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PubMed2005

Eutrophication trends in forest soils in Galicia (NW Spain) caused by the atmospheric deposition of nitrogen compounds.

We calculated the sensitivity of Galician forest soils to eutrophication caused by atmospheric deposition of nitrogen compounds, using the Simple Mass Balance (SMB) method as described by [Posch, M., de Vries, W., Hettelingh, J.-P., 1995. Critical loads of sulphur and nitrogen. In: Posch, M., de Smet, P.A.M., Hettelingh, J.-P., Downing, R.J. Calculation and Mapping of Critical Thresholds in Europe. Status Report 1995, Coordination Center for Effects, National Institute for Public Health and the Environment, Bilthoven, The Netherlands, pp. 31-42]. Deposition values were used to calculate critical loads exceedance. Galician natural forest ecosystems can support nitrogen deposition loads of more than 10 kg Nha (-1) yr (-1). The lowest critical loads (approximately 10 kg Nha (-1) yr (-1)) mainly occurred in forest stands in the interior zone, while highest critical load values (approximately 68 kg Nha (-1) yr (-1)) were observed in eucalyptus stands at low altitudes in the littoral area. Exceedances based on N deposition levels, calculated from data recorded in 2001, occurred in 40% of the forest soils, showing the need to control N emissions in these areas to prevent possible eutrophication of soils and waters. Analysis of rainfall bulk composition revealed that ammonium, probably derived from agricultural and cattle activities, was the main compound responsible for N deposition in Galicia.

Air Pollutants↗
PubMed2003

Comparing differentiation of xylene isomers by electronic ionization, chemical ionization and self-ion/molecule reactions and the first observation of methyne addition ions for xylene isomers in self-ion/molecule reactions for non-nitrogenated compounds.

This study presents the self-ion/molecule reaction (SIMR) spectra of three xylene isomers, and proposes an approach to differentiating them based on observed differences in relative abundances of ions formed by SIMR in an internal source ion trap instrument. It also demonstrates the applicability of SIMR for isomer discrimination, which is better than electron ionization (EI) and dimethyl ether chemical ionization (DME CI) in an ion trap mass spectrometer (ITMS) since no CI reagent, metal ions or internal standards are required to perform SIMR. The merits of the new method for distinguishing isomers are that it is simple, rapid and economic. To date, methyne addition products ([M+13](+) ions) have been observed for several nitrogenated compounds including aza-crown ethers, aniline and dopamine from SIMR in the ITMS. The xylene isomers are, however, the first three non-nitrogenated compounds that have been shown to produce the methyne addition ions in SIMR.

Journal Article↗
PubMed1981

Di- and tri-methoxystyryl derivatives of heterocyclic nitrogen compounds.

A series of mono-, di-, and trimethoxystyryl derivatives of heterocyclic nitrogen compounds were prepared to test the N-O-O triangulation hypothesis of Zee-Cheng and Cheng. Of 29 free bases submitted for KB cell culture test, only 2-(3,4-methylenedioxystyryl)benzoxazole and 4-(2,5-dimethoxystyryl)cinnoline were active (ED50 of 4 microgram/ml or less). Methiodide salts were more potent: 8 of 14 were active. 2-(2,4,6-Trimethoxystyryl)quinoline methiodide and 4-(2,4,5-trimethoxystyryl)quinoline methiodide had ED50 of 0.4 and 0.9 microgram/ml, respectively. The methiodides of 2-(2,3,4-, 4-(2,4,5-, 4-(2,4,6-, and 2,4-bis-(2,4,6-trimethoxystyryl)quinoline and 1-(2,4,6-trimethoxystyryl) isoquinoline and the propiodide of 4-(2,4,6-trimethoxystyryl)quinoline were active against P388 leukemia. Several of the active compounds do not conform to the dimensions of the Zee-Cheng and Cheng triangle.

Animals↗
PubMedDate not supplied

[Normalization of impairments in deamination of nitrogen compounds in experimental hypercholesterolemia].

Appearance of cadaverine deaminating activity in mitochondrial fractions of liver and kidney of rabbits with experimental alimentary hypercholesterolaemia was prevented by an antioxant diludin (2,6-dimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridine) which also decreased the abnormally elevated AMP-deaminating activity and elevated the decreased monoamine oxidase activity (substrates: serotonin, benzylamine, tyramine). In heart and brain tissues as compared with liver and kidney the impairments caused by hypercholesterolaemia and the normalizing effect of diludin were less distinct. The effects of diludin could be reproduced by nucleophylic reagents sodium thiosulphate or ascorbate. The normalization of impairments in deamination of nitrogenous compounds in hypercholesterolaemia was accompanied by improvement in morpho-physiological manifestations of atherosclerosis (injury of aortal intima, alteration in heart rhythm, changes in content of cholesterol, triglycerides and lipoproteins in blood serum). The data obtained are in agreement with the hypothesis on the significance of qualitative alteration (transformation) in catalytic properties of mitochondrial monoamine oxidases in the mechanism of impairments in deamination of nitrogenous compounds in atherosclerosis.

AMP Deaminase↗
PubMed2003

[Effect of inorganic nitrogen compounds and pH on the growth of duckweed].

The use of duckweed in domestic wastewater treatment was paied increasing attention recently. But inorganic nitrogen compounds and pH of wastewater possibly affect the growth of duckweed. The effect of ammonia, nitrate and pH on the growth of Lemna minor L., a common spiece in China, was assessed with laboratory scale experiments. The experiments used artificial culture with different levels of pH, ammonia and nitrate concentrations. The experimental results indicated that the lowest value of pH Lemna minor can tolerate was between 5-6, and it can grow well in pH from 6 to 9. The growth rate of Lemna minor was inhibited gradually with increasing concentration of ammonia. The toxicity of ammonia was a result of both forms, NH3 and NH4+. Compared to NH4+, the effect of NH3 was much stronger. Nitrate had few inhibitory on the growth of Lemna minor. The increase in ammonia and nitrate concentrations can increase the chloropyll content of Lemna minor. Activity of peroxidase of Lemna minor in ammonia culture was higher than that in nitrate culture because of the toxicity of ammonia.

Ammonia↗
PubMedDate not supplied

[Utilization of nitrogen compounds by phototrophic bacteria].

Phototrophic purple and green bacteria differ by their ability to assimilate nitrogen compounds. Thiocapsa roseopersicina utilizes not only ammonium and nitrates, as a source of nitrogen, but also urea, azoguanine, cytosine and some amino acids. The non-sulphur bacterium Rhodopseudomonas palustris grows at the account of amine nitrogen of a larger number of amino acids than the sulphur bacterium. Chlorobium limicola 1. thiosulfatophilum grows only on media containing urea and methylamines. Formation of amino acids by the studied phototrophic bacterial cultures is related to amination of alpha-ketoglutarate. Purple bacteria possess also the activity of aspartate dehydrogenase.

Amino Acids↗
PubMed1962

Conditions affecting Bacillus megaterium spore germination in glucose or various nitrogenous compounds.

Hyatt, Mildred T. (Quartermaster Research and Engineering Center, Natick, Mass.) and Hillel S. Levinson. Conditions affecting Bacillus megaterium spore germination in glucose or various nitrogenous compounds. J. Bacteriol. 83:1231-1237. 1962.-The possibility that there is more than one metabolic pathway for triggering germination of Bacillus megaterium spores was investigated. Spores were germinated in seven different "physiological germinants" under varying conditions of concentration, pH, combinations of germinants, temperature before and during germination, and chemical inhibition. l-Alanine and l-valine appear to induce germination via the same metabolic pathway (same inhibitors are effective, similar germination rate and temperature requirements); and glucose and glucosamine also appear to act similarly, but by a different pathway than l-alanine and l-valine. The other germinants, l-leucine, l-proline, and KNO(3), do not correspond in all respects either to the glucose-glucosamine or to the alanine-valine pair in response to the different germination conditions. It is concluded that B. megaterium spore germination occurs via more than one pathway.

Alanine↗
PubMed2002

Yeast adapted to wine: nitrogen compounds released during induced autolysis in a model wine.

As important as the blend of base wines before bottling, one of the most important steps in the champagne-making process is the long ageing on lees. Two yeast strains of Saccharomyces cerevisiae MC001 and MC002, used in champagne wine production, were allowed to autolyse. After 8 days of autolysis, active dry yeasts adapted to wine released 1.7- to 1.8-fold more nitrogen compounds than nonadapted active dry yeast. The nitrogen content (total, proteins, peptides and amino) present in autolysates was measured for yeasts adapted to wine. The composition of free amino acids and amino acids constituting peptides showed no difference between the two strains of yeast used. Studies of intracellular proteolytic activity and release of peptides showed no correlation between these two phenomena. These results indicate that yeasts adapted to wine give results similar to those that occur in wine during ageing.

Amino Acids↗
PubMed1977

Nitrogen fixation (acetylene reduction) in a salt marsh amended with sewage sludge and organic carbon and nitrogen compounds.

Seasonal distribution of nitrogen fixation by Spartina alterniflora epiphytes and in surface and soil samples was investigated in a Georgia salt marsh which was amended with sewage sludge or with glucose and/or ammonium nitrate. There was no significant difference between the rates of fixation in the unamended and sewage sludge plots. Additional perturbation experiments suggested that nitrogen addition indirectly stimulates nitrogen fixation by enhancing Spartina production and root exudation. Glucose additions, on the other hand, suppressed nitrogen fixation on a long-term basis. It is suggested that the microbial population in the soil out-competed the plants for the available nitrogen and in turn suppressed plant production and possibly root exudation. A comparison of nitrogen fixation in clipped and unclipped Spartina plots substantiated the suggestion that root exudation probably supports nitrogen fixation. Fixation in the clipped plots was significantly lower (P < 0.05) than the rates in the unclipped plots.

Journal Article↗
PubMedDate not supplied

[The deamination of L-arginine and the synthesis of active nitrogen compounds in Yersinia pestis].

Y. pestis were found to be capable of highly effective deamination of L-arginine with the formation of citrulline and the synthesis of active nitrogen compounds. The formation of citrulline by the cells of initial strains and arginine-dependent derivatives with the blocking of the synthesis of arginine on the level of ArgG, ArgF and ArgE was shown. The temperature of incubation, the concentration of hydrogen ions (pH) and the presence of exogenic L-arginine were found to produce a regulatory effect on the intensity of the process of deamination. The products of arginine decomposition are supposed to play a pathogenetic role in Y. pestis infection.

Arginine↗
PubMed2002

Effect of ambient temperature on losses of volatile nitrogen compounds from stored laying hen manure.

Eight one tonne lots of laying hen manure were stored in individual, environmentally controlled chambers for 18-weeks at one of four constant temperatures: 12, 15, 20 and 25 degrees C. The losses of volatile nitrogen compounds, ammonia, and changes in dry matter and pH were measured during the storage period. There was a linear (P < 0.001) loss of nitrogen from the manure over the 18-week storage period. This loss represented approximately 60% of the initial nitrogen present in the manure. The rate of nitrogen loss increased non-linearly (P < 0.05) with increasing storage temperature. Poultry housing systems that provide low temperature storage of manure are recommended to reduce the volatile nitrogen losses from egg-laying enterprises.

Animals↗
PubMed2001

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.

Biomass↗
PubMed1964

BIOCHEMICAL CHANGES DURING THE GROWTH OF FUNGI. I. NITROGEN COMPOUNDS AND CARBOHYDRATE CHANGES IN PENICILLIUM ATROVENETUM.

Gottlieb, David (University of Illinois, Urbana), and James L. Van Etten. Biochemical changes during the growth of fungi. I. Nitrogen compounds and carbohydrate changes in Penicillium atrovenetum. J. Bacteriol. 88:114-121. 1964.-Changes in the biochemical constituents of cells were studied during the growth and development of Penicillium atrovenetum. Growth of the fungus, as measured by the dry weight, could be divided into four phases: lag, log, stationary, and death. The percentages of total nitrogen, cold trichloroacetic acid-soluble nitrogen, ribonucleic acid (RNA), and protein increased to a maximum during the lag phase, and subsequently decreased as the fungus aged. The percentage of deoxyribonucleic acid (DNA) was always slightly higher in the spores than in the mycelium. The DNA in the mycelium decreased in the lag phase, and then increased slightly to a plateau for the duration of the log phase, followed by a decrease to a constant percentage during the stationary and death phases. Carbohydrates were present in higher concentration in the mycelium than in the spores. The percentage of carbohydrates in the mycelium increased continually until it reached a maximum late in the log phase, and then decreased as the fungus entered the death phase. The results reported for this fungus are, in general, in agreement with those reported for other microorganisms. Namely, the percentages of enzyme-forming compounds, such as amino acids, nucleotides, RNA, and protein, were highest in the lag phase, whereas storage compounds such as carbohydrates increased to a maximum near the end of the log phase. The definition of log phase in fungi depends on the criteria that are used. If, instead of using the linear increase in dry weight to delimit this growth period, one uses the end of net protein, RNA, and DNA synthesis, a more realistic concept of growth emerges.

Biochemical Phenomena↗
PubMed1998

[Determination of copper, zinc, iron and calcium in wheat and maize and three nitrogen compounds in high and low risk areas of esophageal cancer].

This study reports the concentrations of copper, zinc, iron and calcium in wheat and maize from high risk area Linzhou and low risk area Yuzhou of esophageal cancer and three nitrogen compounds of four types of drinking water in Linzhou. The results showed that the concentrations of zinc and calcium in wheat and maize from Linzhou were significantly lower than these from Yuzhou, the copper concentrations in grains were higher and the iron in maize was lower. The nitrate-N concentrations in four types of drinking water from Linzhou were below the national standard but the nitrite and NH3-N concentrations were higher than the national limits. The results suggest that the low concentrations of zinc, iron and calcium and high concentrations of copper in grains as well as the high concentrations of nitrite and NH3-N may be related to the etiology of esophageal cancer.

Calcium↗
PubMedDate not supplied

[Excretion of nitrogen compounds in sweat during a sauna].

The aim of the study was to determine a loss of nitrogen compounds with sweat in sauna and to estimate their plasma concentration. Sweat was collided during 30 min stay in sauna. Blood was taken before and immediately after the sauna. Concentrations of ammonia, urea, creatinine and uric acid were determined in the both fluids. It has been found, that the concentration of ammonia in sweat exceeds, that in plasma by 77 times. Ammonia plasma concentration following sauna increased by about 60%. Sweat urea concentration exceeded that in plasma by 3.5 times. Plasma urea concentration was significantly reduced after sauna. Sweat creatinine concentration was about two times higher than that in plasma. No uric acid was detected in sweat. Sweating did not affect plasma creatinine and uric acid concentrations. Results indicate that considerable amount of nitrogen is lost with sweat during sauna.

Adult↗
PubMed1993

[Do soluble organic nitrogen compounds cause unusual algal blooms in seawater?].

Up to now the nature and importance of the macromolecular forms of organic nitrogen in the marine environment is poorly understood. There is no doubt on the capacity of phytoplankton to utilize low molecule weight dissolved organic nitrogen compounds competitively with bacteria. In marine ecosystems the members of the plankton community show a complex close coupling with biological substances. In spite of trace concentrations the high dynamics in uptake and release processes cause strong fluxes of these compounds. In the case of inorganic nutrient deprivation or reduced photosynthesis under light deficiency algal utilization of organic nitrogen becomes noteworthy. Even under high nitrate supply an algal development occurred which was mainly triggered by amino acid uptake as was demonstrated during field experiments in the German Bight. The consumption of amino acids is controlled by several uptake systems, which are specified for transportation of different groups of amino acids through the cell wall. Since the uptake systems can also differ among species, the amino acid composition of the environment could preferentially enhance the growth of some selected species in comparison with other components of natural phytoplankton assembles. In the scope of increasing water pollution and the resulting shift in nutrient distribution one may expect the development of phytoplankton species, which had not been supported so far. In estuaries and costal zones photosynthesis is effected by light absorbance from particulate material. This phenomenon additionally will sustain algae, which are able to compensate a photosynthesis deficit by heterotrophic uptake. Though interrelationships are not clear up to now, it becomes evident that increasing impact of dissolved organic substances cause strong changes in species composition of marine ecosystems.

Amines↗