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Results 401 - 450 of 1837
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Orsi Nicolas M - - 2004
The accumulation of ammonium is a major artefact of in vitro embryo culture. This study has examined ammonium production and potential mechanisms of disposal in preimplantation bovine blastocysts. Embryos were produced by in vitro maturation and fertilisation of oocytes, and cultured in synthetic oviduct fluid containing amino acids and BSA ...
Wada Takehiko - - 2004
A novel nucleic acid model using peptide ribonucleic acid (PRNA), which contains 5-amino-5-deoxyribonucleoside as a recognition site for nucleic acids and consists D-glutamic acid (D-PRNA) instead of L-glutamic acid (L-PRNA) as a backbone structure, has been designed and synthesized. Difference between D-PRNA and L-PRNA oligomers was elucidated on the basis ...
Holladay Johnathan E - - 2004
Technology to convert biomass into chemical building blocks provides an opportunity to displace fossil fuels and increase the economic viability of biorefineries. Coupling fermentation capability with aqueous-phase catalysis provides novel routes to monomers and chemicals, including those not accessible from petrochemical routes. Glutamic acid provides a platform to numerous compounds ...
Oliveira Leida Calegário - - 2003
Several pools of neurotoxic peptides obtained from fractionated Phoneutria nigriventer venom induce different toxicological effects. One of them, PhTx4, is highly toxic towards insects and displays only a slight toxicity when injected in mice. Also, this fraction contains a class of peptides that are able to inhibit glutamate uptake in ...
MacCallum Justin L - - 2003
We calculated the free energy of solvation of the neutral analogs of 18 amino acid side-chains (not including glycine and proline) using the OPLS all-atom force field in TIP4P water, SPC water, and cyclohexane by molecular dynamics simulation and thermodynamic integration. The average unsigned errors in the free energies of ...
Salcedo Ernesto E Department of Cell and Developmental Biology, University of Colorado Health Sciences Center, Denver, Colorado 80262, - - 2003
Invertebrates are sensitive to a broad spectrum of light that ranges from UV to red. Color sensitivity in the UV plays an important role in foraging, navigation, and mate selection in both flying and terrestrial invertebrate animals. Here, we show that a single amino acid polymorphism is responsible for invertebrate ...
Ambroggio Xavier I - - 2004
The JAMM (JAB1/MPN/Mov34 metalloenzyme) motif in Rpn11 and Csn5 underlies isopeptidase activities intrinsic to the proteasome and signalosome, respectively. We show here that the archaebacterial protein AfJAMM possesses the key features of a zinc metalloprotease, yet with a distinct fold. The histidine and aspartic acid of the conserved EX(n)HS/THX(7)SXXD motif ...
Kusaka Takashi - - 2004
The aim of this study was to determine the validity of the hypothesis that excitatory amino acids are related to phosphorylation potential during primary and secondary cerebral energy failure observed in asphyxiated infants. We report here the results of experiments using newborn piglets subjected to severe transient cerebral hypoxia-ischemia followed ...
Hall Andrew J - - 2003
The preparation of a molecularly imprinted polymer against N-Z-L-glutamic acid using a novel bis-urea functional monomer is described. The polymer exhibits affinity for the template over N-Z-protected aspartic acid and glycine and, further, is capable of binding larger molecules, e.g., the anti-cancer drug methotrexate, containing the glutamate substructure.
Cavero S - - 2003
The malate-aspartate NADH shuttle in mammalian cells requires the activity of the mitochondrial aspartate-glutamate carrier (AGC). Recently, we identified in man two AGC isoforms, aralar1 and citrin, which are regulated by calcium on the external face of the inner mitochondrial membrane. We have now identified Agc1p as the yeast counterpart ...
Gruss M - - 2003
In vivo microdialysis and behavioural studies in the domestic chick have shown that glutamatergic as well as monoaminergic neurotransmission in the medio-rostral neostriatum/hyperstriatum ventrale (MNH) is altered after auditory filial imprinting. In the present study, using pharmaco-behavioural and in vivo microdialysis approaches, the role of dopaminergic neurotransmission in this juvenile ...
Prabhu Ramamoorthy - - 2003
BACKGROUND: Our earlier work has shown that surgical manipulation of the intestine results in oxidative stress and mucosal damage along with alterations in the brush border membrane (BBM). Glutamine feeding is known to offer protection against damage to mucosa under various conditions and this study looked at the effect of ...
Retyunskaya M V - - 2003
We studied the effects of a new dipeptide neuroleptic Dilept (N-caproyl-L-prolyl-L-tyrosine methyl ester) on activity of neurotransmitter systems in the brain. Dilept possessed antidopamine, glutamate modulatory, and cholinomimetic properties. These data indicate that Dilept is of potential efficacy in relieving positive and negative symptoms of schizophrenia.
Xie Qiang - - 2003
Aspartate is an osmolyte found in some marine invertebrates and cyclostome fish. The aspartate-induced unfolding of N-acylamino acid amido hydrolase (aminoacylase) has been studied by measuring enzyme activity, fluorescence emission spectra, 8-anilino-1-naphthalenesulfonate (ANS) fluorescence spectra and far-UV circular dichroism (CD) spectra. The results showed that aspartate caused the inactivation and ...
LeDay A M - - 2003
In a previous study, we showed evidence that oxidative stress induced by hydrogen peroxide (H2O2) can inhibit the release of [3H]-D-aspartate from the bovine isolated retina, in vitro. The aim of the present study was to investigate the effect of H2O2 on glutamate and glycine levels in the bovine retina ...
Milton Sarah L - - 2003
While frogs such as Rana temporaria are known to withstand 4-5 h anoxia at room temperature, little is known about the neurological adaptations that permit this. Previous research has shown that changes in neuroactive compounds such as glutamate and dopamine in anoxia-sensitive (mammalian) brains follow a strikingly different pattern than ...
Schmidt Jochen - - 2003
We have studied the feasibility of fast high-performance liquid chromatography coupled to electrospray ionization mass spectrometry in the selected ion monitoring mode for the quantitative determination of aspartic acid in an aspartate drug. Internal standardization was required, but mass spectrometric detection allowed for very short retention times of approximately 0.5 ...
Hernández José V - - 2003
Combination of a binaphthyl unit with chromenone benzoxazole fragments provided a chiral receptor that is enantioselective for glutamic acid and its derivatives. The receptor racemic mixture was resolved by TLCs impregnated with (R,R)-thiodilactic acid. High association constants were measured for dansylglutamic acid, using a fluorescent method. This receptor can be ...
Daydé Sandrine - - 2003
As a nonessential element, aluminum is likely to be toxic both at low usual dietary levels in the long run (chronic toxicity) and at high therapeutic levels in shorter periods of time (acute toxicity). In both situations, aluminum toxicity is a direct function of aluminum bioavailability, which is itself dependent ...
Liao Su-Lan - - 2003
Microenvironmental changes including elevated levels of L-glutamate, ionic homeostasis, acidification, and oxygen level are associated with brain insults. Their effects on energy metabolism were studied in cultured astrocytes. L-glutamate caused a decrease in lactate accumulation through the activation of transporter in astrocytes in a concentration- and time-dependent manner. Decreases in ...
Hermann Thomas - - 2003
In the 1950s Corynebacterium glutamicum was found to be a very efficient producer of L-glutamic acid. Since this time biotechnological processes with bacteria of the species Corynebacterium developed to be among the most important in terms of tonnage and economical value. L-Glutamic acid and L-lysine are bulk products nowadays. L-Valine, ...
Ma Zhuo - - 2003
Commensal and pathogenic strains of Escherichia coli possess three inducible acid resistance systems that collaboratively protect cells against acid stress to pH 2 or below. The most effective system requires glutamate in the acid challenge media and relies on two glutamate decarboxylases (GadA and B) combined with a putative glutamate:gamma-aminobutyric ...
Phillis J W - - 2003
Brain extracellular levels of glutamate, aspartate, GABA and glycine increase rapidly following the onset of ischemia, remain at an elevated level during the ischemia, and then decline over 20-30 min following reperfusion. The elevated levels of the excitotoxic amino acids, glutamate and aspartate, are thought to contribute to ischemia-evoked neuronal ...
Erikson Keith M - - 2003
Brain extracellular concentrations of amino acids (e.g. aspartate, glutamate, taurine) and divalent metals (e.g. zinc, copper, manganese) are primarily regulated by astrocytes. Adequate glutamate homeostasis is essential for the normal functioning of the central nervous system (CNS). Glutamate is of central importance for nitrogen metabolism and, along with aspartate, is ...
Sanabria Emilio R Garrido ER Department of Anatomy and Neurobiology, Program in Neuroscience, University of Maryland School of Medicine, Baltimore 21201, - - 2004
We tested the hypothesis that endogenous N-acetylaspartylglutamate (NAAG) presynaptically inhibits glutamate release at mossy fiber-CA3 synapses. For this purpose, we made use of 2-(3-mercaptopropyl)pentanedioic acid (2-MPPA), an inhibitor of glutamate carboxypeptidase II [GCP II; also known as N-acetylated alpha-linked acidic dipeptidase (NAALADase)], the enzyme that hydrolyzes NAAG into N-acetylaspartate and ...
Bui B V - - 2003
We wanted to determine the characteristics associated with electrophysiological and neurochemical changes secondary to ischemic insult as well as correlate these electrophysiological and neurochemical changes. A Ganzfeld source was used to elicit electroretinograms in anesthetized adult Sprague-Dawley rats. Following baseline recordings, one eye was removed for control quantitative amino acid ...
Waterman Scott R - - 2003
Strains of Escherichia coli K-12, O157:H7, and Shigella flexneri grown to stationary phase in complex unbuffered media can survive for several hours at pH 2.5. This stationary-phase acid resistance phenotype is dependent upon the alternate sigma factor sigmas and the supplementation of either glutamate or glutamine in the acidified media ...
Duarte Ana Isabel - - 2003
In this study, we investigated the in vitro effect of exogenously administered insulin on the susceptibility to oxidative stress and on the accumulation of the amino acid neurotransmitters gamma-aminobutyric acid (GABA) and glutamate in a synaptosomal fraction isolated from male Wistar rat brain cortex. Insulin (1 microM) did not affect ...
Conti Paola - - 2003
Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them behaved as antagonists at mGluR1,5 and as agonists at ...
Antonini G - - 2003
The cause of downbeat nystagmus (DBN) remains undiagnosed in about 40% of patients. This paper reports the presence of antiglutamic acid decarboxylase antibodies (GAD-Ab) in a patient with DBN. Antibodies against GABAergic neurons located in the vestibular complex may induce chemical denervation of the floccular neurons, which normally suppress the ...
Richards Douglas A - - 2003
The amino acid content of hourly microdialysis samples from nine severely head-injured children was examined. Of particular interest was the measurement of the excitatory amino acid glutamate, as high levels of this substance, which are associated with the excitotoxicity cascade, have been linked to high intracranial pressure and poor outcome ...
Galvan Adriana - - 2003
A technique for continuous on-line detection of glutamate using brain microdialysis in awake primates is described. The method is based on an enzymatic assay using fluorescence detection of glutamate. The time resolution of the continuous fluorescent readout compares favorably with that of most published studies, which have used standard high-pressure ...
Davies J A - - 2003
Bilobalide is one of many active constituents found in EGb 761 (definition see editorial), which is extracted from Ginkgo biloba leaves. Whilst there is good, sound evidence that bilobalide exhibits neuroprotective actions in a variety of model systems, there is currently no consensus on its mechanism of action. This present ...
Noguchi Yasushi - - 2003
Corynebacterium ammoniagenes is an overproducer of xanthosine-5'-monophosphate (XMP) by consuming either glcose (glc) or glutamic acid (glu). Its energy metabolism was studied in vivo using 31P NMR spectroscopy coupled with a circulating fermentation system (CFS). CFS enabled us to validate directly the cellular dependency on carbon sources and changes in ...
Oh Suk-Heung - - 2003
Changes in the concentrations of gamma-aminobutyric acid (GABA), soluble calcium ions, glutamic acid, and the activity of glutamate decarboxylase (GAD) were investigated in non-germinated vs. germinated brown rice. Brown rice was germinated for 72 h by applying each of the following solutions: (1) distilled water, (2) 5 mM lactic acid, ...
Qureshi Adnan I - - 2003
OBJECTIVE: To determine whether extracellular concentrations of glutamate and other amino acids are significantly elevated after intracerebral hemorrhage and, if so, the temporal characteristics of these changes. Although the role of excitotoxic amino acids, particularly that of glutamate, has been described in ischemic stroke and head trauma, no information exists ...
Brennan Lorraine - - 2003
A series of glutamate analogues, known as gliotoxins, are toxic to astrocytes in culture, and are inhibitors or substrates of high affinity sodium-dependent glutamate transporters. The mechanisms by which these gliotoxins cause toxicity are not fully understood. The effects of a series of gliotoxic amino acids (L-alpha-aminoadipate, L-serine-O-sulphate, D-aspartate and ...
Dakshinamurti Krishnamurti - - 2003
Electroencephalographic recordings in cerebral cortex of mice given a single sub-convulsive dose of domoic acid exhibited typical spike and wave discharges. Administration of the anti-epileptic drugs sodium valproate, nimodipine, or 5 alpha-pregnan 3 alpha-ol-20-one as well as pyridoxine simultaneously with or after domoic acid treatment resulted in significantly less spike ...
Bodrova M E - - 2003
At low Ca2+ concentrations the pore of the inner mitochondrial membrane can open in substates with lower permeability (Hunter, D. R., and Haworth, R. A. (1979) Arch. Biochem. Biophys., 195, 468-477). Recently, we showed that Ca2+ loading of mitochondria augments the cyclosporin A-dependent decrease in transmembrane potential (DeltaPsi) across the ...
Yu Siming - - 2003
The effects of aniracetam on extracellular amino acid levels in the hippocampus of conscious gerbils, with or without transient cerebral ischemia/reperfusion, were measured by microdialysis and reverse phase-high performance liquid chromatography. Increased extracellular levels of aspartate and glutamate that were observed in the hippocampus of conscious gerbils during transient global ...
Novak Donald - - 2003
Marginal giant cells within the rodent placenta are important sources of androgens, critical to maintenance of pregnancy. Androgen synthesis requires NADPH, a by-product of glutamate oxidation. We examined the uptake of glutamate into rat choriocarcinoma cells, which have been shown to maintain many of the characteristics of marginal giant cells ...
Thibodeaux Stefan J - - 2003
This study examines the role of steric hindrance near the stereogenic centers of four glutamic acid based polymeric surfactants. The single amino acid surfactants of glutamic acid, glutamic acid methyl ester, glutamic ethyl ester, and glutamic acid tert-butyl ester were investigated. The micellar electrokinetic chromatography (MEKC) separation of three binaphthyl ...
Yu K W - - 2003
The chemical components of freeze-dried stromata from Cordyceps scarabaecola were examined. The stromata consisted of crude carbohydrates (55.1%) and crude proteins (14.2%). The stromata were also composed of a low content of crude ash (6.6%) and fat (1.5%). The composition of the carbohydrate in the stromata included a large quantity ...
Feng Yi - - 2003
Gabapentin has recently been used clinically as an antihyperalgesic agent to treat certain neuropathic pain states. The aim of this study is to test whether gabapentin is able to inhibit responses to peritoneal irritation-induced visceral pain and to examine the effect of gabapentin on spinal cord amino acid release. The ...
Honkanen Robert A - - 2003
OBJECTIVE: To measure vitreous concentrations of glutamate and other amino acids in patients with glaucoma undergoing vitrectomy. METHODS: Undiluted vitreous samples were collected from patients undergoing vitrectomy at the University of Iowa (Iowa City) between 1997 and 1998 (n = 69). Vitreous concentrations of 16 amino acids, including glutamate, were ...
Newsholme P - - 2003
Glucose is widely accepted as the primary nutrient for the maintenance and promotion of cell function. This metabolite leads to production of ATP, NADPH and precursors for the synthesis of macromolecules such as nucleic acids and phospholipids. We propose that, in addition to glucose, the 5-carbon amino acids glutamine and ...
Baran H - - 2003
It has been shown recently that the L-kynurenine metabolite kynurenic acid lowers the efficacy of mitochondria ATP synthesis by significantly increasing state IV, and reducing respiratory control index and ADP/oxygen ratio of glutamate/malate-consuming heart mitochondria. In the present study we investigated the effect of L-tryptophan (1.25 microM to 5 mM) ...
Rebillard G - - 2003
In the cochlea, glutamate plays a major role in synaptic transmission between the inner hair cell and the primary auditory neurons. Extracellular glutamate concentration must be regulated to prevent excitotoxicity. This regulation is mediated by excitatory amino acid transporters, membrane proteins that remove glutamate from the synaptic cleft. In this ...
Richard Hope T - - 2003
To colonize and cause disease, enteric pathogens must overcome environmental challenges that include acid stress in the host's stomach as well as short-chain fatty acid stress in the intestine of the host and reservoir. Three known inducible systems have evolved for stationary phase acid resistance in E. coli. These systems ...
Nakajima Kumiko - - 2003
A new glass capillary microelectrode for L-glutamate is described using pulled glass capillaries (tip size, approximately 12.5 microm) with a very small volume (approximately 2 microl) of inner solution containing glutamate oxidase (GluOx) and ascorbate oxidase. The operation of the electrode is based on capillary action that samples L-glutamate into ...
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