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Results 401 - 450 of 634
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McNurlan M A - - 1995
This article discusses the role of amino acids in nutritional support during critical illness. The basis for assessing the requirements for protein and amino acids is presented, and the case for enhanced requirement of particular amino acids is discussed. Specific requirements for branched-chain amino acids, glutamine, and arginine are evaluated.
Bada J L - - 1995
It has been postulated that amino acid stability at hydrothermal vent temperatures is controlled by a metastable thermodynamic equilibrium rather than by kinetics. Experiments reported here demonstrate that the amino acids are irreversibly destroyed by heating at 240 degrees C and that quasi-equilibrium calculations give misleading descriptions of the experimental ...
Hoaki T - - 1995
Microbial communities in marine hydrothermal sediments (0 to 30 cm deep) in an inlet of Kodakara-Jima Island, Kagoshima, Japan, were studied with reference to environmental factors, especially the presence of amino acids. The study area was shallow, and the sea floor was covered with sand through which hot volcanic gas ...
Terry-Nathan V R - - 1995
Conditioned taste aversion presumably plays a role in the anorectic responses to amino acid-imbalanced diets that induce acute amino acid deficiency. The serotonin3 (5-HT3) receptor antagonists, tropisetron (Trop), MDL-72222 (MDL), and ondansetron, increase intake of imbalanced amino acid diets. Therefore, we tested whether 5-HT3 receptor antagonists would block an aversion ...
Leng P - - 1995
The human oncoprotein MDM2 binds with the tumor suppressor p53 and inhibits p53-directed transactivation. In this report we show that deletion of 336 amino acids from the C-terminus of human MDM2 does not decrease its efficiency to bind p53 in vivo and inhibit p53-directed transactivation. Even further deletion of MDM2 ...
Lerner N R - - 1995
Deuterium-enriched amino acids occur in the Murchison carbonaceous chrondrite. This meteorite underwent a period of aqueous alteration with isotopically light water. With the objective of setting limits on the conditions of aqueous alteration, the exchange of the carbon-bonded hydrogen atoms of amino acids with D2O has been studied from 295 ...
Völkel D - - 1995
The specific conversion of D,L-5-monosubstituted hydantoins to optically pure L-amino acids by resting cells of Arthrobacter sp. DSM 7330 has been evaluated. A new nonstereoselective hydantoinase from Arthrobacter sp. DSM 7330 was isolated and characterized. When whole cells were tested, the conversion of D,L-5-methylthioethylhydantoin (D,L-5-MTEH) led to the optically pure ...
Schutkowski M - - 1995
A series of tert-butyloxycarbonyl amino acid 4-nitroanilides, including N-alkylated amino acids and (R)-thiazolidine-4-carboxylic acid, (S)-oxazolidine-4-carboxylic acid. (4S,5S)-5-methyloxazolidine-4-carboxylic acid, (4S,5R)-5-methyloxazolidine-4-carboxylic acid, (S)-azetidine-2-carboxylic acid, (S)-pipecolic acid and (S)-3,4-dehydroproline, were prepared conveniently by the isocyanate method or the mixed anhydride procedure. The resulting amino acid 4-nitroanilides were extended to corresponding dipeptide 4-nitroanilides with ...
McDonald G D - - 1995
The Antarctic shergottite EETA79001 is believed to be an impact-ejected fragment of the planet Mars. Samples of the carbonate (white druse) and the basaltic (lithology A) components from this meteorite have been found to contain amino acids at a level of approximately 1 ppm and 0.4 ppm, respectively. The detected ...
Cooper G W - - 1995
Analyses of fractionated aqueous extracts of the Murchison meteorite by gas chromatography-mass spectrometry after silylation with N-methyl-N (tert-butyldimethylsilyl) trifluoroacetamide have revealed an extensive series of linear and cyclic aliphatic amides. These include monocarboxylic acid amides, dicarboxylic acid monoamides, hydroxy acid amides, lactams, carboxy lactams, lactims, N-acetyl amino acids, and substituted ...
Joy E K - - 1995
Production of free amino acids by some earthworm-borne microorganisms was investigated in three different synthetic media. Among the fungi tried Gliocladium roseum and Heterocephallum aurantiacum; among bacteria screened Bacillus macerans and B. mycoides; and among actinomycetes tested Streptomyces rimosus, S. violans, S. antibiticus, S. corchorusii and S. atroolivaceus produced significant ...
Ishii H - - 1995
Chitosan-amino acid conjugates were prepared by coupling amino acid esters to the carboxyl group of glyoxylic acid-substituted chitosan. The removal of heavy metals (Cu, Ni, Co and Mn) was increased by introduction of amino acids to chitosan, especially for Mn. Heavy metals were almost completely removed by chitosan-amino acid conjugates ...
Picó C - - 1995
The effect of 24 h starvation on the pool of amino acids adsorbed on the blood cell membranes was determined in Wistar rats. Aortic and iliac blood was analysed. 24 h starvation induced a significant decrease in the combined essential amino acids adsorbed on the blood cell membranes, in both ...
Teerlink T - - 1994
After a brief overview of posttranslational modifications of protein amino acids, the use of various derivatizing reagents for amino acid analysis is discussed. Derivatization and chromatographic separation of hydroxyproline, methylhistidine, and phosphorylated amino acids are discussed in detail to illustrate some of the strategies that can be applied to the ...
Young V R - - 1994
This is a brief review about the current state of knowledge concerning the minimum physiological requirements for indispensable amino acids in healthy adult humans. It is hypothesized that current international estimations of these requirements are far too low, except for the sulfur-containing amino acids. Stable isotope tracer studies of amino ...
Sala-Newby G B - - 1994
The C-terminus of the firefly luciferase (550 amino acids) was engineered using PCR followed by in vitro transcription-translation in order to investigate the role of the last 12 amino acids in the bioluminescence. Coding sequences were removed stepwise and the decapeptide MRSAMSGLHL, a putative AMP-activated protein kinase phosphorylation site, was ...
Di Giulio M - - 1994
Using the simulated annealing technique we re-examine the role played by the minimization of the physicochemical distances between amino acids during the origin of the organization of the genetic code. The results are discussed in the context of the various hypotheses proposed to explain how amino acids were allocated in ...
Valentincic T - - 1994
Intact channel catfish conditioned to the L-amino acids, proline, arginine, alanine, and lysine, discriminated these stimuli from all other amino acids tested. Behavioral structure-activity tests indicated that L-pipecolate was the only effective agonist of the L-proline conditioned response. For channel catfish in which one of the paired olfactory organs was ...
Silver M - - 1994
Blood amino acids were measured in twelve chronically catheterized mares and fetuses between 250 and 310 days gestation. The concentrations of the majority of individual amino acids were similar in maternal and fetal arterial blood and no gestational changes were detected. Only methionine, phosphoserine, 3-methyl-histidine and glutamine were consistently higher ...
Koszalka T R - - 1994
Amino acid analysis has been performed on hydrolysates of embryos/fetuses, visceral yolk sacs and ectoplacental cones/placentae from early post-implantation rat conceptuses. The increments in each amino acid between 10.5 and 11.5 days, between 11.5 and 12.5 days, and between 12.5 and 13.5 days, are expressed as percentages of the total ...
Jones W M - - 1994
A general procedure is described to determine the common free D-amino acids except D-proline in mixtures that also contain L-amino acids. The system employs exogenous pure bacterial D-amino acid transaminase coupled with 2-oxohexanoate, which accepts the amino group from D-amino acids to form D-norleucine. This amino acid is readily quantified ...
Cserháti T - - 1994
The interaction of amino acids with 14 commercial anticancer drugs was studied by charge-transfer reversed-phase thin-layer chromatography and the retention matrix was evaluated by principal component analysis. The majority of amino acids had a negligible effect on the retention of anticancer drugs. Only dicarboxy amino acids and Trp exerted a ...
Zieboll G - - 1994
We have used gel electrophoresis to study the primary covalent addition of amino acids to oligonucleotides or their analogs and the subsequent addition of further molecules of the amino acids to generate peptides covalently linked to the oligonucleotides. We have surveyed the reactions of a variety of amino acids with ...
Duran M - - 1994
The analysis of amino acids is the most frequently applied technique in the selective screening of inborn errors of metabolism. When urine is used as a starting material, simple techniques such as thin-layer chromatography or high-voltage electrophoresis is preferred as a first approach. The quantitative analysis requires instrumentation, usually an ...
Lara-Ochoa F - - 1994
An analysis of the frequency of use of amino acids on the CDR-1 and CDR-2 of 1500 immunoglobulins showed that the frequencies of amino acids in different positions could be fitted by two types of distribution. For some positions the frequencies were fitted by an inverse power law and for ...
Kalsi G - - 1993
Amino acid analysis of PRA II, a glucose-specific lectin isolated from 7 day-old peanut seedling roots shows that this lectin is rich in glycyl (103 per mole) and seryl residues (59 per mole), and poor in essential amino acids, the acidic amino acid content is higher than the basic amino ...
Farnsworth V - - 1993
A method is described for the generation of phenylthiocarbamyl (PTC) amino acids from phenylthiohydrantoin (PTH) or anilinothiazolinone (ATZ) amino acids. An aqueous base containing a reducing agent promotes the opening of the PTH or ATZ ring to form a stable PTC amino acid. The new reaction is essentially quantitative for ...
Waldroup P W - - 1993
Male Nicholas Large White turkeys were fed diets formulated to meet a minimum of 100, 110, or 120% of NRC (1984) amino acid recommendations. There were three periods when 75% of recommended standards were fed: 0 to 3 wk, 0 to 6 wk, or 6 to 12 wk. A fourth ...
Laszlo A - - 1993
Exposure of HA-1 Chinese hamster fibroblasts to amino acid analogs has been shown to have a heat-sensitizing effect as well as inducing the heat shock response (Li and Laszlo, 1985a). In this study, we have examined the effect of amino acid analogs on the development of thermotolerance after a brief ...
Niemczuk M - - 1993
Fifteen amino acids were used to investigate their effects on the pig muscle enolase. The basic and hydrophobic amino acids decreased the enzyme activity slightly. In the presence of acidic amino acids such as aspartic and glutamic acid the degree of inhibition was higher. One of the most potent inhibitors ...
Brems D N - - 1992
The importance of ProB28 and LysB29 on the self-association of insulin was established by systematically truncating the C terminus of the B chain. The relationship between structure and association was further explored by making numerous amino acid replacements at B28 and B29. Association was studied by circular dichroism, size-exclusion chromatography ...
Takemoto S - - 1992
Amino acids within the HLA class I and II molecules were first examined individually for correlation with antibody reactions of over 50,000 antisera. The amino acids that correlated with the serologic reactions were classified as serologically defined: approximately half of the amino acids fell within that category, and the other ...
Mitchell D E - - 1992
Continuous monitoring of steady-state carbon dioxide exchange rates in mature muskmelon (Cucumis melo L.) leaves showed diurnal patterns of photosynthesis and respiration that were translated into distinct patterns of accumulation and phloem export of soluble sugars and amino acids. Leaf soluble sugar patterns in general followed the pattern of photosynthetic ...
Winter H - - 1992
A comparison of barley (Hordeum vulgare L.) leaves was made between the cytosolic content of amino acids and sucrose as determined by subcellular fractionation and the corresponding concentration in phloem sap, which was collected continuously for up to 6 days from severed aphid stylets. Because amino acids were found to ...
Zenobi R - - 1992
We have analyzed the H4 ordinary chondrite Forest Vale for polycyclic aromatic hydrocarbons (PAHs) using two-step laser mass spectrometry (L2MS) and for amino acids using a standard chromatographic method. Indigenous PAHs were identified in the matrices of freshly cleaved interior faces but could not be detected in pulverized silicates and ...
Altmann F - - 1992
This report examines the RP-HPLC separation of o-phthalaldehyde derivatives of amino acids, amino sugars, and amino sugar alcohols using either 2-mercaptoethanol or 3-mercaptopropionic acid. A method with pmol sensitivity for the analysis of N-acetylamino sugars of glycoconjugates was elaborated. Upon hydrolysis, amino sugars are reduced with borohydride. Automated precolumn derivatization ...
Nagel M - - 1992
The type strains of 26 Bacillus species were investigated with respect to their capability to utilize 48 organic acids and 20 amino acids by using phenol red indicator plates and an amino acid analyzer, respectively. In addition, strains of Bacillus sphaericus were found to utilize many organic acids and amino ...
Zeier M - - 1992
We compared the glomerular filtration rate (GFR) response to amino acids in patients with glomerular disease and polycystic kidney disease. The GFR response to infusion of amino acids (75 g/12 h), of dopamine (2 micrograms/kg per min), or their combination was evaluated in nine healthy probands and in patients with ...
Zecca L - - 1991
Concentration of neurotransmitter amino acids (Tau, Gly, Asp, Glu, Gln, Ala, GABA) were measured in rat striatum following varying exposure (320 to 1408 h) to high intensity (50 Hz) electric fields. Tissue extracts in methanol, after drying, were derivatized with dansyl chloride and the amino acids quantitated by high-pressure liquid ...
Duval D - - 1991
To investigate the influence of medium amino acid resources on hybridoma cell proliferation and monoclonal antibody secretion, we first determined, in two different cell lines, the pattern of amino acid consumption. We then showed that complementation of each cell line by an amino acid solution prepared to cover its needs ...
Riens B - - 1991
Amino acid and sucrose contents were analyzed in the chloroplastic, cytosolic, and vacuolar compartments and in the phloem sap of illuminated spinach leaves (Spinacia oleracea L.). The determination of subcellular metabolite distribution was carried out by nonaqueous fractionation of frozen and lyophilized leaf material using a novel three-compartment calculation method. ...
Picó C - - 1991
It is well known that the amino acids in the blood are distributed between the plasma and inside the cells. This study was conducted to determine whether amino acids can be located adsorbed on blood cell membranes. The amino acid concentration in the deproteinized haemolysed blood was higher than that ...
Dudrick P S - - 1991
Amino acids will always be an integral part of nutritional support in all patients. The use of specific amino acids in pharmacologic doses may be beneficial to certain critically ill patients, indicating that such compounds are conditionally essential. As our knowledge of the altered regulation of amino acid metabolism in ...
Di Giulio M - - 1991
This paper analyzes the relationships between the genetic code coevolution hypothesis and the physicochemical hypothesis by means of a comparative study of the precursor-product amino acid pairs on which the former hypothesis is based. Even if the coevolution between the biosynthetic relationships of amino acids and the organization of the ...
Granum P E - - 1991
Chymotrypsin treatment of the enterotoxin from Clostridium perfringens results in the loss of 36 amino acids from the N-terminus and 3 amino acids from the C-terminus. This processing results in a 3.2 fold increase in activity on Vero cells, which is close to what had been found for trypsin treatment ...
Barrett J - - 1991
Amino acids are major constituents of biological material. Chemically they are extremely stable and combine a relatively simple molecular structure with a wide range of properties and functions. In general, amino acid metabolism in helminths has been relatively neglected and the information available is often uneven and of uncertain quality. ...
DeRuiter J - - 1990
A series of substituted N-[[(4-benzoylamino)phenyl]sulfonyl]amino acids (BAPS-amino acids) were synthesized by established methods, and the stereochemistry of the products was confirmed by HPLC analysis after chiral derivatization. When tested against aldose reductase (alditol:NADP+ oxidoreductase; EC 1.1.1.21; ALR2) isolated from rat lens, all of the BAPS-amino acids were determined to be ...
Zahnle K - - 1990
Large amounts of apparently extraterrestrial amino acids have been detected recently in rocks at the Cretaceous/Tertiary (K/T) boundary at Stevns Klint, Denmark. The amino acids were found a few tens of centimetres above and below the boundary layer, but were absent in the boundary clay itself. If one supposes that ...
May M E - - 1990
Variation in the distribution of dietary nitrogen among the different amino acids is one factor that can modify the calorie equivalent per weight of amino acid or protein. This is important to consider when experimental diets with different amino acid compositions are compared and when indirect calorimetry is used to ...
Nealon W H - - 1990
Gallbladder stasis during prolonged total parenteral nutrition (TPN) has been documented. We have examined the effect of intravenous amino acid infusion on human gallbladder contraction and release of cholecystokinin (CCK). Five healthy adult volunteers were given amino acid infusions at different rates (65, 125, 240, and 600 mg.kg-1.h-1). The volume ...
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