Gamma-aminobutyric Acid Concentrations Research Articles

Sleep-enhancing activity of fermented pea protein hydrolysate with enhanced GABA content by Lactobacillus brevis SYLB 0016 fermentation.

Sleep is essential for overall health and wellbeing. This study investigated the sleep-promoting effects of fermented pea protein hydrolysate (PPF) with increased gamma-aminobutyric acid (GABA) content produced by Lactobacillus brevis SYLB 0016. The effects of PPF on sleep duration and structure were assessed in pentobarbital-induced ICR mice and Sprague Dawley (SD) rats using electroencephalogram (EEG) analysis. Hydrolysis of pea protein with Alcalase, Protana Prime, and Protana UBoost increased the amino nitrogen content, degree of hydrolysis and glutamate content to 160.51 mmol L-1. Fermentation by Lactobacillus brevis SYLB 0016 increased the GABA content from 3.16 to 90.35 mmol L-1. PPF significantly increased sleep duration (56.3 min) compared to the normal control (30.6 min) in pentobarbital-induced sleep tests. Non-rapid eye movement (NREM) sleep time increased with a significant rise in δ-waves activity following administration of 150 mg kg-1 of PPF. In caffeine-induced insomnia, both low- and high-dose PPF significantly increased sleep duration. Three weeks of oral PPF administration elevated GABAA and GABAB receptor expression, with GABAA receptor protein levels showing a significant change. Co-administration of flumazenil with PPF reduced sleep time, indicating the involvement of the GABAA receptor benzodiazepine site in PPF's sleep-enhancing effects. In conclusion, PPF with enhanced GABA content improves NREM sleep by increasing δ waves activity. As a hypoallergenic compound, PPF holds potential as a supplement to ameliorate sleep disorders. © 2025 Society of Chemical Industry.

Optimization of progesterone treatment via response surface methodology to maintain quality and mitigate chilling injury in Prunus persica L.

ABSTRACT Peach fruit is susceptible to deterioration, such as browning, highlighting the importance of applying effective preservation treatments to maintain quality. This study investigated the effect of progesterone (PRG) on the storability of mature peach fruit (cv. ‘Early Swelling’). In the initial experiment, response surface methodology (RSM) was applied to evaluate key quality indicators, including browning, firmness, proline, and gamma-aminobutyric acid (GABA) content to determine the optimal PRG concentration (1–30 µM) and treatment duration (1–30 min). Based on the RSM findings, a second experiment was applied using either 10 or 15 µM PRG for 10 min, selected as optimal conditions, compared with untreated controls. The peach fruits were stored at 2 °C with 90–95% RH for 32 days. The findings demonstrated that all PRG treatments efficiently preserved fruit quality and prolonged storability relative to the control. PRG treatment at 15 µM showed superior efficacy, significantly reducing browning, malondialdehyde, and weight loss while sustaining total phenolics, firmness, and DPPH radical scavenging activity. Moreover, PRG treatments enhanced pectin methylesterase activity, proline levels, and GABA content. These outcomes suggest that PRG application is a promising approach for improving peach fruit storability, minimising postharvest deterioration, and maintaining quality during extended storage.

γ-Aminobutyric Acid (GABA) Metabolic Bypass Plays a Crucial Role in Stress Tolerance and Biofilm Formation in C. sakazakii ATCC 29544.

Cronobacter sakazakii is a foodborne pathogen characterized by its robust stress tolerance and ability to form biofilms, which facilitates its survival in powdered infant formula (PIF) processing environments for prolonged periods. Gamma-aminobutyric acid (GABA) is a kind of non-protein amino acid that acts as an osmoprotectant. This study aimed to elucidate the effects of the gabT gene on the survival of C. sakazakii, GABA accumulation, and biofilm formation under desiccation, osmotic stress, and acid exposure. A gabT knockout strain of C. sakazakii was developed using gene recombination techniques. The GABA content and survival rates of both the wild-type and knockout strains were compared under various stress conditions. Scanning electron microscopy (SEM) was used to observe cellular damage and biofilm formation. Statistical analysis was performed using a one-way analysis of variance (ANOVA). The deletion of gabT resulted in enhanced GABA accumulation under different stress conditions, improving the bacterium's tolerance to desiccation, osmotic pressure, and acid treatment. SEM images revealed that under identical stress conditions, the gabT knockout strain exhibited less cellular damage compared to the wild-type strain. Both strains were capable of biofilm formation under low osmotic pressure stress, but the gabT knockout strain showed higher GABA content, denser biofilm formation, and increased biofilm quantity. Similar trends were observed under acid stress conditions. The gabT gene plays a key role in modulating GABA accumulation, which enhances the stress tolerance and biofilm formation of C. sakazakii. These findings provide new insights into the role of GABA in bacterial survival mechanisms and highlight the potential for targeting GABA pathways to control C. sakazakii in food processing environments.

The effect of 3-di-o-tolylguanidine on the level of neurotransmitters in the cerebellum and related disorders of social behavior.

It is common knowledge that the cerebellum is a structure of the central nervous system that influences the processes of balance and motor coordination. Recently its influence on social interactions has also been emphasized. The sigma receptor agonist: 3-di-o-tolylguanidine (DTG) is characterized by high affinity for sigma 1 and sigma 2 receptors, widely distributed in the cerebellum. In the experiment we assessed the effect of long term administration of DTG to adult male Sprague Dawley rats on social behavior and the concentration of neurotransmitters in the cerebellum. DTG was administered orally at a dose of 3mg/kg body weight (bw) (DTG3), 10mg/kg bw (DTG10) and 30mg/kg bw (DTG30) for 9weeks before the behavioral test. After the experiment, the concentration of catecholamines and amino acids in the cerebellum was assessed using high performance liquid chromatography (HPLC). Treatment groups showed reductions in social interactions such as grooming, sniffing and total time spent interacting. At the same time, it was shown that in the group receiving the lowest dose of the drug, a decrease in the concentration of dopamine and serotonin in the cerebellum was observed. Furthermore, changes in the concentration of taurine, alanine, glutamic acid and gamma-aminobutyric acid were observed in the treated groups. We found that long term administration of DTG disturbs animals' social interactions and the concentration of neurotransmitters in the cerebellum.

Effects of Pretreatment Methods on Gamma-Aminobutyric Acid Enrichment and Quality Improvement in Highland Barley Beverages.

Gamma-aminobutyric acid (GABA) is an important neurotransmitter that promotes sleep and reduces anxiety, but its natural synthesis in the body is insufficient, necessitating dietary intake. This study utilized a combination of germination, the addition of active barley powder, and fermentation to enhance GABA content in an enzymatically hydrolyzed highland barley beverage. The samples were divided into five groups: highland barley (HB), germinated highland barley (GB), highland barley supplemented with another high-glutamic-acid decarboxylase-active highland barley powder TB13 (BT), germinated barley supplemented with TB13 (GBT), and germinated barley supplemented with TB13 followed by fermentation (GBTF). The results indicated that all the pretreatments significantly elevated GABA levels, with the GBT sample showing the highest GABA content, which was 2.4 times that of the HB sample. Germination had minimal impact on the taste and aroma of the beverage, while the addition of TB13 active barley powder caused only slight changes to the aroma. The GABA content in the GBTF sample was 2.2 times higher than in the HB sample, and the GBTF sample also exhibited the highest total phenolic content, demonstrating the strongest antioxidant and free-radical scavenging abilities. Furthermore, the GBTF treatment increased acidity, reduced bitterness, and significantly altered the flavor profile of the barley beverage, enhancing its overall quality and consumer appeal as a GABA-rich functional drink.

Asymmetric dynamics of GABAergic system and paradoxical responses of GABAergicneurons in piriform seizures.

The piriform cortex (PC) plays a critical role in ictogenesis, where an excitation/inhibition imbalance contributes to epilepsy etiology. However, the epileptic dynamics of the gamma-aminobutyric acid (GABA) system and the precise role of GABAergic neurons within the PC in epilepsy remain unclear. We combined Ca2+ and GABA sensors to investigate the dynamics of Gad2-expressing neurons and GABA levels, and selectively manipulated GABAergic neurons in the PC through chemogenetic inhibition and caspase3-mediated apoptosis targeting Gad2 interneurons. GABAergic system dynamics in the PC were bidirectional and asymmetric,accompanied by PC optokindling-induced seizures, notably characterized by a robust response of Gad2 neurons but a rapid descent of GABA content during seizures. Chemogenetic inhibition of PC Gad2 neurons induced seizure-like behavior, with a discrepancy between the GABAergic neuron activities and GABA levels, signifying a transition from interictal to ictal states. Surprisingly, selective inhibition of Gad2 neurons in the PC produced paradoxical activation in a subset of Gad2 neurons. Moreover, the chronic deficiency of PC Gad2 neurons triggered spontaneous recurrent seizures. Our findings uncover the dynamic interplay within PC inhibitory components and elaborate counteractive mechanisms in seizure regulation. These insights could inform future therapeutic strategies targeting GABAergic neurons to control epileptic activity.

Reduced content of gamma-aminobutyric acid enhances resistance to bacterial wilt disease in tomato.

Bacteria within the Ralstonia solanacearum species complex cause devastating diseases in numerous crops, causing important losses in food production and industrial supply. Despite extensive efforts to enhance plant tolerance to disease caused by Ralstonia, efficient and sustainable approaches are still missing. Before, we found that Ralstonia promotes the production of gamma-aminobutyric acid (GABA) in plant cells; GABA can be used as a nutrient by Ralstonia to sustain the massive bacterial replication during plant colonization. In this work, we used CRISPR-Cas9-mediated genome editing to mutate SlGAD2, which encodes the major glutamate decarboxylase responsible for GABA production in tomato, a major crop affected by Ralstonia. The resulting Slgad2 mutant plants show reduced GABA content, and enhanced tolerance to bacterial wilt disease upon Ralstonia inoculation. Slgad2 mutant plants did not show altered susceptibility to other tested biotic and abiotic stresses, including drought and heat. Interestingly, Slgad2 mutant plants showed altered microbiome composition in roots and soil. We reveal a strategy to enhance plant resistance to Ralstonia by the manipulation of plant metabolism leading to an impairment of bacterial fitness. This approach could be particularly efficient in combination with other strategies based on the manipulation of the plant immune system, paving the way to a sustainable solution to Ralstonia in agricultural systems.

Cerebellar contribution to emotion regulation and its association with medial frontal GABA level.

Distancing involves changing perspectives to alter the psychological distance from stimuli that elicit emotional reactions as a tactic to regulate emotions. Using magnetic resonance spectroscopy (MRS) and functional magnetic resonance imaging, this study aimed to examine 1) whether the neural correlates of emotion upregulation via distancing differ across emotional valence (i.e., emotional responses toward positive and negative pictures), and 2) whether the gamma-aminobutyric acid (GABA) concentration in the medial prefrontal cortex (MPFC), one of the crucial areas of emotion regulation, is correlated with brain activity related to either negative or positive emotion upregulation. Thirty-four healthy Japanese adults participated in this study. Compared to the condition involving positive emotion upregulation, negative emotion upregulation induced increased activation in the MPFC, left temporoparietal junction, bilateral anterior insula, pre-supplementary motor area, and bilateral cerebellum. In contrast, when comparing positive emotion upregulation with negative emotion upregulation, no significant activation was found. Right cerebellar activity during negative emotion upregulation positively correlated with GABA concentration in the MPFC. These findings provide evidence of cerebellar involvement in the upregulation of negative emotion via distancing and its association with the prefrontal GABA concentration.

High-dose Vitamin-B6 reduces sensory over-responsivity.

Sensory reactivity differences are experienced by between 5% and 15% of the population, often taking the form of sensory over-responsivity (SOR), in which sensory stimuli are experienced as unusually intense and everyday function is affected. A potential mechanism underlying over-responsivity is an imbalance between neural excitation and inhibition in which inhibitory influences are relatively weakened. Therefore, interventions that boost neural inhibition or reduce neural excitation may reduce SOR; Vitamin-B6 is the coenzyme for the conversion of excitatory glutamate to inhibitory gamma-aminobutyric acid (GABA), and in animal models, it both increases the concentration of GABA and reduces glutamate. To discover whether taking a high dose of Vitamin-B6 reduces SOR and other aspects of sensory reactivity. We recruited 300 adults (249 females) from the general population who completed the Sensory Processing 3-Dimensions Scale (SP-3D) first at baseline, and again following randomisation to either 1 month's supplementation with 100 mg Vitamin-B6, or one of two control conditions (1000 µg Vitamin-B12 or placebo). To focus on individuals who experience SOR, we analysed the effects of supplementation only on individuals with high baseline SOR scores (above the 87th percentile). In individuals with SOR at baseline, Vitamin-B6 selectively reduced SOR compared to both placebo and Vitamin-B12. We also found that Vitamin-B6 selectively reduced postural disorder in individuals with high scores on this subscale at baseline, but there were no effects on the four remaining SP-3D subscales. Clinical trials and mechanistic studies should now be conducted in autism, attention deficit hyperactivity disorder and other groups with SOR.

Melatonin alleviates drought stress and increases lutein and zeaxanthin industrial pigments in African marigold by some physiological regulations

African marigold (Tagetes erecta L.), a member of the Asteraceae family, contains valuable bioactive compounds like carotenoids (Lutein and zeaxanthin), utilized in supplements, food coloring, and poultry feed additives. In light of utilizing dry, low-yield lands, this study focused on enhancing African marigolds' quantitative and qualitative characteristics through melatonin foliar treatments (0, 100, and 200 µmol) under varying stress levels (100 %, 80 %, 60 %, and 40 % FC) that were implemented as a factorial experiment using a completely randomized design with 4 replications. Results indicated deteriorating effects on African marigold flowers under increasing drought stress, mitigated by melatonin treatments that improved flower quality, reduced stress index, and enhanced agro-morphological traits. Melatonin treatments increased lutein and zeaxanthin content while maintaining chlorophyll, carotenoids, and plant growth under drought stress. Moreover, they reduced hydrogen peroxide, superoxide, electrolyte leakage, maintained protein content, DPPH activity, and enhanced antioxidant and osmolality capacity such as antioxidant enzymes activity (catalase, peroxidase, superoxide dismutase) proline and gamma-aminobutyric acid (GABA) content conferring drought resistance. The study suggests that the 200 µmol melatonin treatment shows superior efficacy in enhancing African marigold yield and quality in drought stress conditions.

Exploring Ultrasonic Energy Followed by Natural Fermentation Processing to Enhance Functional Properties and Bioactive Compounds in Millet (Pennisetum glaucum L.) Grains

This study explores the effect of ultrasonic treatment followed by fermentation on the in vitro protein digestibility, protein solubility, functional properties, antioxidant activity, total carotenoid content, and gamma-aminobutyric acid (GABA) levels in millet grains. Ultrasonic treatment was applied at different temperatures (20, 40, and 60 °C). The findings indicated significant improvements in phenolic and flavonoid contents and antioxidant activity in terms of the results of the DPPH, FRAP, and ABTS assays of millet grains after ultrasonic treatment alone or combined with fermentation. Moreover, the carotenoid and GABA contents were found to be significantly higher in the ultrasonic-treated grains. The protein solubility functional properties of the millet grains were also improved after the ultrasonic treatment alone or coupled with the fermentation process. Principal component analysis (PCA) revealed that the combined ultrasonic treatment and fermentation of the millet grains could enhance their antioxidant activity, functional characteristics, and vital compounds. Furthermore, the partial least squares (PLS) validation model emphasised that the ultrasonic treatment of millet at 40 °C, followed by fermentation, is the most optimal treatment among the other treatments. Hence, the conclusions highlight the potential of combined ultrasonic (40 °C) and fermentation treatments to improve grains’ nutritional value and functional properties, making millet more suitable for use in health-promoting food products.

Encapsulation of ɣ-Aminobutyric Acid Compounds Extracted from Germinated Brown Rice by Freeze-Drying Technique.

Gamma-aminobutyric acid (GABA) from plants has several bioactivities, such as neurotransmission, anti-cancer cell proliferation, and blood pressure control. Its bioactivities vary when exposed to pH, heat, and ultraviolet. This study analyzed the protective effect of the GABA encapsulation technique using gum arabic (GA) and maltodextrin (MD) and the freeze-drying method. The impact of different ratios of the wall material GA and MD on morphology, GABA content, antioxidant activity, encapsulation efficiency, process yield, and physical properties were analyzed. Results showed that the structure of encapsulated GABA powder was similar to broken glass pieces of various sizes and irregular shapes. The highest GABA content and encapsulation efficiency were, respectively, 90.77 mg/g and 84.36% when using the wall material GA:MD ratio of 2:2. The encapsulated powder's antioxidant activity was 1.09-1.80 g of encapsulation powder for each formula, which showed no significant difference. GA and MD as the wall material in a 2:2 (w/w) ratio showed the lowest bulk density. The high amount of MD showed the highest Hausner ratio (HR), and Carr's index (CI) showed high encapsulation efficiency and process yield. The stability of encapsulated GABA powder can be kept in clear glass with a screw cap at 35 °C for 42 days compared to the non-encapsulated one, which can be preserved for only 18 days under the same condition. In conclusion, this study demonstrated that the freeze-drying process for GABA encapsulation preserved GABA component extracts from brown rice while increasing its potential beneficial properties. Using a wall material GA:MD ratio of 2:2 resulted in the maximum GABA content, solubility, and encapsulation efficiency while having the lowest bulk density.

Biofilm biofertilizer enhances bioactive compounds including antioxidant activity in hybrid rice grains

Excessive use of chemical fertilizers (CF) in rice cultivation has adversely affected soil and crop productivity and human and environmental health. This has led to the introduction of bio-organic inputs like biofilm biofertilizers (BFBF), which have been shown to increase crop yields and soil quality with reduced CF use. However, the effect of the BFBF on rice grain quality has been understudied. The present study investigated the effect of BFBF on bioactive compounds in rice grains, including antioxidants, which are essential in protecting against diseases related to oxidative stress. The study compared two practices i.e. CF practice and BFBF practice, using six hybrid rice varieties. Harvested grain samples were analyzed for total phenolics (TPC), flavonoids (TFC), and Gamma amino butyric acid (GABA) contents, and antioxidant capacity (TAC). Results showed that the BFBF significantly (p < 0.05) increased TPC, TFC, and GABA in most rice varieties. The TAC was also significantly (p < 0.05) higher (30-200%) in the rice grains produced by the BFBF practice. In conclusion, the BFBF alters the biochemical processes of the rice plant leading to improved medicinal properties showing its potential to produce high-quality rice, which is essential to improve human health.

Optimizing Lactic Acid Bacteria Fermentation for Enhanced Summer and Autumn Tea Quality

The level of consumption of summer tea is a problem in the development of China’s tea industry. Current strategies to enhance the quality of summer and autumn teas primarily target the cultivation environment, with less emphasis on processing improvements. This study aimed to optimize the fermentation parameters to impact the quality of summer and autumn teas. We screened four strains of lactic acid bacteria (LAB) suitable for tea fermentation and determined their optimal mix. This optimized blend was applied to ferment summer and autumn teas. Through single-factor experiments, we evaluated the impact of various processing parameters, including the fixation method, rolling degree, inoculation amount, glucose concentration, fermentation temperature, and fermentation duration, on LAB growth and tea quality. The optimal processing conditions were established as microwave fixation, heavy rolling, an inoculation rate of 1.8% LAB, glucose addition at 8.8%, and fermentation at 36.5 °C for five days. Analysis revealed that the fermentation process significantly reduced the levels of polyphenols and ester-type catechins, which are associated with astringency and bitterness while enhancing the content of gamma-aminobutyric acid (GABA). Specifically, after five days, polyphenol content decreased by 26.89%, and GABA levels increased from 0.051 mg/g to 0.126 mg/g. The predominant aroma compounds in the fermented tea were alcohols with floral and fruity scents, constituting 54.63% of the total aroma profile. This research presents a methodical approach to reduce the astringency and bitterness of summer and autumn teas while concurrently increasing GABA levels.

Chronic Nasal Administration of Kisspeptin-54 Regulates Mood-Related Disorders Via Amygdaloid GABA in Hemi-Parkinsonian Rats

Depression and anxiety, the most prevalent neuropsychiatric manifestations in Parkinson’s disease (PD), negatively impact their quality of life. To determine whether the chronic nasal administration of kisspeptin-54 (KP-54) could. Alleviate symptoms of anxiety and depression in hemi-Parkinsonian rats. Experimental study. This study included adult Sprague Dawley male rats who were administered either a vehicle (artificial cerebrospinal fluid) or 6-hydroxydopamine (6-OHDA) unilaterally into the medial forebrain bundle. The vehicle, or KP-54 (3 nmol/kg, applied topically to the rhinarium), was administered daily for a seven-day period. The sucrose preference test (SPT), elevated plus maze test (EPMT), and open field test (OFT) were implemented to evaluate depression- and anxiety-like behaviors, respectively, seven days following the lesion surgery. Gamma-aminobutyric acid (GABA) concentrations in the amygdala were quantified using mass spectrometry. Tyrosine hydroxylase in substantia nigra was analyzed using immunohistochemistry. The nasal delivery of KP-54 significantly reduced depressionand anxiety-like behaviors that were induced by 6-OHDA, as indicated by the results of the SPT, OFT, and EPMT. Moreover, it was observed that nasal KP-54 effectively mitigated 6-OHDA-induced motor deficits and the loss of nigral dopaminergic neurons. The nasal administration of KP-54 augmented the decline in GABA levels in the amygdala induced by 6-OHDA. Furthermore, effective correlations were established between GABA concentrations and behavioral parameters. The nasal delivery of KP-54 could function as a viable therapeutic alternative for treating mood-related disorders in PD.

Sleep dysfunction and gut dysbiosis related amino acids metabolism disorders in cynomolgus monkeys after middle cerebral artery occlusion

IntroductionThis study aimed to explore the characteristics of post-stroke sleep dysfunction and verify their association with gut dysbiosis and the related amino acid metabolism disorders. This was achieved by using fecal microbiota transplantation (FMT) in a non-human primate stroke model. MethodsTwenty adult male cynomolgus monkeys were divided into the sham (n = 4), middle cerebral artery occlusion (MCAO, n = 5), MCAO + FMT (n = 3), and donor (n = 8) groups. The MCAO+FMT group received FMT at post-MCAO week 4. Sleep parameters, gut microbiota, gamma-aminobutyric acid (GABA), and glutamine (Gln) in the cerebrospinal fluid (CSF) were measured at baseline and postoperative weeks 4, 8, and 12. ResultsAt postoperative weeks 4, 8, and 12, the MCAO group showed decreased sleep efficiency, measured as the percentage of sleep during the whole night (82.3 ± 3.2 % vs 91.3 ± 2.5 %, 79.0 ± 3.75 % vs 90.8 ± 3.2 %, and 69.5 ± 4.8 % vs 90.5 ± 2.7 %; all P < 0.05), lower relative abundance of Lactobacillus (all P < 0.05), and reduced GABA concentrations in the CSF (317.3 ± 30.6 nmol/L vs 437.7 ± 25.6 nmol/L, 303.1 ± 48.9 nmol/L vs 4 40.9 ± 37.8 nmol/L, and 337.9 ± 49.4 nmol/L vs 457.4 ± 39.2 nmol/L; all P < 0.05) compared with the sham group. Sleep efficiency at post-FMT weeks 4 and 8 (84.7 ± 1.1 % vs 79.0 ± 3.75 %, and 84.1 ± 2.0 % vs 69.5 ± 4.8 %; both P < 0.05) and GABA concentration in the CSF at post-FMT week 4 (403.1 ± 25.4 nmol/L vs 303.1 ± 48.9 nmol/L, P < 0.05) was higher in the MCAO+FMT group than in the MCAO group. ConclusionsPost-stroke sleep dysfunction in monkeys is characterized by impaired sleep coherence, associated with decreased levels of probiotics such as Lactobacillus, GABA, and Gln in the CSF and can be ameliorated using FMT.

Gamma-aminobutyric acid as a regulator of astaxanthin production in Haematococcus lacustris under salinity: Exploring physiology, signaling, autophagy, and multi-omics landscape

Haematococcus lacustris-derived natural astaxanthin has significant commercial value, but stressful conditions alone impair cell growth and reduce the total productivity of astaxanthin in industrial settings. This study used gamma-aminobutyric acid (GABA) to increase biomass, astaxanthin productivity, and tolerance to salinity. GABA under NaCl stress enhanced the biomass to 1.76 g/L, astaxanthin content to 30.37 mg g−1, and productivity to 4.10 mg/L d−1, outperforming the control. Further analysis showed GABA enhanced nitrogen assimilation, Ca2+ level, and cellular GABA content, boosting substrate synthesis, energy metabolism, osmoregulation, autophagy, and antioxidant defenses. GABA also activated signaling pathways involving phytohormones, cAMP, cGMP, and MAPK, aiding astaxanthin synthesis. The application of biomarkers (ethylene, salicylic acid, trans-zeatin) and an autophagy inhibitor cooperated with GABA to further enhance the total astaxanthin productivity under NaCl stress. Combining GABA with 25 μM salicylic acid maximized astaxanthin yield at 4.79 mg/L d−1, offering new strategies for industrial astaxanthin production.

Treatment response of venlafaxine induced alterations of gut microbiota and metabolites in a mouse model of depression.

Antidepressants remain the first-line treatment for depression. However, the factors influencing medication response are still unclear. Accumulating evidence implicates an association between alterations in gut microbiota and antidepressant response. Therefore, the aim of this study is to investigate the role of the gut microbiota-brain axis in the treatment response of venlafaxine. After chronic social defeat stress and venlafaxine treatment, mice were divided into responders and non-responders groups. We compared the composition of gut microbiota using 16S ribosomal RNA sequencing. Meanwhile, we quantified metabolomic alterations in serum and hippocampus, as well as hippocampal neurotransmitter levels using liquid chromatography-mass spectrometry. We found that the abundances of 29 amplicon sequence variants (ASVs) were significantly altered between the responders and non-responders groups. These ASVs belonged to 8 different families, particularly Muribaculaceae. Additionally, we identified 38 and 39 differential metabolites in serum and hippocampus between the responders and non-responders groups, respectively. Lipid, amino acid, and purine metabolisms were enriched in both serum and hippocampus. In hippocampus, the concentrations of tryptophan, phenylalanine, gamma-aminobutyric acid, glutamic acid, and glutamine were increased, while the level of succinic acid was decreased in the responders group, compared with the non-responders group. Our findings suggest that the gut microbiota may play a role in the antidepressant effect of venlafaxine by modulating metabolic processes in the central and peripheral tissues. This provides a novel microbial and metabolic framework for understanding the impact of the gut microbiota-brain axis on antidepressant response.

Considerations for event-related gamma-aminobutyric acid functional magnetic resonance spectroscopy.

The use of sequential proton magnetic resonance spectroscopy (MRS) to follow glutamate and gamma-aminobutyric acid (GABA) changes during functional task-based paradigms, functional MRS (fMRS), has increased. This technique has been used to investigate GABA dynamics during both sensory and behavioural tasks, usually with long 'block design' paradigms. Recently, there has been an increase in interest in the use of short stimuli and 'event-related' tasks. While changes in glutamate can be readily followed by collecting multiple individual transients (or shots), measurement of GABA, especially at 3 T, is usually performed using editing techniques like Mescher-Garwood point-resolved spectroscopy (MEGA-PRESS), which by its nature is a dual shot approach. This poses problems when considering an event-related experiment, where it is unclear when GABA may change, or how this may affect the individual subspectra of the MEGA-PRESS acquisition. To address this issue, MEGA-PRESS data were simulated to reflect the effect of a transient change in GABA concentration due to a short event-related stimulus. The change in GABA was simulated for both the ON and OFF subspectra, and the effect of three different conditions (increase only during ON acquisition, increase during OFF acquisition and increase across both) on the corresponding edited GABA spectrum was modelled. Results show that a transient increase in GABA that only occurs during the ON subspectral acquisition, while not changing the results much from when GABA is changed across both conditions, will give a much larger change in the edited GABA spectrum than a transient increase that occurs only during the OFF subspectral acquisition. These results suggest that researchers should think carefully about the design of any event-related fMRS studies using MEGA-PRESS, as well as the analysis of other functional paradigms where transient changes in GABA may be expected. Experimental design considerations are therefore discussed, and suggestions are made.

Examination of acute spin exercise on GABA levels in aging and stroke: The EASE study protocol.

Changes in regional levels of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) may indicate the potential for favorable responses to the treatment of stroke affecting the upper extremity. By selectively altering GABA levels during training, we may induce long-term potentiation and adjust excitatory/inhibitory balance (E/I balance). However, the impact of this alteration may be limited by neural damage or aging. Aerobic exercise has been shown to increase GABA levels in the sensorimotor cortex and improve motor learning by widening the dynamic range of E/I balance. The cross-sectional project, Effects of Acute Exercise on Functional Magnetic Resonance Spectroscopy Measures of GABA in Aging and Chronic Stroke (EASE), is designed to assess the functional relevance of changes in GABA concentration within the sensorimotor cortex before and after an acute aerobic exercise session. EASE will enroll 30 participants comprised of healthy younger adults (18-35 years; n = 10), older adults (60+ years; n = 10), and persons with chronic stroke (n = 10) affecting distal upper extremity function. We will use resting magnetic resonance spectroscopy to measure all participants' GABA levels at rest before and after aerobic exercise. In addition, we will employ functional magnetic resonance spectroscopy using motor skill acquisition and recall tasks in healthy adults. We hypothesize that acute aerobic exercise will increase resting sensorimotor GABA concentration and that higher GABA resting levels will predict better motor learning performance on measures taken both inside and outside the magnet. We also hypothesize that a higher dynamic range of GABA during task-based spectroscopy in healthy adults will predict better motor skill acquisition and recall. The EASE project will evaluate the effect of acute exercise on GABA levels as a biomarker of upper extremity motor skill learning with two populations (aging adults and those with chronic stroke). We predict that acute exercise, higher sensorimotor GABA levels, and broader dynamic range will be related to better motor skill acquisition.