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At least 19 recordsLinked to original sources

Fine distribution of gamma-aminobutyric acid, glutamic acid decarboxylase, and glutamic acid in the rabbit cerebellum.

The fine distribution of GABA, glutamic acid decarboxylase, and glutamic acid within each layer of the rabbit cerebellar cortex was determined with microanalytical methods. The greatest glutamic acid decarboxylase activity and the highest GABA concentration were found in the Purkinje cell layer. In the distribution of GABA and glutamic acid decarboxylase the peak of glutamic acid decarboxylase activity was more pronounced than that of GABA; the concentration of glutamic acid did not show much variation between each layer.

Animals↗

A novel prodrug of salicylic acid, salicylic acid-glutamic acid conjugate utilizing hydrolysis in rabbit intestinal microorganisms.

The fate of salicylic acid-glutamic acid conjugate (salicyl-glutamic acid) following oral, intravenous, intracecal and rectal administration (60, 10, 5 and 5 mg/kg, respectively: salicylic acid equivalent) was examined in rabbits. Salicylic acid was detected in the blood 2 h after oral administration of salicyl-glutamic acid and it reached the maximum level (69.4 micrograms/ml) at 18 h after the dose. A high blood concentration of salicylic acid (24.8 micrograms/ml) was observed up to 36 h. But only a small amount of salicyl-glutamic acid was detected in the blood (less than 2.5 micrograms/ml, as salicylic acid). In contrast, unchanged salicyl-glutamic acid was found mainly in the blood following intravenous administration of salicyl-glutamic acid, suggesting that presystemic de-conjugation of salicyl-glutamic acid predominantly occurred. The intestinal mucosal de-conjugation of salicyl-glutamic acid was negligible in the in situ intestinal sac preparation with complete mesenteric venous blood collection. Immediate and very extensive salicylic acid formation in the cecum was found following intracecal administration of salicyl-glutamic acid. After oral pretreatment of rabbits with kanamycin sulfate (6 x 400 mg), a significant inhibition of salicylic acid formation following intracecal administration of salicyl-glutamic acid was observed, indicating that the intestinal microorganisms were responsible for the biotransformation of salicyl-glutamic acid. Also, in vitro incubation of salicyl-glutamic acid with gut contents showed that the primary location of hydrolysis was the hind gut.

Animals↗

Effect of transient neonatal hypothyroidism on the free aspartic acid, glutamic acid, and GABA content of different central auditory regions in the rat.

The aspartic acid, glutamic acid, and gamma-aminobutyric acid (GABA) contents were determined in four central auditory system regions in rats with transient neonatal hypothyroidism compared with control ones: the ventral and dorsal parts of the cochlear nucleus, the central nucleus of the inferior colliculus, the auditory cortex, and in an extra-auditory structure, the substantia nigra pars reticulata. The animals were sacrificed at 50 days of age, brain tissue samples were taken out by microdissection, and the free amino acids were extracted. The amino acid content was assessed by double-isotope labelling following two-dimensional thin-layer chromatography separation. GABA content was significantly decreased in both cochlear nucleus regions and glutamic acid was elevated in the inferior colliculus. Neonatal hypothyroidism had no significant effect on the aspartic acid levels in the regions studied. The results suggest an effect of neonatal hypothyroidism on regional contents of free amino acids known as candidate neurotransmitters in the auditory system.

Animals↗

A peptide containing aspartic acid, glutamic acid and serine in calf brain synaptic vesicles.

Free amino acids and other amino compounds in calf brain synaptic vesicles were identified and determined by thin-layer chromatography and ion-exchange chromatography. The vesicles contained ten identified amino acids with glutamic acid, aspartic acid, taurine and gamma-aminobutyric acid in the highest concentrations, and also cysteic acid (or cysteinesulfinic acid), glutamine, alanine, serine, glycine and lysine. The vesicles also contained certain unknown acid-labile, ninhydrin-positive compounds, one of which was a peptide yielding, after acid hydrolysis, about 40% aspartic acid, 30% serine, 15% glutamic acid, 10% glycine and possibly some alanine and lysine. The concentration of the peptide in the vesicles was as high as that of all the other amino compounds together.

Amino Acids↗

Discrimination of Rhizobium japonicum, Rhizobium lupini, Rhizobium trifolii, Rhizobium leguminosarum and of bacteroids by uptake of 2-ketoglutaric acid, glutamic acid and phosphate.

Rhizobium strains (one each of Rh. japonicum, Rh. lupini, Rh. leguminosarum) take up 2-ketoglutaric acid in general much faster and from lower concentrations in the medium than strains of Escherichia coli, Bacillus subtilis and Chromobacterium violaceum. A strain of Enterobacter aerogenes, however, is more similar to some Rhizobium strains. The same strains of Rhizobium take up also phosphate much faster and from lower concentrations than the other bacteria tested. 4 strains of Rh. lupini proved to be significantly different from 4 strains of Rh. trifolii in taking up L-glutamic acid from three to ten times lower concentration within 5 h. A similar difference was noticed between 5 strains of Rh. leguminosarum and 2 strains of Rh. japonicum for the uptake of 2-ketoglutaric acid and of L-glutamic acid. Isolated bacteroids from nodules of Glycine max var. Chippeway have a reduced uptake capacity for glutamic acid and for 2-ketoglutaric acid during the first 10-12 h, but reach the same value after 24 h as free living Rh. japonicum cells. The differences in the uptake kinetics are independent of cell concentration. The group II Rhizobium strains (Rh. japonicum and Rh. lupini, slow growing Rhizobium) are characterized by a rapid uptake of glutamic acid to a low remaining concentration of 1-3 X 10(-7) M and an uptake of 2-ketoglutaric acid to a remaining concentration of 2-5 X 10(-7) M. The group I Rhizobium strains (Rh. trifolii and Rh. leguminosarum, fast growing Rhizobium), can be characterized by a much slower uptake of both substances with a more than ten times higher concentration of both metabolites remaining in the medium after the same time.

Bacillus subtilis↗

Mitochondrial myopathy and respiratory failure associated with a new mutation in the mitochondrial transfer ribonucleic acid glutamic acid gene.

We report a novel T14687C mutation in the mitochondrial transfer ribonucleic acid glutamic acid gene in a 16-year-old boy with myopathy and lactic acidosis, retinopathy, and progressive respiratory failure leading to death. A muscle biopsy showed cytochrome c oxidase-negative ragged-red fibers, and biochemical analysis of the respiratory chain enzymes in muscle homogenate revealed complex I and complex IV deficiencies. The mutation, which affects the trinucleotide (TpsiC) loop, was nearly homoplasmic in the muscle DNA of the proband, but it was absent in his blood and in the blood from the asymptomatic mother, suggesting that it may have been a spontaneous somatic mutation in muscle.

Adolescent↗

Further studies on the fragmentation of protonated ions of peptides containing aspartic acid, glutamic acid, cysteine sulfinic acid, and cysteine sulfonic acid.

Here we examined the fragmentation, on a quadrupole ion-trap mass spectrometer, of the protonated ions of a group of peptides containing one arginine and two different acidic amino acids, one being aspartic acid (Asp) or glutamic acid (Glu) and the other being cysteine sulfinic acid [C(SO2H)] or cysteine sulfonic acid [C(SO3H)]. Our results showed that, upon collisional activation, the cleavage of the peptide bond C-terminal to C(SO2H) is much more facile than that of the peptide bond C-terminal to Asp, Glu, or C(SO3H). There is no significant difference, however, in susceptibility to cleavage of peptide bonds that are C-terminal to Asp, Glu, and C(SO3H). To understand these experimental observations, we carried out B3LYP/6-31G* density functional theory calculations for a model cleavage reaction of GXG --> b2 + Gly, in which X is Asp, Glu, C(SO2H), or C(SO3H). Our calculation results showed that the cleavage reaction is thermodynamically more favorable when X = C(SO2H) than when X = Asp or C(SO3H). We attributed the less facile cleavage of the amide bond after Glu to that the formation of a six-membered ring b ion for Glu-bearing peptides is kinetically not as favorable as the formation of a five-membered ring b ion for peptides containing the other three acidic amino acids. The results from this study may provide useful tools for peptide sequencing.

Amino Acid Sequence↗

Effects of melatonin on hypothalamic gamma-aminobutyric acid, aspartic acid, glutamic acid, beta-endorphin and serotonin levels in male mice.

Effects of melatonin on hypothalamic neurotransmitters in male mice were studied. Exogenous melatonin administered intraperitoneally significantly increased (p < 0.05) hypothalamic concentrations of aspartic acid and gamma-aminobutyric acid by over 29 and 50% respectively. Conversely, hypothalamic beta-endorphin concentration was significantly decreased (p < 0.05) 30 min after melatonin administration with doses between 5- and 100 micrograms/kg. Similarly, melatonin, at a concentration of 100 micrograms/kg, decreased (p < 0.05) the serotonin level in mouse hypothalamus by 46%. Melatonin, however, did not affect the concentration of hypothalamic glutamic acid over a dose range of 0.5-300 micrograms melatonin/kg. Our findings suggested that actions of pineal melatonin in animals such as inhibition on serum corticosterone levels might be mediated by the potentiation of activities of hypothalamic neurons containing gamma-aminobutyric acid and aspartic acid or by the inhibition of the beta-endorphin and serotonin hypothalamic neurons. The neurons containing glutamic acid in the hypothalamus were, however, not influenced by melatonin. Our results are in line with the suggestion that melatonin actions on adrenal corticosterone release or other endocrine secretions may be mediated by way of its actions on hypothalamic neurotransmitter activities.

Animals↗

[Age estimation by amino acid racemization in teeth. A comparison of data for aspartic acid, glutamic acid and alanine].

On the age estimation by the amino acid racemization analysis of dentin, besides the utilization of aspartic acid (Asp) as described in earlier reports, we further studied relationships between the D/L ratios based on glutamic acid (Glu) as well as alanine (Ala) and actual ages. The study was followed up by comparing racemization velocities of the three amino acids under some heating experiments. At four steps (6, 24, 48 and 72 hours) of hydrolysis, the coefficient values of D/L ratio of each amino acid and actual age were calculated as 0.986 to 0.994 for Asp, 0.522 to 0.806 for Glu, and 0.577 to 0.737 for Ala. The data indicate that Asp gives an extremely good result. Glu and Ala do provide reliable D/L ratios, however they are not in proportion to actual ages. Consequently, Glu and Ala seem to be much less suitable for utilization in age estimation. Reaction rate constants (k.yr-1) of racemization of Asp, Glu and Ala in antemortem teeth were 5.3825 x 10(-4), 5.1000 x 10(-5) and 2.3875 x 10(-5), respectively. Those in teeth left drying at 15 degrees C were 2.4850 x 10(-8), 1.9119 x 10(-9), and 1.11450 x 10(-9), respectively. Assuming that the reaction velocity of Asp be 1 in both living and dry states, that of Glu were calculated as 0.09 and 0.08, that of Ala, 0.04 and 0.05, indicating very similar rates. The result confirmed that both Glu and Ala gave considerably slow racemization velocities as compared with Asp.

Age Determination by Teeth↗

Comparison of age estimated from degree of racemization of aspartic acid, glutamic acid and alanine in the femur.

Aspartic acid (Asp) is generally used for estimation of age by measuring the degree of racemization. For other amino acids, however, there are few reports regarding the usefulness of the degree of racemization for the estimation of age. Accordingly, in this study using the femur (obtained from 21 cadavers) as the specimen, we measured the degree of racemization of glutamic acid (Glu) and alanine (Ala) along with Asp in the total amino acid (TAA) fraction as well as in acid-insoluble collagen-rich (IC) and acid-soluble peptide (SP) sub-fractions. We compared the degrees of racemization of each amino acid and the accuracy of the ages estimated from them. The degree of racemization and the reaction rate of racemization were ranked in the order of Asp > Glu > Ala in the TAA and IC fractions, but Asp > Ala > Glu in the SP fraction. It is noteworthy that the degrees of racemization differed between the three amino acids depending on the fraction tested. The correlation coefficient (r) between the degree of racemization and the chronological age was higher in the SP than in the TAA or IC fraction. Among three amino acids, Asp showed the highest correlation coefficient as predicted. The present study confirmed that Asp from the SP fraction is the best indicator for age estimation using racemization rates.

Adolescent↗

Gamma-aminobutyric acid, glutamic acid decarboxylase and tyrosine hydroxylase in rat striatum demonstrated by single and dual immunocytochemistry.

By means of dual ultrastructural immunostaining the followings patterns are visualized: gamma-aminobutyric acid (GABA) immunoreactive neurons, dendrites, axons and axon terminals and tyrosine hydroxylase (TH) immunopositive fibers, varicosities and boutons in rat striatum. Additionally single glutamic acid decarboxylase (GAD) immunolabeling is carried out. Four subgroups of GABA and GAD immunoreactive striatal neurons are revealed. These neuronal types are identified on the basis of sectional diameters, nuclear form and nuclear envelope invaginations, quantity of cytoplasm and cell organelles. Plasmalemmal appositions between GABAergic and between GABAergic and immunonegative neurons are observed. All subgroups of striatal GABAergic neurons contact with GABA and GAD immunoreactive, TH immunoreactive and immunonegative boutons. In the striatal neuropil numerous GABAergic, dopaminergic and immunonegative axonal endings synapsed with dendrites and spines are found out. Massive dopaminergic striatal structures using dual immunostaining is evident. Some GABA and GAD immunoreactive dendrites are revealed in direct contact with capillary walls.

Animals↗

Rapid determination of underivatized pyroglutamic acid, glutamic acid, glutamine and other relevant amino acids in fermentation media by LC-MS-MS.

Determination of amino acids in a complex matrix without derivatization is advantageous, however, difficulties are found in both the detection and the separation of those compounds. In this study, a rapid and reliable LC-MS-MS method for the quantitation of underivatized amino acids in exocellular media was established. Injections were made directly after centrifugation of the samples, without further preparation. The separation of seven underivatized amino acids was achieved on a reversed-phase C18 column with pentadecafluorooctanoic acid as a volatile ion-pair reagent, and the specific detection of most amino acids was achieved by MS-MS of the specific transitions [M + H]+-->[M + H - 46]+. The calibration curves of all analytes were linear over the range of 1.0-1000 microg ml(-1) and the detection limits ranged from 0.1 to 5 ng ml(-1), with an injection volume of 20 microl. The inter-day and intra-day precisions ranged from 2.6 to 5.7% and 4.8 to 8.2%, respectively; the mean recoveries of the seven analytes were 81-104%, 91-107% and 93-101% respectively at the spiked level of 10, 40 and 200 microg ml(-1). A large number of fermentation samples were analysed using this method. The technique is simple, rapid, selective and sensitive, and shows potential for the high-throughput quantitation of amino acids from other biological matrices.

Amino Acids↗