Nectar-feeding birds have remarkably low nitrogen requirements. These may be due either to adaptation to a low-protein diet or simply to feeding on a fluid diet that minimizes metabolic fecal nitrogen losses. We measured minimal nitrogen requirements (MNR) and total endogenous nitrogen loss (TENL) in the omnivorous European starling Sturnus vulgaris, fed on an artificial nectar-like fluid diet ...

Escherichia coli contains two PII-like signal trans-duction proteins, PII and GlnK, involved in nitrogen assimilation. We examined the roles of PII and GlnK in controlling expression of glnALG, glnK and nac during the transition from growth on ammonia to nitrogen starvation and vice versa. The PII protein exclusively controlled glnALG expression in cells adapted to growth on ammonia, but was un...

The study was designed to determine urinary excretions of endogenous total, urea, ammonia and creatinine nitrogen in adult domestic cats. Endogenous urinary nitrogen metabolite excretions were determined by feeding adult cats a protein-free diet for 10 d or by regression to zero protein intake of the urinary nitrogen metabolite excretions of adult cats fed four levels of dietary protein. The me...

Inorganic nitrogen is commonly found in three different forms: Ammonia (NH4), nitrite (NO2), and nitrate (NO3). Ammonia is a principle form of nitrogen found in urban wastewater and runoff especially from pastures and feedlots. According to Kadlec and Knight (1996), ammonia, or ammonium nitrogen, is the preferred nutrient form for most wetland plants because of its importance in plant growth. A...

WHEN the collection of faeces during a metabolic experiment extends over a considerable period of time, difficulties arise in the determination of the total nitrogen and sulphur contents. Sampling of the wet composite specimen is generally unsatisfactory and ordinary methods of drying on a steam-bath result in a considerable loss of both nitrogen (as ammonia) and sulphur (mainly as sulphide). I...

Coastal aquaculture can contribute to eutrophication of receiving waters. New technologies and improved management practices allow the aquaculture industry to be more sustainable and economically viable. Current practices, however, do not provide an additional use for effluent water. Nitrogen, phosphorus and other effluent compounds could be valuable plant nutrients. Inflow and effluent water f...

Novel approaches to efficient ammonia synthesis at an ambient pressure are actively sought out so as to reduce the cost of ammonia production and to allow for compact production facilities. It is accepted that the key is the development of a high-performance catalyst that significantly enhances dissociation of the nitrogen-nitrogen triple bond, which is generally considered a rate-determining s...

Ammonia-nitrogen #ux (NH -N"(14/17)NH ) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred during the fall of 1998 through the early spring of 1999, and each lagoon was examined for approximately one week. Analysis of #ux variation was made with respect to lagoon surface water tem...

A study was conducted to evaluate the correlation between selected physico-chemical parameters of water and their effects on growth of Rainbow trout (Oncorhynchus mykiss) in raceway system in the area of Sarab Gerdu, Iran. The samples were collected from twenty raceways (270- day old fish, surface area 55m2 flow rate 150 ls-1 total production 15 T). Physico-chemical parameters were the fluctuat...

Changes in the fractions of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in two laboratory-scale reactors were investigated using 16S rRNA probe hybridizations. The reactors were operated in intermittent aeration mode and different aeration cycles to treat anaerobically digested swine wastewater with ammonia concentrations up to 175 mg NH(3)-N/L. High ammonia removals (>98.8%) were...