Metabolic acidosis is associated with poor outcomes in CKD. Because impaired renal ammonium excretion is important in the pathogenesis of acidosis, urine ammonium excretion might be a better and perhaps earlier acid-base indicator of risk than serum bicarbonate, particularly in patients without acidosis. We evaluated the association between baseline ammonium excretion and clinical outcomes in A...

The transport of ammonia by various tissues throughout the body is of fundamental importance for nitrogen excretion in invertebrates, yet sites and mechanisms of ammonia transport are not presently well understood. In this thesis a novel ammonium-selective microelectrode was developed using the crown ether ionophore TD19C6, which is approximately 3800-fold more selective for NH 4 + than Na + co...

in order to study the effects of ph and the ratio of nitrate to ammonium in nutrient solution, on the growth characteristics and on the yield of spinach (spinacia oleracea l.), a factorial experiment was conducted consisting of two factors including: nutrient solution ph in three levels (4.5, 6.5 and 8) and nitrate to ammonium ratio of nutrient solution in five levels (100:0, 75:25, 50:50, 25:7...

A mmonium (NH 4 +), the substance created by the fi xation of atmospheric nitrogen (N 2), occupies a central role in cellular nitrogen metabolism. However, even though it is an important metabolite, free ammonium is present only transiently in biological systems, where it is rapidly converted into amino acids—initially glutamate and, particularly, glutamine. From there, transamination reactions...

The AMMONIUM TRANSPORTER (AMT) family comprises six isoforms in Arabidopsis thaliana. Here, we describe the complete functional organization of root-expressed AMTs for high-affinity ammonium uptake. High-affinity influx of (15)N-labeled ammonium in two transposon-tagged amt1;2 lines was reduced by 18 to 26% compared with wild-type plants. Enrichment of the AMT1;2 protein in the plasma membrane ...