Amino acid contents were measured in 1- and 3-week-old primary cultures of astrocytes and in their incubation media, an amino acid-free salt solution with or without glucose, during 3-h incubation under normoxic or anoxic conditions. Most essential amino acids were rapidly released to the medium during the beginning of the ...

We studied the effects of pentylenetetrazole (PTZ) on brain amino acid metabolism in mice. Administration of this convulsant did not change forebrain concentrations of amino acids, but when treated animals also received an injection of [15N]leucine, which served as a tracer of brain nitrogen metabolism, total (14N+15N) forebrain [leucine] exceeded ...

Five balance experiments on growing pigs were carried out to study the marginal efficiency of utilization of isoleucine, leucine, valine, histidine and phenylalanine + tyrosine and to estimate their requirements for maintenance. Purified diets based on casein and crystalline amino acids as the sole source of N contained graded levels ...

The phytopathogenic fungus Sclerotium (Athelia) rolfsii CBS 191.62 is a very efficient producer of the hemoflavoprotein, cellobiose dehydrogenase (CDH), forming up to 225 mg l(-1) (15,000 units cytochrome c activity l(-1)) of this protein, which is of biotechnological interest for sensors, biocatalysis and bioremediation. Both cellulose as inducing substrate and ...

Levels of 19 proteinous amino acids and of total free amino acids were assayed by gas-liquid chromatography in cytosols of rat atrial and ventricular heart muscle cardiomyocytes. These amino acids were assayed after the rats had been exposed to either exercise (swimming) or hypoxia (hypobaric pressure of 686 hectoPascals). Out ...

In experiment 1, the effects of a group of either 20 (i.e. glutamine + essential + non-essential) or 11 (i.e. hamster embryo culture medium (HECM)-6) amino acids were evaluated in modified potassium simplex optimised medium (mKSOM) or basic medium (BM)-3. In experiment 2, the effects of glucose, pyruvate, lactate, phosphate ...

The effects of the substitution of glycine at position 42 with various other amino acid residues on the functions of CYP2D6 were studied using debrisoquine (DB) and bunitrolol (BTL) 4-hydroxylations as indices of drug-metabolizing enzymes. The substitution with hydrophobic amino acid residues such as valine and phenylalanine did not affect ...

Infections and acute mountain sickness (AMS) are common at high altitude, yet their precise etiologies remain elusive and the potential for differential diagnosis is considerable. The present study was therefore designed to compare clinical nonspecific symptoms associated with these pathologies and basic changes in free radical and amino-acid metabolism. Nineteen ...

The catabolism of phenylalanine to 2-phenylethanol and of tryptophan to tryptophol were studied by (13)C NMR spectroscopy and gas chromatography-mass spectrometry. Phenylalanine and tryptophan are first deaminated (to 3-phenylpyruvate and 3-indolepyruvate, respectively) and then decarboxylated. This decarboxylation can be effected by any of Pdc1p, Pdc5p, Pdc6p, or Ydr380wp; Ydl080cp has ...

Bed rest is associated with a loss of protein from the weight-bearing muscle. The objectives of this study are to determine whether increasing dietary branched-chain amino acids (BCAAs) during bed rest improves the anabolic response after bed rest. The study consisted of a 1-day ambulatory period, 14 days of bed ...

Exercise produces changes in protein and amino acid metabolism. These changes include degradation of the branched-chain amino acids, production of alanine and glutamine, and changes in protein turnover. One of the amino acid most affected by exercise is the branched-chain amino acid leucine. Recently, there has been an increased understanding ...

BACKGROUND: We investigated the ability of pentoxifylline, a drug with hemorheological actions known to block tumor necrosis factor-alpha (TNF-alpha) release, to modulate whole-body protein kinetics in undialyzed patients with chronic uremia. METHODS: Leucine rate of appearance (Ra) from proteolysis and leucine oxidation, a marker of net protein loss, were determined ...

The commencement of intracellular protease synthesis was studied by gelatin zymography in Bacillus thuringiensis ( Btk) HD1, Btk HD73, and a protease-deficient mutant Btk-q derived from the former strain. By gelatin zymography, a 92-kDa protease was detected first at 3 h of sporulation, which continued until 48 h, whereas two ...

Kluyveromyces marxianus has a high potential for industrial production of aroma compounds, such as 2-phenylethanol, which is derived in a bioconversion from L-phenylalanine. In the present work the product yield of K. marxianus in batch cultivation was estimated as 0.65 mol 2-phenylethanol/mol L-phenylalanine and thus significantly below the theoretical optimum ...

High levels of d-serine occur in the brain, challenging the notion that d-amino acids would not be present or play a role in mammals. d-serine levels in the brain are even higher than many l-amino acids, such as asparagine, valine, isoleucine, and tryptophan, among others. d-serine is synthesized by a ...

This study evaluated the effects of different amino acid formulations on supporting meiotic and cytoplasmic maturation of rhesus monkey (Macacca mulatta) oocytes in vitro. Five hundred and forty-six cumulus-oocyte complexes (COCs) aspirated from unstimulated adult monkey follicles (> or = 1000 microm in diameter) were cultured in either modified Connaught ...

BACKGROUND: We previously questioned the validity of the 1985 FAO/WHO/UNU upper requirement value for threonine (7 mg x kg(-1) x d(-1)) and proposed a tentative mean requirement of 15 mg x kg(-1) x d(-1). OBJECTIVE: In this study we used a 24-h indicator amino acid oxidation and balance technique, with ...

Amino acid requirements of broiler breeder chickens are not well known. The indicator amino acid oxidation (IAAO) technique was adapted for use in broiler breeders as a rapid and sensitive method to determine amino acid requirements. During IAAO, phenylalanine oxidation decreases, inversely to the changes in protein synthesis, as the ...

The requirements for branched-chain amino acids (BCAA), isoleucine, leucine and valine, in neonates have not been determined previously. Furthermore, the BCAA are considered to be catabolized primarily in the muscle and their metabolism in the small intestine has received little attention. In this study, the parenteral and enteral BCAA requirements ...

Twelve isolates of lactic acid bacteria, belonging to the Lactobacillus, Lactococcus, Leuconostoc, and Enterococcus genera, were previously isolated from 180-d-old Serra da Estrela cheese, a traditional Portuguese cheese manufactured from raw milk and coagulated with a plant rennet. These isolates were subsequently tested for their ability to catabolize free amino ...

We studied the effect of the antihyperglycemic glitazones, ciglitazone, troglitazone, and rosiglitazone, on glutamine metabolism in renal tubule-derived Madin-Darby canine kidney (MDCK) cells. Troglitazone (25 microM) enhanced glucose uptake and lactate production by 108 and 92% (both P < 0.001). Glutamine utilization was not inhibited, but alanine formation decreased and ...

The in vitro culture of Cowdria ruminantium, the causative agent of heartwater in domestic ruminants, was first achieved in 1985. Culture media were usually supplemented with serum and tryptose phosphate broth, both undefined components, contributing to great variability. Recently, we reported about the propagation of stocks of C. ruminantium in ...

Both to demonstrate whether the predominant species are dipolar ion or the neutral form and to predict the change of dipolar form to neutral form ratio in ethanol-water mixtures, the macroscopic protonation constants of eight alpha-amino acid (glycine, L-alanine, L-valine, L-leucine, L-phenylalanine, L-serine, L-methionine, and L-isoleucine) were determined potentiometrically in ...

The gene encoding the amino acid permease ArlP (Aromatic and leucine Permease) was isolated from the filamentous fungus Penicillium chrysogenum after PCR using degenerated oligonucleotides based on conserved regions of fungal amino acid permeases. The cDNA clone was used for expression of the permease in Saccharomyces cerevisiae M4054, which is ...

Stem segments prepared from pondweed (Potamo geton distinctus A. Benn.) turions (overwintering buds) elongate in anaerobic conditions, whereas there is almost no elongation in air. The anaerobic elongation was accompanied by a decrease in dry weights of stem segments, mainly due to consumption of storage starch in the amyloplasts of ...

Effect of RISUG, a newly developed male contraceptive, on various amino acids of seminal plasma ejaculates was studied by proton magnetic resonance spectroscopy at 400 MHz. Levels of amino acids were compared with the seminal plasma of obstructive azoospermia and controls. Glutamic acid, glutamine, and arginine were found to be ...

OBJECTIVE: To establish whether, in human pregnancies complicated by intrauterine growth restriction (IUGR), the maternal intravenous infusion of amino acids can increase fetal amino acid concentrations and umbilical uptake. STUDY DESIGN: Before elective cesarean delivery, a solution of amino acids was infused into a maternal vein in 8 patients with ...

INTRODUCTION: The amino acid glutamine plays an important role in the immune system by providing energy and precursors for biosynthetic processes. For lack of stability it could not so far be generally supplied in total parenteral nutrition. The development of dipeptides consisting of glutamine and a second amino acid offers ...

The transport of L-leucine, L-phenylalanine and L-alanine by the perfused lactating rat mammary gland has been examined using a rapid, paired-tracer dilution technique. The clearances of all three amino acids by the mammary gland consisted of a rising phase followed by a rapid fall-off, respectively, reflecting influx and efflux of ...

Holstein steers were used in two 5 x 5 Latin square experiments to evaluate the sparing of methionine by alternative sources of methyl groups (betaine and choline). Steers were housed in metabolism crates and limit-fed a soybean hull-based diet high in rumen degradable protein. To increase energy supply, ruminal infusions ...

Complementation of an E. coli mutant auxotrophic for the branched-chain amino acids (BCAA)--valine, leucine, and isoleucine--by the ilvG gene ( slr2088) of the cyanobacterium Synechocystis PCC6803 indicates that this gene encodes an active alpha-acetohydroxy acid synthase. Differences of response of the recombinants to the addition of the essential amino acids ...

In the last years a shift in amino acid profile was discussed as one reason for the development of staleness. Signs of staleness are among others susceptibility to infection and disturbances in well-being. Beside tryptophane and branched-chain amino acids (BCAA) glutamine is the most discussed amino acid (AA) in this ...

Chitin/dihydronicotinamide conjugates having glycine or L-leucine spacer arms have been prepared and evaluated as asymmetric reducing agents. N-Nicotinoylglycine and N-nicotinoyl-L-leucine were synthesized and coupled with the amino group of water-soluble 50%-deacetylated chitin. The remaining free amino groups were acetylated, and the nicotinamide groups were transformed into dihydronicotinamide moieties by quaternization ...

We tested the hypothesis that a reduced stimulation of whole-body protein synthesis by amino acid administration represents a major mechanism for the bed rest-induced loss of lean body mass. Healthy young subjects and matched controls were studied on the last day of a 14-day bed rest or ambulatory period, as ...

BACKGROUND & AIMS: Irreversible amino acid losses at the human ileum are not taken into account when tracer-derived amino acid requirements are calculated because the data available are scarce. We have investigated amino acid losses at the ileal level in humans after ingestion of a protein meal. METHODS: Thirteen volunteers ...

Elevated pCO(2) inhibits cell growth. This growth inhibition is accompanied by a decrease in intracellular pH (pHi), as well as a decrease in glycolysis. Elevated concentrations (mM) of some amino acids have been shown by others to protect cells exposed to two very different environmental stresses: nutrient starvation and hyperosmolality. ...

Alanine and glutamine are interorgan nitrogen/carbon carriers for ureagenesis and gluconeogenesis, which are mainly but not necessarily only hepatic. The liver is central to alanine and glutamine metabolism, but most organs can produce and use them. We studied amino acid kinetics after liver removal to depict initial events of liver ...

The neuronal effects of glucose deficiency on amino acid metabolism was studied on three-dimensional cultures of rat telencephalon neurones. Transient (6 h) exposure of differentiated cultures to low glucose (0.25 mm instead of 25 mm) caused irreversible damage, as judged by the marked decrease in the activities of two neurone-specific ...

Volatile anesthetics affect all cells and tissues tested, but their mechanisms and sites of action remain unknown. To gain insight into the cellular activities of anesthetics, we have isolated genes that, when overexpressed, render Saccharomyces cerevisiae resistant to the volatile anesthetic isoflurane. One of these genes, WAK3/TAT1, encodes a permease ...

Interrelationships between behavior and concentrations of serum amino acids in stressed rats with immobilization and water immersion were investigated. Rats were subjected to 7 h of immobilization with water-immersion stress (IWS) in each sequential day, and serum amino acids were then determined. On the first day, serum taurine, threonine, valine, ...

A series of N balance experiments using growing pigs was conducted to study the efficiency of utilization of lysine, threonine, sulphur amino acids and tryptophan and to estimate their maintenance requirements. Purified diets based on casein and crystalline amino acids as the sole source of N contained graded levels of ...

Elevation of plasma concentrations of nonesterified fatty acids (NEFA) has been reported to result in protein sparing and in impaired insulin-mediated glucose metabolism. To assess the influence of the chain length of fatty acids on these effects, medium-chain (MC) and long-chain (LC) fatty acid-containing lipid emulsions (2 mg/kg/min each) combined ...

This study evaluated the effect of branched-chain volatile fatty acids (VFA; isobutyric acid, isovaleric acid), amino acids (valine, leucine), and dipeptides (valine-valine, leucine-leucine) on neutral detergent fiber (NDF) degradation by rumen microorganisms in vitro. The CP (%) and in situ NDF degradation rate (%/h) for alfalfa, bermudagrass, and pangolagrass hays, ...

Ovomucoid is a major allergen in hen egg white which causes a serious IgE-mediated food allergy reaction. This study determined eight IgG epitopes, 5-11 amino acids in length, and nine IgE epitopes, 5-16 amino acids in length, within the primary sequence in ovomucoid using arrays of overlapping peptides synthesized on ...

This study investigates the effects of increased NH3 or amino acid supply on glutamine utilisation and production by the splanchnic tissues of fed sheep. Six sheep, prepared with vascular catheters in the aorta, mesenteric, portal and hepatic veins, were fed grass pellets to 1.1 x energy maintenance requirements. Each treatment ...

Most meteorites are thought to have originated from objects in the asteroid belt. Carbonaceous chondrites, which contain significant amounts of organic carbon including complex organic compounds, have also been suggested to be derived from comets. The current model for the synthesis of organic compounds found in carbonaceous chondrites includes the ...

The effect of infusing dipeptides or their amino acids on mohair growth of Angora goats was investigated using a skin perfusion technique. Seven Angora wethers (average BW 24 +/- 2.5 kg) were implanted bilaterally with silicon catheters into the superficial branches of the deep circumflex iliac artery and vein and ...

Values of plasma amino acids (AA) in Taiwan Chinese in different age groups were determined. AA analysis was performed by ion-exchange chromatography. The results correlated well with the reference values published by Shapira in 1989, indicating that plasma AA concentrations are not evidently affected by race and dietary habits. We ...

BACKGROUND: IVF is limited by low success rates and a confounding high multiple birth rate contributing to prematurity, increased neonatal mortality and child handicap. These problems could be overcome if single embryos of known developmental competence could be selected for transfer on day 2/3 of development, but current methods, which ...

The addition of L-alanine reduced lactate dehydrogenase leakage from primary cultured rat hepatocytes treated with galactosamine (D-gal), while D-alanine and other amino acids did not. However, the mechanisms have not yet been entirely clarified. In this study, we used various inhibitors of metabolism, i.e., aminooxyacetate, oligomycin, and quinolinic acid, to ...