in this study the effect of nitrogen form and different oxygen levels on growth and development and macronutrients concentrations in lettuce plants was investigated. this investigation showed that sole ammonium application caused fresh and dry weight reduction of shoot and root in lettuce plant. but different oxygen levels had no effect on them. nitrogen concentration of shoot was higher in amm...

Voltage-clamp studies on intact and internally perfused squid giant axons demonstrate that ammonium can substitute partially for either sodium or potassium. Ammonium carries the early transient current with 0.3 times the permeability of sodium and it carries the delayed current with 0.3 times the potassium permeability. The conductance changes observed in voltage clamp show approximately the sa...

One of the challenges to be confronted during landfill operations is to handle the landfill leachate with high ammonium content. Current biological ammonium removal processes either are complicated and hard to manage, or require major investments. Low cost and low maintenance onsite systems for the treatment of landfill leachate with high ammonium content are in urgent need, especially for land...

Increased ammonium (NH(4)(+)/NH(3)) in the brain is a significant factor in the pathophysiology of hepatic encephalopathy, which involves altered glutamatergic neurotransmission. In glial cell cultures and brain slices, glutamate uptake either decreases or increases following acute ammonium exposure but the factors responsible for the opposing effects are unknown. Excitatory amino acid transpor...

Formaldehyde gas, generated by the depolymerization of paraformaldehyde and in the presence of water vapor, has been traditionally used for biological decontamination of equipment and spaces utilized for research with a susceptible biological agent. This gas has often been neutralized with ammonia gas, generated by the thermal decomposition of ammonium bicarbonate or ammonium carbonate. An elem...

Evidence is presented that intracellular ammonium is trapped in vacuoles of maize (Zea mays L.) root tips because of rapid movement of ammonia between cytoplasm and vacuoles. The concentration of cytoplasmic ammonium is estimated to be <15 mum at extracellular ammonium concentrations up to 1 mm. The implications for pathways of ammonium assimilation are discussed.

The causal role of ammonium in hepatic encephalopathy was identified in 1930s. Astroglial cells are primary cellular elements of hepatic encephalopathy which conceptually, can be considered a toxic astrogliopathology. Previously we have reported that acute exposure to ammonium activated ouabain/Na,K-ATPase signalling pathway, which includes Src, EGF receptor, Raf, Ras, MEK and ERK1/2. Chronic i...

In R. capsulatus synthesis and activity of the molybdenum and the alternative nitrogenase is controlled at three levels by the environmental factors ammonium, molybdenum, light, and oxygen. At the first level, transcription of the nifA1, nifA2, and anfA genes--which encode the transcriptional activators of all other nif and anf genes, respectively--is controlled by the Ntr system in dependence ...

To the editor: The case report by Tuchscherer and Rehman is indeed interesting. However, this article requires that we look more closely at what is meant by urinary ammonium being measured. The renal response to metabolic acidosis is to increase excretion of hydrogen ion in the form of ammonium; the measurement of its urinary concentration is important when trying to identify the cause of the a...