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PubMed1976

Thin-layer chromatography of homopyrimidazole derivatives.

The chromatographic behaviour of 14 homopyrimidazole derivatives has been studied on thin layers of silica gel, aluminium oxide and ammonia-saturated silica gel. The relationships between structure and chromatographic behaviour, as well as the most suitable systems for separating the individual derivatives, are discussed on the basis of RF values. The delta RMg values, showing the effect on the polarity, are given for certain functional groups.

Aluminum↗
PubMed1983

Methodology for recovery of chemically treated Staphylococcus aureus with neutralizing medium.

Recovery results of Staphylococcus aureus ATCC 6538 treated with phenolics and quaternary ammonium compounds on Dey and Engley (D/E) neutralizing medium at various time intervals were compared by the use of two commonly used media. Two recovery processes were utilized. In one, the chemically treated organisms were plated directly onto an agar medium. In the other, the aliquot was first put in broth and then was plated with agar. By either process, the numbers and the time period for recovery of organism were greater on D/E medium.

Ammonia↗
PubMedDate not supplied

Review of the decontamination of aflatoxins by ammoniation: current status and regulation.

Ammoniation of corn, peanuts, cottonseed, and meals to alter the toxic and carcinogenic effects of aflatoxin contamination has been the subject of intense research effort by scientists in various government agencies and universities, both in the United States and abroad. Results of these studies have been well documented over the last 20 years. Engineers have devised workable systems of treatment of whole seeds, kernels, or meals; chemists have identified and characterized products formed from the reaction of aflatoxin B1 with ammonia with and without a meal matrix; biochemists have studied the biological effects of these compounds in model systems; and nutritionists have studied animal responses to rations containing ammoniated or non-ammoniated components. This review describes these studies. Results demonstrate overwhelming support for the efficacy and safety of ammoniation as a practical solution to aflatoxin detoxification in animal feeds.

Aflatoxins↗
PubMed1994

Mutational analysis of the NH4+-nitrogen controls that regulate ammonium transport activity, heterocyst differentiation, nitrogenase activity and the heterocyst-spacing pattern in the cyanobacterium Nostoc muscorum.

Mutational analysis of the genetic determinants mediating NH(4+)-nitrogen regulating effects on NH(4+)-transport activity, heterocyst differentiation, nitrogenase activity and heterocyst pattern formation was carried out in Nostoc muscorum. Evidence suggested the operation of three separate genetic determinants in such nitrogen control; one mediating NH(4+)-repression control on both heterocyst formation and NH(4+)-transport activity, a second (Nif-R) mediating NH(4+)-repression control on nitrogenase synthesis/activity and a third (Pat-R) essential for intercalary heterocyst formation/distribution. Ammonia itself functioned as repressor signal of heterocyst formation and nitrogenase synthesis/activity and the glutamine synthetase enzyme played no role in the repression/derepression control of heterocyst development and functional nitrogenase formation.

Bacterial Proteins↗
PubMed1989

Ornithine aminotransferase activity, liver ornithine concentration and acute ammonia intoxication.

5-Fluoromethylornithine (5FMOrn) is a specific inactivator of L-ornithine:2-oxoacid aminotransferase (OAT). Inactivation of OAT causes the enhancement of L-ornithine (Orn) concentrations in all tissues. Intraperitoneal or oral administration of 10-50 mg/kg of 5FMOrn per day to albino mice rendered partial protection against lethal intoxication with 26 mmol/kg of ammonium acetate. The protective effect was maximal around 16 h after 5FMOrn administration, at the time when endogenous Orn concentrations were maximal. At this time protection by 5FMOrn against acute ammonia intoxication was comparable to that observed 1 h after the intraperitoneal administration of 10 mmol/kg of L-arginine. Pretreatment with 5FMOrn prevented the enhancement of excessive urinary excretion of orotic acid by ammonia intoxicated mice, and it enhanced urea formation in the liver. These biochemical effects demonstrate that 5FMOrn shifts Orn into the urea cycle, Orn which normally would be transaminated. Since even long-term treatment of mice with 5FMOrn did not reveal toxic effects, this compound may be considered for the treatment of certain conditional deficiencies of Orn or arginine.

Acetates↗
PubMed2004

Flow-injection analysis with fluorescence detection for the determination of trace levels of ammonium in seawater.

A method using flow-injection, gas-diffusion, derivatisation and then fluorescent detection has been established for ammonium ion determination in seawater. The fluorescent derivative formed by reacting ortho-phthaldialdehyde (OPA) and sulfite with ammonia gives high sensitivity while removing potential interferences. This is required to measure the low concentrations of ammonium often seen in the open ocean. The experimental conditions (flow-rate, reagent concentrations, membrane configurations, etc.) were manipulated to improve performance. For a sample throughput of 30 samples h(-1), the limit of detection was 7 nM, the coefficient of variation was 5.7% at 800 nM, and the calibration curve was linear to at least 4 micromol L(-1). Interferences were minimised by a gaseous diffusion step. Volatile small molecular-weight amines as interferents were discriminated against by this method. They neither passed through the membrane as efficiently as ammonia, nor reacted as readily with OPA when sulfite was the reductant. Contamination by ammonia from laboratory and shipboard sources complicates application of the method to natural waters, especially measurement of low concentrations (<100 nM) in open-ocean waters. Steps to overcome contamination are described in detail. Some results are presented for ammonium determination in Southern Ocean and Huon Estuary (Tasmania) waters.

Amines↗
PubMed1994

Effects of peptone on hybridoma growth and monoclonal antibody formation.

Hybridoma WuT3 secreting a monoclonal antibody against T lymphocytes was grown in RPMI 1640 medium supplemented with 1% human serum. The effect of the concentration of peptone, as an additive, was investigated on cell growth, monoclonal antibody formation, and cell metabolism over 0-10 g l-1 range. It was found that 1-5 g l-1 peptone can significantly promote the growth of cells and increase the formation of monoclonal antibody, especially at 3-5 g l-1, when both the accumulating level and secretion rate of monoclonal antibody are higher than that at other peptone concentrations. Based on glucose, lactate and ammonia analysis data, the efficiency of glycolysis was assessed and the utilization of amino acids was more efficient at 3-5 g l-1 peptone. The cell growth and monoclonal antibody formation were inhibited at higher peptone concentrations, e.g. 10 g l-1.

Amino Acids↗
PubMed1978

The response of Bobwhite quail chicks to dietary ammonium and an antibiotic-vitamin supplement when fed B1 aflatoxin.

Dietary ammonium phosphate and a water soluble antibiotic-vitamin supplement were tested as possible means of preventing or minimizing the effects of aflatoxin in the diet of Bobwhite quail chicks. Aflatoxin (B1) was added to the diet at levels of 0, 0.4 and .8 ppm in Experiment 1 and 0, .8 and 1.2 ppm in Experiment 2. In addition, ammonium phosphate was included in the diet at levels of 0 or 1.46% and an antibiotic-vitamin supplement was added to the drinking water at 0 or 600 mg/liter. All treatments were given from 1 to 32 days of age in Experiment 1 and 1 to 28 days of age in Experiment 2. The addition of aflatoxin to the diet resulted in decreased body weight, feed consumption and percent tibia ash, increased mortality and increased feed required per unit of body weight. The addition of ammonia to the diet in the form of monoammonium phosphate did not alleviate the effects of aflatoxin. Water supplementation with an antibiotic-vitamin mixture improved weight and feed efficiency and decreased mortality of chicks receiving aflatoxin.

Aflatoxins↗
PubMed2005

Design, synthesis, and activity of analogues of phosphinothricin as inhibitors of glutamine synthetase.

A new group of potent inhibitors of glutamine synthetase was designed and synthesized. The X-ray structure of bacterial glutamine synthetase complexed with phosphinothricin was used for computer-aided structure-based design of the inhibitors, in which the methyl group of phosphinothricin was chosen as the modification site. Amino and hydroxyl moieties were introduced into the phosphinic acid portion of the lead molecule to interact with ammonium binding site in the active cleft of the enzyme. Designed compounds were synthesized in enantiomerically pure form analogous to l-glutamic acid. In vitro kinetic studies with Escherichia coli glutamine synthetase confirmed the biological activity of the designed inhibitors, which with K(i) values in the micromolar range (K(i) = 0.59 microM for the most potent compound 2) appear to be slightly weaker inhibitors or equipotent to phosphinothricin.

Aminobutyrates↗
PubMed1993

Proliferation of human colonic mucosa as an intermediate biomarker of carcinogenesis: effects of butyrate, deoxycholate, calcium, ammonia, and pH.

A high-fat/high-protein diet has been reported to promote colon cancer by increasing luminal bile acid and ammonia concentrations, whereas butyrate, calcium, and low colonic pH may have protective effects. In this study, bromodeoxyuridine labeling of colonic epithelium was investigated after incubating biopsies from the ascending colon of 70 patients with HCl (20 mM, pH 6.0), butyric acid (H-BUT, 20 mM, pH 6.0), sodium butyrate (Na-BUT, 10 mM, pH 8.0), CaCl2 (10 mM), calcium butyrate (Ca-BUT, 10 mM), ammonium butyrate (NH4-BUT, 10 mM), deoxycholic acid (DCA, 5 microM), and a combination of DCA and Na-BUT (DCA/Na-BUT, 5 microM/10 mM). Compared to NaCl, H-BUT and Na-BUT increased the whole crypt-labeling index significantly, whereas HCl and CaCl2 had no effect. Reduced labeling, however, occurred with Ca-BUT in comparison to equimolar Na-BUT. No differences in the labeling indexes were found for NH4-BUT compared to Na-BUT, but increased labeling with expansion of the proliferative zone to the upper 40% of the crypt was seen with DCA compared to NaCl. DCA-induced hyperproliferation was abolished by coincubation with DCA/Na-BUT. These data suggest that butyrate, calcium, and DCA have complex influences on mucosal proliferation. Since luminal concentrations of these compounds are influenced by dietary interventions, the findings of this study may be of particular interest with regard to colon cancer development and prevention.

Adult↗
PubMed2003

Determination of nickel with 2-(2-quinolylazo)-5-diethylaminoaniline as a chromogenic reagent.

A sensitive, selective and rapid method for the determination of nickel based on a rapid reaction of nickel(II) with 2-(2-quinolylazo)-5-diethylaminoaniline (QADEAA) has been developed. In the presence of pH = 6.0 ammonia-ammonium chloride buffer solution and sodium dodecyl sulfonate (SDS) medium, QADEAA reacts with nickel to form a violet complex having a molar ratio of 1:2 (nickel to QADEAA). The molar absorptivity of the complex is 1.38 x 10(5) l mol(-1) cm(-1) at 595 nm. Beer's law is obeyed in the range of 0.01-0.4 microg/ml. This method had been applied to the determination of nickel with good results.

Chromogenic Compounds↗
PubMed2003

New concepts of microbial treatment processes for the nitrogen removal in wastewater.

Many countries strive to reduce the emissions of nitrogen compounds (ammonia, nitrate, NOx) to the surface waters and the atmosphere. Since mainstream domestic wastewater treatment systems are usually already overloaded with ammonia, a dedicated nitrogen removal from concentrated secondary or industrial wastewaters is often more cost-effective than the disposal of such wastes to domestic wastewater treatment. The cost-effectiveness of separate treatment has increased dramatically in the past few years, since several processes for the biological removal of ammonia from concentrated waste streams have become available. Here, we review those processes that make use of new concepts in microbiology: partial nitrification, nitrifier denitrification and anaerobic ammonia oxidation (the anammox process). These processes target the removal of ammonia from gases, and ammonium-bicarbonate from concentrated wastewaters (i.e. sludge liquor and landfill leachate). The review addresses the microbiology, its consequences for their application, the current status regarding application, and the future developments.

Industrial Microbiology↗
PubMed1993

Effect of dietary protein and urea on in vitro caecal ammonia production from urea and uric acid in cockerels.

1. Single Comb White Leghorn adult cockerels were fed on 50 g/kg protein diet, 200 g/kg protein diet or 50 g/kg protein diet plus urea and in vitro ammoniagenesis from urea and uric acid in the caeca was determined. 2. Four-fold protein intake caused about 4.6-fold increase in caecal ammonia production from urea (P < 0.05), and tended to increase it from uric acid as compared with 50 g/kg protein-fed birds. 3. Dietary urea significantly increased caecal ammonia production from urea and uric acid by about 2 and 3 times as much as those of control birds, respectively (P < 0.05). 4. It is concluded that increased protein intake and the feeding of urea are able to induce ammoniagenesis from urea and uric acid in the caeca of fowls.

Animals↗
PubMed1997

Impact of trichloroethylene and toluene on nitrogen cycling in soil.

The effects of trichloroethylene (TCE) and toluene on soil nitrogen-cycling activities were examined. Ammonium oxidation potential (AOP) was reduced after incubation with as little as 1 microgram of TCE ml-1, and the effects were generally greater when toluene was present and increased with longer exposure. Arginine ammonification potential and denitrification enzyme activity were constant regardless of TCE concentration or the presence of toluene, while nitrite oxidation potential (NOP) exhibited variable sensitivity. KCl-extractable ammonium levels increased dramatically after exposure to 30 and 60 micrograms of TCE ml-1 in the presence of toluene, whereas gamma-irradiated or sodium azide-treated soil incubated with the same concentrations of TCE and toluene showed no increase. Alfalfa-amended soils showed similar decreases in AOP and increases in extractable ammonium during incubation with 60 micrograms of TCE ml-1 and 20 micrograms of toluene ml-1, although most probable number estimates of the ammonium oxidizer population showed no difference between exposed and unexposed soil. AOP and extractable ammonium returned slowly to control levels after 28 days of incubation in the presence of TCE and toluene. Activity assays to which various TCE and toluene concentrations were added indicated that AOP and NOP were relatively more sensitive to these compounds than was arginine ammonification potential. These results indicate that the soil microbial populations responsible for nitrogen cycling exhibit different sensitivities to TCE and toluene and that they may be more susceptible to adverse effects than previously thought.

Ammonia↗
PubMed2001

Nitrogen isotope ratios in pine bark as an indicator of N emissions from anthropogenic sources.

The article describes the use of Scots pine bark to identify nitrogen sources in eastern Germany, as well as background areas in Russia and Bulgaria, by using natural isotope ratios of total nitrogen (Nt) and individual N compounds such as ammonium (NH4+), nitrate (NO3-) and amid nitrogen (amide-N). The samples collected were analysed using an elemental analyser in connection with a gas isotope mass spectrometer (EA-IRMS). Natural 15N abundances in pine bark from impact areas suggest that the ammonium accumulated on the surface of the bark is released from livestock management. Bark of Scots pines growing near agricultural land had highly depleted delta15Nt values (between -8 and -12 one thousand percent), while bark from background areas (unpolluted areas) displayed slightly negative delta15Nt values (mean 15Nt = -3.8 one thousand percent). It is assumed that part of the N adsorbed on the bark surface is mainly derived from ammonia (mean 15Nt = -40.3 one thousand percent) escaping from livestock housing and during the application of manure. This assumption is confirmed by experiments under controlled conditions in which manure samples were spread on soil. In addition, temporal and spatial variations of 15Nt abundances in pine bark from various locations in eastern Germany as well as pine stands in Nature Park Dübener Heath are discussed.

Agriculture↗
PubMed1986

Uptake, intracellular transport and release of 125I-poly(vinylpyrrolidone) and [14C]-sucrose-asialofetuin in rat liver parenchymal cells. Effects of ammonia on the intracellular transport.

We have studied the intracellular transport of 125I-labeled poly(vinylpyrrolidone) (125I-PVP) and [14C]sucrose-asialofetuin (14C-SAF) in isolated rat hepatocytes. 125I-PVP and 14C-SAF are taken up in the cells by fluid phase and receptor-mediated endocytosis, respectively. The labeled degradation products formed from 14C-SAF are trapped in the lysosomes. They can therefore serve as markers for lysosomes in subcellular fractionation studies. The accumulation of 125I-PVP in the cells was rapid initially and then decreased to a constant value. The diminished rate of accumulation was due to release (exocytosis) of previously endocytosed 125I-PVP. The release of 125I-PVP was studied in cells that had accumulated 125I-PVP for various times and then after washing incubated in new medium at 37 degrees. About 25% of the radioactivity associated with the cells after 1 hr was released to the medium subsequently. No such release was observed in cells that had taken up 14C-SAF. Subcellular distribution of 125I-PVP and 14C-SAF was studied by isopycnic centrifugation in sucrose gradients. Both compounds were sequentially associated with light (1.13 g/ml) and dense (1.19 g/ml) vesicles. Exocytosed 125I-PVP was derived from the light vesicles. The denser organelles were probably lysosomes as their distribution coincided with that of lysosomal enzymes. By measuring radioactivity soluble and precipitable in trichloroacetic acid it could be shown that only degraded 14C-SAF was associated with lysosomes. Undegraded 14C-SAF was associated with vesicles banding at 1.13 g/ml. Degraded 14C-SAF was, however, also seen first in this region of the gradient, suggesting that degradation started in a light lysosome. Both uptake and release of 125I-PVP were temperature dependent; both processes ceased at 10 degrees. Ammonium ions had negligible effects on uptake and release of 125I-PVP. The amine inhibited, however, the transfer of both 125I-PVP and 14C-SAF to the lysosomes.

Acetylglucosaminidase↗
PubMed1985

Amidation of, and (R)-1-amino-2-propanol attachment to, the corrin ring during vitamin B-12 biosynthesis by Clostridium tetanomorphum extracts.

Two intermediate stages in cobalamin biosynthesis, amidation of carboxylic acid groups in the corrin ring and (R)-1-amino-2-propanol attachment at propionic acid position f, have been studied using cell-free extracts from the obligate anaerobe Clostridium tetanomorphum. The preparation of an incomplete corrinoid, probably cobinic acid-a,c,d,e,g-pentaamide, as an in vitro amidation substrate was accomplished via mild acid hydrolysis of cobinamide. Weak, but reproducible activities for both amidation and (R)-1-amino-2-propanol attachment were found in crude, nucleic acid-free and DE-52 column-purified protein fractions. The amidation reaction was glutamine-dependent in crude fractions, but became ammonium ion-dependent in more purified fractions. Significant problems encountered were (a) the weak and unstable character of both enzyme activities, and (b) the irreversible changes in the visible spectra of the incomplete corrinoids employed as substrates caused by use of thiol-reducing agents in the buffers and assays.

Amides↗
PubMed2003

Temporal and spatial expression of ammonium transporter genes during growth and development of Dictyostelium discoideum.

Ammonia is an important signaling molecule involved in the regulation of development in Dictyostelium. During aggregation, ammonia gradients are established, and the ammonia concentration in the immediate environment or within a particular cell throughout development may vary. This is due to the rate of cellular ammonia production, its rate of loss by evaporation to the atmosphere or by diffusion into the substratum, and perhaps to cellular transport by ammonium transporters (AMTs). Recent efforts in genome and cDNA sequencing have identified three ammonium transporters in Dictyostelium. In addition to physically altering the levels of ammonia within cells, AMTs also may play a role in ammonia signaling. As an initial step in identifying such a function, the temporal and spatial expression of the three amt genes is examined. RT-PCR demonstrates that each of the three amt mRNAs is present and relatively constant throughout growth and development. The spatial expression of these three amt genes is examined during multiple stages of Dictyostelium development using in situ hybridization. A distinct and dynamic pattern of expression is seen for the three genes. In general, amtA is expressed heavily in pre-stalk cells in a dynamic way, while amtB and amtC are expressed in pre-spore regions consistently throughout development. AmtC also is expressed in the most anterior tip of fingers and slugs, corresponding to cells that mediate ammonia's effect on the choice between slug migration and culmination. Indeed, amtC null cells have a slugger phenotype, suggesting AmtC functions in the signaling pathway underlying the mechanics of this choice.

Amino Acid Sequence↗