The discovery of ammonia-oxidizing archaea (AOA), now generally recognized to exert primary control over ammonia oxidation in terrestrial, marine, and geothermal habitats, necessitates a reassessment of the nitrogen cycle. In particular, the unusually high affinity of marine and terrestrial AOA for ammonia indicates that this group may determine the oxidation state of nitrogen available to asso...

This study was conducted to investigate the effects of different levels of peptide supplementation on rumen fermentation pattern, digestibility and microbial protein synthesis. Three rumen-cannulated Holstein dairy cows were used in a 3 × 3 Latin square experiment within 21 days period. The ruminal infusion of sodium caseinate (CN) was 0 (control), 50 and 100 g/d. Dry matter intake, milk yield ...

Ammonia is an important component of the nitrogen cycle and because it is oxidized in the environment by microorganisms (i.e., nitrification), it is a large source of available nitrogen in the environment (Raven & Johnson 1989). The complexity of the nitrogen cycle, various rate determining environmental conditions for nitrification (e.g., pH, temperature), and the physical behaviour of ammonia...

Abstract In the zero-water exchange shrimp culture pond maintained with application of indigenous bioaugmentor, low levels total ammonia–nitrogen were reported, indicating relevance microbial communities. Sediments (0–5 cm layer) sampled from (85th day) and bacterial archaeal communities; specifically, ammonia oxidizers (ammonia-oxidizing bacteria, ammonia-oxidizing archaea, anaerobic bacteria)...

background: in the recent years, eutrophication has become a serious challenge for many of the water ecosystems. it has affected the environmental and economical aspects of the anzali wetland, which is known as one of the significant ecosystem. due to the increase of the nutrient loadings from the industrial, agricultural and human activities, the wetland’s health is faced many serious problems...

Reducing dietary protein content in fish feeds will reduce cost of production if growth performance can be maintained. In this study, we assessed the effects of reduced dietary protein content from 33.5% to 27.4% with ideal amino acids profile on the growth, immune parameters, intestinal microvilli length and total ammonia nitrogen discharge of tilapia. After 8 weeks of feeding, growth performa...

Sevhtrriia rliizobiuni strain ORS57 1. which grows in the free-living state at the expense of N, or ammonia. requires nicotinic acid as a growth factor and also uses this vitamin as a nitrogen source in culture medium devoid of ammonia. Consequently, under nitrogen-fixing conditions, Sesbania rhizohiw1 requires about 10-times more nicotinic acid than when grown in the presence of ammonia. The p...

Nitrogen is an essential element for many biological processes, including those occurring in plants (Ogura et al., 2006). Despite the abundance of atmospheric nitrogen, production of nitrogen fertilisers by the Harber–Bosch process is increasing annually due to the deficiency of ammonia produced by biological nitrogen fixation—the enzyme-catalyzed reduction of nitrogen gas (N2). Concern over ‘g...

Carcinus maenas and Necora puber were exposed to air for 72 h and 18 h, respectively, at 18 degreesC. Nitrogen excretion, blood and muscle ammonia content and blood urate and lactate content were recorded throughout the experimental emersion and following reimmersion (recovery period). During emersion, the rate of ammonia excretion was strongly reduced in both species, while urea and amine excr...

We have used genetic methods in Methanococcus maripaludis to study nitrogen metabolism and its regulation. We present evidence for a "nitrogen regulon" in Methanococcus and Methanobacterium species containing genes of nitrogen metabolism that are regulated coordinately at the transcriptional level via a common repressor binding site sequence, or operator. The implied mechanism for regulation re...