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BACKGROUND: This study investigated the effects of γ‐aminobutyric acid (GABA) combined with ultrasonic stress germination (AUG) treatment on the phenolic content and antioxidant activity of highland barley (HB). Key variables, including germination times (ranging from 0 to 96 h), ultrasonic power (200–500 W), and GABA concentration (5–20 mmol/L), were optimized using response surface methodology (RSM) to enhance the enrichment of phenolic compounds. Furthermore, the study assessed the content, composition, and antioxidant activities of phenolic compounds in HB under various treatment conditions such as germination alone (G), ultrasonic stress germination (UG), and AUG treatment. RESULTS: The study identified optimal conditions for the phenolic enrichment of HB, which included a germination time of 60 h, an ultrasound power of 300 W, and a GABA concentration of 15 mmol L−1. Under these conditions, the total phenolic content (TPC) in HB was measured at 7.73 milligrams of gallic acid equivalents per gram dry weight (mg GAE/g DW), representing a 34.96% enhancement compared to untreated HB. Notably, all treatment modalities – G, UG, and AUG – significantly increased the phenolic content and antioxidant activity in HB, with the AUG treatment proving to be the most effective. CONCLUSION: These obtained results suggest that AUG treatment is a promising processing method for enriching phenolic compounds and improving antioxidant activity in HB. Subsequently, the AUG‐treated HB can be used to develop phenolic‐rich germinated functional foods to further broaden the application of HB. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The circular aquaculture model of largemouth bass pond engineering has the characteristics of high yield and efficiency, but it is prone to stress caused by flow velocity and density, which affects the yield of largemouth bass (Micropterus salmoides). γ‐Aminobutyric acid (GABA) is believed to have the effect of improving growth and stress tolerance. We divided the largemouth bass into three groups: a control group, a flow rate and density combined stress group, and a combined stress feed supplemented with GABA (0.9%) group, and conducted a 60‐day aquaculture experiment. The results showed that the final weight, weight gain rate (WGR), specific growth rate (SGR), and feed efficiency (FE) of largemouth bass significantly decreased in the combined stress group (P < 0.05). The serum aspartate aminotransferase (AST), alanine transaminase (ALT) activity, and glucose (GLU), malondialdehyde (MDA) level of largemouth bass significantly higher than the control group, and the serum lysozyme (LZM) activity and total antioxidant capacity (T‐AOC) were significantly lower than the control group (P < 0.05). After adding GABA, the final weight, WGR, SGR, and FE decreased, and the serum GLU levels, AST, ALT activity, and MDA levels were downregulated, and the serum LZM activity and T‐AOC of largemouth bass were upregulated. But most of the above are still at the level of the control group. Under combined stress, the messenger ribonucleic acid (mRNA) expression levels of growth hormone (GH), insulin‐like growth factor‐Ⅰ (IGF‐I), B‐cell lymphoma‐2 (Blc2), nuclear transcription factor E2‐related factor 2 (Nrf2), catalase (CAT), and superoxide dismutase (SOD) genes were significantly reduced (P < 0.05), while the mRNA expression levels of heat stress protein 70 (HSP70), heat stress protein 90 (HSP90), nuclear factor kappa‐B (NF‐κB), interleukin‐1β (IL‐1β), Bax and keap1 genes were significantly increased (P < 0.05). After the exogenous addition of GABA, all the above genes have a certain degree of callback, but GH, HSP70, HSP90, IL‐1β, Bax, Nrf2, CAT, and SOD have not yet reached the level of the control group. These results indicate that adding GABA to feed can alleviate the adverse effects of combined stress of flow rate and density to a certain extent and provide insights for solving the problems in the circular aquaculture model of largemouth bass. [ABSTRACT FROM AUTHOR]

The γ-aminobutyric acid (GABA) is a widely distributed neurotransmitter in living organisms, known for its inhibitory role in animals. GABA exerts calming effects on the mind, lowers blood pressure in animals, and enhances stress resistance during the growth and development of plants. Enhancing GABA content in plants has become a focal point of current research. In plants, GABA is synthesized through two metabolic pathways, the GABA shunt and the polyamine degradation pathway, with the GABA shunt being the primary route. Extensive studies have investigated the regulatory mechanisms governing GABA synthesis. At the genetic level, GABA production and degradation can be modulated by gene overexpression, signaling molecule-induced expression, transcription factor regulation, and RNA interference. Additionally, at the level of transporter proteins, increased activity of GABA transporters and proline transporters enhances the transport of glutamate and GABA. The activity of glutamate decarboxylase, a key enzyme in GABA synthesis, along with various external factors, also influences GABA synthesis. This paper summarizes the biological functions, metabolic pathways, and regulatory mechanisms of GABA, providing a theoretical foundation for further research on GABA in plants. [ABSTRACT FROM AUTHOR]

Phenibut is a gamma aminobutyric acid derivative with activity at γ‐aminobutyric acid (GABA)B, A and β‐phenethylamine receptors. It was developed as a drug in the former Soviet Union to overcome anxiety and improve cognitive function in military personnel. In the last decade, it has made inroads into the European and U.S. markets, being marketed for purported nootropic properties. Here, we summarize the current knowledge on phenibut, its toxicology, pharmacology, adverse health effects, and patterns of use. Publications in peer‐reviewed journals were searched in PubMed, Web of Science, and Google Scholar databases. Available literature points to adverse side effects associated with intoxication, withdrawal, and addiction to phenibut. Some of these effects can be life‐threatening, requiring hospitalization and therapeutic interventions. Supportive efforts are often complicated by a lack of knowledge regarding phenibut's toxicology and pharmacology. Ingestion of phenibut was often associated with concomitant use of other substances of abuse. As control over its online marketing seems unrealistic, current efforts need to be focused on the addition of phenibut to current drug screening tests and the development of generally accepted treatment strategies for phenibut‐associated toxicities. [ABSTRACT FROM AUTHOR]

Rice is an important food crop worldwide but is usually susceptible to saline stress. When grown on soil with excessive salt, rice plants experience osmotic, ionic, and oxidative stresses that adversely affect growth performance. γ-Aminobutyric acid (GABA) is a nonproteinogenic amino acid that plays an important role in the metabolic activities of organisms. Glutamate decarboxylase (GAD) is the rate-limiting enzyme in GABA metabolism. Here, we genetically modified rice GAD by overexpression or CRISPR-mediated genome editing. These lines, named gad3-ox1 and gad3-ox2 or gad1/3-ko, were used to explore the effects of endogenous GABA accumulation on salt tolerance in rice. Both the gad3-ox1 and gad3-ox2 lines exhibited significant accumulation of the GABA content, whereas the gad1/3-ko line presented a reduced GABA content in vivo. Notably, the two overexpression lines were markedly resistant to salt stress compared with the wild-type and knockout lines. Furthermore, our results demonstrated that endogenous GABA accumulation in the gad3-ox1 and gad3-ox2 lines increased the contents of antioxidant substances and osmotic regulators, decreased the content of membrane lipid peroxidation products and the Na+ content, and resulted in strong tolerance to salt stress. Together, these data provide a theoretical basis for cultivating rice varieties with strong salt tolerance. [ABSTRACT FROM AUTHOR]

Summary Soil nitrogen (N) significantly influences the interaction between plants and pathogens, yet its impact on host defenses and pathogen strategies via alterations in plant metabolism remains unclear. Through metabolic and genetic studies, this research demonstrates that high‐N‐input exacerbates tomato bacterial wilt by altering γ‐aminobutyric acid (GABA) metabolism of host plants. Under high‐N conditions, the nitrate sensor NIN‐like protein 7 (SlNLP7) promotes the glutamate decarboxylase 2/4 (SlGAD2/4) transcription and GABA synthesis by directly binding to the promoters of SlGAD2/4. The tomato plants with enhanced GABA levels showed stronger immune responses but remained susceptible to Ralstonia solanacearum. This led to the discovery that GABA produced by the host actually heightens the pathogen's virulence. We identified the R. solanacearum LysR‐type transcriptional regulator OxyR protein, which senses host‐derived GABA and, upon interaction, triggers a response involving protein dimerization that enhances the pathogen's oxidative stress tolerance by activating the expression of catalase (katE/katGa). These findings reveal GABA's dual role in activating host immunity and enhancing pathogen tolerance to oxidative stress, highlighting the complex relationship between tomato plants and R. solanacearum, influenced by soil N status. [ABSTRACT FROM AUTHOR]

Halomonas elongata OUT30018 is a moderately halophilic bacterium that synthesizes and accumulates ectoine as an osmolyte by activities of the enzymes encoded by the high salinity-inducible ectABC operon. Previously, we engineered a γ-aminobutyric acid (GABA)-producing H. elongata GOP-Gad (ΔectABC::mCherry-HopGadmut) from an ectoine-deficient mutant of this strain due to its ability to use high-salinity biomass waste as substrate. Here, to further increase GABA accumulation, we deleted gabT, which encodes GABA aminotransferase (GABA-AT) that catalyzes the first step of the GABA catabolic pathway, from the H. elongata GOP-Gad genome. The resulting strain H. elongata ZN3 (ΔectABC::mCherry-HopGadmut ΔgabT) accumulated 291 µmol/g cell dry weight (CDW) of GABA in the cells, which is a 1.5-fold increase from H. elongata GOP-Gad's 190 µmol/g CDW. This result has confirmed the role of GABA-AT in the GABA catabolic pathway. However, redundancy in endogenous GABA-AT activity was detected in a growth test, where a gabT-deletion mutant of H. elongata OUT30018 was cultured in a medium containing GABA as the sole carbon and nitrogen sources. Because L-2,4-diaminobutyric acid aminotransferase (DABA-AT), encoded by an ectB gene of the ectABC operon, shares sequence similarity with GABA-AT, a complementation analysis of the gabT and the ectB genes was performed in the H. elongata ZN3 genetic background to test the involvement of DABA-AT in the redundancy of GABA-AT activity. Our results indicate that the expression of DABA-AT can restore GABA-AT activity in H. elongata ZN3 and establish DABA-AT's aminotransferase activity toward GABA in vivo. [ABSTRACT FROM AUTHOR]

Cold stress adversely affects rice growth, particularly at the early vegetative growth stage. In higher plants, nitrogen metabolism plays a central role in amino acid metabolism, plant defense mechanisms and productivity. This report investigated the effects of cold stress and supplemental γ-aminobutyric acid (GABA) under cold stress on nitrogen metabolism in rice seedlings. Cold stress resulted in a greater increase in the transformation to NH4+ by nitrate reductase (NR) in roots, it further resulted in lower levels of NO3 - content in roots, weakened glutamine glutamate (GOGAT/GS) pathway and elevated glutamate dehydrogenase (GDH) pathway of rice seedlings. Whereas, compared with cold stress, supplementation of GABA (2.5 mmol·L-1) could increase relative water content (79.43%) and biomass (34.15%) of rice seedlings. GABA could act as an amplifier of stress signal conduction/transduction to increase NR activity and promote NO3 - assimilation in leaves. In addition, GABA elicited the Ca2+ signaling pathway which could promote the GDH pathway and GABA shunt, increase the activities of GS and GDH, and the expression of OsGAD2 and OsGDH family. The GABA might increase the ratio of the Glu family and avoid NH4+ toxicity in order to raise the concentration of organic compounds and alleviate the harmful consequences of cold stress. Based on these observations, this study proposed that GABA mediated cold tolerance in rice seedlings by activating Ca2+ burst and subsequent crosstalk among Ca2+ signaling, GDH pathway and GABA shunt. [ABSTRACT FROM AUTHOR]

The risk of cardiovascular disease (CVD) is approximately doubled in subjects with hypercholesterolemia compared to those with normal blood cholesterol levels. Monacolin K (MK), the main active substance in rice fermented by the Monascus purpureus, acts on cholesterol metabolism. Rice also contains other bioactive compounds such as γ-oryzanol (OZ) and γ-aminobutyric acid (GABA). In a randomized, placebo-controlled, double-blind trial, the efficacy and tolerability of a food supplement (FS) based on an ingredient standardized to contain monacolins (4.5%), OZ, and GABA were evaluated in subjects with mild dyslipidemia. For the duration of the trial, enrolled subjects (n = 44, each group) received the FS or placebo and were instructed to use an isocaloric diet. Compared to the placebo group, after a 3 months of the FS, the mean low-density lipoprotein cholesterol and mean TC values were reduced by 19.3 and 8.3%, respectively, while the mean high-density lipoprotein cholesterol value increased by 29.3%. On average, the subjects shifted from very high to moderate CVD risk. Glucose metabolism and hepatic and renal parameters did not change after the treatment and no adverse events were reported. Guidelines to handle hypercholesterolemia with food supplements in specific clinical settings are needed to better manage mild dyslipidemia. [ABSTRACT FROM AUTHOR]

Simple Summary: Previous studies in several species have demonstrated that dietary γ-aminobutyric acid (GABA) supplemented can improve the growth performance, immunity, and antioxidant activity of animals. However, the effects of GABA on growing minks are not well documented. Therefore, this study aimed to evaluate the effects of GABA on growth performance, immunity, and intestinal microbiota in growing minks, and to determine the optimal level of GABA supplementation for their development. The present experiment was conducted to investigate the effects of γ-aminobutyric acid (GABA) on the growth performance, immunity, antioxidant capacity, and intestinal microbiota of growing minks. One hundred minks were evenly allocated across five groups, with each group consisting of 10 males and 10 females. The minks in these groups were fed a basal diet supplemented with γ-aminobutyric acid (GABA) at 0 (control), 10, 20, 30, and 40 mg/kg of diet, respectively. The experiment lasted for eight weeks. The results showed that GABA significantly affected immunity, antioxidant capacity, and intestinal microbiota (p < 0.05). Compared to the control minks, minks in 20, 30, and 40 mg/kg GABA group had greater total protein quantitative (TP), immunoglobulin A (IgA), immunoglobulin M (IgM) content, total antioxidant capacity (T-AOC), and glutathione peroxidase (GSH-Px) activities in serum as well as interleukin-4 (IL-4) level in jejunal mucosa (p < 0.05), and had less serum blood urea nitrogen (BUN) content (p < 0.05). Furthermore, compared with the control, the supplementation of GABA at 30 mg/kg of diet improved average daily feed intake (ADFI) (p < 0.05), increased immunoglobulin G (IgG) content in serum, interleukin-10 (IL-10) and secreted immunoglobulin A (SIgA) levels in jejunal mucosa, and decreased jejunal mucosal interleukin-2 (IL-2), interleukin-12 (IL-12), and interferon-γ (IFN-γ) levels (p < 0.05). The weight and feed intake of males were higher than females, and the feed/gain ratio (F/G) was lower than females (p < 0.05). Males also had greater serum superoxide dismutase (SOD) and GSH-Px activities, and jejunal mucosa IL-2, IL-4, IL-12, SIgA, and IFN-γ levels (p < 0.05), and males had less serum IgA, IgM, and T-AOC contents, and jejunal mucosal tumor necrosis factor-α (TNF-α) level (p < 0.05). The results suggest that the supplementation of GABA at 30 mg/kg of diet can improve immune status and antioxidant capacity, and modulate the intestinal microbiota abundance of growing minks. [ABSTRACT FROM AUTHOR]

Hemp seed protein (HSP), a by-product of hemp oil processing, was converted into a functional protein ingredient enriched with γ-aminobutyric acid (GABA) and peptides through a two-step microbial fermentation process. To enhance peptide and free amino acid production from HSP, it was hydrolyzed using alkaline protease produced by Bacillus subtilis HA. The HSP was hydrolyzed at a degree of 40% at 55 °C for 24 h, yielding a pH of 6.55, an acidity of 1.22%, and 205.45 mg% tyrosine equivalents. This process resulted in the production of low molecular-weight peptides. (<5000 Da) The total amino acid content and branched-chain amino acids (leucine, isoleucine, and valine) were 6.78 mg/g and 1.47 mg/g. Subsequently, the production of γ-aminobutyric acid (GABA) in the HSP hydrolysate was optimized through co-fermentation with lactic acid bacteria in the presence of 5% MSG at 30 °C for 5 days. The serial co-fermented HSP hydrolysate exhibited a GABA content of 33.98 mg/g and a viable bacterial count of 9.51 log CFU/mL for Lb. plantarum KS2020. This serial co-fermentation process, combining proteolysis and lactic acid fermentation, not only increased the peptide content but also promoted GABA accumulation, positioning HSP hydrolysate as a promising candidate for functional foods with potential health benefits. [ABSTRACT FROM AUTHOR]

In order to investigate the important functional-active components in different varieties of natto, natto was processed using soybean, black bean, red bean, mung bean, lentil, chickpea, kidney bean, pea, red bean and cowpea, and the differences of nattokinase, polyphenol, natto polysaccharide and γ-aminobutyric acid were compared and analyzed in these natto. The results showed that the nattokinase activity ranged from 985.31 to 2453.18 U/g, and the nattokinase activity in chickpea natto was significantly higher than those of other natto (P

In order to explore the influence of sugar treatment on the enrichment of γ-aminobutyric acid (GABA) in peanut sprouts, this paper selected the optimal application concentration of different types of exogenous sugars (mannose, sucrose and glucose). The effects of GABA on the germination of peanut seeds and the related substances of GABA anabolic metabolism were investigated and the possible mechanism of action was studied. The results showed that mannose, sucrose and glucose treatment could significantly (P

Abstract Rose flowers (Rosa hybrida L.) are highly perishable and have a limited vase life. This study evaluated the effects of preharvest foliar applications of γ-aminobutyric acid (GABA) and calcium chloride (CaCl2), individually and combined, on antioxidant responses and vase life of cut Jumilia rose flowers. Treatments included foliar sprays of GABA at 0, 20, 40, and 60 mM and CaCl2 at 0, 0.75%, and 1.5%, applied in a factorial design within a completely randomized setup before harvest. Results showed GABA and CaCl2 interaction (especially, 60 mM GABA and 1.5% CaCl2) significantly increased enzymatic antioxidants including superoxide dismutase, catalase, and peroxidase, as well as non-enzymatic antioxidants such as flavonoids, carotenoids, phenolics, and antioxidant activity in petals compared to control. SOD activity in roses, treated with CaCl2 (1.5%) and GABA (60 mM), peaked at 7.86 units. mg−1 protein min−1, showing a nearly 2.93-fold increase over the control (2.68 units. mg−1 protein min−1). A parallel trend was observed for CAT activity. These treatments also reduced petal malondialdehyde content and polyphenol oxidase activity. Protein content and vase life duration increased in all treatments. Plants treated with a combination of GABA (20 mM) and CaCl2 (0.75%), GABA (60 mM) and CaCl2 (1.5%), or GABA (40 mM) individually exhibited the longest vase life duration. The co-application of GABA and CaCl2 improved the antioxidant activity and postharvest quality of cut roses by reducing PPO activity and MDA contents, increasing protein content and prolonging vase life. This treatment is a potential postharvest strategy to improve antioxidant capacity and delay senescence in cut roses.

Abstract Background and aims To investigate the clinical features, ALDH5A1 gene variations, treatment, and prognosis of patients with succinic semialdehyde dehydrogenase (SSADH) deficiency. Materials and methods This retrospective study evaluated the findings in 13 Chinese patients with SSADH deficiency admitted to the Pediatric Department of Peking University First Hospital from September 2013 to September 2023. Results Thirteen patients (seven male and six female patients; two sibling sisters) had the symptoms aged from 1 month to 1 year. Their urine 4-hydroxybutyrate acid levels were elevated and were accompanied by mildly increased serum lactate levels. Brain magnetic resonance imaging (MRI) showed symmetric abnormal signals in both sides of the globus pallidus and other areas. All 13 patients had psychomotor retardation, with seven showing epileptic seizures. Among the 18 variants of the ALDH5A1 gene identified in these 13 patients, six were previously reported, while 12 were novel variants. Among the 12 novel variants, three (c.85_116del, c.206_222dup, c.762C > G) were pathogenic variants; five (c.427delA, c.515G > A, c.637C > T, c.755G > T, c.1274T > C) were likely pathogenic; and the remaining four (c.454G > C, c.479C > T, c.1480G > A, c.1501G > C) were variants of uncertain significance. The patients received drugs such as L-carnitine, vigabatrin, and taurine, along with symptomatic treatment. Their urine 4-hydroxybutyric acid levels showed variable degrees of reduction. Conclusions A cohort of 13 cases with early-onset SSADH deficiency was analyzed. Onset of symptoms occurred from 1 month to 1 year of age. Twelve novel variants of the ALDH5A1 gene were identified.

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Avocado (Persea americana Mill.) is a subtropical climacteric fruit with a limited shelf life due to its high sensitivity to low temperatures. Chilling injury (CI) produced by cold storage displays symptoms in avocado fruit such as irregular ripening, darkening of the mesocarp, hardening of vascular strands, lipid oxidation with "off flavors", and pitting and darkening of the skin, increasing weight loss. Accordingly, we studied the effect of γ-aminobutyric acid (GABA) and 1-methylcyclopropene (1-MCP) alone or in combination as postharvest treatments to maintain quality and to increase cold tolerance. Hass avocados were stored at 5 °C plus 5 days at room temperature. The results showed that the combined treatment improved fruit quality parameters as compared with control fruit and with those treated with only 1-MCP or GABA. The combined treatment delayed synergistically the postharvest ripening process. This delayed pattern was concomitant with a delayed ethylene pattern in GABA + 1-MCP or 1-MCP fruit batches. CI symptoms and electrolyte leakage were minimized in all GABA and 1-MCP fruit batches specifically in the combined treatment. For this reason, the synergistic effect of the combination of treatments may be recommended as an effective alternative strategy to prolong the postharvest quality of avocado during refrigerated storage. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] Identification of single nucleotide polymorphisms (SNPs) and candidate genes significantly associated with the content of γ-aminobutyric acid (GABA) in rice grains may provide a theoretical basis for further exploring the molecular mechanism of GABA enrichment in rice grains, and lay the foundation for cultivating high-GABA content varieties. [Method] This study performed genome-wide association studies (GWAS) for GABA content with re-sequencing in 139 early japonica rice core germplasm resources in Northwest China. The candidate genes were screened based on haplotype analysis and gene annotation, and expression pattern of candidate genes were analyzed by expression profile database and fluorescence quantitative PCR. [Result] GABA content in grains showed abundant variation with a coefficient of variation of 31.25%. Genome-wide association analysis showed a total of 6 significant and representative SNPs on chromosomes 6, 8, 9, 11 and 12 were detected, and OsBADH2 and OsGABA-T2, which have been cloned in relation to GABA content. In addition, six candidate genes were predicted for GABA content in the rice grains, among which LOC_Os09g10720 was identified as highlight candidate gene, and the feasibility of its involvement in the decomposition of GABA in rice grains was further verified. [Conclusion] A total of 6 SNPs significantly associated with GABA content in rice grain are detected. And 6 candidate genes that might be associated with GABA content are screened out, they are LOC_Os09g09750, LOC_Os09g09760, LOC_Os09g10210, LOC_Os09g09820, LOC_Os09g10280 and LOC_ Os09g10720. Among them, LOC_Os09g10720 was used as a focus candidate gene. [ABSTRACT FROM AUTHOR]

Pickled tea is an anaerobically fermented tea common in Thailand, Myanmar and Yunnan minority areas. γ-aminobutyric acid (GABA) is non-protein amino acid with multiple bioactives, which can be easily produced under anaerobic conditions. During the processing of pickled tea, controlling the process parameters is effective for the production of GABA-rich products; however, the precise parameters remain to be clarified. In the present study, the fresh leaves of Camellia sinensis (L.) Kuntze (C. sinensis) 'FudingDabai', C. sinensis 'MabianLv No. 1', C. sinensis 'Wuniuzao' and C. sinensis 'Fuxuan No. 9' were used as raw materials to process GABA-rich pickled tea. Single-factor and orthogonal experiments were conducted to determine the best tea cultivars and optimize the best processing parameters via comparing the content of GABA, tea polyphenols (TPs) and other biochemical components of GABA-rich pickled tea. The results of the signal-factor experiment showed that the fresh leaves of C. sinensis 'MabianLv No. 1' had the highest GABA content of 2.61 mg·g−1 after treatment with vacuum for 6 h; therefore, C. sinensis 'MabianLv No. 1' was selected as the raw material for the subsequent experiments. Orthogonal experiments showed that the highest GABA content of 2.53 mg·g−1 was found in the pickled tea with 8 h of vacuum treatment, 20 min of rolling after microwave fixing, 20 min of spreading and 20 d of anaerobic fermentation at room temperature. Further, the sensory evaluation showed that it possesses a strong sour taste with a slight sweetness and a light yellow color and better comprehensive quality. This indicates that these parameters are optimal for the processing of GABA-rich pickled tea. This study will provide scientific basis for the subsequent production of high GABA tea. [ABSTRACT FROM AUTHOR]

Sleeplessness (insomnia) is a potential symptom of depression. A probiotic NVP1704 alleviates depression-like behavior and neuroinflammation in mice. Therefore, to understand whether NVP1704 could be effective against sleeplessness in vivo , we exposed immobilization stress (IS) in mice, then orally administered NVP1704 for 5 days, and assayed depression/anxiety-like behavior in the open field, elevated plus maze, and tail suspension tests, sleeping latency time, and sleep duration, euthanized then by exposure to CO2, and analyzed their related biomarkers. Oral administration of NVP1704 decreased IS-induced depression/anxiety-like behavior and sleeping latency time and increased IS-suppressed sleeping duration. NVP1704 increased IS-suppressed expression of γ-aminobutyric acid (GABA), GABAA receptor α1 (GABAARα1) and α2 subunits (GABAARα2), serotonin, 5-HT receptors (5-HT1AR and 5-HT1BR), and melatonin receptors (MT1R and MT2R) in the prefrontal cortex and thalamus. NVP1704 also increased the IS-suppressed GABAARα1-positive cell population in the prefrontal cortex and decreased IS-induced corticosterone, TNF-α, and IL-6 expression and the NF-κB+Iba1+ cell population in the brain and myeloperoxidase, TNF-α, and IL-6 expression and the NF-κB+CD11c+ cell population in the colon. Based on these findings, NVP1704 may alleviate depression/anxiety/sleeplessness-like behaviors through the upregulation of serotonergic and GABAergic systems and downregulation of NF-κB activation. [ABSTRACT FROM AUTHOR]

In order to explore the influence of sugar treatment on the enrichment of γ-aminobutyric acid (GABA) in peanut sprouts, this paper selected the optimal application concentration of different types of exogenous sugars (mannose, sucrose and glucose). The effects of GABA on the germination of peanut seeds and the related substances of GABA anabolic metabolism were investigated and the possible mechanism of action was studied. The results showed that mannose, sucrose and glucose treatment could significantly (P<0.05) increase the content of GABA in peanut sprouts, and the activity of glutamate decarboxylase (GAD), diamine oxidase (DAO), polyamine oxidase (PAO) and the contents of glutamic acid, putrescine, spermidine and spermidine were significantly changed in oxidase (P<0.05). At the same time, according to the test results, different exogenous sugar treatments could increase the contents of ascorbic acid, protein and resveratrol in peanut sprouts to different degrees. GABA in peanut sprouts can be enriched by exogenous sugar treatment, and its influence mechanism may be GABA branch and polyamine degradation pathway. [ABSTRACT FROM AUTHOR]

In order to investigate the important functional-active components in different varieties of natto, natto was processed using soybean, black bean, red bean, mung bean, lentil, chickpea, kidney bean, pea, red bean and cowpea, and the differences of nattokinase, polyphenol, natto polysaccharide and γ-aminobutyric acid were compared and analyzed in these natto. The results showed that the nattokinase activity ranged from 985.31 to 2453.18 U/g, and the nattokinase activity in chickpea natto was significantly higher than those of other natto (P<0.05). The total phenol content ranged from 1.44 to 3.21 mg GAE/g, and the total phenolic acid content ranged from 19.754 to 183.902 μg/g. The types of phenolic substances were abundant in black bean natto, mung bean natto and cowpea natto. The yield of polysaccharide was 1.03%-15.11%, the content of total sugar was 21.86%-58.40%, and the content of uronic acid was 4.26%-15.09%. And the yield of polysaccharide, the contents of total sugar and uronic acid in kidney bean natto were significantly higher than those of other natto (P<0.05). The content of γ-aminobutyric acid was 4.97-15.99 mg/g, and the content of γ-aminobutyric acid in cowpea natto was significantly higher than those of other natto (P<0.05). The viable number of Bacillus subtilis natto in lentil natto was significantly higher than those of other natto (P<0.05). After comprehensive evaluation, black bean, cowpea and kidney bean were ideal raw materials for the produce of new natto. [ABSTRACT FROM AUTHOR]

Quinoa, a dicotyledonous annual herb belonging to the subfamily Amaranthaceae, has remarkable resistance to cold, drought, and barren conditions. However, few studies have reported on quinoa root metabolism under waterlogging stress. In this study, quinoa strains were treated with waterlogging, and the control group was exposed to normal water management conditions; waterlog-resistant (Dianli-188) and waterlog-sensitive (Dianli-60) strains were selected. Ultra-high-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was used to analyze the root systems of four groups of quinoa seedlings (Dianli-60 treatment group: TR4; Dianli-60 control group: CR4; Dianli-188 treatment group: TR5; Dianli-188 control group: CR5). In total, 1044 metabolites were detected. Kyoto Encyclopedia of Genes and Genomes analysis was used to identify 648 differential metabolites involved in biosynthesis. In addition, we found that alanine, aspartate, and glutamate metabolism and glycolysis, tricarboxylic cycle, and butanoate metabolism pathways were related to the synthesis of γ-aminobutyric acid (GABA). The metabolites of C5-branched dibasic acid metabolism, urea cycle, starch and sucrose metabolism, phenolic metabolism, and flavonoid biosynthesis pathways were found to participate in the waterlogging stress response. Sucrose, glucose, and trehalose provide sufficient energy for adventitious root production. GABA regulates phenylpropane metabolism, including regulation of phenolic acids and flavonoids to enhance the antioxidant capacity of quinoa in response to waterlogging stress. This study provided a theoretical basis for breeding quinoa waterlog-resistant varieties, we can screen waterlogging-resistant strains based on the content of these metabolites in future. Thereby accelerating the breeding process of quinoa. [ABSTRACT FROM AUTHOR]

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Recently, there has been a renewed interest in the fermentation of kefir grains using fruit-based substrates, such as coconut water. Kefir grains contain a mixture of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast, which have important probiotic capacity and play a vital role in improving the nutritional and functional properties of the new product being developed. The principal objective of this study was to determine the functional properties of the microorganisms identified and characterized from kefir, CWK, and sourdough fermented with coconut water kefir (CWKS), such as Limosilactobacillus fermentum, Lactiplantibacillus plantarum, L. fusant, L. reuteri, L. kunkeei, Acetobacter aceti, A. lovaniensis, A. pasteurianus, Candida kefyr, Rhodotorula mucilaginosa, Saccharomyces cerevisiae, C. guilliermondii, and C. colliculosa. In addition to identifying functional properties, such as glutamic acid production, phytase production, phytic acid degradation, and exopolysaccharide production, from this study, it was found that significantly high quantities of glutamic acid, exopolysaccharide, and phytase enzyme were detected in two LAB isolates, Limosilactobacillus fermentum and Lactiplantibacillus plantarum. [ABSTRACT FROM AUTHOR]

Type 2 diabetes mellitus (T2DM) is the most prevalent metabolic disease in the world and has become a global epidemic health problem. A legume-based diet can help prevent and control the onset and development of T2DM. To study the health effects of rich γ-aminobutyric acid (GABA) adzuki beans, this study, through the establishment of the T2DM model, analyzed the level of glucose and lipid metabolism and related indexes of liver function in mice with GABA-rich adzuki beans. Results showed that the high dose of GABArich adzuki beans (TF3) had a certain effect on the resistance to overweight, and could significantly reduce the level of fasting blood glucose (P < 0.05), restore the body's ability to regulate blood glucose, and alleviate insulin resistance. Compared with the M group, the levels of total cholesterol, triglyceride, alanine transaminase, aspartate transaminase, urea, and creatinine in the serum of T2DM mice were reduced to different degrees in each treatment group, and TF3 and the positive control group had better effects on balancing blood glucose and regulating liver and kidney injury of T2DM mice and could alleviate the pathological injury of liver, pancreas and cecum tissue caused by high-fat diet. Results indicated that a diet rich in GABA adzuki beans could improve the level of small glucose and lipid metabolism, and alleviate the pathological injury of liver, pancreas and cecum tissue, providing a theoretical basis for the development and application of GABA-rich functional foods. [ABSTRACT FROM AUTHOR]

Given the link between excessive salt consumption and hypertension, reducing salt levels in bread, an important staple food in Japan, is essential. γ-Aminobutyric acid (GABA) has a salty taste-enhancing effect in vivo, and its production is influenced by the type of spice extract in vitro. However, the effects of spices on GABA levels, total free amino acid composition, and taste quality in whole-wheat bread remain unclear. Therefore, this study aimed to investigate whether the addition of spice extracts, which do not affect bread flavor and taste, can increase the GABA level in low-salt whole-wheat bread and whether free amino acid content affects the taste quality of bread using an automatic home bread maker. Through free amino acid composition analysis and sensory testing, we evaluated the influence of six spice extracts on the composition of free amino acids, including GABA, in whole-wheat bread. We found that cumin and anise extracts were effective in increasing the GABA level to approximately twice that in whole-wheat bread. Moreover, both the preference and saltiness of the bread were favorable, indicating that these extracts are useful for reducing the salt content of whole-wheat bread. This study provides a theoretical basis for guiding industrial production. [ABSTRACT FROM AUTHOR]

Background: Dysfunctional sensory gating in anxiety disorders, indexed by the failure to inhibit the P50 event-related potential (ERP) to repeated stimuli, has been linked to deficits in the major inhibitory neurotransmitter γ-aminobutyric acid (GABA). Aims/Methods: This study, conducted in 30 healthy volunteers, examined the acute effects of GABAA (lorazepam: 1 mg) and GABAB receptor (baclofen: 10 mg) agonists on P50 measures of auditory sensory gating within a paired-stimulus (S1-S2) paradigm and assessed changes in gating in relation to self-ratings of anxiety. Results: Compared to placebo, lorazepam reduced ERP indices of sensory gating by attenuating response to S1. Although not directly impacting P50 inhibition, baclofen-induced changes in gating (relative to placebo) were negatively correlated with trait but not state anxiety. Conclusions: These preliminary findings support the involvement of GABA in sensory gating and tentatively suggest a role for GABAB receptor signaling in anxiety-associated gating dysregulation. [ABSTRACT FROM AUTHOR]

Purpose: TRPV1 is a nonselective Ca2+ channel protein that is widely expressed and plays an important role during the occurrence and development of many cancers. Activation of TRPV1 channels can affect tumour progression by regulating proliferation, apoptosis and migration. Some studies have also shown that activating TRPV1 can affect tumour progression by modulating tumour immunity. However, the effects of TRPV1 on the development of non-small cell lung cancer (NSCLC) have not been explored clearly. Method: The Cancer Genome Atlas (TCGA) database and spatial transcriptomics datasets from 10 × Genomics were used to analyze TRPV1 expression in various tumour tissues. Cell proliferation and apoptosis were examined by cell counting kit 8 (CCK8), colony formation, and flow cytometry. Immunohistochemistry, qPCR, and western blotting were used to determine the mRNA and protein expression levels of TRPV1 and other related molecules. Tumour xenografts in BALB/C and C57BL/6J mice were used to determine the effects of TRPV1 on NSCLC development in vivo. Neurotransmitter content was examined by LC-MS/MS, ELISA and Immunohistochemistry. Immune cell infiltration was assessed by flow cytometry. Results: In this study, we found that TRPV1 expression was significantly upregulated in NSCLC and that patients with high TRPV1 expression had a poor prognosis. TRPV1 knockdown can significantly inhibit NSCLC proliferation and induce cell apoptosis through Ca2+-IGF1R signaling. In addition, TRPV1 knockdown resulted in increased infiltration of CD4+ T cells, CD8+ T cells, GZMB+CD8+ T cells and DCs and decreased infiltration of immunosuppressive MDSCs in NSCLC. In addition, TRPV1 knockout effectively decreased the expression of M2 macrophage markers CD163 and increased the expression of M1-associated, costimulatory markers CD86. Knockdown or knockout of TRPV1 significantly inhibit tumour growth and promoted an antitumour immune response through supressing γ-aminobutyric acid (GABA) secretion in NSCLC. Conclusion: Our study suggests that TRPV1 acts as a tumour promoter in NSCLC, mediating pro-proliferative and anti-apoptotic effects on NSCLC through IGF1R signaling and regulating GABA release to affect the tumour immune response. [ABSTRACT FROM AUTHOR]

γ-Aminobutyric acid (GABA) is a crucial neurotransmitter with wide application prospects. In this study, we focused on a GABA-producing strain from a traditional Chinese fermented beverage system. Among the six isolates, Lactobacillus hilgardii GZ2 exhibited the greatest ability to produce GABA in the traditional Chinese fermented beverage system. To increase GABA production, we optimized carbon sources, nitrogen sources, temperature, pH, and monosodium glutamate and glucose concentrations and conducted fed-batch fermentation. The best carbon and nitrogen sources for GABA production and cell growth were glucose, yeast extract and tryptone. Gradual increases in GABA were observed as the glucose and monosodium glutamate concentrations increased from 10 g/L to 50 g/L. During fed-batch fermentation, lactic acid was used to maintain the pH at 5.56, and after feeding with 0.03 g/mL glucose and 0.4 g/mL sodium glutamate for 72 h, the GABA yield reached 239 g/L. This novel high-GABA-producing strain holds great potential for the industrial production of GABA, as well as the development of health-promoting functional foods and medical fields. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gamma-aminobutyric acid (GABA) is a non-protein amino acid that is found in the brain and central nervous system of animals as an inhibitory neurotransmitter. It has been shown to have a variety of physiological functions, including stress reduction and immune enhancement. This study investigated the effects of dietary supplementation with GABA on growth, serum biochemistry, innate immunity, and disease resistance in juvenile olive flounders (Paralichthys olivaceus) challenged with Edwardsiella tarda under high-stocking density. A control diet and three experimental diets were prepared, with 150 mg/kg (GABA150), 200 mg/kg (GABA200), and 250 mg/kg (GABA250) of GABA added to each diet, respectively. Each experimental diet was fed to olive flounders in triplicate with an initial weight of 12.75 g ± 0.3 g in 40 L tanks at two stocking densities: normal density (20 fish/tank) and high density (40 fish/tank). After 8 weeks of the feeding trial, growth, feed utilization, whole-body proximate compositions, blood analyses, and non-specific immune responses were measured, and challenge tests were performed. There were no significant differences in the weight gain (WG) and specific growth rate (SGR) among fish fed the GABA-supplemented diets at the two stocking densities. However, the normal-density groups showed significantly higher WG and SGR than the high-density groups (p < 0.05). There was no significant difference in feed efficiency and protein efficiency ratio among all groups. Moreover, there was no significant difference in the whole-body proximate composition analysis (p > 0.05). There were no significant differences in cortisol levels in fish fed the GABA at both densities, but the high-density group showed a significantly higher cortisol than the low-density group. Blood GABA significantly increased in a dose-dependent manner regardless of the density groups (p < 0.05). Superoxide dismutase activity showed significantly higher levels than the control group, but there was no significant effect of the stocking densities in fish fed the GABA diets (p < 0.05). Myeloperoxidase activities in fish fed the GABA200 and GABA250 diets showed significantly higher levels at both of the stocking densities (p < 0.05). Lysozyme activity was significantly higher in the GABA150 group than in the CON, GABA200, and GABA250 groups (p < 0.05). After 15 days of challenge tests with Edwardsiella tarda, the cumulative survival rates of the GABA150, GABA200, and GABA250 groups were significantly higher than that of the CON group (p < 0.05). The results suggested that the optimal dietary GABA level for juvenile olive flounder culture is 150 mg/kg, regardless of rearing density, to enhance growth, immunity, and disease resistance. [ABSTRACT FROM AUTHOR]

Mesiotemporal lobe epilepsy is the most refractory form of epilepsy. The management of this condition relies on the use of antiepileptic drugs known to provide symptomatic relief. Herbal remedies are therefore an alternative to finding a cure for epilepsy. The present study aimed to assess the antiepileptic and anti-amnesic effects of Sida corymbosa aqueous extract using the pentylenetetrazole (PTZ) kindling model in rats. For this, 48 rats were divided into 6 groups of 8 animals each and treated as follows: normal and negative controls received per os (p.o) distilled water (10 mL/kg); experimental groups received S. corymbosa extract (17.14, 34.28, and 68.56 mg/kg, p.o); and positive control group received levetiracetam (250 mg/kg, p.o). One hour after the treatments, animals intraperitoneally (i.p) received a subconvulsive dose of PTZ (25 mg/kg), except the normal control group. The animals were treated once daily until the onset of the first tonic-clonic seizure (stage 5) in the negative control group. Twenty-four hours following the onset of the first seizure, memory impairment was assessed. Twenty-four hours later, the animals were sacrificed, and the hippocampus and prefrontal cortex were collected for biochemical analyses. The extract (68.56 mg/kg) prevented (p

The prevailing opinion emphasizes fronto-parietal network (FPN) is key in mediating general fluid intelligence (gF). Meanwhile, recent studies show that human MT complex (hMT+), located at the occipito-temporal border and involved in 3D perception processing, also plays a key role in gF. However, the underlying mechanism is not clear, yet. To investigate this issue, our study targets visuo-spatial intelligence, which is considered to have high loading on gF. We use ultra-high field magnetic resonance spectroscopy (MRS) to measure GABA/Glu concentrations in hMT+ combining resting-state fMRI functional connectivity (FC), behavioral examinations including hMT+ perception suppression test and gF subtest in visuo-spatial component. Our findings show that both GABA in hMT+ and frontal-hMT+ functional connectivity significantly correlate with the performance of visuo-spatial intelligence. Further, serial mediation model demonstrates that the effect of hMT+ GABA on visuo-spatial gF is fully mediated by the hMT+ frontal FC. Together our findings highlight the importance in integrating sensory and frontal cortices in mediating the visuo-spatial component of general fluid intelligence.

This study aimed to assess the function of γ-aminobutyric acid (GABA) on growth performance, food intake and glucose homeostasis of Micropterus salmoides fed carbohydrate (CHO)-enriched diets. The intracerebroventricular glucose + GABA co-injected fish had higher cumulative food intake, and expression of orexigenic genes (ghrelin and neuropeptide y (npy)) in the brain than those of the single glucose-injected group. In the feeding trial, M. salmoides (10.35 ± 0.05 g) were fed four feeds containing a control feed (10 % CHO, C) and three GABA contents [0 (HC), 50 (HC-G1), and 100 (HC-G2) mg kg−1, respectively] of high-CHO feed (20 % CHO) for 12 weeks. High CHO prominently (P < 0.05) decreased WGR, SGR, FI, p-Ampk protein content, and expression of ghrelin, npy, fbpase, pparα, cpt1α and aco1 compared with the control group, but the opposite was true for plasma glucose and triglyceride levels, tissue glycogen and lipid contents, and expression of proopiomelanocortin, leptin a, gk, pk, gs, chrebp, srebp1, fas and acc1. HC-G2 diets prominently (P < 0.05) up-regulated WGR, SGR, FI, p-Ampk protein content, and expression of ghrelin, npy, gk, pk, chrebp, srebp1, fas and acc1 compared with the HC group. Also, HC-G2 diets increased glucose tolerance of M. salmoides fed high-CHO diets after glucose loading. Overall, GABA improved the growth performance, food intake and glucose homeostasis of high-CHO-fed fish by the increase of appetite, glycolysis, glycogenesis and lipolysis, as well as the inhibition of gluconeogenesis and lipid synthesis.

The role of the gut microbiota in the gut-brain axis has attracted attention in recent years. Some gut microbiota produces γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter in mammals, in vitro, but the correlation between gut microbiota composition and intestinal GABA concentration, as well as the action of intestinal GABA in vivo, are poorly understood. Herein, we found that the intestinal GABA concentration was increased in mice by the intervention of the gut microbiota with neomycin or Bifidobacterium bifidum TMC3115 (TMC3115). Administration of TMC3115 reduced anxiety without affecting serum levels of serotonin, corticosterone, or GABA. We further found that intestinal epithelial cells expressed GABA receptor subunits and mediated mitogen-activated protein kinase signaling upon GABA stimulation. In addition, administration of TMC3115 induced mitogen-activated protein kinase signaling in colonic epithelial cells but not in small intestinal epithelial cells in mice. These results indicate that GABA produced by the gut microbiota, mainly in the colon, may affect host behavioral characteristics via GABA receptors expressed in intestinal epithelial cells without being transferred to the blood. This study suggests a novel mechanism by which intestinal GABA exerts physiological effects, even in the presence of the blood-brain barrier.

Djulis (Chenopodium formosanum), a native plant of Taiwan, is esteemed for its rich nutritional profile, encompassing high levels of dietary fiber, proteins, essential amino acids, and microelements. This study delved into the influence of soaking and germinating conditions on the synthesis of γ-aminobutyric acid (GABA), total phenolic content (TPC), antioxidant activity, and enzymatic activity in djulis. Enrichment culture tests were conducted to ascertain optimal soaking conditions. Results revealed that soaking djulis seeds for 4 h at 25 °C before germination notably augmented GABA production. Furthermore, djulis seeds subjected to soaking and germination at 30 °C for 48 h exhibited heightened GABA and anthocyanin contents. Conversely, germination at 25 °C for 48 h demonstrated superior TPC and 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging activity. Optimal concentrations of glutamic acid, monosodium glutamate, pyridoxal-5′-phosphate (vitamin B6), Ca2+, and pH were found to enhance glutamine acid decarboxylase activity, consequently elevating GABA content. In summary, fine-tuning soaking and germinating conditions presents a promising avenue for augmenting GABA production in djulis, thereby bolstering its nutritional and functional utility. Future investigations aimed at elucidating the molecular mechanisms underlying enzymatic activity modulation during soaking and germination could yield valuable insights into optimizing GABA production.

Abstract Nickel (Ni) is a heavy metal that adversely affects the growth of different crops by inducing oxidative stress and nutrient imbalance. The role of rhizobacteria (RB) is vital to resolve this issue. They can promote root growth and facilitate the uptake of water and nutrients, resulting in better crop growth. On the other hand, γ-aminobutyric acid (GABA) can maintain the osmotic balance and scavenge the reactive oxygen species under stress conditions. However, the combined effect of GABA and RB has not been thoroughly explored to alleviate Ni toxicity, especially in fenugreek plants. Therefore, in the current pot study, four treatments, i.e., control, A. fabrum (RB), 0.40 mM GABA, and 0.40 mM GABA + RB, were applied under 0Ni and 80 mg Ni/kg soil (80Ni) stress. Results showed that RB + 0.40 mM GABA caused significant improvements in shoot length (~ 13%), shoot fresh weight (~ 47%), shoot dry weight (~ 47%), root length (~ 13%), root fresh weight (~ 60%), and root dry weight (~ 15%) over control under 80 Ni toxicity. A significant enhancement in total chlorophyll (~ 14%), photosynthetic rate (~ 17%), stomatal CO2 concentration (~ 19%), leaves and roots N (~ 10 and ~ 37%), P (~ 18 and ~ 7%) and K (~ 11 and ~ 30%) concentrations, while a decrease in Ni (~ 83 and ~ 49%) concentration also confirmed the effectiveness of RB + 0.40 mM GABA than control under 80Ni. In conclusion, fabrum + 0.40 mM GABA can potentially alleviate the Ni toxicity in fenugreek plants. The implications of these findings extend to agricultural practices, environmental remediation efforts, nutritional security, and ecological impact. Further research is recommended to elucidate the underlying mechanisms, assess long-term effects, and determine the practical feasibility of using A. fabrum + 0.40GABA to improve growth in different crops under Ni toxicity.

Adaptation of plants to stress factors occurs with the participation of stress phytohormones, signaling network and plant neurotransmitters. Among the latter, in particular, γ-aminobutyric acid (γ-aminobutyric acid – GABA) is a non-proteinogenic four-carbon amino acid found in many prokaryotic and eukaryotic organisms. Its functions in plants have been actively studied only in the past decade. During this period, a lot of information has been accumulated about the protective effect of exogenous GABA on plants of various taxonomic groups under the influence of stress factors of various nature. The first national review is devoted to the analysis and generalization of data on the mechanisms of stress-protective action of GABA in plants. The ways of synthesis and metabolism of GABA in plant cells and the mechanisms of activation of these processes under stressful conditions are described. It is noted that the main way of GABA formation in plants is decarboxylation of glutamate by means of glutamate decarboxy­lase. Possible mechanisms of GABA reception and signal transmission to the genetic apparatus are discussed. Special attention is paid to the analysis of new data on the role of calcium in the activation of GABA synthesis and the realization of its physiological effects. Possible mechanisms of GABA’s influence on the functioning of mitochondria, its role in maintaining redox homeostasis under stressful conditions are discussed. At the same time, data on the increase in the expression of genes encoding the catalytic subunit of NADPH oxidase under the influence of GABA are presented. Functional connections between GABA and nitric oxide as a signaling mediator are considered. The effect of exogenous GABA on the main protective reactions of plants is characte­rized: the state of the antioxidant system, the accumulation of multifunctional low-molecular protectors, the synthesis of dehydrins and chaperones. The data on the phenomeno­logy of the effects of GABA under the main abiotic stresses are presented: the effects of extreme temperatures, drought and salinity on plants. The prospects for the practical use of GABA as a compound that combines the functions of an energy metabolite and a signaling mediator are noted.

γ-aminobutyric acid (GABA) is a non-protein amino acid discovered in animals, plants, and microorganisms that was approved as the "new resource food" by the National Health Commission of the People's Republic of China (NHC) in 2009. It has a wide range of applications in food, medicine, feed, and other industries, and the research has grown increasingly popular in recent years. The paper reviews the bio-synthesis and metabolic processes of GABA, summarizes the methods of chemical synthesis, plant enrichment, and present GABA detection techniques, and discusses their advantages and limitations. Furthermore, the main physiological functions and mechanism of GABA are summarized, and GABA’s research and development trend is also presented, in order to provide reference for future research and application of GABA.

Soil salinization is a widespread abiotic stress in China and one of the most critical factors affecting agricultural production and food security. γ-Aminobutyric acid (GABA) is a non-protein amino acid widely found in vertebrates, plants, and microorganisms, regulating the nervous system as well as plant defense systems. Mulberry is rich in GABA and exhibits extensive adaptability to various environments. In this study, we explored the possibility of alleviating salinity and alkalinity stress in mulberry seedlings using GABA and elucidating the intrinsic mechanisms by which GABA enhances salt-alkaline tolerance in mulberry trees through transcriptomic sequencing analysis. The results showed that 1 mM exogenous GABA enhanced the activities of mulberry seeds under saline-alkali stress, significantly increased the activities of POD and CAT (P < 0.01), reduced the level of reactive oxygen species and the content of malondialdehyde in mulberry seedlings and facilitated the growth and development of adventitious roots of mulberry. Transcriptomic analysis showed that GABA promoted the development and growth of adventitious roots of mulberry under saline-alkali stress by regulating the synthesis and modification of the cell wall, phytohormone signal transduction, and the conversion of starch and monosaccharides. Furthermore, the expression of pathogen pattern recognition receptors on the cell membrane of mulberry root system cells increased, enhancing the defense ability of mulberry root system cells. It is suggested that MYB, PME, SBT, EXP, DIR, POD, and the ARR family of transcription factors could be used as the target genes for further in-depth research.

AbstractThis study utilized the Taguchi method to optimize the conditions for the hydrothermal extraction of γ-aminobutyric acid (GABA) from fermented mulberry leaves (FMLs) and evaluated the antioxidant capacity of FML extract powder (EP). Four extraction factors—the leaves-to-water ratio, temperature, duration, and pH—were considered, and a series of experiments were conducted in accordance with a Taguchi design. The results indicated that the optimal hydrothermal extraction conditions were a leaves-to-water ratio of 1:10, temperature of 100 °C, duration of 15 min, and pH of 4. Under these conditions, the GABA content of an FML infusion was 75.04 mg GABA/g EP. Further analysis revealed that the pH had the strongest impact on GABA extraction, with the corresponding signal/noise ratio ranging from 27.36 to 31.60. Additionally, experimental results for antioxidant capacity showed that the total phenolic and flavonoid content of the EP were 12.94 mg gallic acid equivalent/g EP and 81.77 mg quercetin equivalent/g EP, respectively. The IC50 values for ABTS and DPPH free-radical-scavenging ability were 0.58 mg/mL and 0.20 mg/mL, respectively. The reducing power of the EP was 81.69 mg vitamin C equivalent/g EP. These findings provide an important foundation for further applications of FMLs.

Nickel (Ni) is a heavy metal that adversely affects the growth of different crops by inducing oxidative stress and nutrient imbalance. The role of rhizobacteria (RB) is vital to resolve this issue. They can promote root growth and facilitate the uptake of water and nutrients, resulting in better crop growth. On the other hand, γ-aminobutyric acid (GABA) can maintain the osmotic balance and scavenge the reactive oxygen species under stress conditions. However, the combined effect of GABA and RB has not been thoroughly explored to alleviate Ni toxicity, especially in fenugreek plants. Therefore, in the current pot study, four treatments, i.e., control, A. fabrum (RB), 0.40 mM GABA, and 0.40 mM GABA + RB, were applied under 0Ni and 80 mg Ni/kg soil (80Ni) stress. Results showed that RB + 0.40 mM GABA caused significant improvements in shoot length (~ 13%), shoot fresh weight (~ 47%), shoot dry weight (~ 47%), root length (~ 13%), root fresh weight (~ 60%), and root dry weight (~ 15%) over control under 80 Ni toxicity. A significant enhancement in total chlorophyll (~ 14%), photosynthetic rate (~ 17%), stomatal CO2 concentration (~ 19%), leaves and roots N (~ 10 and ~ 37%), P (~ 18 and ~ 7%) and K (~ 11 and ~ 30%) concentrations, while a decrease in Ni (~ 83 and ~ 49%) concentration also confirmed the effectiveness of RB + 0.40 mM GABA than control under 80Ni. In conclusion, fabrum + 0.40 mM GABA can potentially alleviate the Ni toxicity in fenugreek plants. The implications of these findings extend to agricultural practices, environmental remediation efforts, nutritional security, and ecological impact. Further research is recommended to elucidate the underlying mechanisms, assess long-term effects, and determine the practical feasibility of using A. fabrum + 0.40GABA to improve growth in different crops under Ni toxicity. [ABSTRACT FROM AUTHOR]

Fresh-cut potatoes (Solanum tuberosum L.) are susceptible to browning and microbial contamination during storage. In this study, the effects of trans-2-hexenal (E2H), ascorbic acid (VC), dimethyl dicarbonate (DMDC), and the combined treatment of E2H, VC, and DMDC on quality deterioration in fresh-cut potatoes were investigated. The response surface methodology (RSM) demonstrated that E2H, VC, and DMDC concentrations of 0.010%, 0.65%, and 240 mg/L, respectively, were the optimum conditions for fresh-cut potato preservation. Further analysis showed that the combined treatment of E2H, VC, and DMDC was the most effective method of reducing quality deterioration in potatoes compared to the control and individual treatments. Furthermore, the combined treatment of E2H, VC, and DMDC could decrease the accumulation of reactive oxygen species (ROS) via improving antioxidant enzyme activities. Meanwhile, energy-metabolism-related enzyme activities and glutamate decarboxylase (GAD) activity were enhanced, while γ-aminobutyric acid transaminase (GABA-T) activity was reduced via the combined treatment of E2H, VC, and DMDC, which contributed to maintaining high energy levels and GABA content in potatoes. These findings suggested that the combined treatment of E2H, VC, and DMDC could protect membrane integrity through enhancing antioxidant capacity, energy levels, and GABA content to maintain quality in fresh-cut potatoes. [ABSTRACT FROM AUTHOR]

Introduction: Ganoderma lucidum (G. lucidum, Lingzhi) has long been listed as a premium tonic that can be used to improve restlessness, insomnia, and forgetfulness. We previously reported that a rat model of sporadic Alzheimer's disease (sAD) that was induced by an intracerebroventricular injection of streptozotocin (ICV-STZ) showed significant learning and cognitive deficits and sleep disturbances. Treatment with a G. lucidum spore extract with the sporoderm removed (RGLS) prevented learning and memory impairments in sAD model rats. Method: The present study was conducted to further elucidate the preventive action of RGLS on sleep disturbances in sAD rats by EEG analysis, immunofluorescence staining, HPLC-MS/MS and Western blot. Results: Treatment with 720 mg/kg RGLS for 14 days significantly improved the reduction of total sleep time, rapid eye movement (REM) sleep time, and non- REM sleep time in sAD rats. The novelty recognition experiment further confirmed that RGLS prevented cognitive impairments in sAD rats. We also found that RGLS inhibited the nuclear factor-κB (NF-κB)/Nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammatory pathway in the medial prefrontal cortex (mPFC) in sAD rats and ameliorated the lower activity of γ-aminobutyric acid (GABA)-ergic neurons in the parabrachial nucleus (PBN). Discussion: These results suggest that inhibiting the neuroinflammatory response in the mPFC may be a mechanism by which RGLS improves cognitive impairment. Additionally, improvements in PBN-GABAergic activity and the suppression of neuroinflammation in the mPFC in sAD rats might be a critical pathway to explain the preventive effects of RGLS on sleep disturbances in sAD. [ABSTRACT FROM AUTHOR]

AIM: To investigate the effects of the γ-aminobutyric acid (GABAergic) neural pathway from the anterior cingulate cortex (ACC) to the nucleus accumbens (NAc) on the regulation of irritable bowel syndrome (IBS) and its underlying mechanisms in mice. METHODS: (1) A C57BL/6J mice model of IBS was established by using chronic acute combing stress (CACS). The mice were divided into a normal group and an IBS group (n=8). The presence of IBSlike symptoms was determined through behavioural tests, an intestinal motility test and abdominal withdrawal reflex scores. (2) Fluorescence gold (FG) retrograde tracing and immunohistochemistry were used to investigate the ACC–NAc GABAergic neural pathway and to examine the activation of GABA in the ACC in IBS mice (n=8). (3) A total of 1. 5 µL of normal saline (NS), GABAA receptor antagonist bicuculline (BIC) or agonist isoguvacine hydrochloride (Isog) was administered via a preburied catheter into the NAc of mice in IBS and normal groups. The mice were randomly divided into three groups (n=8): NS group, BIC group and Isog group. IBS-like symptoms were assessed. (4) The mice were preinjected with AAV2/9-mDlx-iCre-WPRE-pA in the ACC and AAV2/2Retro Plus-hSyn-DIO-hM3D (Gq)-eGFP-WPRE-pA in the NAc and subsequently divided into four groups (n=8): NS (intraperitoneal injection)+NS (NAc microinjection) group, NS+BIC group, clozapine N-oxide (CNO)+NS group and CNO+BIC group. The mice who received AAV2/2RetrohSyn-DIO-hM4D (Gi)-EGFP-WPRE-pA in the NAc were randomly divided into three groups (n=8): NS+NS group, NS+ BIC group and CNO+NS group. Enzyme-linked immunosorbent assay (ELISA) was employed to estimate the expression levels of histamine and 5-hydroxytryptamine (5-HT) in colon tissue, and the effects of GABAergic neural pathways from ACC to NAc on IBS were studied. RESULTS: CACS induced IBS-like symptoms in mice. The results of FG retrograde tracing combined with fluorescence immunohistochemistry showed that GABA neurons of ACC could project to NAc. The injection of BIC in the NAc was found to significantly reduce anxiety-like behaviours, diarrheal symptoms and visceral hypersensitivity in the IBS mice (P<0. 05). Chemogenetic inhibition of the ACC-NAc GABAergic neurons ameliorated IBSlike symptoms in mice (P<0. 05). CONCLUSION: The GABAergic pathway of ACC-NAc might be involved in the regulation of IBS in mice, which may be related to the release of histamine and 5-HT in colon tissue. [ABSTRACT FROM AUTHOR]

Epilepsy development can be caused by impaired postsynaptic action of GABA that is mediated by altered expression of GABA-A receptors and cation-chloride cotransporters, KCC2 (K+/Cl– cotransporter 2) and NKCC1 (Na+/K+/Cl– cotransporter 1). In the present study, we analyzed the expression of GABA-A receptors, KCC2, and NKCC1 in the hippocampus of Krushinsky–Molodkina (KM) rats, genetically prone to audiogenic seizures (AGS), during the first few months of the postnatal development (at P15, P60, and P120). Wistar rats of the corresponding ages were used as the control groups. In the hippocampus of KM pups, we observed downregulation of both KCC2 and NKCC1; however, the expression of GABA-A receptor α1-subunit (GABAAR(α1)) was increased. Moreover, KCC2 was not detected in an abnormally broad region of the granular layer, indicating the Cl– imbalance and impaired GABA-mediated inhibition in postsynaptic targets of GABA. These results suggested a delayed maturation of the hippocampal GABAergic system in KM rats in comparison with Wistar rats. In adult KM rats (P120) with fully developed susceptibility to AGS, normalization of both KCC2 and NKCC1 expression and KCC2 phosphorylation in the hippocampus was revealed. In contrast, GABAAR(α1) expression was decreased. We supposed that lower expression of GABA-A receptors in the hippocampus of adult KM rats might contribute either to the establishment of increased convulsive readiness or to hyperexcitation of the hippocampus during audiogenic kindling. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effects of encapsulated γ -aminobutyric acid (GABA) on weaning stress, growth performance, antioxidation and neuropeptides in lambs. Forty-eight healthy 45 days Hu lambs with similar body weight [(26.14±1.40) kg] were randomly assigned into four groups: the control group (fed basal diet), treatment Ⅰ group (fed basal diet + 100 mg/d of GABA), treatment Ⅱ group (fed basal diet + 140 mg/d of GABA), and treatment Ⅲ group (fed basal diet + 180 mg/d of GABA). All lambs were weaned at 48 days of age (day 1 of experiment). Feed intake (FI) and body weight (BW) of the lambs were recorded during the test period, and blood was collected on -3, 1, 3, 7 d. The results showed that, ① added GABA could significantly affect the average daily weight gain of lambs (P<0.05), the time significantly affected the BW, ADG and ADFI of lambs (P<0.05), while added GABA was no difference on the growth performance of lambs (P>0.05). ② Added GABA × time had no effect on the growth performance of lambs (P>0.05), and the addition of encapsulated GABA decreased the MDA content and increased the GSH-Px level; time could significantly affect the contents of MDA and GSH-Px in serum (P<0.05) the MDA and GSH-Px contents showed a trend of increasing and then decreasing with the prolongation of time. ③ Added GABA could significantly reduced the contents of cholecystokinin (CCK) and neuropeptide Y (NPY) (P<0.05); time significantly affected serum CCK and NPY content (P<0.05), as time increased, the overall trend of NPY was increasing. ④ Added GABA could decreased norepinephrine (NE) and dopamine (DA) levels and elevated pentazocine levels. Norepinephrine levels generally tended to increase with time. In conclusion, the addition of encapsulated γ-aminobutyric acid to the diets can improve growth performance by increasing the antioxidant capacity and decreasing the excitability of the brain to alleviate weaning stress. The optimal amount of encapsulated γ-aminobutyric acid was 140 mg/d under the present experimental conditions. [ABSTRACT FROM AUTHOR]

This study investigated the main microbial groups characterizing the interior surface of oak barrels from different years (1890, 1895, 1920, 1975, 2008) used in the production of vino cotto. The yeasts were characterized for the following properties: γ-aminobutyric acid (GABA) production, antioxidant activity, air–liquid interfacial biofilm formation, and anthocyanin adsorption capacity. Community-level physiological profile analysis revealed that the microbial communities inside the barrels used the tested carbon sources in different manners. The following yeast species were identified: Millerozyma farinosa, Zygosaccharomyces bisporus, Wickerhamiella versatilis, Zygosaccharomyces bailii, Starmerella lactis-condensi, and Zygosaccharomyces rouxii. All the strains were able to produce GABA, and S. lactis-condensi, Z. bisporus and Z. rouxii were the highest producers (more than 600 mg/L). The Z. rouxii and Z. bailii strains showed the highest antioxidant activity. Only seven strains out of ten M. farinosa formed air–liquid interfacial biofilm. None of the M. farinosa strains adsorbed anthocyanins on their cell wall. The other strains adsorbed anthocyanins in a strain-dependent way, and the highest adsorption was observed for the W. versatilis strains. The yeasts isolated in this study could be used to increase the functional properties and the quality of fermented foods and beverages. [ABSTRACT FROM AUTHOR]