• Applied Microscopy
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• v.42 no.1
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• pp.9-16
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• 2012

The goal of this study was to identify neurotransmitters in endings (p-endings) presynaptic to low-threshold mechanoreceptive vibrissa afferents in the laminae III/IV of cat trigeminal caudal nucleus (Vc). Rapidly-adapting vibrissa afferents were intra-axonally labeled after electrophysiological identification, and postembedding immunogold staining with antisera against ${\gamma}$-aminobutyric acid (GABA) and glycine was performed, followed by quantitative ultrastructural analysis of p-endings presynaptic to the labeled vibrissa afferent terminals. Sixteen p-endings, which are presynaptic to the HRP-labeled vibrissa afferent terminals, were analyzed in this study: Eight p-endings (50%, 8/16) were immunopositive to GABA but immunonegative to glycine (GABA+ p-ending), and remaining 8 p-endings (50%, 8/16) exhibited immunoreactivity to both GABA and glycine. Bouton volume of the p-endings was not significantly different between the two groups. However, the p-endings differed from each other in relative content of GABA and glycine. These findings suggest that low-threshold mechanoreceptive information conveyed through vibrissa afferent at Vc is presynaptically modulated by GABA and/or glycine, and that degree of presynaptic modulation may differ among each vibrissa afferent terminal.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.6
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• pp.695-702
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• 2017

The sustained tonic currents ($I_{tonic}$) generated by ${\gamma}$-aminobutyric acid A receptors ($GABA_{A}Rs$) are implicated in diverse age-dependent brain functions. While various mechanisms regulating $I_{tonic}$ in the hippocampus are known, their combined role in $I_{tonic}$ regulation is not well understood in different age groups. In this study, we demonstrated that a developmental increase in GABA transporter (GAT) expression, combined with gradual decrease in $GABA_AR{\alpha}_5$ subunit, resulted in various $I_{tonic}$ in the dentate gyrus granule cells (DGGCs) of preadolescent rats. Both GAT-1 and GAT-3 expression gradually increased at infantile ($P_{6-8}$ and $P_{13-15}$) and juvenile ($P_{20-22}$ and $P_{27-29}$) stages, with stabilization observed thereafter in adolescents ($P_{34-36}$) and young adults ($P_{41-43}$). $I_{tonic}$ facilitation of a selective GAT-1 blocker (NO-711) was significantly less at $P_{6-8}$ than after $P_{13-15}$. The facilitation of $I_{tonic}$ by SNAP-5114, a GAT-3 inhibitor, was negligible in the absence of exogenous GABA at all tested ages. In contrast, $I_{tonic}$ in the presence of a nonselective GAT blocker (nipecotic acid, NPA) gradually decreased with age during the preadolescent period, which was mimicked by $I_{tonic}$ changes in the presence of exogenous GABA. $I_{tonic}$ sensitivity to L-655,708, a $GABA_AR{\alpha}_5$ subunit inverse agonist, gradually decreased during the preadolescent period in the presence of NPA or exogenous GABA. Finally, Western blot analysis showed that the expression of the $GABA_AR{\alpha}_5$ subunit in the dentate gyrus gradually decreased with age. Collectively, our results suggested that the $I_{tonic}$ regulation of altered GATs is under the final tune of $GABA_AR{\alpha}_5$ subunit activation in DGGCs at different ages.

• Korean Journal of Food Science and Technology
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• v.44 no.1
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• pp.41-47
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• 2012

Steeping and germination conditions were investigated in order to produce barley containing a high ${\gamma}$-aminobutyric acid (GABA) content, and the changes in GABA and nutritional components before and after germination were also evaluated in this study. Water absorption rates of three barleys increased alongside both steeping time and steeping temperature. The highest GABA contents of the three barleys, 10.4-14.1 mg/100 g, were obtained from the steeping condition of $25^{\circ}C$ for 24 hr. The GABA contents of germinated barleys ranged from 14.3 to 20.9 mg/100 g, increasing by 3.9 to 14.6 times compared with raw barley. The crude lipid, crude ash and total mineral contents were slightly decreased after germination. The major fatty acids of the three barleys before and after germination were linoleic and palmitic acids. ${\beta}$-glucan contents of three barleys were slightly decreased after germination.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.559-565
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• 2021

This study aimed to optimize gamma-aminobutyric acid (GABA) production by employing five strains of lactic acid bacteria (LAB) that were capable of high cell growth and GABA production using a modified synthetic medium. GABA production in the strains was qualitatively confirmed via detection of colored spots using thin layer chromatography. Lactobacillus plantarum SGL058 and Lactococcus lactis SGL027 were selected as the suitable strains for GABA production. The conditions of the carbon and nitrogen sources were determined as 5 g/l glucose (L. plantarum SGL058), 5 g/l lactose (L. lactis SGL027), 10 g/l yeast extract (L. plantarum SGL058), and 20 g/l yeast extract (L. lactis SGL027) for GABA production. The cell growth, monitored by optical density at 600 nm, was 5.93 for L. plantarum SGL058. This value was higher than the 3.04 produced by L. lactis SGL027 at 36 h using a 5-L fermenter. The highest concentration of GABA produced was 546.7 ㎍/ml by L. plantarum SGL058 and 404.6 ㎍/ml by L. lactis SGL027, representing a GABA conversion efficiency of (%, w/w) of 4.0% and 3.4%, respectively. The fermentation profiles of L. plantarum SGL058 and L. lactis SGL027 provide a basis for the utilization of LAB in GABA production using a basal synthetic medium.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.26-33
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• 2016

Dominant lactic acid bacteria (LAB) strains were isolated from traditional fermented foods to obtain rare ${\gamma}$-aminobutyric acid (GABA)-producing LAB. Out of 147 isolates, 23 strains that could produce GABA with 1% (w/v) L-monosodium glutamate (MSG) were first isolated. After further screening of these rare GABA-producing LAB by analysis of the glutamate decarboxylase and 16S rRNA gene sequences, Enterococcus faecium JK29 was isolated, and 1.56 mM of GABA was produced after 48 h cultivation in basic de Man, Rogosa, and Sharpe (MRS) medium. To enhance GABA production by E. faecium JK29, the culture conditions were optimized. When E. faecium JK29 was cultivated in optimized MRS medium containing 0.5% (w/v) sucrose and 2% (w/v) yeast extract with 0.5% (w/v) MSG, GABA production reached 14.86 mM after 48 h cultivation at initial conditions of pH 7.5 and $30^{\circ}C$.

• Journal of Dairy Science and Biotechnology
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• v.31 no.2
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• pp.143-152
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• 2013

Aminobutyric acid (GABA), a major inhibitory neurotransmitter in the central nervous system of animals, has several physiological effects including anti-hypertensive, diuretic, tranquilizing, and anti-stress properties, in humans. The purpose of this study was to investigate Lactobacillus plantarum K74, which was isolated from kimchi and selected as a strain with a high ability to produce GABA, to develop a new starter culture for fermented milk production. L. plantarum K74 produced $134.52{\mu}g/mL$ GABA in MRS broth containing 1% MSG, $212.27{\mu}g/mL$ GABA in MRS broth containing 2% MSG, and $234.63{\mu}g/mL$ GABA in MRS broth containing 3% MSG. The optimum growth temperature of L. plantarum K74 was $34^{\circ}C$, reaching a pH of 4.4 after 18 hours of growth. L. plantarum K74 was most sensitive to novobiocin out of 16 different antibiotics tested, and was most resistant to kanamycin and polymyxin B. L. plantarum K74 did not produce ${\beta}$-glucuronidase, a carcinogenic enzyme, and was comparatively tolerant to bile juice and low pH. Furthermore, it displayed resistance to Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus at rates of 54.9%, 46.3%, and 0.7%, respectively.

• Food Science and Preservation
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• v.24 no.2
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• pp.274-281
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• 2017

The optimization of lactic acid fermentation was conducted to produce an old antler fortified with functional ingredients. For the over-production of gamma aminobutyric acid (GABA), the extract of old antlers (OA) was fermented by Lactobacillus plantarum EJ2015 with 0.5% YE, 1.5% glucose, and 3.5% MSG at $30^{\circ}C$ for 7 days. The lactic acid fermented OA showed high viable cell counts of $2.0{\times}10^8CFU/mL$, pH 6.56 and 0.77% acidity after 7 days. Addition of Auricularia auricula-judae (AAJ) enhanced the cell growth of L. plantarum EJ2014, resulting in higher viable cell counts of $2.0{\times}10^9CFU/mL$ and acid production after fermentation for 1 day. In particular, acidity was greatly decreased after fermentation for 3 days and 1.4% GABA was produced by converting efficiently mono sodium glutamate as a substrate. Fermented OA/AAJ mixture indicated the reduced cytotoxicity compared with that of unfermented OA. The fermented OA/AAJ mixture indicated anti-inflammatory effect with less production of NO in microphage cells. The production of NO dropped to $17.75{\mu}M$ at 4 mg/mL, and to $5.58{\mu}M$ at 6 mg/mL old antler after fermentation. Thus, lactic acid fermented OA with AAJ could fortify GABA, probiotics and dietary fiber.

• Journal of Life Science
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• v.17 no.7 s.87
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• pp.970-975
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• 2007

For the screening of ${\gamma}-aminobutyric$ acid (CABA)-producing bacteria, 86 bacterial strains which produce GABA were isolated from Kimchi and Salted fisk .Among these, three strains designated AML15, AML45-1, AML72 with relatively high GABA productivity were selecled by thin layer chromatography (TLC). To elucidate the relationship between isolated strains and the genus Lactobacillus, their 16S rDNA sequence were examined. The result of their DNA sequences showed 99% similarity with Lactobacillus brevis ATCC 367. On the basis of the these results, isolated strains were identified as Lactobacillus brevis and designated L. brevis AML15. In order to determine the optimum conditions for GABA production, the isolated strains were cultivated in pyridoxal phosphate (PLP) and monosodium glutami. acid (MSG). Results showed that L. brevis AML15 had the highest CABA productivity with 10,424 $nM/{\mu}l$ concentration in MRS broth containing 5% (w/v) MSG and 10 ${\mu}M$ PLP at pH 5.0. The results imply that L. brevis AML15 has the potential to be developed as a strain for GABA hyper-production.

• Journal of Life Science
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• v.20 no.7
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• pp.1005-1011
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• 2010

$\gamma$-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system. GABA transporters (GATs) control extracellular GABA levels by reuptake of released GABA from the synaptic cleft. However, how GATs are regulated has not yet been elucidated. Here, we used the yeast two-hybrid system to identify the specific binding protein(s) that interacts with the carboxyl (C)-terminal region of GAT1, the major isoform in the brain and find a specific interaction with the ubiquitin-specific protease 14 (Usp14), a deubiquitinating enzyme. Usp14 protein bound to the tail region of GAT1 and GAT2 but not to other GAT members in the yeast two-hybrid assay. The C-terminal region of Usp14 is essential for interaction with GAT1. In addition, these proteins showed specific interactions in the glutathione S-transferase (GST) pull-down assay. An antibody to GAT1 specifically co-immunoprecipitated Usp14 from mouse brain extracts. These results suggest that Usp14 may regulate the number of GAT1 at the cell surface.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.247-253
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• 2022

This study was conducted to investigate the effects of γ-aminobutyric acid (GABA) and a probiotic mixture on egg quality, blood parameters, and corticosterone content in broiler breeder stock in summer in Korea. A total of 72 broiler breeders (Arbor Acres) at 49 weeks old were randomly divided into the following three groups of 24 heads each: control, GABA, and probiotics (1 × 10⁸/g Bacillus licheniformis, 1 × 10⁷/g Lactiplantibacillus plantaru, and 1 × 10⁷/g Clostridium butyricum). The hens were fed a diet containing 50 mg of GABA/kg of feed and 0.1% probiotics for 6 weeks. Egg quality, blood parameters, and stress levels (corticosterone concentration) of the broiler breeders were evaluated. No significant differences were observed in the egg weight, albumen height, Haugh units, yolk color, shell thickness, or shell strength between the groups. There were no significant between-group differences in the blood biochemical profile, including total cholesterol, triglyceride, glucose, total protein, aspartate aminotransferase, alanine aminotransferase, albumin, and inorganic phosphorus concentrations. The corticosterone concentration was significantly lower in the GABA and probiotics groups than the control group (P < 0.05) at 6 weeks of age. In conclusion, these results suggest that dietary probiotics and GABA significantly improve the stress levels of broiler breeders in summer in Korea.