WorldWideScience

Sample records for active nitrogen species

  1. Nitrogen species

    Science.gov (United States)

    Harries, J. E.; Brasseur, G.; Coffey, M. T.; Fischer, H.; Gille, J.; Jones, R.; Louisnard, N.; McCormick, M. P.; Noxon, J.; Owens, A. J.

    Total odd nitrogen, NO(y), may be defined as the sum of all active nitrogen species that interchange photochemically with one another on a time scale of the order of weeks or less. As noted, NO + NO2 reactions dominate the processes controlling the ozone balance in the contemporary stratosphere. The observational data from non-satellite platforms are reviewed. The growth in available satellite data in the past four years is considered. Some of the most important scientific issues are discussed, taking into account new results from atmospheric models (mainly 2-D). The model results are compared with the observational data.

  2. Elevated Nitrogen Deposition from Alberta Oil Sands Development Stimulates Phosphatase Activity in Dominant Sphagnum Moss Species

    Science.gov (United States)

    Kashi, N. N.; Wieder, R.; Vile, M. A.

    2013-12-01

    Emissions of NOx associated with Alberta oil sands (AOS) development are leading to locally elevated atmospheric N deposition, in a region where background N deposition has been historically quite low (acid phosphatase activities in living plant capitulum of Sphagnum angustifolium, Sphagnum fuscum, and Sphagnum magellanicum were quantified in June and July using 4-methyumbelliferylphosphate and fluorescence detection of the enzymatically released methylumbelliferone (MUF). Phosphatase activities did not differ with N treatment for S. angustifolium in the bog (p=0.3409) or the poor fen (p=0.0629), or for S. fuscum in the bog (p=0.1950), averaging 35.0 × 0.7, 61.6 × 1.2, and 41.6 × 0.9 μmol MUF/g DWT/hr, respectively. For S. fuscum in the poor fen, phosphatase activities differed between N treatments (p=0.0275), ranging 40.6 × 1.1 μmol MUF/g DWT/hr in the control plots to 73.7 × 2.0 μmol MUF/g DWT/hr in the 5 kg/ha/yr N treatment plots; increasing N deposition did not result in a gradual change in enzyme activity. On the other hand, S. magellanicum phosphatase activities differed between N treatments (p=0.0189) and showed a pattern of generally increasing activity with increasing N deposition (37.4 × 0.5 μmol MUF/g DWT/hr in control plots; 97.9 × 4.5 μmol MUF/g DWT/hr in the 25 kg/ha/yr N treatment plots). The differing phosphatase responses between these dominant Sphagnum species suggest unique differences in nutrient balance and/or microbial activity. Combining the three moss species and weighting by their abundances within each plot (percent cover), phosphatase activities differed between N treatments in the bog (p=0.0388) and the poor fen (p=0.0005), with the latter exhibiting a clear increase in enzyme activity with increasing N deposition, and a doubling of phosphatase activity between the control plots and the 25 kg/kg/yr N deposition treatment. Although the three moss species responded differently, at the plot scale, increasing N deposition

  3. Reactive Oxygen and Nitrogen Species in Defense/Stress Responses Activated by Chitosan in Sycamore Cultured Cells

    Directory of Open Access Journals (Sweden)

    Massimo Malerba

    2015-01-01

    Full Text Available Chitosan (CHT is a non-toxic and inexpensive compound obtained by deacetylation of chitin, the main component of the exoskeleton of arthropods as well as of the cell walls of many fungi. In agriculture CHT is used to control numerous diseases on various horticultural commodities but, although different mechanisms have been proposed, the exact mode of action of CHT is still unknown. In sycamore (Acer pseudoplatanus L. cultured cells, CHT induces a set of defense/stress responses that includes production of H2O2 and nitric oxide (NO. We investigated the possible signaling role of these reactive molecules in some CHT-induced responses by means of inhibitors of production and/or scavengers. The results show that both reactive nitrogen and oxygen species are not only a mere symptom of stress conditions but are involved in the responses induced by CHT in sycamore cells. In particular, NO appears to be involved in a cell death form induced by CHT that shows apoptotic features like DNA fragmentation, increase in caspase-3-like activity and release of cytochrome c from the mitochondrion. On the contrary, reactive oxygen species (ROS appear involved in a cell death form induced by CHT that does not show these apoptotic features but presents increase in lipid peroxidation.

  4. Reactive oxygen and nitrogen species in defense/stress responses activated by chitosan in sycamore cultured cells.

    Science.gov (United States)

    Malerba, Massimo; Cerana, Raffaella

    2015-01-29

    Chitosan (CHT) is a non-toxic and inexpensive compound obtained by deacetylation of chitin, the main component of the exoskeleton of arthropods as well as of the cell walls of many fungi. In agriculture CHT is used to control numerous diseases on various horticultural commodities but, although different mechanisms have been proposed, the exact mode of action of CHT is still unknown. In sycamore (Acer pseudoplatanus L.) cultured cells, CHT induces a set of defense/stress responses that includes production of H2O2 and nitric oxide (NO). We investigated the possible signaling role of these reactive molecules in some CHT-induced responses by means of inhibitors of production and/or scavengers. The results show that both reactive nitrogen and oxygen species are not only a mere symptom of stress conditions but are involved in the responses induced by CHT in sycamore cells. In particular, NO appears to be involved in a cell death form induced by CHT that shows apoptotic features like DNA fragmentation, increase in caspase-3-like activity and release of cytochrome c from the mitochondrion. On the contrary, reactive oxygen species (ROS) appear involved in a cell death form induced by CHT that does not show these apoptotic features but presents increase in lipid peroxidation.

  5. Characteristics of an Electron Cyclotron Resonance Plasma Source for the Production of Active Nitrogen Species in III-V Nitride Epitaxy

    Science.gov (United States)

    Meyyappan, Meyya; Arnold, James O. (Technical Monitor)

    1997-01-01

    A simple analysis is provided to determine the characteristics of an electron cyclotron resonance (ECR) plasma source for the generation of active nitrogen species in the molecular beam epitaxy of III-V nitrides. The effects of reactor geometry, pressure, power, and flow rate on the dissociation efficiency and ion flux are presented. Pulsing the input power is proposed to reduce the ion flux.

  6. Control of nitrogen species in helicon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, R F [Department of Physics, Auburn University, Auburn, Alabama, 36849-5311 (United States); Scime, E E [Department of Physics, West Virginia University, Morgantown, West Virginia, 26506-6315 (United States)

    2005-05-01

    There are several possible reactions for both growth and decomposition of GaN layers in stable plasma conditions. A greater understanding of the plasma processes involved in the creation of the different N{sub 2} species is required before many growth related problems can be resolved. A plasma source capable of selecting different active nitrogen species could be used to study the different reactions related to the growth process. In this paper, we present a spectroscopic study of a helicon plasma source. Five different nitrogen species in the plasma are monitored, namely: N II (atomic ion), N I (atomic neutral), N{sub 2}{sup +}(molecular ion) and two different excited states of the N{sub 2} molecule as a function of the filling pressure. We show that by simply changing one plasma parameter (operating pressure), the plasma undergoes a transformation from an essentially atomic nature at low pressure to a dominantly molecular nature at higher pressure. The line intensity variations as a function of electron temperature are consistent with expectations based on the published formation rates for each species.

  7. Reactive Nitrogen Species and Nitric Oxide

    OpenAIRE

    D. Procházková; Wilhelmová, N. (Naděžda); Pavlík, M. (Milan)

    2015-01-01

    Free radical nitric oxide (NO) is a biological messenger with diverse functions in plant physiology, including in stress physiology. Together with NO, related molecules called reactive nitrogen species (RNS), e.g. peroxynitrite or S-nitrosothiols, are associated with plant metabolism under both physiological and stress conditions. These molecules are able to react with wide spectrum of biomolecules, and they may act as a transporters and reservoirs for NO in a broad range of plant cell signal...

  8. Antioxidant Activity/Capacity Measurement. 3. Reactive Oxygen and Nitrogen Species (ROS/RNS) Scavenging Assays, Oxidative Stress Biomarkers, and Chromatographic/Chemometric Assays.

    Science.gov (United States)

    Apak, Reşat; Özyürek, Mustafa; Güçlü, Kubilay; Çapanoğlu, Esra

    2016-02-10

    There are many studies in which the antioxidant potential of different foods have been analyzed. However, there are still conflicting results and lack of information as a result of unstandardized assay techniques and differences between the principles of the methods applied. The measurement of antioxidant activity, especially in the case of mixtures, multifunctional or complex multiphase systems, cannot be evaluated satisfactorily using a simple antioxidant test due to the many variables influencing the results. In the literature, there are many antioxidant assays that are used to measure the total antioxidant activity/capacity of food materials. In this review, reactive oxygen and nitrogen species (ROS/RNS) scavenging assays are evaluated with respect to their mechanism, advantages, disadvantages, and potential use in food systems. On the other hand, in vivo antioxidant activity (AOA) assays including oxidative stress biomarkers and cellular-based assays are covered within the scope of this review. Finally, chromatographic and chemometric assays are reviewed, focusing on their benefits especially with respect to their time saving, cost-effective, and sensitive nature.

  9. Structure of Dihydrochalcones and Related Derivatives and Their Scavenging and Antioxidant Activity against Oxygen and Nitrogen Radical Species

    Directory of Open Access Journals (Sweden)

    Alexandre L. A. Bentes

    2011-02-01

    Full Text Available Quantum mechanical calculations at B3LYP/6-31G** level of theory were employed to obtain energy (E, ionization potential (IP, bond dissociation enthalpy (O-H BDE and stabilization energies (DEiso in order to infer the scavenging activity of dihydrochalcones (DHC and structurally related compounds. Spin density calculations were also performed for the proposed antioxidant activity mechanism of 2,4,6-trihydroxyacetophenone (2,4,6-THA. The unpaired electron formed by the hydrogen abstraction from the phenolic hydroxyl group of 2,4,6-THA is localized on the phenolic oxygen at 2, 6, and 4 positions, the C3 and C6 carbon atoms at ortho positions, and the C5 carbon atom at para position. The lowest phenolic oxygen contribution corresponded to the  highest scavenging activity value. It was found that antioxidant activity depends on the presence of a hydroxyl at the C2 and C4 positions and that there is a correlation between IP and O-H BDE and peroxynitrite scavenging activity and lipid peroxidation. These results identified the pharmacophore group for DHC.

  10. Xylem sap nitrogen compounds of some Crotalaria species

    Directory of Open Access Journals (Sweden)

    Vitória Angela Pierre

    1999-01-01

    Full Text Available Thirteen species of Crotalaria were analysed for nitrogen compounds in the xylem root bleeding sap. Amino acids were the main form of organic nitrogen found, but only traces of ureides were present. Of the four species analysed for amino acid composition, asparagine was found to be the major amino acid, accounting for over 68% of the nitrogen transported. No striking deviations from this general pattern was found between species, between vegetative and floral stages of development, or between nodulated and non-nodulated plants. It was concluded that the Crotalaria species studied here have an asparagine-based nitrogen metabolism, consistent with many other non-ureide-producing legume species.

  11. Anti-apoptotic mechanism of Bacoside rich extract against reactive nitrogen species induced activation of iNOS/Bax/caspase 3 mediated apoptosis in L132 cell line.

    Science.gov (United States)

    Anand, T; Pandareesh, M D; Bhat, Pratiksha V; Venkataramana, M

    2014-10-01

    Nitric oxide is a highly reactive free radical gas that reacts with a wide range of bio-molecules to produce reactive nitrogen species and exerts nitrative stress. Bacopa monniera is a traditional folk and ayurvedic medicine known to alleviate a variety of disorders. Aim of the present study is to evaluate the protective propensity of Bacopa monniera extract (BME) through its oxido-nitrosative and anti-apoptotic mechanism to attenuate sodium nitroprusside (SNP)-induced apoptosis in a human embryonic lung epithelial cell line (L132). Our results elucidate that pre-treatment of L132 cells with BME ameliorates the mitochondrial and plasma membrane damage induced by SNP as evidenced by MTT and LDH leakage assays. BME pre-treatment inhibited NO generation by down-regulating inducible nitric oxide synthase expression. BME exhibited potent antioxidant activity by up-regulating the antioxidant enzymes. SNP-induced damage to cellular, nuclear and mitochondrial integrity was also restored by BME, which was confirmed by ROS estimation, comet assay and mitochondrial membrane potential assays respectively. BME pre-treatment efficiently attenuated the SNP-induced apoptotic biomarkers such as Bax, cytochrome-c and caspase-3, which orchestrate the proteolytic damage of the cell. By considering all these findings, we report that BME protects L132 cells against SNP-induced toxicity via its free radical scavenging and anti-apoptotic mechanism.

  12. Nitrogen losses from perennial grass species.

    NARCIS (Netherlands)

    Vazquez de Aldana, B.R.; Geerts, R.; Berendse, F.

    1996-01-01

    Nitrogen losses from plants may occur through a variety of pathways, but so far, most studies have only quantified losses of nutrients by above-ground litter production. We used 15 N pulse labelling to quantify total nitrogen losses from above- and below-ground plant parts. Using this method we were

  13. Woody encroachment by nitrogen-fixing species: impacts on nitrogen biogeochemistry expressed through nitrogen trace gases

    Science.gov (United States)

    Sparks, J. P.; West, J. B.; Boutton, T. W.

    2011-12-01

    Woody plant encroachment is a globally important vegetation change that continues to transform former grasslands or savannas into woodlands. This dramatic and geographically widespread phenomenon appears to be driven primarily by human land use changes, including reduced fire frequency and heavy livestock grazing. Observed effects of increased woody plant abundance in grasslands generally include alterations of above- and belowground productivity, changes in the chemistry of litter inputs, modifications to rooting depths and distributions, altered biogeochemical and hydrologic processes, and changes in microclimate and energy balance. These changes to fundamental ecosystem characteristics have strong, but relatively poorly understood, potential to modify biogeochemical processes that can themselves influence regional and global climate through biogeochemistry-climate feedbacks. In addition, in South Texas woody encroachment has occurred across a complex landscape differing in soil type and water retention. This work tests the hypothesis that woody encroachment, in addition to increasing total nitrogen stocks in the system, has increased nitrogen losses due to increased rates of nitrogen soil gas efflux. Under dry soil conditions and in contrast to this hypothesis, reactive nitrogen soil efflux (NO + NOy + NH3) was 21.53 ± 3.4 ng N m-2 s-1 in intact grasslands compared to 6.23 ± 1.6 ng N m-2 s-1 in woodlands on the same soil type. The non-reactive nitrogen gas, nitrous oxide, was similar in magnitude between the grassland and encroached sites (~ 7 ng N m-2 s-1). Under moist soil conditions, the magnitude of flux increased and order of magnitude, but did not change the relative ranking. Measurements of soil respiration rate and microbial biomass suggest higher microbial activity in the encroached environment and potentially higher rates of immobilization by plants and microbes. Landscape position had a large overall effect on soil nitrogen trace gas efflux with

  14. Analysis of nitrogen species in titanium oxynitride ALD films

    Science.gov (United States)

    Sowińska, Małgorzata; Brizzi, Simone; Das, Chittaranjan; Kärkkänen, Irina; Schneidewind, Jessica; Naumann, Franziska; Gargouri, Hassan; Henkel, Karsten; Schmeißer, Dieter

    2016-09-01

    Titanium oxynitride films are prepared by plasma enhanced atomic layer deposition method using two different precursors and nitrogen sources. Synchrotron radiation-based X-ray photoelectron spectroscopy and X-ray absorption spectroscopy are used to characterize the nitrogen species incorporated within these films depending on the deposition parameters. It is found that nitrogen atoms in these films are differently bonded. In particular, it can be distinguished between Tisbnd ON and Tisbnd N bonding configurations and molecular nitrogen species caused by precursor fragments.

  15. Nitrogen deposition threatens species richness of grasslands across Europe

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, C.J. [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Gowing, D.J.G. [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Dupre, C.; Diekmann, M. [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Dorland, E. [Section of Landscape Ecology, Department of Geobiology, Utrecht University, P.O. Box 80084, 3508 TB Utrecht (Netherlands); Gaudnik, C.; Alard, D.; Corcket, E. [University of Bordeaux 1. UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Bleeker, A. [Department of Air Quality and Climate Change, Energy Research Centre of the Netherlands, P.O. Box 1, 1755 ZG Petten (Netherlands); Bobbink, R. [B-WARE Research Centre, Radboud University, P.O. Box 9010, 6525 ED Nijmegen (Netherlands); Fowler, D. [NERC Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB (United Kingdom); Mountford, J.O. [NERC Centre for Ecology and Hydrology, MacLean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Vandvik, V. [Department of Biology, University of Bergen, Box 7800, N-5020 Bergen (Norway); Aarrestad, P.A. [Norwegian Institute for Nature Research, NO-7485 Trondheim (Norway); Muller, S. [Laboratoire des Interactions Ecotoxicologie, Biodiversite et Ecosystemes LIEBE, UMR CNRS 7146, U.F.R. Sci. F.A., Campus Bridoux, Universite Paul Verlaine, Avenue du General Delestraint, F-57070 Metz (France); Dise, N.B. [Department of Environmental and Geographical Science, Manchester Metropolitan University, Manchester M1 5GD (United Kingdom)

    2010-09-15

    Evidence from an international survey in the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is reducing plant species richness in acid grasslands. Across the deposition gradient in this region (2-44 kg N ha{sup -1} yr{sup -1}) species richness showed a curvilinear response, with greatest reductions in species richness when deposition increased from low levels. This has important implications for conservation policies, suggesting that to protect the most sensitive grasslands resources should be focussed where deposition is currently low. Soil pH is also an important driver of species richness indicating that the acidifying effect of nitrogen deposition may be contributing to species richness reductions. The results of this survey suggest that the impacts of nitrogen deposition can be observed over a large geographical range. Atmospheric nitrogen deposition is reducing biodiversity in grasslands across Europe.

  16. Nitrogen deposition threatens species richness of grasslands across Europe

    International Nuclear Information System (INIS)

    Evidence from an international survey in the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is reducing plant species richness in acid grasslands. Across the deposition gradient in this region (2-44 kg N ha-1 yr-1) species richness showed a curvilinear response, with greatest reductions in species richness when deposition increased from low levels. This has important implications for conservation policies, suggesting that to protect the most sensitive grasslands resources should be focussed where deposition is currently low. Soil pH is also an important driver of species richness indicating that the acidifying effect of nitrogen deposition may be contributing to species richness reductions. The results of this survey suggest that the impacts of nitrogen deposition can be observed over a large geographical range. Atmospheric nitrogen deposition is reducing biodiversity in grasslands across Europe.

  17. Emissions of gaseous nitrogen species from manure management

    DEFF Research Database (Denmark)

    Dämmgen, Ulrich; Hutchings, Nick

    2008-01-01

    A procedure for the assessment of emissions of nitrogen (N) species (ammonia, nitrous oxide, nitric oxide, di-nitrogen) from the manure management system is developed, which treats N pools and flows including emissions strictly according to conservation of mass criteria. As all relevant flows in...

  18. Constrained preferences in nitrogen uptake across plant species and environments.

    Science.gov (United States)

    Wang, Lixin; Macko, Stephen A

    2011-03-01

    Knowledge of determining factors for nitrogen uptake preferences and how they are modified in changing environments are critical to understand ecosystem nitrogen cycling and to predict plant responses to future environmental changes. Two ¹⁵N tracer experiments utilizing a unique differential labelled nitrogen source were employed in both African savannas and greenhouse settings. The results demonstrated that nitrogen uptake preferences were constrained by the climatic conditions. As mainly indicated by root δ¹⁵N signatures at 1:1 ammonium/nitrate ratio, in the drier environments, plants preferred nitrate and in the wetter environments they preferred ammonium. Nitrogen uptake preferences were different across different ecosystems (e.g. from drier to wetter environments) even for the same species. More significantly, our experiments showed that the plant progeny continued to exhibit the same nitrogen preference as the parent plants in the field, even when removed from their native environment and the nitrogen source was changed dramatically. The climatic constraint of nitrogen uptake preference is likely influenced by ammonium/nitrate ratios in the native habitats of the plants. The constancy in nitrogen preference has important implications in predicting the success of plant communities in their response to climate change, to seed bank use and to reforestation efforts. PMID:21118424

  19. The effect of plant species on soil nitrogen mineralization

    NARCIS (Netherlands)

    Krift, van der A.J.; Berendse, F.

    2001-01-01

    1. To ascertain the influence of different plant species on nitrogen (N) cycling, we performed a long-term garden experiment with six grasses and five dicots with different potential growth rates, that are adapted to habitats with different nutrient supplies. We measured in situ N mineralization and

  20. Nitrogen transfer between herbivores and their forage species

    NARCIS (Netherlands)

    Sjogersten, Sofie; Kuijper, Dries P. J.; van der Wal, Rene; Loonen, Maarten J. J. E.; Huiskes, Ad H. L.; Woodin, Sarah J.

    2010-01-01

    Herbivores may increase the productivity of forage plants; however, this depends on the return of nutrients from faeces to the forage plants. The aim of this study was to test if nitrogen (N) from faeces is available to forage plants and whether the return of nutrients differs between plant species

  1. Characterization of nitrogen species incorporated into graphite using low energy nitrogen ion sputtering.

    Science.gov (United States)

    Kiuchi, Hisao; Kondo, Takahiro; Sakurai, Masataka; Guo, Donghui; Nakamura, Junji; Niwa, Hideharu; Miyawaki, Jun; Kawai, Maki; Oshima, Masaharu; Harada, Yoshihisa

    2016-01-01

    The electronic structures of nitrogen species incorporated into highly oriented pyrolytic graphite (HOPG), prepared by low energy (200 eV) nitrogen ion sputtering and subsequent annealing at 1000 K, were investigated by X-ray photoelectron spectroscopy (XPS), angle-dependent X-ray absorption spectroscopy (XAS), and Raman spectroscopy. An additional peak was observed at higher binding energy of 401.9 eV than 400.9 eV for graphitic1 N (graphitic N in the basal plane) in N 1s XPS, where graphitic2 N (graphitic N in the zigzag edge and/or vacancy sites) has been theoretically expected to appear. N 1s XPS showed that graphitic1 N and graphitic2 N were preferably incorporated under low nitrogen content doping conditions (8 × 10(13) ions cm(-2)), while pyridinic N and graphitic1 N were dominantly observed under high nitrogen content doping conditions. In addition, angle-dependent N 1s XAS showed that the graphitic N and pyridinic N atoms were incorporated into the basal plane of HOPG and thus were highly oriented. Furthermore, Raman spectroscopy revealed that low energy sputtering resulted in almost no fraction of the disturbed graphite surface layers under the lowest nitrogen doping condition. The suitable nitrogen doping condition was discovered for realizing the well-controlled nitrogen doped HOPG. The electrochemical properties for the oxygen reduction reaction of these samples in acidic solution were examined and discussed.

  2. Liquid Nitrogen (-196°C effect under pollen of some cultured or ornamental species

    Directory of Open Access Journals (Sweden)

    Sabina GLIGOR

    2006-05-01

    Full Text Available The criopreservation involve the stock of the vegetal material at low temperatures (-196°C in liquid nitrogen, in thermal conditions in which the division of cells and metabolic processes slow down, thus that the samplings may be conserved for long periods without suffering any genetic modifications. This stock technique is applied till present only on 80 vegetal species, keeping their seeds and vitrocultures preponderantly; researches were made regarding the maintenance of pollen in liquid nitrogen.The mature pollen, able to resist a higher degree of desiccation, may be conserved at low temperatures, without criopreservation. It was made researches on criopreservation of rise, maize, wheat, roses, sun flower and soy pollen. Our study purpose was to follow the impact of liquid nitrogen (-196°C about on viability of some cultured and ornamental species. The designed time of criopreservation it was 30 minutes and 7 days, using the TTC (tripheniltetrazole chloride method which allows testing the viability of vegetal material based on dehydrogenase activity.It was observed at Petunia hybrida species, that the pollen viability was low - in relevance with the witness represented from the pollen which was not resigned to the nitrogen liquid treatment - between percentage limits of 3.5-8%, in the case when the vegetal material was submersed 30 minutes in liquid nitrogen and 7.5-14.5% 7 days at (-196°C. The submersing of Nicotiana alata var. grandiflora species at 7 days, determined a low viability with 11.53%. The following two studied species Cucurbita and Hosta were proved to be the most resistant at submersing and maintenance in liquid nitrogen. The most affected pollen was Campsis radicans species. At Datura stramonium species was observed 2.59% a low viability of pollen, after 30 minutes of liquid nitrogen treatment, was 19.56%, after 7 days of submersing, the most pollen granules losing completely their viability.

  3. Effect of plant species on nitrogen recovery in aquaponics.

    Science.gov (United States)

    Hu, Zhen; Lee, Jae Woo; Chandran, Kartik; Kim, Sungpyo; Brotto, Ariane Coelho; Khanal, Samir Kumar

    2015-01-01

    Nitrogen transformations in aquaponics with different edible plant species, i.e., tomato (Lycopersicon esculentum) and pak choi (Brassica campestris L. subsp. chinensis) were systematically examined and compared. Results showed that nitrogen utilization efficiencies (NUE) of tomato- and pak choi-based aquaponic systems were 41.3% and 34.4%, respectively. The abundance of nitrifying bacteria in tomato-based aquaponics was 4.2-folds higher than that in pak choi-based aquaponics, primarily due to its higher root surface area. In addition, tomato-based aquaponics had better water quality than that of pak choi-based aquaponics. About 1.5-1.9% of nitrogen input were emitted to atmosphere as nitrous oxide (N2O) in tomato- and pak choi-based aquaponic systems, respectively, suggesting that aquaponics is a potential anthropogenic source of N2O emission. Overall, this is the first intensive study that examined the role plant species played in aquaponics, which could provide new strategy in designing and operating an aquaponic system.

  4. Effect of plant species on nitrogen recovery in aquaponics.

    Science.gov (United States)

    Hu, Zhen; Lee, Jae Woo; Chandran, Kartik; Kim, Sungpyo; Brotto, Ariane Coelho; Khanal, Samir Kumar

    2015-01-01

    Nitrogen transformations in aquaponics with different edible plant species, i.e., tomato (Lycopersicon esculentum) and pak choi (Brassica campestris L. subsp. chinensis) were systematically examined and compared. Results showed that nitrogen utilization efficiencies (NUE) of tomato- and pak choi-based aquaponic systems were 41.3% and 34.4%, respectively. The abundance of nitrifying bacteria in tomato-based aquaponics was 4.2-folds higher than that in pak choi-based aquaponics, primarily due to its higher root surface area. In addition, tomato-based aquaponics had better water quality than that of pak choi-based aquaponics. About 1.5-1.9% of nitrogen input were emitted to atmosphere as nitrous oxide (N2O) in tomato- and pak choi-based aquaponic systems, respectively, suggesting that aquaponics is a potential anthropogenic source of N2O emission. Overall, this is the first intensive study that examined the role plant species played in aquaponics, which could provide new strategy in designing and operating an aquaponic system. PMID:25650140

  5. Post-translational modifications mediated by reactive nitrogen species

    Science.gov (United States)

    del Río, Luis A; Barroso, Juan B

    2008-01-01

    In animal cells, nitric oxide and NO-derived molecules have been shown to mediate post-translational modifications such as S-nitrosylation and protein tyrosine nitration which are associated with cell signalling and pathological processes, respectively. In plant cells, knowledge of the function of these post-translational modifications under physiological and stress conditions is still very rudimentary. In this addendum, we briefly examine how reactive nitrogen species (RNS) can exert important effects on proteins that could mediate signalling processes in plants. PMID:19841652

  6. Global response patterns of terrestrial plant species to nitrogen addition.

    Science.gov (United States)

    Xia, Jianyang; Wan, Shiqiang

    2008-07-01

    Better understanding of the responses of terrestrial plant species under global nitrogen (N) enrichment is critical for projection of changes in structure, functioning, and service of terrestrial ecosystems. Here, a meta-analysis of data from 304 studies was carried out to reveal the general response patterns of terrestrial plant species to the addition of N. Across 456 terrestrial plant species included in the analysis, biomass and N concentration were increased by 53.6 and 28.5%, respectively, under N enrichment. However, the N responses were dependent upon plant functional types, with significantly greater biomass increases in herbaceous than in woody species. Stimulation of plant biomass by the addition of N was enhanced when other resources were improved. In addition, the N responses of terrestrial plants decreased with increasing latitude and increased with annual precipitation. Dependence of the N responses of terrestrial plants on biological realms, functional types, tissues, other resources, and climatic factors revealed in this study can help to explain changes in species composition, diversity, community structure and ecosystem functioning under global N enrichment. These findings are critical in improving model simulation and projection of terrestrial carbon sequestration and its feedbacks to global climate change, especially when progressive N limitation is taken into consideration. PMID:19086179

  7. Antioxidant activity of Cat's whiskers flavonoid on some reactive oxygen and nitrogen species generating inflammatory cells is mediated by scavenging of free radicals

    Institute of Scientific and Technical Information of China (English)

    Asis Bala; Biswakanth Kar; Indrajit Karmakar; R.B.Suresh Kumar; Pallab Kanti Haldar

    2012-01-01

    AIM:To find out the effect of Cat's whiskers (Cleome gynandra L.,Capparidaceae) flavonoid (CWF) for the scavenging of free radicals in some inflammatory cells.METHODS:Mouse erythrocyte's hemoglobin,peritoneal macrophage,and peripheral blood lymphocytes were oxidized either by some of toxic chemicals (nitrite,carbon tetrachloride) or by enzymatic stimulation (glucoseoxidase) to produce oxidative damage to cells.The protective effect of the CWF was examined,and the biochemical mechanism of action was also investigated in terms of the scavenging of free radicals.RESULTS:CWF (1-20 μg·mL-1) decreased glucoseoxidase and nitrite induce oxidative damage in a concentration dependent manner in an in vitro model and inhibited the lysis of RBC [(28.64 ±13.03)% and (70.31 ± 1.80)%] when mice were treated with CWF (25 and 50 mg·kg-1).To assess the antioxidant potential of CWF in the lymphocytes and macrophages in living animals,the effect of CWF was measured on the elevated level of superoxide anions production in the cells.CWF scavenged the superoxide anion (O2-) production and inhibited the O2-induced destruction of protein and lipid biomolecules.CONCLUSION:The study has established that the CWF mediates its antioxidant activity in some chronic inflammatory cells via its free radical scavenging activity.

  8. Science Letters: Nitrogen doping of activated carbon loading Fe2O3 and activity in carbon-nitric oxide reaction

    Institute of Scientific and Technical Information of China (English)

    WAN Xian-kai; ZOU Xue-quan; SHI Hui-xiang; WANG Da-hui

    2007-01-01

    Nitrogen doping of activated carbon loading Fe2O3 was performed by annealing in ammonia, and the activity of the modified carbon for NO reduction was studied in the presence of oxygen. Results show that Fe2O3 enhances the amount of surface oxygen complexes and facilitates nitrogen incorporation in the carbon, especially in the form of pyridinic nitrogen. The modified carbon shows excellent activity for NO reduction in the low temperature regime (<500 ℃) because of the cooperative effect of Fe2O3 and the surface nitrogen species.

  9. Ecological effects of atmospheric nitrogen deposition on soil enzyme activity

    Institute of Scientific and Technical Information of China (English)

    WANG Cong-yan; Lv Yan-na; LIU Xue-yan Liu; WANG Lei

    2013-01-01

    The continuing increase in human activities is causing global changes such as increased deposition of atmospheric nitrogen.There is considerable interest in understanding the effects of increasing atmospheric nitrogen deposition on soil enzyme activities,specifically in terms of global nitrogen cycling and its potential future contribution to global climate change.This paper summarizes the ecological effects of atmospheric nitrogen deposition on soil enzyme activities,including size-effects,stage-effects,site-effects,and the effects of different levels and forms of atmospheric nitrogen deposition.We discuss needs for further research on the relationship between atmospheric nitrogen deposition and soil enzymes.

  10. Nitrogen addition enhances drought sensitivity of young deciduous tree species

    Directory of Open Access Journals (Sweden)

    Christoph Dziedek

    2016-07-01

    Full Text Available Understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. Although there is evidence on the mode of nitrogen (N and drought (D effects on tree growth, our understanding of the interplay of these factors is still limited. Simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of N addition and D on the productivity of three tree species (Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii in relation to functional diverse species mixtures using data from a four-year field experiment in Northwest Germany. Here we show that species mixing can mitigate the negative effects of combined N fertilization and D events, but the community response is mainly driven by the combination of certain traits rather than the tree species richness of a community. For beech, we found that negative effects of D on growth rates were amplified by N fertilization (i.e. combined treatment effects were non-additive, while for oak and fir, the simultaneous effects of N and D were additive. Beech and oak were identified as most sensitive to combined N+D effects with a strong size-dependency observed for beech, suggesting that the negative impact of N+D becomes stronger with time as beech grows larger. As a consequence, the net biodiversity effect declined at the community level, which can be mainly assigned to a distinct loss of complementarity in beech-oak mixtures. This pattern, however, was not evident in the other species-mixtures, indicating that neighborhood composition (i.e. trait combination, but not tree species richness mediated the relationship between tree diversity and treatment effects on tree growth. Our findings point to the importance of the qualitative role (‘trait portfolio’ that biodiversity play in determining resistance of diverse tree communities to environmental changes. As such, they

  11. Nitrogen Addition Enhances Drought Sensitivity of Young Deciduous Tree Species.

    Science.gov (United States)

    Dziedek, Christoph; Härdtle, Werner; von Oheimb, Goddert; Fichtner, Andreas

    2016-01-01

    Understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. Although there is evidence on the mode of nitrogen (N) and drought (D) effects on tree growth, our understanding of the interplay of these factors is still limited. Simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of N addition and D on the productivity of three tree species (Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii) in relation to functional diverse species mixtures using data from a 4-year field experiment in Northwest Germany. Here we show that species mixing can mitigate the negative effects of combined N fertilization and D events, but the community response is mainly driven by the combination of certain traits rather than the tree species richness of a community. For beech, we found that negative effects of D on growth rates were amplified by N fertilization (i.e., combined treatment effects were non-additive), while for oak and fir, the simultaneous effects of N and D were additive. Beech and oak were identified as most sensitive to combined N+D effects with a strong size-dependency observed for beech, suggesting that the negative impact of N+D becomes stronger with time as beech grows larger. As a consequence, the net biodiversity effect declined at the community level, which can be mainly assigned to a distinct loss of complementarity in beech-oak mixtures. This pattern, however, was not evident in the other species-mixtures, indicating that neighborhood composition (i.e., trait combination), but not tree species richness mediated the relationship between tree diversity and treatment effects on tree growth. Our findings point to the importance of the qualitative role ('trait portfolio') that biodiversity play in determining resistance of diverse tree communities to environmental changes. As such, they provide further

  12. Reactions of inorganic nitrogen species in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Dell`Orco, P.C. [Texas Univ., Austin, TX (United States)

    1994-12-31

    Redox reactions of nitrate salts with NH3 and methanol were studied in near-critical and supercritical water at 350 to 530 C and constant pressure of 302 bar. Sodium nitrate decomposition reactions were investigated at similar conditions. Reactions were conducted in isothermal tubular reactor under plug flow. For kinetic modeling, nitrate and nitrite reactants were lumped into an NO{sub x}{sup -} reactant; kinetic expressions were developed for MNO{sub 3}/NH{sub 4}X and sodium nitrate decomposition reactions. The proposed elementary reaction mechanism for MNO{sub 3}/NH{sub 4}X reaction indicated that NO{sub 2} was the primary oxidizing species and that N{sub 2}/N{sub 2}O selectivities could be determined by the form of MNO{sub 3} used. This suggest a nitrogen control strategy for use in SCWO (supercritical water oxidation) processes; nitrate or NH3 could be used to remove the other, at reaction conditions far less severe than required by other methods. Reactions of nitrate with methanol indicated that nitrate was a better oxidant than oxygen in supercritical water. Nitrogen reaction products included NH3 and nitrite, while inorganic carbon was the major carbon reaction product. Analysis of excess experiments indicated that the reaction at 475 C was first order in methanol concentration and second order in NO{sub x}{sup -} concentration. In order to determine phase regimes for these reactions, solubility of sodium nitrate was determined for some 1:1 nitrate electrolytes. Solubilities were measured at 450 to 525 C, from 248 to 302 bar. A semi-empirical solvation model was shown to adequately describe the experimental sodium nitrate solubilities. Solubilities of Li, Na, and K nitrates revealed with cations with smaller ionic radii had greater solubilities with nitrate.

  13. Effect of nitrogen content on methane production by the marine algae gracilaria tikvahiae and ulva species

    Energy Technology Data Exchange (ETDEWEB)

    Habig, C.; De Busk, T.A.; Ryther, J.H.

    1984-01-01

    The rhodophyte Gracilaria tikvahiae and the chlorophyte Ulva species were grown under three different nitrogen enrichment regimes producing plants of each species with three different concentrations of tissue nitrogen. Each was then digested in batch-mode fermentation experiments. Both biogas and methane production were initially greater in Ulva but persisted longer in Gracilaria, resulting in similar performances for the two species over the entire time course of the experiment. Low-nitrogen Gracilaria contained more volatile solids and produced more biogas and methane per unit dry weight than did higher nitrogen plants, but about the same gas production per unit volatile solids. However, low nitrogen Ulva consistently out-performed the high nitrogen plants in gas production per unit volatile solids, total volatile solids reduction, and bioconversion efficiency. These results, in contrast with those found in higher plants, probably reflect the low fiber, high soluble carbohydrate levels of nitrogen-deficient seaweeds in general and of Ulva in particular.

  14. DNA damage and reactive nitrogen species are barriers to Vibrio cholerae colonization of the infant mouse intestine.

    Directory of Open Access Journals (Sweden)

    Bryan W Davies

    2011-02-01

    Full Text Available Ingested Vibrio cholerae pass through the stomach and colonize the small intestines of its host. Here, we show that V. cholerae requires at least two types of DNA repair systems to efficiently compete for colonization of the infant mouse intestine. These results show that V. cholerae experiences increased DNA damage in the murine gastrointestinal tract. Agreeing with this, we show that passage through the murine gut increases the mutation frequency of V. cholerae compared to liquid culture passage. Our genetic analysis identifies known and novel defense enzymes required for detoxifying reactive nitrogen species (but not reactive oxygen species that are also required for V. cholerae to efficiently colonize the infant mouse intestine, pointing to reactive nitrogen species as the potential cause of DNA damage. We demonstrate that potential reactive nitrogen species deleterious for V. cholerae are not generated by host inducible nitric oxide synthase (iNOS activity and instead may be derived from acidified nitrite in the stomach. Agreeing with this hypothesis, we show that strains deficient in DNA repair or reactive nitrogen species defense that are defective in intestinal colonization have decreased growth or increased mutation frequency in acidified nitrite containing media. Moreover, we demonstrate that neutralizing stomach acid rescues the colonization defect of the DNA repair and reactive nitrogen species defense defective mutants suggesting a common defense pathway for these mutants.

  15. Nitrogen and protein contents in some aquatic plant species

    Directory of Open Access Journals (Sweden)

    Krystyna Bytniewska

    2015-05-01

    Full Text Available Nitrogen and protein contents in higher aquatic plants deriving from a natural habitat were determined. The following plants were examined: Spirodela polyrrhiza (L. Schleid., Elodea canadensis Rich., Riccia fluitans L. Total nitrogen and nitrogen of respective fractions were determined by the Kjeldahl method. Nitrogen compounds were fractionated according to Thimann et al. Protein was extracted after Fletcher and Osborne and fractionated after Osborne. It was found, that total protein content in the plants under examination constitutes 18 to 25%o of dry matter. Albumins and glutelins are the most abundant protein fractions.

  16. In vitro scavenging capacity of annatto seed extracts against reactive oxygen and nitrogen species.

    Science.gov (United States)

    Chisté, Renan Campos; Mercadante, Adriana Zerlotti; Gomes, Ana; Fernandes, Eduarda; Lima, José Luís Fontes da Costa; Bragagnolo, Neura

    2011-07-15

    Bixa orellana L. (annatto), from Bixaceae family, is a native plant of tropical America, which accumulates several carotenoids (including bixin and norbixin), terpenoids, tocotrienols and flavonoids with potential antioxidant activity. In the present study, the in vitro scavenging capacity of annatto seed extracts against reactive oxygen species (ROS) and reactive nitrogen species (RNS) was evaluated and compared to the bixin standard. Annatto extracts were obtained using solvents with different polarities and their phenolic compounds and bixin levels were determined by high performance liquid chromatography coupled to diode array detector. All annatto extracts were able to scavenge all the reactive species tested at the low μg/mL range, with the exception of superoxide radical. The ethanol:ethyl acetate and ethyl acetate extracts of annatto seeds, which presented the highest levels of hypolaetin and bixin, respectively, were the extracts with the highest antioxidant capacity, although bixin standard presented the lowest IC(50) values. PMID:23140681

  17. Nitrogen in insects: implications for trophic complexity and species diversification.

    Science.gov (United States)

    Fagan, William F; Siemann, Evan; Mitter, Charles; Denno, Robert F; Huberty, Andrea F; Woods, H Arthur; Elser, James J

    2002-12-01

    Disparities in nutrient content (nitrogen and phosphorus) between herbivores and their plant resources have lately proven to have major consequences for herbivore success, consumer-driven nutrient cycling, and the fate of primary production in ecosystems. Here we extend these findings by examining patterns of nutrient content between animals at higher trophic levels, specifically between insect herbivores and predators. Using a recently compiled database on insect nutrient content, we found that predators exhibit on average 15% greater nitrogen content than herbivores. This difference persists after accounting for variation from phylogeny and allometry. Among herbivorous insects, we also found evidence that recently derived lineages (e.g., herbivorous Diptera and Lepidoptera) have, on a relative basis, 15%-25% less body nitrogen than more ancient herbivore lineages (e.g., herbivorous Orthoptera and Hemiptera). We elaborate several testable hypotheses for the origin of differences in nitrogen content between trophic levels and among phylogenetic lineages. For example, interspecific variation in insect nitrogen content may be directly traceable to differences in dietary nitrogen (including dilution by gut contents), selected for directly in response to the differential scarcity of dietary nitrogen, or an indirect consequence of adaptation to different feeding habits. From some functional perspectives, the magnitude rather than the source of the interspecific differences in nitrogen content may be most critical. We conclude by discussing the implications of the observed patterns for both the trophic complexity of food webs and the evolutionary radiation of herbivorous insects. PMID:18707465

  18. Spatial pattern of nitrogen deposition flux over Czech forests: a novel approach accounting for unmeasured nitrogen species

    Science.gov (United States)

    Hůnová, Iva; Stoklasová, Petra; Kurfürst, Pavel; Vlček, Ondřej; Schovánková, Jana; Stráník, Vojtěch

    2015-04-01

    atmospheric nitrogen deposition flux over the Czech forests collating all available data and model results. The aim of the presented study is to provide an improved, more reliable and more realistic estimate of spatial pattern of nitrogen deposition flux over one country. This has so far been based standardly on measurements of ambient N/NOx concentrations as dry deposition proxy, and N/NH4+ and N/NO3- as wet deposition proxy. For estimate of unmeasured species contributing to dry deposition, we used an Eulerian photochemical dispersion model CAMx, the Comprehensive Air Quality Model with extensions (ESSS, 2011), coupled with a high resolution regional numeric weather prediction model Aladin (Vlček, Corbet, 2011). Contribution of fog was estimated using a geostatistical data driven model. Final maps accounting for unmeasured species clearly indicate, that so far used approach results in substantial underestimation of nitrogen deposition flux. Substitution of unmeasured nitrogen species by modeled values seems to be a plausible way for approximation of total nitrogen deposition, and getting more realistic spatial pattern as input for further studies of likely nitrogen impacts on ecosystems. Acknowledgements: We would like to acknowledge the grants GA14-12262S - Effects of changing growth conditions on tree increment, stand production and vitality - danger or opportunity for the Central-European forestry?, and NAZV QI112A168 (ForSoil) of the Czech Ministry for Agriculture for support of this contribution. The input data used for the analysis were provided by the Czech Hydrometeorological Institute. References: Bobbink, R., Hicks, K., Galloway, J., Spranger, T., Alkemade, R. et al. (2010): Global Assessment of Nitrogen Deposition Effects on Terrestrial Plant Diversity: a Synthesis. Ecological Applications 20 (1), 30-59. Fowler D., O'Donoghue M., Muller J.B.A, et al. (2005): A chronology of nitrogen deposition in the UK between 1900 and 2000. Watter, Air & Soil Pollution: Focus

  19. Pyrolysis of superfine pulverized coal. Part 3. Mechanisms of nitrogen-containing species formation

    International Nuclear Information System (INIS)

    Highlights: • NH3 and NO formation mechanisms during superfine pulverized coal pyrolysis are investigated. • Influences of temperature, heating rate, particle size, atmosphere, and acid wash on the NH3 and NO formation are analyzed. • Transformations of nitrogen-containing structures in coal/char during pyrolysis are recognized through XPS observation. • Relationships among nitrogen-containing gaseous species during pyrolysis are discussed. - Abstract: With more stringent regulations being implemented, elucidating the formation mechanisms of nitrogen-containing species during the initial pyrolysis step becomes important for developing new NOx control strategies. However, there is a lack of agreement on the origins of NOx precursors during coal pyrolysis, in spite of extensive investigations. Hence, it is important to achieve a more precise knowledge of the formation mechanisms of nitrogen-contain species during coal pyrolysis. In this paper, pyrolysis experiments of superfine pulverized coal were performed in a fixed bed at low heating rates. The influences of temperature, coal type, particle size and atmosphere on the NH3 and NO evolution were discussed. There is a central theme to develop knowledge of the relationship between particle sizes and evolving behaviors of nitrogen-containing species. Furthermore, the catalytic role of inherent minerals in coal was proved to be effective on the partitioning of nitrogen during coal pyrolysis. In addition, the conversion pathways of heteroaromatic nitrogen structures in coal/char during pyrolysis were recognized through the X-ray photoelectron spectroscopy (XPS) analysis. Large quantities of pyridinic and quanternary nitrogen functionalities were formed during the thermal degradation. Finally, the relationships among the nitrogen-containing gaseous species during coal pyrolysis were discussed. In brief, a comprehensive picture of the volatile-nitrogen partitioning during coal pyrolysis is obtained in this work

  20. Carbon and nitrogen in forest floor and mineral soil under six common European tree species

    DEFF Research Database (Denmark)

    Vesterdal, Lars; Schmidt, Inger K.; Callesen, Ingeborg;

    2007-01-01

    The knowledge of tree species effects on soil C and N pools is scarce, particularly for European deciduous tree species. We studied forest floor and mineral soil carbon and nitrogen under six common European tree species in a common garden design replicated at six sites in Denmark. Three decades...

  1. Challenges in quantifying biosphere-atmosphere exchange of nitrogen species

    DEFF Research Database (Denmark)

    Sutton, M.A.; Nemitz, E.; Erisman, J.W.;

    2007-01-01

    Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depende...

  2. Comparison of Nitrogen Depletion and Repletion on Lipid Production in Yeast and Fungal Species

    Directory of Open Access Journals (Sweden)

    Shihui Yang

    2016-08-01

    Full Text Available Although it is well known that low nitrogen stimulates lipid accumulation, especially for algae and some oleaginous yeast, few studies have been conducted in fungal species, especially on the impact of different nitrogen deficiency strategies. In this study, we use two promising consolidated bioprocessing (CBP candidates to examine the impact of two nitrogen deficiency strategies on lipid production, which are the extensively investigated oleaginous yeast Yarrowia lipolytica, and the commercial cellulase producer Trichoderma reesei. We first utilized bioinformatics approaches to reconstruct the fatty acid metabolic pathway and demonstrated the presence of a triacylglycerol (TAG biosynthesis pathway in Trichoderma reesei. We then examined the lipid production of Trichoderma reesei and Y. lipomyces in different media using two nitrogen deficiency strategies of nitrogen natural repletion and nitrogen depletion through centrifugation. Our results demonstrated that nitrogen depletion was better than nitrogen repletion with about 30% lipid increase for Trichoderma reesei and Y. lipomyces, and could be an option to improve lipid production in both oleaginous yeast and filamentous fungal species. The resulting distinctive lipid composition profiles indicated that the impacts of nitrogen depletion on yeast were different from those for fungal species. Under three types of C/N ratio conditions, C16 and C18 fatty acids were the predominant forms of lipids for both Trichoderma reesei and Y. lipolytica. While the overall fatty acid methyl ester (FAME profiles of Trichoderma reesei were similar, the overall FAME profiles of Y. lipolytica observed a shift. The fatty acid metabolic pathway reconstructed in this work supports previous reports of lipid production in T. reesei, and provides a pathway for future omics studies and metabolic engineering efforts. Further investigation to identify the genetic targets responsible for the effect of nitrogen depletion on

  3. Comparison of Nitrogen Depletion and Repletion on Lipid Production in Yeast and Fungal Species

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shihui; Wang, Wei; Wei, Hui; Van Wychen, Stefanie; Pienkos, Philip T.; Zhang, Min; Himmel, Michael E.

    2016-09-01

    Although it is well known that low nitrogen stimulates lipid accumulation, especially for algae and some oleaginous yeast, few studies have been conducted in fungal species, especially on the impact of different nitrogen deficiency strategies. In this study, we use two promising consolidated bioprocessing (CBP) candidates to examine the impact of two nitrogen deficiency strategies on lipid production, which are the extensively investigated oleaginous yeast Yarrowia lipolytica, and the commercial cellulase producer Trichoderma reesei. We first utilized bioinformatics approaches to reconstruct the fatty acid metabolic pathway and demonstrated the presence of a triacylglycerol (TAG) biosynthesis pathway in Trichoderma reesei. We then examined the lipid production of Trichoderma reesei and Y. lipomyces in different media using two nitrogen deficiency strategies of nitrogen natural repletion and nitrogen depletion through centrifugation. Our results demonstrated that nitrogen depletion was better than nitrogen repletion with about 30% lipid increase for Trichoderma reesei and Y. lipomyces, and could be an option to improve lipid production in both oleaginous yeast and filamentous fungal species. The resulting distinctive lipid composition profiles indicated that the impacts of nitrogen depletion on yeast were different from those for fungal species. Under three types of C/N ratio conditions, C16 and C18 fatty acids were the predominant forms of lipids for both Trichoderma reesei and Y. lipolytica. While the overall fatty acid methyl ester (FAME) profiles of Trichoderma reesei were similar, the overall FAME profiles of Y. lipolytica observed a shift. The fatty acid metabolic pathway reconstructed in this work supports previous reports of lipid production in T. reesei, and provides a pathway for future omics studies and metabolic engineering efforts. Further investigation to identify the genetic targets responsible for the effect of nitrogen depletion on lipid production

  4. Challenges in quantifying biosphere-atmosphere exchange of nitrogen species

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, M.A. [Centre for Ecology and Hydrology (CEH), Edinburgh Research Station, Bush Estate, Penicuik, EH26 0QB (United Kingdom)], E-mail: ms@ceh.ac.uk; Nemitz, E. [Centre for Ecology and Hydrology (CEH), Edinburgh Research Station, Bush Estate, Penicuik, EH26 0QB (United Kingdom); Erisman, J.W. [ECN, Clean Fossil Fuels, PO Box 1, 1755 ZG Petten (Netherlands); Beier, C. [Riso National Laboratory, PO Box 49, DK-4000 Roskilde (Denmark); Bahl, K. Butterbach [Institute of Meteorology and Climate Research, Atmos. Environ. Research (IMK-IFU), Research Centre Karlsruhe GmbH, Kreuzeckbahnstr. 19, 82467 Garmisch-Partenkirchen (Germany); Cellier, P. [INRA Unite Mixte de Recherche, 78850 Thiverval-Grignon (France); Vries, W. de [Alterra, Green World Research, PO Box 47, 6700 AA Wageningen (Netherlands); Cotrufo, F. [Dip. Scienze Ambientali, Seconda Universita degli Studi di Napoli, via Vivaldi 43, 81100 Caserta (Italy); Skiba, U.; Di Marco, C.; Jones, S. [Centre for Ecology and Hydrology (CEH), Edinburgh Research Station, Bush Estate, Penicuik, EH26 0QB (United Kingdom); Laville, P.; Soussana, J.F.; Loubet, B. [INRA Unite Mixte de Recherche, 78850 Thiverval-Grignon (France); Twigg, M.; Famulari, D. [Centre for Ecology and Hydrology (CEH), Edinburgh Research Station, Bush Estate, Penicuik, EH26 0QB (United Kingdom); Whitehead, J.; Gallagher, M.W. [School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Williamson Building, Oxford Road, Manchester, M13 9PL (United Kingdom); Neftel, A.; Flechard, C.R. [Agroscope FAL Reckenholz, Federal Research Station for Agroecology and Agriculture, PO Box, CH 8046 Zurich (Switzerland)] (and others)

    2007-11-15

    Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N{sub 2} fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N{sub 2}O, NO and bi-directional NH{sub 3} exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols. - Current N research is separated by form; the challenge is to link N components, scales and issues.

  5. Preparation of nitrogen-doped titania and its photocatalytic activity

    Institute of Scientific and Technical Information of China (English)

    QIN Haoli; GU Guobang; LIU Song

    2007-01-01

    Yellowish nitrogen-doped titania was produced through sol-gel method in mild condition, with the elemental nitrogen derived from aqua ammonia. The titania catalysts were characterized using XRD, BET, TEM, XPS, and UV-Vis diffuse reflectance spectrophotometer, and their photocatalytic activities were evaluated under UV and visible light, respectively. The XRD results showed that all titania catalysts were anatase. More significantly, the crystallite size of nitrogen-doped titania increased with an increase in N/Ti proportion, and the doping of nitrogen could extend the absorption shoulder into the visible-light region, thus it possessed a higher visible-light activity illustrated by decolorization of methyl orange (65.3%) under the irradiation of visible light, whereas pure titania showed little of such kind of visible light activity.The UV-light activity of nitrogen-doped titania catalysts was worse than that of pure titania and Degussa P25. In the range of N/Ti proportion of 4-10 mol%, the activity of nitrogen-doped titania weakened appreciably in the visible-light region as the N/Ti proportion increased, whereas a reverse relationship existed under the irradiation of UV light.

  6. Nitrotyrosine-modified SERCA2: a cellular sensor of reactive nitrogen species

    Energy Technology Data Exchange (ETDEWEB)

    Bigelow, Diana J.

    2009-01-19

    The SERCA2 isoform of the sarco/endoplasmic reticulum Ca2+-ATPase is sensitive to cellular conditions of inflammation and oxidative stress as evidenced by the common appearance of 3-nitrotyrosine modified forms of SERCA2 in aging and disease in both striated and smooth muscle of humans and several rodent models. Structural-functional studies of nitrated SERCA2 in aging heart and skeletal muscle demonstrate stoichiometric nitration of vicinal tyrosines, Tyr-294 and Tyr-295, on the lumenal side of the membrane-spanning helix, M4 that correlates with partial inhibition of its Ca2+-ATPase activity suggesting a possible regulatory function in down-regulating mitochondrial energy production and the associated generation of reactive oxygen/nitrogen species. This review discusses recent work regarding the nitrative and redox sensitivity of SERCA2 in muscle with respect to general cellular mechanisms of turnover and repair of modified proteins.

  7. The emerging immunological role of post-translational modifications by reactive nitrogen species in cancer microenvironment.

    Science.gov (United States)

    De Sanctis, Francesco; Sandri, Sara; Ferrarini, Giovanna; Pagliarello, Irene; Sartoris, Silvia; Ugel, Stefano; Marigo, Ilaria; Molon, Barbara; Bronte, Vincenzo

    2014-01-01

    Under many inflammatory contexts, such as tumor progression, systemic and peripheral immune response is tailored by reactive nitrogen species (RNS)-dependent post-translational modifications, suggesting a biological function for these chemical alterations. RNS modify both soluble factors and receptors essential to induce and maintain a tumor-specific immune response, creating a "chemical barrier" that impairs effector T cell infiltration and functionality in tumor microenvironment and supports the escape phase of cancer. RNS generation during tumor growth mainly depends on nitric oxide production by both tumor cells and tumor-infiltrating myeloid cells that constitutively activate essential metabolic pathways of l-arginine catabolism. This review provides an overview of the potential immunological and biological role of RNS-induced modifications and addresses new approaches targeting RNS either in search of novel biomarkers or to improve anti-cancer treatment.

  8. Coupling ecosystems exposure to nitrogen and species sensitivity to hypoxia: modelling marine eutrophication in LCIA

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias; Koski, Marja; Hauschild, Michael Zwicky

    ecosystems and promote planktonic growth that may lead to marine eutrophication impacts. Excessive algal biomass and dissolved oxygen (DO) depletion typify the ecosystem response to the nutrient input. The present novel method couples a mechanistic model of coastal biological processes that determines......Characterisation modelling in Life Cycle Impact Assessment (LCIA) quantifies impacts of anthropogenic emissions by applying substance-specific impact potentials, or Characterisation Factors (CF), to the amount of substances emitted. Nitrogen (N) emissions from human activities enrich coastal marine......·kgN-1]) represents the potential impact on benthic and demersal marine species caused by N inputs. Preliminary results range from 2 (PAF)·m3·kgN-1 (Central Arctic Ocean) to 94 (PAF)·m3·kgN-1 (Baltic Sea). Comparative contributions per country or watersheds can also be obtained. Further adding...

  9. The correlation between nitrogen species in coke and NOx formation during regeneration☆

    Institute of Scientific and Technical Information of China (English)

    Teng Li; Chaohe Yang; Xiaobo Chen⁎; Libo Yao; Wei Liang; Xuemei Ding

    2016-01-01

    Nitrogen oxides (NOx) emission during the regeneration of coked fluid catalytic cracking (FCC) catalysts is an en-vironmental issue. In order to identify the correlations between nitrogen species in coke and different nitrogen-containing products in tail gas, three coked catalysts with multilayer structural coke molecules were prepared in a fixed bed with model compounds (o-xylene and quinoline) at first. A series of characterization methods were used to analyze coke, including elemental analysis, FT-IR, XPS, and TG–MS. XPS characterization indicates all coked catalysts present two types of nitrogen species and the type with a higher binding energy is related with the inner part nitrogen atoms interacting with acid sites. Due to the stronger adsorption ability on acid sites for basic nitrogen compounds, the multilayer structural coke has unbalanced distribution of carbon and ni-trogen atoms between the inner part and the outer edge, which strongly affects gas product formation. At the early stage of regeneration, oxidation starts from the outer edge and the product NO can be reduced to N2 in high CO concentration. At the later stage, the inner part rich in nitrogen begins to be exposed to O2. At this period, the formation of CO decreases due to lack of carbon atoms, which is not beneficial to the reduction of NO. There-fore, nitrogen species in the inner part of multilayer structural coke contributes more to NOX formation. Based on the multilayer structure model of coke molecule and its oxidation behavior, a possible strategy to control NOX emission was discussed merely from concept.

  10. [Distribution and bioavailability of nitrogen and phosphorus species in the urban dusts from Hefei City].

    Science.gov (United States)

    Li, Ru-Zhong; Zhou, Ai-Jia; Tong, Fang; Li, Feng; Qian, Jia-Zhong

    2012-04-01

    To find out the distribution and bioavailability of nitrogen (N) and phosphorus (P) species in the urban dusts of Hefei City, 52 samples were collected from impervious areas with six different urban land-use types. The contents of ammonia nitrogen (NH4(+) -N), nitrate nitrogen (NO3(-) -N), exchangeable P (Ex-P), Al-bound P (Al-P), Fe-bound P (Fe-P), occluded P (Oc-P), Ca-bound P (Ca-P), detrital apatite P (De-P), organic P (Or-P) as well as total nitrogen (TN) and total phosphorus (TP) were measured by sequential extraction methods. The studies on spatial distribution, correlation and bioavailability of nitrogen and phosphorus species were made according to the analyzed data. The results show that the TN is composed mainly of organic nitrogen (Or-N) while the TP consists chiefly of inorganic phosphorus (IP) in the urban dusts of Hefei City, and the spatial variability of nitrogen and phosphorus species contents are greatly affected by the mode of urban land-use type. In addition, there are significant correlations among partial nitrogen and phosphorus forms in dusts. Corresponding to different urban land-use types such as industrial area, commercial area, residential area, educational area, traffic area and public landscapes and city squares, the average ratios of bioavailable nitrogen content (the sum of NH4(+) -N and NO3(-) -N) to TN are 8.87%, 9.60%, 6.68%, 9.37%, 8.20% and 8.17%, respectively, while the mean ratios of bioavailable phosphorus content (the sum of Ex-P, Al-P and Fe-P) to TP, are equal to 6.70%, 18.19%, 10.10%, 9.69%, 10.64% and 14.03%, respectively. PMID:22720560

  11. Attenuation of reactive nitrogen species by different flavonoids enriched fractions of Schima Wallichii

    Institute of Scientific and Technical Information of China (English)

    Sanchita Das; Asis Bala; Manas Bhowmik; Lakshmi Kanta Ghosh

    2012-01-01

    Objective: To investigate Schima wallichii (S. wallichii) Choisy (Ternstroemiaceae) which is a well known plant of Sikkim in the Himalayan region, India. Methods: Therefore three major flavonoid enriched fractions (FPet.Ether, FChloroform and FEthylacetate) were isolated by petroleum ether chloroform and ethyl acetate successively. The reactive nitrogen species scavenging activity of the flavonoid fractions was established using biochemical assay to measure scavenging of 2, 2 diphenyl picrylhydrazyl (DPPH), nitric oxide (NO) and peroxinitrite. Results: FEthylacetate showed maximum scavenging activity: their IC50 being (7.33 ± 3.32), (7.11 ± 2.21), and (6.67 ± 2.23)μg/mL in DPPH, NO, peroxinitrite radical respectively. Presence of (57.32 ± 2.31) and (163.4 ±2.22) μg of flavonoids and phenolic compound in 1 mg of extract is assumed to be responsible for free radical scavenging activity. Conclusion: Taken together S. wallichii has potent free radical scavenging property indicating its importance in food supplement as a rich source of active flavonoid and phenolic compounds in ethyl acetate fraction which is responsible for its free radical scavenging as well as antioxidant activity.

  12. Biochemical characterization of reactive nitrogen species by eosinophil peroxidase in tyrosine nitration

    Directory of Open Access Journals (Sweden)

    Hitomi,Yoshiaki

    2007-02-01

    Full Text Available It is well known that eosinophils are involved in tyrosine nitration. In this study, we evaluated tyrosine nitration by rat eosinophils isolated from peritoneal fl uid and constituent eosinophils in the stomach. Rat peritoneal eosinophils activated with 1 μM phorbol myristate acetate (PMA and 50 μM NO2 ン showed immunostaining for nitrotyrosine only in smaller cells, despite the fact that eosinophils are capable of producing superoxide (O2·ン. Free tyrosine nitrating capacity after incubation with PMA and NO2 ン was 4-fold higher in eosinophils than in neutrophils. Catalase and ク- and コ -tocopherol inhibited free tyrosine nitration by reactive nitrogen species from eosinophils but not that by peroxynitrite. Superoxide dismutase augmented free tyrosine nitration by activated eosinophils and peroxynitrite. The concentration of nitric oxide released from eosinophils was relatively low (0.32 μM/106 cells/h and did not contribute to the formation of nitrotyrosine. On the other hand, most constituent eosinophils constituent in the rat stomach stimulated by PMA and NO2 ン showed tyrosine nitration capacity. These results suggest that intact cells other than apoptotic-like eosinophils eluted in the intraperitoneal cavity could not generate reactive species responsible for nitration by a peroxidase-dependent mechanism. In contrast, normal eosinophils in the stomach were capable of nitration, suggesting that the characteristics of eosinophils in gastric mucosa are diff erent from those eluted in the peritoneal cavity.

  13. Activation of copper by nitrogen and argon beams

    Energy Technology Data Exchange (ETDEWEB)

    Chetvertkova, Vera [IAP, Goethe-University, Frankfurt am Main (Germany); GSI Darmstadt (Germany); Mustafin, Edil; Strasik, Ivan [GSI Darmstadt (Germany); Belousov, Anton [TU Darmstadt (Germany); Latysheva, Ludmila; Sobolevsky, Nikolai [INR RAS, Moscow (Russian Federation); Ratzinger, Ulrich [IAP, Goethe-University, Frankfurt am Main (Germany)

    2012-07-01

    Monte Carlo transport codes are widely used for various purposes in nuclear physics, radiation protection, medical applications, accelerator design etc. Code verification by experiments is needed to be sure that the codes give accurate results. New data on the activation of copper by a nitrogen beam of 500 MeV/u is presented and compared with FLUKA and SHIELD simulation results. The activation of copper by a nitrogen beam is compared to activation by an argon beam and respective simulations. This gives a chance to see the accuracy of the codes at different projectile masses. Correspondences and discrepancies of calculations and experiments are discussed.

  14. Measuring reactive oxygen and nitrogen species with fluorescent probes: challenges and limitations

    Science.gov (United States)

    Kalyanaraman, Balaraman; Darley-Usmar, Victor; Davies, Kelvin J.A.; Dennery, Phyllis A.; Forman, Henry Jay; Grisham, Matthew B.; Mann, Giovanni E.; Moore, Kevin; Roberts, L. Jackson; Ischiropoulos, Harry

    2013-01-01

    The purpose of this position paper is to present a critical analysis of the challenges and limitations of the most widely used fluorescent probes for detecting and measuring reactive oxygen and nitrogen species. Where feasible, we have made recommendations for the use of alternate probes and appropriate analytical techniques that measure the specific products formed from the reactions between fluorescent probes and reactive oxygen and nitrogen species. We have proposed guidelines that will help present and future researchers with regard to the optimal use of selected fluorescent probes and interpretation of results. PMID:22027063

  15. AMPK signaling in skeletal muscle during exercise: Role of reactive oxygen and nitrogen species.

    Science.gov (United States)

    Morales-Alamo, David; Calbet, Jose A L

    2016-09-01

    Reactive oxygen and nitrogen species (RONS) are generated during exercise depending on intensity, duration and training status. A greater amount of RONS is released during repeated high-intensity sprint exercise and when the exercise is performed in hypoxia. By activating adenosine monophosphate-activated kinase (AMPK), RONS play a critical role in the regulation of muscle metabolism but also in the adaptive responses to exercise training. RONS may activate AMPK by direct an indirect mechanisms. Directly, RONS may activate or deactivate AMPK by modifying RONS-sensitive residues of the AMPK-α subunit. Indirectly, RONS may activate AMPK by reducing mitochondrial ATP synthesis, leading to an increased AMP:ATP ratio and subsequent Thr(172)-AMPK phosphorylation by the two main AMPK kinases: LKB1 and CaMKKβ. In presence of RONS the rate of Thr(172)-AMPK dephosphorylation is reduced. RONS may activate LKB1 through Sestrin2 and SIRT1 (NAD(+)/NADH.H(+)-dependent deacetylase). RONS may also activate CaMKKβ by direct modification of RONS sensitive motifs and, indirectly, by activating the ryanodine receptor (Ryr) to release Ca(2+). Both too high (hypoxia) and too low (ingestion of antioxidants) RONS levels may lead to Ser(485)-AMPKα1/Ser(491)-AMPKα2 phosphorylation causing inhibition of Thr(172)-AMPKα phosphorylation. Exercise training increases muscle antioxidant capacity. When the same high-intensity training is applied to arm and leg muscles, arm muscles show signs of increased oxidative stress and reduced mitochondrial biogenesis, which may be explained by differences in RONS-sensing mechanisms and basal antioxidant capacities between arm and leg muscles. Efficient adaptation to exercise training requires optimal exposure to pulses of RONS. Inappropriate training stimulus may lead to excessive RONS formation, oxidative inactivation of AMPK and reduced adaptation or even maladaptation. Theoretically, exercise programs should be designed taking into account the

  16. Nitrogen and phosphorus additions negatively affect tree species diversity in tropical forest regrowth trajectories.

    Science.gov (United States)

    Siddique, Ilyas; Vieira, Ima Célia Guimarães; Schmidt, Susanne; Lamb, David; Carvalho, Cláudio José Reis; Figueiredo, Ricardo de Oliveira; Blomberg, Simon; Davidson, Eric A

    2010-07-01

    Nutrient enrichment is increasingly affecting many tropical ecosystems, but there is no information on how this affects tree biodiversity. To examine dynamics in vegetation structure and tree species biomass and diversity, we annually remeasured tree species before and for six years after repeated additions of nitrogen (N) and phosphorus (P) in permanent plots of abandoned pasture in Amazonia. Nitrogen and, to a lesser extent, phosphorus addition shifted growth among woody species. Nitrogen stimulated growth of two common pioneer tree species and one common tree species adaptable to both high- and low-light environments, while P stimulated growth only of the dominant pioneer tree Rollinia exsucca (Annonaceae). Overall, N or P addition reduced tree assemblage evenness and delayed tree species accrual over time, likely due to competitive monopolization of other resources by the few tree species responding to nutrient enrichment with enhanced establishment and/or growth rates. Absolute tree growth rates were elevated for two years after nutrient addition. However, nutrient-induced shifts in relative tree species growth and reduced assemblage evenness persisted for more than three years after nutrient addition, favoring two nutrient-responsive pioneers and one early-secondary tree species. Surprisingly, N + P effects on tree biomass and species diversity were consistently weaker than N-only and P-only effects, because grass biomass increased dramatically in response to N + P addition. The resulting intensified competition probably prevented an expected positive N + P synergy in the tree assemblage. Thus, N or P enrichment may favor unknown tree functional response types, reduce the diversity of coexisting species, and delay species accrual during structurally and functionally complex tropical rainforest secondary succession. PMID:20715634

  17. [Effects of different fertilizer species on carbon and nitrogen leaching in a reddish paddy soil].

    Science.gov (United States)

    Liu, Xi-Yu; Zou, Jing-Dong; Xu, Li-Li; Zhang, Xin-Yu; Yang, Feng-Ting; Dai, Xiao-Qin; Wang, Zhong-Qiang; Sun, Xiao-Min

    2014-08-01

    Enhanced fertilization could decrease nitrogen utilization rate and increase carbon and nitrogen leaching, leading to water pollution in agricultural ecosystem. A long-term field experiment had been established on a reddish paddy soil of Qianyanzhou Ecological Experimental Station (114 degrees 53'E, 26 degrees 48'N) in Jiangxi Province in 1998. Soil solution samples were collected by clay tube and vacuum pump. Four fertilizer species treatments were selected: control with no fertilizer (CK), straw return (ST), nitrogen, phosphorus and potassium mineral fertilizers (NPK) and pig manure (OM), aiming to evaluate the effects of different species of fertilizer on carbon and nitrogen leaching in a double rice cropping system. The results showed that: (1) ammonium nitrogen (NH4(+) -N) was the major type of N in soil leachate in reddish paddy soil. The application of NPK could significantly increase the ammonium nitrogen concentration (1.2 mg x L(-1) +/- 0.1 mg x L(-1)) compared with the CK, ST and OM treatments, and the application of OM could significantly increase the dissolved organic carbon (DOC) concentration (27.3 mg x L(-1) +/- 1.6 mg x L(-1)) in soil leachate. The carbon and nitrogen leaching were more notable in the vegetative growth stage than the reproductive growth stage of rice (P NPK and OM increased the NH4(+) -N, DOC, soil organic carbon (SOC) and total nitrogen (TN) contents. The NPK was best beneficial to improve TN contents and OM to improve SOC contents. (3) The DOC contents in soil leachate and SOC in paddy soil had a positive correlation (P < 0.01), while NH4(+) -N contents in soil leachate and TN contents in paddy soil had a positive correlation (P < 0.01). PMID:25338383

  18. [Effects of different fertilizer species on carbon and nitrogen leaching in a reddish paddy soil].

    Science.gov (United States)

    Liu, Xi-Yu; Zou, Jing-Dong; Xu, Li-Li; Zhang, Xin-Yu; Yang, Feng-Ting; Dai, Xiao-Qin; Wang, Zhong-Qiang; Sun, Xiao-Min

    2014-08-01

    Enhanced fertilization could decrease nitrogen utilization rate and increase carbon and nitrogen leaching, leading to water pollution in agricultural ecosystem. A long-term field experiment had been established on a reddish paddy soil of Qianyanzhou Ecological Experimental Station (114 degrees 53'E, 26 degrees 48'N) in Jiangxi Province in 1998. Soil solution samples were collected by clay tube and vacuum pump. Four fertilizer species treatments were selected: control with no fertilizer (CK), straw return (ST), nitrogen, phosphorus and potassium mineral fertilizers (NPK) and pig manure (OM), aiming to evaluate the effects of different species of fertilizer on carbon and nitrogen leaching in a double rice cropping system. The results showed that: (1) ammonium nitrogen (NH4(+) -N) was the major type of N in soil leachate in reddish paddy soil. The application of NPK could significantly increase the ammonium nitrogen concentration (1.2 mg x L(-1) +/- 0.1 mg x L(-1)) compared with the CK, ST and OM treatments, and the application of OM could significantly increase the dissolved organic carbon (DOC) concentration (27.3 mg x L(-1) +/- 1.6 mg x L(-1)) in soil leachate. The carbon and nitrogen leaching were more notable in the vegetative growth stage than the reproductive growth stage of rice (P soil organic carbon (SOC) and total nitrogen (TN) contents. The NPK was best beneficial to improve TN contents and OM to improve SOC contents. (3) The DOC contents in soil leachate and SOC in paddy soil had a positive correlation (P soil leachate and TN contents in paddy soil had a positive correlation (P < 0.01).

  19. Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland

    DEFF Research Database (Denmark)

    Pirhofer-Walzl, Karin; Høgh Jensen, Henning; Eriksen, Jørgen;

    2012-01-01

    Legumes play a crucial role in nitrogen supply to grass-legume mixtures for ruminant fodder. To quantify N transfer from legumes to neighbouring plants in multi-species grasslands we established a grass-legume-herb mixture on a loamy-sandy site in Denmark. White clover (Trifolium repens L.), red ...

  20. Mitochondrial Signaling in Plants Under Hypoxia: Use of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS)

    DEFF Research Database (Denmark)

    Hebelstrup, Kim; Møller, Ian Max

    2015-01-01

    Hypoxia commonly occurs in roots in water-saturated soil and in maturing and germinating seeds. We here review the role of the mitochondria in the cellular response to hypoxia with an emphasis on the turnover of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) and their potential...... signaling function. Under hypoxia, aerobic respiration in the mitochondria can be limited by the oxygen supply, the electron transport component are more reduced and superoxide and NO are produced in increasing amounts at Complexes III and IV initiating the formation of a range of other ROS and RNS. Unless...

  1. Reactive Nitrogen Species-Dependent Effects on Soybean Chloroplasts

    OpenAIRE

    Puntarulo, Susana; Jasid, Sebastián; Simontacchi, Marcela

    2007-01-01

    Nitric oxide (NO) generation by soybean (Glycine max, var ADM 4800) chloroplasts was studied by electron paramagnetic resonance (EPR) spin-trapping technique.1 Both nitrite and L-arginine (arg) are the required substrates for enzymatic activities considered as possible sources of NO in plants. Soybean chloroplasts showed a NO production of 3.2 ± 0.2 nmol min−1 mg−1 protein in the presence of 1 mM NaNO2. Chloroplasts incubated with 1 mM arg showed a NO production of 0.76 ± 0.04 nmol min−1 mg−1...

  2. XPS of nitrogen-containing functional groups on activated carbon

    NARCIS (Netherlands)

    Jansen, R.J.J.; Bekkum, van H.

    1995-01-01

    XPS is used to study the binding energy of the Cls, Nls and Ols photoelectrons of surface groups on several nitrogen-containing activated carbons. Specific binding energies are assigned to amide (399.9 eV). lactam and imidc (399.7 eV). pyridine (398.7 eV), pyrrole (400.7 eV), alkylamine. secondary a

  3. Predicting Nitrogen Fertilizer Recommendations for Corn using an Active Sensor

    Science.gov (United States)

    Active sensors, mounted on typical agricultural equipment, can be used to measure N (nitrogen) status in corn (Zea mays L.). This gives a producer the potential to improve N fertilizer recommendations that will reduce nitrate loss to the environment. This study examines the relationship between re...

  4. Science Letters:Effect of nitrogen doping on the reduction of nitric oxide with activated carbon in the presence of oxygen

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Nitrogen doping of activated carbon (AC) was performed by annealing both in ammonia and nitric oxide, and the activities of the modified carbons for NO reduction were studied in the presence of oxygen. Results show that nitrogen atoms were incorporated into the carbons, mostly in the form of pyridinic nitrogen or pyridonic nitrogen. The effect of nitrogen doping on the activities of the carbons can be ignored when oxygen is absent, but the doped carbons show desirable activities in the low temperature regime (≤500 ℃) when oxygen is present. The role of the surface nitrogen species is suggested to promote the formation of NO2 in the presence of oxygen, and NO2 can facilitate decomposition of the surface oxygen species in the low temperature regime.

  5. Texas Endangered Species Activity Book.

    Science.gov (United States)

    Jackson, Kathleen Marie; Campbell, Linda

    This publication is the result of the Texas Parks and Wildlife Division's (TPWD's) commitment to education and the fertile partnerships formed between TPWD biologists and educators. This activity book brings together the expertise and practical knowledge of a classroom teacher with the technical knowledge and skills of a TPWD biologist and artist.…

  6. QQS orphan gene regulates carbon and nitrogen partitioning across species via NF-YC interactions.

    Science.gov (United States)

    Li, Ling; Zheng, Wenguang; Zhu, Yanbing; Ye, Huaxun; Tang, Buyun; Arendsee, Zebulun W; Jones, Dallas; Li, Ruoran; Ortiz, Diego; Zhao, Xuefeng; Du, Chuanlong; Nettleton, Dan; Scott, M Paul; Salas-Fernandez, Maria G; Yin, Yanhai; Wurtele, Eve Syrkin

    2015-11-24

    The allocation of carbon and nitrogen resources to the synthesis of plant proteins, carbohydrates, and lipids is complex and under the control of many genes; much remains to be understood about this process. QQS (Qua-Quine Starch; At3g30720), an orphan gene unique to Arabidopsis thaliana, regulates metabolic processes affecting carbon and nitrogen partitioning among proteins and carbohydrates, modulating leaf and seed composition in Arabidopsis and soybean. Here the universality of QQS function in modulating carbon and nitrogen allocation is exemplified by a series of transgenic experiments. We show that ectopic expression of QQS increases soybean protein independent of the genetic background and original protein content of the cultivar. Furthermore, transgenic QQS expression increases the protein content of maize, a C4 species (a species that uses 4-carbon photosynthesis), and rice, a protein-poor agronomic crop, both highly divergent from Arabidopsis. We determine that QQS protein binds to the transcriptional regulator AtNF-YC4 (Arabidopsis nuclear factor Y, subunit C4). Overexpression of AtNF-YC4 in Arabidopsis mimics the QQS-overexpression phenotype, increasing protein and decreasing starch levels. NF-YC, a component of the NF-Y complex, is conserved across eukaryotes. The NF-YC4 homologs of soybean, rice, and maize also bind to QQS, which provides an explanation of how QQS can act in species where it does not occur endogenously. These findings are, to our knowledge, the first insight into the mechanism of action of QQS in modulating carbon and nitrogen allocation across species. They have major implications for the emergence and function of orphan genes, and identify a nontransgenic strategy for modulating protein levels in crop species, a trait of great agronomic significance.

  7. Effects of water and nitrogen addition on species turnover in temperate grasslands in northern China.

    Directory of Open Access Journals (Sweden)

    Zhuwen Xu

    Full Text Available Global nitrogen (N deposition and climate change have been identified as two of the most important causes of current plant diversity loss. However, temporal patterns of species turnover underlying diversity changes in response to changing precipitation regimes and atmospheric N deposition have received inadequate attention. We carried out a manipulation experiment in a steppe and an old-field in North China from 2005 to 2009, to test the hypothesis that water addition enhances plant species richness through increase in the rate of species gain and decrease in the rate of species loss, while N addition has opposite effects on species changes. Our results showed that water addition increased the rate of species gain in both the steppe and the old field but decreased the rates of species loss and turnover in the old field. In contrast, N addition increased the rates of species loss and turnover in the steppe but decreased the rate of species gain in the old field. The rate of species change was greater in the old field than in the steppe. Water interacted with N to affect species richness and species turnover, indicating that the impacts of N on semi-arid grasslands were largely mediated by water availability. The temporal stability of communities was negatively correlated with rates of species loss and turnover, suggesting that water addition might enhance, but N addition would reduce the compositional stability of grasslands. Experimental results support our initial hypothesis and demonstrate that water and N availabilities differed in the effects on rate of species change in the temperate grasslands, and these effects also depend on grassland types and/or land-use history. Species gain and loss together contribute to the dynamic change of species richness in semi-arid grasslands under future climate change.

  8. Soil carbon accumulation and nitrogen retention traits of four tree species grown in common gardens

    DEFF Research Database (Denmark)

    Gurmesa, Geshere Abdisa; Schmidt, Inger Kappel; Gundersen, Per;

    2013-01-01

    Tree species effects on soil carbon (C) accumulation are uncertain, especially with respect to the mineral soil C, and the consistency of such effects across soil types is not known. The interaction between C accumulation and nitrogen (N) retention among common tree species has also been little...... explored. Effects of four tree species on soil C and N stocks and soil water nitrate concentration below the root zone were evaluated in a common garden design replicated at eight sites in Denmark. The tree species were beech (Fagus sylvatica L.), oak (Quercus robur L.), larch (Larix leptolepis Kaempf......), and Norway spruce (Picea abies (L) Karst.). After four decades, there were significant differences in forest floor C stocks among all four species, and C stocks increased consistently in the order oak

  9. [Effects of elevated atmospheric CO2 and nitrogen application on cotton biomass, nitrogen utilization and soil urease activity].

    Science.gov (United States)

    Lyu, Ning; Yin, Fei-hu; Chen, Yun; Gao, Zhi-jian; Liu, Yu; Shi, Lei

    2015-11-01

    In this study, a semi-open-top artificial climate chamber was used to study the effect of CO2 enrichment (360 and 540 µmol · mol(-1)) and nitrogen addition (0, 150, 300 and 450 kg · hm(-2)) on cotton dry matter accumulation and distribution, nitrogen absorption and soil urease activity. The results showed that the dry matter accumulation of bud, stem, leaf and the whole plant increased significantly in the higher CO2 concentration treatment irrespective of nitrogen level. The dry matter of all the detected parts of plant with 300 kg · hm(-2) nitrogen addition was significantly higher than those with the other nitrogen levels irrespective of CO2 concentration, indicating reasonable nitrogen fertilization could significantly improve cotton dry matter accumulation. Elevated CO2 concentration had significant impact on the nitrogen absorption contents of cotton bud and stem. Compared to those under CO2 concentration of 360 µmol · mol(-1), the nitrogen contents of bud and stem both increased significantly under CO2 concentration of 540 µmol · mol(-1). The nitrogen content of cotton bud in the treatment of 300 kg · hm(-2) nitrogen was the highest among the four nitrogen fertilizer treatments. While the nitrogen contents of cotton stem in the treatments of 150 kg · hm(-2) and 300 kg · hm(-2) nitrogen levels were higher than those in the treatment of 0 kg · hm(-2) and 450 kg · hm(-2) nitrogen levels. The nitrogen content of cotton leaf was significantly influenced by the in- teraction of CO2 elevation and N addition as the nitrogen content of leaf increased in the treatments of 0, 150 and 300 kg · hm(-2) nitrogen levels under the CO2 concentration of 540 µmol · mol(-1). The nitrogen content in cotton root was significantly increased with the increase of nitrogen fertilizer level under elevated CO2 (540 µmol · mol(-1)) treatment. Overall, the cotton nitrogen absorption content under the elevated CO2 (540 µmol · mol(-1)) treatment was higher than that

  10. Emissions of gaseous nitrogen species from manure management: A new approach

    Energy Technology Data Exchange (ETDEWEB)

    Daemmgen, Ulrich [Federal Agricultural Research Centre, Institute of Agroecology, Bundesallee 50, 38116 Braunschweig (Germany)], E-mail: ulrich.daemmgen@fal.de; Hutchings, Nicholas J. [Danish Institute of Agricultural Sciences, Department of Agroecology, Tjele (Denmark)], E-mail: nick.hutchings@agrsci.dk

    2008-08-15

    A procedure for the assessment of emissions of nitrogen (N) species (ammonia, nitrous oxide, nitric oxide, di-nitrogen) from the manure management system is developed, which treats N pools and flows including emissions strictly according to conservation of mass criteria. As all relevant flows in the husbandry of mammals are depicted, the methodology is considered a Tier 3 approach in IPCC terminology or a detailed methodology in UN ECE terminology. The importance of accounting for all N species is illustrated by comparing emission estimates obtained using this approach with those obtained from the application the present detailed/Tier 2 methodology. - A cow is a cow. There is no distinction between an IPCC and a UN ECE cow{exclamation_point}.

  11. Targeting reactive nitrogen species: a promising therapeutic strategy for cerebral ischemia-reperfusion injury

    OpenAIRE

    Chen, Xing-miao; Chen, Han-sen; Xu, Ming-jing; Shen, Jian-gang

    2012-01-01

    Ischemic stroke accounts for nearly 80% of stroke cases. Recanalization with thrombolysis is a currently crucial therapeutic strategy for re-building blood supply, but the thrombolytic therapy often companies with cerebral ischemia-reperfusion injury, which are mediated by free radicals. As an important component of free radicals, reactive nitrogen species (RNS), including nitric oxide (NO) and peroxynitrite (ONOO(-)), play important roles in the process of cerebral ischemia-reperfusion injur...

  12. Microbial biomass and N mineralization in mixed plantations of broadleaves and nitrogen-fixing species

    OpenAIRE

    Pereira, Ermelinda; SANTOS, Sónia A.P.; Arrobas, Margarida; Claro, Ana Marília; Patrício, Maria do Sameiro

    2010-01-01

    The present study was conducted in a 10-year-old trial of mixed plantation located in the Northeast of Portugal. This study was developed in the three following treatments: pure of Robinia pseudoacacia; pure of Prunus avium and mixed of Prunus avium × Robinia pseudoacacia. To better understand the benefit of the consociation of an N-fixing species (Robinia pseudoacacia) with broadleaves quality timber production (Prunus avium), we compared the soil microbial biomass carbon and nitrogen, soil ...

  13. Measurement of Reactive Oxygen Species, Reactive Nitrogen Species, and Redox-Dependent Signaling in the Cardiovascular System: A Scientific Statement From the American Heart Association.

    Science.gov (United States)

    Griendling, Kathy K; Touyz, Rhian M; Zweier, Jay L; Dikalov, Sergey; Chilian, William; Chen, Yeong-Renn; Harrison, David G; Bhatnagar, Aruni

    2016-08-19

    Reactive oxygen species and reactive nitrogen species are biological molecules that play important roles in cardiovascular physiology and contribute to disease initiation, progression, and severity. Because of their ephemeral nature and rapid reactivity, these species are difficult to measure directly with high accuracy and precision. In this statement, we review current methods for measuring these species and the secondary products they generate and suggest approaches for measuring redox status, oxidative stress, and the production of individual reactive oxygen and nitrogen species. We discuss the strengths and limitations of different methods and the relative specificity and suitability of these methods for measuring the concentrations of reactive oxygen and reactive nitrogen species in cells, tissues, and biological fluids. We provide specific guidelines, through expert opinion, for choosing reliable and reproducible assays for different experimental and clinical situations. These guidelines are intended to help investigators and clinical researchers avoid experimental error and ensure high-quality measurements of these important biological species.

  14. Nitrogen

    Science.gov (United States)

    Kramer, D.A.

    2006-01-01

    In 2005, ammonia was produced by 15 companies at 26 plants in 16 states in the United States. Of the total ammonia production capacity, 55% was centered in Louisiana, Oklahoma and Texas because of their large reserves of natural gas. US producers operated at 66% of their rated capacity. In descending order, Koch Nitrogen, Terra Industries, CF Industries, Agrium and PCS Nitrogen accounted for 81% of the US ammonia production capacity.

  15. Effects of four nitrogen substrates on growth of several red tide species

    Institute of Scientific and Technical Information of China (English)

    颜天; 周名江; 钱培元

    2002-01-01

    --Eight common red tide species including the Dinoflagellates Ale randrium tamarense,Prorocentrum minimum, Prorocentrum mican, Diatoms Skeletonema costatum , Cerataulina pelagica, Leptocylindrus minimus, a Raphidophyte Heterosigma akashiwo and a Chrysophyte Ivohrysis galbana were chosen to study the effect of four nitrogen substrates ( NO3 - N, NH4 - N, Urea - N,Mixed - N) on the growth of these algae. After two transfers, the results showed that at N concentration of 550μrnol, NO3 N was the best nitrogen source among these four nitrogen substrates; Urea - N and Mixed- N were also good for the growth of most algae, but not as good as NO3 - N for some species; NH4 - N inhibited the growth of all these species except H. akashiwo. At concentrations of 280 and 50 μmnol experiments on the growth of I. galbana, P. minimum and L. minimus in NH4 - N and NO3 - N substrates were also performed. The results showed that the growth rates of I. galbana were not significantly different from each other in NO3 - N and NH4 - N substrates both concentrations of 280 and 50 μmol. In concentration of 280μmol NH4 - N substrate, the growth rates of P.minimum and L. minimus were slower than in same concentration of NO3 - N; At concentration of 50μrmol , the growth rate of P. minimum in NH4 - N was not significantly different from that in NO3 - N, while the growth rate of L. minimus was only about 30% of that in NO3 - N substrate.The results indicated that each alga had its own preference in N-substrate and concentration, therefore,different nitrogen substrates may play a role in red tide formation.

  16. Responses of Ammonia-Oxidising Bacterial Communities to Nitrogen, Lime, and Plant Species in Upland Grassland Soil

    Directory of Open Access Journals (Sweden)

    Deirdre C. Rooney

    2010-01-01

    Full Text Available Agricultural improvement of seminatural grasslands has been shown to result in changes to plant and microbial diversity, with consequences for ecosystem functioning. A microcosm approach was used to elucidate the effects of two key components of agricultural improvement (nitrogen addition and liming on ammonia-oxidising bacterial (AOB communities in an upland grassland soil. Plant species characteristic of unimproved and improved pastures (A. capillaris and L. perenne were planted in microcosms, and lime, nitrogen (NH4NO3, or lime plus nitrogen added. The AOB community was profiled using terminal restriction fragment length polymorphism (TRFLP of the amoA gene. AOB community structure was largely altered by NH4NO3 addition, rather than liming, although interactions between nitrogen addition and plant species were also evident. Results indicate that nitrogen addition drives shifts in the structure of key microbial communities in upland grassland soils, and that plant species may play a significant role in determining AOB community structure.

  17. Responses of Ammonia-Oxidising Bacterial Communities to Nitrogen, Lime, and Plant Species in Upland Grassland Soil

    International Nuclear Information System (INIS)

    Agricultural improvement of semi natural grasslands has been shown to result in changes to plant and microbial diversity, with consequences for ecosystem functioning. A microcosm approach was used to elucidate the effects of two key components of agricultural improvement (nitrogen addition and liming) on ammonia-oxidising bacterial (AOB) communities in an upland grassland soil. Plant species characteristic of unimproved and improved pastures (A. capillaries and L. perenne) were planted in microcosms, and lime, nitrogen (NH4NO3), or lime plus nitrogen added. The AOB community was profiled using terminal restriction fragment length polymorphism (TRFLP) of the amoA gene. AOB community structure was largely altered by NH4NO3 addition, rather than liming, although interactions between nitrogen addition and plant species were also evident. Results indicate that nitrogen addition drives shifts in the structure of key microbial communities in upland grassland soils, and that plant species may play a significant role in determining AOB community structure

  18. Shifts in species composition constrain restoration of overgrazed grassland using nitrogen fertilization in Inner Mongolian steppe, China.

    Directory of Open Access Journals (Sweden)

    Qing Chen

    Full Text Available Long-term livestock over-grazing causes nitrogen outputs to exceed inputs in Inner Mongolia, suggesting that low levels of nitrogen fertilization could help restore grasslands degraded by overgrazing. However, the effectiveness of such an approach depends on the response of production and species composition to the interactive drivers of nitrogen and water availability. We conducted a five-year experiment manipulating precipitation (NP: natural precipitation and SWP: simulated wet year precipitation and nitrogen (0, 25 and 50 kg N ha(-1 yr(-1 addition in Inner Mongolia. We hypothesized that nitrogen fertilization would increase forage production when water availability was relatively high. However, the extent to which nitrogen would co-limit production under average or below average rainfall in these grasslands was unknown.Aboveground net primary production (ANPP increased in response to nitrogen when precipitation was similar to or higher than the long-term average, but not when precipitation was below average. This shift in limitation was also reflected by water and nitrogen use efficiency. Belowground live biomass significantly increased with increasing water availability, but was not affected by nitrogen addition. Under natural precipitation (NP treatment, the inter-annual variation of ANPP was 3-fold greater than with stable water availability (CV(ANPP = 61±6% and 17±3% for NP and SWP treatment, respectively and nitrogen addition increased CV(ANPP even more (89±14%. This occurred in part because fertilizer nitrogen left in the soil in dry years remained available for uptake during wet years and because of high production by unpalatable annual species in wet years in the NP treatment. In summary, plant growth by residual fertilizer nitrogen could lead to sufficient yields to offset lack of additional production in dry years. However, the utility of fertilization for restoration may be constrained by shifts in species composition and

  19. Shifts in species composition constrain restoration of overgrazed grassland using nitrogen fertilization in Inner Mongolian steppe, China.

    Science.gov (United States)

    Chen, Qing; Hooper, David U; Lin, Shan

    2011-01-01

    Long-term livestock over-grazing causes nitrogen outputs to exceed inputs in Inner Mongolia, suggesting that low levels of nitrogen fertilization could help restore grasslands degraded by overgrazing. However, the effectiveness of such an approach depends on the response of production and species composition to the interactive drivers of nitrogen and water availability. We conducted a five-year experiment manipulating precipitation (NP: natural precipitation and SWP: simulated wet year precipitation) and nitrogen (0, 25 and 50 kg N ha(-1) yr(-1)) addition in Inner Mongolia. We hypothesized that nitrogen fertilization would increase forage production when water availability was relatively high. However, the extent to which nitrogen would co-limit production under average or below average rainfall in these grasslands was unknown.Aboveground net primary production (ANPP) increased in response to nitrogen when precipitation was similar to or higher than the long-term average, but not when precipitation was below average. This shift in limitation was also reflected by water and nitrogen use efficiency. Belowground live biomass significantly increased with increasing water availability, but was not affected by nitrogen addition. Under natural precipitation (NP treatment), the inter-annual variation of ANPP was 3-fold greater than with stable water availability (CV(ANPP) = 61±6% and 17±3% for NP and SWP treatment, respectively) and nitrogen addition increased CV(ANPP) even more (89±14%). This occurred in part because fertilizer nitrogen left in the soil in dry years remained available for uptake during wet years and because of high production by unpalatable annual species in wet years in the NP treatment. In summary, plant growth by residual fertilizer nitrogen could lead to sufficient yields to offset lack of additional production in dry years. However, the utility of fertilization for restoration may be constrained by shifts in species composition and the lack of

  20. Soil NH4+/NO3-nitrogen characteristics in primary forests and the adaptability of some coniferous species

    Institute of Scientific and Technical Information of China (English)

    CUI Xiaoyang; SONG Jinfeng

    2007-01-01

    the adaptation to NH4+-dominated systems (or limited ability to use NO3-) for the coniferous species include:i) distribution and activity of enzymes for catalyzing nitrogen reduction and assimilation,generally characterized by lower nitrate reductase (NR);ii) greater tolerance to NH4+ or rapid detoxification of ammonium nitrogen in the roots;iii) lower capacity of absorption to NO3-by roots that might be controlled by feedback regulations of certain N-transport compounds,such as glutamine;iv) relations and balance between nitrogen and other elements (such as Ca2+,Mg2+,and Zn2+ etc.).Some NH4+-preferred conifers might be more adapted (tolerant) to lower base cation conditions;v)NO3-nutrition,rather than NH4+,that may lead to the loss of considerable quantities of organic and inorganic carbon to the surrounding media and mycorrhizal symbiont and probably contribute to slower growth;and vi) the metabolic cost of reducing NO3-to NH4+ that may make shade-tolerant conifers favor the uptake of reduced nitrogen (NH4+).The adaptation of late successional conifers to NH4+-dominated habitats has profound ecological implications.First,it might be an important prerequisite for the climax forest communities dominated by these conifers to maintainlong-term stability.Second,primary coniferous or conifer-ous-broadleaved forests have been widely perturbed because of commercial exploitation,where the soil ammonium nitrogen pool tends to be largely transformed to nitrate after disturbance.In such a situation,the coniferous species that were dominant in undisturbed ecosystems may become poor competitors for nitrogen,and the site will be occupied by early successional (pioneer) plants better adapted to nitrate utilization.In other words,the implicit adaptation of many conifers dominant in undisturbed communities to ammonium nitrogen will cause difficulties in their regeneration on disturbed sites,which must be taken into account in the practical restoration of degraded temperate forest

  1. Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates in northwestern Turkey

    Directory of Open Access Journals (Sweden)

    Sariyildiz T

    2016-02-01

    Full Text Available Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates were investigated in the northwest of Turkey using 4 common tree species as black pine (Pinus nigra Arnold., Scots pine (Pinus sylvestris L., Oriental beech (Fagus orientalis Lipsky and Uludag fir (Abies nordmanniana ssp. bornmuelleriana. Three tree species (black pine, Scots pine and Oriental beech were used to investigate the differences in soil C and N among tree species. Old and young Uludag fir stands and adjacent grassland were used to study the differences in soil C and N with stand age and land-use change. Mineral soil samples were taken from 0-10 cm and 10-20 cm soil depths, and analyzed for pH, soil texture, bulk density, total soil carbon and total nitrogen. The total soil carbon and total nitrogen pools were then calculated by multiplying soil volume, soil bulk density, and the total soil carbon or total nitrogen content. Results showed significant differences in soil carbon and nitrogen contents, carbon/nitrogen ratios and stock rates among the three species, and between old and young fir stands and grassland. In general, when 0-20 cm soil depth was considered, mean soil carbon stock rate was the highest under black pine (79 Mg C ha-1 followed by Scots pine (73 Mg C ha-1 and beech (67 Mg C ha-1, whereas mean soil nitrogen stock rate was the highest under beech (9.57 Mg N ha-1 followed by Scots pine (5.77 Mg N ha-1 and black pine (4.20 Mg N ha-1. Young fir stands showed lower soil carbon stock, but higher soil nitrogen stock rates compared to old fir stands and grassland. Our results demonstrated that tree species, stand tree age and land-use change can have significant effects on soil carbon and nitrogen content and stocks rates. These findings can help to enhance forest management activities, such as selection of tree species for carbon sequestration in plantation systems, design of sustainable agroforestry systems, and improvement of

  2. Seabird nutrient subsidies benefit non-nitrogen fixing trees and alter species composition in South American coastal dry forests.

    Directory of Open Access Journals (Sweden)

    Gilles Havik

    Full Text Available Marine-derived nutrients can increase primary productivity and change species composition of terrestrial plant communities in coastal and riverine ecosystems. We hypothesized that sea nutrient subsidies have a positive effect on nitrogen assimilation and seedling survival of non-nitrogen fixing species, increasing the relative abundance of non-nitrogen fixing species close to seashore. Moreover, we proposed that herbivores can alter the effects of nutrient supplementation by preferentially feeding on high nutrient plants. We studied the effects of nutrient fertilization by seabird guano on tree recruitment and how these effects can be modulated by herbivorous lizards in the coastal dry forests of northwestern Peru. We combined field studies, experiments and stable isotope analysis to study the response of the two most common tree species in these forests, the nitrogen-fixing Prosopis pallida and the non-nitrogen-fixing Capparis scabrida. We did not find differences in herbivore pressure along the sea-inland gradient. We found that the non-nitrogen fixing C. scabrida assimilates marine-derived nitrogen and is more abundant than P. pallida closer to guano-rich soil. We conclude that the input of marine-derived nitrogen through guano deposited by seabirds feeding in the Pacific Ocean affects the two dominant tree species of the coastal dry forests of northern Peru in contrasting ways. The non-nitrogen fixing species, C. scabrida may benefit from sea nutrient subsidies by incorporating guano-derived nitrogen into its foliar tissues, whereas P. pallida, capable of atmospheric fixation, does not.

  3. Nitrogen enrichment weakens ecosystem stability through decreased species asynchrony and population stability in a temperate grassland.

    Science.gov (United States)

    Zhang, Yunhai; Loreau, Michel; Lü, Xiaotao; He, Nianpeng; Zhang, Guangming; Han, Xingguo

    2016-04-01

    Biodiversity generally promotes ecosystem stability. To assess whether the diversity-stability relationship observed under ambient nitrogen (N) conditions still holds under N enriched conditions, we designed a 6-year field experiment to test whether the magnitude and frequency of N enrichment affects ecosystem stability and its relationship with species diversity in a temperate grassland. Results of this experiment showed that the frequency of N addition had no effect on either the temporal stability of ecosystem and population or the relationship between diversity and stability. Nitrogen addition decreased ecosystem stability significantly through decreases in species asynchrony and population stability. Species richness was positively associated with ecosystem stability, but no significant relationship between diversity and the residuals of ecosystem stability was detected after controlling for the effects of the magnitude of N addition, suggesting collinearity between the effects of N addition and species richness on ecosystem stability, with the former prevailing over the latter. Both population stability and the residuals of population stability after controlling for the effects of the magnitude of N addition were positively associated with ecosystem stability, indicating that the stabilizing effects of component populations were still present after N enrichment. Our study supports the theory predicting that the effects of environmental factors on ecosystem functioning are stronger than those of biodiversity. Understanding such mechanisms is important and urgent to protect biodiversity in mediating ecosystem functioning and services in the face of global changes. PMID:26511538

  4. Differences in the growth response of three bryophyte species to nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Salemaa, Maija [Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa (Finland)], E-mail: maija.salemaa@metla.fi; Maekipaeae, Raisa [Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa (Finland)], E-mail: raisa.makipaa@metla.fi; Oksanen, Jari [University of Oulu, Department of Biology, P.O. Box 3000, FI-90014 Oulu (Finland)], E-mail: jarioksa@sun3.oulu.fi

    2008-03-15

    The effect of nitrogen on biomass production, shoot elongation and relative density of the mosses Pleurozium schreberi, Hylocomium splendens and Dicranum polysetum was studied in a chamber experiment. Monocultures were exposed to 10 N levels ranging from 0.02 to 7.35 g N m{sup -2} during a 90-day period. All the growth responses were unimodal, but the species showed differences in the shape parameters of the curves. Hylocomium and Pleurozium achieved optimum biomass production at a lower N level than Dicranum. Pleurozium had the highest biomass production per tissue N concentration. Tolerance to N was the widest in Dicranum, whereas Hylocomium had the narrowest tolerance. Dicranum retained N less efficiently from precipitation than the other two species, which explained its deviating response. All species translocated some N from parent to new shoots. The results emphasize that the individual responses of bryophytes to N should be known when species are used as bioindicators. - Boreal bryophytes display differences in their sensitivity to nitrogen.

  5. Bacterial Diversity and Community Structure in Two Bornean Nepenthes Species with Differences in Nitrogen Acquisition Strategies.

    Science.gov (United States)

    Sickel, Wiebke; Grafe, T Ulmar; Meuche, Ivonne; Steffan-Dewenter, Ingolf; Keller, Alexander

    2016-05-01

    Carnivorous plants of the genus Nepenthes have been studied for over a century, but surprisingly little is known about associations with microorganisms. The two species Nepenthes rafflesiana and Nepenthes hemsleyana differ in their pitcher-mediated nutrient sources, sequestering nitrogen from arthropod prey and arthropods as well as bat faeces, respectively. We expected bacterial communities living in the pitchers to resemble this diet difference. Samples were taken from different parts of the pitchers (leaf, peristome, inside, outside, digestive fluid) of both species. Bacterial communities were determined using culture-independent high-throughput amplicon sequencing. Bacterial richness and community structure were similar in leaves, peristomes, inside and outside walls of both plant species. Regarding digestive fluids, bacterial richness was higher in N. hemsleyana than in N. rafflesiana. Additionally, digestive fluid communities were highly variable in structure, with strain-specific differences in community composition between replicates. Acidophilic taxa were mostly of low abundance, except the genus Acidocella, which strikingly reached extremely high levels in two N. rafflesiana fluids. In N. hemsleyana fluid, some taxa classified as vertebrate gut symbionts as well as saprophytes were enriched compared to N. rafflesiana, with saprophytes constituting potential competitors for nutrients. The high variation in community structure might be caused by a number of biotic and abiotic factors. Nitrogen-fixing bacteria were present in both study species, which might provide essential nutrients to the plant at times of low prey capture and/or rare encounters with bats. PMID:26790863

  6. Seabird nutrient subsidies benefit non-nitrogen fixing trees and alter species composition in South American coastal dry forests

    NARCIS (Netherlands)

    Havik, G.; Catenazzi, A.; Holmgren, M.

    2014-01-01

    Marine-derived nutrients can increase primary productivity and change species composition of terrestrial plant communities in coastal and riverine ecosystems. We hypothesized that sea nutrient subsidies have a positive effect on nitrogen assimilation and seedling survival of non-nitrogen fixing spec

  7. Markers of protein oxidation by hydroxyl radical and reactive nitrogen species in tissues of aging rats.

    Science.gov (United States)

    Leeuwenburgh, C; Hansen, P; Shaish, A; Holloszy, J O; Heinecke, J W

    1998-02-01

    Many lines of evidence implicate oxidative damage in aging. Possible pathways include reactions that modify aromatic amino acid residues on proteins. o-Tyrosine is a stable marker for oxidation of protein-bound phenylalanine by hydroxyl radical, whereas 3-nitrotyrosine is a marker for oxidation of protein-bound tyrosine by reactive nitrogen species. To test the hypothesis that proteins damaged by hydroxyl radical and reactive nitrogen accumulate with aging, we used isotope dilution gas chromatography-mass spectrometry to measure levels of o-tyrosine and 3-nitrotyrosine in heart, skeletal muscle, and liver from young adult (9 mo) and old (24 mo) female Long-Evans/Wistar hybrid rats. We also measured these markers in young adult and old rats that received antioxidant supplements (alpha-tocopherol, beta-carotene, butylated hydroxytoluene, and ascorbic acid) from the age of 5 mo. We found that aging did not significantly increase levels of protein-bound o-tyrosine or 3-nitrotyrosine in any of the tissues. Antioxidant supplementation had no effect on the levels of protein-bound o-tyrosine and 3-nitrotyrosine in either young or old animals. These observations indicate that the o-tyrosine and 3-nitrotyrosine do not increase significantly in heart, skeletal muscle, and liver in old rats, suggesting that proteins damaged by hydroxyl radical and reactive nitrogen species do not accumulate in these tissues with advancing age. PMID:9486304

  8. Nitrogen removal from coal gasification wastewater by activated carbon technologies combined with short-cut nitrogen removal process.

    Science.gov (United States)

    Zhao, Qian; Han, Hongjun; Hou, Baolin; Zhuang, Haifeng; Jia, Shengyong; Fang, Fang

    2014-11-01

    A system combining granular activated carbon and powdered activated carbon technologies along with shortcut biological nitrogen removal (GAC-PACT-SBNR) was developed to enhance total nitrogen (TN) removal for anaerobically treated coal gasification wastewater with less need for external carbon resources. The TN removal efficiency in SBNR was significantly improved by introducing the effluent from the GAC process into SBNR during the anoxic stage, with removal percentage increasing from 43.8%-49.6% to 68.8%-75.8%. However, the TN removal rate decreased with the progressive deterioration of GAC adsorption. After adding activated sludge to the GAC compartment, the granular carbon had a longer service-life and the demand for external carbon resources became lower. Eventually, the TN removal rate in SBNR was almost constant at approx. 43.3%, as compared to approx. 20.0% before seeding with sludge. In addition, the production of some alkalinity during the denitrification resulted in a net savings in alkalinity requirements for the nitrification reaction and refractory chemical oxygen demand (COD) degradation by autotrophic bacteria in SBNR under oxic conditions. PACT showed excellent resilience to increasing organic loadings. The microbial community analysis revealed that the PACT had a greater variety of bacterial taxons and the dominant species associated with the three compartments were in good agreement with the removal of typical pollutants. The study demonstrated that pre-adsorption by the GAC-sludge process could be a technically and economically feasible method to enhance TN removal in coal gasification wastewater (CGW). PMID:25458677

  9. Spatial gradient in nitrogen deposition affects plant species frequency in acidic grasslands.

    Science.gov (United States)

    Pannek, A; Duprè, C; Gowing, D J G; Stevens, C J; Diekmann, M

    2015-01-01

    Anthropogenic eutrophication impacts ecosystems worldwide. Here, we use a vegetation dataset from semi-natural grasslands on acidic soils sampled along a gradient in north-western Europe to examine the response of species frequency to nitrogen (N) deposition, controlling for the effects of other environmental variables. A second dataset of acidic grasslands from Germany and the Netherlands containing plots from different time periods was analysed to examine whether the results of the spatial gradient approach coincided with temporal changes in the abundance of species. Out of 44 studied species, 16 were affected by N deposition, 12 of them negatively. Soil pH and phosphorus (P) influenced 24 and 14 species, respectively, predominantly positively. Fewer species were related to the soil contents of NO3(-) or NH4(+), with no significant differences between the number of positive and negative effects. Whereas the temporal change of species was unrelated to their responses to pH, species responding negatively to N deposition, soil P and NO3(-) showed a significant decline over time in both countries. Species that were negatively affected by high N deposition and/or high soil P also showed a negative temporal trend and could be characterised by short stature and slow growth. The results confirm the negative role of N deposition for many plant species in semi-natural acidic grasslands. The negative temporal trends of species sensitive to high N deposition and soil P values clearly show a need for maintaining low soil nutrient status and for restoring the formerly infertile conditions in nutrient-enriched grasslands. PMID:25407619

  10. Antifungal activity of five species of Polygala

    Directory of Open Access Journals (Sweden)

    Susana Johann

    2011-09-01

    Full Text Available Crude extracts and fractions of five species of Polygala - P. campestris, P. cyparissias, P. paniculata, P. pulchella and P. sabulosa - were investigated for their in vitro antifungal activity against opportunistic Candida species, Cryptococcus gattii and Sporothrix schenckii with bioautographic and microdilution assays. In the bioautographic assays, the major extracts were active against the fungi tested. In the minimal concentration inhibitory (MIC assay, the hexane extract of P. paniculata and EtOAc fraction of P. sabulosa showed the best antifungal activity, with MIC values of 60 and 30 µg/mL, respectively, against C. tropicalis, C. gattii and S. schenckii. The compounds isolated from P. sabulosa prenyloxycoumarin and 1,2,3,4,5,6-hexanehexol displayed antifungal activity against S. schenckii (with MICs of 125 µg/mL and 250 µg/mL, respectively and C. gattii (both with MICs of 250 µg/mL. Rutin and aurapten isolated from P. paniculata showed antifungal activity against C. gattii with MIC values of 60 and 250 µg/mL, respectively. In the antifungal screening, few of the isolated compounds showed good antifungal inhibition. The compound α-spinasterol showed broad activity against the species tested, while rutin had the best activity with the lowest MIC values for the microorganisms tested. These two compounds may be chemically modified by the introduction of a substitute group that would alter several physico-chemical properties of the molecule, such as hydrophobicity, electronic density and steric strain.

  11. Mineralization of nitrogen by protozoan activity in soil.

    NARCIS (Netherlands)

    Kuikman, P.J.

    1990-01-01

    In general, more than 95% of the nitrogen in soils is present in organic forms. This nitrogen is not directly available to plants unless microbial decomposition takes place with the release of mineral nitrogen. In modern agriculture, nitrogen is often applied to arable soils as a fertilizer to suppo

  12. Azospirillum fermentarium sp. nov., a nitrogen-fixing species isolated from a fermenter.

    Science.gov (United States)

    Lin, Shih-Yao; Liu, You-Cheng; Hameed, Asif; Hsu, Yi-Han; Lai, Wei-An; Shen, Fo-Ting; Young, Chiu-Chung

    2013-10-01

    An aerobic, Gram-stain-negative, spiral or rod-shaped, non-spore-forming, diazotrophic bacterium (strain CC-LY743(T)) was isolated from a fermentative tank in Taiwan. Strain CC-LY743(T) was able to grow at 20-37 °C and pH 6.0-8.0 and tolerated up to 3.0 % (w/v) NaCl. It was positive for nitrogen fixation, with activity of 10.6 nmol ethylene h(-1). 16S rRNA gene sequence analysis of strain CC-LY743(T) showed highest similarity to Azospirillum picis DSM 19922(T) (96.1 %), Azospirillum oryzae JCM 21588(T) (96.0 %) and Azospirillum rugosum DSM 19657(T) (96.0 %) and lower similarity (Azospirillum species. Highest nifH gene sequence similarities were obtained with Azospirillum brasilense BCRC 12270(T) (92.0 %), Azospirillum formosense BCRC 80273(T) (92.3 %) and A. rugosum DSM 19657(T) (91.8 %). It was positive in the rapid identification by a genus-specific primer set. The predominant quinone system was ubiquinone 10 (Q-10) and the DNA G+C content was 69.6±0.1 mol%. The major fatty acids found in strain CC-LY743(T) were n-C16 : 0, C19 : 0 cyclo ω8c, C14 : 0 3-OH/C16 : 1 iso I, C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c. Based on its phylogenetic, phenotypic and chemotaxonomic features, strain CC-LY743(T) is considered to represent a novel species within the genus Azospirillum for which the name Azospirillum fermentarium sp. nov. is proposed. The type strain is CC-LY743(T) ( = BCRC 80505(T) = JCM 18688(T) = LMG 27264(T)).

  13. Mineralization of nitrogen by protozoan activity in soil.

    OpenAIRE

    Kuikman, P.J.

    1990-01-01

    In general, more than 95% of the nitrogen in soils is present in organic forms. This nitrogen is not directly available to plants unless microbial decomposition takes place with the release of mineral nitrogen. In modern agriculture, nitrogen is often applied to arable soils as a fertilizer to support high levels of crop production. Nitrogen is one of the essential nutrients and is required by plants in substantial amounts (1.5-5% x g -1dry weight). Extensive application of fertilizer nitroge...

  14. Biochemical studies on certain biologically active nitrogenous compounds

    International Nuclear Information System (INIS)

    Certain biologically active nitrogenous compounds such as alkaloids are widely distributed in many wild and medicinal plants such as peganum harmala L. (Phycophyllaceae). However, less literature cited on the natural compounds was extracted from the aerial parts of this plant; therefore this study was conducted on harmal leaves using several solvents. Data indicated that methanol extract was the inhibitoriest effect against some pathogenic bacteria, particularly Streptococcus pyogenus. Chromatographic separation illustrated that presence of four compounds; the most active one was the third compound (3). Elementary analysis (C, H, N) revealed that the primary chemical structure of the active antibacterial compound (C3) was: C17 H21 N3 O7 S with molecular weight 411. Spectroscopic analysis proved that coninical structure was = 1- thioformyl, 8?- D glucoperanoside- Bis- 2, 3 dihydroisopyridino pyrrol. This new compound is represented as a noval ?- carboline alkaloid compound

  15. Native and Alien Plant Species Richness Response to Soil Nitrogen and Phosphorus in Temperate Floodplain and Swamp Forests

    Directory of Open Access Journals (Sweden)

    Richard Hrivnák

    2015-10-01

    Full Text Available Soil nitrogen and phosphorus are commonly limiting elements affecting plant species richness in temperate zones. Our species richness-ecological study was performed in alder-dominated forests representing temperate floodplains (streamside alder forests of Alnion incanae alliance and swamp forests (alder carrs of Alnion glutinosae alliance in the Western Carpathians. Species richness (i.e., the number of vascular plants in a vegetation plot was analyzed separately for native and alien vascular plants in 240 vegetation plots across the study area covering Slovakia, northern Hungary and southern Poland. The relationship between the species richness of each plant group and total soil nitrogen content, plant-available phosphorus and carbon to nitrogen (C/N ratio was analyzed by generalized linear mixed models (GLMM with Poisson error distribution and log-link function. The number of recorded native and alien species was 17–84 (average 45.4 and 0–9 (average 1.5 species per plot, respectively. The GLMMs were statistically significant (p ˂ 0.001 for both plant groups, but the total explained variation was higher for native (14% than alien plants (9%. The richness of native species was negatively affected by the total soil nitrogen content and plant-available phosphorus, whereas the C/N ratio showed a positive impact. The alien richness was predicted only by the total soil nitrogen content showing a negative effect.

  16. Identifying the active site in nitrogen-doped graphene for the VO2+/VO2(+) redox reaction.

    Science.gov (United States)

    Jin, Jutao; Fu, Xiaogang; Liu, Qiao; Liu, Yanru; Wei, Zhiyang; Niu, Kexing; Zhang, Junyan

    2013-06-25

    Nitrogen-doped graphene sheets (NGS), synthesized by annealing graphite oxide (GO) with urea at 700-1050 °C, were studied as positive electrodes in a vanadium redox flow battery. The NGS, in particular annealed at 900 °C, exhibited excellent catalytic performance in terms of electron transfer (ET) resistance (4.74 ± 0.51 and 7.27 ± 0.42 Ω for the anodic process and cathodic process, respectively) and reversibility (ΔE = 100 mV, Ipa/Ipc = 1.38 at a scan rate of 50 mV s(-1)). Detailed research confirms that not the nitrogen doping level but the nitrogen type in the graphene sheets determines the catalytic activity. Among four types of nitrogen species doped into the graphene lattice including pyridinic-N, pyrrolic-N, quaternary nitrogen, and oxidic-N, quaternary nitrogen is verified as a catalytic active center for the [VO](2+)/[VO2](+) couple reaction. A mechanism is proposed to explain the electrocatalytic performance of NGS for the [VO](2+)/[VO2](+) couple reaction. The possible formation of a N-V transitional bonding state, which facilitates the ET between the outer electrode and reactant ions, is a key step for its high catalytic activity.

  17. Nitrogen use efficiency by a slow-growing species as affected by CO2 levels, root temperature, N source and availability.

    Science.gov (United States)

    Cruz, Cristina; Lips, Herman; Martins-Loução, Maria Amélia

    2003-12-01

    This study examines the importance of N source and concentration on plant response to distinct CO2 concentrations and root temperatures. The experimental design of this work was a factorial combination of: CO2 concentration, nitrogen concentration, nitrogen source and root temperature. Carob (Ceratonia siliqua L.) was assessed as a potential model of a slow growing Mediterranean species. The results showed that: 1) biomass increment under high CO2 varied between 13 and 100% in relation to plants grown under the same conditions but at ambient CO2 concentrations, depending on the root temperature and nitrogen source; 2) nitrate-fed plants attained a larger increase in biomass production compared to ammonium-fed ones. This performance seems to be linked to the co-ordinated regulation of the activities of glutamine synthetase and sucrose phosphate synthase. The variations in the magnitude and nature of growth responses to elevated CO2 observed resulted in substantial changes in the chemical composition of the plant material and consequently in plant nitrogen use efficiency. Although performed with seedlings and under controlled conditions, this work emphasizes the importance of the nitrogen source used by the plants, a factor rarely taken into consideration when forecasting plant responses to global changes. Particularly, the results presented here, highlight the potential for uncoupling biomass accumulation from increment of air CO2 concentration and show that more than nitrogen availability N source may offset positive plant growth responses under elevated CO2 and root temperature.

  18. Antimicrobial activities of selected Cyathus species.

    Science.gov (United States)

    Liu, Ya-Jun; Zhang, Ke-Qin

    2004-02-01

    Twelve selected Cyathus species were tested for their abilities to produce antimicrobial metabolites. Most of them were found to produce secondary exo-metabolites that could induce morphological abnormalities of rice pathogenic fungi Pyricularia oryzae. Some extracts from the cultivated liquid obviously inhibited human pathogenic fungi Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans. Activities against six human pathogenic bacteria were also obtained from some of these extracts. PMID:15119855

  19. Production characteristics of reactive oxygen/nitrogen species in water using atmospheric pressure discharge plasmas

    Science.gov (United States)

    Takahashi, Kazuhiro; Satoh, Kohki; Itoh, Hidenori; Kawaguchi, Hideki; Timoshkin, Igor; Given, Martin; MacGregor, Scott

    2016-07-01

    A pulsed discharge, a DC corona discharge, and a plasma jet are separately generated above a water surface, and reactive oxygen species and reactive nitrogen species (ROS/RNS) in the water are investigated. ROS/RNS in water after the sparging of the off-gas of a packed-bed dielectric barrier discharge (PB-DBD) are also investigated. H2O2, NO2 ‑, and NO3 ‑ are detected after plasma exposure and only NO3 ‑ after off-gas sparging. Short-lifetime species in plasma are found to play an important role in H2O2 and NO2 ‑ production and long-lifetime species in NO3 ‑ production. NO x may inhibit H2O2 production through OH consumption to produce HNO2 and HNO3. O3 does not contribute to ROS/RNS production. The pulsed plasma exposure is found to be effective for the production of H2O2 and NO2 ‑, and the off-gas sparging of the PB-DBD for the production of NO3 ‑.

  20. Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Suschka Jan

    2014-07-01

    Full Text Available Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

  1. Nitrogen-Containing Apigenin Analogs: Preparation and Biological Activity

    Directory of Open Access Journals (Sweden)

    Jinyi Wang

    2012-12-01

    Full Text Available A series of nitrogen-containing apigenin analogs 4a–j was synthesized via Mannich reactions to develop anticancer, antibacterial, and antioxidant agents from plant-derived flavonoids. The chemical structures of these compounds were confirmed using 1H-NMR, 13C-NMR, and ESI-MS. The in vitro biological activities of the analogs were evaluated via assays of their antiproliferative, antibacterial, and antioxidant activities. The prepared apigenin analogs exhibited different antiproliferative activities against four human cancer cell lines, namely human cervical (HeLa, human hepatocellular liver (HepG2, human lung (A549, and human breast (MCF-7 cancer cells. Compound 4i showed the most favorable in vitro antiproliferative activity with IC50 values of 40, 40, 223, and 166 μg/mL against HeLa, HepG2, A549, and MCF-7, respectively. The 1,1-diphenyl-2-picrylhydrazyl (DPPH free radical scavenging activity assay also showed that 4i had the most potent antioxidant activity, with the smallest IC50 value (334.8 μg/mL. The antibacterial activities of the analogs were determined using a two-fold serial dilution technique against four pathogenic bacteria, namely Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. All the prepared apigenin analogs exhibited more potent activities than the parent apigenin. Compounds 4h and 4j, in particular, exhibited the best inhibitory activities against the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with MIC values of 3.91 and 1.95 μg/mL, respectively.

  2. Role of nitrogen in pore development in activated carbon prepared by potassium carbonate activation of lignin

    Science.gov (United States)

    Tsubouchi, Naoto; Nishio, Megumi; Mochizuki, Yuuki

    2016-05-01

    The present work focuses on the role of nitrogen in the development of pores in activated carbon produced from lignin by K2CO3 activation, employing a fixed bed reactor under a high-purity He stream at temperatures of 500-900 °C. The specific surface area and pore volume obtained by activation of lignin alone are 230 m2/g and 0.13 cm3/g at 800 °C, and 540 m2/g and 0.31 cm3/g at 900 °C, respectively. Activation of a mixture of lignin and urea provides a significant increase in the surface area and volume, respectively reaching 3300-3400 m2/g and 2.0-2.3 cm3/g after holding at 800-900 °C for 1 h. Heating a lignin/urea/K2CO3 mixture leads to a significant decrease in the yield of released N-containing gases compared to the results for urea alone and a lignin/urea mixture, and most of the nitrogen in the urea is retained in the solid phase. X-ray photoelectron spectroscopy and X-ray diffraction analyses clearly show that part of the remaining nitrogen is present in heterocyclic structures (for example, pyridinic and pyrrolic nitrogen), and the rest is contained as KOCN at ≤600 °C and as KCN at ≥700 °C, such that the latter two compounds can be almost completely removed by water washing. The fate of nitrogen during heating of lignin/urea/K2CO3 and role of nitrogen in pore development in activated carbon are discussed on the basis of the results mentioned above.

  3. Diversity and antibacterial activity of phyllosticta species

    Directory of Open Access Journals (Sweden)

    E. Chukeatirote

    2015-01-01

    Full Text Available Phyllosticta fungi are widely distributed and appear to have different lifestyles. Although some Phyllosticta species are known to cause plant diseases, others are useful due to their bioactive metabolites. In this study, we screened and isolated the Phyllosticta fungi from several plant specimens. In total, 67 Phyllosticta isolates were identified based on their distinct morphological characteristics. Of these, 18 isolates were pathogens and 49 isolates were endophytes. Besides, 61 isolates (91% were identified as P. capitalensis indicating its widespread distribution. Thirty Phyllosticta isolates were then selected for studying their antibacterial activity. For this, the fungal strains were cultured in potato dextrose broth and cultivated at 27 C for 2 weeks. The fungal mycelia were removed and the culture supernatants were extracted using ethyl acetate. Antibacterial activity screening was then carried out using an agar disc diffusion assay. Our data showed that most Phyllosticta crude extracts (87% were active and could inhibit at least one of the testing bacteria.

  4. The interaction between nitrogen and phosphorous is a strong predictor of intra-plant variation in nitrogen isotope composition in a desert species

    Science.gov (United States)

    Zhang, J.; Gu, L.; Zhang, J.; Wu, R.; Wang, F.; Lin, G.; Wu, B.; Lu, Q.; Meng, P.

    2015-11-01

    Understanding intra-plant variations in δ15N, which can be large, is essential for fully utilizing the role of δ15N as an integrator of the terrestrial nitrogen cycle. Studying such variations can yield insights into nitrogen metabolisms by the plant as a whole or by specific plant organs. However, systematical evaluation of intra-plant variations in δ15N and their relationship with organ nutrient contents is rare. We excavated whole plant architectures of Nitraria tangutorum Bobrov, a C3 species that has an exceptional capability of fixing sands and building sand dunes, in two deserts in northwestern China. We systematically and simultaneously measured nitrogen isotope ratios and nitrogen and phosphorous contents of different parts of the excavated plants. We found that intra-plant variations in δ15N of N. tangutorum were positively correlated with corresponding organ nitrogen (N) and phosphorous (P) contents. However, it was the N × P interaction, not N and P individually or their linear combination, that was the strongest predictor of intra-plant δ15N. We hypothesized that this strong positive intra-plant δ15N-N/P relationship was caused by fractionating gaseous N losses (volatilization) from plants and that the volatilization depended on the interaction between organ N and P contents. We also showed that root δ15N increased with depth into soil. This pattern was similar to profiles of soil δ15N reported by previous studies in different ecosystems although the exact relationship between root and soil profiles in δ15N was not clear. Studies of intra-plant variations in δ15N in different species, ecosystems, and climates and measurements of plant nitrogen volatilization and associated isotope fractionation are needed in order to determine the exact mechanisms responsible for the significant patterns first reported in this study.

  5. On the electrocatalytic activity of nitrogen-doped reduced graphene Oxide:Does the nature of nitrogen really control the activity towards oxygen reduction?

    Indian Academy of Sciences (India)

    Sourav Bag; Retna Raj C

    2016-03-01

    Synthesis of metal-free electrocatalyst for the cathodic reduction of oxygen is of great interest forfuel cell and metal-air battery applications. The heteroatom-doped graphene/reduced graphene oxide (rGO)is very promising and the nitrogen-doped rGO (N-rGO) is emerging as a new inexpensive electrocatalyst foroxygen reduction reaction (ORR). Herein, we describe the effect of the chemical nature and amount of nitrogenin N-rGO towards ORR in acidic solution. Four different samples of N-rGO with different nitrogen contentwere synthesized by simple chemical route. The chemical nature and nitrogen content were analyzed with Xray photoelectron spectroscopic measurements. The electrocatalytic performance of the catalyst was examinedby cyclic and hydrodynamic voltammetric studies. All the N-rGO samples favor 4-electron pathway for thereduction of oxygen in acidic solution. The onset potential and kinetic current density depends on the nature ofthe doped nitrogen. It is demonstrated that the chemical nature and the amount of nitrogen actually control theORR activity. The N-rGO which contains a large amount of pyridinic nitrogen with N/C ratio of 0.074 has highcatalytic activity. The carbon bonded to pyridinic nitrogen could be a possible catalytic site in ORR. Our studiessuggest that the graphitic nitrogen does not significantly influence the electrocatalytic activity of N-rGO.

  6. Plant nutrient acquisition strategies in tundra species: at which soil depth do species take up their nitrogen?

    Science.gov (United States)

    Limpens, Juul; Heijmans, Monique; Nauta, Ake; van Huissteden, Corine; van Rijssel, Sophie

    2016-04-01

    The Arctic is warming at unprecedented rates. Increased thawing of permafrost releases nutrients locked up in the previously frozen soils layers, which may initiate shifts in vegetation composition. The direction in which the vegetation shifts will co-determine whether Arctic warming is mitigated or accelerated, making understanding successional trajectories urgent. One of the key factors influencing the competitive relationships between plant species is their access to nutrients, in particularly nitrogen (N). We assessed the depth at which plant species took up N by performing a 15N tracer study, injecting 15(NH4)2SO4 at three depths (5, 15, 20 cm) into the soil in arctic tundra in north-eastern Siberia in July. In addition we explored plant nutrient acquisition strategy by analyzing natural abundances of 15N in leaves. We found that vascular plants took up 15N at all injection depths, irrespective of species, but also that species showed a clear preference for specific soil layers that coincided with their functional group (graminoids, dwarf shrubs, cryptogams). Graminoids took up most 15N at 20 cm depth nearest to the thaw front, with grasses showing a more pronounced preference than sedges. Dwarf shrubs took up most 15N at 5 cm depth, with deciduous shrubs displaying more preference than evergreens. Cryptogams did not take up any of the supplied 15N . The natural 15N abundances confirmed the pattern of nutrient acquisition from deeper soil layers in graminoids and from shallow soil layers in both deciduous and evergreen dwarf shrubs. Our results prove that graminoids and shrubs differ in their N uptake strategies, with graminoids profiting from nutrients released at the thaw front, whereas shrubs forage in the upper soil layers. The above implies that graminoids, grasses in particular, will have a competitive advantage over shrubs as the thaw front proceeds and/or superficial soil layers dry out. Our results suggest that the vertical distribution of nutrients

  7. Genome size and ploidy influence angiosperm species' biomass under nitrogen and phosphorus limitation.

    Science.gov (United States)

    Guignard, Maïté S; Nichols, Richard A; Knell, Robert J; Macdonald, Andy; Romila, Catalina-Andreea; Trimmer, Mark; Leitch, Ilia J; Leitch, Andrew R

    2016-06-01

    Angiosperm genome sizes (GS) range c. 2400-fold, and as nucleic acids are amongst the most phosphorus- (P) and nitrogen (N)-demanding cellular biomolecules, we test the hypothesis that a key influence on plant biomass and species composition is the interaction between N and P availability and plant GS. We analysed the impact of different nutrient regimes on above-ground biomass of angiosperm species with different GS, ploidy level and Grime's C-S-R (competitive, stress-tolerant, ruderal) plant strategies growing at the Park Grass Experiment (Rothamsted, UK), established in 1856. The biomass-weighted mean GS of species growing on plots with the addition of both N and P fertilizer were significantly higher than that of plants growing on control plots and plots with either N or P. The plants on these N + P plots are dominated by polyploids with large GS and a competitive plant strategy. The results are consistent with our hypothesis that large genomes are costly to build and maintain under N and P limitation. Hence GS and ploidy are significant traits affecting biomass growth under different nutrient regimes, influencing plant community composition and ecosystem dynamics. We propose that GS is a critical factor needed in models that bridge the knowledge gap between biodiversity and ecosystem functioning. PMID:26875784

  8. Chemical Composition, Nitrogen Fractions and Amino Acids Profile of Milk from Different Animal Species.

    Science.gov (United States)

    Rafiq, Saima; Huma, Nuzhat; Pasha, Imran; Sameen, Aysha; Mukhtar, Omer; Khan, Muhammad Issa

    2016-07-01

    Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat (6.82%±0.04%), solid-not-fat (11.24%±0.02%), total solids (18.05%±0.05%), protein (5.15%±0.06%) and casein (3.87%±0.04%) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk (0.80%±0.03%), buffalo (0.68%±0.02%) and sheep (0.66%±0.02%) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow (108±2.3 mg/g), camel (96±2.2 mg/g) and buffalo (90±2.4 mg/g) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products. PMID:26954163

  9. Chemical Composition, Nitrogen Fractions and Amino Acids Profile of Milk from Different Animal Species

    Science.gov (United States)

    Rafiq, Saima; Huma, Nuzhat; Pasha, Imran; Sameen, Aysha; Mukhtar, Omer; Khan, Muhammad Issa

    2016-01-01

    Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat (6.82%±0.04%), solid-not-fat (11.24%±0.02%), total solids (18.05%±0.05%), protein (5.15%±0.06%) and casein (3.87%±0.04%) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk (0.80%±0.03%), buffalo (0.68%±0.02%) and sheep (0.66%±0.02%) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow (108±2.3 mg/g), camel (96±2.2 mg/g) and buffalo (90±2.4 mg/g) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products. PMID:26954163

  10. The Effect of Different Nitrogen Form on Key Enzyme Activity of Sugarbeet (Vulgaris L.) Carbon and Nitrogen Metabolism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This article analyses the effect of the proportion of the different nitrogen forms on key enzyme activity of carbon and nitrogen metabolism under the condition of nutritional water while Tian Yan-7 was used as experimental material. The result showed that nitrate reductase(NR) activity in the leaves gradually enhanced with the increase of NO-3. No matter in root or leaves ,glutamina synthetase (GS) activity first enhanced with increasing NH4+ when NH4+ was lower than that of NO-3 ,and GS activity was the highest when NH4+and NO3-was equal ,then GS activity declined with NH4+ increasing further. In the anaphase of growth ,synthetic activity in root of sucrose synthetase(SS) in the mixed NH4+ and NO3- was obviously highr than or NO3- alone. Both of the root and sugar yields were the highest when the proportion of NH4+ and NO3- was 1: 1.

  11. Phytochemistry and biological activities of Phlomis species.

    Science.gov (United States)

    Limem-Ben Amor, Ilef; Boubaker, Jihed; Ben Sgaier, Mohamed; Skandrani, Ines; Bhouri, Wissem; Neffati, Aicha; Kilani, Soumaya; Bouhlel, Ines; Ghedira, Kamel; Chekir-Ghedira, Leila

    2009-09-01

    The genus Phlomis L. belongs to the Lamiaceae family and encompasses 100 species native to Turkey, North Africa, Europe and Asia. It is a popular herbal tea enjoyed for its taste and aroma. Phlomis species are used to treat various conditions such as diabetes, gastric ulcer, hemorrhoids, inflammation, and wounds. This review aims to summarize recent research on the phytochemistry and pharmacological properties of the genus Phlomis, with particular emphasis on its ethnobotanical uses. The essential oil of Phomis is composed of four chemotypes dominated by monoterpenes (alpha-pinene, limonene and linalool), sesquiterpenes (germacrene D and beta-caryophyllene), aliphalic compounds (9,12,15-octadecatrienoic acid methyl ester), fatty acids (hexadecanoic acid) and other components (trans-phytol, 9,12,15-octadecatrien-1-ol). Flavonoids, iridoids and phenylethyl alcohol constitute the main compounds isolated from Phlomis extracts. The pharmacological activities of some Phlomis species have been investigated. They are described according to antidiabetic, antinociceptive, antiulcerogenic, protection of the vascular system, anti-inflammatory, antiallergic, anticancer, antimicrobial and antioxidant properties. PMID:19563875

  12. Species and rotation frequency influence soil nitrogen in simplified tropical plant communities.

    Science.gov (United States)

    Ewel, John J

    2006-04-01

    Among the many factors that potentially influence the rate at which nitrogen (N) becomes available to plants in terrestrial ecosystems are the identity and diversity of species composition, frequency of disturbance or stand turnover, and time. Replicated suites of investigator-designed communities afforded an opportunity to examine the effects of those factors on net N mineralization over a 12-year period. The communities consisted of large-stature perennial plants, comprising three tree species (Hyeronima alchorneoides, Cedrela odorata, and Cordia alliodora), a palm (Euterpe oleracea), and a large, perennial herb (Heliconia imbricata). Trees were grown in monoculture and in combination with the other two life-forms; tree monocultures were subjected to rotations of one or four years, or like the three-life-form systems, left uncut. The work was conducted on fertile soil in the humid lowlands of Costa Rica, a site with few abiotic constraints to plant growth. Rates of net N mineralization and nitrification were high, typically in the range of 0.2-0.8 microg x g(1) x d(-1), with net nitrification slightly higher than net mineralization, indicating preferential uptake of ammonium (NH4+) by plants and microbes. Net rates of N mineralization were about 30% lower in stands of one of the three tree species, Hyeronima, than in stands of the other two. Contrary to expectations, short-rotation management (one or four years) resulted in higher net rates of N mineralization than in uncut stands, whether the latter were composed of a single tree species or a combination of life-forms. Neither additional species richness nor replenishment of leached N augmented mineralization rates. The net rate at which N was supplied tended to be lowest in stands where demand for N was highest. Careful choice of species, coupled with low frequency of disturbance, can lead to maintenance of N within biomass and steady rates of within-system circulation, whereas pulses, whether caused by cutting

  13. Species and rotation frequency influence soil nitrogen in simplified tropical plant communities.

    Science.gov (United States)

    Ewel, John J

    2006-04-01

    Among the many factors that potentially influence the rate at which nitrogen (N) becomes available to plants in terrestrial ecosystems are the identity and diversity of species composition, frequency of disturbance or stand turnover, and time. Replicated suites of investigator-designed communities afforded an opportunity to examine the effects of those factors on net N mineralization over a 12-year period. The communities consisted of large-stature perennial plants, comprising three tree species (Hyeronima alchorneoides, Cedrela odorata, and Cordia alliodora), a palm (Euterpe oleracea), and a large, perennial herb (Heliconia imbricata). Trees were grown in monoculture and in combination with the other two life-forms; tree monocultures were subjected to rotations of one or four years, or like the three-life-form systems, left uncut. The work was conducted on fertile soil in the humid lowlands of Costa Rica, a site with few abiotic constraints to plant growth. Rates of net N mineralization and nitrification were high, typically in the range of 0.2-0.8 microg x g(1) x d(-1), with net nitrification slightly higher than net mineralization, indicating preferential uptake of ammonium (NH4+) by plants and microbes. Net rates of N mineralization were about 30% lower in stands of one of the three tree species, Hyeronima, than in stands of the other two. Contrary to expectations, short-rotation management (one or four years) resulted in higher net rates of N mineralization than in uncut stands, whether the latter were composed of a single tree species or a combination of life-forms. Neither additional species richness nor replenishment of leached N augmented mineralization rates. The net rate at which N was supplied tended to be lowest in stands where demand for N was highest. Careful choice of species, coupled with low frequency of disturbance, can lead to maintenance of N within biomass and steady rates of within-system circulation, whereas pulses, whether caused by cutting

  14. Novel interactions of mitochondria and reactive oxygen/nitrogen species in alcohol mediated liver disease

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Mitochondrial dysfunction is known to be a contributing factor to a number of diseases including chronic alcohol induced liver injury. While there is a detailed understanding of the metabolic pathways and proteins of the liver mitochondrion, little is known regarding how changes in the mitochondrial proteome may contribute to the development of hepatic pathologies.Emerging evidence indicates that reactive oxygen and nitrogen species disrupt mitochondrial function through post-translational modifications to the mitochondrial proteome. Indeed, various new affinity labeling reagents are available to test the hypothesis that post-translational modification of proteins by reactive species contributes to mitochondrial dysfunction and alcoholic fatty liver disease. Specialized proteomic techniques are also now available, which allow for identification of defects in the assembly of multi-protein complexes in mitochondria and the resolution of the highly hydrophobic proteins of the inner membrane. In this review knowledge gained from the study of changes to the mitochondrial proteome in alcoholic hepatotoxicity will be described and placed into a mechanistic framework to increase understanding of the role of mitochondrial dysfunction in liver disease.

  15. Species-specific Response of Photosynthesis to Burning and Nitrogen Fertilization

    Institute of Scientific and Technical Information of China (English)

    Yanfang Zhang; Shuli Niu; Wenhua Xu; Yi Han

    2008-01-01

    The present study was conducted to examine photosynthetic characteristics of three dominant grass species (Agropyron cristatum, Leymus chinensis, and Cleistogenes squarrosa) and their responses to burning and nitrogen fertilization in a semiarid grassland in northern China. Photosynthetic rate (Pn), stomatal conductance (gs), and water use efficiency (WUE) showed strong temporal variability over the growing season. C. squarrosa showed a significantly higher Pn and WUE than A. cristatum and L. chinensis. Burning stimulated Pn of A. cristatum and L. chinensis by 24-59% (P<0.05) in the early growing season, but not during other time periods. Light-saturated photosynthetic rate (φmax) in A. cristatum C. squarrosa. The burning-induced changes in soil moisture could explain 51% (P=0.01) of the burning-induced changes The stimulation of Pn under N fertilization was mainly observed in the early growing season when the soil extractable N content was significantly higher in the fertilized plots. The N fertilization-induced changes in soil extractable N content could explain 66% (P=0.001) of the changes in Pn, under N fertilization. The photosynthetic responses of the three species indicate that burning and N fertilization will potentially change the community structure and ecosystem productivity in the semiarid grasslands of northern China.

  16. Adsorption kinetics and equilibrium study of nitrogen species onto radiata pine (Pinus radiata) sawdust.

    Science.gov (United States)

    Harmayani, Kadek D; Faisal Anwar, A H M

    2016-01-01

    Nitrogen species (NH3-N, NO3-N, and NO2-N) are found as one of the major dissolved constituents in wastewater or stormwater runoff. In this research, laboratory experiments were conducted to remove these pollutants from the water environment using radiata pine (Pinus radiata) sawdust. A series of batch tests was conducted by varying initial concentration, dosage, particle size, pH, and contact time to check the removal performance. Test results confirmed the effectiveness of radiata pine sawdust for removing these contaminants from the aqueous phase (100% removal of NO3-N, and NO2-N; 55% removal of NH3-N). The adsorbent dosage and initial concentration showed a significantly greater effect on the removal process over pH or particle sizes. The optimum dosage for contaminant removal on a laboratory scale was found to be 12 g. Next, the adsorption kinetics were studied using intraparticle diffusion, liquid-film diffusion, and a pseudo-first order and pseudo-second order model. The adsorption of all species followed a pseudo-second order model but NO2-N adsorption followed both models. In addition, the kinetics of NO2-N adsorption showed two-step adsorption following intraparticle diffusion and liquid-film diffusion. The isotherm study showed that NO3-N and NO2-N adsorption fitted slightly better with the Freundlich model but that NH3-N adsorption followed both Freundlich and Langmuir models. PMID:27438245

  17. Preference for different inorganic nitrogen forms among plant functional types and species of the Patagonian steppe.

    Science.gov (United States)

    Gherardi, Laureano A; Sala, Osvaldo E; Yahdjian, Laura

    2013-11-01

    We have explored species-specific preferences for nitrate (NO3(-)) and ammonium (NH4(+)) as an alternative niche separation in ecosystems where nitrogen (N) is present mostly in inorganic forms. The Patagonian steppe is dominated by shrubs and grasses. Shrubs absorb water and nutrients from deep soil layers, which are poor in N, while grasses have the opposite pattern, absorbing most of their water and nutrients from the upper layers of the soil. We hypothesized that the preferences of shrub and grass for inorganic N forms are different and that the rate of potential N uptake is greater in shrubs than in grasses. To test this hypothesis, we grew individuals of six dominant species in solutions of different NH4(+):NO3(-) concentration ratios. Nitrate uptake was found to be higher in shrubs, while ammonium uptake was similar between plant functional types. The NH4(+):NO3(-) uptake ratio was significantly lower for shrubs than grasses. Shrubs, which under field conditions have deeper rooting systems than grasses, showed a higher N absorption capacity than grasses and a preference for the more mobile N form, nitrate. Grasses, which had lower N uptake rates than shrubs, preferred ammonium over nitrate. These complementary patterns between grasses and shrubs suggest a more thorough exploitation of resources by diverse ecosystems than those dominated by just one functional type. The loss of one plant functional group or a significant change in its abundance would therefore represent a reduction in resource use efficiency and ecosystem functioning. PMID:23812108

  18. Gaetice depressus (Crustacea, Varunidae): Species profile and its role in organic carbon and nitrogen flow

    Science.gov (United States)

    Wahyudi, A'an. J.; Wada, Shigeki; Aoki, Masakazu; Hama, Takeo

    2015-06-01

    Gaetice depressus is one of the most dominant macrozoobenthos species in boulder shores of intertidal coastal ecosystems in Japan. As recorded in previous studies, this species is also considered as having high density and biomass. Consequently, it is thought to be one of the more important species in the organic matter flow of boulder shores, especially through the food web. In this study, some taxonomic problems related to G. depressus were tackled and the autoecology and ecological processes in the intertidal ecosystem of G. depressus, such as organic matter flow, were investigated. Furthermore, in order to clarify the taxonomy description, resolve inconsistencies in the scientific name, and learn about the life history, a literature review was conducted. Seasonal changes in density, morphology pattern and population structure were determined based on the data obtained in Ebisu Island, Japan. Then, the role of G. depressus was determined by estimating the intake and emittance fluxes of organic carbon and nitrogen through ingestion and egestion process in the boulder shores of Ebisu Island. A feeding rate experiment was also conducted in order to estimate the intake flux by using the catch-release-recapture method. Meanwhile, to estimate the emittance flux, a defecation rate experiment was conducted by catching some individuals of G. depressus, and then incubating them in the laboratory. The feeding rate measured by the speed of diet consumption of G. depressus was about 12.6 mg ind-1 h-1. Considering the average density, the intake flux through the feeding process could be estimated as 25.2 mgC m-2 h-1 and 2.6 mgN m-2 h-1. On the other hand, G. depressus egested fecal pellet at the rate of 5.4 mg ind-1 h-1. The average emittance flux through the fecal pellet egesting process is estimated at 5.6 mgC m-2 h-1 and 0.7 mgN m-2 h-1. Therefore, it can be estimated that about 25% of organic matter from diet is egested as fecal pellet, which means that about 75% of the

  19. Oxidation of diclofenac with chlorine dioxide in aquatic environments: influences of different nitrogenous species.

    Science.gov (United States)

    Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai; Ni, Tianjun

    2015-06-01

    The oxidation of diclofenac (DCF), a non-steroidal anti-inflammatory drug and emerging water pollutant, with chlorine dioxide was investigated under simulated water disinfection conditions. The reaction kinetics as functions of the initial concentrations of DCF, different nitrogenous species, and different pE values were experimentally determined. The results demonstrated that DCF reacted rapidly with ClO2, where more than 75 % of DCF (≤3.00 μM) was removed by 18.94 μM ClO2 within 60 s. All of the reactions followed pseudo first-order kinetics with respect to DCF, and the rate constant, k obs, exhibited a significant decrease from 4.21 × 10(-2) to 8.09 × 10(-3) s(-1), as the initial DCF concentration was increased from 1.00 to 5.00 μM. Furthermore, the degradation kinetics of DCF was clearly dependent on nitrogen-containing ion concentrations in the reaction solution. Ammonium and nitrite ions inhibited the DCF degradation by ClO2, whereas nitrate ion clearly initiated its promotion. In contrast, the inhibitory effect of NO2 (-) was more robust than that of NH4 (+). When the values of pE were gradually increased, the transformation of NH4 (+) to NO2 (-), and subsequently to NO3 (-), would occur, the rate constants were initially decreased, and then increased. When NH4 (+) and NO2 (-) coexisted, the inhibitory effect on the DCF degradation was less than the sum of the partial inhibitory effect. However, when NO2 (-) and NO3 (-) coexisted, the actual inhibition rate was greater than the theoretical estimate. These results indicated that the interaction of NH4 (+) and NO2 (-) was antagonistic, while the coexistence of NO2 (-) and NO3 (-) was observed to have a synergistic effect in aqueous environments. PMID:25604564

  20. Biofilter design for effective nitrogen removal from stormwater - influence of plant species, inflow hydrology and use of a saturated zone.

    Science.gov (United States)

    Payne, Emily G I; Pham, Tracey; Cook, Perran L M; Fletcher, Tim D; Hatt, Belinda E; Deletic, Ana

    2014-01-01

    The use of biofilters to remove nitrogen and other pollutants from urban stormwater runoff has demonstrated varied success across laboratory and field studies. Design variables including plant species and use of a saturated zone have large impacts upon performance. A laboratory column study of 22 plant species and designs with varied outlet configuration was conducted across a 1.5-year period to further investigate the mechanisms and influences driving biofilter nitrogen processing. This paper presents outflow concentrations of total nitrogen from two sampling events across both 'wet' and 'dry' frequency dosing, and from sampling across two points in the outflow hydrograph. All plant species were effective under conditions of frequent dosing, but extended drying increased variation between species and highlighted the importance of a saturated zone in maintaining biofilter function. The saturated zone also effectively treated the volume of stormwater stored between inflow events, but this extended detention provided no additional benefit alongside the rapid processing of the highest performing species. Hence, the saturated zone reduced performance differences between plant species, and potentially acts as an 'insurance policy' against poor sub-optimal plant selection. The study shows the importance of biodiversity and inclusion of a saturated zone in protecting against climate variability.

  1. Base cation depletion, eutrophication and acidification of species-rich grasslands in response to long-term simulated nitrogen deposition

    International Nuclear Information System (INIS)

    Pollutant nitrogen deposition effects on soil and foliar element concentrations were investigated in acidic and limestone grasslands, located in one of the most nitrogen and acid rain polluted regions of the UK, using plots treated for 8-10 years with 35-140 kg N ha-2 y-1 as NH4NO3. Historic data suggests both grasslands have acidified over the past 50 years. Nitrogen deposition treatments caused the grassland soils to lose 23-35% of their total available bases (Ca, Mg, K, and Na) and they became acidified by 0.2-0.4 pH units. Aluminium, iron and manganese were mobilised and taken up by limestone grassland forbs and were translocated down the acid grassland soil. Mineral nitrogen availability increased in both grasslands and many species showed foliar N enrichment. This study provides the first definitive evidence that nitrogen deposition depletes base cations from grassland soils. The resulting acidification, metal mobilisation and eutrophication are implicated in driving floristic changes. - Nitrogen deposition causes base cation depletion, acidification and eutrophication of semi-natural grassland soils

  2. Formation of reactive nitrogen species at biologic heme centers: a potential mechanism of nitric oxide-dependent toxicity.

    Science.gov (United States)

    Casella, Luigi; Monzani, Enrico; Roncone, Raffaella; Nicolis, Stefania; Sala, Alberto; De Riso, Antonio

    2002-01-01

    The peroxidase-catalyzed nitration of tyrosine derivatives by nitrite and hydrogen peroxide has been studied in detail using the enzymes lactoperoxidase (LPO) from bovine milk and horseradish peroxidase (HRP). The results indicate the existence of two competing pathways, in which the nitrating species is either nitrogen dioxide or peroxynitrite. The first pathway involves one-electron oxidation of nitrite by the classical peroxidase intermediates compound I and compound II, whereas in the second pathway peroxynitrite is generated by reaction between enzyme-bound nitrite and hydrogen peroxide. The two mechanisms can be simultaneously operative, and their relative importance depends on the reagent concentrations. With HRP the peroxynitrite pathway contributes significantly only at relatively high nitrite concentrations, but for LPO this represents the main pathway even at relatively low (pathophysiological) nitrite concentrations and explains the high efficiency of the enzyme in the nitration. Myoglobin and hemoglobin are also active in the nitration of phenolic compounds, albeit with lower efficiency compared with peroxidases. In the case of myoglobin, endogenous nitration of the protein has been shown to occur in the absence of substrate. The main nitration site is the heme, but a small fraction of nitrated Tyr146 residue has been identified upon proteolytic digestion and high-performance liquid chromatography/mass spectrometry analysis of the peptide fragments. Preliminary investigation of the nitration of tryptophan derivatives by the peroxidase/nitrite/hydrogen peroxide systems shows that a complex pattern of isomeric nitration products is produced, and this pattern varies with nitrite concentration. Comparative experiments using chemical nitrating agents indicate that at low nitrite concentrations, the enzymatic nitration produces a regioisomeric mixture of nitrotryptophanyl derivatives resembling that obtained using nitrogen dioxide, whereas at high nitrite

  3. Inhibitory effect of ammonia nitrogen on specific methanogenic activity of anaerobic granular sludge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed(UASB) and expanded granular sludge bed(EGSB) reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50% inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia nitrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.

  4. Regulation of sucrose synthase activity and sugar yield by nitrogen in sugar beet

    Institute of Scientific and Technical Information of China (English)

    LI Caifeng; MA Fengming; LI Wenhua; WANG Rui; CHEN Shengyong; LUO Yu

    2007-01-01

    The content of sugar is influenced by sucrose synthase (SS) activity in roots. The effects of nitrogen level in the aminonitrate ratio on SS activity of leaves and roots, roots yield and sugar content in sugar beet were studied in the field experiment by nutrient solution culture. The results showed that SS activity in leaves was lower than that in roots. With nitrogen level increasing,SS decomposition activity enhanced, and synthesis activity reduced. SS activity was regulated by different nitrogen forms and the ratio of NO3- and NH4+. SS synthesis activity was enhanced as NH4+ increasing when NO3-: NH4+≥ 1, and it decreased as increasing NH4+ when NO3-: NH4+≤1, and it was the highest when NO3-: NH4+=1. SS decomposition activity was enhanced as NO3- increasing.Sucrose content in root was lowed as nitrogen level increasing, but it was enhanced as NH4+ increasing in the same nitrogen level.Root and sugar yield were the highest in the medium nitrogen level and NO3-: NH4+=1. The result in field experiment corresponded with that in the nutrient fluid culture. It provides a basis for using reasonably nitrogen fertilizer in sugar beet production.

  5. Reactive oxygen and nitrogen species induce protein and DNA modifications driving arthrofibrosis following total knee arthroplasty

    Directory of Open Access Journals (Sweden)

    Freeman Theresa A

    2009-11-01

    Full Text Available Abstract Background Arthrofibrosis, occurring in 3%-4% of patients following total knee arthroplasty (TKA, is a challenging condition for which there is no defined cause. The hypothesis for this study was that disregulated production of reactive oxygen species (ROS and nitrogen species (RNS mediates matrix protein and DNA modifications, which result in excessive fibroblastic proliferation. Results We found increased numbers of macrophages and lymphocytes, along with elevated amounts of myeloperoxidase (MPO in arthrofibrotic tissues when compared to control tissues. MPO expression, an enzyme that generates ROS/RNS, is usually limited to neutrophils and some macrophages, but was found by immunohistochemistry to be expressed in both macrophages and fibroblasts in arthrofibrotic tissue. As direct measurement of ROS/RNS is not feasible, products including DNA hydroxylation (8-OHdG, and protein nitrosylation (nitrotyrosine were measured by immunohistochemistry. Quantification of the staining showed that 8-OHdg was significantly increased in arthrofibrotic tissue. There was also a direct correlation between the intensity of inflammation and ROS/RNS to the amount of heterotopic ossification (HO. In order to investigate the aberrant expression of MPO, a real-time oxidative stress polymerase chain reaction array was performed on fibroblasts isolated from arthrofibrotic and control tissues. The results of this array confirmed the upregulation of MPO expression in arthrofibrotic fibroblasts and highlighted the downregulated expression of the antioxidants, superoxide dismutase1 and microsomal glutathione S-transferase 3, as well as the significant increase in thioredoxin reductase, a known promoter of cell proliferation, and polynucleotide kinase 3'-phosphatase, a key enzyme in the base excision repair pathway for oxidative DNA damage. Conclusion Based on our current findings, we suggest that ROS/RNS initiate and sustain the arthrofibrotic response driving

  6. Targeting reactive nitrogen species: a promising therapeutic strategy for cerebral ischemia-reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    Xing-miao CHEN; Han-sen CHEN; Ming-jing XU; Jian-gang SHEN

    2013-01-01

    Ischemic stroke accounts for nearly 80% of stroke cases.Recanalization with thrombolysis is a currently crucial therapeutic strategy for re-building blood supply,but the thrombolytic therapy often companies with cerebral ischemia-reperfusion injury,which are mediated by free radicals.As an important component of free radicals,reactive nitrogen species (RNS),including nitric oxide (NO) and peroxynitrite (ONO0ˉ),play important roles in the process of cerebral ischemia-reperfusion injury.Ischemia-reperfusion results in the production of nitric oxide (NO) and peroxynitrite (ONOOˉ) in ischemic brain,which trigger numerous molecular cascades and lead to disruption of the blood brain barrier and exacerbate brain damage.There are few therapeutic strategies available for saving ischemic brains and preventing the subsequent brain damage.Recent evidence suggests that RNS could be a therapeutic target for the treatment of cerebral ischemia-reperfusion injury.Herein,we reviewed the recent progress regarding the roles of RNS in the process of cerebral ischemic-reperfusion injury and discussed the potentials of drug development that target NO and ONO0ˉ to treat ischemic stroke.We conclude that modulation for RNS level could be an important therapeutic strategy for preventing cerebral ischemiareperfusion injury.

  7. Euedaphic and hemiedaphic Collembola suffer larger damages than epedaphic species to nitrogen input.

    Science.gov (United States)

    Song, Lihong; Liu, Jing; Yan, Xiumin; Chang, Liang; Wu, Donghui

    2016-01-01

    Wetlands are commonly limited in available nitrogen. But marshes in the Sanjiang Plain, Northeastern China suffer large amounts of exogenous nitrogen from agriculture fertilization after wetland reclamation. This paper focuses on the ecological effects of a short-term increase of nitrogen input on collembolan communities. Our results show a significant decrease in collembolan abundance and Shannon diversity index, and the abundance of euedaphic and hemiedaphic collembolans decreased faster than epedaphic collembolans. These results indicate that euedaphic or hemiedaphic fauna suffer more biodiversity loss caused by nitrogen deposition than epedaphic fauna and call for more researches on trait-based approaches under environmental stress in the future. PMID:26549750

  8. Bioavailable and biodegradable dissolved organic nitrogen in activated sludge and trickling filter wastewater treatment plants

    Science.gov (United States)

    A study was carried out to understand the fate of biodegradable dissolved organic nitrogen (BDON) and bioavailable dissolved organic nitrogen (ABDON) along the treatment trains of a wastewater treatment facility (WWTF) equipped with an activated sludge (AS) system and a WWTF equipped with a two-stag...

  9. Elevated stream inorganic nitrogen impacts on a dominant riparian tree species: Results from an experimental riparian stream system

    Science.gov (United States)

    Hultine, K. R.; Jackson, T. L.; Burtch, K. G.; Schaeffer, S. M.; Ehleringer, J. R.

    2008-12-01

    The release of inorganic nitrogen from intensive agricultural practices and urbanization has resulted in significant alterations of the aquatic nitrogen cycle in riparian ecosystems. Nevertheless, impacts of stream nitrogen inputs on the terrestrial nitrogen cycle and the water and carbon cycles are unclear. Information on terrestrial ecosystem responses to stream N loading is largely absent in part because of the difficulty in controlling for temporal and spatial variation in streamflow, geomorphology, climate, and vegetation. To address these issues, we constructed a dual-plot artificial stream riparian system within a 10-year-old plantation of a dominant riparian tree species, box elder (Acer negundo). The dual-plot design allowed for different concentrations of stream inorganic nitrogen between plots while controlling for ecohydrologic and geohydrologic variability. The system was used to investigate elevated inorganic stream nitrogen impacts on water use patterns, above-ground productivity, and leaf chemistry of streamside box elder trees over two consecutive growing seasons (2006 and 2007). One plot received inorganic soluble fertilizer that brought the NO3 concentration of stream water from 5 μmol l-1 to about 100 μmol l-1, while the second plot received no additional nitrogen. Relative stem sap flux density (Js) did not vary between plots until near the conclusion of the 2006 growing season, when trees in the fertilized plot showed a steep upswing in Js relative to trees in the control plot. Sap flux in 2007 increased consistently by 0.4% day-1 in the fertilized plot relative to the control plot over a 75-day period, before leveling off near the conclusion of the growing season. At the onset of the experiment, leaf nitrogen per unit mass and leaf nitrogen per unit area were significantly higher in the control plot, and leaf C:N ratios were lower. In 2007, however, differences in leaf chemistry disappeared, suggesting that leaf nitrogen increased in the

  10. Reactivities of radicals of adenine and guanine towards reactive oxygen species and reactive nitrogen oxide species: OH rad and NO 2rad

    Science.gov (United States)

    Agnihotri, Neha; Mishra, P. C.

    2011-02-01

    Reactions of radicals of the DNA bases with reactive oxygen species and reactive nitrogen oxide species produce mutagenic products. We have studied reactivities of all the carbon sites of radicals of adenine A(-H) rad and guanine G(-H) rad obtained by removal of H-atoms from their nitrogen sites towards OH rad and NO 2rad . We studied stabilities of A(-H) rad and G(-H) rad and binding energies of their adducts with each of OH rad and NO 2rad using density functional theoretic and MP2 calculations employing the AUG-cc-pVDZ basis set. Solvation in aqueous media was treated using the polarization continuum model. The results obtained explain experimental observations.

  11. Nitrogen Mineralization of Prunings of Six N2-Fixing Hedgerow Species in a Dry Valley of the Jinsha River

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A litterbag experiment of 12 weeks was conducted to study nitrogen mineralization process of prunings of six nitrogen-fixing hedgerow species in a dry valley of the Jinsha River. Prunings were incorporated into soil or used as mulch. The results indicated that pruning N of the six hedgerow species was mineralized fast in the first week and then decreased slowly in the rest of the study period. When prunings were incorporated into soil, the amount of nitrogen mineralized by the end of the first week accounted for 69.9%, 58.2%, 54.5%,43.0%, 29.6% and 20.6% of the total N in prunings of Desmodium rensonii, Tephrosia candida, Leucaena leucocuphala, Albizia yunnanensis, Acacia dealbata, and Acacia mearnsii, respectively. When prunings of L. leucocephala were used as mulch materials, the amount of nitrogen mineralized in the first week was 16.2% less than that of prunings incorporated into soil. The mineralization pattern of pruning N could be simulated by an exponent model Nt% = N01% (1 - exp(-k1t))+ N02% (1 - exp(-k2t)) where Nt% is cumulative mineralized N in time t, N01% and N02 % are readily and less readily mineralizable N in prunings,respectively, and k1 and k2 are rate constants. A half-life period of pruning nitrogen mineralization could ~ be determined by this model. The nitrogen content in the pruning residues decreased quickly in the first week but fluctuated thereafter. The initial C/N ratio was negatively related to the mineralization rate of prunings.``

  12. Sensitivity of modeled atmospheric nitrogen species and nitrogen deposition to variations in sea salt emissions in the North Sea and Baltic Sea regions

    Science.gov (United States)

    Neumann, Daniel; Matthias, Volker; Bieser, Johannes; Aulinger, Armin; Quante, Markus

    2016-03-01

    Coarse sea salt particles are emitted ubiquitously from the ocean surface by wave-breaking and bubble-bursting processes. These particles impact the atmospheric chemistry by affecting the condensation of gas-phase species and, thus, indirectly the nucleation of new fine particles, particularly in regions with significant air pollution. In this study, atmospheric particle concentrations are modeled for the North Sea and Baltic Sea regions in northwestern Europe using the Community Multiscale Air Quality (CMAQ) modeling system and are compared to European Monitoring and Evaluation Programme (EMEP) measurement data. The sea salt emission module is extended by a salinity-dependent scaling of the sea salt emissions because the salinity in large parts of the Baltic Sea is very low, which leads to considerably lower sea salt mass emissions compared to other oceanic regions. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is considered separately. Additionally, the impacts of sea salt particles on atmospheric nitrate and ammonium concentrations and on nitrogen deposition are evaluated. The comparisons with observational data show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated farther inland. The introduced salinity scaling improves the predicted Baltic Sea sea salt concentrations considerably. The dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to minor increases in NH3 + NH4+ and HNO3 + NO3- and a decrease in NO3- concentrations. However, the overall effect on NH3 + NH4+ and HNO3 + NO3- concentrations is smaller than the deviation from the measurements. Nitrogen wet deposition is underestimated by the model at most

  13. Experimental and numerical investigations on nitrogen species transport in unsaturated soil during various irrigation patterns

    Indian Academy of Sciences (India)

    M Berlin; Indumathi M Nambi; G Suresh Kumar

    2015-12-01

    The transport of nitrogen coming from wastewater applied agricultural field is a major problem in assessing the vulnerability of groundwater contamination. In this study, laboratory column experiments are conducted in order to simulate the paddy, groundnut and wheat irrigation with wastewater. The experiments are carried out with high clay content (≈35%) soil from Kancheepuram, Tamilnadu and low clay (≈9%) soil from Ludhiana, Punjab, India. Furthermore, a numerical model and HYDRUS-1D model are developed to simulate the experimental results. The experimental results show that there is no effluent collected at the bottom of the column during groundnut irrigation in Kancheepuram soil and effluent collected except during first irrigation in the case of wheat irrigation in Ludhiana soil. The experimental and numerical results illustrate that when 50 mg/l of ammonium and 20 mg/l of nitrate nitrogen applied during paddy irrigation, the peak nitrate nitrogen concentration of 50 mg/l is arrived after 10 days in Kancheepuram soil due to low permeability and relatively less background soil nitrogen. But in the case of Ludhiana soil with 94 mg/l of total nitrogen applied during paddy irrigation, the peak nitrate nitrogen concentration of 1,620 mg/l is observed at first day due to high permeability and high soil background nitrogen concentration. Additionally, the model results show that the application of high nitrogen content wastewater for irrigation in Ludhiana soil will affect the groundwater quality even when the groundwater table is deep as compared with Kancheepuram soil.

  14. Reactive nitrogen species in acetaminophen-induced mitochondrial damage and toxicity in mouse hepatocytes.

    Science.gov (United States)

    Burke, Angela S; MacMillan-Crow, Lee Ann; Hinson, Jack A

    2010-07-19

    Acetaminophen (APAP) toxicity in primary mouse hepatocytes occurs in two phases. The initial phase (0-2 h) occurs with metabolism to N-acetyl-p-benzoquinoneimine which depletes glutathione, and covalently binds to proteins, but little toxicity is observed. Subsequent washing of hepatocytes to remove APAP and reincubating in media alone (2-5 h) results in toxicity. We previously reported that the reincubation phase occurs with mitochondrial permeability transition (MPT) and increased oxidative stress (dichlorodihydrofluorescein fluorescence) (DCFH(2)). Since DCFH(2) may be oxidized by multiple oxidative mechanisms, we investigated the role of reactive nitrogen species (RNS) leading to 3-nitrotyrosine in proteins by ELISA and by immunoblots. Incubation of APAP with hepatocytes for 2 h did not result in toxicity or protein nitration; however, washing hepatocytes and reincubating in media alone (2-5 h) resulted in protein nitration which correlated with toxicity. Inclusion of the MPT inhibitor, cyclosporine A, in the reincubation media eliminated toxicity and protein nitration. The general nitric oxide synthase (NOS) inhibitor L-NMMA and the neuronal NOS (NOS1) inhibitor, 7-nitroindazole, added in the reincubation media decreased toxicity and protein nitration; however, neither the inducible NOS (NOS2) inhibitors L-NIL (N6-(1-iminoethyl)-L-lysine) nor SAIT (S-(2-aminoethyl)isothiourea) decreased protein nitration or toxicity. The RNS scavengers, N-acetylcysteine, and high concentrations of APAP, added in the reincubation phase decreased toxicity and protein nitration. 7-Nitroindazole and cyclosporine A inhibited the APAP-induced loss of mitochondrial membrane potential when added in the reincubation phase. The data indicate a role for RNS in APAP induced toxicity.

  15. Incorporation of low energy activated nitrogen onto HOPG surface: Chemical states and thermal stability studies by in-situ XPS and Raman spectroscopy

    Science.gov (United States)

    Chandran, Maneesh; Shasha, Michal; Michaelson, Shaul; Hoffman, Alon

    2016-09-01

    In this paper we report the chemical states analysis of activated nitrogen incorporated highly oriented pyrolytic graphite (HOPG) surface under well-controlled conditions. Nitrogen incorporation is carried out by two different processes: an indirect RF nitrogen plasma and low energy (1 keV) N2+ implantation. Bonding configuration, concentration and thermal stability of the incorporated nitrogen species by aforesaid processes are systematically compared by in-situ X-ray photoelectron spectroscopy (XPS). Relatively large concentration of nitrogen is incorporated onto RF nitride HOPG surface (16.2 at.%), compared to N2+ implanted HOPG surface (7.7 at.%). The evolution of N 1s components (N1, N2, N3) with annealing temperature is comprehensively discussed, which indicates that the formation and reorganization of local chemical bonding states are determined by the process of nitridation and not by the prior chemical conditioning (i.e., amorphization or hydrogenation) of the HOPG surface. A combined XPS and Raman spectroscopy studies revealed that N2+ implantation process resulted in a high level of defects to the HOPG surface, which cannot be annealed-out by heat treatment up to 1000 °C. On the other hand, the RF nitrogen plasma process did not produce a high level of surface defects, while incorporating nearly the same amount of stable nitrogen species.

  16. Cars, Cows, and Checkerspot Butterflies: Nitrogen Deposition and Management of Nutrient-Poor Grasslands for a Threatened Species

    OpenAIRE

    Weiss, Stuart B.

    1999-01-01

    Nutrient-poor, serpentinitic soils in the San Francisco Bay area sustain a native grassland that supports many rare species, including the Bay checkerspot butterfly ( Euphydryas editha bayensis). Nitrogen (N) deposition from air pollution threatens biodiversity in these grasslands because N is the primary limiting nutrient for plant growth on serpentinitic soils. I investigated the role of N deposition through surveys of butterfly and plant populations across different grazing regimes, by lit...

  17. Seasonal Changes of Freshwater Ammonia-Oxidizing Archaeal Assemblages and Nitrogen Species in Oligotrophic Alpine Lakes▿ †

    OpenAIRE

    Auguet, Jean-Christophe; Nomokonova, Natalya; Camarero, Lluis; Casamayor, Emilio O.

    2011-01-01

    The annual changes in the composition and abundance of ammonia-oxidizing archaea (AOA) were analyzed monthly in surface waters of three high mountain lakes within the Limnological Observatory of the Pyrenees (LOOP; northeast Spain) using both 16S rRNA and functional (ammonia monooxygenase gene, amoA) gene sequencing as well as quantitative PCR amplification. The set of biological data was related to changes in nitrogen species and to other relevant environmental variables. The whole archaeal ...

  18. Theoretical evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process

    Institute of Scientific and Technical Information of China (English)

    ZHU Gui-bing; PENG Yong-zhen

    2006-01-01

    Evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process at the standpoint of reaction kinetics and process kinetics was conducted. Theoretical biological nitrogen removal efficiency was deduced based on the mass balance of nitrate in the last stage. The comparison of pre-denitrification process and step feed process in the aspects of nitrogen removal efficiency, volume of reactor and building investment was studied, and the results indicated that step-feed anoxic/oxic activated sludge process was superior to pre-denitrification process in these aspects.

  19. Model of Calculating Activity of Nitrogen and Vanadium in Fe-C-V-N Molten Metal

    Institute of Scientific and Technical Information of China (English)

    PENG Jun; WANG Shi-jun; DONG Yuan-chi; LIU Li-xia; ZHOU Yun; CHEN Er-bao

    2008-01-01

    The solubility of nitrogen in the Fe-C-V-N system was measured at 1 708 K and the model of calculating activity (action concentration) of nitroge.n (N) and vanadium (V) was derived according to the phase diagram and the coexistence theory of the metal melt structure.The solubility expression of nitrogen in the Fe-C-V-N system at 1 708 K was wN=0.058 194-0.010 367WC+0.005 543 4wV.Comparing the computing results with the experimental results,a satisfactory conclusion could be obtained.The analysis of the Fe-C-V-N system using this model showed that VN was present in a high temperature metal melt,which would reduce the action concentration of nitrogen obviously.It was consequently disadvantageous to the removal of nitrogen from hot metal.

  20. Reactive oxygen and nitrogen (ROS and RNS) species generation and cell death in tomato suspension cultures--Botrytis cinerea interaction.

    Science.gov (United States)

    Pietrowska, E; Różalska, S; Kaźmierczak, A; Nawrocka, J; Małolepsza, U

    2015-01-01

    This article reports events connected to cell survival and Botrytis cinerea infection development in cell suspension cultures of two tomato cultivars which show different levels of susceptibility to the pathogen: cv. Corindo (more susceptible) and cv. Perkoz (less susceptible). In parallel changes in reactive oxygen (ROS) and nitrogen (RNS) species generation and in S-nitrosoglutathione reductase (GSNOR) activity were studied. In vivo staining methods with acridine orange (AO) and ethidium bromide (EB) as well as fluorescent microscopy were used to assess tomato and B. cinerea cells death. The biochemical studies of ROS and RNS concentrations in plant cell extract were complemented by in vivo ROS and nitric oxide (NO) imaging using nitro blue tetrazolium (NBT), diaminobenzidine (DAB) and diaminofluorescein diacetate (DAF-DA) staining methods, and confocal microscope technique. B. cinerea infection proceeded slower in Perkoz cell cultures. It was evidenced by measuring the pathogen conidia germination and germination tube development in which nuclei revealing cell death dominated. Two different types of tomato cell death were observed: cells with necrotic nuclei dominated in Corindo whereas in Perkoz cells with characteristic of vacuolar death type prevailed. In Perkoz cells, constitutive levels of NO and S-nitrosothiols (SNO) were significantly higher and hydrogen peroxide (H₂O₂) and superoxide anion (O₂(-)) concentrations were slightly higher as compared with Corindo cells. Moreover, increases in these molecule concentrations as a result of B. cinerea inoculation were observed in both, Perkoz and Corindo cell cultures. The enzymatic GSNOR activity seems to be an important player in controlling the SNO level in tomato cells. Involvements of the studied compounds in molecular mechanisms of tomato resistance to B. cinerea are discussed in the paper. PMID:25064634

  1. The influence of nitrogen oxides on the activation of bromide and chloride in salt aerosol

    Science.gov (United States)

    Bleicher, S.; Buxmann, J. C.; Sander, R.; Riedel, T. P.; Thornton, J. A.; Platt, U.; Zetzsch, C.

    2014-04-01

    Experiments on salt aerosol with different salt contents were performed in a Teflon chamber under tropospheric light conditions with various initial contents of nitrogen oxides (NOx = NO + NO2). A strong activation of halogens was found at high NOx mixing ratios, even in samples with lower bromide contents such as road salts. The ozone depletion by reactive halogen species released from the aerosol, was found to be a function of the initial NOx mixing ratio. Besides bromine, large amounts of chlorine have been released in our smog chamber. Time profiles of the halogen species Cl2, Br2, ClNO2, BrNO2 and BrO, ClO, OClO and Cl atoms were simultaneously measured by various techniques (chemical ionization mass spectrometry, differential optical absorption spectrometry coupled with a multi-reflection cell and gas chromatography of hydrocarbon tracers for Cl and OH, employing cryogenic preconcentration and flame ionization detection). Measurements are compared to calculations by the CAABA/MECCA 0-D box model, which was adapted to the chamber conditions and took the aerosol liquid water content and composition into account. The model results agree reasonably with the observations and provide important information about the prerequisites for halogen release, such as the time profiles of the aerosol bromide and chloride contents as well as the aerosol pH.

  2. Effect of cytokinins on the activity of superoxide dismutase in nitrogen deficient wheat

    Directory of Open Access Journals (Sweden)

    Stoparić Goran Z.

    2008-01-01

    Full Text Available Reactive oxygen species (ROS, such as O2·¯, are formed by electron transfer to a molecule with stable electron configuration, in electron transport chains in the cell. ROS are very reactive molecules which are formed at higher rates under stress, such as drought, high insolation, heath, inadequate mineral nutrition, and such conditions lead to impairment of various physiological and biochemical processes in the cell. To reduce production of ROS, and their detrimental effect, plants developed various enzymatic and non-enzymatic protective mechanisms. Superoxide dismutase (SOD is one of the most important antioxydative enzymes, which removes superoxid anion radical (O2·¯, whose rate of production is the highest under unfavorable environmental conditions. Plant tissues that exhibit delayed senescence often have higher cytokinin content, which is accompanied by reduced amount of ROS. The focus of this paper is to examine whether foliar application of cytokinins to young wheat plants insufficiently supplied with nitrogen affects the activity of SOD and amount of O2·¯. Application of trans-zeatine (CK reduced the activity of SOD, but this reduction was not accompanied by an increase in the amount of O2·¯. Application of benzyl adenine (BA also reduced the activity of SOD, with concomitant increase in the amount of O2·¯ in wheat leaves.

  3. Antifungal activity of heartwood extracts from three Juniperus species

    Science.gov (United States)

    Heartwood samples from three species of Juniperus (i.e., J. virginianna, J. occidentalis, and J. ashei) were extracted with hexane, ethanol and methanol and the hexane and ethanol extracts were tested for antifungal activity against four species of wood-rot fungi. These three species represent the ...

  4. Nitrogen fixation activity in biological soil crusts dominated by cyanobacteria in the Subpolar Urals (European North-East Russia).

    Science.gov (United States)

    Patova, Elena; Sivkov, Michail; Patova, Anna

    2016-09-01

    The nitrogen fixation by biological soil crusts with a dominance of cyanobacteria was studied using the acetylene reduction assay in the territory of the Subpolar Urals (65°11' N, 60°18' E), Russia. The field measurements of nitrogen fixation activity were conducted in situ for two different types of soil crusts dominated by Stigonema (V1 type) and Nostoc with Scytonema (V2 type). The nitrogen fixation process had similar dynamics in both crusts but nitrogen fixation rates were different. The crusts of the V2 type showed a significantly higher acetylene reduction activity, with ethylene production rate of 1.76 ± 0.49 g C2H4 m(-2) h(-1) at 15°C, compared with V1-type soil crusts, with a rate of 0.53 ± 0.21 mg C2H4 m(-2) h(-1) at 15°C. The daily value of acetylene reduction activity in V2-type soil crusts was 32.7 ± 6.2 mg C2H4 m(-2) d(-1) and in V1-type crusts, 12.3 ± 1.8 mg C2H4 m(-2) d(-1) After recalculation for N, the daily values of nitrogen fixation were in the range 3.3-22.3 mg N m(-2) d(-1), which is a few times higher than the values of N input from the precipitation to the soil in the studied regions. The dependence of nitrogen-fixation activity on temperature and light intensity of biological soil crusts was investigated. On the basis of temperature models obtained from the dependence, the nitrogen balance was calculated for the growing season (approximately 120 days). The crusts dominated by Stigonema species were fixing 0.3 g N m(-2) (ethylene production rate, 1.10 g C2H4 m(-2)) and crusts dominated by Nostoc and Scytonema were fixing 1.3 g N m(-2) (4.10 g C2H4 m(-2)). PMID:27306556

  5. Field observations on nitrogen catch crops. I. Potential and actual growth and nitrogen accumulation in relation to sowing date and crop species.

    NARCIS (Netherlands)

    Vos, J.; Putten, van der P.E.L.

    1997-01-01

    In temperate climates with a precipitation surplus during autumn and winter, nitrogen catch crops can help to reduce nitrogen losses from cropping systems by absorbing nitrogen from the soil and transfer it to a following main crop. The actual and potential accumulation of dry matter and nitrogen in

  6. Carbon and Nitrogen dynamics in forest soils depending on light conditions and tree species

    Science.gov (United States)

    Veselinovic, Bojana; Hager, Herbert

    2013-04-01

    Climate change mitigation actions under the Kyoto Protocol apply among other decreases of CO2-emissions and/or increases of carbon (C) stocks. As soils represent the second biggest C-reservoir on Earth, an exact estimation of the stocks and reliable knowledge on C-dynamics in forest soils is of high importance. Anyhow, here, the accurate GHG-accounting, emission reductions and increase in C stocks is hampered due to lack of reliable data and solid statistical methods for the factors which influence C-sequestration in and its release from these systems. In spite of good progress in the scientific research, these factors are numerous and diverse in their interactions. This work focuses on influence of the economically relevant tree species - Picea abies, Fagus sylvatica and Quercus spp. - and light conditions on forest floor and mineral soil C and N dynamics in forest soils. Spruce monocultures have been widely used management practices in central European forests during the past century. Such stands are in lower altitudes and on heavy and water logged soils unstable and prone to disturbances, especially to windthrows. We hypothesize that windthrow areas loose C & N and that the establishment of the previous nutrient stocks is, if at all, only possible to be reached over the longer periods of time. We research also how the increased OM depletion affects the change of C & N stocks in forest floor vs. mineral soil. Conversion of such secondary spruce monocultures to site adequate beech and oak forests may enable higher stocks allocated predominantly as stable organic carbon and as plant available nitrogen. For this purpose sites at 300-700 m altitude with planosols were chosen in the region of the Northern Alpine Foothills. A false chronosequence approach was used in order to evaluate the impacts of the tree species and change in light conditions on dynamic of C & N in the forest floor and mineral soil, over the period 0-100 (for oak 120 y.) years. The C- and N

  7. Performance of Conventional Activated Sludge to Remove Nitrogen Compounds from Tomato Factory Wastewater

    OpenAIRE

    Meghdad Pirsaheb; Kiomars Sharafi; Golchin Rostami; Serveh Hosainie

    2012-01-01

    Today discharge of raw or treated wastewater containing nutrients (nitrogen and phosphorus compounds) to the surface water causing an Utrification phenomenon, will be due to excessive growth of algae in the receptive water source. Each of the of wastewater treatment system, providing principled design and operation can be reduced nutrients to standard level [1]. The purpose of this study was to evaluate the efficacy of conventional activated sludge systems to remove nitrogen compounds from wa...

  8. High-nitrogen and low-irradiance can restrict energy utilization in photosynthesis of successional tree species in low subtropical forest

    Institute of Scientific and Technical Information of China (English)

    CAI Xi'An; SUN GuChou; ZHAO Ping; LIU XiaoJing

    2008-01-01

    Responses of photosynthesis and the partition of energy utilization to high-nitrogen importation and high-light intensity in leaves of three dominant tree species of subtropical forest, including sun plant or early-successional species Schima superba, mesophyte or intermediate-successional species Can-stanopsis hystrix, and shading-tolerant plant or late-successional species Cryptocarya concinna were studied by using the CO2 exchange system and chlorophyll fluorescence method. Our results showed that, regardless of plant species, net photosynthetic rate (Pn) was higher in high-nitrogen supply and high irradiance (HNHL)plants than in low-nitrogen supply and high irradiance (LNHL) plants, implying that low-nitrogen importation would limit Pn of plants grown under high irradiance. However, high-nitrogen supply and low irradiance (HNLL) plants had a lower Pn. Insignificant change of quantum yield (Fv'/Fm') in opened PS II was found in leaves of HNHL, LNHL or HNLL plants of S. superba and C. hystrix, while a higher Fv'/Fm' occurred in HNHL plants of C. concinna in comparison with LNHL or HNLL plants. The HNHL plants of C. concinna also had a higher photochemical quantum yield (ARFm') than LNHL or HNLL plants, however no similar responses were found in plants of S. superba and C. hystrix (P0.05) and it was significantly higher than in HNLL plants (P<0.05). C. hystrixalso had a similar response in φPSII to nitrogen supply and irradiance. Regardless of species HNLL plants had a significant φPSII, and higher heat dissipation in light, and this effect was more severe in C. concinna than in S. superba or C. hystrix. The results may mean that high-nitrogen importation by nitrogen deposit and low irradiance caused by changing climate or air pollution would more severely restrict photo-synthetic processes in the late-successional species C. concinna than in the early-successional species S. superba and intermediate-successional species C. hystrix. The continuous high-nitrogen

  9. Evidence for Detrimental Cross Interactions between Reactive Oxygen and Nitrogen Species in Leber’s Hereditary Optic Neuropathy Cells

    Directory of Open Access Journals (Sweden)

    Micol Falabella

    2016-01-01

    Full Text Available Here we have collected evidence suggesting that chronic changes in the NO homeostasis and the rise of reactive oxygen species bioavailability can contribute to cell dysfunction in Leber’s hereditary optic neuropathy (LHON patients. We report that peripheral blood mononuclear cells (PBMCs, derived from a female LHON patient with bilateral reduced vision and carrying the pathogenic mutation 11778/ND4, display increased levels of reactive oxygen species (ROS and reactive nitrogen species (RNS, as revealed by flow cytometry, fluorometric measurements of nitrite/nitrate, and 3-nitrotyrosine immunodetection. Moreover, viability assays with the tetrazolium dye MTT showed that lymphoblasts from the same patient are more sensitive to prolonged NO exposure, leading to cell death. Taken together these findings suggest that oxidative and nitrosative stress cooperatively play an important role in driving LHON pathology when excess NO remains available over time in the cell environment.

  10. Evidence for Detrimental Cross Interactions between Reactive Oxygen and Nitrogen Species in Leber's Hereditary Optic Neuropathy Cells

    Science.gov (United States)

    Santini, Paolo

    2016-01-01

    Here we have collected evidence suggesting that chronic changes in the NO homeostasis and the rise of reactive oxygen species bioavailability can contribute to cell dysfunction in Leber's hereditary optic neuropathy (LHON) patients. We report that peripheral blood mononuclear cells (PBMCs), derived from a female LHON patient with bilateral reduced vision and carrying the pathogenic mutation 11778/ND4, display increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS), as revealed by flow cytometry, fluorometric measurements of nitrite/nitrate, and 3-nitrotyrosine immunodetection. Moreover, viability assays with the tetrazolium dye MTT showed that lymphoblasts from the same patient are more sensitive to prolonged NO exposure, leading to cell death. Taken together these findings suggest that oxidative and nitrosative stress cooperatively play an important role in driving LHON pathology when excess NO remains available over time in the cell environment. PMID:26881022

  11. Evidence for Detrimental Cross Interactions between Reactive Oxygen and Nitrogen Species in Leber's Hereditary Optic Neuropathy Cells.

    Science.gov (United States)

    Falabella, Micol; Forte, Elena; Magnifico, Maria Chiara; Santini, Paolo; Arese, Marzia; Giuffrè, Alessandro; Radić, Kristina; Chessa, Luciana; Coarelli, Giulia; Buscarinu, Maria Chiara; Mechelli, Rosella; Salvetti, Marco; Sarti, Paolo

    2016-01-01

    Here we have collected evidence suggesting that chronic changes in the NO homeostasis and the rise of reactive oxygen species bioavailability can contribute to cell dysfunction in Leber's hereditary optic neuropathy (LHON) patients. We report that peripheral blood mononuclear cells (PBMCs), derived from a female LHON patient with bilateral reduced vision and carrying the pathogenic mutation 11778/ND4, display increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS), as revealed by flow cytometry, fluorometric measurements of nitrite/nitrate, and 3-nitrotyrosine immunodetection. Moreover, viability assays with the tetrazolium dye MTT showed that lymphoblasts from the same patient are more sensitive to prolonged NO exposure, leading to cell death. Taken together these findings suggest that oxidative and nitrosative stress cooperatively play an important role in driving LHON pathology when excess NO remains available over time in the cell environment.

  12. Nitrogen Inputs via Nitrogen Fixation in Northern Plants and Soils

    Science.gov (United States)

    Thorp, N. R.; Wieder, R. K.; Vile, M. A.

    2015-12-01

    Dominated by cold and often acidic water logged environments, mineralization of organic matter is slow in the majority of northern ecosystems. Measures of extractable ammonium and nitrate are generally low and can be undetectable in peat pore waters. Despite this apparent nitrogen limitation, many of these environments produce deep deposits of soil organic matter. Biological nitrogen fixation carried out by autotrophic and heterotrophic diazotrophs associated with cryptograms provides the majority of known nitrogen inputs in these northern ecosystems. Nitrogen fixation was assessed in a variety of northern soils within rhizospheres of dominant plant communities. We investigated the availability of this newly fixed nitrogen to the vascular plant community in nitrogen limited northern plant communities. We tracked nitrogen flow from 15N2 gas fixed in Sphagnum mosses into tissues of two native vascular plant species, boreal cranberry (Vaccinium oxycoccus) and black spruce (Picea mariana). 15N-labeled Sphagnum microcosms were grown within variable mesh size exclusion/inclusion fabrics in a nitrogen addition experiment in situ in order to investigate the role of mycorrhizal fungi in the uptake of newly fixed nitrogen. Up to 24% of daily fixed 15N label was transferred to vascular plant tissues during 2 months. Nitrogen addition resulted in decreased N2 fixation rates; however, with higher nitrogen availability there was a higher rate of 15N label uptake into the vascular plants, likely the result of increased production of dissolved organic nitrogen. Reliance on mycorrhizal networks for nitrogen acquisition was indicated by nitrogen isotope fractionation patterns. Moreover, N2 fixation activities in mosses were stimulated when vascular plants were grown in moss microcosms versus "moss only" treatments. Results indicate that bog vascular plants may derive considerable nitrogen from atmospheric N2 biologically fixed within Sphagnum mosses. This work demonstrates that

  13. The QQS orphan gene regulates carbon and nitrogen partitioning across species via NF-YC interactions

    Science.gov (United States)

    The allocation of carbon and nitrogen resources to the synthesis of plant proteins, carbohydrates, and lipids is complex and under the control of many genes; much remains to be understood about this process. QQS (Qua Quine Starch, At3g30720), an orphan gene unique to Arabidopsis thaliana, regulates...

  14. Interactive effects of ocean acidification and nitrogen limitation on two bloom-forming dinoflagellate species

    NARCIS (Netherlands)

    Eberlein, T.; Van de Waal, D.B.; Brandenburg, Karen M.; John, U.; Voss, M.; Achterberg, E.P.; Rost, B.

    2016-01-01

    Global climate change involves an increase in oceanic CO2 concentrations as well as thermal stratification of the water column, thereby reducing nutrient supply from deep to surface waters. Changes in inorganic carbon (C) or nitrogen (N) availability have been shown to affect marine primary producti

  15. Prone to fix: Resilience of the active nitrogen-fixing rice root microbiome

    Science.gov (United States)

    Hurek, Thomas; Sabale, Mugdha; Sarkar, Abhijit; Pees, Tobias; Reinhold-Hurek, Barbara

    2016-04-01

    Due to water consumption, many lowland rice areas in Asia are undergoing a transition that involves adoption of new management strategies, with crop rotations encompassing a non-flooded crop, including maize. Shifting from flooded to non-flooded cropping is likely to affect microbial nitrogen cycling. For analysis of the root-associated microbiome of rice and maize in response to flooding or nitrogen fertilizer, we combine methods of microbial ecology (Next-Generation sequencing of amplicons), and a reductionist approach with pure cultures of the endophytic diazotroph Azoarus sp.. Field plots of the ICON project (Introducing non-flooded crops in rice-dominated landscapes: Impact on Carbon, nitrogen and water budgets) at the International Rice Research Institute in the Philippines were analyzed. Root-associated activity of nitrogenase gene expression was assessed by quantitative RT-PCR of nifH. For rice, expression levels were surprisingly stable, in response to non-flooded versus flooded conditions, or in response to conventional nitrogen fertilizer applications versus lack of N-fertilizer. In contrast, the active diazotrophic population of maize roots was not resistant to N-fertilization, nifH expression strongly decreased. Concordant changes in the diazotrophic resident or active communities were detected by nifH amplicon sequence analysis, based on bacterial DNA or mRNA, respectively. For high-resolution analyses of the endobiome in gnotobiotic culture, we developed a dual fluorescence reporter system for Azoarcus sp. BH72 which allows to quantify and visualize epi- and endophytic gene expression by concfocal microscopy (CLSM). This allowed us to demonstrate sites of active nitrogen fixation (gene expression) in association with rice roots. We confirmed that at low nitrogen fertilizer levels, endophytic nifH gene expression persisted in rice roots, while it was repressed in maize roots. This supports our observation of remarkable stability of nitrogen fixation

  16. Determination of oxygen, carbon and nitrogen in calcium by the gamma activation method

    International Nuclear Information System (INIS)

    Gamma-activation determination of oxygen, carbon and nitrogen in technical calcium is described. The method involves (γ,n) reactions of 16O, 12C and 14N. To determine the concentration of the admixtures the activities of 15O, 11C and 13N have been compared with those of the reference samples (LAVSAN polyester, boron nitride and aluminium nitride). Upon irradiation the calcium samples have undergone surface cleaning by 20-30 sec. etching in concentrated hydrochloric acid. Because of the matrix activation and the presence of other admixtures the determination of oxygen, carbon and nitrogen requires their radiochemical isolation. The average concentrations of oxygen, carbon and nitrogen in six calcium samples have been 3x10sup(-1), 3x10sup(-3) and 7x10sup(-3) % wt

  17. Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates in northwestern Turkey

    OpenAIRE

    Sariyildiz T; Savaci G; Kravkaz IS

    2016-01-01

    Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates were investigated in the northwest of Turkey using 4 common tree species as black pine (Pinus nigra Arnold.), Scots pine (Pinus sylvestris L.), Oriental beech (Fagus orientalis Lipsky) and Uludag fir (Abies nordmanniana ssp. bornmuelleriana). Three tree species (black pine, Scots pine and Oriental beech) were used to investigate the differences in soil C and N among tree species. Old and young Uluda...

  18. The import and export of organic nitrogen species at a Scottish ombrotrophic peatland

    Science.gov (United States)

    McKenzie, R. M.; Özel, M. Z.; Cape, J. N.; Drewer, J.; Dinsmore, K. J.; Nemitz, E.; Hamilton, J. F.; Sutton, M. A.; Gallagher, M. W.; Skiba, U.

    2015-01-01

    Dissolved organic nitrogen (DON) can contribute significantly to the overall nitrogen budget, but is not routinely measured in precipitation or stream water. In order to investigate the contribution of DON to deposition and export of N, precipitation, stream and soil water samples were collected from an ombrotrophic peatland and analysed for DON Over a two year period. In wet only deposition DON contributed up to 10% of the total dissolved nitrogen (TDN), 99% in soil water, and 75% in stream water. No correlations were observed between DIN and DON in precipitation stream water or soil water. DIN is an important source of nutrients and in ombrotrophic peatlands, is only deposited via precipitation. Too much nitrogen to a sensitive ecosystem can result in problems with the way in which it is processed, such as an increase in the export of N via nearby water bodies. It is therefore important to monitor N deposition and export. Precipitation DIN showed a loose seasonal pattern, with peak concentrations occurring between January and June, while DON concentrations tended to be lower in the winter months. Stream water DON and NH4+ showed no obvious seasonal pattern but NO3- showed larger concentrations in cooler months and the smallest during warmer months, with the exception of June and July 2010, when concentrations were high. Precipitation and stream DON was qualitatively analysed using GC × GC-NCD. Ten unique compounds were detected, of which only five could be identified: pyrrole, benzonitrile, dodecylamine, N-nitrosodipropylamine and decylamine. Five compounds were present in both precipitation and stream samples: pyrrole, benzonitrile and three unidentified compounds. A more detailed DON speciation may be used to identify sources and pathways of DON.

  19. The import and export of organic nitrogen species at a Scottish ombrotrophic peatland

    Directory of Open Access Journals (Sweden)

    R. M. McKenzie

    2015-01-01

    Full Text Available Dissolved organic nitrogen (DON can contribute significantly to the overall nitrogen budget, but is not routinely measured in precipitation or stream water. In order to investigate the contribution of DON to deposition and export of N, precipitation, stream and soil water samples were collected from an ombrotrophic peatland and analysed for DON Over a two year period. In wet only deposition DON contributed up to 10% of the total dissolved nitrogen (TDN, 99% in soil water, and 75% in stream water. No correlations were observed between DIN and DON in precipitation stream water or soil water. DIN is an important source of nutrients and in ombrotrophic peatlands, is only deposited via precipitation. Too much nitrogen to a sensitive ecosystem can result in problems with the way in which it is processed, such as an increase in the export of N via nearby water bodies. It is therefore important to monitor N deposition and export. Precipitation DIN showed a loose seasonal pattern, with peak concentrations occurring between January and June, while DON concentrations tended to be lower in the winter months. Stream water DON and NH4+ showed no obvious seasonal pattern but NO3- showed larger concentrations in cooler months and the smallest during warmer months, with the exception of June and July 2010, when concentrations were high. Precipitation and stream DON was qualitatively analysed using GC × GC-NCD. Ten unique compounds were detected, of which only five could be identified: pyrrole, benzonitrile, dodecylamine, N-nitrosodipropylamine and decylamine. Five compounds were present in both precipitation and stream samples: pyrrole, benzonitrile and three unidentified compounds. A more detailed DON speciation may be used to identify sources and pathways of DON.

  20. Aeration control by monitoring the microbiological activity using fuzzy logic diagnosis and control. Application to a complete autotrophic nitrogen removal reactor

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo; Mauricio Iglesias, Miguel; Vangsgaard, Anna Katrine;

    2015-01-01

    . This contribution describes the development of a fuzzy-logic based system for both diagnosis and control of a CANR reactor. Based on a combination of measurements of the nitrogen species concentration in the influent and in the effluent on the one hand, and insights into the activities of three distinctive...... to the reactor.The diagnosis tool was first evaluated using 100 days of real process operation data obtained from a lab-scale single-stage autotrophic nitrogen removing reactor. This evaluation revealed that the fuzzy logic diagnosis is able to provide a realistic description of the microbiological state...

  1. Diversity and activity of Lysobacter species from disease suppressive soils

    NARCIS (Netherlands)

    Gómez Expósito, Ruth; Postma, Joeke; Raaijmakers, Jos M; de Bruijn, Irene

    2015-01-01

    BACKGROUND: The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoct

  2. Diversity and Activity of Lysobacter Species from Disease Suppressive Soils

    NARCIS (Netherlands)

    Gomez Exposito, R.; Postma, J.; Raaijmakers, J.M.; Bruijn, de I.

    2015-01-01

    The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes, and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoctonia solani

  3. Facile synthesis, characterization and antimicrobial activities of diphenylphosphoryl derivatives of substituted aryl and nitrogen heterocycles

    Directory of Open Access Journals (Sweden)

    G. Subba Reddy

    2013-03-01

    Full Text Available Diphenylphosphoryl derivatives of substituted aryl and nitrogen heterocycles were prepared by a one-pot process involving sequential reaction of diphenylphosphine chloride with dry methyl alcohol/ethyl alcohol and then with different halides of substituted nitrogen heterocycles/aryl halides. The title compounds (5a-j structures were established by analytical, IR, NMR ( 1H, 13C and 31P and mass spectra, and they have been screened for their antimicrobial activity. They exhibited significant antibacterial and antifungal activity.

  4. Influence of nitrogen supply on spring barley productivity and nitrate reductase activity

    Directory of Open Access Journals (Sweden)

    U. Wojcieska

    2013-12-01

    Full Text Available The aim of the present study was to obtain some informations on the productivity of four chosen barley varieties growing at low and high nitrogen level. Some parameters of the yield structure and nitrate reductase activity were taken into consideration. It was found that there exist some differences in the yield between the compared varieties and some differences in their reaction to a high N level in the soil. The grain yield increase of the plants treated with high nitrogen doses was above all the result of the increase in dry matter of the lateral shoots and in leaf area. Distinct increase in the number of grains per ear and 1000-grains weight was also observed. The amount of reduced nitrogen collected during the growth season depended, in part, on the nitrate reductase activity and in part on the amount of the enzyme present in the plant. A rise of the nitrogen level caused an increase in nitrate reductase activity, in all varieties. The different influence of nitrogen on the growth of green organs in the compared varieties caused differences in the amount of the enzyme present in the plants and in protein yields.

  5. Enhanced photoelectric property and visible activity of nitrogen doped TiO2 synthesized from different nitrogen dopants

    Science.gov (United States)

    Cheng, Xiuwen; Yu, Xiujuan; Xing, Zipeng

    2013-03-01

    N doped TiO2 nano-particles were synthesized through simple sol-gel reactions from different nitrogen dopants. The resulting materials were characterized by X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) and surface photovoltage spectroscopy (SPS). Furthermore, the photoelectric property and activity enhanced mechanism were investigated in detail. It was found that the introduction of N dopants could effectively inhibit the crystal growth of TiO2 nano-particles, enhance the light absorption in visible region, possess more surface hydroxyl groups and separate the photoinduced charge carriers. The effects of dopants on the photocatalytic activity for the degradation of rhodamine B (RhB) were investigated in detail. It is clearly demonstrated that the photocatalytic activity of N)-TiO nano-particle was higher than that of NCl)-TiO and undoped TiO2. The enhanced photocatalytic activity could be attributed to the smaller crystal size, more hydroxyl groups on surface of the catalyst, stronger light absorption in visible region and higher separation efficiency of photoinduced charge carriers.

  6. Nitrogen control of 13C enrichment in heterotrophic organs relative to leaves in a landscape-building desert plant species

    Science.gov (United States)

    Zhang, J.; Gu, L.; Bao, F.; Cao, Y.; Hao, Y.; He, J.; Li, J.; Li, Y.; Ren, Y.; Wang, F.; Wu, R.; Yao, B.; Zhao, Y.; Lin, G.; Wu, B.; Lu, Q.; Meng, P.

    2015-01-01

    A longstanding puzzle in isotope studies of C3 plant species is that heterotrophic plant organs (e.g., stems, roots, seeds, and fruits) tend to be enriched in 13C compared to the autotrophic organ (leaves) that provides them with photosynthate. Our inability to explain this puzzle suggests key deficiencies in understanding post-photosynthetic metabolic processes. It also limits the effectiveness of applications of stable carbon isotope analyses in a variety of scientific disciplines ranging from plant physiology to global carbon cycle studies. To gain insight into this puzzle, we excavated whole plant architectures of Nitraria tangutorum Bobrov, a C3 species that has an exceptional capability of fixing sands and building sand dunes, in two deserts in northwestern China. We systematically and simultaneously measured carbon isotope ratios and nitrogen and phosphorous contents of different parts of the excavated plants. We also determined the seasonal variations in leaf carbon isotope ratios on nearby intact plants of N. tangutorum. We found, for the first time, that higher nitrogen contents in heterotrophic organs were significantly correlated with increased heterotrophic 13C enrichment compared to leaves. However, phosphorous contents had no effect on the enrichment. In addition, new leaves had carbon isotope ratios similar to roots but were progressively depleted in 13C as they matured. We concluded that a nitrogen-mediated process, hypothesized to be the refixation of respiratory CO2 by phosphoenolpyruvate (PEP) carboxylase, was responsible for the differences in 13C enrichment among different heterotrophic organs, while processes such as fractionating foliar metabolism and preferentially loading into phloem of 13C-enriched sugars may contribute to the overall autotrophic-heterotrophic difference in carbon isotope compositions.

  7. Helicon Discharge with Selectable Nitrogen Reactive Species Production as a Plasma Source for III-group Nitrides Growth by MBE

    Science.gov (United States)

    Biloiu, Costel; Doss, Forest; Scime, Earl

    2004-11-01

    Plasma assisted molecular beam epitaxy (PAMBE) of III-N materials is a potential alternative to MOCVD for fabrication of high quality wide band gap semiconductor devices. In the helicon plasma source, it may be possible to control the population of specific reactive nitrogen species by modification of the electron energy distribution function through the resonant wave-particle interaction arising from electrons traveling at same velocity as the helicon wave phase velocity. We report preliminary results on control of reactive nitrogen species performed in a steady state, high density, helicon plasma source CHEWIE (Compact HElicon Waves and Instabilities Experiment). The helicon vacuum chamber is a 12 cm long, Pyrex tube, 6 cm in diameter, connected to a stainless steel diffusion chamber. RF power of up to 1.0 kW over a frequency range of 3-28 MHz is used to create the steady state plasma. A 7 cm long, half wave, m = +1, helical antenna couples the rf energy into the plasma. A single solenoidal magnetic field coil surrounds the source and is capable of generating axial magnetic fields up to 600 G. Optical emission spectroscopy investigations show that under certain conditions, the decay from the long lived A^3Σ_u^+ state dominates the emission spectrum of the plasma.

  8. Lanthanide ions (III) as sensitizers of melatonin oxidation in reaction mixtures providing reactive species of oxygen and nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Kaczmarek, Małgorzata, E-mail: mkaczmar@amu.edu.pl

    2015-06-15

    Chemiluminescence (CL) of the reactive systems providing strong oxidants (reactive species of oxygen and nitrogen) containing lanthanide ions (III) and melatonin, was studied. Kinetic curves of emission decay and spectral distributions of chemiluminescence were obtained. Analysis of differences in the intensity of chemiluminescence and CL spectra proved that excitation of Tb(III) and Dy(III) ions takes place with the energy transfer from the products of melatonin oxidation: N{sup 1}-acetyl-N{sup 2}-formyl-5-methoxykynuramine (AFMK) and N{sup 1}-acetyl-5-methoxykynuramine (AMK) to the lanthanide ions. In the system Fe(II)/Fe(III)–H{sub 2}O{sub 2}–Mel–Tb(III) a linear correlation was established between the integrated CL intensity and melatonin concent. - Highlights: • Chemiluminescence (CL) of melatonin (Mel) oxidation by reactive species of oxygen and nitrogen. • Tb(III) and Dy(III) ions as sensitizers of a melatonin oxidation process. • New CL method for determination of melatonin in pharmaceutical preparations based on CL of Fe(II)/Fe(III)–H{sub 2}O{sub 2}–Mel–Tb(III) system.

  9. Comparative study of hemolytic activity of Bordetella species

    Directory of Open Access Journals (Sweden)

    C N Khobragade

    2009-11-01

    Full Text Available Background and objectives: Bordetella species colonize the respiratory tract of mammals and thereby cause the whooping cough. Most of the species produce adenylate cyclase - a toxin ( hemolysin responsible for increasing intracellular cyclic AMP (cAMP levels in mammalian neutrophils and macrophages and as a consequence their phagocytic function get impaired . This study was carried out to isolate species of Bordetella and to study the hemolytic activity of each species on RBCs of sheep, human and poultry at varied culture conditions by altering the temperature, pH and cell age."nMaterials and Methods: Three pathogenic Bordetella species were isolated from fifty suspected whooping cough patients on Bordet-Gengou agar and identified by their biochemical profiles. The hemolytic activity of B. pertussis, B. parapertussis and B. bronchiseptica was investigated in terms of cell bound and cell free hemolysin on human, poultry and sheep RBCs at variable pH, temperature and cell age in Stainer Scholt broth. The hemolysin activity was also determined qualitatively on blood agar containing different blood samples."nResults: All the species revealed optimum hemolytic activity in pH range 7.5-8.0 (in slight alkaline condition, temperature 37°C and cell age up to 20-24 hrs. The cell bound hemolytic activity was found to be maximum than cell free activity and varied with blood samples of different species. B. pertussis showed maximum hemolytic activity on human red blood cells followed by poultry and sheep RBCs. B. parapertussis and B. bronchiseptica showed maximum hemolytic activity on sheep and poultry RBCs respectively."nConclusion: The findings of our study revealed that different determinants are involved in host interactions and virulence of Bordetella species.

  10. Carbon and nitrogen limitation increase chitosan antifungal activity in Neurospora crassa and fungal human pathogens

    OpenAIRE

    Lopez-Moya, Federico; Colom-Valiente, Maria F.; Martínez Peinado, Pascual; Martinez-Lopez, Jesus E.; Puelles, Eduardo; Sempere Ortells, José Miguel; López Llorca, Luis Vicente

    2015-01-01

    Chitosan permeabilizes plasma membrane and kills sensitive filamentous fungi and yeast. Membrane fluidity and cell energy determine chitosan sensitivity in fungi. A five-fold reduction of both glucose (main carbon (C) source) and nitrogen (N) increased 2-fold Neurospora crassa sensitivity to chitosan. We linked this increase with production of intracellular reactive oxygen species (ROS) and plasma membrane permeabilization. Releasing N. crassa from nutrient limitation reduced chitosan antifun...

  11. Revealing the Origin of Activity in Nitrogen-Doped Nanocarbons towards Electrocatalytic Reduction of Carbon Dioxide

    DEFF Research Database (Denmark)

    Xu, Junyuan; Kan, Yuhe; Huang, Rui;

    2016-01-01

    Carbon nanotubes (CNTs) are functionalized with nitrogen atoms for reduction of carbon dioxide (CO2). The investigation explores the origin of the catalyst’s activity and the role of nitrogen chemical states therein. The catalysts show excellent performances, with about 90% current efficiency...... for CO formation and stability over 60 hours. The Tafel analyses and density functional theory calculations suggest that the reduction of CO2 proceeds through an initial rate-determining transfer of one electron to CO2, which leads to the formation of carbon dioxide radical anion (CO2C). The initial...... reduction barrier is too high on pristine CNTs, resulting in a very high overpotentials at which the hydrogen evolution reaction dominates over CO2 reduction.The doped nitrogen atoms stabilize the radical anion,thereby lowering the initial reduction barrier and improving the intrinsic activity. The most...

  12. Comparison of Nitrogen Fertilizers, Induce and Zinc Addition on Glyphosate Efficacy on Three Different Weed Species.

    OpenAIRE

    Hussein F. Abouziena; Ibraheem M. El-Metwally; H.M. El-Saeid; Megh Singh

    2014-01-01

    Herbicides are often tank-mixed with fertilizers to save time, labour, energy, and equipment costs. However addition of some additives with glyphosate may result in reducing glyphosate efficacy. Therefore we evaluated the potential of three nitrogen sources (ammonium sulphate (AMS) at 2 or 4% w/v, ammonium nitrate (AN) at 1 or 2% w/v, urea at 1 or 2 % w/v), nonionic adjuvant (Induce at 0.05% v/v) and Zn at 250 g Zn/ha (1321 ppm) to enhance glyphosate efficacy on pig weed (Amaranthus retroflex...

  13. Quantitative trait locus analysis of symbiotic nitrogen fixation activity in the model legume Lotus japonicus.

    Science.gov (United States)

    Tominaga, Akiyoshi; Gondo, Takahiro; Akashi, Ryo; Zheng, Shao-Hui; Arima, Susumu; Suzuki, Akihiro

    2012-05-01

    Many legumes form nitrogen-fixing root nodules. An elevation of nitrogen fixation in such legumes would have significant implications for plant growth and biomass production in agriculture. To identify the genetic basis for the regulation of nitrogen fixation, quantitative trait locus (QTL) analysis was conducted with recombinant inbred lines derived from the cross Miyakojima MG-20 × Gifu B-129 in the model legume Lotus japonicus. This population was inoculated with Mesorhizobium loti MAFF303099 and grown for 14 days in pods containing vermiculite. Phenotypic data were collected for acetylene reduction activity (ARA) per plant (ARA/P), ARA per nodule weight (ARA/NW), ARA per nodule number (ARA/NN), NN per plant, NW per plant, stem length (SL), SL without inoculation (SLbac-), shoot dry weight without inoculation (SWbac-), root length without inoculation (RLbac-), and root dry weight (RWbac-), and finally 34 QTLs were identified. ARA/P, ARA/NN, NW, and SL showed strong correlations and QTL co-localization, suggesting that several plant characteristics important for symbiotic nitrogen fixation are controlled by the same locus. QTLs for ARA/P, ARA/NN, NW, and SL, co-localized around marker TM0832 on chromosome 4, were also co-localized with previously reported QTLs for seed mass. This is the first report of QTL analysis for symbiotic nitrogen fixation activity traits.

  14. Foliar stable carbon and nitrogen isotopes in woody Mediterranean species with different life form and post-fire regeneration.

    Science.gov (United States)

    Saura-Mas, S; Lloret, F

    2010-01-01

    Wildfire is an important ecological disturbance factor in most Mediterranean ecosystems. In the Mediterranean Basin, most shrub species can regenerate after fire by resprouting or seeding. Here, we hypothesize that post-fire regenerative syndromes may potentially co-vary with traits directly related to functional properties involved in resource use. Thus, seeders with a shorter life span and smaller size would have lower water-use efficiency (WUE) than re-sprouting species and would take up nutrients such as nitrogen from more superficial parts of the soil. To test this hypothesis, we compared leaf (13)C and (15)N signatures from 29 co-existing species with different post-fire regeneration strategies. We also considered life form as an additional explanatory variable of the differences between post-fire regenerative groups. Our data support the hypothesis that seeder species (which mostly evolved in the Quaternary under a Mediterranean climate) have lower WUE and less stomatal control than non-seeders (many of which evolved under different climatic conditions in the Tertiary) and consequently greater consumption of water per unit biomass. This would be related to their smaller life forms, which tend to have lower WUE and shorter life and leaf lifespan. Differences in (15)N also support the hypothesis that resprouters have deeper root systems than non-resprouters. The study supports the hypothesis of an overlap between plant functional traits and plant attributes describing post-disturbance resilience. PMID:20653895

  15. Developing Sidedress Nitrogen Recommendations for Corn using an Active Sensor

    Science.gov (United States)

    Active crop canopy reflectance sensors can be used during a sidedress N application to modify on-the-go fertilizer rates; but will this method be an improvement to current approaches to developing N recommendations? Our objective was to compare the potential for developing N recommendations for corn...

  16. Carbon and Nitrogen Sources Influence Tricalcium Phosphate Solubilization and Extracellular Phosphatase Activity by Talaromyces flavus.

    Science.gov (United States)

    Stefanoni Rubio, P J; Godoy, M S; Della Mónica, I F; Pettinari, M J; Godeas, A M; Scervino, J M

    2016-01-01

    The aim of this work was to study phosphate (P) solubilization (and the processes involved in this event) by Talaromyces flavus (BAFC 3125) as a function of carbon and/or nitrogen sources. P solubilization was evaluated in NBRIP media supplemented with different carbon (glucose, sorbitol, sucrose, and fructose) and nitrogen (L-asparagine, urea, ammonium sulfate (AS), and ammonium nitrate (AN) combinations. The highest P solubilization was related to the highest organic acid production (especially gluconic acid) and pH drop for those treatments where glucose was present. Also P solubilization was higher when an inorganic nitrogen source was supplemented to the media when compared to an organic one. Although not being present an organic P source, phosphatase activity was observed. This shows that P mineralization and P solubilization can occur simultaneously, and that P mineralization is not induced by the enzyme substrate. The combination that showed highest P solubilization was for AN-glucose. The highest acid phosphatase activity was for AS-fructose, while for alkaline phosphatase were for AS-fructose and AN-fructose. Acid phosphatase activity was higher than alkaline. P solubilization and phosphatase activity (acid and alkaline) were influenced by the different carbon-nitrogen combinations. A better understanding of phosphate-solubilizing fungi could bring a better use of soil P.

  17. Nitrogen mustard derivated from adiphenine. Synthesis and 14C labelling. Antitumor activity and tissular distribution

    International Nuclear Information System (INIS)

    The synthesis of a new nitrogen mustard 14C is described. The compound is found to be active in intraperitoneal murine L 1210 and P 388 tumors. Preliminary tissue distribution studies after i.v. administration to rats and mice show that the mustard and/or its metabolites partially cross the blood-brain barrier

  18. Role of ureolytic activity in Bacillus cereus nitrogen metabolism and acid survival

    NARCIS (Netherlands)

    Mols, J.M.; Abee, T.

    2008-01-01

    The presence and activities of urease genes were investigated in 49 clinical, food, and environmental Bacillus cereus isolates. Ten strains were shown to have urease genes, with eight of these strains showing growth on urea as the sole nitrogen source. Two of the urease-positive strains, including t

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

    Science.gov (United States)

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

    2016-01-15

    To determine the dominant nitrogen sources and select effective macroalgal species for monitoring eutrophication along the Yantai coast, the total carbon (TOC), total nitrogen (TN) and nitrogen stable isotope ratio (δ(15)N) in macroalgal tissue were analyzed in conjunction with environmental variables in seawater along the Yantai coastline. The ranges of macroalgal tissue δ(15)N values together with dissolved inorganic nitrogen (DIN) composition indicated that except for the atmospheric deposition, there were three dominant types of nitrogen sources along the Yantai coast, with the agricultural fertilizer usage and factorial wastewater input at the S1 (Zhifu Island coast), the sewage discharge at S2 (the Moon Bay coast), the sewage discharge together with aquaculture impacts at S3 (Fisherman Wharf coast) and S4 (the Horse Island coast). Macroalgal growth were not limited by DIN but limited by P at S2, S3 and S4. Macroalgal species suitable or not for DIN source tracing along the Yantai coast were discussed. For sites with low DIN concentration, many species of three phyla could be used for DIN sources tracing with Laurencia okamurai, Gloiopeltis furcata and Ulva pertusa being ideal species. For site with high DIN concentration, however, species of Rhodophyta were not suitable and only Scytosiphon lomentaria and Monostroma nitidium were chosen. PMID:26519590

  20. ANTIPYRETIC ACTIVITIES OF SOME SPECIES OF ANDROGRAPHIS WALL

    OpenAIRE

    Balu, S.; Boopathi, C. Alagesa; Elango, V.

    1993-01-01

    The antipyretic activities of the alcoholic extracts of three species of Andrographis Wall, were assayed at a dose of 500 mg/kg body weight in pyrogenic polysaccharide – induced hyperpyrexia in male albino rats. All the extracts were found to be effective in the inhibition of pyrexia. The maximal antipyretic activity was found with the alcoholic extract of Andrographis alata Nees.

  1. Cross-Species Hybridization with Fusarium verticillioides Microarrays Reveals New Insights into Fusarium fujikuroi Nitrogen Regulation and the Role of AreA and NMR

    Science.gov (United States)

    In filamentous fungi, the GATA-type transcription factor AreA plays a major role in transcriptional activation of genes needed to utilize poor nitrogen sources. Previously we have shown that in Fusarium fujikuroi AreA also controls genes involved in biosynthesis of nitrogen-free secondary metabolit...

  2. Active transposable elements recover species boundaries and geographic structure in Madagascan coffee species.

    Science.gov (United States)

    Roncal, Julissa; Guyot, Romain; Hamon, Perla; Crouzillat, Dominique; Rigoreau, Michel; Konan, Olivier N'Guessan; Rakotomalala, Jean-Jacques; Nowak, Michael D; Davis, Aaron P; de Kochko, Alexandre

    2016-02-01

    The completion of the genome assembly for the economically important coffee plant Coffea canephora (Rubiaceae) has allowed the use of bioinformatic tools to identify and characterize a diverse array of transposable elements (TEs), which can be used in evolutionary studies of the genus. An overview of the copy number and location within the C. canephora genome of four TEs is presented. These are tested for their use as molecular markers to unravel the evolutionary history of the Millotii Complex, a group of six wild coffee (Coffea) species native to Madagascar. Two TEs from the Gypsy superfamily successfully recovered some species boundaries and geographic structure among samples, whereas a TE from the Copia superfamily did not. Notably, species occurring in evergreen moist forests of eastern and southeastern Madagascar were divergent with respect to species in other habitats and regions. Our results suggest that the peak of transpositional activity of the Gypsy and Copia TEs occurred, respectively, before and after the speciation events of the tested Madagascan species. We conclude that the utilization of active TEs has considerable potential to unravel the evolutionary history and delimitation of closely related Coffea species. However, the selection of TE needs to be experimentally tested, since each element has its own evolutionary history. Different TEs with similar copy number in a given species can render different dendrograms; thus copy number is not a good selection criterion to attain phylogenetic resolution. PMID:26231981

  3. Changes in Nitrogen Metabolism and Antioxidant Enzyme Activities of Maize Tassel in Black Soils Region of Northeast China

    Directory of Open Access Journals (Sweden)

    Hongwen eXu

    2014-10-01

    Full Text Available Two varieties of maize (Zea mays L. grown in fields in Black soils of Northeast China were tested to study the dynamic changes of nitrogen metabolism and antioxidant enzyme activity in tassels of maize. Results showed that antioxidant enzyme activity in tassels of maize increased first and then decreased with the growing of maize, and reached peak value at shedding period. Pattern of proline was consistent with antioxidant enzyme activity, showing that osmotic adjustment could protect many enzymes, which are important for cell metabolism. Continuous reduction of soluble protein content along with the growing of maize was observed in the study, which indicated that quantitative material and energy were provided for pollen formation. Besides, another major cause was that a large proportion of nitrogen was used for the composition of structural protein. Nitrate nitrogen concentrations of tassels were more variable than ammonium nitrogen, which showed that nitrate nitrogen was the favored nitrogen source for maize.

  4. Growth response of four freshwater algal species to dissolved organic nitrogen of different concentration and complexity

    DEFF Research Database (Denmark)

    Fiedler, Dorothea; Graeber, Daniel; Badrian, Maria;

    2015-01-01

    is within the range of concentrations that have been observed in a typical Central European shallow, eutrophic lake. 3. All studied species grew in all treatments, but their biomass gains decreased with increasing complexity of the N source. Urea addition caused the strongest biomass increase, only in some...... concentrations. The importance of complex DON compounds for growth of common phytoplankton species is still unknown. 2. This study compared changes in chlorophyll a concentrations of freshwater phytoplankton with different DON compounds of varying complexity (urea, dissolved free (DFAA) and combined amino acids...... cases matched by nitrate. 4. Urea was also utilised over a longer time period than any other compound, including nitrate. The assumed delay in availability with increasing compound complexity was not supported by this experiment. 5. The studied species differed in their temporal response...

  5. Modelling the impact of climatic conditions and plant species on the nitrogen release from mulch of legumes at the soil surface

    Science.gov (United States)

    Gaudinat, Germain; Lorin, Mathieu; Valantin-morison, Muriel; Garnier, Patricia

    2015-04-01

    Cover crops provide multiple services to the agro ecosystem. Among them, the use of legumes as cover crop is one of the solutions for limiting the use of herbicides, mineral fertilizers, and insecticides. However, the dynamic of mineralization is difficult to understand because of the difficulty of measuring nitrogen release from mulch in field. Indeed, residues are degraded at the soil surface as mulch, while the nitrogen uptake by the main crop occurred simultaneously in the soil. This work aims to study the dynamics of nitrogen mineralization from legume residues through i) the use of a model able to describe the physical and biological dynamic of mulch and ii) a data set from a field experiment of intercropping systems "oilseed rape-legumes" from different species (grass pea, lentil, Berseem clover, field pea, vetch). The objective of the simulations is to identify the variations of expected quantities of nitrogen from different legumes. The soil-plant model of mulch decomposition PASTIS-Mulch was used to determine the nitrogen supply from mulch available for rapeseed. These simulation results were compared to the data collected in the experimental field of Grignon (France). We performed analyzes of biochemical and physical characteristics of legume residues and monitored the evolution of mulches (moisture, density, cover surface, biomass) in fields. PASTIS simulations of soil temperature, soil moisture, mulch humidity and mulch decomposition were close to the experimental results. The PASTIS model was suitable to simulate the dynamic of legume mulches in the case of "rape - legume" associations. The model simulated nitrogen restitution of aerial and root parts. We found a more rapid nitrogen release by grass pea than other species. Vetch released less nitrogen than the other species. The scenarios for climate conditions were : i) a freezing in December that causes the destruction of plants, or a destruction by herbicide in March, ii) a strong or a weak rainy

  6. Effect of powdered activated carbon technology on short-cut nitrogen removal for coal gasification wastewater.

    Science.gov (United States)

    Zhao, Qian; Han, Hongjun; Xu, Chunyan; Zhuang, Haifeng; Fang, Fang; Zhang, Linghan

    2013-08-01

    A combined process consisting of a powdered activated carbon technology (PACT) and short-cut biological nitrogen removal reactor (SBNR) was developed to enhance the removal efficiency of the total nitrogen (TN) from the effluent of an upflow anaerobic sludge bed (UASB) reactor, which was used to treat coal gasification wastewater (CGW). The SBNR performance was improved with the increasing of COD and TP removal efficiency via PACT. The average removal efficiencies of COD and TP in PACT were respectively 85.80% and 90.30%. Meanwhile, the NH3-N to NO2-N conversion rate was achieved 86.89% in SBNR and the total nitrogen (TN) removal efficiency was 75.54%. In contrast, the AOB in SBNR was significantly inhibited without PACT or with poor performance of PACT in advance, which rendered the removal of TN. Furthermore, PAC was demonstrated to remove some refractory compounds, which therefore improved the biodegradability of the coal gasification wastewater. PMID:23735800

  7. Protein intake and nitrogen balance in male non-active adolescents and soccer players.

    Science.gov (United States)

    Boisseau, N; Le Creff, C; Loyens, M; Poortmans, J R

    2002-12-01

    Recommendations for the requirements for protein intake amount usually to 0.8-1.0 g x kg(-1) body mass x day(-1) in adolescents without any reference to the undertaking of acute exercise or to the training status. The present investigation intended to determine the nitrogen balance and protein intake in 8 healthy male non-active adolescents and 11 adolescent soccer players, both groups aged about 15 years. An assessment of nutrient intake was obtained by analysing 7 day food records collected by a questionnaire. Nitrogen excretion rate was determined and nitrogen balance was calculated from the mean daily protein intake and the urinary excretion. The results showed that the nutritional status of the two groups was similar. Nevertheless, we found that their diets were quite inappropriate in terms of the intakes of carbohydrate, some minerals (zinc, calcium, magnesium), vitamins (A, B6, D) and fibre. A positive nitrogen balance was observed from a mean protein intake of 1.57 g x kg(-1) body mass x day(-1) in these adolescents, whether they were non-active or athletes. Thus, the present investigation indicated that the growth and development in non-active adolescents and in adolescent soccer-players give rise to a need for a higher protein intake than is usually recommended. However, the higher protein requirements did not seem to be related only to the increased energy expenditure imposed by the exercise training in the soccer-player group.

  8. Highly active oxygen reduction non-platinum group metal electrocatalyst without direct metal-nitrogen coordination

    Science.gov (United States)

    Strickland, Kara; Miner, Elise; Jia, Qingying; Tylus, Urszula; Ramaswamy, Nagappan; Liang, Wentao; Sougrati, Moulay-Tahar; Jaouen, Frédéric; Mukerjee, Sanjeev

    2015-06-01

    Replacement of noble metals in catalysts for cathodic oxygen reduction reaction with transition metals mostly create active sites based on a composite of nitrogen-coordinated transition metal in close concert with non-nitrogen-coordinated carbon-embedded metal atom clusters. Here we report a non-platinum group metal electrocatalyst with an active site devoid of any direct nitrogen coordination to iron that outperforms the benchmark platinum-based catalyst in alkaline media and is comparable to its best contemporaries in acidic media. In situ X-ray absorption spectroscopy in conjunction with ex situ microscopy clearly shows nitrided carbon fibres with embedded iron particles that are not directly involved in the oxygen reduction pathway. Instead, the reaction occurs primarily on the carbon-nitrogen structure in the outer skin of the nitrided carbon fibres. Implications include the potential of creating greater active site density and the potential elimination of any Fenton-type process involving exposed iron ions culminating in peroxide initiated free-radical formation.

  9. Carbon and nitrogen assimilation activities of deep subseafloor microbes analyzed by NanoSIMS

    Science.gov (United States)

    Morono, Y.; Terada, T.; Inagaki, F.

    2009-12-01

    Deep subseafloor microbes play significant roles on biogeochemical cycles with extremely low metabolic activities. The subseafloor microbial community consists mainly of uncultured components; hence, their growth and metabolic characteristics remain almost completely unknown. Here, we presnet in vitro isotopic evidence that the deep subseafloor microbes actively incooporate multiple carbon and nitrogen compounds into their biomass using NanoSIMS. We incubated methane hydrate-bearing deep marine sediments with small 13C-labeled glucose, acetate, pyruvate, bicarbonate, amino-acids and methane in the presence of 15N-labeled ammonia as a nitrogen source for 2 and 6 monthes under the anaerobic condition. Using NanoSIMS, we observed the cells that incooprated 13C- or 15N-labeled substrates such as 13C-glucose, pyruvate, and 15N-ammonia up to 50% of their cellular carbon or nitrogen mass. Assimilation of 13C- and 15N-labeled amino acids as well as 13C-bicarbonates by autotrophs was also observed while 13C-methane was found to be difficult to be used for the carbon source, regardless of the presence of some additional electron acceptors for the energy respiration. These results indicate that the metabolic activities of deep subseafloor microbes can be stimulated in vitro by adding potential carbon and nitrogen sources, providing new insights into the biogeochemical functioning of the deep subseaflor microbes and its ecosystem.

  10. Comparison of Cas9 activators in multiple species.

    Science.gov (United States)

    Chavez, Alejandro; Tuttle, Marcelle; Pruitt, Benjamin W; Ewen-Campen, Ben; Chari, Raj; Ter-Ovanesyan, Dmitry; Haque, Sabina J; Cecchi, Ryan J; Kowal, Emma J K; Buchthal, Joanna; Housden, Benjamin E; Perrimon, Norbert; Collins, James J; Church, George

    2016-07-01

    Several programmable transcription factors exist based on the versatile Cas9 protein, yet their relative potency and effectiveness across various cell types and species remain unexplored. Here, we compare Cas9 activator systems and examine their ability to induce robust gene expression in several human, mouse, and fly cell lines. We also explore the potential for improved activation through the combination of the most potent activator systems, and we assess the role of cooperativity in maximizing gene expression. PMID:27214048

  11. A novel soil manganese mechanism drives plant species loss with increased nitrogen deposition in a temperate steppe.

    Science.gov (United States)

    Tian, Qiuying; Liu, Nana; Bai, Wenming; Li, Linghao; Chen, Jiquan; Reich, Peter B; Yu, Qiang; Guo, Dali; Smith, Melinda D; Knapp, Alan K; Cheng, Weixin; Lu, Peng; Gao, Yan; Yang, An; Wang, Tianzuo; Li, Xin; Wang, Zhengwen; Ma, Yibing; Han, Xingguo; Zhang, Wen-Hao

    2016-01-01

    Loss of plant diversity with increased anthropogenic nitrogen (N) deposition in grasslands has occurred globally. In most cases, competitive exclusion driven by preemption of light or space is invoked as a key mechanism. Here, we provide evidence from a 9-yr N-addition experiment for an alternative mechanism: differential sensitivity of forbs and grasses to increased soil manganese (Mn) levels. In Inner Mongolia steppes, increasing the N supply shifted plant community composition from grass-forb codominance (primarily Stipa krylovii and Artemisia frigida, respectively) to exclusive dominance by grass, with associated declines in overall species richness. Reduced abundance of forbs was linked to soil acidification that increased mobilization of soil Mn, with a 10-fold greater accumulation of Mn in forbs than in grasses. The enhanced accumulation of Mn in forbs was correlated with reduced photosynthetic rates and growth, and is consistent with the loss of forb species. Differential accumulation of Mn between forbs and grasses can be linked to fundamental differences between dicots and monocots in the biochemical pathways regulating metal transport. These findings provide a mechanistic explanation for N-induced species loss in temperate grasslands by linking metal mobilization in soil to differential metal acquisition and impacts on key functional groups in these ecosystems.

  12. The emerging role of reactive oxygen and nitrogen species in redox biology and some implications for plasma applications to medicine and biology

    International Nuclear Information System (INIS)

    Reactive oxygen species (ROS) and the closely related reactive nitrogen species (RNS) are often generated in applications of atmospheric pressure plasmas intended for biomedical purposes. These species are also central players in what is sometimes referred to as ‘redox’ or oxidation-reduction biology. Oxidation-reduction biochemistry is fundamental to all of aerobic biology. ROS and RNS are perhaps best known as disease-associated agents, implicated in diabetes, cancer, heart and lung disease, autoimmune disease and a host of other maladies including ageing and various infectious diseases. These species are also known to play active roles in the immune systems of both animals and plants and are key signalling molecules, among many other important roles. Indeed, the latest research has shown that ROS/RNS play a much more complex and nuanced role in health and ageing than previously thought. Some of the most potentially profound therapeutic roles played by ROS and RNS in various medical interventions have emerged only in the last several years. Recent research suggests that ROS/RNS are significant and perhaps even central actors in the actions of antimicrobial and anti-parasite drugs, cancer therapies, wound healing therapies and therapies involving the cardiovascular system. Understanding the ways ROS/RNS act in established therapies may help guide future efforts in exploiting novel plasma medical therapies. The importance of ROS and RNS to plant biology has been relatively little appreciated in the plasma biomedicine community, but these species are just as important in plants. It appears that there are opportunities for useful applications of plasmas in this area as well. (topical review)

  13. The emerging role of reactive oxygen and nitrogen species in redox biology and some implications for plasma applications to medicine and biology

    Science.gov (United States)

    Graves, David B.

    2012-07-01

    Reactive oxygen species (ROS) and the closely related reactive nitrogen species (RNS) are often generated in applications of atmospheric pressure plasmas intended for biomedical purposes. These species are also central players in what is sometimes referred to as ‘redox’ or oxidation-reduction biology. Oxidation-reduction biochemistry is fundamental to all of aerobic biology. ROS and RNS are perhaps best known as disease-associated agents, implicated in diabetes, cancer, heart and lung disease, autoimmune disease and a host of other maladies including ageing and various infectious diseases. These species are also known to play active roles in the immune systems of both animals and plants and are key signalling molecules, among many other important roles. Indeed, the latest research has shown that ROS/RNS play a much more complex and nuanced role in health and ageing than previously thought. Some of the most potentially profound therapeutic roles played by ROS and RNS in various medical interventions have emerged only in the last several years. Recent research suggests that ROS/RNS are significant and perhaps even central actors in the actions of antimicrobial and anti-parasite drugs, cancer therapies, wound healing therapies and therapies involving the cardiovascular system. Understanding the ways ROS/RNS act in established therapies may help guide future efforts in exploiting novel plasma medical therapies. The importance of ROS and RNS to plant biology has been relatively little appreciated in the plasma biomedicine community, but these species are just as important in plants. It appears that there are opportunities for useful applications of plasmas in this area as well.

  14. Cellulose decomposition and associated nitrogen fixation by mixed cultures of Cellulomonas gelida and Azospirillum species or Bacillus macerans

    Energy Technology Data Exchange (ETDEWEB)

    Halsall, D.M.; Gibson, A.H.

    1985-10-01

    Mixed cultures of Cellulomonas gelida plus Azospirillum lipoferum or Azospirillum brasilense and C. gelida plus Bacillus macerans were shown to degrade cellulose and straw and to utilize the energy-yielding products to fix atmospheric nitrogen. This cooperative process was followed over 30 days in sand-based cultures in which the breakdown of 20% of the cellulose and 28 to 30% of the straw resulted in the fixation of 12 to 14.6 mg of N per g of cellulose and 17 to 19 mg of N per g of straw consumed. Cellulomonas species have certain advantages over aerobic cellulose-degrading fungi in being able to degrade cellulose at oxygen concentrations as low as 1% O/sub 2/ (vol/vol) which would allow a close association between cellulose-degrading and microaerobic diazotrophic microorganisms. Cultures inoculated with initially different proportions of A. brasilense and C. gelida all reached a stable ratio of approximately 1 Azospirillum/3 Cellulomonas cells.

  15. Stress Sensitivity Is Associated with Differential Accumulation of Reactive Oxygen and Nitrogen Species in Maize Genotypes with Contrasting Levels of Drought Tolerance.

    Science.gov (United States)

    Yang, Liming; Fountain, Jake C; Wang, Hui; Ni, Xinzhi; Ji, Pingsheng; Lee, Robert D; Kemerait, Robert C; Scully, Brian T; Guo, Baozhu

    2015-10-19

    Drought stress decreases crop growth, yield, and can further exacerbate pre-harvest aflatoxin contamination. Tolerance and adaptation to drought stress is an important trait of agricultural crops like maize. However, maize genotypes with contrasting drought tolerances have been shown to possess both common and genotype-specific adaptations to cope with drought stress. In this research, the physiological and metabolic response patterns in the leaves of maize seedlings subjected to drought stress were investigated using six maize genotypes including: A638, B73, Grace-E5, Lo964, Lo1016, and Va35. During drought treatments, drought-sensitive maize seedlings displayed more severe symptoms such as chlorosis and wilting, exhibited significant decreases in photosynthetic parameters, and accumulated significantly more reactive oxygen species (ROS) and reactive nitrogen species (RNS) than tolerant genotypes. Sensitive genotypes also showed rapid increases in enzyme activities involved in ROS and RNS metabolism. However, the measured antioxidant enzyme activities were higher in the tolerant genotypes than in the sensitive genotypes in which increased rapidly following drought stress. The results suggest that drought stress causes differential responses to oxidative and nitrosative stress in maize genotypes with tolerant genotypes with slower reaction and less ROS and RNS production than sensitive ones. These differential patterns may be utilized as potential biological markers for use in marker assisted breeding.

  16. Synoptic Sampling of Dissolved Nitrogen Species and Organic Carbon in the Rio Grande Basin

    Science.gov (United States)

    Villinski, J. E.; Hogan, J. F.; Brooks, P. D.; Haas, P. A.; Mills, S. K.

    2002-12-01

    Synoptic sampling has been performed along the Rio Grande from the headwaters in Colorado to Fort Quitman, Texas, south of El Paso. Samples from August 2001 and January 2002 were analyzed for nitrate (NO3-), ammonium (NH_{4}$+), total dissolved nitrogen (TDN), and dissolved organic carbon (DOC). DOC concentrations increase slowly between Colorado and southern New Mexico and then approximately double in Texas. Large sources of N during both sampling periods were the urban areas around Albuquerque and El Paso, Texas and Ciudad Juarez, Mexico, and agricultural regions in the Rincon and Mesilla valleys of southern New Mexico. Nitrate-N concentrations remained high south of Albuquerque to Elephant Butte reservoir in the summer, presumably due to lack of primary production. Inorganic N concentrations generally are higher in the winter than in the summer. During the summer, ammonium concentrations were greater than 100 mg N/l only at the outlet of Elephant Butte Reservoir, and in Texas. However, winter concentrations were on average an order of magnitude greater, again with the largest ammonium values (5000 \\mug N/l) in Texas. These patterns are consistent with a reduction in biological nutrient demand during the non-growing season.

  17. Tomato response traits to pathogenic Pseudomonas species: Does nitrogen limitation matter?

    Science.gov (United States)

    Royer, Mathilde; Larbat, Romain; Le Bot, Jacques; Adamowicz, Stéphane; Nicot, Philippe C; Robin, Christophe

    2016-03-01

    Induced chemical defence is a cost-efficient protective strategy, whereby plants induce the biosynthesis of defence-related compounds only in the case of pest attack. Plant responses that are pathogen specific lower the cost of defence, compared to constitutive defence. As nitrogen availability (N) in the root zone is one of the levers mediating the concentration of defence-related compounds in plants, we investigated its influence on response traits of tomato to two pathogenic bacteria, growing plants hydroponically at low or high N supply. Using two sets of plants for each level of N supply, we inoculated one leaf of one set of plants with Pseudomonas syringae, and inoculated the stem of other set of plants with Pseudomonas corrugata. Tomato response traits (growth, metabolites) were investigated one and twelve days after inoculation. In infected areas, P. syringae decreased carbohydrate concentrations whereas they were increased by P. corrugata. P. syringae mediated a redistribution of carbon within the phenylpropanoid pathway, regardless of N supply: phenolamides, especially caffeoylputrescine, were stimulated, impairing defence-related compounds such as chlorogenic acid. Inoculation of P. syringae produced strong and sustainable systemic responses. By contrast, inoculation of P. corrugata induced local and transient responses. The effects of pathogens on plant growth and leaf gas exchanges appeared to be independant of N supply. This work shows that the same genus of plant pathogens with different infection strategies can mediate contrasted plant responses.

  18. Comparison of Nitrogen Fertilizers, Induce and Zinc Addition on Glyphosate Efficacy on Three Different Weed Species.

    Directory of Open Access Journals (Sweden)

    Hussein F. Abouziena

    2014-05-01

    Full Text Available Herbicides are often tank-mixed with fertilizers to save time, labour, energy, and equipment costs. However addition of some additives with glyphosate may result in reducing glyphosate efficacy. Therefore we evaluated the potential of three nitrogen sources (ammonium sulphate (AMS at 2 or 4% w/v, ammonium nitrate (AN at 1 or 2% w/v, urea at 1 or 2 % w/v, nonionic adjuvant (Induce at 0.05% v/v and Zn at 250 g Zn/ha (1321 ppm to enhance glyphosate efficacy on pig weed (Amaranthus retroflexus L., crowfoot grass (Dactyloctenium egyptium L. and yellow nutsedge (Cyperus esculentus L. under greenhouse conditions. The results indicated that there were variations in susceptibility of the three weeds to glyphosate+adjuvant treatments. Addition of AN at 2% reduced the efficacy of glyphosate on crowfoot grass. There was an antagonistic effect between glyphosate herbicide and Zn; the phytotoxic effect of glyphosate on the three weeds was less than 50 %. Zinc tank-mixed with glyphosate resulted in a greater number of tubers and shoots per plant than the untreatedol. Addition of AN or urea at 2% reduced glyphosate efficacy by about 2.3 and 9 %, respectively, relative to their addition at 1%. Tankmixes of urea (1%, AN (1%, AMS (2% and Induce adjuvant (0.05% generally enhanced the efficacy of glyphosate (0.85 kg/ha, whereas the addition of Zn, as zinc sulphate, to glyphosate sprays adversely affected herbicide efficacy.

  19. Measurement of nitrogen species NO{sub y} at the exhaust of an aircraft engine combustor

    Energy Technology Data Exchange (ETDEWEB)

    Ristori, A. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), Palaiseau (France); Baudoin, C. [Societe Nationale d`Etude et de Construction de Moteurs d`Aviation (SNECMA), Villaroche (France)

    1997-12-31

    A research programme named AEROTRACE was supported by the EC (CEC contract AERA-CT94-0003) in order to investigate trace species measurements at the exhaust of aero-engines. Within this project, NO{sub y}, NO, HNO{sub 3} and HONO were measured at the exhaust of aircraft engine combustors. Major species (NO{sub y},NO) were measured by using a chemiluminescence instrument. Minor species (HNO{sub 3},HONO) were measured by using filter packs. Two combustors were tested under various running conditions; the first one at ONERA (Task 2) and the second one at DRA (Task 5). Results show that EI{sub NOy} < 50 g/kg, EI{sub HNO3} < 0.2 g/kg and EI{sub HONO} < 0.55 g/kg. Regarding ratios, (HNO{sub 3})/(NO{sub y}) < 0.5%, (HONO)/(NO{sub y}) < 8%, (HONO)/(NO{sub 2}) {approx} 19.2%, and (HNO{sub 3})/(NO{sub 2}) {approx} 0.8% was found. (author) 9 refs.

  20. Recurrent winter warming pulses enhance nitrogen cycling and soil biotic activity in temperate heathland and grassland mesocosms

    Directory of Open Access Journals (Sweden)

    J. Schuerings

    2014-06-01

    Full Text Available Winter air temperatures are projected to increase in the temperate zone, whereas snow cover is projected to decrease, leading to more extreme soil temperature variability, and potentially to changes in nutrient cycling. Therefore, we applied six winter warming pulses by infra-red heating lamps and surface heating wires in a field experiment over one winter in temperate heathland and grassland mesocosms. The experiment was replicated at two sites, a colder mountainous upland site with high snow accumulation and a warmer and dryer lowland site. Winter warming pulses enhanced soil biotic activity for both sites during winter, as indicated by 35% higher nitrogen (N availability in the soil solution, 40% higher belowground decomposition and a 25% increase in the activity of the enzyme cellobiohydrolase. The mobilization of N differed between sites, and the incorporation of 15N into leaves was reduced by 31% in response to winter warming pulses, but only at the cold site, with significant reductions occurring for three of four tested plant species at this site. Furthermore, there was a trend of increased N leaching in response to the recurrent winter warming pulses. Overall, projected winter climate change in the temperate zone, with less snow and more variable soil temperatures, appears important for shifts in ecosystem functioning (i.e. nutrient cycling. While the effects of warming pulses on plant N mobilization did not differ among sites, reduced plant 15N incorporation at the colder temperate site suggests that frost damage may reduce plant performance in a warmer world, with important implications for nitrogen cycling and nitrogen losses from ecosystems.

  1. Antimycobacterial and Antifungal Activities of Selected Four Salvia Species

    Directory of Open Access Journals (Sweden)

    Nur Tan

    2016-03-01

    Full Text Available The content of essential oils of endemic Salvia cilicica was analyzed by GC-FID and GC-MS techniques. Spathulenol (23.8 %, caryophyllene oxide (14.9 % and hexadecanoic acid (10.3 % were identified as the major components in the oil of Salvia cilicica. Additionally, in this study ethanol extracts of the aerial parts and essential oils of four Salvia species ( S. cilicica, S. officinalis, S. fruticosa, S. tomentosa , as well as the roots of S. cilicica were investigated their antimycobacterial and antifungal activities including infectious diseases. The antimycobacterial activity was analyzed against three Mycobacterium tuberculosis (sensitive-, resistant-standard strains and multidrug resistance clinical isolate strains and the antifungal activity was compared with two dermotophytes (Microsporum gypseum and Trichophyton mentagrophytes var. erinacei and three Candida species by the broth microdilution method. The essentials oils of the four tested Salvia species showed high antimycobacterial and antifungal activity (MIC between 0.2-12.5 mcg/mL in comparison to the aerial parts and root extracts . The antifungal and antimycobacterial potential of the ethanol extracts and essential oils were introduced to determine whether, Salvia species can be used in phytotherapy against the yeasts, dermatophytes and M. tuberculosis. To the best of our knowledge this is the first study of S. cilicica about their antimycobacterial and antifungal activities and chemical composition of its essential oils.

  2. Nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate synthase expression and activity in response to different nitrogen sources in nitrogen-starved wheat seedlings.

    Science.gov (United States)

    Balotf, Sadegh; Kavoosi, Gholamreza; Kholdebarin, Bahman

    2016-01-01

    The objective of this study was to examine the expression and activity of nitrate reductase (NR, EC 1.7.1.1), nitrite reductase (NiR, EC 1.7.2.2), glutamine synthetase (GS, EC 6.3.1.2), and glutamate synthase (GOGAT, EC 1.4.7.1) in response to potassium nitrate, ammonium chloride, and ammonium nitrate in nitrogen-starved wheat seedlings. Plants were grown in standard nutrient solution for 17 days and then subjected to nitrogen starvation for 7 days. The starved plants were supplied with potassium nitrate ammonium nitrate and ammonium chloride (50 mM) for 4 days and the leaves were harvested. The relative expression of NR, NiR, GS, and GOGAT as well as the enzyme activities were investigated. Nitrogen starvation caused a significant decrease both in transcript levels and in NR, NiR, GS, and GOGAT activities. Potassium nitrate and ammonium nitrate treatments restored NR, NiR, GS, and GOGAT expressions and activities. Ammonium chloride increased only the expressions and activities of GS and GOGAT in a dose-dependent manner. The results of our study highlight the differential effects between the type and the amount of nitrogen salts on NR, NiR, GS, and GOGAT activities in wheat seedlings while potassium nitrate being more effective.

  3. Large difference of inhibitive effect of nitrogen deposition on soil methane oxidation between plantations with N-fixing tree species and non-N-fixing tree species

    Science.gov (United States)

    Zhang, Wei; Zhu, Xiaomin; Liu, Lei; Fu, Shenglei; Chen, Hao; Huang, Juan; Lu, Xiankai; Liu, Zhanfeng; Mo, Jiangming

    2012-12-01

    The responses of soil methane (CH4) net fluxes to nitrogen (N) addition in a N-fixing tree species (Acacia auriculiformis (AA)) and a non-N-fixing tree species (Eucalyptus citriodora (EU)) plantation were studied in southern China. Treatments were conducted at each plantation with three N levels (0, 50, and 100 kg N ha-1 yr-1 for control, medium-N, and high-N treatment, respectively, abbreviated as C, MN, and HN). From August 2010 to July 2011, CH4 flux was measured biweekly using a static chamber and gas chromatography technique. The soils of both sites acted as sink of atmospheric CH4. The CH4 uptake rate in control of the AA site (36.3 ± 3.2 μg CH4-C m-2 h-1) was greater than that of the EU plantation (29.9 ± 0.9 μg CH4-C m-2 h-1). In the AA plantation, the averaged rates of CH4 uptake for the MN (28.6 ± 2.3 μg CH4-C m-2 h-1) and HN treatment (23.8 ± 2.8 μg CH4-C m-2 h-1) were decreased by 21% and 35%, respectively, compared to the control. However, there was no change of soil CH4 uptake between N-treated plots and the controls in the EU site. Our results indicated that there might be large difference of inhibitive effect of N deposition on soil CH4 oxidation between the AA and EU plantations. The projected increase of N deposition would weaken the capability of N-fixing tree species plantations for atmospheric CH4 sink in tropical and subtropical regions.

  4. Determination of nitrogen in boron carbide by instrumental photon activation analysis.

    Science.gov (United States)

    Merchel, Silke; Berger, Achim

    2007-05-01

    Boron carbide is widely used as industrial material, because of its extreme hardness, and as a neutron absorber. As part of a round-robin exercise leading to certification of a new reference material (ERM-ED102) which was demanded by the industry we analysed nitrogen in boron carbide by inert gas fusion analysis (GFA) and instrumental photon activation analysis (IPAA) using the 14N(gamma,n)13N nuclear reaction. The latter approach is the only non-destructive method among all the methods applied. By using photons with energy below the threshold of the 12C(gamma,n)11C reaction, we hindered activation of matrix and other impurities. A recently installed beam with a very low lateral activating flux gradient enabled us to homogeneously activate sample masses of approximately 1 g. Taking extra precautions, i.e. self-absorption correction and deconvolution of the complex decay curves, we calculated a nitrogen concentration of 2260+/-100 microg g-1, which is in good agreement with our GFA value of 2303+/-64 microg g-1. The values are the second and third highest of a rather atypical (non-S-shape) distribution of data of 14 round-robin participants. It is of utmost importance for the certification process that our IPAA value is the only one not produced by inert gas fusion analysis and, therefore, the only one which is not affected by a possible incomplete release of nitrogen from high-melting boron carbide.

  5. Diversity and Activity of Lysobacter Species from Disease Suppressive Soils.

    Science.gov (United States)

    Gómez Expósito, Ruth; Postma, Joeke; Raaijmakers, Jos M; De Bruijn, Irene

    2015-01-01

    The genus Lysobacter includes several species that produce a range of extracellular enzymes and other metabolites with activity against bacteria, fungi, oomycetes, and nematodes. Lysobacter species were found to be more abundant in soil suppressive against the fungal root pathogen Rhizoctonia solani, but their actual role in disease suppression is still unclear. Here, the antifungal and plant growth-promoting activities of 18 Lysobacter strains, including 11 strains from Rhizoctonia-suppressive soils, were studied both in vitro and in vivo. Based on 16S rRNA sequencing, the Lysobacter strains from the Rhizoctonia-suppressive soil belonged to the four species Lysobacter antibioticus, Lysobacter capsici, Lysobacter enzymogenes, and Lysobacter gummosus. Most strains showed strong in vitro activity against R. solani and several other pathogens, including Pythium ultimum, Aspergillus niger, Fusarium oxysporum, and Xanthomonas campestris. When the Lysobacter strains were introduced into soil, however, no significant and consistent suppression of R. solani damping-off disease of sugar beet and cauliflower was observed. Subsequent bioassays further revealed that none of the Lysobacter strains was able to promote growth of sugar beet, cauliflower, onion, and Arabidopsis thaliana, either directly or via volatile compounds. The lack of in vivo activity is most likely attributed to poor colonization of the rhizosphere by the introduced Lysobacter strains. In conclusion, our results demonstrated that Lysobacter species have strong antagonistic activities against a range of pathogens, making them an important source for putative new enzymes and antimicrobial compounds. However, their potential role in R. solani disease suppressive soil could not be confirmed. In-depth omics'-based analyses will be needed to shed more light on the potential contribution of Lysobacter species to the collective activities of microbial consortia in disease suppressive soils. PMID:26635735

  6. Gelidium elegans, an edible red seaweed, and hesperidin inhibit lipid accumulation and production of reactive oxygen species and reactive nitrogen species in 3T3-L1 and RAW264.7 cells.

    Science.gov (United States)

    Jeon, Hui-Jeon; Seo, Min-Jung; Choi, Hyeon-Son; Lee, Ok-Hwan; Lee, Boo-Yong

    2014-11-01

    Gelidium elegans is an edible red alga native to the intertidal area of northeastern Asia. We investigated the effect of G. elegans extract and its main flavonoids, rutin and hesperidin, on lipid accumulation and the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in 3T3-L1 and RAW264.7 cells. Our data show that G. elegans extract decreased lipid accumulation and ROS/RNS production in a dose-dependent manner. The extract also inhibited the mRNA expression of adipogenic transcription factors, such as peroxisome proliferator-activated receptor gamma and CCAAT/enhancer-binding protein alpha, while enhancing the protein expression of the antioxidant enzymes superoxide dismutases 1 and 2, glutathione peroxidase, and glutathione reductase compared with controls. In addition, lipopolysaccharide-induced nitric oxide production was significantly reduced in G. elegans extract-treated RAW264.7 cells. In analysis of the effects of G. elegans flavonoids on lipid accumulation and ROS/RNS production, only hesperidin showed an inhibitory effect on lipid accumulation and ROS production; rutin did not affect adipogenesis and ROS status. The antiadipogenic effect of hesperidin was evidenced by the downregulation of peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding protein alpha, and fatty acid binding protein 4 gene expression. Collectively, our data suggest that G. elegans is a potential food source containing antiobesity and antioxidant constituents.

  7. ANTIVENOM ACTIVITIES OF SOME SPECIES OF ANDROGRAPHIS WALL

    OpenAIRE

    Balu, S.; Alagesaboopathi, C.

    1995-01-01

    Antivenom activities of the alcoholic extracts of three species of Andrographis wall, were measured at a concentration of 10,25,50,75 and 100 μg/ml by in vitro assay of HRBC membrane lysis. All the extracts were found to be effective in the inhibition of in vitro HRBC lysis. The maximum antivenom activity was found in the alcoholicextract of Andrographis paniculata Nees.

  8. Proton, Helium and Carbon Radiation Beam Targeting Reactive Oxygen, Nitrogen and Halogenated Species in TRIM-SRIM Model

    International Nuclear Information System (INIS)

    Nowadays proton beam radiation therapy is considered in few centers for management of malignancies. This study is aimed to explore the effect of proton, helium or carbon irradiation on free radicals. This study was conducted in department of Physiology/Medical physics, College of Medicine, Al-Mustansiriya University in Baghdad, Iraq during October 2009. TRIM-SRIM software version 1998 and2003 were used for computed Bragg peak and for calculated the effect of proton, helium and carbon ions against free radicals related to oxygen, nitrogen and halogen species. The lowest stopping power near Bragg's peak of proton targeting free radicals was against superoxide anion and its curve (the stopping power against energy) was shifted down while that of peroxynitrite(ONOO-) was shifted up. The stopping powers of helium targeting all studied free radicals were lower than corresponding proton irradiation but it required higher energy. Lower stopping power of carbon irradiation targeted hydroxyl(OH-) and halogenated radicals than the other reactive species were observed. It concludes that such from of external beam irradiation is associated with direct scavenging effect on free radicals of whatever sources.

  9. Antioxidant, Antimicrobial and Antiproliferative Activities of Five Lichen Species

    Directory of Open Access Journals (Sweden)

    Snežana Marković

    2011-08-01

    Full Text Available The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+ bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells.

  10. Activity during natural hibernation in three species of Vespertilionid bats

    NARCIS (Netherlands)

    Daan, Serge

    1973-01-01

    1. Patterns of winter-activity in three species of bats (Myotis mystacinus, M. daubentoni, M. dasycneme) were studied in three hibernation quarters in The Netherlands. The methods of investigation involved: individual marking, automatic recording of intracave and extracave flights and assessment of

  11. Effects of Nitrogen Doping on Microstructure and Photocatalytic Activity of Nanocrystalline TiO2 Powders

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Nitrogen-doped TiO2 nanocrystalline powders were prepared by hydrolysis of tetrachloride titanium (TiCl4) in a mixed solution of ethanol and ammonium nitrate (NH4NO3) at ambient temperature and atmosphere followed by calcination at 400 C for 2 h in air. FTIR spectra demonstrate that amine group in original gel is eliminated by calcination, and the TiO2 powder is liable to absorb water onto its surface and into its capillary pore. XRD and SEM results show that the average size of nanocrystalline TiO2 particles is no more than 60 nm and with increasing the calcination temperature, the size of particles increases. XPS studies indicate the nitrogen atom enters into the TiO2 lattice and occupies the position of oxygen atom. The nitrogen doping not only depresses the grain growth of TiO2 particles, but also reduces the phase transformation temperature of anatase to rutile. The photocatalytic activity of the nitrogen-doped TiO2 powders has been evaluated by experiments ofphotocatalytic degradation aqueous methylene blue.

  12. Optimum operation conditions of nitrogen and phosphorus removal by a biofilm-activated-sludge system

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In the biofilm and activated sludge combined system, denitrifying bacteria attached on the fibrous carriers in the anoxic tank, while the sludge containing nitrifying and phosphorus removal bacteria was only recirculated between the aerobic and anaerobic tanks. Therefore, the factors affected and restricted nitrification, denitrification and phosphorus removal in a traditional A/A/O process were resolved. This paper describes the optimum operation conditions for nitrogen and phosphorus removal using this system.

  13. Effect of reduced nitrogen deposition on microbial activity, abundance and diversity in forest soils

    OpenAIRE

    Enowashu, Esther Eneckeh

    2012-01-01

    The deposition of nitrogen has increased many-fold due to anthropogenic activities. Since forest ecosystems are often limited by N availability, elevated N inputs from the atmosphere can have a fertilization effect but in the long-term, excess N can influence above- and below-ground production. One of the consequences of N deposition and increased N inputs is a shift in microbial community structure and function as ecosystems move towards N saturation. Soil microorganisms through the action o...

  14. Influence of Water Activated by Far infrared Porous Ceramics on Nitrogen Absorption in the Pig Feed.

    Science.gov (United States)

    Meng, Junping; Liu, Jie; Liang, Jinsheng; Zhang, Hongchen; Ding, Yan

    2016-04-01

    Under modern and, intensive feeding livestock and poultry density has increased, and brought a deterioration of the farm environment. The livestock and their excrement generate harmful gases such as ammonia, etc. which restricted the sustainable development and improvement of production efficiency of animal husbandry. In this paper, a new kind of far infrared porous ceramics was prepared to activate, the animal drinking water. The activated water and common water were then supplied to pigs, and the fresh pig feces of experimental group and:control group were collected on a regular basis. The residual protein content in feces was tested by Kjeldahl nitrogen method to study the influence law of the porous ceramics on absorbing nitrogen element in animal feces. The results showed that compared with the control group, the protein content in the experimental group decreased on average by 39.2%. The activated drinking water was conducive to the absorption of nitrogen in pig feed. The clusters of water molecules became smaller under the action of the porous ceramics. Hence, they were easy to pass through the water protein channel on the cell membrane for speeding up the metabolism.

  15. Hierarchically porous carbons with optimized nitrogen doping as highly active electrocatalysts for oxygen reduction

    Science.gov (United States)

    Liang, Hai-Wei; Zhuang, Xiaodong; Brüller, Sebastian; Feng, Xinliang; Müllen, Klaus

    2014-09-01

    Development of efficient, low-cost and stable electrocatalysts as the alternative to platinum for the oxygen reduction reaction is of significance for many important electrochemical devices, such as fuel cells, metal-air batteries and chlor-alkali electrolysers. Here we report a highly active nitrogen-doped, carbon-based, metal-free oxygen reduction reaction electrocatalyst, prepared by a hard-templating synthesis, for which nitrogen-enriched aromatic polymers and colloidal silica are used as precursor and template, respectively, followed by ammonia activation. Our protocol allows for the simultaneous optimization of both porous structures and surface functionalities of nitrogen-doped carbons. Accordingly, the prepared catalysts show the highest oxygen reduction reaction activity (half-wave potential of 0.85 V versus reversible hydrogen electrode with a low loading of 0.1 mg cm-2) in alkaline media among all reported metal-free catalysts. Significantly, when used for constructing the air electrode of zinc-air battery, our metal-free catalyst outperforms the state-of the-art platinum-based catalyst.

  16. [Response of active nitrogen to salinity in a soil from the Yellow River Delta].

    Science.gov (United States)

    Li, Ling; Qiu, Shao-Jun; Chen, Yin-Ping; Zhao, Xi-Men; Liu, Jing-Tao; Lu, Zhao-Hu

    2014-06-01

    Soil salinity can inhibit the processes of nitrogen cycle, and the active nitrogen is the important indicator to reflect the turnover of nitrogen. A laboratory experiment was conducted to study the effect of soil salinity on the active nitrogen in a soil of the Yellow River Delta incubated aerobically under 25 degrees C for 45 days. Four levels of salinity (S1: 0.1%, S2: 0.5%, S3: 0.9%, S4: 1.3%) were imposed using NaCl (mass fraction), and glucose with or without NH4Cl were added to the soils. NO3(-) -N, NH4(+) -N, total soluble nitrogen (TSN) and microbial biomass nitrogen (MBN) were monitored. Results showed that NO3(-)-N was significantly higher in the low salinity soil (S1, S2) than in the high salinity soil (S3, S4) under the control and with NH4Cl addition, and especially the difference was larger with NH4Cl addition. Comparing with the control, NO3(-) -N was increased significantly in S1 and S2. NO3(-) -N was decreased significantly with glucose addition, and there was no difference among the four salinity soils during the whole incubation period. NH4(+) -N was significantly higher in the high salinity soil (S3, S4) than in the low salinity soil (S1, S2), and it was increased particularly in S4 after day 5. With the addition of NH4Cl, NH4(+) -N was increased in S3 and S4. MBN was higher in the low salinity soil than in the high salinity soil, and it was not increased with NH4Cl addition, though TSN was increased. With glucose addition, MBN was increased by 89.9% - 130.9% in the low salinity soil (S1, S2) and 36.9% - 79.5% in the high salinity soil (S3, S4). It was suggested that soil salinity had influence on N transformation, and high salinity inhibited the transformation and assimilation of N by microorganism. The addition of C depressed the effect of salinity, and improved the microbial activity. The application of organic matter is an effective measure to improve N transformation in saline soils.

  17. Reactive nitrogen species; devastating intracellular players and melatonin as a defender

    Directory of Open Access Journals (Sweden)

    Lucien C. Manchester

    2011-04-01

    Full Text Available It is widely accepted that reactive oxygen species (ROS readily cause cellular damage (i.e., oxidative stress and play an important role in the pathogenesis of a variety of human diseases and sequelae. Since the first seminal free radical studies by Harman in 1950’s, oxidative stress has gained much attention and many studies have confirmed that free radicals especially those that are oxygen-based such as the superoxide anion, hydroxyl radical, and non-radical hydrogen peroxide are harmful molecules intracellularly. However, H2O2 for example, functions as an important second messenger at physiological levels and involves a vast number of pathways within cells. Therefore, the general belief can be summarized as “oxygen-based free radicals are harmful when they are produced at high levels within a certain time period”. Since cells are well equipped with an anti-oxidative defense system both enzymatically and non-enzymatically, oxidative stress can only appear if the amount of ROS produced in the cells exceeds the neutralizing capacity of anti-oxidative defense system. In this case, ... [J Exp Integr Med 2011; 1(2.000: 63-65

  18. 2-Styrylchromones: novel strong scavengers of reactive oxygen and nitrogen species

    OpenAIRE

    Gomes, Ana; Fernandes, Eduarda; Silva, Artur; Pinto, Diana; Santos, Clementina M.M.; Cavaleiro, José; Lima, José Costa

    2007-01-01

    http://apps.isiknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=1&SID=S2NjaL1GBbk143plPl1&page=1&doc=1&colname=WOS 2-Styrylchromones are a small group of naturally occurring chromones, vinylogues of flavones (2-phenylchromones). Natural and synthetic 2-styrylchromones have been tested in different biological systems, showing activities with potential therapeutic applications. In particular, the potential and hitherto understudied antioxidant behavior of these com...

  19. Quality assessment and antiplasmodial activity of West African Cochlospermum species.

    Science.gov (United States)

    Lamien-Meda, Aline; Kiendrebeogo, Martin; Compaoré, Moussa; Meda, Roland N T; Bacher, Markus; Koenig, Karin; Pacher, Thomas; Fuehrer, Hans-Peter; Noedl, Harald; Willcox, Merlin; Novak, Johannes

    2015-11-01

    The present study focuses on development of phytochemical methods for quality assessment of two West-African Cochlospermum species (Cochlospermum planchonii and Cochlospermum tinctorium) traditionally used for malaria treatment in Burkina Faso. Antimalarial activity of preparations from dried rhizomes (decoction) was tested against the chloroquine-sensitive Plasmodium strain 3D7 using the histidine-rich protein II (HRP2) drug susceptibility assay and compared with extract preparations using organic solvents of different polarity. Two main apocarotenoids were isolated from rhizomes of C. planchonii and unambiguously identified as dihydrocochloxanthine and cochloxanthine by spectroscopic methods. Comparative HPLC analyses of thirty-nine (39) samples from markets and from collections in natural habitats of both species showed a high variability in the accumulation of cochloxanthines and related carotenoids which were proven to be characteristic for rhizomes of both species and generally absent in leaves. Furthermore, content of total phenolics and antioxidant activities (DPPH and FRAP) as well as haemolytic activity of various extracts was tested. The HPLC method presented here was validated and provides a good separation of both compounds including 10 minor carotenoids. Extracts from both species and pure cochloxanthine offered pronounced antioxidant activities and weak haemolytic activity while, in contrast, dihydrocochloxanthine had a strong haemolytic effect at the highest concentration analysed. However, cochloxanthine as well as dihydrocochloxanthine showed erythroprotective effects against the haemolytic activity of the reference saponin. Moderate antiplasmodial activity between 16 and 63 μg/ml were observed with all tested extracts, and lower IC50 values were obtained with pure dihydrocochloxanthine (IC50=6.9 μg/ml), cochloxanthine (IC50=6.8 μg/ml), the DCM fraction (IC50=2.4 μg/ml) and the ethyl acetate fraction (IC50=11.5μg/ml) derived from a methanolic

  20. Azospirillum Inoculation Alters Nitrate Reductase Activity and Nitrogen Uptake in Wheat Plant under Water Deficit Conditions

    Directory of Open Access Journals (Sweden)

    N. Aliasgharzad N. Aliasgharzad

    2014-01-01

    Full Text Available Water deficit stress usually diminishes nitrogen uptake by plants. There are evidences that some nitrogen fixing bacteria can alleviate this stress by supplying nitrogen and improving its metabolism in plants. Four Azospirillum strains, A. lipoferum AC45-II, A. brasilense AC46-I, A. irakense AC49-VII and A. irakense AC51-VI were tested for nitrate reductase activity (NRA. In a pot culture experiment using a sandy loam soil, wheat plants (Triticum aestivum L. cv. Sardari were inoculated with these bacterial strains and three ranges of soil water potential (W1: -10 to -20, W2: -40 to -50 and W3: -65 to -75 kPa were applied to the pots. All strains were positive in NRA test and the highest (7.63mg NO2-N.L-1.48h-1 was recorded for AC49-VII and the least (0.23mg NO2-N.L-1.48h-1 was belong to AC51-VI. Leaf and root NRA, root and shoot nitrogen concentrations, and dry weights of root and shoot decreased by increasing water deficit stress. All four bacterial strains caused a significant enhancement in root NRA and in each water deficit level, the higher root NRA was recorded in AC46-I and AC49-VII inoculated plants. The highest leaf NRA was achieved by AC49-VII. The mean increment of root NRA by bacterial strains was 171% compared to the non-bacterial plants. Moreover, at the highest level of water deficit stress, the highest dry weight and nitrogen concentration in root and shoot were obtained by AC46-I and AC49-VII treatments.

  1. Nitrate reductase activity and its relationship with applied nitrogen in soybean

    International Nuclear Information System (INIS)

    Field experiments were conducted to study the nitrate reductase activity and its relationship to nitrogen by using frame tests (pot without bottom), sand culture and 15N-urea at transplanting in soybean variety Suinong 14. Results showed that the activity of nitrate reductase in leaf changed as a signal peak curve with the soybean growth, lower in vegetative growth phase, higher in reproductive growth period and reached the peak in blooming period, then decreased gradually. Nitrogen application showed obvious effect on the nitrate reductase activity. The activities of nitrate reductase in leaves followed the order of N135 > N90 > N45 > N0 in vegetative growth stage, no clear regularity was found during the whole reproductive growth period. The activities of nitrate reductase in leaves were accorded with the order of upper leaves > mid leaves > lower leaves, and it was very significant differences (P15N labeling method during beginning seed stage and full seed stage shown that 15N abundance in various organs at different node position also followed the same order, suggesting that high level of nitrate reductase activity at upper leaves of soybean promoted the assimilation of NO3-. (authors)

  2. ADSORPTION ISOTHERMS AND POTENTIAL DISTRIBUTIONS OF NITROGEN ON VARIOUS ACTIVATED CARBONS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The adsorption isotherms of four activated carbons (Norit RB1, Chemviron BPL, Monolit, and Ambersorb-572) have been examined by nitrogen adsorption at 77.5 K. A method for adsorption potential distribution calculation has been proposed based on the adsorption isotherms. This distribution provides information about possible changes in the Gibbs free energy caused by the energetic and geometrical heterogeneities of an activated carbon as well as by the adsorbate-related entropic effects. The general character of the adsorption potential distribution is clearly visible by its simple relation to the micropore and mesopore distribution.

  3. Manipulation of environmental oxygen modifies reactive oxygen and nitrogen species generation during myogenesis

    Directory of Open Access Journals (Sweden)

    Rachel McCormick

    2016-08-01

    Data demonstrate that satellite cell proliferation increased when cells were grown in 6% O2 compared with 20% O2. Myoblasts grown in 20% O2 showed an increase in DCF fluorescence and DHE oxidation compared with myoblasts grown at 6% O2. Myotubes grown in 20% O2 also showed an increase in DCF and DAF-FM fluorescence and DHE oxidation compared with myotubes grown in 6% O2. The catalase and MnSOD contents were also increased in myoblasts and myotubes that were maintained in 20% O2 compared with myoblasts and myotubes grown in 6% O2. These data indicate that intracellular RONS activities in myoblasts and myotubes at rest are influenced by changes in environmental oxygen concentration and that the increased ROS may influence myogenesis in a negative manner.

  4. Mineralogical impact on long-term patterns of soil nitrogen and phosphorus enzyme activities

    Science.gov (United States)

    Mikutta, Robert; Turner, Stephanie; Meyer-Stüve, Sandra; Guggenberger, Georg; Dohrmann, Reiner; Schippers, Axel

    2014-05-01

    Soil chronosequences provide a unique opportunity to study microbial activity over time in mineralogical diverse soils of different ages. The main objective of this study was to test the effect of mineralogical properties, nutrient and organic matter availability over whole soil pro-files on the abundance and activity of the microbial communities. We focused on microbio-logical processes involved in nitrogen and phosphorus cycling at the 120,000-year Franz Josef soil chronosequence. Microbial abundances (microbial biomass and total cell counts) and enzyme activities (protease, urease, aminopeptidase, and phosphatase) were determined and related to nutrient contents and mineralogical soil properties. Both, microbial abundances and enzyme activities decreased with soil depth at all sites. In the organic layers, microbial biomass and the activities of N-hydrolyzing enzymes showed their maximum at the intermediate-aged sites, corresponding to a high aboveground biomass. In contrast, the phosphatase activity increased with site age. The activities of N-hydrolyzing enzymes were positively correlated with total carbon and nitrogen contents, whereas the phosphatase activity was negatively correlated with the phosphorus content. In the mineral soil, the enzyme activities were generally low, thus reflecting the presence of strongly sorbing minerals. Sub-strate-normalized enzyme activities correlated negatively to clay content as well as poorly crystalline Al and Fe oxyhydroxides, supporting the view that the evolution of reactive sec-ondary mineral phases alters the activity of the microbial communities by constraining sub-strate availability. Our data suggest a strong mineralogical influence on nutrient cycling par-ticularly in subsoil environments.

  5. Gupta Nitrogen cycling in summer active perennial grass systems in South Australia: Non-symbiotic nitrogen fixation

    NARCIS (Netherlands)

    Gupta, V.V.S.R.; Kroker, S.J.; Hicks, M.; Davoren, W.; Descheemaeker, K.K.E.; Llewellyn, R.

    2014-01-01

    Non-symbiotic nitrogen (N2) fixation by diazotrophic bacteria is a potential source for biological N inputs in non-leguminous crops and pastures. Perennial grasses generally add larger quantities of above- and belowground plant residues to soil, and so can support higher levels of soil biological ac

  6. Active Optical Sensing of Spring Maize for In-Season Diagnosis of Nitrogen Status Based on Nitrogen Nutrition Index

    Directory of Open Access Journals (Sweden)

    Tingting Xia

    2016-07-01

    Full Text Available The nitrogen (N nutrition index (NNI is a reliable indicator of crop N status and there is an urgent need to develop efficient technologies for non-destructive estimation of NNI to support the practical applications of precision N management strategies. The objectives of this study were to: (i validate a newly established critical N dilution curve for spring maize in Northeast China; (ii determine the potential of using the GreenSeeker active optical sensor to non-destructively estimate NNI; and (iii evaluate the performance of different N status diagnostic approaches based on estimated NNI via the GreenSeeker sensor measurements. Four field experiments involving six N rates (0, 60, 120,180, 240, and 300 kg·ha−1 were conducted in 2014 and 2015 in Lishu County, Jilin Province in Northeast China. The results indicated that the newly established critical N dilution curve was suitable for spring maize N status diagnosis in the study region. Across site-years and growth stages (V5–V10, GreenSeeker sensor-based vegetation indices (VIs explained 87%–90%, 87%–89% and 83%–84% variability of leaf area index (LAI, aboveground biomass (AGB and plant N uptake (PNU, respectively. However, normalized difference vegetation index (NDVI became saturated when LAI > 2 m2·m−2, AGB > 3 t·ha−1 or PNU > 80 kg·ha−1. The GreenSeeker-based VIs performed better for estimating LAI, AGB and PNU at V5–V6 and V7–V8 than the V9–V10 growth stages, but were very weakly related to plant N concentration. The response index calculated with GreenSeeker NDVI (RI–NDVI and ratio vegetation index (R2 = 0.56–0.68 performed consistently better than the original VIs (R2 = 0.33–0.55 for estimating NNI. The N status diagnosis accuracy rate using RI–NDVI was 81% and 71% at V7–V8 and V9–V10 growth stages, respectively. We conclude that the response indices calculated with the GreenSeeker-based vegetation indices can be used to estimate spring maize NNI non

  7. Leghemoglobin green derivatives with nitrated hemes evidence production of highly reactive nitrogen species during aging of legume nodules.

    Science.gov (United States)

    Navascués, Joaquín; Pérez-Rontomé, Carmen; Gay, Marina; Marcos, Manuel; Yang, Fei; Walker, F Ann; Desbois, Alain; Abián, Joaquín; Becana, Manuel

    2012-02-14

    Globins constitute a superfamily of proteins widespread in all kingdoms of life, where they fulfill multiple functions, such as efficient O(2) transport and modulation of nitric oxide bioactivity. In plants, the most abundant Hbs are the symbiotic leghemoglobins (Lbs) that scavenge O(2) and facilitate its diffusion to the N(2)-fixing bacteroids in nodules. The biosynthesis of Lbs during nodule formation has been studied in detail, whereas little is known about the green derivatives of Lbs generated during nodule senescence. Here we characterize modified forms of Lbs, termed Lba(m), Lbc(m), and Lbd(m), of soybean nodules. These green Lbs have identical globins to the parent red Lbs but their hemes are nitrated. By combining UV-visible, MS, NMR, and resonance Raman spectroscopies with reconstitution experiments of the apoprotein with protoheme or mesoheme, we show that the nitro group is on the 4-vinyl. In vitro nitration of Lba with excess nitrite produced several isomers of nitrated heme, one of which is identical to those found in vivo. The use of antioxidants, metal chelators, and heme ligands reveals that nitration is contingent upon the binding of nitrite to heme Fe, and that the reactive nitrogen species involved derives from nitrous acid and is most probably the nitronium cation. The identification of these green Lbs provides conclusive evidence that highly oxidizing and nitrating species are produced in nodules leading to nitrosative stress. These findings are consistent with a previous report showing that the modified Lbs are more abundant in senescing nodules and have aberrant O(2) binding. PMID:22308405

  8. Large Roads Reduce Bat Activity across Multiple Species

    OpenAIRE

    Justin Kitzes; Adina Merenlender

    2014-01-01

    Although the negative impacts of roads on many terrestrial vertebrate and bird populations are well documented, there have been few studies of the road ecology of bats. To examine the effects of large roads on bat populations, we used acoustic recorders to survey bat activity along ten 300 m transects bordering three large highways in northern California, applying a newly developed statistical classifier to identify recorded calls to the species level. Nightly counts of bat passes were analyz...

  9. Compositions comprising a polypeptide having cellulolytic enhancing activity and a nitrogen-containing compound and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Quinlan, Jason; Xu, Feng; Sweeney, Matthew

    2016-05-31

    The present invention relates to compositions comprising: a polypeptide having cellulolytic enhancing activity and a nitrogen-containing compound. The present invention also relates to methods of using the compositions.

  10. Plant Functional Diversity Can Be Independent of Species Diversity: Observations Based on the Impact of 4-Yrs of Nitrogen and Phosphorus Additions in an Alpine Meadow

    OpenAIRE

    Wei Li; Ji-Min Cheng; Kai-Liang Yu; Howard E. Epstein; Liang Guo; Guang-Hua Jing; Jie Zhao; Guo-Zhen Du

    2015-01-01

    Past studies have widely documented the decrease in species diversity in response to addition of nutrients, however functional diversity is often independent from species diversity. In this study, we conducted a field experiment to examine the effect of nitrogen and phosphorus fertilization ((NH4)2 HPO4) at 0, 15, 30 and 60 g m-2 yr-1 (F0, F15, F30 and F60) after 4 years of continuous fertilization on functional diversity and species diversity, and its relationship with productivity in an alp...

  11. Nitrogen Species in Soil, Sediment, and Ground Water at a Former Sewage-Treatment Wastewater Lagoon: Naval Air Station Whidbey Island, Island County, Washington

    Science.gov (United States)

    Cox, S.E.; Dinicola, R.S.; Huffman, R.L.

    2007-01-01

    The potential for contamination of ground water from remnant sewage sludge in re-graded sediments of a deconstructed sewage-treatment lagoon was evaluated. Ground-water levels were measured in temporary drive-point wells, and ground-water samples were collected and analyzed for nutrients and other water-quality characteristics. Composite soil and sediment samples were collected and analyzed for organic carbon and nitrogen species. Multiple lines of evidence, including lack of appreciable organic matter in sediments of the former lagoon, agronomic analysis of nitrogen, the sequestration of nitrogen in the developing soils at the former lagoon, and likely occurrence of peat deposits within the aquifer material, suggest that the potential for substantial additions of nitrogen to ground water beneath the former sewage lagoon resulting from remnant sewage sludge not removed from the former lagoon are small. Concentrations of nitrogen species measured in ground-water samples were small and did not exceed the established U.S. Environmental Protection Agency's maximum contaminant levels for nitrate (10 milligrams per liter). Concentrations of nitrate in ground-water samples were less than the laboratory reporting limit of 0.06 milligram per liter. Seventy to 90 percent of the total nitrogen present in ground water was in the ammonia form with a maximum concentration of 7.67 milligrams per liter. Concentrations of total nitrogen in ground water beneath the site, which is the sum of all forms of nitrogen including nitrate, nitrite, ammonia, and organic nitrogen, ranged from 1.15 to 8.44 milligrams per liter. Thus, even if all forms of nitrogen measured in ground water were converted to nitrate, the combined mass would be less than the maximum contaminant level. Oxidation-reduction conditions in ground water beneath the former sewage lagoon were reducing. Given the abundant supply of ambient organic carbon in the subsurface and in ground water at the former lagoon, any

  12. Seasonal and yearly variations in light use and nitrogen use by seedlings of four deciduous broad-leaved tree species invading larch plantations.

    Science.gov (United States)

    Kitaoka, Satoshi; Koike, Takayoshi

    2005-04-01

    Several deciduous broad-leaved tree species, differing in leaf phenology, invade larch (Larix kaempferii (Lamb.) Carrière) plantations in Japan. The understory light environment of larch forests changes drastically between the leafy and leafless periods. To determine how the invading seedlings exploit the changing light environment, and if phenological differences reflect the light- and nitrogen-use traits of the seedlings, we measured leaf phenology, seasonal changes in light-saturated photosynthetic rate (P(sat)), leaf nitrogen (N) content (N(area)), chlorophyll/nitrogen ratio (Chl/N), specific leaf area (SLA) and N remobilization rate (NRMR) over 3 years. The mid-successional or gap-phase species, Magnolia hypoleuca Siebold & Zucc., had a short leafy period and high P(sat) and NRMR. In contrast, two late-successional tree species, Prunus ssiori Friedr. Schmidt, which undergoes leaf flush before larch, and Carpinus cordata Blume, which maintains green leaves until frost, both had low P(sat) and NRMR but exploited the opportunity for growth during the period when the larch canopy trees were leafless. Quercus mongolica Fisch. ex Ledeb. var. crispula (Blume) Ohashi, a mid-late-successional species that underwent leaf flush at the same time as the overstory larch, had values of photosynthetic parameters between those of the gap-phase and late-successional species. Among species, M. hypoleuca and Q. mongolica had higher photosynthetic rates and photosynthetic N-use efficiencies. In all species, the relationship between N(area) and P(sat) showed species-specific yearly fluctuations; however, there was no yearly fluctuation in the relationship between N(area) and P(sat) at CO2 saturation. Yearly fluctuations in the N(area)-P(sat) relationship appeared to be induced by changes in SLA and N-use characteristics, which in turn are affected by climatic variations.

  13. Effects of Nitrogen Addition on Leaf Decomposition of Single-Species and Litter Mixture in Pinus tabulaeformis Forests

    Directory of Open Access Journals (Sweden)

    Jinsong Wang

    2015-12-01

    Full Text Available The litter decomposition process is closely correlated with nutrient cycling and the maintenance of soil fertility in the forest ecosystem. In particular, the intense environmental concern about atmospheric nitrogen (N deposition requires a better understanding of its influence on the litter decomposition process. This study examines the responses of single-species litter and litter mixture decomposition processes to N addition in Chinese pine (Pinus tabulaeformis Carr. ecosystems. Chinese pine litter, Mongolian oak (Quercus mongolica Fisch. ex Ledeb. litter, and a pine–oak mixture were selected from a plantation and a natural forest of Chinese pine. Four N addition treatments, i.e., control (N0: 0 kg N ha−1·year−1, low-N (N1: 5 kg N ha−1·year−1, medium-N (N2: 10 kg N ha−1·year−1, and high-N (N3: 15 kg N ha−1·year−1, were applied starting May 2010. In the plantation, N addition significantly stimulated the decomposition of the Chinese pine litter. In the natural forest, N addition had variable effects on the decomposition of single-species litter and the litter mixture. A stimulatory effect of the high-N treatment on the Chinese pine litter decomposition could be attributed to a decrease in the substrate C:N ratio. However, an opposite effect was found for the Mongolian oak litter decomposition. The stimulating effect of N addition on the Chinese pine litter may offset the suppressive effect on the Mongolian oak litter, resulting in a neutral effect on the litter mixture. These results suggest that the different responses in decomposition of single-species litter and the litter mixture to N addition are mainly attributed to litter chemical composition. Further investigations are required to characterize the effect of long-term high-level N addition on the litter decomposition as N deposition is likely to increase rapidly in the region where this study was conducted.

  14. Modification of the Kjeldahl noncasein nitrogen method to include bovine milk concentrates and milks from other species.

    Science.gov (United States)

    Wojciechowski, Karen L; Barbano, David M

    2015-11-01

    The objective of our research was to modify the current indirect casein method for bovine milk to enable it to be applied to bovine milk, bovine milk concentrates, and milks of other species that contain a protein concentration up to 9% (wt/wt). Our work used a series of bovine milk concentrates from about 3 to 9% protein with the same casein as a percentage of true protein to determine the amount of buffer required and pH of the noncasein nitrogen (NCN) filtrate to achieve consistent estimates of casein and casein as percent of true protein. As the concentration of protein in milk increased (either in bovine milk concentrates or in milks of other species), the amount of buffer needed for the NCN sample preparation method to achieve a filtrate pH of 4.6 increased. In the first part of the study using a series of bovine milk concentrates, it was demonstrated that the method gave more consistent predictions of casein as a percentage of true protein when the final NCN filtrate pH was between 4.5 and 4.6 at 38°C. When the amount of buffer added to the sample was not sufficient (i.e., the filtrate pH was too high), the filtrates were not clear. A polynomial equation was developed for prediction of the amount of acetic acid or sodium acetate buffer required to achieve pH 4.5 to 4.6 for milk protein concentrations from 3 to 9% protein using bovine milk and milk concentrates. When the equation developed using cow milk was applied to goat, sheep, and water buffalo milks, it correctly predicted the volume of reagents needed to achieve a final NCN filtrate pH of 4.6 at 38°C. We also verified as part of this work that the ability to measure NPN content of milk was not influenced by protein content of milk in the range from 3 to 9% protein. The results of this study will be used as the basis for proposed changes in the official methods for measurement of the casein content of milk to expand the scope of the method so it can be used to achieve accurate results for milk

  15. TORC1 activity is partially reduced under nitrogen starvation conditions in sake yeast Kyokai no. 7, Saccharomyces cerevisiae.

    Science.gov (United States)

    Nakazawa, Nobushige; Sato, Aya; Hosaka, Masahiro

    2016-03-01

    Industrial yeasts are generally unable to sporulate but treatment with the immunosuppressive drug rapamycin restores this ability in a sake yeast strain Kyokai no. 7 (K7), Saccharomyces cerevisiae. This finding suggests that TORC1 is active under sporulation conditions. Here, using a reporter gene assay, Northern and Western blots, we tried to gain insight into how TORC1 function under nitrogen starvation conditions in K7 cells. Similarly to a laboratory strain, RPS26A transcription was repressed and Npr1 was dephosphorylated in K7 cells, indicative of the expected loss of TORC1 function under nitrogen starvation. The expression of nitrogen catabolite repression-sensitive genes, however, was not induced, the level of Cln3 remained constant, and autophagy was more slowly induced than in a laboratory strain, all suggestive of active TORC1. We conclude that TORC1 activity is partially reduced under nitrogen starvation conditions in K7 cells.

  16. Determination of carbon, nitrogen and phosphorus in cattail using cold neutron prompt-gamma activation analysis

    International Nuclear Information System (INIS)

    A method for the determination of carbon, nitrogen, and phosphorus in cattail using cold neutron prompt-gamma activation analysis (CNPGAA) has been developed and evaluated through the analysis of standard reference materials (SRM). After extensive preparation, approximately 400 mg cattail samples from the lower Apalachicola River floodplain were irradiated in the CNPGAA facility at the National Institute of Standards and Technology (NIST). The results of numerous field samples and two standard reference materials using the nuclear method show favorable comparison to results obtained by a CHNS/O analyzer. (author)

  17. Stoichiometric deduction of activated sludge process for organic carbon and nitrogen removal

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-yong; ZOU Lian-pei

    2009-01-01

    The activated sludge process (ASP) is the most generally applied biological wastewater treatment method. The ASP for the removal of organic carbon and nitrogen can be looked as the combination of eight processes. In order to set up an ASP model, the stoichiometric coefficients should be deduced so that the stoichiometric matrix can be presented. The important assumptions and simplifications behind the model for ASP are enumerated. Using the matrix, mass balance equation and consistent units, the stoichiometric coefficients in the eight processes are exclusively deduced one by one.

  18. Anti epileptic activity of ocimum species: A brief review

    Directory of Open Access Journals (Sweden)

    Chhaya Agarwal, N. L. Sharma, S. S. Gaurav

    2013-12-01

    Full Text Available The Ocimum species is a medicinal herb used in the indigenous system of medicine. Ocimum sp. have variety of biological, pharmacological properties such as antibacterial, antiviral, antifungal, antimalarial, anthelmentic, antidiarrhoeal, antiinflammatory, antihypertensive, cardioprotective, central nervous system (CNS depressant, antidiabetic, antithyroidic, antioxidant, anticancer, chemopreventive, radioprotective, immunomodulatory, antifertility, antiulcer, antiarthritic, antistress, antileucodermal and anticoagulant activities. Sevral species of Ocimum are used to cure central nervous system (CNS disorders.in various part of the world due to its anticonvulsant property .epilepsy is a chronic disorder which is characterized by seizures. Seizures are resistant to treatment with currently available anticonvulsant drug (AEDs in about one out of three patient with epilepsy. This review refers to the study of ocimum as an antiepileptic drug (AEDs because of its specific anticonvulsant property.

  19. Phenol Adsorption on Nitrogen-enriched Activated Carbon Prepared from Bamboo Residues

    Directory of Open Access Journals (Sweden)

    Ji Zhang

    2013-12-01

    Full Text Available Nitrogen-enriched activated carbons prepared from bamboo residues were characterized by means of BET, XPS, and elemental analysis. Then adsorption experiments were carried out to study the effects of various physicochemical parameters such as contact time, temperature, pH, and initial concentration. Adsorption equilibrium was achieved within 120 min at a phenol concentration of 250 mg/L. When the pH was 4 and 0.1 g of the carbon absorbent and 100 mL of phenol solution at 250 mg/L were used, the phenol adsorption of the ACs with melamine and urea modifications were 219.09 mg/g and 214.45 mg/g, respectively. Both were greater than the capacity of unmodified AC, which was 163.82 mg/g. The Langmuir isotherm adsorption equation well described the experimental adsorption isotherms. The adsorption kinetics was well explained by pseudo-second-order kinetics rather than the pseudo-first-order. In conclusion, the nitrogen-enriched activated carbon proposed as adsorbents of the phenol wastewater were shown to be effective, which also means that bamboo residues have promise as activated carbon precursors for liquid phase adsorbents for environmental protection.

  20. How nitrogen and sulphur addition, and a single drought event affect root phosphatase activity in Phalaris arundinacea

    NARCIS (Netherlands)

    Robroek, B.J.M.; Adema, E.B.; Venterink, H.O.; Leonardson, L.; Wassen, M.J.

    2009-01-01

    Conservation and restoration of fens and fen meadows often aim to reduce soil nutrients, mainly nitrogen (N) andphosphorus (P). The biogeochemistry of P has received much attention as P-enrichment is expected to negatively impact on species diversity in wetlands. It is known that N, sulphur (S) and

  1. Preparation and characterization of visible-light-active nitrogen-doped TiO2 photocatalyst

    Institute of Scientific and Technical Information of China (English)

    HUANG Xian-huai; TANG Yu-chao; HU Chun; YU Han-qing; CHEN Chu-sheng

    2005-01-01

    A visible-light photocatalyst was prepared by calcination of the hydrolysis product of Ti(SO4 )2 with ammonia as precipitator. The color of this photocatalyst was vivid yellow. It could absorb light under 550 nm wavelength. The crystal structure of anatase was characterized by XRD. The structure analysis result of X-ray fluorescence(XRF) shows that doped-nitrogen was presented in the sample.The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants. The photocatalytic activities of samples were increasing gradually with calcination temperature from 400℃ to 700℃ under UV irradiation. It can be seen that the degradation of methyl orange follows zero-order kinetics. However, the calcination temperatures have no significant influence on the degradation of phenol under sunlight. The N-doped catalyst shows higher activity than the bare one under solar irradiation.

  2. A quantum chemical study for exploring the inhibitory effect of nitrogen containing species on the adsorption of polynuclear aromatic hydrocarbons over a Bronsted acid site

    Science.gov (United States)

    Celis-Cornejo, C. M.; Garnica Mantilla, M. M.; Baldovino-Medrano, V. G.; Ramírez-Caballero, G. E.

    2016-08-01

    The analysis of the inhibitory effect of nitrogenated compounds on the hydroprocessing and hydropurification of oil derived fuels is important to produce cleaner fuels. In this work, density functional theory calculations were performed to investigate the effect of the nitrogen containing molecules on the adsorption of Polynuclear Aromatic Hydrocarbons (PAHs). Mordenite was chosen as a zeolitic structure for simulating a Bronsted acid site. The character of the acid site was confirmed by both a vibrational frequency calculation and a Bader charge analysis. From the adsorption calculations, it was found that the adsorption energy of PAHs increases with the number of aromatic rings in the structure. Also, the nitrogen containing species possibly inhibit more extensively two and three rings PAHs because of their lower adsorption energies. Finally, it was observed that the nitrogen species tend to drag the proton from the mordenite acid site. This explains the inhibitory effect in the adsorption of PAHs and contributes to understanding the dynamics of hydrocarbon hydroprocessing in refineries.

  3. Effect of plasma jet diameter on the efficiency of reactive oxygen and nitrogen species generation in water

    Science.gov (United States)

    Oh, Jun-Seok; Kakuta, Maito; Furuta, Hiroshi; Akatsuka, Hiroshi; Hatta, Akimitsu

    2016-06-01

    The plasma jet generation of reactive oxygen and nitrogen species (RONS) in solution is important in biology, medicine, and disinfection. Studies using a wide variety of plasma jet devices have been carried out for this purpose, making it difficult to compare the performance between devices. In this study, we compared the efficiency of RONS generation in deionized (DI) water between 3.7-mm- and 800-µm-sized helium (He) plasma jets (hereafter mm-jet and µm-jet, respectively) at different treatment distances and times. The efficiency of RONS generation was determined by considering the total amount of RONS generated in DI water with respect to the input energy and gas consumption. We found that the mm-jet generated 20% more RONS in the DI water than the µm-jet at the optimized distance. However, when the input power and He gas consumption were taken into account, we discovered that the µm-jet was 5 times more efficient in generating RONS in the DI water. Under the parameters investigated in this study, the concentration of RONS continued to increase as a function of treatment time (up to 30 min). However treatment distance had a marked effect on the efficiency of RONS generation: treatment distances of 25 and 30 mm were optimal for the mm-jet and µm-jet, respectively. Our method of comparing the efficiency of RONS generation in solution between plasma jets could be used as a reference protocol for the development of efficient plasma jet sources for use in medicine, biology, and agriculture.

  4. Imbalances in faecal and duodenal Bifidobacterium species composition in active and non-active coeliac disease

    Directory of Open Access Journals (Sweden)

    Sanz Yolanda

    2008-12-01

    Full Text Available Abstract Background Gut bifidobacteria are believed to influence immune-related diseases. The objective of this study was to assess the possible relationships between the gut bifidobacteria composition and coeliac disease (CD in children. A total of 48 faecal samples (30 and 18 samples from active and no active CD patients, respectively and 33 duodenal biopsy specimens of CD patients (25 and 8 samples from active and non-active CD patients, respectively were analysed. Samples (30 faecal samples and 8 biopsies from a control age-matched group of children were also included for comparative purposes. Gut Bifidobacterium genus and species were analyzed by real-time PCR. Results Active and non-active CD patients showed lower numbers of total Bifidobacterium and B. longum species in faeces and duodenal biopsies than controls, and these differences were particularly remarkable between active CD patients and controls. B. catenulatum prevalence was higher in biopsies of controls than in those of active and non-active CD patients, whereas B. dentium prevalence was higher in faeces of non-active CD patients than in controls. Correlations between levels of Bifidobacterium and B. longum species in faecal and biopsy samples were detected in both CD patients and controls. Conclusion Reductions in total Bifidobacterium and B. longum populations were associated with both active and non-active CD when compared to controls. These bacterial groups could constitute novel targets for adjuvant dietary therapies although the confirmation of this hypothesis would require further investigations.

  5. Lectin activity in mycelial extracts of Fusarium species.

    Science.gov (United States)

    Bhari, Ranjeeta; Kaur, Bhawanpreet; Singh, Ram S

    2016-01-01

    Lectins are non-immunogenic carbohydrate-recognizing proteins that bind to glycoproteins, glycolipids, or polysaccharides with high affinity and exhibit remarkable ability to agglutinate erythrocytes and other cells. In the present study, ten Fusarium species previously not explored for lectins were screened for the presence of lectin activity. Mycelial extracts of F. fujikuroi, F. beomiformii, F. begoniae, F. nisikadoi, F. anthophilum, F. incarnatum, and F. tabacinum manifested agglutination of rabbit erythrocytes. Neuraminidase treatment of rabbit erythrocytes increased lectin titers of F. nisikadoi and F. tabacinum extracts, whereas the protease treatment resulted in a significant decline in agglutination by most of the lectins. Results of hapten inhibition studies demonstrated unique carbohydrate specificity of Fusarium lectins toward O-acetyl sialic acids. Activity of the majority of Fusarium lectins exhibited binding affinity to d-ribose, l-fucose, d-glucose, l-arabinose, d-mannitol, d-galactosamine hydrochloride, d-galacturonic acid, N-acetyl-d-galactosamine, N-acetyl-neuraminic acid, 2-deoxy-d-ribose, fetuin, asialofetuin, and bovine submaxillary mucin. Melibiose and N-glycolyl neuraminic acid did not inhibit the activity of any of the Fusarium lectins. Mycelial extracts of F. begoniae, F. nisikadoi, F. anthophilum, and F. incarnatum interacted with most of the carbohydrates tested. F. fujikuroi and F. anthophilum extracts displayed strong interaction with starch. The expression of lectin activity as a function of culture age was investigated. Most species displayed lectin activity on the 7th day of cultivation, and it varied with progressing of culture age. PMID:27237111

  6. Thermodynamic Model for Calculating Activity of Nitrogen and Boron in Fe-C-B-N Molten Metal

    Institute of Scientific and Technical Information of China (English)

    WANG Shi-jun; PENG Jun; DONG Yuan-chi; LIU Li-xia; ZHOU Yun; CHEN Er-bao

    2009-01-01

    The solubility of nitrogen in Fe-C-B-N system was measured at 1 758 K,and the computational model on activity (action concentration) of nitrogen and boron was established based on phase diagram and the coexistence theory about metal melt structure model.Comparing the computed results with the experimental results,satisfactory conclusion can be obtained.The result shows that BN and B4C can exist in Fe-C-B-N molten metal at high temperature,which consequently restrains the nitrogen removal from the melt.However,B4C content is extremely low.Before graphite is precipitated,the influence of carbon on activity of nitrogen in melt is higher in ternary system than in binary system; however,this effect is contrary to that after graphite is precipitated.

  7. Effects of nitrogen- and oxygen-containing functional groups of activated carbon nanotubes on the electrochemical performance in supercapacitors

    Science.gov (United States)

    Liu, Haiyan; Song, Huaihe; Chen, Xiaohong; Zhang, Su; Zhou, Jisheng; Ma, Zhaokun

    2015-07-01

    A kind of nitrogen- and oxygen-containing activated carbon nanotubes (ACNTs) has been prepared by carbonization and activation of polyaniline nanotubes obtained by rapidly mixed reaction. The ACNTs show oxygen content of 15.7% and nitrogen content of 2.97% (atomic ratio). The ACNTs perform high capacitance and good rate capability (327 F g-1 at the current density of 10 A g-1) when used as the electrode materials for supercapacitors. Hydrogen reduction has been further used to investigate the effects of surface functional groups on the electrochemical performance. The changes for both structural component and electrochemical performance reveal that the quinone oxygen, pyridinic nitrogen, and pyrrolic nitrogen of carbon have the most obvious influence on the capacitive property because of their pseudocapacitive contributions.

  8. Differential activity of innate defense antimicrobial peptides against Nocardia species

    Directory of Open Access Journals (Sweden)

    Wagner Dirk

    2010-02-01

    Full Text Available Abstract Background Members of the genus Nocardia are ubiquitous environmental saprophytes capable to cause human pulmonary, disseminated and cutaneous nocardiosis or bovine mastitis. Innate immunity appears to play an important role in early defense against Nocardia species. To elucidate the contribution of antimicrobial peptides (AMPs in innate defense against Nocardia, the activity of human α-defensins human neutrophil peptides (HNPs 1-3, human β-defensin (hBD-3 and cathelicidin LL-37 as well as bovine β-defensins lingual and tracheal antimicrobial peptides (LAP, TAP and bovine neutrophil-derived indolicidin against four important Nocardia species was investigated. Results Whereas N. farcinica ATCC 3318 and N. nova ATCC 33726 were found to be susceptible to all investigated human and bovine AMPs, N. asteroides ATCC 19247 was killed exclusively by neutrophil-derived human α-defensins HNP 1-3 and bovine indolicidin. N. brasiliensis ATCC 19296 was found to exhibit complete resistance to investigated human AMPs and to be susceptible only to bovine indolicidin. Conclusion Selected AMPs are capable to contribute to the first line of defense against Nocardia, yet, susceptibility appears to vary across different Nocardia species. Obtained results of neutrophil-derived AMPs to possess the broadest antinocardial spectrum are remarkable, since nocardiosis is characterized by a neutrophil-rich infiltrate in vivo.

  9. Distribution of trace elements in organs of six species of cetaceans from the Ligurian Sea (Mediterranean), and the relationship with stable carbon and nitrogen ratios

    OpenAIRE

    Capelli, R.; Das, Krishna; Pellegrini, R.; Drava, G.; Lepoint, Gilles; Miglio, Cristiana; Minganti, V.; R. Poggi

    2008-01-01

    Mercury (total and organic), cadmium, lead, copper, iron, manganese, selenium and zinc concentrations were measured in different organs of 6 different cetacean species stranded in an area of extraordinary ecological interest (Cetaceans' Sanctuary of the Mediterranean Sea) along the coast of the Ligurian Sea (North-West Mediterranean). Stable-isotopes ratios of carbon (13C/12C) and nitrogen (15N/14N) were also measured in the muscle. A significant relationship exists between 15N/14N, mercury c...

  10. Stability of above-ground and below-ground processes to extreme drought in model grassland ecosystems: Interactions with plant species diversity and soil nitrogen availability.

    OpenAIRE

    Bloor, Juliette; Bardgett, R. D.

    2012-01-01

    Extreme drought events have the potential to cause dramatic changes in ecosystem structure and function, but the controls upon ecosystem stability to drought remain poorly understood. Here we used model systems of two commonly occurring, temperate grassland communities to investigate the shortterm interactive effects of a simulated 100-year summer drought event, soil nitrogen (N) availability and plant species diversity (low/high) on key ecosystem processes related to carbon (C) and N cycling...

  11. Purification and in vitro activities of the native nitrogen fixation control proteins NifA and NifL.

    OpenAIRE

    Austin, S; Buck, M; Cannon, W; Eydmann, T.; Dixon, R

    1994-01-01

    The prokaryotic enhancer-binding protein NifA stimulates transcription at a distance by binding to sequences upstream of nitrogen fixation (nif) promoters and catalyzing the formation of open promoter complexes by RNA polymerase containing the alternative sigma factor, sigma 54. The activity of NifA in vivo is modulated by the negative regulatory protein NifL in response to environmental oxygen and fixed nitrogen. To date, a detailed biochemical analysis of these proteins from the model diazo...

  12. Nitrogen and carbohydrate fractions in exclusive Tifton 85 and in pasture oversown with annual winter forage species - 10.4025/actascianimsci.v34i1.11428

    Directory of Open Access Journals (Sweden)

    Ana Claudia Ruggieri

    2011-11-01

    Full Text Available The experiment was undertaken at the Faculty of Agrarian and Veterinary Sciences (FCAV Jaboticabal, São Paulo State, Brazil, during winter-spring-summer of 2001-2002, to determine the fractionation of nitrogen and carbohydrates in Tifton 85 (Cynodon dactylon Vanderyst x Cynodon nlemfuensis (L. Pers, exclusively or oversown with winter annual forage species. Treatments comprised bristle oat (Avena strigosa Schreb, yellow oat (Avena byzantina C. Koch, triticale (X Triticosecale Wittmack, bristle oat + yellow oat, bristle oat + triticale, yellow oat + triticale, bristle oat + yellow oat + triticale seeded in Tifton 85 and sole crop (control. Experimental design was composed of completely randomized blocks with three replications. Fodder was cut 20 cm high (presence of winter forage and 10 cm high (Tifton 85 pasture. Crude protein, total carbohydrate and the fractions of nitrogen compounds and carbohydrates were determined. Decrease was reported in the levels of chemical compounds in winter forage species and in Tifton 85 during the evaluation periods. The content of nitrogen compounds and carbohydrates varied widely during the evaluation period according to the morphological characteristics of grass species and botanical composition of pastures.

  13. Antifungal activity of heartwood extracts from three Juniperus species

    Directory of Open Access Journals (Sweden)

    Ibrahim Tumen

    2013-02-01

    Full Text Available Heartwood samples from three species of Juniperus (i.e., J. virginiana, J. occidentalis, and J. ashei were extracted with hexane, ethanol, and methanol. The hexane and ethanol extracts were tested for antifungal activity against four species of wood-rot fungi (i.e, Gloeophyllum trabeum, Postia placenta, Trametes versicolor, and Irpex lacteus. Ashe juniper (AJ gave the highest extract yields (6.60 to 11.27%, followed by Eastern red cedar (ERC (4.78 to 9.56%, and then Western juniper (WJ (4.26 to 7.32%. WJ contained the highest level of cedrol (over 60%, while AJ contained the highest level of thujopsene (over 30%. Methanol and ethanol gave the highest extract yields as well as slightly higher percentages of cedrol and widdrol. The juniper extracts were more effective against white-rot fungi than brown-rot fungi. The ethanol extracts had higher antifungal activity than the hexane extracts. The AJ extracts had the greatest bioactivity against the wood-rot fungi.

  14. Antimicrobial activity of Amazonian oils against Paenibacillus species.

    Science.gov (United States)

    Santos, Roberto Christ Vianna; dos Santos Alves, Camilla Filippi; Schneider, Taiane; Lopes, Leonardo Quintana Soares; Aurich, Carlos; Giongo, Janice Luehring; Brandelli, Adriano; de Almeida Vaucher, Rodrigo

    2012-03-01

    The Gram-positive, spore-forming bacterium Paenibacillus larvae is the primary bacterial pathogen of honeybee brood and the causative agent of American foulbrood disease (AFB). One of the feasible alternative treatments being used for their control of this disease is essential oils. In this study in vitro antimicrobial activity of Andiroba and Copaíba essential oils against Paenibacillus species, including P. larvae was evaluated. Minimal inhibitory concentration (MIC) in Mueller-Hinton broth by the microdilution method was assessed. Andiroba registered MIC values of 1.56-25%, while the MICs values obtained for Copaíba oil were of 1.56-12.5%. In order to determine the time-response effect of essential oils on P. larvae, this microorganism was exposed to the oils for up to 48 h. After 24 h treatment with Andiroba oil and after 48 h treatment with Copaíba oil no viable cells of P. larvae ATCC 9545 were observed. The possible toxic effect of essential oils were assessed by the spraying application method of the same concentrations of MICs. Bee mortality was evident only in treatment with Andiroba oil and the Copaíba oil shows no toxic effects after 10 days of observation. Taking together ours results showed for the first time that these oils presented a high activity against Paenibacillus species showing that Copaíba oil may be a candidate for the treatment or prevention of AFB. PMID:22200645

  15. Combined effect of nitrogen- and oxygen-containing functional groups of microporous activated carbon on its electrochemical performance in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Hulicova-Jurcakova, Denisa; Lu, Gao Qing [University of Queensland ARC, Centre of Excellence for Functional Nanomaterials Australian Institute for Bioengineering and Nanotechnology and School of Engineering Corner College, St Lucia (Australia); Seredych, Mykola; Bandosz, Teresa J. [City College of New York, Department of Chemistry, New York, NY (United States)

    2009-02-10

    Microporous activated carbon originating from coconut shell, as received or oxidized with nitric acid, is treated with melamine and urea and heated to 950 C in an inert atmosphere to modify the carbon surface with nitrogen- and oxygen-containing groups for a systematic investigation of their combined effect on electrochemical performance in 1 M H{sub 2}SO{sub 4} supercapacitors. The chemistry of the samples is characterized using elemental analysis, Boehm titration, potentiometric titration, and X-ray photoelectron spectroscopy. Sorption of nitrogen and carbon dioxide is used to determine the textural properties. The results show that the surface chemistry is affected by the type of nitrogen precursor and the specific groups present on the surface before the treatment leading to the incorporation of nitrogen. Analysis of the electrochemical behavior of urea- and melamine-treated samples reveal pseudocapacitance from both the oxygen and the nitrogen containing functional groups located in the pores larger than 10A. On the other hand, pores between 5A and 6A are most effective in a double-layer formation, which correlates well with the size of hydrated ions. Although the quaternary and pyridinic-N-oxides nitrogen groups have enhancing effects on capacitance due to the positive charge, and thus an improved electron transfer at high current loads, the most important functional groups affecting energy storage performance are pyrrolic and pyridinic nitrogen along with quinone oxygen. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  16. Synthesis and enhancement of visible light activities of nitrogen-doped BaTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Jiafeng, E-mail: cjf786@163.com [School of Mathematics and Physics, Anhui University of Technology, Maanshan, Anhui 243002 (China); Ji, Yuexia [School of Mathematics and Physics, Anhui University of Technology, Maanshan, Anhui 243002 (China); Tian, Chongbin; Yi, Zhiguo [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2014-12-05

    Highlights: • N-doped BaTiO{sub 3} photocatalyst was synthesized by urea addition solid state synthesis. • N-doped BaTiO{sub 3} shows improved photocatalytic activity irradiated by visible light. • Nitrogen dopant and oxygen vacancy are the main factors that enhance the activities. - Abstract: Regular nitrogen-doped BaTiO{sub 3} particles were synthesized by urea addition solid state sintering method. Compared with the undoped samples, the N-doped photocatalyst shows improved activities of photodegradation to Rhodamine-B under visible light irradiation (420 nm < λ < 780 nm). The obviously increased performance of N-doped BaTiO{sub 3} is mainly ascribed to the broadening of valence band (VB) width. Based on the analysis of absorption spectra and the illustration of photocatalytic role for N-doped BaTiO{sub 3}, nitrogen dopants and oxygen vacancies are both responsible for the improved photocatalytic activities.

  17. Long-term nitrogen addition leads to loss of species richness due to litter accumulation and soil acidification in a temperate steppe.

    Directory of Open Access Journals (Sweden)

    Ying Fang

    Full Text Available BACKGROUND: Although community structure and species richness are known to respond to nitrogen fertilization dramatically, little is known about the mechanisms underlying specific species replacement and richness loss. In an experiment in semiarid temperate steppe of China, manipulative N addition with five treatments was conducted to evaluate the effect of N addition on the community structure and species richness. METHODOLOGY/PRINCIPAL FINDINGS: Species richness and biomass of community in each plot were investigated in a randomly selected quadrat. Root element, available and total phosphorus (AP, TP in rhizospheric soil, and soil moisture, pH, AP, TP and inorganic N in the soil were measured. The relationship between species richness and the measured factors was analyzed using bivariate correlations and stepwise multiple linear regressions. The two dominant species, a shrub Artemisia frigida and a grass Stipa krylovii, responded differently to N addition such that the former was gradually replaced by the latter. S. krylovii and A. frigida had highly-branched fibrous and un-branched tap root systems, respectively. S. krylovii had higher height than A. frigida in both control and N added plots. These differences may contribute to the observed species replacement. In addition, the analysis on root element and AP contents in rhizospheric soil suggests that different calcium acquisition strategies, and phosphorus and sodium responses of the two species may account for the replacement. Species richness was significantly reduced along the five N addition levels. Our results revealed a significant relationship between species richness and soil pH, litter amount, soil moisture, AP concentration and inorganic N concentration. CONCLUSIONS/SIGNIFICANCE: Our results indicate that litter accumulation and soil acidification accounted for 52.3% and 43.3% of the variation in species richness, respectively. These findings would advance our knowledge on the

  18. Defect induced nickel, nitrogen-codoped mesoporous TiO2 microspheres with enhanced visible light photocatalytic activity

    Science.gov (United States)

    Zou, Mingming; Feng, Lu; Ganeshraja, Ayyakannu Sundaram; Xiong, Fengqiang; Yang, Minghui

    2016-10-01

    Nickel, nitrogen-codoped mesoporous TiO2 microspheres (Ni-N-TiO2) with high surface area, and an effective direct band gap energy of ∼2.58 eV. Nickel sulfate used as the Ni source and ammonia gas as the N source here. The efficiency of the as-prepared samples was investigated by monitoring the degradation of Rhodamine B under visible light irradiation. The experimental results indicate that Ni-doped mesoporous TiO2 microspheres show higher photocatalytic activity than mesoporous TiO2 microspheres under visible light irradiation. It mainly due to that the electron trap level (Ni2+/Ni+) promoting the separation of charge carriers and the oxygen vacancies inducing the visible light absorption. In addition, Ni-N-TiO2 shows enhanced activity compared with Ni-TiO2. Codopants and dopants are found to be uniformly distributed in TiO2 matrix. Among the all samples the 0.5% molar quantity of Ni dopant and 500 °C 2 h nitriding condition gives the highest photocatalytic activity. The treatment of ammonia gas on Ni-TiO2 sample induced oxygen vancancies, substitutional and interstitial N. A suitable treatment by ammonia gas also promote separation of charge carriers and the absorption of visible light. The active species generated in the photocatalytic system were also investigated. The strategy presented here gives a promising route towards the development of a metal and non-metal codoped semiconductor materials for applied photocatalysis and related applications.

  19. Alkaloid profiling and anticholinesterase activity of South American Lycopodiaceae species.

    Science.gov (United States)

    Konrath, Eduardo Luis; Ortega, María Gabriela; de Loreto Bordignon, Sérgio; Apel, Miriam Anders; Henriques, Amélia Teresinha; Cabrera, José Luis

    2013-02-01

    The alkaloid extracts of four Huperzia and one Lycopodiella species, from Brazilian habitats, were tested for their in vitro anticholinesterase activities. IC(50) values showed a potent acetylcholinesterase inhibition for H. reflexa (0.11 ± 0.05 μg/mL), followed by H. quadrifariata (2.0 ± 0.3 μg/mL), H. acerosa (5.5 ± 0.9 μg/mL), H. heterocarpon (25.6 ± 2.7 μg/mL) and L. cernua (42.6 ± 1.5 μg/mL). A lower inhibition of butyrylcholinesterase was observed for all species with the exception of H. heterocarpon (8.3 ± 0.9 μg/mL), whose alkaloid extract presented a selectivity for pseudocholinesterase. Moreover, the chemical study of the bioactive extracts performed by GC-MS, revealed the presence of a number of Lycopodium alkaloids belonging to the lycopodane, flabellidane and cernuane groups. Surprisingly, the potent acetylcholinesterase inhibitors huperzines A and B were not detected in the extracts, suggesting that other alkaloids may be responsible for such an effect. PMID:22117191

  20. Measurements of Nitric Acid and Aerosol Species Aboard the NASA DC-8 Aircraft During the SASS Ozone and Nitrogen Oxide Experiment (SONEX)

    Science.gov (United States)

    Talbot, Robert W.; Dibb, Jack E.

    1999-01-01

    The SASS Ozone and Nitrogen Oxides Experiment (SONEX) over the North Atlantic during October/November 1997 offered an excellent opportunity to examine the budget of total reactive nitrogen (NO(sub y)) in the upper troposphere (8 - 12 km altitude). The median measured NO(sub y) mixing ratio was 425 parts per trillion by volume (pptv). Two different methods were used to measure HNO3: (1) the mist chamber technique and, (2) chemical ionization mass spectrometry. Two merged data sets using these HNO3 measurements were used to calculate NO(sub y) by summing the reactive nitrogen species (a combination of measured plus modeled results) and comparing the resultant values to measured NO(sub y) (gold catalytic reduction method). Both comparisons showed good agreement in the two quantities (slope > 0.9 and r(exp 2) > 0.9). Thus, the total reactive nitrogen budget in the upper troposphere over the North Atlantic can be explained in a general manner as a simple mixture of NO(sub x). (NO + NO2), HNO3, and PAN. Median values of NO(sub x)/NO(sub y) were approximately equal to 0.25, HNO3/NO(sub y) were approximately equal to 0.35 and Peroxyacetyl Nitrate (PAN)/NO(sub y) were approximately equal to 0. 17. Particulate NO3 and alkyl nitrates together composed <10 % of NO(sub y), while model estimated HNO4 averaged 12%.

  1. Raman Optical Activity and Raman Spectra of Amphetamine Species

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Shim, Irene; White, Peter Cyril;

    2012-01-01

    Theoretical calculations and preliminary measurements of vibrational Raman optical activity (ROA) spectra of different species of amphetamine (amphetamine and amphetamine-H+) are reported for the first time. The quantum chemical calculations were carried out as hybrid ab initio DFT......-molecular orbital calculations by use of the Gaussian 03W pro- gram, based on complete geometry minimizations of the conformational energy of the S-(+)-amphetamine molecule, the S-(+)-amphetamine-H+ ion, and the R-(–)-amphetamine molecule. Following this, harmonic frequency calculations have been made, providing...... are employed for identification purposes. The DFT calculations show that the most stable conformations are those allowing for close contact between the aromatic ring and the amine hydrogen atoms. The internal rotational barrier within the same amphetamine enanti- omer has a considerable influence on the Raman...

  2. One molecule, many derivatives: a never-ending interaction of melatonin with reactive oxygen and nitrogen species?

    Science.gov (United States)

    Tan, Dun-Xian; Manchester, Lucien C; Terron, Maria P; Flores, Luis J; Reiter, Russel J

    2007-01-01

    Melatonin is a highly conserved molecule. Its presence can be traced back to ancient photosynthetic prokaryotes. A primitive and primary function of melatonin is that it acts as a receptor-independent free radical scavenger and a broad-spectrum antioxidant. The receptor-dependent functions of melatonin were subsequently acquired during evolution. In the current review, we focus on melatonin metabolism which includes the synthetic rate-limiting enzymes, synthetic sites, potential regulatory mechanisms, bioavailability in humans, mechanisms of breakdown and functions of its metabolites. Recent evidence indicates that the original melatonin metabolite may be N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) rather than its commonly measured urinary excretory product 6-hydroxymelatonin sulfate. Numerous pathways for AFMK formation have been identified both in vitro and in vivo. These include enzymatic and pseudo-enzymatic pathways, interactions with reactive oxygen species (ROS)/reactive nitrogen species (RNS) and with ultraviolet irradiation. AFMK is present in mammals including humans, and is the only detectable melatonin metabolite in unicellular organisms and metazoans. 6-hydroxymelatonin sulfate has not been observed in these low evolutionary-ranked organisms. This implies that AFMK evolved earlier in evolution than 6-hydroxymelatonin sulfate as a melatonin metabolite. Via the AFMK pathway, a single melatonin molecule is reported to scavenge up to 10 ROS/RNS. That the free radical scavenging capacity of melatonin extends to its secondary, tertiary and quaternary metabolites is now documented. It appears that melatonin's interaction with ROS/RNS is a prolonged process that involves many of its derivatives. The process by which melatonin and its metabolites successively scavenge ROS/RNS is referred as the free radical scavenging cascade. This cascade reaction is a novel property of melatonin and explains how it differs from other conventional antioxidants. This cascade

  3. Nitrogen and carbohydrate fractions on Tifton-85 pastures overseeded with annual winter and summer forage species in different seasons

    Directory of Open Access Journals (Sweden)

    Andréia Luciane Moreira

    2012-09-01

    Full Text Available An experiment was conducted during the 2001-2002 winter-spring-summer to determine the nitrogen and carbohydrate fractions in Tifton-85 pastures exclusively or overseeded with oats, millet and sorghum-sudangrass hybrids. The treatments were Tifton-85 overseeded with millet + bristle oat; sorghum-sudangrass + bristle oat, on 06/19/2002 and 07/02/2002, respectively; and Tifton-85 (Control. The experiment was conducted in a randomized block design with three replications. Nitrogen and carbohydrate fractions were affected by the nitrogen and total carbohydrate contents observed in the pasture overseeded at different seeding times, and by the different growth periods. The highest nitrogen fractions (A + B1 were observed in the early growth periods. Overseeding affected the forage nitrogen and carbohydrate fraction contents positively. The high solubility of both carbohydrate and protein from millet + bristle oat and bristle oat + sorghum-sudangrass mixtures indicates the quality of these forages and their potential use as an important supplement in forage systems based on tropical pastures.

  4. Soil carbon and nitrogen dynamics linked to Piliostigma species in ferugino-tropical soils in the Sudano-Sahelian zone of Burkina Faso,West Africa

    Institute of Scientific and Technical Information of China (English)

    Barthélémy Yélémou; Sidzabda Djibril Dayamba; Dasmane Bambara; Georges Yaméogo; Salawu Assimi

    2013-01-01

    In the Sudano-Sahelian zone of Burkina Faso,Piliostigma reticulatum (DC) Hochst and Piliostigma thonningii (Schumach) are precursor species of fallow land colonization and they are used by rural villagers.The present study aimed to assess the contribution of Piliostigma species to soil quality improvement.We quantified organic carbon,total nitrogen,soil microbial biomass,soil basal respiration and metabolic quotient from soil samples taken under and outside Piliostigma canopies.We used one-way ANOVA to test for differences in the above parameters between locations (beneath and outside Piliostigma canopies).We recorded increased total organic carbon under Piliostigma from 31%-105% and in total nitrogen from 23%-66%.Microbial biomass was 13%-266% higher beneath canopies as compared to outside canopies.Basal respiration was also higher beneath canopies.The chemical elements varied by class of soil texture.Metabolic quotient (qCO2) was significantly correlated to clay (r =0.80) and silt (r =0.79) content.Piliostigma stands produced abundant litter due to their leaf biomass.Thus,they contribute to improved total organic carbon and total nitrogen content in the different phytogeographic zones and improve soil fertility

  5. Nitrogen fixation associated with development and localization of mixed populations of Cellulomonas species and Azospirillium brasilense grown on cellulose or wheat straw

    Energy Technology Data Exchange (ETDEWEB)

    Halsall, D.M.; Goodchild, D.J.

    1986-04-01

    Mixed cultures of Cellulomonas sp. and Azospirillum brasilense were grown with straw or cellulose as the carbon source under conditions favoring the fixation of atmospheric nitrogen. Rapid increases in cell numbers, up to 10/sup 9/ cells per g of substrate, were evident after 4 and 5 days of incubation at 30 degrees C for cellulose and straw, respectively. Nitrogen fixation (detected by acetylene reduction measured on parallel cultures) commenced after 2 and 4 days of incubation for straw and cellulose, respectively, and continued for the duration of the experiment. Pure cultures of Cellulomonas sp. showed an increase in cell numbers, but CO/sub 2/ production was low, and acetylene reduction was not detected on either cellulose or straw. Pure cultures of A. brasilense on cellulose showed an inital increase in cell numbers (10/sup 7/ cells per g of substrate) over 4 days, followed by a decline presumably caused by the exhaustion of available carbon substrate. On straw, A. brasilense increased to 10/sup 9/ cells per g of substrate over 5 days and then declined slowly; this growth was accompanied by acetylene reduction. Scanning electron micrographs of straw incubated with a mixture under the above conditions for 8 days showed cells of both species in close proximity to each other. Evidence was furnished that the close spatial relatioship of cells from the two species facilitated the mutally beneficial association between them and thus increased the efficiency with which the products of straw breakdown were used for nitrogen fixation. 17 references.

  6. Thermal activation of nitrogen acceptors in ZnO thin films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Dangbegnon, J.K.; Talla, K.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth (South Africa)

    2010-06-15

    Nitrogen doping in ZnO is inhibited by spontaneous formation of compensating defects. Perfect control of the nitrogen doping concentration is required, since a high concentration of nitrogen could induce the formation of donor defects involving nitrogen. In this work, the effect of post-growth annealing in oxygen ambient on ZnO thin films grown by Metalorganic Chemical Vapor Deposition, using NO as both oxidant and nitrogen dopant, is studied. After annealing at 700 C and above, low-temperature photoluminescence shows the appearance of a transition at {proportional_to}3.23 eV which is interpreted as pair emission involving a nitrogen acceptor. A second transition at {proportional_to}3.15 eV is also discussed. This work suggests annealing as a potential means for p-type doping using nitrogen (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Coupled hydrological and biogeochemical processes controlling variability of nitrogen species in streamflow during autumn in an upland forest

    Science.gov (United States)

    Sebestyen, Stephen D.; Shanley, James B.; Boyer, Elizabeth W.; Kendall, Carol; Doctor, Daniel H.

    2014-02-01

    Autumn is a season of dynamic change in forest streams of the northeastern United States due to effects of leaf fall on both hydrology and biogeochemistry. Few studies have explored how interactions of biogeochemical transformations, various nitrogen sources, and catchment flow paths affect stream nitrogen variation during autumn. To provide more information on this critical period, we studied (1) the timing, duration, and magnitude of changes to stream nitrate, dissolved organic nitrogen (DON), and ammonium concentrations; (2) changes in nitrate sources and cycling; and (3) source areas of the landscape that most influence stream nitrogen. We collected samples at higher temporal resolution for a longer duration than typical studies of stream nitrogen during autumn. This sampling scheme encompassed the patterns and extremes that occurred during base flow and stormflow events of autumn. Base flow nitrate concentrations decreased by an order of magnitude from 5.4 to 0.7 µmol L-1 during the week when most leaves fell from deciduous trees. Changes to rates of biogeochemical transformations during autumn base flow explained the low nitrate concentrations; in-stream transformations retained up to 72% of the nitrate that entered a stream reach. A decrease of in-stream nitrification coupled with heterotrophic nitrate cycling were primary factors in the seasonal nitrate decline. The period of low nitrate concentrations ended with a storm event in which stream nitrate concentrations increased by 25-fold. In the ensuing weeks, peak stormflow nitrate concentrations progressively decreased over closely spaced, yet similarly sized events. Most stormflow nitrate originated from nitrification in near-stream areas with occasional, large inputs of unprocessed atmospheric nitrate, which has rarely been reported for nonsnowmelt events. A maximum input of 33% unprocessed atmospheric nitrate to the stream occurred during one event. Large inputs of unprocessed atmospheric nitrate show

  8. Influence of diet and microbial activity in the digestive tract on digestibility, and nitrogen and energy metabolism in rats and pigs

    DEFF Research Database (Denmark)

    Eggum, B O; Thorbek, G; Beames, R M;

    1982-01-01

    1. Balance trials with respiration measurements were performed with twelve rats and twelve pigs given either low- or high-crude-fibre diets. There were six collection periods with the rats over a live-weight range of 86-264 g and three collection periods with the pigs over a live-weight range of 30......-55 kg. Measurements were made on the influence of microbial activity in the digestive tract on digestibility and nitrogen and energy metabolism. Dietary inclusion of the antibiotic Nebacitin was the method used to reduce the microbial population. 2. The microbial activity in the hind-gut (mumol ATP....../g air-dry contents) of antibiotic-treated rats was reduced to approximately one-tenth of that of untreated rats. 3. Live-weight gain was not significantly affected in either species by a reduction in the microbial activity, in spite of a reduction in dry matter digestibility in animals with reduced...

  9. Complete Genome sequence of Burkholderia phymatum STM815, a broad host range and efficient nitrogen-fixing symbiont of Mimosa species

    Energy Technology Data Exchange (ETDEWEB)

    Moulin, Lionel [UMR, France; Klonowska, Agnieszka [UMR, France; Caroline, Bournaud [UMR, France; Booth, Kristina [University of Massachusetts; Vriezen, Jan A.C. [University of Massachusetts; Melkonian, Remy [UMR, France; James, Euan [James Hutton Institute, Dundee, United Kingdom; Young, Peter W. [University of York, United Kingdom; Bena, Gilles [UMR, France; Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Bruce, David [Los Alamos National Laboratory (LANL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Copeland, A [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Lizotte-Waniewski, Michelle [University of Massachusetts; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Riley, Monica [Woods Hole Oceanographic Institution (WHOI), Woods Hole

    2014-01-01

    Burkholderia phymatum is a soil bacterium able to develop a nitrogen-fixing symbiosis with species of the legume genus Mimosa, and is frequently found associated specifically with Mimosa pudica. The type strain of the species, STM 815T, was isolated from a root nodule in French Guiana in 2000. The strain is an aerobic, motile, non-spore forming, Gram-negative rod, and is a highly competitive strain for nodulation compared to other Mimosa symbionts, as it also nodulates a broad range of other legume genera and species. The 8,676,562 bp genome is composed of two chromosomes (3,479,187 and 2,697,374 bp), a megaplasmid (1,904,893 bp) and a plasmid hosting the symbiotic functions (595,108 bp).

  10. Anthelmintic activity of the latex of Ficus species.

    Science.gov (United States)

    de Amorin, A; Borba, H R; Carauta, J P; Lopes, D; Kaplan, M A

    1999-03-01

    The latex of some species of Ficus (Moraceae) has been traditionally used as vermifuge in Central and South America. It has been accepted that anthelmintic activity is due to a proteolytic fraction called ficin. In the present study, the anthelmintic activity of the latex of Ficus insipida Willd. and Ficus carica L. has been investigated in NIH mice naturally infected with Syphacia obvelata, Aspiculuris tetraptera and Vampirolepis nana. The latex of F. insipida, administered by intragastric route in doses of 4 ml/kg/day during three consecutive days, were effective in the removal of 38.6% of the total number of S. obvelata, being inexpressive in the removal of A. tetraptera (8.4%) and segments of V. nana (6.3%). The latex of F. carica, administered in doses of 3 ml/kg/day, during three consecutive days, was effective in the removal of S. obvelata (41.7%) and it did not produce significant elimination of A. tetraptera (2.6%) and V. nana (8.3%). The observed high acute toxicity with hemorrhagic enteritis, in addition to a weak anthelmintic efficacy, do not recommend the use of these lattices in traditional medicine.

  11. Photosynthesis acclimation, leaf nitrogen concentration, and growth of four tree species over 3 years in response to elevated carbon dioxide and nitrogen treatment in subtropical China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juxiu; Zhou, Guoyi; Duan, Honglang; Li, Yuelin; Zhang, Deqiang [Chinese Academy of Sciences, Guangzhou (China). South China Botanical Garden; Xu, Zhihong [Griffith Univ., Nathan, Brisbane (Australia). Centre for Forestry and Horticultural Research

    2011-10-15

    Up to date, most studies about the plant photosynthetic acclimation responses to elevated carbon dioxide (CO{sub 2}) concentration have been performed in temperate areas, which are often N limited under natural conditions and with low ambient N deposition. It is unclear whether photosynthetic downregulation is alleviated with increased N availability, for example, from increased N deposition due to fossil fuel combustion in the tropics and subtropics. Awareness of plant photosynthetic responses to elevated CO{sub 2} concentration will contribute to the better understanding and prediction of future forest productivity under global change. Four tree species, Schima superba Gardn. et Champ., Ormosia pinnata (Lour.) Merr, Castanopsis hystrix AC. DC., and Acmena acuminatissima (Blume) Merr. et Perry were exposed to a factorial combination of atmospheric CO{sub 2} concentration (ambient and elevated CO{sub 2} concentration at ca. 700 {mu}mol CO{sub 2} mol{sup -1}) and N deposition (ambient and ambient + 100 kg N ha{sup -1} year{sup -1}) in open-top chambers in southern China for 3 years since March 2005. Light-saturated net photosynthetic rate, leaf N concentration, and tree growth of all species were measured. The CO{sub 2} treatments did not affect light-saturated net photosynthetic rate of all species grown with the high N treatment. However, S. superba grown with the low N treatment (ambient) had 23% and 47% greater net photosynthesis in the ambient CO{sub 2} concentration than those in the elevated CO{sub 2} concentration for December 2006 and November 2007 (20 and 31 months after the treatments were applied), respectively, and A. acuminatissima grown with the low N treatment had 173%, 26%, and 121% greater net photosynthesis in trees grown in the ambient CO{sub 2} concentration than those in the elevated CO{sub 2} concentration for July 2006 (16 months after the treatments), December 2006 (20 months), and November 2007 (31 months), respectively, whereas

  12. Crystallinity-dependent substitutional nitrogen doping in ZnO and its improved visible light photocatalytic activity.

    Science.gov (United States)

    Yu, Zongbao; Yin, Li-Chang; Xie, Yingpeng; Liu, Gang; Ma, Xiuliang; Cheng, Hui-Ming

    2013-06-15

    Increasing visible light absorption of wide-bandgap photocatalysts (for example, ZnO and TiO2) plays a pivotal role in improving their photocatalytic activity. In this work, we show that substitutional nitrogen doping can be realized in semi-crystalline zinc oxide (ZnO) nanoparticles but fails for highly crystalline ZnO by heating the ZnO at a temperature of 400°C in gaseous ammonia atmosphere. The results suggest that substitutional nitrogen for lattice oxygen is strongly dependent on the crystallinity of ZnO. The nitrogen doped ZnO obtained shows an improved visible light photocatalytic activity in the degradation of organic dyes due to its increased visible light absorption. The origin of the increased visible light absorption is theoretically attributed to the formed N 2p localized states in the bandgap. PMID:23561822

  13. Submerged culture of Magne-tospirillum gryphiswaldense under N2-fixing condition and regulation of activity of nitrogen fixation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A submerged culture technique for Magnetospirillum gryphiswaldense under the nitrogen-fixing condition (microaerobic and N-limited) was set up. In N-limited medium with Na-lactate as a sole carbon source, the optical density (A600 nm) and activity of nitrogen fixation of cells were 1.3 and 217 nmol of ethylene produced per hour per A600nm respectively within 21 h by three times of feeds. The pH and temperature were controlled at 7.2 and 30℃ respectively, and the oxygen concentration was controlled by sparging with N2 containing 0.4%-0.8% of O2. The activity of nitrogen fixation of cells was obviously inhibited by oxygen and ammonium. It indicated that the posttranslational regulation of nitrogenase existed in M. gryphiswaldense.

  14. Influence of the atmospheric species water, oxygen, nitrogen and carbon dioxide on the degradation of aluminum doped zinc oxide layers

    NARCIS (Netherlands)

    Theelen, M.; Dasgupta, S.; Vroon, Z.; Kniknie, B.; Barreau, N.; Berkum, J. van; Zeman, M.

    2014-01-01

    Aluminum doped zinc oxide (ZnO:Al) layers were exposed to the atmospheric gases carbon dioxide (CO2), oxygen (O2), nitrogen (N 2) and air as well as liquid H2O purged with these gases, in order to investigate the chemical degradation behavior of these layers. The samples were analyzed by electrical,

  15. Paenibacillus brasilensis sp nov., a novel nitrogen-fixing species isolated from the maize rhizosphere in Brazil

    NARCIS (Netherlands)

    Weid, von der I.; Duarte, G.F.; Elsas, van J.D.; Seldin, L.

    2002-01-01

    Sixteen nitrogen-fixing strains isolated from the rhizosphere of maize planted in Cerrado soil, Brazil, which showed morphological and biochemical characteristics similar to the gas-forming Paenibacillus spp., were phenotypically and genetically characterized. Their identification as members of the

  16. UTILIZATION OF ORGANIC NITROGEN-SOURCES BY 2 PHYTOPLANKTON SPECIES AND A BACTERIAL ISOLATE IN PURE AND MIXED CULTURES

    NARCIS (Netherlands)

    IETSWAART, T; SCHNEIDER, PJ; PRINS, RA

    1994-01-01

    Algal production of dissolved organic carbon and the regeneration of nutrients from dissolved organic carbon by bacteria are important aspects of nutrient cycling in the sea, especially when inorganic nitrogen is limiting. Dissolved free amino acids are a major carbon source for bacteria and can be

  17. Adsorption/oxidation of sulfur-containing gases on nitrogen-doped activated carbon

    Directory of Open Access Journals (Sweden)

    Liu Qiang

    2016-01-01

    Full Text Available Coconut shell-based activated carbon (CAC was used for the removal of methyl mercaptan (MM. CAC was modified by urea impregnation and calcined at 450°C and 950°C. The desulfurization activity was determined in a fixed bed reactor under room temperature. The results showed that the methyl mercaptan adsorption/oxidation capacity of modified carbon caicined at 950°C is more than 3 times the capacity of original samples. On the other hand, the modified carbon caicined at 950°C also has a high capacity for the simultaneous adsorption/oxidation of methyl mercaptan and hydrogen sulfide.The introduce of basic nitrogen groups siginificantly increases the desulfurization since it can facilitate the electron transfer process between sulfur and oxygen. The structure and chemical properties are characterized using Boehm titration, N2 adsorption-desorption method, thermal analysis and elemental analysis. The results showed that the major oxidation products were dimethyl disulfide and methanesulfonic acid which adsorbed in the activated carbon.

  18. Oxygen- and nitrogen-co-doped activated carbon from waste particleboard for potential application in high-performance capacitance

    International Nuclear Information System (INIS)

    Graphical abstract: All electrodes showed excellent capacitance and retention versus discharge current density from 0.05 to 5 A/g. - Abstract: Oxygen- and nitrogen-co-doped activated carbons were obtained from phosphoric acid treated nitrogen-doped activated carbons which were prepared from waste particleboard bonded with urea-formaldehyde resin adhesives. The activated carbon samples obtained were tested as supercapacitors in two-electrode cell and extensive wetting 7 M KOH electrolytes. Their structural properties and surface chemistry, before the electrical testing, were investigated using elemental analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray diffraction, Raman spectra, and adsorption of nitrogen. Activated carbon treated by 4 M phosphoric acid of the highest capacitance (235 F/g) was measured in spite of a relatively lower surface (1360 m2/g) than that of the activated carbon treated by 2 M phosphoric acid (1433 m2/g). The surface chemistry, and especially oxygen- and nitrogen-containing functional groups, was found of paramount importance for the capacitive behavior and for the effective pore space utilization by the electrolyte ions

  19. Antifungal and antibacterial activity of endophytic penicillium species isolated from salvadora species

    International Nuclear Information System (INIS)

    Salvadora persica and S. S.oleoides are facultative holophytic plants, well known as miswak, are traditionally used to ensure oral hygiene among Muslim people in Asian and African counties. Species of Salvadora have a number of proven pharmacological importance. Besides, terrestrial fungi endophytic fungi are also gaining importance for the isolation of bioactive compounds. In this study 74 samples (root, shoot and leaves) from S. persica and S. oleoides were examined for endophytic fungi, 22 samples showed presence of Penicillium spp., 48 were found positive for aspergilli, whereas 10 samples showed infection of Fusarium solani, 4 were found infected with Macrophomina phaseolina and one with Rhizoctonia solani. Most of the Penicillium isolated were identified as P. restrictum, P. citrinum and P. canescens. In dual culture plate assay out of four Penicillium isolates tested, P. citrinum and one isolate of P. restrictum caused growth inhibition of all four test root rotting fungi, Fusarium solani, F. oxysporum, Macrophomina phaseolina and Rhizoctonia solani. Culture filtrates of Penicillium spp., were also evaluated against four common laboratory bacteria namely Bacillus subtilis, Staphylococcus aureus, Salmonella typhimurium and Escherichia coli and above mentioned root rotting fungi. Culture filtrates of endophytic Penicillium spp., also showed significant antibacterial and antifungal activity. Secondary metabolites of endophytic Penicillium spp., offer an exciting area of research for the discovery of novel antimicrobial compounds. (author)

  20. The Tomato Rhizosphere, an Environment Rich in Nitrogen-Fixing Burkholderia Species with Capabilities of Interest for Agriculture and Bioremediation▿

    OpenAIRE

    Caballero-Mellado, Jesús; Onofre-Lemus, Janette; Estrada-De Los Santos, Paulina; Martínez-Aguilar, Lourdes

    2007-01-01

    Burkholderia strains are promising candidates for biotechnological applications. Unfortunately, most of these strains belong to species of the Burkholderia cepacia complex (Bcc) involved in human infections, hampering potential applications. Novel diazotrophic Burkholderia species, phylogenetically distant from the Bcc species, have been discovered recently, but their environmental distribution and relevant features for agro-biotechnological applications are little known. In this work, the oc...

  1. Photocatalytic Activity and Characterization of Carbon-Modified Titania for Visible-Light-Active Photodegradation of Nitrogen Oxides

    Directory of Open Access Journals (Sweden)

    Chun-Hung Huang

    2012-01-01

    Full Text Available A variety of carbon-modified titania powders were prepared by impregnation method using a commercial available titania powder, Hombikat UV100, as matrix material while a range of alcohols from propanol to hexanol were used as precursors of carbon sources. Rising the carbon number of alcoholic precursor molecule, the modified titania showed increasing visible activities of NOx photodegradation. The catalyst modified with cyclohexanol exhibited the best activities of 62%, 62%, 59%, and 54% for the total NOx removal under UV, blue, green, and red light irradiation, respectively. The high activity with long wavelength irradiation suggested a good capability of photocatalysis in full visible light spectrum. Analysis of UV-visible spectrum indicated that carbon modification promoted visible light absorption and red shift in band gap. XPS spectroscopic analysis identified the existence of carbonate species (C=O, which increased with the increasing carbon number of precursor molecule. Photoluminescence spectra demonstrated that the carbonate species suppressed the recombination rate of electron-hole pair. As a result, a mechanism of visible-light-active photocatalyst was proposed according to the formation of carbonate species on carbon-modified TiO2.

  2. Nitrogen Incorporation in TiO2: Does It Make a Visible Light Photo-Active Material?

    Directory of Open Access Journals (Sweden)

    B. Viswanathan

    2012-01-01

    Full Text Available The possibility of hydrogen production by photo-catalytic decomposition of water on titania has provided the incentive for intense research. Titania is the preferred semiconductor for this process, in spite of its large band gap (~3.2 eV that restricts its utility only in the UV region. Various sensitization methodologies have been adopted to make titania to be active in the visible region. Doping of TiO2 with nitrogen is one such method. The purpose of this presentation is to examine the state and location of nitrogen introduced in TiO2 lattice and how far the shift of optical response to visible radiation can be beneficial for the observed photo-catalysis. The specific aspects that are discussed in this article are: (i N-doped titania surface adopts a non-native configuration, though the bulk material is still in the native configuration of pure TiO2 (ii\tThough the nitrogen doped materials showed optical response in the visible region, the changes/improvements in photo-catalytic activity are only marginal in most of the cases. (iii\tThe exact chemical nature/state of the introduced nitrogen, and its location in titania lattice, substitutional and/or interstitial, is still unclear (iv\tIs there a limit to the incorporation of nitrogen in the lattice of TiO2?

  3. Allometric analysis reveals relatively little variation in nitrogen versus biomass accrual in four plant species exposed to varying light, nutrients, water and CO2.

    Science.gov (United States)

    Bernacchi, Carl J; Thompson, Jennifer N; Coleman, James S; McConnaughay, Kelly D M

    2007-10-01

    Nitrogen concentrations in plant tissues can vary as a function of resource availability. Altered rates of plant growth and development under varying resource availabilities were examined to determine their effects on changes in whole-plant N use efficiency (NUE). Three species of old-field annuals were grown at broadly varying light, nutrient and water levels, and four species at varying atmospheric concentrations of CO2. Study results show highly variable N accrual rates when expressed as a function of plant age or size, but similar patterns of whole-plant N versus non-N biomass accrual over a wide range of environmental conditions. However, severely light-limited plants showed increased N versus biomass accrual for two of three species, and severely nutrient-limited plants had decreased N versus biomass accrual for all species. Whole-plant N accrual versus age and N versus biomass accrual increased under saturating water for two of three species. A marginally significant, modest decrease in N versus biomass accrual was found at high CO2 levels for two of four species. Physiological adjustments in NUE, expressed as N versus biomass accrual, were limited to environments with severely limited or overabundant resources. PMID:17727413

  4. THE EFFECT OF DIFFERENT DOSES OF NITROGEN (N) APPLICATION ON THE ANTIOXIDANT ACTIVITY AND PHENOLIC MATERIAL INGREDIENT OF SORREL (RUMEX ACETOSA L.)

    OpenAIRE

    Adiloğlu, Sevinç; Açıkgöz, Funda Eryılmaz; Dağlıoğlu, Figen; Barut Gök, Sıla; Altan, Deniz Damla

    2015-01-01

    In this study, The effect of different doses of nitrogen (N) application on the antioxidant activity and phenolic material ingredient of sorrel (Rumex acetosa L.) are investigated. In the test, four various doses of nitrogen NH4NO3 fertilizer have been applied to the plants. As a result, it has been determined that the antioxidant activity and phenolic compounds of Sorrel (Rumex acetosa L.) have parallels with the increase in the application of nitrogen.

  5. "Invented Invaders": An Engaging Activity to Teach Characteristics Control of Invasive Species

    Science.gov (United States)

    Lampert, Evan

    2015-01-01

    Invasive species, defined as exotic species that reach pest status, are major threats to global biodiversity. Although invasive species can belong to any taxonomic group, general characteristics such as rapid growth and reproduction are shared by many invasive species. "Invented Invaders" is a collaborative activity in which students…

  6. Anatomical basis of the change in leaf mass per area and nitrogen investment with relative irradiance within the canopy of eight temperate tree species

    Science.gov (United States)

    Aranda, I.; Pardo, F.; Gil, L.; Pardos, J. A.

    2004-05-01

    Changes in leaf mass per area (LMA), nitrogen content on a mass-basis (N m) and on an area basis (N a) with relative irradiance were assessed in leaves of eight temperate species harvested at different depths in a canopy. Relative irradiance (GSF) at the points of leaf sampling was estimated by hemispheric photographs. There was a strong species-dependent positive relationship between LMA and GSF for all species. Shade-tolerant species such as Fagus sylvatica showed lower LMA for the same GSF than less tolerant species as Quercus pyrenaica or Quercus petraea. The only evergreen species in the study, Ilex aquifollium, had the highest LMA, independent of light environment, with minimum values much higher than the rest of the broad-leaved species studied. There was no relation between N m and GSF for most species studied and only a very weak relation for the relative shade-intolerant species Q. pyrenaica. Within each species, the pattern of N a investment with regard to GSF was linked mainly to LMA. At the same relative irradiance, differences in N a among species were conditioned both by the LMA-GSF relationship and by the species N m value. The lowest N m value was measured in I. aquifollium (14.3 ± 0.6 mg g -1); intermediate values in Crataegus monogyna (16.9 ± 0.6 mg g -1) and Prunus avium (19.1 ± 0.6 mg g -1) and higher values, all in a narrow range (21.3 ± 0.6 to 23 ± 0.6 mg g -1), were measured for the other five species. Changes in LMA with the relative irradiance were linked both to lamina thickness (LT) and to palisade/spongy parenchyma ratio (PP/SP). In the second case, the LMA changes may be related to an increase in lamina density as palisade parenchyma involves higher cell packing than spongy parenchyma. However, since PP/SP ratio showed a weak species-specific relationship with LMA, the increase in LT should be the main cause of LMA variation.

  7. Mechanism of nitrogen metabolism-related parameters and enzyme activities in the pathophysiology of autism

    Directory of Open Access Journals (Sweden)

    Abu Shmais Ghada A

    2012-02-01

    Full Text Available Abstract Background There is evidence that impaired metabolism play an important role in the etiology of many neuropsychiatric disorders. Although this has not been investigated to date, several recent studies proposed that nitrogen metabolism-related parameters may have a pathophysiological role in autism. Methods The study enrolled 20 Saudi boys with autism aged 4 to 12 years and 20 healthy controls matched for age and gender. Levels of creatine, urea, ammonia, gamma-aminobutyric acid (GABA, glutamate:glutamine (Glu:Gln ratio, and enzymatic activities of glutamate dehydrogenase, 5'-nucleotidase, and adenosine deaminase (ADA were determined in plasma samples from both groups. Results We found a significant elevation of creatine, 5'-nucleotidase, GABA, and glutamic acid and a significant decrease in the enzymatic activity of ADA and glutamine level in patients with autism compared with healthy controls. The most significant variation between the two groups was found in the Glu:Gln ratio. Conclusion A raised Glu:Gln ratio together with positive correlations in creatine, GABA, and 5'-nucleotidase levels could contribute to the pathophysiology of autism, and might be useful diagnostic markers. The mechanism through which these parameters might be related to autism is discussed in detail.

  8. Together but different: co-occurring dune plant species differ in their water- and nitrogen-use strategies.

    Science.gov (United States)

    Bermúdez, Raimundo; Retuerto, Rubén

    2014-03-01

    Stress factors may severely constrain the range of plant physiological responses in harsh environments. Convergence of traits is expected in coastal dunes because of environmental filtering imposed by severe abiotic factors. However, the wide range of morphological and phenological traits exhibited by coexisting dune species suggests considerable variation in functional traits. We hypothesized that the constraints imposed by structural traits ought to translate into physiological differences. Five dominant species with different morphological traits, but coexisting in a homogeneous dune area in Northwest Spain, were selected for study. Soil characteristics and leaf functional traits were measured in April, June and November 2008. Integrated water-use efficiency (assessed by C isotope discrimination) and N acquisition and use strategies (estimated by N isotope composition) varied significantly among species and the differences changed over time. Species differences in specific leaf area, relative water content, leaf N and C:N ratio, also varied over time. The species differed in stomatal density but not in soil characteristics, with the exception of pH. Species differences in functional traits related to the use of resources suggest species niche segregation. Species-specific temporal effects on the use of these resources support temporal niche differentiation. Somewhat in contrast to the findings of previous studies on harsh environments, this study revealed a considerable level of functional diversity and complexity, suggesting that dune plant species have evolved species-specific strategies to survive by partitioning growth-limiting resources.

  9. Together but different: co-occurring dune plant species differ in their water- and nitrogen-use strategies.

    Science.gov (United States)

    Bermúdez, Raimundo; Retuerto, Rubén

    2014-03-01

    Stress factors may severely constrain the range of plant physiological responses in harsh environments. Convergence of traits is expected in coastal dunes because of environmental filtering imposed by severe abiotic factors. However, the wide range of morphological and phenological traits exhibited by coexisting dune species suggests considerable variation in functional traits. We hypothesized that the constraints imposed by structural traits ought to translate into physiological differences. Five dominant species with different morphological traits, but coexisting in a homogeneous dune area in Northwest Spain, were selected for study. Soil characteristics and leaf functional traits were measured in April, June and November 2008. Integrated water-use efficiency (assessed by C isotope discrimination) and N acquisition and use strategies (estimated by N isotope composition) varied significantly among species and the differences changed over time. Species differences in specific leaf area, relative water content, leaf N and C:N ratio, also varied over time. The species differed in stomatal density but not in soil characteristics, with the exception of pH. Species differences in functional traits related to the use of resources suggest species niche segregation. Species-specific temporal effects on the use of these resources support temporal niche differentiation. Somewhat in contrast to the findings of previous studies on harsh environments, this study revealed a considerable level of functional diversity and complexity, suggesting that dune plant species have evolved species-specific strategies to survive by partitioning growth-limiting resources. PMID:24213627

  10. The inhibition and adaptability of four wetland plant species to high concentration of ammonia wastewater and nitrogen removal efficiency in constructed wetlands.

    Science.gov (United States)

    Wang, Yuhui; Wang, Junfeng; Zhao, Xiaoxiang; Song, Xinshan; Gong, Juan

    2016-02-01

    Four plant species, Typha orientalis, Scirpus validus, Canna indica and Iris tectorum were selected to assess their physiological response and effects on nitrogen and COD removal to high total ammoniacal nitrogen (TAN) in constructed wetlands. Results showed that high TAN caused decreased relative growth rate, net photosynthetic rate, and leaf transpiration. C. indica and T. orientalis showed higher TAN adaptability than S. validus and I. tectorum. Below TAN of 200 mg L(-1), growth of C. indica and T. orientalis was less affected or even stimulated at TAN range 100-200 mg L(-1). However, S. validus and I. tectorum was obviously suppressed when TAN was above 100 mg L(-1). High TAN generated obvious oxidative stress showing increased proline and malondialdehyde contents, and superoxide dismutase was inhibited. It indicated that the threshold for plant self-bioremediation against high TAN was 200 mg L(-1). What's more, planted CWs showed higher nitrogen and COD removal. Removal rate of C. indica and T. orientalis was higher than S. validus and I. tectorum. PMID:26708488

  11. [Advances in studies on chemical constituents and biological activities of Desmodium species].

    Science.gov (United States)

    Liu, Chao; Wu, Ying; Zhang, Qian-Jun; Kang, Wen-Yi; Zhang, Long; Zhou, Qing-Di

    2013-12-01

    The chemical constituents isolated from Desmodium species (Leguminosae) included terpenoids, flavonoids, steroids, alkaloids compounds. Modem pharmacological studies have showed that the Desmodium species have antioxidant, antibacterial, anti-inflammatory, hepatoprotective, diuretic, antipyretic, analgesic and choleretic activity. This article mainly has reviewed the research advances of chemical constituents and biological activities of Desmodium species since 2003. PMID:24791478

  12. A minimal nitrogen fixation gene cluster from Paenibacillus sp. WLY78 enables expression of active nitrogenase in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Liying Wang

    Full Text Available Most biological nitrogen fixation is catalyzed by molybdenum-dependent nitrogenase, an enzyme complex comprising two component proteins that contains three different metalloclusters. Diazotrophs contain a common core of nitrogen fixation nif genes that encode the structural subunits of the enzyme and components required to synthesize the metalloclusters. However, the complement of nif genes required to enable diazotrophic growth varies significantly amongst nitrogen fixing bacteria and archaea. In this study, we identified a minimal nif gene cluster consisting of nine nif genes in the genome of Paenibacillus sp. WLY78, a gram-positive, facultative anaerobe isolated from the rhizosphere of bamboo. We demonstrate that the nif genes in this organism are organized as an operon comprising nifB, nifH, nifD, nifK, nifE, nifN, nifX, hesA and nifV and that the nif cluster is under the control of a σ(70 (σ(A-dependent promoter located upstream of nifB. To investigate genetic requirements for diazotrophy, we transferred the Paenibacillus nif cluster to Escherichia coli. The minimal nif gene cluster enables synthesis of catalytically active nitrogenase in this host, when expressed either from the native nifB promoter or from the T7 promoter. Deletion analysis indicates that in addition to the core nif genes, hesA plays an important role in nitrogen fixation and is responsive to the availability of molybdenum. Whereas nif transcription in Paenibacillus is regulated in response to nitrogen availability and by the external oxygen concentration, transcription from the nifB promoter is constitutive in E. coli, indicating that negative regulation of nif transcription is bypassed in the heterologous host. This study demonstrates the potential for engineering nitrogen fixation in a non-nitrogen fixing organism with a minimum set of nine nif genes.

  13. The Relationship of Nitrogen and C/N Ratio with Secondary Metabolites Levels and Antioxidant Activities in Three Varieties of Malaysian Kacip Fatimah (Labisia pumila Blume

    Directory of Open Access Journals (Sweden)

    Mohd Hafiz Ibrahim

    2011-06-01

    Full Text Available Kacip Fatimah (Labisia pumila Blume, one of the most famous and widely used herbs, especially in Southeast Asia, is found to have interesting bioactive compounds and displays health promoting properties. In this study, the antioxidant activities of the methanol extracts of leaves, stems and roots of three varieties of L. pumila (var. alata, pumila and lanceolata were evaluated in an effort to compare and validate the medicinal potential of this indigenous Malaysian herb species. The antioxidant activity determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH assay, as well as the total amount of phenolics and flavonoids were the highest in the leaves, followed by the stems and roots in all the varieties. A similar trend was displayed by the ferric reducing antioxidant potential (FRAP activity, suggesting that the L. pumila varieties possess high foliar antioxidant properties. At low FRAP activity concentrations, the values of the leaves’ inhibition activity in the three varieties were significantly higher than those of the stems and roots, with var. alata exhibiting higher antioxidant activities and total contents of phenolics and flavonoids compared to the varieties pumila and lanceolata. The high production of secondary metabolites and antioxidant activities in var. alata were firmly related to low nitrogen content and high C/N ratio in plant parts. The study also demonstrated a positive correlation between secondary metabolite content and antioxidant activities, and revealed that the consumption of L. pumila could exert several beneficial effects by virtue of its antioxidant activity.

  14. The relationship of nitrogen and C/N ratio with secondary metabolites levels and antioxidant activities in three varieties of Malaysian kacip Fatimah (Labisia pumila Blume).

    Science.gov (United States)

    Ibrahim, Mohd Hafiz; Jaafar, Hawa Z E

    2011-01-01

    Kacip Fatimah (Labisia pumila Blume), one of the most famous and widely used herbs, especially in Southeast Asia, is found to have interesting bioactive compounds and displays health promoting properties. In this study, the antioxidant activities of the methanol extracts of leaves, stems and roots of three varieties of L. pumila (var. alata, pumila and lanceolata) were evaluated in an effort to compare and validate the medicinal potential of this indigenous Malaysian herb species. The antioxidant activity determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, as well as the total amount of phenolics and flavonoids were the highest in the leaves, followed by the stems and roots in all the varieties. A similar trend was displayed by the ferric reducing antioxidant potential (FRAP) activity, suggesting that the L. pumila varieties possess high foliar antioxidant properties. At low FRAP activity concentrations, the values of the leaves' inhibition activity in the three varieties were significantly higher than those of the stems and roots, with var. alata exhibiting higher antioxidant activities and total contents of phenolics and flavonoids compared to the varieties pumila and lanceolata. The high production of secondary metabolites and antioxidant activities in var. alata were firmly related to low nitrogen content and high C/N ratio in plant parts. The study also demonstrated a positive correlation between secondary metabolite content and antioxidant activities, and revealed that the consumption of L. pumila could exert several beneficial effects by virtue of its antioxidant activity. PMID:21716173

  15. A Study on Relationship between Nitrogen Accumulation of Severa Wetland Plant Species and Biomass of Their Rhizospheric Nitrogen-fixing Bacteria%几种湿地植物的氮素累积量与其根际固氮菌总数之间相关性分析

    Institute of Scientific and Technical Information of China (English)

    李琦; 陈建中; 戴丽; 郑潭

    2011-01-01

    In order to investigate the correlation of nitrogen and phosphorus accumulation with rhizospheric microbes, as well as the assimilative potentials of several wetland plant species, such relationships of Phragmites communis, Zizania caduciflora Hand Mazz, Cyperus papyrus Linn, Scirpus validus Vahl, Canna indica and Iris germanica Linn were studied in combination with the research on wetland restoration and its demonstration technologies for Miju River estuary situated at the northern Erhai Lake. The correlation between nitrogen accumulation of Phragmites communis and Canna indica and biomass of their rhizospheric nitrogen-fixing bacteria was found evidently positive, whilst that of the others was unmarked. Furthermore, simple regression and partial correlation analyses were also conducted to focus on the influence of environmental factors of the wetland system such as total nitrogen in surface soil, total nitrogen and dissolved oxygen in water body. In general, all of the factors would make rather great impacts on the biomass of rhizospheric nitrogen-fixing bacteria. However, the correlation of nitrogen accumulation of Phragmites communis and Canna with their rhizospheric nitrogen-fixing bacteria was slightly affected by those environmental factors, and it was further confirmed that there were co-metabolic activities between their nitrogen accumulation and rhizospheric nitrogen-fixing bacteria.%为研究湿地植物的氮、磷累积量与其根际微生物之间的相关性,并调查湿地植物的净化潜能,结合位于洱海北部的弥苴河河口湿地恢复和示范技术,对芦苇、茭草、纸莎草.水葱、美人蕉和鸢尾6种湿地植物进行了相关性研究分析。结果表明,芦苇,美人蕉氮素累积量与其根际固氮菌总数呈显著正相关关系,而其他4种湿地植物的相关性不显著。针对湿地系统的环境因素,如表层土壤全氮、湿地水体总氮和溶解氧的影响,也作了简单的回归

  16. Antibacterial Activity of Extracts of Three Croton Species Collected in Mpumalanga Region in South Africa

    OpenAIRE

    Selowa, SC; Shai, LJ; Masoko, P; Mokgotho, MP; Magano, SR

    2009-01-01

    The antibacterial activities of three Croton species were compared using bioautography and the serial microdilution methods. The methanolic extracts of all the species had low activity against Escherichia coli. The highest activity was observed with Croton megalobotrys against Enterococcus faecalis with a minimal inhibitory concentration (MIC) value of 0.02 mg/ml. Croton steenkapianus extracts were the least active of the species investigated, only managing an MIC value of 0.625 mg/ml against...

  17. Regulation of nitrogen fixation in Klebsiella pneumoniae and Azotobacter vinelandii: NifL, transducing two environmental signals to the nif transcriptional activator NifA.

    Science.gov (United States)

    Schmitz, Ruth A; Klopprogge, Kai; Grabbe, Roman

    2002-05-01

    by the GlnK protein, a paralogue PII-protein, which appears to interact with the NifL/NifA regulatory system via direct protein-protein interaction. It is not currently known whether GlnK interacts with NifL alone or affects the NifL/NifA-complex; moreover the effects appear to be the opposite in K. pneumoniae and A. vinelandii. In addition to these environmental signals, adenine nucleotides also affect the inhibitory function of NifL; in the presence of ATP or ADP the inhibitory effect on NifA activity in vitro is increased. The NifL proteins from the two organisms differ, however, in that stimulation of K. pneumoniae-NifL occurs only when synthesized under nitrogen excess, and is correlated with the ability to hydrolyze ATP. In general, transduction of environmental signals to the nif regulatory system appears to involve a conformational change of NifL or the NifL/NifA complex. However, experimental data suggest that K. pneumoniae and A. vinelandii employ significantly different species-specific mechanisms of signal transduction. PMID:11931553

  18. Regulation of Azorhizobium caulinodans ORS571 nitrogen fixation (nif/fix) genes.

    OpenAIRE

    Stigter, J.

    1994-01-01

    Biological nitrogen fixation is the microbial process by which atmospheric dinitrogen (N 2 ) is reduced to ammonia. In all microbes studied, dinitrogen reduction is catalyzed by a highly conserved enzyme complex, called nitrogenase. The nitrogenase subunits and functions required for nitrogenase assembly and activity are encoded by the nitrogen fixation (nif/fix) genes.Nitrogen-fixing organisms can be roughly divided into two major groups: the free-living nitrogen fixing (diazotrophic) specie...

  19. Inhibition of nitrogen-fixing activity of the cyanobiont affects the localization of glutamine synthetase in hair cells of Azolla.

    Science.gov (United States)

    Uheda, Eiji; Maejima, Kazuhiro

    2009-10-15

    In the Azolla-Anabaena association, the host plant Azolla efficiently incorporates and assimilates ammonium ions that are released from the nitrogen-fixing cyanobiont, probably via glutamine synthetase (GS; EC 6.3.1.2) in hair cells, which are specialized cells protruding into the leaf cavity. In order to clarify the regulatory mechanism underlying ammonium assimilation in the Azolla-Anabaena association, Azolla plants were grown under an argon environment (Ar), in which the nitrogen-fixing activity of the cyanobiont was inhibited specifically and completely. The localization of GS in hair cells was determined by immunoelectron microscopy and quantitative analysis of immunogold labeling. Azolla plants grew healthily under Ar when nitrogen sources, such as NO(3)(-) and NH(4)(+), were provided in the growth medium. Both the number of cyanobacterial cells per leaf and the heterocyst frequency of the plants under Ar were similar to those of plants in a nitrogen environment (N(2)). In hair cells of plants grown under Ar, regardless of the type of nitrogen source provided, only weak labeling of GS was observed in the cytoplasm and in chloroplasts. In contrast, in hair cells of plants grown under N(2), abundant labeling of GS was observed in both sites. These findings indicate that specific inhibition of the nitrogen-fixing activity of the cyanobiont affects the localization of GS isoenzymes. Ammonium fixed and released by the cyanobiont could stimulate GS synthesis in hair cells. Simultaneously, the abundant GS, probably GS1, in these cells, could assimilate ammonium rapidly. PMID:19464754

  20. Responses of Nitrogen and related enzyme Activities to Fertilization in Rhizosphere of Wheat

    Institute of Scientific and Technical Information of China (English)

    YUANLING; YUSHANGQI; 等

    1997-01-01

    In the present experiment,wheat seedlings(Trticucum aestivum L.)were grown on a purple soil with various fertilizer treatments in order to investigate the responses of nitrogen and related enzyme activities in the rhizosphere,The results revealed the increments of both organic matter and total N in the soil with the proximity to the growing roots,especially in treatment of supplying pig manure in combination with chemical fertilizer,suggesting that they could ome from root and microorganism exudation which could be intensified by inorganic-organic fertiliztion,being of benefit to improving the physical and bilogical envi-ronment in the rhizosphere of wheat.Much more inorganic N was observed in the fertilized soils surrounding wheat roots than in the CK treatment ,indicating ,the improvement of crop N supply in the rhizosphere of wheat by fertilization. The activities of invertase,urease and protease in the root zone were greatly enhanced as compared to those in the other parts of soil except that the urease activities were similar in the rhizospher and nonrhi-zosphere of the CK and pig manure treatments,indicating that invertase and protese could be produced by growing roots and rhizosphere microorganisms,in contrast to urease which could be stimulated by urea,Also,significant increment of chemical fertilizer combined with pig manure,suggested that fertilization not only accelerated the renewal of organic matter bu also enhanced bioavailability of organic N in that soil zone .This could be the reason why the total amount of inorganic N available for plants was increased more obviously in the rhizosphere of wheat of the fertilizaton treatments than in taht of the CK treatment.

  1. Water activity and activation diameters from hygroscopicity data - Part II: Application to organic species

    Directory of Open Access Journals (Sweden)

    K. A. Koehler

    2006-01-01

    Full Text Available A method has been developed for using particle hygroscopicity measurements made with a humidified tandem differential mobility analyzer (HTDMA to determine water activity as a function of solute weight percent. In Part I, the method was tested for particles composed of sodium chloride and ammonium sulfate. Here, we report results for several atmospherically-relevant organic species: glutaric acid, malonic acid, oxalic acid and levoglucosan. Predicted water activities for aqueous dicarboxylic acid solutions are quite similar in some cases to published estimates and the simplified predictions of Köhler theory, while in other cases substantial differences are found, which we attribute primarily to the semivolatile nature of these compounds that makes them difficult to study with the HTDMA. In contrast, estimates of water activity for levoglucosan solutions compare very well with recently-reported measurements and with published data for aqueous glucose and fructose solutions. For all studied species, the critical dry diameters active at supersaturations between 0.2 and 1% that are computed with the HTDMA-derived water activities are generally within the experimental error (~20% estimated in previously-published direct measurements using cloud condensation nuclei counters. For individual compounds, the variations in reported solution water activity lead to uncertainties in critical dry diameters of 5-25%, not significantly larger than the uncertainty in the direct measurements. To explore the impact of these uncertainties on modeled aerosol-cloud interactions, we incorporate the variations in estimates of solution water activities into the description of hygroscopic growth of aerosol particles in an adiabatic parcel model and examine the impact on the predicted drop number concentrations. For the limited set of initial conditions examined here, we find that the uncertainties in critical dry diameters for individual species lead to 0-21% changes in

  2. A marine eutrophication impacts assessment method in LCIA coupling coastal ecosystems exposure to nitrogen and species sensitivity to hypoxia

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias; Koski, Marja; Hauschild, Michael Zwicky

    on probabilistic Species Sensitivity Distribution (SSD) methodologies to quantify potential species losses from hypoxia. Results show 2 orders of magnitude global spatial differentiation on a Large Marine Ecosystems (LME) spatial resolution. Adding an N-fate model completes CFs for anthropogenic N-forms, thus...

  3. Mechanisms of nitrogen re-distribution in response to enzyme activities and the effects on nitrogen use efficiency in brassica napus during later growth stages

    International Nuclear Information System (INIS)

    In order to investigate the mechanisms of nitrogen (N) re-distribution in response to proteolytic enzyme (PE), glutamine synthetase (GS) and glutamate synthetase (GOGAT) activities and the effects on N use efficiency (NUE). Two oilseed rape genotypes were grown in sand culture in a greenhouse under normal (15.0 mmol L-1 NO/sub 3/) and limited-N (7.5 mmol L-1 NO/sub 3/) levels. Isotope (15N) labeling and enzyme inhibitors against the PE, GS and GOGAT enzymes were used. We found that, when the two genotypes were subjected to specific inhibitors of PE, GS, and GOGAT, the activities of these enzymes were significantly decreased, resulting in reduced N re-distributed from leaf to grain, as well as reduced NUE. L-glutamine and free amino acid contents in the phloem sap were primarily influenced by PE and GS activities, whereas grain yield was primary regulated by GOGAT activity during the later growth stages. These findings suggest that PE, GS, and GOGAT are key enzymes for the regulation of N re-distribution in plant tissues during later growth stages, with grain yield and NUE of oilseed rape being positively regulated by PE, GS and GOGAT activities. (author)

  4. Southern leaf blight disease severity is correlated with decreased maize leaf epiphytic bacterial species richness and the phyllosphere bacterial diversity decline is enhanced by nitrogen fertilization

    Directory of Open Access Journals (Sweden)

    Heather eManching

    2014-08-01

    Full Text Available Plant leaves are inhabited by a diverse group of microorganisms that are important contributors to optimal growth. Biotic and abiotic effects on plant growth are usually studied in controlled settings examining response to variation in single factors and in field settings with large numbers of variables. Multi-factor experiments with combinations of stresses bridge this gap, increasing our understanding of the genotype-environment-phenotype functional map for the host plant and the affiliated epiphytic community. The maize inbred B73 was exposed to single and combination abiotic and the biotic stress treatments: low nitrogen fertilizer and high levels of infection with southern leaf blight (causal agent Cochliobolus heterostrophus. Microbial epiphyte samples were collected at the vegetative early-season phase and species composition was determined using 16S ribosomal intergenic spacer analysis. Plant traits and level of southern leaf blight disease were measured late-season. Bacterial diversity was different among stress treatment groups (P< 0.001. Lower species richness—alpha diversity--was correlated with increased severity of southern leaf blight disease when disease pressure was high. Nitrogen fertilization intensified the decline in bacterial alpha diversity. While no single bacterial ribotype was consistently associated with disease severity, small sets of ribotypes were good predictors of disease levels. Difference in leaf bacterial-epiphyte diversity early in the season were correlated with plant disease severity, supporting further tests of microbial epiphyte-disease correlations for use in predicting disease progression.

  5. A novel endo-hydrogenase activity recycles hydrogen produced by nitrogen fixation.

    Directory of Open Access Journals (Sweden)

    Gordon Ng

    Full Text Available BACKGROUND: Nitrogen (N(2 fixation also yields hydrogen (H(2 at 1:1 stoichiometric amounts. In aerobic diazotrophic (able to grow on N(2 as sole N-source bacteria, orthodox respiratory hupSL-encoded hydrogenase activity, associated with the cell membrane but facing the periplasm (exo-hydrogenase, has nevertheless been presumed responsible for recycling such endogenous hydrogen. METHODS AND FINDINGS: As shown here, for Azorhizobium caulinodans diazotrophic cultures open to the atmosphere, exo-hydrogenase activity is of no consequence to hydrogen recycling. In a bioinformatic analysis, a novel seven-gene A. caulinodans hyq cluster encoding an integral-membrane, group-4, Ni,Fe-hydrogenase with homology to respiratory complex I (NADH: quinone dehydrogenase was identified. By analogy, Hyq hydrogenase is also integral to the cell membrane, but its active site faces the cytoplasm (endo-hydrogenase. An A. caulinodans in-frame hyq operon deletion mutant, constructed by "crossover PCR", showed markedly decreased growth rates in diazotrophic cultures; normal growth was restored with added ammonium--as expected of an H(2-recycling mutant phenotype. Using A. caulinodans hyq merodiploid strains expressing beta-glucuronidase as promoter-reporter, the hyq operon proved strongly and specifically induced in diazotrophic culture; as well, hyq operon induction required the NIFA transcriptional activator. Therefore, the hyq operon is constituent of the nif regulon. CONCLUSIONS: Representative of aerobic N(2-fixing and H(2-recycling alpha-proteobacteria, A. caulinodans possesses two respiratory Ni,Fe-hydrogenases: HupSL exo-hydrogenase activity drives exogenous H(2 respiration, and Hyq endo-hydrogenase activity recycles endogenous H(2, specifically that produced by N(2 fixation. To benefit human civilization, H(2 has generated considerable interest as potential renewable energy source as its makings are ubiquitous and its combustion yields no greenhouse gases. As

  6. Direct Functionalization of Nitrogen Heterocycles via Rh-Catalyzed C-H Bond Activation

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Jared; Bergman, Robert; Ellman, Jonathan

    2008-02-04

    Nitrogen heterocycles are present in many compounds of enormous practical importance, ranging from pharmaceutical agents and biological probes to electroactive materials. Direct funtionalization of nitrogen heterocycles through C-H bond activation constitutes a powerful means of regioselectively introducing a variety of substituents with diverse functional groups onto the heterocycle scaffold. Working together, our two groups have developed a family of Rh-catalyzed heterocycle alkylation and arylation reactions that are notable for their high level of functional-group compatibility. This Account describes their work in this area, emphasizing the relevant mechanistic insights that enabled synthetic advances and distinguished the resulting transformations from other methods. They initially discovered an intramolecular Rh-catalyzed C-2-alkylation of azoles by alkenyl groups. That reaction provided access to a number of di-, tri-, and tetracyclic azole derivatives. They then developed conditions that exploited microwave heating to expedite these reactions. While investigating the mechanism of this transformation, they discovered that a novel substrate-derived Rh-N-heterocyclic carbene (NHC) complex was involved as an intermediate. They then synthesized analogous Rh-NHC complexes directly by treating precursors to the intermediate [RhCl(PCy{sub 3}){sub 2}] with N-methylbenzimidazole, 3-methyl-3,4-dihydroquinazolein, and 1-methyl-1,4-benzodiazepine-2-one. Extensive kinetic analysis and DFT calculations supported a mechanism for carbene formation in which the catalytically active RhCl(PCy{sub 3}){sub 2} fragment coordinates to the heterocycle before intramolecular activation of the C-H bond occurs. The resulting Rh-H intermediate ultimately tautomerizes to the observed carbene complex. With this mechanistic information and the discovery that acid co-catalysts accelerate the alkylation, they developed conditions that efficiently and intermolecularly alkylate a variety of

  7. Experimental study on activated carbon-nitrogen pair in a prototype pressure swing adsorption refrigeration system

    Science.gov (United States)

    Anupam, Kumar; Palodkar, Avinash V.; Halder, G. N.

    2016-04-01

    Pressure swing adsorption of nitrogen onto granular activated carbon in the single-bed adsorber-desorber chamber has been studied at six different pressures 6-18 kgf/cm2 to evaluate their performance as an alternative refrigeration technique. Refrigerating effect showed a linear rise with an increase in the operating pressure. However, the heat of adsorption and COP exhibited initial rise with the increasing operating pressure but decreased later after reaching a maximum value. The COP initially increases with operating pressures however, with the further rise of operating pressure it steadily decreased. The highest average refrigeration, maximum heat of adsorption and optimum coefficient of performance was evaluated to be 415.38 W at 18 kgf/cm2, 92756.35 J at 15 kgf/cm2 and 1.32 at 12 kgf/cm2, respectively. The system successfully produced chilled water at 1.7 °C from ambient water at 28.2 °C.

  8. Measurement of nitrogen in vivo by neutron activation analysis: further developments and applications

    International Nuclear Information System (INIS)

    Some recent work has shown that nitrogen in clothing or skin is detected with one third the efficiency of that in the bulk of the body. The use of graphite neutron reflectors would remove this sharp change at the body surface. Whole body composition studies have shown that nitrogen can be predicted well from whole body potassium, weight, fat and body size measurements. Whole body nitrogen has been used with other measurements (triceps fat fold, arm muscle diameter, weight) to analyse some of the components of weight change pre- and post-operatively in people suffering from Crohn's disease. (author)

  9. Seasonal budgets of reactive nitrogen species and ozone over the United States, and export fluxes to the global atmosphere

    OpenAIRE

    Liang, Jinyou; Horowitz, Larry W.; Jacob, Daniel James; Wang, Yuhang; Fiore, Arlene M.; Logan, Jennifer A.; Gardner, Geraldine M.; Munger, J. William

    1998-01-01

    A three-dimensional, continental-scale photochemical model is used to investigate seasonal budgets of O3 and NOy species (including NOx and its oxidation products) in the boundary layer over the United States and to estimate the export of these species from the U.S. boundary layer to the global atmosphere. Model results are evaluated with year-round observations for O3, CO, and NOy species at nonurban sites. A seasonal transition from NOx to hydrocarbon-limited conditions for O3 production ov...

  10. CARBONACEOUS, NITROGENOUS AND PHOSPHORUS MATTERS REMOVAL FROM DOMESTIC WASTEWATER BY AN ACTIVATED SLUDGE REACTOR OF NITRIFICATION-DENITRIFICATION TYPE

    Directory of Open Access Journals (Sweden)

    MOHAMAD ALI FULAZZAKY

    2009-03-01

    Full Text Available This paper proposes an environmental engineering method based on biotechnology approach as one of the expected solutions that should be considered to implementing the activated sludge for improving the quality of water and living environment, especially to remove the major pollutant elements of domestic wastewater. Elimination of 3 major pollutant elements, i.e., carbon, nitrogen and phosphor containing the domestic wastewater is proposed to carry out biological method of an anoxic-aerobic reactor therein these types of pollutants should be consecutively processed in three steps. Firstly, eliminate the carbonaceous matter in the aerobic reactor. Secondly, to remove the carbonaceous and nitrogenous matters, it is necessary to modify the reactor’s nature from the aerobic condition to an anoxic-aerobic reactor. And finally, when the cycle of nitrification-denitrification is stable to achieve the target’s efficiency of reactor by adding the ferric iron into the activated sludge, it can be continued to remove the carbonaceous, nitrogenous and phosphorous matters simultaneously. The efficiency of carbonaceous and nitrogenous matters removal was confirmed with the effluent standard, COD is less than 100 mgO2/L and the value of global nitrogen is less than 10 mgN/L. The effectiveness of suspended matter removal is higher than 90% and the decantation of activated sludge is very good as identifying the Molhman’s index is below of 120 mL/L. The total phosphorus matter removal is more effective than the soluble phosphorus matter. By maintaining the reactor’s nature at the suitable condition, identifying the range of pH between 6.92 and 7.16 therefore the excellent abatement of phosphor of about 80% is achieving with the molar Fe/P ratio of 1.4.

  11. Nitrogen, Phosphor, and Potassium Level in Soil and Oil Palm Tree at various Composition of plant species mixtures grown

    Science.gov (United States)

    Hanum, C.; Rauf, A.; Fazrin, D. A.; Habibi, A. R.

    2016-08-01

    In productive oil palm plantation areas, poor vegetation is generally caused by low light intensity. This condition causes excessive erosion and decreases soil fertility. One of the efforts for soil and water conservation at oil palm plantations is through increased vegetation diversity. The changes of soil and plant nitrogen, phosporus, and potassium content, observed by planting two types of herbs under oil palm tree, with different compositions. Vegetation composition was set as: Arachis glabrata 100%; Stenotaprum secundatum 100%; Arachis glabrata 50% + Stenotaprum secundatum 50%; Arachis glabrata 75% + Stenotaprum secundatum 25%; Arachis glabrata 25% + Stenotaprum secundatum 75%. The shoot and root fresh/dry weight, nutrient content (nitrogen, phosphor, and potassium) of each cutting were measured at the end of the experiment. Ten of treatment plant were harvested and divided shoots and roots after washing out of soil. Biomass samples were dried at 70 °C for 48 h and weighed. The total N and its proportional concentration (N%) were analyzed with the micro- Kjeldahl method. Potasium analyzing with flamephotometry, and phosphor and from samples was determined by analyzing with spectrophotometry method. The results showed the highest shoot growth of A.glabarata if planting was mixed with S. secundatum, but the result was different with S.secundatum being superior if planted with monoculture system. Combination of interrow cultivation is more recommended for soil conservation and nutrient maintenance in palm oil trees were A. Glabarata 75% + S.secundatum 25%.

  12. Effects of increased deposition of atmospheric nitrogen on an upland moor: leaching of N species and soil solution chemistry

    International Nuclear Information System (INIS)

    This study was designed to investigate the leaching response of an upland moorland to long-term (10 yr) ammonium nitrate additions of 40, 80 and 120 kg N ha-1 yr-1 and to relate this response to other indications of potential system damage, such as acidification and cation displacement. Results showed increases in nitrate leaching only in response to high rates of N input, in excess of 96 and 136 kg total N input ha-1 yr-1 for the organic Oh horizon and mineral Eag horizon, respectively. Individual N additions did not alter ammonium leaching from either horizon and ammonium was completely retained by the mineral horizon. Leaching of dissolved organic nitrogen (DON) from the Oh horizon was increased by the addition of 40 kg N ha-1 yr-1, but in spite of increases, retention of total dissolved nitrogen reached a maximum of 92% and 95% of 80 kg added N ha-1 yr-1 in the Oh and Eag horizons, respectively. Calcium concentrations and calcium/aluminium ratios were decreased in the Eag horizon solution with significant acidification mainly in the Oh horizon leachate. Nitrate leaching is currently regarded as an early indication of N saturation in forest systems. Litter C:N ratios were significantly lowered but values remained above a threshold predicted to increase leaching of N in forests. - Nitrate leaching from an upland moor podsol was significantly increased only in response to rates of N deposition in excess of 96 kg N ha-1 yr-1

  13. Effects of increased deposition of atmospheric nitrogen on an upland moor: leaching of N species and soil solution chemistry.

    Science.gov (United States)

    Pilkington, M G; Caporn, S J M; Carroll, J A; Cresswell, N; Lee, J A; Ashenden, T W; Brittain, S A; Reynolds, B; Emmett, B A

    2005-05-01

    This study was designed to investigate the leaching response of an upland moorland to long-term (10 yr) ammonium nitrate additions of 40, 80 and 120 kg N ha(-1) yr(-1) and to relate this response to other indications of potential system damage, such as acidification and cation displacement. Results showed increases in nitrate leaching only in response to high rates of N input, in excess of 96 and 136 kg total N input ha(-1) yr(-1) for the organic Oh horizon and mineral Eag horizon, respectively. Individual N additions did not alter ammonium leaching from either horizon and ammonium was completely retained by the mineral horizon. Leaching of dissolved organic nitrogen (DON) from the Oh horizon was increased by the addition of 40 kg N ha(-1) yr(-1), but in spite of increases, retention of total dissolved nitrogen reached a maximum of 92% and 95% of 80 kg added N ha(-1) yr(-1) in the Oh and Eag horizons, respectively. Calcium concentrations and calcium/aluminium ratios were decreased in the Eag horizon solution with significant acidification mainly in the Oh horizon leachate. Nitrate leaching is currently regarded as an early indication of N saturation in forest systems. Litter C:N ratios were significantly lowered but values remained above a threshold predicted to increase leaching of N in forests.

  14. Effects of high atmospheric CO{sub 2} concentration on root hydraulic conductivity of conifers depend on species identity and inorganic nitrogen source

    Energy Technology Data Exchange (ETDEWEB)

    Gebauer, Tobias [University of Illinois at Chicago, Department of Biological Sciences, 840 West Taylor Street, Chicago, IL 60607 (United States); BassiriRad, Hormoz, E-mail: hormoz@uic.edu [University of Illinois at Chicago, Department of Biological Sciences, 840 West Taylor Street, Chicago, IL 60607 (United States)

    2011-12-15

    We examined root hydraulic conductivity (L{sub p}) responses of one-year-old seedlings of four conifers to the combined effects of elevated CO{sub 2} and inorganic nitrogen (N) sources. We found marked interspecific differences in L{sub p} responses to high CO{sub 2} ranging from a 37% increase in P. abies to a 27% decrease in P. menziesii, but these effects depended on N source. The results indicate that CO{sub 2} effects on root water transport may be coupled to leaf area responses under nitrate (NO{sub 3}{sup -}), but not ammonium (NH{sub 4}{sup +}) dominated soils. To our knowledge, this is the first study that highlights the role of inorganic N source and species identity as critical factors that determine plant hydraulic responses to rising atmospheric CO{sub 2} levels. The results have important implications for understanding root biology in a changing climate and for models designed to predict feedbacks between rising atmospheric CO{sub 2}, N deposition, and ecohydrology. - Highlights: > Root hydraulic conductivity (L{sub p}) in conifers is affected by increased atmospheric CO{sub 2} levels. > This response depends on inorganic N source and species identity. > This is the first report of L{sub p} responses to elevated CO{sub 2} and N source in multiple species. - Root water transport responses to rising atmospheric CO{sub 2} concentration depends on species identity and inorganic N sources.

  15. Impacts of nitrogen deposition on herbaceous ground flora and epiphytic foliose lichen species in southern Ontario hardwood forests.

    Science.gov (United States)

    McDonough, Andrew M; Watmough, Shaun A

    2015-01-01

    In this study 70 sugar maple (Acer saccharum Marsh.) dominated plots in Ontario, Canada were sampled in the spring of 2009 and 2010 and herbaceous plant and epiphytic foliose lichen species data were compared against modeled N and S deposition data, climate parameters and measured soil and plant/lichen S and N concentration. Herbaceous plant species richness was positively correlated with temperature and indices of diversity (Shannon Weiner and Simpson's Index) were positively correlated with soil pH but not N or S deposition or standardized foliar N scores. Herbaceous community composition was strongly controlled by traditional factors, but there was a small and significant influence of atmospheric S and N deposition. Epiphytic lichen species richness exhibited a strong negative relationship with standardized foliar N score and only one lichen species (Phaeophyscia rubropulchra) was observed at sites with a standardized foliar N score of 0.76. PMID:25305468

  16. Antioxidant, hemolytic and cytotoxic activities of Senecio species used in traditional medicine of northwestern Argentina.

    Science.gov (United States)

    Lizarraga, Emilio; Castro, Felipe; Fernández, Francisco; de Lampasona, Marina P; Catalán, César A N

    2012-05-01

    Senecio nutans Sch. Bip., S. viridis var. viridis Phill. and S. spegazzinii Cabrera are native species used in traditional medicine of northwestern Argentina. The total phenolics, flavonoids and caffeoylquinic acids contents, as well as radical scavenging, antioxidant, hemolytic and cytotoxic activities of aqueous extracts (infusion and decoction) of all three species were determined. S. nutans was the most active. The extracts did not show antibacterial activity. Alkaloids were not detected in any of the aqueous extracts of the three studied species. PMID:22799087

  17. Role of reactive nitrogen species generated via inducible nitric oxide synthase in vesicant-induced lung injury, inflammation and altered lung functioning

    Energy Technology Data Exchange (ETDEWEB)

    Sunil, Vasanthi R., E-mail: sunilvr@eohsi.rutgers.edu [Department of Pharmacology and Toxicology, Rutgers University, Ernest Mario School of Pharmacy Piscataway, NJ (United States); Shen, Jianliang; Patel-Vayas, Kinal; Gow, Andrew J. [Department of Pharmacology and Toxicology, Rutgers University, Ernest Mario School of Pharmacy Piscataway, NJ (United States); Laskin, Jeffrey D. [Department of Environmental and Occupational Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ (United States); Laskin, Debra L. [Department of Pharmacology and Toxicology, Rutgers University, Ernest Mario School of Pharmacy Piscataway, NJ (United States)

    2012-05-15

    Pulmonary toxicity induced by sulfur mustard and related vesicants is associated with oxidative stress. In the present studies we analyzed the role of reactive nitrogen species (RNS) generated via inducible nitric oxide synthase (iNOS) in lung injury and inflammation induced by vesicants using 2-chloroethyl ethyl sulfide (CEES) as a model. C57Bl/6 (WT) and iNOS −/− mice were sacrificed 3 days or 14 days following intratracheal administration of CEES (6 mg/kg) or control. CEES intoxication resulted in transient (3 days) increases in bronchoalveolar lavage (BAL) cell and protein content in WT, but not iNOS −/− mice. This correlated with expression of Ym1, a marker of oxidative stress in alveolar macrophages and epithelial cells. In contrast, in iNOS −/− mice, Ym1 was only observed 14 days post-exposure in enlarged alveolar macrophages, suggesting that they are alternatively activated. This is supported by findings that lung tumor necrosis factor and lipocalin Lcn2 expression, mediators involved in tissue repair were also upregulated at this time in iNOS −/− mice. Conversely, CEES-induced increases in the proinflammatory genes, monocyte chemotactic protein-1 and cyclooxygenase-2, were abrogated in iNOS −/− mice. In WT mice, CEES treatment also resulted in increases in total lung resistance and decreases in compliance in response to methacholine, effects blunted by loss of iNOS. These data demonstrate that RNS, generated via iNOS play a role in the pathogenic responses to CEES, augmenting oxidative stress and inflammation and suppressing tissue repair. Elucidating inflammatory mechanisms mediating vesicant-induced lung injury is key to the development of therapeutics to treat mustard poisoning. -- Highlights: ► Lung injury, inflammation and oxidative stress are induced by the model vesicant CEES ► RNS generated via iNOS are important in the CEES-induced pulmonary toxicity ► iNOS −/− mice are protected from CEES-induced lung toxicity and

  18. Role of reactive nitrogen species generated via inducible nitric oxide synthase in vesicant-induced lung injury, inflammation and altered lung functioning

    International Nuclear Information System (INIS)

    Pulmonary toxicity induced by sulfur mustard and related vesicants is associated with oxidative stress. In the present studies we analyzed the role of reactive nitrogen species (RNS) generated via inducible nitric oxide synthase (iNOS) in lung injury and inflammation induced by vesicants using 2-chloroethyl ethyl sulfide (CEES) as a model. C57Bl/6 (WT) and iNOS −/− mice were sacrificed 3 days or 14 days following intratracheal administration of CEES (6 mg/kg) or control. CEES intoxication resulted in transient (3 days) increases in bronchoalveolar lavage (BAL) cell and protein content in WT, but not iNOS −/− mice. This correlated with expression of Ym1, a marker of oxidative stress in alveolar macrophages and epithelial cells. In contrast, in iNOS −/− mice, Ym1 was only observed 14 days post-exposure in enlarged alveolar macrophages, suggesting that they are alternatively activated. This is supported by findings that lung tumor necrosis factor and lipocalin Lcn2 expression, mediators involved in tissue repair were also upregulated at this time in iNOS −/− mice. Conversely, CEES-induced increases in the proinflammatory genes, monocyte chemotactic protein-1 and cyclooxygenase-2, were abrogated in iNOS −/− mice. In WT mice, CEES treatment also resulted in increases in total lung resistance and decreases in compliance in response to methacholine, effects blunted by loss of iNOS. These data demonstrate that RNS, generated via iNOS play a role in the pathogenic responses to CEES, augmenting oxidative stress and inflammation and suppressing tissue repair. Elucidating inflammatory mechanisms mediating vesicant-induced lung injury is key to the development of therapeutics to treat mustard poisoning. -- Highlights: ► Lung injury, inflammation and oxidative stress are induced by the model vesicant CEES ► RNS generated via iNOS are important in the CEES-induced pulmonary toxicity ► iNOS −/− mice are protected from CEES-induced lung toxicity and

  19. Changes in species richness and composition in European acidic grasslands over the past 70 years: the contribution of cumulative atmospheric nitrogen deposition

    Energy Technology Data Exchange (ETDEWEB)

    Dupre, C.; Ranke, T.; Diekmann, M. [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Stevens, C.J.; Dise, N.B. [Department of Environmental and Geographical Science, Manchester Metropolitan University, Manchester M15 GD (United Kingdom); Bleeker, A. [Department of Air Quality and Climate Change, Energy research Centre of the Netherlands, PO Box 1, 1755 ZG Petten (Netherlands); Peppler-Lisbach, C. [Department of Biology and Environmental Sciences, University of Oldenburg, PO Box 2503, DE-26111 Oldenburg (Germany); Gowing, D.J.G. [The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Dorland, E. [Utrecht University, Institute of Environmental Biology, Section of Landscape Ecology, PO Box 80084, 3508 TB Utrecht (Netherlands); Bobbink, R. [B-WARE Research Centre, Radboud University, PO Box 9010, 6525 ED Nijmegen (Netherlands)

    2010-01-15

    Our study investigates the negative impact of nitrogen (N) deposition on species richness in acidic grasslands, based on a temporal comparison of vegetation data spanning a period of almost 70 years. We compiled a large data base of plots assigned to the Violion caninae grassland type, composed of managed, but unfertilized semi-natural grasslands on nutrient-poor, acidic soils. In total 1114 plots, mainly from Great Britain, the Netherlands and Germany, were compiled, dating back to 1939. Environmental site information included geographical and soil (mean Ellenberg values) variables as well as estimates of cumulative N and sulphur (S) deposition since 1939. Statistical analyses were carried out separately for the data subsets from the three regions. In all regions, the vegetation differentiation was mainly related to soil acidity and nutrient availability, as well as to the year of sampling and the cumulative amounts of N and S deposition. Plot-species richness of vascular plants and bryophytes (analysed for Great Britain only) decreased with time and analyses suggest these are affected by various factors, notably soil pH, but also latitude and cumulative N deposition. The latter explained more of the variation in species number than the year of sampling and cumulative S deposition, which supports the interpretation that the decline in species richness is mainly caused by increasing N availability and less by altered management and soil acidification. For Great Britain and Germany, cumulative N deposition showed a strong negative relationship with several biodiversity measures, especially the proportion of dicots, whereas it was positively related to the proportion of grass species. In general, our results give temporal evidence for the negative effect of N deposition on species richness in semi-natural vegetation.

  20. Population genomics of the symbiotic plasmids of sympatric nitrogen-fixing Rhizobium species associated with Phaseolus vulgaris.

    Science.gov (United States)

    Pérez Carrascal, Olga M; VanInsberghe, David; Juárez, Soledad; Polz, Martin F; Vinuesa, Pablo; González, Víctor

    2016-09-01

    Cultivated common beans are the primary protein source for millions of people around the world who subsist on low-input agriculture, enabled by the symbiotic N2 -fixation these legumes perform in association with rhizobia. Within a single agricultural plot, multiple Rhizobium species can nodulate bean roots, but it is unclear how genetically isolated these species remain in sympatry. To better understand this issue, we sequenced and compared the genomes of 33 strains isolated from the rhizosphere and root nodules of a particular bean variety grown in the same agricultural plot. We found that the Rhizobium species we observed coexist with low genetic recombination across their core genomes. Accessory plasmids thought to be necessary for the saprophytic lifestyle in soil show similar levels of genetic isolation, but with higher rates of recombination than the chromosomes. However, the symbiotic plasmids are extremely similar, with high rates of recombination and do not appear to have co-evolved with the chromosome or accessory plasmids. Therefore, while Rhizobium species are genetically isolated units within the microbial community, a common symbiotic plasmid allows all Rhizobium species to engage in symbiosis with the same host in a single agricultural plot. PMID:27312778

  1. Preparation of TiO2-nitrogen-doped photocatalyst active under visible light

    Directory of Open Access Journals (Sweden)

    Beata Wawrzyniak

    2006-01-01

    Full Text Available This study examined the photocatalytic degradation of phenol and azo dyes such as Reactive Red 198 and Direct Green 99 by photocatalysis over amorphous hydrated titanium dioxide (TiO2 · H2O obtained directly from the sulphate technology installation modified in gaseous ammonia atmosphere. The photocatalysts were used in the solution and coated on the glass plate after sandblasting. The highest rate of phenol degradation in the solution was obtained for catalysts calcinated at 700°C (6.5% wt., and the highest rate of dye decolorization was found for catalysts calcinated at 500°C and 600°C (ca. 40%–45%. Some TOC measurements of dye solutions were performed to check the rate of mineralization. On the glass plate, the decomposition of DG99 on TiO2/N 500 contrary to TiO2-P25 proceeded completely after 120 hours of visible light irradiation. The prolongation of the time of irradiation did not enhance DG99 degradation on TiO2-P25. The decomposition of the Direct Green 99 on TiO2/N 500 coated on the glass plate covered with liquid glass took place up to 24 hours of irradiation. The liquid layer on the glass plate which was covered with the photocatalyst reduced its activity. The nitrogen doping during calcinations under ammonia atmosphere is a new way of obtaining a photocatalyst which could have a practical application in water treatment system under broadened solar light spectrum as well as self-cleaning coatings.

  2. Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

    Institute of Scientific and Technical Information of China (English)

    HUANG Wen-Juan; LIU Shi-Zhong; CHU Guo-Wei; ZHANG De-Qiang; LI Yue-Lin; LU Xian-Kai; ZHANG Wei; HUANG Juan; D. OTIENO; Z. H. XU; LIU Ju-Xiu

    2012-01-01

    Soil acid phosphomonoesterase activity (APA) plays a vital role in controlling phosphorus (P) cycling and reflecting the current degree of P limitation Responses of soil APA to elevating nitrogen (N) deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems.A study of responses of soll APA to simulated N deposition was conducted in three succession forests of subtropical China.The three forests include a Masson pine (Pinus massoniana) forest (MPF)—pioneer community,a coniferous and broad-leaved mixed forest (MF)—transition community and a monsoon evergreen broadleaved forest (MEBF)—climax community.Four N treatments were designed for MEBF:control (without N added),low-N (50 kg N ha-1 year-1),and medium-N (100 kg N ha-1 year-1) and high-N (150 kg N ha-1 year-1),and only three N treatments (i.e.,control,low-N,mediun-N) were established for MPF and MF.Results showed that soil APA was highest in MEBF.followed by MPF and MF.Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N trcatments.However,soil APA in MEBF exhibited negative responses to high N additions,indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem.Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.

  3. Influence of Agricultural Activity on Nitrogen Budget in Chinese and Japanese Watersheds

    Institute of Scientific and Technical Information of China (English)

    S. D. KIMURA; K. KURAMOCHI; CAI Zu-Cong; M. SAITO; YAN Xiao-Yuan; R. HATANO; A. HAYAKAWA; K. KOHYAMA; TI Chao-Pu; DENG Mei-Hua; M. HOJITO; S. ITAHASHI

    2012-01-01

    To analyze the effect of agricultural activity on nitrogen (N) budget at the watershed scale,a comparative study was conducted at two Japanese watersheds,the Shibetsu River watershed (SRW) and Upper-Naka River watershed (UNRW),and one Chinese watershed,the Jurong Reservoir watershed (JRW).The total area and the proportion of agricultural area (in parentheses) of the watersheds were 685 (51%),1 299 (21%),and 46 km2 (55%) for SRW,UNRW,and JRW,respectively.The main agricultural land use in SRW was forage grassland,while paddy fields occupied the highest proportion of cropland in UNRW (11% of total area) and JRW (31% of total area).The farmland surplus N was 61,48,and 205 kg N ha-1 year-1 for SRW,UNRW,and JRW,respectively.The total input and output for the whole watershed were 89 and 76,83 and 61,and 353 and 176 kg N ha-1 year-1 for SRW,UNRW,and JRW,respectively.The proportion of discharged N to net anthropogenic N input was 31%,37%,and 1.7% for SRW,UNRW,and JRW,respectively.The two watersheds in Japan showed similar proportions of discharged N to those of previous reports,while the watershed in China (JRW) showed a totally different characteristic compared to previous studies.The high N input in JRW did not increase the amount of discharged N at the outlet of the watershed due to high proportions of paddy fields and water bodies,which was an underestimated N sink at the landscape scale.

  4. Structure and biological activity of chemically modified nisin A species

    NARCIS (Netherlands)

    Rollema, Harry S.; Metzger, Jörg W.; Both, Paula; Kuipers, Oscar P.; Siezen, Roland J.

    1996-01-01

    Nisin, a 34-residue peptide bacteriocin, contains the less common amino acids lanthionine, β-methyllanthionine, dehydroalanine (Dha), and dehydrobutyrine (Dhb). Several chemically modified nisin A species were purified by reverse-phase HPLC and characterized by two-dimensional NMR and electrospray m

  5. Determination of nitrogen in wheat flour through Activation analysis using Fast neutron flux of a Thermal nuclear reactor

    International Nuclear Information System (INIS)

    In this work is done a technical study for determining Nitrogen (protein) and other elements in wheat flour Activation analysis, with Fast neutrons from a Thermal nuclear reactor. Initially it is given an introduction about the basic principles of the methods of analysis. Equipment used in Activation analysis and a brief description of the neutron source (Thermal nuclear reactor). The realized experiments for determining the flux form in the irradiation site, the half life of N-13 and the interferences due to the sample composition are included too. Finally, the obtained results by Activation and the Kjeldahl method are tabulated. (Author)

  6. Visible Light Irradiation-Mediated Drug Elution Activity of Nitrogen-Doped TiO2 Nano tubes

    International Nuclear Information System (INIS)

    We have developed nitrogen-doped TiO2 nano tubes showing photo catalytic activity in the visible light region and have investigated the triggered release of antibiotics from these nano tubes in response to remote visible light irradiation. Scanning electron microscopy (SEM) observations indicated that the structure of TiO2 nano tubes was not destroyed on the conditions of 0.05 and 0.1 M diethanolamine treatment. The results of X-ray photoelectron spectroscopy (XPS) confirmed that nitrogen, in the forms of nitrite (TiO2 ) and nitrogen monoxide (NO), had been incorporated into the TiO2 nano tube surface. A drug-release test revealed that the antibiotic-loaded TiO2 nano tubes showed sustained and prolonged drug elution with the help of polylactic acid. Visible light irradiation tests showed that the antibiotic release from nitrogen-doped nano tubes was significantly higher than that from pure TiO2 nano tubes (ρ ≨ 0.05).

  7. Evaluation of body composition and nitrogen content of renal patients on chronic dialysis as determined by total body neutron activation

    International Nuclear Information System (INIS)

    Total body protein (nitrogen), body cell mass (potassium), fat, and water were measured in 15 renal patients on maintenance hemodialysis (MHD). Total body nitrogen was measured by means of prompt γ neutron activation analysis; total body water was determined with tritium labeled water; total body potassium was measured by whole body counting. The extracellular water was determined by a technique utilizing the measurement of total body chloride and plasma chloride. When compared with corresponding values of a control group of the same age, sex, and height, the protein content, body cell mass, and total body fat of the MHD patients were within the normal range. The only significant change was an increase in the extracellular water/body cell mass ratio in the male MHD patients compared to the control. The lack of significant difference of the nitrogen values of the MHD patients compared to matched controls suggests that dialysis minimizes any residual effects of uremic toxicity or protein-calorie malnutrition. These findings further suggest that there is a need to reevaluate the traditional anthropometric and biochemical standards of nutritional status for MHD patients. It was concluded that it is particularly important to measure protein stores of MHD patients with low protein intake to ascertain nutritional status. Finally, in vivo measurement of total body nitrogen and potassium for determination of body composition provides a simple, direct, and accurate assessment of the nutritional status of MHD patients

  8. CARBONACEOUS, NITROGENOUS AND PHOSPHORUS MATTERS REMOVAL FROM DOMESTIC WASTEWATER BY AN ACTIVATED SLUDGE REACTOR OF NITRIFICATION-DENITRIFICATION TYPE

    OpenAIRE

    MOHAMAD ALI FULAZZAKY

    2009-01-01

    This paper proposes an environmental engineering method based on biotechnology approach as one of the expected solutions that should be considered to implementing the activated sludge for improving the quality of water and living environment, especially to remove the major pollutant elements of domestic wastewater. Elimination of 3 major pollutant elements, i.e., carbon, nitrogen and phosphor containing the domestic wastewater is proposed to carry out biological method of an anoxic-aerobic re...

  9. Activated charcoal with high nitrogen conent and zero chromium, method for obtaining same and multiple uses thereof

    OpenAIRE

    Fuente Alonso, Enrique; Ruiz Bobes, Begoña; Rodríguez Gil, Roberto

    2011-01-01

    [EN] The present invention relates to a novel activated charcoal which is characterised by having high nitrogen content, and to the method for obtaining same from solid industrial waste from vegetable tanning of bovine hides, or from tannin-free non-tanned bovine hide, which has been defatted and dehydrated with acetone, said method including the following steps: grinding up the starting material after drying same if necessary in order to obtain a precursor, subjecting the precursor to thermo...

  10. Carbon and nitrogen - The key to biological activity, diversity and productivity in a Haplic Acrisol

    International Nuclear Information System (INIS)

    Soil organic matter is important because it impacts all soil quality functions. Much less information is available on the dynamics of the residual carbon and nitrogen content and their distribution in continuously cropped arable fields. We described the values of the soil properties, pH, moisture content, organic carbon and total nitrogen considering them to be random variables. We treated their spatial variation as a function of the distance between observations within the study site, a continuously-cropped field dominated by Haplic Acrisols. We discussed the nature and structure of the modeled functions, the semivariograms, and interpreted these in the light of the potential of these soils to sustain agricultural productivity. At these sites there had been no conversion of natural forests to agriculture so the paper does not discuss soil carbon storage for either the regional or global storage. All the properties studied showed spatial non-stationarity for the distances covered, indicating that the variance between pairs of observations increased as separating distances also increased. pH, moisture content and total nitrogen were fitted with the power model whereas the linear model best fitted organic carbon. Total nitrogen had the least nugget variance and pH the highest estimated exponent, α, from the power equations. The soils are highly variable in terms of input or return of organic residue to provide a sink for carbon and nitrogen and the breakdown of these materials as affected by pH, moisture availability and microorganisms. (author)

  11. A miniaturized active sampler for the assessment of personal exposure to nitrogen dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Staimer, Norbert; Delfino, Ralph J. [University of California at Irvine, Epidemiology Division, Department of Medicine, School of Medicine, Irvine, CA (United States); Bufalino, Charles [University of California at Riverside, Center for Environmental Research and Technology, Bourns College of Engineering, Riverside, CA (United States); Fine, Philip M.; Sioutas, Constantinos [University of Southern California, Department of Civil and Environmental Engineering, Los Angeles, CA (United States); Kleinman, Michael T. [University of California at Irvine, Department of Community and Environmental Medicine, School of Medicine, Irvine, CA (United States)

    2005-11-01

    A personalized, miniaturized air sampling system was evaluated to estimate the daily exposure of pediatric asthmatics to nitrogen dioxide (NO{sub 2}). The lightweight device (170 g) uses a sampling pump connected to a solid sorbent tube containing triethanolamine (TEA)-impregnated molecular sieve. The pump is powered by a 9 V battery and samples air over a 24 h period at a collection rate of 0.100 L/min. After exposure, the solid sorbent is removed from the tubes for spectrophotometric analysis (Griess Assay). The lower detection limit of the overall method for NO{sub 2} is 11 {mu}g/m{sup 3}. The linearity, precision and accuracy of the sampler was evaluated. Different NO{sub 2} concentrations generated in the laboratory (range: 50 to 340 {mu}g/m{sup 3}) were simultaneously measured by the TEA tube samplers and colocated continuous chemiluminescent NO{sub x} analyzers (reference method). The coefficient of determination for the laboratory test derived from ordinary linear regression (OLR) was r {sup 2}=0.99 (y{sub OLR}=0.94x-4.58) and the precision 3.6%. Further, ambient NO{sub 2} concentrations in the field (range: 10-120 {mu}g/m{sup 3}) were verified with continuous chemiluminescent monitors next to the active samplers. Reweighted least squares analysis (RLS) based on the least median squares procedure (LMS) resulted in a correlation of r {sup 2}=0.68 for a field comparison in Riverside, CA (y{sub RLS}=1.01x-0.94) and r {sup 2}=0.92 in Los Angeles, CA (y{sub RLS}=1.31x-7.12). The precision of the TEA tube devices was 7.4% (at 20-60 {mu}g/m{sup 3} NO{sub 2}) under outdoor conditions. Data show that the performance of this small active sampling system was satisfactory for measuring environmental concentrations of NO{sub 2} under laboratory and field conditions. It is useful for personal monitoring of NO{sub 2} in environmental epidemiology studies where daily measurements are desired. (orig.)

  12. [Effects of Different Land Uses on Soil Active Organic Carbon and Nitrogen Fractions in Jinyun Mountain].

    Science.gov (United States)

    Qi, Xin; Jiang, Chang-sheng; Hao, Qing-ju; Li, Jian-lin

    2015-10-01

    In this paper, we take Jinyun Mountain where located in Beibei district of Chongqing as the research object and explore the effect of different ways of land use on soil active organic carbon, nitrogen components by collecting the soil samples from 0 to 60 cm depth in subtropical evergreen broad-leaved forest (hereinafter referred to as the forest), abandoned land, orchard, farmland and measuring the content of MBC, MBN, DOC and DON. The research results show that the contents of soil MBC, MBN, DOC, DON are reduced with the increase of soil depth in four types of land using soils. Variance analysis of the single factor shows that four kinds of land uses have no significant difference in the contents of MBC, MBN and DON, but the DOC content of the abandoned land is significantly higher than that of other three kinds. It shows that the different ways of land use have no obvious effects on soil MBC, MBN and DON but the abandonment of slope cropland can significantly increase the content of soil DOC. There is no significant difference among the distribution ratio of MBN, DOC, DON in forest, abandoned land, orchard and farmland within the soil from 0 to 60 cm, but the distribution ratio of slope MBC is significantly higher than that of other three kinds. It means farmland soil organic carbon has a higher biological activity, this could due to the application of green manure, farmland manure and other organic fertilizers. Under different land utilizations, DOC/DON is the highest, MBC/MBN is the second, and SOC/TN is the lowest. It means the biological solidification of dissolved organic matter is the strongest, and the mineralization of soil organic matter is the most obvious. Under the four kinds of land uses, there are the lowest ratios in SOC/TN, MBC/MBN and DOC/DON in the farmland. And all the ratios are less than 20, which suggest that the mineralization of farmland soil organic matter is stronger and it's easy to cause the loss of soil carbon.

  13. Effects of high atmospheric CO2 concentration on root hydraulic conductivity of conifers depend on species identity and inorganic nitrogen source.

    Science.gov (United States)

    Gebauer, Tobias; Bassirirad, Hormoz

    2011-12-01

    We examined root hydraulic conductivity (L(p)) responses of one-year-old seedlings of four conifers to the combined effects of elevated CO2 and inorganic nitrogen (N) sources. We found marked interspecific differences in L(p) responses to high CO2 ranging from a 37% increase in P. abies to a 27% decrease in P. menziesii, but these effects depended on N source. The results indicate that CO2 effects on root water transport may be coupled to leaf area responses under nitrate (NO(3)(-)), but not ammonium (NH(4)(+)) dominated soils. To our knowledge, this is the first study that highlights the role of inorganic N source and species identity as critical factors that determine plant hydraulic responses to rising atmospheric CO2 levels. The results have important implications for understanding root biology in a changing climate and for models designed to predict feedbacks between rising atmospheric CO2, N deposition, and ecohydrology.

  14. Characterization of a stable, major DNA polymerase alpha species devoid of DNA primase activity.

    OpenAIRE

    Kaiserman, H B; Benbow, R. M.

    1987-01-01

    We have purified from Xenopus laevis ovaries a major DNA polymerase alpha species that lacked DNA primase activity. This primase-devoid DNA polymerase alpha species exhibited the same sensitivity as the DNA polymerase DNA primase alpha to BuAdATP and BuPdGTP, nucleotide analogs capable of distinguishing between DNA polymerase delta and DNA polymerase DNA primase alpha. The primase-devoid DNA polymerase alpha species also lacked significant nuclease activity indicative of the alpha-like (rathe...

  15. A Hands-On Activity to Introduce the Effects of Transmission by an Invasive Species

    Science.gov (United States)

    May, Barbara Jean

    2013-01-01

    This activity engages students to better understand the impact of transmission by invasive species. Using dice, poker chips, and paper plates, an entire class mimics the spread of an invasive species within a geographic region. The activity can be modified and conducted at the K-16 levels.

  16. ANTIFUNGAL ACTIVITY OF SOME COLEUS SPECIES GROWING IN NILGIRIS

    OpenAIRE

    P Nilani; Duraisamy, B.; Dhanabal, P.S.; khan, Saleemullah; Suresh, B.; Shankar, V; Kavitha, K.Y.; Syamala, G.

    2006-01-01

    The in vitro antifungal activity of solvent extracts of Coleus forskohlii, Coleus blumei and Coleus barbatus were compared by testing against some pathogenic fungi like Aspergillus niger, Aspergillus fumigatus, Aspergillus ruantii, Proteus vulgaris and Candida albicans. The petroleum ether extract of Coleus forskohlii and Coleus barbatus exhibited significant antifungal activity against all the selected organisms. The extracts of Coleus blumei did not show any significant antifungal activity ...

  17. Benthic fluxes of cadmium, lead, copper and nitrogen species in the northern Adriatic Sea in front of the River Po outflow, Italy.

    Science.gov (United States)

    Zago, C; Capodaglio, G; Ceradini, S; Ciceri, G; Abelmoschi, L; Soggia, F; Cescon, P; Scarponi, G

    2000-02-10

    Trace heavy metal (Cd, Pb and Cu) and nitrogen species (N-NO3, N-NO2 and N-NH4) fluxes between sediment and water were examined for approximately 4 days, in a coastal marine station located in the northern Adriatic Sea in front of the River Po outflow. An in situ benthic chamber, equipped with electronic devices for monitoring and adjustment of oxygen and pH and with a temperature detector, was used. The benthic chamber experiment enabled study of the temporal trend of metals and nutrients when oxygen concentration varied in a controlled environment. Although particular care was devoted to chamber deposition and parameter control, sediment resuspension occurred at the beginning of the experiment and O2 fluctuations were observed during the course of the experiment. Pb concentration was affected by both resuspension and oxic conditions in bottom water, which prevented determination of any reasonable Pb flux value. Cd and Cu, not influenced by oxygen fluctuations, reached an equilibrium phase in a short period with initial positive fluxes from sediment of 0.68 (S.D. = 0.07) and 6.9 (S.D. = 5.6) pmol cm(-2) h(-1), respectively. With regard to nitrogen species, the highest positive flux was that of N-NH4 (10.5, S.D. = 2.4, nmol cm(-2) h(-1)) whose concentration increased in the chamber, while nitrate concentration (initial flux of -5.7, S.D. = 1.5, nmol cm(-2) h(-1)) immediately decreased after the beginning of the experiment. Nitrite concentration was almost constant throughout the experiment and its flux was generally low (initial flux 0.1, S.D. = 0.9, nmol cm(-2) h(-1)). PMID:10696718

  18. Antifungal activity of natural and synthetic amides from Piper species

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Joaquim V.; Oliveira, Alberto de; Kato, Massuo J., E-mail: majokato@iq.usp.b [Universidade de Sao Paulo (IQ/USP), SP (Brazil). Inst. de Quimica; Raggi, Ludmila; Young, Maria C. [Instituto de Botanica, Sao Paulo, SP (Brazil). Secao de Fisiologia e Bioquimica de Plantas

    2010-07-01

    The antifungal leaves extract from Piper scutifolium was submitted to bioactivity-guided chromatographic separation against Cladosporium cladosporioides and C. sphaerospermum yielding piperine, piperlonguminine and corcovadine as the active principles which displayed a detection limit of 1 {mu}g. Structure-activity relationships were investigated with the preparation of twelve analogs having differences in the number of unsaturations, aromatic ring substituents and in the amide moiety. Analogs having a single double-bond and no substituent in the aromatic ring displayed higher activity, while N,N,-diethyl analogs displayed higher dose-dependent activity. (author)

  19. Antifungal activity of natural and synthetic amides from Piper species

    International Nuclear Information System (INIS)

    The antifungal leaves extract from Piper scutifolium was submitted to bioactivity-guided chromatographic separation against Cladosporium cladosporioides and C. sphaerospermum yielding piperine, piperlonguminine and corcovadine as the active principles which displayed a detection limit of 1 μg. Structure-activity relationships were investigated with the preparation of twelve analogs having differences in the number of unsaturations, aromatic ring substituents and in the amide moiety. Analogs having a single double-bond and no substituent in the aromatic ring displayed higher activity, while N,N,-diethyl analogs displayed higher dose-dependent activity. (author)

  20. Antibacterial and antioxidant activity of lichen species Ramalina roesleri.

    Science.gov (United States)

    Sisodia, R; Geol, M; Verma, S; Rani, A; Dureja, P

    2013-01-01

    Solvent extracts of Ramalina roesleri Nyl were assayed for antimicrobial and antioxidant activity. Hexane extract was highly active against Staphylococcus aureus and Streptococcus mutans. The 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity of extracts ranged from 29.42% to 87.90%. Atranorin, protolichesterinic acid, usnic acid, 2-hydroxy-4-methoxy-6-propyl benzoic acid, homosekikaic acid, sekikaic acid, benzoic acid, 2,4-dihydroxy-6-propyl and 2,4-dihydroxy-3,6-dimethyl benzoate were isolated from the hexane extract. Maximum DPPH radical scavenging activity was exhibited by sekikaic acid followed by homosekikaic acid. PMID:23822758

  1. Impact of an invasive nitrogen-fixing tree on arbuscular mycorrhizal fungi and the development of native species

    OpenAIRE

    Guisande-Collazo, Alejandra; González, Luís; Souza-Alonso, Pablo

    2016-01-01

    This study contributes to knowledge on the effect of the invasive N2-fixing tree, Acacia dealbata, on soil microbial communities and consequences on plant species that are dependent on symbiotic relationships as in the case of Plantago lanceolata. The main results of this work indicate that Acacia dealbata modifies the structure of arbuscular mycorrhizal fungi in the invaded shrublands and consequently the growth and development of plants that depend on AMF. Plantago lanceolata showed a subst...

  2. Wetland-based passive treatment systems for gold ore processing effluents containing residual cyanide, metals and nitrogen species

    OpenAIRE

    Álvarez, R.; Ordóñez, A.; Loredo, J; Younger, P.L.

    2013-01-01

    Gold extraction operations generate a variety of wastes requiring responsible disposal in compliance with current environmental regulations. During recent decades, increased emphasis has been placed on effluent control and treatment, in order to avoid the threat to the environment posed by toxic constituents. In many modern gold mining and ore processing operations, cyanide species are of most immediate concern. Given that natural degradation processes are known to reduce the toxicity of cyan...

  3. Leaf life span and nitrogen content in semideciduous forest tree species (Croton priscus and Hymenaea courbaril) Duração da vida da folha e conteúdo de nitrogênio em espécies arbóreas (Croton priscus e Hymenaea courbaril) de floresta semidecídua

    OpenAIRE

    Claudia Regina Baptista Haddad; Damiani Pereira Lemos; Paulo Mazzafera

    2004-01-01

    In comparison to deciduous species, evergreen plants have lower leaf nutrient contents and higher leaf life span, important mechanisms for nutrient economy, allowing the colonization of low fertility soils. Strategies to conserve nitrogen in two semideciduous tropical forest tree species, with different leaf life spans were analyzed. The hypothesis was the fact that the two species would present different nitrogen conservation mechanisms in relation to chemical (total nitrogen, protein, chlor...

  4. Fruit-body production and 137Cs-activity of Cantharellus cibarius after nitrogen and potassium fertilization

    International Nuclear Information System (INIS)

    A study of the possible effect of fertilization with nitrogen and potassium on fruit-body production and 137Cs-activity concentration of Cantharellus cibarius was carried out in a pine forest in the eastern part of central Sweden. Nitrogen, in the form of ammonium nitrate, was added twice, in 1984 and 1990, at a dose of 150 kg N ha-1. Fruit-body production was measured during 1985-1991, and the 137Cs-activity concentration during 1988-1991. Fruit-body production showed a pronounced variation between years. The ratio between the highest annual production and the lowest was about 20. No statistically significant effects of either the fertilization treatments on production were observed. However, nitrogen fertilization showed a tendency towards a decrease in production by about 30%. The field site is situated in an area substantially affected by the fallout from the Chernobyl accident in 1986. The fruit-bodies on the site had a clearly elevated activity concentration of 137Cs, which averaged 15 Bq q-1 d.m. for all plots and years. On the 4.5 ha study site, the 137Cs-activity concentration varied by a factor of 10 between individual plots. The year with the highest fruit-body production had the lowest 137Cs-activity concentration. The fertilizations lacked statistically significant effect in 137Cs-activity concentration, but a 50% reduction was indicated for potassium fertilization causing the concentration to fall below the Swedish health limit for human food. 31 refs, 3 figs

  5. Aromatic plants play an important role in promoting soil biological activity related to nitrogen cycling in an orchard ecosystem.

    Science.gov (United States)

    Chen, Xinxin; Song, Beizhou; Yao, Yuncong; Wu, Hongying; Hu, Jinghui; Zhao, Lingling

    2014-02-15

    Aromatic plants can substantially improve the diversity and structure of arthropod communities, as well as reduce the number of herbivore pests and regulate the abundance of predators and parasitoids. However, it is not clear whether aromatic plants are also effective in improving soil quality by enhancing nutrient cycling. Here, field experiments are described involving intercropping with aromatic plants to investigate their effect on soil nitrogen (N) cycling in an orchard ecosystem. The results indicate that the soil organic nitrogen and available nitrogen contents increased significantly in soils intercropped with aromatic plants. Similarly, the activities of soil protease and urease increased, together with total microbial biomass involved in N cycling, including nitrifying bacteria, denitrifying bacteria and azotobacters, as well as the total numbers of bacteria and fungi. This suggests that aromatic plants improve soil N cycling and nutrient levels by enriching the soil in organic matter through the regulation of both the abundance and community structure of microorganisms, together with associated soil enzyme activity, in orchard ecosystems.

  6. Comparison of active and passive optical sensors for assessment of plant nitrogen

    Science.gov (United States)

    Nitrogen (N) fertilizer has received attention for a long time as a potential source of ground water pollution. Considerable research has been conducted to investigate use of remote sensing for assessing plant N status to improve N use efficiency. Most of these studies have used passive type sensors...

  7. Nitrogen determination in wheat by neutron activation analysis using fast neutron flux from a thermal nuclear reactor

    International Nuclear Information System (INIS)

    This is a study of the technique for the determination of nitrogen and other elements in wheat flour through activation analysis with fast neutrons from a thermal nuclear reactor. The study begins with an introduction about the basis of the analytical methods, the equipment used in activation analysis and a brief description of the neutrons source. In the study are included the experiments carried out in order to determine the flux form in the site of irradiation, the N-13 half life and the interference due to the sample composition. (author)

  8. Chlordane components and metabolites in seven species of Arctic seabirds from the Northwater Polynya: relationships with stable isotopes of nitrogen and enantiomeric fractions of chiral components.

    Science.gov (United States)

    Fisk, A T; Moisey, J; Hobson, K A; Karnovsky, N J; Norstrom, R J

    2001-01-01

    The Northwater Polynya (NOW) is a large area of year-round open water found in the high Arctic between Ellesmere Island and Greenland. NOW has high biological productivity compared with other arctic marine areas, and supports large populations of several seabird species. Seven species of seabirds, dovekie (Alle alle, DOVE), thick-billed murre (Uria lomvia, TBMU), black guillemot (Cepphus grylle, BLGU), black-legged kittiwake (Rissa tridactyla, BLKI), ivory gull (Pagophila eburnea, IVGU), glaucous gull (Larus hyperboreus, GLGU) and northern fulmar (Fulmaris glacialis, NOFU) were collected in May and June 1998 to determine chlordane concentrations in liver and fat and to examine species differences, relationships with stable isotopes of nitrogen, and enantiomeric fractions (EFs) of chiral components. sigma CHLOR concentrations varied over an order of magnitude among species, from a low of 176 +/- 19 ng/g (lipid corrected) in TMBU liver to a high of 3190 +/- 656 ng/g (lipid corrected) in NOFU liver. Lipid-corrected concentrations of chlordane did not vary between sex for any species or between fat and liver except for the DOVE, that had fat concentrations that were significantly greater than the liver. delta 15N values described a significant percentage of the variability of concentrations for most chlordane components, although less than what has been reported for whole food chains. Slopes of delta 15N versus concentration of chlordane components and sigma CHLOR were similar with the exception of those which were metabolized (trans-chlordane) or formed through biotransformation (oxychlordane). The relative proportions of chlordane components in seabirds were related to phylogeny; the procellariid (NOFU) had the greatest percentage of oxychlordane (> 70%), followed by the larids (BLKI, IVGU and GLGU; 40-50%) and the alcids (DOVE and BLGU; 10-20%). The exception was TBMU, an alcid, where oxychlordane made up > 40% of its chlordane. EFs of chiral components failed to

  9. Improving high temperature creep resistance of reduced activation steels by addition of nitrogen and intermediate heat treatment

    Science.gov (United States)

    Liu, W. B.; Zhang, C.; Xia, Z. X.; Yang, Z. G.

    2014-12-01

    In the present study, we report an enhanced high-temperature creep resistance in reduced activation ferrite/martensite (RAFM) steels, by introducing nitrogen (0.035 wt%, M3 steel) and employing a novel intermediate heat treatment I-Q-T (intermediate treatment, quenching and tempering). In comparison with all the control groups, the uniaxial tests of the I-Q-T treated M3 steel showed significant increase in rupture time and decrease in elongation. The microstructures of the samples were further characterized to elucidate the origin of the enhanced creep resistance. It is found that, by introducing nitrogen, the primary TaC particles were refined; by employing the I-Q-T heat treatment, the dispersed fine secondary MX precipitates, as well as the lath subgrains containing high-density dislocations, were increased: all are responsible for the improved creep resistance.

  10. Antimicrobial activity in vitro of plumbagin isolated from Plumbago species

    OpenAIRE

    Selma Ribeiro de Paiva; Maria Raquel Figueiredo; Tânia Verônica Aragão; Maria Auxiliadora Coelho Kaplan

    2003-01-01

    Plumbagin is a naturally occurring naphthoquinone isolated from roots of Plumbago scandens. The plant was collected at the Campus of Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. P. scandens is used as a traditional medicine for the treatment of several diseases. The antimicrobial activity of plumbagin was evaluated using the macrodilution method. The compound exhibited relatively specific activity against bacteria and yeast. The minimum inhibitory concentration test showed the growth inhibi...

  11. In vivo activity of aryl ozonides against Schistosoma species.

    Science.gov (United States)

    Keiser, Jennifer; Ingram, Katrin; Vargas, Mireille; Chollet, Jacques; Wang, Xiaofang; Dong, Yuxiang; Vennerstrom, Jonathan L

    2012-02-01

    We evaluated the in vivo antischistosomal activities of 11 structurally diverse synthetic peroxides. Of all compounds tested, ozonide (1,2,4-trioxolane) OZ418 had the highest activity against adult Schistosoma mansoni, with total and female worm burden reductions of 80 and 90% (P < 0.05), respectively. Furthermore, treatment of S. haematobium-infected mice with OZ418 reduced the total worm burden by 86%. In conclusion, OZ418 is a promising antischistosomal lead compound. PMID:22106214

  12. In Vivo Activity of Aryl Ozonides against Schistosoma Species

    OpenAIRE

    Keiser, Jennifer; Ingram, Katrin; Vargas, Mireille; Chollet, Jacques; Wang, Xiaofang; Dong, Yuxiang; Vennerstrom, Jonathan L.

    2012-01-01

    We evaluated the in vivo antischistosomal activities of 11 structurally diverse synthetic peroxides. Of all compounds tested, ozonide (1,2,4-trioxolane) OZ418 had the highest activity against adult Schistosoma mansoni, with total and female worm burden reductions of 80 and 90% (P < 0.05), respectively. Furthermore, treatment of S. haematobium-infected mice with OZ418 reduced the total worm burden by 86%. In conclusion, OZ418 is a promising antischistosomal lead compound.

  13. Preparation of porous nitrogen-doped titanium dioxide microspheres and a study of their photocatalytic, antibacterial and electrochemical activities

    International Nuclear Information System (INIS)

    Graphical abstract: Porous N-doped TiO2 microspheres were prepared for the first time via plasma technique. The sample exhibited better photocatalytic activity, photoinduced inactivation activity and better electrochemical activity than those of TiO2 microspheres and P25. Display Omitted Highlights: ► Porous N-doped TiO2 microspheres were prepared via nitrogen plasma technique. ► Plasma treatment did not affect the porous structure of the TiO2 microspheres. ► With the plasma treatment, the N contents in the samples increased. ► Their photocatalytic, antibacterial and electrochemical activities were studied. -- Abstract: Nitrogen-doped titanium dioxide (N-doped TiO2) microspheres with porous structure were prepared via the nitrogen-assisted glow discharge plasma technique at room temperature for the first time. The samples were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption–desorption measurement, UV–Vis diffuse reflectance spectra, photoluminescence spectroscopy and X-ray photoelectron spectroscopy. The results indicated that the plasma treatment did not affect the porous structure of the TiO2 microspheres. With the plasma treatment, the N contents in the samples increased. During the photocatalytic degradation of methylene blue under simulative sunlight irradiation, the sample after plasma treatment for 60 min (N-TiO2-60) exhibited higher photocatalytic activity than those of the TiO2 microspheres, P25 and other N-doped TiO2 microspheres. Furthermore, the N-TiO2-60 showed excellent antibacterial activities towards Escherichia coli under visible irradiation. These should be attributed to the enhancement of the visible light region absorption for TiO2 after N-doping. Electrochemical data demonstrated that the N-doping not only enhanced the electrochemical activity of TiO2, but also improved the reversibility of Li insertion/extraction reactions and the rate behavior of TiO2 during charge–discharge cycles.

  14. ACTIVITIES OF AMMONIA ASSIMILATION ENZYMES AS INDICATORS OF THE RELATIVE SUPPLY OF NITROGEN SUBSTRATES FOR MARINE BACTERIOPLANKTON IN SUB-TROPICAL COASTAL WATER

    Science.gov (United States)

    The supply of nitrogen substrates available for bacterial production in seawater was determined using the activities of ammonia assimilation enzymes, glutamine synthetase (GS) and glutamate dehydrogenase (GDH). Expression of GS and GDH by bacteria in pure culture is generally ind...

  15. Nitrogen and phosphorus uptake rates of different species from a coral reef community after a nutrient pulse

    Science.gov (United States)

    den Haan, Joost; Huisman, Jef; Brocke, Hannah J.; Goehlich, Henry; Latijnhouwers, Kelly R. W.; van Heeringen, Seth; Honcoop, Saskia A. S.; Bleyenberg, Tanja E.; Schouten, Stefan; Cerli, Chiara; Hoitinga, Leo; Vermeij, Mark J. A.; Visser, Petra M.

    2016-06-01

    Terrestrial runoff after heavy rainfall can increase nutrient concentrations in waters overlying coral reefs that otherwise experience low nutrient levels. Field measurements during a runoff event showed a sharp increase in nitrate (75-fold), phosphate (31-fold) and ammonium concentrations (3-fold) in waters overlying a fringing reef at the island of Curaçao (Southern Caribbean). To understand how benthic reef organisms make use of such nutrient pulses, we determined ammonium, nitrate and phosphate uptake rates for one abundant coral species, turf algae, six macroalgal and two benthic cyanobacterial species in a series of laboratory experiments. Nutrient uptake rates differed among benthic functional groups. The filamentous macroalga Cladophora spp., turf algae and the benthic cyanobacterium Lyngbya majuscula had the highest uptake rates per unit biomass, whereas the coral Madracis mirabilis had the lowest. Combining nutrient uptake rates with the standing biomass of each functional group on the reef, we estimated that the ammonium and phosphate delivered during runoff events is mostly taken up by turf algae and the two macroalgae Lobophora variegata and Dictyota pulchella. Our results support the often proposed, but rarely tested, assumption that turf algae and opportunistic macroalgae primarily benefit from episodic inputs of nutrients to coral reefs.

  16. Effects of reactive oxygen and nitrogen species induced by ammonium dinitramide decomposition in aqueous solutions of deoxyribose nucleic acid.

    Science.gov (United States)

    Steel-Goodwin, L; Kuhlman, K J; Miller, C; Pace, M D; Carmichael, A J

    1997-01-01

    Ammonium dinitramide (ADN), a potential rocket fuel, decomposes in water forming NO2. The chemistry of this ADN-released NO2 in oxygenated biological systems is complex both in the number of potential chemical species and in the number of parallel and consecutive reactions that can theoretically occur. High-pressure liquid chromatography (HPLC) studies revealed ADN fragmented deoxyribose nucleic acid (DNA). Damage to DNA standard solutions was caused by at least two major pathways, one arising from reactions of NO2 with oxygen and one arising from a reaction with superoxide (O2-.). The radical species generated when ADN is incubated with standard solutions of DNA, pH 7.5, in the presence of the spin trap agent n-tert-butyl-alpha-nitrone (PBN) was compared with the PBN-radical adducts generated in the presence of ADN and O2-. or of ADN and hydrogen peroxide (H2O2). The ADN-induced PBN radical adducts increased linearly over the 90-minute study period. The values of peak intensity in the presence of O2-. and in the presence of H2O2, were 828% and 7.08%, respectively, of the ADN-induced radicals alone. The synergistic effect of ADN with O2- may provide an understanding of the sensitivity of the rat blastocyst to aDN at the preimplantation stage of development and the lack of toxicity in in vivo studies in tissues high in catalase. PMID:9142377

  17. VISUALIZATION OF BIOCHEMICAL ACTIVITY OF MICROORGANISMS GENUS AEROCOCCUS SPECIES AEROCOCCUS VIRIDANS

    Directory of Open Access Journals (Sweden)

    Stepansky DO

    2016-03-01

    Full Text Available Introduction. Aerococci are catalase-negative Gram-positive microorganisms, widespread in the environment, in the cold-blooded microbiocenoses [1, 2] and warm-blooded organisms [3]. Currently, there are seven species of the Aerococcus genus [4]. Type A. viridans got its name as a result of greening blood agar around the growing colonies. It was found that one of the products of A. viridans growth is hydrogen peroxide, has an antagonistic effect on various kinds of bacteria "in vitro" and "in vivo" [5]. It was subsequently found that hydrogen peroxide and superoxide radical are produced as a result of NAD-independent lactatoxidase [6,7] and piruvatoxidase functioning[8]. The oxidative ability of A. viridans is a distinctive feature and allows to visualize these properties using a specific indicator medium [9]. We have developed an indicator that enables to visualize oxidation and reduction properties of aerococci. Material & methods. Auto-symbiotic cultures of A. viridans was used for studying of oxidase - reductase activity, inoculated from human body, an industrial strain of A. viridans 167, used for the preparation of "A-bacterin", culture of Aureobasidium pullulans B5, isolated from the soil and having glucose oxidase activity [10]. Designed indicating medium were also tested in the inoculation of aerococci crops, having lactatoxidase activity of biomaterials from birds and mammals. As a basis for the indicating media (IM IM1 media was selected with following composition (g per 1 liter of water Iodide / potassium 26.0 Soluble starch 10.0 Nutrient agar 30.0 For visualization of oxidase-reductase activity of aerococci acellular components IM4 was developed based on IM3, in which distilled water after double purification was used instead of tap water and highly purified agar-agar was used instead of standard nutrient agar. Results & discussion. IM1 is used to test the oxidative properties of aerococci crops. IM manifests the appearance of a dark

  18. Involvement of Nitrogen on Flavonoids, Glutathione, Anthocyanin, Ascorbic Acid and Antioxidant Activities of Malaysian Medicinal Plant Labisia pumila Blume (Kacip Fatimah

    Directory of Open Access Journals (Sweden)

    Zaharah Abdul Rahman

    2011-12-01

    Full Text Available A split plot 3 by 4 experiment was designed to characterize the relationship between production of gluthatione (GSH, oxidized gluthatione (GSSG, total flavonoid, anthocyanin, ascorbic acid and antioxidant activities (FRAP and DPPH in three varieties of Labisia pumila Blume, namely the varieties alata, pumila and lanceolata, under four levels of nitrogen fertilization (0, 90, 180 and 270 kg N/ha for 15 weeks. The treatment effects were solely contributed by nitrogen application; there was neither varietal nor interaction effects observed. As the nitrogen levels decreased from 270 to 0 kg N/ha, the production of GSH and GSSG, anthocyanin, total flavonoid and ascorbic acid increased steadily. At the highest nitrogen treatment level, L. pumila exhibited significantly lower antioxidant activities (DPPH and FRAP than those exposed to limited nitrogen growing conditions. Significant positive correlation was obtained between antioxidant activities (DPPH and FRAP, total flavonoid, GSH, GSSG, anthocyanin and ascorbic acid suggesting that an increase in the antioxidative activities in L. pumila under low nitrogen fertilization could be attributed to higher contents of these compounds. From this observation, it could be concluded that in order to avoid negative effects on the quality of L. pumila, it is advisable to avoid excessive application of nitrogen fertilizer when cultivating the herb for its medicinal use.

  19. Involvement of nitrogen on flavonoids, glutathione, anthocyanin, ascorbic acid and antioxidant activities of Malaysian medicinal plant Labisia pumila Blume (Kacip Fatimah).

    Science.gov (United States)

    Ibrahim, Mohd Hafiz; Jaafar, Hawa Z E; Rahmat, Asmah; Rahman, Zaharah Abdul

    2012-01-01

    A split plot 3 by 4 experiment was designed to characterize the relationship between production of gluthatione (GSH), oxidized gluthatione (GSSG), total flavonoid, anthocyanin, ascorbic acid and antioxidant activities (FRAP and DPPH) in three varieties of Labisia pumila Blume, namely the varieties alata, pumila and lanceolata, under four levels of nitrogen fertilization (0, 90, 180 and 270 kg N/ha) for 15 weeks. The treatment effects were solely contributed by nitrogen application; there was neither varietal nor interaction effects observed. As the nitrogen levels decreased from 270 to 0 kg N/ha, the production of GSH and GSSG, anthocyanin, total flavonoid and ascorbic acid increased steadily. At the highest nitrogen treatment level, L. pumila exhibited significantly lower antioxidant activities (DPPH and FRAP) than those exposed to limited nitrogen growing conditions. Significant positive correlation was obtained between antioxidant activities (DPPH and FRAP), total flavonoid, GSH, GSSG, anthocyanin and ascorbic acid suggesting that an increase in the antioxidative activities in L. pumila under low nitrogen fertilization could be attributed to higher contents of these compounds. From this observation, it could be concluded that in order to avoid negative effects on the quality of L. pumila, it is advisable to avoid excessive application of nitrogen fertilizer when cultivating the herb for its medicinal use. PMID:22312260

  20. Effects of grass species and grass growth on atmospheric nitrogen deposition to a bog ecosystem surrounded by intensive agricultural land use

    Science.gov (United States)

    Hurkuck, Miriam; Brümmer, Christian; Mohr, Karsten; Spott, Oliver; Well, Reinhard; Flessa, Heinz; Kutsch, Werner L

    2015-01-01

    We applied a 15N dilution technique called “Integrated Total Nitrogen Input” (ITNI) to quantify annual atmospheric N input into a peatland surrounded by intensive agricultural practices over a 2-year period. Grass species and grass growth effects on atmospheric N deposition were investigated using Lolium multiflorum and Eriophorum vaginatum and different levels of added N resulting in increased biomass production. Plant biomass production was positively correlated with atmospheric N uptake (up to 102.7 mg N pot−1) when using Lolium multiflorum. In contrast, atmospheric N deposition to Eriophorum vaginatum did not show a clear dependency to produced biomass and ranged from 81.9 to 138.2 mg N pot−1. Both species revealed a relationship between atmospheric N input and total biomass N contents. Airborne N deposition varied from about 24 to 55 kg N ha−1 yr−1. Partitioning of airborne N within the monitor system differed such that most of the deposited N was found in roots of Eriophorum vaginatum while the highest share was allocated in aboveground biomass of Lolium multiflorum. Compared to other approaches determining atmospheric N deposition, ITNI showed highest airborne N input and an up to fivefold exceedance of the ecosystem-specific critical load of 5–10 kg N ha−1 yr−1. PMID:26257870

  1. Polyphenols of Camellia sinenesis decrease mortality, hepatic injury and generation of cytokines and reactive oxygen and nitrogen species after hemorrhage/resuscitation in rats

    Directory of Open Access Journals (Sweden)

    Lehnert Mark

    2010-08-01

    Full Text Available Abstract Background Reactive oxygen species (ROS and reactive nitrogen species (RNS are produced during hemorrhagic shock and resuscitation (H/R, which may contribute to multiple organ failure. The Aim of this study was to test the hypothesis that green tea (Camellia sinenesis extract containing 85% polyphenols decreases injury after H/R in rats by scavenging ROS and RNS. Methods Female Sprague Dawley rats were given 100 mg polyphenol extract/kg body weight or vehicle 2 h prior to hemorrhagic shock. H/R was induced by two protocols: 1 withdrawal of blood to a mean arterial pressure of 40 mm Hg followed by further withdrawals to decrease blood pressure progressively to 28 mm Hg over 1 h (severe, and 2 withdrawal of blood to a sustained hypotension of 40 mm Hg for 1 h (moderate. Rats were then resuscitated over 1 h with 60% of the shed blood volume plus twice the shed blood volume of lactated Ringer's solution. Serum samples were collected at 10 min and 2 h after resuscitation. At 2 or 18 h, livers were harvested for cytokine and 3-nitrotyrosine quantification, immunohistochemical detection of 4-hydroxynonenol (4-HNE and inducible nitric oxide synthase (iNOS protein expression. Results After severe H/R, 18-h survival increased from 20% after vehicle to 70% after polyphenols (p Conclusion Polyphenols decrease ROS/RNS formation and are beneficial after hemorrhagic shock and resuscitation.

  2. Dynamics of nitrogen nutrition of coexisting dominant trees in mixed broad-leaved/Korean pine forest

    Institute of Scientific and Technical Information of China (English)

    Li Yuwen

    1999-01-01

    Chemical analysis of ammonium, nitrate and total nitrogen in tree leaves and roots and an in-vivo bioassay for nitrate reductase activity (NRA) were used to monitor the seasonal variations in nitrogen assimilation among four coexisting dominant tree species, including Pinus koraiensis, Ti/ia amurensis, Fraxinus mandshurica and Acer mono, in a virgin mixed broad-leaved/Korean pine (Pinus koraiensis) forest. The soil study included individual horizons of L+F (0-5 cm), Ah (5-11 cm) and Aw (11-25 cm). All four species had nitrate and ammonium in their roots and leaves, and also NRA in leaves. This indicated that these coexisting species were adapted to ammonium + nitrate nutrition. A negative correlation existed between nitrate use and ammonium use. Ammonium concentration was higher than that of nitrate in tree leaves and roots, and also in soils, which indicated climax woody species had a relative preference for ammonium nutrition. There was a positive relationship between tree nitrogen nutrition use and soil nitrogen nutrient supply. Utilization of ammonium and nitrate as well as the seasonal patterns differed significantly between the species. Peaks of ammonium, nitrate, NRA and total nitrogen in one species were therefore not necessarily synchronous with peaks in other species, and which indicated a species-specific seasonal use of nitrogen. The species-specific temporal differentiation in nitrogen use might reduce the competition between co-existing species and may be an important mechanism promoting stability of virgin mixed broad-leaved∥Korean pine forest.

  3. Azotobacter vinelandii NIFL is a flavoprotein that modulates transcriptional activation of nitrogen-fixation genes via a redox-sensitive switch.

    OpenAIRE

    Hill, S.; Austin, S; Eydmann, T.; Jones, T.; Dixon, R

    1996-01-01

    The NIFL regulatory protein controls transcriptional activation of nitrogen fixation (nif) genes in Azotobacter vinelandii by direct interaction with the enhancer binding protein NIFA. Modulation of NIFA activity by NIFL, in vivo occurs in response to external oxygen concentration or the level of fixed nitrogen. Spectral features of purified NIFL and chromatographic analysis indicate that it is a flavoprotein with FAD as the prosthetic group, which undergoes reduction in the presence of sodiu...

  4. Potential pancreatic lipase inhibitory activity of an endophytic Penicillium species.

    Science.gov (United States)

    Gupta, Mahiti; Saxena, Sanjai; Goyal, Dinesh

    2015-02-01

    Pancreatic lipase (PL) is considered as one of the safest target for diet-induced anti-obesity drug development. Orlistat is the only PL inhibitor approved for anti-obesity treatment till date. In the process of exploration of new PL inhibitors, we have screened culture filtrates of 70 endophytic fungi of medicinal plants using qualitative as well as quantitative in-vitro PL assays. The qualitative assays indicated potential PL inhibition in only three isolates, namely #57 TBBALM, #33 TBBALM and #1 CSSTOT. Only ethyl acetate extracts of the culture filtrates of these isolates exhibited the PL inhibition. #57 TBBLAM ethyl acetate extract of culture filtrate exhibited potential PL inhibition with an IC50 of 3.69 µg/ml which was comparable to the positive control, i.e. Orlistat exhibiting IC50 value of 2.73 µg/ml. Further molecular phylogenetic tools and morphological studies were used to identify the isolate #57 TBBALM as Penicillium species. PMID:24417211

  5. Growth enhancement and gene expression of Arabidopsis thaliana irradiated with active oxygen species

    Science.gov (United States)

    Watanabe, Satoshi; Ono, Reoto; Hayashi, Nobuya; Shiratani, Masaharu; Tashiro, Kosuke; Kuhara, Satoru; Inoue, Asami; Yasuda, Kaori; Hagiwara, Hiroko

    2016-07-01

    The characteristics of plant growth enhancement effect and the mechanism of the enhancement induced by plasma irradiation are investigated using various active species in plasma. Active oxygen species in oxygen plasma are effective for growth enhancement of plants. DNA microarray analysis of Arabidopsis thaliana indicates that the genes coding proteins that counter oxidative stresses by eliminating active oxygen species are expressed at significantly high levels. The size of plant cells increases owing to oxygen plasma irradiation. The increases in gene expression levels and cell size suggest that the increase in the expression level of the expansin protein is essential for plant growth enhancement phenomena.

  6. Antimicrobial activity in vitro of plumbagin isolated from Plumbago species

    Directory of Open Access Journals (Sweden)

    Selma Ribeiro de Paiva

    2003-10-01

    Full Text Available Plumbagin is a naturally occurring naphthoquinone isolated from roots of Plumbago scandens. The plant was collected at the Campus of Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. P. scandens is used as a traditional medicine for the treatment of several diseases. The antimicrobial activity of plumbagin was evaluated using the macrodilution method. The compound exhibited relatively specific activity against bacteria and yeast. The minimum inhibitory concentration test showed the growth inhibiton of Staphylococcus aureus at a concentration of 1.56 µg/ml and of Candida albicans at a concentration of 0.78 µg/ml. These results suggest the naphthoquinone plumbagin as a promising antimicrobial agent.

  7. In vivo studies on the nitrogen, chlorine, calcium and phosphorus composition of rats by neutron activation analysis

    International Nuclear Information System (INIS)

    The role of neutron activation analysis 'in vivo' to determine the elementary composition of the rat organism is demonstrated. In part one the possibilities offered by certain methods which establish the elementary composition of living organisms are analyzed, together with the contribution and scope of neutron activation analysis. In part two the technical details of the neutron activation of rats in vivo are determined and the problems raised by application of the method considered. This is followed by an application of neutron activation analysis to research on changes in the nitrogen, chlorine, calcium and phosphorus composition of rats during growth (from 30 to 440 days) and important biological events such as puberty in both sexes, reproduction and lactation. Finally a study of the fertility rate and the effects of repeated irradiations on Sprague-Dawley rats are described

  8. UGT Xenobiotic metabolizing activity and genetic evolution in Pinniped species

    OpenAIRE

    Kakehi, Mayu; IKENAKA, Yoshinori; Nakayama, Shouta M. M.; Kawai, Yusuke K.; Watanabe, Kensuke P.; Mizukawa, Hazuki; Nomiyama, Kei; Tanabe, Shinsuke; Ishizuka, Mayumi

    2015-01-01

    There are various interspecies differences in xenobiotic-metabolizing enzymes. It is known that cats show slow glucuronidation of drugs such as acetaminophen and strong side effects due to the UGT1A6 pseudogene. Recently, the UGT1A6 pseudogene was found in the Northern elephant seal and Otariidae was suggested to be UGT1A6-deficient. From the results of measurements of uridine diphosphate-glucuronosyltransferase (UGT) activity using liver microsomes, the Steller sea lion, Northern fur seal, a...

  9. Light Pollution: Impact on Voice Activity of Selected Bird Species

    OpenAIRE

    Plzenská, Markéta

    2013-01-01

    The urban environment differs from the natural environment of birds in many aspects, which cause modifications of singing activites of urban bird populations. Some scientific studies have demonstrated that males begin to vocalize earlier before dawn in the noisy urban habitats than those inhabiting thein natural forest biotope. The effects of light pollution on bird voice activity has not been studied yet, although this factor may also cause some changes in the course of bird vocalization. Th...

  10. Investigation of Cytotoxic Activity in Four Stachys Species from Iran

    Science.gov (United States)

    Khanavi, Mahnaz; Manayi, Azadeh; Lotfi, Mahnaz; Abbasi, Rofeyde; Majdzadeh, Maryam; Ostad, Seyed Nasser

    2012-01-01

    The aerial parts of Stachys laxa Boiss. and Buhse. from Siah-bishe in Mazandaran province, Stachys trinervis Aitch. and Hemsl. from Karaj in Alborz province, Stachys subaphylla Rech. F. and Stachys turcomanica Trautv. from Golestan province have been collected in May 2008. Total extracts were obtained through MeOH/H2O (80/20) and then partitioned between CHCl3, EtOAc and MeOH. These fractions and total extracts have been investigated for in-vitro cytotoxic activity against the colon carcinoma (HT-29), colorectal adenocarcinoma (Caco-2), breast ductal carcinoma (T47D) and Swiss mouse embryo fibroblast (NIH 3T3) cell lines using MTT assay (3-(4,5-di methyl thiazol-2-yl)-2,5-di phenyltetrazolium bromide). At each cell line, doses of 3.125, 6.25, 12.5, 25, 100, 200, 400 and 800 µg/mL in 1% (v/v) DMSO of all samples were tested. Ethyl acetate and chloroform fractions of Stachys laxa against proliferation of T47D and HT-29 cell lines and chloroform fraction of Stachys subaphylla and Stachys subaphylla ethyl acetate fraction toward T47D cell line exhibited highest cytotoxic activity (IC50 < 50 µg/mL). Ethyl acetate and chloroform fractions of Stachys turcomanica against HT-29 cell line, except methanol fraction of Stachys subaphylla, the other extrcts on T47D cell line, represented moderate cytotoxic activity (IC50 < 70 µg/mL). All fractions of S. trinervis demonstrated no effective cytotoxic activity. IC50 values confirmed that the growth and proliferation of HT-29 and T47D cells were most affected by chloroform and ethyl acetate fractions of Stachys laxa and Stachys turcomanica due to their nonpolar compounds. PMID:24250483

  11. No Effect of Host Species on Phenoloxidase Activity in a Mycophagous Beetle.

    Directory of Open Access Journals (Sweden)

    Vincent Formica

    Full Text Available Ecological immunology is an interdisciplinary field that helps elucidate interactions between the environment and immune response. The host species individuals experience have profound effects on immune response in many species of insects. However, this conclusion comes from studies of herbivorous insects even though species of mycophagous insects also inhabit many different host species. The goal of this study was to determine if fungal host species as well as individual, sex, body size, and host patch predict one aspect of immune function, phenoloxidase activity (PO. We sampled a metapopulation of Bolitotherus cornutus, a mycophagous beetle in southwestern Virginia. B. cornutus live on three species of fungus that differ in nutritional quality, social environment, and density. A filter paper phenoloxidase assay was used to quantify phenoloxidase activity. Overall, PO activity was significantly repeatable among individuals (0.57 in adult B. cornutus. While there was significant variance among individuals in PO activity, there were surprisingly no significant differences in PO activity among subpopulations, beetles living on different host species, or between the sexes; there was also no effect of body size. Our results suggest that other factors such as age, genotype, disease prevalence, or natal environment may be generating variance among individuals in PO activity.

  12. Tree species diversity effects on soil microbial biomass, diversity and activity across European forest types

    OpenAIRE

    Carnol, Monique; Baeten, Lander; Bosman, Bernard; De Wandeler, Hans; Muys, Bart

    2014-01-01

    Increasing tree species diversity in forests might contribute to ecosystem-service maintenance, as well as to the reconciliation of regulating, provisioning and supporting services within the frame of multifunctional and sustainable forestry. Individual tree species influence biogeochemical cycling through element deposition (throughfall, litterfall), and through microbial activities in the soil. Yet, the influence of mixing tree species on these ecosystem processes is unclear, in particular ...

  13. AMYLOLYTIC ACTIVITIES OF FUNGI SPECIES ON THE SCREENING MEDIUM ADJUSTED TO DIFFERENT pH

    OpenAIRE

    Balkan, Bilal; Aydoğdu, Halide; BALKAN, Seda; ERTAN, Figen

    2014-01-01

    The purpose of this study was to determine the amylolytic activities in different fungal species on the medium with different pH values. In the study, thirty-eight fungal species were screened by using a plate culture method on Czapek-Dox Agar medium with different pH values for the determination of amylase production. Among the tested fungal species; four species on medium adjusted to pH 4.0, ten species on medium with pH 4.5, nine species on medium with pH 5.0, four species on medium with p...

  14. Wetland-based passive treatment systems for gold ore processing effluents containing residual cyanide, metals and nitrogen species.

    Science.gov (United States)

    Alvarez, R; Ordóñez, A; Loredo, J; Younger, P L

    2013-10-01

    Gold extraction operations generate a variety of wastes requiring responsible disposal in compliance with current environmental regulations. During recent decades, increased emphasis has been placed on effluent control and treatment, in order to avoid the threat to the environment posed by toxic constituents. In many modern gold mining and ore processing operations, cyanide species are of most immediate concern. Given that natural degradation processes are known to reduce the toxicity of cyanide over time, trials have been made at laboratory and field scales into the feasibility of using wetland-based passive systems as low-cost and environmentally friendly methods for long-term treatment of leachates from closed gold mine tailing disposal facilities. Laboratory experiments on discrete aerobic and anaerobic treatment units supported the development of design parameters for the construction of a field-scale passive system at a gold mine site in northern Spain. An in situ pilot-scale wetland treatment system was designed, constructed and monitored over a nine-month period. Overall, the results suggest that compost-based constructed wetlands are capable of detoxifying cyanidation effluents, removing about 21.6% of dissolved cyanide and 98% of Cu, as well as nitrite and nitrate. Wetland-based passive systems can therefore be considered as a viable technology for removal of residual concentrations of cyanide from leachates emanating from closed gold mine tailing disposal facilities. PMID:24089077

  15. Antimicrobial activity of methanol extracts of four Parmeliaceae lichen species

    Directory of Open Access Journals (Sweden)

    Stojanović Igor

    2013-01-01

    Full Text Available Antimicrobial activity of methanol extracts of four Parmeliaceae lichens (Hypogymnia physodes (L. Nyl., Evernia prunastri (L. Ach., Flavoparmelia caperata (L. Hale and Parmelia sulcata Taylor against a panel of microbial strains (11 Gram-positive (Enterococus sp., Bacillus subtilllis, Sarcina lutea, Micrococus luteus, Staphylococcus aureus, Clostridium sporogenes and Gram-negative bacteria (Escherichia coli, Proteus vulgaris, Salmonela enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, the filamentous fungus A. niger and the yeast C. albicans was assayed using a disk diffusion method (1 mg of the extract per disc; extracts were dissolved in methanol, 25 mg/mL. All tested extracts showed moderate antimicrobial activity. Multivariate statistical treatment (agglomerative hierarchical clustering analysis, AHC of the obtained results allowed grouping of the samples according to their antimicrobial potential against different strains: antimicrobial profile of H. physodes and E. prunastri extracts were comparable; the similar is true for F. caperata and P. sulcata samples. In addition, based on the similarities/ dissimilarities in their susceptibility toward the tested extracts, two groups of microorganisms could be distinguished: Group I - P. vulgaris, K. pneumoniae (Gram-negative bacteria, A. niger and C. albicans; Group II - E. coli, S. enteritidis, P. aeruginosa (Gram-negative bacteria and all of the assayed Gram-positive strains. [Projekat Ministarstva nauke Republike Srbije, br. 172044

  16. Diuretic and natriuretic activity of two mistletoe species in rats

    Directory of Open Access Journals (Sweden)

    Namita Jadhav

    2010-01-01

    Full Text Available In different cultural groups, the hemiparasitic plants of the families Loranthaceae and Viscaceae (mistletoes are frequently used in the treatment of hypertension and/or as diuretic agents. However, it remains unclear as to what commonality makes them diuretic agents or a remedy for hypertension. In this article, the diuretic activity of methanol extracts of Viscum articulatum (VA Burm. f. and Helicanthus elastica (HE (Ders. Dans. in rats is reported. The extracts were administered orally at doses of 100, 200 and 400 mg/kg to rats that had been fasted and deprived of water for 18 hours. Investigations were carried out for diuretic, saluretic and natriuretic effects. The polyphenolic and triterpenoid contents were determined quantitatively using chemical assays and high performance liquid chromatography (HPLC analysis, respectively. The extracts of VA and HE demonstrated significant and dose-dependent diuretic activity in rats. It was found that while VA mimics the furosemide pattern, HE demonstrated a dose-dependent increase in diuresis, along with an increase in potassium-sparing effects. Phytochemical analysis revealed that polyphenolics and triterpenoids, such as oleanolic acid and lupeol, are the major phytochemicals involved. It was also found that in different combinations, these phytochemicals differed in the way they influenced the electrolyte excretion. A higher content of polyphenolics in association with lower triterpenoid content was found to favor potassium-sparing effects.

  17. Visible-light-activated photocatalysis of malodorous dimethyl disulphide using nitrogen-enhanced TiO2.

    Science.gov (United States)

    Jo, W K; Shin, M H

    2010-04-14

    This study evaluated the feasibility of applying a visible-light-activated photocatalytic technique to cleanse air dimethyl disulphide (DMDS) at low concentration conditions (0.027-5.4 ppm), by using nitrogen-enhanced TiO2. In addition, the applicability of a backup adsorption unit for the secondary control of DMDS exiting from the photocatalytic oxidation (PCO) unit was investigated. The PCO unit functioned effectively for the control of DMDS at low concentration levels ( pollution level (0.027-5.4 ppm), as well as DMDS exiting from the PCO units.

  18. Antiparasitic activity of prenylated benzoic acid derivatives from Piper species.

    Science.gov (United States)

    Flores, Ninoska; Jiménez, Ignacio A; Giménez, Alberto; Ruiz, Grace; Gutiérrez, David; Bourdy, Genevieve; Bazzocchi, Isabel L

    2009-03-01

    Fractionation of dichloromethane extracts from the leaves of Piper heterophyllum and P. aduncum afforded three prenylated hydroxybenzoic acids, 3-[(2E,6E,10E)-11-carboxy-3,7,15-trimethyl-2,6,10,14-hexadecatetraenyl)-4,5-dihydroxybenzoic acid, 3-[(2E,6E,10E)-11-carboxy-13-hydroxy-3,7,15-trimethyl-2,6,10,14-hexadecatetraenyl]-4,5-dihydroxybenzoic acid and 3-[(2E,6E,10E)-11-carboxy-14-hydroxy-3,7,15-trimethyl-2,6,10,15-hexadecatetraenyl]-4,5-dihydroxybenzoic acid, along with the known compounds, 4,5-dihydroxy-3-(E,E,E-11-formyl-3,7,15-trimethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid (arieianal), 3,4-dihydroxy-5-(E,E,E-3,7,11,15-tetramethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid, 4-hydroxy-3-(E,E,E-3,7,11,15-tetramethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid, 3-(3,7-dimethyl-2,6-octadienyl)-4-methoxy-benzoic acid, 4-hydroxy-3-(3,7-dimethyl-2,6-octadienyl)benzoic acid and 4-hydroxy-3-(3-methyl-1-oxo-2-butenyl)-5-(3-methyl-2-butenyl)benzoic acid. Their structures were elucidated on the basis of spectroscopic data, including homo- and heteronuclear correlation NMR experiments (COSY, HSQC and HMBC) and comparison with data reported in the literature. Riguera ester reactions and optical rotation measurements established the compounds as racemates. The antiparasitic activity of the compounds were tested against three strains of Leishmania spp., Trypanosoma cruzi and Plasmodium falciparum. The results showed that 3-(3,7-dimethyl-2,6-octadienyl)-4-methoxy-benzoic acid exhibited potent and selective activity against L. braziliensis (IC(50) 6.5 microg/ml), higher that pentamidine used as control. Moreover, 3-[(2E,6E,10E)-11-carboxy-3,7,15-trimethyl- 2,6,10,14-hexadecatetraenyl)-4,5-dihydroxybenzoic acid and 4-hydroxy-3-(3-methyl-1-oxo-2-butenyl)-5-(3-methyl-2-butenyl)benzoic acid showed moderate antiplasmodial (IC(50) 3.2 microg/ml) and trypanocidal (16.5 microg/ml) activities, respectively. PMID:19361822

  19. Purification and in vitro activities of the native nitrogen fixation control proteins NifA and NifL.

    Science.gov (United States)

    Austin, S; Buck, M; Cannon, W; Eydmann, T; Dixon, R

    1994-06-01

    The prokaryotic enhancer-binding protein NifA stimulates transcription at a distance by binding to sequences upstream of nitrogen fixation (nif) promoters and catalyzing the formation of open promoter complexes by RNA polymerase containing the alternative sigma factor, sigma 54. The activity of NifA in vivo is modulated by the negative regulatory protein NifL in response to environmental oxygen and fixed nitrogen. To date, a detailed biochemical analysis of these proteins from the model diazotroph Klebsiella pneumoniae has been hindered by their insolubility. We have now purified NifA and NifL from Azotobacter vinelandii in their native form. NifA is competent in specific DNA binding, transcriptional activation, and response to negative regulation by NifL in vitro. In contrast to the conserved mechanism of phosphotransfer demonstrated by other two-component regulatory systems, our results support a model in which NifL regulates the activity of NifA via a protein-protein steric block interaction rather than a catalytic modification of NifA. PMID:8206822

  20. Enhancement of phenolics, resveratrol and antioxidant activity by nitrogen enrichment in cell suspension culture of Vitis vinifera.

    Science.gov (United States)

    Sae-Lee, Napaporn; Kerdchoechuen, Orapin; Laohakunjit, Natta

    2014-01-01

    Ammonium nitrate (NH4NO3), an important nitrogen source (34% N), has been used as an elicitor to stimulate plant growth and development as well as induce secondary metabolites under controlled conditions. In the present paper, we investigated the enhancement of cell biomass, total phenolics, resveratrol levels, and antioxidant activity of Vitis vinifera cv. Pok Dum by nitrogen enrichment (MS medium supplemented with NH4NO3 at 0, 500, 1,000, 5,000 and 10,000 mg/L). The highest accumulations of biomass, phenolics and resveratrol contents were observed at 8.8-fold (86.6 g DW/L), 15.9-fold (71.91 mg GAE/g DW) and 5.6-fold (277.89 µg/g DW) by the 14th day, in the medium supplemented with 500 mg/L NH4NO3. Moreover, the antioxidant activities of cultured grape cells estimated by the DPPH· and ABTS·+ assay were positively correlated with phenolics and resveratrol, and the maximum activity was also observed in cultured cells with 500 mg/L NH4NO3 at 176.11 and 267.79 mmol TE/100 g DW, respectively. PMID:24962393

  1. Enhancement of Phenolics, Resveratrol and Antioxidant Activity by Nitrogen Enrichment in Cell Suspension Culture of Vitis vinifera

    Directory of Open Access Journals (Sweden)

    Napaporn Sae-Lee

    2014-06-01

    Full Text Available Ammonium nitrate (NH4NO3, an important nitrogen source (34% N, has been used as an elicitor to stimulate plant growth and development as well as induce secondary metabolites under controlled conditions. In the present paper, we investigated the enhancement of cell biomass, total phenolics, resveratrol levels, and antioxidant activity of Vitis vinifera cv. Pok Dum by nitrogen enrichment (MS medium supplemented with NH4NO3 at 0, 500, 1,000, 5,000 and 10,000 mg/L. The highest accumulations of biomass, phenolics and resveratrol contents were observed at 8.8-fold (86.6 g DW/L, 15.9-fold (71.91 mg GAE/g DW and 5.6-fold (277.89 µg/g DW by the 14th day, in the medium supplemented with 500 mg/L NH4NO3. Moreover, the antioxidant activities of cultured grape cells estimated by the DPPH· and ABTS·+ assay were positively correlated with phenolics and resveratrol, and the maximum activity was also observed in cultured cells with 500 mg/L NH4NO3 at 176.11 and 267.79 mmol TE/100 g DW, respectively.

  2. Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit

    OpenAIRE

    Hoefman, Sven; van der Ha, David; Boon, Nico; Vandamme, Peter; de Vos, Paul; Heylen, Kim

    2014-01-01

    Background: The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed...

  3. Anti-Candida activity of Quercus infectoria gall extracts against Candida species

    OpenAIRE

    Nur Saeida Baharuddin; Hasmah Abdullah; Wan Nor Amilah Wan Abdul Wahab

    2015-01-01

    Background: Galls of Quercus infectoria have been traditionally used to treat common ailments, including yeast infections caused by Candida species. Objective: This study aimed to evaluate the in vitro anti-Candida activity of Q. infectoria gall extracts against selected Candida species. Materials and Methods: Methanol and aqueous extracts of Q. infectoria galls were tested for anti-Candida activity against Candida albicans, Candida krusei, Candida glabrata, Candida parapsilosis and Candida t...

  4. Screening of radical scavenging activity and polyphenol content of Bulgarian plant species

    OpenAIRE

    Milena Nikolova

    2011-01-01

    Background: Discovery of new plant species with antioxidant properties is a priority of many research teams. Most of the species included in this study are unstudied for antioxidant properties, but they are taxonomically related to reference plants with well-documented antioxidant activity. Materials and Methods: Free radical scavenging activity of plant extracts was evaluated using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. An aluminum chloride colorimetric method was used for flavonoid d...

  5. Isotopic and enzymatic analyses of planktonic nitrogen utilisation in the vicinity of Cape Sines (Portugal) during weak upwelling activity

    Science.gov (United States)

    Slawyk, Gerd; Coste, Bernard; Collos, Yves; Rodier, Martine

    1997-01-01

    Using measurements of 15N uptake and activities of nitrate reductase and glutamine synthetase, the utilization of nitrogenous nutrients by microplankton in the Portuguese upwelling area was investigated. During this cruise the euphotic zone of coastal waters was in most cases bisected by a nitracline forming two layers. Total inorganic nitrogen uptake rates (NH 4+ + NO 3-) in the upper mixed and nitrate-impoverished layer ranged from 0.1 to 0.8 nM h -1 and were primarily supported by regenerated (ammonium) nitrogen (62-97%), whereas they varied between 0.9 and 10.4 nM h -1 in the deep nitrate-rich layer and were mainly driven by new (nitrate) nitrogen (52-82%). Depth profiles of Chl a-specific uptake rates for ammonium and nitrate paralleled those of absolute uptake rates, i.e. values of VNH 4+Chl were highest (up to 16.1 nmol μg -1 h -1) in nitrate-poor surface waters while values of VNO 3-Chl were maximum (up to 8.4 nmol μg -1 h -1)within the nitracline. This latter vertical ordering of planktonic nitrogen nutrition was consistent with an aged upwelling situation. However, applying several indices of cell metabolism and nutritional status, such as 15N uptake/enzyme activity, surge uptake internally controlled uptake, and V maxChl/K t ratios, we were able to demonstrate that the phytoplankton assemblages inhabiting the nutrient-impoverished upper layer still bore the signature of physically mediated nitrogen (nitrate) supply generated by active upwelling that had occurred during the week before our visit to the area. This signature was the most evident in samples from the station furthest inshore and faded with distance from shore as a result of the deepening of the nitrate isopleths (weakening of upwelling activity), which showed the same offshore trend. The appearance of nitrate-rich waters at the surface, after a strong pulse of upwelling favourable winds just before the end of the cruise, led to a five-fold increase in average (over the euphotic zone

  6. Spatial and decadal variations in inorganic nitrogen wet deposition in China induced by human activity

    OpenAIRE

    Jia, Yanlong; Yu, Guirui; He, Nianpeng; Zhan, Xiaoyun; Fang, Huajun; Sheng, Wenping; Zuo, Yao; Zhang, Dayong; Wang, Qiufeng

    2014-01-01

    Atmospheric nitrogen (N) deposition, an important component in the global N cycle, has increased sharply in recent decades in China. Here, we constructed national-scale inorganic N wet deposition (Ndep) patterns in China based on data from 280 observational sites and analysed the effects of anthropogenic sources and precipitation on Ndep. Our results showed that the mean Ndep over China increased approximately 25%, from 11.11 kg ha−1 a−1 in the 1990s to 13.87 in the 2000s. Ndep was highest ov...

  7. Benzoic acid derivatives from Piper species and their antiparasitic activity.

    Science.gov (United States)

    Flores, Ninoska; Jiménez, Ignacio A; Giménez, Alberto; Ruiz, Grace; Gutiérrez, David; Bourdy, Genevieve; Bazzocchi, Isabel L

    2008-09-01

    Piper glabratum and P. acutifolium were analyzed for their content of main secondary constituents, affording nine new benzoic acid derivatives (1, 2, 4, 5, 7, and 10-13), in addition to four known compounds (3, 6, 8, and 9). Their structures were elucidated on the basis of spectroscopic data. Riguera ester reactions and optical rotation measurements established the new compounds as racemates. In the search for antiparasitic agents, the compounds were evaluated in vitro against the promastigote forms of Leishmania spp., Trypanosoma cruzi, and Plasmodium falciparum. Among the evaluated compounds, methyl 3,4-dihydroxy-5-(3'-methyl-2'-butenyl)benzoate (7) exhibited leishmanicidal effect (IC50 13.8-18.5 microg/mL) against the three Leishmania strains used, and methyl 3,4-dihydroxy-5-(2-hydroxy-3-methylbutenyl)benzoate (1), methyl 4-hydroxy-3-(2-hydroxy-3-methyl-3-butenyl)benzoate (3), and methyl 3,4-dihydroxy-5-(3-methyl-2-butenyl) benzoate (7) showed significant trypanocidal activity, with IC50 values of 16.4, 15.6, and 18.5 microg/mL, respectively. PMID:18712933

  8. Active sensing: An innovative tool for evaluating grain yield and nitrogen use efficiency of multiple wheat genotypes

    Science.gov (United States)

    Naser, Mohammed Abdulridha

    Precision agricultural practices have significantly contributed to the improvement of crop productivity and profitability. Remote sensing based indices, such as Normalized Difference Vegetative Index (NDVI) have been used to obtain crop information. It is used to monitor crop development and to provide rapid and nondestructive estimates of plant biomass, nitrogen (N) content and grain yield. Remote sensing tools are helping improve nitrogen use efficiency (NUE) through nitrogen management and could also be useful for high NUE genotype selection. The objectives of this study were: (i) to determine if active sensor based NDVI readings can differentiate wheat genotypes, (ii) to determine if NDVI readings can be used to classify wheat genotypes into grain yield productivity classes, (iii) to identify and quantify the main sources of variation in NUE across wheat genotypes, and (iv) to determine if normalized difference vegetation index (NDVI) could characterize variability in NUE across wheat genotypes. This study was conducted in north eastern Colorado for two years, 2010 and 2011. The NDVI readings were taken weekly during the winter wheat growing season from March to late June, in 2010 and 2011 and NUE were calculated as partial factor productivity and as partial nitrogen balance at the end of the season. For objectives i and ii, the correlation between NDVI and grain yield was determined using Pearson's product-moment correlation coefficient (r) and linear regression analysis was used to explain the relationship between NDVI and grain yield. The K-means clustering algorithm was used to classify mean NDVI and mean grain yield into three classes. For objectives iii and iv, the parameters related to NUE were also calculated to measure their relative importance in genotypic variation of NUE and power regression analysis between NDVI and NUE was used to characterize the relationship between NDVI and NUE. The results indicate more consistent association between grain

  9. Recovery of cholinesterase activity in five avian species exposed to dicrotophos, an organophosphorus pesticide

    Science.gov (United States)

    Fleming, W.J.; Grue, C.E.

    1981-01-01

    The responses of brain and plasma cholinesterase (ChE) activities were examined in mallard ducks, bobwhite quail, barn owls, starlings, and common grackles given oral doses of dicrotophos, an organophosphorus insecticide. Up to an eightfold difference in response of brain ChE activity to dicrotophos was found among these species. Brain ChE activity recovered to within 2 SD of normal within 26 days after being depressed 55 to 64%. Recovery of brain ChE activity was similar among species and followed the model Y = a + b (log10X).

  10. Antioxidant Activities and Phytochemical Study of Leaf Extracts from 18 Indigenous Tree Species in Taiwan

    OpenAIRE

    Ho, Shang-Tse; Tung, Yu-Tang; Chen, Yong-Long; Zhao, Ying-Ying; Chung, Min-Jay; Wu, Jyh-Horng

    2012-01-01

    The objective of this study is to assess antioxidant activities of methanolic extracts from the leaves of 18 indigenous tree species in Taiwan. Results revealed that, among 18 species, Acer oliverianum exhibited the best free radical scavenging activities. The IC50 values were 5.8 and 11.8 μg/mL on DPPH radical and superoxide radical scavenging activities, respectively. In addition, A. oliverianum also exhibited the strongest ferrous ion chelating activity. Based on a bioactivity-guided isola...

  11. Ecological Impact on Nitrogen and Phosphorus Cycling of a Widespread Fast-growing Leguminous Tropical Forest Plantation Tree Species, Acacia mangium

    Directory of Open Access Journals (Sweden)

    Shigehiro Ishizuka

    2011-11-01

    Full Text Available Symbiotic nitrogen fixation is one of the major pathways of N input to forest ecosystems, enriching N availability, particularly in lowland tropics. Recently there is growing concern regarding the wide areas of fast-growing leguminous plantations that could alter global N2O emissions. Here, we highlight substantially different N and phosphorus utilization and cycling at a plantation of Acacia mangium, which is N2-fixing and one of the major plantation species in tropical/subtropical Asia. The litterfall, fresh leaf quality and fine-root ingrowth of A. mangium were compared to those of non-N2-fixing Swietenia macrophylla and coniferous Araucaria cunninghamii in wet tropical climates in Borneo, Malaysia. The N and P concentrations of the A. mangium fresh leaves were higher than those of the other two species, whereas the P concentration in the leaf-litterfall of A. mangium was less than half that of the others; in contrast the N concentration was higher. The N:P ratio in the A. mangium leaf was markedly increased from fresh-leaf (29 to leaf-litterfall (81. Although the N flux in the total litterfall at the A. mangium plantation was large, the fine-root ingrowth of A. mangium significantly increased by applying both N and P. In conclusion, large quantities of N were accumulated and returned to the forest floor in A. mangium plantation, while its P resorption capacity was efficient. Such large N cycling and restricted P cycling in wide areas of monoculture A. mangium plantations may alter N and P cycling and their balance in the organic layer and soil on a stand level.

  12. Studies on Glutamine Synthetase Activity in Sugar Beet(Beta vulgaris L.) under Different Levels of Nitrogen

    Institute of Scientific and Technical Information of China (English)

    YanGuiping; YanHui; 等

    1995-01-01

    It was shown from the experiment that glutamine synthetase activity (GSA) in both leaf blades and roots under different nitrogen levels rose rapidly to reach its peak from seeding stage to foliage rapid growth stage and declined to its lowest level at the latter stage of root rapid growth,and then increased slightly,GSA in leaf blades had positive correlation with nitrogen level during the whole period of growth,GSA in roots showed the same tendency as it in leaf blades at the early middle stage of growth,but at the latter stage of growth,no positive correlation was established.GSA in leaf blades was the strongest compared with crowns,petioles and roots,and could represent the highest enzyme activity of the whole pant,GSA had quadratic curvilinear correlation with root yield and sugar production.GSA in leaf blades had significant positive correlation with α-NH2-N at the foliage rapid growth stage.

  13. Synthesis and Characterization of Thiophene-derived Amido Bis-nitrogen Mustard and Its Antimicrobial and Anticancer Activities

    Institute of Scientific and Technical Information of China (English)

    唐一丹; 张景勍; 张少林; 耿蓉霞; 周成合

    2012-01-01

    The thiophene-derived amido bis-nitrogen mustard N2,N2,N5,N5-tetrakis(2-chloroethyl)-3,4-dimethylthio- phene-2,5-dicarboxamide was designed and synthesized via five-step reactions from commercially available 2-chloroacetonitrile. This target compound was confirmed by 1H NMR, 13C NMR, MS, IR spectra and elemental analyses, and its structure was further characterized by X-ray single-crystal analysis. The biological activities for the title compound and some intermediates were evaluated in vitro for their antibacterial, antifungal and cytotoxic activities. The preliminary results showed that the title compound could inhibit efficiently the growth of the tested microorganisms including drug-resistant bacteria MRSA to some extent. Moreover, the target compound was found to be effective against prostatic carcinoma cell line (PC-3), breast carcinoma cell line (MCF-7), colon carcinoma (LoVo) and lung cancer (A549). Especially, it gave selective antitumor efficacy against prostatic carcinoma cell line (PC-3) at a low dose. Keywords nitrogen mustard, thiophene, antibacterial, antifungal, cytotoxicity

  14. Involvement of Nitrogen on Flavonoids, Glutathione, Anthocyanin, Ascorbic Acid and Antioxidant Activities of Malaysian Medicinal Plant Labisia pumila Blume (Kacip Fatimah)

    OpenAIRE

    Zaharah Abdul Rahman; Jaafar, Hawa Z. E.; Mohd Hafiz Ibrahim; Asmah Rahmat

    2011-01-01

    A split plot 3 by 4 experiment was designed to characterize the relationship between production of gluthatione (GSH), oxidized gluthatione (GSSG), total flavonoid, anthocyanin, ascorbic acid and antioxidant activities (FRAP and DPPH) in three varieties of Labisia pumila Blume, namely the varieties alata, pumila and lanceolata, under four levels of nitrogen fertilization (0, 90, 180 and 270 kg N/ha) for 15 weeks. The treatment effects were solely contributed by nitrogen application; there was ...

  15. C-H bond activation by metal-superoxo species: what drives high reactivity?

    Science.gov (United States)

    Ansari, Azaj; Jayapal, Prabha; Rajaraman, Gopalan

    2015-01-01

    Metal-superoxo species are ubiquitous in metalloenzymes and bioinorganic chemistry and are known for their high reactivity and their ability to activate inert C-H bonds. The comparative oxidative abilities of M-O2(.-) species (M = Cr(III), Mn(III), Fe(III), and Cu(II)) towards C-H bond activation reaction are presented. These superoxo species generated by oxygen activation are found to be aggressive oxidants compared to their high-valent metal-oxo counterparts generated by O⋅⋅⋅O bond cleavage. Our calculations illustrate the superior oxidative abilities of Fe(III)- and Mn(III)-superoxo species compared to the others and suggest that the reactivity may be correlated to the magnetic exchange parameter.

  16. Antioxidant activity and phenolic content of leaf infusions of Myrtaceae species from Cerrado (Brazilian Savanna).

    Science.gov (United States)

    Takao, L K; Imatomi, M; Gualtieri, S C J

    2015-11-01

    There is considerable interest in identifying new antioxidants from plant materials. Several studies have emphasized the antioxidant activity of species belonging to the Myrtaceae family. However, there are few reports on these species from the Cerrado (Brazilian savanna). In this study, the antioxidant activity and phenolic content of 12 native Myrtaceae species from the Cerrado were evaluated (Blepharocalyx salicifolius, Eugenia bimarginata, Eugenia dysenterica, Eugenia klotzschiana, Hexachlamys edulis, Myrcia bella, Myrcia lingua, Myrcia splendens, Myrcia tomentosa, Psidium australe, Psidium cinereum, and Psidium laruotteanum). Antioxidant potential was assessed using the antioxidant activity index (AAI) by the DPPH method and total phenolic content (TPC) by the Folin-Ciocalteu assay. There was a high correlation between TPC and AAI values. Psidium laruotteanum showed the highest TPC (576.56 mg GAE/g extract) and was the most potent antioxidant (AAI = 7.97, IC50 = 3.86 µg·mL-1), with activity close to that of pure quercetin (IC50 = 2.99 µg·mL-1). The extracts of nine species showed IC50 of 6.24-8.75 µg·mL-1. Most species showed TPC and AAI values similar to or higher than those for Camellia sinensis, a commonly consumed tea with strong antioxidant properties. The results reveal that the analyzed Myrtaceae species from the Cerrado possess high phenolic contents and antioxidant activities. Thus, they are a potential source of new natural antioxidants.

  17. Digestive enzyme activity of two stonefly species (Insecta, Plecoptera) and their feeding habits.

    Science.gov (United States)

    de Figueroa, J M Tierno; Trenzado, C E; López-Rodríguez, M J; Sanz, A

    2011-11-01

    The digestive enzymes of two stoneflies species, Hemimelaena flaviventris and Isoperla morenica, were studied for the first time. These species are temporary water inhabitants and exhibit great feeding plasticity. Although they are traditionally referred to as predators, a previous study revealed that H. flaviventris incorporates some diatoms into its diet in addition to feeding usually on several prey, and I. morenica (in that study under the name of I. curtata) only feeds on animals occasionally. The enzymatic activities of digestive amylase, lipase, protease, trypsin and chymotrypsin were determined for each species at the same developmental stage. The results show that H. flaviventris has a greater digestive enzymatic pool and higher relative and absolute protease, lipase and trypsin activities than I. morenica. The latter has a relative higher amylase activity. As higher amylase activity is typical of phytophagous species and higher protease activity typical of carnivorous species; these results reveal that H. flaviventris is a more efficient zoophagous species than I. morenica. The ecological implications of these findings, including the higher secondary production of H. flaviventris in its habitat, are discussed.

  18. The effect of water stress on nitrate reductase activity and nitrogen and phosphorus contents in cuminum cyminum l

    International Nuclear Information System (INIS)

    Cumin (Cuminum cyminum L.) is a plant with great medicinal importance cultivated in many regions such as Iran, India, Indonesia, Afghanistan, Pakistan, Lebanon, Syria and Turkey. In this research, nitrogen and phosphorus concentrations and nitrate reductase enzyme activity were studied in cumin under flooding stress. Cumin plants were cultivated in pots containing garden soil (in 1 cm depth, 15 -20 degree C, 14 h light and 10 h darkness). Germination took place after 2 weeks. Flooding stress was applied 6 weeks after germination on a number of pots according to their field capacity (FC) (2, 3, and 4 fold) for 1 week; a number of pots were also considered as controls with field capacity. Plants were then harvested and chemical analysis of the factors under study was done using roots and shoots of the plants exposed to flooding conditions and the control plants. The experiment had a completely randomized design in which four levels of water in the soil (2FC, 3FC, 4FC) were compared. Analysis of variance was carried out using SPSS software and means were compared by Duncan's test at [ greater or equal to = 0.05 significance level. The results showed that in comparison with control plants, nitrogen and phosphorus concentrations were significantly lower in both shoots and roots of flooded plants. This decrease was more pronounced in treated plants exposed to 4 X field capacity conditions. Nitrogen concentration in roots and shoots of treated plants showed a significant decrease in comparison with control plants and this was more noticeable in treated plants exposed to 4 X field capacity conditions. Moreover, concentration of nitrite produced from nitrate reduction catalyzed by nitrate reductase enzyme in roots and shoots of treated plants had a significant increase in comparison with control plants. Treated plants exposed to 4 X field capacity conditions showed the most increase. Also the study showed that cumin seeds could survive in flooding environment for 14 days

  19. High Temperature at Grain-filling Stage Affects Nitrogen Metabolism Enzyme Activities in Grains and Grain Nutritional Quality in Rice

    Institute of Scientific and Technical Information of China (English)

    LIANG Cheng-gang; CHEN Li-ping; WANG Yan; LIU Jia; Xu Guang-li; LI Tian

    2011-01-01

    Rice plants would more frequently suffer from high temperature (HT) stress at the grain-filling stage in future.A japonica rice variety Koshihikari and an indica rice variety IR72 were used to study the effect of high temperature on dynamic changes of glutamine synthetase (GS) activity,glutamate synthase (GOGAT) activity,glutamic oxalo-acetic transminase (GOT) activity,glutamate pyruvate transminase (GPT) activity in grains and grain nutritional quality at the grain-filling stage.Under HT,the activities of GOGAT,GOT,GPT and soluble protein content in grains significantly increased,whereas GS activity significantly decreased at the grain-filling stage.In addition to the increase of protein and amino acids contents,it was suggested that GOGAT,GOT and GPT in grains played important roles in nitrogen metabolism at the grain-filling stage.Since the decrease of GS activity in grains did not influence the accumulations of amino acids and protein,it is implied that GS might not be the key enzyme in regulating glutamine content in grains.

  20. Nutrition Intensity in Ternary Diagrams Interpretation for Some Ornamental Species Cultivated on Organic Substrate with Increased Biological Activity

    Directory of Open Access Journals (Sweden)

    Roxana Maria MADJAR

    2014-12-01

    Full Text Available Nowadays, many biodegradable organic wastes no longer need to represent an environmental hazard and as a consequence, they could be recycled to obtain horticultural substrates. An experiment was conducted on two deciduous (Tamarix tetrandra, Ligustrum ovalifolium ‘Aureum’ and two coniferous species (Chamaecyparis pisifera ‘Boulevard’, Chamaecyparis lawsoniana ‘Stardust’ grown on a soil mixture of forestry compost, leaves compost, peat and grape marc compost. The aim of the research was to investigate the response to fertilization and to obtain valuable information regarding absorption rate of nutritive elements during vegetation. Nitrogen data show a lowering of its nutritive equilibrium point towards autumn in the leaves of deciduous shrubs species. Resorption of nutrients before leaves fall occurs due to conservation process in woody plants with deciduous leaves. In the case of coniferous species the lowering of nitrogen content is less intense. The monthly fertilization with Coïc solution indicates no influence on nitrogen metabolism of this species. The exception was on Ligustrum with differences between nitrogen content in fertilized and unfertilized plants. The phosphorus nutritive equilibrium point reveals a decrease during the summer months (July - August, the species presenting the lowest values in this period and the cause of this behaviour was the plants adaptation to high temperature and low humidity. Potassium nutritive equilibrium data indicates small differences in the unfertilized plants in comparison with those fertilized in all species. The novelty of the research is represented by the ternary diagrams N-P-K that were constructed, interpreted and reported for dendrologic species.

  1. Synthesis and study on biological activity of nitrogen-containing heterocyclic compounds – regulators of enzymes of nucleic acid biosynthesis

    Directory of Open Access Journals (Sweden)

    Alexeeva I. V.

    2013-07-01

    Full Text Available Results of investigations on the development of new regulators of functional activity of nucleic acid biosynthesis enzymes based on polycyclic nitrogen-containing heterosystems are summarized. Computer design and molecular docking in the catalytic site of target enzyme (T7pol allowed to perform the directed optimization of basic structures. Several series of compounds were obtained and efficient inhibitors of herpes family (simple herpes virus type 2, Epstein-Barr virus, influenza A and hepatitis C viruses were identified, as well as compounds with potent antitumor, antibacterial and antifungal activity. It was established that the use of model test systems based on enzymes participating in nucleic acids synthesis is a promising approach to the primary screening of potential inhibitors in vitro.

  2. Amino substituted nitrogen heterocycle ureas as kinase insert domain containing receptor (KDR inhibitors: Performance of structure–activity relationship approaches

    Directory of Open Access Journals (Sweden)

    Hayriye Yilmaz

    2015-06-01

    Full Text Available A quantitative structure–activity relationship (QSAR study was performed on a set of amino-substituted nitrogen heterocyclic urea derivatives. Two novel approaches were applied: (1 the simplified molecular input-line entry systems (SMILES based optimal descriptors approach; and (2 the fragment-based simplex representation of molecular structure (SiRMS approach. Comparison with the classic scheme of building up the model and balance of correlation (BC for optimal descriptors approach shows that the BC scheme provides more robust predictions than the classic scheme for the considered pIC50 of the heterocyclic urea derivatives. Comparison of the SMILES-based optimal descriptors and SiRMS approaches has confirmed good performance of both techniques in prediction of kinase insert domain containing receptor (KDR inhibitory activity, expressed as a logarithm of inhibitory concentration (pIC50 of studied compounds.

  3. Salinity and Salicylic Acid Interactions in Affecting Nitrogen Assimilation, Enzyme Activity, Ions Content and Translocation Rate of Maize Plants

    International Nuclear Information System (INIS)

    This study was carried out to establish the relationship between nitrogen metabolism, enzyme activity, ions concentration as well as the translocation rate (TR) of carbohydrates and salicylic acid (SA) in salt-stressed maize (Zea mays L). Salicylic acid plus salinity treatment highly significantly increased: nucleic acids (DNA and RNA), protein content, phosphoenolpyruvate carboxylase (PEPCase) and nitrate reductase (NR) and inhibited nucleases (DNase and RNase) activities compared with Na CI-treated plants. In addition, the ionic levels of potassium (K), phosphorus (P), nitrate (NO3) and the translocation rate of the labelled photo assimilates have also been stimulated while sodium (Na) ions content was decreased. It is concluded that, salinazid maize plants might show an enhancement in their growth pattern upon salicylic acid application

  4. Tuning of ZIF-Derived Carbon with High Activity, Nitrogen Functionality, and Yield - A Case for Superior CO2 Capture.

    Science.gov (United States)

    Gadipelli, Srinivas; Guo, Zheng Xiao

    2015-06-22

    A highly effective and facile synthesis route is developed to create and tailor metal-decorated and nitrogen-functionalized active microporous carbon materials from ZIF-8. Clear metal- and pyrrolic-N-induced enhancements of the cyclic CO2 uptake capacities and binding energies are achieved, particularly at a much lower carbonization temperature of 700 °C than those often reported (1000 °C). The high-temperature carbonization can enhance the porosity but only at the expense of considerable losses of sample yield and metal and N functional sites. The findings are comparatively discussed with carbons derived from metal-organic frameworks (MOFs) reported previously. Furthermore, the porosity of the MOF-derived carbon is critically dependent on the structure of the precursor MOF and the crystal growth. The current strategy offers a new and effective route for the creation and tuning of highly active and functionalized carbon structures in high yields and with low energy consumption.

  5. DMPD: NF-kappaB activation by reactive oxygen species: fifteen years later. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16723122 NF-kappaB activation by reactive oxygen species: fifteen years later. Gloi...svg) (.html) (.csml) Show NF-kappaB activation by reactive oxygen species: fifteen years later. PubmedID 167...23122 Title NF-kappaB activation by reactive oxygen species: fifteen years later.

  6. High-temperature thermodynamic activities of zirconium in platinum alloys determined by nitrogen-nitride equilibria

    International Nuclear Information System (INIS)

    A high-temperature nitrogen-nitride equilibrium apparatus is constructed for the study of alloy thermodynamics to 23000C. Zirconium-platinum alloys are studied by means of the reaction 9ZrN + 11Pt → Zr9Pt11 + 9/2 N2. Carful attention is paid to the problems of diffusion-limited reaction and ternary phase formation. The results of this study are and a/sub Zr//sup 19850C/ = 2.4 x 10-4 in Zr9Pt11 ΔG/sub f 19850C/0 Zr9Pt11 less than or equal to -16.6 kcal/g atom. These results are in full accord with the valence bond theory developed by Engel and Brewer; this confirms their prediction of an unusual interaction of these alloys

  7. [Effects of applying different kind fertilizers on enzyme activities related to carbon, nitrogen, and phosphorus cycles in reddish paddy soil].

    Science.gov (United States)

    Xu, Li-Li; Wang, Qiu-Bing; Zhang, Xin-Yu; Sun, Xiao-Min; Dai, Xiao-Qin; Yang, Feng-Ting; Bu, Jin-Feng; Wang, Hui-min

    2013-04-01

    Based on the long-term fixed position experimental data from Qianyanzhou Ecological Experiment Station, Chinese Academy of Sciences in 1998, this paper analyzed the effects of applying different kind fertilizers (straw, ST; pig manure, OM; and chemical fertilizer, NPK) on the nutrients (C, N, and P) status and the activities of related enzymes ( beta-1,4-glucosidase, betaG; beta-1,4-N-acetylglucosaminidase, NAG; L-leucine aminopeptidase, LAP; and acid phosphatase, AP) in reddish paddy soil. With the application of OM, the activities of soil betaG, NAG, and LAP increased significantly, as compared with other treatments, and were 1.4, 2. 6, and 1.9 times higher than the control (CK) , respectively. Applying OM also improved the ratio of soil organic carbon to total nitrogen (C/N), but decreased the soil betaG/(NAG+LAP) ratio, suggesting that pig manure could benefit the degradation of soil cellulose and the accumulation of soil organic carbon. Applying NPK increased the activities of soil betaG, NAG, and LAP, but decreased the AP activity, with a decrement of 34% as compared with CK. Under the application of NPK, the soilbetaG/AP and (NAG+ LAP)/AP ratios increased, but the ratios of soil organic carbon to total phosphorus (C/P) and of soil total nitrogen to total phosphorus (N/P) decreased, indicating that chemical fertilizers could induce the accumulation of soil inorganic phosphorus, and inhibit the microbial functions of degrading polysaccharides and phosphate phospholipids.

  8. Diversity of Secondary Metabolites from Marine Bacillus Species: Chemistry and Biological Activity

    OpenAIRE

    Hee Jae Shin; Muhammad Abdul Mojid Mondol; Mohammad Tofazzal Islam

    2013-01-01

    Marine Bacillus species produce versatile secondary metabolites including lipopeptides, polypeptides, macrolactones, fatty acids, polyketides, and isocoumarins. These structurally diverse compounds exhibit a wide range of biological activities, such as antimicrobial, anticancer, and antialgal activities. Some marine Bacillus strains can detoxify heavy metals through reduction processes and have the ability to produce carotenoids. The present article reviews the chemistry and biological activi...

  9. ON THE ACTIVITY OF alpha-AMYLASE IN SOME SPECIES OF ASIAN CYPRINIDS

    Directory of Open Access Journals (Sweden)

    Gabriela Vasile

    2006-08-01

    amylase in two Asian cyprinids namely, bighead carp (Aristichthys nobilis and silver carp (Hypophthalmichthys molitrix. The activity of -amylase has been determined by the Métais-Bieth method, the results obtained being expressed as mg starch / ml x 30 min. Our experimental data evidence some differences between the activity of -amylase from the digestive tube, in the two species under study.

  10. Phenolic compounds and in vitro antioxidant activity of selected species of seaweeds from Danish coast

    DEFF Research Database (Denmark)

    Farvin, Sabeena; Jacobsen, Charlotte

    2013-01-01

    Water and ethanolic extracts of 16 species of seaweeds collected along the Danish coasts were screened for antioxidant activities using four in vitro antioxidant assays (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, reducing power, ferrous ion-chelating and liposome model system......). Furthermore their effectiveness in retarding lipid peroxidation in fish oil was evaluated by an accelerated stability test. Significant differences were observed in total and individual phenolic content and the antioxidant activities of seaweed species evaluated. Ethanol was more efficient for polyphenol...... extraction than water. Polysiphonia fucoides and all the Fucus species tested showed highest radical scavenging activity, reducing power, inhibition of oxidation in liposome model system and in fish oil and were high in phenolic content. These seaweeds could be potential rich sources of natural antioxidants...

  11. In vitro activity of Rutaceae species against the trypomastigote form of Trypanosoma cruzi.

    Science.gov (United States)

    Mafezoli, J; Vieira, P C; Fernandes, J B; da Silva, M F; de Albuquerque, S

    2000-11-01

    The activity of crude plant extracts of nine species of Rutaceae against the trypomastigote form of Trypanosoma cruzi was evaluated at 4 mg/ml. Thirty-two crude extracts were tested and eight of them showed significant activity (>80%). The most active extract was obtained from the stems of Pilocarpus spicatus (97.3%). Fractionation of the active crude extracts provided 25 fractions which were tested against the trypomastigote form of T. cruzi at 2 mg/ml. Of these six showed significant activity (>80%). The most active fractions (100%) were obtained from the leaves of Almeidea coerulea (butanol fraction) and Conchocarpus inopinatus (dichloromethane fraction). PMID:11025175

  12. Effects of pretreatment on the surface chemistry and pore size properties of nitrogen functionalized and alkylated granular activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jiajun [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Zhai Yunbo, E-mail: ybzhai@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Chen Hongmei; Li Caiting; Zeng Guangming; Pang Daoxiong; Lu Pei [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer The effects of pretreatment on the surface chemistry and pore sizes were studied. Black-Right-Pointing-Pointer Treated GAC was nitrogen functionalized and alkylated GAC also called modified GAC. Black-Right-Pointing-Pointer HNO{sub 3} pretreatment caused a slight decrease in surface area and microporosity. Black-Right-Pointing-Pointer The nitrogen percentage of modified GAC which pretreated by H{sub 2}O{sub 2} was 4.07%. Black-Right-Pointing-Pointer The pyridine of modified GAC which pretreated by urea-formaldehyde resin was 45.88%. - Abstract: In this paper, granular activated carbon (GAC) from coconut shell was pretreated by HNO{sub 3}, H{sub 2}O{sub 2} and urea-formaldehyde resin, respectively. Then the obtained materials were functionalized in the same way for nitrogen group, and then alkylated. Effects of pretreatment on the surface chemistry and pore size of modified GACs were studied. Surface area and micropore volume of modified GAC which pretreated by HNO{sub 3} were 723.88 m{sup 2}/g and 0.229 cm{sup 3}/g, respectively, while virgin GAC were 742.34 m{sup 2}/g and 0.276 cm{sup 3}/g. Surface area and micropore volume decrease of the modified GACs which pretreated by the others two methods were more drastically. The types of groups presented were analyzed by electrophoresis, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). N-CH{sub 3} group and C=N group were detected on the surfaces of these three kinds of modified GACs. Results of XPS showed that the nitrogen functions of modified GAC which pretreated by H{sub 2}O{sub 2} was 4.07%, it was more than that of the others two pretreatment methods. However, the modified GAC which pretreated by urea-formaldehyde resin was fixed more pyridine structure, which structure percentage was 45.88%, in addition, there were more basic groups or charge on the surface than the others.

  13. Ozone-biological activated carbon integrated treatment for removal of precursors of halogenated nitrogenous disinfection by-products.

    Science.gov (United States)

    Chu, Wenhai; Gao, Naiyun; Yin, Daqiang; Deng, Yang; Templeton, Michael R

    2012-03-01

    Pilot-scale tests were performed to reduce the formation of several nitrogenous and carbonaceous disinfection by-products (DBPs) with an integrated ozone and biological activated carbon (O(3)-BAC) treatment process following conventional water treatment processes (coagulation-sedimentation-filtration). Relative to the conventional processes alone, O(3)-BAC significantly improved the removal of turbidity, dissolved organic carbon, UV(254), NH(4)(+) and dissolved organic nitrogen from 98-99%, 58-72%, 31-53%, 16-93% and 35-74%, respectively, and enhanced the removal efficiency of the precursors for the measured DBPs. The conventional process was almost ineffective in removing the precursors of trichloronitromethane (TCNM) and dichloroacetamide (DCAcAm). Ozonation could not substantially reduce the formation of DCAcAm, and actually increased the formation potential of TCNM; it chemically altered the molecular structures of the precursors and increased the biodegradability of N-containing organic compounds. Consequently, the subsequent BAC filtration substantially reduced the formation of the both TCNM and DCAcAm, thus highlighting a synergistic effect of O(3) and BAC. Additionally, O(3)-BAC was effective at controlling the formation of the total organic halogen, which can be considered as an indicator of the formation of unidentified DBPs.

  14. Characterization and activity of visible-light-driven TiO 2 photocatalyst codoped with nitrogen and cerium

    Science.gov (United States)

    Liu, Chao; Tang, Xinhu; Mo, Cehui; Qiang, Zhimin

    2008-04-01

    Nitrogen and cerium codoped TiO 2 photocatalysts were prepared by a modified sol-gel process with doping precursors of cerium nitrate and urea, and characterized by X-ray diffraction (XRD), thermogravimetry-differential scanning calorimetry (TG-DSC), X-ray photoelectron spectra (XPS) and ultraviolet-visible light diffuse reflectance spectra (UV-vis DRS). Results indicate that anatase TiO 2 is the dominant crystalline type in as-prepared samples, and CeO 2 crystallites appear as the doping ratio of Ce/Ti reaches to 3.0 at%. The TiO 2 starts to transform from amorphous phase to anatase at 987.1 K during calcination, according to the TG-DSC curves. The XPS show that three major metal ions of Ce 3+, Ce 4+, Ti 4+ and one minor metal ion of Ti 3+ coexist on the surface. The codoped TiO 2 exhibits significant absorption within the range of 400-500 nm compared to the non-doped and only nitrogen-doped TiO 2. The enhanced photocatalytic activity of the codoped TiO 2 is demonstrated through degradation of methyl orange under visible light irradiation.

  15. Electrochemical preparation of nitrogen-doped graphene quantum dots and their size-dependent electrocatalytic activity for oxygen reduction

    Indian Academy of Sciences (India)

    Dhanraj B Shinde; Vishal M Dhavale; Sreekumar Kurungot; Vijayamohanan K Pillai

    2015-04-01

    Here we report a remarkable transformation of nitrogen-doped multiwalled carbon nanotubes (MWCNTs) to size selective nitrogen-doped graphene quantum dots (N-GQDs) by a two-step electrochemical method. The sizes of the N-GQDs strongly depend on the applied anodic potential, moreover increasing potential resulted in a smaller size of N-GQDs. These N-GQDs display many unusual size-dependant optoelectronic (blue emission) and electrocatalytic (oxygen reduction) properties. The presence of N dopants in the carbon framework not only causes faster unzipping of MWCNTs but also provides more low activation energy site for enhancing the electrocatalytic activity for technologically daunting reactions like oxygen reduction. The smaller size of N-GQDs has shown better performance as compared to the large N-GQDs. Interestingly, N-GQDs-3 (size = 2.5 ± 0.3 nm, onset potential = 0.75 V) show a 30-mV higher positive onset potential shift compared to that of N-GQDs-2 (size = 4.7 ± 0.3 nm, onset potential = 0.72 V) and 70 mV than that of N-GQDs-1 (size = 7.2 ± 0.3, onset potential = 0.68 V) for oxygen reduction reaction (ORR) in a liquid phase. These result in the size-dependent electrocatalytic activity of N-GQDs for ORR as illustrated by the smaller sized N-GQDs (2.5 ± 0.3 nm) undoubtedly promising metal-free electrocatalysts for fuel cell applications.

  16. Highly Visible Light Activity of Nitrogen Doped TiO2 Prepared by Sol-Gel Approach

    Science.gov (United States)

    Than, Le Dien; Luong, Ngo Sy; Ngo, Vu Dinh; Tien, Nguyen Manh; Dung, Ta Ngoc; Nghia, Nguyen Manh; Loc, Nguyen Thai; Thu, Vu Thi; Lam, Tran Dai

    2016-09-01

    A simple approach was explored to prepare N-doped anatase TiO2 nanoparticles (N-TiO2 NPs) from titanium chloride (TiCl4) and ammonia (NH3) via sol-gel method. The effects of important process parameters such as calcination temperatures, NH3/TiCl4 molar ratio (R N) on crystallite size, structure, phase transformation, and photocatalytic activity of titanium dioxide (TiO2) were thoroughly investigated. The as-prepared samples were characterized by ultraviolet-visible spectroscopy, x-ray diffraction, transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The photocatalytic activity of the samples was evaluated upon the degradation of methylene blue aqueous solution under visible-light irradiation. The results demonstrated that both calcination temperatures and NH3/TiCl4 molar ratios had significant impacts on the formation of crystallite nanostructures, physicochemical, as well as catalytic properties of the obtained TiO2. Under the studied conditions, calcination temperature of 600°C and NH3/TiCl4 molar ratio of 4.2 produced N-TiO2 with the best crystallinity and photocatalytic activity. The high visible light activity of the N-TiO2 nanomaterials was ascribed to the interstitial nitrogen atoms within TiO2 lattice units. These findings could provide a practical pathway capable of large-scale production of a visible light-active N-TiO2 photocatalyst.

  17. Chemical Constituents and Antibacterial and Antifungal Activities of Two Aglaia Species

    Institute of Scientific and Technical Information of China (English)

    WANG,Bin-Gui; LI,Xiao-Ming; PROKSCH,Peter

    2004-01-01

    @@ In the course of searching bioactive natural products from the plant genus Aglaia, we selected two species, A. cordata and A. testicularis, for further chemical study. Totally twenty natural compounds were obtained and structurally elucidated with which eleven of them were discovered for the first time. Among these compounds, lignans, rocaglamides,aglains and bisamides were the main constituents of the two plant species. The results from a bioactive screening indicated that some of the lignans possess potent antibacterial and antifungal activity.

  18. ANTI-INFLAMMATORY ACTIVITIES OF SOME SPECIES OF ANDROGRAPHIS WALL. (ACANTHACEAE)

    OpenAIRE

    Balu, S.; Alagesaboopathi, C.

    1993-01-01

    The anti – inflammatory activities of the alcoholic extracts of three species of Andrographis Wall. were assayed at a dose of 500 mg/kg body weight in Male albino rats using carrageenin induced rat paw edema. All the extracts were screened for their anti-inflammatory activities in Carrageenin induced inflammation in rats. The maximal anti-inflammatory activity was found with the alcoholic extract of Andrographis alata Nees.

  19. Interaction Induced High Catalytic Activities of CoO Nanoparticles Grown on Nitrogen-Doped Hollow Graphene Microspheres for Oxygen Reduction and Evolution Reactions

    Science.gov (United States)

    Jiang, Zhong-Jie; Jiang, Zhongqing

    2016-06-01

    Nitrogen doped graphene hollow microspheres (NGHSs) have been used as the supports for the growth of the CoO nanoparticles. The nitrogen doped structure favors the nucleation and growth of the CoO nanoparticles and the CoO nanoparticles are mostly anchored on the quaternary nitrogen doped sites of the NGHSs with good monodispersity since the higher electron density of the quaternary nitrogen favors the nucleation and growth of the CoO nanoparticles through its coordination and electrostatic interactions with the Co2+ ions. The resulting NGHSs supported CoO nanoparticles (CoO/NGHSs) are highly active for the oxygen reduction reaction (ORR) with activity and stability higher than the Pt/C and for the oxygen evolution reaction (OER) with activity and stability comparable to the most efficient catalysts reported to date. This indicates that the CoO/NGHSs could be used as efficient bi-functional catalysts for ORR and OER. Systematic analysis shows that the superior catalytic activities of the CoO/NGHSs for ORR and OER mainly originate from the nitrogen doped structure of the NGHSs, the small size of the CoO nanoparticles, the higher specific and electroactive surface area of the CoO/NGHSs, the good electric conductivity of the CoO/NGHSs, the strong interaction between the CoO nanoparticles and the NGHSs, etc.

  20. Chemistry and biological activities of essential oils from Melaleuca L. species

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Almeida Barbosa

    2013-03-01

    Full Text Available Essential oils from species Melaleuca genus, especially M. alternifolia (Maiden & Betche Cheel, have been widely used worldwide in various industries. This review is a contribution to Melaleuca knowledge and describes five important essential oil-producing species and two subspecies of Melaleuca in terms of their essential oil chemical composition, medicinal applications, and leaf morphoanatomy. Some relationships between essential oil composition of these species and important biological activities are presented. Useful parameters for the certification of the essential oils are also highlighted.

  1. Chemistry and Biological Activities of Essential Oils from Melaleuca L. Species

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Almeida Barbosa

    2013-03-01

    Full Text Available Essential oils from species Melaleuca genus, especially M. alternifolia (Maiden & Betche Cheel, have been widely used worldwide in various industries. This review is a contribution to Melaleuca knowledge and describes five important essential oil-producing species and two subspecies of Melaleuca in terms of their essential oil chemical composition, medicinal applications, and leaf morphoanatomy. Some relationships between essential oil composition of these species and important biological activities are presented. Useful parameters for the certification of the essential oils are also highlighted.

  2. Nitrogen nutrition of Salvinia natans: Effects of inorganic nitrogen form on growth, morphology, nitrate reductase activity and uptake kinetics of ammonium and nitrate

    DEFF Research Database (Denmark)

    Jampeetong, Arunothai; Brix, Hans

    2009-01-01

    In this study we assessed the growth, morphological responses, and N uptake kinetics of Salvinia natans when supplied with nitrogen as NO3-, NH4+, or both at equimolar concentrations (500 μM). Plants supplied with only NO3- had lower growth rates (0.17 ± 0.01 g g-1 d-1), shorter roots, smaller le...

  3. Leaf life span and nitrogen content in semideciduous forest tree species (Croton priscus and Hymenaea courbaril Duração da vida da folha e conteúdo de nitrogênio em espécies arbóreas (Croton priscus e Hymenaea courbaril de floresta semidecídua

    Directory of Open Access Journals (Sweden)

    Claudia Regina Baptista Haddad

    2004-01-01

    Full Text Available In comparison to deciduous species, evergreen plants have lower leaf nutrient contents and higher leaf life span, important mechanisms for nutrient economy, allowing the colonization of low fertility soils. Strategies to conserve nitrogen in two semideciduous tropical forest tree species, with different leaf life spans were analyzed. The hypothesis was the fact that the two species would present different nitrogen conservation mechanisms in relation to chemical (total nitrogen, protein, chlorophyll, and proteolytic activity, functional (leaf life span, N-use efficiency, and N-resorption efficiency, morphological (specific leaf mass leaf characteristics, and total nitrogen in the soil. Hymenaea courbaril L. presented lower nitrogen compounds in leaves, longer leaf life span, higher N-use efficiency, and higher specific leaf mass, while absorbing proportionally less nitrogen from the soil than Croton priscus Croizat. These characteristics can contribute for a better nitrogen economy strategy of H. courbaril. No relationship was found between leaf life span and N resorption efficiency, nor between leaf life span, protease activity and nitrogen mobilization. The electrophoretic profiles of proteolytic enzymes in young leaves of the two species presented more bands with enzymatic activity than other kinds of leaves.Comparadas a espécies decíduas, as sempre-verdes têm menos nutrientes nas folhas, que também são mais longevas. Estes mecanismos são importantes para economia de nutrientes, e permitem a colonização de solos com baixa fertilidade. Foram analisadas estratégias de conservação de nitrogênio em duas espécies de floresta semidecídua, que aparentemente apresentavam longevidades foliares diferentes. Para isto foram comparados mecanismos químicos (concentrações de nitrogênio total, de proteína e clorofila e atividade proteolítica, funcionais (duração de vida das folhas, eficiência do uso de nitrogênio e eficiência de

  4. Comparative in vitro metabolism and activation of benzo(a)pyrene from two species of catfish

    Energy Technology Data Exchange (ETDEWEB)

    Ploch, S.A.; Di Giulio, R.T. [Duke Univ., Durham, NC (United States)

    1995-12-31

    Cytochrome P4501A activity as measured by hepatic ethoxyresorufin-O-deethylase EROD in isolated microsomes is consistently found to be 10 to 20 fold higher in channel catfish (Ictalurus punctuatus) than in a closely related species of catfish, the brown bullhead (Ameriurus nebulosus). To measure more directly the ability of these two species to activate a model PAH, microsomes and hepatocytes isolated from naphthoflavone induced channel catfish (CC) and brown bullhead (BB) were incubated with [{sup 3}H]- or [{sup 14}C]benzo(a)pyrene (BP) to compare metabolite formation and binding to DNA and protein. Microsomes from channel catfish produce 4-fold higher levels of BP metabolites (hexane non-extractable) than brown bullhead (253.0, 9.0 vs 58.8, 14.9 pmole/mg, protein/min). Binding of microsome activated BP to salmon sperm DNA demonstrated a similar 5-fold difference between the two species. Using isolated hepatocytes, the two species demonstrated less pronounced, but consistent differences in metabolite formation (29.85, 2.2 vs 20.1, 0.96 pmole/10{sup 6}, cells/min, CC vs BB), DNA binding and total protein binding (13.2, 2.53 vs 10.57, 1.72 pmole BP/mg, protein/min, CC vs BB). Surprisingly, these preliminary data suggest that induced CC liver activate a model PAH carcinogen more quickly and produce higher levels of stable adducts than a cancer prone species (brown bullhead). Other aspects of BP activation, detoxification and genotoxicity in these two species may contribute to species` susceptibility to carcinogenesis.

  5. The Importance of Landscape Elements for Bat Activity and Species Richness in Agricultural Areas.

    Directory of Open Access Journals (Sweden)

    Olga Heim

    Full Text Available Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat activity and species richness were assessed using repeated monitoring from May to September in 2010 with acoustic monitoring surveys on 50 grassland sites in the Biosphere Reserve Schorfheide-Chorin (North-East Germany. Using spatial analysis (GIS, we measured the closest distance of each grassland site to potentially connecting landscape elements (e.g., trees, linear vegetation, groves, running and standing water. In addition, we assessed the distance to and the percent land cover of forest remnants and urban areas in a 200 m buffer around the recording sites to address differences in the local landscape setting. Species richness and bat activity increased significantly with higher forest land cover in the 200 m buffer and at smaller distance to forested areas. Moreover, species richness increased in proximity to tree groves. Larger amount of forest land cover and smaller distance to forest also resulted in a higher activity of bats on grassland sites in the beginning of the year during May, June and July. Landscape elements near grassland sites also influenced species composition of bats and species richness of functional groups (open, edge and narrow space foragers. Our results highlight the importance of forested areas, and suggest that agricultural grasslands that are closer to forest remnants might be better buffered against outbreaks of agricultural pest insects due to higher species richness and higher bat activity. Furthermore, our data reveals that even for highly mobile species such as bats, a very dense network of connecting elements within the

  6. The Importance of Landscape Elements for Bat Activity and Species Richness in Agricultural Areas.

    Science.gov (United States)

    Heim, Olga; Treitler, Julia T; Tschapka, Marco; Knörnschild, Mirjam; Jung, Kirsten

    2015-01-01

    Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat activity and species richness were assessed using repeated monitoring from May to September in 2010 with acoustic monitoring surveys on 50 grassland sites in the Biosphere Reserve Schorfheide-Chorin (North-East Germany). Using spatial analysis (GIS), we measured the closest distance of each grassland site to potentially connecting landscape elements (e.g., trees, linear vegetation, groves, running and standing water). In addition, we assessed the distance to and the percent land cover of forest remnants and urban areas in a 200 m buffer around the recording sites to address differences in the local landscape setting. Species richness and bat activity increased significantly with higher forest land cover in the 200 m buffer and at smaller distance to forested areas. Moreover, species richness increased in proximity to tree groves. Larger amount of forest land cover and smaller distance to forest also resulted in a higher activity of bats on grassland sites in the beginning of the year during May, June and July. Landscape elements near grassland sites also influenced species composition of bats and species richness of functional groups (open, edge and narrow space foragers). Our results highlight the importance of forested areas, and suggest that agricultural grasslands that are closer to forest remnants might be better buffered against outbreaks of agricultural pest insects due to higher species richness and higher bat activity. Furthermore, our data reveals that even for highly mobile species such as bats, a very dense network of connecting elements within the landscape is

  7. Influence of nitrogen hetero-substitution on the electrochemical performance of coal-based activated carbons measured in non-aqueous electrolyte

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chuan-xiang; DUAN Yu-ling; XING Bao-lin; ZHAN Liang; QIAO Wen-ming; LING Li-cheng

    2009-01-01

    Nitrogen-containing carbons were prepared by modification of activated carbons. The modified carbons were used as electrode materials with improved electrochemical performance. Precursor anthracite was activated by KOH (KOH: anthracite= 1:1), modified by melamine or urea and then treated at 1173 K to obtain the modified carbons. The porous structure, the chemical composition and the electrochemical characteristics of the carbons were investigated by nitrogen sorption, XPS and electrochemical methods respectively. Electrochemical experiments were performed in an organic electrolytic solution of 1 M (C2H5)4NBF4/PC.The samples modified by the different methods showed differences in chemical composition that introduced varying degrees of electrochemical performance enhancement. The presence of nitrogen enhanced the electron donor properties and the surface wettability of the activated carbons: this ensured a sufficient utilization of the exposed surface for charge storage.

  8. Nitrosation, nitration, and autoxidation of the selective estrogen receptor modulator raloxifene by nitric oxide, peroxynitrite, and reactive nitrogen/oxygen species.

    Science.gov (United States)

    Toader, Violeta; Xu, Xudong; Nicolescu, Adrian; Yu, Linning; Bolton, Judy L; Thatcher, Gregory R J

    2003-10-01

    The regulation of estrogenic and antiestrogenic effects by selective estrogen receptor modulators (SERMs) provides the basis for use in long-term therapy in cancer chemoprevention and postmenopausal osteoporosis. However, the evidence for carcinogenic properties within this class requires study of potential pathways of toxicity. There is strong evidence for the elevation of cellular levels of NO in tissue treated with SERMs, including the benzothiophene derivative, raloxifene, in part via up-regulation of nitric oxide synthases. Therefore, the reactions of 17beta-estradiol (E(2)), raloxifene, and an isomer with NO, peroxynitrite, and reactive nitrogen/oxygen species (RNOS) generated from NO(2)(-)/H(2)O(2) systems were examined. Peroxynitrite from bolus injection or slow release from higher concentrations of 3-morpholinosydnonimine (SIN-1) reacted with the benzothiophenes and E(2) to give aromatic ring nitration, whereas peroxynitrite, produced from the slow decomposition of lower concentrations of SIN-1, was relatively unreactive toward E(2) and yielded oxidation and nitrosation products with raloxifene and its isomer. The oxidation and nitrosation products formed were characterized as a dimer and quinone oxime derivative. Interestingly, the reaction of the benzothiophenes with NO in aerobic solution efficiently generated the same oxidation products. Stable quinone oximes are not unprecedented but have not been previously reported as products of RNOS-mediated metabolism. The reaction of glutathione (GSH) with the quinone oxime gave both GSH adducts from Michael addition and reduction to the corresponding o-aminophenol. The ready autoxidation of raloxifene, observed in the presence of NO, is the first such observation on the reactivity of SERMs and is potentially a general phenomenon of significance to SERM chemical toxicology. PMID:14565768

  9. A STUDY OF ANTIMICROBIAL ACTIVITY OF ETHANOLIC EXTRACTS OF VARIOUS PLANT LEAVES AGAINST SELECTED MICROBIAL SPECIES

    Directory of Open Access Journals (Sweden)

    K.Valarmathy,

    2010-09-01

    Full Text Available To evaluate the antimicrobial activities of extract of leaves were examined against four common bacterial isolates. The ethanolic extracts of various leaves such as Moringa oleifera (Murungai , Musa paradisiaca (Banana, Azardiratica indica (Neem, Cynodon dactylon(Grass, Alternanthera sessilis (Ponnangkani, Anisochilus carnosus (Karpooravalli, investigated individually for antimicrobial activity by disc diffusion method .These were investigated against selected species of Escherichia coli, Bacillus subtilis, Vibrio cholerae, Klebsiella pneumoniae to find the inhibitory activities of the microbes. The ethanolic extract of Azardiratica indica showed considerably high activity against Escherichia coli than other extracts. These results were compared with standard antibiotic Penicillin. But the extract showed higher activity than the given standard antibiotic.

  10. Screening of medicinal natural extracts for their antibacterial activity against salmonella species

    International Nuclear Information System (INIS)

    The present study was aimed to screen out natural crude extracts exhibiting antibacterial activity against Salmonella causing gastrointestinal problems in humans. Fifteen Salmonella species were isolated from uncooked chicken, polluted water, rotten potatoes, beef, rotten eggs etc. Aqueous plant extracts of Allium sativum (garlic), Nigella sativa (kalvanji), Azadirachta indica (neem), Ficus carica (anjeer), and Trigonella foenum-graecum (methi) were checked against Salmonella species by well plate method. In addition to plant extract, Honey was also used for antibacterial activity. Inhibition zones ranging from 2mm to 20mm were obtained with different concentration of plant extracts and honey. The antibacterial sensitivity pattern was in the order of kalvanji > garlic > honey > anjeer > methi > neem. The standard antibiotics such as Ceftriaxone and Ciprofloxacin were also used for comparison with natural extract for antibacterial activity. The extracts of Allium sativum, Nigella sativa and Honey were found to be more effective against Salmonella species for which even Ceftriaxone was found ineffective. (author)

  11. EVALUATION OF ANTIOXIDANT ACTIVITY IN ETHANOLIC EXTRACTS OF FIVE CURCUMA SPECIES

    Directory of Open Access Journals (Sweden)

    Gayatri Nahak

    2011-12-01

    Full Text Available The Zingiberaceae, the largest family in the Zingiberales, comprises nearly 50 genera and 1,000 species and is pantropical, concentrated mainly in the old world, chiefly in Indo-malaysia. Members of the family yield spices, dyes, perfumes, medicines and a number of ornamental species are cultivated for their showy flowers. Recently this plant has acquired great importance in the present-day world with its antiaging, anticancer, anti-alzheimer’s diseases, antioxidant, and a variety of other medicinal properties due to its significant potential. The present study aims at comparing the antioxidant activity of five Curcuma species namely Curcuma longa, Curcuma zedoaria, Curcuma angustifolia, Curcuma aromatica and Curcuma amada based on their curcumin and phenol content. In our studying C.longa exhibited the highest antioxidant activity 74.61±0.02% at IC50 value 24µg/ml followed by C.zedoaria (63.27±0.06%, C.angustifolia (58.35±0.06%, C.aromatica (55.38±0.06% and C.amada (52.61±0.02%. Antioxidant activity in four species except C.angustifolia has strong correlation with curcumin and phenol content. However C.angustifolia may be active due to high aromatic oil content like eugenol, palmitic and camphor etc. The natural oxides of curcuma species can be explained in the field of pharmaceutical areas for their uses in modern health care as phytoprotectants.

  12. Synthesis and Antimicrobial Activity of New 4-Heteroarylamino Coumarin Derivatives Containing Nitrogen and Sulfur as Heteroatoms

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    Biljana R. Dekić

    2010-03-01

    Full Text Available Synthesis, spectral analysis and bioactivity of new coumarin derivatives are described in this paper. Eight new coumarin derivatives were synthesized in moderate to good yields by condensation of 4-chloro-3-nitrocoumarin and the corresponding heteroarylamine. The synthesized compounds were tested for their in vitro antimicrobial activity, in a standard disk diffusion assay, against thirteen strains of bacteria and three fungal strains. They have shown a wide range of activity - from one completely inactive compound to medium active ones.

  13. Efficiency of active barriers attaching biofilm as sediment capping to eliminate the internal nitrogen in eutrophic lake and canal

    Institute of Scientific and Technical Information of China (English)

    Tinglin Huang; Jinlan Xu; Daojian Cai

    2011-01-01

    Three active barrier materials (zeolite, ceramicite and light porous media) were applied for preventing nitrogen (N) release from eutrophic lake sediments. Long term experiment of two different lake sediments were carried out and the effect of zeolite dose was evaluated. The results indicated that about 90%-100% of total N in overlying water was eliminated by using zeolite. While the N removal efficiency by ceramic was lower than that by zeolite, and light porous media present the lowest efficiency of 59%. Long term sediment incubation experiments indicated that two eutrophic sediments were both effective in preventing N release in spite of different release characteristics. Bio-zeolite capping technology was able to effectively inhibit the release of N from the sediment, and the zeolite dose was independently from N removal.

  14. Evaluation of clinoptilolite for removal of ammoniacal nitrogen produced in aquaculture by Neutron activation analysis and UV-VIS spectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    Bibiano C, L.; Iturbe G, J.L.; Lopez M, B.E.; Martinez M, V. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    In fish culture system, ammonia is excreted in the water as a metabolic by-product. In this work, sorption properties of clinoptilolite were determined and it was applied in culture of the rainbow trout Oncorhynchus mykiss for the removal of the ammoniacal nitrogen. The original clinoptilolite was treated with 1N NaCl solution from 24 to 192 h, for exchange NH{sub 4} ions produced in fish culture. The content of Na in the clinoptilolite was determined by neutron activation analysis. The ammonium ion content in the exchange was analysed by UV-VIS spectrophotometry. Maximum uptake of sodium was reached between 24 and 48 hours at neutral pH with granules of the clinoptilolite from 14 to 24 mesh size. The adsorption capacity was from 3.28 to 6.8 mg of ammonium per gram of clinoptilolite. (Author)

  15. Manganese oxide-induced strategy to high-performance iron/nitrogen/carbon electrocatalysts with highly exposed active sites

    Science.gov (United States)

    Sun, Tao; Wu, Qiang; Zhuo, Ou; Jiang, Yufei; Bu, Yongfeng; Yang, Lijun; Wang, Xizhang; Hu, Zheng

    2016-04-01

    Iron/nitrogen/carbon (Fe/N/C) catalyst is so far the most promising non-precious metal electrocatalyst for oxygen reduction reaction (ORR) in acidic medium, whose performance depends closely on the synthesis chemistry. Herein, we report a MnOx-induced strategy to construct the Fe/N/C with highly exposed Fe-Nx active sites, which involves the uniform spreading of polyaniline on hierarchical N-doped carbon nanocages by a reactive-template polymerization, followed by the successive iron incorporation and polyaniline pyrolysis. The resulting Fe/N/C demonstrates an excellent ORR performance, including an onset potential of 0.92 V (vs. RHE), four electron selectivity, superb stability and immunity to methanol crossover. The excellent performance is well correlated with the greatly enhanced surface active sites of the catalyst stemming from the unique MnOx-induced strategy. This study provides an efficient approach for exploring the advanced ORR electrocatalysts by increasing the exposed active sites.Iron/nitrogen/carbon (Fe/N/C) catalyst is so far the most promising non-precious metal electrocatalyst for oxygen reduction reaction (ORR) in acidic medium, whose performance depends closely on the synthesis chemistry. Herein, we report a MnOx-induced strategy to construct the Fe/N/C with highly exposed Fe-Nx active sites, which involves the uniform spreading of polyaniline on hierarchical N-doped carbon nanocages by a reactive-template polymerization, followed by the successive iron incorporation and polyaniline pyrolysis. The resulting Fe/N/C demonstrates an excellent ORR performance, including an onset potential of 0.92 V (vs. RHE), four electron selectivity, superb stability and immunity to methanol crossover. The excellent performance is well correlated with the greatly enhanced surface active sites of the catalyst stemming from the unique MnOx-induced strategy. This study provides an efficient approach for exploring the advanced ORR electrocatalysts by increasing the

  16. Nitrogen trading tool

    Science.gov (United States)

    The nitrogen cycle is impacted by human activities, including those that increase the use of nitrogen in agricultural systems, and this impact can be seen in effects such as increased nitrate (NO3) levels in groundwater or surface water resources, increased concentration of nitrous oxide (N2O) in th...

  17. The changes of the polyphenol content and antioxidant activity in potato tubers (Solanum tuberosum L. due to nitrogen fertilization

    Directory of Open Access Journals (Sweden)

    Diana Hrabovská

    2013-11-01

    Full Text Available 96 Normal 0 false false false CS JA X-NONE Cultivar is one of the most important internal factors affecting polyphenol concentration in the plants. However, influence of the grown locality, climate conditions and way of cultivation belong to important external factors. In our experiment the influence of different nitrogen doses (0 - 40 - 80 - 120 - 160 - 240 kg N.ha-1 applied in the form of Vermikompost on the total polyphenol content and derived total antioxidant activity in cv. Sorento were investigated. While in the 1st - 5th variants the determined polyphenol content in dry mater of potato tubers decreased from 399.2 to 70.40 mg.kg-1, in the 6th variant that was twice higher in comparison to the 5th variants (135.6 mg.kg-1. The statistically significant differences in values of total polyphenol content between variants (polynomial function of 2nd degree were confirmed. The study also confirmed a strong statistical correlation between the content of polyphenols and the content of antioxidant activity has been confirmed (sign. F: 3.24E-10. The highest value of antioxidant activity was observed in the first variant. From the first to the fifth variant (7.62 - 4.84%, the value of antioxidant activity was decreasing and in the sixth variant this value increased to 6.31%.

  18. Photosystem II cycle activity and alternative electron transport in the diatom Phaeodactylum tricornutum under dynamic light conditions and nitrogen limitation.

    Science.gov (United States)

    Wagner, Heiko; Jakob, Torsten; Lavaud, Johann; Wilhelm, Christian

    2016-05-01

    Alternative electron sinks are an important regulatory mechanism to dissipate excessively absorbed light energy particularly under fast changing dynamic light conditions. In diatoms, the cyclic electron transport (CET) around Photosystem II (PS II) is an alternative electron transport pathway (AET) that contributes to avoidance of overexcitation under high light illumination. The combination of nitrogen limitation and high-intensity irradiance regularly occurs under natural conditions and is expected to force the imbalance between light absorption and the metabolic use of light energy. The present study demonstrates that under N limitation, the amount of AET and the activity of CETPSII in the diatom Phaeodactylum tricornutum were increased. Thereby, the activity of CETPSII was linearly correlated with the amount of AET rates. It is concluded that CETPSII significantly contributes to AET in P. tricornutum. Surprisingly, CETPSII was found to be activated already at the end of the dark period under N-limited conditions. This coincided with a significantly increased degree of reduction of the plastoquinone (PQ) pool. The analysis of the macromolecular composition of cells of P. tricornutum under N-limited conditions revealed a carbon allocation in favor of carbohydrates during the light period and their degradation during the dark phase. A possible linkage between the activity of CETPSII and degree of reduction of the PQ pool on the one side and the macromolecular changes on the other is discussed. PMID:26650230

  19. Impact of carbon on the surface and activity of silica-carbon supported copper catalysts for reduction of nitrogen oxides

    Science.gov (United States)

    Spassova, I.; Stoeva, N.; Nickolov, R.; Atanasova, G.; Khristova, M.

    2016-04-01

    Composite catalysts, prepared by one or more active components supported on a support are of interest because of the possible interaction between the catalytic components and the support materials. The supports of combined hydrophilic-hydrophobic type may influence how these materials maintain an active phase and as a result a possible cooperation between active components and the support material could occur and affects the catalytic behavior. Silica-carbon nanocomposites were prepared by sol-gel, using different in specific surface areas and porous texture carbon materials. Catalysts were obtained after copper deposition on these composites. The nanocomposites and the catalysts were characterized by nitrogen adsorption, TG, XRD, TEM- HRTEM, H2-TPR, and XPS. The nature of the carbon predetermines the composite's texture. The IEPs of carbon materials and silica is a force of composites formation and determines the respective distribution of the silica and carbon components on the surface of the composites. Copper deposition over the investigated silica-carbon composites leads to formation of active phases in which copper is in different oxidation states. The reduction of NO with CO proceeds by different paths on different catalysts due to the textural differences of the composites, maintaining different surface composition and oxidation states of copper.

  20. Effect of co-existing plant specie on soil microbial activity under heavy metal stress

    International Nuclear Information System (INIS)

    The influence of plant primary compounds on the activity of soil microbial communities under heavy metal stress was studied in a pot-culture field experiment conducted in a green house. Amaranthus spinosus was cultivated in an agricultural soil previously amended in the laboratory with solutions of different trace elements in two separate treatment modes: singly and in combination. Culture-independent metabolism based indices such as the rate of carbon and nitrogen mineralization, microbial biomass carbon and soil basal respiration were monitored fortnightly over a period of six weeks. Result shows that plant detritus have significant modifying effect on soil microbe-metal interactions. Data on microbial and biochemical processes in the respective mesocosms did not vary from control; not even in mesocosms containing very high concentrations of copper, zinc and nickel. The soil microbial biomass carbon and the rate of carbon and nitrogen cycling were not impeded by the respective metal treatment while the respiration responses increased as a result of increase in metabolic activity of the soil microbes. The plant based substrates enabled the soil microflora to resist high metal contamination because of its tendency to absorb large amounts of inorganic cations.

  1. Determination of the antibiofilm, antiadhesive, and anti-MRSA activities of seven Salvia species

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    Amal G Al-Bakri

    2010-01-01

    Full Text Available Background: Several Salvia species are indigenous to Jordan and are widely used as beverages and spices and for their medicinal properties. The objective of the study was to establish the antimicrobial activities, including the antiadhesive and antibiofilm effects of seven different Salvia species. Materials and Methods: Methods used for planktonic culture included agar diffusion, broth microdilution, and minimal biocidal concentration determination while viable count was used for the determination of the antibiofilm and antiadhesion activities. Overnight cultures of reference strains of Candida albicans, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus and clinical strains of methicillin-resistant S. aureus (MRSA were used as test microorganisms. Results: An antimicrobial activity toward planktonic cultures demonstrated a significant bacteriocidal activity (≥4 log cycle reduction for the S. triloba extract against S. aureus including MRSA. Its volatile oil exhibited an antimicrobial activity covering all tested microorganisms with the exception of P. aeruginosa. S. triloba extract and volatile oil were successful in preventing and controlling the biofilm, demonstrating antiadhesion and antibiofilm activities, respectively. Conclusion: These reported activities for S. triloba extract and volatile oil allows their listing as potential antibiofilm and anti-MRSA natural agents. This might suggest their use as an antiseptic in the prophylaxis and treatment of S. aureus-associated skin infections. The antimicrobial activity of the other tested Salvia species was negligible.

  2. Effects of farmyard manure and nitrogen fertilizers on mobility of phosphorus and sulphur in wheat and activity of selected hydrolases in soil

    Science.gov (United States)

    Lemanowicz, Joanna; Siwik-Ziomek, Anetta; Koper, Jan

    2014-03-01

    The paper demonstrates the results of research on the mobility of phosphorus and sulphur in winter wheat fertilized with several rates (0, 20, 40, 60, 80 t ha-1) of farmyard manure and nitrogen (0, 40, 80, 120 kg N ha-1). The content of these nutrients was related to the activity of acid phosphatase and arylsulphatase in a Haplic Luvisol. The highest content of available phosphorus (91.58 mg P kg-1) was reported in the soil amended with farmyard manure at the rate of 60 t ha-1. The content of sulphates (VI) in the Haplic Luvisol was high and, on average, equal to 25.22 mg kg-1. The activity of acid phosphatase in the soil increased with increasing mineral nitrogen rates. The highest content of sulphates (VI) and the lowest activity of arylsulphatase were identified at the nitrogen rate of 40 kg N ha-1. The mobility of phosphorus in winter wheat was the highest when farmyard manure at the rate of 60 t ha-1 and mineral nitrogen at the rate of 120 kg N ha-1 were incorporated into the soil. The greatest translocation of sulphur was reported at the high farmyard manure rates (40, 60 and 80 t ha-1) and the nitrogen rate of 80 kg N ha-1.

  3. Responses of soil microbial communities and enzyme activities to nitrogen and phosphorus additions in Chinese fir plantations of subtropical China

    Science.gov (United States)

    Dong, W. Y.; Zhang, X. Y.; Liu, X. Y.; Fu, X. L.; Chen, F. S.; Wang, H. M.; Sun, X. M.; Wen, X. F.

    2015-09-01

    Nitrogen (N) and phosphorus (P) additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG) in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP) activity was always higher (57 and 71 %, respectively) in the P treatment. N and P additions greatly enhanced the phospholipid fatty acids (PLFAs) abundance especially in the N2P (100 kg ha-1 yr-1 of N +50 kg ha-1 yr-1 of P) treatment; the bacterial PLFAs (bacPLFAs), fungal PLFAs (funPLFAs) and actinomycic PLFAs (actPLFAs) were about 2.5, 3 and 4 times higher, respectively, than in the CK (control). Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC). βG or NAG activities were significantly and positively correlated with microbial PLFAs. These findings indicate that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote soil fertility and microbial activity in this kind of plantation.

  4. Response of hydrolytic enzyme activities and nitrogen mineralization to fertilizer and organic matter application in subtropical paddy soils

    Science.gov (United States)

    Kader, Mohammed Abdul; Yeasmin, Sabina; Akter, Masuda; Sleutel, Steven

    2016-04-01

    Driving controllers of nitrogen (N) mineralization in paddy soils, especially under anaerobic soil conditions, remain elusive. The influence of exogenous organic matter (OM) and fertilizer application on the activities of five relevant enzymes (β-glucosaminidase, β-glucosidase, L-glutaminase, urease and arylamidase) was measured in two long-term field experiments. One 18-years field experiment was established on a weathered terrace soil with a rice-wheat crop rotation at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) having five OM treatments combined with two mineral N fertilizer levels. Another 30-years experiment was established on a young floodplain soil with rice-rice crop rotation at the Bangladesh Agricultural University (BAU) having eight mineral fertilizer treatments combined with organic manure. At BSMRAU, N fertilizer and OM amendments significantly increased all enzyme activities, suggesting them to be primarily determined by substrate availability. At BAU, non-responsiveness of β-glucosidase activity suggested little effect of the studied fertilizer and OM amendments on general soil microbial activity. Notwithstanding probably equal microbial demand for N, β-glucosaminidase and L-glutaminase activities differed significantly among the treatments (P>0.05) and followed strikingly opposite trends and correlations with soil organic N mineralization. So enzymatic pathways to acquire N differed by treatment at BAU, indicating differences in soil N quality and bio-availability. L-glutaminase activity was significantly positively correlated to the aerobic and anaerobic N mineralization rates at both field experiments. Combined with negative correlations between β-glucosaminidase activity and N mineralization rates, it appears that terminal amino acid NH2 hydrolysis was a rate-limiting step for soil N mineralization at BAU. Future investigations with joint quantification of polyphenol accumulation and binding of N, alongside an

  5. Reactive oxygen species in signalling the transcriptional activation of WIPK expression in tobacco.

    Science.gov (United States)

    Xu, Juan; Yang, Kwang-Yeol; Yoo, Seung Jin; Liu, Yidong; Ren, Dongtao; Zhang, Shuqun

    2014-07-01

    Plant mitogen-activated protein kinases represented by tobacco WIPK (wounding-induced protein kinase) and its orthologs in other species are unique in their regulation at transcriptional level in response to stress and pathogen infection. We previously demonstrated that transcriptional activation of WIPK is essential for induced WIPK activity, and activation of salicylic acid-induced protein kinase (SIPK) by the constitutively active NtMEK2(DD) is sufficient to induce WIPK gene expression. Here, we report that the effect of SIPK on WIPK gene expression is mediated by reactive oxygen species (ROS). Using a combination of pharmacological and gain-of-function transgenic approaches, we studied the relationship among SIPK activation, WIPK gene activation in response to fungal cryptogein, light-dependent ROS generation in chloroplasts, and ROS generated via NADPH oxidase. In the conditional gain-of-function GVG-NtMEK2(DD) transgenic tobacco, induction of WIPK expression is dependent on the ROS generation in chloroplasts. Consistently, methyl viologen, an inducer of ROS generation in chloroplasts, highly activated WIPK expression. In addition to chloroplast-originated ROS, H(2)O(2) generated from the cell-surface NADPH oxidase could also activate WIPK gene expression, and inhibition of cryptogein-induced ROS generation also abolished WIPK gene activation. Our data demonstrate that WIPK gene activation is mediated by ROS, which provides a mechanism by which ROS influence cellular signalling processes in plant stress/defence response.

  6. Studies on the effect of long-term exposure to nitrogen dioxide on serum and liver proteins level and enzyme activity in guinea pigs.

    Science.gov (United States)

    Drozdz, M; Kucharz, E; Ludyga, K; Molska-Drozda, T

    1976-01-01

    Forty male guinea pigs were exposed to nitrogen dioxide in a concentration of 2 mg/m3, 8 hours daily for a period of 180 days. Forty male animals were used as a control group. The following changes were found in intoxicated animals: the decrease of total protein and seromucoid concentration in blood serum and the decrease of total protein, perchloric acid-soluble proteins, protein-bound hexosamines and sialic acids content, in liver tissue. Electrophoretic examination of the serum proteins showed the increase of alpha 1- and beta 2-globulins and the decrease of albumin concentration. Changes in the level of glycoproteins fractions and protein-bound carbohydrates in blood serum were described also. Estimation of enzymes activity showed the decrease of alanine and aspartate transaminase activity in blood serum caused by the strong decrease of the cytoplasmic fraction of these enzymes. However the simultaneous increase of the mitochondrial fraction of transaminases activity was observed. The decrease of the activity of choline esterase was found also. Similar changes of enzymes activity were found in liver tissue. Histopathological studies were done for the further clearing the influenze of nitrogen dioxide on serum and liver proteins concentration and enzymes activity. It was found that after long-term exposure to nitrogen dioxide the destruction processes may be observed in the liver. The possible mechanism of the nitrogen dioxide-induced damage of protein metabolism is discussed.

  7. Characterization of Serum Phospholipase A2 Activity in Three Diverse Species of West African Crocodiles

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    Mark Merchant

    2011-01-01

    Full Text Available Secretory phospholipase A2, an enzyme that exhibits substantial immunological activity, was measured in the serum of three species of diverse West African crocodiles. Incubation of different volumes of crocodile serum with bacteria labeled with a fluorescent fatty acid in the sn-2 position of membrane lipids resulted in a volume-dependent liberation of fluorescent probe. Serum from the Nile crocodile (Crocodylus niloticus exhibited slightly higher activity than that of the slender-snouted crocodile (Mecistops cataphractus and the African dwarf crocodile (Osteolaemus tetraspis. Product formation was inhibited by BPB, a specific PLA2 inhibitor, confirming that the activity was a direct result of the presence of serum PLA2. Kinetic analysis showed that C. niloticus serum produced product more rapidly than M. cataphractus or O. tetraspis. Serum from all three species exhibited temperature-dependent PLA2 activities but with slightly different thermal profiles. All three crocodilian species showed high levels of activity against eight different species of bacteria.

  8. ANTIULCER ACTIVITY OF ETHANOLIC LEAF EXTRACTS OF THREE VIBURNUM LINN. SPECIES – A COMPARATIVE EVALUATION

    Directory of Open Access Journals (Sweden)

    K Prabhu

    2011-03-01

    Full Text Available The genus, Viburnum Linn., belonging to the family, Adoxaceae (formerly positioned under the family - Caprifoliaceae, has been surveyed to cover about 200 species, in the world, and about 17 of them in India, especially, at an altitude from 800 – 2500 ft, habitat such as Himalaya and Nilgiri hills. The stem parts of these species claim to contain an appreciable quantity of therapeutically valuable phenolic compounds like anthocyanins, phenolic acids, flavones, flavonols and biflavone, and their glycosides. Based on the above facts on records, the present study has been under taken. With an objective of screening the antiulcer potentials 75% v/v aqueous ethanolic stem extracts of some three species of this genus, namely: V.punctatum, V.coriaceum and V.erubescens by aspirin plus pylorus ligation model in rats, using Ranitidine 50 mg/ kg b.w (p.o as the positive reference drug. From the findings of ulcer score, histo-pathological features and the status of biochemical parameters of gastric contents, it is concluded that extract of V.coriaceum at a dose level of 500 mg/kg.b.w possessed a significant antiulcer activity (p<0.01, p<0.001. However, the magnitude of antiulcer potential among the species was not far different. This study can be a referential tool for isolation of active constituents which are responsible for the above biological activity and to conduct an advanced scientific investigation on these species in that regard.

  9. Degradation of organic compounds and production of activated species in Dielectric Barrier Discharges and Glidarc reactors

    CERN Document Server

    Cormier, Jean Marie; Khacef, Ahmed

    2008-01-01

    Major sterilization mechanisms are related to atoms and radicals, charged parti-cles, excited molecules, ozone, and UV radiation. The ROS (Reactive Oxygen Species) are well known as evildoers. These species are easily created in ambient air and water and they live long enough to reach the cell and attack the organic matter. Test molecules conversion in dry and wet air is studied using Dielectric Barrier Discharge (DBD) and Gliding Arc Reactors (GAR). The effects of tem-perature and energy deposition into the media on the active species production and then on the organic compounds degradation are presented for two non thermal plasma reactors: DBD and GAR. Main production species investigated are OH, O3, NOx, CO and CxHyOz by-products. It is shown from experiment analysis that the reactive species production is quite different from one reactor to another. GAR and pulsed DBD are two chemical processing ways in which the temperature of heavy species in ionized gas is determinant. By reviewing the species producti...

  10. Effects of Earthworms Activities in Soil on Alkali -hydrolyzable Nitrogen and Total Nitrogen in the Soil of Copper Tailings Reclamation%蚯蚓活动对铜尾矿复垦地土壤氮的影响

    Institute of Scientific and Technical Information of China (English)

    张衡; 韩斐; 朱永恒

    2013-01-01

    This article conducts an experiment of culturing earthworms in the constant temperature (20 ℃) indoor for one month ,and studies the effects of earthworms activities on Alkali -hydrolyzable Nitrogen and Total Nitrogen in the Soil of Copper Tailings Reclamation .The experiment arranges four treatment methods in two vegetation soil of Arthraxon hispidus and Conyza canadensis :① no earthworm inoculation ,not adding straw (S);②only earthworms (E);③only add straw (O);④ earthworm inoculation ,adding straw (OE) ,the repeat 3 .The test results show :whether or not adding straw in mining area ,reclamation of earthworms (E ,OE) content can significantly improve the soil alkali hydrolysable nitrogen (p<0 .05) .Hispid Arthraxon earthworm (E) nitrogen content is 1 .10 times that of the control (S) ,Conyza canadens is earthworms (E) nitrogen content is 1 .06 times that of the control (S) .In the reclamation area of earthworms (E ,OE) could significantly increase the contents of soil total nitrogen (p<0 .05) . Hispid Arthraxon earthworm (E) total nitrogen content is 1 .5 times that of the control (S) ,Conyza canadensis earthworm (E) total nitrogen content is 1 .04 times that of the control (S);after inoculation of earthworms ,nitrogen mineralization rate of each treatment is positive ,and (p<0 .05) is significantly higher than that of the original soil samples ,earthworm activity in different vegetation effect differently on soil nitrogen .%在室内恒温(20℃)培养1个月后,研究了蚯蚓活动对铜尾矿复垦地土壤碱解氮和全氮的影响。实验分别设置草和小飞蓬2种植被土的4种处理:①不接种蚯蚓、不添加秸秆的对照(S );②仅接种蚯蚓(E );③仅添加秸秆(O);④接种蚯蚓、添加秸秆(OE),各重复3个。试验结果显示:无论是否添加秸秆,在矿区复垦地接种蚯蚓(E ,OE)可显著提高土壤中碱解氮的含量(p<0.05)。草接种蚯蚓(E)

  11. Simultaneous determination of nitrogen and phosphorus in cereals using 14 MeV Neutron Activation Analysis

    International Nuclear Information System (INIS)

    A method using 14 MeV neutron activation analysis was developed form non-destructive simultaneous determination of N and P in cereals. The samples were irradiated 5 min. after 0,5 min. decay time. The induced activities were measured using gamma spectrometry with Nal(Tl) well type detector. The accuracy, precision and detection limits obtained are discussed as well as the analytical results for different types of cereals. (Author) 10 refs., 8 tab., 1 fig

  12. IMPACT OF SALINITY AND SODICITY ON BIOMASS, TOTAL NITROGEN, NITRATE REDUCTASE ACTIVITY, LEAF AREA, AND CHLOROPHYLL CONTENTS IN MAIZE (ZEA MAYS L.

    Directory of Open Access Journals (Sweden)

    M. GUFRAN KHAN*, SHIMELIS*, G., ALEMU, H.* AND KEBENU, F**

    2014-11-01

    Full Text Available ABSTRACT: Salinity and sodicity are major constraint in increasing crop production at global level. Millions of the hectares of the land are too saline to produce economic yield.  In Ethiopia, 11 million ha of land is salt affected, about half of these soils are saline and remaining half are saline - sodic and sodic soil. As most of the arable land and quality water resources have already been exploited, the use of saline or urban/industrial waste water may be a viable alternative for further agro production. In view of such perspectives, an investigation was conducted to examine the effect of salinity (NaCl and sodicity (Na2CO3 on  biomass, total nitrogen, nitrate reductase activity, leaf area, and chlorophyll contents in Maize (Zea mays L. plants. The appropriate amount of NaCl and Na2CO3  was  dissolved in distilled water for appraisal of artificial  salinity and sodicity levels ( 0 , 4, 8,  and 12  and  mScm-1 in soil medium. Plants were also supplied with potassium (0 and 5mM KNO3 as remedial treatment. Maize plants were analyzed for germination, early growth, biomass, total nitrogen, Nitrate reductase activity, Leaf area, and chlorophyll contents as grown under different ECe levels of salinity and sodicity. The extent of salinity and sodicity effects was compared on the basis of different parameters. It was observed that plants showed substantial reduction in all parameters due to imposition of salinity and sodicity in root medium and it was more so due to sodicity. However, the use of additional potassium brought about an enhancement in these parameters.  It is suggested that plants may be raised in saline soil and saline water however; the extent of success depends upon salinity and sodicity levels, remedial treatments and plant species. The outcome of the present work may contribute towards viable utilization of saline soil and water for enhancing agro production of suitable crops, a desired goal to achieve food security.

  13. Solubilization of Waste Activated Sludge and Nitrogenous Compounds Transformation During Solubilization by Thermophilic Enzyme (S-TE) Process.

    Science.gov (United States)

    Yang, Qi; Luo, Kun; Li, Xiao-ming; Zhong, Yu; Chen, Hong-bo; Yang, Guo-jing; Shi, Yan-wei; Zeng, Guang-ming

    2015-06-01

    A representative thermophilic bacterial strain (AT06-1) capable of secreting protease was isolated from thermophilic aerobic digestion reactor, and 16S rRNA gene analysis indicated that it was Bacillus sp. The isolated strain was inoculated in waste activated sludge (WAS) to evaluate the performance of solubilization by thermophilic enzyme (S-TE) process under aerobic or microaerobic conditions at different temperatures (55-70 °C). Results showed that the inoculation of specific thermophilic strain significantly affected the volatile suspended solids (VSS) removal. At the optimal temperature of 65 °C, the maximum VSS removal of 43.6 % and highest SCOD of 4475 mg/L was achieved during microaerobic S-TE process. Compared to the noninoculation, more soluble protein was released during S-TE process due to the higher protease activity associated with the protein hydrolysis originated from cell lysis. The protease activity at aerobic and microaerobic S-TE process was respectively 1.73 and 1.88 times that of the noninoculation. Ammonia was the end nitrogenous compound of protein hydrolysis during S-TE process, which was stripped from the digestion system through continuous aeration.

  14. Nitrogen nutrition of the sedge Cyperus laevigatus-A candidate species for use in constructed wetlands in hot and dry regions

    DEFF Research Database (Denmark)

    Piwpuan, Narumol; Brix, Hans

    2011-01-01

    and tissue carbon and nitrogen contents of C. laevigatus were studied in hydroponically grown plants supplied with 0.5 mM nitrogen as NH4+or NO3- alone or in combination (NH4NO3). The relative growth rate (RGR) of NO3-–fed plants (RGR = 0.10 ± 0.02 g g-1 d-1) was significantly (P = 0.0002) lower than the RGR...

  15. Fluxes of methane and nitrogen oxides in various boreal mire ecosystems. Effects of land-use activities and environmental changes

    Energy Technology Data Exchange (ETDEWEB)

    Martikainen, P.J.; Nykaenen, H.; Regina, K. [National Public Health Inst., Kuopio (Finland). Lab. of Environmental Microbiology; Alm, J.; Silvola, J. [Joensuu Univ. (Finland). Dept. of Biology

    1996-12-31

    Atmospheric impact of peatlands is a sum of their gas fluxes. In contrast to carbon dioxide, peatlands are net sources for methane (CH{sub 4}). Methane is an end product in the anaerobic decomposition processes and it has greater capacity to absorb infrared radiation than carbon dioxide. Most of the data on the CH{sub 4} release from northern peatlands is from North America. The total amount of methane released from wetlands is calculated to be 110 Tg yr{sup -1} of which 34 percent (38 Tg yr{sup -1}) is estimated to be emitted from the northern peatlands. Peat with high content of nitrogen is a potential source for gaseous nitrogen oxides, i.e. nitrous oxide (N{sub 2}O) and nitric oxide (NO). However, the importance of peatlands in producing these trace gases is poorly known. Nitrous oxide and nitric oxide are important components in the atmospheric chemistry and N{sub 2}O also is an effective greenhouse gas. Land-use activities and environmental changes can affect the atmospheric impacts of peatlands by modifying their biogeochemistry. This article presents a short summary of the studies whose objectives were: (1) to measure fluxes of CH{sub 4} and N{sub 2}O on wide range of natural mires in Finland, (2) to study the short- and long-term changes in fluxes of CH{sub 4}, N{sub 2}O and NO on boreal peatlands after lowering their water table. Peatlands used for agriculture, forestry and peat mining were included in the studies. The results from mires drained for forestry may reflect the possible changes in the trace gas fluxes if water table will drop in the northern peatlands as a result of drier climate, (3) to study the effects of nitrogen load on the fluxes of CH{sub 4}, N{sub 2}O and NO, (4) to identify the microbiological processes important for the fluxes of N{sub 2}O, NO and CH{sub 4}, and to study the environmental factors regulating these microbial processes

  16. Wolbachia Do Not Induce Reactive Oxygen Species-Dependent Immune Pathway Activation in Aedes albopictus

    Directory of Open Access Journals (Sweden)

    Jennifer C. Molloy

    2015-08-01

    Full Text Available Aedes albopictus is a major vector of dengue (DENV and chikungunya (CHIKV viruses, causing millions of infections annually. It naturally carries, at high frequency, the intracellular inherited bacterial endosymbiont Wolbachia strains wAlbA and wAlbB; transinfection with the higher-density Wolbachia strain wMel from Drosophila melanogaster led to transmission blocking of both arboviruses. The hypothesis that reactive oxygen species (ROS-induced immune activation plays a role in arbovirus inhibition in this species was examined. In contrast to previous observations in Ae. aegypti, elevation of ROS levels was not observed in either cell lines or mosquito lines carrying the wild-type Wolbachia or higher-density Drosophila Wolbachia strains. There was also no upregulation of genes controlling innate immune pathways or with antioxidant/ROS-producing functions. These data suggest that ROS-mediated immune activation is not an important component of the viral transmission-blocking phenotype in this species.

  17. Activity of Brazilian and Bulgarian propolis against different species of Leishmania

    Directory of Open Access Journals (Sweden)

    Gérzia Maria de Carvalho Machado

    2007-02-01

    Full Text Available Extracts of propolis samples collected in Brazil and Bulgaria were assayed against four Leishmania species - Leishmania amazonensis, L. braziliensis, L. chagasi from the New World, and L. major from the Old World - associated to different clinical forms of leishmaniasis. The composition of the extracts has been previously characterized by high temperature high resolution gas chromatography coupled to mass spectrometry. Considering the chemical differences among the extracts and the behavior of the parasites, it was observed significant differences in the leishmanicidal activities with IC50/1 day values in the range of 2.8 to 229.3 µg/ml . An overall analysis showed that for all the species evaluated, Bulgarian extracts were more active than the ethanol Brazilian extract. As the assayed propolis extracts have their chemical composition determined it merits further investigation the effect of individual components or their combinations on each Leishmania species.

  18. Seasonal activity patterns and diet divergence of three sympatric Afrotropical tortoise species (genus Kinixys)

    OpenAIRE

    Luiselli, Luca

    2003-01-01

    Three species of hinge-back tortoises ( (Kinixys belliana nogueyi, Kinixys erosa, Kinixys homeana) are found in simpatry in the rainforests of the Niger Delta, southern Nigeria (west Africa). The seasonal activity patterns and food habits of these tortoises are studied in the present paper. K. erosa and K. homeana have similar activity patterns, with peaks occurring during the wet season. Kinixys belliana was found only during the wet months. There was no evidence of any specific effect of hu...

  19. Antimicrobial activity of Brazilian copaiba oils obtained from different species of the Copaifera genus

    OpenAIRE

    Adriana Oliveira dos Santos; Tânia Ueda-Nakamura; Benedito Prado Dias Filho; Valdir F. Veiga Junior; Angelo C. Pinto; Celso Vataru Nakamura

    2008-01-01

    The antimicrobial activity of copaiba oils was tested against Gram-positive and Gram-negative bacteria, yeast, and dermatophytes. Oils obtained from Copaifera martii, Copaifera officinalis, and Copaifera reticulata (collected in the state of Acre) were active against Gram-positive species (Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, Bacillus subtilis, and Enterococcus faecalis) with minimum inhibitory concentrations ranging from 31.3-62.5 µg/ml. The oil...

  20. Characterization of Serum Phospholipase A2 Activity in Three Diverse Species of West African Crocodiles

    OpenAIRE

    Mark Merchant; Kate Juneau; Jared Gemillion; Rodolfo Falconi; Aaron Doucet; Shirley, Matthew H.

    2011-01-01

    Secretory phospholipase A2, an enzyme that exhibits substantial immunological activity, was measured in the serum of three species of diverse West African crocodiles. Incubation of different volumes of crocodile serum with bacteria labeled with a fluorescent fatty acid in the sn-2 position of membrane lipids resulted in a volume-dependent liberation of fluorescent probe. Serum from the Nile crocodile (Crocodylus niloticus) exhibited slightly higher activity than that of the slender-snouted cr...

  1. Seasonal activity patterns and diet divergence of three sympatric Afrotropical tortoise species (genus Kinixys)

    NARCIS (Netherlands)

    Luiselli, Luca

    2003-01-01

    Three species of hinge-back tortoises ( (Kinixys belliana nogueyi, Kinixys erosa, Kinixys homeana) are found in simpatry in the rainforests of the Niger Delta, southern Nigeria (west Africa). The seasonal activity patterns and food habits of these tortoises are studied in the present paper. K. erosa

  2. Comparative in vitro activities of twelve antimicrobial agents against Campylobacter species.

    OpenAIRE

    Fliegelman, R M; Petrak, R M; Goodman, L. J.; Segreti, J; Trenholme, G M; Kaplan, R L

    1985-01-01

    The in vitro susceptibility of 27 Campylobacter jejuni, 31 Campylobacter coli, and 30 Campylobacter fetus subsp. fetus strains to 12 antimicrobial agents was determined. Ciprofloxacin, a new quinoline derivative, was the most active agent tested. Antimicrobial susceptibility differed among the three species tested.

  3. Cytotoxic activities of ethyl acetate extract and a metabolite from a Monocillium species.

    Science.gov (United States)

    Khondkar, Proma; Rahman, M Mukhlesur; Islam, Anwarul

    2005-09-01

    The ethyl acetate soluble fraction of a cultural broth of a Monocillium species afforded the isolation of 5-hydroxymethylfurfural. Both the extract and 5-hydroxymethylfurfural showed significant cytotoxic activities in a brine shrimp bioassay and the LC(50) values were found to be 14.96 microg/mL and 23.71 microg/mL, respectively. PMID:16220580

  4. Antioxidant activity screening of extracts from Sideritis species (Labiatae) grown in Bulgaria

    NARCIS (Netherlands)

    Koleva, I.; Linssen, J.P.H.; Beek, van T.A.; Evstatieva, L.N.; Kortenska, V.; Handjieva, N.

    2003-01-01

    Plant samples from several species and populations of the genus Sideritis (Labiatae) grown in Bulgaria (S scardica, S syriaca and S montana) were extracted with different solvents. Their antioxidant activities were determined by the -carotene bleaching test (BCBT), 2,2-diphenyl-1-picrylhydrazyl (DPP

  5. Adsorption/oxidation of sulfur-containing gases on nitrogen-doped activated carbon

    OpenAIRE

    Liu Qiang; Ke Ming; Yu Pei; Hu Hai Qiang; Yan Xi Ming

    2016-01-01

    Coconut shell-based activated carbon (CAC) was used for the removal of methyl mercaptan (MM). CAC was modified by urea impregnation and calcined at 450°C and 950°C. The desulfurization activity was determined in a fixed bed reactor under room temperature. The results showed that the methyl mercaptan adsorption/oxidation capacity of modified carbon caicined at 950°C is more than 3 times the capacity of original samples. On the other hand, the modified carbon caicined at 950°C also has a high c...

  6. Modeling forest development after fire disturbance: Climate, soil organic layer, and nitrogen jointly affect forest canopy species and long-term ecosystem carbon accumulation in the North American boreal forest

    Science.gov (United States)

    Trugman, A. T.; Fenton, N.; Bergeron, Y.; Xu, X.; Welp, L.; Medvigy, D.

    2015-12-01

    Soil organic layer dynamics strongly affect boreal forest development after fire. Field studies show that soil organic layer thickness exerts a species-specific control on propagule establishment in the North American boreal forest. On organic soils thicker than a few centimeters, all propagules are less able to recruit, but broadleaf trees recruit less effectively than needleleaf trees. In turn, forest growth controls organic layer accumulation through modulating litter input and litter quality. These dynamics have not been fully incorporated into models, but may be essential for accurate projections of ecosystem carbon storage. Here, we develop a data-constrained model for understanding boreal forest development after fire. We update the ED2 model to include new aspen and black spruce species-types, species-specific propagule survivorship dependent on soil organic layer depth, species-specific litter decay rates, dynamically accumulating moss and soil organic layers, and nitrogen fixation by cyanobacteria associated with moss. The model is validated against diverse observations ranging from monthly to centennial timescales and spanning a climate gradient in Alaska, central Canada, and Quebec. We then quantify differences in forest development that result from changes in organic layer accumulation, temperature, and nitrogen. We find that (1) the model accurately reproduces a range of observations throughout the North American boreal forest; (2) the presence of a thick organic layer results in decreased decomposition and decreased aboveground productivity, effects that can increase or decrease ecosystem carbon uptake depending on location-specific attributes; (3) with a mean warming of 4°C, some forests switch from undergoing succession to needleleaf forests to recruiting multiple cohorts of broadleaf trees, decreasing ecosystem accumulation by ~30% after 300 years; (4) the availability of nitrogen regulates successional dynamics such than broadleaf species are

  7. An Active Sensor Nitrogen Application Algorithm for Corn Using a Chlorophyll Meter Based Sufficiency Index Concept

    Science.gov (United States)

    Traditional N fertilizer management schemes for U.S. corn production systems have resulted in low N use efficiency, reduced water quality, and considerable public debate regarding N use in crop production. We have built a prototype high clearance N applicator configured with active sensors, controll...

  8. Improving in-season nitrogen recommendations for maize using an active sensor

    Science.gov (United States)

    An active crop canopy reflectance sensor could be used to increase N-use efficiency in corn (Zea mays L.), if temporal and spatial variability in soil N availability and plant demand are adequately accounted for with an in-season N application. Our objective was to evaluate the success of using an a...

  9. STUDIES ON THE CATALYTIC REACTION OF NITROGEN OXIDE ON METAL MODIFIED ACTIVATED CARBON FIBERS

    Institute of Scientific and Technical Information of China (English)

    FU Ruowen; DU Xiuying; LIN Yuansheng; XU Hao; HU Yiongjun

    2003-01-01

    The catalytic reaction of NO with CO and decomposition of NO over metal modified ACFs were investigated and compared with other carriers supported catalysts. It is demonstrated that Pd/ACF and Pd/Cu/ACF have high catalytic activity for the reaction of NO/CO, while Pt/ACF.Pt/Cu/ACF and Co/Cu/ACF have very Iow catalytic activity in similar circumstance. Pd-modified ACF possesses high catalytic decomposition of NO at 300 ℃. Pd/CB and Pd/GAC present good catalytic decomposition ability for NO only at low flowrate. Pd/G, Pd/ZMS and Pd/A however, do not show any catalytic activity for NO decomposition even at 400 ℃. Catalytic temperature, NO flowrate and loading of metal components affect the decomposition rate of NO. The coexistence of Cu with Pd on Cu/Pd/ACF leads to crystalline of palladium to more unperfected so as to that increase the catalytic activity.

  10. In vitro antibacterial activity of three medicinal plants-Boswellia (Luban) species

    Institute of Scientific and Technical Information of China (English)

    Hasson SS; Al-Balushi MS; Sallam TA; Idris MA; Habbal O; Al-Jabri AA

    2011-01-01

    Objective:To study in vitro antibacterial and antifungal activity of hot water and methanolic extracts of the three medicinal plants-Boswellia (Luban) species. Methods:Three selected plants were collected from different localities of Soqotra (Republic of Yemen), Dohfar (Sultanate of Oman) and Republic of Somalia. The plants were dried and extracted with two different solvents (methanol and hot water) to yield six crude extracts. The obtained extracts were tested for their antibacterial activity against eleven different bacterial strains and two fungi using the standard well-diffusion and micro-dilution methods. The following microorganisms were used:methicillin-resistant Staphylococcus aureus (ATCC 6538), muti-drug resistant Pseudomonas aeruginosa (ATCC 27853), enterohemorrhagic Escherichia coli (0157 EHEC), Salmonella typhi, Proteus vulgaris, Klebsiella pneumoniae, Bacillus subtilus (ATCC 6059, reference strain), Streptococcus pneumoniae, Klebsella pneumonia, MRSA, Corynebacterium, Corynebacterium diphtheriae and two fungus:Candida maltosa and Candida albicans. Results: The different extracts possessed different inhibitory activity against different types of bacterial species. The patterns of inhibition varied with the plant extract, the solvent used for extraction and the organisms tested. The antimicrobial activity exhibited by the methanolic extracts of Boswellia sacra from the Suqotra and Dhofar regions was greater than that of Boswellia frereana collected from Somalia. The methanolic extract of the oleo-gum-resin showed higher efficacy to inhibit all the tested bacterial strains than the methanolic extract of frankincense-resin. The Boswellia frereana collected from Somalia showed lower activity compared with the two other Boswellia species. The plant extracts showed bacteriostatic activity at lower concentrations and bactericidal activity at higher concentrations. Neither water nor methanolic extracts showed any activity against the fungi Candida maltosa and

  11. In vitro Antioxidant Activity between Bioactive Compounds from Nine Species of Passiflora

    Directory of Open Access Journals (Sweden)

    DAV Montero

    2015-06-01

    Full Text Available Main bioactive substances identified from the genus Passiflora include polyphenols, flavonoids, carotenoids, anthocyanins and other natural antioxidants that are critical factors for maintaining optimum health. Polyphenols mainly C-glycosides are present in well studied species such as P. edulis, P. incarnata and P. alata. However, most Passiflora species remains little explored and it’s for this reason that we address our work at the comparison between species. Three experiments with completely randomized designs were performed in order to compare the total amount of flavonoids, phenols and in vitro free radical DPPH scavenger activity (%DPPH of nine species of Passiflora (P. edulis, P. alata, P. incarnata, P. ligularis, P. tripartite, P. coccinea, P. gardneri, P. laurifólia and P. mucronata. Non parametric Kruskal-Wallis and Friedman tests (for flavonoids, parametric analyses of variances (Anova and the last significant differences (LSD tests (for phenols and free radical scavenger activity were performed to compare the studied species and then a correlation analysis was carried out to assess the interaction between the variables using RStudio statistical software. Results showed significant differences between the studied passionflowers for the total amount of flavonoids (p=4.4e-5, total amount of phenols (p=2.2e-16 and scavenger activity of the free radical DPPH (p=2.2e-16. Also, we found a positive correlation between %DPPH scavenging activity and the total content of polyphenols (Pearson’s coefficient=0.706 and a negative one between flavonoid (Pearson’s coefficient=-0.485. The results suggest that in passionflower leaf samples the scavenging activity of the free radical DPPH is more related with polyphenols rather than flavonoids.

  12. Response of oxidative enzyme activities to nitrogen deposition affects soil concentrations of dissolved organic carbon

    Science.gov (United States)

    Waldrop, M.P.; Zak, D.R.

    2006-01-01

    Recent evidence suggests that atmospheric nitrate (NO3- ) deposition can alter soil carbon (C) storage by directly affecting the activity of lignin-degrading soil fungi. In a laboratory experiment, we studied the direct influence of increasing soil NO 3- concentration on microbial C cycling in three different ecosystems: black oak-white oak (BOWO), sugar maple-red oak (SMRO), and sugar maple-basswood (SMBW). These ecosystems span a broad range of litter biochemistry and recalcitrance; the BOWO ecosystem contains the highest litter lignin content, SMRO had intermediate lignin content, and SMBW leaf litter has the lowest lignin content. We hypothesized that increasing soil solution NO 3- would reduce lignolytic activity in the BOWO ecosystem, due to a high abundance of white-rot fungi and lignin-rich leaf litter. Due to the low lignin content of litter in the SMBW, we further reasoned that the NO3- repression of lignolytic activity would be less dramatic due to a lower relative abundance of white-rot basidiomycetes; the response in the SMRO ecosystem should be intermediate. We increased soil solution NO3- concentrations in a 73-day laboratory incubation and measured microbial respiration and soil solution dissolved organic carbon (DOC) and phenolics concentrations. At the end of the incubation, we measured the activity of ??-glucosidase, N-acetyl-glucosaminidase, phenol oxidase, and peroxidase, which are extracellular enzymes involved with cellulose and lignin degradation. We quantified the fungal biomass, and we also used fungal ribosomal intergenic spacer analysis (RISA) to gain insight into fungal community composition. In the BOWO ecosystem, increasing NO 3- significantly decreased oxidative enzyme activities (-30% to -54%) and increased DOC (+32% upper limit) and phenolic (+77% upper limit) concentrations. In the SMRO ecosystem, we observed a significant decrease in phenol oxidase activity (-73% lower limit) and an increase in soluble phenolic concentrations

  13. Screening of radical scavenging activity and polyphenol content of Bulgarian plant species

    Directory of Open Access Journals (Sweden)

    Milena Nikolova

    2011-01-01

    Full Text Available Background: Discovery of new plant species with antioxidant properties is a priority of many research teams. Most of the species included in this study are unstudied for antioxidant properties, but they are taxonomically related to reference plants with well-documented antioxidant activity. Materials and Methods: Free radical scavenging activity of plant extracts was evaluated using a 1,1-diphenyl-2-picrylhydrazyl (DPPH assay. An aluminum chloride colorimetric method was used for flavonoid determination. The amount of phenolic compounds in the extracts was estimated by using the Folin-Ciocalteu reagent. Results: As a result of screening, it was found that the significant antioxidant properties possess several unstudied until now plant species (Veronica bellidioides L., V. kellereri Deg. et Urm, V. vindobonensis (M. Fisher M. Fisher, V. beccabunga L., V. rhodopaea L., V. austriaca (Velen. Degen., Clinopodium vulgare L., Stachys recta L., Clematis vitalba L., and Xeranthemum annum L.. The antioxidant potential of the new species is comparable to that of reference medicinal plants. Conclusions: The existing data presented here provide new information for antioxidant potential of plant species that have not been traditionally used as medicinal plants.

  14. Antibiofilm activity of carboxymethyl chitosan on the biofilms of non-Candida albicans Candida species.

    Science.gov (United States)

    Tan, Yulong; Leonhard, Matthias; Moser, Doris; Schneider-Stickler, Berit

    2016-09-20

    Although most cases of candidiasis have been attributed to Candida albicans, non-C. albicans Candida species have been isolated in increasing numbers in patients. In this study, we determined the inhibition of carboxymethyl chitosan (CM-chitosan) on single and mixed species biofilm of non-albicans Candida species, including Candida tropicalis, Candida parapsilosis, Candida krusei and Candida glabrata. Biofilm by all tested species in microtiter plates were inhibited nearly 70%. CM-chitosan inhibited mixed species biofilm in microtiter plates and also on medical materials surfaces. To investigate the mechanism, the effect of CM-chitosan on cell viability and biofilm growth was employed. CM-chitosan inhibited Candida planktonic growth as well as adhesion. Further biofilm formation was inhibited with CM-chitosan added at 90min, 12h or 24h after biofilm initiation. CM-chitosan was not only able to inhibit the metabolic activity of Candida cells, but was also active upon the establishment and the development of biofilms.

  15. Antibiofilm activity of carboxymethyl chitosan on the biofilms of non-Candida albicans Candida species.

    Science.gov (United States)

    Tan, Yulong; Leonhard, Matthias; Moser, Doris; Schneider-Stickler, Berit

    2016-09-20

    Although most cases of candidiasis have been attributed to Candida albicans, non-C. albicans Candida species have been isolated in increasing numbers in patients. In this study, we determined the inhibition of carboxymethyl chitosan (CM-chitosan) on single and mixed species biofilm of non-albicans Candida species, including Candida tropicalis, Candida parapsilosis, Candida krusei and Candida glabrata. Biofilm by all tested species in microtiter plates were inhibited nearly 70%. CM-chitosan inhibited mixed species biofilm in microtiter plates and also on medical materials surfaces. To investigate the mechanism, the effect of CM-chitosan on cell viability and biofilm growth was employed. CM-chitosan inhibited Candida planktonic growth as well as adhesion. Further biofilm formation was inhibited with CM-chitosan added at 90min, 12h or 24h after biofilm initiation. CM-chitosan was not only able to inhibit the metabolic activity of Candida cells, but was also active upon the establishment and the development of biofilms. PMID:27261732

  16. Nitrogen nutrition of Canna indica: Effects of ammonium versus nitrate on growth, biomass allocation, photosynthesis, nitrate reductase activity and N uptake rates

    DEFF Research Database (Denmark)

    Konnerup, Dennis; Brix, Hans

    2010-01-01

    The effects of inorganic nitrogen (N) source (NH4+, NO3- or both) on growth, biomass allocation, photosynthesis, N uptake rate, nitrate reductase activity and mineral composition of Canna indica were studied in hydroponic culture. The relative growth rates (0.05-0.06 g g-1 d-1), biomass allocation...

  17. Effect of Cl— on Behavior of Fertilizer Nitrogen, Number of Microorganisms and Enzyme Activities in Soils

    Institute of Scientific and Technical Information of China (English)

    SHIWEI-YONG; CHENGMEI-ZI; 等

    1994-01-01

    Pot experiments were conducted to study the effect of Cl- on transformation of fertilizer N,number of microorganisms and enzyme activities in soils.It is indicated that Cl- did not show significant influence on total number of bacteria,actinomyces and fungi,but significantly reduced the number of nitrosolbacteria, which led to decrease of NO3- content in the soil.Application of Cl- to soil could significantly enhance the adtivities of phosphatase and urease in the coastal saline soil and orthic aquisols,In hilly red soil,however,the application of Cl-1 at the rate of 500-1000mg Cl- kg-1 soil significantly decreased the activity of the two enzymes mentioned above.

  18. Preparation, Characterization and Visible Light Photocatalytic Activity of Nitrogen-doped TiO2

    Institute of Scientific and Technical Information of China (English)

    WANG Zhengpeng; GONG Wenqi; HONG Xiaoting; CAI Weimin; JIANG Juhui; ZHOU Baoxue

    2006-01-01

    The N- doped TiO2 polycrystalline powder was synthesized through calcining the hydrolysis product of tetra-butyl titanate with ammonia. The photocatalytic activity of N-doped TiO2 powder with anatase phase calcined at 400 ℃ was 2.7 times higher than that of Degussa P25 for phenol decomposition under visible light. All samples had mesoporous structures. X- ray photoelectron spectroscopy corfirmed that a trace amount of N atoms remained in the anatase polycrystalline TiO2 powder when calcined at 400 ℃ as substitutional atoms at the oxygen sites. UV-Vis and EPR analyses indicated that oxygen vacancy states were created during the course of N-doped TiO2 powder formation. It is considered that substitutional N atoms, oxygen vacancy states, large BET surface areas and mesoporous structure are important factors for the N-doped photocatalyst to present a high vis-activity.

  19. Antioxidant and Antibacterial Activities of Five Verbenaceae Species from Burkina Faso

    Directory of Open Access Journals (Sweden)

    M.J. Bangou

    2012-11-01

    Full Text Available The present study aimed to evaluate the antioxidant and the antibacterial activities of methanol extracts from five species from Verbenaceae family and to quantify their polyphenols. Two methods i.e., FRAP and DPPH were used to estimate the total antioxidant capacity of the plants materials. Antibacterial activity was measured on serotyped bacteria (4 and pathogenic bacteria (13 using the solid agar dishes diffusion method. Polyphenolic quantification was measured using Folin-Ciocalteu, ammonium citrate iron and AlCl3 reagents, respectively. Fe (III to iron (II reducing activity show to be relate to tannins content and the radical scavenging activity by total phenolic and total flavonols. As a whole Duranta erecta L. gave a better antioxidant activity (FRAP: 15.03 mmol EAA/g and IC50: 7.88 mmol EAA/g. The best antimicrobial activity was obtained by Duranta erecta L. (22.33 mm at a concentration of 25 μg/mL. This result was obtained on Gram-positive bacteria such as Staphylococcus épidermidis. The results obtained in this study showed an interesting antioxidant activity of Duranta erecta L. This plant also presented the best antibacterial activity particularly on Staphylococcus épidermidis, among the five species of Verbenaceae family. Our findings could partially justify the traditional uses of these plants as indicated in the literature.

  20. Brassica spp cover crop affects soil microbial activity, carbon and nitrogen nutrient dynamics

    OpenAIRE

    Marinari, S.; Papp, R.; Marabottini, R.; Moscatelli, M. C.

    2015-01-01

    A general positive effect of Brassica on soil microbial biomass and its activity was observed at all European sites in no tilled soil at both sampling date. Conversely, Brassica under tillage may produce a negative effect on biochemical properties after CC suppression. The effect of Brassica on C and N dynamics differed among the european sites when soil was tilled. These preliminary results establish the bases for the evaluation of the interaction between the pedoclimatic conditions and Bras...

  1. Nitrogen-doped TiO2 nanotube array films with enhanced photocatalytic activity under various light sources

    International Nuclear Information System (INIS)

    Highly ordered nitrogen-doped titanium dioxide (N-doped TiO2) nanotube array films with enhanced photocatalytic activity were fabricated by electrochemical anodization, followed by a wet immersion and annealing post-treatment. The morphology, structure and compostition of the N-doped TiO2 nanotube array films were investigated by FESEM, XPS, UV-vis and XRD. The effect of annealing temperature on the morphology, structures, photoelectrochemical property and photo-absorption of the N-doped TiO2 nanotube array films was investigated. Liquid chromatography and mass spectrometry were applied to the analysis of the intermediates coming from the photocatalytic degradation of MO. The experimental results showed that there were four primary intermediates existing in the photocatalytic reaction. Compared with the pure TiO2 nanotube array film, the N-doped TiO2 nanotubes exhibited higher photocatalytic activity in degradating methyl orange into non-toxic inorganic products under both UV and simulated sunlight irradiation.

  2. [Chemical structure and immunobiological activities of peptidoglycan isolated from Capnocytophaga species].

    Science.gov (United States)

    Hanagata, T

    1990-12-01

    The chemical structure and immunobiological activities of the cell wall peptidoglycan isolated from Capnocytophaga species was investigated. Peptidoglycan was isolated from Capnocytophaga species strain SE2-2 by boiling in 4% sodium dodecyl sulfate and by digestion with pronase, trypsin and alpha-amylase. Analysis of amino acids and amino sugars of the peptidoglycan revealed that glucosamine, muramic acid, D-glutamic acid, alanine, and diaminopimelic acid (A2pm) were the principal components. Serine and glycine were not found. Dinitrophenylation method revealed that about half of A2pm residue had a free amino group, and analysis by hydrazinolysis showed that a small part of alanine and A2pm located at the C-terminal. The above results indicate that one of the amino groups of A2pm residue at one strand of the stem peptide subunit cross-linked to the carboxyl group of alanine of the neighboring strand. It was thus revealed that the peptidoglycan of Capnocytophaga species belonged to the Al gamma type of the classification by Schleifer and Kandler. Peptidoglycan isolated from Capnocytophaga species strain SE2-2 was found to be definitely adjuvant-active in induction of delayed type hypersensitivity against ovalbumin when administered to guinea pigs as water-in-oil emulsion and in stimulation of increase serum antibody levels. Regarding mitogenicity on splenocytes of BALB/c and BALB/c nu/nu mice, peptidoglycan from Capnocytophaga species was markedly enhanced the uptake [3H] thymidine in dose of 10 micrograms/10(5) cells, however thymocytes were not reactive. Stimulation effects on peritoneal macrophages from a guinea pig to incorporation of 14C-glucosamin was exhibited by addition of 100 micrograms of this peptidoglycan. These findings indicate that peptidoglycan of Capnocytophaga species might eventually be responsible for destruction of periodontal tissue by host mediated activities.

  3. Antioxidant activity and total phenolic content of 24 Lamiaceae species growing in Iran.

    Science.gov (United States)

    Firuzi, Omidreza; Javidnia, Katayoun; Gholami, Maryam; Soltani, Mohammad; Miri, Ramin

    2010-02-01

    The antioxidant activities of the methanolic extracts of 9 Salvia species and 15 other Lamiaceae plants growing in Iran were evaluated using ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays. FRAP values ranged form 8.5 to 79.0 microM quercetin equivalents/g dry weight, and IC50 values in the DPPH assay from 115.7 to 1350.2 microg dry weight/mL. Salvia species showed the highest antioxidant activities. S. santolinifolia, S. eremophila and S. palestina, which have not been studied before, were the most active plants. These were more active than the previously studied species from this family, such as S. multicaulis and Marrubium vulgare. S. hydrangea and Gontscharovia popovii also showed high antioxidant activities. FRAP and DPPH assay results showed good correlations with the total phenolic contents of the plants, measured by the Folin-Ciocalteau assay (r2 = 0.925 and 0.799, respectively, p < 0.0001). In conclusion, our study shows that some Lamiaceae plants growing in Iran represent good potential sources of natural antioxidants useful for either prevention or treatment of oxidative stress-related diseases. PMID:20334140

  4. The relationship between total cholinesterase activity and mortality in four butterfly species.

    Science.gov (United States)

    Bargar, Timothy A

    2012-09-01

    The relationship between total cholinesterase activity (TChE) and mortality in four butterfly species (great southern white [Ascia monuste], common buckeye [Junonia coenia], painted lady [Vanessa cardui], and julia butterflies [Dryas julia]) was investigated. Acute contact toxicity studies were conducted to evaluate the response (median lethal dose [LD50] and TChE) of the four species following exposure to the organophosphate insecticide naled. The LD50 for these butterflies ranged from 2.3 to 7.6 µg/g. The average level of TChE inhibition associated with significant mortality ranged from 26 to 67%, depending on the species. The lower bounds of normal TChE activity (2 standard deviations less than the average TChE for reference butterflies) ranged from 8.4 to 12.3 µM/min/g. As a percentage of the average reference TChE activity for the respective species, the lower bounds were similar to the inhibition levels associated with significant mortality, indicating there was little difference between the dose resulting in significant TChE inhibition and that resulting in mortality. PMID:22740147

  5. The relationship between total cholinesterase activity and mortality in four butterfly species

    Science.gov (United States)

    Bargar, Timothy A.

    2012-01-01

    The relationship between total cholinesterase activity (TChE) and mortality in four butterfly species (great southern white [Ascia monuste], common buckeye [Junonia coenia], painted lady [Vanessa cardui], and julia butterflies [Dryas julia]) was investigated. Acute contact toxicity studies were conducted to evaluate the response (median lethal dose [LD50] and TChE) of the four species following exposure to the organophosphate insecticide naled. The LD50 for these butterflies ranged from 2.3 to 7.6 μg/g. The average level of TChE inhibition associated with significant mortality ranged from 26 to 67%, depending on the species. The lower bounds of normal TChE activity (2 standard deviations less than the average TChE for reference butterflies) ranged from 8.4 to 12.3 μM/min/g. As a percentage of the average reference TChE activity for the respective species, the lower bounds were similar to the inhibition levels associated with significant mortality, indicating there was little difference between the dose resulting in significant TChE inhibition and that resulting in mortality.

  6. Interactive Effects of Nitrogen and Climate Change on Biodiversity

    Science.gov (United States)

    Porter, E. M.; Bowman, W. D.; Clark, C. M.; Compton, J. E.; Pardo, L. H.; Soong, J.

    2011-12-01

    Biodiversity has been described as the diversity of life on earth within species, between species and in ecosystems. Biodiversity contributes to regulating ecosystem services like climate, flood, disease, and water quality regulation. Biodiversity also supports and sustains ecosystem services that provide material goods like food, fiber, fuel, timber and water, and to non-material benefits like educational, recreational, spiritual, and aesthetic ecosystem services. The Millennium Ecosystem Assessment estimated that the rate of biodiversity loss due to human activity in the last 50 years has been more rapid than at any other time in human history, and that many of the drivers of biodiversity loss are increasing. The strongest drivers of biodiversity loss include habitat loss, overexploitation, invasive species, climate change, and pollution, including pollution from reactive nitrogen. Of these stressors, climate change and reactive nitrogen from anthropogenic activities are causing some of the most rapid changes. Climate change is causing warming trends that result in consistent patterns of poleward and elevational range shifts of flora and fauna, causing changes in biodiversity. Warming has also resulted in changes in phenology, particularly the earlier onset of spring events, migration, and lengthening of the growing season, disrupting predator-prey and plant-pollinator interactions. In addition to warming, elevated carbon dioxide by itself can affect biodiversity by influencing plant growth, soil water, tissue stoichiometry, and trophic interactions. Nitrogen enrichment also impacts ecosystems and biodiversity in a variety of ways. Nitrogen enhances plant growth, but has been shown to favor invasive, fast-growing species over native species adapted to low nitrogen conditions. Although there have been a limited number of empirical studies on climate change and nitrogen interactions, inferences can be drawn from observed responses to each stressor by itself. For

  7. Diversity of Secondary Metabolites from Marine Bacillus Species: Chemistry and Biological Activity

    Directory of Open Access Journals (Sweden)

    Hee Jae Shin

    2013-08-01

    Full Text Available Marine Bacillus species produce versatile secondary metabolites including lipopeptides, polypeptides, macrolactones, fatty acids, polyketides, and isocoumarins. These structurally diverse compounds exhibit a wide range of biological activities, such as antimicrobial, anticancer, and antialgal activities. Some marine Bacillus strains can detoxify heavy metals through reduction processes and have the ability to produce carotenoids. The present article reviews the chemistry and biological activities of secondary metabolites from marine isolates. Side by side, the potential for application of these novel natural products from marine Bacillus strains as drugs, pesticides, carotenoids, and tools for the bioremediation of heavy metal toxicity are also discussed.

  8. 2,4,6-Trichlorophenol mediated increases in extracellular peroxidase activity in three species of Lemnaceae.

    Science.gov (United States)

    Biswas, Dilip K; Scannell, Gillian; Akhmetov, Nurlan; Fitzpatrick, Dara; Jansen, Marcel A K

    2010-11-01

    Chlorinated phenols, or chlorophenols, are persistent priority pollutants that are widespread in the environment. Class III peroxidases are well-characterised plant enzymes that can catalyse the oxidative dechlorination of chlorophenols. Expression of these enzymes by plants is commonly associated with plant stress, therefore limiting scope for phytoremediation. In this study, we have quantitatively compared peroxidase activity and phytotoxicity as a function of 2,4,6-trichlorophenol (TCP) concentration in three species of Lemnaceae; Lemna minor, Lemna gibba and Landoltia punctata. Effects of TCP on the growth rates of the three species differed considerably with L. punctata being the most tolerant species. TCP also affected photosynthetic parameters, causing a decrease in open photosystem II reaction centres (qP) and, in L. punctata only, a decrease in non-photochemical quenching (qN). In parallel, TCP exposure resulted in increased peroxidase activity in all three species. Peroxidase activity in L. minor and L. gibba displayed an inverse relationship with biomass accumulation, i.e. the more growth reduction the more peroxidase activity. In contrast, induction of peroxidase activity in L. punctata was bi-phasic, with a TCP-induced activity peak at concentrations that had no major effect on growth, and further induction under phytotoxic concentrations. The mechanism by which L. punctata recognises and responds to low concentrations of an anthropogenic compound, in the absence of wide-ranging stress, remains enigmatic. However, we conclude that this "window" of peroxidase production in the absence of major growth inhibition offers potential for the development of sustainable, peroxidise-mediated phytoremediation systems. PMID:20810175

  9. Metal-free catalysis of persulfate activation and organic-pollutant degradation by nitrogen-doped graphene and aminated graphene.

    Science.gov (United States)

    Chen, Hao; Carroll, Kenneth C

    2016-08-01

    We evaluated three types of functionalized, graphene-based materials for activating persulfate (PS) and removing (i.e., sorption and oxidation) sulfamethoxazole (SMX) as a model emerging contaminant. Although advanced oxidative water treatment requires PS activation, activation requires energy or chemical inputs, and toxic substances are contained in many catalysts. Graphene-based materials were examined herein as an alternative to metal-based catalysts. Results show that nitrogen-doped graphene (N-GP) and aminated graphene (NH2-GP) can effectively activate PS. Overall, PS activation by graphene oxide was not observed in this study. N-GP (50 mg L(-1)) can rapidly activate PS (1 mM) to remove >99.9% SMX within 3 h, and NH2-GP (50 mg L(-1)) activated PS (1 mM) can also remove 50% SMX within 10 h. SMX sorption and total removal was greater for N-GP, which suggests oxidation was enhanced by increasing proximity to PS activation sites. Increasing pH enhanced the N-GP catalytic ability, and >99.9% SMX removal time decreased from 3 h to 1 h when pH increased from 3 to 9. However, the PS catalytic ability was inhibited at pH 9 for NH2-GP. Increases in ionic strength (100 mM NaCl or Na2SO4) and addition of radical scavengers (500 mM ethanol) both had negligible impacts on SMX removal. With bicarbonate addition (100 mM), while the catalytic ability of N-GP remained unaltered, NH2-GP catalytic ability was inhibited completely. Humic acid (250 mg L(-1)) was partially effective in inhibiting SMX removal in both N-GP and NH2-GP systems. These results have implications for elucidating oxidant catalysis mechanisms, and they quantify the ability of functionalization of graphene with hetero-atom doping to effectively catalyze PS for water treatment of organic pollutants including emerging contaminants. PMID:27179328

  10. Updated activated sludge model number 1 parameter values for improved prediction of nitrogen removal in activated sludge processes: validation at 13 full-scale plants.

    Science.gov (United States)

    Choubert, Jean-Marc; Stricker, Anne-Emmanuelle; Marquot, Aurélien; Racault, Yvan; Gillot, Sylvie; Héduit, Alain

    2009-01-01

    The Activated Sludge Model number 1 (ASM1) is the main model used in simulation projects focusing on nitrogen removal. Recent laboratory-scale studies have found that the default values given 20 years ago for the decay rate of nitrifiers and for the heterotrophic biomass yield in anoxic conditions were inadequate. To verify the relevance of the revised parameter values at full scale, a series of simulations were carried out with ASM1 using the original and updated set of parameters at 20 degrees C and 10 degrees C. The simulation results were compared with data collected at 13 full-scale nitrifying-denitrifying municipal treatment plants. This work shows that simulations using the original ASM1 default parameters tend to overpredict the nitrification rate and underpredict the denitrification rate. The updated set of parameters allows more realistic predictions over a wide range of operating conditions. PMID:19860142

  11. Antioxidant Activities and Phytochemical Study of Leaf Extracts from 18 Indigenous Tree Species in Taiwan

    Directory of Open Access Journals (Sweden)

    Shang-Tse Ho

    2012-01-01

    Full Text Available The objective of this study is to assess antioxidant activities of methanolic extracts from the leaves of 18 indigenous tree species in Taiwan. Results revealed that, among 18 species, Acer oliverianum exhibited the best free radical scavenging activities. The IC50 values were 5.8 and 11.8 μg/mL on DPPH radical and superoxide radical scavenging activities, respectively. In addition, A. oliverianum also exhibited the strongest ferrous ion chelating activity. Based on a bioactivity-guided isolation principle, the resulting methanolic crude extracts of A. oliverianum leaves were fractionated to yield soluble fractions of hexane, EtOAc, BuOH, and water. Of these, the EtOAc fraction had the best antioxidant activity. Furthermore, 8 specific phytochemicals were isolated and identified from the EtOAc fraction. Among them, 1,2,3,4,6-O-penta-galloyl-β-D-glucopyranose had the best free radical scavenging activity. These results demonstrate that methanolic extracts and their derived phytochemicals of A. oliverianum leaves have excellent antioxidant activities and thus they have great potential as sources for natural health products.

  12. Antioxidant activities and phytochemical study of leaf extracts from 18 indigenous tree species in taiwan.

    Science.gov (United States)

    Ho, Shang-Tse; Tung, Yu-Tang; Chen, Yong-Long; Zhao, Ying-Ying; Chung, Min-Jay; Wu, Jyh-Horng

    2012-01-01

    The objective of this study is to assess antioxidant activities of methanolic extracts from the leaves of 18 indigenous tree species in Taiwan. Results revealed that, among 18 species, Acer oliverianum exhibited the best free radical scavenging activities. The IC(50) values were 5.8 and 11.8 μg/mL on DPPH radical and superoxide radical scavenging activities, respectively. In addition, A. oliverianum also exhibited the strongest ferrous ion chelating activity. Based on a bioactivity-guided isolation principle, the resulting methanolic crude extracts of A. oliverianum leaves were fractionated to yield soluble fractions of hexane, EtOAc, BuOH, and water. Of these, the EtOAc fraction had the best antioxidant activity. Furthermore, 8 specific phytochemicals were isolated and identified from the EtOAc fraction. Among them, 1,2,3,4,6-O-penta-galloyl-β-D-glucopyranose had the best free radical scavenging activity. These results demonstrate that methanolic extracts and their derived phytochemicals of A. oliverianum leaves have excellent antioxidant activities and thus they have great potential as sources for natural health products. PMID:22454657

  13. Environmental impacts of coastal farming: carbon and nitrogen budgets for trout farming activity in Kaldbaksfjørđur (Faroe Islands)

    DEFF Research Database (Denmark)

    Nordi, Gunnvør a; Glud, Ronnie N.; Gaard, Eilif;

    2011-01-01

    Flow of organic carbon (OC) and nitrogen through a sea cage trout farm was calculated on the basis of detailed studies of the farming operation, water circulation, OC and nutrient transport and recycling processes in sediment. A third of the OC and nitrogen provided by fish food was incorporated...... food input; the divergence between carbon efflux and oxygen uptake in sediment likewise increased with increasing food input, reflecting an increasing level of sediment reduction. Directly below the farm, the dissolved organic carbon (DOC) efflux was high (on average 53% of dissolved inorganic carbon...... efflux), indicating that DOC efflux is an important pathway for benthic carbon release below aquaculture farms. Overall, microbial processes removed 56 and 38% of OC and nitrogen, respectively, that settled to the seabed. ­During a 39 d break in farming activity, due to the combined effect...

  14. The effect of nitrogen and glyphosate on survival and colonisation of perennial grass species in an agro-ecosystem: does the relative importance of survival decrease with competitive ability?

    Directory of Open Access Journals (Sweden)

    Christian Damgaard

    Full Text Available The ecological success of a plant species is typically described by the observed change in plant abundance or cover, but in order to more fully understand the fundamental plant ecological processes, it is necessary to inspect the underlying processes of survival and colonization and how they are affected by environmental conditions. A general ecological hypothesis on the effect of environmental gradients on demographic parameters is proposed and tested. The hypothesis is that decreasing fitness or competitive ability along an environmental gradient is associated with an increasing importance of survival for regulating the abundance of the species. The tested hypothesis is related to both the stress gradient hypothesis and whether the importance of competition increases along productivity gradients. The combined effect of nitrogen and glyphosate on the survival and colonization probability of two perennial grass species, Festuca ovina and Agrostis capillaris, which are known to differ in their responses to both glyphosate and nitrogen treatments, is calculated using pin-point cover data in permanent frames. We found that the relative importance of survival increased with the level of glyphosate for the glyphosate sensitive A. capillaris and decreased for the glyphosate tolerant F. ovina. Likewise, increasing levels of nitrogen increased the importance of survival for the relative nitrophobic F. ovina. Consequently, the proposed hypothesis was corroborated in this specific study. The proposed method will enable predictions of the effects of agricultural practices on community dynamics in a relatively simple setup eliminating the need to quantify all the interaction among the species in the plant community. The method will be immediately useful for the regulation of non-cultivated buffer strips between agricultural fields and semi-natural and natural biotopes such as hedgerows and waterways.

  15. The effect of nitrogen and glyphosate on survival and colonisation of perennial grass species in an agro-ecosystem: does the relative importance of survival decrease with competitive ability?

    Science.gov (United States)

    Damgaard, Christian; Strandberg, Beate; Mathiassen, Solvejg K; Kudsk, Per

    2013-01-01

    The ecological success of a plant species is typically described by the observed change in plant abundance or cover, but in order to more fully understand the fundamental plant ecological processes, it is necessary to inspect the underlying processes of survival and colonization and how they are affected by environmental conditions. A general ecological hypothesis on the effect of environmental gradients on demographic parameters is proposed and tested. The hypothesis is that decreasing fitness or competitive ability along an environmental gradient is associated with an increasing importance of survival for regulating the abundance of the species. The tested hypothesis is related to both the stress gradient hypothesis and whether the importance of competition increases along productivity gradients. The combined effect of nitrogen and glyphosate on the survival and colonization probability of two perennial grass species, Festuca ovina and Agrostis capillaris, which are known to differ in their responses to both glyphosate and nitrogen treatments, is calculated using pin-point cover data in permanent frames. We found that the relative importance of survival increased with the level of glyphosate for the glyphosate sensitive A. capillaris and decreased for the glyphosate tolerant F. ovina. Likewise, increasing levels of nitrogen increased the importance of survival for the relative nitrophobic F. ovina. Consequently, the proposed hypothesis was corroborated in this specific study. The proposed method will enable predictions of the effects of agricultural practices on community dynamics in a relatively simple setup eliminating the need to quantify all the interaction among the species in the plant community. The method will be immediately useful for the regulation of non-cultivated buffer strips between agricultural fields and semi-natural and natural biotopes such as hedgerows and waterways.

  16. Responses of soil microbial communities and enzyme activities to nitrogen and phosphorus additions in Chinese fir plantations of subtropical China

    Directory of Open Access Journals (Sweden)

    W. Y. Dong

    2015-07-01

    Full Text Available Nitrogen (N and phosphorus (P additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-Glucosidase (βG and N-acetyl-β-D-glucosaminidase (NAG in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP activity was always higher (57 and 71 %, respectively in the P treatment. N and P additions greatly enhanced the PLFA abundanceespecially in the N2P treatment, the bacterial PLFAs (bacPLFAs, fungal PLFAs (funPLFAs and actinomycic PLFAs (actPLFAs were about 2.5, 3 and 4 times higher, respectively, than in the CK. Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC. βG or NAG activities were significantly and positively correlated with microbial PLFAs. There were also significant relationships between gram-positive (G+ bacteria and all three soil enzymes. These findings indicate that G+ bacteria is the most important microbial community in C, N, and P transformations in Chinese fir plantations, and that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote

  17. Chemical constituents and biological activities of species of Justicia: a review

    Directory of Open Access Journals (Sweden)

    Geone M. Corrêa

    2012-02-01

    Full Text Available The Acanthaceae family is an important source of therapeutic drugs, and the ethnopharmacological knowledge of this family requires urgent documentation as several of its species are near extinction. Justicia is the largest genus of Acanthaceae, with approximately 600 species. The present work provides a review addressing the chemistry and pharmacology of the genus Justicia. In addition, the biological activities of compounds isolated from the genus are also covered. The chemical and pharmacological information in the present work may inspire new biomedical applications for the species of Justicia, considering atom economy, the synthesis of environmentally benign products without producing toxic by-products, the use of renewable sources of raw materials, and the search for processes with maximal efficiency of energy.

  18. Optimum operating conditions for an adsorption cryocooler: a case of activated carbon + nitrogen system

    Energy Technology Data Exchange (ETDEWEB)

    Radhika Rani Rao [Don Bosco Institute of Technology, Bangalore (India). Dept. of Physics; Madhu Prasad [ISRO Satellite Centre, Bangalore (India). Thermal Systems Group; Kandadai Srinivasan [Indian Institute of Science, Bangalore (India). Dept. of Mechanical Engineering

    2005-03-01

    Adsorption cryocoolers are among the possible options for obtaining cryogenic temperatures, in particular for small cooling capacity applications such as cooling of infra red detectors. They need to be optimized for liquid yield. The performance of thermal compressors therein pivots around the adsorption characteristics of the adsorbent + adsorbate combination and how effectively one could pack requisite amounts of adsorbent into a given volume of the compressor housing. In addition, the overall performance of the cooler is a function of limits of operating temperatures and pressures across the compressor. This paper proposes a performance indicator-the product of liquid yield and the uptake efficiency of the compressor - and evaluates its values for various possible operating conditions for one specimen of activated carbon. It is shown that there is a limited domain of operation and that there is a condition of best performance within that domain. (author)

  19. Threatened and endangered wildlife species of the Hanford Site related to CERCLA characterization activities

    Energy Technology Data Exchange (ETDEWEB)

    Fitzner, R.E. [Pacific Northwest Lab., Richland, WA (United States); Weiss, S.G.; Stegen, J.A. [Westinghouse Hanford Co., Richland, WA (United States)

    1994-06-01

    The US Department of Energy`s (DOE) Hanford Site has been placed on the National Priorities List, which requires that it be remediated under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) or Superfund. Potentially contaminated areas of the Hanford Site were grouped into operable units, and detailed characterization and investigation plans were formulated. The DOE Richland Operations Office requested Westinghouse Hanford Company (WHC) to conduct a biological assessment of the potential impact of these characterization activities on the threatened, endangered, and sensitive wildlife species of the Hanford Site. Additional direction for WHC compliances with wildlife protection can be found in the Environmental Compliance Manual. This document is intended to meet these requirements, in part, for the CERCLA characterization activities, as well as for other work comparable in scope. This report documents the biological assessment and describes the pertinent components of the Hanford Site as well as the planned characterization activities. Also provided are accounts of endangered, threatened, and federal candidate wildlife species on the Hanford Site and information as to how human disturbances can affect these species. Potential effects of the characterization activities are described with recommendations for mitigation measures.

  20. Antifungal Activity of 14-Helical β-Peptides against Planktonic Cells and Biofilms of Candida Species

    Directory of Open Access Journals (Sweden)

    Namrata Raman

    2015-08-01

    Full Text Available Candida albicans is the most prevalent cause of fungal infections and treatment is further complicated by the formation of drug resistant biofilms, often on the surfaces of implanted medical devices. In recent years, the incidence of fungal infections by other pathogenic Candida species such as C. glabrata, C. parapsilosis and C. tropicalis has increased. Amphiphilic, helical β-peptide structural mimetics of natural antimicrobial α-peptides have been shown to exhibit specific planktonic antifungal and anti-biofilm formation activity against C. albicans in vitro. Here, we demonstrate that β-peptides are also active against clinically isolated and drug resistant strains of C. albicans and against other opportunistic Candida spp. Different Candida species were susceptible to β-peptides to varying degrees, with C. tropicalis being the most and C. glabrata being the least susceptible. β-peptide hydrophobicity directly correlated with antifungal activity against all the Candida clinical strains and species tested. While β-peptides were largely ineffective at disrupting existing Candida biofilms, hydrophobic β-peptides were able to prevent the formation of C. albicans, C. glabrata, C. parapsilosis and C. tropicalis biofilms. The broad-spectrum antifungal activity of β-peptides against planktonic cells and in preventing biofilm formation suggests the promise of this class of molecules as therapeutics.