Non-protein Nitrogenous Substances Research Articles

Plasma urea, creatinine and uric acid concentrations in relation to feeding in peregrine falcons (Falco peregrinus)

Significant post-prandial increases in plasma uric acid and plasma urea concentrations were observed in peregrine falcons. Post-prandial uric acid concentrations were similar to those in birds suffering from hyperuricaemia and gout and were well above the theoretical limit of solubility of sodium urate in plasma. It is not clear why under normal circumstances no urate deposits occur in peregrine falcons (and probably other raptorial birds), which show hyperuricaemia for at least 12 h after ingesting a natural meal. It is important to evaluate renal function in peregrine falcons (and perhaps other birds) after a 24-h fast to avoid misinterpretation due to physiological food-induced elevated concentrations of nonprotein nitrogen substances.

QUANTIFICATION AND SOME CHEMICAL AND BIOCHEMICAL CHARACTERIZATION OF NITROGENOUS SUBSTANCES FROM VARIETIES OF COMMON BEANS (PHASEOLUS VULGARIS, L.).

Crude protein, extracted protein, and nonprotein nitrogenous substances were quantified in 55 varieties of common dry beans. Crude protein (% N x 6.25) on a dry basis varied from 23.01 to 35.22%, with a mean value of 28.51%. Methionine varied from 0.40 to 1.73% of the crude protein with a mean value of 0.80%. The ratio of globulin/albumin ranged from 1.00 to 3.31. Thirty percent of the total nitrogen was of low MW and was lost in the dialysis (MW cut off 8,000 daltons). Electrophoretic patterns (PAGE) revealed from 3 to 11 bands in the globulin fraction and 4 to 11 in the albumin fraction. Trypsin and chymotrypsin inhibitory activity was much higher in the albumin fraction than in the globulin fraction. The globulin fraction from most of the varieties was more inhibitory against trypsin than chymotrypsin. On the other hand, in the albumin fraction of the majority of the varieties the activity was stronger against chymotrypsin. Hemagglutination titer for 57 varieties ranged from 1024 to 32. Eight varieties had titers of 1024 and only four had titers of 32.

Ion-Exchange Separation of Amino Acids with Postcolumn Orthophthalaldehyde Detection

Moore's and Stein's classical ion-exchange separation of amino acids remains the standard by which all methods are judged. The adaptation of liquid chromatography (LC) equipment to amino acid analysis was inevitable because microprocessor control of gradients allowed almost infinite variation in gradient shape, producing superior resolution with only 2 buffers. The versatility of LC equipment allowed the instruments to be used for other assays. Adaptation of orthophthalaldehyde (OPA) to amino acid analysis increased detection sensitivity to the picomole range. A method for essential amino acids analysis in mechanically separated red meat and poultry products has been adapted to liquid chromatography using postcolumn hypochlorite oxidation, OPA derivatization, and fluorescence detection. Separation is achieved with 2 sequential concave exponential gradients combining ionic strength and pH increases with halide-containing buffers. Hydroxyproline and proline are detected with increasing sensitivity through the use of 3-mercaptopropionic acid in a stabilized OPA reagent. Sample preparation is a critical part of the method. A defatting procedure removes fat and other nonprotein nitrogenous substances. The hydrolysis procedure is designed to protect tryptophan which can be routinely assayed in hydrolysates with a modified flow program. Corrosion damage to the equipment by halide buffers has brought about a search for alternative methodology.

Summary-The Early Feeds: Human Milk Versus Formula and Bovine Milk

Adaptations of the gastrointestinal tract and the immune system that take place during the first year of postnatal life are of great importance, initially facilitating the transition between gestation and lactation, ultimately supporting independent postnatal life. When considering feeding options during the early periods, the roles of human milk, commercially prepared formula, and bovine milk must be evaluated in light of recent knowledge of these adaptations. Since infant feeding practices and the biologic capabilities of infants themselves vary significantly, the question arises as to what is "acceptable" v what is "optimal." NUTRITIONAL PROTEINS At present, evaluations of the amount of protein required for infant growth are based on clinical studies of largē populations and include a "margin of safety" to meet the needs of the individual infant. Based on the assumption that the milk of a given species is best adapted to the nutrient requirements of the young of that species, human infant protein requirements are determined by the protein contribution of human breast milk. Breast-milk proteins are defined broadly as either whey or casein protein with an approximate ratio of 70:30, respectively. The casein portion is divided into three subgroups: α,β and κ casein. Whey proteins are divided into six major subgroups: α-lactalbumin, β-lactoglobulin; lactoferrin; serum-albumin; lysozyme, and immunoglobulins A, G, and M. Numerous nonprotein nitrogen substances including taurine exist as well. Protein Availability Protein concentration of breast milk is approximately 1.2 g/dL when measured as total nitrogen. Nearly 25% of this is nonprotein nitrogen, much of which may not be used for nutritional purposes.

Nitrogen cycling in sheep.

Introduction Many of the difficulties in predicting the response of ruminants to supplementation of low-protein diets with non-protein nitrogen (NPN) substances arise because there is a lack of information concerning the quantities of N that recycle between the tissues and the N pools in the digestive tract. Various aspects of N mctabolism in ruminants have been examined but usually the investigations have becn restricted to intensive examination of one component rather than to more comprehensive consideration of the over-all metabolism of N and in particular of urea and ammonia N in intact and feeding animals. Whole animal studies have relied on the use of isotope-tracer techniques and recently major advances have been made using 15N-labelled compounds. In this paper, aspects of N cycling between N pools in the digestive tract and urea in blood in ruminants are discussed in an attempt to define the role of endogenous urea in digestive processes.

Acides amines libres et proteiques chez le siphonophore Forskalia edwardsi

1.1. The Siphonophore Physonect Forskalia edwardsi was studied from the point of view of protein and free amino acid composition. Its different parts were studied separately.2.2. Different parts of the colony show widely differing ratios of nitrogen/organic matter.3.3. The ratio of total amino acids/organic matter varies considerably from about 4 per cent in swimming bells to 90 per cent in fishing filaments, and non-protein nitrogenous substances have a high level.4.4. The ratio of free amino acids/total amino acids comprises between 7 and 23 per cent.5.5. Of the free amino acids, a high level of taurine is seen, up to 56 per cent in the stolon and 35 per cent in round bractea and swimming bells. Alanine reaches 21 per cent in swimming bells but no more than 4·5 per cent in other organs.6.6. Of the protein amino acids, glutamic acid has a level of 49 per cent in fishing filaments, and no more than 23 per cent in other parts of the Siphonophore.

Osmolality and Other Chemical Determinations in Postmortem Human Vitreous Humor

The measurement of osmotic pressure in blood and urine has been used extensively in clinical investigation and is beginning to be available as a diagnostic test in the hospital laboratory [1–4]. It is dependent on the number of solute particles in solution, rather than their shape, weight, or charge. The determination of the freezing point depression of a solution gives a good estimate of the number of particles and is the basis for the calculation of the osmolality. Serum osmolality has a normal range of 275 to 295 mOsm/kg, with electrolytes, particularly sodium, contributing over 90 percent of this value. Glucose, nonprotein nitrogen, and protein substances make up a large portion of the remainder. The average osmolality of urine ranges from 300 to 1090 mOsm/kg, varies with dietary intake, and is generally higher in males [3]. The mean value for cerebrospinal fluid osmolality in fifty living patients was found to be 281 mOsm/kg, and the range of values extended from 269 to 304 mOsm/kg [5]. Postmortem spinal fluid studies to date have not included osmolality determinations.

Influence of non-protein nitrogen substances on the indophenol reaction

Influence of non-protein nitrogen substances on the indophenol reaction

A study of the specificity of the Berthelot colour reaction

Evaluation of the Berthelot colour reaction has shown that reagent sequence is an important determinant of the chromogenic response. Color is formed from various non-protein nitrogen substances first treated with alkaline hypochlorite followed by phenol reagent. The time lapse before addition of phenol reagent to alkaline hypochlorite-containing mixtures is critical. The high pH promotes the volatilization of ammonia from non-protein nitrogen solutions treated with alkaline hypochlorite. This loss can be prevented by adding phenol reagent before alkaline hypochlorite. The phenol-hypochlorite reagent sequence appears to enhance the specificity of Berthelot colour formation. This reaction provides a basis for measuring urea nitrogen concentration of serum or protein-free filtrates with a degree of reliability satisfactory for most routine or research purposes.

Nutrient Distribution in Grain, Location of Nonprotein Nitrogenous Substances in Corn Grain

Nutrient Distribution in Grain, Location of Nonprotein Nitrogenous Substances in Corn Grain

Steep Liquor Constituents, Identification and Determination of Nonprotein Nitrogenous Substances in Corn Steep Liquor

Steep Liquor Constituents, Identification and Determination of Nonprotein Nitrogenous Substances in Corn Steep Liquor

The non-protein introgenous constituents of the tissues of the freshwater crayfish Astacus pallipes lereboullet

1. 1. The non-protein nitrogenous substances of the tissues of the freshwater crayfish Astacus pallipes have been examined by chromatographic methods. 2. 2. About 80 per cent of the non-protein nitrogen of abdominal muscle and 70 per cent of the non-protein nitrogen of the hepatopancreas has been accounted for. 3. 3. With the exception of betaine all the non-protein nitrogenous substances found by Kermack et al. (1955) in tissues of the marine decapped Homarus vulgaris were found in the tissues of Astacus pallipes. 4. 4. The concentrations of non-protein nitrogenous substances were much lower in the tissues of Astacus pallipes than in the tissues of Hamarus vulgaris. 5. 5. The presence of phosphorylethanolamine and of glycerylphosphorylethanolamine in the hepatopancreas of Astacus pallipes is reported.

The blood chemistry of the lower monkeys

A comparative biochemical examination of the blood of healthy people and of lower monkeys was conducted. The content of various proteins and mineral substances in the blood of lower monkeys (Macacusrhesus) was compared with that in healthy people. Certain differences in the content of proteins and in the distribution of the nonprotein nitrogen substances in the blood of human beings as compared to the blood of lower monkeys may be considered to be species specific. On the other hand the indices of the mineral metabolism in lower animals show a considerable similarity to these indices in man. Therefore, a further profound study of the nitrogen metabolism indices has future prospects from the comparative-biochemical point of view.

225. The casein number for diagnosis of mastitis. II. The effect of advanced lactation, and of storage and preservation of the milk sample

1. An investigation was made of the effect on the casein number of (a) advanced lactation, (b) storage of the milk sample at room temperature and in the refrigerator, and (c) storage of the sample at room temperature after the addition of the following preservatives: potassium dichromate, mercuric chloride, formaldehyde, crystal violet and sodium azide.2. The casein number method of mastitis diagnosis is not applicable to cows in advanced lactation. It did not distinguish between infected and uninfected quarters, as all quarters in the drying-off stage produced milk with a number below normal. At the end of lactation the mean casein, soluble protein plus non-protein, and total nitrogen contents were 21, 86, and 36% greater respectively than when the cows were in full milk.3. There was a decrease in the casein number of the milk samples on keeping at 16–18° C. or with preservatives owing to the hydrolysis of casein to proteose-peptone and non-protein nitrogenous substances. For the diagnosis of mastitis from the casein number, samples should not be kept at room temperature for more than a few hours before analysis. Keeping at 0–2° C, and at room temperature with the addition of 0·2, 0·05, and 0·01 g. potassium dichromate, formalin or mercuric chloride respectively per 100 ml. of milk, prevented significant reduction of the casein number for 24–48 hr.

175. The precipitation of the proteins in milk. I. Casein. II. Total proteins. III. Globulin. IV. Albumin and Proteose-peptone

Improved methods have been evolved for the separation of the total protein, casein, albumin, globulin, and proteose-peptone substances of milk.I. The use of acetic acid-sodium acetate solutions for the precipitation of casein is elucidated, and it is shown that the maximum precipitation of casein is rapidly effected from milk samples of varying casein content by the addition to 10 ml. of milk of about 80 ml. of water at 40° C. and 1·0 ml. of 10% acetic acid solution, followed, after 10 min., by 1·0 ml. ofNsodium acetate solution.This maximum precipitation was found to be 1·0–1·4% greater than by Moir's method, and 2·4–3·8% greater than by the method of the Association of Oflicial Agricultural Chemists.A procedure is suggested for the determination of casein which avoids the tedious transfer and washing of the precipitate, and gives enhanced ease, accuracy and speed of working.II. The advantages of trichloroacetic acid for the precipitation of proteins in determinations of the total protein and the non-protein nitrogenous substances of milk are discussed.The trichloroacetic acid methods at present in use are shown not to give complete precipitation, and for this a rapid method employing, at room temperature, a final concentration of 12% acid in the milk-acid mixture is recommended.III. An accurate method for the precipitation of globulin uncontaminated with either albumin or casein is described.IV. Methods are given for the precipitation and separation of the albumin and proteose-peptone substances.

Ionized Blood Calcium in Patients with Renal Calculi

The statement has been made that hyperparathyroidism is frequently found as the etiological factor in renal calculi.1 It becomes of interest to examine this hypothesis by all possible methods at our disposal. Since one may find normal total calcium figures in the presence of hyperparathyroidism the simple determination of the total calcium and phosphorus is not entirely reliable.McLean and Hastings2 have recently proposed a simple method for the determination of the ionized calcium in the serum. This they believe is the most sensitive test available for detecting the presence of hyperparathyroidism.Twenty-four patients with proven calcium stones were referred to the Metabolic Clinic by the Second Surgical Service (Dr. Edwin Beer). The Collip modification of the Tisdall method was used for the determination of the total serum calcium, and the Fiske-Subbarow method for the inorganic phosphorus. The serum proteins, after removal of non-protein nitrogenous substances, were determined by a modification of the ...

餌料蛋白の化學的研究

With the object of applying the van Slyke method to the study of the nutritive value of the protein in feeding-stuffs, we investigated first the extent of the error arising from the presence of interfering substances, and then searched for the simplest method to enable us to obviate, or at least to reduce, the chief source of error. Casein was hydrolyzed with or without the addition of the following substances: starch, sucrose, filter paper, olive oil, and agar-agar. The addition of fat influences the analytical results slightly, while the addition of carbohydrate interferes to a much greater extent with the determination of amino acids, by the method under consideration. These results coincide with those of YANAGAWA and NISHIMURA. Hence, before subjecting the sample to the van Slyke method, it is quite necessary to treat feeding-stuffs so that all the proteins separated from the interfering substances. By treating the sample in such a manner as to boil with water and precipitate with acetic acid, it was easily possible to free the proteins from most of non-protein nitrogenous substances and hotwater-soluble carbohydrates, of which the main parts of the carbohydrates in feeding-stuffs consist. Our experiment showed that the recovery of nitrogen in the form of coagulable nitrogen amounted in the cases of sardine muscle and soy-bean to 94-95% of the protein nitrogen after the Stutzer method, and to 91% of the protein nitrogen in the case of silk-worm pupa. Even following the above method, the fibre, which is contained only in the feeding-stuffs of plant origin, will remain in the coagulable protein part. Thereafter, we made further experiment, in which casein mixed with equal amount of fibre was analyzed on one hand by the original van Slyke method, and on the other hand by the Hamilton method, and by the another modified method in which analysis was made in the filtrate obtained after removal of the residue insoluble in 20% HCl. From the results obtained by these three methods, it was evident that there is no choice, on the whole, between them. Hence, we conclude that it is not necessary to treat the sample of feeding-stuffs with such a complex manner as HAMILTON recommends, if we analyze the isolated coagulable protein above-mentioned, which is free from most of the interfering substances.

餌料蛋白の化學的研究

With the object of applying the van Slyke method to the study of the nutritive value of the protein in feeding-stuffs, we investigated first the extent of the error arising from the presence of interfering substances, and then searched for the simplest method to enable us to obviate, or at least to reduce, the chief source of error. Casein was hydrolyzed with or without the addition of the following substances: starch, sucrose, filter paper, olive oil, and agar-agar. The addition of fat influences the analytical results slightly, while the addition of carbohydrate interferes to a much greater extent with the determination of amino acids, by the method under consideration. These results coincide with those of YANAGAWA and NISHIMURA. Hence, before subjecting the sample to the van Slyke method, it is quite necessary to treat feeding-stuffs so that all the proteins separated from the interfering substances. By treating the sample in such a manner as to boil with water and precipitate with acetic acid, it was easily possible to free the proteins from most of non-protein nitrogenous substances and hotwater-soluble carbohydrates, of which the main parts of the carbohydrates in feeding-stuffs consist. Our experiment showed that the recovery of nitrogen in the form of coagulable nitrogen amounted in the cases of sardine muscle and soy-bean to 94-95% of the protein nitrogen after the Stutzer method, and to 91% of the protein nitrogen in the case of silk-worm pupa. Even following the above method, the fibre, which is contained only in the feeding-stuffs of plant origin, will remain in the coagulable protein part. Thereafter, we made further experiment, in which casein mixed with equal amount of fibre was analyzed on one hand by the original van Slyke method, and on the other hand by the Hamilton method, and by the another modified method in which analysis was made in the filtrate obtained after removal of the residue insoluble in 20% HCl. From the results obtained by these three methods, it was evident that there is no choice, on the whole, between them. Hence, we conclude that it is not necessary to treat the sample of feeding-stuffs with such a complex manner as HAMILTON recommends, if we analyze the isolated coagulable protein above-mentioned, which is free from most of the interfering substances.