increasing the concentration of ammonia in water can cause fish death. this study was conducted to compare the performance of conditioned activated carbon and zeolite in ammonia (tan = total ammonia nitrogen) removal in a simulated transport of rainbow trout fry in 40-liter plastic bags. hence, responses of zeolite and conditioned activated carbon in ammonia (tan) removal at different concentra...

an aquaculture system can be a potentially significant source of antibacterial compounds and ammonia in an aquatic environment. in this study, the removal of total ammonia nitrogen and florfenicol antibiotic from synthetic aqueous wastewater was assessed by applying a commercial tfc (thin film composite) polyamide nanofilter. the effects of ph (6.5-8.5), pressure (4-10 bar), concentration of to...

Growth of Saccharomyces cerevisiae on ammonia and glutamine decreases the expression of many nitrogen catabolic genes to low levels. To discriminate between ammonia- and glutamine-driven repression of GAP1, PUT4, GDH1 and GLN1, a gln1-37 mutant was used. This mutant is not able to convert ammonia into glutamine. Glutamine-limited continuous cultures were used to completely derepress the express...

The nitrogen cycle describes the processes through which nitrogen is converted between its various chemical forms. These transformations involve both biological and abiotic redox processes. The principal processes involved in the nitrogen cycle are nitrogen fixation, nitrification, nitrate assimilation, respiratory reduction of nitrate to ammonia, anaerobic ammonia oxidation (anammox) and denit...

Short term (2-hour) incorporation of nitrogen from nitrate, glutamine, or asparagine was studied by supplying them as unlabeled ((14)N) tracers to growing pea (Pisum sativum L.) leaves, which were previously labeled with (15)N, and then following the elimination of (15)N from various amino components of the tissue. Most components had active and inactive pools. Ammonia produced from nitrate was...

Ammonia nitrogen wastewater (about 100 mg/L) was treated by two-stage ozone oxidation method. The effects of ozone flow rate and initial pH on ammonia removal were studied, and the mechanism of ammonia nitrogen removal by ozone oxidation was discussed. After the primary stage of ozone oxidation, the ammonia removal efficiency reached 59.32% and pH decreased to 6.63 under conditions of 1 L/min o...

Clues to the mechanism of biological nitrogen fixation have been sought through experiments aimed at defining the substances specifically required by organisms to effect the process. The nitrogen-fixing sequence in bacteria is known to proceed through ammonia (Zelitch et al., 1951; Newton et al., 1953; Wilson and Burris, 1953; Virtanen, 1953). Thus, the effect of adding ammonium salts to a fixi...

Cheviot wethers were defaunated by using dioctyl sodium sulfosuccinate and were constantly infused with urea to provide 2.87% of the daily N intake. Defaunation resulted in higher rumen dry matter and lower rumen pH. The molar per cent propionate was higher in defaunated sheep, whereas the molar per cent butyrate and acetate was lower. Apparent nitrogen digestibility, nitrogen utilization, and ...

Addition of ammonium salts to E. coli cells grown on a medium with glutamate as the sole nitrogen source is followed by rapid inactivation of glutamine synthetase (GS) I1 The active form of the enzyme (GSa) and the inactive form (GSb) have been isolated.2 Both forms behave similarly in the analytical ultracentrifuge, electrophoresis, and ion exchange chromatography. 2 In a cell-free system GSa ...

Studies in which (15)N-labeled precursors of urinary ammonia were infused into the artery of an intact functioning kidney of an acidotic dog have led to the following conclusions: Preformed ammonia and ammonia derived from the amide nitrogen of plasma glutamine are added directly to urine without significant incorporation into amino acid intermediates of renal tissue. Thus, reductive amination ...