Various Concentrations Of Ammonium Research Articles

Transcriptomic Sequencing and Co-Expression Network Analysis on Key Genes and Pathways Regulating Nitrogen Use Efficiency in Myriophyllum aquaticum.

Massively input and accumulated ammonium is one of the main causes of eutrophication in aquatic ecosystems, which severely deteriorates water quality. Previous studies showed that one of the commonly used macrophytes, Myriophyllum aquaticum, was capable of not only withstanding ammonium of high concentration, but also efficiently assimilating extracellular ammonium to constitutive amino acids and proteins. However, the genetic mechanism regulating such efficient nitrogen metabolism in M. aquaticum is still poorly understood. Therefore, RNA-based analysis was performed in this study to understand the ammonium regulatory mechanism in M. aquaticum in response to various concentrations of ammonium. A total of 7721 genes were differentially expressed, of which those related to nitrogen-transport, assimilation, and remobilization were highly-regulated in response to various concentrations of ammonium. We have also identified transcription factors and protein kinases that were rapidly induced in response to ammonium, which suggests their involvement in ammonium-mediated signalling. Meanwhile, secondary metabolism including phenolics and anthocyanins biosynthesis was also activated in response to various concentrations of ammonium, especially at high ammonium concentrations. These results proposed a complex physiological and genetic regulation network related to nitrogen, carbohydrate, transcription factors, and secondary metabolism for nitrogen use efficiency in M. aquaticum.

Nanotubular polypyrrole: Reversibility of protonation/deprotonation cycles and long-term stability

An alteration of electrical conductivity of the conducting polymers from a conducting to a non-conducting form and vice versa is a feature of the high importance. Here, the changes in conductivity of the polypyrrole nanotubes (PPy-NT) associated with a deprotonation/reprotonation in alkaline (various concentrations of ammonium or sodium hydroxide) or acidic (1 M hydrochloric or hydrobromic acid) solutions are presented. All experiments were followed by energy dispersive X-ray spectroscopy (EDX) elemental analyses and van der Pauw conductivity measurements. Extensive measurements of conductivity of samples during 2-years' timespan have also been made in order to determine the kinetics of natural ageing of the deprotonated/reprotonated PPy-NT. EDX measurements have allowed for a deeper insight into the process of the deprotonation/reprotonation of PPy-NT, which is generally characterized by the exchange of counter-ions and by the increase in the oxygen content. Correlations among conductivities of original, deprotonated and reprotonated samples revealed the universal behaviour, which can be used for the precise prediction of the ability of PPy-NT to be reprotonated by acids. Kinetics of the degradation of PPy-NT by natural ageing is faster for deprotonated sample and, on the contrary, the reprotonation by acids had a stabilizing effect.

Highly efficient partial nitrification by polyvinyl alcohol–alginate immobilized cells

Partial nitrification (oxidation of ammonium to nitrite by ammonium-oxidizing bacteria (AOB)) is a critical step in the process of removing biological nitrogen from nitrite. However, nitrite is unstable and easily oxidized to nitrate by nitrite-oxidizing bacteria (NOB) under aerobic conditions. In this study, a polyvinyl alcohol–alginate immobilization technique was utilized to entrap nitrifying bacteria for partial nitrification. The experimental results demonstrated that such immobilization limited the diffusion of dissolved oxygen (DO) into the immobilized cells to inhibit the activity of NOB. In this manner, stable and highly efficient partial nitrification was achieved. Nearly all of the ammonium was converted to nitrite rather than nitrate when the concentration of DO was between 0.5 and 2.0 mg L−1. Partial nitrification was also easily achieved at various concentrations of ammonium. Fluorescence in situ hybridization analysis indicated that AOB was the dominant bacteria in the immobilized cells (representing approximately 96% of the total microbial population).

Effect of Ammonium and Nitrate on Current Generation Using Dual-Cathode Microbial Fuel Cells

These studies were conducted to determine the effects of various concentrations of ammonium and nitrate on current generation using dual-cathode microbial fuel cells (MFCs). Current generation was not affected by ammonium up to 51.8+/-0.0 mg/l, whereas 103.5+/-0.0 mg/l ammonium chloride reduced the current slightly. On the other hand, when 60.0+/-0.0 and 123.3+/-0.1 mg/l nitrate were supplied, the current was decreased from 10.23+/-0.07 mA to 3.20+/-0.24 and 0.20+/-0.01 mA, respectively. Nitrate did not seem to serve as a fuel for current generation in these studies. At this time, COD and nitrate removal were increased except at 123+/-0.1 mg NO(3)(-)/l. These results show that proper management of ammonium and nitrate is very important for increasing the current in a microbial fuel cell.

Heterotrophic ammonium removal characteristics of an aerobic heterotrophic nitrifying-denitrifying bacterium, Providencia rettgeri YL

Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4+-N). In order to further understand its removal ability, several experiments were conducted to identify the growth and ammonium removal response at different carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30 degrees C, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth, respectively. The nitrification products hydroxylamine (NH2OH), nitrite (NO2(-)) and nitrate (NO3(-)) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions.

Trigonal distortion of water octahedron surrounding trivalent chromium ion

Abstract Mixed crystals of ammonium aluminium alum and thallium aluminium alum are grown with various concentrations of ammonium and thallium with chromium as dopant. The optical absorption spectra and EPR spectra are recorded and analysed. Variation of zero field splitting parameter (D) with concentration of thallium is studied in EPR spectra. The increase in the value of D with increasing concentration of thallium atoms is predicted to be due to the trigonal distortion caused by these atoms in the co-ordinating water octahedron. These results are also supported by the splitting of one of the bands in the optical absorption spectrum which is attributed to the trigonal distortion and increase in splitting with increase of thallium atom concentration.

Growth of some strains ofStigeoclonium(Chlorophyta) on nitrate, ammonium, ammonium nitrate and urea

Nine unialgal strains of five Stigeoclonium species were cultured in synthetic medium with various concentrations of ammonium, nitrate, ammonium nitrate and urea. Growth responses to 5 mg N1-1 of the various nitrogen sources varied only a little. All strains grew well in media with concentrations of nitrate and urea between 12·5 and 25 mg N1-1. Ammonium concentrations beyond 5 and 12·5 mg N1-1 inhibited the yield of most cultures, while yields obtained with NH4NO3 showed intermediate values to NO3 and NH4 as sole nitrogen sources. It is most unlikely that nitrate attains saturation levels in the field, but concentrations of ammonium may be high enough to inhibit growth of Stigeoclonium at certain sites. A clear relationship between growth responses of the strains and the nitrogen levels of their original field situation was not found. The justification for comparing bioassay results with the inorganic nitrogen or total nitrogen concentration of the testwater is discussed.

Effect of ammonium concentration on growth and nitrogen accumulation by soybean grown in nutrient solution

Soybean (Glycine max (L.) MERR. CV. ‘Amsoy’) plants were grown for 40 days in nutrient solution at various concentrations of ammonium. Maximum yield of dry matter was obtained at a concentration of 715 μM. Further increase in the concentration of ammonium resulted in a reduction in growth due to ammonium toxicity which affected both root and shoot development. The pattern of nitrogen accumulation in tops was consistent with the multiphasic uptake of ammonium and can be represented by 2 phases in the range 1.78 X 10-5-3.57 x X 10-3 M of ammonium.

Ammonium Regulation in Aspergillus nidulans

l-Glutamate uptake, thiourea uptake, and methylammonium uptake and the intracellular ammonium concentration were measured in wild-type and mutant cells of Aspergillus nidulans held in various concentrations of ammonium and urea. The levels of l-glutamate uptake, thiourea uptake, nitrate reductase, and hypoxanthine dehydrogenase activity are determined by the extracellular ammonium concentration. The level of methylammonium uptake is determined by the intracellular ammonium concentration. The uptake and enzyme characteristics of the ammonium-derepressed mutants, meaA8, meaB6, DER3, amrA1, xprD1, and gdhA1, are described. The gdhA mutants lack normal nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase (NADP-GDH) activity and are derepressed with respect to both external and internal ammonium. The other mutant classes are derepressed only with respect to external ammonium. The mutants meaA8, DER3, amrA1, and xprD1 have low levels of one or more of the l-glutamate, thiourea, and methylammonium uptake systems. A model for ammonium regulation in A. nidulans is put forward which suggests: (i) NADP-GDH located in the cell membrane complexes with extracellular ammonium. This first regulatory complex determines the level of l-glutamate uptake, thiourea uptake, nitrate reductase, and xanthine dehydrogenase by repression or inhibition, or both. (ii) NADP-GDH also complexes with intracellular ammonium. This second and different form of regulatory complex determines the level of methylammonium uptake by repression or inhibition, or both.

Ammonium Regulation in Aspergillus nidulans

Conference Article| May 01 1973 Ammonium Regulation in Aspergillus nidulans J. A. PATEMAN; J. A. PATEMAN 1Department of Genetics, University of Glasgow, Glasgow G11 5JS, U.K. Search for other works by this author on: This Site PubMed Google Scholar J. R. KINGHORN; J. R. KINGHORN 1Department of Genetics, University of Glasgow, Glasgow G11 5JS, U.K. Search for other works by this author on: This Site PubMed Google Scholar ETTA DUNN; ETTA DUNN 1Department of Genetics, University of Glasgow, Glasgow G11 5JS, U.K. Search for other works by this author on: This Site PubMed Google Scholar E. FORBES E. FORBES 1Department of Genetics, University of Glasgow, Glasgow G11 5JS, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1973) 1 (3): 674–675. https://doi.org/10.1042/bst0010674 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Cite Icon Cite Get Permissions Citation J. A. PATEMAN, J. R. KINGHORN, ETTA DUNN, E. FORBES; Ammonium Regulation in Aspergillus nidulans. Biochem Soc Trans 1 May 1973; 1 (3): 674–675. doi: https://doi.org/10.1042/bst0010674 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search This content is only available as a PDF. © 1973 Biochemical Society1973 Article PDF first page preview Close Modal You do not currently have access to this content.