Amino N (amino + n)

Distribution by Scientific Domains


Selected Abstracts


Accumulation of heterocyclic nitrogen in humified organic matter: a 15N-NMR study of lowland rice soils

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2000
N. Mahieu
Summary Recent intensification of cropping and the attendant longer submergence of the soil for lowland rice in tropical Asia appear to have altered the nature of the soil organic matter, and perhaps also nutrient cycling. To identify the dominant forms of organic nitrogen in the soils we extracted the labile mobile humic acid (MHA) and the more recalcitrant calcium humate (CaHA) fractions from soils under several long-term field experiments in the Philippines and analysed them by 15N-nuclear magnetic resonance spectroscopy. Amide N dominated the spectra of all humic acid (HA) samples (60,80% of total peak area). Its proportion of total spectral area increased with increasing intensity of cropping and length of time during which the soil was flooded and was greater in the MHA fraction than in the CaHA fraction. Simultaneously the spectral proportion of free amino N and other chemical shift regions decreased slightly with increasing length of submergence. Heterocyclic N was detected at modest proportions (7,22%) and was more prevalent in more humified samples, especially in the CaHA of aerated soils. Correlations of spectral proportions of heterocyclic N with other properties of the HA, reported elsewhere, were highly significant. Correlations were positive with visible light absorption (r=,0.86) and concentration of free radicals (r=,0.85), both of which are indices of humification, and negative with concentration of H (r=,,0.86), a negative index of humification. Correlations of spectral proportions of amide N with these properties were also highly significant but in each case of opposite sign to that of heterocyclic N. Proportions of heterocyclic N declined with increasing duration of submergence. The results suggest that (i) 15N-NMR can reproducibly measure some portion of heterocyclic N, (ii) formation of heterocyclic N is associated solely with gradual humification occurring over many years, and (iii) the abundant phenols in the submerged rice soils did not promote formation of heterocyclic N, and hence some other process is responsible for a substantial decrease in the availability of native N associated with intensive rice cropping. [source]


Effect of N Fertilization Rate on Sugar Yield and Non-Sugar Impurities of Sugar Beets (Beta vulgaris) Grown Under Mediterranean Conditions

JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2005
J. T. Tsialtas
Abstract For three successive growing seasons (1999,2001), a completely randomized block design experiment was established at the surrounding area of each of four sugar beet processing plants of Hellenic Sugar Industry SA, Greece (a total of 12 experiments). Nitrogen was applied at five rates (0, 60, 120, 180 and 240 kg N ha,1) and six replications per rate. Nitrogen fertilization had site-specific effects on quantitative (fresh root and sugar yields) and qualitative (sucrose content, K, Na, , -amino N) traits. When data were combined over years and sites, fresh root and sugar yields were maximized at high N rates (330.75 and 295 kg N ha,1 respectively), as derived from quadratic functions fitted to data. In three trials, increased N rates had negative effects on root and sugar yield. These sites were characterized by high yield in control plots, light soil texture (sand > 50 %) and low CEC values. When data were converted into relative values (the ratio of the trait values to the control mean of each experiment), root and sugar yield was found to be maximized at higher N rates (350 and 316 kg N ha,1, respectively). Sucrose content was strongly and linearly reduced by the increased N rates when data were combined but a significant reduction with increasing N rates was found in only two sites. Non-sugar impurities (K, Na, , -amino N) were positively related to the increased N rates when data were combined. Sodium and , -amino N showed to be most affected by N fertilization as positive relationships were found in six and eight of 12 locations, respectively. Increased N supply resulted in higher soil NO3 -N concentrations (0,90 cm depth) at harvest which were related with amino N contents in sugar beet roots (in 1999 and 2001). [source]


Effects of glucose and amino acids on ghrelin secretion in sheep

ANIMAL SCIENCE JOURNAL, Issue 2 2010
Toshihisa SUGINO
ABSTRACT Two experiments were conducted to elucidate the effects of post-ruminal administration of starch and casein (Exp. 1), plasma amino acids concentrations (Exp. 2), and plasma glucose and insulin concentrations (Exp. 2) on plasma ghrelin concentrations in sheep. In Exp. 1, plasma ghrelin concentrations were determined by four infusion treatments (water, cornstarch, casein and cornstarch plus casein) in four wethers. Abomasal infusion of casein increased plasma ,-amino N (AAN) concentrations. Infusion of starch or casein alone did not affect plasma ghrelin concentrations, but starch plus casein infusion increased plasma levels of ghrelin, glucose and AAN. In Exp 2, we investigated the effects of saline or amino acids on ghrelin secretion in four wethers. Two hours after the initiation of saline or amino acid infusion into the jugular vein, glucose was also continuously infused to investigate the effects of blood glucose and insulin by hyper-glycemic clump on plasma ghrelin concentrations. Infusion of amino acids alone raised plasma levels of ghrelin, but the higher plasma glucose and insulin concentrations had no effect on plasma ghrelin concentrations. These results suggest that high plasma levels of amino acids can stimulate ghrelin secretion, but glucose and insulin do not affect ghrelin secretion in sheep. [source]


Conformational isomers of the [(5-methyl-2-pyridinio)aminomethylene]diphosphonate dianion and [(5-methyl-2-pyridyl)aminomethylene]diphosphonate trianion in salts with 4-aminopyridine and ammonia

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2009
Ewa Matczak-Jon
The crystal structures of two salts, products of the reactions between [(5-methyl-2-pyridyl)aminomethylene]bis(phosphonic acid) and 4-aminopyridine or ammonia, namely bis(4-aminopyridinium) hydrogen [(5-methyl-2-pyridinio)aminomethylene]diphosphonate 2.4-hydrate, 2C5H7N2+·C7H10N2O6P22,·2.4H2O, (I), and triammonium hydrogen [(5-methyl-2-pyridyl)aminomethylene]diphosphonate monohydrate, 3NH4+·C7H9N2O6P23,·H2O, (II), have been determined. In (I), the Z configuration of the ring N,C and amino N,H bonds of the bisphosphonate dianion with respect to the Cring,Namino bond is consistent with that of the parent zwitterion. Removing the H atom from the pyridyl N atom results in the opposite E configuration of the bisphosphonate trianion in (II). Compound (I) exhibits a three-dimensional hydrogen-bonded network, in which 4-aminopyridinium cations and water molecules are joined to ribbons composed of anionic dimers linked by O,H...O and N,H...O hydrogen bonds. The supramolecular motif resulting from a combination of these three interactions is a common phenomenon in crystals of all of the Z -isomeric zwitterions of 4- and 5-substituted (2-pyridylaminomethylene)bis(phosphonic acid)s studied to date. In (II), ammonium cations and water molecules are linked to chains of trianions, resulting in the formation of double layers. [source]