Γ-aminobutyric Acid Transaminase Research Articles

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.

Management of seizures in patients with primary mitochondrial diseases: consensus statement from the InterERNs Mitochondrial Working Group.

Primary mitochondrial diseases (PMDs) are common inborn errors of energy metabolism, with an estimated prevalence of one in 4300. These disorders typically affect tissues with high energy requirements, including heart, muscle and brain. Epilepsy may be the presenting feature of PMD, can be difficult to treat and often represents a poor prognostic feature. The aim of this study was to develop guidelines and consensus recommendations on safe medication use and seizure management in mitochondrial epilepsy. A panel of 24 experts in mitochondrial medicine, pharmacology and epilepsy management of adults and/or children and two patient representatives from seven countries was established. Experts were members of five different European Reference Networks, known as the Mito InterERN Working Group. A Delphi technique was used to allow the panellists to consider draft recommendations on safe medication use and seizure management in mitochondrial epilepsy, using two rounds with predetermined levels of agreement. A high level of consensus was reached regarding the safety of 14 out of all 25 drugs reviewed, resulting in endorsement of National Institute for Health and Care Excellence guidelines for seizure management, with some modifications. Exceptions including valproic acid in POLG disease, vigabatrin in patients with γ-aminobutyric acid transaminase deficiency and topiramate in patients at risk for renal tubular acidosis were highlighted. These consensus recommendations describe our intent to improve seizure control and reduce the risk of drug-related adverse events in individuals living with PMD-related epilepsy.

Sucrose, cell wall, and polyamine metabolisms involve in preserving postharvest quality of ‘Zaosu’ pear fruit by L-glutamate treatment

‘Zaosu’ pear fruit is prone to yellowing of the surface and softening of the flesh after harvest. This work was performed to assess the influences of L-glutamate treatment on the quality of ‘Zaosu’ pears and elucidate the underlying mechanisms involved. Results demonstrated that L-glutamate immersion reduced ethylene release, respiratory intensity, weight loss, brightness (L*), redness (a*), yellowness (b*), and total coloration difference (ΔE); enhanced ascorbic acid, soluble solids, and soluble sugar contents; maintained chlorophyll content and flesh firmness of pears. L-glutamate also restrained the activities of neutral invertase and acid invertase, while enhancing sucrose phosphate synthetase and sucrose synthase activities to facilitate sucrose accumulation. The transcriptions of PbSGR1, PbSGR2, PbCHL, PbPPH, PbRCCR, and PbNYC were suppressed by L-glutamate, resulting in a deceleration of chlorophyll degradation. L-glutamate concurrently suppressed the transcription levels and enzymatic activities of polygalacturonases, pectin methylesterases, cellulase, and β-glucosidase. It restrained polygalacturonic acid trans-eliminase and pectin methyl-trans-eliminase activities as well as inhibited the transcription levels of PbPL and Pbβ-gal. Moreover, the gene transcriptions and enzymatic activities of arginine decarboxylase, ornithine decarboxylase, S-adenosine methionine decarboxylase, glutamate decarboxylase, γ-aminobutyric acid transaminase, glutamine synthetase along with the PbSPDS transcription was promoted by L-glutamate. L-glutamate also resulted in the down-regulation of PbPAO, PbDAO, PbSSADH, PbGDH, and PbGOGAT transcription levels, while enhancing γ-aminobutyric acid, glutamate, and pyruvate acid contents in pears. These findings suggest that L-glutamate immersion can effectively maintain the storage quality of ‘Zaosu’ pears via modulating key enzyme activities and gene transcriptions involved in sucrose, chlorophyll, cell wall, and polyamine metabolism.

Discovery of GABA Aminotransferase Inhibitors via Molecular Docking, Molecular Dynamic Simulation, and Biological Evaluation

γ-Aminobutyric acid aminotransferase (GABA-AT) is a pyridoxal 5′-phosphate (PLP)-dependent enzyme that degrades γ-aminobutyric (GABA) in the brain. GABA is an important inhibitory neurotransmitter that plays important neurological roles in the brain. Therefore, GABA-AT is an important drug target that regulates GABA levels. Novel and potent drug development to inhibit GABA-AT is still a very challenging task. In this study, we aimed to devise novel and potent inhibitors against GABA-AT using computer-aided drug design (CADD) tools. Since the crystal structure of human GABA-AT was not yet available, we utilized a homologous structure derived from our previously published paper. To identify highly potent compounds relative to vigabatrin, an FDA-approved drug against human GABA-AT, we developed a pharmacophore analysis protocol for 530,000 Korea Chemical Bank (KCB) compounds and selected the top 50 compounds for further screening. Preliminary biological analysis was carried out for these 50 compounds and 16 compounds were further assessed. Subsequently, molecular docking, molecular dynamics (MD) simulations, and binding free energy calculations were carried out. In the results, four predicted compounds, A07, B07, D08, and H08, were found to be highly potent and were further evaluated by a biological activity assay to confirm the results of the GABA-AT activity inhibition assay.

Antiepileptics pharmacotherapy or antidiabetics may hold potential in ‎treatment of ‎‎epileptic ‎patients with diabetes mellitus: A narrative review

Several studies have reported the association of diabetes mellitus with epilepsy. With respect to ‎the management of diabetes–epilepsy patients, these studies pointed out the beneficial effects of ‎the ketogenic diet. Ketogenic diets may have antiepileptic properties as the utilization of ketone ‎bodies in the brain instead of glucose delays or inhibits the degradation of γ-aminobutyric acid ‎‎(GABA) transaminase, and thereby enhances the concentration of GABA. By restoring normal ‎intracerebral GABA levels and reducing the cerebral inflammation linked to epilepsy, metformin ‎is useful in preventing seizures. Sitagliptin is one of the dipeptidyl dipeptidase-4 inhibitors, ‎which have a positive impact on epilepsy in experimental animal models with pentylenetetrazole-‎induced seizures, by reducing reactive oxygen species, (antioxidant effect), normalization of ‎GABA level, suppression of neuroinflammation (autophagy) and reduced neuronal damage ‎‎(antiapoptotic effect). Weight gain is a well-known side effect of anti-seizure medications. ‎Sodium valproate can cause dyslipidemia and inhibit glucose transporter-1 in the brain, putting ‎patients with epilepsy and diabetes at risk of developing atherosclerosis. It's worth looking at ‎how ferroptosis and autophagy contribute to the etiology of diabetes and epilepsy, as well as ‎how antiepileptics and antidiabetics alter these pathological processes. Therefore, it was worth ‎performing a narrative-review on the effects of antiepileptics on diabetes, the effect of ‎antidiabetics on epilepsy, as well the net results of antiepileptic–antidiabetic interactions in those ‎patients.‎

Phytocompounds, antioxidant potential, and inhibitory actions of ethanolic leaf fraction of Sida linifolia Linn. (Malvaceae) on enzymes linked to inflammation, diabetes, and neurological disorders

Abstract Background Sida linifolia L. is a weed ubiquitously found in Africa with several folkloric applications. Traditional healers in the Southeastern part of Nigeria employ the alcoholic concoction of S. linifolia leaves as antidepressants, anti-malaria, antihypertensive, anti-abortifacients, and for managing painful whitlow; however, these claims lack scientific validation. The present study was aimed to explore the phytochemical profile of the plant, S. linifolia with special emphasis to its antioxidant and inhibitory actions on enzymes linked to inflammation, diabetes, and neurological disorders. Phytochemical profiling and in vitro antioxidant and enzyme inhibition assays were employed to assess the pharmacological profile of S. linifolia ethanolic leaf fraction (SLELF). Results Preliminary phytochemical screening of SLELF revealed appreciable amounts of total phenolics (91.64 ± 7.61 mg GAE/g), total tannins (62.44 ± 3.86 mg TAE/g), and total flavonoids (27.35 ± 1.48 mg QE/g) present in SLELF. Results of HPLC analysis of SLELF revealed rich composition in bioactive compounds such as ellagic acid, quercetin, ferulic acid, 3,4-dimethoxy benzoic acid, gallic acid, 4-methoxy cinnamic acid, sinapic acid, vanillic acid, and chlorogenic acid. Enzymatic antioxidants (catalase and superoxide dismutase), non-enzymatic antioxidants (reduced glutathione (GSH), Vit A, C, and E), elemental minerals (Cu, Mn, Zn, Cr, Fe, and Ca), and γ-aminobutyric acid (GABA) were present in SLELF in appreciable levels. At various concentrations (0.2–1.0 mg/ml), SLELF exhibited potent and concentration-dependent hydrogen peroxide (H2O2) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) radical scavenging activities and exerted moderate inhibitory actions on enzymes associated with inflammation (cyclooxogenase-2 (COX-2) and lipoxygenases (LOXs), diabetes (α-amylase, α-glucosidase), and neurological disorders (butyrylcholinesterase (BChE) and γ-aminobutyric acid transaminase (GABA-T), compared to respective standards (ascorbic acid, acarbose, indomethacin, galanthamine, and vigabatrin). Perhaps, the observed potent pharmacological activities of SLELF could be anchored to its phytoconstituents. Furthermore, the slightly higher ranges of IC50 values (0.57–0.87 mg/ml) of SLELF compared to standards (0.44–0.68 mg/ml) suggest moderation in enzyme inhibition that may preclude adverse side effects. Conclusion This study lends credence to the folklore claims of S. linifolia leaves and revealed its potential as possible source of bioactive compounds for medicinal and pharmaceutical exploration.

GABase and glutaminase inhibitory activities of herbal extracts and acylated flavonol monoglycosides isolated from the leaves of Laurus nobilis L.

This study was to compare GABase [a mixture of γ-aminobutyric acid (GABA) aminotransferase and succinic semialdehyde dehydrogenase] and glutaminase inhibitory activities of 20 herbal extracts and investigate the isolation, structural elucidation and those inhibitory activities of three acylated flavonol monoglycosides from the selected extract of Laurus nobilis L. (laurel). On the basis of the NMR spectroscopic data and the ESI MS spectra together with the comparison with the literature values, three compounds were identified as kaempferol-3-O-(4″-E-p-coumaroyl)-α-l-rhamnopyranoside (1), kaempferol-3-O-(3″,4″-di-E-p-coumaroyl)-α-l-rhamnopyranoside (2) and kaempferol-3-O-(2″,4″-di-E-p-coumaroyl)-α-l-rhamnopyranoside (3), respectively. The IC50 values of GABase inhibitory activity of 1-3 and p-hydroxybenzaldehyde (HBA) as control were 0.24 mM, 0.14 mM, 0.12 mM and 0.43 mM, respectively. Additionally, the IC50 values of glutaminase inhibitory activity of 1-3 and 6-diazo-5-oxo-l-norleucine (DON) as control were 0.34 mM, 0.13 mM, 0.14 mM and 0.33 mM, respectively. The results suggest that the extract from laurel shows the strongest biological activities among 20 herbal extracts and three acylated flavonol monoglycosides may serve as potential lead compounds for the prevention and treatment of neurodegenerative and lifestyle-related diseases by targeting GABase and glutaminase. This is the first report on GABase and glutaminase inhibitory activities of 1-3.

Exogenous melatonin mitigates chilling injury in zucchini fruit by enhancing antioxidant system activity, promoting endogenous proline and GABA accumulation, and preserving cell wall stability

Zucchini fruit are sensitive to chilling injury (CI) during postharvest low temperature storage which makes their cold stored life short. In this work, zucchini fruit were treated with melatonin (200 µmol L−1) and stored at 5 ºC for 15 d. The pre-storage melatonin treatment reduced weight loss (6.51%) and suppressed symptoms of CI (1.5 Score) along with lower malondialdehyde (MDA), relative ion leakage (RIL), superoxide anion and hydrogen peroxide (H2O2) in contrast with control. The treated zucchini exhibited higher L* (51.89) and lower a* (−10.17) and b* (29.15) values of exocarp in comparison with control. Melatonin treated zucchini showed enhanced γ-aminobutyric acid (GABA) concentration due to higher glutamate content and stimulated glutamate decarboxylase (GAD) and suppressed γ-aminobutyric acid transaminase (GABA-T) activities. In addition, melatonin application increased proline accumulation owing to stimulation of Δ-1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine δ-aminotransferase (OAT) enzymes and reduced proline dehydrogenase (ProDH) activity as compared with control. The activity of antioxidative such as ascorbate peroxidase (APX), peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) enzymes remained higher in melatonin treated zucchini. The fruit treated with melatonin exhibited reduced water soluble pectin (WSPN) along with higher sodium carbonate soluble pectin (SCSP), protopectin (PRPN), chelate soluble pectin (CSPN), cellulose (CLS) and hemicellulose (HLS) in comparison with control. The exogenous melatonin suppressed the activities of polygalacturonase (PG), β-galactosidase (β-Gal), cellulase (CX), and pectin methylesterase (PME) along with higher firmness. In conclusion, exogenous melatonin at 200 µmol L−1 concentration could be used for zucchini fruit CI mitigation under cold storage.

The conditional mitochondrial protein complexome in the Arabidopsis thaliana root and shoot

Protein complexes are important for almost all biological processes. Hence, to fully understand how cells work, it is also necessary to characterize protein complexes and their dynamics in response to various cellular cues. Moreover, the dynamics of protein interaction play crucial roles in regulating the (dis)association of protein complexes and, in turn, regulating biological processes such as metabolism. Here, mitochondrial protein complexes were investigated by blue native PAGE and size-exclusion chromatography under conditions of oxidative stress in order to monitor their dynamic (dis)associations. Rearrangements of enzyme interactions and changes in protein complex abundance were observed in response to oxidative stress induced by menadione treatment. These included changes in enzymatic protein complexes involving γ-amino butyric acid transaminase (GABA-T), Δ-ornithine aminotransferase (Δ-OAT), or proline dehydrogenase 1 (POX1) that are expected to affect proline metabolism. Menadione treatment also affected interactions between several enzymes of the tricarboxylic acid (TCA) cycle and the abundance of complexes of the oxidative phosphorylation pathway. In addition, we compared the mitochondrial complexes of roots and shoots. Considerable differences between the two tissues were observed in the mitochondrial import/export apparatus, the formation of super-complexes in the oxidative phosphorylation pathway, and specific interactions between enzymes of the TCA cycle that we postulate may be related to the metabolic/energetic requirements of roots and shoots.

N-α-Lauroyl-L-arginine ethyl ester hydrochloride combined with hot water treatment alleviates chilling injury of postharvest cucumber fruit

Postharvest cucumber fruit is prone to chilling injury (CI) under cold stress, leading to severe quality deterioration. In this study, the effects of N-α-Lauroyl-l-arginine ethyl ester hydrochloride (LAE), hot water (HW), and LAE combined with HW treatments on CI in cucumber fruit stored at 4 ± 1 ℃ were investigated. The response surface methodology (RSM) confirmed that the LAE concentration of 1.00 g L−1, HW temperature of 44 ℃, and immersion time of 10 min were the optimal condition for cucumber fruit preservation during cold storage. Further analysis revealed that LAE, HW, and LAE combined with HW treatments, all significantly mitigated chilling injury symptoms in cucumber fruit in comparison with the control, but the application of LAE combined with HW was the most effective method for enhancing cold tolerance in cucumber fruit. Moreover, LAE combined with HW treatment could reduce reactive oxygen species (ROS) accumulation, and enhance superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) activities in cold-stored cucumber fruit. Meanwhile, the activities of arginine decarboxylase (ADC), ornithine decarboxylase (ODC), Δ1-pyrroline-5-carboxylate synthetase (P5CS), ornithine δ-aminotransferase (OAT), and glutamate decarboxylase (GAD) were also increased by LAE combined with HW treatment, while the activities of proline dehydrogenase (PDH) and γ-aminobutyric acid transaminase (GABA-T) were decreased by LAE combined with HW treatment, which contributed to maintaining higher polyamines, proline, and GABA contents. These findings suggested that LAE combined with HW treatment can reduce chilling injury in cucumber fruit via enhancing antioxidant enzymes activities, PA, proline, and GABA contents to maintain ROS homeostasis during cold storage.

Kinetic Characterization and Catalytic Mechanism of N-Acetylornithine Aminotransferase Encoded by slr1022 Gene from Synechocystis sp. PCC6803.

The enzyme encoded by slr1022 gene from Synechocystis sp. PCC6803 was reported to function as N-acetylornithine aminotransferase, γ-aminobutyric acid aminotransferase, and ornithine aminotransferase, which played important roles in multiple metabolic pathways. Among these functions, N-acetylornithine aminotransferase catalyzes the reversible conversion of N-acetylornithine to N-acetylglutamate-5-semialdehyde with PLP as cofactor, which is a key step in the arginine biosynthesis pathway. However, the investigation of the detailed kinetic characteristics and catalytic mechanism of Slr1022 has not been carried out yet. In this study, the exploration of kinetics of recombinant Slr1022 illustrated that Slr1022 mainly functioned as N-acetylornithine aminotransferase with low substrate specificity to γ-aminobutyric acid and ornithine. Kinetic assay of Slr1022 variants and the model structure of Slr1022 with N-acetylornithine-PLP complex revealed that Lys280 and Asp251 residues were the key amino acids of Slr1022. The respective mutation of the above two residues to Ala resulted in the activity depletion of Slr1022. Meanwhile, Glu223 residue was involved in substrate binding and it served as a switch between the two half reactions. Other residues such as Thr308, Gln254, Tyr39, Arg163, and Arg402 implicated a substrate recognition and catalytic process of the reaction. The results of this study further enriched the understanding of the catalytic kinetics and mechanism of N-acetylornithine aminotransferase, especially from cyanobacteria.

Identification of novel C-15 fluoro isosteviol derivatives for GABA-AT inhibition by in silico investigations

The treatment of epilepsy is associated with the inhibition of γ-aminobutyric acid-aminotransferase (GABA-AT), which suppresses the concentration of a key neurotransmitter GABA. Isosteviol, a natural bioactive molecule, has been reported to possess an anticonvulsant property. In this work, we first reported a series of C-15 fluoro isosteviol analogs which are bearing different functional groups at C-16 to investigate the interactions with GABA-AT by applying molecular docking and molecular dynamic simulation approach. The results revealed that all fluoro isosteviol analogs displayed a greater binding affinity than references vigabatrin, an FDA-approved GABA-AT inactivator, and CPP-115, which has Orphan Drug Designation status, and positioned at the same binding site as references. Furthermore, molecular dynamic (MD) simulation studies on minimum (A1), maximum (E1) binding energy score of fluoro isosteviol analogs, and isosteviol (G1) revealed their stable complex formation in terms of RMSD, RMSF, RG, and hydrogen bond formation. All analogs were found to have drug-like nature, non-toxic, >80% absorption, and the majority tend to penetrate brain-blood-barrier (BBB). The investigations found in this study can help in the development of isosteviol derivatives as drugs for the treatment of epilepsy. The two-dimensional (2D) ligand structures were drawn using ChembioDraw Ultra 14.0. Molecular docking with Autodock4 and molecular dynamic simulation with GROMACS version 2020.1 were performed. The CHARMM27 all-atom force field was applied for writing the topology. Biovia Discovery Studio DS2021 was used for viewing and analyzing the protein-ligand complexes. The data generated from molecular dynamic simulation trajectories were plotted using the Origin® 8 software. The Open Babel software was utilized for extracting SMILEs files of all the fluoro isosteviol analogs. The drug-likeness and ADMET of the molecules were evaluated by SwissADME and ADMETlab 2.0 web tools.

Regulatory Effect of Exogenous γ-Aminobutyric Acid on Respiratory Rate through the γ-Aminobutyric Acid Shunt in Malus baccata (L.) Borkh. Roots under Suboptimal Low Root-Zone Temperature

Malus baccata (L.) Borkh. is one of the most widely used rootstocks in the apple-producing region of Northern China. However, in the early growing season, apple roots are often subjected to suboptimal low root-zone temperatures. The regulatory effects of exogenous γ-aminobutyric acid (GABA) on both the γ-aminobutyric acid shunt (GABA shunt) and the respiratory activity of roots under suboptimal low root-zone temperatures remain unknown. To explore the physiological basis for GABA alleviation of low-temperature stress in M. baccata Borkh. roots, the following treatments were examined: suboptimal low root-zone temperature (potted parts of the seedlings were maintained at 5 ± 0.5 °C; L); suboptimal low root-zone temperature + GABA (LG); and suboptimal low root-zone temperature + vigabatrin (VGB; LV), which is a specific active inhibitor of γ-aminobutyric acid transaminase (GABA-T). Each treatment was matched with a control (18 °C/8 °C day/night; CK) for comparison. Our results showed that the L treatment reduced the root vitality, increased malondialdehyde (MDA) content, promoted the accumulation of GABA, activated the GABA shunt, and inhibited the total root respiration rate (VTotal) by decreasing the respiratory rates of Embden–Meyerhof pathway (VEMP) and tricarboxylic acid cycle (VTCAC). The LG treatment significantly increased the content of endogenous GABA, accelerated the metabolism of the GABA shunt, enhanced root respiratory activity by increasing VTotal, VEMP, VTCAC, and increased the cytochrome pathway respiratory rate (VCP), thus alleviating the damage of low root-zone temperature stress. Meanwhile, contrasting results were observed in the LV treatment. These findings revealed that exogenous GABA improved the tolerance of apple rootstocks to suboptimal low temperatures in early spring by regulating the GABA shunt and root respiratory activity.

Structural and Mechanistic Basis for the Inactivation of Human Ornithine Aminotransferase by (3S,4S)-3-Amino-4-fluorocyclopentenecarboxylic Acid.

Ornithine aminotransferase (OAT) is overexpressed in hepatocellular carcinoma (HCC), and we previously showed that inactivation of OAT inhibits the growth of HCC. Recently, we found that (3S,4S)-3-amino-4-fluorocyclopentenecarboxylic acid (5) was a potent inactivator of γ-aminobutyric acid aminotransferase (GABA-AT), proceeding by an enamine mechanism. Here we describe our investigations into the activity and mechanism of 5 as an inactivator of human OAT. We have found that 5 exhibits 10-fold less inactivation efficiency (kinact/KI) against hOAT than GABA-AT. A comprehensive mechanistic study was carried out to understand its inactivation mechanism with hOAT. pKa and electrostatic potential calculations were performed to further support the notion that the α,β-unsaturated alkene of 5 is critical for enhancing acidity and nucleophilicity of the corresponding intermediates and ultimately responsible for the improved inactivation efficiency of 5 over the corresponding saturated analogue (4). Intact protein mass spectrometry and the crystal structure complex with hOAT provide evidence to conclude that 5 mainly inactivates hOAT through noncovalent interactions, and that, unlike with GABA-AT, covalent binding with hOAT is a minor component of the total inhibition which is unique relative to other monofluoro-substituted derivatives. Furthermore, based on the results of transient-state measurements and free energy calculations, it is suggested that the α,β-unsaturated carboxylate group of PLP-bound 5 may be directly involved in the inactivation cascade by forming an enolate intermediate. Overall, compound 5 exhibits unusual structural conversions which are catalyzed by specific residues within hOAT, ultimately leading to an enamine mechanism-based inactivation of hOAT through noncovalent interactions and covalent modification.

Effect of Light Irradiation on Sugar, Phenolics, and GABA Metabolism on Postharvest Grape (Vitis vinifera L.) During Storage

The impact of red and blue light-emitting diodes (LEDs) irradiation on the sugar metabolism and γ-aminobutyric acid in postharvest table grapes stored at 4 °C for 21 days after harvest were explored. Grape clusters were exposed to red and blue light irradiation at the same intensity (500 lx). The findings revealed that red and blue light treatments enhanced total soluble solids (TSS) and total acidity (TA) content. Furthermore, red-light irradiation retained higher phenolic compound during storage than blue light and control. Red-light radiation sustained higher levels of phenolic biosynthesis-related enzymes, including phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), cinnamate 4-hydroxylase (C4H), and p-coumarate ligase (4CL), than blue light irradiation and control. The results showed that red light increased glucose, fructose, and sucrose levels, which were 32.19, 33.18, and 2.95 mg g−1, compared with those in blue light and control at the end of storage and enhancing the sucrose synthase synthesis (SS-synthesis) and acid invertase (AI), while blue light enhanced sucrose synthase cleavage (SS-cleavage). In addition, red light irradiation increased glutamic acid decarboxylase (GAD) activity while red and blue light irradiation inhibited γ-aminobutyric acid transaminase (GABA-T) activity by 22.14 and 20.71 U g−1 at 21 days of storage, compared to control, leading to γ-aminobutyric acid (GABA) accumulation. These findings suggest that red and blue light will help in maintaining the quality of grape during postharvest storage.

Effect of electroacupuncture of Governor Vessel on expression of GAD67 and GABA-T in cerebral cortex of rats with post-stroke limb spasticity

To observe the effect of electroacupuncture (EA) of Governor Vessel (GV) on the expressions of glutamate decarboxylase 67 (GAD67) and γ-aminobutyric acid transaminase (GABA-T) in the cerebral cortex of rats with post-stroke limb spasticity, so as to explore its mechanism underlying improvement of limb spasticity. Twenty four male SD rats were randomly and equally divided into control, sham operation, model, and EA groups. The cerebral ischemia model was established by occlusion of the middle cerebral artery (MCAO). EA (100 Hz, 1-3 mA) was applied to "Dazhui"(GV14), "Jizhong"(GV6) and "Houhui"( anteromedial of transverse process of the sixth lumbar vertebra) for 30 min, once daily for 7 consecutive days. The neurologic deficit score (0-5 points) was evaluated according to Zea Longa's method, and the muscular tension severity (0-5 points) was assessed according to the modified Ashworth muscle tone rating scale, and the tension signals of the quadriceps ferroris of the affected limb were recorded using tonotransducer and BL-420F electrophysiological recorder. The expression levels of GAD67 and GABA-T proteins and mRNAs in the cerebral cortex were detected by immunohistochemistry, fluorescence quantitative real-time PCR and Western blot, separately. After modeling, the neurological deficit score, muscle tone score, and the expression levels of GABA-T mRNA and protein in cerebral cortex were significantly increased (P<0.01, P<0.05), tension signal value and the expression levels of GAD67 mRNA and protein in cerebral cortex were significantly decreased (P<0.01) in the model group relevant to the control and sham operation groups. Following the intervention, the neurological deficit score, muscle tone score, and expression levels of GABA-T mRNA and protein in cerebral cortex were significantly decreased (P<0.01), tension signal value and the expression levels of GAD67 mRNA and protein in cerebral cortex were significantly increased (P<0.01, P<0.05) in the EA group in contrast to the model group. EA stimulation of Governor Vessel can ameliorate the limb spasticity symptom in MCAO rats, which may be associated with its functions in increasing the expressions of GAD67 protein and mRNA and inhibiting the expressions of GABA-T protein and mRNA, thereby playing the inhibitory role of GABA.

Metabolic, genetic, and pharmacokinetic parameters for the prediction of olanzapine efficacy

Clinical use of the a olanzapine has significantly different individual-to-individual outcomes. Accordingly, this study aimed to develop a means of predicting response to olanzapine using a combined approach based on pharmacokinetics, pharmacometabonomics, and genetic polymorphism. The olanzapine pharmacokinetics of 19 healthy volunteers treated with orally disintegrating tablets were determined using high-performance liquid chromatography–tandem mass spectrometry. Metabolic profiling and phenotyping were performed on the blood samples that remained after pharmacokinetic analysis using ultrahigh-performance liquid chromatography coupled with high-resolution mass spectrometry. Uridine diphosphate-glucuronosyltransferase (UGT), tyrosine hydroxylase (TH), γ-aminobutyric acid transaminase (GABA-T), and succinic semialdehyde dehydrogenase (SSADH) were identified as key genes. The single nucleotide polymorphism genotypes most related to drug metabolism were investigated by polymerase chain reaction and Sanger sequencing. Forty-one metabolites (p < 0.05) are increased or decreased after treatment with olanzapine. Tryptophan metabolism, norepinephrine metabolism, and γ-aminobutyric acid metabolism were identified as being related to the effects of olanzapine. Subjects carrying rs1641031 AC and CC exhibited a 59.2% increase in the mean peak concentration (Cmax) value and a 25.33% decrease in the mean oral clearance rate (CL/F) value, compared to that in subjects with the GABA-T rs1641031 AA genotype (p < 0.05). Moreover, polymorphism of the GABA-T gene has an impact on the metabolism of 5-hydroxytryptamine. Lysophosphatidylethanolamine (0:0/18:3), lysophosphatidylethanolamine (0:0/22:5), and octadecatrienoic acid distinguish subjects with high and low olanzapine drug oral clearance and are thus identified as biomarkers for predicting its efficacy.

Synthesis, characterization, and biological evaluation of some novel ϒ-aminobutyric acid aminotransferase (GABA-AT) inhibitors

In our present work, some novel substituted 4-phenyl-5-vinylpyrrolidin-2-one derivatives were designed, synthesized, and evaluated for their γ-aminobutyric acid-aminotransferase (GABA-AT) inhibition and in-vivo anticonvulsant activity. Among all the synthesized derivatives, compound 7f was observed as the most potent and competitive inhibitor of GABA-AT (IC50 = 46.29 ± 3.19 µM, Ki = 0.106 ± 0.004 μM). The in-vivo anticonvulsant activity against maximum electroshock (MES) and PTZ, induced seizures test of compound 7f, was observed very significantly (P < 0.05) in comparison with standard Vigabatrin and have shown an increase in the level of GABA in the cortex region of the brain. The ex-vivo studies have also suggested reduced tissue necrosis. Finally, In-silico molecular docking and dynamics studies of compound 7f have shown that it forms desired amino acid residue interactions with the GABA-AT and was stable for 50 ns in the active site pocket of the enzyme.

Temporal kinetics of changes in color, phytochemicals, γ-aminobutyric acid, enzyme activity and antioxidant activity of coffee leaves during postharvest storage

Understanding the kinetics of changes in the quality attributes and enzyme activity of coffee leaves during storage is essential to preparing high-quality coffee leaf tea. In the present study, the impacts of different storage temperatures and times on the color, phytochemical composition, amino acids, the activity of enzymes (glutamate decarboxylase (GAD), diamine oxidase (DAO), polyamine oxidase (PAO), γ-aminobutyraldehyde dehydrogenase (AMADH), γ-aminobutyric acid transaminase (GABA-T), glutamate dehydrogenase (GDH), polyphenol oxidase (PPO), and peroxidase (POD)), and antioxidant activity of coffee leaves were investigated. The results showed that low-temperature storage effectively delayed the production of browning color and retained nutrients and antioxidant activity in coffee leaves during storage. The content of 5-caffeoylquinic acid (5-CQA) decreased by 43.5%, 31.1%, and 17.5% when coffee leaves stored for 7 d at 25, 4, and -20 ℃, respectively. The total phenolic content (TPC) and antioxidant activity had negative correlation with the storage time and the activities of PPO and POD were enhanced with prolonged storage time and higher storage temperature. The content of γ-aminobutyric acid (GABA) increased (2.45–3.32 folds) when stored at -20 ℃ within 21 d, which was associated with the decrease of glutamic acid content and the increased activity of GAD. The kinetics of changes in color index L*, total color change (ΔE), TPC, and ABTS and DPPH scavenging capacities fitted the first-order kinetic model and the activation energies ranged from 15.66 to 24.67 kJ/mol, indicating that coffee leaves are prone to deterioration during storage, especially at high temperature. This study indicates that low-temperature storage can effectively prevent the quality loss of coffee leaves while increasing the bioactive compound GABA.

Whole Transcriptome Sequencing Reveals Drought Resistance-Related Genes in Upland Cotton.

China, particularly the cotton-growing province of Xinjiang, is experiencing acute agricultural water shortages, stifling the expansion of the cotton sector. Discovering drought resistance genes in cotton and generating high-quality, drought-resistant cotton varieties through molecular breeding procedures are therefore critical to the cotton industry’s success. The drought-resistant cotton variety Xinluzhong No. 82 and the drought-sensitive cotton variety Kexin No. 1 were utilised in this study to uncover a batch of drought-resistant candidate genes using whole transcriptome sequencing. The following are the key research findings: A competing endogenous RNA network (ceRNA) was built using complete transcriptional sequencing to screen the core genes in the core pathway, and two drought-related candidate genes were discovered. It was found that γ-aminobutyric acid aminotransferase (GhGABA-T, Gohir.A11G156000) was upregulated at 0 h vs. 12 h and downregulated at 12 h vs. 24 h. L-Aspartate oxidase (GhAO, Gohir.A07G220600) was downregulated at 0 h vs. 12 h and upregulated at 12 h vs. 24 h. GABA-T is analogous to a pyridoxal phosphate-dependent transferase superfamily protein (POP2) in Arabidopsis thaliana and influences plant drought resistance by controlling γ-aminobutyric acid (GABA) concentration. The analogue of GhAO in A. thaliana is involved in the early steps of nicotinamide adenine dinucleotide (NAD) production as well as in plant antioxidant responses. This study revealed that gene expression regulatory networks can be used for rapid screening of reliable drought resistance genes and then utilised to validate gene function.