• This research investigated spatial-temporal variation in benthic bacterial community structure, rates of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) processes and abundances of corresponding genes and transcripts at three sites-the estuary-head, mid-estuary and the estuary mouth (EM) along the nitrate gradient of the Colne estuary over an annual cycle. (gla.ac.uk)
  • Abundance of gene markers for nitrate-reduction (nitrate reductase narG and napA), denitrification (nitrite reductase nirS) and DNRA (DNRA nitrite reductase nrfA) declined along the estuary with significant relationships between denitrification and nirS abundance, and DNRA and nrfA abundance. (gla.ac.uk)
  • The concentrations of nitrate and nitrite were underdetection line, indicating that the nitrate was used by denitrification or the potential dissimilatory reduction. (cje.net.cn)
  • In addition to denitrification, respiratory nitrate ammonification (also termed dissimilatory nitrate reduction to ammonium) is another important nitrate-reducing mechanism in soil, responsible for the loss of nitrate and production of N2O from reduction of NO that is formed as a by-product of the reduction process. (uea.ac.uk)
  • Hence, as a first step to better understand the interplay between denitrification, DNRA and reduction of nitrate to nitrite in estuarine sediments, nitrogen reduction potentials were determined in sediments of the Paulina polder mudflat (Westerschelde estuary). (genome-mining.cn)
  • Denitrification occurred at all sites, DNRA was either the dominant process (two out of five sites) or absent, while nitrate reduction to nitrite was observed in most sites but never dominant. (genome-mining.cn)
  • Therefore, low ratio would decrease competition for nitrite between ANAMMOX and denitrification, which was favorable for reducing the negative effect of organic COD on ANAMMOX. (engineering.org.cn)
  • Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. (essex.ac.uk)
  • Dimethyl sulfoxide (DMSO) and fumarate reductase gene expression was down-regulated at least 2-fold in the mutant, which, showed lower or no reduction of these electron acceptors when compared to the wild type, suggesting both respiratory pathways are under EtrA control. (biomedcentral.com)
  • Fields with low C : N ratio had an overrepresentation of genes for carbon degradation, carbon fixation, metal reductase, and organic remediation categories, while fields with high C : N ratio had an overrepresentation of genes encoding dissimilatory sulfate reductase, methane oxidation, nitrification, and nitrogen fixation. (hindawi.com)
  • The oxidation of ammonium is a key step in the nitrogen cycle, regulating the production of nitrate, nitrous oxide and dinitrogen. (nature.com)
  • We observed high variability in dominant nitrogen removing processes over a short distance (1.6 m), with nitrous oxide, ammonium and nitrite production rates differing significantly between all sampling sites. (genome-mining.cn)
  • A two-year lysimeter study was undertaken to compare the environmental effects (e.g. nitrate leaching and nitrous oxide emissions) of soil applied lactose-depleted dairy factory effluent (LD-DFE) with lactose-rich DFE. (5doc.co)
  • Other nitrate decomposers can further convert nitrate to nitrous oxide (NO) or nitrogen gas (N 2 ). (researchtweet.com)
  • Dissimilatory nitrate reduction to ammonium (DNRA), which theoretically improves nitrogen retention in soils, has been suggested as a microbial process that may be harnessed, especially since many DNRA-catalyzing organisms have been found to possess nosZ genes and the ability to respire N2O. (bvsalud.org)
  • IMPORTANCE Dissimilatory nitrate/nitrite reduction to ammonium (DNRA) is a microbial energy-conserving process that reduces NO3- and/or NO2- to NH4+. (bvsalud.org)
  • However, recent reports on the contribution of dissimilatory nitrate reduction to ammonium (DNRA) to nitrogen removal in these systems indicated a similar or higher importance, although the ratio between both processes remains ambiguous. (genome-mining.cn)
  • In addition, novel nitrate-to-ammonium reducers assigned to Thalassospira, Celeribacter, and Halomonas, for which DNRA was thus far unreported, were isolated, with DNRA phenotype reconfirmed through nrfA gene amplification. (genome-mining.cn)
  • This study demonstrates high small scale heterogeneity among dissimilatory nitrate reduction processes in estuarine sediments and provides novel marine DNRA organisms that represent valuable alternatives to the current model organisms. (genome-mining.cn)
  • Lake sediments generally have a unique reduction environment with complicated biogeochemical processes of nitrogen. (cje.net.cn)
  • Dalsgaard, T. & Thamdrup, B. Factors controlling anaerobic ammonium oxidation with nitrite in marine sediments. (nature.com)
  • Nitrate Reduction Functional Genes and Nitrate Reduction Potentials Persist in Deeper Estuarine Sediments. (essex.ac.uk)
  • Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. (essex.ac.uk)
  • Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. (essex.ac.uk)
  • Since some of the aggregate-forming diatom species store nitrate intracellularly, we explored the fate of intracellular nitrate and its availability for microbial metabolism within anoxic diatom-bacteria aggregates. (frontiersin.org)
  • The ubiquitous nitrate-storing diatom Skeletonema marinoi was studied as both axenic cultures and laboratory-produced diatom-bacteria aggregates. (frontiersin.org)
  • Intracellular nitrate was used up within 2-3 days after shifting diatom-bacteria aggregates to dark and anoxic conditions. (frontiersin.org)
  • The capability to oxidize sulfide and store sulfur are the main features which separates Beggiatoa and closely related Thioploca as filamentous colorless sulfur bacteria from other filamentous bacteria (like cyanobacteria and the nonsulfur-oxidizing Cytophaga and Flexibacter) Another defining feature is the ability to store nitrate inside the vacuoles of the wide marine species' cells. (wikipedia.org)
  • In ammonia-oxidizing bacteria, N2O is formed through the oxidation of hydroxylamine to nitrite. (uea.ac.uk)
  • This review will synthesize our current understand- ing of the environmental, regulatory and biochemical control of N2O emissions by nitrate-reducing bacteria and point to new solutions for agricultural GHG mitigation. (uea.ac.uk)
  • An enzyme found primarily in BACTERIA and FUNGI that catalyzes the oxidation of ammonium hydroxide to nitrite. (lookformedical.com)
  • Nitrate reduction process generally mediated by anaerobic bacteria by which nitrogen available to plants is converted to a gaseous form and lost from the soil or water column. (lookformedical.com)
  • However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. (essex.ac.uk)
  • Aerobic nitrification primarily occurs through the activities of ammonia-oxidising bacteria and archaea, nitrite-oxidising bacteria, and complete ammonia-oxidising (comammox) bacteria adapted to these environments. (microbial-ecology.de)
  • Optical mapping showed that the genome size was about 7.4 Mb and the sequence analyses detected pathways for sulfur oxidation, nitrate and oxygen respiration, and CO2 fixation, confirming the chemolithoautotrophic physiology of Beggiatoa. (wikipedia.org)
  • Genome annotation suggested that the reverse hydroxylamine ubiquinone redox module (rHURM) may be used for anaerobic cellular respiration in N. profundicola when nitrate is the terminal electron acceptor. (udel.edu)
  • Stable 15 N isotope incubations under dark and anoxic conditions revealed that axenic S. marinoi is able to reduce intracellular nitrate to ammonium that is immediately excreted by the cells. (frontiersin.org)
  • Intracellular nitrate concentrations exceeded extracellular concentrations by three orders of magnitude. (frontiersin.org)
  • Thirty-one percent of the diatom-derived nitrate was converted to nitrogen gas, indicating that a substantial fraction of the intracellular nitrate pool of S. marinoi becomes available to the aggregate-associated bacterial community. (frontiersin.org)
  • Only 5% of the intracellular nitrate was reduced to ammonium, while 59% was recovered as nitrite. (frontiersin.org)
  • Additionally, it may be expected that intracellular nitrate not converted before the aggregates have settled onto the seafloor could fuel benthic nitrogen transformations. (frontiersin.org)
  • We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. (essex.ac.uk)
  • Hence, aggregate-associated diatoms accumulate nitrate from the surrounding water and sustain complex nitrogen transformations, including loss of fixed nitrogen, in anoxic, pelagic microniches. (frontiersin.org)
  • We detected Mars-relevant metabolisms including hydrogenotrophic sulfate reduction, sulfur reduction, and sulfide oxidation, which indicate the potential for microbial life in analogous S-rich brines on past and present Mars. (biomedcentral.com)
  • The estuarine nitrogen cycle can be substantially altered due to anthropogenic activities resulting in increased amounts of inorganic nitrogen (mainly nitrate). (genome-mining.cn)
  • The inorganic nitrites of the type MNO2 (where M=metal) are all insoluble, except the alkali nitrites. (lookformedical.com)
  • Sulphate ion (SO 4 -2 ), nitrate (NO 3 - ), and ferric ion (Fe 3+ ) are examples of inorganic compounds. (researchtweet.com)
  • In denitrifiers, nitrate is reduced to N2 via nitrite, NO and N2O production. (uea.ac.uk)
  • The proposed rHURM pathway includes rHaoA and hcp/har which catalyze the reduction of nitrite to hydroxylamine, as an intermediate, and hydroxylamine to ammonium, respectively. (udel.edu)
  • The four nitrogen compounds in the proposed pathway were measured in the substrate addition assays-nitrate, nitrite, hydroxylamine, and ammonium. (udel.edu)
  • Hydroxylamine was present in small concentrations during nitrate reduction to ammonium. (udel.edu)
  • The results presented here are consistent with hydroxylamine as a free intermediate in nitrate reduction to ammonium in N. profundicola. (udel.edu)
  • Here, we incubate tropical upland soil slurries with isotopically labelled ammonium and iron( iii ) to assess the potential for anaerobic ammonium oxidation coupled to iron( iii ) reduction, otherwise known as Feammox 6 , in these soils. (nature.com)
  • For over two decades, sulfate reduction with ammonium oxidation (SRAO) had been reported from laboratory experiments. (engineering.org.cn)
  • Sulfate reduction was dominated by hydrogen-oxidizing chemolithoautotrophic Desulfovibrionaceae sp. (biomedcentral.com)
  • In this study, cell growth was monitored in batch cultures under varied concentrations of sulfide, nitrate, formate, and H2. (udel.edu)
  • Heterotrophic sulfate reduction mainly contributed to sulfate conversion. (engineering.org.cn)
  • Results obtained differed largely for the conversion mole ratios (ammonium/sulfate), and even the intermediate and final products of sulfate reduction. (engineering.org.cn)
  • and was identified in phyla not typically associated with sulfate reduction in novel lineages of Spirochaetota and Bacteroidota . (biomedcentral.com)
  • N. profundicola was isolated with polysulfide as the electron acceptor for respiratory growth, but is also able to utilize nitrate as an electron acceptor for growth. (udel.edu)
  • Sulphate reduction employs sulphate (SO 4 -2 ) as a final electron receptor, resulting in the metabolic end product hydrogen sulphide (H 2 S). (researchtweet.com)
  • Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. (essex.ac.uk)
  • Deep lakes experience alternate oxidation and reduction environment, which mayaffect the biogeochemical processes of nitrogen. (cje.net.cn)
  • We show that Feammox can produce dinitrogen, nitrite or nitrate in tropical upland soils. (nature.com)
  • In soil samples with 1% BC, a reduction of over 90% in the total concentration of PAH in the leached water was observed. (univie.ac.at)
  • Additional experiments including in vitro assays of enzymatic activity and gene disruption will be required to fully address the role of the proposed rHURM pathway in nitrate reduction. (udel.edu)
  • The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the sediment column. (essex.ac.uk)
  • Contamination of wastewater with organic-limited nitrates has become an urgent problem in wastewater treatment. (mdpi.com)
  • Interestingly, the N. profundicola genome lacks homologs of known enzymes used in nitrite reduction. (udel.edu)
  • The NO2--to-NH4+ reduction following oxic-to-anoxic transition was significantly delayed in NosZ-inhibited C2H2-amended cultures, and the inhibition was more pronounced with repeated oxic-anoxic transitions. (bvsalud.org)
  • Comparing to the control, nitrate content increased 38.75 % at the end of the compost. (researchsquare.com)
  • Vast expanses of oxygen-deficient and nitrite-rich water define the major oxygen minimum zones (OMZs) of the global ocean. (sek-stolarstwo.pl)
  • The results suggested that the increases of NH 4 + -N concentration in pore water may be related to the dissimilatory reduction process. (cje.net.cn)
  • Naqvi, 1991, Naqvi, 1994) suggests that average secondary nitrite maximum values are ⩾1 μM. (sek-stolarstwo.pl)
  • Larger marine strains, with vacuoles for nitrate storing (filaments' diameter vary between 5 and 140 µm) Obviously, this classification is purely ideal so some exceptions can exist. (wikipedia.org)
  • however, limited anaerobic growth and nitrate reduction occurred, suggesting that multiple regulators control nitrate reduction in this strain. (biomedcentral.com)
  • Kinetics of dissimilatory nitrate and nitrite reduction in suspended growth culture. (tci-thaijo.org)
  • The range of nitrate-N leaching loss from LD-DFE plus urine is no different from the lactose-rich DFE nitrate leaching loss. (5doc.co)