Showing papers on "Ammonia published in 1971"

Changes of Some Mitochondrial Enzyme Activities of Cucumber Leaves during Ammonium Toxicity

Abstract: The following enzyme activities were determined in the mitochondria of cucumber leaves (Cucumis sativus L. cv. Suisei No. 2) during ammonium toxicity: malate dehydrogenase, succinate dehydrogenase, glutamate dehydrogenase, cytochrome c oxidase, NADH diaphorase, NADH oxidase, succinate: cytochrome c oxidoreductase, NADH: cytochrome c oxidoreductase and adenosine triphosphatase. The activities of all enzymes except ATPase increased more or less during ammonium toxicity. Generally speaking the marked increase was found at 7 days treatment with 200 mg/1 NH3-N. The adenosine triphosphatase activity of injured plants was lower than that of normal plants through treatment. The addition of various organic acids (15 mM) to the culture solution contaning 200 mg/1 NH3-N (14.3 mM NH4Cl) suppressed the ammonium toxicity. The accumulation of free ammonia in the leaves was also repressed by the addition of organic acids. The results of present and previous reports suggest that the increase of respiratory metabolism due to ammonium toxicity is required for the supply of organic acids, specially δ-ketoglutaric acid, to counteract ammonia. Uncoupling in mitochondria resulting in the increase of respiration does not seem to occur during ammonium toxicity.

Studies on the ecology of actinomycetes in soil III. The behaviour of neutrophilic streptomycetes in acid soil

Abstract: Streptomycetes which occurred in soil with a pH below that which permitted growth in pure culture were studied. The distribution of the dominant species in the acidic A1 horizon of a podzol was investigated. Its response to various soil amendments was followed and shown to be related to changes in soil pH caused by ammonia release. Differential ammonia adsorption by organic particles in the acid sandy soil was detected. Fungi were the most efficient initial decomposers of nitrogenous substrates added to acid soil but after release of ammonia, Streptomycetes became active. It was suggested that occasional periods of activity by neutrophilic Streptomycetes in acid soil occur in microsites of ammonia adsorption on organic fragments. This was demonstrated in model systems.

Effect of Ammonia and Nitrate on Growth, Photosynthesis, and Ribulosediphosphate Carboxylase Content of Dunaliella tertiolecta

Abstract: When the marine Chlorophycean flagellate Dunaliella tertiolecta Butcher was grown with short photoperiods of bright light, the use of ammonia rather than nitrate as a nitrogen source led to a 30 % reduction of the doubling time of cell matter. The cell cycle (onset of light to completion of cell division) was shortened by about 10% only. Ammonia-grown cells possessed a greater capacity for photosynthetic oxygen evolution at light saturation than did nitrate-grown cells; their content of ribulosediphosphate carboxylase was likewise greater. The faster growth of Dunaliella tertiolecta with ammonia may be partly a consequence of a general increase in net protein synthesis resulting in a greater content of photosynthetic enzymes.

Hereditary Metabolic Disorders of the Urea Cycle

Abstract: Publisher Summary Urea is the main end product of nitrogen metabolism. It is formed from the ammonia arising from the metabolism of the amino acids of protein by a sequence of five reactions, four of which comprise the urea cycle proper. The end result is the conversion of ammonia into urea, with the reformation of the individual reactants of the cycle. Compared with other metabolic pathways, the urea cycle is short, possibly the shortest of all. Defects of the enzymes mediating all four reactions of the urea cycle proper have now been established, and there is some evidence of the existence of a fifth enzyme defect, involving carbamyl phosphate synthetase, mediating the initial reaction of the pathway. One of the most important results of a defect of the biosynthesis of urea is an increased level of blood ammonia. Therefore, it is essential to consider other conditions that might affect indirectly the urea cycle or in some other way raise the blood ammonia. Because lysine can act as a competitive inhibitor of the conversion of arginine to ornithine and urea, an increased level of plasma lysine may therefore inhibit the urea cycle.

System for removing nitrogen oxide from automotive exhaust

Abstract: A PROCESS FOR REMOVING CARBON MONXIDE, HYDROCARBONS AND NITROGEN OXIDES FROM THE EXHAUST STREAM OF INTERNAL COMBUSTION ENGINES BY PASSING T HE EXHAUST GAS THROUGH A CATALYST FOR CONVERSION OF CO TO CARBON DIOXIDE AND NITROGEN OXIDES TO AMMONIA, FOLLOWED BY ADMIXING THE EFFLUENT FROM THE CATALYST WITH A SECOND EXHAUST GAS STREAM DILUTED WITH AIR, AND PASSING THIS COMBINED EFFLUENT THROUGH A SECOND CATALYTIC CONVERTOR, W HEREIN THE AMMONIA AND NITROGEN OXIDES REACT TO FORM NITROGEN, AND THE CO AND HYDROCARBONS ARE CONVERTED TO INNOCUOUS ENTITIES.

Infra-red study of hydrogen chloride adsorption on rutile surfaces

Abstract: The adsorption of hydrogen chloride on outgassed, deuterated, and reduced rutile surfaces has been studied by infra-red spectroscopy. Surface Ti4+O2–Ti4+ groups react with hydrogen chloride to form hydroxide ions and chloride ions on adjacent titanium ion sites. The reaction of hydrogen chloride with surface hydroxide ions leads to water coordinately bound to Ti4+ and associated with a chloride ion. Rearrangement to Ti4+Cl– species occurs and leads to the formation of adsorbed water which can react with hydrogen chloride to form H3O+Cl– on the surface. The adsorption of hydrogen chloride leads to surface species which act as Bronsted acid sites in the presence of adsorbed ammonia or pyridine.

Regulation of photoreduction in Rhodospirillum rubrum by ammonia

Abstract: Rhodospirillum rubrum was grown in a malate medium without bound nitrogen anaerobically under N2. 1. Resting cells of these cultures showed a gradual decrease in photoreducing activity (light-induced consumption of CO2 with H2). Small amounts of ammonium chloride immediately restored the initial activity. 2. A stoichiometric relationship was found between the amount of ammonium chloride added and the amount of gases which disappeared during the ensuing photoreduction: 8 H2 and 4 CO2 were taken up per mole NH3. 3. Addition of l-malate under photoreducing conditions (=atmosphere of 4% CO2 in H2) led to a substrate dependent gas evolution of H2 and CO2. Simultaneous addition of l-malate and various amounts of ammonium chloride gave at first only a comparatively small gas evolution which levelled off into a plateau. 4. The subsequent gas exchange following this first step depended upon the ratio of l-malate to NH4Cl. Titration of l-malate revealed that 2.2±0.3 moles of malate were consumed per mole of ammonium chloride. If there were more than 2.2 moles of malate present per mole of ammonium chloride, gas evolution was resumed after a characteristic time interval. If, on the other hand, there was less malate available, a strong gas uptake, photoreduction, was initiated. 5. In the presence of NH4Cl, malate was metabolized about 3 times faster than in its absence. 6. These observations are discussed in regard to the interrelationships between photosynthetic CO2 reduction, nitrogen fixation and protein metabolism of R. rubrum.

The response of normal subjects to the short ammonium chloride test: the modifying influence of renal ammonia production.

Abstract: 1. The response to the short ammonium chloride acidification procedure in seventeen normal young men was carefully defined by performing this test with rigid control. 2. Wide variation in the response was observed, emphasizing the difficulty of interpretation of small changes when using this procedure. 3. After ingestion of ammonium chloride, urine pH correlated positively with both net acid and ammonium excretion contrary to present concepts. It is suggested that the renal capacity to produce ammonia dictates the relation of urine pH to net acid and ammonium excretion, respectively.

Nitrification inhibitors and ammonia volatilization

Abstract: A nitrification inhibitor applied with ammonium sulphate to bare soil and to grass increased the persistence of ammonium-N in soil and decreased the amount of nitrate-N leached from bare soil. Ammonia was volatilized more rapidly from bare soils treated with ammonium sulphate plus the inhibitor than when ammonium sulphate alone was used; the inhibitor increased the amount of ammonia volatilized from grass covered soils eight times.

Process for ammonia manufacture

Abstract: ORGANIC PHYSICAL SOLVENT REMOVAL OF CARBON DIOXIDE AND OTHER ACID GASES IS ECONOMIC IN AMMONIA MANUFACTURING WHERE THE SHIFT REACTOR EFFLUENT CONTAINING THE ACID GASES AND EXCESS HEAT IS INDIRECTLY HEAT EXCHANGED WITH A CLOSED ABSORPTION REFRIGERATION CYCLE USED TO SUPPLY REFRIGERATION FOR AMMONIA PRODUCTION, IN LIEU OF MECHANICAL COMPRESSION FOR REFRIGERATION.

Deposition of copper

Abstract: Copper powders or coatings are deposited by contacting with a reducing gas, e.g., hydrogen or carbon-monoxide, a liquid organic medium containing copper in a compound of or in association with at least one tertiary carboxylic acid having at least five carbon atoms to cause precipitation of copper from the organic phase, a base, preferably ammonia, being present in solution in the organic medium during precipitation.