The Experts below are selected from a list of 79452 Experts worldwide ranked by ideXlab platform
Xiaoyuan Wang - One of the best experts on this subject based on the ideXlab platform.
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Metabolic engineering of Escherichia coli to produce Gamma-Aminobutyric Acid using xylose.
Applied microbiology and biotechnology, 2017Co-Authors: Anqi Zhao, Xiaoyuan WangAbstract:Biomass-derived xylose is an economically interesting substrate for the sustainable microbial production of value-added compounds. Escherichia coli could barely use xylose to directly produce Gamma-Aminobutyric Acid. In this study, E. coli strains that could directly produce Gamma-Aminobutyric Acid were developed through the deletion of eight genes sucA, puuE, gabT, gabP, xylA, xylB, waaC, and waaF, and the overexpression of two E. coli genes gadB and gdhA, as well as five Caulobacter crescent genes CcxylA, CcxylB, CcxylC, CcxylD, and CcxylX. Both E. coli strains W3110 and JM109 could directly produce Gamma-Aminobutyric Acid from xylose after either overexpression of the seven genes or deletion of the eight genes. Overexpression of the seven genes of in the multiple deletion mutants further increased Gamma-Aminobutyric Acid production. Among the 28 recombinant E. coli strains constructed in this study, the highest Gamma-Aminobutyric Acid was produced by JWZ08/pWZt7-g3/pWZt7-xyl. JWZ08/pWZt7-g3/pWZt7-xyl could produce 3.95 g/L Gamma-Aminobutyric Acid in flask cultivation, using xylose as the sole carbon source.
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Extracellular expression of glutamate decarboxylase B in Escherichia coli to improve Gamma-Aminobutyric Acid production.
AMB Express, 2016Co-Authors: Anqi Zhao, Cheng Chen, Xiaoyuan WangAbstract:Escherichia coli overexpressing glutamate decarboxylase GadB can produce Gamma-Aminobutyric Acid with addition of monosodium glutamate. The yield and productivity of Gamma-Aminobutyric Acid might be significantly improved if the overexpressed GadB in E. coli cells can be excreted outside, where it can directly transforms monosodium glutamate to Gamma-Aminobutyric Acid. In this study, GadB was fused to signal peptides TorA or PelB, respectively, and overexpressed in E. coli BL21(DE3). It was found that TorA could facilitate GadB secretion much better than PelB. Conditions for GadB secretion and Gamma-Aminobutyric Acid production were optimized in E. coli BL21(DE3)/pET20b-torA-gadB, leading the secretion of more than half of the overexpressed GadB. Fed-batch fermentation for GadB expression and Gamma-Aminobutyric Acid production of BL21(DE3)/pET20b-torA-gadB was sequentially performed in one fermenter; 264.4 and 313.1 g/L Gamma-Aminobutyric Acid were obtained with addition of monosodium glutamate after 36 and 72 h, respectively.
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isolation and characterization of a gamma aminobutyric Acid producing strain lactobacillus buchneri wpz001 that could efficiently utilize xylose and corncob hydrolysate
Applied Microbiology and Biotechnology, 2015Co-Authors: Anqi Zhao, Xiaoqing Hu, Xiaoyuan WangAbstract:Lactobacillus buchneri strain WPZ001 that could efficiently produce Gamma-Aminobutyric Acid was isolated from Chinese fermented sausages. Optimal cultivation conditions for Gamma-Aminobutyric Acid production in L. buchneri WPZ001 were determined, and xylose was found to be the best carbon source. Using xylose as the sole carbon source, 70 g/L Gamma-Aminobutyric Acid was produced by flask fermentation of L. buchneri WPZ001 for 48 h, and the harvested cells could continue to convert monosodium glutamate to Gamma-Aminobutyric Acid in buffer and produce 59 g Gamma-Aminobutyric Acid after eight runs of biotransformation; the total yield of Gamma-Aminobutyric Acid reached 129 g/L. This combination strategy also worked well when the low-cost corncob hydrolysate was used as the sole carbon source, and the yield of Gamma-Aminobutyric Acid reached 117 g/L. The results indicate that L. buchneri WPZ001 has great potential for industrial production of Gamma-Aminobutyric Acid.
Anqi Zhao - One of the best experts on this subject based on the ideXlab platform.
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Metabolic engineering of Escherichia coli to produce Gamma-Aminobutyric Acid using xylose.
Applied microbiology and biotechnology, 2017Co-Authors: Anqi Zhao, Xiaoyuan WangAbstract:Biomass-derived xylose is an economically interesting substrate for the sustainable microbial production of value-added compounds. Escherichia coli could barely use xylose to directly produce Gamma-Aminobutyric Acid. In this study, E. coli strains that could directly produce Gamma-Aminobutyric Acid were developed through the deletion of eight genes sucA, puuE, gabT, gabP, xylA, xylB, waaC, and waaF, and the overexpression of two E. coli genes gadB and gdhA, as well as five Caulobacter crescent genes CcxylA, CcxylB, CcxylC, CcxylD, and CcxylX. Both E. coli strains W3110 and JM109 could directly produce Gamma-Aminobutyric Acid from xylose after either overexpression of the seven genes or deletion of the eight genes. Overexpression of the seven genes of in the multiple deletion mutants further increased Gamma-Aminobutyric Acid production. Among the 28 recombinant E. coli strains constructed in this study, the highest Gamma-Aminobutyric Acid was produced by JWZ08/pWZt7-g3/pWZt7-xyl. JWZ08/pWZt7-g3/pWZt7-xyl could produce 3.95 g/L Gamma-Aminobutyric Acid in flask cultivation, using xylose as the sole carbon source.
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Extracellular expression of glutamate decarboxylase B in Escherichia coli to improve Gamma-Aminobutyric Acid production.
AMB Express, 2016Co-Authors: Anqi Zhao, Cheng Chen, Xiaoyuan WangAbstract:Escherichia coli overexpressing glutamate decarboxylase GadB can produce Gamma-Aminobutyric Acid with addition of monosodium glutamate. The yield and productivity of Gamma-Aminobutyric Acid might be significantly improved if the overexpressed GadB in E. coli cells can be excreted outside, where it can directly transforms monosodium glutamate to Gamma-Aminobutyric Acid. In this study, GadB was fused to signal peptides TorA or PelB, respectively, and overexpressed in E. coli BL21(DE3). It was found that TorA could facilitate GadB secretion much better than PelB. Conditions for GadB secretion and Gamma-Aminobutyric Acid production were optimized in E. coli BL21(DE3)/pET20b-torA-gadB, leading the secretion of more than half of the overexpressed GadB. Fed-batch fermentation for GadB expression and Gamma-Aminobutyric Acid production of BL21(DE3)/pET20b-torA-gadB was sequentially performed in one fermenter; 264.4 and 313.1 g/L Gamma-Aminobutyric Acid were obtained with addition of monosodium glutamate after 36 and 72 h, respectively.
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isolation and characterization of a gamma aminobutyric Acid producing strain lactobacillus buchneri wpz001 that could efficiently utilize xylose and corncob hydrolysate
Applied Microbiology and Biotechnology, 2015Co-Authors: Anqi Zhao, Xiaoqing Hu, Xiaoyuan WangAbstract:Lactobacillus buchneri strain WPZ001 that could efficiently produce Gamma-Aminobutyric Acid was isolated from Chinese fermented sausages. Optimal cultivation conditions for Gamma-Aminobutyric Acid production in L. buchneri WPZ001 were determined, and xylose was found to be the best carbon source. Using xylose as the sole carbon source, 70 g/L Gamma-Aminobutyric Acid was produced by flask fermentation of L. buchneri WPZ001 for 48 h, and the harvested cells could continue to convert monosodium glutamate to Gamma-Aminobutyric Acid in buffer and produce 59 g Gamma-Aminobutyric Acid after eight runs of biotransformation; the total yield of Gamma-Aminobutyric Acid reached 129 g/L. This combination strategy also worked well when the low-cost corncob hydrolysate was used as the sole carbon source, and the yield of Gamma-Aminobutyric Acid reached 117 g/L. The results indicate that L. buchneri WPZ001 has great potential for industrial production of Gamma-Aminobutyric Acid.
David H Miller - One of the best experts on this subject based on the ideXlab platform.
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reduced gamma aminobutyric Acid concentration is associated with physical disability in progressive multiple sclerosis
Brain, 2015Co-Authors: Niamh Cawley, Bhavana S Solanky, Nils Muhlert, Richard Anthony Edward Edden, Claudia A M Wheelerkingshott, David H MillerAbstract:Neurodegeneration is thought to be the major cause of ongoing, irreversible disability in progressive stages of multiple sclerosis. Gamma-Aminobutyric Acid is the principle inhibitory neurotransmitter in the brain. The aims of this study were to investigate if Gamma-Aminobutyric Acid levels (i) are abnormal in patients with secondary progressive multiple sclerosis compared with healthy controls; and (ii) correlate with physical and cognitive performance in this patient population. Thirty patients with secondary progressive multiple sclerosis and 17 healthy control subjects underwent single-voxel MEGA-PRESS (MEscher-GArwood Point RESolved Spectroscopy) magnetic resonance spectroscopy at 3 T, to quantify Gamma-Aminobutyric Acid levels in the prefrontal cortex, right hippocampus and left sensorimotor cortex. All subjects were assessed clinically and underwent a cognitive assessment. Multiple linear regression models were used to compare differences in Gamma-Aminobutyric Acid concentrations between patients and controls adjusting for age, gender and tissue fractions within each spectroscopic voxel. Regression was used to examine the relationships between the cognitive function and physical disability scores specific for these regions with gamma-aminobuytric Acid levels, adjusting for age, gender, and total N-acetyl-aspartate and glutamine-glutamate complex levels. When compared with controls, patients performed significantly worse on all motor and sensory tests, and were cognitively impaired in processing speed and verbal memory. Patients had significantly lower Gamma-Aminobutyric Acid levels in the hippocampus (adjusted difference = -0.403 mM, 95% confidence intervals -0.792, -0.014, P = 0.043) and sensorimotor cortex (adjusted difference = -0.385 mM, 95% confidence intervals -0.667, -0.104, P = 0.009) compared with controls. In patients, reduced motor function in the right upper and lower limb was associated with lower Gamma-Aminobutyric Acid concentration in the sensorimotor cortex. Specifically for each unit decrease in Gamma-Aminobutyric Acid levels (in mM), there was a predicted -10.86 (95% confidence intervals -16.786 to -4.482) decrease in grip strength (kg force) (P < 0.001) and -8.74 (95% confidence intervals -13.943 to -3.015) decrease in muscle strength (P < 0.006). This study suggests that reduced Gamma-Aminobutyric Acid levels reflect pathological abnormalities that may play a role in determining physical disability. These abnormalities may include decreases in the pre- and postsynaptic components of Gamma-Aminobutyric Acid neurotransmission and in the density of inhibitory neurons. Additionally, the reduced Gamma-Aminobutyric Acid concentration may contribute to the neurodegenerative process, resulting in increased firing of axons, with consequent increased energy demands, which may lead to neuroaxonal degeneration and loss of the compensatory mechanisms that maintain motor function. This study supports the idea that modulation of Gamma-Aminobutyric Acid neurotransmission may be an important target for neuroprotection in multiple sclerosis.See De Stefano and Giorgio (doi:10.1093/brain/awv213) for a scientific commentary on this article.
Song Tao - One of the best experts on this subject based on the ideXlab platform.
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The effects of chronic repetitive transcranial magnetic stimulation on glutamate and Gamma-Aminobutyric Acid in rat brain.
Brain research, 2009Co-Authors: Li Yue, Huo Xiaolin, Song TaoAbstract:Recent studies have shown that repetitive transcranial magnetic stimulation (rTMS) has therapeutic potential for some neurological and psychiatric disorders. However, the neurobiological effects of this tool are not sufficiently explained so far, previous research reported that rTMS can change dopamine release, there have been few studies to examine a possible effect of rTMS on amino Acid neurotransmitter. This study aimed to determine the effects of chronic rTMS on glutamate and Gamma-Aminobutyric Acid concentration in the rat brain. Sprague–Dawley rat was subject to 500 pulses of 0.5 Hz rTMS for 15 days, or sham stimulation. After last stimulation, glutamate and Gamma-Aminobutyric Acid content were measured by high performance liquid chromatography (HPLC). Results showed that the content of glutamate and Gamma-Aminobutyric Acid increased significantly in hippocampus and striatum after chronic rTMS, but reduced significantly in the hypothalamus. These results indicate that chronic rTMS has a modulatory effect on the glutamate and Gamma-Aminobutyric Acid systems. This change in amino Acid neurotransmitter may contribute to its beneficial effects.
Nils Muhlert - One of the best experts on this subject based on the ideXlab platform.
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reduced gamma aminobutyric Acid concentration is associated with physical disability in progressive multiple sclerosis
Brain, 2015Co-Authors: Niamh Cawley, Bhavana S Solanky, Nils Muhlert, Richard Anthony Edward Edden, Claudia A M Wheelerkingshott, David H MillerAbstract:Neurodegeneration is thought to be the major cause of ongoing, irreversible disability in progressive stages of multiple sclerosis. Gamma-Aminobutyric Acid is the principle inhibitory neurotransmitter in the brain. The aims of this study were to investigate if Gamma-Aminobutyric Acid levels (i) are abnormal in patients with secondary progressive multiple sclerosis compared with healthy controls; and (ii) correlate with physical and cognitive performance in this patient population. Thirty patients with secondary progressive multiple sclerosis and 17 healthy control subjects underwent single-voxel MEGA-PRESS (MEscher-GArwood Point RESolved Spectroscopy) magnetic resonance spectroscopy at 3 T, to quantify Gamma-Aminobutyric Acid levels in the prefrontal cortex, right hippocampus and left sensorimotor cortex. All subjects were assessed clinically and underwent a cognitive assessment. Multiple linear regression models were used to compare differences in Gamma-Aminobutyric Acid concentrations between patients and controls adjusting for age, gender and tissue fractions within each spectroscopic voxel. Regression was used to examine the relationships between the cognitive function and physical disability scores specific for these regions with gamma-aminobuytric Acid levels, adjusting for age, gender, and total N-acetyl-aspartate and glutamine-glutamate complex levels. When compared with controls, patients performed significantly worse on all motor and sensory tests, and were cognitively impaired in processing speed and verbal memory. Patients had significantly lower Gamma-Aminobutyric Acid levels in the hippocampus (adjusted difference = -0.403 mM, 95% confidence intervals -0.792, -0.014, P = 0.043) and sensorimotor cortex (adjusted difference = -0.385 mM, 95% confidence intervals -0.667, -0.104, P = 0.009) compared with controls. In patients, reduced motor function in the right upper and lower limb was associated with lower Gamma-Aminobutyric Acid concentration in the sensorimotor cortex. Specifically for each unit decrease in Gamma-Aminobutyric Acid levels (in mM), there was a predicted -10.86 (95% confidence intervals -16.786 to -4.482) decrease in grip strength (kg force) (P < 0.001) and -8.74 (95% confidence intervals -13.943 to -3.015) decrease in muscle strength (P < 0.006). This study suggests that reduced Gamma-Aminobutyric Acid levels reflect pathological abnormalities that may play a role in determining physical disability. These abnormalities may include decreases in the pre- and postsynaptic components of Gamma-Aminobutyric Acid neurotransmission and in the density of inhibitory neurons. Additionally, the reduced Gamma-Aminobutyric Acid concentration may contribute to the neurodegenerative process, resulting in increased firing of axons, with consequent increased energy demands, which may lead to neuroaxonal degeneration and loss of the compensatory mechanisms that maintain motor function. This study supports the idea that modulation of Gamma-Aminobutyric Acid neurotransmission may be an important target for neuroprotection in multiple sclerosis.See De Stefano and Giorgio (doi:10.1093/brain/awv213) for a scientific commentary on this article.
