Effect Of Ammonium Ions Research Articles

Inhibiting Effect of Ammonium Ion in Protoplast Culture of Some Asteraceae Plants

Inhibiting Effect of Ammonium Ion in Protoplast Culture of Some Asteraceae Plants

Effect of ammonium ion on coenzyme Q10 fermentation by Agrobacterium species.

Effect of ammonium ion on coenzyme Q10 fermentation by Agrobacterium species.

Effect of ammonium ion, inorganic phosphate and amino acids on the biosynthesis of protylonolide, a precursor of tylosin aglycone.

The production of tylosin by Streptomyces fradiae KA-427 in a defined medium was inhibited by ammonium ions and by inorganic phosphate. The production of protylonolide, an early lactonic intermediate of tylosin biosynthesis with the same carbon skeleton as tylosin aglycone, by a mutant of strain KA-427 was also reduced by these two kinds of ions. In contrast, the bioconversion of protylonolide to tylosin by another mutant was less susceptible to ammonium ions but was sensitive to inorganic phosphate. The addition of protylonolide to a culture of S. fradiae KA-427 increased the tylosin yield, suggesting that aglycone synthesis is limiting under the conditions used. When L-valine, L-leucine, L-isoleucine, L-threonine, or the corresponding 2-keto acid was added to the culture medium, the protylonolide titer increased. The addition of [14C]valine gave rise to [14C]protylonolide. 13C NMR spectroscopic analysis revealed that iso-butyrate, which is a valine metabolite, was incorporated into protylonolide at the carbons known to originate from propionate and n-butyrate. Taking account of these findings, the regulation of tylosin biosynthesis in S. fradiae by ammonium ion is discussed in relation to amino acid metabolism.

Effect of inhibitors on nitrogenase regulation in the cyanobacterium Nostoc linckia

Summary The effects of ammonium ion and certain inhibitors of protein synthesis on nitrogenase activity in Nostoc linckia were compared during heterocyst induction and exponential phases. Early stages of heterocyst differentiation and nitrogenase induction are prone to ammonium inhibition. Nitrogenase activity continued to increase even in presence of ammonium in 36 h old cultures. Addition of ammonium chloride in exponential, nitrogen-dependent cultures had little effect on nitrogenase activity up to 16 h whereafter the activity fell. The heterocyst frequency was higher in rifampicin and lower in chloramphenicol, as compared to control cultures.

The Release and Neosynthesis of Glutamic Acid Are Increased in Experimental Models of Hepatic Encephalopathy

The effects of ammonium ions on the release of glutamic acid from the rat cerebral cortex were measured in vivo using cortical cups and a multiple ion detection technique. The neosynthesis of this amino acid from glucose was also studied in two experimental models of hepatic encephalopathy: (1) rats receiving large amounts of ammonium acetate (i.p.) and (2) rats with a surgically constructed portocaval anastomosis. Intraperitoneal administration of 8 mmol/kg of ammonium acetate increased the cortical release of glutamic acid from 9.1 +/- 0.8 to 19 +/- 2 (nmol X cm-2 X min-1). Moreover, 20 min after ammonium acetate administration the rate of incorporation of 13C2, originating from [13C]glucose, into glutamic acid increased by 65%. In several brain areas of rats bearing a portocaval anastomosis and fed ad libitum for 4 weeks, the content of glutamic acid slightly increased and the rate of formation of [13C2]glutamate from [13C]glucose approximately doubled. These results indicate that ammonium ions increase the release and the formation of glutamic acid in the brain. The resulting increased concentration of this amino acid in the extracellular spaces may be one of the mechanisms of ammonia toxicity in vivo.

Effect of ammonium ions on the aerobic glycolysis in Ehrlich ascites tumor cells

The effect of ammonium ions on aerobic glycolysis has been studied in Ehrlich ascites tumor cells. The inhibition of respiration caused by 5-25 mM glucose, fructose or mannose is increased by the presence of 0.5-20 mM NH4+. Under these conditions, more glucose is used and a crossover analysis of intermediate metabolites of glycolysis indicates an increase in the glycolytic flux. In spite of the stimulation of glycolysis, the production of lactate decreases in the presence of ammonium ions, although the concentration of free alanine (glutamate and aspartate) is increased. Ammonium ions enhance the oxidation of cytochromes c and a caused by glucose, and decrease the adenine nucleotide pool and the ATP/ADP ratio. These effects of ammonium ions are observed when glucose is present in the incubation medium, and do not occur when only ammonium salts were supplied to the cells metabolizing endogenous substrates.

Conductometric titration of nitrate by formation of the silver—1,10-phenanthroline—nitrate ternary complex

Nitrate forms an insoluble ternary complex, Ag(phen) 2NO 3, with silver in the presence of 1,10-phenanthroline (phen). A simple and direct conductometric titration of nitrate, based on the formation of this ternary complex, has been investigated. The sample solution is adjusted to pH 4.3 with acetate buffer and titrated with 0.1 M Ag(phen) + 2 complex solution in 40% ethanol—water mixture. The relative error is less than 0.5% and relative standard deviation less than 0.4%. The effect of ammonium ion and urea has also been studied. The method has been successfully applied to determination of nitrate-nitrogen in fertilizer.

Effects of low ammonia levels on NAD(P)H levels and glutamate secretion during calcium‐dependent depolarization of CNS slices

Simultaneously with an evoked release of endogenous glutamate, redox changes in NAD(P)H levels occur as a response to electrical or chemical stimulation of the isolated CNS tissue. While electrical-field stimulation induces a transient increase in tissue NAD(P)H, KCl stimulation produces a decrease in NAD(P)H. One possible interpretation for this difference is that elevated KCl induced glutamate release from larger cell populations, including glia, while electrical stimulation might have a more neuro-specific action. In the present report, it is shown that the electrically or biochemically evoked release of endogenous glutamate is strongly inhibited by ammonium ions at 3--5 mM in the hippocampus and frontal cortex. At the same time, ammonium ions inverted the NAD(P)H response of the tissue during electrical stimulation, making both electrical and KCl depolarization induce a decrease in NAD(P)H. There was no effect of ammonium ions per se on the NAD(P)H levels, and to obtain the effects on both NAD(P)H and glutamate release, the tissue had to be exposed for 40--60 minutes to ammonium ions. The results are interpreted to indicate that ammonium ions influence regulatory control mechanisms in cell populations in the tissue slice that secretes glutamate in response to depolarization.

Effects of ammonium ions on endplate channels.

Miniature endplate currents, recorded from voltage-clamped toad sartorius muscle fibers in solutions containing ammonium ions substituted for sodium ions, were increased in amplitude and decayed exponentially with a slower time constant than in control (Na) solution. The peak conductance of miniature endplate currents was also greater in ammonium solutions. The acetylcholine null potential was -2.8 +/- 0.8 mV in control solution, and shifted to 0.9 +/- 1.6 mV in solutions in which NH4Cl replaced half the NaCl. In solutions containing NH4Cl substituted for all the NaCl, the null potential was 6.5 +/- 1.3 mV. Single channel conductance and average channel lifetime were both increased in solutions containing ammonium ions. The exponential relationship between the time constant of decay of miniature endplate currents or channel lifetime and membrane potential was unchanged in ammonium solutions. A slight but consistent increase in peak conductance during miniature endplate currents and single channel conductance was seen as membrane potential became more positive (depolarized) in both control and ammonium solutions. Net charge transfer was greater in ammonium solutions than in control solution, whether measured during a miniature endplate current or through a single channel. The results presented here are consistent with an endplate channel model containing high field strength, neutral sites.

The effects of ammonium ions and chloroquine on uptake and degradation of 125I-labeled asialo-fetuin in isolated rat hepatocytes

The effects of NH 4 + and chloroquine on the uptake, the degradation and the intracellular distribution of 125I-labeled asialo-fetuin in isolated rat hepatocytes were investigated. Both ammonium ions and chloroquine inhibited asialo-fetuin degradation; chloroquine in high concentrations reduced uptake as well. Both compounds reduced the equilibrium density of the lysosomes in sucrose gradients. Labeled asialo-fetuin did not seem to accumulate in the lysosomes of cells exposed to NH 4 + or chloroquine. The possibility that both compounds retard the fusion between lysosomes and phagosomes is discussed.

Water uptake and trans-potential in sunflower roots as influenced by ammonium ions

SummaryThe effect of ammonium ions on artificially imposed water flux and trans-root potential difference was studied in excised sunflower roots. Water movement through the root system decreased and the potential of the xylem sap became less negative with respect to the external medium as the ammonium ion concentration in the external medium increased. It is suggested that ammonium ions appeared to inhibit water uptake either wholly or partially through a general or specific blockage of root metabolism which reflected on the permeability of water through root membranes. The reduction in the trans-root potential was due to the effect of ammonium ions on the original trans-root potential of epidermal root cells. This may indicate that the site of water uptake inhibition lies within the root epidermis.

Effects of Ammonium Ions, Oxygen, Carbon Monoxide, and Acetylene on Anaerobic and Aerobic Hydrogen Formation by Anabaena cylindrica B629

An investigation was made of various factors, both experimental and physiological, which influenced the formation of hydrogen gas by the heterocystous cyanobacterium Anabaena cylindrica B629 when incubated in both argon and air. A. cylindrica B629 produces hydrogen in air in the presence of carbon monoxide, acetylene, or both, with a short lag period. The rate of production in air at optimal concentrations of these compounds was found to be comparable with that in an argon atmosphere. Whereas under argon, ammonium ions (0.5 to 6 mM) were found to inhibit hydrogen formation in a manner which was dependent on light intensity and not relieved by oxygen (1 to 20% of gas phase), in air-carbon monoxide-acetylene, these ions (up to at least 0.5 mM) slightly stimulated hydrogen production for at least 24 h. Conclusions are drawn about short-term aerobic and anaerobic hydrogen formation by A. cylindrica B629 and the effects of ammonium ions, oxygen, carbon monoxide, and acetylene on these processes.

Effect of ammonium ions on activity of hydrolytic enzymes during sporulation of yeast

The addition of 10 mM ammonium sulfate to sporulation medium noncoordinately blocked the increases in protease C, protease B, alpha-mannosidase, and 1,4-amyloglucosidase activities which occur during normal sporulation of Saccharomyces cerevisiae, but had only a minor effect on the 10-fold increase in alkaline phosphatase activity.

The effect of ammonium ions on uptake of glutamine and other amino compounds by cultured cells of rapeseed

Nitrogen starvation for 24 h, particularly NH 4 (+) deprivation, of cultured repeseed (Brassica napus L.) cells caused them to develop the potential for a rapid increase in the rate of uptake of several amino compounds. Time-course studies, primarily using [(14)C]glutamine, showed that the increase in uptake rate continued for about 10 h after the 24-h N-starvation period. Addition of 2 mM NH 4 (+) to N-starved cells caused the increase in glutamin-uptake rate to cease, and the rate began to fall after 3-6 h to the level observed in cells grown continuously in the presence of NH 4 (+) . Neither pH changes in the medium caused by the presence of NH 4 (+) nor the competitive inhibition by NH 4 (+) of glutamine transport into the cells were responsible for the changes in the glutamine uptake rate. Similar results were obtained in time-course studies with [(14)]leucine.

Effects of ammonium ions on spontaneous action potentials and on contents of sodium, potassium, ammonium and chloride ions in brain in vitro.

Abstract—The effects of ammonium ions on the frequency of spontaneous action potentials in guinea‐pig cerebellar slices, recorded with an extracellular microelectrode, and on the contents of sodium, potassium and chloride ions in incubated guinea‐pig cerebellar, and rat brain cortex, slices have been investigated. The frequencies of the spontaneous action potentials are partially suppressed by concentrations of NH4Cl less than 2 mm and completely abolished by concentrations exceeding 2 mm. The amplitudes of the spike discharges are unaffected. A lag period of at least 15 s precedes the inhibition. The suppressing action of NH on the spike frequency is reversible, as shown by complete recovery on removal of NH after short time intervals. Deficiency of Cl− in the superfusion medium causes conversion of inhibition by NH to excitation. Reduction of [K+], or of [Na+], causes increase of inhibition by NH in a normal [Cl1], and reduction of excitation in a low [Cl1], medium. The inhibitory effects of NH on spike frequency are unaffected by picrotoxin or strychnine. NH4Cl, even at 1 or 2 mm, causes a significant increase of aerobic glycolysis. It is suggested that the lag period preceding the suppression of the frequency of spike discharges by NH is partly due to a metabolic change induced by NH, perhaps a transient lowering of pH in the responsible neurons, causing changed permeability to Cl− and possibly to K+ and Na+, NH promotes, in guinea‐pig cerebellar slices, an inward flow of Na+ and an outward flow of K+, the latter being greater than that due to exchange of K+ for NH. NH4Cl at 1 or 2 mm causes an outward flow of K+ and an inward flow of Cl− in rat brain cortex slices. The movement of Cl− is biphasic, the first phase, seen with low [NH], consisting of an increase of tissue content of Cl− with little or no fluid uptake and a second phase, seen with high (> 5 mm) concentrations of NH, in which the uptake of Cl− is directly proportional to the fluid uptake. It is suggested that the first phase is largely neuronal in location whilst the second is largely glial. In infant rat brain cortex slices, there seems to be predominantly an equal exchange of NH for K+. There is little evidence of energy assisted concentrative uptake of NH by brain slices and this is thought to be due largely to the rapid diffusion of undissociated NH3 across cell membranes. It is suggested that some NH (amounting to about 2 mequiv/1) may be bound in the brain. It is concluded that changes in ionic permeabilities, particularly that of Cl−, partly due to a metabolic action, may be responsible for some of the acute cerebral effects of NH administration.

Inhibition of meiosis in Saccharomyces cerevisiae by ammonium ions: Interference of ammonia with protein metabolism

Meiosis and sporogenesis in yeast are completely blocked by ammonia added in low concentration (10 mM) to the sporulation medium. Premeiotic DNA synthesis is not initiated in the presence of ammonium ions. The inhibitor interferes with protein turnover by reducing both synthesis and breakdown. The in vitro activities of proteinases A and B in sporulation medium supplemented with ammonia are much lower than in the control. This may partially explain the effect of ammonium ions on protein metabolism in vivo.

Effect of ammonium ions on the induction of nitrite reductase in Neurospora crassa.

Results with strain am-la, a glutamate dehydrogenaseless mutant, showed that ammonium ions must first be metabolized in order to repress nitrite reductase in Neurospora.

Activation of pyruvate dehydrogenase during metabolism of ammonium ions in hemoglobin-free perfused rat liver.

1 Ammonium chloride addition to perfused rat liver results in a shift of the steady state of the pyruvate dehydrogenase system towards the active (dephospho) form. This is evidenced by direct measurement of enzyme activity in freeze-stopped liver tissue, by net uptake of pyruvate from the perfusate, and also by an increased release of labeled CO2 from [1-14C]pyruvate. Half-maximal concentration of NH4Cl for extra pyruvate uptake is 0.5–0.7 mM. The effect is readily reversible. 2 Extra urea formation upon ammonia addition is matched by an extra O2 uptake as that required theoretically for the two ATP-consuming steps of urea synthesis. At 1.5 mM NH4Cl, there is no significant difference of ATP levels compared to the controls. 3 When extra urea formation and the concomitant O2 uptake are suppressed due to limitation at carbamoylphosphate synthesis in carbon-dioxide-free media, the activation of pyruvate dehydrogenase by NH4Cl is still observed. 4 When ammonia is generated intracellularly from glutamine, an extra uptake of pyruvate is not observed. 5 The NH4Cl-induced activation of pyruvate dehydrogenase is increased in presence of acetoacetate, and decreased in presence of 3-hydroxybutyrate. 6 Possible mechanisms are discussed. While some of the observations could also be explained by a direct interaction of ammonium ions with the pyruvate dehydrogenase interconversion system, the effect of ammonium ions on pyruvate dehydrogenase is interpreted to be mediated in an indirect manner by changes of the mitochondrial concentration of 2-oxoglutarate. As 2-oxoglutarate decreases during reductive amination to glutamate, a pool of high-energy compounds (eg. GTP or related substances) dependent upon 2-oxoglutarate oxidation is depleted, resulting in a de-inhibition of pyruvate dehydrogenase by the interconversion system. The detailed mechanism of the linkage between 2-oxoglutarate oxidation and pyruvate oxidation remains to be elucidated.

Effect of Ammonium Ion in Seawater on Dissolution of Plant Materials of Seawater Distillatio

Effect of Ammonium Ion in Seawater on Dissolution of Plant Materials of Seawater Distillatio

Effect of ammonium ions on the polarographic behavior of nitriles and amides of some pyridinecarboxylic acids

The character of the polarographic reduction of picolinonitrile, nicotinonitrile, isonicotinonitrile, isocinchomeronic acid dinitrile, picolinamide, and nicotinamide on a dropping mercury electrode with a buffer-solution base electrolyte in the presence of ammonium ions depends on the concentration of the ammonium ions, which interact with the ring nitrogen.