Total Amino Acid Nitrogen Research Articles

Crystalline Amino Acid Diet for Determining Amino Acid Requirements of Growing Guinea Pigs

Crystalline amino acid diets containing different levels of total nitrogen (TN) and essential amino acid (EAA) nitrogen were evaluated in 3-week growth trials to identify a diet for use in determining the amino acid requirements of growing guinea pigs. Four levels of TN (2.5, 2.9, 3.6, and 4.3%) with constant EAA/TN ratios were compared by measuring weight gain, hemoglobin and hematocrit, carcass weight and nitrogen retention of 3- to 6-week-old male Hartley guinea pigs. Three levels of EAA nitrogen (1.7, 2.0, 2.4%), with TN levels constant at 3.6%, were also compared. A diet containing 30% casein + 0.3% arginine served as a purified control diet. Water and diets were provided ad libitum. The results of this study indicate that a diet containing 3.6% TN and 1.7% EAA nitrogen supported performance comparable to that of animals fed the casein diet. Growth rates for this amino acid diet and the casein diet averaged 5.8 g/day.amino acids guinea pigs requirements

Red blood cells amino-acid pattern in protein energy malnutrition and the effect of oral dosing with single amino acids.

R.B.C.'s amino acid pattern was investigated in control and PEM subjects. The effect of oral dosing with cysteine, tryptophan and lysine on total amino acid nitrogen level of R.B.C.s was also studied. Results revealed that in moderate and severe kwashiorkor the total essential and non-essential R.B.C.'s amino acids were decreased. In 2nd grade marasmus the total R.B.C.'s amino acids in general showed lower values than normal. After oral administration of the tested amino acids, the transport index calculated as the level of maximum value of the total R.B.C.'s amino acids reached to the fasting level was lower in malnourished cases relative to controls except in 2nd grade marasmic cases given tryptophan or lysine. This criteria was considered to indicate lower rate of amino acid transport to R.B.C.s due to lower concentration in plasma or shift of transport mechanism from active transport to exchange diffusion.

Uterine uptake of amino acids throughout gestation in the unstressed ewe

The uterine uptake of 21 amino acids was determined in chronically catheterized ewes from 35 to 145 days of gestation. Total uptake of amino acids increased as gestation progressed as described by the equation: Q (mmoles/kg · day) = 0.19 gestational age (days) + 0.30. We were unable to detect a statistically significant correlation of uterine A-V concentration difference and gestational age for most amino acids. The uptakes of only eight amino acids contributed to the total increase (arginine, glutamine, valine, leucine, ornithine, isoleucine, tyrosine, phenylalanine). The amino acids which made the largest contribution to uterine uptake are similar to those which furnish the largest contributions to umbilical uptake previously reported, except for glycine, which exhibits significant umbilical uptake, but no uterine uptake. Glutamate, which is removed by the placenta from the umbilical circulation, exhibited no significant uterine uptake nor production. The total amino acid nitrogen uptake by the uterus extrapolated to 130 days’ gestation, 1.20 gm/kg fetal weight · day, closely approximates the previously reported value for umbilical amino acid nitrogen uptake at 130 days. Comparison of the individual amino acids removed from the uterine circulation with those which enter the umbilical circulation, however, suggests that metabolic conversions which involve glutamate and glycine occur in the placenta.

The flow of amino acids into the small intestine of cattle when fed heated and unheated beans (Vicia faba)

SUMMARYThe effect of substituting different amounts of heated and unheated beans for barley in diets to cows, on the flow of total nitrogen (N), total amino acid nitrogen (TAA-N) and individual amino acids into the proximal duodenum was studied. Neither heating of the beans nor increasing their proportion in the diet significantly increased the flow of total N at the duodenum; however, increasing the proportion of beans did increase the flow of TAA-N. The substitution of both forms of cracked beans for barley, and at both levels significantly increased the flows of leucine and aspartic acid; flows of histidine, isoleucine, phenylalanine and serine were increased by substitution of both forms of beans but only at the higher level. In the bean supplemented diets significant proportions of all of the ingested amino acids except methionine were apparently destroyed in the forestomachs. The substitution of beans for barley resulted in a net increase of 0·2 g TAA-N flow into the proximal small intestine for each gram of additional dietary N.

Potato composition: III. Tissue selection and its effects on total nitrogen, free amino acid nitrogen and enzyme activity (polyphenolase, monophenolase, peroxidase and catalase)

Russet Burbank, Norchip, Kennebec, White Rose, Red La Soda and Lenape tubers were sampled at harvest, after storage for 2 and 4 mo at 7 C, and after 3 wk at 20 C following each storage treatment. Freeze-dried tissue from the bud-end, stem-end and core was analyzed for total, and free amino acid nitrogen, and for monophenolase, polyphenolase, peroxidase, and catalase activities. Significant differences among cultivars and among different parts of the tuber were found for all nitrogen fractions and all enzyme activities. Storage treatments significantly changed the total and free amino acid nitrogen contents and polyphenolase, peroxidase, and catalase activities. When compared for total nitrogen content and catalase activity, differences among different parts of the tuber which were statistically significant were similar in all cultivars. However, when compared for free amino acid content, and monophenolase, polyphenolase and peroxidase activities, differences among different parts of the tuber which were statistically significant were dependent upon which cultivar was examined. The differences among cultivars which were statistically significant for all nitrogen fractions and all enzyme activities, except peroxidase, were not significantly changed by storage treatment. The differences among different parts of the tuber which were statistically significant for quantity of both nitrogen fractions and for all enzyme activities were not significantly changed by storage.

ニジマス卵抽出液中の遊離および結合型アミノ酸

Free and conjugated amino acid compositions of the trichloroacetic acid extract of maturedeggs of rainbow trout, Salmo gairdneri, were determined by column chromatography. Among the free amino acids, high levels of aspartic acid, glutamic acid, and glutamine were detected, and the sum of the nitrogen in these constituents accounted for nearly 50% of the total free amino acid nitrogen. The conjugated amino acid content in the extract of eggs was obtained from the difference between the analytical values before and after hydrolysis of the extract, and somewhat larger quantities of serine, glutamic acid, aspartic acid, and arginine were determined. The amount of serine-nitrogen accounted for nearly 30% of the total conjugated aminoacid nitrogen. In the chromatogram, the presence of a large unknown peak with a shoulder was observed in front of taurine, and the major constituent (x-component) emerging in the peak seemed to be phosphopeptide, since higher yields of serine and phosphorus were detected along with lower yields of aspartic acid, glutamic acid, arginine, etc. in the acid hydrolysate.

The effect of partially replacing urea nitrogen with protein N on N capture in the rumen of sheep fed a purified diet

1. The influence of replacing 10% of the urea nitrogen in a purified diet with casein, maize gluten or white fish meal on the efficiency of conversion of dietary-N into microbial N was examined using sheep equipped with rumen fistulas and duodenal re-entrant cannulas. 2. Total nitrogen (TN), non-ammonia nitrogen (NAN) and amino acid nitrogen (AAN) flowing to the proximal duodenum were significantly higher (P smaller than 0.05) when maize gluten was added to the diet, and this appeared to be due to an increased efficiency of microbial protein production. 3. Pepsin secretion was not significantly different between treatments and the daily amount of pepsin N flowing to the proximal duodenum was very small (40-53 mg). The peak of pepsin activity in duodenal digesta was reached 6-8 h after feeding. 4. The possible practical implications of the results are discussed.

Metabolic changes associated with iso-osmotic regulation in brain cortex slices.

Abstract— The metabolism of single, first cortical rat brain slices was studied in response to incubation in media of various osmolalities. There was an inverse relationship between osmolality and the magnitude of the increase in tissue water content, and a direct relationship between osmolality and inulin space. Brain sodium varied directly with the media sodium, but hyperosmolal sucrose and glucose resulted in a drop in brain sodium. Brain potassium was constant in hyperosmolal sodium media, but it fell in hypo‐osmolal media and hyperosmolal sucrose and glucose media.Hypo‐osmolality depressed the oxidation of [14C]glucose to 14CO2 whereas hyperosmolality obtained with sodium, sucrose, or glucose stimulated glucose oxidation. Lactate production was enhanced only by sodium hyperosmolality. Hypo‐osmolality caused a 70% drop in phosphocreatine and a minor decrease in energy charge potential, analagous to the effects of hypoxia. Hyperosmolality had no effect on energy metabolism.The total amino acid nitrogen released into the media was suppressed by hypo‐osmolality but was increased by hyperosmolal incubation. Hyperosmolality also increased production of ammonia fourfold.The time course of the change in tissue osmolality and ion content following incubation in hyperosmolal sodium media showed the tissue osmolality reached the media osmolality within 5 min, but it took 30 min for the tissue sodium to reach equilibrium with the media sodium. This indicates that unidentified or‘idiogenic osmoles’are induced transiently by hyperosmolality associated with changes in amino acid and ammonia metabolism.

Nitrogen allocation for L-Canavanine synthesis and its relationship to chemical defense of the seed

The proportion of total and free amino acid nitrogen of 7 canavanine-synthesizing leguminous seeds has been determined. These analyses reveal a disproportional allocation of total seed nitrogen into canavanine. A possible rationale for the diversion of so much total seed nitrogen into a single metabolite is offered.

Inorganic nitrogen metabolism in marine bacteria: The intracellular free amino acid pools of a marine pseudomonad

The marine pseudomonad bacterium PL1 contains an intracellular pool of free amino acids which consist mainly of glutamate with small amounts of glutamine and aspartate when grown in a nutrient medium containing 0.2 M NaCl. When the NaCl concentration of the growth medium is increased to 0.8 M, proline becomes a major component of the intracellular pool together with glutamate—at this molarity and under suitable nutrient conditions these amino acids comprise 20% of total bacterial amino acid nitrogen. When grown in a nutrient growth medium containing a constant level of NaCl, the intracellular pool size can vary by a factor of 4 depending on the concentration of carbon and nitrogen in the medium. Experiments show that the amino acid pool can act as a nitrogen reserve but has little function as a carbon reserve. At high NaCl concentrations there is a marked dependence for growth on the presence of sufficient potassium in the medium. However, no correlation between K+ and glutamate concentration in either nitrogen or K+-limited cultures has been found. None of the enzymes associated with glutamate biosynthesis was influenced by NaCl levels between 0.2 and 0.5 M. Neither Na+ or K+ stimulated the activity of these enzymes when tested in vitro.

Elimination of nitrogenous compounds by Panagrellus redivivus, Goodey, 1945 (Nematoda: Cephalobidae)

1. 1. Panagrellus redivivus incubation medium was assayed for ammonia, urea, uric acid, xanthine, hypoxanthine, total amino acid nitrogen, protein/polypeptide nitrogen and total nitrogen. 2. 2. Ammonia was the major non-protein nitrogen (NPN) compound under favourable experimental conditions, although significant amounts of urea and amino acids were also found; the NPN elimination suggested a rapid nitrogen turnover. 3. 3. Elimination of ammonia decreased, while that of amino acids increased, with increasing environmental stess on the nematodes. 4. 4. Nematode nitrogen excretion is discussed, with reference to the possible major routes of elimination.

Nitrogen components reaching the omasum and abomasum of lambs fed two nitrogen levels.

Two semipurified diets, containing either 1.12 or 2.24% soybean meal nitrogen, were fed to four wether lambs fitted with both omasal and abomasal cannulas to quantitate the nitrogen constituents reaching the omasum and abomasum. Although daily nitrogen consumption was either 7.3 or 14.6 g/lamb, intake did not affect the daily amount of total nitrogen reaching the omasum or abomasum. Significantly more free amino nitrogen reached the omasum than abomasum with both diets; the reverse situation prevailed for bound amino nitrogen. Equal or greater amounts of all amino acids, except arginine, histidine, serine and glutamic acid, reached the omasum than was consumed daily in the 1.12% nitrogen diet. Quantities of all individual amino acids consumed were greater than those recovered in the omasum or abomasum of wethers consuming the 2.24% nitrogen diet. While no significant differences were found between individual or total amino acids recovered at the two collection sites of lambs fed 1.12% nitrogen, significantly greater amounts of threonine, valine, alanine and proline reached the omasum than abomasum of lambs fed the 2.24% nitrogen diet. The absolute quantities of total nitrogen and amino acid nitrogen recovered daily in the omasum and abomasum were not influenced by the level of dietary nitrogen in this study.

Proline in Fascioliasis: I. Comparative Activities of Ornithine-d-Transaminase and Proline Oxidase in Fasciola and in Mammalian Livers

The source was sought for the high levels of proline observed in the bile of animals infected with Fasciola hepatica. Toward this end the activities of 2 key enzymes in the metabolism of proline were measured. Ornithine-4-transaminase was compared in homogenates of Fasciola, rabbit liver, and rat liver. The specific activity of the Fasciola enzyme is more than 10 times greater than that of rabbit liver and more than 7 times greater than that of rat liver. Furthermore, proline oxidase which breaks down proline in mammalian liver was absent or very low in homogenates of Fasciola. These observations strongly suggest that the worm is the source of the excessive free proline. Recent studies by Kurelec and Rijavec (1966) and Isseroff et al. (1972) have shown that free proline makes up 25 to 30% of the total free amino acid nitrogen in the trematode, Fasciola hepatica. In the latter study an increase in the total free amino acid concentration was observed in the bile of infected animals. While most free amino acids increased by approximately 40 times normal concentration, proline exhibited the greatest change in concentration with increases up to 10,000-fold. Because an increase of this magnitude in a single amino acid was likely to be of significance in the host-parasite relationship, it was of interest to determine the origin of the excessive proline. From data in the study cited above (Isseroff et al., ibid.) it was known that the concentration of proline in the worm itself was always greater than in the bile, while analysis of host tissues revealed proline in concentrations as low as those in uninfected controls. Yet it was not likely that the worms were concentrating proline from the bile. Studies by Isseroff and Read (1969) had shown that proline uptake by the worm in 2min incubations is a linear function of increasing concentration, indicating uptake by simple diffusion. Furthermore, Moss (1970) observed that proline was one of the major free amino acids excreted by Fasciola in in-vitro

Chemical methods suitable for screening for protein content and quality in cowpea (Vigna unguiculata) meals.

AbstractSeveral chemical methods have been tested for their suitability as screening procedures for estimation of the protein content and quality of cowpea (Vigna unguiculata) meals.Preliminary estimates of crude protein can be obtained by the UDY dye‐binding procedure, followed by the automated microKjeldahl (% N × 6.25) method using, for example, Carlo Erba equipment. Total amino acid nitrogen was estimated also with the Carlo Erba apparatus and for the cowpea varieties examined a positive correlation between the total amino acid nitrogen and total nitrogen contents was found. Total sulphur was evaluated as a measure of the sulpho‐amino acids in cowpea meals. Total sulphur was determined by wet digestion and subsequent turbidimetric estimation of barium sulphate. Methionine was determined in meal hydrolysates by a Locarte Autoanalyzer. Cysteine was determined either as cysteic acid on the Locarte Autoanalyzer or as bismuth sulphide.The results obtained for cowpea meals showed that there was a relatively small variation in the total sulphur and in the sulpho‐amino acid contents. Although the relation between total sulphur and sulpho‐amino acids was found to be significant at the 95% confidence level, the confidence limits were wide and at this stage a definite recommendation cannot be given as to the probable usefulness of the total sulphur‐screening procedure. A strong negative correlation was observed between both methionine and sulpho‐amino acids/16 g of N and % crude protein. Similarly, a negative relationship was observed between total sulphur/16 g of N and % crude protein.

Amino acidurie globale determinée par spectrométrie d'absorption atomique

The measurement of total urinary amino acid nitrogen can be done by a semiautomatic method based on the formation of a copper complex followed by the determination of copper by atomic absorption Spectrometry. The proposed method is sensitive, reproducible, specific and is interesting for the investigation of total hypoor hyper-excretion of urinary amino acids. However, as the percentage of the copper bound by the various amino acids is different, it will be convenient in pathologic cases to separate the various amino acids and to measure them specifically, e.g. by quantitative ion exchange resin chromatography or gas-liquid chromatography.

Nitrogen Balance of Men Fed Amino Acid Mixtures Based on Rose's Requirements, Egg White Protein, and Serum Free Amino Acid Patterns

Six healthy men were fed formula diets containing crystalline L-amino acids. Ratios of amino acids were designed according to requirements set by W. C. Rose (R); the pattern present in egg white (E); the free amino acids found in serum of fasting men maintained with 75 g egg-white proteins in the diet (S); and an inverse ratio of the serum pattern (MS). Patterns R and E were given at a level of 250 mg tryptophan in diets providing 3.5 or 7 g total amino acid nitrogen. These patterns and S and MS were also fed as diets containing 7 g total nitrogen with one-third more essential amino acids (330 mg tryptophan). Patterns E, S and MS included the nonessential amino acids, as well as the eight essential ones, according to the 250 or 330 mg tryptophan limitation. The remainder of the amino acid nitrogen in these diets and all of the nonessential amino acid nitrogen for the R pattern diets was derived from a mixture of glycine, alanine and glutamic acid. A control diet provided 12 g of pattern E essential and nonessential amino acids (1.125 g tryptophan). Fecal nitrogen content was unaffected by variation in amount of nitrogen fed (0 to 12 g/day) or the pattern of amino acids, so absorption was complete. Nitrogen balance was negative in all subjects fed the R pattern, suggesting that one or more of the eight essential acid requirements established by Rose is more than one-third below the need of our subjects and/or that an essential is missing, probably histidine. Balance was achieved with E pattern when tryptophan was 330 mg and total nitrogen 7 g/day. Patterns S and MS gave intermediate results, confirming that serum aminograms form a less adequate basis for predicting amino acid needs than does analysis of food proteins of high quality.

Plasma amino acid imbalance in patients with chronic renal failure on intermittent dialysis

The plasma amino acids in 18 patients with chronic renal failure on intermittent dialytic therapy were determined. All the patients exhibited an amino acid imbalance in which there was a significantly lower percentage of essential amino acid nitrogen (including tyrosine) in the total amino acid nitrogen. The percentage of essential amino acid nitrogen was lowest when the plasma creatinine was high. The mean levels of plasma transferrin and the ratio of the plasma tyrosine to phenylalanine were significantly reduced in these patients. A correlation was observed between the tyrosine to phenylalanine ratio and the percentage of essential amino acid nitrogen. It is concluded that both inadequate dietary intake and the degree of uraemia contribute to the amino acid imbalance.

Free amino acids in plasma, red cells and anaplasmata of parasitized calves

1. 1. Free and hydrolyzed free amino acids in plasma and erythrocytes of non-infected splenectomized calves and splenectomized calves parasitized with Anaplasma marginale were identified. 2. 2. Free and hydrolyzed free amino acids were identified in the parasites. 3. 3. Of twenty-seven ninhydrin-positive compounds found, twenty-one were identified as amino acids and quantities estimated. 4. 4. Parasitized animals had higher leucine, aspartic and α-amino- n-butyric acid and less threonine, proline, glycine, isoleucine, ornithine and arginine in plasma. 5. 5. Differences were found in amounts of individual amino acids in both plasma and erythrocytes. However, total amino acid nitrogen was nearly constant in infected vs. normal erythrocytes while a significant drop was observed in the plasma of infected vs. normal calves.

The effect of progesterone on the concentration of plasma amino acids in man

Progesterone is a catabolic hormone in man. In four subjects a progesterone induced catabolic process was accompanied by a prompt decline in the plasma concentrations of a number of free amino acids. Threonine, proline, glycine, alanine, lysine, arginine, ornithine, citrulline, cystine and serine concentrations were very significantly lowered. Valine, tyrosine, and histidine were significantly lower. The concentrations of methionine, isoleucine and leucine tended to move downward. Only the phenylalanine level was clearly uninfluenced. Previous studies had shown that total urinary amino acid nitrogen was unaffected by progesterone. Results in these experiments were corroborative in that urinary glycine, alanine, methionine and arginine were not influenced by treatment with progesterone. On the basis of these results it has been suggested that the catabolic action of progesterone is secondary to an enhancement of amino acid utilization by the liver, and that the circulating concentrations of one or several amino acids exert a negative feedback action on the rate at which amino acids are liberated from peripheral tissues. On the basis of the fact that during progesterone treatment only the concentrations of glycine, threonine, cystine and serine were lower fasting and postprandially than they were fasting on control days, it has been suggested that one of these four compounds, or a combination of several of them, may be critical in regulating peripheral protein catabolism.

Amino acid pool of the liver fluke ( Fasciola hepatica)

1. 1. The total sum of free amino acids in the liver fluke's body exceeds 300 mg/100 g of wet weight tissue. The amino acid N represents about 20 per cent of the total non-protein nitrogen (217–238 mg N/100 g wet wt. tissue). 2. 2. In the liver fluke's extract 22 amino acids have been determined. The nature of 4 ninhydrin-positive substances has not been identified. 3. 3. Alanine, proline and histidine account for 50 per cent of amino acid nitrogen. 4. 4. The findings are discussed in relation to an uneven distribution of the total amino acid's nitrogen amont the amino acids determined, and to a possible osmoregulatory function of the amino acids.