying agents if used shall be those permitted by the Food...

  15. 21 CFR 131.111 - Acidified milk.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Acidified milk. 131.111 Section 131.111 Food and... CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.111 Acidified milk. (a) Description. Acidified milk is the food produced by souring one or more of the optional dairy...

  16. 21 CFR 131.111 - Acidified milk.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Acidified milk. 131.111 Section 131.111 Food and... CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.111 Acidified milk. (a) Description. Acidified milk is the food produced by souring one or more of the optional dairy...

  17. 21 CFR 131.111 - Acidified milk.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Acidified milk. 131.111 Section 131.111 Food and... CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.111 Acidified milk. (a) Description. Acidified milk is the food produced by souring one or more of the optional dairy...

  18. Molecular cloning, characterization and gene expression of murrel CXC chemokine receptor 3a against sodium nitrite acute toxicity and microbial pathogens.

    PubMed

    Bhatt, Prasanth; Chaurasia, Mukesh Kumar; Palanisamy, Rajesh; Kumaresan, Venkatesh; Arasu, Abirami; Sathyamoorthi, Akila; Gnanam, Annie J; Kasi, Marimuthu; Pasupuleti, Mukesh; Ramaswamy, Harikrishnan; Arockiaraj, Jesu

    2014-08-01

    CXCR3 is a CXC chemokine receptor 3 which binds to CXC ligand 4 (CXCL4), 9, 10 and 11. CXC chemokine receptor 3a (CXCR3a) is one of the splice variants of CXCR3. It plays crucial role in defense and other physiological processes. In this study, we report the molecular cloning, characterization and gene expression of CXCR3a from striped murrel Channa striatus (Cs). The full length CsCXCR3a cDNA sequence was obtained from the constructed cDNA library of striped murrel by cloning and sequencing using an internal sequencing primer. The full length sequence is 1425 nucleotides in length including an open reading frame of 1086 nucleotides which is encoded with a polypeptide of 361 amino acids (mol. wt. 40 kDa). CsCXCR3a domain analysis showed that the protein contains a G protein coupled receptor between 55 and 305 along with its family signature at 129-145. The transmembrane prediction analysis showed that CsCXCR3a protein contains 7 transmembrane helical regions at 34-65, 80-106, 113-146, 154-181, 208-242, 249-278 and 284-308. The 'DRY' motif from CsCXCR3a protein sequence at (140)Asp-(141)Arg-(142)Tyr which is responsible for G-protein binding is also highly conserved with CXCR3 from other species. Phylogenetic tree showed that the CXC chemokine receptors 3, 4, 5 and 6, each formed a separate clade, but 1 and 2 were clustered together, which may be due to the high similarity between these receptors. The predicted 3D structure revealed cysteine residues, which are responsible for 'CXC' motif at 116 and 198. The CsCXR3a transcript was found to be high in kidney, further its expression was up-regulated by sodium nitrite acute toxicity exposure, fungal, bacterial and poly I:C challenges. Overall, these results supported the active involvement of CsCXCR3a in inflammatory process of striped murrel during infection. However, further study is necessary to explore the striped murrel chemokine signaling pathways and their roles in defense system.

  19. Boletus edulis Nitrite Reductase Reduces Nitrite Content of Pickles and Mitigates Intoxication in Nitrite-intoxicated Mice

    PubMed Central

    Zhang, Weiwei; Tian, Guoting; Feng, Shanshan; Wong, Jack Ho; Zhao, Yongchang; Chen, Xiao; Wang, Hexiang; Ng, Tzi Bun

    2015-01-01

    Pickles are popular in China and exhibits health-promoting effects. However, nitrite produced during fermentation adversely affects health due to formation of methemoglobin and conversion to carcinogenic nitrosamine. Fruiting bodies of the mushroom Boletus edulis were capable of inhibiting nitrite production during pickle fermentation. A 90-kDa nitrite reductase (NiR), demonstrating peptide sequence homology to fungal nitrite reductase, was isolated from B. edulis fruiting bodies. The optimum temperature and pH of the enzyme was 45 °C and 6.8, respectively. B. edulis NiR was capable of prolonging the lifespan of nitrite-intoxicated mice, indicating that it had the action of an antidote. The enzyme could also eliminate nitrite from blood after intragastric administration of sodium nitrite, and after packaging into capsule, this nitrite-eliminating activity could persist for at least 120 minutes thus avoiding immediate gastric degradation. B. edulis NiR represents the first nitrite reductase purified from mushrooms and may facilitate subsequent applications. PMID:26446494

  20. Boletus edulis Nitrite Reductase Reduces Nitrite Content of Pickles and Mitigates Intoxication in Nitrite-intoxicated Mice.

    PubMed

    Zhang, Weiwei; Tian, Guoting; Feng, Shanshan; Wong, Jack Ho; Zhao, Yongchang; Chen, Xiao; Wang, Hexiang; Ng, Tzi Bun

    2015-10-08

    Pickles are popular in China and exhibits health-promoting effects. However, nitrite produced during fermentation adversely affects health due to formation of methemoglobin and conversion to carcinogenic nitrosamine. Fruiting bodies of the mushroom Boletus edulis were capable of inhibiting nitrite production during pickle fermentation. A 90-kDa nitrite reductase (NiR), demonstrating peptide sequence homology to fungal nitrite reductase, was isolated from B. edulis fruiting bodies. The optimum temperature and pH of the enzyme was 45 °C and 6.8, respectively. B. edulis NiR was capable of prolonging the lifespan of nitrite-intoxicated mice, indicating that it had the action of an antidote. The enzyme could also eliminate nitrite from blood after intragastric administration of sodium nitrite, and after packaging into capsule, this nitrite-eliminating activity could persist for at least 120 minutes thus avoiding immediate gastric degradation. B. edulis NiR represents the first nitrite reductase purified from mushrooms and may facilitate subsequent applications.

  1. 21 CFR 108.25 - Acidified foods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Acidified foods. 108.25 Section 108.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... With an Emergency Permit § 108.25 Acidified foods. (a) Inadequate or improper manufacture,...

  2. 21 CFR 108.25 - Acidified foods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Acidified foods. 108.25 Section 108.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... With an Emergency Permit § 108.25 Acidified foods. (a) Inadequate or improper manufacture,...

  3. 21 CFR 108.25 - Acidified foods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Acidified foods. 108.25 Section 108.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... With an Emergency Permit § 108.25 Acidified foods. (a) Inadequate or improper manufacture,...

  4. Enhancing nitrite inhibition of Clostridium botulinum with isoascorbate in perishable canned cured meat.

    PubMed Central

    Tompkin, R B; Christiansen, L N; Shaparis, A B

    1978-01-01

    Addition of sodium isoascorbate to the formulation for perishable canned comminuted cured meat markedly enhanced the efficacy of nitrite against Clostridium botulinum. This effect was reproducible through a series of three tests. In one test it was found that the initial addition of 50 microgram of sodium nitrite per g plus isoascorbate was as effective as 156 microgram of sodium nitrite per g alone. PMID:341810

  5. Radiation preservation of low nitrite bacon

    NASA Astrophysics Data System (ADS)

    Singh, Harwant

    Sodium nitrite, a key ingredient of the mix used to cure bacon and other meats, promotes and fixes bacon's characteristic pink color, inhibits lipid peroxidation and prevents growth of microorganisms, particularly Clostridium botulinum spores. Unfortunately, nitrite leads to the formation of carcinogenic nitrosamines in bacon. This has led to a search for alternatives to the use of nitrite. Irradiation with reduced level of nitrite is a promising alternative. Radurization of bacon containing 20 to 40 mg/kg of nitrite in evacuated packages, irradiated and stored at 4°C, gives a product with good organoleptic qualities and extended shelf life of ⩾ 90 days, as opposed to ˜ 30 days for the conventionally treated bacon. Radappertization of bacon containing 20 mg/kg of nitrite at a dose of about 30 kGy, irradiated at temperature of -20° or lower in evacuated packages, results in a product that is shelf stable at room temperature for months to years. It has organoleptic qualities comparable to commercial bacon in terms of color, flavor, odor and texture. Irradiation also reduces the nitrite and preformed nitrosamines present in bacon. Various aspects of preservation of bacon are reviewed in this report with emphasis on radiation processing.

  6. Nitrate, Nitrite, and nitroso compounds in foods

    SciTech Connect

    Hotchkiss, J.H.; Cassens, R.G.

    1987-04-01

    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 liver failure. The nitrosamine resulted from the reaction between dimethylamine contained in the fish and the added nitrite. Because nitrite is an important and widely used human food additive, particularly in the curing of meats, poultry, and fish, research was undertaken by several groups around the world to investigate the occurrence of these compounds in human foods.

  7. 21 CFR 131.111 - Acidified milk.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.111 Acidified milk. (a... ingredients. Cream, milk, partially skimmed milk, or skim milk, used alone or in combination. (d)...

  8. Inorganic Nitrite Therapy: Historical perspective and future directions

    PubMed Central

    Kevil, Christopher G.; Kolluru, Gopi K.; Pattillo, Christopher B.; Giordano, Tony

    2015-01-01

    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 that 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 pro-drug. 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 of nitrite based therapies. PMID:21619929

  9. Nitrite in organ protection

    PubMed Central

    Rassaf, Tienush; Ferdinandy, Peter; Schulz, Rainer

    2014-01-01

    In the last decade, the nitrate-nitrite-nitric oxide pathway has emerged to therapeutical importance. Modulation of endogenous nitrate and nitrite levels with the subsequent S-nitros(yl)ation of the downstream signalling cascade open the way for novel cytoprotective strategies. In the following, we summarize the actual literature and give a short overview on the potential of nitrite in organ protection. PMID:23826831

  10. Characterization and inhibition of nitrite uptake in shortnose sturgeon fingerlings

    USGS Publications Warehouse

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

    1999-01-01

    Efforts are underway to culture the endangered shortnose sturgeon Acipenser brevirostrum for possible reintroduction. As part of a larger project to develop culture techniques for this species, the uptake of nitrite was evaluated in fingerlings (16.5 ?? 4.85 g; mean ?? SD). Plasma nitrite concentrations increased significantly with exposure time (0-5 d) and dose (0-4 mg nitrite-N/L). Shortnose sturgeon fingerlings were able to concentrate nitrite in their plasma to more than 63 times the environmental concentration. Chloride, as either sodium chloride or calcium chloride, partially inhibited nitrite uptake. However, calcium chloride was a better inhibitor. After previous exposure (2 d at 2.13 ?? 0.080 mg nitrite-N/L) plasma nitrite-N decreased from 165.5 to 36.7 mg/L during a 3-d simultaneous exposure to 2.13 ?? 0.080 mg nitrite-N/L and treatment with 40 mg chloride/L as calcium chloride. The addition of calcium chloride to the water appeared to be an effective means of preventing nitrite uptake and treating nitrite toxicity in hatchery-reared shortnose sturgeon fingerlings.

  11. Microbiological Spoilage of Acidified Specialty Products

    NASA Astrophysics Data System (ADS)

    Sperber, William H.

    Acidified specialty products or condiments are among the most microbiologically stable and safe food products. Often formulated, packaged, and distributed without heat treatments, they are microbiologically stable indefinitely at ambient temperatures in unopened containers. The packaged, acidified products are often intended for multiple uses, exposing them at the points of consumption to numerous opportunities for contamination with microorganisms. Nonetheless, they remain resistant to microbiological spoilage for many months, often under refrigerated conditions that are used to retard chemical reactions, flavor changes, and yeast growth.

  12. 21 CFR 108.25 - Acidified foods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN..., or packing of acidified foods may result in the distribution in interstate commerce of processed... after these foods have entered into interstate commerce. The Commissioner of Food and Drugs...

  13. Chemical behavior of acidified chromium (3) solutions

    SciTech Connect

    Terman, D.K.

    1981-05-01

    A unique energy-storage system has been developed at NASA's Lewis Research Center called REDOX. This NASA-REDOX system is an electrochemical storage device that utilized the oxidation and reduction of two fully soluble redox couples for charging and discharging. The redox couples now being investigated are acidified chloride solutions of chromium (Cr(+2)/Cr(+3)) and iron (Fe(+2)/Fe(+3)).

  14. Color Developing Capacity of Plasma-treated Water as a Source of Nitrite for Meat Curing

    PubMed Central

    Jung, Samooel; Kim, Hyun Joo; Park, Sanghoo; Choe, Jun Ho; Jeon, Hee-Joon; Choe, Wonho

    2015-01-01

    The interaction of plasma with liquid generates nitrogen species including nitrite (NO−2). Therefore, the color developing capacity of plasma-treated water (PTW) as a nitrite source for meat curing was investigated in this study. PTW, which is generated by surface dielectric barrier discharge in air, and the increase of plasma treatment time resulted in increase of nitrite concentration in PTW. The PTW used in this study contains 46 ppm nitrite after plasma treatment for 30 min. To evaluate the effect of PTW on the cured meat color, meat batters were prepared under three different conditions (control, non-cured meat batter; PTW, meat batter cured with PTW; Sodium nitrite, meat batter cured with sodium nitrite). The meat batters were vacuum-packaged and cooked in a water-bath at 80℃ for 30 min. The typical color of cured meat developed in cooked meat batter treated with sodium nitrite or PTW. The lightness (L*) and yellowness (b*) values were similar in all conditions, whereas, the redness (a*) values of cooked meat batter with PTW and sodium nitrite (p<0.05) were significantly higher than the control. These data indicate that PTW can be used as a nitrite source in the curing process of meat without addition of other nitrite sources. PMID:26761900

  15. Nitrite Modulates Bacterial Antibiotic Susceptibility and Biofilm Formation in Association with Airway Epithelial Cells

    PubMed Central

    Zemke, Anna C; Shiva, Sruti; Burn, Jane L.; Moskowitz, Samuel M.; Pilewski, Joseph M.; Gladwin, Mark T.; Bomberger, Jennifer M.

    2014-01-01

    Pseudomonas aeruginosa is the major pathogenic bacteria in cystic fibrosis and other forms of bronchiectasis. Growth in antibiotic resistant biofilms contributes to the virulence of this organism. Sodium nitrite has antimicrobial properties and has been tolerated as a nebulized compound at high concentrations in human subjects with pulmonary hypertension; however, its effects have not been evaluated on biotic biofilms or in combination with other clinically useful antibiotics. We grew P. aeruginosa on the apical surface of primary human airway epithelial cells to test the efficacy of sodium nitrite against biotic biofilms. Nitrite alone prevented 99% of biofilm growth. We then identified significant cooperative interactions between nitrite and polymyxins. For P. aeruginosa growing on primary CF airway cells, combining nitrite and colistimethate resulted in an additional log of bacterial inhibition compared to treating with either agent alone. Nitrite and colistimethate additively inhibited oxygen consumption by P. aeruginosa. Surprisingly, while the antimicrobial effects of nitrite in planktonic, aerated cultures are nitric oxide (NO) dependent, antimicrobial effects in other growth conditions are not. The inhibitory effect of nitrite on bacterial oxygen consumption and biofilm growth did not require NO as an intermediate as chemically scavenging NO did not block growth inhibition. These data suggest an NO-radical independent nitrosative or oxidative inhibition of respiration. The combination of nebulized sodium nitrite and colistimethate may provide a novel therapy for chronic P. aeruginosa airway infections, because sodium nitrite, unlike other antibiotic respiratory chain ‘poisons’, can be safely nebulized at high concentration in humans. PMID:25229185

  16. 21 CFR 172.824 - Sodium mono- and dimethyl naphthalene sulfonates.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... sodium nitrite at a level not in excess of 0.1 percent by weight thereof for authorized uses in cured... additive and its label or labeling shall bear adequate directions for use. (2) Sodium nitrite produced...

  17. 21 CFR 172.824 - Sodium mono- and dimethyl naphthalene sulfonates.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... sodium nitrite at a level not in excess of 0.1 percent by weight thereof for authorized uses in cured... additive and its label or labeling shall bear adequate directions for use. (2) Sodium nitrite produced...

  18. 21 CFR 131.162 - Acidified sour cream.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Acidified sour cream. 131.162 Section 131.162 Food... HUMAN CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.162 Acidified sour cream. (a) Description. Acidified sour cream results from the souring of pasteurized...

  19. Performance of Denitrifying Microbial Fuel Cell with Biocathode over Nitrite

    PubMed Central

    Zhao, Huimin; Zhao, Jianqiang; Li, Fenghai; Li, Xiaoling

    2016-01-01

    Microbial fuel cell (MFC) with nitrite as an electron acceptor in cathode provided a new technology for nitrogen removal and electricity production simultaneously. The influences of influent nitrite concentration and external resistance on the performance of denitrifying MFC were investigated. The optimal effectiveness were obtained with the maximum total nitrogen (TN) removal rate of 54.80 ± 0.01 g m−3 d−1. It would be rather desirable for the TN removal than electricity generation at lower external resistance. Denaturing gradient gel electrophoresis suggested that Proteobacteria was the predominant phylum, accounting for 35.72%. Thiobacillus and Afipia might benefit to nitrite removal. The presence of nitrifying Devosia indicated that nitrite was oxidized to nitrate via a biochemical mechanism in the cathode. Ignavibacterium and Anaerolineaceae was found in the cathode as a heterotrophic bacterium with sodium acetate as substrate, which illustrated that sodium acetate in anode was likely permeated through proton exchange membrane to the cathode. PMID:27047462

  20. Electrochemical Evaluation of Stainless Steels in Acidified Sodium Chloride Solutions

    NASA Technical Reports Server (NTRS)

    Calle, L. M.; MacDowell, L. G.; Vinje, R. D.

    2004-01-01

    This paper presents the results of an investigation in which several 300-series stainless steels (SS): AISI S30403 SS (UNS S30403), AISI 316L SS (UNS S31603), and AISI 317L SS (LINS S31703), as well as highly-alloyed: SS 254-SMO (UNS S32154), AL-6XN (N08367) and AL29-4C (UNS S44735), were evaluated using DC electrochemical techniques in three different electrolyte solutions. The solutions consisted of neutral 3.55% NaCl, 3.55% NaCl in 0.1N HCl, and 3.55% NaCl in 1.0N HCl. These solutions were chosen to simulate environments that are less, similar, and more aggressive, respectively, than the conditions at the Space Shuttle launch pads. The electrochemical test results were compared to atmospheric exposure data and evaluated for their ability to predict the long-term corrosion performance of the subject alloys. The electrochemical measurements for the six alloys indicated that the higher-alloyed SS 254-SMO, AL29-4C, and AL-6XN exhibited significantly higher resistance to localized corrosion than the 300-series SS. There was a correlation between the corrosion performance of the alloys during a two-year atmospheric exposure and the corrosion rates calculated from electrochemical (polarization resistance) measurements.

  1. 21 CFR 173.325 - Acidified sodium chlorite solutions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) with any generally recognized as safe (GRAS) acid. (b)(1) The additive is used as an antimicrobial... chlorite concentrations between 500 and 1,200 parts per million (ppm), in combination with any GRAS acid at... ppm, in combination with any GRAS acid at levels sufficient to achieve a solution pH of 2.8 to 3.2....

  2. Mechanisms of Nitrite Bioactivation

    PubMed Central

    Kim-Shapiro, Daniel B.; Gladwin, Mark T.

    2014-01-01

    It is now accepted that the anion nitrite, once considered an inert oxidation product of nitric oxide (NO), contributes to hypoxic vasodilation, physiological blood pressure control, and redox signaling. As such, its application in therapeutics is being actively testing in pre-clinical models and in human phase I–II clinical trials. Major pathways for nitrite bioactivation involve its reduction to NO by members of the hemoglobin or molybdopterin family of proteins, or catalyzed dysproportionation. These conversions occur preferentially under hypoxic and acidic conditions. A number of enzymatic systems reduce nitrite to NO and their activity and importance are defined by oxygen tension, specific organ system and allosteric and redox effectors. In this work, we review different proposed mechanisms of nitrite bioactivation, focusing on analysis of kinetics and experimental evidence for the relevance of each mechanism under different conditions. PMID:24315961

  3. Determination of nitrite via reaction with pyridine-4-carboxylic acid hydrazide

    SciTech Connect

    Verma, K.K.; Tyagi, P.

    1985-06-01

    Nitrite is determined by its reaction with a measured but excessive amount of pyridine-4-carboxylic acid hydrazide in acid medium (when the two substances react in a 1:1 molar ratio) and evaluation of the surplus hydrazide by titration with chloramine-T in the presence of acidified potassium bromide, the end-point being shown by the decolorization of the methyl red indicator. Nitrate, copper(II), mercury(II), etc. are found not to interfere, and the determination of nitrite in the presence of diazotized aromatic amines is demonstrated. 11 references, 2 tables.

  4. Increased consumption and vasodilatory effect of nitrite during exercise

    PubMed Central

    Hon, Yuen Yi; Lin, Elaina E.; Tian, Xin; Yang, Yang; Sun, He; Swenson, Erik R.; Taveira-Dasilva, Angelo M.; Gladwin, Mark T.

    2015-01-01

    This study investigated the effects of aerobic-to-anaerobic exercise on nitrite stores in the human circulation and evaluated the effects of systemic nitrite infusion on aerobic and anaerobic exercise capacity and hemodynamics. Six healthy volunteers were randomized to receive sodium nitrite or saline for 70 min in two separate occasions in an exercise study. Subjects cycled on an upright electronically braked cycle ergometer 30 min into the infusion according to a ramp protocol designed to attain exhaustion in 10 min. They were allowed to recover for 30 min thereafter. The changes of whole blood nitrite concentrations over the 70-min study period were analyzed by pharmacokinetic modeling. Longitudinal measurements of hemodynamic and clinical variables were analyzed by fitting nonparametric regression spline models. During exercise, nitrite consumption/elimination rate was increased by ∼137%. Cardiac output (CO), mean arterial pressure (MAP), and pulmonary artery pressure (PAP) were increased, but smaller elevation of MAP and larger increases of CO and PAP were found during nitrite infusion compared with placebo control. The higher CO and lower MAP during nitrite infusion were likely attributed to vasodilation and a trend toward decrease in systemic vascular resistance. In contrast, there were no significant changes in mean pulmonary artery pressures and pulmonary vascular resistance. These findings, together with the increased consumption of nitrite and production of iron-nitrosyl-hemoglobin during exercise, support the notion of nitrite conversion to release NO resulting in systemic vasodilatation. However, at the dosing used in this protocol achieving micromolar plasma concentrations of nitrite, exercise capacity was not enhanced, as opposed to other reports using lower dosing. PMID:26684248

  5. Increased consumption and vasodilatory effect of nitrite during exercise.

    PubMed

    Hon, Yuen Yi; Lin, Elaina E; Tian, Xin; Yang, Yang; Sun, He; Swenson, Erik R; Taveira-Dasilva, Angelo M; Gladwin, Mark T; Machado, Roberto F

    2016-02-15

    This study investigated the effects of aerobic-to-anaerobic exercise on nitrite stores in the human circulation and evaluated the effects of systemic nitrite infusion on aerobic and anaerobic exercise capacity and hemodynamics. Six healthy volunteers were randomized to receive sodium nitrite or saline for 70 min in two separate occasions in an exercise study. Subjects cycled on an upright electronically braked cycle ergometer 30 min into the infusion according to a ramp protocol designed to attain exhaustion in 10 min. They were allowed to recover for 30 min thereafter. The changes of whole blood nitrite concentrations over the 70-min study period were analyzed by pharmacokinetic modeling. Longitudinal measurements of hemodynamic and clinical variables were analyzed by fitting nonparametric regression spline models. During exercise, nitrite consumption/elimination rate was increased by ∼137%. Cardiac output (CO), mean arterial pressure (MAP), and pulmonary artery pressure (PAP) were increased, but smaller elevation of MAP and larger increases of CO and PAP were found during nitrite infusion compared with placebo control. The higher CO and lower MAP during nitrite infusion were likely attributed to vasodilation and a trend toward decrease in systemic vascular resistance. In contrast, there were no significant changes in mean pulmonary artery pressures and pulmonary vascular resistance. These findings, together with the increased consumption of nitrite and production of iron-nitrosyl-hemoglobin during exercise, support the notion of nitrite conversion to release NO resulting in systemic vasodilatation. However, at the dosing used in this protocol achieving micromolar plasma concentrations of nitrite, exercise capacity was not enhanced, as opposed to other reports using lower dosing.

  6. Nitrates and Nitrites TNC Presentation

    EPA Pesticide Factsheets

    The Nitrates and Nitrites Presentation gives an overview of nitrates and nitrites in drinking water, why it is important to monitor them and what to do in cases where the results exceed the maximum contaminant level (MCL).

  7. Nitrates and nitrites in the treatment of ischemic cardiac disease.

    PubMed

    Nossaman, Vaughn E; Nossaman, Bobby D; Kadowitz, Philip J

    2010-01-01

    The organic nitrite, amyl of nitrite, was initially used as a therapeutic agent in the treatment of angina pectoris, but was replaced over a decade later by the organic nitrate, nitroglycerin (NTG), due to the ease of administration and longer duration of action. The administration of organic nitrate esters, such as NTG, continues to be used in the treatment of angina pectoris and heart failure since the birth of modern pharmacology. Their clinical effectiveness is due to vasodilator activity in large veins and arteries through an as yet unidentified method of delivering nitric oxide (NO), or a NO-like compound. The major drawback is the development of tolerance with NTG, and the duration and route of administration with amyl of nitrite. Although the nitrites are no longer used in the treatment of hypertension or ischemic heart disease, the nitrite anion has recently been discovered to possess novel pharmacologic actions, such as modulating hypoxic vasodilation, and providing cytoprotection in ischemia-reperfusion injury. Although the actions of these 2 similar chemical classes (nitrites and organic nitrates) have often been considered to be alike, we still do not understand their mechanism of action. Finally, the nitrite anion, either from sodium nitrite or an intermediate NTG form, may act as a storage form for NO and provide support for investigating the use of these agents in the treatment of ischemic cardiovascular states. We review what is presently known about the use of nitrates and nitrites including the historical, current, and potential uses of these agents, and their mechanisms of action.

  8. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  9. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  10. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  11. 21 CFR 172.170 - Sodium nitrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate. 172.170 Section 172.170 Food and... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  12. B-complex vitamins in cultured and acidified yogurt.

    PubMed

    Reddy, K P; Shahani, K M; Kulkarni, S M

    1976-02-01

    Studies were to determine the effect of various factors upon B-vitamin content of cultured yogurt and to compare the B-vitamin contents of cultured and direct acidified yogurt. Incubation of yogurt culture at 42 C for 3 h yielded maximum vitamin synthesis concurrent with optimal flavor and texture qualities. A method was standardized for the manufacture of direct acidified yogurt involving the use of Stabilac acidulant and nonfat dry milk, Carboxymethyl cellulose, gelatin, and Starite. Acidified yogurt showed a slightly higher content of certain B-vitamins than the cultured yogurt due to the contribution made by various food additives. Both cultured and acidified yogurt showed good keeping quality and freedom from microbial contaminants during storage at 5 C for 16 days. However, folic acid and vitamin B12 contents decreased 29 and 60% in cultured yogurt and 48 and 54% in acidified yogurt.

  13. Comparison Between Sodium Nitrite & Sodium Hydroxide Spray Accident

    SciTech Connect

    WILLIAMS, J.C.; HEY, B.E.

    2001-11-07

    The purpose of this analysis is to compare the consequences of an 8 molar NaNO2 spray leak to the Tank Farm Final Safety Analysis Report (FSAR) evaluation of sprays of up to 19 molar (50%) NaOH. Four conditions were evaluated. These are: a spray during transfers from a one-inch pipe, a spray resulting from a truck tank Crack, a spray resulting from a truck tank rupture, and a spray in the 204-AR Waste Unloading Facility.

  14. Low-dose intravenous nitrite improves hemodynamics in a canine model of acute pulmonary thromboembolism.

    PubMed

    Dias-Junior, Carlos A C; Gladwin, Mark T; Tanus-Santos, Jose E

    2006-12-15

    Acute pulmonary thomboembolism (APT)-induced pulmonary hypertension can be counteracted by activating the nitric oxide (NO)-cGMP pathway. Recent studies have demonstrated that the naturally occurring anion nitrite (NO(2)(-)) is a bioactive storage reservoir for NO, and is reduced to NO under conditions of hypoxia and acidosis. We hypothesized that nitrite infused intravenously could attenuate the hemodynamic changes associated with APT. APT was induced with autologous blood clots injected into the right atrium in mongrel dogs. After APT (or saline), the dogs received an intravenous nitrite (or saline) infusion (6.75 micromol/kg over 15 min and then 0.28 micromol/kg/min) and hemodynamic evaluations were carried out for 2 h. Plasma nitrite concentrations were measured using ozone-based reductive chemiluminescence methodologies. APT decreased cardiac index (CI) and increased pulmonary vascular resistance index (PVRI); these effects were improved during infusions of sodium nitrite. Accordingly, nitrite infusion increased cardiac index by 28%, reduced the PVRI by 48%, and the systemic vascular resistance index (SVRI) by 21% in embolized dogs, suggesting a greater effect on the ischemic embolized vascular system than the systemic circulation following embolization. Interestingly, in nonembolized control dogs the same nitrite infusion decreased MAP and CI (all P<0.05). The nitrite infusion increased plasma nitrite concentrations by approximately 2 microM, and produced dose-dependent effects on PVRI, MAP, and SVRI. Remarkably, blood levels of nitrite as low as 500 nM decreased PVRI and SVRI in this model, suggesting a potential role of nitrite in physiological blood flow regulation. These results suggest that a low-dose nitrite infusion produces beneficial hemodynamic effects in a dog model of APT. These findings suggest a new therapeutic application for nitrite and support emerging evidence for a surprisingly potent and potentially physiological vasoactivity of nitrite.

  15. Spectrophotometric determination of nitrite and nitrate using phosphomolybdenum blue complex.

    PubMed

    Zatar, N A; Abu-Eid, M A; Eid, A F

    1999-11-15

    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 color or the rate of its decrease is found to be directly proportional to the amount of nitrite added. The absorbance of the phosphomolybdenum blue complex is monitored spectrophotometrically at 814 nm and related to the concentration of nitrite present. The effect of different factors such as acidity, stability of the complex, time, temperature, phosphate concentration, molybdenum concentration, sodium sulfide concentration and the tolerance amount of other ions have been reported. Maximum absorbance is at 814 nm. The range of linearity using the conventional method is 0.5-2.0 ppm with molar absorptivity of 1.1 x 10(4) l mol(-1) cm(-1). and a relative standard deviation of 2.6% for five measurements. The range of linearity using the reaction rate method is 0.2-3.6 ppm with a relative standard deviation of 2.4% for five measurements. The method is applied for determination of nitrite and nitrate in water, meat products and vegetables.

  16. Nitrate Reduction to Nitrite, a Possible Source of Nitrite for Growth of Nitrite-Oxidizing Bacteria

    PubMed Central

    Belser, L. W.

    1977-01-01

    Growth yields and other parameters characterizing the kinetics of growth of nitrite-oxidizing bacteria are presented. These parameters were measured during laboratory enrichments of soil samples with added nitrite. They were then used to reanalyze data for nitrite oxidizer growth in a previously reported field study (M. G. Volz, L. W. Belser, M. S. Ardakani, and A. D. McLaren, J. Environ. Qual. 4:179-182, 1975), where nitrate, but not nitrite or ammonium, was added. In that report, analysis of the field data indicated that in unsaturated soils, the reduction of nitrate to nitrite may be a significant source of nitrite for the growth of nitrite oxidizers. A yield of 1.23 × 104 cells per μg of N was determined to be most appropriate for application to the field. It was determined that if nitrite came only from mineralized organic nitrogen via ammonium oxidation, 35 to 90% of the organic nitrogen would have had to have been mineralized to produce the growth observed. However, it is estimated that only about 2% of the organic nitrogen could have been mineralized during the growth period. Thus, it appears that another source of nitrite is required, the most likely being the reduction of nitrate to nitrite coupled to the oxidation of organic matter. PMID:921264

  17. The use of atmospheric pressure plasma-treated water as a source of nitrite for emulsion-type sausage.

    PubMed

    Jung, Samooel; Kim, Hyun Joo; Park, Sanghoo; In Yong, Hae; Choe, Jun Ho; Jeon, Hee-Joon; Choe, Wonho; Jo, Cheorun

    2015-10-01

    We investigated the possible use of atmospheric pressure plasma-treated water (PTW) as a nitrite source in curing process. Emulsion-type sausages were manufactured with PTW, celery powder containing nitrite, and synthetic sodium nitrite at a concentration of nitrite ion 70mgkg(-1). In terms of sausage quality, there were no noticeable effects of PTW on the total aerobic bacterial counts, color, and peroxide values of sausages compared with those of celery powder and sodium nitrite throughout 28days of storage at 4°C. Sausage with added PTW had lower concentrations of residual nitrite compared to those of added celery powder and sodium nitrite during the storage period (P<0.05). The sensory properties of PTW-treated and sodium nitrite-treated sausages were not different, whereas the sausage with added celery powder received the lowest scores in taste and acceptability. From the results, it is concluded that PTW can be used as a nitrite source equivalent to a natural curing agent.

  18. Schwertmannite stability in acidified coastal environments

    NASA Astrophysics Data System (ADS)

    Collins, Richard N.; Jones, Adele M.; Waite, T. David

    2010-01-01

    A combination of analytical and field measurements has been used to probe the speciation and cycling of iron in coastal lowland acid sulfate soils. Iron K-edge EXAFS spectroscopy demonstrated that schwertmannite dominated (43-77%) secondary iron mineralization throughout the oxidized and acidified soil profile, while pyrite and illite were the major iron-bearing minerals in the reduced potential acid sulfate soil layers. Analyses of contemporary precipitates from shallow acid sulfate soil groundwaters indicated that 2-line ferrihydrite, in addition to schwertmannite, is presently controlling secondary Fe(III) mineralization. Although aqueous pH values and concentrations of Fe(II) were seasonally high, no evidence was obtained for the Fe(II)-catalyzed crystallization of either mineral to goethite. The results of this study indicate that: (a) schwertmannite is likely to persist in coastal lowland acid sulfate soils on a much longer time-scale than predicted by laboratory experiments; (b) this mineral is less reactive in these types of soils due to surface-site coverage by components such as silicate and possibly, to a lesser extent, natural organic matter and phosphate and; (c) active water table management to promote oxic/anoxic cycles around the Fe(II)-Fe(III) redox couple, or reflooding of these soils, will be ineffective in promoting the Fe(II)-catalyzed transformation of either schwertmannite or 2-line ferrihydrite to crystalline iron oxyhydroxides.

  19. 75 FR 59268 - Draft Guidance for Industry: Acidified Foods; Availability

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-27

    ... and in employing appropriate quality control procedures. Under the draft guidance, processors of non... safe manufacturing, processing, and packing processes and in employing appropriate quality control... Establishment-Specific Written Quality Control Plans and Recordkeeping for Acidified Foods, and...

  20. LOW DOSE NITRITE ENHANCES PERFUSION AFTER FLUID RESUSCITATION FROM HEMORRHAGIC SHOCK

    PubMed Central

    Cabrales, Pedro

    2010-01-01

    This study determines the systemic and microvascular hemodynamic consequences of administering a low dose sodium nitrite after fluid resuscitation from hemorrhagic shock. Hemodynamic responses to hemorrhagic shock and resuscitation were studied in the hamster window chamber model. Moderated hemorrhage was induced by arterial controlled bleeding of 50% of the blood volume (BV) and the hypovolemic state was maintained for one hour. Volume restitution was performed by infusion of 25% of BV using Hextend® (6% Hetastarch 670 kDa in lactated electrolyte solution) 10 min after fluid resuscitation 100μl of specific concentrations of sodium nitrite were infused. The experimental groups were named based on the nitrite concentration used, namely: 0 μM, 10 μM and 50 μM. Systemic parameters, microvascular hemodynamics and capillary perfusion (functional capillary density, FCD) were followed during entire protocol. Exogenous 10 μM nitrite maintained systemic and microhemodynamic conditions post fluid resuscitation from hemorrhagic shock, compared to 50 μM or no nitrite. A moderated increase in plasma nitrite during the early phase of resuscitation reversed arteriolar vasoconstriction and increased capillary perfusion and venous return, improving central cardiac function. Nitrite effects on resistance vessels, directly influenced intravascular pressure redistribution, sustained blood flow, and prevented tissue ischemia. In conclusion, increasing nitrite plasma bioavailability after fluid resuscitation from hemorrhagic shock can be a potential therapy to enhance microvascular perfusion and to improve overall outcome. PMID:19804938

  1. Nitrite toxicity of Litopenaeus vannamei in water containing low concentrations of sea salt or mixed salts

    USGS Publications Warehouse

    Sowers, A.; Young, S.P.; Isely, J.J.; Browdy, C.L.; Tomasso, J.R.

    2004-01-01

    The uptake, depuration and toxicity of environmental nitrite was characterized in Litopenaeus vannamei exposed in water containing low concentrations of artificial sea salt or mixed salts. In 2 g/L artificial sea salts, nitrite was concentrated in the hemolymph in a dose-dependent and rapid manner (steady-state in about 2 d). When exposed to nitrite in 2 g/L artificial sea salts for 4 d and then moved to a similar environment without added nitrite, complete depuration occurred within a day. Increasing salinity up to 10 g/L decreased uptake of environmental nitrite. Nitrite uptake in environments containing 2 g/L mixed salts (combination of sodium, potassium, calcium and magnesium chlorides) was similar to or lower than rates in 2 g/L artificial sea salt. Toxicity was inversely related to total dissolved salt and chloride concentrations and was highest in 2 g/L artificial sea salt (96-h medial lethal concentration = 8.4 mg/L nitrite-N). Animals that molted during the experiments did not appear to be more susceptible to nitrite than animals that did not molt. The shallow slope of the curve describing the relationship between toxicity and salinity suggests that management of nitrite toxicity in low-salinity shrimp ponds by addition of more salts may not be practical. ?? Copyright by the World Aquaculture Society 2004.

  2. Dietary nitrite induces occludin nitration in the stomach.

    PubMed

    Rocha, Bárbara S; Correia, Mariana G; Fernandes, Rita C; Gonçalves, João S; Laranjinha, João

    2016-01-01

    The clinical implications of the nitrate-nitrite-nitric oxide pathway have been extensively studied in recent years. However, the physiological impact of bioactive nitrogen oxides produced from dietary nitrate has remained largely elusive. Here, we report a hitherto unrecognized nitrite-dependent nitrating pathway that targets tight junction proteins in the stomach. Inorganic nitrate, nitrite or saliva obtained after the consumption of lettuce were administered by oral gavage to Wistar rats. The enterosalivary circulation of nitrate was allowed to occur for 4 h after which the animals were euthanized and the stomach collected. Nitrated occludin was detected by immunoprecipitation in the gastric epithelium upon inorganic nitrite administration (p < .05) but was not observed in the case of inorganic nitrate or human saliva administration. This observation, along with differences in (•)NO production rates from inorganic and salivary nitrite under simulated gastric conditions, suggests that competing reactions at acidic pH determine the production of nitrating agents ((•)NO2) or other, more stable, oxides. Accordingly, it is shown in vitro that salivary nitrite yields higher steady state concentrations of (•)NO (0.37 ± 0.01 μM) than sodium nitrite (0.12 ± 0.03 μM). Dietary-dependent reactions involving the production of nitrogen oxides should be further investigated as, in the context of occludin nitration, the consumption of green leafy vegetables (with high nitrate content), if able to modulate gut barrier function, may have important implications in the context of leaky gut disorders.

  3. Nitrate reduction to nitrite, nitric oxide and ammonia by gut bacteria under physiological conditions.

    PubMed

    Tiso, Mauro; Schechter, Alan N

    2015-01-01

    The biological nitrogen cycle involves step-wise reduction of nitrogen oxides to ammonium salts and oxidation of ammonia back to nitrites and nitrates by plants and bacteria. Neither process has been thought to have relevance to mammalian physiology; however in recent years the salivary bacterial reduction of nitrate to nitrite has been recognized as an important metabolic conversion in humans. Several enteric bacteria have also shown the ability of catalytic reduction of nitrate to ammonia via nitrite during dissimilatory respiration; however, the importance of this pathway in bacterial species colonizing the human intestine has been little studied. We measured nitrite, nitric oxide (NO) and ammonia formation in cultures of Escherichia coli, Lactobacillus and Bifidobacterium species grown at different sodium nitrate concentrations and oxygen levels. We found that the presence of 5 mM nitrate provided a growth benefit and induced both nitrite and ammonia generation in E.coli and L.plantarum bacteria grown at oxygen concentrations compatible with the content in the gastrointestinal tract. Nitrite and ammonia accumulated in the growth medium when at least 2.5 mM nitrate was present. Time-course curves suggest that nitrate is first converted to nitrite and subsequently to ammonia. Strains of L.rhamnosus, L.acidophilus and B.longum infantis grown with nitrate produced minor changes in nitrite or ammonia levels in the cultures. However, when supplied with exogenous nitrite, NO gas was readily produced independently of added nitrate. Bacterial production of lactic acid causes medium acidification that in turn generates NO by non-enzymatic nitrite reduction. In contrast, nitrite was converted to NO by E.coli cultures even at neutral pH. We suggest that the bacterial nitrate reduction to ammonia, as well as the related NO formation in the gut, could be an important aspect of the overall mammalian nitrate/nitrite/NO metabolism and is yet another way in which the microbiome

  4. Growth and blood chemistry of ducklings reared on acidified wetlands

    USGS Publications Warehouse

    Rattner, B.A.; Haramis, G.; Linder, G.; Chu, D.

    1985-01-01

    Acid deposition is one factor that may be responsible for the decline of some waterfowl populations. Growth and physiological condition were monitored in captive-reared black ducks (Anas rubripes) exposed for 10-day trials (day 11-20 of life) on control (pH 6.8) and acidified (pH 5.0) man-made emergent wetlands. Impaired growth (body weight, culmen and tarsus length) and increased mortality (50%) were apparent in broods (hen + 4 ducklings) reared on acidified wetIands. Ducklings exbibiting poor growth had reduced hematocrit, plasma protein and cholesterol levels. This subset of birds had elevated plasma uric acid concentration and creatine kinase activity (perhaps due to enhanced protein and nucleotide catabolism). and elevated pIasma K+ levels. Based upon overt appearance, growth and blood chemistry, ducklings exposed to acidified wetlands were concluded to be in poorer condittion than those exposed on circumneutral pH wetlands.

  5. The protective potential of Yucca schidigera (Sarsaponin 30) against nitrite-induced oxidative stress in rats.

    PubMed

    Cigerci, I Hakki; Fidan, A Fatih; Konuk, Muhsin; Yuksel, Hayati; Kucukkurt, Ismail; Eryavuz, Abdullah; Sozbilir, Nalan Baysu

    2009-07-01

    The present study was designed to determine the protective effects of Yucca schidigera (Ys) against oxidative damage induced by acute nitrite intoxication as well as the histopathological evaluation of Ys in rats. The rats were divided into three groups each containing 12 rats: control (C); nitrite intoxication (N); Ys + nitrite intoxication (NY). C and N groups were fed standard rat feed (SRF). The NY group was fed SRF + 100 ppm Ys powder for 4 weeks. Acute nitrite intoxication was induced by subcutaneous (s.c.) administration of sodium nitrite (60 mg/kg) 1 day after the feeding period. Fifty minutes after sodium nitrite administration, blood samples and tissues including lung, liver, and kidney were collected for clinical biochemistry and histopathological investigations. Ys treatment was found to decrease methemoglobin, blood and tissue malondialdehyde, and tissue nitric oxide concentrations, and to increase the glutathione in blood and various tissues. However, plasma nitric oxide, total antioxidant activity, beta-carotene, and vitamin A did not differ between N and NY groups. While the N group rats showed distinct pathology in various tissues (compared with controls), the NY group had similar lung and liver pathology to the control. Only moderate or mild hemorrhage and hyperemia were seen in kidneys of NY group rats. Consequently, the natural compounds found in Ys, such as polyphenols, steroidal saponins, and other phytonutrients, could be used to substantially protect the organism from nitrite-induced oxidative damage and its complications.

  6. [Protonation of nitrite is an obligatory stage in the generation of nitric oxide from nitrite in biological systems].

    PubMed

    Mikoian, V D; Kubrina, L N; Khachatrian, G N; Vanin, A F

    2006-01-01

    The yield of nitric oxide from 1 mM sodium nitrite differs 200 times when the process was initiated by 10 mM sodium dithionite in the solution of 5 or 150 mM HEPES-buffer (pH 7.4). Dithionite acted both as a strong reductant and an agent that induced a local acidification of solutions without notable change in pH value. The amount of nitric oxide was estimated by the EPR method by measuring the incorporation of nitric oxide to water-soluble complexes of Fe with N-methyl-D-glucamine dithiocarbamate (MGD), which led to the formation of EPR-detectable mononitrosyl iron complexes with MGD (MNIC-MGD). Ten seconds after dithionite addition, the concentration of MNIC - MGD complexes reached 2 microM in 5 mM HEPES-buffer in contrast to 0.01 microM in 150 mM HEPES-buffer. The difference was suggested to be due to a higher life-time of zones with decreased pH values in a weaker weak buffer solution. The life-time was high enough to ensure the protonation of a part of nitrite. The resulting nitrous acid was decomposed to form nitric oxide. The difference in the formation of nitric oxide from nitrite was also observed in weak and strong buffer solutions in the presence of hemoglobin (0.3 mM) or serum albumin (0.5 mM). However, the ratios of nitric oxide yields in weak and strong buffer did not exceed 3-4 times. The increase in the formation of nitric oxide from nitrite was characteristic for the solutions containing both proteins. Large amounts of nitric oxide formed from nitrite was observed in mouse liver preparation subjected to freezing-thawing procedure followed by incubation in 150 mM HEPES-buffer (pH 7.4) and addition of dithionite. The proposition was made that the presence of zones with low pH value in cells and tissues can ensure the predominant operation of the acid mechanism formation of nitric oxide from nitrite. The contribution of the formation of nitric oxide from nitrite catalyzing with heme-containing proteins nitrite reductases can be minor one under these

  7. An Evaluation of Alternatives to Nitrites and Sulfites to Inhibit the Growth of Salmonella enterica and Listeria monocytogenes in Meat Products

    PubMed Central

    Lamas, Alexandre; Miranda, José Manuel; Vázquez, Beatriz; Cepeda, Alberto; Franco, Carlos Manuel

    2016-01-01

    In recent years, the use of nitrites and sulfites as food preservatives has been a cause for concern due to the health problems that these additives can cause in humans. Natural products have been studied as an alternative, but most of them have hardly been applied in the food industry for technological and economic reasons. In this sense, organic salts such as sodium acetate are a good alternative due to their affordability. Thus, this study evaluated the capacity of sodium nitrite, sodium sulfite, a sodium acetate product (TQI C-6000), and chitosan to inhibit two important foodborne pathogens, Salmonella enterica and Listeria monocytogenes. The MIC of each chemical was in vitro evaluated and their antibacterial action was subsequently checked in situ using minced meat as a food model. MIC values of sodium nitrite (10,000 mg/L) and sodium sulfite (50,000 mg/L) for Salmonella enterica were higher than the values allowed by legislation (450 mg/L for sulfites and 150 mg/L for nitrites). Additionally, the sodium acetate product caused the inhibition of Salmonella enterica and Listeria at a relative low quantity. The two foodborne pathogens were inhibited in the food model with 1% of the sodium acetate product. Additionally, there were no significant differences between sodium nitrite, sodium sulfite, and sodium acetate products in the inhibition of Salmonella enterica and Listeria monocytogenes in the food model. Thus, products based on sodium acetate can be an alternative to traditional preservatives in food products. PMID:28231169

  8. An Evaluation of Alternatives to Nitrites and Sulfites to Inhibit the Growth of Salmonella enterica and Listeria monocytogenes in Meat Products.

    PubMed

    Lamas, Alexandre; Miranda, José Manuel; Vázquez, Beatriz; Cepeda, Alberto; Franco, Carlos Manuel

    2016-10-31

    In recent years, the use of nitrites and sulfites as food preservatives has been a cause for concern due to the health problems that these additives can cause in humans. Natural products have been studied as an alternative, but most of them have hardly been applied in the food industry for technological and economic reasons. In this sense, organic salts such as sodium acetate are a good alternative due to their affordability. Thus, this study evaluated the capacity of sodium nitrite, sodium sulfite, a sodium acetate product (TQI C-6000), and chitosan to inhibit two important foodborne pathogens, Salmonella enterica and Listeria monocytogenes. The MIC of each chemical was in vitro evaluated and their antibacterial action was subsequently checked in situ using minced meat as a food model. MIC values of sodium nitrite (10,000 mg/L) and sodium sulfite (50,000 mg/L) for Salmonella enterica were higher than the values allowed by legislation (450 mg/L for sulfites and 150 mg/L for nitrites). Additionally, the sodium acetate product caused the inhibition of Salmonella enterica and Listeria at a relative low quantity. The two foodborne pathogens were inhibited in the food model with 1% of the sodium acetate product. Additionally, there were no significant differences between sodium nitrite, sodium sulfite, and sodium acetate products in the inhibition of Salmonella enterica and Listeria monocytogenes in the food model. Thus, products based on sodium acetate can be an alternative to traditional preservatives in food products.

  9. Nitrite spray treatment to promote red color stability of vacuum packaged beef.

    PubMed

    Song, Xiao; Cornforth, Daren; Whittier, Dick; Luo, Xin

    2015-01-01

    Sodium nitrite solutions were sprayed on select grade boneless rib (M. longissimus thoracis) and bottom round (mainly M. biceps femoris) steaks individually, to form bright red nitric oxide myoglobin (NO-Mb) in vacuum packages. Our objective was to determine the optimum level of nitrite in spray for stable raw steak redness, low or no residual nitrite, and low surface pinking (ham-like cured color) after cooking. Results showed that steaks sprayed with 100-350 ppm nitrite solutions had 3.0-3.6g weight gain and a calculated level of 1.3-5.3mg nitrite added/kg steak, but very low (<1 ppm) residual nitrite. Nitrite sprays of 250-350 ppm were optimum for raw steak color during 21 days of storage at 1°C (a*>10; chroma C*>16). Raw steak redness was less stable in round than rib. Visual scores for pinkness after cooking were low, indicating that cooked color at even the highest nitrite treatment (350 ppm) was acceptable.

  10. Properties of reformulated hot dog sausage without added nitrites during chilled storage.

    PubMed

    Ruiz-Capillas, C; Herrero, A M; Tahmouzi, S; Razavi, S H; Triki, M; Rodríguez-Salas, L; Samcová, K; Jiménez-Colmenero, F

    2016-01-01

    The aim of this study was to assess the effect of a complete nitrite replacement strategy using celery, carmine, sodium lactate and orange dietary fibre combined with vitamins C and E, on the quality characteristics (technological, sensorial and safety properties) of hot dog sausages (five samples) during chilled storage (2 ± 1℃ 60 days). Nitrite replacers (combined with vitamins C and E) presented antioxidant activity, reducing lipid oxidation in reformulated samples. At the end of storage redness (a*) was similar in the control sample (with added nitrite) and in the sample without added nitrite. Sensory evaluation detected no significant difference between samples with and without added nitrite. All the reformulated samples were judged acceptable by the panellists. At the end of storage, the control sample contained more than four times as much residual nitrite as the reformulated samples. Growth of presumptive Clostridium perfringens was not observed in any of the samples. Samples without added nitrite had longer shelf-lives than control sausage. Samples containing 0.1% vitamin C registered the lowest microbiological levels. This strategy could be a good alternative to reduce and/or eliminate added nitrite in hot dog sausages.

  11. Determination of Nitrite in Whole Blood by High-Performance Liquid Chromatography with Electrochemical Detection and a Case of Nitrite Poisoning.

    PubMed

    Yan, Hui; Zhuo, Xiangyi; Shen, Baohua; Xiang, Ping; Shen, Min

    2016-01-01

    Although nitrite is widely used in meat processing, it is a major toxicity hazard to children and is responsible for the blue-baby syndrome. A simple and effective method to determine nitrite in whole blood has been devised using ion chromatography with suppressed conductivity detection. The blood sample was deproteinized by adding acetonitrile and purified with mini-cartridges to remove hydrophobic compounds, chloride ions, and metal ions. An aliquot of the filtrate was injected onto the ion chromatography. The retention time for nitrite was 13.8 min and the detection limit of nitrite in whole blood was 0.4 μmol/L. The calibration curve was linear (r(2) = 0.9999) over the concentration working range. The blood nitrite concentration of a victim who attempted suicide by ingesting sodium nitrite powder was determined using the present method. The basal levels for nitrite in human blood was determined with 7.1 ± 0.9 μmol/L (n = 12).

  12. Formation of sodium chlorate in diaphragmed chlorine electrolyzers

    SciTech Connect

    Gorbachev, A.K.; Andryushchenko, F.K.; Maksimchuk, E.F.; Potapov, V.N.

    1985-11-01

    This paper examines the formation of sodium chlorate under conditions of diaphragmed electrolysis with ruthenium-titanium oxide anodes. The authors establish that the sodium chlorate is formed chemically in such an electrolyzer. The data indicate that effective methods of reducing the amounts of sodium chlorate in diaphragm chlorine electrolyzers are to supply an acidified brine and to ensure catalytic decomposition of hypochlorous acid and sodium chlorate directly in the electrolyzer.

  13. Dietary nitrite improves insulin signaling through GLUT4 translocation.

    PubMed

    Jiang, Hong; Torregrossa, Ashley C; Potts, Amy; Pierini, Dan; Aranke, Mayank; Garg, Harsha K; Bryan, Nathan S

    2014-02-01

    Diabetes mellitus type 2 is a syndrome of disordered metabolism with inappropriate hyperglycemia owing to a reduction in the biological effectiveness of insulin. Type 2 diabetes is associated with an impaired nitric oxide (NO) pathway that probably serves as the key link between metabolic disorders and cardiovascular disease. Insulin-mediated translocation of GLUT4 involves the PI3K/Akt kinase signal cascade that results in activation of endothelial NO synthase (eNOS). eNOS is dysfunctional during diabetes. We hypothesize that loss of eNOS-derived NO terminates the signaling cascade and therefore cannot activate GLUT4 translocation and that dietary nitrite may repair this pathway. In this study, we administered 50mg/L sodium nitrite to db/db diabetic mice for 4 weeks. After 4 weeks treatment, the db/db mice experienced less weight gain, improved fasting glucose levels, and reduced insulin levels. Cell culture experiments using CHO-HIRc-myc-GLUT4eGFP cell lines stably expressing insulin receptor and myc-GLUT4eGFP protein, as well as L6 skeletal muscle cells stably expressing rat GLUT4 with a Myc epitope (L6-GLUT4myc), showed that NO, nitrite, and GSNO stimulate GLUT4 translocation independent of insulin, which is inhibited by NEM. Collectively our data suggest that nitrite improves insulin signaling through restoration of NO-dependent nitrosation of GLUT4 signaling translocation. These data suggest that NO-mediated nitrosation of GLUT4 by nitrite or other nitrosating agents is necessary and sufficient for GLUT4 translocation in target tissue. Description of this pathway may justify a high-nitrate/nitrite diet along with the glycemic index to provide a safe and nutritional regimen for the management and treatment of diabetes.

  14. Antagonism of Acute Sulfide Poisoning in Mice by Nitrite Anion without Methemoglobinemia.

    PubMed

    Cronican, Andrea A; Frawley, Kristin L; Ahmed, Humza; Pearce, Linda L; Peterson, Jim

    2015-07-20

    There are currently no FDA-approved antidotes for H2S/sulfide intoxication. Sodium nitrite, if given prophylactically to Swiss Webster mice, was shown to be highly protective against the acute toxic effects of sodium hydrosulfide (∼LD40 dose) with both agents administered by intraperitoneal injections. However, sodium nitrite administered after the toxicant dose did not detectably ameliorate sulfide toxicity in this fast-delivery, single-shot experimental paradigm. Nitrite anion was shown to rapidly produce NO in the bloodstream, as judged by the appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin, together amounting to less than 5% of the total hemoglobin present. Sulfide-intoxicated mice were neither helped by the supplemental administration of 100% oxygen nor were there any detrimental effects. Compared to cyanide-intoxicated mice, animals surviving sulfide intoxication exhibited very short knockdown times (if any) and full recovery was extremely fast (∼15 min) irrespective of whether sodium nitrite was administered. Behavioral experiments testing the ability of mice to maintain balance on a rotating cylinder showed no motor impairment up to 24 h post sulfide exposure. It is argued that antagonism of sulfide inhibition of cytochrome c oxidase by NO is the crucial antidotal activity of nitrite rather than formation of methemoglobin.

  15. Nitrite toxicity to the crayfish Procambarus clarkii

    SciTech Connect

    Gutzmer, M.P.; Tomasso, J.R.

    1985-03-01

    The purpose of this study was to determine the effects of acute nitrite exposure to the crayfish Procambarus clarkii (Decapoda). Specific objectives of this study included (1) determining the 24-, 48-, 72- and 96-h LC-50's of nitrite to crayfish of different weights and genders in freshwater, (2) determining the LC-50's of nitrite to crayfish in water with elevated chloride concentrations, and (3), in order to gain insight into the mechanisms of nitrite toxicity in crayfish, determining hemolymph nitrite concentrations in crayfish exposed to nitrite in freshwater and water with elevated chloride concentrations.

  16. Comparative Behaviour of Nitrite and Nitrate for the Protection of Rebar Corrosion

    NASA Astrophysics Data System (ADS)

    Ahmad, Altaf; Kumar, Anil

    2016-10-01

    Corrosion of rebar steel due to environmental causes has been studied through various approaches, and among the protection techniques use of inhibitors has gained encouragement. Nitrites and nitrates of sodium have gained sufficient scientific coverage. Recently, nitrites and nitrates of calcium have been verified in some studies, which, however, needs further experimentation through different angles. Simple polarization technique has been utilized in the present study to compare inhibitive efficiency of these salts of sodium and calcium, which indicate that calcium salts are more efficient.

  17. The Effects of Physicochemical Factors and Cell Density on Nitrite Transformation in a Lipid-Rich Chlorella.

    PubMed

    Liang, Fang; Du, Kui; Wen, Xiaobin; Luo, Liming; Geng, Yahong; Li, Yeguang

    2015-12-28

    To understand the effects of physicochemical factors on nitrite transformation by microalgae, a lipid-rich Chlorella with high nitrite tolerance was cultured with 8 mmol/l sodium nitrite as sole nitrogen source under different conditions. The results showed that nitrite transformation was mainly dependent on the metabolic activities of algal cells rather than oxidation of nitrite by dissolved oxygen. Light intensity, temperature, pH, NaHCO3 concentrations, and initial cell densities had significant effects on the rate of nitrite transformation. Single-factor experiments revealed that the optimum conditions for nitrite transformation were light intensity: 300 μmol/m(2); temperature: 30°C; pH: 7-8; NaHCO3 concentration: 2.0 g/l; and initial cell density: 0.15 g/l; and the highest nitrite transformation rate of 1.36 mmol/l/d was achieved. There was a positive correlation between nitrite transformation rate and the growth of Chlorella. The relationship between nitrite transformation rate (mg/l/d) and biomass productivity (g/l/d) could be described by the regression equation y = 61.3x (R(2) = 0.9665), meaning that 61.3 mg N element was assimilated by 1.0 g dry biomass on average, which indicated that the nitrite transformation is a process of consuming nitrite as nitrogen source by Chlorella. The results demonstrated that the Chlorella suspension was able to assimilate nitrite efficiently, which implied the feasibility of using flue gas for mass production of Chlorella without preliminary removal of NOX.

  18. Thermophilic treatment of acidified and partially acidified wastewater using an anaerobic submerged MBR: Factors affecting long-term operational flux.

    PubMed

    Jeison, D; van Lier, J B

    2007-09-01

    The long-term operation of two thermophilic anaerobic submerged membrane bioreactors (AnSMBRs) was studied using acidified and partially acidified synthetic wastewaters. In both reactors, cake formation was identified as the key factor governing critical flux. Even though cake formation was observed to be mostly reversible, particle deposition proceeds fast once the critical flux is exceeded. Very little irreversible fouling was observed during long-term operation, irrespective of the substrate. Critical flux values at the end of the reactors operation were 7 and 3L/m(2)h for the AnSMBRs fed with acidified and partially acidified wastewaters, respectively, at a gas superficial velocity of 70m/h. Small particle size was identified as the responsible parameter for the low observed critical flux values. The degree of wastewater acidification significantly affected the physical properties of the sludge, determining the attainable flux. Based on the fluxes observed in this research, the membrane costs would be in the range of 0.5euro/m(3) of treated wastewater. Gas sparging was ineffective in increasing the critical flux values. However, preliminary tests showed that cross-flow operation may be a feasible alternative to reduce particle deposition.

  19. Treatment of Acidified Blood Using Reduced Osmolarity Mixed-Base Solutions

    PubMed Central

    Mason, Thomas G.; Kraut, Jeffrey A.

    2016-01-01

    We hypothesize that reduced osmolarity mixed-base (ROMB) solutions can potentially serve as customizable treatments for acidoses, going beyond standard solutions in clinical use, such as 1.0 M sodium bicarbonate. Through in silico quantitative modeling, by treating acidified canine blood using ROMB solutions, and by performing blood-gas and optical microscopy measurements in vitro, we demonstrate that ROMB solutions having a high proportion of a strong base, such as disodium carbonate or sodium hydroxide, can be effective in reducing carbon dioxide pressure PCO2 while raising pH and bicarbonate ion concentration without causing significant osmotic damage to red blood cells, which can occur during rapid administration of hypertonic solutions of weak bases. These results suggest that a ROMB solution, which is composed mostly of a strong base, could be administered in a safe and effective manner, when compared to a hypertonic solution of sodium bicarbonate. Because of the reduced osmolarity and the customizable content of strong base in ROMB solutions, this approach differs from prior approaches involving hypertonic solutions that only considered a single molar ratio of strong to weak base. Our calculations and measurements suggest that custom-tailored ROMB solutions merit consideration as potentially efficacious treatments for specific types of acidosis, particularly acute metabolic acidosis and acute respiratory acidosis. PMID:28082905

  20. Effect of inhaled nitric oxide on cerebrospinal fluid and blood nitrite concentrations in newborn lambs

    PubMed Central

    Conahey, George R.; Power, Gordon G.; Hopper, Andrew O.; Terry, Michael H.; Kirby, Laura S.; Blood, Arlin B.

    2009-01-01

    Inhaled nitric oxide (iNO) has many extrapulmonary effects. As the half-life of NO in blood is orders of magnitude less than the circulation time from lungs to the brain, the mediator of systemic effects of iNO is unknown. We hypothesized that concentrations of nitrite, a circulating byproduct of NO with demonstrated NO bioactivity, would increase in blood and cerebrospinal fluid (CSF) during iNO therapy. iNO (80ppm) was given to six newborn lambs and results compared to six control lambs. Blood and CSF nitrite concentrations increased two-fold in response to iNO. cGMP increased in blood but not CSF suggesting brain guanylate cyclase activity was not increased. When sodium nitrite was infused intravenously blood and CSF nitrite levels increased within 10 min and reached similar levels of 14.6±1.5 µM after 40 min. The reactivity of nitrite in hemoglobin-free brain homogenates was investigated, with the findings that nitrite did not disappear nor did measurable amounts of s-nitroso, n-nitroso, or iron-nitrosyl-species appear. We conclude that although nitrite diffuses freely between blood and CSF, due to its lack of reactivity in the brain, nitrite’s putative role as the mediator of the systemic effects of iNO is limited to intravascular reactions. PMID:18535482

  1. Prevalence of nitrite and nitrate contents and its effect on edible bird nest's color.

    PubMed

    Paydar, Mohammadjavad; Wong, Yi Li; Wong, Won Fen; Hamdi, Omer Abdalla Ahmed; Kadir, Noraniza Abd; Looi, Chung Yeng

    2013-12-01

    Edible bird nests (EBNs) are important ethnomedicinal commodity in the Chinese community. Recently, But and others showed that the white EBNs could turn red by vapors from sodium nitrite (NaNO2) in acidic condition or from bird soil, but this color-changing agent remained elusive. The aim of this study was to determine the prevalence of nitrite and nitrate contents and its affects on EBN's color. EBNs were collected from swiftlet houses or caves in Southeast Asia. White EBNs were exposed to vapor from NaNO2 in 2% HCl, or bird soil. The levels of nitrite (NO2-) and nitrate (NO3-) in EBNs were determined through ion chromatography analysis. Vapors from NaNO2 in 2% HCl or bird soil stained white bird nests to brown/red colors, which correlated with increase nitrite and nitrate levels. Moreover, naturally formed cave-EBNs (darker in color) also contained higher nitrite and nitrate levels compared to white house-EBNs, suggesting a relationship between nitrite and nitrate with EBN's color. Of note, we detected no presence of hemoglobin in red "blood" nest. Using infrared spectra analysis, we demonstrated that red/brown cave-EBNs contained higher intensities of C-N and N-O bonds compared to white house-EBNs. Together, our study suggested that the color of EBNs was associated with the prevalence of the nitrite and nitrate contents.

  2. Immediate Reduction of Salmonella enterica Serotype Typhimurium Viability via Membrane Destabilization following Exposure to Multiple-Hurdle Treatments with Heated, Acidified Organic Acid Salt Solutions▿†

    PubMed Central

    Milillo, S. R.; Martin, E.; Muthaiyan, A.; Ricke, S. C.

    2011-01-01

    The antimicrobial activity of organic acids in combination with nonchemical treatments was evaluated for inactivation of Salmonella enterica serotype Typhimurium within 1 min. It was observed that the effectiveness of the multiple-hurdle treatments was temperature (P ≤ 0.05) and pH (P ≤ 0.05) dependent and corresponded to the degree of organic acid lipophilicity (sodium acetate being least effective and sodium propionate being the most effective). This led to the hypothesis that the loss in viability was due at least in part to cell membrane disruption. Evaluation of osmotic response, potassium ion leakage, and transmission electron micrographs confirmed treatment effects on the cell membrane. Interestingly, all treatments, even those with no effect on viability, such as with sodium acetate, resulted in measurable cellular stress. Microarray experiments explored the specific response of S. Typhimurium to sodium acetate and sodium propionate, the most similar of the tested treatments in terms of pKa and ionic strength, and found little difference in the changes in gene expression following exposure to either, despite their very different effects on viability. Taken together, the results reported support our hypothesis that treatment with heated, acidified, organic acid salt solutions for 1 min causes loss of S. Typhimurium viability at least in part by membrane damage and that the degree of effectiveness can be correlated with lipophilicity of the organic acid. Overall, the data presented here indicate that a combined thermal, acidified sodium propionate treatment can provide an effective antimicrobial treatment against Salmonella. PMID:21478311

  3. Acute, sublethal cyanide poisoning in mice is ameliorated by nitrite alone: complications arising from concomitant administration of nitrite and thiosulfate as an antidotal combination.

    PubMed

    Cambal, Leah K; Swanson, Megan R; Yuan, Quan; Weitz, Andrew C; Li, Hui-Hua; Pitt, Bruce R; Pearce, Linda L; Peterson, Jim

    2011-07-18

    Sodium nitrite alone is shown to ameliorate sublethal cyanide toxicity in mice when given from ∼1 h before until 20 min after the toxic dose as demonstrated by the recovery of righting ability. An optimum dose (12 mg/kg) was determined to significantly relieve cyanide toxicity (5.0 mg/kg) when administered to mice intraperitoneally. Nitrite so administered was shown to rapidly produce NO in the bloodsteam as judged by the dose-dependent appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin. It is argued that antagonism of cyanide inhibition of cytochrome c oxidase by NO is the crucial antidotal activity rather than the methemoglobin-forming action of nitrite. Concomitant addition of sodium thiosulfate to nitrite-treated blood resulted in the detection of sulfidomethemoblobin by EPR spectroscopy. Sulfide is a product of thiosulfate hydrolysis and, like cyanide, is known to be a potent inhibitor of cytochrome c oxidase, the effects of the two inhibitors being essentially additive under standard assay conditions rather than dominated by either one. The findings afford a plausible explanation for an observed detrimental effect in mice associated with the use of the standard nitrite-thiosulfate combination therapy at sublethal levels of cyanide intoxication.

  4. [Electrical activity and circulatory effects of nitrite in the rat cerebrum].

    PubMed

    Shumilova, T E; Smirnov, A G; Shereshkov, V I; Fedorova, M A; Nozdrachev, A D

    2015-01-01

    An association between the cerebrum electrical activity (CEA) in rats, blood supply of its cortex microregions (linear blood flow), and general cerebrum blood flow under acute nitrite hypoxia was studied. The phase character of the change in hemodynamic indices and the total capacity of electroencephalography (EEG) spectrum for 75 min after sodium nitrite introduction (30 mg/kg of body weight) was detected. The first phase (30 min) was associated with cerebrum adaptation to hypotension caused by nitrite and was completed by EEG normalization. The second phase was characterized by pathological EEG changes (in spite of restoration of hemodynamics in the cerebrum) caused by the growth of oxygen debt in the nervous tissue as a result of a decrease in the blood oxygen capacity by 60-75 min of the effect of nitrite.

  5. Role of xanthine oxidoreductase in the anti-thrombotic effects of nitrite in rats in vivo.

    PubMed

    Kramkowski, K; Leszczynska, A; Przyborowski, K; Kaminski, T; Rykaczewska, U; Sitek, B; Zakrzewska, A; Proniewski, B; Smolenski, R T; Chabielska, E; Buczko, W; Chlopicki, S

    2016-01-01

    The mechanisms underlying nitrite-induced effects on thrombosis and hemostasis in vivo are not clear. The goal of the work described here was to investigate the role of xanthine oxidoreductase (XOR) in the anti-platelet and anti-thrombotic activities of nitrite in rats in vivo. Arterial thrombosis was induced electrically in rats with renovascular hypertension by partial ligation of the left renal artery. Sodium nitrite (NaNO2, 0.17 mmol/kg twice daily for 3 days, p.o) was administered with or without one of the XOR-inhibitors: allopurinol (ALLO) and febuxostat (FEB) (100 and 5 mg/kg, p.o., for 3 days). Nitrite treatment (0.17 mmol/kg), which was associated with a significant increase in NOHb, nitrite/nitrate plasma concentration, resulted in a substantial decrease in thrombus weight (TW) (0.48 ± 0.03 mg vs. vehicle [VEH] 0.88 ± 0.08 mg, p < 0.001) without a significant hypotensive effect. The anti-thrombotic effect of nitrite was partially reversed by FEB (TW = 0.63 ± 0.06 mg, p < 0.05 vs. nitrites), but not by ALLO (TW = 0.43 ± 0.02 mg). In turn, profound anti-platelet effect of nitrite measured ex vivo using collagen-induced whole-blood platelet aggregation (70.5 ± 7.1% vs. VEH 100 ± 4.5%, p < 0.05) and dynamic thromboxaneB2 generation was fully reversed by both XOR-inhibitors. In addition, nitrite decreased plasminogen activator inhibitor-1 concentration (0.47 ± 0.13 ng/ml vs. VEH 0.62 ± 0.04 ng/ml, p < 0.05) and FEB/ALLO reversed this effect. In vitro the anti-platelet effect of nitrite (1 mM) was reversed by FEB (0.1 mM) under hypoxia (0.5%O2) and normoxia (20%O2). Nitrite treatment had no effect on coagulation parameters. In conclusion, the nitrite-induced anti-platelet effect in rats in vivo is mediated by XOR, but XOR does not fully account for the anti-thrombotic effects of nitrite.

  6. Toxicity of nitrite to fish: a review

    SciTech Connect

    Lewis, W.M. Jr.; Morris, D.P.

    1986-03-01

    Nitrite, an intermediate in the oxidation of ammonium to nitrate, changes hemoglobin to methemoglobin, which does not carry oxygen; nitrite may thus cause anoxia in fish and other aquatic organisms. The published literature on nitrite toxicity to fish, which consists of about 40 papers, shows that the ratio of the 24-h LC50 (concentration lethal to half of the test organisms in 24 h) to the 96-h LC50 has a median value of 2.0 and is fairly uniform across species; toxicity tests of differing duration can therefore be standardized to a common duration. In general, chronic effects are difficult to detect at concentrations below one-fifth of the 96-h LC50. Most fish concentrate nitrite in fresh water; chloride in the external environment offsets the toxicity of nitrite by competing with nitrite for uptake through the chloride cells of the gills. Bicarbonate also reduces the toxicity of nitrite, but it is less than 1% as effective as chloride. Calcium reduces the toxicity of nitrite, but much less than chloride; the effects of other metal cations have not been studied. Hydrogen ion concentration of the medium has not been shown to have a discrete effect on the toxicity of nitrite except at extreme concentrations uncharacteristic of the environments in which fish ordinarily live. Nitrite toxicity is exacerbated by low oxygen concentrations because nitrite reduces the oxygen-carrying capacity of the blood. Very small fish seem less sensitive to nitrite than fish of intermediate or large size. Present evidence suggests that salmonids are among the fishes most sensitive to nitrite. The least-sensitive species tested thus far are the largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus; the largemouth bass does not concentrate nitrite.

  7. Randomised phase 2 trial of intra-coronary nitrite during acute myocardial infarction

    PubMed Central

    Jones, Daniel A; Pellaton, Cyril; Velmurugan, Shanti; Rathod, Krishnaraj Sinha; Andiapen, Mervyn; Antoniou, Sotiris; van Eijl, Sven; Webb, Andrew J; Westwood, Mark A; Parmar, Mahesh K; Mathur, Anthony; Ahluwalia, Amrita

    2015-01-01

    Rationale Pre-clinical evidence demonstrates that inorganic nitrite, following its in situ conversion to nitric oxide, attenuates consequent myocardial reperfusion injury. Objective We investigated whether intra-coronary injection of nitrite during primary percutaneous coronary intervention (PCI) might improve infarct size in ST-elevated myocardial infarction (STEMI). Methods and Results Patients undergoing primary PCI (n=80) were randomised to receive intracoronary (10mL) sodium nitrite (1.8μmol) or NaCl (placebo) before balloon inflation. The primary endpoint was infarct size assessed by measuring creatine kinase (CK) release. Secondary outcomes included infarct size assessed by troponin T release and by cardiac magnetic resonance imaging (CMR) on day 2. Baseline characteristics were similar between the groups. No evidence of differences in CK release (p=0.92), troponin T (p=0.85) or CMR-assessed infarct size (p=0.254) were evident. In contrast there was an improvement in myocardial salvage index (p=0.05) and reduction in MACE at 1 year (2.6% vs 15.8%, p=0.04) in the nitrite group. In a 66-patient sub-group with TIMI≤1 flow there was reduced serum CK (p=0.030) and a 19% reduction in CMR-determined infarct size (p=0.034) with nitrite. No adverse effects of nitrite were detected. Conclusions In this phase II study intra-coronary nitrite infusion did not alter infarct size although a trend to improved myocardial salvage index and a significant reduction in MACE was evident. In a sub-group of patients with TIMI flow≤1 nitrite reduced infarct size and MACE and improved myocardial salvage index indicating that a phase III clinical trial assessing intra-coronary nitrite administration as an adjunct to PCI in STEMI patients is warranted. Clinical Trial Registration URL: http://clinicaltrials.gov NCT01584453. PMID:25512434

  8. Acidifier application rate impacts on ammonia emissions from US roaster chicken houses

    NASA Astrophysics Data System (ADS)

    Shah, Sanjay B.; Grimes, Jesse L.; Oviedo-Rondón, Edgar O.; Westerman, Philip W.

    2014-08-01

    Due to its potential environmental and public health impacts, emissions of ammonia (NH3) as well as several other gases from US livestock farms may be regulated. Broiler houses are important sources of NH3 emissions. However, there are no emissions data from roaster (8-12 wk old broilers, ˜4 kg ea.) houses. Producers treat the litter in broiler houses with acidifiers, such as sodium bisulfate (SBS, NaHSO4) to reduce ammonia production and protect bird health. However, there is very little data on the effect of acidifiers, particularly at high application rates on ammonia emissions. The impact of different SBS application rates [High (0.95-1.46 kg m-2, whole house), Medium (0.73 kg m-2, whole house), Low (0.37-0.49 kg m-2, whole house), and Control (0.37-0.49 kg m-2, brood chamber)] on ammonia emissions was evaluated in commercial roaster houses over 22 months spanning eight flocks. Ammonia emission from each fan was measured with an acid scrubber that operated only when the fan operated. Emissions were calculated using >95% measured data with the rest being estimated using robust methods. Exhaust ammonia-N concentrations were inversely correlated with the SBS application rates. Emission rates on animal unit (AU, where 1 AU = 500 kg live-mass) basis (ER, g d-1 AU-1) were reduced by 27, 13, and 5%, respectively, in the High, Medium, and Low treatments vs. the Control treatment (mean: 100 g d-1 AU-1, range: 86-114 g d-1 AU-1). Emission rates for the Control treatment measured in this study on roasters were mostly higher than ERs in the literature. Differences in ERs are not only due to diet, environmental and management conditions, but also due to measurement methods.

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

    PubMed

    Sungur, Şana; Atan, Muhammet Meriç

    2013-01-01

    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 perchlorate analysed via ion chromatography. The detected sodium nitrate and nitrite amounts in meat consumed in the Hatay region are less than the maximum levels as declared in the Turkish Food Codex. The amount of perchlorate was considered not to pose a threat as well. However, in 50% of the cheese samples, sodium nitrate amounts were found to be more than the maximum acceptable level in the Turkish Food Codex.

  10. The effect of nitrite and starter culture on microbiological quality of "chorizo"-a Spanish dry cured sausage.

    PubMed

    González, B; Díez, V

    2002-03-01

    The effect of nitrite and starter culture on the survival of Enterobacteriaceae, Micrococcaceae, Lactic acid bacteria and other microorganisms was evaluated during ripening of "chorizo", a Spanish dry sausage. Sodium nitrite 50 and 150 ppm and Lactobacillus sake CL35 added to the "chorizo" have a significant inhibitory effect on Enterobacteriaceae counts but did not on Micrococcaceae. The use of Lact. sake could be an adequate safety factor in this product.

  11. Reactions of (+)-catechin with salivary nitrite and thiocyanate under conditions simulating the gastric lumen: production of dinitrosocatechin and its thiocyanate conjugate.

    PubMed

    Takahama, U; Yamauchi, R; Hirota, S

    2014-08-01

    Catechins are ingested as food components and supplements. It is known that catechins are transformed to dinitrosocatechins by nitrite under acidic conditions, suggesting the possibility of their formation in the stomach because saliva contains nitrite. This paper deals with nitrite-induced transformation of (+)-catechin in methanol extracts of adzuki bean into 6,8-dinitrosocatechin in acidified saliva (pH ≈ 1.9). As the mechanism of its formation, addition of nitric oxide (NO) to (+)-catechin semiquinone radical, both of which were produced in nitrous acid/(+)-catechin systems, was proposed. The dinitrosocatechin was oxidized to the quinone by nitrous acid, and the quinone reacted with a salivary component thiocyanate producing 6'-thiocyanato-6,8-dinitrosocatechin. Since quinones are toxic, we propose a function of thiocyanate as a scavenger of the o-quinone formed from dinitrosocatechins in the stomach.

  12. Nitrate Reductase Regulates Expression of Nitrite Uptake and Nitrite Reductase Activities in Chlamydomonas reinhardtii 1

    PubMed Central

    Galván, Aurora; Cárdenas, Jacobo; Fernández, Emilio

    1992-01-01

    In Chlamydomonas reinhardtii mutants defective at the structural locus for nitrate reductase (nit-1) or at loci for biosynthesis of the molybdopterin cofactor (nit-3, nit-4, or nit-5 and nit-6), both nitrite uptake and nitrite reductase activities were repressed in ammonium-grown cells and expressed at high amounts in nitrogen-free media or in media containing nitrate or nitrite. In contrast, wild-type cells required nitrate induction for expression of high levels of both activities. In mutants defective at the regulatory locus for nitrate reductase (nit-2), very low levels of nitrite uptake and nitrite reductase activities were expressed even in the presence of nitrate or nitrite. Both restoration of nitrate reductase activity in mutants defective at nit-1, nit-3, and nit-4 by isolating diploid strains among them and transformation of a structural mutant upon integration of the wild-type nit-1 gene gave rise to the wild-type expression pattern for nitrite uptake and nitrite reductase activities. Conversely, inactivation of nitrate reductase by tungstate treatment in nitrate, nitrite, or nitrogen-free media made wild-type cells respond like nitrate reductase-deficient mutants with respect to the expression of nitrite uptake and nitrite reductase activities. Our results indicate that nit-2 is a regulatory locus for both the nitrite uptake system and nitrite reductase, and that the nitrate reductase enzyme plays an important role in the regulation of the expression of both enzyme activities. PMID:16668656

  13. Determination of five abused drugs in nitrite-adulterated urine by immunoassays and gas chromatography-mass spectrometry.

    PubMed

    Tsai, S C; ElSohly, M A; Dubrovsky, T; Twarowska, B; Towt, J; Salamone, S J

    1998-10-01

    The adulteration of urine specimens with nitrite ion hasseen shown to mask the gas chromatography-mass spectrometry (GC-MS) confirmation testing of marijuana use. This study was designed to further investigate the effect of nitrite adulteration on the detection of five commonly abused drugs by immunoassay screening and GC-MS analysis. The drugs tested are cocaine metabolite (benzoylecgonine), morphine, 11-nor-delta-tetrahydrocannabinol-9-carboxylic acid (THCCOOH), amphetamine, and phencyclidine. The immunoassays evaluated included the instrument-based Abuscreen ONLINE assays, the on-site Abuscreen ONTRAK assays, and the one-step ONTRAK TESTCUP-5 assay. Multianalyte standards containing various levels of drugs were used to test the influence of both potassium and sodium nitrite. In the ONLINE immunoassays, the presence of up to 1.0M nitrite in the multianalyte standards had no significant effect for benzoylecgonine, morphine, and phencyclidine assays. With a high concentration of nitrite, ONLINE became more sensitive for amphetamine (detected more drug than what was expected) and less sensitive for THCCOOH (detected less drug than what was expected). No effects of nitrite were observed on the results of the Abuscreen ONTRAK assays. Similarly, no effects were observed on the absolute qualitative results of the TESTCUP-5 when testing the nitrite-adulterated standards. However, the produced intensities of the signals that indicate the negative test results were slightly lowered in the THC and phencyclidine assays. The presence of 1.0M of nitrite did not show dramatic interference with the GC-MS analysis of benzoylecgonine, morphine, amphetamine, and phencyclidine. In contrast, nitrite ion significantly interfered with the detection of THCCOOH by GC-MS. The presence of 0.03M of nitrite ion resulted in significant loss in the recovery of THCCOOH and its internal standard by GC-MS. The problem of nitrite adulteration could be alleviated by sodium bisulfite treatment even

  14. Use of gamma radiation on control of Clostridium botulinum in mortadella formulated with different nitrite levels

    NASA Astrophysics Data System (ADS)

    Dutra, Monalisa Pereira; Aleixo, Glécia de Cássia; Ramos, Alcinéia de Lemos Souza; Silva, Maurício Henriques Louzada; Pereira, Marcio Tadeu; Piccoli, Roberta Hilsdorf; Ramos, Eduardo Mendes

    2016-02-01

    This study investigated the effects of applying different doses of gamma radiation (0, 10 and 20 kGy) on Clostridium botulinum spores (107 spores/g) inoculated into mortadellas with different nitrite contents (0, 150 and 300 ppm). We also evaluated the order of application of heat (cooking) and irradiation processing. The products were evaluated for survival of C. botulinum, pH, water activity (Aw), redox potential (Eh) and residual nitrite content. In the non-irradiated raw batters, almost all spores could be recovered when no nitrite was added and only half was recovered with the addition of 150 ppm of nitrite. The use of 150 ppm of nitrite was able to inhibit the germination or growth of C. botulinum in non-irradiated cooked mortadellas after 48 h of processing. However, after 30 days of chilling storage (4 °C), it was possible to recover 105 UFC/g of this microorganism. The gamma irradiation (>10 kGy) had a positive effect on the inactivation of C. botulinum in mortadellas, independent of the sodium nitrite level used and the cooking/irradiation processing order.

  15. 21 CFR 862.1510 - Nitrite (nonquantitative) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nitrite (nonquantitative) test system. 862.1510... Systems § 862.1510 Nitrite (nonquantitative) test system. (a) Identification. A nitrite (nonquantitative) test system is a device intended to identify nitrite in urine. Nitrite identification is used in...

  16. 21 CFR 862.1510 - Nitrite (nonquantitative) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nitrite (nonquantitative) test system. 862.1510... Systems § 862.1510 Nitrite (nonquantitative) test system. (a) Identification. A nitrite (nonquantitative) test system is a device intended to identify nitrite in urine. Nitrite identification is used in...

  17. 21 CFR 862.1510 - Nitrite (nonquantitative) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nitrite (nonquantitative) test system. 862.1510... Systems § 862.1510 Nitrite (nonquantitative) test system. (a) Identification. A nitrite (nonquantitative) test system is a device intended to identify nitrite in urine. Nitrite identification is used in...

  18. 21 CFR 862.1510 - Nitrite (nonquantitative) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nitrite (nonquantitative) test system. 862.1510... Systems § 862.1510 Nitrite (nonquantitative) test system. (a) Identification. A nitrite (nonquantitative) test system is a device intended to identify nitrite in urine. Nitrite identification is used in...

  19. Influence of acid tolerance responses on survival, growth, and thermal cross-protection of Escherichia coli O157:H7 in acidified media and fruit juices.

    PubMed

    Ryu, J H; Beuchat, L R

    1998-12-22

    A study was done to determine survival and growth characteristics of acid-adapted, acid-shocked, and control cells of Escherichia coli O157:H7 inoculated into tryptic soy broth (TSB) acidified with organic acids and three commercial brands of apple cider and orange juice. The three types of cells behaved similarly in TSB acidified with acetic acid; however, in TSB (pH 3.9) acidified with lactic acid, acid-adapted cells were more tolerant than acid-shocked cells which, in turn, were more tolerant than control cells. The ability of the three types of cells to grow after inoculation into acidified TSB, then plated on tryptic soy agar containing sodium chloride was determined. Tolerance of acid-adapted cells and, less markedly, acid-shocked cells to sodium chloride was diminished, compared to control cells. The pathogen showed extraordinary tolerance to the low pH of apple cider and orange juice held at 5 or 25 degrees C for up to 42 days. Growth occurred in one brand of apple cider (pH 3.98) incubated at 25 degrees C. Regardless of test parameters, there was no indication that cell types differed in tolerance to the acidic environment in apple cider or orange juice. Survival of control, acid-adapted, and acid-shocked cells heated in apple cider and orange juice was studied. Within each apple cider or orange juice, D(52 degrees C)-values of acid-adapted cells were considerably higher than those of acid-shocked or control cells, which indicates that heat tolerance can be substantially enhanced by acid adaptation compared to acid shock.

  20. Spectrophotometric determination of nitrogen dioxide in air and nitrite in water and soil samples

    SciTech Connect

    Pandurangappa, M.; Balasubramanian, N.

    1995-02-01

    A sensitive spectrophotometric method for the determination of nitrogen dioxide in air and nitrite in water and soil samples is described. Nitrogen dioxide in air is fixed as nitrite ion in alkaline sodium arsenite or in triethanolamine absorber solutions. The method is based on the diazo coupling reaction between p-nitro aniline and 1-hydroxy-2-naphthoic acid. The azo dye formed under aqueous condition has an absorption maximum at 585nm and obeys Beer`s law over the range 0-25{mu}g of nitrite. The colour system is stable for 72h. The relative standard deviation is 2.7% for ten determinations at 15{mu}g of nitrite. The dye is extracted with 1:1 isoamyl alcohol-IBMK mixture and stabilisation with methanolic potassium hydroxide showed {lambda}{sub max} at 610nm. It obeys Beer`s law over the range 0-4{mu}g of nitrite. The colour system is stable for 40h in organic phase and the relative standard deviation is 2.5% for ten determinations at 3{mu}g of nitrite. The molar absorptivity of the colour system is 3.68 x 10{sup 4} Lmol{sup {minus}1} cm{sup {minus}1}. The effect of interfering gases and other ions on the determination of nitrite is described. The developed method has been applied for the determination of residual nitrogen dioxide gas present in the laboratory fume cupboard and automobile exhaust gases. In addition, the method has been applied for the determination of nitrite and nitrate in samples like water, soil and radiator coolants.

  1. Effects of acidifying reagents on microwave treatment of dairy manure.

    PubMed

    Srinivasan, Asha; Nkansah-Boadu, Frank; Liao, Ping H; Lo, Kwang V

    2014-01-01

    Dairy manure, acidified using organic acids (acetic, oxalic, and citric acid) were treated with microwave enhanced advanced oxidation process (MW/H2O2-AOP). The effect of a mixture of oxalic acid and commonly used mineral acids (sulfuric and hydrochloric acid) on MW/H2O2-AOP was also examined. Substantial amounts of phosphorus were released under MW/H2O2-AOP, regardless of organic acid or mineral acid used. All three organic acids were good acidifying reagents; however, only oxalic acid could remove free calcium ion in the solution, and improve settleability of dairy manure. The MW/H2O2-AOP and calcium removal process could be combined into a single-stage process, which could release phosphate, solubilize solids and remove calcium from dairy manure at the same time. A mixture of oxalic acid and mineral acid produced the maximum volume of clear supernatant and had an ideal molar ratio of calcium to magnesium for effective struvite (magnesium ammonium phosphate) crystallization process. A single-stage MW/H2O2-AOP would simplify the process and reduce mineral acid consumption compared to a two-stage operation. The results of a pilot scale study demonstrate that MW/H2O2-AOP is effective in treating manure and recovering resource from dairy farms.

  2. Effects of nitrite exposure on functional haemoglobin levels, bimodal respiration, and swimming performance in the facultative air-breathing fish Pangasianodon hypophthalmus.

    PubMed

    Lefevre, Sjannie; Jensen, Frank B; Huong, Do T T; Wang, Tobias; Phuong, Nguyen T; Bayley, Mark

    2011-07-01

    In this study we investigated nitrite (NO₂⁻) effects in striped catfish, a facultative air-breather. Fish were exposed to 0, 0.4, and 0.9 mM nitrite for 0, 1, 2, 4, and 7 days, and levels of functional haemoglobin, methaemoglobin (metHb) and nitrosyl haemoglobin (HbNO) were assessed using spectral deconvolution. Plasma concentrations of nitrite, nitrate, chloride, potassium, and sodium were also measured. Partitioning of oxygen consumption was determined to reveal whether elevated metHb (causing functional hypoxia) induced air-breathing. The effects of nitrite on maximum oxygen uptake (MO(2max)) and critical swimming speed (U(crit)) were also assessed. Striped catfish was highly tolerant to nitrite exposure, as reflected by a 96 h LC₅₀ of 1.65 mM and a moderate nitrite uptake into the blood. Plasma levels of nitrite reached a maximum after 1 day of exposure, and then decreased, never exceeding ambient levels. MetHb, HbNO and nitrate (a nitrite detoxification product) also peaked after 1 day and then decreased. Only high levels of nitrite and metHb caused reductions in MO(2max) and U(crit). The response of striped catfish contrasts with that seen in most other fish species and discloses efficient mechanisms of combating nitrite threats. Furthermore, even though striped catfish is an efficient air-breather, this species has the ability to sustain aerobic scope and swimming performance without air-breathing, even when faced with nitrite-induced reductions in blood oxygen carrying capacity. Our study is the first to confirm that high levels of nitrite and metHb reduce MO(2max) and thereby aerobic scope, while more moderate elevations fail to do so. Further studies are needed to elucidate the mechanisms underlying the low nitrite accumulation in striped catfish.

  3. Nitrates, Nitrites, and Health. Bulletin 750.

    ERIC Educational Resources Information Center

    Deeb, Barbara S.; Sloan, Kenneth W.

    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…

  4. Implications of Decreased Nitrite Concentrations on Clostridium perfringens Outgrowth during Cooling of Ready-to-Eat Meats.

    PubMed

    Myers, Megan I; Sebranek, Joseph G; Dickson, James S; Shaw, Angela M; Tarté, Rodrigo; Adams, Kristin R; Neibuhr, Steve

    2016-01-01

    Increased popularity of natural and organic processed meats can be attributed to the growing consumer demand for preservative-free foods, including processed meats. To meet this consumer demand, meat processors have begun using celery juice concentrate in place of sodium nitrite to create products labeled as no-nitrate or no-nitrite-added meat products while maintaining the characteristics unique to conventionally cured processed meats. Because of flavor limitations, natural cures with celery concentrate typically provide lower ingoing nitrite concentrations for ready-to-eat processed meats than do conventional cures, which could allow for increased growth of pathogens, such as Clostridium perfringens, during cooked product cooling such as that required by the U.S. Department of Agriculture. The objective of this study was to investigate the implications associated with reduced nitrite concentrations for preventing C. perfringens outgrowth during a typical cooling cycle used for cooked products. Nitrite treatments of 0, 50, and 100 ppm were tested in a broth system inoculated with a three-strain C. perfringens cocktail and heated with a simulated product thermal process followed by a typical cooling-stabilization process. The nitrite concentration of 50 ppm was more effective for preventing C. perfringens outgrowth than was 0 ppm but was not as effective as 100 ppm. The interaction between nitrite and temperature significantly affected (P < 0.05) C. perfringens outgrowth in both total population and number of vegetative cells. Both temperature and nitrite concentration significantly affected (P < 0.05) C. perfringens spore survival, but the interaction between nitrite and temperature did not have a significant effect (P > 0.05) on spore outgrowth. Results indicate that decreased nitrite concentrations (50 ppm) have increased potential for total C. perfringens population outgrowth during cooling and may require additional protective measures, such as faster chilling

  5. Nitrite, nitrite alternatives, and the control of Clostridium botulinum in cured meats.

    PubMed

    Pierson, M D; Smoot, L A

    1982-01-01

    Historically, nitrite has been a component of meat-curing additives for several centuries. In recent years the safety of nitrite as an additive in cured meats has been questioned mainly because of the possible formation of carcinogenic nitrosamines. Nitrite has many important functions in meat curing including its role in color development, flavor, antioxidant properties, and antimicrobial activity. The inhibition of Clostridium botulinum growth and toxin production is an especially important antimicrobial property of nitrite. This review discusses the effects of processing, curing ingredients (especially nitrite), and storage of cured meats in relation to the control of C. botulinum. If nitrite is eliminated from cured meats or the level of usage decreased, then alternatives for the antibotulinal function of nitrite need to be considered. Several potential alternatives including sorbates, parabens, and biological acidulants are discussed.

  6. DFT Study on Nitrite Reduction Mechanism in Copper-Containing Nitrite Reductase.

    PubMed

    Lintuluoto, Masami; Lintuluoto, Juha M

    2016-01-12

    Dissimilatory reduction of nitrite by copper-containing nitrite reductase (CuNiR) is an important step in the geobiochemical nitrogen cycle. The proposed mechanisms for the reduction of nitrite by CuNiRs include intramolecular electron and proton transfers, and these two events are understood to couple. Proton-coupled electron transfer is one of the key processes in enzyme reactions. We investigated the geometric structure of bound nitrite and the mechanism of nitrite reduction on CuNiR using density functional theory calculations. Also, the proton transfer pathway, the key residues, and their roles in the reaction mechanism were clarified in this study. In our results, the reduction of T2 Cu site promotes the proton transfer, and the hydrogen bond network around the binding site has an important role not only to stabilize the nitrite binding but also to promote the proton transfer to nitrite.

  7. Physiological ecology of Mougeotia (Zygnemataceae) from an experimentally acidified lake

    SciTech Connect

    Arancibia-Avila, P.E.

    1994-01-01

    Filamentous green algae were collected in July, 1989, from metaphytic blooms that occurred in the acidified (pH 5.2) basin, but not an unacidified reference basin (pH 6.1) of Little Rock Lake, Vilas Co., WI. Isolates of a Mougeotia species and Spirogyra reflexa were cultured at pH 5.5, with aeration. Measurements Of O[sub 2] production in a factorial experiment revealed optimal irradiance and temperature for photosynthesis in Mougeotia were 2500 [mu]E[center dot]m[sup [minus]2][center dot]s[sup [minus]l] and 25[degrees]C. Additional O[sub 2] evolution measurements showed that the optimal pH for Mougeotia photosynthesis was 8, but that net photosynthesis was positive from pH 8 to 3. Further studies indicated that Mougeotia was tolerant to concentrations of zinc and aluminum that were greater than levels observed in the acidified basin of the lake. Since inorganic carbon (C[sub i]) is known to limit Mougeotia photosynthesis and growth in acidified lakes, the occurrence of carbonic anhydrase (CA) as a mechanism for uptake and concentration of C[sub i] was investigated. No CA activity was detected in S. reflexa. In contrast, both external and internal CA were measured in Mougeotia at pH 3.7 and at pH 8. By comparison to pH 8, at pH 3.7 external CA activity increased by a factor of about 2. An antibody to Chlamydomonas external CA was used to localize CA in the plasma membrane and cell wall of both Chlamydomonas and Mougeotia. When unaerated (DIC-limited) Mougeotia was grown in SD11 medium supplemented with 1% glucose, chlorophyll a levels were significantly higher than for cultures grown without sugar. Chloroplast morphology was also judged superior for sugar-supplemented cultures. The data suggest that Mougeotia possesses a DIC-concentrating system, and may also be able to import DOC (glucose).

  8. Extracellular DNA Acidifies Biofilms and Induces Aminoglycoside Resistance in Pseudomonas aeruginosa.

    PubMed

    Wilton, Mike; Charron-Mazenod, Laetitia; Moore, Richard; Lewenza, Shawn

    2015-11-09

    Biofilms consist of surface-adhered bacterial communities encased in an extracellular matrix composed of DNA, exopolysaccharides, and proteins. Extracellular DNA (eDNA) has a structural role in the formation of biofilms, can bind and shield biofilms from aminoglycosides, and induces antimicrobial peptide resistance mechanisms. Here, we provide evidence that eDNA is responsible for the acidification of Pseudomonas aeruginosa planktonic cultures and biofilms. Further, we show that acidic pH and acidification via eDNA constitute a signal that is perceived by P. aeruginosa to induce the expression of genes regulated by the PhoPQ and PmrAB two-component regulatory systems. Planktonic P. aeruginosa cultured in exogenous 0.2% DNA or under acidic conditions demonstrates a 2- to 8-fold increase in aminoglycoside resistance. This resistance phenotype requires the aminoarabinose modification of lipid A and the production of spermidine on the bacterial outer membrane, which likely reduce the entry of aminoglycosides. Interestingly, the additions of the basic amino acid L-arginine and sodium bicarbonate neutralize the pH and restore P. aeruginosa susceptibility to aminoglycosides, even in the presence of eDNA. These data illustrate that the accumulation of eDNA in biofilms and infection sites can acidify the local environment and that acidic pH promotes the P. aeruginosa antibiotic resistance phenotype.

  9. Improvement of heating uniformity in packaged acidified vegetables pasteurized with a 915 MHz continuous microwave system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continuous microwave processing to produce shelf-stable acidified vegetables with moderate to high salt contents poses challenges in pasteurization due to reduced microwave penetration depths and non-uniform heating. Cups of sweetpotato, red bell pepper, and broccoli acidified to pH 3.8 with citric...

  10. Growth potential of Clostridium perfringens from spores in acidified beef, pork and poultry products during chilling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of C. perfringens to germinate and grow in acidified ground beef as well as in ten commercially prepared acidified beef, pork and poultry products was assessed. The pH of ground beef was adjusted using organic vinegar to achieve various pH values between 5.0 and 5.6; the pH of the commer...

  11. [Microchip capillary electrophoresis-electrochemical detection of nitrite using a modified carbon paste electrode].

    PubMed

    Wei, Peihai; Li, Guanbin; Chen, Liren

    2005-05-01

    Carbon paste electrode modified with 3-mercaptopropyltrimethoxysilane copper (MPTMS-Cu) encapsulated in molecular sieve MCM-41 was prepared. The electrocatalytic behavior of the modified electrode towards the reduction of nitrite was studied in detail, including pH-dependence and composition-dependence studies. A microchip capillary electrophoresis-electrochemical detection system with the modified carbon paste as electrode was fabricated. The application of the system for the detection of nitrite is discussed. The detection was finished within 40 s under the following conditions: 50 mmol/L sodium acetate buffer at pH 5.8, -1.6 kV running voltage. The peak current was linear with the concentration of nitrite over 10.0 micromol/L-5.0 mmol/L and the detection limit was 4.0 micromol/L in pure water.

  12. Coral host cells acidify symbiotic algal microenvironment to promote photosynthesis.

    PubMed

    Barott, Katie L; Venn, Alexander A; Perez, Sidney O; Tambutté, Sylvie; Tresguerres, Martin

    2015-01-13

    Symbiotic dinoflagellate algae residing inside coral tissues supply the host with the majority of their energy requirements through the translocation of photosynthetically fixed carbon. The algae, in turn, rely on the host for the supply of inorganic carbon. Carbon must be concentrated as CO2 in order for photosynthesis to proceed, and here we show that the coral host plays an active role in this process. The host-derived symbiosome membrane surrounding the algae abundantly expresses vacuolar H(+)-ATPase (VHA), which acidifies the symbiosome space down to pH ∼ 4. Inhibition of VHA results in a significant decrease in average H(+) activity in the symbiosome of up to 75% and a significant reduction in O2 production rate, a measure of photosynthetic activity. These results suggest that host VHA is part of a previously unidentified carbon concentrating mechanism for algal photosynthesis and provide mechanistic evidence that coral host cells can actively modulate the physiology of their symbionts.

  13. Coral host cells acidify symbiotic algal microenvironment to promote photosynthesis

    PubMed Central

    Barott, Katie L.; Venn, Alexander A.; Perez, Sidney O.; Tambutté, Sylvie; Tresguerres, Martin

    2015-01-01

    Symbiotic dinoflagellate algae residing inside coral tissues supply the host with the majority of their energy requirements through the translocation of photosynthetically fixed carbon. The algae, in turn, rely on the host for the supply of inorganic carbon. Carbon must be concentrated as CO2 in order for photosynthesis to proceed, and here we show that the coral host plays an active role in this process. The host-derived symbiosome membrane surrounding the algae abundantly expresses vacuolar H+-ATPase (VHA), which acidifies the symbiosome space down to pH ∼4. Inhibition of VHA results in a significant decrease in average H+ activity in the symbiosome of up to 75% and a significant reduction in O2 production rate, a measure of photosynthetic activity. These results suggest that host VHA is part of a previously unidentified carbon concentrating mechanism for algal photosynthesis and provide mechanistic evidence that coral host cells can actively modulate the physiology of their symbionts. PMID:25548188

  14. Disrupting Hypoxia-Induced Bicarbonate Transport Acidifies Tumor Cells and Suppresses Tumor Growth.

    PubMed

    McIntyre, Alan; Hulikova, Alzbeta; Ledaki, Ioanna; Snell, Cameron; Singleton, Dean; Steers, Graham; Seden, Peter; Jones, Dylan; Bridges, Esther; Wigfield, Simon; Li, Ji-Liang; Russell, Angela; Swietach, Pawel; Harris, Adrian L

    2016-07-01

    Tumor hypoxia is associated clinically with therapeutic resistance and poor patient outcomes. One feature of tumor hypoxia is activated expression of carbonic anhydrase IX (CA9), a regulator of pH and tumor growth. In this study, we investigated the hypothesis that impeding the reuptake of bicarbonate produced extracellularly by CA9 could exacerbate the intracellular acidity produced by hypoxic conditions, perhaps compromising cell growth and viability as a result. In 8 of 10 cancer cell lines, we found that hypoxia induced the expression of at least one bicarbonate transporter. The most robust and frequent inductions were of the sodium-driven bicarbonate transporters SLC4A4 and SLC4A9, which rely upon both HIF1α and HIF2α activity for their expression. In cancer cell spheroids, SLC4A4 or SLC4A9 disruption by either genetic or pharmaceutical approaches acidified intracellular pH and reduced cell growth. Furthermore, treatment of spheroids with S0859, a small-molecule inhibitor of sodium-driven bicarbonate transporters, increased apoptosis in the cell lines tested. Finally, RNAi-mediated attenuation of SLC4A9 increased apoptosis in MDA-MB-231 breast cancer spheroids and dramatically reduced growth of MDA-MB-231 breast tumors or U87 gliomas in murine xenografts. Our findings suggest that disrupting pH homeostasis by blocking bicarbonate import might broadly relieve the common resistance of hypoxic tumors to anticancer therapy. Cancer Res; 76(13); 3744-55. ©2016 AACR.

  15. Gas chromatography-mass spectrometry analysis of nitrite in biological fluids without derivatization.

    PubMed

    Tsikas, Dimitrios; Böhmer, Anke; Mitschke, Anja

    2010-06-15

    We report on a gas chromatography-mass spectrometry (GC-MS) method for the quantification of nitrite in biological fluids without preceding derivatization. This method is based on the solvent extraction with ethyl acetate of nitrous acid (HONO, pK(a) = 3.29), i.e., HO(14)NO and (15)N-labeled nitrous acid (HO(15)NO) which was supplied as the sodium salt of (15)N-labeled nitrite and served as the internal standard. HO(14)NO and HO(15)NO react within the injector (at 300 degrees C) of the gas chromatograph with the solvent ethyl acetate to form presumably unlabeled and (15)N-labeled acetyl nitrite, respectively. Under negative ion chemical ionization (NICI) conditions with methane as the reagent gas, these species ionize to form O(14)NO(-) (m/z 46) and O(15)NO(-) (m/z 47), respectively. Quantification is performed by selected ion monitoring of m/z 46 for nitrite and m/z 47 for the internal standard. Nitrate at concentrations up to 20 mM does not interfere with nitrite analysis in this method. The GC-MS method was validated for the quantification of nitrite in aqueous buffer, human urine (1 mL, acidification) and saliva (0.1-1 mL, acidification), and hemolysates. The method was applied in studying reactions of nitrite (0-10 mM) with oxyhemoglobin ( approximately 6 mM) in lysed human erythrocytes (100 microL aliquots, no acidification).

  16. Effects of nitrite exposure on haematological parameters, oxidative stress and apoptosis in juvenile turbot (Scophthalmus maximus).

    PubMed

    Jia, Rui; Han, Cen; Lei, Ji-Lin; Liu, Bao-Liang; Huang, Bin; Huo, Huan-Huan; Yin, Shu-Ting

    2015-12-01

    Nitrite (NO2(-)) is commonly present as contaminant in aquatic environment and toxic to aquatic organisms. In the present study, we investigated the effects of nitrite exposure on haematological parameters, oxidative stress and apoptosis in juvenile turbot (Scophthalmus maximus). Fish were exposed to various concentrations of nitrite (0, 0.02, 0.08, 0.4 and 0.8mM) for 96 h. Fish blood and gills were collected to assay haematological parameters, oxidative stress and expression of genes after 0, 24, 48 and 96 h of exposure. In blood, the data showed that the levels of methemoglobin (MetHb), triglyceride (TG), potassium (K(+)), cortisol, heat shock protein 70 (HSP70) and glucose significantly increased in treatments with higher concentrations of nitrite (0.4 and/or 0.8mM) after 48 and 96 h, while the levels of haemoglobin (Hb) and sodium (Na(+)) significantly decreased in these treatments. In gills, nitrite (0.4 and/or 0.8mM) apparently reduced the levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glutathione (GSH), increased the formation of malondialdehyde (MDA), up-regulated the mRNA levels of c-jun amino-terminal kinase (JUK1), p53, caspase-3, caspase-7 and caspase-9 after 48 and 96 h of exposure. The results suggested caspase-dependent and JUK signaling pathways played important roles in nitrite-induced apoptosis in fish. Further, this study provides new insights into how nitrite affects the physiological responses and apoptosis in a marine fish.

  17. Properties of aqueous nitrate and nitrite from x-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Smith, Jacob W.; Lam, Royce K.; Shih, Orion; Rizzuto, Anthony M.; Prendergast, David; Saykally, Richard J.

    2015-08-01

    Nitrate and nitrite ions are of considerable interest, both for their widespread use in commercial and research contexts and because of their central role in the global nitrogen cycle. The chemistry of atmospheric aerosols, wherein nitrate is abundant, has been found to depend on the interfacial behavior of ionic species. The interfacial behavior of ions is determined largely by their hydration properties; consequently, the study of the hydration and interfacial behavior of nitrate and nitrite comprises a significant field of study. In this work, we describe the study of aqueous solutions of sodium nitrate and nitrite via X-ray absorption spectroscopy (XAS), interpreted in light of first-principles density functional theory electronic structure calculations. Experimental and calculated spectra of the nitrogen K-edge XA spectra of bulk solutions exhibit a large 3.7 eV shift between the XA spectra of nitrate and nitrite resulting from greater stabilization of the nitrogen 1s energy level in nitrate. A similar shift is not observed in the oxygen K-edge XA spectra of NO3- and NO2-. The hydration properties of nitrate and nitrite are found to be similar, with both anions exhibiting a similar propensity towards ion pairing.

  18. Inorganic nitrite and chronic tissue ischaemia: a novel therapeutic modality for peripheral vascular diseases

    PubMed Central

    Pattillo, Christopher B.; Bir, Shyamal; Rajaram, Venkat; Kevil, Christopher G.

    2011-01-01

    Ischaemic tissue damage represents the ultimate form of tissue pathophysiology due to cardiovascular disease, which is the leading cause of morbidity and mortality across the globe. A significant amount of basic research and clinical investigation has been focused on identifying cellular and molecular pathways to alleviate tissue damage and dysfunction due to ischaemia and subsequent reperfusion. Over many years, the gaseous molecule nitric oxide (NO) has emerged as an important regulator of cardiovascular health as well as protector against tissue ischaemia and reperfusion injury. However, clinical translation of NO therapy for these pathophysiological conditions has not been realized for various reasons. Work from our laboratory and several others suggests that a new form of NO-associated therapy may be possible through the use of nitrite anion (sodium nitrite), a prodrug which can be reduced to NO in ischaemic tissues. In this manner, nitrite anion serves as a highly selective NO donor in ischaemic tissues without substantially altering otherwise normal tissue. This surprising and novel discovery has reinvigorated hopes for effectively restoring NO bioavailability in vulnerable tissues while continuing to reveal the complexity of NO biology and metabolism within the cardiovascular system. However, some concerns may exist regarding the effect of nitrite on carcinogenesis. This review highlights the emergence of nitrite anion as a selective NO prodrug for ischaemic tissue disorders and discusses the potential therapeutic utility of this agent for peripheral vascular disease. PMID:20851809

  19. Properties of aqueous nitrate and nitrite from x-ray absorption spectroscopy

    SciTech Connect

    Smith, Jacob W.; Lam, Royce K.; Saykally, Richard J.; Shih, Orion; Rizzuto, Anthony M.; Prendergast, David

    2015-08-28

    Nitrate and nitrite ions are of considerable interest, both for their widespread use in commercial and research contexts and because of their central role in the global nitrogen cycle. The chemistry of atmospheric aerosols, wherein nitrate is abundant, has been found to depend on the interfacial behavior of ionic species. The interfacial behavior of ions is determined largely by their hydration properties; consequently, the study of the hydration and interfacial behavior of nitrate and nitrite comprises a significant field of study. In this work, we describe the study of aqueous solutions of sodium nitrate and nitrite via X-ray absorption spectroscopy (XAS), interpreted in light of first-principles density functional theory electronic structure calculations. Experimental and calculated spectra of the nitrogen K-edge XA spectra of bulk solutions exhibit a large 3.7 eV shift between the XA spectra of nitrate and nitrite resulting from greater stabilization of the nitrogen 1s energy level in nitrate. A similar shift is not observed in the oxygen K-edge XA spectra of NO{sub 3}{sup −} and NO{sub 2}{sup −}. The hydration properties of nitrate and nitrite are found to be similar, with both anions exhibiting a similar propensity towards ion pairing.

  20. SLUDGE CHARACTERIZATION AND SRAT SIMULATIONS USING A NITRITE-FREE SLUDGE SIMULANT

    SciTech Connect

    Koopman, D.

    2009-12-17

    Understanding catalytic hydrogen generation is fundamental to the safe operation of the Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC). Two Sludge Receipt and Adjustment Tank (SRAT) simulations were completed at the Aiken County Technology Laboratory (ACTL) of the Savannah River National Laboratory (SRNL) using a nitrite-free starting simulant. One simulation was trimmed with Rh and Hg and the other with Ru and Hg. The two noble metals were trimmed at the upper end of the recent Rh-Ru-Hg study. Mercury was trimmed at 1.5 wt% in the total solids. Excess acid comparable in quantity to that in the recent Rh-Ru-Hg matrix study was used. In spite of the favorable conditions for hydrogen generation, virtually no hydrogen production was observed during either SRAT simulation. The Rh test result confirmed the postulated significance of nitrite ion to the catalytic reactions producing hydrogen in CPC testing with normal DWPF sludge simulants. As for Ru, however, previous testing has shown that Ru activated for hydrogen generation only after nitrite destruction. Therefore, Ru could have potentially been catalytically active from the start of the nitrite-free SRAT test, but no such activity was seen. The nitrite-free Ru test result suggests that the intermediate form detected in the bead-frit melter feed preparation Ru solubility profiles was some form of nitro-Ru complex. The nitro-Ru complex is apparently not catalytically active for hydrogen generation but is a precursor to the catalytically active form (presumably a different complex not involving nitrite ligands). Removing nitrite ion from the system prevented the Ru catalyst precursor from forming and consequently blocked formation of the catalytically active form. These results, along with the results of a simulation in which sodium nitrite was metered into the SRAT to prevent ligand substitution reactions that occur during nitrite destruction from occurring in order to reduce hydrogen generation

  1. Comparison of a Powdered, Acidified Liquid, and Non-Acidified Liquid Human Milk Fortifier on Clinical Outcomes in Premature Infants

    PubMed Central

    Thoene, Melissa; Lyden, Elizabeth; Weishaar, Kara; Elliott, Elizabeth; Wu, Ruomei; White, Katelyn; Timm, Hayley; Anderson-Berry, Ann

    2016-01-01

    We previously compared infant outcomes between a powdered human milk fortifier (P-HMF) vs. acidified liquid HMF (AL-HMF). A non-acidified liquid HMF (NAL-HMF) is now commercially available. The purpose of this study is to compare growth and outcomes of premature infants receiving P-HMF, AL-HMF or NAL-HMF. An Institutional Review Board (IRB) approved retrospective chart review compared infant outcomes (born < 2000 g) who received one of three HMF. Growth, enteral nutrition, laboratory and demographic data were compared. 120 infants were included (P-HMF = 46, AL-HMF = 23, NAL-HMF = 51). AL-HMF infants grew slower in g/day (median 23.66 vs. P-HMF 31.27, NAL-HMF 31.74 (p < 0.05)) and in g/kg/day, median 10.59 vs. 15.37, 14.03 (p < 0.0001). AL-HMF vs. NAL-HMF infants were smaller at 36 weeks gestational age (median 2046 vs. 2404 g, p < 0.05). However AL-HMF infants received more daily calories (p = 0.21) and protein (p < 0.0001), mean 129 cal/kg, 4.2 g protein/kg vs. P-HMF 117 cal/kg, 3.7 g protein/kg , NAL-HMF 120 cal/kg, 4.0 g protein/kg. AL-HMF infants exhibited lower carbon dioxide levels after day of life 14 and 30 (p < 0.0001, p = 0.0038). Three AL-HMF infants (13%) developed necrotizing enterocolitis (NEC) vs. no infants in the remaining groups (p = 0.0056). A NAL-HMF is the most optimal choice for premature human milk-fed infants in a high acuity neonatal intensive care unit (NICU). PMID:27472359

  2. Comparison of a Powdered, Acidified Liquid, and Non-Acidified Liquid Human Milk Fortifier on Clinical Outcomes in Premature Infants.

    PubMed

    Thoene, Melissa; Lyden, Elizabeth; Weishaar, Kara; Elliott, Elizabeth; Wu, Ruomei; White, Katelyn; Timm, Hayley; Anderson-Berry, Ann

    2016-07-26

    We previously compared infant outcomes between a powdered human milk fortifier (P-HMF) vs. acidified liquid HMF (AL-HMF). A non-acidified liquid HMF (NAL-HMF) is now commercially available. The purpose of this study is to compare growth and outcomes of premature infants receiving P-HMF, AL-HMF or NAL-HMF. An Institutional Review Board (IRB) approved retrospective chart review compared infant outcomes (born < 2000 g) who received one of three HMF. Growth, enteral nutrition, laboratory and demographic data were compared. 120 infants were included (P-HMF = 46, AL-HMF = 23, NAL-HMF = 51). AL-HMF infants grew slower in g/day (median 23.66 vs. P-HMF 31.27, NAL-HMF 31.74 (p < 0.05)) and in g/kg/day, median 10.59 vs. 15.37, 14.03 (p < 0.0001). AL-HMF vs. NAL-HMF infants were smaller at 36 weeks gestational age (median 2046 vs. 2404 g, p < 0.05). However AL-HMF infants received more daily calories (p = 0.21) and protein (p < 0.0001), mean 129 cal/kg, 4.2 g protein/kg vs. P-HMF 117 cal/kg, 3.7 g protein/kg , NAL-HMF 120 cal/kg, 4.0 g protein/kg. AL-HMF infants exhibited lower carbon dioxide levels after day of life 14 and 30 (p < 0.0001, p = 0.0038). Three AL-HMF infants (13%) developed necrotizing enterocolitis (NEC) vs. no infants in the remaining groups (p = 0.0056). A NAL-HMF is the most optimal choice for premature human milk-fed infants in a high acuity neonatal intensive care unit (NICU).

  3. Corrosion Behavior of Stainless Steels in Neutral and Acidified Sodium Chloride Solutions by Electrochemical Impedance Spectroscopy

    NASA Technical Reports Server (NTRS)

    Calle, L. M.; Kolady, M. R.; Vinje, R. D.

    2004-01-01

    The objective of this work was to evaluate the corrosion performance of three alloys by Electrochemical Impedance Spectroscopy (EIS) and to compare the results with those obtained during a two-year atmospheric exposure study.' Three alloys: AL6XN (UNS N08367), 254SM0 (UNS S32154), and 304L (UNS S30403) were included in the study. 304L was included as a control. The alloys were tested in three electrolyte solutions which consisted of neutral 3.55% NaC1, 3.55% NaC1 in 0.lN HC1, and 3.55% NaC1 in 1.ON HC1. These conditions were expected to be less severe, similar, and more severe respectively than the conditions at NASA's Kennedy Space Center launch pads.

  4. 21 CFR 862.1510 - Nitrite (nonquantitative) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Systems § 862.1510 Nitrite (nonquantitative) test system. (a) Identification. A nitrite (nonquantitative) test system is a device intended to identify nitrite in urine. Nitrite identification is used in the diagnosis and treatment of uninary tract infection of bacterial origin. (b) Classification. Class I...

  5. Oxygen isotopes in nitrite: Analysis, calibration, and equilibration

    USGS Publications Warehouse

    Casciotti, K.L.; Böhlke, J.K.; McIlvin, M.R.; Mroczkowski, S.J.; Hannon, J.E.

    2007-01-01

    Nitrite is a central intermediate in the nitrogen cycle and can persist in significant concentrations in ocean waters, sediment pore waters, and terrestrial groundwaters. To fully interpret the effect of microbial processes on nitrate (NO3-), nitrite (NO2-), and nitrous oxide (N2O) cycling in these systems, the nitrite pool must be accessible to isotopic analysis. Furthermore, because nitrite interferes with most methods of nitrate isotopic analysis, accurate isotopic analysis of nitrite is essential for correct measurement of nitrate isotopes in a sample that contains nitrite. In this study, nitrite salts with varying oxygen isotopic compositions were prepared and calibrated and then used to test the denitrifier method for nitrite oxygen isotopic analysis. The oxygen isotopic fractionation during nitrite reduction to N2O by Pseudomonas aureofaciens was lower than for nitrate conversion to N2O, while oxygen isotopic exchange between nitrite and water during the reaction was similar. These results enable the extension of the denitrifier method to oxygen isotopic analysis of nitrite (in the absence of nitrate) and correction of nitrate isotopes for the presence of nitrite in "mixed" samples. We tested storage conditions for seawater and freshwater samples that contain nitrite and provide recommendations for accurate oxygen isotopic analysis of nitrite by any method. Finally, we report preliminary results on the equilibrium isotope effect between nitrite and water, which can play an important role in determining the oxygen isotopic value of nitrite where equilibration with water is significant. ?? 2007 American Chemical Society.

  6. Prior exposure influences the behavioural avoidance by an intertidal gastropod, Bembicium auratum, of acidified waters

    NASA Astrophysics Data System (ADS)

    Amaral, Valter; Cabral, Henrique N.; Bishop, Melanie J.

    2014-01-01

    Phenotypic plasticity may be critical to the maintenance of viable populations under future environmental change. Here we examined the role of behavioural avoidance of sub-optimal conditions in enabling the intertidal gastropod, Bembicium auratum, to persist in mangrove forests affected by the low pH runoff from acid sulphate soils (ASS). Behaviourally, the gastropod may be able to avoid periods of particularly high acidity by using pneumatophores and/or mangrove trunks to vertically migrate above the water line or by retreating into its shell. We hypothesised that (1) B. auratum would display greater and more rapid vertical migration out of acidified than reference estuarine waters, and (2) responses would be more pronounced in gastropods collected from acidified than reference sites. Gastropods from acidified sites showed significantly higher activity in and more rapid migration out of acidified waters of pH 6.2-7.0, than reference waters or waters of pH < 5.0. Gastropods from reference locations showed a significantly weaker response to acidified water than those from acidified waters, and which did not significantly differ from their response to reference water. At extremely low pHs, <5.0, a higher proportion of both acidified and reference gastropods retreated into their shell than at higher pHs. Both the migration of gastropods out of acidified waters and retraction into their shells serves to reduce exposure time to acidified waters and may reduce the impact of this stressor on their populations. The stronger response to acidification of gastropods from populations previously exposed to this stressor suggests that the response may be learned, inherited or induced over multiple exposures. Our study adds to growing evidence that estuarine organisms may exhibit considerable physiological and behaviour adaptive capacity to acidification. The potential for such adaptive capacity should be incorporated into studies seeking to forecast impacts to marine organisms

  7. Dietary nitrates, nitrites, and cardiovascular disease.

    PubMed

    Hord, Norman G

    2011-12-01

    Dietary nitrate (NO(3)), nitrite (NO(2)), and arginine can serve as sources for production of NO(x) (a diverse group of metabolites including nitric oxide, nitrosothiols, and nitroalkenes) via ultraviolet light exposure to skin, mammalian nitrate/nitrite reductases in tissues, and nitric oxide synthase enzymes, respectively. NO(x) are responsible for the hypotensive, antiplatelet, and cytoprotective effects of dietary nitrates and nitrites. Current regulatory limits on nitrate intakes, based on concerns regarding potential risk of carcinogenicity and methemoglobinemia, are exceeded by normal daily intakes of single foods, such as soya milk and spinach, as well as by some recommended dietary patterns such as the Dietary Approaches to Stop Hypertension diet. This review includes a call for regulatory bodies to consider all available data on the beneficial physiologic roles of nitrate and nitrite in order to derive rational bases for dietary recommendations.

  8. Reduction of hexavalent chromium in water samples acidified for preservation

    USGS Publications Warehouse

    Stollenwerk, K.G.; Grove, D.B.

    1985-01-01

    Reduction of hexavalent chromium, Cr(VI), in water samples, preserved by standard techniques, was investigated. The standard preservation technique for water samples that are to be analyzed for Cr(VI) consists of filtration through a 0.45-??m membrane, acidification to a pH < 2, and storage in plastic bottles. Batch experiments were conducted to evaluate the effect of H+ concentration, NO2, temperature, and dissolved organic carbon (DOC) on the reduction of Cr(VI) to Cr(III). The rate of reduction of Cr(VI) to Cr(III) increased with increasing NO2, DOC, H+, and temperature. Reduction of Cr(VI) by organic matter occurred in some samples even though the samples were unacidified. Reduction of Cr(VI) is inhibited to an extent by storing the sample at 4??C. Stability of Cr(VI) in water is variable and depends on the other constituents present in the sample. Water samples collected for the determination of Cr(VI) should be filtered (0.45-??m membrane), refrigerated, and analyzed as quickly as possible. Water samples should not be acidified. Measurement of total Cr in addition to Cr(VI) can serve as a check for Cr(VI) reduction. If total Cr is greater than Cr(VI), the possibility that Cr(VI) reduction has occurred needs to be considered.The rate of reduction of Cr(VI) to Cr(III) increased with increasing NO//2, DOC, H** plus , and temperature. Reduction of Cr(VI) by organic matter occurred in some samples even though the samples were unacidified. Reduction of Cr(VI) is inhibited to an extent by storing the sample at 4 degree C. Stability of Cr(VI) in water is variable and depends on the other constituents present in the sample. Water samples collected for the determination of Cr(VI) should be filtered (0. 45- mu m membrane), refrigerated, and analyzed as quickly as possible. Water samples should not be acidified. Measurement of total Cr in addition to Cr(VI) can serve as a check for Cr(VI) reduction. If total Cr is greater than Cr(VI), the possibility that Cr

  9. Nitrite complexes of uranium and thorium.

    PubMed

    Dulong, Florian; Pouessel, Jacky; Thuéry, Pierre; Berthet, Jean-Claude; Ephritikhine, Michel; Cantat, Thibault

    2013-03-25

    The first examples of inorganic nitrite complexes of the natural actinides are described, including the structures of the homoleptic thorium(IV) [PPh(4)](2)[Th(NO(2))(6)] and the uranyl(VI) [PPh(4)](2)[UO(2)(NO(2))(4)] complexes; the nitrite ligand can adopt two different coordination modes in the coordination sphere of the uranyl ion and is unstable towards reduction.

  10. The Reaction between Nitrite and Oxyhemoglobin

    PubMed Central

    Keszler, Agnes; Piknova, Barbora; Schechter, Alan N.; Hogg, Neil

    2008-01-01

    The nitrite anion (NO–2) has recently received much attention as an endogenous nitric oxide source that has the potential to be supplemented for therapeutic benefit. One major mechanism of nitrite reduction is the direct reaction between this anion and the ferrous heme group of deoxygenated hemoglobin. However, the reaction of nitrite with oxyhemoglobin (oxyHb) is well established and generates nitrate and methemoglobin (metHb). Several mechanisms have been proposed that involve the intermediacy of protein-free radicals, ferryl heme, nitrogen dioxide (NO2), and hydrogen peroxide (H2O2) in an autocatalytic free radical chain reaction, which could potentially limit the usefulness of nitrite therapy. In this study we show that none of the previously published mechanisms is sufficient to fully explain the kinetics of the reaction of nitrite with oxyHb. Based on experimental data and kinetic simulation, we have modified previous models for this reaction mechanism and show that the new model proposed here is consistent with experimental data. The important feature of this model is that, whereas previously both H2O2 and NO2 were thought to be integral to both the initiation and propagation steps, H2O2 now only plays a role as an initiator species, and NO2 only plays a role as an autocatalytic propagatory species. The consequences of uncoupling the roles of H2O2 and NO2 in the reaction mechanism for the in vivo reactivity of nitrite are discussed. PMID:18203719

  11. Acute toxicity of ammonia and nitrite to shortnose sturgeon fingerlings

    USGS Publications Warehouse

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

    1998-01-01

    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).

  12. Effects of different nitrite concentrations from a vegetable source with and without high hydrostatic pressure on the recovery of Listeria monocytogenes on ready-to-eat restructured ham.

    PubMed

    Lavieri, Nicolas A; Sebranek, Joseph G; Cordray, Joseph C; Dickson, James S; Horsch, Ashley M; Jung, Stephanie; Manu, David K; Brehm-Stecher, Byron F; Mendonça, Aubrey F

    2014-05-01

    Sodium nitrite exerts an inhibitory effect on the growth of Listeria monocytogenes. The objective of this study was to investigate the effects of various nitrite concentrations from a vegetable source with and without high hydrostatic pressure (HHP) on the recovery and growth of L. monocytogenes on ready-to-eat restructured ham. A preconverted celery powder was used as the vegetable source of nitrite. Targeted concentrations of natural nitrite investigated were 0, 50, and 100 mg/kg. HHP treatments evaluated were 400 MPa for 4 min and 600 MPa for 1 or 4 min at 12 ± 2 °C (initial temperature of the pressurization fluid). Viable L. monocytogenes populations were monitored on modified Oxford medium and thin agar layer medium through 98 days of storage at 4 ± 1 °C. Populations on both media did not differ. The HHP treatment at 600 MPa for 4 min resulted in L. monocytogenes populations below the detection limit of our sampling protocols throughout the storage period regardless of the natural nitrite concentration. The combination of HHP at 400 MPa for 4 min or 600 MPa for 1 min with natural nitrite resulted in initial inhibition of viable L. monocytogenes. Ham formulations that did not contain natural nitrite allowed faster growth of L. monocytogenes than did those with nitrite, regardless of whether they were treated with HHP. The results indicate that nitrite from a vegetable source at the concentrations used in this study resulted in slower growth of this microorganism. HHP treatments enhanced the inhibitory effects of natural nitrite on L. monocytogenes growth. Thus, the combination of natural nitrite plus HHP appears to have a synergistic inhibitory effect on L. monocytogenes growth.

  13. Nitrite-catalase interaction as an important element of nitrite toxicity.

    PubMed

    Titov, V Yu; Petrenko, Yu M

    2003-06-01

    It was established that nitrite in the presence of chloride, bromide, and thiocyanate decreases the rate of hydrogen peroxide decomposition by catalase. The decrease was recorded by the permanganatometric method and by a method of dynamic calorimetry. Nitrite was not destroyed in the course of the reaction and the total value of heat produced in the process was not changed by its presence. These facts suggest that nitrite induces inhibition of catalase with no change in the essence of the enzymatic process. Even micromolar nitrite concentrations induced a considerable decrease in catalase activity. However, in the absence of chloride, bromide, and thiocyanate inhibition was not observed. In contrast, fluoride protected catalase from nitrite inhibition in the presence of the above-mentioned halides and pseudohalide. As hydrogen peroxide is a necessary factor for triggering a number of important toxic effects of nitrite, the latter increases its toxicity by inhibiting catalase. This was shown by the example of nitrite-induced hemoglobin oxidation. The naturally existing gradient of chloride and other anion concentrations between intra- and extracellular media appears to be the most important mechanism of cell protection from inhibition of intracellular catalase by nitrite. Possible mechanisms of this inhibition are discussed.

  14. Nitrite dismutase reaction mechanism: kinetic and spectroscopic investigation of the interaction between nitrophorin and nitrite.

    PubMed

    He, Chunmao; Howes, Barry D; Smulevich, Giulietta; Rumpel, Sigrun; Reijerse, Edward J; Lubitz, Wolfgang; Cox, Nicholas; Knipp, Markus

    2015-04-01

    Nitrite is an important metabolite in the physiological pathways of NO and other nitrogen oxides in both enzymatic and nonenzymatic reactions. The ferric heme b protein nitrophorin 4 (NP4) is capable of catalyzing nitrite disproportionation at neutral pH, producing NO. Here we attempt to resolve its disproportionation mechanism. Isothermal titration calorimetry of a gallium(III) derivative of NP4 demonstrates that the heme iron coordinates the first substrate nitrite. Contrary to previous low-temperature EPR measurements, which assigned the NP4-nitrite complex electronic configuration solely to a low-spin (S = 1/2) species, electronic absorption and resonance Raman spectroscopy presented here demonstrate that the NP4-NO2(-) cofactor exists in a high-spin/low-spin equilibrium of 7:3 which is in fast exchange in solution. Spin-state interchange is taken as evidence for dynamic NO2(-) coordination, with the high-spin configuration (S = 5/2) representing the reactive species. Subsequent kinetic measurements reveal that the dismutation reaction proceeds in two discrete steps and identify an {FeNO}(7) intermediate species. The first reaction step, generating the {FeNO}(7) intermediate, represents an oxygen atom transfer from the iron bound nitrite to a second nitrite molecule in the protein pocket. In the second step this intermediate reduces a third nitrite substrate yielding two NO molecules. A nearby aspartic acid residue side-chain transiently stores protons required for the reaction, which is crucial for NPs' function as nitrite dismutase.

  15. Levels of Nitrates and Nitrites in Chili Pepper and Ventricina Salami

    PubMed Central

    Piccirilli, Michele; Iafigliola, Luigi; Amadoro, Carmela

    2014-01-01

    Ventricina is a traditional sausage made from pork meat produced in the Abruzzi and Molise regions. The aim of this study was to detect the content of nitrates and nitrites in local cultivars of chilli pepper, and their concentration in ventricina samples spiced with the same chilli pepper. Furthermore, it was examined whether, in the samples of ventricina with nitrate addition, the spicing with chilli pepper could exceed the maximum added dose. The concentration of nitrates and nitrites in the organic chilli pepper was 531.0±94.6 mg/kg and less than 5.0 mg, respectively, in the traditional chilli pepper it was 394.0±39.6 and less than 5.0 mg, while in the commercial it was 325.0±115.0 and less than 5.0 mg. The determination of nitrites and nitrates was carried out by high performance ion chromatography. In ventricina samples produced without added sodium nitrate, nitrates and nitrites were below 5.0 mg/kg at the case-filling time (t0) and after 50 days of aging (t50). In the samples of ventricina with added sodium nitrate, nitrate concentration values were 134.0±20.9 mg/kg at t0 and 129.0±15.4 mg/kg at t50, while the nitrites were below 5.0 mg/kg at t0 and 28.8±15.8 mg/kg at t50. Although in ventricina the amount of chilli pepper is quite relevant, it did not lead to a detectable concentration of nitrates. The maximum allowed amount was never exceeded. PMID:27800331

  16. The Nitrite-Scavenging Properties of Catechol, Resorcinol, and Hydroquinone: A Comparative Study on Their Nitration and Nitrosation Reactions.

    PubMed

    Lu, Yunhao; Dong, Yanzuo; Li, Xueli; He, Qiang

    2016-10-14

    The nitration and nitrosation reactions of catechol, resorcinol, and hydroquinone (0.05 mmol/L) with sodium nitrite (0.05 mmol/L) at pH 3 and 37 °C were studied by using liquid chromatography and mass spectrometry (LC-MS) and atom charge analysis, which was aimed to provide chemical insight into the nitrite-scavenging behavior of polyphenols. The 3 benzenediols showed different mechanisms to scavenge nitrite due to their differences in hydroxyl position. Catechol was nitrated with 1 NO2 group at the hydroxyl oxygen, and resorcinol was nitrosated with 2 NO groups at the C2 and C4 (or C6 ) positions of the benzene ring. Hydroquinone could scavenge nitrite through both nitration and nitrosation mechanisms. The nitrated hydroquinone had 1 NO2 group at the hydroxyl oxygen in the molecule, while the nitrosated 1 containing 2 NO groups at the benzene ring might have 3 structure probabilities. The results may provide a structure-activity understanding on the nitrite-scavenging property of polyphenols, so as to promote their application in the food industry for the removal of possibly toxic nitrites found in many vegetables and often in processed meat products.

  17. Role of nitrite in regulation of fetal cephalic circulation in sheep.

    PubMed

    Truong, Giang T; Schröder, Hobe J; Liu, Taiming; Zhang, Meijuan; Kanda, Eriko; Bragg, Shannon; Power, Gordon G; Blood, Arlin B

    2014-04-15

    Nitrite has been postulated to provide a reservoir for conversion to nitric oxide (NO), especially in tissues with reduced oxygen levels as in the fetus. Nitrite would thus provide local vasodilatation and restore a balance between oxygen supply and need, a putative mechanism of importance especially in the brain. The current experiments test the hypothesis that exogenous nitrite acts as a vasodilator in the cephalic vasculature of the intact, near term fetal sheep. Fetuses were first instrumented to measure arterial blood pressure and carotid artery blood flow and then studied 4-5 days later while in utero without anaesthesia. Initially l-nitro-arginine (LNNA) was given to block endogenous NO production. Carotid resistance to flow increased 2-fold from 0.54 ± 0.01 (SEM) to 1.20 ± 0.08 mmHg min ml(-1) (in 13 fetuses, P < 0.001), indicating NO tonically reduces cerebral vascular tone. Sodium nitrite (or saline as control) was then infused in increasing step-doses from 0.01 to 33 μm in half-log increments over a period of 2 h. Carotid artery pressure, blood flow and vascular resistance did not change compared to fetuses receiving saline, even at plasma nitrite concentrations two orders of magnitude above the physiological range. The results indicate that while cephalic vascular tone is controlled by endogenous nitric oxide synthase activity, exogenously administered nitrite is not a vasodilator at physiological concentrations in the vasculature served by the carotid artery of fetal sheep.

  18. Elevated Colonization of Microborers at a Volcanically Acidified Coral Reef

    PubMed Central

    Enochs, Ian C.; Manzello, Derek P.; Tribollet, Aline; Valentino, Lauren; Kolodziej, Graham; Donham, Emily M.; Fitchett, Mark D.; Carlton, Renee; Price, Nichole N.

    2016-01-01

    Experiments have demonstrated that ocean acidification (OA) conditions projected to occur by the end of the century will slow the calcification of numerous coral species and accelerate the biological erosion of reef habitats (bioerosion). Microborers, which bore holes less than 100 μm diameter, are one of the most pervasive agents of bioerosion and are present throughout all calcium carbonate substrates within the reef environment. The response of diverse reef functional groups to OA is known from real-world ecosystems, but to date our understanding of the relationship between ocean pH and carbonate dissolution by microborers is limited to controlled laboratory experiments. Here we examine the settlement of microborers to pure mineral calcium carbonate substrates (calcite) along a natural pH gradient at a volcanically acidified reef at Maug, Commonwealth of the Northern Mariana Islands (CNMI). Colonization of pioneer microborers was higher in the lower pH waters near the vent field. Depth of microborer penetration was highly variable both among and within sites (4.2–195.5 μm) over the short duration of the study (3 mo.) and no clear relationship to increasing CO2 was observed. Calculated rates of biogenic dissolution, however, were highest at the two sites closer to the vent and were not significantly different from each other. These data represent the first evidence of OA-enhancement of microboring flora colonization in newly available substrates and provide further evidence that microborers, especially bioeroding chlorophytes, respond positively to low pH. The accelerated breakdown and dissolution of reef framework structures with OA will likely lead to declines in structural complexity and integrity, as well as possible loss of essential habitat. PMID:27467570

  19. Effects of organic tomato pulp powder and nitrite level on the physicochemical, textural and sensory properties of pork luncheon roll.

    PubMed

    Hayes, J E; Canonico, I; Allen, P

    2013-11-01

    Nine treatments of pork luncheon roll produced with three sodium nitrite levels (0, 0.05 and 0.1%) and three tomato pulp powder (TPP) levels (0, 1.5 and 3%) were assessed at three storage times (2, 7 and 14d). The effects of enrichment with TPP on composition (protein, fat, moisture and ash), pH, colour (CIE L*, a*, b*), nitrosomyoglobin (NOMb) content, lipid oxidation (TBARS), residual nitrite content, total viable count (TVC) texture profile analysis (TPA) and sensory analysis of cooked pork luncheon roll were investigated. Decreasing the level of nitrite increased (p<0.001) the pH, the NOMb value (p<0.001), lipid oxidation (p<0.001) and the residual nitrite content (p<0.001) and affected the colour of the cooked product. The reduction in nitrites had no effect on the composition and texture of the pork luncheon rolls. Adding TPP reduced (p<0.001) the pH and increased (p<0.001) the colour parameters a* and b* of both the raw luncheon roll formulation and the cooked luncheon roll product. TPP, particularly at 3% had a detrimental effect on the texture of pork luncheon rolls by decreasing hardness (p<0.001), gumminess (p<0.001) and chewiness (p<0.001) and increasing cohesiveness (p<0.001). The TBA value increased (p<0.01) with the three main factors (nitrite, TPP, day) but was in all cases well below the 2mg MDA/kg threshold. TVCs for all treatments and storage days were below the TVC limit for this type of cooked product. The pork luncheon roll formulated with 50mg nitrite and 1.5% TPP had similar or enhanced sensory attributes compared to the luncheon roll containing no TPP and a nitrite level of 100mg/kg of product.

  20. Mechanisms of nitrite addition for simultaneous sludge fermentation/nitrite removal (SFNR).

    PubMed

    Wu, Chengcheng; Peng, Yongzhen; Wang, Shuying; Li, Baikun; Zhang, Liang; Cao, Shenbin; Du, Rui

    2014-11-01

    Simultaneous sludge fermentation and nitrite removal (SFNR) was investigated as a novel sludge/wastewater treatment process with high nitrogen concentrations. The results showed that introducing nitrite improved the primary sludge (PS) fermentation system by improving the chemical oxygen demand (COD) yields and the volatile suspend solid (VSS) reduction. At a nitrite dosage of 0.2 g g SS(-1), the COD production was 1.02 g g VSS(-1) and the VSS reduction was 63.4% within 7-day fermentation, while the COD production was only 0.17 g g VSS(-1) and the VSS reduction was only 4.9% in the blank test. Nitrite contained in wastewater was removed through denitrification process in the SFNR system. The solubility of carbohydrate and protein was substantially enhanced, and their contents reached the peak once nitrite was consumed. In addition, the nutrient release and methane generation were inhibited in the SFNR system, which alleviated the environmental pollution. Unlike traditional fermentation systems, neither alkaline condition nor high free nitrite acid (FNA) concentration affected the PS fermentation in the SFNR system. Molecular weight distribution (MWD) and Live/Dead cell analysis indicated that the sludge disruption by nitrite and the consumption of soluble organic substances in sludge might play important roles in SFNR.

  1. A nitrite transporter associated with nitrite uptake by higher plant chloroplasts.

    PubMed

    Sugiura, Miwa; Georgescu, Mihaela N; Takahashi, Masaaki

    2007-07-01

    Chloroplasts take up cytosolic nitrite during nitrate assimilation. In this study we identified a nitrite transporter located in the chloroplasts of higher plants. The transporter, CsNitr1-L, a member of the proton-dependent oligopeptide transporter (POT) family, was detected during light-induced chloroplast development in de-etiolating cucumber seedlings. We detected a CsNitr1-L-green fluorescent protein (GFP) fusion protein in the chloroplasts of leaf cells and found that an immunoreactive 51 kDa protein was present in the isolated inner envelope membrane of chloroplasts. CsNitr1-L has an isoform, CsNitr1-S, with an identical 484 amino acid core sequence; however, in CsNitr1-S the 120 amino acid N-terminal extension is missing. Saccharomyces cerevisiae cells expressing CsNitr1-S absorbed nitrite from an acidic medium at a slower rate than mock-transformed control cells, and accumulated nitrite to only one-sixth the concentration of the control cells, suggesting that CsNitr1-S enhances the efflux of nitrite from the cell. Insertion of T-DNA in a single CsNitr1-L homolog (At1g68570) in Arabidopsis resulted in nitrite accumulation in leaves to more than five times the concentration found in the wild type. These results show that it is possible that both CsNitr1-L and CsNitr1-S encode efflux-type nitrite transporters, but with different subcellular localizations. CsNitr1-L may possibly load cytosolic nitrite into chloroplast stroma in the chloroplast envelope during nitrate assimilation. The presence of genes homologous to CsNitr1-L in the genomes of Arabidopsis and rice indicates that facilitated nitrite transport is of general physiological importance in plant nutrition.

  2. Mechanism of reaction of myeloperoxidase with nitrite.

    PubMed

    Burner, U; Furtmuller, P G; Kettle, A J; Koppenol, W H; Obinger, C

    2000-07-07

    Myeloperoxidase (MPO) is a major neutrophil protein and may be involved in the nitration of tyrosine residues observed in a wide range of inflammatory diseases that involve neutrophils and macrophage activation. In order to clarify if nitrite could be a physiological substrate of myeloperoxidase, we investigated the reactions of the ferric enzyme and its redox intermediates, compound I and compound II, with nitrite under pre-steady state conditions by using sequential mixing stopped-flow analysis in the pH range 4-8. At 15 degrees C the rate of formation of the low spin MPO-nitrite complex is (2.5 +/- 0.2) x 10(4) m(-1) s(-1) at pH 7 and (2.2 +/- 0.7) x 10(6) m(-1) s(-1) at pH 5. The dissociation constant of nitrite bound to the native enzyme is 2.3 +/- 0.1 mm at pH 7 and 31.3 +/- 0.5 micrometer at pH 5. Nitrite is oxidized by two one-electron steps in the MPO peroxidase cycle. The second-order rate constant of reduction of compound I to compound II at 15 degrees C is (2.0 +/- 0.2) x 10(6) m(-1) s(-1) at pH 7 and (1.1 +/- 0.2) x 10(7) m(-1) s(-1) at pH 5. The rate constant of reduction of compound II to the ferric native enzyme at 15 degrees C is (5.5 +/- 0.1) x 10(2) m(-1) s(-1) at pH 7 and (8.9 +/- 1.6) x 10(4) m(-1) s(-1) at pH 5. pH dependence studies suggest that both complex formation between the ferric enzyme and nitrite and nitrite oxidation by compounds I and II are controlled by a residue with a pK(a) of (4.3 +/- 0.3). Protonation of this group (which is most likely the distal histidine) is necessary for optimum nitrite binding and oxidation.

  3. 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 ...

  4. 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...

  5. Nitrite inhibition of denitrification by Pseudomonas fluorescens

    SciTech Connect

    Almeida, J.S.; Julio, S.M.; Reis, M.A.M. |

    1995-05-05

    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.

  6. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Products and nitrates and nitrites... and nitrates and nitrites. Any product, such as frankfurters and corned beef, for which there is a standard in this part and to which nitrate or nitrite is permitted or required to be added, may be...

  7. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Products and nitrates and nitrites... and nitrates and nitrites. Any product, such as frankfurters and corned beef, for which there is a standard in this part and to which nitrate or nitrite is permitted or required to be added, may be...

  8. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Products and nitrates and nitrites... and nitrates and nitrites. Any product, such as frankfurters and corned beef, for which there is a standard in this part and to which nitrate or nitrite is permitted or required to be added, may be...

  9. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Products and nitrates and nitrites... and nitrates and nitrites. Any product, such as frankfurters and corned beef, for which there is a standard in this part and to which nitrate or nitrite is permitted or required to be added, may be...

  10. 9 CFR 319.2 - Products and nitrates and nitrites.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Products and nitrates and nitrites... and nitrates and nitrites. Any product, such as frankfurters and corned beef, for which there is a standard in this part and to which nitrate or nitrite is permitted or required to be added, may be...

  11. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  12. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  13. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  14. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  15. 40 CFR 721.4740 - Alkali metal nitrites.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in...

  16. Trace metal biogeochemistry in mangrove ecosystems: a comparative assessment of acidified (by acid sulfate soils) and non-acidified sites.

    PubMed

    Nath, Bibhash; Birch, Gavin; Chaudhuri, Punarbasu

    2013-10-01

    The generation of acidity and subsequent mobilization of toxic metals induced by acid sulfate soils (ASSs) are known to cause severe environmental damage to many coastal wetlands and estuaries of Australia and worldwide. Mangrove ecosystems serve to protect coastal environments, but are increasingly threatened from such ASS-induced acidification due to variable hydrological conditions (i.e., inundation-desiccation cycles). However, the impact of such behaviors on trace metal distribution, bio-availability and accumulation in mangrove tissues, i.e., leaves and pneumatophores, are largely unknown. In this study, we examined how ASS-induced acidifications controlled trace metal distribution and bio-availability in gray mangrove (Avicennia marina) soils and in tissues in the Kooragang wetland, New South Wales, Australia. We collected mangrove soils, leaves and pneumatophores from a part of the wetland acidified from ASS (i.e., an affected site) for detailed biogeochemical studies. The results were compared with samples collected from a natural intertidal mangrove forest (i.e., a control site) located within the same wetland. Soil pH (mean: 5.90) indicated acidic conditions in the affected site, whereas pH was near-neutral (mean: 7.17) in the control site. The results did not show statistically significant differences in near-total and bio-available metal concentrations, except for Fe and Mn, between affected and control sites. Iron concentrations were significantly (p values≤0.001) greater in the affected site, whereas Mn concentrations were significantly (p values≤0.001) greater in the control site. However, large proportions of near-total metals were potentially bio-available in control sites. Concentrations of Fe and Ni were significantly (p values≤0.001) greater in leaves and pneumatophores of the affected sites, whereas Mn, Cu, Pb and Zn were greater in control sites. The degree of metal bio-accumulation in leaves and pneumatophores suggest contrasting

  17. Lactoferrin and transferrin fragments react with nitrite to form an inhibitor of Bacillus cereus spore outgrowth.

    PubMed Central

    Custer, M C; Hansen, J N

    1983-01-01

    Tryptone is a pancreatic digest of casein which contains a heterogeneous mixture of substances that react with nitrite when heated in the presence of sodium thioglycolate to form a bacteriostatic agent which inhibits outgrowth of Bacillus cereus T spores. The substances which are precursors to the bacteriostatic agent can be fractionated on the basis of molecular size and charge and have properties which indicate that they are fragments of lactoferrin, an iron-binding glycoprotein. The bacteriostatic agent could also be formed directly from purified lactoferrin after it had been subjected to proteolysis. Transferrin, an analogous iron-binding protein found in animal serum, also showed these same properties. This system may be a useful model for studies of the mechanism and site of nitrite bacteriostatic action. PMID:6405692

  18. A Novel Nanofilm Sensor Based on Poly-(Alizarin Red)/Fe3O4 Magnetic Nanoparticles-Multiwalled Carbon Nanotubes Composite Material for Determination of Nitrite.

    PubMed

    Qu, Jianying; Dong, Ying; Yong, Wang; Lou, Tongfang; Du, Xueping; Qu, Jianhang

    2016-03-01

    Fe3O4 magnetic nanoparticles were synthesized by chemical co-precipitation with sodium citrate as surfactant and were characterized by FT-IR spectrometer, X-ray diffraction and transmission electron microscopy. A novel nitrite sensor was fabricated by electropolymerization of alizarin red on the surface of glassy carbon electrode modified with Fe3O4-multiwalled carbon nanotubes composite nanofilm. Under the optimal experimental conditions, it was showed that the proposed sensor exhibited good electrocatalytic activity to the oxidation of nitrite, and the peak current increased linearly with the nitrite concentration from 9.64 x 10(-6) mol x L(-1) to 1.30 x 10(-3) mol x L(-1) (R = 0.9976) with a detection limit of 1.19 x 10(-6) mol x L(-1) (S/N = 3). This sensor showed excellent sensitivity, wide linear range, stability and repeatability for nitrite determination with potential applications.

  19. Analysis of Trace VX in Acidified VX Hydrolysate Samples

    DTIC Science & Technology

    2009-07-01

    reformation. 2. EXPERIMENTAL PROCEDURES 2.1 Materials Tribasic potassium phosphate (K3P04, >98%, lot 097K0010), sodium carbonate (Na2C03, lot...reservoir was removed. Any water droplets in the cartridge were removed with a disposable pipet. n. VX was eluted by adding 2 ml_ of 90:10...Column temperature 50-200 °C (5 min) @ 20 °C /min; 200-230 °C @ 3 °C /min; 230-260 °C @ 30 °C/min; post-run 260 °C (7 min) Carrier gas Helium

  20. Effect of sodium chloride, sodium nitrite and temperature on desorption isotherms of previously frozen beef.

    PubMed

    Kabil, Emre; Aktaş, Nesimi; Balcı, Ercan

    2012-04-01

    Moisture desorption isotherms of beef were determined in the relative humidity range of 23 to 90% at 5, 15 and 25°C and at 2.5% NaCl and 2.5% NaCl+150 ppm NaNO(2) content. Desorption isotherms were found to be typical type II sigmoid. The water content at equilibrium was higher in beef with NaCl and NaCl+NaNO(2) than control samples. Experimental data were fitted to various mathematical models and it was found that the Peleg model was best in describing the equilibrium moisture content relationship for beef samples over the entire range of temperatures. The net isosteric heat of sorption was estimated from equilibrium desorption data, using the Clausius-Clapeyron equation. Isosteric heats of desorption were found to increase with decreasing moisture content.

  1. Combined exposure to ambient UVB radiation and nitrite negatively affects survival of amphibian early life stages.

    PubMed

    Macías, Guadalupe; Marco, Adolfo; Blaustein, Andrew R

    2007-10-15

    Many aquatic species are sensitive to ambient levels of ultraviolet-B radiation (UVB) and chemical fertilizers. However, recent studies indicate that the interaction among multiple stressors acting simultaneously could be contributing to the population declines of some animal species. Therefore, we tested the potential synergistic effects between ambient levels of UVB and a contaminant, sodium nitrite in the larvae of two amphibian species, the common European toad Bufo bufo and the Iberian green frog Rana perezi. We studied R. perezi from both mountain and coastal populations to examine if populations of the same species varied in their response to stressors in different habitats. Both species were sensitive to the two stressors acting alone, but the interaction between the two stressors caused a multiplicative impact on tadpole survival. For B. bufo, the combination of UVB and nitrite was up to seven times more lethal than mortality for each stressor alone. In a coastal wetland, the combination of UVB and nitrite was four times more toxic for R. perezi than the sum of the effect on mortality for each stressor alone. One mg/L of nitrite killed half the population of R. perezi at Gredos Mountains at day 10 in the absence of UVB. In the presence of UVB, 50% of the tadpoles from the same experiment died at day 7. Similar toxic response were found for R. perezi in two highly contrasted environments suggesting this synergistic interaction can be a widespread phenomenon. The interaction of excess chemical fertilizers and manure with ambient UVB radiation could be contributing to the global decline of some amphibian species. We suggest that potential exposure to UVB radiation be accounted for when assessing water quality criteria regarding nitrite pollution.

  2. The effects of four acidifying sprays, vinegar, and water on canine cutaneous pH levels.

    PubMed

    Matousek, Jennifer L; Campbell, Karen L; Kakoma, Ibulaimu; Schaeffer, David J

    2003-01-01

    This study determined the extent and duration of cutaneous acidification caused by a single application of four acidifying sprays, vinegar, and water. Multivariate repeated measures analysis of variance revealed a significant difference between the six sprays (F = 15.3; P < or = 0.001). Linear contrast tests showed that the effects of the acidifying sprays were significantly different from vinegar and water (F = 6.0; P < or = 0.001), and vinegar was significantly different from water (F = 13.8; P < or = 0.001). The acidifying sprays decreased cutaneous pH to < 6.0 for a mean range of 50 to 65 hours, while vinegar did so for a mean of 12 hours.

  3. Nutrient cycling and the growth of benthic algae in experimentally acidified Little Rock Lake, WI

    SciTech Connect

    Detenbeck, N.E.

    1987-01-01

    Changes in nutrient-cycling and the growth of benthic algae resulting from decreased pH in low alkalinity lake systems were analyzed by laboratory, mesocosm, and whole-lake studies on Little Rock Lake, Wisconsin. Nutrients, transparency, an algal growth in the experimentally acidified basin were compared with conditions in an untreated reference basin. During the first summer following acidification (1985), accumulation rates of attached algae were significantly higher in the acidified basin than in the reference basin during June-August, but not in September. Color and winter silica values were significantly lower in the acidified basin relative to the reference basin following treatment. In addition, the lack of a fall decline in SiO/sub 2/ in the north basin in 1986 may signal pH-related changes in siliceous algal communities.

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

    SciTech Connect

    Lambertin, D.; Chartier, D.; Joussot-Dubien, C.

    2007-07-01

    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)

  5. Effect of feeding nitrite, ascorbate, hemin, and omeprazole on excretion of fecal total apparent N-nitroso compounds in mice.

    PubMed

    Mirvish, Sidney S; Davis, Michael E; Lisowyj, Michal P; Gaikwad, Nilesh W

    2008-12-01

    It was proposed that colon cancer induced by red and nitrite-preserved meat is due to meat-derived N-nitroso compounds in the colonic contents. To explore this view, we previously showed that feeding beef and hot dogs increased the fecal output of total apparent N-nitroso compounds (ANC) in mice. In the current project, adult Swiss mice were fed a semipurified diet and water containing additives for 7 days. Feces from individual mice was collected on day 7, dried, and extracted with water. Extracts were analyzed for ANC as before. Feeding 2.0 g sodium nitrite (NaNO2)/L drinking water raised fecal ANC levels from 5 to 63 nmol/g feces. In a dose-response study, fecal ANC levels were proportional to the nitrite concentration squared. Even 32 mg NaNO2/L raised fecal ANC levels 2.3-fold (P < 0.05). In other results, 64, 125, and 250 mg hemin/kg diet, fed with 2 g NaNO2/L water, showed 2.3, 2.2, and 4.6 times the ANC level for nitrite alone. Sodium nitrate (12 g/L water) did not affect fecal ANC output. Omeprazole (400 mg/kg diet) and sodium ascorbate (23 g/kg diet), when fed with 1 g NaNO2/L water, lowered fecal ANC levels by 65 and 41%, indicating that, when nitrite was fed, acid-catalyzed reactions in the stomach produced ANC, which passed down the gut to the feces. Tests indicated that nitrosothiols constituted about 20% of fecal and hot dog ANC. The observed effect of NaNO2 is thus far not consistent with the proposed hypothesis. The enhancement by hemin may help explain why red meat is a cause of colon cancer.

  6. Heme-induced biomarkers associated with red meat promotion of colon cancer are not modulated by the intake of nitrite.

    PubMed

    Chenni, Fatima Z; Taché, Sylviane; Naud, Nathalie; Guéraud, Françoise; Hobbs, Ditte A; Kunhle, Gunter G C; Pierre, Fabrice H; Corpet, Denis E

    2013-01-01

    Red and processed meat consumption is associated with the risk of colorectal cancer. Three hypotheses are proposed to explain this association, via heme-induced oxidation of fat, heterocyclic amines, or N-nitroso compounds. Rats have often been used to study these hypotheses, but the lack of enterosalivary cycle of nitrate in rats casts doubt on the relevance of this animal model to predict nitroso- and heme-associated human colon carcinogenesis. The present study was thus designed to clarify whether a nitrite intake that mimics the enterosalivary cycle can modulate heme-induced nitrosation and fat peroxidation. This study shows that, in contrast with the starting hypothesis, drinking water added with nitrite to mimic the salivary nitrite content did not change the effect of hemoglobin on biochemical markers linked to colon carcinogenesis, notably lipid peroxidation and cytotoxic activity in the colon of rat. However, ingested sodium nitrite increased fecal nitroso-compounds level, but their fecal concentration and their nature (iron-nitrosyl) would probably not be associated with an increased risk of cancer. We thus suggest that the rat model could be relevant for study the effect of red meat on colon carcinogenesis, in spite of the lack of nitrite in the saliva of rats.

  7. Nitrite inhalants: history, epidemiology, and possible links to AIDS.

    PubMed Central

    Haverkos, H W; Kopstein, A N; Wilson, H; Drotman, P

    1994-01-01

    Nitrite inhalants have been commonly abused substances in the United States. Nitrite inhalants and AIDS was a popular topic in the early 1980s, when the cause of AIDS was not known. With the discovery of HIV, concern about nitrite use in the USA waned. However, nitrite inhalant use is associated with behavioral relapse and HIV transmission among gay men, with decreased lymphocyte counts and natural killer cell activity in a few laboratory studies, and it remains a candidate cofactor in the pathogenesis of AIDS-related Kaposi's sarcoma. Discouraging nitrite use continues to be a worthwhile public health goal. PMID:9644194

  8. Caustic-Side Solvent Extraction: Anti-Caking Surfactants Found to be Cause of Apparent Effect of High Nitrite Concentration on Cesium Stripping

    SciTech Connect

    Delmau, L.H.

    2002-06-13

    Experiments conducted in FY01 previously indicated a potential cesium stripping problem in the CSSX process due to the presence of nitrite in the waste simulant. The stripping issue seemed all the more important as the nitrite concentration increased. Experiments presented in this work have demonstrated that the true reason for the cesium stripping problem was in fact the presence of an anti-caking agent in the,sodium nitrite. used for the preparation of the simulants. The anti-caking agent is actually a mixture of well-known surfactants, sodium mono- and di-methyl naphthalene sulfonate that can partition into the organic-phase on extraction, then retain cesium upon stripping. The effect was demonstrated by adding known amounts of the anti-caking agent to clean systems. Data suggest that rejuvenation of the solvent can be obtained by a caustic wash following the stripping stage.

  9. Nitrites derived from Foneiculum vulgare (fennel) seeds promotes vascular functions.

    PubMed

    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

    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.

  10. Modification of membrane sulfhydryl groups in bacteriostatic action of nitrite

    SciTech Connect

    Buchman, G.W. III; Hansen, J.N.

    1987-01-01

    The mechanism by which nitrite inhibits outgrowing spores of bacillus cereus T was examined by using techniques developed earlier for nitrite analogs. The morphological stage of inhibition, cooperativity effects, effect of pH on inhibition, kinetics of protection against tritiated iodoacetate incorporation into membrane sulfhydryl groups, and protection against the bacteriocidal effect of carboxymethylation of iodoacetate indicate that nitrite acts as a membrane-directed sulfhydryl agent. The mechanism by which nitrite modifies the chemical reactivity of the sulfhyrdyl group could be either direct covalent modification or inactivation through communication with another modified membrane component. Profiles of pH effects suggest that the active agent is the protonated form of nitrite. The nitrite concentrations which modify membrane sulfhydryl activity coincide with those which have a bacteriostatic effect. These results are consistent with membrane sulfhydryl modification as a component of the mechanism of nitrite-induced bacteriostasis in this aerobic sporeformer.

  11. Influence of dietary nitrate on nitrite level of human saliva

    SciTech Connect

    Cingi, M.I.; Cingi, C.; Cingi, E. )

    1992-01-01

    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.

  12. Sodium Test

    MedlinePlus

    ... AACC products and services. Advertising & Sponsorship: Policy | Opportunities Sodium Share this page: Was this page helpful? Also known as: Na Formal name: Sodium Related tests: Chloride , Bicarbonate , Potassium , Electrolytes , Osmolality , Basic ...

  13. Sodium Oxybate

    MedlinePlus

    Sodium oxybate is used to prevent attacks of cataplexy (episodes of muscle weakness that begin suddenly and ... urge to sleep during daily activities, and cataplexy). Sodium oxybate is in a class of medications called ...

  14. Sodium - blood

    MedlinePlus

    ... naproxen Lower than normal sodium level is called hyponatremia. It may be due to: Use of medicines ... overview Hepatorenal syndrome Hyperaldosteronism - primary and secondary Hypopituitarism Hypothyroidism Ions Low sodium level Nephrotic syndrome Sweating Review ...

  15. Nitrite controls the release of nitric oxide in Pseudomonas aeruginosa cd{sub 1} nitrite reductase

    SciTech Connect

    Rinaldo, Serena; Brunori, Maurizio; Cutruzzola, Francesca

    2007-11-23

    Nitrite reductase (cd{sub 1}NIR) from Pseudomonas aeruginosa, which catalyses the reduction of nitrite to nitric oxide (NO), contains a c-heme as the electron acceptor and a d{sub 1}-heme where catalysis occurs. Reduction involves binding of nitrite to the reduced d{sub 1}-heme, followed by dehydration to yield NO; release of NO and re-reduction of the enzyme close the cycle. Since NO is a powerful inhibitor of ferrous hemeproteins, enzymatic turnover demands the release of NO. We recently discovered that NO dissociation from the ferrous d{sub 1}-heme is fast, showing that cd{sub 1}NIR behaves differently from other hemeproteins. Here we demonstrate for the first time that the physiological substrate nitrite displaces NO from the ferrous enzyme, which enters a new catalytic cycle; this reaction depends on the conserved His369 whose role in substrate stabilization is crucial for catalysis. Thus we suggest that also in vivo the activity of cd{sub 1}NIR is controlled by nitrite.

  16. Effect of pH and nitrite concentration on nitrite oxidation rate.

    PubMed

    Jiménez, E; Giménez, J B; Ruano, M V; Ferrer, J; Serralta, J

    2011-10-01

    The effect of pH and nitrite concentration on the activity of the nitrite oxidizing bacteria (NOB) in an activated sludge reactor has been determined by means of laboratory batch experiments based on respirometric techniques. The bacterial activity was measured at different pH and at different total nitrite concentrations (TNO₂). The experimental results showed that the nitrite oxidation rate (NOR) depends on the TNO₂ concentration independently of the free nitrous acid (FNA) concentration, so FNA cannot be considered as the real substrate for NOB. NOB were strongly affected by low pH values (no activity was detected at pH 6.5) but no inhibition was observed at high pH values (activity was nearly the same for the pH range 7.5-9.95). A kinetic expression for nitrite oxidation process including switch functions to model the effect of TNO₂ concentration and pH inhibition is proposed. Substrate half saturation constant and pH inhibition constants have been obtained.

  17. [Study the restoration technology of concentrated application-natural diffusion about amendments of acidified soil of hilly woodland].

    PubMed

    Fang, Xiong; Liu, Ju-Xiu; Yin, Guang-Cai; Zhao, Liang; Liu, Shi-Zhong; Chu, Guo-Wei; Li, Yi-Yong

    2013-01-01

    Through concentrated application of lime, sewage sludge and lime + sewage sludge on the sloping top of the hilly woodlands, the restoration effects of the three soil amendments on the acidified soil of hilly woodland were studied. The results showed that: (1) Joint application of sewage sludge + lime can significantly (P < 0.05) decrease soil acidity, promote the rapid increase in soil organic matter and nitrogen content, increase soil cation exchange capacity, and effectively improve acidified soil. (2) Through natural diffusion mechanisms of surface and subsurface runoff, a large area of acidified soil of hilly woodlands can be restored by concentrated application of soil amendments on the sloping top of the hilly woodlands. (3) It is conducive to solve the pollution problems of the urban sewage sludge by using municipal sewage sludge to restore acidified soil, but only for the restoration of acidified soil of timber forest.

  18. Nitrite in feed: From Animal health to human health

    SciTech Connect

    Cockburn, Andrew; Brambilla, Gianfranco; Fernández, Maria-Luisa; Arcella, Davide; Peteghem, Carlos van; Dorne, Jean-Lou

    2013-08-01

    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 been shown to contain high levels of nitrate and represent the largest contributor to nitrite exposure for food-producing animals. Interspecies differences in sensitivity to nitrite intoxication principally result from physiological and anatomical differences in nitrite handling. In the case of livestock both pigs and cattle are relatively susceptible. With pigs this is due to a combination of low levels of bacterial nitrite reductase and hence potential to reduce nitrite to ammonia as well as reduced capacity to detoxify MetHb back to haemoglobin (Hb) due to intrinsically low levels of MetHb reductase. In cattle the sensitivity is due to the potential for high dietary intake and high levels of rumen conversion of nitrate to nitrite, and an adaptable gut flora which at normal loadings shunts nitrite to ammonia for biosynthesis. However when this escape mechanism gets overloaded, nitrite builds up and can enter the blood stream resulting in methemoglobinemia. Looking at livestock case histories reported in the literature no-observed-effect levels of 3.3 mg/kg body weight (b.w.) per day for nitrite in pigs and cattle were estimated and related to the total daily nitrite intake that would result from complete feed at the EU maximum permissible level. This resulted in margins of safety of 9-fold and 5-fold for pigs and cattle, respectively. Recognising that the bulkiness of animal feed limits their consumption, these margins in conjunction with good agricultural practise were considered satisfactory for the protection of livestock health. A human health risk assessment was also

  19. The Reaction between Iron(II) Iodide and Potassium Dichromate(VI) in Acidified Aqueous Solution

    ERIC Educational Resources Information Center

    Talbot, Christopher

    2013-01-01

    This "Science note" teaching lesson explores the possible reaction between the ions in a reaction mixture consisting of iron(II) iodide and potassium dichromate(VI) in acidified aqueous solution. The electrode potentials will be used to deduce any spontaneous reactions under standard thermodynamic conditions (298 K, 1 bar (approximately…

  20. Quality evaluation of packaged acidified vegetables subjected to continuous microwave pasteurization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study evaluated the use of 915 MHz continuous microwave processing with a rotation apparatus for pasteurization of acidified vegetable packages. Broccoli florets, and 1.2 cm cubes of broccoli stems, red bell pepper, and sweetpotato were pre-equilibrated to 1 g/100 g NaCl and 0.38 g/100 mL citric...

  1. The chemical behavior of acidified chromium (3) solutions. B.S. Thesis

    NASA Technical Reports Server (NTRS)

    Terman, D. K.

    1981-01-01

    A unique energy-storage system has been developed at NASA's Lewis Research Center called REDOX. This NASA-REDOX system is an electrochemical storage device that utilized the oxidation and reduction of two fully soluble redox couples for charging and discharging. The redox couples now being investigated are acidified chloride solutions of chromium (Cr(+2)/Cr(+3)) and iron (Fe(+2)/Fe(+3)).

  2. Sodium Bicarbonate

    MedlinePlus

    ... to 2 hours after meals, with a full glass of water. If you are using sodium bicarbonate for another reason, it may be taken with or without food. Do not take sodium bicarbonate on an overly full stomach.Dissolve sodium bicarbonate powder in at least 4 ounces (120 milliliters) of ...

  3. Dust in an acidified ocean: iron bioavailability, phytoplankton growth and DMS

    NASA Astrophysics Data System (ADS)

    Mélançon, J.; Levasseur, M.; Lizotte, M.; Scarratt, M. G.; Tremblay, J. E.; Tortell, P. D.; Yang, G.; Shi, G. Y.; Gao, H.; Semeniuk, D.; Robert, M.; Arychuk, M.; Johnson, K.; Sutherland, N.; Davelaar, M.; Nemcek, N.; Pena, A.; Richardson, W.

    2015-12-01

    Ocean acidification (OA) is likely to have an effect on the fertilizing potential of desert dust in high-nutrient, low-chlorophyll oceanic regions, either by modifying Fe speciation and bioavailability, or by altering phytoplankton Fe requirements and acquisition. To address this issue, short incubations (4 days) of northeast subarctic Pacific waters enriched with either FeSO4 or dust, and maintained at pH 8.0 (in situ) and 7.8 were conducted in August 2010. We assessed the impact of a decrease in pH on dissolved Fe concentration, phytoplankton biomass, taxonomy and productivity, and the production of dimethylsulfide (DMS) and its algal precursor dimethylsulfoniopropionate (DMSP). Chlorophyll a (chl a) remained unchanged in the controls and doubled in both the FeSO4-enriched and dust-enriched incubations, confirming the Fe-limited status of the plankton assemblage during the experiment. In the acidified treatments, a significant reduction (by 16-38%) of the final concentration of chl a was measured compared to their non-acidified counterparts, and a 15% reduction in particulate organic carbon (POC) concentration was measured in the dust-enriched acidified treatment compared to the dust-enriched non-acidified treatment. FeSO4 and dust additions had a fertilizing effect mainly on diatoms and cyanobacteria. Lowering the pH affected mostly the haptophytes, but pelagophyte concentrations were also reduced in some acidified treatments. Acidification did not significantly alter DMSP and DMS concentrations. These results show that dust deposition events in a low-pH iron-limited Northeast subarctic Pacific are likely to stimulate phytoplankton growth to a lesser extent than in today's ocean during the few days following fertilization and point to a low initial sensitivity of the DMSP and DMS dynamics to OA.

  4. The partial characterization of purified nitrite reductase and hydroxylamine oxidase from Nitrosomonas europaea

    PubMed Central

    Ritchie, G. A. F.; Nicholas, D. J. D.

    1974-01-01

    Nitrite reductase has been separated from cell-free extracts of Nitrosomonas and partially purified from hydroxylamine oxidase by polyacrylamide-gel electrophoresis. In its oxidized state the enzyme, which did not contain haem, had an extinction maximum at 590nm, which was abolished on reduction. Sodium diethyldithiocarbamate was a potent inhibitor of nitrite reductase. Enzyme activity was stimulated 2.5-fold when remixed with hydroxylamine oxidase, but was unaffected by mammalian cytochrome c. The enzyme also exhibited a low hydroxylamine-dependent nitrite reductase activity. The results suggest that this enzyme is similar to the copper-containing `denitrifying enzyme' of Pseudomonas denitrificans. A dithionite-reduced, 465nm-absorbing haemoprotein was associated with homogeneous preparations of hydroxylamine oxidase. The band at 465nm maximum was not reduced during the oxidation of hydroxylamine although the extinction was abolished on addition of hydroxylamine, NO2− or CO. These last-named compounds when added to the oxidized enzyme precluded the appearance of the 465nm-absorption band on addition of dithionite. Several properties of 465nm-absorbing haemoprotein are described. PMID:4154745

  5. Fetal-maternal nitrite exchange in sheep: experimental data, a computational model and an estimate of placental nitrite permeability

    PubMed Central

    Schroeder, Hobe J.; Kanda, Eriko; Power, Gordon G.; Blood, Arlin B.

    2016-01-01

    Introduction Nitrite conveys NO-bioactivity that may contribute to the high-flow, low-resistance character of the fetal circulation. Fetal blood nitrite concentrations depend partly on placental permeability which has not been determined experimentally. We aimed to extract the placental permeability-surface (PS) product for nitrite in sheep from a computational model. Methods An eight-compartment computational model of the fetal-maternal unit was constructed (Matlab® (R2013b (8.2.0.701), MathWorks Inc., Natick, MA). Taking into account fetal and maternal body weights, four variables (PS, the rate of nitrite metabolism within red cells, and two nitrite distribution volumes, one with and one without nitrite metabolism), were varied to obtain optimal fits to the experimental plasma nitrite profiles observed following the infusion of nitrite into either the fetus (n=7) or the ewe (n=8). Results The model was able to replicate the average and individual nitrite-time profiles (r2 > 0.93) following both fetal and maternal nitrite infusions with reasonable variation of the four fitting parameters. Simulated transplacental nitrite fluxes were able to predict umbilical arterial-venous nitrite concentration differences that agreed with experimental values. The predicted PS values for a 3 kg sheep fetus were 0.024±0.005 l·min−1 in the fetal-maternal direction and 0.025±0.003 l·min−1 in the maternal-fetal direction (mean±SEM). These values are many-fold higher than the reported PS product for chloride anions across the sheep placenta. Conclusion The result suggests a transfer of nitrite across the sheep placenta that is not exclusively by simple diffusion through water-filled channels. PMID:26907384

  6. Growth of nitrite-oxidizing bacteria by aerobic hydrogen oxidation.

    PubMed

    Koch, Hanna; Galushko, Alexander; Albertsen, Mads; Schintlmeister, Arno; Gruber-Dorninger, Christiane; Lücker, Sebastian; Pelletier, Eric; Le Paslier, Denis; Spieck, Eva; Richter, Andreas; Nielsen, Per H; Wagner, Michael; Daims, Holger

    2014-08-29

    The bacterial oxidation of nitrite to nitrate is a key process of the biogeochemical nitrogen cycle. Nitrite-oxidizing bacteria are considered a highly specialized functional group, which depends on the supply of nitrite from other microorganisms and whose distribution strictly correlates with nitrification in the environment and in wastewater treatment plants. On the basis of genomics, physiological experiments, and single-cell analyses, we show that Nitrospira moscoviensis, which represents a widely distributed lineage of nitrite-oxidizing bacteria, has the genetic inventory to utilize hydrogen (H2) as an alternative energy source for aerobic respiration and grows on H2 without nitrite. CO2 fixation occurred with H2 as the sole electron donor. Our results demonstrate a chemolithoautotrophic lifestyle of nitrite-oxidizing bacteria outside the nitrogen cycle, suggesting greater ecological flexibility than previously assumed.

  7. Effect of bromide and nitrite on the degradation of monochloramine

    SciTech Connect

    Valentine, R.L.; Selleck, R.E.

    1981-10-01

    The results indicate that relatively small concentrations of nitrite can greatly accelerate the degradation of monochloramine in the presence of bromide. It does not appear that nitrite is being significantly consumed in a 1:1 stoichiometric oxidation by monochloramine. If the effect of nitrite is catalytic then these results suggest that the presence of nitrite may also accelerate other oxidation-reduction reactions. For example, nitrite may play an important role in oxidant decay in partially nitrified sewage effluents where both monochloramine and nitrite may be present. If not a complex oxidation-reduction possibly involving bromide as a catalyst is indicated. The results also suggest that the presence of other potentially oxidizable species may affect oxidant decay in a manner not attributable to a simple parallel oxidation.

  8. Simultaneous ultraviolet spectrophotometric determination of nitrate and nitrite in water

    SciTech Connect

    Dong Huiru; Zhang Qing ); Jiang Meiyu )

    1991-02-01

    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.

  9. [Myocardial electrogenesis in laboratory rats under conditions of acute nitrite intoxication].

    PubMed

    Shumilova, T E; Shereshkov, V I; Ianvareva, I N; Nozdrachev, A D

    2010-01-01

    In anesthetized male rats the arterial blood pressure in femoral artery and electrocardiogram in standard leads were recorded uninterruptedly for 1-1.5 h under conditions of acute nitrite intoxication produced by a subcutaneous injection of water solution of sodium nitrite (donor of nitric oxide) at concentrations of 10, 30, and 50 mg/kg body mass. Results of the study have shown dose-dependent changes of arterial pressure as well as of time and amplitude characteristics of electrocardiogram under effect of NaNO2. At the threshold hypoxic dose, an increase of amplitude of R and S waves was observed by the 30-45th min, while at the maximal NaNO2 dose, amplitude of all waves rose by the 15th min of intoxication. High nitric doses often caused an increase of the ST segment above the isoelectric line and a rise of the amplitude of the T wave, on which a notch appeared in some cases. The change of the ECG time parameters was expressed in the dose-dependent development of bradycardia for the first 4-7 min; its level correlated with the progressively decreasing arterial pressure in the beginning (the 2-4th min) of nitrite intoxication. Variation analysis of heart rate spectral characteristics by Baevskii has revealed a rise of the total spectral power of pulse oscillations. Under effect of nitrite, in the spectrum of cardiointervals, quent recovery of the normal ECG spectrum in the end of the experimental period. The maximal nitrite dose produced more pronounced shifts of the heart rate spectrum towards the LF and VLF diapasons that were not restored for 1 h of experiment. Transitory processes of readjustment of the cardiac rhythm had discrete character. The nitrite dose of 50 mg/kg body mass increased the RR-interval after 4-7 min with amplitude steps of 3-5 imp/s and the time constant of 20-40 s. The revealed ECG changes had the reflex (enhancement of parasympathetic tonus) and metabolic (the hypoxic and histotoxic damage of myocardium) nature.

  10. The effect of sodium chloride on the two-step kinetics of the nitrifying process.

    PubMed

    Sánchez, Omar; Aspé, Estrella; Martí, María C; Roeckel, Marlene

    2004-01-01

    Sodium chloride affects the transformation rate of several compounds in bioreactors. Most authors report a decrease in microorganism activity at increasing salt concentrations. In this work, a kinetic model that relates sodium chloride concentration with the rates of each step of the nitrification process is proposed; thus, the effect of sodium chloride concentration (0 to 60 g/L) on the nitritation and nitratation rates was separately studied. To carry out the independent study of each step, a combination of the respirometric method with sodium azide, an inhibitor of the nitratation step, was performed. The dot-blot hybridization technique with 16S rRNA-targeted probes was used to determine the ammonia-oxidizing and nitrite-oxidizing bacterial fraction, then it was possible to relate the culture's function with its biological composition. Rates of both steps were linearly reduced at increasing salt concentrations: the nitratation rate was more affected than the nitritation rate. Simulations carried out in a nitrifying sequencing batch reactor indicate that nitrite might accumulate at high salt concentrations. Sodium chloride exerts a reversible inhibition on ammonia oxidation and nitrite oxidation.

  11. Effect of Sweet Orange Fruit Waste Diets and Acidifier on Haematology and Serum Chemistry of Weanling Rabbits

    PubMed Central

    Daudu, Oluremi Martha; Sani, Rahamatu Usman; Adedibu, Iyetunde Ifeyori; Ademu, Lawrence Anebi; Bawa, Gideon Shaibu; Olugbemi, Taiye Sunday

    2014-01-01

    A total of thirty-five mixed breed (35) rabbits of average weight of 700 g aged 5-6 weeks were allocated to seven treatments in a completely randomised design to investigate the effect of sweet orange fruit waste (SOFW) and acidomix acidifier on haematology and serum chemistry. The diets were 0% SOFW, 10% SOFW with 0.5% acidomix, 10% SOFW with 0.7 acidomix, 15% SOFW with 0.5% acidifier, 15% SOFW with 0.7% acidifier, 20% SOFW with 0.5% acidifier, and 20% SOFW with 0.7% acidifier. Blood samples were analyzed for haemoglobin (hb) concentration, white blood cells (WBC), red blood cells (RBC), differential WBC count (lymphocyte, basophil, eosinophil, monocyte, and neutrophil), alanine amino transferase (ALT), alkaline phosphatase (ALP), aspartate amino transferase (AST), total protein, albumin, and globulin. There was no interaction between SOFW and acidifier for the haematological and most of the serum chemistry parameters but significant difference was observed in ALT; however the values were within the normal range. SOFW had no significant effect on all haematological and serum chemistry parameters. Acidomix had significant effect (P < 0.05) on haemoglobin concentration; rabbits fed 0.5% acidomix diets had higher values which were within the normal range. It is therefore concluded that SOFW with acidifier up to 20% had no detrimental effect on serum chemistry and haematology. PMID:26464931

  12. Nitrite therapy is neuroprotective and safe in cardiac arrest survivors.

    PubMed

    Dezfulian, Cameron; Alekseyenko, Aleksey; Dave, Kunjan R; Raval, Ami P; Do, Rose; Kim, Francis; Perez-Pinzon, Miguel A

    2012-05-15

    Cardiac arrest results in significant mortality after initial resuscitation due in most cases to ischemia-reperfusion induced brain injury and to a lesser degree myocardial dysfunction. Nitrite has previously been shown to protect against reperfusion injury in animal models of focal cerebral and heart ischemia. Nitrite therapy after murine cardiac arrest improved 22 h survival through improvements in myocardial contractility. These improvements accompanied transient mitochondrial inhibition which reduced oxidative injury to the heart. Based on preliminary evidence that nitrite may also protect against ischemic brain injury, we sought to test this hypothesis in a rat model of asphyxia cardiac arrest with prolonged survival (7d). Cardiac arrest resulted in hippocampal CA1 delayed neuronal death well characterized in this and other cardiac arrest models. Nitrite therapy did not alter post-arrest hemodynamics but did result in significant (75%) increases in CA1 neuron survival. This was associated with increases in hippocampal nitrite and S-nitrosothiol levels but not cGMP shortly after therapy. Mitochondrial function 1h after resuscitation trended towards improvement with nitrite therapy. Based on promising preclinical data, the first ever phase I trial of nitrite infusions in human cardiac arrest survivors has been undertaken. We present preliminary data showing low dose nitrite infusion did not result in hypotension or cause methemoglobinemia. Nitrite thus appears safe and effective for clinical translation as a promising therapy against cardiac arrest mediated heart and brain injury.

  13. Inter- and intra-specific variation on sensitivity of larval amphibians to nitrite.

    PubMed

    Shinn, C; Marco, A; Serrano, L

    2008-03-01

    Several authors have suggested that nitrogen-based fertilizers may be contributing to the global amphibian decline. We have studied the impact of sodium nitrite on early aquatic stages of Epidalea calamita, Pelophylax perezi and Hyla meridionalis larvae from Doñana National Park (coastal wetland) and P. perezi from Gredos Mountain (high mountain ponds), exposed during 10 to 16 days. After 8 days of exposure all P. perezi larvae from Doñana presented 100% mortality at 5 mg l(-1)N-NO2(-) while E. calamita larvae mortality rates were significantly lower at that concentration after 15 days. However, for H. meridionalis at day 15 no deaths were registered at 5 mg l(-1)N-NO2(-) and at 20 mg l(-1)N-NO2(-) presented intermediate mortality rates. In Doñana the 10 d LC50 of older H. meridionalis larvae was between 20 and 30 mg l(-1)N-NO2(-) whilst for P. perezi it was below 5 mg l(-1)N-NO2(-). These results indicate inter-specific variation of the sensitivity of larval amphibians to nitrite. Gredos Mountain P. perezi larvae exposed since the egg stage were highly sensitive to nitrite, with a 16 d LC50 below 0.5 mg l(-1)N-NO2(-). The same species in Doñana had a 15 d LC50 between 5 and mg l(-1)N-NO2(-). These results suggest that there is also intra-specific variation in sensitivity of amphibian larvae to nitrite: mountain amphibian populations appear to be more sensitive to polluted environments than coastal populations. Geographic and genetic variation and evolutionary adaptation of tolerance may also be the keys to variation amongst populations of the same species.

  14. Differences in nitrite-oxidizing communities and kinetics in a brackish environment after enrichment at low and high nitrite concentrations.

    PubMed

    Tangkitjawisut, Wipasanee; Limpiyakorn, Tawan; Powtongsook, Sorawit; Pornkulwat, Preeyaporn; Suwannasilp, Benjaporn Boonchayaanant

    2016-04-01

    Nitrite accumulation in shrimp ponds can pose serious adverse effects to shrimp production and the environment. This study aims to develop an effective process for the enrichment of ready-to-use nitrite-oxidizing bacteria (NOB) inocula that would be appropriate for nitrite removal in brackish shrimp ponds. To achieve this objective, the effects of nitrite concentrations on NOB communities and nitrite oxidation kinetics in a brackish environment were investigated. Moving-bed biofilm sequencing batch reactors and continuous moving-bed biofilm reactors were used for the enrichment of NOB at various nitrite concentrations, using sediment from brackish shrimp ponds as seed inoculum. The results from NOB population analysis with quantitative polymerase chain reaction (qPCR) show that only Nitrospira were detected in the sediment from the shrimp ponds. After the enrichment, both Nitrospira and Nitrobacter coexisted in the reactors controlling effluent nitrite at 0.1 and 0.5 mg-NO2(-)-N/L. On the other hand, in the reactors controlling effluent nitrite at 3, 20, and 100 mg-NO2(-)-N/L, Nitrobacter outcompeted Nitrospira in many orders of magnitude. The half saturation coefficients (Ks) for nitrite oxidation of the enrichments at low nitrite concentrations (0.1 and 0.5 mg-NO2(-)-N/L) were in the range of 0.71-0.98 mg-NO2(-)-N/L. In contrast, the K(s) values of NOB enriched at high nitrite concentrations (3, 20, and 100 mg-NO2(-)-N/L) were much higher (8.36-12.20 mg-NO2(-)-N/L). The results suggest that the selection of nitrite concentrations for the enrichment of NOB inocula can significantly influence NOB populations and kinetics, which could affect the effectiveness of their applications in brackish shrimp ponds.

  15. Independence of nitrate and nitrite inhibition of Desulfovibrio vulgaris Hildenborough and use of nitrite as a substrate for growth.

    PubMed

    Korte, Hannah L; Saini, Avneesh; Trotter, Valentine V; Butland, Gareth P; Arkin, Adam P; Wall, Judy D

    2015-01-20

    Sulfate-reducing microbes, such as Desulfovibrio vulgaris Hildenborough, cause “souring” of petroleum reservoirs through produced sulfide and precipitate heavy metals, either as sulfides or by alteration of the metal reduction state. Thus, inhibitors of these microbes, including nitrate and nitrite ions, are studied in order to limit their impact. Nitrite is a potent inhibitor of sulfate reducers, and it has been suggested that nitrate does not inhibit these microbes directly but by reduction to nitrite, which serves as the ultimate inhibitor. Here we provide evidence that nitrate inhibition of D. vulgaris can be independent of nitrite production. We also show that D. vulgaris can use nitrite as a nitrogen source or terminal electron acceptor for growth. Moreover, we report that use of nitrite as a terminal electron acceptor requires nitrite reductase (nrfA) as a D. vulgaris nrfA mutant cannot respire nitrite but remains capable of utilizing nitrite as a nitrogen source. These results illuminate previously uncharacterized metabolic abilities of D. vulgaris that may allow niche expansion in low-sulfate environments. Understanding these abilities may lead to better control of sulfate-reducing bacteria in industrial settings and more accurate prediction of their interactions in the environment.

  16. Taxis response of various denitrifying bacteria to nitrate and nitrite.

    PubMed

    Lee, Dong Yun; Ramos, Adela; Macomber, Lee; Shapleigh, James P

    2002-05-01

    The taxis response of Rhodobacter sphaeroides 2.4.1 and 2.4.3, Rhodopseudomonas palustris, and Agrobacterium tumefaciens to nitrate and nitrite was evaluated by observing the macroscopic behavior of cells suspended in soft agar and incubated under various conditions. R. sphaeroides 2.4.3, which is capable of both nitrate and nitrite reduction, showed a taxis response to both nitrate and nitrite. R. sphaeroides 2.4.1, which contains nitrate reductase but not nitrite reductase, did not show a taxis response towards either nitrogen oxide. Insertional inactivation of the nitrite reductase structural gene or its transcriptional regulator, NnrR, in strain 2.4.3 caused a loss of a taxis response towards both nitrate and nitrite. An isolate of 2.4.1 carrying a copy of the nitrite reductase gene from 2.4.3 showed a taxis response to both nitrogen oxides. The taxis response of 2.4.3 was observed under anaerobic conditions, suggesting that the taxis response was due to nitrate and nitrite respiration, not to inhibition of oxygen respiration by respiration of nitrogen oxides. Strain 2.4.3 showed a taxis response to nitrate and nitrite under photosynthetic and aerobic conditions. Changing the carbon source in the culture medium caused an unexpected subtle shift in the taxis response of 2.4.3 to nitrite. A taxis response to nitrogen oxides was also observed in R. palustris and A. tumefaciens. R. palustris exhibited a taxis response to nitrite but not to nitrate, while A. tumefaciens exhibited a response to both compounds.

  17. Taxis Response of Various Denitrifying Bacteria to Nitrate and Nitrite

    PubMed Central

    Lee, Dong Yun; Ramos, Adela; Macomber, Lee; Shapleigh, James P.

    2002-01-01

    The taxis response of Rhodobacter sphaeroides 2.4.1 and 2.4.3, Rhodopseudomonas palustris, and Agrobacterium tumefaciens to nitrate and nitrite was evaluated by observing the macroscopic behavior of cells suspended in soft agar and incubated under various conditions. R. sphaeroides 2.4.3, which is capable of both nitrate and nitrite reduction, showed a taxis response to both nitrate and nitrite. R. sphaeroides 2.4.1, which contains nitrate reductase but not nitrite reductase, did not show a taxis response towards either nitrogen oxide. Insertional inactivation of the nitrite reductase structural gene or its transcriptional regulator, NnrR, in strain 2.4.3 caused a loss of a taxis response towards both nitrate and nitrite. An isolate of 2.4.1 carrying a copy of the nitrite reductase gene from 2.4.3 showed a taxis response to both nitrogen oxides. The taxis response of 2.4.3 was observed under anaerobic conditions, suggesting that the taxis response was due to nitrate and nitrite respiration, not to inhibition of oxygen respiration by respiration of nitrogen oxides. Strain 2.4.3 showed a taxis response to nitrate and nitrite under photosynthetic and aerobic conditions. Changing the carbon source in the culture medium caused an unexpected subtle shift in the taxis response of 2.4.3 to nitrite. A taxis response to nitrogen oxides was also observed in R. palustris and A. tumefaciens. R. palustris exhibited a taxis response to nitrite but not to nitrate, while A. tumefaciens exhibited a response to both compounds. PMID:11976082

  18. Sodium in diet

    MedlinePlus

    Diet - sodium (salt); Hyponatremia - sodium in diet; Hypernatremia - sodium in diet; Heart failure - sodium in diet ... The body uses sodium to control blood pressure and blood volume. Your body also needs sodium for your muscles and nerves to work ...

  19. Nitrite Reduces Cytoplasmic Acidosis under Anoxia1

    PubMed Central

    Libourel, I.G.L.; van Bodegom, P.M.; Fricker, M.D.; Ratcliffe, R.G.

    2006-01-01

    The ameliorating effect of nitrate on the acidification of the cytoplasm during short-term anoxia was investigated in maize (Zea mays) root segments. Seedlings were grown in the presence or absence of nitrate, and changes in the cytoplasmic and vacuolar pH in response to the imposition of anoxia were measured by in vivo 31P nuclear magnetic resonance spectroscopy. Soluble ions and metabolites released to the suspending medium by the anoxic root segments were measured by high-performance liquid chromatography and 1H nuclear magnetic resonance spectroscopy, and volatile metabolites were measured by gas chromatography and gas chromatography-mass spectrometry. The beneficial effect of nitrate on cytoplasmic pH regulation under anoxia occurred despite limited metabolism of nitrate under anoxia, and modest effects on the ions and metabolites, including fermentation end products, released from the anoxic root segments. Interestingly, exposing roots grown and treated in the absence of nitrate to micromolar levels of nitrite during anoxia had a beneficial effect on the cytoplasmic pH that was comparable to the effect observed for roots grown and treated in the presence of nitrate. It is argued that nitrate itself is not directly responsible for improved pH regulation under anoxia, contrary to the usual assumption, and that nitrite rather than nitrate should be the focus for further work on the beneficial effect of nitrate on flooding tolerance. PMID:17071644

  20. Remediation of Cr(VI)-Contaminated Soil Using the Acidified Hydrazine Hydrate.

    PubMed

    Ma, Yameng; Li, Fangfang; Jiang, Yuling; Yang, Weihua; Lv, Lv; Xue, Haotian; Wang, Yangyang

    2016-09-01

    Acidified hydrazine hydrate was used to remediate Cr(VI)-contaminated soil. The content of water-soluble Cr(VI) in contaminated soil was 4977.53 mg/kg. The optimal initial pH of hydrazine hydrate solution, soil to solution ratio and molar ratio of Cr(VI) to hydrazine hydrate for remediation of Cr(VI)-contaminated soil were 5.0, 3:1 and 1:3, respectively. Over 99.50 % of water-soluble Cr(VI) in the contaminated soil was reduced at the optimal condition within 30 min. The remediated soil can keep stable within 4 months. Meanwhile the total phosphorus increased from 0.47 to 4.29 g/kg, indicating that using of acidified hydrazine hydrate is an effective method to remediate Cr(VI)-contaminated soil.

  1. Determination of 5-log pathogen reduction times for heat-processed, acidified vegetable brines.

    PubMed

    Breidt, F; Hayes, J S; Osborne, J A; McFeeters, R F

    2005-02-01

    Recent outbreaks of acid-resistant food pathogens in acid foods, including apple cider and orange juice, have raised concerns about the safety of acidified vegetable products. We determined pasteurization times and temperatures needed to assure a 5-log reduction in the numbers of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella strains in acidified cucumber pickle brines. Cocktails of five strains of each pathogen were (separately) used for heat-inactivation studies between 50 and 60 degrees C in brines that had an equilibrated pH value of 4.1. Salmonella strains were found to be less heat resistant than E. coli O157:H7 or L. monocytogenes strains. The nonlinear killing curves generated during these studies were modeled using a Weibull function. We found no significant difference in the heat-killing data for E. coli O157:H7 and L. monocytogenes (P = 0.9709). The predicted 5-log reduction times for E. coli O157:H7 and L. monocytogenes were found to fit an exponential decay function. These data were used to estimate minimum pasteurization times and temperatures needed to ensure safe processing of acidified pickle products and show that current industry pasteurization practices offer a significant margin of safety.

  2. Relative acidifying activity of anionic salts commonly used to prevent milk fever.

    PubMed

    Goff, J P; Ruiz, R; Horst, R L

    2004-05-01

    High cation diets can cause milk fever in dairy cows as they induce a metabolic alkalosis reducing the ability of the cow to maintain calcium homeostasis at the onset of lactation. Adding anions to the diet can offset the effect of the high cation forages by inducing a mild metabolic acidosis, restoring the ability to maintain calcium homeostasis. The difference in mEq of dietary cations and anions (DCAD) is most often expressed as (Na(+) + K+) - (Cl- + S(--)). This equation implies that a mEq of chloride and a mEq of sulfate are equipotent in their ability to alter acid-base balance of the cow. Using blood and urine pH to monitor effects on acid-base balance, experiments were conducted to test the relative acidifying activity of various sulfate and chloride anion sources in nonpregnant, nonlactating Jersey cows. Across all experiments, chloride proved to have about 1.6 times the acidifying activity of sulfate. Calcium and magnesium, ignored by the common DCAD equation, had a small but significant alkalinizing effect when accompanying chloride or sulfate. The ranking of the anion sources tested at a dose of 2 Eq/d, from most to least potent urine acidifier, was hydrochloric acid, ammonium chloride, calcium chloride, calcium sulfate, magnesium sulfate, and sulfur. These data should allow more accurate prediction of the response of late gestation cows to dietary cation-anion manipulation.

  3. Amperometric Carbon Fiber Nitrite Microsensor for In Situ Biofilm Monitoring

    EPA Science Inventory

    A highly selective needle type solid state amperometric nitrite microsensor based on direct nitrite oxidation on carbon fiber was developed using a simplified fabrication method. The microsensor’s tip diameter was approximately 7 µm, providing a high spatial resolution of at lea...

  4. The Interaction of Nitrites with Food, Drugs, and Contaminants.

    ERIC Educational Resources Information Center

    Greenland, Sander

    1978-01-01

    Nitrites commonly occur in food and drinking water as additives, contaminants, or products of biological processes. These highly reactive substances combine with other commonly ingested substances to form potent carcinogens. Controls are needed on levels of nitrites and reactive contaminants in food and drinking water. (RE)

  5. Cardiac contractility in Antarctic teleost is modulated by nitrite through xanthine oxidase and cytochrome p-450 nitrite reductase.

    PubMed

    Garofalo, Filippo; Amelio, Daniela; Gattuso, Alfonsina; Cerra, Maria Carmela; Pellegrino, Daniela

    2015-09-15

    In mammalian and non-mammalian vertebrates, nitrite anion, the largest pool of intravascular and tissue nitric oxide storage, represents a key player of many biological processes, including cardiac modulation. As shown by our studies on Antarctic teleosts, nitrite-dependent cardiac regulation is of great relevance also in cold-blooded vertebrates. This study analysed the influence elicited by nitrite on the performance of the perfused beating heart of two Antarctic stenotherm teleosts, the haemoglobinless Chionodraco hamatus (icefish) and the red-blooded Trematomus bernacchii. Since haemoglobin is crucial in nitric oxide homeostasis, the icefish, a naturally occurring genetic knockout for this protein, provides exclusive opportunities to investigate nitric oxide/nitrite signaling. In vivo, nitrite conversion to nitric oxide requires the nitrite reductase activity of xanthine oxidase and cytochrome P-450, thus the involvement of these enzymes was also evaluated. We showed that, in C. hamatus and T. bernacchii, nitrite influenced cardiac performance by inducing a concentration-dependent positive inotropic effect which was unaffected by nitric oxide scavenging by PTIO in C. hamatus, while it was abolished in T. bernacchii. Specific inhibition of xanthine oxidase and cytochrome P-450 revealed, in the two teleosts, that the nitrite-dependent inotropism required the nitrite reductase activity of both enzymes. We also found that xanthine oxidase is more expressed in C. hamatus than in T. bernacchii, while the opposite was observed concerning cytochrome P-450. Results suggested that in the heart of C. hamatus and T. bernacchii, nitrite is an integral physiological source of nitric oxide with important signaling properties, which require the nitrite reductase activity of xanthine oxidase and cytochrome P-450.

  6. Nitrite isotopes as tracers of marine N cycle processes

    NASA Astrophysics Data System (ADS)

    Casciotti, Karen L.

    2016-11-01

    Nitrite (NO2-) is a key intermediate in the marine nitrogen (N) cycle. It is produced and consumed throughout the ocean by the dominant processes driving the distribution, availability and speciation of N. However, the accumulation of nitrite is typically confined to depths near the base of the sunlit euphotic zone and in oxygen-deficient zones. These features are known as the primary and secondary nitrite maximum (PNM and SNM), respectively. The processes controlling nitrite accumulation in these features are not fully understood, but are thought to depend on the microbial community composition and its response to environmental conditions. A variety of approaches have been applied to understanding these features since their discovery, with the stable N and oxygen (O) isotope measurements of nitrite being added to this toolkit most recently. Large variations in nitrite N isotope ratios (15N/14N) and dramatic depletions in 15N contrast with more consistent nitrite O isotope ratios (18O/16O) in the SNM. These signals provide unique information about the mechanisms of nitrite consumption in the SNM. By contrast, nitrite in the PNM shows less variation in 15N/14N, but variations in 18O/16O that provide insight into the mechanisms and rates of N cycling there. This review presents a synthesis of nitrite isotope measurements in the marine environment, highlighting the insights that have been gained from these measurements. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  7. Purification and characterization of assimilatory nitrite reductase from Candida utilis.

    PubMed

    Sengupta, S; Shaila, M S; Rao, G R

    1996-07-01

    Nitrate assimilation in many plants, algae, yeasts and bacteria is mediated by two enzymes, nitrate reductase (EC 1.6.6.2) and nitrite reductase (EC 1.7.7.1). They catalyse the stepwise reduction of nitrate to nitrite and nitrite to ammonia respectively. The nitrite reductase from an industrially important yeast, Candida utilis, has been purified to homogeneity. Purified nitrite reductase is a heterodimer and the molecular masses of the two subunits are 58 and 66 kDa. The native enzyme exhibits a molecular mass of 126 kDa as analysed by gel filtration. The identify of the two subunits of nitrite reductase was confirmed by immunoblotting using antibody for Cucurbita pepo leaf nitrite reductase. The presence of two different sized transcripts coding for the two subunits was confirmed by (a) in vitro translation of mRNA from nitrate-induced C. utilis followed by immunoprecipitation of the in vitro translated products with heterologous nitrite reductase antibody and (b) Northern-blot analysis. The 66 kDa subunit is acidic in nature which is probably due to its phosphorylated status. The enzyme is stable over a range of temperatures. Both subunits can catalyse nitrite reduction, and the reconstituted enzyme, at a higher protein concentration, shows an activity similar to that of the purified enzyme. Each of these subunits has been shown to contain a few unique peptides in addition to a large number of common peptides. Reduced Methyl Viologen has been found to be as effective an electron donor as NADPH in the catalytic process, a phenomenon not commonly seen for nitrite reductases from other systems.

  8. EPR spectroscopy of nitrite complexes of methemoglobin.

    PubMed

    Schwab, David E; Stamler, Jonathan S; Singel, David J

    2010-07-19

    The chemical interplay of nitrogen oxides (NO's) with hemoglobin (Hb) has attracted considerable recent attention because of its potential significance in the mechanism of NO-related vasoactivity regulated by Hb. An important theme of this interplay-redox coupling in adducts of heme iron and NO's-has sparked renewed interest in fundamental studies of FeNO(x) coordination complexes. In this Article, we report combined UV-vis and comprehensive electron paramagnetic resonance (EPR) spectroscopic studies that address intriguing questions raised in recent studies of the structure and affinity of the nitrite ligand in complexes with Fe(III) in methemoglobin (metHb). EPR spectra of metHb/NO(2)(-) are found to exhibit a characteristic doubling in their sharper spectral features. Comparative EPR measurements at X- and S-band frequencies, and in D(2)O versus H(2)O, argue against the assignment of this splitting as hyperfine structure. Correlated changes in the EPR spectra with pH enable complete assignment of the spectrum as deriving from the overlap of two low-spin species with g values of 3.018, 2.122, 1.45 and 2.870, 2.304, 1.45 (values for samples at 20 K and pH 7.4 in phosphate-buffered saline). These g values are typical of g values found for other heme proteins with N-coordinated ligands in the binding pocket and are thus suggestive of N-nitro versus O-nitrito coordination. The positions and shapes of the spectral lines vary only slightly with temperature until motional averaging ensues at approximately 150 K. The pattern of motional averaging in the variable-temperature EPR spectra and EPR studies of Fe(III)NO(2)(-)/Fe(II)NO hybrids suggest that one of two species is present in both of the alpha and beta subunits, while the other is exclusive to the beta subunit. Our results also reconfirm that the affinity of nitrite for metHb is of millimolar magnitude, thereby making a direct role for nitrite in physiological hypoxic vasodilation difficult to justify.

  9. Sources and sinks for ammonia and nitrite on the early Earth and the reaction of nitrite with ammonia

    NASA Technical Reports Server (NTRS)

    Summers, D. P.

    1999-01-01

    An analysis of sources and sinks for ammonia and nitrite on the early Earth was conducted. Rates of formation and destruction, and steady state concentrations of both species were determined by steady state kinetics. The importance of the reaction of nitrite with ammonia on the feasibility of ammonia formation from nitrite was evaluated. The analysis considered conditions such as temperature, ferrous iron concentration, and pH. For sinks we considered the reduction of nitrite to ammonia, reaction between nitrite and ammonia, photochemical destruction of both species, and destruction at hydrothermal vents. Under most environmental conditions, the primary sink for nitrite is reduction to ammonia. The reaction between ammonia and nitrite is not an important sink for either nitrite or ammonia. Destruction at hydrothermal vents is important at acidic pH's and at low ferrous iron concentrations. Photochemical destruction, even in a worst case scenario, is unimportant under many conditions except possibly under acidic, low iron concentration, or low temperature conditions. The primary sink for ammonia is photochemical destruction in the atmosphere. Under acidic conditions, more of the ammonia is tied up as ammonium (reducing its vapor pressure and keeping it in solution) and hydrothermal destruction becomes more important.

  10. Sodium MRI.

    PubMed

    Ouwerkerk, Ronald

    2011-01-01

    Sodium ((23)Na) imaging has a place somewhere between (1)H-MRI and MR spectroscopy (MRS). Like MRS it potentially provides information on metabolic processes, but only one single resonance of ionic (23)Na is observed. Therefore pulse sequences do not need to code for a chemical shift dimension, allowing (23)Na images to be obtained at high resolutions as compared to MRS. In this chapter the biological significance of sodium in the brain will be discussed, as well as methods for observing it with (23)Na-MRI. Many vital cellular processes and interactions in excitable tissues depend on the maintenance of a low intracellular and high extracellular sodium concentration. Healthy cells maintain this concentration gradient at the cost of energy. Leaky cell membranes or an impaired energy metabolism immediately leads to an increase in cytosolic total tissue sodium. This makes sodium a biomarker for ischemia, cancer, excessive tissue activation, or tissue damage as might be caused by ablation therapy. Special techniques allow quantification of tissue sodium for the monitoring of disease or therapy in longitudinal studies or preferential observation of the intracellular component of the tissue sodium. New methods and high-field magnet technology provide new opportunities for (23)Na-MRI in clinical and biomedical research.

  11. Dalteparin sodium.

    PubMed

    Pineo, G F; Hull, R D

    2001-08-01

    Dalteparin sodium (Fragmin, Pharmacia Corporation) is a low molecular weight heparin (LMWH) with a mean molecular weight of approximately 5000 Da. As with the other LMWHs, dalteparin sodium has certain advantages over unfractionated heparin (UFH), most important of which are improved bio-availability by sc. injection, a prolonged antithrombotic activity which is highly correlated with body weight permitting the o.d. administration of the drug. Dalteparin sodium has been subjected to a large number of well-designed randomised clinical trials for the prevention and treatment of thrombotic disorders. Based on data from the randomised clinical trials, dalteparin sodium has been approved internationally for a wide spectrum of clinical indications (e.g., prevention of thromboembolic events after surgery). Dalteparin sodium has also been studied in randomised controlled trials in the maintenance of graft patentcy following peripheral vascular surgery, in place of warfarin for the long-term treatment of patients presenting with deep vein thrombosis (DVT), in the prevention of upper extremity thrombosis in patients with indwelling portacath devices and in pregnant patients with a history of previous venous thromboembolism with or without thrombophilia. Dalteparin sodium has been compared with heparin for the prevention of thrombotic complications during haemodyalisis and haemofiltration. These studies have shown promising results but further work is required before dalteparin sodium can be recommended for these indications.

  12. [Modifying effect of nitrites on pulmonary blastogenesis and viral leukogenesis in mice: role of nitric oxide and dioxide].

    PubMed

    Il'nitskiĭ, A P; Reutov, V P; Ryzhova, N I; Kolpakova, A S; Deriagina, V P; Nekrasova, E A; Savluchinskaia, L A; Travkin, A G

    2000-01-01

    The long-term effects of sodium nitrite (NaNO2) on carcinogenesis induced by urethane (total dose 1.0 mg/g body weight) in low-grade cancer F1 (C57BLxCBA) and high-grade A/Snell mice and on viral (Rausher leukemia virus) leukomogenesis in Balb/c mice. The murine intake of NaNO2 with water (50 mg/l) causes a statistically significant increase in the number of adenomas in the lung. Examining the mechanism of conversion of NO2- to NO led to the assumption that the free radical compounds NO and NO2 are involved in the potentiating action of NO2 on blastomogenesis. The use of the oxidant emoxypine (3-hydroxypyridine) confirmed the above. The role of NO and NO2 in the intracellular processes under the modifying effects of nitrites and nitrates on blastomogenesis is analyzed.

  13. Dietary nitrite reverses features of postmenopausal metabolic syndrome induced by high fat diet and ovariectomy in mice.

    PubMed

    Ohtake, Kazuo; Ehara, Nobuyuki; Chiba, Hiroshige; Nakano, Genya; Sonoda, Kunihiro; Ito, Junta; Uchida, Hiroyuki; Kobayashi, Jun

    2017-02-14

    Menopausal women are at greater risk of developing metabolic syndrome with reduced endothelial nitric oxide synthase (eNOS) activity. Hormone replacement therapy increases eNOS activity and normalizes some characteristics of metabolic syndrome. We hypothesized that nitric oxide (NO) supplementation should have a therapeutic effect in this syndrome. We examined the effect of dietary nitrite on mice model with postmenopausal metabolic syndrome induced by ovariectomy (OVX) with high fat diet (HF). C57BL/6 female mice were divided into five groups, sham+normal fat diet (NF), sham+ HF, OVX+HF without or with sodium nitrite (50mg and 150mg/L) in drinking water. Daily food intake and weekly body weight were monitored for 18 weeks. OVX and HF significantly reduced plasma levels of nitrate/nitrite (NOx), and developed obesity with visceral hypertrophic adipocytes, and increased transcriptional levels of monocyte chemoattractant protein-1 (MCP-1), tumor necrotizing factor-α (TNF-α) and interleukin-6 (IL-6) in visceral fat tissues. The proinflammatory state in the adipocytes provoked severe hepatosteatosis and insulin resistance in OVX+HF group compared with sham+NF group. However, dietary nitrite significantly suppressed adipocyte hypertrophy and transcriptions of proinflammatory cytokines in visceral fat in a dose dependent manner. The improvement of visceral inflammatory state consequently reversed the hepatosteatosis and insulin resistance observed in OVX+HF mice. These results suggest that endogenous NO defect might underlie postmenopausal metabolic syndrome, and dietary nitrite provides an alternative source of NO, and subsequently compensating for metabolic impairments of this syndrome.

  14. SIRT3-AMPK Activation by Nitrite and Metformin Improves Hyperglycemia and Normalizes Pulmonary Hypertension Associated with Heart Failure with Preserved Ejection Fraction (PH-HFpEF)

    PubMed Central

    Lai, Yen-Chun; Tabima, Diana M.; Dube, John J.; Hughan, Kara S.; Vanderpool, Rebecca R.; Goncharov, Dmitry A.; St Croix, Claudette M.; Garcia-Ocaña, Adolfo; Goncharova, Elena A.; Tofovic, Stevan P.; Mora, Ana L.; Gladwin, Mark T.

    2016-01-01

    Background Pulmonary hypertension associated with heart failure with preserved ejection fraction (PH-HFpEF) is an increasingly recognized clinical complication of metabolic syndrome. No adequate animal model of PH-HFpEF is available and no effective therapies have been identified to date. A recent study suggested that dietary nitrate improves insulin resistance in eNOS null mice, and multiple studies have reported that both nitrate and its active metabolite, nitrite, have therapeutic activity in pre-clinical models of PH. Methods and Results In order to evaluate the efficacy and mechanism of nitrite in metabolic syndrome associated with PH-HFpEF, we developed a “two-hit” PH-HFpEF model in rats with multiple features of metabolic syndrome due to double leptin receptor defect (obese ZSF1) with the combined treatment of VEGF receptor blocker SU5416. Chronic oral nitrite treatment improved hyperglycemia in obese ZSF1 rats by a process that requires skeletal muscle SIRT3-AMPK-GLUT4 signaling. The glucose lowering effect of nitrite was abolished in SIRT3 deficient human skeletal muscle cells, as well as in SIRT3 knockout mice fed a high-fat diet. Skeletal muscle biopsies from humans with metabolic syndrome after 12 weeks of oral sodium nitrite and nitrate treatment (IND#115926) displayed increased activation of SIRT3 and AMPK. Finally, early treatments with nitrite and metformin at the time of SU5416 injection reduced pulmonary pressures and vascular remodeling in the PH-HFpEF model with robust activation of skeletal muscle SIRT3 and AMPK. Conclusions These studies validate a rodent model of metabolic syndrome and PH-HFpEF, suggesting a potential role of nitrite and metformin as a preventative treatment for this disease. PMID:26813102

  15. Human safety controversies surrounding nitrate and nitrite in the diet.

    PubMed

    Sindelar, Jeffrey J; Milkowski, Andrew L

    2012-05-15

    Nitrate and nitrite are part of the human diet as nutrients in many vegetables and part of food preservation systems. In the 1950s and 1960s the potential for formation of nitrosamines in food was discovered and it ignited a debate about the safety of ingested nitrite which ultimately focused on cured meats. Nitrate impurities in salt used in the drying of meat in ancient times resulted in improved protection from spoilage during storage. This evolved into their deliberate modern use as curing ingredient responsible for 'fixing' the characteristic color associated with cured meats, creating a unique flavor profile, controlling the oxidation of lipids, and serving as an effective antimicrobial. Several critical reports and comprehensive reviews reporting weak associations and equivocal evidence of nitrite human health safety have fostered concerns and debate among scientists, regulators, press, consumer groups, and consumers. Despite periodic controversy regarding human health concerns from nitrite consumption, a building base of scientific evidence about nitrate, nitrite, heme chemistry, and the overall metabolism of nitrogen oxides in humans has and continues to affirm the general safety of nitrate/nitrite in human health. As nitrite based therapeutics emerge, it is important to consider the past controversies and also understand the beneficial role in the human diet.

  16. Increased nitrite reductase activity of fetal versus adult ovine hemoglobin

    PubMed Central

    Blood, Arlin B.; Tiso, Mauro; Verma, Shilpa T.; Lo, Jennifer; Joshi, Mahesh S.; Azarov, Ivan; Longo, Lawrence D.; Gladwin, Mark T.; Kim-Shapiro, Daniel B.; Power, Gordon G.

    2009-01-01

    Growing evidence indicates that nitrite, NO2−, serves as a circulating reservoir of nitric oxide (NO) bioactivity that is activated during physiological and pathological hypoxia. One of the intravascular mechanisms for nitrite conversion to NO is a chemical nitrite reductase activity of deoxyhemoglobin. The rate of NO production from this reaction is increased when hemoglobin is in the R conformation. Because the mammalian fetus exists in a low-oxygen environment compared with the adult and is exposed to episodes of severe ischemia during the normal birthing process, and because fetal hemoglobin assumes the R conformation more readily than adult hemoglobin, we hypothesized that nitrite reduction to NO may be enhanced in the fetal circulation. We found that the reaction was faster for fetal than maternal hemoglobin or blood and that the reactions were fastest at 50–80% oxygen saturation, consistent with an R-state catalysis that is predominant for fetal hemoglobin. Nitrite concentrations were similar in blood taken from chronically instrumented normoxic ewes and their fetuses but were elevated in response to chronic hypoxia. The findings suggest an augmented nitrite reductase activity of fetal hemoglobin and that the production of nitrite may participate in the regulation of vascular NO homeostasis in the fetus. PMID:19028797

  17. Effectiveness of acidified sodium chlorite and other sanitizers to control Escherichia coli O157:H7 on tomato surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of a suitable sanitizer can reduce the risk of produce related food-borne illnesses. We evaluated the effectiveness of several sanitizers to reduce inoculated Escherichia coli O157:H7 on petit tomatoes. Depending on the method of inoculation (dipping / spotting), each of 80g of inoculated to...

  18. Thermal inactivation of Salmonella Typhimurium on dressed chicken skin previously exposed to acidified sodium chlorite or carvacrol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella is a leading cause of foodborne illness, and live poultry is a main reservoir of this pathogen. Cross-contamination and transportation of contaminated poultry meat act as an important vehicle of Salmonella infections in humans. In this study, we assessed the effect of two antimicrobials:...

  19. Short-term hypoxic vasodilation in vivo is mediated by bioactive nitric oxide metabolites, rather than free nitric oxide derived from haemoglobin-mediated nitrite reduction.

    PubMed

    Umbrello, Michele; Dyson, Alex; Pinto, Bernardo Bollen; Fernandez, Bernadette O; Simon, Verena; Feelisch, Martin; Singer, Mervyn

    2014-03-01

    Local increases in blood flow--'hypoxic vasodilation'--confer cellular protection in the face of reduced oxygen delivery. The physiological relevance of this response is well established, yet ongoing controversy surrounds its underlying mechanisms. We sought to confirm that early hypoxic vasodilation is a nitric oxide (NO)-mediated phenomenon and to study putative pathways for increased levels of NO, namely production from NO synthases, intravascular nitrite reduction, release from preformed stores and reduced deactivation by cytochrome c oxidase. Experiments were performed on spontaneously breathing, anaesthetized, male Wistar rats undergoing short-term systemic hypoxaemia, who received pharmacological inhibitors and activators of the various NO pathways. Arterial blood pressure, cardiac output, tissue oxygen tension and the circulating pool of NO metabolites (oxidation, nitrosation and nitrosylation products) were measured in plasma and erythrocytes. Hypoxaemia caused a rapid and sustained vasodilation, which was only partially reversed by non-selective NO synthase inhibition. This was associated with significantly lower plasma nitrite, and marginally elevated nitrate levels, suggestive of nitrite bioinactivation. Administration of sodium nitrite had little effect in normoxia, but produced significant vasodilation and increased nitrosylation during hypoxaemia that could not be reversed by NO scavenging. Methodological issues prevented assessment of the contribution, if any, of reduced deactivation of NO by cytochrome c oxidase. In conclusion, acute hypoxic vasodilation is an adaptive NO-mediated response conferred through bioactive metabolites rather than free NO from haemoglobin-mediated reduction of nitrite.

  20. Stability of α-tocotrienol and α-tocopherol in salami-type sausages and curing brine depending on nitrite and pH.

    PubMed

    Gerling, Eva-Maria; Ternes, Waldemar

    2014-12-01

    We studied the stability of the valuable vitamer nutrients α-tocotrienol and α-tocopherol and options for their protection in salami-type sausages (blended with α-tocotrienol-rich barley oil) and curing brine. Four different sausage formulations were produced containing nitrite curing salt; nitrite curing salt and ascorbic acid (300mg/kg); nitrite curing salt and carnosic acid (45mg/kg); or sodium chloride. Initial vitamer contents (100mg/kg) did not decrease significantly during ripening and decreased only slightly during storage. Ascorbic acid and carnosic acid were found to be effective in preserving the vitamers in fresh sausages. Freeze-drying of sausages resulted in a significant loss of vitamers (97%), particularly after 14-day storage at room temperature, even in the presence of shielding gases. The vitamer content in the curing brine decreased with decreasing pH in the presence of nitrite. A nitrite concentration of 136mg/L at pH4 resulted in significant loss (90%) of the vitamers. Sufficient stability of the vitamers in salami-type sausage and curing brine can be achieved by processing, formulation, and storage conditions.

  1. Cold-surface photochemistry of primary and tertiary alkyl nitrites.

    PubMed

    McLaughlin, Ryan P; O'Sullivan, Daniel; Sodeau, John R

    2012-06-28

    Reflection-absorption infrared spectroscopy (RAIRS) is used to explore the photochemistry of primary and tertiary alkyl nitrites deposited on a gold surface. The primary alkyl nitrites examined for this study were n-butyl, isobutyl, and isopentyl nitrite. These compounds showed qualitatively similar spectra to those observed in previous condensed-phase measurements. The photolysis of the primary nitrites involved the initial formation of an alkoxy radical and NO, followed by production of nitroxyl (HNO) and an aldehydic species. In addition, the formation of nitrous oxide, identified from its distinctive transition near 2230 cm(-1), was observed to form from the self-reaction of nitroxyl. The reaction rates for cis and trans conformer decay, as tracked through their intense N═O stretching modes, were found to be significantly different, potentially due to a structural bias that favors HNO formation for the initial trans conformer photoproducts over recombination. Tert-butyl nitrite demonstrates only the trans conformer in the RAIRS spectra prior to photolysis; however, recombination of the initial NO and RO(•) photoproducts was observed to produce the cis conformer in the photolyzed samples. The primary photoproducts from tert-butyl nitrite can also react to form acetone and nitrosomethane, but the absence of HNO prohibits the formation of N(2)O that was observed for the primary alkyl nitrites. Additionally, the RAIRS spectrum of isobutyl nitrite co-deposited with water was measured to examine the photolysis of this species on a water-ice surface. No change in the identity of the photoproducts was observed in this experiment, and minimal frequency shifting (1-3 cm(-1)) of the vibrational modes occurred. In addition to being a known atmospheric source of NO and various aldehydes, our results point to cold surface processing of alkyl nitrites as a potential environmental source of nitrous oxide.

  2. A comparison of organic and inorganic nitrates/nitrites.

    PubMed

    Omar, Sami A; Artime, Esther; Webb, Andrew J

    2012-05-15

    Although both organic and inorganic nitrates/nitrites mediate their principal effects via nitric oxide, there are many important differences. Inorganic nitrate and nitrite have simple ionic structures and are produced endogenously and are present in the diet, whereas their organic counterparts are far more complex, and, with the exception of ethyl nitrite, are all medicinally synthesised products. These chemical differences underlie the differences in pharmacokinetic properties allowing for different modalities of administration, particularly of organic nitrates, due to the differences in their bioavailability and metabolic profiles. Whilst the enterosalivary circulation is a key pathway for orally ingested inorganic nitrate, preventing an abrupt effect or toxic levels of nitrite and prolonging the effects, this is not used by organic nitrates. The pharmacodynamic differences are even greater; while organic nitrates have potent acute effects causing vasodilation, inorganic nitrite's effects are more subtle and dependent on certain conditions. However, in chronic use, organic nitrates are considerably limited by the development of tolerance and endothelial dysfunction, whereas inorganic nitrate/nitrite may compensate for diminished endothelial function, and tolerance has not been reported. Also, while inorganic nitrate/nitrite has important cytoprotective effects against ischaemia-reperfusion injury, continuous use of organic nitrates may increase injury. While there are concerns that inorganic nitrate/nitrite may induce carcinogenesis, direct evidence of this in humans is lacking. While organic nitrates may continue to dominate the therapeutic arena, this may well change with the increasing recognition of their limitations, and ongoing discovery of beneficial effects and specific advantages of inorganic nitrate/nitrite.

  3. Electrochemical Recovery of Sodium Hydroxide from Alkaline Salt Solution

    SciTech Connect

    Hobbs, D.T.; Edwards, T.B.

    1996-10-01

    A statistically designed set of tests determined the effects of current density, temperature, and the concentrations of nitrate/nitrite, hydroxide and aluminate on the recovery of sodium as sodium hydroxide (caustic) from solutions simulating those produced from the Savannah River Site (SRS) In-Tank Precipitation process. These tests included low nitrate and nitrite concentrations which would be produced by electrolytic nitrate/nitrite destruction. The tests used a two compartment electrochemical cell with a Nafion Type 324 ion-exchange membrane. Caustic was successfully recovered from the waste solutions. Evaluation of the testing results indicated that the transport of sodium across the membrane was not significantly affected by any of the varied parameters. The observed variance in the sodium flux is attributed to experimental errors and variations in the performance characteristics of individual pieces of the organic-based Nafion membrane.Additional testing is recommended to determine the maximum current density, to evaluate the chemical durability of the organic membrane as a function of current density and to compare the durability and performance characteristics of the organic-based Nafion membrane with that of other commercially available organic membranes and the inorganic class of membranes under development by Ceramatec and PNNL.

  4. The anoxic plant mitochondrion as a nitrite: NO reductase.

    PubMed

    Gupta, Kapuganti J; Igamberdiev, Abir U

    2011-07-01

    Under the conditions of oxygen deprivation, accumulating nitrite can be reduced in the mitochondrial electron transport chain forming free radical nitric oxide (NO). By reducing nitrite to NO, plant mitochondria preserve the capacity to oxidize external NADH and NADPH and retain a limited power for ATP synthesis complementing glycolytic ATP production. NO participates in O(2) balance in mitochondria by competitively inhibiting cytochrome c oxidase which can oxidize it to nitrite when oxygen concentration increases. Some of the NO escapes to the cytosol, where the efficient scavenging system involving non-symbiotic hemoglobin oxygenates NO to nitrate and supports continuous anaerobic turnover of nitrogen species.

  5. Fresh and preserved green fodder modify effects of urinary acidifiers on urine pH of horses.

    PubMed

    Goren, G; Fritz, J; Dillitzer, N; Hipp, B; Kienzle, E

    2014-04-01

    Hay stabilises urine pH in horses. It is unknown whether this is an effect of structure or of chemical composition. In this study, four ponies (230-384 kg body weight [BW]) were fed six different diets with either a structure or a composition similar to hay with and without acidifiers in a cross-over experimental design in amounts to maintain body weight with the following main compounds: Fresh grass (GRASS), alfalfa hay (ALF), grass cobs (COBS), grass silage (SIL), straw (STR) or extruded straw (STRe) for 2 to 10 days. Urine pH was measured in all trials, blood pH, blood base excess and bicarbonate as well as mineral balance were determined in GRASS, ALF, STR and STRe. In the trials with straw and extruded straw, urine pH decreased significantly (STR control: 7.8 ± 0.23, acidifier: 5.2 ± 0.38) when acidifiers were added, whereas in all other diets that were based on fresh or preserved green fodder, pH did not decrease below 7. Blood pH was similarly affected by diet and acidifiers. Acidifiers had little effect on the pre-prandial blood pH, only in diet STR there was a significant reduction in relation to control. Post-prandial blood pH was significantly reduced by acidifiers in all diets. Blood bicarbonate and base excess showed corresponding effects. Faecal and renal mineral excretion and apparent mineral digestibility were not systematically affected by diet or acidifiers except for chloride. Chloride added as inorganic chloride salt had an even better apparent digestibility than chloride originating from feed. Because only green plant material stabilised acid base balance, chlorophyll and its metabolites are discussed as potential mediators of the effect of green fodder on acid base balance.

  6. Partitioning and bioavailability of mercury in an experimentally acidified Wisconsin lake

    USGS Publications Warehouse

    Wiener, James G.; Fitzgerald, William F.; Watras, Carl J.; Rada, Ronald G.

    1990-01-01

    We studied the partitioning of mercury (Hg) among air, water, sediments and fish at Little Rock Lake, a clear water seepage lake in north-central Wisconsin. The lake was divided with a sea curtain into two basins, one acidified with sulfuric acid to pH 5.6 for two years and the other an untreated reference site (mean pH 6.1), to document the effects of acidification. Trace-metal-free protocols were used to measure Hg at the picomolar level in air and water. Total gaseous Hg in air samples averaged 2.0 ng/m3. Total Hg in unfiltered water samples collected in 1986 after the fall overturn averaged about 1 ng/L in the acidified and reference basins. Mercury in surficial sediments was strongly correlated with volatile matter content and ranged from 10 to about 170 ng/g (dry weight) in both basins. Total Hg concentrations in whole, calendar age-1 yellow perch (Perca flavescens), sampled after one year of residence in the lake, averaged 114 ng/g (fresh weight) in the reference basin and 135 ng/g in the acidified basin – a highly significant (p < 0.01) difference. The mean whole-body burden (quantity) of Hg in age-1 perch did not differ between basins after the first year, but was significantly greater in the treatment basin than in the reference basin after the second year of acidification. Differences between the two basins in the bioaccumulation of Hg were attributed to internal (within-lake) processes that influence the bioavailability of the metal. An initial Hg budget for the treatment basin of Little Rock Lake showed that atmospheric deposition and sedimentary remobilization of Hg are potentially important processes influencing its biogeochemical cycling and uptake by fish.

  7. 21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Nitrites and/or nitrates in curing premixes. 170... and Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are.... (b) Nitrites and/or nitrates, when packaged separately from flavoring and seasoning in...

  8. 21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Nitrites and/or nitrates in curing premixes. 170... and Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are.... (b) Nitrites and/or nitrates, when packaged separately from flavoring and seasoning in...

  9. 21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Nitrites and/or nitrates in curing premixes. 170... and Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are.... (b) Nitrites and/or nitrates, when packaged separately from flavoring and seasoning in...

  10. 21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nitrites and/or nitrates in curing premixes. 170.60... Decisions § 170.60 Nitrites and/or nitrates in curing premixes. (a) Nitrites and/or nitrates are food.... (b) Nitrites and/or nitrates, when packaged separately from flavoring and seasoning in...

  11. Metal accumulation and metallothionein concentrations in tree swallow nestlings near acidified lakes

    SciTech Connect

    St. Louis, V.; Breebaart, L. . Dept. of Zoology); Barlow, J.C. . Dept. of Zoology Royal Ontario Museum, Toronto, Ontario . Dept. of Ornithology); Klaverkamp, J.F. . Dept. of Fisheries and Oceans)

    1993-07-01

    The authors studied metal accumulation in hepatic and renal tissues of tree swallow (Tachycineta bicolor) nestlings at acidified and nonacid reference lakes in northwestern Ontario. Hepatic concentrations of metallothionein (metal-binding proteins, MT) in tree swallow nestlings were negatively correlated with pH of the nest-site lake. Combined concentrations of Cu and Zn in the liver were correlated with liver MT concentrations, but Cd was not. Although no overt signs of metal toxicity were observed in nestlings near acid lakes, the results clearly provided evidence that metals are transferred from acid lakes to birds and that these metals are correlated with increases in hepatic MT production.

  12. Solubilization and Resolution of the Membrane-Bound Nitrite Reductase from Paracoccus Halodenitrificans into Nitrite and Nitric Oxide Reductases

    NASA Technical Reports Server (NTRS)

    Grant, Michael A.; Cronin, Sonja E.; Hochstein, Lawrence I.

    1984-01-01

    Membranes prepared from Paracoccus halodenitrificans reduced nitrite or nitric oxide to nitrous oxide. Extraction of these membranes with the detergent CHAPSO [3-(3-Chlolamidoporopyldimethylammonio)-1-(2- hydroxy-1-propanesulfonate)], followed by ammonium sulfate fractionation of the solubilized proteins, resulted in the separation of nitrite and nitric oxide reductase activities. The fraction containing nitrite reductase activity spectrally resembled a cd-type cytochrome. Several cytochromes were detected in the nitric oxide reductase fraction. Which, if any, of these cytochromes is associated with the reduction of nitric oxide is not clear at this time.

  13. Influence of low levels of water salinity on toxicity of nitrite to anuran larvae.

    PubMed

    Shinn, C; Marco, A; Serrano, L

    2013-08-01

    Reactive nitrogen compounds such as nitrite (NO2(-)) are highly toxic to aquatic animals and are partly responsible for the global decline of amphibians. On some fish and Caudata amphibian species low levels of sodium chloride significantly reduce the toxicity of nitrite. However, the nitrite-salinity interaction has not been properly studied in anuran amphibians. To verify if chloride (Cl(-)) attenuates NO2(-) toxicity, eggs and larvae of three anuran species were subjected to a series of NO2(-) solutions combined with three salt concentrations (0, 0.4 and 2 or 0, 0.052 and 0.2gL(-1)NaCl). One of the species tested originated from two different populations inhabiting highly contrasted nutrient richness environments: lowland Doñana Natural Park and Sierra de Gredos Mountain. In general, the presence of Cl(-) increased survival and growth of lowland Pelophylax perezi and activity of mountain P. perezi larvae exposed to NO2(-), thus attenuating the toxicity of NO2(-) to developing amphibians. Mountain amphibian populations appeared to be much more sensitive to the concentrations of NO2(-) and Cl(-) used in this experiment than coastal conspecifics, suggesting possible adaptation of populations to local conditions. Nitrogen pollution in coastal wetlands poses a serious threat to aquatic organisms, causing direct toxicity or indirect effects via ecosystem eutrophication. The presence of low to medium levels of salinity that would be common in coastal wetlands may attenuate the direct effects of increasing concentrations of nitrogenous compounds in water bodies. Furthermore, treating cultures of endangered anurans with small amounts of NaCl may provide an additional protective measure.

  14. Achievement of high nitrite accumulation via endogenous partial denitrification (EPD).

    PubMed

    Ji, Jiantao; Peng, Yongzhen; Wang, Bo; Wang, Shuying

    2017-01-01

    This study proposed a novel strategy for achievement of partial denitrification driven by endogenous carbon sources in an anaerobic/anoxic/aerobic activated sludge system. Results showed that in the steady-stage, the nitrate-to-nitrite transformation ratio (NTR) was kept at around 87% without nitrate in the effluent. During the anaerobic period, exogenous carbon sources was completely taken up, accompanied by the consumption of glycogen and production of polyhydroxyalkanoates (PHAs). During the anoxic period, nitrate was reduced to nitrite by using PHAs as carbon sources, followed by the replenishment of glycogen. Thus, the phenotype of denitrifying GAOs was clearly observed and endogenous partial denitrification (EPD) occurred. Furthermore, results showed the nitrate reduction was prior to the nitrite reduction in the presence of nitrate, which led to the high nitrite accumulation.

  15. Nitrite as a candidate substrate in microbial fuel cells.

    PubMed

    Faraghi, Neda; Ebrahimi, Sirous

    2012-08-01

    Current generation using nitrite as substrate (pH 6.9, 40 mgN l(-1)) in a nitrite-fed microbial fuel cell was investigated under anaerobic and aerobic anodic conditions as an alternative to the biological nitrite oxidation process. Cell current, coulombic efficiency (CE) and power generation of 0.04 mA, 30 ± 2 % and 19.3 ± 3.3 μW m(-2), respectively, were observed under anaerobic conditions while complete nitrite degradation (no current) was obtained under aerobic conditions. Switching from aerobic to anaerobic anode enhanced the CE and power generation (39 ± 1 % and 29 ± 4.3 μW m(-2)).

  16. Hydroxocobalamin Versus Sodium Thiosulfate for the Treatment of Acute Cyanide Toxicity in a Swine (Sus scrofa) Model

    DTIC Science & Technology

    2012-06-01

    effective for smoke inhalation ? searching for guidance in the haze. Ann Emerg Med. 2007;49:814-816. 6. Velez LI, Delaney LS. Cyanide. In: Tintinalli JE, ed...than sodium nitrite. However, it is not clear whether the sodium thiosulfate adds a beneficial effect to hydroxocobalamin alone.3,6,11,12 Experts...This Investigation The primary hypothesis of our study is that sodium thiosulfate is as effective as hydroxocobalamin in reversing the hypotension

  17. Molecular Components of Nitrate and Nitrite Efflux in Yeast

    PubMed Central

    Cabrera, Elisa; González-Montelongo, Rafaela; Giraldez, Teresa; de la Rosa, Diego Alvarez

    2014-01-01

    Some eukaryotes, such as plant and fungi, are capable of utilizing nitrate as the sole nitrogen source. Once transported into the cell, nitrate is reduced to ammonium by the consecutive action of nitrate and nitrite reductase. How nitrate assimilation is balanced with nitrate and nitrite efflux is unknown, as are the proteins involved. The nitrate assimilatory yeast Hansenula polymorpha was used as a model to dissect these efflux systems. We identified the sulfite transporters Ssu1 and Ssu2 as effective nitrate exporters, Ssu2 being quantitatively more important, and we characterize the Nar1 protein as a nitrate/nitrite exporter. The use of strains lacking either SSU2 or NAR1 along with the nitrate reductase gene YNR1 showed that nitrate reductase activity is not required for net nitrate uptake. Growth test experiments indicated that Ssu2 and Nar1 exporters allow yeast to cope with nitrite toxicity. We also have shown that the well-known Saccharomyces cerevisiae sulfite efflux permease Ssu1 is also able to excrete nitrite and nitrate. These results characterize for the first time essential components of the nitrate/nitrite efflux system and their impact on net nitrate uptake and its regulation. PMID:24363367

  18. Nitrite-induced anemia in channel catfish, Ictalurus punctatus Rafinesque

    SciTech Connect

    Tucker, C.S. ); Francis-Floyd, R.; Beleau, M.H. )

    1989-08-01

    Since 1983 numerous cases of anemia have been reported in populations of channel catfish Ictalurus punctatus Rafinesque cultured in the southeastern United States. Environmental nitrite-nitrogen concentrations of 4 mg/L or more occur sporadically in channel catfish culture ponds, and the frequency of occurrence is greatest in the fall and spring. The authors have observed that some cases of anemia in populations of pond-raised channel catfish follow prolonged exposure to high concentrations of environmental nitrite. However, there was no evidence that exposure of channel catfish to environmental nitrite was the cause of the observed anemia. Hemolytic anemia following nitrite exposure has been described for sea bass Dicentrarchus labrax (L.) and rainbow trout Salmo gairdneri, but not for channel catfish. In the present study the authors show that a variable, but generally mild, anemia develops in channel catfish exposed to nitrite. They also offer a management procedure for preventing the development of anemia during periods of elevated environmental nitrite concentrations.

  19. Mutagenicity of some alkyl nitrites used as recreational drugs

    SciTech Connect

    Dunkel, V.C.; Cameron, T.P. ); Rogers-Back, A.M.; Lawlor, T.E.; Harbell, J.W. )

    1989-01-01

    When the AIDS epidemic was in its earliest stages, and prior to identification of HIV as the etiological factor, the use of volatile nitrites by the male homosexual community to enhance sexual activities appeared to have a significant role in this disease. Preliminary observations indicated that that portion of the male homosexual community which developed Kaposi's sarcoma were also heavy nitrite users. These nitrites had been demonstrated to be mutagenic in bacteria and thus it was postulated that they could be responsible for the appearance of the sarcoma. To evaluate further the genotoxic activity of these chemicals, six nitrites, including those most commonly used by homosexuals for sexual gratification, were selected for testing in the mouse lymphoma TK {plus minus} and Salmonell typhimurium mutagenicity assays. One chemical, n-amyl nitrite, was negative in the mouse lymphoma assay, while the other five chemicals, n-butyl, isobutyl, iso-amyl, sec-butyl, and n-propyl nitrite, were positive. All six compounds were positive in the Salmonella assay. The mutagenic and known toxic effects of these chemicals remain a concern because a large population of teenagers and young adults continue to abuse these substances.

  20. Inhibitory effect of nitrite on coagulation processes demonstrated by thrombelastography.

    PubMed

    Park, J W; Piknova, B; Nghiem, K; Lozier, J N; Schechter, A N

    2014-08-31

    Nitric oxide (NO) can be generated by two-step reduction pathway in which nitrate is converted first into nitrite and then into NO via several mechanisms, as well as from arginine by endogenous nitric oxide synthase (NOS). We have recently shown that nitrite ions in the presence of erythrocytes inhibit platelet aggregation and activation, as measured by aggregometry and flow cytometric analysis of P-selectin, through its reduction to NO under partially deoxygenated conditions. In the current study, we investigated how nitrite may affect overall clotting processes via modulating platelet function using thrombelastography (TEG). We measured three major TEG parameters, reaction time (R, time to initial fibrin formation), α angle (velocity of clot growth) and maximum amplitude (MA, maximum clot strength) using blood from healthy volunteers. An NO donor (DEANONOate) showed inhibitory effects on all TEG parameters in platelet rich plasma (PRP) and whole blood, resulting in delayed R, decreased angle, and reduced MA in a dose dependent manner. Nitrite ions also exhibited inhibitory effects in whole blood at 20% hematocrit, and this was greatly enhanced under hypoxic conditions, being demonstrable at 0.1 μM concentration. Neither compound changed any TEG parameters in plasma. Our results suggest that nitrite affects overall blood clotting and that TEG may be used to follow this process. Further the physiological effects of factors which determine NO bioavailability, such as endogenous levels of blood and tissue nitrite, may be useful as biomarkers for predicting hemostatic potential.

  1. On the chemical biology of the nitrite/sulfide interaction.

    PubMed

    Cortese-Krott, Miriam M; Fernandez, Bernadette O; Kelm, Malte; Butler, Anthony R; Feelisch, Martin

    2015-04-30

    Sulfide (H2S/HS(-)) has been demonstrated to exert an astounding breadth of biological effects, some of which resemble those of nitric oxide (NO). While the chemistry, biochemistry and potential pathophysiology of the cross-talk between sulfide and NO have received considerable attention lately, a comparable assessment of the potential biological implications of an interaction between nitrite and sulfide is lacking. This is surprising inasmuch as nitrite is not only a known bioactive oxidation product of NO, but also efficiently converted to S-nitrosothiols in vivo; the latter have been shown to rapidly react with sulfide in vitro, leading to formation of S/N-hybrid species including thionitrite (SNO(-)) and nitrosopersulfide (SSNO(-)). Moreover, nitrite is used as a potent remedy against sulfide poisoning in the clinic. The chemistry of interaction between nitrite and sulfide or related bioactive metabolites including polysulfides and elemental sulfur has been extensively studied in the past, yet much of this information appears to have been forgotten. In this review, we focus on the potential chemical biology of the interaction between nitrite and sulfide or sulfane sulfur molecules, calling attention to the fundamental chemical properties and reactivities of either species and discuss their possible contribution to the biology, pharmacology and toxicology of both nitrite and sulfide.

  2. Inhibitory effect of nitrite on coagulation processes demonstrated by thrombelastography

    PubMed Central

    Park, J. W.; Piknova, B.; Nghiem, K.; Lozier, J. N.; Schechter, A. N.

    2014-01-01

    Nitric oxide (NO) can be generated by two-step reduction pathway in which nitrate is converted first into nitrite and then into NO via several mechanisms, as well as from arginine by endogenous nitric oxide synthase (NOS). We have recently shown that nitrite ions in the presence of erythrocytes inhibit platelet aggregation and activation, as measured by aggregometry and flow cytometric analysis of P-selectin, through its reduction to NO under partially deoxygenated conditions. In the current study, we investigated how nitrite may affect overall clotting processes via modulating platelet function using thrombelastography (TEG). We measured three major TEG parameters, reaction time (R, time to initial fibrin formation), α angle (velocity of clot growth) and maximum amplitude (MA, maximum clot strength) using blood from healthy volunteers. An NO donor (DEANONOate) showed inhibitory effects on all TEG parameters in platelet rich plasma (PRP) and whole blood, resulting in delayed R, decreased angle, and reduced MA in a dose dependent manner. Nitrite ions also exhibited inhibitory effects in whole blood at 20% hematocrit, and this was greatly enhanced under hypoxic conditions, being demonstrable at 0.1 μM concentration. Neither compound changed any TEG parameters in plasma. Our results suggest that nitrite affects overall blood clotting and that TEG may be used to follow this process. Further the physiological effects of factors which determine NO bioavailability, such as endogenous levels of blood and tissue nitrite, may be useful as biomarkers for predicting hemostatic potential. PMID:24858214

  3. In-Line Acidification for Potentiometric Sensing of Nitrite in Natural Waters.

    PubMed

    Pankratova, Nadezda; Cuartero, Maria; Cherubini, Thomas; Crespo, Gaston A; Bakker, Eric

    2017-01-03

    We report on a novel approach for in-line sample acidification that results in a significant improvement in the limit of detection of potentiometric anion-selective electrodes aiming at determining nutrients in natural waters. The working principle of the developed acidification module relies on the cation-exchange process between the sample and an ion-exchange Donnan exclusion membrane in its protonated form. The resulting in-line acidification of natural waters with millimolar sodium chloride level (freshwater, drinking water, and aquarium water, as well as dechloridized seawater) decreases the pH down to ∼5. By using the acidification module, the limit of detection of nitrite-selective electrodes significantly improves by more than 2 orders of magnitude with respect to that observed at environmental pH. The originality of the proposed flow cell lies in the possibility to adjust the pH of the sample by modifying its exposure time with the membrane by varying the volumetric flow rate. Facile coupling with a detection technique of choice, miniaturized configuration and simple implementation for long-term monitoring with submersible probes for environmental analysis are possible analytical configurations. This approach was here successfully applied for the potentiometric detection of nitrite in aquarium and dechloridized seawater samples.

  4. Automated, colorimetric methods for determination of nitrate plus nitrite, nitrite, ammonium and orthophosphate ions in natural water samples

    USGS Publications Warehouse

    Antweiler, Ronald C.; Patton, Charles J.; Taylor, Howard E.

    1996-01-01

    The apparatus and methods used for the automatic, colorimetric determinations of dissolved nutrients (nitrate plus nitrite, nitrite, ammonium and orthophosphate) in natural waters are described. These techniques allow for the determination of nitrate plus nitrite for the concentration range 0.02 to 8 mg/L (milligrams per liter) as N (nitrogen); for nitrite, the range is 0.002 to 1.0 mg/L as N; for ammonium, the range is 0.006 to 2.0 mg/L as N; and for orthophosphate, the range is 0.002 to 1.0 mg/L as P (phosphorus). Data are presented that demonstrate the accuracy, precision and quality control of the methods.

  5. Protozoan grazing on bacteria at the sediment-water interface of an acidified lake

    SciTech Connect

    Tremaine, S.C.

    1988-01-01

    Protozoan grazing on bacteria has been hypothesized to link the detrital and grazer food chains in aquatic ecosystems. The current study of protozoan bacterivory, evaluated methods, quantified bacterivory, and evaluated the role of protozoa at the sediment-water interface of an acidified lake ecosystem, Lake Anna, Virginia. Three limnetic methods for determining protozoan bacterivory were tested for applicability at the sediment-water interface. The eucaryote inhibitor, cycloheximide, was found unsatisfactory because it did not uniformly inhibit growth of target eucaryotes, and because it inhibited non-target anaerobic procaryotes. The filtration method was found to have limited application in sediment systems due to filtrational loss of particle-associated bacteria. The dilution method was tested for violations of its critical assumptions: bacterial growth is exponential; grazing mortality is proportional to the dilution factor; and bacterial growth rates are unaltered under experimental conditions. These assumptions were found not to be violated, and this method was used in subsequent grazing experiments. Carbon loading to the acidified arm of Lake Anna was 41 {times} 10{sup 6} g C {times} y{sup {minus}1}. This appears to be adequate carbon loading to support bacterial production and, in turn, protozoan bacterivory and production. Though there is no direct evidence that zooplankton graze on protozoa in this system, however, there is sufficient protozoan production to support an additional trophic level.

  6. Growth and physiological condition of black ducks reared on acidified wetlands

    USGS Publications Warehouse

    Rattner, B.A.; Haramis, G.M.; Chu, D.S.; Bunck, C.M.; Scanes, C.G.

    1987-01-01

    Acid deposition has been identified as one of several possible factors contributing to the decline of some waterfowl populations in North America. In an effort to examine the effects of acidification on black duck (Anas rubripes) recruitment, growth and physiological condition were monitored in ducklings foraging for a 10-day trial (days 10-20 of life) on acidified (pH 5.0) and : circumneutral (pH 6.8) fish-free emergent wetlands. Acidification of these wetlands suppressed phytoplankton and algal growth, and reduced invertebrate biomass. Ducklings maintained on acidified wetlands grew poorly compared with ducklings reared on circumneutral wetlands, as evidenced by lower final body weight and culmen and tarsus length. Plasma growth hormone concentration was elevated and triiodothyronine levels were lower in stunted ducklings, in part substantiating impairment of growth-regulating processes. Ducklings exhibiting poor growth tended to have lower hematocrit, lower plasma protein, glucose, and cholesterol concentrations, and higher uric acid levels, presumably reflecting alterations in metabolism and development due to inanition. These findings suggest that acid deposition may lower food production in wetlands and ultimately impair duckling growth, condition, and survival.

  7. Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

    PubMed

    Moset, Veronica; Ottosen, Lars Ditlev Mørck; Xavier, Cristiane de Almeida Neves; Møller, Henrik Bjarne

    2016-05-15

    Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM. Important enhancement of methane (CH4) yield and solid reductions were observed in the thermophilic one-step CSTR working with 10% AcCM. However, a higher inclusion level of AcCM (20%) caused volatile fatty acid accumulation in the reactor and a more than 30% reduction in CH4 production. In terms of CH4 production, when 10% of AcCM was co-digested with 90% of CM, the two-step anaerobic co-digestion yielded less than the single step. During the first step of the two-step CSTR process, acidogenesis and a partial sulfate reduction were achieved. However, sulfide stripping between the first and the second step must be promoted in order to advance this technology.

  8. Esterification of acidified oil with methanol by SPES/PES catalytic membrane.

    PubMed

    Shi, Wenying; He, Benqiao; Li, Jianxin

    2011-05-01

    A sulfonated polyethersulfone (SPES)/polyethersulfone (PES) blend catalytic membrane was prepared and used as a heterogeneous catalyst in the esterification of the acidified oil (acid value 153 mg KOH/g) with methanol for producing biodiesel. The results showed that the free fatty acids conversion reached 97.6% using SPES/PES catalytic membrane under the optimal esterification conditions. Meanwhile, the SPES/PES membrane with 20.3% degree of sulfonation showed a good catalytic stability. A pseudo-homogeneous kinetic model was established. The results indicated that the reaction rate constant increased with increasing methanol/acidified oil molar ratio, the loading of catalytic membrane and reaction temperature. The reaction order was 2 and the activation energy decreased from 74.65 to 21.07 kJ/mol with increasing catalytic membrane loading from 0 to 0.135 meq/g(oil). It implies that the esterification is not diffusively controlled but kinetically controlled. The predicted results were in good agreement with the experimental data.

  9. Spatial community shift from hard to soft corals in acidified water

    NASA Astrophysics Data System (ADS)

    Inoue, Shihori; Kayanne, Hajime; Yamamoto, Shoji; Kurihara, Haruko

    2013-07-01

    Anthropogenic increases in the partial pressure of CO2 (pCO2) cause ocean acidification, declining calcium carbonate saturation states, reduced coral reef calcification and changes in the compositions of marine communities. Most projected community changes due to ocean acidification describe transitions from hard coral to non-calcifying macroalgal communities; other organisms have received less attention, despite the biotic diversity of coral reef communities. We show that the spatial distributions of both hard and soft coral communities in volcanically acidified, semi-enclosed waters off Iwotorishima Island, Japan, are related to pCO2 levels. Hard corals are restricted to non-acidified low- pCO2 (225μatm) zones, dense populations of the soft coral Sarcophyton elegans dominate medium- pCO2 (831μatm) zones, and both hard and soft corals are absent from the highest- pCO2 (1,465μatm) zone. In CO2-enriched culture experiments, high- pCO2 conditions benefited Sarcophyton elegans by enhancing photosynthesis rates and did not affect light calcification, but dark decalcification (negative net calcification) increased with increasing pCO2. These results suggest that reef communities may shift from reef-building hard corals to non-reef-building soft corals under pCO2 levels (550-970μatm) predicted by the end of this century, and that higher pCO2 levels would challenge the survival of some reef organisms.

  10. [Decoloration of reactive turquoise blue by acidified sludge-bentonite granule].

    PubMed

    Yue, Qin-Yan; Yuan, Ai-Juan; Li, Qian; Gao, Bao-Yu; Li, Jing

    2009-05-15

    Using sludge as pore-forming agent, bentonite granule was acidified by sulfuric acid solution as a decolorant. The specific surface area and SEM were performed to characterize the structure of samples, and the new acidified sludge-bentonite granule was applied to the decoloration of reactive turquoise blue. The influencing factors of pH value, dosage, reaction time and reaction temperature were studied on the removal of the dyes. The important thermodynamics parameters (DeltaH0, DeltaS0, DeltaG) and the activation energy Ea were also acquired by experiment data processing. The results indicated that the adsorption isotherm fitted the isothermal adsorption equations of Langmuir better than Freundlich. The adsorption dynamics followed the law of the pseudo-second order kinetic equation, while the adsorption rate is 313 K > 303 K > 293 K. The low value of Ea which is 5.52 kJ x mol(-1) shows that physical adsorption is primary. And DeltaH0 > TDeltaS0 means that the influence of enthalpy is more remarkable than the entropy in the activation reaction. DeltaG > 0 also means the chemical reactions are not spontaneous.

  11. Salivary thiocyanate/nitrite inhibits hydroxylation of 2-hydroxybenzoic acid induced by hydrogen peroxide/Fe(II) systems under acidic conditions: possibility of thiocyanate/nitrite-dependent scavenging of hydroxyl radical in the stomach.

    PubMed

    Takahama, Umeo; Oniki, Takayuki

    2004-11-18

    Formation of OH radicals in the stomach is possible by Fenton-type reactions, as gastric juice contains ascorbic acid (AA), iron ions and H2O2. An objective of the present study is to elucidate the effects of salivary SCN- and NO2- on the hydroxylation of salicylic acid which was induced by H2O2/Fe(II) and AA/H2O2/Fe(II) systems. Thiocyanate ion inhibited the hydroxylation of salicylic acid by the above systems in acidic buffer solutions and in acidified saliva. The inhibition by SCN- was deduced to be due to SCN- -dependent scavenging of OH radicals. Nitrite ion could enhance the SCN- -dependent inhibition of the hydroxylation induced by AA/H2O2/Fe(II) systems. The enhancement was suggested to be due to scavenging of OH radicals by NO which was formed by the reactions among AA, HNO2 and SCN- contained in the reaction mixture. The concentrations of SCN- and NO2-, which were effective for the inhibition, were in ranges of their normal salivary concentrations. These results suggest that salivary SCN- can cooperate with NO2- to protect stomach from OH radicals formed by AA/H2O2/Fe(II) systems under acidic conditions.

  12. Enhancement of iron(II)-dependent reduction of nitrite to nitric oxide by thiocyanate and accumulation of iron(II)/thiocyanate/nitric oxide complex under conditions simulating the mixture of saliva and gastric juice.

    PubMed

    Takahama, Umeo; Hirota, Sachiko

    2012-01-13

    Iron(III) ingested as a food component or supplement for iron deficiencies can react with salivary SCN(-) to produce Fe(SCN)(2+) and can be reduced to iron(II) by ascorbic acid in the stomach. Iron(II) generated in the stomach can react with salivary nitrite and SCN(-) to produce nitric oxide (NO) and FeSCN(+), respectively. The purpose of this investigation is to make clear the reactions among nitrite, SCN(-), iron ions, and ascorbic acid under conditions simulating the mixture of saliva and gastric juice. Iron(II)-dependent reduction of nitrite to NO was enhanced by SCN(-) in acidic buffer solutions, and the oxidation product of iron(II) reacted with SCN(-) to produce Fe(SCN)(2+). Almost all of the NO produced was autoxidized to N(2)O(3) under aerobic conditions. Iron(II)-dependent production of NO was also observed in acidified saliva. Under anaerobic conditions, NO transformed Fe(SCN)(2+) and FeSCN(+) to Fe(SCN)NO(+) in acidic buffer solutions. Fe(SCN)NO(+) was also formed under aerobic conditions when excess ascorbic acid was added to iron(II)/nitrite/SCN(-) systems in acidic buffer solutions and acidified saliva. The Fe(SCN)NO(+) formed was transformed to Fe(SCN)(2+) and iron(III) at pH 2.0 and pH 7.4, respectively, by O(2). Salivary glycoproteins could complex with iron(III) in the stomach preventing the formation of Fe(SCN)(2+). Ascorbic acid reduced iron(III) to iron(II) to react with nitrite and SCN(-) as described above. The above results suggest (i) that iron(II) can have toxic effects on the stomach through the formation of reactive nitrogen oxide species from NO when supplemented without ascorbic acid and through the formation of both reactive nitrogen oxide species and Fe(SCN)NO(+) when supplemented with ascorbic acid, and (ii) that the toxic effects of iron(III) seemed to be smaller than and similar to those of iron(II) when supplemented without and with ascorbic acid, respectively. Possible mechanisms that cause oxidative stress on the stomach

  13. Time-dependent depletion of nitrite in pork/beef and chicken meat products and its effect on nitrite intake estimation

    PubMed Central

    Merino, Leonardo; Darnerud, Per Ola; Toldrá, Fidel; Ilbäck, Nils-Gunnar

    2016-01-01

    ABSTRACT The food additive nitrite (E249, E250) is commonly used in meat curing as a food preservation method. Because of potential negative health effects of nitrite, its use is strictly regulated. In an earlier study we have shown that the calculated intake of nitrite in children can exceed the acceptable daily intake (ADI) when conversion from dietary nitrate to nitrite is included. This study examined time-dependent changes in nitrite levels in four Swedish meat products frequently eaten by children: pork/beef sausage, liver paté and two types of chicken sausage, and how the production process, storage and also boiling (e.g., simmering in salted water) and frying affect the initial added nitrite level. The results showed a steep decrease in nitrite level between the point of addition to the product and the first sampling of the product 24 h later. After this time, residual nitrite levels continued to decrease, but much more slowly, until the recommended use-by date. Interestingly, this continuing decrease in nitrite was much smaller in the chicken products than in the pork/beef products. In a pilot study on pork/beef sausage, we found no effects of boiling on residual nitrite levels, but frying decreased nitrite levels by 50%. In scenarios of time-dependent depletion of nitrite using the data obtained for sausages to represent all cured meat products and including conversion from dietary nitrate, calculated nitrite intake in 4-year-old children generally exceeded the ADI. Moreover, the actual intake of nitrite from cured meat is dependent on the type of meat source, with a higher residual nitrite levels in chicken products compared with pork/beef products. This may result in increased nitrite exposure among consumers shifting their consumption pattern of processed meats from red to white meat products. PMID:26743589

  14. Time-dependent depletion of nitrite in pork/beef and chicken meat products and its effect on nitrite intake estimation.

    PubMed

    Merino, Leonardo; Darnerud, Per Ola; Toldrá, Fidel; Ilbäck, Nils-Gunnar

    2016-01-01

    The food additive nitrite (E249, E250) is commonly used in meat curing as a food preservation method. Because of potential negative health effects of nitrite, its use is strictly regulated. In an earlier study we have shown that the calculated intake of nitrite in children can exceed the acceptable daily intake (ADI) when conversion from dietary nitrate to nitrite is included. This study examined time-dependent changes in nitrite levels in four Swedish meat products frequently eaten by children: pork/beef sausage, liver paté and two types of chicken sausage, and how the production process, storage and also boiling (e.g., simmering in salted water) and frying affect the initial added nitrite level. The results showed a steep decrease in nitrite level between the point of addition to the product and the first sampling of the product 24 h later. After this time, residual nitrite levels continued to decrease, but much more slowly, until the recommended use-by date. Interestingly, this continuing decrease in nitrite was much smaller in the chicken products than in the pork/beef products. In a pilot study on pork/beef sausage, we found no effects of boiling on residual nitrite levels, but frying decreased nitrite levels by 50%. In scenarios of time-dependent depletion of nitrite using the data obtained for sausages to represent all cured meat products and including conversion from dietary nitrate, calculated nitrite intake in 4-year-old children generally exceeded the ADI. Moreover, the actual intake of nitrite from cured meat is dependent on the type of meat source, with a higher residual nitrite levels in chicken products compared with pork/beef products. This may result in increased nitrite exposure among consumers shifting their consumption pattern of processed meats from red to white meat products.

  15. Base hydrolysis kinetics of HMX-based explosives using sodium carbonate

    SciTech Connect

    Bishop, R.L.; Skidmore, C.; Flesner, R.L.; Dell`orco, P.C.; Spontarelli, T.; Uher, K.J.; Kramer, J.F.; Bell, D.A.

    1996-07-01

    Sodium carbonate has been identified as a possible hydrolysis reagent for decomposing HMX-based explosives to water soluble, non-energetic products. In this study, the reaction kinetics of sodium carbonate hydrolysis are examined and a reaction model is developed. The rate of hydrolysis is reaction rate limited, opposed to mass transfer limited, up to 150{degrees}C. Greater than 99% of the explosive solids in powder form are destroyed in less than 10 minutes at a temperature of 150{degrees}C. The primary products from sodium carbonate hydrolysis are sodium nitrite, formate, nitrate, acetate, glycolate, hexamine, nitrogen gas, nitrous oxide, and ammonia.

  16. Sodium azide

    Integrated Risk Information System (IRIS)

    Sodium azide ; CASRN 26628 - 22 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  17. Acifluorfen, sodium

    Integrated Risk Information System (IRIS)

    Acifluorfen , sodium ; CASRN 62476 - 59 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcino

  18. Sodium cyanide

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 28 , 2010 , the assessment summary for sodium cyanide is included in the

  19. Sodium diethyldithiocarbamate

    Integrated Risk Information System (IRIS)

    Sodium diethyldithiocarbamate ; CASRN 148 - 18 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Non

  20. Sodium fluoroacetate

    Integrated Risk Information System (IRIS)

    Sodium fluoroacetate ; CASRN 62 - 74 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

  1. Oxidative release of nitrite from 2-nitrotoluene by a three-component enzyme system from Pseudomonas sp. strain JS42.

    PubMed

    An, D; Gibson, D T; Spain, J C

    1994-12-01

    Pseudomonas sp. strain JS42 utilizes 2-nitrotoluene (2NT) as the sole source of carbon and energy for growth. Intact cells catalyze the oxidation of 2NT to 3-methylcatechol and nitrite in a reaction that requires molecular oxygen. Cell extracts oxidized 2NT to 3-methylcatechol and nitrite in the presence of NAD(P)H and ferrous iron. Ion-exchange chromatography yielded three protein fractions (A, B, and C) which were all required for the oxidation of 2NT to 3-methylcatechol and nitrite. Component B (reductase2NT) catalyzed a NAD(P)H-dependent reduction of cytochrome c. Solutions of component A (ISP2NT) were brown and showed absorption maxima at 458 and 324 nm. Two major bands with M(r)s 52,500 and 28,000 were observed when ISP2NT was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Component C could be replaced by ferredoxin NAP from the Pseudomonas putida NCIB 9816-4 naphthalene dioxygenase system and was given the designation ferredoxin2NT. Experiments with 18O2 showed that both oxygen atoms were added to the aromatic ring of 2NT to yield 3-methylcatechol. The enzyme is a new multicomponent enzyme system which we have designated 2NT 2,3-dioxygenase.

  2. Oxidative release of nitrite from 2-nitrotoluene by a three-component enzyme system from Pseudomonas sp. strain JS42.

    PubMed Central

    An, D; Gibson, D T; Spain, J C

    1994-01-01

    Pseudomonas sp. strain JS42 utilizes 2-nitrotoluene (2NT) as the sole source of carbon and energy for growth. Intact cells catalyze the oxidation of 2NT to 3-methylcatechol and nitrite in a reaction that requires molecular oxygen. Cell extracts oxidized 2NT to 3-methylcatechol and nitrite in the presence of NAD(P)H and ferrous iron. Ion-exchange chromatography yielded three protein fractions (A, B, and C) which were all required for the oxidation of 2NT to 3-methylcatechol and nitrite. Component B (reductase2NT) catalyzed a NAD(P)H-dependent reduction of cytochrome c. Solutions of component A (ISP2NT) were brown and showed absorption maxima at 458 and 324 nm. Two major bands with M(r)s 52,500 and 28,000 were observed when ISP2NT was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Component C could be replaced by ferredoxin NAP from the Pseudomonas putida NCIB 9816-4 naphthalene dioxygenase system and was given the designation ferredoxin2NT. Experiments with 18O2 showed that both oxygen atoms were added to the aromatic ring of 2NT to yield 3-methylcatechol. The enzyme is a new multicomponent enzyme system which we have designated 2NT 2,3-dioxygenase. Images PMID:8002568

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

    PubMed Central

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

    2010-01-01

    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. PMID:20805993

  4. Nitrite reduction mechanism on a Pd surface.

    PubMed

    Shin, Hyeyoung; Jung, Sungyoon; Bae, Sungjun; Lee, Woojin; Kim, Hyungjun

    2014-11-04

    Nitrate (NO3-) is one of the most harmful contaminants in the groundwater, and it causes various health problems. Bimetallic catalysts, usually palladium (Pd) coupled with secondary metallic catalyst, are found to properly treat nitrate-containing wastewaters; however, the selectivity toward N2 production over ammonia (NH3) production still requires further improvement. Because the N2 selectivity is determined at the nitrite (NO2-) reduction step on the Pd surface, which occurs after NO3- is decomposed into NO2- on the secondary metallic catalyst, we here performed density functional theory (DFT) calculations and experiments to investigate the NO2- reduction pathway on the Pd surface activated by hydrogen. Based on extensive DFT calculations on the relative energetics among ∼100 possible intermediates, we found that NO2- is easily reduced to NO* on the Pd surface, followed by either sequential hydrogenation steps to yield NH3 or a decomposition step to N* and O* (an adsorbate on Pd is denoted using an asterisk). Based on the calculated high migration barrier of N*, we further discussed that the direct combination of two N* to yield N2 is kinetically less favorable than the combination of a highly mobile H* with N* to yield NH3. Instead, the reduction of NO2- in the vicinity of the N* can yield N2O* that can be preferentially transformed into N2 via diverse reaction pathways. Our DFT results suggest that enhancing the likelihood of N* encountering NO2- in the solution phase before combination with surface H* is important for maximizing the N2 selectivity. This is further supported by our experiments on NO2- reduction by Pd/TiO2, showing that both a decreased H2 flow rate and an increased NO2- concentration increased the N2 selectivity (78.6-93.6% and 57.8-90.9%, respectively).

  5. Increased Salivary Nitrite and Nitrate Excretion in Rats with Cirrhosis.

    PubMed

    Mahmoodi, Somayeh; Rahmatollahi, Mahdieh; Shahsavari, Fatemeh; Shafaroodi, Hamed; Grayesh-Nejad, Siyavash; Dehpour, Ahmad R

    2015-11-01

    Increased nitric oxide (NO) formation is mechanistically linked to pathophysiology of the extrahepatic complications of cirrhosis. NO is formed by either enzymatic or non-enzymatic pathways. Enzymatic production is catalyzed by NO synthase (NOS) while entero-salivary circulation of nitrate and nitrite is linked to non-enzymatic formation of NO under acidic pH in the stomach. There is no data on salivary excretion of nitrate and nitrite in cirrhosis. This study was aimed to investigate salivary levels of nitrate and nitrite in a rat model of biliary cirrhosis. Cirrhosis was induced by bile duct ligation (BDL). Four weeks after the operation, submandibular ducts of anesthetized BDL and control rats were cannulated with polyethylene microtube for saliva collection. Assessment of pH, nitrite and nitrate levels was performed in our research. We also investigated NOS expression by real time RT-PCR to estimate eNOS, nNOS and iNOS mRNA levels in the submandibular glands. Salivary pH was significantly lower in BDL rats in comparison to control animals. We also observed a statistically significant increase in salivary levels of nitrite as well as nitrate in BDL rats while there was no elevation in the mRNA expression of nNOS, eNOS, and iNOS in submandibular glands of cirrhotic groups. This indicates that an increased salivary level of nitrite/nitrate is less likely to be linked to increased enzymatic production of NO in the salivary epithelium. It appears that nitrate/nitrite can be transported from the blood stream by submandibular glands and excreted into saliva as entero-salivary circulation, and this mechanism may have been exaggerated during cirrhosis.

  6. Test Your Sodium Smarts

    MedlinePlus

    ... You may be surprised to learn how much sodium is in many foods. Sodium, including sodium chloride ... foods with little or no salt. Test your sodium smarts by answering these 10 questions about which ...

  7. Formation of DNA-damaging N-nitroso compounds from the interaction of calcium-channel blockers with nitrite.

    PubMed

    Martelli, Antonietta; Robbiano, Luigi; Grossi, Sarah; Mattioli, Francesca; Brambilla, Giovanni

    2007-09-05

    A large number of drugs have been shown to react with nitrite to give genotoxic-carcinogenic N-nitroso compounds (NOC). However, the majority of drugs remain to be examined in this respect, among which calcium-channel blockers, all theoretically nitrosatable and widely used in the therapy of hypertension and other cardiovascular diseases. In this preliminary investigation, seven calcium-channel blockers have been examined either for their in vitro nitrosation according to the procedure recommended by the WHO, or for occurrence of liver DNA fragmentation, as detected by the Comet assay, in rats given by gavage 1/2 LD50 of the drug and 80 mg/kg of sodium nitrite. After 6h incubation the yields of NOC formed in vitro from nicardipine, nifedipine, nimodipine and nitrendipine ranged from 37 to 45% of the theoretical one, whereas the yields of NOC formed from diltiazem, gallopamil and verapamil ranged from 2 to 5%. In vivo, as compared with the effect of the same dose of the drug alone, a significant increase of both tail length and tail moment, indicative of an increased frequency of DNA single-strand breaks and alkali-labile sites, was produced in rat liver DNA by the administration with nitrite of gallopamil, nifedipine, nimodipine and nitrendipine, the ratio [tail length of drug+NaNO(2)/tail length of drug alone] being 3.2 for nimodipine, 3.1 for gallopamil 2.2 for nifedipine, and 2.1 for nitrendipine. Even if present, the increase in the degree of DNA fragmentation did not reach the statistical significance in rats given with nitrite nicardipine, diltiazem and verapamil. Further studies should be performed to investigate the formation of NOC in conditions simulating those occurring in the stomach of humans treated with a therapeutic dose, and to quantitate their genotoxic potency.

  8. Impact of mitochondria on nitrite metabolism in HL-1 cardiomyocytes

    PubMed Central

    Dungel, Peter; Teuschl, Andreas H.; Banerjee, Asmita; Paier-Pourani, Jamile; Redl, Heinz; Kozlov, Andrey V.

    2013-01-01

    Apart from ATP synthesis mitochondria have many other functions, one being nitrite reductase activity. Nitric oxide (NO) released from nitrite has been shown to protect the heart from ischemia/reperfusion (I/R) injury in a cGMP-dependent manner. However, the exact impact of mitochondria on the release of NO from nitrite in cardiomyocytes is not completely understood. Besides mitochondria, a number of non-mitochondrial metalloproteins have been suggested to facilitate this process. The aim of this study was to investigate the impact of mitochondria on the bioactivation of nitrite in HL-1 cardiomyocytes. The levels of nitrosyl complexes of hemoglobin (NO-Hb) and cGMP levels were measured by electron spin resonance spectroscopy and enzyme immunoassay. In addition the formation of free NO was determined by confocal microscopy as well as intracellular nitrite and S-nitrosothiols by chemoluminescence analysis. NO was released from nitrite in cell culture in an oxygen-dependent manner. Application of specific inhibitors of the respiratory chain, p450, NO synthases (NOS) and xanthine oxidoreductase (XOR) showed that all four enzymatic systems are involved in the release of NO, but more than 50% of NO is released via the mitochondrial pathway. Only NO released by mitochondria activated cGMP synthesis. Cardiomyocytes co-cultured with red blood cells (RBC) competed with RBC for nitrite, but free NO was detected only in HL-1 cells suggesting that RBC are not a source of NO in this model. Apart from activation of cGMP synthesis, NO formed in HL-1 cells diffused out of the cells and formed NO-Hb complexes. In addition nitrite was converted by HL-1 cells to S-nitrosyl complexes. In HL-1 cardiomyocytes, several enzymatic systems are involved in nitrite reduction to NO but only the mitochondrial pathway of NO release activates cGMP synthesis. Our data suggest that this pathway may be a key regulator of myocardial contractility especially under hypoxic conditions. PMID:23730288

  9. Leukocyte esterase-nitrite and bioluminescence assays as urine screens.

    PubMed Central

    Males, B M; Bartholomew, W R; Amsterdam, D

    1985-01-01

    The 1-min leukocyte esterase (LE)-nitrite test (Chemstrip 9; Biodynamics, Division of Boehringer Mannheim Biochemicals, Indianapolis, Ind.) and a bioluminescence assay (Monolight centrifugation method; Analytical Luminescence Laboratory, Inc., San Diego, Calif.) were tested for their efficacy as urine screens among 453 patients at a tertiary-care teaching hospital. Both methods had the capacity to exclude significant bacteriuria (greater than or equal to 10(5) CFU/ml) when compared with the results of conventional culture methods, with predictive values of 99 and 93%, respectively, for a negative test. Bioluminescence was the more accurate nonculture method used. Sensitivity and specificity values were 97 and 71%, respectively, for bioluminescence, 82 and 60%, respectively, for LE with nitrite, and 72 and 64%, respectively, for LE without nitrite. At reduced levels of bacteriuria less than 10(5) CFU/ml), the sensitivities of LE-nitrite and bioluminescence were decreased but comparable. The addition of protein and blood test results in the Chemstrip 9, along with LE-nitrite as bacteriuria indicators, were unsatisfactory because of the large numbers of false-positive results attributed to protein and blood determinations. LE activity as detected by the LE test was a poor predictor of significant bacteriuria in both male and female patients. The sensitivity (71%) and specificity (57%) of the LE test in male patients were significantly lower than those previously reported and varied with the patient population studied. PMID:3935662

  10. Human Neuroglobin Functions as a Redox-regulated Nitrite Reductase*

    PubMed Central

    Tiso, Mauro; Tejero, Jesús; Basu, Swati; Azarov, Ivan; Wang, Xunde; Simplaceanu, Virgil; Frizzell, Sheila; Jayaraman, Thottala; Geary, Lisa; Shapiro, Calli; Ho, Chien; Shiva, Sruti; Kim-Shapiro, Daniel B.; Gladwin, Mark T.

    2011-01-01

    Neuroglobin is a highly conserved hemoprotein of uncertain physiological function that evolved from a common ancestor to hemoglobin and myoglobin. It possesses a six-coordinate heme geometry with proximal and distal histidines directly bound to the heme iron, although coordination of the sixth ligand is reversible. We show that deoxygenated human neuroglobin reacts with nitrite to form nitric oxide (NO). This reaction is regulated by redox-sensitive surface thiols, cysteine 55 and 46, which regulate the fraction of the five-coordinated heme, nitrite binding, and NO formation. Replacement of the distal histidine by leucine or glutamine leads to a stable five-coordinated geometry; these neuroglobin mutants reduce nitrite to NO ∼2000 times faster than the wild type, whereas mutation of either Cys-55 or Cys-46 to alanine stabilizes the six-coordinate structure and slows the reaction. Using lentivirus expression systems, we show that the nitrite reductase activity of neuroglobin inhibits cellular respiration via NO binding to cytochrome c oxidase and confirm that the six-to-five-coordinate status of neuroglobin regulates intracellular hypoxic NO-signaling pathways. These studies suggest that neuroglobin may function as a physiological oxidative stress sensor and a post-translationally redox-regulated nitrite reductase that generates NO under six-to-five-coordinate heme pocket control. We hypothesize that the six-coordinate heme globin superfamily may subserve a function as primordial hypoxic and redox-regulated NO-signaling proteins. PMID:21296891

  11. Dissimilatory Nitrite Reductase Genes from Autotrophic Ammonia-Oxidizing Bacteria

    PubMed Central

    Casciotti, Karen L.; Ward, Bess B.

    2001-01-01

    The presence of a copper-containing dissimilatory nitrite reductase gene (nirK) was discovered in several isolates of β-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. Amplification products of the expected size were cloned and sequenced. Alignment of the nucleic acid and deduced amino acid (AA) sequences shows significant similarity (62 to 75% DNA, 58 to 76% AA) between nitrite reductases present in these nitrifiers and the copper-containing nitrite reductase found in classic heterotrophic denitrifiers. While the presence of a nitrite reductase in Nitrosomonas europaea is known from early biochemical work, preliminary sequence data from its genome indicate a rather low similarity to the denitrifier nirKs. Phylogenetic analysis of the partial nitrifier nirK sequences indicates that the topology of the nirK tree corresponds to the 16S rRNA and amoA trees. While the role of nitrite reduction in the metabolism of nitrifying bacteria is still uncertain, these data show that the nirK gene is present in closely related nitrifying isolates from many oceanographic regions and suggest that nirK sequences retrieved from the environment may include sequences from ammonia-oxidizing bacteria. PMID:11319103

  12. Nitrite as regulator of hypoxic signaling in mammalian physiology

    PubMed Central

    van Faassen, Ernst E.; Bahrami, Soheyl; Feelisch, Martin; Hogg, Neil; Kelm, Malte; Kim-Shapiro, Daniel B.; Kozlov, Andrey V.; Li, Haitao; Lundberg, Jon O.; Mason, Ron; Nohl, Hans; Rassaf, Tienush; Samouilov, Alexandre; Slama-Schwok, Anny; Shiva, Sruti; Vanin, Anatoly F.; Weitzberg, Eddie; Zweier, Jay; Gladwin, Mark T.

    2009-01-01

    In this review we consider the physiological effects of endogenous and pharmacological levels of nitrite under conditions of hypoxia. In humans, the nitrite anion has long been considered as metastable intermediate in the oxidation of nitric oxide radicals to the stable metabolite nitrate. This oxidation cascade was thought to be irreversible under physiological conditions. However, a growing body of experimental observations attests that the presence of endogenous nitrite regulates a number of signaling events along the physiological and pathophysiological oxygen gradient. Hypoxic signaling events include vasodilation, modulation of mitochondrial respiration, and cytoprotection following ischemic insult. These phenomena are attributed to the reduction of nitrite anions to nitric oxide if local oxygen levels in tissues decrease. Recent research identified a growing list of enzymatic and non-enzymatic pathways for this endogenous reduction of nitrite. Additional direct signaling events not involving free nitric oxide are proposed. We here discuss the mechanisms and properties of these various pathways and the role played by the local concentration of free oxygen in the affected tissue. PMID:19219851

  13. Low sodium diet (image)

    MedlinePlus

    ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, or ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, or ...

  14. Type C bovine botulism outbreak due to carcass contaminated non-acidified silage.

    PubMed

    Myllykoski, J; Lindström, M; Keto-Timonen, R; Söderholm, H; Jakala, J; Kallio, H; Sukura, A; Korkeala, H

    2009-02-01

    The first reported bovine botulism outbreak in Finland is described. Nine out of 90 cattle on a dairy farm died after being fed non-acidified silage contaminated by animal carcasses. Type C botulinum neurotoxin gene was detected in one heifer by polymerase chain reaction (PCR) and the neurotoxin was detected by the mouse bioassay. Clostridium botulinum type C was isolated from liver samples. The isolated strain was identified with amplified fragment length polymorphism (AFLP) analysis as group III C. botulinum. To our knowledge, this is the first time that a type C bovine botulism outbreak has been diagnosed by PCR and confirmed by subsequent isolation and AFLP identification of the disease strain. The importance of the acidification process in silage production to inhibit C. botulinum toxin production in silage and thus to prevent further botulism outbreaks is emphasized. Nevertheless, preformed toxin in the carcass is not destroyed by acid.

  15. Rapid restoration of methanogenesis in an acidified UASB reactor treating 2,4,6-trichlorophenol (TCP).

    PubMed

    Díaz-Báez, María Consuelo; Valderrama-Rincon, Juan Daniel

    2017-02-15

    Anaerobic bioreactors are often used for removal of xenobiotic and highly toxic pollutants from wastewater. Most of the time, the pollutant is so toxic that the stability of the reactor becomes compromised. It is well known that methanogens are one of the most sensitive organisms in the anaerobic consortia and hence the stability of the reactors is highly dependant on methanogenesis. Unfortunately few studies have focused on recovering the methanogenic activity once it has been inhibited by highly toxic pollutants. Here we establish a quick recovery strategy for neutralization of an acidified UASB reactor after failure by intoxication with an excess of TCP in the influent. Once the reactor returned to pH values compatible with methanogenesis, biogas production was re-started after one day and the system was re-acclimated to TCP. Successful removal of TCP from synthetic wastewater was shown for concentrations up to 70mg/L after restoration.

  16. Purification of empty fruit bunch (EFB) and kenaf soda lignin with acidified water

    NASA Astrophysics Data System (ADS)

    Hashim, Sharifah Nurul Ain Syed; Zakaria, Sarani; Jaafar, Sharifah Nabihah Syed; Hua, Chia Chin

    2014-09-01

    In this current study, the soda lignins from empty fruit bunch (EFB) and kenaf core were recovered by two step precipitation method. The objective of this research is to study the purity of lignin by washing the lignins with acidified water. The purified lignins were undergone characterization by FT-IR, Uv-Vis and XRD. The FT-IR analysis shows that kenaf core has Guaiacyl(G) and Syringyl(S) unit meanwhile EFB has Hydroxyphenyl(H), Guaiacyl(G) and Syringyl(S) unit of lignin. As for XRD analysis, the non-purified shows that the existence of impurities which is salt (NaCl). The UV analysis shows the higher absorbance which lead to the purity of lignin.

  17. Ammonification in Bacillus subtilis Utilizing Dissimilatory Nitrite Reductase Is Dependent on resDE

    PubMed Central

    Hoffmann, Tamara; Frankenberg, Nicole; Marino, Marco; Jahn, Dieter

    1998-01-01

    During anaerobic nitrate respiration Bacillus subtilis reduces nitrate via nitrite to ammonia. No denitrification products were observed. B. subtilis wild-type cells and a nitrate reductase mutant grew anaerobically with nitrite as an electron acceptor. Oxygen-sensitive dissimilatory nitrite reductase activity was demonstrated in cell extracts prepared from both strains with benzyl viologen as an electron donor and nitrite as an electron acceptor. The anaerobic expression of the discovered nitrite reductase activity was dependent on the regulatory system encoded by resDE. Mutation of the gene encoding the regulatory Fnr had no negative effect on dissimilatory nitrite reductase formation. PMID:9422613

  18. Eubiotic effect of a dietary acidifier (potassium diformate) on the health status of cultured Oreochromis niloticus.

    PubMed

    Abu Elala, Nermeen M; Ragaa, Naela M

    2015-07-01

    In connection with the global demand for safe human food and the production of environmentally friendly aquaculture products, acidifiers are natural organic acids and salts that have received considerable attention as animal-feed additives. The current study was designed to evaluate the effects of potassium diformate (KDF) on the growth performance and immunity of cultured Oreochromis niloticus (O. niloticus). Four iso-nitrogenous and iso-caloric rations containing graded levels of KDF, including 0% (control basal diet), 0.1%, 0.2% and 0.3%, were fed separately to four equal fish groups (30 fish/group with an initial body weight of 53.49 ± 6.15 g) for sixty days. At the end of the experimental period, the fish groups fed on 0.2% and 0.3% KDF exhibited significant improvements in their feed intake, live weight gain, specific growth rate, feed conversion ratio and protein efficiency ratio, with concomitant improvement of their apparent protein digestibility (p < 0.05). Dietary supplementation of 0.3% KDF appeared to stimulate the beneficial intestinal flora; a proliferation was observed of indigenous probionts (Eubiosis) associated with the relative activation of cellular and humeral innate immunity (phagocytic activity/index, nitroblue tetrazolium reduction test and serum/gut mucous lysozyme activity). The cumulative mortality of the fish groups fed on KDF and challenged orally with Aeromonas hydrophila was lower than that of the control group. The resistance against diseases increased with dietary KDF in a dose-dependent manner. Thus, we conclude that the use of acidifiers can be an efficient tool to achieve sustainable, economical and safe fish production.

  19. Eubiotic effect of a dietary acidifier (potassium diformate) on the health status of cultured Oreochromis niloticus

    PubMed Central

    Abu Elala, Nermeen M.; Ragaa, Naela M.

    2014-01-01

    In connection with the global demand for safe human food and the production of environmentally friendly aquaculture products, acidifiers are natural organic acids and salts that have received considerable attention as animal-feed additives. The current study was designed to evaluate the effects of potassium diformate (KDF) on the growth performance and immunity of cultured Oreochromis niloticus (O. niloticus). Four iso-nitrogenous and iso-caloric rations containing graded levels of KDF, including 0% (control basal diet), 0.1%, 0.2% and 0.3%, were fed separately to four equal fish groups (30 fish/group with an initial body weight of 53.49 ± 6.15 g) for sixty days. At the end of the experimental period, the fish groups fed on 0.2% and 0.3% KDF exhibited significant improvements in their feed intake, live weight gain, specific growth rate, feed conversion ratio and protein efficiency ratio, with concomitant improvement of their apparent protein digestibility (p < 0.05). Dietary supplementation of 0.3% KDF appeared to stimulate the beneficial intestinal flora; a proliferation was observed of indigenous probionts (Eubiosis) associated with the relative activation of cellular and humeral innate immunity (phagocytic activity/index, nitroblue tetrazolium reduction test and serum/gut mucous lysozyme activity). The cumulative mortality of the fish groups fed on KDF and challenged orally with Aeromonas hydrophila was lower than that of the control group. The resistance against diseases increased with dietary KDF in a dose-dependent manner. Thus, we conclude that the use of acidifiers can be an efficient tool to achieve sustainable, economical and safe fish production. PMID:26199753

  20. Fatty acid composition and biogenic amines in acidified and fermented fish silage: a comparison study.

    PubMed

    Özyurt, Gülsün; Gökdoğan, Saadet; Şimşek, Ayşe; Yuvka, Ilknur; Ergüven, Merve; Kuley Boga, Esmeray

    2016-01-01

    In the presented study, ensiling of discard fish by acidification or fermentation was evaluated. Klunzinger's ponyfish which is a discard fish was used for the production of fish silage by acidification (3% formic acid for Method FA; 1.5% formic and 1.5% sulphuric acid for Method FASA) and fermentation (Lactobacillus plantarum for Method LP and Streptococcus thermophilus for Method ST). The chemical, microbiological and nutritional properties of the differently preserved fish silages were estimated during a storage period of 60 d at ambient temperature. Compared to the raw material, a slight increase in saturated fatty acids and a slight decrease in polyunsaturated fatty acids were observed in all silages. At the end of the storage period, the aerobic bacteria counts after applying Methods FA, FASA, LP and ST amounted to 2.35, 2.39, 5.77 and 5.43 log cfu/g, respectively. The analysis of thiobarbituric acid revealed that acidification of silages accelerated the lipid oxidation. Nine biogenic amines were found in raw fish and different silages. The initial histamine concentration in raw fish was 0.17 mg/100 g and in all silages it remained at low levels during the storage period. The initial tyramine content was found to be 1.56 mg/100 g in raw fish and increased significantly in all silages. The increase of the tyramine content in fermented silages was considerably higher than in acidified silages (23-48 mg/100 g and 5-10 mg/100 g, respectively). It can be concluded that acidified or fermented fish silage should be considered as potential feed component for animals because of its high nutritional value and appropriate microbiological and chemical quality.

  1. Study of acidified ignitable liquid residues in fire debris by solid-phase microextraction with gas chromatography and mass spectrometry.

    PubMed

    Martín-Alberca, Carlos; García-Ruiz, Carmen; Delémont, Olivier

    2015-07-14

    The detection and identification of ignitable liquid residues in fire debris can be meaningful in fire investigations. However, background pyrolysis products and weathering hinder the identification and classification steps. In addition to those processes, the acidification of the ignitable liquids before the combustion process could make those tasks even more difficult. Nevertheless, there are no systematic studies assessing the extraction, analysis and composition of acidified ignitable liquid residues obtained from fire debris. In this work, a methodology for the study of acidified ignitable liquid residues in fire debris by solid-phase microextraction with gas chromatography and mass spectrometry is proposed. This methodology has been evaluated, first with simulated solutions (gasoline-sulphuric acid mixtures set on fire under controlled conditions), and then with analysis of samples from real fire debris obtained from 18 chemical ignition Molotov cocktails made with sulfuric acid and three different ignitable liquids (two types of gasoline and diesel fuel). In addition, the extensive modifications observed in chromatograms of acidified ignitable liquid residues regarding neat and weathered samples were studied. These alterations were produced by the combustion and acidification processes. As a consequence, tert-butylated compounds are proposed as diagnostic indicators for the identification of acidified gasoline in fire debris, even in strongly weathered samples. This article is protected by copyright. All rights reserved.

  2. Comparison of the effects of thermal stress and CO₂-driven acidified seawater on fertilization in coral Acropora digitifera.

    PubMed

    Iguchi, Akira; Suzuki, Atsushi; Sakai, Kazuhiko; Nojiri, Yukihiro

    2015-08-01

    Global warming (GW) and ocean acidification (OA) have been recognized as severe threats for reef-building corals that support coral reef ecosystems, but these effects on the early life history stage of corals are relatively unknown compared with the effects on calcification of adult corals. In this study, we evaluated the effects of thermal stress and CO2-driven acidified seawater on fertilization in a reef-building coral, Acropora digitifera. The fertilization rates of A. digitifera decreased in response to thermal stress compared with those under normal seawater conditions. In contrast, the changes of fertilization rates were not evident in the acidified seawater. Generalized Linear Mixed Model (GLMM) predicted that sperm/egg crosses and temperature were explanatory variables in the best-fitted model for the fertilization data. In the best model, interactions between thermal stress and acidified seawater on the fertilization rates were not selected. Our results suggested that coral fertilization is more sensitive to future GW than OA. Taking into consideration the previous finding that sperm motility of A. digitifera was decreased by acidified seawater, the decrease in coral cover followed by that of sperm concentration might cause the interacting effects of GW and OA on coral fertilization.

  3. Thermal processing of acidified foods with pH 4.1 to pH 4.6

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shelf-stable acidified foods with a pH at or below 4.6 must be processed to achieve a 5-log reduction for vegetative bacterial pathogens. Published research does not exist to adequately support the Food and Drug Administration process filings for products with pH 4.1–4.6 or to define critical limits...

  4. Preservation of acidified cucumbers with a combination of fumaric acid and cinnamaldehyde that target lactic acid bacteria and yeasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The naturally occurring compound, fumaric acid, was evaluated as a potential preservative for the long-term storage of cucumbers. Fumaric acid inhibited growth of lactic acid bacteria (LAB) in an acidified cucumber juice medium model system resembling conditions that could allow preservation of cucu...

  5. Determination of 5-log reduction times for food pathogens in acidified cucumbers during storage at 10 and 25 degrees C.

    PubMed

    Breidt, Fred; Hayes, Janet; McFeeters, Roger F

    2007-11-01

    Outbreaks of acid-resistant foodborne pathogens in acid foods with pH values below 4.0, including apple cider and orange juice, have raised concerns about the safety of acidified vegetable products. For acidified vegetable products with pH values between 3.3 and 4.6, previous research has demonstrated that thermal treatments are needed to achieve a 5-log reduction in the numbers of Escherichia coli O157:H7, Listeria monocytogenes, or Salmonella enterica. For some acidified vegetable products with a pH of 3.3 or below, heat processing can result in unacceptable product quality. The purpose of this study was to determine the holding times needed to achieve a 5-log reduction in E. coli O157:H7, L. monocytogenes, and S. enterica strains in acidified vegetable products with acetic acid as the primary acidulant, a pH of 3.3 or below, and a minimum equilibrated temperature of 10 degrees C. We found E. coli O157:H7 to be the most acid-resistant microorganism for the conditions tested, with a predicted time to achieve a 5-log reduction in cell numbers at 10 degrees C of 5.7 days, compared with 2.1 days (51 h) for Salmonella or 0.5 days (11.2 h) for Listeria. At 25 degrees C, the E. coli O157:H7 population achieved a 5-log reduction in 1.4 days (34.3 h).

  6. Trends in Surface Water Chemistry in Acidified Areas in Europe and North America from 1990 to 2008

    EPA Science Inventory

    Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analyzed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (...

  7. Growth inhibition of Cronobacter spp. strains in reconstituted powdered infant formula acidified with organic acids supported by natural stomach acidity.

    PubMed

    Zhu, S; Schnell, S; Fischer, M

    2013-09-01

    Cronobacter is associated with outbreaks of rare, but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in newborns. This study was conducted to determine the effect of organic acids on growth of Cronobacter in laboratory medium and reconstituted powdered infant formula (PIF) as well as the bacteriostatic effect of slightly acidified infant formula when combined with neonatal gastric acidity. Inhibitory effect of seven organic acids on four acid sensitive Cronobacter strains was determined in laboratory medium with broth dilution method at pH 5.0, 5.5 and 6.0. Acetic, butyric and propionic acids were most inhibitive against Cronobacter in the laboratory medium. The killing effect of these three acids was partially buffered in reconstituted PIF. Under neonatal gastric acid condition of pH 5.0, the slightly acidified formula which did not exert inhibition effect solely reduced significantly the Cronobacter populations. A synergistic effect of formula moderately acidified with organic acid combined with the physiological infant gastric acid was visible in preventing the rapid growth of Cronobacter in neonatal stomach. The study contributed to a better understanding of the inhibitory effect of organic acids on Cronobacter growth in different matrixes and provided new ideas in terms of controlling bacteria colonization and translocation by acidified formula.

  8. Biological Nitrogen Removal through Nitritation Coupled with Thiosulfate-Driven Denitritation

    NASA Astrophysics Data System (ADS)

    Qian, Jin; Zhou, Junmei; Zhang, Zhen; Liu, Rulong; Wang, Qilin

    2016-06-01

    A novel biological nitrogen removal system based on nitritation coupled with thiosulfate-driven denitritation (Nitritation-TDD) was developed to achieve a high nitrogen removal rate and low sludge production. A nitritation sequential batch reactor (nitritation SBR) and an anoxic up-flow sludge bed (AnUSB) reactor were applied for effective nitritation and denitritation, respectively. Above 75% nitrite was accumulated in the nitritation SBR with an influent ammonia loading rate of 0.43 kg N/d/m3. During Nitritation-TDD operation, particle sizes (d50) of the sludge decreased from 406 to 225 um in nitritation SBR and from 327–183 um in AnUSB reactor. Pyrosequencing tests revealed that ammonium-oxidizing bacteria (AOB) population was stabilized at approximately 7.0% (calculated as population of AOB-related genus divided by the total microbial population) in the nitritation SBR. In contrast, nitrite-oxidizing bacteria (NOB) population decreased from 6.5–0.6% over the same time, indicating the effective nitrite accumulation in the nitritation SBR. Thiobacillus, accounting for 34.2% in the AnUSB reactor, was mainly responsible for nitrogen removal via autotrophic denitritation, using an external source of thiosulfate as electron donor. Also, it was found that free nitrous acid could directly affect the denitritation activity.

  9. Measurement of nitrite in urine by gas chromatography-mass spectrometry.

    PubMed

    Tsikas, Dimitrios; Suchy, Maria-Theresia; Mitschke, Anja; Beckmann, Bibiana; Gutzki, Frank-Mathias

    2012-01-01

    Nitric oxide (NO) is enzymatically produced from L-arginine and has a variety of biological functions. Autoxidation of NO in aqueous media yields nitrite (O = N-O(-)). NO and nitrite are oxidized in erythrocytes by oxyhemoglobin to nitrate (NO(3)(-)). Nitrate reductases from bacteria reduce nitrate to nitrite. Nitrite and nitrate are ubiquitous in nature, they are present throughout the body and they are excreted in the urine. Nitrite in urine has been used for several decades as an indicator and measure of bacteriuria. Since the identification of nitrite as a metabolite of NO, circulating nitrite is also used as an indicator of NO synthesis and is considered an NO storage form. In contrast to plasma nitrite, the significance of nitrite in the urine beyond bacteriuria is poorly investigated and understood. This chapter describes a gas chromatography-mass spectrometry (GC-MS) protocol for the quantitative determination of nitrite in urine of humans. Although the method is useful for detection and quantification of bacteriuria, the procedures described herein are optimum for urinary nitrite in conditions other than urinary tract infection. The method uses [(15)N]nitrite as internal standard and pentafluorobenzyl bromide as the derivatization agent. Derivatization is -performed on 100-μL aliquots and quantification of toluene extracts by selected-ion monitoring of m/z 46 for urinary nitrite and m/z 47 for the internal standard in the electron-capture negative-ion chemical ionization mode.

  10. Biological Nitrogen Removal through Nitritation Coupled with Thiosulfate-Driven Denitritation

    PubMed Central

    Qian, Jin; Zhou, Junmei; Zhang, Zhen; Liu, Rulong; Wang, Qilin

    2016-01-01

    A novel biological nitrogen removal system based on nitritation coupled with thiosulfate-driven denitritation (Nitritation-TDD) was developed to achieve a high nitrogen removal rate and low sludge production. A nitritation sequential batch reactor (nitritation SBR) and an anoxic up-flow sludge bed (AnUSB) reactor were applied for effective nitritation and denitritation, respectively. Above 75% nitrite was accumulated in the nitritation SBR with an influent ammonia loading rate of 0.43 kg N/d/m3. During Nitritation-TDD operation, particle sizes (d50) of the sludge decreased from 406 to 225 um in nitritation SBR and from 327–183 um in AnUSB reactor. Pyrosequencing tests revealed that ammonium-oxidizing bacteria (AOB) population was stabilized at approximately 7.0% (calculated as population of AOB-related genus divided by the total microbial population) in the nitritation SBR. In contrast, nitrite-oxidizing bacteria (NOB) population decreased from 6.5–0.6% over the same time, indicating the effective nitrite accumulation in the nitritation SBR. Thiobacillus, accounting for 34.2% in the AnUSB reactor, was mainly responsible for nitrogen removal via autotrophic denitritation, using an external source of thiosulfate as electron donor. Also, it was found that free nitrous acid could directly affect the denitritation activity. PMID:27272192

  11. Physiology and interaction of nitrate and nitrite reduction in Staphylococcus carnosus.

    PubMed Central

    Neubauer, H; Götz, F

    1996-01-01

    Staphylococcus carnosus reduces nitrate to ammonia in two steps. (i) Nitrate was taken up and reduced to nitrite, and nitrite was subsequently excreted. (ii) After depletion of nitrate, the accumulated nitrite was imported and reduced to ammonia, which again accumulated in the medium. The localization, energy gain, and induction of the nitrate and nitrite reductases in S. carnosus were characterized. Nitrate reductase seems to be a membrane-bound enzyme involved in respiratory energy conservation, whereas nitrite reductase seems to be a cytosolic enzyme involved in NADH reoxidation. Syntheses of both enzymes are inhibited by oxygen and induced to greater or lesser degrees by nitrate or nitrite, respectively. In whole cells, nitrite reduction is inhibited by nitrate and also by high concentrations of nitrite (> or = 10 mM). Nitrite did not influence nitrate reduction. Two possible mechanisms for the inhibition of nitrite reduction by nitrate that are not mutually exclusive are discussed. (i) Competition for NADH nitrate reductase is expected to oxidize the bulk of the NADH because of its higher specific activity. (ii) The high rate of nitrate reduction could lead to an internal accumulation of nitrite, possibly the result of a less efficient nitrite reduction or export. So far, we have no evidence for the presence of other dissimilatory or assimilatory nitrate or nitrite reductases in S. carnosus. PMID:8606176

  12. Physiology and interaction of nitrate and nitrite reduction in Staphylococcus carnosus.

    PubMed

    Neubauer, H; Götz, F

    1996-04-01

    Staphylococcus carnosus reduces nitrate to ammonia in two steps. (i) Nitrate was taken up and reduced to nitrite, and nitrite was subsequently excreted. (ii) After depletion of nitrate, the accumulated nitrite was imported and reduced to ammonia, which again accumulated in the medium. The localization, energy gain, and induction of the nitrate and nitrite reductases in S. carnosus were characterized. Nitrate reductase seems to be a membrane-bound enzyme involved in respiratory energy conservation, whereas nitrite reductase seems to be a cytosolic enzyme involved in NADH reoxidation. Syntheses of both enzymes are inhibited by oxygen and induced to greater or lesser degrees by nitrate or nitrite, respectively. In whole cells, nitrite reduction is inhibited by nitrate and also by high concentrations of nitrite (> or = 10 mM). Nitrite did not influence nitrate reduction. Two possible mechanisms for the inhibition of nitrite reduction by nitrate that are not mutually exclusive are discussed. (i) Competition for NADH nitrate reductase is expected to oxidize the bulk of the NADH because of its higher specific activity. (ii) The high rate of nitrate reduction could lead to an internal accumulation of nitrite, possibly the result of a less efficient nitrite reduction or export. So far, we have no evidence for the presence of other dissimilatory or assimilatory nitrate or nitrite reductases in S. carnosus.

  13. High Sodium Simulant Testing To Support SB8 Sludge Preparation

    SciTech Connect

    Newell, J. D.

    2012-09-19

    Scoping studies were completed for high sodium simulant SRAT/SME cycles to determine any impact to CPC processing. Two SRAT/SME cycles were performed with simulant having sodium supernate concentration of 1.9M at 130% and 100% of the Koopman Minimum Acid requirement. Both of these failed to meet DWPF processing objectives related to nitrite destruction and hydrogen generation. Another set of SRAT/SME cycles were performed with simulant having a sodium supernate concentration of 1.6M at 130%, 125%, 110%, and 100% of the Koopman Minimum Acid requirement. Only the run at 110% met DWPF processing objectives. Neither simulant had a stoichiometric factor window of 30% between nitrite destruction and excessive hydrogen generation. Based on the 2M-110 results it was anticipated that the 2.5M stoichiometric window for processing would likely be smaller than from 110-130%, since it appeared that it would be necessary to increase the KMA factor by at least 10% above the minimum calculated requirement to achieve nitrite destruction due to the high oxalate content. The 2.5M-130 run exceeded the DWPF hydrogen limits in both the SRAT and SME cycle. Therefore, testing of this wash endpoint was halted. This wash endpoint with this minimum acid requirement and mercury-noble metal concentration profile appears to be something DWPF should not process due to an overly narrow window of stoichiometry. The 2M case was potentially processable in DWPF, but modifications would likely be needed in DWPF such as occasionally accepting SRAT batches with undestroyed nitrite for further acid addition and reprocessing, running near the bottom of the as yet ill-defined window of allowable stoichiometric factors, potentially extending the SRAT cycle to burn off unreacted formic acid before transferring to the SME cycle, and eliminating formic acid additions in the frit slurry.

  14. Proton affinity of methyl nitrite and methyl peroxynitrite: implications for measuring branching ratios of alkyl nitrates and nitrites.

    PubMed

    Ravelo, Rose M; Francisco, Joseph S

    2008-08-20

    Geometry optimizations for methyl nitrite and methyl peroxynitrite, along with various protonated isomers for each, have been investigated using ab initio and density functional methods. The lowest energy structure for protonated methyl nitrite is a complex between CH3OH and NO(+). For methyl peroxynitrite, the lowest energy protonated structure is a complex between CH3OOH and NO(+). Their respective proton affinities are estimated to be 195.2 and 195.8 kcal/mol at the QCISD(T)/6-311++G(3df,3pd) level of theory. The results, compared with past studies, suggest an alternative method for directly measuring branching ratios for production of alkyl nitrates and nitrites.

  15. The effect of nitrite on aerobic phosphate uptake and denitrifying activity of phosphate-accumulating organisms.

    PubMed

    Yoshida, Y; Takahashi, K; Saito, T; Tanaka, K

    2006-01-01

    An anaerobic/aerobic/anoxic/aerobic sequencing batch reactor (SBR) was operated with municipal wastewater to investigate the effect of nitrite on biological phosphorus removal (BPR). When nitrite accumulated, aerobic phosphate uptake activity significantly decreased and, in case of hard exposure to nitrite, BPR severely deteriorated. The interesting observation was that the relative anoxic activity of phosphate accumulating organisms (PAOs) increased after nitrite exposure. Moreover batch tests of aerobic phosphate uptake in the presence/absence of nitrite indicated that PAOs with the higher relative anoxic activity are less sensitive to nitrite exposure. From these results, we concluded that BPR is sensitive to nitrite exposure, but BPR containing PAOs with the higher relative anoxic activity is possibly more stable against nitrite than BPR containing PAOs with the lower relative anoxic activity.

  16. Pre-exposure to nitrite in the absence of ammonium strongly inhibits anammox.

    PubMed

    Carvajal-Arroyo, José M; Puyol, Daniel; Li, Guangbin; Lucero-Acuña, Armando; Sierra-Álvarez, Reyes; Field, Jim A

    2014-01-01

    Anaerobic ammonium oxidizing bacteria (Anammox) are known to be inhibited by their substrate, nitrite. However, the mechanism of inhibition and the physiological conditions under which nitrite impacts the performance of anammox bioreactors are still unknown. This study investigates the role of pre-exposing anammox bacteria to nitrite alone on their subsequent activity and metabolism after ammonium has been added. Batch experiments were carried out with anammox granular biofilm pre-exposed to nitrite over a range of concentrations and durations in the absence of ammonium. The effect of pre-exposure to nitrite alone compared to nitrite simultaneously fed with ammonium was evaluated by measuring the anammox activity and the accumulation of the intermediate, nitric oxide. The results show that the inhibitory effect was more dramatic when bacteria were pre-exposed to nitrite in absence of ammonium, as revealed by the lower activity and the higher accumulation of nitric oxide. The nitrite concentration causing 50% inhibition was 53 and 384 mg N L(-1) in the absence or the presence of ammonium, respectively. The nitrite inhibition was thus 7.2-fold more severe in the absence of ammonium. Biomass exposure to nitrite (25 mg N L(-1)), in absence of ammonium, led to accumulation of nitric oxide. On the other hand when the biomass was exposed to nitrite in presence of ammonium, accumulation of nitric oxide was only observed at much higher nitrite concentrations (500 mg N L(-1)). The inhibitory effect of nitrite in the absence of ammonium was very rapid. The rate of decay of the anammox activity was equivalent to the diffusion rate of nitrite up to 46% of activity loss. The results taken as a whole suggest that nitrite inhibition is more acute when anammox cells are not actively metabolizing. Accumulation of nitric oxide in the headspace most likely indicates disruption of the anammox biochemistry by nitrite inhibition, caused by an interruption of the hydrazine synthesis step.

  17. The existence and significance of a mitochondrial nitrite reductase.

    PubMed

    Nohl, Hans; Staniek, Katrin; Kozlov, Andrey V

    2005-01-01

    The physiological functions of nitric oxide (NO) are well established. The finding that the endothelium-derived relaxing factor (EDRF) is NO was totally unexpected. It was shown that NO is a reaction product of an enzymatically catalyzed, overall, 5-electron oxidation of guanidinium nitrogen from L-arginine followed by the release of the free radical species NO. NO is synthesized by a single protein complex supported by cofactors, coenzymes (such as tetrahydrobiopterin) and cytochrome P450. The latter can uncouple from substrate oxidation producing O2*- radicals. The research groups of Richter [Ghafourifar P, Richter C. Nitric oxide synthase activity in mitochondria. FEBS Lett 1997; 418: 291-296.] and Boveris [Giulivi C, Poderoso JJ, Boveris A. Production of nitric oxide by mitochondria. J Biol Chem 1998; 273: 11038-11043.] identified a mitochondrial NO synthase (NOS). There are, however, increasing reports demonstrating that mitochondrial NO is derived from cytosolic NOS belonging to the Ca2+-dependent enzymes. NO was thought to control cytochrome oxidase. This assumption is controversial due to the life-time of NO in biological systems (millisecond range). We found a nitrite reductase in mitochondria which is of major interest. Any increase of nitrite in the tissue which is the first oxidation product of NO, for instance following NO donors, will stimulate NO-recycling via mitochondrial nitrite reductase. In this paper, we describe the identity and the function of mitochondrial nitrite reductase and the consequences of NO-recycling in the metabolic compartment of mitochondria.

  18. Nitrate, Nitrite, and Ammonium Variability in Drinking Water Distribution Systems.

    PubMed

    Schullehner, Jörg; Stayner, Leslie; Hansen, Birgitte

    2017-03-09

    Accurate assessments of exposure to nitrate in drinking water is a crucial part of epidemiological studies investigating long-term adverse human health effects. However, since drinking water nitrate measurements are usually collected for regulatory purposes, assumptions on (1) the intra-distribution system variability and (2) short-term (seasonal) concentration variability have to be made. We assess concentration variability in the distribution system of nitrate, nitrite, and ammonium, and seasonal variability in all Danish public waterworks from 2007 to 2016. Nitrate concentrations at the exit of the waterworks are highly correlated with nitrate concentrations within the distribution net or at the consumers' taps, while nitrite and ammonium concentrations are generally lower within the net compared with the exit of the waterworks due to nitrification. However, nitrification of nitrite and ammonium in the distribution systems only results in a relatively small increase in nitrate concentrations. No seasonal variation for nitrate, nitrite, or ammonium was observed. We conclude that nitrate measurements taken at the exit of the waterworks are suitable to calculate exposures for all consumers connected to that waterworks and that sampling frequencies in the national monitoring programme are sufficient to describe temporal variations in longitudinal studies.

  19. Nitrite as an antidote for acute hydrogen sulfide intoxication

    SciTech Connect

    Beck, J.F.; Bradbury, C.M.; Connors, A.J.; Donini, J.C.

    1981-11-01

    The detoxification of hydrogen sulfide (H/sub 2/S) by a heme catalyzed oxidation was examined as part of an on-going study of H/sub 2/S toxicity. Interlocking O/sub 2/ absorption and sulfide depletion data indicate that both oxyhemoglobin and methemoglobin are effective catalytic agents. Although the latter is more efficacious, the life time of excess sulfide in the presence of oxygen and either of the above is of the order of minutes. It has also been established that the formation of methemoglobin following nitrite administration occurs preferentially under oxygen poor conditions. Under an atmospheric or oxygen enriched environment, which favors sulfide depletion, the nitrite retards sulfide oxidation. Thus nitrite as an antidote for acute H/sub 2/S intoxication can only be effective within the first few minutes after the exposure, at which time resuscitation and/or ventilation of the victim is likely to produce conditions in which the nitrite actually slows sulfide removal.

  20. Ammonia and nitrite oxidation in the Eastern Tropical North Pacific

    NASA Astrophysics Data System (ADS)

    Peng, Xuefeng; Fuchsman, Clara A.; Jayakumar, Amal; Oleynik, Sergey; Martens-Habbena, Willm; Devol, Allan H.; Ward, Bess B.

    2015-12-01

    Nitrification plays a key role in the marine nitrogen (N) cycle, including in oceanic oxygen minimum zones (OMZs), which are hot spots for denitrification and anaerobic ammonia oxidation (anammox). Recent evidence suggests that nitrification links the source (remineralized organic matter) and sink (denitrification and anammox) of fixed N directly in the steep oxycline in the OMZs. We performed shipboard incubations with 15N tracers to characterize the depth distribution of nitrification in the Eastern Tropical North Pacific (ETNP). Additional experiments were conducted to investigate photoinhibition. Allylthiourea (ATU) was used to distinguish the contribution of archaeal and bacterial ammonia oxidation. The abundance of archaeal and β-proteobacterial ammonia monooxygenase gene subunit A (amoA) was determined by quantitative polymerase chain reaction. The rates of ammonia and nitrite oxidation showed distinct subsurface maxima, with the latter slightly deeper than the former. The ammonia oxidation maximum coincided with the primary nitrite concentration maximum, archaeal amoA gene maximum, and the subsurface nitrous oxide maximum. Negligible rates of ammonia oxidation were found at anoxic depths, where high rates of nitrite oxidation were measured. Archaeal amoA gene abundance was generally 1 to 2 orders of magnitude higher than bacterial amoA gene abundance, and inhibition of ammonia-oxidizing bacteria with 10 μM ATU did not affect ammonia oxidation rates, indicating the dominance of archaea in ammonia oxidation. These results depict highly dynamic activities of ammonia and nitrite oxidation in the oxycline of the ETNP OMZ.

  1. Evaluation of nitrate and nitrite destruction/separation technologies

    SciTech Connect

    Hobbs, D.T.

    1997-08-29

    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.

  2. Nitrate metabolism in tobacco leaves overexpressing Arabidopsis nitrite reductase.

    PubMed

    Davenport, Susie; Le Lay, Pascaline; Sanchez-Tamburrrino, Juan Pablo

    2015-12-01

    Primary nitrogen assimilation in plants includes the reduction of nitrite to ammonium in the chloroplasts by the enzyme nitrite reductase (NiR EC:1.7.7.1) or in the plastids of non-photosynthetic organs. Here we report on a study overexpressing the Arabidopsis thaliana NiR (AtNiR) gene in tobacco plants under the control of a constitutive promoter (CERV - Carnation Etched Ring Virus). The aim was to overexpress AtNiR in an attempt to alter the level of residual nitrite in the leaf which can act as precursor to the formation of nitrosamines. The impact of increasing the activity of AtNiR produced an increase in leaf protein and a stay-green phenotype in the primary transformed AtNiR population. Investigation of the T1 homozygous population demonstrated elevated nitrate reductase (NR) activity, reductions in leaf nitrite and nitrate and the amino acids proline, glutamine and glutamate. Chlorophyl content of the transgenic lines was increased, as evidenced by the stay-green phenotype. This reveals the importance of NiR in primary nitrogen assimilation and how modification of this key enzyme affects both the nitrogen and carbon metabolism of tobacco plants.

  3. Nitrate, Nitrite, and Ammonium Variability in Drinking Water Distribution Systems

    PubMed Central

    Schullehner, Jörg; Stayner, Leslie; Hansen, Birgitte

    2017-01-01

    Accurate assessments of exposure to nitrate in drinking water is a crucial part of epidemiological studies investigating long-term adverse human health effects. However, since drinking water nitrate measurements are usually collected for regulatory purposes, assumptions on (1) the intra-distribution system variability and (2) short-term (seasonal) concentration variability have to be made. We assess concentration variability in the distribution system of nitrate, nitrite, and ammonium, and seasonal variability in all Danish public waterworks from 2007 to 2016. Nitrate concentrations at the exit of the waterworks are highly correlated with nitrate concentrations within the distribution net or at the consumers’ taps, while nitrite and ammonium concentrations are generally lower within the net compared with the exit of the waterworks due to nitrification. However, nitrification of nitrite and ammonium in the distribution systems only results in a relatively small increase in nitrate concentrations. No seasonal variation for nitrate, nitrite, or ammonium was observed. We conclude that nitrate measurements taken at the exit of the waterworks are suitable to calculate exposures for all consumers connected to that waterworks and that sampling frequencies in the national monitoring programme are sufficient to describe temporal variations in longitudinal studies. PMID:28282914

  4. Nitrite/nitrate and malondialdehyde levels in nasal polyp.

    PubMed

    Bugdayci, G; Kaymakci, M

    2008-10-28

    The aim of this study was to examine the pathophysiological role of NO (nitric oxide) and MDA (malondialdehyde) in tissue in patients with nasal polyposis. We measured nitrite/nitrate (Nitrite/Nitrate; NO2-/NO3-) and MDA in tissue and plasma of NP patients (n=20) and controls (n=20). MDA level expressed as the concentration of substances reacting to thiobarbituric acid and production of NO (concentration of nitrite/nitrate in plasma) by the Griess reaction were determined. The level of NO2- and NO3- in tissue are higher than that of the normal tissue (p<0.05). The level of MDA in tissue are higher than that of the normal tissue (p<0.05). The level of NO2- and NO3- in plasma of two groups are similar (p>0.05). The level of MDA in plasma is higher than that in the normal controls (p<0.05). The change in NO2-/NO3- and MDA levels of nasal polyp patients was demonstrated. Further studies are required concerning the significance of changes in lipid peroxidation and nitrite levels in pathogenesis of nasal polyp.

  5. Neurotoxicity induced by alkyl nitrites: Impairment in learning/memory and motor coordination.

    PubMed

    Cha, Hye Jin; Kim, Yun Ji; Jeon, Seo Young; Kim, Young-Hoon; Shin, Jisoon; Yun, Jaesuk; Han, Kyoungmoon; Park, Hye-Kyung; Kim, Hyung Soo

    2016-04-21

    Although alkyl nitrites are used as recreational drugs, there is only little research data regarding their effects on the central nervous system including their neurotoxicity. This study investigated the neurotoxicity of three representative alkyl nitrites (isobutyl nitrite, isoamyl nitrite, and butyl nitrite), and whether it affected learning/memory function and motor coordination in rodents. Morris water maze test was performed in mice after administrating the mice with varying doses of the substances in two different injection schedules of memory acquisition and memory retention. A rota-rod test was then performed in rats. All tested alkyl nitrites lowered the rodents' capacity for learning and memory, as assessed by both the acquisition and retention tests. The results of the rota-rod test showed that isobutyl nitrite in particular impaired motor coordination in chronically treated rats. The mice chronically injected with isoamyl nitrite also showed impaired function, while butyl nitrite had no significant effect. The results of the water maze test suggest that alkyl nitrites may impair learning and memory. Additionally, isoamyl nitrite affected the rodents' motor coordination ability. Collectively, our findings suggest that alkyl nitrites may induce neurotoxicity, especially on the aspect of learning and memory function.

  6. 21 CFR 250.100 - Amyl nitrite inhalant as a prescription drug for human use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Amyl nitrite inhalant as a prescription drug for... Prescription Status of Specific Drugs § 250.100 Amyl nitrite inhalant as a prescription drug for human use. (a) Amyl nitrite inhalant has been available over-the-counter for emergency use by the patient in...

  7. 21 CFR 250.100 - Amyl nitrite inhalant as a prescription drug for human use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Amyl nitrite inhalant as a prescription drug for... Prescription Status of Specific Drugs § 250.100 Amyl nitrite inhalant as a prescription drug for human use. (a) Amyl nitrite inhalant has been available over-the-counter for emergency use by the patient in...

  8. 75 FR 29534 - Inorganic Nitrates-Nitrite, Carbon and Carbon Dioxide, and Sulfur Registration Review; Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ... Nitrates-Nitrite, Carbon and Carbon Dioxide, and Sulfur Registration Review; Draft Ecological Risk... ecological risk assessment for the registration review of inorganic nitrates - nitrites, carbon and carbon... inorganic nitrates- nitrites, carbon and carbon dioxide uses, as well as gas cartridge uses of sulfur....

  9. Influence of sodium nitrite on protein oxidation and nitrosation of sausages subjected to processing and storage.

    PubMed

    Feng, Xianchao; Li, Chenyi; Jia, Xu; Guo, Yan; Lei, Na; Hackman, Robert M; Chen, Lin; Zhou, Guanghong

    2016-06-01

    The influence of NaNO2 content on protein oxidation and nitrosation was investigated in cooked sausages at different concentrations (0, 50, 100, 200 and 400 mg NaNO2/kg). Dependent on concentration, NaNO2 had both anti- and pro-oxidant effects on protein oxidation. The antioxidant effects of NaNO2 on the protein oxidation were evidenced by significantly lower carbonyl contents, higher free amines and lower surface hydrophobicities. The pro-oxidant effects of NaNO2 on protein oxidation resulted in a decrease of sulfhydryls and an increase of disulfide bonds. NaNO2 also improved the protein nitrosation inducing the formation of 3-nitrotyrosine (3-NT). Moreover, 3-NT had significant correlations with parameters of protein oxidation, indicating that 3-NT may be a possible marker for protein oxidation. Results of this study contribute to an understanding of the impact of NaNO2 on food quality and help to identify optimal formulations of cured meat products.

  10. 21 CFR 172.177 - Sodium nitrite used in processing smoked chub.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 38 °F or below shall be maintained during all subsequent storage and distribution. All shipping... nature of the product and specify that the product shall be held under refrigeration (38 °F or...

  11. 21 CFR 172.177 - Sodium nitrite used in processing smoked chub.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... subsequent storage and distribution. All shipping containers, retail packages, and shipping records shall... held under refrigeration (38 °F or below) until consumed. (e) To assure safe use of the additive:...

  12. 21 CFR 172.177 - Sodium nitrite used in processing smoked chub.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... subsequent storage and distribution. All shipping containers, retail packages, and shipping records shall... held under refrigeration (38 °F or below) until consumed. (e) To assure safe use of the additive:...

  13. Nutrient digestibility and mass balance in laying hens fed a commercial or acidifying diet.

    PubMed

    Wu-Haan, W; Powers, W J; Angel, C R; Hale, C E; Applegate, T J

    2007-04-01

    The objectives of the current study were to evaluate the effect of an acidifying diet (gypsum) combined with zeolite and slightly reduced crude protein (R) vs. a control diet (C) on nutrient retention in laying hens and compare 3 approaches to estimating nutrient excretion from hens: 1) mass balance calculation (feed nutrients - egg nutrient), 2) use of an indigestible marker with analyzed feed and excreta nutrient content, and 3) an environmental chamber that allowed for capturing all excreted and volatilized nutrients. Hens (n = 640) were allocated randomly to 8 environmental chambers for 3-wk periods. Excreta samples were collected at the end of each trial to estimate apparent retention of N, S, P, and Ca. No diet effects on apparent retention of N were observed (53.44%, P > 0.05). Apparent retention of S, P, and Ca decreased in hens fed R diet (18.7, - 11.4, and 22.6%, respectively) compared with hens fed the C diet (40.7, 0.3, and 28.6%, respectively; P < 0.05). Total N excretion from hens fed the C and R diet was not different (1.16 g/hen/d); however, mass of chamber N remaining in excreta following the 3-wk period was less from hens fed the C diet (1.27 kg) than from hens fed the R diet (1.43 kg). Gaseous emissions of NH(3) over the 3-wk period from hens fed the C diet (0.74 kg per chamber) were greater than emissions from hens fed the R diet (0.45 kg). The 3-wk S excretion mass (estimated using the calculation, indigestible marker, and environmental chamber methods, respectively) was greater from hens fed the R diet (1.85, 1.54, and 1.27 kg, respectively) compared with hens fed the C diet (0.24, 0.20, and 0.14 kg, respectively). The 3-wk P excretion was similar between diets (0.68 kg). Results demonstrate that feeding the acidified diet resulted in decreased N emissions, but because of the acidulant fed, greatly increased S excretion and emissions.

  14. Sequestration of organic cations by acidified hepatic endocytic vesicles and implications for biliary excretion.

    PubMed

    Van Dyke, R W; Faber, E D; Meijer, D K

    1992-04-01

    A number of cationic amine drugs that are taken up by liver and excreted into bile may accumulate in acidified intracellular organelles such as lysosomes and endosomes. These studies were undertaken to assess directly the uptake and accumulation of three types of model organic cationic amines by endocytic vesicles, and the role of vesicle acidification in this process. Uptake of tubocurarine (TC), vecuronium and tributylmethylammonium (TBuMA) by purified rat liver multivesicular bodies (MVB) (prelysosomal endocytic vesicles) was dependent upon MgATP, time and drug concentration. After 60 min, 52 to 81% of MVB cation content was dependent upon vesicle acidification (due to an electrogenic proton pump), but not upon an interior positive vesicle membrane potential. Nineteen to 42% of MVB cation content appeared due to binding to MVB membranes or to internal lipoproteins. Vesicle-to-medium ATP-dependent apparent concentration ratios for these three cations were 3.3 to 51. MVB uptake of these cations resembled uptake of methylamine, a tertiary amine known to distribute across organellar membranes according to pH gradients. By contrast, MVB uptake of the lipophilic quaternary amine methyldeptropine was not dependent upon MgATP or on development of MVB pH or membrane potential gradients. In further studies, TC, vecuronium and TBuMA were rapidly taken up by the isolated perfused rat liver and excreted in bile. Exposure to 250 mciroM primaquin (which partially alkalinized acidic endosomes and lysosomes) reduced accumulation of [3H]vecuronium in a lysosomal fraction by 23%, decreased perfusate disappearance of TC and TBuMA, but not of vecuronium, and decreased biliary appearance of all three cations. These studies suggest that acidified intracellular organelles sequester certain organic cationic drugs, possibly via a drug/proton antiporter, and/or diffusion followed by intravesicular protonation and trapping of tertiary amines. However, attempts at partial displacement of

  15. Organic tank safety project: Preliminary results of energetics and thermal behavior studies of model organic nitrate and/or nitrite mixtures and a simulated organic waste

    SciTech Connect

    Scheele, R.D.; Sell, R.L.; Sobolik, J.L.; Burger, L.L.

    1995-08-01

    As a result of years of production and recovery of nuclear defense materials and subsequent waste management at the Hanford Site, organic-bearing radioactive high-level wastes (HLW) are currently stored in large (up to 3. ML) single-shell storage tanks (SSTs). Because these wastes contain both fuels (organics) and the oxidants nitrate and nitrite, rapid energetic reactions at certain conditions could occur. In support of Westinghouse Hanford Company`s (WHC) efforts to ensure continued safe storage of these organic- and oxidant-bearing wastes and to define the conditions necessary for reactions to occur, we measured the thermal sensitivities and thermochemical and thermokinetic properties of mixtures of selected organics and sodium nitrate and/or nitrite and a simulated Hanford organic-bearing waste using thermoanalytical technologies. These thermoanalytical technologies are used by chemical reactivity hazards evaluation organizations within the chemical industry to assess chemical reaction hazards.

  16. Isoelectrophoretic characterization of Pseudomonas cytochrome oxidase/nitrite reductase and its heme d1-containing domain.

    PubMed

    Hull, H H; Wharton, D C

    1993-02-15

    The cytochrome oxidase/nitrite reductase of Pseudomonas aeruginosa has been purified to homogeneity as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When this "homogeneous" protein is subjected to electrophoretic titration curve analysis in ampholines or to isoelectric focusing in immobilized pH gradient gels it is resolved into several bands, each of which possesses the olive-green color of the holoenzyme. Although the patterns of resolution replicate for a given enzyme preparation differences occur among different preparations. Furthermore, storage for several months at -20 degrees C leads to an increase in the number of isoelectrophoretic forms. All preparations, however, have two primary bands, one with a pI of 6.97 and the other of 7.02. Both these bands possess significant cytochrome oxidase activity after elution from the gels. When each of the primary bands is eluted and again subjected to isoelectric focusing under the same conditions as before, each band interconverts into two bands with pIs of 6.97 and 7.02. The addition of the ligand cyanide to the holoenzyme produces a shift in the pI of the two bands to pIs 7.04 and 7.12 while the addition of nitrite shifts some of the band at pI 6.97 into that at pI 7.02. The heme d1-containing dipeptide of the enzyme, produced by treatment with subtilisin, also exhibits considerable heterogeneity upon electrophoretic titration curve analysis and by isoelectric focusing in immobiline gels. Possible explanations for the observed isoelectrophoretic behavior in terms of protein conformation and heme chemistry are discussed.

  17. Sodium and Food Sources

    MedlinePlus

    ... Disease Cholesterol High Blood Pressure Million Hearts® WISEWOMAN Sodium and Food Sources Recommend on Facebook Tweet Share ... food [PDF-867K] and how to reduce sodium. Sodium Reduction Is Challenging Types of food matter: More ...

  18. The natural rehabilitation of an anthropogenically acidified tropical Lake: two decades of monitoring.

    PubMed

    Araújo, Cristiano V M; Cohin-de-Pinho, Salomão J; Chastinet, Carla B A; Machado, Sandro L; da Silva, Eduardo M

    2013-01-01

    The rehabilitation of a pond after approximately 20 years of strong acidified conditions due to industrial and domestic waste deposition in its catchment basin is reviewed. We describe in this study the acidification process that occurred in a tropical pond in Northeast Brazil (Dunas Lake), the rehabilitation plan for the pond and the subsequent monitoring conducted over two decades. After the contamination assessment by the late 80s, a rehabilitation plan was carried out in the early 90s, in which the contaminated soil and water have been removed and reduced, respectively. No further attempt to neutralize the water or any remediation has been carried out. A toxicity monitoring plan based on toxicity assays with the fish Poecilia reticulata was employed to verify the natural rehabilitation of the pond. The data on toxicity, pH, conductivity, sulphate and dissolved iron recorded from 1994 to 2010 were also compiled and discussed. The collected data in 2003 and 2004 indicated changes in water quality and from them complementary management actions, namely improvement in the containment plant, were conducted in 2005. Results for toxicity assays and pH results indicated interannual changes in the water quality similar to rainy-dry periods. Moving average approach using pH data clearly showed the recovery process of Dunas Lake as well as the importance of the containment plan to reduce the contamination. Finally, a summary of the recent situation after two decades of rehabilitation is provided.

  19. Rheology and stability of acidified food emulsions treated with high pressure.

    PubMed

    Arora, Akshay; Chism, Grady W; Shellhammer, Thomas H

    2003-04-23

    The stability and rheology of acidified model oil-in-water emulsions (pH 3.6 +/- 0.1) were evaluated before and after high-pressure treatments. Varying concentrations of canola oil (0-50% w/w), whey protein isolate, polysorbate 60, soy lecithin (0.1-1.5% w/w each), and xanthan (0.0-0.2% w/w) were chosen. Exposure to high pressures (up to 800 MPa for 5 min at 30 degrees C) did not significantly affect the equivalent surface mean diameter D[3,2], flow behavior, and viscoelasticity of the whey protein isolate and polysorbate 60-stabilized emulsions. Pressure treatments had negligible effects on emulsion stability in these systems, except when xanthan (0.2% w/w) was present in which pressure improved the stability of polysorbate 60-stabilized emulsions. Soy lecithin-stabilized emulsions had larger mean particles sizes and lower emulsion volume indices than the others, indicating potential instability, and application of pressure further destabilized these emulsions.

  20. Transplanted aquatic mosses for monitoring trace metal mobilization in acidified streams of the Vosges Mountains, France

    SciTech Connect

    Mersch, J.; Guerold, F.; Rousselle, P.; Pihan, J.C. )

    1993-08-01

    As a result of acid depositions, trace metals are mobilized from the soils to the aquatic environment. Especially in poorly mineralized waters, elevated metal concentrations may rapidly have adverse effects on aquatic organisms. In particular, it has been shown that aluminium, a key element in the acidification process, is a toxic cofactor for fish and other biota. An accurate assessment of this specific form of water pollution may not be possible when only based on analyses of single water samples. On the one hand, water metal concentrations are often close to the detection limit of usual analytical techniques, and on the other hand, levels in acidified streams undergo strong temporal variations caused by acid pulses following meteorological events such as heavy rainfall and snowmelt. Compared to water analyses, indirect monitoring methods provide undeniable advantages for assessing water contamination. Aquatic bryophytes, in particular, have been regarded as interesting indicator organisms for trace metal pollution. However, their use has mainly been restricted to the lower course of streams for evaluating the impact of industrial discharges. The purpose of this study was to test the suitability of transplanted aquatic mosses for monitoring aluminium and four other trace metals (copper, iron, lead and zinc) in the particular context of acidifed streams draining a forested headwater catchment. 15 refs., 2 figs., 2 tabs.

  1. Experiments and modeling of variably permeable carbonate reservoir samples in contact with CO₂-acidified brines

    SciTech Connect

    Smith, Megan M.; Hao, Yue; Mason, Harris E.; Carroll, Susan A.

    2014-12-31

    Reactive experiments were performed to expose sample cores from the Arbuckle carbonate reservoir to CO₂-acidified brine under reservoir temperature and pressure conditions. The samples consisted of dolomite with varying quantities of calcite and silica/chert. The timescales of monitored pressure decline across each sample in response to CO₂ exposure, as well as the amount of and nature of dissolution features, varied widely among these three experiments. For all samples cores, the experimentally measured initial permeability was at least one order of magnitude or more lower than the values estimated from downhole methods. Nondestructive X-ray computed tomography (XRCT) imaging revealed dissolution features including “wormholes,” removal of fracture-filling crystals, and widening of pre-existing pore spaces. In the injection zone sample, multiple fractures may have contributed to the high initial permeability of this core and restricted the distribution of CO₂-induced mineral dissolution. In contrast, the pre-existing porosity of the baffle zone sample was much lower and less connected, leading to a lower initial permeability and contributing to the development of a single dissolution channel. While calcite may make up only a small percentage of the overall sample composition, its location and the effects of its dissolution have an outsized effect on permeability responses to CO₂ exposure. The XRCT data presented here are informative for building the model domain for numerical simulations of these experiments but require calibration by higher resolution means to confidently evaluate different porosity-permeability relationships.

  2. The behavior of rare earth elements in naturally and anthropogenically acidified waters

    USGS Publications Warehouse

    Wood, Scott A.; Gammons, Christopher H.; Parker, Stephen R.

    2006-01-01

    In this paper, the behavior of rare earth elements (REE) in a watershed impacted by acid-mine drainage (Fisher Creek, Montana) is compared to that in a volcanically acidified watershed (Rio Agrio and Lake Caviahue, Argentina). The REE behave conservatively in acidic waters with pH values less than approximately 5.5. However, above pH 5.5, REE concentrations are controlled by adsorption onto or co-precipitation with a variety of Fe or Al oxyhydroxides. The heavy REE partition to a greater extent into the solid phase than the light REE as pH rises above 6. Concentrations of REE exhibit diel (24-h) cycling in waters that were initially acidic, but have become neutralized downstream. In Fisher Creek, at the most downstream sampling station investigated (pH 6.8), concentrations of dissolved REE were 190–840% higher in the early morning versus the late afternoon. This cycling can be related to temperature-dependent, cyclic adsorption–desorption of REE onto hydrous ferric or aluminum oxide or both. Similar but gentler diel cycling of the REE was found at Rio Agrio. The existence of such cycling has important ramifications for the study of REE in natural waters.

  3. Trichodesmium’s strategies to alleviate phosphorus limitation in the future acidified oceans.

    PubMed

    Spungin, Dina; Berman-Frank, Ilana; Levitan, Orly

    2014-06-01

    Global warming may exacerbate inorganic nutrient limitation, including phosphorus (P), in the surface waters of tropical oceans that are home to extensive blooms of the marine diazotrophic cyanobacterium, Trichodesmium. We examined the combined effects of P limitation and pCO(2), forecast under ocean acidification scenarios, on Trichodesmium erythraeum IMS101 cultures. We measured nitrogen acquisition,glutamine synthetase activity, C uptake rates, intracellular Adenosine Triphosphate (ATP) concentration and the pool sizes of related key proteins. Here, we present data supporting the idea that cellular energy re-allocation enables the higher growth and N(2) fixation rates detected in Trichodesmium cultured under high pCO(2). This is reflected in altered protein abundance and metabolic pools. Also modified are particulate organic carbon and nitrogen production rates,enzymatic activities, and cellular ATP concentrations. We suggest that adjusting these cellular pathways to changing environmental conditions enables Trichodesmium to compensate for low P availability and to thrive in acidified oceans. Moreover, elevated pCO(2) could provide Trichodesmium with a competitive dominance that would extend its niche, particularly in P-limited regions of the tropical and subtropical oceans.

  4. Alterations of Fractures in Carbonate Rocks by CO2-Acidified Brines.

    PubMed

    Deng, Hang; Fitts, Jeffrey P; Crandall, Dustin; McIntyre, Dustin; Peters, Catherine A

    2015-08-18

    Fractures in geological formations may enable migration of environmentally relevant fluids, as in leakage of CO2 through caprocks in geologic carbon sequestration. We investigated geochemically induced alterations of fracture geometry in Indiana Limestone specimens. Experiments were the first of their kind, with periodic high-resolution imaging using X-ray computed tomography (xCT) scanning while maintaining high pore pressure (100 bar). We studied two CO2-acidified brines having the same pH (3.3) and comparable thermodynamic disequilibrium but different equilibrated pressures of CO2 (PCO2 values of 12 and 77 bar). High-PCO2 brine has a faster calcite dissolution kinetic rate because of the accelerating effect of carbonic acid. Contrary to expectations, dissolution extents were comparable in the two experiments. However, progressive xCT images revealed extensive channelization for high PCO2, explained by strong positive feedback between ongoing flow and reaction. The pronounced channel increasingly directed flow to a small region of the fracture, which explains why the overall dissolution was lower than expected. Despite this, flow simulations revealed large increases in permeability in the high-PCO2 experiment. This study shows that the permeability evolution of dissolving fractures will be larger for faster-reacting fluids. The overall mechanism is not because more rock dissolves, as would be commonly assumed, but because of accelerated fracture channelization.

  5. Elevated aluminium concentration in acidified headwater streams lowers aquatic hyphomycete diversity and impairs leaf-litter breakdown.

    PubMed

    Baudoin, J M; Guérold, F; Felten, V; Chauvet, E; Wagner, P; Rousselle, P

    2008-08-01

    Aquatic hyphomycetes play an essential role in the decomposition of allochthonous organic matter which is a fundamental process driving the functioning of forested headwater streams. We studied the effect of anthropogenic acidification on aquatic hyphomycetes associated with decaying leaves of Fagus sylvatica in six forested headwater streams (pH range, 4.3-7.1). Non-metric multidimensional scaling revealed marked differences in aquatic hyphomycete assemblages between acidified and reference streams. We found strong relationships between aquatic hyphomycete richness and mean Al concentration (r = -0.998, p < 0.0001) and mean pH (r = 0.962, p < 0.002), meaning that fungal diversity was severely depleted in acidified streams. By contrast, mean fungal biomass was not related to acidity. Leaf breakdown rate was drastically reduced under acidic conditions raising the issue of whether the functioning of headwater ecosystems could be impaired by a loss of aquatic hyphomycete species.

  6. Complex responses of intertidal molluscan embryos to a warming and acidifying ocean in the presence of UV radiation.

    PubMed

    Davis, Andrew R; Coleman, Daniel; Broad, Allison; Byrne, Maria; Dworjanyn, Symon A; Przeslawski, Rachel

    2013-01-01

    Climate change and ocean acidification will expose marine organisms to synchronous multiple stressors, with early life stages being potentially most vulnerable to changing environmental conditions. We simultaneously exposed encapsulated molluscan embryos to three abiotic stressors-acidified conditions, elevated temperate, and solar UV radiation in large outdoor water tables in a multifactorial design. Solar UV radiation was modified with plastic filters, while levels of the other factors reflected IPCC predictions for near-future change. We quantified mortality and the rate of embryonic development for a mid-shore littorinid, Bembicium nanum, and low-shore opisthobranch, Dolabrifera brazieri. Outcomes were consistent for these model species with embryos faring significantly better at 26°C than 22°C. Mortality sharply increased at the lowest temperature (22°C) and lowest pH (7.6) examined, producing a significant interaction. Under these conditions mortality approached 100% for each species, representing a 2- to 4-fold increase in mortality relative to warm (26°C) non-acidified conditions. Predictably, development was more rapid at the highest temperature but this again interacted with acidified conditions. Development was slowed under acidified conditions at the lowest temperature. The presence of UV radiation had minimal impact on the outcomes, only slowing development for the littorinid and not interacting with the other factors. Our findings suggest that a warming ocean, at least to a threshold, may compensate for the effects of decreasing pH for some species. It also appears that stressors will interact in complex and unpredictable ways in a changing climate.

  7. Evaluation of an experimental sodium chlorate product, with and without nitroethane, on Salmonella in cull dairy cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ruminant animals are natural reservoirs for Salmonella. These bacteria can reduce nitrate to nitrite through the membrane bound enzyme nitrate reductase which also has the ability to reduce chlorate to the cytotoxic end-product chlorite. An experimental product containing sodium chlorate (ECP) has...

  8. Renal carbonic anhydrases are involved in the reabsorption of endogenous nitrite.

    PubMed

    Chobanyan-Jürgens, Kristine; Schwarz, Alexandra; Böhmer, Anke; Beckmann, Bibiana; Gutzki, Frank-Mathias; Michaelsen, Jan T; Stichtenoth, Dirk O; Tsikas, Dimitrios

    2012-02-15

    Nitrite (ONO(-)) exerts nitric oxide (NO)-related biological actions and its concentration in the circulation may be of particular importance. Nitrite is excreted in the urine. Hence, the kidney may play an important role in nitrite/NO homeostasis in the vasculature. We investigated a possible involvement of renal carbonic anhydrases (CAs) in endogenous nitrite reabsorption in the proximal tubule. The potent CA inhibitor acetazolamide was administered orally to six healthy volunteers (5 mg/kg) and nitrite was measured in spot urine samples before and after administration. Acetazolamide increased abruptly nitrite excretion in the urine, strongly suggesting that renal CAs are involved in nitrite reabsorption in healthy humans. Additional in vitro experiments support our hypothesis that nitrite reacts with CO(2), analogous to the reaction of peroxynitrite (ONOO(-)) with CO(2), to form acid-labile nitrito carbonate [ONOC(O)O(-)]. We assume that this reaction is catalyzed by CAs and that nitrito carbonate represents the nitrite form that is actively transported into the kidney. The significance of nitrite reabsorption in the kidney and the underlying mechanisms, notably a direct involvement of CAs in the reaction between nitrite and CO(2), remain to be elucidated.

  9. Retention and leaching of nitrite by municipal solid waste incinerator bottom ash under the landfill circumstance.

    PubMed

    Yao, Jun; Kong, Qingna; Zhu, Huayue; Long, Yuyang; Shen, Dongsheng

    2015-01-01

    The retention and leaching of nitrite by municipal solid waste incinerator (MSWI) bottom ash could affect its migration in the landfill. In this study, the effect of the dosage of MSWI bottom ash as well as the variation of the landfill environmental parameters including pH, anions and organic matter on the nitrite retention and leaching behavior was investigated by batch experiments. The highest removal percentage (73.0%) of nitrite was observed when the dosage of MSWI bottom ash was 10 g L(-1) in 2 mg L(-1) nitrite solution. Further increase of the dosage would retard the retention, as the nitrite leaching from MSWI bottom ash was enhanced. The optimum retention of nitrite was observed when the pH was 5.0, while the leaching of nitrite showed a consistent reduction with the increase of pH. Besides, the presence of Cl(-), SO4(2)(-) and acetic acid could enhance the leaching of nitrite and mitigate the retention process. However, the retention of nitrite was enhanced by PO4(3)(-), which was probably due to the formation of the apatite, an active material for the adsorption of the nitrite. These results suggested that MSWI bottom ash could affect the migration of nitrite in the landfill, which was related to the variation of the landfill circumstance.

  10. The Effect of Low Osmotic Potential on Nitrite Reduction in Intact Spinach Chloroplasts 1

    PubMed Central

    Behrens, Paul W.; Xu, Fujuan; Werner, Marisa; Hoffman, Teresa; Marsho, Thomas V.; MacKay, A. Bryan

    1985-01-01

    The effect of water stress (reduced osmotic potential) on photosynthetic nitrite reduction was investigated using intact, isolated spinach (Spinacia oleracea) chloroplasts. Nitrite-dependent O2 evolution was inhibited 39% at −29.5 bars osmotic potential, relative to a control at −11 bars. In the presence of an uncoupler of photophosphorylation this inhibition was not seen. Reduced osmotic potential did not inhibit either methyl viologen reduction or photosynthetic O2 reduction. These results indicate that an inhibition of electron transport to ferredoxin cannot account for the observed inhibition of nitrite-dependent O2 evolution. In vitro assay of nitrite reductase activity showed that the interaction of the enzyme with nitrite was not affected by changes in the concentrations of ions or molecules that might be caused by water stress conditions. These results indicate that the most likely site for the effect of water stress on chloroplastic nitrite reduction is the interaction of ferredoxin with nitrite reductase. PMID:16664429

  11. Role of nitrate and nitrite in the induction of nitrite reductase in leaves of barley seedlings

    NASA Technical Reports Server (NTRS)

    Aslam, M.; Huffaker, R. C.

    1989-01-01

    The role of NO3- and NO2- in the induction of nitrite reductase (NiR) activity in detached leaves of 8-day-old barley (Hordeum vulgare L.) seedlings was investigated. Barley leaves contained 6 to 8 micromoles NO2-/gram fresh weight x hour of endogenous NiR activity when grown in N-free solutions. Supply of both NO2- and NO3- induced the enzyme activity above the endogenous levels (5 and 10 times, respectively at 10 millimolar NO2- and NO3- over a 24 hour period). In NO3(-)-supplied leaves, NiR induction occurred at an ambient NO3- concentration of as low as 0.05 millimolar; however, no NiR induction was found in leaves supplied with NO2- until the ambient NO2- concentration was 0.5 millimolar. Nitrate accumulated in NO2(-)-fed leaves. The amount of NO3- accumulating in NO2(-)-fed leaves induced similar levels of NiR as did equivalent amounts of NO3- accumulating in NO3(-)-fed leaves. Induction of NiR in NO2(-)-fed leaves was not seen until NO3- was detectable (30 nanomoles/gram fresh weight) in the leaves. The internal concentrations of NO3-, irrespective of N source, were highly correlated with the levels of NiR induced. When the reduction of NO3- to NO2- was inhibited by WO4(2-), the induction of NiR was inhibited only partially. The results indicate that in barley leaves in NiR is induced by NO3- directly, i.e. without being reduced to NO2-, and that absorbed NO2- induces the enzyme activity indirectly after being oxidized to NO3- within the leaf.

  12. Anthropogenic oligotrophication via liming: Long-term phosphorus trends in acidified, limed, and neutral reference lakes in Sweden.

    PubMed

    Hu, Qian; Huser, Brian J

    2014-01-01

    Restoration of acidified lakes by liming does not, in many cases, improve productivity to a pre-acidified state. We hypothesize that the poor recovery detected in many of these lakes is due to constrained in-lake phosphorous (P) cycling caused by enhanced precipitation of metals in higher pH, limed waters. Long-term (1990-2012) data for 65 limed, circum-neutral (pH 6-8), and acidified lakes in Sweden were analyzed to determine trends for P and potential drivers of these trends. Limed lakes not only had lower mean values and stronger decreasing trends for total P than non-limed lakes, but they also had the highest percentage of decreasing trends (85 %). A P release factor (Hypolimnetic P/Epilimnetic P) was developed to elucidate differences in internal P cycling between lake groups. Consistently, lower P release factors in limed lakes show limitation of internal P cycling during summer months that may be a factor limiting P bioavailability and thus productivity of these systems.

  13. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    PubMed Central

    Balk, Melike; Laverman, Anniet M.; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils. PMID:25784903

  14. [Properties of a nitrite reductase inhibitor protein from Pseudomonas aeruginosa].

    PubMed

    Karapetian, A V; Nalbandian, R M

    1993-08-01

    The amino acid composition and major physico-chemical properties of the "nonblue" copper protein isolated earlier from Pseudomonas aeruginosa have been determined. It has been found that the azurin oxidase, cytochrome c551 oxidase and superoxide dismutase activities of the enzyme are inhibited by this protein. The inhibition seems to be due to the protein interaction with the electron-accepting center of nitrite reductase.

  15. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    PubMed

    Balk, Melike; Laverman, Anniet M; Keuskamp, Joost A; Laanbroek, Hendrikus J

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils.

  16. Growth potential of Clostridium perfringens from spores in acidified beef, pork, and poultry products during chilling.

    PubMed

    Juneja, Vijay K; Baker, David A; Thippareddi, H; Snyder, O Peter; Mohr, Tim B

    2013-01-01

    The ability of Clostridium perfringens to germinate and grow in acidified ground beef as well as in 10 commercially prepared acidified beef, pork, and poultry products was assessed. The pH of ground beef was adjusted with organic vinegar to achieve various pH values between 5.0 and 5.6; the pH of the commercial products ranged from 4.74 to 6.35. Products were inoculated with a three-strain cocktail of C. perfringens spores to achieve ca. 2-log (low) or 4-log (high) inoculum levels, vacuum packaged, and cooled exponentially from 54.4 to 7.2°C for 6, 9, 12, 15, 18, or 21 h to simulate abusive cooling; the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) recommends a cooling time of 6.5 h. Total germinated C. perfringens populations were determined after plating on tryptose-sulfite-cycloserine agar and incubating the plates anaerobically at 37°C for 48 h. In addition, C. perfringens growth from spores was assessed at an isothermal temperature of 44°C. Growth from spores was inhibited in ground beef with a pH of 5.5 or below, even during extended cooling from 54.4 to 7.2°C in 21 h. In ground beef with a pH of 5.6, the growth was >1 log after 18 h of cooling from 54.4 to 7.2°C. However, 15 h of cooling controlled the growth to <1 log, regardless of the inoculum level. In addition, no growth was observed in any product with a pH ranging from 4.74 to 5.17, both during exponential abusive cooling periods of up to 21 h and during storage for 21 h at 44°C. While <1-log growth of C. perfringens from spores was observed in the pH 5.63 product cooled exponentially from 54.4 to 7.2°C in 15 h or less, the pH 6.35 product supported growth, even after 6 h of cooling from 54.4 to 7.2°C. These challenge tests demonstrate that adjustment of ground beef to pH of 5.5 or less and of barbeque products to pH of 5.63 or less inhibits C. perfringens spore germination and outgrowth during extended cooling periods from 54.4 to 7.2°C up to 15 h. Therefore

  17. Strong Ion Regulatory Abilities Enable the Crab Xenograpsus testudinatus to Inhabit Highly Acidified Marine Vent Systems

    PubMed Central

    Hu, Marian Y.; Guh, Ying-Jey; Shao, Yi-Ta; Kuan, Pou-Long; Chen, Guan-Lin; Lee, Jay-Ron; Jeng, Ming-Shiou; Tseng, Yung-Che

    2016-01-01

    Hydrothermal vent organisms have evolved physiological adaptations to cope with extreme abiotic conditions including temperature and pH. To date, acid-base regulatory abilities of vent organisms are poorly investigated, although this physiological feature is essential for survival in low pH environments. We report the acid-base regulatory mechanisms of a hydrothermal vent crab, Xenograpsus testudinatus, endemic to highly acidic shallow-water vent habitats with average environment pH-values ranging between 5.4 and 6.6. Within a few hours, X. testudinatus restores extracellular pH (pHe) in response to environmental acidification of pH 6.5 (1.78 kPa pCO2) accompanied by an increase in blood HCO3- levels from 8.8 ± 0.3 to 31 ± 6 mM. Branchial Na+/K+-ATPase (NKA) and V-type H+-ATPase (VHA), the major ion pumps involved in branchial acid-base regulation, showed dynamic increases in response to acidified conditions on the mRNA, protein and activity level. Immunohistochemical analyses demonstrate the presence of NKA in basolateral membranes, whereas the VHA is predominantly localized in cytoplasmic vesicles of branchial epithelial- and pillar-cells. X. testudinatus is closely related to other strong osmo-regulating brachyurans, which is also reflected in the phylogeny of the NKA. Accordingly, our results suggest that the evolution of strong ion regulatory abilities in brachyuran crabs that allowed the occupation of ecological niches in euryhaline, freshwater, and terrestrial habitats are probably also linked to substantial acid-base regulatory abilities. This physiological trait allowed X. testudinatus to successfully inhabit one of the world's most acidic marine environments. PMID:26869933

  18. Multiphase reactivity of gaseous hydroperoxide oligomers produced from isoprene ozonolysis in the presence of acidified aerosols

    NASA Astrophysics Data System (ADS)

    Riva, Matthieu; Budisulistiorini, Sri Hapsari; Zhang, Zhenfa; Gold, Avram; Thornton, Joel A.; Turpin, Barbara J.; Surratt, Jason D.

    2017-03-01

    Ozonolysis of alkenes results in the formation of primary ozonides (POZs), which can subsequently decompose into carbonyl compounds and stabilized Criegee intermediates (sCIs). The sCIs generated from isoprene ozonolysis include the simplest congener, formaldehyde oxide (CH2OO), and isomers of C4-sCI. Although the bimolecular reaction with H2O is expected to be the main fate of sCIs, it was reported that sCIs can also react with carboxylic acids and/or organic hydroperoxides leading to gas-phase oligomeric compounds. While the impact of the gas-phase composition (H2O, sCI scavenger) on the formation of such products was recently studied, their fate remains unclear. In the present work, formation of oligomeric hydroperoxides from isoprene ozonolysis, proposed as reaction products composed of the sCI as a chain unit and formed from the insertion of sCI into a hydroperoxide or a carboxylic acid, was systematically examined in the presence of aerosol with varying compositions. The effect of hydroxyl (OH) radicals on the gas- and particle-phase compositions was investigated using diethyl ether as an OH radical scavenger. Thirty-four oligomeric compounds resulting from the insertion of sCIs into organic hydroperoxides or carboxylic acids were identified using iodide chemical ionization high-resolution mass spectrometry. Large reactive uptake onto acidified sulfate aerosol was observed for most of the characterized gaseous oligomeric species, whereas the presence of organic coatings and the lack of aerosol water significantly reduced or halted the reactive uptake of these species. These results indicate that highly oxidized molecules, such as hydroperoxides, could undergo multiphase reactions, which are significantly influenced by the chemical composition of seed aerosol. Furthermore, in addition to functionalization and accretion, decomposition and re-volatilization should be considered in SOA formation.

  19. Trends in emissions of acidifying species in Asia, 1985-1997.

    SciTech Connect

    Streets, D. G.; Tsai, N. Y.; Akimoto, H.; Oka, K.

    2000-05-31

    Acid deposition is a serious problem throughout much of Asia. Emissions of sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) have been increasing steadily, as nations strive to increase their levels of economic development. Coal and fuel oil have been the main choices for powering industrial development; and, until recently, only a few countries (notably Japan and Taiwan) had taken significant steps to avert the atmospheric emissions that accompany fuel combustion. This paper discusses trends in emissions of SO{sub 2} and NO{sub x} that have occurred in Asian countries in the period 1985--1997, using results from the RAINS-ASIA computer model and energy-use trends from the IEA Energy Statistics and Balances database. Emissions of SO{sub 2} in Asia grew from 26.6 Tg in 1985 to 33.7 Tg in 1990 and to 39.2 Tg in 1997. Though SO{sub 2} emissions used to grow as fast as fossil-fuel use, recent limitations on the sulfur content of coal and oil have slowed the growth. The annual-average emissions growth between 1990 and 1997 was only 1.1%, considerably less than the economic growth rate. Emissions of NO{sub x}, on the other hand, continue to grow rapidly, from 14.1 Tg in 1985 to 18.7 Tg in 1990 and 28.5 Tg in 1997, with no signs of abating. Thus, though SO{sub 2} remains the major contributor to acidifying emissions in Asia, the role of NO{sub x}, will become more and more important in the future.

  20. Experiments and modeling of variably permeable carbonate reservoir samples in contact with CO₂-acidified brines

    DOE PAGES

    Smith, Megan M.; Hao, Yue; Mason, Harris E.; ...

    2014-12-31

    Reactive experiments were performed to expose sample cores from the Arbuckle carbonate reservoir to CO₂-acidified brine under reservoir temperature and pressure conditions. The samples consisted of dolomite with varying quantities of calcite and silica/chert. The timescales of monitored pressure decline across each sample in response to CO₂ exposure, as well as the amount of and nature of dissolution features, varied widely among these three experiments. For all samples cores, the experimentally measured initial permeability was at least one order of magnitude or more lower than the values estimated from downhole methods. Nondestructive X-ray computed tomography (XRCT) imaging revealed dissolution featuresmore » including “wormholes,” removal of fracture-filling crystals, and widening of pre-existing pore spaces. In the injection zone sample, multiple fractures may have contributed to the high initial permeability of this core and restricted the distribution of CO₂-induced mineral dissolution. In contrast, the pre-existing porosity of the baffle zone sample was much lower and less connected, leading to a lower initial permeability and contributing to the development of a single dissolution channel. While calcite may make up only a small percentage of the overall sample composition, its location and the effects of its dissolution have an outsized effect on permeability responses to CO₂ exposure. The XRCT data presented here are informative for building the model domain for numerical simulations of these experiments but require calibration by higher resolution means to confidently evaluate different porosity-permeability relationships.« less

  1. Molecular Cloning of Complementary DNA Encoding Maize Nitrite Reductase

    PubMed Central

    Lahners, Kristine; Kramer, Vance; Back, Eduard; Privalle, Laura; Rothstein, Steven

    1988-01-01

    Complementary DNA has been isolated that codes for maize nitrite reductase (NiR) by using the corresponding spinach gene (E Back et al. 1988 Mol Gen Genet 212:20-26) as a heterologous probe. The sequences of the complementary DNAs from the two species are 66% homologous while the deduced amino acid sequences are 86% similar when analogous amino acids are included. A high percentage of the differences in the DNA sequences is due to the extremely strong bias in the corn gene to have a G/C base in the third codon position with 559/569 codons ending in a G or C. Using a hydroponic system, maize seedlings grown in the absence of an exogenous nitrogen source were induced with nitrate or nitrite. Nitrate stimulated a rapid induction of the NiR mRNA in both roots and leaves. There is also a considerable induction of this gene in roots upon the addition of nitrite, although under the conditions used the final mRNA level was not as high as when nitrate was the inducer. There is a small but detectable level of NiR mRNA in leaves prior to induction, but no constitutive NiR mRNA can be seen in the roots. Analysis of genomic DNA supports the notion that there are at least two NiR genes in maize. Images Fig. 3 Fig. 4 Fig. 5 PMID:16666376

  2. A sub-minute CZE method to determine nitrate and nitrite in meat products: An alternative for routine analysis.

    PubMed

    Della Betta, Fabiana; Pereira, Lais Morilla; Siqueira, Mariana Araújo; Valese, Andressa Camargo; Daguer, Heitor; Fett, Roseane; Vitali, Luciano; Costa, Ana Carolina Oliveira

    2016-09-01

    A sub-minute capillary zone electrophoresis (CZE) method was optimized and a simple sample preparation procedure based on the extraction of the analytes with water and sodium tetraborate was developed for the simultaneous determination of nitrate and nitrite levels in meat products. The background electrolyte (BGE) was composed of 20mmolL(-1) perchloric acid and 65mmolL(-1) β-alanine at pH3.83. Thiocyanate was used as the internal standard. The proposed method was validated and the uncertainty estimated according to Eurachem guidelines. The run time was only 30s, allowing analyzing more than 25samples/h, the good analytical performance confirms the suitability of the method for the analysis of meat products. One sample presented residual nitrite levels above the limit established by MERCOSUL legislation (150mgkg(-1)). The use of a fast method in association with a simple sample preparation step means that this procedure represents a possible alternative to fulfill the demand for high throughput in routine laboratory analysis.

  3. Determination of trace nitrite ion in water by spectrophotometric method after preconcentration on an organic solvent-soluble membrane filter.

    PubMed

    Gu, X; Zhou, T; Qi, D

    1996-02-01

    A simple and rapid preconcentration technique, based on collecting trace nitrite on a membrane filter and dissolving the membrane filter in an organic solvent, has been applied to its spectrophotometric determination in water. At pH 2.0, nitrous acid diazotizes with p-aminoacetophenone. which is then coupled with N-(1-naphthyl)ethylenediamine, at the same pH. The azo dye formed is collected on a 0.45 urn nitrocellulose filter at pH 4.7 as its ion associate with dodecyl sulfate. The ion associate and filter are dissolved in a small volume of 2-methoxyethanol (methylcellosolve), and acidized with 0.05 ml of 2 M hydrochloric acid and the absorbance of the resulting solution is measured at 555 nm against a reagent blank. Detection limits better than O.1 mug/dm(-3) as NO(2)(-) can be achieved. The ions normally present in water do not interfere when sodium metaphosphate is added as a masking agent. The proposed method has been applied to the analysis of water samples from several sources, the recoveries of the nitrite added to the samples are quantitative, and results found are satisfactory.

  4. The metabolic impact of extracellular nitrite on aerobic metabolism of Paracoccus denitrificans.

    PubMed

    Hartop, K R; Sullivan, M J; Giannopoulos, G; Gates, A J; Bond, P L; Yuan, Z; Clarke, T A; Rowley, G; Richardson, D J

    2017-02-07

    Nitrite, in equilibrium with free nitrous acid (FNA), can inhibit both aerobic and anaerobic growth of microbial communities through bactericidal activities that have considerable potential for control of microbial growth in a range of water systems. There has been much focus on the effect of nitrite/FNA on anaerobic metabolism and so, to enhance understanding of the metabolic impact of nitrite/FNA on aerobic metabolism, a study was undertaken with a model denitrifying bacterium Paracoccus denitrificans PD1222. Extracellular nitrite inhibits aerobic growth of P. denitrificans in a pH-dependent manner that is likely to be a result of both nitrite and free nitrous acid (pKa = 3.25) and subsequent reactive nitrogen oxides generated from the intracellular passage of FNA into P. denitrificans. Increased expression of a gene encoding a flavohemoglobin protein (Fhp) (Pden_1689) was observed in response to extracellular nitrite. Construction and analysis of a deletion mutant established Fhp to be involved in endowing nitrite/FNA resistance at high extracellular nitrite concentrations. Global transcriptional analysis confirmed nitrite-dependent expression of fhp and indicated that P. denitrificans expressed a number of stress response systems associated with protein, DNA and lipid repair. It is therefore suggested that nitrite causes a pH-dependent stress response that is due to the production of associated reactive nitrogen species, such as nitric oxide from the internalisation of FNA.

  5. Chronic Exercise Downregulates Myocardial Myoglobin and Attenuates Nitrite Reductase Capacity During Ischemia-Reperfusion

    PubMed Central

    Nicholson, Chad K.; Lambert, Jonathan P.; Chow, Chi-Wing; Lefer, David J.; Calvert, John W.

    2013-01-01

    Background The infarct sparing effects of exercise are evident following both long-term and short-term training regimens. Here we compared the infarct-lowering effects of nitrite therapy, voluntary exercise, and the combination of both following myocardial ischemia-reperfusion (MI/R) injury. We also compared the degree to which each strategy increased cardiac nitrite levels, as well as the effects of each strategy on the nitrite reductase activity of the heart. Methods and Results Mice subjected to voluntary wheel running (VE) for 4 weeks displayed an 18% reduction in infarct size when compared to sedentary mice, whereas mice administered nitrite therapy (25 mg/L in drinking water) showed a 53% decrease. However, the combination of VE and nitrite exhibited no further protection than VE alone. Although the VE and nitrite therapy mice showed similar nitrite levels in the heart, cardiac nitrite reductase activity was significantly reduced in the VE mice. Additionally, the cardiac protein expression of myoglobin, a known nitrite reductase, was also reduced after VE. Further studies revealed that cardiac NFAT activity was lower after VE due to a decrease in calcineurin activity and an increase in GSK3β activity. Conclusion These data suggest that VE downregulates cardiac myoglobin levels by inhibiting calcineurin/NFAT signaling. Additionally, these results suggest that the modest infarct sparing effects of VE are the result of a decrease in the hearts ability to reduce nitrite to nitric oxide during MI/R. PMID:23962643

  6. Kinetic Characterization of Nitrite Uptake and Reduction by Chlamydomonas reinhardtii1

    PubMed Central

    Córdoba, Francisco; Cárdenas, Jacobo; Fernández, Emilio

    1986-01-01

    Kinetics of nitrite uptake and reduction by Chlamydomonas reinhardtii cells growing phototrophically has been studied by means of progress curves and the Michaelis-Menten integrated equation. Both uptake and reduction processes exhibited hyperbolic saturation kinetics, the nitrite uptake system lacking a diffusion component. Nitrite uptake and reduction showed significant differences in Ks for nitrite at pH 7.5 (1.6 versus 20 micromolar, respectively), optimal pH, activation energy values, and sensitivity toward reagents of sulfhydryl groups. Ks values for nitrite uptake were halved in cells subjected to darkness or to nitrogen-starvation. Nitrate inhibited nitrite uptake by a partially competitive mechanism. The same inhibition pattern was found for nitrite uptake by C. reinhardtii mutant 305 cells incapable of nitrate assimilation. The results demonstrate that C. reinhardtii cells take up nitrite via a highly specific carrier, probably energy-dependent, kinetically responsive to environmental changes, distinguishable from the enzymic nitrite reduction and endowed with an active site for nitrite not usable for nitrate transport. PMID:16665164

  7. Ammonia stimulates growth and nitrite-oxidizing activity of Nitrobacter winogradskyi

    PubMed Central

    Ma, Shouguang; Zhang, Demin; Zhang, Wenjun; Wang, Yinong

    2014-01-01

    The aim of this study was to obtain a nitrite-oxidizing bacterium with high nitrite oxidation activity for controlling nitrite levels. A nitrite-oxidizing bacterium, ZS-1, was isolated from the water of a coastal Pseudosciaena crocea-rearing pond. The strain was identified as Nitrobacter winogradskyi based on the phylogenetic analyses of the 16S ribosomal ribonucleic acid gene and nxrA sequence of ZS-1. Under aerobic condition, the nitrite-oxidizing activity of ZS-1 did not change considerably in the range of pH 7–9, but was strongly inhibited by lower (pH = 6) and higher (pH = 10) pH values. The optimum temperature range is 25–32 °C. Lower temperature made the adaptive phase of ZS-1 longer but did not affect its maximum nitrite oxidization rate. The nitrite-oxidizing activity of ZS-1 started to be inhibited by ammonia and nitrate when the concentrations of ammonia and nitrate reached 25 mg L−1 and 100 mg L−1, respectively. The inhibition was stronger with higher concentration of ammonia or nitrate. The nitrite-oxidizing activity of ZS-1, however, was not inhibited by high concentration of nitrite (500 mg L−1). The nitrite-oxidizing activity of ZS-1 was increased by low ammonia concentration (1 mg L−1 to 10 mg L−1). PMID:26019486

  8. Dietary Nitrite Restores NO Homeostasis and is Cardioprotective in eNOS Deficient Mice

    PubMed Central

    Bryan, Nathan S.; Calvert, John W.; Gundewar, Susheel; Lefer, David J.

    2008-01-01

    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. PMID:18501719

  9. Nitrite reduction and formation of corrosion coatings in zerovalent iron systems.

    PubMed

    Huang, Yong H; Zhang, Tian C

    2006-08-01

    Batch tests were conducted to investigate nitrite reduction in a zerovalent iron (Fe0) system under various conditions. Nitrite at 1.4 mM initial concentration was slowly reduced to nitrogen gas in the first stage (days 1-6), which was mediated by an amorphous, Fe(II)-rich iron oxide coating. The second stage (days 7-14) featured a rapid reduction of nitrite to both ammonia and nitrogen gas and the formation of a more crystalline, magnetite form iron oxide coating. Water reduction by Fe0 occurred concurrently with nitrite reduction from the beginning and contributed significantly to the overall iron corrosion. Nitrite at 14 mM was found to passivate the surface of Fe0 grains with respect to nitrite reduction. Adding aqueous Fe2+ significantly accelerated reduction of nitrite by Fe0 to nitrogen gas with lepidocrocite as the main iron corrosion product. Substantially, though still substoichiometrically, 0.55 mol of Fe2+ were concomitantly consumed per 1.0 mol nitrite reduction, indicating that Fe0 was the main electron source. In the presence of Fe2+, nitrite reduction out-competed water reduction in terms of contributing to the overall iron corrosion. Results of this study help understand complicated interactions between water reduction and nitrite reduction, the roles of surface-bound Fe2+, and the evolution of the iron corrosion coating.

  10. Doped with Sodium Acetate and Metallic Sodium

    NASA Astrophysics Data System (ADS)

    Tada, Satoki; Isoda, Yukihiro; Udono, Haruhiko; Fujiu, Hirofumi; Kumagai, Shunji; Shinohara, Yoshikazu

    2014-06-01

    We have investigated the thermoelectric properties of p-type Na-doped Mg2 Si0.25Sn0.75 solid solutions prepared by liquid-solid reaction and hot-pressing methods. Na was introduced into Mg2Si0.25Sn0.75 by using either sodium acetate (CH3COONa) or metallic sodium (2 N). The samples doped with sodium acetate consisted of phases with antifluorite structure and a small amount of MgO as revealed by x-ray diffraction, whereas the sample doped with metallic sodium contained the Sn, MgO, and Mg2SiSn phases. The hole concentrations of Mg1.975Na0.025Si0.25Sn0.75 doped by sodium acetate and metallic sodium were 1.84 × 1025 m-3 and 1.22 × 1025 m-3, respectively, resulting in resistivities of 4.96 × 10-5 Ω m (sodium acetate) and 1.09 × 10-5 Ω m (metallic sodium). The Seebeck coefficients were 198 μV K-1 (sodium acetate) and 241 μV K-1 (metallic sodium). The figures of merit for Mg1.975Na0.025Si0.25Sn0.75 were 0.40 × 10-3 K-1 (sodium acetate) and 0.25 × 10-3 K-1 (metallic sodium) at 400 K. Thus, sodium acetate is a suitable Na dopant for Mg2Si1- x Sn x .

  11. Implications of Limited Thermophilicity of Nitrite Reduction for Control of Sulfide Production in Oil Reservoirs

    PubMed Central

    Fida, Tekle Tafese; Chen, Chuan; Okpala, Gloria

    2016-01-01

    ABSTRACT Nitrate reduction to nitrite in oil fields appears to be more thermophilic than the subsequent reduction of nitrite. Concentrated microbial consortia from oil fields reduced both nitrate and nitrite at 40 and 45°C but only nitrate at and above 50°C. The abundance of the nirS gene correlated with mesophilic nitrite reduction activity. Thauera and Pseudomonas were the dominant mesophilic nitrate-reducing bacteria (mNRB), whereas Petrobacter and Geobacillus were the dominant thermophilic NRB (tNRB) in these consortia. The mNRB Thauera sp. strain TK001, isolated in this study, reduced nitrate and nitrite at 40 and 45°C but not at 50°C, whereas the tNRB Petrobacter sp. strain TK002 and Geobacillus sp. strain TK003 reduced nitrate to nitrite but did not reduce nitrite further from 50 to 70°C. Testing of 12 deposited pure cultures of tNRB with 4 electron donors indicated reduction of nitrate in 40 of 48 and reduction of nitrite in only 9 of 48 incubations. Nitrate is injected into high-temperature oil fields to prevent sulfide formation (souring) by sulfate-reducing bacteria (SRB), which are strongly inhibited by nitrite. Injection of cold seawater to produce oil creates mesothermic zones. Our results suggest that preventing the temperature of these zones from dropping below 50°C will limit the reduction of nitrite, allowing more effective souring control. IMPORTANCE Nitrite can accumulate at temperatures of 50 to 70°C, because nitrate reduction extends to higher temperatures than the subsequent reduction of nitrite. This is important for understanding the fundamentals of thermophilicity and for the control of souring in oil fields catalyzed by SRB, which are strongly inhibited by nitrite. PMID:27208132

  12. Validation of a method to directly and specifically measure nitrite in biological matrices.

    PubMed

    Almeida, Luis E F; Kamimura, Sayuri; Kenyon, Nicholas; Khaibullina, Alfia; Wang, Li; de Souza Batista, Celia M; Quezado, Zenaide M N

    2015-02-15

    The bioactivity of nitric oxide (NO) is influenced by chemical species generated through reactions with proteins, lipids, metals, and its conversion to nitrite and nitrate. A better understanding of the functions played by each of these species could be achieved by developing selective assays able of distinguishing nitrite from other NO species. Nagababu and Rifkind developed a method using acetic and ascorbic acids to measure nitrite-derived NO in plasma. Here, we adapted, optimized, and validated this method to assay nitrite in tissues. The method yielded linear measurements over 1-300 pmol of nitrite and was validated for tissue preserved in a nitrite stabilization solution composed of potassium ferricyanide, N-ethylmaleimide and NP-40. When samples were processed with chloroform, but not with methanol, ethanol, acetic acid or acetonitrile, reliable and reproducible nitrite measurements in up to 20 sample replicates were obtained. The method's accuracy in tissue was ≈ 90% and in plasma 99.9%. In mice, during basal conditions, brain, heart, lung, liver, spleen and kidney cortex had similar nitrite levels. In addition, nitrite tissue levels were similar regardless of when organs were processed: immediately upon collection, kept in stabilization solution for later analysis or frozen and later processed. After ip nitrite injections, rapidly changing nitrite concentrations in tissue and plasma could be measured and were shown to change in significantly distinct patterns. This validated method could be valuable for investigations of nitrite biology in conditions such as sickle cell disease, cardiovascular disease, and diabetes, where nitrite is thought to play a role.

  13. Nitric oxide from nitrite photolysis in the central equatorial Pacific

    NASA Astrophysics Data System (ADS)

    Zafiriou, O. C.; McFarland, M.

    1981-04-01

    Sunlight photolyzes nitrite in seawater: NO2- + HOH + hv = NO + OH + OH-. We studied nitrite loss and nitric oxide production attributed to this reaction in surface waters of the equatorial Pacific near 170°W. Net photochemical loss rates of 2-15% per day were derived from two different types of laboratory incubation experiments. The net nitrite loss rate in the surface water of this region is calculated to average 4 × 10-13 mol l-l s-l during the day, or ˜6 × 10-2 mol m-2 y-1. Nitric oxide was detected in situ with a floating gas-seawater equilibrator. NO was always detectable in nitrite-containing seawater during the day but was undetectable at night or in nitrite-free water. Near sunrises and sunsets the estimated NO vapor pressure, pNO(sea) covaried with the ambient UV insolation in air according to log pNO(sea) = a log UVair + b. Best-fit values to the in situ data indicate a ≈ 1 with r2 ≥ 0.9; simple kinetic models rationalize a values of O, ½, or 1. During the day, pNO(sea) averaged ˜3.1 × 10-8 atm, corresponding to ˜4.6 × 10-11 M [NO]aq. The ambient atmospheric pNO was ˜104 -fold lower, implying a substantial seawater supersaturation and a sea → air flux. From the stagnant-boundary layer model and our measurements, we estimate ˜2 × 10-16 mol 1-1 s-1 (˜1.3 × 108 molecule cm-2 s-1) of NO efflux in daylight, an insignificant NO loss from the sea. The photochemical NO source and the estimated dark reaction sink are, within the accuracy of the data, in balance. These results provide evidence for the presence of NO, a free radical, in surface seawater. They substantiate that photochemical reactions produce measurable concentrations of reactive intermediates in surface seawater and that these enter into rapid secondary reactions. These processes may reach sufficient intensity to provide significant effects, such as sea → air fluxes.

  14. [Sodium azide--clinical course of the poisoning and treatment].

    PubMed

    Łopaciński, Bogdan; Kołacinski, Zbigniew; Winnicka, Renata

    2007-01-01

    Sodium azide poisonings occur very rarely. The mechanism of sodium azide toxic effect has not yet been fully explained. Despite the lack of an explicit procedure for the cases of sodium azide poisonings, in vitro tests and rare case reports suggest that treatment with antidotes for cyanide poisoning victims can be effective. This study describes two cases of suicidal sodium azide ingestion. Case 1. 30-year-old male ingested ca. 180 mg of sodium azide. On admission to hospital, within 4 hours from poisoning, the man complained of dizziness and anxiety. Physical examination revealed horizontal nystagmus, flapping tremor, HR 135/min. In laboratory tests, higher blood concentration of lactates (3 mmol/l) was detected, as well as lower potassium concentration (3.4 mmol/L) and increased transaminase activity (ALT 74 U/l, AST 90 U/l). Electrocardiographic tests showed a negative T wave in limb lead III. Other results were within normal. As the patient ingested a toxic dose of sodium azide, he was treated according to the therapy prescription for cyanide poisoning (amyl nitrite inhalation followed by intravenous administration of sodium nitrite and sodium thiosulphate). ECG record of the last day of hospitalization (7th day of treatment) showed negative T waves in lead III, V4-V6. He was discharged from hospital in good condition. Case 2.23-year-old male ingested 10 g of sodium azide 1.5 hours prior to admission to hospital. At the beginning, the patient's condition was good, but it changed to critical state within the first hours of hospitalization. He developed a deep coma, respiratory and circulatory insufficiency, metabolic acidosis, cardiac dysrrhythmias and anuria. Cardiac activity monitoring showed alternating tachycardia (140 beats per minute) and bradycardia (48 beats per minute), numerous additional supraventricular and ventricular extrasystoles and sinus dysrrhythmia. Cardiac arrest (asystolia) occurred twice, the second incident with fatal outcome. The patient

  15. Function of the Rhizobium etli CFN42 nirK gene in nitrite metabolism.

    PubMed

    Bueno, E; Gómez-Hernández, N; Girard, L; Bedmar, E J; Delgado, M J

    2005-02-01

    Rhizobium etli CFN42 is not capable of growing anaerobically with nitrate but it grows with nitrite as a terminal electron acceptor. This bacterium contains the nirK gene encoding the copper-containing Nir (nitrite reductase), which is located on the cryptic plasmid pCFN42f. Mutational analysis has demonstrated that a nirK deficient mutant was not capable of growing under nitrite-respiring conditions. Moreover, microaerobic growth of this mutant was inhibited by the presence of nitrite. Nir activity and nitrite uptake were highly diminished in a nirK mutant, compared with the wild-type levels after incubation under anaerobic conditions. Our results suggest that the copper-containing Nir may have both a respiratory and a nitrite-detoxifying role in R. etli.

  16. Nitrite survival and nitrous oxide production of denitrifying phosphorus removal sludges in long-term nitrite/nitrate-fed sequencing batch reactors.

    PubMed

    Wang, Yayi; Zhou, Shuai; Ye, Liu; Wang, Hong; Stephenson, Tom; Jiang, Xuxin

    2014-12-15

    Nitrite-based phosphorus (P) removal could be useful for innovative biological P removal systems where energy and carbon savings are a priority. However, using nitrite for denitrification may cause nitrous oxide (N2O) accumulation and emissions. A denitrifying nitrite-fed P removal system [Formula: see text] was successfully set up in a sequencing batch reactor (SBR) and was run for 210 days. The maximum pulse addition of nitrite to [Formula: see text] was 11 mg NO2(-)-N/L in the bulk, and a total of 34 mg NO2(-)-N/L of nitrite was added over three additions. Fluorescent in situ hybridization results indicated that the P-accumulating organisms (PAOs) abundance was 75 ± 1.1% in [Formula: see text] , approximately 13.6% higher than that in a parallel P removal SBR using nitrate [Formula: see text] . Type II Accumulibacter (PAOII) (unable to use nitrate as an electron acceptor) was the main PAOs species in [Formula: see text] , contributing 72% to total PAOs. Compared with [Formula: see text] , [Formula: see text] biomass had enhanced nitrite/free nitrous acid (FNA) endurance, as demonstrated by its higher nitrite denitrification and P uptake rates. N2O accumulated temporarily in [Formula: see text] after each pulse of nitrite. Peak N2O concentrations in the bulk for [Formula: see text] were generally 6-11 times higher than that in [Formula: see text] ; these accumulations were rapidly denitrified to nitrogen gases. N2O concentration increased rapidly in nitrate-cultivated biomass when 5 or 10 mg NO2(-)-N/L per pulse was added. Whereas, N2O accumulation did not occur in nitrite-cultivated biomass until up to 30 mg NO2(-)-N/L per pulse was added. Long-term acclimation to nitrite and pulse addition of nitrite in [Formula: see text] reduced the risk of nitrite accumulation, and mitigated N2O accumulation and emissions from denitrifying P removal by nitrite.

  17. The most acidified Austrian lake in comparison to a neutralized mining lake

    PubMed Central

    Moser, Michael; Weisse, Thomas

    2011-01-01

    This study investigated two mining lakes located in the north of Lower Austria. These lakes arose 45 years ago when open cast lignite mining ceased. The lakes are separated by a 7-m wide dam. Due to the oxidation of pyrite, both lakes have been acidified and exhibit iron, sulphate, and heavy metal concentrations several orders of magnitude higher than in circumneutral lakes. The water column of both lakes is divided into two layers by a pronounced chemocline. The smaller mining lake (AML), with pH close to of 2.6, is the most acidic lake in Austria, whereas flooding with stream water and by drainage from the surrounding fields neutralized the adjacent larger pit lake. The goal of our study was to investigate the effect of flooding on its physical, chemical and biological properties, in comparison to the pristine AML. Even relative to other extremely acidic lakes, the flora and fauna in the AML was reduced and composed of only two flagellate, one ciliate, and one rotifer species. The simplified pelagic food web in the mixolimnion consisted of heterotrophic bacteria, the mixotrophic flagellates Chlamydomonas acidophila and Ochromonas sp., the ciliate Oxytricha sp., and the rotifer Cephalodella sp. The latter two are as yet undescribed new species. The heliozoan Actinophrys sp. that may act as top predator occurred only in low abundance. The euglenid Lepocinclis buetschlii formed a stable deep chlorophyll maximum (DCM) at 7 m depth. Highest cell numbers of L. buetschlii in the DCM exceeded 108 L−1. The neutralized mining lake harboured higher plankton diversity similar to that of natural circumneutral lakes. A peak of at least 16 different phytoplankton taxa was observed during summer. The zooplankton consisted of several copepod species, daphnids and other cladocerans, and at least six different rotifer species. Several fish species occurred in the neutralized lake. Although the effect of non-permanent flooding was largely sustainable, interannual fluctuations of

  18. The most acidified Austrian lake in comparison to a neutralized mining lake.

    PubMed

    Moser, Michael; Weisse, Thomas

    2011-12-01

    This study investigated two mining lakes located in the north of Lower Austria. These lakes arose 45 years ago when open cast lignite mining ceased. The lakes are separated by a 7-m wide dam. Due to the oxidation of pyrite, both lakes have been acidified and exhibit iron, sulphate, and heavy metal concentrations several orders of magnitude higher than in circumneutral lakes. The water column of both lakes is divided into two layers by a pronounced chemocline. The smaller mining lake (AML), with pH close to of 2.6, is the most acidic lake in Austria, whereas flooding with stream water and by drainage from the surrounding fields neutralized the adjacent larger pit lake. The goal of our study was to investigate the effect of flooding on its physical, chemical and biological properties, in comparison to the pristine AML. Even relative to other extremely acidic lakes, the flora and fauna in the AML was reduced and composed of only two flagellate, one ciliate, and one rotifer species. The simplified pelagic food web in the mixolimnion consisted of heterotrophic bacteria, the mixotrophic flagellates Chlamydomonas acidophila and Ochromonas sp., the ciliate Oxytricha sp., and the rotifer Cephalodella sp. The latter two are as yet undescribed new species. The heliozoan Actinophrys sp. that may act as top predator occurred only in low abundance. The euglenid Lepocinclis buetschlii formed a stable deep chlorophyll maximum (DCM) at 7 m depth. Highest cell numbers of L. buetschlii in the DCM exceeded 10(8) L(-1). The neutralized mining lake harboured higher plankton diversity similar to that of natural circumneutral lakes. A peak of at least 16 different phytoplankton taxa was observed during summer. The zooplankton consisted of several copepod species, daphnids and other cladocerans, and at least six different rotifer species. Several fish species occurred in the neutralized lake. Although the effect of non-permanent flooding was largely sustainable, interannual fluctuations

  19. Modifications of Carbonate Fracture Hydrodynamic Properties by CO 2 -Acidified Brine Flow

    SciTech Connect

    Deng, Hang; Ellis, Brian R.; Peters, Catherine A.; Fitts, Jeffrey P.; Crandall, Dustin; Bromhal, Grant S.

    2013-08-15

    Acidic reactive flow in fractures is relevant in subsurface activities such as CO{sub 2} geological storage and hydraulic fracturing. Understanding reaction-induced changes in fracture hydrodynamic properties is essential for predicting subsurface flows such as leakage, injectability, and fluid production. In this study, x-ray computed tomography scans of a fractured carbonate caprock were used to create three dimensional reconstructions of the fracture before and after reaction with CO{sub 2}-acidified brine (Ellis et al., 2011, Greenhouse Gases: Sci. Technol., 1:248-260). As expected, mechanical apertures were found to increase substantially, doubling and even tripling in some places. However, the surface geometry evolved in complex ways including ‘comb-tooth’ structures created from preferential dissolution of calcite in transverse sedimentary bands, and the creation of degraded zones, i.e. porous calcite-depleted areas on reacted fracture surfaces. These geometric alterations resulted in increased fracture roughness, as measured by surface Z{sub 2} parameters and fractal dimensions D{sub f}. Computational fluid dynamics (CFD) simulations were conducted to quantify the changes in hydraulic aperture, fracture transmissivity and permeability. The results show that the effective hydraulic apertures are smaller than the mechanical apertures, and the changes in hydraulic apertures are nonlinear. Overestimation of flow rate by a factor of two or more would be introduced if fracture hydrodynamic properties were based on mechanical apertures, or if hydraulic aperture is assumed to change proportionally with mechanical aperture. The differences can be attributed, in part, to the increase in roughness after reaction, and is likely affected by contiguous transverse sedimentary features. Hydraulic apertures estimated by the 1D statistical model and 2D local cubic law (LCL) model are consistently larger than those calculated from the CFD simulations. In addition, a novel

  20. Can the eastern red-backed salamander (Plethodon cinereus) persist in an acidified landscape?

    USGS Publications Warehouse

    Bondi, Cheryl A; Beier, Colin M.; Ducey, Peter K; Lawrence, Gregory B.; Bailey, Scott W.

    2016-01-01

    Hardwood forests of eastern North America have experienced decades of acidic deposition, leading to soil acidification where base cation supply was insufficient to neutralize acid inputs. Negative impacts of soil acidity on amphibians include disrupted embryonic development, lower growth rates, and habitat loss. However, some amphibians exhibit intraspecific variation in acid tolerance, suggesting the potential for local adaptation in areas where soils are naturally acidic. The eastern red-backed salamander (Plethodon cinereus) is a highly abundant top predator of the northern hardwood forest floor. Early research found that P. cinereus was sensitive to acidic soils, avoiding substrates with pH < 3.8 and experiencing decreased growth rates in acidic habitats. However, recent studies have documented P. cinereus populations in lower pH conditions than previously observed, suggesting some populations may persist in acidic conditions. Here, we evaluated relationships between organic horizon soil pH and P. cinereus abundance, adult health (body size and condition), and microhabitat selection, based on surveys of 34 hardwood forests in northeastern United States that encompass a regional soil pH gradient. We found no associations between soil pH and P. cinereus abundance or health, and observed that this salamander used substrates with pH similar to that available, suggesting that pH does not mediate their fine-scale distributions. The strongest negative predictor of P. cinereus abundance was the presence of dusky salamanders (Desmognathus spp.), which were most abundant in the western Adirondacks. Our results indicate that P. cinereus occupies a wider range of soil pH than has been previously thought, which has implications for their functional role in forest food webs and nutrient cycles in acid-impaired ecosystems. Tolerance of P. cinereus for more acidic habitats, including anthropogenically acidified forests, may be due to local adaptation in

  1. A "liver" antigen associated with avian erythroblastosis: binding by bentonite and precipitation with sodium dodecyl sulphate.

    PubMed Central

    Darcel, C L

    1982-01-01

    The properties of a complement fixing antigen, EbAg, extracted from erythroblastosis-affected chicken livers are described. The antigen in extracts freed of structural protein is strongly bound by bentonite, but not by barium sulphate. Strongly alkaline solutions of sodium dodecyl sulphate are required to release the antigen from bentonite. Acidification of the detergent solution precipitates the active solution precipitates the active protein. Extraction of heme from the acidified detergent precipitate by methyl-ethyl ketone further purifies the antigen. This acid detergent treatment eliminates the need to use bentonite as a purification step. PMID:6280825

  2. Modelling nitrite dynamics and associated feedback processes in the Benguela oxygen minimum zone

    NASA Astrophysics Data System (ADS)

    Mashifane, T. B.; Vichi, M.; Waldron, H. N.; Machu, E.; Garçonc, V.

    2016-08-01

    Understanding nitrite dynamics in oxygen minimum zones (OMZs) is a challenge as it represents an intermediary nitrogen species with a short turnover time. Nitrite is also reduced to nitrogen in OMZs, preventing its accumulation. This creates difficulties in detecting nitrite with colorimetric methods as concentrations may occur below detection limits in some regions. Nitrite concentrations are key to understanding intermediate nitrogen processes and their implication for nitrogen loss in OMZs. A coupled physical-biogeochemical model is applied in the Benguela OMZ to study nitrite dynamics and its associated feedback processes. Simulated results show occurrence of primary and secondary nitrite maxima in the Benguela shelf waters. The primary nitrite maxima in the Benguela are attributed to nitrification and nitrate assimilation as they occur in association with the nitracline. Secondary nitrite maxima accumulate in the Angola-Benguela Front (ABF) OMZ and are attributed to denitrification. The secondary nitrite maxima are consumed by anaerobic ammonium oxidation (anammox) off Walvis Bay. Nitrite maxima are restricted to the shelf off Walvis Bay and advected offshore in the ABF region. Interchanges between the poleward South Atlantic Central Water (SACW) and the equatorward, well-aerated Eastern South Atlantic Central Water (ESACW) drive the seasonality of nitrogen processes in the Benguela. Subsequent nitrite reduction in the Benguela OMZ leads to nitrous oxide production, with high concentrations occurring in the ABF region as a result of nitrification and denitrification. Off Walvis Bay, nitrous oxide production is low since nitrite is consumed by anammox. Nitrous oxide production occurs in thermocline, intermediate and deeper water masses in the ABF region. High N fluxes in the Benguela are attributed to nitrification as compared to anammox and denitrification. Results from this study demonstrate the role of intermediate nitrogen species in nitrogen feedback

  3. Effects of Lactic Acid Bacteria on Residual Nitrite in a Summer Style Sausage.

    DTIC Science & Technology

    1984-01-01

    Lactobacillus leichmannii, Streptococcus faecalis, and several atypical lactobacilli isolated from fresh beef and mutton reduced 200-1000 ppm nitrite...faecalis and an atypical lactobacillus isolated from beef) showed abilities to reduce pH and residual nitrite to levels similar to L. plantarum and P...Leuconostoc mesenteroides reduced nitrite at a faster rate than either Lactobacillus plantarum or Lactobacillus viridescens, while Lactobacillus

  4. The presence of ammonium facilitates nitrite reduction under PHB driven simultaneous nitrification and denitrification.

    PubMed

    Gibbs, B M; Shephard, L R; Third, K A; Cord-Ruwisch, R

    2004-01-01

    For economic and efficient nitrogen removal from wastewater treatment plants via simultaneous nitrification and denitrification the nitrification process should stop at the level of nitrite such that nitrite rather than nitrate becomes the substrate for denitrification. This study aims to contribute to the understanding of the conditions that are necessary to improve nitrite reduction over nitrite oxidation. Laboratory sequencing batch reactors (SBRs) were operated with synthetic wastewater containing acetate as COD and ammonium as the nitrogen source. Computer controlled operation of the reactors allowed reproducible simultaneous nitrification and denitrification (SND). The oxygen supply was kept precisely at a low level of 0.5 mgL(-1) and bacterial PHB was the only electron donor available for denitrification. During SND little nitrite or nitrate accumulated (< 20% total N), indicating that the reducing processes were almost as fast as the production of nitrite and nitrate from nitrification. Nitrite spiking tests were performed to investigate the fate of nitrite under different oxidation (0.1-1.5 mgL(-1) of dissolved oxygen) and reduction conditions. High levels of reducing power were provided by allowing the cells to build up to 2.5 mM of PHB. Nitrite added was preferentially oxidised to nitrate rather than reduced even when dissolved oxygen was low and reducing power (PHB) was excessively high. However, the presence of ammonium enabled significant reduction of nitrite under low oxygen conditions. This is consistent with previous observations in SBR where aerobic nitrite and nitrate reduction occurred only as long as ammonium was present. As soon as ammonium was depleted, the rate of denitrification decreased significantly. The significance of the observed strongly stimulating effect of ammonium on nitrite reduction under SND conditions is discussed and potential consequences for SBR operation are suggested.

  5. Nitrogen removal and electricity production at a double-chamber microbial fuel cell with cathode nitrite denitrification.

    PubMed

    Yu, Yangyang; Zhao, Jianqiang; Wang, Sha; Zhao, Huimin; Ding, Xiaoqian; Gao, Kun

    2017-02-17

    Double-chamber microbial fuel cell was applied to investigate the performance of the electricity production and nitrite denitrification through feeding nitrite into the cathode. Factors influencing denitrification performance and power production, such as external resistance, influent nitrite concentration and Nitrite Oxygen Bacteria inhibitors, were studied. The results show that when the concentration of nitrite nitrogen and external resistance were 100 mg L(-1) and 10 Ω, respectively, the nitrite denitrification reached the best state. The NaN3 can inhibit nitrite oxidation effectively; meanwhile, the nitrite denitrification with N2O as the final products was largely improved. The [Formula: see text] was reduced to [Formula: see text], causing the cathode denitrification coulombic efficiency to exceed 100%. In chemoautotrophic bio-nitrification, microorganisms may utilize H2O to oxidize nitrite under anaerobic conditions. Proteobacteria might play a major role in the process of denitrification in MFC.

  6. Evidence of parallel denitrification and nitrite oxidation in the ODZ of the Arabian Sea from paired stable isotopes of nitrate and nitrite

    NASA Astrophysics Data System (ADS)

    Gaye, Birgit; Nagel, Birgit; Dähnke, Kirstin; Rixen, Tim; Emeis, Kay-Christian

    2013-12-01

    The Arabian Sea is a major oceanic nitrogen sink, and its oxygen-deficient zone (ODZ) extends from 150 m to 1200 m water depth. To identify the dominant transformation processes of reactive nitrogen and to quantify the amounts of nitrogen turned over in the different reactions of the nitrogen cycle, we use paired data on stable isotope ratios of nitrogen and oxygen in nitrate and nitrite measured at four near-coastal and five open ocean stations in the Arabian Sea. We find significant nitrate reduction and denitrification between 100 m and 400 m in the open Arabian Sea, which are most intense in the eastern and northern part of the basin, and estimate that about 50% of initial nitrate is being reduced either to dinitrogen gas (denitrification) or to nitrite (nitrate reduction) in the core zone of denitrification. Nitrite accumulates in concentrations above 4 µM in the water column of the eastern and northern Arabian Sea. Large differences in isotopic ratios of nitrate and nitrite and a decoupling of their stable nitrogen and oxygen isotopes can be explained by the reoxidation of nitrite. The observed decoupling of the paired isotopes may be due to the exchange of oxygen of nitrite with oxygen from ambient water. In agreement with model estimates from the literature, about 25% of the nitrate initially reduced to nitrite is returned to the nitrate pool by nitrification in the upper and lower denitrification layer while 40% is denitrified.

  7. Can Urinary Nitrite Results Be Used to Conduct Antimicrobial Option for Urinary Tract Infection in Children?

    PubMed Central

    Mahyar, Abolfazl; Ayazi, Parviz; Froozesh, Mahta; Daneshi-Kohan, Mohammad-Mahdi; Barikani, Ameneh

    2012-01-01

    Objective This study was performed to determine the relationship between urinary nitrite results and bacterial resistance to antimicrobial drugs in urinary tract infection of children. Methods In a cross-section study 119 children younger than 12 years with urinary tract infection were evaluated in Qazvin children's hospital. Patients were divided into negative and positive nitrite groups depending on urinary nitrite test result. Rates of antibiotic resistance in the two groups were compared. Findings Sixty seven patients were in the negative nitrite group and 52 in the positive nitrite group. Resistance rates to ceftriaxone, trimethoprim sulfamethoxazole, ampicillin, gentamicin, amikacin, nalidixic acid, cephalothin and nitrofurantoin in the nitrite negative group were 7.5%, 31.3%, 50.7%, 11.9%, 9%, 3%, 14.9% and 11.9%, respectively. These values in the nitrite positive group were 21.2%, 28.8%, 63.5%, 7.7%, 5.8%, 1.9%, 9.6%, and 3.8%, respectively (P>0.05). Conclusion This study showed that there is no correlation between urinary nitrite results and bacterial resistance to antimicrobial drugs. Therefore, it seems that physicians should not adjust antibiotic therapy for UTI based on nitrite results. PMID:23056892

  8. The measurement of blood and plasma nitrite by chemiluminescence: pitfalls and solutions.

    PubMed

    Pelletier, Mildred M; Kleinbongard, Petra; Ringwood, Lorna; Hito, Rania; Hunter, Christian J; Schechter, Alan N; Gladwin, Mark T; Dejam, André

    2006-08-15

    There are a number of difficulties involved in the quantification of nitrite in biological systems. These difficulties result from oxidation of nitrite (within minutes) by heme proteins, such as hemoglobin, myoglobin, cytoglobin, and neuroglobin; its low levels in vivo; and its ubiquitous presence in laboratory buffers and glassware. The goal of this review is to present an assay suitable for the sensitive and specific measurement of intravascular nitrite in mammals using the chemiluminescence-based nitric oxide analyzer and to inform the reader on how to evade the pitfalls pertinent to nitrite determination in biological matrices.

  9. Role of blood and vascular smooth muscle in the vasoactivity of nitrite.

    PubMed

    Liu, Taiming; Schroeder, Hobe J; Barcelo, Lisa; Bragg, Shannon L; Terry, Michael H; Wilson, Sean M; Power, Gordon G; Blood, Arlin B

    2014-10-01

    Recent evidence from humans and rats indicates that nitrite is a vasodilator under hypoxic conditions by reacting with metal-containing proteins to produce nitric oxide (NO). We tested the hypothesis that near-physiological concentrations of nitrite would produce vasodilation in a hypoxia- and concentration-dependent manner in the hind limb of sheep. Anesthetized sheep were instrumented to measure arterial blood pressure and femoral blood flows continuously in both hind limbs. Nitrite was infused into one femoral artery to raise the nitrite concentration in the femoral vein by 10 to 15-fold while the sheep breathed 50%, 14% or 12% oxygen in inspired air. In contrast to reports in humans and rats, the nitrite infusion had no measurable effect on mean femoral blood flows or vascular conductances, regardless of inspired O2 levels. In vitro experiments showed no significant difference in the release of NO from nitrite in sheep and human red blood cells. Further experiments demonstrated nitrite is converted to NO in rat artery homogenates faster than sheep arteries, and that this source of NO production is attenuated in the presence of a heme oxidizer. Finally, western blots indicate that concentrations of the heme-containing protein cytoglobin, but not myoglobin, are markedly lower in sheep arteries compared with rats. Overall, the results demonstrate that nitrite is not a physiological vasodilator in sheep. This is likely due to a lack of conversion of nitrite to NO within the vascular smooth muscle, perhaps due to deficient amounts of the heme-containing protein cytoglobin.

  10. Exposure to inhaled isobutyl nitrite reduces T cell-dependent responsiveness

    SciTech Connect

    Soderberg, L.S.F.; Barnett, J.B. )

    1991-03-11

    Isobutyl nitrite is a drug of abuse popular among male homosexuals and among adolescents. In order to approximate the nitrite exposures of inhalant abusers, mice were treated with 900 ppm isobutyl nitrite in an inhalation chamber for 45 min per day for 14 days. At 72 hr after the last exposure, mice were assayed for immune competence. Under these conditions, mice gained only half the weight of mice exposed to air. The spleens of nitrite exposed mice weighed 15% less and had 24% fewer cells per spleen than controls. Adjusted for equal cell numbers, T cell mitogenic and allogeneic proliferative responses were significantly reduce by 33% and 47%, respectively. Unstimulated spleen cells had elevated levels of IL-2 transcription following exposure to isobutyl nitrite suggesting that nitrite inhalation caused a nonspecific induction of T cells. In contrast, B cell proliferative responses to LPS were unaltered. Exposure to the nitrite reduced the frequency of T-dependent antibody plaque-forming cells (PFC) by 63% and the total number of reduced by 60% after as few as five daily exposures to isobutyl nitrite. Therefore, the data suggest that habitual inhalation of isobutyl nitrite impairs immune competence and that toxicity appears to be directed toward T cell functions.

  11. Synthesis and intracrystalline oxidation of nitrite-intercalated layered double hydroxides

    SciTech Connect

    Thomas, Nygil; Pradeep Kumar, G.; Rajamathi, Michael

    2009-03-15

    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.

  12. Pharmacology and therapeutic role of inorganic nitrite and nitrate in vasodilatation.

    PubMed

    Bailey, J C; Feelisch, M; Horowitz, J D; Frenneaux, M P; Madhani, M

    2014-12-01

    Nitrite has emerged as an important bioactive molecule that can be biotransformed to nitric oxide (NO) related metabolites in normoxia and reduced to NO under hypoxic and acidic conditions to exert vasodilatory effects and confer a variety of other benefits to the cardiovascular system. Abundant research is currently underway to understand the mechanisms involved and define the role of nitrite in health and disease. In this review we discuss the impact of nitrite and dietary nitrate on vascular function and the potential therapeutic role of nitrite in acute heart failure.

  13. Production of nitrite from the photodegradation of dissolved organic matter in natural waters

    SciTech Connect

    Kieber, R.J.; Li, A.; Seaton, P.J.

    1999-04-01

    Significant concentrations of nitrite NO{sub 2}{sup {minus}} were produced from the photodegradation of humic substances (HS) isolated from a variety of natural waters in coastal North Carolina. Nitrite concentrations were 40--118% higher after light exposure relative to initial levels, while no statistical differences were observed in dark controls before and after irradiation. The amount of nitrite produced upon irradiation was positively correlated to the concentration of HS added and to the length of irradiation. The average production rate, normalized to both humic substance concentration and time of light exposure, for all HS studied ranged from 9.7 to 17 [nM (W-h){sup {minus}1} m{sup {minus}2} mg{sup {minus}1}] {times} 10{sup 5}. This translates into an average yearly nitrite production of 2 {times} 10{sup 6} mol yr{sup {minus}1} in the top one meter of Onslow Bay. When natural waters were irradiated, changes in nitrite were influenced by both initial nitrite and humic substance concentrations. The rate of nitrite photochemical formation in typical coastal waters was smaller from its direct photolysis rate and smaller than reported rates of ammonium generation via DOM photodegradation and of the same order of magnitude as NH{sub 4}{sup +} incorporation during humification. The photochemical release of biologically available nitrite from biologically refractory humic substances has significant implications with respect to nitrite biogeochemistry and N cycling in natural waters and suggests HS bound N is more biogeochemically labile than previously thought.

  14. Red blood cell membrane-facilitated release of nitrite-derived nitric oxide bioactivity.

    PubMed

    Salgado, Maria T; Cao, Zeling; Nagababu, Enika; Mohanty, Joy G; Rifkind, Joseph M

    2015-11-10

    The reduction of nitrite by deoxyhemoglobin to nitric oxide (NO) has been proposed as a mechanism for the transfer of NO bioactivity from the red blood cell (RBC) to the vasculature. This transfer can increase vascular dilatation. The major challenge to this hypothesis is the very efficient scavenging of NO by hemoglobin, which prevents the release of NO from RBCs. Previous studies indicate that the reaction of nitrite with deoxyhemoglobin produces two metastable intermediates involving nitrite bound to deoxyhemoglobin and a hybrid intermediate [Hb(II)NO(+) ↔ Hb(III)NO] where the nitrite is reduced, but unavailable to react with hemoglobin. We have now shown how unique properties of these intermediates provide a pathway for the release of NO bioactivity from RBCs. The high membrane affinity of these intermediates (>100-fold greater than that of deoxyhemoglobin) places these intermediates on the membrane. Furthermore, membrane-induced conformational changes of the nitrite-reacted intermediates facilitate the release of NO from the hybrid intermediate and nitrite from the nitrite-bound intermediate. Increased membrane affinity, coupled with facilitated dissociation of NO and nitrite from the membrane-bound intermediates, provides the first realistic mechanism for the potential release of NO and nitrite from the RBC and their potential transfer to the vasculature.

  15. Total salivary nitrates and nitrites in oral health and periodontal disease.

    PubMed

    Sánchez, Gabriel A; Miozza, Valeria A; Delgado, Alejandra; Busch, Lucila

    2014-01-30

    It is well known that nitrites are increased in saliva from patients with periodontal disease. In the oral cavity, nitrites may derive partly from the reduction of nitrates by oral bacteria. Nitrates have been reported as a defence-related mechanism. Thus, the aim of the present study was to determine the salivary levels of total nitrate and nitrite and their relationship, in unstimulated and stimulated saliva from periodontal healthy subjects, and from patients with chronic periodontal disease. Nitrates and nitrites were determined in saliva from thirty healthy subjects and forty-four patients with periodontal disease. A significant increase in salivary nitrates and nitrites was observed. Nitrates and nitrites concentration was related to clinical attachment level (CAL). A positive and significant Pearson's correlation was found between salivary total nitrates and nitrites. Periodontal treatment induced clinical improvement and decreased nitrates and nitrites. It is concluded that salivary nitrates and nitrites increase, in patients with periodontal disease, could be related to defence mechanisms. The possibility that the salivary glands respond to oral infectious diseases by increasing nitrate secretion should be explored further.

  16. Directing the mode of nitrite binding to a copper-containing nitrite reductase from Alcaligenes faecalis S-6: characterization of an active site isoleucine.

    PubMed

    Boulanger, Martin J; Murphy, Michael E P

    2003-02-01

    Unlike the heme cd(1)-based nitrite reductase enzymes, the molecular mechanism of copper-containing nitrite reductases remains controversial. A key source of controversy is the productive binding mode of nitrite in the active site. To identify and characterize the molecular determinants associated with nitrite binding, we applied a combinatorial mutagenesis approach to generate a small library of six variants at position 257 in nitrite reductase from Alcaligenes faecalis S-6. The activities of these six variants span nearly two orders of magnitude with one variant, I257V, the only observed natural substitution for Ile257, showing greater activity than the native enzyme. High-resolution (> 1.8 A) nitrite-soaked crystal structures of these variants display different modes of nitrite binding that correlate well with the altered activities. These studies identify for the first time that the highly conserved Ile257 in the native enzyme is a key molecular determinant in directing a catalytically competent mode of nitrite binding in the active site. The O-coordinate bidentate binding mode of nitrite observed in native and mutant forms with high activity supports a catalytic model distinct from the heme cd(1) NiRs. (The atomic coordinates for I257V[NO(2)(-)], I257L[NO(2)(-)], I257A[NO(2)(-)], I257T[NO(2)(-)], I257M[NO(2)(-)] and I257G[NO(2)(-)] AfNiR have been deposited in the Protein Data Bank [PDB identification codes are listed in Table 2].)

  17. Inhibitory effects of nitrite on the reactions of bovine carbonic anhydrase II with CO2 and bicarbonate consistent with zinc-bound nitrite.

    PubMed

    Nielsen, Per M; Fago, Angela

    2015-08-01

    Carbonic anhydrase (CA) is a zinc enzyme that catalyzes hydration of carbon dioxide (CO2) and dehydration of bicarbonate in red blood cells, thus facilitating CO2 transport and excretion. Bovine CA II may also react with nitrite to generate nitric oxide, although nitrite is a known inhibitor of the CO2 hydration reaction. To address the potential in vivo interference of these reactions and the nature of nitrite binding to the enzyme, we here investigate the inhibitory effect of 10-30 mM nitrite on Michaelis-Menten kinetics of CO2 hydration and bicarbonate dehydration by stopped-flow spectroscopy. Our data show that nitrite significantly affects the apparent dissociation constant KM for CO2 (11 mM) and bicarbonate (221 mM), and the turnover number kcat for the CO2 hydration (1.467 × 10(6) s(-1)) but not for the bicarbonate dehydration (7.927 × 10(5) s(-1)). These effects demonstrate mixed and competitive inhibition for the reaction with CO2 and bicarbonate, respectively, and are consistent with nitrite binding to the active site zinc. The high apparent dissociation constant found here for CO2, bicarbonate and nitrite (16-120 mM) are all overall consistent with published data and reveal a large capacity of free enzyme available for binding each of the three substrates at their in vivo levels, with little or no significant interference among reactions. The low affinity of the enzyme for nitrite suggests that the in vivo interaction between red blood cell CA II and nitrite requires compartmentalization at the anion exchanger protein of the red cell membrane to be physiologically relevant.

  18. Ultraviolet absorption spectrum of chlorine nitrite, ClONO

    NASA Technical Reports Server (NTRS)

    Molina, L. T.; Molina, M. J.

    1977-01-01

    The near-ultraviolet absorption spectrum of chlorine nitrite (ClONO) has been quantitatively investigated over the wavelength range 230-400 nm at 231 K. An absorption maximum was observed at 290 nm with a cross section of 1.5 by 10 to the -18th power sq cm. The calculated lifetime against photodissociation for ClONO in the atmosphere is 2 to 3 minutes. The large photolysis rate indicates that ClONO does not play a significant role in the stratosphere as a temporary holding tank for chlorine.

  19. Expression and purification of spinach nitrite reductase in E. coli

    SciTech Connect

    Bellissimo, D.; Privalle, L. )

    1991-03-11

    The study of structure-function relationships in nitrite reductase (NiR) by site-directed mutagenesis requires an expression system from which suitable quantities of active enzyme can be purified. Spinach NiR cDNA was cloned into pUC18 and expressed in E.coli JM109 as a beta-galactosidase fusion protein. The IPTG-induced fusion protein contains five additional amino acids at the N-terminus. The expressed NiR in aerobic cultures was mostly insoluble and inactive indicating the presence of inclusion bodies. By altering growth conditions, active NiR could represent 0.5-1.0% of the total E.coli protein, Effects of the addition of delta-aminolevulinic acid, a heme precursor, and anaerobic growth were also examined. Spinach NiR was purified approximately 200 fold to homogeneity. When subjected to electrophoresis on SDS polyacrylamide gels, the NiR migrated as a single band with similar mobility to pure spinach enzyme. The expressed enzyme also reacted with rabbit anti-spinach NiR antibody as visualized by Western blot analysis. The absorption spectrum of the E.coli-expressed enzyme was identical to spinach enzyme with a Soret and alpha band a 386 and 573 nm, respectively, and an A{sub 278}/A{sub 386} = 1.9. The addition of nitrite produced the characteristic shifts in the spectrum. The E. coli-expressed NiR catalyzed the methylviologen-dependent reduction of nitrite. The specific activity was 100 U/mg. The K{sub m} determined for nitrite was 0.3 mM which is in agreement with values reported for the enzyme. These results indicate that the E.coli-expressed NiR is fully comparable to spinach NiR in purity, catalytic activity and physical state. Site-directed mutants have been made using PCR to examine structure-function relationships in this enzyme.

  20. The heterogeneous kinetics of HOBr and HOCl on acidified sea salt and model aerosol at 40-90% relative humidity and ambient temperature.

    PubMed

    Pratte, Pascal; Rossi, Michel J

    2006-09-14

    The HOBr and HOCl uptake coefficient gamma on H(2)SO(4)-acidified submicron salt aerosol of known size distribution was measured in an atmospheric pressure laminar flow reactor. The interaction time of the trace gas with the aerosol was in the range 15 to 90 s and led to gamma values in the range 10(-4) to 10(-2). The acidity of the aerosol is essential in order to enable heterogeneous reactions of HOBr on NaCl, recrystallized sea salt (RSS) and natural sea salt (NSS) aerosols. Specifically, HOCl only reacts on acidified NSS aerosol with a gamma ranging from 0.4 x 10(-3) to 1.8 x 10(-3) at a relative humidity (rh) at 40 and 85%, respectively. Uptake experiments of HOBr on aqueous H(2)SO(4) as well as on H(2)SO(4)-acidified NaCl, RSS or NSS aerosol were performed for rh ranging from 40 to 93%. The gamma value of HOBr on acidified NSS reaches a maximum gamma = 1.9 x 10(-2) at rh = 76 +/- 1% and significantly decreases with increasing rh in contrast to acidified NaCl and RSS aerosols whose gamma values remain high at gamma = (1.0 +/- 0.2) x 10(-2) at rh >/= 80%. An explanation based on the formation of an organic coating on NSS aerosol with increasing rh is proposed.

  1. Fractional excretion of sodium

    MedlinePlus

    FE sodium; FENa ... to a lab. There, they are examined for salt (sodium) and creatinine levels. Creatinine is a chemical waste ... your normal foods with a normal amount of salt, unless otherwise instructed by your health care provider. ...

  2. Sodium carbonate poisoning

    MedlinePlus

    Sodium carbonate (known as washing soda or soda ash) is a chemical found in many household and ... products. This article focuses on poisoning due to sodium carbonate. This article is for information only. Do ...

  3. Naproxen sodium overdose

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002507.htm Naproxen sodium overdose To use the sharing features on this page, please enable JavaScript. Naproxen sodium is a nonsteroidal anti-inflammatory drug (NSAID) used ...

  4. Sodium Ferric Gluconate Injection

    MedlinePlus

    Sodium ferric gluconate injection is used to treat iron-deficiency anemia (a lower than normal number of ... are also receiving the medication epoetin (Epogen, Procrit). Sodium ferric gluconate injection is in a class of ...

  5. Sodium hydroxide poisoning

    MedlinePlus

    Sodium hydroxide is a very strong chemical. It is also known as lye and caustic soda. This ... poisoning from touching, breathing in (inhaling), or swallowing sodium hydroxide. This article is for information only. Do ...

  6. Diclofenac sodium overdose

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002630.htm Diclofenac sodium overdose To use the sharing features on this page, please enable JavaScript. Diclofenac sodium is a prescription medicine used to relieve pain ...

  7. Docusate Sodium and Pregnancy

    MedlinePlus

    ... live chat Live Help Fact Sheets Share Docusate Sodium Friday, 01 April 2016 In every pregnancy, a ... This sheet talks about whether exposure to docusate sodium may increase the risk for birth defects over ...

  8. Low sodium level

    MedlinePlus

    ... osmolality Urine sodium Treatment The cause of low sodium must be diagnosed and treated. If cancer is the cause of the condition, then radiation, chemotherapy , or surgery to remove the tumor may correct the sodium imbalance. Other treatments depend on the specific type ...

  9. Mechanisms for Cellular NO Oxidation and Nitrite Formation in Lung Epithelial Cells

    PubMed Central

    Zhao, Xue-Jun; Wang, Ling; Shiva, Sruti; Tejero, Jesus; Wang, Jun; Frizzell, Sam; Gladwin, Mark T.

    2013-01-01

    Airway lining fluid contains relatively high concentrations of nitrite and arterial blood levels of nitrite are higher than venous levels, suggesting the lung epithelium may represent an important source of nitrite in vivo. To investigate whether lung epithelial cells possess the ability to convert NO to nitrite by oxidation, and the effect of oxygen reactions on nitrite formation, the NO donor DETA NONOate was incubated with or without A549 cells or primary human bronchial epithelial (HBE) cells for 24 hrs under normoxic (21% O2) and hypoxic (1% O2) conditions. Nitrite production was significantly increased under all conditions in the presence of A549 or HBE cells, suggesting that both A549 and HBE cells have the capacity to oxidize NO to nitrite even under low oxygen conditions. The addition of oxy-hemoglobin (oxy-Hb) to the A549 cell media decreased the production of nitrite, consistent with NO scavenging limiting nitrite formation. Heat-denatured A549 cells produced much lower nitrite and bitrate, suggesting an enzymatic activity is required. This NO oxidation activity was found to be highest in membrane bound proteins with molecular sizes < 100 kDa. In addition, 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one] (ODQ) and cyanide inhibited formation of nitrite in A549 cells. It has been shown that ceruloplasmin (Cp) possesses an NO oxidase and nitrite synthase activity in plasma based on NO oxidation to nitrosonium cation (NO+). We observed that Cp is expressed intracellularly in lung epithelial A549 cells and secreted into medium under basal conditions and during cytokine stimulation. However, an analysis of Cp expression level and activity measured via ρ-phenylenediamine oxidase activity assay revealed very low activity compared with plasma, suggesting that there is insufficient Cp to contribute to detectable NO oxidation to nitrite in A549 cells. Additionally, Cp levels were knocked down using siRNA by more than 75% in A549 cells, with no significant change in

  10. Effect of blood nitrite and nitrate levels on murine platelet function.

    PubMed

    Park, Ji Won; Piknova, Barbora; Huang, Paul L; Noguchi, Constance T; Schechter, Alan N

    2013-01-01

    Nitric oxide (NO) appears to play an important role in the regulation of thrombosis and hemostasis by inhibiting platelet function. The discovery of NO generation by reduction of nitrite (NO₂⁻) and nitrate (NO₃⁻) in mammals has led to increased attention to these anions with respect to potential beneficial effects in cardiovascular diseases. We have previously shown that nitrite anions at 0.1 µM inhibit aggregation and activation of human platelet preparations in vitro in the presence of red blood cells and this effect was enhanced by deoxygenation, an effect likely due to NO generation. In the present study, we hypothesized that nitrite and nitrate derived from the diet could also alter platelet function upon their conversion to NO in vivo. To manipulate the levels of nitrite and nitrate in mouse blood, we used antibiotics, NOS inhibitors, low nitrite/nitrate (NOx) diets, endothelial NOS knock-out mice and also supplementation with high levels of nitrite or nitrate in the drinking water. We found that all of these perturbations affected nitrite and nitrate levels but that the lowest whole blood values were obtained by dietary restriction. Platelet aggregation and ATP release were measured in whole blood and the results show an inverse correlation between nitrite/nitrate levels and platelet activity in aggregation and ATP release. Furthermore, we demonstrated that nitrite-supplemented group has a prolonged bleeding time compared with control or low NOx diet group. These results show that diet restriction contributes greatly to blood nitrite and nitrate levels and that platelet reactivity can be significantly affected by these manipulations. Our study suggests that endogenous levels of nitrite and nitrate may be used as a biomarker for predicting platelet function and that dietary manipulation may affect thrombotic processes.

  11. Survey of nitrite content in foods from north-east China.

    PubMed

    Yuan, Y; Zhang, T; Zhuang, H; Wang, K; Zheng, Y; Zhang, H; Zhou, B; Liu, J

    2010-01-01

    This study reports a survey of nitrite in a variety of foods consumed in north-east China and estimates the intake of nitrite for the north-east Chinese consumer. A total of 642 food categories including rice and rice products, flour and flour products, soybean and products, vegetables, fruit, preserved vegetables, cured meat products, dairy products, fish products, salt, and soy sauce were analysed for their content of nitrite. Nitrite content was quite different both between different food categories and within the same food category, ranging from not determined (n.d.) to 19.7 mg kg(-1). A great variation in the content of nitrite was found for all the food products. The average content of nitrite was highest in cured meat products (14.3 mg kg(-1)). Next to that, the nitrite content was high in the order of preserved vegetables (4.1 mg kg(-1)), soybean products (3.5 mg kg(-1)), and dairy products (1.9 mg kg(-1)). The lowest average values of nitrite were detected in soy sauce, rice and rice products, salt and fish products, the contents being 0.1, 0.3, 0.3, and 0.6 mg kg(-1). Calculations on the basis of these results and including dietary surveys show that the average intake of nitrite in north-east China from food was 0.03 mg kg(-1) body weight for an average Chinese person weighing 60 kg, and the data are lower than the established acceptable daily intake (ADI) for nitrite. Cured meat products are normally the major contributor to average nitrite intake of the north-east Chinese population. The second contributor is vegetables.

  12. The effect of environmental hypercapnia and size on nitrite toxicity in the striped catfish (Pangasianodon hypophthalmus).

    PubMed

    Hvas, Malthe; Damsgaard, Christian; Gam, Le Thi Hong; Huong, Do Thi Thanh; Jensen, Frank B; Bayley, Mark

    2016-07-01

    Striped catfish (Pangasianodon hypophthalmus) are farmed intensively at high stocking densities in Vietnam where they are likely to encounter environmental hypercapnia as well as occasional high levels of aquatic nitrite. Nitrite competes with Cl(-) for uptake at the branchial HCO3(-)/Cl(-) exchanger, causing a drastic reduction in the blood oxygen carrying capacity through the formation of methaemoglobin and nitrosylhaemoglobin. Environmental hypercapnia induces a respiratory acidosis where the branchial HCO3(-)/Cl(-) exchange activity is reduced in order to retain HCO3(-) for pH recovery, which should lead to a reduced nitrite uptake. To assess the effect of hypercapnia on nitrite uptake, fish were cannulated in the dorsal aorta, allowing repeated blood sampling for measurements of haemoglobin derivatives, plasma ions and acid-base status during exposure to 0.9mM nitrite alone and in combination with acute and 48h acclimated hypercapnia over a period of 72h. Nitrite uptake was initially reduced during the hypercapnia-induced acidosis, but after pH recovery the situation was reversed, resulting in higher plasma nitrite concentrations and lower functional haemoglobin levels that eventually caused mortality. This suggests that branchial HCO3(-)/Cl(-) exchange activity is reduced only during the initial acid-base compensation, but subsequently increases with the greater availability of internal HCO3(-) counter-ions as pH is compensated. The data further suggest that branchial Na(+)/H(+) exchange plays a significant role in the initial phase of acid-base compensation. Overall, longer term environmental hypercapnia does not protect against nitrite uptake in P. hypophthalmus, but instead enhances it. In addition, we observed a significant size effect in nitrite accumulation, where large fish attained plasma [nitrite] above the ambient concentration, while small fish did not. Small P. hypophthalmus instead had significantly higher plasma [nitrate], and haemoglobin

  13. Nitrite and Nitrate Concentrations and Metabolism in Breast Milk, Infant Formula, and Parenteral Nutrition

    PubMed Central

    Jones, Jesica A.; Ninnis, Janet R.; Hopper, Andrew O.; Ibrahim, Yomna; Merritt, T. Allen; Wan, Kim-Wah; Power, Gordon G.; Blood, Arlin B.

    2015-01-01

    Dietary nitrate and nitrite are sources of gastric NO, which modulates blood flow, mucus production, and microbial flora. However, the intake and importance of these anions in infants is largely unknown. Nitrate and nitrite levels were measured in breast milk of mothers of preterm and term infants, infant formulas, and parenteral nutrition. Nitrite metabolism in breast milk was measured after freeze-thawing, at different temperatures, varying oxygen tensions, and after inhibition of potential nitrite-metabolizing enzymes. Nitrite concentrations averaged 0.07 ± 0.01 μM in milk of mothers of preterm infants, less than that of term infants (0.13 ± 0.02 μM) (P < .01). Nitrate concentrations averaged 13.6 ± 3.7 μM and 12.7 ± 4.9 μM, respectively. Nitrite and nitrate concentrations in infant formulas varied from undetectable to many-fold more than breast milk. Concentrations in parenteral nutrition were equivalent to or lower than those of breast milk. Freeze-thawing decreased nitrite concentration ∼64%, falling with a half-life of 32 minutes at 37°C. The disappearance of nitrite was oxygen-dependent and prevented by ferricyanide and 3 inhibitors of lactoperoxidase. Nitrite concentrations in breast milk decrease with storage and freeze-thawing, a decline likely mediated by lactoperoxidase. Compared to adults, infants ingest relatively little nitrite and nitrate, which may be of importance in the modulation of blood flow and the bacterial flora of the infant GI tract, especially given the protective effects of swallowed nitrite. PMID:23894175

  14. Nitrite and nitrate concentrations and metabolism in breast milk, infant formula, and parenteral nutrition.

    PubMed

    Jones, Jesica A; Ninnis, Janet R; Hopper, Andrew O; Ibrahim, Yomna; Merritt, T Allen; Wan, Kim-Wah; Power, Gordon G; Blood, Arlin B

    2014-09-01

    Dietary nitrate and nitrite are sources of gastric NO, which modulates blood flow, mucus production, and microbial flora. However, the intake and importance of these anions in infants is largely unknown. Nitrate and nitrite levels were measured in breast milk of mothers of preterm and term infants, infant formulas, and parenteral nutrition. Nitrite metabolism in breast milk was measured after freeze-thawing, at different temperatures, varying oxygen tensions, and after inhibition of potential nitrite-metabolizing enzymes. Nitrite concentrations averaged 0.07 ± 0.01 μM in milk of mothers of preterm infants, less than that of term infants (0.13 ± 0.02 μM) (P < .01). Nitrate concentrations averaged 13.6 ± 3.7 μM and 12.7 ± 4.9 μM, respectively. Nitrite and nitrate concentrations in infant formulas varied from undetectable to many-fold more than breast milk. Concentrations in parenteral nutrition were equivalent to or lower than those of breast milk. Freeze-thawing decreased nitrite concentration ~64%, falling with a half-life of 32 minutes at 37°C. The disappearance of nitrite was oxygen-dependent and prevented by ferricyanide and 3 inhibitors of lactoperoxidase. Nitrite concentrations in breast milk decrease with storage and freeze-thawing, a decline likely mediated by lactoperoxidase. Compared to adults, infants ingest relatively little nitrite and nitrate, which may be of importance in the modulation of blood flow and the bacterial flora of the infant GI tract, especially given the protective effects of swallowed nitrite.

  15. Measurement of 7-methylguanine as an estimate of the amount of dimethylnitrosamine formed following administration of aminopyrine and nitrite to rats

    SciTech Connect

    Gombar, C.T.; Zubroff, J.; Strahan, G.D.; Magee, P.N.

    1983-11-01

    A dose-related increase in the excretion of 7-(methyl-/sup 14/C)methylguanine ( (/sup 14/C)m7Gua) following p.o. administration of di(methyl-/sup 14/C)methylnitrosamine to rats. Urine was collected for 24 hr after di(methyl-/sup 14/C)methylnitrosamine administration, and the purines were precipitated from an aliquot of the urine with silver nitrate. Purines were released from the precipitate with HCl, and (/sup 14/C)m7Gua was quantified by chromatography on an Aminex A-6 column. The excretion of (/sup 14/C)m7Gua increased linearly with the dose of dimethylnitrosamine. This relationship was used to estimate the amount of di(methyl-/sup 14/C)methylnitrosamine formed in the reaction of (/sup 14/C)aminopyrine with sodium nitrite in rats gavaged with these compounds. The dose of dimethylnitrosamine was also estimated from the amount of alkylation of liver DNA in the same animals. These estimates usually differed by less than a factor of 2. (/sup 14/C)aminopyrine and sodium nitrite were administered. The possibility of using this assay to obtain data on nitrosation in humans is discussed.

  16. Photosynthetic kinetics determine the outcome of competition for dissolved inorganic carbon by freshwater microalgae: implications for acidified lakes.

    PubMed

    Williams, T G; Turpin, D H

    1987-09-01

    Photosynthetic kinetics with respect to dissolved inorganic carbon were used to predict the outcome of competition for DIC between the green alga Selenastrum minutum and the cyanobacterium Synechococcus leopoliensis at pH 6.2, 7.5, and 10. Based on measured values of the maximum rate of photosynthesis, the half-saturation value of photosynthesis with respect to DIC (K 1(2/DIC) ), and the DIC compensation point, it was predicted that S. leopoliensis would lower the steady-state DIC concentration below the DIC compensation point of S. minutum. This should result in competitive displacement of the green alga at a rate equivalent to the chemostat dilution rate. This prediction was validated by carrying out competition experiments over the range of pH. These results suggest that the low levels of DIC in air-equilibrated acidified lakes may be an important rate-limiting resource and hence affect phytoplankton community structure. Furthermore, the low levels of DIC in these systems may be below the DIC compensation point for some species, thereby precluding their growth at acid pH solely as a function of DIC limitation. The potential importance of DIC in shaping phytoplankton community structure in acidified systems is discussed.

  17. Assessment of the relationship among acidifying depositions, surface water acidification, and fish populations in North America. Volume 1. Final report

    SciTech Connect

    Marcus, M.D.; Parkhurst, B.R.; Payne, F.E.

    1983-06-01

    This report assesses the scientific understanding about relationships between acidic depositions and freshwater aquatic resources. Selected surface waters in eastern North America are becoming acidified and fish populations are being eliminated. The actual extent of these resources threatened by acidification is now known. Mostly circumstantial evidence has been compiled to suggest that long-range atmospheric transport of acidifying compounds is causing surface-water acidification in North America. Certainly, atmospheric emissions from point sources can impact localized areas. However, some data indicate that atmospheric inputs of acids from long-range transport may add little to the natural flux of acids within ecosystems. The degree of influence that atmosphere depositions can have in accelerating natural acidification rates is unknown for most potentially sensitive surface waters. Fish losses appear to result from (1) long-term accumulations of acids and metals reaching chronically toxic concentrations; and (2) short-term, episodic events causing acutely toxic acid and metal concentrations. Some impacts may be successfully mitigated through several methods. Additional research is needed to (1) identify causes of surface-water acidification; (2) develop innovative mitigation measures; (3) define mechanisms of fish loss; and (4) establish the extent of aquatic resources at risk.

  18. Effects of calcite and magnesite application to a declining Masson pine forest on strongly acidified soil in Southwestern China.

    PubMed

    Huang, Yongmei; Kang, Ronghua; Ma, Xiaoxiao; Qi, Yu; Mulder, Jan; Duan, Lei

    2014-05-15

    Liming of strongly acidified soil under a Masson pine (Pinus massoniana Lamb.) forest was studied through a seven-year field manipulation experiment at Tieshanping, Chongqing in Southwestern China. To distinguish between the individual effects of Ca(2+) and Mg(2+) addition, we separately applied calcite (CaCO3) and magnesite (MgCO3), rather than using dolomite [CaMg(CO3)2]. Both calcite and magnesite additions caused a significant increase in pH and a decrease in dissolved inorganic monomeric aluminium (Ali) concentration of soil water. Ecological recovery included increases of herb biomass (both treatments) and Mg content in Masson pine needles (magnesite treatment only). However, the growth rate of Masson pine did not increase under either treatment, possibly because of nutrient imbalance due to phosphorus (P) deficiency or limited observation period. In China, acid deposition in forest ecosystems commonly coincides with large inputs of atmogenic Ca(2+), both enhancing Mg(2+) leaching. Calcite addition may further decrease the Mg(2+) availability in soil water, thereby exacerbating Mg(2+) deficiency in the acidified forest soils of southern and southwestern China. The effect of anthropogenic acidification of naturally acid forest soils on P availability needs further study.

  19. Acrylic microspheres-based optosensor for visual detection of nitrite.

    PubMed

    Noor, Nur Syarmim Mohamed; Tan, Ling Ling; Heng, Lee Yook; Chong, Kwok Feng; Tajuddin, Saiful Nizam

    2016-09-15

    A new optosensor for visual quantitation of nitrite (NO2(-)) ion has been fabricated by physically immobilizing Safranine O (SO) reagent onto a self-adhesive poly(n-butyl acrylate) [poly(nBA)] microspheres matrix, which was synthesized via facile microemulsion UV lithography technique. Evaluation and optimization of the optical NO2(-) ion sensor was performed with a fiber optic reflectance spectrophotometer. Scanning electron micrograph showed well-shaped and smooth spherical morphology of the poly(nBA) microspheres with a narrow particles size distribution from 0.6 μm up to 1.8 μm. The uniform size distribution of the acrylic microspheres promoted homogeneity of the immobilized SO reagent molecules on the microspheres' surfaces, thereby enhanced the sensing response reproducibility (<5% RSD) with a linear range obtained from 10 to 100 ppm NO2(-) ion. The micro-sized acrylic immobilization matrix demonstrated no significant barrier for diffusion of reactant and product, and served as a good solid state ion transport medium for reflectometric nitrite determination in food samples.

  20. Control of the ambident reactivity of the nitrite ion.

    PubMed

    Dong, Hai; Rahm, Martin; Thota, Niranjan; Deng, Lingquan; Brinck, Tore; Ramström, Olof

    2013-01-28

    In previous studies, it was reported that a neighbouring equatorial ester group is essential for a good yield of nitrite-mediated triflate inversion, whereas with neighbouring benzyl ether groups or axial ester groups, mixtures are generally produced. In the present study, the origin of this difference was addressed. The ambident reactivity of the nitrite ion has been found to be the cause of the complex product formation observed, which can be controlled by a neighbouring equatorial ester group. Both N-attack and O-attack occur in the absence of the ester group, whereas O-attack is favoured in its presence. A neighbouring group assistance mechanism is proposed, in addition to steric effects, based on secondary interactions between the neighbouring ester group and the incoming nucleophile. High-level quantum mechanical calculations were carried out in order to delineate this effect. The theoretical results are in excellent agreement with experiments, and suggest a catalytic role for the neighbouring equatorial ester group.