Spectrophotometric Determination of Ammonia as Indophenol

Bolleter, W. T.; Bushman, C. J.; Tidwell, P. W.

doi:10.1021/ac60172a034

Cited by 403 publications

(189 citation statements)

References 7 publications

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“…Protein overexpression was induced with 2 mM isopropyl 1-thio-␤-D-galactopyranoside and maintained for 6 h; the overexpressed protein in the crude protein fraction obtained from the periplasmic fraction was further purified. We chose KGM, SM, and 3-PPN for assay of the enzymatic activity of hNit2/-amidase (11,23,31). The proteins were then subjected to kinetic analysis.…”

Section: Methodsmentioning

confidence: 99%

Structural Insights into the Catalytic Active Site and Activity of Human Nit2/ω-Amidase

Chien

Gao²,

Cooper

et al. 2012

Journal of Biological Chemistry

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Background: Human Nit2/-amidase is a putative tumor suppressor. Results: Both the catalytic triad and loop 116 -128 of hNit2 play an essential role in the enzyme-substrate binding and enzymatic activity. Conclusion:The results of MD simulations are consistent with the kinetic analysis obtained with substrates ␣-ketoglutaramate and succinamate. Significance: This work provides the basis for new areas of research into tumor glutamine metabolism and hyperammonemic diseases.

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Section: Methodsmentioning

confidence: 99%

Structural Insights into the Catalytic Active Site and Activity of Human Nit2/ω-Amidase

Chien

Gao²,

Cooper

et al. 2012

Journal of Biological Chemistry

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“…Samples were filtered, frozen and brought to the laboratory. Here, concentrations of NH + 4 (mg dm −3 ) was obtained measuring the absorbance at 625 nm obtained by reaction with phenol and hypochlorite in order to give an intensely blue solution of the so formed indophenols (Bolleter et al, 1961); NO − 2 (mg dm −3 ) was evaluated by spectrophotometric measurement at 543 nm of colored derivative obtained from reaction with p-aminobenzene sulphonamide and N-(1-naphtil)-etylendiamine (APHA, 1998); NO − 3 (mg dm −3 ) concentration were measured at 220 nm with a correction for organic matter absorbance (Armstrong, 1963); finally, in order to obtain PO 3− 4 (mg dm −3 ) concentrations, samples were allowed to react with a composite reagent containing molybdic acid, ascorbic acid, and trivalent antimony. The resulting complex polyacid is reduced to give a blue solution with the maximum extinction measured at 885 nm (Strickland and Parsons, 1972).…”

Section: Physical and Chemical Parametersmentioning

confidence: 99%

Seasonal and multi-annual patterns ofPhragmites australisdecomposition in a wetland of the Adriatic area (Northeast Italy): a three-years analysis

Bertoli

Brichese

Michielin

et al. 2016

Knowl. Manag. Aquat. Ecosyst.

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-Wetlands are one of the most biologically productive ecosystems, in which reedbeds of Phragmites australis are an essentially detritus-based system where litter decomposition is a fundamental process. This study represents a three year dataset describing cyclic trends of Phragmites australis leaf litter breakdown in a temporary and managed environment. For three years, 45 days field experiments were seasonally performed, using leaf bag technique within a large managed temporary pond (Natural Reserve of the Isonzo River Mouth, Northeast Italy), in order to analyze spatial and temporal variation in decomposition processes, to search for patterns on seasonal and inter-annual time scale and to infer the relevance of the main environmental features (physical and chemical) on decomposition dynamic. During the three years of analysis, decay rates (k) ranges were 0.0066-0.0075 days −1 in autumn, 0.0108-0.0158 days −1 in spring and k = 0.0168 days −1 in summer. Average mass loss per day % range was 0.97-1.31% in autumn, 1.12-2.04% in spring and 1.79-2.06% in summer. A well-defined seasonal cycle was observed through the study years as result of the drought-reflooding dynamic and the highest percentage (91.1%) of the average mass loss per day % variability was explained above all by rainfall, temperature and conductivity. Key-words:Leaf bag / wetland / seasonal dynamic / temporary pond / decomposition rate Résumé -Schémas saisonnier et pluriannuel de décomposition de Phragmites australis dans une zone humide de la région adriatique (Italie du Nord) : une étude de trois ans. Les zones humides sont parmi les écosystèmes les plus productifs, dont les roselières à Phragmites australis constituent un système basé essentiellement sur les détritus, où la décomposition de la litière représente un processus fondamental. Cette étude analyse un ensemble pluriannuel de données qui décrit les tendances cycliques relatives à la décomposition de Phragmites australis dans un milieu temporaire d'eau douce sujet à la gestion. Pendant trois ans, 45 jours d'expériences sur le terrain ont été effectués de façon saisonnière, en utilisant la technique du sac de feuilles dans un grand étang temporaire géré (Réserve Naturelle de l'embouchure de la rivière Isonzo, Italie du Nord), afin d'analyser les variations spatiales et temporelles dans les processus de décomposition, à la recherche de modèles à l'échelle temporelle saisonnière et inter-annuelle et d'en déduire la pertinence des principales caractéristiques environnementales (physiques et chimiques) sur la dynamique de la décomposition. Au cours des trois années d'analyse, les taux de décomposition (k) étaient 0,0066-0,0075 jours −1 à l'automne, 0,0108-0,0158 jours −1 au printemps et k = 0,0168 jours −1 en été. La perte moyenne de masse par jour était de 0,97 à 1,31 % en automne, 01,12 à 02,04 % au printemps et de 1,79 à 2,06 % en été. Un cycle saisonnier bien défini a été observé au cours des années d'études résultant de l'alternance assec-mise en eau. Le pourcentage le plus élevé (...

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“…Prior to determination of rumen ammonia-N concentration, rumen fluid was shaken and then centrifuged (2600g for 12 min) to obtain a clear supernatant. After a reaction, which converts ammonia to form an indophenol dye (Bolleter et al 1961), spectrophotometric determination was conducted on an Olympus AU400 clinical analyser. Digesta samples were analysed for Yb using a Varian 220FS Atomic Absorption Spectrometer with a nitrous oxide/acetylene flame and emission detection.…”

Section: Analytical Proceduresmentioning

confidence: 99%

Ruminal protein degradability of a range of tropical pastures

Bowen

Poppi

McLennan³

2008

Aust. J. Exp. Agric.

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Abstract. The rumen degradability parameters of the diet selected by two to four oesophageal-fistulated Brahman steers grazing a range of tropical pastures were determined by incubation of extrusa in nylon bags suspended in the rumen of rumen-fistulated (RF) Brahman steers. The effective protein degradability (Edg) was determined by measuring the rate of disappearance of neutral detergent insoluble nitrogen (NDIN) less acid detergent insoluble nitrogen (ADIN) in the incubated extrusa. Six to eight RF steers also grazed each of the pastures along with the oesophageal-fistulated steers, to allow determination of key rumen parameters and rumen particulate matter fractional outflow rates (FOR). The seven pastures studied included: native tropical grass (C 4 ) pasture (major species Heteropogon contortus and Bothriochloa bladhii), studied in the early wet (NPEW), the wet/dry transition (NPT) and the dry (NPD) seasons; introduced tropical grass (C 4 ) pasture (Bothriochloa insculpta), studied in the mid wet season (BB); the introduced tropical legumes (C 3 ), Lablab purpureus (LL) and Clitoria ternatea (BP); and the temperate grass (C 3 ) pasture, ryegrass (Lolium multiflorum, RG). Using the measured particle FOR values in calculations, the Edg estimates were very high for both C 4 and C 3 species: 0.82--0.91 and 0.95--0.98 g/g crude protein (CP), respectively. Substitution of an assumed FOR (k p = 0.02/h) for the measured values for each pasture type did not markedly affect estimates of Edg. However, C 4 tropical grasses had much lower effective rumen degradable protein (ERDP) fractions (23--66 g/kg DM) than the C 3 pasture species RG and LL (356 and 243 g/kg DM, respectively). This was associated with a lower potential degradability and degradation rate of organic matter (OM) in sacco, lower in vitro organic matter digestibility (IVOMD) and CP concentrations in the extrusa, and lower ammonia-N and branched-chain fatty acid concentrations in rumen fluid for the tropical grasses. As tropical grass pastures senesced, there was a decline in Edg, the ERDP and rumen undegradable protein (UDP) fractions, the potential degradability and degradation rate of OM and the IVOMD. These results provide useful data for estimating protein supply to cattle grazing tropical pastures.

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Spectrophotometric Determination of Ammonia as Indophenol

Cited by 403 publications

References 7 publications

Structural Insights into the Catalytic Active Site and Activity of Human Nit2/ω-Amidase

Structural Insights into the Catalytic Active Site and Activity of Human Nit2/ω-Amidase

Seasonal and multi-annual patterns ofPhragmites australisdecomposition in a wetland of the Adriatic area (Northeast Italy): a three-years analysis

Ruminal protein degradability of a range of tropical pastures

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