The transport physiology of the urinary bladder of both the freshwater rainbow trout (Oncorhychus mykiss) and the marine gulf toadfish (Opsanus beta) was characterized with respect to urea, and the suitability of the urinary bladder as a model for renal urea handling was investigated. Through the use of the in vitro urinary bladder sac preparation urea handling was characterized under control c...

The possible presence of a urea transporter in the kidney of the gulf toadfish (Opsanus beta) and further characterization of the pulsatile facilitated transporter previously identified in its gills were investigated by comparing the extra-renal and renal handling of two urea analogues with the handling of urea. Toadfish were fitted with caudal artery and indwelling urinary ureteral catheters a...

Nitrification inhibitors may be potential management strategy to reduce N2O emissions in irrigated rice (Oryza sativa L.). A field experiment was conducted to evaluate chemically synthesized as well as locally available neem plant products on N2O emissions, from an irrigated rice at New Delhi, India. Emission of nitrous oxide (N2O) was monitored during 70 days by closed chamber method in rice (...

Urea is ubiquitously used as a protein denaturant. To study the structure and energetics of aqueous urea solutions, we have carried out molecular dynamics simulations for a wide range of urea concentrations and temperatures. The hydrogen bonds between urea and water were found to be significantly weaker than those between water molecules, which drives urea self-aggregation due to the hydrophobi...

To study the renal medullary transport and accumulation of urea in dogs independent of water transport, we obliterated the medullary electrolyte gradient by a sustained ethacrynic acid diuresis. Infusions of urea were also given at various rates to vary urinary urea concentration. In the steady state, the kidneys were removed, and slices were analyzed for water, urea, and electrolytes. In every...

We examined whether populations of Drosophila melanogaster could evolve a genetically based tolerance to high levels of toxic compounds (urea or ammonia) added to their larval food medium. We also examined whether tolerance to one compound may impart cross-tolerance to other compounds. Five populations selected for ammonia tolerance (AX), five populations selected for urea tolerance (UX), and f...

Many organisms endure extended periods of dormancy by depressing their metabolism, which effectively prolongs the use of their endogenous energy stores. Though the mechanisms of hypometabolism are varied and incompletely understood, recent work suggests that urea accumulation in autumn and early winter contributes to reduced metabolism of hibernating wood frogs (Rana sylvatica). Urea accumulati...

To evaluate the effects of treating or supplementing common reed (Phragmites australis) with 2% urea on intake, nutrient apparent digestibility, and blood metabolites, fifteen Baluchi rams (35.4±2.3 kg body weight) were used in a completely randomized design. Treatments were as follows: 1) common reed, 2) common reed supplemented with 2% urea solution at feeding, and 3) common reed tre...

T HE experiments presented here show that the rate of urea formation is accelerated in rats during the first 24 hours after removal of three quarters or all of the total renal tissue, and that the greater the amount of kidney excised the greater is the quantity of urea formed. The observations were made on rats in which urea formation from food protein was excluded by subsistence on a calorical...