Glutamic Decarboxylase Research Articles

Islet autoantibody frequency in relatives of children with type 1 diabetes who have a type 2 diabetes diagnosis.

This study aimed to evaluate characteristics of autoimmunity in individuals who have a type 2 diagnosis and are relatives of children with type 1 diabetes. Pre-diagnosis samples (median 17 months before onset) from relatives who were later diagnosed with type 2 diabetes were measured for autoantibodies to glutamate decarboxylase 65 (GADA), islet antigen-2 (IA-2A), zinc transporter 8 (ZnT8A) and insulin (IAA) as well as the type 1 diabetes genetic risk score (GRS2). Associations between islet autoantibodies, insulin treatment and GRS2 were analysed using Fisher's exact and t-tests. Among 226 relatives (64% men; mean age at sampling 41 years; mean age 54 years at diagnosis), 32 (14%) were islet autoantibody-positive for at least one autoantibody more than a decade before diagnosis. Approximately half of these (n = 15) were treated with insulin. GADA-positivity was higher in insulin-treated relatives than in non-insulin-treated relatives (12/18 [67%] vs. 6/18 [33%], p < 0.001). IAA-positivity was observed in 13/32 (41%) of relatives with autoantibodies. GRS2 scores were increased in autoantibody-positive relatives (p = 0.032), but there was no clear evidence for a difference according to treatment (p = 0.072). This study highlights the importance of measuring islet autoantibodies, including IAA, in relatives of people with type 1 diabetes to avoid misdiagnosis.

Genome-wide identification and expression analysis of the GAD family reveal their involved in embryogenesis and hormones responses in Dimocarpus longan Lour.

Glutamate decarboxylase (GAD) is involved in GABA metabolism and plays an essential regulatory role in plant growth, abiotic stresses, and hormone response. This study investigated the expression mechanism of the GAD family during longan early somatic embryogenesis (SE) and identified 6 GAD genes based on the longan genome. Homology analysis indicated that DlGAD genes had a closer relationship with dicotyledonous plants. The analysis of cis-acting elements in the promoter region suggests that the GAD genes were associated with various stress responses and hormones. RNA sequencing (RNA-Seq) and the qRT-PCR data indicated that most DlGAD genes were highly expressed in the incomplete compact pro-embryogenic cultures (ICpEC) and upregulated in longan embryogenic callus (EC) after treatments with 2,4-D, high temperature (35 °C), IAA, and ABA. Moreover, the RNA-Seq analysis also revealed that DlGADs exhibit different expression patterns in various tissues and organs. The subcellular localization results showed that DlGAD5 was localized in the cytoplasm, suggesting that it played a role in the cytoplasm. Transient overexpression of DlGAD5 enhanced the expression levels of DlGADs and increased the activity of glutamate decarboxylase in longan embryogenic callus (EC), while the content of glutamic acid decreased. Thus, the DlGAD gene can play an important role in the early somatic embryogenesis of longan by responding to hormones such as IAA and ABA. DlGAD5 can affect the growth and development of longan by stimulating the expression of the DlGAD gene family, thereby increasing the GAD activity in the early SE of longan, participating in hormone synthesis and signaling pathways.

Glucose transporter-2 regulation of VMN GABA neuron metabolic sensor and transmitter gene expression

Glucose transporter-2 (GLUT2) monitors cellular glucose uptake. Astrocyte GLUT2 controls glucose counterregulatory hormone secretion. In vivo gene silencing and laser-catapult-microdissection tools were used here to investigate whether ventromedial hypothalamic nucleus (VMN) GLUT2 may regulate dorsomedial (VMNdm) and/or ventrolateral (VMNvl) γ-aminobutyric acid (GABA) neurotransmission to control this endocrine outflow in female rats. VMN GLUT2 gene knockdown suppressed or stimulated hypoglycemia-associated glutamate decarboxylase (GAD)1 and GAD2 mRNA expression in VMNdm versus VMNvl GABAergic neurons, respectively. GLUT2 siRNA pretreatment also modified co-expressed transmitter marker gene profiles in each cell population. VMNdm GABA neurons exhibited GLUT2 knockdown-sensitive up-regulated 5’-AMP-activated protein kinase-alpha1 (AMPKα1) and -alpha2 (AMPKα2) transcripts during hypoglycemia. Hypoglycemic augmentation of VMNvl GABA neuron AMPKα2 was refractory to GLUT2 siRNA. GLUT2 siRNA blunted (VMNdm) or exacerbated (VMNvl) hypoglycemic stimulation of GABAergic neuron steroidogenic factor-1 (SF-1) mRNA. Results infer that VMNdm and VMNvl GABA neurons may exhibit divergent, GLUT2-dependent GABA neurotransmission patterns in the hypoglycemic female rat. Data also document differential GLUT2 regulation of VMNdm versus VMNvl GABA nerve cell SF-1 gene expression. Evidence for intensification of hypoglycemic hypercorticosteronemia and -glucagonemia by GLUT2 siRNA infers that VMN GLUT2 function imposes an inhibitory tone on these hormone profiles in this sex.

Paeonol and glycyrrhizic acid in combination ameliorate the recurrent nitroglycerin-induced migraine-like phenotype in rats by regulating the GABBR2/TRPM8/PRKACA/TRPV1 pathway

Ethnopharmacological relevancePaeonol (PAE) and glycyrrhizic acid (GLY) are predominate components of 14 blood-entering ones of Piantongtang No. 1, which is a traditional Chinese medicine prescription for chronic migraine with minimal side effects. Both paeonol and glycyrrhizic acid exhibit analgesic, neuroprotective and anti-inflammatory properties individually. Our previous research has highlighted their combined effect (PAE + GLY) in ameliorating migraine symptoms. However, there are not yet any studies exploring the mechanism of action of PAE + GLY in the treatment of migraine. Aim of the studyThis research aimed to determine the mechanism of PAE + GLY in ameliorating the recurrent nitroglycerin-induced migraine-like phenotype in rats. Materials and methodsUsing a nitroglycerin-induced migraine model via subcutaneous injection in the neck, we evaluated the effect of PAE + GLY on migraine-like symptoms. Behavioural tests and biomarkers analysis were employed, alongside transcriptome sequencing (RNA-seq). Mechanistic insights were further verified utilising reverse transcription quantitative PCR (RT-qPCR), Western blot (WB), ELISA and immunofluorescence (IF) techniques. ResultsFollowing treatment with PAE + GLY, hyperalgesia threshold and 5-hydroxytryptamine (5-HT) levels increased, and migraine-like head scratching, histamine and calcitonin gene-related peptide (CGRP) levels were reduced. RNA-Seq experiments revealed that PAE + GLY upregulated the expression of Glutamate decarboxylase 2 (GAD2) and γ-aminobutyric acid type B receptor subunit 2 (GABBR2) genes. This upregulation activated the GABAergic synapse pathway, effectively inhibiting migraine attacks. Further validation demonstrated an increase in γ-aminobutyric acid (GABA) content in cerebrospinal fluid post PAE + GLY treatment, coupled with increased expression of dural GAD2, GABBR2 and transient receptor potential channel M8 (TRPM8). Consequently, this inhibited the expression of dural cAMP-dependent protein kinase catalytic subunit alpha (PRKACA) and transient receptor potential channel type 1 (TRPV1), subsequently downregulating p-ERK1/2, p-AKT1, IL-1β and TNF-α. ConclusionsOur findings underscore that PAE + GLY ameliorates inflammatory hyperalgesia migraine by upregulating inhibitory neurotransmitters and modulating the GABBR2/TRPM8/PRKACA/TRPV1 pathway.

Comprehensive characterization of γ-aminobutyric acid (GABA) production by Levilactobacillus brevis CRL 2013: insights from physiology, genomics, and proteomics.

Levilactobacillus brevis CRL 2013, a plant-derived lactic acid bacterium (LAB) with immunomodulatory properties, has emerged as an efficient producer of γ-aminobutyric acid (GABA). Notably, not all LAB possess the ability to produce GABA, highlighting the importance of specific genetic and environmental conditions for GABA synthesis. This study aimed to elucidate the intriguing GABA-producing machinery of L. brevis CRL 2013 and support its potential for safe application through comprehensive genome analysis. A comprehensive genome analysis of L. brevis CRL 2013 was performed to identify the presence of antibiotic resistance genes, virulence markers, and genes associated with the glutamate decarboxylase system, which is essential for GABA biosynthesis. Then, an optimized chemically defined culture medium (CDM) was supplemented with monosodium glutamate (MSG) and yeast extract (YE) to analyze their influence on GABA production. Proteomic and transcriptional analyses were conducted to assess changes in protein and gene expression related to GABA production. The absence of antibiotic resistance genes and virulence markers in the genome of L. brevis CRL 2013 supports its safety for potential probiotic applications. Genes encoding the glutamate decarboxylase system, including two gad genes (gadA and gadB) and the glutamate antiporter gene (gadC), were identified. The gadB gene is located adjacent to gadC, while gadA resides separately on the chromosome. The transcriptional regulator gadR was found upstream of gadC, with transcriptional analyses demonstrating cotranscription of gadR with gadC. Although MSG supplementation alone did not activate GABA synthesis, the addition of YE significantly enhanced GABA production in the optimized CDM containing glutamate. Proteomic analysis revealed minimal differences between MSG-supplemented and non-supplemented CDM cultures, whereas YE supplementation resulted in significant proteomic changes, including upregulation of GadB. Transcriptional analysis confirmed increased expression of gadB and gadR upon YE supplementation, supporting its role in activating GABA production. These findings provide valuable insights into the influence of nutrient composition on GABA production. Furthermore, they unveil the potential of L. brevis CRL 2013 as a safe, nonpathogenic strain with valuable biotechnological traits which can be further leveraged for its probiotic potential in the food industry.

Interplay between microbial-derived GABA and host GABA receptor signaling collectively influence the tumorigenic function of GABA in colon cancer.

Although classically recognized as a neurotransmitter, gamma aminobutyric acid (GABA) has also been identified in colonic tumors. Moreover, the gut microbiome represents another potential source of GABA. Both GABAA and GABAB receptors have been implicated in contributing to the effects of GABA in colorectal cancer, with both pro- and anti-tumorigenic functions identified. However, their subunit composition is often overlooked. Studies to date have not addressed whether the GABA-producing potential of the microbiome changes over the course of colon tumor development or whether receptor subunit expression patterns are altered in colon cancer. Therefore, we investigated the clusters of orthologous group frequencies of glutamate decarboxylase (GAD) in feces from two murine models of colon cancer and found that the frequency of microbial GAD was significantly decreased early in the tumorigenic process. We also determined that microbial-derived GABA inhibited proliferation of colon cancer cells invitro and that this effect of GABA on SW480 cells involved both GABAA and GABAB receptors. GABA also inhibited prostaglandin E2 (PGE2)-induced proliferation and interleukin-6 (IL-6) expression in these cells. Gene expression correlations were assessed using the "Cancer Exploration" suite of the TIMER2.0 web tool and identified that GABA receptor subunits were differentially expressed in human colon cancer. Moreover, GABAA receptor subunits were predominantly positively associated with PGE2 synthase, cyclooxygenase-2 and IL-6. Collectively, these data demonstrate decreased potential of the microbiome to produce GABA during tumorigenesis, a novel anti-tumorigenic pathway for GABA, and that GABA receptor subunit expression adds a further layer of complexity to GABAergic signaling in colon cancer.

Synthesis of versatile neuromodulatory molecules by a gut microbial glutamate decarboxylase.

Dysbiosis of the microbiome correlates with many neurological disorders, yet very little is known about the chemistry that controls the production of neuromodulatory molecules by gut microbes. Here, we found that an enzyme glutamate decarboxylase (BfGAD) of a gut microbe Bacteroides fragilis forms multiple neuromodulatory molecules such as γ-aminobutyric acid (GABA), hypotaurine, taurine, homotaurine, and β-alanine. We evolved BfGAD and doubled its taurine productivity. Additionally, we increased its specificity towards the substrate L-glutamate. Here, we provide a chemical strategy via which the BfGAD activity could be fine-tuned. In future, this strategy could be used to modulate the production of neuromodulatory molecules by gut microbes.

A bacterial effector manipulates plant metabolism, cell death, and immune responses via independent mechanisms.

Bacterial pathogens inject effector proteins inside plant cells to manipulate cellular functions and achieve a successful infection. The soil-borne pathogen Ralstonia solanacearum (Smith), the causal agent of bacterial wilt disease, secretes > 70 different effectors inside plant cells, although only a handful of them have been thoroughly characterized. One of these effectors, named RipI, is required for full R. solanacearum pathogenicity. RipI associates with plant glutamate decarboxylases (GADs) to promote the accumulation of gamma-aminobutyric acid (GABA), which serves as bacterial nutrient. In this work, we found that RipI can also suppress plant immune responses to bacterial elicitors, which seems to be unrelated to the ability of RipI to induce GABA accumulation and plant cell death. A detailed characterization of the RipI features that contribute to its virulence activities identified two residues at the C-terminal domain that mediate RipI interaction with plant GADs and the subsequent promotion of GABA accumulation. These residues are also required for the appropriate homeostasis of RipI in plant cells and the induction of cell death, although they are partially dispensable for the suppression of plant immune responses. Altogether, we decipher and uncouple the virulence activities of an important bacterial effector at the biochemical level.

Effects of dielectric barrier discharge cold plasma treatment on quality maintenance, energy and γ-aminobutyric acid accumulation of fresh-cut carrots

The effects of a novel method non-thermal cold plasma (CP) treatment on microbial control, quality maintenance, and γ-aminobutyric acid (GABA) accumulation of shred carrots were investigated. Results revealed CP treatment suppressed microbial growth and inhibited the increase in L* value and whiteness index, while stimulated the generation of reactive oxygen species. Meanwhile, it also enhanced activities and transcriptions of glutamate decarboxylase and GABA transaminase in GABA shunt, and strengthened the polyamine degradation pathway via enhancing activities of diamine oxidase (DAO), polyamine oxidase (PAO), aminoaldehyde dehydrogenase (AMADH), and the expression of DcPAO, thus in turn promoting GABA accumulation through facilitating the conversion from glutamate and polyamines into GABA. Moreover, CP treatment improved the energy status and reducing power by upregulating energy metabolism and pentose phosphate pathway. Therefore, these findings indicated that CP treatment was effective for microbial reduction, quality preservation, and GABA accumulation in fresh-cut carrots, thereby providing potential strategies for the preservation and processing of fresh-cut produce.

Enrichment of corn and alfalfa silage with γ-aminobutyric acid through inoculation with a screened high producing Lentilactobacillus buchneri strain

This study aimed to enrich corn and alfalfa silages with γ-aminobutyric acid (GABA) by utilizing high GABA-producing Lentilactobacillus buchneri. Eleven strains were screened and L. Buchneri YM9 was distinguished for its superiority in GABA production, and it was subsequently applied as an inoculant on whole-crop corn and alfalfa silage. The silage treatments were control (without inoculant), AH35 (non-GABA producing strain), YM9 (high-GABA producing strain), and 40788 (commercial GABA producing strain). The results revealed that in corn silage, pH significantly declined at the initial ensiling stage (3–7 days), with the control having the lowest pH after 90 days. The control also exhibited the highest lactic acid, while L. buchneri treatments had elevated acetic acid. Similar trends were observed in alfalfa silage, with 30 % dry matter (DM) showing lower pH and higher organic acids. YM9-inoculated corn silage had higher DM loss, reduced water-soluble carbohydrates (WSC), but increased crude protein (CP) content. YM9 and 40788 treatments in whole-crop corn silage had lower glutamate (Glu) content post-ensiling, signifying effective GABA production. YM9 treatment maintained stable and higher glutamate decarboxylase (GAD) activity, resulting in the highest GABA accumulation in corn silage (1.97 g/kg DM). Likewise, YM9 and 40788 demonstrated significantly higher GABA content in 30 % (7.6 and 6.51 g/kg DM) and 40 % (5.23 and 5.32 g/kg DM) DM alfalfa silage. Beyond enhancing fermentation and nutrient preservation, YM9 strain shows promise in enriching whole-crop corn and alfalfa with ample GABA concentration, potentially exerting anticipated biological functions when consumed by animals.

Dietary supplementation with grape seed extract from Vitus vinifera prevents suppression of GABAergic protein expression in female Sprague Dawley trigeminal ganglion in a model of chronic temporomandibular joint disorder

ObjectiveTo investigate cellular changes in protein expression in the trigeminal ganglion in an established preclinical chronic model of temporomandibular joint disorder (TMD) in response to grape seed extract (GSE) supplementation based on its beneficial use in preclinical chronic orofacial pain models. DesignThree experimental conditions included female Sprague-Dawley rats as naïve controls, and animals subjected to neck muscle inflammation and prolonged jaw opening with and without daily supplementation of GSE in the drinking water prior to inflammation. Changes were evaluated in mechanical sensitivity to von Frey filaments and protein expression in the trigeminal ganglion of animals 14 days post jaw opening. ResultsCalcitonin-gene related peptide and protein kinase A, proteins positively associated with peripheral sensitization and enhanced nociception, did not show elevated expression at day 14 in the model compared to naïve or GSE supplemented animals. However, neuronal levels of glutamate decarboxylase (GAD) 65/67, which are enzymes responsible for the synthesis of the inhibitory neurotransmitter GABA that functions to suppress neuronal excitability, were significantly decreased on day 14 post jaw opening. Similarly, a significant decrease in neuronal expression of the GABA receptor subunits GABAB1 and GABAB2, but not GABAA, was observed in the TMD model. Importantly, GSE prevented suppression of GAD 65/67 and GABAB subunits, maintaining levels similar to naïve animals. ConclusionResults from our study provide evidence of the downregulation of inhibitory GABAergic proteins in trigeminal ganglion neurons in a preclinical chronic TMD model and the benefits of GSE supplementation in preventing their suppression and maintaining normal levels.

Detection of Glutamate Decarboxylase Antibodies and Simultaneous Multi-Molecular Translocation Exploration by Glass Nanopores.

Glutamic acid decarboxylase antibody (GADAb) has emerged as a significant biomarker for clinical diagnosis and prognosis in type 1 diabetes (T1D). In this study, we investigated the potential utilization of glass capillary solid-state nanopores as a cost-effective and easily preparable platform for the detection of individual antigens, antibodies, and antigen-antibody complexes without necessitating any modifications to the nanopores. Our findings revealed notable characteristic variations in the translocation events of glutamic acid decarboxylase (GAD65) through nanopores under different voltage conditions, discovered that anomalous phenomenon of protein translocation events increasing with voltage may potentially be caused by the crowding of multiple proteins in the nanopores, and demonstrated that there are multiple components in the polyclonal antibodies (GADAb-poly). Furthermore, we achieved successful differentiation between GAD65, GADAb, and GADAb-GAD65 complexes. These results offer promising prospects for the development of a rapid and reliable GADAb detection method, which holds the potential to be applied in patient serum samples, thereby facilitating a label-free, cost-effective, and early diagnosis of type I diabetes.

Prenatal 1-Nitropyrene Exposure Causes Autism-Like Behavior Partially by Altering DNA Hydroxymethylation in Developing Brain.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, characterized by social communication disability and stereotypic behavior. This study aims to investigate the impact of prenatal exposure to 1-nitropyrene (1-NP), a key component of motor vehicle exhaust, on autism-like behaviors in a mouse model. Three-chamber test finds that prenatal 1-NP exposure causes autism-like behaviors during the weaning period. Patch clamp shows that inhibitory synaptic transmission is reduced in medial prefrontal cortex of 1-NP-exposed weaning pups. Immunofluorescence finds that prenatal 1-NP exposure reduces the number of prefrontal glutamate decarboxylase 67 (GAD67) positive interneurons in fetuses and weaning pups. Moreover, prenatal 1-NP exposure retards tangential migration of GAD67-positive interneurons and downregulates interneuron migration-related genes, such as Nrg1, Erbb4, and Sema3F, in fetal forebrain. Mechanistically, prenatal 1-NP exposure reduces hydroxymethylation of interneuron migration-related genes through inhibiting ten-eleven translocation (TET) activity in fetal forebrain. Supplement with alpha-ketoglutarate (α-KG), a cofactor of TET enzyme, reverses 1-NP-induced hypohydroxymethylation at specific sites of interneuron migration-related genes. Moreover, α-KG supplement alleviates 1-NP-induced migration retardation of interneurons in fetal forebrain. Finally, maternal α-KG supplement improves 1-NP-induced autism-like behaviors in weaning offspring. In conclusion, prenatal 1-NP exposure causes autism-like behavior partially by altering DNA hydroxymethylation of interneuron migration-related genes in developing brain.

Data-Driven Patient clusters of Type 2 Diabetes May Help to Identify Patients at Risk and Predict Metabolic Surgery Outcomes on Diabetes Remission and NAFLD Pregression

Abstract Background Precision medicine and customized medicine have gained enormous attention in recent years, especially in the treatment of type 2 diabetes (T2D). Different subgroups of diabetes have been identified by research employing data-driven cluster analysis, each with a unique diabetes progression and complication risk (Ahlqvist et al., Lancet Diabetes Endocrinol. 2018). Aims We aimed to apply the proposed cluster analysis to a patent population post metabolic surgery and investigate the association with T2D remission and presence of NAFLD. Methods We retrospectively linked newly defined clusters to metabolic surgery outcomes in 53 T2D patients. Utilizing k-means and hierarchical clustering, three clusters emerged based on glutamate decarboxylase antibodies, age, BMI, HbA1c, and homoeostatic model assessment estimates of β-cell function (HOMA2-B%) and insulin resistance (HOMA2-IR). Intraoperative liver biopsies assessed nonalcoholic fatty liver disease (NAFLD) presence differentiating between simple steatosis (NAFL) and steatohepatitis (NASH). Clinical and biochemical data were collected over two years, focusing on T2D remission and NAFLD improvement. Results Cluster 1, characterized by the lowest BMI, highest NASH rate, impaired beta-cell function, and increased insulin resistance, displayed a favorable response to surgery, indicating robust regeneration of beta-cells. Despite increased insulin production, T2D remission was surprisingly low at 44.0% after one year, in contrast to 75.00% in Cluster 2 and 100.00% in Cluster 3. Metabolic surgery notably reduced insulin resistance and promoted NASH remission, evidenced by a significant reduction in a non-invasive NASH detection score and liver enzyme levels across all three clusters. Conclusion Our findings suggest that patients in Cluster 1 already show a lack of beta-cell compensation being associated with a higher prevalence of NAFLD and poorer diabetic control and therefore especially might benefit from an earlier intervention. Data-driven classification might help to customize treatment plans and identify patients at higher risk of problems at diagnosis.

Effects of psoralidin on the expression of glutamate decarboxylases and inhibitory synapse development

Gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter required for excitation/inhibition balance is synthesized by the glutamic acid decarboxylases (GADs) in GABAergic neurons. The levels and activity of GADs are strongly correlated with GABA and neural transmission. Dysregulation of GADs and GABA is associated with various neurological disorders. The study used psoralidin, found in the seeds of Psoralea corylifolia, to investigate its effect on GAD levels and regulatory mechanisms in primary cortical neurons. Psoralidin reduced GAD67 through transcriptional regulation. The reduction was not mediated by the N-methyl-D-aspartate receptor. Additionally, psoralidin attenuated the formation of inhibitory synapses in primary hippocampal neurons.

Effects of the Combined Treatment of Trans-2-Hexenal, Ascorbic Acid, and Dimethyl Dicarbonate on the Quality in Fresh-Cut Potatoes (Solanum tuberosum L.) during Storage.

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.

The Changes of Amino-Acid Metabolism between Wheat and Rice during Early Growth under Flooding Stress.

Floods induce hypoxic stress and reduce wheat growth. On the other hand, rice is a semi-aquatic plant and usually grows even when partially submerged. To clarify the dynamic differences in the cellular mechanism between rice and wheat under flooding stress, morphological and biochemical analyses were performed. Although the growth of wheat in the early stage was significantly suppressed due to flooding stress, rice was hardly affected. Amino-acid analysis revealed significant changes in amino acids involved in the gamma-aminobutyric acid (GABA) shunt and anaerobic/aerobic metabolism. Flood stress significantly increased the contents of GABA and glutamate in wheat compared with rice, though the abundances of glutamate decarboxylase and succinyl semialdehyde dehydrogenase did not change. The abundance of alcohol dehydrogenase and pyruvate carboxylase increased in wheat and rice, respectively. The contents of aspartic acid and pyruvic acid increased in rice root but remained unchanged in wheat; however, the abundance of aspartate aminotransferase increased in wheat root. These results suggest that flooding stress significantly inhibits wheat growth through upregulating amino-acid metabolism and increasing the alcohol-fermentation system compared to rice. When plant growth is inhibited by flooding stress and the aerobic-metabolic system is activated, GABA content increases.

Choline chloride shows gender-dependent positive effects on social deficits, learning/memory impairments, neuronal loss and neuroinflammation in the lipopolysaccharide-induced rat model of autism.

The neuroprotective effects of choline chloride, an essential nutrient, a precursor for the acetylcholine and synthesis of membrane phospholipids, have been associated with neurological and neurodegenerative diseases. Its contribution to autism spectrum disorder, a neurodevelopmental disorder, remains unknown. Thus, we aimed to evaluate the effects of choline chloride on social behaviours, and histopathological and biochemical changes in a rat autism model. The autism model was induced by administration of 100 μg/kg lipopolysaccharide (LPS) on the 10th day of gestation. Choline chloride treatment (100 mg/kg/day) was commenced on PN5 and maintained until PN50. Social deficits were assessed by three-chamber sociability, open field, and passive avoidance learning tests. Tumour necrosis factor alpha (TNF-α), interleukin-2 (IL) and IL-17, nerve growth factor (NGF), and glutamate decarboxylase 67 (GAD67) levels were measured to assess neuroinflammatory responses. In addition, the number of hippocampal and cerebellar neurons and glial fibrillary acidic protein (GFAP) expression were evaluated. Social novelty and passive avoidance learning tests revealed significant differences in choline chloride-treated male rats compared with saline-treated groups. TNF-α, IL-2, and IL-17 were significantly decreased after choline chloride treatment in both males and females. NGF and GAD67 levels were unchanged in females, while there were significant differences in males. Histologically, significant changes in terms of gliosis were detected in hippocampal CA1 and CA3 regions and cerebellum in choline chloride-treated groups. The presence of ameliorative effects of choline chloride treatment on social behaviour and neuroinflammation through neuroinflammatory, neurotrophic, and neurotransmission pathways in a sex-dependent rat model of LPS-induced autism was demonstrated.

Parvalbumin Regulates GAD Expression through Calcium Ion Concentration to Affect the Balance of Glu-GABA and Improve KA-Induced Status Epilepticus in PV-Cre Transgenic Mice.

Aims: the study aimed to (i) use adeno-associated virus technology to modulate parvalbumin (PV) gene expression, both through overexpression and silencing, within the hippocampus of male mice and (ii) assess the impact of PV on the metabolic pathway of glutamate and γ-aminobutyric acid (GABA). Methods: a status epilepticus (SE) mouse model was established by injecting kainic acid into the hippocampus of transgenic mice. When the seizures of mice reached SE, the mice were killed at that time point and 30 min after the onset of SE. Hippocampal tissues were extracted and the mRNA and protein levels of PV and the 65 kDa (GAD65) and 67 kDa (GAD67) isoforms of glutamate decarboxylase were assessed using real-time quantitative polymerase chain reaction and Western blot, respectively. The concentrations of glutamate and GABA were detected with high-performance liquid chromatography (HPLC), and the intracellular calcium concentration was detected using flow cytometry. Results: we demonstrate that the expression of PV is associated with GAD65 and GAD67 and that PV regulates the levels of GAD65 and GAD67. PV was correlated with calcium concentration and GAD expression. Interestingly, PV overexpression resulted in a reduction in calcium ion concentration, upregulation of GAD65 and GAD67, elevation of GABA concentration, reduction in glutamate concentration, and an extension of seizure latency. Conversely, PV silencing induced the opposite effects. Conclusion: parvalbumin may affect the expression of GAD65 and GAD67 by regulating calcium ion concentration, thereby affecting the metabolic pathways associated with glutamate and GABA. In turn, this contributes to the regulation of seizure activity.

Using deep eutectic solvents to enhance immobilized glutamate decarboxylase for γ-aminobutyric acid synthesis

Deep eutectic solvents (DESs) can improve the catalytic efficiency of enzymes. The effect of DESs on the biocatalytic decarboxylation of sodium glutamate to γ-aminobutyric acid (GABA) by site-directed immobilized enzymes was studied. 1.5% choline chloride/glycerol (ChCl/Gly, molar ratio, 2:1) increased the catalytic rate of the site-directed immobilized enzyme by 14%. In ChCl/Gly-containing systems, the Km, kcat, activity and activation energy of the enzyme were 3.17 mM, 48.86 s−1, 48.41 U/mg and 28.69 kJ/mol, respectively. Furthermore, ChCl/Gly resulted in the change of the secondary structure of the immobilized enzyme. The optimum pH and temperature of the enzymatic reaction were 3.0 and 60 °C in ChCl/Gly-containing systems, respectively. Finally, GABA was afforded in a yield of 78.3% at a substrate concentration of up to 180 mM using a fed-batch strategy. This study provides a green and promising method for efficient GABA biosynthesis.