No abstract available.
Animals ; Electroshock* ; Glutamate Decarboxylase* ; Glutamate-Ammonia Ligase* ; Glutamic Acid* ; Glutamine* ; Hippocampus* ; Rats*

The purpose of this study was to determine the effect of regular exercise during dexamethasone injection in the body weight, weight of hind-limb muscles, myofibrillar protein content and glutamine synthetase activity. 180-200g female Wistar were divided into four groups: control, exercise, dexamethasone injection(dexa), and exercise during dexamethasone injection(D+E) group. The dexa group received daily subcutaneous injection of dexamethasone at a dose of 4mg/kg body weight for 7days. The exercise group ran on a treadmill for 60min/day(20minutes every 4 hours) at 10m/min and a 10degrees grade. The control group received daily subcutaneous injection of normal saline at a dose of 4mg/kg body weight for 7 days. The D+E group ran on a treadmill for 60min/day(20minutes every 4 hours) at 10m/min and a 10degrees grade during dexamethasone injection. Body weight of the control group increased significantly from days of experiment, that of the dexa group decreased significantly from day 4 of the dexa group decrease significantly from day 4 of the experiment resulting in a 82.4% decrease compared to the first day of the experiment. Body weight of the D+E group decrease significantly from day 5 of experiment resulting in a 81.77% decrease compared to the first day of the experiment. Body weights, muscle weight and myofibrillar protein content of the plantaris and gastrocnemius decrease significantly and muscle weight of the sleys tended to decrease with dexamethasone injection. Glutamine synthetase activity of the hind-limb muscles increase significantly with the dexamethasone injection. The relative weight of the soleus was comparable to the control group and that of plantaris decrease significantly and that of gastrocnemius tended to decrease compared to that of the control in the dexa group. Body weight and muscle weight of the plantaris and gastronemius of the exercise group were comparable to the control group, and the muscle weight of soleus showed a tendency to increase. The relative weight of the soleus increased significantly and that of the plantaris and gastrocnemius were comparable to the control in the exercise group. Myofibrillar protein content of the soleus and plantaris increased significantly and there was no change of GS activity of the hind-limb muscles compared to the control in the exercise group. Body weight of the D+E group was comparable to the dexa group, muscle weight of the hind-limb muscles increased significantly. Myofibrillar protein content of the soleus and plantaris increase significantly and that of the gastrocnemius tendency to increase compared to the dexa group. Body weight and muscle weight of the plantaris and gastrocnemius of the D+E group did not recover to that of the control group. Muscle weight of the soleus recovered to that of the control group. The relative weight and myofibrillar protein content of the hind-limb muscles recovered to that of the control group. From these results, it is suggested that regular exercise during dexamethasone injection might attenuate the muscle atrophy of the hind-limb muscles.
Animals ; Body Weight ; Dexamethasone* ; Female ; Glutamate-Ammonia Ligase ; Humans ; Injections, Subcutaneous ; Muscles ; Muscular Atrophy ; Rats*

Nitrogen is one of the most important nutrient elements for plants and a major limiting factor in plant growth and crop productivity. Glutamine synthase (GS) is a key enzyme involved in the nitrogen assimilation and recycling in plants. So far, members of the glutamine synthase gene family have been characterized in many plants such as Arabidopsis, rice, wheat, and maize. Reports show that GS are involved in the growth and development of plants, in particular its role in seed production. However, the outcome has generally been inconsistent, which are probably derived from the transcriptional and post-translational regulation of GS genes. In this review, we outlined studies on GS gene classification, QTL mapping, the relationship between GS genes and plant growth with nitrogen and the distribution characters, the biological functions of GS genes, as well as expression control at different regulation levels. In addition, we summarized the application prospects of glutamine synthetase genes in enhancing plant growth and yield by improving the nitrogen use efficiency. The prospects were presented on the improvement of nitrogen utility efficiency in crops and plant nitrogen status diagnosis on the basis of glutamine synthase gene regulation.
Arabidopsis ; Genes, Plant ; Glutamate-Ammonia Ligase ; genetics ; Nitrogen ; metabolism ; Oryza ; Plants ; enzymology ; genetics ; Triticum ; Zea mays

Glufosinate ammonium is the active ingredient in broad-spectrum contact herbicides such as BASTA(R) that inhibits the activity of glutamine synthetase, which is necessary for the production of the amino acid glutamine and for ammonia detoxification. Complications of glufosinate ammonium intoxication include gastrointestinal symptoms, loss of consciousness, convulsions, memory impairment, respiratory failure, and cardiovascular instability. We report herein a case of encephalopathy and reversible signal changes in the splenium of the corpus callosum, the bilateral corticospinal tracts, the hippocampi, and the cerebellar peduncles as seen in diffusion-weighted magnetic resonance imaging and fluid-attenuated inversion recovery images following BASTA(R) intoxication.
Ammonia ; Ammonium Compounds* ; Corpus Callosum ; Glutamate-Ammonia Ligase ; Glutamine ; Herbicides ; Magnetic Resonance Imaging ; Memory ; Pyramidal Tracts ; Respiratory Insufficiency ; Seizures ; Unconsciousness

As part of a study on the effects of dexamethasone and dehydroepiandrosterone (DHEA) on the biological roles of astrocytes in brain injury, this study evaluated the effects of dexamethasone and DHEA on the responses of primary cultured rat cortical astrocytes to lipopolysaccharide (LPS) and antimycin A. Dexamethasone decreased spontaneous release of LDH from astrocytes, and the dexamethasone effect was inhibited by DHEA. However, the inhibitory effect of DHEA on the dexamethasone-induced decrease of LDH release was not shown in astrocytes treated with LPS, and antimycin A-induced LDH release was not affected by dexamethasone or DHEA. Unlike dexamethasone, DHEA increased MTT value of astrocytes and also attenuated the antimycin A-induced decrease of MTT value. Glutamine synthetase activity of astrocytes was not affected by DHEA or LPS but increased by dexamethasone, and the dexamethasone-dependent increase was attenuated by DHEA. However, antimycin A markedly decreased glutamine synthetase activity, and the antimycin A effect was not affected by dexamethasone or DHEA. Basal release of (3H)arachidonic acid from astrocytes was moderately increased by LPS and markedly by antimycin A. Dexamethasone inhibited the basal and LPS-dependent releases of (3H)arachidonic acid, but neither dexamethasone nor DHEA affected antimycin A-induced (3H)arachidonic acid release. Basal IL-6 release from astrocytes was not affected by dexamethasone or DHEA but markedly increased by LPS and antimycin A. LPS-induced IL-6 release was attenuated by dexamethasone but was little affected by DHEA, and antimycin A-induced IL-6 release was attenuated by DHEA as well as dexamethasone. At the concentration of dexamethasone and DHEA which does not affect basal NO release from astrocytes, they moderately inhibited LPS-induced NO release but little affected antimycin A-induced decrease of NO release. Taken together, these results suggest that dexamethasone and DHEA, in somewhat different manners, modulate the astrocyte reactivity in brain injuries inhibitorily.
Animals ; Antimycin A* ; Arachidonic Acid ; Astrocytes* ; Brain Injuries ; Dehydroepiandrosterone* ; Dexamethasone* ; Glutamate-Ammonia Ligase ; Interleukin-6 ; Nitric Oxide ; Rats*

The toxic effect of ammonia on rCHO-GS cell decreased obviously due to the transfection of GS system in serum-free culture. The maximum cell density, 15.6 x 10(5) cells/mL was obtained in the culture with 1.42 mmol/L ammonia. The growth of rCHO-GS cell was inhibited with an increased ammonia concentration. However, a cell density of 8.9 x 10(5) cells/mL was obtained when the concentration of ammonia was 12.65mmol/L. The intracellar metabolic pathways were affected due to the decrease of the toxic effect of ammonia on rCHO-GS cell. With the increase of initial ammonia concentration from 0.36mmol/L to 12.65mmol/L, the yield coefficients of cell to glucose and lactate to glucose decreased. The activities of hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) increased by 43%, 140% and 25%, respectively, indicating that the utilization of glucose increased and the glycolysis pathway was more prone to efficient energy metabolism pathway. An increased activity of glutamate-pyruvate aminotransferase (GPT) showed that the conversation from glutamate to alpha-ketoglutarate was shifted to glutamate-pyruvate transamination pathway. The deamination pathway was inhibited due to a decreased activity of glutamate dehydrogenase. In addition, the number of cells in G0/G1 phase increased and the specific production rate of recombinant protein increased by 2.1-fold with the increase of initial ammonia concentration from 0.36mmol/L to 12.65mmol/L.
Ammonia ; metabolism ; toxicity ; Animals ; CHO Cells ; Cell Culture Techniques ; methods ; Cricetinae ; Cricetulus ; Culture Media, Serum-Free ; Genetic Engineering ; methods ; Glutamate-Ammonia Ligase ; genetics ; metabolism ; Glutamine ; metabolism

Glutamine is an important conditionally necessary amino acid in human body. The effort is to establish a new and high efficient L-glutamine production system instead of traditional fermentaion. In this paper, high efficiency of L-glutamine production is obtained by coupling genetic engineered bacterial glutamine synthetase (GS) with yeast alcoholic fermentation system. Glutamine Synthetase gene (glnA) was amplified from Bacillus subtilis genomic DNA with primers designed according to sequences reported in EMBL data bank, then it was inserted into expression vector PET28b, the sequence of glnA was proved to be the same as that reported in the data bank by DNA sequencing. After transformation of this recombinant plasmid PET28b-glnA into BL-21 (DE3) strain, Lactose and IPTG were used to induce GS expression at 37 degrees C separately. Both of them can induce GS expression efficiently. The induced protein is proved to be soluble and occupies about 80% of the total proteins by SDS-PAGE analysis. The soluble GS was purified by Ni2+ chelating sepharose colum. After purification, the purified enzyme was proved active. Results reveal that the optmum temperature of this enzyme is 60 degrees C and optmum pH is 6.5 in biosynthetic reaction by using glutamate, ammonium choloride and ATP as substrates. After induction, the enzyme activity in crude extract of BL-21/PET28b-glnA is 83 times higher than that of original BL-21 extract. Mn2+ can obviously increase the activity and stability of this enzyme. Experiments show that the transformation efficiency of glutamate to glutamine is more than 95%. Because of the high cost from ATP, a system coupling GS with yeast for ATP regenaration was established. In this system, GS utilizes ATP released by yeast fermentation to synthesize L-glutamine. Yeast was treated by 2% toluence to increase its permeability and a yeast named YC001 with high yield of glutamine by coupling with recombinant GS was obtained. The good efficiency was achieved with the presence of 250 mmol/L glucose and 200 mmol/L phosphate, the transformation efficiency of glutamate to glutamine in this system is more than 80%, the average yield of glutamine is about 22g/L. This provides the basis for future large scale production of L-glutamine.
Bacillus subtilis ; genetics ; metabolism ; Escherichia coli ; genetics ; metabolism ; Fermentation ; Genetic Engineering ; methods ; Glutamate-Ammonia Ligase ; biosynthesis ; genetics ; Glutamic Acid ; metabolism ; Glutamine ; biosynthesis ; genetics ; Yeasts ; genetics ; metabolism

No abstract available.
Adenoma, Liver Cell/metabolism/*pathology/surgery ; Adult ; Glutamate-Ammonia Ligase/metabolism ; Humans ; Immunohistochemistry ; Liver Neoplasms/metabolism/*pathology/surgery ; Male ; Tomography, X-Ray Computed ; beta Catenin/*metabolism

Glutamine synthetase (GS) is a key enzyme in the regulation of glutamate neurotransmission in the central nervous system. It is responsible for converting glutamate to glutamine, consuming one ATP and NH3 in the process. Glutamate is neurotoxic when it accumulates in extracellular fluids. We investigated the effects of GS in both a spinal cord injury (SCI) model and normal rats. 0.1-ml of low (2-microM) and high (55-microM) concentrations of GS were applied, intrathecally, to the spinal cord of rats under pentobarbital anesthesia. Immediately after an intrathecal injection into the L1-L3 space, the rats developed convulsive movements. These movements initially consisted of myoclonic twitches of the paravertebral muscles close to the injection site, repeated tonic and clonic contractions and extensions of the hind limbs (hind limb seizures) that spread to the fore limbs, and finally rotational axial movements of the body. An EMG of the paravertebral muscles, fore and hind limbs, showed the extent of the muscle activities. GS (2-microM) caused spinal seizures in the rats after the SCI, and GS (6-microM) produced seizures in the uninjured anesthetized rats. Denatured GS (70 degrees C, 1 hour) also produced spinal seizures, although higher concentrations were required. We suggest that GS may be directly blocking the release of GABA, or the receptors, in the spinal cord.
Animals ; Electromyography ; Female ; *Glutamate-Ammonia Ligase/administration & dosage ; Injections, Spinal ; Male ; Rats ; Rats, Long-Evans ; Seizures/*chemically induced/physiopathology ; Spinal Cord Diseases/*chemically induced/physiopathology

BACKGROUND: Hepatocellular adenoma (HCA) is a rare benign tumor of the liver. A subtype classification of HCA (hepatocyte nuclear factor 1alpha [HNF1alpha]-mutated, beta-catenin-mutated HCA, inflammatory HCA, and unclassified HCA) has recently been established based on a single institutional review of a HCA series by the Bordeaux group. METHODS: We used histologic and immunohistochemical parameters to classify and evaluate eight cases from our institution. We evaluated the new classification method and analyzed correlations between our results and those of other reports. RESULTS: Seven of our eight cases showed histologic and immunohistochemical results consistent with previous reports. However, one case showed overlapping histologic features, as previously described by the Bordeaux group. Four cases showed glutamine synthetase immunohistochemical staining inconsistent with their classification, indicating that glutamine synthetase staining may not be diagnostic for beta-catenin-mutated HCA. HNF1alpha-mutated HCA may be indicated by the absence of liver fatty acid binding protein expression. Detection of amyloid A may indicate inflammatory HCA. HCA with no mutation in the HNF1alpha or beta-catenin genes and no inflammatory protein expression is categorized as unclassified HCA. CONCLUSIONS: Although the new classification is now generally accepted, validation through follow-up studies is necessary.
Adenoma, Liver Cell* ; Amyloid ; beta Catenin ; Fatty Acid-Binding Proteins ; Glutamate-Ammonia Ligase ; Hepatocyte Nuclear Factor 1-alpha ; Liver ; Serum Amyloid A Protein