Changes In Nitrogenous Compounds Research Articles

Co-existing water and sediment bacteria are driven by contrasting environmental factors across glacier-fed aquatic systems

Glacier-fed aquatic ecosystems provide habitats for diverse and active bacterial communities. However, the environmental vulnerabilities of co-existing water and sediment bacterial communities in these ecosystems remain unclear. Here, 16S rRNA gene sequencing was used to investigate co-existing bacterial communities in paired water and sediment samples from multiple rivers and lakes that are mainly fed by glaciers from the southeast Tibetan Plateau. Overall, the bacterial communities were dissimilar between the water and sediment, which indicated that there were limited interactions between them. Bacterial diversity was greatest in the sediments, where it was mainly driven by changes in nitrogen compounds and pH. Meanwhile water bacterial diversity was more susceptible to evapotranspiration, elevation, and mean annual temperature. Water samples contained higher proportions of Proteobacteria and Bacteroidetes, while sediment harbored higher proportions of Acidobacteria, Actinobacteria, Chloroflexi, Firmicutes, Planctomycetes, Cyanobacteria, and Gemmatimonadetes. Bacterial community composition was significantly correlated with mean annual precipitation in water, but with nitrogen compounds in sediment. The co-occurrence network of water included more keystone species (e.g., CL500–29 marine group, Nocardioides spp., and Bacillus spp.) than the sediment network. These keystone species showed stronger phylogenetic signals than the species in the modular structures. Further, ecological clusters within the networks suggested that there were contrasting environmental vulnerabilities and preferences between water and sediment communities. These findings demonstrated that co-existing water and sediment bacterial communities and ecological clusters were shaped by contrasting environmental factors. This work provides a basis for understanding the importance of bacterial communities in maintaining glacier-fed aquatic ecosystems. Further, the results provide new perspectives for water resource management and water conservation in changing environments.

The Influence of Various Forms of Nitrogen Fertilization and Meteorological Factors on Nitrogen Compounds in Soil under Laboratory Conditions

Nitrogen is one of the main factors that shapes soil fertility and the productivity of crops, although its abundance can also cause damage to the environment. The aim of this study is to evaluate the influences of different forms of nitrogen fertilizers, soil temperature, and precipitation on the changes of nitrogen compounds (N-NH4+, N-NO3−, and Nmin) in two soil layers. Two pot experiments are performed, involving simulated precipitation levels of 10- and 20 mm. Urea and ammonium nitrate fertilizers are used for fertilization. The soil samples are stored in pots in a climate chamber at different temperatures of 5, 10, 15, and 20 °C. After seven days, the changes of nitrogen compounds (N-NH4+, N-NO3−, and Nmin) in 0–15 and 15–30 cm soil layers are analyzed. This study shows that the amount of N-NH4+ nitrogen in the soil depends on the fertilizer form and soil temperature. In the temperature range of 5–20 °C, significantly more N-NH4+ nitrogen is present in urea-fertilized soil. The migration of N-NH4+ into the deeper 15–30 cm soil layer at both the 10- and 20-mm simulated precipitation levels is negligible. The N-NO3− contents in the 0–15 cm soil layer in the temperature range of 5–20 °C are 1.7–2.3 times lower in the urea-fertilized soil than in the ammonium nitrate-fertilized soil at a 10-mm simulated precipitation level and 1.6–2.2 times lower at 20 mm. The Nmin contents in soil are directly dependent on the fertilizer form and soil temperature for both levels of simulated precipitation.

Impact of chilling requirements on metabolic changes in nitrogenous compounds in buds during and after dormancy releasing in early and late (Malus sylvestris, Mill) apple varieties

Impact of chilling requirements on metabolic changes in nitrogenous compounds in buds during and after dormancy releasing in early and late (Malus sylvestris, Mill) apple varieties

Transformation and Transport Mechanism of Nitrogenous Compounds in a Biochar “Preparation–Returning to the Field” Process Studied by Employing an Isotope Tracer Method

Due to biochar’s excellent physical and chemical properties, such as rich void ration and large specific surface area, it could improve soil by conserving water and fertilizer and providing breeding grounds for soil microorganisms. Therefore, it has been attracting researchers’ interests for its potential as a soil amendment. In this work, elemental analysis-stable isotope ratio mass spectrometry (EA-IRMS) and X-ray photoelectron spectroscopy (XPS) were conjointly employed to investigate the migration and transformation mechanism of biochar nitrogenous compounds in the “preparation–returning” process. EA-IRMS data indicated that during the preparation process the nitrogen retention rate in biochar first dropped sharply (300–400 °C), then became stable (400–500 °C), and finally decreased slowly (500–800 °C) with increasing pyrolysis temperature. After returning biochar to soil, the measurable total nitrogen in biochar that migrated to soil and plants displayed a nitrogen mass distribution rate in the order of biochar after returning (88.40–90.42%) > soil (8.81–10.07%) > plants (0.77–1.53%). In addition, the pyrolysis temperature was negatively related to the nitrogen mass distribution rate in biochar, soil, and wheat. On the other hand, the pyrolysis atmosphere had little effect on the nitrogen retention rate in biochar before returning and the nitrogen mass distribution rate in biochar after returning to the field. XPS results suggested that alkaloid-N, free amino acid-N, protein-N, and NH4+-N in wheat straw were gradually transformed into pyridine-N, amino-N, pyrrole-N, quaternary-N, NH4+-N, NO2–-N, and NO3–-N in biochar during the biomass pyrolysis process. Biochar produced at 300 °C was in a transition stage that included all nitrogenous compounds present in wheat straw as well as biochar produced at the lower temperatures (≤500 °C). At higher temperatures, inorganic nitrogen species were more abundant and displayed higher contents. For pyrolysis temperatures ≤500 °C, biochars prepared under both N2 and CO2 atmospheres comprised similar nitrogenous compounds and contents. Moreover, the changes in nitrogenous compounds and nitrogen release patterns during the process of returning biochar to the field were not significantly different.

Structure and Composition Changes of Nitrogen Compounds during the Catalytic Cracking Process and Their Deactivating Effect on Catalysts

The comprehensive structure and composition changes of the nitrogen compounds during the catalytic cracking processes of coker gas oil and vacuum residue are investigated using electrospray ionization combined with Fourier transform ion cyclotron resonance mass spectrometry. These experiments were conducted over different cracking materials under the reaction temperatures of 500/520 °C, the weight hourly space velocity of 18 h–1, and the catalyst/oil ratio of 5. The results show that the diffusion resistance in the micropores of the zeolite is the key factor affecting the interaction between the nitrogen compounds and the acid sites. The basic N1 and N2 class species with double bond equivalence (DBE) values smaller than 10 can easily diffuse into the micropores of the zeolite and are preferentially adsorbed onto the acid sites. These adsorbed nitrogen compounds generally conduct condensation reactions and hydrogen transfer reactions to form coke deposited on the cracking catalysts. The basic N1 and N2 cl...

Changes of Nitrogen Compounds During Ensiling of High Protein Herbages – A Review

Abstract Losses of crude protein during ensiling of herbages, in contrast to carbohydrates, do not affect the reduction of its content; their form is changed into greater solubility non-protein compounds and also highly degraded forms, which lower the efficiency of the microbial protein synthesis in the rumen. These processes are accompanied by a change of amino acid composition of herbage protein and decrease in intestinal digestibility of protein from feeds as a result of the formation of indigestible complexes with carbohydrates (ADIN). Reduction of protein degradation in silages is achieved by accelerated acidity through addition of acids or dominance of homofermentative bacteria. The positive effects of fermentation inhibitors or sorbents use, as well as the wilting of raw material on the level and rate of protein degradation were demonstrated by many researchers. A greater contribution of protein nitrogen and reduction of deamination in silages can also be obtained by using bacteria inoculants. Increasing the proportion of protein nitrogen is accompanied by the improved efficiency of microbial protein synthesis.

Seasonal changes of nitrogen compounds in grown-up mulberry tree

Seasonal changes of nitrogen compounds in grown-up mulberry tree

Acute tolerance and metabolic responses of Chinese mitten crab ( Eriocheir sinensis) juveniles to ambient nitrite

The lethal concentration of nitrite to the Chinese mitten crab Eriocheir sinensis was tested by exposing the animals to 17.78, 23.71, 31.62, 42.17, and 56.23 mg NaNO 2 L − 1 at 20 °C for 24, 48, 72, and 96 h. The corresponding LC 50 value for each time exposure was 43.87 (38.70–51.70), 40.24 (34.88–46.01), 38.87 (33.72–46.01) and 38.87 (33.72–46.01) mg NaNO 2 L − 1 or 29.25 (25.80–34.47), 26.83 (23.25–30.67), 25.91(22.48–30.67), 25.91(22.48–30.67) mg NO 2–N L − 1 , respectively. The physiological response of the crab to nitrite toxicity was further investigated by exposing the crab to 0, 10, 20, 30 and 40 mg NaNO 2 L − 1 for 2 d. The changes of nitrogenous compounds in haemolymph, oxyhemocyanin and metabolism were measured at 3, 6, 24 and 48 h upon exposure. Haemolymph nitrite was significantly enhanced by the increase of nitrite from 10 to 40 mg NaNO 2 L − 1 during the 2-day exposure. The concentrations of nitrate, urea and glutamate in haemolymph increased concomitantly with the exposing time and ambient nitrite levels, suggesting that the formation of nitrate, urea and glutamine may be the possible end products of nitrite detoxification in crabs. The diffusion of nitrite caused a reduction of oxyhemocyanin, resulting to hypoxia in tissues. Under a hypoxia condition, crabs increased energy demand for metabolism as indicated by the elevated levels of glucose and lactate in haemolymph. Our data showed that ambient nitrite could affect oxygen carrying capacity through oxyhemocyanin reduction and the increase of energy catabolism in crabs. This study suggests that nitrite could be detoxified through the pathway of nitrate, urea and glutamine formation in crabs.

Amino acid pattern and glutamate metabolism during dehydration stress in the 'resurrection' plant Sporobolus stapfianus: a comparison between desiccation-sensitive and desiccation-tolerant leaves

The present study analyses changes in nitrogen compounds, amino acid composition, and glutamate metabolism in the resurrection plant Sporobolus stapfianus during dehydration stress. Results showed that older leaves (OL) were desiccation-sensitive whereas younger leaves (YL) were desiccation-tolerant. OL lost their soluble protein more rapidly, and to a larger extent than YL. Enzymes of primary nitrogen assimilation were affected by desiccation and the decrease in the glutamine synthetase (GS, EC 6.3.1.2) and ferredoxin-dependent GOGAT (Fd-GOGAT, EC 1.4.7.1) activities was higher in OL than in YL, thus suggesting higher sensibility to dehydration. Moreover, YL showed higher total GS enzyme activity at the end of the dehydration stress and was shown to maintain high chloroplastic GS protein content during the entire stress period. Free amino acid content increased in both YL and OL between 88% and 6% relative water content. Interestingly, OL and YL did not accumulate the same amino acids. OL accumulated large amounts of proline and gamma-aminobutyrate whereas YL preferentially accumulated asparagine and arginine. It is concluded (i) that modifications in the nitrogen and amino acid metabolism during dehydration stress were different depending on leaf development and (ii) that proline and gamma-aminobutyrate accumulation in S. stapfianus leaves were not essential for the acquisition of desiccation tolerance. On the contrary, the accumulation of large amounts of asparagine and arginine in the YL during dehydration could be important and serve as essential nitrogen and carbon reservoirs useful during rehydration. In this context, the role of GS for asparagine accumulation in YL is discussed.

Proteolysis during ripening of Manchego cheese made from raw or pasteurized ewes' milk. Seasonal variation

Changes in nitrogen compounds during ripening of 40 batches of Manchego cheese made from raw milk (24 batches) or pasteurized milk (16 batches) at five different dairies throughout the year were investigated. After ripening for six months, degradation of p-kappa- and beta-caseins was more intense in raw milk cheese and degradation of alpha(s2)-casein in pasteurized milk cheese. Milk pasteurization had no significant effect on breakdown of alpha(s1)-casein. Hydrophobic peptide content did not differ between raw and pasteurized milk cheese, whereas hydrophilic peptide content was higher in raw milk cheese. There were no significant differences between seasons for residual caseins, but hydrophobic peptides were at a higher level in cheese made in autumn and winter and hydrophilic peptides in cheese made in winter and spring. Raw milk cheese had a higher content of total free amino acids and of most individual free amino acids than pasteurized milk cheese. The relative percentages of the individual free amino acids were significantly different for raw milk and pasteurized milk cheeses. The relative percentages of Lys and lie increased, while those of Val, Leu and Phe decreased during ripening. There were also seasonal variations within the relative percentages of free amino acids. In raw milk cheeses, Asp and Cys were relatively more abundant in those made in autumn, Glu and Arg in cheeses made in winter, and Lys and Ile in cheeses made in spring and summer. Biogenic amines were detected only in raw milk cheese, with the highest levels of histamine, tryptamine and tyramine in cheeses made in spring, winter and spring, respectively.

Changes in Nitrogen Compounds in Berries of Six Grape Cultivars during Ripening over Two Years

Nitrogen compounds (free amino acids, peptides, and proteins) in the berries (juice, skins, and seeds) of six grape cultivars were studied to determine the amount of protein and changes in protein during ripening. Proteins were extracted totally and effectively from the skin and seeds at pH 12 with water. The amount of protein in juice and skins increased over time during ripening, whereas the amount of protein in seeds changed only slightly. Approximately 63% of total soluble and/or extractable nitrogen compounds in berries were proteins. Free amino acids and peptides comprised approximately 20 and 17% of all nitrogen compounds, respectively. Seeds contained on average approximately 50% of all the nitrogen compounds found in berries, primarily in the form of proteins. Juice and skins both contained approximately 25% of nitrogen compounds, and in juices these were primarily in the form of free amino acids. Proteins from these three tissues were rich in aspartic acid and glutamic acid, and similar amino acid compositions of proteins were observed in two different growing seasons for the same tissue of the same cultivar. Moreover, these compositions did not change appreciably during ripening. Amino acid compositions of proteins from the same tissue of different cultivars were similar. In comparisons of compositions of proteins from the three different tissues, a greater degree of similarity was observed between proteins from the juice and skin than between proteins from the juice and seeds or between proteins from the skin and seeds. Acknowledgments: The authors express their gratitude to Mr. Tohru Hosaka, of the Institute of Enology and Viticulture, Yamanashi University, for his technical assistance.

Release of nitrogen compounds to the extracellular medium by three strains of Saccharomyces cerevisiae during induced autolysis in a model wine system

To detect differences among three strains of Saccharomyces cerevisiae used in the manufacture of sparkling wines and to study the changes in nitrogen compounds during autolysis, a model wine system was used. Significant differences were observed between the mean values of the autolytic capacity of the three strains. The amount of nitrogen (total, protein, peptide and amino) present in the autolysates and the concentration of most free amino acids was significantly affected by the strain. These findings suggest that the strain of yeast used in the manufacture of sparkling wines can play an important role in the aging process and can affect final composition.

Changes in nitrogen compounds in must and wine during fermentation and biological aging by flor yeasts.

Urea, ammonium, and free amino acid contents were quantified in a must from Vitis vinifera cv. Pedro Ximenez grapes and in fermented wine and after a short aging of this wine by Saccharomyces cerevisiae race capensis yeast under variable oxygen availability conditions. The previous compounds were also determined in a wine in which the nitrogen source was depleted by the same race of flor yeast (old wine) and also following the addition of ammonium ion, L-glutamic acid, and L-proline. Under specific conditions such as low oxygen level and the absence of some nutrients, the yeasts release some amino acids including L-threonine, L-tryptophan, L-cysteine, and L-methionine to the medium. These amino acids must originate primarily in a de novo synthesis from ethanol that regenerates NAD(P)+. On the basis of these results, the yeasts may be able to use amino acids not only as nitrogen sources but also as redox agents to balance the oxidation-reduction potential under conditions of restricted oxygen, when electron transport along the respiratory chain may be hindered or limited.

Changes in nitrogenous compounds, carbohydrates and abscisic acid in Curcuma alismatifolia Gagnep. during dormancy

SummaryStubbed rhizomes of Curcuma alismatifolia Gagnep. were kept at room temperature with good ventilation during their dormant period and then were randomly sampled at different stages of dormancy, i.e. stage 1 (beginning of dormancy), stage 2 (middle of dormancy) and stage 3 (late in dormancy with the buds sprouting). Fresh and dry weights, water content, nitrogencontent and starch and total soluble sugar content decreased in the stubbed rhizome and storage roots during dormancy. Therhizome was the principal organ for N storage and the storage roots were the major organ for carbohydrate storage. Argin ne and glutamic acid were the predominant free amino acids in the rhizome and storage roots, respectively. Free abscisic acid in the rhizome increased from stage 1 to 2 and then decreased by stage 3, while the concentration in storage roots decreased continuously until buds sprouted.

Assessing Compositional Changes of Nitrogen Compounds during Hydrotreating of Typical Diesel Range Gas Oils Using a Novel Preconcentration Technique Coupled with Gas Chromatography and Atomic Emission Detection

This paper describes the identification of nitrogen-containing compounds in a typical feed for diesel oil hydrotreating and how their individual concentrations change upon hydrotreating over a conventional sulfided CoMo/Al2O3 catalyst at commercial conditions. A preconcentration procedure followed by gas chromatographic (GC) analysis utilizing a highly sensitive nitrogen-specific detector (atomic emission detector) allowed the quantitative analysis of individual nitrogen-containing compounds (N compounds) at levels as low as 0.05 μg N/mL. The nitrogen compounds in the feed and products were identified by comparison with reference compounds as well as by high-resolution GC/mass spectrometric characterization. The relative reactivities of individual compounds in the diesel fuel feed were determined and the most refractory compounds identified. Alkyl-substituted carbazoles were found to be the major compound class in the feed and to be among the least reactive N compounds in the feed. Just as in the case of ...

Oxides of nitrogen and ozone: can our plants survive?

The authoritative talk by Professor Fowler (Fowler et al., 1998), emphasized the huge increase in the rate of NOx (NO and NO2) emissions into the atmosphere due to fossil fuel combustion, from 1 Tg N y−1 to over 20 Tg N y−1 during the 100 yr between 1880 and 1980. He went on to predict that this rate of emission from anthropogenic sources would increase to 46 Tg N y−1 by the year 2025. In addition, NO can also be released from the soil following microbial action, a process that is very dependent upon soil temperature, nitrogen availability and water content. Later in the meeting, Professor Raven (Raven & Yin, 1998) pointed out that terrestrial plants, though not necessarily each individual species, have over the past 450 million yr coped with large changes in nitrogenous compounds in the environment. Nevertheless, this is no basis for complacency about the current situation because the rates of change caused by man's activities are probably unprecedented. Furthermore, the fact that terrestrial plant life in some form can continue, despite massive changes in environmental chemistry, does not necessarily indicate that the systems on which we ourselves are dependent will be conserved.

Changes in Nitrogenous Compounds and Rates of in Situ N Loss of Soybean Meal Treated with Sodium Hydroxide or Heat

Rates of in situ N loss of soybean meal (SBM) were altered by various combinations of sodium hydroxide and heat treatment; some nitrogenous compounds involving the modified proteolysis were investigated. The amount of lysinoalanine (LAL), neutral detergent insoluble nitrogen, 1-fluoro-2,4-dinitrobenzene reactive lysine, and reducing power of SBM were linearly related (P < 0.01) to rate of in situ N loss with correlation coefficients of −0.847, −0.835, 0.793, and −0.846, respectively. The results indicate that the LAL formation and the Maillard reaction are related to change in susceptibility of SBM protein to microbial degradation in the rumen. Keywords: Lysinoalanine; in situ N loss; nonenzymatic browning; feed processing

Ruminal degradation of alfalfa protein as influenced by sodium hydroxide and heat treatment

Effects of sodium hydroxide (NaOH) and heat treatment of alfalfa on the degradation of protein in the rumen was investigated in relation to the changes of nitrogenous compounds. Fresh alfalfa was treated with 0, 1.16, 2.32 or 4.64 g NaOH per 100 g dry matter (DM) and then subjected to freeze-drying, or oven-drying for 24 h at 60 or 120°C. Both NaOH and heat treatment produced lysinoalanine at increasing rate with level of treatment to reach a maximum value of 238 mg per 100 g protein. Both treatments also increased neutral detergent insoluble nitrogen (NDIN) according to the increase in level of treatment. Acid detergent insoluble nitrogen (ADIN) was not affected by NaOH treatment but was significantly increased by heating at 120°C. Both NaOH and heat treatment modified protein into being less soluble and more slowly degradable in the rumen, but heating showed greater effects than NaOH treatment. The proportion of potentially degradable protein was little influenced by the treatments. Both NaOH and heat treatment decreased the rate of protein degradation, but significant differences were detected only with the highest level of treatment (4.64 g NaOH per 100 g DM or 120°C). Correlation coefficients of lysinoalanine, NDIN and ADIN content with rate of protein degradation in the rumen were −0.716, −0.950 and −0.834, respectively. These results suggest that lysinoalanine formation in protein by NaOH and heat treatment can make protein less susceptible to microbial degradation in the rumen, while protein-carbohydrate reaction enhanced the effects on protein degradation in this study.

Chemical changes in nitrogenous compounds during fermentation of sour doughs and bread doughs

The evolution of sour doughs (SD), prepared using a wheat bran extract as the starting material, and their respective bread doughs (BD) has been investigated by determining the chemical changes which take place in 0.85 mol/L NaCl-soluble nitrogen compounds during fermentation. The quantitative changes determined are: total nitrogen content (TN), primary amine nitrogen (AN) andα-amine nitrogen of free amino acids (AAN) in the total soluble fraction (SN), protein (PSN) and non-protein (NPSN) subfractions. During fermentation,α-amine nitrogen of the free amino acids (AANSN) and peptides (ANNPSN-AANSN), increase in SD and decrease in BD. Changes are larger and faster in peptide nitrogen and even larger during the third and fifth steps. The total protein content (TNPSN) decreases in both SD and BD. Results are discussed in relation to the quality of the bread obtained in each case.

パーボイルド米膠の含窒素化合物の動向

パーボイルド米膠の含窒素化合物の動向