Absorption of ammonia from the gastrointestinal tract results in problems that range from hepatic encephalopathy in humans to poor nitrogen efficiency of cattle with consequences for the global climate. Previous studies on epithelia and cells from the native ruminal epithelium suggest functional involvement of the bovine homologue of TRPV3 (bTRPV3) in ruminal NH4+ transport. Since the conductan...

ACTIVE REABSORPTION of Na across the thick ascending limb of Henle (TALH) plays an essential role in the urine concentrating mechanism, as it generates and maintains the axial osmolality gradient in the outer medulla. Na enters the TALH cell mostly through apical Na -K -2Cl (NKCC2) cotransporters, to a lesser extent through Na /H (NHE3) exchangers, and it is extruded at the basolateral membrane...

A self-design bioreactor system employing a fixed bed operation process with immobilized Bacillus subtilis AYC beads for NH4+-N removal from slightly polluted water was proposed. Polyvinyl alcohol and Na-alginate were used as a gel matrix to entrap Bacillus subtilis AYC to form the immobilized beads. The NH4+-N removal process was studied in a intermittent operation mode to examine the start-up...

An optimization algorithm was used to compute parameter values for kinetic models of NH4 transport by the renal Na-K-2Cl cotransporter (NKCC2) and K-Cl cotransporter (KCC). The optimization method finds model off-binding and translocation rate constants by minimizing the difference between model unidirectional fluxes and published data on NH4 -dependent 86Rb+ uptake by the NKCC and KCC transpor...

Yeast alpha-isopropylmalate isomerase was found to be markedly stabilized by high concentrations of glycerol and (NH4)2SO4. Such conditions of high ionic strength inhibited the enzyme, stabilized the enzyme to heat, and affected kinetic parameters. The isomerase was found to exhibit ionic strength-dependent hysteresis when enzyme, totally but reversibly inhibited by storage under conditions of ...

We compared gross N fluxes by N pool dilution in a coarse-textured agricultural soil when N was applied to the soil NH4 C pool by either: (i) mixing a NH4NO3 solution into disturbed soil or (ii) injection of NH3 gas into intact soil cores. The two techniques produced similar results for gross N mineralization rates indicating that NH4 C production in soil was not altered by soil disturbance, me...

The swamp eel, Monopterus albus, can survive in high concentrations of ammonia (>75 mmol l(-1)) and accumulate ammonia to high concentrations in its brain (4.5 µmol g(-1)). Na(+)/K(+)-ATPase (Nka) is an essential transporter in brain cells, and since NH4(+) can substitute for K(+) to activate Nka, we hypothesized that the brain of M. albus expressed multiple forms of Nka α-subunits, some of whi...