The calibration of the intramolecular nitrogen isotope distribution in nitrous oxide measured by isotope ratio mass spectrometry.

PubMed

Westley, Marian B; Popp, Brian N; Rust, Terri M

2007-01-01

Two alternative approaches for the calibration of the intramolecular nitrogen isotope distribution in nitrous oxide using isotope ratio mass spectrometry have yielded a difference in the 15N site preference (defined as the difference between the delta15N of the central and end position nitrogen in NNO) of tropospheric N2O of almost 30 per thousand. One approach is based on adding small amounts of labeled 15N2O to the N2O reference gas and tracking the subsequent changes in m/z 30, 31, 44, 45 and 46, and this yields a 15N site preference of 46.3 +/- 1.4 per thousand for tropospheric N2O. The other involves the synthesis of N2O by thermal decomposition of isotopically characterized ammonium nitrate and yields a 15N site preference of 18.7 +/- 2.2 per thousand for tropospheric N2O. Both approaches neglect to fully account for isotope effects associated with the formation of NO+ fragment ions from the different isotopic species of N2O in the ion source of a mass spectrometer. These effects vary with conditions in the ion source and make it impossible to reproduce a calibration based on the addition of isotopically enriched N2O on mass spectrometers with different ion source configurations. These effects have a much smaller impact on the comparison of a laboratory reference gas with N2O synthesized from isotopically characterized ammonium nitrate. This second approach was successfully replicated and leads us to advocate the acceptance of the site preference value 18.7 +/- 2.2 per thousand for tropospheric N2O as the provisional community standard until further independent calibrations are developed and validated. We present a technique for evaluating the isotope effects associated with fragment ion formation and revised equations for converting ion signal ratios into isotopomer ratios. Copyright 2007 John Wiley & Sons, Ltd.

A nitrogen response pathway regulates virulence functions in Fusarium oxysporum via the protein kinase TOR and the bZIP protein MeaB.

PubMed

López-Berges, Manuel S; Rispail, Nicolas; Prados-Rosales, Rafael C; Di Pietro, Antonio

2010-07-01

During infection, fungal pathogens activate virulence mechanisms, such as host adhesion, penetration and invasive growth. In the vascular wilt fungus Fusarium oxysporum, the mitogen-activated protein kinase Fmk1 is required for plant infection and controls processes such as cellophane penetration, vegetative hyphal fusion, or root adhesion. Here, we show that these virulence-related functions are repressed by the preferred nitrogen source ammonium and restored by treatment with l-methionine sulfoximine or rapamycin, two specific inhibitors of Gln synthetase and the protein kinase TOR, respectively. Deletion of the bZIP protein MeaB also resulted in nitrogen source-independent activation of virulence mechanisms. Activation of these functions did not require the global nitrogen regulator AreA, suggesting that MeaB-mediated repression of virulence functions does not act through inhibition of AreA. Tomato plants (Solanum lycopersicum) supplied with ammonium rather than nitrate showed a significant reduction in vascular wilt symptoms when infected with the wild type but not with the DeltameaB strain. Nitrogen source also affected invasive growth in the rice blast fungus Magnaporthe oryzae and the wheat head blight pathogen Fusarium graminearum. We propose that a conserved nitrogen-responsive pathway might operate via TOR and MeaB to control virulence in plant pathogenic fungi.

Apparatus for the production of boron nitride nanotubes

DOEpatents

Smith, Michael W; Jordan, Kevin

2014-06-17

An apparatus for the large scale production of boron nitride nanotubes comprising; a pressure chamber containing; a continuously fed boron containing target; a source of thermal energy preferably a focused laser beam; a cooled condenser; a source of pressurized nitrogen gas; and a mechanism for extracting boron nitride nanotubes that are condensed on or in the area of the cooled condenser from the pressure chamber.

A carnivorous sundew plant prefers protein over chitin as a source of nitrogen from its traps.

PubMed

Pavlovič, Andrej; Krausko, Miroslav; Adamec, Lubomír

2016-07-01

Carnivorous plants have evolved in nutrient-poor wetland habitats. They capture arthropod prey, which is an additional source of plant growth limiting nutrients. One of them is nitrogen, which occurs in the form of chitin and proteins in prey carcasses. In this study, the nutritional value of chitin and protein and their digestion traits in the carnivorous sundew Drosera capensis L. were estimated using stable nitrogen isotope abundance. Plants fed on chitin derived 49% of the leaf nitrogen from chitin, while those fed on the protein bovine serum albumin (BSA) derived 70% of its leaf nitrogen from this. Moreover, leaf nitrogen content doubled in protein-fed in comparison to chitin-fed plants indicating that the proteins were digested more effectively in comparison to chitin and resulted in significantly higher chlorophyll contents. The surplus chlorophyll and absorbed nitrogen from the protein digestion were incorporated into photosynthetic proteins - the light harvesting antennae of photosystem II. The incorporation of insect nitrogen into the plant photosynthetic apparatus may explain the increased rate of photosynthesis and plant growth after feeding. This general response in many genera of carnivorous plants has been reported in many previous studies. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

The Crc protein inhibits the production of polyhydroxyalkanoates in Pseudomonas putida under balanced carbon/nitrogen growth conditions.

PubMed

La Rosa, Ruggero; de la Peña, Fernando; Prieto, María Axiliadora; Rojo, Fernando

2014-01-01

Pseudomonas putida synthesizes polyhydroxyalkanoates (PHAs) as storage compounds. PHA synthesis is more active when the carbon source is in excess and the nitrogen source is limiting, but can also occur at a lower rate under balanced carbon/nitrogen ratios. This work shows that PHA synthesis is controlled by the Crc global regulator, a protein that optimizes carbon metabolism by inhibiting the expression of genes involved in the use of non-preferred carbon sources. Crc acts post-transcriptionally. The mRNAs of target genes contain characteristic catabolite activity (CA) motifs near the ribosome binding site. Sequences resembling CA motifs can be predicted for the phaC1 gene, which codes for a PHA polymerase, and for phaI and phaF, which encode proteins associated to PHA granules. Our results show that Crc inhibits the translation of phaC1 mRNA, but not that of phaI or phaF, reducing the amount of PHA accumulated in the cell. Crc inhibited PHA synthesis during exponential growth in media containing a balanced carbon/nitrogen ratio. No inhibition was seen when the carbon/nitrogen ratio was imbalanced. This extends the role of Crc beyond that of controlling the hierarchical utilization of carbon sources and provides a link between PHA synthesis and the global regulatory networks controlling carbon flow. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Framework for community functioning: synthesis of stress gradient and resource partitioning concepts

PubMed Central

2017-01-01

To understand how communities function and generate abundance, I develop a framework integrating elements from the stress gradient and resource partitioning concepts. The framework suggests that guild abundance depends on environmental and spatial factors but also on inter-guild interactions (competitor or facilitator richness), which can alter the fundamental niche of constituent species in negative (competition) or positive direction (facilitation). Consequently, the environmental and spatial mechanisms driving guild abundance would differ across guilds and interaction modes. Using continental data on stream diatoms and physico-chemistry, the roles of these mechanisms were tested under three interaction modes—shared preference, distinct preference, and facilitative, whereby pairs of guilds exhibited, respectively, a dominance-tolerance tradeoff along a eutrophication gradient, specialization along a pH gradient, or a donor-recipient relationship along a nitrogen gradient. Representative of the shared preference mode were the motile (dominant) and low profile (tolerant) guilds, of the distinct preference mode—the acidophilous and alkaliphilous (low profile) guilds, and of the facilitative mode—nitrogen fixers (donors) and motile species (recipients). In each mode, the influences of environment, space (latitude and longitude), and competitor or facilitator richness on guild density were assessed by variance partitioning. Pure environment constrained most strongly the density of the dominant, the acidophilous, and the recipient guild in the shared preference, distinct preference, and facilitative mode, respectively, while spatial effects were important only for the low profile guild. Higher competitor richness was associated with lower density of the tolerant guild in the shared preference mode, both guilds in the distinct preference mode, and the donor guild in the facilitative mode. Conversely, recipient density in the facilitative mode increased with donor richness in stressful nitrogen-poor environments. Thus, diatom guild abundance patterns were determined primarily by biotic and/or environmental impacts and, with the exception of the low profile guild, were insensitive to spatial effects. This framework identifies major sources of variability in diatom guild abundance with implications for the understanding of biodiversity-ecosystem functioning. PMID:29018618

Dynamics of the Escherichia coli proteome in response to nitrogen starvation and entry into the stationary phase.

PubMed

Sanchuki, Heloisa B S; Gravina, Fernanda; Rodrigues, Thiago E; Gerhardt, Edileusa C M; Pedrosa, Fábio O; Souza, Emanuel M; Raittz, Roberto T; Valdameri, Glaucio; de Souza, Gustavo A; Huergo, Luciano F

2017-03-01

Nitrogen is needed for the biosynthesis of biomolecules including proteins and nucleic acids. In the absence of fixed nitrogen prokaryotes such as E. coli immediately ceases growth. Ammonium is the preferred nitrogen source for E. coli supporting the fastest growth rates. Under conditions of ammonium limitation, E. coli can use alternative nitrogen sources to supply ammonium ions and this reprogramming is led by the induction of the NtrC regulon. Here we used label free proteomics to determine the dynamics of E. coli proteins expression in response to ammonium starvation in both the short (30min) and the longer (60min) starvation. Protein abundances and post-translational modifications confirmed that activation of the NtrC regulon acts as the first line of defense against nitrogen starvation. The ribosome inactivating protein Rmf was induced shortly after ammonium exhaustion and this was preceded by induction of other ribosome inactivating proteins such as Hpf and RaiA supporting the hypothesis that ribosome shut-down is a key process during nitrogen limitation stress. The proteomic data revealed that growth arrest due to nitrogen starvation correlates with the accumulation of proteins involved in DNA condensation, RNA and protein catabolism and ribosome hibernation. Collectively, these proteome adaptations will result in metabolic inactive cells which are likely to exhibit multidrug tolerance. Copyright © 2016 Elsevier B.V. All rights reserved.

Nutrient content of some winter grouse foods

USGS Publications Warehouse

Treichler, R.R.; Stow, R.W.; Nelson, A.L.

1946-01-01

Seventeen preferred grouse foods were collected during the late winter and analyzed for nutrient content. The results include moisture, crude protein, ether extract, crude fiber, nitrogenfree extract, ash, calcium, phosphorus, and gross energy content expressed both on moisture free and fresh bases.....The preferred winter foods of grouse are characterized by a high content of dry substance and of nitrogen-free extract......On the basis of nutrient content, the foods examined are well qualified as sources of energy and other essential nutrients required for maintenance of grouse during the winter season.

Drought stress obliterates the preference for ammonium as an N source in the C4 plant Spartina alterniflora.

PubMed

Hessini, Kamel; Kronzucker, Herbert J; Abdelly, Chedly; Cruz, Cristina

2017-06-01

The C 4 grass Spartina alterniflora is known for its unique salt tolerance and strong preference for ammonium (NH 4 + ) as a nitrogen (N) source. We here examined whether Spartina's unique preference for NH 4 + results in improved performance under drought stress. Manipulative greenhouse experiments were carried out to measure the effects of variable water availability and inorganic N sources on plant performance (growth, photosynthesis, antioxidant, and N metabolism). Drought strongly reduced leaf number and area, plant fresh and dry weight, and photosynthetic activity on all N sources, but the reduction was most pronounced on NH 4 + . Indeed, the growth advantage seen on NH 4 + in the absence of drought, producing nearly double the biomass compared to growth on NO 3 - , was entirely obliterated under both intermediate and severe drought conditions (50 and 25% field capacity, respectively). Both fresh and dry weight became indistinguishable among N sources under drought. Major markers of the antioxidant capacity of the plant, the activities of the enzymes superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, showed higher constitutive levels on NH 4 + . Catalase and glutathione reductase were specifically upregulated in NH 4 + -fed plants with increasing drought stress. This upregulation, however, failed to protect the plants from drought stress. Nitrogen metabolism was characterized by lower constitutive levels of glutamine synthetase in NH 4 + -fed plants, and a rise in glutamate dehydrogenase (GDH) activity under drought, accompanied by elevated proline levels in leaves. Our results support postulates on the important role of GDH induction, and its involvement in the synthesis of compatible solutes, under abiotic stress. We show that, despite this metabolic shift, S. alterniflora's sensitivity to drought does not benefit from growth on NH 4 + and that the imposition of drought stress equalizes all N-source-related growth differences observed under non-drought conditions. Copyright © 2017 Elsevier GmbH. All rights reserved.

Specific phenotypic traits of Starmerella bacillaris regarding nitrogen source consumption and central carbon metabolites production during wine fermentation.

PubMed

Englezos, Vasileios; Cocolin, Luca; Rantsiou, Kalliopi; Ortiz-Julien, Anne; Bloem, Audrey; Dequin, Sylvie; Camarasa, Carole

2018-06-01

Over the last past years, the potential of non-Saccharomyces yeasts to improve the sensory quality of wine has been well recognized. In particular, the use of Starmerella bacillaris in mixed fermentations with Saccharomyces cerevisiae was reported as an appropriate way to enhance glycerol formation and reduce ethanol production. However, during sequential fermentation, many factors as the inoculation timing, strain combination and physical and biochemical interactions can affect yeast growth, fermentation process and/or metabolite synthesis. Among them, yeast assimilable nitrogen (YAN) availability, due to its role in the control of growth and fermentation, has been identified as a key parameter. Consequently, a comprehensive understanding of the metabolic specificities and the nitrogen requirements would be valuable to better exploit the potential of Starm. bacillaris during wine fermentation. In this study, marked differences in the consumption of the total and individual nitrogen sources were registered between the two species, while the two Starm. bacillaris strains generally behaved uniformly. Starm. bacillaris strains are differentiated by their preferential uptake of ammonium compared with amino acids that are poorly assimilated or even produced (alanine). Otherwise, the non- Saccharomyces yeast exhibits low activity through the acetaldehyde pathway, which triggers an important redistribution of fluxes through the central carbon metabolic network. In particular, the formation of metabolites deriving from the two glycolytic intermediates glyceraldehyde-3-phosphate and pyruvate is substantially increased during fermentations by Starm. bacillaris This knowledge will be useful to better control the fermentation process in mixed fermentation with Starm. bacillaris and S. cerevisiae IMPORTANCE Mixed fermentations using a controlled inoculation of Starm. bacillaris and S. cerevisiae starter cultures represent a feasible way to modulate wine composition that takes advantage of both the phenotypic specificities of the non- Saccharomyces strain and the ability of S. cerevisiae to complete wine fermentation. However, according to the composition of grape juices, the consumption by Starm. bacillaris of nutrients, in particular of nitrogen sources, during the first stages of the process may result in depletions that further limit the growth of S. cerevisiae and lead to stuck or sluggish fermentations. Consequently, understanding the preferences of non- Saccharomyces yeasts for the nitrogen sources available in grape must together with their phenotypic specificities is essential for an efficient implementation of sequential wine fermentations with Starm. bacillaris and S. cerevisiae species. The results of our studies demonstrate a clear preference for ammonium compared to amino acids for the non- Saccharomyces species. This finding underlines the importance of nitrogen sources, which modulate the functional characteristics of inoculated yeast strains to better control the fermentation process and product quality. Copyright © 2018 Englezos et al.

Mapping Genetic Variants Underlying Differences in the Central Nitrogen Metabolism in Fermenter Yeasts

PubMed Central

García, Verónica; Salinas, Francisco; Aguilera, Omayra; Liti, Gianni; Martínez, Claudio

2014-01-01

Different populations within a species represent a rich reservoir of allelic variants, corresponding to an evolutionary signature of withstood environmental constraints. Saccharomyces cerevisiae strains are widely utilised in the fermentation of different kinds of alcoholic beverages, such as, wine and sake, each of them derived from must with distinct nutrient composition. Importantly, adequate nitrogen levels in the medium are essential for the fermentation process, however, a comprehensive understanding of the genetic variants determining variation in nitrogen consumption is lacking. Here, we assessed the genetic factors underlying variation in nitrogen consumption in a segregating population derived from a cross between two main fermenter yeasts, a Wine/European and a Sake isolate. By linkage analysis we identified 18 main effect QTLs for ammonium and amino acids sources. Interestingly, majority of QTLs were involved in more than a single trait, grouped based on amino acid structure and indicating high levels of pleiotropy across nitrogen sources, in agreement with the observed patterns of phenotypic co-variation. Accordingly, we performed reciprocal hemizygosity analysis validating an effect for three genes, GLT1, ASI1 and AGP1. Furthermore, we detected a widespread pleiotropic effect on these genes, with AGP1 affecting seven amino acids and nine in the case of GLT1 and ASI1. Based on sequence and comparative analysis, candidate causative mutations within these genes were also predicted. Altogether, the identification of these variants demonstrate how Sake and Wine/European genetic backgrounds differentially consume nitrogen sources, in part explaining independently evolved preferences for nitrogen assimilation and representing a niche of genetic diversity for the implementation of practical approaches towards more efficient strains for nitrogen metabolism. PMID:24466135

Burkholderia vietnamiensis isolated from root tissues of Nipa Palm (Nypa fruticans) in Sarawak, Malaysia, proved to be its major endophytic nitrogen-fixing bacterium.

PubMed

Tang, Sui-Yan; Hara, Shintaro; Melling, Lulie; Goh, Kah-Joo; Hashidoko, Yasuyuki

2010-01-01

Root-associating bacteria of the nipa palm (Nypa fruticans), preferring brackish-water affected mud in Sarawak, Malaysia, were investigated. In a comparison of rhizobacterial microbiota between the nipa and the sago (Metroxylon sagu) palm, it was found that the nipa palm possessed a group of Burkholderia vietnamiensis as its main active nitrogen-fixing endophytic bacterium. Acetylene reduction by the various isolates of B. vietnamiensis was constant (44 to 68 nmol h(-1) in ethylene production rate) in soft gel medium containing 0.2% sucrose as sole carbon source, and the bacterium also showed motility and biofilm-forming capacity. This is the first report of endophytic nitrogen-fixing bacteria from nipa palm.

Bonding properties and bond activation of ylides: recent findings and outlook.

PubMed

Urriolabeitia, Esteban P

2008-11-14

The interaction of phosphorus and nitrogen ylides with metallic precursors has been examined from different points of view. The first one is related to the bonding properties of the ylides. Ylides with a unique stabilizing group bond through different atoms (the Calpha or the heteroatoms); while ylides with two stabilizing groups never coordinate through the Calpha atom. In the second section we examine the cause of the stereoselective coordination of bisylides of phosphorus, nitrogen and arsenic, and of mixed bisylides. We describe here the very interesting conformational preferences found in these systems, which have been determined and characterized. The DFT study of these bisylides has allowed for the characterization of strong intramolecular PO and AsO interactions, as well as moderate CHO[double bond, length as m-dash]C hydrogen bonds as the source of these conformational preferences. The third topic is related to the amazing reactivity of phosphorus ylides in bond activation processes. Depending on the nature of the metallic precursors, ylides can behave as sources of carbenes, of phosphine derivatives, of other ylides or of orthometallated complexes through P[double bond, length as m-dash]C, P-C or C-H bond activation reactions.

A Nitrogen Response Pathway Regulates Virulence Functions in Fusarium oxysporum via the Protein Kinase TOR and the bZIP Protein MeaB[C][W

PubMed Central

López-Berges, Manuel S.; Rispail, Nicolas; Prados-Rosales, Rafael C.; Di Pietro, Antonio

2010-01-01

During infection, fungal pathogens activate virulence mechanisms, such as host adhesion, penetration and invasive growth. In the vascular wilt fungus Fusarium oxysporum, the mitogen-activated protein kinase Fmk1 is required for plant infection and controls processes such as cellophane penetration, vegetative hyphal fusion, or root adhesion. Here, we show that these virulence-related functions are repressed by the preferred nitrogen source ammonium and restored by treatment with l-methionine sulfoximine or rapamycin, two specific inhibitors of Gln synthetase and the protein kinase TOR, respectively. Deletion of the bZIP protein MeaB also resulted in nitrogen source–independent activation of virulence mechanisms. Activation of these functions did not require the global nitrogen regulator AreA, suggesting that MeaB-mediated repression of virulence functions does not act through inhibition of AreA. Tomato plants (Solanum lycopersicum) supplied with ammonium rather than nitrate showed a significant reduction in vascular wilt symptoms when infected with the wild type but not with the ΔmeaB strain. Nitrogen source also affected invasive growth in the rice blast fungus Magnaporthe oryzae and the wheat head blight pathogen Fusarium graminearum. We propose that a conserved nitrogen-responsive pathway might operate via TOR and MeaB to control virulence in plant pathogenic fungi. PMID:20639450

Intracellular Growth Is Dependent on Tyrosine Catabolism in the Dimorphic Fungal Pathogen Penicillium marneffei

PubMed Central

Boyce, Kylie J.; McLauchlan, Alisha; Schreider, Lena; Andrianopoulos, Alex

2015-01-01

During infection, pathogens must utilise the available nutrient sources in order to grow while simultaneously evading or tolerating the host’s defence systems. Amino acids are an important nutritional source for pathogenic fungi and can be assimilated from host proteins to provide both carbon and nitrogen. The hpdA gene of the dimorphic fungus Penicillium marneffei, which encodes an enzyme which catalyses the second step of tyrosine catabolism, was identified as up-regulated in pathogenic yeast cells. As well as enabling the fungus to acquire carbon and nitrogen, tyrosine is also a precursor in the formation of two types of protective melanin; DOPA melanin and pyomelanin. Chemical inhibition of HpdA in P. marneffei inhibits ex vivo yeast cell production suggesting that tyrosine is a key nutrient source during infectious growth. The genes required for tyrosine catabolism, including hpdA, are located in a gene cluster and the expression of these genes is induced in the presence of tyrosine. A gene (hmgR) encoding a Zn(II)2-Cys6 binuclear cluster transcription factor is present within the cluster and is required for tyrosine induced expression and repression in the presence of a preferred nitrogen source. AreA, the GATA-type transcription factor which regulates the global response to limiting nitrogen conditions negatively regulates expression of cluster genes in the absence of tyrosine and is required for nitrogen metabolite repression. Deletion of the tyrosine catabolic genes in the cluster affects growth on tyrosine as either a nitrogen or carbon source and affects pyomelanin, but not DOPA melanin, production. In contrast to other genes of the tyrosine catabolic cluster, deletion of hpdA results in no growth within macrophages. This suggests that the ability to catabolise tyrosine is not required for macrophage infection and that HpdA has an additional novel role to that of tyrosine catabolism and pyomelanin production during growth in host cells. PMID:25812137

Ammonium and Nitrate Uptake by the Floating Plant Landoltia punctata

PubMed Central

Fang, Yun Ying; Babourina, Olga; Rengel, Zed; Yang, Xiao E.; Pu, Pei Min

2007-01-01

Background and Aims Plants from the family Lemnaceae are widely used in ecological engineering projects to purify wastewater and eutrophic water bodies. However, the biology of nutrient uptake mechanisms in plants of this family is still poorly understood. There is controversy over whether Lemnaceae roots are involved in nutrient uptake. No information is available on nitrogen (N) preferences and capacity of Landoltia punctata (dotted duckweed), one of the best prospective species in Lemnaceae for phytomelioration and biomass production. The aim of this study was to assess L. punctata plants for their ability to take up NH4+ and NO3− by both roots and fronds. Methods NO3− and NH4+ fluxes were estimated by a non-invasive ion-selective microelectrode technique. This technique allows direct measurements of ion fluxes across the root or frond surface of an intact plant. Key Results Landoltia punctata plants took up NH4+ and NO3− by both fronds and roots. Spatial distribution of NH4+ and NO3− fluxes demonstrated that, although ion fluxes at the most distal parts of the root were uneven, the mature part of the root was involved in N uptake. Despite the absolute flux values for NH4+ and NO3− being lower in roots than at the frond surface, the overall capacity of roots to take up ions was similar to that of fronds because the surface area of roots was larger. L. punctata plants preferred to take up NH4+ over NO3− when both N sources were available. Conclusions Landoltia punctata plants take up nitrogen by both roots and fronds. When both sources of N are available, plants prefer to take up NH4+, but will take up NO3− when it is the only N source. PMID:17204539

Within-city contrasts in PM composition and sources and their relationship with nitrogen oxides.

PubMed

Minguillón, M C; Rivas, I; Aguilera, I; Alastuey, A; Moreno, T; Amato, F; Sunyer, J; Querol, X

2012-10-26

The present work is part of the INMA (INfancia y Medio Ambiente -'Environment and Childhood') project, which aims at assessing the adverse effects of exposure to air pollution during pregnancy and early in life. The present study was performed in the city of Sabadell (Northeast Spain) at three sampling sites covering different traffic characteristics, during two times of the year. It assesses time and spatial variations of PM(2.5) concentrations, chemical components and source contributions, as well as gaseous pollutants. Furthermore, a cross-correlation analysis of PM components and source contributions with gaseous pollutants used as a proxy for exposure assessment is carried out. Our data show the influence of traffic emissions in the Sabadell area. The main PM sources identified by Positive Matrix Factorisation (PMF) were similar between the two seasons: mineral source (traffic-induced resuspension, demolition/construction and natural background), secondary sulphate (higher in summer), secondary nitrate (only during winter), industrial, and road traffic, which was the main contributor to PM(2.5) at two of the sites. The correlation of concentrations of nitrogen oxides was especially strong with those of elemental carbon (EC). The relatively weaker correlations with organic carbon (OC) in summer are attributed to the variable formation of secondary OC. Strong correlations between concentration of nitrogen oxides and PM(2.5) road traffic contributions obtained from source apportionment analysis were seen at all sites. Therefore, under the studied urban environment, nitrogen oxides can be used as a proxy for the exposure to road traffic contribution to PM(2.5); the use of NO(x) concentrations being preferred, with NO and NO(2) as second and third options, respectively.

Optimization of Carbon and Nitrogen Sources for Extracellular Polymeric Substances Production by Chryseobacterium indologenes MUT.2.

PubMed

Khani, Mojtaba; Bahrami, Ali; Chegeni, Asma; Ghafari, Mohammad Davoud; Mansouran Zadeh, ALi

2016-06-01

Bacterial Extracellular Polymeric Substances (EPS) are environmental friendly and versatile polymeric materials that are used in a wide range of industries such as: food, textile, cosmetics, and pharmaceuticals. To make the production process of the EPS cost-effective, improvements in the production yield is required which could be implemented through application of processes such as optimized culture conditions, and development of the strains with higher yield ( e.g . through genetic manipulation), or using low-cost substrates. In this work, the effects of carbon and nitrogen sources were studied in order to improve the EPS production by the submerged cultivation of Chryseobacterium indologenes MUT.2. The mesophilic microorganism Chryseobacterium indologenes MUT.2, was grown and maintained in the Luria Bertani agar. The initial basal medium contained: glucose (20 g.L -1 ), yeast extracts (5 g.L -1 ), K 2 HPO 4 (6 g.L -1 ), NaH 2 PO 4 (7 g.L -1 ), NH 4 CL (0.7 g.L -1 ), and MgSO 4 (0.5 g.L -1 ). For evaluating the carbon and nitrogen sources' effect on the fermentation performance, cultures were prepared in 500 mL flasks filled with 300 mL of the medium. The single-factor experiments based on statistics was employed to evaluate and optimize the carbon and nitrogen sources for EPS production in the liquid culture medium of Chryseobacterium indologenes MUT.2. The preferred carbon-sources, sucrose and glucose, commonly gave the highest EPS production of 8.32 and 6.37 g.L -1 , respectively, and the maximum EPS production of 8.87 g.L -1 was achieved when glutamic acid (5 g.L -1 ) was employed as the nitrogen source. In this work, the culture medium for production of EPS by Chryseobacterium indologenes MUT.2 was optimized. Compared to the basal culture medium in shake-flasks and stirred tank bioreactor, the use of optimized culture medium has resulted in a 53% and 73% increase in the EPS production, respectively.

An alternative pathway for marine nitrous oxide production at oxic-anoxic interfaces from coupled biotic-abiotic reactions

NASA Astrophysics Data System (ADS)

Glass, J. B.; Stanton, C. L.; Ochoa, H.; Haslun, J. A.; Gandhi, H.; Taillefert, M.; Dichristina, T. J.; Stewart, F. J.; Klotz, M. G.; Ostrom, N. E.

2016-02-01

Marine emissions of nitrous oxide (N2O), a potent greenhouse gas, comprise approximately a third of global sources. Recent evidence suggests that the dominant source of N2O in seawater is the activity of ammonia-oxidizing Thaumarchaeota that lack characterized N2O-generating enzymes. Nitrous oxide may arise from a novel enzyme and/or abiotic reactions between nitrification intermediates, hydroxylamine (NH2OH) and nitric oxide (NO), and redox-active metals in seawater. Isotopic site preference, or difference in δ15N between the two nitrogen atoms in N2O, has been used as tracer for microbial N2O production pathways (-10 to 0‰ for nitrifier-denitrification and denitrification vs. 30-37‰ for nitrification via NH2OH oxidation). Seawater N2O site preference falls in between these two characterized end members, suggesting simultaneous production via a combination of both microbial pathways or via a novel mechanism with intermediate site preference. Here we show significant N2O production in abiotic experiments after addition of iron to seawater containing NH2OH and NO. The N2O produced from chemical reduction of NO by Fe(II) had a site preference of 16‰ whereas N2O produced from abiotic NH2OH oxidation had a site preference of 31‰. We propose that coupled biotic-abiotic N2O production pathways could contribute significant sources of N2O at marine oxic-anoxic interfaces.

Seabird guano fertilizes Baltic Sea littoral food webs.

PubMed

Gagnon, Karine; Rothäusler, Eva; Syrjänen, Anneli; Yli-Renko, Maria; Jormalainen, Veijo

2013-01-01

Nutrient enrichment in coastal marine systems can have profound impacts on trophic networks. In the Baltic Sea, the population of Great Cormorant (Phalacrocorax carbo sinensis) has increased nearly exponentially since the mid-1990 s, and colonies of these seabirds can be important sources of nitrogen enrichment for nearby benthic communities due to guano runoff. In this study we used stable isotope analyses and diet mixing models to determine the extent of nitrogen enrichment from cormorant colonies, as well as to examine any possible changes in herbivore diet preferences due to enrichment. We found significantly higher levels of δ(15)N in samples from colony islands than control islands for producers (the dominant macroalga Fucus vesiculosus, filamentous algae, and periphyton) and herbivores, as well as a positive correlation between enrichment and nest density in colony sites. We also found that enrichment increased over the breeding season of the cormorants, with higher enrichment in late summer than early summer. While the amount of total nitrogen did not differ between colony and control sites, the amount of guano-based nitrogen in algae was >50% in most sites, indicating high nitrogen enrichment from colonies. Herbivores (the isopod Idotea balthica and the gastropod Theodoxus fluviatilis) preferred feeding upon the dominant macroalga Fucus vesiculosus rather than on filamentous algae or periphyton in both control and colony, and there was a significant increase in periphyton consumption near colony sites. Overall, guano from cormorant colonies seems to have effects on both producers and herbivores, as well as the potential to modify algae-herbivore interactions.

Seabird Guano Fertilizes Baltic Sea Littoral Food Webs

PubMed Central

Gagnon, Karine; Rothäusler, Eva; Syrjänen, Anneli; Yli-Renko, Maria; Jormalainen, Veijo

2013-01-01

Nutrient enrichment in coastal marine systems can have profound impacts on trophic networks. In the Baltic Sea, the population of Great Cormorant (Phalacrocorax carbo sinensis) has increased nearly exponentially since the mid-1990s, and colonies of these seabirds can be important sources of nitrogen enrichment for nearby benthic communities due to guano runoff. In this study we used stable isotope analyses and diet mixing models to determine the extent of nitrogen enrichment from cormorant colonies, as well as to examine any possible changes in herbivore diet preferences due to enrichment. We found significantly higher levels of δ15N in samples from colony islands than control islands for producers (the dominant macroalga Fucus vesiculosus, filamentous algae, and periphyton) and herbivores, as well as a positive correlation between enrichment and nest density in colony sites. We also found that enrichment increased over the breeding season of the cormorants, with higher enrichment in late summer than early summer. While the amount of total nitrogen did not differ between colony and control sites, the amount of guano-based nitrogen in algae was >50% in most sites, indicating high nitrogen enrichment from colonies. Herbivores (the isopod Idotea balthica and the gastropod Theodoxus fluviatilis) preferred feeding upon the dominant macroalga Fucus vesiculosus rather than on filamentous algae or periphyton in both control and colony, and there was a significant increase in periphyton consumption near colony sites. Overall, guano from cormorant colonies seems to have effects on both producers and herbivores, as well as the potential to modify algae-herbivore interactions. PMID:23593452

Identification of a Novel Regulatory Mechanism of Nutrient Transport Controlled by TORC1-Npr1-Amu1/Par32

PubMed Central

Boeckstaens, Mélanie; Merhi, Ahmad; Llinares, Elisa; Van Vooren, Pascale; Springael, Jean-Yves; Wintjens, René; Marini, Anna Maria

2015-01-01

Fine-tuning the plasma-membrane permeability to essential nutrients is fundamental to cell growth optimization. Nutritional signals including nitrogen availability are integrated by the TORC1 complex which notably regulates arrestin-mediated endocytosis of amino-acid transporters. Ammonium is a ubiquitous compound playing key physiological roles in many, if not all, organisms. In yeast, it is a preferred nitrogen source transported by three Mep proteins which are orthologues of the mammalian Rhesus factors. By combining genetic, kinetic, biochemical and cell microscopy analyses, the current study reveals a novel mechanism enabling TORC1 to regulate the inherent activity of ammonium transport proteins, independently of arrestin-mediated endocytosis, identifying the still functional orphan Amu1/Par32 as a selective regulator intermediate. We show that, under poor nitrogen supply, the TORC1 effector kinase' Npr1' promotes phosphorylation of Amu1/Par32 which appears mainly cytosolic while ammonium transport proteins are active. Upon preferred nitrogen supplementation, like glutamine or ammonium addition, TORC1 upregulation enables Npr1 inhibition and Amu1/Par32 dephosphorylation. In these conditions, as in Npr1-lacking cells, hypophosphorylated Amu1/Par32 accumulates at the cell surface and mediates the inhibition of specific ammonium transport proteins. We show that the integrity of a conserved repeated motif of Amu1/Par32 is required for the interaction with these transport proteins. This study underscores the diversity of strategies enabling TORC1-Npr1 to selectively monitor cell permeability to nutrients by discriminating between transporters to be degraded or transiently inactivated and kept stable at the plasma membrane. This study further identifies the function of Amu1/Par32 in acute control of ammonium transport in response to variations in nitrogen availability. PMID:26172854

Field emission from bias-grown diamond thin films in a microwave plasma

DOEpatents

Gruen, Dieter M.; Krauss, Alan R.; Ding, Ming Q.; Auciello, Orlando

2002-01-01

A method of producing diamond or diamond like films in which a negative bias is established on a substrate with an electrically conductive surface in a microwave plasma chemical vapor deposition system. The atmosphere that is subjected to microwave energy includes a source of carbon, nitrogen and hydrogen. The negative bias is maintained on the substrate through both the nucleation and growth phase of the film until the film is continuous. Biases between -100V and -200 are preferred. Carbon sources may be one or more of CH.sub.4, C.sub.2 H.sub.2 other hydrocarbons and fullerenes.

Nitrogen-source preference in blueberry (Vaccinium sp.): Enhanced shoot nitrogen assimilation in response to direct supply of nitrate.

PubMed

Alt, Douglas S; Doyle, John W; Malladi, Anish

2017-09-01

Blueberry (Vaccinium sp.) is thought to display a preference for the ammonium (NH 4 + ) form over the nitrate (NO 3 - ) form of inorganic nitrogen (N). This N-source preference has been associated with a generally low capacity to assimilate the NO 3 - form of N, especially within the shoot tissues. Nitrate assimilation is mediated by nitrate reductase (NR), a rate limiting enzyme that converts NO 3 - to nitrite (NO 2 - ). We investigated potential limitations of NO 3 - assimilation in two blueberry species, rabbiteye (Vaccinium ashei) and southern highbush (Vaccinium corymbosum) by supplying NO 3 - to the roots, leaf surface, or through the cut stem. Both species displayed relatively low but similar root uptake rates for both forms of inorganic N. Nitrate uptake through the roots transiently increased NR activity by up to 3.3-fold and root NR gene expression by up to 4-fold. However, supplying NO 3 - to the roots did not increase its transport in the xylem, nor did it increase NR activity in the leaves, indicating that the acquired N was largely assimilated or stored within the roots. Foliar application of NO 3 - increased leaf NR activity by up to 3.5-fold, but did not alter NO 3 - metabolism-related gene expression, suggesting that blueberries are capable of post translational regulation of NR activity in the shoots. Additionally, supplying NO 3 - to the cut ends of stems resulted in around a 5-fold increase in NR activity, a 10-fold increase in NR transcript accumulation, and up to a 195-fold increase in transcript accumulation of NITRITE REDUCTASE (NiR1) which codes for the enzyme catalyzing the conversion of NO 2 - to NH 4 + . These data indicate that blueberry shoots are capable of assimilating NO 3 - when it is directly supplied to these tissues. Together, these data suggest that limitations in the uptake and translocation of NO 3 - to the shoots may limit overall NO 3 - assimilation capacity in blueberry. Copyright © 2017 Elsevier GmbH. All rights reserved.

Isolation, identification, and culture optimization of a novel glycinonitrile-hydrolyzing fungus-Fusarium oxysporum H3.

PubMed

Gong, Jin-Song; Lu, Zhen-Ming; Shi, Jing-Song; Dou, Wen-Fang; Xu, Hong-Yu; Zhou, Zhe-Min; Xu, Zheng-Hong

2011-10-01

Microbial transformation of glycinonitrile into glycine by nitrile hydrolase is of considerable interest to green chemistry. A novel fungus with high nitrile hydrolase was newly isolated from soil samples and identified as Fusarium oxysporum H3 through 18S ribosomal DNA, 28S ribosomal DNA, and the internal transcribed spacer sequence analysis, together with morphology characteristics. After primary optimization of culture conditions including pH, temperature, carbon/nitrogen sources, inducers, and metal ions, the enzyme activity was greatly increased from 326 to 4,313 U/L. The preferred carbon/nitrogen sources, inducer, and metal ions were glucose and yeast extract, caprolactam, and Cu(2+), Mn(2+), and Fe(2+), respectively. The maximum enzyme formation was obtained when F. oxysporum H3 was cultivated at 30 °C for 54 h with the initial pH of 7.2. There is scanty report about the optimization of nitrile hydrolase production from nitrile-converting fungus.

Effect of different forage species on the nitrogen uptake in Hulunbeir

NASA Astrophysics Data System (ADS)

Xu, Li-Jun; Xu, Xing-Liang; Tang, Xue-Juan; Yang, Gui-Xia; Zhang, Zhao; Xin, Xiao-Ping

2017-02-01

Knowledge of determining factors for nitrogen uptake preferences and how they are modified in changing environments are critical to understand ecosystem nitrogen cycling and to predict plant responses to future environmental changes. However, it remains unclear in this aspect for the main managed grassland (Medicago sativa, Bromus inermis, Leymus chinensis) and crop (Brassica campestris) under field condition in Hulunbeir area of Inner Mongolia of China. Two 15N tracer experiments utilizing a unique differential labelled nitrogen source were employed in both managed grassland (M. sativa, B. inermis and L. chinensis) and crop (B. campestris) in Hulunbeir area of Inner Mongolia of China. Tracing both labels in the above-and below ground plant biomass, soil NH4 + -N or NO3 - -N and NH4 + -N or NO3 - -N uptake by plants. There were differences between soil NO3 --N concentration and NH4+-N concentration, and NO3 --N concentration was higher than NH4 +-N concentration. NO3 --N concentration was led by different grass species. The NH4 +-N concentration in August were higher than in July on the whole, the highest value for B. campestris and the lowest for B. inermis. The plant N concentration in B. inermis, L. chinensis and B. campestris showed decreasing trend, its mean value decreased by 20.1, 47.9 and 26.7%, respectively, and M. sativa increased by 13.7%. Among the four species, the individuals exhibited a preference for 15NO3 -, indicated by higher 15N signatures in 15NO3-treatment than in 15NH4 + treatment.

Optimization of Carbon and Nitrogen Sources for Extracellular Polymeric Substances Production by Chryseobacterium indologenes MUT.2

PubMed Central

Khani, Mojtaba; Bahrami, Ali; Chegeni, Asma; Ghafari, Mohammad Davoud; Mansouran Zadeh, ALi

2016-01-01

Background Bacterial Extracellular Polymeric Substances (EPS) are environmental friendly and versatile polymeric materials that are used in a wide range of industries such as: food, textile, cosmetics, and pharmaceuticals. To make the production process of the EPS cost-effective, improvements in the production yield is required which could be implemented through application of processes such as optimized culture conditions, and development of the strains with higher yield (e.g. through genetic manipulation), or using low-cost substrates. Objectives In this work, the effects of carbon and nitrogen sources were studied in order to improve the EPS production by the submerged cultivation of Chryseobacterium indologenes MUT.2. Materials and Methods The mesophilic microorganism Chryseobacterium indologenes MUT.2, was grown and maintained in the Luria Bertani agar. The initial basal medium contained: glucose (20 g.L-1), yeast extracts (5 g.L-1), K2HPO4 (6 g.L-1), NaH2PO4 (7 g.L-1), NH4CL (0.7 g.L-1), and MgSO4 (0.5 g.L-1). For evaluating the carbon and nitrogen sources’ effect on the fermentation performance, cultures were prepared in 500 mL flasks filled with 300 mL of the medium. The single-factor experiments based on statistics was employed to evaluate and optimize the carbon and nitrogen sources for EPS production in the liquid culture medium of Chryseobacterium indologenes MUT.2. Results The preferred carbon-sources, sucrose and glucose, commonly gave the highest EPS production of 8.32 and 6.37 g.L-1, respectively, and the maximum EPS production of 8.87 g.L-1 was achieved when glutamic acid (5 g.L-1) was employed as the nitrogen source. Conclusions In this work, the culture medium for production of EPS by Chryseobacterium indologenes MUT.2 was optimized. Compared to the basal culture medium in shake-flasks and stirred tank bioreactor, the use of optimized culture medium has resulted in a 53% and 73% increase in the EPS production, respectively. PMID:28959321

Source of Nitrous Oxide Emissions during the Cow Manure Composting Process as Revealed by Isotopomer Analysis of and amoA Abundance in Betaproteobacterial Ammonia-Oxidizing Bacteria▿ †

PubMed Central

Maeda, Koki; Toyoda, Sakae; Shimojima, Ryosuke; Osada, Takashi; Hanajima, Dai; Morioka, Riki; Yoshida, Naohiro

2010-01-01

A molecular analysis of betaproteobacterial ammonia oxidizers and a N2O isotopomer analysis were conducted to study the sources of N2O emissions during the cow manure composting process. Much NO2−-N and NO3−-N and the Nitrosomonas europaea-like amoA gene were detected at the surface, especially at the top of the composting pile, suggesting that these ammonia-oxidizing bacteria (AOB) significantly contribute to the nitrification which occurs at the surface layer of compost piles. However, the 15N site preference within the asymmetric N2O molecule (SP = δ15Nα − δ15Nβ, where 15Nα and 15Nβ represent the 15N/14N ratios at the center and end sites of the nitrogen atoms, respectively) indicated that the source of N2O emissions just after the compost was turned originated mainly from the denitrification process. Based on these results, the reduction of accumulated NO2−-N or NO3−-N after turning was identified as the main source of N2O emissions. The site preference and bulk δ15N results also indicate that the rate of N2O reduction was relatively low, and an increased value for the site preference indicates that the nitrification which occurred mainly in the surface layer of the pile partially contributed to N2O emissions between the turnings. PMID:20048060

Source of nitrous oxide emissions during the cow manure composting process as revealed by isotopomer analysis of and amoA abundance in betaproteobacterial ammonia-oxidizing bacteria.

PubMed

Maeda, Koki; Toyoda, Sakae; Shimojima, Ryosuke; Osada, Takashi; Hanajima, Dai; Morioka, Riki; Yoshida, Naohiro

2010-03-01

A molecular analysis of betaproteobacterial ammonia oxidizers and a N(2)O isotopomer analysis were conducted to study the sources of N(2)O emissions during the cow manure composting process. Much NO(2)(-)-N and NO(3)(-)-N and the Nitrosomonas europaea-like amoA gene were detected at the surface, especially at the top of the composting pile, suggesting that these ammonia-oxidizing bacteria (AOB) significantly contribute to the nitrification which occurs at the surface layer of compost piles. However, the (15)N site preference within the asymmetric N(2)O molecule (SP = delta(15)N(alpha) - delta(15)N(beta), where (15)N(alpha) and (15)N(beta) represent the (15)N/(14)N ratios at the center and end sites of the nitrogen atoms, respectively) indicated that the source of N(2)O emissions just after the compost was turned originated mainly from the denitrification process. Based on these results, the reduction of accumulated NO(2)(-)-N or NO(3)(-)-N after turning was identified as the main source of N(2)O emissions. The site preference and bulk delta(15)N results also indicate that the rate of N(2)O reduction was relatively low, and an increased value for the site preference indicates that the nitrification which occurred mainly in the surface layer of the pile partially contributed to N(2)O emissions between the turnings.

Nitrate-Regulated Glutaredoxins Control Arabidopsis Primary Root Growth1[OPEN

PubMed Central

Walters, Laura A.; Cooper, Andrew M.; Olvera, Jocelyn G.; Rosas, Miguel A.; Rasmusson, Allan G.

2016-01-01

Nitrogen is an essential soil nutrient for plants, and lack of nitrogen commonly limits plant growth. Soil nitrogen is typically available to plants in two inorganic forms: nitrate and ammonium. To better understand how nitrate and ammonium differentially affect plant metabolism and development, we performed transcriptional profiling of the shoots of ammonium-supplied and nitrate-supplied Arabidopsis (Arabidopsis thaliana) plants. Seven genes encoding class III glutaredoxins were found to be strongly and specifically induced by nitrate. RNA silencing of four of these glutaredoxin genes (AtGRXS3/4/5/8) resulted in plants with increased primary root length (approximately 25% longer than the wild type) and decreased sensitivity to nitrate-mediated inhibition of primary root growth. Increased primary root growth is also a well-characterized phenotype of many cytokinin-deficient plant lines. We determined that nitrate induction of glutaredoxin gene expression was dependent upon cytokinin signaling and that cytokinins could activate glutaredoxin gene expression independent of plant nitrate status. In addition, crosses between “long-root” cytokinin-deficient plants and “long-root” glutaredoxin-silenced plants generated hybrids that displayed no further increase in primary root length (i.e. epistasis). Collectively, these findings suggest that AtGRXS3/4/5/8 operate downstream of cytokinins in a signal transduction pathway that negatively regulates plant primary root growth in response to nitrate. This pathway could allow Arabidopsis to actively discriminate between different nitrogen sources in the soil, with the preferred nitrogen source, nitrate, acting to suppress primary root growth (vertical dimension) in concert with its well-characterized stimulatory effect on lateral root growth (horizontal dimension). PMID:26662603

NITROGEN UPTAKE AND ASSIMILATION IN ENTEROMORPHA INTESTINALIS (L.) LINK (CHLOROPHYTA): USING 15N TO DETERMINE PREFERENCE DURING SIMULTANEOUS PULSES OF NITRATE AND AMMONIUM. (R827637)

EPA Science Inventory

We investigated the ability of Enteromorpha intestinalis (L.) Link to take up pulses of different species of nitrogen simultaneously, as this would be an important mechanism to enhance bloom ability in estuaries. Uptake rates and preference for NH₄⁺

Electrochemical process for the preparation of nitrogen fertilizers

DOEpatents

Aulich, Ted R.; Olson, Edwin S.; Jiang, Junhua

2013-03-19

The present invention provides methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia utilizing a source of carbon, a source of nitrogen, and/or a source of hydrogen. Implementing an electrolyte serving as ionic charge carrier, (1) ammonium nitrate is produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers are produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source; (3) ammonia is produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source at the anode; and (4) urea-ammonium nitrate is produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source. The electrolyte can be solid.

Signatures in Martian Volatiles and the Magma Sources of NC Meteorites

NASA Technical Reports Server (NTRS)

Marti, K.; Mathew, K. J.

2004-01-01

We report nitrogen and xenon isotopic signatures in Yamato nakhlites and use the data to assess properties of the magma source of NC meteorites in planet Mars. The Chassigny meteorite was investigated by Floran et al, who classified it as a cumulate dunite with hydrous amphibole-bearing melt inclusions with no preferred orientation of the olivines. Their inferred composition of the parent magma, which was based on electron microprobe analyses, has been questioned. The trace and minor elements in minerals were analyzed in nakhlites and in Chassigny and the authors conclude that nakhlites may represent samples from different horizons of the same lithologic unit, but that Chassigny was not co-magmatic with the nakhlites.

Genome-wide identification, classification and transcriptional analysis of nitrate and ammonium transporters in Coffea

PubMed Central

dos Santos, Tiago Benedito; Lima, Joni Esrom; Felicio, Mariane Silva; Soares, João Danillo Moura; Domingues, Douglas Silva

2017-01-01

Abstract Nitrogen (N) is quantitatively the main nutrient required by coffee plants, with acquisition mainly by the roots and mostly exported to coffee beans. Nitrate (NO3 –) and ammonium (NH4 +) are the most important inorganic sources for N uptake. Several N transporters encoded by different gene families mediate the uptake of these compounds. They have an important role in source preference for N uptake in the root system. In this study, we performed a genome-wide analysis, including in silico expression and phylogenetic analyses of AMT1, AMT2, NRT1/PTR, and NRT2 transporters in the recently sequenced Coffea canephora genome. We analyzed the expression of six selected transporters in Coffea arabica roots submitted to N deficiency. N source preference was also analyzed in C. arabica using isotopes. C. canephora N transporters follow the patterns observed for most eudicots, where each member of the AMT and NRT families has a particular role in N mobilization, and where some of these are modulated by N deficiency. Despite the prevalence of putative nitrate transporters in the Coffea genome, ammonium was the preferential inorganic N source for N-starved C. arabica roots. This data provides an important basis for fundamental and applied studies to depict molecular mechanisms involved in N uptake in coffee trees. PMID:28399192

Synthesis of refractory materials

DOEpatents

Holt, J.B.

1983-08-16

Refractory metal nitrides are synthesized during a self-propagating combustion process utilizing a solid source of nitrogen. For this purpose, a metal azide is employed, preferably NaN/sub 3/. The azide is combusted with Mg or Ca, and a metal oxide is selected from Groups III-A, IV-A, III-B, IV-B, or a rare earth metal oxide. The mixture of azide, Ca or Mg and metal oxide is heated to the mixture's ignition temperature. At that temperature the mixture is ignited and undergoes self-sustaining combustion until the starter materials are exhausted, producing the metal nitride.

Nitrogen uptake by Eucalyptus regnans and Acacia spp. - preferences, resource overlap and energetic costs.

PubMed

Pfautsch, Sebastian; Rennenberg, Heinz; Bell, Tina L; Adams, Mark A

2009-03-01

In southeastern Australia, the overstory species Eucalyptus regnans F. Muell. commonly grows with either of the two leguminous understory trees, Acacia melanoxylon (R. Br. Ex Ait. f.) or Acacia dealbata (Link.). Our objective was to elucidate interactions between the dominant eucalypt and its companion acacias for nitrogen (N) sources. Use of stable N isotopes as tracers revealed that ammonium was the preferred soil N source for all species, nevertheless, total N uptake varied greatly among species. Studies with double-labeled ((13)C/(15)N) glutamine indicated the uptake of this form of organic N in small amounts by both E. regnans and the Acacia spp. These and other data imply that, in contrast to boreal forests, organic N is not a significant component of N nutrition in mountain ash forests. Field and laboratory studies provided evidence that N(2)-fixation capacity of acacias varies with stand development, with N-fixing species playing an important role in N nutrition during the early but not the mature stages of forest growth. An index of N-uptake efficiency - the amount of oxygen consumed per unit N taken up - was compared across four N sources and three species. Nitrate uptake was the least efficient form of N acquisition, especially compared with ammonium uptake which was up to 30-fold less costly. Efficiency of glutamine uptake was intermediate between that of ammonium and nitrate. Differences in uptake efficiency among N forms were most pronounced for the Acacia spp. and least for E. regnans. We conclude that an overlap in requirements among sympatric Acacia spp. and E. regnans for specific soil N sources can be bypassed because of changes in biochemical strategies of Acacia spp. triggered by increasing soil N concentrations during stand development. Further studies might elucidate whether this is a common feature of complex forest ecosystems, or a specialty of the interaction between eucalypts and acacias.

Electrochemical process for the preparation of nitrogen fertilizers

DOEpatents

Jiang, Junhua; Aulich, Ted R; Ignatchenko, Alexey V

2015-04-14

Methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia are disclosed. Embodiments include (1) ammonium nitrate produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source: (3) ammonia produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source or a hydrogen equivalent such as carbon monoxide or a mixture of carbon monoxide and hydrogen at the anode; and (4) urea-ammonium nitrate produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source.

Seawater cultivation of freshwater cyanobacterium Synechocystis sp. PCC 6803 drastically alters amino acid composition and glycogen metabolism

PubMed Central

Iijima, Hiroko; Nakaya, Yuka; Kuwahara, Ayuko; Hirai, Masami Yokota; Osanai, Takashi

2015-01-01

Water use assessment is important for bioproduction using cyanobacteria. For eco-friendly reasons, seawater should preferably be used for cyanobacteria cultivation instead of freshwater. In this study, we demonstrated that the freshwater unicellular cyanobacterium Synechocystis sp. PCC 6803 could be grown in a medium based on seawater. The Synechocystis wild-type strain grew well in an artificial seawater (ASW) medium supplemented with nitrogen and phosphorus sources. The addition of HEPES buffer improved cell growth overall, although the growth in ASW medium was inferior to that in the synthetic BG-11 medium. The levels of proteins involved in sugar metabolism changed depending on the culture conditions. The biosynthesis of several amino acids including aspartate, glutamine, glycine, proline, ornithine, and lysine, was highly up-regulated by cultivation in ASW. Two types of natural seawater (NSW) were also made available for the cultivation of Synechocystis cells, with supplementation of both nitrogen and phosphorus sources. These results revealed the potential use of seawater for the cultivation of freshwater cyanobacteria, which would help to reduce freshwater consumption during biorefinery using cyanobacteria. PMID:25954257

[Nitrogen non-point source pollution identification based on ArcSWAT in Changle River].

PubMed

Deng, Ou-Ping; Sun, Si-Yang; Lü, Jun

2013-04-01

The ArcSWAT (Soil and Water Assessment Tool) model was adopted for Non-point source (NPS) nitrogen pollution modeling and nitrogen source apportionment for the Changle River watershed, a typical agricultural watershed in Southeast China. Water quality and hydrological parameters were monitored, and the watershed natural conditions (including soil, climate, land use, etc) and pollution sources information were also investigated and collected for SWAT database. The ArcSWAT model was established in the Changle River after the calibrating and validating procedures of the model parameters. Based on the validated SWAT model, the contributions of different nitrogen sources to river TN loading were quantified, and spatial-temporal distributions of NPS nitrogen export to rivers were addressed. The results showed that in the Changle River watershed, Nitrogen fertilizer, nitrogen air deposition and nitrogen soil pool were the prominent pollution sources, which contributed 35%, 32% and 25% to the river TN loading, respectively. There were spatial-temporal variations in the critical sources for NPS TN export to the river. Natural sources, such as soil nitrogen pool and atmospheric nitrogen deposition, should be targeted as the critical sources for river TN pollution during the rainy seasons. Chemical nitrogen fertilizer application should be targeted as the critical sources for river TN pollution during the crop growing season. Chemical nitrogen fertilizer application, soil nitrogen pool and atmospheric nitrogen deposition were the main sources for TN exported from the garden plot, forest and residential land, respectively. However, they were the main sources for TN exported both from the upland and paddy field. These results revealed that NPS pollution controlling rules should focus on the spatio-temporal distribution of NPS pollution sources.

Fish track wastewater pollution to estuaries.

PubMed

Schlacher, Thomas A; Liddell, Ben; Gaston, Troy F; Schlacher-Hoenlinger, Monika

2005-08-01

Excess nitrogen is a forceful agent of ecological change in coastal waters, and wastewater is a prominent source of nitrogen. In catchments where multiple sources of nitrogen pollution co-exist, biological indicators are needed to gauge the degree to which wastewater-N can propagate through the receiving food webs. The purpose of this study was to test whether estuarine fish are suitable as indicators of sewage-N pollution. Fish were analysed from three estuaries within a 100-km strip on the Australian East Coast. The estuaries differ substantially in wastewater loading: (1) the Maroochy Estuary receives a large fraction of the local shire's treated sewage, (2) the Mooloolah Estuary has no licensed treated wastewater outfalls but marinas/harbours and storm-water may contribute nitrogen, and (3) the Noosa Estuary which neither receives licensed discharges nor has suspected wastewater loads. Sampling for fish included both high rainfall ('wet' season) and low rainfall ('dry' season) periods. Muscle-delta15N was the variable predicted to respond to treated wastewater loading, reflecting the relative enrichment in 15N resulting from the treatment process and distinguishing it from alternative N sources such as fertiliser and natural nitrogen inputs (both 15N-depleted). Of the 19 fish species occurring in all three estuaries, those from the Maroochy Estuary had significantly elevated delta15N values (up to 9.9 per thousand), and inter-estuarine differences in fish-delta15N were consistent across seasons. Furthermore, not only did all fish from the estuary receiving treated wastewater carry a very distinctive sewage-N tissue signal, but enriched muscle-delta15N was also evident in all species sampled from the one estuary in which sewage contamination was previously only suspected (i.e. the Mooloolah Estuary: 0.2-4.8 per thousand enrichment over fish from reference system). Thus, fish-delta15N is a suitable indicator of wastewater-N not only in systems that receive large loads, but also for the detection of more subtle nitrogen inputs. Arguably, fish may be preferred indicators of sewage-N contamination because they: (1) integrate nitrogen inputs over long time periods, (2) have an element of 'ecological relevance' because fish muscle-delta15N reflect movement of sewage-N through the food chain, and (3) pollution assessments can usually be based on evidence from multiple species.

The use of olfactory and visual cues in host choice by the capsid bugs Lygus rugulipennis Poppius and Liocoris tripustulatus fabricius.

PubMed

Wynde, Fiona J H; Port, Gordon R

2012-01-01

Lygus rugulipennis Poppius and Liocoris tripustulatus Fabricius (Heteroptera: Miridae) are pests of glasshouse cucumber and sweet pepper crops respectively. L. rugulipennis has a wide range of foodplants, but L. tripustulatus is specialised with very few food plants. We report behavioural assessments to investigate whether either species exhibits a preference for salad over wild hosts, and whether the role of olfaction and vision in response to cues from host plants can be distinguished. Olfactory responses to leaves were tested in choice chambers. L. rugulipennis was presented nettle (wild host) and a salad leaf of cucumber or sweet pepper, where the salad leaves had higher nitrogen content. L. tripustulatus was tested with nettle and sweet pepper of two different nitrogen contents. Female L. rugulipennis spent more time on the cucumber salad host, and chose it first most often, but males showed no preference. Neither sex discriminated between sweet pepper or nettle leaves, but males made more first contacts with sweet pepper. Neither sex of L. tripustulatus discriminated between sweet pepper and nettle leaves when the sweet pepper had higher nitrogen. When the plant species contained equivalent nitrogen both sexes spent more time on nettle. There was no difference in first choice made by either sex. When visual stimuli were available, and leaves had equivalent nitrogen, L. rugulipennis showed no preference and L. tripustulatus preferred nettle leaves. We conclude that the generalist L. rugulipennis has the ability to use remote olfactory cues for host choice whereas the specialist L. tripustulatus relies mainly on contact chemosensory and gustatory cues.

The Use of Olfactory and Visual Cues in Host Choice by the Capsid Bugs Lygus rugulipennis Poppius and Liocoris tripustulatus Fabricius

PubMed Central

Wynde, Fiona J. H.; Port, Gordon R.

2012-01-01

Lygus rugulipennis Poppius and Liocoris tripustulatus Fabricius (Heteroptera: Miridae) are pests of glasshouse cucumber and sweet pepper crops respectively. L. rugulipennis has a wide range of foodplants, but L. tripustulatus is specialised with very few food plants. We report behavioural assessments to investigate whether either species exhibits a preference for salad over wild hosts, and whether the role of olfaction and vision in response to cues from host plants can be distinguished. Olfactory responses to leaves were tested in choice chambers. L. rugulipennis was presented nettle (wild host) and a salad leaf of cucumber or sweet pepper, where the salad leaves had higher nitrogen content. L. tripustulatus was tested with nettle and sweet pepper of two different nitrogen contents. Female L. rugulipennis spent more time on the cucumber salad host, and chose it first most often, but males showed no preference. Neither sex discriminated between sweet pepper or nettle leaves, but males made more first contacts with sweet pepper. Neither sex of L. tripustulatus discriminated between sweet pepper and nettle leaves when the sweet pepper had higher nitrogen. When the plant species contained equivalent nitrogen both sexes spent more time on nettle. There was no difference in first choice made by either sex. When visual stimuli were available, and leaves had equivalent nitrogen, L. rugulipennis showed no preference and L. tripustulatus preferred nettle leaves. We conclude that the generalist L. rugulipennis has the ability to use remote olfactory cues for host choice whereas the specialist L. tripustulatus relies mainly on contact chemosensory and gustatory cues. PMID:23226493

Evaluation of a catalytic reduction technique for the measurement of total reactive odd-nitrogen NOy in the atmosphere

NASA Technical Reports Server (NTRS)

Fahey, D. W.; Eubank, C. S.; Hubler, C. S.; Fehsenfeld, F. C.

1985-01-01

The suitability of a technique for the measurement of total reactive odd-nitrogen NOy-containing species in the atmosphere has been examined. In the technique, an NOy component species, which may include NO, NO2, NO3, HNO3, peroxyacetyl nitrate, and particulate nitrate, are catalytically reduced by CO to form NO molecules on the surface of a metal converter tube, and the NO product is detected by chemiluminescence produced in reaction with O3. Among the catalysts tested in the temperature range of 25-500 C, Au was the preferred catalyst. The results of laboratory tests investigating the effects of pressure, O3, and H2O on NOy conversion, and the possible sources of interference, have shown that the technique is suitable for atmospheric analyses. The results of a test in ambient air at a remote ground-based field site are included.

Organic Carbon Sources and their Transfer in a Gulf of Mexico Coral Reef Ecosystem under River Influence

NASA Astrophysics Data System (ADS)

Parrish, C.; Carreón-Palau, L.; del Ángel-Rodríguez, J.; Perez-Espana, H.; Aguiniga-Garcıa, S.

2016-02-01

To assess the degree to which coral reefs in a marine protected area have been influenced by terrestrial and anthropogenic organic carbon inputs we used C and N stable isotopes and lipid biomarkers in the Coral Reef System of Veracruz in the southwest Gulf of Mexico. A C and N stable isotope mixing model and a calculated fatty acid (FA) retention factor revealed the primary producer sources that fuel the coral reef food web. Then lipid classes, FA and sterol biomarkers determined production of terrestrial and marine biogenic material of nutritional quality to pelagic and benthic organisms. Finally, coprostanol determined pollutant loading from sewage in the suspended particulate matter. Results indicate that phytoplankton is the major source of essential FA for fish and that dietary energy from terrestrial sources such as mangroves are transferred to juvenile fish, while sea grass non-essential FA are transferred to the entire food web. Sea urchins may be the main consumers of brown macroalgae, while surgeon fish prefer red algae. C and N isotopic values and the C:N ratio suggest that fertilizer is the principal source of nitrogen to macroalgae. Thus nitrogen supply also favored phytoplankton and sea grass growth leading to a better nutritional condition and high retention of organic carbon in the food web members during the rainy season when river influence increases. However, the great star coral Montastrea cavernosa nutritional condition decreased significantly. The nearest river to the Reef System was polluted in the dry season; however, a dilution effect was detected in the rainy season, when some coral reefs were contaminated. In 2013, a new treatment plant started working in the area. We would suggest monitoring δ15N and the C: N ratio in macroalgae as indicators of the nitrogen input and coprostanol as an indicator of human feces pollution in order to verify the efficiency of the new treatment plant as part of the management program of the Reef System.

Using the urtA Gene to Profile Nitrogen Stress Adaptation and Spatio-Temporal Abundance of Synechococcus Clades in the California Current System

NASA Astrophysics Data System (ADS)

Chatterjee, T.; Shilova, I. N.; Zehr, J. P.

2015-12-01

Among the planet's most abundant photosynthetic groups, the picocyanobacteria Synechococcus contributes nearly a quarter of our global oxygen supply. Urea, from both natural and anthropogenic sources, is an important alternative to the preferred yet limited sources of reduced nitrogen for cyanobacteria in the marine environment. While urea uptake activity has been observed during nitrogen (N) limitation, this stress adaptation is not well-studied in natural habitats. We propose the urtAgene, which encodes the substrate-binding subunit of the urea-uptake ABC transporter, as a molecular marker to profile cell abundance and stress response in relation to N fluctuation. Strains prevalent in temperate waters of the California Current System - Synechococcus CC9311 (clade I), CC9605 (clade II) and CC9902/BL107 (clade IV) - were targeted by clade-specific qPCR assays to measure urtA gene copy abundance in samples from different geographical stations and a time-series. Spatial and seasonal patterns in clade abundance resembled those previously reported by studies using other Synechococcus marker genes, thus validating urtA as a strong marker. Synechococcus clades I and IV were most abundant in coastal and transitional stations, while the more oligotrophic clade II was detected near open waters. Synechococcus abundances were highest before and after the annual upwelling season, as supported by a non clade-specific rbcL-qPCR assay. A lack of correlation between abundance and nitrate availability indicated utilization of alternative nitrogen sources like urea, which was further evidenced by the detection of clade IV urtA transcripts at the station closest to shore. Urea concentrations tend to be highest in coastal environments due to fertilizer runoff, which can stimulate phytoplankton blooms including harmful algal blooms. This study adds to insight on how such environmental factors are related to N-cycling and patterns of urea-assimilating microbial populations like Synechococcus subgroups in the California Current waters of the Pacific Ocean.

Nonpoint and Point Sources of Nitrogen in Major Watersheds of the United States

USGS Publications Warehouse

Puckett, Larry J.

1994-01-01

Estimates of nonpoint and point sources of nitrogen were made for 107 watersheds located in the U.S. Geological Survey's National Water-Quality Assessment Program study units throughout the conterminous United States. The proportions of nitrogen originating from fertilizer, manure, atmospheric deposition, sewage, and industrial sources were found to vary with climate, hydrologic conditions, land use, population, and physiography. Fertilizer sources of nitrogen are proportionally greater in agricultural areas of the West and the Midwest than in other parts of the Nation. Animal manure contributes large proportions of nitrogen in the South and parts of the Northeast. Atmospheric deposition of nitrogen is generally greatest in areas of greatest precipitation, such as the Northeast. Point sources (sewage and industrial) generally are predominant in watersheds near cities, where they may account for large proportions of the nitrogen in streams. The transport of nitrogen in streams increases as amounts of precipitation and runoff increase and is greatest in the Northeastern United States. Because no single nonpoint nitrogen source is dominant everywhere, approaches to control nitrogen must vary throughout the Nation. Watershed-based approaches to understanding nonpoint and point sources of contamination, as used by the National Water-Quality Assessment Program, will aid water-quality and environmental managers to devise methods to reduce nitrogen pollution.

Bias in bonding behavior among boron, carbon, and nitrogen atoms in ion implanted a-BN, a-BC, and diamond like carbon films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Genisel, Mustafa Fatih; Uddin, Md. Nizam; Say, Zafer

2011-10-01

In this study, we implanted N{sup +} and N{sub 2}{sup +} ions into sputter deposited amorphous boron carbide (a-BC) and diamond like carbon (DLC) thin films in an effort to understand the chemical bonding involved and investigate possible phase separation routes in boron carbon nitride (BCN) films. In addition, we investigated the effect of implanted C{sup +} ions in sputter deposited amorphous boron nitride (a-BN) films. Implanted ion energies for all ion species were set at 40 KeV. Implanted films were then analyzed using x-ray photoelectron spectroscopy (XPS). The changes in the chemical composition and bonding chemistry due to ion-implantationmore » were examined at different depths of the films using sequential ion-beam etching and high resolution XPS analysis cycles. A comparative analysis has been made with the results from sputter deposited BCN films suggesting that implanted nitrogen and carbon atoms behaved very similar to nitrogen and carbon atoms in sputter deposited BCN films. We found that implanted nitrogen atoms would prefer bonding to carbon atoms in the films only if there is no boron atom in the vicinity or after all available boron atoms have been saturated with nitrogen. Implanted carbon atoms also preferred to either bond with available boron atoms or, more likely bonded with other implanted carbon atoms. These results were also supported by ab-initio density functional theory calculations which indicated that carbon-carbon bonds were energetically preferable to carbon-boron and carbon-nitrogen bonds.« less

Regulation of Nitrogen Metabolism by GATA Zinc Finger Transcription Factors in Yarrowia lipolytica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pomraning, Kyle R.; Bredeweg, Erin L.; Baker, Scott E.

ABSTRACT Fungi accumulate lipids in a manner dependent on the quantity and quality of the nitrogen source on which they are growing. In the oleaginous yeastYarrowia lipolytica, growth on a complex source of nitrogen enables rapid growth and limited accumulation of neutral lipids, while growth on a simple nitrogen source promotes lipid accumulation in large lipid droplets. Here we examined the roles of nitrogen catabolite repression and its regulation by GATA zinc finger transcription factors on lipid metabolism inY. lipolytica. Deletion of the GATA transcription factor genesgzf3andgzf2resulted in nitrogen source-specific growth defects and greater accumulation of lipids when the cells weremore » growing on a simple nitrogen source. Deletion ofgzf1, which is most similar to activators of genes repressed by nitrogen catabolite repression in filamentous ascomycetes, did not affect growth on the nitrogen sources tested. We examined gene expression of wild-type and GATA transcription factor mutants on simple and complex nitrogen sources and found that expression of enzymes involved in malate metabolism, beta-oxidation, and ammonia utilization are strongly upregulated on a simple nitrogen source. Deletion ofgzf3results in overexpression of genes with GATAA sites in their promoters, suggesting that it acts as a repressor, whilegzf2is required for expression of ammonia utilization genes but does not grossly affect the transcription level of genes predicted to be controlled by nitrogen catabolite repression. Both GATA transcription factor mutants exhibit decreased expression of genes controlled by carbon catabolite repression via the repressormig1, including genes for beta-oxidation, highlighting the complex interplay between regulation of carbon, nitrogen, and lipid metabolism. IMPORTANCENitrogen source is commonly used to control lipid production in industrial fungi. Here we identified regulators of nitrogen catabolite repression in the oleaginous yeastY. lipolyticato determine how the nitrogen source regulates lipid metabolism. We show that disruption of both activators and repressors of nitrogen catabolite repression leads to increased lipid accumulation via activation of carbon catabolite repression through an as yet uncharacterized method.« less

GOM Deepwater Horizon Oil Spill: A Time Series Analysis of Variations in Spilled Hydrocarbons

NASA Astrophysics Data System (ADS)

Palomo, C. M.; Yan, B.

2013-12-01

An estimated amount of 210 million gallons of crude oil was released into the Gulf of Mexico (GOM) from April 20th to July 15th 2010 during the Deepwater Horizon oil rig explosion. The spill caused a tremendous financial, ecological, environmental and health impact and continues to affect the GOM today. Variations in hydrocarbons including alkanes, hopanes and poly-cyclic aromatic hydrocarbons (PAHs) can be analyzed to better understand the oil spill and assist in oil source identification. Twenty-one sediment samples*, two tar ball samples and one surface water oil sample were obtained from distinct locations in the GOM and within varying time frames from May to December 2010. Each sample was extracted through the ASE 200 solvent extractor, concentrated down under nitrogen gas, purified through an alumina column, concentrated down again with nitrogen gas and analyzed via GC X GC-TOF MS. Forty-one different hydrocarbons were quantified in each sample. Various hydrocarbon 'fingerprints,' such as parental :alkylate PAH ratios, high molecular weight PAHs: low molecular weight alkane ratios, and carbon preference index were calculated. The initial objective of this project was to identify the relative hydrocarbon contributions of petrogenic sources and combustion sources. Based on the calculated ratios, it is evident that the sediment core taken in October of 2010 was greatly affected by combustion sources. Following the first month of the spill, oil in the gulf was burned in attempts to contain the spill. Combustion related sources have quicker sedimentation rates, and hydrocarbons from a combustion source essentially move into deeper depths quicker than those from a petrogenic source, as was observed in analyses of the October 2010 sediment. *Of the twenty-one sediment samples prepared, nine were quantified for this project.

Laboratory Photoionization Fronts in Nitrogen Gas: A Numerical Feasibility and Parameter Study

NASA Astrophysics Data System (ADS)

Gray, William J.; Keiter, P. A.; Lefevre, H.; Patterson, C. R.; Davis, J. S.; van Der Holst, B.; Powell, K. G.; Drake, R. P.

2018-05-01

Photoionization fronts play a dominant role in many astrophysical situations but remain difficult to achieve in a laboratory experiment. We present the results from a computational parameter study evaluating the feasibility of the photoionization experiment presented in the design paper by Drake et al. in which a photoionization front is generated in a nitrogen medium. The nitrogen gas density and the Planckian radiation temperature of the X-ray source define each simulation. Simulations modeled experiments in which the X-ray flux is generated by a laser-heated gold foil, suitable for experiments using many kJ of laser energy, and experiments in which the flux is generated by a “z-pinch” device, which implodes a cylindrical shell of conducting wires. The models are run using CRASH, our block-adaptive-mesh code for multimaterial radiation hydrodynamics. The radiative transfer model uses multigroup, flux-limited diffusion with 30 radiation groups. In addition, electron heat conduction is modeled using a single-group, flux-limited diffusion. In the theory, a photoionization front can exist only when the ratios of the electron recombination rate to the photoionization rate and the electron-impact ionization rate to the recombination rate lie in certain ranges. These ratios are computed for several ionization states of nitrogen. Photoionization fronts are found to exist for laser-driven models with moderate nitrogen densities (∼1021 cm‑3) and radiation temperatures above 90 eV. For “z-pinch”-driven models, lower nitrogen densities are preferred (<1021 cm‑3). We conclude that the proposed experiments are likely to generate photoionization fronts.

Preliminary assessment of sources of nitrogen in groundwater at a biosolids-application area near Deer Trail

USGS Publications Warehouse

Yager, Tracy J.B.; McMahon, Peter B.

2012-01-01

Concentrations of dissolved nitrite plus nitrate increased fairly steadily in samples from four shallow groundwater monitoring wells after biosolids applications to nonirrigated farmland began in 1993. The U.S. Geological Survey began a preliminary assessment of sources of nitrogen in shallow groundwater at part of the biosolids-application area near Deer Trail, Colorado, in 2005 in cooperation with the Metro Wastewater Reclamation District. Possible nitrogen sources in the area include biosolids, animal manure, inorganic fertilizer, atmospheric deposition, and geologic materials (bedrock and soil). Biosolids from the Metro Wastewater Reclamation District plant in Denver and biosolids, cow manure, geologic materials (bedrock and soil), and groundwater from the study area were sampled to measure nitrogen content and nitrogen isotopic compositions of nitrate or total nitrogen. Biosolids also were leached, and the leachates were analyzed for nitrogen content and other concentrations. Geologic materials from the study area also were sampled to determine mineralogy. Estimates of nitrogen contributed from inorganic fertilizer and atmospheric deposition were calculated from other published reports. The nitrogen information from the study indicates that each of the sources contain sufficient nitrogen to potentially affect groundwater nitrate concentrations. Natural processes can transform the nitrogen in any of the sources to nitrate in the groundwater. Load calculations indicate that animal manure, inorganic fertilizer, or atmospheric deposition could have contributed the largest nitrogen load to the study area in the 13 years before biosolids applications began, but biosolids likely contributed the largest nitrogen load to the study area in the 13 years after biosolids applications began. Various approaches provided insights into sources of nitrate in the groundwater samples from 2005. The isotopic data indicate that, of the source materials considered, biosolids and (or) animal manure were the most likely sources of nitrate in the wells at the time of sampling (2005), and that inorganic fertilizer, atmospheric deposition, and geologic materials were not substantial sources of nitrate in the wells in 2005. The large total nitrogen content of the biosolids and animal-manure samples and biosolids leachates also indicates that the biosolids and animal manure had potential to leach nitrogen and produce large dissolved nitrate concentrations in groundwater. The available data, however, could not be used to distinguish between biosolids or manure as the dominant source of nitrate in the groundwater because the nitrogen isotopic composition of the two materials is similar. Major-ion data also could not be used to distinguish between biosolids or manure as the dominant source of nitrate in the groundwater because the major-ion composition (as well as the isotopic composition) of the two materials is similar. Without additional data, chloride/bromide mass ratios do not necessarily support or refute the hypothesis that biosolids and (or) animal manure were the primary sources of nitrate in water from the study-area wells in 2005. Concentrations of water-extractable nitrate in the soil indicate that biosolids could be an important source of nitrate in the groundwater recharge. Nitrogen inventories in the soil beneath biosolids-application areas and the nitrogen-input estimates for the study area both support the comparisons of isotopic composition, which indicate that some type of human waste (such as biosolids) and (or) animal manure was the source of nitrate in groundwater sampled from the wells in 2005. The nitrogen-load estimates considered with the nitrogen isotopic data and the soil-nitrogen inventories indicate that biosolids applications likely are a major source of nitrogen to the shallow groundwater at these monitoring wells.

Characterization of the N2O isotopic composition (15N, 18O and N2O isotopomers) emitted from incubated Amazon forest soils. Implications for the global N2O isotope budget

NASA Astrophysics Data System (ADS)

Pérez, T.; García, D.; Trumbore, S.; Tyler, S.; de Camargo, P.; Moreira, M.; Piccolo, M.; Park, S.; Boering, K.; Cerri, C.

2003-04-01

Tropical rain forest soils are the largest natural source of N2O to the atmosphere. Uncertainty in the signature of this source limits the utility of isotopes in constraining the global N2O budget. Differentiating the relative contribution of nitrification and denitrification to the emitted N2O using stable isotopes has been difficult due to the lack of enrichment factors values for each process measured in situ. We have devised a method for measuring enrichment factors using soil incubation experiments. We selected three Amazon rain forest soils: (1) Clay and (2) Sandy from Santarem, Pará State, and (3) Sandy from Nova Vida Farm, Rondonia State, Brazil. The enrichment factor values for nitrification and denitrification are: -97.8±4.2 and -9.9±3.8 per mil for clay Santarem soil, -86.8±4.3 and -45.2±4.5 per mil for sandy Santarem soil and-112.6±3.8 and -10.4±3.5 per mil for Nova Vida Farm soils, respectively. Our results show that enrichment factors for both processes differ with soil texture and location. The enrichment factors for nitrification are significantly smaller than the range reported in the literature (-66 to -42 per mil). Also, the enrichment factors for the Santarem soils (clay and sandy) differ significantly implying that soil texture (which will affect the soil air filled pore space at a given water content) is influencing the bacteria isotopic discrimination. However, the enrichment factors for the Santarem clay sand Nova Vida sandy soils do not differ by much. This suggests that the enrichment factors not only can be affected by texture but also by the microbial fauna present in these soils. We also determined the measurement of the N2O positional dependence. N2O is a linear molecule with two nitrogen atoms. The 15N isotope can be located in either the central nitrogen (alpha position) or in the terminal nitrogen (beta position). The isotopomer site preference (15N alpha - 15N beta) can be used to differentiate processes of production and consumption of N2O as a potential method to determine the contributions of nitrification and denitrification. We measured the isotopomer composition of the incubated soils and calculated the site preference of each process for each soils. The site preference for nitrification and denitrification are: -114.5 and 56.6 per mil for clay Santarem soil, -75.2 and 11.8 per mil for sandy Santarem soil and -209.7 and 28.8 per mil for Nova Vida Farm soils, respectively. To our knowledge these are the first N2O isotopomer characterizations for nitrification and denitrification in soils. The results show that nitrifying bacteria population has 15N site preference fingerprints smaller by up to 200 per mil than denitrifying bacteria. This data set strongly suggests that N2O isotopomers can be used in concert with traditional N2O stable isotope measurements as constraints to differentiate microbial processes producing N2O. We can conclude that nitrifiers produce N2O with a smaller site preference values and more negative del 15N beta than do denitrifiers. These results show a new proxy to differentiate N2O formation processes in soil and will contribute to produce interpretations of the site preference isotopomeric N2O values found in the troposphere.

Regulation of nitrogen metabolism by GATA zinc finger transcription factors in Yarrowia lipolytica

DOE PAGES

Pomraning, Kyle R.; Bredeweg, Erin L.; Baker, Scott E.; ...

2017-02-15

Here, fungi accumulate lipids in a manner dependent on the quantity and quality of the nitrogen source on which they are growing. In the oleaginous yeast Yarrowia lipolytica, growth on a complex source of nitrogen enables rapid growth and limited accumulation of neutral lipids, while growth on a simple nitrogen source promotes lipid accumulation in large lipid droplets. Here we examined the roles of nitrogen catabolite repression and its regulation by GATA zinc finger transcription factors on lipid metabolism in Y. lipolytica. Deletion of the GATA transcription factor genes gzf3 and gzf2 resulted in nitrogen source-specific growth defects and greatermore » accumulation of lipids when the cells were growing on a simple nitrogen source. Deletion of gzf1, which is most similar to activators of genes repressed by nitrogen catabolite repression in filamentous ascomycetes, did not affect growth on the nitrogen sources tested. We examined gene expression of wild-type and GATA transcription factor mutants on simple and complex nitrogen sources and found that expression of enzymes involved in malate metabolism, beta-oxidation, and ammonia utilization are strongly upregulated on a simple nitrogen source. Deletion of gzf3 results in overexpression of genes with GATAA sites in their promoters, suggesting that it acts as a repressor, while gzf2 is required for expression of ammonia utilization genes but does not grossly affect the transcription level of genes predicted to be controlled by nitrogen catabolite repression. Both GATA transcription factor mutants exhibit decreased expression of genes controlled by carbon catabolite repression via the repressor mig1, including genes for beta-oxidation, highlighting the complex interplay between regulation of carbon, nitrogen, and lipid metabolism.« less

Regulation of nitrogen metabolism by GATA zinc finger transcription factors in Yarrowia lipolytica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pomraning, Kyle R.; Bredeweg, Erin L.; Baker, Scott E.

Here, fungi accumulate lipids in a manner dependent on the quantity and quality of the nitrogen source on which they are growing. In the oleaginous yeast Yarrowia lipolytica, growth on a complex source of nitrogen enables rapid growth and limited accumulation of neutral lipids, while growth on a simple nitrogen source promotes lipid accumulation in large lipid droplets. Here we examined the roles of nitrogen catabolite repression and its regulation by GATA zinc finger transcription factors on lipid metabolism in Y. lipolytica. Deletion of the GATA transcription factor genes gzf3 and gzf2 resulted in nitrogen source-specific growth defects and greatermore » accumulation of lipids when the cells were growing on a simple nitrogen source. Deletion of gzf1, which is most similar to activators of genes repressed by nitrogen catabolite repression in filamentous ascomycetes, did not affect growth on the nitrogen sources tested. We examined gene expression of wild-type and GATA transcription factor mutants on simple and complex nitrogen sources and found that expression of enzymes involved in malate metabolism, beta-oxidation, and ammonia utilization are strongly upregulated on a simple nitrogen source. Deletion of gzf3 results in overexpression of genes with GATAA sites in their promoters, suggesting that it acts as a repressor, while gzf2 is required for expression of ammonia utilization genes but does not grossly affect the transcription level of genes predicted to be controlled by nitrogen catabolite repression. Both GATA transcription factor mutants exhibit decreased expression of genes controlled by carbon catabolite repression via the repressor mig1, including genes for beta-oxidation, highlighting the complex interplay between regulation of carbon, nitrogen, and lipid metabolism.« less

A nitrogen response pathway regulates virulence in plant pathogenic fungi: role of TOR and the bZIP protein MeaB.

PubMed

López-Berges, Manuel S; Rispail, Nicolas; Prados-Rosales, Rafael C; Di Pietro, Antonio

2010-12-01

Virulence in plant pathogenic fungi is controlled through a variety of cellular pathways in response to the host environment. Nitrogen limitation has been proposed to act as a key signal to trigger the in planta expression of virulence genes. Moreover, a conserved Pathogenicity mitogen activated protein kinase (MAPK) cascade is strictly required for plant infection in a wide range of pathogens. We investigated the relationship between nitrogen signaling and the Pathogenicity MAPK cascade in controlling infectious growth of the vascular wilt fungus Fusarium oxysporum. Several MAPK-activated virulence functions such as invasive growth, vegetative hyphal fusion and host adhesion were strongly repressed in the presence of the preferred nitrogen source ammonium. Repression of these functions by ammonium was abolished by L-Methionine sulfoximine (MSX) or rapamycin, two specific inhibitors of Gln synthetase and the protein kinase TOR (Target Of Rapamycin), respectively, and was dependent on the bZIP protein MeaB. Supplying tomato plants with ammonium rather than nitrate resulted in a significant delay of vascular wilt symptoms caused by the F. oxysporum wild type strain, but not by the ΔmeaB mutant. Ammonium also repressed invasive growth in two other pathogens, the rice blast fungus Magnaporthe oryzae and the wheat head blight pathogen Fusarium graminearum. Our results suggest the presence of a conserved nitrogen-responsive pathway that operates via TOR and MeaB to control infectious growth in plant pathogenic fungi.

Effect of nitrogen source on curdlan production by Alcaligenes faecalis ATCC 31749.

PubMed

Jiang, Longfa

2013-01-01

This study aims to investigate the effect of nitrogen source on curdlan production by Alcaligenes faecalis ATCC 31749. Curdlan production fell when excess nitrogen source was present, while biomass accumulation increased as the level of nitrogen source raised. Curdlan production and biomass accumulation were greater with urea compared with those with other nitrogen sources. The highest production of curdlan and biomass accumulation by A. faecalis ATCC 31749 was 28.16 g L(-1) and 9.58 g L(-1), respectively, with urea, whereas those with NH(4)Cl were 15.17 g L(-1) and 6.25 g L(-1), respectively. The optimum fermentation time for curdlan production was also affected by the nitrogen source in the medium. Copyright © 2012 Elsevier B.V. All rights reserved.

[Research advances in identifying nitrate pollution sources of water environment by using nitrogen and oxygen stable isotopes].

PubMed

Mao, Wei; Liang, Zhi-wei; Li, Wei; Zhu, Yao; Yanng, Mu-yi; Jia, Chao-jie

2013-04-01

Water body' s nitrate pollution has become a common and severe environmental problem. In order to ensure human health and water environment benign evolution, it is of great importance to effectively identify the nitrate pollution sources of water body. Because of the discrepant composition of nitrogen and oxygen stable isotopes in different sources of nitrate in water body, nitrogen and oxygen stable isotopes can be used to identify the nitrate pollution sources of water environment. This paper introduced the fractionation factors of nitrogen and oxygen stable isotopes in the main processes of nitrogen cycling and the composition of these stable isotopes in main nitrate sources, compared the advantages and disadvantages of five pre-treatment methods for analyzing the nitrogen and oxygen isotopes in nitrate, and summarized the research advances in this aspect into three stages, i. e. , using nitrogen stable isotope alone, using nitrogen and oxygen stable isotopes simultaneously, and combining with mathematical models. The future research directions regarding the nitrate pollution sources identification of water environment were also discussed.

Effects of different nitrogen sources on the biogas production - a lab-scale investigation.

PubMed

Wagner, Andreas Otto; Hohlbrugger, Peter; Lins, Philipp; Illmer, Paul

2012-12-20

For anaerobic digestion processes nitrogen sources are poorly investigated although they are known as possible process limiting factors (in the hydrolysis phase) but also as a source for fermentations for subsequent methane production by methanogenic archaea. In the present study different complex and defined nitrogen sources were investigated in a lab-scale experiment in order to study their potential to build up methane. The outcome of the study can be summarised as follows: from complex nitrogen sources yeast extract and casamino acids showed the highest methane production with approximately 600 ml methane per mole of nitrogen, whereas by the use of skim milk no methane production could be observed. From defined nitrogen sources L-arginine showed the highest methane production with almost 1400 ml methane per mole of nitrogen. Moreover it could be demonstrated that the carbon content and therefore C/N-ratio has only minor influence for the methane production from the used substrates. Copyright © 2011 Elsevier GmbH. All rights reserved.

Analyzing the contribution of climate change to long-term variations in sediment nitrogen sources for reservoirs/lakes.

PubMed

Xia, Xinghui; Wu, Qiong; Zhu, Baotong; Zhao, Pujun; Zhang, Shangwei; Yang, Lingyan

2015-08-01

We applied a mixing model based on stable isotopic δ(13)C, δ(15)N, and C:N ratios to estimate the contributions of multiple sources to sediment nitrogen. We also developed a conceptual model describing and analyzing the impacts of climate change on nitrogen enrichment. These two models were conducted in Miyun Reservoir to analyze the contribution of climate change to the variations in sediment nitrogen sources based on two (210)Pb and (137)Cs dated sediment cores. The results showed that during the past 50years, average contributions of soil and fertilizer, submerged macrophytes, N2-fixing phytoplankton, and non-N2-fixing phytoplankton were 40.7%, 40.3%, 11.8%, and 7.2%, respectively. In addition, total nitrogen (TN) contents in sediment showed significant increasing trends from 1960 to 2010, and sediment nitrogen of both submerged macrophytes and phytoplankton sources exhibited significant increasing trends during the past 50years. In contrast, soil and fertilizer sources showed a significant decreasing trend from 1990 to 2010. According to the changing trend of N2-fixing phytoplankton, changes of temperature and sunshine duration accounted for at least 43% of the trend in the sediment nitrogen enrichment over the past 50years. Regression analysis of the climatic factors on nitrogen sources showed that the contributions of precipitation, temperature, and sunshine duration to the variations in sediment nitrogen sources ranged from 18.5% to 60.3%. The study demonstrates that the mixing model provides a robust method for calculating the contribution of multiple nitrogen sources in sediment, and this study also suggests that N2-fixing phytoplankton could be regarded as an important response factor for assessing the impacts of climate change on nitrogen enrichment. Copyright © 2015 Elsevier B.V. All rights reserved.

The influence of different nitrogen and carbon sources on mycotoxin production in Alternaria alternata.

PubMed

Brzonkalik, Katrin; Herrling, Tanja; Syldatk, Christoph; Neumann, Anke

2011-05-27

The aim of this study was to determine the influence of different carbon and nitrogen sources on the production of the mycotoxins alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) by Alternaria alternata at 28°C using a semi-synthetic medium (modified Czapek-Dox broth) supplemented with nitrogen and carbon sources. Additionally the effect of shaken and static cultivation on mycotoxin production was tested. Initial experiments showed a clear dependency between nitrogen depletion and mycotoxin production. To assess whether nitrogen limitation in general or the type of nitrogen source triggers the production, various nitrogen sources including several ammonium/nitrate salts and amino acids were tested. In static culture the production of AOH/AME can be enhanced greatly with phenylalanine whereas some nitrogen sources seem to inhibit the AOH/AME production completely. TA was not significantly affected by the choice of nitrogen source. In shaken culture the overall production of all mycotoxins was lower compared to static cultivation. Furthermore tests with a wide variety of carbon sources including monosaccharides, disaccharides, complex saccharides such as starch as well as glycerol and acetate were performed. In shaken culture AOH was produced when glucose, fructose, sucrose, acetate or mixtures of glucose/sucrose and glucose/acetate were used as carbon sources. AME production was not detected. The use of sodium acetate resulted in the highest AOH production. In static culture AOH production was also stimulated by acetate and the amount is comparable to shaken conditions. Under static conditions production of AOH was lower except when cultivated with acetate. In static cultivation 9 of 14 tested carbon sources induced mycotoxin production compared to 4 in shaken culture. This is the first study which analyses the influence of carbon and nitrogen sources in a semi-synthetic medium and assesses the effects of culture conditions on mycotoxin production by A. alternata. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of nitrogen and carbon sources on the production of inulinase from strain Bacillus sp. SG113

NASA Astrophysics Data System (ADS)

Gavrailov, Simeon; Ivanova, Viara

2016-03-01

The effects of the carbon and nitrogen substrates on the growth of Bacillus sp. SG113 strain were studied. The use of organic nitrogen sources (peptone, beef extract, yeast extract, casein) leads to rapid cellular growth and the best results for the Bacillus strain were obtained with casein hydrolysate. From the inorganic nitrogen sources studied, the (NH4) 2SO4 proved to be the best nitrogen source. Casein hydrolysate and (NH4) 2SO4 stimulated the invertase synthesis. In the presence of Jerusalem artichoke, onion and garlic extracts as carbon sources the strain synthesized from 6 to 10 times more inulinase.

Atmospheric Nitrogen Deposition in the Western United States: Sources, Sinks and Changes over Time

NASA Astrophysics Data System (ADS)

Anderson, Sarah Marie

Anthropogenic activities have greatly modified the way nitrogen moves through the atmosphere and terrestrial and aquatic environments. Excess reactive nitrogen generated through fossil fuel combustion, industrial fixation, and intensification of agriculture is not confined to anthropogenic systems but leaks into natural ecosystems with consequences including acidification, eutrophication, and biodiversity loss. A better understanding of where excess nitrogen originates and how that changes over time is crucial to identifying when, where, and to what degree environmental impacts occur. A major route into ecosystems for excess nitrogen is through atmospheric deposition. Excess nitrogen is emitted to the atmosphere where it can be transported great distances before being deposited back to the Earth's surface. Analyzing the composition of atmospheric nitrogen deposition and biological indicators that reflect deposition can provide insight into the emission sources as well as processes and atmospheric chemistry that occur during transport and what drives variation in these sources and processes. Chapter 1 provides a review and proof of concept of lichens to act as biological indicators and how their elemental and stable isotope composition can elucidate variation in amounts and emission sources of nitrogen over space and time. Information on amounts and emission sources of nitrogen deposition helps inform natural resources and land management decisions by helping to identify potentially impacted areas and causes of those impacts. Chapter 2 demonstrates that herbaria lichen specimens and field lichen samples reflect historical changes in atmospheric nitrogen deposition from urban and agricultural sources across the western United States. Nitrogen deposition increases throughout most of the 20 th century because of multiple types of emission sources until the implementation of the Clean Air Act Amendments of 1990 eventually decrease nitrogen deposition around the turn of the 21st century. Chapter 3 focuses on how nitrogen emissions and subsequent deposition are affected by processes and chemistry during atmospheric transport through analysis of the oxygen isotope composition of nitrate in wet deposition. Local emission sources drive spatial variation, changes in solar radiation drive seasonal variation, and variability in atmospheric conditions and transport drive interannual variation in the processes and chemistry occurring during atmospheric transport of reactive nitrogen.

Fire and nitrogen fertilization effects on Purple Threeawn in vitro fermentation and gas production

USDA-ARS?s Scientific Manuscript database

Purple threeawn (Aristida purpurea) is a native perennial bunchgrass with poor forage quality. The grass often dominates sites where soils have been disturbed and persists with continued severe grazing of preferred species due to livestock avoidance of threeawn. Nitrogen fertilization and fire hav...

Distinguishing nitrous oxide production from nitrification and denitrification on the basis of isotopomer abundances.

PubMed

Sutka, R L; Ostrom, N E; Ostrom, P H; Breznak, J A; Gandhi, H; Pitt, A J; Li, F

2006-01-01

The intramolecular distribution of nitrogen isotopes in N2O is an emerging tool for defining the relative importance of microbial sources of this greenhouse gas. The application of intramolecular isotopic distributions to evaluate the origins of N2O, however, requires a foundation in laboratory experiments in which individual production pathways can be isolated. Here we evaluate the site preferences of N2O produced during hydroxylamine oxidation by ammonia oxidizers and by a methanotroph, ammonia oxidation by a nitrifier, nitrite reduction during nitrifier denitrification, and nitrate and nitrite reduction by denitrifiers. The site preferences produced during hydroxylamine oxidation were 33.5 +/- 1.2 per thousand, 32.5 +/- 0.6 per thousand, and 35.6 +/- 1.4 per thousand for Nitrosomonas europaea, Nitrosospira multiformis, and Methylosinus trichosporium, respectively, indicating similar site preferences for methane and ammonia oxidizers. The site preference of N2O from ammonia oxidation by N. europaea (31.4 +/- 4.2 per thousand) was similar to that produced during hydroxylamine oxidation (33.5 +/- 1.2 per thousand) and distinct from that produced during nitrifier denitrification by N. multiformis (0.1 +/- 1.7 per thousand), indicating that isotopomers differentiate between nitrification and nitrifier denitrification. The site preferences of N2O produced during nitrite reduction by the denitrifiers Pseudomonas chlororaphis and Pseudomonas aureofaciens (-0.6 +/- 1.9 per thousand and -0.5 +/- 1.9 per thousand, respectively) were similar to those during nitrate reduction (-0.5 +/- 1.9 per thousand and -0.5 +/- 0.6 per thousand, respectively), indicating no influence of either substrate on site preference. Site preferences of approximately 33 per thousand and approximately 0 per thousand are characteristic of nitrification and denitrification, respectively, and provide a basis to quantitatively apportion N2O.

A series of inorganic solid nitrogen sources for the synthesis of metal nitride clusterfullerenes: the dependence of production yield on the oxidation state of nitrogen and counter ion.

PubMed

Liu, Fupin; Guan, Jian; Wei, Tao; Wang, Song; Jiao, Mingzhi; Yang, Shangfeng

2013-04-01

A series of nitrogen-containing inorganic solid compounds with variable oxidation states of nitrogen and counter ions have been successfully applied as new inorganic solid nitrogen sources toward the synthesis of Sc-based metal nitride clusterfullerenes (Sc-NCFs), including ammonium salts [(NH4)xH(3-x)PO4 (x = 0-2), (NH4)2SO4, (NH4)2CO3, NH4X (X = F, Cl), NH4SCN], thiocyanate (KSCN), nitrates (Cu(NO3)2, NaNO3), and nitrite (NaNO2). Among them, ammonium phosphates ((NH4)xH(3-x)PO4, x = 1-3) and ammonium thiocyanate (NH4SCN) are revealed to behave as better nitrogen sources than others, and the highest yield of Sc-NCFs is achieved when NH4SCN was used as a nitrogen source. The optimum molar ratio of Sc2O3:(NH4)3PO4·3H2O:C and Sc2O3:NH4SCN:C has been determined to be 1:2:15 and 1:3:15, respectively. The thermal decomposition products of these 12 inorganic compounds have been discussed in order to understand their different performances toward the synthesis of Sc-NCFs, and accordingly the dependence of the production yield of Sc-NCFs on the oxidation state of nitrogen and counter ion is interpreted. The yield of Sc3N@C80 (I(h) + D(5h)) per gram Sc2O3 by using the N2-based group of nitrogen sources (thiocyanate, nitrates, and nitrite) is overall much lower than those by using gaseous N2 and NH4SCN, indicating the strong dependence of the yield of Sc-NCFs on the oxidation state of nitrogen, which is attributed to the "in-situ" redox reaction taking place for the N2-based group of nitrogen sources during discharging. For NH3-based group of nitrogen sources (ammonium salts) which exhibits a (-3) oxidation states of nitrogen, their performance as nitrogen sources is found to be sensitively dependent on the anion, and this is understood by considering their difference on the thermal stability and/or decomposition rate. Contrarily, for the N2-based group of nitrogen sources, the formation of Sc-NCFs is independent to both the oxidation state of nitrogen (+3 or +5) and the cation.

Nitrogen Source Stabilization of Quorum Sensing in the Pseudomonas aeruginosa Bioaugmentation Strain SD-1.

PubMed

Wang, Mei-Zhen; Lai, Bai-Min; Dandekar, Ajai A; Yang, Yu-Sheng; Li, Na; Yin, Jun; Shen, Dong-Sheng

2017-08-15

Pseudomonas aeruginosa SD-1 is efficient at degrading aromatic compounds and can therefore contribute to the bioremediation of wastewater. P. aeruginosa uses quorum sensing (QS) to regulate the production of numerous secreted "public goods." In wastewater bioaugmentation applications, there are myriad nitrogen sources, and we queried whether various nitrogen sources impact the stabilities of both QS and the bacterial populations. In a laboratory strain of P. aeruginosa , PAO1, the absence of a nitrogen source has been shown to destabilize these populations through the emergence of QS mutant "cheaters." We tested the ability of SD-1 to grow in casein broth, a condition that requires QS for growth, when the nitrogen source with either NH 4 Cl, NaNO 3 , or NaNO 2 or with no added nitrogen source. There was great variability in susceptibility to invasion by QS mutant cheaters and, by extension, the stability of the SD-1 population. When grown with NH 4 Cl as an extra nitrogen source, no population collapse was observed; by contrast, two-thirds of cultures grown in the presence of NaNO 2 collapsed. In the populations that collapsed, the frequency of social cheaters exceeded 40%. NaNO 3 and NaNO 2 directly favor QS mutants of P. aeruginosa SD-1. Although the mechanism by which these nitrogen sources act is not clear, these data indicate that the metabolism of nitrogen can affect the stability of bacterial populations, an important observation for continuing industrial applications with this species. IMPORTANCE Bioaugmentation as a method to help remediate wastewater pollutant streams holds significant potential to enhance traditional methods of treatment. Addition of microbes that can catabolize organic pollutants can be an effective method to remove several toxic compounds. Such bioaugmented strains of bacteria have been shown to be susceptible to competition from the microbiota that are present in wastewater streams, limiting their potential effectiveness. Here, we show that bioaugmentation strains of bacteria might also be susceptible to invasion by social cheaters and that the nitrogen sources available in the wastewater might influence the ability of cheaters to overtake the bioaugmentation strains. Our results imply that control over the nitrogen sources in a wastewater stream or selective addition of certain nitrogen sources could help stabilize bioaugmentation strains of bacteria. Copyright © 2017 American Society for Microbiology.

Ecofriendly demulsification of water in oil emulsions by an efficient biodemulsifier producing bacterium isolated from oil contaminated environment.

PubMed

Sabati, Hoda; Motamedi, Hossein

2018-05-15

Water in oil emulsions increase oil processing costs and cause damage to refinery equipment which necessitates demulsification. Since chemical demulsifiers cause environmental pollution, biodemulsifiers have been paid more attention. This study aims to identify biodemulsifier-producing bacteria from petroleum contaminated environments. As a result, several biodemulsifier producing strains were found that Stenotrophomonas sp. strain HS7 (accession number: MF445088) which produced a cell associated biodemulsifier showed the highest demulsifying ratio, 98.57% for water in kerosene and 66.28% for water in crude oil emulsion after 48 h. 35 °C, pH 7, 48 h incubation and ammonium nitrate as nitrogen source were optimum conditions for biodemulsifier production. Furthermore, it was found that hydrophobic carbon sources like as liquid paraffin is not preferred as the sole carbon source while a combination of various carbon sources including liquid paraffin will increase demulsification efficiency of the biodemulsifier. The appropriate potential of this biodemulsifier strengthens the possibility of its application in industries especially petroleum industry.

Ectomycorrhizal Fungal Protein Degradation Ability Predicted by Soil Organic Nitrogen Availability

PubMed Central

Stas, Jelle; Nguyen, Nhu H.; Kuyper, Thomas W.; Carleer, Robert; Vangronsveld, Jaco; Colpaert, Jan V.; Kennedy, Peter G.

2015-01-01

In temperate and boreal forest ecosystems, nitrogen (N) limitation of tree metabolism is alleviated by ectomycorrhizal (ECM) fungi. As forest soils age, the primary source of N in soil switches from inorganic (NH4+ and NO3−) to organic (mostly proteins). It has been hypothesized that ECM fungi adapt to the most common N source in their environment, which implies that fungi growing in older forests would have greater protein degradation abilities. Moreover, recent results for a model ECM fungal species suggest that organic N uptake requires a glucose supply. To test the generality of these hypotheses, we screened 55 strains of 13 Suillus species with different ecological preferences for their in vitro protein degradation abilities. Suillus species preferentially occurring in mature forests, where soil contains more organic matter, had significantly higher protease activity than those from young forests with low-organic-matter soils or species indifferent to forest age. Within species, the protease activities of ecotypes from soils with high or low soil organic N content did not differ significantly, suggesting resource partitioning between mineral and organic soil layers. The secreted protease mixtures were strongly dominated by aspartic peptidases. Glucose addition had variable effects on secreted protease activity; in some species, it triggered activity, but in others, activity was repressed at high concentrations. Collectively, our results indicate that protease activity, a key ectomycorrhizal functional trait, is positively related to environmental N source availability but is also influenced by additional factors, such as carbon availability. PMID:26682855

Use of collagen hydrolysate as a complex nitrogen source for the synthesis of penicillin by Penicillium chrysogenum.

PubMed

Leonhartsberger, S; Lafferty, R M; Korneti, L

1993-09-01

Optimal conditions for both biomass formation and penicillin synthesis by a strain of Penicillium chrysogenum were determined when using a collagen-derived nitrogen source. Preliminary investigations were carried out in shaken flask cultures employing a planned experimental program termed the Graeco-Latin square technique (Auden et al., 1967). It was initially determined that up to 30% of a conventional complex nitrogen source such as cottonseed meal could be replaced by the collagen-derived nitrogen source without decreasing the productivity with respect to the penicillin yield. In the pilot scale experiments using a 30 l stirred tank type of bioreactor, higher penicillin yields were obtained when 70% of the conventional complex nitrogen source in the form of cottonseed meal was replaced by the collagen hydrolysate. Furthermore, the maximum rate of penicillin synthesis continued for over a longer period when using collagen hydrolysate as a complex nitrogen source. Penicillin synthesis rates were determined using a linear regression.

Porphyromonas endodontalis binds, reduces and grows on human hemoglobin.

PubMed

Zerr, M; Drake, D; Johnson, W; Cox, C D

2001-08-01

Porphyromonas endodontalis is a black-pigmented, obligate anaerobic rod-shaped bacterium implicated as playing a major role in endodontic infections. We have previously shown that P. endodontalis requires the porphyrin nucleus, preferably supplied as hemoglobin, as a growth supplement. The bacteria also actively transport free iron, although this activity does not support growth in the absence of a porphyrin source. The purpose of this study was to further investigate the binding and subsequent utilization of human hemoglobin by P. endodontalis. P. endodontalis binds hemoglobin and reduces the Fe(III) porphyrin, resulting in a steady accumulation of ferrous hemoglobin. Reduction of methemoglobin was similar to the extracellular reduction of nitrobluetetrazolium in the presence of oxidizable substrate. Turbidimetric and viable cell determinations showed that P. endodontalis grew when supplied only hemoglobin. Therefore, we conclude that hemoglobin appears to serve as a sole carbon and nitrogen source, and that these bacteria reduce extracellular compounds at the expense of oxidized substrates.

Highly efficient induction of chirality in intramolecular

PubMed

Cossio; Arrieta; Lecea; Alajarin; Vidal; Tovar

2000-06-16

Highly stereocontrolled, intramolecular [2 + 2] cycloadditions between ketenimines and imines leading to 1,2-dihydroazeto[2, 1-b]quinazolines have been achieved. The source of stereocontrol is a chiral carbon atom adjacent either to the iminic carbon or nitrogen atom. In the first case, the stereocontrol stems from the preference for the axial conformer in the first transition structure. In the second case, the origin of the stereocontrol lies on the two-electron stabilizing interaction between the C-C bond being formed and the sigma orbital corresponding to the polar C-X bond, X being an electronegative atom. These models can be extended to other related systems for predicting the stereochemical outcome in this intramolecular reaction.

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, Larry R.; Post Jr., Douglass E.; Dawson, John M.

1986-06-03

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, Larry R.; Post, Jr., Douglass E.; Dawson, John M.

1986-01-01

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Toward disentangling the effect of hydrologic and nitrogen source changes from 1992 to 2001 on incremental nitrogen yield in the contiguous United States

NASA Astrophysics Data System (ADS)

Alam, Md Jahangir; Goodall, Jonathan L.

2012-04-01

The goal of this research was to quantify the relative impact of hydrologic and nitrogen source changes on incremental nitrogen yield in the contiguous United States. Using nitrogen source estimates from various federal data bases, remotely sensed land use data from the National Land Cover Data program, and observed instream loadings from the United States Geological Survey National Stream Quality Accounting Network program, we calibrated and applied the spatially referenced regression model SPARROW to estimate incremental nitrogen yield for the contiguous United States. We ran different model scenarios to separate the effects of changes in source contributions from hydrologic changes for the years 1992 and 2001, assuming that only state conditions changed and that model coefficients describing the stream water-quality response to changes in state conditions remained constant between 1992 and 2001. Model results show a decrease of 8.2% in the median incremental nitrogen yield over the period of analysis with the vast majority of this decrease due to changes in hydrologic conditions rather than decreases in nitrogen sources. For example, when we changed the 1992 version of the model to have nitrogen source data from 2001, the model results showed only a small increase in median incremental nitrogen yield (0.12%). However, when we changed the 1992 version of the model to have hydrologic conditions from 2001, model results showed a decrease of approximately 8.7% in median incremental nitrogen yield. We did, however, find notable differences in incremental yield estimates for different sources of nitrogen after controlling for hydrologic changes, particularly for population related sources. For example, the median incremental yield for population related sources increased by 8.4% after controlling for hydrologic changes. This is in contrast to a 2.8% decrease in population related sources when hydrologic changes are included in the analysis. Likewise we found that median incremental yield from urban watersheds increased by 6.8% after controlling for hydrologic changes—in contrast to the median incremental nitrogen yield from cropland watersheds, which decreased by 2.1% over the same time period. These results suggest that, after accounting for hydrologic changes, population related sources became a more significant contributor of nitrogen yield to streams in the contiguous United States over the period of analysis. However, this study was not able to account for the influence of human management practices such as improvements in wastewater treatment plants or Best Management Practices that likely improved water quality, due to a lack of data for quantifying the impact of these practices for the study area.

Nitrogen deposition in precipitation to a monsoon-affected eutrophic embayment: Fluxes, sources, and processes

NASA Astrophysics Data System (ADS)

Wu, Yunchao; Zhang, Jingping; Liu, Songlin; Jiang, Zhijian; Arbi, Iman; Huang, Xiaoping; Macreadie, Peter Ian

2018-06-01

Daya Bay in the South China Sea (SCS) has experienced rapid nitrogen pollution and intensified eutrophication in the past decade due to economic development. Here, we estimated the deposition fluxes of nitrogenous species, clarified the contribution of nitrogen from precipitation and measured ions and isotopic composition (δ15N and δ18O) of nitrate in precipitation in one year period to trace its sources and formation processes among different seasons. We found that the deposition fluxes of total dissolved nitrogen (TDN), NO3-, NH4+, NO2-, and dissolved organic nitrogen (DON) to Daya Bay were 132.5, 64.4 17.5, 1.0, 49.6 mmol m-2•yr-1, respectively. DON was a significant contributor to nitrogen deposition (37% of TDN), and NO3- accounted for 78% of the DIN in precipitation. The nitrogen deposition fluxes were higher in spring and summer, and lower in winter. Nitrogen from precipitation contributed nearly 38% of the total input of nitrogen (point sources input and dry and wet deposition) in Daya Bay. The δ15N-NO3- abundance, ion compositions, and air mass backward trajectories implicated that coal combustion, vehicle exhausts, and dust from mainland China delivered by northeast monsoon were the main sources in winter, while fossil fuel combustion (coal combustion and vehicle exhausts) and dust from PRD and southeast Asia transported by southwest monsoon were the main sources in spring; marine sources, vehicle exhausts and lightning could be the potential sources in summer. δ18O results showed that OH pathway was dominant in the chemical formation process of nitrate in summer, while N2O5+ DMS/HC pathways in winter and spring.

Regulation Effects of Water and Nitrogen on the Source-Sink Relationship in Potato during the Tuber Bulking Stage

PubMed Central

Li, Wenting; Xiong, Binglin; Wang, Shiwen; Deng, Xiping; Yin, Lina; Li, Hongbing

2016-01-01

The source-sink relationship determines crop yield, and it is largely regulated by water and nutrients in agricultural production. This has been widely investigated in cereals, but fewer studies have been conducted in root and tuber crops such as potato (Solanum tuberosum L.). The objective of this study was to investigate the source-sink relationship in potato and the regulation of water and nitrogen on the source-sink relationship during the tuber bulking stage. A pot experiment using virus-free plantlets of the Atlantic potato cultivar was conducted, using three water levels (50%, 70% and 90% of field capacity) and three nitrogen levels (0, 0.2, 0.4 g N∙kg−1 soil). The results showed that, under all water and nitrogen levels, plant source capacity were small at the end of the experiment, since photosynthetic activity in leaves were low and non-structural reserves in underground stems were completely remobilized. While at this time, there were very big differences in maximum and minimum tuber number and tuber weight, indicating that the sink tuber still had a large potential capacity to take in assimilates. These results suggest that the source-supplied assimilates were not sufficient enough to meet the demands of sink growth. Thus, we concluded that, unlike cereals, potato yield is more likely to be source-limited than sink-limited during the tuber bulking stage. Water and nitrogen are two key factors in potato production management. Our results showed that water level, nitrogen level and the interaction between water and nitrogen influence potato yield mainly through affecting source capacity via the net photosynthetic rate, total leaf area and leaf life span. Well-watered, sufficient nitrogen and well-watered combined with sufficient nitrogen increased yield mainly by enhancing the source capacity. Therefore, this suggests that increasing source capacity is more crucial to improve potato yield. PMID:26752657

40 CFR Table 9 to Subpart Uuuu of... - Recordkeeping Requirements

Code of Federal Regulations, 2010 CFR

2010-07-01

... process affected source records of nitrogen unloading and storage systems or nitrogen unloading systems records certifying that a nitrogen unloading and storage system or nitrogen unloading system is in use. 9. an existing or new viscose process affected source records of material balances all pertinent data...

40 CFR Table 9 to Subpart Uuuu of... - Recordkeeping Requirements

Code of Federal Regulations, 2012 CFR

2012-07-01

... process affected source records of nitrogen unloading and storage systems or nitrogen unloading systems records certifying that a nitrogen unloading and storage system or nitrogen unloading system is in use. 9. an existing or new viscose process affected source records of material balances all pertinent data...

40 CFR Table 9 to Subpart Uuuu of... - Recordkeeping Requirements

Code of Federal Regulations, 2013 CFR

2013-07-01

... process affected source records of nitrogen unloading and storage systems or nitrogen unloading systems records certifying that a nitrogen unloading and storage system or nitrogen unloading system is in use. 9. an existing or new viscose process affected source records of material balances all pertinent data...

40 CFR Table 9 to Subpart Uuuu of... - Recordkeeping Requirements

Code of Federal Regulations, 2014 CFR

2014-07-01

... process affected source records of nitrogen unloading and storage systems or nitrogen unloading systems records certifying that a nitrogen unloading and storage system or nitrogen unloading system is in use. 9. an existing or new viscose process affected source records of material balances all pertinent data...

40 CFR Table 9 to Subpart Uuuu of... - Recordkeeping Requirements

Code of Federal Regulations, 2011 CFR

2011-07-01

... process affected source records of nitrogen unloading and storage systems or nitrogen unloading systems records certifying that a nitrogen unloading and storage system or nitrogen unloading system is in use. 9. an existing or new viscose process affected source records of material balances all pertinent data...

RIBBED MUSSEL NITROGEN ISOTOPE SIGNATURES REFLECT NITROGEN SOURCES IN COASTAL MARSHES

EPA Science Inventory

The stable nitrogen isotope ratio in tissue of the ribbed mussel (Geukensia demissa) was investigated as an indicator of the source of nitrogen inputs to coastal salt marshes. Initially, mussels were fed a diet of 15N-enriched algae in the laboratory to determine how the tissue n...

'Trophic' and 'source' amino acids in trophic estimation: a likely metabolic explanation.

PubMed

O'Connell, T C

2017-06-01

Amino acid nitrogen isotopic analysis is a relatively new method for estimating trophic position. It uses the isotopic difference between an individual's 'trophic' and 'source' amino acids to determine its trophic position. So far, there is no accepted explanation for the mechanism by which the isotopic signals in 'trophic' and 'source' amino acids arise. Yet without a metabolic understanding, the utility of nitrogen isotopic analyses as a method for probing trophic relations, at either bulk tissue or amino acid level, is limited. I draw on isotopic tracer studies of protein metabolism, together with a consideration of amino acid metabolic pathways, to suggest that the 'trophic'/'source' groupings have a fundamental metabolic origin, to do with the cycling of amino-nitrogen between amino acids. 'Trophic' amino acids are those whose amino-nitrogens are interchangeable, part of a metabolic amino-nitrogen pool, and 'source' amino acids are those whose amino-nitrogens are not interchangeable with the metabolic pool. Nitrogen isotopic values of 'trophic' amino acids will reflect an averaged isotopic signal of all such dietary amino acids, offset by the integrated effect of isotopic fractionation from nitrogen cycling, and modulated by metabolic and physiological effects. Isotopic values of 'source' amino acids will be more closely linked to those of equivalent dietary amino acids, but also modulated by metabolism and physiology. The complexity of nitrogen cycling suggests that a single identifiable value for 'trophic discrimination factors' is unlikely to exist. Greater consideration of physiology and metabolism should help in better understanding observed patterns in nitrogen isotopic values.

Female butterflies adapt and allocate their progeny to the host-plant quality of their own larval experience.

PubMed

Cahenzli, Fabian; Wenk, Barbara A; Erhardt, Andreas

2015-07-01

Recent studies with diverse taxa have shown that parents can utilize their experience of the environment to adapt their offspring's phenotype to the same environmental conditions. Thus, offspring would then perform best under environmental conditions experienced by their parents due to transgenerational phenotypic plasticity. Such an effect has been dubbed transgenerational acclimatization. However, evidence that parents can subsequently ensure the appropriate environmental conditions in order that offspring benefit from transgenerational acclimatization has never been demonstrated. We reared Pieris rapae larvae in the parental generation on high-nitrogen and low-nitrogen host plants, and reared the offspring (F1) of both treatments again on high- and low-nitrogen plants. Furthermore, we tested if females prefer to oviposit on high- or low-nitrogen host plants in two-way choice tests. We here show not only that females adapt their offspring's phenotype to the host-plant quality that they themselves experienced, but that females also mainly oviposit on the host quality to which they adapt their offspring. Moreover, effects of larval host plant on oviposition preference of females increased across two generations in F1-females acclimatized to low-nitrogen host plants, showing an adaptive host shift from one generation to the next. These findings may have profound implications for host-race formation and sympatric speciation.

Biotic Nitrogen Enrichment Regulates Calcium Sources to Forests

NASA Astrophysics Data System (ADS)

Pett-Ridge, J. C.; Perakis, S. S.; Hynicka, J. D.

2015-12-01

Calcium is an essential nutrient in forest ecosystems that is susceptible to leaching loss and depletion. Calcium depletion can affect plant and animal productivity, soil acid buffering capacity, and fluxes of carbon and water. Excess nitrogen supply and associated soil acidification are often implicated in short-term calcium loss from soils, but the long-term role of nitrogen enrichment on calcium sources and resupply is unknown. Here we use strontium isotopes (87Sr/86Sr) as a proxy for calcium to investigate how soil nitrogen enrichment from biological nitrogen fixation interacts with bedrock calcium to regulate both short-term available supplies and the long-term sources of calcium in montane conifer forests. Our study examines 22 sites in western Oregon, spanning a 20-fold range of bedrock calcium on sedimentary and basaltic lithologies. In contrast to previous studies emphasizing abiotic control of weathering as a determinant of long-term ecosystem calcium dynamics and sources (via bedrock fertility, climate, or topographic/tectonic controls) we find instead that that biotic nitrogen enrichment of soil can strongly regulate calcium sources and supplies in forest ecosystems. For forests on calcium-rich basaltic bedrock, increasing nitrogen enrichment causes calcium sources to shift from rock-weathering to atmospheric dominance, with minimal influence from other major soil forming factors, despite regionally high rates of tectonic uplift and erosion that can rejuvenate weathering supply of soil minerals. For forests on calcium-poor sedimentary bedrock, we find that atmospheric inputs dominate regardless of degree of nitrogen enrichment. Short-term measures of soil and ecosystem calcium fertility are decoupled from calcium source sustainability, with fundamental implications for understanding nitrogen impacts, both in natural ecosystems and in the context of global change. Our finding that long-term nitrogen enrichment increases forest reliance on atmospheric calcium helps explain reports of greater ecological calcium limitation in an increasingly nitrogen-rich world.

Dual Nitrate Isotopes in Dry Deposition: Utility for Partitioning Nox Source Contributions to Landscape Nitrogen Deposition

EPA Science Inventory

Dry deposition is a major component of total nitrogen deposition and thus an important source of bioavailable nitrogen to ecosystems. However, relative to wet deposition, less is known regarding the sources and spatial variability of dry deposition. This is in part due to diffi...

Use of corn steep liquor as an economical nitrogen source for biosuccinic acid production by Actinobacillus succinogenes

NASA Astrophysics Data System (ADS)

Tan, J. P.; Jahim, J. M.; Wu, T. Y.; Harun, S.; Mumtaz, T.

2016-06-01

Expensive raw materials are the driving force that leads to the shifting of the petroleum-based succinic acid production into bio-based succinic acid production by microorganisms. Cost of fermentation medium is among the main factors contributing to the total production cost of bio-succinic acid. After carbon source, nitrogen source is the second largest component of the fermentation medium, the cost of which has been overlooked for the past years. The current study aimed at replacing yeast extract- a costly nitrogen source with corn steep liquor for economical production of bio-succinic acid by Actinobacillus succinogenes 130Z. In this study, a final succinic acid concentration of 20.6 g/L was obtained from the use of corn steep liquor as the nitrogen source, which was comparable with the use of yeast extract as the nitrogen source that had a final succinate concentration of 21.4 g/l. In terms of economical wise, corn steep liquor was priced at 200 /ton, which was one fifth of the cost of yeast extract at 1000 /ton. Therefore, corn steep liquor can be considered as a potential nitrogen source in biochemical industries instead of the costly yeast extract.

Carbon, nitrogen, and phosphorus stoichiometry and eutrophication in River Thames Tributaries, UK

USDA-ARS?s Scientific Manuscript database

Primary productivity in aquatic systems relies on the availability of carbon (C), nitrogen (N) and phosphorus (P), with a preferred stoichiometric ratio of 106 C/16 N/1 P, known as the Redfield ratio. The intent of this paper is to present a methodology to visualize C/N/P stoichiometry and examine ...

Prediction of vapour-liquid and vapour-liquid-liquid equilibria of nitrogen-hydrocarbon mixtures used in J-T refrigerators

NASA Astrophysics Data System (ADS)

Narayanan, Vineed; Venkatarathnam, G.

2018-03-01

Nitrogen-hydrocarbon mixtures are widely used as refrigerants in J-T refrigerators operating with mixtures, as well as in natural gas liquefiers. The Peng-Robinson equation of state has traditionally been used to simulate the above cryogenic process. Multi parameter Helmholtz energy equations are now preferred for determining the properties of natural gas. They have, however, been used only to predict vapour-liquid equilibria, and not vapour-liquid-liquid equilibria that can occur in mixtures used in cryogenic mixed refrigerant processes. In this paper the vapour-liquid equilibrium of binary mixtures of nitrogen-methane, nitrogen-ethane, nitrogen-propane, nitrogen-isobutane and three component mixtures of nitrogen-methane-ethane and nitrogen-methane-propane have been studied with the Peng-Robinson and the Helmholtz energy equations of state of NIST REFPROP and compared with experimental data available in the literature.

Combinatorial function of velvet and AreA in transcriptional regulation of nitrate utilization and secondary metabolism.

PubMed

López-Berges, Manuel S; Schäfer, Katja; Hera, Concepción; Di Pietro, Antonio

2014-01-01

Velvet is a conserved protein complex that functions as a regulator of fungal development and secondary metabolism. In the soil-inhabiting pathogen Fusarium oxysporum, velvet governs mycotoxin production and virulence on plant and mammalian hosts. Here we report a previously unrecognized role of the velvet complex in regulation of nitrate metabolism. F. oxysporum mutants lacking VeA or LaeA, two key components of the complex, were impaired in growth on the non-preferred nitrogen sources nitrate and nitrite. Both velvet and the general nitrogen response GATA factor AreA were required for transcriptional activation of nitrate (nit1) and nitrite (nii1) reductase genes under de-repressing conditions, as well as for the nitrate-triggered increase in chromatin accessibility at the nit1 locus. AreA also contributed to chromatin accessibility and expression of two velvet-regulated gene clusters, encoding biosynthesis of the mycotoxin beauvericin and of the siderophore ferricrocin. Thus, velvet and AreA coordinately orchestrate primary and secondary metabolism as well as virulence functions in F. oxysporum. Copyright © 2013 Elsevier Inc. All rights reserved.

Effect of specific amino acids on growth and aflatoxin production by Aspergillus parasiticus and Aspergillus flavus in defined media.

PubMed Central

Payne, G A; Hagler, W M

1983-01-01

Four amino acids were used as sole nitrogen sources or as supplements to ammonium sulfate, and casein and ammonium sulfate were used as sole nitrogen sources to examine their effects on aflatoxin production by Aspergillus parasiticus NRRL 2999 and Aspergillus flavus 3357 grown on synthetic liquid media. In general, when proline, asparagine, casein, and ammonium sulfate were used as sole nitrogen sources, they supported more growth and toxin production than tryptophan or methionine. However, proline stimulated more toxin production per gram of mycelium in stationary cultures than the other nitrogen sources, including the amino acid asparagine, which is generally recognized as supporting good aflatoxin production. The exact responses to individual nitrogen sources were influenced by the species of fungus and whether cultures were stationary or shaken. In shake cultures, but not in stationary cultures, increased growth was generally associated with increased toxin production. PMID:6416168

[Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

PubMed

Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

2015-07-01

Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff.

Effects of the addition of different nitrogen sources in the tequila fermentation process at high sugar concentration.

PubMed

Arrizon, J; Gschaedler, A

2007-04-01

To study the effect of the addition of different nitrogen sources at high sugar concentration in the tequila fermentation process. Fermentations were performed at high sugar concentration (170 g l(-1)) using Agave tequilana Weber blue variety with and without added nitrogen from different sources (ammonium sulfate; glutamic acid; a mixture of ammonium sulfate and amino acids) during the exponential phase of growth. All the additions increased the fermentation rate and alcohol efficiency. The level of synthesis of volatile compounds depended on the source added. The concentration of amyl alcohols and isobutanol were decreased while propanol and acetaldehyde concentration increased. The most efficient nitrogen sources for fermentation rate were ammonium sulfate and the mixture of ammonium sulfate and amino acids. The level of volatile compounds produced depended upon types of nitrogen. The synthesis of some volatile compounds increased while others decreased with nitrogen addition. The addition of nitrogen could be a strategy for improving the fermentation rate and efficiency in the tequila fermentation process at high sugar Agave tequilana concentration. Furthermore, the sensory quality of the final product may change because the synthesis of the volatile compounds is modified.

On the use of response surface methodology to predict and interpret the preferred c-axis orientation of sputtered AlN thin films

NASA Astrophysics Data System (ADS)

Adamczyk, J.; Horny, N.; Tricoteaux, A.; Jouan, P.-Y.; Zadam, M.

2008-01-01

This paper deals with experimental design applied to response surface methodology (RSM) in order to determine the influence of the discharge conditions on preferred c-axis orientation of sputtered AlN thin films. The thin films have been deposited by DC reactive magnetron sputtering on Si (1 0 0) substrates. The preferred orientation was evaluated using a conventional Bragg-Brentano X-ray diffractometer ( θ-2 θ) with the CuKα radiation. We have first determined the experimental domain for 3 parameters: sputtering pressure (2-6 mTorr), discharge current (312-438 mA) and nitrogen percentage (17-33%). For the setup of the experimental design we have used a three factors Doehlert matrix which allows the use of the statistical response surface methodology (RSM) in a spherical domain. A four dimensional surface response, which represents the (0 0 0 2) peak height as a function of sputtering pressure, discharge current and nitrogen percentage, was obtained. It has been found that the main interaction affecting the preferential c-axis orientation was the pressure-nitrogen percentage interaction. It has been proved that a Box-Cox transformation is a very useful method to interpret and discuss the experimental results and leads to predictions in good agreement with experiments.

Evaluation of constructed wetlands by wastewater purification ability and greenhouse gas emissions.

PubMed

Gui, P; Inamori, R; Matsumura, M; Inamori, Y

2007-01-01

Domestic wastewater is a significant source of nitrogen and phosphorus, which cause lake eutrophication. Among the wastewater treatment technologies, constructed wetlands are a promising low-cost means of treating point and diffuse sources of domestic wastewater in rural areas. However, the sustainable operation of constructed wetland treatment systems depends upon a high rate conversion of organic and nitrogenous loading into their metabolic gaseous end products, such as N2O and CH4. In this study, we examined and compared the performance of three typical types of constructed wetlands: Free Water Surface (FWS), Subsurface Flow (SF) and Vertical Flow (VF) wetlands. Pollutant removal efficiency and N2O and CH4 emissions were assessed as measures of performance. We found that the pollutant removal rates and gas emissions measured in the wetlands exhibited clear seasonal changes, and these changes were closely associated with plant growth. VF wetlands exhibited stable removal of organic pollutants and NH3-N throughout the experiment regardless of season and showed great potential for CH4 adsorption. SF wetlands showed preferable T-N removal performance and a lower risk of greenhouse gas emissions than FWS wetlands. Soil oxidation reduction potential (ORP) analysis revealed that water flow structure and plant growth influenced constructed wetland oxygen transfer, and these variations resulted in seasonal changes of ORP distribution inside wetlands that were accompanied by fluctuations in pollutant removal and greenhouse gas emissions.

Nutrient Dynamics of Estuarine Invertebrates Are Shaped by Feeding Guild Rather than Seasonal River Flow

PubMed Central

Ortega-Cisneros, Kelly; Scharler, Ursula M.

2015-01-01

This study aimed to determine the variability of carbon and nitrogen elemental content, stoichiometry and diet proportions of invertebrates in two sub-tropical estuaries in South Africa experiencing seasonal changes in rainfall and river inflow. The elemental ratios and stable isotopes of abiotic sources, zooplankton and macrozoobenthos taxa were analyzed over a dry/wet seasonal cycle. Nutrient content (C, N) and stoichiometry of suspended particulate matter exhibited significant spatio-temporal variations in both estuaries, which were explained by the variability in river inflow. Sediment particulate matter (%C, %N and C:N) was also influenced by the variability in river flow but to a lesser extent. The nutrient content and ratios of the analyzed invertebrates did not significantly vary among seasons with the exception of the copepod Pseudodiaptomus spp. (C:N) and the tanaid Apseudes digitalis (%N, C:N). These changes did not track the seasonal variations of the suspended or sediment particulate matter. Our results suggest that invertebrates managed to maintain their stoichiometry independent of the seasonality in river flow. A significant variability in nitrogen content among estuarine invertebrates was recorded, with highest % N recorded from predators and lowest %N from detritivores. Due to the otherwise general lack of seasonal differences in elemental content and stoichiometry, feeding guild was a major factor shaping the nutrient dynamics of the estuarine invertebrates. The nutrient richer suspended particulate matter was the preferred food source over sediment particulate matter for most invertebrate consumers in many, but not all seasons. The most distinct preference for suspended POM as a food source was apparent from the temporarily open/closed system after the estuary had breached, highlighting the importance of river flow as a driver of invertebrate nutrient dynamics under extreme events conditions. Moreover, our data showed that estuarine invertebrates concentrated C and N between 10–100 fold from trophic level I (POM) to trophic level II (detritivores/deposit feeders) and thus highlighted their importance not only as links to higher trophic level organisms in the food web, but also as providers of a stoichiometrically homeostatic food source for such consumers. As climate change scenarios for the east coast of South Africa predict increased rainfall as a higher number of rainy days and days with higher rainfall, our results suggest that future changes in rainfall and river inflow will have measurable effects on the nutrient content and stoichiometry of food sources and possibly also in estuarine consumers. PMID:26352433

Nutrient Dynamics of Estuarine Invertebrates Are Shaped by Feeding Guild Rather than Seasonal River Flow.

PubMed

Ortega-Cisneros, Kelly; Scharler, Ursula M

2015-01-01

This study aimed to determine the variability of carbon and nitrogen elemental content, stoichiometry and diet proportions of invertebrates in two sub-tropical estuaries in South Africa experiencing seasonal changes in rainfall and river inflow. The elemental ratios and stable isotopes of abiotic sources, zooplankton and macrozoobenthos taxa were analyzed over a dry/wet seasonal cycle. Nutrient content (C, N) and stoichiometry of suspended particulate matter exhibited significant spatio-temporal variations in both estuaries, which were explained by the variability in river inflow. Sediment particulate matter (%C, %N and C:N) was also influenced by the variability in river flow but to a lesser extent. The nutrient content and ratios of the analyzed invertebrates did not significantly vary among seasons with the exception of the copepod Pseudodiaptomus spp. (C:N) and the tanaid Apseudes digitalis (%N, C:N). These changes did not track the seasonal variations of the suspended or sediment particulate matter. Our results suggest that invertebrates managed to maintain their stoichiometry independent of the seasonality in river flow. A significant variability in nitrogen content among estuarine invertebrates was recorded, with highest % N recorded from predators and lowest %N from detritivores. Due to the otherwise general lack of seasonal differences in elemental content and stoichiometry, feeding guild was a major factor shaping the nutrient dynamics of the estuarine invertebrates. The nutrient richer suspended particulate matter was the preferred food source over sediment particulate matter for most invertebrate consumers in many, but not all seasons. The most distinct preference for suspended POM as a food source was apparent from the temporarily open/closed system after the estuary had breached, highlighting the importance of river flow as a driver of invertebrate nutrient dynamics under extreme events conditions. Moreover, our data showed that estuarine invertebrates concentrated C and N between 10-100 fold from trophic level I (POM) to trophic level II (detritivores/deposit feeders) and thus highlighted their importance not only as links to higher trophic level organisms in the food web, but also as providers of a stoichiometrically homeostatic food source for such consumers. As climate change scenarios for the east coast of South Africa predict increased rainfall as a higher number of rainy days and days with higher rainfall, our results suggest that future changes in rainfall and river inflow will have measurable effects on the nutrient content and stoichiometry of food sources and possibly also in estuarine consumers.

Pullulan production by Aureobasidium pullulans grown on ethanol stillage as a nitrogen source.

PubMed

West, T P; Strohfus, B

1996-01-01

Pullulan production by Aureobasidium pullulans strain RP-1 using thin stillage from fuel ethanol production as a nitrogen source was studied in a medium using corn syrup as a carbon source. The use of 1% thin stillage as a nitrogen source instead of ammonium sulphate elevated polysaccharide production by strain RP-1 cells when grown on a concentration of up to 7.5% corn syrup, independent of yeast extract supplementation. Dry weights of cells grown in medium containing ammonium sulphate as the nitrogen source were higher than the stillage-grown cells after 7 days of growth. The viscosity of the polysaccharide on day 7 was higher for cells grown on thin stillage rather than ammonium sulphate as a nitrogen source. The pullulan content of the polysaccharide elaborated by ammonium sulphate-grown cells on day 7 was higher than the pullulan content of polysaccharide produced by stillage-grown cells regardless of whether yeast extract was added to the culture medium.

[Research advances on regulating soil nitrogen loss by the type of nitrogen fertilizer and its application strategy.

PubMed

Zhou, Wei; Lyu, Teng Fei; Yang, Zhi Ping; Sun, Hong; Yang, Liang Jie; Chen, Yong; Ren, Wan Jun

2016-09-01

Unreasonable application of nitrogen fertilizer to cropland decreases nitrogen use efficiency of crop. A large amount of nitrogen loss to environment through runoff, leaching, ammonia volati-lization, nitrification-denitrification, etc., causes water and atmospheric pollution, poses serious environmental problems and threatens human health. The type of nitrogen fertilizer and its application rate, time, and method have significant effects on nitrogen loss. The primary reason for nitrogen loss is attributed to the supersaturated soil nitrogen concentration. Making full use of environmental nitrogen sources, reducing the application rate of chemical nitrogen fertilizers, applying deep placement fertilizing method, and applying organic fertilizers with chemical nitrogen fertilizers, are effective practices for reducing nitrogen loss and improving nitrogen use efficiency. It is suggested that deve-loping new high efficiency nitrogen fertilizers, enhancing nitrogen management, and strengthening the monitoring and use of environmental nitrogen sources are the powerful tools to decrease nitrogen application rate and increase efficiency of cropland.

Role of L-lysine-alpha-ketoglutarate aminotransferase in catabolism of lysine as a nitrogen source for Rhodotorula glutinis.

PubMed Central

Kinzel, J J; Winston, M K; Bhattacharjee, J K

1983-01-01

Wild-type and saccharopine dehydrogenaseless mutant strains of Rhodotorula glutinis grew in minimal medium containing lysine as the sole nitrogen source and simultaneously accumulated, in the culture supernatant, large amounts of a product identified as alpha-aminoadipic-delta-semialdehyde. The saccharopine dehydrogenase and pipecolic acid oxidase levels remained unchanged in wild-type cells grown in the presence of ammonium or lysine as the nitrogen source. Lysine-alpha-ketoglutarate aminotransferase activity was demonstrated in ammonium-grown cells. This activity was depressed in cells grown in the presence of lysine as the sole source of nitrogen. PMID:6408065

Assessment of an apparent relationship between availability of soluble carbohydrates and reduced nitrogen during floral initiation in tobacco

NASA Technical Reports Server (NTRS)

Raper, C. D. Jr; Thomas, J. F.; Tolley-Henry, L.; Rideout, J. W.; Raper CD, J. r. (Principal Investigator)

1988-01-01

Daily relative accumulation rate of soluble carbohydrates (RARS) and reduced nitrogen (RARN) in the shoot, as estimates of source strength, were compared with daily relative growth rates (RGR) of the shoot, as an estimate of sink demand, during floral transformation in apical meristems of tobacco (Nicotiana tabacum 'NC 2326') grown at day/night temperatures of 18/14, 22/18, 26/22, 30/26, and 34/30 C. Source strength was assumed to exceed sink demand for either carbohydrates or nitrogen when the ratio of RARS/RGR or RARN/RGR was greater than unity, and sink demand was assumed to exceed source strength when the ratio was less than unity. Time of floral initiation, which was delayed up to 21 days with increases in temperature over the experimental range, was associated with intervals in which source strength of either carbohydrate or nitrogen exceeded sink demand, while sink demand for the other exceeded source strength. Floral initiation was not observed during intervals in which source strengths of both carbohydrates and nitrogen were greater than or less than sink demand. These results indicate that floral initiation is responsive to an imbalance in the relative availabilities of carbohydrate and nitrogen.

Growth of nitrogen-doped graphene on copper: Multiscale simulations

NASA Astrophysics Data System (ADS)

Gaillard, P.; Schoenhalz, A. L.; Moskovkin, P.; Lucas, S.; Henrard, L.

2016-02-01

We used multiscale simulations to model the growth of nitrogen-doped graphene on a copper substrate by chemical vapour deposition (CVD). Our simulations are based on ab-initio calculations of energy barriers for surface diffusion, which are complemented by larger scale Kinetic Monte Carlo (KMC) simulations. Our results indicate that the shape of grown doped graphene flakes depends on the temperature and deposition flux they are submitted during the process, but we found no significant effect of nitrogen doping on this shape. However, we show that nitrogen atoms have a preference for pyridine-like sites compared to graphite-like sites, as observed experimentally.

Identifying sources of nitrogen to Hanalei Bay, Kauai, utilizing the nitrogen isotope signature of macroalgae

USGS Publications Warehouse

Derse, E.; Knee, K.L.; Wankel, Scott D.; Kendall, C.; Berg, C.J.; Paytan, A.

2007-01-01

Sewage effluent, storm runoff, discharge from polluted rivers, and inputs of groundwater have all been suggested as potential sources of land derived nutrients into Hanalei Bay, Kauai. We determined the nitrogen isotopic signatures (??15N) of different nitrate sources to Hanalei Bay along with the isotopic signature recorded by 11 species of macroalgal collected in the Bay. The macroalgae integrate the isotopic signatures of the nitrate sources over time, thus these data along with the nitrate to dissolved inorganic phosphate molar ratios (N:P) of the macroalgae were used to determine the major nitrate source to the bay ecosystem and which of the macro-nutrients is limiting algae growth, respectively. Relatively low ??15N values (average -0.5???) were observed in all algae collected throughout the Bay; implicating fertilizer, rather than domestic sewage, as an important external source of nitrogen to the coastal water around Hanalei. The N:P ratio in the algae compared to the ratio in the Bay waters imply that the Hanalei Bay coastal ecosystem is nitrogen limited and thus, increased nitrogen input may potentially impactthis coastal ecosystem and specifically the coral reefs in the Bay. Identifying the major source of nutrient loading to the Bay is important for risk assessment and potential remediation plans. ?? 2007 American Chemical Society.

[Food value of the spiruline algae to man].

PubMed

Sautier, C; Tremolieres, J

1975-01-01

The acceptability of various culinary products based on the algae spirulina was tested by questionaire: formulas rich in proteins, soups, omelets, desserts. Spirulina are little appreciated in France due to offensive color, smell and taste. Tomato and chocolate are the most acceptable flavors. Lyophilisation is preferable to atomisation, and discoloration using alcohol is preferable to the acetone method. The hydrolysate obtained, having neither the smell nor the taste of algae, is excellent. Nitrogen, sodium and potassium balances were recorded in 5 undernourished subjects fed via a gastric tube. The spirulina provided respectively 15 p. 100 (1 subject), 30 p. 100 (2 subjects), and 50 p. 100 (2 subjects) of the protein ration. There were no intestinal problems. The spirulina did not modify the investigated balances. However, faecal nitrogen increased to 2.08 g (compared to control period values, 1.33 g and 1.51 g). The various coefficients: digestibility, nitrogen retention and protein utilization did not vary. In man as in animals, nitrogen retention is satisfactory, but digestibility is diminished. Uric acid did not vary in the urine, but serum values increased slightly. Ingestion of spirulina in small doses even over a long period should be tolerable in the normal subject.

Utilization of organic nitrogen by arbuscular mycorrhizal fungi-is there a specific role for protists and ammonia oxidizers?

PubMed

Bukovská, Petra; Bonkowski, Michael; Konvalinková, Tereza; Beskid, Olena; Hujslová, Martina; Püschel, David; Řezáčová, Veronika; Gutiérrez-Núñez, María Semiramis; Gryndler, Milan; Jansa, Jan

2018-04-01

Arbuscular mycorrhizal (AM) fungi can significantly contribute to plant nitrogen (N) uptake from complex organic sources, most likely in concert with activity of soil saprotrophs and other microbes releasing and transforming the N bound in organic forms. Here, we tested whether AM fungus (Rhizophagus irregularis) extraradical hyphal networks showed any preferences towards certain forms of organic N (chitin of fungal or crustacean origin, DNA, clover biomass, or albumin) administered in spatially discrete patches, and how the presence of AM fungal hyphae affected other microbes. By direct 15 N labeling, we also quantified the flux of N to the plants (Andropogon gerardii) through the AM fungal hyphae from fungal chitin and from clover biomass. The AM fungal hyphae colonized patches supplemented with organic N sources significantly more than those receiving only mineral nutrients, organic carbon in form of cellulose, or nothing. Mycorrhizal plants grew 6.4-fold larger and accumulated, on average, 20.3-fold more 15 N originating from the labeled organic sources than their nonmycorrhizal counterparts. Whereas the abundance of microbes (bacteria, fungi, or Acanthamoeba sp.) in the different patches was primarily driven by patch quality, we noted a consistent suppression of the microbial abundances by the presence of AM fungal hyphae. This suppression was particularly strong for ammonia oxidizing bacteria. Our results indicate that AM fungi successfully competed with the other microbes for free ammonium ions and suggest an important role for the notoriously understudied soil protists to play in recycling organic N from soil to plants via AM fungal hyphae.

Ectomycorrhizal Fungal Protein Degradation Ability Predicted by Soil Organic Nitrogen Availability.

PubMed

Rineau, Francois; Stas, Jelle; Nguyen, Nhu H; Kuyper, Thomas W; Carleer, Robert; Vangronsveld, Jaco; Colpaert, Jan V; Kennedy, Peter G

2015-12-18

In temperate and boreal forest ecosystems, nitrogen (N) limitation of tree metabolism is alleviated by ectomycorrhizal (ECM) fungi. As forest soils age, the primary source of N in soil switches from inorganic (NH4 (+) and NO3 (-)) to organic (mostly proteins). It has been hypothesized that ECM fungi adapt to the most common N source in their environment, which implies that fungi growing in older forests would have greater protein degradation abilities. Moreover, recent results for a model ECM fungal species suggest that organic N uptake requires a glucose supply. To test the generality of these hypotheses, we screened 55 strains of 13 Suillus species with different ecological preferences for their in vitro protein degradation abilities. Suillus species preferentially occurring in mature forests, where soil contains more organic matter, had significantly higher protease activity than those from young forests with low-organic-matter soils or species indifferent to forest age. Within species, the protease activities of ecotypes from soils with high or low soil organic N content did not differ significantly, suggesting resource partitioning between mineral and organic soil layers. The secreted protease mixtures were strongly dominated by aspartic peptidases. Glucose addition had variable effects on secreted protease activity; in some species, it triggered activity, but in others, activity was repressed at high concentrations. Collectively, our results indicate that protease activity, a key ectomycorrhizal functional trait, is positively related to environmental N source availability but is also influenced by additional factors, such as carbon availability. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Monitoring plant tissue nitrogen isotopes to assess nearshore inputs of nitrogen to Lake Crescent, Olympic National Park, Washington

USGS Publications Warehouse

Cox, Stephen E.; Moran, Patrick W.; Huffman, Raegan L.; Fradkin, Steven C.

2016-05-31

Mats of filamentous-periphytic algae present in some nearshore areas of Lake Crescent, Olympic National Park, Washington, may indicate early stages of eutrophication from nutrient enrichment of an otherwise highly oligotrophic lake. Natural abundance ratios of stable isotopes of nitrogen (δ15N) measured in plant tissue growing in nearshore areas of the lake indicate that the major source of nitrogen used by these primary producing plants is derived mainly from atmospherically fixed nitrogen in an undeveloped forested ecosystem. Exceptions to this pattern occurred in the Barnes Point area where elevated δ15N ratios indicate that effluent from septic systems also contribute nitrogen to filamentous-periphytic algae growing in the littoral zone of that area. Near the Lyre River outlet of Lake Crescent, the δ15N of filamentous-periphytic algae growing in close proximity to the spawning areas of a unique species of trout show little evidence of elevated δ15N indicating that nitrogen from on-site septic systems is not a substantial source of nitrogen for these plants. The δ15N data corroborate estimates that nitrogen input to Lake Crescent from septic sources is comparatively small relative to input from motor vehicle exhaust and vegetative sources in undeveloped forests, including litterfall, pollen, and symbiotic nitrogen fixation. The seasonal timing of blooms of filamentous-periphytic algal near the lake shoreline is also consistent with nitrogen exported from stands of red alder trees (Alnus rubra). Isotope biomonitoring of filamentous-periphytic algae may be an effective approach to monitoring the littoral zone for nutrient input to Lake Crescent from septic sources.

Effect of ammonium and amino acids on the growth of selected strains of Gluconobacter and Acetobacter.

PubMed

Sainz, F; Mas, A; Torija, M J

2017-02-02

Acetic acid bacteria (AAB) are a group of microorganisms highly used in the food industry. However, its use can be limited by the insufficient information known about the nutritional requirements of AAB for optimal growth. The aim of this work was to study the effects of different concentrations and sources of nitrogen on the growth of selected AAB strains and to establish which nitrogen source best encouraged their growth. Two strains of three species of AAB, Gluconobacter japonicus, Gluconobacter oxydans and Acetobacter malorum, were grown in three different media with diverse nitrogen concentrations (25, 50, 100, and 300mgN/L and 1gN/L) as a complete solution of amino acids and ammonium. With this experiment, the most favourable medium and the lowest nitrogen concentration beneficial for the growth of each strain was selected. Subsequently, under these conditions, single amino acids or ammonium were added to media individually to determine the best nitrogen sources for each AAB strain. The results showed that nitrogen requirements are highly dependent on the nitrogen source, the medium and the AAB strain. Gluconobacter strains were able to grow in the lowest nitrogen concentration tested (25mgN/L); however, one of the G. oxydans strains and both A. malorum strains required a higher concentration of nitrogen (100-300mgN/L) for optimal growth. In general, single nitrogen sources were not able to support the growth of these AAB strains as well as the complete solution of amino acids and ammonium. Copyright © 2016 Elsevier B.V. All rights reserved.

Controlling composition and color characteristics of Monascus pigments by pH and nitrogen sources in submerged fermentation.

PubMed

Shi, Kan; Song, Da; Chen, Gong; Pistolozzi, Marco; Wu, Zhenqiang; Quan, Lei

2015-08-01

Submerged fermentations of Monascus anka were performed with different nitrogen sources at different pH in 3 L bioreactors. The results revealed that the Monascus pigments dominated by different color components (yellow pigments, orange pigments or red pigments) could be selectively produced through pH control and nitrogen source selection. A large amount of intracellular pigments dominated by orange pigments and a small amount of water-soluble extracellular yellow pigments were produced at low pH (pH 2.5 and 4.0), independently of the nitrogen source employed. At higher pH (pH 6.5), the role of the nitrogen source became more significant. In particular, when ammonium sulfate was used as nitrogen source, the intracellular pigments were dominated by red pigments with a small amount of yellow pigments. Conversely, when peptone was used, intracellular pigments were dominated by yellow pigments with a few red pigments derivatives. Neither the presence of peptone nor ammonium sulfate promoted the production of intracellular orange pigments while extracellular pigments with an orangish red color were observed in both cases, with a higher yield when peptone was used. Two-stage pH control fermentation was then performed to improve desirable pigments yield and further investigate the effect of pH and nitrogen sources on pigments composition. These results provide a useful strategy to produce Monascus pigments with different composition and different color characteristics. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Stable Isotopes of Nitrogen in Fossil Cladoceran Exoskeletons: Implications for Nitrogen Sources in the Central Baltic Sea During the Past Century

NASA Astrophysics Data System (ADS)

Struck, Ulrich; Voss, Maren; von Bodungen, Bodo; Mumm, Nicolai

The ratios of stable nitrogen isotopes were analysed in zooplankton exoskeletons extracted from dated sediment cores from the Gotland Basin of the central Baltic Sea. Combined with results on δ15N of bulk sediment, organic carbon concentrations, and abundances of exoskeletons of Bosminalongispinamaritima in the sediment, the data are used to evaluate significant sources of nitrogen in the food web over the past century. Nitrogen isotopic composition of bulk sediments ranges from 2.5 to 4.5ö, that of exokeletons varies between 0.4 and 6.2ö. The two are positively correlated. A marked increase in the abundance of Bosmina since 1965 (from less than 500 specimen to more than 5000 specimencm3 of sediment) is correlated with a significant increase in sedimentary organic carbon concentrations (from 4% to more than 10%). The isotopic data do not identify increased land-derived nitrate as the dominant nitrogen source fuelling the increase. Instead, we postulate that nitrogen fixation by diazotrophic bacteria has been one of the larger sources of nitrogen in the Baltic Sea, as it is today.

DEVELOPING INDICATORS OF NITROGEN SOURCE IN COASTAL ECOSYSTEMS

EPA Science Inventory

Several studies have linked stable isotope ratios of biota to nitrogen source. In particular, ribbed mussels show promise as sensitive indicators of the origins of nitrogen inputs to coastal ecosystems. Here we expand on previous work which demonstrated that mussel isotope ratios...

Watershed delineation and nitrogen source analysis for Bayou Chico, an urban watershed in northwest Florida

EPA Science Inventory

Nutrient pollution in stormwater runoff from urbanized areas contributes to water quality degradation in streams and receiving waterbodies. Agriculture, population growth, and industrial activities are significant sources of nitrogen inputs for surface waters. Increased nitrogen ...

Cyclic variations in nitrogen uptake rate of soybean plants: ammonium as a nitrogen source

NASA Technical Reports Server (NTRS)

Henry, L. T.; Raper, C. D. Jr

1989-01-01

When NO3- is the sole nitrogen source in flowing solution culture, the net rate of nitrogen uptake by nonnodulated soybean (Glycine max L. Merr. cv Ransom) plants cycles between maxima and minima with a periodicity of oscillation that corresponds with the interval of leaf emergence. Since soybean plants accumulate similar quantities of nitrogen when either NH4+ or NO3- is the sole source in solution culture controlled at pH 6.0, an experiment was conducted to determine if the oscillations in net rate of nitrogen uptake also occur when NH4+ is the nitrogen source. During a 21-day period of vegetative development, net uptake of NH4+ was measured daily by ion chromatography as depletion of NH4+ from a replenished nutrient solution containing 1.0 millimolar NH4+. The net rate of NH4+ uptake oscillated with a periodicity that was similar to the interval of leaf emergence. Instances of negative net rates of uptake indicate that the transition between maxima and minima involved changes in influx and efflux components of net NH4+ uptake.

Evaluation of anthropogenic influences on the Luhuitou fringing reef via spatial and temporal analyses (from isotopic values)

NASA Astrophysics Data System (ADS)

Cao, D.; Cao, W.; Yu, K.; Wu, G.; Yang, J.; Su, X.; Wang, F.

2017-05-01

Coral reefs have suffered remarkable declines worldwide. Nutrient overenrichment is considered to be one of the primary local causes. The Luhuitou fringing reef in southern China is a well-known tourist destination that is subject to enormous coastal renovation. The mean δ13C, δ15N value, and carbon over nitrogen ratio (C/N) of particulate organic matter were -21.56 ± 1.94‰, 7.04 ± 3.81‰, and 5.81 ± 1.86, respectively, suggesting mixed sources of carbon and nitrogen. The IsoError calculations suggested that marine phytoplankton and marine benthic algae dominated the majority of carbon sources, while anthropogenic and terrestrial organic nitrogen dominated the nitrogen sources. A tendency toward greater terrestrial detritus and anthropogenic-derived discharges was found during dry seasons and greater marine-derived organic matter during wet seasons. These results demonstrated the existence of anthropogenic influences and high dissolved inorganic nitrogen concentrations and C/N ratios. Anthropogenic nutrient discharge moderated nitrogen limitation, whereas phosphorus became more important to the reef ecosystem. Despite the marine carbon sources dominated, freshwater and terrestrial-derived organic carbon sources were also very important. Meanwhile, anthropogenic and terrestrial organic nitrogen sources were dominant. Therefore, pollution from more extensive region and anthropogenic activities from riverine sewage discharges adjacent to reefs should be focused to effectively reduce human-derived nutrients on reefs.

Climate Change Impacts of US Reactive Nitrogen Emissions

NASA Astrophysics Data System (ADS)

Pinder, R. W.; Davidson, E. A.; Goodale, C. L.; Greaver, T.; Herrick, J.; Liu, L.

2011-12-01

By fossil fuel combustion and fertilizer application, the US has substantially altered the nitrogen cycle, with serious effects on climate change. The climate effects can be short-lived, by impacting the chemistry of the atmosphere, or long-lived, by altering ecosystem greenhouse gas fluxes. Here, we develop a coherent framework for assessing the climate change impacts of US reactive nitrogen emissions. We use the global temperature potential (GTP) as a common metric, and we calculate the GTP at 20 and 100 years in units of CO2 equivalents. At both time-scales, nitrogen enhancement of CO2 uptake has the largest impact, because in the eastern US, areas of high nitrogen deposition are co-located with forests. In the short-term, the effect due to NOx altering ozone and methane concentrations is also substantial, but are not important on the 100 year time scale. Finally, the GTP of N2O emissions is substantial at both time scales. We have also attributed these impacts to combustion and agricultural sources, and quantified the uncertainty. Reactive nitrogen from combustion sources contribute more to cooling than warming. The impacts of agricultural sources tend to cancel each other out, and the net effect is uncertain. Recent trends show decreasing reactive nitrogen from US combustion sources, while agricultural sources are increasing. Fortunately, there are many mitigation strategies currently available to reduce the climate change impacts of US agricultural sources.

Production of polyhydroxybutyrate by the marine photosynthetic bacterium Rhodovulum sulfidophilum P5

NASA Astrophysics Data System (ADS)

Cai, Jinling; Wei, Ying; Zhao, Yupeng; Pan, Guanghua; Wang, Guangce

2012-07-01

The effects of different NaCl concentrations, nitrogen sources, carbon sources, and carbon to nitrogen molar ratios on biomass accumulation and polyhydroxybutyrate (PHB) production were studied in batch cultures of the marine photosynthetic bacterium Rhodovulum sulfidophilum P5 under aerobic-dark conditions. The results show that the accumulation of PHB in strain P5 is a growth-associated process. Strain P5 had maximum biomass and PHB accumulation at 2%-3% NaCl, suggesting that the bacterium can maintain growth and potentially produce PHB at natural seawater salinity. In the nitrogen source test, the maximum biomass accumulation (8.10±0.09 g/L) and PHB production (1.11±0.13 g/L and 14.62%±2.2 of the cell dry weight) were observed when peptone and ammonium chloride were used as the sole nitrogen source. NH{4/+}-N was better for PHB production than other nitrogen sources. In the carbon source test, the maximum biomass concentration (7.65±0.05 g/L) was obtained with malic acid as the sole carbon source, whereas the maximum yield of PHB (5.03±0.18 g/L and 66.93%±1.69% of the cell dry weight) was obtained with sodium pyruvate as the sole carbon source. In the carbon to nitrogen ratios test, sodium pyruvate and ammonium chloride were selected as the carbon and nitrogen sources, respectively. The best carbon to nitrogen molar ratio for biomass accumulation (8.77±0.58 g/L) and PHB production (6.07±0.25 g/L and 69.25%±2.05% of the cell dry weight) was 25. The results provide valuable data on the production of PHB by R. sulfidophilum P5 and further studies are on-going for best cell growth and PHB yield.

Convergent evidence for widespread rock nitrogen sources in Earth’s surface environment

NASA Astrophysics Data System (ADS)

Houlton, B. Z.; Morford, S. L.; Dahlgren, R. A.

2018-04-01

Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth’s land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet’s nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth’s nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink.

Using SPARROW to Model Total Nitrogen Sources, and Transport in Rivers and Streams of California and Adjacent States, U.S.A

NASA Astrophysics Data System (ADS)

Saleh, D.; Domagalski, J. L.

2012-12-01

Sources and factors affecting the transport of total nitrogen are being evaluated for a study area that covers most of California and some areas in Oregon and Nevada, by using the SPARROW model (SPAtially Referenced Regression On Watershed attributes) developed by the U.S. Geological Survey. Mass loads of total nitrogen calculated for monitoring sites at stream gauging stations are regressed against land-use factors affecting nitrogen transport, including fertilizer use, recharge, atmospheric deposition, stream characteristics, and other factors to understand how total nitrogen is transported under average conditions. SPARROW models have been used successfully in other parts of the country to understand how nutrients are transported, and how management strategies can be formulated, such as with Total Maximum Daily Load (TMDL) assessments. Fertilizer use, atmospheric deposition, and climatic data were obtained for 2002, and loads for that year were calculated for monitored streams and point sources (mostly from wastewater treatment plants). The stream loads were calculated by using the adjusted maximum likelihood estimation method (AMLE). River discharge and nitrogen concentrations were de-trended in these calculations in order eliminate the effect of temporal changes on stream load. Effluent discharge information as well as total nitrogen concentrations from point sources were obtained from USEPA databases and from facility records. The model indicates that atmospheric deposition and fertilizer use account for a large percentage of the total nitrogen load in many of the larger watersheds throughout the study area. Point sources, on the other hand, are generally localized around large cities, are considered insignificant sources, and account for a small percentage of the total nitrogen loads throughout the study area.

Diverse plant-associated pleosporalean fungi from saline areas: Ecological tolerance and nitrogen-status dependent effects on plant growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin, Yuan; Pan, Xueyu; Kubicek, Christian

Similar to mycorrhizal mutualists, the rhizospheric and endophytic fungi are also considered to act as active regulators of host fitness (e.g., nutrition and stress tolerance). Despite considerable work in selected model systems, it is generally poorly understood how plant-associated fungi are structured in habitats with extreme conditions and to what extent they contribute to improved plant performance. Here, we investigate the community composition of root and seed-associated fungi from six halophytes growing in saline areas of China, and found that the pleosporalean taxa (Ascomycota) were most frequently isolated across samples. A total of twenty-seven representative isolates were selected for constructionmore » of the phylogeny based on the multi-locus data (partial 18S rDNA, 28S rDNA, and transcription elongation factor 1-a), which classified them into seven families, one clade potentially representing a novel lineage. Fungal isolates were subjected to growth response assays by imposing temperature, pH, ionic and osmotic conditions. The fungi had a wide pH tolerance, while most isolates showed a variable degree of sensitivity to increasing concentration of either salt or sorbitol. Subsequent plant fungal co-culture assays indicated that most isolates had only neutral or even adverse effects on plant growth in the presence of inorganic nitrogen. Interestingly, when provided with organic nitrogen sources the majority of the isolates enhanced plant growth especially above ground biomass. Most of the fungi preferred organic nitrogen over its inorganic counterpart, suggesting that these fungi can readily mineralize organic nitrogen into inorganic nitrogen. Microscopy revealed that several isolates can successfully colonize roots and form melanized hyphae and/or microsclerotia-like structures within cortical cells suggesting a phylogenetic assignment as dark septate endophytes. Furthermore, this work provides a better understanding of the symbiotic relationship between plants and pleosporalean fungi, and initial evidence for the use of this fungal group in benefiting plant production.« less

Diverse plant-associated pleosporalean fungi from saline areas: Ecological tolerance and nitrogen-status dependent effects on plant growth

DOE PAGES

Qin, Yuan; Pan, Xueyu; Kubicek, Christian; ...

2017-02-06

Similar to mycorrhizal mutualists, the rhizospheric and endophytic fungi are also considered to act as active regulators of host fitness (e.g., nutrition and stress tolerance). Despite considerable work in selected model systems, it is generally poorly understood how plant-associated fungi are structured in habitats with extreme conditions and to what extent they contribute to improved plant performance. Here, we investigate the community composition of root and seed-associated fungi from six halophytes growing in saline areas of China, and found that the pleosporalean taxa (Ascomycota) were most frequently isolated across samples. A total of twenty-seven representative isolates were selected for constructionmore » of the phylogeny based on the multi-locus data (partial 18S rDNA, 28S rDNA, and transcription elongation factor 1-a), which classified them into seven families, one clade potentially representing a novel lineage. Fungal isolates were subjected to growth response assays by imposing temperature, pH, ionic and osmotic conditions. The fungi had a wide pH tolerance, while most isolates showed a variable degree of sensitivity to increasing concentration of either salt or sorbitol. Subsequent plant fungal co-culture assays indicated that most isolates had only neutral or even adverse effects on plant growth in the presence of inorganic nitrogen. Interestingly, when provided with organic nitrogen sources the majority of the isolates enhanced plant growth especially above ground biomass. Most of the fungi preferred organic nitrogen over its inorganic counterpart, suggesting that these fungi can readily mineralize organic nitrogen into inorganic nitrogen. Microscopy revealed that several isolates can successfully colonize roots and form melanized hyphae and/or microsclerotia-like structures within cortical cells suggesting a phylogenetic assignment as dark septate endophytes. Furthermore, this work provides a better understanding of the symbiotic relationship between plants and pleosporalean fungi, and initial evidence for the use of this fungal group in benefiting plant production.« less

Nitrogen isotope and mass balance approach in the Elbe Estuary

NASA Astrophysics Data System (ADS)

Sanders, Tina; Wankel, Scott D.; Dähnke, Kirstin

2017-04-01

The supply of bioavailable nitrogen is crucial to primary production in the world's oceans. Especially in estuaries, which act as a nutrient filter for coastal waters, microbial nitrogen turnover and removal has a particular significance. Nitrification as well as other nitrogen-based processes changes the natural abundance of the stable isotope, which can be used as proxies for sources and sinks as well as for process identification. The eutrophic Elbe estuary in northern Germany is loaded with fertilizer-derived nitrogen, but management efforts have started to reduce this load effectively. However, an internal nitrate source in turn gained in importance and the estuary changed from a sink to a source of dissolved inorganic nitrogen: Nitrification is responsible for significant estuarine nutrient regeneration, especially in the Hamburg Port. In our study, we aimed to quantify sources and sinks of nitrogen based on a mass and stable isotope budget in the Elbe estuary. A model was developed reproduce internal N-cycling and associated isotope changes. For that approach we measured dissolved inorganic nitrogen (DIN), particulate nitrogen and their stable isotopes in a case study in July 2013. We found an almost closed mass balance of nitrogen, with only low lost or gains which we attribute to sediment resuspension. The isotope values of different DIN components and the model approach both support a high fractionation of up to -25‰ during nitrification. However, the nitrogen balance and nitrogen stable isotopes suggest that most important processes are remineralization of organic matter to ammonium and further on the oxidation to nitrate. Denitrification and nitrate assimilation play a subordinate role in the Elbe Estuary.

Nitrogen source affects productivity, desiccation tolerance, and storage stability of Beauveria bassiana blastospores

USDA-ARS?s Scientific Manuscript database

Aims: Nitrogen is a critical element in industrial fermentation media. This study investigated the influence of various nitrogen sources on blastospore production, tolerance to anhydrobiosis stress, and storage stability using two strains of the cosmopolitan insect pathogenic fungus Beauveria bassia...

Nitrogen-fixing and uricolytic bacteria associated with the gut of Dendroctonus rhizophagus and Dendroctonus valens (Curculionidae: Scolytinae).

PubMed

Morales-Jiménez, Jesús; Vera-Ponce de León, Arturo; García-Domínguez, Aidé; Martínez-Romero, Esperanza; Zúñiga, Gerardo; Hernández-Rodríguez, César

2013-07-01

The bark beetles of the genus Dendroctonus feed on phloem that is a nitrogen-limited source. Nitrogen fixation and nitrogen recycling may compensate or alleviate such a limitation, and beetle-associated bacteria capable of such processes were identified. Raoultella terrigena, a diazotrophic bacteria present in the gut of Dendroctonus rhizophagus and D. valens, exhibited high acetylene reduction activity in vitro with different carbon sources, and its nifH and nifD genes were sequenced. Bacteria able to recycle uric acid were Pseudomonas fluorescens DVL3A that used it as carbon and nitrogen source, Serratia proteomaculans 2A CDF and Rahnella aquatilis 6-DR that used uric acid as sole nitrogen source. Also, this is the first report about the uric acid content in whole eggs, larvae, and adults (male and female) samples of the red turpentine beetle (Dendroctonus valens). Our results suggest that the gut bacteria of these bark beetles could contribute to insect N balance.

How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels

PubMed Central

Balotf, Sadegh; Islam, Shahidul; Kavoosi, Gholamreza; Kholdebarin, Bahman; Juhasz, Angela

2018-01-01

Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH4NO3) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in Triticum aestivum plants. PMID:29320529

How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels.

PubMed

Balotf, Sadegh; Islam, Shahidul; Kavoosi, Gholamreza; Kholdebarin, Bahman; Juhasz, Angela; Ma, Wujun

2018-01-01

Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH4NO3) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in Triticum aestivum plants.

Stable Isotope Identification of Nitrogen Sources for United States (U.S.) Pacific Coast Estuaries

NASA Astrophysics Data System (ADS)

Brown, C. A.; Kaldy, J. E.; Fong, P.; Fong, C.; Mochon Collura, T.; Clinton, P.

2016-02-01

Nutrients are the leading cause of water quality impairments in the United States, and as a result tools are needed to identify the sources of nutrients. We used natural abundance stable isotope data to evaluate nitrogen sources to U.S. west coast estuaries. We collected macroalgae and analyzed these samples for natural abundance of stable isotopes (δ15N) and supplemented this with available data from the literature for estuaries from Mexico to Alaska. Stable isotope ratios of green macroalgae were compared to δ15N of dissolved inorganic nitrogen of oceanic and watershed end members. There was a latitudinal gradient in δ15N of macroalgae with southern estuaries being 7 per mil heavier than northern estuaries. Gradients in isotope data were compared to nitrogen sources estimated by the USGS using the SPARROW model. In California estuaries, the elevation of isotope data appeared to be related to anthropogenic nitrogen sources. In Oregon systems, the nitrogen levels of streams flowing into the estuaries are related to forest cover, rather than to developed land classes. In Oregon estuaries, the δ15N of macroalgae suggested that the ocean and nitrogen-fixing trees in the watersheds were the dominant nitrogen sources with heavier sites located near the estuary mouth. In California estuaries, the gradient was reversed with heavier sites located upriver. In some Oregon estuaries, there was an elevation an elevation of δ15N above marine end members in the vicinity of wastewater treatment facility discharge locations, suggesting isotopes may be useful for distinguishing inputs along an estuarine gradient.

Atmospheric nitrogen deposition to China: a model analysis on nitrogen budget and critical load exceedance

NASA Astrophysics Data System (ADS)

Zhao, Y.; Zhang, L.; Chen, Y.; Liu, X.; Xu, W.; Pan, Y.; Duan, L.

2016-12-01

We present a national-scale model analysis of the sources and processes of inorganic nitrogen deposition over China using the GEOS-Chem model at 1/2°×1/3° horizontal resolution. Averaged model results for 2008-2012 are evaluated with an ensemble of surface measurements of nitrogen wet deposition flux and concentration, and satellite measurements of tropospheric NO2 columns. Annual inorganic nitrogen deposition fluxes are shown to be generally less than 10 kg N ha-1 a-1 in the western China, 15-50 kg N ha-1 a-1 in the eastern China, and 15.6 kg N ha-1 a-1 averaged over China. The model simulates an annual total deposition flux of 16.4 Tg N to China, with 10.3 Tg N (63%) from reduced nitrogen (NHx) and 6.2 Tg N from oxidized nitrogen (NOy). Domestic anthropogenic sources contribute 86% of the total deposition; foreign anthropogenic sources 7% and natural sources 7%. Annually 23% of domestically emitted NH3 and 36% for NOx are exported out of China. We also find while nitrogen deposition to China is comparable to the nitrogen input from fertilizer application (16.5 Tg N a-1) on the national scale, it is much more widely distributed spatially. The deposition flux is also much higher than natural biological fixation (7.3 Tg N a-1). A comparison with estimates of nitrogen critical load for eutrophication indicates that about 40% of the land over China faces nitrogen critical load exceedances. However, 45% of the exceeding areas, mainly in Beijing-Tianjin-Hebei, Central China, East China, and South China, will not occur in the absence of nitrogen deposition, demonstrating the necessity of nitrogen emission controls to avoid potential negative ecological effects over these areas.

Nitrogen Loading in Jamaica Bay, Long Island, New York: Predevelopment to 2005

USGS Publications Warehouse

Benotti, Mark J.; Abbene, Irene; Terracciano, Stephen A.

2007-01-01

Nitrogen loading to Jamaica Bay, a highly urbanized estuary on the southern shore of western Long Island, New York, has increased from an estimated rate of 35.6 kilograms per day (kg/d) under predevelopment conditions (pre-1900), chiefly as nitrate plus nitrite from ground-water inflow, to an estimated 15,800 kilograms per day as total nitrogen in 2005. The principal point sources are wastewater-treatment plants, combined sewer overflow/stormwater discharge during heavy precipitation, and subway dewatering, which account for 92 percent of the current (2005) nitrogen load. The principal nonpoint sources are landfill leachate, ground-water flow, and atmospheric deposition, which account for 8 percent of the current nitrogen load. The largest single source of nitrogen to Jamaica Bay is wastewater-treatment plants, which account for 89 percent of the nitrogen load. The current and historic contributions of nitrogen from seawater are unknown, although at present, the ocean likely serves as a sink for nitrogen from Jamaica Bay. Currently, concentrations of nitrogen in surface water are high throughout Jamaica Bay, but some areas with relatively little mixing have concentrations that are five times higher than areas that are well mixed.

Optimization of the freezing process for hematopoietic progenitor cells: effect of precooling, initial dimethyl sulfoxide concentration, freezing program, and storage in vapor-phase or liquid nitrogen on in vitro white blood cell quality.

PubMed

Dijkstra-Tiekstra, Margriet J; Setroikromo, Airies C; Kraan, Marcha; Gkoumassi, Effimia; de Wildt-Eggen, Janny

2014-12-01

Adding dimethyl sulfoxide (DMSO) to hematopoietic progenitor cells (HPCs) causes an exothermic reaction, potentially affecting their viability. The freezing method might also influence this. The aim was to investigate the effect of 1) precooling of DMSO and plasma (D/P) and white blood cell (WBC)-enriched product, 2) DMSO concentration of D/P, 3) freezing program, and 4) storage method on WBC quality. WBC-enriched product without CD34+ cells was used instead of HPCs. This was divided into six or eight portions. D/P (20 or 50%; precooled or room temperature [RT]) was added to the WBC-enriched product (precooled or RT), resulting in 10% DMSO, while monitoring temperature. The product was frozen using controlled-rate freezing ("fast-rate" or "slow-rate") and placed in vapor-phase or liquid nitrogen. After thawing, WBC recovery and viability were determined. Temperature increased most for precooled D/P to precooled WBC-enriched product, without influence of 20 or 50% D/P, but remained for all variations below 30°C. WBC recovery for both freezing programs was more than 95%. Recovery of WBC viability was higher for slow-rate freezing compared to fast-rate freezing (74% vs. 61%; p < 0.05) and also for 50% compared to 20% D/P (two test variations). Effect of precooling D/P or WBC-enriched product and of storage in vapor-phase or liquid nitrogen was marginal. Based on these results, precooling is not necessary. Fifty percent D/P is preferred over 20% D/P. Slow-rate freezing is preferred over fast-rate freezing. For safety reasons storage in vapor-phase nitrogen is preferred over storage in liquid nitrogen. Additional testing using real HPCs might be necessary. © 2014 AABB.

Effects of watershed land use on nitrogen concentrations and δ15 nitrogen in groundwater

USGS Publications Warehouse

Cole, Marci L.; Kroeger, Kevin D.; McClelland, J.W.; Valiela, I.

2006-01-01

Eutrophication is a major agent of change affecting freshwater, estuarine, and marine systems. It is largely driven by transportation of nitrogen from natural and anthropogenic sources. Research is needed to quantify this nitrogen delivery and to link the delivery to specific land-derived sources. In this study we measured nitrogen concentrations and δ 15N values in seepage water entering three freshwater ponds and six estuaries on Cape Cod, Massachusetts and assessed how they varied with different types of land use. Nitrate concentrations and δ 15N values in groundwater reflected land use in developed and pristine watersheds. In particular, watersheds with larger populations delivered larger nitrate loads with higher δ 15N values to receiving waters. The enriched δ 15N values confirmed nitrogen loading model results identifying wastewater contributions from septic tanks as the major N source. Furthermore, it was apparent that N coastal sources had a relatively larger impact on the N loads and isotopic signatures than did inland N sources further upstream in the watersheds. This finding suggests that management priorities could focus on coastal sources as a first course of action. This would require management constraints on a much smaller population.

Dominance of organic nitrogen from headwater streams to large rivers across the conterminous United States

USGS Publications Warehouse

Scott, D.; Harvey, J.; Alexander, R.; Schwarz, G.

2007-01-01

The frequency and magnitude of hypoxic areas in coastal waterbodies are increasing across the globe, partially in response to the increase in nitrogen delivery from the landscape (Diaz, 2001; Rabalais et al., 2002). Although studies of annual total nitrogen and nitrate yields have greatly improved understanding of the contaminant sources that contribute to riverine nitrogen loads (Alexander et al., 2000; Caraco and Cole, 1999), the emphasis of these studies on annual timescales and selected nitrogen forms is not sufficient to understand the factors that control the cycling, transport, and fate of reactive nitrogen. Here we use data from 850 river stations to calculate long-term mean-annual and interannual loads of organic, ammonia, and nitrate-nitrite nitrogen suitable for spatial analysis. We find that organic nitrogen is the dominant nitrogen pool within rivers across most of the United States and is significant even in basins with high anthropogenic sources of nitrogen. Downstream organic nitrogen patterns illustrate that organic nitrogen is an abundant fraction of the nitrogen loads in all regions. Although the longitudinal patterns are not consistent across regions, these patterns are suggestive of cycling between ON and NO3- on seasonal timescales influenced by land use, stream morphology, and riparian connectivity with active floodplains. Future regional studies need to incorporate multinitrogen species at intraannual timescales, as well as stream characteristics beyond channel depth, to elucidate the roles of nitrogen sources and in-stream transformations on the fate and reactivity of riverine nitrogen transported to coastal seas.

Dominance of organic nitrogen from headwater streams to large rivers across the conterminous United States

NASA Astrophysics Data System (ADS)

Scott, Durelle; Harvey, Judson; Alexander, Richard; Schwarz, Gregory

2007-03-01

The frequency and magnitude of hypoxic areas in coastal waterbodies are increasing across the globe, partially in response to the increase in nitrogen delivery from the landscape (Diaz, 2001; Rabalais et al., 2002). Although studies of annual total nitrogen and nitrate yields have greatly improved understanding of the contaminant sources that contribute to riverine nitrogen loads (Alexander et al., 2000; Caraco and Cole, 1999), the emphasis of these studies on annual timescales and selected nitrogen forms is not sufficient to understand the factors that control the cycling, transport, and fate of reactive nitrogen. Here we use data from 850 river stations to calculate long-term mean-annual and interannual loads of organic, ammonia, and nitrate-nitrite nitrogen suitable for spatial analysis. We find that organic nitrogen is the dominant nitrogen pool within rivers across most of the United States and is significant even in basins with high anthropogenic sources of nitrogen. Downstream organic nitrogen patterns illustrate that organic nitrogen is an abundant fraction of the nitrogen loads in all regions. Although the longitudinal patterns are not consistent across regions, these patterns are suggestive of cycling between ON and NO3- on seasonal timescales influenced by land use, stream morphology, and riparian connectivity with active floodplains. Future regional studies need to incorporate multinitrogen species at intraannual timescales, as well as stream characteristics beyond channel depth, to elucidate the roles of nitrogen sources and in-stream transformations on the fate and reactivity of riverine nitrogen transported to coastal seas.

Use of pharmaceuticals and pesticides to constrain nutrient sources in coastal groundwater of northwestern Long Island, New York, USA

USGS Publications Warehouse

Zhao, S.; Zhang, P.; Crusius, John; Kroeger, K.D.; Bratton, J.F.

2011-01-01

In developed, non-agricultural, unsewered areas, septic systems and fertilizer application to lawns and gardens represent two major sources of nitrogen to coastal groundwater, in addition to atmospheric input. This study was designed to distinguish between these two possible nitrogen sources by analyzing groundwater samples for pharmaceutical residuals, because fertilizers do not contain any of these pharmaceuticals, but domestic wastewater commonly does. In addition, several herbicides and insecticides used in lawn treatment were analyzed as indicators of nitrogen delivery to groundwater from fertilizers. Groundwater samples were taken through piezometres at shoreline sites in unsewered areas surrounding Northport Harbor and in sewered areas adjacent to Manhasset Bay (hereafter referred to as "Northport" and "Manhasset", respectively), both in northwestern Long Island, USA. Excessive nitrogen loading has led to reduced dissolved oxygen concentrations in Long Island Sound, and the groundwater contribution to the nitrogen budget is poorly constrained. The frequent detection of the anticonvulsant compound carbamazepine in groundwater samples of the Northport Harbor area (unsewered), together with the fact that few pesticides associated with lawn applications were detected, suggests that wastewater input and atmospheric input are the likely sources of nitrogen in the Northport groundwater. High concentrations of nitrogen were also detected in the Manhasset (sewered) groundwater. The low detection frequency and concentration of carbamazepine, however, suggest that the sewer system effectively intercepts nitrogen from wastewater there. The likely sources of nitrogen in the Manhasset groundwater are atmospheric deposition and lawn fertilizers, as this area is densely populated.

QUANTIFYING SEASONAL SHIFTS IN NITROGEN SOURCES TO OREGON ESTUARIES: PART II: TRANSPORT MODELING

EPA Science Inventory

Identifying the sources of dissolved inorganic nitrogen (DIN) in estuaries is complicated by the multiple sources, temporal variability in inputs, and variations in transport. We used a hydrodynamic model to simulate the transport and uptake of three sources of DIN (oceanic, riv...

Comprehensive trends assessment of nitrogen sources and loads to estuaries of the coterminous United States

EPA Science Inventory

Sources of nitrogen and phosphorus to estuaries and estuarine watersheds of the coterminous United States have been compiled from a variety of publically available data sources (1985 – 2015). Atmospheric loading was obtained from two sources. Modelled and interpolated meas...

An innovative wood-chip-framework substrate used as slow-release carbon source to treat high-strength nitrogen wastewater.

PubMed

Li, Huai; Chi, Zifang; Yan, Baixing; Cheng, Long; Li, Jianzheng

2017-01-01

Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems. However, nitrogen removal efficiency is usually limited due to the low carbon/nitrogen (C/N) ratio. A common solution is to add external carbon sources, but amount of liquid is difficult to determine. Therefore, a combined wood-chip-framework substrate (with wood, slag and gravel) as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem. Results show that the removal rate of ammonia nitrogen (NH 4 + -N), total nitrogen (TN) and chemical oxygen demand (COD) could reach 37.5%-85%, 57.4%-86%, 32.4%-78%, respectively, indicating the combined substrate could diffuse sufficient oxygen for the nitrification process (slag and gravel zone) and provide carbon source for denitrification process (wood-chip zone). The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip, respectively. Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification-denitrification process, while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process. This study provides a new idea for wetland treatment of high-strength nitrogen wastewater. Copyright © 2016. Published by Elsevier B.V.

Atmospheric Ionization by Solar Particles Detected by Nitrate Measurements in Antarctic Snow. FY91 AASERT

NASA Technical Reports Server (NTRS)

Vitt, Francis M.; Jackman, Charles H.

1995-01-01

The odd nitrogen source strengths associated with Solar Proton Events (SPEs), Galactic Cosmic Rays (GCRs), and the oxidation of nitrous oxide in the Earth's middle atmosphere from 1974 through 1993 have been compared globally, at middle and lower latitudes (less than 50 deg), and polar regions (greater than 50 deg) with a two-dimensional (2-D) photochemical transport model. As discovered previously, the oxidation of nitrous oxide dominates the global odd nitrogen source while GCRs and SPEs are significant at polar latitudes. The horizontal transport of odd nitrogen, produced by the oxidation of nitrous oxide at latitudes < 50 deg, was found to be the dominant source of odd nitrogen in the polar regions with GCRs contributing substantially during the entire solar cycle. The source of odd nitrogen from SPEs was more sporadic; however, contributions during several years (mostly near solar maximum) were significant in the polar middle atmosphere.

78 FR 46552 - Approval and Promulgation of Air Quality Implementation Plans; Massachusetts; Regulations...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-01

... Volatile Organic Compounds and Nitrogen Oxides AGENCY: Environmental Protection Agency (EPA). ACTION... requirements for stationary sources of volatile organic compounds (VOCs) and nitrogen oxides (NO X ). This... to 310 CMR 7.19, Reasonably Available Control Technology (RACT) for Sources of Oxides of Nitrogen (NO...

The AreA transcription factor in Fusarium graminearum regulates the use of some nonpreferred nitrogen sources and secondary metabolite production.

PubMed

Giese, Henriette; Sondergaard, Teis Esben; Sørensen, Jens Laurids

2013-01-01

Growth conditions are known to affect the production of secondary metabolites in filamentous fungi. The influence of different nitrogen sources and the transcription factor AreA on the production of mycotoxins in Fusarium graminearum was examined. Growth on glutamine or NH4-sources was poor and asparagine was found to be a preferential nitrogen source for F. graminearum. Deletion of areA led to poor growth on NaNO₃ suggesting its involvement in regulation of the nitrate reduction process. In addition utilization of aspartic acid, histidine, isoleucine, leucine, threonine, tyrosine, and valine as nitrogen sources was shown to depend of a functional AreA. AreA was shown to be required for the production of the mycotoxins deoxynivalenol (DON), zearalenone, and fusarielin H regardless of the nutrient medium. Deletion of nmr, the repressor of AreA under nitrogen sufficient conditions, had little effect on either growth or toxin production. AreA appears to regulate production of some mycotoxins directly or indirectly independent on nitrogen status and plays a role in utilization of certain amino acids. Copyright © 2013 The British Mycological Society. All rights reserved.

Enhanced microalgal lipid production with media engineering of potassium nitrate as a nitrogen source.

PubMed

Gour, Rakesh Singh; Bairagi, Madhusudan; Garlapati, Vijay Kumar; Kant, Anil

2018-01-01

Algal biofuels are far from a commercial reality due to the technical challenges associated with their growth and lipid extraction procedures. In this study, we investigated the effect of 4 different media and 5 different nitrogen sources at 5 levels on the growth, biomass and lipid productivity of Scenedesmus sp and Chlorella sp The hypothesis was that a nitrogen source can be identified that provides enough stress to accumulate lipids without compromising significantly on biomass and lipid productivity. A maximum specific growth rate and doubling per day have been observed with algal species using modified BG-11 medium. Among the tested nitrogen sources, 2.5 mM potassium nitrate as a nitrogen constituent of modified BG-11 medium resulted in higher lipid content and productivity in the case of S. dimorphus (29.15%, 15.449 mg L -1 day -1 ). Another noteworthy outcome of the present study lies in the usage of a smaller amount of the nitrogen source, i.e., 2.5 mM, which is found to be 7 times less than the standard BG11 media (17.60 mM sodium nitrate).

Effect of nitrogen sources on biomass, lipid and docosahexanoic acid production by Aurantiochytrium sp. SW1

NASA Astrophysics Data System (ADS)

Auma, Khairunnisa; Hamid, Aidil Abdul; Yusoff, Wan Mohtar Wan

2018-04-01

A local isolate, Aurantiochytrium sp. SW1 has been verified to have high content of docosahexanoic acid (DHA). However, the effect of different nitrogen sources on biomass, lipid concentration and DHA content in Aurantiochytrium sp. SW1 is still unknown. Hence, this study is focused in using six different organic and inorganic nitrogen sources to grow Aurantiochytrium sp. SW1 in optimized Burja medium. Monosodium glutamate (MSG) gave the highest biomass concentration of 15.97 g/L followed by ammonium nitrate (NH4NO3) with 13.37 g/L at 96 hr. These two nitrogen sources had significant effect on the biomass concentration (p<0.05). The highest lipid accumulated was obtained using MSG that reached 79.6% in biomass concentration. DHA content in lipid showed cultivation using MSG reached 47.9% (4.95 g/L). Statistical analysis using least significant difference (LSD) showed significant lipid production (p<0.05) when cultivated in MSG compared to other five nitrogen sources. The highest DHA productivity (0.052 g/L hr-1) was obtained in medium containing MSG. This study proves that nitrogen component in the medium significantly affects the biomass concentration, lipid and DHA content.

Nitrogen Source-Dependent Capsule Induction in Human-Pathogenic Cryptococcus Species

PubMed Central

Frazzitta, Aubrey E.; Vora, Haily; Price, Michael S.; Tenor, Jennifer L.; Betancourt-Quiroz, Marisol; Toffaletti, Dena L.; Cheng, Nan

2013-01-01

Cryptococcus neoformans and C. gattii cause meningoencephalitis and are an increasing human health threat. These pathogenic Cryptococcus species are neurotropic and persist in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients, such as carbon and nitrogen, from the CSF. To enhance our understanding of nutrient acquisition during central nervous system infection by Cryptococcus species, we examined the utilization of nitrogen sources available in CSF. We screened for the growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Both environmental and clinical strains grew robustly on uric acid, Casamino Acids, creatinine, and asparagine as sole nitrogen sources. Urea induced the greatest magnitude of capsule induction. This induction was greater in Cryptococcus gattii than in C. neoformans. We confirmed the ability of nonpreferred nitrogen sources to increase capsule production in pathogenic species of Cryptococcus. Since urea is metabolized to ammonia and CO2 (a known signal for capsule induction), we examined urea metabolism mutants for their transcriptional response to urea regarding capsule production. The transcriptional profile of C. neoformans under urea-supplemented conditions revealed both similar and unique responses to other capsule-inducing conditions, including both intra- and extracellular urea utilization. As one of the most abundant nitrogen sources in the CSF, the ability of Cryptococcus to import urea and induce capsule production may substantially aid this yeast's survival and propagation in the host. PMID:23975889

Nitrogen source-dependent capsule induction in human-pathogenic cryptococcus species.

PubMed

Frazzitta, Aubrey E; Vora, Haily; Price, Michael S; Tenor, Jennifer L; Betancourt-Quiroz, Marisol; Toffaletti, Dena L; Cheng, Nan; Perfect, John R

2013-11-01

Cryptococcus neoformans and C. gattii cause meningoencephalitis and are an increasing human health threat. These pathogenic Cryptococcus species are neurotropic and persist in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients, such as carbon and nitrogen, from the CSF. To enhance our understanding of nutrient acquisition during central nervous system infection by Cryptococcus species, we examined the utilization of nitrogen sources available in CSF. We screened for the growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Both environmental and clinical strains grew robustly on uric acid, Casamino Acids, creatinine, and asparagine as sole nitrogen sources. Urea induced the greatest magnitude of capsule induction. This induction was greater in Cryptococcus gattii than in C. neoformans. We confirmed the ability of nonpreferred nitrogen sources to increase capsule production in pathogenic species of Cryptococcus. Since urea is metabolized to ammonia and CO(2) (a known signal for capsule induction), we examined urea metabolism mutants for their transcriptional response to urea regarding capsule production. The transcriptional profile of C. neoformans under urea-supplemented conditions revealed both similar and unique responses to other capsule-inducing conditions, including both intra- and extracellular urea utilization. As one of the most abundant nitrogen sources in the CSF, the ability of Cryptococcus to import urea and induce capsule production may substantially aid this yeast's survival and propagation in the host.

Stable nitrogen isotopes in coastal macroalgae: geographic and anthropogenic variability.

PubMed

Viana, Inés G; Bode, Antonio

2013-01-15

Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ(15)N). In this study δ(15)N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ(15)N was not related to either inorganic nitrogen concentrations or δ(15)N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ(15)N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ(15)N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15×10(3) inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ(15)N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Analysis of Nitrogen Loads From Long Island Sound Watersheds, 1988-98

NASA Astrophysics Data System (ADS)

Mullaney, J. R.; Trench, E. C.

2001-05-01

The U.S. Geological Survey (USGS) recently estimated annual nonpoint-source nitrogen loads from watersheds that drain to Long Island Sound. The study, was conducted in cooperation with the Connecticut Department of Environmental Protection, the New York State Department of Environmental Conservation and the U.S. Environmental Protection Agency, to assist these agencies with the issue of low concentrations of dissolved oxygen in Long Island Sound caused by nitrogen enrichment. A regression model was used to determine annual nitrogen loads at 27 streams monitored by the USGS during 1988-98. Estimates of nitrogen loads from municipal wastewater-treatment plants (where applicable) were subtracted from the total nitrogen loads to determine the nonpoint-source nitrogen load for each water-quality monitoring station. The nonpoint-source load information was applied to unmonitored areas by comparing the land-use and land-cover characteristics of monitored areas with unmonitored areas, and selecting basins that were most similar. In extrapolating load estimates to unmonitored areas, regional differences in mean annual runoff between monitored and unmonitored areas also were considered, using flow information from nearby USGS gaging stations. Estimates of nonpoint nitrogen loads from monitored areas with point sources of nitrogen discharge and estimates from unmonitored areas are subject to uncertainty. These estimates could be improved with additional data collection in coastal basins and in basins with a large percentage of urbanized land, measurements of instream transformation or losses of nitrogen, improved reporting of total nitrogen concentrations from municipal wastewater treatment facilities, and tracking of intrabasin and (or) interbasin diversion of water.

Stable Isotope Identification of Nitrogen Sources for United ...

EPA Pesticide Factsheets

We used natural abundance stable isotope data to evaluate nitrogen sources to U.S. west coast estuaries. We collected δ15N of macroalgae data and supplemented this with available data from the literature for estuaries from Mexico to Alaska. Stable isotope ratios of green macroalgae were compared to δ15N of dissolved inorganic nitrogen of oceanic and watershed end members. There was a latitudinal gradient in δ15N of macroalgae with southern estuaries being 7 per mil heavier than northern estuaries. Gradients in isotope data were compared to nitrogen sources estimated by the USGS using the SPARROW model. In California estuaries, the elevation of isotope data appeared to be related to anthropogenic nitrogen sources. In Oregon systems, the nitrogen levels of streams flowing into the estuaries are related to forest cover, rather than to developed land classes. In addition, the δ15N of macroalgae suggested that the ocean and nitrogen-fixing trees in the watersheds were the dominant nitrogen sources. There was also a strong gradient in δ15N of macroalgae with heavier sites located near the estuary mouth. In some Oregon estuaries, there was an elevation an elevation of δ15N above marine end members in the vicinity of wastewater treatment facility discharge locations, suggesting isotopes may be useful for distinguishing inputs along an estuarine gradient. Nutrients are the leading cause of water quality impairments in the United States, and as a result too

Quantifying seasonal shifts in nitrogen sources to Oregon estuaries using a transport model combined with stable isotopes

EPA Science Inventory

Identifying the sources of dissolved inorganic nitrogen (DIN) in estuaries is complicated by the multiple sources, temporal variability in inputs, and variations in transport. We used a hydrodynamic model to simulate the transport and uptake of three sources of DIN (oceanic, riv...

Chapter 7: Impact of Nitrogen and Climate Change Interactions on Ambient Air Pollution and Human Health

EPA Science Inventory

Nitrogen oxides (NOX) are important components of ambient and indoor air pollution and are emitted from a range of combustion sources, including on-road mobile sources, electric power generators, and non-road mobile sources. While anthropogenic sources dominate, NOX is also forme...

The estimation of the load of non-point source nitrogen and phosphorus based on observation experiments and export coefficient method in Three Gorges Reservoir Area

NASA Astrophysics Data System (ADS)

Tong, X. X.; Hu, B.; Xu, W. S.; Liu, J. G.; Zhang, P. C.

2017-12-01

In this paper, Three Gorges Reservoir Area (TGRA) was chosen to be the study area, the export coefficients of different land-use type were calculated through the observation experiments and literature consultation, and then the load of non-point source (NPS) nitrogen and phosphorus of different pollution sources such as farmland pollution sources, decentralized livestock and poultry breeding pollution sources and domestic pollution sources were estimated. The results show as follows: the pollution load of dry land is the main source of farmland pollution. The order of total nitrogen load of different pollution sources from high to low is livestock breeding pollution, domestic pollution, land use pollution, while the order of phosphorus load of different pollution sources from high to low is land use pollution, livestock breeding pollution, domestic pollution, Therefore, reasonable farmland management, effective control methods of dry land fertilization and sewage discharge of livestock breeding are the keys to the prevention and control of NPS nitrogen and phosphorus in TGRA.

Use of Nitrogen-15 Isotope Method in Soils and Ground Water to Determine Potential Nitrogen Sources Affecting a Municipal Water Supply in Kansas, USA

NASA Astrophysics Data System (ADS)

Townsend, M. A.; Macko, S. A.

2004-12-01

Nitrate-N concentrations have increased to greater than 10 mg/L in a municipal water supply in western Kansas from 1995 to 2002. A study was done by the Kansas Geological Survey using the nitrogen-15 natural abundance isotope method to determine potential sources for the increasing nitrate concentrations. Preliminary results of the isotope analyses on water samples suggest that animal waste and/or denitrification enrichment has affected the water supply. Soil samples from areas near the wells that were not treated with manure show a general increase of nitrogen-15 signature (+9 to +15 \\permil) to a depth of 5 m. Soils are silt loams with measurable carbonate (0.8 to 2 % by weight) in the profile, which may permit volatilization enrichment to occur in the soil profile. Wells in the area range from 11 to 20 m in alluvial deposits with depth to water at approximately 9 m). Nitrate-N values range from 8 to 26 mg/L. Nitrogen-15 values range from (+17 to +28 \\permil) with no obvious source of animal waste near the well sites. There are potential nearby long-term sources of animal waste - an abandoned sewage treatment plant and an agricultural testing farm. One well has a reducing chemistry with a nitrate value of 0.9 mg/L and a nitrogen-15 value of +17 \\permil suggesting that alluvial sediment variation also has an impact on the water quality in the study area. The other wells show values of nitrate and nitrogen-15 that are much greater than the associated soils. The use of nitrogen-15 alone permited limited evaluation of sources of nitrate to ground water particularly in areas with carbonate in the soils. Use of oxygen-18 on nitrate will permit the delineation of the processes affecting the nitrogen in the soil profile and determination of the probable sources and the processes that have affected the nitrogen in the ground water. Final results of the nitrogen-15 and oxygen-18 analyses will be presented.

The influence of various carbon and nitrogen sources on oil production by Fusarium oxysporum.

PubMed

Joshi, S; Mathur, J M

1987-01-01

The oil-synthesizing capacity of Fusarium oxysporum, cultivated on basal nutrient medium, was evaluated using different carbon and nitrogen sources. In one of the media, molasses was also used as a principal carbon source. Media containing glucose and ammonium nitrate were found to be most efficient for oil production. Fatty acid profile of the fungal oil indicated the presence of a wide range of fatty acids ranging from C8 to C24. Fatty acid composition largely depends on the type of carbon and nitrogen sources.

Use of stable isotopes of nitrogen and water to identify sources of nitrogen in three urban creeks of Durham, North Carolina, 2011-12

USGS Publications Warehouse

McSwain, Kristen Bukowski; Young, Megan B.; Giorgino, Mary L.

2014-01-01

A preliminary assessment of nitrate sources was conducted in three creeks that feed nutrient impaired Falls and Jordan Lakes in the vicinity of Durham County, North Carolina, from July 2011 to June 2012. Cabin Branch, Ellerbe Creek, and Third Fork Creek were sampled monthly to determine if sources of nitrate in surface water could be identified on the basis of their stable isotopic compositions. Land use differs in the drainage basins of the investigated creeks—the predominant land use in Cabin Branch Basin is forest, and the Ellerbe and Third Fork Creek Basins are predominantly developed urban areas. Total nutrient concentrations were below 1 milligram per liter (mg/L). All measured nitrate plus nitrite concentrations were below the North Carolina standard of 10 mg/L as nitrogen with the highest concentration of 0.363 mg/L measured in Third Fork Creek. Concentrations of ammonia were generally less than 0.1 mg/L as nitrogen in all creek samples. More than 50 percent of the total nitrogen measured in the creeks was in the form of organic nitrogen. Total phosphorus and orthophosphate concentrations in all samples were generally less than 0.2 mg/L as phosphorus. The isotopic composition of surface water (δ2HH20 and δ18OH2O) is similar to that of modern-day precipitation. During July and August 2011 and May and June 2012, surface-water samples displayed a seasonal difference in isotopic composition, indicating fractionation of isotopes as a result of evaporation and, potentially, mixing with local and regional groundwater. The dominant source of nitrate to Cabin Branch, Ellerbe Creek, and Third Fork Creek was the nitrification of soil nitrogen. Two stormflow samples in Ellerbe Creek and Third Fork Creek had nitrate sources that were a mixture of the nitrification of soil nitrogen and an atmospheric source that had bypassed some soil contact through impermeable surfaces within the drainage basin. No influence of a septic or wastewater source was found in Cabin Branch. Results from this study suggest that it is possible to distinguish sources of nitrogen and biogeochemical processes on nitrate using stable isotopes of nitrogen and oxygen in small creeks of Durham County, North Carolina.

Molecular signature of organic nitrogen in septic-impacted groundwater

USGS Publications Warehouse

Arnold, William A.; Longnecker, Krista; Kroeger, Kevin D.; Kujawinski, Elizabeth B.

2014-01-01

Dissolved inorganic and organic nitrogen levels are elevated in aquatic systems due to anthropogenic activities. Dissolved organic nitrogen (DON) arises from various sources, and its impact could be more clearly constrained if specific sources were identified and if the molecular-level composition of DON were better understood. In this work, the pharmaceutical carbamazepine was used to identify septic-impacted groundwater in a coastal watershed. Using ultrahigh resolution mass spectrometry data, the nitrogen-containing features of the dissolved organic matter in septic-impacted and non-impacted samples were compared. The septic-impacted groundwater samples have a larger abundance of nitrogen-containing formulas. Impacted samples have additional DON features in the regions ascribed as ‘protein-like’ and ‘lipid-like’ in van Krevelen space and have more intense nitrogen-containing features in a specific region of a carbon versus mass plot. These features are potential indicators of dissolved organic nitrogen arising from septic effluents, and this work suggests that ultrahigh resolution mass spectrometry is a valuable tool to identify and characterize sources of DON.

Convergent evidence for widespread rock nitrogen sources in Earth's surface environment.

PubMed

Houlton, B Z; Morford, S L; Dahlgren, R A

2018-04-06

Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth's land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet's nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth's nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Regulation of nitrogen uptake and assimilation: Effects of nitrogen source, root-zone pH, and aerial CO2 concentration on growth and productivity of soybeans

NASA Technical Reports Server (NTRS)

Raper, C. D.; Tolley-Henry, L.

1989-01-01

An important feature of controlled-environment crop production systems such as those to be used for life support of crews during space exploration is the efficient utilization of nitrogen supplies. Making decisions about the best sources of these supplies requires research into the relationship between nitrogen source and the physiological processes which regulate vegetative and reproductive plant growth. Work done in four areas within this research objective is reported: (1) experiments on the effects of root-zone pH on preferential utilization of NO3(-) versus NH4(+) nitrogen; (2) investigation of processes at the whole-plant level that regulate nitrogen uptake; (3) studies of the effects of atmospheric CO2 and NO3(-) supply on the growth of soybeans; and (4) examination of the role of NO3(-) uptake in enhancement of root respiration.

Safe battery solvents

DOEpatents

Harrup, Mason K.; Delmastro, Joseph R.; Stewart, Frederick F.; Luther, Thomas A.

2007-10-23

An ion transporting solvent maintains very low vapor pressure, contains flame retarding elements, and is nontoxic. The solvent in combination with common battery electrolyte salts can be used to replace the current carbonate electrolyte solution, creating a safer battery. It can also be used in combination with polymer gels or solid polymer electrolytes to produce polymer batteries with enhanced conductivity characteristics. The solvents may comprise a class of cyclic and acyclic low molecular weight phosphazenes compounds, comprising repeating phosphorus and nitrogen units forming a core backbone and ion-carrying pendent groups bound to the phosphorus. In preferred embodiments, the cyclic phosphazene comprises at least 3 phosphorus and nitrogen units, and the pendent groups are polyethers, polythioethers, polyether/polythioethers or any combination thereof, and/or other groups preferably comprising other atoms from Group 6B of the periodic table of elements.

Hispanic women's preferences for breast health information: subjective cultural influences on source, message, and channel.

PubMed

Oetzel, John; De Vargas, Felicia; Ginossar, Tamar; Sanchez, Christina

2007-01-01

The purpose of this study was to investigate the influence of 3 subjective cultural variables--self-construals (independence and interdependence), ethnic identity (bicultural, assimilation, traditional, and marginal), and cultural health attributions (equity and behavioral-environmental attributions)--on source, message, and channel preferences for receiving breast health information by Hispanic women age 35 or older. Subjective cultural variables collectively accounted for 2% to 28% of the variance in communication preferences. In addition, several associations were discovered: (a) having an interdependent self-construal was associated positively with preferences for significant other as a source, family sources, fear messages, media channels, and face-to-face channels; (b) having a bicultural identity was associated positively with preferences for family sources and media channels, but negatively with a desire for no information; and (c) having a marginal identity and equity attributions were associated positively with preferences for fear messages and a desire for no information, but negatively with preferences for expert sources. These findings are discussed in the context of tailoring breast health information to Hispanic women using computer technology and entertainment-education.

SPARROW modeling of nitrogen sources and transport in rivers and streams of California and adjacent states, U.S.

USGS Publications Warehouse

Saleh, Dina; Domagalski, Joseph L.

2015-01-01

The SPARROW (SPAtially Referenced Regressions On Watershed attributes) model was used to evaluate the spatial distribution of total nitrogen (TN) sources, loads, watershed yields, and factors affecting transport and decay in the stream network of California and portions of adjacent states for the year 2002. The two major TN sources to local catchments on a mass basis were fertilizers and manure (51.7%) and wastewater discharge (15.9%). Other sources contributed < 12%. Fertilizer use is widespread in the Central Valley region of California, and also important in several other regions because of the diversity of California agriculture. Precipitation, sand content of surficial soils, wetlands, and tile drains were important for TN movement to stream reaches. Median streamflow in the study area is about 0.04 m3/s. Aquatic losses of nitrogen were found to be most important in intermittent and small to medium sized streams (0.2-14 m3/s), while larger streams showed less loss, and therefore are important for TN transport. Nitrogen loss in reservoirs was found to be insignificant, possibly because most of the larger ones are located upstream of nitrogen sources. The model was used to show loadings, sources, and tributary inputs to several major rivers. The information provided by the SPARROW model is useful for determining both the major sources contributing nitrogen to streams and the specific tributaries that transport the load.

Biomass production and secretion of hydrolytic enzymes are influenced by the structural complexity of the nitrogen source in Fusarium oxysporum and Aspergillus nidulans.

PubMed

da Silva, M C; Bertolini, M C; Ernandes, J R

2001-01-01

The structural complexity of the nitrogen sources strongly affects biomass production and secretion of hydrolytic enzymes in filamentous fungi. Fusarium oxysporum and Aspergillus nidulans were grown in media containing glucose or starch, and supplemented with a nitrogen source varying from a single ammonium salt (ammonium sulfate) to free amino acids (casamino acids), peptides (peptone) and protein (gelatin). In glucose, when the initial pH was adjusted to 5.0, for both microorganisms, higher biomass production occurred upon supplementation with a nitrogen source in the peptide form (peptone and gelatin). With a close to neutrality pH, biomass accumulation was lower only in the presence of the ammonium salt. When grown in starch, biomass accumulation and secretion of hydrolytic enzymes (amylolytic and proteolytic) by Fusarium also depended on the nature of the nitrogen supplement and the pH. When the initial pH was adjusted to 5.0, higher growth and higher amylolytic activities were detected in the media supplemented with peptone, gelatin and casamino acids. However, at pH 7.0, higher biomass accumulation and higher amylolytic activities were observed upon supplementation with peptone or gelatin. Ammonium sulfate and casamino acids induced a lower production of biomass, and a different level of amylolytic enzyme secretion: high in ammonium sulfate and low in casamino acids. Secretion of proteolytic activity was always higher in the media supplemented with peptone and gelatin. Aspergillus, when grown in starch, was not as dependent as Fusarium on the nature of nitrogen source or the pH. The results described in this work indicate that the metabolism of fungi is regulated not only by pH, but also by the level of structural complexity of the nitrogen source in correlation to the carbon source.

Fluorescently tuned nitrogen-doped carbon dots from carbon source with different content of carboxyl groups

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hao; Wang, Yun; Dai, Xiao

2015-08-01

In this study, fluorescent nitrogen-doped carbon dots (NCDs) were tuned via varying the sources with different number of carboxyl groups. Owing to the interaction between amino and carboxyl, more amino groups conjugate the surface of the NCDs by the source with more carboxyl groups. Fluorescent NCDs were tuned via varying the sources with different content of carboxyl groups. Correspondingly, the nitrogen content, fluorescence quantum yields and lifetime of NCDs increases with the content of carboxyl groups from the source. Furthermore, cytotoxicity assay and cell imaging test indicate that the resultant NCDs possess low cytotoxicity and excellent biocompatibility.

Watershed delineation and nitrogen source analysis for Bayou ...

EPA Pesticide Factsheets

Nutrient pollution in stormwater runoff from urbanized areas contributes to water quality degradation in streams and receiving waterbodies. Agriculture, population growth, and industrial activities are significant sources of nitrogen inputs for surface waters. Increased nitrogen loading stimulates eutrophication through algal blooms, which leads to an overall decrease in drinking water and aquatic habitat quality. Bayou Chico, a highly urbanized watershed in the Pensacola Bay system in northwest Florida, is a nutrient-impaired waterbody under management to reduce bacteria and nutrient loadings, in accordance with the Florida Department of Environmental Protection’s (FDEP) Basin Management Action Plan. Best management practices and green infrastructure (GI) throughout Bayou Chico help reduce nitrogen inputs by retaining and filtering water. GI can function as a nitrogen sink by sorption or infiltration into soils, sequestration into plant material, and denitrification through microbial processes. However, a better understanding of the efficiency of these systems is needed to better inform management practices on future nitrogen reduction. This project will address two issues relating to the presence of nitrogen in the Bayou Chico watershed: 1) the identification of specific nitrogen sources within urbanized areas, and 2) the potential rates of nitrogen removal and sequestration from GI and nitrogen transport throughout the bayou. To accomplish these goals, nitr

Atmospheric nitrogen deposition to China: A model analysis on nitrogen budget and critical load exceedance

NASA Astrophysics Data System (ADS)

Zhao, Yuanhong; Zhang, Lin; Chen, Youfan; Liu, Xuejun; Xu, Wen; Pan, Yuepeng; Duan, Lei

2017-03-01

We present a national-scale model analysis on the sources and processes of inorganic nitrogen deposition over China using the GEOS-Chem model at 1/2° × 1/3° horizontal resolution. Model results for 2008-2012 are evaluated with an ensemble of surface measurements of wet deposition flux and gaseous ammonia (NH3) concentration, and satellite measurements of tropospheric NO2 columns. Annual total inorganic nitrogen deposition fluxes are simulated to be generally less than 10 kg N ha-1 a-1 in western China (less than 2 kg N ha-1 a-1 over Tibet), 15-50 kg N ha-1 a-1 in eastern China, and 16.4 kg N ha-1 a-1 averaged over China. Annual total deposition to China is 16.4 Tg N, with 10.2 Tg N (62%) from reduced nitrogen (NHx) and 6.2 Tg N from oxidized nitrogen (NOy). Domestic anthropogenic sources contribute 86% of the total deposition; foreign anthropogenic sources 7% and natural sources 7%. Annually 23% of domestically emitted NH3 and 36% for NOx are exported outside the terrestrial land of China. We find that atmospheric nitrogen deposition is about half of the nitrogen input from fertilizer application (29.6 Tg N a-1), and is much higher than that from natural biological fixation (7.3 Tg N a-1) over China. A comparison of nitrogen deposition with critical load estimates for eutrophication indicates that about 15% of the land over China experiences critical load exceedances, demonstrating the necessity of nitrogen emission controls to avoid potential negative ecological effects.

Nutrient mass balance and trends, Mobile River Basin, Alabama, Georgia, and Mississippi

USGS Publications Warehouse

Harned, D.A.; Atkins, J.B.; Harvill, J.S.

2004-01-01

A nutrient mass balance - accounting for nutrient inputs from atmospheric deposition, fertilizer, crop nitrogen fixation, and point source effluents; and nutrient outputs, including crop harvest and storage - was calculated for 18 subbasins in the Mobile River Basin, and trends (1970 to 1997) were evaluated as part of the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program. Agricultural nonpoint nitrogen and phosphorus sources and urban nonpoint nitrogen sources are the most important factors associated with nutrients in this system. More than 30 percent of nitrogen yield in two basins and phosphorus yield in eight basins can be attributed to urban point source nutrient inputs. The total nitrogen yield (1.3 tons per square mile per year) for the Tombigbee River, which drains a greater percentage of agricultural (row crop) land use, was larger than the total nitrogen yield (0.99 tons per square mile per year) for the Alabama River. Decreasing trends of total nitrogen concentrations in the Tombigbee and Alabama Rivers indicate that a reduction occurred from 1975 to 1997 in the nitrogen contributions to Mobile Bay from the Mobile River. Nitrogen concentrations also decreased (1980 to 1995) in the Black Warrior River, one of the major tributaries to the Tombigbee River. Total phosphorus concentrations increased from 1970 to 1996 at three urban influenced sites on the Etowah River in Georgia. Multiple regression analysis indicates a distinct association between water quality in the streams of the Mobile River drainage basin and agricultural activities in the basin.

Rate and yield relationships in the production of xanthan gum by batch fermentations using complex and chemically defined growth media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pinches, A.; Pallent, L.J.

1986-10-01

Rate and yield information relating to biomass and product formation and to nitrogen, glucose and oxygen consumption are described for xanthan gum batch fermentations in which both chemically defined (glutamate nitrogen) and complex (peptone nitrogen) media are employed. Simple growth and product models are used for data interpretation. For both nitrogen sources, rate and yield parameter estimates are shown to be independent of initial nitrogen concentrations. For stationary phases, specific rates of gum production are shown to be independent of nitrogen source but dependent on initial nitrogen concentration. The latter is modeled empirically and suggests caution in applying simple productmore » models to xanthan gum fermentations. 13 references.« less

Arachidonic acid production by Mortierella alpina using raw crop materials.

PubMed

Cao, Ganggang; Guan, Zhengbing; Liu, Feixian G; Liao, Xiangru; Cai, Yujie

2015-01-01

Arachidonic acid (ARA) is one of the three essential fatty acids, and it is important for human body to keep healthy and is widely used. At present, expensive materials such as glucose and yeast extract are generally reported to be optimal for ARA production. A new cost-effective fermentation process including cheaper material for ARA production is of great significance. Feasibility of using corn meal and powdered soybean for fungal growth and lipid accumulation was evaluated by means of single factor test. N-hexadecane concentration was optimized, and the effect of temperature on biomass and ARA content was examined. Mortierella alpina made better use of the aforementioned material as carbon and nitrogen sources for both hyphae growth and ARA production compared with glucose and yeast extract. Maximal levels of 10.9 g/L ARA and 26.1 g/L total lipids were obtained when 66 g/L corn meal, 54 g/L soybean meal and 6% (v/v) n-hexadecane were supplemented. A temperature-shift strategy involved three steps, namely, 30°C (3 days) - 25°C (4 days) - 20°C (4 days), which further improved ARA production by 24.7%. Several factors such as carbon and nitrogen sources, temperature and dissolved oxygen had great influence on biomass and microbial oil production. Mortierella alpina preferred corn and soybean meal compared with glucose and yeast extract, which would surely alleviate the high cost of ARA production. Based on this study, the new process is both low cost and practicable.

Preferential Osmolyte Accumulation: a Mechanism of Osmotic Stress Adaptation in Diazotrophic Bacteria

PubMed Central

Madkour, Magdy A.; Smith, Linda Tombras; Smith, Gary M.

1990-01-01

A common cellular mechanism of osmotic-stress adaptation is the intracellular accumulation of organic solutes (osmolytes). We investigated the mechanism of osmotic adaptation in the diazotrophic bacteria Azotobacter chroococcum, Azospirillum brasilense, and Klebsiella pneumoniae, which are adversely affected by high osmotic strength (i.e., soil salinity and/or drought). We used natural-abundance 13C nuclear magnetic resonance spectroscopy to identify all the osmolytes accumulating in these strains during osmotic stress generated by 0.5 M NaCl. Evidence is presented for the accumulation of trehalose and glutamate in Azotobacter chroococcum ZSM4, proline and glutamate in Azospirillum brasilense SHS6, and trehalose and proline in K. pneumoniae. Glycine betaine was accumulated in all strains grown in culture media containing yeast extract as the sole nitrogen source. Alternative nitrogen sources (e.g., NH4Cl or casamino acids) in the culture medium did not result in measurable glycine betaine accumulation. We suggest that the mechanism of osmotic adaptation in these organisms entails the accumulation of osmolytes in hyperosmotically stressed cells resulting from either enhanced uptake from the medium (of glycine betaine, proline, and glutamate) or increased net biosynthesis (of trehalose, proline, and glutamate) or both. The preferred osmolyte in Azotobacter chroococcum ZSM4 shifted from glutamate to trehalose as a consequence of a prolonged osmotic stress. Also, the dominant osmolyte in Azospirillum brasilense SHS6 shifted from glutamate to proline accumulation as the osmotic strength of the medium increased. PMID:16348295

Use of stable isotopes of carbon, nitrogen, and sulfer to identify sources of nitrogen in surface waters in the Lower Susquehanna River basin, Pennsylvania

USGS Publications Warehouse

Cravotta, C.A.

1995-01-01

Stable isotopes of carbon (C), nitrogen (N), and sulfur (S) in nitrogen sources and nearby samples of topsoil, subsoil, runoff water, and stream water were measured to evaluate the feasibility of using isotopic data to identify nitrogen sources in stream water from forested, agricultural, or suburban land-use areas. Chemical and isotopic compositions were measured for six N-source types consisting of rain water, forest-leaf litter, synthetic fertilizer, farm-animal manure, municipal-sewage effluent and sludge, and septic-tank effluent and sludge. Compositions of topsoil, subsoil, runoff water, and stream water were measured to evaluate changes in compositions of transported N-containing materials near the N source. Animal manure, human waste (sewage plus septic), and forest-leaf litter can be distinguished on the basis of C; however, most N-sources can not be distinguished on the basis of N and S, owing to wide ranges of compositions and overlap among different N-source types. Although values of N for soil and runoff-water samples are qualitatively similar to those of the applied N source, values of C and S for runoff-water and stream-water samples appear to reflect the compositions of relatively large reservoirs of the elements in soil organic matter and minerals, respectively, and not the composition of the applied N source. Because of incomplete chemical transfor- mations, the ratio of organic carbon to total nitrogen for particulates in runoff or stream waters generally is lower than that for associated, nearby soils, and isotopic compositions commonly differ between particulate and dissolved fractions in the water.

Sources and sinks of nitrogen and phosphorus to a deep, oligotrophic lake, Lake Crescent, Olympic National Park, Washington

USGS Publications Warehouse

Moran, P.W.; Cox, S.E.; Embrey, S.S.; Huffman, R.L.; Olsen, T.D.; Fradkin, S.C.

2012-01-01

Lake Crescent, in Olympic National Park in the northwest corner of Washington State is a deep-water lake renowned for its pristine water quality and oligotrophic nature. To examine the major sources and sinks of nutrients (as total nitrogen, total phosphorus, and dissolved nitrate), a study was conducted in the Lake Crescent watershed. The study involved measuring five major inflow streams, the Lyre River as the major outflow, recording weather and climatic data, coring lake bed sediment, and analyzing nutrient chemistry in several relevant media over 14 months. Water samples for total nitrogen, total phosphorous, and dissolved nitrate from the five inflow streams, the outlet Lyre River, and two stations in the lake were collected monthly from May 2006 through May 2007. Periodic samples of shallow water from temporary sampling wells were collected at numerous locations around the lake. Concentrations of nutrients detected in Lake Crescent and tributaries were then applied to the water budget estimates to arrive at monthly and annual loads from various environmental components within the watershed. Other sources, such as leaf litter, pollen, or automobile exhaust were estimated from annual values obtained from various literature sources. This information then was used to construct a nutrient budget for total nitrogen and total phosphorus. The nitrogen budget generally highlights vehicle traffic-diesel trucks in particular-along U.S. Highway 101 as a potential major anthropogenic source of nitrogen compounds in the lake. In contrast, contribution of nitrogen compounds from onsite septic systems appears to be relatively minor related to the other sources identified.

Resolving the bulk δ 15N values of ancient human and animal bone collagen via compound-specific nitrogen isotope analysis of constituent amino acids

NASA Astrophysics Data System (ADS)

Styring, Amy K.; Sealy, Judith C.; Evershed, Richard P.

2010-01-01

Stable nitrogen isotope analysis is a fundamental tool in assessing dietary preferences and trophic positions within contemporary and ancient ecosystems. In order to assess more fully the dietary contributions to human tissue isotope values, a greater understanding of the complex biochemical and physiological factors which underpin bulk collagen δ 15N values is necessary. Determinations of δ 15N values of the individual amino acids which constitute bone collagen are necessary to unravel these relationships, since different amino acids display different δ 15N values according to their biosynthetic origins. A range of collagen isolates from archaeological faunal and human bone ( n = 12 and 11, respectively), representing a spectrum of terrestrial and marine protein origins and diets, were selected from coastal and near-coastal sites at the south-western tip of Africa. The collagens were hydrolysed and δ 15N values of their constituent amino acids determined as N-acetylmethyl esters (NACME) via gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The analytical approach employed accounts for 56% of bone collagen nitrogen. Reconstruction of bulk bone collagen δ 15N values reveals a 2‰ offset from bulk collagen δ 15N values which is attributable to the δ 15N value of the amino acids which cannot currently be determined by GC-C-IRMS, notably arginine which comprises 53% of the nitrogen unaccounted for (23% of the total nitrogen). The δ 15N values of individual amino acids provide insights into both the contributions of various amino acids to the bulk δ 15N value of collagen and the factors influencing trophic position and the nitrogen source at the base of the food web. The similarity in the δ 15N values of alanine, glutamate, proline and hydroxyproline reflects the common origin of their amino groups from glutamate. The depletion in the δ 15N value of threonine with increasing trophic level indicates a fundamental difference between the biosynthetic pathway of threonine and the other amino acids. The δ 15N value of phenylalanine does not change significantly with trophic level, reflecting its conservative nature as an essential amino acid, and thus represents the isotopic composition of the nitrogen at the base of the food web. Δ 15N Glu-Phe values in particular are shown to reflect trophic level nitrogen sources within a food web. In relation to the reconstruction of ancient human diet the contribution of marine and terrestrial protein are strongly reflected in Δ 15N Glu-Phe values. Differences in nitrogen metabolism are also shown to have an influence upon individual amino acid δ 15N values with Δ 15N Glu-Phe values emphasising differences between the different physiological adaptations. The latter is demonstrated in tortoises, which can excrete nitrogen in the form of uric acid and urea and display negative Δ 15N Glu-Phe values whereas those for marine and terrestrial mammals are positive. The findings amplify the potential advantages of compound-specific nitrogen isotope analysis in the study of nitrogen flow within food webs and in the reconstruction of past human diets.

Efficient Utilization of Waste Carbon Source for Advanced Nitrogen Removal of Landfill Leachate

PubMed Central

Yin, Wenjun; Tan, Fengxun

2017-01-01

A modified single sequencing batch reactor (SBR) was developed to remove the nitrogen of the real landfill leachate in this study. To take the full advantage of the SBR, stir phase was added before and after aeration, respectively. The new mechanism in this experiment could improve the removal of nitrogen efficiently by the utilization of carbon source in the raw leachate. This experiment adopts the SBR process to dispose of the real leachate, in which the COD and ammonia nitrogen concentrations were about 3800 mg/L and 1000 mg/L, respectively. Results showed that the removal rates of COD and total nitrogen were above 85% and 95%, respectively, and the effluent COD and total nitrogen were less than 500 mg/L and 40 mg/L under the condition of not adding any carbon source. Also, the specific nitrogen removal rate was 1.48 mgN/(h·gvss). In this process, polyhydroxyalkanoate (PHA) as a critical factor for the highly efficient nitrogen removal (>95%) was approved to be the primary carbon source in the sludge. Because most of the organic matter in raw water was used for denitrification, in the duration of this 160-day experiment, zero discharge of sludge was realized when the effluent suspended solids were 30–50 mg/L. PMID:29435456

Effect of Nitrogen Source on Growth and Trichloroethylene Degradation by Methane-Oxidizing Bacteria

PubMed Central

Chu, Kung-Hui; Alvarez-Cohen, Lisa

1998-01-01

The effect of nitrogen source on methane-oxidizing bacteria with respect to cellular growth and trichloroethylene (TCE) degradation ability were examined. One mixed chemostat culture and two pure type II methane-oxidizing strains, Methylosinus trichosporium OB3b and strain CAC-2, which was isolated from the chemostat culture, were used in this study. All cultures were able to grow with each of three different nitrogen sources: ammonia, nitrate, and molecular nitrogen. Both M. trichosporium OB3b and strain CAC-2 showed slightly lower net cellular growth rates and cell yields but exhibited higher methane uptake rates, levels of poly-β-hydroxybutyrate (PHB) production, and naphthalene oxidation rates when grown under nitrogen-fixing conditions. The TCE-degrading ability of each culture was measured in terms of initial TCE oxidation rates and TCE transformation capacities (mass of TCE degraded/biomass inactivated), measured both with and without external energy sources. Higher initial TCE oxidation rates and TCE transformation capacities were observed in nitrogen-fixing mixed, M. trichosporium OB3b, and CAC-2 cultures than in nitrate- or ammonia-supplied cells. TCE transformation capacities were found to correlate with cellular PHB content in all three cultures. The results of this study suggest that the nitrogen-fixing capabilities of methane-oxidizing bacteria can be used to select for high-activity TCE degraders for the enhancement of bioremediation in fixed-nitrogen-limited environments. PMID:9726896

Nitrogen attenuation of terrestrial carbon cycle response to global environmental factors

USGS Publications Warehouse

Jain, A.A.; Yang, Xiaojuan; Kheshgi, H.; McGuire, A. David; Post, W.; Kicklighter, David W.

2009-01-01

Nitrogen cycle dynamics have the capacity to attenuate the magnitude of global terrestrial carbon sinks and sources driven by CO2 fertilization and changes in climate. In this study, two versions of the terrestrial carbon and nitrogen cycle components of the Integrated Science Assessment Model (ISAM) are used to evaluate how variation in nitrogen availability influences terrestrial carbon sinks and sources in response to changes over the 20th century in global environmental factors including atmospheric CO2 concentration, nitrogen inputs, temperature, precipitation and land use. The two versions of ISAM vary in their treatment of nitrogen availability: ISAM-NC has a terrestrial carbon cycle model coupled to a fully dynamic nitrogen cycle while ISAM-C has an identical carbon cycle model but nitrogen availability is always in sufficient supply. Overall, the two versions of the model estimate approximately the same amount of global mean carbon uptake over the 20th century. However, comparisons of results of ISAM-NC relative to ISAM-C reveal that nitrogen dynamics: (1) reduced the 1990s carbon sink associated with increasing atmospheric CO2 by 0.53 PgC yr−1 (1 Pg = 1015g), (2) reduced the 1990s carbon source associated with changes in temperature and precipitation of 0.34 PgC yr−1 in the 1990s, (3) an enhanced sink associated with nitrogen inputs by 0.26 PgC yr−1, and (4) enhanced the 1990s carbon source associated with changes in land use by 0.08 PgC yr−1 in the 1990s. These effects of nitrogen limitation influenced the spatial distribution of the estimated exchange of CO2 with greater sink activity in high latitudes associated with climate effects and a smaller sink of CO2 in the southeastern United States caused by N limitation associated with both CO2 fertilization and forest regrowth. These results indicate that the dynamics of nitrogen availability are important to consider in assessing the spatial distribution and temporal dynamics of terrestrial carbon sources and sinks.

Nitrogen Source and Loading Data for EPA Estuary Data Mapper

EPA Science Inventory

Nitrogen source and loading data have been compiled and aggregated at the scale of estuaries and associated watersheds of the conterminous United States, using the spatial framework in EPA's Estuary Data Mapper (EDM) to provide system boundaries. Original sources of data include...

Sources and Trends of Nitrogen Loading to New England Estuaries

EPA Science Inventory

A database of nitrogen (N) loading components to estuaries of the conterminous United States has been developed through application of regional SPARROW models. The original SPARROW models predict average detrended loads by source based on average flow conditions and 2002 source t...

Nitrous oxide nitrification and denitrification 15N enrichment factors from Amazon forest soils.

PubMed

Pérez, Tibisay; Garcia-Montiel, Diana; Trumbore, Susan; Tyler, Stanley; de Camargo, Plínio; Moreira, Marcelo; Piccolo, Marisa; Cerri, Carlos

2006-12-01

The isotopic signatures of 15N and 18O in N2O emitted from tropical soils vary both spatially and temporally, leading to large uncertainty in the overall tropical source signature and thereby limiting the utility of isotopes in constraining the global N2O budget. Determining the reasons for spatial and temporal variations in isotope signatures requires that we know the isotope enrichment factors for nitrification and denitrification, the two processes that produce N2O in soils. We have devised a method for measuring these enrichment factors using soil incubation experiments and report results from this method for three rain forest soils collected in the Brazilian Amazon: soil with differing sand and clay content from the Tapajos National Forest (TNF) near Santarém, Pará, and Nova Vida Farm, Rondônia. The 15N enrichment factors for nitrification and denitrification differ with soil texture and site: -111 per thousand +/- 12 per thousand and -31 per thousand +/- 11 per thousand for a clay-rich Oxisol (TNF), -102 per thousand +/- 5 per thousand and -45 per thousand +/- 5 per thousand for a sandier Ultisol (TNF), and -10.4 per thousand +/- 3.5 per thousand (enrichment factor for denitrification) for another Ultisol (Nova Vida) soil, respectively. We also show that the isotopomer site preference (delta15Nalpha - delta15Nbeta, where alpha indicates the central nitrogen atom and beta the terminal nitrogen atom in N2O) may allow differentiation between processes of production and consumption of N2O and can potentially be used to determine the contributions of nitrification and denitrification. The site preferences for nitrification and denitrification from the TNF-Ultisol incubated soils are: 4.2 per thousand +/- 8.4 per thousand and 31.6 per thousand +/- 8.1 per thousand, respectively. Thus, nitrifying and denitrifying bacteria populations under the conditions of our study exhibit significantly different 15N site preference fingerprints. Our data set strongly suggests that N2O isotopomers can be used in concert with traditional N2O stable isotope measurements as constraints to differentiate microbial N2O processes in soil and will contribute to interpretations of the isotopic site preference N2O values found in the free troposphere.

Rapid solidification of metallic particulates

NASA Technical Reports Server (NTRS)

Grant, N. J.

1982-01-01

In order to maximize the heat transfer coefficient the most important variable in rapid solidification is the powder particle size. The finer the particle size, the higher the solidification rate. Efforts to decrease the particle size diameter offer the greatest payoff in attained quench rate. The velocity of the liquid droplet in the atmosphere is the second most important variable. Unfortunately the choices of gas atmospheres are sharply limited both because of conductivity and cost. Nitrogen and argon stand out as the preferred gases, nitrogen where reactions are unimportant and argon where reaction with nitrogen may be important. In gas atomization, helium offers up to an order of magnitude increase in solidification rate over argon and nitrogen. By contrast, atomization in vacuum drops the quench rate several orders of magnitude.

Nitrogen diffusion in hafnia and the impact of nitridation on oxygen and hydrogen diffusion: A first-principles study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sathiyanarayanan, Rajesh, E-mail: rajessat@in.ibm.com, E-mail: rajesh.sathiyanarayanan@gmail.com; Pandey, R. K.; Murali, K. V. R. M.

2015-01-21

Using first-principles simulations, we have computed incorporation energies and diffusion barriers of ammonia, the nitrogen molecule and atomic nitrogen in monoclinic hafnia (m-HfO{sub 2}). Our calculations show that ammonia is likely to dissociate into an NH{sub 2} molecular unit, whereas the nitrogen molecule remains as a molecule either in the interstitial space or at an oxygen lattice site. The lowest energy pathway for the diffusion of atomic nitrogen interstitials consists of the hopping of the nitrogen interstitial between neighboring three-coordinated lattice oxygen atoms that share a single Hf atom, and the barrier for such hops is determined by a switchingmore » mechanism. The substitutional nitrogen atom shows a preference for diffusion through the doubly positive oxygen vacancy-mediated mechanism. Furthermore, we have investigated the impact of nitrogen atoms on the diffusion barriers of oxygen and hydrogen interstitials in m-HfO{sub 2}. Our results show that nitrogen incorporation has a significant impact on the barriers for oxygen and hydrogen diffusion: nitrogen atoms attract oxygen and hydrogen interstitials diffusing in the vicinity, thereby slowing down (reducing) their diffusion (diffusion length)« less

Use of hydrolysates from Atlantic cod (Gadus morhua L.) viscera as a complex nitrogen source for lactic acid bacteria.

PubMed

Aspmo, Stein Ivar; Horn, Svein Jarle; Eijsink, Vincent G H

2005-07-01

Hydrolysates of cod viscera were tested as an alternative to commonly used complex nitrogen sources (peptones and/or extracts) for the type strains of the lactic acid bacteria Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus casei, Lactobacillus sakei and Pediococcus pentosaceus. Comparative studies with MRS-like media containing different nitrogen sources showed that all the fish hydrolysates performed equally well or better than commercial extracts/peptones for all selected lactic acid bacteria.

Flux balance analysis of ammonia assimilation network in E. coli predicts preferred regulation point.

PubMed

Wang, Lu; Lai, Luhua; Ouyang, Qi; Tang, Chao

2011-01-25

Nitrogen assimilation is a critical biological process for the synthesis of biomolecules in Escherichia coli. The central ammonium assimilation network in E. coli converts carbon skeleton α-ketoglutarate and ammonium into glutamate and glutamine, which further serve as nitrogen donors for nitrogen metabolism in the cell. This reaction network involves three enzymes: glutamate dehydrogenase (GDH), glutamine synthetase (GS) and glutamate synthase (GOGAT). In minimal media, E. coli tries to maintain an optimal growth rate by regulating the activity of the enzymes to match the availability of the external ammonia. The molecular mechanism and the strategy of the regulation in this network have been the research topics for many investigators. In this paper, we develop a flux balance model for the nitrogen metabolism, taking into account of the cellular composition and biosynthetic requirements for nitrogen. The model agrees well with known experimental results. Specifically, it reproduces all the (15)N isotope labeling experiments in the wild type and the two mutant (ΔGDH and ΔGOGAT) strains of E. coli. Furthermore, the predicted catalytic activities of GDH, GS and GOGAT in different ammonium concentrations and growth rates for the wild type, ΔGDH and ΔGOGAT strains agree well with the enzyme concentrations obtained from western blots. Based on this flux balance model, we show that GS is the preferred regulation point among the three enzymes in the nitrogen assimilation network. Our analysis reveals the pattern of regulation in this central and highly regulated network, thus providing insights into the regulation strategy adopted by the bacteria. Our model and methods may also be useful in future investigations in this and other networks.

Using Model Comparisons to Understand Sources of Nitrogen Delivered to US Coastal Areas

EPA Science Inventory

Nitrogen loading to water bodies can result in eutrophication-related hypoxia and degraded water quality. The relative contributions of different anthropogenic and natural sources of in-stream N cannot be directly measured at whole-watershed scales; hence, N source attribution e...

Different nitrogen sources change the transcriptome of welan gum-producing strain Sphingomonas sp. ATCC 31555.

PubMed

Xu, Xiaopeng; Nie, Zuoming; Zheng, Zhiyong; Zhu, Li; Zhang, Hongtao; Zhan, Xiaobei

2017-09-01

To reveal effects of different nitrogen sources on the expressions and functions of genes in Sphingomonas sp. ATCC 31555, it was cultivated in medium containing inorganic nitrogen (IN), organic nitrogen (ON), or inorganic-organic combined nitrogen (CN). Welan gum production and bacterial biomass were determined, and RNA sequencing (RNA-seq) was performed. Differentially expressed genes (DEGs) between the different ATCC 31555 groups were identified, and their functions were analyzed. Welan gum production and bacterial biomass were significantly higher in the ON and CN groups compared with those in the IN group. RNA-seq produced 660 unigenes, among which 488, 731, and 844 DEGs were identified between the IN vs. ON, IN vs. CN, and ON vs. CN groups, respectively. All the DEGs were related significantly to metabolic process and signal transduction. DEGs between the IN vs. CN and ON vs. CN groups were potentially associated with bacterial chemotaxis. Real-time PCR confirmed the expressions of selected DEGs. Organic nitrogen led to higher bacterial biomass and welan gum production than inorganic nitrogen, which might reflect differences in gene expression associated with metabolic process, signal transduction, and bacterial chemotaxis induced by different nitrogen sources.

Isotopic constraints on the source of Pluto's nitrogen and the history of atmospheric escape

NASA Astrophysics Data System (ADS)

Mandt, Kathleen E.; Mousis, Olivier; Luspay-Kuti, Adrienn

2016-10-01

The origin and evolution of nitrogen in solar system bodies is an important question for understanding processes that took place during the formation of the planets and solar system bodies. Pluto has an atmosphere that is 99% molecular nitrogen, but it is unclear if this nitrogen is primordial or derived from ammonia in the protosolar nebula. The nitrogen isotope ratio is an important tracer of the origin of nitrogen on solar system bodies, and can be used at Pluto to determine the origin of its nitrogen. After evaluating the potential impact of escape and photochemistry on Pluto's nitrogen isotope ratio (14N/15N), we find that if Pluto's nitrogen originated as N2 the current ratio in Pluto's atmosphere would be greater than 324 while it would be less than 157 if the source of Pluto's nitrogen were NH3. The New Horizons spacecraft successfully visited the Pluto system in July 2015 providing a potential opportunity to measure 14N/15N in N2.

Sources and distribution of nitrate in ground water at a farmed field irrigated with sewage treatment-plant effluent, Tallahassee, Florida

USGS Publications Warehouse

Berndt, M.P.

1990-01-01

The city of Tallahassee, Florida began applying sewage treatment-plant effluent to a sprayfield southeast of the city in 1980. Fertilizers containing inorganic nitrogen were also applied in conjunction with the operation of a commercial farm at this site. Analysis of groundwater in the surficial aquifer and the Upper Floridan aquifer have indicated that nitrate concentrations in some wells exceed the prescribed drinking water maximum contaminant level of 10 mg/L (nitrate as nitrogen). Nitrate concentrations greater than the maximum contaminant level were not detected in samples from monitoring wells outside the sprayfield boundary. Analyses of water from the unsaturated zone indicated that conversion of organic nitrogen and ammonia to nitrate was complete before the nitrogen- enriched water reached the water table. Groundwater samples from wells in the surficial and Upper Floridan aquifers less than 100 ft deep located inside sprayed areas had mean concentrations of nitrate much higher than samples from similar wells located outside sprayed areas at the southeast sprayfield. These shallow wells inside the sprayed areas were the only wells in which the maximum contaminant level for nitrate was exceeded. Analyses of the nitrogen isotope ratios in groundwater were used to determine whether the major source of nitrogen was treated sewage or fertilizers. The nitrogen isotope ratios in contaminated groundwater at the southeast sprayfield were compared to those at another sprayfield southwest of the city, where treated sewage was the sole source of nitrogen. Statistical analyses indicated a significant difference in the nitrogen isotope ratios at the two sites, indicating that both nitrogen sources are significant at the southeast sprayfield. (USGS)

Metabolic Engineering of the Regulators in Nitrogen Catabolite Repression To Reduce the Production of Ethyl Carbamate in a Model Rice Wine System

PubMed Central

Zhao, Xinrui; Zou, Huijun; Fu, Jianwei; Chen, Jian

2014-01-01

Rice wine has been one of the most popular traditional alcoholic drinks in China. However, the presence of potentially carcinogenic ethyl carbamate (EC) in rice wine has raised a series of food safety issues. During rice wine production, the key reason for EC formation is urea accumulation, which occurs because of nitrogen catabolite repression (NCR) in Saccharomyces cerevisiae. NCR represses urea utilization by retaining Gln3p in the cytoplasm when preferred nitrogen sources are present. In order to increase the nuclear localization of Gln3p, some possible phosphorylation sites on the nuclear localization signal were mutated and the nuclear localization regulation signal was truncated, and the disruption of URE2 provided an additional method of reducing urea accumulation. By combining these strategies, the genes involved in urea utilization (DUR1,2 and DUR3) could be significantly activated in the presence of glutamine. During shake flask fermentations of the genetically modified strains, very little urea accumulated in the medium. Furthermore, the concentrations of urea and EC were reduced by 63% and 72%, respectively, in a model rice wine system. Examination of the normal nutrients in rice wine indicated that there were few differences in fermentation characteristics between the wild-type strain and the genetically modified strain. These results show that metabolic engineering of the NCR regulators has great potential as a method for eliminating EC during rice wine production. PMID:24185848

Metabolic engineering of the regulators in nitrogen catabolite repression to reduce the production of ethyl carbamate in a model rice wine system.

PubMed

Zhao, Xinrui; Zou, Huijun; Fu, Jianwei; Zhou, Jingwen; Du, Guocheng; Chen, Jian

2014-01-01

Rice wine has been one of the most popular traditional alcoholic drinks in China. However, the presence of potentially carcinogenic ethyl carbamate (EC) in rice wine has raised a series of food safety issues. During rice wine production, the key reason for EC formation is urea accumulation, which occurs because of nitrogen catabolite repression (NCR) in Saccharomyces cerevisiae. NCR represses urea utilization by retaining Gln3p in the cytoplasm when preferred nitrogen sources are present. In order to increase the nuclear localization of Gln3p, some possible phosphorylation sites on the nuclear localization signal were mutated and the nuclear localization regulation signal was truncated, and the disruption of URE2 provided an additional method of reducing urea accumulation. By combining these strategies, the genes involved in urea utilization (DUR1,2 and DUR3) could be significantly activated in the presence of glutamine. During shake flask fermentations of the genetically modified strains, very little urea accumulated in the medium. Furthermore, the concentrations of urea and EC were reduced by 63% and 72%, respectively, in a model rice wine system. Examination of the normal nutrients in rice wine indicated that there were few differences in fermentation characteristics between the wild-type strain and the genetically modified strain. These results show that metabolic engineering of the NCR regulators has great potential as a method for eliminating EC during rice wine production.

A comparison of NEWS and SPARROW models to understand sources of nitrogen delivered to US coastal areas

EPA Science Inventory

The relative contributions of different anthropogenic and natural sources of in-stream nitrogen (N) cannot be directly measured at whole-watershed scales. Hence, source attribution estimates beyond the scale of small catchments must rely on models. Although such estimates have be...

Modeling pathways of riverine nitrogen and phosphorus in the Baltic Sea

NASA Astrophysics Data System (ADS)

Radtke, H.; Neumann, T.; Voss, M.; Fennel, W.

2012-09-01

A better understanding of the fate of nutrients entering the Baltic Sea ecosystem is an important issue with implications for environmental management. There are two sources of nitrogen and phosphorus: riverine input and atmospheric deposition. In the case of nitrogen, the fixation of dinitrogen by diazotrophic bacteria represents a third source. From an analysis of stable nitrogen isotope ratios it was suggested that most of the riverine nitrogen is sequestered in the coastal rim, specifically along the southern Baltic Sea coast with its coarse sediments, whereas nitrogen from fixation dominates the central basins. However, pathways of nutrients and timescales between the input of the nutrients and their arrival in different basins are difficult to obtain from direct measurements. To elucidate this problem, we use a source attribution technique in a three-dimensional ecosystem model, ERGOM, to track nutrients originating from various rivers. An “age” variable is attributed to the marked elements to indicate their propagation speeds and residence times. In this paper, we specifically investigate the spreading of nitrogen and phosphorus from the riverine discharges of the Oder, Vistula, Neman and Daugava. We demonstrate which regions they are transported to and for how long they remain in the ecosystem. The model results show good agreement with source estimations from observed δ15N values in sediments. The model results suggest that 95% of nitrogen is lost by denitrification in sediments, after an average time of 1.4 years for riverine nitrogen. The residence time of riverine phosphorus is much longer and exceeds our simulated period of 35 years.

Microbial utilization of nitrogen in cold core eddies: size does matter

NASA Astrophysics Data System (ADS)

McInnes, A.; Messer, L. F.; Laiolo, L.; Laverock, B.; Laczka, O.; Brown, M. V.; Seymour, J.; Doblin, M.

2016-02-01

As the base of the marine food web, and the first step in the biological carbon pump, understanding changes in microbial community composition is essential for predicting changes in the marine nitrogen (N) cycle. Climate change projections suggest that oligotrophic waters will become more stratified with a concomitant shift in microbial community composition based on changes in N supply. In regions of strong boundary currents, eddies could reduce this limitation through nutrient uplift and other forms of eddy mixing. Understanding the preference for different forms of N by microbes is essential for understanding and predicting shifts in the microbial community. This study aims to understand the utilization of different N species within different microbial size fractions as well as understand the preferred source of N to these groups across varying mesoscale and sub-mesoscale features in the East Australian Current (EAC). In June 2015 we sampled microbial communities from three depths (surface, chlorophyll-a maximum and below the mixed layer), in three mesoscale and sub-mesoscale eddy features, as well as two end-point water masses (coastal and oligotrophic EAC water). Particulate matter was analysed for stable C and N isotopes, and seawater incubations with trace amounts of 15NO3, 15NH4, 15N2, 15Urea and 13C were undertaken. All samples were size fractionated into 0.3-2.0 µm, 2.0-10 µm, and >10 µm size classes, encompassing the majority of microbes in these waters. Microbial community composition was also assessed (pigments, flow cytometry, DNA), as well as physical and chemical parameters, to better understand the drivers of carbon fixation and nitrogen utilization across a diversity of water masses and microbial size classes. We observed that small, young features have a greater abundance of larger size classes. We therefore predict that these microbes will preferentially draw down the recently pulsed NO3. Ultimately, the size and age of a feature will determine the N compound utilization and microbial community composition and as the feature grows in size and age a community succession will lead to differential more diverse N compound utilization.

Method for Providing Semiconductors Having Self-Aligned Ion Implant

NASA Technical Reports Server (NTRS)

Neudeck, Philip G. (Inventor)

2014-01-01

A method is disclosed that provides a self-aligned nitrogen-implant particularly suited for a Junction Field Effect Transistor (JFET) semiconductor device preferably comprised of a silicon carbide (SiC). This self-aligned nitrogen-implant allows for the realization of durable and stable electrical functionality of high temperature transistors such as JFETs. The method implements the self-aligned nitrogen-implant having predetermined dimensions, at a particular step in the fabrication process, so that the SiC junction field effect transistors are capable of being electrically operating continuously at 500.degree. C. for over 10,000 hours in an air ambient with less than a 10% change in operational transistor parameters.

Method for Providing Semiconductors Having Self-Aligned Ion Implant

NASA Technical Reports Server (NTRS)

Neudeck, Philip G. (Inventor)

2011-01-01

A method is disclosed that provides a self-aligned nitrogen-implant particularly suited for a Junction Field Effect Transistor (JFET) semiconductor device preferably comprised of a silicon carbide (SiC). This self-aligned nitrogen-implant allows for the realization of durable and stable electrical functionality of high temperature transistors such as JFETs. The method implements the self-aligned nitrogen-implant having predetermined dimensions, at a particular step in the fabrication process, so that the SiC junction field effect transistors are capable of being electrically operating continuously at 500.degree. C. for over 10,000 hours in an air ambient with less than a 10% change in operational transistor parameters.

Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

NASA Astrophysics Data System (ADS)

Zhao, Y.; Zhang, L.; Pan, Y.; Wang, Y.; Paulot, F.; Henze, D. K.

2015-09-01

Rapid Asian industrialization has led to increased downwind atmospheric nitrogen deposition threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2° × 2/3° horizontal resolution over East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a-1 as NH3 and 15.7 Tg N a-1 as NOx. China has the largest sources with 12.8 Tg N a-1 as NH3 and 7.9 Tg N a-1 as NOx; the high-NH3 emissions reflect its intensive agricultural activities. We find Asian NH3 emissions are a factor of 3 higher in summer than winter. The model simulation for 2008-2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8-20 kg N ha-1 a-1, decreasing rapidly downwind of the Asian continent. Deposition fluxes average 11.9 kg N ha-1 a-1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha-1 a-1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7 % over the South China Sea, and become important (greater than 30 %) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian monsoon and in nitrogen emissions. The model adjoint further estimates that nitrogen deposition to the Yellow Sea originates from sources over China (92 % contribution) and the Korean peninsula (7 %), and by sectors from fertilizer use (24 %), power plants (22 %), and transportation (18 %). Deposition to the South China Sea shows source contribution from mainland China (66 %), Taiwan (20 %), and the rest (14 %) from the southeast Asian countries and oceanic NH3 emissions. The adjoint analyses also indicate that reducing Asian NH3 emissions would increase NOy dry deposition to the Yellow Sea (28 % offset annually), limiting the effectiveness of NH3 emission controls on reducing nitrogen deposition to the Yellow Sea.

Methylamine as a nitrogen source for microorganisms from a coastal marine environment.

PubMed

Taubert, Martin; Grob, Carolina; Howat, Alexandra M; Burns, Oliver J; Pratscher, Jennifer; Jehmlich, Nico; von Bergen, Martin; Richnow, Hans H; Chen, Yin; Murrell, J Colin

2017-06-01

Nitrogen is a key limiting resource for biomass production in the marine environment. Methylated amines, released from the degradation of osmolytes, could provide a nitrogen source for marine microbes. Thus far, studies in aquatic habitats on the utilization of methylamine, the simplest methylated amine, have mainly focussed on the fate of the carbon from this compound. Various groups of methylotrophs, microorganisms that can grow on one-carbon compounds, use methylamine as a carbon source. Non-methylotrophic microorganisms may also utilize methylamine as a nitrogen source, but little is known about their diversity, especially in the marine environment. In this proof-of-concept study, stable isotope probing (SIP) was used to identify microorganisms from a coastal environment that assimilate nitrogen from methylamine. SIP experiments using 15 N methylamine combined with metagenomics and metaproteomics facilitated identification of active methylamine-utilizing Alpha- and Gammaproteobacteria. The draft genomes of two methylamine utilizers were obtained and their metabolism with respect to methylamine was examined. Both bacteria identified in these SIP experiments used the γ-glutamyl-methylamide pathway, found in both methylotrophs and non-methylotrophs, to metabolize methylamine. The utilization of 15 N methylamine also led to the release of 15 N ammonium that was used as nitrogen source by other microorganisms not directly using methylamine. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

SOURCES AND ESTIMATED LOAD OF BIOAVAILABLE NITROGEN ATTRIBUTABLE TO CHRONIC NITROGEN EXPOSURE AND CHANGED ECOSYSTEM STRUCTURE AND FUNCTION

EPA Science Inventory

Bioavailable nitrogen is a limiting nutrient throughout the Eastern United States. Research demonstrates that exposure to large doses of nitrogen leads to deleterious environmental impacts. However, effects of chronic exposure to lower doses of nitrogen are not well known. Since...

SOURCES AND ESTIMATED LOAD OF BIOAVAILABLE NITROGEN ATTRIBUTED TO CHRONIC NITROGEN EXPOSURE AND CHANGED ECOSYSTEM STRUCTURE AND FUNCTION

EPA Science Inventory

Bioavailable nitrogen is a limiting nutrient throughout the Eastern United States. Research demonstrates that exposure to large doses of nitrogen leads to deleterious environmental impacts. However, effects of chronic exposure to lower doses of nitrogen are under-appreciated. ...

The nitrogen footprint tool network: a multi-institution program to reduce nitrogen pollution

EPA Science Inventory

Anthropogenic sources of reactive nitrogen have local and global impacts on air and water quality and detrimental effects on human and ecosystem health. This paper uses the nitrogen footprint tool (NFT) to determine the amount of nitrogen (N) released as a result of institutional...

Aerobic Degradation of 2,4,6-Trinitrotoluene by Enterobacter cloacae PB2 and by Pentaerythritol Tetranitrate Reductase

PubMed Central

French, Christopher E.; Nicklin, Stephen; Bruce, Neil C.

1998-01-01

Enterobacter cloacae PB2 was originally isolated on the basis of its ability to utilize nitrate esters, such as pentaerythritol tetranitrate (PETN) and glycerol trinitrate, as the sole nitrogen source for growth. The enzyme responsible is an NADPH-dependent reductase designated PETN reductase. E. cloacae PB2 was found to be capable of slow aerobic growth with 2,4,6-trinitrotoluene (TNT) as the sole nitrogen source. Dinitrotoluenes were not produced and could not be used as nitrogen sources. Purified PETN reductase was found to reduce TNT to its hydride-Meisenheimer complex, which was further reduced to the dihydride-Meisenheimer complex. Purified PETN reductase and recombinant Escherichia coli expressing PETN reductase were able to liberate nitrogen as nitrite from TNT. The ability to remove nitrogen from TNT suggests that PB2 or recombinant organisms expressing PETN reductase may be useful for bioremediation of TNT-contaminated soil and water. PMID:9687442

Role of Nitrogen and Carbon Transport, Regulation, and Metabolism Genes for Saccharomyces cerevisiae Survival In Vivo†

PubMed Central

Kingsbury, Joanne M.; Goldstein, Alan L.; McCusker, John H.

2006-01-01

Saccharomyces cerevisiae is both an emerging opportunistic pathogen and a close relative of pathogenic Candida species. To better understand the ecology of fungal infection, we investigated the importance of pathways involved in uptake, metabolism, and biosynthesis of nitrogen and carbon compounds for survival of a clinical S. cerevisiae strain in a murine host. Potential nitrogen sources in vivo include ammonium, urea, and amino acids, while potential carbon sources include glucose, lactate, pyruvate, and fatty acids. Using mutants unable to either transport or utilize these compounds, we demonstrated that no individual nitrogen source was essential, while glucose was the most significant primary carbon source for yeast survival in vivo. Hydrolysis of the storage carbohydrate glycogen made a slight contribution for in vivo survival compared with a substantial requirement for trehalose hydrolysis. The ability to sense and respond to low glucose concentrations was also important for survival. In contrast, there was little or no requirement in vivo in this assay for any of the nitrogen-sensing pathways, nitrogen catabolite repression, the ammonium- or amino acid-sensing pathways, or general control. By using auxotrophic mutants, we found that some nitrogenous compounds (polyamines, methionine, and lysine) can be acquired from the host, while others (threonine, aromatic amino acids, isoleucine, and valine) must be synthesized by the pathogen. Our studies provide insights into the yeast-host environment interaction and identify potential antifungal drug targets. PMID:16682459

Isolation and Characterization of Anaerobic Bacteria for Symbiotic Recycling of Uric Acid Nitrogen in the Gut of Various Termites

PubMed Central

Thong-On, Arunee; Suzuki, Katsuyuki; Noda, Satoko; Inoue, Jun-ichi; Kajiwara, Susumu; Ohkuma, Moriya

2012-01-01

Recycling of the nitrogenous waste uric acid (UA) of wood-feeding termites by their gut bacteria is one of the significant aspects of symbiosis for the conservation of nitrogen sources. Diverse anaerobic UA-degrading bacteria comprising 16 species were isolated from the gut of eight termite species, and were assigned to Clostridia, Enterobacteriaceae, and low G+C Gram-positive cocci. UA-degrading Clostridia had never been isolated from termite guts. UA-degrading ability was sporadically distributed among phylogenetically various culturable anaerobic bacteria from termite guts. A strain of Clostridium sp., which was commonly isolated from three termite species and represented a probable new species in cluster XIVa of clostridia, utilized UA as a nitrogen source but not as a sole carbon and energy source. This feature is in clear contrast to that of well-studied purinolytic clostridia or previously isolated UA degraders from termite guts, which also utilize UA as a sole carbon and energy source. Ammonia is the major nitrogenous product of UA degradation. Various purines stimulated the growth of this strain when added to an otherwise growth-limiting, nitrogen poor medium. The bacterial species involved the recycling of UA nitrogen in the gut microbial community of termites are more diverse in terms of both taxonomy and nutritional physiology than previously recognized. PMID:22791052

Preference for tap, bottled, and recycled water: Relations to PTC taste sensitivity and personality.

PubMed

Harmon, Daniel; Gauvain, Mary; Z Reisz; Arthur, Isaac; Story, S Drew

2018-02-01

This study investigated people's preferences for different water sources and factors that predict such preferences using a blind taste test. Water preferences of 143 participants for one name-brand bottled water, one groundwater-sourced tap water, and one indirect potable reuse (IDR) water were assessed. For predictors of water preference, we measured each participant's PTC taste sensitivity and assessed two personality traits (Neuroticism, Openness to Experience). We also explored participants' descriptions of each water source. Results indicate a preference for water treated with Reverse Osmosis (RO) (bottled and IDR water) over groundwater-sourced water, which had higher pH levels and lower concentrations of Ca and HCO 3 - . PTC taste sensitivity did not predict preferences, while Openness to Experience and Neuroticism predicted preference for IDR water. Positive relations between Openness to Experience and preferences for bottled and IDR water were moderated by gender and were stronger among females. Participants described water primarily by its taste and texture. Findings suggest that (1) tap water treated by RO is equally preferable to some bottled water, (2) personality traits may affect water preferences, and (3) prior findings of gender differences in preferences for bottled water may reflect personality characteristics. Efforts to increase acceptance for sustainable water alternatives, such as IDR, may be more successful by assuring consumers about taste and addressing personality traits that encourage or inhibit use. Copyright © 2017 Elsevier Ltd. All rights reserved.

Urease Activity Represents an Alternative Pathway for Mycobacterium tuberculosis Nitrogen Metabolism

PubMed Central

Lin, Wenwei; Mathys, Vanessa; Ang, Emily Lei Yin; Koh, Vanessa Hui Qi; Martínez Gómez, Julia María; Ang, Michelle Lay Teng; Zainul Rahim, Siti Zarina; Tan, Mai Ping; Pethe, Kevin

2012-01-01

Urease represents a critical virulence factor for some bacterial species through its alkalizing effect, which helps neutralize the acidic microenvironment of the pathogen. In addition, urease serves as a nitrogen source provider for bacterial growth. Pathogenic mycobacteria express a functional urease, but its role during infection has yet to be characterized. In this study, we constructed a urease-deficient Mycobacterium tuberculosis strain and confirmed the alkalizing effect of the urease activity within the mycobacterium-containing vacuole in resting macrophages but not in the more acidic phagolysosomal compartment of activated macrophages. However, the urease-mediated alkalizing effect did not confer any growth advantage on M. tuberculosis in macrophages, as evidenced by comparable growth profiles for the mutant, wild-type (WT), and complemented strains. In contrast, the urease-deficient mutant exhibited impaired in vitro growth compared to the WT and complemented strains when urea was the sole source of nitrogen. Substantial amounts of ammonia were produced by the WT and complemented strains, but not with the urease-deficient mutant, which represents the actual nitrogen source for mycobacterial growth. However, the urease-deficient mutant displayed parental colonization profiles in the lungs, spleen, and liver in mice. Together, our data demonstrate a role for the urease activity in M. tuberculosis nitrogen metabolism that could be crucial for the pathogen's survival in nutrient-limited microenvironments where urea is the sole nitrogen source. Our work supports the notion that M. tuberculosis virulence correlates with its unique metabolic versatility and ability to utilize virtually any carbon and nitrogen sources available in its environment. PMID:22645285

Production of succinic acid from sugarcane molasses supplemented with a mixture of corn steep liquor powder and peanut meal as nitrogen sources by Actinobacillus succinogenes.

PubMed

Shen, N; Qin, Y; Wang, Q; Liao, S; Zhu, J; Zhu, Q; Mi, H; Adhikari, B; Wei, Y; Huang, R

2015-06-01

The potential of using corn steep liquor powder (CSLP), peanut meal (PM), soybean meal (SM), cotton meal (CM) and urea as the substitute of yeast extract (YE) as the nitrogen source was investigated for producing succinic acid (SA). Actinobacillus succinogenes GXAS137 was used as the fermenting bacterium and sugarcane molasses was used as the main substrate. None of these materials were able to produce SA as high as YE did. The CSLP could still be considered as a feasible and inexpensive alternate for YE as the yield of SA produced using CSLP was second only to the yield of SA obtained by YE. The use of CSLP-PM mixed formulation (CSLP to PM ratio = 2·6) as nitrogen source produced SA up to 59·2 g l(-1) with a productivity of 1·2 g l(-1) h(-1). A batch fermentation using a stirred bioreactor produced up to 60·7 g l(-1) of SA at the same formulation. Fed-batch fermentation that minimized the substrate inhibition produced 64·7 g l(-1) SA. These results suggest that sugarcane molasses supplemented with a mixture of CSLP and PM as the nitrogen source could be used to produce SA more economically using A. succinogenes. Significance and impact of the study: Succinic acid (SA) is commonly used as a platform chemical to produce a number of high value derivatives. Yeast extract (YE) is used as a nitrogen source to produce SA. The high cost of YE is currently the limiting factor for industrial production of SA. This study reports the use of a mixture of corn steep liquor powder (CSLP) and peanut meal (PM) as an inexpensive nitrogen source to substitute YE. The results showed that this CSLP-PM mixed formulation can be used as an effective and economic nitrogen source for the production of SA. © 2015 The Society for Applied Microbiology.

The effects of climate change on instream nitrogen transport in the contiguous United States

NASA Astrophysics Data System (ADS)

Alam, M. J.; Goodall, J. L.

2011-12-01

Excessive nitrogen loading has caused significant environmental impacts such as eutrophication and hypoxia in waterbodies around the world. Nitrogen loading is largely dependent on nonpoint source pollution and nitrogen transport from nonpoint source pollution is greatly impacted by climate conditions. For example, increased precipitation leads to more runoff and a higher nitrogen yield. However, higher temperatures also impact nitrogen transport in that higher temperatures increase denitrification and therefore reduce nitrogen yield. The purpose of this research is to quantify potential changes in nitrogen yield for the contiguous United States under predicted climate change scenarios, specifically changes in precipitation and air temperature. The analysis was performed for high (A2) and low (B1) emission scenarios and for the year 2030, 2050 and 2090. We used 11 different IPCC (The Intergovernmental Panel on Climate Change) models predicted precipitation and temperature estimates to capture uncertainty. The SPARROW model was calibrated using historical nitrogen loading data and used to predict nitrogen yields for future climate conditions. We held nitrogen source data constant in order to isolate the impact of predicted precipitation and temperature changes for each model scenario. Preliminary results suggest an overall decrease in nitrogen yield if climate change impacts are considered in isolation. For the A2 scenario, the model results indicated an overall incremental nitrogen yield decrease of 2-17% by the year 2030, 4-26% by the year 2050, and 11-45% by the year 2090. The B1 emission scenario also indicated an incremental yield decrease, but at lesser amounts of 2-18%, 5-21% and 10-38% by the years 2030, 2050, and 2090, respectively. This decrease is mainly due to higher predicted temperatures that result in increased denitrification rates.

Simultaneous nitrification and denitrification with different mixed nitrogen loads by a hypothermia aerobic bacterium.

PubMed

He, Tengxia; Li, Zhenlun; Xie, Deti; Sun, Quan; Xu, Yi; Ye, Qing; Ni, Jiupai

2018-04-01

Microorganism with simultaneous nitrification and denitrification ability plays a significant role in nitrogen removal process, especially in the eutrophic waters with excessive nitrogen loads. The nitrogen removal capacity of microorganism may suffer from low temperature or nitrite nitrogen source. In this study, a hypothermia aerobic nitrite-denitrifying bacterium, Pseudomonas tolaasii strain Y-11, was selected to determine the simultaneous nitrification and denitrification ability with mixed nitrogen source at 15 °C. The sole nitrogen removal efficiencies of strain Y-11 in simulated wastewater were obtained. After 24 h of incubation at 15 °C, the ammonium nitrogen fell below the detection limit from an initial value of 10.99 mg/L. Approximately 88.0 ± 0.33% of nitrate nitrogen was removed with the initial concentration of 11.78 mg/L and the nitrite nitrogen was not detected with the initial concentration of 10.75 mg/L after 48 h of incubation at 15 °C. Additionally, the simultaneous nitrification and denitrification nitrogen removal ability of P. tolaasii strain Y-11 was evaluated using low concentration of mixed NH 4 + -N and NO 3 - -N/NO 2 - -N (about 5 mg/L-N each) and high concentration of mixed NH 4 + -N and NO 3 - -N/NO 2 - -N (about 100 mg/L-N each). There was no nitrite nitrogen accumulation at the time of evaluation. The results demonstrated that P. tolaasii strain Y-11 had higher simultaneous nitrification and denitrification capacity with low concentration of mixed inorganic nitrogen sources and may be applied in low temperature wastewater treatment.

Tracking Nitrogen Sources, Transformation, and Transport at a Basin Scale with Complex Plain River Networks.

PubMed

Yi, Qitao; Chen, Qiuwen; Hu, Liuming; Shi, Wenqing

2017-05-16

This research developed an innovative approach to reveal nitrogen sources, transformation, and transport in large and complex river networks in the Taihu Lake basin using measurement of dual stable isotopes of nitrate. The spatial patterns of δ 15 N corresponded to the urbanization level, and the nitrogen cycle was associated with the hydrological regime at the basin level. During the high flow season of summer, nonpoint sources from fertilizer/soils and atmospheric deposition constituted the highest proportion of the total nitrogen load. The point sources from sewage/manure, with high ammonium concentrations and high δ 15 N and δ 18 O contents in the form of nitrate, accounted for the largest inputs among all sources during the low flow season of winter. Hot spot areas with heavy point source pollution were identified, and the pollutant transport routes were revealed. Nitrification occurred widely during the warm seasons, with decreased δ 18 O values; whereas great potential for denitrification existed during the low flow seasons of autumn and spring. The study showed that point source reduction could have effects over the short-term; however, long-term efforts to substantially control agriculture nonpoint sources are essential to eutrophication alleviation for the receiving lake, which clarifies the relationship between point and nonpoint source control.

Effects of nitrogen source availability and bioreactor operating strategies on lutein production with Scenedesmus obliquus FSP-3.

PubMed

Ho, Shih-Hsin; Xie, Youping; Chan, Ming-Chang; Liu, Chen-Chun; Chen, Chun-Yen; Lee, Duu-Jong; Huang, Chieh-Chen; Chang, Jo-Shu

2015-05-01

In this study, the effects of the type and concentration of nitrogen sources on the cell growth and lutein content of an isolated microalga Scenedesmus obliquus FSP-3 were investigated. With batch culture, the highest lutein content (4.61 mg/g) and lutein productivity (4.35 mg/L/day) were obtained when using 8.0 mM calcium nitrate as the nitrogen source. With this best nitrogen source condition, the microalgae cultivation was performed using two bioreactor strategies (namely, semi-continuous and two-stage operations) to further enhance the lutein content and productivity. Using semi-continuous operation with a 10% medium replacement ratio could obtain the highest biomass productivity (1304.8 mg/L/day) and lutein productivity (6.01 mg/L/day). This performance is better than most related studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Global distribution of alkyl nitrates and their impacts on reactive nitrogen in remote regions constrained by aircraft observations and chemical transport modeling

NASA Astrophysics Data System (ADS)

Fisher, J. A.; Atlas, E. L.; Blake, D. R.; Barletta, B.; Thompson, C. R.; Peischl, J.; Tzompa Sosa, Z. A.; Ryerson, T. B.; Murray, L. T.

2017-12-01

Nitrogen oxides (NO + NO­2 = NOx) are precursors in the formation of tropospheric ozone, contribute to the formation of aerosols, and enhance nitrogen deposition to ecosystems. While direct emissions tend to be localised over continental source regions, a significant source of NOx to the remote troposphere comes from degradation of other forms of reactive nitrogen. Long-lived, small chain alkyl nitrates (RONO2) including methyl, ethyl and propyl nitrates may be particularly significant forms of reactive nitrogen in the remote atmosphere as they are emitted directly by the ocean in regions where reactive nitrogen is otherwise very low. They also act as NOx reservoir species, sequestering NO­x in source regions and releasing it far downwind—and through this process may become increasingly important reservoirs as methane, ethane, and propane emissions grow. However, small RONO2 are not consistently included in global atmospheric chemistry models, and their distributions and impacts remain poorly constrained. In this presentation, we will describe a new RONO2 simulation in the GEOS-Chem chemical transport model evaluated using a large ensemble of aircraft observations collected over a 20-year period. The observations are largely concentrated over the Pacific Ocean, beginning with PEM-Tropics in the late 1990s and continuing through the recent HIPPO and ATom campaigns. Both observations and model show enhanced RONO2 in the tropical Pacific boundary layer that is consistent with a photochemical source in seawater. The model reproduces a similarly large enhancement over the southern ocean by assuming a large pool of oceanic RONO2 here, but the source of the seawater enhancement in this environment remains uncertain. We find that including marine RONO2 in the simulation is necessary to correct a large underestimate in simulated reactive nitrogen throughout the Pacific marine boundary layer. We also find that the impacts on NOx export from continental source regions are limited as RONO2 formation competes with other NO­x reservoirs such as PAN, leading to re-partitioning of reactive nitrogen rather than a net reactive nitrogen source. Further implications for NOx and ozone, as well as the impacts of recent changes in the global distribution of methane, ethane, propane, and NOx emissions, will also be discussed.

[Effects of carbon and nitrogen sources on 5-keto-gluconic acid production].

PubMed

Tan, Zhilei; Wang, Hongcui; Wei, Yuqiao; Li, Yanyan; Zhong, Cheng; Jia, Shiru

2014-01-01

Gluconobacter oxydans is known to oxidize glucose to gluconic acid (GA), and subsequently, to 2-keto-gluconic acid (2KGA) and 5-keto-gluconic acid (5KGA), while 5KGA can be converted to L-(+)-tartaric acid. In order to increase the production of 5KGA, Gluconobacter oxydans HGI-1 that converts GA to 5KGA exclusively was chosen in this study, and effects of carbon sources (lactose, maltose, sucrose, amylum and glucose) and nitrogen sources (yeast extract, fish meal, corn steep liquor, soybean meal and cotton-seed meal) on 5KGA production were investigated. Results of experiment in 500 mL shake-flask show that the highest yield of 5KGA (98.20 g/L) was obtained using 100 g/L glucose as carbon source. 5KGA reached 100.20 g/L, 109.10 g/L, 99.83 g/L with yeast extract, fish meal and corn steep liquor as nitrogen source respectively, among which the optimal nitrogen source was fish meal. The yield of 5KGA by corn steep liquor is slightly lower than that by yeast extract. For the economic reason, corn steep liquor was selected as nitrogen source and scaled up to 5 L stirred-tank fermentor, and the final concentration of 5KGA reached 93.80 g/L, with its maximum volumetric productivity of 3.48 g/(L x h) and average volumetric productivity of 1.56 g/(L x h). The result obtained in this study showed that carbon and nitrogen sourses for large-scale production of 5KGA by Gluconobacter oxydans HGI-1 were glucose and corn steep liquor, respectively, and the available glucose almost completely (85.93%) into 5KGA.

Aerobic biodegradation of the sulfonamide antibiotic sulfamethoxazole by activated sludge applied as co-substrate and sole carbon and nitrogen source.

PubMed

Müller, Elisabeth; Schüssler, Walter; Horn, Harald; Lemmer, Hilde

2013-08-01

Potential aerobic biodegradation mechanisms of the widely used polar, low-adsorptive sulfonamide antibiotic sulfamethoxazole (SMX) were investigated in activated sludge at bench scale. The study focused on (i) SMX co-metabolism with acetate and ammonium nitrate and (ii) SMX utilization when present as the sole carbon and nitrogen source. With SMX adsorption being negligible, elimination was primarily based on biodegradation. Activated sludge was able to utilize SMX both as a carbon and/or nitrogen source. SMX biodegradation was enhanced when a readily degradable energy supply (acetate) was provided which fostered metabolic activity. Moreover, it was raised under nitrogen deficiency conditions. The mass balance for dissolved organic carbon showed an incomplete SMX mineralization with two scenarios: (i) with SMX as a co-substrate, 3-amino-5-methyl-isoxazole represented the main stable metabolite and (ii) SMX as sole carbon and nitrogen source possibly yielded hydroxyl-N-(5-methyl-1,2-oxazole-3-yl)benzene-1-sulfonamide as a further metabolite. Copyright © 2013 Elsevier Ltd. All rights reserved.

Watershed nitrogen and phosphorus balance: The upper Potomac River basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaworski, N.A.; Groffman, P.M.; Keller, A.A.

1992-01-01

Nitrogen and phosphorus mass balances were estimated for the portion of the Potomac River basin watershed located above Washington, D.C. The total nitrogen (N) balance included seven input source terms, six sinks, and one 'change-in-storage' term, but was simplified to five input terms and three output terms. The phosphorus (P) baance had four input and three output terms. The estimated balances are based on watershed data from seven information sources. Major sources of nitrogen are animal waste and atmospheric deposition. The major sources of phosphorus are animal waste and fertilizer. The major sink for nitrogen is combined denitrification, volatilization, andmore » change-in-storage. The major sink for phosphorus is change-in-storage. River exports of N and P were 17% and 8%, respectively, of the total N and P inputs. Over 60% of the N and P were volatilized or stored. The major input and output terms on the budget are estimated from direct measurements, but the change-in-storage term is calculated by difference. The factors regulating retention and storage processes are discussed and research needs are identified.« less

Ionic composition and nitrate in drainage water from fields fertilized with different nitrogen sources, middle swamp watershed, North Carolina, August 2000-August 2001

USGS Publications Warehouse

Harden, Stephen L.; Spruill, Timothy B.

2004-01-01

A study was conducted from August 2000 to August 2001 to characterize the influence of fertilizer use from different nitrogen sources on the quality of drainage water from 11 subsurface tile drains and 7 surface field ditches in a North Carolina Coastal Plain watershed. Agricultural fields receiving commercial fertilizer (conventional sites), swine lagoon effluent (spray sites), and wastewater-treatment plant sludge (sludge site) in the Middle Swamp watershed were investigated. The ionic composition of drainage water in tile drains and ditches varied depending on fertilizer source type. The dominant ions identified in water samples from tile drains and ditches include calcium, magnesium, sodium, chloride, nitrate, and sulfate, with tile drains generally having lower pH, low or no bicarbonates, and higher nitrate and chloride concentrations. Based on fertilizer source type, median nitrate-nitrogen concentrations were significantly higher at spray sites (32.0 milligrams per liter for tiles and 8.2 milligrams per liter for ditches) relative to conventional sites (6.8 milligrams per liter for tiles and 2.7 milligrams per liter for ditches). The median instantaneous nitrate-nitrogen yields also were significantly higher at spray sites (420 grams of nitrogen per hectare per day for tile drains and 15.6 grams of nitrogen per hectare per day for ditches) relative to conventional sites (25 grams of nitrogen per hectare per day for tile drains and 8.1 grams of nitrogen per hectare per day for ditches). The tile drain site where sludge is applied had a median nitrate-nitrogen concentration of 10.5 milligrams per liter and a median instantaneous nitrate-nitrogen yield of 93 grams of nitrogen per hectare per day, which were intermediate to those of the conventional and spray tile drain sites. Results from this study indicate that nitrogen loadings and subsequent edge-of-field nitrate-nitrogen yields through tile drains and ditches were significantly higher at sites receiving applications of swine lagoon effluent compared to sites receiving commercial fertilizer.

Improvement of Nitrogen Assimilation and Fermentation Kinetics under Enological Conditions by Derepression of Alternative Nitrogen-Assimilatory Pathways in an Industrial Saccharomyces cerevisiae Strain

PubMed Central

Salmon, Jean-Michel; Barre, Pierre

1998-01-01

Metabolism of nitrogen compounds by yeasts affects the efficiency of wine fermentation. Ammonium ions, normally present in grape musts, reduce catabolic enzyme levels and transport activities for nonpreferred nitrogen sources. This nitrogen catabolite repression severely impairs the utilization of proline and arginine, both common nitrogen sources in grape juice that require the proline utilization pathway for their assimilation. We attempted to improve fermentation performance by genetic alteration of the regulation of nitrogen-assimilatory pathways in Saccharomyces cerevisiae. One mutant carrying a recessive allele of ure2 was isolated from an industrial S. cerevisiae strain. This mutation strongly deregulated the proline utilization pathway. Fermentation kinetics of this mutant were studied under enological conditions on simulated standard grape juices with various nitrogen levels. Mutant strains produced more biomass and exhibited a higher maximum CO2 production rate than the wild type. These differences were primarily due to the derepression of amino acid utilization pathways. When low amounts of dissolved oxygen were added, the mutants could assimilate proline. Biomass yield and fermentation rate were consequently increased, and the duration of the fermentation was substantially shortened. S. cerevisiae strains lacking URE2 function could improve alcoholic fermentation of natural media where proline and other poorly assimilated amino acids are the major potential nitrogen source, as is the case for most fruit juices and grape musts. PMID:9758807

Transient simulations of nitrogen load for a coastal aquifer and embayment, Cape Cod, MA

USGS Publications Warehouse

Colman, J.A.; Masterson, J.P.

2008-01-01

A time-varying, multispecies, modular, three-dimensional transport model (MT3DMS) was developed to simulate groundwater transport of nitrogen from increasing sources on land to the shore of Nauset Marsh, a coastal embayment of the Cape Cod National Seashore. Simulated time-dependent nitrogen loads at the coast can be used to correlate with current observed coastal eutrophic effects, to predict current and ultimate effects of development, and to predict loads resulting from source remediation. A time-varying nitrogen load, corrected for subsurface loss, was applied to the land subsurface in the transport model based on five land-use coverages documenting increasing development from 1951 to 1999. Simulated nitrogen loads to Nauset Marsh increased from 230 kg/yr before 1930 to 4390 kg/yr in 2001 to 7130 kg/yr in 2100, assuming future nitrogen sources constant at the 1999 land-use rate. The simulated nitrogen load per area of embayment was 5 times greater for Salt Pond, a eutrophic landward extension of Nauset Marsh, than for other Nauset Marsh areas. Sensitivity analysis indicated that load results were little affected by changes in vertical discretization and annual recharge but much affected by the nitrogen loss rate assumed for a kettle lake downgradient from a landfill.

Management of Multiple Nitrogen Sources during Wine Fermentation by Saccharomyces cerevisiae.

PubMed

Crépin, Lucie; Truong, Nhat My; Bloem, Audrey; Sanchez, Isabelle; Dequin, Sylvie; Camarasa, Carole

2017-03-01

During fermentative growth in natural and industrial environments, Saccharomyces cerevisiae must redistribute the available nitrogen from multiple exogenous sources to amino acids in order to suitably fulfill anabolic requirements. To exhaustively explore the management of this complex resource, we developed an advanced strategy based on the reconciliation of data from a set of stable isotope tracer experiments with labeled nitrogen sources. Thus, quantifying the partitioning of the N compounds through the metabolism network during fermentation, we demonstrated that, contrary to the generally accepted view, only a limited fraction of most of the consumed amino acids is directly incorporated into proteins. Moreover, substantial catabolism of these molecules allows for efficient redistribution of nitrogen, supporting the operative de novo synthesis of proteinogenic amino acids. In contrast, catabolism of consumed amino acids plays a minor role in the formation of volatile compounds. Another important feature is that the α-keto acid precursors required for the de novo syntheses originate mainly from the catabolism of sugars, with a limited contribution from the anabolism of consumed amino acids. This work provides a comprehensive view of the intracellular fate of consumed nitrogen sources and the metabolic origin of proteinogenic amino acids, highlighting a strategy of distribution of metabolic fluxes implemented by yeast as a means of adapting to environments with changing and scarce nitrogen resources. IMPORTANCE A current challenge for the wine industry, in view of the extensive competition in the worldwide market, is to meet consumer expectations regarding the sensory profile of the product while ensuring an efficient fermentation process. Understanding the intracellular fate of the nitrogen sources available in grape juice is essential to the achievement of these objectives, since nitrogen utilization affects both the fermentative activity of yeasts and the formation of flavor compounds. However, little is known about how the metabolism operates when nitrogen is provided as a composite mixture, as in grape must. Here we quantitatively describe the distribution through the yeast metabolic network of the N moieties and C backbones of these nitrogen sources. Knowledge about the management of a complex resource, which is devoted to improvement of the use of the scarce N nutrient for growth, will be useful for better control of the fermentation process and the sensory quality of wines. Copyright © 2017 American Society for Microbiology.

Management of Multiple Nitrogen Sources during Wine Fermentation by Saccharomyces cerevisiae

PubMed Central

Crépin, Lucie; Truong, Nhat My; Bloem, Audrey; Sanchez, Isabelle; Dequin, Sylvie

2017-01-01

ABSTRACT During fermentative growth in natural and industrial environments, Saccharomyces cerevisiae must redistribute the available nitrogen from multiple exogenous sources to amino acids in order to suitably fulfill anabolic requirements. To exhaustively explore the management of this complex resource, we developed an advanced strategy based on the reconciliation of data from a set of stable isotope tracer experiments with labeled nitrogen sources. Thus, quantifying the partitioning of the N compounds through the metabolism network during fermentation, we demonstrated that, contrary to the generally accepted view, only a limited fraction of most of the consumed amino acids is directly incorporated into proteins. Moreover, substantial catabolism of these molecules allows for efficient redistribution of nitrogen, supporting the operative de novo synthesis of proteinogenic amino acids. In contrast, catabolism of consumed amino acids plays a minor role in the formation of volatile compounds. Another important feature is that the α-keto acid precursors required for the de novo syntheses originate mainly from the catabolism of sugars, with a limited contribution from the anabolism of consumed amino acids. This work provides a comprehensive view of the intracellular fate of consumed nitrogen sources and the metabolic origin of proteinogenic amino acids, highlighting a strategy of distribution of metabolic fluxes implemented by yeast as a means of adapting to environments with changing and scarce nitrogen resources. IMPORTANCE A current challenge for the wine industry, in view of the extensive competition in the worldwide market, is to meet consumer expectations regarding the sensory profile of the product while ensuring an efficient fermentation process. Understanding the intracellular fate of the nitrogen sources available in grape juice is essential to the achievement of these objectives, since nitrogen utilization affects both the fermentative activity of yeasts and the formation of flavor compounds. However, little is known about how the metabolism operates when nitrogen is provided as a composite mixture, as in grape must. Here we quantitatively describe the distribution through the yeast metabolic network of the N moieties and C backbones of these nitrogen sources. Knowledge about the management of a complex resource, which is devoted to improvement of the use of the scarce N nutrient for growth, will be useful for better control of the fermentation process and the sensory quality of wines. PMID:28115380

Forensic applications of nitrogen and oxygen isotopes in tracing nitrate sources in urban environments

USGS Publications Warehouse

Silva, S.R.; Ging, P.B.; Lee, R.W.; Ebbert, J.C.; Tesoriero, A.J.; Inkpen, E.L.

2002-01-01

Ground and surface waters in urban areas are susceptible to nitrate contamination from septic systems, leaking sewer lines, and fertilizer applications. Source identification is a primary step toward a successful remediation plan in affected areas. In this respect, nitrogen and oxygen isotope ratios of nitrate, in conjunction with hydrologic data and water chemistry, have proven valuable in urban studies from Austin, Texas, and Tacoma, Washington. In Austin, stream water was sampled during stremflow and baseflow conditions to assess surface and subsurface sources of nitrate, respectively. In Tacoma, well waters were sampled in adjacent sewered and un-sewered areas to determine if locally high nitrate concentrations were caused by septic systems in the un-sewered areas. In both studies, sewage was identified as a nitrate source and mixing between sewage and other sources of nitrate was apparent. In addition to source identification, combined nitrogen and oxygen isotopes were important in determining the significance of denitrification, which can complicate source assessment by reducing nitrate concentrations and increasing ??15N values. The two studies illustrate the value of nitrogen and oxygen isotopes of nitrate for forensic applications in urban areas. ?? Published by Elsevier Science Ltd. on behalf of AEHS.

Quantitative identification of nitrate pollution sources and uncertainty analysis based on dual isotope approach in an agricultural watershed.

PubMed

Ji, Xiaoliang; Xie, Runting; Hao, Yun; Lu, Jun

2017-10-01

Quantitative identification of nitrate (NO 3 - -N) sources is critical to the control of nonpoint source nitrogen pollution in an agricultural watershed. Combined with water quality monitoring, we adopted the environmental isotope (δD-H 2 O, δ 18 O-H 2 O, δ 15 N-NO 3 - , and δ 18 O-NO 3 - ) analysis and the Markov Chain Monte Carlo (MCMC) mixing model to determine the proportions of riverine NO 3 - -N inputs from four potential NO 3 - -N sources, namely, atmospheric deposition (AD), chemical nitrogen fertilizer (NF), soil nitrogen (SN), and manure and sewage (M&S), in the ChangLe River watershed of eastern China. Results showed that NO 3 - -N was the main form of nitrogen in this watershed, accounting for approximately 74% of the total nitrogen concentration. A strong hydraulic interaction existed between the surface and groundwater for NO 3 - -N pollution. The variations of the isotopic composition in NO 3 - -N suggested that microbial nitrification was the dominant nitrogen transformation process in surface water, whereas significant denitrification was observed in groundwater. MCMC mixing model outputs revealed that M&S was the predominant contributor to riverine NO 3 - -N pollution (contributing 41.8% on average), followed by SN (34.0%), NF (21.9%), and AD (2.3%) sources. Finally, we constructed an uncertainty index, UI 90 , to quantitatively characterize the uncertainties inherent in NO 3 - -N source apportionment and discussed the reasons behind the uncertainties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Plants can use protein as a nitrogen source without assistance from other organisms

PubMed Central

Paungfoo-Lonhienne, Chanyarat; Lonhienne, Thierry G. A.; Rentsch, Doris; Robinson, Nicole; Christie, Michael; Webb, Richard I.; Gamage, Harshi K.; Carroll, Bernard J.; Schenk, Peer M.; Schmidt, Susanne

2008-01-01

Nitrogen is quantitatively the most important nutrient that plants acquire from the soil. It is well established that plant roots take up nitrogen compounds of low molecular mass, including ammonium, nitrate, and amino acids. However, in the soil of natural ecosystems, nitrogen occurs predominantly as proteins. This complex organic form of nitrogen is considered to be not directly available to plants. We examined the long-held view that plants depend on specialized symbioses with fungi (mycorrhizas) to access soil protein and studied the woody heathland plant Hakea actites and the herbaceous model plant Arabidopsis thaliana, which do not form mycorrhizas. We show that both species can use protein as a nitrogen source for growth without assistance from other organisms. We identified two mechanisms by which roots access protein. Roots exude proteolytic enzymes that digest protein at the root surface and possibly in the apoplast of the root cortex. Intact protein also was taken up into root cells most likely via endocytosis. These findings change our view of the spectrum of nitrogen sources that plants can access and challenge the current paradigm that plants rely on microbes and soil fauna for the breakdown of organic matter. PMID:18334638

Effect of the addition of nitrogen sources to cassava fiber and carbon-to-nitrogen ratios on Agaricus brasiliensis growth.

PubMed

Mantovani, T R D; Linde, G A; Colauto, N B

2007-01-01

The same substratum formulation to grow Agaricus bisporus has been used to grow Agaricus brasiliensis since its culture started in Brazil. Despite being different species, many of the same rules have been used for composting or axenic cultivation when it comes to nitrogen content and source in the substrate. The aim of this study was to verify the mycelial growth of A. brasiliensis in different ammonium sulfate and (or) urea concentrations added to cassava fiber and different carbon-to-nitrogen (C:N) ratios to increase the efficiency of axenic cultivation. Two nitrogen sources (urea and (or) ammonium sulfate) added to cassava fiber were tested for the in vitro mycelial growth in different C:N ratios (ranging from 2.5:l to 50:l) in the dark at 28 degrees C. The radial mycelial growth was measured after 8 days of growth and recorded photographically at the end of the experiment. Nitrogen from urea enhanced fungal growth better than ammonium sulfate or any mixture of nitrogen. The best C:N ratios for fungal growth were from 10:l to 50:l; C:N ratios below 10:l inhibited fungal growth.

Nitrogen extraction potential of wild and cultured bivalves harvested from nearshore waters of Cape Cod, USA.

PubMed

Reitsma, Joshua; Murphy, Diane C; Archer, Abigail F; York, Richard H

2017-03-15

As nitrogen entering coastal waters continues to be an issue, much attention has been generated to identify potential options that may help alleviate this stressor to estuaries, including the propagation of bivalves to remove excess nitrogen. Oysters (Crassostrea virginica) and quahogs (Mercenaria mercenaria) from numerous Cape Cod, MA, (USA) sources were analyzed for nitrogen content stored in tissues that would represent a net removal of nitrogen from a water body if harvested. Results showed local oysters average 0.69% nitrogen by total dry weight (mean 0.28gN/animal) and quahogs average 0.67% nitrogen by total dry weight (mean 0.22gN/animal); however, these values did vary by season and to a lesser extent by location or grow-out method. The differences in nitrogen content were largely related to the mass of shell or soft tissue. Nitrogen isotope data indicate shellfish from certain water bodies in the region are incorporating significant amounts of nitrogen from anthropogenic sources. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Nitrogen dynamics in the tidal freshwater Potomac River, Maryland and Virginia, water years 1979-81

USGS Publications Warehouse

Shultz, David J.

1989-01-01

On an annual basis, river-supplied nitrate is the predominant form of nitrogen supplied to the tidal Potomac River from external sources. Much of the nitrate is associated with high flows that have rapid transit times through the tidal river. The Blue Plains Sewage-Treatment Plant (STP) at Washington, D.C., is the greatest source of all nitrogen species during low-flow periods. Prior to the fall of 1980, ammonia concentrations in depth-integrated, composited water samples were greatest (more than 1.00 mg/L (milligram per liter) as nitrogen) during summer periods near Alexandria, Va., because of loading from the nearby Blue Plains STP and reduced river discharge. After the fall of 1980, initiation of advanced wastewater treatment at the Blue Plains STP reduced ammonia loading to the river by 90 percent and increased nitrate loading by a similar percentage. As a result, concentrations of ammonia during the 1981 low-flow period were less than 0.20 mg/L as nitrogen at Alexandria, while nitrate concentrations were greater than 1.50 mg/L as nitrogen. Concentrations of ammonia and nitrate at Alexandria were shown to be reasonably predictable by use of a simple dilution model that considers only loading from Chain Bridge and the Blue Plains STP. This apparently is the result of the short residence time through the Chain Bridge-to-Alexandria section of the tidal Potomac River, which precludes significant biological alterations. In marked contrast, the residence times of water parcels in the tidal Potomac River from Alexandria to Quantico, Va., are much greater because of the geometry of the reach. Biological nitrogen-cycle transformation processes affect nitrogen-species concentrations to a greater extent in this reach, especially during summer low-flow periods. Mass-balance calculations that separate changes in transport mass from biological transformations indicatethat the tidal Potomac River was a net sink for all the nitrogen constituents during the 1980 and 1981 summer low-flow periods. However, during the 1980-81 winter period, some ammonia and nitrate was transported out of the tidal Potomac River into the transition zone. Despite the reduced availability of ammonia, nitrogen-15 uptake studies showed that phytoplankton preferred ammonia to nitrate unless ammonia concentrations were less than 0.10 mg/L as nitrogen. Nitrification-rate studies during 1981 using a carbon-14 uptake technique indicate that rates did not vary with sample location, except for one sample from the head of the tidal river, where the rates were much higher. The numbers of Nitrobacter bacteria were highest in samples from near the Blue Plains STP and were greater than the numbers of Nitrosomonas bacteria. The predominance of Nitrobacter bacteria seemed to be associated with advanced wastewater treatment at the Blue Plains STP. Before advanced wastewater treatment, Nitrosomonas were numerically predominant and had the largest numbers near the Blue Plains STP. These results could be due to (1) loading of nitrifying bacteria in the Blue Plains sewage effluent that had been inhibited from further growth by an inhibitory substance or (2) the method used to measure nitrification rates, which measured only the ammonia oxidation stage; it is not possible to reject either mechanism on the basis of the data available. Process models were used in conjunction with mass-balance determinations and individual process studies to estimate rates of processes that were not directly measured. It is estimated that denitrification removed 10 times as much nitrate from the water column during the summer of 1981 as during the summer of 1980. Sedimentation of particulate nitrogen is estimated to be the largest sink for nitrogen from the water column and was approximately equal to the external annual loading of all nitrogen constituents on a daily basis. In summer, when river flows usually are low, the tidal Potomac River appears to be a partially closed system rather tha

Real-time continuous nitrate monitoring in Illinois in 2013

USGS Publications Warehouse

Warner, Kelly L.; Terrio, Paul J.; Straub, Timothy D.; Roseboom, Donald; Johnson, Gary P.

2013-01-01

Many sources contribute to the nitrogen found in surface water in Illinois. Illinois is located in the most productive agricultural area in the country, and nitrogen fertilizer is commonly used to maximize corn production in this area. Additionally, septic/wastewater systems, industrial emissions, and lawn fertilizer are common sources of nitrogen in urban areas of Illinois. In agricultural areas, the use of fertilizer has increased grain production to meet the needs of a growing population, but also has resulted in increases in nitrogen concentrations in many streams and aquifers (Dubrovsky and others, 2010). The urban sources can increase nitrogen concentrations, too. The Federal limit for nitrate nitrogen in water that is safe to drink is 10 milligrams per liter (mg/L) (http://water.epa.gov/drink/contaminants/basicinformation/nitrate.cfm, accessed on May 24, 2013). In addition to the concern with nitrate nitrogen in drinking water, nitrogen, along with phosphorus, is an aquatic concern because it feeds the intensive growth of algae that are responsible for the hypoxic zone in the Gulf of Mexico. The largest nitrogen flux to the waters feeding the Gulf of Mexico is from Illinois (Alexander and others, 2008). Most studies of nitrogen in surface water and groundwater include samples for nitrate nitrogen collected weekly or monthly, but nitrate concentrations can change rapidly and these discrete samples may not capture rapid changes in nitrate concentrations that can affect human and aquatic health. Continuous monitoring for nitrate could inform scientists and water-resource managers of these changes and provide information on the transport of nitrate in surface water and groundwater.

[Effect of carbon and nitrogen sources and complex B vitamins on the synthesis of alkaline protease by different strains of Bacillus mesentericus and Bacillus subtilis].

PubMed

Emtseva, T V

1975-01-01

The effect of different sources of carbon, nitrogen, amino acids and vitamins on the synthesis of alkaline proteases by the stock and mutant strains of Bacillus mesentericus and by the natural strain of Bacillus subtilis-12 has been investigated. The maximum synthesis of alkaline protease has been obtained in the media containing starch or its hydrolysates--dextrine and maltose as the carbon source. Ammonium phosphate and casein as the nitrogen source prove to be optimal for Bac. mesentericus and Bac. subtilis, respectively. Complex B vitamins added to the nutrient medium accelerate the enzyme synthesis 2.5-4-fold.

Using d15 N in Fish Larvae as an Indicator of Watershed Sources of Anthropogenic Nitrogen: Response at Multiple Spatial Scales

EPA Science Inventory

The nitrogen stable isotope, 15N, is an effective tool to track anthropogenic N sources to aquatic ecosystems. It may be difficult to identify potential N sources, however, where 15N responds similarly to multiple, concurrent activities in the watershed that cause higher nutrient...

Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

NASA Astrophysics Data System (ADS)

Zhao, Yuanhong; Zhang, Lin; Pan, Yuepeng; Wang, Yuesi; Paulot, Fabien; Henze, Daven

2016-04-01

Rapid Asian industrialization has lead to increased atmospheric nitrogen deposition downwind threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2°× 2/3° horizontal resolution over the East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a-1 as NH3 and 15.7 Tg N a-1 as NOx. China has the largest sources with 12.8 Tg N a-1 as NH3 and 7.9 Tg N a-1 as NOx; the much higher NH3 emissions reflect its intensive agricultural activities. We improve the seasonality of Asian NH3 emissions; emissions are a factor of 3 higher in summer than winter. The model simulation for 2008-2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8-20 kg N ha-1 a-1, decreasing rapidly downwind the Asian continent. Deposition fluxes average 11.9 kg N ha-1 a-1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha-1 a-1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7% over the South China Sea, and become important (greater than 30%) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian Monsoon and in nitrogen emissions. The model adjoint further points out that nitrogen deposition to the Yellow Sea originates from sources over China (92% contribution) and the Korean peninsula (7%), and by sectors from fertilizer use (24%), power plants (22%), and transportation (18%). Deposition to the South China Sea shows source contribution from Mainland China (64%), Taiwan (21%), and the rest 15% from the Southeast Asian countries and oceanic NH3 emissions. The adjoint analyses also indicate that reducing Asian NH3 emissions would increase NOy dry deposition to the Yellow Sea (28% offset annually), limiting the effectiveness of NH3 emission controls.

Carbon: Nitrogen Interaction Regulates Expression of Genes Involved in N-Uptake and Assimilation in Brassica juncea L.

PubMed Central

Goel, Parul; Bhuria, Monika; Kaushal, Mamta

2016-01-01

In plants, several cellular and metabolic pathways interact with each other to regulate processes that are vital for their growth and development. Carbon (C) and Nitrogen (N) are two main nutrients for plants and coordination of C and N pathways is an important factor for maintaining plant growth and development. In the present work, influence of nitrogen and sucrose (C source) on growth parameters and expression of genes involved in nitrogen transport and assimilatory pathways was studied in B. juncea seedlings. For this, B. juncea seedlings were treated with four combinations of C and N source viz., N source alone (-Suc+N), C source alone (+Suc-N), with N and C source (+Suc+N) or without N and C source (-Suc-N). Cotyledon size and shoot length were found to be increased in seedlings, when nitrogen alone was present in the medium. Distinct expression pattern of genes in both, root and shoot tissues was observed in response to exogenously supplied N and C. The presence or depletion of nitrogen alone in the medium leads to severe up- or down-regulation of key genes involved in N-uptake and transport (BjNRT1.1, BjNRT1.8) in root tissue and genes involved in nitrate reduction (BjNR1 and BjNR2) in shoot tissue. Moreover, expression of several genes, like BjAMT1.2, BjAMT2 and BjPK in root and two genes BjAMT2 and BjGS1.1 in shoot were found to be regulated only when C source was present in the medium. Majority of genes were found to respond in root and shoot tissues, when both C and N source were present in the medium, thus reflecting their importance as a signal in regulating expression of genes involved in N-uptake and assimilation. The present work provides insight into the regulation of genes of N-uptake and assimilatory pathway in B. juncea by interaction of both carbon and nitrogen. PMID:27637072

Syntrophic association of termite gut bacterial symbionts with bifunctional characteristics of cellulose degrading and polyhydroxyalkanoate producing bacteria.

PubMed

Cibichakravarthy, Balasubramanian; Abinaya, Subramani; Prabagaran, Solai Ramatchandirane

2017-10-01

The guild between higher termites and their partnership with the diverse community of bacteria and archaea in their gut is a marvel evolutionary achievement. Sustained attempts were made worldwide with a quest for identifying viable important biological macromolecule polyhydroxyalkanoate (PHA) accumulating bacteria. Termite gut serve as a novel source for bacteria with dual properties like PHA production as well as cellulose degradation. Among 40 isolates cultivated, 32.5% turned positive for PCR based screening of PhaC gene. The 16S rRNA gene sequencing revealed that elite PHA producer and cellulose degrader which is phylogenetically affiliated to Bacillus cereus. The PHA production was maximized by employing different carbon and nitrogen sources along with altered pH and temperatures. GC-MS, FTIR and 1 HNMR analyses confirmed the presence of PHA and the thermal characterization was performed through TGA and DSC for the termite gut isolate. Our results indicated that the combined integrative approach using isolated strains from termite gut would be preferable choice in producing biomolecules from cellulosic materials. Copyright © 2017. Published by Elsevier B.V.

Source partitioning of anthropogenic groundwater nitrogen in a mixed-use landscape, Tutuila, American Samoa

NASA Astrophysics Data System (ADS)

Shuler, Christopher K.; El-Kadi, Aly I.; Dulai, Henrietta; Glenn, Craig R.; Fackrell, Joseph

2017-12-01

This study presents a modeling framework for quantifying human impacts and for partitioning the sources of contamination related to water quality in the mixed-use landscape of a small tropical volcanic island. On Tutuila, the main island of American Samoa, production wells in the most populated region (the Tafuna-Leone Plain) produce most of the island's drinking water. However, much of this water has been deemed unsafe to drink since 2009. Tutuila has three predominant anthropogenic non-point-groundwater-pollution sources of concern: on-site disposal systems (OSDS), agricultural chemicals, and pig manure. These sources are broadly distributed throughout the landscape and are located near many drinking-water wells. Water quality analyses show a link between elevated levels of total dissolved groundwater nitrogen (TN) and areas with high non-point-source pollution density, suggesting that TN can be used as a tracer of groundwater contamination from these sources. The modeling framework used in this study integrates land-use information, hydrological data, and water quality analyses with nitrogen loading and transport models. The approach utilizes a numerical groundwater flow model, a nitrogen-loading model, and a multi-species contaminant transport model. Nitrogen from each source is modeled as an independent component in order to trace the impact from individual land-use activities. Model results are calibrated and validated with dissolved groundwater TN concentrations and inorganic δ15N values, respectively. Results indicate that OSDS contribute significantly more TN to Tutuila's aquifers than other sources, and thus should be prioritized in future water-quality management efforts.

Process for the liquefaction of solid carbonaceous materials wherein nitrogen is separated from hydrogen via ammonia synthesis

DOEpatents

Stetka, Steven S.; Nazario, Francisco N.

1982-01-01

In a process for the liquefaction of solid carbonaceous materials wherein bottoms residues are upgraded with a process wherein air is employed, the improvement wherein nitrogen buildup in the system is avoided by ammonia synthesis. In a preferred embodiment hydrogen from other portions of the liquefaction process will be combined with hydrogen produced as a result of the bottoms upgrading to increase the H.sub.2 :N.sub.2 ratio in the ammonia reactor.

Nutrient concentrations in surface water and groundwater, and nitrate source identification using stable isotope analysis, in the Barnegat Bay-Little Egg Harbor watershed, New Jersey, 2010–11

USGS Publications Warehouse

Wieben, Christine M.; Baker, Ronald J.; Nicholson, Robert S.

2013-01-01

Five streams in the Barnegat Bay-Little Egg Harbor (BB-LEH) watershed in southern New Jersey were sampled for nutrient concentrations and stable isotope composition under base-flow and stormflow conditions, and during the growing and nongrowing seasons, to help quantify and identify sources of nutrient loading. Samples were analyzed for concentrations of total nitrogen, ammonia, nitrate plus nitrite, organic nitrogen, total phosphorus, and orthophosphate, and for nitrogen and oxygen stable isotope ratios. Concentrations of total nitrogen in the five streams appear to be related to land use, such that streams in subbasins characterized by extensive urban development (and historical agricultural land use)—North Branch Metedeconk and Toms Rivers—exhibited the highest total nitrogen concentrations (0.84–1.36 milligrams per liter (mg/L) in base flow). Base-flow total nitrogen concentrations in these two streams were dominated by nitrate; nitrate concentrations decreased during storm events as a result of dilution by storm runoff. The two streams in subbasins with the least development—Cedar Creek and Westecunk Creek—exhibited the lowest total nitrogen concentrations (0.16–0.26 mg/L in base flow), with organic nitrogen as the dominant species in both base flow and stormflow. A large proportion of these subbasins lies within forested parts of the Pinelands Area, indicating the likelihood of natural inputs of organic nitrogen to the streams that increase during periods of storm runoff. Base-flow total nitrogen concentrations in Mill Creek, in a moderately developed basin, were 0.43 to 0.62 mg/L and were dominated by ammonia, likely associated with leachate from a landfill located upstream. Total phosphorus and orthophosphate were not found at detectable concentrations in most of the surface-water samples, with the exception of samples collected from the North Branch Metedeconk River, where concentrations ranged from 0.02 to 0.09 mg/L for total phosphorus and 0.008 to 0.011 mg/L for orthophosphate. Measurements of nitrogen and oxygen stable isotope ratios of nitrate in surface-water samples revealed that a mixture of multiple subsurface sources, which may include some combination of animal and septic waste, soil nitrogen, and commercial fertilizers, likely contribute to the base-flow nitrogen load. The results also indicate that atmospheric deposition is not a predominant source of nitrogen transported to the BB-LEH estuary from the watershed, although the contribution of nitrate from the atmosphere increases during stormflow. Atmospheric deposition of nitrate has a greater influence in the less developed subbasins within the BB-LEH watershed, likely because few other major sources of nitrogen (animal and septic waste, fertilizers) are present in the less developed subbasins. Atmospheric sources appear to contribute proportionally less of the overall nitrate as development increases within the BB-LEH watershed. Groundwater samples collected from five wells located within the BB-LEH watershed and screened in the unconfined Kirkwood-Cohansey aquifer system were analyzed for nutrient and stable isotope composition. Concentrations of nitrate ranged from not detected to 3.63 mg/L, with the higher concentrations occurring in the highly developed northern portion of the watershed, indicating the likelihood of anthropogenic sources of nitrogen. Isotope data for the two wells with the highest nitrate concentrations are more consistent with fertilizer sources than with animal or septic waste. Total phosphorus was not detected in any of the wells sampled, and orthophosphate was either not detected or measured at very low concentrations (0.005–0.009 mg/L) in each of the wells sampled.

Selection of effective macroalgal species and tracing nitrogen sources on the different part of Yantai coast, China indicated by macroalgal δ(15)N values.

PubMed

Wang, Yujue; Liu, Dongyan; Richard, Pierre; Di, Baoping

2016-01-15

To determine the dominant nitrogen sources and select effective macroalgal species for monitoring eutrophication along the Yantai coast, the total carbon (TOC), total nitrogen (TN) and nitrogen stable isotope ratio (δ(15)N) in macroalgal tissue were analyzed in conjunction with environmental variables in seawater along the Yantai coastline. The ranges of macroalgal tissue δ(15)N values together with dissolved inorganic nitrogen (DIN) composition indicated that except for the atmospheric deposition, there were three dominant types of nitrogen sources along the Yantai coast, with the agricultural fertilizer usage and factorial wastewater input at the S1 (Zhifu Island coast), the sewage discharge at S2 (the Moon Bay coast), the sewage discharge together with aquaculture impacts at S3 (Fisherman Wharf coast) and S4 (the Horse Island coast). Macroalgal growth were not limited by DIN but limited by P at S2, S3 and S4. Macroalgal species suitable or not for DIN source tracing along the Yantai coast were discussed. For sites with low DIN concentration, many species of three phyla could be used for DIN sources tracing with Laurencia okamurai, Gloiopeltis furcata and Ulva pertusa being ideal species. For site with high DIN concentration, however, species of Rhodophyta were not suitable and only Scytosiphon lomentaria and Monostroma nitidium were chosen. Copyright © 2015 Elsevier B.V. All rights reserved.

The nitrogen isotopic composition in soils and plants: Its use in environmental studies (A Review)

NASA Astrophysics Data System (ADS)

Makarov, M. I.

2009-12-01

The results of studying the isotopic composition of the nitrogen in soils and plants and its use for characterizing the nitrogen cycle in ecosystems, the transformation of nitrogen compounds in soils, the sources of nitrogen nutrition for plants, and the assessment of the symbiotic nitrogen fixation’s contribution to the nitrogen budget of ecosystems were considered for a wide variety of natural and agricultural ecosystems.

Nitrogen and carbon source balance determines longevity, independently of fermentative or respiratory metabolism in the yeast Saccharomyces cerevisiae.

PubMed

Santos, Júlia; Leitão-Correia, Fernanda; Sousa, Maria João; Leão, Cecília

2016-04-26

Dietary regimens have proven to delay aging and age-associated diseases in several eukaryotic model organisms but the input of nutritional balance to longevity regulation is still poorly understood. Here, we present data on the role of single carbon and nitrogen sources and their interplay in yeast longevity. Data demonstrate that ammonium, a rich nitrogen source, decreases chronological life span (CLS) of the prototrophic Saccharomyces cerevisiae strain PYCC 4072 in a concentration-dependent manner and, accordingly, that CLS can be extended through ammonium restriction, even in conditions of initial glucose abundance. We further show that CLS extension depends on initial ammonium and glucose concentrations in the growth medium, as long as other nutrients are not limiting. Glutamine, another rich nitrogen source, induced CLS shortening similarly to ammonium, but this effect was not observed with the poor nitrogen source urea. Ammonium decreased yeast CLS independently of the metabolic process activated during aging, either respiration or fermentation, and induced replication stress inhibiting a proper cell cycle arrest in G0/G1 phase. The present results shade new light on the nutritional equilibrium as a key factor on cell longevity and may contribute for the definition of interventions to promote life span and healthy aging.

Elucidation of the Metabolic Network of Helicobacter pylori J99 and Malaysian Clinical Strains by Phenotype Microarray.

PubMed

Lee, Woon Ching; Goh, Khean Lee; Loke, Mun Fai; Vadivelu, Jamuna

2017-02-01

Helicobacter pylori colonizes almost half of the human population worldwide. H. pylori strains are genetically diverse, and the specific genotypes are associated with various clinical manifestations including gastric adenocarcinoma, peptic ulcer disease (PUD), and nonulcer dyspepsia (NUD). However, our current knowledge of the H. pylori metabolism is limited. To understand the metabolic differences among H. pylori strains, we investigated four Malaysian H. pylori clinical strains, which had been previously sequenced, and a standard strain, H. pylori J99, at the phenotypic level. The phenotypes of the H. pylori strains were profiled using the Biolog Phenotype Microarray system to corroborate genomic data. We initiated the analyses by predicting carbon and nitrogen metabolic pathways from the H. pylori genomic data from the KEGG database. Biolog PM aided the validation of the prediction and provided a more intensive analysis of the H. pylori phenomes. We have identified a core set of metabolic nutrient sources that was utilized by all strains tested and another set that was differentially utilized by only the local strains. Pentose sugars are the preferred carbon nutrients utilized by H. pylori. The amino acids l-aspartic acid, d-alanine, and l-asparagine serve as both carbon and nitrogen sources in the metabolism of the bacterium. The phenotypic profile based on this study provides a better understanding on the survival of H. pylori in its natural host. Our data serve as a foundation for future challenges in correlating interstrain metabolic differences in H. pylori. © 2016 The Authors. Helicobacter Published by John Wiley & Sons Ltd.

Orchard nitrogen management: Which nitrogen source is best?

USDA-ARS?s Scientific Manuscript database

Suboptimal management of nitrogen fertility in pecan orchards leads to a loss of nutmeat yield and quality, but also a waste of natural resources and money. This article reviews several basic guiding principles useful to orchard managers when developing nitrogen management strategies, and determini...

Study of the effects of proline, phenylalanine, and urea foliar application to Tempranillo vineyards on grape amino acid content. Comparison with commercial nitrogen fertilisers.

PubMed

Garde-Cerdán, T; López, R; Portu, J; González-Arenzana, L; López-Alfaro, I; Santamaría, P

2014-11-15

The aim of this work was to study the influence of foliar application of different nitrogen sources on grape amino acid content. The nitrogen sources applied to Tempranillo grapevines were proline, phenylalanine, urea, and two commercial nitrogen fertilisers, both without and with amino acids in their formulations. All treatments were applied at veraison and one week later. Proline treatment did not affect the must nitrogen composition. However, phenylalanine and urea foliar application enhanced the plants' synthesis of most of the amino acids, producing similar effects. In addition, the spray of commercial nitrogen fertilisers over leaves also induced a rise in grape amino acid concentrations regardless of the presence or absence of amino acids in their formulation. The most effective treatments were phenylalanine and urea followed by nitrogen fertilisers. This finding is of oenological interest for improved must nitrogen composition, ensuring better fermentation kinetics and most likely enhancing wine quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhancement of biodegradation of crude petroleum-oil in contaminated water by the addition of nitrogen sources.

PubMed

Mukred, A M; Hamid, A A; Hamzah, A; Yusoff, W M Wan

2008-09-01

Addition of nitrogen sources as supplementary nutrient into MSM medium to enhance biodegradation by stimulating the growth four isolates, Acinetobacter faecalis, Staphylococcus sp., Pseudomonas putida and Neisseria elongata isolated from petroleum contaminated groundwater, wastewater aeration pond and biopond at the oil refinery Terengganu Malaysia was investigated. The organic nitrogen sources tested not only supported growth but also enhances biodegradation of 1% Tapis crude oil. All four isolates showed good growth especially when peptone was employed as the organic nitrogen compared to growth in the basal medium. Gas chromatography showed that more then 91, 93, 94 and 95% degradation of total hydrocarbon was observed after 5 days of incubation by isolates Pseudomonas putida, Neisseria elongate, Acinetobacter faecalis and Staphylococcus sp., respectively.

Plan of study to determine if the isotopic ratios [delta]15 N and [delta]18 O can reveal the sources of nitrate discharged by the Mississippi River into the Gulf of Mexico

USGS Publications Warehouse

Battaglin, William A.; Kendall, Carol; Goolsby, Donald A.; Boyer, Laurie L.

1997-01-01

Nitrate and other nutrients discharged from the Mississippi River basin are suspected of causing a zone of depleted dissolved oxygen (hypoxic zone) in the Gulf of Mexico each summer. The hypoxic zone may have an adverse effect on aquatic life and commercial fisheries. Commercial fertilizers are the dominant source of nitrogen input to the Mississippi basin. Other nitrogen sources include animal waste, fixation of atmospheric nitrogen by legumes, precipitation, domestic and industrial effluent, and the soil. The inputs of nitrogen from most of these sources to the Mississippi basin can be estimated and the outputs in surface water can be measured. However, nitrogen from each source is affected differently by physical, chemical, and biological processes that control nitrogen cycling in terrestrial and aquatic systems. Hence, the relative contributions from the various sources of nitrogen to nitrate load in the Mississippi River are unknown because the different sources may not contribute proportionally to their inputs in the basin. It may be possible to determine the relative contributions of the major sources of nitrate in river water using the stable isotopic ratios d15N and d18O of the nitrate ion. A few researchers have used the d15N and/or d18O isotope ratios to determine sources of nitrate in ground water, headwater catchments, and small rivers, but little is known about the isotopic composition of nitrate in larger rivers. The objective of this study is to measure the isotopic composition of nitrate and suspended organic matter in the Mississippi River and its major tributaries, in discharge to the Gulf of Mexico, and in streamflow from smaller watersheds that have distinct sources of nitrogen (row crops, animal wastes, and urban effluents) or are minimally impacted by man (undeveloped). Samples from seven sites on the Mississippi River and its tributaries and from 17 sites in smaller watersheds within the Mississippi River basin will be analyzed for d15N and d18O of dissolved nitrate. Suspended sediment collected from these sites will also be analyzed to determine the d15N, d13C, and d34S of the suspended organic material. Six samples will be collected at each site during the winter, spring, and summer of 1996-97. Results from these samples will be used to identify seasonal and flow-related variability in d15N and d18O ratios from each site and may also help determine the principal sources of the nitrate entering the Gulf of Mexico.

Reactive nitrogen oxides in the southeast United States national parks: source identification, origin, and process budget

NASA Astrophysics Data System (ADS)

Tong, Daniel Quansong; Kang, Daiwen; Aneja, Viney P.; Ray, John D.

2005-01-01

We present in this study both measurement-based and modeling analyses for elucidation of source attribution, influence areas, and process budget of reactive nitrogen oxides at two rural southeast United States sites (Great Smoky Mountains national park (GRSM) and Mammoth Cave national park (MACA)). Availability of nitrogen oxides is considered as the limiting factor to ozone production in these areas and the relative source contribution of reactive nitrogen oxides from point or mobile sources is important in understanding why these areas have high ozone. Using two independent observation-based techniques, multiple linear regression analysis and emission inventory analysis, we demonstrate that point sources contribute a minimum of 23% of total NOy at GRSM and 27% at MACA. The influence areas for these two sites, or origins of nitrogen oxides, are investigated using trajectory-cluster analysis. The result shows that air masses from the West and Southwest sweep over GRSM most frequently, while pollutants transported from the eastern half (i.e., East, Northeast, and Southeast) have limited influence (<10% out of all air masses) on air quality at GRSM. The processes responsible for formation and removal of reactive nitrogen oxides are investigated using a comprehensive 3-D air quality model (Multiscale Air Quality SImulation Platform (MAQSIP)). The NOy contribution associated with chemical transformations to NOz and O3, based on process budget analysis, is as follows: 32% and 84% for NOz, and 26% and 80% for O3 at GRSM and MACA, respectively. The similarity between NOz and O3 process budgets suggests a close association between nitrogen oxides and effective O3 production at these rural locations.

Effects of root-zone acidity on utilization of nitrate and ammonium in tobacco plants

NASA Technical Reports Server (NTRS)

Henry, L. T.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

1989-01-01

Tobacco (Nicotiana tabacum L., cv. 'Coker 319') plants were grown for 28 days in flowing nutrient culture containing either 1.0 mM NO3- or 1.0 mM NH4+ as the nitrogen source in a complete nutrient solution. Acidities of the solutions were controlled at pH 6.0 or 4.0 for each nitrogen source. Plants were sampled at intervals of 6 to 8 days for determination of dry matter and nitrogen accumulation. Specific rates of NO3- or NH4+ uptake (rate of uptake per unit root mass) were calculated from these data. Net photosynthetic rates per unit leaf area were measured on attached leaves by infrared gas analysis. When NO3- [correction of NO-] was the sole nitrogen source, root growth and nitrogen uptake rate were unaffected by pH of the solution, and photosynthetic activity of leaves and accumulation of dry matter and nitrogen in the whole plant were similar. When NH4+ was the nitrogen source, photosynthetic rate of leaves and accumulation of dry matter and nitrogen in the whole plant were not statistically different from NO3(-) -fed plants when acidity of the solution was controlled at pH 6.0. When acidity for NH4(+) -fed plants was increased to pH 4.0, however, specific rate of NH4+ uptake decreased by about 50% within the first 6 days of treatment. The effect of acidity on root function was associated with a decreased rate of accumulation of nitrogen in shoots that was accompanied by a rapid cessation of leaf development between days 6 and 13. The decline in leaf growth rate of NH4(+) -fed plants at pH 4.0 was followed by reductions in photosynthetic rate per unit leaf area. These responses of NH4(+) -fed plants to increased root-zone acidity are characteristic of the sequence of responses that occur during onset of nitrogen stress.

Genes of the N-Methylglutamate Pathway Are Essential for Growth of Methylobacterium extorquens DM4 with Monomethylamine

PubMed Central

Gruffaz, Christelle; Muller, Emilie E. L.; Louhichi-Jelail, Yousra; Nelli, Yella R.; Guichard, Gilles

2014-01-01

Monomethylamine (MMA, CH3NH2) can be used as a carbon and nitrogen source by many methylotrophic bacteria. Methylobacterium extorquens DM4 lacks the MMA dehydrogenase encoded by mau genes, which in M. extorquens AM1 is essential for growth on MMA. Identification and characterization of minitransposon mutants with an MMA-dependent phenotype showed that strain DM4 grows with MMA as the sole source of carbon, energy, and nitrogen by the N-methylglutamate (NMG) pathway. Independent mutations were found in a chromosomal region containing the genes gmaS, mgsABC, and mgdABCD for the three enzymes of the pathway, γ-glutamylmethylamide (GMA) synthetase, NMG synthase, and NMG dehydrogenase, respectively. Reverse transcription-PCR confirmed the operonic structure of the two divergent gene clusters mgsABC-gmaS and mgdABCD and their induction during growth with MMA. The genes mgdABCD and mgsABC were found to be essential for utilization of MMA as a carbon and nitrogen source. The gene gmaS was essential for MMA utilization as a carbon source, but residual growth of mutant DM4gmaS growing with succinate and MMA as a nitrogen source was observed. Plasmid copies of gmaS and the gmaS homolog METDI4690, which encodes a protein 39% identical to GMA synthetase, fully restored the ability of mutants DM4gmaS and DM4gmaSΔmetdi4690 to use MMA as a carbon and nitrogen source. Similarly, chemically synthesized GMA, the product of GMA synthetase, could be used as a nitrogen source for growth in the wild-type strain, as well as in DM4gmaS and DM4gmaSΔmetdi4690 mutants. The NADH:ubiquinone oxidoreductase respiratory complex component NuoG was also found to be essential for growth with MMA as a carbon source. PMID:24682302

Improved Electrochemical Performance of LiFePO4@N-Doped Carbon Nanocomposites Using Polybenzoxazine as Nitrogen and Carbon Sources.

PubMed

Wang, Ping; Zhang, Geng; Li, Zhichen; Sheng, Wangjian; Zhang, Yichi; Gu, Jiangjiang; Zheng, Xinsheng; Cao, Feifei

2016-10-03

Polybenzoxazine is used as a novel carbon and nitrogen source for coating LiFePO 4 to obtain LiFePO 4 @nitrogen-doped carbon (LFP@NC) nanocomposites. The nitrogen-doped graphene-like carbon that is in situ coated on nanometer-sized LiFePO 4 particles can effectively enhance the electrical conductivity and provide fast Li + transport paths. When used as a cathode material for lithium-ion batteries, the LFP@NC nanocomposite (88.4 wt % of LiFePO 4 ) exhibits a favorable rate performance and stable cycling performance.

Community health information sources--a survey in three disparate communities.

PubMed

Dart, Jared; Gallois, Cindy; Yellowlees, Peter

2008-02-01

To determine the current utilisation, importance, trust and future preference for contemporary sources of health information in three different socioeconomic groups. A pilot study including key informant interviews and direct observation was conducted in a low socioeconomic community. From this work a survey questionnaire was designed and implemented across three different communities. Semi-structured key informant interviews and focus groups capturing 52 respondents. Paper-based surveys were left in community organisations and local health practices in a low socioeconomic (LSE) community on the outskirts of Ipswich, Queensland, a mid-high socioeconomic (MSE) community in the western suburbs of Brisbane, and at a local university. Rank of current and preferred future sources of health information, importance and trustworthiness of health information sources. Across all three communities the local doctor was the most currently used, important, trusted and preferred future source of health information. The most striking difference between the three communities related to the current use and preferred future use of the internet. The internet was a more currently used source of health information and more important source in the university population than the LSE or MSE populations. It was also a less preferred source of future health information in the LSE population than the MSE or university populations. Importantly, currently used sources of health information did not reflect community members' preferred sources of health information. People in different socioeconomic communities obtain health information from various sources. This may reflect access issues, education and awareness of the internet as a source of health information, less health information seeking as well as a reluctance by the e-health community to address the specific needs of this group.

The simulated effects of wastewater-management actions on the hydrologic system and nitrogen-loading rates to wells and ecological receptors, Popponesset Bay Watershed, Cape Cod, Massachusetts

USGS Publications Warehouse

Walter, Donald A.

2013-01-01

The discharge of excess nitrogen into Popponesset Bay, an estuarine system on western Cape Cod, has resulted in eutrophication and the loss of eel grass habitat within the estuaries. Septic-system return flow in residential areas within the watershed is the primary source of nitrogen. Total Maximum Daily Loads (TMDLs) for nitrogen have been assigned to the six estuaries that compose the system, and local communities are in the process of implementing the TMDLs by the partial sewering, treatment, and disposal of treated wastewater at wastewater-treatment facilities (WTFs). Loads of waste-derived nitrogen from both current (1997–2001) and future sources can be estimated implicitly from parcel-scale water-use data and recharge areas delineated by a groundwater-flow model. These loads are referred to as “instantaneous” loads because it is assumed that the nitrogen from surface sources is delivered to receptors instantaneously and that there is no traveltime through the aquifer. The use of a solute-transport model to explicitly simulate the transport of mass through the aquifer from sources to receptors can improve implementation of TMDLs by (1) accounting for traveltime through the aquifer, (2) avoiding limitations associated with the estimation of loads from static recharge areas, (3) accounting more accurately for the effect of surface waters on nitrogen loads, and (4) determining the response of waste-derived nitrogen loads to potential wastewater-management actions. The load of nitrogen to Popponesset Bay on western Cape Cod, which was estimated by using current sources as input to a solute-transport model based on a steady-state flow model, is about 50 percent of the instantaneous load after about 7 years of transport (loads to estuary are equal to loads discharged from sources); this estimate is consistent with simulated advective traveltimes in the aquifer, which have a median of 5 years. Model-calculated loads originating from recharge areas reach 80 percent of the instantaneous load within 30 years; this result indicates that loads estimated from recharge areas likely are reasonable for estimating current instantaneous loads. However, recharge areas are assumed to remain static as stresses and hydrologic conditions change in response to wastewater-management actions. Sewering of the Popponesset Bay watershed would not change hydraulic gradients and recharge areas to receptors substantially; however, disposal of wastewater from treatment facilities can change hydraulic gradients and recharge areas to nearby receptors, particularly if the facilities are near the boundary of the recharge area. In these cases, nitrogen loads implicitly estimated by using current recharge areas that do not accurately represent future hydraulic stresses can differ significantly from loads estimated with recharge areas that do represent those stresses. Nitrogen loads to two estuaries in the Popponesset Bay system estimated by using recharge areas delineated for future hydrologic conditions and nitrogen sources were about 3 and 9 times higher than loads estimated by using current recharge areas; for this reason, reliance on static recharge areas can present limitations for effective TMDL implementation by means of a hypothetical, but realistic, wastewater-management action. A solute-transport model explicitly represents nitrogen transport from surface sources and does not rely on the use of recharge areas; because changes in gradients resulting from wastewater-management actions are accounted for in transport simulations, they provide more reliable predictions of future nitrogen loads. Explicitly representing the mass transport of nitrogen can better account for the mechanisms by which nitrogen enters the estuary and improve estimates of the attenuation of nitrogen concentrations in fresh surface waters. Water and associated nitrogen can enter an estuary as either direct groundwater discharge or as surface-water inflow. Two estuaries in the Popponesset Bay watershed receive surface-water inflows: Shoestring Bay receives water from the Santuit River, and the tidal reach of the Mashpee River receives water (and associated nitrogen) from the nontidal reach of the Mashpee River. Much of the water discharging into these streams passes through ponds prior to discharge. The additional attenuation of nitrogen in groundwater that has passed through a pond and discharged into a stream prior to entering an estuary is about 3 kilograms per day. Advective-transport times in the aquifer generally are small—median traveltimes are about 4.5 years—and nitrogen loads at receptors respond quickly to wastewater-management actions. The simulated decreases in nitrogen loads were 50 and 80 percent of the total decreases within 5 and 15 years, respectively, after full sewering of the watershed and within 3 and 10 years, for sequential phases of partial sewering and disposal at WTFs. The results show that solute-transport models can be used to assess the responses of nitrogen loads to wastewater-management actions, and that loads at ecological receptors (receiving waters—ponds, streams or coastal waters—that support ecosystems) will respond within a few years to those actions. The responses vary for individual receptors as functions of hydrologic setting, traveltimes in the aquifer, and the unique set of nitrogen sources representing current and future wastewater-disposal actions within recharge areas. Changes in nitrogen loads from groundwater discharge to individual estuaries range from a decrease of 90 percent to an increase of 80 percent following sequential phases of hypothetical but realistic wastewater-management actions. The ability to explicitly represent the transport of mass through the aquifer allows for the evaluation of complex responses that include the effects of surface waters, traveltimes, and complex changes in sources. Most of the simulated decreases in nitrogen loads to Shoestring Bay and the tidal portion of the Mashpee River, 79 and 69 percent, respectively, were caused by decreases in the nitrogen loads from surface-water inflow.

Spatial Scale Variability of NH3 and Impacts to interpolated Concentration Grids

EPA Science Inventory

Over the past decade, reduced nitrogen (NH3, NH4) has become an important component of atmospheric nitrogen deposition due to increases in agricultural activities and reductions in oxidized sulfur and nitrogen emissions from the power sector and mobile sources. Reduced nitrogen i...

40 CFR 415.490 - Applicability; description of the oxygen and nitrogen production subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... oxygen and nitrogen production subcategory. 415.490 Section 415.490 Protection of Environment... POINT SOURCE CATEGORY Oxygen and Nitrogen Production Subcategory § 415.490 Applicability; description of the oxygen and nitrogen production subcategory. The provisions of this subpart are applicable to...

40 CFR 415.490 - Applicability; description of the oxygen and nitrogen production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... oxygen and nitrogen production subcategory. 415.490 Section 415.490 Protection of Environment... POINT SOURCE CATEGORY Oxygen and Nitrogen Production Subcategory § 415.490 Applicability; description of the oxygen and nitrogen production subcategory. The provisions of this subpart are applicable to...

40 CFR 415.490 - Applicability; description of the oxygen and nitrogen production subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... oxygen and nitrogen production subcategory. 415.490 Section 415.490 Protection of Environment... POINT SOURCE CATEGORY Oxygen and Nitrogen Production Subcategory § 415.490 Applicability; description of the oxygen and nitrogen production subcategory. The provisions of this subpart are applicable to...

40 CFR 415.490 - Applicability; description of the oxygen and nitrogen production subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... oxygen and nitrogen production subcategory. 415.490 Section 415.490 Protection of Environment... POINT SOURCE CATEGORY Oxygen and Nitrogen Production Subcategory § 415.490 Applicability; description of the oxygen and nitrogen production subcategory. The provisions of this subpart are applicable to...

40 CFR 415.490 - Applicability; description of the oxygen and nitrogen production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... oxygen and nitrogen production subcategory. 415.490 Section 415.490 Protection of Environment... POINT SOURCE CATEGORY Oxygen and Nitrogen Production Subcategory § 415.490 Applicability; description of the oxygen and nitrogen production subcategory. The provisions of this subpart are applicable to...

Activated sludge is a potential source for production of biodegradable plastics from wastewater.

PubMed

Khardenavis, A; Guha, P K; Kumar, M S; Mudliar, S N; Chakrabarti, T

2005-05-01

Increased utilization of synthetic plastics caused severe environmental pollution due to their non-biodegradable nature. In the search for environmentally friendly materials to substitute for conventional plastics, different biodegradable plastics have been developed by microbial fermentations. However, limitations of these materials still exist due to high cost. This study aims at minimization of cost for the production of biodegradable plastics P(3HB) and minimization of environmental pollution. The waste biological sludge generated at wastewater treatment plants is used for the production of P(3HB) and wastewater is used as carbon source. Activated sludge was induced by controlling the carbon: nitrogen ratio to accumulate storage polymer. Initially polymer accumulation was studied by using different carbon and nitrogen sources. Maximum accumulation of polymer was observed with carbon source acetic acid and diammonium hydrogen phosphate (DAHP) as nitrogen source. Further studies were carried out to optimize the carbon: nitrogen ratios using acetic acid and DAHP. A maximum of 65.84% (w/w) P(3HB) production was obtained at C/N ratio of 50 within 96 hours of incubation.

Nitrogen sources affect productivity, desiccation tolerance and storage stability of Beauveria bassiana blastospores.

PubMed

Mascarin, G M; Kobori, N N; Jackson, M A; Dunlap, C A; Delalibera, Í

2018-03-01

Nitrogen is a critical element in industrial fermentation media. This study investigated the influence of various nitrogen sources on blastospore production, desiccation tolerance and storage stability using two strains of the cosmopolitan insect-pathogenic fungus Beauveria bassiana. Complex organic sources of nitrogen such as soy flour, autolysed yeast and cottonseed flour induced great numbers of blastospores after 2-3 days of fermentation, which also survived drying and remained viable (32-56% survival) after 9 months storage at 4°C, although variations were found between strains. Nitrogen availability in the form of free amino acids directly influenced blastospore production and resistance to desiccation. Increasing glucose and nitrogen concentrations up to 120 and 30 g l -1 , respectively, did not improve blastospore production but enhanced desiccation tolerance. Cell viability after drying and upon fast-rehydration was increased when ≥25 g acid-hydrolysed casein per litre was supplemented in the liquid culture medium. These findings indicate that low-cost complex nitrogen compounds are suitable to enhance yeast-like growth by B. bassiana with good desiccation tolerance and therefore support its further scale-up production as a mycoinsecticide. Nitrogen is the most expensive nutrient in liquid media composition, but this study underscores the feasibility of using low-cost nitrogen compounds composed mainly of agro-industrial by-products for rapid production of desiccation-tolerant B. bassiana blastospores by liquid culture fermentation. © 2018 The Society for Applied Microbiology.

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

PubMed

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

2012-02-01

Understanding the abiotic fixation of nitrogen and how such fixation can be a supply of prebiotic nitrogen is critical for understanding both the planetary evolution of, and the potential origin of life on, terrestrial planets. As nitrogen is a biochemically essential element, sources of biochemically accessible nitrogen, especially reduced nitrogen, are critical to prebiotic chemistry and the origin of life. Loss of atmospheric nitrogen can result in loss of the ability to sustain liquid water on a planetary surface, which would impact planetary habitability and hydrological processes that shape the surface. It is known that NO can be photochemically converted through a chain of reactions to form nitrate and nitrite, which can be subsequently reduced to ammonia. Here, we show that NO can also be directly reduced, by FeS, to ammonia. In addition to removing nitrogen from the atmosphere, this reaction is particularly important as a source of reduced nitrogen on an early terrestrial planet. By converting NO directly to ammonia in a single step, ammonia is formed with a higher product yield (~50%) than would be possible through the formation of nitrate/nitrite and subsequent conversion to ammonia. In conjunction with the reduction of NO, there is also a catalytic disproportionation at the mineral surface that converts NO to NO₂ and N₂O. The NO₂ is then converted to ammonia, while the N₂O is released back in the gas phase, which provides an abiotic source of nitrous oxide.

Mineralization of the Cyclic Nitramine Explosive Hexahydro-1,3,5-Trinitro-1,3,5-Triazine by Gordonia and Williamsia spp.

PubMed Central

Thompson, Karen T.; Crocker, Fiona H.; Fredrickson, Herbert L.

2005-01-01

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a cyclic nitroamine explosive that is a major component in many military high-explosive formulations. In this study, two aerobic bacteria that are capable of using RDX as the sole source of carbon and nitrogen to support their growth were isolated from surface soil. These bacterial strains were identified by their fatty acid profiles and 16S ribosomal gene sequences as Williamsia sp. KTR4 and Gordonia sp. KTR9. The physiology of each strain was characterized with respect to the rates of RDX degradation and [U-14C]RDX mineralization when RDX was supplied as a sole carbon and nitrogen source in the presence and absence of competing carbon and nitrogen sources. Strains KTR4 and KTR9 degraded 180 μM RDX within 72 h when RDX served as the only added carbon and nitrogen source while growing to total protein concentrations of 18.6 and 16.5 μg/ml, respectively. Mineralization of [U-14C]RDX to 14CO2 was 30% by strain KTR4 and 27% by KTR9 when RDX was the only added source of carbon and nitrogen. The addition of (NH4)2SO4 greatly inhibited KTR9's degradation of RDX but had little effect on that of KTR4. These are the first two pure bacterial cultures isolated that are able to use RDX as a sole carbon and nitrogen source. These two genera possess different physiologies with respect to RDX mineralization, and each can serve as a useful microbiological model for the study of RDX biodegradation with regard to physiology, biochemistry, and genetics. PMID:16332812

Aerobic degradation of 2,4,6-trinitrotoluene by Enterobacter cloacae PB2 and by pentaerythritol tetranitrate reductase

DOE Office of Scientific and Technical Information (OSTI.GOV)

French, C.E.; Bruce, N.C.; Nicklin, S.

1998-08-01

Enterobacter cloacae PB2 was originally isolated on the basis of its ability to utilize nitrate esters, such as pentaerythritol tetranitrate (PETN) and glycerol trinitrate, as the sole nitrogen source for growth. The enzyme responsible is an NADPH-dependent reductase designated PETN reductase. E. cloacae PB2 was found to be capable of slow aerobic growth with 2,4,6-trinitrotoluene (TNT) as the sole nitrogen source. Dinitrotoluenes were not produced and could not be used as nitrogen sources. Purified PETN reductase was found to reduce TNT to its hydride-Meisenheimer complex, which was further reduced to the dihydride-Meisenheimer complex. Purified PETN reductase and recombinant Escherichia colimore » expressing PETN reductase were able to liberate nitrogen as nitrite from TNT. The ability to remove nitrogen from TNT suggests that PB2 or recombinant organisms expressing PETN reductase may be useful for bioremediation of TNT-contaminated soil and water.« less

The Ustilago maydis Nit2 Homolog Regulates Nitrogen Utilization and Is Required for Efficient Induction of Filamentous Growth

PubMed Central

Horst, Robin J.; Zeh, Christine; Saur, Alexandra; Sonnewald, Sophia; Sonnewald, Uwe

2012-01-01

Nitrogen catabolite repression (NCR) is a regulatory strategy found in microorganisms that restricts the utilization of complex and unfavored nitrogen sources in the presence of favored nitrogen sources. In fungi, this concept has been best studied in yeasts and filamentous ascomycetes, where the GATA transcription factors Gln3p and Gat1p (in yeasts) and Nit2/AreA (in ascomycetes) constitute the main positive regulators of NCR. The reason why functional Nit2 homologs of some phytopathogenic fungi are required for full virulence in their hosts has remained elusive. We have identified the Nit2 homolog in the basidiomycetous phytopathogen Ustilago maydis and show that it is a major, but not the exclusive, positive regulator of nitrogen utilization. By transcriptome analysis of sporidia grown on artificial media devoid of favored nitrogen sources, we show that only a subset of nitrogen-responsive genes are regulated by Nit2, including the Gal4-like transcription factor Ton1 (a target of Nit2). Ustilagic acid biosynthesis is not under the control of Nit2, while nitrogen starvation-induced filamentous growth is largely dependent on functional Nit2. nit2 deletion mutants show the delayed initiation of filamentous growth on maize leaves and exhibit strongly compromised virulence, demonstrating that Nit2 is required to efficiently initiate the pathogenicity program of U. maydis. PMID:22247264

Inputs and internal cycling of nitrogen to a causeway influenced, hypersaline lake, Great Salt Lake, Utah, USA

USGS Publications Warehouse

Naftz, David L.

2017-01-01

Nitrogen inputs to Great Salt Lake (GSL), located in the western USA, were quantified relative to the resident nitrogen mass in order to better determine numeric nutrient criteria that may be considered at some point in the future. Total dissolved nitrogen inputs from four surface-water sources entering GSL were modeled during the 5-year study period (2010–2014) and ranged from 1.90 × 106 to 5.56 × 106 kg/year. The railroad causeway breach was a significant conduit for the export of dissolved nitrogen from Gilbert to Gunnison Bay, and in 2011 and 2012, net losses of total nitrogen mass from Gilbert Bay via the Causeway breach were 9.59 × 105 and 1.51 × 106 kg. Atmospheric deposition (wet + dry) was a significant source of nitrogen to Gilbert Bay, exceeding the dissolved nitrogen load contributed via the Farmington Bay causeway surface-water input by >100,000 kg during 2 years of the study. Closure of two railroad causeway culverts in 2012 and 2013 likely initiated a decreasing trend in the volume of the higher density Deep Brine Layer and associated declines in total dissolved nitrogen mass contained in this layer. The large dissolved nitrogen pool in Gilbert Bay relative to the amount of nitrogen contributed by surface-water inflow sources is consistent with the terminal nature of GSL and the predominance of internal nutrient cycling. The opening of the new railroad causeway breach in 2016 will likely facilitate more efficient bidirectional flow between Gilbert and Gunnison Bays, resulting in potentially substantial changes in nutrient pools within GSL.

Zinc Oxide-Containing Porous Boron-Carbon-Nitrogen Sheets from Glycine-Nitrate Combustion: Synthesis, Self-Cleaning, and Sunlight-Driven Photocatalytic Activity.

PubMed

Bharathidasan, T; Mandalam, Aditya; Balasubramanian, M; Dhandapani, P; Sathiyanarayanan, S; Mayavan, Sundar

2015-08-26

We developed a single-step thermal method that enables successful inclusion of ZnO components in the porous boron-carbon-nitrogen (BCN) framework to form a new class of functional hybrid. ZnO-containing BCN hybrids were prepared by treating a mixture of B2O3, glycine, and zinc nitrate at 500 °C. Glycine-nitrate decomposition along with B2O3 acts as a source for ZnO-BCN formation. The incorporation of ZnO onto BCN has extended the photoresponse of ZnO in the visible region, which makes ZnO-BCN a preferable photocatalyst relative to ZnO upon sunlight exposure. It is interesting to note that as-prepared 2D ZnO-BCN sheets dispersed in PDMS form a stable coating over aluminum alloys. The surface exhibited a water contact angle (CA) of 157.6° with 66.6 wt % ZnO-BCN in polydimethylsiloxane (PDMS) and a water droplet (7 μL) roll-off angle of <6° and also demonstrates oil fouling resistant superhydrophobicity. In brief, the present study focuses on the gram scale synthesis of a new class of sunlight-driven photocatalyst and also its application toward the development of superhydrophobic and oleophobic coating.

Cascading influence of inorganic nitrogen sources on DOM production, composition, lability and microbial community structure in the open ocean.

PubMed

Goldberg, S J; Nelson, C E; Viviani, D A; Shulse, C N; Church, M J

2017-09-01

Nitrogen frequently limits oceanic photosynthesis and the availability of inorganic nitrogen sources in the surface oceans is shifting with global change. We evaluated the potential for abrupt increases in inorganic N sources to induce cascading effects on dissolved organic matter (DOM) and microbial communities in the surface ocean. We collected water from 5 m depth in the central North Pacific and amended duplicate 20 liter polycarbonate carboys with nitrate or ammonium, tracking planktonic carbon fixation, DOM production, DOM composition and microbial community structure responses over 1 week relative to controls. Both nitrogen sources stimulated bulk phytoplankton, bacterial and DOM production and enriched Synechococcus and Flavobacteriaceae; ammonium enriched for oligotrophic Actinobacteria OM1 and Gammaproteobacteria KI89A clades while nitrate enriched Gammaproteobacteria SAR86, SAR92 and OM60 clades. DOM resulting from both N enrichments was more labile and stimulated growth of copiotrophic Gammaproteobacteria (Alteromonadaceae and Oceanospirillaceae) and Alphaproteobacteria (Rhodobacteraceae and Hyphomonadaceae) in weeklong dark incubations relative to controls. Our study illustrates how nitrogen pulses may have direct and cascading effects on DOM composition and microbial community dynamics in the open ocean. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Simazine biodegradation and community structures of ammonia-oxidizing microorganisms in bioaugmented soil: impact of ammonia and nitrate nitrogen sources.

PubMed

Wan, Rui; Yang, Yuyin; Sun, Weimin; Wang, Zhao; Xie, Shuguang

2014-02-01

The objective of the present study was to investigate the impact of ammonia and nitrate nitrogen sources on simazine biodegradation by Arthrobacter sp. strain SD1 and the community structures of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in non-agricultural soil. Soil microcosms with different treatments were constructed for herbicide biodegradation test. The relative abundance of the strain SD1 and the structures of AOA and AOB communities were assessed using quantitative PCR (q-PCR) and terminal restriction fragment length polymorphism (TRFLP), respectively. The co-existence of two inorganic nitrogen sources (ammonia and nitrate) had certain impact on simazine dissipation by the strain SD1. Bioaugmentation could induce a shift in the community structures of both AOA and AOB, but AOA were more responsive. Nitrogen application had significant impacts on AOA and AOB communities in bioaugmented soils. Moreover, in non-bioaugmented soil, the community structure of AOA, instead of AOB, could be quickly recovered after herbicide application. This study could add some new insights towards the impacts of nitrogen sources on s-triazine bioremediation and ammonia-oxidizing microorganisms in soil ecosystem.

Replacing process water and nitrogen sources with biogas slurry during cellulosic ethanol production.

PubMed

You, Yang; Wu, Bo; Yang, Yi-Wei; Wang, Yan-Wei; Liu, Song; Zhu, Qi-Li; Qin, Han; Tan, Fu-Rong; Ruan, Zhi-Yong; Ma, Ke-Dong; Dai, Li-Chun; Zhang, Min; Hu, Guo-Quan; He, Ming-Xiong

2017-01-01

Environmental issues, such as the fossil energy crisis, have resulted in increased public attention to use bioethanol as an alternative renewable energy. For ethanol production, water and nutrient consumption has become increasingly important factors being considered by the bioethanol industry as reducing the consumption of these resources would decrease the overall cost of ethanol production. Biogas slurry contains not only large amounts of wastewater, but also the nutrients required for microbial growth, e.g., nitrogen, ammonia, phosphate, and potassium. Therefore, biogas slurry is an attractive potential resource for bioethanol production that could serve as an alternative to process water and nitrogen sources. In this study, we propose a method that replaces the process water and nitrogen sources needed for cellulosic ethanol production by Zymomonas mobilis with biogas slurry. To test the efficacy of these methods, corn straw degradation following pretreatment with diluted NaOH and enzymatic hydrolysis in the absence of fresh water was evaluated. Then, ethanol fermentation using the ethanologenic bacterial strain Z. mobilis ZMT2 was conducted without supplementing with additional nitrogen sources. After pretreatment with 1.34% NaOH (w/v) diluted in 100% biogas slurry and continuous enzymatic hydrolysis for 144 h, 29.19 g/L glucose and 12.76 g/L xylose were generated from 30 g dry corn straw. The maximum ethanol concentration acquired was 13.75 g/L, which was a yield of 72.63% ethanol from the hydrolysate medium. Nearly 94.87% of the ammonia nitrogen was depleted and no nitrate nitrogen remained after ethanol fermentation. The use of biogas slurry as an alternative to process water and nitrogen sources may decrease the cost of cellulosic ethanol production by 10.0-20.0%. By combining pretreatment with NaOH diluted in biogas slurry, enzymatic hydrolysis, and ethanol fermentation, 56.3 kg of ethanol was produced by Z. mobilis ZMT-2 through fermentation of 1000 kg of dried corn straw. In this study, biogas slurry replaced process water and nitrogen sources during cellulosic ethanol production. The results suggest that biogas slurry is a potential alternative to water when pretreating corn straw and, thus, has important potential applications in cellulosic ethanol production from corn straw. This study not only provides a novel method for utilizing biogas slurry, but also demonstrates a means of reducing the overall cost of cellulosic ethanol.

Quantitative identification of riverine nitrogen from point, direct runoff and base flow sources.

PubMed

Huang, Hong; Zhang, Baifa; Lu, Jun

2014-01-01

We present a methodological example for quantifying the contributions of riverine total nitrogen (TN) from point, direct runoff and base flow sources by combining a recursive digital filter technique and statistical methods. First, we separated daily riverine flow into direct runoff and base flow using a recursive digital filter technique; then, a statistical model was established using daily simultaneous data for TN load, direct runoff rate, base flow rate, and temperature; and finally, the TN loading from direct runoff and base flow sources could be inversely estimated. As a case study, this approach was adopted to identify the TN source contributions in Changle River, eastern China. Results showed that, during 2005-2009, the total annual TN input to the river was 1,700.4±250.2 ton, and the contributions of point, direct runoff and base flow sources were 17.8±2.8%, 45.0±3.6%, and 37.2±3.9%, respectively. The innovation of the approach is that the nitrogen from direct runoff and base flow sources could be separately quantified. The approach is simple but detailed enough to take the major factors into account, providing an effective and reliable method for riverine nitrogen loading estimation and source apportionment.

Genetic Basis of Variations in Nitrogen Source Utilization in Four Wine Commercial Yeast Strains

PubMed Central

Gutiérrez, Alicia; Beltran, Gemma; Warringer, Jonas; Guillamón, Jose M.

2013-01-01

The capacity of wine yeast to utilize the nitrogen available in grape must directly correlates with the fermentation and growth rates of all wine yeast fermentation stages and is, thus, of critical importance for wine production. Here we precisely quantified the ability of low complexity nitrogen compounds to support fast, efficient and rapidly initiated growth of four commercially important wine strains. Nitrogen substrate abundance in grape must failed to correlate with the rate or the efficiency of nitrogen source utilization, but well predicted lag phase length. Thus, human domestication of yeast for grape must growth has had, at the most, a marginal impact on wine yeast growth rates and efficiencies, but may have left a surprising imprint on the time required to adjust metabolism from non growth to growth. Wine yeast nitrogen source utilization deviated from that of the lab strain experimentation, but also varied between wine strains. Each wine yeast lineage harbored nitrogen source utilization defects that were private to that strain. By a massive hemizygote analysis, we traced the genetic basis of the most glaring of these defects, near inability of the PDM wine strain to utilize methionine, as consequence of mutations in its ARO8, ADE5,7 and VBA3 alleles. We also identified candidate causative mutations in these genes. The methionine defect of PDM is potentially very interesting as the strain can, in some circumstances, overproduce foul tasting H2S, a trait which likely stems from insufficient methionine catabolization. The poor adaptation of wine yeast to the grape must nitrogen environment, and the presence of defects in each lineage, open up wine strain optimization through biotechnological endeavors. PMID:23826223

USING MUSSEL ISTOPE RATIOS TO ASSESS ANTHROPOGENIC NITROGEN INPUTS TO FRESHWATER ECOSYSTEMS

EPA Science Inventory

Stable nitrogen isotope ratios ( 15N) of freshwater mussels from a series of lakes and ponds were related to watershed land use characteristics to assess their utility in determining the source of nitrogen inputs to inland water bodies. Nitrogen isotope ratios measured in freshwa...

USING MUSSEL ISOTOPE RATIOS TO ASSESS ANTHROPOGEN NITROGEN INPUTS TO COASTAL ECOSYSTEMS

EPA Science Inventory

The stable nitrogen isotope ratio in ribbed mussel (Geukensia demissus) tissue was investigated as an indicator of the source of nitrogen inputs to coastal salt marshes. Mussels fed a diet of 15N enriched algae in the laboratory showed an increase in tissue nitrogen isotope rati...

Sensitivity analysis for the total nitrogen pollution of the Danjiangkou Reservoir based on a 3-D water quality model

NASA Astrophysics Data System (ADS)

Chen, Libin; Yang, Zhifeng; Liu, Haifei

2017-12-01

Inter-basin water transfers containing a great deal of nitrogen are great threats to human health, biodiversity, and air and water quality in the recipient area. Danjiangkou Reservoir, the source reservoir for China's South-to-North Water Diversion Middle Route Project, suffers from total nitrogen pollution and threatens the water transfer to a number of metropolises including the capital, Beijing. To locate the main source of nitrogen pollution into the reservoir, especially near the Taocha canal head, where the intake of water transfer begins, we constructed a 3-D water quality model. We then used an inflow sensitivity analysis method to analyze the significance of inflows from each tributary that may contribute to the total nitrogen pollution and affect water quality. The results indicated that the Han River was the most significant river with a sensitivity index of 0.340, followed by the Dan River with a sensitivity index of 0.089, while the Guanshan River and the Lang River were not significant, with the sensitivity indices of 0.002 and 0.001, respectively. This result implies that the concentration and amount of nitrogen inflow outweighs the geographical position of the tributary for sources of total nitrogen pollution to the Taocha canal head of the Danjiangkou Reservoir.

Biodegradation of Nitriles in Shale Oil

PubMed Central

Aislabie, Jackie; Atlas, Ronald M.

1988-01-01

Enrichment cultures were obtained, after prolonged incubation on a shale oil as the sole source of nitrogen, that selectively degraded nitriles. Capillary gas chromatographic analyses showed that the mixed microbial populations in the enrichments degraded the homologous series of aliphatic nitriles but not the aliphatic hydrocarbons, aromatic hydrocarbons, or heterocyclic-nitrogen compounds found in this oil. Time course studies showed that lighter nitriles were removed more rapidly than higher-molecular-weight nitriles. A Pseudomonas fluorescens strain isolated from an enrichment, which was able to completely utilize the individual nitriles undecyl cyanide and undecanenitrile as sole sources of carbon and nitrogen, was unable to attack stearonitrile when provided alone as the growth substrate. A P. aeruginosa strain, also isolated from one of the enrichments, used nitriles but not aliphatic or aromatic hydrocarbons when the oil was used as a sole nitrogen source. However, when the shale oil was used as the sole source of carbon, aliphatic hydrocarbons in addition to nitriles were degraded but aromatic hydrocarbons were still not attacked by this P. aeruginosa strain. PMID:16347731

Conidiation of Penicillium camemberti in submerged liquid cultures is dependent on the nitrogen source.

PubMed

Boualem, Khadidja; Labrie, Steve; Gervais, Patrick; Waché, Yves; Cavin, Jean-François

2016-02-01

To study the ability of a commercial Penicillium camemberti strain, used for Camembert type cheese ripening, to produce conidia during growth in liquid culture (LC), in media containing different sources of nitrogen as, industrially, conidia are produced by growth at the surface of a solid state culture because conidiation in stirred submerged aerobic LC is not known. In complex media containing peptic digest of meat, hyphae ends did not differentiate into phialides and conidia. Contrarily, in a synthetic media containing KNO3 as sole nitrogen source, hyphae ends differentiated into phialides producing 0.5 × 10(7) conidia/ml. Conidia produced in LC were 25 % less hydrophobic than conidia produced in solid culture, and this correlates with a seven-times-lower expression of the gene rodA encoding hydrophobin RodA in the mycelium grown in LC. Conidiation of P. camembertii is stimulated in iquid medium containing KNO3 as sole source of nitrogen and therefore opens up opportunities for using liquid medium in commercial productions.

Use of MODIS Vegetation Data in Dynamic SPARROW Modeling of Reactive Nitrogen Flux

NASA Astrophysics Data System (ADS)

Smith, R. A.; Brakebill, J.; Schwarz, G. E.; Nolin, A. W.; Shih, J.; Blomquist, J.; Alexander, R. B.; Macauley, M.

2012-12-01

SPARROW models are widely used to identify and quantify the sources of contaminants in watersheds and to predict their flux and concentration at specified locations downstream. Conventional SPARROW models are steady-state in form, and describe the average relationship between sources and stream conditions based on non-linear regression of long-term water quality monitoring data on spatially-referenced explanatory information. But many watershed management issues involve intra- and inter-annual changes in contaminant sources, hydrologic forcing, or other environmental conditions which cause a temporary imbalance between watershed inputs and outputs. Dynamic behavior of the system relating to changes in watershed storage and processing then becomes important. We describe the results of dynamic statistical calibration of a SPARROW model of total reactive nitrogen flux in the Potomac River Basin based on seasonal water quality and watershed explanatory data for 80 monitoring stations over the period 2000 to 2008. One challenge in dynamic modeling of reactive nitrogen is obtaining frequently-reported, spatially-detailed input data on the phenology of agricultural production and growth of other terrestrial vegetation. In this NASA-funded research, we use the Enhanced Vegetation Index (EVI) and gross primary productivity (GPP) data from the Terra Satellite-borne MODIS sensor to parameterize seasonal uptake and release of nitrogen. The spatial reference frame of the model is a 16,000-reach, 1:100,000-scale stream network, and the computational time step is seasonal. Precipitation and temperature data are from PRISM. The model describes transient storage and transport of nitrogen from multiple nonpoint sources including fertilized cropland, pasture, urban/suburban land, and atmospheric deposition. Removal of nitrogen from watershed storage to stream channels and to "permanent" sinks (deep groundwater and the atmosphere) occurs as parallel first-order processes. Point sources of nitrogen bypass storage and flow directly to stream channels. Model results indicate that, on average, a little more than half of the reactive nitrogen flux comes from transient storage; but in some sub-watersheds a large majority of the flux comes from stored nitrogen input to the watershed in previous seasons and years.

Immorally obtained principal increases investors' risk preference.

PubMed

Chen, Chuqian; Chen, Jiaxin; He, Guibing

2017-01-01

Capital derived from immoral sources is increasingly circulated in today's financial markets. The moral associations of capital are important, although their impact on investment remains unknown. This research aims to explore the influence of principal source morality on investors' risk preferences. Three studies were conducted in this regard. Study 1 finds that investors are more risk-seeking when their principal is earned immorally (through lying), whereas their risk preferences do not change when they invest money earned from neutral sources after engaging in immoral behavior. Study 2 reveals that guilt fully mediates the relationship between principal source morality and investors' risk preferences. Studies 3a and 3b introduce a new immoral principal source and a new manipulation method to improve external validity. Guilt is shown to the decrease the subjective value of morally flawed principal, leading to higher risk preference. The findings show the influence of morality-related features of principal on people's investment behavior and further support mental account theory. The results also predict the potential threats of "grey principal" to market stability.

Production of L-asparaginase by filamentous fungi.

PubMed

Sarquis, Maria Inez de Moura; Oliveira, Edna Maria Morais; Santos, Alberdan Silva; Costa, Gisela Lara da

2004-08-01

L-asparaginase production was investigated in the filamentous fungi Aspergillus tamarii and Aspergillus terreus. The fungi were cultivated in medium containing different nitrogen sources. A. terreus showed the highest L-asparaginase (activity) production level (58 U/L) when cultivated in a 2% proline medium. Both fungi presented the lowest level of L-asparaginase production in the presence of glutamine and urea as nitrogen sources. These results suggest that L-asparaginase production by of filamentous fungi is under nitrogen regulation.

Quantification of nitrogen in the liquid fraction and in vitro assessment of lysine bioavailability in the solid fraction of soybean meal hydrolysates.

PubMed

Luján-Rhenals, D; Morawicki, R; Shi, Z; Ricke, S C

2018-01-02

Soybean meal (SBM) is a product generated from the manufacture of soybean oil and has the potential for use as a source of fermentable sugars for ethanol production or as a protein source for animal feeds. Knowing the levels of nitrogen available from ammonium is a necessary element of the ethanolic fermentation process while identifying the levels of essential amino acids such as lysine is important in determining usage as a feed source. As such the purpose of this study was to quantify total nitrogen and ammonium in the liquid fraction of hydrolyzed SBM and to evaluate total and bioavailable lysine in the solid fraction of the hydrolyzed SBM. The effects of acid concentration, cellulase and β-glucosidase on total and ammonium nitrogen were studied with analysis indicating that higher acid concentrations increased nitrogen compounds with ammonium concentrations ranging from 0.20 to 1.24 g L -1 while enzymatic treatments did not significantly increase nitrogen levels. Total and bioavailable lysine was quantified by use of an auxotrophic gfpmut3 E.coli whole-cell bioassay organism incapable of lysine biosynthesis. Acid and enzymatic treatments were applied with lysine bioavailability increasing from a base of 82% for untreated SBM to up to 97%. Our results demonstrated that SBM has the potential to serve in ethanolic fermentation and as an optimal source essential amino acid lysine.

Seasonally-Dynamic SPARROW Modeling of Nitrogen Flux Using Earth Observation Data

NASA Astrophysics Data System (ADS)

Smith, R. A.; Schwarz, G. E.; Brakebill, J. W.; Hoos, A. B.; Moore, R. B.; Shih, J.; Nolin, A. W.; Macauley, M.; Alexander, R. B.

2013-12-01

SPARROW models are widely used to identify and quantify the sources of contaminants in watersheds and to predict their flux and concentration at specified locations downstream. Conventional SPARROW models describe the average relationship between sources and stream conditions based on long-term water quality monitoring data and spatially-referenced explanatory information. But many watershed management issues stem from intra- and inter-annual changes in contaminant sources, hydrologic forcing, or other environmental conditions which cause a temporary imbalance between inputs and stream water quality. Dynamic behavior of the system relating to changes in watershed storage and processing then becomes important. In this study, we describe dynamically calibrated SPARROW models of total nitrogen flux in three sub-regional watersheds: the Potomac River Basin, Long Island Sound drainage, and coastal South Carolina drainage. The models are based on seasonal water quality and watershed input data for a total 170 monitoring stations for the period 2001 to 2008. Frequently-reported, spatially-detailed input data on the phenology of agricultural production, terrestrial vegetation growth, and snow melt are often challenging requirements of seasonal modeling of reactive nitrogen. In this NASA-funded research, we use Enhanced Vegetation Index (EVI), gross primary production and snow/ice cover data from MODIS to parameterize seasonal uptake and release of nitrogen from vegetation and snowpack. The spatial reference frames of the models are 1:100,000-scale stream networks, and the computational time steps are 0.25-year seasons. Precipitation and temperature data are from PRISM. The model formulation accounts for storage of nitrogen from nonpoint sources including fertilized cropland, pasture, urban land, and atmospheric deposition. Model calibration is by non-linear regression. Once calibrated, model source terms based on previous season export allow for recursive dynamic simulation of stream flux: gradual increases or decreases in export occur as source supply rates and hydrologic forcing change. Based on an assumption that removal of nitrogen from watershed storage to stream channels and to 'permanent' sinks (e.g. the atmosphere and deep groundwater) occur as parallel first-order processes, the models can be used to estimate the approximate residence times of nonpoint source nitrogen in the watersheds.

Transport and Fate of Organic and Inorganic Nitrogen from Biosolids leachates

NASA Astrophysics Data System (ADS)

Ilani, Talli; Trifonov, Pavel; Arye, Gilboa

2014-05-01

The use of biosolids as a means to ameliorate soil becomes prevalent in the last few years. In agricultural fields, the application of biosolids will be followed by irrigation; resulting in excessive leaching of the dissolved fraction of the organic matter. The dissolved organic matter (DOM) is one of the major players in the chemical, physical and biological processes in soils. The DOM mainly composed of dissolved organic carbon (DOC) and lower proportions of dissolved organic nitrogen (DON) and phosphate (DOP). The DON is considered to be the primary source of mineralisable nitrogen in the soil and can be used as an estimate of the nitrogen supplying capacity of the organic matter. Most of the researches which are dealing with nitrogen fate in terrestrial environments focused on its inorganic fractions (mainly nitrate and ammonium) and their transport toward the dipper soil layers. Since DON can be the source of the inorganic nitrogen (by providing nutrients and energy to nitrifying microbes, which in turn increases the nitrogen source for plants as nitrate), knowledge about the nature of its transport characteristics in the soil is important in the case of biosolids amendment. In addition, irrigation water quality (e.g. fresh water, wastewater or desalinized water) may significantly affect the transport and fate of the various nitrogen forms. The main objective of this study is to examine the fate and co-transport of organic and inorganics nitrogen, originating from biosolids leachates in the subsoil. The effect of water quality and flow rate under saturated steady-state flow is examined by a series of flow-through soil column experiments. The established breakthrough curves of the co-transport of total nitrogen, organic nitrogen (will be calculated from the differences between the total nitrogen measurements and the inorganic nitrogen measurements), nitrate, ammonium, dissolved organic carbon and chloride is presented and discussed.

Army Stock Positioning: How Can Distribution Performance Be Improved

DTIC Science & Technology

2017-01-01

Support RAND Make a tax -deductible charitable contribution at www.rand.org/giving/contribute www.rand.org Preface The...the source- preference logic that selects the warehouse for issuing an item to a cus- tomer. Below, we describe the LMP source-preference logic and...the AMC pilot to use it to tailor how warehouses are selected to issue items to customers. AMC Pilot Implementation of LMP Source-Preference

Dendrite-free Li metal anode enabled by a 3D free-standing lithiophilic nitrogen-enriched carbon sponge

NASA Astrophysics Data System (ADS)

Hou, Guangmei; Ren, Xiaohua; Ma, Xiaoxin; Zhang, Le; Zhai, Wei; Ai, Qing; Xu, Xiaoyan; Zhang, Lin; Si, Pengchao; Feng, Jinkui; Ding, Fei; Ci, Lijie

2018-05-01

Lithium metal is considered as the ultimate anode material for high-energy Li battery systems. However, the commercial application of lithium anode is impeded by issues with safety and low coulombic efficiency induced by Li dendrite growth. Herein, a free-standing three-dimensional nitrogen-enriched graphitic carbon sponge with a high nitrogen content is proposed as a multifunctional current collect for Lithium accommodation. The abundant lithiophilic N-containing functional groups are served as preferred nucleation sites to guide a uniform Li deposition. In addition, the nitrogen-enriched graphitic carbon sponge with a high specific surface area can effectively reduce the local current density. As a result of the synergistic effect, the nitrogen-enriched graphitic carbon sponge electrode realizes a long-term stable cycling without dendrites formation. Notably, the as-obtained composite electrode can deliver an ultra-high specific capacity of ∼3175 mA h g-1. The nitrogen-enriched graphitic carbon sponge might provide innovative insights to design a superior matrix for dendrite-free Li anode.

Assessment of source-based nitrogen removal alternatives in leather tanning industry wastewater.

PubMed

Zengin, G; Olmez, T; Doğruel, S; Kabdaşli, I; Tünay, O

2002-01-01

Nitrogen is an important parameter of leather tanning wastewaters. Magnesium ammonium phosphate (MAP) precipitation is a chemical treatment alternative for ammonia removal. In this study, a detailed source-based wastewater characterisation of a bovine leather tannery was made and nitrogen speciation as well as other basic pollutant parameter values was evaluated. This evaluation has led to definition of alternatives for source-based MAP treatment. MAP precipitation experiments conducted on these alternatives have yielded over 90% ammonia removal at pH 9.5 and using stoichiometric doses. Among the alternatives tested liming-deliming and bating-washing was found to be the most advantageous providing 71% ammonia removal.

Nitrogen oxides in the troposphere - Global and regional budgets

NASA Technical Reports Server (NTRS)

Logan, J. A.

1983-01-01

The cycle of nitrogen oxides in the troposphere is discussed from both global and regional perspectives. Global sources for NO(x) are estimated to be of magnitude 50 (+ or - 25) x 10 to the 12th gm N/yr. Nitrogen oxides are derived from combustion of fossil fuels (40 percent) and biomass burning (25 percent) with the balance from lightning and microbial activity in soils. Estimates for the rate of removal of NOx based on recent atmospheric and precipitation chemistry data are consistent with global source strengths derived here. Industrial and agricultural activities provide approximately two thirds of the global source for NOx. In North America, sources from combustion of fossil fuels exceed natural sources by a factor of 3-13. Wet deposition removes about one third of the combustion source of NOx over North America, while dry deposition removes a similar amount. The balance is exported from the continent. Deposition of nitrate in precipitation over eastern Canada and the western Atlantic is clearly influenced by sources of NOx in the eastern United States.

Tracking Nonpoint Source Nitrogen and Carbon in Watersheds of Chesapeake Bay

NASA Astrophysics Data System (ADS)

Kaushal, S.; Pennino, M. J.; Duan, S.; Blomquist, J.

2012-12-01

Humans have altered nitrogen and carbon cycles in rivers regionally with important impacts on coastal ecosystems. Nonpoint source nitrogen pollution is a leading contributor to coastal eutrophication and hypoxia. Shifts in sources of carbon impact downstream ecosystem metabolism and fate and transport of contaminants in coastal zones. We used a combination of stable isotopes and optical tracers to investigate fate and transport of nitrogen and carbon sources in tributaries of the largest estuary in the U.S., the Chesapeake Bay. We analyzed isotopic composition of water samples from major tributaries including the Potomac River, Susquehanna River, Patuxent River, and Choptank River during routine and storm event sampling over multiple years. A positive correlation between δ15N-NO3- and δ18O-NO3- in the Potomac River above Washington D.C. suggested denitrification or biological uptake in the watershed was removing agriculturally-derived N during summer months. In contrast, the Patuxent River in Maryland showed elevated δ15N-NO3- (5 - 12 per mil) with no relationship to δ18O-NO3- suggesting the importance of wastewater sources. From the perspective of carbon sources, there were distinct isotopic values of the δ13C-POM of particulate organic matter and fluorescence excitation emission matrices (EEMS) for rivers influenced by their dominant watershed land use. EEMS showed that there were increases in the humic and fulvic fractions of dissolved organic matter during spring floods, particularly in the Potomac River. Stable isotopic values of δ13C-POM also showed rapid depletion suggesting terrestrial carbon "pulses" in the Potomac River each spring. The δ15N-POM peaked to 10 - 15 per mil each spring suggested a potential manure source or result of biological processing within the watershed. Overall, there were considerable changes in sources and transformations of nitrogen and carbon that varied across rivers and that contribute to nitrogen and carbon loads. Anticipating changes in sources and transformations will be critical for effectively managing nonpoint pollution and ecosystem services such as drinking water quality and coastal habitat.

Student Preferences for Different Sources of Scientific Information

ERIC Educational Resources Information Center

Fraser, Barry J.; Northfield, Jeffrey R.

1978-01-01

Uses four measures of attitude towards different sources of scientific information, namely experiments, experts, books and teachers, to investigate the relative preferences for the different sources among a sample of 7th grade students in Melbourne. Also explores relationships between student changes in attitude to these sources and a number of…

The fate of nitrogen affected by biochar and fertilizer source

USDA-ARS?s Scientific Manuscript database

Continuous improvement of nitrogen (N) use efficiency (NUE) and minimizing environmental loss is necessary to address the issues related to N fertilizer use in agronomic systems. The objective of this research was to determine the effectiveness of biochar amendment and fertilizer source on NUE impro...

Sources and Loading of Nitrogen to U.S. Estuaries

EPA Science Inventory

Previous assessments of land-based nitrogen loading and sources to U.S. estuaries have been limited to estimates for larger systems with watersheds at the scale of 8-digit HUCs and larger, in part due to the coarse resolution of available data, including estuarine watershed bound...

Nitrogen and phosphorus in streams of the Great Miami River Basin, Ohio, 1998-2000

USGS Publications Warehouse

Reutter, David C.

2003-01-01

Sources and loads of nitrogen and phosphorus in streams of the Great Miami River Basin were evaluated as part of the National Water-Quality Assessment program. Water samples were collected by the U.S. Geological Survey from October 1998 through September 2000 (water years 1999 and 2000) at five locations in Ohio on a routine schedule and additionally during selected high streamflows. Stillwater River near Union, Great Miami River near Vandalia, and Mad River near Eagle City were selected to represent predominantly agricultural areas upstream from the Dayton metropolitan area. Holes Creek near Kettering is in the Dayton metropolitan area and was selected to represent an urban area in the Great Miami River Basin. Great Miami River at Hamilton is downstream from the Dayton and Hamilton-Middletown metropolitan areas and was selected to represent mixed agricultural and urban land uses of the Great Miami River Basin. Inputs of nitrogen and phosphorus to streams from point and nonpoint sources were estimated for the three agricultural basins and for the Great Miami River Basin as a whole. Nutrient inputs from point sources were computed from the facilities that discharge one-half million gallons or more per day into streams of the Great Miami River Basin. Nonpoint-source inputs estimated in this report are atmospheric deposition and commercial-fertilizer and manure applications. Loads of ammonia, nitrate, total nitrogen, orthophosphate, and total phosphorus from the five sites were computed with the ESTIMATOR program. The computations show nitrate to be the primary component of instream nitrogen loads, and particulate phosphorus to be the primary component of instream phosphorus loads. The Mad River contributed the smallest loads of total nitrogen and total phosphorus to the study area upstream from Dayton, whereas the Upper Great Miami River (upstream from Vandalia) contributed the largest loads of total nitrogen and total phosphorus to the Great Miami River Basin upstream from Dayton. An evaluation of monthly mean loads shows that nutrient loads were highest during winter 1999 and lowest during the drought of summer and autumn 1999. During the 1999 drought, point sources were the primary contributors of nitrogen and phosphorus loads to most of the study area. Nonpoint sources, however, were the primary contributors of nitrogen and phosphorus loads during months of high streamflow. Nonpoint sources were also the primary contributors of nitrogen loads to the Mad River during the 1999 drought, owing to unusually large amounts of ground-water discharge to the stream. The Stillwater River Basin had the highest nutrient yields in the study area during months of high streamflow; however, the Mad River Basin had the highest yields of all nutrients except ammonia during the months of the 1999 drought. The high wet-weather yields in the Stillwater River Basin were caused by agricultural runoff, whereas high yields in the Mad River Basin during drought resulted from the large, sustained contribution of ground water to streamflow throughout the year. In the basins upstream from Dayton, an estimated 19 to 25 percent of the nonpoint source of nitrogen and 4 to 5 percent of the nonpoint source of phosphorus that was deposited or applied to the land was transported into streams.

Nitrogen Dioxide's Impact on Indoor Air Quality

EPA Pesticide Factsheets

The two most prevalent oxides of nitrogen are nitrogen dioxide (NO2) and nitric oxide (NO). Both are toxic gases with NO2 being a highly reactive oxidant and corrosive. The primary sources indoors are combustion processes.

Use of transcriptomics and co-expression networks to analyze the interconnections between nitrogen assimilation and photorespiratory metabolism

PubMed Central

Pérez-Delgado, Carmen M.; Moyano, Tomás C.; García-Calderón, Margarita; Canales, Javier; Gutiérrez, Rodrigo A.; Márquez, Antonio J.; Betti, Marco

2016-01-01

Nitrogen is one of the most important nutrients for plants and, in natural soils, its availability is often a major limiting factor for plant growth. Here we examine the effect of different forms of nitrogen nutrition and of photorespiration on gene expression in the model legume Lotus japonicus with the aim of identifying regulatory candidate genes co-ordinating primary nitrogen assimilation and photorespiration. The transcriptomic changes produced by the use of different nitrogen sources in leaves of L. japonicus plants combined with the transcriptomic changes produced in the same tissue by different photorespiratory conditions were examined. The results obtained provide novel information on the possible role of plastidic glutamine synthetase in the response to different nitrogen sources and in the C/N balance of L. japonicus plants. The use of gene co-expression networks establishes a clear relationship between photorespiration and primary nitrogen assimilation and identifies possible transcription factors connected to the genes of both routes. PMID:27117340

Nutrient Mass Balance for the Mobile River Basin in Alabama, Georgia, and Mississippi

NASA Astrophysics Data System (ADS)

Harned, D. A.; Harvill, J. S.; McMahon, G.

2001-12-01

The source and fate of nutrients in the Mobile River drainage basin are important water-quality concerns in Alabama, Georgia, and Mississippi. Land cover in the basin is 74 percent forested, 16 percent agricultural, 2.5 percent developed, and 4 percent wetland. A nutrient mass balance calculated for 18 watersheds in the Mobile River Basin indicates that agricultural non-point nitrogen and phosphorus sources and urban non-point nitrogen sources are the most important factors associated with nutrients in the streams. Nitrogen and phosphorus inputs from atmospheric deposition, crop fertilizer, biological nitrogen fixation, animal waste, and point sources were estimated for each of the 18 drainage basins. Total basin nitrogen inputs ranged from 27 to 93 percent from atmospheric deposition (56 percent mean), 4 to 45 percent from crop fertilizer (25 percent mean), <0.01 to 31 percent from biological nitrogen fixation (8 percent mean), 2 to 14 percent from animal waste (8 percent mean), and 0.2 to 11 percent from point sources (3 percent mean). Total basin phosphorus inputs ranged from 10 to 39 percent from atmospheric deposition (26 percent mean), 7 to 51 percent from crop fertilizer (28 percent mean), 20 to 64 percent from animal waste (41 percent mean), and 0.2 to 11 percent from point sources (3 percent mean). Nutrient outputs for the watersheds were estimated by calculating instream loads and estimating nutrient uptake, or withdrawal, by crops. The difference between the total basin inputs and outputs represents nutrients that are retained or processed within the basin while moving from the point of use to the stream, or in the stream. Nitrogen output, as a percentage of the total basin nitrogen inputs, ranged from 19 to 79 percent for instream loads (35 percent mean) and from 0.01 to 32 percent for crop harvest (10 percent mean). From 53 to 87 percent (75 percent mean) of nitrogen inputs were retained within the 18 basins. Phosphorus output ranged from 9 to 29 percent for instream loads (18 percent mean) and from 0.01 to 23 percent for crop harvest (7 percent mean). The basins retained from 60 to 87 percent (74 percent mean) of phosphorous inputs. Correlation of basin nutrient output loads and concentrations with the basin inputs and correlation of output loads and concentrations with basin land use were tested using the Spearman rank test. The correlation analysis indicated that higher nitrogen concentrations in the streams are associated with urban areas and higher loads are associated with agriculture; high phosphorus output loads and concentrations are associated with agriculture. Higher nutrient loads in agricultural basins are partly an effect of basin size-- larger basins generate larger nutrient loads. Nutrient loads and concentrations showed no significant correlation to point-source inputs. Nitrogen loads were significantly (p<0.05, correlation coefficient >0.5) higher in basins with greater cropland areas. Nitrogen concentrations also increased as residential, commercial, and total urban areas increased. Phosphorus loads were positively correlated with animal-waste inputs, pasture, and total agricultural land. Phosphorus concentrations were highest in basins with the greatest amounts of row-crop agriculture.

Age and quality of ground water and sources of nitrogen in the aquifers in Pumpkin Creek Valley, western Nebraska, 2000

USGS Publications Warehouse

Steele, G.V.; Cannia, J.C.; Sibray, S.S.; McGuire, V.L.

2005-01-01

Ground water is the source of drinking water for the residents of Pumpkin Creek Valley, western Nebraska. In this largely agricultural area, shallow aquifers potentially are susceptible to nitrate contamination. During the last 10 years, ground-water levels in the North Platte Natural Resources District have declined and contamination has become a major problem for the district. In 2000, the U.S. Geological Survey and the North Platte Natural Resources District began a cooperative study to determine the age and quality of the ground water and the sources of nitrogen in the aquifers in Pumpkin Creek Valley. Water samples were collected from 8 surface-water sites, 2 springs, and 88 ground-water sites during May, July, and August 2000. These samples were analyzed for physical properties, nutrients or nitrate, and hydrogen and oxygen isotopes. In addition, a subset of samples was analyzed for any combination of chlorofluorocarbons, tritium, tritium/helium, sulfur-hexafluoride, carbon-14, and nitrogen-15. The apparent age of ground water in the alluvial aquifer typically varied from about 1980 to modern, whereas ground water in the fractured Brule Formation had a median value in the 1970s. The Brule Formation typically contained ground water that ranged from the 1940s to the 1990s, but low-yield wells had apparent ages of 5,000 to 10,000 years before present. Data for oxygen-18 and deuterium indicated that lake-water samples showed the greatest effects from evaporation. Ground-water data showed no substantial evaporative effects and some ground water became isotopically heavier as the water moved downgradient. In addition, the physical and chemical ground-water data indicate that Pumpkin Creek is a gaining stream because little, if any, of its water is lost to the ground-water system. The water-quality type changed from a sodium calcium bicarbonate type near Pumpkin Creek's headwaters to a calcium sodium bicarbonate type near its mouth. Nitrate concentrations were largest in the alluvial system (median = 5 mg/L) and smallest in the surface-water system (median = 1 mg/L). Most nitrate concentrations exceeding the U.S. Environmental Protection Agency maximum contaminant level for drinking water of 10 mg/L as nitrogen were adjacent to irrigated fields and in areas where alluvial sediments are less than 50 ft thick. Sources of nitrogen in the ground water of the study area included naturally occurring nitrogen, commercial fertilizer, and animal waste. Based on nitrate concentration and delta nitrogen-15, the nitrogen in 65 percent of the water samples appears to have originated from a mixture of commercial fertilizers and animal waste. Some of the smallest nitrate concentrations in the ground-water samples contained some of the largest delta nitrogen-15 values (greater than 10 per mil), which suggests animal waste as the likely source. Commercial fertilizers were the likely source of most of the nitrogen in water samples with nitrate concentrations that exceeded 10 mg/L. The source of the nitrogen in water samples with nitrate concentrations exceeding 10 mg/L, but with delta nitrogen-15 values close to 10 per mil, could not be determined.

Compost and manure effects on sugarbeet nitrogen uptake, nitrogen recovery, and nitrogen use efficiency

USDA-ARS?s Scientific Manuscript database

To maximize recoverable sucrose from sugarbeet (Beta vulgaris L.), producers must effectively manage added nitrogen (N), whether it be from urea or organic sources such as manure or composted manure. Our multi-site study’s objective was to determine the effects of a one-time application of stockpil...

Effect of management on nitrogen budgets and implications for air, soil, and water quality

USDA-ARS?s Scientific Manuscript database

Nitrogen is a key nutrient for both national and global food security, and nitrogen inputs from organic and/or inorganic sources are essential to maintain sustainable and economically viable agricultural systems. The challenge with nitrogen is that it is very dynamic and mobile, and some forms are s...

The effects of nitrogen pollutants on the isotopic signal (δ15N) of Ulva lactuca: Microcosm experiments.

PubMed

Orlandi, Lucia; Calizza, Edoardo; Careddu, Giulio; Carlino, Pasquale; Costantini, Maria Letizia; Rossi, Loreto

2017-02-15

Effects of two chemical forms of Nitrogen (NH 4 + and NO 3 - ) on δ 15 N in Ulva lactuca were analysed separately and in mixture at two concentrations. We assessed whether the δ 15 N values of U. lactuca discriminate between Nitrogen from synthetic fertilisers (inorganic) and from fresh cow manure (organic), and the isotopic ability of the macroalga to reflect Nitrogen concentrations. Isotopic signature and N content of the macroalga reflected different nitrogenous sources and their concentrations after 48h. The inorganic Nitrogen source (NH 4 NO 3 ) altered the isotopic values of the macroalgae more than Nitrogen from fresh cow manure (NO 3 - ). δ 15 N values observed in the mixed solution did not differ from those displayed in NH 4 NO 3 treatment alone. We conclude that stable isotope analysis of U. lactuca collected in an unpolluted site and experimentally submerged in sites suspected of being affected by disturbance is a useful tool for rapid monitoring of anthropogenic discharges of Nitrogen pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Method for removal of nitrogen oxides from stationary combustion sources

NASA Technical Reports Server (NTRS)

Cooper, Charles D. (Inventor); Collins, Michelle M. (Inventor); Clausen, III, Christian A. (Inventor)

2004-01-01

A method for removing NO.sub.X from gas streams emanating from stationary combustion sources and manufacturing plants utilizes the injection of hydrogen peroxide into the gas stream for rapid gas-phase oxidation of NO to NO.sub.2 and water-soluble nitrogen acids HNO.sub.2 and HNO.sub.3. The nitrogen acids may be removed from the oxidized gas stream by wet scrubbing or by contact with a particulate alkaline material to form a nitrite/nitrate salt.

Quantifying atmospheric nitrogen outflow from the Front Range of Colorado

NASA Astrophysics Data System (ADS)

Neuman, J. A.; Eilerman, S. J.; Brock, C. A.; Brown, S. S.; Dube, W. P.; Herndon, S. C.; Holloway, J. S.; Nowak, J. B.; Roscioli, J. R.; Ryerson, T. B.; Sjostedt, S. J.; Thompson, C. R.; Trainer, M.; Veres, P. R.; Wild, R. J.

2015-12-01

Reactive nitrogen emitted to the atmosphere from urban, industrial, and agricultural sources can be transported and deposited far from the source regions, affecting vegetation, soils, and water of sensitive ecosystems. Mitigation of atmospheric nitrogen deposition requires emissions characterization and quantification. Ammonia (NH3), a full suite of gas-phase oxidized nitrogen compounds, and particulate matter were measured from an aircraft that flew downwind from concentrated animal feeding operations, oil and gas extraction facilities, and urban areas along the Colorado Front Range in March and April 2015, as part of the Shale Oil and Natural Gas Nexus (SONGNEX) field study. Additionally, NH3 measurements from a fully instrumented aircraft that flew over the same region in July and August 2014 as part of the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) are used to examine atmospheric nitrogen emission and transport. Cross-wind plume transects and altitude profiles were performed over the source regions and 60-240 km downwind. Plumes were transported in the boundary layer with large NH3 mixing ratios (typically 20-100 ppbv) and were tens of km wide. The NH3 in these plumes provided an atmospheric nitrogen burden greater than 0.2 kg N/ha. Nitrogen oxides and their oxidation products and particulate matter were also enhanced in the plumes, but with concentrations substantially less than NH3. With efficient transport followed by wet deposition, these plumes have the potential to provide a large nitrogen input to the neighboring Rocky Mountain National Park, where nitrogen deposition currently exceeds the ecological critical load of 1.5 kg N/ha/yr.

A mobile light source for carbon/nitrogen cameras

NASA Astrophysics Data System (ADS)

Trower, W. P.; Karev, A. I.; Melekhin, V. N.; Shvedunov, V. I.; Sobenin, N. P.

1995-05-01

The pulsed light source for carbon/nitrogen cameras developed to image concealed narcotics/explosives is described. This race-track microtron will produce 40 mA pulses of 70 MeV electrons, have minimal size and weight, and maximal ruggedness and reliability, so that it can be transported on a truck.

COUPLING BETWEEN THE COASTAL OCEAN AND YAQUINA BAY, OREGON: THE IMPORTANCE OF OCEANIC INPUTS RELATIVE TO OTHER NITROGEN SOURCES

EPA Science Inventory

Understanding of the role of oceanic input in nutrient loadings is important for understanding nutrient and phytoplankton dynamics in estuaries adjacent to coastal upwelling regions as well as determining the natural background conditions. We examined the nitrogen sources to Yaqu...

Latitudinal gradients in oceanic and watershed nitrogen sources to Pacific coast estuaries of North America

EPA Science Inventory

To assess the relative importance of terrestrial versus oceanic nutrient sources, we assembled natural abundance nitrogen stable isotope (δ15N) data for nitrate, green macroalgae, seagrass (Zostera marina) and mussels in the nearshore and in estuaries along the west coast o...

Use of Plackett-Burman design for rapid screening of nitrogen and carbon sources for the production of lipase in solid state fermentation by Yarrowia lipolytica from mustard oil cake (Brassica napus).

PubMed

Imandi, Sarat Babu; Karanam, Sita Kumari; Garapati, Hanumantha Rao

2013-01-01

Mustard oil cake (Brassica napus), the residue obtained after extraction of mustard oil from mustard oil seeds, was investigated for the production of lipase under solid state fermentation (SSF) using the marine yeast Yarrowia lipolytica NCIM 3589. Process parameters such as incubation time, biomass concentration, initial moisture content, carbon source concentration and nitrogen source concentration of the medium were optimized. Screening of ten nitrogen and five carbon sources has been accomplished with the help of Plackett-Burman design. The highest lipase activity of 57.89 units per gram of dry fermented substrate (U/gds) was observed with the substrate of mustard oil cake in four days of fermentation.

Sewage sludge as fertiliser - environmental assessment of storage and land application options.

PubMed

Willén, A; Junestedt, C; Rodhe, L; Pell, M; Jönsson, H

2017-03-01

Sewage sludge (SS) contains beneficial plant nutrients and organic matter, and therefore application of SS on agricultural land helps close nutrient loops. However, spreading operations are restricted to certain seasons and hence the SS needs to be stored. Storage and land application of SS are both potential sources of greenhouse gases and ammonia, leading to global warming, acidification and eutrophication. Covering the stored SS, treating it with urea and choosing the correct time for land application all have the potential to reduce emissions from the system. Using life cycle assessment (LCA), this study compares storage and land application options of SS in terms of global warming potential (GWP), acidification potential, eutrophication potential and primary energy use. The system with covered storage has the lowest impact of all categories. Systems with autumn application are preferable to spring application for all impact categories but, when nitrate leaching is considered, spring application is preferable in terms of eutrophication and primary energy use and, for some SS treatments, GWP. Ammonia addition reduces nitrous oxide and ammonia emissions during storage, but increases these emissions after land application. Storage duration has a large impact on GWP, while amount of chemical nitrogen fertiliser substituted has a large impact on primary energy use.

Electrode structure of a compact microwave driven capacitively coupled atomic beam source

NASA Astrophysics Data System (ADS)

Shimabukuro, Yuji; Takahashi, Hidenori; Wada, Motoi

2018-01-01

A compact magnetic field free atomic beam source was designed, assembled and tested the performance to produce hydrogen and nitrogen atoms. A forced air-cooled solid-state microwave power supply at 2.45 GHz frequency drives the source up to 100 W through a coaxial transmission cable coupled to a triple stub tuner for realizing a proper matching condition to the discharge load. The discharge structure of the source affected the range of operation pressure, and the pressure was reduced by four orders of magnitude through improving the electrode geometry to enhance the local electric field intensity. Optical emission spectra of the produced plasmas indicate production of hydrogen and nitrogen atoms, while the flux intensity of excited nitrogen atoms monitored by a surface ionization type detector showed the signal level close to a source developed for molecular beam epitaxy applications with 500 W RF power.

The impact of gas-surface reactions on mass spectrometric measurements of atomic nitrogen. [determination of atmosphere ion sources

NASA Technical Reports Server (NTRS)

Engebretson, M. J.; Mauersberger, K.

1979-01-01

The paper presents a simplified model of the ion source chemistry, explains several details of the data reduction method used in obtaining atomic-nitrogen (N) densities from OSS data, and discusses implications of gas-surface reactions for the design of future satellite-borne mass spectrometers. Because of various surface reactions, N appears in three different forms in the ion source, as N, NO, and NO2. Considering the rather small spin modulation of NO and NO2 in the semi-open ionization chamber used in the OSS instrument, it is not surprising that these reaction products have not been previously identified in closed source instruments as a measure of the presence of atomic nitrogen. Warmup and/or outgassing of the ion source are shown to drastically reduce the NO2 concentration, thereby making possible reliable measurement of ambient N densities.

Method and apparatus for coating substrates using a laser

NASA Technical Reports Server (NTRS)

Zaplatynsky, I. (Inventor)

1984-01-01

Metal substrates, preferably of titanium and titanium alloys, are coated by alloying or forming TiN on a substrate surface. A laser beam strikes the surface of a moving substrate in the presence of purified nitrogen gas. A small area of the substrate surface is quickly heated without melting. This heated area reacts with the nitrogen to form a solid solution. The alloying or formation of TiN occurs by diffusion of nitrogen into the titanium. Only the surface layer of the substrate is heated because of the high power density of the laser beam and short exposure time. The bulk of the substrate is not affected, and melting of the substrate is avoided because it would be detrimental.

Divalent Metal-Ion Complexes with Dipeptide Ligands Having Phe and His Side-Chain Anchors: Effects of Sequence, Metal Ion, and Anchor.

PubMed

Dunbar, Robert C; Berden, Giel; Martens, Jonathan K; Oomens, Jos

2015-09-24

Conformational preferences have been surveyed for divalent metal cation complexes with the dipeptide ligands AlaPhe, PheAla, GlyHis, and HisGly. Density functional theory results for a full set of complexes are presented, and previous experimental infrared spectra, supplemented by a number of newly recorded spectra obtained with infrared multiple photon dissociation spectroscopy, provide experimental verification of the preferred conformations in most cases. The overall structural features of these complexes are shown, and attention is given to comparisons involving peptide sequence, nature of the metal ion, and nature of the side-chain anchor. A regular progression is observed as a function of binding strength, whereby the weakly binding metal ions (Ba(2+) to Ca(2+)) transition from carboxylate zwitterion (ZW) binding to charge-solvated (CS) binding, while the stronger binding metal ions (Ca(2+) to Mg(2+) to Ni(2+)) transition from CS binding to metal-ion-backbone binding (Iminol) by direct metal-nitrogen bonds to the deprotonated amide nitrogens. Two new sequence-dependent reversals are found between ZW and CS binding modes, such that Ba(2+) and Ca(2+) prefer ZW binding in the GlyHis case but prefer CS binding in the HisGly case. The overall binding strength for a given metal ion is not strongly dependent on the sequence, but the histidine peptides are significantly more strongly bound (by 50-100 kJ mol(-1)) than the phenylalanine peptides.

Differential Role of Glutamate Dehydrogenase in Nitrogen Metabolism of Maize Tissues 1

PubMed Central

Loyola-Vargas, Victor Manuel; de Jimenez, Estela Sanchez

1984-01-01

Both calli and plantlets of maize (Zea mays L. var Tuxpeño 1) were exposed to specific nitrogen sources, and the aminative (NADH) and deaminative (NAD+) glutamate dehydrogenase activities were measured at various periods of time in homogenates of calli, roots, and leaves. A differential effect of the nitrogen sources on the tissues tested was observed. In callus tissue, glutamate, ammonium, and urea inhibited glutamate dehydrogenase (GDH) activity. The amination and deamination reactions also showed different ratios of activity under different nitrogen sources. In roots, ammonium and glutamine produced an increase in GDH-NADH activity whereas the same metabolites were inhibitory of this activity in leaves. These data suggest the presence of isoenzymes or conformers of GDH, specific for each tissue, whose activities vary depending on the nutritional requirements of the tissue and the state of differentiation. PMID:16663876

Sources and sinks of atmospheric N2O and the possible ozone reduction due to industrial fixed nitrogen fertilizers

NASA Technical Reports Server (NTRS)

Liu, S. C.; Cicerone, R. J.; Donahue, T. M.; Chameides, W. L.

1977-01-01

The terrestrial and marine nitrogen cycles are examined in an attempt to clarify how the atmospheric content of N2O is controlled. We review available data on the various reservoirs of fixed nitrogen, the transfer rates between the reservoirs, and estimate how the reservoir contents and transfer rates can change under man's influence. It is seen that sources, sinks and lifetime of atmospheric N2O are not understood well. Based on our limited knowledge of the stability of atmospheric N2O we conclude that future growth in the usage of industrial fixed nitrogen fertilizers could cause a 1% to 2% global ozone reduction in the next 50 years. However, centuries from now the ozone layer could be reduced by as much as 10% if soils are the major source of atmospheric N2O.

Application of the SPARROW model to assess surface-water nutrient conditions and sources in the United States Pacific Northwest

USGS Publications Warehouse

Wise, Daniel R.; Johnson, Henry M.

2013-01-01

The watershed model SPARROW (Spatially Referenced Regressions on Watershed attributes) was used to estimate mean annual surface-water nutrient conditions (total nitrogen and total phosphorus) and to identify important nutrient sources in catchments of the Pacific Northwest region of the United States for 2002. Model-estimated nutrient yields were generally higher in catchments on the wetter, western side of the Cascade Range than in catchments on the drier, eastern side. The largest source of locally generated total nitrogen stream load in most catchments was runoff from forestland, whereas the largest source of locally generated total phosphorus stream load in most catchments was either geologic material or livestock manure (primarily from grazing livestock). However, the highest total nitrogen and total phosphorus yields were predicted in the relatively small number of catchments where urban sources were the largest contributor to local stream load. Two examples are presented that show how SPARROW results can be applied to large rivers—the relative contribution of different nutrient sources to the total nitrogen load in the Willamette River and the total phosphorus load in the Snake River. The results from this study provided an understanding of the regional patterns in surface-water nutrient conditions and should be useful to researchers and water-quality managers performing local nutrient assessments.

Electrolyte salts for power sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doddapaneni, Narayan; Ingersoll, David

Electrolyte salts for power sources comprising salts of phenyl polysulfonic acids and phenyl polyphosphonic acids. The preferred salts are alkali and alkaline earth metal salts, most preferably lithium salts.

Spatiotemporal patterns and source attribution of nitrogen pollution in a typical headwater agricultural watershed in Southeastern China.

PubMed

Chen, Wenjun; He, Bin; Nover, Daniel; Duan, Weili; Luo, Chuan; Zhao, Kaiyan; Chen, Wen

2018-01-01

Excessive nitrogen (N) discharge from agriculture causes widespread problems in aquatic ecosystems. Knowledge of spatiotemporal patterns and source attribution of N pollution is critical for nutrient management programs but is poorly studied in headwaters with various small water bodies and mini-point pollution sources. Taking a typical small watershed in the low mountains of Southeastern China as an example, N pollution and source attribution were studied for a multipond system around a village using the Hydrological Simulation Program-Fortran (HSPF) model. The results exhibited distinctive spatio-seasonal variations with an overall seriousness rank for the three indicators: total nitrogen (TN) > nitrate/nitrite nitrogen (NO x - -N) > ammonia nitrogen (NH 3 -N), according to the Chinese Surface Water Quality Standard. TN pollution was severe for the entire watershed, while NO x - -N pollution was significant for ponds and ditches far from the village, and the NH 3 -N concentrations were acceptable except for the ponds near the village in summer. Although food and cash crop production accounted for the largest source of N loads, we discovered that mini-point pollution sources, including animal feeding operations, rural residential sewage, and waste, together contributed as high as 47% of the TN and NH 3 -N loads in ponds and ditches. So, apart from eco-fertilizer programs and concentrated animal feeding operations, the importance of environmental awareness building for resource management is highlighted for small farmers in headwater agricultural watersheds. As a first attempt to incorporate multipond systems into the process-based modeling of nonpoint source (NPS) pollution, this work can inform other hydro-environmental studies on scattered and small water bodies. The results are also useful to water quality improvement for entire river basins.

Health-Related Information-Seeking Behaviors and Preferences Among Mexican Patients with Cancer.

PubMed

Soto-Perez-de-Celis, Enrique; Perez-Montessoro, Viridiana; Rojo-Castillo, Patricia; Chavarri-Guerra, Yanin

2018-06-01

Understanding the preferred sources of health-related information among patients with cancer is essential for designing successful cancer education and prevention strategies. However, little is known about health-related information-seeking practices among patients living in low- and middle-income countries. We studied the preferred sources of health-related information among Mexican patients with cancer and explored which factors influence these choices. The health-related information-seeking practices among patients with cancer treated at a public hospital in Mexico City were evaluated using questions from the Spanish Version of the Health Information National Trends Survey. The characteristics of patients who sought health-related information, and of those who chose the internet as their preferred source of information, were analyzed. Fisher's exact test and logistic regression were used for statistical analyses. One hundred forty-eight patients answered the survey (median age 60 years, 70% female), of which 88 (59%) had sought for health-related information. On multivariate analysis, the only characteristic associated with lower odds of seeking health-related information was increasing age (OR 0.93, 95% CI 0.90-0.97). Sixty-one respondents (69%) listed the internet as their preferred source of health-related information. On multivariate analysis, only being of the female gender (OR 4.9, 95% CI 1.3-18.3) was related with higher odds of preferring other sources of information over the internet. Among Mexican patients with cancer, the Internet is the most widely used information source. Older age was the characteristic most strongly associated with not seeking health-related information, while being female was strongly associated with preferring other sources of information over the Internet.

The Relationships Between Alcohol Source, Autonomy in Brand Selection, and Brand Preference Among Youth in the USA

PubMed Central

Roberts, Sarah P.; Siegel, Michael B.; DeJong, William; Naimi, Timothy S.; Jernigan, David H.

2014-01-01

Aims: We aimed to describe the sources from which youth in the USA commonly obtain alcohol, their role in selecting the brands they drink and the relationship of these variables to their indicated alcohol brand preferences. Methods: We recruited 1031 underage drinkers in the age range of 13–20 through an internet panel managed by Knowledge Networks. Respondents completed an online survey assessing their recent brand-specific alcohol use, the source of their most recently consumed alcohol and whether the respondent or another person selected the brand they drank. Results: Alcohol sources were more often passive than transactional. Nearly equal proportions of youth reported that they did versus did not choose the brand of their most recent drink. Analysis revealed that the brand preferences of passive versus active source drinkers were highly similar, as were the brand preferences of respondent versus non-respondent choice drinkers. Stratification of respondents by age did not significantly change these results. Conclusion: Our findings suggest that youth are consuming a homogenous list of preferred brands regardless of the source of their most recently obtained alcohol or who selected the brand they drank. PMID:25113176

The relationships between alcohol source, autonomy in brand selection, and brand preference among youth in the USA.

PubMed

Roberts, Sarah P; Siegel, Michael B; DeJong, William; Naimi, Timothy S; Jernigan, David H

2014-01-01

We aimed to describe the sources from which youth in the USA commonly obtain alcohol, their role in selecting the brands they drink and the relationship of these variables to their indicated alcohol brand preferences. We recruited 1031 underage drinkers in the age range of 13-20 through an internet panel managed by Knowledge Networks. Respondents completed an online survey assessing their recent brand-specific alcohol use, the source of their most recently consumed alcohol and whether the respondent or another person selected the brand they drank. Alcohol sources were more often passive than transactional. Nearly equal proportions of youth reported that they did versus did not choose the brand of their most recent drink. Analysis revealed that the brand preferences of passive versus active source drinkers were highly similar, as were the brand preferences of respondent versus non-respondent choice drinkers. Stratification of respondents by age did not significantly change these results. Our findings suggest that youth are consuming a homogenous list of preferred brands regardless of the source of their most recently obtained alcohol or who selected the brand they drank. © The Author 2014. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Modeling reactive nitrogen in North America: recent ...

EPA Pesticide Factsheets

Nitrogen is an essential building block of all proteins and thus an essential nutrient for all life. The bulk of nitrogen in the environment is tightly bound as non-reactive N2. Reactive nitrogen, which is naturally produced via enzymatic reactions, forest fires and lightning, is continually recycled and cascades through air, water, and soil media (Galloway et al., 2003). Human activity has perturbed this cycle through the combustion of fossil fuels and synthesis of fertilizers. The anthropogenic contribution to this cycle is now larger than natural sources in the United States and globally (Galloway et al., 2004). Reactive nitrogen enters the biosphere primarily from emissions of oxidized nitrogen to the atmosphere from combustion sources, as inorganic fertilizer applied to crops as reduced nitrogen fixed from atmospheric N2 through the Haber-Bosch process, as organic fertilizers such as manure, and through the cultivation of nitrogen fixing crops (Canfield et al., 2010). Both the United States (US) Clean Air Act and the Canadian Environmental Protection Act (CEPA) have substantially reduced the emissions of oxidized nitrogen in North America through NOx controls on smokestacks and exhaust pipes (Sickles and Shadwick, 2015; AQA, 2015). However, reduced nitrogen emissions have remained constant during the last few decades of emission reductions. The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) c

Reversible control of biofilm formation by Cellulomonas spp. in response to nitrogen availability.

PubMed

Young, Jenna M; Leschine, Susan B; Reguera, Gemma

2012-03-01

The microbial degradation of cellulose contributes greatly to the cycling of carbon in terrestrial environments and feedbacks to the atmosphere, a process that is highly responsive to nitrogen inputs. Yet how key groups of cellulolytic microorganisms adaptively respond to the global conditions of nitrogen limitation and/or anthropogenic or climate nitrogen inputs is poorly understood. The actinobacterial genus Cellulomonas is of special interest because it incorporates the only species known to degrade cellulose aerobically and anaerobically. Furthermore, despite their inability to fix nitrogen, they are active decomposers in nitrogen-limited environments. Here we show that nitrogen limitation induced biofilm formation in Cellulomonas spp., a process that was coupled to carbon sequestration and storage in a curdlan-type biofilm matrix. The response was reversible and the curdlan matrix was solubilized and used as a carbon and energy source for biofilm dispersal once nitrogen sources became available. The biofilms attached strongly to cellulosic surfaces and, despite the growth limitation, produced cellulases and degraded cellulose more efficiently. The results show that biofilm formation is a competitive strategy for carbon and nitrogen acquisition and provide valuable insights linking nitrogen inputs to carbon sequestration and remobilization in terrestrial environments. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Yeast nitrogen utilization in the phyllosphere during plant lifespan under regulation of autophagy

PubMed Central

Shiraishi, Kosuke; Oku, Masahide; Kawaguchi, Kosuke; Uchida, Daichi; Yurimoto, Hiroya; Sakai, Yasuyoshi

2015-01-01

Recently, microbe-plant interactions at the above-ground parts have attracted great attention. Here we describe nitrogen metabolism and regulation of autophagy in the methylotrophic yeast Candida boidinii, proliferating and surviving on the leaves of Arabidopsis thaliana. After quantitative analyses of yeast growth on the leaves of A. thaliana with the wild-type and several mutant yeast strains, we showed that on young leaves, nitrate reductase (Ynr1) was necessary for yeast proliferation, and the yeast utilized nitrate as nitrogen source. On the other hand, a newly developed methylamine sensor revealed appearance of methylamine on older leaves, and methylamine metabolism was induced in C. boidinii, and Ynr1 was subjected to degradation. Biochemical and microscopic analysis of Ynr1 in vitro during a shift of nitrogen source from nitrate to methylamine revealed that Ynr1 was transported to the vacuole being the cargo for biosynthetic cytoplasm-to-vacuole targeting (Cvt) pathway, and degraded. Our results reveal changes in the nitrogen source composition for phyllospheric yeasts during plant aging, and subsequent adaptation of the yeasts to this environmental change mediated by regulation of autophagy. PMID:25900611

Biosynthesis of poly-3-hydroxybutyrate (PHB) from glycerol by Paracoccus denitrificans in a batch bioreactor: effect of process variables.

PubMed

Kalaiyezhini, D; Ramachandran, K B

2015-01-01

In this study, the kinetics of poly-3-hydroxybutyrate (PHB) biosynthesis from glycerol by Paracoccus denitrificans DSMZ 413 were explored in a batch bioreactor. Effects of inorganic and organic nitrogen source, carbon to nitrogen ratio, and other process variables such as pH, aeration, and initial glycerol concentration on PHB production were investigated in a 2.5-L bioreactor. Yeast extract was found to be the best nitrogen source compared to several organic nitrogen sources tested. At pH 6, specific growth rate, product formation rate, and accumulation of PHB within the cell were maximum. Specific growth rate increased with increase in oxygen transfer rate, but moderate oxygen transfer rate promoted PHB production. High glycerol concentration inhibited specific product formation rate but not growth. High initial carbon/nitrogen (C/N) ratio favored PHB accumulation and its productivity. At a C/N ratio of 21.4 (mol mol(-1)), 10.7 g L(-1) of PHB corresponding to 72% of cell dry weight was attained.

SOURCE ASSESSMENT: NITROGEN FERTILIZER INDUSTRY WATER EFFLUENTS

EPA Science Inventory

The report describes a study of waterborne pollutants from the manufacture of nitrogen fertilizers. It includes an evaluation of the ammonia, ammonium nitrate, urea, and nitric acid manufacturing processes. Water effluents in a nitrogen fertilizer plant originate from a variety o...

Molybdenum cofactor (chlorate-resistant) mutants of Klebsiella pneumoniae M5al can use hypoxanthine as the sole nitrogen source.

PubMed Central

Garzón, A; Li, J; Flores, A; Casadesus, J; Stewart, V

1992-01-01

Selection for chlorate resistance yields mol (formerly chl) mutants with defects in molybdenum cofactor synthesis. Complementation and genetic mapping analyses indicated that the Klebsiella pneumoniae mol genes are functionally homologous to those of Escherichia coli and occupy analogous genetic map positions. Hypoxanthine utilization in other organisms requires molybdenum cofactor as a component of xanthine dehydrogenase, and thus most chlorate-resistant mutants cannot use hypoxanthine as a sole source of nitrogen. Surprisingly, the K. pneumoniae mol mutants and the mol+ parent grew equally well with hypoxanthine as the sole nitrogen source, suggesting that K. pneumoniae has a molybdenum cofactor-independent pathway for hypoxanthine utilization. PMID:1400180

Connecting Source with Sink: The Role of Arabidopsis AAP8 in Phloem Loading of Amino Acids1[OPEN

PubMed Central

Santiago, James P.; Tegeder, Mechthild

2016-01-01

Allocation of large amounts of nitrogen to developing organs occurs in the phloem and is essential for plant growth and seed development. In Arabidopsis (Arabidopsis thaliana) and many other plant species, amino acids represent the dominant nitrogen transport forms in the phloem, and they are mainly synthesized in photosynthetically active source leaves. Following their synthesis, a broad spectrum of the amino nitrogen is actively loaded into the phloem of leaf minor veins and transported within the phloem sap to sinks such as developing leaves, fruits, or seeds. Controlled regulation of the source-to-sink transport of amino acids has long been postulated; however, the molecular mechanism of amino acid phloem loading was still unknown. In this study, Arabidopsis AMINO ACID PERMEASE8 (AAP8) was shown to be expressed in the source leaf phloem and localized to the plasma membrane, suggesting its function in phloem loading. This was further supported by transport studies with aap8 mutants fed with radiolabeled amino acids and by leaf exudate analyses. In addition, biochemical and molecular analyses revealed alterations in leaf nitrogen pools and metabolism dependent on the developmental stage of the mutants. Decreased amino acid phloem loading and partitioning to sinks led to decreased silique and seed numbers, but seed protein levels were unchanged, demonstrating the importance of AAP8 function for sink development rather than seed quality. Overall, these results show that AAP8 plays an important role in source-to-sink partitioning of nitrogen and that its function affects source leaf physiology and seed yield. PMID:27016446

Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

PubMed Central

Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

2016-01-01

Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12–15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

40 CFR 52.770 - Identification of plan.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 11/30/2004, 69 FR 69531. Article 10. Nitrogen Oxides Rules 10-1 Nitrogen Oxides Control in Clark and Floyd Counties 6/12/1996 6/3/1997, 62 FR 30253. 10-3 Nitrogen Oxide Reduction Program for Specific Source Categories 02/25/2007 11/29/2010, 75 FR 72956 Sec. 1. 10-4 Nitrogen Oxides Budget Trading Program...

Land Application of Wastes: An Educational Program. Nitrogen Considerations - Module 15, Objectives, Script and Booklet.

ERIC Educational Resources Information Center

Clarkson, W. W.; And Others

This module expands on the introductory discussion of nitrogen in other modules. The various chemical forms of nitrogen found in land treatment systems are defined. Inputs from waste application as well as natural sources are quantified for typical situations. A discussion of nitrogen transformations in the soil includes mineralization and…

Nitrogen attenuation of terrestrial carbon cycle response to global environmental factors

Treesearch

Atul Jain; Xiaojuan Yang; Haroon Kheshgi; A. David McGuire; Wilfred Post; David Kicklighter

2009-01-01

Nitrogen cycle dynamics have the capacity to attenuate the magnitude of global terrestrial carbon sinks and sources driven by CO2 fertilization and changes in climate. In this study, two versions of the terrestrial carbon and nitrogen cycle components of the Integrated Science Assessment Model (ISAM) are used to evaluate how variation in nitrogen...

Knowledge of epilepsy and preferred sources of information among elementary school teachers.

PubMed

Mott, Jared; Shellhaas, Renée A; Joshi, Sucheta M

2013-06-01

We conducted an online survey of elementary school teachers in Washtenaw County, Michigan, regarding their confidence in their knowledge of epilepsy and their preferred media or sources of information about epilepsy. Eighty-three teachers (9.3%) responded. One quarter expressed a lack of confidence in their ability to teach students with epilepsy or to respond appropriately to a seizure. Teachers most frequently (68%) cited the Internet as their primary source of information about epilepsy, with the school nurse and parents/guardians also frequently mentioned (55% and 48%, respectively). In contrast, most respondents prefer that their information come from the school nurse (74%) or a physician (73%), while only 25% cited the Internet as a preferred source. Teachers most frequently indicated EpilepsyFoundation.org (70.5%) as a trusted source of information. Future collaborative education efforts between school nurses and physicians, especially through use of the Internet, could improve teachers' knowledge of epilepsy.

Immorally obtained principal increases investors’ risk preference

PubMed Central

Chen, Jiaxin; He, Guibing

2017-01-01

Capital derived from immoral sources is increasingly circulated in today’s financial markets. The moral associations of capital are important, although their impact on investment remains unknown. This research aims to explore the influence of principal source morality on investors’ risk preferences. Three studies were conducted in this regard. Study 1 finds that investors are more risk-seeking when their principal is earned immorally (through lying), whereas their risk preferences do not change when they invest money earned from neutral sources after engaging in immoral behavior. Study 2 reveals that guilt fully mediates the relationship between principal source morality and investors’ risk preferences. Studies 3a and 3b introduce a new immoral principal source and a new manipulation method to improve external validity. Guilt is shown to the decrease the subjective value of morally flawed principal, leading to higher risk preference. The findings show the influence of morality-related features of principal on people’s investment behavior and further support mental account theory. The results also predict the potential threats of “grey principal” to market stability. PMID:28369117

External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magnien, R.E.; Summers, R.M.; Sellner, K.G.

1992-12-01

External nutrient loadings, internal nutrient pools, and phytoplankton production were examined for three major subsystems of the Chesapeake Bay Estuary-the upper Mainstem, the Patuxent Estuary, and the Potomac Estuary-during 1985-1989. The atomic nitrogen to phosphorus ratios (TN:TP) of total loads were 51, 29 and 35, respectively. Most of these loads entered at the head of the estuaries from riverine sources and major wastewater treatment plants. Seven-16% of the nitrogen load entered the head of each estuary as particulate matter in contrast to 48-69% for phosphorus. The difference seems to favor a greater loss of phosphorus than nitrogen through sedimentation andmore » burial. A major storm event in the Potomac watershed greatly increased the particulate fraction of nitrogen and phosphorus and lowered the TN:TP in the river-borne loads and accounted for 11% of the nitrogen and 31% of the phosphorus delivered to the estuary by the Potomac River during the entire 60- month period examined here. Within the Mainstem estuary, salinity dilution plots revealed strong net sources of ammonium and phosphate in the oligohaline to upper mesohaline region. indicating considerable internal recycling of nutrients to surface waters. A net sink of nitrate was indicated during summer. Phytoplankton biomass in the mesohaline Mainstem reached a peak in spring and was relatively constant throughout the other seasons. In the Patuxent and Potomac, the TN:TP ratios of external loads are 2-4 times higher than those observed over the previous two decades. These changes are attributed to point-source phosphorus controls and the likelihood that nitrogen-rich nonpoint source inputs, including contributions from the atmosphere, have increased. These higher N:P ratios now suggest a greater overall potential for phosphorus-limitation rather than nitrogen-limitation of phytoplankton in the areas studied. 66 refs., 6 figs., 7 tabs.« less

Application of low-cost algal nitrogen source feeding in fuel ethanol production using high gravity sweet potato medium.

PubMed

Shen, Yu; Guo, Jin-Song; Chen, You-Peng; Zhang, Hai-Dong; Zheng, Xu-Xu; Zhang, Xian-Ming; Bai, Feng-Wu

2012-08-31

Protein-rich bloom algae biomass was employed as nitrogen source in fuel ethanol fermentation using high gravity sweet potato medium containing 210.0 g l(-1) glucose. In batch mode, the fermentation could not accomplish even in 120 h without any feeding of nitrogen source. While, the feeding of acid-hydrolyzed bloom algae powder (AHBAP) notably promoted fermentation process but untreated bloom algae powder (UBAP) was less effective than AHBAP. The fermentation times were reduced to 96, 72, and 72 h if 5.0, 10.0, and 20.0 g l(-1) AHBAP were added into medium, respectively, and the ethanol yields and productivities increased with increasing amount of feeding AHBAP. The continuous fermentations were performed in a three-stage reactor system. Final concentrations of ethanol up to 103.2 and 104.3 g l(-1) with 4.4 and 5.3 g l(-1) residual glucose were obtained using the previously mentioned medium feeding with 20.0 and 30.0 g l(-1) AHBAP, at dilution rate of 0.02 h(-1). Notably, only 78.5 g l(-1) ethanol and 41.6 g l(-1) residual glucose were obtained in the comparative test without any nitrogen source feeding. Amino acids analysis showed that approximately 67% of the protein in the algal biomass was hydrolyzed and released into the medium, serving as the available nitrogen nutrition for yeast growth and metabolism. Both batch and continuous fermentations showed similar fermentation parameters when 20.0 and 30.0 g l(-1) AHBAP were fed, indicating that the level of available nitrogen in the medium should be limited, and an algal nitrogen source feeding amount higher than 20.0 g l(-1) did not further improve the fermentation performance. Copyright © 2012 Elsevier B.V. All rights reserved.

Growth of 1.5 micron gallium indium nitrogen arsenic antimonide vertical cavity surface emitting lasers by molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Wistey, Mark Allan

Fiber optics has revolutionized long distance communication and long haul networks, allowing unimaginable data speeds and noise-free telephone calls around the world for mere pennies per hour at the trunk level. But the high speeds of optical fiber generally do not extend to individual workstations or to the home, in large part because it has been difficult and expensive to produce lasers which emitted light at wavelengths which could take advantage of optical fiber. One of the most promising solutions to this problem is the development of a new class of semiconductors known as dilute nitrides. Dilute nitrides such as GaInNAs can be grown directly on gallium arsenide, which allows well-established processing techniques. More important, gallium arsenide allows the growth of vertical-cavity surface-emitting lasers (VCSELs), which can be grown in dense, 2D arrays on each wafer, providing tremendous economies of scale for manufacturing, testing, and packaging. Unfortunately, GaInNAs lasers have suffered from what has been dubbed the "nitrogen penalty," with high thresholds and low efficiency as the fraction of nitrogen in the semiconductor was increased. This thesis describes the steps taken to identify and essentially eliminate the nitrogen penalty. Protecting the wafer surface from plasma ignition, using an arsenic cap, greatly improved material quality. Using a Langmuir probe, we further found that the nitrogen plasma source produced a large number of ions which damaged the wafer during growth. The ions were dramatically reduced using deflection plates. Low voltage deflection plates were found to be preferable to high voltages, and simulations showed low voltages to be adequate for ion removal. The long wavelengths from dilute nitrides can be partly explained by wafer damage during growth. As a result of these studies, we demonstrated the first CW, room temperature lasers at wavelengths beyond 1.5mum on gallium arsenide, and the first GaInNAs(Sb) VCSELs beyond 1.31mum: 1.46mum. These techniques offer the promise of inexpensive, high speed fiber networking.

Growth of Chlorella vulgaris and nutrient removal in the wastewater in response to intermittent carbon dioxide.

PubMed

Liu, Xiaoning; Ying, Kezhen; Chen, Guangyao; Zhou, Canwei; Zhang, Wen; Zhang, Xihui; Cai, Zhonghua; Holmes, Thomas; Tao, Yi

2017-11-01

In this study, Chlorella vulgaris (C. vulgaris) were cultured in cell culture flask supplied with intermittent CO 2 enriched gas. The impact of CO 2 concentration (from 1% to 20% v/v) on the growth of C. vulgaris cultured in domestic wastewater was exploited in various perspectives which include biomass, specific growth rate, culture pH, carbon consumption, and the removal of nitrogen and phosphorus compounds. The results showed that the maximum microalgal biomass concentration, 1.12 g L -1 , was achieved with 10% CO 2 as a feed gas. At 20% CO 2 the growth of C. vulgaris suffered from inhibition during initial 1.5 d, but acclimated to low pH (6.3 in average) with relatively higher specific growth rate (0.3-0.5 d -1 ) during subsequent culture period. After the rapid consumption of ammonium in the wastewater, an obvious decline in the nitrate concentration was observed, indicating that C. vulgaris prefer ammonium as a primary nitrogen source. The total nitrogen and phosphorus decreased from 44.0 mg L -1 to 2.1-5.4 mg L -1 and from 5.2 mg L -1 to 0-0.6 mg L -1 within 6.5 d under the aeration of 1-20% CO 2 , respectively, but no significant difference in consumed nitrogen versus phosphorus ratio was observed among different CO 2 concentration. The kinetics of nutrients removal were also determined through the application of pseudo first order kinetic model. 5-10% CO 2 aeration was optimal for the growth of C. vulgaris in the domestic wastewater, based on the coupling of carbon consumption, microalgal biomass, the nutrients removal and kinetics constants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nonprotein nitrogen is absorbed from the large intestine and increases nitrogen balance in growing pigs fed a valine-limiting diet.

PubMed

Columbus, Daniel A; Lapierre, Hélène; Htoo, John K; de Lange, Cornelis F M

2014-05-01

Nitrogen absorption from the large intestine, largely as ammonia and possibly as amino acids (AAs), is generally thought to be of little nutritional value to nonruminant animals and humans. Ammonia-nitrogen absorbed from the large intestine, however, may be recycled into the small intestine as urea and incorporated into microbial AAs, which may then be used by the host. A cecal infusion study was performed to determine the form in which nitrogen is absorbed from the large intestine and the impact of large intestine nitrogen supply on nitrogen balance in growing pigs. Eighteen cecally cannulated barrows (initial body weight: 22.4 ± 1.2 kg) were used to determine the effect of supplying nitrogen into the large intestine from either casein or urea on whole-body nitrogen retention and urea kinetics. Treatments were cecal infusions of saline (control), casein, or urea with nitrogen infused at a rate of 40% of nitrogen intake. In a subsample of 9 pigs, (15)N(15)N-urea was infused via i.v. during the nitrogen-balance period to determine urea kinetics. All pigs were fed a valine-limiting cornstarch-soybean meal-based diet. More than 80% of infused nitrogen was apparently absorbed. Urea flux and urinary nitrogen excretion increased (P ≤ 0.05) by the same amount for both nitrogen sources, but this increase did not fully account for the increase in nitrogen absorption from the large intestine. Whole-body nitrogen retention improved with nitrogen infusions (129 vs. 114 g/d; P < 0.01) and did not differ (P > 0.05) between nitrogen sources. Absorption of nitrogen from the large intestine appears to be in the form of nonprotein nitrogen, which appears to be returned to the small intestine via urea and used there for microbial AA production and should therefore be considered when determining nitrogen and AA supply and requirements.

SOURCES AND TRANSFORMATIONS OF NITROGEN, CARBON, AND PHOSPHORUS IN THE POTOMAC RIVER ESTUARY

NASA Astrophysics Data System (ADS)

Pennino, M. J.; Kaushal, S.

2009-12-01

Global transport of nitrogen (N), carbon (C), and phosphorus (P) in river ecosystems has been dramatically altered due to urbanization. We examined the capacity of a major tributary of the Chesapeake Bay, the Potomac River, to transform carbon, nitrogen, and phosphorus inputs from the world’s largest advanced wastewater treatment facility (Washington D.C. Water and Sewer Authority). Surface water and effluent samples were collected along longitudinal transects of the Potomac River seasonally and compared to long-term interannual records of carbon, nitrogen, and phosphorus. Water samples from seasonal longitudinal transects were analyzed for dissolved organic and inorganic nitrogen and phosphorus, total organic carbon, and particulate carbon, nitrogen, and phosphorus. The source and quality of organic matter was characterized using fluorescence spectroscopy, excitation emission matrices (EEMs), and PARAFAC modeling. Sources of nitrate were tracked using stable isotopes of nitrogen and oxygen. Along the river network stoichiometric ratios of C, N, and P were determined across sites and related to changes in flow conditions. Land use data and historical water chemistry data were also compared to assess the relative importance of non-point sources from land-use change versus point-sources of carbon, nitrogen, and phosphorus. Preliminary data from EEMs suggested that more humic-like organic matter was important above the wastewater treatment plant, but more protein-like organic matter was present below the treatment plant. Levels of nitrate and ammonia showed increases within the vicinity of the wastewater treatment outfall, but decreased rapidly downstream, potentially indicating nutrient uptake and/or denitrification. Phosphate levels decreased gradually along the river with a small increase near the wastewater treatment plant and a larger increase and decrease further downstream near the high salinity zone. Total organic carbon levels show a small decrease downstream. Ecological stoichiometric ratios along the river indicate increases in C/N ratios downstream, but no corresponding trend with C/P ratios. The N/P ratios increased directly below the treatment plant and then decreased gradually downstream. The C/N/P ratios remained level until the last two sampling stations within 20 miles of the Chesapeake Bay, where there is a large increase. Despite large inputs, there may be large variations in sources and ecological stoichiometry along rivers and estuaries, and knowledge of these transformations will be important in predicting changes in the amounts, forms, and stoichiometry of nutrient loads to coastal waters.

Stable Isotope Identification of Nitrogen Sources for United States (U.S.) Pacific Coast Estuaries

EPA Science Inventory

We used natural abundance stable isotope data to evaluate nitrogen sources to U.S. west coast estuaries. We collected δ15N of macroalgae data and supplemented this with available data from the literature for estuaries from Mexico to Alaska. Stable isotope ratios of green m...

Enhanced efficiency fertilizer’s effect on cotton yield and greenhouse gas emissions

USDA-ARS?s Scientific Manuscript database

Interest in the use of enhanced-efficiency nitrogen fertilizer (EENFs) sources has increased in recent years due to the potential of these new EENF sources to increase crop yield, while at the same time decreasing N loss from agricultural fields. Nitrogen is the most essential nutrient needed to op...

EFFECTS OF AMMONIUM AND NITRATE ON NUTRIENT UPTAKE AND ACTIVITY OF NITROGEN ASSIMILATING ENZYMES IN WESTERN HEMLOCK

EPA Science Inventory

Western hemlock seedlings were grown in nutrient solutions with ammonium, nitrate or ammonium plus nitrate as nitrogen sources. he objectives were to examine (1) possible selectivity for ammonium or nitrate as an N source, (2) the maintenance of charge balance during ammonium and...

NITROGEN CONCENTRATIONS IN LOADING SOURCES FOR THREE COASTAL LAGOONS FROM ATMOSPHERIC AND WATERSHED SOURCES, ADJACENT COASTAL MARSHES, TIDAL EXCHANGES

EPA Science Inventory

Abstract and Oral Presentation Gulf Estuarine Research Society.

Standing stocks and inputs of total dissolved nitrogen (TDN) to three coastal lagoons, hereafter referred to as Kee's Bayou, Gongora, and State Park, with varying adjacent land-use, geomorphology, and water re...

Using Stable Isotopes to Assess Connectivity: the Importance of Oceanic and Watershed Nitrogen Sources for Estuarine Primary Producers

EPA Science Inventory

Estuaries located at the interface of terrestrial and oceanic ecosystems receive nutrients from both ecosystems. Stable isotopes of primary producers and consumers are often used as an indicator of nutrient sources. We assembled natural abundance nitrogen stable isotope (δ15N) d...

21 CFR 573.140 - Ammoniated cottonseed meal.

Code of Federal Regulations, 2011 CFR

2011-04-01

... required by the act, the following: (1) The name of the additive. (2) The maximum percentage of equivalent crude protein from the nonprotein nitrogen. (3) Directions for use to provide not more than 20 percent... source of protein and/or as a source of nonprotein nitrogen in an amount not to exceed 20 percent of the...

21 CFR 573.140 - Ammoniated cottonseed meal.

Code of Federal Regulations, 2012 CFR

2012-04-01

... required by the act, the following: (1) The name of the additive. (2) The maximum percentage of equivalent crude protein from the nonprotein nitrogen. (3) Directions for use to provide not more than 20 percent... source of protein and/or as a source of nonprotein nitrogen in an amount not to exceed 20 percent of the...

21 CFR 573.140 - Ammoniated cottonseed meal.

Code of Federal Regulations, 2010 CFR

2010-04-01

... required by the act, the following: (1) The name of the additive. (2) The maximum percentage of equivalent crude protein from the nonprotein nitrogen. (3) Directions for use to provide not more than 20 percent... source of protein and/or as a source of nonprotein nitrogen in an amount not to exceed 20 percent of the...

21 CFR 573.140 - Ammoniated cottonseed meal.

Code of Federal Regulations, 2013 CFR

2013-04-01

... required by the act, the following: (1) The name of the additive. (2) The maximum percentage of equivalent crude protein from the nonprotein nitrogen. (3) Directions for use to provide not more than 20 percent... source of protein and/or as a source of nonprotein nitrogen in an amount not to exceed 20 percent of the...

21 CFR 573.140 - Ammoniated cottonseed meal.

Code of Federal Regulations, 2014 CFR

2014-04-01

... required by the act, the following: (1) The name of the additive. (2) The maximum percentage of equivalent crude protein from the nonprotein nitrogen. (3) Directions for use to provide not more than 20 percent... source of protein and/or as a source of nonprotein nitrogen in an amount not to exceed 20 percent of the...

Differences among practitioners in patterns of preference for information sources in the adoption of new drugs.

PubMed

Peay, M Y; Peay, E R

1984-01-01

The major aim of this study was to identify coherent patterns in doctors' preferences for potential sources of information about new drugs and the characteristics of the doctors who display them. One hundred twenty-four general practitioners and specialists evaluated and reported their use of a number of potential sources. Overall, commercial sources were cited more often than professional ones for providing first information about a new drug, but the reverse was the case when the doctor was actively considering prescribing it. The primary professional sources received more favourable evaluation than any of the commercial sources, but results suggest that usage does not necessarily follow the doctor's opinion of a source. Relationships between reported use and evaluation reveal two coherent patterns of source preference: 'journal' and 'commercial'. The commercial pattern is particularly sharply defined, identifying a subset of doctors who can be designated justifiably as 'commercially-oriented'. Evaluation and use of particular sources varied with age and differed between specialists and general practitioners. Results indicate that differences in patterns of preference are systematically related to characteristics of the doctor in combination with the stage of the adoption process.

The effects of rising atmospheric carbon dioxide on shoot-root nitrogen and water signaling.

PubMed

Easlon, Hsien Ming; Bloom, Arnold J

2013-01-01

Terrestrial higher plants are composed of roots and shoots, distinct organs that conduct complementary functions in dissimilar environments. For example, roots are responsible for acquiring water and nutrients such as inorganic nitrogen from the soil, yet shoots consume the majority of these resources. The success of such a relationship depends on excellent root-shoot communications. Increased net photosynthesis and decreased shoot nitrogen and water use at elevated CO2 fundamentally alter these source-sink relations. Lower than predicted productivity gains at elevated CO2 under nitrogen or water stress may indicate shoot-root signaling lacks plasticity to respond to rising atmospheric CO2 concentrations. The following presents recent research results on shoot-root nitrogen and water signaling, emphasizing the influence that rising atmospheric carbon dioxide levels are having on these source-sink interactions.

PHOTOCHEMICAL MINERALIZATION OF DISSOLVED ORGANIC NITROGEN TO AMMONIUM IN THE BALTIC SEA

EPA Science Inventory

Solar radiation-induced photochemistry can be considered as a new source of nutrients when photochemical reactions release bioavailable nitrogen from biologically non-reactive dissolved organic nitrogen (DON). Pretreatments of Baltic Sea waters in the dark indicated that >72% of ...

EBP2R - an innovative enhanced biological nutrient recovery activated sludge system to produce growth medium for green microalgae cultivation.

PubMed

Valverde-Pérez, Borja; Ramin, Elham; Smets, Barth F; Plósz, Benedek Gy

2015-01-01

Current research considers wastewater as a source of energy, nutrients and water and not just a source of pollution. So far, mainly energy intensive physical and chemical unit processes have been developed to recover some of these resources, and less energy and resource demanding alternatives are needed. Here, we present a modified enhanced biological phosphorus removal and recovery system (referred to as EBP2R) that can produce optimal culture media for downstream micro-algal growth in terms of N and P content. Phosphorus is recovered as a P-stream by diversion of some of the effluent from the upstream anaerobic reactor. By operating the process at comparably low solids retention times (SRT), the nitrogen content of wastewater is retained as free and saline ammonia, the preferred form of nitrogen for most micro-algae. Scenario simulations were carried out to assess the capacity of the EBP2R system to produce nutrient rich organic-carbon depleted algal cultivation media of target composition. Via SRT control, the quality of the constructed cultivation media can be optimized to support a wide range of green micro-algal growth requirements. Up to 75% of the influent phosphorus can be recovered, by diverting 30% of the influent flow as a P-stream at an SRT of 5 days. Through global sensitivity analysis we find that the effluent N-to-P ratio and the P recovered are mainly dependent on the influent quality rather than on biokinetics or stoichiometry. Further research is needed to demonstrate that the system performance predicted through the model-based design can be achieved in reality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fish mucus versus parasitic gnathiid isopods as sources of energy and sunscreens for a cleaner fish

NASA Astrophysics Data System (ADS)

Eckes, Maxi; Dove, Sophie; Siebeck, Ulrike E.; Grutter, Alexandra S.

2015-09-01

The cleaning behaviour of the bluestreak cleaner wrasse Labroides dimidiatus is extensively used as a model system for understanding cooperation. It feeds mainly on blood-sucking gnathiid isopods and also on the epidermal mucus of client fish; the nutritional quality of these foods, however, is unknown. The epidermal mucus of reef fish contains ultraviolet (UV)-absorbing compounds (mycosporine-like amino acids, MAAs), which are only obtained via the diet; nevertheless, while La. dimidiatus has high amounts of MAAs in its mucus, their source is unknown. Therefore, the energetic value (calories and protein estimated using carbon and nitrogen) and MAA level in gnathiids and mucus from several clients [parrotfishes, wrasses (Labridae), and a snapper (Lutjanidae)] were determined. The energetic value of mucus and gnathiids varied among fishes. Overall, carbon, nitrogen, calories, and protein per dry weight were higher in the mucus of most client species compared to gnathiids. Thus, depending on the client species, mucus may be energetically more advantageous for cleaner wrasse to feed on than gnathiids. UV absorbance, a confirmed proxy for MAA levels, indicated high MAA levels in mucus, whereas gnathiids had no detectable MAAs. This suggests that La. dimidiatus obtain MAAs from mucus but not from gnathiids. Hence, in addition to energy, the mucus of some clients also provides La. dimidiatus with the added bonus of UV-absorbing compounds. This may explain why cleaner fish prefer to feed on mucus over gnathiid isopods. The likely costs and benefits to clients of the removal of UV protecting mucus and parasitic gnathiids, respectively, and the variation in benefits gained by cleaner fish from feeding on these foods may explain some variation in cooperation levels in cleaning interactions.

Nitrogen requirements of commercial wine yeast strains during fermentation of a synthetic grape must.

PubMed

Gutiérrez, Alicia; Chiva, Rosana; Sancho, Marta; Beltran, Gemma; Arroyo-López, Francisco Noé; Guillamon, José Manuel

2012-08-01

Nitrogen deficiencies in grape musts are one of the main causes of stuck or sluggish wine fermentations. Currently, the most common method for dealing with nitrogen-deficient fermentations is adding supplementary nitrogen (usually ammonium phosphate). However, it is important to know the specific nitrogen requirement of each strain, to avoid excessive addition that can lead to microbial instability and ethyl carbamate accumulation. In this study, we aimed to determine the effect of increasing nitrogen concentrations of three different nitrogen sources on growth and fermentation performance in four industrial wine yeast strains. This task was carried out using statistical modeling techniques. The strains PDM and RVA showed higher growth-rate and maximum population size and consumed nitrogen much more quickly than strains ARM and TTA. Likewise, the strains PDM and RVA were also the greatest nitrogen demanders. Thus, we can conclude that these differences in nitrogen demand positively correlated with higher growth rate and higher nitrogen uptake rate. The most direct effect of employing an adequate nitrogen concentration is the increase in biomass, which involves a higher fermentation rate. However, the impact of nitrogen on fermentation rate is not exclusively due to the increase in biomass because the strain TTA, which showed the worst growth behavior, had the best fermentation activity. Some strains may adapt a strategy whereby fewer cells with higher metabolic activity are produced. Regarding the nitrogen source used, all the strains showed the better and worse fermentation performance with arginine and ammonium, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

[Screening, identification and phosphate-solubilizing characteristics of phosphate-solubilizing bacteria strain D2 (Pantoea sp.)in rhizosphere of Pinus tabuliformis in iron tailings yard.

PubMed

Wang, Jun Juan; Yan, Ai Hua; Wang, Wei; Li, Ji Quan; Li, Yu Ling

2016-11-18

Two strains of phosphate-solubilizing bacteria were isolated from the rhizosphere of Pinus tabuliformis in iron tailings vegetation restoration areas in Malan Town, Qianan City, Hebei Pro-vince. The bacterial strain D2 with strong phosphate-solubilizing capacity was obtained via screening with plate and shake flask. Based on the morphology, physiology and biochemistry, and the sequence analysis of 16S rDNA, the D2 was identified as a member of Pantoea sp. A fermentation experiment was conducted to investigate the effect of carbon and nitrogen sources on the phosphate-solubilizing capacity of the strain D2; under different nitrogen sources, the organic acids in liquid culture, as well as their types and contents were determined by high performance liquid chromatography. The results showed that the strain D2 was capable of efficiently solubilizing tricalcium phosphate, and the highest value of available phosphorus was up to 392.13 mg·L -1 in liquid culture. The strain D2 displayed the strongest phosphate-solubilizing capability when glucose and ammonium sulfate were used as carbon and nitrogen sources in the culture media, respectively. Under varied nitrogen sources, the resulting organic acids and their types and contents were different. When the nitrogen source in culture media was ammonium sulfate, ammonium chloride, potassium nitrate, sodium nitrate or ammonium nitrate, all four organic acids, including oxalic acid, formic acid, acetic acid and citric acid, were produced. In addition, malic acid was uniquely produced when ammonium sulfate, ammonium chloride or ammonium nitrate was used as the nitrogen source. By Pearson's correlation analysis, a significant positive correlation between the acetic acid content and the available phosphorus content was found (r=0.886, P<0.05), suggesting that acetic acid produced by strain D2 played an important role in promoting inorganic phosphorus dissolution, which was most likely to be one of the important phosphate-solubilizing mechanisms of the strain.

You Can't Get Much from Watching the Radio.

ERIC Educational Resources Information Center

Litten, Larry H.

1988-01-01

Examined sources that students preferred for obtaining information on colleges by interviewing students who had taken the Preliminary Scholastic Aptitude Test in 1983. Enrolled friends were most preferred source of basic information, followed by personal visits, published guides, and admission representatives. Also examined sources on…

Impact of nitrogen reduction measures on nitrogen surplus, income and production of German agriculture.

PubMed

Gömann, H; Kreins, P; Møller, C

2004-01-01

Among the numerous non-point sources of diffuse water pollution with nitrogen, agriculture is counted one of the main sources. The agricultural policies of the Agenda 2000 and a decoupling of direct payments for farmers from their production decisions are exemplarily evaluated as nitrogen reduction measures using the Regional Agricultural and Environmental Information System RAUMIS. The results show that until the target year 2010 the risk of diffuse pollution of water bodies with nitrogen is a regional problem in Germany. These problems are neither mitigated by the policies of Agenda 2000 nor by a decoupling of direct payments from production decisions of farmers. While total nitrogen surplus reduces considerably after a decoupling of direct payments due to decreases of land-use the nitrogen surplus on the remaining cultivated area increases resulting from structural changes. Granting the same amount of direct payments to farmers in both policy alternatives the agricultural sector income would be higher after a decoupling of direct payments opposed to the Agenda 2000 resulting from a more efficient allocation of inputs.

Brucella, nitrogen and virulence.

PubMed

Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques

2016-08-01

The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

Carbon and nitrogen stoichiometry across stream ecosystems

NASA Astrophysics Data System (ADS)

Wymore, A.; Kaushal, S.; McDowell, W. H.; Kortelainen, P.; Bernhardt, E. S.; Johnes, P.; Dodds, W. K.; Johnson, S.; Brookshire, J.; Spencer, R.; Rodriguez-Cardona, B.; Helton, A. M.; Barnes, R.; Argerich, A.; Haq, S.; Sullivan, P. L.; López-Lloreda, C.; Coble, A. A.; Daley, M.

2017-12-01

Anthropogenic activities are altering carbon and nitrogen concentrations in surface waters globally. The stoichiometry of carbon and nitrogen regulates important watershed biogeochemical cycles; however, controls on carbon and nitrogen ratios in aquatic environments are poorly understood. Here we use a multi-biome and global dataset (tropics to Arctic) of stream water chemistry to assess relationships between dissolved organic carbon (DOC) and nitrate, ammonium and dissolved organic nitrogen (DON), providing a new conceptual framework to consider interactions between DOC and the multiple forms of dissolved nitrogen. We found that across streams the total dissolved nitrogen (TDN) pool is comprised of very little ammonium and as DOC concentrations increase the TDN pool shifts from nitrate to DON dominated. This suggests that in high DOC systems, DON serves as the primary source of nitrogen. At the global scale, DOC and DON are positively correlated (r2 = 0.67) and the average C: N ratio of dissolved organic matter (molar ratio of DOC: DON) across our data set is approximately 31. At the biome and smaller regional scale the relationship between DOC and DON is highly variable (r2 = 0.07 - 0.56) with the strongest relationships found in streams draining the mixed temperate forests of the northeastern United States. DOC: DON relationships also display spatial and temporal variability including latitudinal and seasonal trends, and interactions with land-use. DOC: DON ratios correlated positively with gradients of energy versus nutrient limitation pointing to the ecological role (energy source versus nutrient source) that DON plays with stream ecosystems. Contrary to previous findings we found consistently weak relationships between DON and nitrate which may reflect DON's duality as an energy or nutrient source. Collectively these analyses demonstrate how gradients of DOC drive compositional changes in the TDN pool and reveal a high degree of variability in the C: N ratio (3-100) of stream water dissolved organic matter.

Stable Isotopic Composition of Dissolved Organic Nitrogen Fueling Brown Tide in a Semi-Arid Texas Estuary

NASA Astrophysics Data System (ADS)

Campbell, J.; Felix, J. D. D.; Wetz, M.; Cira, E.

2017-12-01

Harmful algal blooms (HABs) have the potential to adversely affect the water quality of estuaries and, consequently, their ability to support healthy and diverse ecosystems. Since the early 1990s, Baffin Bay, a semi-arid south Texas estuary, has progressively experienced harmful algal blooms. The primary species of HAB native to the Baffin Bay region, Aureoumbra lagunensis, is unable to utilize nitrate as a nutrient source, but instead relies on forms of reduced nitrogen (such as dissolved organic nitrogen (DON) and ammonium (NH4+)) for survival. DON levels in Baffin Bay (77 ± 10 µM) exceed the DON concentrations of not only typical Texas estuaries, but estuaries worldwide. Additionally, DON accounts for 90% of the total dissolved nitrogen (TDN) in Baffin Bay, followed by NH4+ at 8%, and NO3-+NO2- contributing 2%. Due to the dependence of A. lagunensis on the reduced forms of nitrogen as an energy source and the elevated concentrations of DON throughout the bay, it is important to identify the origin of this nitrogen as well as how it's being processed as it cycles through the ecosystem. The presented work investigates the stable isotopic composition of reactive nitrogen (Nr) (δ15N-DON, δ15N-NH4+, and δ15N-NO3-) in Baffin Bay samples collected monthly at nine stations over the period of one year. The work provides preliminary evidence of Nr sources and mechanisms driving favorable conditions for HAB proliferation. This information can be useful and applicable to estuarine ecosystems in various settings, advancing scientific progress towards mitigating blooms. Additionally, since the elevated concentrations of DON make Baffin Bay uniquely suited to investigate its sources and processing, this project will aid in characterizing the role of this largely unstudied form of Nr, which could provide insight and change perceptions about the role of DON in nitrogen dynamics.

Atmospheric deposition of selected chemicals and their effect on nonpoint-source pollution in the Twin Cities Metropolitan Area, Minnesota

USGS Publications Warehouse

Brown, R.G.

1984-01-01

The atmospheric contribution to nonpoint-source-runoff pollution of nitrogen, in the form of nitrite-plus-nitrate, and lead was extremely high contributing as much as 84 percent of the runoff load. In contrast, phosphorus and chloride inputs were low averaging of 6 percent of the total runoff load. Future investigations of nonpoint-source pollution in runoff might include collection of data on atmospheric deposition of nitrite-plus-nitrate nitrogen and lead because of the importance of that source of these constituents in runoff.

Treatment of power utilities exhaust

DOEpatents

Koermer, Gerald [Basking Ridge, NJ

2012-05-15

Provided is a process for treating nitrogen oxide-containing exhaust produced by a stationary combustion source by the catalytic reduction of nitrogen oxide in the presence of a reductant comprising hydrogen, followed by ammonia selective catalytic reduction to further reduce the nitrogen oxide level in the exhaust.

Method 440.0 Determination of Carbon and Nitrogen in Sediments and Particulatesof Estuarine/Coastal Waters Using Elemental Analysis

EPA Science Inventory

Elemental analysis is used to determine particulate carbon (PC) and particulate nitrogen (PN) in estuarine and coastal waters and sediment. The method measures the total carbon and nitrogen irrespective of source (inorganic or organic).

Effect of nitrogen regime on microalgal lipid production during mixotrophic growth with glycerol.

PubMed

Paranjape, Kiran; Leite, Gustavo B; Hallenbeck, Patrick C

2016-08-01

Mixotrophic growth of microalgae to boost lipid production is currently under active investigation. Such a process could be of practical importance if a cheap source of organic carbon, such as waste glycerol from biodiesel production, could be used. Several previous studies have already demonstrated that this carbon source can be used by different indigenous strains of microalgae. In this study it is shown that different nitrogen limitation strategies can be applied to further increase lipid production during growth with glycerol. In one strategy, cultures were grown in nitrogen replete medium and then resuspended in nitrogen free medium. In a second strategy, cultures were grown with different initial concentrations of nitrate. Lipid production by the two microalgal strains used, Chlorella sorokiniana (PCH02) and Chlorella vulgaris (PCH05), was shown to be boosted by strategies of nitrogen limitation, but they responded differently to how nitrogen limitation was imposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of Nitrogen Source on NDMA Formation during Chlorination of Diuron

PubMed Central

Chen, Wei-Hsiang; Young, Thomas M.

2009-01-01

N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N′-(3,4-dichlorophenyl)-N, N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitrite < nitrate < ammonium for a given chlorine, nitrogen, and diuron dose. Formation of dichloramine seemed to fully explain enhanced NDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface and groundwater in nitrogen forms and concentrations and disinfection approaches, suggest strategies to reduce NDMA formation should vary with drinking water source. PMID:19457535

Influence of nitrogen source on NDMA formation during chlorination of diuron.

PubMed

Chen, Wei-Hsiang; Young, Thomas M

2009-07-01

N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N'-(3,4-dichlorophenyl)-N,N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitrite

Use of stable isotopes of carbon and nitrogen to identify sources of organic matter to bed sediments of the Tualatin River, Oregon

USGS Publications Warehouse

Bonn, Bernadine A.; Rounds, Stewart A.

2010-01-01

The potential sources of organic matter to bed sediment of the Tualatin River in northwestern Oregon were investigated by comparing the isotopic fractionation of carbon and nitrogen and the carbon/nitrogen ratios of potential sources and bed sediments. Samples of bed sediment, suspended sediment, and seston, as well as potential source materials, such as soil, plant litter, duckweed, and wastewater treatment facility effluent particulate were collected in 1998-2000. Based on the isotopic data, terrestrial plants and soils were determined to be the most likely sources of organic material to Tualatin River bed sediments. The delta 13C fractionation matched well, and although the delta 15N and carbon/nitrogen ratio of fresh plant litter did not match those of bed sediments, the changes expected with decomposition would result in a good match. The fact that the isotopic composition of decomposed terrestrial plant material closely resembled that of soils and bed sediments supports this conclusion. Phytoplankton probably was not a major source of organic matter to bed sediments. Compared to the values for bed sediments, the delta 13C values and carbon/nitrogen ratios of phytoplankton were too low and the delta 15N values were too high. Decomposition would only exacerbate these differences. Although phytoplankton cannot be considered a major source of organic material to bed sediment, a few bed sediment samples in the lower reach of the river showed a small influence from phytoplankton as evidenced by lower delta 13C values than in other bed sediment samples. Isotopic data and carbon/nitrogen ratios for bed sediments generally were similar throughout the basin, supporting the idea of a widespread source such as terrestrial material. The delta 15N was slightly lower in tributaries and in the upper reaches of the river. Higher rates of sediment oxygen demand have been measured in the tributaries in previous studies and coupled with the isotopic data may indicate the presence of more labile organic matter in these areas. Results from this study indicate that strategies to improve oxygen conditions in the Tualatin River are likely to be more successful if they target sources of soil, leaf litter, and other terrestrially derived organic materials to the river rather than the instream growth of algae.

The effect of emission from coal combustion in nonindustrial sources on deposition of sulfur and oxidized nitrogen in Poland.

PubMed

Kryza, Maciej; Werner, Małgorzata; Błaś, Marek; Dore, Anthony J; Sobik, Mieczysław

2010-07-01

Poland has one of the largest sulfur and nitrogen emissions in Europe. This is mainly because coal is a main fuel in industrial and nonindustrial combustion. The aim of this paper is to assess the amount of sulfur and nitrogen deposited from SNAP sector 02 (nonindustrial sources) coal combustion. To assess this issue, the Fine Resolution Atmospheric Multipollutant Exchange (FRAME) model was used. The results suggest that industrial combustion has the largest impact on deposition of oxidized sulfur, whereas the oxidized nitrogen national deposition budget is dominated by transboundary transport. The total mass of pollutants deposited in Poland, originating from nonindustrial coal combustion, is 45 Gg of sulfur and 2.5 Gg of nitrogen, which is over 18% of oxidized sulfur and nearly 2% of oxidized nitrogen deposited. SNAP 02 is responsible for up to 80% of dry-deposited sulfur and 11% of nitrogen. The contribution to wet deposition is largest in central Poland in the case of sulfur and in some areas can exceed 11%. For oxidized nitrogen, nonindustrial emissions contribute less than 1% over the whole area of Poland. The switch from coal to gas fuel in this sector will result in benefits in sulfur and nitrogen deposition reduction.

A Comparison of Technologically Mediated and Face-to-Face Help-Seeking Sources

ERIC Educational Resources Information Center

Reeves, Philip M.; Sperling, Rayne A.

2015-01-01

Background: Current post-secondary school students have access to multiple help-seeking sources. As help-seeking behaviour relates to academic achievement, the provision of preferred help sources would be beneficial to students, instructors, and course designers. Aims: This study examines whether students prefer and intend to utilize…

Kinetic models for nitrogen inhibition in ANAMMOX process on deammonification system

USDA-ARS?s Scientific Manuscript database

The performance of the deammonification process depends on the microbial activity of ammonia oxidizing bacteria (AOB) and ANAMMOX bacteria, and the autotrophic organisms involved in this process have different preferences for substrate, that may cause inhibition or imbalance of the system. The aim o...

40 CFR 418.35 - Standards of performance for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea Subcategory § 418.35... values for 30 consecutive days shall not exceed— Ammonia (as N) 0.53 0.27 Organic nitrogen (as N) .45 .24... Organic nitrogen (as N) .86 .46 Note: Metric units: Kilogram/1,000 kg of product; English units: Pound/1...

Stable isotopes of algae and macroinvertebrates in streams respond to watershed urbanization, inform management goals, and indicate food web relationships

EPA Science Inventory

Watershed development and anthropogenic sources of nitrogen are among leading causes of negative impacts to aquatic ecosystems around the world. The δ15N of aquatic biota can be used as indicators of anthropogenic sources of nitrogen enriched in 15N, but this mostly has bee...

MODELING THE DISTRIBUTION OF NONPOINT NITROGEN SOURCES AND SINKS IN THE NEUSE RIVER BASIN OF NORTH CAROLINA, USA

EPA Science Inventory

This study quantified nonpoint nitrogen (N) sources and sinks across the 14,582 km2 Neuse River Basin (NRB) located in North Carolina, to provide a tabular database to initialize in-stream N decay models and graphic overlay products for the development of management approaches to...

Revising the Evolutionary Stage of HD 163899: The Effects of Convective Overshooting and Rotation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ostrowski, Jakub; Daszyńska-Daszkiewicz, Jadwiga; Cugier, Henryk, E-mail: ostrowski@astro.uni.wroc.pl

We revise the evolutionary status of the B-type supergiant HD 163899 based on the new determinations of the mass–luminosity ratio, effective temperature, and rotational velocity, as well as on the interpretation of the oscillation spectrum of the star. The observed value of the nitrogen-to-carbon abundance fixes the value of the rotation rate of the star. Now, more massive models are strongly preferred than those previously considered, and it is very likely that the star is still in the main-sequence stage. The rotationally induced mixing manifests as the nitrogen overabundance in the atmosphere, which agrees with our analysis of the HARPSmore » spectra. Thus, HD 163899 probably belongs to a group of evolved nitrogen-rich main-sequence stars.« less

Tracking historical increases in nitrogen-driven crop production possibilities

NASA Astrophysics Data System (ADS)

Mueller, N. D.; Lassaletta, L.; Billen, G.; Garnier, J.; Gerber, J. S.

2015-12-01

The environmental costs of nitrogen use have prompted a focus on improving the efficiency of nitrogen use in the global food system, the primary source of nitrogen pollution. Typical approaches to improving agricultural nitrogen use efficiency include more targeted field-level use (timing, placement, and rate) and modification of the crop mix. However, global efficiency gains can also be achieved by improving the spatial allocation of nitrogen between regions or countries, due to consistent diminishing returns at high nitrogen use. This concept is examined by constructing a tradeoff frontier (or production possibilities frontier) describing global crop protein yield as a function of applied nitrogen from all sources, given optimal spatial allocation. Yearly variation in country-level input-output nitrogen budgets are utilized to parameterize country-specific hyperbolic yield-response models. Response functions are further characterized for three ~15-year eras beginning in 1961, and series of calculations uses these curves to simulate optimal spatial allocation in each era and determine the frontier. The analyses reveal that excess nitrogen (in recent years) could be reduced by ~40% given optimal spatial allocation. Over time, we find that gains in yield potential and in-country nitrogen use efficiency have led to increases in the global nitrogen production possibilities frontier. However, this promising shift has been accompanied by an actual spatial distribution of nitrogen use that has become less optimal, in an absolute sense, relative to the frontier. We conclude that examination of global production possibilities is a promising approach to understanding production constraints and efficiency opportunities in the global food system.

Nitrogen Fixation by Anaerobes is Stimulated by Low Oxygen and Insensitive to Combined Nitrogen in Coastal Sediments

NASA Astrophysics Data System (ADS)

Jenkins, B. D.; Spinette, R.; Jones, A.; Puggioni, G.; Ehrlich, A.; Brown, S. M.

2016-02-01

Coastal sediments are typically zones of nitrogen removal via coupled nitrification-denitrification pathways. Increasingly, there are reports of nitrogen fixation in anthropogenically impacted sediments containing ample combined nitrogen. In previous work in the estuarine sediments of Narragansett Bay, we found that anaerobes related to Desulfovibrio spp. and in the Desulfuromonadales express genes for nitrogen fixation (nifH). We also determined that nitrogen fixation rates and gene expression are elevated during periods of seasonal hypoxia. Statistical modeling shows that a combination of elevated phytoplankton biomass as with a duration of hypoxia for a week or longer lead to conditions that promote nitrogen fixation as measured by acetylene reduction. Interestingly, diazotrophs closely related to those identified in Narragansett Bay are present and active in other low oxygen systems, suggesting that expansion of hypoxic events may lead to unanticipated consequences for the benthic nitrogen cycle in many ecosystems. To determine controls on diazotrophy on the organismal level, we isolated and sequenced the genomes of two Narragansett Bay members of the Desulfovibrio. We found that these organisms are insensitive to nitrate and urea, as they are missing the genes to assimilate these nitrogen sources. However, their nitrogen fixation is suppressed by increasing concentrations of ammonium, indicating that they may be sensitive to this nitrogen source in the environment. The paradox of detectable nitrogen fixation in the background of measurable ammonium in estuarine systems is a newly emergent theme and suggests that there are complex microbial interactions and/or structure to the nutrient regimes allowing for fixation.

Magnitudes, nature, and effects of point and nonpoint discharges in the Chattahoochee River basin, Atlanta to West Point Dam, Georgia

USGS Publications Warehouse

Stamer, J.K.; Cherry, R.N.; Faye, R.E.; Kleckner, R.L.

1978-01-01

On an average annual basis and during the storm period of March 12-15, 1976, nonpoint-source loads for most constituents were larger than point-source loads at the Whitesburg station, located on the Chattahoochee River about 40 miles downstream from Atlanta, GA. Most of the nonpoint-source constituent loads in the Atlanta to Whitesburg reach were from urban areas. Average annual point-source discharges accounted for about 50 percent of the dissolved nitrogen, total nitrogen, and total phosphorus loads and about 70 percent of the dissolved phosphorus loads at Whitesburg. During a low-flow period, June 1-2, 1977, five municipal point-sources contributed 63 percent of the ultimate biochemical oxygen demand, and 97 percent of the ammonium nitrogen loads at the Franklin station, at the upstream end of West Point Lake. Dissolved-oxygen concentrations of 4.1 to 5.0 milligrams per liter occurred in a 22-mile reach of the river downstream from Atlanta due about equally to nitrogenous and carbonaceous oxygen demands. The heat load from two thermoelectric powerplants caused a decrease in dissolved-oxygen concentration of about 0.2 milligrams per liter. Phytoplankton concentrations in West Point Lake, about 70 miles downstream from Atlanta, could exceed three million cells per millimeter during extended low-flow periods in the summer with present point-source phosphorus loads. (Woodard-USGS)

Theoretical study of nitrogen-doped graphene nanoflakes: Stability and spectroscopy depending on dopant types and flake sizes.

PubMed

Lin, Chih-Kai

2018-03-05

As nitrogen-doped graphene has been widely applied in optoelectronic devices and catalytic reactions, in this work we have investigated where the nitrogen atoms tend to reside in the material and how they affect the electron density and spectroscopic properties from a theoretical point of view. DFT calculations on N-doped hexagonal and rectangular graphene nanoflakes (GNFs) showed that nitrogen atoms locating on zigzag edges are obviously more stable than those on armchair edges or inside flakes, and interestingly, the N-hydrogenated pyridine moiety could be preferable to pure pyridine moiety in large models. The UV-vis absorption spectra of these nitrogen-doped GNFs display strong dependence on flake sizes, where the larger flakes have their major peaks in lower energy ranges. Moreover, the spectra exhibit different connections to various dopant types and positions: the graphitic-type dopant species present large variety in absorption profiles, while the pyridinic-type ones show extraordinary uniform stability and spectra independent of dopant positions/numbers and hence are hardly distinguishable from each other. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Auxin distribution is differentially affected by nitrate in roots of two rice cultivars differing in responsiveness to nitrogen

PubMed Central

Song, Wenjing; Sun, Huwei; Li, Jiao; Gong, Xianpo; Huang, Shuangjie; Zhu, Xudong; Zhang, Yali; Xu, Guohua

2013-01-01

Background and Aims Although ammonium (NH4+) is the preferred form of nitrogen over nitrate (NO3−) for rice (Oryza sativa), lateral root (LR) growth in roots is enhanced by partial NO3− nutrition (PNN). The roles of auxin distribution and polar transport in LR formation in response to localized NO3− availability are not known. Methods Time-course studies in a split-root experimental system were used to investigate LR development patterns, auxin distribution, polar auxin transport and expression of auxin transporter genes in LR zones in response to localized PNN in ‘Nanguang’ and ‘Elio’ rice cultivars, which show high and low responsiveness to NO3−, respectively. Patterns of auxin distribution and the effects of polar auxin transport inhibitors were also examined in DR5::GUS transgenic plants. Key Results Initiation of LRs was enhanced by PNN after 7 d cultivation in ‘Nanguang’ but not in ‘Elio’. Auxin concentration in the roots of ‘Nanguang’ increased by approx. 24 % after 5 d cultivation with PNN compared with NH4+ as the sole nitrogen source, but no difference was observed in ‘Elio’. More auxin flux into the LR zone in ‘Nanguang’ roots was observed in response to NO3− compared with NH4+ treatment. A greater number of auxin influx and efflux transporter genes showed increased expression in the LR zone in response to PNN in ‘Nanguang’ than in ‘Elio’. Conclusions The results indicate that higher NO3− responsiveness is associated with greater auxin accumulation in the LR zone and is strongly related to a higher rate of LR initiation in the cultivar ‘Nanguang’. PMID:24095838

Chicken feather hydrolysate as an inexpensive complex nitrogen source for PHA production by Cupriavidus necator on waste frying oils.

PubMed

Benesova, P; Kucera, D; Marova, I; Obruca, S

2017-08-01

The chicken feather hydrolysate (FH) has been tested as a potential complex nitrogen source for the production of polyhydroxyalkanoates by Cupriavidus necator H16 when waste frying oil was used as a carbon source. The addition of FH into the mineral salt media with decreased inorganic nitrogen source concentration improved the yields of biomass and polyhydrohyalkanoates. The highest yields were achieved when 10 vol.% of FH prepared by microwave-assisted alkaline hydrolysis of 60 g l -1 feather was added. In this case, the poly(3-hydroxybutyrate) (PHB) yields were improved by more than about 50% as compared with control cultivation. A positive impact of FH was also observed for accumulation of copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) when sodium propionate was used as a precursor. The copolymer has superior processing and mechanical properties in comparison with PHB homopolymer. The application of FH eliminated the inhibitory effect of propionate and resulted in altered content of 3-hydroxyvalerate (3HV) in copolymer. Therefore, the hydrolysed feather can serve as an excellent complex source of nitrogen for the polyhydroxyalkanoates (PHA) production. Moreover, by the combination of two inexpensive types of waste, such as waste frying oil and feather hydrolysate, it is possible to produce PHA with substantially improved efficiency and sustainability. Millions of tons of feathers, important waste product of poultry-processing industry, are disposed off annually without any further benefits. Thus, there is an inevitable need for new technologies that enable ecologically and economically sensible processing of this waste. Herein, we report that alkali-hydrolysed feathers can be used as a complex nitrogen source considerably improving polyhydroxyalkanoates production on waste frying oil employing Cupriavidus necator. © 2017 The Society for Applied Microbiology.

The potential of carbon and nitrogen isotopes to conservatively discriminate between subsoil sediment sources

NASA Astrophysics Data System (ADS)

Laceby, J. Patrick; Olley, Jon

2013-04-01

Moreton Bay, in South East Queensland, Australia, is a Ramsar wetland of international significance. A decline of the bay's ecosystem health has been primarily attributed to sediments and nutrients from catchment sources. Sediment budgets for three catchments indicated gully erosion dominates the supply of sediment in Knapp Creek and the Upper Bremer River whereas erosion from cultivated soils is the primary sediment source in Blackfellow Creek. Sediment tracing with fallout-radionuclides confirmed subsoil erosion processes dominate the supply of sediment in Knapp Creek and the Upper Bremer River whereas in Blackfellow Creek cultivated and subsoil sources contribute >90% of sediments. Other sediment properties are required to determine the relative sediment contributions of channel bank, gully and cultivated sources in these catchments. The potential of total organic carbon (TOC), total nitrogen (TN), and carbon and nitrogen stable isotopes (δ13C, δ15N) to conservatively discriminate between subsoil sediment sources is presented. The conservativeness of these sediment properties was examined through evaluating particle size variations in depth core soil samples and investigating whether they remain constant in source soils over two sampling occasions. Varying conservative behavior and source discrimination was observed. TN in the

Volcano fixes nitrogen into plant-available forms

USGS Publications Warehouse

Huebert, B.; Vitousek, P.; Sutton, J.; Elias, T.; Heath, J.; Coeppicus, S.; Howell, S.; Blomquist, B.

1999-01-01

Hawaiian montane ecosystems developing on recent tephra deposits contain more fixed nitrogen than conventional sources can explain. Heath and Huebert (1999) demonstrated that cloud water interception is the mechanism by which this extra nitrogen is deposited, but could not identify its source. We show here that atmospheric dinitrogen is fixed at the surface of active lava flows, producing concentrations of NO which are higher than those found in most urban rush hour air pollution. Over a period of hours this NO is blown away from the island and oxidized to nitrate. Interruptions in the trade wind flow can return this nitrate to the island to be deposited in cloud water. Thus, fixation on active lava flows is able to provide nitrogen to developing ecosystems on flows emplaced earlier.

Improving nitrogen management for corn in southern Idaho and southwest Oregon

USDA-ARS?s Scientific Manuscript database

Funding is being sought from multiple sources to update nitrogen fertilizer recommendations for irrigated corn in southern Idaho and southwest Oregon. This paper summarizes the justifications and main objectives of this proposed research. Nitrogen needs to be correctly managed in corn production sys...

Using stable isotopes in tracing contaminant sources in an industrial area: A case study on the hydrological basin of the Olt River, Romania.

PubMed

Popescu, Raluca; Mimmo, Tanja; Dinca, Oana Romina; Capici, Calogero; Costinel, Diana; Sandru, Claudia; Ionete, Roxana Elena; Stefanescu, Ioan; Axente, Damian

2015-11-15

Tracing pollution sources and transformation of nitrogen compounds in surface- and groundwater is an issue of great significance worldwide due to the increased human activity, translated in high demand of water resources and pollution. In this work, the hydrological basin of an important chemical industrial platform in Romania (Ramnicu Valcea industrial area) was characterized in terms of the physico-chemical and isotope composition of δ(18)O and δ(2)H in water samples and δ(15)N of the inorganic nitrogen species. Throughout a period of one year, water samples from the Olt River and its more important tributaries were collected monthly in the industrial area, when the seasonal and spatial isotope patterns of the surface waters and the main sources of pollution were determined. Higher inorganic nitrogen concentrations (up to 10.2 mg N L(-1)) were measured between November 2012 and April 2013, which were designated as anthropogenic additions using the mixing calculations. The main sources of pollution with inorganic nitrogen were agriculture and residential release. The inorganic nitrogen from the industrial waste water duct had a distinct δ(15)N fingerprint (mean of -8.6‰). Also, one industrial release into the environment was identified for Olt River, at Ionesti site, in November 2012. The mean precipitation samples had the lowest inorganic nitrogen concentrations (less than 5.5 mg N L(-1)) with a distinct δ(15)N fingerprint compared to the surface and industrial waters. Copyright © 2015 Elsevier B.V. All rights reserved.

Trimethylamine and trimethylamine N-oxide are supplementary energy sources for a marine heterotrophic bacterium: implications for marine carbon and nitrogen cycling.

PubMed

Lidbury, Ian D E A; Murrell, J Colin; Chen, Yin

2015-03-01

Bacteria of the marine Roseobacter clade are characterised by their ability to utilise a wide range of organic and inorganic compounds to support growth. Trimethylamine (TMA) and trimethylamine N-oxide (TMAO) are methylated amines (MA) and form part of the dissolved organic nitrogen pool, the second largest source of nitrogen after N2 gas, in the oceans. We investigated if the marine heterotrophic bacterium, Ruegeria pomeroyi DSS-3, could utilise TMA and TMAO as a supplementary energy source and whether this trait had any beneficial effect on growth. In R. pomeroyi, catabolism of TMA and TMAO resulted in the production of intracellular ATP which in turn helped to enhance growth rate and growth yield as well as enhancing cell survival during prolonged energy starvation. Furthermore, the simultaneous use of two different exogenous energy sources led to a greater enhancement of chemoorganoheterotrophic growth. The use of TMA and TMAO primarily as an energy source resulted in the remineralisation of nitrogen in the form of ammonium, which could cross feed into another bacterium. This study provides greater insight into the microbial metabolism of MAs in the marine environment and how it may affect both nutrient flow within marine surface waters and the flux of these climatically important compounds into the atmosphere.

Enhancement of docosahexaenoic acid (DHA) production from Schizochytrium sp. S31 using different growth medium conditions.

PubMed

Sahin, Deniz; Tas, Ezgi; Altindag, Ulkü Hüma

2018-01-24

Schizochytrium species is one of the most studied microalgae for production of docosahexaenoic acid (DHA) which is an omega-3 fatty acid with positive effects for human health. However, high cost and low yield in production phase makes optimization of cultivation process inevitable. We focus on the optimization of DHA production using Schizochytrium sp. using different media supplements; glucose, fructose and glycerol as carbon variants, proteose peptone and tryptone as nitrogen variants. The highest biomass (5.61 g/L) and total fatty acid yield (1.74 g/L) were obtained in proteose peptone medium which was used as the alternative nitrogen source instead of yeast extract. The highest DHA yield (0.40 g/L) was achieved with glycerol as the carbon source although it had the second lowest biomass production after ethanol containing medium. Ethanol, as an alternative carbon source and a precursor for acetyl-CoA, increased DHA percentage in total lipid content from 29.94 to 40.04% but decreasing the biomass drastically. Considering different carbon and nitrogen sources during cultivation of Schizochytrium sp. will improve DHA production. Combination of proteose peptone and glycerol as nitrogen and carbon sources, respectively, and addition of ethanol with a proper timing will be useful to have higher DHA yield.

Coupled effects of methane monooxygenase and nitrogen source on growth and poly-β-hydroxybutyrate (PHB) production of Methylosinus trichosporium OB3b.

PubMed

Zhang, Tingting; Zhou, Jiti; Wang, Xiaowei; Zhang, Yu

2017-02-01

The coupled effects of nitrogen source and methane monooxygenase (MMO) on the growth and poly-β-hydroxybutyrate (PHB) accumulation capacity of methanotrophs were explored. The ammonia-supplied methanotrophs expressing soluble MMO (sMMO) grew at the highest rate, while N 2 -fixing bacteria expressing particulate MMO (pMMO) grew at the lowest rate. Further study showed that more hydroxylamine and nitrite was formed by ammonia-supplied bacteria containing pMMO, which might cause their slightly lower growth rate. The highest PHB content (51.0%) was obtained under nitrogen-limiting conditions with the inoculation of nitrate-supplied bacteria containing pMMO. Ammonia-supplied bacteria also accumulated a higher content of PHB (45.2%) with the expression of pMMO, while N 2 -fixing bacteria containing pMMO only showed low PHB production capacity (32.1%). The maximal PHB contents of bacteria expressing sMMO were low, with no significant change under different nitrogen source conditions. The low MMO activity, low cell growth rate and low PHB production capacity of methanotrophs continuously cultivated with N 2 with the expression of pMMO were greatly improved in the cyclic NO 3 - N 2 cultivation regime, indicating that long-term deficiency of nitrogen sources was detrimental to the activity of methanotrophs expressing pMMO. Copyright © 2016. Published by Elsevier B.V.

Estimated water and nutrient inflows and outflows, Lake Cochituate, eastern Massachusetts, 1977-79

USGS Publications Warehouse

Gay, F.B.

1984-01-01

Streamflow was the major source of water and nutrients (nitrogen and phosphorus) to Lake Cochituate, followed by ground water, and then precipitation during April 1978 through March 1979. Compared to all sources during that period, streams contributed 7,217 million gallons (a little over 82 percent) of water, 63 ,000 pounds (between 50 and 60 percent) of nitrogen, and 3,000 pounds (94 percent) of phosphorus. A little over 60 percent of all the water that entered Lake Cochituate flowed from Fisk Pond. This single source transported about 38,000 pounds of nitrogen and 2,000 pounds of phosphorus. Ground-water inflow to Lake Cochituate occurs along its shoreline except at the north end of Lake Cochituate 's North Pond where natural seepage from the lake is occurring and at locations on the lake 's Middle and South Ponds where municipal wells induce infiltration of lake water amounting to 1,228 million gallons for that period. Discharge of ground water to the lake was estimated to range from 462 to 816 million gallons and transported from 31,000 to 55,000 pounds of nitrogen and from 46 to 82 pounds of phosphorus. Bulk precipitation was estimated to contribute about the same volume of water to the lake as ground water but double its phosphorus load. However, the load of nitrogen, 8000 pounds, from bulk precipitation was the smallest of any source. (USGS)

Simulation on Change Law of Runoff, Sediment and Non-point Source Nitrogen and Phosphorus Discharge under Different Land uses Based on SWAT Model: A Case Study of Er hai Lake Small Watershed

NASA Astrophysics Data System (ADS)

Tong, Xiao Xia; Lai Cui, Yuan; Chen, Man Yu; Hu, Bo; Xu, Wen Sheng

2018-05-01

The Er yuan watershed of Er hai district is chosen as the research area, the law of runoff and sediment and non-point source nitrogen and phosphorus discharges under different land uses during 2001 to 2014 are simulated based on SWAT model. Results of simulation indicate that the order of total runoff yield of different land use type from high to low is grassland, paddy fields, dry land. Specifically, the order of surface runoff yield from high to low is paddy fields, dry land, grassland, the order of lateral runoff yield from high to low is paddy fields, dry land, grassland, the order of groundwater runoff yield from high to low is grassland, paddy fields, dry land. The orders of sediment and nitrogen and phosphorus yield per unit area of different land use type are the same, grassland> paddy fields> dry land. It can be seen, nitrogen and phosphorus discharges from paddy fields and dry land are the main sources of agricultural non-point pollution of the irrigated area. Therefore, reasonable field management measures which can decrease the discharge of nitrogen and phosphorus of paddy fields and dry land are the key to agricultural non-point source pollution prevention and control.

Favourable culture conditions for mycelial growth of Hydnum repandum, a medicinal mushroom.

PubMed

Peksen, Aysun; Kibar, Beyhan; Yakupoglu, Gokcen

2013-01-01

In this study, factors such as pH, temperature, carbon and nitrogen sources that affect mycelial growth of Hydnum repandum, a medicinal mushroom, were investigated. Different inoculum media for vegetative inoculum production were also examined. The best suitable pH for mycelial growth was found to be 5.5. Among constant temperatures, the best mycelial growth was obtained at 20 and 25°C. The mycelial growth drastically decreased at 15°C, and no mycelia were obtained at 30°C. Glucose and mannitol were found to be the most suitable carbon sources. Ca(NO3)2 as a nitrogen source gave the best results for mycelial growth. The poorest mycelial growth was noted in sucrose and xylose as carbon sources and in NH4NO3 and (NH4)2HPO4 as nitrogen sources. Peat and peat: vermiculite mixtures (1:4, 1:6, 1:8 and 1:10, v:v) were the best media to use in producing the vegetative inoculum of H. repandum.

Urea and urine are a viable and cost-effective nitrogen source for Yarrowia lipolytica biomass and lipid accumulation.

PubMed

Brabender, Matthew; Hussain, Murtaza Shabbir; Rodriguez, Gabriel; Blenner, Mark A

2018-03-01

Yarrowia lipolytica is an industrial yeast that has been used in the sustainable production of fatty acid-derived and lipid compounds due to its high growth capacity, genetic tractability, and oleaginous properties. This investigation examines the possibility of utilizing urea or urine as an alternative to ammonium sulfate as a nitrogen source to culture Y. lipolytica. The use of a stoichiometrically equivalent concentration of urea in lieu of ammonium sulfate significantly increased cell growth when glucose was used as the carbon source. Furthermore, Y. lipolytica growth was equally improved when grown with synthetic urine and real human urine. Equivalent or better lipid production was achieved when cells are grown on urea or urine. The successful use of urea and urine as nitrogen sources for Y. lipolytica growth highlights the potential of using cheaper media components as well as exploiting and recycling non-treated human waste streams for biotechnology processes.

Hydrodesulfurization of chlorinized coal

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Rohatgi, N. K. (Inventor)

1983-01-01

A method of desulfurization is described in which high sulfur coals are desulfurized by low temperature chlorinolysis of coal in liquid media, preferably water, followed by hydrodesulfurization at a temperature above 500 C. The coals are desulfurized to an extent of up to 90% by weight and simultaneously dechlorinated to a chlorine content below 0.1% by weight. The product coals have lower volatiles loss, lower oxygen and nitrogen content and higher fixed carbon than raw coals treated with hydrogen under the same conditions. Heating the chlorinated coal to a temperature above 500 C. in inert gas such as nitrogen results in significantly less desulfurization.

Optical remote diagnostics of atmospheric propagating beams of ionizing radiation

DOEpatents

Karl JR., Robert R.

1990-03-06

Data is obtained for use in diagnosing the characteristics of a beam of ionizing radiation, such as charged particle beams, neutral particle beams, and gamma ray beams. In one embodiment the beam is emitted through the atmosphere and produces nitrogen fluorescence during passage through air. The nitrogen fluorescence is detected along the beam path to provide an intensity from which various beam characteristics can be calculated from known tabulations. Optical detecting equipment is preferably located orthogonal to the beam path at a distance effective to include the entire beam path in the equipment field of view.

Optical remote diagnostics of atmospheric propagating beams of ionizing radiation

DOEpatents

Karl, Jr., Robert R.

1990-01-01

Data is obtained for use in diagnosing the characteristics of a beam of ionizing radiation, such as charged particle beams, neutral particle beams, and gamma ray beams. In one embodiment the beam is emitted through the atmosphere and produces nitrogen fluorescence during passage through air. The nitrogen fluorescence is detected along the beam path to provide an intensity from which various beam characteristics can be calculated from known tabulations. Optical detecting equipment is preferably located orthogonal to the beam path at a distance effective to include the entire beam path in the equipment field of view.

Use of zinc and copper (I) salts to reduce sulfur and nitrogen impurities during the pyrolysis of plastic and rubber waste to hydrocarbons

DOEpatents

Wingfield, Jr., Robert C.; Braslaw, Jacob; Gealer, Roy L.

1984-01-01

An improvement in a process for the pyrolytic conversion of rubber and plastic waste to hydrocarbon products which results in reduced levels of nitrogen and sulfur impurities in these products. The improvement comprises pyrolyzing the waste in the presence of at least about 1 weight percent of salts, based on the weight of the waste, preferably chloride or carbonate salts, of zinc or copper (I). This invention was made under contract with or subcontract thereunder of the Department of Energy Contract #DE-AC02-78-ER10049.

Diatom feeding across trophic guilds in tidal flat nematodes, and the importance of diatom cell size

NASA Astrophysics Data System (ADS)

Moens, Tom; Vafeiadou, Anna-Maria; De Geyter, Ellen; Vanormelingen, Pieter; Sabbe, Koen; De Troch, Marleen

2014-09-01

We examine the capacity of nematodes from three feeding types (deposit feeder, epistrate feeder, predator) to utilize microphytobenthos (MPB), and assess whether diatom cell size and consumer body size are important drivers of their feeding. We analyzed natural stable isotope ratios of carbon and nitrogen in abundant nematode genera and a variety of carbon sources at an estuarine intertidal flat. All nematodes had δ13C indicating that MPB is their major carbon source. δ15N, however, demonstrated that only one deposit and one epistrate feeder genus obtained most of their carbon from direct grazing on MPB, whereas other deposit feeders and predators obtained at least part of their carbon by predation on MPB grazers. We then performed a microcosm experiment in which equal cell numbers of each of three differently sized strains of the pennate diatom Seminavis were offered as food to four, one and one genera of deposit feeders, epistrate feeders and predators, respectively. Previous studies have shown that all but the epistrate feeder ingest whole diatoms, whereas the epistrate feeder pierces cells and sucks out their contents. Most genera showed markedly higher carbon absorption from medium and large cells than from small ones. When considering the number of cells consumed, however, none of the nematodes which ingest whole cells exhibited a clear preference for any specific diatom size. The epistrate feeder was the smallest nematode taxon considered here, yet it showed a marked preference for large cells. These results highlight that the feeding mechanism is much more important than consumer size as a driver of particle size selection in nematodes grazing MPB.

Nutrient co-limited Trichodesmium as nitrogen source or sink in a future ocean.

PubMed

Walworth, Nathan G; Fu, Fei-Xue; Lee, Michael D; Cai, Xiaoni; Saito, Mak A; Webb, Eric A; Hutchins, David A

2017-11-27

Nitrogen-fixing (N 2 ) cyanobacteria provide bioavailable nitrogen to vast ocean regions but are in turn limited by iron (Fe) and/or phosphorus (P), which may force them to employ alternative nitrogen acquisition strategies. The adaptive responses of nitrogen-fixers to global-change drivers under nutrient-limited conditions could profoundly alter the current ocean nitrogen and carbon cycles. Here, we show that the globally-important N 2 -fixer Trichodesmium fundamentally shifts nitrogen metabolism towards organic-nitrogen scavenging following long-term high-CO 2 adaptation under iron and/or phosphorus (co)-limitation. Global shifts in transcripts and proteins under high CO 2 /Fe-limited and/or P-limited conditions include decreases in the N 2 -fixing nitrogenase enzyme, coupled with major increases in enzymes that oxidize trimethylamine (TMA). TMA is an abundant, biogeochemically-important organic nitrogen compound that supports rapid Trichodesmium growth while inhibiting N 2 fixation. In a future high-CO 2 ocean, this whole-cell energetic reallocation towards organic nitrogen scavenging and away from N 2 -fixation may reduce new-nitrogen inputs by Trichodesmium , while simultaneously depleting the scarce fixed-nitrogen supplies of nitrogen-limited open ocean ecosystems. Importance Trichodesmium is among the most biogeochemically-significant microorganisms in the ocean, since it supplies up to 50% of the new nitrogen supporting open ocean food webs. We used Trichodesmium cultures adapted to high CO 2 for 7 years followed by additional exposure to iron and/or phosphorus (co)-limitation. We show that 'future ocean' conditions of high CO 2 and concurrent nutrient limitation(s) fundamentally shift nitrogen metabolism away from nitrogen fixation, and instead towards upregulation of organic-nitrogen scavenging pathways. We show that Trichodesmium's responses to projected future ocean conditions include decreases in the nitrogen-fixing nitrogenase enzymes, coupled with major increases in enzymes that oxidize the abundant organic nitrogen source trimethylamine (TMA). Such a shift towards organic nitrogen uptake and away from nitrogen fixation may substantially reduce new-nitrogen inputs by Trichodesmium to the rest of the microbial community in the future high-CO 2 ocean, with potential global implications for ocean carbon and nitrogen cycling. Copyright © 2017 American Society for Microbiology.

Women’s Preferred Sources for Primary and Mental Health Care: Implications for Reproductive Health Providers

PubMed Central

Harris, Lisa H.; Dalton, Vanessa K.

2016-01-01

Purpose To describe women’s preferences for reproductive health providers as sources of primary and mental health care. Methods Secondary data analysis of the Women’s Health Care Experiences and Preferences Study, an internet survey conducted in September 2013 of 1,078 women aged 18–55 randomly sampled from a U.S. national probability panel. We estimated women’s preferred and usual sources of care (reproductive health providers, generalists, other) for various primary care and mental health care services using weighted statistics and multiple logistic regression. Main Findings Among women using healthcare in the past five years (n=981), 88% received primary and/or mental health care, including routine medical check-up (78%), urgent/acute (48%), chronic disease (27%), depression/anxiety (21%), stress (16%), and IPV (2%) visits. Of those, reproductive health providers were the source of check-up (14%), urgent/acute (3%), chronic disease (6%), depression/anxiety (6%), stress (11%), and intimate partner violence (3%) services. Preference for specific reproductive health-provided primary/mental health care services ranged from 7–20%. Among women having used primary/mental health care services (N=894), more women (1–17%) preferred than had received primary/mental health care from reproductive health providers. Nearly a quarter (22%) identified reproductive health providers as their single most preferred source of care. Contraceptive use was the strongest predictor of preference for reproductive health-provided primary/mental health care (Odds Ratios range 2.11–3.30). Conclusions Reproductive health providers are the sole source of healthcare for a substantial proportion of reproductive-aged women – the same groups at risk for unmet primary and mental health care needs. Findings have implications for reproductive health providers’ role in comprehensive women’s healthcare provision and potentially for informing patient-centered, integrated models of care in current health systems. PMID:27825589

Effects of UPR and ERAD pathway on the prolyl endopeptidase production in Pichia pastoris by controlling of nitrogen source.

PubMed

Wang, Xiao-Dong; Jiang, Ting; Yu, Xiao-Wei; Xu, Yan

2017-07-01

Prolyl endopeptidase (PEP) is very useful in various industries, while the high cost of enzyme production remains a major obstacle for its industrial applications. Pichia pastoris has been used for the PEP production; however, the fermentation process has not be investigated and little is known about the impact of excessive PEP production on the host cell physiology. Here, we optimized the nitrogen source to improve the PEP expression level and further evaluated the cellular response including UPR and ERAD. During methanol induction phase the PEP activity (1583 U/L) was increased by 1.48-fold under the optimized nitrogen concentration of NH 4 + (300 mmol/L) and casamino acids [1.0% (w/v)] in a 3-L bioreactor. Evaluated by RT-PCR the UPR and ERAD pathways were confirmed to be activated. Furthermore, a strong decrease of ERAD-related gene transcription was observed with the addition of nitrogen source, which contributed to a higher PEP expression level.

Evaluation of natural materials as exogenous carbon sources for biological treatment of low carbon-to-nitrogen wastewater.

PubMed

Ramírez-Godínez, Juan; Beltrán-Hernández, Icela; Álvarez-Hernández, Alejandro; Coronel-Olivares, Claudia; Contreras-López, Elizabeth; Quezada-Cruz, Maribel; Vázquez-Rodríguez, Gabriela

2015-01-01

In the bacterial processes involved in the mitigation of nitrogen pollution, an adequately high carbon-to-nitrogen (C : N) ratio is key to sustain denitrification. We evaluated three natural materials (woodchips, barley grains, and peanut shells) as carbon sources for low C : N wastewater. The amount of organic matter released from these materials to aqueous media was evaluated, as well as their pollution swapping potential by measuring the release of total Kjeldahl nitrogen, N-NH4 (+), NO2 (-), and NO3 (-), and total phosphorous. Barley grains yielded the highest amount of organic matter, which also showed to be the most easily biodegradable. Woodchips and peanut shells released carbon rather steadily and so they would not require frequent replenishment from biological reactors. These materials produced eluates with lower concentrations of nutrients than the leachates from barley grains. However, as woodchips yielded lower amounts of suspended solids, they constitute an adequate exogenous source for the biological treatment of carbon-deficient effluents.

Evaluation of Natural Materials as Exogenous Carbon Sources for Biological Treatment of Low Carbon-to-Nitrogen Wastewater

PubMed Central

Ramírez-Godínez, Juan; Beltrán-Hernández, Icela; Álvarez-Hernández, Alejandro; Coronel-Olivares, Claudia; Contreras-López, Elizabeth; Quezada-Cruz, Maribel

2015-01-01

In the bacterial processes involved in the mitigation of nitrogen pollution, an adequately high carbon-to-nitrogen (C : N) ratio is key to sustain denitrification. We evaluated three natural materials (woodchips, barley grains, and peanut shells) as carbon sources for low C : N wastewater. The amount of organic matter released from these materials to aqueous media was evaluated, as well as their pollution swapping potential by measuring the release of total Kjeldahl nitrogen, N-NH4 +, NO2 −, and NO3 −, and total phosphorous. Barley grains yielded the highest amount of organic matter, which also showed to be the most easily biodegradable. Woodchips and peanut shells released carbon rather steadily and so they would not require frequent replenishment from biological reactors. These materials produced eluates with lower concentrations of nutrients than the leachates from barley grains. However, as woodchips yielded lower amounts of suspended solids, they constitute an adequate exogenous source for the biological treatment of carbon-deficient effluents. PMID:26495313

Termites create spatial structure and govern ecosystem function by affecting N2 fixation in an East African savanna.

PubMed

Fox-Dobbs, Kena; Doak, Daniel F; Brody, Alison K; Palmer, Todd M

2010-05-01

The mechanisms by which even the clearest of keystone or dominant species exert community-wide effects are only partially understood in most ecosystems. This is especially true when a species or guild influences community-wide interactions via changes in the abiotic landscape. Using stable isotope analyses, we show that subterranean termites in an East African savanna strongly influence a key ecosystem process: atmospheric nitrogen fixation by a monodominant tree species and its bacterial symbionts. Specifically, we applied the 15N natural abundance method in combination with other biogeochemical analyses to assess levels of nitrogen fixation by Acacia drepanolobium and its effects on co-occurring grasses and forbs in areas near and far from mounds and where ungulates were or were not excluded. We find that termites exert far stronger effects than do herbivores on nitrogen fixation. The percentage of nitrogen derived from fixation in Acacia drepanolobium trees is higher (55-80%) away from mounds vs. near mounds (40-50%). Mound soils have higher levels of plant available nitrogen, and Acacia drepanolobium may preferentially utilize soil-based nitrogen sources in lieu of fixed nitrogen when these sources are readily available near termite mounds. At the scale of the landscape, our models predict that termite/soil derived nitrogen sources influence >50% of the Acacia drepanolobium trees in our system. Further, the spatial extent of these effects combine with the spacing of termite mounds to create highly regular patterning in nitrogen fixation rates, resulting in marked habitat heterogeneity in an otherwise uniform landscape. In summary, we show that termite-associated effects on nitrogen processes are not only stronger than those of more apparent large herbivores in the same system, but also occur in a highly regular spatial pattern, potentially adding to their importance as drivers of community and ecosystem structure.

A facile approach towards increasing the nitrogen-content in nitrogen-doped carbon nanotubes via halogenated catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ombaka, L.M.; Ndungu, P.G.; Department of Applied Chemistry, Doornfontein Campus, University of Johannesburg, P.O. Box 17011, Johannesburg 2028

Nitrogen-doped carbon nanotubes (N-CNTs) have been synthesized at 850 °C via a CVD deposition technique by use of three ferrocenyl derivative catalysts, i.e. para-CN, -CF{sub 3} and -Cl substituted-phenyl rings. The synthesized catalysts have been characterized by NMR, IR, HR-MS and XRD. The XRD analysis of the para-CF{sub 3} catalyst indicates that steric factors influence the X-ray structure of 1,1′-ferrocenylphenyldiacrylonitriles. Acetonitrile or pyridine was used as carbon and nitrogen sources to yield mixtures of N-CNTs and carbon spheres (CS). The N-CNTs obtained from the para-CF{sub 3} catalysts, in pyridine, have the highest nitrogen-doping level, show a helical morphology and aremore » less thermally stable compared with those synthesized by use of the para-CN and -Cl as catalyst. This suggests that fluorine heteroatoms enhance nitrogen-doping in N-CNTs and formation of helical-N-CNTs (H-N-CNTs). The para-CF{sub 3} and para-Cl catalysts in acetonitrile yielded iron-filled N-CNTs, indicating that halogens promote encapsulation of iron into the cavity of N-CNT. The use of acetonitrile, as carbon and nitrogen source, with the para-CN and -Cl as catalysts also yielded a mixture of N-CNTs and carbon nanofibres (CNFs), with less abundance of CNFs in the products obtained using para-Cl catalysts. However, para-CF{sub 3} catalyst in acetonitrile gave N-CNTs as the only shaped carbon nanomaterials. - Graphical abstract: Graphical abstract showing the synthesis of N-CNTs using halogenated-ferrocenyl derivatives as catalyst with pyridine or acetonitrile as nitrogen and carbon sources via the chemical vapour deposition technique. - Highlights: • N-CNTs were synthesized from halogenated ferrocenyl catalysts. • Halogenated catalysts promote nitrogen-doping and pyridinic nitrogen in N-CNTs. • Halogenated catalysts facilitate iron filling of N-CNTs.« less

Nitrogen mineralization and geochemical characteristics of amino acids in surface sediments of a typical polluted area in the Haihe River Basin, China.

PubMed

Zhao, Yu; Shan, Baoqing; Tang, Wenzhong; Zhang, Hong

2015-11-01

Studies of nitrogen mineralization and diagenetic status of organic matter evaluated by total hydrolysable amino acids (THAAs) were designed to test the hypothesis that nitrogen mineralization in sediments was a potential source of ammonium in strongly artificially disturbed rivers such as the Ziya River watershed. Ammonium and organic nitrogen in both water and sediment samples were the major forms of nitrogen in the watershed. NH3-N was significantly correlated with organic nitrogen in both water (R = 0.823, P < 0.01) and sediments (R = 0.787, P < 0.01). Organic nitrogen with an average content of 3,275.21 ± 1,476.10 mg · kg(-1), accounted for 82.73 % of total nitrogen (TN) in sediments. Organic nitrogen was a potential source of ammonia release into overlying water. Nitrogen mineralization experiments showed that accumulated dissolved inorganic nitrogen ranged from 326.15 to 545.72 mg · kg(-1) and accumulated NH3-N ranged from 320.95 to 533.93 mg · kg(-1). Most of the mineralized nitrogen was NH3-N ( approximately 98.17%) and mineralized nitrogen in sediments ranged from 6.20 to 22.10% of TN. Twenty amino acids were detected, accounting for 45.70 % of organic nitrogen. Protein amino acids, accounting for 89.22% of THAAs, were the dominant THAAs in sediments. The ratio of L-glutamic acid to γ-aminobutyric acid and degradation index showed that the organic matter was poorly degraded and presented a high potential risk of ammonium mineralization.

Leishmania infantum Asparagine Synthetase A Is Dispensable for Parasites Survival and Infectivity.

PubMed

Faria, Joana; Loureiro, Inês; Santarém, Nuno; Macedo-Ribeiro, Sandra; Tavares, Joana; Cordeiro-da-Silva, Anabela

2016-01-01

A growing interest in asparagine (Asn) metabolism has currently been observed in cancer and infection fields. Asparagine synthetase (AS) is responsible for the conversion of aspartate into Asn in an ATP-dependent manner, using ammonia or glutamine as a nitrogen source. There are two structurally distinct AS: the strictly ammonia dependent, type A, and the type B, which preferably uses glutamine. Absent in humans and present in trypanosomatids, AS-A was worthy of exploring as a potential drug target candidate. Appealingly, it was reported that AS-A was essential in Leishmania donovani, making it a promising drug target. In the work herein we demonstrate that Leishmania infantum AS-A, similarly to Trypanosoma spp. and L. donovani, is able to use both ammonia and glutamine as nitrogen donors. Moreover, we have successfully generated LiASA null mutants by targeted gene replacement in L. infantum, and these parasites do not display any significant growth or infectivity defect. Indeed, a severe impairment of in vitro growth was only observed when null mutants were cultured in asparagine limiting conditions. Altogether our results demonstrate that despite being important under asparagine limitation, LiAS-A is not essential for parasite survival, growth or infectivity in normal in vitro and in vivo conditions. Therefore we exclude AS-A as a suitable drug target against L. infantum parasites.

Electron Heating Mode Transitions in Nitrogen (13.56 and 40.68) MHz RF-CCPs

NASA Astrophysics Data System (ADS)

Erozbek Gungor, Ummugul; Bilikmen, Sinan Kadri; Akbar, Demiral

2015-09-01

Capacitively coupled radio frequency plasmas (RF-CCPs) are commonly used in plasma material processing. Parametrical structure of the plasma determines the demands of processing applications. For example; high density plasmas in gamma mode are mostly preferred for etching applications while stabile plasmas in gamma mode are usually used in sputtering applications. For this reason, characterization of the plasma is very essential before surface modification of the materials. In this work, analysis of electron heating mode transition in high frequency (40.68 MHz) RF-CCP was deeply investigated. The plasma was generated in a home-made (500 × 400 mm2) stainless steel cylindrical reactor in which two identical (200 mm in diameter) electrodes were placed with 40 mm interval. In addition, L-type automatic matching network system was connected to the 40.68 MHz RF generator to get high accuracy. Moreover, the pure (99.995 %) nitrogen was used as an activation gas on account of having an appreciable impression in plasma processing applications. Furthermore, diagnostic measurements of the plasma were done by using the Impedans Langmuir single and double probe systems. It was found that two transition points; α- γ (pressure dependent) and γ- α (RF power dependent) were observed in both medium and high RF-CCPs. As a result, the α- γ pressure transition increased, whereas the γ- α power transition remained constant by changing the RF frequency sources.

Biological and physiological characteristics of Neotyphodium gansuense symbiotic with Achnatherum inebrians.

PubMed

Li, Chunjie; Nan, Zhibiao; Li, Fei

2008-01-01

Biological and physiological characteristics of Neotyphodium gansuense were compared with Neotyphodium coenophialum and Epichloë festucae at a range of temperatures and pH values, and on carbon and nitrogen amended media. N. gansuense was able to grow at 10-30 degrees C, but not at 5 degrees C, and slowly at 35 degrees C. The optimal temperature for both N. gansuense and N. coenophialum was 25 degrees C, but that of E. festucae was 20-25 degrees C. The optimal pH ranges for mycelial growth of N. gansuense, N. coenophialum and E. festucae were 5-9, 5-9 and 5-7, respectively. The Neotyphodium and Epichloë endophytes varied in their ability to grow on media containing different carbon and nitrogen nutrients. The preference of N. gansuense for carbon source was sucrose>glucose, lactose, sorbitol, inulin, maltose, mannitol, starch, fructose>xylose. Growth of all three endophytes tested was significantly improved by peptone, tryptone, casein, yeast extract and l-proline. Yeast extract, peptone, casein, tryptone, l-proline, potassium nitrate, ammonium oxalic acid and l-leucine significantly improved growth of N. gansuense. However, ammonium nitrite was not utilized at all by any tested endophyte. N. gansuense grew significantly better on potato dextrose agar (PDA) and oat meal agar (OMA) than on corn meal agar (CMA) and drunken-horse-grass agar (DA), and most slowly on water agar (WA) and saltwater nutrient agar (SNA).

Ethylene production in relation to nitrogen metabolism in Saccharomyces cerevisiae.

PubMed

Johansson, Nina; Persson, Karl O; Quehl, Paul; Norbeck, Joakim; Larsson, Christer

2014-11-01

We have previously shown that ethylene production in Saccharomyces cerevisiae expressing the ethylene-forming enzyme (EFE) from Pseudomonas syringae is strongly influenced by variations in the mode of cultivation as well as the choice of nitrogen source. Here, we have studied the influence of nitrogen metabolism on the production of ethylene further. Using ammonium, glutamate, glutamate/arginine, and arginine as nitrogen sources, it was found that glutamate (with or without arginine) correlates with a high ethylene production, most likely linked to an observed increase in 2-oxoglutarate levels. Arginine as a sole nitrogen source caused a reduced ethylene production. A reduction of arginine levels, accomplished using an arginine auxotrophic ARG4-deletion strain in the presence of limiting amounts of arginine or through CAR1 overexpression, did however not correlate with an increased ethylene production. As expected, arginine was necessary for ethylene production as ethylene production in the ARG4-deletion strain ceased at the time when arginine was depleted. In conclusion, our data suggest that high levels of 2-oxoglutarate and a limited amount of arginine are required for successful ethylene production in yeast. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

A Survey of Information Source Preferences of Parents of Individuals with Autism Spectrum Disorder.

PubMed

Gibson, Amelia N; Kaplan, Samantha; Vardell, Emily

2017-07-01

For parents of children with an Autism spectrum disorder (ASD), high quality, easily accessible information and a strong peer network can be the key to raising a happy, healthy child, and maintaining family well-being and emotional resilience. This article reports the findings of an anonymous survey examining the information source preferences for 935 parents of individuals with ASDs in North Carolina. Data indicates that parents show similar information seeking patterns across the age spectrum, that availability of information (as indicated by overall information source selection) decrease as children age. It also shows that parents rely heavily on local sources of information, preferring them to nonlocal sources (such as the internet) for many types of information.

26 CFR 1.58-7 - Tax preferences attributable to foreign sources; preferences other than capital gains and stock...

Code of Federal Regulations, 2012 CFR

2012-04-01

... Germany Total Investment income from sources within $150,000 $120,000 $180,000 $450,000 Investment... per-country foreign tax credit limitation, his excess investment interest from France and Germany... this subparagraph, treated as deductions attributable to income from sources within Germany. Example 2...

26 CFR 1.58-7 - Tax preferences attributable to foreign sources; preferences other than capital gains and stock...

Code of Federal Regulations, 2013 CFR

2013-04-01

... Germany Total Investment income from sources within $150,000 $120,000 $180,000 $450,000 Investment... per-country foreign tax credit limitation, his excess investment interest from France and Germany... this subparagraph, treated as deductions attributable to income from sources within Germany. Example 2...

26 CFR 1.58-7 - Tax preferences attributable to foreign sources; preferences other than capital gains and stock...

Code of Federal Regulations, 2011 CFR

2011-04-01

... Germany Total Investment income from sources within $150,000 $120,000 $180,000 $450,000 Investment... per-country foreign tax credit limitation, his excess investment interest from France and Germany... this subparagraph, treated as deductions attributable to income from sources within Germany. Example 2...

26 CFR 1.58-7 - Tax preferences attributable to foreign sources; preferences other than capital gains and stock...

Code of Federal Regulations, 2014 CFR

2014-04-01

... Germany Total Investment income from sources within $150,000 $120,000 $180,000 $450,000 Investment... per-country foreign tax credit limitation, his excess investment interest from France and Germany... this subparagraph, treated as deductions attributable to income from sources within Germany. Example 2...

Preferred Information Sources of High School Students for Community Colleges and Universities

ERIC Educational Resources Information Center

Goff, Brent; Patino, Vanessa; Jackson, Gary

2004-01-01

To effectively communicate with potential students, it is important to utilize their preferred information sources. Survey data were gathered from 716 high school students who planned to attend college. There were communication source differences based on race and intent to attend two-year vs. four-year institutions. Important information sources…

Modeling Historical and Projected Future Atmospheric Nitrogen Loading to the Chesapeake Bay Watershed

EPA Science Inventory

Land use and climate change are expected to alter key processes in the Chesapeake Bay watershed and can potentially exacerbate the impact of excess nitrogen. Atmospheric sources are one of the largest loadings of nitrogen to the Chesapeake Bay watershed. In this study, we explore...

Linking landscape characteristics and stream nitrogen in the Oregon Coast Range: Empirical modeling of water quality monitoring data

EPA Science Inventory

Background sources of nitrogen (N) provide a challenge for setting stream nutrient criteria in the Pacific Northwest US. Red alder (Alnus rubra), an early successional nitrogen fixing tree, and sea salt inputs can strongly influence stream N concentrations observed in individual...

TECHNOLOGY INNOVATIONS AND EXPERIENCE CURVES FOR NITROGEN OXIDES CONTROL TECHNOLOGIES

EPA Science Inventory

This paper reviews the regulatory history for nitrogen oxides (NO_X) pollutant emissions from stationary sources, primarily in coal-fired power plants. Nitrogen dioxide (NO₂) is one of the six criteria pollutants regulated by the 1970 Clean Air Act where Nati...

Effects of biochar amendment and fertilizer sources on serrano chili pepper yield, uptake, and nitrogen fate

USDA-ARS?s Scientific Manuscript database

Efficient nitrogen (N) management strategies are a key approach in addressing the increase of food demand and environmental protection. Failing to achieve adequate nitrogen use efficiency (NUE) in agricultural systems can cause damaging outcomes including degradative water quality, increase in green...

Fluidizing a mixture of particulate coal and char

DOEpatents

Green, Norman W.

1979-08-07

Method of mixing particulate materials comprising contacting a primary source and a secondary source thereof whereby resulting mixture ensues; preferably at least one of the two sources has enough motion to insure good mixing and the particulate materials may be heat treated if desired. Apparatus for such mixing comprising an inlet for a primary source, a reactor communicating therewith, a feeding means for supplying a secondary source to the reactor, and an inlet for the secondary source. Feeding means is preferably adapted to supply fluidized materials.

Mixing method and apparatus

DOEpatents

Green, Norman W.

1982-06-15

Method of mixing particulate materials comprising contacting a primary source and a secondary source thereof whereby resulting mixture ensues; preferably at least one of the two sources has enough motion to insure good mixing and the particulate materials may be heat treated if desired. Apparatus for such mixing comprising an inlet for a primary source, a reactor communicating therewith, a feeding means for supplying a secondary source to the reactor, and an inlet for the secondary source. Feeding means is preferably adapted to supply fluidized materials.

Kinetic models for nitrogen inhibition in ANAMMOX and nitrification process on deammonification system at room temperature

USDA-ARS?s Scientific Manuscript database

The performance of the deammonification process depends on the microbial activity of ammonia oxidizing bacteria (AOB) and ANAMMOX bacteria. These autotrophic organisms have different preferences for substrate, operating conditions and some external factors that may cause inhibition or imbalance of t...

Influence of carbon and nitrogen source on production of volatile fragrance and flavour metabolites by the yeast Kluyveromyces marxianus.

PubMed

Gethins, Loughlin; Guneser, Onur; Demirkol, Aslı; Rea, Mary C; Stanton, Catherine; Ross, R Paul; Yuceer, Yonca; Morrissey, John P

2015-01-01

The yeast Kluyveromyces marxianus produces a range of volatile molecules with applications as fragrances or flavours. The purpose of this study was to establish how nutritional conditions influence the production of these metabolites. Four strains were grown on synthetic media, using a variety of carbon and nitrogen sources and volatile metabolites analysed using gas chromatography-mass spectrometry (GC-MS). The nitrogen source had pronounced effects on metabolite production: levels of the fusel alcohols 2-phenylethanol and isoamyl alcohol were highest when yeast extract was the nitrogen source, and ammonium had a strong repressing effect on production of 2-phenylethyl acetate. In contrast, the nitrogen source did not affect production of isoamyl acetate or ethyl acetate, indicating that more than one alcohol acetyl transferase activity is present in K. marxianus. Production of all acetate esters was low when cells were growing on lactose (as opposed to glucose or fructose), with a lower intracellular pool of acetyl CoA being one explanation for this observation. Bioinformatic and phylogenetic analysis of the known yeast alcohol acetyl transferases ATF1 and ATF2 suggests that the ancestral protein Atf2p may not be involved in synthesis of volatile acetate esters in K. marxianus, and raises interesting questions as to what other genes encode this activity in non-Saccharomyces yeasts. Identification of all the genes involved in ester synthesis will be important for development of the K. marxianus platform for flavour and fragrance production. Copyright © 2014 John Wiley & Sons, Ltd.

Dynamic SPARROW Modeling of Nitrogen Flux with Climate and MODIS Vegetation Indices as Drivers

NASA Astrophysics Data System (ADS)

Smith, R. A.; Brakebill, J.; Schwarz, G.; Alexander, R. B.; Hirsch, R. M.; Nolin, A. W.; Macauley, M.; Zhang, Q.; Shih, J.; Wang, W.; Sproles, E.

2011-12-01

SPARROW models are widely used to identify and quantify the sources of contaminants in watersheds and to predict their flux and concentration at specified locations downstream. Conventional SPARROW models are statistically calibrated and describe the average relationship between sources and stream conditions based on long-term water quality monitoring data and spatially-referenced explanatory information. But many watershed management issues stem from intra- and inter-annual changes in contaminant sources, hydrologic forcing, or other environmental conditions which cause a temporary imbalance between inputs and stream water quality. Dynamic behavior of the system relating to changes in watershed storage and processing then becomes important. In this study, we describe a dynamically calibrated SPARROW model of total nitrogen flux in the Potomac River Basin based on seasonal water quality and watershed input data for 80 monitoring stations over the period 2000 to 2008. One challenge in dynamic modeling of reactive nitrogen is obtaining frequently-reported, spatially-detailed input data on the phenology of agricultural production and terrestrial vegetation. In this NASA-funded research, we use the Enhanced Vegetation Index (EVI) and gross primary productivity data from the Terra Satellite-borne MODIS sensor to parameterize seasonal uptake and release of nitrogen. The spatial reference frame of the model is a 16,000-reach, 1:100,000-scale stream network, and the computational time step is seasonal. Precipitation and temperature data are from PRISM. The model formulation allows for separate storage compartments for nonpoint sources including fertilized cropland, pasture, urban land, and atmospheric deposition. Removal of nitrogen from watershed storage to stream channels and to "permanent" sinks (deep groundwater and the atmosphere) occur as parallel first-order processes. We use the model to explore an important issue in nutrient management in the Potomac and other basins: the long-term response of total nitrogen flux to changing climate. We model the nitrogen flux response to projected seasonal and inter-annual changes in temperature and precipitation, but under current seasonal nitrogen inputs, as indicated by MODIS measures of productivity. Under these constant inter-annual inputs, changing temperature and precipitation is predicted to lead to flux changes as temporary basin stores of nitrogen either grow or shrink due to changing relative rates of nitrogen removal to the atmosphere and release to streams.

Effect of carbon source type on intracellular stored polymers during endogenous denitritation (ED) treating landfill leachate.

PubMed

Miao, Lei; Wang, Shuying; Li, Baikun; Cao, Tianhao; Zhang, Fangzhai; Wang, Zhong; Peng, Yongzhen

2016-09-01

Glycogen accumulating organisms (GAOs) capable of storing organic compounds as polyhydroxyalkanoate (PHA) have been used for endogenous denitritation (ED), but the effect of carbon sources type on nitrogen removal performance of GAOs treating landfill leachate is unclear. In this study, a successful ED system treating landfill leachate (COD/NH4(+)-N (C/N): 4) without external carbon source addition was applied. The mature leachate with C/N of 1 was used as the feeding base solution, with acetate, propionate, and glucose examined as the carbon sources, and their effects on yields and compositions of PHA produced by GAOs were determined and associated with nitrogen removal performance. In the case of sole carbon source, acetate was much easier to be stored than propionate and glucose, which led to a higher nitrogen removal efficiency. Glucose had the lowest amount of PHA storage and led to the lowest performance. In the case of composite carbon sources (two scenarios: acetate + propionate; acetate + propionate + glucose), GAOs stored sufficient PHA and exhibited similar nitrogen removal efficiencies. Moreover, type of carbon source influenced the compositions of PHA. The polyhydroxybutyrate (PHB) fraction in PHA was far more than polyhydroxyvalerate (PHV) in all tests. PHV was synthesized only when acetate existed in carbon source. The microbial diversity analysis revealed that Proteobacteria was the most abundant phylum. Among the 108 genera detected in this ED system, the genera responsible for denitritation were Thauera, Paracoccus, Ottowia and Comamonadaceae_unclassified, accounting for 46.21% of total bacteria. Especially, Paracoccus and Comamonadaceae_unclassified transformed the carbon source into PHA for denitritation, and carried out endogenous denitritation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intensive straw harvesting, fertilization, and fertilizer source affect nitrogen mineralization and soil labile carbon of a loblolly pine plantation

Treesearch

K. Ellum; H.O. Liechty; M.A. Blazier

2013-01-01

Straw harvesting can supplement traditional revenues generated by loblolly pine (Pinus taeda L.) plantation management. However, repeated raking may alter soil properties and nutrition. In northcentral Louisiana, a study was conducted to evaluate the long-term effects of intensive straw raking and fertilizer source (inorganic or organic) on nitrogen...

Effect of delayed wrapping and wrapping source on nitrogen balance and blood urea nitrogen in gestating sheep offered alfalfa silage

USDA-ARS?s Scientific Manuscript database

Exposing ensiled forage to oxygen can result in DM deterioration and reduce silage intake by animals. This study was conducted to investigate the effects of 2 different wrapping sources and time intervals between baling and wrapping on N balance and blood urea N in gestating sheep offered alfalfa si...

Atmospheric ammonia measurements at low concentration sites in the northeastern USA: implications for total nitrogen deposition and comparison with CMAQ estimates

EPA Science Inventory

We evaluated the relative importance of dry deposition of ammonia (NH3) gas at several headwater areas of the Susquehanna River, the largest single source of nitrogen pollution to Chesapeake Bay, including three that are remote from major sources of NH3 emissions (CTH, ARN, and K...

Energetic Charged Particle Component or the NO(y) Budget of the Polar Middle Atmosphere

NASA Technical Reports Server (NTRS)

Vitt, F. M.; Jackman, C. H.

1999-01-01

Analysis of nitrates measured in polar ice cap snow at a high resolution shows large variations in the nitrates. It has been shown that the nitrate signal may contain a signature of solar activity [Zeller and Dreschhoff, 19951. Reactive odd nitrogen production associated with solar particle events (SPEs) and auroral activity may be a source of some of the nitrate anomalies observed in the polar ice caps. Periods of large SPEs can lead to a production of polar atmospheric odd nitrogen in excess of the ambient sources in the polar stratosphere and mesosphere, and may leave a large nitrate signal stratified in the polar ice cap. Auroral electrons and photoelectrons produce odd nitrogen in the thermosphere, some of which may be transported to the polar (>50 degrees) mesosphere and stratosphere. Sources of odd nitrogen in the polar middle atmosphere associated with SPEs, galactic cosmic rays, and auroral electron precipitation have been quantified. The relative contributions by the energetic particles sources to the Noy budget of the polar middle atmosphere (from tropopause to 50 km, from 50 degrees to 90 degrees latitude) are compared with the nitrates observed in the polar ice sheets.

L-Arogenate is a chemoattractant which can be utilized as the sole source of carbon and nitrogen by Pseudomonas aeruginosa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischer, R.S.; Song, Jian; Gu, Wei

L-Arogenate is a commonplace amino acid in nature in consideration of its role as a ubiquitous precursor of L-phenylalanine and/or L-tyrosine. However, the questions of whether it serves as a chemoattractant molecule and whether it can serve as a substrate for catabolism have never been studied. We found that Pseudomonas aeruginosa recognizes L-arogenate as a chemoattractant molecule which can be utilized as a source of both carbon and nitrogen. Mutants lacking expression of either cyclohexadienyl dehydratase or phenylalanine hydroxylase exhibited highly reduced growth rates when utilizing L-arogenate as a nitrogen source. Utilization of L-arogenate as a source of either carbonmore » or nitrogen was dependent upon {sub S}{sup 54}, as revealed by the use of an rpoN null mutant. The evidence suggests that catabolism of L-arogenate proceeds via alternative pathways which converge at 4-hydroxyphenylpyruvate. In one pathway, prephenate formed in the periplasm by deamination of L-arogenate is converted to 4-hydroxyphenylpyruvate by cyclohexadienyl dehydrogenase. The second route depends upon the sequential action of periplasmic cyclohexadienyl dehydratase, phenylalanine hydroxylase, and aromatic aminotransferase. 32 refs., 5 figs., 4 tabs.« less

Production of citrinin-free Monascus pigments by submerged culture at low pH.

PubMed

Kang, Biyu; Zhang, Xuehong; Wu, Zhenqiang; Wang, Zhilong; Park, Sunghoon

2014-02-05

Microbial fermentation of citrinin-free Monascus pigments is of great interest to meet the demand of food safety. In the present work, the effect of various nitrogen sources, such as monosodium glutamate (MSG), cornmeal, (NH4)₂SO₄, and NaNO₃, on Monascus fermentation was examined under different initial pH conditions. The composition of Monascus pigments and the final pH of fermentation broth after Monascus fermentation were determined. It was found that nitrogen source was directly related to the final pH and the final pH regulated the composition of Monascus pigments and the biosynthesis of citrinin. Thus, an ideal nitrogen source can be selected to control the final pH and then the citrinin biosynthesis. Citrinin-free orange pigments were produced at extremely low initial pH in the medium with (NH4)₂SO₄ or MSG as nitrogen source. No citrinin biosynthesis at extremely low pH was further confirmed by extractive fermentation of intracellular pigments in the nonionic surfactant Triton X-100 micelle aqueous solution. This is the first report about the production of citrinin-free Monascus pigments at extremely low pH. Copyright © 2013 Elsevier Inc. All rights reserved.

N-Doped Graphene with Low Intrinsic Defect Densities via a Solid Source Doping Technique.

PubMed

Liu, Bo; Yang, Chia-Ming; Liu, Zhiwei; Lai, Chao-Sung

2017-09-30

N-doped graphene with low intrinsic defect densities was obtained by combining a solid source doping technique and chemical vapor deposition (CVD). The solid source for N-doping was embedded into the copper substrate by NH₃ plasma immersion. During the treatment, NH₃ plasma radicals not only flattened the Cu substrate such that the root-mean-square roughness value gradually decreased from 51.9 nm to 15.5 nm but also enhanced the nitrogen content in the Cu substrate. The smooth surface of copper enables good control of graphene growth and the decoupling of height fluctuations and ripple effects, which compensate for the Coulomb scattering by nitrogen incorporation. On the other hand, the nitrogen atoms on the pre-treated Cu surface enable nitrogen incorporation with low defect densities, causing less damage to the graphene structure during the process. Most incorporated nitrogen atoms are found in the pyrrolic configuration, with the nitrogen fraction ranging from 1.64% to 3.05%, while the samples exhibit low defect densities, as revealed by Raman spectroscopy. In the top-gated graphene transistor measurement, N-doped graphene exhibits n-type behavior, and the obtained carrier mobilities are greater than 1100 cm²·V -1 ·s -1 . In this study, an efficient and minimally damaging n-doping approach was proposed for graphene nanoelectronic applications.

Magnitudes, nature, and effects of point and nonpoint discharges in the Chattahoochee River Basin, Atlanta to West Point Dam, Georgia

USGS Publications Warehouse

Stamer, J.K.; Cherry, Rodney N.; Faye, R.E.; Kleckner, R.L.

1979-01-01

During the period April 1975 to June 1978, the U.S. Geological Survey conducted a river-quality assessment of the Upper Chattahoochee River basin in Georgia. One objective of the study was to assess the magnitudes, nature, and effects of point and non-point discharges in the Chattahoochee River basin from Atlanta to the West Point Dam. On an average annual basis and during the storm period of March 1215, 1976, non-point-source loads for most constituents analyzed were larger than point-source loads at the Whitesburg station, located on the Chattahoochee River about 40 river miles downstream of Atlanta. Most of the non-point-source constituent loads in the Atlanta-to-Whitesburg reach were from urban areas. Average annual point-source discharges accounted for about 50 percent of the dissolved nitrogen, total nitrogen, and total phosphorus loads, and about 70 percent of the dissolved phosphorus loads at Whitesburg. During weekends, power generation at the upstream Buford Dam hydroelectric facility is minimal. Streamflow at the Atlanta station during dry-weather weekends is estimated to be about 1,200 ft3/s (cubic feet per second). Average daily dissolved-oxygen concentrations of less than 5.0 mg/L (milligrams per liter) occurred often in the river, about 20 river miles downstream from Atlanta during these periods from May to November. During a low-flow period, June 1-2, 1977, five municipal point sources contributed 63 percent of the ultimate biochemical oxygen demand, 97 percent of the ammonium nitrogen, 78 percent of the total nitrogen, and 90 percent of the total phosphorus loads at the Franklin station, at the upstream end of West Point Lake. Average daily concentrations of 13 mg/L of ultimate biochemical oxygen demand and 1.8 mg/L of ammonium nitrogen were observed about 2 river miles downstream from two of the municipal point sources. Carbonaceous and nitrogenous oxygen demands caused dissolved-oxygen concentrations between 4.1 and 5.0 mg/L to occur in a 22-mile reach of the river downstream from Atlanta. Nitrogenous oxygen demands were greater than carbonaceous oxygen demands in the reach from river mile 303 to 271, and carbonaceous demands were greater from river mile 271 to 235. The heat load from the Atkinson-McDonough thermoelectric power-plants caused a decrease in the dissolved-oxygen concentrations of about 0.2 mg/L. During a critical low-flow period, a streamflow at Atlanta of about 1,800 ft3/s, with present (1977) point-source flows of 185 ft3/s containing concentrations of 45 mg/L of ultimate biochemical oxygen demand and 15 mg/L of ammonium nitrogen, results in a computed minimum dissolved-oxygen concentration of 4.7 mg/L in the river downstream from Atlanta. In the year 2000, a streamflow at Atlanta of about 1,800 ft3/s with point-source flows of 373 ft3/s containing concentrations of 45 mg/L of ultimate biochemical oxygen demand and 5.0 mg/L of ammonium nitrogen, will result in a computed minimum dissolved-oxygen concentration of 5.0 mg/L. A streamflow of about 1,050 ft3/s at Atlanta in the year 2000 will result in a dissolved-oxygen concentration of 5.0 mg/L if point-source flows contain concentrations of 15 mg/L of ultimate biochemical oxygen demand and 5.0 mg/L of ammonium nitrogen. Phytoplankton concentrations in West Point Lake, about 70 river miles downstream from Atlanta, could exceed 3 million cells per milliliter during extended low-flow periods in the summer with present point- and non-point-source nitrogen and phosphorus loads. In the year 2000, phytoplankton concentrations in West Point Lake are not likely to exceed 700,000 cells per milliliter during extended low-flow periods in the summer, if phosphorus concentrations do not exceed 1.0 mg/L in point-source discharges.

DNA microarray analysis of the cyanotroph Pseudomonas pseudoalcaligenes CECT5344 in response to nitrogen starvation, cyanide and a jewelry wastewater.

PubMed

Luque-Almagro, V M; Escribano, M P; Manso, I; Sáez, L P; Cabello, P; Moreno-Vivián, C; Roldán, M D

2015-11-20

Pseudomonas pseudoalcaligenes CECT5344 is an alkaliphilic bacterium that can use cyanide as nitrogen source for growth, becoming a suitable candidate to be applied in biological treatment of cyanide-containing wastewaters. The assessment of the whole genome sequence of the strain CECT5344 has allowed the generation of DNA microarrays to analyze the response to different nitrogen sources. The mRNA of P. pseudoalcaligenes CECT5344 cells grown under nitrogen limiting conditions showed considerable changes when compared against the transcripts from cells grown with ammonium; up-regulated genes were, among others, the glnK gene encoding the nitrogen regulatory protein PII, the two-component ntrBC system involved in global nitrogen regulation, and the ammonium transporter-encoding amtB gene. The protein coding transcripts of P. pseudoalcaligenes CECT5344 cells grown with sodium cyanide or an industrial jewelry wastewater that contains high concentration of cyanide and metals like iron, copper and zinc, were also compared against the transcripts of cells grown with ammonium as nitrogen source. This analysis revealed the induction by cyanide and the cyanide-rich wastewater of four nitrilase-encoding genes, including the nitC gene that is essential for cyanide assimilation, the cyanase cynS gene involved in cyanate assimilation, the cioAB genes required for the cyanide-insensitive respiration, and the ahpC gene coding for an alkyl-hydroperoxide reductase that could be related with iron homeostasis and oxidative stress. The nitC and cynS genes were also induced in cells grown under nitrogen starvation conditions. In cells grown with the jewelry wastewater, a malate quinone:oxidoreductase mqoB gene and several genes coding for metal extrusion systems were specifically induced. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Sources and behaviour of nitrogen compounds in the shallow groundwater of agricultural areas (Poyang Lake basin, China)

NASA Astrophysics Data System (ADS)

Soldatova, Evgeniya; Guseva, Natalia; Sun, Zhanxue; Bychinsky, Valeriy; Boeckx, Pascal; Gao, Bai

2017-07-01

Nitrogen contamination of natural water is a typical problem for various territories throughout the world. One of the regions exposed to nitrogen pollution is located in the Poyang Lake basin. As a result of agricultural activity and dense population, the shallow groundwater of this area is characterised by a high concentration of nitrogen compounds, primarily NO3-, with the concentration varying from 0.1 mg/L to 206 mg/L. Locally, high ammonium content occurs in the shallow groundwater with low reduction potential Eh (< 100 mV). However, in general, the shallow groundwater of the Poyang Lake basin has Eh > 100 mV. To identify sources of nitrogen species and the factors that determine their behaviour, the dual stable isotope approach (δ15N and δ18О) and physical-chemical modelling were applied. Actual data were collected by sampling shallow groundwater from domestic water supply wells around the lake. The δ18О values from - 4.1‰ to 13.9‰ with an average value of 5.3 permille indicate a significant influence of nitrification on nitrogen balance. The enrichment of nitrate with the 15N isotope indicates that manure and domestic sewage are the principal sources of nitrogen compounds. Inorganic nitrogen speciation and thermodynamic calculations demonstrate the high stability of nitrate in the studied groundwater. Computer simulation and field observations indicate the reducing conditions formed under joint effects of anthropogenic factors and appropriate natural conditions, such as the low-level topography in which decreased water exchange rate can occur. The simulation also demonstrates the growth in pH of the groundwater as a consequence of fertilisation, which, in turn, conduced to the clay mineral formation at lower concentrations of aqueous clay-forming components than the ones under the natural conditions.

DFT Insights into the Competitive Adsorption of Sulfur- and Nitrogen-Containing Compounds and Hydrocarbons on Co-Promoted Molybdenum Sulfide Catalysts

DOE PAGES

Rangarajan, Srinivas; Mavrikakis, Manos

2016-04-07

The adsorption of 20 nitrogen-/sulfur-containing and hydrocarbon compounds on the sulfur edge of cobalt-promoted molybdenum sulfide (CoMoS) catalyst was studied using density functional theory, accounting for van der Waals interactions, to elicit comparative structure–property trends across different classes of molecules relevant to hydrotreating. Unhindered organosulfur compounds preferentially adsorb on a “CUS-like” site formed by the dimerization of two neighboring sulfur atoms on the edge to create a vacancy. Nitrogen-containing compounds and 4,6-dimethyldibenzothiophene, however, prefer the brim sites. Binding energy trends indicate that nitrogen-containing compounds will inhibit hydrodesulfurization on the brim sites and, relatively weakly, on the CUS-like sites. Edge vacanciesmore » are,thus, likely to be essential for hydrodesulfurization of unhindered organosulfur compounds. Furthermore, van der Waals forces contribute significantly to the binding energy of compounds (up to 1.0 eV for large compounds such as alkyl-substituted acridines) on CoMoS.« less

Residents’ Preferences for Household Kitchen Waste Source Separation Services in Beijing: A Choice Experiment Approach

PubMed Central

Yuan, Yalin; Yabe, Mitsuyasu

2014-01-01

A source separation program for household kitchen waste has been in place in Beijing since 2010. However, the participation rate of residents is far from satisfactory. This study was carried out to identify residents’ preferences based on an improved management strategy for household kitchen waste source separation. We determine the preferences of residents in an ad hoc sample, according to their age level, for source separation services and their marginal willingness to accept compensation for the service attributes. We used a multinomial logit model to analyze the data, collected from 394 residents in Haidian and Dongcheng districts of Beijing City through a choice experiment. The results show there are differences of preferences on the services attributes between young, middle, and old age residents. Low compensation is not a major factor to promote young and middle age residents accept the proposed separation services. However, on average, most of them prefer services with frequent, evening, plastic bag attributes and without instructor. This study indicates that there is a potential for local government to improve the current separation services accordingly. PMID:25546279

Genetic and physiological relationships between L-asparaginase I and asparaginase II in Saccharomyces cerevisiae.

PubMed Central

Jones, G E

1977-01-01

The cistron that codes for L-asparaginase I in Saccharomyces cerevisiae (aspl) is not genetically linked to either of the cistrons coding for expression of asparaginase II (asp2 and asp3). Cells containing different combinations of theses enzymes grow at different rates in media in which L-asparagine or D-asparagine is the only source of nitrogen for cell replication. Cells lacking L-asparaginase I but possessing asparaginase II grow more rapidly in medium containing D-asparagine as a nitrogen source than cells containing both enzymes, even though D-asparagine is not a substrate of L-asparaginase I. These results indicate that L-asparaginase I and asparaginase II interact in some way to regulate the utilization of asparagine as a nitrogen source for cell growth. PMID:323221

[Influence of the type of dietary carbohydrate on the use of 2 protein sources by rainbow trout reared at 8 or 18C].

PubMed

Aguirre, P; Medale, F; Kaushik, S J

1995-01-01

The effect of the type of dietary starch (gelatinized vs native) on the biological value of fish meal (FP) and fish soluble protein concentrate (CPSP) was studied through the nitrogen balance in rainbow trout (Oncorhynchus mykiss) reared for 3 weeks at 2 water temperatures: 8 or 18 degrees C. The protein sources were included in diets at a level of 60% and gelatinized or raw starch at a level of 30%. Gelatinized starch improved the biological value of FP and CPSP by reducing the metabolic nitrogen losses. Trout fed the diet with CPSP had a higher nitrogen excretion than those fed the diet with FP. The biological value of both protein sources was unaffected by water temperature.

Adding a nitrogen footprint to Colorado State University’s sustainability plan

USGS Publications Warehouse

Kimiecik, Jacob; Baron, Jill S.; Weinmann, Timothy; Taylor, Emily

2017-01-01

As a large land grant university with more than 32,000 students, Colorado State University has both on-campus non-agricultural and agricultural sources of nitrogen (N) released to the environment. We used the Nitrogen Footprint Tool to estimate the amount of N released from different sectors of the university for the CSU 2014 academic year. The largest on campus sources were food production, utilities (heating, cooling, electricity), and research animals. The total on-campus N footprint in 2014 was 287 metric tons. This value was equivalent to the nitrogen footprint of agricultural experiment stations and other agricultural facilities, whose nitrogen footprint was 273 metric tons. CSU has opportunities to reduce its on-campus footprint through educational programs promoting low-meat diets and commuting by bicycle or bus. There is also an opportunity to advance ideas of agricultural best management practices, including precision farming and better livestock management. This article describes the planned and ongoing efforts to educate CSU about how societal activities release nitrogen to the environment, contributing to global change. It offers personal and institutional options for taking action, which would ultimately reduce CSU’s excess reactive nitrogen loss to the environment. The N-footprint for CSU, including scenarios of possible future nitrogen reductions, is also discussed.

Effects of land-use patterns on in-stream nitrogen in a highly-polluted river basin in Northeast China.

PubMed

Bu, Hongmei; Zhang, Yuan; Meng, Wei; Song, Xianfang

2016-05-15

This study investigated the effects of land-use patterns on nitrogen pollution in the Haicheng River basin in Northeast China during 2010 by conducting statistical and spatial analyses and by analyzing the isotopic composition of nitrate. Correlation and stepwise regressions indicated that land-use types and landscape metrics were correlated well with most river nitrogen variables and significantly predicted them during different sampling seasons. Built-up land use and shape metrics dominated in predicting nitrogen variables over seasons. According to the isotopic compositions of river nitrate in different zones, the nitrogen sources of the river principally originated from synthetic fertilizer, domestic sewage/manure, soil organic matter, and atmospheric deposition. Isotope mixing models indicated that source contributions of river nitrogen significantly varied from forested headwaters to densely populated towns of the river basin. Domestic sewage/manure was a major contributor to river nitrogen with the proportions of 76.4 ± 6.0% and 62.8 ± 2.1% in residence and farmland-residence zones, respectively. This research suggested that regulating built-up land uses and reducing discharges of domestic sewage and industrial wastewater would be effective methods for river nitrogen control. Copyright © 2016 Elsevier B.V. All rights reserved.

Sources of reactive nitrogen in marine aerosol over the Northwest Pacific Ocean in spring

NASA Astrophysics Data System (ADS)

Luo, Li; Kao, Shuh-Ji; Bao, Hongyan; Xiao, Huayun; Xiao, Hongwei; Yao, Xiaohong; Gao, Huiwang; Li, Jiawei; Lu, Yangyang

2018-05-01

Atmospheric deposition of long-range transport of anthropogenic reactive nitrogen (Nr, mainly comprised of NHx, NOy and water-soluble organic nitrogen, WSON) from continents may have profound impact on marine biogeochemistry. In addition, surface ocean dissolved organic nitrogen (DON) may also contribute to aerosol WSON in the overlying atmosphere. Despite the importance of off-continent dispersion and Nr interactions at the atmosphere-ocean boundary, our knowledge of the sources of various nitrogen species in the atmosphere over the open ocean remains limited due to insufficient observations. We conducted two cruises in the spring of 2014 and 2015 from the coast of China through the East China seas (ECSs, i.e. the Yellow Sea and East China Sea) to the open ocean (i.e. the Northwest Pacific Ocean, NWPO). Concentrations of water-soluble total nitrogen (WSTN), NO3- and NH4+, as well as the δ15N of WSTN and NO3- in marine aerosol, were measured during both cruises. In the spring of 2015, we also analysed the concentrations and δ15N of NO3- and the DON of surface seawater (SSW; at a depth of 5 m) along the cruise track. Aerosol NO3-, NH4+ and WSON decreased logarithmically (1-2 orders of magnitude) with distance from the shore, reflecting strong anthropogenic emission sources of NO3-, NH4+ and WSON in China. Average aerosol NO3- and NH4+ concentrations were significantly higher in 2014 (even in the remote NWOP) than in 2015 due to the stronger wind field in 2014, underscoring the role of the Asian winter monsoon in the seaward transport of anthropogenic NO3- and NH4+. However, the background aerosol WSON over the NWPO in 2015 (13.3 ± 8.5 nmol m-3) was similar to that in 2014 (12.2 ± 6.3 nmol m-3), suggesting an additional non-anthropogenic WSON source in the open ocean. Obviously, marine DON emissions should be considered in model and field assessments of net atmospheric WSON deposition in the open ocean. This study contributes information on parallel isotopic marine DON composition and aerosol Nr datasets, but more research is required to explore complex Nr sources and deposition processes in order to advance our understanding of anthropogenic influences on the marine nitrogen cycle and nitrogen exchange at land-ocean and atmosphere-ocean interfaces.

On-line estimation of O2 production, CO2 uptake, and growth kinetics of microalgal cultures in a gas-tight photobioreactor

PubMed Central

Riisgård, Frederik Kier; Gunther, William Stuart; Lønsmann Iversen, Jens Jørgen

2006-01-01

Growth of the green algae Chlamydomonas reinhardtii and Chlorella sp. in batch cultures was investigated in a novel gas-tight photobioreactor, in which CO2, H2, and N2 were titrated into the gas phase to control medium pH, dissolved oxygen partial pressure, and headspace pressure, respectively. The exit gas from the reactor was circulated through a loop of tubing and re-introduced into the culture. CO2 uptake was estimated from the addition of CO2 as acidic titrant and O2 evolution was estimated from titration by H2, which was used to reduce O2 over a Pd catalyst. The photosynthetic quotient, PQ, was estimated as the ratio between O2 evolution and CO2 up-take rates. NH4+, NO2−, or NO3− was the final cell density limiting nutrient. Cultures of both algae were, in general, characterised by a nitrogen sufficient growth phase followed by a nitrogen depleted phase in which starch was the major product. The estimated PQ values were dependent on the level of oxidation of the nitrogen source. The PQ was 1 with NH4+ as the nitrogen source and 1.3 when NO3− was the nitrogen source. In cultures grown on all nitrogen sources, the PQ value approached 1 when the nitrogen source was depleted and starch synthesis became dominant, to further increase towards 1.3 over a period of 3–4 days. This latter increase in PQ, which was indicative of production of reduced compounds like lipids, correlated with a simultaneous increase in the degree of reduction of the biomass. When using the titrations of CO2 and H2 into the reactor headspace to estimate the up-take of CO2, the production of O2, and the PQ, the rate of biomass production could be followed, the stoichiometrical composition of the produced algal biomass could be estimated, and different growth phases could be identified. PMID:19396354

Alpine Warming induced Nitrogen Export from Green Lakes Valley, Colorado Front Range, USA

NASA Astrophysics Data System (ADS)

Barnes, R. T.; Williams, M. W.; Parman, J.

2012-12-01

Alpine ecosystems are particularly susceptible to disturbance due to their short growing seasons, sparse vegetation and thin soils. Atmospheric nitrogen deposition and warming temperatures currently affect Green Lakes Valley (GLV) within the Colorado Front Range. Research conducted within the alpine links chronic nitrogen inputs to a suite of ecological impacts, resulting in increased nitrate export. According to NADP records at the site, the atmospheric flux of nitrogen has decreased by 0.56 kg ha-1 yr-1 since 2000, due to a decrease in precipitation. Concurrent with this decrease, alpine nitrate yields have continued to increase; by 32% relative to the previous decade (1990-1999). In order to determine the source(s) of the sustained nitrate increases we utilized long term datasets to construct a mass balance model for four stream segments (glacier to subalpine) for nitrogen and weathering product constituents. We also compared geochemical fingerprints of various solute sources (glacial meltwater, thawing permafrost, snow, and stream water) to alpine stream water to determine if sources had changed over time. Long term trends indicate that in addition to increases in nitrate; sulfate, calcium, and silica have also increased over the same period. The geochemical composition of thawing permafrost (as indicated by rock glacial meltwater) suggests it is the source of these weathering products. Mass balance results indicate the high ammonium loads within glacial meltwater are rapidly nitrified, contributing approximately 0.45 kg yr-1 to the NO3- flux within the upper reaches of the watershed. The sustained export of these solutes during dry, summer months is likely facilitated by thawing cryosphere providing hydraulic connectivity late into the growing season. In a neighboring catchment, lacking permafrost and glacial features, there were no long term weathering or nitrogen solute trends; providing further evidence that the changes in alpine chemistry in GLV are likely due to cryospheric thaw exposing soils to biological and geochemical processes. These findings suggest that efforts to reduce nitrogen deposition loads may not improve water quality, as thawing cryosphere associated with climate change may affect alpine nitrate concentrations as much, or more than atmospheric deposition trends.

Regulation of nitrogen uptake and assimilation: Effects of nitrogen source and root-zone and aerial environment on growth and productivity of soybean

NASA Technical Reports Server (NTRS)

Raper, C. David, Jr.

1994-01-01

The interdependence of root and shoot growth produces a functional equilibrium as described in quantitative terms by numerous authors. It was noted that bean seedlings grown in a constant environment tended to have a constant distribution pattern of dry matter between roots and leaves characteristic of the set of environmental conditions. Disturbing equilibrium resulted in a change in relative growth of roots and leaves until the original ratio was restored. To define a physiological basis for regulation of nitrogen uptake within the balance between root and shoot activities, the authors combined a partioning scheme and a utilization priority assumption in which: (1) all carbon enters the plant through photosynthesis in leaves and all nitrogen enters the plant through active uptake by roots, (2) nitrogen uptake by roots and secretion into the xylem for transport to the shoots are active processes, (3) availability of exogenous nitrogen determines concentration of soluble carbohydrates within the roots, (4) leaves are a source and a sink for carbohydrates, and (5) the requirement for nitrogen by leaf growth is proportionally greater during initiation and early expansion than during later expansion.

Evidence for indigenous nitrogen in sedimentary and aeolian deposits from the Curiosity rover investigations at Gale crater, Mars

PubMed Central

Stern, Jennifer C.; Sutter, Brad; Freissinet, Caroline; Navarro-González, Rafael; McKay, Christopher P.; Archer, P. Douglas; Buch, Arnaud; Brunner, Anna E.; Coll, Patrice; Eigenbrode, Jennifer L.; Fairen, Alberto G.; Franz, Heather B.; Glavin, Daniel P.; Kashyap, Srishti; McAdam, Amy C.; Ming, Douglas W.; Steele, Andrew; Szopa, Cyril; Wray, James J.; Martín-Torres, F. Javier; Zorzano, Maria-Paz; Conrad, Pamela G.; Mahaffy, Paul R.; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Grotzinger, John; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; - Torres, F. Javier Martín; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d’Uston, Claude; Forni, Olivier; Gasnault, Olivier; Lasue, Jérémie; Lee, Qiu-Mei; Maurice, Sylvestre; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Dromart, Gilles; Robert, François; Sautter, Violaine; Le Mouélic, Stéphane; Mangold, Nicolas; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Wiens, Roger C.; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Vasavada, Ashwin R.; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Williams, Rebecca M. E.; Yingst, Aileen; Lewis, Kevin; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mueller-Mellin, Reinhold; Wimmer-Schweingruber, Robert; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

2015-01-01

The Sample Analysis at Mars (SAM) investigation on the Mars Science Laboratory (MSL) Curiosity rover has detected oxidized nitrogen-bearing compounds during pyrolysis of scooped aeolian sediments and drilled sedimentary deposits within Gale crater. Total N concentrations ranged from 20 to 250 nmol N per sample. After subtraction of known N sources in SAM, our results support the equivalent of 110–300 ppm of nitrate in the Rocknest (RN) aeolian samples, and 70–260 and 330–1,100 ppm nitrate in John Klein (JK) and Cumberland (CB) mudstone deposits, respectively. Discovery of indigenous martian nitrogen in Mars surface materials has important implications for habitability and, specifically, for the potential evolution of a nitrogen cycle at some point in martian history. The detection of nitrate in both wind-drifted fines (RN) and in mudstone (JK, CB) is likely a result of N2 fixation to nitrate generated by thermal shock from impact or volcanic plume lightning on ancient Mars. Fixed nitrogen could have facilitated the development of a primitive nitrogen cycle on the surface of ancient Mars, potentially providing a biochemically accessible source of nitrogen. PMID:25831544

Evidence for indigenous nitrogen in sedimentary and aeolian deposits from the Curiosity rover investigations at Gale crater, Mars.

PubMed

Stern, Jennifer C; Sutter, Brad; Freissinet, Caroline; Navarro-González, Rafael; McKay, Christopher P; Archer, P Douglas; Buch, Arnaud; Brunner, Anna E; Coll, Patrice; Eigenbrode, Jennifer L; Fairen, Alberto G; Franz, Heather B; Glavin, Daniel P; Kashyap, Srishti; McAdam, Amy C; Ming, Douglas W; Steele, Andrew; Szopa, Cyril; Wray, James J; Martín-Torres, F Javier; Zorzano, Maria-Paz; Conrad, Pamela G; Mahaffy, Paul R

2015-04-07

The Sample Analysis at Mars (SAM) investigation on the Mars Science Laboratory (MSL) Curiosity rover has detected oxidized nitrogen-bearing compounds during pyrolysis of scooped aeolian sediments and drilled sedimentary deposits within Gale crater. Total N concentrations ranged from 20 to 250 nmol N per sample. After subtraction of known N sources in SAM, our results support the equivalent of 110-300 ppm of nitrate in the Rocknest (RN) aeolian samples, and 70-260 and 330-1,100 ppm nitrate in John Klein (JK) and Cumberland (CB) mudstone deposits, respectively. Discovery of indigenous martian nitrogen in Mars surface materials has important implications for habitability and, specifically, for the potential evolution of a nitrogen cycle at some point in martian history. The detection of nitrate in both wind-drifted fines (RN) and in mudstone (JK, CB) is likely a result of N2 fixation to nitrate generated by thermal shock from impact or volcanic plume lightning on ancient Mars. Fixed nitrogen could have facilitated the development of a primitive nitrogen cycle on the surface of ancient Mars, potentially providing a biochemically accessible source of nitrogen.

40 CFR 412.37 - Additional measures.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Calculations showing the total nitrogen and phosphorus to be applied to each field, including sources other than manure, litter, or process wastewater; (8) Total amount of nitrogen and phosphorus actually...

40 CFR 412.37 - Additional measures.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Calculations showing the total nitrogen and phosphorus to be applied to each field, including sources other than manure, litter, or process wastewater; (8) Total amount of nitrogen and phosphorus actually...

A regional classification of the effectiveness of depressional wetlands at mitigating nitrogen transport to surface waters in the Northern Atlantic Coastal Plain

USGS Publications Warehouse

Ator, Scott W.; Denver, Judith M.; LaMotte, Andrew E.; Sekellick, Andrew J.

2013-01-01

Nitrogen from nonpoint sources contributes to eutrophication, hypoxia, and related ecological degradation in Atlantic Coastal Plain streams and adjacent coastal estuaries such as Chesapeake Bay and Pamlico Sound. Although denitrification in depressional (non-riparian) wetlands common to the Coastal Plain can be a significant landscape sink for nitrogen, the effectiveness of individual wetlands at removing nitrogen varies substantially due to varying hydrogeologic, geochemical, and other landscape conditions, which are often poorly or inconsistently mapped over large areas. A geographic model describing the spatial variability in the likely effectiveness of depressional wetlands in watershed uplands at mitigating nitrogen transport from nonpoint sources to surface waters was constructed for the Northern Atlantic Coastal Plain (NACP), from North Carolina through New Jersey. Geographic and statistical techniques were used to develop the model. Available medium-resolution (1:100,000-scale) stream hydrography was used to define 33,799 individual watershed catchments in the study area. Sixteen landscape metrics relevant to the occurrence of depressional wetlands and their effectiveness as nitrogen sinks were defined for each catchment, based primarily on available topographic and soils data. Cluster analysis was used to aggregate the 33,799 catchments into eight wetland landscape regions (WLRs) based on the value of three principal components computed for the 16 original landscape metrics. Significant differences in topography, soil, and land cover among the eight WLRs demonstrate the effectiveness of the clustering technique. Results were used to interpret the relative likelihood of depressional wetlands in each WLR and their likely effectiveness at mitigating nitrogen transport from upland source areas to surface waters. The potential effectiveness of depressional wetlands at mitigating nitrogen transport varies substantially over different parts of the NACP. Depressional wetlands are common in three WLRs covering 32 percent of the area, and have a relatively high potential to mitigate nitrogen transport from nonpoint sources. Conversely, 37 percent of the study area includes rolling hills with relatively high slope and relief, and little likelihood of depressional wetlands. The remainder of the Coastal Plain includes relatively flat watersheds with moderate to low relative likelihood of nitrogen mitigation. The delineation of WLRs in this model should be useful for targeting wetland conservation or restoration efforts, and for estimating the effects of depressional wetlands on the regional nitrogen budget, but should be considered in light of limitations and assumptions inherent in the model.

Root Ideotype Influences Nitrogen Transport and Assimilation in Maize

PubMed Central

Dechorgnat, Julie; Francis, Karen L.; Dhugga, Kanwarpal S.; Rafalski, J. A.; Tyerman, Stephen D.; Kaiser, Brent N.

2018-01-01

Maize (Zea mays, L.) yield is strongly influenced by external nitrogen inputs and their availability in the soil solution. Overuse of nitrogen-fertilizers can have detrimental ecological consequences through increased nitrogen pollution of water and the release of the potent greenhouse gas, nitrous oxide. To improve yield and overall nitrogen use efficiency (NUE), a deeper understanding of nitrogen uptake and utilization is required. This study examines the performance of two contrasting maize inbred lines, B73 and F44. F44 was selected in Florida on predominantly sandy acidic soils subject to nitrate leaching while B73 was selected in Iowa on rich mollisol soils. Transcriptional, enzymatic and nitrogen transport analytical tools were used to identify differences in their N absorption and utilization capabilities. Our results show that B73 and F44 differ significantly in their genetic, enzymatic, and biochemical root nitrogen transport and assimilatory pathways. The phenotypes show a strong genetic relationship linked to nitrogen form, where B73 showed a greater capacity for ammonium transport and assimilation whereas F44 preferred nitrate. The contrasting phenotypes are typified by differences in root system architecture (RSA) developed in the presence of both nitrate and ammonium. F44 crown roots were longer, had a higher surface area and volume with a greater lateral root number and density than B73. In contrast, B73 roots (primary, seminal, and crown) were more abundant but lacked the defining features of the F44 crown roots. An F1 hybrid between B73 and F44 mirrored the B73 nitrogen specificity and root architecture phenotypes, indicating complete dominance of the B73 inbred. This study highlights the important link between RSA and nitrogen management and why both variables need to be tested together when defining NUE improvements in any selection program. PMID:29740466

Selecting and Using Information Sources: Source Preferences and Information Pathways of Israeli Library and Information Science Students

ERIC Educational Resources Information Center

Bronstein, Jenny

2010-01-01

Introduction: The study investigated the source preference criteria of library and information science students for their academic and personal information needs. Method: The empirical study was based on two methods of data collection. Eighteen participants wrote a personal diary for four months in which they recorded search episodes and answered…

Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit

PubMed Central

2014-01-01

Background The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. Results We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Conclusions Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning. PMID:24708438

Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit.

PubMed

Hoefman, Sven; van der Ha, David; Boon, Nico; Vandamme, Peter; De Vos, Paul; Heylen, Kim

2014-04-04

The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning.

Nitrogen release from rock and soil under simulated field conditions

USGS Publications Warehouse

Holloway, J.M.; Dahlgren, R.A.; Casey, W.H.

2001-01-01

A laboratory study was performed to simulate field weathering and nitrogen release from bedrock in a setting where geologic nitrogen has been suspected to be a large local source of nitrate. Two rock types containing nitrogen, slate (1370 mg N kg-1) and greenstone (480 mg N kg-1), were used along with saprolite and BC horizon sand from soils derived from these rock types. The fresh rock and weathered material were used in batch reactors that were leached every 30 days over 6 months to simulate a single wet season. Nitrogen was released from rock and soil materials at rates between 10-20 and 10-19 mo1 N cm-2 s-1. Results from the laboratory dissolution experiments were compared to in situ soil solutions and available mineral nitrogen pools from the BC horizon of both soils. Concentrations of mineral nitrogen (NO3- + NH4+) in soil solutions reached the highest levels at the beginning of the rainy season and progressively decreased with increased leaching. This seasonal pattern was repeated for the available mineral nitrogen pool that was extracted using a KCl solution. Estimates based on these laboratory release rates bracket stream water NO3-N fluxes and changes in the available mineral nitrogen pool over the active leaching period. These results confirm that geologic nitrogen, when present, may be a large and reactive pool that may contribute as a non-point source of nitrate contamination to surface and ground waters. ?? 2001 Elsevier Science B.V. All rights reserved.

COMBUSTION AREA SOURCES: DATA SOURCES

EPA Science Inventory

The report identifies, documents, and evaluates data sources for stationary area source emissions, including solid waste and agricultural burning. Area source emissions of particulate matter, sulfur dioxide, oxides of nitrogen, reactive volatile organic compounds, and carbon mon...

Identifying organic nitrogen compounds in Rocky Mountain National Park aerosols

NASA Astrophysics Data System (ADS)

Beem, K. B.; Desyaterik, Y.; Ozel, M. Z.; Hamilton, J. F.; Collett, J. L.

2010-12-01

Nitrogen deposition is an important issue in Rocky Mountain National Park (RMNP). While inorganic nitrogen contributions to the ecosystems in this area have been studied, the sources of organic nitrogen are still largely unknown. To better understand the potential sources of organic nitrogen, filter samples were collected and analyzed for organic nitrogen species. Samples were collected in RMNP using a Thermo Fisher Scientific TSP (total suspended particulate) high-volume sampler with a PM2.5 impactor plate from April - November of 2008. The samples presented the opportunity to compare two different methods for identification of individual organic nitrogen species. The first type of analysis was performed with a comprehensive two dimensional gas chromatography (GCxGC) system using a nitrogen chemiluminescence detector (NCD). The filter samples were spiked with propanil in dichloromethane to use as an internal standard and were then extracted in water followed by solid phase extraction. The GCxGC system was comprised of a volatility based separation (DB5 column) followed by a polarity based separation (RXI-17 column). A NCD was used to specifically detect nitrogen compounds and remove the complex background matrix. Individual standards were used to identify peaks by comparing retention times. This method has the added benefit of an equimolar response for nitrogen so only a single calibration is needed for all species. In the second analysis, a portion of the same filter samples were extracted in DI water and analyzed with liquid chromatography coupled with mass spectroscopy (LC/MS). The separation was performed using a C18 column and a water-methanol gradient elution. Electrospray ionization into a time of flight mass spectrometer was used for detection. High accuracy mass measurement allowed unambiguous assignments of elemental composition of resulting ions. Positive and negative polarities were used since amines tend to show up in positive mode and nitrates in negative. The differences in the number of species and what species are identified between these two methods are important for planning future analyses of organic nitrogen compounds. In addition, these data provide new insight into the potential source of organic nitrogen in RMNP. Using the GCxGC method, 39 organic nitrogen species were detected and 20 were identified. Identified species include several types of amines and phenols. The LC/MS method identified several types of cresols, amines, and nitrates.

Parents' preferred child health information sources: implications for nursing practice.

PubMed

Keatinge, Diane

2006-01-01

To ascertain parents' preferences in sources of health information concerning their children's general health care needs, and caring for their children when they are sick. Exploratory/descriptive design. A telephone survey secured data for the study and qualitative content analysis and descriptive statistics were used for analysis. Part 2 of a larger study in which Part I evaluated parents' satisfaction with a paediatric telephone triage service. One hundred of the 101 parents who were recruited for Part 1 of the study participated in Part 2, an examination of parents' preferences in information sources relating to their child's health. Parents' preferences in child health information sources varied according to the perceived severity of their child's illness. Parents frequently selected more than one item on a list of health information sources provided. In a non-urgent situation when children were sick a total of 170 selections were made by parents, with 'telephone advice line' the source most frequently selected (58, 34%), followed by general practitioner (27, 15.8%). In an emergency situation the most frequently selected information source was again 'telephone advice line' (74, n=129, 57.4%), followed by 'other' (31, n=129, 24.3%) often identified as relating to dialing '000' (Australia's emergency services number). Finally, when parents required information about the general health care needs of their child, 'other' (most frequently identified as books) was selected on 40 (n=185, 21.6%) occasions, followed by child health clinic (35, n= 185, 18.9%). Parents prefer to receive information about the health care needs of their child from another person rather than a printed or audio-visual source.

The first nitrogen index app for mobile devices: using portable technology for smart agricultural management

USDA-ARS?s Scientific Manuscript database

Nitrogen fertilizer from organic and inorganic sources is used across the world’s agroecosystems. It contributes to higher yields and higher economic returns to farmers, and is essential for food security. However, when more is applied than necessary, significant amounts of nitrogen can exit the sy...

77 FR 39949 - Effective Date for the Water Quality Standards for the State of Florida's Lakes and Flowing Waters

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-06

... Florida may be interested in this rulemaking. Entities discharging nitrogen or phosphorus to lakes and..., such as nonpoint source contributors to nitrogen/phosphorus pollution in Florida's waters may be... numeric nutrient criteria in the form of total nitrogen, total phosphorus, nitrate+nitrite, and...

Carbon, nitrogen and pH regulate the production and activity of a polygalacturonase isozyme produced by Penicillium expansum

USDA-ARS?s Scientific Manuscript database

The influence of carbon, nitrogen and pH on polygalacturonase activity produced by Penicillium expansum were investigated. P. expansum mycelial growth was greatest on lyophilized fruit tissue and the highest PG activity occurred in apple pectin medium. Nitrogen source influenced PG activity and was ...

Ecosystem Services in Lakes of the Northeastern United States: Upstream Benefits from Estuarine Nitrogen Reduction Scenarios

EPA Science Inventory

Reduction of nitrogen inputs to estuaries can be achieved by the control of agricultural, atmospheric, and urban sources. We use the USGS MRB1 SPARROW model to estimate reductions necessary to reduce nitrogen loads to estuaries by 10%. If only agricultural inputs are reduced, ...

Ammonium stimulates nitrate reduction during simultaneous nitrification and denitrification process by Arthrobacter arilaitensis Y-10.

PubMed

He, Tengxia; Xie, Deti; Li, Zhenlun; Ni, Jiupai; Sun, Quan

2017-09-01

The ability of Arthrobacter arilaitensis Y-10 for nitrogen removal from simulated wastewater was studied. Results showed that ammonium was the best inorganic nitrogen for strain Y-10's cell growth, which could also promote nitrate reduction. Approximately 100.0% of ammonium was removed in the nitrogen removal experiments. The nitrate removal efficiency was 73.3% with nitrate as sole nitrogen source, and then the nitrate efficiency was increased to 85.3% and 100.0% with ammonium and nitrate (both about 5 or 100mg/L) as the mixed nitrogen sources. Nitrite accumulation was observed in presence of ammonium and nitrate. When the concentration of sole nitrite nitrogen was 10.31mg/L, the nitrite removal efficiency was 100.0%. Neither ammonium nor nitrate was accumulated during the whole experimental process. All experimental results indicated that A. arilaitensis Y-10 could remove ammonium, nitrate and nitrite at 15°C from wastewater, and could also perform simultaneous nitrification and denitrification under aerobic condition. Copyright © 2017. Published by Elsevier Ltd.

Simulating stream transport of nutrients in the eastern United States, 2002, using a spatially-referenced regression model and 1:100,000-scale hydrography

USGS Publications Warehouse

Hoos, Anne B.; Moore, Richard B.; Garcia, Ana Maria; Noe, Gregory B.; Terziotti, Silvia E.; Johnston, Craig M.; Dennis, Robin L.

2013-01-01

Existing Spatially Referenced Regression on Watershed attributes (SPARROW) nutrient models for the northeastern and southeastern regions of the United States were recalibrated to achieve a hydrographically consistent model with which to assess nutrient sources and stream transport and investigate specific management questions about the effects of wetlands and atmospheric deposition on nutrient transport. Recalibrated nitrogen models for the northeast and southeast were sufficiently similar to be merged into a single nitrogen model for the eastern United States. The atmospheric deposition source in the nitrogen model has been improved to account for individual components of atmospheric input, derived from emissions from agricultural manure, agricultural livestock, vehicles, power plants, other industry, and background sources. This accounting makes it possible to simulate the effects of altering an individual component of atmospheric deposition, such as nitrate emissions from vehicles or power plants. Regional differences in transport of phosphorus through wetlands and reservoirs were investigated and resulted in two distinct phosphorus models for the northeast and southeast. The recalibrated nitrogen and phosphorus models account explicitly for the influence of wetlands on regional-scale land-phase and aqueous-phase transport of nutrients and therefore allow comparison of the water-quality functions of different wetland systems over large spatial scales. Seven wetland systems were associated with enhanced transport of either nitrogen or phosphorus in streams, probably because of the export of dissolved organic nitrogen and bank erosion. Six wetland systems were associated with mitigating the delivery of either nitrogen or phosphorus to streams, probably because of sedimentation, phosphate sorption, and ground water infiltration.

Where did all the Nitrogen go? Use of Watershed-Scale Budgets to Quantify Nitrogen Inputs, Storages, and Losses.

NASA Astrophysics Data System (ADS)

Boyer, E. W.; Goodale, C. L.; Howarth, R. W.; VanBreemen, N.

2001-12-01

Inputs of nitrogen (N) to aquatic and terrestrial ecosystems have increased during recent decades, primarily from the production and use of fertilizers, the planting of N-fixing crops, and the combustion of fossil fuels. We present mass-balanced budgets of N for 16 catchments along a latitudinal profile from Maine to Virginia, which encompass a range of climatic variability and are major drainages to the coast of the North Atlantic Ocean. We quantify inputs of N to each catchment from atmospheric deposition, application of nitrogenous fertilizers, biological nitrogen fixation by crops and trees, and import of N in agricultural products (food and feed). We relate these input terms to losses of N (total, organic, and nitrate) in streamflow. The importance of the relative N sources to N exports varies widely by watershed and is related to land use. Atmospheric deposition was the largest source of N to the forested catchments of northern New England (e.g., Penobscot and Kennebec); import of N in food was the largest source of N to the more populated regions of southern New England (e.g., Charles and Blackstone); and agricultural inputs were the dominant N sources in the Mid-Atlantic region (e.g., Schuylkill and Potomac). In all catchments, N inputs greatly exceed outputs, implying additional loss terms (e.g., denitrification or volatilization and transport of animal wastes), or changes in internal N stores (e.g, accumulation of N in vegetation, soil, or groundwater). We use our N budgets and several modeling approaches to constrain estimates about the fate of this excess N, including estimates of N storage in accumulating woody biomass, N losses due to in-stream denitrification, and more. This work is an effort of the SCOPE Nitrogen Project.

What does atmospheric nitrogen contribute to the Gulf of Mexico area of oxygen depletion?

NASA Astrophysics Data System (ADS)

Rabalais, N. N.

2017-12-01

The northern Gulf of Mexico influenced by the freshwater discharge and nutrient loads of the Mississippi River watershed is the location of the world's second largest human-caused area of coastal hypoxia. Over 500 more anthropogenic `dead zones' exist in coastal waters. The point source inputs within the Mississippi River watershed account for about ten per cent of the total nitrogen inputs to the Mississippi River, with the remaining being nonpoint source. Atmospheric nitrogen makes up about sixteen per cent of the nonpoint source input of nitrogen. Most of the NOx is generated within the Ohio River watershed from the burning of fossil fuels. Some remains to be deposited into the same watershed, but the airshed deposits much of the NOx along the U.S. eastern seaboard, including Chesapeake Bay, which also has a hypoxia problem. Most of the volatilized ammonia is produced from fertilizers or manure within the upper Mississippi River watershed, is deposited within a localized airshed, and is not airborne long distances like the NOx. The atmospheric nitrogen input to the coastal waters affected by hypoxia is considered to be minimal. In the last half century, the nitrogen load from the Mississippi River to the Gulf of Mexico has increased 300 percent. During this period, low oxygen bottom-waters have developed in the coastal waters and worsened coincident with the increase in the nitrogen load. The 31-yr average size of the bottom-water hypoxia area in the Gulf of Mexico is 13,800 square kilometers, well over the 5,000 square kilometers goal of the Mississippi River Nutrient/Gulf of Mexico Hypoxia Task Force. Knowing the amounts and sources of excess nutrients to watersheds with adjacent coastal waters experiencing eutrophication and hypoxia is important in the management strategies to reduce those nutrients and improve water quality.

Nitrogen and phosphorus removed from a subsurface flow multi-stage filtration system purifying agricultural runoff.

PubMed

Zhao, Yaqi; Huang, Lei; Chen, Yucheng

2018-07-01

Agricultural nonpoint source pollution has been increasingly serious in China since the 1990s. The main causes were excessive inputs of nitrogen fertilizer and pesticides. A multi-stage filtration system was built to test the purification efficiencies and removal characteristics of nitrogen and phosphorus when treating agricultural runoff. Simulated runoff pollution was prepared by using river water as source water based on the monitoring of local agricultural runoff. Experimental study had been performed from September to November 2013, adopting 12 h for flooding and 12 h for drying. The results showed that the system was made adaptive to variation of inflow quality and quantity, and had good removal for dissolved total nitrogen, total nitrogen, dissolved total phosphorus (DTP), and total phosphorus, and the average removal rate was 27%, 36%, 32%, and 48%, respectively. Except nitrate ([Formula: see text]), other forms of nitrogen and phosphorus all decreased with the increase of stages. Nitrogen was removed mainly in particle form the first stage, and mostly removed in dissolved form the second and third stage. Phosphorus was removed mainly in particulate during the first two stages, but the removal of particulate phosphorus and DTP were almost the same in the last stage. An approximate logarithmic relationship between removal loading and influent loading to nitrogen and phosphorus was noted in the experimental system, and the correlation coefficient was 0.78-0.94. [Formula: see text]: ammonium; [Formula: see text]: nitrite; [Formula: see text]: nitrate; DTN: dissolved total nitrogen; TN: total nitrogen; DTP: dissolved total phosphorus; TP: total phosphorus; PN: particulate nitrogen; PP: particulate phosphorus.

Ecological implications of single and mixed nitrogen nutrition in Arabidopsis thaliana

PubMed Central

2013-01-01

Background Ecologists recognize that plants capture nitrogen in many chemical forms that include amino acids. Access to multiple nitrogen types in plant communities has been argued to enhance plant performance, access to nitrogen and alter ecological interactions in ways that may promote species coexistence. However, data supporting these arguments have been limited. While it is known that plants uptake amino acids from soil, long term studies that link amino acid uptake to measures of plant performance and potential reproductive effort are not typically performed. Here, a series of experiments that link uptake of nitrate, glutamine or asparagine with lifetime reproductive effort in Arabidopsis thaliana are reported. Nitrogen was offered either singly or in mixture and at a variety of combinations. Traits related to reproductive output were measured, as was the preference for each type of nitrogen. Results When plants were supplied with a single nitrogen type at concentrations from 0.1-0.9 mM, the ranking of nitrogen types was nitrate > glutamine > asparagine in terms of the relative performance of plants. When plants were supplied with two types of nitrogen in mixture at ratios between 0.1:0.9-0.9:0.1 mM, again plants performed best when nitrate was present, and poorly when amino acids were mixed. Additionally, stable isotopes revealed that plants preferentially captured nitrogen types matching the hierarchy of nitrate > glutamine > asparagine. Comparing between the two experiments revealed that mixed nitrogen nutrition was a net cost to the plants. Conclusions Plant performance on mixed nitrogen was less than half the performance on equal amounts of any single nitrogen type. We asked: why did A. thaliana capture amino acids when doing so resulted in a net cost? We argue that available data cannot yet answer this question, but hypothesize that access to lower quality forms of nitrogen may become important when plants compete. PMID:23875896

Nitrogen-isotopes and multi-parameter sewage water test for identification of nitrate sources: Groundwater body Marchfeld East of Vienna

NASA Astrophysics Data System (ADS)

Kralik, Martin

2017-04-01

The application of nitrogen and oxygen isotopes in nitrate allows, under favourable circumstances, to identify potential sources such as precipitation, chemical fertilisers and manure or sewage water. Without any additional tracer, the source distinction of nitrate from manure or sewage water is still difficult. Even the application of boron isotopes can in some cases not avoid ambiguous interpretation. Therefore, the Environment Agency Austria developed a new multi parametrical indicator test to allow the identification and quantification of pollution by domestic sewage water. The test analyses 8 substances well known to occur in sewage water: Acesulfame and sucralose (two artificial, calorie-free sweeteners), benzotriazole and tolyltriazole (two industrial chemicals/corrosion inhibitors), metoprolol, sotalol, carbamazepine and the metabolite 10,11-Dihydro-10,11-dihydroxycarbamazepine (pharmaceuticals) [1]. These substances are polar and degradation in the aquatic system by microbiological processes is not documented. These 8 Substances do not occur naturally which make them ideal tracers. The test can detect wastewater in the analysed water sample down to 0.1 %. This ideal coupling of these analytic tests helps to identify the nitrogen sources in the groundwater body Marchfeld East of Vienna to a high confidence level. In addition, the results allow a reasonable quantification of nitrogen sources from different types of fertilizers as well as sewage water contributions close to villages and in wells recharged by bank filtration. Recent investigations of groundwater in selected wells in Marchfeld [2] indicated a clear nitrogen contribution by wastewater leakages (sewers or septic tanks) to the total nitrogen budget. However, this contribution is shrinking and the main source comes still from agricultural activities. [1] Humer, F.; Weiss, S.; Reinnicke, S.; Clara, M.; Grath, J.; Windhofer, G. (2013): Multi parametrical indicator test for urban wastewater influence. EGU General Assembly 2013, held 7-12 April, 2013 in Vienna, Austria, id. EGU2013-5332, EGU2013-5332. [2] Kralik, M.; Humer, F. & Grath, J. (2008): Pilotprojekt Grundwasseralter: Herkunftsanalyse von Nitrat mittels Stickstoff-, Sauerstoff-, Schwefel und Kohlenstoffisotopen. 57 S.2, Environment Agency Austria/Ministry of Agriculture, Forestry, Environment and Water Management, Vienna.

Improved Nitrogen Removal Effect In Continuous Flow A2/O Process Using Typical Extra Carbon Source

NASA Astrophysics Data System (ADS)

Wu, Haiyan; Gao, Junyan; Yang, Dianhai; Zhou, Qi; Cai, Bijing

2010-11-01

In order to provide a basis for optimal selection of carbon source, three typical external carbon sources (i.e. methanol, sodium acetate and leachate) were applied to examine nitrogen removal efficiency of continuous flow A2/O system with the influent from the effluent of grit chamber in the second Kunming wastewater treatment plant. The best dosage was determined, and the specific nitrogen removal rate and carbon consumption rate were calculated with regard to individual external carbon source in A2/O system. Economy and technology analysis was also conducted to select the suitable carbon source with a low operation cost. Experimental results showed that the external typical carbon source caused a remarkable enhancement of system nitrate degradation ability. In comparison with the blank test, the average TN and NH3-N removal efficiency of system with different dosing quantities of external carbon source was improved by 15.2% and 34.2%, respectively. The optimal dosage of methanol, sodium acetate and leachate was respectively up to 30 mg/L, 40 mg/L and 100 mg COD/L in terms of a high nitrogen degradation effect. The highest removal efficiency of COD, TN and NH3-N reached respectively 92.3%, 73.9% and 100% with methanol with a dosage of 30 mg/L. The kinetic analysis and calculation revealed that the greatest denitrification rate was 0.0107 mg TN/mg MLVSSṡd with sodium acetate of 60 mg/L. As to carbon consumption rate, however, the highest value occurred in the blank test with a rate of 0.1955 mg COD/mg MLVSSṡd. Also, further economic analysis proved leachate to be pragmatic external carbon source whose cost was far cheaper than methanol.

Catalytic partial oxidation of hydrocarbons

DOEpatents

Schmidt, Lanny D.; Krummenacher, Jakob J.; West, Kevin N.

2007-08-28

A process for the production of a reaction product including a carbon containing compound. The process includes providing a film of a fuel source including at least one organic compound on a wall of a reactor, contacting the fuel source with a source of oxygen, forming a vaporized mixture of fuel and oxygen, and contacting the vaporized mixture of fuel and oxygen with a catalyst under conditions effective to produce a reaction product including a carbon containing compound. Preferred products include .alpha.-olefins and synthesis gas. A preferred catalyst is a supported metal catalyst, preferably including rhodium, platinum, and mixtures thereof.

Catalytic partial oxidation of hydrocarbons

DOEpatents

Schmidt, Lanny D [Minneapolis, MN; Krummenacher, Jakob J [Minneapolis, MN; West, Kevin N [Minneapolis, MN

2009-05-19

A process for the production of a reaction product including a carbon containing compound. The process includes providing a film of a fuel source including at least one organic compound on a wall of a reactor, contacting the fuel source with a source of oxygen, forming a vaporized mixture of fuel and oxygen, and contacting the vaporized mixture of fuel and oxygen with a catalyst under conditions effective to produce a reaction product including a carbon containing compound. Preferred products include .alpha.-olefins and synthesis gas. A preferred catalyst is a supported metal catalyst, preferably including rhodium, platinum, and mixtures thereof.

Heterotrophic nitrogen removal by Acinetobacter sp. Y1 isolated from coke plant wastewater.

PubMed

Liu, YuXiang; Hu, Tingting; Song, Yujie; Chen, Hongping; Lv, YongKang

2015-11-01

A strain of Acinetobacter sp. Y1, which exhibited an amazing ability to remove ammonium, nitrite and nitrate, was isolated from the activated sludge of a coking wastewater treatment plant. The aim of this work was to study the ability, influence factors and possible pathway of nitrogen removal by Acinetobacter sp. Y1. Results showed that maximum removal rate of NH4(+)-N by the strain was 10.28 mg-N/L/h. Carbon source had significant influence on the growth and ammonium removal efficiencies of strain Y1. Pyruvate, citrate and acetate were favourable carbon sources for the strain. Temperature, pH value and shaking speed could affect the growth and nitrogen removal ability. Nitrate or nitrite could be used as a sole nitrogen source for the growth and removed efficiently by the strain. N2 levels increased to 53.74%, 50.21% and 55.13% within 36 h when 100 mg/L NH4(+)-N, NO2(-)-N or NO3(-) -N was used as sole nitrogen source in the gas detection experiment. The activities of hydroxylamine oxidoreductase (HAO), nitrate reductase (NR) and nitrite reductase (NiR), which are key enzymes in heterotrophic nitrification and aerobic denitrification, were all detectable in the strain. Consequently, a possible pathway for ammonium removal by the strain was also suggested. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Effect of nitrogen sources on some morphological characteristics of in vitro stevia rebaudiana Bertoni.

PubMed

Akbari, F; Arminian, A; Kahrizi, D; Fazeli, A

2017-02-28

Stevia rebaudiana Bertoni belongs to Asteraceae family that leaves 200-300 times sweeter than sugar. Low seed fertility is one of the most important problems in Stevia production. So, Plant tissue culture is an efficient method for mass propagation of Stevia. In this research, we studied the effect of various concentrations of nitrogen on some morphological traits of stevia under in vitro conditions. We used axillary nodes as explants and they were cultured on Murashige and Skoog (MS) medium containing inorganic nitrogen sources i.e. NH4NO3(0, 825 and 1650 mg/l), KNO3(0, 950 and 1900 mg/l) were observed. The cultures were kept for 4 weeks at a temperature of 25±2°C with a photoperiod of 16/8 hour low light/dark each day. Maximum shoot length (89.33 mm), dry weight of plants (0.10 mg) and leaf fresh weight (0.42 mg) was observed on MS medium with 1650 mg/l NH4NO3 and 950 mg/l KNO3. Minimum shoot length (6.13 mm), root length (6.60 mm), leaf number (4.26), leaf dry weight (0.01 mg), leaf fresh weight (0.05 mg), total dry and fresh weight (0.02 and 0.15 mg) and growth rate was observed on a MS medium without nitrogen sources. Moreover, presence of nitrogen sources increases both shooting and rooting in Stevia rebaudiana Bertoni.

Gibbon travel paths are goal oriented.

PubMed

Asensio, Norberto; Brockelman, Warren Y; Malaivijitnond, Suchinda; Reichard, Ulrich H

2011-05-01

Remembering locations of food resources is critical for animal survival. Gibbons are territorial primates which regularly travel through small and stable home ranges in search of preferred, limited and patchily distributed resources (primarily ripe fruit). They are predicted to profit from an ability to memorize the spatial characteristics of their home range and may increase their foraging efficiency by using a 'cognitive map' either with Euclidean or with topological properties. We collected ranging and feeding data from 11 gibbon groups (Hylobates lar) to test their navigation skills and to better understand gibbons' 'spatial intelligence'. We calculated the locations at which significant travel direction changes occurred using the change-point direction test and found that these locations primarily coincided with preferred fruit sources. Within the limits of biologically realistic visibility distances observed, gibbon travel paths were more efficient in detecting known preferred food sources than a heuristic travel model based on straight travel paths in random directions. Because consecutive travel change-points were far from the gibbons' sight, planned movement between preferred food sources was the most parsimonious explanation for the observed travel patterns. Gibbon travel appears to connect preferred food sources as expected under the assumption of a good mental representation of the most relevant sources in a large-scale space.

Analyzing Variability in Landscape Nutrient Loading Using Spatially-Explicit Maps in the Great Lakes Basin

NASA Astrophysics Data System (ADS)

Hamlin, Q. F.; Kendall, A. D.; Martin, S. L.; Whitenack, H. D.; Roush, J. A.; Hannah, B. A.; Hyndman, D. W.

2017-12-01

Excessive loading of nitrogen and phosphorous to the landscape has caused biologically and economically damaging eutrophication and harmful algal blooms in the Great Lakes Basin (GLB) and across the world. We mapped source-specific loads of nitrogen and phosphorous to the landscape using broadly available data across the GLB. SENSMap (Spatially Explicit Nutrient Source Map) is a 30m resolution snapshot of nutrient loads ca. 2010. We use these maps to study variable nutrient loading and provide this information to watershed managers through NOAA's GLB Tipping Points Planner. SENSMap individually maps nutrient point sources and six non-point sources: 1) atmospheric deposition, 2) septic tanks, 3) non-agricultural chemical fertilizer, 4) agricultural chemical fertilizer, 5) manure, and 6) nitrogen fixation from legumes. To model source-specific loads at high resolution, SENSMap synthesizes a wide range of remotely sensed, surveyed, and tabular data. Using these spatially explicit nutrient loading maps, we can better calibrate local land use-based water quality models and provide insight to watershed managers on how to focus nutrient reduction strategies. Here we examine differences in dominant nutrient sources across the GLB, and how those sources vary by land use. SENSMap's high resolution, source-specific approach offers a different lens to understand nutrient loading than traditional semi-distributed or land use based models.

[Nitrogen balance in dairy farm: research progress].

PubMed

Lü, Chao; Qin, Wen-Xiao; Gao, Teng-Yun; Wang, Xiao-Xiao; Han, Zhi-Guo; Li, Jia

2013-01-01

Large dairy farm with intensive management has high stocking density, but generally does not have enough space and normative feces disposal system, resulting in the discharged nitrogen surpassed the environmental carrying capacity of unit area land. Dairy farm is one of the major emission sources of nitrogen discharges in agriculture, where the nitrogen balance has being aroused attention by the experts abroad. The research on the nitrogen flow and nitrogen balance in dairy farm is the basis of the dairy farm nitrogen cycling and management study, as well as the basis for the construction of environmental laws, regulations and policies. The most reliable indicators to evaluate the nitrogen flow and nitrogen balance in dairy farm are nitrogen surplus and nitrogen use efficiency. This paper introduced the concept of nitrogen balance on farm-scale and the nitrogen flow within farm, compared the application scope of nitrogen surplus and nitrogen use efficiency, analyzed the factors affecting the nitrogen balance in dairy farm, and summarized the effective strategies to reduce the nitrogen discharges from dairy farm, aimed to provide references for the nitrogen management of dairy farm in China.

[Harvest of the carbon source in wastewater by the adsorption and desorption of activated sludge].

PubMed

Liu, Hong-Bo; Wen, Xiang-Hua; Zhao, Fang; Mei, Yi-Jun

2011-04-01

The carbon source in municipal wastewater was adsorbed by activated sludge and then harvested through the hydrolysis of activated sludge. Results indicated that activated sludge had high absorbing ability towards organic carbon and phosphorus under continuous operation mode, and the average COD and TP absorption rate reached as high as 63% and 76%, respectively. Moreover, about 50% of the soluble carbon source was outside of the sludge cell and could be released under mild hydrolysis condition. Whereas the absorbed amount of nitrogen was relatively low, and the removal rate of ammonia was only 13% . Furthermore, the releases of organic carbon, nitrogen and phosphorus from the sludge absorbing pollutants in the wastewater were studied. By comparing different hydrolysis conditions of normal (pH 7.5, 20 degrees C), heating (pH 7.5, 60 degrees C) and the alkaline heating (pH 11, 60 degrees C), the last one presented the optimum hydrolysis efficiency. Under which, the release rate of COD could reach 320 mg/g after 24 hours, whereas nitrogen and phosphorus just obtained low release rates of 18 mg/g and 2 mg/g, respectively. Results indicate that the carbon source in wastewater could be harvested by the adsorption and desorption of activated sludge, and the concentrations of nitrogen and phosphorus are low and would not influence the reuse of the harvested carbon source.

Induction of L-phenylalanine ammonia-lyase during utilization of phenylalanine as a carbon or nitrogen source in Rhodotorula glutinis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marusich, W.C.; Jensen, R.A.; Zamir, L.O.

Rhodotorula glutinis is a convenient source of L-phenylalanine ammonia-lyase, an enzyme that is useful as a biochemical reagent in the assay of L-phenylalanine. There have been previous descriptions of induced lyase production in complex medium where induction occurs late in exponential growth, suggesting a role in secondary metabolism such as is the case in higher plants. A higher specific activity of L-phenylalanine ammonia-lyase (sixfold higher than in complex medium) can be obtained during midexponential growth in a defined medium containing L-phenylalanine as the sole source of carbon. L-phenylalanine will also induce lyase synthesis during exponential growth in minimal medium inmore » which L-phenylalanine is the sole source of nitrogen. The appearance of lyase in complex medium supplemented with L-phenylalanine is probably triggered fortuitously by exhaustion late in growth of a prime source of nitrogen. In this study, R. glutinis appeared to express a single lyase enzyme, regardless of whether induction was nitrogen signaled or carbon signaled. Thin-layer chromatographic analysis of ether extracts prepared fom cultures induced with doubly labeled (U-/sup 14/C; ring-4-/sup 3/H) L-phenylalanine provided evidence of a catabolic sequence containing cinnamic acid, benzoic acid, and 4-hydroxybenzoic acid as degradative intermediates. 3,4-Dihydroxybenzoic acid was not identified as a catabolic intermediate.« less

Induction of L-phenylalanine ammonia-lyase during utilization of phenylalanine as a carbon or nitrogen source in Rhodotorula glutinis.

PubMed Central

Marusich, W C; Jensen, R A; Zamir, L O

1981-01-01

Rhodotorula glutinis is a convenient source of L-phenylalanine ammonia-lyase, an enzyme that is useful as a biochemical reagent in the assay of L-phenylalanine. There have been previous descriptions of induced lyase production in complex medium where induction occurs late in exponential growth, suggesting a role in secondary metabolism such as is the case in higher plants. A higher specific activity of L-phenylalanine ammonia-lyase (sixfold higher than a complex medium) can be obtained during midexponential growth in a defined medium containing L-phenylalanine as the sole source of carbon. L-Phenylalanine will also induce lyase synthesis during exponential growth in minimal in which L-phenylalanine is the sole source of nitrogen. The appearance of lyase in complex medium supplemented with L-phenylalanine is probably triggered fortuitously by exhaustion late in growth of a prime source of nitrogen. In this study, R. glutinis appeared to express a single lyase enzyme, regardless of whether induction was nitrogen signaled or carbon signaled. Thin-layer chromatographic analysis of ether extracts prepared from cultures induced with doubly labeled (U-14C; ring-4-3H) L-phenylalanine provided evidence of a catabolic sequence containing cinnamic acid, benzoic acid, and 4-hydroxybenzoic acid as degradative intermediates. 3,4-Dihydroxybenzoic acid was not identified as a catabolic intermediate. PMID:7195398

International Space Station (ISS) Gas Logistics Planning in the Post Shuttle Era

NASA Technical Reports Server (NTRS)

Leonard, Daniel J.; Cook, Anthony J.; Lehman, Daniel A.

2011-01-01

Over its life the International Space Station (ISS) has received gas (nitrogen, oxygen, and air) from various sources. Nitrogen and oxygen are used in the cabin to maintain total pressure and oxygen partial pressures within the cabin. Plumbed nitrogen is also required to support on-board experiments and medical equipment. Additionally, plumbed oxygen is required to support medical equipment as well as emergency masks and most importantly EVA support. Gas are supplied to ISS with various methods and vehicles. Vehicles like the Progress and ATV deliver nitrogen (both as a pure gas and as air) and oxygen via direct releases into the cabin. An additional source of nitrogen and oxygen is via tanks on the ISS Airlock. The Airlock nitrogen and oxygen tanks can deliver to various users via pressurized systems that run throughout the ISS except for the Russian segment. Metabolic oxygen is mainly supplied via cabin release from the Elektron and Oxygen Generator Assembly (OGA), which are water electrolyzers. As a backup system, oxygen candles (Solid Fuel Oxygen Generators-SFOGs) supply oxygen to the cabin as well. In the past, a major source of nitrogen and oxygen has come from the Shuttle via both direct delivery to the cabin as well as to recharge the ISS Airlock tanks. To replace the Shuttle capability to recharge the ISS Airlock tanks, a new system was developed called Nitrogen/Oxygen Recharge System (NORS). NIORS consists of high pressure (7000 psi) tanks which recharge the ISS Airlock tanks via a blowdown fill for both nitrogen and oxygen. NORS tanks can be brought up on most logistics vehicles such as the HTV, COTS, and ATV. A proper balance must be maintained to insure sufficient gas resources are available on-orbit so that all users have the required gases via the proper delivery method (cabin and/or plumbed).

Estimating nitrogen loading and far-field dispersal potential from background sources and coastal finfish aquaculture: A simple framework and case study in Atlantic Canada

NASA Astrophysics Data System (ADS)

McIver, R.; Milewski, I.; Loucks, R.; Smith, R.

2018-05-01

Far-field nutrient impacts associated with finfish aquaculture have been identified as a topic of concern for regulators, managers, scientists, and the public for over two decades but disentangling aquaculture impacts from those caused by other natural and anthropogenic sources has impeded the development of monitoring metrics and management plans. We apply a bulk, steady-state nitrogen loading model (NLM) framework to estimate the annual input of Total Dissolved Nitrogen (TDN) from point and non-point sources to the watershed surrounding Port Mouton Bay, Nova Scotia (Canada). We then use the results of the NLM together with estimates of dissolved inorganic nitrogen (DIN) loading from a sea-cage trout farm in the Bay and progressive vector diagrams to illustrate potential patterns of DIN dispersal from the trout farm. Our estimated anthropogenic nitrogen contribution to Port Mouton Bay from all terrestrial and atmospheric sources is ∼211,703 kg TDN/year with atmospheric deposition accounting for almost all (98.6%). At a stocking level of ∼400,000 rainbow trout, the Port Mouton Bay sea-cage farm increases the annual anthropogenic TDN loading to the bay by 14.4% or 30,400 kg. Depending on current flow rates, nitrogen flux from the trout farm can be more than double the background concentrations of TDN near the farm site. Although it is unlikely that nitrogen loading from this single fish farm is saturating the DIN requirements of the entire bay, progressive vector diagrams suggest that the dispersal potential may be insufficient to mitigate potential symptoms of eutrophication associated with nitrogen fluxes. We present an accessible and user-friendly tool for managers to estimate baseline nutrient loading in relation to aquaculture and our use of progressive vector diagrams illustrate a practical and simple method for characterizing potential nutrient dispersal based on local conditions and spatial scales. Our study joins numerous studies which have highlighted the need for more effective monitoring and assessment methods to improve the detection of aquaculture effects at far-field scales and to assess those effects in relation to other natural and anthropogenic factors impacting coastal habitats.

Genome wide analysis of the complete GlnR nitrogen-response regulon in Mycobacterium smegmatis

PubMed Central

2013-01-01

Background Nitrogen is an essential element for bacterial growth and an important component of biological macromolecules. Consequently, responding to nitrogen limitation is critical for bacterial survival and involves the interplay of signalling pathways and transcriptional regulation of nitrogen assimilation and scavenging genes. In the soil dwelling saprophyte Mycobacterium smegmatis the OmpR-type response regulator GlnR is thought to mediate the transcriptomic response to nitrogen limitation. However, to date only ten genes have been shown to be in the GlnR regulon, a vastly reduced number compared to other organisms. Results We investigated the role of GlnR in the nitrogen limitation response and determined the entire GlnR regulon, by combining expression profiling of M. smegmatis wild type and glnR deletion mutant, with GlnR-specific chromatin immunoprecipitation and high throughput sequencing. We identify 53 GlnR binding sites during nitrogen limitation that control the expression of over 100 genes, demonstrating that GlnR is the regulator controlling the assimilation and utilisation of nitrogen. We also determine a consensus GlnR binding motif and identify key residues within the motif that are required for specific GlnR binding. Conclusions We have demonstrated that GlnR is the global nitrogen response regulator in M. smegmatis, directly regulating the expression of more than 100 genes. GlnR controls key nitrogen stress survival processes including primary nitrogen metabolism pathways, the ability to utilise nitrate and urea as alternative nitrogen sources, and the potential to use cellular components to provide a source of ammonium. These studies further our understanding of how mycobacteria survive nutrient limiting conditions. PMID:23642041

Behavior and Release of Nitrogen at Mines and Quarries in Nordic Conditions

NASA Astrophysics Data System (ADS)

Karlsson, Teemu; Neitola, Raisa; Jermakka, Johannes; Merta, Elina; Mroueh, Ulla-Maija

2015-04-01

The increased extraction of mineral resources and mining activities creates added pressure on the environmental issues and a proper water management in mining areas in Finland. Among others, nitrogen compounds released from explosives or from mining processes can have a detrimental effect on the environment. Thus, this project aimed at comprehensive understanding on the nitrogen issue in the extractive industry. The project collected essential data on nitrogen compounds present in the environments of mines and quarries, and generated better understanding of the discharge and behaviour of nitrogen compounds in mining areas. The sources and balances of explosives-originated nitrogen compounds at mines and quarries of different sizes were investigated and compared. Additionally, the focus was in 'nitrogen smudging' problem of waste rocks and the intensity, as well as evolution and chemical characteristics of their nitrogen contamination. According to the results, the total load of potential nitrogen to the environment depends on the scale and type of the activity as well as the type of explosives used. The main emission sources of nitrogen are process and dewatering waters. A lysimeter study showed that the explosives originated nitrogen content of left over stones from natural stone quarrying is relatively low and ca. half of the nitrogen is leached within the first weeks after detonation. The "nitrogen smudging" of natural stone quarrying left over stones is relatively low to begin with and enhanced by the rapid flushing by rainwater, thus the residues of explosives should not be considered to prevent the utilization of otherwise mineralogically inert waste rocks of good technical quality. The overall nitrogen management should take into account the background concentrations and sensitivity of the local ecosystem. The research project "Solution for Control of Nitrogen Discharges at Mines and Quarries, (MINIMAN)" was realized during years 2012-2014 as a cooperative project with GTK, VTT and TTY together with several industrial and international partners and financed by Tekes Green Mining Programme.

Source Preferences and the Displacement/Supplement Effect between Internet and Traditional Sources of Sexually Transmitted Disease and HIV/AIDS Information

ERIC Educational Resources Information Center

Lu, Hung-Yi

2009-01-01

This investigation examines the source preferences and the displacement/supplement effect of traditional and new channel usage as Taiwanese college students search for information about sexually transmitted diseases and HIV/AIDS from the Internet. The study involved 535 junior and senior college students from four universities. Analytical results…

Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)--discrimination of ammonium nitrate sources.

PubMed

Benson, Sarah J; Lennard, Christopher J; Maynard, Philip; Hill, David M; Andrew, Anita S; Roux, Claude

2009-06-01

An evaluation was undertaken to determine if isotope ratio mass spectrometry (IRMS) could assist in the investigation of complex forensic cases by providing a level of discrimination not achievable utilising traditional forensic techniques. The focus of the research was on ammonium nitrate (AN), a common oxidiser used in improvised explosive mixtures. The potential value of IRMS to attribute Australian AN samples to the manufacturing source was demonstrated through the development of a preliminary AN classification scheme based on nitrogen isotopes. Although the discrimination utilising nitrogen isotopes alone was limited and only relevant to samples from the three Australian manufacturers during the evaluated time period, the classification scheme has potential as an investigative aid. Combining oxygen and hydrogen stable isotope values permitted the differentiation of AN prills from three different Australian manufacturers. Samples from five different overseas sources could be differentiated utilising a combination of the nitrogen, oxygen and hydrogen isotope values. Limited differentiation between Australian and overseas prills was achieved for the samples analysed. The comparison of nitrogen isotope values from intact AN prill samples with those from post-blast AN prill residues highlighted that the nitrogen isotopic composition of the prills was not maintained post-blast; hence, limiting the technique to analysis of un-reacted explosive material.

Facile preparation of N-doped TiO2 at ambient temperature and pressure under UV light with 4-nitrophenol as the nitrogen source and its photocatalytic activities.

PubMed

Horikoshi, Satoshi; Shirasaka, Yutaro; Uchida, Hiroshi; Horikoshi, Natsuko; Serpone, Nick

2016-08-04

To date syntheses of nitrogen-doped TiO2 photocatalysts (TiO2-xNx) have been carried out under high temperatures and high pressures with either NH3 or urea as the nitrogen sources. This article reports for the first time the facile preparation of N-doped TiO2 (P25 titania) in aqueous media at ambient temperature and pressure under inert conditions (Ar- and N2-purged dispersions) with 4-nitrophenol (or 4-nitrobenzaldehyde) as the nitrogen source. The resulting N-doped P25 TiO2 materials were characterized by UV/Vis and X-ray photoelectron spectroscopies (XPS) that confirmed the presence of nitrogen within the photocatalyst; X-ray diffraction (XRD) techniques confirmed the crystalline phases of the doped material. The photocatalytic activity of N-doped TiO2 was assessed through examining the photodegradation of 4-chlorophenol in aqueous media and iso-propanol as a volatile pollutant under UV/Vis and visible-light irradiation. Under visible light irradiation, undoped P25 was inactive contrary to N-doped P25 that successfully degraded 95% of the 4-chlorophenol (after 10 h) and 23% of iso-propanol (after 2.5 h).

A one-pot hydrothermal synthesis of 3D nitrogen-doped graphene aerogels-supported NiS2 nanoparticles as efficient electrocatalysts for the oxygen-reduction reaction

NASA Astrophysics Data System (ADS)

Yuan, Wen-Jing; Li, Ju-Chuan; Chen, Ping; Shen, Yu-Hua; Xie, An-Jian

2014-03-01

Nitrogen-doped graphene aerogels-supported NiS2 nanoparticles (NiS2/NG) were synthesized by a one-pot hydrothermal method. In the process, l-cysteine was used not only as the nitrogen source to form the nitrogen-doped graphene aerogels, but also the sulfur source to form NiS2. The nitrogen-doped graphene (NG) hybrids show an interconnected reticulation of NG sheets with uniform deposition of NiS2 NPs, and the NiS2 NPs are deposited on the NG layers. In studying the effects of the NG and NiS2/NG for the ORR, we found that NiS2/NG shows a more positive onset potential, higher current density, and higher electron transfer number (˜4) for the oxygen-reduction reaction (ORR) in alkaline media than NG. Furthermore, NiS2/NG shows better durability and methanol tolerance than the commercial Pt/C catalyst.

Nitrogen and carbon source-sink relationships in trees at the Himalayan treelines compared with lower elevations.

PubMed

Li, Mai-He; Xiao, Wen-Fa; Shi, Peili; Wang, San-Gen; Zhong, Yong-De; Liu, Xing-Liang; Wang, Xiao-Dan; Cai, Xiao-Hu; Shi, Zuo-Min

2008-10-01

No single hypothesis or theory has been widely accepted for explaining the functional mechanism of global alpine/arctic treeline formation. The present study tested whether the alpine treeline is determined by (1) the needle nitrogen content associated with photosynthesis (carbon gain); (2) a sufficient source-sink ratio of carbon; or (3) a sufficient C-N ratio. Nitrogen does not limit the growth and development of trees studied at the Himalayan treelines. Levels of non-structural carbohydrates (NSC) in trees were species-specific and site-dependent; therefore, the treeline cases studied did not show consistent evidence of source/carbon limitation or sink/growth limitation in treeline trees. However, results of the combined three treelines showed that the treeline trees may suffer from a winter carbon shortage. The source capacity and the sink capacity of a tree influence its tissue NSC concentrations and the carbon balance; therefore, we suggest that the persistence and development of treeline trees in a harsh alpine environment may require a minimum level of the total NSC concentration, a sufficiently high sugar:starch ratio, and a balanced carbon source-sink relationship.

Glucose becomes one of the worst carbon sources for E.coli on poor nitrogen sources due to suboptimal levels of cAMP

PubMed Central

Bren, Anat; Park, Junyoung O.; Towbin, Benjamin D.; Dekel, Erez; Rabinowitz, Joshua D.; Alon, Uri

2016-01-01

In most conditions, glucose is the best carbon source for E. coli: it provides faster growth than other sugars, and is consumed first in sugar mixtures. Here we identify conditions in which E. coli strains grow slower on glucose than on other sugars, namely when a single amino acid (arginine, glutamate, or proline) is the sole nitrogen source. In sugar mixtures with these nitrogen sources, E. coli still consumes glucose first, but grows faster rather than slower after exhausting glucose, generating a reversed diauxic shift. We trace this counterintuitive behavior to a metabolic imbalance: levels of TCA-cycle metabolites including α-ketoglutarate are high, and levels of the key regulatory molecule cAMP are low. Growth rates were increased by experimentally increasing cAMP levels, either by adding external cAMP, by genetically perturbing the cAMP circuit or by inhibition of glucose uptake. Thus, the cAMP control circuitry seems to have a ‘bug’ that leads to slow growth under what may be an environmentally rare condition. PMID:27109914

Global Ozone and Reactive Nitrogen : Composition, Chemistry and Sources

NASA Technical Reports Server (NTRS)

Sing, Hanwant B.; Bradshaw, J.; Davis, D.; Gregory, G.; Talbot, R.

1994-01-01

Ozone plays a central role in the chemistry of the atmosphere both as an ultraviolet shield and as a source of hydroxyl radicals (OH), a potent initiator of atmospheric chemistry. There is evidence to suggest that the ozone abundance in the troposphere (0-10 km) has doubled since the industrial revolution and continues to increase to date. The principle reason for this increase is thought to be the increasing emissions of nitrogen oxides (NO(x)) from anthropogenic activities. Although NO(x) is highly reactive and its products such as HN03 are easily removed by deposition, it now appears that its chemistry is quite complex and it can be transported over long distances via its conversion to a variety of nitrates and penetrates. The sources of atmospheric NO(x) include free tropospheric sources such as lightning and subsonic aircraft, as well as surface emissions which are transported to the free troposphere via convective processes. Recent experimental and theoretical studies have tried to unravel the chemistry of reactive nitrogen species, its sources, and their role in ozone formation. In this presentation we shall describe the results from these studies.

Quantitative proteomics reveals the importance of nitrogen source to control glucosinolate metabolism in Arabidopsis thaliana and Brassica oleracea

PubMed Central

Marino, Daniel; Ariz, Idoia; Lasa, Berta; Santamaría, Enrique; Fernández-Irigoyen, Joaquín; González-Murua, Carmen; Aparicio Tejo, Pedro M.

2016-01-01

Accessing different nitrogen (N) sources involves a profound adaptation of plant metabolism. In this study, a quantitative proteomic approach was used to further understand how the model plant Arabidopsis thaliana adjusts to different N sources when grown exclusively under nitrate or ammonium nutrition. Proteome data evidenced that glucosinolate metabolism was differentially regulated by the N source and that both TGG1 and TGG2 myrosinases were more abundant under ammonium nutrition, which is generally considered to be a stressful situation. Moreover, Arabidopsis plants displayed glucosinolate accumulation and induced myrosinase activity under ammonium nutrition. Interestingly, these results were also confirmed in the economically important crop broccoli (Brassica oleracea var. italica). Moreover, these metabolic changes were correlated in Arabidopsis with the differential expression of genes from the aliphatic glucosinolate metabolic pathway. This study underlines the importance of nitrogen nutrition and the potential of using ammonium as the N source in order to stimulate glucosinolate metabolism, which may have important applications not only in terms of reducing pesticide use, but also for increasing plants’ nutritional value. PMID:27085186