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Sample records for residue-specific 15n csa

  1. Sedentary behavior and residual-specific mortality

    OpenAIRE

    Paul D. Loprinzi; Meghan K. Edwards; Eveleen Sng; Ovuokerie Addoh

    2016-01-01

    Background: The purpose of this study was to examine the association of accelerometer-assessed sedentary behavior and residual-specific mortality. Methods: Data from the 2003-2006 National Health and Nutrition Examination Survey (NHANES) were used (N = 5536), with follow-up through 2011. Sedentary behavior was objectively measured over 7 days via accelerometry. Results: When expressing sedentary behavior as a 60 min/day increase, the hazard ratio across the models ranged from 1.07-1.40 (P < 0...

  2. COMMUNITY SUPPORTED AGRICULTURE (CSA

    Directory of Open Access Journals (Sweden)

    Atănăsoaie George Sebastian

    2013-06-01

    Full Text Available Farms of CSA types are a viable alternative to trade of agricultural products coming from conventional agriculture. These farms are faced with a number of policy issues related to product, price, distribution and promotion. In order to elucidate the issues listed above, we have investigated the literature of specialty. Farmers must make more flexible the content of basket both quantitatively and in terms of the nature of food products offered. Consumers need information on ways of preparation or preservation of products. The growth of the processing degree in farm, and inclusion in the offer of services in ecotourism represent effective options to satisfy consumers. To offset the negative impact of high prices measures should be taken in reducing costs, more flexibility in rescheduling of payments due from customers and compensate for the lack of financial resources with the provision of farm work or subsidize a portion of the basket value from private or government sources. Delivery of baskets should be both at fixed points and at customers domicile. Farmers must provide customers the possibility so that they could harvest themselves the products they will buy. Negative influence of prices will be reduced by establishing an effective communication policy with the market, by organizing events on the farm or nearby towns, through blogs and social networks, and through participation in fairs and exhibitions. A greater customer involvement in farming activities will lead to the implementation of an effective marketing mix.

  3. Influence of the O-phosphorylation of serine, threonine and tyrosine in proteins on the amidic 15N chemical shielding anisotropy tensors

    NARCIS (Netherlands)

    Emmer, J.; Vavrinska, A.; Sychrovský, V.; Benda, L.; Kriz, Z.; Koca, J.; Boelens, R.; Sklenár, V.; Trantirek, L.

    2012-01-01

    Density functional theory was employed to study the influence of O-phosphorylation of serine, threonine, and tyrosine on the amidic 15N chemical shielding anisotropy (CSA) tensor in the context of the complex chemical environments of protein structures. Our results indicate that the amidic 15N CSA

  4. Variability of the 15N chemical shielding tensors in the B3 domain of protein G from 15N relaxation measurements at several fields. Implications for backbone order parameters.

    Science.gov (United States)

    Hall, Jennifer B; Fushman, David

    2006-06-21

    We applied a combination of 15N relaxation and CSA/dipolar cross-correlation measurements at five magnetic fields (9.4, 11.7, 14.1, 16.4, and 18.8 T) to determine the 15N chemical shielding tensors for backbone amides in protein G in solution. The data were analyzed using various model-independent approaches and those based on Lipari-Szabo approximation, all of them yielding similar results. The results indicate a range of site-specific values of the anisotropy (CSA) and orientation of the 15N chemical shielding tensor, similar to those in ubiquitin (Fushman, et al. J. Am. Chem. Soc. 1998, 120, 10947; J. Am. Chem. Soc. 1999, 121, 8577). Assuming a Gaussian distribution of the 15N CSA values, the mean anisotropy is -173.9 to -177.2 ppm (for 1.02 A NH bond length) and the site-to-site CSA variability is +/-17.6 to +/-21.4 ppm, depending on the method used. This CSA variability is significantly larger than derived previously for ribonuclease H (Kroenke, et al. J. Am. Chem. Soc. 1999, 121, 10119) or recently, using "meta-analysis" for ubiquitin (Damberg, et al. J. Am. Chem. Soc. 2005, 127, 1995). Standard interpretation of 15N relaxation studies of backbone dynamics in proteins involves an a priori assumption of a uniform 15N CSA. We show that this assumption leads to a significant discrepancy between the order parameters obtained at different fields. Using the site-specific CSAs obtained from our study removes this discrepancy and allows simultaneous fit of relaxation data at all five fields to Lipari-Szabo spectral densities. These findings emphasize the necessity of taking into account the variability of 15N CSA for accurate analysis of protein dynamics from 15N relaxation measurements.

  5. The measurement of 15N

    International Nuclear Information System (INIS)

    Fiedler, R.

    1984-01-01

    The use of mass spectrometry and emission spectrometry for the determination of 15 N in stable tracer studies is reviewed. Mass spectrometry has the advantage that more accurate results compared to emission spectrometry are possible. Emission spectrometry, however, is less expensive and only requires samples at least 50 times smaller for analysis. The sample preparation method is similar for both techniques. (U.K.)

  6. An optimized method for (15)N R(1) relaxation rate measurements in non-deuterated proteins.

    Science.gov (United States)

    Gairí, Margarida; Dyachenko, Andrey; González, M Teresa; Feliz, Miguel; Pons, Miquel; Giralt, Ernest

    2015-06-01

    (15)N longitudinal relaxation rates are extensively used for the characterization of protein dynamics; however, their accurate measurement is hindered by systematic errors. (15)N CSA/(1)H-(15)N dipolar cross-correlated relaxation (CC) and amide proton exchange saturation transfer from water protons are the two main sources of systematic errors in the determination of (15)N R1 rates through (1)H-(15)N HSQC-based experiments. CC is usually suppressed through a train of 180° proton pulses applied during the variable (15)N relaxation period (T), which can perturb water magnetization. Thus CC cancellation is required in such a way as to minimize water saturation effects. Here we examined the level of water saturation during the T period caused by various types of inversion proton pulses to suppress CC: (I) amide-selective IBURP-2; (II) cosine-modulated IBURP-2; (III) Watergate-like blocks; and (IV) non-selective hard. We additionally demonstrate the effect of uncontrolled saturation of aliphatic protons on (15)N R1 rates. In this paper we present an optimized pulse sequence that takes into account the crucial effect of controlling also the saturation of the aliphatic protons during (15)N R1 measurements in non-deuterated proteins. We show that using cosine-modulated IBURP-2 pulses spaced 40 ms to cancel CC in this optimized pulse program is the method of choice to minimize systematic errors coming from water and aliphatic protons saturation effects.

  7. Synthesis of [2-15N]-perlolyrine from 15N-glycine

    International Nuclear Information System (INIS)

    Tang Ganghua; Wang Shizhen; Wu Shuqin; Jiang Guohui

    1999-01-01

    To study the metabolism of [2- 15 N]-Perlolyrine in animals, [α- 15 N]-dl-tryptophan and [2- 15 N]-perlolyrine are designed and synthesized. [α- 15 N]-dl-Tryptophan is first synthesized from 15 N-glycine via many steps by the use of Al-Ni alloy as a catalytic reduction agent, and then [2- 15 N]-perlolyrine is synthesized from [α- 15 N]-dl-tryptophan. The abundance of 15 N is determined by GC-MS, the chemical purity is determined by TLC and the final product is confirmed by MS, UV and TLC. The overall yield of the final product is 7.3%, the abundance of 15 N is 92% and the chemical purity is 98%. The synthetic [2- 15 N]-perlolyrine is suitable for pharmacological experiments

  8. Resolution of the 15N balance enigma?

    International Nuclear Information System (INIS)

    Clough, T.J.; Sherlock, R.R.; Cameron, K.C.; Stevens, R.J.; Laughlin, R.J.; Mueller, C.

    2001-01-01

    The enigma of soil nitrogen balance sheets has been discussed for over 40 years. Many reasons have been considered for the incomplete recovery of 15 N applied to soils, including sampling uncertainty, gaseous N losses from plants, and entrapment of soil gases. The entrapment of soil gases has been well documented for rice paddy and marshy soils but little or no work appears to have been done to determine entrapment in drained pasture soils. In this study 15 N-labelled nitrate was applied to a soil core in a gas-tight glovebox. Water was applied, inducing drainage, which was immediately collected. Dinitrogen and N -2 were determined in the flux through the soil surface, and in the gases released into the glovebox as a result of irrigation or physical destruction of the core. Other components of the N balance were also measured, including soil inorganic-N and organic-N. Quantitative recovery of the applied 15 N was achieved when the experiment was terminated 484 h after the 15 N-labelled material was applied. Nearly 23% of the 15 N was recovered in the glovebox atmosphere as N 2 and N 2 O due to diffusion from the base of the soil core, convective flow after irrigation, and destructive soil sampling. This 15 N would normally be unaccounted for using the sampling methodology typically employed in 15 N recovery experiments. Copyright (2001) CSIRO Publishing

  9. Effect of dietary 15N-CCC on 15N content of meat and eggs of ...

    African Journals Online (AJOL)

    Udo ter Meulen

    APE in meat differed significantly at P < 0.05 among treatments, whereas those of egg yolk and albumen were similar during the same time period of eleven days. Table 2 Excess δ15N of eggs and meat of laying hens seven days after withdrawal of diets containing varying amounts of 15N-CCC. Excess δ15N. Chicken ...

  10. 15N tracer techniques in pediatric research

    International Nuclear Information System (INIS)

    Heine, W.; Richter, I.; Plath, C.; Wutzke, K.; Stolpe, H.J.; Tiess, M.; Toewe, J.

    1983-01-01

    The main topics of the review comprise mathematical fundamentals of the determination of N metabolism parameters using the 3-pool method, the value of different 15 N tracer substances for the determination of whole-body protein parameters, the utilization of parenterally applied D-amino acids, studies on the influence of different diets on the N metabolism of premature infants with the 15 N tracer technique, the application of the 15 N-glycine-STH-test for the evaluation of the therapeutic effect of STH in children suffering from hypothalamico-hypophyseal dwarfism, in vivo studies on urea utilization by the infant intestinal flora under various dietary regimens as well as in vitro investigations on the utilization of 15 N-labelled urea and NH 4 Cl, resp., by the intestinal flora

  11. Synthesis of hydroxylamine-15 N.HCl

    International Nuclear Information System (INIS)

    Baldea, Aurel

    2001-01-01

    15 N labelled hydroxylamine is one of the starting substance for synthesis of labelled oximes. Industrial procedure was chosen to prepare hydroxylamine- 15 N. Sodium nitrite reduced by sodium bisulfite and sulfur dioxide, at temperature of 0-2 deg. C, produces sodium hydroxylamine disulfonate. The reaction mixture is treated with acetone and the resulting acetoxime is distilled. In order to obtain crystalline hydroxylamine hydrochloride, hydrochloric acid is added to the distillate and the solution is evaporated to dryness. The crude product was purified by recristallization, yielding 62-65% of theoretical amount. Labelled ammonium chloride formed as byproduct can be recovered improving 15 N balance. IR spectra is used for chemical analysis and mass spectrometry for isotopic analysis. For this purpose hydroxylamine- 15 N is converted into molecular nitrogen. (author)

  12. Space astronomy and astrophysics program by CSA

    Science.gov (United States)

    Laurin, Denis; Ouellet, Alain; Dupuis, Jean; Chicoine, Ruth-Ann

    2014-07-01

    Canada became actively engaged in space astronomy in the 1990s by contributing two fine guidance sensors to the FUSE Far-UV mission (NASA 1999-2008). In the same period, Canada contributed to ODIN's infrared instrument (ESA 2001-2006) and correlators for VSOP (JAXA 1997-2005). In early 2000, Canada developed its own space telescope, Micro-variability and Observations of STars (MOST), a 15-cm telescope on a microsatellite, operating since 2003, and more recently contributed to the realization of the BRITE nanosatellites constellation. Canada also provided hardware to the European Space Agency's Herschel HIFI instrument and simulators to the SPIRE instrument and data analysis tools for Planck. More recently the Canadian Space Agency (CSA) delivered detector units for the UVIT instrument on board the Indian Space Research Organisation's (ISRO) ASTROSAT. The CSA's most important contribution to a space astronomy mission to date is the Fine Guidance Senor (FGS) and Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument to NASA's James Webb Space Telescope. The CSA is currently building the laser metrology system for JAXA's ASTRO-H hard X-ray telescope. Canadian astronomers contributed to several high profile stratospheric balloon projects investigating the CMB and the CSA recently established a balloon launch facility. As expressed in Canada's new Space Policy Framework announced in February 2014, Canada remains committed to future space exploration endeavors. The policy aims at ensure that Canada is a sought-after partner in the international space exploration missions that serve Canada's national interests; and continuing to invest in the development of Canadian contributions in the form of advanced systems and optical instruments. In the longer term, through consultations and in keeping the Canadian astronomical community's proposed Long Range Plan, the CSA is exploring possibilities to contributions to important missions such as WFIRST, SPICA and Athena

  13. [Studies with 15N-labeled lysine in colostomized hens. 2. 15N excretion in feces].

    Science.gov (United States)

    Gruhn, K; Wiefel, P

    1983-05-01

    Over a period of four days colostomised hens were given 15N-lysine, and the development of 15N-excretion both in the TCA-soluble and the TCA-precipitable fraction of the faeces was measured over eight days. In both fractions the total, lysine, histidine and arginine N and 15N-excess (15N') was determined. The average apparent digestibility of 14N was 81.2% +/- 1.1% and of 15N' 93.2% +/- 0.7%. Labelled N is already excreted in faeces 3 hours after its application. The TCA-precipitable N is less strongly labelled than the TCA-soluble N. During the application of 15N' the labelling in faecal lysine is nearly one power of ten higher than in total N. The atom-% 15N' of the lysine could also be distinctly detected in arginine and histidine. The quotas of the total 15N' in faeces were 3.5% for arginine-15N' and 0.8% for histidine 15N'; 15N' can mainly be detected in the soluble fraction.

  14. Synthesis of Gemcitabine-13C, 15N2 and Gemcitabine-13C, 15N2 Metabolites

    Directory of Open Access Journals (Sweden)

    ZHU Cheng-gu;YANG Shao-zu;YAN Sheng-wang;FANG Ning-jing;CAI Ding-long;LI Gang

    2014-02-01

    Full Text Available Homemade urea-13C, 15N2 was used to react with 3-methyl acrylonitrile closure to form cytosine-13C, 15N2 (2,which was protected by trimethylsilylation with BSA and condensed with 2-deoxy-2,2-difluoro-D-erythro-pentofuranose-3,5-dibenzoate-1-methanesulfonate at 120 ℃ to afford blocked gemcitabine-13C, 15N2. Hydrolytic removal of the blocking groups of gemcitabine-13C, 15N2 with NaOH gave gemcitabine-13C, 15N2, and its metabolite was obtained by further hydrolytic deamination of gemcitabine-13C, 15N2. The final products were characterized and detected by HPLC, LC-MS and NMR, and confirmed that the chemical purities were higher than 98%, isotopic abundances were 99% 13C, 98% 15N, and they were suitable for drug metabolism studies.

  15. 15N in biological nitrogen fixation studies

    International Nuclear Information System (INIS)

    Faust, H.

    1986-05-01

    A bibliography with 298 references on the use of the stable nitrogen isotope 15 N in the research on the biological fixation of dinitrogen is presented. The literature pertaining to this bibliography covers the period from 1975 to the middle of 1985. (author)

  16. Tracing 15N through landscapes: potential uses and precautions

    NARCIS (Netherlands)

    Bedard-Haughn, A.; Groenigen, van J.W.; Kessel, van C.

    2003-01-01

    Stable N isotopes are used to examine the source, flow and fate of N at scales ranging from greenhouse pots to landscapes. There are two main approaches: the 15N-enriched method applies an artificially enriched source of 15N and the 15N natural abundance (15N) method uses natural 15N differences

  17. Synthesis of organic compounds 15 N enriched

    International Nuclear Information System (INIS)

    Oliveira, Claudineia Raquel de; Bendassolli, Jose Albertino; Prestes, Clelber Vieira; Tavares, Glauco Arnold

    2002-01-01

    The aim of this work was to develop urea- 15 N and glycine- 15 N synthesis for agronomic and biological studies. The production of these compounds was evaluated due to the fact of increasing use of urea, comparing to others solid fertilizers and the importance of glycine in the studies of protein metabolism. A non-conventional method was carried out to synthesize urea. The process involved reaction among Co, NH 3 anidrid and S at low temperature (100 deg C) and of pressure (0,81 mPa) compared to the conventional method. Monolise halets reaction was carried out for glycine synthesis with chloroacetic and ammonia 2 deg C. Both compounds are economic viable, they can be produced at a lower price than the trade market one. (author)

  18. Synthesis of 15N labeled glyphosate

    International Nuclear Information System (INIS)

    Oliveira, Claudineia R. de; Bendassolli, Jose Albertino; Tavares, Glauco Arnold; Rossete, Alexssandra L.R.M.; Tagliassachi, Romulo Barbieri; Prestes, Cleuber Vieira

    2005-01-01

    Amongst the actually commercialized herbicides the Glyphosate is the most used in Brazil. Its efficiency as well as the others herbicides against undesirable weeds is harmed by its final composts left at the environment. Although studies has being carried out to improve the knowledge about the herbicides behavior at the environment its complexity has led them towards innumerous to new significant research work where the use of radiolabeled composts (radiative tracers) are recommended to evaluate their bio-availability in the soil. However is the use, the manipulation and the storage of radiolabeled composts is requires an extra care under chemical safety point of view. The use of non radiolabeled composts is a world tendency especially for field researches. Under this context the presented work describes a method for the synthesis of 15 N labeled glyphosate. The 15 N-herbicide was undertaken by phosphometilation with the phosphit dialquil and 15 N-glycine. The tests where carried out through a micro scale production plant and of equimolars amounts. At these conditions it's was possible to reach approximately a 20% of yield. At the conclusion of a best operational condition its expected to offer another important toll that shall be used in glyphosate behavior at the environment and undesirably weeds. (author)

  19. A novel pig feed formulation containing Aspergillus niger CSA35 ...

    African Journals Online (AJOL)

    This study investigated the effects of Aspergillus niger CSA35 pretreated-cassava (Manihot esculenta Crantz) peel feed (CPFG) on the body weight gain and some selected biochemical parameters of pigs. Cassava peels treated with biomass of A. niger CSA35 for a period of three weeks to initiate enzymatic digestion of ...

  20. Effect of CSA Concentration on the Ammonia Sensing Properties of CSA-Doped PA6/PANI Composite Nanofibers

    Directory of Open Access Journals (Sweden)

    Zengyuan Pang

    2014-11-01

    Full Text Available Camphor sulfonic acid (CSA-doped polyamide 6/polyaniline (PA6/PANI composite nanofibers were fabricated using in situ polymerization of aniline under different CSA concentrations (0.02, 0.04, 0.06, 0.08 and 0.10 M with electrospun PA6 nanofibers as templates. The structural, morphological and ammonia sensing properties of the prepared composite nanofibers were studied using scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FT-IR, four-point probe techniques, X-ray diffraction (XRD and a home-made gas sensing test system. All the results indicated that the CSA concentration had a great influence on the sensing properties of CSA-doped PA6/PANI composite nanofibers. The composite nanofibers doped with 0.02 M CSA showed the best ammonia sensing properties, with a significant sensitivity toward ammonia (NH3 at room temperature, superior to that of the composite nanofibers doped with 0.04–0.10 mol/L CSA. It was found that for high concentrations of CSA, the number of PANI–H+ reacted with NH3 would not make up a high proportion of all PANI–H+ within certain limits. As a result, within a certain range even though higher CSA-doped PA6/PANI nanofibers had better conductivity, their ammonia sensing performance would degrade.

  1. Synthesis of 15N isotope labeled alanine

    International Nuclear Information System (INIS)

    Oliveira, Claudineia R. de; Bendassolli, Jose Albertino; Sant'Ana, Carlos Roberto; Tagliassachi, Romulo Barbieri; Maximo, Everaldo; Prestes, Clelber Vieira

    2005-01-01

    The application of light chemical elements and their stable isotopes in biological studies have been increased over the last years. The use of 15 N labeled amino acids is an important tool for elucidation of peptides structures. This paper describe a method for the synthesis of 15 N isotope labeled alanine at lower costs than international ones, as well as the details of the recovery system of the nitrogen residues. In the present work an amination of α-haloacids, with the bromopropionic carboxylic acid and labeled aqua ammonia ( 15 NH 3 aq) was carried out. In order to avoid eventually losses of 15 NH 3 , special cares were adopted, since the production cost is high. Although the acquisition cost of the 13 N (radioactive) labeled compounds is lower, the obtained stable tracer will allow the accomplishment of important studies of the nitrogen cycling in living things, less occupational and environment hazards, and the time limitation problems in field studies. The tests took place in triplicates with NH 3 (aq) being employed. With the establishment of the system for 15 NH 3 recovery, an average of 94 % of the ammonia employed in the synthesis process was recovered. The purity of the amino acid was state determined by TLC (Thin Layer Chromatography) and HPLC (High-Performance Liquid Chromatography) with a fluorescence detector. The Rf and the retention time of the synthesized sample were similar the sigma standard. Finally, regarding the established conditions, it was possible to obtain the alanine with a production cost about 40 % lower than the international price. (author)

  2. Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly 15N labeled integral membrane proteins in magnetically aligned lipid bilayers

    International Nuclear Information System (INIS)

    Mote, Kaustubh R.; Gopinath, T.; Traaseth, Nathaniel J.; Kitchen, Jason; Gor’kov, Peter L.; Brey, William W.; Veglia, Gianluigi

    2011-01-01

    Oriented solid-state NMR is the most direct methodology to obtain the orientation of membrane proteins with respect to the lipid bilayer. The method consists of measuring 1 H- 15 N dipolar couplings (DC) and 15 N anisotropic chemical shifts (CSA) for membrane proteins that are uniformly aligned with respect to the membrane bilayer. A significant advantage of this approach is that tilt and azimuthal (rotational) angles of the protein domains can be directly derived from analytical expression of DC and CSA values, or, alternatively, obtained by refining protein structures using these values as harmonic restraints in simulated annealing calculations. The Achilles’ heel of this approach is the lack of suitable experiments for sequential assignment of the amide resonances. In this Article, we present a new pulse sequence that integrates proton driven spin diffusion (PDSD) with sensitivity-enhanced PISEMA in a 3D experiment ([ 1 H, 15 N]-SE-PISEMA-PDSD). The incorporation of 2D 15 N/ 15 N spin diffusion experiments into this new 3D experiment leads to the complete and unambiguous assignment of the 15 N resonances. The feasibility of this approach is demonstrated for the membrane protein sarcolipin reconstituted in magnetically aligned lipid bicelles. Taken with low electric field probe technology, this approach will propel the determination of sequential assignment as well as structure and topology of larger integral membrane proteins in aligned lipid bilayers.

  3. Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly {sup 15}N labeled integral membrane proteins in magnetically aligned lipid bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Mote, Kaustubh R. [University of Minnesota, Department of Chemistry (United States); Gopinath, T. [University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics (United States); Traaseth, Nathaniel J. [New York University, Chemistry Department (United States); Kitchen, Jason; Gor' kov, Peter L.; Brey, William W. [National High Magnetic Field Laboratory (United States); Veglia, Gianluigi, E-mail: vegli001@umn.edu [University of Minnesota, Department of Chemistry (United States)

    2011-11-15

    Oriented solid-state NMR is the most direct methodology to obtain the orientation of membrane proteins with respect to the lipid bilayer. The method consists of measuring {sup 1}H-{sup 15}N dipolar couplings (DC) and {sup 15}N anisotropic chemical shifts (CSA) for membrane proteins that are uniformly aligned with respect to the membrane bilayer. A significant advantage of this approach is that tilt and azimuthal (rotational) angles of the protein domains can be directly derived from analytical expression of DC and CSA values, or, alternatively, obtained by refining protein structures using these values as harmonic restraints in simulated annealing calculations. The Achilles' heel of this approach is the lack of suitable experiments for sequential assignment of the amide resonances. In this Article, we present a new pulse sequence that integrates proton driven spin diffusion (PDSD) with sensitivity-enhanced PISEMA in a 3D experiment ([{sup 1}H,{sup 15}N]-SE-PISEMA-PDSD). The incorporation of 2D {sup 15}N/{sup 15}N spin diffusion experiments into this new 3D experiment leads to the complete and unambiguous assignment of the {sup 15}N resonances. The feasibility of this approach is demonstrated for the membrane protein sarcolipin reconstituted in magnetically aligned lipid bicelles. Taken with low electric field probe technology, this approach will propel the determination of sequential assignment as well as structure and topology of larger integral membrane proteins in aligned lipid bilayers.

  4. Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly 15N labeled integral membrane proteins in magnetically aligned lipid bilayers.

    Science.gov (United States)

    Mote, Kaustubh R; Gopinath, T; Traaseth, Nathaniel J; Kitchen, Jason; Gor'kov, Peter L; Brey, William W; Veglia, Gianluigi

    2011-11-01

    Oriented solid-state NMR is the most direct methodology to obtain the orientation of membrane proteins with respect to the lipid bilayer. The method consists of measuring (1)H-(15)N dipolar couplings (DC) and (15)N anisotropic chemical shifts (CSA) for membrane proteins that are uniformly aligned with respect to the membrane bilayer. A significant advantage of this approach is that tilt and azimuthal (rotational) angles of the protein domains can be directly derived from analytical expression of DC and CSA values, or, alternatively, obtained by refining protein structures using these values as harmonic restraints in simulated annealing calculations. The Achilles' heel of this approach is the lack of suitable experiments for sequential assignment of the amide resonances. In this Article, we present a new pulse sequence that integrates proton driven spin diffusion (PDSD) with sensitivity-enhanced PISEMA in a 3D experiment ([(1)H,(15)N]-SE-PISEMA-PDSD). The incorporation of 2D (15)N/(15)N spin diffusion experiments into this new 3D experiment leads to the complete and unambiguous assignment of the (15)N resonances. The feasibility of this approach is demonstrated for the membrane protein sarcolipin reconstituted in magnetically aligned lipid bicelles. Taken with low electric field probe technology, this approach will propel the determination of sequential assignment as well as structure and topology of larger integral membrane proteins in aligned lipid bilayers. © Springer Science+Business Media B.V. 2011

  5. Resonances in the nuclear reactions 15N + 12C and 15N + 16O

    International Nuclear Information System (INIS)

    Monnehan, G.A.

    1987-06-01

    The reaction 12 C + 15 N have been studied at 15 N beam energies between 30 and 70 MeV. For each reaction, about twelve residual nuclei have been identified through the γ-ray detection method. Excitation functions were obtained for the fusion and peripheral channels. Resonances are seen in the channels containing at least one α particle at energies below 50 MeV. At higher energies, strong structures are observed in the direct reaction channels. The evolution of the fusion cross section is well reproduced by a model based on the statistical desexcitation of the compound nucleus if the discrete states of the residual nuclei are taken into account. The favourable observation of resonant phenomena in 15 N induced reactions can be understood in terms of a small number of channels open to the grazing wave. In the range 50 to 60 MeV, there is a strong coupling between the fusion and the direct reaction channels. The occurrence of resonances above E lab = 50 MeV in the peripheral channels is explained with the band crossing and effective barrier models. In the 15 N induced reactions, the absorption of the surface waves is weak [fr

  6. 15N-labelled glycine synthesis

    International Nuclear Information System (INIS)

    Tavares, Claudineia R.O.; Bendassolli, Jose A.; Sant'Ana Filho, Carlos R.; Prestes, Clelber V.; Coelho, Fernando

    2006-01-01

    This work describes a method for 15 N-isotope-labeled glycine synthesis, as well as details about a recovery line for nitrogen residues. To that effect, amination of α-haloacids was performed, using carboxylic chloroacetic acid and labeled aqueous ammonia ( 15 NH 3 ). Special care was taken to avoid possible 15 NH 3 losses, since its production cost is high. In that respect, although the purchase cost of the 13 N-labeled compound (radioactive) is lower, the stable tracer produced constitutes an important tool for N cycling studies in living organisms, also minimizing labor and environmental hazards, as well as time limitation problems in field studies. The tests were carried out with three replications, and variable 15 NH 3(aq) volumes in the reaction were used (50, 100, and 150 mL), in order to calibrate the best operational condition; glycine masses obtained were 1.7, 2, and 3.2 g, respectively. With the development of a system for 15 NH 3 recovery, it was possible to recover 71, 83, and 87% of the ammonia initially used in the synthesis. With the required adaptations, the same system was used to recover methanol, and 75% of the methanol initially used in the amino acid purification process were recovered. (author)

  7. Computer Science and Convergence : CSA 2011 & WCC 2011 Proceedings

    CERN Document Server

    Chao, Han-Chieh; Obaidat, Mohammad; Kim, Jongsung

    2012-01-01

    Computer Science and Convergence is proceedings of the 3rd FTRA International Conference on Computer Science and its Applications (CSA-11) and The 2011 FTRA World Convergence Conference (FTRA WCC 2011). The topics of CSA and WCC cover the current hot topics satisfying the world-wide ever-changing needs. CSA-11 will be the most comprehensive conference focused on the various aspects of advances in computer science and its applications and will provide an opportunity for academic and industry professionals to discuss the latest issues and progress in the area of CSA. In addition, the conference will publish high quality papers which are closely related to the various theories and practical applications in CSA. Furthermore, we expect that the conference and its publications will be a trigger for further related research and technology improvements in this important subject. The main scope of CSA-11 is as follows: -      Mobile and ubiquitous computing -      Dependable, reliable and autonomic computi...

  8. An optimized method for {sup 15}N R{sub 1} relaxation rate measurements in non-deuterated proteins

    Energy Technology Data Exchange (ETDEWEB)

    Gairí, Margarida, E-mail: mgairi@rmn.ub.edu [University of Barcelona (CCiTUB), NMR Facility, Scientific and Technological Centers (Spain); Dyachenko, Andrey [Institute for Research in Biomedicine (IRB) (Spain); González, M. Teresa; Feliz, Miguel [University of Barcelona (CCiTUB), NMR Facility, Scientific and Technological Centers (Spain); Pons, Miquel [University of Barcelona, Biomolecular NMR Laboratory and Organic Chemistry Department (Spain); Giralt, Ernest, E-mail: ernest.giralt@irbbarcelona.org [Institute for Research in Biomedicine (IRB) (Spain)

    2015-06-15

    {sup 15}N longitudinal relaxation rates are extensively used for the characterization of protein dynamics; however, their accurate measurement is hindered by systematic errors. {sup 15}N CSA/{sup 1}H–{sup 15}N dipolar cross-correlated relaxation (CC) and amide proton exchange saturation transfer from water protons are the two main sources of systematic errors in the determination of {sup 15}N R{sub 1} rates through {sup 1}H–{sup 15}N HSQC-based experiments. CC is usually suppressed through a train of 180° proton pulses applied during the variable {sup 15}N relaxation period (T), which can perturb water magnetization. Thus CC cancellation is required in such a way as to minimize water saturation effects. Here we examined the level of water saturation during the T period caused by various types of inversion proton pulses to suppress CC: (I) amide-selective IBURP-2; (II) cosine-modulated IBURP-2; (III) Watergate-like blocks; and (IV) non-selective hard. We additionally demonstrate the effect of uncontrolled saturation of aliphatic protons on {sup 15}N R{sub 1} rates. In this paper we present an optimized pulse sequence that takes into account the crucial effect of controlling also the saturation of the aliphatic protons during {sup 15}N R{sub 1} measurements in non-deuterated proteins. We show that using cosine-modulated IBURP-2 pulses spaced 40 ms to cancel CC in this optimized pulse program is the method of choice to minimize systematic errors coming from water and aliphatic protons saturation effects.

  9. A study of 15N- 15N and 15N- 13C spin couplings in some 15N labeled mesoionic 1-oxa and 1-thia-2,3,4-triazoles

    Science.gov (United States)

    Jaźwiński, J.; Staszewska, O.; Stefaniak, L.; Webb, G. A.

    1996-03-01

    15N- 15N and 15N- 13C spin-spin couplings are reported for seven 15N labeled 1-oxa and 1-thia-2,3,4-triazoles and three sydnonimines. For the former class of compounds the spin-spin coupling data show a close similarity between the N2N3 and N3N4 bonds which had not previously been suspected from chemical shift measurements.

  10. Synthesis of {sup 15}N labeled glyphosate; Sintese do glifosato enriquecido com {sup 15}N

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Claudineia R. de; Bendassolli, Jose Albertino; Tavares, Glauco Arnold; Rossete, Alexssandra L.R.M.; Tagliassachi, Romulo Barbieri; Prestes, Cleuber Vieira [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Dept. de Isotopos Estaveis]. E-mail: crolivei@cena.usp.br

    2005-07-01

    Amongst the actually commercialized herbicides the Glyphosate is the most used in Brazil. Its efficiency as well as the others herbicides against undesirable weeds is harmed by its final composts left at the environment. Although studies has being carried out to improve the knowledge about the herbicides behavior at the environment its complexity has led them towards innumerous to new significant research work where the use of radiolabeled composts (radiative tracers) are recommended to evaluate their bio-availability in the soil. However is the use, the manipulation and the storage of radiolabeled composts is requires an extra care under chemical safety point of view. The use of non radiolabeled composts is a world tendency especially for field researches. Under this context the presented work describes a method for the synthesis of {sup 15}N labeled glyphosate. The {sup 15}N-herbicide was undertaken by phosphometilation with the phosphit dialquil and {sup 15}N-glycine. The tests where carried out through a micro scale production plant and of equimolars amounts. At these conditions it's was possible to reach approximately a 20% of yield. At the conclusion of a best operational condition its expected to offer another important toll that shall be used in glyphosate behavior at the environment and undesirably weeds. (author)

  11. Synthesis of [2-15N]-perlolyrine

    International Nuclear Information System (INIS)

    Tang Ganghua; Wang Shizhen; Wu Shuqin; Jiang Guohui

    1998-01-01

    The synthesis of [2- 15 N]-perlolyrine is described. Furfuryl alcohol was first acetylated and formacylated, and then reacted with [α- 15 N]-dl-tryptophan to form the ring-closed product, which was oxidated and hydrolyzed to give the final product. The product was confirmed by MS, UV and TLC. Its yield from [α- 15 N]-dl-tryptophan was 15.5%, and the abundance of 15 N was 92%. The synthetic [2- 15 N]-perlolyrine is therefore suitable for pharmacologic experiments

  12. DNA binding properties of the small cascade subunit Csa5.

    Directory of Open Access Journals (Sweden)

    Michael Daume

    Full Text Available CRISPR-Cas systems provide immunity against viral attacks in archaeal and bacterial cells. Type I systems employ a Cas protein complex termed Cascade, which utilizes small CRISPR RNAs to detect and degrade the exogenic DNA. A small sequence motif, the PAM, marks the foreign substrates. Previously, a recombinant type I-A Cascade complex from the archaeon Thermoproteus tenax was shown to target and degrade DNA in vitro, dependent on a native PAM sequence. Here, we present the biochemical analysis of the small subunit, Csa5, of this Cascade complex. T. tenax Csa5 preferentially bound ssDNA and mutants that showed decreased ssDNA-binding and reduced Cascade-mediated DNA cleavage were identified. Csa5 oligomerization prevented DNA binding. Specific recognition of the PAM sequence was not observed. Phylogenetic analyses identified Csa5 as a universal member of type I-A systems and revealed three distinct groups. A potential role of Csa5 in R-loop stabilization is discussed.

  13. High level of var2csa transcription by Plasmodium falciparum isolated from the placenta

    DEFF Research Database (Denmark)

    Tuikue Ndam, Nicaise G; Salanti, Ali; Bertin, Gwladys

    2005-01-01

    Plasmodium falciparum parasites that bind to chondroitin sulphate A (CSA) express unique variant surface antigens that are involved in the placental sequestration that precipitates pregnancy-associated malaria (PAM). Two var gene subfamilies, var1csa and var2csa, have been associated with CSA bin...

  14. Application of 15N labeling to topics in molecular hematology

    International Nuclear Information System (INIS)

    Lapidot, A.; Irving, C.S.

    1975-01-01

    The amount of information which can be obtained from many types of spectrometric analysis of compounds of hematological interest can be greatly enhanced when measurements are made on a series of isotopically labeled compounds. A murine Friend virus-induced erythroleukemic cell (FLC) culture was found to be a superior biosynthetic system for the preparation of highly and selectively 15 N and 13 C enriched hemoglobins. A mutant of Rhodopseudomonas spheroides was found suitable for the preparation of larger quantities of >90 percent enriched protoporphyrin-IX- 15 N and coproporphyrin-III-- 15 N. A comparison of the 15 N and 13 C NMR spectra of FLC carbomonoxy-[Gly- 15 N]-hemoglobin, carbomonoxy-[Gly- 13 C/sub alpha/]-hemoglobin, α and β globin-[Gly- 15 N] and globin-[Gly- 13 C/sub alpha/] demonstrated 1) 15 N peptide chemical shifts are sensitive to polypeptide sequence, whereas 13 C α-carbon chemical shifts are not, (2) variations in the solvation of the peptide N-H group can be detected in the 15 N spectra but not the 13 C spectra, (3) 15 N heme resonances could not be detected, whereas 13 C resonances could. These studies indicated that in hemoglobin the glycyl N-H resonances are either solvated by H 2 O or hydrogen bonded to peptide C=0 groups. In denatured globin, the majority of the glycyl residues are rapidly exchanging between these two states

  15. Methods of 15N tracer research in biological systems

    International Nuclear Information System (INIS)

    Hirschberg, K.; Faust, H.

    1985-01-01

    The application of the stable isotope 15 N is of increasing importance in different scientific disciplines, especially in medicine, agriculture, and the biosciences. The close correlation between the growing interest and improvements of analytical procedures resulted in remarkable advances in the 15 N tracer technique. On the basis of the latest results of 15 N tracer research in life sciences and agriculture methods of 15 N tracer research in biological systems are compiled. The 15 N methodology is considered under three headings: Chemical analysis with a description of methods of sample preparation (including different separation and isolation methods for N-containing substances of biological and agricultural origin) and special procedures converting ammonia to molecular nitrogen. Isotopic analysis with a review on the most important methods of isotopic analysis of nitrogen: mass spectrometry (including the GC-MS technique), emission spectrometry, NMR spectroscopy, and other analytical procedures. 15 N-tracer techniques with a consideration of the role of the isotope dilution analysis as well as different labelling techniques and the mathematical interpretation of tracer data (modelling, N turnover experiments). In these chapters also sources of errors in chemical and isotopic analysis, the accuracy of the different methods and its importance on tracer experiments are discussed. Procedures for micro scale 15 N analysis and aspects of 15 N analysis on the level of natural abundance are considered. Furthermore some remarks on isotope effects in 15 N tracer experiments are made. (author)

  16. Synthesis of {sup 15}N isotope labeled alanine; Sintese da alanina enriquecida com {sup 15}N

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Claudineia R. de; Bendassolli, Jose Albertino; Sant' Ana, Carlos Roberto; Tagliassachi, Romulo Barbieri; Maximo, Everaldo; Prestes, Clelber Vieira [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Dept. de Isotopos Estaveis]. E-mail: crolivei@cena.usp.br

    2005-07-01

    The application of light chemical elements and their stable isotopes in biological studies have been increased over the last years. The use of {sup 15}N labeled amino acids is an important tool for elucidation of peptides structures. This paper describe a method for the synthesis of {sup 15}N isotope labeled alanine at lower costs than international ones, as well as the details of the recovery system of the nitrogen residues. In the present work an amination of {alpha}-haloacids, with the bromopropionic carboxylic acid and labeled aqua ammonia ({sup 15}NH{sub 3} aq) was carried out. In order to avoid eventually losses of {sup 15}NH{sub 3}, special cares were adopted, since the production cost is high. Although the acquisition cost of the {sup 13}N (radioactive) labeled compounds is lower, the obtained stable tracer will allow the accomplishment of important studies of the nitrogen cycling in living things, less occupational and environment hazards, and the time limitation problems in field studies. The tests took place in triplicates with NH{sub 3} (aq) being employed. With the establishment of the system for {sup 15}NH{sub 3} recovery, an average of 94 % of the ammonia employed in the synthesis process was recovered. The purity of the amino acid was state determined by TLC (Thin Layer Chromatography) and HPLC (High-Performance Liquid Chromatography) with a fluorescence detector. The Rf and the retention time of the synthesized sample were similar the sigma standard. Finally, regarding the established conditions, it was possible to obtain the alanine with a production cost about 40 % lower than the international price. (author)

  17. Synthesis of 15 N, 13 C labelled purines

    International Nuclear Information System (INIS)

    Chiriac, Maria; Axente, D.; Palibroda, N.

    1999-01-01

    The heteronuclear NMR spectroscopy in the structural analysis of proteins and nucleic acids requires labelling with 15 N and 13 C. These NMR studies using oligonucleotides, specifically labelled with 15 N and 13 C, may provide valuable information regarding nucleic acid structure, drug binding and nucleic acid-protein interaction. For this purpose, in the last years we prepared some purines labelled with 15 N and 13 C in different positions, which were requested by Institute Pasteur from Paris, where the labelled purines will be use in enzymatic syntheses of nucleotides - 15 N, 13 C. This paper presents 15 N and 13 C labelling of the following purines: [6 - 15 N] adenine; [1,3,7 - 15 N, 8 - 13 C] xanthine; [1,3,6,7 - 15 N, 8 - 13 C] adenine. The first one was obtained by amination of 6-chloropurine with 15 NH 3 at high pressure and temperature. For the second one the experimental procedure is an adaptation of the synthesis method for the corresponding unlabelled compounds (the Traube method, modified by Bobransky and Synowiedsky). As starting isotopically labelled material we used CO( 15 NH 2 ) 2 , Na 15 NO 2 and H 13 COOH. In the last case because of the possibility to transform purines one into another, we prepared labelled adenine in the mentioned positions, using [1,3,7 - 15 N, 8 - 13 C] xanthine as starting material. The 15 N - labelled compounds, CO( 15 NH 2 ) 2 , Na 15 NO 2 and 15 NH 3 , used as starting material for labelling of these purines, were obtained from H 15 NO 3 99 at. % 15 N, produced at the National Institute for Research and Development for Isotopic and Molecular Technologies, Cluj-Napoca, Romania. The labelled purines structure was confirmed using mass spectrometry, IR spectroscopy, NMR spectroscopy and the isotopic label was determined by mass spectrometry on the molecular compounds. (authors)

  18. Synthesis of fertilizers nitrogen and 15N-enriched. Pt. I. Production of enriched 15N-anhydrous ammonia

    International Nuclear Information System (INIS)

    Bendassolli, J.A.; Mortatti, J.; Trivelin, P.C.O.; Victoria, R.L.

    1988-01-01

    The results of 15 N-anhydrous ammonia production through reaction between 15 N-enriched ammonium sulphate and sodium hidroxide are reported. Influence of the reaction temperature, carrier gas flow, reaction time and mass of ammonium sulphate on the production of anhydrous ammonia were studied. Analyses for the cost of production of 5% atoms in 15 N-enriched anhydrous ammonia were made. (M.A.C.) [pt

  19. 15N sample preparation for mass spectroscopy analysis

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.; Salati, E.; Matsui, E.

    1973-01-01

    Technics for preparing 15 N samples to be analised is presented. Dumas method and oxidation by sodium hypobromite method are described in order to get the appropriate sample. Method to calculate 15 N ratio from mass spectrometry dates is also discussed [pt

  20. Biosynthesis of stable isotope 15N labeled spirulina

    International Nuclear Information System (INIS)

    Ren Zheng; Du Xiaoning; Hou Jinghua; Zhang Jingmei

    2010-01-01

    The spirulina is a phototrophic organism. It was considered as the best of nutritional health product. The nitrogen atoms of spirulina was replaced with 15 N stable isotope by the method of biosynthesis. So 15 N labeled spirulina is a nutritional health product and stable isotope tracer product. As a tracer, 15 N labeled spirulina plays an irreplaceable part in bioscience, medicine metabolism and pathology metabolism and so on. 15 N label spirulina is cultivated only in a small scale because of expensive 15 N material. The culture temperature, shine intensity, pH for spirulina were studied. Some feasible conditions were obtained such as 25℃, 3000-4000 lux, initial pH9.0 in the room. 15 N label spirulin prescription was obtained via orthogonal experiment. The optimize prescription of spirulina was that sodium bicarbonate was 13 g · L-1, 15 N-urea was 0.2 g · L -1 , potassium phosphate dibasic was 0.6 g · L -1 , and glucose was 2 g · L -1 . The cost of 15 N material has a significant reduction. The abundance was more than 98%. (authors)

  1. 1H-15N correlation spectroscopy of nanocrystalline proteins

    International Nuclear Information System (INIS)

    Morcombe, Corey R.; Paulson, Eric K.; Gaponenko, Vadim; Byrd, R. Andrew; Zilm, Kurt W.

    2005-01-01

    The limits of resolution that can be obtained in 1 H- 15 N 2D NMR spectroscopy of isotopically enriched nanocrystalline proteins are explored. Combinations of frequency switched Lee-Goldburg (FSLG) decoupling, fast magic angle sample spinning (MAS), and isotopic dilution via deuteration are investigated as methods for narrowing the amide 1 H resonances. Heteronuclear decoupling of 15 N from the 1 H resonances is also studied. Using human ubiquitin as a model system, the best resolution is most easily obtained with uniformly 2 H and 15 N enriched protein where the amides have been exchanged in normal water, MAS at ∼20 kHz, and WALTZ-16 decoupling of the 15 N nuclei. The combination of these techniques results in average 1 H lines of only ∼0.26 ppm full width at half maximum. Techniques for optimizing instrument stability and 15 N decoupling are described for achieving the best possible performance in these experiments

  2. A selective 15N-to- 1H polarization transfer sequence for more sensitive detection of 15N-choline

    Science.gov (United States)

    Pfeilsticker, Jessica A.; Ollerenshaw, Jason E.; Norton, Valerie A.; Weitekamp, Daniel P.

    2010-07-01

    The sensitivity and information content of heteronuclear nuclear magnetic resonance is frequently optimized by transferring spin order of spectroscopic interest to the isotope of highest detection sensitivity prior to observation. This strategy is extended to 15N-choline using the scalar couplings to transfer polarization from 15N to choline's nine methyl 1H spins in high field. A theoretical analysis of a sequence using nonselective pulses shows that the optimal efficiency of this transfer is decreased by 62% as the result of competing 15N- 1H couplings involving choline's four methylene protons. We have therefore incorporated a frequency-selective pulse to support evolution of only the 15N-methyl 1H coupling during the transfer period. This sequence provides a 52% sensitivity enhancement over the nonselective version in in vitro experiments on a sample of thermally polarized 15N-choline in D 2O. Further, the 15N T1 of choline in D 2O was measured to be 217 ± 38 s, the 15N-methyl 1H coupling constant was found to be 0.817 ± 0.001 Hz, and the larger of choline's two 15N-methylene 1H coupling constants was found to be 3.64 ± 0.01 Hz. Possible improvements and applications to in vivo experiments using long-lived hyperpolarized heteronuclear spin order are discussed.

  3. Determination of 13C CSA Tensors: Extension of the Model-independent Approach to an RNA Kissing Complex Undergoing Anisotropic Rotational Diffusion in Solution

    International Nuclear Information System (INIS)

    Ravindranathan, Sapna; Kim, Chul-Hyun; Bodenhausen, Geoffrey

    2005-01-01

    Chemical shift anisotropy (CSA) tensor parameters have been determined for the protonated carbons of the purine bases in an RNA kissing complex in solution by extending the model-independent approach [Fushman, D., Cowburn, D. (1998) J. Am. Chem. Soc. 120, 7109-7110]. A strategy for determining CSA tensor parameters of heteronuclei in isolated X-H two-spin systems (X = 13 C or 15 N) in molecules undergoing anisotropic rotational diffusion is presented. The original method relies on the fact that the ratio κ 2 =R 2 auto /R 2 cross of the transverse auto- and cross-correlated relaxation rates involving the X CSA and the X-H dipolar interaction is independent of parameters related to molecular motion, provided rotational diffusion is isotropic. However, if the overall motion is anisotropic κ 2 depends on the anisotropy D parallel /D -perpendicular of rotational diffusion. In this paper, the field dependence of both κ 2 and its longitudinal counterpart κ 1 =R 1 auto /R 1 cross are determined. For anisotropic rotational diffusion, our calculations show that the average κ av = 1/2 (κ 1 +κ 2 ), of the ratios is largely independent of the anisotropy parameter D parallel /D -perpendicular . The field dependence of the average ratio κ av may thus be utilized to determine CSA tensor parameters by a generalized model-independent approach in the case of molecules with an overall motion described by an axially symmetric rotational diffusion tensor

  4. Competition for tracer 15N in tussock tundra ecosystems

    International Nuclear Information System (INIS)

    Marion, G.M.; Miller, P.C.; Black, C.H.

    1987-01-01

    The objectives of this study were to assess the roles of plant species, time, and site on competition for tracer 15 N (without carrier) in tussock tundra ecosystems. Six experimental sites were located in northern Alaska. After one year across the experimental sites, the recovery of 15 N by litter (11.3-16.3%) and mosses (5.4-16.4%) was significantly greater than for aboveground vascular plants (2.6-5.0%). 15 N recoveries by tundra vascular plants (2.6-5.0%) were low when compared to forest trees (9-25%) which suggst that competition for nitrogen is particularly severe in these colddominated tundra ecosystems. There were no significant differences among sites in 15 N recoveries by vascular plants, by mosses, or by litter. There was a statistically significant decline in 15 N recovery with time for Vaccinium vitis-idaea and Eriophoum vaginatum between the second and third year. The shallow rooted Vaccinium vitis-ideae was more highly labeled than the deep rooted Eriophorum vaginatum. Nearness to the source of the applied 15 N played a critical role in competition for surface applied nitrogen. (author)

  5. Novel adenovirus encoded virus-like particles displaying the placental malaria associated VAR2CSA antigen

    DEFF Research Database (Denmark)

    Andersson, Anne-Marie C; dos Santos Marques Resende, Mafalda; Salanti, Ali

    2017-01-01

    and the CSA binding region of VAR2CSA has been identified as a promising vaccine target against placental malaria. Here we designed adenovirus encoded virus-like particles (VLP) by co-encoding Simian Immunodeficiency Virus (SIV) gag and VAR2CSA. The VAR2CSA antigen was fused to the transmembrane (TM...... revealed a unique targeting of several epitopes in mice that had been primed with VAR2CSA HA TM-CT. Consequently, modification of VLP anchors is an important point of optimization in virus-encoded retroviral VLP-based vaccines, and adenovirus VLPs boosted by recombinant proteins offer hope of increasing...

  6. 15 N separation in the Nitrox system under pressure

    International Nuclear Information System (INIS)

    Axente, D.; Baldea, A.; Teaca, C.; Horga, R.; Abrudean, M.

    1999-01-01

    The basic isotope exchange reaction responsible for the separation of 15 N in Nitrox system is that between gaseous nitrogen oxides and aqueous nitric acid with single stage separation factor α = 1.055 for M.l -1 nitric acid, at 25 deg. C and atmospheric pressure. The rate of nitrogen isotope exchange between NO and HNO 3 has been measured as a function of nitric oxide pressure 0.1 - 0.4 MPa for 1 and 2 M.l -1 . It is concluded that 15 N/ 14 N exchange rate in NO-HNO 3 system has a linear dependence on NO pressure as indicated by rate measurements at different NO partial pressure and constant overall pressure, by adding helium in reactor. Using the rate law: R = [HNO 3 ] 2 [N 2 O 3 ] the 15 N/ 14 N exchange rates for nitric acid concentrations 1.5 - 10 M.l -1 were calculated. In order to know what happens in 15 N separation at higher pressure, when the isotopic transport between two phases is improved, a stainless steel laboratory experimental setup with 1000 mm long x 18 mm i,d. column, packed with triangular wire springs 1.8 x 1.8 x 0.2 mm was utilised. At 0.15 MPA and 2.36 ml.cm -2 . min -1 flow rate HETP was 7% smaller than at atmospheric pressure and 1.5 times smaller flow rate. HETP at 3.14 ml . cm -2 . min -1 flow rate and 0.18 MPa is practically equal with that obtained at atmospheric pressure and 2 times smaller flow rate. The operation of the 15 N separation setup at 0.18 MPa, instead of atmospheric pressure, will permit to double the 10 M.l -1 nitric acid flow rate and of 15 N production of the given column. (authors)

  7. Isotopic enrichment of 15N by ionic exchange chromatography

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.

    1979-01-01

    The present paper presents some studies on production of 15 N-enriched ammonium sulphate with 5% atoms by ionic exchange chromatography method. Two systems are described of columns of resin, where experiments were conducted by eluition of NH 4 + bands with sodium hydroxide solution. Analyses were made of the cost of production of 15 N-enriched ammonium sulphate 5% atoms and, based on the experiments developed, a cost was obtained which was compatible with the international price of the product. The isotopic analyses of nitrogen were made by mass spectrometry. (Author) [pt

  8. CSA guide to Canadian wind turbine codes and standards

    International Nuclear Information System (INIS)

    2008-01-01

    The Canadian wind energy sector has become one of the fastest-growing wind energy markets in the world. Growth of the industry has been supported by various government agencies. However, many projects have experienced cost over-runs or cancellations as a result of unclear regulatory requirements, and wind energy developers are currently subject to a variety of approval processes involving several different authorities. This Canadian Standards Association (CSA) guide provided general information on codes and standards related to the design, approval, installation, operation, and maintenance of wind turbines in Canada. CSA codes and standards were developed by considering 5 new standards adopted by the International Electrotechnical Commission (IEC) Technical Committee on Wind Turbines. The standards described in this document related to acoustic noise measurement techniques; power performance measurements of electricity-producing wind turbines; lightning protection for wind turbine generator systems; design requirements for turbines; and design requirements for small wind turbines. The guide addressed specific subject areas related to the development of wind energy projects that involve formal or regulatory approval processes. Subject areas included issues related to safety, environmental design considerations, site selection, and mechanical systems. Information on associated standards and codes was also included

  9. PANI-CSA films: ageing and kinetics of conductivity degradation

    Science.gov (United States)

    Rannou, P.; Nechtschein, M.

    1998-06-01

    Ageing of PANI-CSA films has been studied through conductivity decay kinetics obtained within 358 and 446 K. For short ageing time, the conductivity loss is partly reversible. For longer one, first order kinetics is observed. This process is arrhenian-like, with an activation energy linked to the PANI quality. Extrapolation at RT predicts stability over centuries. Studies conducted on different atmospheres and FTIR characterization correlate the conductivity decay with various chemical degradations (oxydation, chemical crosslinking, dedoping and ring sulfonation mechanisms). On a étudié les cinétiques de dégradation de la conductivité de films de PANI-CSA entre 358 et 446 K. Aux temps courts de vieillissement, la perte de conductivité est partiellement réversible. Aux temps longs, elle décroît comme une cinétique du 1er ordre. Le processus est de type arréhnien, avec une énergie d'activation liée à la qualité de la PANI. L'extrapolation à température ambiante prévoit une stabilité sur plusieurs siècles. Les cinétiques sous différentes atmosphères et les études par spectroscopie IRTF corrèlent la perte de conduvtivité à divers types de modifications chimiques (oxydation, réticulation, dédopage et sulfonation des cycles).

  10. Designing a VAR2CSA-based vaccine to prevent placental malaria.

    Science.gov (United States)

    Fried, Michal; Duffy, Patrick E

    2015-12-22

    Placental malaria (PM) due to Plasmodium falciparum is a major cause of maternal, fetal and infant mortality, but the mechanisms of pathogenesis and protective immunity are relatively well-understood for this condition, providing a path for vaccine development. P. falciparum parasites bind to chondroitin sulfate A (CSA) to sequester in the placenta, and women become resistant over 1-2 pregnancies as they acquire antibodies that block adhesion to CSA. The protein VAR2CSA, a member of the PfEMP1 variant surface antigen family, mediates parasite adhesion to CSA, and is the leading target for a vaccine to prevent PM. Obstacles to PM vaccine development include the large size (∼ 350 kD), high cysteine content, and sequence variation of VAR2CSA. A number of approaches have been taken to identify the combination of VAR2CSA domains and alleles that can induce broadly active antibodies that block adhesion of heterologous parasite isolates to CSA. This review summarizes these approaches, which have examined VAR2CSA fragments for binding activity, antigenicity with naturally acquired antibodies, and immunogenicity in animals for inducing anti-adhesion or surface-reactive antibodies. Two products are expected to enter human clinical studies in the near future based on N-terminal VAR2CSA fragments that have high binding affinity for CSA, and additional proteins preferentially expressed by placental parasites are also being examined for their potential contribution to a PM vaccine. Copyright © 2015. Published by Elsevier Ltd.

  11. Kinetic 15N-isotope effects on algal growth

    Science.gov (United States)

    Andriukonis, Eivydas; Gorokhova, Elena

    2017-03-01

    Stable isotope labeling is a standard technique for tracing material transfer in molecular, ecological and biogeochemical studies. The main assumption in this approach is that the enrichment with a heavy isotope has no effect on the organism metabolism and growth, which is not consistent with current theoretical and empirical knowledge on kinetic isotope effects. Here, we demonstrate profound changes in growth dynamics of the green alga Raphidocelis subcapitata grown in 15N-enriched media. With increasing 15N concentration (0.37 to 50 at%), the lag phase increased, whereas maximal growth rate and total yield decreased; moreover, there was a negative relationship between the growth and the lag phase across the treatments. The latter suggests that a trade-off between growth rate and the ability to adapt to the high 15N environment may exist. Remarkably, the lag-phase response at 3.5 at% 15N was the shortest and deviated from the overall trend, thus providing partial support to the recently proposed Isotopic Resonance hypothesis, which predicts that certain isotopic composition is particularly favorable for living organisms. These findings confirm the occurrence of KIE in isotopically enriched algae and underline the importance of considering these effects when using stable isotope labeling in field and experimental studies.

  12. Nitrogen and 15N in the Mer Bleue peatland

    Science.gov (United States)

    Moore, Tim

    2017-04-01

    Although much of our attention in peatlands has focussed on carbon, as CO2, CH4 and DOC processing and fluxes, N plays an important role in the functioning of these ecosystems. Here, I present information on the distribution of N and 15N in plant and peat tissues and relate them to the cycling of N. N concentration in foliar tissues, ranged from 0.67 to 1.3% in evergreen shrubs and trees and mosses with little seasonal variation, and with a strong seasonal variation from 0.5 to 3.5% in the deciduous forbs, shrubs and trees, with a strong overall relationship to [chlorophyll]. Although the proportion of shrubs and mosses varied with microtopography the spatial foliar mass of N varied little with water table position, resulting in minor spatial variations in photosynthetic potential. Decomposition of plant tissues through litter to peat resulted in a decrease in the C:N ratio from about 50:1 to about 30:1 at the base of the profile, representing peat about 8000 yr old. This marginally larger loss of N through decomposition (mainly as TDN, 0.4 g N m-2 yr-1) compared to C produced a long-term N accumulation rate of 0.9 g N m-2 yr-1, being smaller in the bog phase, 0.6 N m-2 yr-1, and over past 150 yr, 0.8 g N m-2 yr-1. Although N is 'hard won' through N2 fixation, northern peatlands are significant global sinks of N and have limited N availability. del15N in foliar tissues ranged from -4 to -9 ‰ in evergreen and deciduous shrubs and trees, from -4 to -5 ‰ in mosses and from -1 to +1 ‰ in sedges and forbs. This appears to be a function of the mycorhizzal infection of the shrubs and trees, compared to sedges and forbs and the values for mosses may partially reflect the signature of atmospheric N deposition. There was no strong correlation between foliar [N] and del15N. In peat profiles from bog and fen sections of Mer Bleue, del15N values in peat fell from -5 to -2 ‰ in the top 10 cm to values of -1 to +1 ‰ at a depth of 40 cm and remained close to 0 ‰ below

  13. Isotopic enrichment of 15N by ionic exchange cromatography

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.; Matsui, E.; Salati, E.

    1979-01-01

    The ionic exchange chromatographic method in columns of resin which is employed in the study of isotopic enrichment of 15 N is presented. Determinations are made of the isotopic separation constant for the exchange of isotopes 15 N and 14 N in the equilibrium involving ammonium hidroxide in the solution phase and ions NH 4 + adsorbed in cationic resins: Dowex 50W-X8 and X12, 100-200 mesh. Experiments are also conducted for determination of height of theoretical plates for situations of equilibrium of the NH 4 + band in two systems of resin's columns aimed at estimating the experimental conditions used. The isotopic analyses of nitrogen are carried out by mass spectrometry [pt

  14. True cooking aroma or artefact. 15N gives the answer

    International Nuclear Information System (INIS)

    Metro, F.; Boudaud, N.; Dumont, J.P.

    1994-01-01

    In order to determine the respective contributions of the various nitrous precursor families in aroma preparations, the usually added amino acids were substituted with 15 N isotope labelled homologous components. Results concerning isotope ratios for the volatile fraction nitrous components collected from poultry meat aromatic preparations, are presented. Terminal product labelling appears to allow for a better determination of the substrate and functional additive contributions. 4 figs., 6 refs

  15. Geomorphic control on the δ15N of mountain forests

    Directory of Open Access Journals (Sweden)

    R. G. Hilton

    2013-03-01

    Full Text Available Mountain forests are subject to high rates of physical erosion which can export particulate nitrogen from ecosystems. However, the impact of geomorphic processes on nitrogen budgets remains poorly constrained. We have used the elemental and isotopic composition of soil and plant organic matter to investigate nitrogen cycling in the mountain forest of Taiwan, from 24 sites with distinct geomorphic (topographic slope and climatic (precipitation, temperature characteristics. The organic carbon to nitrogen ratio of soil organic matter decreased with soil 14C age, providing constraint on average rates of nitrogen loss using a mass balance model. Model predictions suggest that present day estimates of nitrogen deposition exceed contemporary and historic nitrogen losses. We found ∼6‰ variability in the stable isotopic composition (δ15N of soil and plants which was not related to soil 14C age or climatic conditions. Instead, δ15N was significantly, negatively correlated with topographic slope. Using the mass balance model, we demonstrate that the correlation can be explained by an increase in nitrogen loss by non-fractioning pathways on steeper slopes, where physical erosion most effectively removes particulate nitrogen. Published data from forests on steep slopes are consistent with the correlation. Based on our dataset and these observations, we hypothesise that variable physical erosion rates can significantly influence soil δ15N, and suggest particulate nitrogen export is a major, yet underappreciated, loss term in the nitrogen budget of mountain forests.

  16. Absorption of ammonium sulphate 15N by coffee plants

    International Nuclear Information System (INIS)

    Fenilli, Tatiele Anete Bergamo; Reichardt, Klaus; Bacchi, Osny Oliveira Santos; Trivelin, Paulo Cesar Ocheuze; Dourado Neto, Durval

    2005-01-01

    The objective of this study was to quantify the absorption of ammonium sulphate 15 N by coffee plants. Treatments consisted of five sub-plots of 9 plants, of which the three central ones received 280 kg ha -1 of 15 N, applied at four times: 1/4 on 01 Set 03; 1/4 on 03 Nov 03; 1/4 on 15 Dec 03 and 1/4 on 30 Jan 04. The isotopic enrichment was 2,072 ± 0,001 atom % 15 N. The dry matter of the shoot was evaluated every 60 days, using one plant per replicate, collected outside the sub-plot. They were as similar as possible to the labeled plants, which were used only for isotopic and Total N analysis, after being dried at 65 deg C until constant weight. At harvest, plants had absorbed 42,88% of the fertilizer N. Leaves accumulated the largest amount of fertilizer N, and were also the compartments that received most N from other parts of the plant. The following partition of the fertilizer N was found at harvest: 23.01% in young leaves, 6.23% in old leaves, 4,46% in stem, 3.46% in fruits, 3.10% in young branches and 2.63% in old branches. (author)

  17. 18O isotope shift in 15N NMR spectroscopy. 2. Synthesis of 15N, 18O-labeled hydroxylamine hydrochloride

    International Nuclear Information System (INIS)

    Rajendran, G.; Van Etten, R.L.

    1986-01-01

    Since hydroxylamine can serve as a key intermediate in the synthesis of a variety of compounds, the synthesis of [ 15 N, 18 O]-labelled hydroxylamine hydrochloride was undertaken. Published procedures for the synthesis of hydroxylamine resulted in poor yields in some cases and in lower percentage of 18 O in the product than expected in other cases. The compound was synthesized in dry tetrahydrofuran (THF) by treating NaNO 2 with borane-methyl sulfide. The course of the reaction was examined using 11 B NMR spectroscopy, and the product yield was 74%. The 18 O enrichment was demonstrated by both mass spectrometry and 15 N NMR of the isolated acetoxime. 23 references, 1 figure

  18. COVALENT BINDING OF REDUCED METABOLITES OF [15N3] TNT TO SOIL ORGANIC MATTER DURING A BIOREMEDIATION PROCESS ANALYZED BY 15N NMR SPECTROSCOPY. (R826646)

    Science.gov (United States)

    Evidence is presented for the covalent binding ofbiologically reduced metabolites of 2,4,6-15N3-trinitrotoluene(TNT) to different soil fractions (humic acids, fulvicacids, and humin) using liquid 15N NMR spectroscopy. Asilylation p...

  19. Clinical development of a VAR2CSA-based placental malaria vaccine PAMVAC

    DEFF Research Database (Denmark)

    Gbédandé, Komi; Fievet, Nadine; Viwami, Firmine

    2017-01-01

    Background  The antigen VAR2CSA plays a pivotal role in the pathophysiology of pregnancy-associated malaria (PAM) caused by Plasmodium falciparum. A VAR2CSA-based vaccine candidate, PAMVAC, is under development by an EU-funded multi-country consortium (PlacMalVac project). As part of PAMVAC...

  20. Effect of estrogens on urinary 15N balance in girls

    International Nuclear Information System (INIS)

    Zachmann, M.; Kempken, B.; Prader, A.

    1984-01-01

    While the anabolic and growth-promoting effects of testosterone are known to be important for pubertal growth in boys, the role of estrogens (E) in the female spurt is less certain. Adrenal androgens have been considered to be more important than ovarian E. To study the anabolic effects of E, there has been carried out a pilot study in 9 girls aged 11 to 15 years. Before and 6 days after the start of E treatment, urinary 15 N balance studies were performed, using 15 NH 4 Cl. (author)

  1. Optimizing expression of the pregnancy malaria vaccine candidate, VAR2CSA in Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Narum David L

    2009-06-01

    Full Text Available Abstract Background VAR2CSA is the main candidate for a vaccine against pregnancy-associated malaria, but vaccine development is complicated by the large size and complex disulfide bonding pattern of the protein. Recent X-ray crystallographic information suggests that domain boundaries of VAR2CSA Duffy binding-like (DBL domains may be larger than previously predicted and include two additional cysteine residues. This study investigated whether longer constructs would improve VAR2CSA recombinant protein secretion from Pichia pastoris and if domain boundaries were applicable across different VAR2CSA alleles. Methods VAR2CSA sequences were bioinformatically analysed to identify the predicted C11 and C12 cysteine residues at the C-termini of DBL domains and revised N- and C-termimal domain boundaries were predicted in VAR2CSA. Multiple construct boundaries were systematically evaluated for protein secretion in P. pastoris and secreted proteins were tested as immunogens. Results From a total of 42 different VAR2CSA constructs, 15 proteins (36% were secreted. Longer construct boundaries, including the predicted C11 and C12 cysteine residues, generally improved expression of poorly or non-secreted domains and permitted expression of all six VAR2CSA DBL domains. However, protein secretion was still highly empiric and affected by subtle differences in domain boundaries and allelic variation between VAR2CSA sequences. Eleven of the secreted proteins were used to immunize rabbits. Antibodies reacted with CSA-binding infected erythrocytes, indicating that P. pastoris recombinant proteins possessed native protein epitopes. Conclusion These findings strengthen emerging data for a revision of DBL domain boundaries in var-encoded proteins and may facilitate pregnancy malaria vaccine development.

  2. Comparison of the specificity of antibodies to VAR2CSA in Cameroonian multigravidae with and without placental malaria

    DEFF Research Database (Denmark)

    Babakhanyan, Anna; Fang, Rui; Wey, Andrew

    2015-01-01

    BACKGROUND: Antibodies (Ab) to VAR2CSA prevent Plasmodium falciparum-infected erythrocytes from sequestrating in the placenta, i.e., prevent placental malaria (PM). The specificity of Ab to VAR2CSA associated with absence of PM is unknown. Accordingly, differences in the specificity of Ab to VAR2......CSA were compared between multigravidae with and without PM who had Ab to VAR2CSA. METHODS: In a retrospective case-control study, plasma collected from Cameroonian multigravidae with (n = 96) and without (n = 324) PM were screened in 21 assays that measured antibody levels to full length VAR2CSA (FV2......), individual VAR2CSA DBL domains, VAR2CSA domains from different genetic backgrounds (variants), as well as proportion of high avidity Ab to FV2. RESULTS: Multigravidae with and without PM had similar levels of Ab to FV2, the six VAR2CSA DBL domains and different variants, while the proportion of high avidity...

  3. The chondroitin sulfate A-binding site of the VAR2CSA protein involves multiple N-terminal domains

    DEFF Research Database (Denmark)

    Dahlbäck, Madeleine; Jørgensen, Lars M; Nielsen, Morten A

    2011-01-01

    by a parasite expressed protein named VAR2CSA. A vaccine protecting pregnant women against placental malaria should induce antibodies inhibiting the interaction between VAR2CSA and CSA. Much effort has been put into defining the part of the 350 kDa VAR2CSA protein that is responsible for binding. It has been...... of truncated VAR2CSA proteins. The experiments indicate that the core of the CSA-binding site is situated in three domains, DBL2X-CIDR(PAM) and a flanking domain, located in the N-terminal part of VAR2CSA. Furthermore, recombinant VAR2CSA subfragments containing this region elicit antibodies with high parasite...

  4. Visualizing the principal component of 1H,15N-HSQC NMR spectral changes that reflect protein structural or functional properties: application to troponin C

    International Nuclear Information System (INIS)

    Robertson, Ian M.; Boyko, Robert F.; Sykes, Brian D.

    2011-01-01

    Laboratories often repeatedly determine the structure of a given protein under a variety of conditions, mutations, modifications, or in a number of states. This approach can be cumbersome and tedious. Given then a database of structures, identifiers, and corresponding 1 H, 15 N-HSQC NMR spectra for homologous proteins, we investigated whether structural information could be ascertained for a new homolog solely from its 1 H, 15 N-HSQC NMR spectrum. We addressed this question with two different approaches. First, we used a semi-automated approach with the program, ORBplus. ORBplus looks for patterns in the chemical shifts and correlates these commonalities to the explicit property of interest. ORBplus ranks resonances based on consistency of the magnitude and direction of the chemical shifts within the database, and the chemical shift correlation of the unknown protein with the database. ORBplus visualizes the results by a histogram and a vector diagram, and provides residue specific predictions on structural similarities with the database. The second method we used was partial least squares (PLS), which is a multivariate statistical technique used to correlate response and predictor variables. We investigated the ability of these methods to predict the tertiary structure of the contractile regulatory protein troponin C. Troponin C undergoes a closed-to-open conformational change, which is coupled to its function in muscle. We found that both ORBplus and PLS were able to identify patterns in the 1 H, 15 N-HSQC NMR data from different states of troponin C that correlated to its conformation.

  5. VAR2CSA expression on the surface of placenta-derived Plasmodium falciparum-infected erythrocytes

    DEFF Research Database (Denmark)

    Magistrado, Pamela; Salanti, Ali; Tuikue Ndam, Nicaise G

    2008-01-01

    intervillous space and parasite antigens. Both placental and chondroitin sulphate A-selected parasites have high-level transcripts of a unique var gene named var2csa. However, VAR2CSA has not been consistently found by proteomic analysis of placental parasites. Contrary to this, we found VAR2CSA expressed...... on the surface of infected erythrocytes from placenta. Importantly, this was achieved with cross-reactive antibodies against VAR2CSA.......Malaria remains a major threat, in sub-Saharan Africa primarily, and the most deadly infections are those with Plasmodium falciparum. Pregnancy-associated malaria is a clinically important complication of infection; it results from a unique interaction between proteoglycans in the placental...

  6. Interresidue carbonyl-carbonyl polarization transfer experiments in uniformly 13C, 15N-labeled peptides and proteins

    Science.gov (United States)

    Janik, Rafal; Ritz, Emily; Gravelle, Andrew; Shi, Lichi; Peng, Xiaohu; Ladizhansky, Vladimir

    2010-03-01

    In this work, we demonstrate that Homonuclear Rotary Resonance Recoupling (HORROR) can be used to reintroduce carbonyl-carbonyl interresidue dipolar interactions and to achieve efficient polarization transfer between carbonyl atoms in uniformly 13C, 15N-labeled peptides and proteins. We show that the HORROR condition is anisotropically broadened and overall shifted to higher radio frequency intensities because of the CSA effects. These effects are analyzed theoretically using Average Hamiltonian Theory. At spinning frequencies used in this study, 22 kHz, this broadening is experimentally found to be on the order of a kilohertz at a proton field of 600 MHz. To match HORROR condition over all powder orientations, variable amplitude radio frequency (RF) fields are required, and efficient direct transfers on the order of 20-30% can be straightforwardly established. Two- and three-dimensional chemical shift correlation experiments establishing long-range interresidue connectivities (e.g., (N[i]-CO[i - 2])) are demonstrated on the model peptide N-acetyl-valine-leucine, and on the third immunoglobulin binding domain of protein G. Possible future developments are discussed.

  7. Initial Assessment of CSA Group Niobium Boron Based Coatings on 4340 Steel

    Science.gov (United States)

    2017-07-01

    for protection of high-strength steel . 15. SUBJECT TERMS Niobium-Boron Based Coatings; 4340 Steel ; CSA Group 16. SECURITY CLASSIFICATION OF: 17...Technical Report ARWSB-TR-17026 Initial Assessment of CSA Group Niobium-Boron Based Coatings on 4340 Steel C.P. Mulligan... Steel 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) C.P. Mulligan 5d. PROJECT NUMBER

  8. Dynamics of anti-VAR2CSA immunoglobulin G response in a cohort of senegalese pregnant women

    DEFF Research Database (Denmark)

    Tuikue Ndam, N G; Salanti, A; Le-Hesran, J-Y

    2006-01-01

    (VSAPAM). Several studies have shown that 1 var gene, var2csa, is transcribed at high levels and expressed in CSA-binding Plasmodium falciparum parasites. METHODS: Plasma levels of anti-VAR2CSA immunoglobulin G (IgG) in Senegalese women were measured during pregnancy by enzyme-linked immunosorbent assay...... demonstrated that a single P. falciparum infection was able to trigger a VAR2CSA-specific antibody response. Among women with infected placentas, women with high anti-VAR2CSA IgG levels at enrollment were more likely to present with a past infection than with an acute/chronic infection. CONCLUSIONS: Anti-VAR2...

  9. Dynamic CO₂ inhalation: a novel treatment for CSR-CSA associated with CHF.

    Science.gov (United States)

    Wan, Zhi Hui; Wen, Fang Jing; Hu, Ke

    2013-05-01

    Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) is very common in patients with chronic congestive heart failure (CHF). A current concept of the key pathophysiological mechanism leading to CSR-CSA is a fluctuation of PaCO2 below and above the apneic threshold. A number of therapeutic approaches for CSR-CSA have been proposed-all with varying success, some of which include various modes of positive airway pressure among other strategies. However, CO2 oscillations seen in CSR-CSA have yet to be looked at as a specific therapeutic target by current treatments. Previous studies have shown that delivery of constant CO2 is efficacious in eliminating CSR-CSA by raising PaCO2, but there are serious concerns about the potential side effects, such as unwanted elevations in ventilation, work of breathing, and sympathetic nerve activity (SNA), and consequently CO2 inhalation therapy has not been recommended as a routine option for therapy. However, recent new studies into CO2 inhalation therapy have been made that may reshape its role as therapeutic. In this review, we will focus on the recent developments of administration of dynamic CO2 in the management of CSR-CSA in CHF patients.

  10. Investigation of the metabolism of colostomized laying hens with 15N-labelled wheat. 6

    International Nuclear Information System (INIS)

    Gruhn, K.; Hennig, A.

    1980-01-01

    Three colostomized laving hens received 40 g 15 N-labelled wheat with 20.13 atom-% 15 N excess ( 15 N'), 19.18 atom-% 15 N'-lysine, 18.17 atom-% 15 N'-histidine and 20.43 atom-% 15 N'-arginine per day over a period of four days. After having received the same non-labelled feed ration on the following four days, the hens were slaughtered. The incorporation and distribution of 15 N' in the total nitrogen and the nitrogen of the basic amino acids was determined in liver, kidneys, muscles, bones and the remaining carcass (excluding blood, digestive tract and genital organs). The quota of nitrogen of natural isotope frequency ( 14 N) of the total 14 N of the hens' carcasses was 47% in the muscles, 14% in the bones and 20% in the feathers; the relative 15 N' values were 37%, 8% and 1%, resp. The atom-% 15 N' in the kidneys was twice as much as in the liver four days after the last 15 N' application. The average percentage of the nitrogen in the three basic amino acids of the total nitrogen in the tissues and organs (excluding feathers) is 25% concerning both 14 N and 15 N'. The 15N' balance revealed that in hen 1 100%, in hen 2 102% and in hen 3 101% of the consumed wheat 15 N' were found. (author)

  11. Fate of orally administered {sup 15}N-labeled polyamines in rats bearing solid tumors

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Masaki; Samejima, Keijiro; Goda, Hitomi; Niitsu, Masaru [Josai Univ., Sakado, Saitama (Japan). Faculty of Pharmaceutical Sciences; Xu Yongji [Qingdao Univ. of Science and Technology (China). Inst. of Chemical and Molecular Technology; Takahashi, Masakazu [Sasaki Inst., Tokyo (Japan); Hashimoto, Yoshiyuki [Kyoritsu Coll. of Pharmacy, Tokyo (Japan)

    2003-03-01

    We studied absorption, distribution, metabolism, and excretion of polyamines (putrescine, spermidine, and spermine) in the gastrointestinal tract using {sup 15}N-labeled polyamines as tracers and ionspray ionization mass spectrometry (IS-MS). The relatively simple protocol using rats bearing solid tumors provided useful information. Three {sup 15}N-labeled polyamines that were simultaneously administered were absorbed equally from gastrointestinal tract, and distributed within tissues at various concentrations. The uptake of {sup 15}N-spermidine seemed preferential to that of {sup 15}N-spermine since the concentrations of {sup 15}N-spermidine in the liver and tumors were higher, whereas those of {sup 15}N-spermine were higher in the kidney, probably due to the excretion of excess extracellular spermine. Most of the absorbed {sup 15}N-putrescine seemed to be lost, suggesting blood and tissue diamine oxidase degradation. Concentrations of {sup 15}N-spermidine and {sup 15}N-spermine in the tumor were low. We also describe the findings from two rats that were administered with {sup 15}N-spermine. The tissue concentrations of {sup 15}N-spermine were unusually high, and significant levels of {sup 15}N-spermidine were derived from {sup 15}N-spermine in these animals. (author)

  12. High efficacy of anti DBL4e-VAR2CSA antibodies in inhibition of CSA-binding Plasmodium falciparum-infected erythrocytes from pregnant women

    DEFF Research Database (Denmark)

    Magistrado, Pamela A; Minja, Daniel; Doritchamou, Justin

    2011-01-01

    Malaria during pregnancy is a major cause of intra-uterine growth-retardation and infant death in sub-Saharan Africa. Ideally, this could be prevented by a vaccine delivered before the first pregnancy. Antibodies against domain DBL4¿ from VAR2CSA has been shown to inhibit adhesion of laboratory...

  13. Evidence for globally shared, cross-reacting polymorphic epitopes in the pregnancy-associated malaria vaccine candidate VAR2CSA

    DEFF Research Database (Denmark)

    Avril, Marion; Kulasekara, Bridget R; Gose, Severin O

    2008-01-01

    Pregnancy-associated malaria (PAM) is characterized by the placental sequestration of Plasmodium falciparum-infected erythrocytes (IEs) with the ability to bind to chondroitin sulfate A (CSA). VAR2CSA is a leading candidate for a pregnancy malaria vaccine, but its large size ( approximately 350 k......Da) and extensive polymorphism may pose a challenge to vaccine development. In this study, rabbits were immunized with individual VAR2CSA Duffy binding-like (DBL) domains expressed in Pichia pastoris or var2csa plasmid DNA and sera were screened on different CSA-binding parasite lines. Rabbit antibodies to three...... recombinant proteins (DBL1, DBL3, and DBL6) and four plasmid DNAs (DBL1, DBL3, DBL5, and DBL6) reacted with homologous FCR3-CSA IEs. By comparison, antibodies to the DBL4 domain were unable to react with native VAR2CSA protein unless it was first partially proteolyzed with trypsin or chymotrypsin...

  14. Incorporation of 15N-labelled nitrate state nitrogen into free amino acids in germinated corn

    International Nuclear Information System (INIS)

    Samukawa, Kisaburo; Yamaguchi, Masuro

    1979-01-01

    15 N-labelling of free amino acids in the blastodisks and albumen parts of corn seeds germinated in 15 N-labelled compound solution was studied to obtain knowledge about the producing ability of amino acids there. From 4th to 12th day after germination, 15 N-incorporation into free amino acids was low both in the blastodisks and albumen parts, and the ratio of 15 N-amino acids was 1 - 2%. Among free amino acids, only aspartic acid and asparagine incorporated comparatively much 15 N. Free lysine and free serine scarcely incorporated 15 N (both in the blastodisks and albumen parts), and internal amino acids seemed to be utilized for germination. Since highly 15 N-labelled free amino acids originated from external nitrogen were not produced, it was clarified that the nitrogen in cultivating ground (added with K 15 NO 3 , 99 atm % excess 15 N) was scarcely utilized. (Kobatake, H.)

  15. Fate of 15N-urea and 15N-ammonium sulphate applied in different periods to cica-8 rice culture in greenhouse conditions

    International Nuclear Information System (INIS)

    Bastidas, O.G.; Alvarez, A.; Victoria, R.L.; Urquiaga C, S.; Muraoka, T.

    1984-01-01

    The fate of nitrogen fertilizers in rice cultivars (Cica-8) is studied. Urea (1.973% at of 15 N) and ammonium sulfate (1.826% at of 15 N) are used. The fertilizers are applied in four levels (0,100,200 and 300 Kg N/ha) in shadow coditions and after 30 days of germination. (M.A.C.) [pt

  16. Metabolic studies in colostomized laying hens using 15N-labelled wheat. 4

    International Nuclear Information System (INIS)

    Gruhn, K.; Glotz, D.

    1979-01-01

    3 colostomized laying hybrids received over 4 days a dosage of 672 mg 15 N excess ( 15 N'), 20.3 mg lysine 15 N', 23.0 mg histidine 15 N' and 66.7 mg arginine 15 N' with a ration customary in production. After feeding the same unlabelled ration for another 4 days the hens were killed and the N content of the blood as well as of its fractions (cells, plasma, free amino acids of the plasma) was determined. The 15 N' was determined in the total blood, the corpuscles, the plasma, the nonprotein-N (NPN) fraction as well as in the amino acids lysine, histidine and arginine. The average amount of the blood cell N in the total blood N was 58.5% and that of the plasma 40.3%; the corresponding 15 N' values amounted to 66.1% and 33.9%, respectively. The sum of the 15 N' of the basic amino acids of the blood cells, on an average, amounted to 39.7% of the total cell 15 N'; the corresponding average value for the total 15 N' in lysine, histidine and arginine of the blood plasma 15 N' was 23.6.% and the quota of the three free amino acids of the total NP 15 N' of the plasma was 6.2%. (author)

  17. Regional patterns in foliar 15N across a gradient of nitrogen deposition in the northeastern US

    Science.gov (United States)

    Linda H. Pardo; Steven G. McNulty; Johnny L. Boggs; Sara Duke

    2007-01-01

    Recent studies have demonstrated that natural abundance 15N can be a useful tool for assessing nitrogen saturation, because as nitrification and nitrate loss increase, d15N of foliage and soil also increases. We measured foliar d15N at 11 high-elevation spruce-fir stands along an N deposition gradient...

  18. In vitro investigations on microbial incorporation of nitrogen from [15N2]urea and [15N2]ammonium chloride by the human intestinal flora

    International Nuclear Information System (INIS)

    Stolpe, H.J.; Heine, W.; Bohnenstengel, C.M.; Gruette, F.K.; Wutzke, K.

    1987-01-01

    6 typical bacteria species of the human intestinal flora (E. coli, Klebsiella pneumoniae, Proteus vulgaris, Streptococcus faecalis, Bacteroides fragilis, Bifidobacterium sp.) were incubated in a liquid medium for 48 h with [ 15 N 2 ]urea and [ 15 N]ammonium chloride. The rates of 15 N incorporation were calculated. They depend reproducibly on the species examined, on the kind of the offered NPN substance and on the amount of NPN substance in the medium. With [ 15 N 2 ]urea the minimal rate of incorporation was 3.8% (E. coli) and the maximal one 95.6% (Bifidobacterium sp.). With [ 15 N]ammonium chloride the corresponding figures were 31.0 (Proteus vulg.) and 98.0% (Bifidobacterium sp.). The findings are discussed with regard to a possible enteral detoxification in uremic patients by bacterial utilization and elimination of urea and ammonia. (author)

  19. The effect of organic matter and nitrification inhibitor on 15 N H4 and 15 N O3 absorption by the maize

    International Nuclear Information System (INIS)

    Saito, S.M.T.

    1974-01-01

    The effect of the forms 15 N H 4 and 15 N O 3 in presence or absence of organic matter and of the nitrification inhibitor AM (2-amino-4-chloro-6-methyl-pyrimidine) in dry matter weight and nitrogen content of the plant derived from soil and form fertilizer is studied. The experiment was carried out in greenhouse and the test plant was the hybrid Maize Centralmex . The fertilizers ( 15 N H 4 ) 2 S O 4 and Na 15 N O 3 , were added in two levels: 40 and 120 Kg N/ha, with 1,02% of N and 1,4% of 15 N in excess, respectively. Three soils of different physical and chemical characteristics were used; Regosol intergrade, Latosol Roxo and Podzolized de Lins e Marilia var. Marilia. (M.A.C.)

  20. Utilizing nanobody technology to target non-immunodominant domains of VAR2CSA.

    Directory of Open Access Journals (Sweden)

    Sisse B Ditlev

    Full Text Available Placental malaria is a major health problem for both pregnant women and their fetuses in malaria endemic regions. It is triggered by the accumulation of Plasmodium falciparum-infected erythrocytes (IE in the intervillous spaces of the placenta and is associated with foetal growth restriction and maternal anemia. IE accumulation is supported by the binding of the parasite-expressed protein VAR2CSA to placental chondroitin sulfate A (CSA. Defining specific CSA-binding epitopes of VAR2CSA, against which to target the immune response, is essential for the development of a vaccine aimed at blocking IE adhesion. However, the development of a VAR2CSA adhesion-blocking vaccine remains challenging due to (i the large size of VAR2CSA and (ii the extensive immune selection for polymorphisms and thereby non-neutralizing B-cell epitopes. Camelid heavy-chain-only antibodies (HcAbs are known to target epitopes that are less immunogenic to classical IgG and, due to their small size and protruding antigen-binding loop, able to reach and recognize cryptic, conformational epitopes which are inaccessible to conventional antibodies. The variable heavy chain (VHH domain is the antigen-binding site of camelid HcAbs, the so called Nanobody, which represents the smallest known (15 kDa intact, native antigen-binding fragment. In this study, we have used the Nanobody technology, an approach new to malaria research, to generate small and functional antibody fragments recognizing unique epitopes broadly distributed on VAR2CSA.

  1. Studies with /sup 15/N-lysine in colostomized hens. 6. /sup 15/N incorporation into the basic amino acids of liver, kidneys, flesh, bones and the remaining body as well as /sup 15/N balance

    Energy Technology Data Exchange (ETDEWEB)

    Hennig, A.; Gruhn, K. (Karl-Marx-Universitaet, Leipzig (German Democratic Republic))

    1984-10-01

    3 colostomized laying hybrides received 91.40 mg L-lysine-/sup 15/N-excess (/sup 15/N') each over a period of 4 days in a metabolism experiment with /sup 15/N-lysine. After another 4 days, during which the hens received the same rations supplemented by commercial L-lysine, the animals were butchered and divided into individual fractions. After hydrochloric hydrolysis of organs and tissues the heavy nitrogen of lysine, histidine and arginine were separated, quantitatively evaluated, processed and measured with an emission spectrometer. Atom-% /sup 15/N' on an average amounted to 0.20 in the liver, 0.16 in the kidneys, 0.06 in the flesh and 0.05 in the bones. Of the rediscovered /sup 15/N' applied, feces contained 8.1 %, urine 18.3 %, the eggs 24.3 %, the blood 4.9 %, the flesh 20.5 %, the bones 5.2 %, the gastrointestinal tract with its contents 4.5 %, the liver 3.5 %, the kidneys 0.9 %, the reproductive organs 3.7 %, and the rest 6.1 %. The quota of rediscovery of the /sup 15/N' applied was 95.7 %. 62 % of the total /sup 15/N' was rediscovered in eggs, body and feces as lysine /sup 15/N'. There was significantly more /sup 15/N' in all arginine fractions than in histidine. The quota of the lysine-/sup 15/N' of the total /sup 15/N' differed considerably in the fractions: < 40 % bones and blood; 48-56 % gastrointestinal tract, feces, oviduct, kidneys; 62-63 % remaining ovary, rest; 69-71 % eggs, flesh, liver. It could be proved that the ..cap alpha..-amino group of lysine is to a large extent incorporated into other amino acids. Further proof that the amino acid metabolism proceeds in two phases was submitted, i.e. higher amounts of amino acids previously deposited in the body are used for egg synthesis.

  2. Willingness to disclose child maltreatment: CSA vs other forms of child abuse in relation to gender.

    Science.gov (United States)

    Lev-Wiesel, Rachel; First, Maya

    2018-02-22

    The aim of the study was to examine the role of gender in willingness to disclose childhood sexual abuse (CSA) compared to other forms of abuse (physical, emotional and neglect) in young adolescents. Willingness was examined through two terms: reluctance- the level of unwillingness or disinclination to disclose, and urge-the need to share in order to get rid of unbearable feelings. The sample consisted of 3,156 boys (n = 1,544) and girls (n = 1,612) between the ages of 11-16 who reported having been abused at least once during their life. Participants were divided into three groups: experiencing other than CSA, sexual abuse with no physical contact, and sexual abuse with physical contact. Regarding measures, a self-report questionnaire incorporating the following instruments was administered: Demographics, the Juvenile Victimization Questionnaire (JVQ), and the Disclosure of Trauma Questionnaire (DTQ). Study results indicated that CSA victims were more reluctant to disclose than victims of other than CSA forms of abuse. The more severe the CSA (physical contact) the lower was the willingness to disclose. Boys were more reluctant than girls to disclose sexual abuse whether or not it involved physical contact. Reluctance to disclose was positively associated with emotional reactions to disclosure while urge to talk was negatively correlated with emotional reactions to disclosure. Copyright © 2018. Published by Elsevier Ltd.

  3. The antibody response of pregnant Cameroonian women to VAR2CSA ID1-ID2a, a small recombinant protein containing the CSA-binding site

    DEFF Research Database (Denmark)

    Babakhanyan, Anna; Leke, Rose G F; Salanti, Ali

    2014-01-01

    antigens, malarial antigens, or microbes. Currently, ID1-ID2a is a leading vaccine candidate, since it binds to the CSA with the same affinity as the full-length molecule and elicits binding-inhibitory antibodies in animals. Further studies are needed to determine if the presence of naturally acquired...... cross-reactive antibodies in women living in malaria endemic countries will alter the response to ID1-ID2a following vaccination with ID1-ID2a....

  4. High avidity antibodies to full-length VAR2CSA correlate with absence of placental malaria

    DEFF Research Database (Denmark)

    Tutterrow, Yeung Lo; Salanti, Ali; Avril, Marion

    2012-01-01

    VAR2CSA mediates sequestration of Plasmodium falciparum-infected erythrocytes in the placenta, increasing the risk of poor pregnancy outcomes. Naturally acquired antibodies (Ab) to placental parasites at delivery have been associated with improved pregnancy outcomes, but Ab levels and how early...... in pregnancy Ab must be present in order to eliminate placental parasites before delivery remains unknown. Antibodies to individual Duffy-binding like domains of VAR2CSA have been studied, but the domains lack many of the conformational epitopes present in full-length VAR2CSA (FV2). Thus, the purpose...... of this study was to describe the acquisition of Ab to FV2 in women residing in high and low transmission areas and determine how Ab levels during pregnancy correlate with clearance of placental parasites. Plasma samples collected monthly throughout pregnancy from pregnant women living in high and low...

  5. Electrical conductivity retention and electrochemical activity of CSA doped graphene/gold nanoparticle@ polyaniline composites

    Directory of Open Access Journals (Sweden)

    Md. Akherul Islam

    2016-08-01

    Full Text Available This paper reports the synthesis of CTAB mediated CSA doped PANI and GN/GNP@ PANI composite nanofibers. The as synthesized composite nanofibers were examined by TEM, SEM, XRD, Raman spectroscopy; UV–visible diffused reflectance spectroscopy and TGA. The CTAB mediated CSA doped composite nanofibers showed 59% higher DC electrical conductivity at ambient temperature than that of PANI, which might be due to the enhancement in the mobility of the charge carriers and reduction in hopping distance in the composite system. The CTAB mediated CSA doped composite nanofibers compared to PANI was observed to be showing enhanced DC electrical conductivity retention after various cycles of heating, suggesting an enhancement in thermal stability of the composite structure, which could be attributed to the synergistic effect of GN, GNP and PANI. Additionally, the composite nanofibers showed greater electrochemical activity and better capacitive performance and reduced optical bandgap than that of PANI.

  6. Doses from aquatic pathways in CSA-N288.1: deterministic and stochastic predictions compared

    International Nuclear Information System (INIS)

    Chouhan, S.L.; Davis, P.

    2002-04-01

    The conservatism and uncertainty in the Canadian Standards Association (CSA) model for calculating derived release limits (DRLs) for aquatic emissions of radionuclides from nuclear facilities was investigated. The model was run deterministically using the recommended default values for its parameters, and its predictions were compared with the distributed doses obtained by running the model stochastically. Probability density functions (PDFs) for the model parameters for the stochastic runs were constructed using data reported in the literature and results from experimental work done by AECL. The default values recommended for the CSA model for some parameters were found to be lower than the central values of the PDFs in about half of the cases. Doses (ingestion, groundshine and immersion) calculated as the median of 400 stochastic runs were higher than the deterministic doses predicted using the CSA default values of the parameters for more than half (85 out of the 163) of the cases. Thus, the CSA model is not conservative for calculating DRLs for aquatic radionuclide emissions, as it was intended to be. The output of the stochastic runs was used to determine the uncertainty in the CSA model predictions. The uncertainty in the total dose was high, with the 95% confidence interval exceeding an order of magnitude for all radionuclides. A sensitivity study revealed that total ingestion doses to adults predicted by the CSA model are sensitive primarily to water intake rates, bioaccumulation factors for fish and marine biota, dietary intakes of fish and marine biota, the fraction of consumed food arising from contaminated sources, the irrigation rate, occupancy factors and the sediment solid/liquid distribution coefficient. To improve DRL models, further research into aquatic exposure pathways should concentrate on reducing the uncertainty in these parameters. The PDFs given here can he used by other modellers to test and improve their models and to ensure that DRLs

  7. Fate of [15N]glycine in peat as determined by 13C and 15N CP-MAS NMR spectroscopy

    International Nuclear Information System (INIS)

    Benzing-Purdie, L.M.; Cheshire, M.V.; Williams, B.L.; Sparling, G.P.; Ratcliffe, C.I.; Ripmeester, J.A.

    1986-01-01

    Peat samples, nonsterile, sterilized by γ irradiation or autoclaving, were incubated with [ 15 N]glycine for a period of 6 months. The 13 C NMR data showed the established trend of increased humification with decreasing particle size and that autoclaving had significantly disturbed the humification-particle size distribution. The 15 N CP-MAS NMR spectra showed the presence of [ 15 N]glycine in all fractions after incubation. 15 NH 4 + , a result of either biological or chemical deamination, was one of the main products in the nonsterile peat series. The 15 N spectra also showed resonances corresponding to amine, secondary amide, and pyrrole-type nitrogen and the presence of glycine derivatives and melanoidins. The results presented give the first spectroscopic evidence of the possible involvement of the Maillard reaction in the humification process

  8. Studies with /sup 15/N-Lysine in colostomized hens. 4. Incorporation of lysine /sup 15/N into various amino acids of yolk and egg white

    Energy Technology Data Exchange (ETDEWEB)

    Gruhn, K.; Henning, A. (Karl-Marx-Universitaet, Leipzig (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin)

    1984-01-01

    Each of 3 colostomized laying hens received per os 0.2% L-lysine with 48 atom-% /sup 15/N excess (/sup 15/N') labelled in ..cap alpha..-position in addition to a pelleted laying hen ration of 120 g over a period of 4 days. On the following 4 days they received equal amounts of unlabelled lysine. The eggs laid during the 8 days of the experiment were separated into the egg white, the yolk and the eggshell, and the total and heavy nitrogen in the individual fractions were determined. Above that, 17 amino acids and their atom-%/sup 15/N' were determined in the 19 samples of the white and yolk of egg. Of the total /sup 15/N' from the lysine fed in the 4 days, 10.1% were found in the yolk, 10.5% in the egg white and 1.1% in the eggshells of the eggs laid during the 8 days of the experiment. 85% of the total amino acid /sup 15/N' of the yolk and 86% of the egg white detected to be lysine /sup 15/N'. The /sup 15/N' amount of the other 16 amino acids was mainly concentrated in the two acid and basic amino acids. Approximately 50% of the non-lysine /sup 15/N' in the egg are contained in aspartic acid, glutamic acid, histidine and arginine. A very low incorporation of the labelled lysine only could be detected in the aromatic and sulphur-containing amino acids from both the yolk and the egg white 43% of the /sup 15/N' was detected in the 10 essential and semi-essential (except lysine) and 57% in the 6 non-essential amino acids of the yolk and 52% and 48% resp. of the egg white. One can summarise that the incorporation of /sup 15/N' into the egg shows the same development as that of the labelled amino acids of the wheat protein and that 15% of the lysine /sup 15/N' could be detected in the 16 other amino acids.

  9. Engineering application of in-core fuel management optimization code with CSA algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhihong; Hu, Yongming [INET, Tsinghua university, Beijing 100084 (China)

    2009-06-15

    PWR in-core loading (reloading) pattern optimization is a complex combined problem. An excellent fuel management optimization code can greatly improve the efficiency of core reloading design, and bring economic and safety benefits. Today many optimization codes with experiences or searching algorithms (such as SA, GA, ANN, ACO) have been developed, while how to improve their searching efficiency and engineering usability still needs further research. CSA (Characteristic Statistic Algorithm) is a global optimization algorithm with high efficiency developed by our team. The performance of CSA has been proved on many problems (such as Traveling Salesman Problems). The idea of CSA is to induce searching direction by the statistic distribution of characteristic values. This algorithm is quite suitable for fuel management optimization. Optimization code with CSA has been developed and was used on many core models. The research in this paper is to improve the engineering usability of CSA code according to all the actual engineering requirements. Many new improvements have been completed in this code, such as: 1. Considering the asymmetry of burn-up in one assembly, the rotation of each assembly is considered as new optimization variables in this code. 2. Worth of control rods must satisfy the given constraint, so some relative modifications are added into optimization code. 3. To deal with the combination of alternate cycles, multi-cycle optimization is considered in this code. 4. To confirm the accuracy of optimization results, many identifications of the physics calculation module in this code have been done, and the parameters of optimization schemes are checked by SCIENCE code. The improved optimization code with CSA has been used on Qinshan nuclear plant of China. The reloading of cycle 7, 8, 9 (12 months, no burnable poisons) and the 18 months equilibrium cycle (with burnable poisons) reloading are optimized. At last, many optimized schemes are found by CSA code

  10. Primary amine/CSA ion pair: A powerful catalytic system for the asymmetric enamine catalysis

    KAUST Repository

    Liu, Chen

    2011-05-20

    A novel ion pair catalyst containing a chiral counteranion can be readily derived by simply mixing cinchona alkaloid-derived diamine with chiral camphorsulfonic acid (CSA). A mixture of 9-amino(9-deoxy)epi-quinine 8 and (-)-CSA was found to be the best catalyst with matching chirality, enabling the direct amination of α-branched aldehydes to proceed in quantitative yields and with nearly perfect enantioselectivities. A 0.5 mol % catalyst loading was sufficient to catalyze the reaction, and a gram scale enantioselective synthesis of biologically important α-methyl phenylglycine has been successfully demonstrated. © 2011 American Chemical Society.

  11. Growth, Water Use, and Nitrate-15N Uptake of Greenhouse Tomato as Influenced by Different Irrigation Patterns, 15N Labeled Depths, and Transplant Times

    OpenAIRE

    Hou, Maomao; Jin, Qiu; Lu, Xinyu; Li, Jiyu; Zhong, Huizhen; Gao, Yue

    2017-01-01

    Increasing water use efficiency and reducing nitrogen pollutant discharge are important tasks for modern agriculture. To evaluate the effect of alternate partial root-zone irrigation (APRI) on tomato plant growth, water use efficiency and nitrate-15N uptake, an experiment was conducted from June to December in 2014 under greenhouse condition in northern China. The experiment contained two irrigation patterns [APRI and conventional irrigation (CI)], two 15N labeled depths in soil (10 and 50 cm...

  12. Molecular dissection of placental malaria protein VAR2CSA interaction with a chemo-enzymatically synthesized chondroitin sulfate library

    DEFF Research Database (Denmark)

    Sugiura, Nobuo; Clausen, Thomas Mandel; Shioiri, Tatsuasa

    2016-01-01

    Placental malaria, a serious infection caused by the parasite Plasmodium falciparum, is characterized by the selective accumulation of infected erythrocytes (IEs) in the placentas of the pregnant women. Placental adherence is mediated by the malarial VAR2CSA protein, which interacts......-sulfated CSA dodecasaccharide, and found that a highly sulfated CSA eicosasaccharide is a more potent inhibitor of rVAR2 binding than the dodecasaccharides. These results suggest that CSA derivatives may potentially serve as targets in therapeutic strategies against placental malaria....

  13. Utilization of 15N-labelled urea in laying hens. 7

    International Nuclear Information System (INIS)

    Gruhn, K.

    1987-01-01

    3 colostomized laying hybrids received 1% 15 N-labelled urea with 96.06 atom-% 15 N excess ( 15 N') with a commercial ration over a period of 6 days. After the application of the same ration with unlabelled urea on the following 2 days the animals were butchered. In the muscles of breast, legs and heart, the labelling of total nitrogen and the incorporation of urea 15 N' into 15 amino acids of the 3 different kinds of muscles were ascertained. On average, significant differences could be ascertained between the atom-% 15 N of the muscles was 0.25 and 0.34 atom-%, resp.; that of the cardial proteins 0.71 atom-% 15 N'. The incorporation of urea 15 N into the basic amino acids is low and varies both between the kinds of muscles and between the amino acids. On average the highest level of labelling was found among the essential amino acids valine, isoleucine and leucine; the average atom-% 15 N' for the muscles of the breast is 0.13, of the leg 0.17, and of the heart 0.27; the 15 N' quota of branched Chain amino acids in the total 15 N' of the respective muscle is accordingly 6.0%, 5.0% and 4.5%. The non-essential amino acids, particularly glutamic acid, are more highly labelled in the muscles than the essential ones. A 15 N' for glutamic acid of 0.24 atom-% in the breast muscles, of 0.27 atom-% in those of the legs and of 0.64 atom-% in the heart muscle could be detected. The average quota of the 15 N' of these acid amino acids in the 15 N' for breast, leg and heart muscles is 7.4, 6.2 and 6.7, resp. The quota of the 15 N' in the 6 non-essential amino acids in the total 15 N' in all 3 kinds of muscles is approximately two thirds and in the 9 essential ones one third of the total 15 N'. Although the results show that there is a certain incorporation of 15 N' from urea into the amino acids of the muscle proteins, their contribution to meeting the demands is irrelevant. (author)

  14. [15N-flow after in sacco incubation and feeding of sheep and goats with untreated wheat straw or straw treated with 15N horse urine].

    Science.gov (United States)

    Schubert, R; Flachowsky, G; Bochröder, B

    1994-01-01

    Chopped wheat straw was homogeneously mixed with urine of horses (5.75 gN per 1, 16.88 atom-% 15N-excess) and airtightly stored in plastic containers for 6 months. Three rumen fistulated sheep and goats each were fed with untreated or urine treated straw. Concentrate was added to straw. Untreated and urine treated straw were given in nylon bags and incubated in the rumen of sheep and goats for 1, 3, 6, 12, 24, 48 and 72 hours. A three compartment exponential function was used to fit the measurements of 15N-excess and 15N-amount of bag content. The curves and the calculated partial Y-values of the three compartments show the inflow and outflow of 15N into or from the bags and allow conclusions about the binding of urine N. Most N of urine was not compactly bound by straw during storage. Primarily microbial N was attached to the straw in the rumen. About 6% of urine N were bound more compact to the straw. Similar curves were calculated for 15N-excess and 15N-amount of nylon bags. The curves allow conclusions about tracer flows without quantitative knowledge. There were no significant differences between animal species.

  15. 15N2 Fixation and H2 Evolution by Six Species of Tropical Leguminous Trees 1

    Science.gov (United States)

    van Kessel, Christopher; Roskoski, Joann P.; Wood, Timothy; Montano, Jorge

    1983-01-01

    The C2H4/15N2 and H2/15N2 ratios for six species of tropical leguminous trees are reported. C2H4/15N2 ratios ranged from 2.4 to 4.7; values for the H2/15N2 ratios were between 0.6 and 1.4. Relative efficiency values, based on C2H2 reduction, 15N incorporation, and H2 evolution during 15N incorporation varied between 0.68 and 0.84 for the six species. Overall, approximately 30% of the electron flow through nitrogenase was used for H2 evolution. PMID:16663109

  16. Investigation into endogenous N metabolism in 15N-labelled pigs. 1

    International Nuclear Information System (INIS)

    Bergner, H.; Bergner, U.; Adam, K.

    1984-01-01

    4 male castrated pigs (55-65 kg) either received a wheat-fish meal diet (1 and 2) or a wheat-horse bean diet (3 and 4) without straw meal supplement (1 and 3) or with a supplement of 20% dry matter (2 and 4). In order to investigate whether a 15 N labelling of the pigs is also possible with a protein excess in the ration, the animals received 24.8 g (1 and 2) and 11.6 g crude protein/kg/sup 0.75/ live weight (3 and 4). During a 10-day 15 N-labelling 385 mg 15 N excess ( 15 N') per kg/sup 0.75/ were applied with 15 N labelling the following quotas of the applied 15 N amount were incorporated: 1 = 10.2%, 2 = 7.2%, 3 = 18.7%, 4 = 14.4%. 15 N excretion in both TCA fractions of feces showed a highly significant positive correlation to the increasing content of crude fibre in the 4 diets. The immediate 15 N incorporation into the TCA-precipitable fraction of feces proves that 15 N enters the large intestine endogenously and serves bacterial protein synthesis. 3 days after the last 15 application the pigs were killed. The values of atom-% 15 N' were determined in the TCA-precipitable blood plasma and in the TCA-precipitable fraction of the liver. The other examined organs and tissues showed smaller differences between the test animals. The results show that the 15 N labelling of tissues and organs of pigs is also possible at a high level of protein supply by means of an oral application of [ 15 N] ammonia salts. (author)

  17. Investigation of the metabolism of colostomized laying hens with 15N-labelled wheat. 5

    International Nuclear Information System (INIS)

    Gruhn, K.

    1980-01-01

    In an experiment with 3 colostomized laying hybrids each animal received 80 g pelleted mixed feed and 40 g 15 N-labelled wheat with 20.13 atom-% 15 N excess ( 15 N') over a period of four days. On the following four days the hens received rations composed in the same way with unlabelled wheat, however in the tissues and organs of the slaughtered hens 15 N' was determined in the total N and the amino acids lysine, histidine and arginine in both the segments of the gastro intestinal tract and in its content. The amount of 15 N' stomach, small intestine and colon was 43.7%, 27.2% and 29.1%, respectively. The tissue of the small intestine contained, on an average, the highest 15 N' in lysine of all the basic amino acids. It was 0.82 atom-% 15 N' for lysine, 0.55% for histidine and 0.63% for arginine. The percentage of the 15 N' of the basic amino acids from the corresponding total 15 N' amount of the charges was 20.5% in the contents of the gastrointestinal tract, 28.0% in the stomach tissue and in the tissues of the small intestine 24.4% of the cecum 21.5% and of the rectum 25.7%. (author)

  18. Effects of growth and change of food on the δ15N in marine fishes

    International Nuclear Information System (INIS)

    Kasamatsu, Fujio; Sato, Rie; Park, Kwang Lai

    1998-01-01

    Information is limited concerning variation of the δ 15 N with growth in marine organisms and consequently the effect of growth of marine biota on the δ 15 N is not yet well understood. The δ 15 N in 26 species of marine fishes taken from Japanese coastal waters together with 4664 stomach contents of these fishes were examined to investigate the effects of food habits and growth on the δ 15 N. The mean δ 15 N for two species that fed mainly on large-size fishes and six species that fed mainly on small-size fishes were 14.5±1.0per mille and 12.8±0.7per mille, respectively. For five species that fed mainly on decapod crustaceans, two species that fed mainly on zooplankton, and three species that fed mainly on benthos (mainly Polychaeta), the δ 15 N were 13.0±0.7, 9.7±0.9, and 12.2±1.2per mille, respectively. The mean δ 15 N in the species whose prey were mainly fish or decapod crustaceans was about 3-5per mille higher than the species whose prey was mainly zooplankton. Within the four species that shift their food habits with growth to higher trophic level, the δ 15 N significantly increased with growth in one species (Pacific cod), while not significant increase in the δ 15 N with growth in the remaining species. (author)

  19. Stable isotope sup 15 N-urea and clinical research in nephrology

    Energy Technology Data Exchange (ETDEWEB)

    Sugino, Nobuhiro; Arai, Junko; Akimoto, Mitsuko; Miwa, Toichiro; Takuma, Takehide (Tokyo Women' s Medical Coll. (Japan))

    1990-08-01

    Stable isotope {sup 15}N-compound, {sup 15}N-urea, is useful marker to investigate nitrogen metabolism in clinical nephrology, particularly in chronic renal failure or dialysis. {sup 15}N-urea incorporation into plasma albumin in addition to plasma {sup 15}N disappearance was studied in 6 patients with endstage chronic renal failure. As a result, only minor fraction of administered {sup 15}N-urea was incorporated into albumin in this study. In addition, it was also confirmed that high energy diet may promote protein synthesis through {sup 15}N incorporation to plasma amino acids, such as alanine, in these patients with low protein meal. Therefore, administration of {sup 15}N-compound to human subjects may contribute to provide us the important informations on nitrogen metabolism. For instance, urea kinetics are described in the endstage chronic renal failure in this review. However, less expensive {sup 15}N-compounds should be provided and more simple but accurate measurement of {sup 15}N activity should be developed for the further clinical application of the stable isotope. (author).

  20. [Hematologic response predictor factors in adults with myelodysplastic syndromes (SMD) treated with cyclosporin A (CSA)].

    Science.gov (United States)

    Zamora-Pérez, Elia; López-Karpovitch, Xavier

    2015-01-01

    Myelodysplastic syndromes (MDS) are clonal diseases of hematopoietic cells. The International Prognostic Scoring System (IPSS) is the risk scale most employed in MDS. Cyclosporin A (CsA) has been used in the treatment of cytopenias in MDS. To evaluate hematologic response and identify response predictive factors in adults with MDS treated with CsA. Patients with MDS diagnosed according World Health Organization (WHO) classification were recruited from January 1997 to June 2012. All patients were classified with IPSS, IPSS revised (IPSS-R),WHO Prognostic Scoring System (WPSS), and WPSS revised (WPSS-R) risk scales. Cyclosporin A was administered orally at a dose of 5 mg/kg/day. Hematologic response was evaluated following the International Working Group for MDS (2006 version) criteria. Inclusion criteria were met by 32 patients. Median age was 56.5 years, with a median follow-up of 3.1 years. Hematologic response was 56.2% and erythrocyte independence transfusion was found in 42.9% of patients. Age,hemoglobin level, and WPSS at diagnosis were independent predictive factors for CsA response. Survival was longer in responder than in nonresponder CsA patients (p=0.06). Cyclosporin A induced hematologic response in >50% of patients with MDS aged <57 years, with Hb<8 g/dl and low WPSS at diagnosis.

  1. Boys and CSA Prevention: Issues Surrounding Gender and Approaches for Prevention

    Science.gov (United States)

    Scholes, Laura; Jones, Christian; Nagel, Michael

    2014-01-01

    Freda Briggs (2007), a leader in the field of child protection in Australia continues to raise concerns about the vulnerability and victimisation of boys that she believes is substantially under-recognised. She argues that boys have not been well supported by child sexual abuse (CSA) prevention programs with child protection curriculum not yet…

  2. Structural Insight into Epitopes in the Pregnancy-Associated Malaria Protein VAR2CSA

    DEFF Research Database (Denmark)

    Andersen, P; Nielsen, MA; Resende, M

    2008-01-01

    Pregnancy-associated malaria is caused by Plasmodium falciparum malaria parasites binding specifically to chondroitin sulfate A in the placenta. This sequestration of parasites is a major cause of low birth weight in infants and anemia in the mothers. VAR2CSA, a polymorphic multi-domain protein o...

  3. A VAR2CSA:CSP conjugate capable of inducing dual specificity ...

    African Journals Online (AJOL)

    A VAR2CSA:CSP conjugate capable of inducing dual specificity antibody responses. Matondo Sungwa1, Thrane Susan2, Janitzek Christoph Mikkel2, Kavishe Reginald Adolph1,. Mwakalinga Steven Boniface1, Theander Thor Grundtvig2, Salanti Ali2,. Nielsen Morten Agertoug2, Sander Adam Frederik2. 1. Kilimanjaro ...

  4. Utilizing nanobody technology to target non-immunodominant domains of VAR2CSA

    DEFF Research Database (Denmark)

    Ditlev, Sisse B; Florea, Raluca; Nielsen, Morten A

    2014-01-01

    called Nanobody, which represents the smallest known (15 kDa) intact, native antigen-binding fragment. In this study, we have used the Nanobody technology, an approach new to malaria research, to generate small and functional antibody fragments recognizing unique epitopes broadly distributed on VAR2CSA....

  5. Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA

    DEFF Research Database (Denmark)

    Resende, Mafalda; Nielsen, Morten A.; Dahlbaeck, Madeleine

    2008-01-01

    Background: Pregnancy malaria is caused by Plasmodium falciparum-infected erythrocytes binding the placental receptor chondroitin sulfate A (CSA). This results in accumulation of parasites in the placenta with severe clinical consequences for the mother and her unborn child. Women become resistan...

  6. Different effects of CSA and CSB deficiency on sensitivity to oxidative DNA damage.

    NARCIS (Netherlands)

    H. de Waard (Harm); J. de Wit (Jan); J.-O. Andressoo (Jaan-Olle); C.T.M. van Oostrom (Conny); B. Riis (Bente); A. Weimann (Allan); H.E. Poulsen (Henrik); H. van Steeg (Harry); J.H.J. Hoeijmakers (Jan); G.T.J. van der Horst (Gijsbertus)

    2004-01-01

    textabstractMutations in the CSA and CSB genes cause Cockayne syndrome, a rare inherited disorder characterized by UV sensitivity, severe neurological abnormalities, and progeriod symptoms. Both gene products function in the transcription-coupled repair (TCR) subpathway of nucleotide excision repair

  7. Structural and functional insight into how the Plasmodium falciparum VAR2CSA protein mediates binding to chondroitin sulfate A in placental malaria

    DEFF Research Database (Denmark)

    Clausen, Thomas M; Christoffersen, Stig; Dahlbäck, Madeleine

    2012-01-01

    that the CSA-binding DBL2X domain is situated in the center of the structure. Mutating classic sulfate-binding sites in VAR2CSA, along with testing dependence of ionic interactions, suggest that the CSA binding is not solely dependent on the sulfated CSA structure. Based on these novel PfEMP1 structure......Malaria is a major global health problem. Pregnant women are susceptible to infection regardless of previously acquired immunity. Placental malaria is caused by parasites capable of sequestering in the placenta. This is mediated by VAR2CSA, a parasite antigen that interacts with chondroitin sulfate...... A (CSA). One vaccine strategy is to block this interaction with VAR2CSA-specific antibodies. It is a priority to define a small VAR2CSA fragment that can be used in an adhesion blocking vaccine. In this, the obvious approach is to define regions of VAR2CSA involved in receptor binding. It has been shown...

  8. The relationship between passive stiffness and evoked twitch properties: the influence of muscle CSA normalization

    International Nuclear Information System (INIS)

    Ryan, E D; Thompson, B J; Sobolewski, E J; Herda, T J; Costa, P B; Walter, A A; Cramer, J T

    2011-01-01

    Passive stiffness measurements are often used as a clinical tool to examine a muscle's passive lengthening characteristics. The purpose of this study was to examine the relationship between passive stiffness and evoked twitch properties prior to and following normalization of passive stiffness to muscle cross-sectional area (CSA). Ten healthy volunteers (mean ± SD age = 23 ± 3 year) performed passive range of motion, evoked twitch, and muscle CSA assessments of the plantar flexor muscles. Passive stiffness was determined from the slope of the final 5° of the angle–torque curve. Peak twitch torque (PTT) and rate of torque development (RTD) were determined via transcutaneous electrical stimulation, and muscle CSA was assessed using a peripheral quantitative computed tomography scanner. Pearson product moment correlation coefficients (r) were used to assess the relationships between passive stiffness and PTT and RTD and normalized passive stiffness (passive stiffness . muscle CSA −1 ) and PTT and RTD. Significant positive relationships were observed between passive stiffness and PTT (P = 0.003, r = 0.828) and RTD (P = 0.003, r = 0.825). There were no significant relationships between normalized passive stiffness and PTT (P = 0.290, r = 0.372) or RTD (P = 0.353, r = 0.329) demonstrating that stiffness did not account for a significant portion of the variance in twitch properties. Passive stiffness was largely influenced by the amount of muscle tissue in this study. Future studies that examine muscle stiffness and its relationship with performance measures, among different populations, and following various interventions may consider normalizing stiffness measurements to muscle CSA

  9. Baculovirus-expressed constructs induce immunoglobulin G that recognizes VAR2CSA on Plasmodium falciparum-infected erythrocytes

    DEFF Research Database (Denmark)

    Barfod, Lea; Nielsen, Morten A; Turner, Louise

    2006-01-01

    We raised specific antisera against recombinant VAR2CSA domains produced in Escherichia coli and in insect cells. All were reactive in enzyme-linked immunosorbent assay, but only insect cell-derived constructs induced immunoglobulin G (IgG) that was reactive with native VAR2CSA on the surface...

  10. Differential induction of functional IgG using the Plasmodium falciparum placental malaria vaccine candidate VAR2CSA

    DEFF Research Database (Denmark)

    Pinto, Vera V; Ditlev, Sisse B; Jensen, Kamilla E

    2011-01-01

    and chondroitin sulfate A (CSA) in the placental intervillous space and lack of protective antibodies. PM impairs fetal development mainly by excessive inflammation processes. After infections during pregnancy women acquire immunity to PM conferred by antibodies against VAR2CSA. Ideally, a vaccine against PM...

  11. Identification of a Major Dimorphic Region in the Functionally Critical N-Terminal ID1 Domain of VAR2CSA

    DEFF Research Database (Denmark)

    Doritchamou, Justin; Sabbagh, Audrey; Jespersen, Jakob S

    2015-01-01

    The VAR2CSA protein of Plasmodium falciparum is transported to and expressed on the infected erythrocyte surface where it plays a key role in placental malaria (PM). It is the current leading candidate for a vaccine to prevent PM. However, the antigenic polymorphism integral to VAR2CSA poses a ch...

  12. Insight into Antigenic Diversity of VAR2CSA-DBL5 epsilon Domain from Multiple Plasmodium falciparum Placental Isolates

    DEFF Research Database (Denmark)

    Gnidehou, Sedami; Jessen, Leon Ivar; Gangnard, Stephane

    2010-01-01

    domains. These two observations combined point to the importance of identifying VAR2CSA sequence variation, which facilitate parasitic evasion or subversion of host immune response. Highly conserved domains of VAR2CSA such as DBL5e are likely to contain conserved epitopes, and therefore do constitute...

  13. Utilization of 15N-labelled urea in laying hens. 8

    International Nuclear Information System (INIS)

    Gruhn, K.; Graf, H.

    1987-01-01

    3 colostomized laying hybrids received orally with a conventional ration 1% urea with 96.06 atom-% 15 N excess ( 15 N') over a period of 6 days. In the period of the experiment every hen consumed 2.87 g 15 N'. After another 2 days, on which they received conventional feed urea, the animals were butchered. 15 N' was determined in the total N and in 15 amino acids of the oviduct. Of the 15 amino acids the labelling of glutamic acid, glycine and serine was highest and on average amounted to 0.80, 0.66 and 0.67 atom-% 15 N', resp. In lysine and arginine only 0.10 and 0.11 atom-% 15 N' could be detected. The amino acid N with natural isotopic frequency amounted to a quarter for the basic amino acids, a tenth for the branched chain ones and for the non-essential ones (glutamic acid, aspartic acid, serine, glycine, alanine, proline) a third of the total oviduct 14 N. The average quota of 15 N' is only 3.6%, that of the branched chain amino acids 4.5 and that of the non-essential ones 21.1%. Consequently, the 15 N' of the urea is mainly used for the synthesis of the non-essential amino acids of the oviduct. (author)

  14. Utilization of 15N-labelled urea in laying hens. 2

    International Nuclear Information System (INIS)

    Gruhn, K.; Zander, R.

    1985-01-01

    In an N metabolism experiment 3 colostomized laying hybrids received 2870 mg 15 N excess ( 15 N') per animal in 6 days in the form of urea with their conventional feed rations. During the 8-day experiment the 21 eggs laid were separated into egg-shell, white of egg and yolk. Weight, N content and 15 N' of the individual fractions of the eggs were determined. On an average 4.6% of the heavy nitrogen was in the egg-shells, 50% in the white of egg and 45.5% in the yolk. 2.8%, 4.5% and 5.5% (hens 1 - 3) of the 15 N' consumed were detected in the eggs. The maximum 15 N' output in the white of egg was reached on the 6th day, whereas 15 N' output in the yolk showed a nearly linear increase in the time of the experiment. The results show that labelled nitrogen from urea is incorporated into the egg to a lower degree than after the feeding of 15 N-labelled proteins and that the development of its incorporation into the white of egg and the yolk differ from that after the feeding of 15 N-labelled native proteins. (author)

  15. Disturbance and topography shape nitrogen availability and ä15N over long-term forest succession

    Science.gov (United States)

    Steven S. Perakis; Alan J. Tepley; Jana E. Compton

    2015-01-01

    Forest disturbance and long-term succession towards old-growth are thought to increase nitrogen (N) availability and N loss, which should increase soil ä15N values. We examined soil and foliar patterns in N and ä15N, and soil N mineralization, across 800 years of forest succession in a topographically complex montane...

  16. Disturbance and topography shape nitrogen availability and δ15N over long-term forest succession

    Science.gov (United States)

    Forest disturbance and long-term succession can promote open N cycling that increases N loss and soil δ15N values. We examined soil and foliar patterns in N and δ15N, and soil N mineralization, across a topographically complex montane forest landscape influenced by human logging ...

  17. Nitrogen cycling in a forest stream determined by a 15N tracer addition

    Science.gov (United States)

    Patrick J. Mullholland; Jennifer L. Tank; Diane M. Sanzone; Wilfred M. Wollheim; Bruce J. Peterson; Jackson R. Webster; Judy L. Meyer

    2000-01-01

    Nitrogen uptake and cycling was examined using a six-week tracer addition of 15N-labeled ammonium in early spring in Waer Branch, a first-order deciduous forest stream in eastern Tennessee. Prior to the 15N addition, standing stocks of N were determined for the major biomass compartments. During and after the addition,

  18. Nitrogen-15-labeled deoxynucleosides. 3. Synthesis of [3-15N]-2'-deoxyadenosine

    International Nuclear Information System (INIS)

    Rhee, Young-Sook; Jones, R.A.

    1990-01-01

    The synthesis of [3- 15 N]-labeled adenine has been reported by several groups. Each of these syntheses followed essentially the same route, in which the 15 N is introduced by nitration of 4-bromoimidazole under forcing conditions using [ 15 N]-HNO 3 . The authors have devised an alternate route which uses an azo coupling reaction for introduction of the 15 N and proceeds through the intermediacy of [5- 15 N]-labeled 5-aminoimidazole-4-carboxamide (AICA). An unrelated route to the [5- 15 N]-labeled 5-amino-imidazole ribonucleoside (AIRs) was recently reported. AICA is a versatile precursor, which is most commonly used for entry into the guanine or isoguanine families, although it is usually used as the AICA-riboside rather than the heterocycle itself. The authors have found that AICA also can be used for the adenine family by cyclization to hypoxanthine using diethoxymethyl acetate in DMF at reflux. Although these conditions are more vigorous than those required for cyclization of 4,5-diaminopyrimidines using this reagent, the reaction works well. In addition, they report high-yield enzymatic conversion of [3- 15 N]-adenine to [3- 15 N]-2'-deoxyadenosine

  19. Nitrogen processing in a tidal freshwater marsh: a whole ecosystem 15N labeling study

    NARCIS (Netherlands)

    Gribsholt, B.; Boschker, H.T.S.; Struyf, E.; Andersson, M.G.I.; Tramper, A.; de Brabandere, L.; van Damme, S.; Brion, N.; Meire, P.; Dehairs, F.; Middelburg, J.J.; Heip, C.H.R.

    2005-01-01

    We quantified the fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrientrich Scheldt River in a whole-ecosystem 15N labeling experiment. 15N-NH4+ was added to the floodwater entering a 3,477 14 m2 tidal marsh area, and marsh ammonium processing and

  20. Application of 15N amino acid absorption in chronic enteropathy and hepatic diseases in infants

    International Nuclear Information System (INIS)

    Culea, M.; Palibroda, N.; Chiriac, M.; Moldovan, Z.; Miu, N.

    1993-01-01

    The aim of this study was to estimate malabsorption status in humans using a 15 N stable isotope tracer technique. [ 15 N]-glycine, 98.98 atom %, was synthesized in our institute and was administered orally as a single bolus dose to twelve patients. Six of the 12 subjects studied were healthy and 6 were suspected of having malabsorption. Blood, urine and faecal samples were obtained, proteins in the samples were precipitated with sulphosalicylic acid (5%), the eluate was purified with Dowex 50W-X8 (40mm x 2mm column), and derivatised to form the trifluoroacetyl-butyl esters using standard techniques. Gas chromatographic separation was performed on a glass column 2m X 3mm i.d. packed with EGA 1% on Chromosorb W AW 80-100 mesh. An isotope dilution GC/MS method and Kjeldahl digestion followed by MS analysis of nitrogen gas was performed. 15 N isotopomer was used as internal standard. [ 15 N]-Gly elimination in faeces was compared with total 15 N elimination in faeces to distinguish artefacts caused by intestinal bacteria. Significant differences in the amount of [ 15 N]-Gly eliminated in urine and faeces between malabsorption and control patients were obtained. It was concluded that more emphasis should be given to the faeces data than to urine because 15 N elimination in urine is competitive with 15 N incorporation into protein. 12 refs, 4 figs, 4 tabs

  1. Measurement of nitrogen fertility of paddy field soil by the employment of 15N and productivity

    International Nuclear Information System (INIS)

    Koyama, Takeo

    1975-01-01

    After giving 15 N-nitrogenous fertilizer to a paddy field, the ratio of soil nitrogen to fertilizer nitrogen incorporated by rice plants was investigated by a tracer method. The nitrogen fertility of soil by employing 15 N fertilizer is expressed as N=M x S/F (N, soil nitrogen amount; M, fertilizer given; F, fertilizer nitrogen incorporated by plants; S, soil nitrogen incorporated by plants). The ratio of the incorporation of soil nitrogen to that of 15 N-labelled fertilizer nitrogen was measured by this method, and the influence of soil nitrogen and fertilizer nitrogen upon the productivity of rice was investigate. The mechanism of converting to organic matter in soil from 15 N-labelled fertilizer nitrogen was also observed. Further studies using 15 N is expected. (Kobatake, H.)

  2. Elastic and inelastic scattering of 15n ions by 11B at 84 MeV

    Directory of Open Access Journals (Sweden)

    A. T. Rudchik

    2014-09-01

    Full Text Available Angular distributions of the 11B + 15N elastic and inelastic scattering were measured at Elab (15N = 84 MeV. The data were analyzed within the optical model and coupled-reaction-channels method. The elastic and inelastic scattering, reorientations of 11B and 15N in ground and excited states as well as the important one- and two-step transfer reactions were included in the channels-coupling-scheme. The 11B + 15N optical potential parameters as well as deformation parameters of these nuclei were deduced. The contributions of one- and two-step transfers in the 11B + 15N elastic and inelastic scattering channels were estimated.

  3. Absorption and translocation of 15N in Japonica (Hinohikari) and Indica (Hadsaduri) rice varieties

    International Nuclear Information System (INIS)

    Islam, N.; Inagaki, S.; Chishaki, N.; Horiguchi, T.

    1997-01-01

    The absorption and translocation of 15 N-labeled nitrogen (N) applied as three N levels of ammonium nitrate at the stages of panicle initiation (PI) and heading (HD) were compared between a japonica rice variety (var. Hinohikari) and a tall indica rice variety (var. Hadsaduri) by growing them hydroponically. With the supply of low N level, 15 N absorption by the japonica variety was larger, but at medium and high N levels, the tall indica variety absorbed larger amounts of 15 N at both stages. However, the amount of 15 N partitioned to the panicles at maturity was considerably smaller in the indica variety, since dry matter allocation to the panicles was also smaller in this variety. The tall indica variety showed a considerable loss of 15 N from heading to maturity at the high N-level unlike the japonica variety. (author)

  4. Symbiotic nitrogen fixation in an arid ecosystem measured by sup 15 N natural abundance

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, G.V. (Univ. of New Mexico, Albuquerque (USA))

    1990-05-01

    Plants dependent on nitrogen fixation have an {sup 15}N abundance similar to the atmosphere, while non-nitrogen fixing plants usually are enriched in {sup 15}N and are similar to soil nitrogen values. The natural abundance of {sup 15}N in leaf tissues and soils was determined to evaluate symbiotic nitrogen fixation by several legumes and actinorhizal species in the Sevilleta Long-term Ecological Research area in central New Mexico. Comparison of {delta}{sup 15}N values for the legume Prosopis glandulosa (mesquite) to adjacent Atriplex canascens (fourwing saltbush) indicated that P. glandulosa obtained 66% of its nitrogen by fixation. The legume Hoffmanseggia jamesii was found to be utilizing soil nitrogen. The {delta}{sup 15}N values for the actinorhizal plants, Elaeagnus angustifolia and Cercocarpus montanus, while below values for soil nitrogen, did not differ from associated non-fixing plants.

  5. Using a macroalgal δ15N bioassay to detect cruise ship waste water effluent inputs

    International Nuclear Information System (INIS)

    Kaldy, James

    2011-01-01

    Highlights: → Green macroalgae exposed to nutrient solutions exhibited changes in tissue 15 N signatures. → Macroalgae exhibited no fractionation with NO 3 and slight fractionation with NH 4 . → Algae exposed to cruise ship waste water had increased tissue δ 15 N indicating a heavy N source. → Field bioassays exhibited decreased δ 15 N indicating isotopically light riverine δ 15 N-NO 3 was likely the dominant N source. → Algal bioassays could not detect a δ 15 N cruise ship waste water signal in this system. - Abstract: Green macroalgae bioassays were used to determine if the δ 15 N signature of cruise ship waste water effluent (CSWWE) could be detected in a small harbor. Opportunistic green macroalgae (Ulva spp.) were collected, cultured under nutrient depleted conditions and characterized with regard to N content and δ 15 N. Samples of algae were used in controlled incubations to evaluate the direction of isotope shift from exposure to CSWWE. Algae samples exposed to CSWWE exhibited an increase of 1-2.5 per mille in δ 15 N values indicating that the CSWWE had an enriched isotope signature. In contrast, algae samples exposed to field conditions exhibited a significant decrease in the observed δ 15 N indicating that a light N source was used. Isotopically light, riverine nitrogen derived from N 2 -fixing trees in the watershed may be a N source utilized by algae. These experiments indicate that the δ 15 N CSWWE signature was not detectable under the CSWWE loading conditions of this experiment.

  6. Residue-specific pK(a) determination of lysine and arginine side chains by indirect N-15 and C-13 NMR spectroscopy : Application to apo calmodulin

    NARCIS (Netherlands)

    Andre, Ingemar; Linse, Sara; Mulder, Frans A. A.

    2007-01-01

    Electrostatic interactions in proteins can be probed experimentally through determination of residue-specific acidity constants, We describe here triple-resonance NMR techniques for direct determination of lysine and arginine side-chain protonation states in proteins. The experiments are based on

  7. Analysis of carbon and nitrogen forms in soil fractions after the addition of 15N-compost by 13C and 15N nuclear magnetic resonance.

    Science.gov (United States)

    Tinoco, Pilar; Almendros, Gonzalo; González-Vila, Francisco J; Lankes, Ulrich; Lüdemann, Hans-Dietrich

    2004-08-25

    A quantitative laboratory assessment of the different C and N forms in soil humus fractions was carried out by incubation of a mineral substrate after the addition of (15)N-labeled compost. The experimental design included (i) preparation of the (15)N-labeled organic matter (city refuse compost, 640 g kg(-1) wheat straw and K(15)NO(3) composted for 80 days), (ii) a further 80 day incubation of a mixture of the labeled compost with a mineral soil (32 g kg(-1)), (iii) measurement of stable isotope ratios, and (iv) isolation and structural comparison by (13)C and (15)N cross-polarization, magic-angle spinning nuclear magnetic resonance (NMR) of different organic fractions, i.e., soluble, colloidal (humic and fulvic type), and particulate (free organic matter and humin), from both the compost and the compost-treated soil. The results showed that the amide forms dominated in all of the newly formed N compounds, but an increased amount of alkali insoluble organic fractions was observed after incubation of the soil. The analysis of the insoluble, particulate fractions shows that nonextractable amides constitute the major pool of newly formed N compounds. The particulate soil fraction isolated by flotation in CHBr(3)-MeOH contained 16.8% of the total soil N and 26% of the (15)N. The (13)C NMR spectra showed that the fulvic acid-like fraction (7.6% of the soil N, 8.8% of (15)N) consisted almost completely of a C=O-containing carbohydrate material, whereas the humic acid-like fraction (20.3% of the total soil N, 8.6% of (15)N) resembled an oxidized lignoproteic fraction containing the most significant aromatic domain. The water soluble fraction was, in both soil and compost, the one with the highest isotopic abundance of (15)N (96%), but the (15)N NMR spectrum revealed minor amounts of soluble mineral N in this fraction and the remainder consisting of amide compounds.

  8. 15N Content Reflects Development of Mycorrhizae and Nitrogen Dynamics During Primary Succession

    Science.gov (United States)

    Hobbie, E. A.; Jumpponen, A.

    2004-05-01

    Mycorrhizal fungi are ubiquitous symbionts on terrestrial plants that are particularly important for plant nitrogen nutrition. 15N content appears to be a useful marker of the mycorrhizal role in plant nitrogen supply because of an apparent fractionation against 15N during transfer of nitrogen from mycorrhizal fungi to host plants. Because plants developing during primary succession are gradually colonized by mycorrhizal fungi, such situations provide good opportunities to study interactions between mycorrhizal colonization and plant 15N content. Here, we present results of a study of nitrogen isotope patterns in ecosystem components during the first 100 years of ecosystem development after glacial retreat, and compare those patterns with those on adjacent mature terrain. Soils in primary succession were depleted in 15N relative to nitrogen-fixing plants. Nonmycorrhizal plants and plants generally colonized by ectomycorrhizal, ericoid, or arbuscular fungi showed similar 15N content very early in succession (-4 to -6‰ ), corresponding to low colonization levels of all plant species. Subsequent colonization of evergreen plants by ectomycorrhizal and ericoid fungi led to a 5-6‰ decline in 15N content, indicating transfer of 15N-depleted N from fungi to plants. The values recorded (-10 to -14‰ ) are among the lowest yet observed in vascular plants. Nonmycorrhizal plants and plants colonized by arbuscular mycorrhizal fungi did not decline in 15N content. Most ectomycorrhizal and saprotrophic fungi were similar in 15N content in early succession (-1 to -3‰ ), with the notable exception of ectomycorrhizal fungi suspected of proteolytic capabilities, which were 15N enriched relative to all other fungi. 15N contents in both plants and soil from the mature site were 5‰ greater than in recently exposed sites. We conclude that 1) the primary nitrogen source to this ecosystem must be atmospheric deposition, 2) low plant 15N content generally corresponds with greater

  9. A Novel Virus-Like Particle Based Vaccine Platform Displaying the Placental Malaria Antigen VAR2CSA.

    Directory of Open Access Journals (Sweden)

    Susan Thrane

    Full Text Available Placental malaria caused by Plasmodium falciparum is a major cause of mortality and severe morbidity. Clinical testing of a soluble protein-based vaccine containing the parasite ligand, VAR2CSA, has been initiated. VAR2CSA binds to the human receptor chondroitin sulphate A (CSA and is responsible for sequestration of Plasmodium falciparum infected erythrocytes in the placenta. It is imperative that a vaccine against malaria in pregnancy, if administered to women before they become pregnant, can induce a strong and long lasting immune response. While most soluble protein-based vaccines have failed during clinical testing, virus-like particle (VLP based vaccines (e.g., the licensed human papillomavirus vaccines have demonstrated high efficacy, suggesting that the spatial assembly of the vaccine antigen is a critical parameter for inducing an optimal long-lasting protective immune response. We have developed a VLP vaccine display platform by identifying regions of the HPV16 L1 coat protein where a biotin acceptor site (AviTagTM can be inserted without compromising VLP-assembly. Subsequent biotinylation of Avi-L1 VLPs allow us to anchor monovalent streptavidin (mSA-fused proteins to the biotin, thereby obtaining a dense and repetitive VLP-display of the vaccine antigen. The mSA-VAR2CSA antigen was delivered on the Avi-L1 VLP platform and tested in C57BL/6 mice in comparison to two soluble protein-based vaccines consisting of naked VAR2CSA and mSA-VAR2CSA. The mSA-VAR2CSA Avi-L1 VLP and soluble mSA-VAR2CSA vaccines induced higher antibody titers than the soluble naked VAR2CSA vaccine after three immunizations. The VAR2CSA Avi-L1 VLP vaccine induced statistically significantly higher endpoint titres compared to the soluble mSA-VAR2CSA vaccine, after 1st and 2nd immunization; however, this difference was not statistically significant after 3rd immunization. Importantly, the VLP-VAR2CSA induced antibodies were functional in inhibiting the binding of

  10. Nitrogen stable isotope composition (δ15N) of vehicle-emitted NOx.

    Science.gov (United States)

    Walters, Wendell W; Goodwin, Stanford R; Michalski, Greg

    2015-02-17

    The nitrogen stable isotope ratio of NOx (δ(15)N-NOx) has been proposed as a regional indicator for NOx source partitioning; however, knowledge of δ(15)N values from various NOx emission sources is limited. This study presents a detailed analysis of δ(15)N-NOx emitted from vehicle exhaust, the largest source of anthropogenic NOx. To accomplish this, NOx was collected from 26 different vehicles, including gasoline and diesel-powered engines, using a modification of a NOx collection method used by the United States Environmental Protection Agency, and δ(15)N-NOx was analyzed. The vehicles sampled in this study emitted δ(15)N-NOx values ranging from -19.1 to 9.8‰ that negatively correlated with the emitted NOx concentrations (8.5 to 286 ppm) and vehicle run time because of kinetic isotope fractionation effects associated with the catalytic reduction of NOx. A model for determining the mass-weighted δ(15)N-NOx from vehicle exhaust was constructed on the basis of average commute times, and the model estimates an average value of -2.5 ± 1.5‰, with slight regional variations. As technology improvements in catalytic converters reduce cold-start emissions in the future, it is likely to increase current δ(15)N-NOx values emitted from vehicles.

  11. Growth, Water Use, and Nitrate-15N Uptake of Greenhouse Tomato as Influenced by Different Irrigation Patterns,15N Labeled Depths, and Transplant Times.

    Science.gov (United States)

    Hou, Maomao; Jin, Qiu; Lu, Xinyu; Li, Jiyu; Zhong, Huizhen; Gao, Yue

    2017-01-01

    Increasing water use efficiency and reducing nitrogen pollutant discharge are important tasks for modern agriculture. To evaluate the effect of alternate partial root-zone irrigation (APRI) on tomato plant growth, water use efficiency and nitrate- 15 N uptake, an experiment was conducted from June to December in 2014 under greenhouse condition in northern China. The experiment contained two irrigation patterns [APRI and conventional irrigation (CI)], two 15 N labeled depths in soil (10 and 50 cm) and two transplant time (early and late summer). Results showed that, compared to CI, APRI did not significantly ( p > 0.05) impact the growth and biomass accumulation in aboveground part of tomato, while it enhanced the root, reflecting by greater length density, and more dry mass. APRI produced marginally lower yields, but saved 34.9% of irrigation water, and gave a 37.6-49.9% higher water use efficiency relative to CI. In addition, APRI improved fruit quality, mainly through increasing the contents of soluble solid (by 12.8-21.6%), and vitamin C (2.8-12.7%), and the sugar/acid ratio (3.5-8.5%). The 15 N utilization efficiency ( 15 NUE) in APRI was higher than that in CI, which was more evident when 15 N was labeled at 50 cm depth. Significant ( p greenhouse could benefit the nitrate-N recovery and increase the water use efficiency in tomato.

  12. Spatial relationship between δ15N and elevation in agricultural landscapes

    Directory of Open Access Journals (Sweden)

    F. L. Walley

    2008-05-01

    Full Text Available Understanding of the nitrogen (N cycle and its spatial variability is important for managing ecosystems. Soil δ15N, as an important indicator of different soil nitrogen cycling processes, may provide critical information about the spatial variability in soil N cycling. The objective of this study was to examine the dominant landscape scale variability of δ15N, the location of the variability and its spatial relationship with elevation. Soil δ15N and elevation were measured along two transects (Davidson and Elstow, Saskatchewan, Canada. Each transect had 128 points with 3 m sampling intervals. Higher δ15N values typically occurred in topographic depressions as compared to knolls. The coefficient of determination revealed a significant linear relationship between δ15N and elevation (r2=0.27 at Davidson whereas no relationship (r2=0.00 was detected for the Elstow transect. However, wavelet spectra, cross wavelet, and squared wavelet coherency analysis revealed spatial relationships between δ15N and elevation at both sites. A strong coherency between δ15N and elevation at large scales (96 m or more was detected for both transects. The Davidson transect showed an out of phase coherency at a topographically elevated area at the beginning and the end of the transect. The Elstow transect had a strong out of phase correlation (negative relationship at the middle of the transect (corresponding to a depressions indicating a location dependent relationship between δ15N and elevation. The relationship between δ15N and elevation reflects the effects of hydrology and soil water content over the landscape on N cycling processes.

  13. Characterization of amino acid metabolism by cultured rat kidney cells: Study with 15N

    International Nuclear Information System (INIS)

    Nissim, I.; States, B.; Yudkoff, M.; Segal, S.

    1987-01-01

    The present study evaluates the metabolism of glutamine and glutamate by normal rat kidney (NRK) cells. The major aim was to evaluate the effect of acute acidosis on the metabolism of amino acid and ammonia formation by cultured NRK cells. Experiments at either pH 7.0 or 7.4 were conducted with phosphate-buffered saline supplemented with either 1 mM [5- 15 N]glutamine, [2- 15 N]glutamine, or [ 15 N]glutamate. Incubation with either glutamine or glutamate as a precursor showed that production of ammonia and glucose was increased significantly at pH 7.0 vs 7.4. In experiments with [5- 15 N]glutamine, the authors found that ∼57 and 43% of ammonia N was derived from 5-N of glutamine at pH 7.4 and 7.0, respectively. Three major metabolic pathways of [2- 15 N]glutamine or [ 15 N]glutamate disposal were identified: (1) transamination reactions involving the pH-independent formation of [ 15 N] aspartate and [ 15 N]alanine; (2) the synthesis of [6- 15 NH 2 ]adenine nucleotide, a process more active at pH 7.4 vs. 7.0; and (3) glutamine synthesis from [ 15 N]glutamate, especially at pH 7.4. The data indicate that NRK cells in culture consume glutamine and glutamate and generate ammonia and various amino acids, depending on the H + concentration in the media. The studies suggest that these cell lines may provide a useful model for studying various aspects of the effect of pH on rat renal ammoniagenesis

  14. Covalent binding of reduced metabolites of [{sup 15}N{sub 3}]TNT to soil organic matter during a bioremediation process analyzed by {sup 15}N NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Achtnich, C.; Fernandes, E.; Bollag, J.M.; Knackmuss, H.J.; Lenke, H.

    1999-12-15

    Evidence is presented for the covalent binding of biologically reduced metabolites of 2,4,6-{sup 15}N{sub 3}-trinitrotoluene (TNT) to different soil fractions, using liquid {sup 15}N NMR spectroscopy. A silylation procedure was used to release soil organic matter from humin and whole soil for spectroscopic measurements. TNT-contaminated soil was spiked with 2,4,6-{sup 15}N{sub 3}-trinitrotoluene and {sup 14}C-ring labeled TNT, before treatment in a soil slurry reactor. During the anaerobic/aerobic incubation the amount of radioactivity detected in the fulvic and humic acid fractions did not change significantly whereas the radioactivity bound to humin increased to 71%. The {sup 15}N NMR spectra of the fulvic acid samples were dominated by a large peak that corresponded to aliphatic amines or ammonia. In the early stages of incubation, {sup 15}N NMR analysis of the humic acids indicated bound azoxy compounds. The signals arising from nitro and azoxy groups disappeared with further anaerobic treatment. At the end of incubation, the NMR shifts showed that nitrogen was covalently bound to humic acid as substituted amines and amides. The NMR spectra of the silylated humin suggest formation of azoxy compounds and imine linkages. Bound metabolites possessing nitro groups were also detected. Primary amines formed during the anaerobic incubation disappeared during the aerobic treatment. Simultaneously, the amount of amides and tertiary amines increased. Nitro and azoxy groups of bound molecules were still present in humin at the end of the incubation period. Formation of azoxy compounds from partially reduced TNT followed by binding and further reduction appears to be an important mechanism for the immobilization of metabolites of TNT to soil.

  15. Urinary excretion of 15N during intraportal infusion of 15N-ammonia in chickens fed low or high protein diet

    International Nuclear Information System (INIS)

    Karasawa, Yutaka; Koh, Katsuki; Takahashi, Akira; Sumiya, Ryuta

    1985-01-01

    The purpose of this study is to examine time courses of 15 N in urinary ammonia and total N when 15 N-labeled ammonium acetate was continuously infused for 1 hour into chickens fed a 5 or 20 % protein diet. 15 N-enrichment of urinary nitrogen in the two dietary groups increased sharply in ammonia for the first 20 minutes and to a less extent linearly in total N for the first 30 minutes, and then gradually in both ammonia and total N. Through the ammonia infusion, the 15 N-enrichment of urinary ammonia was higher in the chickens fed the low protein diet than in those fed the high protein diet; both of them were higher than 15 N-enrichments of urinary N, which were almost the same in the two dietary groups. The urinary total N from the infused ammonia rose linearly for the first 40 minutes but thereafter did not rise further in the two dietary groups, whereas the endogenous urinary total N tended to decrease a little in the chichens fed the high protein diet but unchanged in those fed the low protein diet. The urinary ammonia from the infused ammonia increased sharply for the first 20 minutes, then linearly but at a lower rate in the chickens fed the high protein diet, whereas that in the chickens fed the low protein diet rose linearly throughout ammonia infusion. In contrast, the endogenous urinary ammonia showed no change in the chickens fed the high protein diet while it showed a tendency to increase a little in these fed the low protein diet. These results indicate that the increased urinary ammonia and total N during ammonia infusion are derived mostly from the infused ammonia in chickens fed 5 and 20% protein diets. (author)

  16. Comparison of unenriched versus 15N-enriched fertilizer as a tracer for N fertilizer uptake

    International Nuclear Information System (INIS)

    Meints, V.W.; Shearer, G.; Kohl, D.H.; Kurtz, L.T.

    1975-01-01

    A greenhouse experiment was conducted on three soils with differing cropping and fertilization histories to determine whether unenriched fertilizer N can be used in the same manner as 15 N-enriched fertilizer to estimate the amount of plant N derived from fertilizer. Estimates using unenriched fertilizer N were compared with estimates using two 15 N enrichment levels. Use of unenriched fertilizer N led to underestimation of the amount of fertilizer N in the plant material in four of six cases when compared to 15 N-enriched fertilizer. Standard deviations of the estimates of fertilizer-derived N in plant material were considerably greater when unenriched fertilizer was used. (U.S.)

  17. Levels of 16O near 13 MeV excitation from 15N+p reactions

    International Nuclear Information System (INIS)

    Bray, K.H.; Frawley, A.D.; Ophel, T.R.; Barker, F.C.

    1977-02-01

    Angular distributions, a O 0 excitation function and Doppler-broadened γ-ray profiles for the reaction 15 N(p,α 1 γ), and angular distributions for the 15 N(p,αsub(o)) reaction, have been measured for proton energies from about 900 to 1250 keV. These data, together with analysing powers from the 15 N(p,αsub(o)) reaction with polarized protons, have been satisfactorily fitted by means of R-matrix theory, in terms of the known levels of 16 O in the 13 MeV region together with background contributions. (Author)

  18. Evaluation for dinitrogen fixation of alfalfa in field based on δ15N value

    International Nuclear Information System (INIS)

    Yao Yunyin; Chen Ming; Zhang Xizhong

    1992-12-01

    The dinitrogen fixation rate of alfalfa was estimated grown in pot and field experiments. β values (isotope fraction factor) of 7 cultivars of alfalfa (Medicago sativa L.) and white clover (Trifolium repens L.) grown in N-free liquid culture medium were examined. Variations in the δ 15 N values of varieties of alfalfa at growing seasons and forage grasses grown under various conditions were measured. %Ndfa of alfalfa was estimated using the natural 15 N abundance method, 15 N isotope dilution method and total N difference, and their accuracy was compared

  19. Influence of intermittent preventive treatment on antibodies to VAR2CSA in pregnant Cameroonian women

    DEFF Research Database (Denmark)

    Babakhanyan, Anna; Tutterrow, Yeung L; Bobbili, Naveen

    2016-01-01

    Intermittent preventive treatment (IPT) and insecticide-treated bed nets are the standard of care for preventing malaria in pregnant women. Since these preventive measures reduce exposure to malaria, their influence on the antibody (Ab) response to the parasite antigen VAR2CSA was evaluated...... in pregnant Cameroonian women exposed to holoendemic malaria. Ab levels to full-length VAR2CSA (FV2), variants of the six Duffy binding like (DBL) domains, and proportion of high avidity Ab to FV2 were measured longitudinally in 92 women before and 147 women after IPT. As predicted, reduced exposure...... interfered with acquisition of Ab in primigravidae, with 71% primigravidae being seronegative to FV2 at delivery. Use of IPT for > 13 weeks by multigravidae resulted in 26% of women being seronegative at delivery and a significant reduction in Ab levels to FV2, DBL5, DBL6, proportion of high avidity Ab to FV...

  20. Structure of the DBL3x domain of pregnancy-associated malaria protein VAR2CSA complexed with chondroitin sulfate A

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K.; Gittis, A.G.; Nguyen, P.; Gowda, D.C.; Miller, L.H.; Garboczi, D.N. (NIH); (Penn)

    2008-09-19

    Plasmodium falciparum-infected erythrocytes bind to chondroitin sulfate A (CSA) in the placenta via the VAR2CSA protein, a member of the P. falciparum erythrocyte membrane protein-1 family, leading to life-threatening malaria in pregnant women with severe effects on their fetuses and newborns. Here we describe the structure of the CSA binding DBL3x domain, a Duffy binding-like (DBL) domain of VAR2CSA. By forming a complex of DBL3x with CSA oligosaccharides and determining its structure, we have identified the CSA binding site to be a cluster of conserved positively charged residues on subdomain 2 and subdomain 3. Mutation or chemical modification of lysine residues at the site markedly diminished CSA binding to DBL3x. The location of the CSA binding site is an important step forward in the molecular understanding of pregnancy-associated malaria and offers a new target for vaccine development.

  1. [Chronobiological studies on effect of cyclosporin A (CsA) against adult male worms of Schistosoma mansoni in vitro].

    Science.gov (United States)

    Liu, J; Chappell, L H

    1998-01-01

    To study the action mode of cyclosporin A (CsA) against Schistosoma mansoni in vitro. MF1 mice were infected with Schistosoma mansoni cercariae for 6 weeks when the adult worms were recovered by portal perfusion. The male worms of S. mansoni recovered were exposed to varying concentrations of CsA at 8, 16, and 24 h in vitro. Drug induced damage to the male worm surface was chrono-biologically observed throughout these experiments by SEM. After the male worms of S. mansoni were incubated with 1 microgram/ml CsA for 8-24 h, the tegument showed swelling of ridges with appearance of holes on their surface and detachment of a part of spines. The above damage of the tegument became more evident in male worms after incubation with 10, 15, 20 micrograms/ml CsA for 8-24 h. Moreover, incubation of male worms with 25 micrograms/ml CsA for 8-24 h resulted in significant deformation and disruption of tegument, rupture of ridges and detachment of spines. The tegumental damage of male worms of S. mansoni was dose- and time-dependent. The antischistosomal action of CsA is direct, the schistosome tegument appears to be the main site for CsA attack.

  2. Backbone dynamics of the EIAV-Tat protein from 15N relaxation studies

    International Nuclear Information System (INIS)

    Ejchart, A.; Herrmann, F.; Roesch, P.; Sticht, H.; Willbold, D.

    1994-01-01

    The work investigates the mobility of EIAV-Tat protein backbone by measuring the relaxation parameters of the 15 N nitrogens. High degree of the flexibility, non-typical of rigid, well structured proteins was shown

  3. Positive selection of Plasmodium falciparum parasites with multiple var2csa-type PfEMP1 genes during the course of infection in pregnant women

    DEFF Research Database (Denmark)

    Sander, Adam F; Salanti, Ali; Lavstsen, Thomas

    2011-01-01

    multiple genes coding for different VAR2CSA proteins, and parasites with >1 var2csa gene appear to be more common in pregnant women with placental malaria than in nonpregnant individuals. We present evidence that, in pregnant women, parasites containing multiple var2csa-type genes possess a selective...

  4. Nitrogen source tracking with δ15N content of coastal wetland plants in Hawaii

    Science.gov (United States)

    Gregory L. Bruland; Richard A.. Mackenzie

    2010-01-01

    Inter- and intra-site comparisons of the nitrogen (N) stable isotope composition of wetland plant species have been used to identify sources of N in coastal areas. In this study, we compared δ15N values from different herbaceous wetland plants across 34 different coastal wetlands from the five main Hawaiian Islands and investigated relationships of δ15N with...

  5. Methodical investigation of the endogenous N excretion in feces by 15N-labelled rats

    International Nuclear Information System (INIS)

    Bergner, U.; Bergner, H.

    1983-01-01

    Wistar rats (approximately 100g live weight, n = 8) received a wheat diet and were labelled over a period of 7 days with 15 N-ammonium acetate. From day 1 - 5 of the experiment after the end of the labelling feces and urine were collected and analysed. After the animals were killed (day 5 of the experiment) the atom-% 15 N excess ( 15 N') in the contents of the digestive tract as well as in the tissues of stomach wall, intestinal wall, liver, pancreas and blood plasma was determined. The TCA-soluble fraction of the blood plasma showed 0.44 atom-% 15 N' on day 5 after the end of 15 N labelling. 3 hours before the killing fecal N also showed 0.44 and during the last collection period (24 hours before) an average of 0.51 atom-% 15 N'. Urine decreased in the same period from 0.71 to 0.59 atom-% 15 N'. The endogenous fecal N is calculated to 88%. As the tissues of the digestive tract are likely to supply the biggest part of the endogenous fecal protein, the values of atom-% 15 N' from the TCA-precipitable fraction of the intestinal wall and of the pancreas gland was calculed to an average of 0.526. According to this the calculation endogenous fecal N is 84%. It is probable that the quota of endogenous fecal N in the total amount of fecal N varies in dependence on the fermentable crude fiber in the diet as well as on the age of the test animals and thus the bacterial protein synthesis in the colon. As the N used by the bacteria is likely to come from the TCA-soluble fraction of the blood, the calculation formula suggested, which uses the TCA-soluble fraction of the blood plasma, achieves good approximate values also for higher bacterial protein synthesis in the colon. (author)

  6. Fertilizer-n uptake and distribution in rice plants using 15N tracer technique

    International Nuclear Information System (INIS)

    Yan Juan; Shen Qirong; Yin Bin; Wan Xinjun

    2009-01-01

    Fertilizer-nitrogen (N) uptake and distribution in rice were studied using 15 N tracer technique. The results obtained were as follows. At the tillering, jointing and booting, and anthesis stages, 23.1%, 8.3% and 19.9% of N were taken from fertilizer applied in base (N1), tillering (N2) and jointing and booting (N3), respectively. The 15 N translocation from anthesis to maturity was in the order of N3>N1>N2, but the 15 N translocation efficiency was higher in N1 (base fertilizer treatment) than in the other two treatments. At maturity, the 15 N distribution in straw in the treatments of N1, N2 and N3 was only 24.3%, 26.7% and 30.4%, respectively. No matter what time the N fertilizer was applied, the 15 N uptake was mostly distributed in leaves, then in the sheath, the least in stem, and 15 N distribution in spike increased with the increased 15 N translocation from nutritional organs to spike after anthesis. The study also showed that the 15 N uptake at maturity in N1, N2 and N3 treatments was 10.3%, 5.9% and 12.4%, respectively. The results indicated that (1) when soil N content was not high, the base fertilizer application was important to rice growth, and optimal increment might help increase tillering, and improve rice quality; (2) the initiation fertilizer significantly promoted quantities during grain filling, and thus application of N fertilizer in initiation was of considerable advance in increasing N harvest index (NHI); (3) the rice plants absorbed less N applied in tillering stage due to a big N loss in that period. Therefore a little bit increase of base N fertilizer with no or very small amount of tillering fertilizer, together with some topdressing of N fertilizer during initiation could improve N uptake by rice. (authors)

  7. 15N abundance in Antarctica: origin of soil nitrogen and ecological implications

    International Nuclear Information System (INIS)

    Wada, E.; Shibata, R.; Torii, T

    1981-01-01

    The results of an investigation of the nitrogen cycle in Antartica are reported which show that nitrate in Antarctic soils is extremely depleted in 15 N compared with biogenic nitrogen and that algae collected from a nitrate-rich saline pond and from a penguin rookery exhibit, respectively, the lowest and the highest 15 N/ 14 N ratios among terrestrial biogenic nitrogen so far observed. The possible causes of these extreme nitrogen isotopic compositions are discussed. (U.K.)

  8. Compaction stimulates denitrification in an urban park soil using 15N tracing technique

    DEFF Research Database (Denmark)

    Li, Shun; Deng, Huan; Rensing, Christopher Günther T

    2014-01-01

    Soils in urban areas are subjected to compaction with accelerating urbanization. The effects of anthropogenic compaction on urban soil denitrification are largely unknown. We conducted a study on an urban park soil to investigate how compaction impacts denitrification. By using 15N labeling method......, no statistical difference in total N losses and 15N-(N2O+N2) flux between the uncompacted soil and the compacted soil was detected. Compaction promoted soil denitrification and may impact urban N biogeochemical cycling....

  9. Determination of protein turnover parameters in athletes using 15N tracers

    International Nuclear Information System (INIS)

    Krumbiegel, P.; Kuehne, K.; Faust, H.; Bornhak, H.; Junghans, P.; Zerbes, H.

    1985-01-01

    In 2 adolescent female athletes engaged in technical-acrobatic sports the influence of a high protein diet on the protein turnover rate under training conditions was investigated by means of 15 N-glycine. Protein synthesis was significantly increased, whereas the utilization of nutritive nitrogen was decreased as expected. The 15 N tracer technique is well suited to determine the protein requirements under special training conditions

  10. North Atlantic ecosystem shifts revealed by cod otolith δ15N and δ13C chronologies

    DEFF Research Database (Denmark)

    Pedersen, Jens Brøgger; Nielsen, Jens Munk; Steingrund, Petur

    . To study the link between environmental changes and ecosystem trophic structure we developed δ15N and δ13C chronologies by analyzing the organic matrix of cod otoliths from the Faroe Shelf cod population (1950-2010) and the Nuuk Fjord cod population (1927-2009). Significant correlations between δ15N & δ13C...... of organic matrix of otolith core material (Nuuk Fjord) and annual growth increments in Ocean Quahog (A. Islandica) shells will be included....

  11. Ecosystem N distribution and δ15N during a century of forest regrowth after agricultural abandonment

    Science.gov (United States)

    Compton, J.E.; Hooker, T.D.; Perakis, S.S.

    2007-01-01

    Stable isotope ratios of terrestrial ecosystem nitrogen (N) pools reflect internal processes and input–output balances. Disturbance generally increases N cycling and loss, yet few studies have examined ecosystem δ15N over a disturbance-recovery sequence. We used a chronosequence approach to examine N distribution and δ15N during forest regrowth after agricultural abandonment. Site ages ranged from 10 to 115 years, with similar soils, climate, land-use history, and overstory vegetation (white pine Pinus strobus). Foliar N and δ15N decreased as stands aged, consistent with a progressive tightening of the N cycle during forest regrowth on agricultural lands. Over time, foliar δ15N became more negative, indicating increased fractionation along the mineralization–mycorrhizal–plant uptake pathway. Total ecosystem N was constant across the chronosequence, but substantial internal N redistribution occurred from the mineral soil to plants and litter over 115 years (>25% of ecosystem N or 1,610 kg ha−1). Temporal trends in soil δ15N generally reflected a redistribution of depleted N from the mineral soil to the developing O horizon. Although plants and soil δ15N are coupled over millennial time scales of ecosystem development, our observed divergence between plants and soil suggests that they can be uncoupled during the disturbance-regrowth sequence. The approximate 2‰ decrease in ecosystem δ15N over the century scale suggests significant incorporation of atmospheric N, which was not detected by traditional ecosystem N accounting. Consideration of temporal trends and disturbance legacies can improve our understanding of the influence of broader factors such as climate or N deposition on ecosystem N balances and δ15N.

  12. Metabolism of [15N]alanine in the ectomycorrhizal fungus Paxillus involutus

    International Nuclear Information System (INIS)

    Chalot, M.; Finlay, R.D.; Ek, H.; Söderström, B.

    1995-01-01

    Chalot, M., Finlay, R. D., Ek, H., and Söderström, B. 1995. Metabolism of [ 15 N]alanine in the ectomycorrhizal fungus Paxillus involutus. Experimental Mycology 19, 297-304. Alanine metabolism in the ectomycorrhizal fungus Paxillus involutus was investigated using [ 15 N]alanine. Short-term exposure of mycelial discs to [ 15 N]alanine showed that the greatest flow of 15 N was to glutamate and to aspartate. Levels of enrichment were as high as 15-20% for glutamate and 13-18% for aspartate, whereas that of alanine reached 30%. Label was also detected in the amino-N of glutamine and in serine and glycine, although at lower levels. Preincubation of mycelia with aminooxyacetate, an inhibitor of transamination reactions. resulted in complete inhibition of the flow of the label to glutamate, aspartate, and amino-N of glutamine, whereas [ 15 N]alanine rapidly accumulated. This evidence indicates the direct involvement of alanine aminotransferase for translocation of 15 N from alanine to glutamate. Alanine may be a convenient reservoir of both nitrogen and carbon. (author)

  13. Application of C30B15N15 heterofullerene in the isoniazid drug delivery: DFT studies

    Science.gov (United States)

    Hazrati, Mehrnoosh Khodam; Bagheri, Zargham; Bodaghi, Ali

    2017-05-01

    Using density functional theory, we have investigated the potential application of a C30B15N15 heterofullerene in anti-cancer isoniazid drug delivery. It was found that isoniazid prefers to attach via its -NH2 group to a boron atom of the C30B15N15 with releasing a large energy of about 21.91 kcal/mol. Our partial density of states analysis demonstrates that the boron atoms significantly contribute in generation of virtual orbitals of C30B15N15 fullerene, indicating that these atoms will be suitable for nucleophilic attack rather than carbon atoms. In addition to the large released energy, the electronic properties C30B15N15 are significantly sensitive to the isoniazid attachment which can recognize the drug trajectory by affecting the fluorescence emission properties. Unlike, different nanostructures whose structures need to be manipulated to be suitable for drug delivery, the C30B15N15 fullerene can be used in the pristine form. We proposed a drug release mechanism in cancer tissues, representing that in the low pH of the cancer cells the drug and C30B15N15 fullerene are considerably protonated, thereby separating the drug from the surface of the fullerene. The reaction mechanism of the drug with the fullerene is changed from covalence in natural environment to hydrogen bonding in acidic cancer cells.

  14. Quantifying below-ground nitrogen of legumes: Optimizing procedures for 15N shoot-labelling

    International Nuclear Information System (INIS)

    Khan, D.F.; Peoples, M.B.; Herridge, D.F.

    2003-01-01

    Quantifying below-ground nitrogen (N) of legumes is fundamental to understanding their effects on soil mineral N fertility and on the N economies of following or companion crops in legume-based rotations. Methodologies based on 15 N-labelling of whole plants with subsequent measurement of 15 N in recovered plant parts and in the root-zone soil have proved promising. We report four glasshouse experiments with objectives to develop appropriate protocols for in situ 15 N labelling of four pulses, faba bean (Vicia faba), chickpea (Cicer arietinum), mung bean (Vigna radiata) and pigeon pea (Cajanus cajan). Treatments included 15 N-urea concentration, feeding technique, leaflet/petiole position, and frequency of feeding. Nitrogen- 15 -labelling via the leaf-flap was best for faba bean, mung and pigeon pea, whilst petiole feeding was best for chickpea, in all cases using 0.2-mL volumes of 0.5% urea (98 atom% 15 N excess). The implications of uneven enrichment of the nodulated roots because of effects of the 15 N-depleted nodules when calculating root-derived N in soil are discussed. (author)

  15. Evaluation of natural 15N abundance method in estimating symbiotic dinitrogen fixation by leguminous grasses

    International Nuclear Information System (INIS)

    Yao Yunyin; Cheng Ming; Ma Changlin; Wang Zhidong; Hou Jinqin; Zhang Lihong; Luo Yongyun

    1991-01-01

    Natural 15 N abundance method was used to estimate contribution of symbiotic dinitrogen fixation by leguminous grasses. With the method the expensive 15 N fertilizer did not need to be applied to the soil and the normal ecosystem was not disturbed. Collecting samples of shoots of leguminous grasses and measuring the content of 15 N in them wee all to do for estimating potential of symbiotically fixed N 2 . Isotopic fractionation associated with N 2 fixation by legumes was studied. Values for 7 cultivars of alfalfa were ranged between 1.0000 ∼ 1.0015 (δ 15 N values were -0.05 ∼ 1.47 per mille); and the values for white clover, mung bean and whitepopinac lead tree were 0.0079, 0.9983 and 1.0018 (δ 15 N values: 2.15, 1.74 and -1.81 per mille) respectively. According to the δ 15 N values of grasses tested, the potential of N 2 fixation for 6 cultivars of alfalfa was estimated. Glory and rambler had higher potential of N 2 fixation; Baoding, Aigonquin and Minto had lower potential, and Peru was the lowest.N 2 fixing activity of alfalfa varied with different periods. The peak was found between June and July. Effects of non-N 2 -fixing references and different methods on estimates of %Ndfa of leguminous grasses were also discussed

  16. Highly 15N-Enriched Chondritic Clasts in the Isheyevo Meteorite

    Energy Technology Data Exchange (ETDEWEB)

    Bonal, L; Huss, G R; Krot, A N; Nagashima, K; Ishii, H A; Bradley, J P; Hutcheon, I D

    2009-01-14

    The metal-rich carbonaceous chondrites (CB and CH) have the highest whole-rock {sup 15}N enrichment ({delta}{sup 15}N up to +1500{per_thousand}), similar to {delta}{sup 15}N values reported in micron-sized regions (hotspots) of Interplanetary Dust Particles (IDPs) of possibly cometary origin and fine-grained matrices of unmetamorphosed chondrites. These {sup 15}N-rich hotspots are commonly attributed to low-temperature ion-molecule reactions in the protosolar molecular cloud or in the outer part of the protoplanetary disk. The nature of the whole-rock {sup 15}N enrichment of the metal-rich chondrites is not understood. We report a discovery of a unique type of primitive chondritic clasts in the CH/CB-like meteorite Isheyevo, which provides important constraints on the origin of {sup 15}N anomaly in metal-rich chondrites and nitrogen-isotope fractionation in the Solar System. These clasts contain tiny chondrules and refractory inclusions (5-15 {micro}m in size), and abundant ferromagnesian chondrule fragments (1-50 {micro}m in size) embedded in the partly hydrated, fine-grained matrix material composed of olivines, pyroxenes, poorly-organized aromatic organics, phyllosilicates and other hydrous phases. The mineralogy and oxygen isotope compositions of chondrules and refractory inclusions in the clasts are similar to those in the Isheyevo host, suggesting formation at similar heliocentric distances. In contrast to the previously known extraterrestrial samples, the fine-grained material in the clasts is highly and rather uniformly enriched in {sup 15}N, with bulk {delta}{sup 15}N values ranging between +1000 and +1300{per_thousand}; the {delta}{sup 15}N values in rare hotspots range from +1400 to +4000{per_thousand}. Since fine-grained matrices in the lithic clasts are the only component containing thermally unprocessed (during CAI and chondrule formation or during impact melting) materials that accreted into the metal rich chondrite parent body(ies), the {sup 15}N

  17. Metabolic rates of 15N-D- and 15N-L-phenylalanine in an amino acid mixture for parenteral feeding

    International Nuclear Information System (INIS)

    Wutzke, K.; Heine, W.; Drescher, U.

    1982-01-01

    15 N investigations on the metabolism of L- and D-phenylalanine under conditions of parenteral feeding with the aminoacid solution Infesol in 6 infants revealed a retention rate of 83.4 +- 3.4 per cent for the L-form and of 36.6 +- 5.2 per cent for the D-form. When the D-isomer was raised from 1:3 to 1:1 in relation to the L-Form, 32.6 per cent of the infused D-phenylalanine were still retained. After continuous 24-hour infusion of the tracers, the maximum of 15 N excretion in the urine was reached between the 24th and the 30th hour. But little incorporation of 15 N-nitrogen was found in the serum and erythrocytes because of the relatively long half-life period of these proteins. Changes in the composition of commercial DL-amino acid mixtures will only be possible after determining the utilization rates of all essential and non-essential D-amino acids being used in such mixtures. (author)

  18. Absorption of ammonium sulphate {sup 15}N by coffee plants; Recuperacao do {sup 15}N do sulfato de amonio por plantas de cafe

    Energy Technology Data Exchange (ETDEWEB)

    Fenilli, Tatiele Anete Bergamo; Reichardt, Klaus; Bacchi, Osny Oliveira Santos [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Fisica do Solo]. E-mail: tatiele@cena.usp.br; Trivelin, Paulo Cesar Ocheuze [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis; Dourado Neto, Durval [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz. Dept. de Producao Vegetal

    2005-07-01

    The objective of this study was to quantify the absorption of ammonium sulphate {sup 15}N by coffee plants. Treatments consisted of five sub-plots of 9 plants, of which the three central ones received 280 kg ha{sup -1} of {sup 15}N, applied at four times: 1/4 on 01 Set 03; 1/4 on 03 Nov 03; 1/4 on 15 Dec 03 and 1/4 on 30 Jan 04. The isotopic enrichment was 2,072 {+-} 0,001 atom % {sup 15}N. The dry matter of the shoot was evaluated every 60 days, using one plant per replicate, collected outside the sub-plot. They were as similar as possible to the labeled plants, which were used only for isotopic and Total N analysis, after being dried at 65 deg C until constant weight. At harvest, plants had absorbed 42,88% of the fertilizer N. Leaves accumulated the largest amount of fertilizer N, and were also the compartments that received most N from other parts of the plant. The following partition of the fertilizer N was found at harvest: 23.01% in young leaves, 6.23% in old leaves, 4,46% in stem, 3.46% in fruits, 3.10% in young branches and 2.63% in old branches. (author)

  19. Epitope mapping and topographic analysis of VAR2CSA DBL3X involved in P-falciparum placental sequestration

    DEFF Research Database (Denmark)

    Dahlback, Madeleine; Rask, Thomas Salhøj; Andersen, Pernille

    2006-01-01

    and a parasite-encoded protein on the surface of infected erythrocytes, believed to be VAR2CSA. VAR2CSA is a polymorphic protein of approximately 3,000 amino acids forming six Duffy-binding-like (DBL) domains. For vaccine development it is important to define the antigenic targets for protective antibodies...... and to characterize the consequences of sequence variation. In this study, we used a combination of in silico tools, peptide arrays, and structural modeling to show that sequence variation mainly occurs in regions under strong diversifying selection, predicted to form flexible loops. These regions are the main...... targets of naturally acquired immunoglobulin gamma and accessible for antibodies reacting with native VAR2CSA on infected erythrocytes. Interestingly, surface reactive anti-VAR2CSA antibodies also target a conserved DBL3X region predicted to form an alpha-helix. Finally, we could identify DBL3X sequence...

  20. Barley Benefits from Organic Nitrogen in Plant Residues Applied to Soil using 15N Isotope Dilution

    International Nuclear Information System (INIS)

    Gadalla, A.M.; Galal, Y.G.M.; Abdel Aziz, H.A.; El-Degwy, S.M.A.; Abd El-Haleem, M.

    2008-01-01

    The experiment was carried out in pots (sandy soil cultivated with Barley plant) under greenhouse conditions, at Inshas, Egypt. The aim was to evaluate the transformation of nitrogen applied either as mineral form ( 15 NH 4 ) 2 SO 4 , or as organic-material-N (plant residues) .Basal recommended doses of P and K were applied. Labeled 15 N as( 15 NH 4 ) 2 SO 4 (5 % a.e) or plant residues (ground leuceana forage, compost, and mixture of them) were applied at a rate of 20 kg N/ ha). 15 N technique was used to evaluate N-uptake and fertilizer use efficiency. The treatments were arranged in a completely randomized block design under greenhouse conditions. The obtained results showed that the dry weight of barley shoots was positively affected by reinforcement of mineral- N with organic-N. On the other hand, the highest dry weight was estimated with leuceana either applied alone or reinforced with mineral N. Similar trend was noticed with N uptake but only with organic N, while with treatment received 50% organic-N. plus 50% mineral- N. the best value of N uptake was recorded with mixture of leuceana and compost. The amount of Ndff was lowest where fertilizer 15 N was applied alone. Comparing Ndff for the three organic treatments which received a combination of fertilizer- 15 N+organic-material-N, results showed that the highest Ndff was occurred with mixture of leuceana and compost, whereas the lowest was induced with individual leuceana treatment. 15 N recovery in shoots of barley ranged between 22.14 % to 82.16 %. The lowest occurred with application of mineral 15 N alone and; the highest occurred where mineral 15 N was mixed with compost or leucaena-compost mixture

  1. Split-root labelling to investigate15N rhizodeposition by Pinus sylvestris and Picea abies.

    Science.gov (United States)

    Veerman, Liz; Kalbitz, Karsten; Schoorl, Jorien C; Tietema, Albert

    2018-03-01

    We investigated the transfer of 15 N into the soil via 15 N uptake and release by tree roots, which involves the principles of the split-root technique. One half of the root system received an injection of ( 15 NH 4 ) 2 SO 4 and the other half equivalent amounts of (NH 4 ) 2 SO 4 at 15 N natural abundance level. 15 N was transferred from one side of the root system ( 15 N side) to the other side ( 14 N side) and released into the soil. The method was conducted with Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst). Two concentration levels of (NH 4 ) 2 SO 4 were used, corresponding with annual N deposition in the Netherlands (30 kg N ha -1 ) and a twelfth of that (2.5 kg N ha -1 ). Samples were taken 3 and 6 weeks after labelling and divided into needles + stem, roots, rhizosphere and bulk soil. Already 3 weeks after labelling, Scots pine took up 23.7 % of the low and 9.1 % of the high amounts of 15 N, while Norway spruce took up 21.5 and 32.1 %, respectively. Both species transported proportions of 15 N to the rhizosphere (0.1-0.2 %) and bulk soil (0.3-0.9 %). The method is a useful tool to investigate the fate of root-derived N in soils, for example, for the formation of stable forms of soil organic matter.

  2. Why is Mineral-Associated Organic Matter Enriched in 15N? Evidence from Grazed Pasture Soil

    Science.gov (United States)

    Baisden, W. T.; Wells, N. S.; Mudge, P. L.; Clough, T. J.; Schipper, L. A.; Ghani, A.; Stevenson, B.

    2014-12-01

    Throughout the scientific literature, measurements across soil depth and density fractions suggest that, with few exceptions, mineral-associated organic matter (OM) has higher δ15N than non-mineral-associated OM. This implies that the δ15N difference between N inputs and mineral-stabilized OM may characterize the microbial processes involved in stabilization and mineral association. Yet current understanding of observed N isotope fractionation in terrestrial ecosystems suggests the large isotope effects are expressed during inorganic N transformations from NH4 to gaseous loss pathways of NH3 volatilization and denitrification. How can the relative importance of N isotope fractionation during OM stabilization versus loss pathways be resolved? We recently examined N isofluxes when a temporary nitrogen excess is created by urine deposition in a New Zealand dairy pasture. We found that the N isotopic composition of volatilized NH3, and NO3 available for leaching or denitrification could not be linked back to the added N using Rayleigh distillation models. Instead, the results imply that the added N was immobilized, and the N available for losses was increasingly derived from mineralization of organic matter during the course of the experiment. These results are consistent with recent evidence of enhanced OM mineralization in urine patches, understanding of N isotope mass balances and long-standing evidence that gross mineralization and immobilization fluxes greatly exceed net mineralization and nitrification, except at very high N saturation. These results suggest that where 15N enrichment occurs due to fractionating loss pathways, the isotope effects are primarily transmitted to immobilized N, forming 15N enriched stabilized OM. This further explains earlier findings that the δ15N of soil OM represents an integrated indicator of losses, reflecting the intensity and duration of pastoral agriculture. We suggest that development of an indicator based on δ15N in

  3. Potential Synergy Activity of the Novel Ceragenin, CSA-13, against Carbapenem-Resistant Acinetobacter baumannii Strains Isolated from Bacteremia Patients

    Directory of Open Access Journals (Sweden)

    Cagla Bozkurt-Guzel

    2014-01-01

    Full Text Available Carbapenem-resistant Acinetobacter baumannii is an important cause of nosocomial infections, particularly in patients in the intensive care units. As chronic infections are difficult to treat, attempts have been made to discover new antimicrobials. Ceragenins, designed to mimic the activities of antimicrobial peptides, are a new class of antimicrobial agents. In this study, the in vitro activities of CSA-13 either alone or in combination with colistin (sulphate, tobramycin, and ciprofloxacin were investigated using 60 carbapenem-resistant A. baumannii strains isolated from bacteremia patients blood specimens. MICs and MBCs were determined by microbroth dilution technique. Combinations were assessed by using checkerboard technique. The MIC50 values (mg/L of CSA-13, colistin, tobramycin, and ciprofloxacin were 2, 1, 1.25, and 80, respectively. The MIC90 (mg/L of CSA-13 and colistin were 8 and 4. The MBCs were equal to or twice greater than those of the MICs. Synergistic interactions were mostly seen with CSA-13-colistin (55%, whereas the least synergistic interactions were observed in the CSA-13-tobramycin (35% combination. No antagonism was observed. CSA-13 appears to be a good candidate for further investigations in the treatment of A. baumannii infections. However, future studies should be performed to correlate the safety, efficacy, and pharmacokinetic parameters of this molecule.

  4. Utilization of 15N in the sequence of mineral fertilizer - forage - animal - slurry - forage

    International Nuclear Information System (INIS)

    Peschke, H.

    1981-01-01

    After systematic application of 15 N-ammonium nitrate, the change of the dinuclidic composition and 15 N quantity was studied by isotope analysis of several open systems in the sequence mineral fertilizer - (soil) - forage - (animal) - slurry - (soil) - forage. The relative 15 N isotope frequency of 50 atom% in the mineral fertilizer declined to 12.2 to 21.4 atom% in the forage (beet, oats, hay) and went down to 3.15 atom% in the slurry of a dairy cow fed on this forage. Silage maize manured with the slurry of the dairy cow only showed 1.98 atom %, green oats grown after the silage maize on the same area was found to have 0.45 atom%. The 15 N quantity of 104.5 g N in the fertilizer gradually decreased to 41.6 g N in the forage, 30.5 g N in the slurry and 22.6 g N in the silage maize. The causes discussed are 15 N isotope dilution as qualitative factor and productive and unproductive N losses as quantitative factors. (author)

  5. Incorporation of 15N-inorganic nitrogen into free-amino acids in germinating corn

    International Nuclear Information System (INIS)

    Samukawa, Kisaburo; Yamaguchi, Masuro

    1979-01-01

    Incorporation of 15 N-labeled compounds, (K 15 NO 3 ) and ( 15 NH 4 ) 2 SO 4 , into free-amino acids was measured in germinating corn. Sterilized seeds of sweet corn (Choko No. 865) were sown on the filter papers soaked in 10 ml of the solution containing one of the labeled compounds (40 ppm N, 99 atom % excess) in petri dishes and germinated at 30 deg C. After 48 hours and 72 hours, 15 N-incorporation was measured in 5 seedlings selected owing to uniform growth. A GC-MS was used for measuring the ratio of 15 N isotopes present in free-amino acids. 15 N incorporation into free-amino acids hardly occurred when corn was germinated in the solution containing K 15 NO 3 , which suggested that endogenous nitrogen was used during the early germination stage of corn when nitrate is present. Incorporation into amino acids was greater when corn was germinated in the medium containing ( 15 NH 4 ) 2 SO 4 , than the case of the solution containing K 15 NO 3 . When corn was germinated in the solution containing ( 15 NH 4 ) 2 SO 4 , assimilation of 15 N into asparagine or aspartic acid was comparatively higher than that into the other amino acids, though the incorporation rate was low. Thus, in intact germinating corn, the hydrolyzed product of protein was utilized for germination with priority, and dependence on exogenous nitrogen was low. (Kaihara, S.)

  6. Estimate of symbiotically fixed nitrogen in field grown soybeans using variations in 15N natural abundance

    International Nuclear Information System (INIS)

    Amarger, N.; Durr, J.C.; Bourguignon, C.; Lagacherie, B.; Mariotti, A.; Mariotti, F.

    1979-01-01

    The use of variations in natural abundance of 15 N between nitrogen fixing and non nitrogen fixing soybeans was investigated for quantitative estimate of symbiotic nitrogen fixation. Isotopic analysis of 4 varieties of inoculated and non-inoculated soybeans growing under field conditions, with and without N-fertilizer was determined. It was found that inoculated soybeans had a significantly lower 15 N content than non-inoculated ones. Estimates of the participation of fixed N to the total nitrogen content of inoculated soybeans were calculated from these differences. They were compared to estimates calculated from differences in N yield between inoculated and non-inoculated plants and to the nitrogenase activity, measured by the C 2 H 2 reduction assay over the growing season. Estimates given by the 15 N measurements were correlated with the C 2 H 2 reducing activity but not with the differences in the N yield. This shows that the isotopic composition was dependent on the amount of fixed nitrogen and consequently that the estimates of fixed nitrogen based on natural 15 N abundance should be reliable. The absence of correlation between estimates based on 15 N content and estimates based on N yield was explained by differences in the uptake of soil nitrogen between inoculated and non inoculated soybeans. (Auth.)

  7. Progress in 15N and 13C separation by isotopic exchange

    International Nuclear Information System (INIS)

    Axente, D.

    2004-01-01

    An experimental study of 15 N separation by isotopic exchange in NO, NO 2 - HNO 3 system under pressure is presented. The pressure increase in 15 N separation plant improved the isotopic transport between the two phases circulated in counter-current in the packed column according to a better kinetics of isotopic exchange at higher pressures. The operation of 15 N separation plant at a pressure of 1.8 atm (absolute) will permit doubling of 10 M nitric acid flow rate and of 15 N production of a given column. The improved performance at a higher pressure is significant for large scale 15 N production, which would be utilized for uranium nitride fuels for FBRs. Enrichment of 13 C by chemical exchange between CO 2 and amine carbamate in nonaqueous solvent has been modelled. For process optimization the steady state separation and the height equivalent to a theoretical plate (HETP) have been determined for different experimental conditions and simulated for higher pressures than atmospheric one. At lower temperature (5 deg C) as the pressure increases the quantity of CO 2 dissolved in amine solution increases. For process analysis at higher pressures and lower temperatures, the two steps model has been considered. At 0.9 MPa pressure and 5 deg C the reaction rate is higher than at 25 deg C and atmospheric pressure, the value of HETP being lower with more than 100% than at 25 deg C. (author)

  8. Fate of {sup 15}N-urea applied to wheat-soybean succession crop

    Energy Technology Data Exchange (ETDEWEB)

    Boaretto, Antonio Enedi; Trivelin, Paulo Cesar Ocheuze; Muraoka, Takashi [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)]. E-mail: aeboaret@cena.usp.br; pcotrive@cena.usp.br; muraoka@cena.usp.br; Spolidorio, Eduardo Scarpari [SN Centro de Pesquisa e Promocao de Sulfato de Amonio, Piracicaba, SP (Brazil)]. E-mail: sncentro@merconet.com.br; Freitas, Jose Guilherme de; Cantarella, Heitor [Instituto Agronomico de Campinas, SP (Brazil)]. E-mail: jfreitas@iac.sp.gov.br; hcantare@iac.sp.gov.br

    2004-07-01

    The wheat crop in Sao Paulo State, Brazil, is fertilized with N, P and K. The rate of applied N (0 to 120 kg.ha{sup -1}) depends on the previous grown crop and the irrigation possibility. The response of wheat to rates and time of N application and the fate of N applied to irrigated wheat were studied during two years. Residual N recovery by soybean grown after the wheat was also studied. The maximum grain productivity was obtained with 92 kg.ha{sup -1} of N. The efficiency of {sup 15}N-urea utilization ranged from 52% to 85%. The main loss of applied {sup 15} N, 5% to 12% occurred as ammonia volatilized from urea applied on soil surface. The N loss by leaching even at the N rate of 135 kg.ha{sup -1}, was less than 1% of applied {sup 15}N, due to the low amount of rainfall during the wheat grown season and a controlled amount of irrigated water, that were sufficient to moisten only the wheat root zone. The residual {sup 15} N after wheat harvest represents around 40% of N applied as urea: 20% in soil, 3% in wheat root system and 16% in the wheat straw. Soybean recovered less than 2% of the {sup 15} N applied to wheat at sowing or at tillering stage. (author)

  9. Fate of 15N-urea applied to wheat-soybean succession crop

    International Nuclear Information System (INIS)

    Boaretto, Antonio Enedi; Trivelin, Paulo Cesar Ocheuze; Muraoka, Takashi; Spolidorio, Eduardo Scarpari; Freitas, Jose Guilherme de; Cantarella, Heitor

    2004-01-01

    The wheat crop in Sao Paulo State, Brazil, is fertilized with N, P and K. The rate of applied N (0 to 120 kg.ha -1 ) depends on the previous grown crop and the irrigation possibility. The response of wheat to rates and time of N application and the fate of N applied to irrigated wheat were studied during two years. Residual N recovery by soybean grown after the wheat was also studied. The maximum grain productivity was obtained with 92 kg.ha -1 of N. The efficiency of 15 N-urea utilization ranged from 52% to 85%. The main loss of applied 15 N, 5% to 12% occurred as ammonia volatilized from urea applied on soil surface. The N loss by leaching even at the N rate of 135 kg.ha -1 , was less than 1% of applied 15 N, due to the low amount of rainfall during the wheat grown season and a controlled amount of irrigated water, that were sufficient to moisten only the wheat root zone. The residual 15 N after wheat harvest represents around 40% of N applied as urea: 20% in soil, 3% in wheat root system and 16% in the wheat straw. Soybean recovered less than 2% of the 15 N applied to wheat at sowing or at tillering stage. (author)

  10. Evidence for the involvement of VAR2CSA in pregnancy-associated malaria

    DEFF Research Database (Denmark)

    Salanti, Ali; Dahlbäck, Madeleine; Turner, Louise

    2004-01-01

    to chondroitin sulfate A (CSA). Parasites causing PAM express unique VSA types, VSAPAM, which can be serologically classified as sex specific and parity dependent. It is sex specific because men from malaria-endemic areas do not develop VSAPAM antibodies; it is parity dependent because women acquire anti......In Plasmodium falciparum-endemic areas, pregnancy-associated malaria (PAM) is an important health problem. The condition is precipitated by accumulation of parasite-infected erythrocytes (IEs) in the placenta, and this process is mediated by parasite-encoded variant surface antigens (VSA) binding...

  11. Control Presupuestario de Ventas del departamento de CSA de la empresa KONEKFACE, S.A.

    OpenAIRE

    Álvarez Wilmanski, Carlos

    2005-01-01

    La Dirección de la empresa KONEKFACE, S.A., fabricante de componentes eléctricos y electrónicos para conexionado, decidió hace dos años montar un departamento para suministrar productos considerados “no standart”. Dicha decisión fue tomada por la dirección de la empresa ya que se observó que los clientes eran cada vez más exigentes y demandaban cada vez más flexibilidad a sus productos. Se creó así el departamento de CSA (Customer Specific Assemblies), cuyas siglas significan M...

  12. Isotopic determination by optical spectroscopy of low isotopic 15N compounds

    International Nuclear Information System (INIS)

    Guiraud, G.; Fardeau, J.C.

    1980-01-01

    Due to its far lower cost concerning the equipment as well as the functioning requirements, optical spectroscopy is more and more utilized rather than mass spectrometry in nitrogen isotopic analysis. The present technical paper refers to a newly-devised apparatus and also to the technics associated to its operation. In the GS 1 model a concave grating is used as light scattering system and the wavelengths corresponding to masses 28( 14 N 14 N), 29( 14 N 15 N) and 30( 15 N 15 N) are scanned by the rotation of parallel plates. The preparation of the electrodeless discharge tubes is described and the best experimental conditions are given. It is necessary to draw a calibration curve but then measurements are extremely accurate even for very low isotopic enrichments (lower than 0.3%) [fr

  13. A density functional study of 15N chemical shielding tensors in quinolines

    Science.gov (United States)

    Behzadi, Hadi; Esrafili, Mehdi D.; Beheshtian, Javad; Hadipour, Nasser L.; van der Spoel, David

    2009-07-01

    DFT calculations were carried out to characterize the 15N shielding tensors in quinolines. This computational study is intended to shed light on the differences between two groups of quinolines: series A (7-chloro 4-aminoalkyls quinolines) and series B (quinolines, 3-, 5-, 6-, 8-amino quinolines and 4,8-dichloro quinoline). Unlike the quinolines in series B, the series A quinolines show considerable β-hematin inhibition activity which is essential for quinoline-based drugs. The results show that the substitution position significantly affects the σ11 and σ22 components of 15N shielding tensors of quinolines. The 15N shielding components are noticeably different for the two series and can be related to their ability to interact with hematin.

  14. Origin and tracing techniques of high 15N nitrogen compounds in industrial environments

    International Nuclear Information System (INIS)

    Talma, A.S.; Meyer, R.

    2002-01-01

    Effluents and process waters from various industrial plants were investigated for the 15 N/ 14 N isotope ratio in nitrate and ammonia. It was found that large isotope fractionation occurs in cases where ammonia is involved in gas-liquid phase changes. This feature was found to occur in two coke oven plants where ammonia gas is removed from a gas stream by solution in water, in an ammonia sulphate plant where ammonia gas is absorbed in sulphuric acid and in a water treatment plant where ammonia is removed from (high pH) water by blowing air through the process water. In all these cases 15 N isotope enrichments (in the range of 10 to 30 per mille) occurred. These enrichments are in excess of those found naturally. Ammonia in such wastewaters essentially retains this high 15 N content when it is converted to nitrate underground: which occurs rapidly under well-oxidised conditions. Nitrate is a fairly conservative tracer and its contamination in water can be followed readily. In the low recharge environment in the central parts of South Africa evidence of waste management practices of 10-20 years earlier were still quite evident using this isotopic label. The high 15 N nitrate signal could be used to distinguish industrial nitrogen pollution from pollution by local sewage disposal systems. Vegetation that derives its nitrogen from such high 15 N sources retains the isotope signature of its source. Grass and other annual plants then exhibit the isotope signature of the water of a specific year. Trees exhibit the isotope signature of deeper water, which shows the effects of longer term pollution events. The use of high 15 N as tracer enables the source apportionment of nitrogen derived pollution in these specific circumstances. (author)

  15. Belowground fate of (15)N injected into sweetgum trees (Liquidambar styraciflua) at the ORNL FACE Experiment.

    Science.gov (United States)

    Garten, Charles T; Brice, Deanne J

    2009-10-01

    Nitrogen (N) cycling can be an important constraint on forest ecosystem response to elevated atmospheric CO(2). Our objective was to trace the movement of (15)N, injected into tree sap, to labile and stable forms of soil organic matter derived partly from the turnover of tree roots under elevated (545 ppm) and ambient (394 ppm) atmospheric CO(2) concentrations at the Oak Ridge National Laboratory (ORNL) FACE (Free-Air Carbon Dioxide Enrichment) Experiment. Twenty-four sweetgum trees, divided equally between CO(2) treatments, were injected with 3.2 g (15)N-ammonium sulfate (99 atom %), and soil samples were collected beneath the trees over a period of 89 weeks. For 16 cm deep soil samples collected beneath the study trees, there was 28% more fine root (less than or equal to 2 mm diameter) biomass under elevated CO(2) (P = 0.001), but no significant treatment effect on the amounts of necromass, coarse root biomass, or on the N concentrations in tree roots and necromass. Nitrogen-15 moved quickly into roots from the stem injection site and the (15)N content of roots, necromass, and labile organic matter (i.e. particulate organic matter, POM) increased over time. At 89 weeks post-injection, approximately 76% of the necromass (15)N originated from fine root turnover. Nitrogen-15 in POM had a relatively long turnover time (47 weeks) compared with (15)N in roots (16 to 22 weeks). Over the 1.7 year period of the study, (15)N moved from roots into slower cycling POM and the disparity in turnover times between root N and N in POM could impose progressive limitations on soil N availability with stand maturation irrespective of atmospheric CO(2), especially if the release of N through the decomposition of POM is essential to sustain forest net primary production. Published in 2009 by John Wiley & Sons, Ltd.

  16. Nitrate reductase 15N discrimination in Arabidopsis thaliana, Zea mays, Aspergillus niger, Pichea angusta, and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Eli eCarlisle

    2014-07-01

    Full Text Available Stable 15N isotopes have been used to examine movement of nitrogen (N through various pools of the global N cycle. A central reaction in the cycle involves nitrate (NO3– reduction to nitrite (NO2– catalyzed via nitrate reductase (NR. Discrimination against 15N by NR is a major determinant of isotopic differences among N pools. Here, we measured in vitro 15N discrimination by several NRs purified from plants, fungi, and a bacterium to determine the intrinsic 15N discrimination by the enzyme and to evaluate the validity of measurements made using 15N-enriched NO3–. Observed NR isotope discrimination ranged from 22‰ to 32‰ (kinetic isotope effects of 1.022 to 1.032 among the different isozymes at natural abundance 15N (0.37%. As the fractional 15N content of substrate NO3– increased from natural abundance, the product 15N fraction deviated significantly from that expected based on substrate enrichment and 15N discrimination measured at natural abundance. Additionally, isotopic discrimination by denitrifying bacteria used to reduce NO3– and NO2– in some protocols became a greater source of error as 15N enrichment increased. We briefly discuss potential causes of artifactual results with enriched 15N and recommend against the use of highly enriched 15N tracers to study N discrimination in plants or soils.

  17. 15N Fractionation in Star-Forming Regions and Solar System Objects

    Science.gov (United States)

    Wirstrom, Eva; Milam, Stefanie; Adande, GIlles; Charnley, Steven; Cordiner, Martin

    2015-01-01

    A central issue for understanding the formation and evolution of matter in the early Solar System is the relationship between the chemical composition of star-forming interstellar clouds and that of primitive Solar System materials. The pristinemolecular content of comets, interplanetary dust particles and carbonaceous chondrites show significant bulk nitrogen isotopic fractionation relative to the solar value, 14N15N 440. In addition, high spatial resolution measurements in primitive materials locally show even more extreme enhancements of 14N15N 100.

  18. Constraints on oceanic N balance/imbalance from sedimentary 15N records

    Science.gov (United States)

    Altabet, M. A.

    2007-01-01

    According to current best estimates, the modern ocean's N cycle is in severe deficit. N isotope budgeting provides an independent geochemical constraint in this regard as well as the only means for past reconstruction. Overall, it is the relative proportion of N2 fixation consumed by water column denitrification that sets average oceanic δ15N under steady-state conditions. Several factors (conversion of organic N to N2, Rayleigh closed and open system effects) likely reduce the effective fractionation factor (ɛ) for water column denitrification to about half the inherent microbial value for ɛden. If so, the average oceanic δ15N of ~5‰ is consistent with a canonical contribution from water column denitrification of 50% of the source flux from N2 fixation. If an imbalance in oceanic N sources and sinks changes this proportion then a transient in average oceanic δ15N would occur. Using a simple model, changing water column denitrification by ±30% or N2 fixation by ±15% produces detectable (>1‰) changes in average oceanic δ15N over one residence time period or more with corresponding changes in oceanic N inventory. Changing sedimentary denitrification produces no change in δ15N but does change N inventory. Sediment δ15N records from sites thought to be sensitive to oceanic average δ15N all show no detectible change over the last 3 kyr or so implying a balanced marine N budget over the latest Holocene. A mismatch in time scales is the most likely meaningful interpretation of the apparent conflict with modern flux estimates. Decadal to centennial scale oscillations between net N deficit and net surplus may occur but on the N residence timescale of several thousand years, net balance is achieved in sum. However, sediment δ15N records from the literature covering the period since the last glacial maximum show excursions of up to several ‰ that are consistent with sustained N deficit during the deglaciation followed by readjustment and establishment of

  19. Constraints on oceanic N balance/imbalance from sedimentary 15N records

    Directory of Open Access Journals (Sweden)

    M. A. Altabet

    2007-01-01

    Full Text Available According to current best estimates, the modern ocean's N cycle is in severe deficit. N isotope budgeting provides an independent geochemical constraint in this regard as well as the only means for past reconstruction. Overall, it is the relative proportion of N2 fixation consumed by water column denitrification that sets average oceanic δ15N under steady-state conditions. Several factors (conversion of organic N to N2, Rayleigh closed and open system effects likely reduce the effective fractionation factor (ε for water column denitrification to about half the inherent microbial value for εden. If so, the average oceanic δ15N of ~5‰ is consistent with a canonical contribution from water column denitrification of 50% of the source flux from N2 fixation. If an imbalance in oceanic N sources and sinks changes this proportion then a transient in average oceanic δ15N would occur. Using a simple model, changing water column denitrification by ±30% or N2 fixation by ±15% produces detectable (>1‰ changes in average oceanic δ15N over one residence time period or more with corresponding changes in oceanic N inventory. Changing sedimentary denitrification produces no change in δ15N but does change N inventory. Sediment δ15N records from sites thought to be sensitive to oceanic average δ15N all show no detectible change over the last 3 kyr or so implying a balanced marine N budget over the latest Holocene. A mismatch in time scales is the most likely meaningful interpretation of the apparent conflict with modern flux estimates. Decadal to centennial scale oscillations between net N deficit and net surplus may occur but on the N residence timescale of several thousand years, net balance is achieved in sum. However, sediment δ15N records from the literature covering the period since the last glacial maximum show excursions of up to several ‰ that are consistent with sustained N deficit during the deglaciation followed by readjustment

  20. Evaluation of (+)-p-[11C]methylvesamicol for mapping sigma1 receptors: a comparison with [11C]SA4503

    International Nuclear Information System (INIS)

    Ishiwata, Kiichi; Kawamura, Kazunori; Yajima, Kazuyoshi; QingGeLeTu; Mori, Hirofumi; Shiba, Kazuhiro

    2006-01-01

    Vesamicol is a leading compound for positron emission tomography (PET) and single photon emission computed tomography (SPECT) tracers for mapping the vesicular acetylcholine transporter (VAChT). Recently, we found that (+)-p-methylvesamicol ((+)-PMV) has low affinity for VAChT (K i =199 nM), but has moderate to high affinity for sigma receptors: K i =3.0 nM for sigma 1 and K i =40.7 nM for sigma 2 , and that sigma 1 -selective SA4503 (K i =4.4 nM for sigma 1 and K i =242 nM for sigma 2 ) has moderate affinity for VAChT (K i =50.2 nM). In the present study, we examined the potential of (+)-[ 11 C]PMV as a PET radioligand for mapping sigma 1 receptors as compared with [ 11 C]SA4503. In rat brain, similar regional distribution patterns of (+)-[ 11 C]PMV and [ 11 C]SA4503 were shown by tissue dissection and by ex vivo autoradiography. Blocking experiments using (±)-PMV (-)-vesamicol, SA4503, haloperidol and (±)-pentazocine showed that the two tracers specifically bound to sigma 1 receptors, and that [ 11 C]SA4503 exhibited greater specific binding than (+)-[ 11 C]PMV. No sign of VAChT-specific binding by [ 11 C]SA4503 was observed in the striatum, which is rich in VAChT sites. In conclusion, (+)-[ 11 C]PMV specifically bound to sigma 1 receptors in the brain, but to a lesser extent than [ 11 C]SA4503, suggesting that (+)-[ 11 C]PMV is a less preferable PET ligand than [ 11 C]SA4503. On the other hand, the moderate affinity of [ 11 C]SA4503 for VAChT is negligible in vivo

  1. Study of the GDR in 15N using fast neutron capture

    International Nuclear Information System (INIS)

    Wender, S.A.; Jensen, M.; Potokar, M.; Roberson, N.R.; Tilley, D.R.; Weller, H.R.

    1978-01-01

    The excitation function for 15 N(γ,n) from 16 to 23 MeV was obtained by use of the detailed balance priinciple from neutron capture. As coefficients from the 14 N(n,γ) data are also shown. Similar data are shown for 14 C(p,γ) and 14 N(p,γ) studies. 2 figures

  2. Impact of seaweed beachings on dynamics of δ15N isotopic signatures in marine macroalgae

    International Nuclear Information System (INIS)

    Lemesle, Stéphanie; Mussio, Isabelle; Rusig, Anne-Marie; Menet-Nédélec, Florence; Claquin, Pascal

    2015-01-01

    Highlights: • Two coastal sites (COU, GM) in the Bay of Seine affected by summer seaweed beachings. • The same temporal dynamics of the algal δ 15 N at the two sites. • N and P concentrations in seawater of the two sites dominated by riverine sources. • A coupling between seaweed beachings and N sources of intertidal macroalgae. - Abstract: A fine-scale survey of δ 15 N, δ 13 C, tissue-N in seaweeds was conducted using samples from 17 sampling points at two sites (Grandcamp-Maisy (GM), Courseulles/Mer (COU)) along the French coast of the English Channel in 2012 and 2013. Partial triadic analysis was performed on the parameter data sets and revealed the functioning of three areas: one estuary (EstA) and two rocky areas (GM ∗ , COU ∗ ). In contrast to oceanic and anthropogenic reference points similar temporal dynamics characterized δ 15 N signatures and N contents at GM ∗ and COU ∗ . Nutrient dynamics were similar: the N-concentrations in seawater originated from the River Seine and local coastal rivers while P-concentrations mainly from these local rivers. δ 15 N at GM ∗ were linked to turbidity suggesting inputs of autochthonous organic matter from large-scale summer seaweed beachings made up of a mixture of Rhodophyta, Phaeophyta and Chlorophyta species. This study highlights the coupling between seaweed beachings and nitrogen sources of intertidal macroalgae

  3. Backbone dynamics of the EIAV-Tat protein from {sup 15}N relaxation studies

    Energy Technology Data Exchange (ETDEWEB)

    Ejchart, A.; Herrmann, F.; Roesch, P.; Sticht, H.; Willbold, D. [Bayreuth Univ., Bayreuth (Germany)

    1994-12-31

    The work investigates the mobility of EIAV-Tat protein backbone by measuring the relaxation parameters of the {sup 15}N nitrogens. High degree of the flexibility, non-typical of rigid, well structured proteins was shown. 3 refs, 2 figs.

  4. δ15N as a proxy for historic anthropogenic nitrogen loading in Charleston Harbor, SC, USA

    Science.gov (United States)

    Payne, T. N.; Andrus, C. F. T.

    2015-12-01

    Bivalve shell geochemistry can serve as a useful indicator of changes in coastal environments. There is increasing interest in developing paleoenvironmental proxies from mollusk shell organic components. Numerous studies have focused on how the δ15N obtained from bivalve tissues can be used to trace present-day wastewater input into estuaries. However, comparatively little attention has been paid to tracing the impact of anthropogenic nitrogen loading into estuaries over time. By measuring historic levels of δ15N in the organic fraction of oyster shells (Crassostrea virginica) from archaeological sites around Charleston Harbor and comparing those levels to the δ15N content of modern shells, it is possible to assess how nitrogen has fluctuated historically in the area. Whole-shell samples from the Late Archaic Period (~3000-4000 BP, Late Woodland Period (~1400-800 BP), 18th and 19th centuries, and modern controls were measured for %N and d15N. Evidence of increased anthropogenic input of N is expected to begin in the early historic period based on similar analysis in Chesapeake Bay. More ancient samples may give insight into baseline conditions prior to recent population growth and industrialization. This information could help understand how large-scale anthropogenic nitrogen loading has affected coastal ecosystems over time and guide future remediation. Furthermore, this project will help refine and improve this novel proxy of past environmental conditions.

  5. Use of low enriched 15N2 for symbiotic fixation tests

    International Nuclear Information System (INIS)

    Victoria, R.L.

    1975-01-01

    Gaseous atmospheres containing 15 N 2 with low enrichment were used to test symbiotic nitrogen fixation in beans (Phaseolus vulgari, L.). The tests of fixation in nodulated roots and the tests of fixation in the whole plant, in which the plants were placed inside a specially constructed growth chamber, gave positive results and suggest that the methodology used can be very helpfull in more detailed studies on symbiotic fixation. Samples of atmospheric air were purified by absorption of O 2 and CO 2 by two methods. The purified N 2 obtained was analysed and the results were compared. Samples of bean plant material were collected in natural conditions and analysed for 15 N natural variation. Several samples were prepared for 15 N isotopic analysis by two methods. The results obtained were compared. All samples were analysed in an Atlas-Varian Ch-4 model mass spectrometer, and the results were given in delta 15 N 0 / 00 variation in relation to a standard gas

  6. Fast hydrogen exchange affects 15N relaxation measurements in intrinsically disordered proteins

    International Nuclear Information System (INIS)

    Kim, Seho; Wu, Kuen-Phon; Baum, Jean

    2013-01-01

    Unprotected amide protons can undergo fast hydrogen exchange (HX) with protons from the solvent. Generally, NMR experiments using the out-and-back coherence transfer with amide proton detection are affected by fast HX and result in reduced signal intensity. When one of these experiments, 1 H– 15 N HSQC, is used to measure the 15 N transverse relaxation rate (R 2 ), the measured R 2 rate is convoluted with the HX rate (k HX ) and has higher apparent R 2 values. Since the 15 N R 2 measurement is important for analyzing protein backbone dynamics, the HX effect on the R 2 measurement is investigated and described here by multi-exponential signal decay. We demonstrate these effects by performing 15 N R 2 CPMG experiments on α-synuclein, an intrinsically disordered protein, in which the amide protons are exposed to solvent. We show that the HX effect on R 2 CPMG can be extracted by the derived equation. In conclusion, the HX effect may be pulse sequence specific and results from various sources including the J coupling evolution, the change of steady state water proton magnetization, and the D 2 O content in the sample. To avoid the HX effect on the analysis of relaxation data of unprotected amides, it is suggested that NMR experimental conditions insensitive to the HX should be considered or that intrinsic R 2 CPMG values be obtained by methods described herein.

  7. Quantifying the production of dissolved organic nitrogen in headwater streams using 15N tracer additions

    Science.gov (United States)

    Laura T. Johnson; Jennifer L. Tank; Robert O. Hall; Patrick J. Mullholland; Stephen K. Hamilton; H. Maurice Valett; Jackson R. Webster; Melody J. Bernot; William H. McDowell; Bruce J. Peterson; Suzanne M. Thomas

    2013-01-01

    Most nitrogen (N) assimilation in lake and marine ecosystems is often subsequently released via autochthonous dissolved organic nitrogen (DON) production, but autochthonous DON production has yet to be quantified in flowing waters. We measured in-stream DON production following 24 h 15N-nitrate (NO3-...

  8. Monitoring the refinement of crystal structures with 15N solid-state NMR shift tensor data

    Science.gov (United States)

    Kalakewich, Keyton; Iuliucci, Robbie; Mueller, Karl T.; Eloranta, Harriet; Harper, James K.

    2015-11-01

    The 15N chemical shift tensor is shown to be extremely sensitive to lattice structure and a powerful metric for monitoring density functional theory refinements of crystal structures. These refinements include lattice effects and are applied here to five crystal structures. All structures improve based on a better agreement between experimental and calculated 15N tensors, with an average improvement of 47.0 ppm. Structural improvement is further indicated by a decrease in forces on the atoms by 2-3 orders of magnitude and a greater similarity in atom positions to neutron diffraction structures. These refinements change bond lengths by more than the diffraction errors including adjustments to X-Y and X-H bonds (X, Y = C, N, and O) of 0.028 ± 0.002 Å and 0.144 ± 0.036 Å, respectively. The acquisition of 15N tensors at natural abundance is challenging and this limitation is overcome by improved 1H decoupling in the FIREMAT method. This decoupling dramatically narrows linewidths, improves signal-to-noise by up to 317%, and significantly improves the accuracy of measured tensors. A total of 39 tensors are measured with shifts distributed over a range of more than 400 ppm. Overall, experimental 15N tensors are at least 5 times more sensitive to crystal structure than 13C tensors due to nitrogen's greater polarizability and larger range of chemical shifts.

  9. Can δ15N and δ13C stable isotopes and fatty acid signatures ...

    African Journals Online (AJOL)

    Temporal changes in fatty acid composition and δ15N, δ13C stable isotope values of the phytobenthos growing on artificial clay substrates under natural conditions over a 28-day period at an upstream and a downstream site in the Kowie River near Grahamstown were investigated in 2012. High concentrations of diatom ...

  10. Estimation of nitrogen fixation in Leucaena leucocephala using 15N-enrichment methodologies

    Science.gov (United States)

    John A. Parrotta; Dwight D. Baker; Maurice Fried

    1994-01-01

    An estimation of biological nitrogen fixation by Leucaena leucocephala (Lam.) de Wit in monoculture and mixed-species plantations (with Casuarina equisetifolia L. ex J.R. & G. Forst., and Eucalyptus robusta Sm.) was undertaken over a two-year period in Puerto Rico using the 15N-enrichment...

  11. Application of 15N-enrichment methodologies to estimate nitrogen fixation in Casuarina equisetifolia

    Science.gov (United States)

    John A. Parrotta; Dwight D. Baker; Maurice Fried

    1994-01-01

    The 15N-enrichment technique for estimating biological nitrogen fixation in Casuarina equisetifolia J.R. & G. Forst. was evaluated under field conditions in single-species and mixed-species plantings (with a nonfixing reference species, Eucalyptus X robusta J.E. Smith) between...

  12. Pathways of nitrogen assimilation in cowpea nodules studied using 15N2 and allopurinol

    International Nuclear Information System (INIS)

    Atkins, C.A.; Storer, P.J.; Pate, J.S.

    1988-01-01

    In the presence of 0.5 millimolar allopurinol (4-hydroxypyrazolo [3,4-d]pyrimidine), an inhibitor of NAD:xanthine oxidoreductase (EC 1.2.3.2), intact attached nodules of cowpea (vigna unguiculata L. Walp. cv Vita 3) formed [ 15 N]xanthine from 15 N 2 at rates equivalent to those of ureide synthesis, confirming the direct assimilation of fixed nitrogen into purines. Xanthine accumulated in nodules and was exported in increasing amounts in xylem of allopurinol-treated plants. Other intermediates of purine oxidation, de novo purine synthesis, and ammonia assimilation did not increase and, over the time course of experiments (4 hours), allopurinol had no effect on nitrogenase (EC 1.87.99.2) activity. Negligible 15 N -labeling of asparagine from 15 N 2 was observed, suggesting that the significant pool (up to 14 micromoles per gram of nodule fresh weight) of this amide in cowpea nodules was not formed directly from fixation but may have accumulated as a consequence of phloem delivery

  13. Measurement of marine productivity using 15 N and 13 C tracers ...

    Indian Academy of Sciences (India)

    Difference in energy requirement for assimilation of different nitrogen compounds decides the preferred nitrogen source during the early hours of incubation. Variation in light intensity during incubation also plays a significant role in the assimilation of nitrogen. Results from time course experiments with both 15N and 13C ...

  14. Regional assessment of N saturation using foliar and root δ15N

    Science.gov (United States)

    L.H. Pardo; P.H. Templer; C.L. Goodale; S. Duke; P.M. Groffman; M.B. Adams; P. Boeckx; J. Boggs; J. Campbell; B. Colman; J. Compton; B. Emmett; P. Gundersen; J. Kjonaas; G. Lovett; M. Mack; A. Magill; M. Mbila; M.J. Mitchell; G. McGee; S. McNulty; K. Nadelhoffer; S. Ollinger; D. Ross; H. Rueth; L. Rustad; P. Schaberg; S. Schiff; P. Schleppi; J. Spoelstra; W. Wessel

    2006-01-01

    N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar δ15N may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root δ

  15. Monitoring the refinement of crystal structures with (15)N solid-state NMR shift tensor data.

    Science.gov (United States)

    Kalakewich, Keyton; Iuliucci, Robbie; Mueller, Karl T; Eloranta, Harriet; Harper, James K

    2015-11-21

    The (15)N chemical shift tensor is shown to be extremely sensitive to lattice structure and a powerful metric for monitoring density functional theory refinements of crystal structures. These refinements include lattice effects and are applied here to five crystal structures. All structures improve based on a better agreement between experimental and calculated (15)N tensors, with an average improvement of 47.0 ppm. Structural improvement is further indicated by a decrease in forces on the atoms by 2-3 orders of magnitude and a greater similarity in atom positions to neutron diffraction structures. These refinements change bond lengths by more than the diffraction errors including adjustments to X-Y and X-H bonds (X, Y = C, N, and O) of 0.028 ± 0.002 Å and 0.144 ± 0.036 Å, respectively. The acquisition of (15)N tensors at natural abundance is challenging and this limitation is overcome by improved (1)H decoupling in the FIREMAT method. This decoupling dramatically narrows linewidths, improves signal-to-noise by up to 317%, and significantly improves the accuracy of measured tensors. A total of 39 tensors are measured with shifts distributed over a range of more than 400 ppm. Overall, experimental (15)N tensors are at least 5 times more sensitive to crystal structure than (13)C tensors due to nitrogen's greater polarizability and larger range of chemical shifts.

  16. 948 15 N as a tool to demonstrate the contribution of fish-waste ...

    African Journals Online (AJOL)

    This study uses stable isotope ratios of nitrogen (ä15N) to test the hypothesis that a bloom of the green seaweed Ulva lactuca, which occurred in Saldanha Bay, South Africa, in summer 1993/94 was linked to an adjacent discharge of nitrogen from pelagic fish processing waste. It is suggested that only two significant ...

  17. 15 N utilization in nitride nuclear fuels for advanced nuclear power reactors and accelerator - driven systems

    International Nuclear Information System (INIS)

    Axente, D.

    2005-01-01

    15 N utilization for nitride nuclear fuels production for nuclear power reactors and accelerator - driven systems is presented. Nitride nuclear fuel is the obvious choice for advanced nuclear reactors and ADS because of its favorable properties: a high melting point, excellent thermal conductivity, high fissile density, lower fission gas release and good radiation tolerance. The application of nitride fuels in nuclear reactors and ADS requires use of 15 N enriched nitrogen to suppress 14 C production due to (n,p) reaction on 14 N. Accelerator - driven system is a recent development merging of accelerator and fission reactor technologies to generate electricity and transmute long - lived radioactive wastes as minor actinides: Np, Am, Cm. A high-energy proton beam hitting a heavy metal target produces neutrons by spallation. The neutrons cause fission in the fuel, but unlike in conventional reactors, the fuel is sub-critical and fission ceases when the accelerator is turned off. Nitride fuel is a promising candidate for transmutation in ADS of minor actinides, which are converted into nitrides with 15 N for that purpose. Tacking into account that the world wide market is about 20 to 40 Kg 15 N annually, the supply of that isotope for nitride fuel production for nuclear power reactors and ADS would therefore demand an increase in production capacity by a factor of 1000. For an industrial plant producing 100 t/y 15 N, using present technology of isotopic exchange in NITROX system, the first separation stage of the cascade would be fed with 10M HNO 3 solution of 600 mc/h flow - rate. If conversion of HNO 3 into NO, NO 2 , at the enriching end of the columns, would be done with gaseous SO 2 , for a production plant of 100 t/y 15 N a consumption of 4 million t SO 2 /y and a production of 70 % H 2 SO 4 waste solution of 4.5 million mc/y are estimated. The reconversion of H 2 SO 4 into SO 2 in order to recycle of SO 2 is a problem to be solved to compensate the cost of SO 2

  18. Identification of a Major Dimorphic Region in the Functionally Critical N-Terminal ID1 Domain of VAR2CSA.

    Directory of Open Access Journals (Sweden)

    Justin Doritchamou

    Full Text Available The VAR2CSA protein of Plasmodium falciparum is transported to and expressed on the infected erythrocyte surface where it plays a key role in placental malaria (PM. It is the current leading candidate for a vaccine to prevent PM. However, the antigenic polymorphism integral to VAR2CSA poses a challenge for vaccine development. Based on detailed analysis of polymorphisms in the sequence of its ligand-binding N-terminal region, currently the main focus for vaccine development, we assessed var2csa from parasite isolates infecting pregnant women. The results reveal for the first time the presence of a major dimorphic region in the functionally critical N-terminal ID1 domain. Parasite isolates expressing VAR2CSA with particular motifs present within this domain are associated with gravidity- and parasite density-related effects. These observations are of particular interest in guiding efforts with respect to optimization of the VAR2CSA-based vaccines currently under development.

  19. Application time of nitrogen fertilizer 15N by a potato crop (Solanum Tuberosum L.)

    International Nuclear Information System (INIS)

    Bastidas, O.G.; Urquiaga, S.

    1987-01-01

    This study was performed at the ''San Jorge'' experimental farm of the Instituto Colombiano Agropecuario (ICA), Bogota, Colombia. The study was performed to investigate the effect of timing of application of nitrogen fertilizer on the productivity of, and the efficiency of utilization of 15 N-labelled fertilizer by, a potato crop (Solanum tuberosum L.), cv. Tequendama. The crop was fertilized with 100, 200 and 100 Kg/ha -1 of N, P 2 O 5 and K 2 O respectively. The N fertilizers were either added as 15 N labelled urea (2.955 at.% 15 N excess) or as labelled ammonium sulphate (2.071 at.% 15 N excess). In all treatments with nitrogen, a total of 100 Kg N ha -1 was added, but the nitrogen was added either in two or three split doses (only one dose being labelled with 15 N) at the following times: at planting, 35 days after emergence (DAE) and/or 60 DAE. It was found that: a) Nitrogen fertilization increased tuber production from 24 to 43 t/ha -1 ; b) The tubers constituted approximately 80% of total plant dry matter and 70% of the total nitrogen and fertilizer N accumulated by the plant; c) The fertilizer use efficiency varied between 49 and 68%, and the highest efficiency occurred when the nitrogen was split in three doses; d) The urea and ammonium sulphate gave similar results in all parameters evaluated; e) When the total nitrogen difference method was applied to interpretation of the results the fertilizer use efficiency was overestimated by 15 to 30%

  20. Distribution of 15N-labeled urea injected into field-grown corn plants

    International Nuclear Information System (INIS)

    Zhou, X.; Madrmootoo, C.A.; Mackenzie, A.F.; Smith, D.L.

    1998-01-01

    Nitrogen (N) assimilate supply to developing corn (Zea mays L.) ears plays a critical role in grain dry weight accumulation. The use of stem-perfused/injected 15N labeled compounds to determine the effects of an artificial N source on the subsequent distribution of injected N and grain weight of field-grown corn plants has not been reported previously. Our objective was to assess the distribution of N added via an artificial source. Three soil N fertilizer levels (0, 180, and 270 kg N ha-1) and three N solutions (distilled water control and 15N enriched urea at 15 and 30 mM N) were arranged in a split-plot design. Three N concentrations were injected using a pressurized stem injection technique. The injection started fifteen days after silking and continued until immediately prior to plant physiological maturity. The average uptake volume was 256 mL over the 30-day injection period. The N supplied via injection represented 1.5 to 3% of the total plant N. Neither soil applied N fertilizer nor injected N altered dry matter distribution among plant tissues. As the concentration of N in the injected solutions increased, N concentrations increased in the grain and upper stalks, and % 15N atom excess in ear+1 leaves and leaves increased. The relative degree of 15N enrichment for each of the tissues measured was injected internode grain upper stalks leaves lower stalks cob husk ear + 1 leaf ear leaf. This study indicated that the exogenous N supplied via stem-injection, was incorporated into all the measured plant parts, although not uniformly. The distribution of the injected 15N was affected both by the proximity of sinks to the point of injection and the strength of the various sinks

  1. Separation of 15N by isotopic exchange in NO, NO2-HNO3 system under pressure

    International Nuclear Information System (INIS)

    Axente, D.; Baldea, A.; Teaca, C.; Horga, R.; Abrudean, M.

    1998-01-01

    One of the most used method for production of 15 N with 99% at. concentration is the isotopic exchange between gaseous nitrogen oxides and HNO 3 solution 10M: ( 15 NO, 15 NO 2 ) g + H 14 NO 3,l = ( 14 NO, 14 NO 2 ) g + H 15 NO 3,l . The isotopic exchange is characterized by an elemental separation factor α=1.055 at 25 deg. C and atmospheric pressure. Recently, kinetics data pointed to the linear dependence of the exchange rate 15 N/ 14 N(R) on the nitrogen oxide pressure with a rate law R = k[HNO 3 ] 2 · [N 2 O 3 ]. In this work, the influence of the nitrogen oxide pressure on the 15 N separation efficiency was determined by the use of a laboratory equipment with a separation column pack of Helipack type, with dimensions 1.8 mm x 1.8 mm x 0.2 mm. The increase of nitrogen oxide pressure led to a better isotopic transfer between the two counter-flow phases in the column pack. The HETP (Height Equivalent to a Theoretical Plate) determined for a 3.14 ml ·cm -2 · min -1 load is equal to that obtained at atmospheric pressure for a two times lower load. The operation of the equipment for isotopic separation of 15 N at 1.8 atm instead of atmospheric pressure allows doubling the HNO 3 10 M load of the column and consequently, doubling the production rate. A better performance of the separation process at higher pressure is essential for the industrial production of 15 N isotope which is used for the production of uranium nitride in FBR type reactors. (authors)

  2. High avidity antibodies to full-length VAR2CSA correlate with absence of placental malaria.

    Directory of Open Access Journals (Sweden)

    Yeung Lo Tutterrow

    Full Text Available VAR2CSA mediates sequestration of Plasmodium falciparum-infected erythrocytes in the placenta, increasing the risk of poor pregnancy outcomes. Naturally acquired antibodies (Ab to placental parasites at delivery have been associated with improved pregnancy outcomes, but Ab levels and how early in pregnancy Ab must be present in order to eliminate placental parasites before delivery remains unknown. Antibodies to individual Duffy-binding like domains of VAR2CSA have been studied, but the domains lack many of the conformational epitopes present in full-length VAR2CSA (FV2. Thus, the purpose of this study was to describe the acquisition of Ab to FV2 in women residing in high and low transmission areas and determine how Ab levels during pregnancy correlate with clearance of placental parasites. Plasma samples collected monthly throughout pregnancy from pregnant women living in high and low transmission areas in Cameroon were evaluated for Ab to FV2 and the proportion of high avidity Ab (i.e., Ab that remain bound in the presence of 3M NH(4SCN was assessed. Ab levels and proportion of high avidity Ab were compared between women with placental malaria (PM(+ and those without (PM(- at delivery. Results showed that PM(- women had significantly higher Ab levels (p = 0.0047 and proportion of high avidity Ab (p = 0.0009 than PM(+ women throughout pregnancy. Specifically, women with moderate to high Ab levels (>5,000 MFI and those with ≥ 35% high avidity Ab at 5-6 months were found to have 2.3 (95% CI, 1.0-4.9 and 7.6-fold (p = 0.0013, 95% CI: 1.2-50.0 reduced risk of placental malaria, respectively. These data show that high levels of Ab to FV2, particularly those with high avidity for FV2, produced by mid-pregnancy are important in clearing parasites from the placenta. Both high Ab levels and proportion of high avidity Ab to FV2 may serve as correlates of protection for assessing immunity against placental malaria.

  3. The 15N isotope to evaluate fertilizer nitrogen absorption efficiency by the coffee plant

    Directory of Open Access Journals (Sweden)

    Tatiele A.B. Fenilli

    2007-12-01

    Full Text Available The use of the 15N label for agronomic research involving nitrogen (N cycling and the fate of fertilizer-N is well established, however, in the case of long term experimentation with perennial crops like citrus, coffee and rubber tree, there are still shortcomings mainly due to large plant size, sampling procedures, detection levels and interferences on the system. This report tries to contribute methodologically to the design and development of 15N labeled fertilizer experiments, using as an example a coffee crop fertilized with 15N labeled ammonium sulfate, which was followed for two years. The N of the plant derived from the fertilizer was studied in the different parts of the coffee plant in order to evaluate its distribution within the plant and the agronomic efficiency of the fertilizer application practice. An enrichment of the fertilizer-N of the order of 2% 15N abundance was sufficient to study N absorption rates and to establish fertilizer-N balances after one and two years of coffee cropping. The main source of errors in the estimated values lies in the inherent variability among field replicates and not in the measurements of N contents and 15N enrichments of plant material by mass-spectrometry.O uso do traçador 15N em pesquisas agronômicas que envolvem o ciclo do nitrogênio (N e o destino do N do fertilizante está bem estabelecido, entretanto, para o caso de experimentação com plantas perenes como citrus, café e seringueira, ainda existem limitações devidas ao porte das plantas, à amostragem, aos níveis de detecção e à interferência no sistema. Este estudo procura contribuir metodologicamente no delineamento experimental e no desenvolvimento desse tipo de experimentação, em condições de campo, fazendo uso, por dois anos, do experimento de uma cultura de café adubada com fertilizante marcado com 15N. O N da planta derivado do fertilizante foi estudado nas diferentes partes da planta de café para determinar sua

  4. Several domains from VAR2CSA can induce Plasmodium falciparum adhesion-blocking antibodies

    DEFF Research Database (Denmark)

    Salanti, Ali; Resende, Mafalda; Ditlev, Sisse B

    2010-01-01

    ABSTRACT: BACKGROUND: Malaria caused by Plasmodium falciparum can result in several different syndromes with severe clinical consequences for the about 200 million individuals infected each year. During pregnancy, women living in endemic areas become susceptible to malaria due to lack of antibodies...... against a unique P. falciparum membrane protein, named VAR2CSA. This antigen is not expressed in childhood infections, since it binds chondroitin sulphate A (CSA) expressed on the intervillous space in the placenta. A vaccine appears possible because women acquire protective antibodies hindering...... sequestration in the placenta as a function of parity. A challenge for vaccine development is to design small constructs of this large antigen, which can induce broadly protective antibodies. It has previously been shown that one domain of VAR2CSA, DBL4-FCR3, induces parasite adhesion-blocking antibodies...

  5. Variable δ(15N diet-tissue discrimination factors among sharks: implications for trophic position, diet and food web models.

    Directory of Open Access Journals (Sweden)

    Jill A Olin

    Full Text Available The application of stable isotopes to characterize the complexities of a species foraging behavior and trophic relationships is dependent on assumptions of δ(15N diet-tissue discrimination factors (∆(15N. As ∆(15N values have been experimentally shown to vary amongst consumers, tissues and diet composition, resolving appropriate species-specific ∆(15N values can be complex. Given the logistical and ethical challenges of controlled feeding experiments for determining ∆(15N values for large and/or endangered species, our objective was to conduct an assessment of a range of reported ∆(15N values that can hypothetically serve as surrogates for describing the predator-prey relationships of four shark species that feed on prey from different trophic levels (i.e., different mean δ(15N dietary values. Overall, the most suitable species-specific ∆(15N values decreased with increasing dietary-δ(15N values based on stable isotope Bayesian ellipse overlap estimates of shark and the principal prey functional groups contributing to the diet determined from stomach content analyses. Thus, a single ∆(15N value was not supported for this speciose group of marine predatory fishes. For example, the ∆(15N value of 3.7‰ provided the highest percent overlap between prey and predator isotope ellipses for the bonnethead shark (mean diet δ(15N = 9‰ whereas a ∆(15N value < 2.3‰ provided the highest percent overlap between prey and predator isotope ellipses for the white shark (mean diet δ(15N = 15‰. These data corroborate the previously reported inverse ∆(15N-dietary δ(15N relationship when both isotope ellipses of principal prey functional groups and the broader identified diet of each species were considered supporting the adoption of different ∆(15N values that reflect the predators' δ(15N-dietary value. These findings are critical for refining the application of stable isotope modeling approaches as inferences regarding a species

  6. Differential adhesion-inhibitory patterns of antibodies raised against two major variants of the NTS-DBL2X region of VAR2CSA

    DEFF Research Database (Denmark)

    Doritchamou, Justin; Bigey, Pascal; Nielsen, Morten Agertoug

    2013-01-01

    VAR2CSA is a large polymorphic Plasmodium falciparum protein expressed on infected erythrocytes (IE) that allows their binding in the placenta, thus precipitating placental malaria (PM). The N-terminal part of VAR2CSA that contains the binding site to placental chondroitin sulfate A (CSA) is curr......) is currently recognized as the most attractive region for vaccine development. An ultimate challenge is to define epitopes in this region that induce a broad cross-reactive adhesion inhibitory antibody response....

  7. Isotopic variability of cave bears (δ15N, δ13C) across Europe during MIS 3

    Science.gov (United States)

    Krajcarz, Magdalena; Pacher, Martina; Krajcarz, Maciej T.; Laughlan, Lana; Rabeder, Gernot; Sabol, Martin; Wojtal, Piotr; Bocherens, Hervé

    2016-01-01

    Collagen, the organic fraction of bone, records the isotopic parameters of consumed food for carbon (δ13C) and nitrogen (δ15N). This relationship of isotopic signature between diet and tissue is an important tool for the study of dietary preferences of modern and fossil animal species. Since the first information on the isotopic signature of cave bear was reported, numerous data from Europe have become available. The goal of this work is to track the geographical variation of cave bear collagen isotopic values in Europe during Marine Isotopic Stage 3 (about 60,000-25,000 yr BP). In this study the results of new δ13C and δ15N isotopic analyses of cave bear collagen from four Central-Eastern European sites are presented, as well as a review of all published isotopic data for cave bears of the same period. The main conclusion is a lack of geographical East-West pattern in the variations of δ13C and δ15N values of cave bear collagen. Moreover, no relationship was found between cave bear taxonomy and isotopic composition. The cave bears from Central-Eastern Europe exhibit δ13C and δ15N values near the average of the range of Central, Western and Southern European cave bears. Despite the fact that most cave bear sites follow an altitudinal gradient, separate groups of sites exhibit shift in absolute values of δ13C, what disturbs an altitude-related isotopic pattern. The most distinct groups are: high Alpine sites situated over 1500 m a.s.l. - in terms of δ13C; and two Romanian sites Peştera cu Oase and Urşilor - in case of δ15N. Although the cave bear isotopic signature is driven by altitude, the altitudinal adjustment of isotopic data is not enough to explain the isotopic dissimilarity of these cave bears. The unusually high δ15N signature of mentioned Romanian sites is an isolated case in Europe. Cave bears from relatively closely situated Central-Eastern European sites and other Romanian sites are more similar to Western European than to Romanian

  8. Regeneration of Used Frying Palm Oil with Coffee Silverskin (CS), CS Ash (CSA) and Nanoparticles of CS (NCS).

    Science.gov (United States)

    Ismail, Samir Abd-Elmonem A; El-Anany, Ayman Mohammed; Ali, Rehab Farouk M

    2017-01-01

    The present investigation aimed to evaluate the efficiency of coffee silverskin (CS), CS ash (CSA) and nanoparticles of CS (NCS) in regeneration the quality of used frying palm oil. The adsorbents were mixed individually with used frying palm oil at level 4% (w/v) for 60 min. The properties of CS, CSA and NCS adsorbents were studied using (SEM) scanning electron microscopy technique. Some of physico-chemical characteristics of used frying palm oil (UFPO) and UFPO treated with adsorbents were determined. The results showed that the CS ash particles composed of irregular spherical and semispherical grains with deep cavities. The size of particles of CS ash ranged in diameter from 1.1 to 1.7 µm. The morphology of NCS consisted of cluster-type spherical nanoparticles and flakes. The particle size of NCS varies from 0.9 to 1.7 µm. Purification treatments caused marked (poil compared to untreated oil. The treatment of UFPO with 4% of adsorbents caused significant reductions in the content of free fatty acids ranged from 51.2 to 65.0%. The lowest level of peroxide (2.1 meq/kg) was recorded for UFPO treated with 4% of NCS. The highest reductions (72.8; 70.0%) in p-anisidine value were observed in UFPO treated with 4% of CSA and NCS, respectively. Treatment of UFPO with 4% of CS, CSA and NCS significantly lowered the polar content from 13.9% to 6.3, 4.8 and 3.9%, respectively. The results also indicate that CSA and NCS have nearly the same adsorption efficiency in lowering polymer content of UFPO. Filtration treatment of UFPO with 4% of CS, CSA and NCS markedly lowered the viscosity and colour values of treated UFPO.

  9. In vivo evaluation of [11C]SA4503 as a PET ligand for mapping CNS sigma1 receptors

    International Nuclear Information System (INIS)

    Kawamura, Kazunori; Ishiwata, Kiichi; Tajima, Hisashi; Ishii, Shin-Ichi; Matsuno, Kiyoshi; Homma, Yoshio; Senda, Michio

    2000-01-01

    The potential of the 11 C-labeled selective sigma 1 receptor ligand 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine ([ 11 C]SA4503) was evaluated in vivo as a positron emission tomography (PET) ligand for mapping sigma 1 receptors in rats. SA4503 is known to have a high affinity (IC 50 17.4 nM) and a higher selectivity (sigma 1 /sigma 2 =103) for the sigma 1 receptor. A high and increasing brain uptake of [ 11 C]SA4503 was found. Pre-, co- and postinjection of cold SA4503 significantly decreased uptake of [ 11 C]SA4503 in the brain, spleen, heart, lung, and kidney in which sigma receptors are present as well as in the skeletal muscle. In the blocking study with one of four sigma receptor ligands including haloperidol, (+)-pentazocine, SA4503, and (-)-pentazocine (in the order of their affinity for sigma 1 receptor subtype), SA4503 and haloperidol significantly reduced the brain uptake of [ 11 C]SA4503 to approximately 30% of the control, but the other two benzomorphans did not. A high specific uptake of [ 11 C]SA4503 by the brain was also confirmed by ex vivo autoradiography (ARG) and PET. Ex vivo ARG showed a higher uptake in the vestibular nucleus, temporal cortex, cingulate cortex, inferior colliculus, thalamus, and frontal cortex, and a moderate uptake in the parietal cortex and caudate putamen. Peripherally, the blocking effects of the four ligands depended on their affinity for sigma 1 receptors. No 11 C-labeled metabolite was detected in the brain 30 min postinjection, whereas approximately 20% of the radioactivity was found as 11 C-labeled metabolites in plasma. These results have demonstrated that the 11 C-labeled sigma 1 receptor ligand [ 11 C]SA4503 has a potential for mapping sigma 1 receptors in the central nervous system and peripheral organs

  10. Cyber security. Compliance to the new CSA 290.7 standard

    Energy Technology Data Exchange (ETDEWEB)

    Daley, M.; Doucet, R.; Echlin, M.; MacDonald, M.; Mihaylov, V.; Sijs, J.; Trask, D. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2015-12-15

    Since 2008, the Canadian Nuclear Safety Commission (CNSC), similar to regulators of other critical industries, has requested their licensees to implement cyber security programs and conduct self- assessments without the benefit of an industry specific cyber security standard that provides common metrics for coverage and effectiveness of their programs. However, for the nuclear industry, a new CSA standard 290.7 entitled 'Cyber security for nuclear power plants and small reactor facilities', released in December 2014, will have the CNSC looking to facility operators to be compliant to the new standard. This paper will discuss initiatives at Canadian Nuclear Laboratories to develop of a suite of tools, techniques, and best practices that can be used by the regulator and industry for assessing compliance and effectiveness of cyber security technology and implementations. (author)

  11. Characterization of human placental glycosaminoglycans and regional binding to VAR2CSA in malaria infected erythrocytes

    DEFF Research Database (Denmark)

    Beaudet, Julie M; Mansur, Leandra; Joo, Eun Ji

    2014-01-01

    Placental malaria is a serious problem in sub-Saharan Africa. Young women are particular susceptible to contracting this form of malaria during their first or second pregnancy despite previously acquired immunity from past infections. Placental malaria is caused by Plasmodium falciparum parasites...... expressing VAR2CSA on the erythrocyte surface. This protein adheres to a low-sulfated chondroitin sulfate-A found in placental tissue causing great harm to both mother and developing fetus. In rare cases, the localization of infected erythrocytes to the placenta can even result in the vertical transmission...... of malaria. In an effort to better understand this infection, chondroitin sulfate was isolated from the cotyledon part of the placenta, which should be accessible for parasite adhesion, as well as two non-accessible parts of the placenta to serve as controls. The placental chondroitin sulfate structures...

  12. CSA's robotic arm, the Space Station Remote Manipulator System, inside the SSPF

    Science.gov (United States)

    1999-01-01

    Workers in the Space Station Processing Facility raise a segment of the Canadian Space Agency's Space Station Remote Manipulator System (SSRMS) to move it to a workstand. CSA's first contribution to the International Space Station (ISS), the SSRMS is the primary means of transferring payloads between the orbiter payload bay and the ISS for assembly. The 56-foot-long robotic arm includes two 12-foot booms joined by a hinge. Seven joints on the arm allow highly flexible and precise movement. Latching End Effectors are mounted on each end of the arm for grappling. Video cameras mounted on the booms and end effectors will give astronauts maximum visibility for operations and maintenance tasks on the ISS. The SSRMS is at KSC to begin a campaign of prelaunch processing activities. It is scheduled to be launched aboard Space Shuttle Endeavour on mission STS-100, currently planned for July 2000.

  13. Testing the atmospheric dispersion model of CSA N288.1 with site-specific data

    CERN Document Server

    Chouhan, S L

    2001-01-01

    The atmospheric dispersion component of CSA Standard N288. 1, which provides guidelines for calculating derived release limits, has been tested. Long-term average concentrations of tritium in air were predicted using site-specific release rates and meteorological data and compared with measured concentrations at 43 monitoring sites at all CANDU stations in Canada. The predictions correlate well with the observations but were found to be conservative, overestimating by about 50% on average. The model overpredicted 84% of the time, with the highest prediction lying a factor of 5.5 above the corresponding observation. The model underpredicted the remaining 16% of the time, with the lowest prediction about one-half of the corresponding measurement. Possible explanations for this bias are discussed but no single reason appears capable of accounting for the discrepancy. Rather, the tendency to overprediction seems to result from the cumulative effects of a number of small conservatisms in the model. The model predi...

  14. Detailed description of the Ócsa Bird Ringing Station, Hungary

    Directory of Open Access Journals (Sweden)

    Csörgő Tibor

    2016-12-01

    Full Text Available The present paper acts as an introduction to a series that will describe the exploratory analyses of migration phenology and morphometrics of the most common passerine species at the Ócsa Bird Ringing Station. This station is situated in the Ócsa Landscape Protection Area that belongs to the Duna–Ipoly National Park, Hungary. The area is somewhat cooler and more humid than the surrounding agricultural fields and tree plantations, covered by a mosaic of diverse hygrophilous vegetation patches. Bird trapping is mostly based on Japanese mist-net lines crossing different plant communities. During the period of 1984–2015, a total of 422,862 birds were trapped and ringed here, while 202,739 local, 1,235 within country, and 443 foreign recaptures were also recorded. Each bird is characterized by the following data: location and time of capture, species, age, sex, scores of fat, pectoral muscle, wing tip abrasion, and moult, length of wing, 3rd primary, and tail, and body mass. After subjected to a rigorous quality check, digital data are deposited in the archive of the Hungarian Bird Ringing Centre, and the EURING data base. From time to time, other research projects also utilized the accessibility of wild birds captured here, thus collection of blood samples, ecto- and endoparasites was carried out at the station. The relatively long time span, large number of species and individuals, and the readily available environmental (weather, vegetation, etc. data makes the avian data collected here a suitable base for studies of various disciplines like capture methodology, habitat preferences, breeding, migration, and wintering, effects of weather and climate change, and epidemiology of viruses and parasites.

  15. Multiple var2csa-type PfEMP1 genes located at different chromosomal loci occur in many Plasmodium falciparum isolates

    DEFF Research Database (Denmark)

    Sander, Adam F; Salanti, Ali; Lavstsen, Thomas

    2009-01-01

    in the VAR2CSA protein, sequence variation in the DBL2X region of var2csa genes in 54 P.falciparum samples was analyzed. Chromosome mapping of var2csa loci was carried out and a quantitative PCR assay was developed to estimate the number of var2csa genes in P.falciparum isolates from the placenta of pregnant......BACKGROUND: The var2csa gene encodes a Plasmodium falciparum adhesion receptor which binds chondroitin sulfate A (CSA). This var gene is more conserved than other PfEMP1/var genes and is found in all P. falciparum isolates. In isolates 3D7, FCR3/It4 and HB3, var2csa is transcribed from a sub...... women and from the peripheral circulation of other malaria patients. Sequence analysis, gene mapping and copy number quantitation in P.falciparum isolates indicate that there are at least two loci and that both var2csa-like genes can be transcribed. All VAR2CSA DBL2X domains fall into one of two...

  16. Studies of the utilization of phosphorus and nitrogen fertilizers by 32P and 15N isotopes

    International Nuclear Information System (INIS)

    Dombovari, Janos; Kiss, A.S.

    1983-01-01

    The utilization of phosphorus and nitrogen fertilizers in crop enhancement was studied with different plants and soils, using 15 N nad 32 P labelling. 15 N was determined by mass spectrometry, 32 P by radiometry. For nitrogen fertilizers better results were achieved by sequential small doses than by single higher doses. The utilization of phosphorus fertilizer strongly depends, in addition to the plant species, on the quality of the soil, especially on its Ca and N contents. Low and high soil liming increased and decreased the utilization of phosphorus, respectively, while nitrogen fertilizers increased it in each case. Measurement of the isotopically exchangable phosphorus content of soils represents a new technique for the determination of the phosphorus uptake. (A.L.)

  17. Determination of δ15 N in urban effluents by vacuum ammoniac microdiffusion

    International Nuclear Information System (INIS)

    Mortatti, Jefferson; Bendassolli, Jose A.; Trivelin, Paulo C.O.; Valerio, Rosa A.; Bonassi, Jose A.

    2002-01-01

    Due to the fact of the steam-distillation method to be more labor-intensive and subject to the cross-contamination, the diffusion techniques have replaced the steam-distillation procedure as the method for chemical and isotopic determination of the N-inorganic species in soil extracts, natural waters and domestic sewage. The ammonia diffusion method developed for automated 15 N analysis using acidified disks generally requires a long diffusion period of 72 to 144 hours and even than recovery may be incomplete. A simple method was proposed introducing the diffusion technique under vacuum in a cell of 50 mL. The diffusion period was reduced to 8 hours and the recovery of the 15 N-ammonium sulphate (20o/oo) was 95 to 100%. (author)

  18. Aqua ammonia 15 N obtaining and application with vainness for sugar-cane fertilization

    International Nuclear Information System (INIS)

    Vitti, Andre Cesar; Trivellin, Paulo Cesar O.; Oliveira, Claudineia R. de; Bendassoli, Jose A.

    2000-01-01

    Nitrogen compounds marked with the isotope 15 N are continuously being used in agronomic studies and, when associated to the isotopic dilution technique, they constitute an important tool in clarifying the N cycle. At the Centro de Energia Nuclear na Agricultura (CENA/USP), it was obtained ( 15 NH 4 ) 2 SO 4 enhanced at 3,5% of 15 N atoms, by means of the ionic exchange chromatography technique, which made possible to produce aqua ammonia ( 15 NH 3 aq). Four repetitions were taken to the aqua ammonia production process to use the nitrogen compound in the field experiment. In each process 150g of ammonium sulfate enhanced at 3,5% of 15 N atoms was used, obtaining 31,0 ± 1,6 g of aqua ammonia on the average (80% yield), with the same enhancement. The incidence of isotopic dilution has not been observed during the procedure, what made the use of such methodology possible. After obtaining the aqua ammonia 15 N through this procedure, it was added to the vinasse (an equivalent to 50 m 3 ha -1 ) in doses that corresponded to 70 kg ha -1 of N-NH 3 aq. The mixture was applied to the sugar-cane straw on the soil's surface, aimed to the crop's fertilization. The compound's isotopic composition was analyzed by means of a spectrometer of masses ANCA-SL Europe Scientific, while the total-N volatilized, by the micro-Kjeldahl. Method. In accordance to the low NH 3 (6,4 ± 1,9 kg ha -1 ) volatilization results, it could be concluded that the application of vinasse and aqua ammonia mixture to the straw on the soil's surface was efficient, due to the vinasse's acid character, which allowed the NH 3 , in presence of the ion H + , to stay in the NH 4 + form in solution. (author)

  19. (1)H, (13)C and (15)N resonance assignments of human FK506 binding protein 25.

    Science.gov (United States)

    Prakash, Ajit; Shin, Joon; Yoon, Ho Sup

    2015-04-01

    Human FKBP25, a nuclear protein, is a member of FK506 binding protein family (FKBP) and binds to immunosuppressive drugs such as FK506 and rapamycin. Human FKBP25 interacts with several nuclear proteins and regulates nuclear events. To understand the molecular basis of such interactions, we have performed NMR studies. Here, we report (1)H, (15)N and (13)C resonance assignments of the full-length human FKBP25 protein.

  20. Foliar fertilization of sugarcane (Saccharum spp): absorption and translocation of 15-N-labeled urea

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.; Carvalho, J.G. de; Silva, A.Q. da; Primavesi, A.C.P.A.; Camacho, E.; Eimori, I.E.; Guilherme, M.R.

    1988-01-01

    The absorption and translocation of foliar applied nitrogen as urea solution to sugar cane plants was evaluated. An experiment using the isotope dilution technique with 15 N labeled urea was carried out in green house condition. Seedlings of sugarcane variety IAC 53-150 were planted in pots with 5KG of top soil''latossolo vermelho amarelo, fase arenosa'' (Haplustox). (M.A.C.) [pt

  1. Chemienzymatic synthesis of Uridine. Nucleotides labeled with [15N] and [13C

    DEFF Research Database (Denmark)

    Gilles, Anne-Marie; Cristea, Ioan; Palibroda, Nicolae

    1995-01-01

    +necessary for the oxidation of glucose 6-phosphate and 6-phosphogluconate was recycled by glutamate dehydrogenase and excess of ammonia and a-oxoglutarate. Despite the number and complexity of the enzymatic steps, the synthesis of [15N,13C]UTP is straightforward with an overall yield exceeding 60%. This method, extended...... and diversified to the synthesis of all natural ribonucleotides, is a more economical alternative for obtaining nucleic acids for structural analysis by heteronuclear NMR spectroscopy....

  2. δ15N in the turtle grass from the Mexican Caribbean

    Science.gov (United States)

    Talavera-Saenz, A.; Sanchez, A.; Ortiz-Hernandez, M.

    2013-05-01

    Nutrient inputs associated with population growth threaten the integrity of coastal ecosystems. To assess the rapid increase in tourism, we compared the δ15N from Thalassia testudinum collected at sites with different levels of tourism development and population to detect the N inputs of wastewater discharge (WD) along the coast of Quintana Roo. The contributions of nitrogen enriched in 15N are directly related to the increase of WD inputs in areas of high tourism development (Nichupte Lagoon in Cancun, >3 million tourists per year from 2007 to 2011 and 0.7 million of resident population) and decreased towards Bahia Akumal and Tulum (>3 million tourists per year from 2007 to 2011 and 0.15 million of resident population). The δ15N from T. testudinum was significantly lower at Mahahual and Puerto Morelos (about 0.4 million tourists per year in 2007 to 2011 and 0.25 million of resident population) than other the sites. In areas of the lowest development and with tourist activity restricted and small population, such as the Yum Balam Reserve and Sian Ka'an Biosphere Reserve, the δ15N values were in much higher enrichment that Mahahual and Puerto Morelos. Therefore is suggested that Mahahual and Puerto Morelos may be used for baseline isotopic monitoring, over environmental pressure on the reef lagoon ecosystem, where tourist activities and population are growing very slow rate. The anthropogenic N input has the potential to impact, both environmentally and economically, the seagrass meadows and the coral reefs along the coast of Quintana Roo and the Caribbean.

  3. A Study of15N/14N Isotopic Exchange over Cobalt Molybdenum Nitrides.

    Science.gov (United States)

    Hunter, Stuart M; Gregory, Duncan H; Hargreaves, Justin S J; Richard, Mélissandre; Duprez, Daniel; Bion, Nicolas

    2013-08-02

    The 14 N/ 15 N isotopic exchange pathways over Co 3 Mo 3 N, a material of interest as an ammonia synthesis catalyst and for the development of nitrogen transfer reactions, have been investigated. Both the homomolecular and heterolytic exchange processes have been studied, and it has been shown that lattice nitrogen species are exchangeable. The exchange behavior was found to be a strong function of pretreatment with ca. 25% of lattice N atoms being exchanged after 40 min at 600 °C after N 2 pretreatment at 700 °C compared to only 6% following similar Ar pretreatment. This observation, for which the potential contribution of adsorbed N species can be discounted, is significant in terms of the application of this material. In the case of the Co 6 Mo 6 N phase, regeneration to Co 3 Mo 3 N under 15 N 2 at 600 °C occurs concurrently with 14 N 15 N formation. These observations demonstrate the reactivity of nitrogen in the Co-Mo-N system to be a strong function of pretreatment and worthy of further consideration.

  4. Plot-size for 15N-fertilizer recovery studies by tanzania-grass

    International Nuclear Information System (INIS)

    Martha Junior, Geraldo Bueno; Trivelin, Paulo Cesar Ocheuze; Corsi, Moacyr

    2009-01-01

    The understanding of the N dynamics in pasture ecosystems can be improved by studies using the 15 N tracer technique. However, in these experiments it must be ensured that the lateral movement of the labeled fertilizer does not interfere with the results. In this study the plot-size requirements for 15 N-fertilizer recovery experiments with irrigated Panicum maximum cv. Tanzania was determined. Three grazing intensities (light, moderate and intensive grazing) in the winter, spring and summer seasons were considered. A 1 m 2 plot-size, with a grass tussock in the center, was adequate, irrespective of the grazing intensity or season of the year. Increasing the distance from the area fertilized with 15 N negatively affected the N derived from fertilizer (Npfm) recovered in herbage.The lowest decline in Npfm values were observed for moderate and light grazing intensities. This fact might be explained by the vigorous growth characteristics of these plants. Increasing the grazing intensity decreased the tussock mass and, the smaller the tussock mass, the greater was the dependence on fertilizer nitrogen. (author)

  5. Determination of N2 -fixation ability of legume trees using the 15N method

    International Nuclear Information System (INIS)

    Wemay, Johannis; Syaukat, Sriharti; Sisworo, Elsje L

    1998-01-01

    A sequence field experiment has been conducted for determining the capability of N 2 -fixation by several legume trees. The experiment was designed using a randomize design with 4 replicates. Each replicate was planted with 100 legume trees and 100 non legume trees. The isotope plot, where 15 N was applied with 18 legume trees and 18 non legume trees. The planting distance was 1m x 1m. For the calculation of N 2 -fixation each legume and standard tree (Eucalypthus alba) was applied with 12.52g in the from of ammonium sulfate with 10.12% 15 N. The 15 N AS was applied in three splits 11 month earlier. Data obtained from this experiment showed that percentage of N derived from fixation (%N-dfF) of all legume trees was reasonable high. The legume trees used in this experiment were, Leucaena leucocephala, Acacia mangium, Caliandra tetragona, Flemengia congesta and Gliriciadia sepium with potential fixation from 62.31% to 90,68%. (author)

  6. Behavior of 15N-labelled amino acids in germinated corn

    International Nuclear Information System (INIS)

    Samukawa, Kisaburo; Yamaguchi, Masuro

    1979-01-01

    By investigating the rise and fall of 15 N-labelled amino acids in germinated corns, the behavior of amino radicals in free amino acids, the influence of the hydrolysis products of stored proteins on free amino acids and the change from heterotrophy to autotrophy of seeds were clarified. The amount of amino acid production depending on external nitrogen was very small in the early period of germination. 15 N incorporation into proline was not observed in the early period of germination, which suggested that the proline may be nitrogen-storing source. Most of the amino-state nitrogen of asparagine accumulated at the time of germination was internal nitrogen, and this fact suggested that aspartic acid serve as the acceptor of ammonia produced in the early stage of germination. 15 N content increased significantly on 9 th day after germination, and decreased on 12 th day. These facts prove that there are always active decomposition and production of protein in plant body. (Kobatake, H.)

  7. Nitrogen processing in a tidal freshwater marsh: a whole ecosystem 15N labeling study

    DEFF Research Database (Denmark)

    Gribsholt, B.; Boschker, H.T.S.; Struyf, E.

    2005-01-01

    and retention were traced in six subsequent tide cycles. We present data for the water phase components of the marsh system, in which changes in concentration and isotopic enrichment of NO3-, NO2- , N2O, N2, NH4+, and suspended particulate nitrogen (SPN) were measured in concert with a mass balance study......We quantified the fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrient-rich Scheldt River in a whole-ecosystem 15N labeling experiment. 15N-NH4+ was added to the floodwater entering a 3,477 m2 tidal marsh area, and marsh ammonium processing......, with nitrification accounting for 30% of 15N-transformation. In situ whole-ecosystem nitrification rates were four to nine times higher than those in the water column alone, implying a crucial role for the large reactive marsh surface area in N-transformation. Under conditions of low oxygen concentrations and high...

  8. Recovery of 15N-labelled fertilizers applied to bromegrass on a thin black chernozem soil

    International Nuclear Information System (INIS)

    Malhi, S.S.

    1995-01-01

    The availability of N fertilizers on established grass stands is a function of such processes as immobilization, gaseous loss, leaching and position of applied N. A field experiment was conducted on a Thin Black Chernozem soil at Crossfield, Alberta to determine the effect of source, time and method of application on the recovery of 15 N-labelled fertilizers applied to smooth bromegrass (Bromus inermis Leyss.). The treatments included two sources of N [urea and ammonium nitrate (AN)], four application times (early autumn, late autumn, early spring and late spring) and two methods of placement (surface-broadcast and subsurface banding). In most cases the 15 N recovery in soil did not differ much between urea and AN. However, when urea was surface-broadcast, there was, on average, 10.2% less 15 N recovery in plants than AN. The N recovery for late spring > early spring > late autumn = early autumn. When urea was banded 4 cm deep into the soil, N recovery in plants increased significantly compared with its surface-broadcast application. However, this was not observed when the source of N was AN. Banding generally increased the amount of immobilized N present in the soil and N recovery. We concluded that the N recovery in plants and in plants plus soil was less for urea than for AN and was less with autumn broadcast N application than with spring broadcast application. (author). 23 refs., 3 tabs

  9. Historical δ15N records of Saccharina specimens from oligotrophic waters of Japan Sea (Hokkaido)

    Science.gov (United States)

    Kuribayashi, Takanori; Abe, Tsuyoshi; Montani, Shigeru

    2017-01-01

    Historically Saccharina spp. beds occurred along the west coast of Hokkaido, an oligotrophic area, and were commercially exploited. Currently extensive commercial Saccharina spp. beds do not form due to nutrient limitations. Here, we postulate that nutrients assimilated by paleo-Saccharina spp. beds may have been derived from spawning herrings (Clupea pallasii) acting as organisms that formed a vector from their feeding grounds (Okhotsk Sea and Pacific Ocean) to their spawning area (west coast of Hokkaido, Japan Sea). To test this hypothesis we examined stable nitrogen isotope ratios (δ15N) of 100– to 135–year-old Saccharina specimens preserved at the Herbarium (Hokkaido University Museum). δ15N values of the paleo-Saccharina specimens collected from this region were in the range of 10‰, which is significantly higher than the current 3–7‰ in freshly sampled Saccharina spp. This high δ15N indicates that spawning herring (Clupea pallasii) had potentially been a significant source of dissolved inorganic nitrogen (DIN) absorbed by Saccharina, acting as an organism forming a vector for transporting nutrients from eutrophic to oligotrophic coastal ecosystems. Our findings support the hypothesis of so-called “herring-derived nutrients.” PMID:28704453

  10. δ15N values of forage grasses and preliminary evaluation of their dinitrogen fixation potential for them

    International Nuclear Information System (INIS)

    Yao Yunyin; Chen Ming; Ma Changlin; Wang Zhidong; Hou Jingqin; Zhang Lihong; Luo Yongyun

    1992-01-01

    There exist different δ 15 N values in shoots of different species and varieties of leguminosae grasses, showing that the potentialities of their dinitrogen fixation were apparently different. The δ 15 N values in shoots of some grasses tested were too low, and very close to δ 15 N value of atmospheric N 2 (0%). It is possible that they get N to meet the needs of their growth through some associative dinitrogen fixation processes. Further study should be done

  11. Study of the giant dipole resonances of 16O and 15N by means of radiative captures

    International Nuclear Information System (INIS)

    Degre, Andre.

    1976-01-01

    The giant dipole resonance in 16 O and 15 N is studied with reactions 14 N(d,γ 0 ) 16 O, 13 C( 3 He,γ 0 ) 16 O and 11 B(α,γ 0 ) 15 N. The same energy range is observed with transfert reactions as 12 C( 7 Li,αγ) 15 N. A comparative study of radiative captures leading to 16 O and 15 N point out the importance of nsub(p)-nsub(t) configurations. Apparatus and experimental techniques developed are also described [fr

  12. Estimation of dinitrogen fixation by cowpea (Vigna unguiculata) using residual soil 15N in poppy (Papaver somniferum L) cowpea sequence

    International Nuclear Information System (INIS)

    Patra, D.D.; Chand, Sukhmal; Anwar, M.

    1994-01-01

    Estimation of dinitrogen fixation by cowpea was carried out under greenhouse conditions using pots each containing 12 kg soil. Different 15 N sources included residual soil 15 N where urea was applied to opium poppy before planting of cowpea as fixing and maize as non-fixing crop. Other N sources were labelled urea, 15 N labelled poppy straw, and labelled urea + unlabelled poppy straw. The amount of N 2 fixed varied with the source of 15 N in soil. Plant material treatment gave a higher estimate at 40 days, whereas the estimate was highest with residual 15 N at 75 days. Such variation is attributed to variation in 1 5N enrichment which can be reduced by utilizing the residual 15 N which gives a more stable enrichment of soil 15 N with time. It may also alleviate the errors resulting from the differential pattern of 15 N uptake by fixing and nonfixing plant due to temporal variation in 15 N enrichment in soil. (author). 8 refs., 3 tabs

  13. Redox-controlled backbone dynamics of human cytochrome c revealed by 15N NMR relaxation measurements

    International Nuclear Information System (INIS)

    Sakamoto, Koichi; Kamiya, Masakatsu; Uchida, Takeshi; Kawano, Keiichi; Ishimori, Koichiro

    2010-01-01

    Research highlights: → The dynamic parameters for the backbone dynamics in Cyt c were determined. → The backbone mobility of Cyt c is highly restricted due to the covalently bound heme. → The backbone mobility of Cyt c is more restricted upon the oxidation of the heme. → The redox-dependent dynamics are shown in the backbone of Cyt c. → The backbone dynamics of Cyt c would regulate the electron transfer from Cyt c. -- Abstract: Redox-controlled backbone dynamics in cytochrome c (Cyt c) were revealed by 2D 15 N NMR relaxation experiments. 15 N T 1 and T 2 values and 1 H- 15 N NOEs of uniformly 15 N-labeled reduced and oxidized Cyt c were measured, and the generalized order parameters (S 2 ), the effective correlation time for internal motion (τ e ), the 15 N exchange broadening contributions (R ex ) for each residue, and the overall correlation time (τ m ) were estimated by model-free dynamics formalism. These dynamic parameters clearly showed that the backbone dynamics of Cyt c are highly restricted due to the covalently bound heme that functions as the stable hydrophobic core. Upon oxidation of the heme iron in Cyt c, the average S 2 value was increased from 0.88 ± 0.01 to 0.92 ± 0.01, demonstrating that the mobility of the backbone is further restricted in the oxidized form. Such increases in the S 2 values were more prominent in the loop regions, including amino acid residues near the thioether bonds to the heme moiety and positively charged region around Lys87. Both of the regions are supposed to form the interaction site for cytochrome c oxidase (CcO) and the electron pathway from Cyt c to CcO. The redox-dependent mobility of the backbone in the interaction site for the electron transfer to CcO suggests an electron transfer mechanism regulated by the backbone dynamics in the Cyt c-CcO system.

  14. A novel method for trapping and analyzing 15N in NO for tracing NO sources

    Science.gov (United States)

    Kang, Ronghua; Mulder, Jan; Dörsch, Peter

    2016-04-01

    15N isotope tracing is an effective and direct approach to investigate the biological and chemical sources of nitric oxide (NO) in soil. However, NO is highly reactive and rapidly converted to nitrogen dioxide (NO2) in the presence of ozone. Various chemical conversions of NO to the more stable solutes nitrite (NO2-) and nitrate (NO3-) have been proposed, which allow analysing the 15N abundance without major fractionation. However, NO emissions from soils are usually small, posing major challenges to conversion efficiency and background contamination. Here we present a novel method in which NO is oxidized to NO2- by chromium trioxide (CrO3) prior to conversion to NO2- and NO3- in an alkaline hydrogen peroxide (H2O2) solution. Immediately following trapping, manganese dioxide (MnO2) and 5M HCl are added to remove excess H2O2, and to adjust the pH to around 6.0-7.0, respectively. The resulting solution can be stored until analysis and is none-toxic, allowing to use a modified denitrifier method (Zhu et al., submitted), where NO2- and NO3- are reduced quantitatively to nitrous oxide (N2O). Optimum NO conversion rates of > 90% even at extremely low initial NO concentration were obtained with 4% H2O2, 0.5 M NaOH, and 0.5 L min-1 gas flow rate. In a laboratory test, using NO gas with different 15N signals produced from unlabelled and labelled NO2-, we found an overall precision of 0.4‰ for unlabelled and 49.7‰ for NO enriched with 1.0 atom% 15N, respectively. This indicates that this method can be used for both natural abundance studies of NO, as well as in labelling studies tracing NO sources. Zhu J, Yu L, Bakken LR, Mørkved PT, Mulder J, Dörsch P. Controlled induction of denitrification in Pseudomonas aureofaciens: a modified denitrifier method for 15N and 18O analysis in NO3- from natural water samples by IRMS. Submitted.

  15. Multi-Informant Assessment of Anxiety regarding Ano-Genital Examinations for Suspected Child Sexual Abuse (CSA)

    Science.gov (United States)

    Scribano, Philip V.; Hornor, Gail; Rhoda, Dale; Curran, Sherry; Stevens, Jack

    2010-01-01

    Objective: Given the commonly held belief that physical examinations for child sexual abuse (CSA) are very distressing, our primary objective was to evaluate anxiety during these assessments using the Multidimensional Anxiety Score for Children (MASC-10). A second objective was to compare self-reported anxiety to parental report using the MASC-10…

  16. Human pregnancy-associated malaria-specific B cells target polymorphic, conformational epitopes in VAR2CSA

    DEFF Research Database (Denmark)

    Barfod, L.; Bernasconi, N. L.; Dahlback, M.

    2007-01-01

    -molecular-weight (> 200 kDa) proteins, while seven reacted with either the DBL3-X or the DBL5-epsilon domains of VAR2CSA expressed either as Baculovirus constructs or on the surface of transfected Jurkat cells. We used a panel of recombinant antigens representing DBL3-X domains from P. falciparum field isolates...

  17. Applying a CSA scale to the evaluation of spatial operation ability for use of a control-display device.

    Science.gov (United States)

    Chen, Chun-wei; Lee, Chang-franw; Chang, Chien-cheng

    2008-11-01

    The purpose of this study is to explore the feasibility of applying the CSA scale to measure the individual spatial operation ability of operators using a control-display device. Because competent operators may be able to reduce the possibility of serious accidents from the control room, it is important to be able to effectively measure the individual differences among operators. For this reason, we adopted a 2 (cognitive styles)x2 (control-display pairing patterns) split-plot design for our experiment. This paper examined the differences between the performances of participants with field-dependent (FD) cognitive styles and field-independent (FI) cognitive styles in control-display pairing tasks, and the correlation between CSA scores and performances. The results of the experiment indicated that the CSA scale is capable of distinguishing between employees in their capacity to operate control-display devices effectively. Therefore, it is suggested that together with other performance measurement criteria, the CSA scale should serve as a measurement criterion to help screen control room operators. This would reduce the occurrence of possible errors and help to improve control room safety.

  18. Identification and characterization of B-cell epitopes in the DBL4e domain of VAR2CSA

    DEFF Research Database (Denmark)

    Ditlev, Sisse B; Nielsen, Morten A; Resende, Mafalda

    2012-01-01

    capacity to inhibit parasite adhesion to CSA. This region was further characterized and together these results suggest that even though antibodies against the synthetic peptides which cover this region did not recognize native protein, the results using the mutant domain suggest that this linear epitope...

  19. Delta15N values of tropical savanna and monsoon forest species reflect root specialisations and soil nitrogen status.

    Science.gov (United States)

    Schmidt, S; Stewart, G R

    2003-03-01

    A large number of herbaceous and woody plants from tropical woodland, savanna, and monsoon forest were analysed to determine the impact of environmental factors (nutrient and water availability, fire) and biological factors (microbial associations, systematics) on plant delta(15)N values. Foliar delta(15)N values of herbaceous and woody species were not related to growth form or phenology, but a strong relationship existed between mycorrhizal status and plant delta(15)N. In woodland and savanna, woody species with ectomycorrhizal (ECM) associations and putative N(2)-fixing species with ECM/arbuscular (AM) associations had lowest foliar delta(15)N values (1.0-0.6 per thousand ), AM species had mostly intermediate delta(15)N values (average +0.6 per thousand ), while non-mycorrhizal Proteaceae had highest delta(15)N values (+2.9 to +4.1 per thousand ). Similar differences in foliar delta(15)N were observed between AM (average 0.1 and 0.2 per thousand ) and non-mycorrhizal (average +0.8 and +0.3 per thousand ) herbaceous species in woodland and savanna. Leguminous savanna species had significantly higher leaf N contents (1.8-2.5% N) than non-fixing species (0.9-1.2% N) indicating substantial N acquisition via N(2) fixation. Monsoon forest species had similar leaf N contents (average 2.4% N) and positive delta(15)N values (+0.9 to +2.4 per thousand ). Soil nitrification and plant NO(3)(-) use was substantially higher in monsoon forest than in woodland or savanna. In the studied communities, higher soil N content and nitrification rates were associated with more positive soil delta(15)N and plant delta(15)N. In support of this notion, Ficus, a high NO(3)(-) using taxa associated with NO(3)(-) rich sites in the savanna, had the highest delta(15)N values of all AM species in the savanna. delta(15)N of xylem sap was examined as a tool for studying plant delta(15)N relations. delta(15)N of xylem sap varied seasonally and between differently aged Acacia and other savanna

  20. The Influence of Seed-borne N in 15N Isotope Dilution Studies with Legumes The Influence of Seed-borne N in 15N Isotope Dilution Studies with Legumes

    DEFF Research Database (Denmark)

    Jensen, Erik Steen; Andersen, A. J.; Thomsen, J. D.

    1985-01-01

    The distriution of seed-borne N in shoot and root of pea and field bean was studied using three methods: 1) determination of the N content in shoot and root of plants grown in sand culture without other N sources. 2) 15N isotope dilution in plants grown in Rhizobium-free medium supplied with 15N...

  1. Murine Model for Preclinical Studies of Var2CSA-Mediated Pathology Associated with Malaria in Pregnancy

    Science.gov (United States)

    Dechavanne, Sebastien; Sousa, Patrícia M.; Barateiro, André; Cunha, Sónia F.; Nunes-Silva, Sofia; Lima, Flávia A.; Murillo, Oscar; Marinho, Claudio R. F.; Gangnard, Stephane; Srivastava, Anand; Braks, Joanna A.; Janse, Chris J.; Gamain, Benoit; Penha-Gonçalves, Carlos

    2016-01-01

    Plasmodium falciparum infection during pregnancy leads to abortions, stillbirth, low birth weight, and maternal mortality. Infected erythrocytes (IEs) accumulate in the placenta by adhering to chondroitin sulfate A (CSA) via var2CSA protein exposed on the P. falciparum IE membrane. Plasmodium berghei IE infection in pregnant BALB/c mice is a model for severe placental malaria (PM). Here, we describe a transgenic P. berghei parasite expressing the full-length var2CSA extracellular region (domains DBL1X to DBL6ε) fused to a P. berghei exported protein (EMAP1) and characterize a var2CSA-based mouse model of PM. BALB/c mice were infected at midgestation with different doses of P. berghei-var2CSA (P. berghei-VAR) or P. berghei wild-type IEs. Infection with 104 P. berghei-VAR IEs induced a higher incidence of stillbirth and lower fetal weight than P. berghei. At doses of 105 and 106 IEs, P. berghei-VAR-infected mice showed increased maternal mortality during pregnancy and fetal loss, respectively. Parasite loads in infected placentas were similar between parasite lines despite differences in maternal outcomes. Fetal weight loss normalized for parasitemia was higher in P. berghei-VAR-infected mice than in P. berghei-infected mice. In vitro assays showed that higher numbers of P. berghei-VAR IEs than P. berghei IEs adhered to placental tissue. Immunization of mice with P. berghei-VAR elicited IgG antibodies reactive to DBL1-6 recombinant protein, indicating that the topology of immunogenic epitopes is maintained between DBL1-6–EMAP1 on P. berghei-VAR and recombinant DBL1-6 (recDBL1-6). Our data suggested that impairments in pregnancy caused by P. berghei-VAR infection were attributable to var2CSA expression. This model provides a tool for preclinical evaluation of protection against PM induced by approaches that target var2CSA. PMID:27045035

  2. Quantifying protein dynamics in the ps–ns time regime by NMR relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, Griselda; LeMaster, David M., E-mail: david.lemaster@health.ny.gov [University at Albany - SUNY, Wadsworth Center, New York State Department of Health and Department of Biomedical Sciences, School of Public Health (United States)

    2016-11-15

    Both {sup 15}N chemical shift anisotropy (CSA) and sufficiently rapid exchange linebroadening transitions exhibit relaxation contributions that are proportional to the square of the magnetic field. Deconvoluting these contributions is further complicated by residue-dependent variations in protein amide {sup 15}N CSA values which have proven difficult to accurately measure. Exploiting recently reported improvements for the implementation of T{sub 1} and T{sub 1ρ} experiments, field strength-dependent studies have been carried out on the B3 domain of protein G (GB3) as well as on the immunophilin FKBP12 and a H87V variant of that protein in which the major conformational exchange linebroadening transition is suppressed. By applying a zero frequency spectral density rescaling analysis to the relaxation data collected at magnetic fields from 500 to 900 MHz {sup 1}H, differential residue-specific {sup 15}N CSA values have been obtained for GB3 which correlate with those derived from solid state and liquid crystalline NMR measurements to a level similar to the correlation among those previously reported studies. Application of this analysis protocol to FKBP12 demonstrated an efficient quantitation of both weak exchange linebroadening contributions and differential residue-specific {sup 15}N CSA values. Experimental access to such differential residue-specific {sup 15}N CSA values should significantly facilitate more accurate comparisons with molecular dynamics simulations of protein motion that occurs within the timeframe of global molecular tumbling.

  3. Effect of organic matter application on the fate of 15N-labeled ammonium fertilizer in an upland soil

    International Nuclear Information System (INIS)

    Nishio, T.; Oka, N.

    2003-01-01

    The effect of the application of organic matter on the fate of 15 N-labeled ammonium was investigated in a field. The organic materials incorporated into the experimental plots consisted of wheat straw, rape, pig compost, cow compost, plant manure. In May 2000, 10 g N m -2 of 15 N-labeled ammonium was applied to the field together with the organic materials, and maize and winter wheat were consecutively cultivated. The recovery of applied 15 N in soils and plants was determined after the harvest of each crop. Although only about 10% of the applied 15 N-labeled fertilizer remained in the 0-30 cm layer of the Control Plot and the Plant Manure Plot, more than 25% of the applied 15 N remained in the Pig Compost Plot. Amount and proportion of the immobilized 15 N to those of total N or microbial biomass N in soils were determined for the topsoil samples (0-10 cm layer). The amounts of both microbial biomass N and total immobilized 15 N in soil were highest in the Pig Compost Plot. Although the amount of microbial biomass N was comparable to the amount of immobilized 15 N-labeled fertilizer in soil, the amounts of 15 N-labeled fertilizer contained in the microbial biomass accounted for less than 10 % of the amount of total immobilized 15 N in soil. The ratio of the amount of 15 N-labeled fertilizer contained in biomass N to the total amount of biomass N was one order to magnitude higher than the ratio of the amount of immobilized 15 N-labeled fertilizer to the amount of total N in soil. No conspicuous changes in the amount of immobilized 15 N in soil were observed during the cultivation of winter wheat except for the Pig Compost Plot. No significant correlation was recognized between the amount of 15 N-labeled fertilizer contained in microbial biomass before wheat cultivation and that of 15 N-labeled fertilizer absorbed by wheat, indicating that microbial N immobilized during the growth period of the former crop (maize) was not a significant source of N for the latter

  4. Unusually negative nitrogen isotopic compositions (δ15N of mangroves and lichens in an oligotrophic, microbially-influenced ecosystem

    Directory of Open Access Journals (Sweden)

    I. Romero

    2008-12-01

    Full Text Available Extremes in δ15N values in mangrove tissues and lichens (range =+4 to −22‰ were measured from a mangrove forest ecosystem located on Twin Cays, offshore islands in Belize, Central America. The N isotopic compositions and concentrations of NH4+/NH3 in porewater, rainwater, and atmospheric ammonia, and the δ15N of lichens, mangrove leaves, roots, stems, and wood were examined to study the biogeochemical processes important for establishing these unusual N isotopic ratios. Dwarfed Rhizophora mangle trees had the most negative δ15N, whereas fringing Rhizophora trees, the most positive δ15N values. Porewater ammonium concentrations had little relationship to N isotopic fractionation in mangrove tissues. In dwarfed mangroves, the δ15N of fine and coarse roots were 6–9‰ more positive than leaf tissue from the same tree, indicating different sources of N for root and leaf tissues. When P was added to dwarfed mangrove trees without added N, δ15N increased within one year from −12‰ to −2‰, approaching the δ15N of porewater ammonium (δ15N=+4‰. Isotopically depleted ammonia in the atmosphere (δ15N=−19‰ and in rainwater (δ15N=−10‰ were found on Twin Cays. We propose that foliar uptake of these atmospheric sources by P-stressed, dwarfed mangrove trees and lichens can explain their very negative δ15N values. In environments where P is limiting for growth, uptake of atmospheric N by Rhizophora mangle may be an important adaptive strategy.

  5. Unusually negative nitrogen isotopic compositions (δ15N) of mangroves and lichens in an oligotrophic, microbially-influenced ecosystem

    Science.gov (United States)

    Fogel, M. L.; Wooller, M. J.; Cheeseman, J.; Smallwood, B. J.; Roberts, Q.; Romero, I.; Meyers, M. J.

    2008-12-01

    Extremes in δ15N values in mangrove tissues and lichens (range =+4 to -22‰) were measured from a mangrove forest ecosystem located on Twin Cays, offshore islands in Belize, Central America. The N isotopic compositions and concentrations of NH4+/NH3 in porewater, rainwater, and atmospheric ammonia, and the δ15N of lichens, mangrove leaves, roots, stems, and wood were examined to study the biogeochemical processes important for establishing these unusual N isotopic ratios. Dwarfed Rhizophora mangle trees had the most negative δ15N, whereas fringing Rhizophora trees, the most positive δ15N values. Porewater ammonium concentrations had little relationship to N isotopic fractionation in mangrove tissues. In dwarfed mangroves, the δ15N of fine and coarse roots were 6-9‰ more positive than leaf tissue from the same tree, indicating different sources of N for root and leaf tissues. When P was added to dwarfed mangrove trees without added N, δ15N increased within one year from -12‰ to -2‰, approaching the δ15N of porewater ammonium (δ15N=+4‰). Isotopically depleted ammonia in the atmosphere (δ15N=-19‰) and in rainwater (δ15N=-10‰) were found on Twin Cays. We propose that foliar uptake of these atmospheric sources by P-stressed, dwarfed mangrove trees and lichens can explain their very negative δ15N values. In environments where P is limiting for growth, uptake of atmospheric N by Rhizophora mangle may be an important adaptive strategy.

  6. A novel gingival overgrowth mouse model induced by the combination of CsA and ligature-induced inflammation.

    Science.gov (United States)

    Okanobu, Ai; Matsuda, Shinji; Kajiya, Mikihito; Fujita, Tsuyoshi; Kittaka, Mizuho; Shiba, Hideki; Kurihara, Hidemi

    2017-06-01

    Drug-induced gingival overgrowth (DIGO) is a side effect of the enlargement of gingival tissue by phenytoin, nifedipine, and cyclosporine A (CsA). Gingival inflammation has been identified as a key factor that initiates DIGO. However, a sufficient animal model for clarifying the role of inflammation in DIGO has not yet been generated. We herein describe a novel CsA-induced gingival overgrowth mouse model to evaluate the role of inflammation. A ligature was placed around the second molar in maxillae for 7days to induce gingival inflammation, and CsA (50mg/kg/day) was administered to mice during each experimental period. The severity of gingival overgrowth and mRNA expression of inflammatory cytokines in gingiva were assessed by the gingival overgrowth degree, histological analyses, and RT-PCR. The administration of CsA for 28days in combination with ligation significantly increased the gingival overgrowth degree and expanded the connective tissue area. Increases in the gingival overgrowth degree continued in a time-dependent manner until 21days. Furthermore, the cessation of CsA reduced gingival overgrowth. Thin ligatures (7-0 size) induced weaker tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 mRNA expression and less gingival overgrowth than thick ligatures (5-0 ligature). Moreover, the administration of an antibiotic cocktail, which suppressed the expression of these inflammatory cytokines in gingiva, attenuated gingival overgrowth induced by ligatures and CsA. These results suggest that inflammation in gingival tissue plays a role in initiating CsA-induced gingival overgrowth. This gingival overgrowth mouse model has potential for elucidating the etiology of DIGO from the view point of gingival inflammation. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Antibody levels to recombinant VAR2CSA domains vary with Plasmodium falciparum parasitaemia, gestational age, and gravidity, but do not predict pregnancy outcomes.

    Science.gov (United States)

    Fried, Michal; Kurtis, Jonathan D; Swihart, Bruce; Morrison, Robert; Pond-Tor, Sunthorn; Barry, Amadou; Sidibe, Youssoufa; Keita, Sekouba; Mahamar, Almahamoudou; Andemel, Naissem; Attaher, Oumar; Dembele, Adama B; Cisse, Kadidia B; Diarra, Bacary S; Kanoute, Moussa B; Narum, David L; Dicko, Alassane; Duffy, Patrick E

    2018-03-09

    Maternal malaria is a tropical scourge associated with poor pregnancy outcomes. Women become resistant to Plasmodium falciparum pregnancy malaria as they acquire antibodies to the variant surface antigen VAR2CSA, a leading vaccine candidate. Because malaria infection may increase VAR2CSA antibody levels and thereby confound analyses of immune protection, gravidity-dependent changes in antibody levels during and after infection, and the effect of VAR2CSA antibodies on pregnancy outcomes were evaluated. Pregnant women enrolled in a longitudinal cohort study of mother-infant pairs in Ouelessebougou, Mali provided plasma samples at enrollment, gestational week 30-32, and delivery. Antibody levels to VAR2CSA domains were measured using a multiplex bead-based assay. Antibody levels to VAR2CSA were higher in multigravidae than primigravidae. Malaria infection was associated with increased antibody levels to VAR2CSA domains. In primigravidae but not in secundigravidae or multigravidae, antibodies levels sharply declined after an infection. A relationship between any VAR2CSA antibody specificity and protection from adverse pregnancy outcomes was not detected. During malaria infection, primigravidae acquire short-lived antibodies. The lack of an association between VAR2CSA domain antibody reactivity and improved pregnancy outcomes suggests that the recombinant proteins may not present native epitopes targeted by protective antibodies.

  8. Localization of 15N uptake in a Tibetan alpine Kobresia pasture

    Science.gov (United States)

    Schleuß, Per-Marten; Kuzyakov, Yakov

    2014-05-01

    The Kobresia Pygmea ecotone covers approximately 450.000 km2 and is of large global and regional importance due several socio-ecological aspects. For instance Kobresia pastures store high amounts of carbon, nitrogen and other nutrients, represent large grazing areas for herbivores, provide a fast regrowth after grazing events and protect against mechanical degradation and soil erosion. However, Kobresia pastures are assumed to be a grazing induced and are accompanied with distinct root mats varying in thickness between 5-30 cm. Yet, less is known about the morphology and the functions of this root mats, especially in the background of a progressing degradation due to changes of climate and management. Thus we aimed to identify the importance of single soil layers for plant nutrition. Accordingly, nitrogen uptake from different soil depths and its remain in above-ground biomass (AGB), belowground biomass (BGB) and soil were determined by using a 15N pulse labeling approach during the vegetation period in summer 2012. 15N urea was injected into six different soil depths (0.5 cm, 2.5 cm, 7.5 cm, 12.5 cm, 17.5 cm, 22.5 cm / for each 4 replicates) and plots were sampled 45 days after the labeling. For soil and BGB samples were taken in strict sample intervals of 0-1 cm, 1-5 cm, 5-10 cm, 10-15 cm, 15-20 cm, 20-25 cm. Results indicate that total recovery (including AGB, BGB and soil) was highest, if tracer was injected into the top 5 cm and subsequently decreased with decreasing injection depth. This is especially the case for the 15N recovery of BGB, which is clearly attributed to the root density and strongly decreased with soil depth. In contrast, the root activity derived from the 15N content of roots increased with soil depth, which is primary associated to a proportionate increase of living roots related to dead roots. However, most 15N was captured in plant biomass (67.5-85.3 % of total recovery), indicating high 15N uptake efficiency possibly due to N limitation

  9. Nitrogen (15N) accumulation in corn grains as affected by source of nitrogen in red latosol

    International Nuclear Information System (INIS)

    Duete, Robson Rui Cotrim; Muraoka, Takashi; Trivelin, Paulo Cesar Ocheuze; Silva, Edson Cabral da; Ambrosano, Edmilson Jose

    2009-01-01

    Nitrogen is the most absorbed mineral nutrient by corn crop and most affects grains yield. It is the unique nutrient absorbed by plants as cation (NH 4 + ) or anion (NO 3 - ). The objectives of this work were to investigate the N accumulation by corn grains applied to the soil as NH 4 + or NO 3 - in the ammonium nitrate form compared to amidic form of the urea, labeled with 15 N; to determine the corn growth stage with highest fertilizer N utilization by the grains, and to quantify soil nitrogen exported by corn grains. The study was carried out in the Experimental Station of the Regional Pole of the Sao Paulo Northwestern Agribusiness Development (APTA), in Votuporanga, State of Sao Paulo, Brazil, in a Red Latosol. The experimental design was completely randomized blocks, with 13 treatments and four replications, disposed in factorial outline 6x2 + 1 (control, without N application). A nitrogen rate equivalent to 120 kg N ha-1 as urea- 15 N or as ammonium nitrate, labeled in the cation NH 4 + ( 15 NH 4 + NO 3 - ) or in the anion NO 3 - (NH 4 + 15N+O 3 - ), was applied in six fractions of 20 kg N ha-1 each, in different microplots, from seeding to the growth stage 7 (pasty grains). The forms of nitrogen, NH 4 + -N and N O 3 --N, were accumulated equitably by corn grains. The corn grains accumulated more N from urea than from ammonium nitrate. The N applied to corn crop at eight expanded leaves stage promoted largest accumulation of this nutrient in the grains. (author)

  10. Banding urea and lignosulfonate in corn (Zea mays L.) production and 15N recovery

    International Nuclear Information System (INIS)

    Alkanani, T.; MacKenzie, A.F.

    1996-01-01

    The use of urea in corn (Zea mays L.) production is common. Under current N fertilizer recommendations for corn, urea may have adverse effects on corn growth when applied in a band. The effects of ammonium lignosulfonate (LS) on corn growth and on N uptake from the banded application of urea and diammonium phosphate (DAP) mixtures were investigated on two soils from eastern Quebec. Field experiments were initiated in the first week of May 1991 on an Ormstown silty clay and a Ste. Rosalie clay soils (fine, mixed, nonacid, mesic Typic Humaquepts). Treatments were two rates of urea (30 and 90 kg urea-N ha -1 ) in a combination with DAP (14kg N ha 1 ), with or without banded fertilizer solutions of LS (8 kg N ha -1 ) applied at planting 5 cm to the side and 3 cm below the seed. A no treatment control was included. The low rate of urea compared with the unfertilized plots. When compared with the unfertilized treatment, the high rate of urea and DAP (no LS added) caused 10% increase in grain yield. However, addition of LS to the high rate of urea and DAP increase grain yield by band 20%. In general, LS significantly increased corn N uptake from urea on both soils. Separate 15 N field experiments were initiated in June 1991. Mean recovery of 15 N ranged from 17.8% to 30.9% of the applied labelled urea. The rate of urea-N banded had no significant effect on immobilization, but LS resulted in significantly less 15 N immobilized. These observations suggest that LS can reduce the biological immobilization of urea-N and increase the efficiency of urea fertilizer by reducing the negative effects of banding high levels of urea, while attaining benefits of band placement. (author). 29 refs., 6 tabs

  11. d15N dynamics of ammonium and particulate nitrogen during the growth season of a eutrophic estuary

    DEFF Research Database (Denmark)

    De Brabandere, Loreto; Brion, N.; Elskens, M.

    2007-01-01

    We monitored the stable nitrogen isotopic composition (d15N) of suspended matter and ammonium in the freshwater stretch of the Scheldt estuary (Belgium) over a full year to investigate for seasonal evolution and possible co-variation between isotopic signatures. The d15N value of ammonium remained...

  12. Determination of 15N nitrates in water samples using mass spectrometry

    International Nuclear Information System (INIS)

    Moya, P.; Aguirre, E.; Gallardo, P.

    2000-01-01

    The nitrogen element (Z = 7) has two stable isotopes, whose relative quantities are 99.64% for 14 N and 0.36% for 15 N. Nitrogen is part of many processes and reactions that are important to life and that affect the quality of the water. Within the nitrogen cycle there are kinetic and thermodynamic fractionation processes, which are potentially important for tracing its sources and demands. Water contamination due to nitrates is a serious problem that is affecting large parts of the biosphere. Surface water contamination can be remedied by prevention and control measures, but the problem becomes acute when the contamination penetrates to groundwater water. Contaminated groundwater can remain in the aquifers for centuries, even milleniums, and decontamination is very difficult, if not impossible. Isotopic techniques can help to evaluate how vulnerable the groundwater is to contamination from the surface when its displacement speed and extra load area are determined. Then the sources of surface contamination (natural, industrial, agricultural, domestic) can be identified. Isotopic techniques can also describe an incipient contamination, and they can provide an early alert when chemical or biological indicators do not reveal any signs for concern. The isotopic fractionation of several nitrogen compounds provide the basis for using 15 N as a hydrological isotope tool. There are three main sources of nitrogen contamination in water, these are: organic nitrogen in the soil, nitrogenized fertilizers, domestic, industrial and animal wastes. The following technical procedure describes the method for determining the isotopic ration 15 N/ 14 N in nitrates in water. The nitrate is separated from the water using ion exchange columns through a resin, which is eluded with HCI and with the addition of silver oxide becomes silver nitrate. This solution is freeze-dried and submitted to combustion at 850 in a sealed quartz tube, using copper/copper oxide for the nitrogen reduction

  13. Spin Resonance Clock Transition of the Endohedral Fullerene ^{15}N@C_{60}.

    Science.gov (United States)

    Harding, R T; Zhou, S; Zhou, J; Lindvall, T; Myers, W K; Ardavan, A; Briggs, G A D; Porfyrakis, K; Laird, E A

    2017-10-06

    The endohedral fullerene ^{15}N@C_{60} has narrow electron paramagnetic resonance lines which have been proposed as the basis for a condensed-matter portable atomic clock. We measure the low-frequency spectrum of this molecule, identifying and characterizing a clock transition at which the frequency becomes insensitive to magnetic field. We infer a linewidth at the clock field of 100 kHz. Using experimental data, we are able to place a bound on the clock's projected frequency stability. We discuss ways to improve the frequency stability to be competitive with existing miniature clocks.

  14. Effect of estrogens on urinary /sup 15/N balance in girls

    Energy Technology Data Exchange (ETDEWEB)

    Zachmann, M.; Kempken, B.; Prader, A. (Zurich Univ. (Switzerland))

    1984-08-01

    While the anabolic and growth-promoting effects of testosterone are known to be important for pubertal growth in boys, the role of estrogens (E) in the female spurt is less certain. Adrenal androgens have been considered to be more important than ovarian E. To study the anabolic effects of E, there has been carried out a pilot study in 9 girls aged 11 to 15 years. Before and 6 days after the start of E treatment, urinary /sup 15/N balance studies were performed, using /sup 15/NH/sub 4/Cl.

  15. Feasibility analysis of organic Tea authentication using 15N natural abundance method

    International Nuclear Information System (INIS)

    Feng Haiqiang; Pan Zhiqiang; Yu Cuiping; Wang Xiaochang

    2011-01-01

    Organic agricultural products were always adulterated by pollutant-free agricultural products in market because of lacking of available authentication technique. Organic tea was one of the largest organic agricultural products in China which are facing the same problem and can not be accepted by consumers. In this paper, based on the newest information of δ 15 N from soil-plant-fertilizer system, a new method was suggested to identify whether N fertilizer was applied to organic tea in producing processing. Meanwhile, the principle of this new method and its feasibility were discussed. (authors)

  16. Using 15N in studies on the uptake of mineral and organic nitrogen by plants

    International Nuclear Information System (INIS)

    Mitovska, R.

    1983-01-01

    Modelled microplot field experiments at the Central Experimental Station of the All-Union Institute of Fertilizers and Agrochemistry in Moscow were used to study the uptake of nitrogen ( 15 N) applied together or individually with minerals or with green oats mass or in both ways. The studies were conducted on soddy podzolic, heavy loam, soddy podzolic sandy soil and leached chernozem. It was established that the soddy podzolic heavy loam had the highest natural fertility and showed greatest response to the applied N

  17. Using /sup 15/N in studies on the uptake of mineral and organic nitrogen by plants

    Energy Technology Data Exchange (ETDEWEB)

    Mitovska, R. (Akademiya na Selskostopanskite Nauki, Sofia (Bulgaria). Inst. po Pochvoznanie)

    1983-01-01

    Modelled microplot field experiments at the Central Experimental Station of the All-Union Institute of Fertilizers and Agrochemistry in Moscow were used to study the uptake of nitrogen (/sup 15/N) applied together or individually with minerals or with green oats mass or in both ways. The studies were conducted on soddy podzolic, heavy loam, soddy podzolic sandy soil and leached chernozem. It was established that the soddy podzolic heavy loam had the highest natural fertility and showed greatest response to the applied N.

  18. Optical Microscopy Characterization for Borehole U-15n#12 in Support of NCNS Source Physics Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Jennifer E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sussman, Aviva Joy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-05-22

    Optical microscopy characterization of thin sections from corehole U-15n#12 is part of a larger material characterization effort for the Source Physics Experiment (SPE). The SPE program was conducted in Nevada with a series of explosive tests designed to study the generation and propagation of seismic waves inside Stock quartz monzonite. Optical microscopy analysis includes the following: 1) imaging of full thin sections (scans and mosaic maps); 2) high magnification imaging of petrographic texture (grain size, foliations, fractures, etc.); and 3) measurement of microfracture density.

  19. Macroalgae δ15N values in well-mixed estuaries: Indicator of anthropogenic nitrogen input or macroalgae metabolism?

    Science.gov (United States)

    Raimonet, Mélanie; Guillou, Gaël; Mornet, Françoise; Richard, Pierre

    2013-03-01

    Although nitrogen stable isotope ratio (δ15N) in macroalgae is widely used as a bioindicator of anthropogenic nitrogen inputs to the coastal zone, recent studies suggest the possible role of macroalgae metabolism in δ15N variability. Simultaneous determinations of δ15N of dissolved inorganic nitrogen (DIN) along the land-sea continuum, inter-species variability of δ15N and its sensitivity to environmental factors are necessary to confirm the efficiency of macroalgae δ15N in monitoring nitrogen origin in mixed-use watersheds. In this study, δ15N of annual and perennial macroalgae (Ulva sp., Enteromorpha sp., Fucus vesiculosus and Fucus serratus) are compared to δ15N-DIN along the Charente Estuary, after characterizing δ15N of the three main DIN sources (i.e. cultivated area, pasture, sewage treatment plant outlet). During late winter and spring, when human activities produce high DIN inputs, DIN sources exhibit distinct δ15N signals in nitrate (NO) and ammonium (NH): cultivated area (+6.5 ± 0.6‰ and +9.0 ± 11.0‰), pasture (+9.2 ± 1.8‰ and +12.4‰) and sewage treatment plant discharge (+16.9 ± 8.7‰ and +25.4 ± 5.9‰). While sources show distinct δN- in this multiple source catchment, the overall mixture of NO sources - generally >95% DIN - leads to low variations of δN-NO at the mouth of the estuary (+7.7 to +8.4‰). Even if estuarine δN-NO values are not significantly different from pristine continental and oceanic site (+7.3‰ and +7.4‰), macroalgae δ15N values are generally higher at the mouth of the estuary. This highlights high anthropogenic DIN inputs in the estuary, and enhanced contribution of 15N-depleted NH in oceanic waters. Although seasonal variations in δN-NO are low, the same temporal trends in macroalgae δ15N values at estuarine and oceanic sites, and inter-species differences in δ15N values, suggest that macroalgae δ15N values might be modified by the metabolic response of macroalgae to environmental parameters (e

  20. Life and death of a sewage treatment plant recorded in a coral skeleton δ15N record.

    Science.gov (United States)

    Duprey, Nicolas N; Wang, Xingchen T; Thompson, Philip D; Pleadwell, Jeffrey E; Raymundo, Laurie J; Kim, Kiho; Sigman, Daniel M; Baker, David M

    2017-07-15

    We investigated the potential of coral skeleton δ 15 N (CS-δ 15 N) records for tracking anthropogenic-N sources in coral reef ecosystems. We produced a 56yr-long CS-δ 15 N record (1958-2014) from a reef flat in Guam that has been exposed to varying 1) levels of sewage treatment 2) population density, and 3) land use. Increasing population density (from sewage treatment plant (STP) started operation in 1975. Then, CS-δ 15 N stabilized, despite continued population density and land use changes. Based on population and other considerations, a continued increase in the sewage footprint might have been expected over this time. The stability of CS-δ 15 N, either contradicts this expectation, or indicates that the impacts on the outer reef at the coring site were buffered by the mixing of reef water with the open ocean. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A 15N-poor isotopic composition for the solar system as shown by Genesis solar wind samples.

    Science.gov (United States)

    Marty, B; Chaussidon, M; Wiens, R C; Jurewicz, A J G; Burnett, D S

    2011-06-24

    The Genesis mission sampled solar wind ions to document the elemental and isotopic compositions of the Sun and, by inference, of the protosolar nebula. Nitrogen was a key target element because the extent and origin of its isotopic variations in solar system materials remain unknown. Isotopic analysis of a Genesis Solar Wind Concentrator target material shows that implanted solar wind nitrogen has a (15)N/(14)N ratio of 2.18 ± 0.02 × 10(-3) (that is, ≈40% poorer in (15)N relative to terrestrial atmosphere). The (15)N/(14)N ratio of the protosolar nebula was 2.27 ± 0.03 × 10(-3), which is the lowest (15)N/(14)N ratio known for solar system objects. This result demonstrates the extreme nitrogen isotopic heterogeneity of the nascent solar system and accounts for the (15)N-depleted components observed in solar system reservoirs.

  2. Synthesis of tetrazole-13C and 1,2,4-triazole-1,2-15N2

    International Nuclear Information System (INIS)

    Rowlett, R.S.; Klysa, Thomas; Shiraki, W.W.

    1990-01-01

    We report here the syntheses of tetrazole- 13 C and 1,2,4-triazole-1,2- 15 N 2 by simple, one-step procedures using common, commercially available, isotopically-labeled starting materials. Tetrazole- 13 C is conveniently prepared from K 13 CN and NaN 3 in 70% yield, almost twice the best reported yield for (unlabeled) tetrazole by similar synthetic methods. 1,2,4-triazole-1,2- 15 N 2 was synthesized in 35% yield from hydrazine- 15 N 2 sulphate and 1,3,5-triazine. From 15 N-NMR we determined that 15 N was specifically incorporated into the 1 and 2 positions of the triazole ring. (author)

  3. Testing the atmospheric dispersion model of CSA N288.1 with site-specific data

    International Nuclear Information System (INIS)

    Chouhan, S.L.; Davis, P.A.

    2001-01-01

    The atmospheric dispersion component of CSA Standard N288. 1, which provides guidelines for calculating derived release limits, has been tested. Long-term average concentrations of tritium in air were predicted using site-specific release rates and meteorological data and compared with measured concentrations at 43 monitoring sites at all CANDU stations in Canada. The predictions correlate well with the observations but were found to be conservative, overestimating by about 50% on average. The model overpredicted 84% of the time, with the highest prediction lying a factor of 5.5 above the corresponding observation. The model underpredicted the remaining 16% of the time, with the lowest prediction about one-half of the corresponding measurement. Possible explanations for this bias are discussed but no single reason appears capable of accounting for the discrepancy. Rather, the tendency to overprediction seems to result from the cumulative effects of a number of small conservatisms in the model. The model predictions were slightly better when site-specific meteorological data were used in the calculations in place of the default data of N288.1. Some large discrepancies between predictions and observations at specific monitoring sites suggest that it is the measurements rather than the model that are at fault. The testing has therefore provided a check on the observations as well as on the model. Recommendations on model use and data collection are made to improve the level of agreement between predictions and observations in the future. (author)

  4. Why so low? Making sense of 15N-depleted nitrogen isotope values in the Late Cretaceous.

    Science.gov (United States)

    Junium, C. K.; Meyers, S. R.; Arthur, M. A.

    2014-12-01

    Sedimentary organic matter from Cretaceous Oceanic Anoxic Events is characterized by universally low δ15N values. This observation has generated significant curiosity in the paleoceanographic community and has resulted in several conceptual models that aim to explain the 15N-depletion. The unifying element in these hypotheses is widespread anoxia and a series of nitrogen and/or metal cycling feedbacks. To address these hypotheses I will examine an interval in the middle Turonian (92.0 to 90.8 Ma) that demonstrates the impacts of redox and climate variability on nitrogen cycle dynamics. New N-isotope measurements from ODP Site 1259, Demerara Rise (DR) reveal δ15N values that range from +0.2‰ to -3.5‰ and oscillate by 1.5‰ to 3‰ over 1.6 Ma. A new astronomical time scale reveals a strong ~100 ka cyclicity in δ15N with little variance at ~400 ka through the mid-Turonian. The highest δ15N values and the largest amplitude ~100 ka cycles are found within the proposed glacial interval and cooler sea surface temperatures. The persistence of the ~100 ka δ15N cycle and δ15N maxima suggests a strong link between oceanic ventilation/circulation, climate, and the oscillations in δ15N are readily explained by variations in oxidation and expansion in the extent of denitrification within anoxic intermediate waters. These data confirm the strong link between water column redox variability and low δ15N values, but the exact mechanism of the 15N-depletion remains elusive.

  5. The efficiency of 32P, 15N foliage spray upon winter wheat

    International Nuclear Information System (INIS)

    Li Qiuzhi

    1985-01-01

    The efficiency of foliage spray of KH 2 PO 4 open wheat in heading stage is related to the content of effective P in the soil. In the irrigation field with high content of effective P and under the conditions of foliage spray of KH 2 PO 4 (3/1000), the wheat grain output was increased by 4.5-12.93% in comparison with control plot. It was increased by 7-16.07% in the soil with low content of effective P. By using 32 P-tracer determination it has been shown that the foliage spray of KH 2 PO 4 could increase the content of 32 P in the plant. The utilization coefficient of 32 P by plant was 19.8% while N and P were sprayed together the utilization coefficient was 28.6%, but the absolute value of absorbing capacity, however, only amounted to 0.65-0.91% of the total content of P in the plant observed. By using 15 N-tracing assay, it was found that the availability of 15 N-fertilizer to the roots of wheat after heading stage was rather high. The efficiency of foliage spray of N-fertilizer were not significant

  6. Nitrogen Dynamic Study on Rice Mutant Lines Using 15N Isotope Techniques

    International Nuclear Information System (INIS)

    Ahmad Nazrul Abd Wahid; Shyful Azizi Abdul Rahman; Abdul Rahim Harun

    2015-01-01

    Malaysian Nuclear Agency in collaboration with UPM and MARDI has produced two types of rice mutant lines of MR219, viz. MR219-4 and MR219-9 developed under rice radiation mutagenenesis programme for adaptability to aerobic conditions. Aerobic cultivating is rice cultivation system on well drained soil and using minimal water input. At Malaysian Nuclear Agency, a nitrogen fertilization study in aerobic condition for the rice mutant lines was carried out in the shade house and field. The study is intended to examine and assess the dynamics of nitrogen by rice mutant lines through the different soil water management and nitrogen levels. Direct 15 N isotopic tracer method was used in this study, whereby the 15 N labeled urea fertilizer was utilized as a tracer for nitrogen nutrient uptake by the test crops. This paper is intended to highlight the progress that has been made in the study of the nitrogen dynamics on MR219-4 and MR219-9 rice mutant lines. (author)

  7. Experimental assessment of the bioconcentration of (15)N-tamoxifen in Pseudokirchneriella subcapitata.

    Science.gov (United States)

    Orias, Frédéric; Simon, Laurent; Perrodin, Yves

    2015-03-01

    Nowadays, pharmaceutical compounds (PC) are ubiquitous in aquatic ecosystems. In addition to direct ecotoxicity, the bioconcentration of PC in organisms is a phenomenon which could have an impact on the whole ecosystem. In order to study this phenomenon, we exposed unicellular algae (Pseudokirchneriella subcapitata) to (15)N-tamoxifen, an anticancer drug labelled with a stable nitrogen isotope used as a tracer. By measuring (15)N enrichment over time, we were able to measure the increase of tamoxifen content in algae. This enrichment was measured by an elemental analyser coupled with an isotopic ratio mass spectrometer (EA-IRMS). Algal cells were exposed for 7d to 3 concentrations of tamoxifen: 1, 10 and 100μgL(-1). Our result shows a high bioconcentration in algae from the first minutes of contact. The highest bioconcentration factor measured is around 26500. We also observe that bioconcentration is not linked to the exposure concentration. This study is the first to use stable isotopes in order to monitor PCs in aquatic organisms such as algae. The use of stable isotopes in ecotoxicology offers interesting perspectives in the field of contaminant transfer in organisms and along the trophic web. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. 15 N- and 2 H proteomic stable isotope probing links nitrogen flow to archaeal heterotrophic activity

    Energy Technology Data Exchange (ETDEWEB)

    Justice, Nicholas B. [Univ. of California, Berkeley, CA (United States); Li, Zhou [Univ. of California, Berkeley, CA (United States); Wang, Yingfeng [Univ. of California, Berkeley, CA (United States); Spaulding, Susan E. [Univ. of California, Berkeley, CA (United States); Mosier, Annika C. [Univ. of California, Berkeley, CA (United States); Hettich, Robert L. [Univ. of California, Berkeley, CA (United States); Pan, Chongle [Univ. of California, Berkeley, CA (United States); Banfield, Jillian F. [Univ. of California, Berkeley, CA (United States)

    2014-05-20

    Understanding how individual species contribute to nutrient transformations in a microbial community is critical to prediction of overall ecosystem function. We conducted microcosm experiments in which floating acid mine drainage (AMD) microbial biofilms were submerged recapitulating the final stage in a natural biofilm life cycle. Biofilms were amended with either 15NH4 + or deuterium oxide (2H2O) and proteomic stable isotope probing (SIP) was used to track the extent to which different members of the community used these molecules in protein synthesis across anaerobic iron-reducing, aerobic iron-reducing and aerobic iron-oxidizing environments. Sulfobacillus spp. synthesized 15N-enriched protein almost exclusively under iron-reducing conditions whereas the Leptospirillum spp. synthesized 15N-enriched protein in all conditions. There were relatively few 15Nenriched archaeal proteins, and all showed low atom% enrichment, consistent with Archaea synthesizing protein using the predominantly 14N biomass derived from recycled biomolecules. In parallel experiments using 2H2O, extensive archaeal protein synthesis was detected in all conditions. In contrast, the bacterial species showed little protein synthesis using 2H2O. The nearly exclusive ability of Archaea to synthesize proteins using 2H2O may be due to archaeal heterotrophy, whereby Archaea off set deleterious effects of 2H by accessing 1H generated byrespiration of organic compounds.

  9. Biological nitrogen fixation in Crotalaria species estimated using the 15N isotope dilution method

    International Nuclear Information System (INIS)

    Samba, R.T.; Neyra, M.; Gueye, M.; Sylla, S.N.; Ndoye, I.; Dreyfus, B.

    2002-01-01

    Growing in Senegal by using 15 N direct isotope dilution technique. Two non-fixing plants, Senna obtusifolia and Senna occidentalis served as reference plants. The amount of nitrogen fixed two months after planting was obtained using the average of the two reference plants. The atom % 15 N excess in the Crotalaria species was significantly lower than that of the reference plants, indicating that significant nitrogen fixation occurred in the three plants. Significant differences were observed between the Crotalaria species; C. ochroleuca yielded more dry matter weight and total nitrogen than did C. perrottetti and C. retusa. The % nitrogen derived from atmosphere (%Ndfa) in leaves and stems was also higher in C. ochroleuca. There was no significant difference in %Ndfa in the whole plant between the three Crotalaria species (47% to 53%). In contrast, interspecific variability was observed based on the %Ndfa. C. ochroleuca significantly exhibited the higher amount of total nitrogen fixed, equivalent to 83 kg of nitrogen fixed per hectare. Based on these data, it was concluded that C. ochroleuca could be used in multiple cropping systems in Senegal for making more nitrogen available to other plants. (author)

  10. MUSIC in triple-resonance experiments: amino acid type-selective (1)H-(15)N correlations

    Science.gov (United States)

    Schubert; Smalla; Schmieder; Oschkinat

    1999-11-01

    Amino acid type-selective triple-resonance experiments can be of great help for the assignment of protein spectra, since they help to remove ambiguities in either manual or automated assignment procedures. Here, modified triple-resonance experiments that yield amino acid type-selective (1)H-(15)N correlations are presented. They are based on novel coherence transfer schemes, the MUSIC pulse sequence elements, that replace the initial INEPT transfer and are selective for XH(2) or XH(3) (X can be (15)N or (13)C). The desired amino acid type is thereby selected based on the topology of the side chain. Experiments for Gly (G-HSQC); Ala (A-HSQC); Thr, Val, Ile, and Ala (TAVI-HSQC); Thr and Ala (TA-HSQC), as well as Asn and Gln (N-HSQC and QN-HSQC), are described. The new experiments are recorded as two-dimensional experiments and therefore need only small amounts of spectrometer time. The performance of the experiments is demonstrated with the application to two protein domains. Copyright 1999 Academic Press.

  11. 15N isotopic techniques to study nitrogen cycle in soil-plant-atmosphere system

    International Nuclear Information System (INIS)

    Kumar, Manoj; Chandrakala, J.U.; Sachdev, M.S.; Sachdev, P.

    2009-01-01

    Intensification of agriculture to meet the increasing food demand has caused severe disruption in natural balance of global as well as regional nitrogen cycle, potentially threatening the future sustainability of agriculture and environment of the total fertilizer nitrogen used in agriculture globally, only less than half is recovered by crop plants, rest is lost to the environment, resulting in several environmental problems such as ground water pollution and global warming, besides huge economic loss of this costly input in agriculture. Improving fertilizer nitrogen use efficiency and minimising N loss to the environment is the key to regain the lost control of nitrogen cycle in agriculture. Fertilizer nitrogen use efficiency depends largely on N requirement of crops, N supply from soil and fertilizer through N transformations in soil, and N losses from the soil-water-plant system. 15 N isotopic techniques have the potential to provide accurate measurement quantification of different processes involved in N cycle such as fixation of atmospheric N 2 , transformations- mineralization and immobilization- of soil and fertilizer N which governs N supply to plants, and N losses to the environment through ammonia volatilization, denitrification and nitrate leaching. 15 N tracers can also give precise identification of ways and sources of N loss from agriculture. These information can be used to develop strategies for increasing fertilizer N use efficiency and minimizing the loss of this costly input from agriculture to environment, which in turn will help to achieve the tripartite goal of food security, agricultural profitability and environmental quality. (author)

  12. Use of Bio-Organic Fertilizers to Develop N Uptake Using 15N Technique

    International Nuclear Information System (INIS)

    Galal, Y.G.M.

    2008-01-01

    Experimental work either in field scale or in green house conditions were conducted using 15 N technique to evaluate the role of different bio fertilizers and different plant residues as organic amendments on enhancement of plant N nutrition. Nitrogen fixation by a symbiotic bacteria has been observed in greenhouse and field experiments under dry land cropping systems. Biological N 2 fixation associated with crop residues (legumes or cereals) was investigated in pot experiments with wheat and chickpea cultivars. In these experiments, labelled wheat and rice straw were used as organic N sources in comparison with either 15 N-labelled ammonium sulfate or ammonium nitrate as chemical nitrogen fertilizers. Rhizobium inoculation extended to be used with wheat gave the best results of N uptake and N 2 fixation when combined with Azospirillum brasilense as heterotrophic diazotrophs. The nitrogen uptake by wheat plants was significantly increased by application of soybean residues and inoculation with Azospirillum brasilense. From the field trial we can conclude that soybean residue as enriched N material, and Azospirillum brasilense inoculation enhanced N yields of wheat cultivars grown in poor fertile sandy soil

  13. Studies on nitrogen use efficiency in turmeric using 15N tagged urea

    International Nuclear Information System (INIS)

    Jagadeeswaran, R.; Arulmozhiselvan, K.; Govindaswamy, M.; Murugappan, V.

    2004-01-01

    A greenhouse experiment was conducted with turmeric in order to understand the partitioning of N between shoot and rhizome and to study the N use efficiency using 15 N tagged urea. The experiment was conducted in a completely randomized block design with seven treatments consisting of whole N application as basal and split applications ranging from two to six, besides a control. The result indicated that N derived from 15 N urea (Ndff) increased with number of split application of N up to four splits in turmeric shoot and up to three splits in turmeric rhizome, both at 180 days as well as at harvest stage. Increasing the splits beyond this declined Ndff, which indicated that five and more number of splits of N would not help to increase the uptake of applied N. Thus, the present study clearly revealed that in turmeric, application of N in three splits would be optimal in increasing the Ndff in rhizome. Fertilizer N balance calculations clearly indicated that the recovery of N in turmeric was high in favour of four splits at 180 days growth stage (19.46 per cent) as well as at harvest (30.76 per cent). (author)

  14. Growth, development, and fertilizer-15N recovery by the coffee plant

    International Nuclear Information System (INIS)

    Fenilli, Tatiele Anete Bergamo; Reichardt, Klaus; Bacchi, Osny Oliveira Santos; Dourado-Neto, Durval; Favarin, Jose Laercio; Trivelim, Paulo Cesar Ocheuze; Costa, Flavio Murilo Pereira da

    2007-01-01

    The relationship between growth and fertilizer nitrogen recovery by perennial crops such as coffee is poorly understood and improved understanding of such relations is important for the establishment of rational crop management practices. In order to characterize the growth of a typical coffee crop in Brazil and quantify the recovery of 15 N labeled ammonium sulfate, and improve information for fertilizer management practices this study presents results for two consecutive cropping years, fertilized with 280 and 350 kg ha -1 of N, respectively, applied in four splittings, using five replicates. Shoot dry matter accumulation was evaluated every 60 days, separating plants into branches, leaves and fruits. Labeled sub-plots were used to evaluate N-total and 15 N abundance by mass spectrometry. During the first year the aerial part reached a recovery of 71% of the fertilizer N applied up to February, but this value was reduced to 34% at harvest and 19% at the beginning of the next flowering period due to leaf fall and fruit export. For the second year the aerial part absorbed 36% of the fertilizer N up to March, 47% up to harvest and 19% up to the beginning of the next flowering period. The splitting into four applications of the used fertilizer rates was adequate for the requirements of the crop at these growth stages of the coffee crop. (author)

  15. Biosynthetic preparation of L-[13C]- and [15N]glutamate by Brevibacterium flavum

    International Nuclear Information System (INIS)

    Walker, T.E.; London, R.E.

    1987-01-01

    The biosynthesis of isotopically labeled L-glutamic acid by the microorganism Brevibacterium flavum was studied with a variety of carbon-13-enriched precursors. The purpose of this study was twofold: (i) to develop techniques for the efficient preparation of labeled L-glutamate with a variety of useful labeling patterns which can be used for other metabolic studies, and (ii) to better understand the metabolic events leading to label scrambling in these strains. B. flavum, which is used commercially for the production of monosodium glutamate, has the capability of utilizing glucose or acetate as a sole carbon source, and important criterion from the standpoint of developing labeling strategies. Unfortunately, singly labeled glucose precursors lead to excessive isotopic dilution which reduces their usefulness. Studies with [3- 13 C]pyruvate indicate that this problem can in principle be overcome by using labeled three-carbon precursors; however, conditions could not be found which would lead to an acceptable yield of isotopically labeled L-glutamate. In contrast, [1- 13 C]- or [2- 13 C]acetate provides relatively inexpensive, readily available precursors for the production of selectively labeled, high enriched L-glutamate. The preparation of L-[ 15 N]glutamate from [ 15 N]ammonium sulfate was carried out and is a very effective labeling strategy. Analysis of the isotopic distribution in labeled glutamate provides details about the metabolic pathways in these interesting organisms

  16. The effects of isotope-labeled analogs on the LC-IDMS measurement by comparison of ESI responses and matrix effect of melamine,13C3-melamine,13C3+15N3-melamine, and15N3-melamine.

    Science.gov (United States)

    Li, Xiu Qin; Zhang, Qing He; Yang, Zong; Li, Hong Mei; Huang, Dong Feng

    2017-05-01

    In this paper, the effect of isotope-labeled analogs on the liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) measurement was evaluated based on the comparison research of electrospray ionization responses (ESI) and matrix effect of melamine, 13 C 3 -melamine, 13 C 3 + 15 N 3 -melamine, and 15 N 3 -melamine. The isotope-labeled melamines had similar ionization efficiency with melamine in the electrospray ionization source, but the intensity of corresponding quantitative fragment ions had distinctive differences. Based on the density functional theory at the B3LYP/6-311+G** level, this phenomenon was explained very well. The rare cleavage pathways of melamine, which just could be exactly identified by 15 N-labeled melamines, resulted in the difference of quantitative fragment ions between 15 N-labeled melamines and melamine. The interaction of ESI response between melamine and isotope-labeled melamines was investigated using MRM monitor mode. 15 N-labeled melamine had significant ion inter-suppression effect on melamine, while 13 C-labeled melamine had little influence on melamine. Finally, the influence of different isotope-labeled melamines on the LC-IDMS result was evaluated using the IDMS correction factor (θ). Taking the determination of melamine in milk powder as an example, the matrix effects of different isotope-labeled melamines and melamine had notable difference and the impact of this difference on the measurement results depended on the concentrations of analyte and matrix solution. It was worth noting that 15 N 3 -melamine exhibited significant ion suppression to melamine in matrix solution. The deviation of the results from IDMS method might reach 59% using 15 N 3 -melamine as internal standard in special matrix solution. Graphical Abstract The comparison of ESI responses of melamine, 13 C 3 -melamine, 13 C 3 + 15 N 3 -melamine and 15 N 3 -melamine.

  17. Rapid, storm-induced changes in the natural abundance of sup 15 N in a planktonic ecosystem, Chesapeake Bay, USA

    Energy Technology Data Exchange (ETDEWEB)

    Montoya, J.P.; McCarthy, J.J. (Harvard Univ., Cambridge, MA (United States)); Horrigan, S.G. (State Univ. of New York, Stony Brook (United States))

    1991-12-01

    Samples of dissolved inorganic nitrogen (DIN), particulate nitrogen (PN), and two species of zooplankton were collected during two north-south transects of the Chesapeake Bay in the autumn of 1984 (27-28 September and 3-5 October). During the first transect, the natural abundance of {sup 15}N ({delta} {sup 15}N) in the major dissolved and planktonic pools of nitrogen suggested that the {delta}{sup 15}N of PN was largely determined by isotopic fractionation during uptake of NH{sub 4}{sup +} by phytoplankton. Averaged over the transect as a whole, the {delta}{sup 15}N of the herbivorous calanoid copepod Acartia tonsa was 4.1% higher than that of the PN, while the {delta}{sup 15}N of the carnivorous ctenophore Mnemiopsis leidyi was 6.4% higher than that of the PN. In the interval between the two transects, storm-induced mixing of the water column resulted in the injection of NH{sub 4}{sup +} into the surface layer of the bay. In combination with ancillary physical, chemical, and biological data, these changes in {delta}{sup 15}N provided estimates of the isotopic fractionation factor for NH{sub 4}{sup +} uptake by phytoplankton ({alpha} = 1.0065-1.0080) as well as the turnover time of nitrogen in Acartia tonsa (6.0-9.6 days). Despite the changes in {delta}{sup 15}N observed during this cruise, the relative distribution of {sup 15}N between trophic levels was preserved: during the second transect, the difference in {delta}{sup 15}N between Acartia tonsa and PN was 3.6%, and the difference in {delta}{sup 15}N between Mnemiopsis leidyi and PN was 7.3%. These results demonstrate that the natural abundance of {sup 15}N can change dramatically on a time scale of days, and that time-series studies of the natural abundance of {sup 15}N can be a useful complement to studies using tracer additions of {sup 15}N to document nitrogen transformations in planktonic ecosystems.

  18. Vegetation change alters soil profile δ15N values at the landscape scale in a subtropical savanna

    Science.gov (United States)

    Zhou, Y.; Mushinski, R. M.; Hyodo, A.; Wu, X. B.; Boutton, T. W.

    2017-12-01

    The assessment of spatial variation in soil δ15N could provide integrative insights on soil N cycling processes across multiple spatial scales. However, little is known about spatial patterns of δ15N within soil profiles in arid and semiarid ecosystems, especially those undergoing vegetation change with a distinct shift in dominance and/or functional type. We quantified how changes from grass to woody plant dominance altered spatial patterns of δ15N throughout a 1.2 m soil profile by collecting 320 spatially-specific soil cores in a 160 m × 100 m subtropical savanna landscape that has undergone encroachment by Prosopis glandulosa (an N2-fixer) during the past century. Leaf δ15N was comparable among different plant life-forms, while fine roots from woody species had significantly lower δ15N than herbaceous species across this landscape. Woody encroachment significantly decreased soil δ15N throughout the entire soil profile, and created horizontal spatial patterns of soil δ15N that strongly resembled the spatial distribution of woody patches and were evident within each depth increment. The lower soil δ15N values that characterized areas beneath woody canopies were mostly due to the encroaching woody species, especially the N2-fixer P. glandulosa, which delivered 15N-depleted organic matter via root turnover to soils along the profile. Soil δ15N increased with depth, reached maximum values at an intermediate depth, and decreased at greater depths. Higher δ15N values at intermediate soil depths were correlated with the presence of a subsurface clay-rich argillic horizon across this landscape which may favor more rapid rates of N-cycling processes that can cause N losses and 15N enrichment of the residual soil N. These results indicate that succession from grassland to woodland has altered spatial variation in soil δ15N across the landscape and to considerable depth, suggesting significant changes in the relative rates of N-inputs vs. N-losses in this

  19. Homogeneity of δ15N in needles of Masson pine (Pinus massoniana L.) was altered by air pollution

    International Nuclear Information System (INIS)

    Kuang Yuanwen; Wen Dazhi; Li Jiong; Sun Fangfang; Hou Enqing; Zhou Guoyi; Zhang Deqiang; Huang Longbin

    2010-01-01

    The present study investigated the changes of δ 15 N values in the tip, middle and base section (divided by the proportion to needle length) of current- and previous-year needles of Masson pine (Pinus massoniana L.) from two declining forest stands suffering from air pollution, in comparison with one healthy stand. At the healthy stand, δ 15 N in the three sections of both current- and previous-year needles were found evenly distributed, while at the polluted stands, δ 15 N values in the needles were revealed significantly different from the tip to the base sections. The results implied that the distribution of δ 15 N among different parts or sections in foliages was not always homogeneous and could be affected by air pollution. We suggested that the difference of δ 15 N values among pine needle sections should be reconsidered and should not be primarily ignored when the needle δ 15 N values were used to assess plant responses to air pollution. - Values of δ 15 N in needles of Masson pine (Pinus massoniana L.) were uneven and affected by air pollution.

  20. {sup 15}N-labeled nitrogen from green manure and ammonium sulfate utilization by the sugarcane ratoon

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosano, Edmilson Jose; Rossi, Fabricio, E-mail: ambrosano@apta.sp.gov.b [Agencia Paulista de Tecnologia dos Agronegocios (APTA), Piracicapa, SP (Brazil). Polo Rigional Centro Sul; Trivelin, Paulo Cesar Ocheuze [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis; Cantarella, Heitor [Agencia Paulista de Tecnologia dos Agronegocios (APTA/IAC), Campinas, SP (Brazil). Instituto Agronomico de Campinas. Centro de Solos e Recursos Agroambientais; Ambrosano, Glaucia Maria Bovi [Universidade de Campinas (UNICAMP/FOP), Piracicaba, SP (Brazil). Fac. de Odontologia de Piracicaba. Dept. de Odontologia Social, Bioestatistica; Schammass, Eliana Aparecida [Agencia Paulista de Tecnologia dos Agronegocios (APTA/IZ), Nova Odessa, SP (Brazil). Instituto de Zootecnia; Muraoka, Takashi [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Fertilidade do solo

    2011-05-15

    Legumes as green manure are alternative sources of nitrogen (N) for crops and can supplement or even replace mineral nitrogen fertilization due to their potential for biological nitrogen fixation (BNF). The utilization of nitrogen by sugarcane (Saccharum spp.) fertilized with sunn hemp (Crotalaria juncea L.) and ammonium sulfate (AS) was evaluated using the {sup 15}N tracer technique. N was added at the rate of 196 and 70 kg ha{sup -1} as {sup 15}N-labeled sunn hemp green manure (SH) and as ammonium sulfate (AS), respectively. Treatments were: (I) Control; (II) AS{sup 15}N; (III) SH{sup 15}N + AS; (IV) SH{sup 15}N; and (V) AS{sup 15}N + SH. Sugarcane was cultivated for five years and was harvested three times. {sup 15}N recovery was evaluated in the two first harvests. In the sum of the three harvests, the highest stalk yields were obtained with a combination of green manure and inorganic N fertilizer; however, in the second cutting the yields were higher where SH was used than in plots with AS. The recovery of N by the first two consecutive harvests accounted for 19 to 21% of the N applied as leguminous green manure and 46 to 49% of the N applied as AS. The amounts of inorganic N, derived from both N sources, present in the 0-0.4 m layer of soil in the first season after N application and were below 1 kg ha{sup -1}. (author)

  1. 7Li(15N,14C8Be reaction and 13,14C + 8Be nuclei interactions

    Directory of Open Access Journals (Sweden)

    А. Т. Rudchik

    2017-12-01

    Full Text Available Angular distributions of the 7Li(15N,14C8Be reaction were measured at the energy Elab(15N = 81 MeV. The reaction data were analyzed within coupled-reaction-channels (CRC method. The 7Li + 15N elastic and inelastic scattering and the more important one- and two-step transfers of this reaction were included in the channels-coupling scheme. Previously the 7Li + 15N optical potential parameters were deduced from the CRC analysis of the 7Li + 15N elastic scattering data at Elab(15N = 81 MeV. The spectroscopic amplitudes needed for CRC-calculations of the reaction were calculated within the translational invariant shell model (TISM. CRC analysis of the 7Li(15N,14C reaction data showed the p transfer dominants in this reaction. The parameters of the 14C + 8Be optical potential were deduced from CRC analysis of the reaction data and were compared with that of the 13C + 8Be potential parameters deduced previously from CRC analysis of 9Be(12C,13C8Be reaction data. The isotopic differences are observed.

  2. The degree of urbanization across the globe is not reflected in the δ(15)N of seagrass leaves.

    Science.gov (United States)

    Christiaen, Bart; Bernard, Rebecca J; Mortazavi, Behzad; Cebrian, Just; Ortmann, Alice C

    2014-06-30

    Many studies show that seagrass δ(15)N ratios increase with the amount of urbanization in coastal watersheds. However, there is little information on the relationship between urbanization and seagrass δ(15)N ratios on a global scale. We performed a meta-analysis on seagrass samples from 79 independent locations to test if seagrass δ(15)N ratios correlate with patterns of population density and fertilizer use within a radius of 10-200 km around the sample locations. Our results show that seagrass δ(15)N ratios are more influenced by intergeneric and latitudinal differences than the degree of urbanization or the amount of fertilizer used in nearby watersheds. The positive correlation between seagrass δ(15)N ratios and latitude hints at an underlying pattern in discrimination or a latitudinal gradient in the (15)N isotopic signature of nitrogen assimilated by the plants. The actual mechanisms responsible for the correlation between δ(15)N and latitude remain unknown. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Cereal grain, rachis and pulse seed amino acid δ15N values as indicators of plant nitrogen metabolism.

    Science.gov (United States)

    Styring, Amy K; Fraser, Rebecca A; Bogaard, Amy; Evershed, Richard P

    2014-01-01

    Natural abundance δ(15)N values of plant tissue amino acids (AAs) reflect the cycling of N into and within plants, providing an opportunity to better understand environmental and anthropogenic effects on plant metabolism. In this study, the AA δ(15)N values of barley (Hordeum vulgare) and bread wheat (Triticum aestivum) grains and rachis and broad bean (Vicia faba) and pea (Pisum sativum) seeds, grown at the experimental farm stations of Rothamsted, UK and Bad Lauchstädt, Germany, were determined by GC-C-IRMS. It was found that the δ(15)N values of cereal grain and rachis AAs could be largely attributed to metabolic pathways involved in their biosynthesis and catabolism. The relative (15)N-enrichment of phenylalanine can be attributed to its involvement in the phenylpropanoid pathway and glutamate has a δ(15)N value which is an average of the other AAs due to its central role in AA-N cycling. The relative AA δ(15)N values of broad bean and pea seeds were very different from one another, providing evidence for differences in the metabolic routing of AAs to the developing seeds in these leguminous plants. This study has shown that AA δ(15)N values relate to known AA biosynthetic pathways in plants and thus have the potential to aid understanding of how various external factors, such as source of assimilated N, influence metabolic cycling of N within plants. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. {delta}{sup 15}N of seagrass leaves for monitoring anthropogenic nutrient increases in coral reef ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Yamamuro, M.; Kayanne, H.; Yamano, H

    2003-04-01

    In a coral reef environment, a slight increase in dissolved inorganic nitrogen (DIN;{>=}1.0 {mu}M) can alter the ecosystem via macroalgal blooms. We collected seagrass leaves from the tropical and subtropical Pacific Ocean in five countries and examined the interactions between nutrient concentrations (C, N, P), molar ratios of nutrients, and {delta}{sup 15}N to find a possible indicator of the DIN conditions. Within most sites, the concentrations of nutrients and their molar ratios showed large variations owing to species-specific values. On the other hand, almost identical {delta}{sup 15}N values were found in seagrass leaves of several species at each site. The correlations between {delta}{sup 15}N and nutrient concentrations and between {delta}{sup 15}N and molar ratios of nutrients suggested that nutrient availability did not affect the {delta}{sup 15}N value of seagrass leaves by altering the physiological condition of the plants. Increases in {delta}{sup 15}N of seagrass leaves mostly matched increases in DIN concentrations in the bottom water. We suggest that {delta}{sup 15}N in seagrass leaves can be a good tool to monitor time-integrated decrease/increase of DIN concentrations at a site, both in the water column and the interstitial water.

  5. Studies of optical, morphological and electrical properties of POMA/PMMA blends, using two different levels of doping with CSA

    Directory of Open Access Journals (Sweden)

    Nizamara S. Pereira

    2012-01-01

    Full Text Available Poly(o-methoxyaniline (POMA was synthesized by oxidative polymerization of the monomer o-methoxyaniline. POMA/poly(methyl methacrylate (PMMA blends were produced by dissolving both polymers in chloroform (CHCl3.The amount of camphor sulfonic acid (CSA used as dopant of POMA was different, providing two methods for preparation of the blends. Solutions were analyzed by Fourier transform infrared spectroscopy (FTIR and then deposited on glass substrate by spin coating for characterization by atomic force microscope (AFM and current versus voltage (I × V curves. FTIR spectra of solutions were similar as expected. In the AFM images a reduction and/or loss of globules common in conducting polymers (CP such as polyaniline (PANI and its derivatives was observed. Films produced with different amounts of CSA presented distinct, linear and non-linear I × V curves.

  6. Methods of clinical chemistry and isotopic technique for investigation of the nitrogen metabolism in man using 15N

    International Nuclear Information System (INIS)

    Faust, H.; Bornhak, H.; Hirschberg, K.; Jung, K.; Junghans, P.; Krumbiegel, P.; Reinhardt, R.

    1981-03-01

    The present manual is a catalogue of methods representing theoretical and practical aspects of application of the stable isotope 15 N in medicine as well as a reference book for users of 15 N techniques in life sciences. Special emphasis is given to the planning of 15 N tracer experiments and their interpretation, sources of error and standard values of nitrogen compounds, information on sampling of medical materials, methods of separation and determination of proteins and non-protein nitrogen compounds in serum and urine, and details of the isotopic analysis of nitrogen by emission and mass spectrometry. (author)

  7. Multiyear fate of a15N tracer in a mixed deciduous forest: retention, redistribution, and differences by mycorrhizal association.

    Science.gov (United States)

    Goodale, Christine L

    2017-02-01

    The impact of atmospheric nitrogen deposition on forest ecosystems depends in large part on its fate. Past tracer studies show that litter and soils dominate the short-term fate of added 15 N, yet few have examined its longer term dynamics or differences among forest types. This study examined the fate of a 15 N-NO3- tracer over 5-6 years in a mixed deciduous stand that was evenly composed of trees with ectomycorrhizal and arbuscular mycorrhizal associations. The tracer was expected to slowly mineralize from its main initial fate in litter and surface soil, with some 15 N moving to trees, some to deeper soil, and some net losses. Recovery of added 15 N in trees and litterfall totaled 11.3% both 1 and 5-6 years after the tracer addition, as 15 N redistributed from fine and especially coarse roots into cumulative litterfall and small accumulations in woody tissues. Estimates of potential carbon sequestration from tree 15 N recovery amounted to 12-14 kg C per kg of N deposition. Tree 15 N acquisition occurred within the first year after the tracer addition, with no subsequent additional net transfer of 15 N from detrital to plant pools. In both years, ectomycorrhizal trees gained 50% more of the tracer than did trees with arbuscular mycorrhizae. Much of the 15 N recovered in wood occurred in tree rings formed prior to the 15 N addition, demonstrating the mobility of N in wood. Tracer recovery rapidly decreased over time in surface litter material and accumulated in both shallow and deep soil, perhaps through mixing by earthworms. Overall, results showed redistribution of tracer 15 N through trees and surface soils without any losses, as whole-ecosystem recovery remained constant between 1 and 5-6 years at 70% of the 15 N addition. These results demonstrate the persistent ecosystem retention of N deposition even as it redistributes, without additional plant uptake over this timescale. © 2016 John Wiley & Sons Ltd.

  8. Rapid mass spectrometric analysis of 15N-Leu incorporation fidelity during preparation of specifically labeled NMR samples

    DEFF Research Database (Denmark)

    Truhlar, Stephanie M E; Cervantes, Carla F; Torpey, Justin W

    2008-01-01

    . MALDI TOF-TOF MS/MS data provide additional information that shows where the "extra" (15)N labels are incorporated, which can be useful in confirming ambiguous assignments. The described procedure provides a rapid technique to monitor the fidelity of selective labeling that does not require a lot...... during protein expression is a common problem. We describe a rapid method to evaluate the fidelity of specific (15)N-amino acid incorporation. The selectively labeled protein is proteolyzed, and the resulting peptides are analyzed using MALDI mass spectrometry. The (15)N incorporation is determined...

  9. Transformation of 15N-labelled ammonium nitrate in a pot experiment with winter wheat

    International Nuclear Information System (INIS)

    Mueller, S.; Herbst, F.; Weigert, I.

    1986-01-01

    The transformation of 15 N-ammonium nitrate in the soil-plant system was investigated in Mitscherlich pots. Single nitrogen applications at the start of the growing season resulted in a decline in dry matter content and nitrogen uptake by the plant at the end of the ripening process. Root development shows respective reductions already after ear emergence. Nitrogen fertilization leads to an additional uptake of soil nitrogen. Between 60 and 85% of the fertilizer nitrogen is taken up by the plants. Only 2% of this nitrogen is found in the roots at the time of ripeness. Already 49 and 55 %, respectively, of the second nitrogen applications at the time of shooting or at the end of ear emergence is taken up by the plants after a few days, with 75 and 80%, respectively, of the nitrogen being utilized; but the second nitrogen application at the end of ear emergence has less influence on the crop yield. (author)

  10. A 115-year δ15N record of cumulative nitrogen pollution in California serpentine grasslands

    Science.gov (United States)

    Vallano, D.; Zavaleta, E. S.

    2010-12-01

    Until the 1980s, California’s biodiverse serpentine grasslands were threatened primarily by development and protected by reserve creation. However, nitrogen (N) fertilization due to increasing fossil fuel emissions in the expanding Bay Area is thought to be contributing to rapid, recent invasion of these ecosystems by exotic annual grasses that are displacing rare and endemic serpentine species. Documenting the cumulative effects of N deposition in this ecosystem can direct policy and management actions to mitigate the role of N deposition in its transformation. Natural abundance stable isotopes of N in vegetation have been increasingly used as bio-indicators of N deposition patterns and subsequent changes to plant N cycling and assimilation. However, the long-term record of atmospheric reactive N enrichment and the resulting changes in ecosystem N dynamics have yet to be adequately reconstructed in many ecosystems. Museum archives of vascular plant tissue are valuable sources of materials to reconstruct temporal and spatial isotopic patterns of N inputs to ecosystems. Here, we present N stable isotope data from archived and current specimens of an endemic California serpentine grassland species, leather oak (Quercus durata), since 1895 across the greater San Francisco Bay region. We measured spatial and temporal trends in stable isotope composition (δ15N and δ13C) and concentration (%N and %C) of historical and current samples of leather oak leaves from sites within the Bay Area, impacted by increasing development, and sites northeast of the Bay Area, with significantly lower rates of urbanization and industrialization. Specifically, we sampled dry museum and fresh leaf specimens from serpentine sites within Lake (n=27) and Santa Clara (n=30) counties dating from 1895 to 2010. Leaf δ15N values were stable from 1895 to the 1950s and then decreased strongly throughout the last 50 years as fossil fuel emissions rapidly increased in the Bay Area, indicating that

  11. The effects of 15N-fertilizer on the yields of wheat

    International Nuclear Information System (INIS)

    Zhou Dechao

    1985-01-01

    By using 15 N-fertilizer, the effects of increasing yield and the utilization of nitrogen of N-fertilizer applied at different periods and by different methods on wheat were studied. The results were as follows: The utilization of N-fertilizer by winter wheat is dependent on the fertilizer of soil before or after winter. Strong seedlings were obtained in the high fertility soils and the application of N-fertilizer in spring is recommended. In soils of low fertility, however, application of a part of N-fertilizer before winter is recommded in order to get strong seedlings. Application of a part of N-fertilizer as base manure for spring wheat is more advantageous. Deep application of N-fertilizer losses less NH 3 than surface broadcast does

  12. Fate of nitrogen fertilizers labelled with 15 N in two soil samples of Central Amazon, Brazil

    International Nuclear Information System (INIS)

    Alfaia, S.S.

    1997-01-01

    The efficiency of two nitrogen fertilizers, ammonium sulphate and urea, labelled with 15 N, in two major Central-Amazonian soils (Yellow Latosol an Oxisol and Red-Yellow Podzolic - an Ultisol), was studied in greenhouse experiments in Nancy, France, 1992. Italian rye-grass (Lolium multiflorum L.) was used as the test plant. Rye-grass nitrogen uptake of ammonium sulphate ranged from 44 tp 49%, and of urea from 60 to 70%. Immobilization and losses of nitrogen were dependent on the fertilizer type. Microbial nitrogen immobilization was higher in the presence of urea, while losses were higher with ammonium sulphate. Since losses of nitrogen fertilizers from leaching were practically nil under the experimental conditions, they might have occurred mainly through gaseous form. (author)

  13. Production of ammonium sulfate doubly labeled with the 15N and 34S stable isotopes

    International Nuclear Information System (INIS)

    Maximo, Everaldo; Bendassolli, Jose Albertino; Trivelin, Paulo Cesar Ocheuze; Rossete, Alexssandra Luiza Rodrigues Molina; Oliveira, Claudineia Raquel de; Prestes, Clelber Vieira

    2005-01-01

    The purpose of this work was the production of ammonium sulfate double labeled with 15 N and 34 S ((15NH 4 ) 2 34 SO 4 )), employing the ion exchange technique in two different processes. The first one was carried out using Na 2 34 SO 4 and ( 15 NH 4 ) 2 SO 4 previously enriched. It was possible to obtain about 54g of ( 15 NH 4 ) 2 34 SO 4 from 70.0g of Na 2 34 SO 4 and 64.2g of ( 15 NH 4 ) 2 SO 4 . The second method involved the production of H 2 34 SO 4 , by ion exchange, and its subsequent reaction with 15 NH 3(aq) , using a distillation system, to yield 58 g of ( 15 NH 4 ) 2 34 SO 4 from 43.1 g of H 2 34 SO 4 . (author)

  14. Study of surface layer on 08Kh15N5D2T steel

    International Nuclear Information System (INIS)

    Tyurin, A.G.; Povolotskij, V.D.; Zhivotovskij, Eh.A.; Berg, B.N.

    1986-01-01

    08Kh15N5D2T steel phase composition is investigated. Its surface layer was determined by X-ray diffraction analysis method. It is shown, that a subscale appears to be the reason for corrosion of products, made of EhP410 steel. Under the existing smelling technology the carbon content in it is ≥ 0.05%. Therefore to avoid the metal surface depletion with chromium, one must provide for titanium relation to carbon of not less than 4.5 and carry out the rolled product thermal treatment in a protective atmosphere; otherwise, the technology must include not only the removal of scale from steel but the metal subscale layer as well

  15. Determination of 15N/14N and 13C/12C in Solid and Aqueous Cyanides

    Science.gov (United States)

    Johnson, C.A.

    1996-01-01

    The stable isotopic compositions of nitrogen and carbon in cyanide compounds can be determined by combusting aliquots in sealed tubes to form N2 gas and CO2 gas and analyzing the gases by mass spectrometry. Free cyanide (CN-aq + HCNaq) in simple solutions can also be analyzed by first precipitating the cyanide as copper(II) ferrocyanide and then combusting the precipitate. Reproducibility is ??0.5??? or better for both ??15N and ??13C. If empirical corrections are made on the basis of carbon yields, the reproducibility of ??13C can be improved to ??0.2???. The analytical methods described herein are sufficiently accurate and precise to apply stable isotope techniques to problems of cyanide degradation in natural waters and industrial process solutions.

  16. Creating 13C- and 15N-enriched tree leaf litter for decomposition experiments

    Science.gov (United States)

    Szlavecz, K. A.; Pitz, S.; Chang, C.; Bernard, M.

    2013-12-01

    Labeling plant material with heavy isotopes of carbon and nitrogen can produce a traceable nutrient signal that can be followed into the different trophic levels and decomposer food web. We treated 60 tree saplings with 13C-enriched CO2 gas and 15N-enriched ammonium nitrate over a three-month period to create dually-labeled plant material for future decomposition experiments. The trees included both early (Red maple, Sweetgum, Tulip poplar) and late (American beech, White oak) successional deciduous tree species, and a conifer, White pine. We constructed a 2.4 m × 2.4 m × 2.4 m environmental chamber that was climate-controlled using an air conditioning system. An Arduino microcontroller interfaced with a Vaisala GMP343 CO2 probe maintained a CO2 concentration between 500-520 ppm by controlling a solenoid valve on the CO2 tank regulator. The trees were placed into the chamber in August 2012 and remained until senescence unless they were lost to death or disease. Ammonium nitrate was added twice, in September and October. Leaf samples were collected prior to the start of the experiment and after senescence, whereas root samples were collected only in December. Samples were dried, ground and analyzed using an isotope ratio mass spectrometer. American beech and White oak had 40% mortality, and 34% of tulip poplar trees were removed because of powdery mildew overgrowth or death. Most tulip poplar trees exhibited a second leaf out following senescence in late September. Nearly 1 kg of litter was produced with tulip poplar representing over half of the total mass. Levels of enrichment varied greatly by species. Beech (-14.2‰) and White oak (-4.8‰) had low levels of enrichment in comparison to early successional species such as Sweetgum (41.7‰) and Tulip poplar (30.7‰ [first leaf fall] and 238.0‰ [second leaf fall]). Leaf enrichment with 15N followed a similar pattern, though it was achieved at a higher level with δ15N values varying from 271.6‰ to 1354.2

  17. Isotopic ratios D/H and 15N/14N in giant planets

    Science.gov (United States)

    Marboeuf, Ulysse; Thiabaud, Amaury; Alibert, Yann; Benz, Willy

    2018-04-01

    The determination of isotopic ratios in planets is important since it allows us to investigate the origins and initial composition of materials. The present work aims to determine the possible range of values for isotopic ratios D/H and 15N/14N in giant planets. The main objective is to provide valuable theoretical assumptions on the isotopic composition of giant planets, their internal structure, and the main reservoirs of species. We use models of ice formation and planet formation that compute the composition of ices and gas accreted in the core and the envelope of planets. Assuming a single initial value for isotopic ratios in volatile species, and disruption of planetesimals in the envelope of gaseous planets, we obtain a wide variety of D/H and 15N/14N ratios in low-mass planets (≤100 Mearth) due to the migration pathway of planets, the accretion time of gas species whose relative abundance evolves with time, and isotope exchanges among species. If giant planets with mass greater than 100 Mearth have solar isotopic ratios such as Jupiter and Saturn due to their higher envelope mass, Neptune-type planets present values ranging between one and three times the solar value. It seems therefore difficult to use isotopic ratios in the envelope of these planets to get information about their formation in the disc. For giant planets, the ratios allow us to constrain the mass fraction of volatile species in the envelope needed to reproduce the observational data by assuming initial values for isotopic ratios in volatile species.

  18. δ15N constraints on long-term nitrogen balances in temperate forests

    Science.gov (United States)

    Perakis, S.S.; Sinkhorn, E.R.; Compton, J.E.

    2011-01-01

    Biogeochemical theory emphasizes nitrogen (N) limitation and the many factors that can restrict N accumulation in temperate forests, yet lacks a working model of conditions that can promote naturally high N accumulation. We used a dynamic simulation model of ecosystem N and δ15N to evaluate which combination of N input and loss pathways could produce a range of high ecosystem N contents characteristic of forests in the Oregon Coast Range. Total ecosystem N at nine study sites ranged from 8,788 to 22,667 kg ha−1 and carbon (C) ranged from 188 to 460 Mg ha−1, with highest values near the coast. Ecosystem δ15N displayed a curvilinear relationship with ecosystem N content, and largely reflected mineral soil, which accounted for 96–98% of total ecosystem N. Model simulations of ecosystem N balances parameterized with field rates of N leaching required long-term average N inputs that exceed atmospheric deposition and asymbiotic and epiphytic N2-fixation, and that were consistent with cycles of post-fire N2-fixation by early-successional red alder. Soil water δ15NO3 − patterns suggested a shift in relative N losses from denitrification to nitrate leaching as N accumulated, and simulations identified nitrate leaching as the primary N loss pathway that constrains maximum N accumulation. Whereas current theory emphasizes constraints on biological N2-fixation and disturbance-mediated N losses as factors that limit N accumulation in temperate forests, our results suggest that wildfire can foster substantial long-term N accumulation in ecosystems that are colonized by symbiotic N2-fixing vegetation.

  19. Evaluation of nitrogen sources in two barley varieties using the isotopic dilution method (15N)

    International Nuclear Information System (INIS)

    Nario, M.A; Pino, I; A; Albornoz G, M.P; Peyrelongue C, A

    2000-01-01

    Two barley varieties (Leo and Granifen) were sown under field conditions in two different soils (Vilcun and Collipulli series) in the south of Chile, to evaluate each genotype behaviour after applying four nitrogenous fertilizers: Urea (U), Sodium Chilean Nitrate (SS), Ammonium Nitrate (AN), and Ammonium Sulfate (AS), at a rate of 70 kg N ha 1 in the Vilcun serie and 90 kg N ha 1 in the Collipulli serie. The 15 N isotopic dilution method was used, labelling the soil with 20 kg N ha 1 AS enriched with 10% at. exc. 15 N as a standard fertilizer. The statistical design was that of completely randomized blocks with five treatments and four replicates. Plants were harvested when physiologically mature, dried, and ground into three fractions (leaves + stem, grains, and chaff) to measure the agronomic (dry matter yield and total N), and isotopic parameters (nitrogen derived from fertilizer, nitrogen derived from soil, fertilizer use efficiency, and A value). The grain Ndffu (kg ha 1 ) was higher in Leo's variety than in Granifen, mainly using the SS fertilizer. The same behaviour showed the Fertilizer Use Efficiency (FUE, %) parameter. On the other hand, Granifen showed the greatest Nddfu (kg ha 1 ) using SS in Collipulli's serie than in Vilcun. However, in Collipulli's serie, Granifen showed lowest percentage using AS as source. Regarding the nitrogen source equivalence, considering SS as a reference, it is observed that in Leo's variety it is possible to apply any fertilizer to reach the same result. For Granifen, serie Vilcun, with SS as a reference, it is necessary to have between 1,4 and 1,6 kg of the other sources in order to get the same result. For the same variety and the same fertilizer reference, in the serie Collipulli, 2,5 kg of AS are required to reach the same result

  20. Nitrogen acquisition, transport and metabolism in intact ectomycorrhizal associations studied by 15N stable isotope techniques

    International Nuclear Information System (INIS)

    Ek, H.

    1993-05-01

    The focus of this thesis is on the external mycelium and its role in nitrogen uptake, assimilation and translocation. Tree seedlings in association with ectomycorrhizal fungi were grown in observation chambers. The fungal mycelium were fed with 15-N ammonium or 15-N nitrate or a combination of both. The effects of Collembola on the ectomycorrhizal symbiosis were also studied. The results demonstrates an important role of the external mycelium of Paxillus involutus not only in the uptake but also in the assimilation of ammonium into a variety of different amino acids, primarily glutamine but also glutamic acid, aspartic acid, and alanine, immediately after uptake. The results indicate that ammonium is assimilated by GS and GOGAT or GDH in the mycelium at the uptake site. When nitrate was added to the mycelium as the sole nitrogen source nitrate was reduced in the mycelium and the product assimilated into amino acids. When ammonium nitrate was supplied to the fungal mycelium nitrate was taken up the fungus and transferred to the plant, however, apparently no assimilation of nitrate occurred in the external mycelium. Ammonium or an assimilation product, such as glutamine, probably represses nitrate reductase (NR) but not nitrate uptake and transfer in P. involutus. P. involutus nitrogen uptake and transfer to the associated mycorrhizal pine was up to 76% higher when low numbers of the Collembola Onychiurus armatus were present compared to when they were completely absent. This was probably an indirect effect as P. involutus hyphal growth rate and extramatrical biomass increased at a low Collembola density. At high Collembola densities P. involutus hyphal growth rate was retarded. (74 refs.)

  1. Antibody responses to the full-length VAR2CSA and its DBL domains in Cameroonian children and teenagers

    DEFF Research Database (Denmark)

    Fodjo, Barriere A Y; Atemnkeng, Njika; Esemu, Livo

    2016-01-01

    villages and 160 children with severe malaria from the city.  Results: Low Ab levels to VAR2CSA were detected in children; however, Ab levels to FV2 in teenagers were rare. Children preferentially recognized DBL2 (56-70%) and DBL4 (50-60%), while multigravidae produced high levels of IgG to DBL3, DBL5...... and FV2. Sixty-seven percent of teenage girls (n = 16/24) recognized ID1-ID2a region of VAR2CSA. Children with severe forms of malaria had significantly higher IgG to merozoite antigens (all p 0.05) when compared to the healthy children.  Conclusion: The study...... suggests that children, including teenage girls acquire Ab to VAR2CSA domains and FV2, but Ab levels are much lower than those needed to protect women from placental infections and repertoire of Ab responses to DBL domains is different from those in pregnant women. Interestingly, children with severe...

  2. Effects of climate on deer bone δ15N and δ13C: Lack of precipitation effects on δ15N for animals consuming low amounts of C 4 plants

    Science.gov (United States)

    Cormie, A. B.; Schwarcz, H. P.

    1996-11-01

    We have examined the relationship of bone collagen δ15N and δ13C to climatic variables, humidity, temperature, and amount of precipitation using fifty-nine specimens of North American white-tailed deer ( Odocoileus virginianus) from forty-six different locations. In previous studies of African mammals there was a significant correlation between bone collagen δ15N and local amount of precipitation. Results presented here similarly show an increase in δ15N with decreasing amount of precipitation but only for 25% of the animals, namely those consuming more than 10% C 4 plants. These animals also exhibited a significant correlation between δ13C and temperature which mirrors previous observations for grasses suggesting that these deer consume grasses during times of population and nutrient stress. In contrast, even in dry areas containing high proportions of C 4 grasses, the majority of the deer had consumed low amounts of C 4 plants and these deer did not have δ15N which correlate with amount of precipitation. Only when deer deviated from their normal feeding pattern by consuming C 4 plants or grasses did their δ15N correlate with amount of rainfall. For these animals, consumption of C 4 plants or grasses may signal conditions of water and nutrient stress. An increase in δ15N of bone collagen may result from combined effects from excretion of concentrated urine (to conserve water) and increased internal recycling of nitrogen (to conserve nitrogen).

  3. A suite of Mathematica notebooks for the analysis of protein main chain 15N NMR relaxation data

    International Nuclear Information System (INIS)

    Spyracopoulos, Leo

    2006-01-01

    A suite of Mathematica notebooks has been designed to ease the analysis of protein main chain 15 N NMR relaxation data collected at a single magnetic field strength. Individual notebooks were developed to perform the following tasks: nonlinear fitting of 15 N-T 1 and -T 2 relaxation decays to a two parameter exponential decay, calculation of the principal components of the inertia tensor from protein structural coordinates, nonlinear optimization of the principal components and orientation of the axially symmetric rotational diffusion tensor, model-free analysis of 15 N-T 1 , -T 2 , and { 1 H}- 15 N NOE data, and reduced spectral density analysis of the relaxation data. The principle features of the notebooks include use of a minimal number of input files, integrated notebook data management, ease of use, cross-platform compatibility, automatic visualization of results and generation of high-quality graphics, and output of analyses in text format

  4. Espectro infrarrojo de [zn(mh34](re042 com substituicion isotópica 14n/15n

    Directory of Open Access Journals (Sweden)

    Claudio Téllez

    1983-11-01

    Full Text Available The infrared spectra of [Zn(15NH34] (Re042 and the isotopoc shift 14N/15N (Zn-n for the metal-ligand band, is reportedInforma-se o espectro infravermelho do complexo de Zn(II, [Zn(15NH341(Re04 e o deslocamento isotópico 14N/15N, para a banda metal - ligante v(Zn-N.

  5. 15N nuclear reaction analysis for hydrogen profiling at TIT 4.75 MV Van de Graaff

    International Nuclear Information System (INIS)

    Suginaka, H.; Kawasaki, K.; Nakajima, M.; Ogawa, M.

    1992-01-01

    A 15 N beam line has been upgraded by installing a new analyzing magnet and by controlling beam parameters with a computer. An improved beam intensity of ∼ 20 pnA has realized a detection sensitivity of 10 20 H · cm -3 in the hydrogen profilling. The hydrogen profiles have been measured by the 15 N nuclear reaction for TiHx and TiHx-Au samples. These profiles are compared with the profiles obtained by SIMS. (author)

  6. Production of granules of urea, urea-ammonium sulphate and urea-potassium chloride enriched with 15N

    International Nuclear Information System (INIS)

    Bendassolli, J.A.

    1991-01-01

    Using a pearling tower it was possible to produce granulated urea, and granulated mixtures of ammonium sulphate and urea, potassium chloride and urea, Labelled in 15 N. Granulated urea with 1, 2, 3 and 4 mm of diameter was obtained using a system with a heating controller. A low concentration of biuret was observed in the granules produced ( 15 N-Labelled ( 15 NH 4' 15 NH 2 ) with variable proportion of ammonium sulphate and urea. (author)

  7. 15N and 13C abundances in marine environments with emphasis on biogeochemical structure of food networks

    International Nuclear Information System (INIS)

    Wada, E.

    1987-01-01

    Distributions of δ 15 N and δ 13 C for biogenic substances in the Antarctic Ocean and in the Otsuchi River estuary in Japan were investigated to construct isotope biogeochemical framework for assessing marine ecosystems. The isotopic compositions of phytoplankton were particularly low in the Antarctic Ocean. High nitrate and CO 2 concentrations in the surface sea waters, and the low light intensity seem to enhance the kinetic isotope fractionations that preferred the depletion of 15 N and 13 C in the algal body. A clear-cut linear relationship between animal δ 15 N and its trophic level was obtained in the Antarctic system. In the estuary, the variation of isotope ratios were principally governed by the mixing of land-derived organic matter, marine phytoplankton, and seagrasses. A food-chain effect of 15 N enrichment was also confirmed. An isotopically ordered structure was presented for a marine estuarine ecosystem. The isotopic abundances in a food network vary mainly because of the variation in 15 N and 13 C contents of primary producers grown under different environmental conditions and because of the enrichment of 15 N along food chains. (author)

  8. Cyanobacteria-derived nitrogen uptake by benthic invertebrates in Lake Taihu: a mesocosm study using 15N labeling

    Directory of Open Access Journals (Sweden)

    Yu J.

    2014-01-01

    Full Text Available Eutrophication of lakes can lead to dominance by cyanobacteria, which are hardly used by zooplankton due to their low nutrition value. However, sedimented cyanobacterial detritus may be a useful source for benthic invertebrates. We studied the Microcystis-derived nitrogen incorporation in benthic invertebrates in Lake Taihu using stable isotopic nitrogen (15N as a tracer. The δ15N of all organisms increased significantly with time after addition of the labeled Microcystis detritus. δ15N values of POM and periphyton peaked earlier than for benthic invertebrates, and the maximum levels were also higher than bivalves, snails and worms (Limnodrilus spp.. Among benthic invertebrates, Radix swinhoei peaked later than other invertebrates, but the maximum level and the excess 15N of the last sampling day were higher. At the end of the experiment, approximately 70% of the added 15N was retained in the benthic food web, while only a small fraction (less than 1% of the added detritus 15N occurred in the pelagic food web. Our results suggest that nitrogen from cyanobacteria can be incorporated more in benthic than pelagic food webs and cyanobacterial blooms may contribute to the development of benthic animals.

  9. Correlation between the synthetic origin of methamphetamine samples and their {sup 15}N and {sup 13}C stable isotope ratios

    Energy Technology Data Exchange (ETDEWEB)

    Billault, Isabelle [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France)]. E-mail: Isabelle.Billault@univ-nantes.fr; Courant, Frederique [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France); Pasquereau, Leo [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France); Derrien, Solene [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France); Robins, Richard J. [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France); Naulet, Norbert [Laboratoire d' Analyse Isotopique et Electrochimique de Metabolismes, CNRS UMR6006, University of Nantes, BP 92208, 44322 Nantes (France)

    2007-06-12

    The active ingredient of ecstasy, N-methyl-3,4-methyldioxyphenylisopropylamine (MDMA) can be manufactured by a number of easy routes from simple precursors. We have synthesised 45 samples of MDMA following the five most common routes using N-precursors from 12 different origins and three different precursors for the aromatic moiety. The {sup 13}C and {sup 15}N contents of both the precursors and the MDMA samples derived therefrom were measured by isotope ratio mass spectrometry coupled to an elemental analyser (EA-IRMS). We show that within-pathway correlation between the {sup 15}N content of the precursor and that of the derived MDMA can be strong but that no general pattern of correlation can be defined. Rather, it is evident that the {delta} {sup 15}N values of MDMA are strongly influenced by a combination of the {delta} {sup 15}N values of the source of nitrogen used, the route by which the MDMA is synthesised, and the experimental conditions employed. Multivariate analysis (PCA) based on the {delta} {sup 15}N values of the synthetic MDMA and of the {delta} {sup 15}N and {delta} {sup 13}C values of the N-precursors leads to good discrimination between the majority of the reaction conditions tested.

  10. Distribution and utilization of 15N in cowpeas injected into the stem under influence of water deficit.

    Science.gov (United States)

    Götz K-P; Herzog, H

    2000-01-01

    Investigations were carried out on Vigna unguiculata L. Walp. to estimate the distribution and utilization of 15N in different organs after stem injection during vegetative, flowering and pod filling stage. During flowering effects of water deficit were also examined. In well watered plants, within 4 days after injection, 65% of 15N accumulated in leaves. This was drastically reduced to 42% by water deficit. 15N accumulation in stems increased under water deficit. The translocation of 15N from the stem base to roots were not altered by water deficit. During pod filling 62% of recovered 15N in the plants had accumulated in seeds, 24% in leaves and 11% in stems within 4 days, whereas the uptake of nitrogen in pod walls and roots remained low (2%). These results demonstrate that the method of injecting very small quantities (1 mg/plant) of 15N into the stem base allows an exact and detailed quantitative assessment of N translocation/distribution with regard to different organs, different growth stages and different treatments.

  11. Sub-cellular localisation of a 15N-labelled peptide vector using NanoSIMS imaging

    International Nuclear Information System (INIS)

    Roemer, Winfried; Wu, T.-D.; Duchambon, Patricia; Amessou, Mohamed; Carrez, Daniele; Johannes, Ludger; Guerquin-Kern, Jean-Luc

    2006-01-01

    Dynamic SIMS imaging is proposed to map sub-cellular distributions of isotopically labelled, exogenous compounds. NanoSIMS imaging allows the characterisation of the intracellular transport pathways of exogenous molecules, including peptide vectors employed in innovative therapies, using stable isotopes as molecular markers to detect the compound of interest. Shiga toxin B-subunit (STxB) was chosen as a representative peptide vector. The recombinant protein ( 15 N-STxB) was synthesised in Escherichia coli using 15 NH 4 Cl as sole nitrogen source resulting in 15 N enrichment in the molecule. Using the NanoSIMS 50 ion microprobe (Cameca), different ion species ( 12 C 14 N - , 12 C 15 N - , 31 P - ) originating from the same sputtered micro volume were simultaneously detected. High mass resolving power enabled the discrimination of 12 C 15 N - from its polyatomic isobars of mass 27. We imaged the membrane binding and internalisation of 15 N-STxB in HeLa cells at spatial resolutions of less than 100 nm. Thus, the use of rare stable isotopes like 15 N with dynamic SIMS imaging permits sub-cellular detection of isotopically labelled, exogenous molecules and imaging of their transport pathways at high mass and spatial resolution. Application of stable isotopes as markers can replace the large and chemically complex tags used for fluorescence microscopy, without altering the chemical and physical properties of the molecule

  12. Investigating patterns of symbiotic nitrogen fixation during vegetation change from grassland to woodland using fine scale δ(15) N measurements.

    Science.gov (United States)

    Soper, Fiona M; Boutton, Thomas W; Sparks, Jed P

    2015-01-01

    Biological nitrogen fixation (BNF) in woody plants is often investigated using foliar measurements of δ(15) N and is of particular interest in ecosystems experiencing increases in BNF due to woody plant encroachment. We sampled δ(15) N along the entire N uptake pathway including soil solution, xylem sap and foliage to (1) test assumptions inherent to the use of foliar δ(15) N as a proxy for BNF; (2) determine whether seasonal divergences occur between δ(15) Nxylem sap and δ(15) Nsoil inorganic N that could be used to infer variation in BNF; and (3) assess patterns of δ(15) N with tree age as indicators of shifting BNF or N cycling. Measurements of woody N-fixing Prosopis glandulosa and paired reference non-fixing Zanthoxylum fagara at three seasonal time points showed that δ(15) Nsoil inorganic N varied temporally and spatially between species. Fractionation between xylem and foliar δ(15) N was consistently opposite in direction between species and varied on average by 2.4‰. Accounting for these sources of variation caused percent nitrogen derived from fixation values for Prosopis to vary by up to ∼70%. Soil-xylem δ(15) N separation varied temporally and increased with Prosopis age, suggesting seasonal variation in N cycling and BNF and potential long-term increases in BNF not apparent through foliar sampling alone. © 2014 John Wiley & Sons Ltd.

  13. Sub-cellular localisation of a 15N-labelled peptide vector using NanoSIMS imaging

    Science.gov (United States)

    Römer, Winfried; Wu, Ting-Di; Duchambon, Patricia; Amessou, Mohamed; Carrez, Danièle; Johannes, Ludger; Guerquin-Kern, Jean-Luc

    2006-07-01

    Dynamic SIMS imaging is proposed to map sub-cellular distributions of isotopically labelled, exogenous compounds. NanoSIMS imaging allows the characterisation of the intracellular transport pathways of exogenous molecules, including peptide vectors employed in innovative therapies, using stable isotopes as molecular markers to detect the compound of interest. Shiga toxin B-subunit (STxB) was chosen as a representative peptide vector. The recombinant protein ( 15N-STxB) was synthesised in Escherichia coli using 15NH 4Cl as sole nitrogen source resulting in 15N enrichment in the molecule. Using the NanoSIMS 50 ion microprobe (Cameca), different ion species ( 12C 14N -, 12C 15N -, 31P -) originating from the same sputtered micro volume were simultaneously detected. High mass resolving power enabled the discrimination of 12C 15N - from its polyatomic isobars of mass 27. We imaged the membrane binding and internalisation of 15N-STxB in HeLa cells at spatial resolutions of less than 100 nm. Thus, the use of rare stable isotopes like 15N with dynamic SIMS imaging permits sub-cellular detection of isotopically labelled, exogenous molecules and imaging of their transport pathways at high mass and spatial resolution. Application of stable isotopes as markers can replace the large and chemically complex tags used for fluorescence microscopy, without altering the chemical and physical properties of the molecule.

  14. O potencial da rotulação metabólica de 15N para a pesquisa de esquizofrenia The potential of 15N metabolic labeling for schizophrenia research

    Directory of Open Access Journals (Sweden)

    Michaela D. Filiou

    2013-01-01

    Full Text Available Pesquisas em psiquiatria ainda necessitam de estudos não dirigidos por hipóteses para revelar fundamentos neurobiológicos e biomarcadores moleculares para distúrbios psiquiátricos. Metodologias proteômicas disponibilizam uma série de ferramentas para esses fins. Apresentamos o princípio de rotulação metabólica utilizando 15N para proteômica quantitativa e suas aplicações em modelos animais de fenótipos psiquiátricos com um foco particular em esquizofrenia. Exploramos o potencial de rotulação metabólica por 15N em diferentes tipos de experimentos, bem como suas considerações metodológicas.Psychiatric research is in need of non-hypothesis driven approaches to unravel the neurobiological underpinnings and identify molecular biomarkers for psychiatric disorders. Proteomics methodologies constitute a state-of-the-art toolbox for biomarker discovery in psychiatric research. Here we present the principle of in vivo 15N metabolic labeling for quantitative proteomics experiments and applications of this method in animal models of psychiatric phenotypes, with a particular focus on schizophrenia. Additionally we explore the potential of 15N metabolic labeling in different experimental set-ups as well as methodological considerations of 15N metabolic labeling-based quantification studies.

  15. O potencial da rotulação metabólica de 15N para a pesquisa de esquizofrenia The potential of 15N metabolic labeling for schizophrenia research

    Directory of Open Access Journals (Sweden)

    Michaela D Filiou

    2012-01-01

    Full Text Available Pesquisas em psiquiatria ainda necessitam de estudos não dirigidos por hipóteses para revelar fundamentos neurobiológicos e biomarcadores moleculares para distúrbios psiquiátricos. Metodologias proteômicas disponibilizam uma série de ferramentas para esses fins. Apresentamos o princípio de rotulação metabólica utilizando 15N para proteômica quantitativa e suas aplicações em modelos animais de fenótipos psiquiátricos com um foco particular em esquizofrenia. Exploramos o potencial de rotulação metabólica por 15N em diferentes tipos de experimentos, bem como suas considerações metodológicas.Psychiatric research is in need of non-hypothesis driven approaches to unravel the neurobiological underpinnings and identify molecular biomarkers for psychiatric disorders. Proteomics methodologies constitute a state-of-the-art toolbox for biomarker discovery in psychiatric research. Here we present the principle of in vivo 15N metabolic labeling for quantitative proteomics experiments and applications of this method in animal models of psychiatric phenotypes, with a particular focus on schizophrenia. Additionally we explore the potential of 15N metabolic labeling in different experimental set-ups as well as methodological considerations of 15N metabolic labeling-based quantification studies.

  16. Fate of nitrogen ({sup 15}N) from velvet bean in the soil-plant system

    Energy Technology Data Exchange (ETDEWEB)

    Scivittaro, Walkyria Bueno [Empresa Brasileira de Pesquisa Agropecuaria, Pelotas, RS (Brazil). Clima Temperado; Muraoka, Takashi; Boaretto, Antonio Enedi; Trivelin, Paulo Cesar Ocheuze [Centro de Energia Nuclear na Agricultura, Piracicaba, SP (Brazil). Lab. de Fertilidade do Solo]. E-mail: wbscivit@cpact.embrapa.br

    2004-04-01

    Because of their potential for N{sub 2} biological fixation, legumes are an alternative source of nitrogen to crops, and can even replace or supplement mineral fertilization. A greenhouse experiment was carried out to evaluate temporal patterns of velvet bean (Mucuna aterrima) green manure release of nitrogen to rice plants, and to study the fate of nitrogen from velvet bean in rice cultivation. The isotopic dilution methodology was used. Treatments consisted of a control and 10 incubation periods of soil fertilized with {sup 15}N-labeled velvet bean (0, 20, 40, 60, 90, 120, 150, 180, 210, and 240 days). The plant material was previously chopped, sifted (10 mm mesh sieve) and oven-dried (65 deg C). Incubation of the plant material (2.2 g kg{sup -1} soil) was initiated by the longest period, in order to synchronize the planting of the test crop, rice (Oryza sativa), at time zero for all treatments. Green manure incorporation promoted increases in rice dry matter yield and nitrogen uptake. These variables showed maximum values at incubation periods of 38 and 169 days, respectively. Green manure nitrogen utilization by rice plants was highest at an incubation period corresponding to 151 days. More than 60% of the green manure nitrogen remained in the soil after rice cultivation. The highest green manure nitrogen recovery from the soil-plant system occurred at an incubation period equivalent to 77 days. (author)

  17. Nitrogen fertilization management and nitrogen (15N) utilization by corn crop in red latosol

    International Nuclear Information System (INIS)

    Duete, Robson Rui Cotrim; Ambrosano, Edmilson Jose

    2008-01-01

    Nitrogen is the nutrient that is most absorbed by corn crop, influences grain yield most, and requires the most complex management. The objective of this work was to evaluate the effect of nitrogen (urea 15 N) rate and split-applications, on grain yield, N fertilizer utilization and amount of soil native N absorbed by corn crop in a Red Latosol. The experiment was arranged in a randomized complete block design, with nine treatments and four replications, represented by five N rates: 0, 55, 95, 135 and 175 kg ha -1 N, 15 kg of N applied at sowing, and the remaining amount in different split-applications: 40 and 80 kg ha -1 applied in single rates in the 8-leaf stage or half in the 4-leaf stage + half in the 8-leaf stage; 120 kg ha -1 split in 1/2 + 1/2 or 1/3 + 1/3 + 1/3 in the 4, 8 or 12-leaf stage; 160 kg ha-1 split in 1/4 + 3/8 + 3/8 or 1/4 + 1/4 + 1/4 + 1/4 in the 4, 8, 12-leaf stages or at flowering and pollination. The N fertilizer use by corn was, on average, 39 %, and the soil was the main source of the nutrient for the crop. With three split applications of 135 kg ha-1 N, until 8 leaves, the N fertilizer use is most efficient (52 %) and the grain yield highest (author)

  18. Conformational analysis of capsaicin using 13C, 15N MAS NMR, GIAO DFT and GA calculations

    Science.gov (United States)

    Siudem, Paweł; Paradowska, Katarzyna; Bukowicki, Jarosław

    2017-10-01

    Capsaicin produced by plants from genus Capsicum exerts multiple pharmacological effects and has found applications in food and pharmaceutical industry. The alkaloid was studied by a combined approach: solid-state NMR, GA conformational search and GIAO DFT methods. The 13C CPMAS NMR spectra were recorded using variable contact time and dipolar dephasing experiments. The results of cross-polarization (CP) kinetics, such as TCP values and long T1ρH (100-200 ms), indicated that the capsaicin molecule is fairly mobile, especially at the end of the aliphatic chain. The15N MAS NMR spectrum showed one narrow signal at -255 ppm. Genetic algorithm (GA) search with multi modal optimization was used to find low-energy conformations of capsaicin. Theoretical GIAO DFT calculations were performed using different basis sets to characterize five selected conformations. 13C CPMAS NMR was used as a validation method and the experimental chemical shifts were compared with those calculated for selected stable conformers. Conformational analysis suggests that the side chain can be bent or extended. A comparison of the experimental and the calculated chemical shifts indicates that solid capsaicin does not have the same structure as those established by PWXRD.

  19. Study on the utilization of N fertilizers by labelling with 15N in a microplot experiment

    International Nuclear Information System (INIS)

    Latkovics, I.

    1982-01-01

    The effect and residual effect of urea and NH 4 NO 3 on the dry matter yield and N uptake of rye-grass and Sudan grass, as well as on the N status of the soil and the distribution of N within the soil profile were studied with 15 N indication on a chernozem-like calcareous sandy soil in an isolated microplot experiment. It has been found that 57-79% of the N contents of the first cuttings came from the fertilizer, and the percentage N amounts decreased with each cutting. Under the given experimental conditions there was no significant difference between the N amounts taken up from urea or from NH 4 NO 3 . Rye-grass utilized N both from urea and NH 4 NO 3 in the same degree (55%), while Sudan grass utilized 29.8% from urea and 36.1% from NH 4 NO 3 . Depending on the treatment, 22.8-31.7% of fertilizer-N was found in the 0-120 cm layer of the soil, while the larger part (74.8-84.6%) of this amount accumulated in the upper 40 cm layer. The amount of fertilizer-N not recovered (and thus 'lost' for the plants) was 13.3-21.6% in the case of rye-grass and 34.4-43.1% of Sudan grass. (author)

  20. Nitrogen management in tomato (Lycopersicon esculentum) using 15N-enriched fertilizer

    International Nuclear Information System (INIS)

    Shivananda, T.N.; Iyengar, B.R.V.; Kotur, S.C.

    1996-01-01

    An experiment was conducted during 1991 to study nitrogen management using 15 N-enriched fertilizer, to achieve economy in fertilizer N input by reduction and postponement of the basal dose in Arka Vikas tomato (Lycopersicon esculentum Miller nom. cons). Application of 90 kg N/ha in 3 equal splits at 10, 30 and 50 days after transplanting did not show any reduction in total N uptake, dry-matter and fruit yields compared with 120 kg N/ha applied in 3 splits (60 kg N/ha basal and 30 kg top-dressed 20 and 40 days after transplanting). Band application of the basal dose and top-dressing at 20 days after transplanting resulted in higher N derived from fertilizer (Ndff), its uptake and utilization. Top-dressing of 30 or 40 kg N/ha at 10 days after transplanting resulted in better utilization than broadcasting the basal dose of 60 kg N/ha. Application at 40-50 days after transplanting showed poor uptake and utilization of applied N. The succeeding Arka Kalyan onion (Allium cepa L.) utilized 2.95-6.37% residual N, the highest being from the split application at 40 days after transplanting. Thus there was economy in fertilizer N input and higher carry-over of residual N for determinate cultivar of tomato be delaying as well as reducing the basal dose and confining the top-dressing to 30 days after transplanting. (author)

  1. Quantification Of 15N Internal Transformation To Assess Nitrogen Supply Capacity In Deforested Soil

    International Nuclear Information System (INIS)

    Handayani, I.P.; Prawito, P.; Sisworo, E.L.

    2002-01-01

    Quantification of deforested soil's capacity to supply available N via mineralization and immobilization using 15N pool dilution is crucial to make fertilizer recommendation. The objective of this research was to measure the soil's capacity to minemlize and ilmnobilize N, so that the actual value of available N released by soil can be predicted. The results showed that Imperata grassland released the highest available N (amonium + nitrate) about 33.93 mg/kg/d and can immobilize 11.68 mg/kg/d of N. On the other hand, agriculture lields had the lowest inorganic N by nearly 23.15 mg/kg/d, and no immobilization occurred. The implication is that agriculture fields have a very low labile and stabile pool N (nearly 0), while Imperata grassland have capacity to store more pool N into labile or stabil pool (about 34%). In conclusion, dynamics of N cycling in ecosystem are dependent upon the content of pool C-N utilized by microorganisms and plants

  2. Fertilizer use efficiency by spring potato in Central Beqaa' using 15N

    International Nuclear Information System (INIS)

    Atallah, Therese; Darwich, Talal; Haj Hasan, S.; Chranek, A.

    1999-01-01

    Full text.The two year experiment aimed at studying the impact of the modality of fertilizer application and the irrigation techniques on spring potatoes yield parameters with the use of 15 N. Potato (spunta) was planted in 1997 and 1998 on clay soil in Tel Amara, Central Beqaa, in radomized block design. It consisted of five treatments and four replicates. Treatments (N1=240, N2=360, N3=480 Kg N/ha for 1997 and N1-120, N2=240, N3=360 Kg N/ha for 1998) had the goal of studying the effect of three rates of N fertigation on potato plant performance and production. We compared full fertigation with conventional fertilizer application and irrigation with drip and macro sprinkler. Water demands and irrigation were scheduled according to the mean annual potential evapotranspiration in 1997 and class A pan in 1998, and monitored by the neutron probe and tensiometers. Results showed that, at jarvest, both crops followed the same yield pattern. The highest tuber yield was obtained from N1 and the lowest from N3. These values were 58 ton/ha for 1997 and 32.5 ton/ha for 1998 trials respectively. The 1998 spring crop

  3. Nitrogen utilization of vegetables grown under plastic greenhouse conditions in Ankara using 15N technique

    International Nuclear Information System (INIS)

    Halitligil, M.B.; Kislal, H.; Sirin, H.; Sirin, C.; Kilicaslan, A.

    2004-01-01

    In order to find suitable varieties of tomato, pepper and cucumber for plastic greenhouse conditions in Ankara and eventually to identify the best N fertilizer rate greenhouse experiments were conducted for two years. Yazgi F 1 variety for tomato, Hizir F 1 variety for cucumber and Serademre 8 variety for pepper were chosen to be the suitable varieties to grow in the plastic greenhouse conditions in Ankara. Five N treatments [N 0 =0, N 1 =150, N 2 =300, and N 3 =450 kg/ha; also, soil N application treatment (N soil ) equivalent to the fertigation treatment of 300 kg/ha was included for tomato and pepper, however N rates for cucumber was 131, 266 and 339 kg N/ha; N soil being 266 kg N/ha] were investigated using 15 N labeled urea fertilizer. Significantly higher marketable fresh fruit and total dry matter yields and N uptakes values were obtained from N 3 treatments for tomato and cucumber, but from N 2 treatment for pepper. Also, significantly higher yields, N uptakes and % NUE values were obtained when the same amount of N fertilizer is applied through fertigation compared to the treatment where N fertilizer applied to the soil then drip irrigated. (author)

  4. Studies on the protein and amino acid metabolism of laying hens using 15N-labelled casein. 8

    International Nuclear Information System (INIS)

    Richter, G.

    1977-01-01

    Four colostomized Leghorn hens were fed, during 6 days, 15 N-labelled casein as sole protein source. Two animals were slaughtered 48 hours, the other two 144 hours after the last 15 N-application. The share of TCE-soluble N in total N averaged 16% for the body parts analysed, i.e. meat, bone, liver, kidneys, oviducts, residual viscera and other. The variation of the lysine, histidine and arginine levels in the body parts ranged from 3.6 to 7.9 g, 1.1 to 3.7 g and 6.4 to 7.4 g in 16.7 g hydrolysate N, respectively. Except for feathers, the analysed body parts contained an excess amount of heavy nitrogen. The degree of labelling was found to depend on the time of slaughtering after the tracer application. In the liver and in the oviduct being metabolically active organs, the 15 N-excess in the total N fraction decreased by 45% between the 2nd and the 6th days after 15 N-feeding, whilst in the meat it went down by 20%. The decline of the 15 N-concentration in the TCE-soluble N compounds was faster than in the total N-fraction. Out of the body samples analysed, the lysine of the liver having 0.26 atom% 15 N-excess was found to be more strongly labelled in hens 1 and 2. The amino acid arginine reached about the same level of labelling, the 15 N-frequency of histidine being the lowest. (author)

  5. Stellar Origin of 15N-rich Presolar SiC Grains of Type AB: Supernovae with Explosive Hydrogen Burning

    International Nuclear Information System (INIS)

    Liu, Nan; Nittler, Larry R.; Alexander, Conel M. O’D.; Wang, Jianhua; Pignatari, Marco

    2017-01-01

    We report C, N, and Si isotopic data for 59 highly 13 C-enriched presolar submicron- to micron-sized SiC grains from the Murchison meteorite, including eight putative nova grains (PNGs) and 29 15 N-rich ( 14 N/ 15 N ≤ solar) AB grains, and their Mg–Al, S, and Ca–Ti isotope data when available. These 37 grains are enriched in 13 C, 15 N, and 26 Al with the PNGs showing more extreme enhancements. The 15 N-rich AB grains show systematically higher 26 Al and 30 Si excesses than the 14 N-rich AB grains. Thus, we propose to divide the AB grains into groups 1 ( 14 N/ 15 N < solar) and 2 ( 14 N/ 15 N ≥ solar). For the first time, we have obtained both S and Ti isotopic data for five AB1 grains and one PNG and found 32 S and/or 50 Ti enhancements. Interestingly, one AB1 grain had the largest 32 S and 50 Ti excesses, strongly suggesting a neutron-capture nucleosynthetic origin of the 32 S excess and thus the initial presence of radiogenic 32 Si ( t 1/2 = 153 years). More importantly, we found that the 15 N and 26 Al excesses of AB1 grains form a trend that extends to the region in the N–Al isotope plot occupied by C2 grains, strongly indicating a common stellar origin for both AB1 and C2 grains. Comparison of supernova models with the AB1 and C2 grain data indicates that these grains came from supernovae that experienced H ingestion into the He/C zones of their progenitors.

  6. Effects of compost application on fruits yields, sugar and mineral contents and δ15N values of tomato fruits

    International Nuclear Information System (INIS)

    Nakano, Akimasa; Uehara, Yoichi; Yamauchi, Akira

    2003-01-01

    We examined the effects of chemical fertilizer and compost application on the yields and sugar and mineral content of tomato (Lycopersicon esculentum Mill. Saturn) in an isolated bed. Five treatments were conducted within a two-year period of 4 continuous croppings. CDU and LSR (Low-sulfate slow-release fertilizer) were used for the chemical fertilizer plots. A mixture of cattle manure and CDU (CM + CDU), a mixture of poultry manure and CDU (PM + CDU), and mixture of cattle and poultry manure (PM + CM) plots were arranged as compost-using plots. We also measured the δ 15 N values of tomatoes and the soils of each treatment, and estimated the correlation of the δ 15 N values between fruits and soil to certify compost applied products. We did not find any reproductive differences in the yield or sugar content among the treatments. As to inorganic content of tomatoes, there were no significant differences except for Mg content among the plots. These results showed that it is difficult to assay regular benefit of organic fertilizer application to tomato yields and quality. On the other hand, δ 15 N values of tomato fruits showed significant differences among fertilizer applications. δ 15 N values of the chemical fertilizer were +1.6 per mille and -1.1% for CDU and LSR, respectively. Those of mixture of chemical and compost were +12.2 per mille and +11.2 per mille for CM + CDU and PM + CDU, respectively. The mixture of PM and CM showed the highest δ 15 N values (17.9 per mille) among the treatments. δ 15 N values of the soils and fruits reflected those of the fertilizers and were positively correlated (R 2 = 0.89). It may be possible to use δ 15 N values as an indicator of organic products by setting the threshold point, e.g. +5.0 per mille, to distinguish them from the products cultivated with chemical fertilizer. (author)

  7. The NTS-DBL2X region of VAR2CSA induces cross-reactive antibodies that inhibit adhesion of several Plasmodium falciparum isolates to chondroitin sulfate A.

    Science.gov (United States)

    Bigey, Pascal; Gnidehou, Sédami; Doritchamou, Justin; Quiviger, Mickael; Viwami, Firmine; Couturier, Aude; Salanti, Ali; Nielsen, Morten A; Scherman, Daniel; Deloron, Philippe; Tuikue Ndam, Nicaise

    2011-10-01

    Binding to chondroitin sulfate A by VAR2CSA, a parasite protein expressed on infected erythrocytes, allows placental sequestration of Plasmodium falciparum-infected erythrocytes. This leads to severe consequences such as maternal anemia, stillbirths, and intrauterine growth retardation. The latter has been clearly associated to increased morbidity and mortality of the infants. Acquired anti-VAR2CSA antibodies have been associated with improved pregnancy outcomes, suggesting a vaccine could prevent the syndrome. However, identifying functionally important regions in the large VAR2CSA protein is difficult. Using genetic immunization, we raised polyclonal antisera against overlapping segments of VAR2CSA in mice and rabbits. The adhesion-inhibition capacities of induced antisera and of specific antibodies purified from plasma of malaria-exposed pregnant women were assessed on laboratory-adapted parasite lines and field isolates expressing VAR2CSA. Competition enzyme-linked immunosorbent assay (ELISA) was employed to analyze functional resemblance between antibodies induced in animals and those naturally acquired by immune multigravidae. Antibodies targeting the N-terminal sequence (NTS) up to DBL2X (NTS-DBL2X) efficiently blocked parasite adhesion to chondroitin sulfate A in a manner similar to that of antibodies raised against the entire VAR2CSA extracellular domain. Interestingly, naturally acquired antibodies and those induced by vaccination against NTS-DBL2X target overlapping strain-transcendent anti-adhesion epitopes. This study highlights an important step achieved toward development of a protective vaccine against placental malaria.

  8. Spin and parity determinations of excited 15N based on polarized and unpolarized 12C(7Li, α)15N reaction data at E lab = 34 MeV

    International Nuclear Information System (INIS)

    Rodriguez, F.J.; Liendo, J.A.; Roeder, B.T.; Weintraub, W.; Kemper, K.W.; Keeley, N.; Marechal, F.

    2007-01-01

    From an experiment conducted at the Florida State University Accelerator Laboratory with a 34 MeV polarized 7 Li beam bombarding a 12 C target, we have obtained angular distributions and analyzing powers for states of 15 N up to 20 MeV in excitation energy. This study not only offers the possibility to assign spin and parity to several states in 15 N, but also serves to obtain nuclear potential parameters used in Distorted Wave Born (DWBA) and Coupled Channel Born (CCBA) Approximations to generate theoretical angular distributions and vector analyzing powers that give the best description of the experimental data. Under the assumption that the reaction mechanism is a three nucleon transfer, the determination of shell model nucleonic configurations and spectroscopic factors is possible for the 15 N states studied

  9. Glacial–interglacial dynamics of Antarctic firn columns: comparison between simulations and ice core air-δ15N measurements

    Directory of Open Access Journals (Sweden)

    E. Capron

    2013-05-01

    Full Text Available Correct estimation of the firn lock-in depth is essential for correctly linking gas and ice chronologies in ice core studies. Here, two approaches to constrain the firn depth evolution in Antarctica are presented over the last deglaciation: outputs of a firn densification model, and measurements of δ15N of N2 in air trapped in ice core, assuming that δ15N is only affected by gravitational fractionation in the firn column. Since the firn densification process is largely governed by surface temperature and accumulation rate, we have investigated four ice cores drilled in coastal (Berkner Island, BI, and James Ross Island, JRI and semi-coastal (TALDICE and EPICA Dronning Maud Land, EDML Antarctic regions. Combined with available ice core air-δ15N measurements from the EPICA Dome C (EDC site, the studied regions encompass a large range of surface accumulation rates and temperature conditions. Our δ15N profiles reveal a heterogeneous response of the firn structure to glacial–interglacial climatic changes. While firn densification simulations correctly predict TALDICE δ15N variations, they systematically fail to capture the large millennial-scale δ15N variations measured at BI and the δ15N glacial levels measured at JRI and EDML – a mismatch previously reported for central East Antarctic ice cores. New constraints of the EDML gas–ice depth offset during the Laschamp event (~41 ka and the last deglaciation do not favour the hypothesis of a large convective zone within the firn as the explanation of the glacial firn model–δ15N data mismatch for this site. While we could not conduct an in-depth study of the influence of impurities in snow for firnification from the existing datasets, our detailed comparison between the δ15N profiles and firn model simulations under different temperature and accumulation rate scenarios suggests that the role of accumulation rate may have been underestimated in the current description of firnification

  10. Isotopic evaluations of dynamic and plant uptake of N in soil amended with 15N-labelled sewage sludge

    International Nuclear Information System (INIS)

    Kchaou, R.; Khelil, M. N.; Rejeb, S.; Gharbi, F.; Henchi, B.; Hernandez, T.; Destain, J. P.

    2010-01-01

    Field experiments were conducted to evaluate the use of a novel 15N isotope technique for comparing the dynamics of N derived from sewage sludge applied to sorghum to the dynamics of N derived from the commercial fertilizer, urea. The treatments included a control, sludge applied at three rates (3, 6 and 9 t/ha, or 113, 226 and 338 kg N/ha) and N-urea applied at three rates (150, 250 and 350 kg N/ha). Recovery of 15N -labelled sludge was similar for the different nitrogen rates applied , with a mean value of 27%. However, the recovery of 15N -urea decreased as the rate of N application increased (from 38% to 27%). Approximately 22% and 19% of the 15N from sludge and urea, respectively, remained in the 0-60 cm layer of soil, most of which was present in the 0-20 cm layer. Furthermore, losses of 15N -labelled fertilizer were not affected by the N fertilization source, and the greatest losses, which were measured in response to the highest N application rate, were 59%. (authors)

  11. Sources of nitrate in the Arno River waters: Constraints from d15N and d18O

    Science.gov (United States)

    Nisi, Barbara; Vaselli, Orlando; Buccianti, Antonella; Silva, Steven R.

    2005-01-01

    Running waters in anthropogenically affected areas are susceptible to nitrate contamination. Source identification is a fundamental step for the development of effective remediation. Previous studies pointed to pollution by nitrogen-bearing contaminants in the Arno Basin. In this paper, eleven surface water samples have been analysed for main and trace components and 15N/14N and 18O/16O ratios, with the aim of identifying for the first time the origin of nitrate in the Arno River Basin so that further investigations can appropriately be designed. d18O(NO3)and d15N(NO3) values have allowed to hypothesise the main sources of nitrate, as follows: i) mineralized fertilizer, ii) soil-organic nitrogen, iii) manure and septic waste. The anomalously high d15N and d18O values in the Chiana (d15N=24.9‰ and d18O=15.5‰) and Usciana tributaries (d15N=30.1‰ and d18O=7.2‰) show a low probability of belonging to the same population as that of the other samples and can be related to denitrification process of nitrate from animal waste/sewage and/or an industrial process (e.g. tanneries).

  12. δ 15N Studies of Nitrogen Use by the Red Mangrove, Rhizophora mangle L. in South Florida

    Science.gov (United States)

    Fry, B.; Bern, A. L.; Ross, M. S.; Meeder, J. F.

    2000-02-01

    To help define nitrogen (N) sources and patterns of N processing in mangrove ecosystems, mangrove leaf nitrogen contents and δ 15N values were assayed in three marshes along the south Florida coast. In each marsh, leaf samples were collected from dwarf mangroves at interior locations and taller mangroves at the ocean fringe. Leaf % N and δ 15N values did not differ consistently between dwarf and tall mangroves, even though there were large variations in δ 15N (18‰ range, -5 to +13‰) and % N (1·2% range, 0·9-2·1%). Highest % N and δ 15N values occurred along the western margin of Biscayne Bay where canals draining agricultural lands deliver high-nitrate waters to fringing mangrove marshes. High mangrove δ 15N values may be good biomonitors of anthropogenic N loading to south Florida estuaries. Lower values likely reflect less anthropogenic N entering the mangrove marshes, as well as differences in plant physiology that occur along the fringe-dwarf gradient.

  13. Use of 15N enriched plant material for labelling of soil nitrogen in legume dinitrogen fixation experiments

    International Nuclear Information System (INIS)

    Jensen, E.S.

    1989-06-01

    The soil nitrogen in a field plot was labelled with nitrogen-15 (15N) by incorporating labelled plant material derived from previous experiments. The plot was used the following 3 years for determination of the amount of N2 fixed by different leguminous plants. The atom % 15N excess in grains of cereals grown as reference crops was 0.20, 0.05 and 0.03 in the 3 years, respectively. In the first year the level of enrichment was adequate for estimating symbiotic nitrogen fixation. In the second and third year lack of precision in determination of the 15N/14N ratios of legume N, may have caused an error in estimates of nitrogen fixation. About 23% of the labelled N was taken up by plants during the 3 years of cropping; after 4 years about 44% of the labelled N was found still to be present in the top soil. The labelling of the soil nitrogen with organic bound 15N, compared to adding mineral 15N at sowing, is advantageous because the labelled N is released by mineralization so that the enrichment of the plant available soil N pool become more uniform during the growth season; and high levels of mineral N, which may depress the fixation process, is avoided. (author) 7 tabs., 1 ill., 30 refs

  14. First Measurement of the 14N/15N Ratio in the Analog of the Sun Progenitor OMC-2 FIR4

    Science.gov (United States)

    Kahane, Claudine; Jaber Al-Edhari, Ali; Ceccarelli, Cecilia; López-Sepulcre, Ana; Fontani, Francesco; Kama, Mihkel

    2018-01-01

    We present a complete census of the 14N/15N isotopic ratio in the most abundant N-bearing molecules toward the cold envelope of the protocluster OMC-2 FIR4, the best known Sun progenitor. To this scope, we analyzed the unbiased spectral survey obtained with the IRAM 30 m telescope at 3, 2, and 1 mm. We detected several lines of CN, HCN, HNC, HC3N, N2H+, and their respective 13C and 15N isotopologues. The lines’ relative fluxes are compatible with LTE conditions, and moderate line opacities have been corrected via a population diagram method or theoretical relative intensity ratios of the hyperfine structures. The five species lead to very similar 14N/15N isotopic ratios, without any systematic difference between amine- and nitrile-bearing species as previously found in other protostellar sources. The weighted average of the 14N/15N isotopic ratio is 270 ± 30. This 14N/15N value is remarkably consistent with the [250–350] range measured for the local galactic ratio but significantly differs from the ratio measured in comets (around 140). High-angular resolution observations are needed to examine whether this discrepancy is maintained at smaller scales. In addition, using the CN, HCN, and HC3N lines, we derived a 12C/13C isotopic ratio of 50 ± 5.

  15. The use of 15N-labelled dinitrogen in the study of nitrogen fixation by blue-green algae

    International Nuclear Information System (INIS)

    Jones, J.

    1985-01-01

    Prior to the development of the acetylene reduction technique 15 N was used as the main qualitative and quantitative measure of nitrogen fixation by free-living cyanobacteria in a variety of aquatic and terrestrial habitats. Despite its expense and the technical difficulty, 15 N is a major tool in the study of cyanobacteria, for example, incorporation of 15 N 2 is the definitive test for nitrogen fixation; it is used in the determination of the correct ratio of acetylene reduction to nitrogen fixation, in in situ nitrogen fixation assays, in tracing the formation and fate of extra-cellular nitrogen and in measuring the turnover and grazing rates of cyanobacterial intra-cellular nitrogen. These latter studies show that 15 N-labelled extra-cellular nitrogen can serve as nitrogen sources for a variety of bacteria, fungi, algae and higher plants, and that cyanobacteria are graced and digested by a variety of animals. The turnover rates of cyanobacterial 15 N-labelled cells are dependent on the type of cell, species, environmental conditions and the availability of degrading organisms. The breakdown products are rapidly mineralised and used as nitrogen sources by higher plants. (author)

  16. Evaluating the potential of nitrogen fixing of plants in the forest ecosystem by using natural 15N abundance method

    International Nuclear Information System (INIS)

    Yao Yunyin; Chen Ming; Ma Changlin; Wang Zhidong; Hou Jingqing; Zhang Lihong; Luo Yongyun

    1991-02-01

    The potential of nitrogen fixing of plants was evaluated by using the variation of nitrogen isotope component in leaves and stems of plants and in soil. It gives a feasible method to investigate the nitrogen fixing potential of wild plants from atmosphere in the forest ecosystem. Plant samples and soil were collected from Natural Protecting Area of Xiaowutai Mountain in Hebei Province. The contents of N and 15 N in the legumes and other plants was obviously different from the value in soil. The δ 15 N value in leaves and stems of non-legumes plants was obviously different from the value in soil. The δ 15 N value of legumes was close to the value in the atmosphere (0 per mille). In the estimating of %Ndfa of nitrogen fixing plants in the forest ecosystem, the selection of non-nitrogen-fixing plants as reference is discussed. The chinese pine and a few non-legumes may have the potential of nitrogen fixing, because the δ 15 N value is close to the δ 15 N value in the atmosphere

  17. Ultra-violet absorption cross sections of isotopically substituted nitrous oxide species: 14N14NO, 15N14NO, 14N15NO and 15N15NO

    Directory of Open Access Journals (Sweden)

    P. von Hessberg

    2004-01-01

    Full Text Available The isotopically substituted nitrous oxide species 14N14NO, 15N14NO, 14N15NO and 15N15NO were investigated by ultra-violet (UV absorption spectroscopy. High precision cross sections were obtained for the wavelength range 181 to 218nm at temperatures of 233 and 283K. These data are used to calculate photolytic isotopic fractionation constants as a function of wavelength. The fractionation constants were used in a three-dimensional chemical transport model in order to simulate the actual fractionation of N2O in the stratosphere, and the results were found to be in good agreement with field studies.

  18. Dynamics of nitrogen in an oxic paleudalf soil with the incorporation of 15N-tagged organic nitrogen (maize straw) and 15N-tagged mineral nitrogen (ammonium sulphate)

    International Nuclear Information System (INIS)

    Freitas, J.R. de.

    1984-12-01

    An experiment, carried out under field conditions in 12 lysimeters, each containing 3.0 ton of Oxic Paleudalf soil with four replicates, is described. This objective is labelling soil organic N. Nitrogen was incorporated into soil as maize straw, non-labelled and labelled with 15 N and ammonium sulphate - 15 N. The soil was sampled every 15 days in three different depths. N as NH + 4 , NO - 3 , total-N and (%)C and (%) moisture was analysed. (M.A.C.) [pt

  19. An upstream open reading frame controls translation of var2csa, a gene implicated in placental malaria

    DEFF Research Database (Denmark)

    Amulic, Borko; Salanti, Ali; Lavstsen, Thomas

    2009-01-01

    to only be expressed in the presence of a placenta, suggesting that its expression is actively repressed in men, children or non-pregnant women; however, the mechanism of repression is not understood. Using cultured parasite lines and reporter gene constructs, we show that the gene encoding VAR2CSA...... contains a small upstream open reading frame that acts to repress translation of the resulting mRNA, revealing a novel form of gene regulation in malaria parasites. The mechanism underlying this translational repression is reversible, allowing high levels of protein translation upon selection, thus...

  20. Using 15N to study the effect of additament on N balance of urea

    International Nuclear Information System (INIS)

    Pan Jiarong; Wen Xianfang; Liu Baojun; Zheng Xingyun

    1994-08-01

    It was showed that the dry weight and grain yield of rice were 2.3%∼12.7% and 1.6%∼11.8% higher respectively than those of urea applied alone when urea applied with cow slurry, rare-earth, Maifanshi, calcium chloride and dicyandiamine (DCD). Among the treatments, DCD and Maifanshi increased the nitrogen use efficiency of urea from 4.3 kg grain/kg N applied when urea applied alone to 10.7 kg grain and 12.5 kg grain per kg N applied. It was shown from 15 N tracing experiment that the nitrogen uptake efficiency of urea for rice when applied alone was 20.6% while 25.9, 26.3, 24.0, 28.3 and 27.9% respectively when applied with cow slurry, rare-earth, maifanshi, calcium chloride and DCD. Application of urea with above various materials contributed to a apparent effect on increase of nitrogen residue in soil and nitrogen loss (particularly in loss by air) from urea, among which , the best effect was obtained on nitrogen residue in soil from urea when applied with cow slurry and rare-earth, the residues were 30.3% and 27.3% of applied nitrogen respectively, and DCD could decrease the nitrogen loss greatly, from 57.5% of applied nitrogen when applied alone to 36.3% of applied nitrogen. It was also showed that the difference of effect on kinetics of soil available nitrogen between one treatment and another was not significant, but significant difference existed in effect of different treatments on loss of soil nitrogen and soil nitrogen mineralization. Compared with labelled urea applied alone, application with cow slurry and DCD resulted in great decrease in loss of soil nitrogen and soil nitrogen mineralization while not apparent effect for application with rare-earth, calcium chloride and Maifanshi. (7 tabs.)

  1. Studies of the endogeneous N metabolism in 15N-labelled pigs. 3

    International Nuclear Information System (INIS)

    Bergner, U.; Uecker, E.; Rossow, N.; Simon, O.; Bergner, H.

    1984-01-01

    4 pigs were labelled over a period of 10 days with 15 N in a fishmeal diet (1), a fishmeal diet + partly hydrolyzed straw meal (2), a horse bean diet (3) and a horse bean diet + partly hydrolyzed straw meal (4). After 24 hours fasting the animals were provided with simple fistulae in the upper part of the small intestine. After a further fasting period of 24 h all four pigs received a 14 C-leucine injection and the fistula secretion was collected in the subsequent 24 h. After feeding diets without straw meal (1 and 3) there were distinct differences in the secretion in compared to feeding with straw meal supplements (2 and 4) despite the long fasting period (48-72 h). 14 C activity could already detected in the TCA-precipitable fraction of the secretion after 3-6 min of the injection in 1 and 3 but only 20 to 25 min after the 14 C leucine injection in 2 and 4. The specific 14 C-leucine activity of the TCA-soluble fraction of the secretion was, after straw meal supplementation to the fishmeal diet, 15 times higher 25 min after the 14 C-leucine injection, 25 times higher after 70 min, 36 times after 2 h and 1.8 times after 4 h than without straw meal supplementation. For all four diets a specific correlation could be ascertained between the increase of 14 C activity/mg N in the TCA-soluble fraction and the increasing crude fiber content in the diet between 25 and 180 min after the injection. Furthermore, a distinctly decreased N secretion/h could be ascertained with the increasing crude fiber content in the diet. The influence of the crude fiber on the parameters mentioned is seen in the changed osmotic conditions in the secretion, which may be caused by the changed regulation by hormones of the gastrointestinal tract. (author)

  2. Utilization of residual nitrogen (15N) from cover crop and urea by corn

    International Nuclear Information System (INIS)

    Silva, Edson Cabral da; Muraoka, Takashi; Trivelin, Paulo Cesar Ocheuze; Buzetti, Salatier; Veloso, Marcos Emanuel da Costa

    2006-01-01

    The majority of N from mineral fertilizers and cover crops is usually not used by the very next corn crop, but can be absorbed by follow-up crops. The objective of this study was to evaluate the use of residual nitrogen from urea, sunnhemp (Crotalaria juncea) and millet (Pennisetum americanum) labeled with 15 N, applied to no-tillage corn in the previous growing season, in a Red Latosol of the Cerrado. The study was conducted in an experimental farm of the Sao Paulo State University (UNESP), Ilha Solteira, in Selviria county (MS), Brazil, in different areas. The experiment had a randomized complete block design, with 15 treatments and four replications. Treatments were applied to corn crop in the 2001/02 and 2003/04 growing seasons. They were distributed in a 3 x 5 factorial layout, representing the combination of three cover crops: sunnhemp, millet and spontaneous vegetation (fallow) and five N rates (as urea): 0, 30, 80, 130, and 180 kg ha-1 of N. After corn harvest, the two areas were followed in the dry season and were followed by corn crop in the 2002/03 (experiment 1) and 2003/04 (experiment 2) growing seasons, using the same fertilizer rate on all plots to distinguish the residual effect of N sources. The average use of residual N from the millet and sunnhemp residues (above-ground part) by corn crop was less than 3.5 and 3 %, respectively, of the initial amount. The corn uptake of residual N from urea increased in a quadratic manner in experiment 1 and linearly in experiment Two as a response to the applied N rates, and the recover was below 3 %. The cover crop type did not affect the use of residual N of urea by corn, and vice-versa. (author)

  3. Nitrate removal in stream ecosystems measured by 15N addition experiments: 2. Denitrification

    Energy Technology Data Exchange (ETDEWEB)

    Mulholland, Patrick J [ORNL; Hall, Robert [University of Wyoming, Laramie; Sobota, Daniel [Oregon State University; Dodds, Walter [Kansas State University; Findlay, Stuart [Institute of Ecosystem Studies; Grimm, Nancy [Arizona State University; Hamilton, Stephen [Michigan State University, East Lansing; McDowell, William [University of Hew Hampshire; O' Brien, Jon [Michigan State University, East Lansing; Tank, Jennifer [University of Notre Dame, IN; Ashkenas, Linda [Oregon State University, Corvallis; Cooper, Lee W [ORNL; Dahm, Cliff [University of New Mexico, Albuquerque; Gregory, Stanley [Oregon State University, Corvallis; Johnson, Sherri [Oregon State University; Meyer, Judy [University of Georgia, Athens, GA; Peterson, Bruce [Marine Biological Laboratory; Poole, Geoff [Eco-metrics; Valett, H. Maurice [Virginia Polytechnic Institute and State University (Virginia Tech); Webster, Jackson [Virginia Polytechnic Institute and State University (Virginia Tech); Arango, Clay [University of Notre Dame, IN; Beaulieu, Jake [University of Notre Dame, IN; Bernot, Melody [Murray State University; Burgin, Amy [Michigan State University, East Lansing; Crenshaw, Chelsea [University of New Mexico, Albuquerque; Helton, Ashley [University of Georgia, Athens, GA; Johnson, Laura [University of Notre Dame, IN; Niederlehner, Bobbie [Virginia Polytechnic Institute and State University (Virginia Tech); Potter, Jody [University of New Hampshire; Sheibley, Rich [Arizona State University; Thomas, Suzanne [Marine Biological Laboratory

    2009-01-01

    We measured denitrification rates using a field {sup 15}N-NO{sub 3}{sup -} tracer-addition approach in a large, cross-site study of nitrate uptake in reference, agricultural, and suburban-urban streams. We measured denitrification rates in 49 of 72 streams studied. Uptake length due to denitrification (S{sub Wden}) ranged from 89 m to 184 km (median of 9050 m) and there were no significant differences among regions or land-use categories, likely because of the wide range of conditions within each region and land use. N{sub 2} production rates far exceeded N{sub 2}O production rates in all streams. The fraction of total NO{sub 3}{sup -} removal from water due to denitrification ranged from 0.5% to 100% among streams (median of 16%), and was related to NH{sub 4}{sup +} concentration and ecosystem respiration rate (ER). Multivariate approaches showed that the most important factors controlling S{sub Wden} were specific discharge (discharge/width) and NO{sub 3}{sup -} concentration (positive effects), and ER and transient storage zones (negative effects). The relationship between areal denitrification rate (U{sub den}) and NO{sub 3}{sup -} concentration indicated a partial saturation effect. A power function with an exponent of 0.5 described this relationship better than a Michaelis-Menten equation. Although U{sub den} increased with increasing NO{sub 3}{sup -} concentration, the efficiency of NO{sub 3}{sup -} removal from water via denitrification declined, resulting in a smaller proportion of streamwater NO{sub 3}{sup -} load removed over a given length of stream. Regional differences in stream denitrification rates were small relative to the proximate factors of NO{sub 3}{sup -} concentration and ecosystem respiration rate, and land use was an important but indirect control on denitrification in streams, primarily via its effect on NO{sub 3}{sup -} concentration.

  4. Separating the contributions to 15N transverse relaxation in a fibronectin type III domain

    International Nuclear Information System (INIS)

    Meekhof, Alison E.; Freund, Stefan M.V.

    1999-01-01

    In proteins, dynamic mobility is an important feature of structure, stability, and biomolecular recognition. Uniquely sensitive to motion throughout the milli- to picosecond range, rates of transverse relaxation, R2, are commonly obtained for the characterization of chemical exchange, and the construction of motional models that attempt to separate overall and internal mobility. We have performed an in-depth study of transverse relaxation rates of backbone 15N nuclei in TNfn31-90, the third fibronectin type III domain from human tenascin. By combining the results of spin-echo (CPMG) and off-resonance T1ρ experiments, we present R2 rates at effective field strengths of 2 to 40 krad/s, obtaining a full spectrum of 16 independent R2 data points for most residues. Collecting such a large number of replicate measurements provides insight into intrinsic uncertainties. The median standard deviation in R2 for non-exchanging residues is 0.31, indicating that isolated measurements may not be sufficiently accurate for a precise interpretation of motional models. Chemical exchange events on a timescale of 570 μs were observed in a cluster of residues at the C terminus. Rates of exchange for five other residues were faster than the sampled range of frequencies and could not be determined. Averaged 'exchange free' transverse relaxation rates, R20, were used to calculate the diffusion tensor for rotational motion. Despite a highly asymmetric moment of inertia, the narrow angular dispersion of N-H vectors within the β sandwich proves insufficient to define deviations from isotropic rotation. Loop residues provide exclusive evidence for axially symmetric diffusion (Dpar/Dper=1.55)

  5. 1H and 15N NMR resonance assignments and secondary structure of titin type I domains

    Energy Technology Data Exchange (ETDEWEB)

    Muhle-Goll, Claudia; Nilges, Michael; Pastore, Annalisa [European Molecular Biology Laboratory (Germany)

    1997-01-15

    Titin/connect in is a giant muscle protein with a highly modular architecture consisting of multiple repeats of two sequence motifs, named type I and type II. Type I modules have been suggested to be intracellular members of the fibronectin type III (Fn3) domain family. Along the titin sequence they are exclusively present in the region of the molecule located in the sarcomere A-band. This region has been shown to interact with myosin and C-protein. One of the most noticeable features of type I modules is that they are particularly rich in semiconserved prolines, since these residues account for about 8% of their sequence. We have determined the secondary structure of a representative type I domain (A71) by 15N and 1HNMR. We show that the type I domains of titin have the Fn3 fold as proposed, consisting of a three- and a four-stranded {beta}-sheet. When the two sheets are placed on top of each other to form the {beta}-sandwich characteristic of the Fn3 fold, 8 out of 10 prolines are found on the same side of the molecule and form an exposed hydrophobic patch. This suggests that the semiconserved prolines might be relevant for the function of type I modules, providing a surface for binding to other A-band proteins. The secondary structure of A71 was structurally aligned to other extracellular Fn3 modules of known 3D structure. The alignment shows that titin type I modules have closest similarity to the first Fn3 domain of Drosophila neuroglian.

  6. {sup 15}N/{sup 14}N isotopic ratio and statistical analysis: an efficient way of linking seized Ecstasy tablets

    Energy Technology Data Exchange (ETDEWEB)

    Palhol, Fabien; Lamoureux, Catherine; Chabrillat, Martine; Naulet, Norbert

    2004-05-10

    In this study, the {sup 15}N/{sup 14}N isotopic ratios of 106 samples of 3,4-methylenedioxymethamphetamine (MDMA) extracted from Ecstasy tablets are presented. These ratios, measured using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS), show a large discrimination between samples with a range of {delta}{sup 15}N values between -17 and +19%o, depending on the precursors and the method used in clandestine laboratories. Thus, {delta}{sup 15}N values can be used in a statistical analysis carried out in order to link Ecstasy tablets prepared with the same precursors and synthetic pathway. The similarity index obtained after principal component analysis and hierarchical cluster analysis appears to be an efficient way to group tablets seized in different places.

  7. Addressing the overlap problem in the quantitative analysis of two dimensional NMR spectra: Application to 15N relaxation measurements

    International Nuclear Information System (INIS)

    Tugarinov, Vitali; Choy, W.-Y.; Kupce, Eriks; Kay, Lewis E.

    2004-01-01

    A quantitative analysis of 2D 1 H- 15 N spectra is often complicated by resonance overlap. Here a simple method is presented for resolving overlapped correlations by recording 2D projection planes from HNCO data sets. Applications are presented involving the measurement of 15 N T 1ρ relaxation rates in a high molecular weight protein, malate synthase G, and in a system that exchanges between folded and unfolded states, the drkN SH3 domain. By supplementing relaxation data recorded in the conventional way as a series of 2D 1 H- 15 N data sets with a series of a pair of projection planes the number of dynamics probes is increased significantly for both systems studied

  8. 15N/14N isotopic ratio and statistical analysis: an efficient way of linking seized Ecstasy tablets

    International Nuclear Information System (INIS)

    Palhol, Fabien; Lamoureux, Catherine; Chabrillat, Martine; Naulet, Norbert

    2004-01-01

    In this study, the 15 N/ 14 N isotopic ratios of 106 samples of 3,4-methylenedioxymethamphetamine (MDMA) extracted from Ecstasy tablets are presented. These ratios, measured using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS), show a large discrimination between samples with a range of δ 15 N values between -17 and +19%o, depending on the precursors and the method used in clandestine laboratories. Thus, δ 15 N values can be used in a statistical analysis carried out in order to link Ecstasy tablets prepared with the same precursors and synthetic pathway. The similarity index obtained after principal component analysis and hierarchical cluster analysis appears to be an efficient way to group tablets seized in different places

  9. Organic vs. conventional grassland management: do (15)N and (13)C isotopic signatures of hay and soil samples differ?

    Science.gov (United States)

    Klaus, Valentin H; Hölzel, Norbert; Prati, Daniel; Schmitt, Barbara; Schöning, Ingo; Schrumpf, Marion; Fischer, Markus; Kleinebecker, Till

    2013-01-01

    Distinguishing organic and conventional products is a major issue of food security and authenticity. Previous studies successfully used stable isotopes to separate organic and conventional products, but up to now, this approach was not tested for organic grassland hay and soil. Moreover, isotopic abundances could be a powerful tool to elucidate differences in ecosystem functioning and driving mechanisms of element cycling in organic and conventional management systems. Here, we studied the δ(15)N and δ(13)C isotopic composition of soil and hay samples of 21 organic and 34 conventional grasslands in two German regions. We also used Δδ(15)N (δ(15)N plant - δ(15)N soil) to characterize nitrogen dynamics. In order to detect temporal trends, isotopic abundances in organic grasslands were related to the time since certification. Furthermore, discriminant analysis was used to test whether the respective management type can be deduced from observed isotopic abundances. Isotopic analyses revealed no significant differences in δ(13)C in hay and δ(15)N in both soil and hay between management types, but showed that δ(13)C abundances were significantly lower in soil of organic compared to conventional grasslands. Δδ(15)N values implied that management types did not substantially differ in nitrogen cycling. Only δ(13)C in soil and hay showed significant negative relationships with the time since certification. Thus, our result suggest that organic grasslands suffered less from drought stress compared to conventional grasslands most likely due to a benefit of higher plant species richness, as previously shown by manipulative biodiversity experiments. Finally, it was possible to correctly classify about two third of the samples according to their management using isotopic abundances in soil and hay. However, as more than half of the organic samples were incorrectly classified, we infer that more research is needed to improve this approach before it can be efficiently

  10. Organic vs. conventional grassland management: do (15N and (13C isotopic signatures of hay and soil samples differ?

    Directory of Open Access Journals (Sweden)

    Valentin H Klaus

    Full Text Available Distinguishing organic and conventional products is a major issue of food security and authenticity. Previous studies successfully used stable isotopes to separate organic and conventional products, but up to now, this approach was not tested for organic grassland hay and soil. Moreover, isotopic abundances could be a powerful tool to elucidate differences in ecosystem functioning and driving mechanisms of element cycling in organic and conventional management systems. Here, we studied the δ(15N and δ(13C isotopic composition of soil and hay samples of 21 organic and 34 conventional grasslands in two German regions. We also used Δδ(15N (δ(15N plant - δ(15N soil to characterize nitrogen dynamics. In order to detect temporal trends, isotopic abundances in organic grasslands were related to the time since certification. Furthermore, discriminant analysis was used to test whether the respective management type can be deduced from observed isotopic abundances. Isotopic analyses revealed no significant differences in δ(13C in hay and δ(15N in both soil and hay between management types, but showed that δ(13C abundances were significantly lower in soil of organic compared to conventional grasslands. Δδ(15N values implied that management types did not substantially differ in nitrogen cycling. Only δ(13C in soil and hay showed significant negative relationships with the time since certification. Thus, our result suggest that organic grasslands suffered less from drought stress compared to conventional grasslands most likely due to a benefit of higher plant species richness, as previously shown by manipulative biodiversity experiments. Finally, it was possible to correctly classify about two third of the samples according to their management using isotopic abundances in soil and hay. However, as more than half of the organic samples were incorrectly classified, we infer that more research is needed to improve this approach before it can be

  11. Organic vs. Conventional Grassland Management: Do 15N and 13C Isotopic Signatures of Hay and Soil Samples Differ?

    Science.gov (United States)

    Klaus, Valentin H.; Hölzel, Norbert; Prati, Daniel; Schmitt, Barbara; Schöning, Ingo; Schrumpf, Marion; Fischer, Markus; Kleinebecker, Till

    2013-01-01

    Distinguishing organic and conventional products is a major issue of food security and authenticity. Previous studies successfully used stable isotopes to separate organic and conventional products, but up to now, this approach was not tested for organic grassland hay and soil. Moreover, isotopic abundances could be a powerful tool to elucidate differences in ecosystem functioning and driving mechanisms of element cycling in organic and conventional management systems. Here, we studied the δ15N and δ13C isotopic composition of soil and hay samples of 21 organic and 34 conventional grasslands in two German regions. We also used Δδ15N15N plant - δ15N soil) to characterize nitrogen dynamics. In order to detect temporal trends, isotopic abundances in organic grasslands were related to the time since certification. Furthermore, discriminant analysis was used to test whether the respective management type can be deduced from observed isotopic abundances. Isotopic analyses revealed no significant differences in δ13C in hay and δ15N in both soil and hay between management types, but showed that δ13C abundances were significantly lower in soil of organic compared to conventional grasslands. Δδ15N values implied that management types did not substantially differ in nitrogen cycling. Only δ13C in soil and hay showed significant negative relationships with the time since certification. Thus, our result suggest that organic grasslands suffered less from drought stress compared to conventional grasslands most likely due to a benefit of higher plant species richness, as previously shown by manipulative biodiversity experiments. Finally, it was possible to correctly classify about two third of the samples according to their management using isotopic abundances in soil and hay. However, as more than half of the organic samples were incorrectly classified, we infer that more research is needed to improve this approach before it can be efficiently used in practice

  12. Stellar Origin of 15N-rich Presolar SiC Grains of Type AB: Supernovae with Explosive Hydrogen Burning

    Science.gov (United States)

    Liu, Nan; Nittler, Larry R.; Pignatari, Marco; O'D. Alexander, Conel M.; Wang, Jianhua

    2017-06-01

    We report C, N, and Si isotopic data for 59 highly 13C-enriched presolar submicron- to micron-sized SiC grains from the Murchison meteorite, including eight putative nova grains (PNGs) and 29 15N-rich (14N/15N ≤ solar) AB grains, and their Mg-Al, S, and Ca-Ti isotope data when available. These 37 grains are enriched in 13C, 15N, and 26Al with the PNGs showing more extreme enhancements. The 15N-rich AB grains show systematically higher 26Al and 30Si excesses than the 14N-rich AB grains. Thus, we propose to divide the AB grains into groups 1 (14N/15N PNG and found 32S and/or 50Ti enhancements. Interestingly, one AB1 grain had the largest 32S and 50Ti excesses, strongly suggesting a neutron-capture nucleosynthetic origin of the 32S excess and thus the initial presence of radiogenic 32Si (t 1/2 = 153 years). More importantly, we found that the 15N and 26Al excesses of AB1 grains form a trend that extends to the region in the N-Al isotope plot occupied by C2 grains, strongly indicating a common stellar origin for both AB1 and C2 grains. Comparison of supernova models with the AB1 and C2 grain data indicates that these grains came from supernovae that experienced H ingestion into the He/C zones of their progenitors.

  13. 15N nitrogen-balance studies in patients with testicular feminization, their relatives, and in normal subjects

    International Nuclear Information System (INIS)

    Zachman, M.; Zagalak, M.; Voellmin, J.A.; Prader, A.

    1975-01-01

    Fourteen subjects (4 with testicular feminization, 2 mothers, 1 aunt and 1 father of these patients, 2 normal women, 2 normal men and 2 normal prepubertal boys) were given 0.1 to 0.2 g/kg of 50 percent 15 N-labeled NH 4 Cl before and after 6 daily injections of testosterone (T) 15 mg/m 2 ). In 24-hour urine specimens collected on the test days, 15 N was calculated from total N (Kjeldahl) and the percentage of 15 N (mass spectrometry or 15 N-analyzer Isocommerz). In all normal subjects, urinary 15 N-balance was influenced positively by T (+31.3 +- 8.4 percent), in prepubertal boys more (+43 to +66 percent) than in women (+20 to +30 percent) and men (+6 to +23). In testicular feminization, 15 N-balance not only failed to become more positive, but was even reduced (-24.7 +- 17.6 percent). The father of a patient had only a slight response (+7 percent) as one of the normal males, probably because of higher endogenous T-levels in adult males. One mother and the aunt had no response (-7.4 to + 1.5 percent). In the mother, the balance became slightly positive (+10 percent) on oral contraceptives. The other mother, who was on estrogen treatment prior to and during the test, had a positive but insufficient change of balance (+17 percent). It is concluded that this test allows detection of patients with testicular feminization and possibly also healthy female carriers. In these cases, estrogen treatment appears to positively influence the response to T

  14. Interpreting Precambrian δ15N: lessons from a new modern analogue, the volcanic crater lake Dziani Dzaha

    Science.gov (United States)

    Ader, M.; Cadeau, P.; Jezequel, D.; Chaduteau, C.; Fouilland, E.; Bernard, C.; Leboulanger, C.

    2017-12-01

    Precambrian nitrogen biogeochemistry models rely on δ15N signatures in sedimentary rocks, but some of the underlying assumptions still need to be more robustly established. Especially when measured δ15N values are above 3‰. Several processes have been proposed to explain these values: non-quantitative reduction of nitrate to N2O/N2 (denitrification), non-quantitative oxidation of ammonium to N2O/N2, or ammonia degassing to the atmosphere. The denitrification hypothesis implies oxygenation of part the water column, allowing nitrate to accumulate. The ammonium oxidation hypothesis implies a largely anoxic water column, where ammonium can accumulates, with limited oxygenation of surface waters. This hypothesis is currently lacking modern analogues to be supported. We propose here that the volcanic crater lake Dziani Dzaha (Mayotte, Indian Ocean) might be one of them, on the basis of several analogies including: permanently anoxic conditions at depth in spite of seasonal mixing; nitrate content below detection limit in the oxic surface waters; accumulation of ammonium at depth during the stratified season; primary productivity massively dominated by cyanobacteria. One aspect may restrict the analogy: the pH value of 9-9.5. In this lake, δ15N values of primary producers and ammonium range from 6 to 9‰ and are recorded with a positive offset in the sediments (9<δ15N<13‰). Because N-sources to the system present more negative δ15N values, such positive values can only be achieved if 14N-enriched N is lost from the lake. Although NH3 degassing might play a small role, the main pathway envisaged for this N-loss is NH4+ oxidation to N2O/N2. If confirmed, this would provide strong support for the hypothesis that positive δ15N values in Precambrian rocks may indicate dominantly anoxic oceans, devoid of nitrate, in which ammonium was partly oxidized to N2O/N2.

  15. Dynamics of the amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 5

    International Nuclear Information System (INIS)

    Gruhn, K.; Zander, R.; Kirchner, E.

    1987-01-01

    12 colostomized laying hens which received 15 N-labelled wheat over 4 days were butchered 12 h, 36 h, and 108 h (3 animals each) after the last 15 N application. The intake of 15 N exess ( 15 N') from the wheat amounted to 540 mg 15 N' during the application period. The 15 N' in the blood plasma decreased after the last 15 N' application from 0.76 atom-% to 0.55 atom-% after 108 h, the labelling of the corpuscular components at the same measuring points increased from 0.28 to 0.50 atom-% 15 N'. 96.6% of the plasma 15 N' and 93,8% of that in the corpuscles is precipitable in trichloroacetic acid. The atom-% 15 N' of histidine in the total blood remained unchanged in dependence on the butchering time. The 15 N amount in lysine and arginine and that in the non-basic amino acids decreased inconsiderably in the period between 12 h and 108 h after the last 15 N' wheat feeding. (author)

  16. Food resources of stream macroinvertebrates determined by natural-abundance stable C and N isotopes and a 15N tracer addition

    Science.gov (United States)

    Patrick J. Mulholland; Jennifer L. Tank; Diane M. Sanzone; Wilfrid M. Wollheim; Bruce J. Peterson; Jackson R. Webster; Judy L. Meyer

    2000-01-01

    Trophic relationships were examined using natural-abundance 13C and 15N analyses and a 15N-tracer addition experiment in Walker Branch, a 1st-order forested stream in eastern Tennessee. In the 15N-tracer addition experiment, we added 15NH4...

  17. /sup 15/N/sub 2/ incorporation and acetylene reduction by azospirillum isolated from rice roots and soils

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, D.N.; Charyulu, P.B.B.; Rajaramamohan Rao, V. (Central Rice Research Inst., Cuttack (India). Dept. of Soil Microbiology)

    1981-01-01

    Nitrogen fixation by strains of Azospirillum isolated from several rice soils and rice cultivars was investigated by /sup 15/N/sub 2/ incorporation and C/sub 2/H/sub 2/ reduction. C/sub 2/H/sub 2/ reducing ability markedly varied among the strains obtained from soils differing widely in their physico-chemical properties. Large variations in /sup 15/N/sub 2/ incorporation by Azospirillum isolated from the roots of several rice cultivars were also noticed. The present study reveals that rice cultivars harbour Azospirillum with differential N/sub 2/-fixing ability and that plant genotype is of importance for optimal associations.

  18. The fate of nitrogen in grain cropping systems: a meta-analysis of 15N field experiments.

    Science.gov (United States)

    Gardner, Jennifer B; Drinkwater, Laurie E

    2009-12-01

    Intensively managed grain farms are saturated with large inputs of nitrogen (N) fertilizer, leading to N losses and environmental degradation. Despite decades of research directed toward reducing N losses from agroecosystems, progress has been minimal, and the currently promoted best management practices are not necessarily the most effective. We investigated the fate of N additions to temperate grain agroecosystems using a meta-analysis of 217 field-scale studies that followed the stable isotope 15N in crops and soil. We compared management practices that alter inorganic fertilizer additions, such as application timing or reduced N fertilizer rates, to practices that re-couple the biogeochemical cycles of carbon (C) and N, such as organic N sources and diversified crop rotations, and analyzed the following response variables: 15N recovery in crops, total recovery of 15N in crops and soil, and crop yield. More of the literature (94%) emphasized crop recovery of 15N than total 15N recovery in crops and soil (58%), though total recovery is a more ecologically appropriate indicator for assessing N losses. Findings show wide differences in the ability of management practices to improve N use efficiency. Practices that aimed to increase crop uptake of commercial fertilizer had a lower impact on total 15N recovery (3-21% increase) than practices that re-coupled C and N cycling (30-42% increase). A majority of studies (66%) were only one growing season long, which poses a particular problem when organic N sources are used because crops recover N from these sources over several years. These short-term studies neglect significant ecological processes that occur over longer time scales. Field-scale mass balance calculations using the 15N data set show that, on average, 43 kg N x ha(-1) x yr(-1) was unaccounted for at the end of one growing season out of 114 kg N x ha(-1) x yr(-1), representing approximately 38% of the total 15N applied. This comprehensive assessment of

  19. Conversion electron Moessbauer spectroscopy and (p,αγ) nuclear reaction studies of 15N implanted steels

    International Nuclear Information System (INIS)

    Marest, G.; Skoutarides, C.; Barnavon, T.; Tousset, J.; Fayeulle, S.; Robelet, M.

    1982-11-01

    15 N implants (E=40 keV, PHI=2.10 17 ions.cm -2 ) into unalloyed iron and two steels type 100 C 6 and 42 CD4 at R.T. have been studied by nuclear analysis using the 15 N(p,αγ) 12 C reaction and by Moessbauer spectroscopy (CEMS). The relative amounts of nitrides have been followed during heat treatments at 250 0 C. The complementarity of these techniques allows to explain the evolution of the nitrogen content into implanted zone is controlled by the transformation kinetics of the nitrides and not by elementary nitrogen diffusion process

  20. Two standards - CSA-N288.1 and USNRC regulatory guides 1.109, 1.111 for chronic atmospheric releases from nuclear facilities - compared

    International Nuclear Information System (INIS)

    Peterson, S-R.

    1997-05-01

    Although the Canadian Standards Association's 'Guidelines for Calculating Derived Release Limits for Radioactive Material in Airborne and Liquid Effluents for Normal Operation of Nuclear Facilities', CSA-N288.1-M87 (CSA 1987) can be used to license CANDU (CANadian Deuterium Uranium) reactors sold off-shore, in practice purchasers may wish to use the United States Regulatory Guides (RG) 1.109 (United States Nuclear Regulatory Commission 1977a) and 1.111 (USNRC 1977b) to calculate doses from routine atmospheric releases to members of a critical group. When differences in dose predictions are found between the two standards, CSA-N288.1 comes under attack. This paper explains the differences between the two models. The two atmospheric dispersion models were compared for a ground level release and an elevated release such as from CANDU 6. For a ground level release, CSA's dilution factors were slightly more than half of RG's. For the elevated release, following recommendations in each guide, CSA's dilution coefficient is higher than RG's within 1000 m of the stack and only slightly lower farther away. All differences can be accounted for by different mathematical formulations and assumptions about height at which wind speed is measured. Ingestion, inhalation, immersion and external doses predicted by the two models were compared for unit release (Bq s -1 ) and for realistic source terms of a suite of 33 radionuclides commonly released from both CANDUs and Pressurized Water Reactors (PWRs). To demonstrate real differences in the models, ingestion doses for the two models were compared using the CSA diet in both models and CSA predictions were recalculated to account for decay which occurs between harvest and ingestion in RG. Once all assumptions are equalized, there is very little difference in dose predictions of the two models that cannot be explained by different parameter values. Both models have outdated dose conversion factors, and the use of improved numbers will

  1. Effects of drop sets with resistance training on increases in muscle CSA, strength, and endurance: a pilot study.

    Science.gov (United States)

    Ozaki, Hayao; Kubota, Atsushi; Natsume, Toshiharu; Loenneke, Jeremy P; Abe, Takashi; Machida, Shuichi; Naito, Hisashi

    2018-03-01

    To investigate the effects of a single high-load (80% of one repetition maximum [1RM]) set with additional drop sets descending to a low-load (30% 1RM) without recovery intervals on muscle strength, endurance, and size in untrained young men. Nine untrained young men performed dumbbell curls to concentric failure 2-3 days per week for 8 weeks. Each arm was randomly assigned to one of the following three conditions: 3 sets of high-load (HL, 80% 1RM) resistance exercise, 3 sets of low-load [LL, 30% 1RM] resistance exercise, and a single high-load (SDS) set with additional drop sets descending to a low-load. The mean training time per session, including recovery intervals, was lowest in the SDS condition. Elbow flexor muscle cross-sectional area (CSA) increased similarly in all three conditions. Maximum isometric and 1RM strength of the elbow flexors increased from pre to post only in the HL and SDS conditions. Muscular endurance measured by maximum repetitions at 30% 1RM increased only in the LL and SDS conditions. A SDS resistance training program can simultaneously increase muscle CSA, strength, and endurance in untrained young men, even with lower training time compared to typical resistance exercise protocols using only high- or low-loads.

  2. Refining Soil Test Calibration and Nitrogen Recommendation in Corn through 15N Isotope Tracer Technique

    International Nuclear Information System (INIS)

    Rallos, Roland V.

    2015-01-01

    Soil test serve as a baseline to efficiently manage the fertilizer inputs and determine excess nutrients that may cause adverse impact to human health and the environment. The ever increasing fertilizer prices and application inefficiency raised concerns to re-evaluate and redesigned the current crop cultural management to increase its efficiency and productivity. Additionally, with the intensification of farming methods, corn varietal improvement, soil degradations, climate change among many others, the earlier fertilizer recommendations may not be sufficient enough to match with the crop’s fertilizer requirements. The use of 15N isotope tracer techniques in nutrient management research implies important benefits than any existing conventional methodologies. This technology provides enormous advantages because it permits a direct quantitative measurement of the crop nutrient utilization under the influence of varied factors of the environment. Hence, this technique was used to understand N dynamics and fertilizer N-use efficiency (FNUE) in corn grown under different soil fertility levels during wet and dry season productions. This allows us to follow the fate and accurately quantify the contribution of different N pools to the crops N nutrition. Results showed that the fertilizer rates for optimum corn yield under low soil N was observed at 180 kg N ha-1 during dry season while 90 kg N ha-1 during wet season production. While for medium and high N soil, the optimum production yield was noted in 45 kg N ha-1 both in dry and wet season productions. Economic optimum nitrogen recommendations (EONR) were also calculated following the quadratic crop response model. In all cases, EONR for dry season productions are much higher compared to wet season production. Generally, high chlorophyll content was observed at higher fertilizer levels. In addition, more than half of the plant N was taken directly from the added fertilizer during the early stage (30-60 days after

  3. Replacing mass spectrometer with optical spectrometer for measuring 15N abundance in detecting the helicobacter pylori infection

    International Nuclear Information System (INIS)

    Zhu Yayi, Shen Yang; Wu Jicong

    1996-01-01

    Since the discovery of HP (Helicobacter pylori) and its close association with gastritis and peptic ulceration, it has been important to establish a practical method for conveniently testing HP infection. Because of the strong urease activity of HP, the urea administered orally is broken down into NH 3 and CO 2 by the HP urease in the patient's stomach. Then the NH 3 is absorbed by the blood and excreted in the urine. The HP infection can be detected with 15 N - tracing method, 15 NH 4 + excretion test, using 15 N urea as a tracer compound. Performing on the detection with a optical spectrometer made by us for measuring the 15 N - abundance in the urine is reported. A group of 24 patients was detected. The results are accurate and similar to microbiological tests. The optical spectrometer is cheaper, simpler and more convenient to operate than a mass spectrometer in measuring 15 N abundance. Using the optical instrument, the 15 NH 4 + excretion test could be widely used in hospitals. (author). 6 refs., 1 tab

  4. Long-term 15N-nitrogen retention in tidal freshwater marsh sediment: Elucidating the microbial contribution

    NARCIS (Netherlands)

    Gribsholt, B.; Veuger, B.; Tramper, A.; Middelburg, J.J.; Boschker, H.T.S.

    2009-01-01

    The long-term retention of nitrogen in sediment of a tidal freshwater marsh in the Scheldt estuary (Belgium) was investigated by an in situ 15N-labeling experiment. Sediment of an unvegetated creek bank and sediment vegetated by common reed (Phragmites australis) were labeled with 15NN-enriched NH4+

  5. Variation in hair δ13C and δ15N values in long-tailed macaques (Macaca fascicularis) from Singapore

    Science.gov (United States)

    Schillaci, Michael A.; Castellini, J. Margaret; Stricker, Craig A.; Jones-Engel, Lisa; Lee, Benjamin P.Y.-H.

    2014-01-01

    Much of the primatology literature on stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) has focused on African and New World species, with comparatively little research published on Asian primates. Here we present hair δ13C and δ15N isotope values for a sample of 33 long-tailed macaques from Singapore. We evaluate the suggestion by a previous researcher that forest degradation and biodiversity loss in Singapore have led to a decline in macaque trophic level. The results of our analysis indicated significant spatial variability in δ13C but not δ15N. The range of variation in δ13C was consistent with a diet based on C3 resources, with one group exhibiting low values consistent with a closed canopy environment. Relative to other macaque species from Europe and Asia, the macaques from Singapore exhibited a low mean δ13C value but mid-range mean δ15N value. Previous research suggesting a decline in macaque trophic level is not supported by the results of our study.

  6. Fertilizer nitrogen prescription for cotton by 15N recovery method under integrated nutrient management using soil test crop response function

    International Nuclear Information System (INIS)

    Arulmozhiselvan, K.; Govindaswamy, M.; Chellamuthu, S.

    2007-01-01

    Fertilizer efficiency is a vital parameter in prescription functions to compute fertilizer requirements of crops for achieving a specific yield target. In Soil Test Crop Response (STCR) function, nitrogen fertilizer efficiency is calculated by Apparent N Recovery (ANR) method, which includes the effect of added N interaction (ANI) on soil N reserves. In order to exclude soil effect and refine STCR function, the real efficiency of fertilizer N was estimated by 15 N recovery method. By fitting 15 N recovery in the function, the fertilizer N required for a specific yield target of cotton was estimated. The estimated N requirement by 15 N recovery method was lesser than ANR method when available soil N relatively increased. The approach also fine-tuned the N contributing efficiency of soil, farmyard manure and Azospirillum under Integrated Nutrient Management (INM). For achieving 25 q of seed cotton yield in a soil having 220 kg of available N ha -1 , the predicted N requirement was 159 kg ha -1 under ANR method, whereas in 15 N recovery method fertilizer N to be applied was 138 kg ha -1 with urea alone and 79 kg ha -1 with urea + FYM + Azospirillum. (author)

  7. Anthropogenic nitrogen input traced by means of δ 15N values in macroalgae: Results from in-situ incubation experiments

    International Nuclear Information System (INIS)

    Deutsch, Barbara; Voss, Maren

    2006-01-01

    The macroalgae species Fucus vesiculosus (Phaeophyta), Polysiphonia sp., and Ceramium rubrum (Rhodophyta) originally grown at an unpolluted brackish site of the southern Baltic Sea were incubated for 10 and 14 days at 12 stations along a salinity gradient in a highly polluted estuary. We have expected an adaptation of the initially low δ 15 N values to the higher ones within the incubation period. In addition to the macroalgae the δ 15 N values of NO 3 - were measured to evaluate fractionation processes of the source nitrate. Inside the estuary, δ 15 N-NO 3 - values were 6.2-9.7 per mille , indicating anthropogenic nitrogen sources. The red macroalgae adequately reflected the nitrate isotope values in the surrounding waters, whereas for F. vesiculosus the results were not that clear. The reasons were assumed to be higher initial δ 15 N values of F. vesiculosus and presumably a too slow nitrogen uptake and growth rate. The method of macroalgae incubations seems suitable as a simple monitoring to study the influence of anthropogenic nitrogen loading in an estuarine environment

  8. Litterfall 15N abundance indicates declining soil nitrogen availability in a free-air CO2 enrichment experiment.

    Science.gov (United States)

    Garten, Charles T; Iversen, Colleen M; Norby, Richard J

    2011-01-01

    Forest productivity increases in response to carbon dioxide (CO2) enrichment of the atmosphere. However, in nitrogen-limited ecosystems, increased productivity may cause a decline in soil nitrogen (N) availability and induce a negative feedback on further enhancement of forest production. In a free-air CO2 enrichment (FACE) experiment, the response of sweetgum (Liquidambar styraciflua L.) productivity to elevated CO2 concentrations [CO2] has declined over time, but documenting an associated change in soil N availability has been difficult. Here we assess the time history of soil N availability through analysis of natural 15N abundance in archived samples of freshly fallen leaf litterfall. Litterfall delta15N declined from 1998 to 2005, and the rate of decline was significantly faster in elevated [CO2]. Declining leaf litterfall delta15N is indicative of a tighter ecosystem N cycle and more limited soil N availability. By integrating N availability over time and throughout the soil profile, temporal dynamics in leaf litterfall delta15N provide a powerful tool for documenting changes in N availability and the critical feedbacks between C and N cycles that will control forest response to elevated atmospheric CO2 concentrations.

  9. The structural topology of wild-type phospholamban in oriented lipid bilayers using 15N solid-state NMR spectroscopy.

    Science.gov (United States)

    Abu-Baker, Shadi; Lu, Jun-Xia; Chu, Shidong; Shetty, Kiran K; Gor'kov, Peter L; Lorigan, Gary A

    2007-11-01

    For the first time, 15N solid-state NMR experiments were conducted on wild-type phospholamban (WT-PLB) embedded inside mechanically oriented phospholipid bilayers to investigate the topology of its cytoplasmic and transmembrane domains. 15N solid-state NMR spectra of site-specific 15N-labeled WT-PLB indicate that the transmembrane domain has a tilt angle of 13 degrees+/-6 degrees with respect to the POPC (1-palmitoyl-2-oleoyl-sn-glycero-phosphocholine) bilayer normal and that the cytoplasmic domain of WT-PLB lies on the surface of the phospholipid bilayers. Comparable results were obtained from site-specific 15N-labeled WT-PLB embedded inside DOPC/DOPE (1,2-dioleoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine) mechanically oriented phospholipids' bilayers. The new NMR data support a pinwheel geometry of WT-PLB, but disagree with a bellflower structure in micelles, and indicate that the orientation of the cytoplasmic domain of the WT-PLB is similar to that reported for the monomeric AFA-PLB mutant.

  10. Increasing plant use of organic nitrogen with elevation is reflected in nitrogen uptake rates and ecosystem delta15N.

    Science.gov (United States)

    Averill, Colin; Finzi, Adrien

    2011-04-01

    It is hypothesized that decreasing mean annual temperature and rates of nitrogen (N) cycling causes plants to switch from inorganic to organic forms of N as the primary mode of N nutrition. To test this hypothesis, we conducted field experiments and collected natural-abundance delta15N signatures of foliage, soils, and ectomycorrhizal sporocarps along a steep elevation-climate gradient in the White Mountains, New Hampshire, USA. Here we show that with increasing elevation organic forms of N became the dominant source of N taken up by hardwood and coniferous tree species based on dual-labeled glycine uptake analysis, an important confirmation of an emerging theory for the biogeochemistry of the N cycle. Variation in natural abundance foliar delta15N with elevation was also consistent with increasing organic N uptake, though a simple, mass balance model demonstrated that the uptake of delta15N depleted inorganic N, rather than fractionation upon transfer of N from mycorrhizal fungi, best explains variations in foliar delta15N with elevation.

  11. Use of 15N Natural Abundance and N Species Concentrations to Assess N-Cycling in Constructed and Natural Coastal

    International Nuclear Information System (INIS)

    Aelion, W.C.M.; Engle, M.R.; Aelion, W.C.M.; Ma, H.

    2010-01-01

    Natural abundance of N stable isotopes used in combination with concentrations may be useful indicators of N-cycling in wetlands. Concentrations and 15 N signatures of NO 3 -, NH 4 and sediment organic nitrogen (SON) were measured in two impacted coastal golf course retention ponds and two natural marshes. Limited NO 3 was detected in natural site surface water or pore water, but both isotopic signature and concentrations of NO 3 - in surface water of impacted sites indicated anthropogenic inputs. In natural sites, NH 4 concentrations were greatest in deeper pore water and least in surface water, suggesting diffusion predominates. The natural sites had greater % SON, and 15 N indicated that the natural sites also had greater NH 4 + released from SON mineralization than impacted sites. In NO 3 --limited systems, neither concentrations nor 15 N natural abundance was able to provide information on N-cycling, while processes associated with NH 4 + were better elucidated by using both concentrations and 15 N natural abundance

  12. Secondary structure and (1)H, (13)C, (15)N resonance assignments of the endosomal sorting protein sorting nexin 3

    OpenAIRE

    Overduin Michael; Rajesh Sandya; Gruenberg Jean; Lenoir Marc

    2015-01-01

    Sorting nexin 3 (SNX3) belongs to a sub family of sorting nexins that primarily contain a single Phox homology domain capable of binding phosphoinositides and membranes. We report the complete (1)H (13)C and (15)N resonance assignments of the full length human SNX3 protein and identification of its secondary structure elements revealing a canonical fold and unstructured termini.

  13. Secondary structure and (1)H, (13)C, (15)N resonance assignments of the endosomal sorting protein sorting nexin 3.

    Science.gov (United States)

    Overduin, Michael; Rajesh, Sandya; Gruenberg, Jean; Lenoir, Marc

    2015-10-01

    Sorting nexin 3 (SNX3) belongs to a sub-family of sorting nexins that primarily contain a single Phox homology domain capable of binding phosphoinositides and membranes. We report the complete (1)H, (13)C and (15)N resonance assignments of the full-length human SNX3 protein and identification of its secondary structure elements, revealing a canonical fold and unstructured termini.

  14. The influence of fish cage culture on δ13C and δ15N of filter-feeding Bivalvia (Mollusca

    Directory of Open Access Journals (Sweden)

    E. Benedito

    Full Text Available The objective of this study was to evaluate the effect of Oreochromis niloticus cage culture promoted variations in the δ13C and δ15N in Corbicula fluminea (Mollusca; Bivalvia and in the sediment of an aquatic food web. Samples were taken before and after net cage installation in the Rosana Reservoir (Paranapanema River, PR-SP. Samples of specimens of the bivalve filterer C. fluminea and samples of sediment were collected using a modified Petersen grab. All samples were dried in an oven (60 °C for 72 hours, macerated to obtain homogenous fine powders and sent for carbon (δ13C and nitrogen (δ15N isotopic value analysis in a mass spectrometer. There were significant differences in the δ13C and δ15N values of the invertebrate C. fluminea between the beginning and the end of the experiment. There were no differences between the δ13C and δ15N values of sediment. These results indicate that the installation of fish cage culture promoted impacts in the isotopic composition of the aquatic food web organisms, which could exert influence over the native species and the ecosystem.

  15. Contrasting food web linkages for the grazing pathway in 3 temperate forested streams using {sup 15}N as a tracer

    Energy Technology Data Exchange (ETDEWEB)

    Tank, J.L.; Mulholland, P.J.; Meyer, J.L.; Bowden, W.B.; Webster, J.R.; Peterson, B.J.

    1998-11-01

    Nitrogen is a critical element controlling the productivity and dynamics of stream ecosystems and many streams are limited by the supply of biologically available nitrogen. The authors are learning more about the fate of inorganic nitrogen entering streams through {sup 15}N tracer additions. The Lotic Intersite Nitrogen Experiment (LINX) is studying the uptake, cycling, and fate of {sup 15}N-NH{sub 4} in the stream food web of 10 streams draining different biomes. Using the {sup 15}N tracer method and data from 3 sites in the study, the authors can differentiate patterns in the cycling of nitrogen through the grazing pathway (N from the epilithon to grazing macroinvertebrates) for 3 temperate forested streams. Here, they quantify the relationship between the dominant grazer and its proposed food resource, the epilithon, by comparing {sup 15}N levels of grazers with those of the epilithon, as well as the biomass, nitrogen content, and chlorophyll a standing stocks of the epilithon in 3 streams.

  16. Isotope Ratio Mass Spectrometry Monitoring of Nitrogen Volatilization from Beef Cattle Feces and 15N-Labeled Synthetic Urine

    Directory of Open Access Journals (Sweden)

    Ferouz Y. Ayadi

    2015-05-01

    Full Text Available A 15-day bench-scale manure storage experiment with a slurry mixture comprising beef cattle feces and synthetic urine with 15N-labeled urea was conducted to evaluate the source of volatilized ammonia nitrogen (NH3-N. Beef cattle feces was mixed daily in a 1:2.2 mass ratio with 15N-labeled urine and added for four consecutive days to 2-L storage containers and then left undisturbed for eleven days. Isotope ratio mass spectrometry was used to determine the origin of aerial NH3-N losses from the relative isotopic abundance of N in the 15N-labeled slurry mixture. On average 84% of total NH3-N losses originated from the urine portion and were highest during the first two to four days, when fresh material was added. After fresh material addition ceased, daily NH3-N emission from the urine decreased gradually, whereas emission from the feces remained relatively constant. Calculations showed that over 34% of aerial N was not captured, suggesting that other N gas emission is significant from slurry mixtures. Likely all uncaptured N losses were from urinary urea. The study verified the applicability of 15N-labeled synthetic urine for beef slurry mixtures. However, the results suggest further research to explain and model the NH3 and N release from fecal material is warranted and to determine the identity of the uncaptured N losses.

  17. Simultaneous determination of 14N and 15N isotopes in opium by proton induced γ-ray emission technique

    International Nuclear Information System (INIS)

    Pritty Rao; Reddy, G.L.N.; Vikram Kumar, S.; Ramana, J.V.; Raju, V.S.; Sanjiv Kumar

    2012-01-01

    The paper describes the simultaneous determination of 14 N and 15 N isotopes in opium by proton induced γ-ray emission (PIGE) technique. The isotopic ratio of 14 N and 15 N is a useful parameter for assigning provenance of (seized) illicit drugs. The measurement, non-destructive in nature, is performed on pellets made up of opium powders and is based on the prompt detection of 2.313 and 4.4 MeV γ-rays emanating from 14 N(p,p'γ) 14 N and 15 N(p,αγ) 12 C nuclear reactions respectively, induced simultaneously by 3.6-3.8 MeV proton beam. Positive as well as negative deviations from the natural isotopic abundance (99.63:0.37) were observed in the samples. The precision of the measurements is about 4%. The methodology provides an easy and rapid approach to determine the isotopic ratio of 14 N and 15 N and has been used for the first time in the analysis of opium. (author)

  18. Patterns and implications of plant-soil δ13C and δ15N values in African savanna ecosystems

    Science.gov (United States)

    Wang, Lixin; D'Odorico, Paolo; Ries, Lydia; Macko, Stephen A.

    2010-01-01

    Southern African savannas are mixed plant communities where C 3 trees co-exist with C 4 grasses. Here foliar δ15N and δ13C were used as indicators of nitrogen uptake and of water use efficiency to investigate the effect of the rainfall regime on the use of nitrogen and water by herbaceous and woody plants in both dry and wet seasons. Foliar δ15N increased as aridity rose for both C 3 and C 4 plants for both seasons, although the magnitude of the increase was different for C 3 and C 4 plants and for two seasons. Soil δ15N also significantly increased with aridity. Foliar δ13C increased with aridity for C 3 plants in the wet season but not in the dry season, whereas in C 4 plants the relationship was more complex and non-linear. The consistently higher foliar δ15N for C 3 plants suggests that C 4 plants may be a superior competitor for nitrogen. The different foliar δ13C relationships with rainfall may indicate that the C 3 plants have an advantage when competing for water resources. The differences in water and nitrogen use likely collectively contribute to the tree-grass coexistence in savannas. Such differences facilitate interpretations of palaeo-vegetation composition variations and help predictions of vegetation composition changes under future climatic scenarios.

  19. Nitrogen dynamics in stream wood samples incubated with [14C]lignocellulose and potassium[15N]nitrate

    International Nuclear Information System (INIS)

    Aumen, N.G.; Bottomley, P.J.; Gregory, S.V.

    1985-01-01

    Surface wood samples obtained from a Douglas fir log incubated in vitro with [ 14 C]lignocellulose in a defined mineral salts medium supplemented with 10 mg of N liter -1 of 15 N-labeled NO 3 - (50 atom % 15 N). Evolution of 14 CO 2 , distribution and isotopic dilution of 15 N, filtrate N concentrations, and the rates of denitrification, N 2 fixation, and respiration were measured at 6, 12, and 18 days of incubation. The organic N content of the lignocellulose-wood sample mixture had increased from 132 μg of N to a maximum of 231 μg of N per treatment after 6 days of incubation. Rates of [ 14 C]lignocellulose decomposition were greatest during the first 6 days and then began to decline over the remaining 12 days. Total CO 2 evolution was also highest at day 6 and declined steadily over the remaining duration of the incubation. Filtrate NH 4 + -N increased from background levels to a final value of 57 μg of N per treatment. Filtrate NO 3 - N completely disappeared by day 6, and organic N showed a slight decline between days 12 and 18. The majority of the 15 N that could be recovered appeared in the particulate organic fraction by day 6 (41 μg of N), and the filtrate NH 4 + N fraction contained 11 μg of 15 N by day 18. The 15 N enrichment values of the filtrate NH 4 + and the inorganic N associated with the particulate fraction had increased to approximately 20 atom % 15 N by 18 days of incubation, whereas the particulate organic fraction reached its highest enrichment by day 6. Measurements of N 2 fixation and denitrification indicated an insignificant gain or loss of N from the experimental system by these processes. The data show that woody debris in stream ecosystems might function as a rapid and efficient sink for exogenous N, resulting in stimulation of wood decomposition and subsequent activation of other N cycling processes

  20. Comparative effects of application of coated and non-coated urea in clayey and sandy paddy soil microcosms examined by the 15N tracer technique. 2. Effects on soil microbial biomass N and microbial 15N immobilization

    International Nuclear Information System (INIS)

    Acquaye, Solomon; Inubushi, Kazuyuki

    2004-01-01

    Nitrogen fertilizer and soil types exert an impact on plant and soil microbial biomass (SMB). A 15 N tracer experiment was conducted to compare the effects of the application of controlled-release coated urea (CRCU) and urea on SMB in gley (clayey) and sandy paddy soils. The fertilizers were applied at the rate of 8 g N m -2 for CRCU as deep-side placement and 10 g N m -2 for urea mixed into soil or applied into floodwater. The soil type and soil layer (surface: few millimeter depth of surface soil to include benthic algae; subsurface: 1 to 20 cm depth), but not the fertilizer type, affected the amount of microbial biomass N (B N ). On an area basis, subsurface soil layers contained about 2-3 times the amount of B N in the surface layers. The seasonal average B N amount i.e. at 1 to 20 cm depth, in the gley soil was 1.67 g N m -2 , compared to 1.20 g N m -2 for the sandy soil. The proportion of B N in total soil N was significantly influenced by the soil type and soil layer, and was higher for the surface layers of both soils and subsurface layer of the sandy soil than for the subsurface layer of gley soil. Soil type, soil layer, and fertilizer type significantly influenced the amount of microbial biomass 15 N (B 15N ). Unlike B N , the amount of B 15N was significantly higher in the surface (11.9-177.3 mg N m -2 ) than in the subsurface soil layers (4.8-83.6 mg N m -2 ), especially with urea application between 60 and 120 DAT (days after transplanting). At 30 DAT, the subsurface layer of the sandy soil showed a higher B 15N (218 mg N m -2 ) amount than the surface layer (133.4 mg N m -2 ). Sandy soil (4.8-218 mg N m -2 ) and urea (6.2-218 mg N m -2 ) induced a larger increase of the amount of B 15 N than the gley soil (6.2-83.6 mg N m -2 ) and CRCU (4.8-40 mg Nm -2 ). Again, the sandy soil, surface soil layers, and urea induced a higher proportion (%) of B 15N in B N than the gley soil, subsurface soil layers, and CRCU, respectively. The soil type affected B N

  1. A 15N stable isotope semen label to detect mating in the malaria mosquito Anopheles arabiensis Patton

    Directory of Open Access Journals (Sweden)

    Gludovacz Doris

    2008-07-01

    Full Text Available Abstract In previous studies it was determined that the stable isotope 13-carbon can be used as a semen label to detect mating events in the malaria mosquito Anopheles arabiensis. In this paper we describe the use of an additional stable isotope, 15-nitrogen (15N, for that same purpose. Both stable isotopes can be analysed simultaneously in a mass spectrometer, offering the possibility to detect both labels in one sample in order to study complex and difficult-to-detect mating events, such as multiple mating. 15N-glycine was added to larval rearing water and the target enrichment was 5 atom% 15N. Males from these trays were mated with unlabelled virgin females, and spiked spermathecae were analysed for isotopic composition after mating using mass spectrometry. Results showed that spermathecae positive for semen could be distinguished from uninseminated or control samples using the raw δ15N‰ values. The label persisted in spermathecae for up to 5 days after insemination, and males aged 10 days transferred similar amounts of label as males aged 4 days. There were no negative effects of the label on larval survival and male longevity. Enrichment of teneral mosquitoes after emergence was 4.85 ± 0.10 atom% 15N. A threshold value defined as 3 standard deviations above the mean of virgin (i.e. uninseminated spermathecae samples was successful in classifying a large proportion of samples correctly (i.e. on average 95%. We conclude that alongside 13C, 15N can be used to detect mating in Anopheles and the suitability of both labels is briefly discussed.

  2. A 15N study on dietary urea utility in young pigs fed with a low protein diet

    International Nuclear Information System (INIS)

    Niiyama, Masayoshi; Kagota, Katsumoto; Iwase, Toshio; Namioka, Shigeo

    1978-01-01

    To investigate effect of a low protein diet on urea utilization, a tracer study was conducted with 15 N-urea on pigs fed a low protein diet (DCP 5.7%) with 2% urea (group B), and on pigs fed and optimal protein diet (DCP 13.3%) with 2% urea (group A). 15 N was incorporated into protein of liver, serum and muscle, which were obtained 8 days after the last administration of 15 N-urea. The 15 N incorporation rate into the tissue protein tended to be higher in group B than in group A. Approximately 70% of 15 N, however, was excreted into urine within 48 hours in group B. A comparison was made on growth and urea level in blood and urine to evaluate efficacy of the administered urea on growth between group B pigs and pigs fed the same low protein diet without urea supplementation (group C). Since group B pigs always maintained a higher level of blood urea, they were considered to have had more ammonia nitrogen which was available for protein synthesis than group C animals. A similar amount of urea to ingested dose, however, was excessively eliminated in urine. The increased ammonia nitrogen by urea ingestion may be excreted in form of urinary urea in group B pigs. There was no difference in growth between group B and group C animals; therefore, poor efficacy of administered urea on growth may have resulted not only from its loss into urine in early stage after ingestion, but also to poor utility of ammonia for protein synthesis. (author)

  3. Retrospective characterization of ontogenetic shifts in killer whale diets via δ13C and δ15N analysis of teeth

    Science.gov (United States)

    Newsome, Seth D.; Etnier, Michael A.; Monson, Daniel H.; Fogel, Marilyn L.

    2009-01-01

    Metabolically inert, accretionary structures such as the dentin growth layers in teeth provide a life history record of individual diet with near-annual resolution. We constructed ontogenetic δ13C and δ15N profiles by analyzing tooth dentin growth layers from 13 individual killer whales Orcinus orca collected in the eastern northeast Pacific Ocean between 1961 and 2003. The individuals sampled were 6 to 52 yr old, representing 2 ecotypes—resident and transient—collected across ~25° of latitude. The average isotopic values of transient individuals (n = 10) are consistent with a reliance on mammalian prey, while the average isotopic values of residents (n = 3) are consistent with piscivory. Regardless of ecotype, most individuals show a decrease in δ15N values of ~2.5‰ through the first 3 yr of life, roughly equivalent to a decrease of one trophic level. We interpret this as evidence of gradual weaning, after which, ontogenetic shifts in isotopic values are highly variable. A few individuals (n = 2) maintained relatively stable δ15N and δ13C values throughout the remainder of their lives, whereas δ15N values of most (n = 11) increased by ~1.5‰, suggestive of an ontogenetic increase in trophic level. Significant differences in mean δ13C and δ15N values among transients collected off California suggest that individuality in prey preferences may be prevalent within this ecotype. Our approach provides retrospective individual life history and dietary information that cannot be obtained through traditional field observations of free-ranging and elusive species such as killer whales, including unique historic ecological information that pre-dates modern studies. By providing insights into individual diet composition, stable isotope analysis of teeth and/or bones may be the only means of evaluating a number of hypothesized historical dietary shifts in killer whales of the northeast Pacific Ocean

  4. Estimation of the endogenous N proportions in ileal digesta and faeces in 15N-labelled pigs

    International Nuclear Information System (INIS)

    Simon, O.; Bergner, H.

    1987-01-01

    4 castrated male pigs 40 kg fitted with simple 'T' cannulas in the terminal ileum were given 15 N-labelled ammonium salts, added to a low protein diet, for 6 days. Excretion of 15 N in urine and feces was monitored daily throughout the labelling and subsequent experimental periods. During the experimental period the pigs were given a diet based on wheat and fish meal, supplemented with varying levels of partially hydrolyzed straw meal to give crude fiber contents ranging from 40 to 132 g/kg. After adaptation to the particular levels of straw meal, feces and ileal digesta were collected during successive 24 h periods. N digestibility values were determined by the chromium oxide ratio method. The retention of 15 N-labelled non-specific N was 0.46 of the dose given. The validity of using urine values as a measure of 15 N abundance in endogenous N was demonstrated by the similarity of 15 N abundance in urine immediately before slaughter at the end of the experiment and in the digestive secretory organs thereafter. The average amount of endogenous N passing the terminal ileum was 3.4 g/day or 0.30-0.50 of total ileal N flow. This was not affected by dietary fiber level. The proportion of fecal N which was of endogenous origin was similar to that in ileal digesta, suggesting similar utilization of endogenous and residual dietary N by hindgut bacteria. Half the endogenous N entering the large intestine was reabsorbed there. Increasing dietary crude fiber from 40 to 132 g/kg increased fecal endogenous N excretion from 1.3 to 2.0 g/animal and day. (author)

  5. Production of 15N-Labelled Liquid Organic Fertilisers Based on Manure and Crop Residue for Use in Fertigation Studies.

    Science.gov (United States)

    Martínez-Alcántara, Belén; Martínez-Cuenca, Mary-Rus; Fernández, Carlos; Legaz, Francisco; Quiñones, Ana

    2016-01-01

    Large quantities of crop residue and animal manure from agricultural and livestock activities are annually produced worldwide. With proper management, these residues are potentially valuable sources of plant nutrients, mainly N. Recycling such subproducts in sustainably-based agricultural systems can minimise the use of mineral fertilisers, and hence reduce the potential risk of surface and groundwater pollution. Therefore, the purpose of this study was to obtain (small scale) two liquid labelled-organic fertilisers, an animal- and a vegetal-based organic (AO and VO, respectively) fertiliser, to be used as organic N sources in subsequent fertigation studies. Forage maize (Zea mays L.) grown under 15N-labelled fertiliser supply was used as raw material for VO fertiliser production, and also as 15N-labelled sheep feed to obtain 15N-labelled manure. The labelled faeces fraction was used as raw material for the AO fertiliser. The VO fertiliser was obtained after an acidic and an enzyme-driven hydrolysis. The AO fertiliser was obtained after acidic hydrolysis. The VO liquid fertiliser presented an N concentration of 330 mg·L-1, 85% of total N was organic, while ammonium and nitrate N accounted for 55% and 45% of the mineral nitrogen fraction, respectively. This fertiliser also exhibited high K, Ca and S concentrations and notable values for the remaining macro- and micronutrients. The AO liquid fertiliser had a similar total N concentration (496 mg·L-1, 82% of total N in an organic form) to that of VO, but its mineral N fraction significantly differed, which came in a predominantly (95%) ammonia form. It also had a high content of N, P, K and other macronutrients, and sufficient Fe, Zn, Mn, Cu and B levels, which suggests its suitability as a potential fertiliser. The percentage of 15N enrichment in both VO and AO liquid fertilisers exceeded 2% 15N atom excess, which enabled their use in subsequent assays run to assess nitrogen uptake efficiency.

  6. Bradyrhizobium strain and the {sup 15}N natural abundance quantification of biological N{sub 2} fixation in soybean

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Ana Paula [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacases, RJ (Brazil). Centro de Ciencias e Tecnologias Agropecuarias (CCTA). Dept. de Producao Vegetal; Morais, Rafael Fiusa de; Urquiaga, Segundo; Boddey, Robert Michael; Alves, Bruno Jose Rodrigues [EMBRAPA Agrobiologia, Seropedica, RJ (Brazil)]. E-mail: bruno@cnpab.embrapa.br

    2008-09-15

    In commercial plantations of soybean in both the Southern and the Cerrado regions, contributions from biological nitrogen fixation (BNF) are generally proportionately high. When using the {sup 15}N natural abundance technique to quantify BNF inputs, it is essential to determine, with accuracy, the {sup 15}N abundance of the N derived from BNF (the 'B' value). This study aimed to determine the effect of four recommended strains of Bradyrhizobium spp. (two B. japonicum and two B. elkanii) on the 'B' value of soybean grown in pots in an open field using an equation based on the determination of {delta}{sup 15}N natural abundance in a non-labelled soil, and estimate of the contribution of BNF derived from the use of {sup 15}N-isotope dilution in soils enriched with {sup 15}N. To evaluate N{sub 2} fixation by soybean, three non-N{sub 2}-fixing reference crops were grown under the same conditions. Regardless of Bradyrhizobium strain, no differences were observed in dry matter, nodule weight and total N between labelled and non-labelled soil. The N{sub 2} fixation of the soybeans grown in the two soil conditions were similar. The mean 'B' values of the soybeans inoculated with the B. japonicum strains were -1.84 per mille and -0.50 per mille, while those inoculated with B. elkanii were -3.67 per mille and -1.0 per mille, for the shoot tissue and the whole plant, respectively. Finally, the 'B' value for the soybean crop varied considerably in function of the inoculated Bradyrhizobium strain, being most important when only the shoot tissue was utilised to estimate the proportion of N in the plant derived from N{sub 2} fixation. (author)

  7. Dynamics of the amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 10

    International Nuclear Information System (INIS)

    Gruhn, K.; Hennig, A.

    1989-01-01

    Over a period of 4 days 12 colostomized laying hens daily received 36 g coarse wheat meal containing 14.37 atom-% 15 N excess ( 15 N') together with a conventional ration. After the homogenisation of each oviduct N and 15 N' were determined. After the precipitation with TCA the 15 N' of the amino acids was analysed in both the precipitate and the supernatant. In addition, the free amino acids and the peptides were determined in the TCA soluble fraction. The atom-% 15 N' in the total N and in the non-basic amino acid N showed a parallel decrease; it diminshed from 1.75 atom-% 15 N' to 0.64. Of the three basic amino acids, lysine shows the lowest labelling at all four measuring points. The quotas of non-basic amino acid 14 N and 15 N' in the total 14 N and 15 N' of the oviduct are the same and amount to 53%. In contrast to this, the quota of the 14 N of the basic amino acids in the total 14 N of the oviduct only amounts to 21.6% and that of 15 N' only to 15.4%. The average atom-% 15 N' of the free amino acids 12 h after the last 15 N application is 1.54 and is considerably above that of the peptides with 1.15 atom-% 15 N'. 36 h after the last 15 N application the ascertained value of 1.25 is identical in both fractions. The labelling of the free amino acids decreases more quickly than that of the peptides the more time has passed after the last 15 N application. (author)

  8. Induction of adhesion-inhibitory antibodies against placental Plasmodium falciparum parasites by using single domains of VAR2CSA

    DEFF Research Database (Denmark)

    Nielsen, Morten A; Pinto, Vera V; Resende, Mafalda

    2009-01-01

    In areas of endemicity pregnancy-associated malaria is an important cause of maternal anemia, stillbirth, and delivery of low-birth-weight children. The syndrome is precipitated by the accumulation of Plasmodium falciparum-infected erythrocytes in the placenta, mediated through an interaction...... it is not possible to produce entire VAR2CSA recombinant proteins. Furthermore, the presence of polymorphisms has raised the question of whether it is feasible to define VAR2CSA antigens eliciting broadly protective antibodies. Thus, the challenge for vaccine development is to define smaller parts of the molecule...... was not limited to homologous parasite strains, it seems feasible to base a protective malaria vaccine on a single VAR2CSA DBL domain....

  9. Nuclear safety in France after Fukushima - Critical analysis of complementary safety assessments (CSA) carried out on French nuclear installations after Fukushima

    International Nuclear Information System (INIS)

    Makhijani, Arjun; Marignac, Yves

    2012-02-01

    This report proposes a critical analysis of the approach carried out on the basis of the CSA (complementary safety assessment), from their specifications to the IRSN conclusions. It is notably based on the analysis performed by EDF on three nuclear sites (Gravelines, Civaux and Flamanville) which encompass the different levels of the nuclear power plants in France and the EPR project under construction, and on the analysis performed by Areva for La Hague reprocessing plants. Due to the short delay, only some sites and some problems have been considered. The CSA methodology is described. The EDF approach is discussed as well as the IRSN analysis of reports made by EDF, and then the different case studies. Beyond the conclusions of these reports, the authors highlight several major possible accidents which must be taken into account. They also outline that this CSA approach is a good starting point for the strengthening of nuclear safety

  10. Improved 3D triple resonance experiments, HNN and HN(C)N, for HN and 15N sequential correlations in (13C, 15N) labeled proteins: Application to unfolded proteins

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Sanjay C.; Bhavesh, Neel S.; Hosur, Ramakrishna V. [Tata Institute of Fundamental Research, Department of Chemical Sciences (India)

    2001-06-15

    Two triple resonance experiments, HNN and HN(C)N, are presented which correlate H{sup N} and {sup 15}N resonances sequentially along the polypeptide chain of a doubly ({sup 13}C, {sup 15}N) labeled protein. These incorporate several improvements over the previously published sequences for a similar purpose and have several novel features. The spectral characteristics enable direct identification of certain triplets of residues, which provide many starting points for the sequential assignment procedure. The experiments are sensitive and their utility has been demonstrated with a 22 kDa protein under unfolding conditions where most of the standard triple resonance experiments such as HNCA, CBCANH etc. have limited success because of poor amide, C{sup {alpha}} and C{sup {beta}} chemical shift dispersions.

  11. The Influence of Sub-Unit Composition and Expression System on the Functional Antibody Response in the Development of a VAR2CSA Based Plasmodium falciparum Placental Malaria Vaccine

    DEFF Research Database (Denmark)

    Nielsen, Morten A; dos Santos Marques Resende, Mafalda; de Jongh, Willem A

    2015-01-01

    of VAR2CSA, a parasite-derived antigen. Protection against PM is mediated by antibodies that inhibit binding of IE in the placental intervillous space. VAR2CSA is a large antigen incompatible with large scale recombinant protein expression. Vaccines based on sub-units encompassing the functionally...... recombinant subunits of the VAR2CSA antigen is unpredictable, demonstrating the need for large-scale screening in order to identify antigens that induce a broadly strain-transcending antibody response....

  12. Dynamics of amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 1

    International Nuclear Information System (INIS)

    Hennig, A.; Gruhn, K.; Kirchner, E.

    1987-01-01

    In a 6-day preliminary period with a pelleted ration 12 colostomized laying hybrids received 15 N-labelled wheat protein over 4 days. The labelling of the wheat was 14.37 atom-% 15 N excess ( 15 N'). During the 4-day application of 15 N-labelled wheat protein each hen consumed 12.08 g N, 3.52 g lysine, 2.12 g histidine, 4.41 g arginine, of which were 540 mg 15 N', 18.1 mg lysine 15 N', 21.5 mg histidine 15 N' and 47.9 mg arginine 15 N'. Heavy nitrogen was determined in urine and its uric acid N in the daily urine samples of the individual animals. The average daily urine N excretion was 54% of the total nitrogen consumed with the ration. The labelling of the urine N reached a plateau on the fourth day of the experiment with 3.2 atom-% 15 N'. On an average of the total experiment the quota of heavy nitrogen of the uric acid in the total 15 N' of the urine was 83.4% and that of uric acid nitrogen in the total urine nitrogen 80.8%. (author)

  13. Ammonia detection of 1-D ZnO/polypyrrole nanocomposite: Effect of CSA doping and their structural, chemical, thermal and gas sensing behavior

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Shilpa [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); Karmakar, Narayan [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); Shah, Akshara [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); National Centre for Nanosciences& Nanotechnology, University of Mumbai, Santacruz (East), Mumbai-400098,India (India); Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon (India); Shimpi, Navinchandra G, E-mail: navin_shimpi@rediffmail.com [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098,India (India)

    2017-02-28

    Highlights: • Synthesis of 1-Dimensional ZnO-Polypyrrole nanocomposite using In-situ oxidative polymerization technique. • High response ammonia sensing. • Optimization of ZnO content in nanocomposites for maximum sensor response. • Effect of CSA doping on structural, thermal, optical and sensing behavior. • Optimization of CSA concentration for high sensitivity, fast response and recovery time. - Abstract: Nanocomposites of polypyrrole (PPy) with varying concentration of ZnO nanorods (ZnO NRs) were synthesized using in-situ oxidative polymerization technique. The prepared nanocomposites (PPy, PPy-ZnO and CSA doped PPy-ZnO) were studied for various oxidizing and reducing gases at room temperature and found to be more selective towards ammonia gas. Various concentrations of ZnO NRs in Ppy matrix were studied and 15% was found to be optimum in terms of sensor response (66% towards 120 ppm NH{sub 3}). Further, with 15% doping of camphor sulphonic acid (CSA) in PPy-ZnO nanocomposite for 15% ZnO NRs in Ppy matrix, sensor response increased from 66 to 79% towards 120 ppm of NH{sub 3}. Structural, Optical and thermal behavior of nanocomposites were studied using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) Spectroscopy, Thermo-gravimetric analysis (TGA) and Field Emission Scanning Electron Microscopy (FESEM). ZnO has been completely embedded inside the polymeric chains as observed from in SEM. Meanwhile, FT-IR spectra indicate better conjugation and interaction in nanocomposites. With CSA doping interaction grows stronger due to extended delocalization over π electrons leading to higher sensor response and with response time and recovery time of 24 s and 34 s respectively. CSA doped PPy-ZnO (15%) nanocomposites observed to be a potential candidate for ammonia detection at lower ppm level.

  14. Experimental flume study on Potamogeton natans and Ranunculus fluitans macrophytes: impact of hydrodynamics on 15N-ammonium uptake rates

    Science.gov (United States)

    Woule Ebongue, V.; Brion, N.; Hove, N.; Barrón, C.; Dehairs, F.; Bal, K.; Bouma, T.; Schoelynck, J.; de Deckere, E.; Meire, P.

    2010-12-01

    By means of incubations in a flume tank using 15N enriched ammonium label we investigate the concomitant effects of (i) different morphologies and specific surfaces, (ii) bulk water flow successively set at 0.3 and 0.1 m s-1 and (iii) three patch configurations on the rates of 15N-ammonium uptake rates for two macrophytes species: Potamogeton natans and Ranunculus fluitans. Because recent studies have shown that the rate of ammonium uptake by seagrass specimens depends on hydrodynamic factors such as shear stress and turbulence -which notably influence the rate at which ammonium is delivered to the surface of the leaves- these incubations were performed together with high resolution flow velocity measurements. Results of our experiments show higher 15N-ammonium uptake rates at the edges of patches in some of the incubations involving the two species. Currents and turbulence which are supposed to be the highest at the edges of the patches can explain these patterns. R. fluitans showing the highest specific surface of the two species is also the most efficient at obtaining 15N-ammonium from the water column in all experimental conditions. Results also show enhanced 15N-ammonium uptake rates with increased bulk water flow for both species. This result which is consistent with that of previous studies on seagrass communities is explained by turbulent energy and stresses factors that increase both advection of nutrients through the community and rates of diffusion at the surfaces of the specimens as flow velocity increases. Finally, flume configuration only affects uptake rates for R. fluitans at lower bulk flow velocity (0.1 m s-1). Higher 15N-ammonium uptake rates are observed for this species in the configuration when the flume is half filled compare to the configuration when the flume fully filled with both species. No significant difference is observed between the two configurations for P. natans. Our findings provide an improved insight in the concomitant effects

  15. Comparison of three 15N methods to correct for microbial contamination when assessing in situ protein degradability of fresh forages.

    Science.gov (United States)

    Kamoun, M; Ammar, H; Théwis, A; Beckers, Y; France, J; López, S

    2014-11-01

    The use of stable (15)N as a marker to determine microbial contamination in nylon bag incubation residues to estimate protein degradability was investigated. Three methods using (15)N were compared: (15)N-labeled forage (dilution method, LF), (15)N enrichment of rumen solids-associated bacteria (SAB), and (15)N enrichment of rumen liquid-associated bacteria (LAB). Herbage from forages differing in protein and fiber contents (early-cut Italian ryegrass, late-cut Italian ryegrass, and red clover) were freeze-dried and ground and then incubated in situ in the rumen of 3 steers for 3, 6, 12, 24, and 48 h using the nylon bag technique. The (15)N-labeled forages were obtained by fertilizing the plots where herbage was grown with (15)NH4 (15)NO3. Unlabeled forages (obtained from plots fertilized with NH4NO3) were incubated at the same time that ((15)NH4)2SO4 was continuously infused into the rumen of the steers, and then pellets of labeled SAB and LAB were isolated by differential centrifugation of samples of ruminal contents. The proportion of bacterial N in the incubation residues increased from 0.09 and 0.45 g bacterial N/g total N at 3 h of incubation to 0.37 and 0.85 g bacterial N/g total N at 48 h of incubation for early-cut and late-cut ryegrass, respectively. There were differences (P forage (late-cut ryegrass) was 0.51, whereas the corrected values were 0.85, 0.84, and 0.77 for the LF, SAB, and LAB methods, respectively. With early-cut ryegrass and red clover, the differences between uncorrected and corrected values ranged between 6% and 13%, with small differences among the labeling methods. Generally, methods using labeled forage or labeled SAB and LAB provided similar corrected degradability values. The accuracy in estimating the extent of degradation of protein in the rumen from in situ disappearance curves is improved when values are corrected for microbial contamination of the bag residue.

  16. Identification of active metabolism roots of sugarcane for the isotopic dilution technique with {sup 15}N; Identificacao de raizes metabolicamente ativas de cana-de-acucar pela tecnica da diluicao isotopica com {sup 15}N

    Energy Technology Data Exchange (ETDEWEB)

    Faroni, Carlos E.; Bologna, Isabela R.; Franco, Henrique C.J. [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz. Dept. de Solos e Nutricao de Plantas]. E-mail: cfaroni@cena.usp.br; irbologn@esalq.usp.br; hjfranco@cena.usp.br; Trivelin, Paulo C.O.; Vitti, Andre C. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis]. E-mail: pcotrive@cena.usp.br; acvitti@cena.usp.br

    2005-07-01

    The knowledge of the sugarcane roots growth dynamics, as well as of the root system architecture of its, better allows to understanding of the relations between the plant and its environment of production, making possible the handling from practical more efficient and sustainable agriculturists who result in increase of productivity and longevity of the culture. In the study of the development of the sugarcane root system has an aggravating one in what the root renewal between cycles is mentioned to it, or in the same cycle, becoming necessary the identification of alive or active metabolism roots in a total mass showed. The present study it had for objective to develop a methodology of sugarcane active metabolism roots identification in the ground, by means of the isotopic dilution technique with {sup 15}N. The sugarcane root system study it can be carried through with this isotopic marker saw leaf application, a time that {sup 15}N is translocated until the root system. The experiment was carried through in commercial area of sugarcane in the region of Piracicaba, State of Sao Paulo, in a Oxissoil, with one second sprouts again of cultivating RB85 5156. The urea was the vehicle of supply of the isotopic marker {sup 15}N, by means of solution applied to leaves of the plants. After harvest of the aerial part, carried through 96 hours after the application of the urea solution, had been opened trenches, transversally to the line of the culture, with dimensions of 1 m of length and 1,4 m of width. The ground samples had been harvested by means of monoliths (5,6 dm{sup -3}) in the depths of 0-20, 20-40, 40-60 and 60-80 cm, in the projection of the line of the culture and laterally in the distances of 14-42 cm and 42-70 cm of the culture line. In each depth of sampling, and the culture line projection, they had been separate samples of visually active roots. These samples had been considered standard for the determination for isotopic dilution technique of roots with

  17. Simple approach for the preparation of 15-15N2-enriched water for nitrogen fixation assessments: Evaluation, application and recommendations

    Directory of Open Access Journals (Sweden)

    Isabell eKlawonn

    2015-08-01

    Full Text Available Recent findings revealed that the commonly used 15N2 tracer assay for the determination of dinitrogen (N2 fixation can underestimate the activity of aquatic N2-fixing organisms. Therefore, a modification to the method using pre-prepared 15-15N2-enriched water was proposed. Here, we present a rigorous assessment and outline a simple procedure for the preparation of 15-15N2-enriched water. We recommend to fill sterile-filtered water into serum bottles and to add 15-15N2 gas to the water in amounts exceeding the standard N2 solubility, followed by vigorous agitation (vortex mixing ≥5 min. Optionally, water can be degassed at low-pressure (≥950 mbar for ten minutes prior to the 15-15N2 gas addition to indirectly facilitate the 15-15N2 dissolution. This preparation of 15-15N2-enriched water can be done within one hour using standard laboratory equipment. The final 15N-atom% excess was 5% after replacing 2–5% of the incubation volume with 15-15N2-enriched water. Notably, the addition of 15-15N2-enriched water can alter levels of trace elements in the incubation water due to the contact of 15-15N2-enriched water with glass, plastic and rubber ware during its preparation. In our tests, levels of trace elements (Fe, P, Mn, Mo, Cu, Zn increased by up to 0.1 nmol L-1 in the final incubation volume, which may bias rate measurements in regions where N2 fixation is limited by trace elements. For these regions, we tested an alternative way to enrich water with 15-15N2. The 15-15N2 was injected as a bubble directly to the incubation water, followed by gentle shaking. Immediately thereafter, the bubble was replaced with water to stop the 15-15N2 equilibration. This method achieved a 15N-atom excess of 6.6±1.7% when adding 2 mL 15-15N2 per liter of incubation water. The herein presented methodological tests offer guidelines for the 15N2 tracer assay and thus, are crucial to circumvent methodological draw-backs for future N2 fixation assessments.

  18. O potencial da rotulação metabólica de 15N para a pesquisa de esquizofrenia

    Directory of Open Access Journals (Sweden)

    Michaela D. Filiou

    2013-01-01

    Full Text Available Pesquisas em psiquiatria ainda necessitam de estudos não dirigidos por hipóteses para revelar fundamentos neurobiológicos e biomarcadores moleculares para distúrbios psiquiátricos. Metodologias proteômicas disponibilizam uma série de ferramentas para esses fins. Apresentamos o princípio de rotulação metabólica utilizando 15N para proteômica quantitativa e suas aplicações em modelos animais de fenótipos psiquiátricos com um foco particular em esquizofrenia. Exploramos o potencial de rotulação metabólica por 15N em diferentes tipos de experimentos, bem como suas considerações metodológicas.

  19. Target-specific NMR detection of protein-ligand interactions with antibody-relayed 15N-group selective STD.

    Science.gov (United States)

    Hetényi, Anasztázia; Hegedűs, Zsófia; Fajka-Boja, Roberta; Monostori, Éva; Kövér, Katalin E; Martinek, Tamás A

    2016-12-01

    Fragment-based drug design has been successfully applied to challenging targets where the detection of the weak protein-ligand interactions is a key element. 1 H saturation transfer difference (STD) NMR spectroscopy is a powerful technique for this work but it requires pure homogeneous proteins as targets. Monoclonal antibody (mAb)-relayed 15 N-GS STD spectroscopy has been developed to resolve the problem of protein mixtures and impure proteins. A 15 N-labelled target-specific mAb is selectively irradiated and the saturation is relayed through the target to the ligand. Tests on the anti-Gal-1 mAb/Gal-1/lactose system showed that the approach is experimentally feasible in a reasonable time frame. This method allows detection and identification of binding molecules directly from a protein mixture in a multicomponent system.

  20. Investigations on the transformation of N-fertilizer and the mineralization of organic N using 15N Pt. 1

    International Nuclear Information System (INIS)

    Latkovics, Gy.-ne

    1979-01-01

    A composting experiment was set up on chernozem-type brown forest soil to investigate the transformation of nitrogen fertilizer and the mineralization of organic N. For the average soil sample from the ploughed layer the pH value was 7.1, the mineral N content 2.85 mg, the fixed ammonium content 15.98 mg and the total N 140.8 mg100/g soil. The humus content was 1.91%. In the experiment 15 N labelled ammonium nitrate was used, and, as 15 N labelled organic matter, ground, air-dried rye-grass and bean stalks and with approximately the same N content as the 0.4% of the soil quantity measured. The values obtained by chemical methods and isotope indication show that the N-loss during composting was negligible and that the methods tested are suitable for the investigation of the transformation processes of nitrogen. (author)

  1. Alanine flux in obese and healthy humans as evaluated by 15N- and 2H3-labeled alanines

    International Nuclear Information System (INIS)

    Hoffer, L.J.; Yang, R.D.; Matthews, D.E.; Bistrian, B.R.; Bier, D.M.; Young, V.R.

    1988-01-01

    Estimates of plasma alanine flux as measured in humans using L-[ 15 N]-alanine or L-[3,3,3- 2 H 3 ]alanine were compared by simultaneous intravenous infusion of both tracers. Plasma isotope enrichments were measured by chemical ionization gas chromatography-mass spectrometry. In 16 obese women before and during a hypocaloric diet and in 4 normal men in the postabsorptive and fed states, the fluxes were highly correlated (r2 = 0.93) although plasma alanine flux with the 2 H tracer was two to three times greater than that obtained with [ 15 N]alanine. The fluxes decreased with the hypocaloric diet in obese subjects and increased during the fed state in healthy adults. Thus, although the estimates of alanine flux differed according to the tracer used, both appear to give equivalent information about changes in alanine kinetics induced by the nutritional conditions examined

  2. Mutable Lewis and Bronsted Acidity of Aluminated SBA-15 as Revealed by NMR of Adsorbed Pyridine-(15)N

    Czech Academy of Sciences Publication Activity Database

    Gurinov, A. A.; Rozhkova, Yu. A.; Zukal, Arnošt; Čejka, Jiří; Shenderovich, I, G.

    2011-01-01

    Roč. 27, č. 19 (2011), s. 12115-12123 ISSN 0743-7463 R&D Projects: GA AV ČR KAN100400701; GA ČR GA203/08/0604 Institutional research plan: CEZ:AV0Z40400503 Keywords : 15N NMR * post-synthesis alumination * phase Beckmann rearrangement Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.186, year: 2011

  3. FAO/IAEA - interregional training course on the use of 15N in soil science and plant nutrition

    International Nuclear Information System (INIS)

    Faust, H.

    1981-03-01

    This training manual provides an introduction for the basic methodology and principles of application of the stable isotope 15 N. After preliminary remarks on stable isotope terminology fundamentals, experimental problems and methods of quantitative nitrogen determination in soil and plant studies are reported in the main part of the manual. An appendix with a compilation of different parameters such as natural abundance of stable isotopes, selected atomic weights and multiples of them conversion factors of chemical compounds, and much more concludes the manual

  4. 15N NMR spectroscopic investigation of nitrous and nitric acids in sulfuric acid solutions of varying acidities

    International Nuclear Information System (INIS)

    Prakash, G.K.S.; Heiliger, L.; Olah, G.A.

    1990-01-01

    Both nitrous and nitric acids were studied in sulfuric acid solutions of varying acid strengths by 15 N NMR spectroscopy. The study gives new insights into the nature of intermediates present at different acid strengths. Furthermore, we have also discovered a novel redox reaction between NO 2 + and NO + ions involving the intermediacy of their respective acids. A mechanism is proposed to explain the observed results. 13 refs., 2 figs., 1 tab

  5. Filtration via Conventional Glass Fiber Filters in 15N2 Tracer Assays Fails to Capture All Nitrogen-Fixing Prokaryotes

    OpenAIRE

    Deniz Bombar; Ryan W. Paerl; Ruth Anderson; Lasse Riemann

    2018-01-01

    Biological dinitrogen fixation (BNF) represents a major input of reduced nitrogen (N) to the oceans. Accurate direct measurements of BNF rates are crucial for reliably determining the biogeochemical significance of diazotrophy at local and global scales. Traditionally, borosilicate glass fiber filters (GF/F, Whatman) with a nominal pore size of 0.7 μm are used to collect suspended particles by filtration after incubations with added 15N2 tracer. We carried out BNF experiments in the Baltic Se...

  6. Influence of canopy drip on the indicative N, S and δ15N content in moss Hypnum cupressiforme

    International Nuclear Information System (INIS)

    Skudnik, Mitja; Jeran, Zvonka; Batič, Franc; Simončič, Primož; Lojen, Sonja; Kastelec, Damijana

    2014-01-01

    Samples of Hypnum cupressiforme were collected at two types of site in forest areas: within the forest stand and within forest openings, and analyzed for N and S concentrations and δ 15 N. Mosses sampled within forest openings reflect the atmospheric N deposition; however, no influence of throughfall N deposition on the N in the moss that was sampled within the forest stand was found, nor was any influence of S deposition on the S in the moss found. For the N and S concentrations in the mosses sampled within forest openings, the within-site variability was comparable to the between-site variability, and for the δ 15 N, the within-site variability was lower than the between-site. The results showed that a short distance ( 15 N content in moss on atmospheric deposition. • Moss sampled within forest openings reflect the atmospheric N but not S deposition. • Higher N and S content was found in mosses sampled in areas within the forest stand. • Metadata describing the boundary condition of moss sampling location is important. - H. cupressiforme reflects the atmospheric deposition of N but not S; a distance less than 1 m between the sampling site and the nearest tree crown increases the N and S concentrations in the moss

  7. Auto-inducing media for uniform isotope labeling of proteins with 15N, 13C and 2H

    International Nuclear Information System (INIS)

    Guthertz, Nicolas; Klopp, Julia; Winterhalter, Aurélie; Fernández, César; Gossert, Alvar D.

    2015-01-01

    Auto-inducing media for protein expression offer many advantages like robust reproducibility, high yields of soluble protein and much reduced workload. Here, an auto-inducing medium for uniform isotope labelling of proteins with 15 N, 13 C and/or 2 H in E. coli is presented. So far, auto-inducing media have not found widespread application in the NMR field, because of the prohibitively high cost of labeled lactose, which is an essential ingredient of such media. Here, we propose using lactose that is only selectively labeled on the glucose moiety. It can be synthesized from inexpensive and readily available substrates: labeled glucose and unlabeled activated galactose. With this approach, uniformly isotope labeled proteins were expressed in unattended auto-inducing cultures with incorporation of 13 C, 15 N of 96.6 % and 2 H, 15 N of 98.8 %. With the present protocol, the NMR community could profit from the many advantages that auto-inducing media offer

  8. Bioconcentration of (15)N-tamoxifen at environmental concentration in liver, gonad and muscle of Danio rerio.

    Science.gov (United States)

    Orias, Frédéric; Simon, Laurent; Mialdea, Gladys; Clair, Angéline; Brosselin, Vanessa; Perrodin, Yves

    2015-10-01

    Pharmaceutical compounds (PCs) are ubiquitous in aquatic ecosystems. In addition to the direct ecotoxicological risk presented by certain PCs, others can accumulate inside organisms and along trophic webs, subsequently contaminating whole ecosystems. We studied the bioconcentration of a bioaccumulative PC already found several times in the environment: tamoxifen. To this end, we exposed Danio rerio for 21d to (15)N-tamoxifen concentrations ranging from 0.1 to 10µg/L and used an analytic method based on stable isotopes to evaluate the tamoxifen content in these organisms. The evolution of the (15)N/(14)N ratio was thus measured in liver, muscle and gonads of exposed fish compared to control fish. We succeeded in quantifying (15)N-tamoxifen bioconcentrations at all the exposure concentrations tested. The highest bioconcentration factors of tamoxifen measured were 14,920 in muscle, 73,800 in liver and 85,600 in gonads of fish after 21d exposure at a nominal concentration of 10µg/L. However, these bioconcentration factors have to be considered as maximal values (BCFMAX). Indeed, despite its proven stability, tamoxifen can be potentially partially degraded during experiments. We now need to refine these results by using a direct analytic method (i.e. LC-MS/MS). Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Influence of organic N Sources on N transformation and uptake by lupine plants using 15N technique

    International Nuclear Information System (INIS)

    Abdel-Salam, A.A.; Gadalla, A.M.; Abdel- Aziz, H.A.; Galal, Y.G.M.; EL-degwy, S.M.

    2008-01-01

    A pot experiment was carried out under greenhouse conditions to evaluate the comparative efficiency and transformation of nitrogen applied either as mineral or organic forms. The obtained data showed that shoot dry weight was enhanced by compost and its mixture with leucaena. When organic sources were combined with 15 N, the leucaena.compost mixture (LC p ) gave the highest yield, and the other two were not significantly different from each other. Reinforcing the organic N with mineral N caused an average greater N.uptake over the non reinforced treatment. Similar trend was noticed with root system. Nitrogen uptake by roots was increased according to the order of LC > L > C. N derived from fertilizer (% Ndff) by lupine shoots was significantly affected by fertilizer addition either alone or reinforced with organic plant residues. Both, the portions (%) or absolute values (mg pot -1 ) of Ndff were increased by adding the organic residues. The highest value of Ndfs was recorded with application of leucaena followed by compost, then Leucaena + compost. Portion Ndfa reflected an effective response of lupines plants to Rhizobium inoculation. Addition of LC mixture combined with 15 N-fertilizer had enhanced the N 2 fixation and increased Ndfa value by about 66.7 % over those recorded with 15 N0 treatment. Organic amendment of leucaena could be an efficient source for N to infertile sandy soils

  10. {sup 15}N relaxation study of the cold shock protein CspB at various solvent viscosities

    Energy Technology Data Exchange (ETDEWEB)

    Zeeb, Markus; Jacob, Maik H. [Universitaet Bayreuth, Laboratorium fuer Biochemie (Germany); Schindler, Thomas [Hoffmann LaRoche AG (Switzerland); Balbach, Jochen [Universitaet Bayreuth, Laboratorium fuer Biochemie (Germany)], E-mail: jochen.balbach@uni-bayreuth.de

    2003-11-15

    For a detailed NMR study of the dynamics of the cold shock protein CspB from Bacillus subtilis, we determined {sup 15}N transverse and longitudinal relaxation rates and heteronuclear nuclear Overhauser effects at different solvent viscosities. Up to a relative viscosity of 2, which is equivalent to 27% ethylene glycol (EG), the overall correlation time follows the linear Stokes-Einstein equation. At a relative viscosity of 6 (70% EG) the correlation time deviates from linearity by 30%, indicating that CspB tumbles at a higher rate as expected from the solvent viscosity probably due to a preferential binding of water molecules at the protein surface. The corresponding hydrodynamic radii, determined by NMR diffusion experiments, show no variation with viscosity. The amplitudes of intramolecular motions on a sub-nanosecond time scale revealed by an extended Lipari-Szabo analysis were mainly independent of the solvent viscosity. The lower limit of the NMR 'observation window' for the internal correlation time shifts above 0.5 ns at 70% EG, which is directly reflected in the experimentally derived internal correlation times. Chemical exchange contributions to the transverse relaxation rates derived from the Lipari-Szabo approach coincide with the experimentally determined values from the transverse {sup 1}H-{sup 15}N dipolar/{sup 15}N chemical shift anisotropy relaxation interference. These contributions originate from fast protein folding reactions on a millisecond timescale, which get retarded at increased solvent viscosities.

  11. (13)C, (15)N CPMAS NMR and GIAO DFT calculations of stereoisomeric oxindole alkaloids from Cat's Claw (Uncaria tomentosa).

    Science.gov (United States)

    Paradowska, Katarzyna; Wolniak, Michał; Pisklak, Maciej; Gliński, Jan A; Davey, Matthew H; Wawer, Iwona

    2008-11-01

    Oxindole alkaloids, isolated from the bark of Uncaria tomentosa [Willd. ex Schult.] Rubiaceae, are considered to be responsible for the biological activity of this herb. Five pentacyclic and two tetracyclic alkaloids were studied by solid-state NMR and theoretical GIAO DFT methods. The (13)C and (15)N CPMAS NMR spectra were recorded for mitraphylline, isomitraphylline, pteropodine (uncarine C), isopteropodine (uncarine E), speciophylline (uncarine D), rhynchophylline and isorhynchophylline. Theoretical GIAO DFT calculations of shielding constants provide arguments for identification of asymmetric centers and proper assignment of NMR spectra. These alkaloids are 7R/7S and 20R/20S stereoisomeric pairs. Based on the (13)C CP MAS chemical shifts the 7S alkaloids (delta C3 70-71ppm) can be easily and conveniently distinguished from 7R (deltaC3 74.5-74.9ppm), also 20R (deltaC20 41.3-41.7ppm) from the 20S (deltaC20 36.3-38.3ppm). The epiallo-type isomer (3R, 20S) of speciophylline is characterized by a larger (15)N MAS chemical shift of N4 (64.6ppm) than the allo-type (3S, 20S) of isopteropodine (deltaN4 53.3ppm). (15)N MAS chemical shifts of N1-H in pentacyclic alkaloids are within 131.9-140.4ppm.

  12. Validating the Incorporation of 13C and 15N in a Shorebird That Consumes an Isotopically Distinct Chemosymbiotic Bivalve.

    Science.gov (United States)

    van Gils, Jan A; Ahmedou Salem, Mohamed Vall

    2015-01-01

    The wealth of field studies using stable isotopes to make inferences about animal diets require controlled validation experiments to make proper interpretations. Despite several pleas in the literature for such experiments, validation studies are still lagging behind, notably in consumers dwelling in chemosynthesis-based ecosystems. In this paper we present such a validation experiment for the incorporation of 13C and 15N in the blood plasma of a medium-sized shorebird, the red knot (Calidris canutus canutus), consuming a chemosymbiotic lucinid bivalve (Loripes lucinalis). Because this bivalve forms a symbiosis with chemoautotrophic sulphide-oxidizing bacteria living inside its gill, the bivalve is isotopically distinct from 'normal' bivalves whose food has a photosynthetic basis. Here we experimentally tested the hypothesis that isotope discrimination and incorporation dynamics are different when consuming such chemosynthesis-based prey. The experiment showed that neither the isotopic discrimination factor, nor isotopic turnover time, differed between birds consuming the chemosymbiotic lucinid and a control group consuming a photosynthesis-based bivalve. This was true for 13C as well as for 15N. However, in both groups the 15N discrimination factor was much higher than expected, which probably had to do with the birds losing body mass over the course of the experiment.

  13. Validating the Incorporation of 13C and 15N in a Shorebird That Consumes an Isotopically Distinct Chemosymbiotic Bivalve.

    Directory of Open Access Journals (Sweden)

    Jan A van Gils

    Full Text Available The wealth of field studies using stable isotopes to make inferences about animal diets require controlled validation experiments to make proper interpretations. Despite several pleas in the literature for such experiments, validation studies are still lagging behind, notably in consumers dwelling in chemosynthesis-based ecosystems. In this paper we present such a validation experiment for the incorporation of 13C and 15N in the blood plasma of a medium-sized shorebird, the red knot (Calidris canutus canutus, consuming a chemosymbiotic lucinid bivalve (Loripes lucinalis. Because this bivalve forms a symbiosis with chemoautotrophic sulphide-oxidizing bacteria living inside its gill, the bivalve is isotopically distinct from 'normal' bivalves whose food has a photosynthetic basis. Here we experimentally tested the hypothesis that isotope discrimination and incorporation dynamics are different when consuming such chemosynthesis-based prey. The experiment showed that neither the isotopic discrimination factor, nor isotopic turnover time, differed between birds consuming the chemosymbiotic lucinid and a control group consuming a photosynthesis-based bivalve. This was true for 13C as well as for 15N. However, in both groups the 15N discrimination factor was much higher than expected, which probably had to do with the birds losing body mass over the course of the experiment.

  14. Symbiotic nitrogen fixation in a tropical rainforest: 15N natural abundance measurements supported by experimental isotopic enrichment.

    Science.gov (United States)

    Pons, Thijs L; Perreijn, Kristel; van Kessel, Chris; Werger, Marinus J A

    2007-01-01

    * Leguminous trees are very common in the tropical rainforests of Guyana. Here, species-specific differences in N(2) fixation capability among nodulating legumes growing on different soils and a possible limitation of N(2) fixation by a relatively high nitrogen (N) and low phosphorus (P) availability in the forest were investigated. * Leaves of 17 nodulating species and 17 non-nodulating reference trees were sampled and their delta(15)N values measured. Estimates of N(2) fixation rates were calculated using the (15)N natural abundance method. Pot experiments were conducted on the effect of N and P availability on N(2) fixation using the (15)N-enriched isotope dilution method. * Nine species showed estimates of > 33% leaf N derived from N(2) fixation, while the others had low or undetectable N(2) fixation rates. High N and low P availability reduced N(2) fixation substantially. * The results suggest that a high N and low P availability in the forest limit N(2) fixation. At the forest ecosystem level, N(2) fixation was estimated at c. 6% of total N uptake by the tree community. We conclude that symbiotic N(2) fixation plays an important role in maintaining high amounts of soil available N in undisturbed forest.

  15. 15N NMR investigation of the reduction and binding of TNT in an aerobic bench scale reactor simulating windrow composting

    Science.gov (United States)

    Thorn, K.A.; Pennington, J.C.; Hayes, C.A.

    2002-01-01

    T15NT was added to a soil of low organic carbon content and composted for 20 days in an aerobic bench scale reactor. The finished whole compost and fulvic acid, humic acid, humin, and lignocellulose fractions extracted from the compost were analyzed by solid-state CP/MAS and DP/MAS 15N NMR. 15N NMR spectra provided direct spectroscopic evidence for reduction of TNT followed by covalent binding of the reduced metabolites to organic matter of the composted soil, with the majority of metabolite found in the lignocellulose fraction, by mass also the major fraction of the compost. In general, the types of bonds formed between soil organic matter and reduced TNT amines in controlled laboratory reactions were observed in the spectra of the whole compost and fractions, confirming that during composting TNT is reduced to amines that form covalent bonds with organic matter through aminohydroquinone, aminoquinone, heterocyclic, and imine linkages, among others. Concentrations of imine nitrogens in the compost spectra suggestthat covalent binding bythe diamines 2,4DANT and 2,6DANT is a significant process in the transformation of TNT into bound residues. Liquid-phase 15N NMR spectra of the fulvic acid and humin fractions provided possible evidence for involvement of phenoloxidase enzymes in covalent bond formation.

  16. The excretion of isotope in urea and ammonia for estimating protein turnover in man with [15N]glycine

    International Nuclear Information System (INIS)

    Fern, E.B.; Garlick, P.J.; McNurlan, M.A.; Waterlow, J.C.

    1981-01-01

    Four normal adults were given [ 15 N]-glycine in a single dose either orally or intravenously. Rates of whole-body protein turnover were estimated from the excretion of 15 N in ammonia and in urea during the following 9 h. The rate derived from urea took account of the [ 15 N]urea retained in body water. In postabsorptive subjects the rates of protein synthesis given by ammonia were equal to those from urea, when the isotope was given orally, but lower when an intravenous dose was given. In subjects receiving equal portions of food every 2 h rates of synthesis calculated from ammonia were much lower than those from urea whether an oral or intravenous isotope was given. Comparison of rates obtained during the postabsorptive and absorptive periods indicated regulation by food intake primarily of synthesis when measurements were made on urea, but regulation primarily of breakdown when measurements were made on ammonia. These inconsistencies suggest that changes in protein metabolism might be assessed better by correlating results given by different end-products, and it is suggested that the mean value given by urea and ammonia will be useful for this purpose. (author)

  17. Differentiation of Pigment in Eggs Using Carbon ((13)C/(12)C) and Nitrogen ((15)N/(14)N) Stable Isotopes.

    Science.gov (United States)

    Sun, Feng M; Shi, Guang Y; Wang, Hui W

    2016-07-01

    Consumers prefer natural and healthy food, but artificial pigments are often abused in egg products. The study aimed at differentiating the origin of pigments in eggs by applying the technique of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) stable isotope analysis. Five hundred sixty laying hens were randomly distributed into 14 treatments, which were divided into four groups: maize, carophyll red pigment, carophyll yellow pigment, and a mixture of carophyll red and yellow pigments. Eggs were collected and pretreated to determe the values of the Roche Yolk Color Fan (RCF), δ(13)C, and δ(15)N. With increasing maize content, the RCF and δ(13)C values of yolks increased. Moreover, the RCF values in the three pigment groups were significantly influenced by the artificial colors, but δ(13)C values were not significantly different, regardless of the existence of pigment. The δ(15)N values in all treatments did not vary as regularly as the carbon stable isotope. A strong positive correlation was found between RCF and δ(13)C in the maize group, but no such correlation was be observed in the pigment groups. It is concluded that carbon stable isotope ratio analysis (δ(13)C) of the yolk can be used to differentiate the origin of the pigment added to eggs.

  18. (13)C and (15)N NMR characterization of amine reactivity and solvent effects in CO2 capture.

    Science.gov (United States)

    Perinu, Cristina; Arstad, Bjørnar; Bouzga, Aud M; Jens, Klaus-J

    2014-08-28

    Factors influencing the reactivity of selected amine absorbents for carbon dioxide (CO2) capture, in terms of the tendency to form amine carbamate, have been studied. Four linear primary alkanolamines at varying chain lengths (MEA, 3A1P, 4A1B , and 5A1P ), two primary amines with different substituents in the β-position to the nitrogen (1A2P and ISOB), a secondary alkanolamine (DEA), and a sterically hindered primary amine (AMP) were investigated. The relationship between the (15)N NMR data of aqueous amines and their ability to form carbamate, as determined at equilibrium by quantitative (13)C NMR experiments, was analyzed, taking into account structural-chemical properties. For all the amines, the (15)N chemical shifts fairly reflected the observed reactivity for carbamate formation. In addition to being a useful tool for the investigation of amine reactivity, (15)N NMR data clearly provided evidence of the importance of solvent effects for the understanding of chemical dynamics in CO2 capture by aqueous amine absorbents.

  19. Tracing the diet of the monitor lizard Varanus mabitang by stable isotope analyses (δ15N, δ13C)

    Science.gov (United States)

    Struck, Ulrich; Altenbach, Alexander; Gaulke, Maren; Glaw, Frank

    2002-09-01

    In this study, we used analyses of stable isotopes of nitrogen (δ15N) and carbon (δ13C) to determine the trophic ecology of the monitor lizard Varanus mabitang. Stable isotopes from claws, gut contents, and soft tissues were measured from the type specimen. Samples from Varanus olivaceus, Varanus prasinus, Varanus salvator, the herbivorous agamid lizard Hydrosaurus pustulatus, and some plant matter were included for comparison. Our data show a rapid decrease in δ13C (about10‰) from food plants towards gut contents and soft tissues of herbivorous species. For the varanids, we found a significant linear correlation of decreasing δ13C and increasing δ15N from herbivorous towards carnivorous species. In terms of trophic isotope ecology, the type specimen of V. mabitang is a strict herbivore. Thus it differs significantly in its isotopic composition from the morphologically next closest related species V. olivaceus. The most highly carnivorous species is V. salvator, while δ15N values for V. prasinus and V. olivaceus are intermediate. Claws provide very valuable samples for such measurements, because they can be sampled from living animals without harm. Additionally, their range of variability is relatively small in comparison with measurements from soft tissues.

  20. Dynamics of the amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 11

    International Nuclear Information System (INIS)

    Gruhn, K.; Zander, R.

    1989-01-01

    Over a period of 4 days 12 colostomized laying hens daily received 36 g 15 N-labelled wheat with 15 N excess ( 15 N') of 14.37 atom-% together with a conventional feed mixture for laying hens. The labelling of the lysine N in the wheat was 13.58 atom-%, that of histidine N 14.38 and that of arginine 15 N' 13.63 atom-% 15 N'. Three hens each were butchered 12, 36, 60 and 108 h after the last 15 N' feeding. The first three hens did not receive any feed before being butchered. The following three hens each received the unlabelled feed ration for another 1, 2 or 4 days, resp., after the main period until they were butchered. The total of skeleton muscles, heart and stomach muscle (without inner skin) of each hen were combined into one sample, cut thinly, drenched with fluid nitrogen and pulverized. N, 15 N' and the basic and non-basic amino acids as well as their 15 N' were determined in the individual samples. In contrast to the organs, the proteins in the muscle tissue have a long half-life so that a slight decrease of atom-% 15 N' in the muscles could only be detected after 108 h. The 14 N and 15 N' quota of the non-basic amino acids in the total nitrogen of the muscles is 50 %. The 14 N quota of the basic amino acids is 30% and the 15 N' quota only 22.5% in the total muscle N. The heavy nitrogen of the free lysine in the TCA soluble N fraction is hardly detectable 36 h and 60 h after the last 15 N' supply and not at all after 108 h. In contrast to this, the other two free basic amino acids remain significantly higher labelled in dependence on the last butchering time. (author)

  1. Dynamics of the amino acid and protein metabolism of laying hens after the application of 15N-labelled wheat protein. 6

    International Nuclear Information System (INIS)

    Gruhn, K.; Kirchner, E.

    1988-01-01

    12 colostomized laying hens received, together with a conventional feed ration, 15 N-labelled wheat with a 15 N excess ( 15 N') of 14.37 atom-% over 4 days. 3 animals each were butchered after 12 h, 36 h, 60 h and 108 h after the last 15 N' application and, apart from various organs, the contents and the tissue of the gastrointestinal tract of each hen was divided into 3 fractions. TCA precipitation was carried out with the contents and the tissue of the 3 fractions. Nitrogen and its atom-% 15 N' were determined in the supernatant and the precipitate. The 15 N' amount in the contents of the crop and the stomachs, the small and large intestines is still considerable 12 h after the last 15 N wheat feeding and still clearly detectable 108 h after it. The TCA precipitable amounts of 14 N and 15 N' of the contents of crop and stomach and that of the small intestine agree well; they are 75% and 50% resp. of the total N. The amount of atom-% 15 N' of the contents of the small and large intestines remains the same up to 36 h after the last 15 N' application and is higher at the following measuring points in the contents of the large intestine. A close correlation could be ascertained between the atom-% 15 N' in the contents and tissue of the small and large intestines. The TCA soluble N quotas of both 14 N and 15 N' in the pancreas are above 50%. (author)

  2. The natural abundance of 15N in litter and soil profiles under six temperate tree species: N cycling depends on tree species traits and site fertility

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Nilsson, Lars Ola; Schmidt, Inger Kappel

    2013-01-01

    for these N variables and for the litter δ15N and enrichment factor. Litter from ash and sycamore maple with high N status and low fungal mycelia activity was enriched in 15N (+0.9 delta units) relative to other tree species (European beech, pedunculate oak, lime and Norway spruce) even though the latter...... species leached more nitrate.The δ15N pattern reflected tree species related traits affecting the N cycling as well as site fertility and former land use, and possibly differences in N leaching. The tree species δ15N patterns reflected fractionation caused by uptake of N through mycorrhiza rather than due...

  3. Plant δ15 N reflects the high landscape-scale heterogeneity of soil fertility and vegetation productivity in a Mediterranean semiarid ecosystem.

    Science.gov (United States)

    Ruiz-Navarro, Antonio; Barberá, Gonzalo G; Albaladejo, Juan; Querejeta, José I

    2016-12-01

    We investigated the magnitude and drivers of spatial variability in soil and plant δ 15 N across the landscape in a topographically complex semiarid ecosystem. We hypothesized that large spatial heterogeneity in water availability, soil fertility and vegetation cover would be positively linked to high local-scale variability in δ 15 N. We measured foliar δ 15 N in three dominant plant species representing contrasting plant functional types (tree, shrub, grass) and mycorrhizal association types (ectomycorrhizal or arbuscular mycorrhizal). This allowed us to investigate whether δ 15 N responds to landscape-scale environmental heterogeneity in a consistent way across species. Leaf δ 15 N varied greatly within species across the landscape and was strongly spatially correlated among co-occurring individuals of the three species. Plant δ 15 N correlated tightly with soil δ 15 N and key measures of soil fertility, water availability and vegetation productivity, including soil nitrogen (N), organic carbon (C), plant-available phosphorus (P), water-holding capacity, topographic moisture indices and normalized difference vegetation index. Multiple regression models accounted for 62-83% of within-species variation in δ 15 N across the landscape. The tight spatial coupling and interdependence of the water, N and C cycles in drylands may allow the use of leaf δ 15 N as an integrative measure of variations in moisture availability, biogeochemical activity, soil fertility and vegetation productivity (or 'site quality') across the landscape. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  4. Using 15N-glycine trace technique to observe the influence of growth hormone on the rate of whole body protein metabolism in dwarfism

    International Nuclear Information System (INIS)

    Wu Jingchuan; Wu Zhen; Wu Jizong

    1993-01-01

    The changes of whole body protein metabolism was studied using one oral dose 15 N-glycine. Urine 15 N excretion 24 hours before and after injected growth hormone (GH) was measured in 9 cases of dwarfism. The results showed that in children with growth hormone deficiency (CHD) with low nitrogen balance, rate of protein syntheses and 15 N retention capability were significantly increased after treatment with GH. Children with constitutional growth delay (CGD) with normal parameters of nitrogen balance showed no difference before and after treatment of GH. It was concluded that 15 N trace might be a supplementary tool for the diagnosis and differential diagnosis of dwarfism

  5. Determination of symbiotic nitrogen fixation by labelling the soil atmosphere with sup(15)N sub(2) at low isotope enrichment

    International Nuclear Information System (INIS)

    Trivelin, P.C.O.

    1982-01-01

    A direct method to determine the total symbiotic nitrogen fixation during the leguminous plants cycles has been, developed, by labelling the soil atmosphere with sup(15)N sub(2) at low isotope enrichment, of about 1 atom % excess. The soil explored by the root system of leguminous plants was confined by means of a chamber in the field and by sealed pots in greenhouse experiments in order to maintain the soil air labelled with sup(15)N sub(2). The average sup(15)N concentration in the soil atmosphere, necessary to calculate dinitrogen fixation, was obtained by integration of the exponential functions of isotope dilution. Those functions were obtained by periodic sampling and analysis of the N sub(2) in the soil atmosphere. The field experiment with labelled atmosphere was carried out from the 22 sup(nd) to the 31 sup(st) day of the bean crop cycle and 5.5 mg N/plant (24% of total plant N) was derived from fixation. In pot experiments, under greenhouse conditions, integrated determination of fixation was made in Phaseolus beans (from the 19 sup(th) to the 67 sup(th) day from planting) and in soybeans (from the 24 sup(th) to the 70 sup(th) day from planting). The soil atmosphere was labelled with sup(15)N sub(2) in both cases. Average fixation obtained for Phaseolus beans was 80 mg N/plant (65% of total plant N) and for soybeans 265 mg N/plant (71% of total plant N). Evaluation of the basic concept of the isotope dilution method to determine nitrogen fixation in pots experiments, as proposed by Fried and Middelboe (1977) has also been made in the present paper. Simultaneous determinations of fixation in soybeans, using the isotope dilution method of Fried and Middelboe, natural variation of the sup(15)N/ sup(14)N ratios, and total-N differences, indicated the same results for pot experiments, harvested at the end of the plant cycle. (author)

  6. Mangrove isotopic (δ15N and δ13C) fractionation across a nitrogen vs. phosphorus limitation gradient

    Science.gov (United States)

    Mckee, Karen L.; Feller, Ilka C.; Popp, Marianne; Wanek, Wolfgang

    2002-01-01

    Mangrove islands in Belize are characterized by a unique switching from nitrogen (N) to phosphorus (P) limitation to tree growth from shoreline to interior. Fertilization has previously shown that Rhizophora mangle (red mangrove) fringe trees (5–6 m tall) growing along the shoreline are N limited; dwarf trees (!1.5 m tall) in the forestinterior are P limited; and transition trees (2–4 m tall) are co-limited by both N and P.  Growth patterns paralleled a landward decrease in soil flushing by tides and an increase in bioavailable N, but P availability remained consistently low across the gradient. Stable isotopic composition was measured in R. mangle leaves to aid in explaining this nutrient switching pattern and growth variation. Along control transects, leaf !15N decreased from "0.10‰ (fringe) to #5.38‰ (dwarf). The !15N of N-fertilized trees also varied spatially, but the values were consistently more negative (by $3‰) compared to control trees. Spatial variation in !15N values disappeared when the trees were fertilized with P, and values averaged "0.12‰, similar to that in control fringe trees. Neither variation in source inputs nor microbial fractionation could fully account for the observed patterns in !15N. The results instead suggest that the lower !15N values in transition and dwarf control trees were due to plant fractionation as a consequence of slower growth and lower N demand. P fertilization increased N demand and decreased fractionation. Although leaf !13C was unaffected by fertilization, values increased from fringe (#28.6‰) to transition (#27.9‰) to dwarf (#26.4‰) zones, indicating spatial variation in environmental stresses affecting stomatal conductance or carboxylation. The results thus suggest an interaction of external supply, internal demand, and plant ability to acquire nutrients under different hydro-edaphic conditions that vary across this tree-height gradient. The findings not only aid in understanding

  7. Production of 15N-Labelled Liquid Organic Fertilisers Based on Manure and Crop Residue for Use in Fertigation Studies

    Science.gov (United States)

    Martínez-Alcántara, Belén; Martínez-Cuenca, Mary-Rus; Fernández, Carlos; Legaz, Francisco; Quiñones, Ana

    2016-01-01

    Large quantities of crop residue and animal manure from agricultural and livestock activities are annually produced worldwide. With proper management, these residues are potentially valuable sources of plant nutrients, mainly N. Recycling such subproducts in sustainably-based agricultural systems can minimise the use of mineral fertilisers, and hence reduce the potential risk of surface and groundwater pollution. Therefore, the purpose of this study was to obtain (small scale) two liquid labelled-organic fertilisers, an animal- and a vegetal-based organic (AO and VO, respectively) fertiliser, to be used as organic N sources in subsequent fertigation studies. Forage maize (Zea mays L.) grown under 15N-labelled fertiliser supply was used as raw material for VO fertiliser production, and also as 15N-labelled sheep feed to obtain 15N-labelled manure. The labelled faeces fraction was used as raw material for the AO fertiliser. The VO fertiliser was obtained after an acidic and an enzyme-driven hydrolysis. The AO fertiliser was obtained after acidic hydrolysis. The VO liquid fertiliser presented an N concentration of 330 mg·L-1, 85% of total N was organic, while ammonium and nitrate N accounted for 55% and 45% of the mineral nitrogen fraction, respectively. This fertiliser also exhibited high K, Ca and S concentrations and notable values for the remaining macro- and micronutrients. The AO liquid fertiliser had a similar total N concentration (496 mg·L-1, 82% of total N in an organic form) to that of VO, but its mineral N fraction significantly differed, which came in a predominantly (95%) ammonia form. It also had a high content of N, P, K and other macronutrients, and sufficient Fe, Zn, Mn, Cu and B levels, which suggests its suitability as a potential fertiliser. The percentage of 15N enrichment in both VO and AO liquid fertilisers exceeded 2% 15N atom excess, which enabled their use in subsequent assays run to assess nitrogen uptake efficiency. PMID:26982183

  8. Efficient production of (2)H, (13)C, (15)N-enriched industrial enzyme Rhizopus chinensis lipase with native disulfide bonds.

    Science.gov (United States)

    Zhang, Meng; Yu, Xiao-Wei; Swapna, G V T; Xiao, Rong; Zheng, Haiyan; Sha, Chong; Xu, Yan; Montelione, Gaetano T

    2016-07-13

    In order to use most modern methods of NMR spectroscopy to study protein structure and dynamics, isotope-enriched protein samples are essential. Especially for larger proteins (>20 kDa), perdeuterated and Ile (δ1), Leu, and Val methyl-protonated protein samples are required for suppressing nuclear relaxation to provide improved spectral quality, allowing key backbone and side chain resonance assignments needed for protein structure and dynamics studies. Escherichia coli and Pichia pastoris are two of the most popular expression systems for producing isotope-enriched, recombinant protein samples for NMR investigations. The P. pastoris system can be used to produce (13)C, (15)N-enriched and even (2)H,(13)C, (15)N-enriched protein samples, but efficient methods for producing perdeuterated proteins with Ile (δ1), Leu and Val methyl-protonated groups in P. pastoris are still unavailable. Glycosylation heterogeneity also provides challenges to NMR studies. E. coli expression systems are efficient for overexpressing perdeuterated and Ile (δ1), Leu, Val methyl-protonated protein samples, but are generally not successful for producing secreted eukaryotic proteins with native disulfide bonds. The 33 kDa protein-Rhizopus chinensis lipase (RCL), an important industrial enzyme, was produced using both P. pastoris and E. coli BL21 trxB (DE3) systems. Samples produced from both systems exhibit identical native disulfide bond formation and similar 2D NMR spectra, indicating similar native protein folding. The yield of (13)C, (15)N-enriched r27RCL produced using P. pastoris was 1.7 times higher that obtained using E. coli, while the isotope-labeling efficiency was ~15 % lower. Protein samples produced in P. pastoris exhibit O-glycosylation, while the protein samples produced in E. coli were not glycosylated. The specific activity of r27RCL from P. pastoris was ~1.4 times higher than that produced in E. coli. These data demonstrate efficient production of (2)H, (13)C, (15)N

  9. Production of 15N-Labelled Liquid Organic Fertilisers Based on Manure and Crop Residue for Use in Fertigation Studies.

    Directory of Open Access Journals (Sweden)

    Belén Martínez-Alcántara

    Full Text Available Large quantities of crop residue and animal manure from agricultural and livestock activities are annually produced worldwide. With proper management, these residues are potentially valuable sources of plant nutrients, mainly N. Recycling such subproducts in sustainably-based agricultural systems can minimise the use of mineral fertilisers, and hence reduce the potential risk of surface and groundwater pollution. Therefore, the purpose of this study was to obtain (small scale two liquid labelled-organic fertilisers, an animal- and a vegetal-based organic (AO and VO, respectively fertiliser, to be used as organic N sources in subsequent fertigation studies. Forage maize (Zea mays L. grown under 15N-labelled fertiliser supply was used as raw material for VO fertiliser production, and also as 15N-labelled sheep feed to obtain 15N-labelled manure. The labelled faeces fraction was used as raw material for the AO fertiliser. The VO fertiliser was obtained after an acidic and an enzyme-driven hydrolysis. The AO fertiliser was obtained after acidic hydrolysis. The VO liquid fertiliser presented an N concentration of 330 mg·L-1, 85% of total N was organic, while ammonium and nitrate N accounted for 55% and 45% of the mineral nitrogen fraction, respectively. This fertiliser also exhibited high K, Ca and S concentrations and notable values for the remaining macro- and micronutrients. The AO liquid fertiliser had a similar total N concentration (496 mg·L-1, 82% of total N in an organic form to that of VO, but its mineral N fraction significantly differed, which came in a predominantly (95% ammonia form. It also had a high content of N, P, K and other macronutrients, and sufficient Fe, Zn, Mn, Cu and B levels, which suggests its suitability as a potential fertiliser. The percentage of 15N enrichment in both VO and AO liquid fertilisers exceeded 2% 15N atom excess, which enabled their use in subsequent assays run to assess nitrogen uptake efficiency.

  10. The Effects of Computer Simulation and Animation (CSA) on Students' Cognitive Processes: A Comparative Case Study in an Undergraduate Engineering Course

    Science.gov (United States)

    Fang, N.; Tajvidi, M.

    2018-01-01

    This study focuses on the investigation of the effects of computer simulation and animation (CSA) on students' cognitive processes in an undergraduate engineering course. The revised Bloom's taxonomy, which consists of six categories in the cognitive process domain, was employed in this study. Five of the six categories were investigated,…

  11. Assessing the Long-Term Effects of EMDR: Results from an 18-Month Follow-Up Study with Adult Female Survivors of CSA

    Science.gov (United States)

    Edmond, Tonya; Rubin, Allen

    2004-01-01

    This 18-month follow-up study builds on the findings of a randomized experimental evaluation that found qualified support for the short-term effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) in reducing trauma symptoms among adult female survivors of childhood sexual abuse (CSA). The current study provides preliminary evidence…

  12. Differential evolution of anti-VAR2CSA- IgG3 in primigravidae and multigravidae pregnant women infected by Plasmodium falciparum

    DEFF Research Database (Denmark)

    Guitard, Juliette; Cottrell, Gilles; Magnouha, Nellie Moulopo

    2008-01-01

    in multigravidae. CONCLUSION: This high level of IgG3 in uninfected primigravidae suggests a protective role of these antibodies in this susceptible group, highlighting the importance of VAR2CSA in general and of some of its variants still to be defined, in the induction of protective immunity to pregnancy malaria....

  13. A transposable element insertion in the susceptibility gene CsaMLO8 results in hypocotyl resistance to powdery mildew in cucumber

    NARCIS (Netherlands)

    Berg, J.A.; Appiano, M.; Santillán Martínez, M.I.; Hemans, F.W.K.; Vriezen, W.H.; Visser, R.G.F.; Bai, Y.; Schouten, H.J.

    2015-01-01

    Background - Powdery mildew (PM) is an important disease of cucumber (Cucumis sativus L.). CsaMLO8 was previously identified as a candidate susceptibility gene for PM in cucumber, for two reasons: 1) This gene clusters phylogenetically in clade V, which has previously been shown to harbour all known

  14. Csa-19, a radiation-responsive human gene, identified by an unbiased two-gel cDNA library screening method in human cancer cells

    Science.gov (United States)

    Balcer-Kubiczek, E. K.; Meltzer, S. J.; Han, L. H.; Zhang, X. F.; Shi, Z. M.; Harrison, G. H.; Abraham, J. M.

    1997-01-01

    A novel polymerase chain reaction (PCR)-based method was used to identify candidate genes whose expression is altered in cancer cells by ionizing radiation. Transcriptional induction of randomly selected genes in control versus irradiated human HL60 cells was compared. Among several complementary DNA (cDNA) clones recovered by this approach, one cDNA clone (CL68-5) was downregulated in X-irradiated HL60 cells but unaffected by 12-O-tetradecanoyl phorbol-13-acetate, forskolin, or cyclosporin-A. DNA sequencing of the CL68-5 cDNA revealed 100% nucleotide sequence homology to the reported human Csa-19 gene. Northern blot analysis of RNA from control and irradiated cells revealed the expression of a single 0.7-kilobase (kb) messenger RNA (mRNA) transcript. This 0.7-kb Csa-19 mRNA transcript was also expressed in a variety of human adult and corresponding fetal normal tissues. Moreover, when the effect of X- or fission neutron-irradiation on Csa-19 mRNA was compared in cultured human cells differing in p53 gene status (p53-/- versus p53+/+), downregulation of Csa-19 by X-rays or fission neutrons was similar in p53-wild type and p53-null cell lines. Our results provide the first known example of a radiation-responsive gene in human cancer cells whose expression is not associated with p53, adenylate cyclase or protein kinase C.

  15. Acúmulo de nutrientes e destino do nitrogênio (15N aplicado em pomar jovem de laranjeira Nutrients accumulation and fate of nitrogen (15N in Young bearing orange trees

    Directory of Open Access Journals (Sweden)

    Rodrigo Marcelli Boaretto

    2007-01-01

    Full Text Available Informações sobre absorção de nutrientes em pomares cítricos são importantes para recomendações do manejo da fertilidade do solo. Contudo, estudos sobre a distribuição dos nutrientes na planta e a validação das doses de nitrogênio (N recomendadas são escassos na literatura brasileira. O presente trabalho avaliou (i o acúmulo de nutrientes e a distribuição do N (15N aplicado em citros e (ii validou a dose de N recomendada para pomares em início de produção. Em laranjeiras 'Pêra' sobre limoeiro 'Cravo', com 3 a 4 anos de idade, foram aplicadas doses de 150; 300; 450 e 600 g de N por planta, como sulfato de amônio, divididas em três parcelas, entre a primavera e o verão. Incluiu-se um tratamento-testemunha sem N. No mesmo pomar, em outras três plantas, aplicaram-se 300 g por planta de N-[(15NH42SO 4] enriquecido em 15N, para estudar o destino do N do fertilizante no pomar. Foram avaliadas a produção de frutos e o aproveitamento do 15N pela biomassa da planta. A eficiência do fertilizante, estimada com base na absorção de N pela planta, variou entre 20% e 27% do total aplicado. Os frutos exportaram 35% do N absorvido do fertilizante, e a dose de 400 g de N proporcionou a máxima produção de laranjas.Information about nutrient absorption of citrus orchards is important to establish guidelines for best soil fertility management. However, studies on the fate of applied N fertilizers and validation of nitrogen (N dose recommendations are scarce in the literature. The present work evaluated (i the accumulation of nutrients and the distribution of N (15N applied to citrus orchard and (ii validated the N fertilization rate applied to young bearing orange trees. Three- to four-year-old Pêra sweet orange trees Pera grafted on Rangpur lime were fertilized with 150, 300, 450, and 600 g of N per tree, as ammonium sulfate, split in three applications from spring to summer. A control treatment without N was included. In the same

  16. Residue-specific membrane location of peptides and proteins using specifically and extensively deuterated lipids and {sup 13}C-{sup 2}H rotational-echo double-resonance solid-state NMR

    Energy Technology Data Exchange (ETDEWEB)

    Xie Li; Ghosh, Ujjayini; Schmick, Scott D.; Weliky, David P., E-mail: weliky@chemistry.msu.edu [Michigan State University, Department of Chemistry (United States)

    2013-01-15

    Residue-specific location of peptides in the hydrophobic core of membranes was examined using {sup 13}C-{sup 2}H REDOR and samples in which the lipids were selectively deuterated. The transmembrane topology of the KALP peptide was validated with this approach with substantial dephasing observed for deuteration in the bilayer center and reduced or no dephasing for deuteration closer to the headgroups. Insertion of {beta} sheet HIV and helical and {beta} sheet influenza virus fusion peptides into the hydrophobic core of the membrane was validated in samples with extensively deuterated lipids.

  17. Nitrogen ({sup 15}N) accumulation in corn grains as affected by source of nitrogen in red latosol;Acumulo de nitrogenio ({sup 15}N) pelos graos de milho em funcao da fonte nitrogenada em latossolo vermelho

    Energy Technology Data Exchange (ETDEWEB)

    Duete, Robson Rui Cotrim, E-mail: rrcduete@oi.com.b [Empresa Baiana de Desenvolvimento Agricola S.A. (EBDA), Cruz das Almas, BA (Brazil); Muraoka, Takashi; Trivelin, Paulo Cesar Ocheuze; Silva, Edson Cabral da, E-mail: muraoka@cena.usp.b, E-mail: pcotrive@cena.usp.b, E-mail: ecsilva@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Ambrosano, Edmilson Jose, E-mail: ambrosano@aptaregional.sp.gov.b [Agencia Paulista de Tecnologia dos Agronegocios (APTA), Piracicaba, SP (Brazil). Polo Centro Sul

    2009-07-01

    Nitrogen is the most absorbed mineral nutrient by corn crop and most affects grains yield. It is the unique nutrient absorbed by plants as cation (NH{sub 4}{sup +}) or anion (NO{sub 3}{sup -}). The objectives of this work were to investigate the N accumulation by corn grains applied to the soil as NH{sub 4}{sup +} or NO{sub 3}{sup -} in the ammonium nitrate form compared to amidic form of the urea, labeled with {sup 15}N; to determine the corn growth stage with highest fertilizer N utilization by the grains, and to quantify soil nitrogen exported by corn grains. The study was carried out in the Experimental Station of the Regional Pole of the Sao Paulo Northwestern Agribusiness Development (APTA), in Votuporanga, State of Sao Paulo, Brazil, in a Red Latosol. The experimental design was completely randomized blocks, with 13 treatments and four replications, disposed in factorial outline 6x2 + 1 (control, without N application). A nitrogen rate equivalent to 120 kg N ha-1 as urea-{sup 15}N or as ammonium nitrate, labeled in the cation NH{sub 4}{sup +} ({sup 15}NH{sub 4}{sup +}NO{sub 3}{sup -}) or in the anion NO{sub 3}{sup -} (NH{sub 4}{sup +}15N+O{sub 3}{sup -} ), was applied in six fractions of 20 kg N ha-1 each, in different microplots, from seeding to the growth stage 7 (pasty grains). The forms of nitrogen, NH{sub 4}{sup +}-N and N{sub O}{sup 3}--N, were accumulated equitably by corn grains. The corn grains accumulated more N from urea than from ammonium nitrate. The N applied to corn crop at eight expanded leaves stage promoted largest accumulation of this nutrient in the grains. (author)

  18. Evaluation of (+)-p-[{sup 11}C]methylvesamicol for mapping sigma{sub 1} receptors: a comparison with [{sup 11}C]SA4503

    Energy Technology Data Exchange (ETDEWEB)

    Ishiwata, Kiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0022 (Japan)]. E-mail: ishiwata@pet.tmig.or.jp; Kawamura, Kazunori [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0022 (Japan); SHI Accelerator Service Ltd., Tokyo 141-0032 (Japan); Yajima, Kazuyoshi [The Medical and Pharmacological Research Center Foundation, Hakui 920-0631 (Japan); QingGeLeTu [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0022 (Japan); Mori, Hirofumi [Advanced Science Research Center, Kanazawa University, Kanazawa 920-8640 (Japan); Shiba, Kazuhiro [Advanced Science Research Center, Kanazawa University, Kanazawa 920-8640 (Japan)

    2006-05-15

    Vesamicol is a leading compound for positron emission tomography (PET) and single photon emission computed tomography (SPECT) tracers for mapping the vesicular acetylcholine transporter (VAChT). Recently, we found that (+)-p-methylvesamicol ((+)-PMV) has low affinity for VAChT (K {sub i}=199 nM), but has moderate to high affinity for sigma receptors: K {sub i}=3.0 nM for sigma{sub 1} and K {sub i}=40.7 nM for sigma{sub 2}, and that sigma{sub 1}-selective SA4503 (K {sub i}=4.4 nM for sigma{sub 1} and K {sub i}=242 nM for sigma{sub 2}) has moderate affinity for VAChT (K {sub i}=50.2 nM). In the present study, we examined the potential of (+)-[{sup 11}C]PMV as a PET radioligand for mapping sigma{sub 1} receptors as compared with [{sup 11}C]SA4503. In rat brain, similar regional distribution patterns of (+)-[{sup 11}C]PMV and [{sup 11}C]SA4503 were shown by tissue dissection and by ex vivo autoradiography. Blocking experiments using ({+-})-PMV (-)-vesamicol, SA4503, haloperidol and ({+-})-pentazocine showed that the two tracers specifically bound to sigma{sub 1} receptors, and that [{sup 11}C]SA4503 exhibited greater specific binding than (+)-[{sup 11}C]PMV. No sign of VAChT-specific binding by [{sup 11}C]SA4503 was observed in the striatum, which is rich in VAChT sites. In conclusion, (+)-[{sup 11}C]PMV specifically bound to sigma{sub 1} receptors in the brain, but to a lesser extent than [{sup 11}C]SA4503, suggesting that (+)-[{sup 11}C]PMV is a less preferable PET ligand than [{sup 11}C]SA4503. On the other hand, the moderate affinity of [{sup 11}C]SA4503 for VAChT is negligible in vivo.

  19. Compound-specific amino acid δ15N patterns in marine algae: Tracer potential for cyanobacterial vs. eukaryotic organic nitrogen sources in the ocean

    Science.gov (United States)

    McCarthy, Matthew D.; Lehman, Jennifer; Kudela, Raphael

    2013-02-01

    Stable nitrogen isotopic analysis of individual amino acids (δ15N-AA) has unique potential to elucidate the complexities of food webs, track heterotrophic transformations, and understand diagenesis of organic nitrogen (ON). While δ15N-AA patterns of autotrophs have been shown to be generally similar, prior work has also suggested that differences may exist between cyanobacteria and eukaryotic algae. However, δ15N-AA patterns in differing oceanic algal groups have never been closely examined. The overarching goals of this study were first to establish a more quantitative understanding of algal δ15N-AA patterns, and second to examine whether δ15N-AA patterns have potential as a new tracer for distinguishing prokaryotic vs. eukaryotic N sources. We measured δ15N-AA from prokaryotic and eukaryotic phytoplankton cultures and used a complementary set of statistical approaches (simple normalization, regression-derived fractionation factors, and multivariate analyses) to test for variations. A generally similar δ15N-AA pattern was confirmed for all algae, however significant AA-specific variation was also consistently identified between the two groups. The relative δ15N fractionation of Glx (glutamine + glutamic acid combined) vs. total proteinaceous N appeared substantially different, which we hypothesize could be related to differing enzymatic forms. In addition, the several other AA (most notably glycine and leucine) appeared to have strong biomarker potential. Finally, we observed that overall patterns of δ15N values in algae correspond well with the Trophic vs. Source-AA division now commonly used to describe variable AA δ15N changes with trophic transfer, suggesting a common mechanistic basis. Overall, these results show that autotrophic δ15N-AA patterns can differ between major algal evolutionary groupings for many AA. The statistically significant multivariate results represent a first approach for testing ideas about relative eukaryotic vs. prokaryotic

  20. Steroid hormones affect binding of the sigma ligand 11C-SA4503 in tumour cells and tumour-bearing rats

    International Nuclear Information System (INIS)

    Rybczynska, Anna A.; Elsinga, Philip H.; Sijbesma, Jurgen W.; Jong, Johan R. de; Vries, Erik F. de; Dierckx, Rudi A.; Waarde, Aren van; Ishiwata, Kiichi

    2009-01-01

    Sigma receptors are implicated in memory and cognitive functions, drug addiction, depression and schizophrenia. In addition, sigma receptors are strongly overexpressed in many tumours. Although the natural ligands are still unknown, steroid hormones are potential candidates. Here, we examined changes in binding of the sigma-1 agonist 11 C-SA4503 in C6 glioma cells and in living rats after modification of endogenous steroid levels. 11 C-SA4503 binding was assessed in C6 monolayers by gamma counting and in anaesthetized rats by microPET scanning. C6 cells were either repeatedly washed and incubated in steroid-free medium or exposed to five kinds of exogenous steroids (1 h or 5 min before tracer addition, respectively). Tumour-bearing male rats were repeatedly treated with pentobarbital (a condition known to result in reduction of endogenous steroid levels) or injected with progesterone. Binding of 11 C-SA4503 to C6 cells was increased (∝50%) upon removal and decreased (∝60%) upon addition of steroid hormones (rank order of potency: progesterone > allopregnanolone = testosterone = androstanolone > dehydroepiandrosterone-3-sulphate, IC 50 progesterone 33 nM). Intraperitoneally administered progesterone reduced tumour uptake and tumour-to-muscle contrast (36%). Repeated treatment of animals with pentobarbital increased the PET standardized uptake value of 11 C-SA4503 in tumour (16%) and brain (27%), whereas the kinetics of blood pool radioactivity was unaffected. The binding of 11 C-SA4503 is sensitive to steroid competition. Since not only increases but also decreases of steroid levels affect ligand binding, a considerable fraction of the sigma-1 receptor population in cultured tumour cells or tumour-bearing animals is normally occupied by endogenous steroids. (orig.)

  1. Steroid hormones affect binding of the sigma ligand {sup 11}C-SA4503 in tumour cells and tumour-bearing rats

    Energy Technology Data Exchange (ETDEWEB)

    Rybczynska, Anna A.; Elsinga, Philip H.; Sijbesma, Jurgen W.; Jong, Johan R. de; Vries, Erik F. de; Dierckx, Rudi A.; Waarde, Aren van [University of Groningen, Nuclear Medicine and Molecular Imaging, University of Groningen Medical Center, Groningen (Netherlands); Ishiwata, Kiichi [Tokyo Metropolitan Institute of Gerontology, Positron Medical Center, Tokyo (Japan)

    2009-07-15

    Sigma receptors are implicated in memory and cognitive functions, drug addiction, depression and schizophrenia. In addition, sigma receptors are strongly overexpressed in many tumours. Although the natural ligands are still unknown, steroid hormones are potential candidates. Here, we examined changes in binding of the sigma-1 agonist {sup 11}C-SA4503 in C6 glioma cells and in living rats after modification of endogenous steroid levels. {sup 11}C-SA4503 binding was assessed in C6 monolayers by gamma counting and in anaesthetized rats by microPET scanning. C6 cells were either repeatedly washed and incubated in steroid-free medium or exposed to five kinds of exogenous steroids (1 h or 5 min before tracer addition, respectively). Tumour-bearing male rats were repeatedly treated with pentobarbital (a condition known to result in reduction of endogenous steroid levels) or injected with progesterone. Binding of {sup 11}C-SA4503 to C6 cells was increased ({proportional_to}50%) upon removal and decreased ({proportional_to}60%) upon addition of steroid hormones (rank order of potency: progesterone > allopregnanolone = testosterone = androstanolone > dehydroepiandrosterone-3-sulphate, IC{sub 50} progesterone 33 nM). Intraperitoneally administered progesterone reduced tumour uptake and tumour-to-muscle contrast (36%). Repeated treatment of animals with pentobarbital increased the PET standardized uptake value of {sup 11}C-SA4503 in tumour (16%) and brain (27%), whereas the kinetics of blood pool radioactivity was unaffected. The binding of {sup 11}C-SA4503 is sensitive to steroid competition. Since not only increases but also decreases of steroid levels affect ligand binding, a considerable fraction of the sigma-1 receptor population in cultured tumour cells or tumour-bearing animals is normally occupied by endogenous steroids. (orig.)

  2. The effect of adaptive servo ventilation (ASV) on objective and subjective outcomes in Cheyne-Stokes respiration (CSR) with central sleep apnea (CSA) in heart failure (HF): A systematic review.

    Science.gov (United States)

    Yang, Hyunju; Sawyer, Amy M

    2016-01-01

    To summarize the current evidence for adaptive servo ventilation (ASV) in Cheyne-Stokes respiration (CSR) with central sleep apnea (CSA) in heart failure (HF) and advance a research agenda and clinical considerations for ASV-treated CSR-CSA in HF. CSR-CSA in HF is associated with higher overall mortality, worse outcomes and lower quality of life (QOL) than HF without CSR-CSA. Five databases were searched using key words (n = 234). Randomized controlled trials assessed objective sleep quality, cardiac, and self-reported outcomes in adults (≥18 years) with HF (n = 10). ASV has a beneficial effect on the reduction of central sleep apnea in adult patients with CSR-CSA in HF, but it is not be superior to CPAP, bilevel PPV, or supplemental oxygen in terms of sleep quality defined by polysomnography, cardiovascular outcomes, subjective daytime sleepiness, and quality of life. ASV is not recommended for CSR-CSA in HF. It is important to continue to refer HF patients for sleep evaluation to clearly discern OSA from CSR-CSA. Symptom management research, inclusive of objective and subjective outcomes, in CSR-CSA in HF adults is needed. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Stable isotope analysis (δ (13)C and δ (15)N) of soil nematodes from four feeding groups.

    Science.gov (United States)

    Melody, Carol; Griffiths, Bryan; Dyckmans, Jens; Schmidt, Olaf

    2016-01-01

    Soil nematode feeding groups are a long-established trophic categorisation largely based on morphology and are used in ecological indices to monitor and analyse the biological state of soils. Stable isotope ratio analysis ((13)C/(12)C and (15)N/(14)N, expressed as δ (13)C and δ (15)N) has provided verification of, and novel insights into, the feeding ecology of soil animals such as earthworms and mites. However, isotopic studies of soil nematodes have been limited to date as conventional stable isotope ratio analysis needs impractically large numbers of nematodes (up to 1,000) to achieve required minimum sample weights (typically >100 µg C and N). Here, micro-sample near-conventional elemental analysis-isotopic ratio mass spectrometry (μEA-IRMS) of C and N using microgram samples (typically 20 µg dry weight), was employed to compare the trophic position of selected soil nematode taxa from four feeding groups: predators (Anatonchus and Mononchus), bacterial feeders (Plectus and Rhabditis), omnivores (Aporcelaimidae and Qudsianematidae) and plant feeder (Rotylenchus). Free-living nematodes were collected from conventionally and organically managed arable soils. As few as 15 nematodes, for omnivores and predators, were sufficient to reach the 20 µg dry weight target. There was no significant difference in δ (15)N (p = 0.290) or δ (13)C (p = 0.706) between conventional and organic agronomic treatments but, within treatments, there was a significant difference in N and C stable isotope ratios between the plant feeder, Rotylenchus (δ (15)N = 1.08 to 3.22 mUr‰, δ (13)C = -29.58 to -27.87 mUr) and all other groups. There was an average difference of 9.62 mUr in δ (15)N between the plant feeder and the predator group (δ (15)N = 9.89 to 12.79 mUr, δ (13)C = -27.04 to -25.51 mUr). Isotopic niche widths were calculated as Bayesian derived standard ellipse areas and were smallest for the plant feeder (1.37 mUr(2)) and the predators (1.73 mUr(2)), but largest for

  4. Stable isotope analysis (δ13C and δ15N of soil nematodes from four feeding groups

    Directory of Open Access Journals (Sweden)

    Carol Melody

    2016-09-01

    Full Text Available Soil nematode feeding groups are a long-established trophic categorisation largely based on morphology and are used in ecological indices to monitor and analyse the biological state of soils. Stable isotope ratio analysis (13C/12C and 15N/14N, expressed as δ13C and δ15N has provided verification of, and novel insights into, the feeding ecology of soil animals such as earthworms and mites. However, isotopic studies of soil nematodes have been limited to date as conventional stable isotope ratio analysis needs impractically large numbers of nematodes (up to 1,000 to achieve required minimum sample weights (typically >100 µg C and N. Here, micro-sample near-conventional elemental analysis–isotopic ratio mass spectrometry (μEA–IRMS of C and N using microgram samples (typically 20 µg dry weight, was employed to compare the trophic position of selected soil nematode taxa from four feeding groups: predators (Anatonchus and Mononchus, bacterial feeders (Plectus and Rhabditis, omnivores (Aporcelaimidae and Qudsianematidae and plant feeder (Rotylenchus. Free-living nematodes were collected from conventionally and organically managed arable soils. As few as 15 nematodes, for omnivores and predators, were sufficient to reach the 20 µg dry weight target. There was no significant difference in δ15N (p = 0.290 or δ13C (p = 0.706 between conventional and organic agronomic treatments but, within treatments, there was a significant difference in N and C stable isotope ratios between the plant feeder, Rotylenchus (δ15N = 1.08 to 3.22 mUr‰, δ13C = –29.58 to –27.87 mUr and all other groups. There was an average difference of 9.62 mUr in δ15N between the plant feeder and the predator group (δ15N = 9.89 to 12.79 mUr, δ13C = –27.04 to –25.51 mUr. Isotopic niche widths were calculated as Bayesian derived standard ellipse areas and were smallest for the plant feeder (1.37 mUr2 and the predators (1.73 mUr2, but largest for omnivores (3.83 mUr2

  5. Characterization of Nitrogen Uptake Pattern in Malaysian Rice MR219 at Different Growth Stages Using 15N Isotope

    Directory of Open Access Journals (Sweden)

    Mohammad Mu’az Hashim

    2015-09-01

    Full Text Available Nitrogen (N use efficiency is usually less than 50%, and it remains a major problem in rice cultivation. Controlled release fertilizer (CRF technology is one of the well-known efforts to overcome this problem. The efficiency of CRF, however, is very much dependent on the timing of nutrient release. This study was conducted to determine the precise time of N uptake by rice as a guideline to develop efficient CRF. Fertilizer N uptake by rice at different growth stages was investigated by using 15N isotopic technique. Rice was planted in pots, with 15N urea as N source at the rate of 120 kg/hm2. Potassium and phosphorus were applied at the same rate of 50 kg/hm2. Standard agronomic practices were employed throughout the growing periods. Rice plants were harvested every two weeks until maturation at the 14th week and analyzed for total N and 15N content. Nitrogen derived from fertilizer was calculated. Total N uptake in plants consistently increased until the 11th week. After that, it started to plateau and finally declined. Moreover, N utilization by rice plants peaked at 50%, which occurred during the 11th week after transplanting. N derived from fertilizer in rice plants were in the range of 18.7% to 40.0% in all plant tissues. The remaining N was derived from soil. Based on this study, N release from CRF should complete by the 11th week after planting to ensure the maximum fertilizer N uptake by rice plants. Efficient CRF should contribute to higher N derived from fertilizer which also resultedin a higher total N uptake by rice plants, increasing the potential of rice to produce higher yield while at the same time of reducing loss.

  6. Saline irrigation water and its effect on N.use efficiency, growth and yield of Sorghum plant using 15N

    International Nuclear Information System (INIS)

    Abd El-Latteef, E.M.

    2010-01-01

    Series of pot experiments were conducted and randomly arranged under greenhouse conditions for evaluating the effect of irrigation with saline water (alternative source) in combination with different organic sources (amendments) i.e. leucaena plant residue (LU), Quail feces (QF) and chicken manure (ChM) added in different percentages against the mineral form (ammonium sulfate) either in ordinary or 15 N labeled (2 and 5% 15 N atom excess) forms, on sorghum growth and nutrients acquisition. Artificial saline water with different EC and SAR values was prepared at laboratory using computer program designed by the author with guiding of the designed Package named Artificial Saline Irrigation Water (ASIW) (Manual of Salinity Research Methods). In addition, proline acid was also sprayed (foliar) on leaves of sorghum plants at different concentrations. The experimental results indicated the positive effect of organic amendments, as compared to mineral fertilizer, and foliar application of proline acid on enhancement of plant growth and nutrient uptake. This phenomenon was pronounced under water salinity conditions. In this regard, increasing of water salinity levels induced reduction in plant growth as well as nutrients acquisition. Data of 14 N/ 15 N ratio analysis pointed out enhancement of N derived from mineral source as affected by organic amendments. At the same time, considerable amounts of N was derived from organic sources and utilized by plants. The superiority of organic sources on each others was fluctuated depending on interaction with water salinity levels and proline concentrations. In conclusion, organic additives and proline acid has an improvement effects especially under adverse condition of irrigation water salinity.

  7. Variations in natural abundances of 15N and 13C in potassium fed lentil plants grown under water stress

    International Nuclear Information System (INIS)

    Kurdali, F.; Al-Shammaa, M.

    2009-01-01

    The impact of two K-fertilizer treatments [K0 (0) and K1 (150 kg K 2 O/ha)] on dry matter production and N 2 fixation (Ndfa) by Lentil (Lens culinaris.) was evaluated in a pot experiment. The plants were also subjected to three soil moisture regimes starting from bud flower initiation stage to pod formation (low, 45-50%. Moderate, 55-60% and high 75-80% of field capacity, abbreviated as FC1, FC2 and FC3, respectively). The 15 N natural abundance technique (%δ 15 N) was employed to evaluate N 2 fixation using barley as a reference crop. Moreover, the carbon isotope discrimination (%Δ 13 C) was determined to assess factors responsible for crop performance variability in the different treatments. Water restriction occurring during the post-flowering period considerably affects growth and N 2 -fixation. However, K-fertilizer enhanced plant performance by overcoming water shortage influences. The delta 15 N values in lentils ranged from +0.67 to +1.36% depending on soil moisture and K-fertilizer treatments. Whereas, those of N 2 fixation and the reference plant were -0.45 and +2.94%, respectively. Consequently, Ndfa% ranged from 45 and 65%. Water stress reduced Δ 13 C values in the FC1K0 And FC1K1 treatments. However, K fertilizer enhanced the whole plants Δ 13 C along with dry matter yield and N 2 fixation. The water stressed plants amended with K (FC1K1) seemed to be the best treatment because of its highest pod yield, high N balance and N 2 -fixation with low consumption of irrigation water. This illustrates the ecological and economical importance of K-fertilizer in alleviating water stress occurring during the post-flowering period of lentil.(Authors)

  8. δ15N and nutrient stoichiometry of water, aquatic organisms and environmental implications in Taihu lake, China.

    Science.gov (United States)

    Tao, Yu; Dan, Dai; Kun, Lei; Chengda, He; Haibing, Cong; Guo, Fu; Qiujin, Xu; Fuhong, Sun; Fengchang, Wu

    2018-06-01

    Nitrogen pollution has become a worldwide problem and the source identification is important for the development of pertinent control measures. In this study, isotope end members (rain, nitrogen fertilizer, untreated/treated sewage), and samples (river water discharging to Taihu lake, lake water, aquatic organisms of different trophic levels) were taken during 2010-2015 to examine their δ 15 N values and nutrient stoichiometry. Results indicated that phytoplankton (primary producers), which directly take up and incorporate N from the lake water, had a similar δ 15 N value (14.1‰ ± 3.2) to the end member of treated sewage (14.0‰ ± 7.5), and the most frequently observed δ 15 N value in the lake water was 8-12‰, both indicating the dominant impact of the sewage discharge. Relationship analysis between N isotope value of nitrate and nitrate concentration indicated that different N cycling existed between the algae-dominated northwest lake (NW) and the macrophyte-dominated southeast lake (SE), which is a result of both impacts of river inputs and denitrification. Our nutrient stoichiometry analysis showed that the lake water had a significantly higher N:P ratio than that of algae (p economic development in the watershed further confirmed that the rapid population increase and urbanization have resulted in a great change in the N loading and source proportion. We suggest that although P control is necessary in terms of eutrophication control, N pollution control is urgent for the water quality and ecological recovery for Taihu lake. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Nitrous oxide emissions from soil amended with 15N-labelled urea with nitrification inhibitor (Nitrapyrin) and mulch

    Science.gov (United States)

    Khan, Aamir; Heiling, Maria; Zaman, Mohammad; Resch, Christian

    2017-04-01

    Nitrous oxide (N2O), one of the key greenhouse and ozone (O3) depleting gases, constitutes 7% of the anthropogenic greenhouse effect. Its global warming potential is 310 times higher than that of carbon dioxide (CO2) and 16 times than methane (CH4) over a 100-year period. To develop mitigation tools for N2O emissions, and to investigate the relationship between gross N transformation and N2O emission from soil, it is imperative to understand N2O emission from soils as influenced by N inputs, environmental conditions and farm management practices. The use of nitrification inhibitor such as Nitrapyrin and crop residues (mulch) may have a role in mitigating N2O losses from soil because of their effects on nitrification and denitrification. It prevents hydrolytic action on urea and keeps nitrogen in ammonium form. To determine the effects of urea applied with nitrification inhibitor and mulch on N2O emissions from soil, an incubation experiment was conducted under controlled moisture of 60% water filled pore space (WFPS) and temperature (20±2oC) conditions. Soil samples (0-20 cm soil depth) collected from an arable site were treated with 15N-labelled urea (5 atom %) at 150 kg N/ha rate. The 5 treatments including control, (urea, urea with Nitrapyrin (800 g/100 kg urea), urea with mulch (5 tons/ha) and urea with Nitrapyrin and mulch) were replicated 4 times using 500 ml glass jars. The N2O isotopic signature and the intramolecular distribution of 15N were measured by off-axis integrated cavity output spectroscopy (Los Gatos Research). The preliminary results showed that nitrification inhibitor (Nitrapyrin) can be used to distinguish between different pathways of N2O production from soil. In addition to the site preference of the 15N promises to be a helpful tool to determine the source of the generated N2O.

  10. The influence of tannin, pectin and polyethylene glycol on attachment of 15N-labelled rumen microorganisms to cellulose

    International Nuclear Information System (INIS)

    Bento, M.H.L.; Acamovic, T.; Makkar, H.P.S.

    2005-01-01

    The microbial attachment to and gas production from α-cellulose (Sigma; C-8002) without and with mimosa tannin (MT), pectin (P), polyethylene glycol (PEG), MT + P or MT + PEG, were investigated using the in vitro gas production system. Microbial attachment based on 15 N-labelled rumen microorganisms in the residual pellet after 24 h incubation was estimated, which varied from 113.7 to 161.3 μg 15 N per g residual pellet. C + MT had the lowest microbial attachment (P 2 = 0.84, P 15 N) in the residual pellet measured for C + MT (0.054) and C + MT + P (0.159), compared with the other treatments (0.32 for C; 0.34 for C + P; 0.33 for C + PEG; and 0.33 for C + MT + PEG). A MT concentration of 194 g/kg diet reduced microbial attachment and activity of rumen microorganisms in vitro. Polyethylene glycol counteracted the effect of MT on microbial attachment and activity. Pectin exerted a beneficial effect on attachment and fermentation in the initial hours of incubation. A ratio of pectin to MT of 1:1 improved microbial activity of C + MT but inhibition of microbial activity by MT remained at 24 h as indicated by the lower gas production of C + MT + P compared with the control. The results support the hypothesis that there is considerable interaction between tannins, microbes and non-starch-polysaccharides (NSP) in animal feeds and that these interactions may influence the functional ability of microbes in the gastrointestinal tract of animals. (author)

  11. Wheat Yield Production Grown on Sandy Soil as Fertilized by Different N-Sources Using 15N-Technique

    International Nuclear Information System (INIS)

    Ismail, M. M.; Soliman, S. M.; El-Akel, E. A.; El-Sherbieny, A. E.; Awad, E. A. M.

    2007-01-01

    A pot experiment was carried out to evaluate the ability of some plant residues to meet total N demand of wheat crop in sandy soil and their performance to reduce chemical N fertilizer requirements. Residue-N sources, i.e. soybean and wheat residues were compared to ammonium sulfate as inorganic N source as well as mixtures of residue-N sources and (NH 4 )SO 4 in ratios of (3:1), (1:1) and (1:3), respectively. The nitrogen application rate in all amended pots was kept at 100 mg N pot -1 . The obtained results could be summarized as follows: 1) ry weight of straw and grains of wheat crop was significantly increased this at the addition of nitrogen sources as a result of N-uptake increased. The highest value was observed at the application treatment ratios of (1:1) and (1:3) on the basis of (residue: ammonium sulfate), which can be arranged in this order: Soybean > wheat + soybean > wheat residues. 2) he value of N derived from residues (Ndfr) and fertilizer (Ndff), as well as 15N -recovery ratios can be arranged in this order: Ammonium sulfate > soybean residue > Soybean + wheat residue > wheat residue. 3) he values indicated that 15N -labelled soybean residue in combination with ordinary, ammonium sulfate at the ratios of (*25: 75) and (*50: 50), respectively was found to be effective on 15N -recovery ratios in the straw and grains of wheat crop. 4) he present study indicates that the entire N requirements of wheat crop cannot be met by the separate application of any residue-N source examined.

  12. Seasonal variation in nitrogen pools and 15N/13C natural abundances in different tissues of grassland plants

    Directory of Open Access Journals (Sweden)

    J. K. Schjoerring

    2012-05-01

    Full Text Available Seasonal changes in nitrogen (N pools, carbon (C content and natural abundance of 13C and 15N in different tissues of ryegrass plants were investigated in two intensively managed grassland fields in order to address their ammonia (NH3 exchange potential. Green leaves generally had the largest total N concentration followed by stems and inflorescences. Senescent leaves had the lowest N concentration, indicating N re-allocation. The seasonal pattern of the Γ value, i.e. the ratio between NH4+ and H+ concentrations, was similar for the various tissues of the ryegrass plants but the magnitude of Γ differed considerably among the different tissues. Green leaves and stems generally had substantially lower Γ values than senescent leaves and litter. Substantial peaks in Γ were observed during spring and summer in response to fertilization and grazing. These peaks were associated with high NH4+ rather than with low H+ concentrations. Peaks in Γ also appeared during the winter, coinciding with increasing δ15N values, indicating absorption of N derived from mineralization of soil organic matter. At the same time, δ13C values were declining, suggesting reduced photosynthesis and capacity for N assimilation. δ15N and δ13C values were more influenced by mean monthly temperature than by the accumulated monthly precipitation. In conclusion, ryegrass plants showed a clear seasonal pattern in N pools. Green leaves and stems of ryegrass plants generally seem to constitute a sink for NH3, while senescent leaves have a large potential for NH3 emission. However, management events such as fertilisation and grazing may create a high NH3 emission potential even in green plant parts. The obtained results provide input for future modelling of plant-atmosphere NH3 exchange.

  13. Nitrogen assimilation and short term retention in a nutrient-rich tidal freshwater marsh - a whole ecosystem 15N enrichment study

    NARCIS (Netherlands)

    Gribsholt, B.; Struyf, E.; Tramper, A.; de Brabandere, L.; Brion, N.; van Damme, S.; Meire, P.; Dehairs, F.; Middelburg, J.J.; Boschker, H.T.S.

    2007-01-01

    An intact tidal freshwater marsh system (3477 m2) was labelled by adding 15N-ammonium as a tracer to the flood water inundating the ecosystem. The appearance and retention of 15N-label in different marsh components (leaves, roots, sediment, leaf litter and invertebrate fauna) was followed over 15

  14. The use of 15N-labeled dietary proteins for determining true ileal amino acid digestibilities is limited by their rapid recycling in the endogenous secretions of pigs

    NARCIS (Netherlands)

    Leterme, P.; Théwis, A.; François, E.; Leeuwen, P. van; Wathelet, B.; Huisman, J.

    1996-01-01

    We assessed the use of 15N-labeled dietary proteins as a possible tool for the determination of the true ileal amino acid (AA) digestibility in pigs. The first experiment was designed to study the dietary N excretion pattern at the ileum subsequent to the ingestion of a single 15N-labeled meal. In a

  15. Variability of δ15N in soil and plants at a New Zealand hill country site: correlations with soil chemistry and nutrient inputs

    International Nuclear Information System (INIS)

    Hawke, D.J.

    2000-01-01

    This study investigated 15 N enrichment and nutrient cycling in hill country used for semi-extensive pastoral agriculture, at a site where pre-European seabird breeding occurred. Soil (>15 cm) and plant samples were taken from 18 ridgeline and sideslope transects. Three stock camps (locations which grazing animals frequent) were identified within the study area, two on the ridgeline and one on the sideslope. Soil 15 N enrichment was greatest at stock camps, and lowest where stock input was minimal. Soil natural abundance 15 N (815N) was therefore an index of stock nutrient inputs. Soil δ 15 N increased with decreasing C:N ratio, consistent with N loss through volatilisation and/or nitrate leaching from net mineralisation. Plant δ 15 N from stock camps was lower than its associated soil, implying that 15 N enrichment of plant-available N was lower than that of total soil N. However, the correlation between plant δ 15 N and soil δ 15 N varied between stock camps, indicating differences in N cycling. Olsen P was higher at stock camps, although again differences were found between stock camps. Total P and N were correlated neither with stock camps nor topography, but were higher than expected from parent material concentrations and literature results, respectively. It is postulated that significant contributions of both elements from former seabird breeding remain in the soil. Copyright (2000) CSIRO Publishing

  16. Patterns in δ15N in roots, stems, and leaves of sugar maple and American beech seedlings, saplings, and mature trees

    Science.gov (United States)

    L.H. Pardo; P. Semaoune; P.G. Schaberg; C. Eagar; M. Sebilo

    2013-01-01

    Stable isotopes of nitrogen (N) in plants are increasingly used to evaluate ecosystem N cycling patterns. A basic assumption in this research is that plant δ15N reflects the δ15N of the N source. Recent evidence suggests that plants may fractionate on uptake, transport, or transformation of N. If the...

  17. Nitrogen incorporation and retention by bacteria, algae, and fauna in a subtropical, intertidal sediment: An in situ 15N-labeling study

    NARCIS (Netherlands)

    Veuger, B.; Eyre, B.D.; Maher, D.; Middelburg, J.J.

    2007-01-01

    We performed a 15N-labeling study to investigate nitrogen incorporation and retention by the benthic microbial community (bacteria and benthic microalgae) and fauna in the intertidal sediment of the subtropical Australian Brunswick Estuary. The main experiment involved an in situ 15N pulse–chase

  18. Abundance of 13C and 15N in emmer, spelt and naked barley grown on differently manured soils: towards a method for identifying past manuring practice

    DEFF Research Database (Denmark)

    Kanstrup, Marie; Thomsen, Ingrid Kaag; Andersen, Astrid Junker

    2011-01-01

    fractions of the ancient cereal types; differences in δ15N between unmanured and PK treatments were insignificant. The offset in straw and grain δ15N due to manure averaged 7.9 and 8.8 ‰, respectively, while the soil offset was 1.9 ‰. The soil and biomass δ13C values were not affected by nutrient amendments...

  19. d13C vs d15N of co-occurring molluscs within a community dominated by Crassostrea gigas and Crepidula fornicata (Oosterschelde, The Netherlands)

    NARCIS (Netherlands)

    Riera, P.; Stal, L.J.; Nieuwenhuize, J.

    2002-01-01

    The aim of this study was to investigate, by use of d13C and d15N, the diet of co-occurring intertidal molluscs species within a community dominated by the oyster Crassostrea gigas and its epibiont, the common Atlantic slipper limpet Crepidula fornicata. The results showed that the d13C versus d15N

  20. Proton NMR measurements of bacteriophage T4 lysozyme aided by 15N isotopic labeling: structural and dynamic studies of larger proteins

    International Nuclear Information System (INIS)

    McIntosh, L.P.; Griffey, R.H.; Muchmore, D.C.; Nielson, C.P.; Redfield, A.G.; Dahlquist, F.W.

    1987-01-01

    A strategy for resolution and assignment of single proton resonances in proteins of molecular mass up to at least 40 kDa is presented. This approach is based on 15 N (or 13 C) labeling of selected residues in a protein. The resonances from protons directly bonded to labeled atoms are detected in a two-dimensional 1H- 15 N (or 13 C) spectrum. The nuclear Overhauser effects from isotopically tagged protons are selectively observed in one-dimensional isotope-directed measurements. Using this approach, we have observed approximately 160 resonances from 15 N-bonded protons in the backbone and sidechains of uniformly 15 N-labeled T4 lysozyme (molecular mass = 18.7 kDa). Partial proton-deuterium exchange can be used to simplify the 1H- 15 N spectrum of this protein. These resonances are identified by amino acid class using selective incorporation of 15 N-labeled amino acids and are assigned to specific residues by mutational substitution, multiple 15 N and 13 C labeling, and isotope-directed nuclear Overhauser effect measurements. For example, using a phenyl[ 15 N]alanine-labeled lysozyme variant containing two consecutive phenylalanine residues in an alpha-helical region, we observe an isotope-directed nuclear Overhauser effect from the amide proton of Phe-66 to that of Phe-67

  1. Nuclear astrophysics deep underground the case of the 15N(p,γ)16O reaction at LUNA

    CERN Document Server

    Mazzocchi, Chiara

    2010-01-01

    Measuring nuclear reactions of astrophysical interest at the relevant energies is not always possible on the Earth’s surface because of the cosmic-ray background that dominates the spectra. The LUNA collaboration exploits the lowbackground enviroment of Gran Sasso National Laboratory to study these reactions at or close to the Gamow peak. The latest experimental efforts included the measurement of the 15N(p,γ)16O at beam energies between 77 and 350 keV. The status of these measurements is summarised in this contribution.

  2. Transfer Comparison Study Nitrogen on the Intact and Decapitated Legumes by Using the 15N Labeling Technique

    International Nuclear Information System (INIS)

    Widjayanto, Didik W.

    1998-01-01

    The experiment was done in order to evaluate the N transfer from the intact and decapitated legumes by using the 15 N labeling technique. Seven days after final labeling the above ground biomass from labeled legume species was removed and the remaining stalks capped to prevent regrowth. Twenty days after final labeling (fourteen days after capping) the all treatments were sample and analyzed. The decapitated legumes appeared to transfer more percentage N than the intact legumes. Although both decapitated and intact legumes transferred, the transfer of N did not incur a dry matter and N yield benefit

  3. The study on effect of zeolite on nitrogen use efficiency of corn by 15N-isotope dilution method

    International Nuclear Information System (INIS)

    Li Changhong; Li Huaxing; Zhang Xinming; Liu Yuanjin

    2002-01-01

    A pot experiment was carried out to study the effect of natural zeolite on nitrogen use efficiency of corn by using 15 N-isotope dilution method. The results showed that application of zeolite could improve the corn growth and enhance the biomass of the corn seedling. By using zeolite, nitrogen use efficiency (NUE) of corn was increased by 23.2%-33.1% as compared with no-zeolite treatment; and the residual nitrogen has no significant difference between zeolite treatment and no-zeolite treatment

  4. Impact of charring on cereal grain characteristics: linking prehistoric manuring practice to 15N signatures in archaeobotanical material

    DEFF Research Database (Denmark)

    Kanstrup, Marie; Thomsen, Ingrid Kaag; Mikkelsen, Peter Hambro

    2012-01-01

    Systematic use of animal manure has been demonstrated to be detectable in the plant δ15N value but evidence of manure affecting isotopic composition is mainly based on studies of fresh plant material. These findings can potentially be applied to archaeobotanical assemblages and thus provide...... information about prehistoric manuring practice. Prehistoric grains are generally found in a charred state of which the exact charring conditions are unknown but most likely often multifarious. In this study we examined the influence of grain weight and a range of charring conditions with regards duration...

  5. Measuring the BNF of Soybean Using 15N-Labelled Urea with Different Atom Excess (A.E.) Content

    International Nuclear Information System (INIS)

    Citraresmini, A.; Halim, H.; Sisworo, E.L.

    2012-01-01

    The soybean is a legume which has an ability to supply its major nitrogen need by the biological nitrogen fixation (BNF) process. This process is made possible by nodules formed in their roots, colonized by Rhizobium sp.bacteria. An accurate estimation of N gained by BNF is necessary to predict the increase or decrease of chemical fertilizer-N requirements to increase soybean production. Among several methods, the 15 N method was used to estimate the ability of legumes to perform BNF. The study involved soybean var. Willis (W) and a completely non-BNF soybean var. CV, which is termed as a standard crop. The standard crop is non-nodulated soybean, but it has the same main physiological traits with var. Willis. The aim of this study was to determine whether 15 N-labelled fertilizer with different %a.e. given to nodulated and non-nodulated soybean would not be of significant consequences for the calculation of N-BNF of W. The treatments applied were different rates of urea (20 kg N/ha and 100 kg N/ha) combined with different atom excess percentages (%a.e.) 15 N (2% and 10%). Thus, the combination of treatments were as follows:(1) W-11 (20 kg N; 2% a.e); (2) CV-hl (100 kg N; 2% a.e); (3) W-lh (20 kg N; 10% a.e); (4) CV-hh (100 kg N; 10% a.e); (5) CV-11 (20 kg N; 2% a.e); (6) W-hl (100 kg N; 2% a.e); (7) CV-lh (20 kg N; 10% a.e); (8) W-hh (100 kg N; 10% a.e). The result of the experiment showed that a high %a.e. with a low rate of 15 N and a low %a.e. with a high rate of N should be used to study the %N-BNF of nodulated plants. (author)

  6. Measurement of the denitrification in soil monoliths from grassland and arable soil by means of 15N techniques

    International Nuclear Information System (INIS)

    Lippold, H.; Foerster, I.

    1980-01-01

    Losses of fertilizer nitrogen by denitrification were determined in soil monoliths from two sites (loess chernozem and clay ranker). The monoliths were isolated by driving plastic pipes into the plots, and fertilized with 15 N-labelled ammonium nitrate. Emission spectrometric techniques were applied to measure the N 2 and N 2 O quantities released in the isolated atmospheric layer above the monolith. The considerable losses, especially on grassland soils (up to a maximum of 30 kg N/ha), indicate the influence of rainfalls and mean temperature at the 5 dates of sampling (end of March to mid-October). (author)

  7. Oxygen 18 concentration profile measurements near the surface by 18O(p,α)15N resonance reaction

    International Nuclear Information System (INIS)

    Amsel, G.; David, D.

    1975-01-01

    The method of spectrum reduction in nuclear reaction microanalysis does not allow to obtain depth resolutions better than the order of 2000A. Resolutions of the order of 200A may be obtained by using the narrow resonance technique, when applied to thin films. The latter technique was extended to thick targets, with deep concentration profiles presenting a sharp gradient near the surface. This method is presented and illustrated by the study of 18 O profiles in oxygen diffusion measurements in growing ZrO 2 , using the 629keV resonance of the reaction 18 O(p,α) 15 N [fr

  8. Distribution Of 15N Fertilizer Added To Sandy Soil Under Drip Irrigation System As Affected By Irrigation Frequencies

    International Nuclear Information System (INIS)

    GADALLA, A.M.; GALAL, Y.G.M.; EL-GENDY, R.W.; ISMAIL, M.M.; EL-DEGWY, S.M.; KASSAB, M.F.

    2009-01-01

    Neutron moisture meter and stable nitrogen isotope ( 15 N) were used to follow horizontal and vertical water movement and N-fertilizer added to soil before and after irrigation. The data indicated that soil moisture distribution and values of total hydraulic potential depend on soil moisture content. Characterization of nitrogen in soil for all sites around the emitter indicated spatial variability with different soil depths due to leaching and volatilization processes. Moreover, water movement and flow direction greatly were characterized by active evaporation depth which was 30 cm.

  9. A new technique for the evaluation of the capacity of the gastrointestinal tract to assimilate foods by using a stable isotope of nitrogen (15N)

    International Nuclear Information System (INIS)

    Takemiya, Muneyasu; Fujita, Yoshikuni; Yazima, Yoshitada; Okabe, Haruya

    1983-01-01

    A new technique is introduced for the evaluation of the capacity of the gastrointestinal tract to assimilate foods by using a stable isotope of nitrogen ( 15 N) as a tracer. Four groups of male Wistar rats were fed 15 N-labeled rice for one day following a basal diet, composed of 87% poudered rice. Then, 15 N-labeled rice was switched to basal diet again for the next seven days. The four groups of rats consisted of: Group A-three pancreatic duct-ligated rats; Group B-four sham operated rats; Group C-five control rats and Group D-seven Streptozotocin-treated (20mg/kg) rats. The 15 N contents were measured in the stool, urine and sera collected before feeding of 15 N-labeled rice and one, three and seven days thereafter. In group A, the rate of 15 N excretion into the stools, i.e., the amount of 15 N in the stools against the total amount of 15 N consumed, was higher as compared to the control group throughout the period of the study. On the contrary, the rate of urinary excretion of 15 N as well as the contents of 15 N in the urine and sera were apparently lower. In group D, the rate of 15 N excretion into the stools as well as the contents of 15 N in the sera and urine showed no difference as compared to the control group. The rate of 15 N excretion into the urine, however, was apparently higher than that of the control group throughout the period of the study. These results indicate that this stable isotope of nitrogen ( 15 N), which clearly reveals the existence of malabsorption of pancreatic origin, is valuable as a tracer for assimilation studies and technically applicable for clinical use. We have found no evidence of malassimilation in rats with Streptozotocin-induced diabetes in spite of the presence of previous reports that assert the existence of pancreatic exocrine dysfunction in these animals. (author)

  10. PENGGUNAAN BRUTE FORCE ATTACK DALAM PENERAPANNYA PADA CRYPT8 DAN CSA-RAINBOW TOOL UNTUK MENCARI BISS

    Directory of Open Access Journals (Sweden)

    Indra Gunawan

    2016-09-01

    Full Text Available Algoritma Brute Force merupakan suatu aritmatika untuk mencari dan mengetahui sebuah jenis sandi atau kode yang salh satunya sebuah kode acakan misalnya jenis acakan BISS (Basic Interoperable Scrambling System. Algoritma brute force yang umumnya dipakai untuk mencari kasus kode acakan seperti ini umumnya disebut Brute Force Attack.    Brute force attack menggunakan sebuah himpunan karakter atau teks yang akan dipakai untuk referensi karakter-karakter dari kode yang ingin dicari. Himpunan karakter yang dipakai akan menjadi sebuah ukuran keefektifan dari algoritma itu sendiri. Semakin banyak anggota himpunan karakter ini, tentunya persentasi kode biss untuk sebuah kode biss dapat dicari akan tinggi. Namun, semakin banyak karakter yang ada di dalam himpunan itu harus dibayar dengan waktu pengerjaan yang lebih lama. Brute Force ini sudah mulai dikembangkan untuk mencari kode. Salah satu pengembangannya adalah pengumpulan chain sebagai database dan penggunaan Crypt8 dan CSA-Rainbow Tool yang menggunakan algoritma brute force sehingga memungkinkan untuk memangkas waktu yang diperlukan Brute Force Attack.

  11. Variation of natural 15N abundance of crops and soils in Japan with special reference to the effect of soil conditions and fertilizer application

    International Nuclear Information System (INIS)

    Yoneyama, Tadakatsu; Kouno, Kazumi; Yazaki, Jinya.

    1990-01-01

    The natural 15 N abundance (δ 15 N) of the crops subjected to long-term fertilizer treatments under paddy and upland conditions in the different experimental stations throughout Japan were analyzed. The δ 15 N values of the grains of paddy rice which were +6.3 per mille on the average in the fields without application of chemical fertilizers decreased by the treatment with chemical fertilizers. The average δ 15 N values of the upland crops were lower than those of paddy rice without application of N fertilizers. The δ 15 N values of upland crops decreased with the dose of chemical fertilizer N, but increased with the application of composts containing animal feces. The pot experiments using three soils showed that the δ 15 N values of paddy rice were higher than those of upland rice and sorghum and that these values were comparable to the δ 15 N values of ammonium and nitrate produced in the incubated soils, respectively. The δ 15 N values of fertilizer N absorbed by paddy rice were higher than those of fertilizer N, whereas the δ 15 N values of the fertilizer N in upland rice and sorghum were increased in the alluvial soils but decreased in Andosols as compared to those of fertilizer N applied. The δ 15 N values of the Andosols in Japan showed small variations, with an average value of +6.5 per mille, whereas those of alluvial soils in Japan showed large variations with an average value lower than that of Andosols. (author)

  12. Compound-specific 15N stable isotope probing of N assimilation by the soil microbial biomass: a new methodological paradigm in soil N cycling

    Science.gov (United States)

    Charteris, A. F.; Knowles, T. D. J.; Michaelides, K.; Evershed, R. P.

    2015-10-01

    A compound-specific nitrogen-15 stable isotope probing (15N-SIP) technique is described which allows investigation of the fate of inorganic- or organic-N amendments to soils. The technique uses gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) to determine the δ15N values of individual amino acids (AAs; determined as N-acetyl, O-isopropyl derivatives) as proxies of biomass protein production. The δ15N values are used together with AA concentrations to quantify N assimilation of 15N-labelled substrates by the soil microbial biomass. The utility of the approach is demonstrated through incubation experiments using inorganic 15N-labelled substrates ammonium (15NH4+) and nitrate (15NO3-) and an organic 15N-labelled substrate, glutamic acid (15N-Glu). Assimilation of all the applied substrates was undetectable based on bulk soil properties, i.e. % total N (% TN), bulk soil N isotope composition and AA concentrations, all of which remained relatively constant throughout the incubation experiments. In contrast, compound-specific AA δ15N values were highly sensitive to N assimilation, providing qualitative and quantitative insights into the cycling and fate of the applied 15N-labelled substrates. The utility of this 15N-AA-SIP technique is considered in relation to other currently available methods for investigating the microbially-mediated assimilation of nitrogenous substrates into the soil organic N pool. This approach will be generally applicable to the study of N cycling in any soil, or indeed, in any complex ecosystem.

  13. Estimation of N2-fixation in cowpea grown in monoculture or in mixture with maize using 15 N

    International Nuclear Information System (INIS)

    Shammaa, Mouhammad; Kurd Ali, Fawaz

    1994-01-01

    A pot experiment was carried out under natural climatic conditions to determine the proportion of different nitrogen sources (air, soil, fertilizer) in cowpea and maize grown alone or in mixture using 15 N isotope dilution technique. On average, the proportion of N derived from fixation by cowpea grown in mixed culture was 55% lower than that derived by the sole cropped cowpea (77%). Dry matter produced by one plant of maize grown in mixed culture was twice as much as that produced by a plant grown in mono culture. Moreover, total nitrogen content in one maize plant grown in mixed culture was 213 mg higher than that determined by two plant of maize grown in mono culture (171 mg). However, the amount of nitrogen derived from soil by maize grown in mixed culture was equal or even higher than that taken up by two plants of maize grown in mono culture. This indicates a better utilization of soil N by the maize in mixed culture. This data emphasize the crucial role of interspecific competition in soil N uptake. Data from this study do not support the hypothesis of N transfer from the legume to the cereal because no significant differences were found between mixed and pure maize in terms of 15 N in excess content. (author). 9 refs., 1 tab

  14. Characterising ontogenetic niche shifts in Nile crocodile using stable isotope (δ13C, δ15N) analyses of scute keratin.

    Science.gov (United States)

    Radloff, Frans G T; Hobson, Keith A; Leslie, Alison J

    2012-09-01

    Nile crocodiles undergo a three to five order of magnitude increase in body size during their lifespan. This shift coincides with a change in resource and habitat use which influences the strength, type and symmetry of interactions with other species. Identifying size-specific crocodile groups displaying similar traits is important for conservation planning. Here, we illustrate how stable carbon (δ(13) C) and nitrogen (δ(15) N) isotope analysis of scute keratin, together with breakpoint modelling analysis can be used to characterise ontogenetic niche shifts. Using a sample set of 238 crocodiles from the Okavango Delta, Botswana (35-463 cm total length), we found prominent size-related changes in the scute keratin δ(13) C and δ(15) N profiles close to 40 and 119 cm snout-vent length. The first shift corroborated the findings of a traditional stomach-content study conducted on the same population at the same time, and the second conformed to known crocodile ecology. This approach can be used as a first approximation to identify size-specific groups within crocodile populations, and these can then be investigated further using isotopic or other methods.

  15. Distribution of nitrogen ammonium sulfate (15N) soil-plant system in a no-tillage crop succession

    International Nuclear Information System (INIS)

    Fernandes, Flavia Carvalho da Silva; Libardi, Paulo Leonel

    2012-01-01

    the n use by maize (Zea mays, l.) is affected by n-fertilizer levels. this study was conducted using a sandy-clay texture soil (Hapludox) to evaluate the efficiency of n use by maize in a crop succession, based on 15 N labeled ammonium sulfate (5.5 atom %) at different rates, and to assess the residual fertilizer effect in two no-tillage succession crops (signal grass and corn). Two maize crops were evaluated, the first in the growing season 2006, the second in 2007, and brachiaria in the second growing season. The treatments consisted of n rates of 60, 120 and 180 kg ha -1 in the form of labeled 15 N ammonium sulfate. This fertilizer was applied in previously defined subplots, only to the first maize crop (growing season 2006). The variables total accumulated n; fertilizer-derived n in corn plants and pasture; fertilizer-derived n in the soil; and recovery of fertilizer-n by plants and soil were evaluated.The highest uptake of fertilizer n by corn was observed after application of 120 kg ha -1 N and the residual effect of n fertilizer on subsequent corn and brachiaria was highest after application of 180 kg ha -1 N. After the crop succession, soil n recovery was 32, 23 and 27 % for the respective applications of 60, 120 and 180 kg ha -1 N. (author)

  16. Traceability of animal meals in Japanese quail eggs using the technique of 13C e 15N* stable isotopes

    Directory of Open Access Journals (Sweden)

    C Mori

    2013-03-01

    Full Text Available The objective of this study was to trace the inclusion of bovine meat and bone meal (BMBM in the diet of Japanese quails by analyzing eggs and egg fractions (yolk and albumen by the technique of carbon-13 (13C and nitrogen-15 (15N stable isotopes. In the trial, 120 Japanese quails were distributed in six treatments with four replicates of five birds each. The following treatments were applied: feed based on corn and soybean meal, containing graded BMBM inclusions (0, 1, 2, 3, 4 or 5%. After 42 days, 20 eggs per treatment were randomly collected for three consecutive days. Ten eggs were used for yolk and albumen sample collection, and ten for total egg sample collection. It was possible to detect the dietary inclusion of 1% BMBM in the egg and its fractions. Therefore, the technique of isotopes 13C and 15N is able of tracing since 1% inclusion level of BMBM in the diet of Japanese quails in eggs and their fractions.

  17. 1H, 15N and 13C backbone resonance assignments of pentaerythritol tetranitrate reductase from Enterobacter cloacae PB2.

    Science.gov (United States)

    Iorgu, Andreea I; Baxter, Nicola J; Cliff, Matthew J; Waltho, Jonathan P; Hay, Sam; Scrutton, Nigel S

    2018-04-01

    Pentaerythritol tetranitrate reductase (PETNR) is a flavoenzyme possessing a broad substrate specificity and is a member of the Old Yellow Enzyme family of oxidoreductases. As well as having high potential as an industrial biocatalyst, PETNR is an excellent model system for studying hydrogen transfer reactions. Mechanistic studies performed with PETNR using stopped-flow methods have shown that tunneling contributes towards hydride transfer from the NAD(P)H coenzyme to the flavin mononucleotide (FMN) cofactor and fast protein dynamics have been inferred to facilitate this catalytic step. Herein, we report the near-complete 1 H, 15 N and 13 C backbone resonance assignments of PETNR in a stoichiometric complex with the FMN cofactor in its native oxidized form, which were obtained using heteronuclear multidimensional NMR spectroscopy. A total of 97% of all backbone resonances were assigned, with 333 out of a possible 344 residues assigned in the 1 H- 15 N TROSY spectrum. This is the first report of an NMR structural study of a flavoenzyme from the Old Yellow Enzyme family and it lays the foundation for future investigations of functional dynamics in hydride transfer catalytic mechanism.

  18. Resolving mass spectral overlaps in atom probe tomography by isotopic substitutions - case of TiSi15N.

    Science.gov (United States)

    Engberg, David L J; Johnson, Lars J S; Jensen, Jens; Thuvander, Mattias; Hultman, Lars

    2018-01-01

    Mass spectral overlaps in atom probe tomography (APT) analyses of complex compounds typically limit the identification of elements and microstructural analysis of a material. This study concerns the TiSiN system, chosen because of severe mass-to-charge-state ratio overlaps of the 14 N + and 28 Si 2+ peaks as well as the 14 N 2 + and 28 Si + peaks. By substituting 14 N with 15 N, mass spectrum peaks generated by ions composed of one or more N atoms will be shifted toward higher mass-to-charge-state ratios, thereby enabling the separation of N from the predominant Si isotope. We thus resolve thermodynamically driven Si segregation on the nanometer scale in cubic phase Ti 1- x Si x 15 N thin films for Si contents 0.08 ≤ x ≤ 0.19 by APT, as corroborated by transmission electron microscopy. The APT analysis yields a composition determination that is in good agreement with energy dispersive X-ray spectroscopy and elastic recoil detection analyses. Additionally, a method for determining good voxel sizes for visualizing small-scale fluctuations is presented and demonstrated for the TiSiN system. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Use of 15N dilution method for screening soybean lines with high yield and high nitrogen fixation ability

    International Nuclear Information System (INIS)

    Li Haixian; Li Xinmin; Danso, S.K.A.

    1998-01-01

    15 N dilution method was used for screening soybean lines with high nitrogen fixation ability. Screened lines 1005, 8502, 2096, 943, 1454 and Dongnong-42 have high nitrogen fixation ability with their % Ndfa of about 70%. 1454 and 1555 are both high yield and high nitrogen fixation lines. The ability of nitrogen fixation was not related to the yield, but related to maturing time. The cultivars with different maturing time have different levels of nitrogen fixation ability. The longer the maturing period is, the greater the ability of nitrogen fixation it has. There were ten cultivars or lines used in the test of 1992 and 1994. Although the weather condition were greatly different between the two years the results of seven cultivars or lines were the same, indicating that nitrogen fixation ability of the soybean is stable with years. Using 15 N dilution method to estimate nitrogen fixation ability of soybean is reliable, however, the % Ndfa of lines 8502 and 2096 increased by 19% in 1994, a rainy year, indicating that a change in % Ndfa with a few varieties maybe caused by weather

  20. Rapid NMR-scale purification of15N,13C isotope-labeled recombinant human STIM1 coiled coil fragments.

    Science.gov (United States)

    Rathner, Petr; Stadlbauer, Michael; Romanin, Christoph; Fahrner, Marc; Derler, Isabella; Müller, Norbert

    2018-02-01

    We report a new NMR-scale purification procedure for two recombinant wild type fragments of the stromal interaction molecule 1 (STIM1). This protein acts as a calcium sensor in the endoplasmic reticulum (ER) and extends into the cytosol accumulating at ER - plasma membrane (PM) junctions upon calcium store depletion ultimately leading to activation of the Orai/CRAC channel. The functionally relevant cytosolic part of STIM1 consists of three coiled coil domains, which are mainly involved in intra- and inter-molecular homomeric interactions as well as coupling to and gating of CRAC channels. The optimized one-step rapid purification procedure for two 15 N, 13 C isotope-labeled cytosolic coiled coil fragments, which avoids the problems of previous approaches. The high yields of soluble well folded 15 N, 13 C isotope-labeled cytosolic coiled coil fragments followed by detergent screening provide for initial NMR characterization of these domains. The longer 30.5 kDa fragment represents the largest STIM1 wild type fragment that has been recombinantly prepared and characterized in solution without need for mutation or refolding. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.