DISSIMILATORY REDUCTION OF 15N-LABELED NITRATE IN THE PRESENCE OF NONLABELED NO OR N2O

1984 ◽  
Vol 64 (1) ◽  
pp. 21-29 ◽  
Author(s):  
H. NÔMMIK ◽  
J. MELIN ◽  
D. J. PLUTH
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Isotopic Composition ◽  
Key Words ◽  
Nitrate Reduction ◽  
Isotopic Exchange ◽  
No Reduction ◽  
Nitrate Concentration ◽  
Anaerobic Incubation ◽  
Lag Period

Dissimilatory reduction of labeled nitrate in the presence of nonlabeled N2O, or NO, was studied in forest mor humus during anaerobic incubation. Data on the isotopic composition of the N2O and N2 pools suggested that all of the N2 formed had passed the N2O pool. This finding supported the earlier suggestion that N2O is an obligatory intermediate in the dissimilatory reduction of nitrate to N2. Due to a likely occurrence of nonenzymatic isotopic exchange between NO and nitrate, the technique used was considered unreliable to study the nature of NO as a possible intermediate in the sequence of nitrate reduction. However, qualitative observations indicated that NO was not a free, obligatory intermediate. Reduction of nitrate was strongly inhibited by the presence of NO. Reduction of N2O to N2 was significantly retarded by the presence of nitrate. The length of the lag period increased as the initial nitrate concentration was increased. Key words: Dissimilatory nitrate reduction, denitrification, nitrous oxide, nitric oxide

A Cr-phthalocyanine monolayer as a potential catalyst for NO reduction investigated by DFT calculations

RSC Advances ◽  
2016 ◽  
Vol 6 (25) ◽  
pp. 20500-20506 ◽  
Author(s):  
Jittima Meeprasert ◽  
Anchalee Junkaew ◽  
Nawee Kungwan ◽  
Bavornpon Jansang ◽  
Supawadee Namuangruk
Keyword(s):  
Nitric Oxide ◽  
Density Functional Theory ◽  
Nitrous Oxide ◽  
Reaction Mechanism ◽  
Dft Calculations ◽  
Density Functional ◽  
No Reduction ◽  
Functional Theory

The reaction mechanism of nitric oxide (NO) reduction to nitrous oxide (N2O) and N2 catalyzed by Cr-phthalocyanine sheet (CrPc) was investigated using periodic density functional theory (DFT).

Effect of didecyl dimethyl ammonium chloride on nitrate reduction in a mixed methanogenic culture

2008 ◽  
Vol 57 (4) ◽  
pp. 541-546 ◽  
Author(s):  
U. Tezel ◽  
S. G. Pavlostathis ◽  
J. A. Pierson
Keyword(s):  
Nitrous Oxide ◽  
Ammonium Chloride ◽  
Nitrate Reduction ◽  
Microbial Growth ◽  
Volatile Fatty Acids ◽  
Nitrate Concentration ◽  
Ammonium Compound ◽  
Dimethyl Ammonium Chloride ◽  
Dimethyl Ammonium

The effect of the quaternary ammonium compound, didecyl dimethyl ammonium chloride (DDAC), on nitrate reduction was investigated at concentrations up to 100 mg/L in a batch assay using a mixed, mesophilic (35°C) methanogenic culture. Glucose was used as the carbon and energy source and the initial nitrate concentration was 70 mg N/L. Dissimilatory nitrate reduction to ammonia (DNRA) and to dinitrogen (denitrification) were observed at DDAC concentrations up to 25 mg/L. At and above 50 mg DDAC/L, DNRA was inhibited and denitrification was incomplete resulting in accumulation of nitrous oxide. At DDAC concentrations above 10 mg/L, production of nitrous oxide, even transiently, resulted in complete, long-term inhibition of methanogenesis and accumulation of volatile fatty acids. Fermentation was inhibited at and above 75 mg DDAC/L. DDAC suppressed microbial growth and caused cell lysis at a concentration 50 mg/L or higher. Most of the added DDAC was adsorbed on the biomass. Over 96% of the added DDAC was recovered from all cultures at the end of the 100-days incubation period, indicating that DDAC did not degrade in the mixed methanogenic culture under the conditions of this study.

Emissions of nitrous oxide and nitric oxide associated with the decomposition of arable crop residues on a sandy loam soil in Eastern England

Agronomie ◽  
2002 ◽  
Vol 22 (7-8) ◽  
pp. 731-738 ◽  
Author(s):  
Roland Harrison ◽  
Sharon Ellis ◽  
Roy Cross ◽  
James Harrison Hodgson
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Crop Residues ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Arable Crop ◽  
Loam Soil

A flat-lying dimer as a key intermediate in NO reduction on Cu(100)

2021 ◽  
Author(s):  
Kenta Kuroishi ◽  
Muhammad Rifqi Al Fauzan ◽  
Ngoc Thanh Pham ◽  
Yuelin Wang ◽  
Yuji Hamamoto ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Density Functional Theory ◽  
Scanning Tunneling Microscope ◽  
Density Functional ◽  
No Reduction ◽  
Density Functional Theory Calculations ◽  
Scanning Tunneling ◽  
Functional Theory ◽  
Tunneling Microscope ◽  
Electron Energy Loss

The reaction of nitric oxide (NO) on Cu(100) is studied by scanning tunneling microscope, electron energy loss spectroscopy and density functional theory calculations. The NO molecules adsorb mainly as monomers...

Molybdenum incorporation in denitrifying Azospirillum brasilense Sp7

1992 ◽  
Vol 38 (10) ◽  
pp. 1042-1047 ◽  
Author(s):  
Christian Chauret ◽  
Wilfredo L. Barraquio ◽  
Roger Knowles
Keyword(s):  
Nitrate Reductase ◽  
Key Words ◽  
Nitrate Reduction ◽  
Gel Electrophoresis ◽  
Azospirillum Brasilense ◽  
Paracoccus Denitrificans ◽  
Free Medium ◽  
Azospirillum Brasilense Sp7

Nondenaturating disc gel electrophoresis revealed that 99Mo was incorporated into the nitrate reductase of Azospirillum brasilense grown in the absence but not in the presence of tungstate. Under denitrifying conditions, A. brasilense grown in tungsten-free medium steadily accumulated 99Mo for 12 h. In contrast, Paracoccus denitrificans grown under the same conditions ceased uptake after 1 h. However, both bacteria were incapable of accumulating significant amounts of 99Mo in media containing 10 mM tungstate, even though nitrate was reduced by A. brasilense. Aerobically grown A. brasilense cells transported 99Mo more efficiently than anaerobically grown cells. Key words: Azospirillum brasilense, tungsten, molybdenum incorporation, nitrate reduction.

The complete denitrification pathway of the symbiotic, nitrogen-fixing bacterium Bradyrhizobium japonicum

2005 ◽  
Vol 33 (1) ◽  
pp. 141-144 ◽  
Author(s):  
E.J. Bedmar ◽  
E.F. Robles ◽  
M.J. Delgado
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Bradyrhizobium Japonicum ◽  
Mutational Analysis ◽  
Control Level ◽  
Gene Clusters ◽  
Alternative Form ◽  
Nitrate Respiration ◽  
Regulatory Cascade ◽  
Denitrification Genes

Denitrification is an alternative form of respiration in which bacteria sequentially reduce nitrate or nitrite to nitrogen gas by the intermediates nitric oxide and nitrous oxide when oxygen concentrations are limiting. In Bradyrhizobium japonicum, the N2-fixing microsymbiont of soya beans, denitrification depends on the napEDABC, nirK, norCBQD, and nosRZDFYLX gene clusters encoding nitrate-, nitrite-, nitric oxide- and nitrous oxide-reductase respectively. Mutational analysis of the B. japonicum nap genes has demonstrated that the periplasmic nitrate reductase is the only enzyme responsible for nitrate respiration in this bacterium. Regulatory studies using transcriptional lacZ fusions to the nirK, norCBQD and nosRZDFYLX promoter region indicated that microaerobic induction of these promoters is dependent on the fixLJ and fixK2 genes whose products form the FixLJ–FixK2 regulatory cascade. Besides FixK2, another protein, nitrite and nitric oxide respiratory regulator, has been shown to be required for N-oxide regulation of the B. japonicum nirK and norCBQD genes. Thus nitrite and nitric oxide respiratory regulator adds to the FixLJ–FixK2 cascade an additional control level which integrates the N-oxide signal that is critical for maximal induction of the B. japonicum denitrification genes. However, the identity of the signalling molecule and the sensing mechanism remains unknown.

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