Developmental changes of glutamate acid decarboxylase 67 in mouse brain after hypoxia ischemia

Objective To study the developmental changes of glutamic acid decarboxylase-67 （ GAD-67, a GABA synthetic enzyme） in normal and hypoxic ischemic （HI） brain. Methods C57/BL6 mice on postnatal day （P） 5, 9, 21 and 60, corresponding developmentally to premature, term, juvenile and adult human brain were investigated by using both Western blot and immunohistochemistry methods either in normal condition or after hypoxic ischemic insult. Results The immunoreactivity of GAD67 was up regulated with brain development and significant difference was seen between mature （P21, P60） and immature （P5, P9） brain. GAD67 immunoreactivity decreased in the ipsilateral hemisphere in all the ages after hypoxia ischemia （HI） insult, but, significant decrease was only seen in the immature brain. Double labeling of GAD67 and cell death marker, TUNEL, in the cortex at 8h post-HI in the P9 mice showed that （15.6±7.0）% TUNEL positive cells were GAD67 positive which was higher than that of P60 mice. Conclusion These data suggest that GABAergic neurons in immature brain were more vulnerable to HI insult than that of mature brain.

Effects of progesterone on glutamate transporter 2 and gamma-aminobutyric acid transporter 1 expression in the developing rat brain after recurrent seizures

Seizures were induced by flurothyl inhalation. Rats were intramuscularly treated with progesterone after each seizure. Results demonstrated that glutamate transporter 2 and y-aminobutyric acid transporter 1 expression levels were significantly increased in the cerebral cortex and hippocampus of the developing rat brain following recurrent seizures. After progesterone treatment, glutamate transporter 2 protein expression was upregulated, but ^-aminobutyric acid transporter 1 levels decreased. These results suggest that glutamate transporter 2 and y-aminobutyric acid transporter 1 are involved in the pathological processes of epilepsy. Progesterone can help maintain a balance between excitatory and inhibitory systems by modulating the amino acid transporter system, and protect the developing brain after recurrent seizures.

Methods for the Determination of Stable Isotopes of Carbon and Nitrogen Directly in Valine, Proline, Glutamine, and Glutamic Acid

Amino acids are very important compounds for the body and are involved in important functions that keep us healthy. Amino acids are essential components such as valine, proline, glutamine and glutamic acid. They can be synthesized either naturally or artificially. To examine the metabolism and regulate the synthesis process, compounds labeled with nitrogen or carbon isotopes need to be used. These isotopic compounds allow for more extensive research and enable studies that would otherwise be impossible. However, their use is dependent on the availability of simple, efficient methods for isotopic analysis. Currently, the determination of the atomic fraction of carbon and nitrogen isotopes is only possible through their conversion into molecular nitrogen or carbon monoxide or carbon dioxide. This leads to the loss of information about isotopic enrichment in specific centers of the molecule. This article explores a new direct approach to determining the atomic fraction of carbon and nitrogen isotopes in the isotope-modified or identical centers of these compounds. This method eliminates the transfer process and dilution due to nitrogen and carbon impurities. It is now possible to simultaneously determine the atomic fraction of nitrogen and carbon isotopes in the research substance. This method can be applied to amino acids, making it an effective tool for proposing new research methods. Several articles [1] [2] [3] have proposed similar methods for organic compounds and amino acids.

Effects of Addition of Amino Acids or Soybean Phospholipid in Diet on Slaughter Performance and Meat Quality of Pigs

[Objectives]The study aims to discuss the effects of addition of arginine and glutamic acid or soybean phospholipid,vitamin E and yeast selenium in diet on the slaughter performance and meat quality of long(white)×large(York)binary hybrid pigs.[Methods]27 long×large castrated hybrid boars with the body weight of(54.4±0.15)kg were randomly divided into 3 groups,with 3 replicates per group and 3 pigs per replicate.Group A was the control group,in which the pigs were fed basal diet;in group B,0.8%arginine and 0.60%glutamate were added to the basal diet;in group C,75 g of soybean phospholipid,20 g of vitamin E and 8 g of yeast selenium were added to every 100 kg of the basal diet.The trial period was 60 d.After the experiment was ended,one test pig with similar body weight was selected from each replicate for slaughter and meat determination.[Results]The average weight gain and eye muscle area of the pigs in group B were significantly higher than those in group C(P<0.05),and also showed an increasing trend compared with group A,but there was no statistically significant difference(P>0.05);there was no significant difference between group B or C and group A in the average weight gain and eye muscle area(P>0.05).There was no significant difference in other slaughter performance between the three groups(P>0.05).Besides,there was also no significant difference in the content of various amino acids,total amino acids and total umami amino acids between the three groups(P>0.05).The inosine content in the longissimus dorsi muscle and muscle cooking loss of binary hybrid pigs in group C were significantly better than those in group B(P<0.05),and also had a tendency to be better than those in group A,but there was no significant difference(P>0.05);there was no significant difference between group B or C and group A in the inosine content and muscle cooking loss of the pigs(P>0.05).In addition,there was no significant difference in other meat traits and chemical composition of the longissimus dorsi muscle between group B or C and group A(P>0.05).[Conclusions]The addition of arginine and glutamic acid or soybean phospholipid,vitamin E and yeast selenium in diet had no significant effect on the growth rate,slaughter performance and meat traits of long×large binary hybrid pigs.

Adsorption of glutamic acid from aqueous solution with calcined layered double Mg-Fe-CO_3 hydroxide

Layered double Mg-Fe-CO3 hydroxide （Mg-Fe-LDH） with a mole ratio of Mg to Fe of 3 was synthesized by coprecipitation method and calcined product Mg-Fe-CLDH was obtained by heating Mg-Fe-LDH at 500 ℃ for 6 h. The as prepared Mg-Fe-LDH and calcined Mg-Fe-CLDH were used for removal of glutamic acid （Glu） from aqueous solution, respectively. Batch studies were carried out to address various experimental parameters such as contact time, pH, initial glutamic acid （Glu） concentration, co-existing anions and temperature. Glu was removed effectively （99.9%） under the optimized experimental conditions with Mg-Fe-CLDH. The adsorption kinetics follows the Ho’s pseudo second-order model. Isotherms for adsorption with Mg-Fe-CLDH at different solution temperatures were well described using the Langmuir model with a good correlation coefficient. The intraparticle diffusion model fitted the data well, which suggests that the intraparticle diffusion is not only the rate-limiting step.

RAPID DETERMINATION OF L-GLUTAMIC ACID WITH AN ENZYME REACTOR OF L-GLUTAMIC DECARBOXYLASE IMMOBILIZED ON ION EXCHANGE RESIN

The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N?methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO2 electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The properties of the immobilized enzyme on CM-CADB were studied by investigating the initial rate of the enzyme reaction, the effect of various parameters on the immobilized GDC activity and its stability. An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO2 electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamate acid. The limit of detection is 1.0×10-5 M. The linearity response is in the range of 5×10 -2-5×10 -5 M . The equation of linear regression of the calibration curve is y= 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamate acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.

Microwave-assisted Synthesis of Modified Polyaspartic Acid in Solvent

Polyaspartic acid(PASP)is suitable for the inhibition of scale deposition from water.To enhance its in- hibition efficiency,PASP was modified by reacting aspartic acid(Asp)with glutamic acid(Glu)to provide Asp-Glu copolymer under microwave irradiation.The influence of reaction parameters on conversion,molecular weight and inhibition of CaCO3 precipitation was investigated Infra-red.(IR), 1H nuclear magnetic resonance( 1H NMR)and 13C nuclear magnetic resonance( 13C NMR)spectroscopies were used to characterize the copolymer.The results show that copolymerization of aspartic acid and glutamic acid is catalyzed by a small amount of phosphorous acid (H3PO4)in solvent,the product conversion is 98.05%under the following conditions:the molar ratio of glutamic acid to reactant[Glu/(Asp+Glu)]is 0.3 and that of catalyst(Cat)to reactant[Cat/(Glu+Asp)]is 0.05(0.65ml H3PO4),the volume of solvent dimethylformamide is 16ml,the microwave power used is 720W and the reaction for 3 min.The weight average molecular weight of copolymer synthesized under these conditions is 2709 and the inhi- bition rate for CaCO3 is 97.75%.

Tanshinone IIa antagonizes spinal ischemia/reperfusion injury by interfering with upstream glutamic acid factors

Based on the hypothesis that upstream factor inhibition results in better treatment effects than downstream factor inhibition,the present study interfered with glutamic acid（Glu）-released upstream factors,such as Glu transporter function and Na＋-K＋-adenosine triphosphatases（ATPase）activity relativly.Rats with spinal cord ischemia/reperfusion injury received intraperitoneal injections of tanshinone Ila and Glu uptake and Na＋-K＋-ATPase activity were increased.Results showed that tanshinone Ila influenced Glu-released upstream factors following spinal ischemia/reperfusion injury and protected against spinal ischemia/reperfusion injury.

Antioxidant activity of bovine serum albumin binding amino acid Schiff-bases metal complexes

Glutamic acid-salicylaldehyde Schiff-base metal complexes are bound into bovine serum albumin （BSA）, which afforded BSA binding Schiff-base metal complexes （BSA-SalGluM, M=Cu, Co, Ni, Zn）. The BSA binding metal complexes were characterized by UV-vis spectra and Native PAGE. It showed that the protein structures of BSA kept after coordinating amino acid Schiff-bases metal complexes. The effect of the antioxidant activity was investigated. The results indicate that the antioxidant capacity of BSA increased more than 10 times after binding Schiff-base metal complexes.

Excitatory amino acid changes in the brains of rhesus monkeys following selective cerebral deep hypothermia and blood flow occlusion

Selective cerebral deep hypothermia and blood flow occlusion can enhance brain tolerance to ischemia and hypoxia and reduce cardiopulmonary complications in monkeys. Excitotoxicity induced by the release of a large amount of excitatory amino acids after cerebral ischemia is the major mechanism underlying ischemic brain injury and nerve cell death. In the present study, we used selective cerebral deep hypothermia and blood flow occlusion to block the bilateral common carotid arteries and/or bilateral vertebral arteries in rhesus monkey, followed by reperfusion using Ringer＇s solution at 4~C. Microdialysis and transmission electron microscope results showed that selective cerebral deep hypothermia and blood flow occlusion inhibited the release of glutamic acid into the extracellular fluid in the brain frontal lobe and relieved pathological injury in terms of the ultrastructure of brain tissues after severe cerebral ischemia. These findings indicate that cerebral deep hypothermia and blood flow occlusion can inhibit cytotoxic effects and attenuate ischemic/ hypoxic brain injury through decreasing the release of excitatory amino acids, such as glutamic acid.

Granulocyte colony-stimulating factor increases extracellular glutamic acid uptake and suppresses free radicals in an experimental model of amyotrophic lateral sclerosis

Excitatory amino acid toxicity and free radical damage play important roles in amyotrophic lateral sclerosis. Granulocyte colony-stimulating factor （G-CSF） protects nerve cells exposed to high-concentrations of glutamic acid, suggesting positive effects in the treatment of amyotrophic lateral sclerosis. The present study induced in vitro motor neuron injury using glutamic acid excitotoxicity, and the biochemical effects of G-CSF on glutamic acid concentration were determined. In addition, the effects of G-CSF on superoxide dismutase, glutathione peroxidase activity in motor neurons, and malondialdehyde and nitric oxide contents were analyzed. Immunohistochemistry was performed to measure neuronal survival. Results revealed that G-CSF significantly suppressed free radical activity, inhibited excitotoxicity, and reduced apoptosis and loss of motor neurons in the anterior horn of the spinal cord.

Analysis of Glutamic Acid in Cerebrospinal Fluid by Capillary Electrophoresis with High Frequency Conductivity Detection

A rapid method to determine glutamic acid (Glu) in cerebrospinal fluid (CSF) by capillaryelectrophoresis with high frequency conductivity detection (contactless conductivity detection) wasdescribed. The CSF sample was pretreated with silver cation resin to remove high concentration ofCl- ions in CSF. The separation was achieved in the buffer solution of 10 mmol/L Tris and 8mmol/L boric acid at the separation voltage of 20.0 kV. Glu showed linear response in the range of5.0×10-6 to 6.0×10-3 mol/L, the limit of detection was 1.0×10-6 mol/L. The method was used foranalysis Glu in CSF satisfactorily with a recovery of 97.8-98.8%.

In Vitro Biomineralization of Glutaraldehyde Crosslinked Chitosan/Glutamic Acid Films

In vitro biomineralization of glutaraldehyde crosslinked chitosan/glutamic acid films were studied. IR and ESCA （electron spectroscopy for chemical analysis） determinations confirm that chitosan and glutamic acid are successfully crosslinked by glutaraldehyde to form chitosan-glutamic acid surfaces. Composite films were soaked in saturated Ca（OH）2 solution for 8 d and then immersed in simulated body fluid （SBF） for more than 20 d. Morphological characterizations and structure of cal-cium phosphate coatings deposited on the films were studied by SEM, XRD, and EDAX （energy dispersive X-ray analysis）. Initially, the treatment in SBF results in the formation of single-layer cal-cium phosphate particles over the film surface. As immersion time increases, further nucleation and growth produce the simulated calcium-carbonate hydroxyapatite coating. ICP results show Ca/P ratio of calcium phosphate coating is a function of SBF immersion time. The inducing of glutamic acid improves the biomineralization property of chitosan films.

Tb(lll) and Ca(ll) Ion Equilibria in the Presence of Glutamic Acid and Glutamine

Tb(111) and Ca(11) ion equilibria in the presence of glutamic acid and glutamine were studied by potentiometric titration at 37'C and an ionic strength of 0. 15mol/L(NaCl) .The stability constants for Tb(111) and Ca(11)complexes in the systems were obtained. The species and their distribution in the systems were discussed.

Determination of Enantiomeric Excess of Glutamic Acids by Lab-made Capillary Array Electrophoresis

Simulated enantiomeric excess of glutamic acid was determined by a lab-made sixteen-channel capillary array electrophoresis with confocal fluorescent rotary scanner. The experimental results indicated that the capillary array electrophoresis method can accurately determine the enanfiomefic excess of glutamic acid and can be used for high-throughput screening system for combinatorial asymmetric catalysis.

Double Labeling Immulloelectron Microscopic Study on the Synaptic Connections between Glutamic Acid Neurons and GABA Neurons in the Hippocampus of Rats

Summary: In order to explore the roles of different neurotransmitters in epileptic pathogenesis, the synaptic connections between glutamic acid (Gin) neurons and GABA neurons in normal rat hippocampus were studied by pre-embedding double labeling immunoelectron microscopy. The GABA immunoreaction was first demonstrated by chromogen DAB, then the Gin immunoreaction was demonstrated by molybdic acid-TAB method. After being stabilized by DAB-cobalt chloride. the sections were processed for electron microscopic embedding. Under electron microscope, there were many Gin immunoreaction-positive neurons in the pyramidal layer of hippocampal CA1 area and some GABA immunoreaction-positive neurons with pyramidal or polygonal perikarya in the pyramidal, polymorphic and radiant layer of CA1 area. There were also symmetric dendro-axonic synapses formed by GABA-positive dendrites and Glu-positive a-cons in the polymorphic layer and symmetric axo-dendritic synapses formed by GABA-positive axons and Glu-positive dendrites in the radiant layer. In addition, there were symmetric autoregulatory axo-dendritic synapses be- tween Gin-positive axons and dendrites and autoregulatory axo-axonic synapses (both symmetric and asymmetric) between GABA-positive axons. Above mentioned results, for the first time, showed that there were complex synaptic regulatory relationships between excitatory Glu neurons and inhibitory GABA neurons in the hippocampal CA1 area, thereby, providing ultrastructural evidence for different neurotransmitters participating in epileptic pathogenesis.

Effects of Propofol on Glutamate-Induced Calcium Mobilization in Presynaptic Boutons of Rat Hippocampal Neurons

Recent reports have suggested that various general anesthetics affect presynaptic processes in the central nervous system. However, characterizations of the influence of intravenous anesthetics on neurotransmitter release from presynaptic nerve terminals (boutons) are insufficient. Because the presynaptic calcium concentration ([Ca2+]pre) regulates neurotransmitter release, we investigate the effects of the intravenous anesthetic propofol on neurotransmitter release by measuring [Ca2+]pre in the presynaptic boutons of individual dissociated hippocampal neurons. Brain slices were prepared from Sprague–Dawley rats (10 - 14 days of age). The hippocampal CA1 area was isolated with a fire-polished glass pipette, which vibrated horizontally to dissociate hippocampal CA1 neurons along with their attached presynaptic boutons. Presynaptic boutons were visualized under a confocal laser scanning microscope after staining with FM1-43 dye, and [Ca2+]pre was measured using fluo-3 AM dye. Glutamate (3 – 100 μM) administration increased [Ca2+]pre in Ca2+- containing external solution in a concentration-dependent manner. Propofol (3 – 30 μM) dose-dependently suppressed this glutamate (30 μM)-induced increase in [Ca2+]pre in boutons attached to dendrites, but not to the soma or base of the dendritic tree. The large majority of excitatory synapses on CA1 neurons are located on dendritic spines;therefore, propofol may affect glutamate-induced Ca2+ mobilization in excitatory, but not inhibitory, presynaptic boutons. Propofol may possibly have some effect on glutamate-regulated neurotransmitter release from excitatory presynaptic nerve terminals through inhibiting the increase in [Ca2+]pre induced by glutamate.

Preparation and Characterization of Orally Fast-Disintegrating Mini-Tablets Containing Diphenhydramine Hydrochloride and Aspartic or Glutamic Acid as an Umami Amino Acid

The aim of this study was to prepare diphenhydramine hydrochloride (DPH)-loaded orally fast-disintegrating mini-tablets (OFDMTs) containing either L-aspartic acid (Asp) or L-glutamic acid (Glu) as bitterness-suppressant, to characterize the prepared tablets and to evaluate their bitterness under conditions mimicking those of the oral cavity. The preparation of five formulation batches of the OFDMTs involved mixing DPH, with or without two different concentrations of Asp or Glu, and a premix containing a disintegrating agent. When all ingredients were well mixed, the mixture was directly compacted to form small (4 mm diameter) DPH-loaded OFDMTs. There were only small differences between the tablets with respect to mass, diameter, width and hardness. The disintegration times of the five formulation batches of DPH-loaded OFDMTs were measured using the OD-mate, a disintegration test apparatus in which conditions resemble those of the oral cavity. The disintegration times were all within 10 s of exposure to a medium representing the inside of the oral cavity. Rapid release profiles were observed for DPH, Asp and Glu in these dissolution tests. The taste sensor outputs of samples taken at different times (5 - 30 s) from the dissolution test solutions of the four DPH-loaded OFDMTs containing Asp or Glu were significantly inhibited compared with those of control DPH-loaded OFDMT. These results suggest that the inclusion of Asp or Glu in DPH-loaded OFDMTs is sufficient to mask bitterness in the oral cavity for the first 30 s after the tablet is placed in the mouth. It is anticipated that swallowing will have taken place within 30 s.

SYNTHESIS AND CATALYTIC PROPERTY OF POLYSTYRENE SUPPORTED GLUTAMIC ACID SCHIFF BASE COMPLEX OF Mn(Ⅱ) IN AEROBIC OXIDATION OF CYCLOHEXENE

The polystyrene supported glutamic acid Schiff base complex of Mn （ Ⅱ ） （PS-Sal-Glue-Mn） was prepared with chloromethylated styrene polymer beads, 2,4-dihydroxybenzaldehyde, L-glutamic acid and manganese （ Ⅱ ） acetate tetrahyrate. The polymeric ligand and the complex were characterized by FT-IR, small area X-ray photoelectron spectroscopy （XPS） and 1CP-AES. In the presence of the manganese complex, cyclohexene （1） was effectively oxidized by molecular oxygen without reductant. The major products of the reaction were 2-cyclohexen-l-ol （2）, 2-cyclohexen-l-one （3） and 2-cyclohexen-1- hydroperoxide （4）, which was different with typical oxidation of cyclohexene. The influence of reaction temperature and additive for oxidation had been studied. The selectivity of 2-cyclohexen-1-hydroperoxide varied with reaction time and different additives. The mechanism of cyclohexene oxidation had also been discussed.

Effects of Glutamic Acid on C-type Inactivation of Kv1.4ΔN Channel

Objectives Acidosis has an inhibitory effect on the inactivation of Kv1.4 ΔN channel through the position H508. So in order to show the effects of glutamic acid on the mutant Kv 1.4 channel that lacks N-type inactivation （Kv1.4 Δ2-146）, we studied in the expression system of the Xenopus oocytes. Methods The two-electrode voltage-clamp technique （TEV） was used to record the currents. Results Acidosis increased fKv1.4 Δ2-146 C-type inactivation. After application of glutamic acid （1 mmol/L） to Kv1.4 Δ2-146 increased C-type inactivation further, changed inactivation time constants from （2.02 ± 0.39 s ） to （1.71 ± 0.23 s） （P〈 0.05） at ＋50mv, and shifted the steady-state inactivation curves of Kv1.4 ΔN to positive potential, which was from （-44.30 ± 0.59 mV） to （-39.88 ± 0.29 mV）（P〈0.05）. and slowed the rate of recovery from inactivation, which was from （1.64 ± 0.19 s） to （1.91 ± 0.23 s）（P〈 0.05）. Conclusions Together, these results suggest that 1 mmol/L glutamic acid accelerates the C-type inactivation of Kv1.4 ΔN in pH 6.8.