Search Results
Results 251 - 300 of 1838
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Yudkoff Marc - - 2007
In many epileptic patients, anticonvulsant drugs either fail adequately to control seizures or they cause serious side effects. An important adjunct to pharmacologic therapy is the ketogenic diet, which often improves seizure control, even in patients who respond poorly to medications. The mechanisms that explain the therapeutic effect are incompletely ...
Forde Brian G - - 2007
Glutamate occupies a central position in amino acid metabolism in plants. The acidic amino acid is formed by the action of glutamate synthase, utilizing glutamine and 2-oxoglutarate. However, glutamate is also the substrate for the synthesis of glutamine from ammonia, catalysed by glutamine synthetase. The alpha-amino group of glutamate may ...
Pulido Jose E - - 2007
Diabetic retinopathy is a leading cause of vision loss. The primary clinical hallmarks are vascular changes that appear to contribute to the loss of sight. In a number of neurodegenerative disorders there is an appreciation that increased levels of excitatory amino acids are excitotoxic. The primary amino acid responsible appears ...
Hall Andrew J - - 2006
A range of 2-acrylamidopyridines, showing subtle differences in solution binding toward carboxylic acids, has been investigated as functional monomers in molecular imprinting. Imprinting of N-Z-L-glutamic acid with one such monomer is shown to be effective in the creation of a molecularly imprinted polymer (MIP) with recognition properties for its template ...
Diaz-Ruiz Araceli - - 2007
Spinal cord injury (SCI) leads to an alteration of energetic metabolism. As a consequence, glutamate, glutamine, aspartate and other important amino acids are altered after damage, leading to important disregulation of the neurochemical pathways. In the present study, we characterized the acute-phase changes in tissue concentration of amino acids involved ...
Ochiai H - - 2006
The transport system responsible for glutamine, alanine and glutamate in MOLT4 human T4 leukemia cell line were characterized. Kinetic studies of sodium-dependent glutamine and alanine transport exhibited a single saturable high-affinity carrier with a Michaelis constant of 152 +/- 26 microm and 203 +/- 36 microm and a maximal transport ...
Hutchinson Robin I - - 2006
The biosynthesis of the chlorinated amino acid [R-(Z)]-4-amino-3-chloro-2-pentenedioic acid (ACPA) was investigated. Feeding studies with Streptomyces viridogenes were conducted in resting cells. Substantial incorporation from [(15)N]- and [(13)C]-enriched glutamate and proline indicated that the biosynthetic origin of ACPA is one of these amino acids. Experiments with deuterated glutamate and proline ...
Natera V - - 2006
In the present study, the effect of acid stress on ammonium assimilation in Bradyrhizobium sp. SEMIA 6144 (Arachis hypogaea L.) microsymbiont was analyzed. The bacterial growth rate was decreased by 50%, and a significant increase in intracellular glutamate concentration was detected when the strain grew at acid pH (5.5). Assays ...
Formánek P - - 2007
The effects of demineralized water (DEMI H(2)O) and 0.5 M ammonium acetate (0.5 M AAc) on losses of L-glutamic acid and L-arginine in the course of shaking and filtration at low temperature (6 degrees C) were tested. The concentration of L-glutamic acid decreased by 6.3% in DEMI H(2)O and by ...
Bertoglio Leandro José - - 2006
The involvement of the dorsolateral periaqueductal gray in the regulation of fear-related behaviors such as escape and freezing is well established. It is still a matter of investigation, however, whether this midbrain area may have a relevant role in the modulation of more subtle defensive responses associated with anxiety such ...
Fritz Christina - - 2006
This paper investigates the influence of the carbon (C) and nitrogen (N) status on the amino acid profile in tobacco source leaves. Treatments used included growing plants at different light intensities, using an antisense RBCS (small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase) construct to inhibit Rubisco activity, growing plants on 12 or ...
Savegnago Lucielli - - 2007
The present study examined the acute toxicity and antinociceptive effects of diphenyl diselenide (PhSe)2, given orally (p.o.), in chemical and thermical models of pain in mice. Diphenyl diselenide (7.8-312 mg/kg, p.o.) did not cause mortality. This compound did not change plasma AST (aspartate aminotransferase) and ALT (alanine aminotransferase) activities as ...
Qi Zhi - - 2006
The amino acids glutamate (Glu) and glycine (Gly) trigger large, rapid rises in cytosolic Ca(2+) concentration and a concomitant rise in membrane potential (depolarization) in plants. The possibility that plant homologs of neuronal ionotropic glutamate receptors mediate these neuron-like ionic responses was tested in Arabidopsis (Arabidopsis thaliana) seedlings using a ...
Chunhachart Orawan - - 2006
The structure of the hydrolyzed product (F-2) with a molecular mass of about 2 kDa released from gamma-polyglutamic acid by the gamma-glutamyl hydrolase YwtD of Bacillus subtilis was analyzed. The results showed that F-2 is an optically heterogeneous polymer consisting of D- and L-glutamic acid in an 80:20 ratio with ...
Flythe Michael D - - 2006
Fermentation acids inhibited the growth and ammonia production of the amino-acid-fermenting bacterium Clostridium sporogenes MD1, but only when the pH was acidic. Such inhibition was traditionally explained by the ability of fermentation acids to act as uncouplers and decrease protonmotive force (Deltap), but C. sporogenes MD1 grows even if the ...
Igarashi Daisuke - - 2006
In photorespiration, peroxisomal glutamate:glyoxylate aminotransferase (GGAT) catalyzes the reaction of glutamate and glyoxylate to produce 2-oxoglutarate and glycine. Previous studies demonstrated that alanine aminotransferase-like protein functions as a photorespiratory GGAT. Photorespiratory transamination to glyoxylate, which is mediated by GGAT and serine glyoxylate aminotransferase (SGAT), is believed to play an important ...
Fisher Robin Scott - - 2007
Immunohistochemical methods were used to label singly and/or in combination glutamic acid decarboxylase (GAD, the sole synthesizing enzyme for the inhibitory neurotransmitter gamma-aminobutyric acid) and phosphate-activated glutaminase (GLN, a synthesizing enzyme for glutamate) in neurons of lateral reticular nucleus (LRN) of thalamus of adult cats. (1) GAD- and GLN-immunoreactivity (IR) ...
Bereiter D A - - 2006
Temporomandibular joint (TMJ) disorders are painful conditions that are more prevalent in women than men. This study tested the hypothesis that acute inflammation of the TMJ region evoked sex-related changes in amino acid transmitter concentrations at the trigeminal subnucleus/upper cervical cord (Vc/C2) junction, the major terminal zone for TMJ sensory ...
Cercós Manuel - - 2006
Microarrays of cDNA have been used to examine expression changes of 7000 genes during development and ripening of the fruit flesh of self-incompatible Citrus clementina, a non-climateric species. The data indicated that 2243 putative unigenes showed significant expression changes. Functional classification revealed that genes encoding for regulatory proteins were significantly ...
Wei Jianning - - 2006
Previously, we reported that l-glutamic acid decarboxylase isoform 65 (GAD65) could be cleaved in vitro to release a stable truncated form which lacks amino acid 1-69 from the N-terminus, GAD65(Delta1-69). However, whether such a truncated form is also present under certain physiological conditions remains elusive. In the present study, we ...
Cherng Jaw-Ming - - 2006
Glycyrrhizic acid is an herbal drug with a broad spectrum of antiviral activities and pharmacological effects and multiple sites of action. We investigated whether glycyrrhizic acid protects against glutamate-induced excitotoxicity and the underlying mechanisms. We found that glycyrrhizic acid protected against neurotoxicity in rat primary neuronal cultures and hippocampal slices ...
Hoshi Akihiko - - 2006
Glutamine synthetase (GS), localized to astrocyte is a key enzyme in the glutamate-glutamine pathway in the brain. 3-Nitropropionic acid (3-NPA) is an irreversible inhibitor of succinate dehydrogenase in the tricarboxylic-acid cycle, and provides ischemic tolerance to the brain. So far, there have been no reports on the relationship of astrocytic ...
Katritzky Alan R - - 2006
Diverse N-protected di-(3a-d, 3a + a', 5a-d, 5d + d', and 7a-g) and tripeptides (10a-h) were synthesized under mild reaction conditions in good yields (65-97%) by acylation with 1-(N-protected-alpha-aminoacyl)benzotriazoles of the amino groups of free aspartic and glutamic acids. Complete retention of chirality was demonstrated by parallel experiments involving D-Ala, ...
Katritzky Alan R - - 2006
Aspartic and glutamic acids were selectively extended at each of the alternative C-terminals under mild conditions to afford diverse natural and unnatural N-protected dipeptides and tripeptides in yields of 73-96%. The reactions between N-protected (alpha-aminoacyl)benzotriazoles and free amino acids or dipeptides proceeded with complete retention of chirality as supported by ...
Re Diane B - - 2006
Astrocytes have essential roles for neuron survival and function, so that their demise in neurodegenerative insults, such as ischemia, deserves attention. A major event of the cell death cascade in ischemia is the reversed operation of excitatory amino acid transporters (EAAT), releasing glutamate. Cytotoxicity is conventionally attributed to extracellular glutamate ...
Uneyama Hisayuki - - 2006
Recent advancements in molecular biology in the field of taste perception in the oral cavity have raised the possibility for ingested nutrients to be "tasted" in the upper gastrointestinal tract. The purpose of this study was to identify the existence of a nutrient-sensing system by the vagus in the rat ...
Walter Henriette - - 2006
AIMS: Though glutamic acid is well known as a working excitatory in the CNS, its impact on the modulation of alcohol withdrawal symptoms and withdrawal fits are not yet clear. The study has been undertaken to examine the levels of glutamic acid in chronic alcohol-dependent patients at different stages of ...
Harris Paul W R - - 2006
The syntheses of seven macrocyclic analogues of the neuroprotective tripeptide glycyl-L-prolyl-L-glutamic acid (GPE) are described. Macrocycles 6 and 7 mimic the cis conformer of GPE whereas macrocycles 2-5, 8, and 9 mimic the trans conformer of GPE. The macrocyclic peptides of well-defined geometry were prepared via Grubbs ring closing metathesis ...
Oshinsky Michael L - - 2006
Research techniques such as electrophysiology, cFos protein expression, and other measurements of neuronal activation provide insights into the pathophysiology of pain processing in migraine, but they do not indicate the specific neurotransmitter systems involved. This paper summarizes data from microdialysis experiments in which changes in the neurochemistry of the trigeminal ...
Csapó J - - 2007
The changes in the concentration and those of composition of alanine, aspartic acid and glutamic acid enantiomers were investigated during manufacture of Cheddar cheese. The amount of D-alanine increased continuously during ripening following the liberation of L-alanine originated from the proteolysis of milk proteins. There was slightly more D-aspartic and ...
Brown E R - - 2007
L- and D-aspartic acids (L-Asp and D-Asp) are present in the majority of nervous systems. In phylogeny, significant levels have been reported in mollusc brains, particularly cephalopods. To examine the role of L- and D-Asp on a cephalopod receptor, we studied ligand gating of a squid glutamate receptor (SqGluR) expressed ...
Venton B Jill - - 2006
Glutamate and gamma-aminobutyric acid (GABA) release in the amygdala are thought to be crucial for the acquisition and expression of fear memories, but the time course of amino acid changes during conditioning is unknown. We used rapid-sampling microdialysis with 14 s temporal resolution to address this issue. During auditory fear ...
Scaraffia Patricia Y - - 2006
We have established a protocol to study the kinetics of incorporation of 15N into glutamine (Gln), glutamic acid (Glu), alanine (Ala) and proline (Pro) in Aedes aegypti females. Mosquitoes were fed 3% sucrose solutions containing either 80 mM 15NH4Cl or 80 mM glutamine labeled with 15N in either the amide ...
Boanini Elisa - - 2006
The direct synthesis of hydroxyapatite (HA)-aspartic acid (ASP) and HA-glutamic acid (GLU) nanocrystals was carried out in presence of different amounts of the amino acids in solution. ASP and GLU incorporation into HA crystals reduces the coherent length of the perfect crystalline domains along the long dimension (002) and, even ...
Kume Toshiaki - - 2006
We have previously reported that a neuroprotective substance, serofendic acid, was purified and isolated from fetal calf serum. Here, we investigated the effect of serofendic acid on glutamate-induced apoptosis using rat primary cultures of cortical neurons. Exposure of the cortical cultures to relatively low concentration of glutamate (100 microM) induced ...
Imaizumi Akira - - 2006
Although the enhancement of amino-acid synthesis by guanosine-3',5'-tetraphosphate (ppGpp) is well known, the effect of intracellular ppGpp levels on amino-acid overproduction in Escherichia coli has not been investigated. In this study, we demonstrate that overexpression of the relA gene, encoding ppGpp synthetase, increases the accumulation of amino acids, such as ...
Chelius Dirk - - 2006
The status of the N-terminus of proteins is important for amino acid sequencing by Edman degradation, protein identification by shotgun and top-down techniques, and to uncover biological functions, which may be associated with modifications. In this study, we investigated the pyroglutamic acid formation from N-terminal glutamic acid residues in recombinant ...
Wakabayashi Yoshihiro - - 2006
PURPOSE: We analyzed the levels of glutamate and other amino acids in aqueous humor of patients with retinal artery occlusion (RAO) to determine whether glutamate is associated with retinal ischemia in RAO. METHODS: Aqueous humor samples were obtained from nine RAO patients by paracentesis performed as an emergent therapeutic intervention ...
Phanvijhitsiri Kittiporn - - 2006
Glutamine is considered a nonessential amino acid; however, it becomes conditionally essential during critical illness when consumption exceeds production. Glutamine may modulate the heat shock/stress response, an important adaptive cellular response for survival. Glutamine increases heat induction of heat shock protein (Hsp) 25 in both intestinal epithelial cells (IEC-18) and ...
Diederen Roselie M H - - 2006
Experimental models have implicated glutamate in the irreversible damage to retinal cells following retinal detachment. In this retrospective study we investigated a possible role for glutamate and other amino acid neurotransmitters during clinical rhegmatogenous retinal detachment (RRD). Undiluted vitreous samples were obtained from 176 patients undergoing pars plana vitrectomy. The ...
Sardana Ravinder K - - 2006
Glutamic acid decarboxylase (GAD) catalyzes the conversion of glutamate to gamma-aminobutyric acid (GABA) that acts as an important inhibitory neurotransmitter in the vertebrate brain, as well as in the regulation of neuroendocrine function. GAD65 and GAD67 are the two main isoforms that exist in vertebrates. The biochemical properties of recombinant ...
Koo Kyung Ah - - 2006
We have previously reported that acteoside isolated from the leaves of Callicarpa dichotoma has significant neuroprotective activity against glutamate-induced neurotoxicity in primary cultured rat cortical cells. To determine the essential structural moiety within this phenylethanoid glycoside needed to exert neuroprotective activity, acteoside was hydrolyzed with acid into its aglycones, caffeic ...
Modi Paul - - 2006
BACKGROUND: The immature heart has a much greater dependence than the adult heart on amino acid transamination in determining its ischemic tolerance. Compared with adult hearts, experimental models of the immature heart have quantified higher resting concentrations of free amino acids (AA) which are depleted by acute hypoxia. However, we ...
Spinelli Patrizia - - 2006
In the marine mollusk Aplysia limacina, a substantial amount of endogenous D-aspartic acid (D-Asp) was found following its synthesis from L-aspartate by an aspartate racemase. Concentrations of D-Asp between 3.9 and 4.6 micromol/g tissue were found in the cerebral, abdominal, buccal, pleural, and pedal ganglia. In non nervous tissues, D-Asp ...
Thalen Marcel - - 2006
The production of acellular pertussis in comparison with whole cell pertussis vaccines demands 5-25 times the amount of Bordetella pertussis' virulence factors, such as Pertussis Toxin (PT), to produce the same number of vaccine doses. An increase in the volumetric productivity by employing fed-batch rather than the currently used batch ...
Santos Sónia Sá - - 2006
Diminished activity of the alpha-ketoglutarate dehydrogenase complex (KGDHC), an important component of the tricarboxylic acid (TCA) cycle, occurs in several neurological diseases. The effect of specific KGDHC inhibitors [phosphonoethyl ester of succinyl phosphonate (PESP) and the carboxy ethyl ester of succinyl phosphonate (CESP)] on [1-13C]glucose and [U-13C]glutamate metabolism in intact ...
Zarnowski T - - 2006
The purpose of the present study was to investigate the effect of glutamate agonists upon kynurenic acid (KYNA) production in bovine retinal slices. Quantitative analysis of newly synthesized KYNA was carried out using an HPLC system and detected fluorimetrically. Glutamate at the concentration of 0.01, 0.1 and 1 mM reduced ...
Masclaux-Daubresse Céline - - 2006
Glutamate (Glu) metabolism and amino acid translocation were investigated in the young and old leaves of tobacco (Nicotiana tabacum L. cv Xanthi) using [15N]ammonium and [2-15N]Glu tracers. Regardless of leaf age, [15N]ammonium assimilation occurred via glutamine synthetase (GS; EC 6.1.1.3) and Glu synthase (ferredoxin [Fd]-GOGAT; EC 1.4.7.1; NADH-GOGAT; EC 1.4.1.14), ...
Jones T E - - 2006
The enantioselective hydrogenation of beta ketoesters over Ni-based catalysts is a rare example of a heterogeneously catalyzed chiral reaction. The key step in catalyst preparation is the adsorption from solution of chiral molecules (modifiers). One particularly interesting modifier is (S)-glutamic acid because the dominant enantiomeric product in the catalytic reaction ...
Ricoult Claudie - - 2006
Four alanine aminotransferases (AlaATs) are expressed in Medicago truncatula. In adult plants, two genes encoding mitochondrial isoforms m-AlaAT and alanine-glyoxylate aminotransferase (AGT), catalysing, respectively, reversible reactions of alanine/oxoglutarate<==>glutamate/pyruvate and alanine/glyoxylate<==>glycine/pyruvate, were expressed in roots, stems, and leaves. A gene encoding a cytosolic (c-AlaAT) isoform, catalysing the same reaction as m-AlaAT, ...
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