Engineering the intracellular metabolism of Escherichia coli to produce gamma-aminobutyric acid by co-localization of GABA shunt enzymes.

PubMed

Pham, Van Dung; Somasundaram, Sivachandiran; Lee, Seung Hwan; Park, Si Jae; Hong, Soon Ho

2016-02-01

To direct the carbon flux from Krebs cycle into the gamma-aminobutyric acid (GABA) shunt pathway for the production of GABA by protein scaffold introduction in Escherichia coli. Escherichia coli was engineered to produce GABA from glucose by the co-localization of enzymes succinate semialdehyde dehydrogenase (GadD), GABA aminotransferase (PuuE) and GABA transporter (GadC) by protein scaffold. 0.7 g GABA l(-1) was produced from 10 g glucose l(-1) while no GABA was produced in wild type E. coli. pH 6 and 30 °C were optimum for GABA production, and GABA concentration increased to 1.12 g GABA l(-1) when 20 g glucose l(-1) was used. When competing metabolic networks were inactivated, GABA increased by 24 % (0.87 g GABA l(-1)). The novel GABA production system was constructed by co-localization of GABA shunt enzymes.

Submerged fermentation of Lactobacillus rhamnosus YS9 for γ-aminobutyric acid (GABA) production

PubMed Central

Lin, Qian

2013-01-01

γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in central nervous system, and its application in drugs and functional foods has attracted great attention. To enhance production of γ-aminobutyric acid, Lactobacillus rhamnosus YS9, a strain isolated from Chinese traditional fermented food pickled vegetable, was grown under submerged fermentation. Its cultivation conditions were investigated. When culture pH condition was adjusted to the optimal pH of glutamate decarboxylase activity, culture of Lb. rhamnosus YS9 in medium supplemented with 200 mM of monosodium glutamate and 200 μM of pyridoxal phosphate (PLP), produced 187 mM of GABA. PMID:24159304

Maternal Immune Activation Delays Excitatory-to-Inhibitory Gamma-Aminobutyric Acid Switch in Offspring.

PubMed

Corradini, Irene; Focchi, Elisa; Rasile, Marco; Morini, Raffaella; Desiato, Genni; Tomasoni, Romana; Lizier, Michela; Ghirardini, Elsa; Fesce, Riccardo; Morone, Diego; Barajon, Isabella; Antonucci, Flavia; Pozzi, Davide; Matteoli, Michela

2018-04-15

The association between maternal infection and neurodevelopmental defects in progeny is well established, although the biological mechanisms and the pathogenic trajectories involved have not been defined. Pregnant dams were injected intraperitoneally at gestational day 9 with polyinosinic:polycytidylic acid. Neuronal development was assessed by means of electrophysiological, optical, and biochemical analyses. Prenatal exposure to polyinosinic:polycytidylic acid causes an imbalanced expression of the Na + -K + -2Cl - cotransporter 1 and the K + -Cl - cotransporter 2 (KCC2). This results in delayed gamma-aminobutyric acid switch and higher susceptibility to seizures, which endures up to adulthood. Chromatin immunoprecipitation experiments reveal increased binding of the repressor factor RE1-silencing transcription (also known as neuron-restrictive silencer factor) to position 509 of the KCC2 promoter that leads to downregulation of KCC2 transcription in prenatally exposed offspring. Interleukin-1 receptor type I knockout mice, which display braked immune response and no brain cytokine elevation upon maternal immune activation, do not display KCC2/Na + -K + -2Cl - cotransporter 1 imbalance when implanted in a wild-type dam and prenatally exposed. Notably, pretreatment of pregnant dams with magnesium sulfate is sufficient to prevent the early inflammatory state and the delay in excitatory-to-inhibitory switch associated to maternal immune activation. We provide evidence that maternal immune activation hits a key neurodevelopmental process, the excitatory-to-inhibitory gamma-aminobutyric acid switch; defects in this switch have been unequivocally linked to diseases such as autism spectrum disorder or epilepsy. These data open the avenue for a safe pharmacological treatment that may prevent the neurodevelopmental defects caused by prenatal immune activation in a specific pregnancy time window. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc

Further characterization of [3H]gamma-aminobutyric acid release from isolated neuronal growth cones: role of intracellular Ca2+ stores.

PubMed

Lockerbie, R O; Gordon-Weeks, P R

1986-04-01

We have recently shown that growth cones isolated from neonatal rat forebrain possess uptake and release mechanisms for the neurotransmitter gamma-aminobutyric acid. About half of the K+-induced release of [3H]gamma-aminobutyric acid from isolated growth cones is dependent on extracellular Ca2+. The remaining component of the [3H]gamma-aminobutyric acid release is unaffected by removal of extracellular Ca2+ and is resistant to blockade by the voltage-sensitive Ca2+-channel blocker methoxyverapamil. In the present series of experiments we have used caffeine to assess the possible role of intracellular stores of Ca2+ in supporting that component of the K+-induced release of [3H]gamma-aminobutyric acid from isolated growth cones that is independent of extracellular Ca2+. We have chosen caffeine because of its well established effect of releasing Ca2+ from smooth endoplasmic reticulum in muscle. We found that caffeine can release [3H]gamma-aminobutyric acid from isolated growth cones. This effect persists in Ca2+-free medium, in the presence of methoxyverapamil and in the absence of Na+. Furthermore, isobutylmethylxanthine could not substitute for caffeine suggesting that the caffeine effect is not due to phosphodiesterase inhibition and the subsequent rise in intracellular cyclic nucleotides. A combination of the mitochondrial poisons, Antimycin A and sodium azide had no effect on the release of [3H]gamma-aminobutyric acid induced either by caffeine or by high K+. We conclude that caffeine causes the release of Ca2+ from a non-mitochondrial store within the growth cone and that this Ca2+ store supports that component of the K+-induced release of [3H]gamma-aminobutyric acid that is independent of extracellular Ca2+.

Determination and comparison of γ-aminobutyric acid (GABA) content in pu-erh and other types of Chinese tea.

PubMed

Zhao, Ming; Ma, Yan; Wei, Zhen-zhen; Yuan, Wen-xia; Li, Ya-li; Zhang, Chun-hua; Xue, Xiao-ting; Zhou, Hong-jie

2011-04-27

Two previous studies have reported that pu-erh tea contains a high level of γ-aminobutyric acid (GABA), which is the major inhibitory neurotransmitter in the central nervous system and has several physiological functions. However, two other researchers have demonstrated that the GABA content of several pu-erh teas was low. Due to the high value and health benefits of GABA, analysis of mass-produced pu-erh tea is necessary to determine whether it is actually enriched with GABA. A high-performance liquid chromatography (HPLC) method was developed for the determination of GABA in tea, the results of which were verified by amino acid analysis using an Amino Acid Analyzer (AAA). A total of 114 samples of various types of Chinese tea, including 62 pu-erh teas, 13 green teas, 8 oolong teas, 8 black teas, 3 white teas, 4 GABA teas, and 16 process samples from two industrial fermentations of pu-erh tea (including the raw material and the first to seventh turnings), were analyzed using HPLC. Statistical analysis demonstrated that the GABA content in pu-erh tea was significantly lower than that in other types of tea (p < 0.05) and that the GABA content decreased during industrial fermentation of pu-erh tea (p < 0.05). This mass analysis and comparison suggested GABA was not a major bioactive constituent and resolved the disagreement GABA content in pu-erh tea. In addition, the GABA content in white tea was found to be significantly higher than that in the other types of tea (p < 0.05), leading to the possibility of producing GABA-enriched white tea.

Design and mechanism of tetrahydrothiophene-based γ-aminobutyric acid aminotransferase inactivators.

PubMed

Le, Hoang V; Hawker, Dustin D; Wu, Rui; Doud, Emma; Widom, Julia; Sanishvili, Ruslan; Liu, Dali; Kelleher, Neil L; Silverman, Richard B

2015-04-08

Low levels of γ-aminobutyric acid (GABA), one of two major neurotransmitters that regulate brain neuronal activity, are associated with many neurological disorders, such as epilepsy, Parkinson's disease, Alzheimer's disease, Huntington's disease, and cocaine addiction. One of the main methods to raise the GABA level in human brain is to use small molecules that cross the blood-brain barrier and inhibit the activity of γ-aminobutyric acid aminotransferase (GABA-AT), the enzyme that degrades GABA. We have designed a series of conformationally restricted tetrahydrothiophene-based GABA analogues with a properly positioned leaving group that could facilitate a ring-opening mechanism, leading to inactivation of GABA-AT. One compound in the series is 8 times more efficient an inactivator of GABA-AT than vigabatrin, the only FDA-approved inactivator of GABA-AT. Our mechanistic studies show that the compound inactivates GABA-AT by a new mechanism. The metabolite resulting from inactivation does not covalently bind to amino acid residues of GABA-AT but stays in the active site via H-bonding interactions with Arg-192, a π-π interaction with Phe-189, and a weak nonbonded S···O═C interaction with Glu-270, thereby inactivating the enzyme.

Brain gamma-aminobutyric acid deficiency in dialysis encephalopathy.

PubMed

Sweeney, V P; Perry, T L; Price, J D; Reeve, C E; Godolphin, W J; Kish, S J

1985-02-01

We measured levels of gamma-aminobutyric acid (GABA) in the CSF and in the autopsied brain of patients with dialysis encephalopathy. GABA concentrations were low in the CSF of three of five living patients. Mean GABA content was reduced by 30 to 50% in five brain regions (frontal, occipital, and cerebellar cortex, caudate nucleus, and medial dorsal thalamus) in five fatal cases. GABA content was normal in brain regions where GABA is characteristically reduced in Huntington's disease. Choline acetyltransferase activity was diminished (by 25 to 35%) in cerebral cortex of the dialysis encephalopathy patients.

Effects of γ-Aminobutyric Acid A Receptor Activation on Counterregulatory Responses to Subsequent Exercise in Individuals With Type 1 Diabetes

PubMed Central

Hedrington, Maka S.; Mikeladze, Maia; Tate, Donna B.; Younk, Lisa M.; Davis, Ian

2016-01-01

The effects of γ-aminobutyric acid (GABA) A receptor activation on physiologic responses during next-day exercise in type 1 diabetes are unknown. To test the hypothesis that GABA A activation with the benzodiazepine alprazolam would blunt counterregulatory responses during subsequent exercise, 29 (15 male, 14 female) individuals with type 1 diabetes (HbA1c 7.8 ± 1%) were studied during separate 2-day protocols. Day 1 consisted of morning and afternoon 2-h euglycemic or 2.9 mmol/L hypoglycemic clamps with or without 1 mg alprazolam given 30 min before each clamp. Day 2 consisted of a 90-min euglycemic cycling exercise at 50% VO2max. Tritiated glucose was used to measure glucose kinetics. Despite equivalent day 2 insulin (93 ± 6 pmol/L) and glucose levels (5.3 ± 0.1 mmol/L), plasma epinephrine, norepinephrine, glucagon, cortisol, and growth hormone responses were similarly reduced after alprazolam or day 1 hypoglycemia compared with euglycemic control. Endogenous glucose production, lipolysis (glycerol, nonesterified fatty acid), and glycogenolysis (lactate) were also reduced during day 2 exercise after day 1 GABA A activation. We conclude that activation of GABA A receptors with alprazolam can result in widespread neuroendocrine, autonomic nervous system, and metabolic counterregulatory failure during subsequent submaximal exercise and may increase the risk of exercise-associated hypoglycemia in individuals with type 1 diabetes. PMID:27217489

Design and Mechanism of Tetrahydrothiophene-Based γ-Aminobutyric Acid Aminotransferase Inactivators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le, Hoang V.; Hawker, Dustin D.; Wu, Rui

Low levels of gamma-aminobutyric acid (GABA), one of two major neurotransmitters that regulate brain neuronal activity, are associated with many neurological disorders, such as epilepsy, Parkinsons disease, Alzheimers disease, Huntingtons disease, and cocaine addiction. One of the main methods to raise the GABA level in human brain is to use small molecules that cross the bloodbrain barrier and inhibit the activity of gamma-aminobutyric acid aminotransferase (GABA-AT), the enzyme that degrades GABA. We have designed a series of conformationally restricted tetrahydrothiophene-based GABA analogues with a properly positioned leaving group that could facilitate a ring-opening mechanism, leading to inactivation of GABA-AT. Onemore » compound in the series is 8 times more efficient an inactivator of GABA-AT than vigabatrin, the only FDA-approved inactivator of GABA-AT. Our mechanistic studies show that the compound inactivates GABA-AT by a new mechanism. The metabolite resulting from inactivation does not covalently bind to amino acid residues of GABA-AT but stays in the active site via H-bonding interactions with Arg-192, a pi-pi interaction with Phe-189, and a weak nonbonded (SO)-O-...=C interaction with Glu-270, thereby inactivating the enzyme.« less

Regulating the Efficacy of Inhibition Through Trafficking of γ-Aminobutyric Acid Type A Receptors.

PubMed

Vien, Thuy N; Moss, Stephen J; Davies, Paul A

2016-11-01

Trafficking of anesthetic-sensitive receptors within the plasma membrane, or from one cellular component to another, occurs continuously. Changes in receptor trafficking have implications in altering anesthetic sensitivity. γ-Aminobutyric acid type A receptors (GABAARs) are anion-permeable ion channels and are the major class of receptor in the adult mammalian central nervous system that mediates inhibition. GABAergic signaling allows for precise synchronized firing of action potentials within brain circuits that is critical for cognition, behavior, and consciousness. This precision depends upon tightly controlled trafficking of GABAARs into the membrane. General anesthetics bind to and allosterically enhance GABAARs by prolonging the open state of the receptor and thereby altering neuronal and brain circuit activity. Subunit composition and GABAAR localization strongly influence anesthetic end points; therefore, changes in GABAAR trafficking could have significant consequences to anesthetic sensitivity. GABAARs are not static membrane structures but are in a constant state of flux between extrasynaptic and synaptic locations and are continually endocytosed and recycled from and to the membrane. Neuronal activity, posttranslational modifications, and some naturally occurring and synthetic compounds can influence the expression and trafficking of GABAARs. In this article, we review GABAARs, their trafficking, and how phosphorylation of GABAAR subunits can influence the surface expression and function of the receptor. Ultimately, alterations of GABAAR trafficking could modify anesthetic end points, both unintentionally through pathologic processes but potentially as a therapeutic target to adjust anesthetic-sensitive GABAARs.

cAMP and forskolin decrease. gamma. -aminobutyric acid-gated chloride flux in rat brain synaptoneurosomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heuschneider, G.; Schwartz, R.D.

1989-04-01

The effects of the cyclic nucleotide cAMP on {gamma}-aminobutyric acid-gated chloride channel function were investigated. The membrane-permeant cAMP analog N{sup 6}, O{sup 2{prime}}-dibutyryladenosine 3{prime},5{prime}-cyclic monophosphate inhibited muscimol-induced {sup 36}Cl{sup {minus}} uptake into rat cerebral cortical synaptoneurosomes in a concentration-dependent manner. The inhibition was due to a decrease in the maximal effect of muscimol, with no change in potency. Similar effects were observed with 8-(4-chlorophenylthio)adenosine 3{prime},5{prime}-cyclic monophosphate, 8-bromoadenosine 3{prime},5{prime}-cyclic monophosphate, and the phosphodiesterase inhibitor isobutylmethylxanthine. The effect of endogenous cAMP accumulation on the {gamma}-aminobutyric acid-gated Cl{sup {minus}} channel was studied with forskolin, an activator of adenylate cyclase. Under identical conditions, inmore » the intact synaptoneurosomes, forskolin inhibited muscimol-induced {sup 36}Cl{sup {minus}} uptake and generated cAMP with similar potencies. Surprisingly, 1,9-dideoxyforskolin, which does not activate adenylate cyclase, also inhibited the muscimol response, suggesting that forskolin and its lipophilic derivatives may interact with the Cl{sup {minus}} channel directly. The data suggest that {gamma}-aminobutyric acid (GABA{sub A}) receptor function in brain can be regulated by cAMP-dependent phosphorylation.« less

Production of gamma-aminobutyric acid from glucose by introduction of synthetic scaffolds between isocitrate dehydrogenase, glutamate synthase and glutamate decarboxylase in recombinant Escherichia coli.

PubMed

Pham, Van Dung; Lee, Seung Hwan; Park, Si Jae; Hong, Soon Ho

2015-08-10

Escherichia coli were engineered for the direct production of gamma-aminobutyric acid from glucose by introduction of synthetic protein scaffold. In this study, three enzymes consisting GABA pathway (isocitrate dehydrogenase, glutamate synthase and glutamate decarboxylase) were connected via synthetic protein scaffold. By introduction of scaffold, 0.92g/L of GABA was produced from 10g/L of glucose while no GABA was produced in wild type E. coli. The optimum pH and temperature for GABA production were 4.5 and 30°C, respectively. When competing metabolic network was inactivated by knockout mutation, maximum GABA concentration of 1.3g/L was obtained from 10g/L glucose. The recombinant E. coli strain which produces GABA directly from glucose was successfully constructed by introduction of protein scaffold. Copyright © 2015 Elsevier B.V. All rights reserved.

Antisera to gamma-aminobutyric acid. I. Production and characterization using a new model system.

PubMed

Hodgson, A J; Penke, B; Erdei, A; Chubb, I W; Somogyi, P

1985-03-01

Antisera to the amino acid gamma-aminobutyric acid (GABA) have been developed with the aim of immunohistochemical visualization of neurons that use it as a neurotransmitter. GABA bound to bovine serum albumin was the immunogen. The reactivities of the sera to GABA and a variety of structurally related compounds were tested by coupling these compounds to nitrocellulose paper activated with polylysine and glutaraldehyde and incubating the paper with the unlabeled antibody enzyme method, thus simulating immunohistochemistry of tissue sections. The antisera did not react with L-glutamate, L-aspartate, D-aspartate, glycine, taurine, L-glutamine, L-lysine, L-threonine, L-alanine, alpha-aminobutyrate, beta-aminobutyrate, putrescine, or delta-aminolevulinate. There was cross-reaction with gamma-amino-beta-hydroxybutyrate, 1-10%, and the homologues of GABA: beta-alanine, 1-10%, delta-aminovalerate, approximately 10%, and epsilon-amino-caproate, approximately 10%. The antisera reacted slightly with the dipeptide gamma-aminobutyrylleucine, but not carnosine or homocarnosine. Immunostaining of GABA was completely abolished by adsorption of the sera to GABA coupled to polyacrylamide beads by glutaraldehyde. The immunohistochemical model is simple, amino acids and peptides are bound in the same way as in aldehyde-fixed tissue and, in contrast to radioimmunoassay, it uses an immunohistochemical detection system. This method has enabled us to define the high specificity of anti-GABA sera and to use them in some novel ways. The model should prove useful in assessing the specificity of other antisera.

γ-Aminobutyric acid ameliorates fluoride-induced hypothyroidism in male Kunming mice.

PubMed

Yang, Haoyue; Xing, Ronge; Liu, Song; Yu, Huahua; Li, Pengcheng

2016-02-01

This study evaluated the protective effects of γ-aminobutyric acid (GABA), a non-protein amino acid and anti-oxidant, against fluoride-induced hypothyroidism in mice. Light microscope sample preparation technique and TEM sample preparation technique were used to assay thyroid microstructure and ultrastructure; enzyme immunoassay method was used to assay hormone and protein levels; immunohistochemical staining method was used to assay apoptosis of thyroid follicular epithelium cells. Subacute injection of sodium fluoride (NaF) decreased blood T4, T3 and thyroid hormone-binding globulin (TBG) levels to 33.98 μg/l, 3 2.8 ng/ml and 11.67 ng/ml, respectively. In addition, fluoride intoxication induced structural abnormalities in thyroid follicles. Our results showed that treatment of fluoride-exposed mice with GABA appreciably decreased metabolic toxicity induced by fluoride and restored the microstructural and ultrastructural organisation of the thyroid gland towards normalcy. Compared with the negative control group, GABA treatment groups showed significantly upregulated T4, T3 and TBG levels (42.34 μg/l, 6.54 ng/ml and 18.78 ng/ml, respectively; P<0.05), properly increased TSH level and apoptosis inhibition in thyroid follicular epithelial cells. To the best of our knowledge, this is the first study to establish the therapeutic efficacy of GABA as a natural antioxidant in inducing thyroprotection against fluoride-induced toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

Phenibut (β-Phenyl-γ-aminobutyric Acid) Dependence and Management of Withdrawal: Emerging Nootropics of Abuse.

PubMed

Ahuja, Tania; Mgbako, Ofole; Katzman, Caroline; Grossman, Allison

2018-01-01

This case report describes the development of withdrawal from phenibut, a gamma-aminobutyric acid-receptor type B agonist. Although phenibut is not an FDA-approved medication, it is available through online retailers as a nootropic supplement. There are reports of dependence in patients that misuse phenibut. We report a case in which a patient experienced withdrawal symptoms from phenibut and was successfully treated with a baclofen taper. This case report highlights the development of phenibut use disorder with coingestion of alcohol and potential management for phenibut withdrawal. We believe clinicians must be aware of how phenibut dependence may present and how to manage the withdrawal syndrome.

The gamma-aminobutyric acid type B (GABAB) receptor agonist baclofen inhibits morphine sensitization by decreasing the dopamine level in rat nucleus accumbens

PubMed Central

2012-01-01

Background Repeated morphine exposure can induce behavioral sensitization. There are evidences have shown that central gamma-aminobutyric acid (GABA) system is involved in morphine dependence. However, the effect of a GABAB receptor agonist baclofen on morphine-induced behavioral sensitization in rats is unclear. Methods We used morphine-induced behavioral sensitization model in rat to investigate the effects of baclofen on behavioral sensitization. Moreover, dopamine release in the shell of the nucleus accumbens was evaluated using microdialysis assay in vivo. Results The present study demonstrated that morphine challenge (3 mg/kg, s.c.) obviously enhanced the locomotor activity following 4-day consecutive morphine administration and 3-day withdrawal period, which indicated the expression of morphine sensitization. In addition, chronic treatment with baclofen (2.5, 5 mg/kg) significantly inhibited the development of morphine sensitization. It was also found that morphine challenge 3 days after repeated morphine administration produced a significant increase of extracellular dopamine release in nucleus accumbens. Furthermore, chronic treatment with baclofen decreased the dopamine release induced by morphine challenge. Conclusions Our results indicated that gamma-aminobutyric acid system plays an important role in the morphine sensitization in rat and suggested that behavioral sensitization is a promising model to study the mechanism underlying drug abuse. PMID:22559224

The γ-aminobutyric acid type B (GABAB) receptor agonist baclofen inhibits morphine sensitization by decreasing the dopamine level in rat nucleus accumbens.

PubMed

Fu, Zhenyu; Yang, Hongfa; Xiao, Yuqiang; Zhao, Gang; Huang, Haiyan

2012-07-10

Repeated morphine exposure can induce behavioral sensitization. There are evidences have shown that central gamma-aminobutyric acid (GABA) system is involved in morphine dependence. However, the effect of a GABAB receptor agonist baclofen on morphine-induced behavioral sensitization in rats is unclear. We used morphine-induced behavioral sensitization model in rat to investigate the effects of baclofen on behavioral sensitization. Moreover, dopamine release in the shell of the nucleus accumbens was evaluated using microdialysis assay in vivo. The present study demonstrated that morphine challenge (3 mg/kg, s.c.) obviously enhanced the locomotor activity following 4-day consecutive morphine administration and 3-day withdrawal period, which indicated the expression of morphine sensitization. In addition, chronic treatment with baclofen (2.5, 5 mg/kg) significantly inhibited the development of morphine sensitization. It was also found that morphine challenge 3 days after repeated morphine administration produced a significant increase of extracellular dopamine release in nucleus accumbens. Furthermore, chronic treatment with baclofen decreased the dopamine release induced by morphine challenge. Our results indicated that gamma-aminobutyric acid system plays an important role in the morphine sensitization in rat and suggested that behavioral sensitization is a promising model to study the mechanism underlying drug abuse.

Synaptic inhibition and γ-aminobutyric acid in the mammalian central nervous system

PubMed Central

OBATA, Kunihiko

2013-01-01

Signal transmission through synapses connecting two neurons is mediated by release of neurotransmitter from the presynaptic axon terminals and activation of its receptor at the postsynaptic neurons. γ-Aminobutyric acid (GABA), non-protein amino acid formed by decarboxylation of glutamic acid, is a principal neurotransmitter at inhibitory synapses of vertebrate and invertebrate nervous system. On one hand glutamic acid serves as a principal excitatory neurotransmitter. This article reviews GABA researches on; (1) synaptic inhibition by membrane hyperpolarization, (2) exclusive localization in inhibitory neurons, (3) release from inhibitory neurons, (4) excitatory action at developmental stage, (5) phenotype of GABA-deficient mouse produced by gene-targeting, (6) developmental adjustment of neural network and (7) neurological/psychiatric disorder. In the end, GABA functions in simple nervous system and plants, and non-amino acid neurotransmitters were supplemented. PMID:23574805

cAMP and forskolin decrease gamma-aminobutyric acid-gated chloride flux in rat brain synaptoneurosomes.

PubMed Central

Heuschneider, G; Schwartz, R D

1989-01-01

The effects of the cyclic nucleotide cAMP on gamma-aminobutyric acid-gated chloride channel function were investigated. The membrane-permeant cAMP analog N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate inhibited muscimol-induced 36Cl- uptake into rat cerebral cortical synaptoneurosomes in a concentration-dependent manner (IC50 = 1.3 mM). The inhibition was due to a decrease in the maximal effect of muscimol, with no change in potency. Similar effects were observed with 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate, 8-bromoadenosine 3',5'-cyclic monophosphate, and the phosphodiesterase inhibitor isobutylmethylxanthine. The effect of endogenous cAMP accumulation on the gamma-aminobutyric acid-gated Cl- channel was studied with forskolin, an activator of adenylate cyclase. Under identical conditions, in the intact synaptoneurosomes, forskolin inhibited muscimol-induced 36Cl- uptake and generated cAMP with similar potencies (IC50 = 14.3 microM; EC50 = 6.2 microM, respectively). Surprisingly, 1,9-dideoxyforskolin, which does not activate adenylate cyclase, also inhibited the muscimol response, suggesting that forskolin and its lipophilic derivatives may interact with the Cl- channel directly. Indeed, forskolin inhibition of muscimol-induced 36Cl- uptake was extremely rapid (within 5 sec), preceding the accumulation of sufficient levels of cAMP. After 5 min, a slower phase of inhibition was seen, similar to the time course for cAMP accumulation. The data suggest that gamma-aminobutyric acid (GABAA) receptor function in brain can be regulated by cAMP-dependent phosphorylation. PMID:2468163

Proteomic analysis of drought resistance in crabapple seedlings primed by the xenobiotic Beta-aminobutyric acid

USDA-ARS?s Scientific Manuscript database

In a variety of annual crops and model plants, the xenobiotic DL-Beta-aminobutyric acid (BABA) has been shown to enhance disease resistance and increase salt, drought and thermotolerance. BABA does not activate stress genes directly, but sensitizes plants to respond more quickly and strongly to biot...

Attenuated sensitivity to neuroactive steroids in γ-aminobutyrate type A receptor delta subunit knockout mice

PubMed Central

Mihalek, Robert M.; Banerjee, Pradeep K.; Korpi, Esa R.; Quinlan, Joseph J.; Firestone, Leonard L.; Mi, Zhi-Ping; Lagenaur, Carl; Tretter, Verena; Sieghart, Werner; Anagnostaras, Stephan G.; Sage, Jennifer R.; Fanselow, Michael S.; Guidotti, Alessandro; Spigelman, Igor; Li, Zhiwei; DeLorey, Timothy M.; Olsen, Richard W.; Homanics, Gregg E.

1999-01-01

γ-Aminobutyric acid (GABA) type A receptors mediate fast inhibitory synaptic transmission and have been implicated in responses to sedative/hypnotic agents (including neuroactive steroids), anxiety, and learning and memory. Using gene targeting technology, we generated a strain of mice deficient in the δ subunit of the GABA type A receptors. In vivo testing of various behavioral responses revealed a strikingly selective attenuation of responses to neuroactive steroids, but not to other modulatory drugs. Electrophysiological recordings from hippocampal slices revealed a significantly faster miniature inhibitory postsynaptic current decay time in null mice, with no change in miniature inhibitory postsynaptic current amplitude or frequency. Learning and memory assessed with fear conditioning were normal. These results begin to illuminate the novel contributions of the δ subunit to GABA pharmacology and sedative/hypnotic responses and behavior and provide insights into the physiology of neurosteroids. PMID:10536021

Formation of [b3 - 1 + cat]+ ions from metal-cationized tetrapeptides containing beta-alanine, gamma-aminobutyric acid or epsilon-aminocaproic acid residues.

PubMed

Osburn, Sandra M; Ochola, Sila O; Talaty, Erach R; Van Stipdonk, Michael J

2008-11-01

The presence and position of a single beta-alanine (betaA), gamma-aminobutyric acid (gammaABu) or epsilon-aminocaproic acid (Cap) residue has been shown to have a significant influence on the formation of b(n)+ and y(n)+ product ions from a series of model, protonated peptides. In this study, we examined the effect of the same residues on the formation of analogous [b3 - 1 + cat]+ products from metal (Li+, Na+ and Ag+)-cationized peptides. The larger amino acids suppress formation of b3+ from protonated peptides with general sequence AAXG (where X = beta-alanine, gamma-aminobutyric acid or epsilon-aminocaproic acid), presumably because of the prohibitive effect of larger cyclic intermediates in the 'oxazolone' pathway. However, abundant [b3 - 1 + cat]+ products are generated from metal-cationized versions of AAXG. Using a group of deuterium-labeled and exchanged peptides, we found that formation of [b3 - 1 + cat]+ involves transfer of either amide or alpha-carbon position H atoms, and the tendency to transfer the atom from the alpha-carbon position increases with the size of the amino acid in position X. To account for the transfer of the H atom, a mechanism involving formation of a ketene product as [b3 - 1 + cat]+ is proposed.

Determination of gamma-aminobutyric acid in food matrices by isotope dilution hydrophilic interaction chromatography coupled to mass spectrometry.

PubMed

Zazzeroni, Raniero; Homan, Andrew; Thain, Emma

2009-08-01

The estimation of the dietary intake of gamma-aminobutyric acid (GABA) is dependent upon the knowledge of its concentration values in food matrices. To this end, an isotope dilution liquid chromatography-mass spectrometry method has been developed employing the hydrophilic interaction chromatography technique for analyte separation. This approach enabled accurate quantification of GABA in apple, potato, soybeans, and orange juice without the need of a pre- or post-column derivatization reaction. A selective and precise analytical measurement has been obtained with a triple quadrupole mass spectrometer operating in multiple reaction monitoring using the method of standard additions and GABA-d(6) as an internal standard. The concentrations of GABA found in the matrices tested are 7 microg/g of apple, 342 microg/g of potatoes, 211 microg/g of soybeans, and 344 microg/mL of orange juice.

Effects of γ-Aminobutyric acid transporter 1 inhibition by tiagabine on brain glutamate and γ-Aminobutyric acid metabolism in the anesthetized rat In vivo.

PubMed

Patel, Anant B; de Graaf, Robin A; Rothman, Douglas L; Behar, Kevin L

2015-07-01

γ-Aminobutyric acid (GABA) clearance from the extracellular space after release from neurons involves reuptake into terminals and astrocytes through GABA transporters (GATs). The relative flows through these two pathways for GABA released from neurons remains unclear. This study determines the effect of tiagabine, a selective inhibitor of neuronal GAT-1, on the rates of glutamate (Glu) and GABA metabolism and GABA resynthesis via the GABA-glutamine (Gln) cycle. Halothane-anesthetized rats were administered tiagabine (30 mg/kg, i.p.) and 45 min later received an intravenous infusion of either [1,6-(13)C2]glucose (in vivo) or [2-(13)C]acetate (ex vivo). Nontreated rats served as controls. Metabolites and (13)C enrichments were measured with (1)H-[(13)C]-nuclear magnetic resonance spectroscopy and referenced to their corresponding endpoint values measured in extracts from in situ frozen brain. Metabolic flux estimates of GABAergic and glutamatergic neurons were determined by fitting a metabolic model to the (13)C turnover data measured in vivo during [1,6-(13)C2]glucose infusion. Tiagabine-treated rats were indistinguishable (P > 0.05) from controls in tissue amino acid levels and in (13)C enrichments from [2-(13)C]acetate. Tiagabine reduced average rates of glucose oxidation and neurotransmitter cycling in both glutamatergic neurons (↓18%, CMR(glc(ox)Glu): control, 0.27 ± 0.05 vs. tiagabine, 0.22 ± 0.04 µmol/g/min; ↓11%, V(cyc(Glu-Gln)): control 0.23 ± 0.05 vs. tiagabine 0.21 ± 0.04 µmol/g/min and GABAergic neurons (↓18-25%, CMR(glc(ox)GABA): control 0.09 ± 0.02 vs. tiagabine 0.07 ± 0.03 µmol/g/min; V(cyc(GABA-Gln)): control 0.08 ± 0.02 vs. tiagabine 0.07 ± 0.03 µmol/g/min), but the changes in glutamatergic and GABAergic fluxes were not significant (P > 0.10). The results suggest that any reduction in GABA metabolism by tiagabine might be an indirect response to reduced glutamatergic drive rather than direct compensatory effects. © 2015 Wiley

Grp94 Protein Delivers γ-Aminobutyric Acid Type A (GABAA) Receptors to Hrd1 Protein-mediated Endoplasmic Reticulum-associated Degradation.

PubMed

Di, Xiao-Jing; Wang, Ya-Juan; Han, Dong-Yun; Fu, Yan-Lin; Duerfeldt, Adam S; Blagg, Brian S J; Mu, Ting-Wei

2016-04-29

Proteostasis maintenance of γ-aminobutyric acid type A (GABAA) receptors dictates their function in controlling neuronal inhibition in mammalian central nervous systems. However, as a multisubunit, multispan, integral membrane protein, even wild type subunits of GABAA receptors fold and assemble inefficiently in the endoplasmic reticulum (ER). Unassembled and misfolded subunits undergo ER-associated degradation (ERAD), but this degradation process remains poorly understood for GABAA receptors. Here, using the α1 subunits of GABAA receptors as a model substrate, we demonstrated that Grp94, a metazoan-specific Hsp90 in the ER lumen, uses its middle domain to interact with the α1 subunits and positively regulates their ERAD. OS-9, an ER-resident lectin, acts downstream of Grp94 to further recognize misfolded α1 subunits in a glycan-dependent manner. This delivers misfolded α1 subunits to the Hrd1-mediated ubiquitination and the valosin-containing protein-mediated extraction pathway. Repressing the initial ERAD recognition step by inhibiting Grp94 enhances the functional surface expression of misfolding-prone α1(A322D) subunits, which causes autosomal dominant juvenile myoclonic epilepsy. This study clarifies a Grp94-mediated ERAD pathway for GABAA receptors, which provides a novel way to finely tune their function in physiological and pathophysiological conditions. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

[The interaction between gamma-aminobutyric acid and other related neurotransmitters in depression].

PubMed

Li, Zhen; An, Shu-Cheng; Li, Jiang-Na

2014-06-01

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter of the central nervous system (CNS) in mammalian, which involved in several mood disorders such as anxiety, depression and schizophrenia. Nowadays, there are growing evidences showed that the depression is concerned with a deficiency in brain GABA. However, there are numerous studies based on the monoamine hypothesis and glutamatergic dysfunction, while the study on GABA is relatively less and scattered. Our aim is to discuss the relationship between depression and GABA by introducing the role of GABA receptors and the interaction between GABA and 5-hydroxytryptamine, dopamine and glutamic acid. It provides new ideas for further study on the pathogenesis and therapy of depression.

Phosphatase inhibitors remove the run-down of γ-aminobutyric acid type A receptors in the human epileptic brain

PubMed Central

Palma, E.; Ragozzino, D. A.; Di Angelantonio, S.; Spinelli, G.; Trettel, F.; Martinez-Torres, A.; Torchia, G.; Arcella, A.; Di Gennaro, G.; Quarato, P. P.; Esposito, V.; Cantore, G.; Miledi, R.; Eusebi, F.

2004-01-01

The properties of γ-aminobutyric acid (GABA) type A receptors (GABAA receptors) microtransplanted from the human epileptic brain to the plasma membrane of Xenopus oocytes were compared with those recorded directly from neurons, or glial cells, in human brains slices. Cell membranes isolated from brain specimens, surgically obtained from six patients afflicted with drug-resistant temporal lobe epilepsy (TLE) were injected into frog oocytes. Within a few hours, these oocytes acquired GABAA receptors that generated GABA currents with an unusual run-down, which was inhibited by orthovanadate and okadaic acid. In contrast, receptors derived from membranes of a nonepileptic hippocampal uncus, membranes from mouse brain, or recombinant rat α1β2γ2-GABA receptors exhibited a much less pronounced GABA-current run-down. Moreover, the GABAA receptors of pyramidal neurons in temporal neocortex slices from the same six epileptic patients exhibited a stronger run-down than the receptors of rat pyramidal neurons. Interestingly, the GABAA receptors of neighboring glial cells remained substantially stable after repetitive activation. Therefore, the excessive GABA-current run-down observed in the membrane-injected oocytes recapitulates essentially what occurs in neurons, rather than in glial cells. Quantitative RT-PCR analyses from the same TLE neocortex specimens revealed that GABAA-receptor β1, β2, β3, and γ2 subunit mRNAs were significantly overexpressed (8- to 33-fold) compared with control autopsy tissues. Our results suggest that an abnormal GABA-receptor subunit transcription in the TLE brain leads to the expression of run-down-enhanced GABAA receptors. Blockage of phosphatases stabilizes the TLE GABAA receptors and strengthens GABAergic inhibition. It may be that this process can be targeted to develop new treatments for intractable epilepsy. PMID:15218107

Phenotypic consequences of deletion of the {gamma}{sub 3}, {alpha}{sub 5}, or {beta}{sub 3} subunit of the type A {gamma}-aminobutyric acid receptor in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Culia, C.T.; Stubbs, L.J.; Montgomery, C.S.

1994-03-29

Three genes (Gabrg3, Gabra5, and Gabrb3) encoding the {gamma}{sub 3}, {alpha}{sub 5}, and {beta}{sub 3} subunits of the type A {gamma}-aminobutyric acid receptor, respectively, are known to map near the pink-eyed dilution (p) locus in mouse chromosome 7. This region shares homology with a segment of human chromosome 15 that is implicated in Angelman syndrome, an inherited neurobehavioral disorder. By mapping Gabrg3-Gabra5-Gabrb3-telomere. Like Gabrb3, neither the Gabra5 nor Gabrg3 gene is functionally imprinted in adult mouse brain. Mice deleted for all three subunits die at birth with a cleft palate, although there are rare survivors ({approximately} 5%) that do notmore » have a cleft palate but do exhibit a neurological abnormality characterized by tremor, jerky gait, and runtiness. The authors have previously suggested that deficiency of the {beta}{sub 3} subunit may be responsible for the clefting defect. Most notably, however, in this report they describe mice carrying two overlapping, complementing p deletions that fail to express the {gamma}{sub 3} transcript, as well as mice from another line that express neither the {gamma}{sub 3} nor {alpha}{sub 5} transcripts. Surprisingly, mice from both of these lines are phenotypically normal and do not exhibit any of the neurological symptoms characteristic of the rare survivors that are deleted for all three ({gamma}{sub 3}, {alpha}{sub 5}, and {beta}{sub 3}) subunits. These mice therefore provide a whole-organism type A {gamma}-aminobutyric-acid receptor background that is devoid of any receptor subtypes that normally contain the {gamma}{sub 3} and/or {alpha}{sub 5} subunits. The absence of an overt neurological phenotype in mice lacking the {gamma}{sub 3} and/or {alpha}{sub 5} subunits also suggests that mutations in these genes are unlikely to provide useful animal models for Angelman syndrome in humans.« less

Gamma-aminobutyric acid fermentation with date residue by a lactic acid bacterium, Lactobacillus brevis.

PubMed

Hasegawa, Momoko; Yamane, Daisuke; Funato, Kouichi; Yoshida, Atsushi; Sambongi, Yoshihiro

2018-03-01

Dates are commercially consumed as semi-dried fruit or processed into juice and puree for further food production. However, the date residue after juice and puree production is not used, although it appears to be nutrient enriched. Here, date residue was fermented by a lactic acid bacterium, Lactobacillus brevis, which has been generally recognized as safe. Through degradation of sodium glutamate added to the residue during the fermentation, γ-aminobutyric acid (GABA), which reduces neuronal excitability, was produced at the conversion rate of 80-90% from glutamate. In order to achieve this GABA production level, pretreatment of the date residue with carbohydrate-degrading enzymes, i.e., cellulase and pectinase, was necessary. All ingredients used for this GABA fermentation were known as being edible. These results provide us with a solution for the increasing commercial demand for GABA in food industry with the use of date residue that has been often discarded. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Production of gaba (γ - Aminobutyric acid) by microorganisms: a review.

PubMed

Dhakal, Radhika; Bajpai, Vivek K; Baek, Kwang-Hyun

2012-10-01

GABA (γ-aminobutyric acid) is a four carbon non-protein amino acid that is widely distributed in plants, animals and microorganisms. As a metabolic product of plants and microorganisms produced by the decarboxylation of glutamic acid, GABA functions as an inhibitory neurotransmitter in the brain that directly affects the personality and the stress management. A wide range of traditional foods produced by microbial fermentation contain GABA, in which GABA is safe and eco-friendly, and also has the possibility of providing new health-benefited products enriched with GABA. Synthesis of GABA is catalyzed by glutamate decarboxylase, therefore, the optimal fermentation condition is mainly based on the biochemical properties of the enzyme. Major GABA producing microorganisms are lactic acid bacteria (LAB), which make food spoilage pathogens unable to grow and act as probiotics in the gastrointestinal tract. The major factors affecting the production of GABA by microbial fermentation are temperature, pH, fermentation time and different media additives, therefore, these factors are summarized to provide the most up-dated information for effective GABA synthesis. There has been a huge accumulation of knowledge on GABA application for human health accompanying with a demand on natural GABA supply. Only the GABA production by microorganisms can fulfill the demand with GABA-enriched health beneficial foods.

Gamma-Aminobutyric Acid Production Using Immobilized Glutamate Decarboxylase Followed by Downstream Processing with Cation Exchange Chromatography

PubMed Central

Lee, Seungwoon; Ahn, Jungoh; Kim, Yeon-Gu; Jung, Joon-Ki; Lee, Hongweon; Lee, Eun Gyo

2013-01-01

We have developed a gamma-aminobutyric acid (GABA) production technique using his-tag mediated immobilization of Escherichia coli-derived glutamate decarboxylase (GAD), an enzyme that catalyzes the conversion of glutamate to GABA. The GAD was obtained at 1.43 g/L from GAD-overexpressed E. coli fermentation and consisted of 59.7% monomer, 29.2% dimer and 2.3% tetramer with a 97.6% soluble form of the total GAD. The harvested GAD was immobilized to metal affinity gel with an immobilization yield of 92%. Based on an investigation of specific enzyme activity and reaction characteristics, glutamic acid (GA) was chosen over monosodium glutamate (MSG) as a substrate for immobilized GAD, resulting in conversion of 2.17 M GABA in a 1 L reactor within 100 min. The immobilized enzymes retained 58.1% of their initial activities after ten consecutive uses. By using cation exchange chromatography followed by enzymatic conversion, GABA was separated from the residual substrate and leached GAD. As a consequence, the glutamic acid was mostly removed with no detectable GAD, while 91.2% of GABA was yielded in the purification step. PMID:23322022

Widespread abnormality of the γ-aminobutyric acid-ergic system in Tourette syndrome

PubMed Central

Bagic, Anto; Simmons, Janine M.; Mari, Zoltan; Bonne, Omer; Xu, Ben; Kazuba, Diane; Herscovitch, Peter; Carson, Richard E.; Murphy, Dennis L.; Drevets, Wayne C.; Hallett, Mark

2012-01-01

Dysfunction of the γ-aminobutyric acid-ergic system in Tourette syndrome may conceivably underlie the symptoms of motor disinhibition presenting as tics and psychiatric manifestations, such as attention deficit hyperactivity disorder and obsessive–compulsive disorder. The purpose of this study was to identify a possible dysfunction of the γ-aminobutyric acid-ergic system in Tourette patients, especially involving the basal ganglia-thalamo-cortical circuits and the cerebellum. We studied 11 patients with Tourette syndrome and 11 healthy controls. Positron emission tomography procedure: after injection of 20 mCi of [11C]flumazenil, dynamic emission images of the brain were acquired. Structural magnetic resonance imaging scans were obtained to provide an anatomical framework for the positron emission tomography data analysis. Images of binding potential were created using the two-step version of the simplified reference tissue model. The binding potential images then were spatially normalized, smoothed and compared between groups using statistical parametric mapping. We found decreased binding of GABAA receptors in Tourette patients bilaterally in the ventral striatum, globus pallidus, thalamus, amygdala and right insula. In addition, the GABAA receptor binding was increased in the bilateral substantia nigra, left periaqueductal grey, right posterior cingulate cortex and bilateral cerebellum. These results are consistent with the longstanding hypothesis that circuits involving the basal ganglia and thalamus are disinhibited in Tourette syndrome patients. In addition, the abnormalities in GABAA receptor binding in the insula and cerebellum appear particularly noteworthy based upon recent evidence implicating these structures in the generation of tics. PMID:22577221

[Influence of exogenous gamma-aminobutyric acid (GABA) on GABA metabolism and amino acid contents in roots of melon seedling under hypoxia stress].

PubMed

Wang, Chun-Yan; Li, Jing-Rui; Xia, Qing-Ping; Wu, Xiao-Lei; Gao, Hong-Bo

2014-07-01

This paper investigated the influence of gamma-aminobutyric acid (GABA) on GABA metabolism and amino acid content under hypoxia stress by accurately controlling the level of dissolved oxygen in hydroponics, using the roots of melon 'Xiyu 1' seedlings as the test material. The results showed that compared with the control, the growth of roots was inhibited seriously under hypoxia stress. Meanwhile, the hypoxia-treated roots had significantly higher activities of glutamate decarboxylase (GAD), glutamate dehydrogenase (GDH), glutamate synthase (GOGAT), glutamine synthetase (GS), alanine aminotransferase (ALT), aspartate aminotransferase (AST) as well as the contents of GABA, pyruvic acid, alanine (Ala) and aspartic acid (Asp). But the contents of glutamic acid (Glu) and alpha-keto glutaric acid in roots under hypoxia stress was obviously lower than those of the control. Exogenous treatment with GABA alleviated the inhibition effect of hypoxia stress on root growth, which was accompanied by an increase in the contents of endogenous GABA, Glu, alpha-keto glutaric acid and Asp. Furthermore, under hypoxia stress, the activities of GAD, GDH, GOGAT, GS, ALT, AST as well as the contents of pyruvic acid and Ala significantly decreased in roots treated with GABA. However, adding GABA and viny-gamma-aminobutyric acid (VGB) reduced the alleviation effect of GABA on melon seedlings under hypoxia stress. The results suggested that absorption of GABA by roots could alleviate the injury of hypoxia stress to melon seedlings. This meant that GABA treatment allows the normal physiological metabolism under hypoxia by inhibiting the GAD activity through feedback and maintaining higher Glu content as well as the bal- ance of carbon and nitrogen.

γ-Aminobutyric acid (GABA) signalling in plants.

PubMed

Ramesh, Sunita A; Tyerman, Stephen D; Gilliham, Matthew; Xu, Bo

2017-05-01

The role of γ-aminobutyric acid (GABA) as a signal in animals has been documented for over 60 years. In contrast, evidence that GABA is a signal in plants has only emerged in the last 15 years, and it was not until last year that a mechanism by which this could occur was identified-a plant 'GABA receptor' that inhibits anion passage through the aluminium-activated malate transporter family of proteins (ALMTs). ALMTs are multigenic, expressed in different organs and present on different membranes. We propose GABA regulation of ALMT activity could function as a signal that modulates plant growth, development, and stress response. In this review, we compare and contrast the plant 'GABA receptor' with mammalian GABA A receptors in terms of their molecular identity, predicted topology, mode of action, and signalling roles. We also explore the implications of the discovery that GABA modulates anion flux in plants, its role in signal transduction for the regulation of plant physiology, and predict the possibility that there are other GABA interaction sites in the N termini of ALMT proteins through in silico evolutionary coupling analysis; we also explore the potential interactions between GABA and other signalling molecules.

Enrichment of Gamma-Aminobutyric Acid in Bean Sprouts: Exploring Biosynthesis of Plant Metabolite Using Common Household Reagents

ERIC Educational Resources Information Center

Rojanarata, Theerasak; Plianwong, Samarwadee; Opanasopit, Praneet; Ngawhirunpat, Tanasait

2018-01-01

The enrichment of plant foods with gamma-aminobutyric acid (GABA) is currently an interesting issue in the field of nutraceuticals and can be used as an experiment for upper-division undergraduate students. Here, an interdisciplinary hands-on experiment to produce GABA-enriched mung bean sprouts using common household reagents is described. Based…

G-protein-coupled receptors for neurotransmitter amino acids: C-terminal tails, crowded signalosomes.

PubMed Central

El Far, Oussama; Betz, Heinrich

2002-01-01

G-protein-coupled receptors (GPCRs) represent a superfamily of highly diverse integral membrane proteins that transduce external signals to different subcellular compartments, including nuclei, via trimeric G-proteins. By differential activation of diffusible G(alpha) and membrane-bound G(beta)gamma subunits, GPCRs might act on both cytoplasmic/intracellular and plasma-membrane-bound effector systems. The coupling efficiency and the plasma membrane localization of GPCRs are regulated by a variety of interacting proteins. In this review, we discuss recently disclosed protein interactions found with the cytoplasmic C-terminal tail regions of two types of presynaptic neurotransmitter receptors, the group III metabotropic glutamate receptors and the gamma-aminobutyric acid type-B receptors (GABA(B)Rs). Calmodulin binding to mGluR7 and other group III mGluRs may provide a Ca(2+)-dependent switch for unidirectional (G(alpha)) versus bidirectional (G(alpha) and G(beta)gamma) signalling to downstream effector proteins. In addition, clustering of mGluR7 by PICK1 (protein interacting with C-kinase 1), a polyspecific PDZ (PSD-95/Dlg1/ZO-1) domain containing synaptic organizer protein, sheds light on how higher-order receptor complexes with regulatory enzymes (or 'signalosomes') could be formed. The interaction of GABA(B)Rs with the adaptor protein 14-3-3 and the transcription factor ATF4 (activating transcription factor 4) suggests novel regulatory pathways for G-protein signalling, cytoskeletal reorganization and nuclear gene expression: processes that may all contribute to synaptic plasticity. PMID:12006104

Picrotoxin antagonism of γ aminobutyric acid inhibitory responses and synaptic inhibition in the rat substantia nigra

PubMed Central

Crossman, A. R.; Walker, R. J.; Woodruff, G. N.

1973-01-01

Neurones in the substantia nigra of the rat, anaesthetized with urethane, are inhibited both by electrical stimulation of the ipsilateral caudate nucleus and by iontophoretically applied γ-aminobutyric acid (GABA). Iontophoretically applied picrotoxin reversibly blocks both of these inhibitory responses. These results are consistent with the hypothesis that GABA is the transmitter released by the inhibitory striato-nigral pathway. PMID:4362811

Brain gamma-aminobutyric acid (GABA) abnormalities in bipolar disorder

PubMed Central

Brady, Roscoe O; McCarthy, Julie M; Prescot, Andrew P; Jensen, J Eric; Cooper, Alissa J; Cohen, Bruce M; Renshaw, Perry F; Ongür, Dost

2017-01-01

Objectives Gamma-aminobutyric acid (GABA) abnormalities have been implicated in bipolar disorder. However, due to discrepant studies measuring postmortem, cerebrospinal fluid, plasma, and in vivo brain levels of GABA, the nature of these abnormalities is unclear. Using proton magnetic resonance spectroscopy, we investigated tissue levels of GABA in the anterior cingulate cortex and parieto-occipital cortex of participants with bipolar disorder and healthy controls. Methods Fourteen stably medicated euthymic outpatients with bipolar disorder type I (mean age 32.6 years, eight male) and 14 healthy control participants (mean age 36.9 years, 10 male) completed a proton magnetic resonance spectroscopy scan at 4-Tesla after providing informed consent. We collected data from two 16.7-mL voxels using MEGAPRESS, and they were analyzed using LCModel. Results GABA/creatine ratios were elevated in bipolar disorder participants compared to healthy controls [F(1,21) = 4.4, p = 0.048] in the anterior cingulate cortex (25.1% elevation) and the parieto-occipital cortex (14.6% elevation). Bipolar disorder participants not taking GABA-modulating medications demonstrated greater GABA/creatine elevations than patients taking GABA-modulating medications. Conclusions We found higher GABA/creatine levels in euthymic bipolar disorder outpatients compared to healthy controls, and the extent of this elevation may be affected by the use of GABA-modulating medications. Our findings suggest that elevated brain GABA levels in bipolar disorder may be associated with GABAergic dysfunction and that GABA-modulating medications reduce GABA levels in this condition. PMID:23634979

Gaussian and linear deconvolution of LC-MS/MS chromatograms of the eight aminobutyric acid isomers

PubMed Central

Vemula, Harika; Kitase, Yukiko; Ayon, Navid J.; Bonewald, Lynda; Gutheil, William G.

2016-01-01

Isomeric molecules present a challenge for analytical resolution and quantification, even with MS-based detection. The eight-aminobutyric acid (ABA) isomers are of interest for their various biological activities, particularly γ-aminobutyric acid (GABA) and the d- and l-isomers of β-aminoisobutyric acid (β-AIBA; BAIBA). This study aimed to investigate LC-MS/MS-based resolution of these ABA isomers as their Marfey's (Mar) reagent derivatives. HPLC was able to separate three Mar-ABA isomers l-β-ABA (l-BABA), and l- and d-α-ABA (AABA) completely, with three isomers (GABA, and d/l-BAIBA) in one chromatographic cluster, and two isomers (α-AIBA (AAIBA) and d-BABA) in a second cluster. Partially separated cluster components were deconvoluted using Gaussian peak fitting except for GABA and d-BAIBA. MS/MS detection of Marfey's derivatized ABA isomers provided six MS/MS fragments, with substantially different intensity profiles between structural isomers. This allowed linear deconvolution of ABA isomer peaks. Combining HPLC separation with linear and Gaussian deconvolution allowed resolution of all eight ABA isomers. Application to human serum found a substantial level of l-AABA (13 μM), an intermediate level of l-BAIBA (0.8 μM), and low but detectable levels (<0.2 μM) of GABA, l-BABA, AAIBA, d-BAIBA, and d-AABA. This approach should be useful for LC-MS/MS deconvolution of other challenging groups of isomeric molecules. PMID:27771391

Separation and purification of γ-aminobutyric acid from fermentation broth by flocculation and chromatographic methodologies.

PubMed

Gao, Qiang; Duan, Qiang; Wang, Depei; Zhang, Yunze; Zheng, Chunyang

2013-02-27

To date, the multifunctional γ-aminobutyric acid (GABA) is mainly produced by microbial fermentation in industry. The purpose of this study was to find an effective method for separation and purification of 31.2 g/L initial GABA from the fermentation broth of Enterococcus raffinosus TCCC11660. To remove the impurities from fermentation broth, flocculation pretreatment using chitosan and sodium alginate was first implemented to facilitate subsequent filtration. Ultrafiltration followed two discontinuous diafiltration steps to effectively remove proteins and macromolecular pigments, and the resulting permeate was further decolored by DA201-CII resin at a high decoloration ratio and GABA recovery. Subsequently, ion exchange chromatography (IEC) with Amberlite 200C resin and gradient elution were applied for GABA separation from glutamate and arginine. Finally, GABA crystals of 99.1% purity were prepared via warm ethanol precipitation twice. Overall, our results reveal that the successive process including flocculation, filtration, ultrafiltration, decoloration, IEC, and crystallization is promising for scale-up GABA extraction from fermentation broth.

Beta-aminobutyric acid priming of plant defense: the role of ABA and other hormones.

PubMed

Baccelli, Ivan; Mauch-Mani, Brigitte

2016-08-01

Plants are exposed to recurring biotic and abiotic stresses that can, in extreme situations, lead to substantial yield losses. With the changing environment, the stress pressure is likely to increase and sustainable measures to alleviate the effect on our crops are sought. Priming plants for better stress resistance is one of the sustainable possibilities to reach this goal. Here, we report on the effects of beta-aminobutyric acid, a priming agent with an exceptionally wide range of action and describe its way of preparing plants to defend themselves against various attacks, among others through the modulation of their hormonal defense signaling, and highlight the special role of abscisic acid in this process.

Production of gaba (γ – Aminobutyric acid) by microorganisms: a review

PubMed Central

Dhakal, Radhika; Bajpai, Vivek K.; Baek, Kwang-Hyun

2012-01-01

GABA (γ-aminobutyric acid) is a four carbon non-protein amino acid that is widely distributed in plants, animals and microorganisms. As a metabolic product of plants and microorganisms produced by the decarboxylation of glutamic acid, GABA functions as an inhibitory neurotransmitter in the brain that directly affects the personality and the stress management. A wide range of traditional foods produced by microbial fermentation contain GABA, in which GABA is safe and eco-friendly, and also has the possibility of providing new health-benefited products enriched with GABA. Synthesis of GABA is catalyzed by glutamate decarboxylase, therefore, the optimal fermentation condition is mainly based on the biochemical properties of the enzyme. Major GABA producing microorganisms are lactic acid bacteria (LAB), which make food spoilage pathogens unable to grow and act as probiotics in the gastrointestinal tract. The major factors affecting the production of GABA by microbial fermentation are temperature, pH, fermentation time and different media additives, therefore, these factors are summarized to provide the most up-dated information for effective GABA synthesis. There has been a huge accumulation of knowledge on GABA application for human health accompanying with a demand on natural GABA supply. Only the GABA production by microorganisms can fulfill the demand with GABA-enriched health beneficial foods. PMID:24031948

Cortical Gamma-Aminobutyric Acid and Glutamate in Posttraumatic Stress Disorder and Their Relationships to Self-Reported Sleep Quality

PubMed Central

Meyerhoff, Dieter J.; Mon, Anderson; Metzler, Thomas; Neylan, Thomas C.

2014-01-01

Study Objectives: To test if posttraumatic stress disorder (PTSD) is associated with low brain gamma-aminobutyric acid (GABA) levels and if reduced GABA is mediated by poor sleep quality. Design: Laboratory study using in vivo proton magnetic resonance spectroscopy (1H MRS) and behavioral testing. Setting: VA Medical Center Research Service, Psychiatry and Radiology. Patients or Participants: Twenty-seven patients with PTSD (PTSD+) and 18 trauma-exposed controls without PTSD (PTSD−), recruited from United States Army reservists, Army National Guard, and mental health clinics. Interventions: None. Measurements and Results: 1H MRS at 4 Tesla yielded spectra from three cortical brain regions. In parieto-occipital and temporal cortices, PTSD+ had lower GABA concentrations than PTSD−. As expected, PTSD+ had higher depressive and anxiety symptom scores and a higher Insomnia Severity Index (ISI) score. Higher ISI correlated with lower GABA and higher glutamate levels in parieto-occipital cortex and tended to correlate with lower GABA in the anterior cingulate. The relationship between parieto-occipital GABA and PTSD diagnosis was fully mediated through insomnia severity. Lower N-acetylaspartate and glutamate concentrations in the anterior cingulate cortex correlated with higher arousal scores, whereas depressive and anxiety symptoms did generally not influence metabolite concentrations. Conclusions: Low brain gamma-aminobutyric acid (GABA) concentration in posttraumatic stress disorder (PTSD) is consistent with most findings in panic and social anxiety disorders. Low GABA associated with poor sleep quality is consistent with the hyperarousal theory of both primary insomnia and PTSD. Our data demonstrate that poor sleep quality mediates low parieto-occipital GABA in PTSD. The findings have implications for PTSD treatment approaches. Citation: Meyerhoff DJ, Mon A, Metzler T, Neylan TC. Cortical gamma-aminobutyric acid and glutamate in posttraumatic stress disorder and

A GC-ECD method for estimation of free and bound amino acids, gamma-aminobutyric acid, salicylic acid, and acetyl salicylic acid from Solanum lycopersicum (L.).

PubMed

Meher, Hari Charan; Gajbhiye, Vijay T; Singh, Ghanendra

2011-01-01

A gas chromatograph with electron capture detection method for estimation of selected metabolites--amino acids (free and bound), gamma-aminobutyric acid (GABA), salicylic acid (SA), and acetyl salicylic acid (ASA) from tomato--is reported. The method is based on nitrophenylation of the metabolites by 1-fluoro-2, 4-dinitrobenzene under aqueous alkaline conditions to form dinitophenyl derivatives. The derivatives were stable under the operating conditions of GC. Analysis of bound amino acids comprised perchloric acid precipitation of protein, alkylation (carboxymethylation) with iodoacetic acid, vapor-phase hydrolysis, and derivatization with 1-fluoro-2,4-dinitrobenzene in that order. The metabolites were resolved in 35 min, using a temperature-programmed run. The method is rapid, sensitive, and precise. It easily measured the typical amino acids (aspartate, asparagine, glutamate, glutamine, alanine, leucine, lysine, and phenylalanine) used for identification and quantification of a protein, resolved amino acids of the same mass (leucine and isoleucine), satisfactorily measured sulfur amino acid (methionine, cystine, and cysteine), and quantified GABA, SA, and ASA, as well. The developed method was validated for specificity, linearity, and precision. It has been applied and recommended for estimation of 25 metabolites from Solanum lycopersicum (L.).

The Gamma-Aminobutyric Acid B Receptor in Depression and Reward.

PubMed

Jacobson, Laura H; Vlachou, Styliani; Slattery, David A; Li, Xia; Cryan, John F

2018-06-01

The metabotropic gamma-aminobutyric acid B (GABA B ) receptor was the first described obligate G protein-coupled receptor heterodimer and continues to set the stage for discoveries in G protein-coupled receptor signaling complexity. In this review, dedicated to the life and work of Athina Markou, we explore the role of GABA B receptors in depression, reward, and the convergence of these domains in anhedonia, a shared symptom of major depressive disorder and withdrawal from drugs of abuse. GABA B receptor expression and function are enhanced by antidepressants and reduced in animal models of depression. Generally, GABA B receptor antagonists are antidepressant-like and agonists are pro-depressive. Exceptions to this rule likely reflect the differential influence of GABA B1 isoforms in depression-related behavior and neurobiology, including the anhedonic effects of social stress. A wealth of data implicate GABA B receptors in the rewarding effects of drugs of abuse. We focus on nicotine as an example. GABA B receptor activation attenuates, and deactivation enhances, nicotine reward and associated neurobiological changes. In nicotine withdrawal, however, GABA B receptor agonists, antagonists, and positive allosteric modulators enhance anhedonia, perhaps owing to differential effects of GABA B1 isoforms on the dopaminergic system. Nicotine cue-induced reinstatement is more reliably attenuated by GABA B receptor activation. Separation of desirable and undesirable side effects of agonists is achievable with positive allosteric modulators, which are poised to enter clinical studies for drug abuse. GABA B1 isoforms are key to understanding the neurobiology of anhedonia, whereas allosteric modulators may offer a mechanism for targeting specific brain regions and processes associated with reward and depression. Copyright © 2018 Society of Biological Psychiatry. All rights reserved.

Gama-aminobutyric acid accumulation in Elsholtzia splendens in response to copper toxicity*

PubMed Central

Yang, Xiao-e; Peng, Hong-yun; Tian, Sheng-ke

2005-01-01

A solution with different Cu supply levels was cultured to investigate gama-aminobutyric acid (GABA) accumulation in Elsholtzia splendens, a native Chinese Cu-tolerant and accumulating plant species. Increasing Cu from 0.25 to 500 μmol/L significantly enhanced levels of GABA and histidine (His), but considerably decreased levels of aspartate (Asp) and glutamate (Glu) in the leaves. The leaf Asp level negatively correlated with leaf Cu level, while leaf GABA level positively correlated with leaf Cu level. The leaf Glu level negatively correlated with leaf GABA level in Elsholtzia splendens. The depletion of leaf Glu may be related to the enhanced synthesis of leaf GABA under Cu stress. PMID:15633244

Evaluation of improved γ-aminobutyric acid production in yogurt using Lactobacillus plantarum NDC75017.

PubMed

Shan, Y; Man, C X; Han, X; Li, L; Guo, Y; Deng, Y; Li, T; Zhang, L W; Jiang, Y J

2015-04-01

Most γ-aminobutyric acid (GABA)-producing microorganisms are lactic acid bacteria (LAB), but the yield of GABA is limited in most of these GABA-producing strains. In this study, the production of GABA was carried out by using Lactobacillus plantarum NDC75017, a strain screened from traditional fermented dairy products in China. Concentrations of substrate (l-monosodium glutamate, L-MSG) and coenzyme (pyridoxal-5-phosphate, PLP) of glutamate decarboxylase (GAD) and culture temperature were investigated to evaluate their effects on GABA yield of Lb. plantarum NDC75017. The results indicated that GABA production was related to GAD activity and biomass of Lb. plantarum NDC75017. Response surface methodology was used to optimize conditions of GABA production. The optimal factors for GABA production were L-MSG at 80 mM, PLP at 18 μM, and a culture temperature of 36 °C. Under these conditions, production of GABA was maximized at 314.56 mg/100 g. Addition of Lb. plantarum NDC75017 to a commercial starter culture led to higher GABA production in fermented yogurt. Flavor and texture of the prepared yogurt and the control yogurt did not differ significantly. Thus, Lb. plantarum NDC75017 has good potential for manufacture of GABA-enriched fermented milk products. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Acidification and γ-aminobutyric acid independently alter kairomone-induced behaviour

PubMed Central

Cohen, Jonathan H.

2016-01-01

Exposure to high pCO2 or low pH alters sensation and behaviour in many marine animals. We show that crab larvae lose their ability to detect and/or process predator kairomones after exposure to low pH over a time scale relevant to diel pH cycles in coastal environments. Previous work suggests that acidification affects sensation and behaviour through altered neural function, specifically the action of γ-aminobutyric acid (GABA), because a GABA antagonist, gabazine, restores the original behaviour. Here, however, gabazine resulted in a loss of kairomone detection/processing, regardless of pH. Our results also suggest that GABAergic signalling is necessary for kairomone identification in these larvae. Hence, the mechanism for the observed pH effect varies from the original GABA hypothesis. Furthermore, we suggest that this pH effect is adaptive under diel-cycling pH. PMID:27703697

[The effect of niflumic acid on gamma aminobutyric acid activated current in DRG neurons].

PubMed

Li, Li; Li, Jing; Ma, Ke-Tao; Cheng, Hong-Ju; Zhao, Lei; Wang, Yang; Si, Jun-Qiang

2013-01-01

To explore the modulatory effect of niflumic acid (NFA) on gamma aminobutyric acid (GABA)-activated currents of dorsal root ganglion (DRG) neurons in rat. The whole-cell patch-clamp technique was used to record the NFA- and GABA-activated currents in neurons freshly dissociated from rat DRG neurons. Application of NFA(0.1 - 100 micromol/L) could induce concentration-dependent outward currents in some cells (21/48,43.75%), and GABA (0.1 - 100 micromol/L) could induce concentration-dependent inward currents in some cells(150/159,94.32%). NFA-(100 micromol/L) and GABA-(100 micromol/L) activated currents were (0.27 +/- 0.06) nA (n = 12) and (1.29 +/- 0.72) nA (n = 53) respectively. However, pre-application of NFA (0.1 - 100 micromol/L) could inhibit the GABA-activated inward current which was identified to be GABAA receptor-mediated current. The inhibitory effects of NFA were concentration-dependent. NFA could not alter the EC50 (about 30 micromol/L) and inverse potential (about -10 mV) of GABA-activated current (P > 0.05). Pre-application of NFA exerts a more strong inhibitory effect on the peak value of GABA-activated current.

Opiate-induced motor stimulation is regulated by gamma-aminobutyric acid type B receptors found in the ventral tegmental area in mice.

PubMed

Leite-Morris, Kimberly A; Fukudome, Eugene Y; Kaplan, Gary B

2002-01-14

Recent studies suggest that gamma-aminobutyric acid type B (GABA(B)) receptors located on dopaminergic cells in the ventral tegmental area (VTA) regulate mesolimbic dopaminergic (A10) activity. In the current study, we identified GABA(B) receptor subtypes in the area of the VTA and examined their role in modulating acute opiate actions. We studied the effects of intra-VTA infusions of the selective GABA(B) agonist baclofen on morphine-induced locomotor stimulation and A10 neuronal activation. Drug treatments were followed by ambulatory activity monitoring for 180 min. Intra-VTA baclofen treatment produced a 70% inhibition of morphine-stimulated locomotor activity. Furthermore, functional activation of A10 neurons was assessed by immunohistochemical staining of c-Fos in the nucleus accumbens (NAc), where A10 neurons terminate. We found that morphine treatment increased the levels of Fos-positive nuclei in the NAc, while intra-VTA baclofen treatment reversed morphine's effects. Finally, GABA(B) receptor subtypes and isoforms were identified in the ventromedial mesencephalon using immunoblotting. We demonstrated the presence of GABA(B)R1a (130 kDa), GABA(B)R1b (100 kDa), and GABA(B)R2 (120 kDa) receptor subtypes in this region. These results suggest that GABA(B) receptor isoforms are found in the VTA and their activation results in the blockade of behavioral effects of opiates via inhibition of dopaminergic neurotransmission.

Conformational preferences of γ-aminobutyric acid in the gas phase and in water

NASA Astrophysics Data System (ADS)

Song, Il Keun; Kang, Young Kee

2012-09-01

The conformational study of γ-aminobutyric acid (GABA) has been carried out at the M06-2X/cc-pVTZ level of theory in the gas phase and the SMD M06-2X/cc-pVTZ level of theory in water. In the gas phase, the folded conformation gG1 with gauche- and gauche+ conformations for the Cβsbnd Cα and Cγsbnd Cβ bonds, respectively, is found to be lowest in energy and enthalpy, which can be ascribed to the favored hyperconjugative n → π* interaction between the lone electron pair of the amine nitrogen atom and the Cdbnd O bond of the carboxylic group and the favored antiparallel dipole-dipole interaction between the Nsbnd H bond and the Cdbnd O bond. In addition, the intramolecular hydrogen bonds between the carboxylic group and the amine Nsbnd H group have contributed to stabilize some low-energy conformers. However, the most preferred conformation is found to be tG1 and more stable by 0.4 kcal/mol in ΔG than the conformer gG1, in which the favored entropic term due to the conformational flexibility and the other favored n → σ*, σ → σ*, and π → σ* interactions seem to play a role. The conformational preferences of the neutral GABA calculated by ΔG's are reasonably consistent with the populations deduced from FT microwave spectroscopy in supersonic jets combined with laser ablation. In water, the two folded conformers Gg and gG of the zwitterionic GABA are dominantly populated, each of which has the population of 47%, and the hydrogen bond between the ammonium Nsbnd H group and the lone electron pair of the Csbnd O- group seems to be crucial in stabilizing these conformers. Our calculated result that the folded conformers preferentially exist in water is consistent with the 1H NMR experiments in D2O.

Optimization of γ-aminobutyric acid production by Lactobacillus plantarum Taj-Apis362 from honeybees.

PubMed

Tajabadi, Naser; Ebrahimpour, Afshin; Baradaran, Ali; Rahim, Raha Abdul; Mahyudin, Nor Ainy; Manap, Mohd Yazid Abdul; Bakar, Fatimah Abu; Saari, Nazamid

2015-04-15

Dominant strains of lactic acid bacteria (LAB) isolated from honey bees were evaluated for their γ-aminobutyric acid (GABA)-producing ability. Out of 24 strains, strain Taj-Apis362 showed the highest GABA-producing ability (1.76 mM) in MRS broth containing 50 mM initial glutamic acid cultured for 60 h. Effects of fermentation parameters, including initial glutamic acid level, culture temperature, initial pH and incubation time on GABA production were investigated via a single parameter optimization strategy. The optimal fermentation condition for GABA production was modeled using response surface methodology (RSM). The results showed that the culture temperature was the most significant factor for GABA production. The optimum conditions for maximum GABA production by Lactobacillus plantarum Taj-Apis362 were an initial glutamic acid concentration of 497.97 mM, culture temperature of 36 °C, initial pH of 5.31 and incubation time of 60 h, which produced 7.15 mM of GABA. The value is comparable with the predicted value of 7.21 mM.

Production of γ-aminobutyric acid by microorganisms from different food sources.

PubMed

Hudec, Jozef; Kobida, Ľubomír; Čanigová, Margita; Lacko-Bartošová, Magdaléna; Ložek, Otto; Chlebo, Peter; Mrázová, Jana; Ducsay, Ladislav; Bystrická, Judita

2015-04-01

γ-Aminobutyric acid (GABA) is a potentially bioactive component of foods and pharmaceuticals. The aim of this study was screen lactic acid bacteria belonging to the Czech Collection of Microorganisms, and microorganisms (yeast and bacteria) from 10 different food sources for GABA production by fermentation in broth or plant and animal products. Under an aerobic atmosphere, very low selectivity of GABA production (from 0.8% to 1.3%) was obtained using yeast and filamentous fungi, while higher selectivity (from 6.5% to 21.0%) was obtained with bacteria. The use of anaerobic conditions, combined with the addition of coenzyme (pyridoxal-5-phosphate) and salts (CaCl2 , NaCl), led to the detection of a low concentration of GABA precursor. Simultaneously, using an optimal temperature of 33 °C, a pH of 6.5 and bacteria from banana (Pseudomonadaceae and Enterobacteriaceae families), surprisingly, a high selectivity of GABA was obtained. A positive impact of fenugreek sprouts on the proteolytic process and GABA production from plant material as a source of GABA precursor was identified. Lactic acid bacteria for the production of new plant and animal GABA-rich products from different natural sources containing GABA precursor can be used. © 2014 Society of Chemical Industry.

Genetic manipulation of the γ-aminobutyric acid (GABA) shunt in rice: overexpression of truncated glutamate decarboxylase (GAD2) and knockdown of γ-aminobutyric acid transaminase (GABA-T) lead to sustained and high levels of GABA accumulation in rice kernels.

PubMed

Shimajiri, Yasuka; Oonishi, Takayuki; Ozaki, Kae; Kainou, Kumiko; Akama, Kazuhito

2013-06-01

Gamma-aminobutyric acid (GABA) is a non-protein amino acid commonly present in all organisms. Because cellular levels of GABA in plants are mainly regulated by synthesis (glutamate decarboxylase, GAD) and catabolism (GABA-transaminase, GABA-T), we attempted seed-specific manipulation of the GABA shunt to achieve stable GABA accumulation in rice. A truncated GAD2 sequence, one of five GAD genes, controlled by the glutelin (GluB-1) or rice embryo globulin promoters (REG) and GABA-T-based trigger sequences in RNA interference (RNAi) cassettes controlled by one of these promoters as well, was introduced into rice (cv. Koshihikari) to establish stable transgenic lines under herbicide selection using pyriminobac. T₁ and T₂ generations of rice lines displayed high GABA concentrations (2-100 mg/100 g grain). In analyses of two selected lines from the T₃ generation, there was a strong correlation between GABA level and the expression of truncated GAD2, whereas the inhibitory effect of GABA-T expression was relatively weak. In these two lines both with two T-DNA copies, their starch, amylose, and protein levels were slightly lower than non-transformed cv. Koshihikari. Free amino acid analysis of mature kernels of these lines demonstrated elevated levels of GABA (75-350 mg/100 g polished rice) and also high levels of several amino acids, such as Ala, Ser, and Val. Because these lines of seeds could sustain their GABA content after harvest (up to 6 months), the strategy in this study could lead to the accumulation GABA and for these to be sustained in the edible parts. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Probing the steric requirements of the γ-aminobutyric acid aminotransferase active site with fluorinated analogues of vigabatrin

PubMed Central

Juncosa, Jose I.; Groves, Andrew P.; Xia, Guoyao; Silverman, Richard B.

2012-01-01

We have synthesized three analogues of 4-amino-5-fluorohexanoic acids as potential inactivators of γ-aminobutyric acid aminotransferase (GABA-AT), which were designed to combine the potency of their shorter chain analogue, 4-amino-5-fluoropentanoic acid (AFPA), with the greater enzyme selectivity of the antiepileptic vigabatrin (Sabril®). Unexpectedly, these compounds failed to inactivate or inhibit the enzyme, even at high concentrations. On the basis of molecular modeling studies, we propose that the GABA-AT active site has an accessory binding pocket that accommodates the vinyl group of vigabatrin and the fluoromethyl group of AFPA, but is too narrow to support the extra width of one distal methyl group in the synthesized analogues. PMID:23306054

Subchronic toxicity evaluation of γ-aminobutyric acid (GABA) in rats.

PubMed

Takeshima, Kazuhito; Yamatsu, Atsushi; Yamashita, Yusuke; Watabe, Kazuya; Horie, Noriko; Masuda, Kazuyuki; Kim, Mujo

2014-06-01

γ-Aminobutyric acid (GABA) is an amino acid compound contained in vegetables such as tomatoes and also widely distributed in mammals. GABA acts as an inhibitory neurotransmitter and promotes parasympathetic activity to provide several beneficial effects, for instance, relaxation, anti-stress, and insomnia. GABA, produced via a fermentation process, has been available as a functional food ingredient. As part of a program to assess its safety, GABA was administered by oral gavage at doses of 500, 1250, and 2500mg/kg body weight to groups of 10 male and 10 female Sprague-Dawley rats for 13weeks. Treatment was not associated with the test substance-related mortality and appeared to be well tolerated. There were no toxicologically and statistically significant changes in urinalysis, hematology, clinical chemistry parameters, and in necropsy findings. A few statistically significant changes in food consumption and body weights were noted in the male groups while any significant changes were not noted in female groups. There was no effect of treatment on organ weights or on the results of the histopathological examinations. The results of toxicity evaluation support the safety use of GABA and the potential use as a functional food ingredient. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gamma-aminobutyric acid aggravates nephrotoxicity induced by cisplatin in female rats.

PubMed

Peysepar, Elham; Soltani, Nepton; Nematbakhsh, Mehdi; Eshraghi-Jazi, Fatemeh; Talebi, Ardeshir

2016-01-01

Cisplatin (CP) is a major antineoplastic drug for treatment of solid tumors. CP-induced nephrotoxicity may be gender-related. This is while gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in the central nervous system that has renoprotective impacts on acute renal injury. This study was designed to investigate the protective role of GABA against CP-induced nephrotoxicity in male and female rats. Sixty Wistar male and female rats were used in eight experimental groups. Both genders received GABA (50 μg/kg/day; i. p.) for 14 days and CP (2.5 mg/kg/day; i. p.) was added from day 8 to the end of the study, and they were compared with the control groups. At the end of the study, all animals were sacrificed and the serum levels of blood urea nitrogen (BUN), creatinine (Cr), nitrite, malondialdehyde (MDA), and magnesium (Mg) were measured. The kidney tissue damage was also determined via staining. CP significantly increased the serum levels of Cr and BUN, kidney weight, and kidney tissue damage score in both genders (P<0.05). GABA did not attenuate these markers in males; even these biomarkers were intensified in females. Serum level of Mg, and testis and uterus weights did not alter in the groups. However, the groups were significantly different in terms of nitrite and MDA levels. It seems that GABA did not improve nephrotoxicity induced by CP-treated rats, and it exacerbated renal damage in female rats.

ELEVATED GAMMA-AMINOBUTYRIC ACID LEVELS IN CHRONIC SCHIZOPHRENIA

PubMed Central

Öngür, Dost; Prescot, Andrew P.; McCarthy, Julie; Cohen, Bruce M.; Renshaw, Perry F.

2010-01-01

Background Despite widely-replicated abnormalities of gamma-aminobutyric acid (GABA) neurons in schizophrenia postmortem, few studies have measured tissue GABA levels in vivo. We used proton magnetic resonance spectroscopy to measure tissue GABA levels in participants with schizophrenia and healthy controls in the anterior cingulate cortex (ACC) and parieto-occipital cortex (POC). Methods 21 schizophrenia participants effectively treated on a stable medication regimen (mean age 39.0, 14 male) and 19 healthy controls (mean age 36.3, 12 male) underwent a proton magnetic resonance spectroscopy scan using GABA-selective editing at 4 Tesla after providing informed consent. Data were collected from two 16.7cc voxels and analyzed using LCModel. Results We found elevations in GABA/Cr in the schizophrenia group compared with controls (F(1,65)=4.149, p=0.046) in both brain areas (15.5% elevation in ACC, 11.9% in POC). We also found a positive correlation between GABA/Cr and Glu/Cr which was not accounted for by %GM or brain region. Conclusions We found elevated GABA/Cr in participants with chronically treated schizophrenia. Postmortem studies report evidence for dysfunctional GABAergic neurotransmission in schizophrenia. Elevated GABA levels, whether primary to illness or compensatory to another process, may be associated with dysfunctional GABAergic neurotransmission in chronic schizophrenia. PMID:20598290

Biotechnological advances and perspectives of gamma-aminobutyric acid production.

PubMed

Xu, Ning; Wei, Liang; Liu, Jun

2017-03-01

Gamma-aminobutyric acid (GABA) is a four-carbon non-protein amino acid that is widely distributed among various organisms. Since GABA has several well-known physiological functions, such as mediating neurotransmission and hypotensive activity, as well as having tranquilizer effects, it is commonly used as a bioactive compound in the food, pharmaceutical and feed industries. The major pathway of GABA biosynthesis is the irreversible decarboxylation of L-glutamate catalyzed by glutamate decarboxylase (GAD), which develops a safe, sustainable and environmentally friendly alternative in comparison with traditional chemical synthesis methods. To date, several microorganisms have been successfully engineered for high-level GABA biosynthesis by overexpressing exogenous GADs. However, the activity of almost all reported microbial GADs sharply decreases at physiological near-neutral pH, which in turn provokes negative effects on the application of these GADs in the recombinant strains for GABA production. Therefore, ongoing efforts in the molecular evolution of GADs, in combination with high-throughput screening and metabolic engineering of particular producer strains, offer fascinating new prospects for effective, environmentally friendly and economically viable GABA biosynthesis. In this review, we briefly introduce the applications in which GABA is used, and summarize the most important methods associated with GABA production. The major achievements and present challenges in the biotechnological synthesis of GABA, focusing on screening and enzyme engineering of GADs, as well as metabolic engineering strategy for one-step GABA biosynthesis, will be extensively discussed.

High γ-aminobutyric acid production from lactic acid bacteria: Emphasis on Lactobacillus brevis as a functional dairy starter.

PubMed

Wu, Qinglong; Shah, Nagendra P

2017-11-22

γ-Aminobutyric acid (GABA) and GABA-rich foods have shown anti-hypertensive and anti-depressant activities as the major functions in humans and animals. Hence, high GABA-producing lactic acid bacteria (LAB) could be used as functional starters for manufacturing novel fermented dairy foods. Glutamic acid decarboxylases (GADs) from LAB are highly conserved at the species level based on the phylogenetic tree of GADs from LAB. Moreover, two functionally distinct GADs and one intact gad operon were observed in all the completely sequenced Lactobacillus brevis strains suggesting its common capability to synthesize GABA. Difficulties and strategies for the manufacture of GABA-rich fermented dairy foods have been discussed and proposed, respectively. In addition, a genetic survey on the sequenced LAB strains demonstrated the absence of cell envelope proteinases in the majority of LAB including Lb. brevis, which diminishes their cell viabilities in milk environments due to their non-proteolytic nature. Thus, several strategies have been proposed to overcome the non-proteolytic nature of Lb. brevis in order to produce GABA-rich dairy foods.

Gamma-aminobutyric acid depletion affects stomata closure and drought tolerance of Arabidopsis thaliana.

PubMed

Mekonnen, Dereje Worku; Flügge, Ulf-Ingo; Ludewig, Frank

2016-04-01

A rapid accumulation of γ-aminobutyric acid (GABA) during biotic and abiotic stresses is well documented. However, the specificity of the response and the primary role of GABA under such stress conditions are hardly understood. To address these questions, we investigated the response of the GABA-depleted gad1/2 mutant to drought stress. GABA is primarily synthesized from the decarboxylation of glutamate by glutamate decarboxylase (GAD) which exists in five copies in the genome of Arabidopsis thaliana. However, only GAD1 and GAD2 are abundantly expressed, and knockout of these two copies dramatically reduced the GABA content. Phenotypic analysis revealed a reduced shoot growth of the gad1/2 mutant. Furthermore, the gad1/2 mutant was wilted earlier than the wild type following a prolonged drought stress treatment. The early-wilting phenotype was due to an increase in stomata aperture and a defect in stomata closure. The increase in stomata aperture contributed to higher stomatal conductance. The drought oversensitive phenotype of the gad1/2 mutant was reversed by functional complementation that increases GABA level in leaves. The functionally complemented gad1/2 x pop2 triple mutant contained more GABA than the wild type. Our findings suggest that GABA accumulation during drought is a stress-specific response and its accumulation induces the regulation of stomatal opening thereby prevents loss of water. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Elevated gamma-aminobutyric acid levels in chronic schizophrenia.

PubMed

Ongür, Dost; Prescot, Andrew P; McCarthy, Julie; Cohen, Bruce M; Renshaw, Perry F

2010-10-01

Despite widely replicated abnormalities of gamma-aminobutyric acid (GABA) neurons in schizophrenia postmortem, few studies have measured tissue GABA levels in vivo. We used proton magnetic resonance spectroscopy to measure tissue GABA levels in participants with schizophrenia and healthy control subjects in the anterior cingulate cortex and parieto-occipital cortex. Twenty-one schizophrenia participants effectively treated on a stable medication regimen (mean age 39.0, 14 male) and 19 healthy control subjects (mean age 36.3, 12 male) underwent a proton magnetic resonance spectroscopy scan using GABA-selective editing at 4 Tesla after providing informed consent. Data were collected from two 16.7-mL voxels and analyzed using LCModel. We found elevations in GABA/creatine in the schizophrenia group compared with control subjects [F(1,65) = 4.149, p = .046] in both brain areas (15.5% elevation in anterior cingulate cortex, 11.9% in parieto-occipital cortex). We also found a positive correlation between GABA/creatine and glutamate/creatine, which was not accounted for by % GM or brain region. We found elevated GABA/creatinine in participants with chronically treated schizophrenia. Postmortem studies report evidence for dysfunctional GABAergic neurotransmission in schizophrenia. Elevated GABA levels, whether primary to illness or compensatory to another process, may be associated with dysfunctional GABAergic neurotransmission in chronic schizophrenia. Copyright © 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Metabolic pathways regulated by abscisic acid, salicylic acid and γ-aminobutyric acid in association with improved drought tolerance in creeping bentgrass (Agrostis stolonifera).

PubMed

Li, Zhou; Yu, Jingjin; Peng, Yan; Huang, Bingru

2017-01-01

Abscisic acid (ABA), salicylic acid (SA) and γ-aminobutyric acid (GABA) are known to play roles in regulating plant stress responses. This study was conducted to determine metabolites and associated pathways regulated by ABA, SA and GABA that could contribute to drought tolerance in creeping bentgrass (Agrostis stolonifera). Plants were foliar sprayed with ABA (5 μM), GABA (0.5 mM) and SA (10 μM) or water (untreated control) prior to 25 days drought stress in controlled growth chambers. Application of ABA, GABA or SA had similar positive effects on alleviating drought damages, as manifested by the maintenance of lower electrolyte leakage and greater relative water content in leaves of treated plants relative to the untreated control. Metabolic profiling showed that ABA, GABA and SA induced differential metabolic changes under drought stress. ABA mainly promoted the accumulation of organic acids associated with tricarboxylic acid cycle (aconitic acid, succinic acid, lactic acid and malic acid). SA strongly stimulated the accumulation of amino acids (proline, serine, threonine and alanine) and carbohydrates (glucose, mannose, fructose and cellobiose). GABA enhanced the accumulation of amino acids (GABA, glycine, valine, proline, 5-oxoproline, serine, threonine, aspartic acid and glutamic acid) and organic acids (malic acid, lactic acid, gluconic acid, malonic acid and ribonic acid). The enhanced drought tolerance could be mainly due to the enhanced respiration metabolism by ABA, amino acids and carbohydrates involved in osmotic adjustment (OA) and energy metabolism by SA, and amino acid metabolism related to OA and stress-defense secondary metabolism by GABA. © 2016 Scandinavian Plant Physiology Society.

Calming effect of orally administered γ-aminobutyric acid in Shih Tzu dogs.

PubMed

Uetake, Katsuji; Okumoto, Ayano; Tani, Noriko; Goto, Akihiro; Tanaka, Toshio

2012-12-01

The calming effects of γ-aminobutyric acid (GABA) by oral administration were investigated in four adult Shih Tzu dogs. Three dosage levels (1, 2 and 4 mg/kg body weight) and non-administration were tested by an increase and decrease method. Changes in activity (for 1.5 h) and urinary cortisol levels (pre-administration, 3 and 7 h later) of dogs were monitored after administration. Without reference to dosage level, the mean times spent standing (P = 0.06), sitting (P < 0.05) and walking (P < 0.05) tended to decrease compared to non-administration. A significant depression in the urinary cortisol level was observed at 7 h after administration (P < 0.05). These results indicate that orally administrated GABA exerts calming effects on dogs as well as humans. © 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.

Interactive effects of glutamine and gamma-aminobutyric acid on growth performance and skeletal muscle amino acid metabolism of 22-42-day-old broilers exposed to hot environment.

PubMed

Hu, Hong; Bai, Xi; Shah, Assar Ali; Dai, Sifa; Wang, Like; Hua, Jinling; Che, Chuanyan; He, Shaojun; Wen, Aiyou; Jiang, Jinpeng

2016-06-01

The present experiment was conducted to investigate the interactive effects between dietary glutamine (Gln, 0 and 5 g/kg) and gamma-aminobutyric acid (GABA, 0 and 100 mg/kg) on growth performance and amino acid (AA) metabolism of broilers under hot environment. A total of 360 22-day-old Arbor Acres male chickens were randomly assigned to five treatment groups under thermoneutral chamber (PC, 23 °C) and cyclic heat stress (HS, 30-34 °C cycling) conditions. Compared with the PC group, cyclic HS decreased (P < 0.05) daily weight gain (DWG), daily feed consumption (DFC), the concentrations of Gln, glutamate (Glu), and GABA, and the activities of glutaminase and glutamic acid decarboxylase (GAD) in breast muscle at 28, 35, and 42 days, while it increased (P < 0.05) the activities of glutamine synthetase (GS) and gamma-aminobutyric acid transaminase (GABA-T) at 28, 35, and 42 days. Dietary Gln and GABA improved (P < 0.05) DWG and DFC of broilers under cyclic HS during 28-42 days. In breast muscle, the Gln supplementation increased (P < 0.05) the concentrations of Gln (28, 35, and 42 days), Glu (28, 35, and 42 days), and GABA (42 days) and the activities of glutaminase (28, 35, and 42 days) and GAD (28, 35, and 42 days) but decreased (P < 0.05) GS activities at 28, 35, and 42 days and GABA-T activities at 28 days. The addition of GABA increased (P < 0.05) the concentrations of Gln and Glu and activities of glutaminase and GAD, while it decreased (P < 0.05) GABA-T activities at 28, 35, and 42 days. Significant interactions (P < 0.05) between Gln and GABA were found on breast skeletal muscle Gln concentrations, glutaminase activities, GS activities at 28 and 35 days, and DWG, GABA concentrations, and GABA-T activities at 28, 35, and 42 days in broilers under cyclic HS. In conclusion, the present results indicated that the interactions of exogenous Gln and GABA could offer a potential nutritional strategy to prevent HS

Interactive effects of glutamine and gamma-aminobutyric acid on growth performance and skeletal muscle amino acid metabolism of 22-42-day-old broilers exposed to hot environment

NASA Astrophysics Data System (ADS)

Hu, Hong; Bai, Xi; Shah, Assar Ali; Dai, Sifa; Wang, Like; Hua, Jinling; Che, Chuanyan; He, Shaojun; Wen, Aiyou; Jiang, Jinpeng

2016-06-01

The present experiment was conducted to investigate the interactive effects between dietary glutamine (Gln, 0 and 5 g/kg) and gamma-aminobutyric acid (GABA, 0 and 100 mg/kg) on growth performance and amino acid (AA) metabolism of broilers under hot environment. A total of 360 22-day-old Arbor Acres male chickens were randomly assigned to five treatment groups under thermoneutral chamber (PC, 23 °C) and cyclic heat stress (HS, 30-34 °C cycling) conditions. Compared with the PC group, cyclic HS decreased ( P < 0.05) daily weight gain (DWG), daily feed consumption (DFC), the concentrations of Gln, glutamate (Glu), and GABA, and the activities of glutaminase and glutamic acid decarboxylase (GAD) in breast muscle at 28, 35, and 42 days, while it increased ( P < 0.05) the activities of glutamine synthetase (GS) and gamma-aminobutyric acid transaminase (GABA-T) at 28, 35, and 42 days. Dietary Gln and GABA improved ( P < 0.05) DWG and DFC of broilers under cyclic HS during 28-42 days. In breast muscle, the Gln supplementation increased ( P < 0.05) the concentrations of Gln (28, 35, and 42 days), Glu (28, 35, and 42 days), and GABA (42 days) and the activities of glutaminase (28, 35, and 42 days) and GAD (28, 35, and 42 days) but decreased ( P < 0.05) GS activities at 28, 35, and 42 days and GABA-T activities at 28 days. The addition of GABA increased ( P < 0.05) the concentrations of Gln and Glu and activities of glutaminase and GAD, while it decreased ( P < 0.05) GABA-T activities at 28, 35, and 42 days. Significant interactions ( P < 0.05) between Gln and GABA were found on breast skeletal muscle Gln concentrations, glutaminase activities, GS activities at 28 and 35 days, and DWG, GABA concentrations, and GABA-T activities at 28, 35, and 42 days in broilers under cyclic HS. In conclusion, the present results indicated that the interactions of exogenous Gln and GABA could offer a potential nutritional strategy to prevent HS-related depression in skeletal muscle Gln and

A comparative density functional theory study of electronic structure and optical properties of γ-aminobutyric acid and its cocrystals with oxalic and benzoic acid

NASA Astrophysics Data System (ADS)

da Silva Filho, J. G.; Freire, V. N.; Caetano, E. W. S.; Ladeira, L. O.; Fulco, U. L.; Albuquerque, E. L.

2013-11-01

In this letter, we study the electronic structure and optical properties of the active medicinal component γ-aminobutyric acid (GABA) and its cocrystals with oxalic (OXA) and benzoic (BZA) acid by means of the density functional theory formalism. It is shown that the cocrystallization strongly weakens the zwitterionic character of the GABA molecule leading to striking differences among the electronic band structures and optical absorption spectra of the GABA crystal and GABA:OXA, GABA:BZA cocrystals, originating from distinct sets of hydrogen bonds. Calculated band widths and Δ-sol band gap estimates indicate that both GABA and GABA:OXA, GABA:BZA cocrystals are indirect gap insulators.

Influence of high-pressure processing on the generation of γ-aminobutyric acid and microbiological safety in coffee beans.

PubMed

Chen, Bang-Yuan; Huang, Hsiao-Wen; Cheng, Ming-Ching; Wang, Chung-Yi

2018-04-27

The aim of this study was to investigate the influence of high-pressure processing (HPP) on γ-aminobutyric acid (GABA) content, glutamic acid (Glu) content, glutamate decarboxylase (GAD) activity, growth of Aspergillus fresenii, and accumulated ochratoxin A (OTA) content in coffee beans. The results indicated that coffee beans subjected to HPP at pressures ≥50 MPa for 5 min increased GAD activity and promoted the conversion of Glu to GABA, and showed a significantly doubling of GABA content compared with unprocessed coffee beans. Additionally, investigation of the influence of HPP on A. fresenii growth on coffee beans showed that application ≥400 MPa reduced A. fresenii concentrations to <1 log. Furthermore, during a 50-day storage period, we observed that a processing pressure of 600 MPa completely inhibited A. fresenii growth, and on day 50 the OTA content of coffee beans subjected to processing pressures of 600 MPa was 0.0066 μg g -1 , which was significantly lower than the OTA content of 0.1143 μg g -1 in the control group. This study shows that HPP treatment can simultaneously increase GABA content and inhibit the growth of A. fresenii, thereby effectively reducing the production and accumulation of OTA and maintaining the microbiological safety of coffee beans. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Exogenous γ-aminobutyric acid treatment affects citrate and amino acid accumulation to improve fruit quality and storage performance of postharvest citrus fruit.

PubMed

Sheng, Ling; Shen, Dandan; Luo, Yi; Sun, Xiaohua; Wang, Jinqiu; Luo, Tao; Zeng, Yunliu; Xu, Juan; Deng, Xiuxin; Cheng, Yunjiang

2017-02-01

The loss of organic acids during postharvest storage is one of the major factors that reduces the fruit quality and economic value of citrus. Citrate is the most important organic acid in citrus fruits. Molecular evidence has proved that γ-aminobutyric acid (GABA) shunt plays a key role in citrate metabolism. Here, we investigated the effects of exogenous GABA treatment on citrate metabolism and storage quality of postharvest citrus fruit. The content of citrate was significantly increased, which was primarily attributed to the inhibition of the expression of glutamate decarboxylase (GAD). Amino acids, including glutamate, alanine, serine, aspartate and proline, were also increased. Moreover, GABA treatment decreased the fruit rot rate. The activities of antioxidant enzymes and the content of energy source ATP were affected by the treatment. Our results indicate that GABA treatment is a very effective approach for postharvest quality maintenance and improvement of storage performance in citrus production. Copyright © 2016 Elsevier Ltd. All rights reserved.

The novel isoxazoline ectoparasiticide lotilaner (Credelio™): a non-competitive antagonist specific to invertebrates γ-aminobutyric acid-gated chloride channels (GABACls).

PubMed

Rufener, Lucien; Danelli, Vanessa; Bertrand, Daniel; Sager, Heinz

2017-11-01

The isoxazolines are a novel class of parasiticides that are potent inhibitors of γ-aminobutyric acid (GABA)-gated chloride channels (GABACls) and, to a lesser extent, of inhibitory glutamate-gated chloride channels (GluCls). Lotilaner (Credelio™), a novel representative of this chemical class, is currently evaluated for its excellent ectoparasiticide properties. In this study, we investigated the molecular mode of action and pharmacology of lotilaner. We report the successful gene identification, cDNA cloning and functional expression in Xenopus oocytes of Drosohpila melanogaster (wild type and dieldrin/fipronil-resistant forms), Lepeophtheirus salmonis (an ectoparasite copepod crustacean of salmon), Rhipicephalus microplus and Canis lupus familiaris GABACls. Automated Xenopus oocyte two-electrode voltage clamp electrophysiology was used to assess GABACls functionality and to compare ion channel inhibition by lotilaner with that of established insecticides addressing GABACls as targets. In these assays, we demonstrated that lotilaner is a potent non-competitive antagonist of insects (fly) GABACls. No cross-resistance with dieldrin or fipronil resistance mutations was detected, suggesting that lotilaner might bind to a site at least partly different from the one bound by known GABACl blockers. Using co-application experiments, we observed that lotilaner antagonism differs significantly from the classical open channel blocker fipronil. We finally confirmed for the first time that isoxazoline compounds are not only powerful antagonists of GABACls of acari (ticks) but also of crustaceans (sea lice), while no activity on a dog GABA A receptor was observed up to a concentration of 10 μM. Together, these results demonstrate that lotilaner is a non-competitive antagonist specific to invertebrate's γ-aminobutyric acid-gated chloride channels (GABACls). They contribute to our understanding of the mode of action of this new ectoparasiticide compound.

Enhancement of γ-aminobutyric acid production in recombinant Corynebacterium glutamicum by co-expressing two glutamate decarboxylase genes from Lactobacillus brevis.

PubMed

Shi, Feng; Jiang, Junjun; Li, Yongfu; Li, Youxin; Xie, Yilong

2013-11-01

γ-Aminobutyric acid (GABA), a non-protein amino acid, is a bioactive component in the food, feed and pharmaceutical fields. To establish an effective single-step production system for GABA, a recombinant Corynebacterium glutamicum strain co-expressing two glutamate decarboxylase (GAD) genes (gadB1 and gadB2) derived from Lactobacillus brevis Lb85 was constructed. Compared with the GABA production of the gadB1 or gadB2 single-expressing strains, GABA production by the gadB1-gadB2 co-expressing strain increased more than twofold. By optimising urea supplementation, the total production of L-glutamate and GABA increased from 22.57 ± 1.24 to 30.18 ± 1.33 g L⁻¹, and GABA production increased from 4.02 ± 0.95 to 18.66 ± 2.11 g L⁻¹ after 84-h cultivation. Under optimal urea supplementation, L-glutamate continued to be consumed, GABA continued to accumulate after 36 h of fermentation, and the pH level fluctuated. GABA production increased to a maximum level of 27.13 ± 0.54 g L⁻¹ after 120-h flask cultivation and 26.32 g L⁻¹ after 60-h fed-batch fermentation. The conversion ratio of L-glutamate to GABA reached 0.60-0.74 mol mol⁻¹. By co-expressing gadB1 and gadB2 and optimising the urea addition method, C. glutamicum was genetically improved for de novo biosynthesis of GABA from its own accumulated L-glutamate.

The Enantiomers of 4-Amino-3-fluorobutanoic Acid as Substrates for γ-Aminobutyric Acid Aminotransferase. Conformational Probes for GABA Binding†

PubMed Central

Clift, Michael; Ji, Haitao; Deniau, Gildas P.; O’Hagan, David; Silverman, Richard B.

2008-01-01

γ-Aminobutyric acid aminotransferase (GABA-AT), a pyridoxal 5’-phosphate dependent enzyme, catalyzes the degradation of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) to succinic semialdehyde with concomitant conversion of pyridoxal 5’-phosphate (PLP) to pyridoxamine 5’-phosphate (PMP). The enzyme then catalyzes the conversion of α-ketoglutarate to the excitatory neurotransmitter L-glutamate. Racemic 4-amino-3-fluorobutanoic acid (3-F-GABA) was shown previously to act as a substrate for GABA-AT, not for transamination, but for HF elimination. Here we report studies of the reaction catalyzed by GABA-AT on (R)- and (S)-3-F-GABA. Neither enantiomer is a substrate for transamination. Very little elimination from the (S)-enantiomer was detected using a coupled enzyme assay; The rate of elimination of HF from the (R)-enantiomer is at least 10 times greater than that for the (S)-enantiomer. The (R)-enantiomer is about 20 times more efficient as a substrate for GABA-AT catalyzed HF elimination than GABA is a substrate for transamination. The (R)-enantiomer also inhibits the transamination of GABA 10 times more effectively than the (S)-enantiomer. Using a combination of computer modeling and the knowledge that vicinal C-F and C-NH3+ bonds have a strong preference to align gauche rather than anti to each other, it is concluded that on binding of free 3-F-GABA to GABA-AT the optimal conformation places the C-NH3+ and C-F bonds gauche in the (R)-enantiomer but anti in the (S)-enantiomer. Furthermore, the dynamic binding process and the bioactive conformation of GABA bound to GABA-AT have been inferred based on the different biological behavior of the two enantiomers of 3-F-GABA when they bind to the enzyme. The present study suggests that the C-F bond can be utilized as a conformational probe to explore the dynamic binding process and provide insight into the bioactive conformation of substrates, which cannot be easily determined by other biophysical

Theoretical study of γ-aminobutyric acid conformers: Intramolecular interactions and ionization energies

NASA Astrophysics Data System (ADS)

Wang, Ke-Dong; Wang, Mei-Ting; Meng, Ju

2014-10-01

Allowing for all combinations of internal single-bond rotamers, 1,296 unique trial structures of γ-Aminobutyric acid (GABA) are obtained. All of these structures are optimized at the M06-2X level of theory and a total of 68 local minimal conformers are found. The nine low-lying conformers are used for further studies. According to the calculated relative Gibbs free energies at M06-2X level of theory, we find that the dispersion is important for the relative energy of GABA. The intramolecular hydrogen bonds and hyperconjugative interaction and their effects on the conformational stability are studied. The results show that both of them have great influence on the conformers. The vertical ionization energies (VIE) are calculated and match the experimental data well. The results show that the neutral GABA in the gas phase is a multi-conformer system and at least four conformations exist.

Expression of functional receptors by the human γ-aminobutyric acid A γ2 subunit

PubMed Central

Martínez-Torres, Ataúlfo; Miledi, Ricardo

2004-01-01

γ-Aminobutyric acid A (GABAA) receptors are heteromeric membrane proteins formed mainly by various combinations of α, β, and γ subunits; and it is commonly thought that the γ2 subunit alone does not form functional receptors. In contrast, we found that cDNA encoding the γ2L subunit of the human GABAA receptor, injected alone into Xenopus oocytes, expressed functional GABA receptors whose properties were investigated by using the two-microelectrode voltage-clamp technique. GABA elicited desensitizing membrane currents that recovered after a few minutes' wash. Repetitive applications of GABA induced a “run-up” of GABA currents that nearly doubled the amplitude of the first response. The GABA currents inverted direction at about -30 mV, indicating that they are carried mainly by Cl- ions. The homomeric γ2L receptors were also activated by β-alanine > taurine > glycine, and, like some types of heteromeric GABAA receptors, the γ2L receptors were blocked by bicuculline and were potentiated by pentobarbital and flunitrazepam. These results indicate that the human γ2L subunit is capable of forming fully functional GABA receptors by itself in Xenopus oocytes and suggest that the roles proposed for the various subunits that make up the heteromeric GABAA receptors in situ require further clarification. PMID:14981251

Acceleration of Aglycone Isoflavone and γ-Aminobutyric Acid Production from Doenjang Using Whole-Cell Biocatalysis Accompanied by Protease Treatment.

PubMed

Li, Yincong; Ku, Seockmo; Park, Myeong Soo; Li, Zhipeng; Ji, Geun Eog

2017-11-28

Recently, soybean isoflavone aglycones ( i.e. , daidzein and genistein) and γ-aminobutyric acid (GABA) have begun to receive considerable consumer attention owing to their potential as nutraceuticals. To produce these ingredients, multiple microorganisms and their enzymes are commonly used for catalysis in the nutraceutical industry. In this work, we introduce a novel fermentation process that uses whole-cell biocatalysis to accelerate GABA and isoflavone aglycone production in doenjang (a traditional Korean soybean paste). Microbial enzymes transform soybean isoflavone glycosides ( i.e. , daidzin and genistin) and monosodium glutamate into soybean isoflavone aglycones and GABA. Lactobacillus brevis GABA 100 and Aspergillus oryzae KACC 40250 significantly reduced the production time with the aid of a protease. The resulting levels of GABA and daidzein were higher, and genistein production resembled the levels in traditional doenjang fermented for over a year. Concentrations of GABA, daidzein, and genistein were measured as 7,162, 60, and 59 μg/g, respectively on the seventh day of fermentation. Our results demonstrate that the administration of whole-cell L. brevis GABA 100 and A. oryzae KACC 40250 paired with a protease treatment is an effective method to accelerate GABA, daidzein, and genistein production in doenjang.

Spectroscopic investigation on structure and pH dependent Cocrystal formation between gamma-aminobutyric acid and benzoic acid

NASA Astrophysics Data System (ADS)

Du, Yong; Xue, Jiadan; Cai, Qiang; Zhang, Qi

2018-02-01

Vibrational spectroscopic methods, including terahertz absorption and Raman scattering spectroscopy, were utilized for the characterization and analysis of gamma-aminobutyric acid (GABA), benzoic acid (BA), and the corresponding GABA-BA cocrystal formation under various pH values of aqueous solution. Vibrational spectroscopic results demonstrated that the solvent GABA-BA cocrystal, similar as grinding counterpart, possessed unique characteristic features compared with that of starting parent compounds. The change of vibrational modes for GABA-BA cocrystal comparing with starting components indicates there is strong inter-molecular interaction between GABA and BA molecules during its cocrystallization process. Formation of GABA-BA cocrystal under slow solvent evaporation is impacted by the pH value of aqueous solution. Vibrational spectra indicate that the GABA-BA cocrystal could be stably formed with the solvent condition of 2.00 ≤ pH ≤ 7.00. In contrast, such cocrystallization did not occur and the cocrystal would dissociate into its parent components when the pH value of solvent is lower than 2.00. This study provides experimental benchmark to discriminate and identify the structure of cocrystal and also pH-dependent cocrystallization effect with vibrational spectroscopic techniques in solid-state pharmaceutical fields.

Hypergravity exposure decreases gamma-aminobutyric acid immunoreactivity in axon terminals contacting pyramidal cells in the rat somatosensory cortex: a quantitative immunocytochemical image analysis

NASA Technical Reports Server (NTRS)

D'Amelio, F.; Wu, L. C.; Fox, R. A.; Daunton, N. G.; Corcoran, M. L.; Polyakov, I.

1998-01-01

Quantitative evaluation of gamma-aminobutyric acid immunoreactivity (GABA-IR) in the hindlimb representation of the rat somatosensory cortex after 14 days of exposure to hypergravity (hyper-G) was conducted by using computer-assisted image processing. The area of GABA-IR axosomatic terminals apposed to pyramidal cells of cortical layer V was reduced in rats exposed to hyper-G compared with control rats, which were exposed either to rotation alone or to vivarium conditions. Based on previous immunocytochemical and behavioral studies, we suggest that this reduction is due to changes in sensory feedback information from muscle receptors. Consequently, priorities for muscle recruitment are altered at the cortical level, and a new pattern of muscle activity is thus generated. It is proposed that the reduction observed in GABA-IR of the terminal area around pyramidal neurons is the immunocytochemical expression of changes in the activity of GABAergic cells that participate in reprogramming motor outputs to achieve effective movement control in response to alterations in the afferent information.

An Allosteric Coagonist Model for Propofol Effects on α1β2γ2L γ-Aminobutyric Acid Type A Receptors

PubMed Central

Ruesch, Dirk; Neumann, Elena; Wulf, Hinnerk; Forman, Stuart A.

2011-01-01

Background Propofol produces its major actions via γ-aminobutyric acid type A (GABAA) receptors. At low concentrations, propofol enhances agonist-stimulated GABAA receptor activity, and high propofol concentrations directly activate receptors. Etomidate produces similar effects, and there is convincing evidence that a single class of etomidate sites mediate both agonist modulation and direct GABAA receptor activation. It is unknown if the propofol binding site(s) on GABAA receptors that modulate agonist-induced activity also mediate direct activation. Methods GABAA α1β2γ2L receptors were heterologously expressed in Xenopus oocytes and activity was quantified using voltage clamp electrophysiology. We tested whether propofol and etomidate display the same linkage between agonist modulation and direct activation of GABAA receptors by identifying equi-efficacious drug solutions for direct activation. We then determined whether these drug solutions produce equal modulation of GABA-induced receptor activity. We also measured propofol-dependent direct activation and modulation of low GABA responses. Allosteric coagonist models similar to that established for etomidate, but with variable numbers of propofol sites, were fitted to combined data. Results Solutions of 19 μM propofol and 10 μM etomidate were found to equally activate GABAA receptors. These two drug solutions also produced indistinguishable modulation of GABA-induced receptor activity. Combined electrophysiological data behaved in a manner consistent with allosteric co-agonist models with more than one propofol site. The best fit was observed when the model assumed three equivalent propofol sites. Conclusions Our results support the hypothesis that propofol, like etomidate, acts at GABAA receptor sites mediating both GABA modulation and direct activation. PMID:22104494

Transcriptional Dysregulation of γ-Aminobutyric Acid Transporter in Parvalbumin-Containing Inhibitory Neurons in the Prefrontal Cortex in Schizophrenia

PubMed Central

Bitanihirwe, Byron K. Y.; Woo, Tsung-Ung W.

2015-01-01

Parvalbumin (PV)-containing neurons are functionally compromised in schizophrenia. Using double in situ hybridization in postmortem human prefrontal cortex, we found that the messenger RNA (mRNA) for the γ-aminobutyric acid transporter GAT-1 was undetectable in 22-41% of PV neurons in layers 3-4 in schizophrenia. In the remaining PV neurons with detectable GAT-1 mRNA, transcript expression was decreased by 26% in layer 3. Hence, the dysfunction of PV neurons involves the molecular dysregulation of presynaptic GABA reuptake. PMID:25312391

Enchancement of Gamma-Aminobutyric Acid Production by Co-Localization of Neurospora crassa OR74A Glutamate Decarboxylase with Escherichia coli GABA Transporter Via Synthetic Scaffold Complex.

PubMed

Somasundaram, Sivachandiran; Maruthamuthu, Murali Kannan; Ganesh, Irisappan; Eom, Gyeong Tae; Hong, Soon Ho

2017-09-28

Gamma-aminobutyric acid is a precursor of nylon-4, which is a promising heat-resistant biopolymer. GABA can be produced from the decarboxylation of glutamate by glutamate decarboxylase. In this study, a synthetic scaffold complex strategy was employed involving the Neurospora crassa glutamate decarboxylase (GadB) and Escherichia coli GABA antiporter (GadC) to improve GABA production. To construct the complex, the SH3 domain was attached to the N. crassa GadB, and the SH3 ligand was attached to the N-terminus, middle, and C-terminus of E. coli GadC. In the C-terminus model, 5.8 g/l of GABA concentration was obtained from 10 g/l glutamate. When a competing pathway engineered strain was used, the final GABA concentration was further increased to 5.94 g/l, which corresponds to 97.5% of GABA yield. With the introduction of the scaffold complex, the GABA productivity increased by 2.9 folds during the initial culture period.

Transcriptional dysregulation of γ-aminobutyric acid transporter in parvalbumin-containing inhibitory neurons in the prefrontal cortex in schizophrenia.

PubMed

Bitanihirwe, Byron K Y; Woo, Tsung-Ung W

2014-12-30

Parvalbumin (PV)-containing neurons are functionally compromised in schizophrenia. Using double in situ hybridization in postmortem human prefrontal cortex, we found that the messenger RNA (mRNA) for the γ-aminobutyric acid (GABA) transporter GAT-1 was undetectable in 22-41% of PV neurons in layers 3-4 in schizophrenia. In the remaining PV neurons with detectable GAT-1 mRNA, transcript expression was decreased by 26% in layer 3. Hence, the dysfunction of PV neurons involves the molecular dysregulation of presynaptic GABA reuptake. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Accumulation of γ‐aminobutyric acid by E nterococcus avium 9184 in scallop solution in a two‐stage fermentation strategy

PubMed Central

Yang, Haoyue; Hu, Linfeng; Liu, Song

2015-01-01

Summary In this study, a new bacterial strain having a high ability to produce γ‐aminobutyric acid (GABA) was isolated from naturally fermented scallop solution and was identified as E nterococcus avium. To the best of our knowledge, this is the first study to prove that E . avium possesses glutamate decarboxylase activity. The strain was then mutagenized with UV radiation and was designated as E . avium 9184. Scallop solution was used as the culture medium to produce GABA. A two‐stage fermentation strategy was applied to accumulate GABA. In the first stage, cell growth was regulated. Optimum conditions for cell growth were pH, 6.5; temperature, 37°C; and glucose concentration, 10 g·L−1. This produced a maximum dry cell mass of 2.10 g·L−1. In the second stage, GABA formation was regulated. GABA concentration reached 3.71 g·L−1 at 96 h pH 6.0, 37°C and initial l‐monosodium glutamate concentration of 10 g·L−1. Thus, compared with traditional one‐stage fermentation, the two‐stage fermentation significantly increased GABA accumulation. These results provide preliminary data to produce GABA using E . avium and also provide a new approach to process and utilize shellfish. PMID:26200650

γ-Aminobutyric acid transaminase deficiency impairs central carbon metabolism and leads to cell wall defects during salt stress in Arabidopsis roots.

PubMed

Renault, Hugues; El Amrani, Abdelhak; Berger, Adeline; Mouille, Grégory; Soubigou-Taconnat, Ludivine; Bouchereau, Alain; Deleu, Carole

2013-05-01

Environmental constraints challenge cell homeostasis and thus require a tight regulation of metabolic activity. We have previously reported that the γ-aminobutyric acid (GABA) metabolism is crucial for Arabidopsis salt tolerance as revealed by the NaCl hypersensitivity of the GABA transaminase (GABA-T, At3g22200) gaba-t/pop2-1 mutant. In this study, we demonstrate that GABA-T deficiency during salt stress causes root and hypocotyl developmental defects and alterations of cell wall composition. A comparative genome-wide transcriptional analysis revealed that expression levels of genes involved in carbon metabolism, particularly sucrose and starch catabolism, were found to increase upon the loss of GABA-T function under salt stress conditions. Consistent with the altered mutant cell wall composition, a number of cell wall-related genes were also found differentially expressed. A targeted quantitative analysis of primary metabolites revealed that glutamate (GABA precursor) accumulated while succinate (the final product of GABA metabolism) significantly decreased in mutant roots after 1 d of NaCl treatment. Furthermore, sugar concentration was twofold reduced in gaba-t/pop2-1 mutant roots compared with wild type. Together, our results provide strong evidence that GABA metabolism is a major route for succinate production in roots and identify GABA as a major player of central carbon adjustment during salt stress. © 2012 Blackwell Publishing Ltd.

Inhibitory actions of the gamma-aminobutyric acid in pediatric Sturge-Weber syndrome.

PubMed

Tyzio, Roman; Khalilov, Ilgam; Represa, Alfonso; Crepel, Valerie; Zilberter, Yuri; Rheims, Sylvain; Aniksztejn, Laurent; Cossart, Rosa; Nardou, Romain; Mukhtarov, Marat; Minlebaev, Marat; Epsztein, Jérôme; Milh, Mathieu; Becq, Helene; Jorquera, Isabel; Bulteau, Christine; Fohlen, Martine; Oliver, Viviana; Dulac, Olivier; Dorfmüller, Georg; Delalande, Olivier; Ben-Ari, Yehezkel; Khazipov, Roustem

2009-08-01

The mechanisms of epileptogenesis in Sturge-Weber syndrome (SWS) are unknown. We explored the properties of neurons from human pediatric SWS cortex in vitro and tested in particular whether gamma-aminobutyric acid (GABA) excites neurons in SWS cortex, as has been suggested for various types of epilepsies. Patch-clamp and field potential recordings and dynamic biphoton imaging were used to analyze cortical tissue samples obtained from four 6- to 14-month-old pediatric SWS patients during surgery. Neurons in SWS cortex were characterized by a relatively depolarized resting membrane potential, as was estimated from cell-attached recordings of N-methyl-D-aspartate channels. Many cells spontaneously fired action potentials at a rate proportional to the level of neuronal depolarization. The reversal potential for GABA-activated currents, assessed by cell-attached single channel recordings, was close to the resting membrane potential. All spontaneously firing neurons recorded in cell-attached mode or imaged with biphoton microscopy were inhibited by GABA. Spontaneous epileptiform activity in the form of recurrent population bursts was suppressed by glutamate receptor antagonists, the GABA(A) receptor agonist isoguvacine, and the positive allosteric GABA(A) modulator diazepam. Blockade of GABA(A) receptors aggravated spontaneous epileptiform activity. The NKCC1 antagonist bumetanide had little effect on epileptiform activity. SWS cortical neurons have a relatively depolarized resting membrane potential and spontaneously fire action potentials that may contribute to increased network excitability. In contrast to previous data depicting excitatory and proconvulsive actions of GABA in certain pediatric and adult epilepsies, GABA plays mainly an inhibitory and anticonvulsive role in SWS pediatric cortex.

Metabolic pathways regulated by γ-aminobutyric acid (GABA) contributing to heat tolerance in creeping bentgrass (Agrostis stolonifera)

PubMed Central

Li, Zhou; Yu, Jingjin; Peng, Yan; Huang, Bingru

2016-01-01

γ-Aminobutyric acid is a non-protein amino acid involved in various metabolic processes. The objectives of this study were to examine whether increased GABA could improve heat tolerance in cool-season creeping bentgrass through physiological analysis, and to determine major metabolic pathways regulated by GABA through metabolic profiling. Plants were pretreated with 0.5 mM GABA or water before exposed to non-stressed condition (21/19 °C) or heat stress (35/30 °C) in controlled growth chambers for 35 d. The growth and physiological analysis demonstrated that exogenous GABA application significantly improved heat tolerance of creeping bentgrass. Metabolic profiling found that exogenous application of GABA led to increases in accumulations of amino acids (glutamic acid, aspartic acid, alanine, threonine, serine, and valine), organic acids (aconitic acid, malic acid, succinic acid, oxalic acid, and threonic acid), sugars (sucrose, fructose, glucose, galactose, and maltose), and sugar alcohols (mannitol and myo-inositol). These findings suggest that GABA-induced heat tolerance in creeping bentgrass could involve the enhancement of photosynthesis and ascorbate-glutathione cycle, the maintenance of osmotic adjustment, and the increase in GABA shunt. The increased GABA shunt could be the supply of intermediates to feed the tricarboxylic acid cycle of respiration metabolism during a long-term heat stress, thereby maintaining metabolic homeostasis. PMID:27455877

Quantification of γ-Aminobutyric Acid in Cerebrospinal Fluid Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry.

PubMed

Arning, Erland; Bottiglieri, Teodoro

2016-01-01

We describe a simple stable isotope dilution method for accurate and precise measurement of γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter in human cerebrospinal fluid (CSF) as a clinical diagnostic test. Determination of GABA in CSF (50 μL) was performed utilizing high performance liquid chromatography coupled with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Analysis of free and total GABA requires two individual sample preparations and mass spectrometry analyses. Free GABA in CSF is determined by a 1:2 dilution with internal standard (GABA-D2) and injected directly onto the HPLC-ESI-MS/MS system. Determination of total GABA in CSF requires additional sample preparation in order to hydrolyze all the bound GABA in the sample to the free form. This requires hydrolyzing the sample by boiling in acidic conditions (hydrochloric acid) for 4 h. The sample is then further diluted 1:10 with a 90 % acetonitrile/0.1 % formic acid solution and injected into the HPLC-ESI-MS/MS system. Each assay is quantified using a five-point standard curve and is linear from 6 nM to 1000 nM and 0.63 μM to 80 μM for free and total GABA, respectively.

Spectroscopic investigation on structure and pH dependent Cocrystal formation between gamma-aminobutyric acid and benzoic acid.

PubMed

Du, Yong; Xue, Jiadan; Cai, Qiang; Zhang, Qi

2018-02-15

Vibrational spectroscopic methods, including terahertz absorption and Raman scattering spectroscopy, were utilized for the characterization and analysis of gamma-aminobutyric acid (GABA), benzoic acid (BA), and the corresponding GABA-BA cocrystal formation under various pH values of aqueous solution. Vibrational spectroscopic results demonstrated that the solvent GABA-BA cocrystal, similar as grinding counterpart, possessed unique characteristic features compared with that of starting parent compounds. The change of vibrational modes for GABA-BA cocrystal comparing with starting components indicates there is strong inter-molecular interaction between GABA and BA molecules during its cocrystallization process. Formation of GABA-BA cocrystal under slow solvent evaporation is impacted by the pH value of aqueous solution. Vibrational spectra indicate that the GABA-BA cocrystal could be stably formed with the solvent condition of 2.00≤pH≤7.00. In contrast, such cocrystallization did not occur and the cocrystal would dissociate into its parent components when the pH value of solvent is lower than 2.00. This study provides experimental benchmark to discriminate and identify the structure of cocrystal and also pH-dependent cocrystallization effect with vibrational spectroscopic techniques in solid-state pharmaceutical fields. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of brain allopregnanolone in the plasticity of γ-aminobutyric acid type A receptor in rat brain during pregnancy and after delivery

PubMed Central

Concas, A.; Mostallino, M. C.; Porcu, P.; Follesa, P.; Barbaccia, M. L.; Trabucchi, M.; Purdy, R. H.; Grisenti, P.; Biggio, G.

1998-01-01

The relation between changes in brain and plasma concentrations of neurosteroids and the function and structure of γ-aminobutyric acid type A (GABAA) receptors in the brain during pregnancy and after delivery was investigated in rats. In contrast with plasma, where all steroids increased in parallel, the kinetics of changes in the cerebrocortical concentrations of progesterone, allopregnanolone (AP), and allotetrahydrodeoxycorticosterone (THDOC) diverged during pregnancy. Progesterone was already maximally increased between days 10 and 15, whereas AP and allotetrahydrodeoxycorticosterone peaked around day 19. The stimulatory effect of muscimol on 36Cl− uptake by cerebrocortical membrane vesicles was decreased on days 15 and 19 of pregnancy and increased 2 days after delivery. Moreover, the expression in cerebral cortex and hippocampus of the mRNA encoding for γ2L GABAA receptor subunit decreased during pregnancy and had returned to control values 2 days after delivery. Also α1,α2, α3, α4, β1, β2, β3, and γ2S mRNAs were measured and failed to change during pregnancy. Subchronic administration of finasteride, a 5α-reductase inhibitor, to pregnant rats reduced the concentrations of AP more in brain than in plasma as well as prevented the decreases in both the stimulatory effect of muscimol on 36Cl− uptake and the decrease of γ2L mRNA observed during pregnancy. These results indicate that the plasticity of GABAA receptors during pregnancy and after delivery is functionally related to fluctuations in endogenous brain concentrations of AP whose rate of synthesis/metabolism appears to differ in the brain, compared with plasma, in pregnant rats. PMID:9789080

γ-Aminobutyric Acid Type A α4, β2, and δ Subunits Assemble to Produce More Than One Functionally Distinct Receptor Type

PubMed Central

Eaton, Megan M.; Bracamontes, John; Shu, Hong-Jin; Li, Ping; Mennerick, Steven; Steinbach, Joe Henry

2014-01-01

Native γ-aminobutyric acid (GABA)A receptors consisting of α4, β1–3, and δ subunits mediate responses to the low, tonic concentration of GABA present in the extracellular milieu. Previous studies on heterologously expressed α4βδ receptors have shown a large degree of variability in functional properties, including sensitivity to the transmitter. We studied properties of α4β2δ receptors employing free subunits and concatemeric constructs, expressed in Xenopus oocytes, HEK 293 cells, and cultured hippocampal neurons. The expression system had a strong effect on the properties of receptors containing free subunits. The midpoint of GABA activation curve was 10 nM for receptors in oocytes versus 2300 nM in HEK cells. Receptors activated by the steroid alfaxalone had an estimated maximal open probability of 0.6 in oocytes and 0.01 in HEK cells. Irrespective of the expression system, receptors resulting from combining the tandem construct β2-δ and a free α4 subunit exhibited large steroid responses. We propose that free α4, β2, and δ subunits assemble in different configurations with distinct properties in oocytes and HEK cells, and that subunit linkage can overcome the expression system-dependent preferential assembly of free subunits. Hippocampal neurons transfected with α4 and the picrotoxin-resistant δ(T269Y) subunit showed large responses to alfaxalone in the presence of picrotoxin, suggesting that α4βδ receptors may assemble in a similar configuration in neurons and oocytes. PMID:25238745

Gi-coupled γ-aminobutyric acid-B receptors cross-regulate phospholipase C and calcium in airway smooth muscle.

PubMed

Mizuta, Kentaro; Mizuta, Fumiko; Xu, Dingbang; Masaki, Eiji; Panettieri, Reynold A; Emala, Charles W

2011-12-01

γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous system, and exerts its actions via both ionotropic (GABA(A)) and metabotropic (GABA(B)) receptors. Although the functional expression of GABA(B) receptors coupled to the G(i) protein was reported for airway smooth muscle, the role of GABA(B) receptors in airway responsiveness remains unclear. We investigated whether G(i)-coupled GABA(B) receptors cross-regulate phospholipase C (PLC), an enzyme classically regulated by G(q)-coupled receptors in human airway smooth muscle cells. Both the GABA(B)-selective agonist baclofen and the endogenous ligand GABA significantly increased the synthesis of inositol phosphate, whereas GABA(A) receptor agonists, muscimol, and 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol exerted no effect. The baclofen-induced synthesis of inositol phosphate and transient increases in [Ca(2+)](i) were blocked by CGP35348 and CGP55845 (selective GABA(B) antagonists), pertussis toxin (PTX, which inactivates the G(i) protein), gallein (a G(βγ) signaling inhibitor), U73122 (an inhibitor of PLC-β), and xestospongin C, an inositol 1,4,5-triphosphate receptor blocker. Baclofen also potentiated the bradykinin-induced synthesis of inositol phosphate and transient increases in [Ca(2+)](i), which were blocked by CGP35348 or PTX. Moreover, baclofen potentiated the substance P-induced contraction of airway smooth muscle in isolated guinea pig tracheal rings. In conclusion, the stimulation of GABA(B) receptors in human airway smooth muscle cells rapidly mobilizes intracellular Ca(2+) stores by the synthesis of inositol phosphate via the activation of PLC-β, which is stimulated by G(βγ) protein liberated from G(i) proteins coupled to GABA(B) receptors. Furthermore, crosstalk between GABA(B) receptors and G(q)-coupled receptors potentiates the synthesis of inositol phosphate, transient increases in [Ca(2+)](i), and smooth muscle contraction through G

Cortical gamma-aminobutyric acid and glutamate in posttraumatic stress disorder and their relationships to self-reported sleep quality.

PubMed

Meyerhoff, Dieter J; Mon, Anderson; Metzler, Thomas; Neylan, Thomas C

2014-05-01

To test if posttraumatic stress disorder (PTSD) is associated with low brain gamma-aminobutyric acid (GABA) levels and if reduced GABA is mediated by poor sleep quality. Laboratory study using in vivo proton magnetic resonance spectroscopy (1H MRS) and behavioral testing. VA Medical Center Research Service, Psychiatry and Radiology. Twenty-seven patients with PTSD (PTSD+) and 18 trauma-exposed controls without PTSD (PTSD-), recruited from United States Army reservists, Army National Guard, and mental health clinics. None. 1H MRS at 4 Tesla yielded spectra from three cortical brain regions. In parieto-occipital and temporal cortices, PTSD+ had lower GABA concentrations than PTSD-. As expected, PTSD+ had higher depressive and anxiety symptom scores and a higher Insomnia Severity Index (ISI) score. Higher ISI correlated with lower GABA and higher glutamate levels in parieto-occipital cortex and tended to correlate with lower GABA in the anterior cingulate. The relationship between parieto-occipital GABA and PTSD diagnosis was fully mediated through insomnia severity. Lower N-acetylaspartate and glutamate concentrations in the anterior cingulate cortex correlated with higher arousal scores, whereas depressive and anxiety symptoms did generally not influence metabolite concentrations. Low brain gamma-aminobutyric acid (GABA) concentration in posttraumatic stress disorder (PTSD) is consistent with most findings in panic and social anxiety disorders. Low GABA associated with poor sleep quality is consistent with the hyperarousal theory of both primary insomnia and PTSD. Our data demonstrate that poor sleep quality mediates low parieto-occipital GABA in PTSD. The findings have implications for PTSD treatment approaches.

Influence of cold stress on contents of soluble sugars, vitamin C and free amino acids including gamma-aminobutyric acid (GABA) in spinach (Spinacia oleracea).

PubMed

Yoon, Young-Eun; Kuppusamy, Saranya; Cho, Kye Man; Kim, Pil Joo; Kwack, Yong-Bum; Lee, Yong Bok

2017-01-15

The contents of soluble sugars (sucrose, fructose, glucose, maltose and raffinose), vitamin C and free amino acids (34 compounds, essential and non-essential) were quantified in open-field and greenhouse-grown spinaches in response to cold stress using liquid chromatography. In general, greenhouse cultivation produced nutritionally high value spinach in a shorter growing period, where the soluble sugars, vitamin C and total amino acids concentrations, including essential were in larger amounts compared to those grown in open-field scenarios. Further, low temperature exposure of spinach during a shorter growth period resulted in the production of spinach with high sucrose, ascorbate, proline, gamma-aminobutyric acid, valine and leucine content, and these constitute the most important energy/nutrient sources. In conclusion, cultivation of spinach in greenhouse at a low temperature (4-7°C) and exposure for a shorter period (7-21days) before harvest is recommended. This strategy will produce a high quality product that people can eat. Copyright © 2016 Elsevier Ltd. All rights reserved.

gamma-Aminobutyric acid production in small and large intestine of normal and germ-free Wistar rats. Influence of food intake and intestinal flora.

PubMed

van Berlo, C L; de Jonge, H R; van den Bogaard, A E; van Eijk, H M; Janssen, M A; Soeters, P B

1987-09-01

In recent hypotheses concerning the pathogenesis of hepatic encephalopathy, gamma-aminobutyric acid (GABA) is claimed to be produced by the colonic flora, although enzymes necessary to generate GABA have been reported to be present in intestinal mucosa. In this study, using normal and germ-free Wistar rats, we determined GABA levels and amino-grams of arterial blood and of venous effluent from small and large bowel. The data indicate that large and small intestinal mucosa significantly contribute to GABA production. In the fasted state GABA concentrations are greater in the venous effluent of the small bowel than in the venous effluent of the large bowel. Feeding increases the arterioportal differences, and uptake in the small bowel is still significantly higher than in the large bowel. This process is not, or can only be to a minor degree, bacterially mediated, because GABA production in the gut both in the fed and fasted state is of similar magnitude in germ-free and normal animals. gamma-Aminobutyric acid release correlates significantly with glutamine uptake in the small bowel of fasted rats. Only a small fraction of the glutamine taken up is needed to account for GABA release, so that conclusions concerning which amino acids may serve as precursors of GABA cannot be drawn. Further studies are needed to delineate the metabolic pathways leading to GABA synthesis.

Anterior Cingulate Cortex γ-Aminobutyric Acid in Depressed Adolescents

PubMed Central

Gabbay, Vilma; Mao, Xiangling; Klein, Rachel G.; Ely, Benjamin A.; Babb, James S.; Panzer, Aviva M.; Alonso, Carmen M.; Shungu, Dikoma C.

2013-01-01

Context Anhedonia, a core symptom of major depressive disorder (MDD) and highly variable among adolescents with MDD, may involve alterations in the major inhibitory amino acid neurotransmitter system of γ-aminobutyric acid (GABA). Objective To test whether anterior cingulate cortex (ACC) GABA levels, measured by proton magnetic resonance spectroscopy, are decreased in adolescents with MDD. The associations of GABA alterations with the presence and severity of anhedonia were explored. Design Case-control, cross-sectional study using single-voxel proton magnetic resonance spectroscopy at 3 T. Setting Two clinical research divisions at 2 teaching hospitals. Participants Twenty psychotropic medication-free adolescents with MDD (10 anhedonic, 12 female, aged 12–19 years) with episode duration of 8 weeks or more and 21 control subjects group matched for sex and age. Main Outcome Measures Anterior cingulate cortex GABA levels expressed as ratios relative to unsuppressed voxel tissue water (w) and anhedonia scores expressed as a continuous variable. Results Compared with control subjects, adolescents with MDD had significantly decreased ACC GABA/w (t= 3.2; P<.003). When subjects with MDD were categorized based on the presence of anhedonia, only anhedonic patients had decreased GABA/w levels compared with control subjects (t=4.08; P<.001; PTukey<.001). Anterior cingulate cortex GABA/w levels were negatively correlated with anhedonia scores for the whole MDD group (r = −0.50; P = .02), as well as for the entire participant sample including the control subjects (r=−0.54; P<.001). Anterior cingulate cortex white matter was also significantly decreased in adolescents with MDD compared with controls (P=.04). Conclusions These findings suggest that GABA, the major inhibitory neurotransmitter in the brain, may be implicated in adolescent MDD and, more specifically, in those with anhedonia. In addition, use of a continuous rather than categorical scale of anhedonia, as in

Missense Gamma-Aminobutyric Acid Receptor Polymorphisms Are Associated with Reaction Time, Motor Time, and Ethanol Effects in Vivo.

PubMed

García-Martín, Elena; Ramos, María I; Cornejo-García, José A; Galván, Segismundo; Perkins, James R; Rodríguez-Santos, Laura; Alonso-Navarro, Hortensia; Jiménez-Jiménez, Félix J; Agúndez, José A G

2018-01-01

Background: The Gamma-aminobutyric acid type A receptor (GABA-A receptor) is affected by ethanol concentrations equivalent to those reached during social drinking. At these concentrations, ethanol usually causes impairment in reaction and motor times in most, but not all, individuals. Objectives: To study the effect of GABA-A receptor variability in motor and reaction times, and the effect of low ethanol doses. Methods: Two hundred and fifty healthy subjects received one single dose of 0.5 g/Kg ethanol per os . Reaction and motor times were determined before ethanol challenge (basal), and when participants reached peak ethanol concentrations. We analyzed all common missense polymorphisms described in the 19 genes coding for the GABA-A receptor subunits by using TaqMan probes. Results: The GABRA6 rs4454083 T/C polymorphisms were related to motor times, with individuals carrying the C/C genotype having faster motor times, both, at basal and at peak ethanol concentrations. The GABRA4 rs2229940 T/T genotype was associated to faster reaction times and with lower ethanol effects, determined as the difference between basal reaction time and reaction time at peak concentrations. All these associations remained significant after correction for multiple comparisons. No significant associations were observed for the common missense SNPs GABRB3 rs12910925, GABRG2 rs211035, GABRE rs1139916, GABRP rs1063310, GABRQ rs3810651, GABRR1 rs12200969 or rs1186902, GABRR2 rs282129, and GABRR3 rs832032. Conclusions: This study provides novel information supporting a role of missense GABA-A receptor polymorphisms in reaction time, motor time and effects of low ethanol doses in vivo .

Effect of “Jian-Pi-Zhi-Dong Decoction” on Gamma-Aminobutyric Acid in a Mouse Model of Tourette Syndrome

PubMed Central

Zhang, Wen; Yu, Wenjing; Wei, Li; Lee, Minkyoung; Wang, Sumei

2014-01-01

The purpose of this study was to explore the positive effects of Jian-Pi-Zhi-Dong Decoction (JPZDD) on Tourette syndrome (TS) by investigating the expression of gamma-aminobutyric acid (GABA) and its type A receptor (GABAAR) in the striatum of a TS mice model. The model was induced by 3,3′-iminodipropionitrile (IDPN) treatment; then mice were divided into 4 groups (n=22, each); control and IDPN groups were gavaged with saline and the remaining 2 groups were gavaged with tiapride and JPZDD. We recorded the stereotypic behaviors of TS mice and measured the content of GABA in striatum by HPLC and GABAAR expression by immunohistochemistry and real-time PCR. Our results showed that JPZDD inhibited the abnormal behaviors of TS model mice and decreased GABA levels and GABAAR protein and mRNA expression in the striatum of TS model mice. In brief, the mechanism by which JPZDD alleviates TS symptoms may be associated with GABAAR expression downregulation in striatum which may regulate GABA metabolism. PMID:24812567

Modulation of ethanol withdrawal-induced anxiety-like behavior during later withdrawals by treatment of early withdrawals with benzodiazepine/gamma-aminobutyric acid ligands.

PubMed

Knapp, Darin J; Overstreet, David H; Breese, George R

2005-04-01

Anxiety states, including those arising during acute or protracted withdrawal periods, may be precipitating factors in alcoholic relapse. Given the cyclical nature of ethanol withdrawal associated with repeated cycles of ethanol intake and abstinence in a pattern that often spans years, meaningful attempts to model ethanol withdrawal-associated anxiety should incorporate cycled ethanol treatments. The studies reported herein examined the effects of gamma-aminobutyric acid-modulating drugs on social interaction behavior-an established model of anxiety-in rats exposed to repeated cycles of ethanol treatment and withdrawal. Rats were exposed to 8 to 12 g/kg/day ethanol during three 7-day dietary cycles (5 days on ethanol diet followed by 2 days on control diet). Ethanol was administered either at hour 4 of withdrawal after cessation of each of the first 2 ethanol cycles or during the final withdrawal only. In other groups, the early withdrawals were treated with alphaxalone, diazepam, PK11159, or flumazenil to block anxiety-like behavior during an untreated later (third) withdrawal. The benzodiazepine inverse agonist DMCM (methyl-6, 7-dymerhoxy-4-ethyl-beta-carboline-3-carboxylate) was also given repeatedly to determine whether it would sensitize anxiety-like behavior during a future withdrawal. Finally, the effects of all drugs on deficits in locomotor behavior were assessed. Pretreatment of earlier withdrawals with alphaxalone, diazepam, ethanol, or flumazenil reduced social interaction deficits during a later withdrawal, but pretreatment with PK11195 did not. In contrast, DMCM administered in lieu of early withdrawals increased social interaction deficits during an untreated later withdrawal. Locomotor deficits were significantly reversed only by the acute ethanol and diazepam treatment during the final withdrawal. Single-dose administration of drugs that enhance or diminish activity at benzodiazepine-gamma-aminobutyric acid- receptors during earlier withdrawals

γ-Aminobutyric Acid (GABA) Production and Angiotensin-I Converting Enzyme (ACE) Inhibitory Activity of Fermented Soybean Containing Sea Tangle by the Co-Culture of Lactobacillus brevis with Aspergillus oryzae.

PubMed

Jang, Eun Kyeong; Kim, Nam Yeun; Ahn, Hyung Jin; Ji, Geun Eog

2015-08-01

To enhance the γ-aminobutyric acid (GABA) content, the optimized fermentation of soybean with added sea tangle extract was evaluated at 30°C and pH 5.0. The medium was first inoculated with Aspergillus oryzae strain FMB S46471 and fermented for 3 days, followed by the subsequent inoculation with Lactobacillus brevis GABA 100. After fermentation for 7 days, the fermented soybean showed approximately 1.9 g/kg GABA and exhibited higher ACE inhibitory activity than the traditional soybean product. Furthermore, several peptides in the fraction containing the highest ACE inhibitory activity were identified. The novel fermented soybean enriched with GABA and ACE inhibitory components has great pharmaceutical and functional food values.

The gamma-aminobutyric acid uptake inhibitor, tiagabine, is anticonvulsant in two animal models of reflex epilepsy.

PubMed

Smith, S E; Parvez, N S; Chapman, A G; Meldrum, B S

1995-02-06

The effects of i.p. administration of the gamma-aminobutyric acid (GABA) uptake inhibitors R(-)N-(4,4-di(3-methylthien-2-yl)-but-3-enyl) nipecotic acid hydrochloride (tiagabine; molecular weight 412.0), (1-(2-(((diphenylmethylene)-amino)oxy)ethyl)-1,2,5,6-tetrahydro-3- pyridinecarboxylic acid hydrochloride (NNC-711; molecular weight 386.9), and (+/-)-nipecotic acid (molecular weight 128.2) are compared with those of carbamazepine (molecular weight 236.3) on sound-induced seizures and locomotor performance in genetically epilepsy-prone (GEP) rats. The ED50 value against clonic seizures (in mumol kg-1 at the time of maximal anticonvulsant effect) for tiagabine was 23 (0.5 h), and for NNC-711 was 72 (1 h), and for carbamazepine was 98 (2 h). (+/-)-Nipecotic acid (0.4-15.6 mmol kg-1) was not anticonvulsant. High doses of NNC-711 (207-310 mumol kg-1) and of (+/-)-nipecotic acid (39-78 mmol kg-1) induced ataxia and myoclonic seizures 0.25-1 h. Tiagabine and carbamazepine did not induce myoclonic seizures and had similar therapeutic indices (locomotor deficit ED50/anticonvulsant ED50) ranging from 0.4 to 1.9. In Papio papio, we observed a reduction in photically induced myoclonic seizures with tiagabine (2.4 mumol kg-1 i.v.) accompanied with neurological impairment. Tiagabine has comparable anticonvulsant action to carbamazepine in rats and has anticonvulsant effects in non-human primates supporting the potential use of inhibitors of GABA uptake as therapy for epilepsy.

Extraction, purification and anti-fatigue activity of γ-aminobutyric acid from mulberry (Morus alba L.) leaves

PubMed Central

Chen, Hengwen; He, Xuanhui; Liu, Yan; Li, Jun; He, Qingyong; Zhang, Cuiying; Wei, Benjun; Zhang, Ye; Wang, Jie

2016-01-01

Mulberry (Morus alba L.) is a tree species of Moraceae widely distributed in Southern China. In the present study, the white crystal of γ-aminobutyric acid (GABA) was purified from mulberry leaves, and its bioactivity was also investigated. The main results were as follows: first, the crude GABA was extracted from mulberry leaves by using biochemical methods. Then, the crude was purified by chromatography over an S-8 macroporous resin, Sephadex G-10, and 732 cation exchange resin to yield a white crystal. Lavage administration and exposure of GABA to male NIH mice showed no adverse effects on their growth and development. In an endurance capacity test, the average loaded-swimming time of medium dose was 111.60% longer than the control (P < 0.01). Further investigations showed that relative to that of model control, the respective blood lactate (BL) concentrations of low- and medium-dose were 28.52% and 28.81% lower (P < 0.05), whereas the levels of blood urea nitrogen (BUN) were 36.83% and 40.54% lower (P < 0.05), and that of liver glycogen (LG) levels were 12.81% and 17.22% lower (P < 0.05). The results indicated that GABA has an advantage over taurine of anti-fatigue effect. These findings were indicative of the anti-fatigue activity of GABA. PMID:26743028

Extraction, purification and anti-fatigue activity of γ-aminobutyric acid from mulberry (Morus alba L.) leaves.

PubMed

Chen, Hengwen; He, Xuanhui; Liu, Yan; Li, Jun; He, Qingyong; Zhang, Cuiying; Wei, Benjun; Zhang, Ye; Wang, Jie

2016-01-08

Mulberry (Morus alba L.) is a tree species of Moraceae widely distributed in Southern China. In the present study, the white crystal of γ-aminobutyric acid (GABA) was purified from mulberry leaves, and its bioactivity was also investigated. The main results were as follows: first, the crude GABA was extracted from mulberry leaves by using biochemical methods. Then, the crude was purified by chromatography over an S-8 macroporous resin, Sephadex G-10, and 732 cation exchange resin to yield a white crystal. Lavage administration and exposure of GABA to male NIH mice showed no adverse effects on their growth and development. In an endurance capacity test, the average loaded-swimming time of medium dose was 111.60% longer than the control (P < 0.01). Further investigations showed that relative to that of model control, the respective blood lactate (BL) concentrations of low- and medium-dose were 28.52% and 28.81% lower (P < 0.05), whereas the levels of blood urea nitrogen (BUN) were 36.83% and 40.54% lower (P < 0.05), and that of liver glycogen (LG) levels were 12.81% and 17.22% lower (P < 0.05). The results indicated that GABA has an advantage over taurine of anti-fatigue effect. These findings were indicative of the anti-fatigue activity of GABA.

Extraction, purification and anti-fatigue activity of γ-aminobutyric acid from mulberry (Morus alba L.) leaves

NASA Astrophysics Data System (ADS)

Chen, Hengwen; He, Xuanhui; Liu, Yan; Li, Jun; He, Qingyong; Zhang, Cuiying; Wei, Benjun; Zhang, Ye; Wang, Jie

2016-01-01

Mulberry (Morus alba L.) is a tree species of Moraceae widely distributed in Southern China. In the present study, the white crystal of γ-aminobutyric acid (GABA) was purified from mulberry leaves, and its bioactivity was also investigated. The main results were as follows: first, the crude GABA was extracted from mulberry leaves by using biochemical methods. Then, the crude was purified by chromatography over an S-8 macroporous resin, Sephadex G-10, and 732 cation exchange resin to yield a white crystal. Lavage administration and exposure of GABA to male NIH mice showed no adverse effects on their growth and development. In an endurance capacity test, the average loaded-swimming time of medium dose was 111.60% longer than the control (P < 0.01). Further investigations showed that relative to that of model control, the respective blood lactate (BL) concentrations of low- and medium-dose were 28.52% and 28.81% lower (P < 0.05), whereas the levels of blood urea nitrogen (BUN) were 36.83% and 40.54% lower (P < 0.05), and that of liver glycogen (LG) levels were 12.81% and 17.22% lower (P < 0.05). The results indicated that GABA has an advantage over taurine of anti-fatigue effect. These findings were indicative of the anti-fatigue activity of GABA.

Proteomic analysis of B-aminobutyric acid priming and aba-induction of drought resistance in crabapple (Malus pumila): effect on general metabolism, the phenylpropanoid pathway and cell wall enzymes

USDA-ARS?s Scientific Manuscript database

In a variety of annual crops and model plants, the xenobiotic compound, DL-beta-aminobutyric acid (BABA), has been shown to enhance disease resistance and increase salt, drought, and thermotolerance. BABA does not activate stress genes directly but rather sensitizes plants to respond more quickly a...

Hydrogel Film-Immobilized Lactobacillus brevis RK03 for γ-Aminobutyric Acid Production

PubMed Central

Hsueh, Yi-Huang; Liaw, Wen-Chang; Kuo, Jen-Min; Deng, Chi-Shin

2017-01-01

Hydrogels of 2-hydroxyethyl methacrylate/polyethylene glycol diacrylate (HEMA/PEGDA) have been extensively studied for their use in biomedical and pharmaceutical applications owing to their nontoxic and highly hydrophilic characteristics. Recently, cells immobilized by HEMA/PEGDA hydrogels have also been studied for enhanced production in fermentation. Hydrogel films of HEMA/PEGDA copolymer were generated by Ultraviolet (UV)-initiated photopolymerization. The hydrogel films were used to immobilize viable Lactobacillus brevis RK03 cells for the bioconversion of monosodium glutamate (MSG) to γ-aminobutyric acid (GABA). The mechanical properties and fermentation yields of the L. brevis RK03 cells immobilized on polyacrylate hydrogel films with different monomeric formulations were investigated. Fermentation was carried out in 75 mL de Man, Rogosa and Sharpe (MRS) medium containing various concentrations of MSG. We found that HEMA (93%)/PEGDA (3%) hydrogels (sample H) maximized GABA production. The conversion rate of MSG to GABA reached a maximum value of 98.4% after 240 h. Bioconversion activity gradually declined after 420 h to 83.8% after five cycles of semi-continuous fermentation. Our results suggest that HEMA (93%)/PEGDA (3%) hydrogels have great potential for use in GABA production via semi-continuous fermentation. PMID:29099794

Non-Neuronal Release of Gamma-Aminobutyric Acid by Embryonic Pluripotent Stem Cells

PubMed Central

Teng, Lin; Tang, Ya-Bin; Sun, Fan; An, Shi-Min; Zhang, Chun; Yang, Xin-Jie; Lv, Hao-Yu; Lu, Qin; Cui, Yong-Yao; Hu, Jin-Jia

2013-01-01

γ-Aminobutyric acid (GABA), the principle inhibitory transmitter in the mature central nervous system, is also involved in activities outside the nervous system. Recent studies have shown that functional GABA receptors are expressed in embryonic stem (ES) cells and these receptors control ES cell proliferation. However, it is not clear whether ES cells have their own GABAergic transmission output machinery that can fulfill GABA release or whether the cells merely process the GABA receptors by receiving and responding to the diffused GABA released elsewhere. To get further insight into this unresolved problem, we detected the repertoire of components for GABA synthesis, storage, reaction, and termination in ES and embryonal carcinoma stem cells by biological assays, and then directly quantified released GABA in the intercellular milieu from these pluripotent stem (PS) cells by an analytical chemical assay based on high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). We found that embryonic PS cells processed a GABAergic circuit machinery and spontaneously released GABA, which suggests the potential that embryonic PS cells could autonomously establish a GABA niche via release of the transmitter. PMID:23799822

Absence of γ-aminobutyric acid-a receptor potentiation in central hypersomnolence disorders.

PubMed

Dauvilliers, Yves; Evangelista, Elisa; Lopez, Regis; Barateau, Lucie; Jaussent, Isabelle; Cens, Thierry; Rousset, Matthieu; Charnet, Pierre

2016-08-01

The pathophysiology of idiopathic hypersomnia (IH) remains unclear. Recently, cerebrospinal fluid (CSF)-induced enhancement of γ-aminobutyric acid (GABA)-A receptor activity was found in patients with IH compared to controls. Fifteen unrelated patients (2 males and 13 females) affected with typical IH, 12 patients (9 males and 3 females) with narcolepsy type 1, and 15 controls (9 males and 6 females) with unspecified hypersomnolence (n = 7) and miscellaneous neurological conditions (n = 8) were included. A lumbar puncture was performed in all participants to measure CSF hypocretin-1 and GABA-A response. We used a voltage-clamp assay on Xenopus oocytes injected with the RNAs that encode the α1 β2 γ2 or the α2 β2 γ2 subunits of the human GABA-A receptor. A sequence of 6 different applications (GABA, GABA/CSF, and CSF alone) with 2 to 4 oocytes per CSF sample was performed in a whole-cell voltage-clamp assay. Representative current traces from oocytes expressing human α1 β2 γ2 or α2 β2 γ2 GABA-A receptors were recorded in response to 6 successive puffs of GABA diluted in the survival medium (SM), showing stable and reliable response. GABA puffs diluted in SM/CSF solution or SM/CSF solution alone showed no significant differences in the CSF of IH, narcolepsy, or control groups. No associations were found between GABA responses, demographic features, disease duration, or disease severity in the whole population or within groups. Using the Xenopus oocyte assay, we found an absence of GABA-A receptor potentiation with CSF from patients with central hypersomnolence disorders, with no significant differences between hypocretin-deficient and non-hypocretin-deficient patients compared to controls. Ann Neurol 2016;80:259-268. © 2016 American Neurological Association.

Utilization of barley or wheat bran to bioconvert glutamate to γ-aminobutyric acid (GABA).

PubMed

Jin, Wen-Jie; Kim, Min-Ju; Kim, Keun-Sung

2013-09-01

This study deals with the utilization of agro-industrial wastes created by barley and wheat bran in the production of a value-added product, γ-aminobutyric acid (GABA). The simple and eco-friendly reaction requires no pretreatment or microbial fermentation steps but uses barley or wheat bran as an enzyme source, glutamate as a substrate, and pyridoxal 5'-phosphate (PLP) as a cofactor. The optimal reaction conditions were determined on the basis of the temperatures and times used for the decarboxylation reactions and the initial concentrations of barley or wheat bran, glutamate, and PLP. The optimal reactions produced 9.2 mM of GABA from 10 mM glutamate, yielding a 92% GABA conversion rate, when barley bran was used and 6.0 mM of GABA from 10 mM glutamate, yielding a 60% GABA conversion rate, when wheat bran was used. The results imply that barley bran is more efficient than wheat bran in the production of GABA. © 2013 Institute of Food Technologists®

Effects of exogenous gamma-aminobutyric acid on α-amylase activity in the aleurone of barley seeds.

PubMed

Sheng, Yidi; Xiao, Huiyuan; Guo, Chunli; Wu, Hong; Wang, Xiaojing

2018-03-03

Gamma-aminobutyric acid (GABA), a nonprotein amino acid, often accumulates in plants exposed to certain environmental stimuli. Previous studies indicated that a closed relationship existed between endogenous GABA and seed germination. However, there are few studies on the effect of exogenous GABA on seed germination. The objective of this study was to explore whether exogenous GABA affected α-amylase activity which the activation is an important stage in seed germination. The level of endogenous GABA in barley seeds rose gradually during germination, suggesting that endogenous GABA was involved in germination. We measured starch degradation under application of various concentration GABA and found that GABA promoted seed starch degradation with a dose-responsive effect. The relationship between GABA and α-amylase activity was investigated by treating barley aleurone with exogenous GABA. The result showed that α-amylase activity began to rise after about 24 h and reached a peak at 48 h. Molecular evidence suggested that GABA increased α-amylase gene expression. We explore the possible roles played by GABA in signal transduction. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

G(o) transduces GABAB-receptor modulation of N-type calcium channels in cultured dorsal root ganglion neurons.

PubMed

Menon-Johansson, A S; Berrow, N; Dolphin, A C

1993-11-01

High-voltage-activated (HVA) calcium channel currents (IBa) were recorded from acutely replated cultured dorsal root ganglion (DRG) neurons. IBa was irreversibly inhibited by 56.9 +/- 2.7% by 1 microM omega-conotoxin-GVIA (omega-CTx-GVIA), whereas the 1,4-dihydropyridine antagonist nicardipine was ineffective. The selective gamma-aminobutyric acidB (GABAB) agonist, (-)-baclofen (50 microM), inhibited the HVA IBa by 30.7 +/- 5.4%. Prior application of omega-CTx-GVIA completely occluded inhibition of the HVA IBa by (-)-baclofen, indicating that in this preparation (-)-baclofen inhibits N-type current. To investigate which G protein subtype was involved, cells were replated in the presence of anti-G protein antisera. Under these conditions the antibodies were shown to enter the cells through transient pores created during the replating procedure. Replating DRGs in the presence of anti-G(o) antiserum, raised against the C-terminal decapeptide of the G alpha o subunit, reduced (-)-baclofen inhibition of the HVA IBa, whereas replating DRGs in the presence of the anti-Gi antiserum did not. Using anti-G alpha o antisera (1:2000) and confocal laser microscopy, G alpha o localisation was investigated in both unreplated and replated neurons. G alpha o immunoreactivity was observed at the plasma membrane, neurites, attachment plaques and perinuclear region, and was particularly pronounced at points of cell-to-cell contact. The plasma membrane G alpha o immunoreactivity was completely blocked by preincubation with the immunising G alpha o undecapeptide (1 microgram.ml-1) for 1 h at 37 degrees C. A similar treatment also blocked recognition of G alpha o in brain membranes on immunoblots.(ABSTRACT TRUNCATED AT 250 WORDS)

Biodiversity and γ-Aminobutyric Acid Production by Lactic Acid Bacteria Isolated from Traditional Alpine Raw Cow's Milk Cheeses

PubMed Central

Nardin, Tiziana; Schiavon, Silvia; Cavazza, Agostino; Larcher, Roberto; Tuohy, Kieran M.

2015-01-01

“Nostrano-cheeses” are traditional alpine cheeses made from raw cow's milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of “Nostrano-cheeses” and evaluated their potential to produce γ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n = 97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated were Lactobacillus paracasei, Streptococcus thermophilus, and Leuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers were Lactobacillus paracasei but other GABA producing species included Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Pediococcus pentosaceus, and Streptococcus thermophilus. No Enterococcus faecalis or Sc. macedonicus isolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was a Sc. thermophilus. PMID:25802859

Biodiversity and γ-aminobutyric acid production by lactic acid bacteria isolated from traditional alpine raw cow's milk cheeses.

PubMed

Franciosi, Elena; Carafa, Ilaria; Nardin, Tiziana; Schiavon, Silvia; Poznanski, Elisa; Cavazza, Agostino; Larcher, Roberto; Tuohy, Kieran M

2015-01-01

"Nostrano-cheeses" are traditional alpine cheeses made from raw cow's milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of "Nostrano-cheeses" and evaluated their potential to produce γ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n = 97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated were Lactobacillus paracasei, Streptococcus thermophilus, and Leuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers were Lactobacillus paracasei but other GABA producing species included Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Pediococcus pentosaceus, and Streptococcus thermophilus. No Enterococcus faecalis or Sc. macedonicus isolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was a Sc. thermophilus.

Overexpression of ppc or deletion of mdh for improving production of γ-aminobutyric acid in recombinant Corynebacterium glutamicum.

PubMed

Shi, Feng; Zhang, Ming; Li, Yongfu

2017-06-01

L-Glutamate decarboxylase (GAD) transforms L-glutamate into γ-aminobutyric acid (GABA). Corynebacterium glutamicum that expresses exogenous GAD gene(s) can synthesize GABA from its own produced L-glutamate. To enhance GABA production in recombinant C. glutamicum strain SH, metabolic engineering strategies were used to improve the supply of the GABA precursor, L-glutamate. Five new strains were constructed here. First, the ppc gene was coexpressed with two GAD genes (gadB1 and gadB2). Then, the mdh gene was deleted in C. glutamicum SH. Next, gadB1-gadB2 and gadB1-gadB2-ppc co-expression plasmids were transformed into C. glutamicum strains SH and Δmdh, resulting in four recombinant GAD strains SE1, SE2, SDE1, and SDE2, respectively. Finally, the mdh gene was overexpressed in mdh-deleted SDE1, generating the mdh-complemented GAD strain SDE3. After fermenting for 72 h, GABA production increased to 26.3 ± 3.4, 24.8 ± 0.7, and 25.5 ± 3.3 g/L in ppc-overexpressed SE2, mdh-deleted SDE1, and mdh-deleted ppc-overexpressed SDE2, respectively, which was higher than that in the control GAD strain SE1 (22.7 ± 0.5 g/L). While in the mdh-complemented SDE3, GABA production decreased to 20.0 ± 0.6 g/L. This study demonstrates that the recombinant strains SE2, SDE1, and SDE2 can be used as candidates for GABA production.

Gamma-aminobutyric acid (GABA) and neuropeptides in neural areas mediating motion-induced emesis

NASA Technical Reports Server (NTRS)

Damelio, F.; Daunton, Nancy G.; Fox, Robert A.

1991-01-01

Immunocytochemical methods were employed to localize the neurotransmitter amino acid gamma-aminobutyric acid and the neuropeptides substance P and Met-enkephalin in the area postrema (AP), area subpostrema (ASP), nucleus of the tractus solitarius (NTS), dorsal motor nucleus of the vagus nerve (DMNV), and lateral vestibular nucleus (LVN). Glutamic acid decarboxylase immunoreactive (GAD-IR) terminals and fibers were observed in the AP and particularly in the ASP. A gradual decrease in the density of terminals was seen towards the solitary complex. The DMNV revealed irregularly scattered GAD-IR terminals within the neuropil or closely surrounding neuronal cell bodies. The LVN, particularly the dorsal division, showed numerous axon terminals which were mostly localize around large neurons and their proximal dendrites. Substance P immunoreactive (SP-IR) terminals and fibers showed high density in the solitary complex, in particular within the lateral division. The ASP showed medium to low density of SP-IR fibers and terminals. The AP exhibited a small number of fibers and terminals irregularly distributed. The DMNV revealed a high density of SP-IR terminals and fibers that were mainly concentrated in the periphery. Very few terminals were detected in the LVN. Met-enkephalin immunoreactive (Met-Enk-IR) fibers and terminals showed high density and uniform distribution in the DMNV. Scattered terminals and fibers were observed in the AP, ASP, and NTS (particularly the lateral division). The very few fibers were observed in the LVN surrounded the neuronal cell bodies. The present report is part of a study designed to investigate the interaction between neuropeptides and conventional neurotransmitters under conditions producing motion sickness and in the process of sensory-motor adaptation.

Specific gamma-aminobutyrate chemotaxis in pseudomonads with different lifestyle.

PubMed

Reyes-Darias, Jose Antonio; García, Vanina; Rico-Jiménez, Miriam; Corral-Lugo, Andrés; Lesouhaitier, Olivier; Juárez-Hernández, Dalia; Yang, Yiling; Bi, Shuangyu; Feuilloley, Marc; Muñoz-Rojas, Jesús; Sourjik, Victor; Krell, Tino

2015-08-01

The PctC chemoreceptor of Pseudomonas aeruginosa mediates chemotaxis with high specificity to gamma-aminobutyric acid (GABA). This compound is present everywhere in nature and has multiple functions, including being a human neurotransmitter or plant signaling compound. Because P. aeruginosa is ubiquitously distributed in nature and able to infect and colonize different hosts, the physiological relevance of GABA taxis is unclear, but it has been suggested that bacterial attraction to neurotransmitters may enhance virulence. We report the identification of McpG as a specific GABA chemoreceptor in non-pathogenic Pseudomonas putida KT2440. As with PctC, GABA was found to bind McpG tightly. The analysis of chimeras comprising the PctC and McpG ligand-binding domains fused to the Tar signaling domain showed very high GABA sensitivities. We also show that PctC inactivation does not alter virulence in Caenorhabditis elegans. Significant amounts of GABA were detected in tomato root exudates, and deletion of mcpG reduced root colonization that requires chemotaxis through agar. The C. elegans data and the detection of a GABA receptor in non-pathogenic species indicate that GABA taxis may not be related to virulence in animal systems but may be of importance in the context of colonization and infection of plant roots by soil-dwelling pseudomonads. © 2015 John Wiley & Sons Ltd.

Amphetamine regulation of acetylcholine and gamma-aminobutyric acid in nucleus accumbens.

PubMed

Lindefors, N; Hurd, Y L; O'Connor, W T; Brené, S; Persson, H; Ungerstedt, U

1992-01-01

In situ hybridization histochemistry and in vivo microdialysis were combined to study the effect of amphetamine on the expression of choline acetyltransferase and glutamate decarboxylase67 mRNA and in vivo release of acetylcholine and GABA in rat medial nucleus accumbens. Differential effects on acetylcholine and GABA neurons by a single challenge injection of amphetamine (1.5 mg/kg, s.c.) were apparent in saline-pretreated and amphetamine-pretreated (same dose, twice daily for the previous seven days) rats. Extracellular acetylcholine levels were increased up to 50% over a prolonged period following both single and repeated amphetamine. In contrast, extracellular concentrations of GABA were gradually decreased to half the control values, but only in rats receiving repeated amphetamine. Although the increase of acetylcholine release was not associated with any change in choline acetyltransferase mRNA levels, the number of neurons expressing high levels of glutamate decarboxylase67 mRNA was decreased (28%) following repeated injections. Thus we suggest that amphetamine decreases extracellular GABA levels by a slow mechanism, associated with the decreased expression of glutamate decarboxylase67 mRNA in a subpopulation of densely labeled neurons in the medial nucleus accumbens. The delayed response by GABA to amphetamine may reflect supersensitivity in the activity of postsynaptic gamma-aminobutyric acid-containing neurons in nucleus accumbens as a consequence of the repeated amphetamine treatment.

[The role of gamma-aminobutyric acid in the mechanism of action of anticonvulsant drugs].

PubMed

Chmielewska, B

2000-01-01

Decreased activity of gamma-aminobutyric acid, the major inhibitory neurotransmitter in CNS can be epileptogenic. Manipulation of the GABA system has been a target for development of antiepileptic drugs. The different ways for augmenting gabaergic inhibition by conventional and new AEDs are presented in this paper. Among the I generation, barbiturates and benzodiazepines are potent anticonvulsants that act as GABA modulators in postsynaptic GABA-A receptor complex but their usefulness is limited by dependence and tolerance to antiseizure activity. The II generation drugs vigabatrin and tiagabine, and to some extent gabapentin have been developed by a rationale strategy and none of them exert direct action in GABA receptors. Only two former drugs exhibit selective, strictly defined activity: vigabatrine is an irreversible inhibitor of GABA-aminotransferase and tiagabine acts as a GABA-uptake inhibitor from synaptic cleft into neurons and glia. Gabapentin binds to a novel receptors in epileptogenic areas in CNS and enhances GABA turnover. Drugs with multiple mechanisms of action, felbamate and topiramate not only potentiate gabaergic inhibition in several ways but also diminish the activity of excitatory amino acids at their NMDA or AMPA receptors; the later mechanism seems to be essential for their potential neuroprotective activity in epileptogenesis. None of gabamimetic drugs provide optimal seizure control but better tolerability of newer ones and well-established mechanisms of action provide possible harmless therapy.

γ-Aminobutyric acid (GABA) concentration inversely correlates with basal perfusion in human occipital lobe

PubMed Central

Donahue, Manus J; Rane, Swati; Hussey, Erin; Mason, Emily; Pradhan, Subechhya; Waddell, Kevin W; Ally, Brandon A

2014-01-01

Commonly used neuroimaging approaches in humans exploit hemodynamic or metabolic indicators of brain function. However, fundamental gaps remain in our ability to relate such hemo-metabolic reactivity to neurotransmission, with recent reports providing paradoxical information regarding the relationship among basal perfusion, functional imaging contrast, and neurotransmission in awake humans. Here, sequential magnetic resonance spectroscopy (MRS) measurements of the primary inhibitory neurotransmitter, γ-aminobutyric acid (GABA+macromolecules normalized by the complex N-acetyl aspartate-N-acetyl aspartyl glutamic acid: [GABA+]/[NAA–NAAG]), and magnetic resonance imaging (MRI) measurements of perfusion, fractional gray-matter volume, and arterial arrival time (AAT) are recorded in human visual cortex from a controlled cohort of young adult male volunteers with neurocognitive battery-confirmed comparable cognitive capacity (3 T; n=16; age=23±3 years). Regression analyses reveal an inverse correlation between [GABA+]/[NAA–NAAG] and perfusion (R=−0.46; P=0.037), yet no relationship between AAT and [GABA+]/[NAA–NAAG] (R=−0.12; P=0.33). Perfusion measurements that do not control for AAT variations reveal reduced correlations between [GABA+]/[NAA–NAAG] and perfusion (R=−0.13; P=0.32). These findings largely reconcile contradictory reports between perfusion and inhibitory tone, and underscore the physiologic origins of the growing literature relating functional imaging signals, hemodynamics, and neurotransmission. PMID:24398941

Dorsolateral prefrontal γ-aminobutyric acid in men predicts individual differences in rash impulsivity.

PubMed

Boy, Frederic; Evans, C John; Edden, Richard A E; Lawrence, Andrew D; Singh, Krish D; Husain, Masud; Sumner, Petroc

2011-11-01

Impulsivity is a multifaceted personality construct associated with numerous psychiatric disorders. Recent research has characterized four facets of impulsivity: "urgency" (the tendency to act rashly especially in the context of distress or cravings); "lack of premeditation" (not envisaging the consequences of actions); "lack of perseverance" (not staying focused on a task); and "sensation seeking" (engaging in exciting activities). Urgency is particularly associated with clinical populations and problematic disinhibited behavior. We used magnetic resonance spectroscopy to measure concentration of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) in the dorsolateral prefrontal cortex (DLPFC) in two cohorts of 12 and 13 participants. We find that variation in trait urgency in healthy men correlates with GABA concentration in the DLPFC. The result was replicated in an independent cohort. More GABA predicted lower urgency scores, consistent with a role in self-control for GABA-mediated inhibitory mechanisms in DLPFC. These findings help account for individual differences in self-control and thus clarify the relationship between GABA and a wide range of psychiatric disorders associated with impaired self-control. Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Gamma-aminobutyric acid (GABA)-B receptor 1 in cerebellar cortex of essential tremor.

PubMed

Luo, C; Rajput, A H; Robinson, C A; Rajput, A

2012-06-01

Some reports suggest cerebellar dysfunction as the basis of essential tremor (ET). Several drugs with the action of gamma-aminobutyric acid (GABA) are known to improve ET. Autopsy studies were performed on brains from nine former patients followed at the Movement Disorders Clinic Saskatchewan, Canada, and compared with five normal control brains. We aimed to measure the concentration of GABA B receptor 1 (GBR1) in the brains of patients who had had ET and to compare them to the GABA concentration in brains of controls. Western blot was used to determine the expression of GBR1 in cerebellar cortex tissue. We found that compared to the controls, the ET brains had three different patterns of GBR1 protein concentration--two with high, four comparable, and three with marginally low levels. There was no association between the age of onset, severity or duration of tremor, the response to alcohol or other drugs and GBR1 level. Thus, we conclude that our study does not support that GBR1 is involved in ET. Further studies are needed to verify these results. Copyright © 2011 Elsevier Ltd. All rights reserved.

Oral administration of γ-aminobutyric acid and γ-oryzanol prevents stress-induced hypoadiponectinemia.

PubMed

Ohara, Kazuyuki; Kiyotani, Yuka; Uchida, Asako; Nagasaka, Reiko; Maehara, Hiroyuki; Kanemoto, Shigeharu; Hori, Masatoshi; Ushio, Hideki

2011-06-15

Metabolic syndrome is a cluster of risk factors including insulin resistance and type 2 diabetes and is found to associate partly with chronic stress at work in human. Adiponectin circulates in mammal blood mainly as a low molecular weight (LMW) trimer, hexamer, and a high molecular weight (HMW) multimers. Low circulating levels of adiponectin are related to metabolic syndrome. We have then investigated the influence of immobilization stress on plasma adiponectin concentrations in mice. Relative LMW and HMW adiponectin levels were markedly reduced by immobilization stress (0.66±0.07 and 0.59±0.06 after 102 h, respectively), significantly different from the control values (p<0.01 and 0.05, respectively). γ-Aminobutyric acid (GABA) and γ-oryzanol abundantly contained in germinated brown rice have some physiological functions. We further investigated the effect of GABA, γ-oryzanol, GABA plus γ-oryzanol on adiponectin levels in mice subjected to immobilization stress. GABA and γ-oryzanol significantly increased the relative LMW and HMW adiponectin levels under immobilization stress (1.10±0.11 and 0.99±0.19 after 102 h, respectively, for GABA; 1.08±0.17 and 1.15±0.17 after 102 h, respectively, for γ-oryzanol). Additionally, the co-administration of GABA and γ-oryzanol also increased both relative LMW and HMW adiponectin levels (1.02±0.07 and 0.99±0.10 after 102 h, respectively) and was effective in an earlier phase from 30 to 54 h. The results indicate that the co-administration of GABA and γ-oryzanol might be effective in preventing stress-induced hypoadiponectinemia in mice and be also a promising tool for improving metabolic syndrome aggravated by chronic stress. Copyright © 2011 Elsevier GmbH. All rights reserved.

Feeding rumen-protected gamma-aminobutyric acid enhances the immune response and antioxidant status of heat-stressed lactating dairy cows.

PubMed

Cheng, Jianbo; Zheng, Nan; Sun, Xianzhi; Li, Songli; Wang, Jiaqi; Zhang, Yangdong

2016-08-01

This experiment was conducted to investigate the effects of rumen-protected gamma-aminobutyric acid (GABA) on immune function and antioxidant status in heat-stressed dairy cows. Sixty Holstein dairy cows were randomly assigned to 1 of 4 treatments according to a completely randomized block design. The treatments consisted of 0 (control), 40, 80, or 120mg of GABA/kg DM from rumen-protected GABA. The trial lasted 10 weeks. The average temperature-humidity indices at 0700, 1400 and 2200h were 78.4, 80.2 and 78.7, respectively. Rectal temperatures decreased linearly at 0700, 1400, and 2200h with increasing GABA. As the GABA increased, the immunoglobulin (Ig) A and IgG contents and the proportions of CD4(+) and CD8(+) T lymphocytes increased linearly (P<0.05), whereas concentrations of interleukin (IL)-2, IL-4, IL-6 and tumor necrosis factor-α (TNF-α) decreased linearly (P<0.05). The activities of superoxide dismutase (SOD), glutathione-peroxidase (GSH-PX) and total antioxidant capacity (T-AOC) increased linearly (P<0.05), whereas malondialdehyde (MDA) content decreased linearly (P<0.05) with increasing GABA. These results indicate that rumen-protected GABA supplementation to heat-stressed dairy cows can improve their immune function and antioxidant activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of γ-aminobutyric acid on digestive enzymes, absorption function, and immune function of intestinal mucosa in heat-stressed chicken.

PubMed

Chen, Z; Xie, J; Wang, B; Tang, J

2014-10-01

To explore the effect of dietary γ-aminobutyric acid (GABA) on digestive enzyme activity, absorption function and immune function of intestinal mucosa in heat-stressed Wenchang chicken were studied. One-day-old male Wenchang chickens were randomly divided into a control group (CK), heat stress group (HS), and GABA+HS group. The chickens from the GABA+HS group were administered with 0.2 mL of GABA solution daily. Chickens from HS and GABA+HS groups were subjected to heat stress treatment at 40 ± 0.5°C for 2 h during 1300 to 1500 h every day. Blood was drawn and 0.5 cm-long duodenum, jejunum, and ileum were collected from the chickens on d 3, 5, 7, 9, 12, and 15. Results showed that the activity of Ca²⁺-Mg²⁺-adenosine triphosphatase (ATPase), Na⁺-K⁺-ATPase, maltase, sucrase, and alkaline phosphatase, the contents of secretory IgA, glutathione, and d-xylose, and the number of lymphocytes in HS group were significantly lower than those in the CK group. Among them, some were rescued after the treatment of GABA as the time extension. For maltase, d-xylose, alkaline phosphatase, and Na⁺-K⁺-ATPase, it required 5 to 7 d for achieving the significant effect. For sucrase, 12 d for the alleviation effect was required. In the case of other parameters, no alleviation was observed during the whole period of the study. We have concluded that HS can inhibit the activity of digestive enzymes and reduce absorption and immune functions of intestinal mucosa. γ-Aminobutyric acid can effectively alleviate these inhibitory effects. ©2014 Poultry Science Association Inc.

High-level production and purification in a functional state of an extrasynaptic gamma-aminobutyric acid type A receptor containing α4β3δ subunits.

PubMed

Zhou, Xiaojuan; Desai, Rooma; Zhang, Yinghui; Stec, Wojciech J; Miller, Keith W; Jounaidi, Youssef

2018-01-01

The inhibitory γ-aminobutyric acid type A receptors are implicated in numerous physiological processes, including cognition and inhibition of neurotransmission, rendering them important molecular targets for many classes of drugs. Functionally, the entire GABAAR family of receptors can be subdivided into phasic, fast acting synaptic receptors, composed of α-, β- and γ-subunits, and tonic extrasynaptic receptors, many of which contain the δ-subunit in addition to α- and β-subunits. Whereas the subunit arrangement of the former group is agreed upon, that of the αβδ GABAARs remains unresolved by electrophysiological and pharmacological research. To resolve such issues will require biophysical techniques that demand quantities of receptor that have been previously unavailable. Therefore, we have engineered a stable cell line with tetracycline inducible expression of human α4-, β3- and N-terminally Flag-tagged δ-subunits. This cell line achieved a specific activity between 15 and 20 pmol [3H]muscimol sites/mg of membrane protein, making it possible to obtain 1 nmole of purified α4β3δ GABAAR from sixty 15-cm culture dishes. When induced, these cells exhibited agonist-induced currents with characteristics comparable to those previously reported for this receptor and a pharmacology that included strong modulation by etomidate and the δ-subunit-specific ligand, DS2. Immunoaffinity purification and reconstitution in CHAPS/asolectin micelles resulted in the retention of equilibrium allosteric interactions between the separate agonist, anesthetic and DS2 sites. Moreover, all three subunits retained glycosylation. The establishment of this well-characterized cell line will allow molecular level studies of tonic receptors to be undertaken.

Expression of gamma-aminobutyric acid rho 1 and rho 1 Delta 450 as gene fusions with the green fluorescent protein.

PubMed

Martinez-Torres, A; Miledi, R

2001-02-13

The functional characteristics and cellular localization of the gamma aminobutyric acid (GABA) rho 1 receptor and its nonfunctional isoform rho 1 Delta 450 were investigated by expressing them as gene fusions with the enhanced version of the green fluorescent protein (GFP). Oocytes injected with rho 1-GFP had receptors that gated chloride channels when activated by GABA. The functional characteristics of these receptors were the same as for those of wild-type rho 1 receptors. Fluorescence, because of the chimeric receptors expressed, was over the whole oocyte but was more intense near the cell surface and more abundant in the animal hemisphere. Similar to the wild type, rho 1 Delta 450-GFP did not lead to the expression of functional GABA receptors, and injected oocytes failed to generate currents even after exposure to high concentrations of GABA. Nonetheless, the fluorescence displayed by oocytes expressing rho 1 Delta 450-GFP was distributed similarly to that of rho 1-GFP. Mammalian cells transfected with the rho 1-GFP or rho 1 Delta 450-GFP constructs showed mostly intracellularly distributed fluorescence in confocal microscope images. A sparse localization of fluorescence was observed in the plasma membrane regardless of the cell line used. We conclude that rho 1 Delta 450 is expressed and transported close to, and perhaps incorporated into, the plasma membrane. Thus, rho 1- and rho 1 Delta 450-GFP fusions provide a powerful tool to visualize the traffic of GABA type C receptors.

Expression of γ-aminobutyric acid ρ1 and ρ1Δ450 as gene fusions with the green fluorescent protein

PubMed Central

Martínez-Torres, Ataúlfo; Miledi, Ricardo

2001-01-01

The functional characteristics and cellular localization of the γaminobutyric acid (GABA) ρ1 receptor and its nonfunctional isoform ρ1Δ450 were investigated by expressing them as gene fusions with the enhanced version of the green fluorescent protein (GFP). Oocytes injected with ρ1-GFP had receptors that gated chloride channels when activated by GABA. The functional characteristics of these receptors were the same as for those of wild-type ρ1 receptors. Fluorescence, because of the chimeric receptors expressed, was over the whole oocyte but was more intense near the cell surface and more abundant in the animal hemisphere. Similar to the wild type, ρ1Δ450-GFP did not lead to the expression of functional GABA receptors, and injected oocytes failed to generate currents even after exposure to high concentrations of GABA. Nonetheless, the fluorescence displayed by oocytes expressing ρ1Δ450-GFP was distributed similarly to that of ρ1-GFP. Mammalian cells transfected with the ρ1-GFP or ρ1Δ450-GFP constructs showed mostly intracellularly distributed fluorescence in confocal microscope images. A sparse localization of fluorescence was observed in the plasma membrane regardless of the cell line used. We conclude that ρ1Δ450 is expressed and transported close to, and perhaps incorporated into, the plasma membrane. Thus, ρ1- and ρ1Δ450-GFP fusions provide a powerful tool to visualize the traffic of GABA type C receptors. PMID:11172056

Effect of Functional Bread Rich in Potassium, γ-Aminobutyric Acid and Angiotensin-Converting Enzyme Inhibitors on Blood Pressure, Glucose Metabolism and Endothelial Function

PubMed Central

Becerra-Tomás, Nerea; Guasch-Ferré, Marta; Quilez, Joan; Merino, Jordi; Ferré, Raimon; Díaz-López, Andrés; Bulló, Mònica; Hernández-Alonso, Pablo; Palau-Galindo, Antoni; Salas-Salvadó, Jordi

2015-01-01

Abstract Because it has been suggested that food rich in γ-aminobutyric acid (GABA) or angiotensin-converting enzyme inhibitor (ACEI) peptides have beneficial effects on blood pressure (BP) and other cardiovascular risk factors, we tested the effects of low-sodium bread, but rich in potassium, GABA, and ACEI peptides on 24-hour BP, glucose metabolism, and endothelial function. A randomized, double-blind, crossover trial was conducted in 30 patients with pre or mild-to-moderate hypertension, comparing three 4-week nutritional interventions separated by 2-week washout periods. Patients were randomly assigned to consume 120 g/day of 1 of the 3 types of bread for each nutritional intervention: conventional wheat bread (CB), low-sodium wheat bread enriched in potassium (LSB), and low-sodium wheat bread rich in potassium, GABA, and ACEI peptides (LSB + G). For each period, 24-hour BP measurements, in vivo endothelial function, and biochemical samples were obtained. After LSB + G consumption, 24-hour ambulatory BP underwent a nonsignificant greater reduction than after the consumption of CB and LSB (0.26 mm Hg in systolic BP and −0.63 mm Hg in diastolic BP for CB; −0.71 mm Hg in systolic BP and −1.08 mm Hg in diastolic BP for LSB; and −0.75 mm Hg in systolic BP and −2.12 mm Hg in diastolic BP for LSB + G, respectively). Diastolic BP at rest decreased significantly during the LSB + G intervention, although there were no significant differences in changes between interventions. There were no significant differences between interventions in terms of changes in in vivo endothelial function, glucose metabolism, and peripheral inflammatory parameters. Compared with the consumption of CB or LSB, no greater beneficial effects on 24-hour BP, endothelial function, or glucose metabolism were demonstrated after the consumption of LSB + G in a population with pre or mild-to-moderate hypertension. Further studies are warranted to clarify the

Gamma-aminobutyric acid (GABA) stimulates pancreatic cancer growth through overexpressing GABAA receptor pi subunit.

PubMed

Takehara, Akio; Hosokawa, Masayo; Eguchi, Hidetoshi; Ohigashi, Hiroaki; Ishikawa, Osamu; Nakamura, Yusuke; Nakagawa, Hidewaki

2007-10-15

Gamma-aminobutyric acid (GABA) functions primarily as an inhibitory neurotransmitter in the mature central nervous system, and GABA/GABA receptors are also present in nonneural tissues, including cancer, but their precise function in nonneuronal or cancerous cells has thus far been poorly defined. Through the genome-wide cDNA microarray analysis of pancreatic ductal adenocarcinoma (PDAC) cells as well as subsequent reverse transcription-PCR and Northern blot analyses, we identified the overexpression of GABA receptor pi subunit (GABRP) in PDAC cells. We also found the expression of this peripheral type GABAA receptor subunit in few adult human organs. Knockdown of endogenous GABRP expression in PDAC cells by small interfering RNA attenuated PDAC cell growth, suggesting its essential role in PDAC cell viability. Notably, the addition of GABA into the cell culture medium promoted the proliferation of GABRP-expressing PDAC cells, but not GABRP-negative cells, and GABAA receptor antagonists inhibited this growth-promoting effect by GABA. The HEK293 cells constitutively expressing exogenous GABRP revealed the growth-promoting effect of GABA treatment. Furthermore, GABA treatment in GABRP-positive cells increased intracellular Ca2+ levels and activated the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/Erk) cascade. Clinical PDAC tissues contained a higher level of GABA than normal pancreas tissues due to the up-regulation of glutamate decarboxylase 1 expression, suggesting their autocrine/paracrine growth-promoting effect in PDACs. These findings imply that GABA and GABRP could play important roles in PDAC development and progression, and that this pathway can be a promising molecular target for the development of new therapeutic strategies for PDAC.

GABA (γ-Aminobutyric Acid) Uptake Via the GABA Permease GabP Represses Virulence Gene Expression in Pseudomonas syringae pv. tomato DC3000.

PubMed

McCraw, S L; Park, D H; Jones, R; Bentley, M A; Rico, A; Ratcliffe, R G; Kruger, N J; Collmer, A; Preston, G M

2016-12-01

The nonprotein amino acid γ-aminobutyric acid (GABA) is the most abundant amino acid in the tomato (Solanum lycopersicum) leaf apoplast and is synthesized by Arabidopsis thaliana in response to infection by the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (hereafter called DC3000). High levels of exogenous GABA have previously been shown to repress the expression of the type III secretion system (T3SS) in DC3000, resulting in reduced elicitation of the hypersensitive response (HR) in the nonhost plant tobacco (Nicotiana tabacum). This study demonstrates that the GABA permease GabP provides the primary mechanism for GABA uptake by DC3000 and that the gabP deletion mutant ΔgabP is insensitive to GABA-mediated repression of T3SS expression. ΔgabP displayed an enhanced ability to elicit the HR in young tobacco leaves and in tobacco plants engineered to produce increased levels of GABA, which supports the hypothesis that GABA uptake via GabP acts to regulate T3SS expression in planta. The observation that P. syringae can be rendered insensitive to GABA through loss of gabP but that gabP is retained by this bacterium suggests that GabP is important for DC3000 in a natural setting, either for nutrition or as a mechanism for regulating gene expression. [Formula: see text] Copyright © 2016 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Anxiety in major depression and cerebrospinal fluid free gamma-aminobutyric acid.

PubMed

Mann, J John; Oquendo, Maria A; Watson, Kalycia Trishana; Boldrini, Maura; Malone, Kevin M; Ellis, Steven P; Sullivan, Gregory; Cooper, Thomas B; Xie, Shan; Currier, Dianne

2014-10-01

Low gamma-aminobutyric acid (GABA) is implicated in both anxiety and depression pathophysiology. They are often comorbid, but most clinical studies have not examined these relationships separately. We investigated the relationship of cerebrospinal fluid (CSF) free GABA to the anxiety and depression components of a major depressive episode (MDE) and to monoamine systems. Patients with a DSM-IV major depressive episode (N = 167: 130 major depressive disorder; 37 bipolar disorder) and healthy volunteers (N = 38) had CSF free GABA measured by gas chromatography mass spectroscopy. Monoamine metabolites were assayed by high performance liquid chromatography. Symptomatology was assessed by Hamilton depression rating scale. Psychic anxiety severity increased with age and correlated with lower CSF free GABA, controlling for age. CSF free GABA declined with age but was not related to depression severity. Other monoamine metabolites correlated positively with CSF GABA but not with psychic anxiety or depression severity. CSF free GABA was lower in MDD compared with bipolar disorder and healthy volunteers. GABA levels did not differ based on a suicide attempt history in mood disorders. Recent exposure to benzodiazepines, but not alcohol or past alcoholism, was associated with a statistical trend for more severe anxiety and lower CSF GABA. Lower CSF GABA may explain increasing severity of psychic anxiety in major depression with increasing age. This relationship is not seen with monoamine metabolites, suggesting treatments targeting the GABAergic system should be evaluated in treatment-resistant anxious major depression and in older patients. © 2014 Wiley Periodicals, Inc.

Optimization of culture conditions for gamma-aminobutyric acid production in fermented adzuki bean milk.

PubMed

Song, Hung Yi; Yu, Roch Chui

2018-01-01

γ-Aminobutyric acid (GABA), a nonprotein amino acid, is widely distributed in nature and fulfills several physiological functions. In this study, various lactic acid strains commonly used to produce fermented milk products were inoculated into adzuki bean milk for producing GABA. The high GABA producing strain was selected in further experiment to improve the GABA production utilizing culture medium optimization. The results demonstrated that adzuki bean milk inoculated with Lactobacillus rhamnosus GG increased GABA content from 0.05 mg/mL to 0.44 mg/mL after 36 hours of fermentation, which showed the greatest elevation in this study. Furthermore, the optimal cultural condition to adzuki bean milk inoculated with L. rhamnosus GG to improve the GABA content was performed using response surface methodology. The results showed that GABA content was dependent on the addition of galactose, monosodium glutamate, and pyridoxine with which the increasing ratios of GABA were 23-38%, 24-68%, and 8-36%, respectively. The optimal culture condition for GABA production of adzuki bean milk was found at the content of 1.44% galactose, 2.27% monosodium glutamate, and 0.20% pyridoxine. Under the optimal cultural condition, the amount of GABA produced in the fermented adzuki bean milk was 1.12 mg/mL, which was 22.4-fold higher than that of the unfermented adzuki bean milk (0.05 mg/100 mL). The results suggested that the optimized cultural condition of adzuki bean milk inoculated with L. rhamnosus GG can increase GABA content for consumers as a daily supplement as suggested. Copyright © 2017. Published by Elsevier B.V.

Enhancement of γ-aminobutyric acid (GABA) in Nham (Thai fermented pork sausage) using starter cultures of Lactobacillus namurensis NH2 and Pediococcus pentosaceus HN8.

PubMed

Ratanaburee, Anussara; Kantachote, Duangporn; Charernjiratrakul, Wilawan; Sukhoom, Ampaitip

2013-10-15

The aim was to produce Nham that was enriched with γ-aminobutyric acid (GABA); therefore two GABA producing lactic acid bacteria (Pediococcus pentosaceus HN8 and Lactobacillus namurensis NH2) were used as starter cultures. By using the central composite design (CCD) we showed that addition of 0.5% monosodium glutamate (MSG) together with an inoculum size of roughly 6logCFU/g of each of the two strains produced a maximal amounts of GABA (4051 mg/kg) in the 'GABA Nham' product. This was higher than any current popular commercial Nham product by roughly 8 times. 'GABA Nham' with the additions of both starters and MSG (TSM) supported maximum populations of lactic acid bacteria (LAB) with a minimum of yeasts and no staphylococci or molds when compared to the controls that had no addition of any starters or MSG (TNN), or only the addition of MSG (TNM), or with only the starter (TSN). Based on proximate analysis among the Nham sets, 'GABA Nham' was low in fat, carbohydrate and energy although its texture and color were slightly different from the control (TNN). However, sensory evaluations of 'GABA Nham' were more acceptable than the controls and commercial Nham products for all tested parameters. Hence, a unique novel 'GABA Nham' fermented pork sausage was successfully developed. © 2013.

Gamma-aminobutyric acid and related molecules in the sea fan Eunicella cavolini (Cnidaria: Octocorallia): a biochemical and immunohistochemical approach.

PubMed

Girosi, Laura; Ferrando, Sara; Beltrame, Francesco; Ciarcia, Gaetano; Diaspro, Alberto; Fato, Marco; Magnone, Mirko; Raiteri, Luca; Ramoino, Paola; Tagliafierro, Grazia

2007-07-01

The aim of this study has been the biochemical demonstration of the presence of gamma-aminobutyric acid (GABA) in the Mediterranean sea fan Eunicella cavolini by means of high-performance liquid chromatography, and the description of the distribution pattern of GABA and its related molecules, glutamic acid decarboxylase (GAD), vesicular GABA transporter (VGAT) and one of the GABA receptors (GABA(B) R) by immunohistochemical methods. The interrelationships of GABA, GAD and GABA receptor immunoreactivity have been established by using double-immunohistochemical methods and confocal microscopy. The immunodetection of monoclonal and/or polyclonal antibodies has revealed GABA immunoreactivity throughout the polyp tissue, both in neuronal and non-neuronal elements. GAD immunoreactivity has been mostly localized in the neuronal compartment, contacting epithelial and muscular elements. GABA(B) R immunoreactivity appears particularly intense in the nematocytes and in the oocyte envelope; its presence in GAD-immunoreactive neurons in the tentacles suggests an autocrine type of regulation. Western blot analysis has confirmed that a GABA(B) R, with a molecular weight of 142 kDa, similar to that of rat brain, is present in E. cavolini polyp tissue. The identification of the sites of the synthesis, vesicular transport, storage and reception of GABA strongly suggests the presence of an almost complete set of GABA-related molecules for the functioning of the GABAergic system in this simple nervous system. The distribution of these different immunoreactivities has allowed us to hypothesize GABA involvement in nematocyst discharge, in body wall and enteric muscular contraction, in neuronal integration and in male gametocyte differentiation.

Characterization of a Potential Probiotic Lactobacillus brevis RK03 and Efficient Production of γ-Aminobutyric Acid in Batch Fermentation.

PubMed

Wu, Chien-Hui; Hsueh, Yi-Huang; Kuo, Jen-Min; Liu, Si-Jia

2018-01-04

Lactic acid bacteria were isolated from fish and evaluated for their γ-aminobutyric acid (GABA)-producing abilities. Out of thirty-two isolates, Lactobacillus brevis RK03 showed the highest GABA production ability. The effects of various fermentation parameters including initial glutamic acid level, culture temperature, initial pH, and incubation time on GABA production were investigated via a singleparameter optimization strategy. For industrial large-scale production, a low-cost GABA producing medium (GM) broth was developed for fermentation with L. brevis RK03. We found that an optimized GM broth recipe of 1% glucose; 2.5% yeast extract; 2 ppm each of CaCO₃, MnSO₄, and Tween 80; and 10 μM pyridoxal phosphate (PLP) resulted in a maximum GABA yield of 62,523 mg/L after 88 h following the addition of 650 mM monosodium glutamate (MSG), for a conversion rate of 93.28%. Our data provide a practical approach for the highly efficient and economic production of GABA. In addition, L. brevis RK03 is highly resistant to gastric acid and bovine bile salt. Thus, the discovery of Lactobacillus strains with the ability to synthesize GABA may offer new opportunities in the design of improved health-promoting functional foods.

Characterization of a Potential Probiotic Lactobacillus brevis RK03 and Efficient Production of γ-Aminobutyric Acid in Batch Fermentation

PubMed Central

Hsueh, Yi-Huang; Kuo, Jen-Min; Liu, Si-Jia

2018-01-01

Lactic acid bacteria were isolated from fish and evaluated for their γ-aminobutyric acid (GABA)-producing abilities. Out of thirty-two isolates, Lactobacillus brevis RK03 showed the highest GABA production ability. The effects of various fermentation parameters including initial glutamic acid level, culture temperature, initial pH, and incubation time on GABA production were investigated via a singleparameter optimization strategy. For industrial large-scale production, a low-cost GABA producing medium (GM) broth was developed for fermentation with L. brevis RK03. We found that an optimized GM broth recipe of 1% glucose; 2.5% yeast extract; 2 ppm each of CaCO3, MnSO4, and Tween 80; and 10 μM pyridoxal phosphate (PLP) resulted in a maximum GABA yield of 62,523 mg/L after 88 h following the addition of 650 mM monosodium glutamate (MSG), for a conversion rate of 93.28%. Our data provide a practical approach for the highly efficient and economic production of GABA. In addition, L. brevis RK03 is highly resistant to gastric acid and bovine bile salt. Thus, the discovery of Lactobacillus strains with the ability to synthesize GABA may offer new opportunities in the design of improved health-promoting functional foods. PMID:29300336

Human α1β3γ2L gamma-aminobutyric acid type A receptors: High-level production and purification in a functional state.

PubMed

Dostalova, Zuzana; Zhou, Xiaojuan; Liu, Aiping; Zhang, Xi; Zhang, Yinghui; Desai, Rooma; Forman, Stuart A; Miller, Keith W

2014-02-01

Gamma-aminobutyric acid type A receptors (GABA(A)Rs) are the most important inhibitory chloride ion channels in the central nervous system and are major targets for a wide variety of drugs. The subunit compositions of GABA(A)Rs determine their function and pharmacological profile. GABAA Rs are heteropentamers of subunits, and (α1)2 (β3)2 (γ2L)1 is a common subtype. Biochemical and biophysical studies of GABA(A)Rs require larger quantities of receptors of defined subunit composition than are currently available. We previously reported high-level production of active human α1β3 GABA(A)R using tetracycline-inducible stable HEK293 cells. Here we extend the strategy to receptors containing three different subunits. We constructed a stable tetracycline-inducible HEK293-TetR cell line expressing human (N)-FLAG-α1β3γ2L-(C)-(GGS)3 GK-1D4 GABA(A)R. These cells achieved expression levels of 70-90 pmol [(3)H]muscimol binding sites/15-cm plate at a specific activity of 15-30 pmol/mg of membrane protein. Incorporation of the γ2 subunit was confirmed by the ratio of [(3)H]flunitrazepam to [(3)H]muscimol binding sites and sensitivity of GABA-induced currents to benzodiazepines and zinc. The α1β3γ2L GABA(A)Rs were solubilized in dodecyl-D-maltoside, purified by anti-FLAG affinity chromatography and reconstituted in CHAPS/asolectin at an overall yield of ∼ 30%. Typical purifications yielded 1.0-1.5 nmoles of [(3)H]muscimol binding sites/60 plates. Receptors with similar properties could be purified by 1D4 affinity chromatography with lower overall yield. The composition of the purified, reconstituted receptors was confirmed by ligand binding, Western blot, and proteomics. Allosteric interactions between etomidate and [(3)H]muscimol binding were maintained in the purified state. © 2013 The Protein Society.

Improved detection sensitivity of γ-aminobutyric acid based on graphene oxide interface on an optical microfiber.

PubMed

Zhou, Jun; Huang, Yunyun; Chen, Chaoyan; Xiao, Aoxiang; Guo, Tuan; Guan, Bai-Ou

2018-05-11

Interfacing bio-recognition elements to optical materials is a longstanding challenge to manufacture sensitive biosensors and inexpensive diagnostic devices. In this work, a graphene oxide (GO) interface has been constructed between silica microfiber and bio-recognition elements to develop an improved γ-aminobutyric acid (GABA) sensing approach. The GO interface, which was located at the site with the strongest evanescent field on the microfiber surface, improved the detection sensitivity by providing a larger platform for more bio-recognition element immobilization, and amplifying surface refractive index change caused by combination between bio-recognition elements and target molecules. Owing to the interface improvement, the microfiber has a three times improved sensitivity of 1.03 nm/log M for GABA detection, and hence a lowest limit of detection of 2.91 × 10-18 M, which is 7 orders of magnitude higher than that without the GO interface. Moreover, the micrometer-sized footprint and non-radioactive nature enable easy implantation in human brains for in vivo applications.

Effects of traditionally used anxiolytic botanicals on enzymes of the gamma-aminobutyric acid (GABA) system.

PubMed

Awad, R; Levac, D; Cybulska, P; Merali, Z; Trudeau, V L; Arnason, J T

2007-09-01

In Canada, the use of botanical natural health products (NHPs) for anxiety disorders is on the rise, and a critical evaluation of their safety and efficacy is required. The purpose of this study was to determine whether commercially available botanicals directly affect the primary brain enzymes responsible for gamma-aminobutyric acid (GABA) metabolism. Anxiolytic plants may interact with either glutamic acid decarboxylase (GAD) or GABA transaminase (GABA-T) and ultimately influence brain GABA levels and neurotransmission. Two in vitro rat brain homogenate assays were developed to determine the inhibitory concentrations (IC50) of aqueous and ethanolic plant extracts. Approximately 70% of all extracts that were tested showed little or no inhibitory effect (IC50 values greater than 1 mg/mL) and are therefore unlikely to affect GABA metabolism as tested. The aqueous extract of Melissa officinalis (lemon balm) exhibited the greatest inhibition of GABA-T activity (IC50 = 0.35 mg/mL). Extracts from Centella asiatica (gotu kola) and Valeriana officinalis (valerian) stimulated GAD activity by over 40% at a dose of 1 mg/mL. On the other hand, both Matricaria recutita (German chamomile) and Humulus lupulus (hops) showed significant inhibition of GAD activity (0.11-0.65 mg/mL). Several of these species may therefore warrant further pharmacological investigation. The relation between enzyme activity and possible in vivo mode of action is discussed.

An autocrine γ-aminobutyric acid signaling system exists in pancreatic β-cell progenitors of fetal and postnatal mice.

PubMed

Feng, Mary M; Xiang, Yun-Yan; Wang, Shuanglian; Lu, Wei-Yang

2013-01-01

Gamma-aminobutyric acid (GABA) is produced and secreted by adult pancreatic β-cells, which also express GABA receptors mediating autocrine signaling and regulating β-cell proliferation. However, whether the autocrine GABA signaling involves in β-cell progenitor development or maturation remains uncertain. By means of immunohistochemistry we analyzed the expression profiles of the GABA synthesizing enzyme glutamic acid decarboxylase (GAD) and the α1-subunit of type-A GABA receptor (GABAARα1) in the pancreas of mice at embryonic day 15.5 (E15.5), E18.5, postnatal day 1 (P1) and P7. Our data showed that at E15.5 the pancreatic and duodenum homeobox-1 (Pdx1) was expressed in the majority of cells in the developing pancreata. Notably, insulin immunoreactivity was identified in a subpopulation of pancreatic cells with a high level of Pdx1 expression. About 80% of the high-level Pdx-1 expressing cells in the pancreas expressed GAD and GABAARα1 at all pancreatic developmental stages. In contrast, only about 30% of the high-level Pdx-1 expressing cells in the E15.5 pancreas expressed insulin; i.e., a large number of GAD/GABAARα1-expressing cells did not express insulin at this early developmental stage. The expression level of GAD and GABAARα1 increased steadily, and progressively more GAD/GABAARα1-expressing cells expressed insulin in the course of pancreatic development. These results suggest that 1) GABA signaling proteins appear in β-cell progenitors prior to insulin expression; and 2) the increased expression of GABA signaling proteins may be involved in β-cell progenitor maturation.

Gas release-based prescreening combined with reversed-phase HPLC quantitation for efficient selection of high-γ-aminobutyric acid (GABA)-producing lactic acid bacteria.

PubMed

Wu, Qinglong; Shah, Nagendra P

2015-02-01

High γ-aminobutyric acid (GABA)-producing lactobacilli are promising for the manufacture of GABA-rich foods and to synthesize GRAS (generally recognized as safe)-grade GABA. However, common chromatography-based screening is time-consuming and inefficient. In the present study, Korean kimchi was used as a model of lactic acid-based fermented foods, and a gas release-based prescreening of potential GABA producers was developed. The ability to produce GABA by potential GABA producers in de Man, Rogosa, and Sharpe medium supplemented with or without monosodium glutamate was further determined by HPLC. Based on the results, 9 isolates were regarded as high GABA producers, and were further genetically identified as Lactobacillus brevis based on the sequences of 16S rRNA gene. Gas release-based prescreening combined with reversed-phase HPLC confirmation was an efficient and cost-effective method to identify high-GABA-producing LAB, which could be good candidates for probiotics. The GABA that is naturally produced by these high-GABA-producing LAB could be used as a food additive. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Molecular size of the gamma-aminobutyric acidA receptor purified from mammalian cerebral cortex.

PubMed

Mamalaki, C; Barnard, E A; Stephenson, F A

1989-01-01

The hydrodynamic behaviour of both the soluble and purified gamma-aminobutyric acidA (GABAA) receptor of bovine or rat cerebral cortex has been investigated in solution in Triton X-100 or in 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulphonate (CHAPS). In all the hydrodynamic separations made, it was found that the binding activities for GABA, benzodiazepine, and (where detectable) t-butylbicyclophosphorothionate comigrated. Conditions were established for gel exclusion chromatography and for sucrose density gradient velocity sedimentation that maintain the GABAA receptor in a nonaggregated form. Using these conditions, the molecular weight of the bovine GABAA receptor in the above-mentioned detergents was calculated using the H2O/2H2O method. A value of Mr 230,000-240,000 was calculated for the bovine pure GABAA receptor purified in sodium deoxycholate/Triton X-100 media. A value of Mr 284,000-290,000 was calculated for the nonaggregated bovine or rat cortex receptor in CHAPS, but the Stokes radius is smaller in the latter than in the former medium and the detergent binding in CHAPS is underestimated. Thus the deduced Mr, 240,000, is the best estimate by this method.

Low single dose gabapentin does not affect prefrontal and occipital gamma-aminobutyric acid concentrations.

PubMed

Preuss, Nora; van der Veen, Jan Willem; Carlson, Paul J; Shen, Jun; Hasler, Gregor

2013-12-01

The γ-aminobutyric acid (GABA) system has been proposed as a target for novel antidepressant and anxiolytic treatments. Emerging evidence suggests that gabapentin (GBP), an anticonvulsant drug that significantly increases brain GABA levels, is effective in the treatment of anxiety disorders. The current study was designed to measure prefrontal and occipital GABA levels in medication-free healthy subjects after taking 0mg, 150mg and 300mg GBP. Subjects were scanned on a 3T scanner using a transmit-receive head coil that provided a relatively homogenous radiofrequency field to obtain spectroscopy measurement in the medial prefrontal (MPFC) and occipital cortex (OCC). There was no dose-dependent effect of GBP on GABA levels in the OCC or MPFC. There was also no effect on Glx, choline or N-acetyl-aspartate concentrations. The previously reported finding of increased GABA levels after GBP treatment is not evident for healthy subjects at the dose of 150 and 300mg. As a result, if subjects are scanned on a 3T scanner, low dose GPB is not useful as an experimental challenge agent on the GABA system. © 2013 Elsevier B.V. All rights reserved.

Gamma-aminobutyric acid-mediated neurotransmission in the pontine reticular formation modulates hypnosis, immobility, and breathing during isoflurane anesthesia.

PubMed

Vanini, Giancarlo; Watson, Christopher J; Lydic, Ralph; Baghdoyan, Helen A

2008-12-01

Many general anesthetics are thought to produce a loss of wakefulness, in part, by enhancing gamma-aminobutyric acid (GABA) neurotransmission. However, GABAergic neurotransmission in the pontine reticular formation promotes wakefulness. This study tested the hypotheses that (1) relative to wakefulness, isoflurane decreases GABA levels in the pontine reticular formation; and (2) pontine reticular formation administration of drugs that increase or decrease GABA levels increases or decreases, respectively, isoflurane induction time. To test hypothesis 1, cats (n = 5) received a craniotomy and permanent electrodes for recording the electroencephalogram and electromyogram. Dialysis samples were collected from the pontine reticular formation during isoflurane anesthesia and wakefulness. GABA levels were quantified using high-performance liquid chromatography. For hypothesis 2, rats (n = 10) were implanted with a guide cannula aimed for the pontine reticular formation. Each rat received microinjections of Ringer's (vehicle control), the GABA uptake inhibitor nipecotic acid, and the GABA synthesis inhibitor 3-mercaptopropionic acid. Rats were then anesthetized with isoflurane, and induction time was quantified as loss of righting reflex. Breathing rate was also measured. Relative to wakefulness, GABA levels were significantly decreased by isoflurane. Increased power in the electroencephalogram and decreased activity in the electromyogram caused by isoflurane covaried with pontine reticular formation GABA levels. Nipecotic acid and 3-mercaptopropionic acid significantly increased and decreased, respectively, isoflurane induction time. Nipecotic acid also increased breathing rate. Decreasing pontine reticular formation GABA levels comprises one mechanism by which isoflurane causes loss of consciousness, altered cortical excitability, muscular hypotonia, and decreased respiratory rate.

Effects of Traumatic Stress Induced in the Juvenile Period on the Expression of Gamma-Aminobutyric Acid Receptor Type A Subunits in Adult Rat Brain

PubMed Central

Lu, Cui Yan; Liu, De Xiang; Jiang, Hong; Ho, Cyrus S. H.; Ho, Roger C. M.

2017-01-01

Studies have found that early traumatic experience significantly increases the risk of posttraumatic stress disorder (PTSD). Gamma-aminobutyric acid (GABA) deficits were proposed to be implicated in development of PTSD, but the alterations of GABA receptor A (GABAAR) subunits induced by early traumatic stress have not been fully elucidated. Furthermore, previous studies suggested that exercise could be more effective than medications in reducing severity of anxiety and depression but the mechanism is unclear. This study used inescapable foot-shock to induce PTSD in juvenile rats and examined their emotional changes using open-field test and elevated plus maze, memory changes using Morris water maze, and the expression of GABAAR subunits (γ2, α2, and α5) in subregions of the brain in the adulthood using western blotting and immunohistochemistry. We aimed to observe the role of GABAAR subunits changes induced by juvenile trauma in the pathogenesis of subsequent PTSD in adulthood. In addition, we investigated the protective effects of exercise for 6 weeks and benzodiazepine (clonazepam) for 2 weeks. This study found that juvenile traumatic stress induced chronic anxiety and spatial memory loss and reduced expression of GABAAR subunits in the adult rat brains. Furthermore, exercise led to significant improvement as compared to short-term BZ treatment. PMID:28352479

Elevated striatal γ-aminobutyric acid in youth with major depressive disorder.

PubMed

Bradley, Kailyn A; Alonso, Carmen M; Mehra, Lushna M; Xu, Junqian; Gabbay, Vilma

2018-06-08

Alterations in γ-aminobutyric acid (GABA) have been hypothesized to play a role in the pathogenesis of psychiatric illness. Our previous work has specifically linked anterior cingulate cortex (ACC) GABA deficits with anhedonia in youth with major depressive disorder (MDD). As anhedonia reflects alterations within the reward circuitry, we sought to extend this investigation and examine GABA levels in another key reward-related region, the striatum, in the same adolescent population. Thirty-six youth [20 with MDD and 16 healthy controls; (HC)], ages 12 to 21 years old, underwent J-edited proton magnetic resonance spectroscopy ( 1 H MRS) whereby GABA levels were measured in striatal and ACC voxels. GABA levels were compared between groups and between voxel positions and were examined in relation to clinical symptomatology, such as depression severity, anhedonia, anxiety, and suicidality. Depressed youth had unexpectedly higher GABA levels in the striatum compared to HC. In both depressed and healthy youth, GABA levels were higher in the striatum than in the ACC, while the differences in depressed youth were greater. Moreover, in depressed youth, higher striatal GABA above the mean of HCs was correlated with lower ACC GABA below the mean of HCs. Striatal GABA was not correlated with clinical symptomatology in this small sample. Together, these findings suggest that higher striatal GABA levels may serve some compensatory function as a result of lower ACC GABA in depressed adolescents. It is also possible that, like lower ACC GABA, higher striatal GABA might simply be another pathological feature of adolescent depression. Copyright © 2018 Elsevier Inc. All rights reserved.

ANXIETY IN MAJOR DEPRESSION AND CEREBROSPINAL FLUID FREE GAMMA-AMINOBUTYRIC ACID

PubMed Central

Mann, J. John; Oquendo, Maria A.; Watson, Kalycia Trishana; Boldrini, Maura; Malone, Kevin M.; Ellis, Steven P.; Sullivan, Gregory; Cooper, Thomas B.; Xie, Shan; Currier, Dianne

2016-01-01

Background Low gamma-aminobutyric acid (GABA) is implicated in both anxiety and depression pathophysiology. They are often comorbid, but most clinical studies have not examined these relationships separately. We investigated the relationship of cerebrospinal fluid (CSF) free GABA to the anxiety and depression components of a major depressive episode (MDE) and to monoamine systems. Methods and Materials Patients with a DSM-IV major depressive episode (N = 167: 130 major depressive disorder; 37 bipolar disorder) and healthy volunteers (N = 38) had CSF free GABA measured by gas chromatography mass spectroscopy. Monoamine metabolites were assayed by high performance liquid chromatography. Symptomatology was assessed by Hamilton depression rating scale. Results Psychic anxiety severity increased with age and correlated with lower CSF free GABA, controlling for age. CSF free GABA declined with age but was not related to depression severity. Other monoamine metabolites correlated positively with CSF GABA but not with psychic anxiety or depression severity. CSF free GABA was lower in MDD compared with bipolar disorder and healthy volunteers. GABA levels did not differ based on a suicide attempt history in mood disorders. Recent exposure to benzodiazepines, but not alcohol or past alcoholism, was associated with a statistical trend for more severe anxiety and lower CSF GABA. Conclusions Lower CSF GABA may explain increasing severity of psychic anxiety in major depression with increasing age. This relationship is not seen with monoamine metabolites, suggesting treatments targeting the GABAergic system should be evaluated in treatment-resistant anxious major depression and in older patients. PMID:24865448

Modulation of Ethanol Withdrawal–Induced Anxiety-Like Behavior During Later Withdrawals by Treatment of Early Withdrawals With Benzodiazepine/γ-Aminobutyric Acid Ligands

PubMed Central

Knapp, Darin J.; Overstreet, David H.; Breese, George R.

2010-01-01

Background Anxiety states, including those arising during acute or protracted withdrawal periods, may be precipitating factors in alcoholic relapse. Given the cyclical nature of ethanol withdrawal associated with repeated cycles of ethanol intake and abstinence in a pattern that often spans years, meaningful attempts to model ethanol withdrawal–associated anxiety should incorporate cycled ethanol treatments. The studies reported herein examined the effects of γ-aminobutyric acid–modulating drugs on social interaction behavior—an established model of anxiety—in rats exposed to repeated cycles of ethanol treatment and withdrawal. Methods Rats were exposed to 8 to 12 g/kg/day ethanol during three 7-day dietary cycles (5 days on ethanol diet followed by 2 days on control diet). Ethanol was administered either at hour 4 of withdrawal after cessation of each of the first 2 ethanol cycles or during the final withdrawal only. In other groups, the early withdrawals were treated with alphaxalone, diazepam, PK11159, or flumazenil to block anxiety-like behavior during an untreated later (third) withdrawal. The benzodiazepine inverse agonist DMCM (methyl–6, 7–dymerhoxy–4–ethyl–beta–carboline–3–carboxylate) was also given repeatedly to determine whether it would sensitize anxiety-like behavior during a future withdrawal. Finally, the effects of all drugs on deficits in locomotor behavior were assessed. Results Pretreatment of earlier withdrawals with alphaxalone, diazepam, ethanol, or flumazenil reduced social interaction deficits during a later withdrawal, but pretreatment with PK11195 did not. In contrast, DMCM administered in lieu of early withdrawals increased social interaction deficits during an untreated later withdrawal. Locomotor deficits were significantly reversed only by the acute ethanol and diazepam treatment during the final withdrawal. Conclusions Single-dose administration of drugs that enhance or diminish activity at benzodiazepine–γ-aminobutyric

Carrier-mediated γ-aminobutyric acid transport across the basolateral membrane of human intestinal Caco-2 cell monolayers.

PubMed

Nielsen, Carsten Uhd; Carstensen, Mette; Brodin, Birger

2012-06-01

The aim of the present study was to investigate the transport of γ-aminobutyric acid (GABA) across the basolateral membrane of intestinal cells. The proton-coupled amino acid transporter, hPAT1, mediates the influx of GABA and GABA mimetic drug substances such as vigabatrin and gaboxadol and the anticancer prodrug δ-aminolevulinic acid across the apical membrane of small intestinal enterocytes. Little is however known about the basolateral transport of these substances. We investigated basolateral transport of GABA in mature Caco-2 cell monolayers using isotope studies. Here we report that, at least two transporters seem to be involved in the basolateral transport of GABA. The basolateral uptake consisted of a high-affinity system with a K(m) of 290 μM and V(max) of 75 pmol cm(-2) min(-1) and a low affinity system with a K(m) of approximately 64 mM and V(max) of 1.6 nmol cm(-2) min(-1). The high-affinity transporter is Na(+) and Cl(-) dependent. The substrate specificity of the high-affinity transporter was further studied and Gly-Sar, Leucine, gaboxadol, sarcosine, lysine, betaine, 5-hydroxythryptophan, proline and glycine reduced the GABA uptake to approximately 44-70% of the GABA uptake in the absence of inhibitor. Other substances such as β-alanine, GABA, 5-aminovaleric acid, taurine and δ-aminolevulinic acid reduced the basolateral GABA uptake to 6-25% of the uptake in the absence of inhibitor. Our results indicate that the distance between the charged amino- and acid-groups is particular important for inhibition of basolateral GABA uptake. Thus, there seems to be a partial substrate overlap between the basolateral GABA transporter and hPAT1, which may prove important for understanding drug interactions at the level of intestinal transport. Copyright © 2012 Elsevier B.V. All rights reserved.

Successful combination immunotherapy of anti-gamma aminobutyric acid (GABA)A receptor antibody-positive encephalitis with extensive multifocal brain lesions.

PubMed

Fukami, Yuki; Okada, Hiroaki; Yoshida, Mari; Yamaguchi, Keiji

2017-08-31

A 78-year old woman who presented with akinetic mutism was admitted to our hospital. Brain MRI showed multifocal increased T 2 /FLAIR signal with extensive cortical-subcortical involvement. We suspected autoimmune encephalitis and the patient received methylprednisolone pulse. Her conscious level gradually recovered, but later relapsed again and presented with refractory status epilepticus. We treated her with intravenous immunoglobulin, plasma exchange and pulsed cyclophosphamide, with satisfactory response. A brain biopsy showed perivascular lymphocytic infiltrates and reactive gliosis. Anti-gamma aminobutyric acid (GABA) A receptor antibodies test came back to be positive after her recovery, and the diagnosis of anti-GABA A receptor antibody-positive encephalitis was made. This is a very rare case where brain biopsies were performed in a patient with anti-GABA A receptor antibody-positive encephalitis.

Overexpression and optimization of glutamate decarboxylase in Lactobacillus plantarum Taj-Apis362 for high gamma-aminobutyric acid production

PubMed Central

Tajabadi, Naser; Baradaran, Ali; Ebrahimpour, Afshin; Rahim, Raha A; Bakar, Fatimah A; Manap, Mohd Yazid A; Mohammed, Abdulkarim S; Saari, Nazamid

2015-01-01

Gamma-aminobutyric acid (GABA) is an important bioactive compound biosynthesized by microorganisms through decarboxylation of glutamate by glutamate decarboxylase (GAD). In this study, a full-length GAD gene was obtained by cloning the template deoxyribonucleic acid to pTZ57R/T vector. The open reading frame of the GAD gene showed the cloned gene was composed of 1410 nucleotides and encoded a 469 amino acids protein. To improve the GABA-production, the GAD gene was cloned into pMG36e-LbGAD, and then expressed in Lactobacillus plantarum Taj-Apis362 cells. The overexpression was confirmed by SDS-PAGE and GAD activity, showing a 53 KDa protein with the enzyme activity increased by sevenfold compared with the original GAD activity. The optimal fermentation conditions for GABA production established using response surface methodology were at glutamic acid concentration of 497.973 mM, temperature 36°C, pH 5.31 and time 60 h. Under the conditions, maximum GABA concentration obtained (11.09 mM) was comparable with the predicted value by the model at 11.23 mM. To our knowledge, this is the first report of successful cloning (clone-back) and overexpression of the LbGAD gene from L. plantarum to L. plantarum cells. The recombinant Lactobacillus could be used as a starter culture for direct incorporation into a food system during fermentation for production of GABA-rich products. PMID:25757029

Evaluation of commercial soy sauce koji strains of Aspergillus oryzae for γ-aminobutyric acid (GABA) production.

PubMed

Ab Kadir, Safuan; Wan-Mohtar, Wan Abd Al Qadr Imad; Mohammad, Rosfarizan; Abdul Halim Lim, Sarina; Sabo Mohammed, Abdulkarim; Saari, Nazamid

2016-10-01

In this study, four selected commercial strains of Aspergillus oryzae were collected from soy sauce koji. These A. oryzae strains designated as NSK, NSZ, NSJ and NST shared similar morphological characteristics with the reference strain (A. oryzae FRR 1675) which confirmed them as A. oryzae species. They were further evaluated for their ability to produce γ-aminobutyric acid (GABA) by cultivating the spore suspension in a broth medium containing 0.4 % (w/v) of glutamic acid as a substrate for GABA production. The results showed that these strains were capable of producing GABA; however, the concentrations differed significantly (P < 0.05) among themselves. Based on the A. oryzae strains, highest GABA concentration was obtained from NSK (194 mg/L) followed by NSZ (63 mg/L), NSJ (51.53 mg/L) and NST (31.66 mg/L). Therefore, A. oryzae NSK was characterized and the sequence was found to be similar to A. oryzae and A. flavus with 99 % similarity. The evolutionary distance (K nuc) between sequences of identical fungal species was calculated and a phylogenetic tree prepared from the K nuc data showed that the isolate belonged to the A. oryzae species. This finding may allow the development of GABA-rich ingredients using A. oryzae NSK as a starter culture for soy sauce production.

Norepinephrine-gamma-aminobutyric acid (GABA) interaction in limbic stress circuits: effects of reboxetine on GABAergic neurons.

PubMed

Herman, James P; Renda, Andrew; Bodie, Bryan

2003-01-15

Reboxetine is a selective norepinephrine (NE) reuptake inhibitor that exerts significant antidepressant action. The current study assessed norepinephrine-gamma-aminobutyric acid (GABA)-ergic mechanisms in reboxetine action, examining glutamic acid decarboxylase (GAD) mRNA expression in limbic neurocircuits following reboxetine within the context of chronic stress. Male rats received 25 mg/kg reboxetine/day, p.o. Reboxetine and vehicle animals were exposed to 1 week of variable stress exposure or handling. Behavioral responses to stress (open field) were tested on day 7, and animals were killed on day 8 to assess neuroendocrine stress responses and limbic GAD65/67 mRNA regulation (in situ hybridization). Reboxetine significantly decreased behavioral reactivity in the open field. Reboxetine administration did not affect expression of GAD65/67 mRNA in handled rats; however, administration to stressed animals reduced GAD67 (but not GAD65) mRNA in the medial amygdaloid nucleus, posteromedial bed nucleus of the stria terminalis, and dentate gyrus. In contrast, GAD65 mRNA expression was increased by reboxetine in the lateral septum of stressed animals. Norepinephrine pathways appear to modulate synthesis of GABA in central limbic stress circuits. Decreases in GABA synthetic capacity suggest reduced activation of stress-excitatory pathways and enhanced activation of stress-inhibitory circuits, and is consistent with a role for GABA in the antidepressant efficacy of NE reuptake inhibitors.

Rescue of deficient amygdala tonic γ-aminobutyric acidergic currents in the Fmr-/y mouse model of fragile X syndrome by a novel γ-aminobutyric acid type A receptor-positive allosteric modulator.

PubMed

Martin, Brandon S; Martinez-Botella, Gabriel; Loya, Carlos M; Salituro, Francesco G; Robichaud, Albert J; Huntsman, Molly M; Ackley, Mike A; Doherty, James J; Corbin, Joshua G

2016-06-01

Alterations in the ratio of excitatory to inhibitory transmission are emerging as a common component of many nervous system disorders, including autism spectrum disorders (ASDs). Tonic γ-aminobutyric acidergic (GABAergic) transmission provided by peri- and extrasynaptic GABA type A (GABAA ) receptors powerfully controls neuronal excitability and plasticity and, therefore, provides a rational therapeutic target for normalizing hyperexcitable networks across a variety of disorders, including ASDs. Our previous studies revealed tonic GABAergic deficits in principal excitatory neurons in the basolateral amygdala (BLA) in the Fmr1(-/y) knockout (KO) mouse model fragile X syndrome. To correct amygdala deficits in tonic GABAergic neurotransmission in Fmr1(-/y) KO mice, we developed a novel positive allosteric modulator of GABAA receptors, SGE-872, based on endogenously active neurosteroids. This study shows that SGE-872 is nearly as potent and twice as efficacious for positively modulating GABAA receptors as its parent molecule, allopregnanolone. Furthermore, at submicromolar concentrations (≤1 μM), SGE-872 is selective for tonic, extrasynaptic α4β3δ-containing GABAA receptors over typical synaptic α1β2γ2 receptors. We further find that SGE-872 strikingly rescues the tonic GABAergic transmission deficit in principal excitatory neurons in the Fmr1(-/y) KO BLA, a structure heavily implicated in the neuropathology of ASDs. Therefore, the potent and selective action of SGE-872 on tonic GABAA receptors containing α4 subunits may represent a novel and highly useful therapeutic avenue for ASDs and related disorders involving hyperexcitability of neuronal networks. © 2015 Wiley Periodicals, Inc.

Dairy Streptococcus thermophilus improves cell viability of Lactobacillus brevis NPS-QW-145 and its γ-aminobutyric acid biosynthesis ability in milk.

PubMed

Wu, Qinglong; Law, Yee-Song; Shah, Nagendra P

2015-08-06

Most high γ-aminobutyric acid (GABA) producers are Lactobacillus brevis of plant origin, which may be not able to ferment milk well due to its poor proteolytic nature as evidenced by the absence of genes encoding extracellular proteinases in its genome. In the present study, two glutamic acid decarboxylase (GAD) genes, gadA and gadB, were found in high GABA-producing L. brevis NPS-QW-145. Co-culturing of this organism with conventional dairy starters was carried out to manufacture GABA-rich fermented milk. It was observed that all the selected strains of Streptococcus thermophilus, but not Lactobacillus delbrueckii subsp. bulgaricus, improved the viability of L. brevis NPS-QW-145 in milk. Only certain strains of S. thermophilus improved the gadA mRNA level in L. brevis NPS-QW-145, thus enhanced GABA biosynthesis by the latter. These results suggest that certain S. thermophilus strains are highly recommended to co-culture with high GABA producer for manufacturing GABA-rich fermented milk.

The Role of Ventral Tegmental Area Gamma-Aminobutyric Acid in Chronic Neuropathic Pain after Spinal Cord Injury in Rats.

PubMed

Ko, Moon Yi; Jang, Eun Young; Lee, June Yeon; Kim, Soo Phil; Whang, Sung Hun; Lee, Bong Hyo; Kim, Hee Young; Yang, Chae Ha; Cho, Hee Jung; Gwak, Young S

2018-04-20

Spinal cord injury (SCI) frequently results in chronic neuropathic pain (CNP). However, the understanding of brain neural circuits in CNP modulation is unclear. The present study examined the changes of ventral tegmental area (VTA) putative GABAergic and dopaminergic neuronal activity with CNP attenuation in rats. SCI was established by T10 clip compression injury (35 g, 1 min) in rats, and neuropathic pain behaviors, in vivo extracellular single-cell recording of putative VTA gamma-aminobutyric acid (GABA)/dopamine neurons, extracellular GABA level, glutamic acid decarboxylase (GAD), and vesicular GABA transporters (VGATs) were measured in the VTA, respectively. The results revealed that extracellular GABA level was significantly increased in the CNP group (50.5 ± 18.9 nM) compared to the sham control group (10.2 ± 1.7 nM). In addition, expression of GAD 65/67 , c-Fos, and VGAT exhibited significant increases in the SCI groups compared to the sham control group. With regard to neuropathic pain behaviors, spontaneous pain measured by ultrasound vocalizations (USVs) and evoked pain measured by paw withdrawal thresholds showed significant alteration, which was reversed by intravenous (i.v.) administration of morphine (0.5-5.0 mg/kg). With regard to in vivo electrophysiology, VTA putative GABAergic neuronal activity (13.6 ± 1.7 spikes/sec) and putative dopaminergic neuronal activity (2.4 ± 0.8 spikes/sec) were increased and decreased, respectively, in the SCI group compared to the sham control group. These neuronal activities were reversed by i.v. administration of morphine. The present study suggests that chronic increase of GABAergic neuronal activity suppresses dopaminergic neuronal activity in the VTA and is responsible for negative emotion and motivation for attenuation of SCI-induced CNP.

Growth, density functional theory (DFT) and spectral studies on L-2-aminobutyric acid -biologically active material

NASA Astrophysics Data System (ADS)

Usha, C.; Santhakumari, R.; Meenakshi, R.; Jayasree, R.; Bhuvaneswari, M.

2017-12-01

Single crystal of L-2-aminobutyric acid (ABA) was grown from water by slow evaporation at room temperature. The crystalline nature of the grown crystal was confirmed using powder X-ray diffraction studies. The grown crystal was subjected to FT-IR, FT-Raman, 1H NMR and 13C NMR spectral analyses to confirm the presence of functional group and molecular structure respectively. Thermal properties were investigated by thermogravimetric and differential thermal analyses. The range and percentage of optical transmission was ascertained by recording UV-vis-NIR spectrum. The electronic charge distribution and reactivity of the molecules within the crystal were studied by HOMO and LUMO analysis and the molecular electrostatic potential (MEP) of the grown crystal was performed using the B3LYP method. The anti-bacterial activities of the crystal were performed by disk diffusion method against the standard bacteria E. coli. The crystal exhibits good anti-bacterial activity. Second harmonic generation efficiency of the powdered ABA crystal was tested using Nd:YAG laser and it is found to be ∼3.3 times that of potassium dihydrogen orthophosphate.

Food deprivation modulates gamma-aminobutyric acid receptors and peripheral benzodiazepine binding sites in rats.

PubMed

Weizman, A; Bidder, M; Fares, F; Gavish, M

1990-12-03

The effect of 5 days of food deprivation followed by 5 days of refeeding on gamma-aminobutyric acid (GABA) receptors, central benzodiazepine receptors (CBR), and peripheral benzodiazepine binding sites (PBzS) was studied in female Sprague-Dawley rats. Starvation induced a decrease in the density of PBzS in peripheral organs: adrenal (35%; P less than 0.001), kidney (33%; P less than 0.01), and heart (34%; P less than 0.001). Restoration of [3H]PK 11195 binding to normal values was observed in all three organs after 5 days of refeeding. The density of PBzS in the ovary, pituitary, and hypothalamus was not affected by starvation. Food deprivation resulted in a 35% decrease in cerebellar GABA receptors (P less than 0.01), while CBR in the hypothalamus and cerebral cortex remained unaltered. The changes in PBzS observed in the heart and kidney may be related to the long-term metabolic stress associated with starvation and to the functional changes occurring in these organs. The down-regulation of the adrenal PBzS is attributable to the suppressive effect of hypercortisolemia on pituitary ACTH release. The reduction in cerebellar GABA receptors may be an adaptive response to food deprivation stress and may be relevant to the proaggressive effect of hunger.

Use of sourdough fermentation and pseudo-cereals and leguminous flours for the making of a functional bread enriched of gamma-aminobutyric acid (GABA).

PubMed

Coda, Rossana; Rizzello, Carlo Giuseppe; Gobbetti, Marco

2010-02-28

Lactobacillus plantarum C48 and Lactococcus lactis subsp. lactis PU1, previously selected for the biosynthesis of gamma-aminobutyric acid (GABA), were used for sourdough fermentation of cereal, pseudo-cereal and leguminous flours. Chickpea, amaranth, quinoa and buckwheat were the flours most suitable to be enriched of GABA. The parameters of sourdough fermentation were optimized. Addition of 0.1mM pyridoxal phosphate, dough yield of 160, inoculum of 5 x 10(7)CFU/g of starter bacteria and fermentation for 24h at 30 degrees C were found to be the optimal conditions. A blend of buckwheat, amaranth, chickpea and quinoa flours (ratio 1:1:5.3:1) was selected and fermented with baker's yeast (non-conventional flour bread, NCB) or with Lb. plantarum C48 sourdough (non-conventional flour sourdough bread, NCSB) and compared to baker's yeast started wheat flour bread (WFB). NCSB had the highest concentration of free amino acids and GABA (ca. 4467 and 504 mg/kg, respectively). The concentration of phenolic compounds and antioxidant activity of NCSB bread was the highest, as well as the rate of in vitro starch hydrolysis was the lowest. Texture analysis showed that sourdough fermentation enhances several characteristics of NCSB with respect to NCB, thus approaching the features of WFB. Sensory analysis showed that sourdough fermentation allowed to get good palatability and overall taste appreciation. (c) 2009 Elsevier B.V. All rights reserved.

Regulation of the substance P-induced contraction via the release of acetylcholine and gamma-aminobutyric acid in the guinea-pig urinary bladder.

PubMed Central

Shirakawa, J.; Nakanishi, T.; Taniyama, K.; Kamidono, S.; Tanaka, C.

1989-01-01

1. The action of substance P (SP) on the release of gamma-aminobutyric acid (GABA) and acetylcholine (ACh) and on contraction were studied in strips of the guinea-pig urinary bladder. Substance P induced a dose-dependent contraction of strips of guinea-pig urinary bladder (EC50 = 1.2 x 10(-9) M). This contraction was not altered by tetrodotoxin, but with a dose of 10(-9) M and less, there was a complete inhibition by 10(-6) M) atropine. Contractions initiated by 3 x 10(-9) M) SP or more were partly inhibited by atropine. The EC50 value of substance P in the presence of atropine was 7.0 x 10(-9) M. 2. Substance P induced a Ca2+-dependent and tetrodotoxin-resistant release of [3H]-acetylcholine (ACh) from strips of urinary bladder preloaded with [3H]-choline (EC50 = 4.9 x 10(-10) M), and this release was antagonized by [D-Pro2,D-Trp7,9] substance P. 3. Bicuculline increased the substance P-induced contraction and the release of [3H]-ACh from the strips. 4. Substance P induced a Ca2+-dependent and tetrodotoxin-sensitive release of [3H]-gamma-aminobutyric acid (GABA) from strips preloaded with [3H]-GABA (EC50 = 2.6 x 10(-9) M), and this release was antagonized by [D-Pro2,D-Trp7,9] substance P. 5. Therefore, substance P appears to exert excitatory effects on the contractility of urinary bladder predominantly by stimulating its own receptor located on the cholinergic nerve terminals. GABA released by substance P inhibits stimulation of the cholinergic neurone. However, the direct action of substance P on the cholinergic neurone is more potent that the indirect action via GABA release. PMID:2479440

Postnatal changes in somatic gamma-aminobutyric acid signalling in the rat hippocampus.

PubMed

Tyzio, Roman; Minlebaev, Marat; Rheims, Sylvain; Ivanov, Anton; Jorquera, Isabelle; Holmes, Gregory L; Zilberter, Yuri; Ben-Ari, Yehezkiel; Khazipov, Rustem

2008-05-01

During postnatal development of the rat hippocampus, gamma-aminobutyric acid (GABA) switches its action on CA3 pyramidal cells from excitatory to inhibitory. To characterize the underlying changes in the GABA reversal potential, we used somatic cell-attached recordings of GABA(A) and N-methyl-D-aspartate channels to monitor the GABA driving force and resting membrane potential, respectively. We found that the GABA driving force is strongly depolarizing during the first postnatal week. The strength of this depolarization rapidly declines with age, although GABA remains slightly depolarizing, by a few millivolts, even in adult neurons. Reduction in the depolarizing GABA driving force was due to a progressive negative shift of the reversal potential of GABA currents. Similar postnatal changes in GABA signalling were also observed using the superfused hippocampus preparation in vivo, and in the hippocampal interneurons in vitro. We also found that in adult pyramidal cells, somatic GABA reversal potential is maintained at a slightly depolarizing level by bicarbonate conductance, chloride-extrusion and chloride-loading systems. Thus, the postnatal excitatory-to-inhibitory switch in somatic GABA signalling is associated with a negative shift of the GABA reversal potential but without a hyperpolarizing switch in the polarity of GABA responses. These results also suggest that in adult CA3 pyramidal cells, somatic GABAergic inhibition takes place essentially through shunting rather than hyperpolarization. Apparent hyperpolarizing GABA responses previously reported in the soma of CA3 pyramidal cells are probably due to cell depolarization during intracellular or whole-cell recordings.

Modelling zwitterions in solution: 3-fluoro-γ-aminobutyric acid (3F-GABA).

PubMed

Cao, Jie; Bjornsson, Ragnar; Bühl, Michael; Thiel, Walter; van Mourik, Tanja

2012-01-02

The conformations and relative stabilities of folded and extended 3-fluoro-γ-aminobutyric acid (3F-GABA) conformers were studied using explicit solvation models. Geometry optimisations in the gas phase with one or two explicit water molecules favour folded and neutral structures containing intramolecular NH···O-C hydrogen bonds. With three or five explicit water molecules zwitterionic minima are obtained, with folded structures being preferred over extended conformers. The stability of folded versus extended zwitterionic conformers increases on going from a PCM continuum solvation model to the microsolvated complexes, though extended structures become less disfavoured with the inclusion of more water molecules. Full explicit solvation was studied with a hybrid quantum-mechanical/molecular-mechanical (QM/MM) scheme and molecular dynamics simulations, including more than 6000 TIP3P water molecules. According to free energies obtained from thermodynamic integration at the PM3/MM level and corrected for B3LYP/MM total energies, the fully extended conformer is more stable than folded ones by about -4.5 kJ mol(-1). B3LYP-computed (3)J(F,H) NMR spin-spin coupling constants, averaged over PM3/MM-MD trajectories, agree best with experiment for this fully extended form, in accordance with the original NMR analysis. The seeming discrepancy between static PCM calculations and experiment noted previously is now resolved. That the inexpensive semiempirical PM3 method performs so well for this archetypical zwitterion is encouraging for further QM/MM studies of biomolecular systems. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Overexpression and optimization of glutamate decarboxylase in Lactobacillus plantarum Taj-Apis362 for high gamma-aminobutyric acid production.

PubMed

Tajabadi, Naser; Baradaran, Ali; Ebrahimpour, Afshin; Rahim, Raha A; Bakar, Fatimah A; Manap, Mohd Yazid A; Mohammed, Abdulkarim S; Saari, Nazamid

2015-07-01

Gamma-aminobutyric acid (GABA) is an important bioactive compound biosynthesized by microorganisms through decarboxylation of glutamate by glutamate decarboxylase (GAD). In this study, a full-length GAD gene was obtained by cloning the template deoxyribonucleic acid to pTZ57R/T vector. The open reading frame of the GAD gene showed the cloned gene was composed of 1410 nucleotides and encoded a 469 amino acids protein. To improve the GABA-production, the GAD gene was cloned into pMG36e-LbGAD, and then expressed in Lactobacillus plantarum Taj-Apis362 cells. The overexpression was confirmed by SDS-PAGE and GAD activity, showing a 53 KDa protein with the enzyme activity increased by sevenfold compared with the original GAD activity. The optimal fermentation conditions for GABA production established using response surface methodology were at glutamic acid concentration of 497.973 mM, temperature 36°C, pH 5.31 and time 60 h. Under the conditions, maximum GABA concentration obtained (11.09 mM) was comparable with the predicted value by the model at 11.23 mM. To our knowledge, this is the first report of successful cloning (clone-back) and overexpression of the LbGAD gene from L. plantarum to L. plantarum cells. The recombinant Lactobacillus could be used as a starter culture for direct incorporation into a food system during fermentation for production of GABA-rich products. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Mechanism of Inactivation of γ-Aminobutyric Acid Aminotransferase by (1S,3S)-3-Amino-4-difluoromethylene-1-cyclopentanoic Acid (CPP-115)

PubMed Central

2016-01-01

γ-Aminobutyric acid aminotransferase (GABA-AT) is a pyridoxal 5′-phosphate (PLP)-dependent enzyme that degrades GABA, the principal inhibitory neurotransmitter in mammalian cells. When the concentration of GABA falls below a threshold level, convulsions can occur. Inhibition of GABA-AT raises GABA levels in the brain, which can terminate seizures as well as have potential therapeutic applications in treating other neurological disorders, including drug addiction. Among the analogues that we previously developed, (1S,3S)-3-amino-4-difluoromethylene-1-cyclopentanoic acid (CPP-115) showed 187 times greater potency than that of vigabatrin, a known inactivator of GABA-AT and approved drug (Sabril) for the treatment of infantile spasms and refractory adult epilepsy. Recently, CPP-115 was shown to have no adverse effects in a Phase I clinical trial. Here we report a novel inactivation mechanism for CPP-115, a mechanism-based inactivator that undergoes GABA-AT-catalyzed hydrolysis of the difluoromethylene group to a carboxylic acid with concomitant loss of two fluoride ions and coenzyme conversion to pyridoxamine 5′-phosphate (PMP). The partition ratio for CPP-115 with GABA-AT is about 2000, releasing cyclopentanone-2,4-dicarboxylate (22) and two other precursors of this compound (20 and 21). Time-dependent inactivation occurs by a conformational change induced by the formation of the aldimine of 4-aminocyclopentane-1,3-dicarboxylic acid and PMP (20), which disrupts an electrostatic interaction between Glu270 and Arg445 to form an electrostatic interaction between Arg445 and the newly formed carboxylate produced by hydrolysis of the difluoromethylene group in CPP-115, resulting in a noncovalent, tightly bound complex. This represents a novel mechanism for inactivation of GABA-AT and a new approach for the design of mechanism-based inactivators in general. PMID:25616005

Mechanism of Inactivation of γ-Aminobutyric Acid Aminotransferase by (1 S ,3 S )-3-Amino-4-difluoromethylene-1-cyclopentanoic Acid (CPP-115)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Hyunbeom; Doud, Emma H.; Wu, Rui

gamma-Aminobutyric acid aminotransferase (GABA-AT) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that degrades GABA, the principal inhibitory neurotransmitter in mammalian cells. When the concentration of GABA falls below a threshold level, convulsions can occur. Inhibition of GABA-AT raises GABA levels in the brain, which can terminate seizures as well as have potential therapeutic applications in treating other neurological disorders, including drug addiction. Among the analogues that we previously developed, (1S,3S)-3-amino-4-difluoromethylene-1-cyclopentanoic acid (CPP-115) showed 187 times greater potency than that of vigabatrin, a known inactivator of GABA-AT and approved drug (Sabril) for the treatment of infantile spasms and refractory adult epilepsy. Recently,more » CPP-115 was shown to have no adverse effects in a Phase I clinical trial. Here we report a novel inactivation mechanism for CPP-115, a mechanism-based inactivator that undergoes GABA-AT-catalyzed hydrolysis of the difluoromethylene group to a carboxylic acid with concomitant loss of two fluoride ions and coenzyme conversion to pyridoxamine 5'-phosphate (PMP). The partition ratio for CPP-115 with GABA-AT is about 2000, releasing cyclopentanone-2,4-dicarboxylate (22) and two other precursors of this compound (20 and 21). Time-dependent inactivation occurs by a conformational change induced by the formation of the aldimine of 4-aminocyclopentane-1,3-dicarboxylic acid and PMP (20), which disrupts an electrostatic interaction between Glu270 and Arg445 to form an electrostatic interaction between Arg445 and the newly formed carboxylate produced by hydrolysis of the difluoromethylene group in CPP-115, resulting in a noncovalent, tightly bound complex. This represents a novel mechanism for inactivation of GABA-AT and a new approach for the design of mechanism-based inactivators in general.« less

Mechanism of inactivation of γ-aminobutyric acid aminotransferase by (1S,3S)-3-amino-4-difluoromethylene-1-cyclopentanoic acid (CPP-115).

PubMed

Lee, Hyunbeom; Doud, Emma H; Wu, Rui; Sanishvili, Ruslan; Juncosa, Jose I; Liu, Dali; Kelleher, Neil L; Silverman, Richard B

2015-02-25

γ-Aminobutyric acid aminotransferase (GABA-AT) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that degrades GABA, the principal inhibitory neurotransmitter in mammalian cells. When the concentration of GABA falls below a threshold level, convulsions can occur. Inhibition of GABA-AT raises GABA levels in the brain, which can terminate seizures as well as have potential therapeutic applications in treating other neurological disorders, including drug addiction. Among the analogues that we previously developed, (1S,3S)-3-amino-4-difluoromethylene-1-cyclopentanoic acid (CPP-115) showed 187 times greater potency than that of vigabatrin, a known inactivator of GABA-AT and approved drug (Sabril) for the treatment of infantile spasms and refractory adult epilepsy. Recently, CPP-115 was shown to have no adverse effects in a Phase I clinical trial. Here we report a novel inactivation mechanism for CPP-115, a mechanism-based inactivator that undergoes GABA-AT-catalyzed hydrolysis of the difluoromethylene group to a carboxylic acid with concomitant loss of two fluoride ions and coenzyme conversion to pyridoxamine 5'-phosphate (PMP). The partition ratio for CPP-115 with GABA-AT is about 2000, releasing cyclopentanone-2,4-dicarboxylate (22) and two other precursors of this compound (20 and 21). Time-dependent inactivation occurs by a conformational change induced by the formation of the aldimine of 4-aminocyclopentane-1,3-dicarboxylic acid and PMP (20), which disrupts an electrostatic interaction between Glu270 and Arg445 to form an electrostatic interaction between Arg445 and the newly formed carboxylate produced by hydrolysis of the difluoromethylene group in CPP-115, resulting in a noncovalent, tightly bound complex. This represents a novel mechanism for inactivation of GABA-AT and a new approach for the design of mechanism-based inactivators in general.

Mechanism of Inactivation of γ-Aminobutyric Acid Aminotransferase by (1 S ,3 S)-3-Amino-4-difluoromethylene-1-cyclopentanoic Acid (CPP-115)

DOE PAGES

Lee, Hyunbeom; Doud, Emma H.; Wu, Rui; ...

2015-01-23

γ-Aminobutyric acid aminotransferase (GABA-AT) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that degrades GABA, the principal inhibitory neurotransmitter in mammalian cells. When the concentration of GABA falls below a threshold level, convulsions can occur. Inhibition of GABA-AT raises GABA levels in the brain, which can terminate seizures as well as have potential therapeutic applications in treating other neurological disorders, including drug addiction. Among the analogues that we previously developed, (1S,3S)-3-amino-4-difluoromethylene-1-cyclopentanoic acid (CPP-115) showed 187 times greater potency than that of vigabatrin, a known inactivator of GABA-AT and approved drug (Sabril) for the treatment of infantile spasms and refractory adult epilepsy. Recently,more » CPP-115 was shown to have no adverse effects in a Phase I clinical trial. Here we report a novel inactivation mechanism for CPP-115, a mechanism-based inactivator that undergoes GABA-AT-catalyzed hydrolysis of the difluoromethylene group to a carboxylic acid with concomitant loss of two fluoride ions and coenzyme conversion to pyridoxamine 5'-phosphate (PMP). The partition ratio for CPP-115 with GABA-AT is about 2000, releasing cyclopentanone-2,4-dicarboxylate (22) and two other precursors of this compound (20 and 21). Time-dependent inactivation occurs by a conformational change induced by the formation of the aldimine of 4-aminocyclopentane-1,3-dicarboxylic acid and PMP (20), which disrupts an electrostatic interaction between Glu270 and Arg445 to form an electrostatic interaction between Arg445 and the newly formed carboxylate produced by hydrolysis of the difluoromethylene group in CPP-115, resulting in a noncovalent, tightly bound complex. Ultimately, this represents a novel mechanism for inactivation of GABA-AT and a new approach for the design of mechanism-based inactivators in general.« less

Higher gamma-aminobutyric acid neuron density in the white matter of orbital frontal cortex in schizophrenia.

PubMed

Joshi, Dipesh; Fung, Samantha J; Rothwell, Alice; Weickert, Cynthia Shannon

2012-11-01

In the orbitofrontal cortex (OFC), reduced gray matter volume and reduced glutamic acid decarboxylase 67kDa isoform (GAD67) messenger (m)RNA are found in schizophrenia; however, how these alterations relate to developmental pathology of interneurons is unclear. The present study therefore aimed to determine if increased interstitial white matter neuron (IWMN) density exists in the OFC; whether gamma-aminobutyric acid (GABA)ergic neuron density in OFC white matter was altered; and how IWMN density may be related to an early-expressed inhibitory neuron marker, Dlx1, in OFC gray matter in schizophrenia. IWMN densities were determined (38 schizophrenia and 38 control subjects) for neuronal nuclear antigen (NeuN+) and 65/67 kDa isoform of glutamic acid decarboxylase immunopositive (GAD65/67+) neurons. In situ hybridization was performed to determine Dlx1 and GAD67 mRNA expression in the OFC gray matter. NeuN and GAD65/67 immunopositive cell density was significantly increased in the superficial white matter in schizophrenia. Gray matter Dlx1 and GAD67 mRNA expression were reduced in schizophrenia. Dlx1 mRNA levels were negatively correlated with GAD65/67 IWMN density. Our study provides evidence that pathology of IWMNs in schizophrenia includes GABAergic interneurons and that increased IWMN density may be related to GABAergic deficits in the overlying gray matter. These findings provide evidence at the cellular level that the OFC is a site of pathology in schizophrenia and support the hypothesis that inappropriate migration of cortical inhibitory interneurons occurs in schizophrenia. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Novel fermented chickpea milk with enhanced level of γ-aminobutyric acid and neuroprotective effect on PC12 cells.

PubMed

Li, Wen; Wei, Mingming; Wu, Junjun; Rui, Xin; Dong, Mingsheng

2016-01-01

In this study, novel fermented chickpea milk with high γ -aminobutyric acid (GABA) content and potential neuroprotective activity was developed. Fermentation starter that can produce GABA was selected from 377 strains of lactic acid bacteria isolated from traditional Chinese fermented foods. Among the screened strains, strain M-6 showed the highest GABA-producing capacity in De Man-Rogosa and Sharp (MRS) broth and chickpea milk. M-6 was identified as Lactobacillus plantarum based on Gram staining, API carbohydrate fermentation pattern testing, and 16s rDNA sequencing. The complete gene encoding glutamate decarboxylase was cloned to confirm the presence of the gene in L. plantarum M-6. The fermentation condition was optimized by response surface methodology. Results demonstrated that L. plantarum M-6 produced the highest GABA content of 537.23 mg/L. The optimal condition included an inoculum concentration of 7%, presence of 0.2% (m/v) monosodium glutamate and 55 µ M pyridoxal-5-phosphate, incubation temperature of 39 °C and fermentation time of 48 h . GABA-enriched chickpea milk exerted protective effects on PC12 cells against MnCl2 -induced injury. GABA-enriched chickpea milk improved cell viability and markedly attenuated the release of lactate dehydrogenase compared with the impaired cells.

Effect of dietary γ-aminobutyric acid on laying performance, egg quality, immune activity and endocrine hormone in heat-stressed Roman hens.

PubMed

Zhang, Min; Zou, Xiao-Ting; Li, Hui; Dong, Xin-Yang; Zhao, Wenjing

2012-02-01

This study was conducted to evaluate the effect of γ-aminobutyric acid (GABA) on laying performance, egg quality, digestive enzyme activity, hormone level and immune activities in Roman hens under heat stress. Roman hens (320 days old) were fed with 0, 25, 50, 75 and 100 mg/kg GABA, respectively during a 60-day experiment. Compared with control, supplementation of 50 mg/kg GABA improved the laying performance and egg quality by significantly increasing egg production, average egg weight and shell strength (P < 0.05), while decreasing the feed-egg ratio and cholesterol level. Anti-oxidation activity was improved by significantly increasing the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), but decreasing malondialdehyde level in serum (P < 0.05), while significantly increasing the glucose and total protein (TP) level, follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E(2) ), insulin, triiodothyronine (T(3) ) and free triiodothyronine (FT(3) ) levels, and IgG, IgA and complement (C3)activity in serum (P < 0.05). The results indicated that oral GABA improved laying performance and physical condition mainly by modulating hormone secretion, enhancing anti-oxidation and immune activity, and maintaining electrolyte balance. Fifty mg/kg was the optimum level for laying hens under heat stress in the present study. © 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

Nonproteinogenic D-amino acids at millimolar concentrations are a toxin for anaerobic microorganisms relevant to early Earth and other anoxic planets.

PubMed

Nixon, Sophie L; Cockell, Charles S

2015-03-01

The delivery of extraterrestrial organics to early Earth provided a potentially important source of carbon and energy for microbial life. Optically active organic compounds of extraterrestrial origin exist in racemic form, yet life on Earth has almost exclusively selected for L- over D-enantiomers of amino acids. Although D-enantiomers of proteinogenic amino acids are known to inhibit aerobic microorganisms, the role of concentrated nonproteinogenic meteoritic D-amino acids on anaerobic metabolisms relevant to early Earth and other anoxic planets such as Mars is unknown. Here, we test the inhibitory effect of D-enantiomers of two nonproteinogenic amino acids common to carbonaceous chondrites, norvaline and α-aminobutyric acid, on microbial iron reduction. Three pure strains (Geobacter bemidjiensis, Geobacter metallireducens, Geopsychrobacter electrodiphilus) and an iron-reducing enrichment culture were grown in the presence of 10 mM D-enantiomers of both amino acids. Further tests were conducted to assess the inhibitory effect of these D-amino acids at 1 and 0.1 mM. The presence of 10 mM D-norvaline and D-α-aminobutyric acid inhibited microbial iron reduction by all pure strains and the enrichment. G. bemidjiensis was not inhibited by either amino acid at 0.1 mM, but D-α-aminobutyric acid still inhibited at 1 mM. Calculations using published meteorite accumulation rates to the martian surface indicate D-α-aminobutyric acid may have reached inhibitory concentrations in little over 1000 years during peak infall. These data show that, on a young anoxic planet, the use of one enantiomer over another may render the nonbiological enantiomer an environmental toxin. Processes that generate racemic amino acids in the environment, such as meteoritic infall or impact synthesis, would have been toxic processes and could have been a selection pressure for the evolution of early racemases.

Gamma-Aminobutyric acid and benzodiazepine receptors in the kindling model of epilepsy: a quantitative radiohistochemical study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, C.; Pedersen, H.B.; McNamara, J.O.

1985-10-01

Quantitative radiohistochemistry was utilized to study alterations of gamma-aminobutyric acid (GABA) and benzodiazepine receptors in the kindling model of epilepsy. The radioligands used for GABA and benzodiazepine receptors were (TH) muscimol and (TH)flunitrazepam, respectively. GABA receptor binding was increased by 22% in fascia dentata of the hippocampal formation but not in neocortex or substantia nigra of kindled rats. Within fascia dentata, GABA receptor binding was increased to an equivalent extent in stratum granulosum and throughout stratum moleculare; no increase was found in dentate hilus or stratum lacunosummoleculare or stratum radiatum of CA1. The increased binding was present at 24 hrmore » but not at 28 days after the last kindled seizure. The direction, anatomic distribution, and time course of the increased GABA receptor binding were paralleled by increased benzodiazepine receptor binding. The anatomic distribution of the increased GABA receptor binding is consistent with a localization to somata and dendritic trees of dentate granule cells. The authors suggest that increased GABA and benzodiazepine receptor binding may contribute to enhanced inhibition of dentate granule cells demonstrated electrophysiologically in kindled animals.« less

Comparison of the density of gamma-aminobutyric acid in the ventromedial prefrontal cortex of patients with first-episode psychosis and healthy controls.

PubMed

Yang, Zhilei; Zhu, Yajing; Song, Zhenhua; Mei, Li; Zhang, Jianye; Chen, Tianyi; Wang, Yingchan; Xu, Yifeng; Jiang, Kaida; Li, Yao; Liu, Dengtang

2015-12-25

Abnormality in the concentration and functioning of gamma-aminobutyric acid (γ-aminobutyric acid, GABA) in the brain is not only an important hypothetical link to the cause of schizophrenia but it may also be correlated with the cognitive decline and negative symptoms of schizophrenia. Studies utilizing high field magnetic resonance spectroscopy (MRS) report abnormal density of GABA in the ventromedial prefrontal cortex (vmPFC) of patients with chronic schizophrenia, but these results may be confounded by study participants' prior use of antipsychotic medications. Compare the density of GABA in the vmPFC of patients with first-episode psychosis to that in healthy controls and assess the relationship of GABA density in the vmPFC to the severity of psychotic symptoms. Single-voxel (1)H-MRS was used to assess the concentration of GABA and other metabolites in the vmPFC of 22 patients with first-episode psychosis (10 with schizophrenia and 12 with schizophreniform disorder) and 23 healthy controls. Thirteen of the 22 patients were drug-naïve and 9 had used antipsychotic medication for less than 3 days. The Positive and Negative Syndrome Scale (PANSS) was used to evaluate the severity of psychotic symptoms in the patient group. The mean (sd) GABA density in the vmPFC was significantly higher in patients than in controls (2.28 [0.54] v. 1.93 [0.32] mM, t=2.62, p=0.012). The densities of other metabolites - including N-acetylaspartic acid (NAA), glutamic acid (GLU), and glutamine (GLN) - were not significantly different between patients and controls. Among the patients, GABA density in the vmPFC was not significantly correlated with PANSS total score or with any of the three PANSS subscale scores for positive symptoms, negative symptoms, and general psychopathology. GABA concentration was not associated with the duration of illness, but it was significantly correlated with patient age (r=0.47, p=0.026). Elevation of GABA density in the vmPFC of patients with first

Enhancement of gamma-aminobutyric acid (GABA) levels using an autochthonous Lactobacillus futsaii CS3 as starter culture in Thai fermented shrimp (Kung-Som).

PubMed

Sanchart, Chatthaphisuth; Rattanaporn, Onnicha; Haltrich, Dietmar; Phukpattaranont, Pimpimol; Maneerat, Suppasil

2017-08-01

Gamma-aminobutyric acid (GABA) is a non-proteinogenic amino acid, which has a variety of well-characterized beneficial physiological functions. In order to improve GABA levels and the fermentation process of Thai fermented shrimp (Kung-Som), autochthonous Lactobacillus futsaii CS3 was inoculated as a starter culture into Kung-Som, and its effects on the quality of Kung-Som were studied. The optimal conditions for GABA production in Kung-Som as obtained by response surface methodology (RSM) using a central composite design (CCD) were an inoculum size of roughly 10 7 CFU/g (X 1 ) of L. futsaii cells together with the addition of 0.5% (w/w) monosodium glutamate (MSG) (X 2 ), resulting in maximum GABA levels of 10,500 mg per kg fresh product. Under these optimized conditions, the experimental GABA content of Kung-Som with an added starter culture was up to four times higher than that of the control (without starter culture) or commercial Kung-Som products (10,120 mg/kg product). Kung-Som produced by inoculation with L. futsaii CS3 but without addition of MSG showed a considerably increased GABA content of 7790 mg/kg compared to the control. Fermentation time was reduced to less than 1 week for these samples compared to the control batches, which took up to 19 days. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) revealed that L. futsaii CS3 remained prominently throughout the Kung-Som fermentation, and that lactic acid bacteria (LAB) rapidly dominated the total microflora because of this inoculation with L. futsaii CS3. Kung-Som samples with starter culture were accepted as well as commercial ones by 30 panelists (p > 0.05). In conclusion, L. futsaii CS3 is a good starter culture for GABA production, resulting in, improved microbiological safety as well as reduced fermentation time.

β-aminobutyric acid mediated drought stress alleviation in maize (Zea mays L.).

PubMed

Shaw, Arun K; Bhardwaj, Pardeep K; Ghosh, Supriya; Roy, Sankhajit; Saha, Suman; Sherpa, Ang R; Saha, Samir K; Hossain, Zahed

2016-02-01

The present study highlights the role of β-aminobutyric acid (BABA) in alleviating drought stress effects in maize (Zea mays L.). Chemical priming was imposed by pretreating 1-week-old plants with 600 μM BABA prior to applying drought stress. Specific activities of key antioxidant enzymes and metabolites (ascorbate and glutathione) levels of ascorbate-glutathione cycle were studied to unravel the priming-induced modulation of plant defense system. Furthermore, changes in endogenous ABA and JA concentrations as well as mRNA expressions of key genes involved in their respective biosynthesis pathways were monitored in BABA-primed (BABA+) and non-primed (BABA-) leaves of drought-challenged plants to better understand the mechanistic insights into the BABA-induced hormonal regulation of plant response to water-deficit stress. Accelerated stomatal closure, high relative water content, and less membrane damage were observed in BABA-primed leaves under water-deficit condition. Elevated APX and SOD activity in non-primed leaves found to be insufficient to scavenge all H2O2 and O2 (·-) resulting in oxidative burst as evident after histochemical staining with NBT and DAB. A higher proline accumulation in non-primed leaves also does not give much protection against drought stress. Increased GR activity supported with the enhanced mRNA and protein expressions might help the BABA-primed plants to maintain a high GSH pool essential for sustaining balanced redox status to counter drought-induced oxidative stress damages. Hormonal analysis suggests that in maize, BABA-potentiated drought tolerance is primarily mediated through JA-dependent pathway by the activation of antioxidant defense systems while ABA biosynthesis pathway also plays an important role in fine-tuning of drought stress response.

Lactobacillus brevis G101 inhibits the absorption of monosodium glutamate in mice.

PubMed

Jang, Se-Eun; Han, Myung Joo; Kim, Se-Young; Kim, Dong-Hyun

2014-11-28

To evaluate the effect of Lactobacillus brevis G-101 on absorption of monosodium glutamate (MSG), we orally administered MSG with or without G-101 in mice and measured the maximum concentration (Cmax) and blood concentration curve (AUC) of MSG and γ- aminobutyric acid (GABA). Oral administration of G-101 (1 × 10(9) CFU/mouse) potently inhibited Cmax and AUC of MSG by 97.8% and 94.3%, respectively (p < 0.05), but increased those of GABA by 32.1% and 67.7%, respectively (p < 0.05). G-101 inhibited the absorption of MSG. These results suggest that G-101 may reduce the side effect of MSG by inhibiting the absorption of MSG.

Impact of Precooling and Controlled-Atmosphere Storage on γ-Aminobutyric Acid (GABA) Accumulation in Longan (Dimocarpus longan Lour.) Fruit.

PubMed

Zhou, Molin; Ndeurumio, Kessy H; Zhao, Lei; Hu, Zhuoyan

2016-08-24

Longan (Dimocarpus longan Lour.) fruit cultivars 'Chuliang' and 'Shixia' were analyzed for γ-aminobutyric acid (GABA) accumulation after precooling and in controlled-atmosphere storage. Fruit were exposed to 5% O2 plus 3%, 5%, or 10% CO2 at 4 °C, and GABA and associated enzymes, aril firmness, and pericarp color were measured. Aril softening and pericarp browning were delayed by 5% CO2 + 5% O2. GABA concentrations and glutamate decarboxylase (GAD; EC 4.1.1.15) activities declined during storage at the higher-CO2 treatments. However, GABA aminotransferase (GABA-T; EC 2.6.1.19) activities in elevated CO2-treated fruit fluctuated during storage. GABA concentrations increased after precooling treatments. GAD activity and GABA-T activity were different between cultivars after precooling. GABA concentrations in fruit increased after 3 days of 10% CO2 + 5% O2 treatment and then declined as storage time increased. GABA accumulation was associated with stimulation of GAD activity rather than inhibition of GABA-T activity.

A ketogenic diet modifies glutamate, gamma-aminobutyric acid and agmatine levels in the hippocampus of rats: A microdialysis study.

PubMed

Calderón, Naima; Betancourt, Luis; Hernández, Luis; Rada, Pedro

2017-03-06

The ketogenic diet (KD) is acknowledged as an unconventional option in the treatment of epilepsy. Several lines of investigation point to a possible role of glutamate and gamma-aminobutyric acid (GABA) as main contributors in this protective effect. Other biomolecules could also be involved in the beneficial consequence of the KD, for example, the diamine agmatine has been suggested to block imidazole and glutamate NMDA receptor and serves as an endogenous anticonvulsant in different animal models of epilepsy. In the present report, we have used microdialysis coupled to capillary electrophoresis to monitor microdialysate levels of GABA, glutamate and agmatine in the hippocampus of rats submitted to a KD for 15days compared to rats on a normal rat chow diet. A significant increase in GABA and agmatine levels while no change in glutamate levels was observed. These results support the notion that the KD modifies different transmitters favoring inhibitory over excitatory neurotransmitters. Copyright © 2017 Elsevier B.V. All rights reserved.

Induced resistance in tomato fruit by γ-aminobutyric acid for the control of alternaria rot caused by Alternaria alternata.

PubMed

Yang, Jiali; Sun, Cui; Zhang, Yangyang; Fu, Da; Zheng, Xiaodong; Yu, Ting

2017-04-15

The study investigated the effect of γ-aminobutyric acid (GABA) on the control of alternaria rot in tomato fruit and the possible mechanism involved. Our results showed exogenous GABA could stimulate remarkable resistance to the alternaria rot, while it had no direct antifungal activity against Alternaria alternata. Moreover, the activities of antioxidant enzymes, including peroxidase, superoxide dismutase and catalase, along with the expression of these corresponding genes, were significantly induced in the GABA treatment. The obtained data suggested GABA induced resistance against the necrotrophic pathogen A. alternata, at least in part by activating antioxidant enzymes, restricting the levels of cell death caused by reactive oxygen species. Meanwhile, the key enzyme genes of GABA shunt, GABA transaminase and succinic-semialdehyde dehydrogenase, were found up-regulated in the GABA treatment. The activation of the GABA shunt might play a vital role in the resistance mechanism underpinning GABA-induced plant immunity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous detection of resolved glutamate, glutamine, and γ-aminobutyric acid at 4 T

NASA Astrophysics Data System (ADS)

Hu, Jiani; Yang, Shaolin; Xuan, Yang; Jiang, Quan; Yang, Yihong; Haacke, E. Mark

2007-04-01

A new approach is introduced to simultaneously detect resolved glutamate (Glu), glutamine (Gln), and γ-aminobutyric acid (GABA) using a standard STEAM localization pulse sequence with the optimized sequence timing parameters. This approach exploits the dependence of the STEAM spectra of the strongly coupled spin systems of Glu, Gln, and GABA on the echo time TE and the mixing time TM at 4 T to find an optimized sequence parameter set, i.e., {TE, TM}, where the outer-wings of the Glu C4 multiplet resonances around 2.35 ppm, the Gln C4 multiplet resonances around 2.45 ppm, and the GABA C2 multiplet resonance around 2.28 ppm are significantly suppressed and the three resonances become virtual singlets simultaneously and thus resolved. Spectral simulation and optimization were conducted to find the optimized sequence parameters, and phantom and in vivo experiments (on normal human brains, one patient with traumatic brain injury, and one patient with brain tumor) were carried out for verification. The results have demonstrated that the Gln, Glu, and GABA signals at 2.2-2.5 ppm can be well resolved using a standard STEAM sequence with the optimized sequence timing parameters around {82 ms, 48 ms} at 4 T, while the other main metabolites, such as N-acetyl aspartate (NAA), choline (tCho), and creatine (tCr), are still preserved in the same spectrum. The technique can be easily implemented and should prove to be a useful tool for the basic and clinical studies associated with metabolism of Glu, Gln, and/or GABA.

Frontal Gamma-Aminobutyric Acid Concentrations Are Associated With Cognitive Performance in Older Adults.

PubMed

Porges, Eric C; Woods, Adam J; Edden, Richard A E; Puts, Nicolaas A J; Harris, Ashley D; Chen, Huaihou; Garcia, Amanda M; Seider, Talia R; Lamb, Damon G; Williamson, John B; Cohen, Ronald A

2017-01-01

Gamma-aminobutyric acid (GABA), the brain's principal inhibitory neurotransmitter, has been associated with perceptual and attentional functioning. Recent application of magnetic resonance spectroscopy (MRS) provides in vivo evidence for decreasing GABA concentrations during adulthood. It is unclear, however, how age-related decrements in cerebral GABA concentrations contribute to cognitive decline, or whether previously reported declines in cerebral GABA concentrations persist during healthy aging. We hypothesized that participants with higher GABA concentrations in the frontal cortex would exhibit superior cognitive function and that previously reported age-related decreases in cortical GABA concentrations continue into old age. We measured GABA concentrations in frontal and posterior midline cerebral regions using a Mescher-Garwood point-resolved spectroscopy (MEGA-PRESS) 1 H-MRS approach in 94 older adults without history or clinical evidence of mild cognitive impairment or dementia (mean age, 73 years). We administered the Montreal Cognitive Assessment to assess cognitive functioning. Greater frontal GABA concentrations were associated with superior cognitive performance. This relation remained significant after controlling for age, years of education, and brain atrophy. GABA concentrations in both frontal and posterior regions decreased as a function of age. These novel findings from a large, healthy, older population indicate that cognitive function is sensitive to cerebral GABA concentrations in the frontal cortex, and GABA concentration in frontal and posterior regions continue to decline in later age. These effects suggest that proton MRS may provide a clinically useful method for the assessment of normal and abnormal age-related cognitive changes and the associated physiological contributors.

gamma-Aminobutyric acid-activated chloride channels: relationship to genetic differences in ethanol sensitivity.

PubMed

Allan, A M; Spuhler, K P; Harris, R A

1988-03-01

We demonstrated recently that low concentrations of ethanol enhanced the muscimol-stimulated chloride influx in cerebellar membranes from long sleep (LS-ethanol sensitive) mice, but had no effect on membranes from short sleep (SS-ethanol resistant) mice. The LS and SS were selected from a heterogeneous stock (HS) of mice for differential sensitivity to the hypnotic effects of ethanol as measured by the duration of the loss of the righting reflex (sleep time). In the present study, we tested 100 HS for ethanol sleep time. The mice with the shortest sleep time (HS-SS) and the mice with the longest sleep time (HS-LS) were selected and tested for the effect of ethanol and muscimol on chloride flux in cerebellum. The effects of ethanol and muscimol on both cerebellar and cortical chloride flux were also examined in rats from the 7th generation selected for differential sensitivity to the hypnotic effects of ethanol (high acute ethanol sensitive rats-HAS and low acute ethanol sensitive rats-LAS). Low concentrations of ethanol (10-30 mM) potentiated muscimol stimulation of 36Cl- uptake in both cortical and cerebellar membranes prepared from ethanol-sensitive animals (HS-LS and HAS). None of the ethanol concentrations tested altered stimulated chloride uptake in ethanol-resistant animals (HS-SS and LAS). No differences in muscimol stimulation of chloride uptake were observed between the pairs of selected lines. These findings strongly suggest that genetic differences in ethanol hypnosis are related to differences in the sensitivity of gamma-aminobutyric acid-operated chloride channels to ethanol.

Frontal Gamma-Aminobutyric Acid Concentrations Are Associated With Cognitive Performance in Older Adults

PubMed Central

Porges, Eric C.; Woods, Adam J.; Edden, Richard A.E.; Puts, Nicolaas A.J.; Harris, Ashley D.; Chen, Huaihou; Garcia, Amanda M.; Seider, Talia R.; Lamb, Damon G.; Williamson, John B.; Cohen, Ronald A.

2017-01-01

BACKGROUND Gamma-aminobutyric acid (GABA), the brain’s principal inhibitory neurotransmitter, has been associated with perceptual and attentional functioning. Recent application of magnetic resonance spectroscopy (MRS) provides in vivo evidence for decreasing GABA concentrations during adulthood. It is unclear, however, how age-related decrements in cerebral GABA concentrations contribute to cognitive decline, or whether previously reported declines in cerebral GABA concentrations persist during healthy aging. We hypothesized that participants with higher GABA concentrations in the frontal cortex would exhibit superior cognitive function and that previously reported age-related decreases in cortical GABA concentrations continue into old age. METHODS We measured GABA concentrations in frontal and posterior midline cerebral regions using a Mescher-Garwood point-resolved spectroscopy (MEGA-PRESS) 1H-MRS approach in 94 older adults without history or clinical evidence of mild cognitive impairment or dementia (mean age, 73 years). We administered the Montreal Cognitive Assessment to assess cognitive functioning. RESULTS Greater frontal GABA concentrations were associated with superior cognitive performance. This relation remained significant after controlling for age, years of education, and brain atrophy. GABA concentrations in both frontal and posterior regions decreased as a function of age. CONCLUSIONS These novel findings from a large, healthy, older population indicate that cognitive function is sensitive to cerebral GABA concentrations in the frontal cortex, and GABA concentration in frontal and posterior regions continue to decline in later age. These effects suggest that proton MRS may provide a clinically useful method for the assessment of normal and abnormal age-related cognitive changes and the associated physiological contributors. PMID:28217759

Brain infection with Staphylococcus aureus leads to high extracellular levels of glutamate, aspartate, γ-aminobutyric acid, and zinc.

PubMed

Hassel, Bjørnar; Dahlberg, Daniel; Mariussen, Espen; Goverud, Ingeborg Løstegaard; Antal, Ellen-Ann; Tønjum, Tone; Maehlen, Jan

2014-12-01

Staphylococcal brain infections may cause mental deterioration and epileptic seizures, suggesting interference with normal neurotransmission in the brain. We injected Staphylococcus aureus into rat striatum and found an initial 76% reduction in the extracellular level of glutamate as detected by microdialysis at 2 hr after staphylococcal infection. At 8 hr after staphylococcal infection, however, the extracellular level of glutamate had increased 12-fold, and at 20 hr it had increased >30-fold. The extracellular level of aspartate and γ-aminobutyric acid (GABA) also increased greatly. Extracellular Zn(2+) , which was estimated at ∼2.6 µmol/liter in the control situation, was increased by 330% 1-2.5 hr after staphylococcal infection and by 100% at 8 and 20 hr. The increase in extracellular glutamate, aspartate, and GABA appeared to reflect the degree of tissue damage. The area of tissue damage greatly exceeded the area of staphylococcal infiltration, pointing to soluble factors being responsible for cell death. However, the N-methyl-D-aspartate receptor antagonist MK-801 ameliorated neither tissue damage nor the increase in extracellular neuroactive amino acids, suggesting the presence of neurotoxic factors other than glutamate and aspartate. In vitro staphylococci incubated with glutamine and glucose formed glutamate, so bacteria could be an additional source of infection-related glutamate. We conclude that the dramatic increase in the extracellular concentration of neuroactive amino acids and zinc could interfere with neurotransmission in the surrounding brain tissue, contributing to mental deterioration and a predisposition to epileptic seizures, which are often seen in brain abscess patients. © 2014 Wiley Periodicals, Inc.

Accumulation mechanism of γ-aminobutyric acid in tomatoes (Solanum lycopersicum L.) under low O2 with and without CO2.

PubMed

Mae, Nobukazu; Makino, Yoshio; Oshita, Seiichi; Kawagoe, Yoshinori; Tanaka, Atsushi; Aoki, Koh; Kurabayashi, Atsushi; Akihiro, Takashi; Akama, Kazuhito; Koike, Satoshi; Takayama, Mariko; Matsukura, Chiaki; Ezura, Hiroshi

2012-02-01

The storage of ripe tomatoes in low-O(2) conditions with and without CO(2) promotes γ-aminobutyric acid (GABA) accumulation. The activities of glutamate decarboxylase (GAD) and α-ketoglutarate-dependent GABA transaminase (GABA-TK) were higher and lower, respectively, following storage under hypoxic (2.4 or 3.5% O(2)) or adjusted aerobic (11% O(2)) conditions compared to the activities in air for 7 days at 25 °C. GAD activity was consistent with the expression level of mRNA for GAD. The GABA concentration in tomatoes stored under hypoxic conditions and adjusted aerobic conditions was 60-90% higher than that when they are stored in air on the same day. These results demonstrate that upregulation of GAD activity and downregulation of GABA-TK activity cause GABA accumulation in tomatoes stored under low-O(2) conditions. Meanwhile, the effect of CO(2) on GABA accumulation is probably minimal.

Effect of thiopental sodium on the release of glutamate and gamma-aminobutyric acid from rats prefrontal cortical synaptosomes.

PubMed

Liu, Hongliang; Yao, Shanglong

2004-01-01

To investigate the effect of thiopental sodium on the release of glutamate and gamma-aminobutyric acid (GABA) from synaptosomes in the prefrontal cortex, synaptosomes were made, the spontaneous release and the evoked release by 30 mmol/L KCl or 20 micromol/L veratridine of glutamate and GABA were performed under various concentrations of thiopental sodium (10-300 micromol/L), glutamate and GABA concentrations were determined by reversed-phase high-performance liquid chromatography. Our results showed that spontaneous release and evoked release of glutamate were significantly inhibited by 30 micromol/L, 100 micromol/L and 300 micromol/L thiopental sodium, IC50 of thiopental sodium was 25.8 +/- 2.3 micromol/L for the spontaneous release, 23.4 +/- 2.4 micromol/L for KCl-evoked release, and 24.3 +/- 1.8 micromol/L for veratridine-evoked release. But GABA spontaneous release and evoked release were unaffected. The study showed that thiopental sodium with clinically related concentrations could inhibit the release of glutamate, but had no effect on the release of GABA from rats prefrontal cortical synaptosomes.

Renoprotective effects of gamma-aminobutyric acid on cisplatin-induced acute renal injury in rats.

PubMed

Ali, Badreldin H; Al-Salam, Suhail; Al Za'abi, Mohammed; Al Balushi, Khalid A; AlMahruqi, Ahmed S; Beegam, Somyia; Al-Lawatia, Intisar; Waly, Mostafa I; Nemmar, Abderrahim

2015-01-01

To investigate the effect of gamma-aminobutyric acid (GABA) on acute renal injury (ARI), we used here a rat model of acute tubular necrosis induced by the anticancer drug cisplatin (CP). GABA was given orally (100 or 500 mg/kg/day for ten consecutive days), and on the 6th day, some of the treated rats were also injected intraperitoneally with either saline or CP (6 mg/kg). Four days after CP treatment, urine was collected from all rats, which were then anaesthetized for blood pressure and renal blood flow monitoring. This was followed by intravenous injection of norepinephrine for the assessment of renal vasoconstrictor responses. Thereafter, blood and kidneys were collected for measurement of several functional, biochemical and structural parameters. GABA treatment (at 500 but not 100 mg/kg) significantly mitigated all the measured physiological and biochemical indices. Sections from saline- and GABA-treated rats showed apparently normal proximal tubules. However, kidneys of CP-treated rats had a moderate degree of necrosis. This was markedly lessened when CP was given simultaneously with GABA (500 mg/kg). The concentration of platinum in the cortical tissues was not significantly altered by GABA treatment. The results suggested that GABA can ameliorate CP nephrotoxicity in rats. Pending further pharmacological and toxicological studies, GABA may be considered a potentially useful nephroprotective agent in CP-induced ARI. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Effects of Frequency Drift on the Quantification of Gamma-Aminobutyric Acid Using MEGA-PRESS

NASA Astrophysics Data System (ADS)

Tsai, Shang-Yueh; Fang, Chun-Hao; Wu, Thai-Yu; Lin, Yi-Ru

2016-04-01

The MEGA-PRESS method is the most common method used to measure γ-aminobutyric acid (GABA) in the brain at 3T. It has been shown that the underestimation of the GABA signal due to B0 drift up to 1.22 Hz/min can be reduced by post-frequency alignment. In this study, we show that the underestimation of GABA can still occur even with post frequency alignment when the B0 drift is up to 3.93 Hz/min. The underestimation can be reduced by applying a frequency shift threshold. A total of 23 subjects were scanned twice to assess the short-term reproducibility, and 14 of them were scanned again after 2-8 weeks to evaluate the long-term reproducibility. A linear regression analysis of the quantified GABA versus the frequency shift showed a negative correlation (P < 0.01). Underestimation of the GABA signal was found. When a frequency shift threshold of 0.125 ppm (15.5 Hz or 1.79 Hz/min) was applied, the linear regression showed no statistically significant difference (P > 0.05). Therefore, a frequency shift threshold at 0.125 ppm (15.5 Hz) can be used to reduce underestimation during GABA quantification. For data with a B0 drift up to 3.93 Hz/min, the coefficients of variance of short-term and long-term reproducibility for the GABA quantification were less than 10% when the frequency threshold was applied.

A Cysteine Substitution Probes β3H267 Interactions with Propofol and Other Potent Anesthetics in α1β3γ2L Gamma-Aminobutyric Acid Type A Receptors

PubMed Central

Stern, Alex T.; Forman, Stuart A.

2015-01-01

Background Anesthetic contact residues in γ-aminobutyric acid type A (GABAA) receptors have been identified using photolabels, including two propofol derivatives. O-propofol-diazirine labels H267 in β3 and α1β3 receptors, while m-azi-propofol labels other residues in intersubunit clefts of α1β3. Neither label has been studied in αβγ receptors, the most common isoform in mammalian brain. In αβγ receptors, other anesthetic derivatives photolabel m-azi-propofol labeled residues, but not βH267. Our structural homology model of α1β3γ2L receptors suggests that β3H267 may abut some of these sites. Methods Substituted cysteine modification-protection was used to test β3H267C interactions with four potent anesthetics: propofol, etomidate, alphaxalone, and R-5-allyl-1-methyl-5-(m-trifluoromethyl-diazirinylphenyl) barbituric acid (mTFD-MPAB). We expressed α1β3γ2L or α1β3H267Cγ2L GABAA receptors in Xenopus oocytes. We used voltage clamp electrophysiology to assess receptor sensitivity to GABA and anesthetics, and to compare para-chloromercuribenzenesulfonate (pCMBS) modification rates with GABA versus GABA plus anesthetics. Results Enhancement of GABA EC5 responses by equi-hypnotic concentrations of all four anesthetics was similar in α1β3γ2L and α1β3H267Cγ2L receptors (n ≥ 3). Direct activation of α1β3H267Cγ2L receptors, but not α1β3γ2L, by mTFD-MPAB and propofol was significantly greater than the other anesthetics. Modification of β3H267C by pCMBS (n ≥ 4) was rapid and accelerated by GABA. Only mTFD-MPAB slowed β3H267C modification (~2-fold; p = 0.011). Conclusions β3H267 in α1β3γ2L GABAA receptors contacts mTFD-MPAB, but not propofol. Our results suggest that β3H267 is near the periphery of one or both transmembrane inter-subunit (α+/β− and γ+/β−) pockets where both mTFD-MPAB and propofol bind. PMID:26569173

Induced resistance against the Asian citrus psyllid, Diaphorina citri, by β-aminobutyric acid in citrus.

PubMed

Tiwari, Siddharth; Meyer, Wendy L; Stelinski, Lukasz L

2013-10-01

β-Aminobutyric acid (BABA) is known to induce resistance to microbial pathogens, nematodes and insects in several host plant/pest systems. The present study was undertaken to determine whether a similar effect of BABA occurred against the Asian citrus psyllid, Diaphorina citri Kuwayama, in citrus. A 25 mM drench application of BABA significantly reduced the number of eggs/plant as compared with a water control, whereas 200 and 100 mM applications of BABA reduced the numbers of nymphs/plant and adults/plants, respectively. A 5 mM foliar application of BABA significantly reduced the number of adults but not eggs or nymphs when compared with a water control treatment. In addition, leaf-dip bioassays using various concentrations (25–500 mM) of BABA indicated no direct toxic effect on 2nd and 5th instar nymphs or adult D. citri. BABA-treated plants were characterized by significantly lower levels of iron, magnesium, phosphorus, sodium, sulfur and zinc as compared with control plants. The expression level of the PR-2 gene (β-1,3-glucanase) in BABA-treated plants that were also damaged by D. citri adult feeding was significantly higher than in plants exposed to BABA, D. citri feeding alone or control plants. Our results indicate the potential for using BABA as a systemic acquired resistance management tool for D. citri.

J-difference-edited MRS measures of γ-aminobutyric acid before and after acute caffeine administration.

PubMed

Oeltzschner, Georg; Zöllner, Helge J; Jonuscheit, Marc; Lanzman, Rotem S; Schnitzler, Alfons; Wittsack, Hans-Jörg

2018-05-12

The aim of this study was to investigate potential effects of acute caffeine intake on J-difference-edited MRS measures of the primary inhibitory neurotransmitter γ-aminobutyric acid (GABA). J-difference-edited Mescher-Garwood PRESS (MEGA-PRESS) and conventional PRESS data were acquired at 3T from voxels in the anterior cingulate and occipital area of the brain in 15 healthy subjects, before and after oral intake of a 200-mg caffeine dose. MEGA-PRESS data were analyzed with the MATLAB-based Gannet tool to estimate GABA+ macromolecule (GABA+) levels, while PRESS data were analyzed with LCModel to estimate levels of glutamate, glutamate+glutamine, N-acetylaspartate, and myo-inositol. All metabolites were quantified with respect to the internal reference compounds creatine and tissue water, and compared between the pre- and post-caffeine intake condition. For both MRS voxels, mean GABA+ estimates did not differ before and after caffeine intake. Slightly lower estimates of myo-inositol were observed after caffeine intake in both voxels. N-acetylaspartate, glutamate, and glutamate+glutamine did not show significant differences between conditions. Mean GABA+ estimates from J-difference-edited MRS in two different brain regions are not altered by acute oral administration of caffeine. These findings may increase subject recruitment efficiency for MRS studies. © 2018 International Society for Magnetic Resonance in Medicine.

The association of plasma gamma-aminobutyric acid concentration with postoperative delirium in critically ill patients.

PubMed

Yoshitaka, Shiho; Egi, Moritoki; Kanazawa, Tomoyuki; Toda, Yuichiro; Morita, Kiyoshi

2014-12-01

Delirium is a common complication in postoperative, critically ill patients. The mechanism of postoperative delirium is not well understood but many studies have shown significant associations between benzodiazepine use, alcohol withdrawal and cirrhosis, and an increased risk of delirium. We aimed to investigate a possible link with alterations of gamma-aminobutyric acid (GABA) activity. A prospective observational investigation of 40 patients > 20 years old who had undergone elective surgery with general anaesthesia and were expected to need postoperative intensive care for more than 48 hours. We assessed postoperative delirium using the confusion assessment method in the intensive care unit at 1 hour after the operation and on postoperative Day (POD) 1 and POD 2. We collected blood samples for measurement of plasma GABA concentrations before the operation and on POD 1 and 2. Postoperative delirium and perioperative plasma GABA concentrations in patients with and without delirium. Postoperative delirium occurred in 13 of the patients. Patients with delirium had significantly higher Acute Physiology and Chronic Health Evaluation II scores than patients without delirium. The mean plasma GABA concentration on POD 2 was significantly lower in patients with delirium than in those without delirium. After adjustment of relevant variables, plasma GABA concentration on POD 2 was independently associated with postoperative delirium. Plasma GABA level on POD 2 has a significant independent association with postoperative delirium.

The Protective Effect of γ-aminobutyric Acid on Kidney Injury Induced by Renal Ischemia-reperfusion in Ovariectomized Estradiol-treated Rats.

PubMed

Talebi, Nahid; Nematbakhsh, Mehdi; Monajemi, Ramesh; Mazaheri, Safoora; Talebi, Ardeshir; Vafapour, Marzieh

2016-01-01

Renal ischemia-reperfusion injury (IRI) is one of the most important causes of kidney injury, which is possibly gender-related. This study was designed to investigate the role of γ-aminobutyric acid (GABA) against IRI in ovariectomized estradiol-treated rats. Thirty-five ovariectomized Wistar rats were used in six experimental groups. The first three groups did not subject to estradiol treatment and assigned as sham-operated, control, and GABA-treated groups. GABA (50 μmol/kg) and saline were injected in the treated and control groups 30 min before the surgery, respectively. The second three groups received the same treatments but received estradiol valerate (500 μg/kg, intramuscularly) 3 days prior to the surgery. The IRI was induced in the control and treated groups by clamping the renal artery for 45 min and then 24 h of reperfusion. All animals were sacrificed for the measurements. The serum levels of creatinine and blood urea nitrogen, kidney weight, and kidney tissue damage score significantly increased in the IRI rats (P < 0.05). GABA significantly decreased the aforementioned parameters (P < 0.05). The uterus weight increased significantly in rats that received estradiol (P < 0.05). Serum and kidney levels of nitrite (nitric oxide metabolite) did not alter significantly. Serum level of malondialdehyde increased significantly in the ovariectomized rats exposed to IRI (P < 0.05). It seems that GABA improved IRI in ovariectomized rats. Estradiol was also nephroprotective against IRI. However, co-administration of estradiol and GABA could not protect the kidney against IRI.

Oral intake of γ-aminobutyric acid affects mood and activities of central nervous system during stressed condition induced by mental tasks.

PubMed

Yoto, A; Murao, S; Motoki, M; Yokoyama, Y; Horie, N; Takeshima, K; Masuda, K; Kim, M; Yokogoshi, H

2012-09-01

γ-Aminobutyric acid (GABA) is a kind of amino acid contained in green tea leaves and other foods. Several reports have shown that GABA might affect brain protein synthesis, improve many brain functions such as memory and study capability, lower the blood pressure of spontaneously hypertensive rats, and may also have a relaxation effect in humans. However, the evidence for its mood-improving function is still not sufficient. In this study, we investigated how the oral intake of GABA influences human adults psychologically and physiologically under a condition of mental stress. Sixty-three adults (28 males, 35 females) participated in a randomized, single blind, placebo-controlled, crossover-designed study over two experiment days. Capsules containing 100 mg of GABA or dextrin as a placebo were used as test samples. The results showed that EEG activities including alpha band and beta band brain waves decreased depending on the mental stress task loads, and the condition of 30 min after GABA intake diminished this decrease compared with the placebo condition. That is to say, GABA might have alleviated the stress induced by the mental tasks. This effect also corresponded with the results of the POMS scores.

Guanidinoacetic acid loading affects plasma γ-aminobutyric acid in healthy men.

PubMed

Ostojic, Sergej M; Stojanovic, Marko

2015-08-01

Guanidinoacetic acid (GAA), a precursor of creatine and an innovative dietary agent, activates γ-amino butyric acid (GABA) receptors yet clinical effects of dietary GAA on GABA metabolism are currently unknown. The main aim of this pilot research was to investigate whether GAA loading affected peripheral GABA homeostasis in healthy humans. Eight healthy male volunteers aged 22-25 years were randomized in a double-blind design to receive either GAA (three grams daily) or placebo by oral administration for 3 weeks. At baseline and after 3 weeks participants provided fasting blood samples for free plasma levels of GABA, GAA, creatine and glutamine. Following 3 weeks of intervention, plasma GABA level dropped significantly in participants receiving 3 g of GAA per day as compared to the placebo (P = 0.03). GAA loading significantly decreased plasma GABA by 88.8 nmol/L (95% confidence interval; 5.4-172.1) after 3 weeks of intervention as compared to the baseline (P = 0.03). GAA intervention positively affected both plasma GAA and creatine (P < 0.05), while no effects of intervention were reported for plasma glutamine. Results indicate that supplemental GAA affects peripheral GABA metabolism, and potentially down-regulates GABA synthesis in peripheral tissues. Possible GABAergic action of dietary GAA adds to the safety profile of this novel dietary supplement.

Exogenous γ-aminobutyric Acid (GABA) Application Improved Early Growth, Net Photosynthesis, and Associated Physio-Biochemical Events in Maize.

PubMed

Li, Wu; Liu, Jianhua; Ashraf, Umair; Li, Gaoke; Li, Yuliang; Lu, Wenjia; Gao, Lei; Han, Fuguang; Hu, Jianguang

2016-01-01

γ-aminobutyric acid (GABA) is an endogenous signaling molecule and involved in growth regulations and plant development, however, a little information is available on the consequences of exogenous GABA application on growth, development, and associated physio-biochemical processes in maize. The present study examined the GABA-induced regulations in early growth, net photosynthetic rate, gas exchange, osmoregulation, and enzymatic activities in three maize cultivars, i.e., Yuecainuo 6, Zhengtian 68, and Yuecainuo 2. Two levels of GABA, i.e., 0 mg L(-1) and 50 mg L(-1), in solution form, with total application volume of 100 ml per pot containing 15 maize seedlings were exogenously applied. Results revealed that exogenous GABA application improved seedling growth in terms of seedling length and biomass accumulation in all maize cultivars at both 3 and 7 days after treatment (DAT). It also promoted net photosynthesis and variably affected gas exchange attributes, i.e., stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr), as well as leaves SPAD value. Furthermore, lipid peroxidation [in terms of malondialdehyde (MDA)] under GABA treated maize seedlings were also remained variable; however, osmolyte accumulation (protein and proline) and activities of anti-oxidants enzymes, i.e., super-oxide dismutase and peroxidase were also affected differently at both 3 and 7 DAT in all maize cultivars. Furthermore, enzymes involved in nitrogen metabolism, e.g., nitrate reductase and glutamine synthetase were improved. These results suggest the involvement of GABA in various physio-metablical mechanisms which might lead to improvement in morphological growth of maize. In future, research is still needed at molecular and genetic levels to unravel the involvement of GABA-mediated regulations in growth and its associated physio-biochemical mechanisms.

Wheat bran with enriched gamma-aminobutyric acid attenuates glucose intolerance and hyperinsulinemia induced by a high-fat diet.

PubMed

Shang, Wenting; Si, Xu; Zhou, Zhongkai; Strappe, Padraig; Blanchard, Chris

2018-05-23

In this study, the level of gamma-aminobutyric acid (GABA) in wheat bran was increased to be six times higher through the action of endogenous glutamate decarboxylase compared with untreated bran. The process of GABA formation in wheat bran also led to an increased level of phenolic compounds with enhanced antioxidant capacity 2 times higher than the untreated status. The interventional effect of a diet containing GABA-enriched bran on hyperinsulinemia induced by a high-fat diet (HFD) was investigated in a rat model. The results showed that, when compared with animals fed with HFD-containing untreated bran (NB group), the consumption of HFD-containing GABA-enriched bran (GB group) demonstrated a greater improvement of insulin resistance/sensitivity as revealed by the changes in the homeostatic model assessment for insulin resistance index (HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI). The expression of hepatic genes, cytochrome P450 family 7 subfamily A member 1 (Cyp7a1) and ubiquitin C (Ubc), which are involved in the adipogenesis-associated PPAR signalling pathway, was found to be significantly down-regulated in the GB group compared with the HFD group (P = 0.0055). Meanwhile, changes in the expression of a number of genes associated with lipid metabolism and gluconeogenesis were also noted in the GB group versus the HFD group, but not in the NB group, indicating different regulatory patterns between the two brans in a high-fat diet. More importantly, the analysis of key genes related to glucose metabolism further revealed that the expression of insulin-induced gene 1/2 (Insig-1/2) was increased following GB intervention with a corresponding reduction in phosphoenolpyruvate carboxykinase 1 (Pepck) and glucose-6-phosphatase, catalytic subunit (G6pc) expression, suggesting that glucose homeostasis is greatly improved through the intervention of GABA-enriched bran in the context of a high-fat diet.

Alterations of neurotransmitter norepinephrine and gamma-aminobutyric acid correlate with murine behavioral perturbations related to bisphenol A exposure.

PubMed

Ogi, Hiroshi; Itoh, Kyoko; Ikegaya, Hiroshi; Fushiki, Shinji

2015-09-01

Humans are commonly exposed to endocrine-disrupting chemical bisphenol A (BPA), giving rise to concern over the psychobehavioral effects of BPA. The aim of this study was to investigate the effects of prenatal and lactational BPA exposure on neurotransmitters, including norepinephrine (NE), gamma-aminobutyric acid (GABA) and glutamate (Glu), and to assess the association with behavioral phenotypes. C57BL/6J mice were orally administered with BPA (500 μg/bwkg/day) or vehicle daily from embryonic day 0 to postnatal week 3 (P3W), through their dams. The IntelliCage behavioral experiments were conducted from P11W to P15W. At around P14-16W, NE, GABA and Glu levels in nine brain regions were measured by high performance liquid chromatography. Furthermore, the associations between the neurotransmitter levels and the behavioral indices were statistically analyzed. In females exposed to BPA, the GABA and Glu levels in almost all regions, and the NE levels in the cortex, hypothalamus and thalamus were higher than those in the controls. In males exposed to BPA, the GABA levels in the amygdala and hippocampus showed lower values, while Glu levels were higher in some regions, compared with the controls. In regard to the associations, the number of "diurnal corner visits without drinking" was correlated with the NE levels in the cortex and thalamus in females. The "nocturnal corner visit duration without drinking" was correlated with the GABA level in the hippocampus in males. These results suggest that prenatal and lactational exposure to low doses of BPA might modulate the NE, GABA and Glu systems, resulting in behavioral alterations. Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Relationship among Glutamine, γ-Aminobutyric Acid, and Social Cognition in Autism Spectrum Disorders

PubMed Central

Sikoglu, Elif M.; Hodge, Steven M.; Edden, Richard A.E.; Foley, Ann; Kennedy, David N.; Moore, Constance M.; Frazier, Jean A.

2015-01-01

Abstract Objective: An imbalance of excitatory and inhibitory neurotransmission in autism spectrum disorder (ASD) has been proposed. We compared glutamate (Glu), glutamine (Gln), and γ-aminobutyric acid (GABA) levels in the anterior cingulate cortex (ACC) of 13 males with ASD and 14 typically developing (TD) males (ages 13–17), and correlated these levels with intelligence quotient (IQ) and measures of social cognition. Methods: Social cognition was evaluated by administration of the Social Responsiveness Scale (SRS) and the Reading the Mind in the Eyes Test (RMET). We acquired proton magnetic resonance spectroscopy (1H-MRS) data from the bilateral ACC using the single voxel point resolved spectroscopy sequence (PRESS) to quantify Glu and Gln, and Mescher–Garwood point-resolved spectroscopy sequence (MEGA-PRESS) to quantify GABA levels referenced to creatine (Cr). Results: There were higher Gln levels (p=0.04), and lower GABA/Cre levels (p=0.09) in the ASD group than in the TD group. There was no difference in Glu levels between groups. Gln was negatively correlated with RMET score (rho=−0.62, p=0.001) and IQ (rho=−0.56, p=0.003), and positively correlated with SRS scores (rho=0.53, p=0.007). GABA/Cre levels were positively correlated with RMET score (rho=0.34, p=0.09) and IQ (rho=0.36, p=0.07), and negatively correlated with SRS score (rho=−0.34, p=0.09). Conclusions: These data suggest an imbalance between glutamatergic neurotransmission and GABA-ergic neurotransmission in ASD. Higher Gln levels and lower GABA/Cre levels were associated with lower IQ and greater impairments in social cognition across groups. PMID:25919578

Enhancement of gama-aminobutyric acid (GABA) and other health-related metabolites in germinated red rice (Oryza sativa L.) by ultrasonication.

PubMed

Ding, Junzhou; Ulanov, Alexander V; Dong, Mengyi; Yang, Tewu; Nemzer, Boris V; Xiong, Shanbai; Zhao, Siming; Feng, Hao

2018-01-01

Red rice (Oryza sativa L.) that has a red (reddish brown) bran layer in de-hulled rice is known to contain rich biofunctional components. Germination is an effective technique to improve the nutritional quality, digestibility, and flavor of de-hulled rice. Ultrasonication, a form of physical stimulation, has been documented as a novel approach to improve the nutritional quality of plant-based food. This study was undertaken to test the use of ultrasound to enhance the nutritional value of red rice. Ultrasonication (5min, 16W/L) was applied to rice during soaking or after 66h germination. Changes of metabolites (amino acids, sugars, and organic acids) in red rice treated by ultrasonication were determined using a GC/MS plant primary metabolomics analysis platform. Differential expressed metabolites were identified through multivariate statistical analysis. Results showed that γ-aminobutyric acid (GABA) and riboflavin (vitamin B 2 ) in red rice significantly increased after germination for 72h, and then experienced a further increase after treatment by ultrasound at different stages during germination. The metabolomics analysis showed that some plant metabolites, i.e. GABA, O-phosphoethanolamine, and glucose-6-phosphate were significantly increased after the ultrasonic treatment (VIP>1.5) in comparison with the untreated germinated rice. The findings of this study showed that controlled germination with ultrasonic stress is an effective method to enhance GABA and other health-promoted components in de-hulled rice. Copyright © 2017 Elsevier B.V. All rights reserved.

Overexpression of Thioredoxin-1 Blocks Morphine-Induced Conditioned Place Preference Through Regulating the Interaction of γ-Aminobutyric Acid and Dopamine Systems.

PubMed

Li, Xiang; Huang, Mengbing; Yang, Lihua; Guo, Ningning; Yang, Xiaoyan; Zhang, Zhimin; Bai, Ming; Ge, Lu; Zhou, Xiaoshuang; Li, Ye; Bai, Jie

2018-01-01

Morphine is one kind of opioid, which is currently the most effective widely utilized pain relieving pharmaceutical. Long-term administration of morphine leads to dependence and addiction. Thioredoxin-1 (Trx-1) is an important redox regulating protein and works as a neurotrophic cofactor. Our previous study showed that geranylgeranylaceton, an inducer of Trx-1 protected mice from rewarding effects induced by morphine. However, whether overexpression of Trx-1 can block morphine-induced conditioned place preference (CPP) in mice is still unknown. In this study, we first examined whether overexpression of Trx-1 affects the CPP after morphine training and further examined the dopamine (DA) and γ-aminobutyric acid (GABA) systems involved in rewarding effects. Our results showed that morphine-induced CPP was blocked in Trx-1 overexpression transgenic (TG) mice. Trx-1 expression was induced by morphine in the ventral tegmental area (VTA) and nucleus accumbens (NAc) in wild-type (WT) mice, which was not induced in Trx-1 TG mice. The DA level and expressions of tyrosine hydroxylase (TH) and D1 were induced by morphine in WT mice, which were not induced in Trx-1 TG mice. The GABA level and expression of GABA B R were decreased by morphine, which were restored in Trx-1 TG mice. Therefore, Trx-1 may play a role in blocking CPP induced by morphine through regulating the expressions of D1, TH, and GABA B R in the VTA and NAc.

Ophthalmic acid is a marker of oxidative stress in plants as in animals.

PubMed

Servillo, Luigi; Castaldo, Domenico; Giovane, Alfonso; Casale, Rosario; D'Onofrio, Nunzia; Cautela, Domenico; Balestrieri, Maria Luisa

2018-04-01

Ophthalmic acid (OPH), γ-glutamyl-L-2-aminobutyryl-glycine, a tripeptide analogue of glutathione (GSH), has recently captured considerable attention as a biomarker of oxidative stress in animals. The OPH and GSH biosynthesis, as well as some biochemical behaviors, are very similar. Here, we sought to investigate the presence of OPH in plants and its possible relationship with GSH, known to possess multiple functions in the plant development, growth and response to environmental changes. HPLC-ESI-MS/MS analysis was used to examine the occurrence of OPH in leaves from various plant species, and flours from several plant seeds. Different types of oxidative stress, i.e., water, dark, paraquat, and cadmium stress, were induced in rye, barley, oat, and winter wheat leaves to evaluate the effects on the levels of OPH and its metabolic precursors. OPH and its dipeptide precursor, γ-glutamyl-2-aminobutyric acid, were found to occur in phylogenetically distant plants. Interestingly, the levels of OPH were tightly associated with the oxidative stress tested. Levels of OPH precursors, γ-glutamyl-2-aminobutyric acid and 2-aminobutyric acid, the latter efficiently formed in plants via biosynthetic pathways absent in the animal kingdom, were also found to increase during oxidative stress. OPH occurs in plants and its levels are tightly associated with oxidative stress. OPH behaves as an oxidative stress marker and its biogenesis might occur through a biochemical pathway common to many living organisms. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of Frequency Drift on the Quantification of Gamma-Aminobutyric Acid Using MEGA-PRESS

PubMed Central

Tsai, Shang-Yueh; Fang, Chun-Hao; Wu, Thai-Yu; Lin, Yi-Ru

2016-01-01

The MEGA-PRESS method is the most common method used to measure γ-aminobutyric acid (GABA) in the brain at 3T. It has been shown that the underestimation of the GABA signal due to B0 drift up to 1.22 Hz/min can be reduced by post-frequency alignment. In this study, we show that the underestimation of GABA can still occur even with post frequency alignment when the B0 drift is up to 3.93 Hz/min. The underestimation can be reduced by applying a frequency shift threshold. A total of 23 subjects were scanned twice to assess the short-term reproducibility, and 14 of them were scanned again after 2–8 weeks to evaluate the long-term reproducibility. A linear regression analysis of the quantified GABA versus the frequency shift showed a negative correlation (P < 0.01). Underestimation of the GABA signal was found. When a frequency shift threshold of 0.125 ppm (15.5 Hz or 1.79 Hz/min) was applied, the linear regression showed no statistically significant difference (P > 0.05). Therefore, a frequency shift threshold at 0.125 ppm (15.5 Hz) can be used to reduce underestimation during GABA quantification. For data with a B0 drift up to 3.93 Hz/min, the coefficients of variance of short-term and long-term reproducibility for the GABA quantification were less than 10% when the frequency threshold was applied. PMID:27079873

Affective and cognitive effects of global deletion of alpha3-containing gamma-aminobutyric acid-A receptors.

PubMed

Fiorelli, Roberto; Rudolph, Uwe; Straub, Carolin J; Feldon, Joram; Yee, Benjamin K

2008-09-01

Gamma-aminobutyric acid (GABA)A receptors characterized by the presence of the alpha3 subunit are the major GABAA receptor subtype expressed in brain stem monoaminergic nuclei. These alpha3-GABAA receptors are therefore in a unique position to regulate monoaminergic functions. To characterize the functional properties of alpha3-GABAA receptors, we present a preliminary assessment of the expression of affective and cognitive behaviour in male mice with a targeted deletion of the Gabra3 gene encoding the alpha3 subunit [alpha3 knockout (KO) mice] on a C57BL/6Jx129X1/SvJ F1 hybrid genetic background. The alpha3 KO mice did not exhibit any gross change of anxiety-like behaviour or spontaneous locomotor behaviour. In the Porsolt forced swim test for potential antidepressant activity, alpha3 KO mice exhibited reduced floating and enhanced swimming behaviour relative to wild-type controls. Performance on a two-choice sucrose preference test, however, revealed no evidence for an increase in sucrose preference in the alpha3 KO mice that would have substantiated a potential phenotype for depression-related behaviour. In contrast, a suggestion of an enhanced negative contrast effect was revealed in a one-bottle sucrose consumption test across different sucrose concentrations. These affective phenotypes were accompanied by alterations in the balance between conditioned responding to the discrete conditioned stimulus and to the context, and a suggestion of faster extinction, in the Pavlovian conditioned freezing paradigm. Spatial learning in the water maze reference memory test, however, was largely unchanged in the alpha3 KO mice, except for a trend of preservation during reversal learning. The novel phenotypes following global deletion of the GABAA receptor alpha3 subunit identified here provided relevant insights, in addition to our earlier study, into the potential behavioural relevance of this specific receptor subtypes in the modulation of both affective and cognitive

Axonal remodeling for motor recovery after traumatic brain injury requires downregulation of γ-aminobutyric acid signaling

PubMed Central

Lee, S; Ueno, M; Yamashita, T

2011-01-01

Remodeling of the remnant neuronal network after brain injury possibly mediates spontaneous functional recovery; however, the mechanisms inducing axonal remodeling during spontaneous recovery remain unclear. Here, we show that altered γ-aminobutyric acid (GABA) signaling is crucial for axonal remodeling of the contralesional cortex after traumatic brain injury. After injury to the sensorimotor cortex in mice, we found a significant decrease in the expression of GABAAR-α1 subunits in the intact sensorimotor cortex for 2 weeks. Motor functions, assessed by grid walk and cylinder tests, spontaneously improved in 4 weeks after the injury to the sensorimotor cortex. With motor recovery, corticospinal tract (CST) axons from the contralesional cortex sprouted into the denervated side of the cervical spinal cord at 2 and 4 weeks after the injury. To determine the functional implications of the changes in the expression of GABAAR-α1 subunits, we infused muscimol, a GABA R agonist, into the contralesional cortex for a week after the injury. Compared with the vehicle-treated mice, we noted significantly inhibited recovery in the muscimol-treated mice. Further, muscimol infusion greatly suppressed the axonal sprouting into the denervated side of the cervical spinal cord. In conclusion, recovery of motor function and axonal remodeling of the CST following cortical injury requires suppressed GABAAR subunit expression and decreased GABAergic signaling. PMID:21412279

Changes of tocopherols, tocotrienols, γ-oryzanol, and γ-aminobutyric acid levels in the germinated brown rice of pigmented and nonpigmented cultivars.

PubMed

Ng, Lean-Teik; Huang, Shao-Hua; Chen, Yen-Ting; Su, Chun-Han

2013-12-26

This study examined the changes of tocopherols (Toc), tocotrienols (T3), γ-oryzanol (GO), and γ-aminobutyric acid (GABA) contents in germinated brown rice (GBR) of pigmented and nonpigmented cultivars under different germination conditions. Results showed that the Toc and T3 contents in GBR were significantly different between treatments in both rice cultivars. The pigmented GBR possessed higher total vitamin E, total Toc, total T3, and GO contents than the nonpigmented GBR; however, its level of GABA was lower. The order of the three highest vitamin E homologues in pigmented and nonpigmented GBR was γ-T3 > γ-Toc > α-Toc and α-Toc > γ-T3 > α-T3, respectively; β-Toc, β-T3, δ-Toc, and δ-T3 were present in only small amounts (≤1.0 mg/kg) in GBR of both cultivars. Although both cultivars showed an increase in GABA contents with increasing germination time, the GABA content in nonpigmented GBR was higher.

β-Aminobutyric acid increases abscisic acid accumulation and desiccation tolerance and decreases water use but fails to improve grain yield in two spring wheat cultivars under soil drying.

PubMed

Du, Yan-Lei; Wang, Zhen-Yu; Fan, Jing-Wei; Turner, Neil C; Wang, Tao; Li, Feng-Min

2012-08-01

A pot experiment was conducted to investigate the effect of the non-protein amino acid, β-aminobutyric acid (BABA), on the homeostasis between reactive oxygen species (ROS) and antioxidant defence during progressive soil drying, and its relationship with the accumulation of abscisic acid (ABA), water use, grain yield, and desiccation tolerance in two spring wheat (Triticum aestivum L.) cultivars released in different decades and with different yields under drought. Drenching the soil with 100 µM BABA increased drought-induced ABA production, leading to a decrease in the lethal leaf water potential (Ψ) used to measure desiccation tolerance, decreased water use, and increased water use efficiency for grain (WUEG) under moderate water stress. In addition, at severe water stress levels, drenching the soil with BABA reduced ROS production, increased antioxidant enzyme activity, and reduced the oxidative damage to lipid membranes. The data suggest that the addition of BABA triggers ABA accumulation that acts as a non-hydraulic root signal, thereby closing stomata, and reducing water use at moderate stress levels, and also reduces the production of ROS and increases the antioxidant defence enzymes at severe stress levels, thus increasing the desiccation tolerance. However, BABA treatment had no effect on grain yield of wheat when water availability was limited. The results suggest that there are ways of effectively priming the pre-existing defence pathways, in addition to genetic means, to improve the desiccation tolerance and WUEG of wheat.

Substance P provoked gamma-aminobutyric acid release from the myenteric plexus of the guinea-pig small intestine.

PubMed Central

Tanaka, C; Taniyama, K

1985-01-01

The release of [3H]gamma-aminobutyric acid (GABA) from the isolated small intestine of the guinea-pig pre-loaded with [3H]GABA was measured in the presence of substance P and vasoactive intestinal polypeptide (VIP). Substance P (10(-10)-10(-7) M) produced a dose-dependent increase in the fractional rate of [3H]GABA release. VIP, even at 10(-7) M, did not affect the spontaneous [3H]GABA release nor the release of [3H]GABA evoked by electrical transmural stimulation (0.5 ms, 15 V, 10 Hz for 30 s). The release of endogenous GABA from the isolated small intestine was measured in the presence of substance P (10(-9) M). After 60 min superfusion, the spontaneous release of GABA was 4.61 +/- 0.14 pmol min-1 g-1 wet wt. (n = 20). Substance P (10(-9) M) produced an approximate 2-fold spontaneous release of endogeneous GABA (8.74 +/- 0.21 pmol min-1 g-1 wet wt. (n = 10)). Perfusion with Ca-free medium containing 1 mM-EGTA and tetrodotoxin (3 X 10(-7) M) inhibited the release of endogenous GABA evoked by substance P (10(-9) M). (D-Pro2, D-Trp7,9) substance P (10(-6) M) antagonized the release of endogenous GABA evoked by substance P (10(-9) M). These results indicate that substance P induces a neuronal release of GABA through its receptor located in the guinea-pig small intestine. Substance P (10(-11)-10(-7) M) produced a dose-dependent increase in the fractional rate of [3H]acetylcholine (ACh) release from the isolated small intestine pre-loaded with [3H]choline. The release of [3H]ACh evoked by substance P (10(-9) M) was inhibited by perfusion with Ca-free medium containing 1 mM-EGTA, tetrodotoxin (3 X 10(-7) M) and (D-Pro2, D-Trp7,9)substance P (10(-6) M). Bicuculline (10(-6) M) inhibited the release of [3H]ACh evoked by substance P (10(-9) M) by 68.1 +/- 4.6% (n = 5), thereby suggesting that the substance P-evoked ACh release is partly mediated through the endogenous GABA released by substance P. These results provide evidence for the neurotransmitter role of GABA and a

Short-term memory impairment after isoflurane in mice is prevented by the α5 γ-aminobutyric acid type A receptor inverse agonist L-655,708.

PubMed

Saab, Bechara J; Maclean, Ashley J B; Kanisek, Marijana; Zurek, Agnieszka A; Martin, Loren J; Roder, John C; Orser, Beverley A

2010-11-01

Memory blockade is an essential component of the anesthetic state. However, postanesthesia memory deficits represent an undesirable and poorly understood adverse effect. Inhibitory α5 subunit-containing γ-aminobutyric acid subtype A receptors (α5GABAA) are known to play a critical role in memory processes and are highly sensitive to positive modulation by anesthetics. We postulated that inhibiting the activity of α5GABAA receptors during isoflurane anesthesia would prevent memory deficits in the early postanesthesia period. Mice were pretreated with L-655,708, an α5GABAA receptor-selective inverse agonist, or vehicle. They were then exposed to isoflurane for 1 h (1.3%, or 1 minimum alveolar concentration, or air-oxygen control). Then, either 1 or 24 h later, mice were conditioned in fear-associated contextual and cued learning paradigms. In addition, the effect of L-655,708 on the immobilizing dose of isoflurane was studied. Motor coordination, sedation, anxiety, and the concentration of isoflurane in the brain at 5 min, 1 h, and 24 h after isoflurane were also examined. Motor and sensory function recovered within minutes after termination of isoflurane administration. In contrast, a robust deficit in contextual fear memory persisted for at least 24 h. The α5GABAA receptor inverse agonist, L-655,708, completely prevented memory deficits without changing the immobilizing dose of isoflurane. Trace concentrations of isoflurane were measured in the brain 24 h after treatment. Memory deficits occurred long after the sedative, analgesic, and anxiolytic effects of isoflurane subsided. L-655,708 prevented memory deficit, suggesting that an isoflurane interaction at α5GABAA receptors contributes to memory impairment during the early postanesthesia period.

Glutamate dehydrogenase (RocG) in Bacillus licheniformis WX-02: Enzymatic properties and specific functions in glutamic acid synthesis for poly-γ-glutamic acid production.

PubMed

Tian, Guangming; Wang, Qin; Wei, Xuetuan; Ma, Xin; Chen, Shouwen

2017-04-01

Poly-γ-glutamic acid (γ-PGA), a natural biopolymer, is widely used in cosmetics, medicine, food, water treatment, and agriculture owing to its features of moisture sequestration, cation chelation, non-toxicity and biodegradability. Intracellular glutamic acid, the substrate of γ-PGA, is a limiting factor for high yield in γ-PGA production. Bacillus subtilis and Bacillus licheniformis are both important γ-PGA producing strains, and B. subtilis synthesizes glutamic acid in vivo using the unique GOGAT/GS pathway. However, little is known about the glutamate synthesis pathway in B. licheniformis. The aim of this work was to characterize the glutamate dehydrogenase (RocG) in glutamic acid synthesis from B. licheniformis with both in vivo and in vitro experiments. By re-directing the carbon flux distribution, the rocG gene deletion mutant WX-02ΔrocG produced intracellular glutamic acid with a concentration of 90ng/log(CFU), which was only 23.7% that of the wild-type WX-02 (380ng/log(CFU)). Furthermore, the γ-PGA yield of mutant WX-02ΔrocG was 5.37g/L, a decrease of 45.3% compared to the wild type (9.82g/L). In vitro enzymatic assays of RocG showed that RocG has higher affinity for 2-oxoglutarate than glutamate, and the glutamate synthesis rate was far above degradation. This is probably the first study to reveal the glutamic acid synthesis pathway and the specific functions of RocG in B. licheniformis. The results indicate that γ-PGA production can be enhanced through improving intracellular glutamic acid synthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Optimization of γ-amino butyric acid production in a newly isolated Lactobacillus brevis.

PubMed

Binh, Tran Thi Thanh; Ju, Wan-Taek; Jung, Woo-Jin; Park, Ro-Dong

2014-01-01

An isolate from kimchi, identified as Lactobacillus brevis, accumulated γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter, in the culture medium. Optimal culture conditions for growth of L. brevis and production of GABA were 6 % (w/v) l-glutamic acid, 4 % (w/v) maltose, 2 % (w/v) yeast extract, 1 % (w/v) NaCl, 1 % (w/v) CaCl2, 2 g Tween 80/l, and 0.02 mM pyridoxal 5′-phosphate at initial pH 5.25 and 37 °C. GABA reached 44.4 g/l after 72 h cultivation with a conversion rate 99.7 %, based on the amount (6 %) of l-glutamic acid added. GABA was purified using ion exchange column chromatography with 70 % recovery and 97 % purity.

G Protein–Coupled Receptor-Type G Proteins Are Required for Light-Dependent Seedling Growth and Fertility in Arabidopsis[W

PubMed Central

Jaffé, Felix W.; Freschet, Gian-Enrico C.; Valdes, Billy M.; Runions, John; Terry, Matthew J.; Williams, Lorraine E.

2012-01-01

G protein–coupled receptor-type G proteins (GTGs) are highly conserved membrane proteins in plants, animals, and fungi that have eight to nine predicted transmembrane domains. They have been classified as G protein–coupled receptor-type G proteins that function as abscisic acid (ABA) receptors in Arabidopsis thaliana. We cloned Arabidopsis GTG1 and GTG2 and isolated new T-DNA insertion alleles of GTG1 and GTG2 in both Wassilewskija and Columbia backgrounds. These gtg1 gtg2 double mutants show defects in fertility, hypocotyl and root growth, and responses to light and sugars. Histological studies of shoot tissue reveal cellular distortions that are particularly evident in the epidermal layer. Stable expression of GTG1pro:GTG1-GFP (for green fluorescent protein) in Arabidopsis and transient expression in tobacco (Nicotiana tabacum) indicate that GTG1 is localized primarily to Golgi bodies and to the endoplasmic reticulum. Microarray analysis comparing gene expression profiles in the wild type and double mutant revealed differences in expression of genes important for cell wall function, hormone response, and amino acid metabolism. The double mutants isolated here respond normally to ABA in seed germination assays, root growth inhibition, and gene expression analysis. These results are inconsistent with their proposed role as ABA receptors but demonstrate that GTGs are fundamentally important for plant growth and development. PMID:23001037

Positive and Negative Allosteric Modulation of an α1β3γ2 γ-Aminobutyric Acid Type A (GABAA) Receptor by Binding to a Site in the Transmembrane Domain at the γ+-β− Interface*

PubMed Central

Jayakar, Selwyn S.; Zhou, Xiaojuan; Savechenkov, Pavel Y.; Chiara, David C.; Desai, Rooma; Bruzik, Karol S.; Miller, Keith W.; Cohen, Jonathan B.

2015-01-01

In the process of developing safer general anesthetics, isomers of anesthetic ethers and barbiturates have been discovered that act as convulsants and inhibitors of γ-aminobutyric acid type A receptors (GABAARs) rather than potentiators. It is unknown whether these convulsants act as negative allosteric modulators by binding to the intersubunit anesthetic-binding sites in the GABAAR transmembrane domain (Chiara, D. C., Jayakar, S. S., Zhou, X., Zhang, X., Savechenkov, P. Y., Bruzik, K. S., Miller, K. W., and Cohen, J. B. (2013) J. Biol. Chem. 288, 19343–19357) or to known convulsant sites in the ion channel or extracellular domains. Here, we show that S-1-methyl-5-propyl-5-(m-trifluoromethyl-diazirynylphenyl) barbituric acid (S-mTFD-MPPB), a photoreactive analog of the convulsant barbiturate S-MPPB, inhibits α1β3γ2 but potentiates α1β3 GABAAR responses. In the α1β3γ2 GABAAR, S-mTFD-MPPB binds in the transmembrane domain with high affinity to the γ+-β− subunit interface site with negative energetic coupling to GABA binding in the extracellular domain at the β+-α− subunit interfaces. GABA inhibits S-[3H]mTFD-MPPB photolabeling of γ2Ser-280 (γM2–15′) in this site. In contrast, within the same site GABA enhances photolabeling of β3Met-227 in βM1 by an anesthetic barbiturate, R-[3H]methyl-5-allyl-5-(m-trifluoromethyl-diazirynylphenyl)barbituric acid (mTFD-MPAB), which differs from S-mTFD-MPPB in structure only by chirality and two hydrogens (propyl versus allyl). S-mTFD-MPPB and R-mTFD-MPAB are predicted to bind in different orientations at the γ+-β− site, based upon the distance in GABAAR homology models between γ2Ser-280 and β3Met-227. These results provide an explanation for S-mTFD-MPPB inhibition of α1β3γ2 GABAAR function and provide a first demonstration that an intersubunit-binding site in the GABAAR transmembrane domain binds negative and positive allosteric modulators. PMID:26229099

Production of a new D-amino acid oxidase from the fungus Fusarium oxysporum.

PubMed

Gabler, M; Fischer, L

1999-08-01

The fungus Fusarium oxysporum produced a D-amino acid oxidase (EC 1. 4.3.3) in a medium containing glucose as the carbon and energy source and ammonium sulfate as the nitrogen source. The specific D-amino acid oxidase activity was increased up to 12.5-fold with various D-amino acids or their corresponding derivatives as inducers. The best inducers were D-alanine (2.7 microkat/g of dry biomass) and D-3-aminobutyric acid (2.6 microkat/g of dry biomass). The addition of zinc ions was necessary to permit the induction of peroxisomal D-amino acid oxidase. Bioreactor cultivations were performed on a 50-liter scale, yielding a volumetric D-amino acid oxidase activity of 17 microkat liter(-1) with D-alanine as an inducer. Under oxygen limitation, the volumetric activity was increased threefold to 54 microkat liter(-1) (3,240 U liter(-1)).

Medial Frontal Lobe Neurochemistry in Autism Spectrum Disorder is Marked by Reduced N-Acetylaspartate and Unchanged Gamma-Aminobutyric Acid and Glutamate + Glutamine Levels.

PubMed

Carvalho Pereira, Andreia; Violante, Inês R; Mouga, Susana; Oliveira, Guiomar; Castelo-Branco, Miguel

2018-05-01

The nature of neurochemical changes in autism spectrum disorder (ASD) remains controversial. We compared medial prefrontal cortex (mPFC) neurochemistry of twenty high-functioning children and adolescents with ASD without associated comorbidities and fourteen controls. We observed reduced total N-acetylaspartate (tNAA) and total creatine, increased Glx/tNAA but unchanged glutamate + glutamine (Glx) and unchanged absolute or relative gamma-aminobutyric acid (GABA+) in the ASD group. Importantly, both smaller absolute and relative GABA+ levels were associated with worse communication skills and developmental delay scores assessed by the autism diagnostic interview-revised (ADI-R). We conclude that tNAA is reduced in the mPFC in ASD and that glutamatergic metabolism may be altered due to unbalanced Glx/tNAA. Moreover, GABA+ is related to autistic symptoms assessed by the ADI-R.

Structure-activity relationships of seco-prezizaane terpenoids in gamma-aminobutyric acid receptors of houseflies and rats.

PubMed

Kuriyama, Tadahiko; Schmidt, Thomas J; Okuyama, Emi; Ozoe, Yoshihisa

2002-06-01

Thirteen seco-prezizaane terpenoids isolated from star anise species (Illcium floridanum, Illcium parviflorum, and Illcium verum) were investigated for their ability to inhibit the specific binding of [(3)H]4'-ethynyl-4-n-propylbicycloorthobenzoate (EBOB), a non-competitive antagonist of gamma-aminobutyric acid (GABA) receptors, to housefly-head and rat-brain membranes. Veranisatin A was found to be the most potent inhibitor in both membranes, with an IC(50)(fly) of 78.5 nM and an IC(50)(rat) of 271 nM, followed by anisatin (IC(50)(fly)=123 nM; IC(50)(rat)=282 nM). Six of the other 11 tested compounds were effective only in housefly-head membranes. Pseudoanisatin proved to display a high (>26-fold) selectivity for housefly versus rat GABA receptors (IC(50)(fly)=376 nM; IC(50)(rat) >10,000 nM). Although pseudoanisatin does not structurally resemble EBOB, Scatchard plots indicated that the two compounds bind to the same site in housefly receptors. Anisatin and pseudoanisatin exhibited moderate insecticidal activity against German cockroaches. Comparative molecular field analysis (CoMFA), a method of three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis, demonstrated that seco-prezizaane terpenoids can bind to the same site as do picrotoxane terpenoids such as picrotoxinin and picrodendrins, and the CoMFA maps allowed us to identify the parts of the molecules essential to high activity in housefly GABA receptors.

Prefrontal cortical gamma-aminobutyric acid transmission and cognitive function: drawing links to schizophrenia from preclinical research.

PubMed

Tse, Maric T; Piantadosi, Patrick T; Floresco, Stan B

2015-06-01

Cognitive dysfunction in schizophrenia is one of the most pervasive and debilitating aspects of the disorder. Among the numerous neural abnormalities that may contribute to schizophrenia symptoms, perturbations in markers for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), particularly within the frontal lobes, are some of the most reliable alterations observed at postmortem examination. However, how prefrontal GABA dysfunction contributes to cognitive impairment in schizophrenia remains unclear. We provide an overview of postmortem GABAergic perturbations in the brain affected by schizophrenia and describe circumstantial evidence linking these alterations to cognitive dysfunction. In addition, we conduct a survey of studies using neurodevelopmental, genetic, and pharmacologic rodent models that induce schizophrenia-like cognitive impairments, highlighting the convergence of these mechanistically distinct approaches to prefrontal GABAergic disruption. We review preclinical studies that have directly targeted prefrontal cortical GABAergic transmission using local application of GABAA receptor antagonists. These studies have provided an important link between GABA transmission and cognitive dysfunction in schizophrenia because they show that reducing prefrontal inhibitory transmission induces various cognitive, emotional, and dopaminergic abnormalities that resemble aspects of the disorder. These converging clinical and preclinical findings provide strong support for the idea that perturbations in GABA signaling drive certain forms of cognitive dysfunction in schizophrenia. Future studies using this approach will yield information to refine further a putative "GABA hypothesis" of schizophrenia. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Gamma-Aminobutyric Acid Concentration is Reduced in Visual Cortex in Schizophrenia and Correlates with Orientation-Specific Surround Suppression

PubMed Central

Yoon, Jong H.; Maddock, Richard J.; Rokem, Ariel; Silver, Michael A.; Minzenberg, Michael J.; Ragland, J. Daniel; Carter, Cameron S.

2010-01-01

The neural mechanisms underlying cognitive deficits in schizophrenia remain largely unknown. The gamma-aminobutyric acid (GABA) hypothesis proposes that reduced neuronal GABA concentration and neurotransmission results in cognitive impairments in schizophrenia. However, few in vivo studies have directly examined this hypothesis. We employed magnetic resonance spectroscopy (MRS) at high field to measure visual cortical GABA levels in 13 subjects with schizophrenia and 13 demographically matched healthy control subjects. We found that the schizophrenia group had an approximately 10% reduction in GABA concentration. We further tested the GABA hypothesis by examining the relationship between visual cortical GABA levels and orientation-specific surround suppression (OSSS), a behavioral measure of visual inhibition thought to be dependent on GABAergic synaptic transmission. Previous work has shown that subjects with schizophrenia exhibit reduced OSSS of contrast discrimination (Yoon et al., 2009). For subjects with both MRS and OSSS data (n=16), we found a highly significant positive correlation (r=0.76) between these variables. GABA concentration was not correlated with overall contrast discrimination performance for stimuli without a surround (r=-0.10). These results suggest that a neocortical GABA deficit in subjects with schizophrenia leads to impaired cortical inhibition and that GABAergic synaptic transmission in visual cortex plays a critical role in OSSS. PMID:20220012

Analysis of persistent changes to γ-aminobutyric acid receptor gene expression in Plutella xylostella subjected to sublethal amounts of spinosad.

PubMed

Yin, X-H; Wu, Q-J; Zhang, Y-J; Long, Y-H; Wu, X-M; Li, R-Y; Wang, M; Tian, X-L; Jiao, X-G

2016-07-25

A multi-generational approach was used to investigate the persistent effects of a sub-lethal dose of spinosad in Plutella xylostella. The susceptibility of various sub-populations of P. xylostella to spinosad and the effects of the insecticide on the gene expression of γ-aminobutyric acid receptor (GABAR) were determined. The results of a leaf dip bioassay showed that the sensitivity of P. xylostella to spinosad decreased across generations. The sub-strains had been previously selected based on a determined LC25 of spinosad. Considering that GABA-gated chloride channels are the primary targets of spinosad, the cDNA of P. xylostella was used to clone GABARα by using reverse transcription-polymerase chain reaction (RT-PCR). The mature peptide cDNA was 1477-bp long and contained a 1449-bp open reading frame encoding a protein of 483 amino acids. The resulting amino acid sequence was used to generate a neighbor-joining dendrogram, and homology search was conducted using NCBI BLAST. The protein had high similarity with the known GABAR sequence from P. xylostella. Subsequent semi-quantitative RT-PCR and real-time PCR analyses indicated that the GABAR transcript levels in the spinosad-resistant strain (RR, 145.82-fold) and in Sub1 strain (selected with LC25 spinosad for one generation) were the highest, followed by those in the spinosad-susceptible strain, the Sub10 strain (selected for ten generations), and the Sub5 strain (selected for five generations). This multi-generational study found significant correlations between spinosad susceptibility and GABAR gene expression, providing insights into the long-term effects of sub-lethal insecticide exposure and its potential to lead to the development of insecticide-resistant insect populations.

Analysis of the effects on body temperature of intracerebroventricular injection in anaesthetized dogs of gamma-aminobutyric acid

PubMed Central

Dhumal, V.R.; Gulati, O.D.; Raghunath, P.R.; Sivaramakrishna, N.

1974-01-01

1 The cerebral ventricles of dogs under intravenous pentobarbitone sodium anaesthesia, were perfused with artificial cerebro-spinal fluid (CSF) at a rate of 0.4-0.5 ml/min from the ventricular to the aqueductal cannulae. The effluent was collected from the aqueductal cannula in 20 min samples. The animals' temperatures were recorded from the rectum. 2 γ-Aminobutyric acid (GABA) 0.1-5 mg when injected into the ventricles produced variable temperature effects. Doses of 0.1 and 0.5 mg always produced hyperthermia and 1 and 5 mg doses sometimes produced hyperthermia and sometimes hypothermia. 3 Intraventricular perfusion with 2-bromolysergic acid diethylamide (BOL) and hyoscine did not block hyperthermia. Tests on the rat isolated stomach strip or the guinea-pig isolated superfused ileum for the possible release, respectively, of 5-hydroxytryptamine or acetylcholine by GABA were negative. 4 When tested for the presence of prostaglandin E(PGE)-like substances on the isolated rat stomach strip, both the control effluent and the GABA effluent showed activity, the latter being much more potent. There was a temporal correlation between this effect and hyperthermia. Intraventricularly administered sodium salicylate converted the GABA-induced hyperthermia to hypothermia and blocked the release of PGE-like substances. 5 Hypothermia induced by GABA alone or in the presence of sodium salicylate was associated with the release of noradrenaline into the effluent. 6 Intraventricular administration of GABA in reserpinized dogs produced hyperthermia and not hypothermia. Similar results were obtained with phentolamine perfusion in normal dogs. 7 Perfusion with calcium-free solution blocked both the noradrenaline-releasing and hypothermic actions of GABA. 8 It is concluded that hyperthermia associated with intraventricular injections of GABA is due to the release of PGE-like substance and hypothermia is due to the release of noradrenaline. PMID:4155652

Effects of rumen-protected γ-aminobutyric acid on performance and nutrient digestibility in heat-stressed dairy cows.

PubMed

Cheng, J B; Bu, D P; Wang, J Q; Sun, X Z; Pan, L; Zhou, L Y; Liu, W

2014-09-01

This experiment was conducted to investigate the effects of rumen-protected γ-aminobutyric acid (GABA) on performance and nutrient digestibility in heat-stressed dairy cows. Sixty Holstein dairy cows (141±15 d in milk, 35.9±4.3kg of milk/d, and parity 2.0±1.1) were randomly assigned to 1 of 4 treatments according to a completely randomized block design. Treatments consisted of 0 (control), 40, 80, or 120mg of true GABA/kg of dry matter (DM). The trial lasted 10wk. The average temperature-humidity indices at 0700, 1400, and 2200h were 78.4, 80.2, and 78.7, respectively. Rectal temperatures decreased linearly at 0700, 1400, and 2200h with increasing GABA concentration. Supplementation of GABA had no effect on respiration rates at any time point. Dry matter intake, energy-corrected milk, 4% fat-corrected milk, and milk fat yield tended to increase linearly with increasing GABA concentration. Supplementation of GABA affected, in a quadratic manner, milk protein and lactose concentrations, and milk protein yield, and the peak values were reached at a dose of 40mg of GABA/kg. Milk urea nitrogen concentration responded quadratically. Total solids content increased linearly with increasing GABA concentration. Supplementation of GABA had no effect on milk yield, lactose production, total solids, milk fat concentration, somatic cell score, or feed efficiency. Apparent total-tract digestibilities of DM, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber were similar among treatments. These results indicate that rumen-protected GABA supplementation to dairy cows can alleviate heat stress by reducing rectal temperature, increase DM intake and milk production, and improve milk composition. The appropriate supplemental GABA level for heat-stressed dairy cows is 40mg/kg of DM. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

METABOLISM OF ω-AMINO ACIDS V.

PubMed Central

Hardman, John K.; Stadtman, Thressa C.

1963-01-01

Hardman, John K. (National Heart Institute, National Institutes of Health, Bethesda, Md.) and Thressa C. Stadtman. Metabolism of ω-amino acids. V. Energetics of the γ-aminobutyrate fermentation by Clostridium aminobutyricum. J. Bacteriol. 85:1326–1333. 1963.—Clostridium aminobutyricum utilizes γ-aminobutyrate as its sole carbon, nitrogen, and energy source, producing ammonia, acetate, and butyrate as a result of this fermentation. Coenzyme A (CoA)-transferase, phosphotransacetylase, and acetokinase activities have been demonstrated in crude extracts of the organism; the coupling of the reactions catalyzed by these enzymes to the fermentation reactions provides a mechanism whereby C. aminobutyricum can obtain energy, in the form of adenosine triphosphate, from the decomposition of γ-aminobutyrate. Indirect evidence of additional phosphorylation, at the electron-transport level, has been obtained from molar growth yield studies and from the inhibition by 2,4-dinitrophenol of butyrate synthesis from γ-aminobutyrate and from crotonyl-CoA. PMID:14047225

Neurons and terminals in the retrohippocampal region in the rat's brain identified by anti-gamma-aminobutyric acid and anti-glutamic acid decarboxylase immunocytochemistry.

PubMed

Köhler, C; Wu, J Y; Chan-Palay, V

1985-01-01

The distribution of gamma-aminobutyric acid (GABA) containing nerve cells and terminals was studied at the light and electron microscopic levels in the retrohippocampal region of the rat by using anti-glutamic acid decarboxylase (GAD) and anti-GABA antibodies in immunocytochemistry. Large numbers of GAD and GABA stained cells were found in all retrohippocampal structures. At the ultrastructural level, the immunoreactivity against GABA and against the synthesizing enzyme GAD was localized to cytoplasmic structures, including loose clumps of rough endoplasmic reticulum, ribosomal arrays, outer mitochondrial surfaces and in axonal boutons. The GAD- and GABA-immunoreactive(-i) cells were found in all subfields of the retrohippocampal region (e.g., the subicular complex, the entorhinal area). Within the entorhinal area a slightly larger number of immunoreactive cells could be detected in layers II and III than in the other layers. In the subiculum, pre- and parasubiculum the GAD and GABA-i cells were present in relatively large numbers in all layers, except the molecular layer, which contained only a small number of GABA cells. Within the entorhinal area, GAD and GABA stained cells ranged in size from small (13 micron in diameter) to large (22 micron in diameter). A large number of different morphological classes of cells were found, except pyramidal and stellate cells. In the pre- and parasubiculum, on the other hand, the GABA cells were generally small to medium in size and morphologically more homogeneous than in the subiculum and entorhinal area. The entire retrohippocampal region was densely innervated by GABA preterminal processes, with little variation in the regional density of innervation. Within the entorhinal area, presubiculum and subiculum, a clear difference was found in the laminar pattern of innervation. In all three subfields the densest innervation was in layer II. In the entorhinal area both GAD- and GABA-i axons form palisades of fibers around the

Abscisic Acid Acts as a Blocker of the Bitter Taste G Protein-Coupled Receptor T2R4.

PubMed

Pydi, Sai P; Jaggupilli, Appalaraju; Nelson, Ken M; Abrams, Suzanne R; Bhullar, Rajinder P; Loewen, Michele C; Chelikani, Prashen

2015-04-28

Bitter taste receptors (T2Rs) belong to the G protein-coupled receptor superfamily. In humans, 25 T2Rs mediate bitter taste sensation. In addition to the oral cavity, T2Rs are expressed in many extraoral tissues, including the central nervous system, respiratory system, and reproductive system. To understand the mechanistic roles of the T2Rs in oral and extraoral tissues, novel blockers or antagonists are urgently needed. Recently, we elucidated the binding pocket of T2R4 for its agonist quinine, and an antagonist and inhibitory neurotransmitter, γ-aminobutyric acid. This structure-function information about T2R4 led us to screen the plant hormone abscisic acid (ABA), its precursor (xanthoxin), and catabolite phaseic acid for their ability to bind and activate or inhibit T2R4. Molecular docking studies followed by functional assays involving calcium imaging confirmed that ABA is an antagonist with an IC50 value of 34.4 ± 1.1 μM. However, ABA precursor xanthoxin acts as an agonist on T2R4. Interestingly, molecular model-guided site-directed mutagenesis suggests that the T2R4 residues involved in quinine binding are also predominantly involved in binding to the novel antagonist, ABA. The antagonist ability of ABA was tested using another T2R4 agonist, yohimbine. Our results suggest that ABA does not inhibit yohimbine-induced T2R4 activity. The discovery of natural bitter blockers has immense nutraceutical and physiological significance and will help in dissecting the T2R molecular pathways in various tissues.

Bidirectional Homeostatic Regulation of a Depression-Related Brain State by Gamma-Aminobutyric Acidergic Deficits and Ketamine Treatment.

PubMed

Ren, Zhen; Pribiag, Horia; Jefferson, Sarah J; Shorey, Matthew; Fuchs, Thomas; Stellwagen, David; Luscher, Bernhard

2016-09-15

Major depressive disorder is increasingly recognized to involve functional deficits in both gamma-aminobutyric acid (GABA)ergic and glutamatergic synaptic transmission. To elucidate the relationship between these phenotypes, we used GABAA receptor γ2 subunit heterozygous (γ2(+/-)) mice, which we previously characterized as a model animal with construct, face, and predictive validity for major depressive disorder. To assess possible consequences of GABAergic deficits on glutamatergic transmission, we quantitated the cell surface expression of N-methyl-D-aspartate (NMDA)-type and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptors and the function of synapses in the hippocampus and medial prefrontal cortex of γ2(+/-) mice. We also analyzed the effects of an acute dose of the experimental antidepressant ketamine on all these parameters in γ2(+/-) versus wild-type mice. Modest defects in GABAergic synaptic transmission of γ2(+/-) mice resulted in a strikingly prominent homeostatic-like reduction in the cell surface expression of NMDA-type and AMPA-type glutamate receptors, along with prominent functional impairment of glutamatergic synapses in the hippocampus and medial prefrontal cortex. A single subanesthetic dose of ketamine normalized glutamate receptor expression and synaptic function of γ2(+/-) mice to wild-type levels for a prolonged period, along with antidepressant-like behavioral consequences selectively in γ2(+/-) mice. The GABAergic synapses of γ2(+/-) mice were potentiated by ketamine in parallel but only in the medial prefrontal cortex. Depressive-like brain states that are caused by GABAergic deficits involve a homeostatic-like reduction of glutamatergic transmission that is reversible by an acute, subanesthetic dose of ketamine, along with regionally selective potentiation of GABAergic synapses. The data merge the GABAergic and glutamatergic deficit hypotheses of major depressive disorder. Copyright © 2016

Assessment of Homology Templates and an Anesthetic Binding Site within the γ-Aminobutyric Acid Receptor

PubMed Central

Bertaccini, Edward J.; Yoluk, Ozge; Lindahl, Erik R.; Trudell, James R.

2013-01-01

Background Anesthetics mediate portions of their activity via modulation of the γ-aminobutyric acid receptor (GABAaR). While its molecular structure remains unknown, significant progress has been made towards understanding its interactions with anesthetics via molecular modeling. Methods The structure of the torpedo acetylcholine receptor (nAChRα), the structures of the α4 and β2 subunits of the human nAChR, the structures of the eukaryotic glutamate-gated chloride channel (GluCl), and the prokaryotic pH sensing channels, from Gloeobacter violaceus and Erwinia chrysanthemi, were aligned with the SAlign and 3DMA algorithms. A multiple sequence alignment from these structures and those of the GABAaR was performed with ClustalW. The Modeler and Rosetta algorithms independently created three-dimensional constructs of the GABAaR from the GluCl template. The CDocker algorithm docked a congeneric series of propofol derivatives into the binding pocket and scored calculated binding affinities for correlation with known GABAaR potentiation EC50’s. Results Multiple structure alignments of templates revealed a clear consensus of residue locations relevant to anesthetic effects except for torpedo nAChR. Within the GABAaR models generated from GluCl, the residues notable for modulating anesthetic action within transmembrane segments 1, 2, and 3 converged on the intersubunit interface between alpha and beta subunits. Docking scores of a propofol derivative series into this binding site showed strong linear correlation with GABAaR potentiation EC50. Conclusion Consensus structural alignment based on homologous templates revealed an intersubunit anesthetic binding cavity within the transmembrane domain of the GABAaR, which showed correlation of ligand docking scores with experimentally measured GABAaR potentiation. PMID:23770602

Assessment of homology templates and an anesthetic binding site within the γ-aminobutyric acid receptor.

PubMed

Bertaccini, Edward J; Yoluk, Ozge; Lindahl, Erik R; Trudell, James R

2013-11-01

Anesthetics mediate portions of their activity via modulation of the γ-aminobutyric acid receptor (GABAaR). Although its molecular structure remains unknown, significant progress has been made toward understanding its interactions with anesthetics via molecular modeling. The structure of the torpedo acetylcholine receptor (nAChRα), the structures of the α4 and β2 subunits of the human nAChR, the structures of the eukaryotic glutamate-gated chloride channel (GluCl), and the prokaryotic pH-sensing channels, from Gloeobacter violaceus and Erwinia chrysanthemi, were aligned with the SAlign and 3DMA algorithms. A multiple sequence alignment from these structures and those of the GABAaR was performed with ClustalW. The Modeler and Rosetta algorithms independently created three-dimensional constructs of the GABAaR from the GluCl template. The CDocker algorithm docked a congeneric series of propofol derivatives into the binding pocket and scored calculated binding affinities for correlation with known GABAaR potentiation EC50s. Multiple structure alignments of templates revealed a clear consensus of residue locations relevant to anesthetic effects except for torpedo nAChR. Within the GABAaR models generated from GluCl, the residues notable for modulating anesthetic action within transmembrane segments 1, 2, and 3 converged on the intersubunit interface between α and β subunits. Docking scores of a propofol derivative series into this binding site showed strong linear correlation with GABAaR potentiation EC50. Consensus structural alignment based on homologous templates revealed an intersubunit anesthetic binding cavity within the transmembrane domain of the GABAaR, which showed a correlation of ligand docking scores with experimentally measured GABAaR potentiation.

Reducing prefrontal gamma-aminobutyric acid activity induces cognitive, behavioral, and dopaminergic abnormalities that resemble schizophrenia.

PubMed

Enomoto, Takeshi; Tse, Maric T; Floresco, Stan B

2011-03-01

Perturbations in gamma-aminobutyric acid (GABA)-related markers have been reported in the prefrontal cortex of schizophrenic patients. However, a preclinical assessment of how suppression of prefrontal cortex GABA activity may reflect behavioral and cognitive pathologies observed in schizophrenia is forthcoming. We assessed the effects of pharmacologic blockade of prefrontal cortex GABA(A) receptors in rats on executive functions and other behaviors related to schizophrenia, as well as neural activity of midbrain dopamine neurons. Blockade of prefrontal cortex GABA(A) receptors with bicuculline (12.5-50 ng) did not affect working memory accuracy but did increase response latencies, resembling speed of processing deficits observed in schizophrenia. Prefrontal cortex GABA(A) blockade did not impede simple discrimination or reversal learning but did impair set-shifting in a manner dependent on when these treatments were given. Reducing GABA activity before the set-shift impaired the ability to acquire a novel strategy, whereas treatment before the initial discrimination increased perseveration during the shift. Latent inhibition was unaffected by bicuculline infusions before the preexposure/conditioning phases, suggesting that reduced prefrontal cortex GABA activity does not impair "learned irrelevance." GABA(A) blockade increased locomotor activity and showed synergic effects with a subthreshold dose of amphetamine. Furthermore, reducing medial prefrontal cortex GABA activity selectively increased phasic burst firing of ventral tegmental area dopamine neurons, without altering the their overall population activity. These results suggest that prefrontal cortex GABA hypofunction may be a key contributing factor to deficits in speed of processing, cognitive flexibility, and enhanced phasic dopamine activity observed in schizophrenia. Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Reduced gamma-aminobutyric acid is associated with emotional and behavioral problems in Prader-Willi syndrome.

PubMed

Rice, Lauren J; Lagopoulos, Jim; Brammer, Michael; Einfeld, Stewart L

2016-12-01

Prader-Willi syndrome (PWS) is characterized by infantile hypotonia, hypogonadism, small hands and feet, distinct facial features and usually intellectual impairment. The disorder is associated with severe behavioral disturbances which include hyperphagia leading to morbid obesity, temper outbursts, skin-picking, and compulsive behaviors. While the brain mechanisms that underpin these disturbances are unknown these behaviors suggest a lack of inhibition and thus gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter may be implicated. In the present study, we investigated in vivo brain GABA and its relationship with emotion and behavior in individuals with PWS. Single voxel proton magnetic resonance spectroscopy (1H-MRS) was performed on 15 individuals with PWS and 15 age- and gender-matched typically developing controls. GABA levels were measured in the parieto-occipital lobe. All other metabolite levels (N-acetyl aspartate, myo-Inositol, glutathione, glutamate, and glutamine + glutamate) were measured in the anterior cingulate cortex (ACC). GABA levels were significantly lower in the participants with PWS who had clinically significant emotional and behavioral problems relative to typically developing control participants and participants with PWS who did not have emotional and behavioral problems within the clinically significant range. GABA levels were negatively correlated with total behavioral problem scores as well as temper outbursts, skin-picking, depression, social relating difficulties, and a tendency to be self-absorbed. Our data suggests that alterations of the GABAergic system may play an important role in aspects of the pathophysiology of PWS. Pathological mechanism found in PWS may be relevant to understanding the control of similar behaviors in the general population. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Somatostatin-Positive Gamma-Aminobutyric Acid Interneuron Deficits in Depression: Cortical Microcircuit and Therapeutic Perspectives.

PubMed

Fee, Corey; Banasr, Mounira; Sibille, Etienne

2017-10-15

The functional integration of external and internal signals forms the basis of information processing and is essential for higher cognitive functions. This occurs in finely tuned cortical microcircuits whose functions are balanced at the cellular level by excitatory glutamatergic pyramidal neurons and inhibitory gamma-aminobutyric acidergic (GABAergic) interneurons. The balance of excitation and inhibition, from cellular processes to neural network activity, is characteristically disrupted in multiple neuropsychiatric disorders, including major depressive disorder (MDD), bipolar disorder, anxiety disorders, and schizophrenia. Specifically, nearly 3 decades of research demonstrate a role for reduced inhibitory GABA level and function across disorders. In MDD, recent evidence from human postmortem and animal studies suggests a selective vulnerability of GABAergic interneurons that coexpress the neuropeptide somatostatin (SST). Advances in cell type-specific molecular genetics have now helped to elucidate several important roles for SST interneurons in cortical processing (regulation of pyramidal cell excitatory input) and behavioral control (mood and cognition). Here, we review evidence for altered inhibitory function arising from GABAergic deficits across disorders and specifically in MDD. We then focus on properties of the cortical microcircuit, where SST-positive GABAergic interneuron deficits may disrupt functioning in several ways. Finally, we discuss the putative origins of SST cell deficits, as informed by recent research, and implications for therapeutic approaches. We conclude that deficits in SST interneurons represent a contributing cellular pathology and therefore a promising target for normalizing altered inhibitory function in MDD and other disorders with reduced SST cell and GABA functions. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Enhancing Contents of γ-Aminobutyric Acid (GABA) and Other Micronutrients in Dehulled Rice during Germination under Normoxic and Hypoxic Conditions.

PubMed

Ding, Junzhou; Yang, Tewu; Feng, Hao; Dong, Mengyi; Slavin, Margaret; Xiong, Shanbai; Zhao, Siming

2016-02-10

Biofortification of staple grains with high contents of essential micronutrients is an important strategy to overcome micronutrient malnutrition. However, few attempts have targeted at γ-aminobutyric acid (GABA), a functional nutrient for aging populations. In this study, two rice cultivars, Heinuo and Xianhui 207, were used to investigate changes in GABA and other nutritional compounds of dehulled rice after germination under normoxic and hypoxic conditions. Forty-one metabolites were identified in both cultivars treated by normoxic germination, whereas the germinated dehulled rice of Heinuo and Xianhui 207 under hypoxic treatment had 43 and 41 metabolites identified, respectively. GABA increased in dehulled rice after germination, especially under hypoxia. Meanwhile, a number of other health-beneficial and/or flavor-related compounds such as lysine and d-mannose increased after the hypoxic treatment. The accumulation of GABA exhibited genotype-specific modes in both normoxic and hypoxic treatments. With regard to GABA production, Xianhui 207 was more responsive to the germination process than Heinuo, whereas Heinuo was more responsive to hypoxia than Xianhui 207. This study provides a promising approach to biofortify dehulled rice with increased GABA and other nutrients through metabolomic-based regulation.

Dual mechanisms regulating glutamate decarboxylases and accumulation of gamma-aminobutyric acid in tea (Camellia sinensis) leaves exposed to multiple stresses

PubMed Central

Mei, Xin; Chen, Yiyong; Zhang, Lingyun; Fu, Xiumin; Wei, Qing; Grierson, Don; Zhou, Ying; Huang, Yahui; Dong, Fang; Yang, Ziyin

2016-01-01

γ-Aminobutyric acid (GABA) is one of the major inhibitory neurotransmitters in the central nervous system. It has multiple positive effects on mammalian physiology and is an important bioactive component of tea (Camellia sinensis). GABA generally occurs at a very low level in plants but GABA content increases substantially after exposure to a range of stresses, especially oxygen-deficiency. During processing of tea leaves, a combination of anoxic stress and mechanical damage are essential for the high accumulation of GABA. This is believed to be initiated by a change in glutamate decarboxylase activity, but the underlying mechanisms are unclear. In the present study we characterized factors regulating the expression and activity of three tea glutamate decarboxylase genes (CsGAD1, 2, and 3), and their encoded enzymes. The results suggests that, unlike the model plant Arabidopsis thaliana, there are dual mechanisms regulating the accumulation of GABA in tea leaves exposed to multiple stresses, including activation of CsGAD1 enzymatic activity by calmodulin upon the onset of the stress and accumulation of high levels of CsGAD2 mRNA induced by a combination of anoxic stress and mechanical damage. PMID:27021285

Dual mechanisms regulating glutamate decarboxylases and accumulation of gamma-aminobutyric acid in tea (Camellia sinensis) leaves exposed to multiple stresses.

PubMed

Mei, Xin; Chen, Yiyong; Zhang, Lingyun; Fu, Xiumin; Wei, Qing; Grierson, Don; Zhou, Ying; Huang, Yahui; Dong, Fang; Yang, Ziyin

2016-03-29

γ-Aminobutyric acid (GABA) is one of the major inhibitory neurotransmitters in the central nervous system. It has multiple positive effects on mammalian physiology and is an important bioactive component of tea (Camellia sinensis). GABA generally occurs at a very low level in plants but GABA content increases substantially after exposure to a range of stresses, especially oxygen-deficiency. During processing of tea leaves, a combination of anoxic stress and mechanical damage are essential for the high accumulation of GABA. This is believed to be initiated by a change in glutamate decarboxylase activity, but the underlying mechanisms are unclear. In the present study we characterized factors regulating the expression and activity of three tea glutamate decarboxylase genes (CsGAD1, 2, and 3), and their encoded enzymes. The results suggests that, unlike the model plant Arabidopsis thaliana, there are dual mechanisms regulating the accumulation of GABA in tea leaves exposed to multiple stresses, including activation of CsGAD1 enzymatic activity by calmodulin upon the onset of the stress and accumulation of high levels of CsGAD2 mRNA induced by a combination of anoxic stress and mechanical damage.

Exogenous γ-Aminobutyric Acid Improves the Structure and Function of Photosystem II in Muskmelon Seedlings Exposed to Salinity-Alkalinity Stress

PubMed Central

Xu, Weinan; Zhen, Ai; Zhang, Liang; Hu, Xiaohui

2016-01-01

Gamma-aminobutyric acid (GABA) is important in plant responses to environmental stresses. We wished to clarify the role of GABA in maintenance of photosynthesis in muskmelon seedlings (Cucumis melo L., cv. Yipintianxia) during saline-alkaline stress. To this end, we assessed the effect of GABA on the structure and function of the photosynthetic apparatus in muskmelon seedlings grown under saline-alkaline stress. These stresses in combination reduced net photosynthetic rate, gas-exchange, and inhibited photosystem II (PSII) electron transport as measured by the JIP-test. They also reduced the activity of chloroplast ATPases and disrupted the internal lamellar system of the thylakoids. Exogenous GABA alleviated the stress-induced reduction of net photosynthesis, the activity of chloroplast ATPases, and overcame some of the damaging effects of stress on the chloroplast structure. Based on interpretation of the JIP-test, we conclude that exogenous GABA alleviated stress-related damage on the acceptor side of PSII. It also restored energy distribution, the reaction center status, and enhanced the ability of PSII to repair reaction centers in stressed seedlings. GABA may play a crucial role in protecting the chloroplast structure and function of PSII against the deleterious effects of salinity-alkalinity stress. PMID:27764179

Improved fermentative production of gamma-aminobutyric acid via the putrescine route: Systems metabolic engineering for production from glucose, amino sugars, and xylose.

PubMed

Jorge, João M P; Nguyen, Anh Q D; Pérez-García, Fernando; Kind, Stefanie; Wendisch, Volker F

2017-04-01

Gamma-aminobutyric acid (GABA) is a non-protein amino acid widespread in Nature. Among the various uses of GABA, its lactam form 2-pyrrolidone can be chemically converted to the biodegradable plastic polyamide-4. In metabolism, GABA can be synthesized either by decarboxylation of l-glutamate or by a pathway that starts with the transamination of putrescine. Fermentative production of GABA from glucose by recombinant Corynebacterium glutamicum has been described via both routes. Putrescine-based GABA production was characterized by accumulation of by-products such as N-acetyl-putrescine. Their formation was abolished by deletion of the spermi(di)ne N-acetyl-transferase gene snaA. To improve provision of l-glutamate as precursor 2-oxoglutarate dehydrogenase activity was reduced by changing the translational start codon of the chromosomal gene for 2-oxoglutarate dehydrogenase subunit E1o to the less preferred TTG and by maintaining the inhibitory protein OdhI in its inhibitory form by changing amino acid residue 15 from threonine to alanine. Putrescine-based GABA production by the strains described here led to GABA titers up to 63.2 g L -1 in fed-batch cultivation at maximum volumetric productivities up to 1.34 g L -1  h -1 , the highest volumetric productivity for fermentative GABA production reported to date. Moreover, GABA production from the carbon sources xylose, glucosamine, and N-acetyl-glucosamine that do not have competing uses in the food or feed industries was established. Biotechnol. Bioeng. 2017;114: 862-873. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

γ-Aminobutyric acid addition alleviates ammonium toxicity by limiting ammonium accumulation in rice (Oryza sativa) seedlings.

PubMed

Ma, Xiaoling; Zhu, Changhua; Yang, Na; Gan, Lijun; Xia, Kai

2016-12-01

Excessive use of nitrogen (N) fertilizer has increased ammonium (NH 4 + ) accumulation in many paddy soils to levels that reduce rice vegetative biomass and yield. Based on studies of NH 4 + toxicity in rice (Oryza sativa, Nanjing 44) seedlings cultured in agar medium, we found that NH 4 + concentrations above 0.75 mM inhibited the growth of rice and caused NH 4 + accumulation in both shoots and roots. Use of excessive NH 4 + also induced rhizosphere acidification and inhibited the absorption of K, Ca, Mg, Fe and Zn in rice seedlings. Under excessive NH 4 + conditions, exogenous γ-aminobutyric acid (GABA) treatment limited NH 4 + accumulation in rice seedlings, reduced NH 4 + toxicity symptoms and promoted plant growth. GABA addition also reduced rhizosphere acidification and alleviated the inhibition of Ca, Mg, Fe and Zn absorption caused by excessive NH 4 + . Furthermore, we found that the activity of glutamine synthetase/NADH-glutamate synthase (GS; EC 6.3.1.2/NADH-GOGAT; EC1.4.1.14) in root increased gradually as the NH 4 + concentration increased. However, when the concentration of NH 4 + is more than 3 mM, GABA treatment inhibited NH 4 + -induced increases in GS/NADH-GOGAT activity. The inhibition of ammonium assimilation may restore the elongation of seminal rice roots repressed by high NH 4 + . These results suggest that mitigation of ammonium accumulation and assimilation is essential for GABA-dependent alleviation of ammonium toxicity in rice seedlings. © 2016 Scandinavian Plant Physiology Society.

Reduced γ-Aminobutyric Acid in Occipital and Anterior Cingulate Cortices in Primary Insomnia: a Link to Major Depressive Disorder?

PubMed Central

Plante, David T; Jensen, J Eric; Schoerning, Laura; Winkelman, John W

2012-01-01

Insomnia is closely related to major depressive disorder (MDD) both cross-sectionally and longitudinally, and as such, offers potential opportunities to refine our understanding of the neurobiology of both sleep and mood disorders. Clinical and basic science data suggest a role for reduced γ-aminobutyric acid (GABA) in both MDD and primary insomnia (PI). Here, we have utilized single-voxel proton magnetic spectroscopy (1H-MRS) at 4 Tesla to examine GABA relative to total creatine (GABA/Cr) in the occipital cortex (OC), anterior cingulate cortex (ACC), and thalamus in 20 non-medicated adults with PI (12 women) and 20 age- and sex-matched healthy sleeper comparison subjects. PI subjects had significantly lower GABA/Cr in the OC (p=0.0005) and ACC (p=0.03) compared with healthy sleepers. There was no significant difference in thalamic GABA/Cr between groups. After correction for multiple comparisons, GABA/Cr did not correlate significantly with insomnia severity measures among PI subjects. This study is the first to demonstrate regional reductions of GABA in PI in the OC and ACC. Reductions in GABA in similar brain regions in MDD using 1H-MRS suggest a common reduction in cortical GABA among PI and mood disorders. PMID:22318195

High Gama-Aminobutyric Acid Contents Involved in Abamectin Resistance and Predation, an Interesting Phenomenon in Spider Mites

PubMed Central

Xu, Zhifeng; Liu, Yanchao; Wei, Peng; Feng, Kaiyang; Niu, Jinzhi; Shen, Guangmao; Lu, Wencai; Xiao, Wei; Wang, Jinjun; Smagghe, Guy J.; Xu, Qiang; He, Lin

2017-01-01

Abamectin has been widely used as an insecticide/acaricide for more than 30 years because of its superior bioactivity. Recently, an interesting phenomenon was identified in the carmine spider mite, Tetranychus cinnabarinus, an important pest in agriculture. The gamma aminobutyric acid (GABA) contents in a laboratory abamectin resistant strain of T. cinnabarinus (AbR) were significantly increased. Decreases in activity and mRNA expression of GABA transaminase (GABA-T) were responsible for GABA accumulation in AbR mites. To clarify the mechanism of GABA accumulation mediated abamectin resistance, three artificial approaches were conducted to increase GABA contents in susceptible mites, including feeding of vigabatrin (a specific inhibitor of GABA-T), feeding of exogenous GABA, and inhibition of GABA-T gene expression. The results showed that susceptible mites developed resistance to abamectin when the GABA contents were artificially increased. We also observed that the mites with higher GABA contents moved more slowly, which is consistent with the fact that GABA is an inhibitory neurotransmitter in arthropods. Subsequently, functional response assays revealed that predation rates of predatory mites on GABA accumulated abamectin-resistant mites were much higher than control groups. The tolerance to abamectin, slow crawling speed, and vulnerability to predators were all resulted from GABA accumulation. This relationship between GABA and predation was also confirmed in a field-collected population. Our finding indicates that predatory mites might be used as a tool for biological control to circumvent the development of abamectin resistance in mites. PMID:28443033

The effect of fermented buckwheat on producing l-carnitine- and γ-aminobutyric acid (GABA)-enriched designer eggs.

PubMed

Park, Namhyeon; Lee, Tae-Kyung; Nguyen, Thi Thanh Hanh; An, Eun-Bae; Kim, Nahyun M; You, Young-Hyun; Park, Tae-Sub; Kim, Doman

2017-07-01

The potential of fermented buckwheat as a feed additive was studied to increase l-carnitine and γ-aminobutyric acid (GABA) in designer eggs. Buckwheat contains high levels of lysine, methionine and glutamate, which are precursors for the synthesis of l-carnitine and GABA. Rhizopus oligosporus was used for the fermentation of buckwheat to produce l-carnitine and GABA that exert positive effects such as enhanced metabolism, antioxidant activities, immunity and blood pressure control. A novel analytical method for simultaneously detecting l-carnitine and GABA was developed using liquid chromatography/mass spectrometry (LC/MS) and LC/MS/MS. The fermented buckwheat extract contained 4 and 34 times more l-carnitine and GABA respectively compared with normal buckwheat. Compared with the control, the fermented buckwheat extract-fed group showed enriched l-carnitine (13.6%) and GABA (8.4%) in the yolk, though only l-carnitine was significantly different (P < 0.05). Egg production (9.4%), albumen weight (2.1%) and shell weight (5.8%) were significantly increased (P < 0.05). There was no significant difference in yolk weight, and total cholesterol (1.9%) and triglyceride (4.9%) in the yolk were lowered (P < 0.05). Fermented buckwheat as a feed additive has the potential to produce l-carnitine- and GABA-enriched designer eggs with enhanced nutrition and homeostasis. These designer eggs pose significant potential to be utilized in superfood production and supplement industries. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Probable gamma-aminobutyric acid involvement in bisphenol A effect at the hypothalamic level in adult male rats.

PubMed

Cardoso, Nancy; Pandolfi, Matías; Lavalle, Justina; Carbone, Silvia; Ponzo, Osvaldo; Scacchi, Pablo; Reynoso, Roxana

2011-12-01

The aim of the present study was to investigate the effects of bisphenol A (BPA) on the neuroendocrine mechanism of control of the reproductive axis in adult male rats exposed to it during pre- and early postnatal periods. Wistar mated rats were treated with either 0.1% ethanol or BPA in their drinking water until their offspring were weaned at the age of 21 days. The estimated average dose of exposure to dams was approximately 2.5 mg/kg body weight per day of BPA. After 21 days, the pups were separated from the mother and sacrificed on 70 day of life. Gn-RH and gamma-aminobutyric acid (GABA) release from hypothalamic fragments was measured. LH, FSH, and testosterone concentrations were determined, and histological and morphometrical studies of testis were performed. Gn-RH release decreased significantly, while GABA serum levels were markedly increased by treatment. LH serum levels showed no changes, and FSH and testosterone levels decreased significantly. Histological studies showed abnormalities in the tubular organization of the germinal epithelium. The cytoarchitecture of germinal cells was apparently normal, and a reduction of the nuclear area of Leydig cells but not their number was observed. Taken all together, these results provide evidence of the effect caused by BPA on the adult male reproductive axis when exposed during pre- and postnatal period. Moreover, our findings suggest a probable GABA involvement in its effect at the hypothalamic level.

High Gama-Aminobutyric Acid Contents Involved in Abamectin Resistance and Predation, an Interesting Phenomenon in Spider Mites.

PubMed

Xu, Zhifeng; Liu, Yanchao; Wei, Peng; Feng, Kaiyang; Niu, Jinzhi; Shen, Guangmao; Lu, Wencai; Xiao, Wei; Wang, Jinjun; Smagghe, Guy J; Xu, Qiang; He, Lin

2017-01-01

Abamectin has been widely used as an insecticide/acaricide for more than 30 years because of its superior bioactivity. Recently, an interesting phenomenon was identified in the carmine spider mite, Tetranychus cinnabarinus , an important pest in agriculture. The gamma aminobutyric acid (GABA) contents in a laboratory abamectin resistant strain of T. cinnabarinus (AbR) were significantly increased. Decreases in activity and mRNA expression of GABA transaminase (GABA-T) were responsible for GABA accumulation in AbR mites. To clarify the mechanism of GABA accumulation mediated abamectin resistance, three artificial approaches were conducted to increase GABA contents in susceptible mites, including feeding of vigabatrin (a specific inhibitor of GABA-T), feeding of exogenous GABA, and inhibition of GABA-T gene expression. The results showed that susceptible mites developed resistance to abamectin when the GABA contents were artificially increased. We also observed that the mites with higher GABA contents moved more slowly, which is consistent with the fact that GABA is an inhibitory neurotransmitter in arthropods. Subsequently, functional response assays revealed that predation rates of predatory mites on GABA accumulated abamectin-resistant mites were much higher than control groups. The tolerance to abamectin, slow crawling speed, and vulnerability to predators were all resulted from GABA accumulation. This relationship between GABA and predation was also confirmed in a field-collected population. Our finding indicates that predatory mites might be used as a tool for biological control to circumvent the development of abamectin resistance in mites.

Transition from androgenic to neurosteroidal action of 5α-androstane-3α, 17β-diol through the type A γ-aminobutyric acid receptor in prostate cancer progression.

PubMed

Xia, Ding; Lai, Doan V; Wu, Weijuan; Webb, Zachary D; Yang, Qing; Zhao, Lichao; Yu, Zhongxin; Thorpe, Jessica E; Disch, Bryan C; Ihnat, Michael A; Jayaraman, Muralidharan; Dhanasekaran, Danny N; Stratton, Kelly L; Cookson, Michael S; Fung, Kar-Ming; Lin, Hsueh-Kung

2018-04-01

Androgen ablation is the standard of care prescribed to patients with advanced or metastatic prostate cancer (PCa) to slow down disease progression. Unfortunately, a majority of PCa patients under androgen ablation progress to castration-resistant prostate cancer (CRPC). Several mechanisms including alternative intra-prostatic androgen production and androgen-independent androgen receptor (AR) activation have been proposed for CRPC progression. Aldo-keto reductase family 1 member C3 (AKR1C3), a multi-functional steroid metabolizing enzyme, is specifically expressed in the cytoplasm of PCa cells; and positive immunoreactivity of the type A γ-aminobutyric acid receptor (GABA A R), an ionotropic receptor and ligand-gated ion channel, is detected on the membrane of PCa cells. We studied a total of 72 radical prostatectomy cases by immunohistochemistry, and identified that 21 cases exhibited positive immunoreactivities for both AKR1C3 and GABA A R. In the dual positive cancer cases, AKR1C3 and GABA A R subunit α 1 were either expressed in the same cells or in neighboring cells. Among several possible substrates, AKR1C3 reduces 5α-dihydrotesterone (DHT) to form 5α-androstane-3α, 17β-diol (3α-diol). 3α-diol is a neurosteroid that acts as a positive allosteric modulator of the GABA A R in the central nervous system (CNS). We examined the hypothesis that 3α-diol-regulated pathological effects in the prostate are GABA A R-dependent, but are independent of the AR. In GABA A R-positive, AR-negative human PCa PC-3 cells, 3α-diol significantly stimulated cell growth in culture and the in ovo chorioallantoic membrane (CAM) xenograft model. 3α-diol also up-regulated expression of the epidermal growth factor (EGF) family of growth factors and activation of EGF receptor (EGFR) and Src as measured by quantitative polymerase chain reaction and immunoblotting, respectively. Inclusion of GABA A R antagonists reversed 3α-diol-stimulated tumor cell growth, expression of EGF

Fatty Acid Biosynthesis Pathways in Methylomicrobium buryatense 5G(B1).

PubMed

Demidenko, Aleksandr; Akberdin, Ilya R; Allemann, Marco; Allen, Eric E; Kalyuzhnaya, Marina G

2016-01-01

Methane utilization by methanotrophic bacteria is an attractive application for biotechnological conversion of natural or biogas into high-added-value products. Haloalcaliphilic methanotrophic bacteria belonging to the genus Methylomicrobium are among the most promising strains for methane-based biotechnology, providing easy and inexpensive cultivation, rapid growth, and the availability of established genetic tools. A number of methane bioconversions using these microbial cultures have been discussed, including the derivation of biodiesel, alkanes, and OMEGA-3 supplements. These compounds are derived from bacterial fatty acid pools. Here, we investigate fatty acid biosynthesis in Methylomicrobium buryatense 5G(B1) . Most of the genes homologous to typical Type II fatty acid biosynthesis pathways could be annotated by bioinformatics analyses, with the exception of fatty acid transport and regulatory elements. Different approaches for improving fatty acid accumulation were investigated. These studies indicated that both fatty acid degradation and acetyl- and malonyl-CoA levels are bottlenecks for higher level fatty acid production. The best strain generated in this study synthesizes 111 ± 2 mg/gDCW of extractable fatty acids, which is ~20% more than the original strain. A candidate gene for fatty acid biosynthesis regulation, farE , was identified and studied. Its deletion resulted in drastic changes to the fatty acid profile, leading to an increased pool of C18-fatty acid methyl ester. The FarE-regulon was further investigated by RNA-seq analysis of gene expression in farE -knockout mutants and farE -overexpressing strains. These gene profiles highlighted a novel set of enzymes and regulators involved in fatty acid biosynthesis. The gene expression and fatty acid profiles of the different farE -strains support the hypothesis that metabolic fluxes upstream of fatty acid biosynthesis restrict fatty acid production in the methanotroph.

Fatty Acid Biosynthesis Pathways in Methylomicrobium buryatense 5G(B1)

PubMed Central

Demidenko, Aleksandr; Akberdin, Ilya R.; Allemann, Marco; Allen, Eric E.; Kalyuzhnaya, Marina G.

2017-01-01

Methane utilization by methanotrophic bacteria is an attractive application for biotechnological conversion of natural or biogas into high-added-value products. Haloalcaliphilic methanotrophic bacteria belonging to the genus Methylomicrobium are among the most promising strains for methane-based biotechnology, providing easy and inexpensive cultivation, rapid growth, and the availability of established genetic tools. A number of methane bioconversions using these microbial cultures have been discussed, including the derivation of biodiesel, alkanes, and OMEGA-3 supplements. These compounds are derived from bacterial fatty acid pools. Here, we investigate fatty acid biosynthesis in Methylomicrobium buryatense 5G(B1). Most of the genes homologous to typical Type II fatty acid biosynthesis pathways could be annotated by bioinformatics analyses, with the exception of fatty acid transport and regulatory elements. Different approaches for improving fatty acid accumulation were investigated. These studies indicated that both fatty acid degradation and acetyl- and malonyl-CoA levels are bottlenecks for higher level fatty acid production. The best strain generated in this study synthesizes 111 ± 2 mg/gDCW of extractable fatty acids, which is ~20% more than the original strain. A candidate gene for fatty acid biosynthesis regulation, farE, was identified and studied. Its deletion resulted in drastic changes to the fatty acid profile, leading to an increased pool of C18-fatty acid methyl ester. The FarE-regulon was further investigated by RNA-seq analysis of gene expression in farE-knockout mutants and farE-overexpressing strains. These gene profiles highlighted a novel set of enzymes and regulators involved in fatty acid biosynthesis. The gene expression and fatty acid profiles of the different farE-strains support the hypothesis that metabolic fluxes upstream of fatty acid biosynthesis restrict fatty acid production in the methanotroph. PMID:28119683

Dopamine Neurons Change the Type of Excitability in Response to Stimuli

PubMed Central

Gutkin, Boris S.; Lapish, Christopher C.; Kuznetsov, Alexey

2016-01-01

The dynamics of neuronal excitability determine the neuron’s response to stimuli, its synchronization and resonance properties and, ultimately, the computations it performs in the brain. We investigated the dynamical mechanisms underlying the excitability type of dopamine (DA) neurons, using a conductance-based biophysical model, and its regulation by intrinsic and synaptic currents. Calibrating the model to reproduce low frequency tonic firing results in N-methyl-D-aspartate (NMDA) excitation balanced by γ-Aminobutyric acid (GABA)-mediated inhibition and leads to type I excitable behavior characterized by a continuous decrease in firing frequency in response to hyperpolarizing currents. Furthermore, we analyzed how excitability type of the DA neuron model is influenced by changes in the intrinsic current composition. A subthreshold sodium current is necessary for a continuous frequency decrease during application of a negative current, and the low-frequency “balanced” state during simultaneous activation of NMDA and GABA receptors. Blocking this current switches the neuron to type II characterized by the abrupt onset of repetitive firing. Enhancing the anomalous rectifier Ih current also switches the excitability to type II. Key characteristics of synaptic conductances that may be observed in vivo also change the type of excitability: a depolarized γ-Aminobutyric acid receptor (GABAR) reversal potential or co-activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) leads to an abrupt frequency drop to zero, which is typical for type II excitability. Coactivation of N-methyl-D-aspartate receptors (NMDARs) together with AMPARs and GABARs shifts the type I/II boundary toward more hyperpolarized GABAR reversal potentials. To better understand how altering each of the aforementioned currents leads to changes in excitability profile of DA neuron, we provide a thorough dynamical analysis. Collectively, these results imply that type I

Conformational distribution of baclofen analogues by 1H and 13C NMR analysis and ab initio HF MO STO-3G or STO-3G* calculations

NASA Astrophysics Data System (ADS)

Vaccher, Claude; Berthelot, Pascal; Debaert, Michel; Vermeersch, Gaston; Guyon, René; Pirard, Bernard; Vercauteren, Daniel P.; Dory, Magdalena; Evrard, Guy; Durant, François

1993-12-01

The conformations of 3-(substituted furan-2-yl) and 3-(substituted thien-2-yl)-γ-aminobutyric acid 1-9 in solution (D 2O) are estimated from high-resolution (300 MHz) 1H NMR coupling data. Conformations and populations of conformers are calculated by means of a modified Karplus-like relationship for the vicinal coupling constants. The results are compared with X-ray crystallographic investigations (torsion angles) and ab initio HF MO ST-3G or STO-3G* calculations. 1H NMR spectral analysis shows how 1-9 in solution retain the preferred g- conformation around the C3C4 bond, as found in the solid state, while a partial rotation is set up around the C2C3 bond: the conformations about C2C3 are all highly populated in solution. The 13C spin-lattice relaxation times are also discussed.

Decreased Phosphorylated Protein Kinase B (Akt) in Individuals with Autism Associated with High Epidermal Growth Factor Receptor (EGFR) and Low Gamma-Aminobutyric Acid (GABA).

PubMed

Russo, Anthony J

2015-01-01

Dysregulation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway could contribute to the pathogenesis of autism spectrum disorders. In this study, phosphorylated Akt concentration was measured in 37 autistic children and 12, gender and age similar neurotypical, controls using an enzyme-linked immunosorbent assay. Akt levels were compared to biomarkers known to be associated with epidermal growth factor receptor (EGFR) and c-Met (hepatocyte growth factor (HGF) receptor) pathways and severity levels of 19 autism-related symptoms. We found phosphorylated Akt levels significantly lower in autistic children and low Akt levels correlated with high EGFR and HGF and low gamma-aminobutyric acid, but not other biomarkers. Low Akt levels also correlated significantly with increased severity of receptive language, conversational language, hypotonia, rocking and pacing, and stimming, These results suggest a relationship between decreased phosphorylated Akt and selected symptom severity in autistic children and support the suggestion that the AKT pathways may be associated with the etiology of autism.

The adjustment of γ-aminobutyric acidA tonic subunits in Huntington's disease: from transcription to translation to synaptic levels into the neostriatum.

PubMed

Rosas-Arellano, Abraham; Estrada-Mondragón, Argel; Mantellero, Carola A; Tejeda-Guzmán, Carlos; Castro, Maite A

2018-04-01

γ-Aminobutyric acid (GABA), plays a key role in all stages of life, also is considered the main inhibitory neurotransmitter. GABA activates two kind of membrane receptors known as GABA A and GABA B , the first one is responsible to render tonic inhibition by pentameric receptors containing α4-6, β3, δ, or ρ1-3 subunits, they are located at perisynaptic and/or in extrasynaptic regions. The biophysical properties of GABA A tonic inhibition have been related with cellular protection against excitotoxic injury and cell death in presence of excessive excitation. On this basis, GABA A tonic inhibition has been proposed as a potential target for therapeutic intervention of Huntington's disease. Huntington's disease is a neurodegenerative disorder caused by a genetic mutation of the huntingtin protein. For experimental studies of Huntington's disease mouse models have been developed, such as R6/1, R6/2, HdhQ92, HdhQ150, as well as YAC128. In all of them, some key experimental reports are focused on neostriatum. The neostriatum is considered as the most important connection between cerebral cortex and basal ganglia structures, its cytology display two pathways called direct and indirect constituted by medium sized spiny neurons expressing dopamine D1 and D2 receptors respectively, they display strong expression of many types of GABA A receptors, including tonic subunits. The studies about of GABA A tonic subunits and Huntington's disease into the neostriatum are rising in recent years, suggesting interesting changes in their expression and localization which can be used as a strategy to delay the cellular damage caused by the imbalance between excitation and inhibition, a hallmark of Huntington's disease.

The adjustment of γ-aminobutyric acidA tonic subunits in Huntington's disease: from transcription to translation to synaptic levels into the neostriatum

PubMed Central

Rosas-Arellano, Abraham; Estrada-Mondragón, Argel; Mantellero, Carola A.; Tejeda-Guzmán, Carlos; Castro, Maite A.

2018-01-01

γ-Aminobutyric acid (GABA), plays a key role in all stages of life, also is considered the main inhibitory neurotransmitter. GABA activates two kind of membrane receptors known as GABAA and GABAB, the first one is responsible to render tonic inhibition by pentameric receptors containing α4−6, β3, δ, or ρ1−3 subunits, they are located at perisynaptic and/or in extrasynaptic regions. The biophysical properties of GABAA tonic inhibition have been related with cellular protection against excitotoxic injury and cell death in presence of excessive excitation. On this basis, GABAA tonic inhibition has been proposed as a potential target for therapeutic intervention of Huntington's disease. Huntington's disease is a neurodegenerative disorder caused by a genetic mutation of the huntingtin protein. For experimental studies of Huntington's disease mouse models have been developed, such as R6/1, R6/2, HdhQ92, HdhQ150, as well as YAC128. In all of them, some key experimental reports are focused on neostriatum. The neostriatum is considered as the most important connection between cerebral cortex and basal ganglia structures, its cytology display two pathways called direct and indirect constituted by medium sized spiny neurons expressing dopamine D1 and D2 receptors respectively, they display strong expression of many types of GABAA receptors, including tonic subunits. The studies about of GABAA tonic subunits and Huntington's disease into the neostriatum are rising in recent years, suggesting interesting changes in their expression and localization which can be used as a strategy to delay the cellular damage caused by the imbalance between excitation and inhibition, a hallmark of Huntington's disease. PMID:29722299

Determination of γ-Aminobutyric Acid (GABA) in Rambutan Fruit cv. Rongrian by HPLC-ELSD and Separation of GABA from Rambutan Fruit Using Dowex 50W-X8 Column.

PubMed

Meeploy, Maneerat; Deewatthanawong, Rujira

2016-03-01

A high-performance liquid chromatography method coupled with an evaporative light scattering detector (ELSD) was validated for the determination of γ-aminobutyric acid (GABA) in rambutan fruit without any sample pretreatment or derivatization. In the concentration range of 0.05-1.0 mg/mL GABA, the ELSD response was linear with a correlation coefficient (r) >0.999. Limit of detection and limit of quantitation were found to be 0.7 and 2.0 µg/mL, respectively. The method enabled the complete separation of GABA in the aqueous extract of rambutan flesh from the impurity peaks at 45.7 min. The recoveries of sample added GABA were obtained in the range of 92.0-99.3%. Intraday and interday relative standard deviations were <5.3%. Repeatability of the extraction process showed the acceptable precision. From the analysis of GABA content in rambutan flesh, 0.71 ± 0.23 mg of GABA was found in 1 g fresh weight. The recovery of GABA after passing through the Dowex 50W-X8 column was 96.65%. The analytical methodology could be potentially applied to the detection and quantification of GABA in other fruits and complex matrices when a sufficient quantity is available. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Fatty acid biosynthesis pathways in Methylomicrobium buryatense 5G(B1)

DOE PAGES

Demidenko, Aleksandr; Akberdin, Ilya R.; Allemann, Marco; ...

2017-01-10

Methane utilization by methanotrophic bacteria is an attractive application for biotechnological conversion of natural or biogas into high-added-value products. Haloalcaliphilic methanotrophic bacteria belonging to the genus Methylomicrobium are among the most promising strains for methane-based biotechnology, providing easy and inexpensive cultivation, rapid growth, and the availability of established genetic tools. A number of methane bioconversions using these microbial cultures have been discussed, including the derivation of biodiesel, alkanes, and OMEGA-3 supplements. These compounds are derived from bacterial fatty acid pools. Here, we investigate fatty acid biosynthesis in Methylomicrobium buryatense 5G(B1). Most of the genes homologous to typical Type II fattymore » acid biosynthesis pathways could be annotated by bioinformatics analyses, with the exception of FA transport and regulatory elements. Different approaches for improving fatty acid accumulation were investigated. These studies indicated that both fatty acid degradation and acetyl- and malonyl-CoA levels are bottlenecks for higher level fatty acid production. The best strain generated in this study synthesizes 111 ± 2 mg/gDCW of extractable fatty acids, which is ~20% more than the original strain. A candidate gene for FA-biosynthesis regulation, farE, was identified and studied. Its deletion resulted in drastic changes to the FA profile, leading to an increased pool of C18-fatty acid methyl ester. The FarE-regulon was further investigated by RNA-seq analysis of gene expression in farE-knockout mutants and farE-overexpressing strains. These gene profiles highlighted a novel set of enzymes and regulators involved in fatty acid biosynthesis. As a result, the gene expression and fatty acid profiles of the different farE-strains support the hypothesis that metabolic fluxes upstream of fatty acid biosynthesis restrict fatty acid production in the methanotroph.« less

Fatty acid biosynthesis pathways in Methylomicrobium buryatense 5G(B1)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demidenko, Aleksandr; Akberdin, Ilya R.; Allemann, Marco

Methane utilization by methanotrophic bacteria is an attractive application for biotechnological conversion of natural or biogas into high-added-value products. Haloalcaliphilic methanotrophic bacteria belonging to the genus Methylomicrobium are among the most promising strains for methane-based biotechnology, providing easy and inexpensive cultivation, rapid growth, and the availability of established genetic tools. A number of methane bioconversions using these microbial cultures have been discussed, including the derivation of biodiesel, alkanes, and OMEGA-3 supplements. These compounds are derived from bacterial fatty acid pools. Here, we investigate fatty acid biosynthesis in Methylomicrobium buryatense 5G(B1). Most of the genes homologous to typical Type II fattymore » acid biosynthesis pathways could be annotated by bioinformatics analyses, with the exception of FA transport and regulatory elements. Different approaches for improving fatty acid accumulation were investigated. These studies indicated that both fatty acid degradation and acetyl- and malonyl-CoA levels are bottlenecks for higher level fatty acid production. The best strain generated in this study synthesizes 111 ± 2 mg/gDCW of extractable fatty acids, which is ~20% more than the original strain. A candidate gene for FA-biosynthesis regulation, farE, was identified and studied. Its deletion resulted in drastic changes to the FA profile, leading to an increased pool of C18-fatty acid methyl ester. The FarE-regulon was further investigated by RNA-seq analysis of gene expression in farE-knockout mutants and farE-overexpressing strains. These gene profiles highlighted a novel set of enzymes and regulators involved in fatty acid biosynthesis. As a result, the gene expression and fatty acid profiles of the different farE-strains support the hypothesis that metabolic fluxes upstream of fatty acid biosynthesis restrict fatty acid production in the methanotroph.« less

Targeted enhancement of glutamate-to-γ-aminobutyrate conversion in Arabidopsis seeds affects carbon-nitrogen balance and storage reserves in a development-dependent manner.

PubMed

Fait, Aaron; Nesi, Adriano Nunes; Angelovici, Ruthie; Lehmann, Martin; Pham, Phuong Anh; Song, Luhua; Haslam, Richard P; Napier, Johnathan A; Galili, Gad; Fernie, Alisdair R

2011-11-01

In seeds, glutamate decarboxylase (GAD) operates at the metabolic nexus between carbon and nitrogen metabolism by catalyzing the unidirectional decarboxylation of glutamate to form γ-aminobutyric acid (GABA). To elucidate the regulatory role of GAD in seed development, we generated Arabidopsis (Arabidopsis thaliana) transgenic plants expressing a truncated GAD from Petunia hybrida missing the carboxyl-terminal regulatory Ca(2+)-calmodulin-binding domain under the transcriptional regulation of the seed maturation-specific phaseolin promoter. Dry seeds of the transgenic plants accumulated considerable amounts of GABA, and during desiccation the content of several amino acids increased, although not glutamate or proline. Dry transgenic seeds had higher protein content than wild-type seeds but lower amounts of the intermediates of glycolysis, glycerol and malate. The total fatty acid content of the transgenic seeds was 50% lower than in the wild type, while acyl-coenzyme A accumulated in the transgenic seeds. Labeling experiments revealed altered levels of respiration in the transgenic seeds, and fractionation studies indicated reduced incorporation of label in the sugar and lipid fractions extracted from transgenic seeds. Comparative transcript profiling of the dry seeds supported the metabolic data. Cellular processes up-regulated at the transcript level included the tricarboxylic acid cycle, fatty acid elongation, the shikimate pathway, tryptophan metabolism, nitrogen-carbon remobilization, and programmed cell death. Genes involved in the regulation of germination were similarly up-regulated. Taken together, these results indicate that the GAD-mediated conversion of glutamate to GABA during seed development plays an important role in balancing carbon and nitrogen metabolism and in storage reserve accumulation.

Sodium p-Aminosalicylic Acid Reverses Sub-Chronic Manganese-Induced Impairments of Spatial Learning and Memory Abilities in Rats, but Fails to Restore γ-Aminobutyric Acid Levels.

PubMed

Li, Shao-Jun; Ou, Chao-Yan; He, Sheng-Nan; Huang, Xiao-Wei; Luo, Hai-Lan; Meng, Hao-Yang; Lu, Guo-Dong; Jiang, Yue-Ming; Vieira Peres, Tanara; Luo, Yi-Ni; Deng, Xiang-Fa

2017-04-10

Excessive manganese (Mn) exposure is not only a health risk for occupational workers, but also for the general population. Sodium para-aminosalicylic acid (PAS-Na) has been successfully used in the treatment of manganism, but the involved molecular mechanisms have yet to be determined. The present study aimed to investigate the effects of PAS-Na on sub-chronic Mn exposure-induced impairments of spatial learning and memory, and determine the possible involvements of γ-aminobutyric acid (GABA) metabolism in vivo. Sprague-Dawley male rats received daily intraperitoneal injections MnCl₂ (as 6.55 mg/kg Mn body weight, five days per week for 12 weeks), followed by daily subcutaneous injections of 100, 200, or 300 mg/kg PAS-Na for an additional six weeks. Mn exposure significantly impaired spatial learning and memory ability, as noted in the Morris water maze test, and the following PAS-Na treatment successfully restored these adverse effects to levels indistinguishable from controls. Unexpectedly, PAS-Na failed to recover the Mn-induced decrease in the overall GABA levels, although PAS-Na treatment reversed Mn-induced alterations in the enzyme activities directly responsible for the synthesis and degradation of GABA (glutamate decarboxylase and GABA-transaminase, respectively). Moreover, Mn exposure caused an increase of GABA transporter 1 (GAT-1) and decrease of GABA A receptor (GABA A ) in transcriptional levels, which could be reverted by the highest dose of 300 mg/kg PAS-Na treatment. In conclusion, the GABA metabolism was interrupted by sub-chronic Mn exposure. However, the PAS-Na treatment mediated protection from sub-chronic Mn exposure-induced neurotoxicity, which may not be dependent on the GABA metabolism.

Sodium p-Aminosalicylic Acid Reverses Sub-Chronic Manganese-Induced Impairments of Spatial Learning and Memory Abilities in Rats, but Fails to Restore γ-Aminobutyric Acid Levels

PubMed Central

Li, Shao-Jun; Ou, Chao-Yan; He, Sheng-Nan; Huang, Xiao-Wei; Luo, Hai-Lan; Meng, Hao-Yang; Lu, Guo-Dong; Jiang, Yue-Ming; Vieira Peres, Tanara; Luo, Yi-Ni; Deng, Xiang-Fa

2017-01-01

Excessive manganese (Mn) exposure is not only a health risk for occupational workers, but also for the general population. Sodium para-aminosalicylic acid (PAS-Na) has been successfully used in the treatment of manganism, but the involved molecular mechanisms have yet to be determined. The present study aimed to investigate the effects of PAS-Na on sub-chronic Mn exposure-induced impairments of spatial learning and memory, and determine the possible involvements of γ-aminobutyric acid (GABA) metabolism in vivo. Sprague-Dawley male rats received daily intraperitoneal injections MnCl2 (as 6.55 mg/kg Mn body weight, five days per week for 12 weeks), followed by daily subcutaneous injections of 100, 200, or 300 mg/kg PAS-Na for an additional six weeks. Mn exposure significantly impaired spatial learning and memory ability, as noted in the Morris water maze test, and the following PAS-Na treatment successfully restored these adverse effects to levels indistinguishable from controls. Unexpectedly, PAS-Na failed to recover the Mn-induced decrease in the overall GABA levels, although PAS-Na treatment reversed Mn-induced alterations in the enzyme activities directly responsible for the synthesis and degradation of GABA (glutamate decarboxylase and GABA-transaminase, respectively). Moreover, Mn exposure caused an increase of GABA transporter 1 (GAT-1) and decrease of GABA A receptor (GABAA) in transcriptional levels, which could be reverted by the highest dose of 300 mg/kg PAS-Na treatment. In conclusion, the GABA metabolism was interrupted by sub-chronic Mn exposure. However, the PAS-Na treatment mediated protection from sub-chronic Mn exposure-induced neurotoxicity, which may not be dependent on the GABA metabolism. PMID:28394286

Channel opening of gamma-aminobutyric acid receptor from rat brain: molecular mechanisms of the receptor responses.

PubMed

Cash, D J; Subbarao, K

1987-12-01

The function of gamma-aminobutyric acid (GABA) receptors, which mediate transmembrane chloride flux, can be studied by use of 36Cl- isotope tracer with membrane from mammalian brain by quench-flow technique, with reaction times that allow resolution of the receptor desensitization rates from the ion flux rates. The rates of chloride exchange into the vesicles in the absence and presence of GABA were characterized with membrane from rat cerebral cortex. Unspecific 36Cl- influx was completed in three phases of ca. 3% (t 1/2 = 0.6 s), 56% (t 1/2 = 82 s), and 41% (t 1/2 = 23 min). GABA-mediated, specific chloride exchange occurred with 6.5% of the total vesicular internal volume. The GABA-dependent 36Cl- influx proceeded in two phases, each progressively slowed by desensitization. The measurements supported the presence of two distinguishable active GABA receptors on the same membrane mediating chloride exchange into the vesicles with initial first-order rate constants of 9.5 s-1 and 2.3 s-1 and desensitizing with first-order rate constants of 21 s-1 and 1.4 s-1, respectively, at saturation. The half-response concentrations were similar for both receptors, 150 microM and 114 microM GABA for desensitization and 105 microM and 82 microM for chloride exchange, for the faster and slower desensitizing receptors, respectively. The two receptors were present in the activity ratio of ca. 4/1, similar to the ratio of "low-affinity" to "high-affinity" GABA sites found in ligand binding experiments. The desensitization rates have a different dependence on GABA concentration than the channel-opening equilibria.(ABSTRACT TRUNCATED AT 250 WORDS)

In Vivo Dentate Nucleus Gamma-aminobutyric Acid Concentration in Essential Tremor vs. Controls.

PubMed

Louis, Elan D; Hernandez, Nora; Dyke, Jonathan P; Ma, Ruoyun E; Dydak, Ulrike

2018-04-01

Despite its high prevalence, essential tremor (ET) is among the most poorly understood neurological diseases. The presence and extent of Purkinje cell (PC) loss in ET is the subject of controversy. PCs are a major storehouse of central nervous system gamma-aminobutyric acid (GABA), releasing GABA at the level of the dentate nucleus. It is therefore conceivable that cerebellar dentate nucleus GABA concentration could be an in vivo marker of PC number. We used in vivo 1 H magnetic resonance spectroscopy (MRS) to quantify GABA concentrations in two cerebellar volumes of interest, left and right, which included the dentate nucleus, comparing 45 ET cases to 35 age-matched controls. 1 H MRS was performed using a 3.0-T Siemens Tim Trio scanner. The MEGA-PRESS J-editing sequence was used for GABA detection in two cerebellar volumes of interest (left and right) that included the dentate nucleus. The two groups did not differ with respect to our primary outcome of GABA concentration (given in institutional units). For the right dentate nucleus, [GABA] in ET cases = 2.01 ± 0.45 and [GABA] in controls = 1.86 ± 0.53, p = 0.17. For the left dentate nucleus, [GABA] in ET cases = 1.68 ± 0.49 and [GABA] controls = 1.80 ± 0.53, p = 0.33. The controls had similar dentate nucleus [GABA] in the right vs. left dentate nucleus (p = 0.52); however, in ET cases, the value on the right was considerably higher than that on the left (p = 0.001). We did not detect a reduction in dentate nucleus GABA concentration in ET cases vs. One interpretation of the finding is that it does not support the existence of PC loss in ET; however, an alternative interpretation is the observed pattern could be due to the effects of terminal sprouting in ET (i.e., collateral sprouting from surviving PCs making up for the loss of GABA-ergic terminals from PC degeneration). Further research is needed.

Endogenous gamma-aminobutyric acid modulates tonic guinea pig airway tone and propofol-induced airway smooth muscle relaxation.

PubMed

Gallos, George; Gleason, Neil R; Virag, Laszlo; Zhang, Yi; Mizuta, Kentaro; Whittington, Robert A; Emala, Charles W

2009-04-01

Emerging evidence indicates that an endogenous autocrine/paracrine system involving gamma-aminobutyric acid (GABA) is present in airways. GABAA channels, GABAB receptors, and the enzyme that synthesizes GABA have been identified in airway epithelium and smooth muscle. However, the endogenous ligand itself, GABA, has not been measured in airway tissues. The authors sought to demonstrate that GABA is released in response to contractile agonists and tonically contributes a prorelaxant component to contracted airway smooth muscle. The amount and cellular localization of GABA in upper guinea pig airways under resting and contracted tone was determined by high pressure liquid chromatography and immunohistochemistry, respectively. The contribution that endogenous GABA imparts on the maintenance of airway smooth muscle acetylcholine-induced contraction was assessed in intact guinea pig airway tracheal rings using selective GABAA antagonism (gabazine) under resting or acetylcholine-contracted conditions. The ability of an allosteric agent (propofol) to relax a substance P-induced relaxation in an endogenous GABA-dependent manner was assessed. GABA levels increased and localized to airway smooth muscle after contractile stimuli in guinea pig upper airways. Acetylcholine-contracted guinea pig tracheal rings exhibited an increase in contracted force upon addition of the GABAA antagonist gabazine that was subsequently reversed by the addition of the GABAA agonist muscimol. Propofol dose-dependently relaxed a substance P contraction that was blocked by gabazine. These studies demonstrate that GABA is endogenously present and increases after contractile stimuli in guinea pig upper airways and that endogenous GABA contributes a tonic prorelaxant component in the maintenance of airway smooth muscle tone.

Endogenous γ-aminobutyric Acid Modulates Tonic Guinea Pig Airway Tone and Propofol-induced Airway Smooth Muscle Relaxation

PubMed Central

Gallos, George; Gleason, Neil R.; Virag, Laszlo; Zhang, Yi; Mizuta, Kentauro; Whittington, Robert A.; Emala, Charles W.

2009-01-01

Background Emerging evidence indicates that an endogenous autocrine/paracrine system involving γ-aminobutyric acid (GABA) is present in airways. GABAA channels, GABAB receptors and the enzyme that synthesizes GABA have been identified in airway epithelium and smooth muscle. However, the endogenous ligand itself, GABA, has not been measured in airway tissues. We sought to demonstrate that GABA is released in response to contractile agonists and tonically contributes a pro-relaxant component to contracted airway smooth muscle. Methods The amount and cellular localization of GABA in upper guinea pig airways under resting and contracted tone was determined by high pressure liquid chromatography and immunohistochemistry, respectively. The contribution that endogenous GABA imparts on the maintenance of airway smooth muscle acetylcholine-induced contraction was assessed in intact guinea pig airway tracheal rings using selective GABAA antagonism (gabazine) under resting or acetylcholine-contracted conditions. The ability of an allosteric agent (propofol) to relax a substance P-induced relaxation in an endogenous GABA-dependent manner was assessed. Results GABA levels increased and localized to airway smooth muscle following contractile stimuli in guinea pig upper airways. Acetylcholine-contracted guinea pig tracheal rings exhibited an increase in contracted force upon addition of the GABAA antagonist gabazine which was subsequently reversed by the addition of the GABAA agonist muscimol. Propofol dose-dependently relaxed a substance P contraction that was blocked by gabazine. Conclusion These studies demonstrate that GABA is endogenously present and increases following contractile stimuli in guinea pig upper airways and that endogenous GABA contributes a tonic pro-relaxant component in the maintenance of airway smooth muscle tone. PMID:19322939

Characterising the Role of GABA and Its Metabolism in the Wheat Pathogen Stagonospora nodorum

PubMed Central

Mead, Oliver; Thynne, Eli; Winterberg, Britta; Solomon, Peter S.

2013-01-01

A reverse genetics approach was used to investigate the role of γ-aminobutyric acid metabolism in the wheat pathogenic fungus Stagonospora nodorum. The creation of mutants lacking Sdh1, the gene encoding succinic semialdehyde dehydrogenase, resulted in strains that grew poorly on γ-aminobutyric acid as a nitrogen source. The sdh1 mutants were more susceptible to reactive oxygen stress but were less affected by increased growth temperatures. Pathogenicity assays revealed that the metabolism of γ-aminobutyric acid is required for complete pathogenicity. Growth assays of the wild-type and mutant strains showed that the inclusion of γ-aminobutyric acid as a supplement in minimal media (i.e., not as a nitrogen or carbon source) resulted in restricted growth but increased sporulation. The addition of glutamate, the precursor to GABA, had no effect on either growth or sporulation. The γ-aminobutyric acid effect on sporulation was found to be dose dependent and not restricted to Stagonospora nodorum with a similar effect observed in the dothideomycete Botryosphaeria sp. The positive effect on sporulation was assayed using isomers of γ-aminobutyric acid and other metabolites known to influence asexual development in Stagonospora nodorum but no effect was observed. These data demonstrate that γ-aminobutyric acid plays an important role in Stagonospora nodorum in responding to environmental stresses while also having a positive effect on asexual development. PMID:24265684

Production and Its Anti-hyperglycemic Effects of γ-Aminobutyric Acid from the Wild Yeast Strain Pichia silvicola UL6-1 and Sporobolomyces carnicolor 402-JB-1.

PubMed

Han, Sang-Min; Lee, Jong-Soo

2017-09-01

This study was done to produce γ-aminobutyric acid (GABA) from wild yeast as well as investigate its anti-hyperglycemic effects. Among ten GABA-producing yeast strains, Pichia silvicola UL6-1 and Sporobolomyces carnicolor 402-JB-1 produced high GABA concentration of 134.4 µg/mL and 179.2 µg/mL, respectively. P. silvicola UL6-1 showed a maximum GABA yield of 136.5 µg/mL and 200.8 µg/mL from S. carnicolor 402-JB-1 when they were cultured for 30 hr at 30℃ in yeast extract-peptone-dextrose medium. The cell-free extract from P. silvicola UL6-1 and S. carnicolor 402-JB-1 showed very high anti-hyperglycemic α-glucosidase inhibitory activity of 72.3% and 69.9%, respectively. Additionally, their cell-free extract-containing GABA showed the anti-hyperglycemic effect in streptozotocin-induced diabetic Sprague-Dawley rats.

Posterior cingulate γ-aminobutyric acid and glutamate/glutamine are reduced in amnestic mild cognitive impairment and are unrelated to amyloid deposition and apolipoprotein E genotype

PubMed Central

Riese, Florian; Gietl, Anton; Zölch, Niklaus; Henning, Anke; O’Gorman, Ruth; Kälin, Andrea M.; Leh, Sandra E.; Buck, Alfred; Warnock, Geoffrey; Edden, Richard A.E.; Luechinger, Roger; Hock, Christoph; Kollias, Spyros; Michels, Lars

2017-01-01

The biomarker potential of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) for the in vivo characterization of preclinical stages in Alzheimer’s disease has not yet been explored. We measured GABA, glutamate + glutamine (Glx), and N-acetyl-aspartate (NAA) levels by single-voxel MEGA-PRESS magnetic resonance spectroscopy in the posterior cingulate cortex of 21 elderly subjects and 15 patients with amnestic mild cognitive impairment. Participants underwent Pittsburgh Compound B positron emission tomography, apolipoprotein E (APOE) genotyping, and neuropsychological examination. GABA, Glx, and NAA levels were significantly lower in patients. NAA was lower in Pittsburgh Compound B-positive subjects and APOE ε4 allele carriers. GABA, Glx, and NAA levels were positively correlated to CERAD word learning scores. Reductions in GABA, Glx, and NAA levels may serve as metabolic biomarkers for cognitive impairment in amnestic mild cognitive impairment. Because GABA and Glx do not seem to reflect amyloid β deposition or APOE genotype, they are less likely biomarker candidates for preclinical Alzheimer’s disease. PMID:25169676

Reduced γ-Aminobutyric Acid and Glutamate+Glutamine Levels in Drug-Naïve Patients with First-Episode Schizophrenia but Not in Those at Ultrahigh Risk

PubMed Central

Tang, Yingying; Zhang, Tianhong; Cui, Huiru; Xu, Lihua; Zeng, Botao; Li, Yu; Li, Gaiying; Li, Chunbo; Liu, Hui; Zhang, Jianye

2016-01-01

Altered γ-aminobutyric acid (GABA), glutamate (Glu) levels, and an imbalance between GABAergic and glutamatergic neurotransmissions have been involved in the pathophysiology of schizophrenia. However, it remains unclear how these abnormalities impact the onset and course of psychosis. In the present study, 21 drug-naïve subjects at ultrahigh risk for psychosis (UHR), 16 drug-naïve patients with first-episode schizophrenia (FES), and 23 healthy controls (HC) were enrolled. In vivo GABA and glutamate+glutamine (Glx) levels in the medial prefrontal cortex were measured using proton magnetic resonance spectroscopy. Medial prefrontal GABA and Glx levels in FES patients were significantly lower than those in HC and UHR, respectively. GABA and Glx levels in UHR were comparable with those in HC. In each group, there was a positive correlation between GABA and Glx levels. Reduced medial prefrontal GABA and Glx levels thus may play an important role in the early stages of schizophrenia. PMID:28003912

Reduced γ-Aminobutyric Acid and Glutamate+Glutamine Levels in Drug-Naïve Patients with First-Episode Schizophrenia but Not in Those at Ultrahigh Risk.

PubMed

Wang, Junjie; Tang, Yingying; Zhang, Tianhong; Cui, Huiru; Xu, Lihua; Zeng, Botao; Li, Yu; Li, Gaiying; Li, Chunbo; Liu, Hui; Lu, Zheng; Zhang, Jianye; Wang, Jijun

2016-01-01

Altered γ -aminobutyric acid (GABA), glutamate (Glu) levels, and an imbalance between GABAergic and glutamatergic neurotransmissions have been involved in the pathophysiology of schizophrenia. However, it remains unclear how these abnormalities impact the onset and course of psychosis. In the present study, 21 drug-naïve subjects at ultrahigh risk for psychosis (UHR), 16 drug-naïve patients with first-episode schizophrenia (FES), and 23 healthy controls (HC) were enrolled. In vivo GABA and glutamate+glutamine (Glx) levels in the medial prefrontal cortex were measured using proton magnetic resonance spectroscopy. Medial prefrontal GABA and Glx levels in FES patients were significantly lower than those in HC and UHR, respectively. GABA and Glx levels in UHR were comparable with those in HC. In each group, there was a positive correlation between GABA and Glx levels. Reduced medial prefrontal GABA and Glx levels thus may play an important role in the early stages of schizophrenia.

Salicylic acid deficiency in NahG transgenic lines and sid2 mutants increases seed yield in the annual plant Arabidopsis thaliana

PubMed Central

Abreu, Maria Elizabeth; Munné-Bosch, Sergi

2009-01-01

Salicylic acid-deficient NahG transgenic lines and sid2 mutants were used to evaluate the role of this compound in the development of the short-lived, annual plant Arabidopsis thaliana, with a particular focus on the interplay between salicylic acid and other phytohormones. Low salicylic acid levels led to increased growth, as well as to smaller abscisic acid levels and reduced damage to PSII (as indicated by Fv/Fm ratios) during the reproductive stages in rosette leaves of NahG transgenic lines and sid2 mutants, compared with wild-type plants. Furthermore, salicylic acid deficiency highly influenced seed yield and composition. Seed production increased by 4.4-fold and 3.5-fold in NahG transgenic lines and sid2 mutants, respectively, compared to the wild type. Salicylic acid deficiency also improved seed composition in terms of antioxidant vitamin concentrations, seeds of salicylic acid-deficient plants showing higher levels of α- and γ-tocopherol (vitamin E) and β-carotene (pro-vitamin A) than seeds of wild-type plants. Seeds of salicylic acid-deficient plants also showed higher nitrogen concentrations than seeds of wild-type plants. It is concluded that (i) the sid2 gene, which encodes for isochorismate synthase, plays a central role in salicylic acid biosynthesis during plant development in A. thaliana, (ii) salicylic acid plays a role in the regulation of growth, senescence, and seed production, (iii) there is a cross-talk between salicylic acid and other phytohormones during plant development, and (iv) the concentrations of antioxidant vitamins in seeds may be influenced by the endogenous levels of salicylic acid in plants. PMID:19188277

Seasonal changes in amino acids, protein and total nitrogen in needles of fertilized Scots pine trees.

PubMed

Näsholm, T; Ericsson, A

1990-09-01

Seasonal changes in amino acids, protein and total nitrogen in needles of 30-year-old, fertilized Scots pine (Pinus sylvestris L.) trees growing in Northern Sweden were investigated over two years in field experiments. The studied plots had been fertilized annually for 17 years with (i) a high level of N, (ii) a medium level of N, or (iii) a medium level of N, P and K. Trees growing on unfertilized plots served as controls. In control trees, glutamine, glutamic acid, gamma-aminobutyric acid, aspartic acid and proline represented 50-70% of the total free amino acids determined. Arginine was present only in low concentrations in control trees throughout the year, but it was usually the most abundant amino acid in fertilized trees. Glutamine concentrations were high during the spring and summer in both years of study, whereas proline concentrations were high in the spring but otherwise low throughout the year. In the first year of study, glutamic acid concentrations were high during the spring and summer, whereas gamma-aminobutyric acid was present in high concentrations during the winter months. This pattern was less pronounced in the second year of investigation. The concentrations of most amino acids, except glutamic acid, increased in response to fertilization. Nitrogen fertilization increased the foliar concentration of arginine from < 1 micromol g(dw) (-1) in control trees to a maximum of 110 micromol g(dw) (-1). Trees fertilized with nitrogen, phosphorus and potassium had significantly lower arginine concentrations than trees fertilized with the same amount of nitrogen only. Protein concentrations were similar in all fertilized trees but higher than those in control trees. For all treatments, protein concentrations were high in winter and at a minimum in early spring. In summer, the protein concentration remained almost constant except for a temporary decrease which coincided with the expansion of new shoots. Apart from arginine, the amino acid composition of

Activating glutamate decarboxylase activity by removing the autoinhibitory domain leads to hyper γ-aminobutyric acid (GABA) accumulation in tomato fruit.

PubMed

Takayama, Mariko; Matsukura, Chiaki; Ariizumi, Tohru; Ezura, Hiroshi

2017-01-01

The C-terminal extension region of SlGAD3 is likely involved in autoinhibition, and removing this domain increases GABA levels in tomato fruits. γ-Aminobutyric acid (GABA) is a ubiquitous non-protein amino acid with several health-promoting benefits. In many plants including tomato, GABA is synthesized via decarboxylation of glutamate in a reaction catalyzed by glutamate decarboxylase (GAD), which generally contains a C-terminal autoinhibitory domain. We previously generated transgenic tomato plants in which tomato GAD3 (SlGAD3) was expressed using the 35S promoter/NOS terminator expression cassette (35S-SlGAD3-NOS), yielding a four- to fivefold increase in GABA levels in red-ripe fruits compared to the control. In this study, to further increase GABA accumulation in tomato fruits, we expressed SlGAD3 with (SlGAD3 OX ) or without (SlGAD3ΔC OX ) a putative autoinhibitory domain in tomato using the fruit ripening-specific E8 promoter and the Arabidopsis heat shock protein 18.2 (HSP) terminator. Although the GABA levels in SlGAD3 OX fruits were equivalent to those in 35S-SlGAD3-NOS fruits, GABA levels in SlGAD3ΔC OX fruits increased by 11- to 18-fold compared to control plants, indicating that removing the autoinhibitory domain increases GABA biosynthesis activity. Furthermore, the increased GABA levels were accompanied by a drastic reduction in glutamate and aspartate levels, indicating that enhanced GABA biosynthesis affects amino acid metabolism in ripe-fruits. Moreover, SlGAD3ΔC OX fruits exhibited an orange-ripe phenotype, which was associated with reduced levels of both carotenoid and mRNA transcripts of ethylene-responsive carotenogenic genes, suggesting that over activation of GAD influences ethylene sensitivity. Our strategy utilizing the E8 promoter and HSP terminator expression cassette, together with SlGAD3 C-terminal deletion, would facilitate the production of tomato fruits with increased GABA levels.

Predicting Thermodynamic Behaviors of Non-Protein Amino Acids as a Function of Temperature and pH

NASA Astrophysics Data System (ADS)

Kitadai, Norio

2016-03-01

Why does life use α-amino acids exclusively as building blocks of proteins? To address that fundamental question from an energetic perspective, this study estimated the standard molal thermodynamic data for three non-α-amino acids (β-alanine, γ-aminobutyric acid, and ɛ-aminocaproic acid) and α-amino- n-butyric acid in their zwitterionic, negative, and positive ionization states based on the corresponding experimental measurements reported in the literature. Temperature dependences of their heat capacities were described based on the revised Helgeson-Kirkham-Flowers (HKF) equations of state. The obtained dataset was then used to calculate the standard molal Gibbs energies ( ΔG o) of the non-α-amino acids as a function of temperature and pH. Comparison of their ΔG o values with those of α-amino acids having the same molecular formula showed that the non-α-amino acids have similar ΔG o values to the corresponding α-amino acids in physiologically relevant conditions (neutral pH, <100 °C). In acidic and alkaline pH, the non-α-amino acids are thermodynamically more stable than the corresponding α-ones over a broad temperature range. These results suggest that the energetic cost of synthesis is not an important selection pressure to incorporate α-amino acids into biological systems.

Predicting Thermodynamic Behaviors of Non-Protein Amino Acids as a Function of Temperature and pH.

PubMed

Kitadai, Norio

2016-03-01

Why does life use α-amino acids exclusively as building blocks of proteins? To address that fundamental question from an energetic perspective, this study estimated the standard molal thermodynamic data for three non-α-amino acids (β-alanine, γ-aminobutyric acid, and ε-aminocaproic acid) and α-amino-n-butyric acid in their zwitterionic, negative, and positive ionization states based on the corresponding experimental measurements reported in the literature. Temperature dependences of their heat capacities were described based on the revised Helgeson-Kirkham-Flowers (HKF) equations of state. The obtained dataset was then used to calculate the standard molal Gibbs energies (∆G (o)) of the non-α-amino acids as a function of temperature and pH. Comparison of their ∆G (o) values with those of α-amino acids having the same molecular formula showed that the non-α-amino acids have similar ∆G (o) values to the corresponding α-amino acids in physiologically relevant conditions (neutral pH, <100 °C). In acidic and alkaline pH, the non-α-amino acids are thermodynamically more stable than the corresponding α-ones over a broad temperature range. These results suggest that the energetic cost of synthesis is not an important selection pressure to incorporate α-amino acids into biological systems.

In vivo magnetic resonance spectroscopy measurement of gray-matter and white-matter gamma-aminobutyric acid concentration in sensorimotor cortex using a motion-controlled MEGA point-resolved spectroscopy sequence.

PubMed

Bhattacharyya, Pallab K; Phillips, Micheal D; Stone, Lael A; Lowe, Mark J

2011-04-01

Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the brain. Understanding the GABA concentration, in vivo, is important to understand normal brain function. Using MEGA point-resolved spectroscopy sequence with interleaved water scans to detect subject motion, GABA level of sensorimotor cortex was measured using a voxel identified from a functional magnetic resonance imaging scan. The GABA level in a 20×20×20-mm(3) voxel consisting of 37%±7% gray matter, 52%±12% white matter and 11%±8% cerebrospinal fluid in the sensorimotor region was measured to be 1.43±0.48 mM. In addition, using linear regression analysis, GABA concentrations within gray and white matter were calculated to be 2.87±0.61 and 0.33±0.11 mM, respectively. Copyright © 2011 Elsevier Inc. All rights reserved.

Effect of Γ-aminobutyric acid on kidney injury induced by renal ischemia-reperfusion in male and female rats: Gender-related difference.

PubMed

Vafapour, Marzieh; Nematbakhsh, Mehdi; Monajemi, Ramesh; Mazaheri, Safoora; Talebi, Ardeshir; Talebi, Nahid; Shirdavani, Soheyla

2015-01-01

The most important cause of kidney injury is renal ischemia/reperfusion injury (IRI), which is gender-related. This study was designed to investigate the protective role of Γ-aminobutyric acid (GABA (against IRI in male and female rats. Thirty-six female and male wistar rats were assigned to six experimental groups. The IRI was induced by clamping renal vessels for 45 min then was performed reperfusion for 24 h. The group sex posed to IRI were pretreated with GABA and were compared with the control groups. Serum levels of creatinine and blood urea nitrogen, kidney weight, and kidney tissue damage score increased in the IRI alone groups, (P < 0.05), while GABA decreased these parameters in female significantly (P < 0.05), but not in male rats. Uterus weight decreased significantly in female rats treated with GABA. Testis weight did not alter in male rats. Serum level of nitrite and kidney level of malondialdehyde (MDA) had no significant change in both female and male rats. Kidney level of nitrite increased significantly in female rats experienced IRI and serum level of MDA increased significantly in males that were exposed to IRI (P < 0.05). GABA could ameliorate kidney injury induced by renal IRI in a gender dependent manner.

γ-Aminobutyric Acid Imparts Partial Protection from Salt Stress Injury to Maize Seedlings by Improving Photosynthesis and Upregulating Osmoprotectants and Antioxidants

PubMed Central

Wang, Yongchao; Gu, Wanrong; Meng, Yao; Xie, Tenglong; Li, Lijie; Li, Jing; Wei, Shi

2017-01-01

γ-Aminobutyric acid (GABA) has high physiological activity in plant stress physiology. This study showed that the application of exogenous GABA by root drenching to moderately (MS, 150 mM salt concentration) and severely salt-stressed (SS, 300 mM salt concentration) plants significantly increased endogenous GABA concentration and improved maize seedling growth but decreased glutamate decarboxylase (GAD) activity compared with non-treated ones. Exogenous GABA alleviated damage to membranes, increased in proline and soluble sugar content in leaves, and reduced water loss. After the application of GABA, maize seedling leaves suffered less oxidative damage in terms of superoxide anion (O2·−) and malondialdehyde (MDA) content. GABA-treated MS and SS maize seedlings showed increased enzymatic antioxidant activity compared with that of untreated controls, and GABA-treated MS maize seedlings had a greater increase in enzymatic antioxidant activity than SS maize seedlings. Salt stress severely damaged cell function and inhibited photosynthesis, especially in SS maize seedlings. Exogenous GABA application could reduce the accumulation of harmful substances, help maintain cell morphology, and improve the function of cells during salt stress. These effects could reduce the damage to the photosynthetic system from salt stress and improve photosynthesis and chlorophyll fluorescence parameters. GABA enhanced the salt tolerance of maize seedlings. PMID:28272438

A functional assay to measure postsynaptic gamma-aminobutyric acidB responses in cultured spinal cord neurons: Heterologous regulation of the same K+ channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamatchi, G.L.; Ticku, M.K.

1991-02-01

The stimulation of postsynaptic gamma-aminobutyric acid (GABA)B receptors leads to slow inhibitory postsynaptic potentials due to the influx of K(+)-ions. This was studied biochemically, in vitro in mammalian cultured spinal cord neurons by using 86Rb as a substitute for K+. (-)-Baclofen, a GABAB receptor agonist, produced a concentration-dependent increase in the 86Rb-influx. This effect was stereospecific and blocked by GABAB receptor antagonists like CGP 35 348 (3-aminopropyl-diethoxymethyl-phosphonic acid) and phaclofen. Apart from the GABAB receptors, both adenosine via adenosine1 receptors and 5-hydroxytryptamine (5-HT) via 5-HT1 alpha agonists also increased the 86Rb-influx. These agonists failed to show any additivity between themmore » when they were combined in their maximal concentration. In addition, their effect was antagonized specifically by their respective antagonists without influencing the others. These findings suggest the presence of GABAB, adenosine1 and 5-HT1 alpha receptors in the cultured spinal cord neurons, which exhibit a heterologous regulation of the same K(+)-channel. The effect of these agonists were antagonized by phorbol 12,13-didecanoate, an activator of protein kinase C, and pretreatment with pertussis toxin. This suggests that these agonists by acting on their own receptors converge on the same K(+)-channel through the Gi/Go proteins. In summary, we have developed a biochemical functional assay for studying and characterizing GABAB synaptic pharmacology in vitro, using spinal cord neurons.« less

Production and Its Anti-hyperglycemic Effects of γ-Aminobutyric Acid from the Wild Yeast Strain Pichia silvicola UL6-1 and Sporobolomyces carnicolor 402-JB-1

PubMed Central

Han, Sang-Min

2017-01-01

This study was done to produce γ-aminobutyric acid (GABA) from wild yeast as well as investigate its anti-hyperglycemic effects. Among ten GABA-producing yeast strains, Pichia silvicola UL6-1 and Sporobolomyces carnicolor 402-JB-1 produced high GABA concentration of 134.4 µg/mL and 179.2 µg/mL, respectively. P. silvicola UL6-1 showed a maximum GABA yield of 136.5 µg/mL and 200.8 µg/mL from S. carnicolor 402-JB-1 when they were cultured for 30 hr at 30℃ in yeast extract-peptone-dextrose medium. The cell-free extract from P. silvicola UL6-1 and S. carnicolor 402-JB-1 showed very high anti-hyperglycemic α-glucosidase inhibitory activity of 72.3% and 69.9%, respectively. Additionally, their cell-free extract-containing GABA showed the anti-hyperglycemic effect in streptozotocin-induced diabetic Sprague-Dawley rats. PMID:29138625

Exogenous γ-aminobutyric acid (GABA) affects pollen tube growth via modulating putative Ca2+-permeable membrane channels and is coupled to negative regulation on glutamate decarboxylase

PubMed Central

Yu, Guang-Hui; Zou, Jie; Feng, Jing; Peng, Xiong-Bo; Wu, Ju-You; Wu, Ying-Liang; Palanivelu, Ravishankar; Sun, Meng-Xiang

2014-01-01

γ-Aminobutyric acid (GABA) is implicated in pollen tube growth, but the molecular and cellular mechanisms that it mediates are largely unknown. Here, it is shown that exogenous GABA modulates putative Ca2+-permeable channels on the plasma membranes of tobacco pollen grains and pollen tubes. Whole-cell voltage-clamp experiments and non-invasive micromeasurement technology (NMT) revealed that the influx of Ca2+ increases in pollen tubes in response to exogenous GABA. It is also demonstrated that glutamate decarboxylase (GAD), the rate-limiting enzyme of GABA biosynthesis, is involved in feedback controls of Ca2+-permeable channels to fluctuate intracellular GABA levels and thus modulate pollen tube growth. The findings suggest that GAD activity linked with Ca2+-permeable channels relays an extracellular GABA signal and integrates multiple signal pathways to modulate tobacco pollen tube growth. Thus, the data explain how GABA mediates the communication between the style and the growing pollen tubes. PMID:24799560

Physics of soft hyaluronic acid-collagen type II double network gels

NASA Astrophysics Data System (ADS)

Morozova, Svetlana; Muthukumar, Murugappan

2015-03-01

Many biological hydrogels are made up of multiple interpenetrating, charged components. We study the swelling, elastic diffusion, mechanical, and optical behaviors of 100 mol% ionizable hyaluronic acid (HA) and collagen type II fiber networks. Dilute, 0.05-0.5 wt% hyaluronic acid networks are extremely sensitive to solution salt concentration, but are stable at pH above 2. When swelled in 0.1M NaCl, single-network hyaluronic acid gels follow scaling laws relevant to high salt semidilute solutions; the elastic shear modulus G' and diffusion constant D scale with the volume fraction ϕ as G' ~ϕ 9 / 4 and D ~ϕ 3 / 4 , respectively. With the addition of a collagen fiber network, we find that the hyaluronic acid network swells to suspend the rigid collagen fibers, providing extra strength to the hydrogel. Results on swelling equilibria, elasticity, and collective diffusion on these double network hydrogels will be presented.

Dietary supplementation with glutamine and γ-aminobutyric acid improves growth performance and serum parameters in 22- to 35-day-old broilers exposed to hot environment.

PubMed

Hu, H; Bai, X; Shah, A A; Wen, A Y; Hua, J L; Che, C Y; He, S J; Jiang, J P; Cai, Z H; Dai, S F

2016-04-01

This study was designed using 360 21-day-old chicks to determine the influences of diet supplementation with glutamine (5 g/kg), γ-aminobutyric acid (GABA, 100 mg/kg) or their combinations on performance and serum parameters exposed to cycling high temperatures. From 22 to 35 days, the experimental groups (2 × 2) were subjected to circular heat stress by exposing them to 30-34 °C cycling, while the positive control group was exposed to 23 °C constant. The blood of broilers was collected to detect serum parameters on days 28 and 35. Compared with the positive control group, the cycling high temperature decreased (p < 0.05) the feed consumption, weight gain and serum total protein (TP), glucose, thyroxine (T4), insulin, alkaline phosphatase (ALP), glutamine, GABA and glutamate levels, while increased (p < 0.05) the serum triglyceride (TG), corticosterone (CS), glucagon (GN), creatine kinase (CK), glutamic oxaloacetic transaminase (GOT), nitric oxide synthase (NOS), glutamate pyruvate transaminase (GPT) and lactate dehydrogenase (LDH) levels during 22-35 days. However, dietary glutamine (5 g/kg) increased (p < 0.05) the feed consumption, weight gain and serum levels of glutamine, TP, insulin and ALP, but decreased (p < 0.05) the serum TG, CK, GOT, NOS and GPT levels. Diet supplemented with GABA also increased (p < 0.05) weight gain and the serum levels of TP, T4, ALP, GABA and glutamine. In addition, the significant interactions (p < 0.05) between glutamine and GABA were found in the feed consumption, weight gain and the serum ALP, CK, LDH, GABA, T3 and T4 levels of heat-stressed chickens. This research indicated that dietary glutamine and GABA improved the antistress ability in performance and serum parameters of broilers under hot environment. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

Peripartum neuroactive steroid and γ-aminobutyric acid profiles in women at-risk for postpartum depression

PubMed Central

Deligiannidis, Kristina M.; Kroll-Desrosiers, Aimee R.; Mo, Shunyan; Nguyen, Hien P.; Svenson, Abby; Jaitly, Nina; Hall, Janet E.; Barton, Bruce A.; Rothschild, Anthony J.; Shaffer, Scott A.

2016-01-01

Neuroactive steroids (NAS) are allosteric modulators of the γ-aminobutyric acid (GABA) system. NAS and GABA are implicated in depression. The peripartum period involves physiologic changes in NAS which may be associated with peripartum depression and anxiety. We measured peripartum plasma NAS and GABA in healthy comparison subjects (HCS) and those at-risk for postpartum depression (AR-PPD) due to current mild depressive or anxiety symptoms or a history of depression. We evaluated 56 peripartum medication-free subjects. We measured symptoms with the Hamilton Depression Rating Scale (HAM-D17), Hamilton Anxiety Rating Scale (HAM-A) and Spielberger State-Trait Anxiety Inventory-State (STAI-S). Plasma NAS and GABA were quantified by liquid chromatography-mass spectrometry. We examined the associations between longitudinal changes in NAS, GABA and depressive and anxiety symptoms using generalized estimating equation methods. Peripartum GABA concentration was 1.9 ± 0.7 ng/mL (p=0.004) lower and progesterone and pregnanolone were 15.8 ± 7.5 (p=0.04) and 1.5 ± 0.7 ng/mL (p=0.03) higher in AR-PPD versus HCS, respectively. HAM-D17 was negatively associated with GABA (β=−0.14 ± 0.05, p=0.01) and positively associated with pregnanolone (β=0.16 ± 0.06, p=0.01). STAI-S was positively associated with pregnanolone (β=0.11 ± 0.04, p=0.004), allopregnanolone (β=0.13 ± 0.05, p=0.006) and pregnenolone (β=0.02 ± 0.01, p=0.04). HAM-A was negatively associated with GABA (β=−0.12 ± 0.04, p=0.004) and positively associated with pregnanolone (β=0.11 ± 0.05, p=0.05). Altered peripartum NAS and GABA profiles in AR-PPD women suggest that their interaction may play an important role in the pathophysiology of peripartum depression and anxiety. PMID:27209438

Failure of gamma-aminobutyrate acid-beta agonist baclofen to improve balance, gait, and postural control after vestibular schwannoma resection.

PubMed

De Valck, Claudia F J; Vereeck, Luc; Wuyts, Floris L; Van de Heyning, Paul H

2009-04-01

Incomplete postural control often occurs after vestibular schwannoma (VS) surgery. Customized vestibular rehabilitation in man improves and speeds up this process. Animal experiments have shown an improved and faster vestibular compensation after administration of the gamma-aminobutyrate acid (GABA)-beta agonist baclofen. To examine whether medical treatment with baclofen provides an improvement of the compensation process after VS surgery. A time-series study with historical control. Tertiary referral center. Thirteen patients who underwent VS resection were included and compared with a matched group of patients. In addition to an individualized vestibular rehabilitation protocol, the study group received medical treatment with 30 mg baclofen (a GABA-beta agonist) daily during the first 6 weeks after surgery. Clinical gait and balance tests (Romberg maneuver, standing on foam, tandem Romberg, single-leg stance, Timed Up & Go test, tandem gait, Dynamic Gait Index) and Dizziness Handicap Inventory. Follow-up until 24 weeks after surgery. When examining the postoperative test results, the group treated with baclofen did not perform better when compared with the matched (historical control) group. Repeated-measures analysis of variance revealed no significant group effect, but a significant time effect for almost all balance tests during the acute recovery period was found. An interaction effect between time and intervention was seen concerning single-leg stance and Dizziness Handicap Inventory scores for the acute recovery period. Medical therapy with baclofen did not seem to be beneficial in the process of central vestibular compensation.

Targeted Enhancement of Glutamate-to-γ-Aminobutyrate Conversion in Arabidopsis Seeds Affects Carbon-Nitrogen Balance and Storage Reserves in a Development-Dependent Manner1[W][OA

PubMed Central

Fait, Aaron; Nesi, Adriano Nunes; Angelovici, Ruthie; Lehmann, Martin; Pham, Phuong Anh; Song, Luhua; Haslam, Richard P.; Napier, Johnathan A.; Galili, Gad; Fernie, Alisdair R.

2011-01-01

In seeds, glutamate decarboxylase (GAD) operates at the metabolic nexus between carbon and nitrogen metabolism by catalyzing the unidirectional decarboxylation of glutamate to form γ-aminobutyric acid (GABA). To elucidate the regulatory role of GAD in seed development, we generated Arabidopsis (Arabidopsis thaliana) transgenic plants expressing a truncated GAD from Petunia hybrida missing the carboxyl-terminal regulatory Ca2+-calmodulin-binding domain under the transcriptional regulation of the seed maturation-specific phaseolin promoter. Dry seeds of the transgenic plants accumulated considerable amounts of GABA, and during desiccation the content of several amino acids increased, although not glutamate or proline. Dry transgenic seeds had higher protein content than wild-type seeds but lower amounts of the intermediates of glycolysis, glycerol and malate. The total fatty acid content of the transgenic seeds was 50% lower than in the wild type, while acyl-coenzyme A accumulated in the transgenic seeds. Labeling experiments revealed altered levels of respiration in the transgenic seeds, and fractionation studies indicated reduced incorporation of label in the sugar and lipid fractions extracted from transgenic seeds. Comparative transcript profiling of the dry seeds supported the metabolic data. Cellular processes up-regulated at the transcript level included the tricarboxylic acid cycle, fatty acid elongation, the shikimate pathway, tryptophan metabolism, nitrogen-carbon remobilization, and programmed cell death. Genes involved in the regulation of germination were similarly up-regulated. Taken together, these results indicate that the GAD-mediated conversion of glutamate to GABA during seed development plays an important role in balancing carbon and nitrogen metabolism and in storage reserve accumulation. PMID:21921115

The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides.

PubMed

Barla, Florin; Koyanagi, Takashi; Tokuda, Naoko; Matsui, Hiroshi; Katayama, Takane; Kumagai, Hidehiko; Michihata, Toshihide; Sasaki, Tetsuya; Tsuji, Atsushi; Enomoto, Toshiki

2016-06-01

Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi , narezushi , konkazuke , and ishiru. Various kinds of lactic acid bacteria (LAB) are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA) sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE) inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA) concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v) glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates), Lactobacillus brevis (6 isolates), and Weissella hellenica (2 isolates) had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates), L. buchneri (2 isolates), and W. hellenica (2 isolates) was stronger than that of all whey cultured with soy protein media, and these IC 50 were < 1 mg protein/ml. Three of 10 isolates had high GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.

Phenibut (4-amino-3-phenyl-butyric acid): Availability, prevalence of use, desired effects and acute toxicity.

PubMed

Owen, David R; Wood, David M; Archer, John R H; Dargan, Paul I

2016-09-01

There has been a global increase in the availability and use of novel psychoactive substances (NPS) over the last decade. Phenibut (β-phenyl-γ-aminobutyric acid) is a GABAB agonist that is used as an NPS. Here, we bring together published scientific and grey information sources to further understand the prevalence of use, desired effects and acute toxicity of phenibut. Using European Monitoring Centre for Drugs and Drug Addiction Internet snapshot methodology, we undertook an English language Internet snapshot survey in May 2015 to gather information on the availability and price of phenibut from Internet NPS retailers. To gather information on prevalence of use, desired effects and/or adverse effects, we searched grey literature (online drug discussion forums) and medical literature (PubMed and abstracts from selected International Toxicology conferences). We found 48 unrelated Internet suppliers selling phenibut in amounts ranging from 5 g (US$1.60, £1.01/g) to 1000 kg (US$0.23, £0.14/g). Capsules containing 200-500 mg of phenibut were available in packs of between 6 (US$4.45, £2.80/g) and 360 (US$0.43, £0.27/g). According to the grey literature, phenibut is taken for its anxiolytic and euphoric properties, with tolerance and withdrawal syndromes commonly reported adverse effects. Phenibut is taken orally at an average dose of 2.4 g. Case reports in the medical literature feature users who present to emergency departments heavily sedated or experiencing withdrawal. There have been no reported deaths relating to phenibut use. Phenibut is readily available in the UK from Internet sites selling NPS. Its desired and adverse effects appear similar to other gamma-aminobutyric acid receptor agonists. [Owen DR, Wood DM, Archer JRH, Dargan PI. Phenibut (4-amino-3-phenyl-butyric acid): Availability, prevalence of use, desired effects and acute toxicity. Drug Alcohol Rev 2016;35:591-596]. © 2015 Australasian Professional Society on Alcohol and other Drugs.

Neurochemical correlates of. gamma. -aminobutyrate (GABA) inhibition in cat visual cortex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balcar, V.J.; Dreher, B.

1990-01-01

High affinity binding of ({sup 3}H){gamma}-aminobutyric acid (GABA) to neuronal membranes from different parts of cat visual cortex was tested for sensitivity to GABA{sub A} agonists isoguvacine and THIP, GABA{sub A} antagonist SR95531 and GABA{sub B} agonist baclofen. Some of the GABA{sub A}-binding sites were found to have a very low affinity for THIP, suggesting the presence and, possibly, uneven distribution of non-synaptic GABA{sub A} receptors in cat visual cortex. There were no differences in K{sub m} and V{sub max} values of high affinity uptake of GABA and in the potency of K{sup +}-stimulated release of GABA, between primary andmore » association cortices. Consequently, the present results indicate that despite the anatomical and physiological differences between the primary and association feline visual cortices the neurochemical characteristics of GABAergic inhibition are very similar in the two regions.« less

Targeted metabolomics analysis reveals the association between maternal folic acid supplementation and fatty acids and amino acids profiles in rat pups.

PubMed

Liu, Zhipeng; Liu, Rui; Chou, Jing; Yu, Jiaying; Liu, Xiaowei; Sun, Changhao; Li, Ying; Liu, Liyan

2018-07-15

Maternal diet during pregnancy can influence offspring's health by affecting development and metabolism. This study aimed to analyze the influence of maternal folic acid (FA) supplementation on the metabolism of rat pups using targeted metabolomics. Twenty female rats were randomly assigned to a FA supplementation (FAS group, n = 10) or control group (n = 10), which were fed AIN93G diet with 2 or 10 mg/kg FA, respectively. We then measured amino acids and their derivatives, biogenic amines, and fatty acids in the female rats and their pups by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC/MS-MS) and gas chromatography-mass spectrometry (GC/MS-MS). In maternal rats, the significant changes of three metabolites (proline, γ-aminobutyric acid and esterified octadecatetraenoic acid, P < 0.05) were observed in FAS group. For the rat pups, FAS pups had significantly lower homocysteine and higher FA levels than control pups. The lower levels of amino acids (leucine, isoleucine, serine, proline) were obtained in FAS pups. Furthermore, there were the decreased esterified fatty acids (arachidonic acid, eicosapentaenoic acid, and docosatetraenoic acid) and free fatty acids (oleic acid, linoleic acid, γ-linolenic acid, octadecatetraenoic acid, arachidonic acid, eicosapentaenoic acid and selacholeic acid) in FAS pups. Metabolic changes in the FAS pups were characterized by changes in fatty acids and amino acids. These results suggested that FA supplementation during pregnancy influenced amino acids and fatty acids metabolism in rat pups. This study provides new insights into the regulation of amino acids and fatty acids metabolism during early life. Copyright © 2018 Elsevier B.V. All rights reserved.

Bile alcohols function as the ligands of membrane-type bile acid-activated G protein-coupled receptor

PubMed Central

Iguchi, Yusuke; Yamaguchi, Masafumi; Sato, Hiroyuki; Kihira, Kenji; Nishimaki-Mogami, Tomoko; Une, Mizuho

2010-01-01

TGR5 is a G protein-coupled receptor that is activated by bile acids, resulting in an increase in cAMP levels and the subsequent modulation of energy expenditure in brown adipose tissue and muscle. Therefore, the development of a TGR5-specific agonist could lead to the prevention and treatment of various metabolic disorders related to obesity. In the present study, we evaluated the ability of bile alcohols, which are structurally and physiologically similar to bile acids and are produced as the end products of cholesterol catabolism in evolutionarily primitive vertebrates, to act as TGR5 agonists. In a cell-based reporter assay and a cAMP production assay performed in vitro, most bile alcohols with a side chain containing hydroxyl group(s) were highly efficacious agonists for TGR5 comparable to its most potent ligand in the naturally occurring bile acid, lithocholic acid. However, the abilities of the bile alcohols to activate TGR5 varied with the position and number of the hydroxyl substituent in the side chain. Additionally, the conformation of the steroidal nucleus of bile alcohols is also important for its activity as a TGR5 agonist. Thus, we have provided new insights into the structure-activity relationships of bile alcohols as TGR5 agonists. PMID:20023205

Chemical-exchange-saturation-transfer magnetic resonance imaging to map gamma-aminobutyric acid, glutamate, myoinositol, glycine, and asparagine: Phantom experiments

NASA Astrophysics Data System (ADS)

Oh, Jang-Hoon; Kim, Hyug-Gi; Woo, Dong-Cheol; Jeong, Ha-Kyu; Lee, Soo Yeol; Jahng, Geon-Ho

2017-03-01

The physical and technical development of chemical-exchange-saturation-transfer (CEST) magnetic resonance imaging (MRI) using clinical 3 T MRI was explored with the goal of mapping asparagine (Asn), gamma-aminobutyric acid (GABA), glutamate (Glu), glycine (Gly), and myoinositol (MI), which exist in the brain. Phantoms with nine different conditions at concentrations of 10, 30, and 50 mM and pH values of 5.6, 6.2, and 7.4 were prepared for the five target molecules to evaluate the dependence of the CEST effect in the concentration, the pH, and the amplitude of the applied radiofrequency field B1. CEST images in the offset frequency range of ±6 parts per million (ppm) were acquired using a pulsed radio-frequency saturation scheme with a clinical 3 T MRI system. A voxel-based main magnetic field B0 inhomogeneity correction, where B0 is the center frequency offset at zero ppm, was performed by using the spline interpolation method to fit the full Z-spectrum to estimate the center frequency. A voxel-based CEST asymmetry map was calculated to evaluate amide (-NH), amine (-NH2), and hydroxyl (-OH) groups for the five target molecules. The CEST effect for Glu, GABA, and Gly clearly increased with increasing concentrations. The CEST effect for MI was minimal, with no noticeable differences at different concentrations. The CEST effect for Glu and Gly increased with increasing acidity. The highest CEST asymmetry for GABA was observed at pH 6.2. The CEST effect for Glu, GABA, and Gly increased with increasing B1 amplitude. For all target molecules, the CEST effect for the human 3 T MRI system increased with increasing concentration and B1 amplitude, but varied with pH, depending on the characteristics of the molecules. The CEST effect for MI may be not suitable with clinical MRI systems. These results show that CEST imaging in the brain with the amine protons by using 3 T MRI is possible for several neuronal diseases.

Linking γ-aminobutyric acid A receptor to epidermal growth factor receptor pathways activation in human prostate cancer.

PubMed

Wu, Weijuan; Yang, Qing; Fung, Kar-Ming; Humphreys, Mitchell R; Brame, Lacy S; Cao, Amy; Fang, Yu-Ting; Shih, Pin-Tsen; Kropp, Bradley P; Lin, Hsueh-Kung

2014-03-05

Neuroendocrine (NE) differentiation has been attributed to the progression of castration-resistant prostate cancer (CRPC). Growth factor pathways including the epidermal growth factor receptor (EGFR) signaling have been implicated in the development of NE features and progression to a castration-resistant phenotype. However, upstream molecules that regulate the growth factor pathway remain largely unknown. Using androgen-insensitive bone metastasis PC-3 cells and androgen-sensitive lymph node metastasis LNCaP cells derived from human prostate cancer (PCa) patients, we demonstrated that γ-aminobutyric acid A receptor (GABA(A)R) ligand (GABA) and agonist (isoguvacine) stimulate cell proliferation, enhance EGF family members expression, and activate EGFR and a downstream signaling molecule, Src, in both PC-3 and LNCaP cells. Inclusion of a GABA(A)R antagonist, picrotoxin, or an EGFR tyrosine kinase inhibitor, Gefitinib (ZD1839 or Iressa), blocked isoguvacine and GABA-stimulated cell growth, trans-phospohorylation of EGFR, and tyrosyl phosphorylation of Src in both PCa cell lines. Spatial distributions of GABAAR α₁ and phosphorylated Src (Tyr416) were studied in human prostate tissues by immunohistochemistry. In contrast to extremely low or absence of GABA(A)R α₁-positive immunoreactivity in normal prostate epithelium, elevated GABA(A)R α₁ immunoreactivity was detected in prostate carcinomatous glands. Similarly, immunoreactivity of phospho-Src (Tyr416) was specifically localized and limited to the nucleoli of all invasive prostate carcinoma cells, but negative in normal tissues. Strong GABAAR α₁ immunoreactivity was spatially adjacent to the neoplastic glands where strong phospho-Src (Tyr416)-positive immunoreactivity was demonstrated, but not in adjacent to normal glands. These results suggest that the GABA signaling is linked to the EGFR pathway and may work through autocrine or paracine mechanism to promote CRPC progression. Copyright © 2013 Elsevier

Effects of gamma-aminobutyric acid-modulating drugs on working memory and brain function in patients with schizophrenia.

PubMed

Menzies, Lara; Ooi, Cinly; Kamath, Shri; Suckling, John; McKenna, Peter; Fletcher, Paul; Bullmore, Ed; Stephenson, Caroline

2007-02-01

Cognitive impairment causes morbidity in schizophrenia and could be due to abnormalities of cortical interneurons using the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). To test the predictions that cognitive and brain functional responses to GABA-modulating drugs are correlated and abnormal in schizophrenia. Pharmacological functional magnetic resonance imaging study of 2 groups, each undergoing scanning 3 times, using an N-back working memory task, after placebo, lorazepam, or flumazenil administration. Eleven patients with chronic schizophrenia were recruited from a rehabilitation service, and 11 healthy volunteers matched for age, sex, and premorbid IQ were recruited from the local community. Intervention Participants received 2 mg of oral lorazepam, a 0.9-mg intravenous flumazenil bolus followed by a flumazenil infusion of 0.0102 mg/min, or oral and intravenous placebo. Working memory performance was summarized by the target discrimination index at several levels of difficulty. Increasing (or decreasing) brain functional activation in response to increasing task difficulty was summarized by the positive (or negative) load response. Lorazepam impaired performance and flumazenil enhanced it; these cognitive effects were more salient in schizophrenic patients. Functional magnetic resonance imaging demonstrated positive load response in a frontoparietal system and negative load response in the temporal and posterior cingulate regions; activation of the frontoparietal cortex was positively correlated with deactivation of the temporocingulate cortex. After placebo administration, schizophrenic patients had abnormally attenuated activation of the frontoparietal cortex and deactivation of the temporocingulate cortex; this pattern was mimicked in healthy volunteers and exacerbated in schizophrenic patients by lorazepam. However, in schizophrenic patients, flumazenil enhanced deactivation of the temporocingulate and activation of the anterior cingulate

An open-label tolerability study of BL-1020 antipsychotic: a novel gamma aminobutyric acid ester of perphenazine.

PubMed

Anand, Ravi; Geffen, Yona; Vasile, Daniel; Dan, Irina

2010-01-01

BL-1020, a novel gamma aminobutyric acid (GABA) ester of perphenazine, is a new oral antipsychotic with a strong affinity for dopamine and serotonin receptors. Unlike first- and second-generation antipsychotics, it has agonist activity at GABA(A). This is the first study to examine tolerability and safety of BL-1020 in schizophrenia. This was a phase-II, open-label, multicenter, 6-week study treating patients (n = 36) with chronic schizophrenia. Dosing started at 20 mg/d and increased over 7 days to 40 mg/d. Weekly assessments were conducted. All but 1 patient was titrated to 30 mg/d at day 4; on day 7, 30 were titrated to 40 mg/d. Four patients discontinued the study prematurely. There was no clinically relevant increase in vital signs, sedation, dizziness, or other central nervous system effects or electrocardiogram or laboratory abnormalities and a small increase in weight. Ten patients experienced extrapyramidal symptoms (EPS) requiring treatment with an anticholinergic; 4 patients were unable to reach maximum dose because of EPS. Extrapyramidal Symptom Rating Scale did not indicate clinically significant changes in EPS. The most common adverse event was insomnia (6 patients); other frequent adverse effects (all n = 3) were extrapyramidal disorder, headache, parkinsonism, tremor, and hyperprolactinemia. There was improvement on Positive and Negative Syndrome Scale and Clinical Global Impression of Change with 22 patients showing at least 20% decrease by end point on Positive and Negative Syndrome Scale and 31 patients showing at least minimal improvement on Clinical Global Impression of Change. These data suggest that 20 to 40 mg/d of BL-1020 is associated with clinically relevant improvement of psychosis with no worsening of EPS and support further testing in randomized controlled trials.

Paclitaxel Causes Electrophysiological Changes in the Anterior Cingulate Cortex via Modulation of the γ-Aminobutyric Acid-ergic System.

PubMed

Nashawi, Houda; Masocha, Willias; Edafiogho, Ivan O; Kombian, Samuel B

The aim of this study was to elucidate any electrophysiological changes that may contribute to the development of neuropathic pain during treatment with the anticancer drug paclitaxel, particularly in the γ-aminobutyric acid (GABA) system. One hundred and eight Sprague-Dawley rats were used (untreated control: 43; vehicle-treated: 21, and paclitaxel-treated: 44). Paclitaxel (8 mg/kg) was administered intraperitoneally on 2 alternate days to induce mechanical allodynia. The rats were sacrificed 7 days after treatment to obtain slices of the anterior cingulate cortex (ACC), a brain region involved in the central processing of pain. Field excitatory postsynaptic potentials (fEPSPs) were recorded in layer II/III of ACC slices, and stimulus-response curves were constructed. The observed effects were pharmacologically characterized by bath application of GABA and appropriate drugs to the slices. The paclitaxel-treated rats developed mechanical allodynia (i.e. reduced withdrawal threshold to mechanical stimuli). Slices from paclitaxel-treated rats produced a significantly higher maximal response (Emax) than those from untreated rats (p < 0.001). Bath application of GABA (0.4 µM) reversed this effect and returned the excitability to a level similar to control. Pretreatment of the slices with the GABAB receptor blocker CGP 55845 (50 µM) increased Emax in slices from untreated rats (p < 0.01) but not from paclitaxel-treated rats. In this study, there was a GABA deficit in paclitaxel-treated rats compared to untreated ones. Such a deficit could contribute to the pathophysiology of paclitaxel-induced neuropathic pain (PINP). Thus, the GABAergic system might be a potential therapeutic target for managing PINP. © 2016 S. Karger AG, Basel.

The type III effector HsvG of the gall-forming Pantoea agglomerans mediates expression of the host gene HSVGT.

PubMed

Nissan, Gal; Manulis-Sasson, Shulamit; Chalupowicz, Laura; Teper, Doron; Yeheskel, Adva; Pasmanik-Chor, Metsada; Sessa, Guido; Barash, Isaac

2012-02-01

The type III effector HsvG of the gall-forming Pantoea agglomerans pv. gypsophilae is a DNA-binding protein that is imported to the host nucleus and involved in host specificity. The DNA-binding region of HsvG was delineated to 266 amino acids located within a secondary structure region near the N-terminus of the protein but did not display any homology to canonical DNA-binding motifs. A binding site selection procedure was used to isolate a target gene of HsvG, named HSVGT, in Gypsophila paniculata. HSVGT is a predicted acidic protein of the DnaJ family with 244 amino acids. It harbors characteristic conserved motifs of a eukaryotic transcription factor, including a bipartite nuclear localization signal, zinc finger, and leucine zipper DNA-binding motifs. Quantitative real-time polymerase chain reaction analysis demonstrated that HSVGT transcription is specifically induced in planta within 2 h after inoculation with the wild-type P. agglomerans pv. gypsophilae compared with the hsvG mutant. Induction of HSVGT reached a peak of sixfold at 4 h after inoculation and progressively declined thereafter. Gel-shift assay demonstrated that HsvG binds to the HSVGT promoter, indicating that HSVGT is a direct target of HsvG. Our results support the hypothesis that HsvG functions as a transcription factor in gypsophila.

Altered Markers of Cortical γ-Aminobutyric Acid Neuronal Activity in Schizophrenia

PubMed Central

Kimoto, Sohei; Zaki, Mark M.; Bazmi, H. Holly; Lewis, David A.

2016-01-01

controls: 40.1% lower [P = .003]) and microarray analyses (NARP; individuals with schizophrenia vs controls: 12.2%lower in layer 3 [P = .11] and 14.6%lower in layer 5 pyramidal cells [P = .001]). In schizophrenia specimens, NARP mRNA levels were positively correlated with GAD67 mRNA (r = 0.55; P < .001); the expression of GAD67 mRNA in parvalbumin interneurons is activity dependent. The NARP mRNA levels were also lower than healthy controls in bipolar disorder (−18.2%; F1,60 = 11.39; P = .001) and major depressive disorder (−21.7%; F1,30 = 5.36; P = .03) specimens, especially those from individuals with psychosis. In all 3 diagnostic groups, NARP mRNA levels were positively correlated (all r ≥ 0.53; all P ≤ .02) with somatostatin mRNA, the expression of which is activity dependent. CONCLUSIONS AND RELEVANCE Given the role of NARP in the formation of excitatory inputs to parvalbumin (and perhaps somatostatin) interneurons, our findings suggest that lower NARP mRNA expression contributes to lower excitatory drive onto parvalbumin interneurons in schizophrenia. This reduced excitatory drive may lead to lower synthesis of γ-aminobutyric acid in these interneurons, contributing to a reduced capacity to generate the gamma oscillations required for working memory. PMID:26038830

Two rhodamine 6G derivative compounds: a structural and fluorescence single-crystal study.

PubMed

Di Paolo, Matias; Bossi, Mariano L; Baggio, Ricardo; Suarez, Sebastián A

2016-10-01

The synthesis, characterization, structural analysis and fluorescence properties of two rhodamine 6G derivatives are described, namely a propargylamine derivative, 3',6'-bis(ethylamino)-2',7'-dimethyl-2-(methylcyanide)spiro[isoindole-1,9'-xanthen]-3(2H)-one (I), and a γ-aminobutyric acid (GABA) derivative, 3',6'-bis(ethylamino)-2',7'-dimethyl-3-oxospiro[isoindole-1,9'-xanthen]-2(3H)-yl)butyricacid (II). Both structures are compared with four similar ones from the Cambridge Structural Database (CSD), and the interactions involved in the stabilization are analyzed using the atoms in molecules (AIM) theory. Finally, a single-crystal in-situ reaction study is presented, carried out by fluorescence methods, which enabled the `opening' of the spirolactam ring in the solid phase.

Effects of electroacupuncture on the levels of retinal gamma-aminobutyric acid and its receptors in a guinea pig model of lens-induced myopia.

PubMed

Sha, F; Ye, X; Zhao, W; Xu, C-L; Wang, L; Ding, M-H; Bi, A-L; Wu, J-F; Jiang, W-J; Guo, D-D; Guo, J-G; Bi, H-S

2015-02-26

Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter of the retina and affects myopic development. Electroacupuncture (EA) is widely utilized to treat myopia in clinical settings. However, there are few reports on whether EA affects the level of retinal GABA during myopic development. To study this issue, in the present study, we explored the changes of retinal GABA content and the expression of its receptor subtypes, and the effects of EA stimulation on them in a guinea pig model with lens-induced myopia (LIM). Our results showed that the content of GABA and the expression of GABAA and GABAC receptors of retina were up-regulated during the development of myopia, and this up-regulation was inhibited by applying EA to Hegu (LI4) and Taiyang (EX-HN5) acupoints. Moreover, these effects of EA show a positional specificity. While applying EA at a sham acupoint, no apparent change of myopic retinal GABA and its receptor subtypes was observed. Taken together, our findings suggest that LIM is effective to up-regulate the level of retinal GABA, GABAA and GABAC receptors in guinea pigs and the effect may be inhibited by EA stimulation at LI4 and EX-HN5 acupoints. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Structural Characterisation of FabG from Yersinia pestis, a Key Component of Bacterial Fatty Acid Synthesis.

PubMed

Nanson, Jeffrey D; Forwood, Jade K

2015-01-01

Ketoacyl-acyl carrier protein reductases (FabG) are ubiquitously expressed enzymes that catalyse the reduction of acyl carrier protein (ACP) linked thioesters within the bacterial type II fatty acid synthesis (FASII) pathway. The products of these enzymes, saturated and unsaturated fatty acids, are essential components of the bacterial cell envelope. The FASII reductase enoyl-ACP reductase (FabI) has been the focus of numerous drug discovery efforts, some of which have led to clinical trials, yet few studies have focused on FabG. Like FabI, FabG appears to be essential for survival in many bacteria, similarly indicating the potential of this enzyme as a drug target. FabG enzymes are members of the short-chain alcohol dehydrogenase/reductase (SDR) family, and like other SDRs, exhibit highly conserved secondary and tertiary structures, and contain a number of conserved sequence motifs. Here we describe the crystal structures of FabG from Yersinia pestis (YpFabG), the causative agent of bubonic, pneumonic, and septicaemic plague, and three human pandemics. Y. pestis remains endemic in many parts of North America, South America, Southeast Asia, and Africa, and a threat to human health. YpFabG shares a high degree of structural similarity with bacterial homologues, and the ketoreductase domain of the mammalian fatty acid synthase from both Homo sapiens and Sus scrofa. Structural characterisation of YpFabG, and comparison with other bacterial FabGs and the mammalian fatty acid synthase, provides a strong platform for virtual screening of potential inhibitors, rational drug design, and the development of new antimicrobial agents to combat Y. pestis infections.

Inhibition of l-type amino acid transporter 1 activity as a new therapeutic target for cholangiocarcinoma treatment.

PubMed

Yothaisong, Supak; Dokduang, Hasaya; Anzai, Naohiko; Hayashi, Keitaro; Namwat, Nisana; Yongvanit, Puangrat; Sangkhamanon, Sakkarn; Jutabha, Promsuk; Endou, Hitoshi; Loilome, Watcharin

2017-03-01

Unlike normal cells, cancer cells undergo unlimited growth and multiplication, causing them to require massive amounts of amino acid to support their continuous metabolism. Among the amino acid transporters expressed on the plasma membrane, l-type amino acid transporter-1, a Na + -independent neutral amino acid transporter, is highly expressed in many types of human cancer including cholangiocarcinoma. Our previous study reported that l-type amino acid transporter-1 and its co-functional protein CD98 were highly expressed and implicated in cholangiocarcinoma progression and carcinogenesis. Therefore, this study determined the effect of JPH203, a selective inhibitor of l-type amino acid transporter-1 activity, on cholangiocarcinoma cell inhibition both in vitro and in vivo. JPH203 dramatically suppressed [ 14 C]l-leucine uptake as well as cell growth in cholangiocarcinoma cell lines along with altering the expression of l-type amino acid transporter-1 and CD98 in response to amino acid depletion. We also demonstrated that JPH203 induced both G2/M and G0/G1 cell cycle arrest, as well as reduced the S phase accompanied by altered expression of the proteins in cell cycle progression: cyclin D1, CDK4, and CDK6. There was also cell cycle arrest of the related proteins, P21 and P27, in KKU-055 and KKU-213 cholangiocarcinoma cells. Apoptosis induction, detected by an increase in trypan blue-stained cells along with a cleaved caspase-3/caspase-3 ratio, occurred in JPH203-treated cholangiocarcinoma cells at the highest concentration tested (100 µM). As expected, daily intravenous administration of JPH203 (12.5 and 25 mg/kg) significantly inhibited tumor growth in KKU-213 cholangiocarcinoma cell xenografts in the nude mice model in a dose-dependent manner with no statistically significant change in the animal's body weight and with no differences in the histology and appearance of the internal organs compared with the control group. Our study demonstrates that

The Role of Gut Microbiota in Obesity and Type 2 and Type 1 Diabetes Mellitus: New Insights into "Old" Diseases.

PubMed

Harsch, Igor Alexander; Konturek, Peter Christopher

2018-04-17

The investigation of the human microbiome is the most rapidly expanding field in biomedicine. Early studies were undertaken to better understand the role of microbiota in carbohydrate digestion and utilization. These processes include polysaccharide degradation, glycan transport, glycolysis, and short-chain fatty acid production. Recent research has demonstrated that the intricate axis between gut microbiota and the host metabolism is much more complex. Gut microbiota—depending on their composition—have disease-promoting effects but can also possess protective properties. This review focuses on disorders of metabolic syndrome, with special regard to obesity as a prequel to type 2 diabetes, type 2 diabetes itself, and type 1 diabetes. In all these conditions, differences in the composition of the gut microbiota in comparison to healthy people have been reported. Mechanisms of the interaction between microbiota and host that have been characterized thus far include an increase in energy harvest, modulation of free fatty acids—especially butyrate—of bile acids, lipopolysaccharides, gamma-aminobutyric acid (GABA), an impact on toll-like receptors, the endocannabinoid system and “metabolic endotoxinemia” as well as “metabolic infection.” This review will also address the influence of already established therapies for metabolic syndrome and diabetes on the microbiota and the present state of attempts to alter the gut microbiota as a therapeutic strategy.

Protective propensity of bacoside A and bromelain on renal cholinesterases, γ-Aminobutyric acid and serotonin level of Mus musculus intoxicated with dichlorvos.

PubMed

Agarwal, Sonam; Chaudhary, Bharti; Bist, Renu

2017-01-05

Current study established a protective action of bacoside A and bromelain against the toxic effects of dichlorvos in kidneys of mice. Experimental design included five groups. The first group was control. Mice of groups II, III and IV were administered doses of dichlorvos, bromelain and bacoside A respectively. In group V, mice were treated with both the antioxidants (bacoside A and bromelain) and dichlorvos. After 21 days of exposure of different doses, levels of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), γ-aminobutyric acid (GABA) and serotonin were measured in renal tissues. Dichlorvos significantly reduced the kidney AChE (p < 0.001), BChE (p < 0.01) and GABA level (p < 0.01) compared to control. A simultaneous significant elevation in the serotonin level (p < 0.01) was recorded after dichlorvos exposure. Concomitant exposure of bacoside A and bromelain followed by dichlorvos treatment in group V not only restored, but increased the renal cholinesterases and GABA level. Meanwhile, a significant decline in serotonin level (p < 0.001) was revealed, compared to dichlorvos exposed mice. Bacoside A and bromelain occupy a tremendous antioxidant action in the mice kidneys and a combination of the same ameliorates the renal toxicity induced by dichlorvos. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Quantification of γ-aminobutyric acid (GABA) in 1 H MRS volumes composed heterogeneously of grey and white matter.

PubMed

Mikkelsen, Mark; Singh, Krish D; Brealy, Jennifer A; Linden, David E J; Evans, C John

2016-11-01

The quantification of γ-aminobutyric acid (GABA) concentration using localised MRS suffers from partial volume effects related to differences in the intrinsic concentration of GABA in grey (GM) and white (WM) matter. These differences can be represented as a ratio between intrinsic GABA in GM and WM: r M . Individual differences in GM tissue volume can therefore potentially drive apparent concentration differences. Here, a quantification method that corrects for these effects is formulated and empirically validated. Quantification using tissue water as an internal concentration reference has been described previously. Partial volume effects attributed to r M can be accounted for by incorporating into this established method an additional multiplicative correction factor based on measured or literature values of r M weighted by the proportion of GM and WM within tissue-segmented MRS volumes. Simulations were performed to test the sensitivity of this correction using different assumptions of r M taken from previous studies. The tissue correction method was then validated by applying it to an independent dataset of in vivo GABA measurements using an empirically measured value of r M . It was shown that incorrect assumptions of r M can lead to overcorrection and inflation of GABA concentration measurements quantified in volumes composed predominantly of WM. For the independent dataset, GABA concentration was linearly related to GM tissue volume when only the water signal was corrected for partial volume effects. Performing a full correction that additionally accounts for partial volume effects ascribed to r M successfully removed this dependence. With an appropriate assumption of the ratio of intrinsic GABA concentration in GM and WM, GABA measurements can be corrected for partial volume effects, potentially leading to a reduction in between-participant variance, increased power in statistical tests and better discriminability of true effects. Copyright © 2016 John

Investigation of Cortical Glutamate–Glutamine and γ-Aminobutyric Acid in Obsessive–Compulsive Disorder by Proton Magnetic Resonance Spectroscopy

PubMed Central

Simpson, Helen B; Shungu, Dikoma C; Bender, James; Mao, Xiangling; Xu, Xiaoyan; Slifstein, Mark; Kegeles, Lawrence S

2012-01-01

Glutamatergic abnormalities in corticostriatal brain circuits are thought to underlie obsessive–compulsive disorder (OCD). Whether these abnormalities exist in adults with OCD is not clear. We used proton magnetic resonance spectroscopy (1H MRS) to test our hypothesis that unmedicated adults with OCD have reduced glutamate plus glutamine (Glx) levels in the medial prefrontal cortex (MPFC) compared with healthy controls. Levels of γ-aminobutyric acid (GABA) were also explored. Twenty-four unmedicated adults with OCD and 22 matched healthy control subjects underwent 1H MRS scans at 3.0 T. Resonances of both Glx and GABA were obtained using the standard J-editing technique and assessed as ratios relative to voxel tissue water (W) in the MPFC (the region of interest) and the dorsolateral prefrontal cortex (DLPFC) to explore the regional specificity of any finding. In the MPFC, Glx/W did not differ by diagnostic group (p=0.98) or sex (p=0.57). However, GABA/W was decreased in OCD (2.16±0.46 × 10−3) compared with healthy controls (2.43±0.45 × 10−3, p=0.045); moreover, age of OCD onset was inversely correlated with MPFC GABA/W (r=−0.50, p=0.015). MPFC GABA/W was higher in females than in males. In the DLPFC, there were no main effects of diagnosis or gender on Glx/W or GABA/W. These data indicate that unmedicated adults with OCD do not have Glx abnormalities in a MPFC voxel that includes the pregenual anterior cingulate cortex. However, they may have decreased MPFC GABA levels. How GABA abnormalities might contribute to corticostriatal dysfunction in OCD deserves further study. PMID:22850733

The role of gamma-aminobutyric acid/glycinergic synaptic transmission in mediating bilirubin-induced hyperexcitation in developing auditory neurons.

PubMed

Yin, Xin-Lu; Liang, Min; Shi, Hai-Bo; Wang, Lu-Yang; Li, Chun-Yan; Yin, Shan-Kai

2016-01-05

Hyperbilirubinemia is a common clinical phenomenon observed in human newborns. A high level of bilirubin can result in severe jaundice and bilirubin encephalopathy. However, the cellular mechanisms underlying bilirubin excitotoxicity are unclear. Our previous studies showed the action of gamma-aminobutyric acid (GABA)/glycine switches from excitatory to inhibitory during development in the ventral cochlear nucleus (VCN), one of the most sensitive auditory nuclei to bilirubin toxicity. In the present study, we investigated the roles of GABAA/glycine receptors in the induction of bilirubin hyperexcitation in early developing neurons. Using the patch clamp technique, GABAA/glycine receptor-mediated spontaneous inhibitory synaptic currents (sIPSCs) were recorded from bushy and stellate cells in acute brainstem slices from young mice (postnatal day 2-6). Bilirubin significantly increased the frequency of sIPSCs, and this effect was prevented by pretreatments of slices with either fast or slow Ca(2+) chelators BAPTA-AM and EGTA-AM suggesting that bilirubin can increase the release of GABA/glycine via Ca(2+)-dependent mechanisms. Using cell-attached recording configuration, we found that antagonists of GABAA and glycine receptors strongly attenuated spontaneous spiking firings in P2-6 neurons but produced opposite effect in P15-19 neurons. Furthermore, these antagonists reversed bilirubin-evoked hyperexcitability in P2-6 neurons, indicating that excitatory action of GABA/glycinergic transmission specifically contribute to bilirubin-induced hyperexcitability in the early stage of development. Our results suggest that bilirubin-induced enhancement of presynaptic release GABA/Glycine via Ca(2+)-dependent mechanisms may play a critical role in mediating neuronal hyperexcitation associated with jaundice, implicating potential new strategies for predicting, preventing, and treating bilirubin neurotoxicity. Copyright © 2015. Published by Elsevier Ireland Ltd.

Methanol extract of Nigella sativa seed induces changes in the levels of neurotransmitter amino acids in male rat brain regions.

PubMed

El-Naggar, Tarek; Carretero, María Emilia; Arce, Carmen; Gómez-Serranillos, María Pilar

2017-12-01

Nigella sativa L. (Ranunculaceae) (NS) has been used for medicinal and culinary purposes. Different parts of the plant are used to treat many disorders. This study investigates the effects of NS methanol extract on brain neurotransmitter amino acid levels. We measured the changes in aspartate, glutamate, glycine and γ-aminobutyric acid in five brain regions of male Wistar rats after methanol extract treatment. Animals were injected intraperitoneally with saline solution (controls) or NS methanol extract (equivalent of 2.5 g/kg body weight) and sacrificed 1 h later or after administering 1 daily dose for 8 days. The neurotransmitters were measured in the hypothalamus, cortex, striatum, hippocampus and thalamus by HPLC. Results showed significant changes in amino acids compared to basal values. Glutamate increased significantly (16-36%) in the regions analyzed except the striatum. Aspartate in the hypothalamus (50 and 76%) and glycine in hippocampus (32 and 25%), thalamus (66 and 29%) and striatum (75 and 48%) also increased with the two treatment intervals. γ-Aminobutyric acid significantly increased in the hippocampus (38 and 32%) and thalamus (22 and 40%) but decreased in the cortex and hypothalamus although in striatum only after eight days of treatment (24%). Our results suggest that injected methanol extract modifies amino acid levels in the rat brain regions. These results could be of interest since some neurodegenerative diseases are related to amino acid level imbalances in the central nervous system, suggesting the prospect for therapeutic use of NS against these disorders.

Prefrontal and Striatal Gamma-Aminobutyric Acid Levels and the Effect of Antipsychotic Treatment in First-Episode Psychosis Patients.

PubMed

de la Fuente-Sandoval, Camilo; Reyes-Madrigal, Francisco; Mao, Xiangling; León-Ortiz, Pablo; Rodríguez-Mayoral, Oscar; Jung-Cook, Helgi; Solís-Vivanco, Rodolfo; Graff-Guerrero, Ariel; Shungu, Dikoma C

2018-03-15

Abnormally elevated levels of gamma-aminobutyric acid (GABA) in the medial prefrontal cortex (mPFC) have been reported in antipsychotic-free patients with schizophrenia. Whether such GABA elevations are also present in other brain regions and persist after antipsychotic treatment has not been previously investigated. Twenty-eight antipsychotic-naïve patients with first-episode psychosis (FEP) and 18 healthy control subjects completed the study. Following baseline proton magnetic resonance spectroscopy scans targeting the mPFC and a second region, the dorsal caudate, patients with FEP were treated with oral risperidone for 4 weeks at an initial dose of 1 mg/day that was titrated as necessary based on clinical judgment. After the 4-week treatment period, both groups were brought back to undergo outcome magnetic resonance spectroscopy scans, which were identical to the scans conducted at baseline. At baseline, higher GABA levels were found both in the mPFC and in the dorsal caudate of patients with FEP compared with healthy control subjects. Following 4 weeks of antipsychotic treatment, GABA levels in patients with FEP decreased relative to baseline in the mPFC, but decreased only at the trend level relative to baseline in the dorsal caudate. For either brain region, GABA levels at 4 weeks or posttreatment did not differ between patients with FEP and healthy control subjects. The results of the present study documented elevations of GABA levels both in the mPFC and, for the first time, in the dorsal caudate of antipsychotic-naïve patients with FEP, which normalized in both regions following 4 weeks of antipsychotic treatment. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Immunogenicity of porcine circovirus type 2 nucleic acid vaccine containing CpG motif for mice.

PubMed

Li, Jun; Yu, Jiang; Xu, Shaojian; Shi, Jianli; Xu, Shengnan; Wu, Xiaoyan; Fu, Fang; Peng, Zhe; Zhang, Lingling; Zheng, Shuxuan; Yuan, Xiaoyuan; Cong, Xiaoyan; Sun, Wenbo; Cheng, Kaihui; Du, Yijun; Wu, Jiaqiang; Wang, Jinbao

2016-11-14

This study aimed at reseaching the immune effect of porcine circovirus type 2 (PCV2) DNA vaccine containing CpG motif on mice. A total of 40 6-week-old female BALB/c mice were randomly divided into four groups which were immunized by 18CpG-pVAX1-ORF2, pVAX1-ORF2, pVAX1 and PBS, respectively, and immunized again 2 weeks later. All mice were challenged with 0.2 mL PCV2 cells virulent strain SD (10 6.0 TCID 50 /mL) after 4 weeks. Average daily gain, blood antibody levels, microscopic changes and viremia were detected to estimate the effect of DNA vaccine. The results showed that compared to those of the control mice, groups immunized with pVAX1-ORF2 and 18CpG-pVAX1-ORF2 could induce PCV2-specific antibodies. The PCV2-specific antibodies level of 18 CpG-pVAX1-ORF2 groups was higher significantly than other groups and decreased slowly along with time. There was no distinct pathological damage and viremia occurring in mice that inoculated with CpG motif DNA vaccines. The results demonstrated that the DNA vaccine containing 18 CpG could build up resistibility immunity and reduce immune organ damage on mice.

Monoclonal antibodies and human sera directed to the secreted glycoprotein G of herpes simplex virus type 2 recognize type-specific antigenic determinants.

PubMed

Liljeqvist, Jan-Ake; Trybala, Edward; Hoebeke, Johan; Svennerholm, Bo; Bergström, Tomas

2002-01-01

Glycoprotein G-2 (gG-2) of herpes simplex virus type 2 (HSV-2) is cleaved to a secreted amino-terminal portion (sgG-2) and to a cell-associated carboxy-terminal portion which is further O-glycosylated to constitute the mature gG-2 (mgG-2). In contrast to mgG-2, which is known to elicit a type-specific antibody response in the human host, information on the immunogenic properties of sgG-2 is lacking. Here the sgG-2 protein was purified on a heparin column and used for production of monoclonal antibodies (mAbs). Four anti-sgG-2 mAbs were mapped using a Pepscan technique and identified linear epitopes which localized to the carboxy-terminal part of the protein. One additional anti-sgG-2 mAb, recognizing a non-linear epitope, was reactive to three discrete peptide stretches where the most carboxy-terminally located stretch was constituted by the amino acids (320)RRAL(323). Although sgG-2 is rapidly secreted into the cell-culture medium after infection, the anti-sgG-2 mAbs identified substantial amounts of sgG-2 in the cytoplasm of HSV-2-infected cells. All of the anti-sgG-2 mAbs were HSV-2 specific showing no cross-reactivity to HSV-1 antigen or to HSV-1-infected cells. Similarly, sera from 50 HSV-2 isolation positive patients were all reactive to sgG-2 in an enzyme immunoassay whilst no reactivity was seen in 25 sera from HSV-1 isolation positive patients or in 25 serum samples from HSV-negative patients suggesting that sgG-2 is a novel antigen potentially suitable for type-discriminating serodiagnosis.

Circuit- and Diagnosis-Specific DNA Methylation Changes at γ-Aminobutyric Acid-Related Genes in Postmortem Human Hippocampus in Schizophrenia and Bipolar Disorder.

PubMed

Ruzicka, W Brad; Subburaju, Sivan; Benes, Francine M

2015-06-01

Dysfunction related to γ-aminobutyric acid (GABA)-ergic neurotransmission in the pathophysiology of major psychosis has been well established by the work of multiple groups across several decades, including the widely replicated downregulation of GAD1. Prior gene expression and network analyses within the human hippocampus implicate a broader network of genes, termed the GAD1 regulatory network, in regulation of GAD1 expression. Several genes within this GAD1 regulatory network show diagnosis- and sector-specific expression changes within the circuitry of the hippocampus, influencing abnormal GAD1 expression in schizophrenia and bipolar disorder. To investigate the hypothesis that aberrant DNA methylation contributes to circuit- and diagnosis-specific abnormal expression of GAD1 regulatory network genes in psychotic illness. This epigenetic association study targeting GAD1 regulatory network genes was conducted between July 1, 2012, and June 30, 2014. Postmortem human hippocampus tissue samples were obtained from 8 patients with schizophrenia, 8 patients with bipolar disorder, and 8 healthy control participants matched for age, sex, postmortem interval, and other potential confounds from the Harvard Brain Tissue Resource Center, McLean Hospital, Belmont, Massachusetts. We extracted DNA from laser-microdissected stratum oriens tissue of cornu ammonis 2/3 (CA2/3) and CA1 postmortem human hippocampus, bisulfite modified it, and assessed it with the Infinium HumanMethylation450 BeadChip (Illumina, Inc). The subset of CpG loci associated with GAD1 regulatory network genes was analyzed in R version 3.1.0 software (R Foundation) using the minfi package. Findings were validated using bisulfite pyrosequencing. Methylation levels at 1308 GAD1 regulatory network-associated CpG loci were assessed both as individual sites to identify differentially methylated positions and by sharing information among colocalized probes to identify differentially methylated regions. A total of

Gamma-aminobutyric acid agonists for antipsychotic-induced tardive dyskinesia.

PubMed

Alabed, Samer; Latifeh, Youssef; Mohammad, Husam Aldeen; Bergman, Hanna

2018-04-17

Chronic antipsychotic drug treatment may cause tardive dyskinesia (TD), a long-term movement disorder. Gamma-aminobutyric acid (GABA) agonist drugs, which have intense sedative properties and may exacerbate psychotic symptoms, have been used to treat TD. 1. Primary objectiveThe primary objective was to determine whether using non-benzodiazepine GABA agonist drugs for at least six weeks was clinically effective for the treatment of antipsychotic-induced TD in people with schizophrenia, schizoaffective disorder or other chronic mental illnesses.2. Secondary objectivesThe secondary objectives were as follows.To examine whether any improvement occurred with short periods of intervention (less than six weeks) and, if this did occur, whether this effect was maintained at longer periods of follow-up.To examine whether there was a differential effect between the various compounds.To test the hypothesis that GABA agonist drugs are most effective for a younger age group (less than 40 years old). We searched the Cochrane Schizophrenia Group Trials Register (last searched April 2017), inspected references of all identified studies for further trials, and, when necessary, contacted authors of trials for additional information. We included randomised controlled trials of non-benzodiazepine GABA agonist drugs in people with antipsychotic-induced TD and schizophrenia or other chronic mental illness. Two review authors independently selected and critically appraised studies, extracted and analysed data on an intention-to-treat basis. Where possible and appropriate we calculated risk ratios (RRs) and their 95% confidence intervals (CIs). For continuous data we calculated mean differences (MD). We assumed that people who left early had no improvement. We contacted investigators to obtain missing information. We assessed risk of bias for included studies and created a 'Summary of findings' table using GRADE. We included 11 studies that randomised 343 people. Overall, the risk of bias

Caffeic and chlorogenic acids inhibit key enzymes linked to type 2 diabetes (in vitro): a comparative study.

PubMed

Oboh, Ganiyu; Agunloye, Odunayo M; Adefegha, Stephen A; Akinyemi, Ayodele J; Ademiluyi, Adedayo O

2015-03-01

Chlorogenic acid is a major phenolic compound that forms a substantial part of plant foods and is an ester of caffeic acid and quinic acid. However, the effect of the structures of both chlorogenic and caffeic acids on their antioxidant and antidiabetic potentials have not been fully understood. Thus, this study sought to investigate and compare the interaction of caffeic acid and chlorogenic acid with α-amylase and α-glucosidase (key enzymes linked to type 2 diabetes) activities in vitro. The inhibitory effect of the phenolic acids on α-amylase and α-glucosidase activities was evaluated. Thereafter, their antioxidant activities as typified by their 1,1-diphenyl-2 picrylhydrazyl radical scavenging ability and ferric reducing antioxidant properties were determined. The results revealed that both phenolic acids inhibited α-amylase and α-glucosidase activities in a dose-dependent manner (2-8 μg/mL). However, caffeic acid had a significantly (p<0.05) higher inhibitory effect on α-amylase [IC50 (concentration of sample causing 50% enzyme inhibition)=3.68 μg/mL] and α-glucosidase (IC50=4.98 μg/mL) activities than chlorogenic acid (α-amylase IC50=9.10 μg/mL and α-glucosidase IC50=9.24 μg/mL). Furthermore, both phenolic acids exhibited high antioxidant properties, with caffeic acid showing higher effects. The esterification of caffeic acid with quinic acid, producing chlorogenic acid, reduces their ability to inhibit α-amylase and α-glucosidase activities. Thus, the inhibition of α-amylase and α-glucosidase activities by the phenolic acids could be part of the possible mechanism by which the phenolic acids exert their antidiabetic effects.

Amino acid cycling in the Mississippi River Plume and effects from the passage of Hurricanes Isadore and Lili

NASA Astrophysics Data System (ADS)

Bianchi, Thomas S.; Grace, Bryan L.; Carman, Kevin R.; Maulana, Ivan

2014-08-01

We present data on the effects of Hurricanes Isadore and Lili on the spatial and temporal variations in concentrations of amino acids, and other bulk dissolved and particulate constituents in surface waters of the Mississippi River Plume (MRP) collected during 3 survey cruises (March 2002, October 2002, and April 2004). Abiotic factors (e.g., particle sorption and sediment resuspension) had the largest contribution in describing DAA and PAA dynamics in the MRP. The range of dissolved organic carbon (DOC) (88.61 to 699.90 μM) and particulate organic carbon (POC) (0.08 to 32.72 μM) values was slightly higher than the range observed for a broader region of the Louisiana shelf, but in general agreed with peak values at the mid-salinity range of the plume. The positive and negative correlations between acidic (e.g., aspartic acid and glutamic acid) and basic (e.g., histidine and arginine) DAA and salinity, respectively, in the MRP, were largely controlled by differential partitioning of amino acids with suspended sediments. Concentrations of β-alanine, γ-aminobutyric acid, and δ-aminovaleric acid were significantly higher during October 2002 compared to spring sampling events, due to resuspension of shelf sediments caused by the recent passage of Hurricane Isadore and the approach of Hurricane Lili, as it entered the Gulf of Mexico during our sampling.

Normal postprandial nonesterified fatty acid uptake in muscles despite increased circulating fatty acids in type 2 diabetes.

PubMed

Labbé, Sébastien M; Croteau, Etienne; Grenier-Larouche, Thomas; Frisch, Frédérique; Ouellet, René; Langlois, Réjean; Guérin, Brigitte; Turcotte, Eric E; Carpentier, André C

2011-02-01

Postprandial plasma nonesterified fatty acid (NEFA) appearance is increased in type 2 diabetes. Our objective was to determine whether skeletal muscle uptake of plasma NEFA is abnormal during the postprandial state in type 2 diabetes. Thigh muscle blood flow and oxidative metabolism indexes and NEFA uptake were determined using positron emission tomography coupled with computed tomography (PET/CT) with [(11)C]acetate and 14(R,S)-[(18)F]fluoro-6-thia-heptadecanoic acid ((18)FTHA) in seven healthy control subjects (CON) and seven subjects with type 2 diabetes during continuous oral intake of a liquid meal to achieve steady postprandial NEFA levels with insulin infusion to maintain similar plasma glucose levels in both groups. In the postprandial state, plasma NEFA level was higher in type 2 diabetic subjects versus CON (P < 0.01), whereas plasma glucose was at the same level in both groups. Muscle NEFA fractional extraction and blood flow index levels were 56% (P < 0.05) and 24% (P = 0.27) lower in type 2 diabetes, respectively. However, muscle NEFA uptake was similar to that of CON (quadriceps femoris [QF] 1.47 ± 0.23 vs. 1.37 ± 0.24 nmol·g(-1)·min(-1), P = 0.77; biceps femoris [BF] 1.54 ± 0.26 vs. 1.46 ± 0.28 nmol·g(-1)·min(-1), P = 0.85). Muscle oxidative metabolism was similar in both groups. Muscle NEFA fractional extraction and blood flow index were strongly and positively correlated (r = 0.79, P < 0.005). Postprandial muscle NEFA uptake is normal despite elevated systemic NEFA levels and acute normalization of plasma glucose in type 2 diabetes. Lower postprandial muscle blood flow with resulting reduction in muscle NEFA fractional extraction may explain this phenomenon.

Delta Subunit-Containing Gamma-Aminobutyric Acid A Receptor Disinhibits Lateral Amygdala and Facilitates Fear Expression in Mice.

PubMed

Liu, Zhi-Peng; He, Qing-Hai; Pan, Han-Qing; Xu, Xiao-Bin; Chen, Wen-Bing; He, Ye; Zhou, Jin; Zhang, Wen-Hua; Zhang, Jun-Yu; Ying, Xiao-Ping; Han, Ren-Wen; Li, Bao-Ming; Gao, Tian-Ming; Pan, Bing-Xing

2017-06-15

Maintaining gamma-aminobutyric acidergic (GABAergic) inhibition in the amygdala within a physiological range is critical for the appropriate expression of emotions such as fear and anxiety. The synaptic GABA type A receptor (GABA A R) is generally known to mediate the primary component of amygdala inhibition and prevent inappropriate expression of fear. However, little is known about the contribution of the extrasynaptic GABA A R to amygdala inhibition and fear. By using mice expressing green fluorescent protein in interneurons (INs) and lacking the δ subunit-containing GABA A R (GABA A (δ)R), which is exclusively situated in the extrasynaptic membrane, we systematically investigated the role of GABA A (δ)R in regulating inhibition in the lateral amygdala (LA) and fear learning using the combined approaches of immunohistochemistry, electrophysiology, and behavior. In sharp contrast to the established role of synaptic GABA A R in mediating LA inhibition, we found that either pharmacological or physiological recruitment of GABA A (δ)R resulted in the weakening of GABAergic transmission onto projection neurons in LA while leaving the glutamatergic transmission unaltered, suggesting disinhibition by GABA A (δ)R. The disinhibition arose from IN-specific expression of GABA A (δ)R with its activation decreasing the input resistance of local INs and suppressing their activation. Genetic deletion of GABA A (δ)R attenuated its role in suppressing LA INs and disinhibiting LA. Importantly, the GABA A (δ)R facilitated long-term potentiation in sensory afferents to LA and permitted the expression of learned fear. Our findings suggest that GABA A (δ)R serves as a brake rather than a mediator of GABAergic inhibition in LA. The disinhibition by GABA A (δ)R may help to prevent excessive suppression of amygdala activity and thus ensure the expression of emotion. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Modulation of Pain Transmission by G Protein-Coupled Receptors

PubMed Central

Pan, Hui-Lin; Wu, Zi-Zhen; Zhou, Hong-Yi; Chen, Shao-Rui; Zhang, Hong-Mei; Li, De-Pei

2010-01-01

The heterotrimeric G protein-coupled receptors (GPCRs) represent the largest and most diverse family of cell surface receptors and proteins. GPCRs are widely distributed in the peripheral and central nervous systems and are one of the most important therapeutic targets in pain medicine. GPCRs are present on the plasma membrane of neurons and their terminals along the nociceptive pathways and are closely associated with the modulation of pain transmission. GPCRs that can produce analgesia upon activation include opioid, cannabinoid, α2-adrenergic, muscarinic acetylcholine, γ-aminobutyric acidB (GABAB), group II and III metabotropic glutamate, and somatostatin receptors. Recent studies have led to a better understanding of the role of these GPCRs in the regulation of pain transmission. Here, we review the current knowledge about the cellular and molecular mechanisms that underlie the analgesic actions of GPCR agonists, with a focus on their effects on ion channels expressed on nociceptive sensory neurons and on synaptic transmission at the spinal cord level. PMID:17959251

Engineering wild-type robust Pediococcus acidilactici strain for high titer L- and D-lactic acid production from corn stover feedstock.

PubMed

Yi, Xia; Zhang, Peng; Sun, Jiaoe; Tu, Yi; Gao, Qiuqiang; Zhang, Jian; Bao, Jie

2016-01-10

Pediococcus acidilactici TY112 producing L-lactic acid and P. acidilactici ZP26 producing D-lactic acid, were engineered from the wild-type P. acidilactici DQ2 by ldhD or ldh gene disruption, and the robustness of the wild-type strain to the inhibitors derived from lignocellulose pretreatment was maintained well. In simultaneous saccharification and fermentation (SSF), 77.66 g L(-1) of L-lactic acid and 76.76 g L(-1) of D-lactic acid were obtained at 25% (w/w) solids content of dry dilute acid pretreated and biodetoxified corn stover feedstock. L- and D-Lactic acid yield and productivity were highly dependent on the inhibitor removal extent due to the significant down-regulation on the expressions of ldh and ldhD encoding lactate dehydrogenase by inhibitor, especially syringaldehyde and vanillin at the low concentrations. This study provided a prototype of industrial process for high titer L- and D-lactic acid production from lignocellulose feedstock. Copyright © 2015 Elsevier B.V. All rights reserved.

Induction of Direct or Priming Resistance against Botrytis cinerea in Strawberries by β-Aminobutyric Acid and Their Effects on Sucrose Metabolism.

PubMed

Wang, Kaituo; Liao, Yunxia; Xiong, Qi; Kan, Jianquan; Cao, Shifeng; Zheng, Yonghua

2016-07-27

The specific forms of disease resistance induced by β-aminobutyric acid (BABA) and their impacts on sucrose metabolism of postharvest strawberries were determined in the present research. Treatment with 10-500 mmol L(-1) BABA inhibited the Botrytis cinerea infection, possibly directly by suppressing the fungus growth and indirectly by triggering disease resistance. Moreover, BABA-induced resistance against B. cinerea infection in strawberries was associated with either one of two mechanisms, depending upon the concentration used: BABA at concentrations higher than 100 mmol L(-1) directly induced the defense response, including a H2O2 burst, modulation of the expression of PR genes, including FaPR1, FaChi3, Faβglu, and FaPAL, and increased activities of chitinase, β-1,3-glucanase, and PAL, whereas BABA at 10 mmol L(-1) activated a priming response because the BABA-treated fruits exhibited an increased capacity to express molecular defense only when the fruits were inoculated with B. cinerea. Activation of the priming defense appeared almost as effective against B. cinerea as inducing direct defense. However, the primed strawberries maintained higher activities of SS synthesis and SPS and SPP enzymes) and lower level of SS cleavage during the incubation; these activities contributed to higher sucrose, fructose, and glucose contents, sweetness index, and sensory scores compared to fruits exhibiting the direct defense. Thus, it is plausible that the priming defense, which can be activated by BABA at relatively low concentrations, represents an optimal strategy for combining the advantages of enhanced disease protection and soluble sugar accumulation.

Effects of yoga on the autonomic nervous system, gamma-aminobutyric-acid, and allostasis in epilepsy, depression, and post-traumatic stress disorder.

PubMed

Streeter, C C; Gerbarg, P L; Saper, R B; Ciraulo, D A; Brown, R P

2012-05-01

A theory is proposed to explain the benefits of yoga practices in diverse, frequently comorbid medical conditions based on the concept that yoga practices reduce allostatic load in stress response systems such that optimal homeostasis is restored. It is hypothesized that stress induces (1) imbalance of the autonomic nervous system (ANS) with decreased parasympathetic nervous system (PNS) and increased sympathetic nervous system (SNS) activity, (2) underactivity of the gamma amino-butyric acid (GABA) system, the primary inhibitory neurotransmitter system, and (3) increased allostatic load. It is further hypothesized that yoga-based practices (4) correct underactivity of the PNS and GABA systems in part through stimulation of the vagus nerves, the main peripheral pathway of the PNS, and (5) reduce allostatic load. Depression, epilepsy, post traumatic stress disorder (PTSD), and chronic pain exemplify medical conditions that are exacerbated by stress, have low heart rate variability (HRV) and low GABAergic activity, respond to pharmacologic agents that increase activity of the GABA system, and show symptom improvement in response to yoga-based interventions. The observation that treatment resistant cases of epilepsy and depression respond to vagal nerve stimulation corroborates the need to correct PNS underactivity as part of a successful treatment plan in some cases. According to the proposed theory, the decreased PNS and GABAergic activity that underlies stress-related disorders can be corrected by yoga practices resulting in amelioration of disease symptoms. This has far-reaching implications for the integration of yoga-based practices in the treatment of a broad array of disorders exacerbated by stress. Copyright © 2012 Elsevier Ltd. All rights reserved.

Relationship of executive functioning deficits to N-acetyl aspartate (NAA) and gamma-aminobutyric acid (GABA) in youth with bipolar disorder.

PubMed

Huber, Rebekah S; Kondo, Douglas G; Shi, Xian-Feng; Prescot, Andrew P; Clark, Elaine; Renshaw, Perry F; Yurgelun-Todd, Deborah A

2018-01-01

Although cognitive deficits in bipolar disorder (BD) have been repeatedly observed, our understanding of these impairments at a mechanistic level remains limited. Few studies that investigated cognitive impairments in bipolar illness have examined the association with brain biochemistry. This pilot study utilized proton magnetic resonance spectroscopy ( 1 H-MRS) to evaluate the relationship between neurocognitive performance and brain metabolites in youth with BD. Thirty participants, twenty depressed BD participants and ten healthy comparison participants, ages 13-21, completed mood and executive function measures. 1 H-MRS data were also acquired from the anterior cingulate cortex (ACC) using two-dimensional (2D) J-resolved 1 H-MRS sequence. Proton metabolites including N-acetyl aspartate (NAA) and gamma-aminobutyric acid (GABA) were quantified for both groups. Participants with BD performed significantly lower on executive functioning measures than comparison participants. There were significant positive correlations between Wisconsin Card Sorting Test (WCST) performance and NAA (p < .001) and GABA (p < .01) in the ACC in bipolar youth, such that as WCST performance increased, both NAA and GABA levels increased. Small sample size and lack of control for medications. These findings build on previous observations of biochemical alterations associated with BD and indicate that executive functioning deficits in bipolar youth are correlated with NAA and GABA. These results suggest that cognitive deficits occur early in the course of illness and may reflect risk factors associated with altered neurochemistry. Further investigation of the relationship between brain metabolites and cognition in BD may lead to important information for developing novel, targeted interventions. Copyright © 2017 Elsevier B.V. All rights reserved.

Pretreatment of liver grafts in vivo by γ-aminobutyric acid receptor regulation reduces cold ischemia/warm reperfusion injury in rat

PubMed Central

Hori, Tomohide; Gardner, Lindsay B.; Hata, Toshiyuki; Chen, Feng; Baine, Ann-Marie T.; Uemoto, Shinji; Nguyen, Justin H.

2014-01-01

Summary Background: Gamma-aminobutyric acid (GABA) is found throughout the body. The regulation of GABA receptor (GABAR) reduces oxidative stress (OS). Ischemia/reperfusion injury after orthotopic liver transplantation (OLT) causes OS-induced graft damage. The effects of GABAR regulation in donors in vivo were investigated. Material/Methods: Donor rats received saline, a GABAR agonist or GABAR antagonist 4 h before surgery. Recipient rats were divided into four groups according to the donor treatments: laparotomy, OLT with saline, OLT with GABAR agonist and OLT with GABAR antagonist. Histopathological, biochemical and immunohistological examinations were performed at 6, 12 and 24 h after OLT. Protein assays were performed at 6 h after OLT. The 4-hydroxynonenal (4-HNE), ataxia-telangiectasia mutated kinase (ATM), phosphorylated histone H2AX (γH2AX), phosphatidylinositol-3 kinase (PI3K), Akt and superoxide dismutase (SOD) were assessed by western blot analysis. Results: In the univariate analysis, histopathological and biochemical profiles verified that the GABAR agonist reduced graft damage. Immunohistology revealed that the GABAR agonist prevented the induction of apoptosis. Measurement of 4-4-HNE levels confirmed OS-induced damage after OLT, and the GABAR agonist improved this damage. In the γH2AX, PI3K, Akt and antioxidant enzymes (SODs), ATM and H2AX were greatly increased after OLT, and were reduced by the GABAR agonist. In the multivariate analyses between multiple groups, histopathological assessment, aspartate aminotransferase level, immunohistological examinations for apoptotic induction and γH2AX showed statistical differences. Conclusions: A specific agonist demonstrated regulation of GABAR in vivo in the liver. This activation in vivo reduced OS after OLT via the ATM/H2AX pathway. PMID:23792534

In vivo gamma-aminobutyric acid and glutamate levels in people with first-episode schizophrenia: A proton magnetic resonance spectroscopy study.

PubMed

Chiu, P W; Lui, Simon S Y; Hung, Karen S Y; Chan, Raymond C K; Chan, Queenie; Sham, P C; Cheung, Eric F C; Mak, Henry K F

2018-03-01

Gamma-aminobutyric acid (GABA) dysfunction and its consequent imbalance are implicated in the pathophysiology of schizophrenia. Reduced GABA production would lead to a disinhibition of glutamatergic neurons and subsequently cause a disruption of the modulation between GABAergic interneurons and glutamatergic neurons. In this study, levels of GABA, Glx (summation of glutamate and glutamine), and other metabolites in the anterior cingulate cortex were measured and compared between first-episode schizophrenia subjects and healthy controls (HC). Diagnostic potential of GABA and Glx as upstream biomarkers for schizophrenia was explored. Nineteen first-episode schizophrenia subjects and fourteen HC participated in this study. Severity of clinical symptoms of patients was measured with Positive and Negative Syndrome Scale (PANSS). Metabolites were measured using proton magnetic resonance spectroscopy, and quantified using internal water as reference. First-episode schizophrenia subjects revealed reduced GABA and myo-inositol (mI), and increased Glx and choline (Cho), compared to HC. No significant correlation was found between metabolite levels and PANSS scores. Receiver operator characteristics analyses showed Glx had higher sensitivity and specificity (84.2%, 92.9%) compared to GABA (73.7%, 64.3%) for differentiating schizophrenia patients from HC. Combined model of both GABA and Glx revealed the best sensitivity and specificity (89.5%, 100%). This study simultaneously showed reduction in GABA and elevation in Glx in first-episode schizophrenia subjects, and this might provide insights on explaining the disruption of modulation between GABAergic interneurons and glutamatergic neurons. Elevated Cho might indicate increased membrane turnover; whereas reduced mI might reflect dysfunction of the signal transduction pathway. In vivo Glx and GABA revealed their diagnostic potential for schizophrenia. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of dietary γ-aminobutyric acid on the nerve growth factor and the choline acetyltransferase in the cerebral cortex and hippocampus of ovariectomized female rats.

PubMed

Tujioka, Kazuyo; Thanapreedawat, Panicha; Yamada, Takashi; Yokogoshi, Hidehiko; Horie, Kenji; Kim, Mujo; Tsutsui, Kazumi; Hayase, Kazutoshi

2014-01-01

The brain protein synthesis and the plasma concentration of growth hormone (GH) is sensitive to the dietary γ-aminobutyric acid (GABA) in ovariectomized female rats; however, the role of dietary GABA on biomarkers including nerve growth factor (NGF) and choline acetyltransferase for the function of cholinergic neurons remains unknown in ovariectomized female rats. The purpose of this study was to determine whether the dietary GABA affects the concentration and mRNA level of NGF, and the activity of choline acetyltransferase in the brains of ovariectomized female rats. Experiments were done on two groups of 24-wk-old ovariectomized female rats given 0 or 0.5% GABA added to a 20% casein diet. The concentrations of NGF and activities of choline acetyltransferase in the cerebral cortex and hippocampus, and mRNA level of NGF in the hippocampus increased significantly with the 20% casein+0.5% GABA compared with the 20% casein diet alone. In the hippocampus, the mRNA level of NGF significantly correlated with the NGF concentration (r=0.714, p<0.01). These results suggest that the administration of GABA to ovariectomized female rats is likely to control the mRNA level and concentration of NGF and cause an increase in the activity of choline acetyltransferase in the brains.

Ribosomal binding site sequences and promoters for expressing glutamate decarboxylase and producing γ-aminobutyrate in Corynebacterium glutamicum.

PubMed

Shi, Feng; Luan, Mingyue; Li, Yongfu

2018-04-18

Glutamate decarboxylase (GAD) converts L-glutamate (Glu) into γ-aminobutyric acid (GABA). Corynebacterium glutamicum that expresses exogenous GAD gene, gadB2 or gadB1, can synthesize GABA from its own produced Glu. To enhance GABA production in C. glutamicum, ribosomal binding site (RBS) sequence and promoter were searched and optimized for increasing the expression efficiency of gadB2. R4 exhibited the highest strength among RBS sequences tested, with 6 nt the optimal aligned spacing (AS) between RBS and start codon. This combination of RBS sequence and AS contributed to gadB2 expression, increased GAD activity by 156% and GABA production by 82% compared to normal strong RBS and AS combination. Then, a series of native promoters were selected for transcribing gadB2 under optimal RBS and AS combination. P dnaK , P dtsR , P odhI and P clgR expressed gadB2 and produced GABA as effectively as widely applied P tuf and P cspB promoters and more effectively than P sod promoter. However, each native promoter did not work as well as the synthetic strong promoter P tacM , which produced 20.2 ± 0.3 g/L GABA. Even with prolonged length and bicistronic architecture, the strength of P dnaK did not enhance. Finally, gadB2 and mutant gadB1 were co-expressed under the optimal promoter and RBS combination, thus converted Glu into GABA completely and improved GABA production to more than 25 g/L. This study provides useful promoters and RBS sequences for gene expression in C. glutamicum.

Heterotrimeric G proteins-mediated resistance to necrotrophic pathogens includes mechanisms independent of salicylic acid-, jasmonic acid/ethylene- and abscisic acid-mediated defense signaling.

PubMed

Trusov, Yuri; Sewelam, Nasser; Rookes, James Edward; Kunkel, Matt; Nowak, Ekaterina; Schenk, Peer Martin; Botella, José Ramón

2009-04-01

Heterotrimeric G proteins are involved in the defense response against necrotrophic fungi in Arabidopsis. In order to elucidate the resistance mechanisms involving heterotrimeric G proteins, we analyzed the effects of the Gβ (subunit deficiency in the mutant agb1-2 on pathogenesis-related gene expression, as well as the genetic interaction between agb1-2 and a number of mutants of established defense pathways. Gβ-mediated signaling suppresses the induction of salicylic acid (SA)-, jasmonic acid (JA)-, ethylene (ET)- and abscisic acid (ABA)-dependent genes during the initial phase of the infection with Fusarium oxysporum (up to 48 h after inoculation). However, at a later phase it enhances JA/ET-dependent genes such as PDF1.2 and PR4. Quantification of the Fusarium wilt symptoms revealed that Gβ- and SA-deficient mutants were more susceptible than wild-type plants, whereas JA- and ET-insensitive and ABA-deficient mutants demonstrated various levels of resistance. Analysis of the double mutants showed that the Gβ-mediated resistance to F. oxysporum and Alternaria brassicicola was mostly independent of all of the previously mentioned pathways. However, the progressive decay of agb1-2 mutants was compensated by coi1-21 and jin1-9 mutations, suggesting that at this stage of F. oxysporum infection Gβ acts upstream of COI1 and ATMYC2 in JA signaling. © 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.

Effect of Meat Type, Animal Fatty Acid Composition, and Isothermal Temperature on the Viscoelastic Properties of Meat Batters.

PubMed

Glorieux, Seline; Steen, Liselot; De Brabanter, Jos; Foubert, Imogen; Fraeye, Ilse

2018-05-22

The aim of this research was to simultaneously study the effect of meat type (chicken breast and leg meat), animal fatty acid composition (selected pork backfats having a low and high degree of saturation, respectively), and isothermal temperature (50, 60, 70, and 80 °C) on the viscoelastic properties of meat batters during and after application of different time-temperature profiles. Gelation of meat proteins contributed most to the viscoelastic properties of meat batters during heating, whereas crystallization of the lipids especially contributed to the viscoelastic properties during the cooling phase. Although the meat type had little effect on the final viscoelastic properties of the meat product, the fatty acid composition had a clear impact on the melting peak area (and therefore solid fat content) of lard, and subsequently on the final viscoelastic properties of meat batters prepared with different types of fats, with higher G' (elastic modulus) values for the most saturated animal fat. The crystallization of the fat clearly transcended the effect of the meat type with regard to G' at the end of the process. With increasing (isothermal) temperature, G' of meat batters increased. Therefore, it could be concluded that the structural properties of heated meat batters mainly depend on the heating temperature and the fatty acid composition, rather than the meat type. Quality characteristics of cooked sausages depend on multiple factors such as the meat and fat type, non-meat ingredients and processing conditions. From this study it could be concluded that the structural properties of cooked sausage batters mainly depend on the heating temperature and the fatty acid composition, rather than the meat type. Because the fatty acid composition of different animal fats differs widely, these results may be a concern for all manufactures of cooked sausages products with regard to the product structure and final texture, keeping in mind that rendered fat was used in this

Modification on ursodeoxycholic acid (UDCA) scaffold. discovery of bile acid derivatives as selective agonists of cell-surface G-protein coupled bile acid receptor 1 (GP-BAR1).

PubMed

Sepe, Valentina; Renga, Barbara; Festa, Carmen; D'Amore, Claudio; Masullo, Dario; Cipriani, Sabrina; Di Leva, Francesco Saverio; Monti, Maria Chiara; Novellino, Ettore; Limongelli, Vittorio; Zampella, Angela; Fiorucci, Stefano

2014-09-25

Bile acids are signaling molecules interacting with the nuclear receptor FXR and the G-protein coupled receptor 1 (GP-BAR1/TGR5). GP-BAR1 is a promising pharmacological target for the treatment of steatohepatitis, type 2 diabetes, and obesity. Endogenous bile acids and currently available semisynthetic bile acids are poorly selective toward GP-BAR1 and FXR. Thus, in the present study we have investigated around the structure of UDCA, a clinically used bile acid devoid of FXR agonist activity, to develop a large family of side chain modified 3α,7β-dihydroxyl cholanoids that selectively activate GP-BAR1. In vivo and in vitro pharmacological evaluation demonstrated that administration of compound 16 selectively increases the expression of pro-glucagon 1, a GP-BAR1 target, in the small intestine, while it had no effect on FXR target genes in the liver. Further, compound 16 results in a significant reshaping of bile acid pool in a rodent model of cholestasis. These data demonstrate that UDCA is a useful scaffold to generate novel and selective steroidal ligands for GP-BAR1.

Effect of Oral Sebacic Acid on Postprandial Glycemia, Insulinemia, and Glucose Rate of Appearance in Type 2 Diabetes

PubMed Central

Iaconelli, Amerigo; Gastaldelli, Amalia; Chiellini, Chiara; Gniuli, Donatella; Favuzzi, Angela; Binnert, Christophe; Macé, Katherine; Mingrone, Geltrude

2010-01-01

OBJECTIVE Dicarboxylic acids are natural products with the potential of being an alternate dietary source of energy. We aimed to evaluate the effect of sebacic acid (a 10-carbon dicarboxylic acid; C10) ingestion on postprandial glycemia and glucose rate of appearance (Ra) in healthy and type 2 diabetic subjects. Furthermore, the effect of C10 on insulin-mediated glucose uptake and on GLUT4 expression was assessed in L6 muscle cells in vitro. RESEARCH DESIGN AND METHODS Subjects ingested a mixed meal (50% carbohydrates, 15% proteins, and 35% lipids) containing 0 g (control) or 10 g C10 in addition to the meal or 23 g C10 as a substitute of fats. RESULTS In type 2 diabetic subjects, the incremental glucose area under the curve (AUC) decreased by 42% (P < 0.05) and 70% (P < 0.05) in the 10 g C10 and 23 g C10 groups, respectively. At the largest amounts used, C10 reduced the glucose AUC in healthy volunteers also. When fats were substituted with 23 g C10, AUC of Ra was significantly reduced on the order of 18% (P < 0.05) in both healthy and diabetic subjects. The insulin-dependent glucose uptake by L6 cells was increased in the presence of C10 (38.7 ± 10.3 vs. 11.4 ± 5.4%; P = 0.026). This increase was associated with a 1.7-fold raise of GLUT4. CONCLUSIONS Sebacic acid significantly reduced hyperglycemia after a meal in type 2 diabetic subjects. This beneficial effect was associated with a reduction in glucose Ra, probably due to lowered hepatic glucose output and increased peripheral glucose disposal. PMID:20724647

Altered γ-aminobutyric acid neurotransmission in major depressive disorder: a critical review of the supporting evidence and the influence of serotonergic antidepressants

PubMed Central

Pehrson, Alan L; Sanchez, Connie

2015-01-01

Evidence suggesting that central nervous system γ-aminobutyric acid (GABA) concentrations are reduced in patients with major depressive disorder (MDD) has been present since at least 1980, and this idea has recently gained support from more recent magnetic resonance spectroscopy data. These observations have led to the assumption that MDD’s underlying etiology is tied to an overall reduction in GABA-mediated inhibitory neurotransmission. In this paper, we review the mechanisms that govern GABA and glutamate concentrations in the brain, and provide a comprehensive and critical evaluation of the clinical data supporting reduced GABA neurotransmission in MDD. This review includes an evaluation of magnetic resonance spectroscopy data, as well as data on the expression and function of the GABA-synthesizing enzyme glutamic acid decarboxylase, GABA neuron-specific cell markers, such as parvalbumin, calretinin and calbindin, and the GABAA and GABAB receptors in clinical MDD populations. We explore a potential role for glial pathology in MDD-related reductions in GABA concentrations, and evidence of a connection between neurosteroids, GABA neurotransmission, and hormone-related mood disorders. Additionally, we investigate the effects of GABAergic pharmacological agents on mood, and demonstrate that these compounds have complex effects that do not universally support the idea that reduced GABA neurotransmission is at the root of MDD. Finally, we discuss the connections between serotonergic and GABAergic neurotransmission, and show that two serotonin-focused antidepressants – the selective serotonin-reuptake inhibitor fluoxetine and the multimodal antidepressant vortioxetine – modulate GABA neurotransmission in opposing ways, despite both being effective MDD treatments. Altogether, this review demonstrates that there are large gaps in our understanding of the relationship between GABA physiology and MDD, which must be remedied with more data from well

Perinatal intermittent hypoxia alters γ-aminobutyric acid: a receptor levels in rat cerebellum.

PubMed

Pae, Eung-Kwon; Yoon, Audrey J; Ahuja, Bhoomika; Lau, Gary W; Nguyen, Daniel D; Kim, Yong; Harper, Ronald M

2011-12-01

Perinatal hypoxia commonly causes brain injury in infants, but the time course and mechanisms underlying the preferential male injury are unclear. Intermittent hypoxia disturbs cerebellar γ-aminobutyric (GABA)-A receptor profiles during the perinatal period, possibly responding to transient excitatory processes associated with GABA(A) receptors. We examined whether hypoxic insults were particularly damaging to the male rodent cerebellum during a specific developmental time window. We evaluated cerebellar injury and GABA(A) receptor profiles following 5-h intermittent hypoxia (IH: 20.8% and 10.3% ambient oxygen, switched every 240s) or room-air control in groups of male and female rat pups on postnatal d 1-2, wk 1, or wk 3. The cerebella were harvested and compared between groups. The mRNA levels of GABA(A) receptors α6, normalized to a house-keeping gene GAPDH, and assessed using real-time reverse-transcriptase PCR assays were up-regulated by IH at wk 1, more extensively in male rats, with sex influencing the regulatory time-course. In contrast, GABA(A) α6 receptor protein expression levels, assessed using Western blot assays, reached a nadir at wk 1 in both male and female rats, possibly indicating involvement of a post-transcriptional mechanism. The extent of cerebellar damage and level of apoptosis, assessed by DNA fragmentation, were greatest in the wk 3 IH-exposed group. The findings suggest partial protection for female rats against early hypoxic insult in the cerebellum, and that down-regulation of GABA(A) receptors, rather than direct neural injury assessed by DNA fragmentation may modify cerebellar function, with potential later motor and other deficits. Copyright © 2011 ISDN. Published by Elsevier Ltd. All rights reserved.

The ethyl acetate extract of Phellinus linteus grown on germinated brown rice induces G0/G1 cell cycle arrest and apoptosis in human colon carcinoma HT29 cells.

PubMed

Park, Hye-Jin; Choi, Se Young; Hong, Se Mi; Hwang, Sung Gu; Park, Dong Ki

2010-07-01

It is well known that Phellinus linteus has a variety of biological functions, such as antitumor and immunomodulating activities. In our previous studies, we developed a P. linteus grown on germinated brown rice (PBR) and found that organic solvent extracts of PBR possessed immunomodulating activity to regulate a balance of cytokine network in mice. The components of PBR are ergosterol peroxide, gamma-aminobutyric acid (GABA) and Beta-glucan. In this study, we demonstrate that an organic solvent extract of P. linteus grown on PBR induced apoptotic cell death through the induction of G(0)/G(1) arrest of cell cycle and the apoptosis via DNA fragmentation in human colon carcinoma HT-29 cells. Cell death induced by the extract of P. linteus grown on PBR was shown to be associated with the upregulation of p21(CIP1/WAF1), the downregulation of cyclin D1, anti-apoptotic protein, Bcl-2, the release of cytochrome c, and the activation of caspase-9, caspase-3 and caspase-8. This study suggests that the ethyl acetate extract of P. linteus grown on PBR induces apoptosis accompanied by cell cycle arrest at G(0)/G(1) phase and regulates apoptosis-regulatory proteins, which may be applicable to anticancer therapy.

Allspice and Clove As Source of Triterpene Acids Activating the G Protein-Coupled Bile Acid Receptor TGR5

PubMed Central

Ladurner, Angela; Zehl, Martin; Grienke, Ulrike; Hofstadler, Christoph; Faur, Nadina; Pereira, Fátima C.; Berry, David; Dirsch, Verena M.; Rollinger, Judith M.

2017-01-01

Worldwide, metabolic diseases such as obesity and type 2 diabetes have reached epidemic proportions. A major regulator of metabolic processes that gained interest in recent years is the bile acid receptor TGR5 (Takeda G protein-coupled receptor 5). This G protein-coupled membrane receptor can be found predominantly in the intestine, where it is mainly responsible for the secretion of the incretins glucagon-like peptide 1 (GLP-1) and peptide YY (PYY). The aim of this study was (i) to identify plant extracts with TGR5-activating potential, (ii) to narrow down their activity to the responsible constituents, and (iii) to assess whether the intestinal microbiota produces transformed metabolites with a different activity profile. Chenodeoxycholic acid (CDCA) served as positive control for both, the applied cell-based luciferase reporter gene assay for TGR5 activity and the biotransformation assay using mouse fecal slurry. The suitability of the workflow was demonstrated by the biotransformation of CDCA to lithocholic acid resulting in a distinct increase in TGR5 activity. Based on a traditional Tibetan formula, 19 plant extracts were selected and investigated for TGR5 activation. Extracts from the commonly used spices Syzygium aromaticum (SaroE, clove), Pimenta dioica (PdioE, allspice), and Kaempferia galanga (KgalE, aromatic ginger) significantly increased TGR5 activity. After biotransformation, only KgalE showed significant differences in its metabolite profile, which, however, did not alter its TGR5 activity compared to non-transformed KgalE. UHPLC-HRMS (high-resolution mass spectrometry) analysis revealed triterpene acids (TTAs) as the main constituents of the extracts SaroE and PdioE. Identification and quantification of TTAs in these two extracts as well as comparison of their TGR5 activity with reconstituted TTA mixtures allowed the attribution of the TGR5 activity to TTAs. EC50s were determined for the main TTAs, i.e., oleanolic acid (2.2 ± 1.6 μM), ursolic

Structure-activity relationship investigation of tertiary amine derivatives of cinnamic acid as acetylcholinesterase and butyrylcholinesterase inhibitors: compared with that of phenylpropionic acid, sorbic acid and hexanoic acid.

PubMed

Gao, Xiaohui; Tang, Jingjing; Liu, Haoran; Liu, Linbo; Kang, Lu; Chen, Wen

2018-12-01

In the present investigation, 48 new tertiary amine derivatives of cinnamic acid, phenylpropionic acid, sorbic acid and hexanoic acid (4d-6g, 10d-12g, 16d-18g and 22d-24g) were designed, synthesized and evaluated for the effect on AChE and BChE in vitro. The results revealed that the alteration of aminoalkyl types and substituted positions markedly influences the effects in inhibiting AChE. Almost of all cinnamic acid derivatives had the most potent inhibitory activity than that of other acid derivatives with the same aminoalkyl side chain. Unsaturated bond and benzene ring in cinnamic acid scaffold seems important for the inhibitory activity against AChE. Among them, compound 6g revealed the most potent AChE inhibitory activity (IC 50 value: 3.64 µmol/L) and highest selectivity over BChE (ratio: 28.6). Enzyme kinetic study showed that it present a mixed-type inhibition against AChE. The molecular docking study suggested that it can bind with the catalytic site and peripheral site of AChE.

Mechanism of the contractile effects of galantide and Galanin(1-14) [alpha-aminobutyric acid]scyliorhinin-I in rat isolated fundus strips.

PubMed

Korolkiewicz, Roman P; Konstanski, Zdziaław; Rekowski, Piotr; Szyk, Agnieszka; Ruczyński, Jaroslaw; Dabrowski, Jaroslaw; Ujda, Marek; Korolkiewicz, Konstanty Zbigniew; Petrusewicz, Jacek

2002-01-01

The study was undertaken to establish the pharmacological basis of the stimulatory activity of galantide (M15) and galanin(1-14)-(a-aminobutyric acid8-[Abu8])scyliorhinin-I [Scy-I] in gastric smooth muscle. Isotonic contractions of the isolated, longitudinal rat gastric fundus strips were recorded. Galanin, galanin(1-15)-NH2, M15 and galanin(1-14)-[Abu8]Scy-I elicited concentration-dependent contractions. Their EC50s equaled 12.95, 174, 70.06 and 187 nM respectively. Hill's coefficients for galanin and galanin(1-15)-NH2 were not different from unity, indicating an interaction of one peptide molecule with one receptor according to the principles of classical receptor theory. Hill's coefficients were 0.73 and 1.56 for M15 and galanin (1-14)-[Abu8]Scy-I, respectively, a value significantly different from unity. Cold-storage denervation, tetrodotoxin-TTX (1 mM), spantide (100 mM) and NK1-3 receptor antagonists SR140333, 48968, 142801 (up to 10 mM) notably diminished M15, galanin(1-14)-[Abu8]Scy-I, SP(5-11) and [Abu8]-Scy-I evoked contractions without affecting activities of galanin and galanin(1-15)-NH2. Additionally, cross-desensitization experiments attenuated activity of M15 and galanin(1-14)-[Abu8]Scy-I without any noticeable action on galanin or galanin(1-15)-NH2. The action of chimeric peptides on the smooth muscle of the rat gastrointestinal tract depended not only on the myogenic interaction of those peptides with galanin binding sites, but also on the activation of tachykinin receptors or the release of endogenous mediators from the presynaptic terminals.

Arabidopsis aldehyde dehydrogenase 10 family members confer salt tolerance through putrescine-derived 4-aminobutyrate (GABA) production.

PubMed

Zarei, Adel; Trobacher, Christopher P; Shelp, Barry J

2016-10-11

Polyamines represent a potential source of 4-aminobutyrate (GABA) in plants exposed to abiotic stress. Terminal catabolism of putrescine in Arabidopsis thaliana involves amine oxidase and the production of 4-aminobutanal, which is a substrate for NAD + -dependent aminoaldehyde dehydrogenase (AMADH). Here, two AMADH homologs were chosen (AtALDH10A8 and AtALDH10A9) as candidates for encoding 4-aminobutanal dehydrogenase activity for GABA synthesis. The two genes were cloned and soluble recombinant proteins were produced in Escherichia coli. The pH optima for activity and catalytic efficiency of recombinant AtALDH10A8 with 3-aminopropanal as substrate was 10.5 and 8.5, respectively, whereas the optima for AtALDH10A9 were approximately 9.5. Maximal activity and catalytic efficiency were obtained with NAD + and 3-aminopropanal, followed by 4-aminobutanal; negligible activity was obtained with betaine aldehyde. NAD + reduction was accompanied by the production of GABA and β-alanine, respectively, with 4-aminobutanal and 3-aminopropanal as substrates. Transient co-expression systems using Arabidopsis cell suspension protoplasts or onion epidermal cells and several organelle markers revealed that AtALDH10A9 was peroxisomal, but AtALDH10A8 was cytosolic, although the N-terminal 140 amino acid sequence of AtALDH10A8 localized to the plastid. Root growth of single loss-of-function mutants was more sensitive to salinity than wild-type plants, and this was accompanied by reduced GABA accumulation.

Contribution of the activated catalase to oxidative stress resistance and γ-aminobutyric acid production in Lactobacillus brevis.

PubMed

Lyu, Changjiang; Hu, Sheng; Huang, Jun; Luo, Maiqi; Lu, Tao; Mei, Lehe; Yao, Shanjing

2016-12-05

Lactic acid bacteria (LAB) are generally sensitive to H 2 O 2 , a compound which can paradoxically produce themselves and lead to the growth arrest and cell death. To counteract the potentially toxic effects of this compound, the gene katE encoding a heme-dependent catalase (CAT) belonging to the family of monofunctional CATs was cloned from Lactobacillus brevis CGMCC1306. The enhanced homologous CAT expression was achieved using the NICE system. L. brevis cells with overexpressed CAT showed 685-fold and 823-fold higher survival when exposed to 30mmol/L of H 2 O 2 and long-term aerated stress (after 72h), respectively, than that of the wild type cells. Furtherly, the effects of activated CAT on GABA production in L. brevis were investigated. A GABA production level of 66.4g/L was achieved using two-step biotransformation that successively employed the growing and resting cells derived from engineering L. brevis CAT. These results demonstrated clearly that overexpression of the KatE gene in L. brevis led to a marked increased survival in oxidizing environment, and shed light on a novel feasible approach to enhance the GABA production level by improving the antioxidative properties. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification, Purification, and Characterization of a Novel Amino Acid Racemase, Isoleucine 2-Epimerase, from Lactobacillus Species

PubMed Central

Mutaguchi, Yuta; Ohmori, Taketo; Wakamatsu, Taisuke; Doi, Katsumi

2013-01-01

Accumulation of d-leucine, d-allo-isoleucine, and d-valine was observed in the growth medium of a lactic acid bacterium, Lactobacillus otakiensis JCM 15040, and the racemase responsible was purified from the cells and identified. The N-terminal amino acid sequence of the purified enzyme was GKLDKASKLI, which is consistent with that of a putative γ-aminobutyrate aminotransferase from Lactobacillus buchneri. The putative γ-aminobutyrate aminotransferase gene from L. buchneri JCM 1115 was expressed in recombinant Escherichia coli and then purified to homogeneity. The enzyme catalyzed the racemization of a broad spectrum of nonpolar amino acids. In particular, it catalyzed at high rates the epimerization of l-isoleucine to d-allo-isoleucine and d-allo-isoleucine to l-isoleucine. In contrast, the enzyme showed no γ-aminobutyrate aminotransferase activity. The relative molecular masses of the subunit and native enzyme were estimated to be about 49 kDa and 200 kDa, respectively, indicating that the enzyme was composed of four subunits of equal molecular masses. The Km and Vmax values of the enzyme for l-isoleucine were 5.00 mM and 153 μmol·min−1·mg−1, respectively, and those for d-allo-isoleucine were 13.2 mM and 286 μmol·min−1·mg−1, respectively. Hydroxylamine and other inhibitors of pyridoxal 5′-phosphate-dependent enzymes completely blocked the enzyme activity, indicating the enzyme requires pyridoxal 5′-phosphate as a coenzyme. This is the first evidence of an amino acid racemase that specifically catalyzes racemization of nonpolar amino acids at the C-2 position. PMID:24039265

Changing epidemiology of rotavirus G-types circulating in Hong Kong, China.

PubMed

Lo, Janice Yee Chi; Szeto, Kai Cheung; Tsang, Dominic Ngai Chong; Leung, Kwok Hung; Lim, Wilina Wei Ling

2005-01-01

Group A rotaviruses are the most common cause of severe diarrhoeal disease in young children worldwide. The development of a vaccine is advocated by the World Health Organization. Obtaining local baseline information regarding rotavirus strain variation is important to ensure matching of circulating and vaccine strains. The current study was undertaken to determine the epidemiology of rotavirus G-types in Hong Kong in anticipation of a vaccination program. From 2001 to 2002 over a period of one year, diarrhoeal stool specimens known to be positive for rotavirus were subjected to G-typing by reverse transcriptase-polymerase chain reaction using nested type-specific primers. Rotavirus G-type distribution was correlated with patient demographics. Among 747 rotavirus positive stool specimens, 723 strains could be G-typed as G1 (302, 40.4%), G2 (128, 17.1%), G3 (231, 30.9%), G4 (24, 3.2%), and G9 (38, 5.1%). G1 strains were found predominantly in those 5 years old or younger (P < 0.0001), while G2 strains were more prevalent among those over 5 years of age (P < 0.001). When compared with similar studies in 1983 to 1984 and 1999 to 2000, there were significant changes in the prevalence of various G-types, with consistent detection of G9 strains in the current study. It is concluded that rotavirus G-type distribution in Hong Kong has varied with time. Continuous monitoring of the epidemiology of rotavirus is important, especially in anticipation of the introduction of a vaccine, in order to document its impact and to ensure its continued effectiveness. Copyright 2005 Wiley-Liss, Inc.

Influence of carbon source and inoculum type on anaerobic biomass adhesion on polyurethane foam in reactors fed with acid mine drainage.

PubMed

Rodriguez, Renata P; Zaiat, Marcelo

2011-04-01

This paper analyzes the influence of carbon source and inoculum origin on the dynamics of biomass adhesion to an inert support in anaerobic reactors fed with acid mine drainage. Formic acid, lactic acid and ethanol were used as carbon sources. Two different inocula were evaluated: one taken from an UASB reactor and other from the sediment of a uranium mine. The values of average colonization rates and the maximum biomass concentration (C(max)) were inversely proportional to the number of carbon atoms in each substrate. The highest C(max) value (0.35 g TVS g(-1) foam) was observed with formic acid and anaerobic sludge as inoculum. Maximum colonization rates (v(max)) were strongly influenced by the type of inoculum when ethanol and lactic acid were used. For both carbon sources, the use of mine sediment as inoculum resulted in a v(max) of 0.013 g TVS g(-1) foam day(-1), whereas 0.024 g TVS g(-1) foam day(-1) was achieved with anaerobic sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.

Studying the loading effect of acidic type antioxidant on amorphous silica nanoparticle carriers

NASA Astrophysics Data System (ADS)

Ravinayagam, Vijaya; Rabindran Jermy, B.

2017-06-01

The study investigates the suitable nanosilica carriers to transport acidic type cargo molecules for potential targeted drug delivery application. Using phenolic acidic type antioxidant gallic acid (GA) as model compound, the present study investigates the loading effect of GA (0.3-15.9 mmol GA g-1 support) on textural characteristics of amorphous silica nanoparticles such as Q10 silica (1D), structured two-dimensional Si-MCM-41 (2D), and three-dimensional Si-SBA-16 (3D). The variation in the nature of textures after GA loading was analyzed using X-ray diffraction, N2 adsorption, FT-IR, scanning electron microscopy with energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. Among the nanocarriers, high adsorption of GA was found in the following order: Si-SBA-16 (3D)˜Si-KIT-6 (3D) > Si-MCM-41 (2D) > ultralarge pore FDU-12 (ULPFDU-12; 3D) > Q10 (1D)˜mesostructured cellular silica foam (MSU-F). 3D-type silicas Si-SBA-16 and KIT-6 were shown to maintain structural integrity at acidic condition (pH ˜3) and accommodate GA in non-crystalline form. In the case of ULPFDU-12 and MSU-F cellular foam, only crystalline deposition of GA occurs with a significant variation in the surface area and pore volume. [Figure not available: see fulltext.

Effect of Phenolic Compounds from Elderflowers on Glucose- and Fatty Acid Uptake in Human Myotubes and HepG2-Cells.

PubMed

Ho, Giang Thanh Thi; Kase, Eili Tranheim; Wangensteen, Helle; Barsett, Hilde

2017-01-06

Type 2 diabetes (T2D) is manifested by progressive metabolic impairments in tissues such as skeletal muscle and liver, and these tissues become less responsive to insulin, leading to hyperglycemia. In the present study, stimulation of glucose and oleic acid uptake by elderflower extracts, constituents and metabolites were tested in vitro using the HepG2 hepatocellular liver carcinoma cell line and human skeletal muscle cells. Among the crude extracts, the 96% EtOH extract showed the highest increase in glucose and oleic acid uptake in human skeletal muscle cells and HepG2-cells. The flavonoids and phenolic acids contained therein were potent stimulators of glucose and fatty acid uptake in a dose-dependent manner. Most of the phenolic constituents and several of the metabolites showed high antioxidant activity and showed considerably higher α-amylase and α-glucosidase inhibition than acarbose. Elderflower might therefore be valuable as a functional food against diabetes.

2-Furoylmethyl amino acids as indicators of Maillard reaction during the elaboration of black garlic.

PubMed

Ríos-Ríos, Karina L; Vázquez-Barrios, M Estela; Gaytán-Martínez, Marcela; Olano, Agustín; Montilla, Antonia; Villamiel, Mar

2018-02-01

This study reports the formation of 2-furomethyl-amino acids (2-FM-AA) as indicators of Maillard reaction (MR) in black garlic elaboration, followed by the determination of furosine by ion-pair RP-HPLC-UV. The method was assessed for accuracy, repeatability and detection and quantitation limits indicating its adequacy. Traditional procedure of black garlic obtainment and the inclusion of convective drying (CDP) and ohmic heating (OHP) were assayed. For comparison purposes, three commercial black garlic samples were used. Together with furosine (2-FM-lysine), 2-furoylmethyl-γ-aminobutyric acid and 2-FM-arginine were detected. Levels of furosine were higher in CDP (46.6-110.1mg/100g protein) than in OHP (13.7-42.0mg/100g protein) samples, probably due to the most severe processing conditions used in the former. These results highlight the suitability of 2-FM-AA as chemical indicators to monitor the process of black garlic elaboration in order to obtain high quality products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Genetics Home Reference: congenital bile acid synthesis defect type 1

MedlinePlus

... type 1 Congenital bile acid synthesis defect type 1 Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Congenital bile acid synthesis defect type 1 ...

Role of a gamma-aminobutryic acid (GABA) receptor mutation in the evolution and spread of Diabrotica virgifera virgifera resistance to cyclodiene insecticides

USDA-ARS?s Scientific Manuscript database

An alanine to serine amino acid substitution within the Rdl subunit of the gamma-aminobutyric acid (GABA) receptor confers resistance to cyclodiene insecticides in many species. The corn rootworm, Diabrotica virgifera virgifera, is a damaging pest of cultivated corn that was partially controlled by ...

Guanine base stacking in G-quadruplex nucleic acids

PubMed Central

Lech, Christopher Jacques; Heddi, Brahim; Phan, Anh Tuân

2013-01-01

G-quadruplexes constitute a class of nucleic acid structures defined by stacked guanine tetrads (or G-tetrads) with guanine bases from neighboring tetrads stacking with one another within the G-tetrad core. Individual G-quadruplexes can also stack with one another at their G-tetrad interface leading to higher-order structures as observed in telomeric repeat-containing DNA and RNA. In this study, we investigate how guanine base stacking influences the stability of G-quadruplexes and their stacked higher-order structures. A structural survey of the Protein Data Bank is conducted to characterize experimentally observed guanine base stacking geometries within the core of G-quadruplexes and at the interface between stacked G-quadruplex structures. We couple this survey with a systematic computational examination of stacked G-tetrad energy landscapes using quantum mechanical computations. Energy calculations of stacked G-tetrads reveal large energy differences of up to 12 kcal/mol between experimentally observed geometries at the interface of stacked G-quadruplexes. Energy landscapes are also computed using an AMBER molecular mechanics description of stacking energy and are shown to agree quite well with quantum mechanical calculated landscapes. Molecular dynamics simulations provide a structural explanation for the experimentally observed preference of parallel G-quadruplexes to stack in a 5′–5′ manner based on different accessible tetrad stacking modes at the stacking interfaces of 5′–5′ and 3′–3′ stacked G-quadruplexes. PMID:23268444

The Pseudomonas syringae type III effector HopG1 targets mitochondria, alters plant development, and suppresses plant innate immunity

PubMed Central

Block, Anna; Guo, Ming; Li, Guangyong; Elowsky, Christian; Clemente, Thomas E.; Alfano, James R.

2009-01-01

Summary The bacterial plant pathogen Pseudomonas syringae uses a type III protein secretion system to inject type III effectors into plant cells. Primary targets of these effectors appear to be effector-triggered immunity (ETI) and pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). The type III effector HopG1 is a suppressor of ETI that is broadly conserved in bacterial plant pathogens. Here we show that HopG1 from P. syringae pv. tomato DC3000 also suppresses PTI. Interestingly, HopG1 localizes to plant mitochondria, suggesting that its suppression of innate immunity may be linked to a perturbation of mitochondrial function. While HopG1 possesses no obvious mitochondrial signal peptide, its N-terminal two-thirds was sufficient for mitochondrial localization. A HopG1-GFP fusion lacking HopG1’s N-terminal 13 amino acids was not localized to the mitochondria reflecting the importance of the N-terminus for targeting. Constitutive expression of HopG1 in Arabidopsis thaliana, Nicotiana tabacum (tobacco) and Lycopersicon esculentum (tomato) dramatically alters plant development resulting in dwarfism, increased branching and infertility. Constitutive expression of HopG1 in planta leads to reduced respiration rates and an increased basal level of reactive oxygen species. These findings suggest that HopG1’s target is mitochondrial and that effector/target interaction promotes disease by disrupting mitochondrial functions. PMID:19863557

Variation in plasma amino acid concentrations during a cycling competition.

PubMed

Medelli, J; Lounana, J; Hill, D

2003-06-01

The variations in plasma concentrations of 24 amino acids (AAs) were measured, taking into account modifications in plasma volume, in 7 male subjects, professional cyclists, during the first 2 stages (EI and EII) of the competition "4 Days of Dunkirk 1999". Blood samples were taken before the start and at the end of each stage. At the end of EI a significant reduction (p<0.02) in alpha-aminobutyric acid was observed (-38%) and a significant increase (Wilcoxon 0.01aminobutyric acid (33%), arginine (-21%), cystine (-15%), glycocholic acid (26%), hydroxyproline (-28%), leucine (-17%), lysine (-26%), methionine (-19%), threonine (-15%) and valine (-16%). The recovery period was characterised by increases in previously reduced AAs and vice versa. These results show that cellular use of plasma AAs in the endurance cyclist could differ between the first hours of competition and the subsequent stages, possibly in relation to the gradual increase in stress level as the stages progress; they also suggest that appropriate consideration should be given to the quality of protein inputs in the nutrition of cyclists involved in a high-level stage competition.

Plasma amino acid profiles in healthy East Asian subpopulations living in Japan.

PubMed

Nakamura, Hidehiro; Nishikata, Natsumi; Kawai, Nobuhiro; Imaizumi, Akira; Miyano, Hiroshi; Mori, Maiko; Yamamoto, Hiroshi; Noguchi, Yasushi

2016-01-01

Profiles of plasma free amino acids (PFAAs) have been utilized as biomarkers to detect various diseases. However, few studies have investigated whether ethnicity or specific subpopulations within East Asia influence PFAA concentrations. A total of 95 healthy volunteers living in Japan, including 31 Japanese individuals, 36 Korean individuals and 28 Chinese individuals, were enrolled. Participants' PFAA levels were measured by high-performance liquid chromatography mass spectrometry, and the effects of factors such as sex, age, body mass index (BMI) and subpopulation on PFAA profiles were analyzed. With the exception of glutamine and α-aminobutyric acid, there were no significant differences among the three examined subpopulations with respect to either the means or the distributions of PFAA concentrations. A multiple regression analysis revealed that most of the PFAA concentrations were significantly related to sex. Ornithine concentrations, glutamate concentrations, and glutamine and α-aminobutyric acid concentrations were significantly associated with age, BMI, and Chinese subpopulation, respectively. The study results indicate that the contributions of subpopulation within East Asia to PFAA profiles are small, particularly relative to the contributions provided by sex. © 2015 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.

Acidic tumor microenvironment and pH-sensing G protein-coupled receptors.

PubMed

Justus, Calvin R; Dong, Lixue; Yang, Li V

2013-12-05

The tumor microenvironment is acidic due to glycolytic cancer cell metabolism, hypoxia, and deficient blood perfusion. It is proposed that acidosis in the tumor microenvironment is an important stress factor and selection force for cancer cell somatic evolution. Acidic pH has pleiotropic effects on the proliferation, migration, invasion, metastasis, and therapeutic response of cancer cells and the function of immune cells, vascular cells, and other stromal cells. However, the molecular mechanisms by which cancer cells and stromal cells sense and respond to acidic pH in the tumor microenvironment are poorly understood. In this article the role of a family of pH-sensing G protein-coupled receptors (GPCRs) in tumor biology is reviewed. Recent studies show that the pH-sensing GPCRs, including GPR4, GPR65 (TDAG8), GPR68 (OGR1), and GPR132 (G2A), regulate cancer cell metastasis and proliferation, immune cell function, inflammation, and blood vessel formation. Activation of the proton-sensing GPCRs by acidosis transduces multiple downstream G protein signaling pathways. Since GPCRs are major drug targets, small molecule modulators of the pH-sensing GPCRs are being actively developed and evaluated. Research on the pH-sensing GPCRs will continue to provide important insights into the molecular interaction between tumor and its acidic microenvironment and may identify new targets for cancer therapy and chemoprevention.

Preparation of dibenzo[e,g]isoindol-1-ones via Scholl-type oxidative cyclization reactions.

PubMed

van Loon, Amy A; Holton, Maeve K; Downey, Catherine R; White, Taryn M; Rolph, Carly E; Bruening, Stephen R; Li, Guanqun; Delaney, Katherine M; Pelkey, Sarah J; Pelkey, Erin T

2014-09-05

A flexible synthesis of dibenzo[e,g]isoindol-1-ones has been developed. Dibenzo[e,g]isoindol-1-ones represent simplified benzenoid analogues of biological indolo[2,3-a]pyrrolo[3,4-c]carbazol-5-ones (indolocarbazoles), compounds that have demonstrated a wide range of biological activity. The synthesis of the title compounds involved tetramic acid sulfonates. Different aryl groups were introduced at C4 of the heterocyclic ring via Suzuki-Miyaura cross-coupling reactions. Finally, mild Scholl-type oxidative cyclizations mediated by phenyliodine(III) bis(trifluoroacetate) (PIFA) converted some of the latter compounds into the corresponding dibenzo[e,g]isoindol-1-ones. A systematic study of the oxidative cyclization revealed the following reactivity trend: 3,4-dimethoxyphenyl ≫ 3-methoxyphenyl > 3,4,5-trimethoxyphenyl > 4-methoxyphenyl ≈ phenyl. Overall, the oxidative cyclization required at least two methoxy groups distributed in the aromatic rings, at least one of which had to be located para to the site of the cyclization.

Preparation of Dibenzo[e,g]isoindol-1-ones via Scholl-Type Oxidative Cyclization Reactions

PubMed Central

2015-01-01

A flexible synthesis of dibenzo[e,g]isoindol-1-ones has been developed. Dibenzo[e,g]isoindol-1-ones represent simplified benzenoid analogues of biological indolo[2,3-a]pyrrolo[3,4-c]carbazol-5-ones (indolocarbazoles), compounds that have demonstrated a wide range of biological activity. The synthesis of the title compounds involved tetramic acid sulfonates. Different aryl groups were introduced at C4 of the heterocyclic ring via Suzuki–Miyaura cross-coupling reactions. Finally, mild Scholl-type oxidative cyclizations mediated by phenyliodine(III) bis(trifluoroacetate) (PIFA) converted some of the latter compounds into the corresponding dibenzo[e,g]isoindol-1-ones. A systematic study of the oxidative cyclization revealed the following reactivity trend: 3,4-dimethoxyphenyl ≫ 3-methoxyphenyl > 3,4,5-trimethoxyphenyl > 4-methoxyphenyl ≈ phenyl. Overall, the oxidative cyclization required at least two methoxy groups distributed in the aromatic rings, at least one of which had to be located para to the site of the cyclization. PMID:25138638

Type 1 5'-deiodinase activity is inhibited by oxidative stress and restored by alpha-lipoic acid in HepG2 cells.

PubMed

Chen, Kanjun; Yan, Biao; Wang, Fei; Wen, Feiting; Xing, Xingan; Tang, Xue; Shi, Yonghui; Le, Guowei

2016-04-08

3,3',5-triiodothyronine (T3) is largely generated from thyroxine (T4) by the catalysis of deiodinases in peripheral tissues. Emerging evidences have indicated its broad participation in regulating various metabolic process via protecting tissues from oxidative stress and improving cellular antioxidant capacity. However, the potential correlation between the oxidative stress and conversion of T4 to T3 is still unclear. In the present study, the effects of T3 and T4 on redox homeostasis in HepG2 cells pre-treated with H2O2 was investigated. It revealed that T3 significantly rescued the apoptotic cell death, consistent with an upregulation of cell antioxidant ability and reduction of ROS accumulation while T4 did not. Afterwards, we examined the enzyme activity and mRNA expression of type 1 5'-deiodianse (DIO1), T3 and rT3 level and found that H2O2 reduced both DIO1 activity and expression in a dose-dependent manner, which consequently declined T3 and rT3 generation. Alpha-lipoic acid (LA) treatment notably restored DIO1 activity, T3 and rT3 level, as well as transcriptional abnormalities of inflammation-associated genes. It suggests that oxidative stress may reduce DIO1 activity by an indirect way like activating cellular inflammatory responses. All these results indicate that the oxidative stress downregulates the conversion of T4 to T3 through DIO1 function in HepG2 cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of different amino acid derivatives and analysis of rat brain microdialysates by liquid chromatography tandem mass spectrometry.

PubMed

Uutela, Päivi; Ketola, Raimo A; Piepponen, Petteri; Kostiainen, Risto

2009-02-09

The efficiencies of three derivatisation reagents that react with either the amine (9-fluorenylmethyl chloroformate (FMOC)) or the carboxylic acid group (butanol) of amino acid or with both types of functional groups (propyl chloroformate) were compared in the analysis of amino acids by liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS). Separation of 20 amino acids derivatised with these three reagents was studied on reversed-phase chromatography. Linearity, repeatability and limits of detection of the LC-ESI-MS/MS method were determined by analysing FMOC-, butanol- and propyl chloroformate-derivatised lysine, beta-aminobutyric acid, threonine and glutamic acid. The limits of detection for the derivatised amino acids (7.5-75fmol) were as much as 2-60 times lower than those of the corresponding underivatised molecules. The best linearity was observed for amino acids derivatised with propyl chloroformate or butanol (r(2)=0.996-0.999, range=100-8500nmolL(-1)). Propyl chloroformate was the best suited of the reagents tested for the analysis of amino acids with LC-MS/MS and was used for the analysis of amino acids in rat brain microdialysis samples.

HPLC-Based Activity Profiling for GABAA Receptor Modulators in Searsia pyroides Using a Larval Zebrafish Locomotor Assay.

PubMed

Moradi-Afrapoli, Fahimeh; van der Merwe, Hannes; De Mieri, Maria; Wilhelm, Anke; Stadler, Marco; Zietsman, Pieter C; Hering, Steffen; Swart, Kenneth; Hamburger, Matthias

2017-10-01

A dichloromethane extract from leaves of Searsia pyroides potentiated gamma aminobutyric acid-induced chloride currents by 171.8 ± 54% when tested at 100 µg/mL in Xenopus oocytes transiently expressing gamma aminobutyric acid type A receptors composed of α 1 β 2 γ 2 s subunits. In zebrafish larvae, the extract significantly lowered pentylenetetrazol-provoked locomotion when tested at 4 µg/mL. Active compounds of the extract were tracked with the aid of HPLC-based activity profiling utilizing a previously validated zebrafish larval locomotor activity assay. From two active HPLC fractions, compounds 1  -  3 were isolated. Structurally related compounds 4  -  6 were purified from a later eluting inactive HPLC fraction. With the aid of 1 H and 13 C NMR and high-resolution mass spectrometry, compounds 1  -  6 were identified as analogues of anacardic acid. Compounds 1  -  3 led to a concentration-dependent decrease of pentylenetetrazol-provoked locomotion in the zebrafish larvae model, while 4  -  6 were inactive. Compounds 1  -  3 enhanced gamma aminobutyric acid-induced chloride currents in Xenopus oocytes in a concentration-dependent manner, while 4  -  6 only showed marginal enhancements of gamma aminobutyric acid-induced chloride currents. Compounds 2, 3 , and 5 have not been reported previously. Georg Thieme Verlag KG Stuttgart · New York.

Effects of propofol, midazolam and thiopental sodium on outcome and amino acids accumulation in focal cerebral ischemia-reperfusion in rats.

PubMed

Chen, Lianhua; Gong, Qinyan; Xiao, Changsi

2003-02-01

To investigate the effects of propofol, midazolam and thiopental sodium on outcomes and amino acid accumulation in focal cerebral ischemia-reperfusion in rats. Male Sprague Dawley (SD) rats were scheduled to undergo 3-hour middle cerebral artery occlusion by intraluminal suture and 24-hour reperfusion. Neurologic outcomes were scored on a 0-5 grading scale. Infarct volume was shown with triphenyltetrazolium chloride staining and measured by an image analysis system. Concentrations of various amino acids (aspartate, glutamate, glycine, taurine, and gama-aminobutyric acid) were measured after 3 hours of reperfusion using high performance liquid chromatography. Propofol, midazolam and thiopental sodium were given intraperitoneally at the beginning of reperfusion. Both propofol and midazolam attenuated neurological deficits and reduced infarct and edema volumes. Propofol showed better neurological protection than midazolam while thiopental sodium did not exhibit any protective effect. Both propofol and midazolam decreased excitatory amino acids accumulation, while propofol increased gama-aminobutyric acid accumulation in ischemic areas in reperfusion. Propofol and midazolam, but not thiopental sodium, may provide protective effects against reperfusion induced injury in rats subjected to focal cerebral ischemia. This neurological protection may be due to the acceleration of excitatory amino acids elimination in reperfusion.

Modulation of the release of norepinephrine by gamma-aminobutyric acid and morphine in the frontal cerebral cortex of the rat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peoples, R.W.

1989-01-01

Agents that enhance gamma-aminobutyric acid, or GABA, neurotransmission modulate certain effects of opioids, such as analgesia. Opioid analgesia is mediated in part by norepinephrine in the forebrain. In this study, the interactions between morphine and GABAergic agents on release of ({sup 3}H) norepinephrine from rat frontal cerebral cortical slices were examined. GABA, 5 {times} 10{sup {minus}5}-10{sup {minus}3} M, enhanced potassium stimulated ({sup 3}H) norepinephrine release and reversed the inhibitory effect of morphine in a noncompetitive manner. GABA did not enhance release of ({sup 3}H) norepinephrine stimulated by the calcium ionophore A23187. The effect of GABA was reduced by the GABA{submore » A} receptor antagonists bicuculline methiodide or picrotoxin, and by the selective inhibitor of GABA uptake SKF 89976A, but was blocked completely only when bicuculline methiodide and SKF 89976A were used in combination. The GABA{sub A} agonist muscimol, 10{sup {minus}4} M, mimicked the effect of GABA, but the GABA{sub B} agonist ({plus minus})baclofen, 10{sup {minus}4} M, did not affect the release of ({sup 3}H) norepinephrine in the absence or the presence of morphine. Thus GABA appears to produce this effect by stimulating GABA uptake and GABA{sub A}, but not GABA{sub B}, receptors. In contrast to the results that would be predicted for an event involving GABA{sub A} receptors, however, the effect of GABA did not desensitize, and benzodiazepine agonists did not enhance the effect of GABA at any concentration tested between 10{sup {minus}8} and 10{sup {minus}4} M. Thus these receptors may constitute a subclass of GABA{sub A} receptors. These results support a role of GABA uptake and GABA{sub A} receptors in enhancing the release of norepinephrine and modulating its inhibition by opioids in the frontal cortex of the rat.« less

Elevated prefrontal cortex γ-aminobutyric acid and glutamate-glutamine levels in schizophrenia measured in vivo with proton magnetic resonance spectroscopy.

PubMed

Kegeles, Lawrence S; Mao, Xiangling; Stanford, Arielle D; Girgis, Ragy; Ojeil, Najate; Xu, Xiaoyan; Gil, Roberto; Slifstein, Mark; Abi-Dargham, Anissa; Lisanby, Sarah H; Shungu, Dikoma C

2012-05-01

Postmortem studies have found evidence of γ-aminobutyric acid (GABA) deficits in fast-spiking, parvalbumin-positive interneurons in the prefrontal cortex in schizophrenia. Magnetic resonance spectroscopy studies in unmedicated patients have reported glutamine or glutamate-glutamine (Glx) elevations in this region. Abnormalities in these transmitters are thought to play a role in cognitive impairments in the illness. To measure GABA and Glx levels in vivo in 2 prefrontal brain regions in unmedicated and medicated patients with schizophrenia and healthy controls. Case-control study. Inpatient psychiatric research unit and associated outpatient clinic. Sixteen unmedicated patients with schizophrenia, 16 medicated patients, and 22 healthy controls matched for age, sex, ethnicity, parental socioeconomic status, and cigarette smoking. Proton magnetic resonance spectroscopy with a 3-T system and the J-edited spin-echo difference method. The GABA and Glx levels were measured in the dorsolateral and medial prefrontal cortex and normalized to the simultaneously acquired water signal. Working memory performance was assessed in all subjects. The GABA and Glx concentrations determined by proton magnetic resonance spectroscopy. In the medial prefrontal cortex region, 30% elevations were found in GABA (P = .02) and Glx (P = .03) levels in unmedicated patients compared with controls. There were no alterations in the medicated patients or in either group in the dorsolateral prefrontal cortex. Both regions showed correlations between GABA and Glx levels in patients and controls. No correlations with working memory performance were found. To our knowledge, this study presents the first GABA concentration measurements in unmedicated patients with schizophrenia, who showed elevations in both GABA and Glx levels in the medial prefrontal cortex but not the dorsolateral prefrontal cortex. Medicated patients did not show these elevations, suggesting possible normalization of levels with

Linkage-specific sialic acid derivatization for MALDI-TOF-MS profiling of IgG glycopeptides.

PubMed

de Haan, Noortje; Reiding, Karli R; Haberger, Markus; Reusch, Dietmar; Falck, David; Wuhrer, Manfred

2015-08-18

Glycosylation is a common co- and post-translational protein modification, having a large influence on protein properties like conformation and solubility. Furthermore, glycosylation is an important determinant of efficacy and clearance of biopharmaceuticals such as immunoglobulin G (IgG). Matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF)-mass spectrometry (MS) shows potential for the site-specific glycosylation analysis of IgG at the glycopeptide level. With this approach, however, important information about glycopeptide sialylation is not duly covered because of in-source and metastable decay of the sialylated species. Here, we present a highly repeatable sialic acid derivatization method to allow subclass-specific MALDI-TOF-MS analysis of tryptic IgG glycopeptides. The method, employing dimethylamidation with the carboxylic acid activator 1-ethyl-3-(3-dimethylamino)propyl)carbodiimide (EDC) and the catalyst 1-hydroxybenzotriazole (HOBt), results in different masses for the functionally divergent α2,3- and α2,6-linked sialic acids. Respective lactonization and dimethylamidation leads to their direct discrimination in MS and importantly, both glycan and peptide moieties reacted in a controlled manner. In addition, stabilization allowed the acquisition of fragmentation spectra informative with respect to glycosylation and peptide sequence. This was in contrast to fragmentation spectra of underivatized samples, which were dominated by sialic acid loss. The method allowed the facile discrimination and relative quantitation of IgG Fc sialylation in therapeutic IgG samples. The method has considerable potential for future site- and sialic acid linkage-specific glycosylation profiling of therapeutic antibodies, as well as for subclass-specific biomarker discovery in clinical IgG samples derived from plasma.

Acid-induced exchange of the imino proton in G.C pairs.

PubMed Central

Nonin, S; Leroy, J L; Gueron, M

1996-01-01

Acid-induced catalysis of imino proton exchange in G.C pairs of DNA duplexes is surprisingly fast, being nearly as fast as for the isolated nucleoside, despite base-pair dissociation constants in the range of 10(-5) at neutral or basic pH. It is also observed in terminal G.C pairs of duplexes and in base pairs of drug-DNA complexes. We have measured imino proton exchange in deoxyguanosine and in the duplex (ATATAGATCTATAT) as a function of pH. We show that acid-induced exchange can be assigned to proton transfer from N7-protonated guanosine to cytidine in the open state of the pair. This is faster than transfer from neutral guanosine (the process of intrinsic catalysis previously characterized at neutral ph) due to the lower imino proton pK of the protonated form, 7.2 instead of 9.4. Other interpretations are excluded by a study of exchange catalysis by formiate and cytidine as exchange catalysts. The cross-over pH between the regimes of pH-independent and acid-induced exchange rates is more basic in the case of base pairs than in the mononucleoside, suggestive of an increase by one to two decades in the dissociation constant of the base pair upon N7 protonation of G. Acid-induced catalysis is much weaker in A.T base pairs, as expected in view of the low pK for protonation of thymidine. PMID:8604298

Acid-induced exchange of the imino proton in G.C pairs.

PubMed

Nonin, S; Leroy, J L; Gueron, M

1996-02-15

Acid-induced catalysis of imino proton exchange in G.C pairs of DNA duplexes is surprisingly fast, being nearly as fast as for the isolated nucleoside, despite base-pair dissociation constants in the range of 10(-5) at neutral or basic pH. It is also observed in terminal G.C pairs of duplexes and in base pairs of drug-DNA complexes. We have measured imino proton exchange in deoxyguanosine and in the duplex (ATATAGATCTATAT) as a function of pH. We show that acid-induced exchange can be assigned to proton transfer from N7-protonated guanosine to cytidine in the open state of the pair. This is faster than transfer from neutral guanosine (the process of intrinsic catalysis previously characterized at neutral ph) due to the lower imino proton pK of the protonated form, 7.2 instead of 9.4. Other interpretations are excluded by a study of exchange catalysis by formiate and cytidine as exchange catalysts. The cross-over pH between the regimes of pH-independent and acid-induced exchange rates is more basic in the case of base pairs than in the mononucleoside, suggestive of an increase by one to two decades in the dissociation constant of the base pair upon N7 protonation of G. Acid-induced catalysis is much weaker in A.T base pairs, as expected in view of the low pK for protonation of thymidine.

Structural basis for cyclization specificity of two Azotobacter type III polyketide synthases: a single amino acid substitution reverses their cyclization specificity.

PubMed

Satou, Ryutaro; Miyanaga, Akimasa; Ozawa, Hiroki; Funa, Nobutaka; Katsuyama, Yohei; Miyazono, Ken-ichi; Tanokura, Masaru; Ohnishi, Yasuo; Horinouchi, Sueharu

2013-11-22

Type III polyketide synthases (PKSs) show diverse cyclization specificity. We previously characterized two Azotobacter type III PKSs (ArsB and ArsC) with different cyclization specificity. ArsB and ArsC, which share a high sequence identity (71%), produce alkylresorcinols and alkylpyrones through aldol condensation and lactonization of the same polyketomethylene intermediate, respectively. Here we identified a key amino acid residue for the cyclization specificity of each enzyme by site-directed mutagenesis. Trp-281 of ArsB corresponded to Gly-284 of ArsC in the amino acid sequence alignment. The ArsB W281G mutant synthesized alkylpyrone but not alkylresorcinol. In contrast, the ArsC G284W mutant synthesized alkylresorcinol with a small amount of alkylpyrone. These results indicate that this amino acid residue (Trp-281 of ArsB or Gly-284 of ArsC) should occupy a critical position for the cyclization specificity of each enzyme. We then determined crystal structures of the wild-type and G284W ArsC proteins at resolutions of 1.76 and 1.99 Å, respectively. Comparison of these two ArsC structures indicates that the G284W substitution brings a steric wall to the active site cavity, resulting in a significant reduction of the cavity volume. We postulate that the polyketomethylene intermediate can be folded to a suitable form for aldol condensation only in such a relatively narrow cavity of ArsC G284W (and presumably ArsB). This is the first report on the alteration of cyclization specificity from lactonization to aldol condensation for a type III PKS. The ArsC G284W structure is significant as it is the first reported structure of a microbial resorcinol synthase.

Sub-lethal exposure of cockroaches to boric acid pesticide contributes to increased Bla g 2 excretion.

PubMed

Zhang, Y C; Perzanowski, M S; Chew, G L

2005-07-01

Several epidemiology studies have found an increase in the major cockroach allergen Bla g 2 with reported pesticide use. Our aim was to investigate the effect on the excretion of Bla g 1 and Bla g 2 allergens by cockroaches exposed to sub-lethal doses of the pesticides, boric acid and hydramethylnon gel. German cockroaches in separate colonies were fed either boric acid or hydramethylnon gel at concentrations of 0.2, 0.1 and 0.01% in their water supply over a 2 week period. Ten colonies were exposed to each treatment concentration. Bla g 1 and Bla g 2 in fecal pellets were measured by ELISA. Cockroaches exposed to boric acid excreted fecal pellets with significantly higher concentrations of Bla g 2 (35,400 U/g) than did controls (12,700 U/g) (P = 0.001). Bla g 1 concentrations were not significantly different. There was no difference in either Bla g 1 or Bla g 2 concentrations between cockroaches that ingested hydramethylnon gel and those in the controls colonies. The application of boric acid, a common pesticide, appears to paradoxically increase the production of Bla g 2, a major allergen, by the surviving cockroaches. This may have important implications in avoidance strategies.

Changes in Amino Acid Content of Excised Leaves During Incubation I. The Effect of Water Content of Leaves and Atmospheric Oxygen Level

PubMed Central

Thompson, John F.; Stewart, Cecil R.; Morris, Clayton J.

1966-01-01

Excised leaves were incubated at various water contents to determine the effect of water status on amino acid composition. Considerable proteolysis took place during incubation with a resultant increase in each amino acid in the non-protein fraction. However, serine, proline, γ-aminobutyric acid and methyleysteine sulfoxide were the only amino acids in which there was an accumulation (i.e., net synthesis). Serine showed a small but consistent accumulation lasting for 6 days. Proline showed a greater accumulation but this ceased after 2 days. To learn more about the control of the proline accumulation during wilting, turgid and wilted leaves were incubated under aerobic and anaerobic conditions. The amino acid analyses showed that turgid leaves did not accumulate proline and that proline and methylcysteine sulfoxide accumulation was abolished by anaerobiosis. With other amino acids, relative concentration changes between wilted and non-wilted leaves were less striking than the difference between aerobic and anaerobic conditions. Under anaerobic conditions there was an increase in alanine and a large increase in γ-aminobutyric acid which were not evident in air. Serine, aspartic acid, glutamic acid, and glutamine disappeared more rapidly and glycine disappeared less rapidly under anaerobic than under aerobic conditions. On the basis of these results, several pathways of amino acid degradation were suggested. PMID:16656443

Ameliorative effect of synthetic γ-aminobutyric acid (GABA) on performance traits, antioxidant status and immune response in broiler exposed to cyclic heat stress.

PubMed

Chand, Naila; Muhammad, Sher; Khan, Rifat Ullah; Alhidary, Ibrahim Abdullah; Rehman, Zia Ur

2016-12-01

The aim of this study was to find the effect of synthetic γ-aminobutyric acid (GABA) on the performance, antioxidant status, and immune response in broiler exposed to summer stress. A total of 400-day-old male broiler chickens (Ross 308) was randomly distributed into five treatments (5 replicates). One group served as a control (basal diet only) while the others were supplemented with GABA at the rate of 25 (GABA-25), 50 (GABA 50), 75 (GABA-75), and 100 (GABA-100) mg/kg feed. The experiment was continued for 35 days. Feed intake during the third week was significantly higher (P < 0.05) in GABA-75 and GABA-100, however, it increased significantly (P < 0.05) in GABA-100 during the fourth and fifth week. Overall mean feed intake was significantly (P < 0.05) high in GABA-75 and GABA-100. From the results, we found that body weight improved significantly (P < 0.05) in GABA-50 in week-3. During the fourth, fifth, and overall, body weight increased significantly (P < 0.05) in GABA-100. Significantly, high (P < 0.05) feed conversion ratio (FCR) was found in GABA-100 during the third, fourth, fifth, and on an overall basis. Mean Malondialdehyde (MDA) decreased significantly (P < 0.05) in GABA-100 while Paraoxonase (PON1) and Newcastle disease (ND) titer increased significantly (P < 0.05) in the same group. We concluded that performance traits, antioxidant status, and immune response improved in broiler supplemented 100 mg/kg GABA, exposed to cyclic heat stress.

Enhanced Production of Gamma-Aminobutyric Acid by Optimizing Culture Conditions of Lactobacillus brevis HYE1 Isolated from Kimchi, a Korean Fermented Food.

PubMed

Lim, Hee Seon; Cha, In-Tae; Roh, Seong Woon; Shin, Hae-Hun; Seo, Myung-Ji

2017-03-28

This study evaluated the effects of culture conditions, including carbon and nitrogen sources, L-monosodium glutamate (MSG), and initial pH, on gamma-aminobutyric acid (GABA) production by Lactobacillus brevis HYE1 isolated from kimchi, a Korean traditional fermented food. L. brevis HYE1 was screened by the production analysis of GABA and genetic analysis of the glutamate decarboxylase gene, resulting in 14.64 mM GABA after 48 h of cultivation in MRS medium containing 1% (w/v) MSG. In order to increase GABA production by L. brevis HYE1, the effects of carbon and nitrogen sources on GABA production were preliminarily investigated via one-factor-at-a-time optimization strategy. As the results, 2% maltose and 3% tryptone were determined to produce 17.93 mM GABA in modified MRS medium with 1% (w/v) MSG. In addition, the optimal MSG concentration and initial pH were determined to be 1% and 5.0, respectively, resulting in production of 18.97 mM GABA. Thereafter, response surface methodology (RSM) was applied to determine the optimal conditions of the above four factors. The results indicate that pH was the most significant factor for GABA production. The optimal culture conditions for maximum GABA production were also determined to be 2.14% (w/v) maltose, 4.01% (w/v) tryptone, 2.38% (w/v) MSG, and an initial pH of 4.74. In these conditions, GABA production by L. brevis HYE1 was predicted to be 21.44 mM using the RSM model. The experiment was performed under these optimized conditions, resulting in GABA production of 18.76 mM. These results show that the predicted and experimental values of GABA production are in good agreement.

Effect of γ-aminobutyric acid and nattokinase-enriched fermented beans on the blood pressure of spontaneously hypertensive and normotensive Wistar-Kyoto rats.

PubMed

Suwanmanon, Kanintra; Hsieh, Pao-Chuan

2014-12-01

In this study we have evaluated the changes in arterial blood pressure in spontaneously hypertensive rats (SHR) caused by the short-term intake of Bacillus subtilis B060-fermented beans with significant γ-aminobutyric acid (GABA) and nattokinase activity. After being weaned, 7-week-old male SHR and 7-week-old male Wistar-Kyoto (WKY) rats were randomized into seven groups. Until the 8 th week of life, the rats in each group were given one of the following: Group 1, high dose of GABA and nattokinase in the SHR (SHD); Group 2, medium dose of GABA and nattokinase in the SHR (SMD); Group 3, low dose of GABA and nattokinase in the SHR (SLD); Group 4, negative control in the SHR (SD); Group 5, positive control in the SHR (SM); Group 6, high dose of GABA and nattokinase in the WKY (WHD); and Group 7, negative control in the WKY (WD). Distilled water served as the negative control, and captopril (50 mg/kg), a known ACE inhibitor, served as the positive control. Systolic blood pressure and diastolic blood pressure values were measured weekly from the 8 th week to the 16 th week of life using the tail-cuff method. A definite decrease in systolic and diastolic blood pressure values could be observed in the rats treated with captopril and in the rats that received GABA and nattokinase. The greatest antihypertensive effect was observed when the pharmacological treatment was administered. The effect of the daily intake of fermented beans containing GABA and nattokinase may be helpful in controlling blood pressure levels in hypertensive model animals. The fermentation of beans with B. subtilis B060 may therefore constitute a successful strategy for producing a functional food with antihypertensive activity. Copyright © 2014. Published by Elsevier B.V.

Effects of dietary glutamine and gamma-aminobutyric acid on meat colour, pH, composition, and water-holding characteristic in broilers under cyclic heat stress.

PubMed

Dai, S F; Gao, F; Xu, X L; Zhang, W H; Song, S X; Zhou, G H

2012-01-01

1. An experiment was conducted to evaluate the effects of dietary glutamine (Gln, 0 and 5 g/kg) and gamma-aminobutyric acid (GABA, 0 and 100 mg/kg) on raw breast meat colour, pH, composition and water-holding characteristic of broilers under cyclic heat stress (HS). 2. A total of 360 21-d-old Arbor Acres male chicks were randomly assigned to 5 treatment groups (6 replicates of 12 birds per cage). The positive control (PC) broilers were kept in a thermoneutral chamber (22-24°C) and fed on the basal diet. The other 4 groups were kept in a cyclic HS chamber (30-34°C) for 9 h (from 09:00 to 18:00). 3. A significant increase was observed in breast meat lightness at 28, 35 and 42 d; and pH values at 28, 35 and 42 d; while a significant decrease was observed in breast meat cooking loss (CL) and contents of moisture, crude protein (CP), crude fat (CF) and crude ash (CA) due to HS. 4. The supplementation with 0·5 g Gln/kg decreased lightness at 28, 35 and 42 d; while increasing redness at 28 d, yellowness at 35 d, contents of CP, CF and CA, thawing loss (TL) and drip loss (DL). The addition of 100 mg GABA/kg decreased lightness at 28 and 35 d, pH value at 28, 35 and 42 d, and TL; while increasing redness at 28 d, 35 and 42 d, contents of moisture, CP and CF. 5. The lightness, redness, and pH value; contents of moisture, CP, CF and CA; and TL, DL and CL of breast meat of broilers fed with the mixture of Gln and GABA under cyclic HS were similar to those of the broilers in the PC group. 6. Significant interactions were found between Gln and GABA for yellowness at 28 and 35 d; pH at 28, 35 and 42 d; moisture content, CP content, water-holding capacity and TL. 7. These results demonstrated that dietary Gln and GABA offer a potential nutritional strategy to prevent cyclic HS-related depression in broiler meat chemical composition and quality.

Abscisic Acid–Responsive Guard Cell Metabolomes of Arabidopsis Wild-Type and gpa1 G-Protein Mutants[C][W

PubMed Central

Jin, Xiaofen; Wang, Rui-Sheng; Zhu, Mengmeng; Jeon, Byeong Wook; Albert, Reka; Chen, Sixue; Assmann, Sarah M.

2013-01-01

Individual metabolites have been implicated in abscisic acid (ABA) signaling in guard cells, but a metabolite profile of this specialized cell type is lacking. We used liquid chromatography–multiple reaction monitoring mass spectrometry for targeted analysis of 85 signaling-related metabolites in Arabidopsis thaliana guard cell protoplasts over a time course of ABA treatment. The analysis utilized ∼350 million guard cell protoplasts from ∼30,000 plants of the Arabidopsis Columbia accession (Col) wild type and the heterotrimeric G-protein α subunit mutant, gpa1, which has ABA-hyposensitive stomata. These metabolomes revealed coordinated regulation of signaling metabolites in unrelated biochemical pathways. Metabolites clustered into different temporal modules in Col versus gpa1, with fewer metabolites showing ABA-altered profiles in gpa1. Ca2+-mobilizing agents sphingosine-1-phosphate and cyclic adenosine diphosphate ribose exhibited weaker ABA-stimulated increases in gpa1. Hormone metabolites were responsive to ABA, with generally greater responsiveness in Col than in gpa1. Most hormones also showed different ABA responses in guard cell versus mesophyll cell metabolomes. These findings suggest that ABA functions upstream to regulate other hormones, and are also consistent with G proteins modulating multiple hormonal signaling pathways. In particular, indole-3-acetic acid levels declined after ABA treatment in Col but not gpa1 guard cells. Consistent with this observation, the auxin antagonist α-(phenyl ethyl-2-one)-indole-3-acetic acid enhanced ABA-regulated stomatal movement and restored partial ABA sensitivity to gpa1. PMID:24368793

Noni as an anxiolytic and sedative: a mechanism involving its gamma-aminobutyric acidergic effects.

PubMed

Deng, S; West, B J; Palu, A K; Zhou, B-N; Jensen, C J

2007-08-01

Noni (Morinda citrifolia) is increasing in worldwide popularity as a food or dietary supplement with versatile health benefits. The aim of this study was to investigate the effects of Noni fruit on anxiety symptoms in vitro. To this end, a competitive GABAa receptor-binding assay was developed. Our preliminary study indicates that the methanol crude extract of Noni fruit showed significant affinity to the gamma-aminobutyric acid A (GABAa) inhibitory neurotransmitter receptors, and displayed 75% binding inhibition of the agonist radioligand [3H] muscimol at a concentration of 100 microg/ml. Further experiments demonstrated that the MeOH extract, and its BuOH and H2O partitions, exhibited IC50 values of 22.8, 27.2, and 17.1 microg/ml, respectively, in the GABAa-binding assay. Experimental results with Noni fruit indicate the presence of competitive ligand(s), which may bind to the GABAa receptor as an agonist, and thus induce its anxiolytic and sedative effects. The study provides an in vitro rationale for one of Noni's versatile and traditional uses. In addition, an HPLC fingerprint profile of the methanolic extract of Noni fruit has been established for quality control purpose.

The G Protein-Coupled Bile Acid Receptor, TGR5, Stimulates Gallbladder Filling

PubMed Central

Li, Tingting; Holmstrom, Sam R.; Kir, Serkan; Umetani, Michihisa; Schmidt, Daniel R.

2011-01-01

TGR5 is a G protein-coupled bile acid receptor present in brown adipose tissue and intestine, where its agonism increases energy expenditure and lowers blood glucose. Thus, it is an attractive drug target for treating human metabolic disease. However, TGR5 is also highly expressed in gallbladder, where its functions are less well characterized. Here, we demonstrate that TGR5 stimulates the filling of the gallbladder with bile. Gallbladder volume was increased in wild-type but not Tgr5−/− mice by administration of either the naturally occurring TGR5 agonist, lithocholic acid, or the synthetic TGR5 agonist, INT-777. These effects were independent of fibroblast growth factor 15, an enteric hormone previously shown to stimulate gallbladder filling. Ex vivo analyses using gallbladder tissue showed that TGR5 activation increased cAMP concentrations and caused smooth muscle relaxation in a TGR5-dependent manner. These data reveal a novel, gallbladder-intrinsic mechanism for regulating gallbladder contractility. They further suggest that TGR5 agonists should be assessed for effects on human gallbladder as they are developed for treating metabolic disease. PMID:21454404

Adsorption of Copper Ion using Acrylic Acid-g-Polyaniline in Aqueous Solution

NASA Astrophysics Data System (ADS)

Kamarudin, Sabariah; Mohammad, Masita

2018-04-01

A conductive polymer, polyaniline (PANI) has unique electrical behaviour, stable in the environment, easy synthesis and have wide application in various fields. Modification of PANI in order to improve its adsorption capacity has been done. In this study, the polyaniline-grafted acrylic acid has been prepared and followed by adsorption of copper ion in aqueous solution. Acrylic acid, PANI and acrylic acid-g-polyaniline (Aag-PANI) were characterized by FTIR and SEM to determine its characteristic. The adsorption capacity was investigated to study the removal capacity of Cu ion from aqueous solution. Two parameters were selected which are pH (2, 4 and 6) and initial metal ion concentration (50 mg/L, 100 mg/L and 200 mg/L). The maximum adsorption capacity for PANI and Aag-PANI are 1.7 mg/g and 64.6 mg/g, respectively, at an initial concentration of 100 mg/L. The Langmuir adsorption isotherm model and Freundlich adsorption isotherm model have been used and showed that it is heterolayer adsorption by follows the Freundlich isotherm model.

GABAergic control of food intake in the meat-type chickens.

PubMed

Jonaidi, H; Babapour, V; Denbow, D M

2002-08-01

This study examined the effects of intracerebroventricular injections of gamma-aminobutyric acid (GABA) agonists on short-term food intake in meat-type cockerels. In Experiment 1, birds were injected with various doses of muscimol, a GABA(A) agonist. In Experiment 2, the birds received bicuculline, a GABA(A) antagonist, prior to injection of muscimol. In Experiment 3, the effect of varying doses of baclofen, a GABA(B) agonist, on food intake was determined. The intracerebroventricular injection of muscimol caused a dose-dependent increase in food intake. This effect was significantly attenuated by pretreatment with bicuculline. Food intake was not affected by the intracerebroventricular injection of baclofen. These results suggest that GABA acts within the brain of broilers at a GABA(A), but not GABA(B), receptor to increase voluntary food intake.

Oral administration of γ-aminobutyric acid affects heat production in a hot environment in resting humans.

PubMed

Miyazawa, Taiki; Kawabata, Takashi; Okazaki, Kazunobu; Suzuki, Takashi; Imai, Daiki; Hamamoto, Takeshi; Matsumura, Shinya; Miyagawa, Toshiaki

2012-02-29

Central administration of γ-amino butyric acid (GABA) induces lower body temperature in animals in hot ambient air. However, it is still unknown whether oral GABA administration affects temperature regulation at rest in a hot environment in humans. Therefore, in the present study, we specifically hypothesized that systemic administration of GABA in humans would induce hypothermia in a hot environment and that this response would be observed in association with decreased heat production. Eight male participants drank a 200-ml sports drink with 1 g of GABA (trial G) or without GABA (trial C), then rested for 30 minutes in a sitting position in a hot environment (ambient air temperature 33°C, relative humidity 50%). We found that changes in esophageal temperature from before drinking the sports drink were lower in trial G than in trial C (-0.046 ± 0.079°C vs 0.001 ± 0.063°C; P < 0.05), with lower heat production calculated by oxygen consumption (41 ± 5 W/m2 vs 47 ± 8 W/m2; P < 0.05). In this study, we have demonstrated that a single oral administration of GABA induced a larger decrease in body core temperature compared to a control condition during rest in a hot environment and that this response was concomitant with a decrease in total heat production.

PYRETHROID INSECTICIDES AND THE GAMMA-AMINOBUTYRIC ACID (ALPHA) RECEPTOR COMPLEX: MOTOR ACTIVITY AND THE ACOUSTIC STARTLE RESPONSE IN THE RAT (JOURNAL VERSION)

EPA Science Inventory

Two behavioral tests, locomotor activity and the acoustic startle response (ASR), were utilized to test for dose-addition of cismethrin, a Type I, or deltamethrin, a Type II pyrethroid, with compounds active to the gamma-aminobutryic acid (GABA) receptor complex (picrotoxin, musc...

Quantification of γ-aminobutyric acid in the heads of houseflies (Musca domestica) and diamondback moths (Plutella xylostella (L.)), using capillary electrophoresis with laser-induced fluorescence detection.

PubMed

Shi, Xueyan; Liang, Pei; Song, Dunlun; Yang, Wenling; Gao, Xiwu

2012-02-01

A novel method was developed for quantifying the levels of γ-aminobutyric acid (GABA) in the heads of houseflies (Musca domestica) and diamondback moths (Plutella xylostella (L.)), using capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). The GABA in sample was derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) prior to CE-LIF analysis. In total, 32 mmol/L borate buffer, at pH 9.2 and containing 5.3 mmol/L β-cyclodextrin (β-CD) and 10.4 mmol/L sodium dodecyl sulfate (SDS), was determined to be the optimum CE background electrolyte (BGE) for GABA analysis. The detection limit of GABA was 0.016 μmol/L. The relative standard deviations (RSDs) of the migration time and peak area of GABA were 1.78 and 4.93%, respectively. The average recoveries of 0.97, 3.88, and 5.83 μmol/L of GABA, each added to the head sample of housefly, ranged from 88.9 to 110.5%. This method is simple and applicable to GABA assays of the heads of insects. With this newly developed CE-LIF method, the amounts of GABA in the heads of houseflies (M. domestica) and diamondback moths (P. xylostella (L.)) were measured. The results are relevant to the understandings of some insecticides and insecticide-resistance mechanisms in pests. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Neuroexcitatory Drug Receptors in Mammals and Invertebrates.

DTIC Science & Technology

1986-11-30

1082 . 9. Lawrence, J.J. and Casida, J.E. (1983) Stereospecific action of pyrethroid insecticides on the y-aminobutyric acid receptor-ionophore...1984). Olsen, R.W. and A.M. Snowman. Avermectin B Modulation of GABA Receptor Binding in Rat Brain, J. Neurochem. 44, 1074- 1082 (1985). Lunt, G.G., T

The selective conversion of glutamic acid in amino acid mixtures using glutamate decarboxylase--a means of separating amino acids for synthesizing biobased chemicals.

PubMed

Teng, Yinglai; Scott, Elinor L; Sanders, Johan P M

2014-01-01

Amino acids (AAs) derived from hydrolysis of protein rest streams are interesting feedstocks for the chemical industry due to their functionality. However, separation of AAs is required before they can be used for further applications. Electrodialysis may be applied to separate AAs, but its efficiency is limited when separating AAs with similar isoelectric points. To aid the separation, specific conversion of an AA to a useful product with different charge behavior to the remaining compounds is desired. Here the separation of L-aspartic acid (Asp) and L-glutamic acid (Glu) was studied. L-Glutamate α-decarboxylase (GAD, Type I, EC 4.1.1.15) was applied to specifically convert Glu into γ-aminobutyric acid (GABA). GABA has a different charge behavior from Asp therefore allowing a potential separation by electrodialysis. Competitive inhibition and reduced operational stability caused by Asp could be eliminated by maintaining a sufficiently high concentration of Glu. Immobilization of GAD does not reduce the enzyme's initial activity. However, the operational stability was slightly reduced. An initial study on the reaction operating in a continuous mode was performed using a column reactor packed with immobilized GAD. As the reaction mixture was only passed once through the reactor, the conversion of Glu was lower than expected. To complete the conversion of Glu, the stream containing Asp and unreacted Glu might be recirculated back to the reactor after GABA has been removed. Overall, the reaction by GAD is specific to Glu and can be applied to aid the electrodialysis separation of Asp and Glu. © 2014 American Institute of Chemical Engineers.

Decalcification by ascorbic acid for immuno- and affinohistochemical techniques on the inner ear.

PubMed

Merchán-Pérez, A; Gil-Loyzaga, P; Bartolomé, M V; Remezal, M; Fernández, P; Rodríguez, T

1999-08-01

An ascorbic acid decalcifying solution was applied to immuno- and affinohistochemical studies on the inner ear. Rat inner ears fixed in 4% paraformaldehyde in PBS or in 2% acetic acid in ethanol solutions were adequately decalcified in an ascorbic acid solution, at a temperature of 4 degrees C. The decalcifying solution was prepared with 1% ascorbic acid and 0.84% sodium chloride in distilled water (pH 2.5-2.6). The decalcification time was in a direct relationship to the specimen calcification. In this study, two neuroactive substances (gamma-aminobutyric acid and calcitonin gene-related peptide), neurofilaments, and the galectine endogenous lectin were successfully detected immunohistochemically.

Glucose and amino acid metabolism in rat brain during sustained hypoglycemia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, K.L.; Tyce, G.M.

1983-04-01

The metabolism of glucose in brains during sustained hypoglycemia was studied. (U-/sup 14/C)Glucose (20 microCi) was injected into control rats, and into rats at 2.5 hr after a bolus injection of 2 units of insulin followed by a continuous infusion of 0.2 units/100 g rat/hr. This regimen of insulin injection was found to result in steady-state plasma glucose levels between 2.5 and 3.5 mumol per ml. In the brains of control rats carbon was transferred rapidly from glucose to glutamate, glutamine, gamma-aminobutyric acid and aspartate and this carbon was retained in the amino acids for at least 60 min. Inmore » the brains of hypoglycemic rats, the conversion of carbon from glucose to amino acids was increased in the first 15 min after injection. After 15 min, the specific activity of the amino acids decreased in insulin-treated rats but not in the controls. The concentrations of alanine, glutamate, and gamma-amino-butyric acid decreased, and the concentration of aspartate increased, in the brains of the hypoglycemic rats. The concentration of pyridoxal-5'-phosphate, a cofactor in many of the reactions whereby these amino acids are formed from tricarboxylic acid cycle intermediates, was less in the insulin-treated rats than in the controls. These data provide evidence that glutamate, glutamine, aspartate, and GABA can serve as energy sources in brain during insulin-induced hypoglycemia.« less

Gamma-aminobutyric acid, a potential tumor suppressor for small airway-derived lung adenocarcinoma.

PubMed

Schuller, Hildegard M; Al-Wadei, Hussein A N; Majidi, Mourad

2008-10-01

Pulmonary adenocarcinoma (PAC) is the leading type of lung cancer in smokers and non-smokers that arises in most cases from small airway epithelial cells. PAC has a high mortality due to its aggressive behavior and resistance to cancer therapeutics. We have shown previously that the proliferation of human PAC cells NCI-H322 and immortalized human small airway epithelial cells HPL1D is stimulated by cyclic adenosine monophosphate (cAMP)/protein kinase A-dependent phosphorylation of cyclic adenosine monophosphate response element-binding (CREB) protein and transactivation of the epidermal growth factor receptor and that this pathway is activated by beta-1-adrenoreceptors (beta(1)-ARs) and the non-genomic estrogen receptor beta. Our current in vitro studies with HPL1D and NCI-H322 cells showed that signaling via the gamma-amino butyric acid receptor (GABA(B)R) strongly inhibited base level and isoproterenol-induced cAMP, p-CREB, cyclic adenosine monophosphate response element-luciferase activity and p-extracellular regulated kinase-1 (ERK1)/2 and effectively blocked DNA synthesis and cell migration. The inhibitory effects of gamma-amino butyric acid (GABA) were disinhibited by the GABA(B)R antagonist CGP-35348 or GABA(B)R knockdown. Immunohistochemical investigation of hamster lungs showed significant underexpression of GABA in animals with small airway-derived PACs induced by the nicotine-derived carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These findings suggest that GABA may have tumor suppressor function in small airway epithelia and the PACs derived from them and that downregulation of GABA by NNK may contribute to the development of this cancer in smokers. Our findings suggest that marker-guided treatment with GABA or a GABA(B)R agonist of individuals with downregulated pulmonary GABA may provide a novel targeted approach for the prevention of PAC in smokers.

Experimental Shock Chemistry of Aqueous Amino Acid Solutions and the Cometary Delivery of Prebiotic Compounds

NASA Astrophysics Data System (ADS)

Blank, Jennifer G.; Miller, Gregory H.; Ahrens, Michael J.; Winans, Randall E.

2001-02-01

A series of shock experiments were conducted to assess the feasibility of the delivery of organic compounds to the Earth via cometary impacts. Aqueous solutions containing near-saturation levels of amino acids (lysine, norvaline, aminobutyric acid, proline, and phenylalanine) were sealed inside stainless steel capsules and shocked by ballistic impact with a steel projectile plate accelerated along a 12-m-long gun barrel to velocities of 0.5-1.9 km sec^-1. Pressure-temperature-time histories of the shocked fluids were calculated using 1D hydrodynamical simulations. Maximum conditions experienced by the solutions lasted 0.85-2.7 μs and ranged from 5.1-21 GPa and 412-870 K. Recovered sample capsules were milled open and liquid was extracted. Samples were analyzed using high performance liquid chromatography (HPLC) and mass spectrometry (MS). In all experiments, a large fraction of the amino acids survived. We observed differences in kinetic behavior and the degree of survivability among the amino acids. Aminobutyric acid appeared to be the least reactive, and phenylalanine appeared to be the most reactive of the amino acids. The impact process resulted in the formation of peptide bonds; new compounds included amino acid dimers and cyclic diketopiperazines. In our experiments, and in certain naturally occurring impacts, pressure has a greater influence than temperature in determining reaction pathways. Our results support the hypothesis that significant concentrations of organic material could survive a natural impact process.

Experimental shock chemistry of aqueous amino acid solutions and the cometary delivery of prebiotic compounds.

PubMed

Blank, J G; Miller, G H; Ahrens, M J; Winans, R E

2001-01-01

A series of shock experiments were conducted to assess the feasibility of the delivery of organic compounds to the Earth via cometary impacts. Aqueous solutions containing near-saturation levels of amino acids (lysine, norvaline, aminobutyric acid, proline, and phenylalanine) were sealed inside stainless steel capsules and shocked by ballistic impact with a steel projectile plate accelerated along a 12-m-long gun barrel to velocities of 0.5-1.9 km sec-1. Pressure-temperature-time histories of the shocked fluids were calculated using 1D hydrodynamical simulations. Maximum conditions experienced by the solutions lasted 0.85-2.7 microseconds and ranged from 5.1-21 GPa and 412-870 K. Recovered sample capsules were milled open and liquid was extracted. Samples were analyzed using high performance liquid chromatography (HPLC) and mass spectrometry (MS). In all experiments, a large fraction of the amino acids survived. We observed differences in kinetic behavior and the degree of survivability among the amino acids. Aminobutyric acid appeared to be the least reactive, and phenylalanine appeared to be the most reactive of the amino acids. The impact process resulted in the formation of peptide bonds; new compounds included amino acid dimers and cyclic diketopiperazines. In our experiments, and in certain naturally occurring impacts, pressure has a greater influence than temperature in determining reaction pathways. Our results support the hypothesis that significant concentrations of organic material could survive a natural impact process.

Type 2 Diabetes and Uric Acid Nephrolithiasis

NASA Astrophysics Data System (ADS)

Maalouf, Naim M.

2008-09-01

Type 2 diabetes is associated with an increased propensity for uric acid nephrolithiasis. In individuals with diabetes, this increased risk is due to a lower urine pH that results from obesity, dietary factors, and impaired renal ammoniagenesis. The epidemiology and pathogenesis of uric acid stone disease in patients with diabetes are hereby reviewed, and potential molecular mechanisms are proposed.

Structural, signalling and regulatory properties of the group I metabotropic glutamate receptors: prototypic family C G-protein-coupled receptors.

PubMed Central

Hermans, E; Challiss, R A

2001-01-01

In 1991 a new type of G-protein-coupled receptor (GPCR) was cloned, the type 1a metabotropic glutamate (mGlu) receptor, which, despite possessing the defining seven-transmembrane topology of the GPCR superfamily, bore little resemblance to the growing number of other cloned GPCRs. Subsequent studies have shown that there are eight mammalian mGlu receptors that, together with the calcium-sensing receptor, the GABA(B) receptor (where GABA is gamma-aminobutyric acid) and a subset of pheromone, olfactory and taste receptors, make up GPCR family C. Currently available data suggest that family C GPCRs share a number of structural, biochemical and regulatory characteristics, which differ markedly from those of the other GPCR families, most notably the rhodopsin/family A GPCRs that have been most widely studied to date. This review will focus on the group I mGlu receptors (mGlu1 and mGlu5). This subgroup of receptors is widely and differentially expressed in neuronal and glial cells within the brain, and receptor activation has been implicated in the control of an array of key signalling events, including roles in the adaptative changes needed for long-term depression or potentiation of neuronal synaptic connectivity. In addition to playing critical physiological roles within the brain, the mGlu receptors are also currently the focus of considerable attention because of their potential as drug targets for the treatment of a variety of neurological and psychiatric disorders. PMID:11672421

Increased Cortical Gamma-Aminobutyric Acid Precedes Incomplete Extinction of Conditioned Fear and Increased Hippocampal Excitatory Tone in a Mouse Model of Mild Traumatic Brain Injury.

PubMed

Schneider, Brandy L; Ghoddoussi, Farhad; Charlton, Jennifer L; Kohler, Robert J; Galloway, Matthew P; Perrine, Shane A; Conti, Alana C

2016-09-01

Mild traumatic brain injury (mTBI) contributes to development of affective disorders, including post-traumatic stress disorder (PTSD). Psychiatric symptoms typically emerge in a tardive fashion post-TBI, with negative effects on recovery. Patients with PTSD, as well as rodent models of PTSD, demonstrate structural and functional changes in brain regions mediating fear learning, including prefrontal cortex (PFC), amygdala (AMYG), and hippocampus (HC). These changes may reflect loss of top-down control by which PFC normally exhibits inhibitory influence over AMYG reactivity to fearful stimuli, with HC contribution. Considering the susceptibility of these regions to injury, we examined fear conditioning (FC) in the delayed post-injury period, using a mouse model of mTBI. Mice with mTBI displayed enhanced acquisition and delayed extinction of FC. Using proton magnetic resonance spectroscopy ex vivo, we examined PFC, AMYG, and HC levels of gamma-aminobutyric acid (GABA) and glutamate as surrogate measures of inhibitory and excitatory neurotransmission, respectively. Eight days post-injury, GABA was increased in PFC, with no significant changes in AMYG. In animals receiving FC and mTBI, glutamate trended toward an increase and the GABA/glutamate ratio decreased in ventral HC at 25 days post-injury, whereas GABA decreased and GABA/glutamate decreased in dorsal HC. These neurochemical changes are consistent with early TBI-induced PFC hypoactivation facilitating the fear learning circuit and exacerbating behavioral fear responses. The latent emergence of overall increased excitatory tone in the HC, despite distinct plasticity in dorsal and ventral HC fields, may be associated with disordered memory function, manifested as incomplete extinction and enhanced FC recall.

Differential Ubiquitin Binding by the Acidic Loops of Ube2g1 and Ube2r1 Enzymes Distinguishes Their Lys-48-ubiquitylation Activities*

PubMed Central

Choi, Yun-Seok; Lee, Yun-Ju; Lee, Seo-Yeon; Shi, Lei; Ha, Jung-Hye; Cheong, Hae-Kap; Cheong, Chaejoon; Cohen, Robert E.; Ryu, Kyoung-Seok

2015-01-01

The ubiquitin E2 enzymes, Ube2g1 and Ube2r1, are able to synthesize Lys-48-linked polyubiquitins without an E3 ligase but how that is accomplished has been unclear. Although both E2s contain essential acidic loops, only Ube2r1 requires an additional C-terminal extension (184–196) for efficient Lys-48-ubiquitylation activity. The presence of Tyr-102 and Tyr-104 in the Ube2g1 acidic loop enhanced both ubiquitin binding and Lys-48-ubiquitylation and distinguished Ube2g1 from the otherwise similar truncated Ube2r11–183 (Ube2r1C). Replacement of Gln-105–Ser-106–Gly-107 in the acidic loop of Ube2r1C (Ube2r1CYGY) by the corresponding residues from Ube2g1 (Tyr-102–Gly-103–Tyr-104) increased Lys-48-ubiquitylation activity and ubiquitin binding. Two E2∼UB thioester mimics (oxyester and disulfide) were prepared to characterize the ubiquitin binding activity of the acidic loop. The oxyester but not the disulfide derivative was found to be a functional equivalent of the E2∼UB thioester. The ubiquitin moiety of the Ube2r1CC93S-[15N]UBK48R oxyester displayed two-state conformational exchange, whereas the Ube2r1CC93S/YGY-[15N]UBK48R oxyester showed predominantly one state. Together with NMR studies that compared UBK48R oxyesters of the wild-type and the acidic loop mutant (Y102G/Y104G) forms of Ube2g1, in vitro ubiquitylation assays with various mutation forms of the E2s revealed how the intramolecular interaction between the acidic loop and the attached donor ubiquitin regulates Lys-48-ubiquitylation activity. PMID:25471371

Enhanced Bio-hydrogen Production from Protein Wastewater by Altering Protein Structure and Amino Acids Acidification Type

PubMed Central

Xiao, Naidong; Chen, Yinguang; Chen, Aihui; Feng, Leiyu

2014-01-01

Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type via pH control was investigated. The hydrogen production reached 205.2 mL/g-protein when protein wastewater was pretreated at pH 12 and then fermented at pH 10. The mechanism studies showed that pH 12 pretreatment significantly enhanced protein bio-hydrolysis during the subsequent fermentation stage as it caused the unfolding of protein, damaged the protein hydrogen bonding networks, and destroyed the disulfide bridges, which increased the susceptibility of protein to protease. Moreover, pH 10 fermentation produced more acetic but less propionic acid during the anaerobic fermentation of amino acids, which was consistent with the theory of fermentation type affecting hydrogen production. Further analyses of the critical enzymes, genes, and microorganisms indicated that the activity and abundance of hydrogen producing bacteria in the pH 10 fermentation reactor were greater than those in the control. PMID:24495932

Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type.

PubMed

Xiao, Naidong; Chen, Yinguang; Chen, Aihui; Feng, Leiyu

2014-02-05

Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type via pH control was investigated. The hydrogen production reached 205.2 mL/g-protein when protein wastewater was pretreated at pH 12 and then fermented at pH 10. The mechanism studies showed that pH 12 pretreatment significantly enhanced protein bio-hydrolysis during the subsequent fermentation stage as it caused the unfolding of protein, damaged the protein hydrogen bonding networks, and destroyed the disulfide bridges, which increased the susceptibility of protein to protease. Moreover, pH 10 fermentation produced more acetic but less propionic acid during the anaerobic fermentation of amino acids, which was consistent with the theory of fermentation type affecting hydrogen production. Further analyses of the critical enzymes, genes, and microorganisms indicated that the activity and abundance of hydrogen producing bacteria in the pH 10 fermentation reactor were greater than those in the control.

Enhanced Bio-hydrogen Production from Protein Wastewater by Altering Protein Structure and Amino Acids Acidification Type

NASA Astrophysics Data System (ADS)

Xiao, Naidong; Chen, Yinguang; Chen, Aihui; Feng, Leiyu

2014-02-01

Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type via pH control was investigated. The hydrogen production reached 205.2 mL/g-protein when protein wastewater was pretreated at pH 12 and then fermented at pH 10. The mechanism studies showed that pH 12 pretreatment significantly enhanced protein bio-hydrolysis during the subsequent fermentation stage as it caused the unfolding of protein, damaged the protein hydrogen bonding networks, and destroyed the disulfide bridges, which increased the susceptibility of protein to protease. Moreover, pH 10 fermentation produced more acetic but less propionic acid during the anaerobic fermentation of amino acids, which was consistent with the theory of fermentation type affecting hydrogen production. Further analyses of the critical enzymes, genes, and microorganisms indicated that the activity and abundance of hydrogen producing bacteria in the pH 10 fermentation reactor were greater than those in the control.

Asiatic acid uncouples respiration in isolated mouse liver mitochondria and induces HepG2 cells death.

PubMed

Lu, Yapeng; Liu, Siyuan; Wang, Ying; Wang, Dang; Gao, Jing; Zhu, Li

2016-09-05

Asiatic acid, one of the triterpenoid components isolated from Centella asiatica, has received increasing attention due to a wide variety of biological activities. To date, little is known about its mechanisms of action. Here we examined the cytotoxic effect of asiatic acid on HepG2 cells and elucidated some of the underlying mechanisms. Asiatic acid induced rapid cell death, as well as mitochondrial membrane potential (MMP) dissipation, ATP depletion and cytochrome c release from mitochondria to the cytosol in HepG2 cells. In mitochondria isolated from mouse liver, asiatic acid treatment significantly stimulated the succinate-supported state 4 respiration rate, dissipated the MMP, increased Ca(2+) release from Ca(2+)-loaded mitochondria, decreased ATP content and promoted cytochrome c release, indicating the uncoupling effect of asiatic acid. Hydrogen peroxide (H2O2) produced by succinate-supported mitochondrial respiration was also significantly inhibited by asiatic acid. In addition, asiatic acid inhibited Ca(2+)-induced mitochondrial swelling but did not induce mitochondrial swelling in hyposmotic potassium acetate medium which suggested that asiatic acid may not act as a protonophoric uncoupler. Inhibition of uncoupling proteins (UCPs) or blockade of adenine nucleotide transporter (ANT) attenuated the effect of asiatic acid on MMP dissipation, Ca(2+) release, mitochondrial respiration and HepG2 cell death. When combined inhibition of UCPs and ANT, asiatic acid-mediated uncoupling effect was noticeably alleviated. These results suggested that both UCPs and ANT partially contribute to the uncoupling properties of asiatic acid. In conclusion, asiatic acid is a novel mitochondrial uncoupler and this property is potentially involved in its toxicity on HepG2 cells. Copyright © 2016 Elsevier B.V. All rights reserved.

Bl-1020, a new γ-aminobutyric acid-enhanced antipsychotic: results of 6-week, randomized, double-blind, controlled, efficacy and safety study.

PubMed

Geffen, Yona; Keefe, Richard; Rabinowitz, Jonathan; Anand, Ravi; Davidson, Michael

2012-09-01

BL-1020 is a γ-aminobutyric acid (GABA)-enhanced antipsychotic that combines dopamine antagonism with GABA agonist activity. On the basis of animal models, we tested the hypotheses that BL-1020 would be effective in ameliorating both psychotic symptoms and cognitive impairments, with a favorable safety profile in acutely ill schizophrenia patients. 363 hospital-based psychiatric patients in India, Romania, and United States aged 18 to 65 years and meeting criteria for DSM-IV-TR diagnosis of chronic schizophrenia were randomized double-blind to receive BL-1020 10 mg/d, BL-1020 20-30 mg/d, placebo, or risperidone (2-8 mg/d) for 6 weeks. The main outcome measures were the positive and negative syndrome scale (PANSS), brief assessment of cognition in schizophrenia, readiness for discharge questionnaire, clinical global impressions scale (CGI) , and extrapyramidal symptom rating scale. The study ran from July 2008 to June 2009. BL-1020 20-30 mg was significantly better than placebo on PANSS (P = .02) and CGI (P < .001) measurements, with no significant differences noted between BL-1020 20-30 mg and risperidone. There were no significant differences in the maximum change on extrapyramidal symptom rating scale between risperidone and BL-1020 20-30 mg, and both were significantly worse (P < .001) than placebo. BL-1020 20-30 mg was associated with significantly greater improvements on cognitive functioning as measured by the brief assessment of cognition in schizophrenia composite score when compared to placebo (effect size = 0.50, P = .009), risperidone (effect size = 0.43, P = .019), and BL-1020 10 mg (effect size = 0.42, P = .013) after 6 weeks. BL-1020 appears to be an effective antipsychotic with possible procognitive effects that will need to be further tested for short- and long-term effects. A further randomized controlled trial using the U.S. Food and Drug Administration-recommended Measurement and Treatment Research to Improve Cognition in Schizophrenia cognitive

Simultaneous observation of glutamate, gamma-aminobutyric acid, and glutamine in human brain at 4.7 T using localized two-dimensional constant-time correlation spectroscopy.

PubMed

Watanabe, H; Takaya, N; Mitsumori, F

2008-06-01

Localized two-dimensional constant-time correlation spectroscopy (CT-COSY) was used to resolve glutamate (Glu), gamma-aminobutyric acid (GABA), and glutamine (Gln) in the human brain at 4.7 T. In this method, three-dimensional localization was achieved using three radio frequency pulses of the CT-COSY module for slice selection. As this sequence could decouple JHH along the F1 direction, peak resolution of metabolites was improved even on a magnitude-mode display. In experiments on a phantom containing N-acetylaspartate, creatine, Glu, Gln, and GABA with a constant time delay (Tct) of 110 ms, cross peaks of Glu, Gln, and GABA were obtained on a spectrum processed with standard sine-bell windows, which emphasize sine-dependent signals along the t2 direction. In contrast, diagonal peaks of Glu C4H at 2.35 ppm, GABA C2H at 2.28 ppm, and Gln C4H at 2.44 ppm were resolved on a spectrum processed with Gaussian windows, which emphasize cosine-dependent signals along t2. Human brain spectra were obtained from a 27 mL voxel within the parieto-occipital region using a volume transverse electromagnetic (TEM) coil for both transmission and reception. Tct was 110 ms; the total scan time was 30 min. Diagonal peaks of Glu C4H, GABA C2H, and Gln C4H were also resolved on the spectrum processed with Gaussian windows. These results show that the localized two-dimensional CT-COSY method featuring 1H decoupling along the F1 direction could resolve Glu, GABA, and Gln signals in the human brain. Copyright (c) 2008 John Wiley & Sons, Ltd.

Boric acid solution concentration influencing p-type emitter formation in n-type crystalline Si solar cells

NASA Astrophysics Data System (ADS)

Singha, Bandana; Singh Solanki, Chetan

2016-09-01

Boric acid (BA) is a spin on dopant (BSoD) source which is used to form p+ emitters in n-type c-Si solar cells. High purity boric acid powder (99.99% pure) when mixed with deionized (DI) water can result in high quality p-type emitter with less amount of surface defects. In this work, we have used different concentrations of boric acid solution concentrations to fabricate p-type emitters with sheet resistance values < 90 Ω/□. The corresponding junction depths for the same are less than 500 nm as measured by SIMS analysis. Boron rich layer (BRL), which is considered as detrimental in emitter performance is found to be minimal for BA solution concentration less than 2% and hence useful for p-type emitter formation.

Some distinguishable properties between acid-stable and neutral types of alpha-amylases from acid-producing koji.

PubMed

Suganuma, Toshihiko; Fujita, Kiyotaka; Kitahara, Kanefumi

2007-11-01

The highly humid climate of Japan facilitates the growth of various molds. Among these molds, Aspergillus oryzae is the most important and popular in Japan, and has been used as yellow-koji in producing many traditional fermented beverages and foods, such as Japanese sake, and soy sauce. Taka-amylase A (TAA), a major enzyme produced by the mold, is well known worldwide to be a leading enzyme for industrial utilization and academic study, since many extensive studies have been carried out with TAA. In southern Kyushu, the other koji's of citric acid-producing molds have often been used, such as in the production of a traditional distilled liquor of shochu. The koji molds black-koji and white-koji produce two types of alpha-amylase, namely, acid-stable (AA) and common neutral (NA). The latter enzyme is enzymatically and genetically similar to TAA. In this review, we investigate AA from three molds, Aspergillus niger, A. kawachii and A. awamori, and the yeast Cryptococcus sp. regarding the distinguishable properties between AA and NA. (i) The N-terminus amino acid sequences of AA determined by molecular cloning started with the sequence of L-S-A-, whereas those of NA started with A-T-P-. (ii) Most of the full sequences of AA were composed of, besides a core catalytic domain, an extra domain of a hinge region and a carbohydrate binding domain, which could be responsible for raw-starch-digestibility. The AA from A. niger has no exceptionally extra domain, similarly to NA. (iii) Simple methods for distinguishing AA from NA using CNP-alpha-G3 and G5 as substrates were developed by our group. (iv) The number of subsite in AA on the basis of its cleavage pattern of maltooligosaccharides was estimated to be five, which differs from that of TAA, 7-9. AA has many advantages in industrial applications, such as its acid-stability, thermostability, and raw-starch digesting properties.

Alteration of Transcripts of Stress-Protective Genes and Transcriptional Factors by γ-Aminobutyric Acid (GABA) Associated with Improved Heat and Drought Tolerance in Creeping Bentgrass (Agrostis stolonifera).

PubMed

Li, Zhou; Peng, Yan; Huang, Bingru

2018-05-31

Gamma-aminobutyric acid (GABA) may play a positive role in regulating plant tolerance to drought or heat stress. The objectives of this study were to investigate the physiological effects of GABA on tolerance of creeping bentgrass ( Agrostis stolonifera ) to heat and drought stress and to determine whether enhanced heat and drought tolerance due to GABA treatment was associated with the up-regulation of selected genes and transcriptional factors involved in stress protection. Creeping bentgrass (cultivar "Penncross") plants were treated with 0.5 mM GABA or water (untreated control) as a foliar spray and were subsequently exposed to heat stress (35/30 °C, day/night), drought stress by withholding irrigation, or non-stress conditions in controlled-environment growth chambers. Exogenous application of GABA significantly improved plant tolerance to heat and drought stress, as reflected by increased leaf water content, cell membrane stability, and chlorophyll content. The analysis of gene transcript level revealed that exogenous GABA up-regulated the expression of ABF3 , POD , APX , HSP90 , DHN3 , and MT1 during heat stress and the expression of CDPK26 , MAPK1 , ABF3 , WRKY75 , MYB13 , HSP70 , MT1 , 14-3-3 , and genes ( SOD , CAT , POD , APX , MDHAR , DHAR , and GR ) encoding antioxidant enzymes during drought stress. The up-regulation of the aforementioned stress-protective genes and transcriptional factors could contribute to improved heat and drought tolerance in creeping bentgrass.

WELLTON GOVERNMENT CAMP, PERMANENT GARAGE TYPE 1G. PLAN, ELEVATIONS, AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

WELLTON GOVERNMENT CAMP, PERMANENT GARAGE TYPE 1-G. PLAN, ELEVATIONS, AND SECTIONS. Drawing 50-308-4552, dated October 25, 1949. U.S. Department of the Interior, Bureau of Reclamation, Yuma, Arizona - Wellton-Mohawk Irrigation System, Permanent Garage Type 1-G, 30601 Wellton-Mohawk Drive, Wellton, Yuma County, AZ

WELLTON GOVERNMENT CAMP, PERMANENT GARAGE TYPE 2G. PLAN, ELEVATIONS, AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

WELLTON GOVERNMENT CAMP, PERMANENT GARAGE TYPE 2-G. PLAN, ELEVATIONS, AND SECTIONS. Drawing 50-308-4553, dated October 21, 1949. U.S. Department of the Interior, Bureau of Reclamation, Yuma, Arizona - Wellton-Mohawk Irrigation System, Permanent Garage Type 2-G, 30611 and 30621 Wellton-Mohawk Drive, Wellton, Yuma County, AZ

Frontal Glutamate and γ-Aminobutyric Acid Levels and Their Associations With Mismatch Negativity and Digit Sequencing Task Performance in Schizophrenia.

PubMed

Rowland, Laura M; Summerfelt, Ann; Wijtenburg, S Andrea; Du, Xiaoming; Chiappelli, Joshua J; Krishna, Nithin; West, Jeffrey; Muellerklein, Florian; Kochunov, Peter; Hong, L Elliot

2016-02-01

Auditory mismatch negativity (MMN) is a biomarker for schizophrenia thought to reflect glutamatergic N-methyl-d-aspartate receptor function and excitatory-inhibitory neurotransmission balance. However, the association of glutamate level with MMN has not been directly examined in patients with schizophrenia, to our knowledge. To investigate the contributions of glutamate and γ-aminobutyric acid (GABA) to MMN and digit sequencing task (DST) performance, an assessment of verbal working memory, in schizophrenia. Fifty-three control participants from the community and 45 persons with schizophrenia from outpatient clinics completed an electroencephalographic session for MMN, magnetic resonance spectroscopy for glutamate and GABA, and a DST. The study dates were July 2011 to May 2014, and the dates of our analysis were May 2014 to August 2015. Glutamate, GABA, the ratio of glutamine to glutamate, MMN amplitude, and DST. Structural equation modeling was used to test the effects of neurochemistry and MMN amplitude on DST performance. The 45 persons with schizophrenia were a mean (SD) of 37.7 (12.8) years and the control participants were 37.1 (13.1) years. The schizophrenia group had a mean (SD) of 14.7 (12.1) years of illness. Mismatch negativity amplitude (F = 4.39, P = .04) and glutamate (F = 9.69, P = .002) were reduced in the schizophrenia group. Smaller MMN amplitude was significantly associated with lower GABA level (P = .008), lower glutamate level (P = .05), and higher ratio of glutamine to glutamate (P = .003). Reduced MMN amplitude was linked to poor verbal working memory in schizophrenia (P = .002). Modeling revealed that a proxy of glutamatergic function, indexed by the ratio of glutamine to glutamate, influenced a path from the ratio of glutamine to glutamate to MMN to verbal working memory (P = .38 [root-mean-square error of approximation, P < .001] by χ2 test), supporting the contention that MMN serves as an

Frontal Glutamate and γ-Aminobutyric Acid Levels and Their Associations With Mismatch Negativity and Digit Sequencing Task Performance in Schizophrenia

PubMed Central

Rowland, Laura M.; Summerfelt, Ann; Wijtenburg, S. Andrea; Du, Xiaoming; Chiappelli, Joshua J.; Krishna, Nithin; West, Jeffrey; Muellerklein, Florian; Kochunov, Peter; Hong, L. Elliot

2016-01-01

IMPORTANCE Auditory mismatch negativity (MMN) is a biomarker for schizophrenia thought to reflect glutamatergic N-methyl-d-aspartate receptor function and excitatory-inhibitory neurotransmission balance. However, the association of glutamate level with MMN has not been directly examined in patients with schizophrenia, to our knowledge. OBJECTIVE To investigate the contributions of glutamate and γ-aminobutyric acid (GABA) to MMN and digit sequencing task (DST) performance, an assessment of verbal working memory, in schizophrenia. DESIGN, SETTING, AND PARTICIPANTS Fifty-three control participants from the community and 45 persons with schizophrenia from outpatient clinics completed an electroencephalographic session for MMN, magnetic resonance spectroscopy for glutamate and GABA, and a DST. The study dates were July 2011 to May 2014, and the dates of our analysis were May 2014 to August 2015. MAIN OUTCOMES AND MEASURES Glutamate, GABA, the ratio of glutamine to glutamate, MMN amplitude, and DST. Structural equation modeling was used to test the effects of neurochemistry and MMN amplitude on DST performance. RESULTS The 45 persons with schizophrenia were a mean (SD) of 37.7 (12.8) years and the control participants were 37.1 (13.1) years. The schizophrenia group had a mean (SD) of 14.7 (12.1) years of illness. Mismatch negativity amplitude (F = 4.39, P = .04) and glutamate (F = 9.69, P = .002) were reduced in the schizophrenia group. Smaller MMN amplitude was significantly associated with lower GABA level (P = .008), lower glutamate level (P = .05), and higher ratio of glutamine to glutamate (P = .003). Reduced MMN amplitude was linked to poor verbal working memory in schizophrenia (P = .002). Modeling revealed that a proxy of glutamatergic function, indexed by the ratio of glutamine to glutamate, influenced a path from the ratio of glutamine to glutamate to MMN to verbal working memory (P = .38 [root-mean-square error of approximation, P < .001] by χ2 test

CaLecRK-S.5, a pepper L-type lectin receptor kinase gene, confers broad-spectrum resistance by activating priming

PubMed Central

Woo, Joo Yong; Jeong, Kwang Ju; Kim, Young Jin; Paek, Kyung-Hee

2016-01-01

In Arabidopsis, several L-type lectin receptor kinases (LecRKs) have been identified as putative immune receptors. However, to date, there have been few analyses of LecRKs in crop plants. Virus-induced gene silencing of CaLecRK-S.5 verified the role of CaLecRK-S.5 in broad-spectrum resistance. Compared with control plants, CaLecRK-S.5-silenced plants showed reduced hypersensitive response, reactive oxygen species burst, secondary metabolite production, mitogen-activated protein kinase activation, and defense-related gene expression in response to Tobacco mosaic virus pathotype P0 (TMV-P0) infection. Suppression of CaLecRK-S.5 expression significantly enhanced the susceptibility to Pepper mild mottle virus pathotype P1,2,3, Xanthomonas campestris pv. vesicatoria, Phytophthora capsici, as well as TMV-P0. Additionally, β-aminobutyric acid treatment and a systemic acquired resistance assay revealed that CaLecRK-S.5 is involved in priming of plant immunity. Pre-treatment with β-aminobutyric acid before viral infection restored the reduced disease resistance phenotypes shown in CaLecRK-S.5-silenced plants. Systemic acquired resistance was also abolished in CaLecRK-S.5-silenced plants. Finally, RNA sequencing analysis indicated that CaLecRK-S.5 positively regulates plant immunity at the transcriptional level. Altogether, these results suggest that CaLecRK-S.5-mediated broad-spectrum resistance is associated with the regulation of priming. PMID:27647723

Brain Targeted Intranasal Zaleplon Nano-emulsion: In-Vitro Characterization and Assessment of Gamma Aminobutyric Acid Levels in rabbits' Brain and Plasma at low and high Doses.

PubMed

Abd-Elrasheed, Eman; El-Helaly, Sara Nageeb; El-Ashmoony, Manal M; Salah, Salwa

2017-11-30

Zaleplon is a pyrazolopyrimidin derivative hypnotic drug indicated for the short-term management of insomnia. Zaleplon belongs to Class II drugs, according to the biopharmaceutical classification system (BCS), showing poor solubility and high permeability. It undergoes extensive first-pass hepatic metabolism after oral absorption, with only 30% of Zaleplon being systemically available. It is available in tablet form which is unable to overcome the previous problems. The aim of this study is to enhance solubility and bioavailability via utilizing nanotechnology in the formulation of intranasal Zaleplon nano-emulsion (ZP-NE) to bypass the barriers and deliver an effective therapy to the brain. Screening studies were carried out wherein the solubility of zaleplon in various oils, surfactants(S) and co-surfactants(CoS) were estimated. Pseudo-ternary phase diagrams were constructed and various nano-emulsion formulations were prepared. These formulations were subjected to thermodynamic stability, in-vitro characterization, histopathological studies and assessment of the gamma aminobutyric acid (GABA) level in plasma and brain in rabbits compared to the market product (Sleep aid®). Stable NEs were successfully developed with a particle size range of 44.57±3.351 to 136.90±1.62 nm. A NE composed of 10% Miglyol® 812, 40%Cremophor® RH40 40%Transcutol® HP and 10% water successfully enhanced the bioavailability and brain targeting in the rabbits, showing a three to four folds increase than the marketed product. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

G-rich, a Drosophila selenoprotein, is a Golgi-resident type III membrane protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chang Lan; Shim, Myoung Sup; Chung, Jiyeol

2006-10-06

G-rich is a Drosophila melanogaster selenoprotein, which is a homologue of human and mouse SelK. Subcellular localization analysis using GFP-tagged G-rich showed that G-rich was localized in the Golgi apparatus. The fusion protein was co-localized with the Golgi marker proteins but not with an endoplasmic reticulum (ER) marker protein in Drosophila SL2 cells. Bioinformatic analysis of G-rich suggests that this protein is either type II or type III transmembrane protein. To determine the type of transmembrane protein experimentally, GFP-G-rich in which GFP was tagged at the N-terminus of G-rich, or G-rich-GFP in which GFP was tagged at the C-terminus ofmore » G-rich, were expressed in SL2 cells. The tagged proteins were then digested with trypsin, and analyzed by Western blot analysis. The results showed that the C-terminus of the G-rich protein was exposed to the cytoplasm indicating it is a type III microsomal membrane protein. G-rich is First selenoprotein identified in the Golgi apparatus.« less

Glutamic acid decarboxylase isoform distribution in transgenic mouse septum: an anti-GFP immunofluorescence study.

PubMed

Verimli, Ural; Sehirli, Umit S

2016-09-01

The septum is a basal forebrain region located between the lateral ventricles in rodents. It consists of lateral and medial divisions. Medial septal projections regulate hippocampal theta rhythm whereas lateral septal projections are involved in processes such as affective functions, memory formation, and behavioral responses. Gamma-aminobutyric acidergic neurons of the septal region possess the 65 and 67 isoforms of the enzyme glutamic acid decarboxylase. Although data on the glutamic acid decarboxylase isoform distribution in the septal region generally appears to indicate glutamic acid decarboxylase 67 dominance, different studies have given inconsistent results in this regard. The aim of this study was therefore to obtain information on the distributions of both of these glutamic acid decarboxylase isoforms in the septal region in transgenic mice. Two animal groups of glutamic acid decarboxylase-green fluorescent protein knock-in transgenic mice were utilized in the experiment. Brain sections from the region were taken for anti-green fluorescent protein immunohistochemistry in order to obtain estimated quantitative data on the number of gamma-aminobutyric acidergic neurons. Following the immunohistochemical procedures, the mean numbers of labeled cells in the lateral and medial septal nuclei were obtained for the two isoform groups. Statistical analysis yielded significant results which indicated that the 65 isoform of glutamic acid decarboxylase predominates in both lateral and medial septal nuclei (unpaired two-tailed t-test p < 0.0001 for LS, p < 0.01 for MS). This study is the first to reveal the dominance of glutamic acid decarboxylase isoform 65 in the septal region in glutamic acid decarboxylase-green fluorescent protein transgenic mice.

The Pseudorabies Virus Glycoprotein gE/gI Complex Suppresses Type I Interferon Production by Plasmacytoid Dendritic Cells

PubMed Central

Lamote, Jochen A. S.; Kestens, Manon; Van Waesberghe, Cliff; Delva, Jonas; De Pelsmaeker, Steffi; Devriendt, Bert

2017-01-01

ABSTRACT Plasmacytoid dendritic cells (pDC) play a central role in the antiviral immune response, both in the innate response and in shaping the adaptive response, mainly because of their ability to produce massive amounts of type I interferon (TI-IFN). Here, we report that cells infected with the live attenuated Bartha vaccine strain of porcine alphaherpesvirus pseudorabies virus (PRV) trigger a dramatically increased TI-IFN response by porcine primary pDC compared to cells infected with wild-type PRV strains (Becker and Kaplan). Since Bartha is one of the relatively few examples of a highly successful alphaherpesvirus vaccine, identification of factors that may contribute to its efficacy may provide insights for the rational design of other alphaherpesvirus vaccines. The Bartha vaccine genome displays several mutations compared to the genome of wild-type PRV strains, including a large deletion in the unique short (US) region, encompassing the glycoprotein E (gE), gI, US9, and US2 genes. Using recombinant PRV Becker strains harboring the entire Bartha US deletion or single mutations in the four affected US genes, we demonstrate that the absence of the viral gE/gI complex contributes to the observed increased IFN-α response. Furthermore, we show that the absence of gE leads to an enhanced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in pDC, which correlates with a higher TI-IFN production by pDC. In conclusion, the PRV Bartha vaccine strain triggers strongly increased TI-IFN production by porcine pDC. Our data further indicate that the gE/gI glycoprotein complex suppresses TI-IFN production by pDC, which represents the first alphaherpesvirus factor that suppresses pDC activity. IMPORTANCE Several alphaherpesviruses, including herpes simpex virus, still lack effective vaccines. However, the highly successful Bartha vaccine has contributed substantially to eradication of the porcine alphaherpesvirus pseudorabies virus (PRV) in several countries

The Pseudorabies Virus Glycoprotein gE/gI Complex Suppresses Type I Interferon Production by Plasmacytoid Dendritic Cells.

PubMed

Lamote, Jochen A S; Kestens, Manon; Van Waesberghe, Cliff; Delva, Jonas; De Pelsmaeker, Steffi; Devriendt, Bert; Favoreel, Herman W

2017-04-01

Plasmacytoid dendritic cells (pDC) play a central role in the antiviral immune response, both in the innate response and in shaping the adaptive response, mainly because of their ability to produce massive amounts of type I interferon (TI-IFN). Here, we report that cells infected with the live attenuated Bartha vaccine strain of porcine alphaherpesvirus pseudorabies virus (PRV) trigger a dramatically increased TI-IFN response by porcine primary pDC compared to cells infected with wild-type PRV strains (Becker and Kaplan). Since Bartha is one of the relatively few examples of a highly successful alphaherpesvirus vaccine, identification of factors that may contribute to its efficacy may provide insights for the rational design of other alphaherpesvirus vaccines. The Bartha vaccine genome displays several mutations compared to the genome of wild-type PRV strains, including a large deletion in the unique short (US) region, encompassing the glycoprotein E (gE), gI, US9, and US2 genes. Using recombinant PRV Becker strains harboring the entire Bartha US deletion or single mutations in the four affected US genes, we demonstrate that the absence of the viral gE/gI complex contributes to the observed increased IFN-α response. Furthermore, we show that the absence of gE leads to an enhanced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in pDC, which correlates with a higher TI-IFN production by pDC. In conclusion, the PRV Bartha vaccine strain triggers strongly increased TI-IFN production by porcine pDC. Our data further indicate that the gE/gI glycoprotein complex suppresses TI-IFN production by pDC, which represents the first alphaherpesvirus factor that suppresses pDC activity. IMPORTANCE Several alphaherpesviruses, including herpes simpex virus, still lack effective vaccines. However, the highly successful Bartha vaccine has contributed substantially to eradication of the porcine alphaherpesvirus pseudorabies virus (PRV) in several countries. The

SLC6A1 Mutation and Ketogenic Diet in Epilepsy With Myoclonic-Atonic Seizures.

PubMed

Palmer, Samantha; Towne, Meghan C; Pearl, Phillip L; Pelletier, Renee C; Genetti, Casie A; Shi, Jiahai; Beggs, Alan H; Agrawal, Pankaj B; Brownstein, Catherine A

2016-11-01

Epilepsy with myoclonic-atonic seizures, also known as myoclonic-astatic epilepsy or Doose syndrome, has been recently linked to variants in the SLC6A1 gene. Epilepsy with myoclonic-atonic seizures is often refractory to antiepileptic drugs, and the ketogenic diet is known for treating medically intractable seizures, although the mechanism of action is largely unknown. We report a novel SLC6A1 variant in a patient with epilepsy with myoclonic-atonic seizures, analyze its effects, and suggest a mechanism of action for the ketogenic diet. We describe a ten-year-old girl with epilepsy with myoclonic-atonic seizures and a de novo SLC6A1 mutation who responded well to the ketogenic diet. She carried a c.491G>A mutation predicted to cause p.Cys164Tyr amino acid change, which was identified using whole exome sequencing and confirmed by Sanger sequencing. High-resolution structural modeling was used to analyze the likely effects of the mutation. The SLC6A1 gene encodes a transporter that removes gamma-aminobutyric acid from the synaptic cleft. Mutations in SLC6A1 are known to disrupt the gamma-aminobutyric acid transporter protein 1, affecting gamma-aminobutyric acid levels and causing seizures. The p.Cys164Tyr variant found in our study has not been previously reported, expanding on the variants linked to epilepsy with myoclonic-atonic seizures. A 10-year-old girl with a novel SLC6A1 mutation and epilepsy with myoclonic-atonic seizures had an excellent clinical response to the ketogenic diet. An effect of the diet on gamma-aminobutyric acid reuptake mediated by gamma-aminobutyric acid transporter protein 1 is suggested. A personalized approach to epilepsy with myoclonic-atonic seizures patients carrying SLC6A1 mutation and a relationship between epilepsy with myoclonic-atonic seizures due to SLC6A1 mutations, GABAergic drugs, and the ketogenic diet warrants further exploration. Copyright © 2016 Elsevier Inc. All rights reserved.

Strain improvement of Lactobacillus lactis for D-lactic acid production.

PubMed

Joshi, D S; Singhvi, M S; Khire, J M; Gokhale, D V

2010-04-01

Three mutants, isolated by repeated UV mutagenesis of Lactobacillus lactis NCIM 2368, produced increased D: -lactic acid concentrations. These mutants were compared with the wild type using 100 g hydrolyzed cane sugar/l in the fermentation medium. One mutant, RM2-24, produced 81 g lactic acid/l which was over three times that of the wild type. The highest D: -lactic acid (110 g/l) in batch fermentation was obtained with 150 g cane sugar/l with a 73% lactic acid yield. The mutant utilizes cellobiose efficiently, converting it into D-lactic acid suggesting the presence of cellobiase. Thus, this strain could be used to obtain D-lactic acid from cellulosic materials that are pre-hydrolyzed with cellulase.

In SilicoModel-driven Assessment of the Effects of Brain-derived Neurotrophic Factor Deficiency on Glutamate and Gamma-Aminobutyric Acid: Implications for Understanding Schizophrenia Pathophysiology.

PubMed

Agrawal, Rimjhim; Kalmady, Sunil Vasu; Venkatasubramanian, Ganesan

2017-05-31

Deficient brain-derived neurotrophic factor (BDNF) is one of the important mechanisms underlying the neuroplasticity abnormalities in schizophrenia. Aberration in BDNF signaling pathways directly or circuitously influences neurotransmitters like glutamate and gamma-aminobutyric acid (GABA). For the first time, this study attempts to construct and simulate the BDNF-neurotransmitter network in order to assess the effects of BDNF deficiency on glutamate and GABA. Using CellDesigner, we modeled BDNF interactions with calcium influx via N-methyl-D-aspartate receptor (NMDAR)- Calmodulin activation; synthesis of GABA via cell cycle regulators protein kinase B, glycogen synthase kinase and β-catenin; transportation of glutamate and GABA. Steady state stability, perturbation time-course simulation and sensitivity analysis were performed in COPASI after assigning the kinetic functions, optimizing the unknown parameters using random search and genetic algorithm. Study observations suggest that increased glutamate in hippocampus, similar to that seen in schizophrenia, could potentially be contributed by indirect pathway originated from BDNF. Deficient BDNF could suppress Glutamate decarboxylase 67-mediated GABA synthesis. Further, deficient BDNF corresponded to impaired transport via vesicular glutamate transporter, thereby further increasing the intracellular glutamate in GABAergic and glutamatergic cells. BDNF also altered calcium dependent neuroplasticity via NMDAR modulation. Sensitivity analysis showed that Calmodulin, cAMP response element-binding protein (CREB) and CREB regulated transcription coactivator-1 played significant role in this network. The study presents in silico quantitative model of biochemical network constituting the key signaling molecules implicated in schizophrenia pathogenesis. It provides mechanistic insights into putative contribution of deficient BNDF towards alterations in neurotransmitters and neuroplasticity that are consistent with current

In Silico Model-driven Assessment of the Effects of Brain-derived Neurotrophic Factor Deficiency on Glutamate and Gamma-Aminobutyric Acid: Implications for Understanding Schizophrenia Pathophysiology

PubMed Central

Agrawal, Rimjhim; Kalmady, Sunil Vasu; Venkatasubramanian, Ganesan

2017-01-01

Objective Deficient brain-derived neurotrophic factor (BDNF) is one of the important mechanisms underlying the neuroplasticity abnormalities in schizophrenia. Aberration in BDNF signaling pathways directly or circuitously influences neurotransmitters like glutamate and gamma-aminobutyric acid (GABA). For the first time, this study attempts to construct and simulate the BDNF-neurotransmitter network in order to assess the effects of BDNF deficiency on glutamate and GABA. Methods Using CellDesigner, we modeled BDNF interactions with calcium influx via N-methyl-D-aspartate receptor (NMDAR)-Calmodulin activation; synthesis of GABA via cell cycle regulators protein kinase B, glycogen synthase kinase and β-catenin; transportation of glutamate and GABA. Steady state stability, perturbation time-course simulation and sensitivity analysis were performed in COPASI after assigning the kinetic functions, optimizing the unknown parameters using random search and genetic algorithm. Results Study observations suggest that increased glutamate in hippocampus, similar to that seen in schizophrenia, could potentially be contributed by indirect pathway originated from BDNF. Deficient BDNF could suppress Glutamate decarboxylase 67-mediated GABA synthesis. Further, deficient BDNF corresponded to impaired transport via vesicular glutamate transporter, thereby further increasing the intracellular glutamate in GABAergic and glutamatergic cells. BDNF also altered calcium dependent neuroplasticity via NMDAR modulation. Sensitivity analysis showed that Calmodulin, cAMP response element-binding protein (CREB) and CREB regulated transcription coactivator-1 played significant role in this network. Conclusion The study presents in silico quantitative model of biochemical network constituting the key signaling molecules implicated in schizophrenia pathogenesis. It provides mechanistic insights into putative contribution of deficient BNDF towards alterations in neurotransmitters and

Presynaptic (Type III) cells in mouse taste buds sense sour (acid) taste.

PubMed

Huang, Yijen A; Maruyama, Yutaka; Stimac, Robert; Roper, Stephen D

2008-06-15

Taste buds contain two types of cells that directly participate in taste transduction - receptor (Type II) cells and presynaptic (Type III) cells. Receptor cells respond to sweet, bitter and umami taste stimulation but until recently the identity of cells that respond directly to sour (acid) tastants has only been inferred from recordings in situ, from behavioural studies, and from immunostaining for putative sour transduction molecules. Using calcium imaging on single isolated taste cells and with biosensor cells to identify neurotransmitter release, we show that presynaptic (Type III) cells specifically respond to acid taste stimulation and release serotonin. By recording responses in cells isolated from taste buds and in taste cells in lingual slices to acetic acid titrated to different acid levels (pH), we also show that the active stimulus for acid taste is the membrane-permeant, uncharged acetic acid moiety (CH(3)COOH), not free protons (H(+)). That observation is consistent with the proximate stimulus for acid taste being intracellular acidification, not extracellular protons per se. These findings may also have implications for other sensory receptors that respond to acids, such as nociceptors.

γ-Aminobutyric acid (GABA) oral rinse reduces capsaicin-induced burning mouth pain sensation: An experimental quantitative sensory testing study in healthy subjects.

PubMed

Zhang, Y; Wang, K; Arendt-Nielsen, L; Cairns, B E

2018-02-01

In burning mouth patients, analgesia after oral administration of clonazepam may result from modulation of peripheral γ-aminobutyric acid (GABA) receptors. The effect of oral administration of test solutions (water, 0.5 mol/L or 0.05 mol/L GABA, 1% lidocaine) was investigated for the amelioration of pain and sensitivity induced by application of capsaicin (1%, 2 min) to the tongue of thirty healthy male and female subjects in this four-session, randomized, placebo-controlled, double-blinded, cross-over study. Intra-oral quantitative sensory testing was used to assess cold (CDT), warm (WDT) and mechanical (MDT) detection thresholds as well as mechanical (MPT) and heat (HPT) pain thresholds. Capsaicin-induced pain intensity was continuously rated on a 0-10 electronic visual analogue scale (VAS). The area under the VAS curve (VASAUC) after rinsing was calculated for each solution. Capsaicin application on the tongue evoked burning pain with a peak of 4.8/10, and significantly increased CDT and MDT while significantly decreasing WDT, HPT, and MPT. The VASAUC was significantly smaller after oral rinse with 0.05 mol/L GABA, 0.5 mol/L GABA, and 1% lidocaine than after oral rinse with water. Rinse with 0.5 mol/L or 0.05 mol/L GABA were similarly effective in decreasing VASAUC. Rinsing with either 1% lidocaine, 0.5 mol/L or 0.05 mol/L GABA also significantly attenuated the effects of capsaicin on WDT and HPT in a treatment independent manner. There were no sex-related differences in these effects of GABA. Capsaicin-induced burning tongue pain and decreases in WDT and HPT can be ameliorated by rinsing the mouth with lidocaine and GABA solutions. Rinsing the mouth with an oral GABA containing solution ameliorated burning pain and increased heat sensitivity produced by application of capsaicin to the tongue. This finding suggests that GABA can act as a local analgesic agent in the oral cavity. © 2017 European Pain Federation - EFIC®.

Transfer of Asymmetry between Proteinogenic Amino Acids under Harsh Conditions

NASA Astrophysics Data System (ADS)

Tarasevych, Arkadii V.; Vives, Thomas; Snytnikov, Valeriy N.; Guillemin, Jean-Claude

2017-09-01

The heating above 400 °C of serine, cysteine, selenocysteine and threonine leads to a complete decomposition of the amino acids and to the formation in low yields of alanine for the three formers and of 2-aminobutyric acid for the latter. At higher temperature, this amino acid is observed only when sublimable α-alkyl-α-amino acids are present, and with an enantiomeric excess dependent on several parameters. Enantiopure or enantioenriched Ser, Cys, Sel or Thr is not able to transmit its enantiomeric excess to the amino acid formed during its decomposition. The presence during the sublimation-decomposition of enantioenriched valine or isoleucine leads to the enantioenrichment of all sublimable amino acids independently of the presence of many decomposition products coming from the unstable derivative. All these studies give information on a potentially prebiotic key-reaction of abiotic transformations between α-amino acids and their evolution to homochirality.

Interaction of humic acids and humic-acid-like polymers with herpes simplex virus type 1

NASA Astrophysics Data System (ADS)

Klöcking, Renate; Helbig, Björn

The study was performed in order to compare the antiviral activity against herpes simplex virus type 1 (HSV-1) of synthetic humic-acid-like polymers to that of their low-molecular-weight basic compounds and naturally occurring humic acids (HA) in vitro. HA from peat water showed a moderate antiviral activity at a minimum effective concentration (MEC) of 20 µg/ml. HA-like polymers, i.e. the oxidation products of caffeic acid (KOP), hydrocaffeic acid (HYKOP), chlorogenic acid (CHOP), 3,4-dihydroxyphenylacetic acid (3,4-DHPOP), nordihydroguaretic acid (NOROP), gentisinic acid (GENOP), pyrogallol (PYROP) and gallic acid (GALOP), generally inhibit virus multiplication, although with different potency and selectivity. Of the substances tested, GENOP, KOP, 3,4-DHPOP and HYKOP with MEC values in the range of 2 to 10 µg/ml, proved to be the most potent HSV-1 inhibitors. Despite its lower antiviral potency (MEC 40 µg/ml), CHOP has a remarkable selectivity due to the high concentration of this polymer that is tolerated by the host cells (>640 µg/ml). As a rule, the antiviral activity of the synthetic compounds was restricted to the polymers and was not preformed in the low-molecular-weight basic compounds. This finding speaks in favour of the formation of antivirally active structures during the oxidative polymerization of phenolic compounds and, indirectly, of corresponding structural parts in different HA-type substances.

Non-avoidance behaviour in enchytraeids to boric acid is related to the GABAergic mechanism.

PubMed

Bicho, Rita C; Gomes, Susana I L; Soares, Amadeu M V M; Amorim, Mónica J B

2015-05-01

Soil invertebrates, e.g. enchytraeids, are known to be able to avoid unfavourable conditions, which gives them an important ecological advantage. These organisms possess chemoreceptors that can detect stressors, which in turn activate responses such as avoidance behaviour. We studied the avoidance behaviour in response to boric acid (BA) using enchytraeids. Results showed not only no avoidance, but that increasing concentrations seemed to have an "attraction" effect. To study the underlying mechanism, a selection of genes targeting for neurotransmission pathways (acetylcholinesterase (AChE) and gamma-aminobutyric acid receptor (GABAr)) were quantified via quantitative real-time polymerase chain reaction (qPCR). Evidences were that BA is neurotoxic via the GABAergic system mechanism where it acts as a GABA-associated protein receptor (GABAAR) antagonist possibly causing anaesthetic effects. This is the first time that (non)avoidance behaviour in invertebrates was studied in relation with the GABAergic system. We strongly recommend the combination of such gene and/or functional assay studies with the avoidance behaviour test as it can bring many advantages and important interpretation lines for ecotoxicity with minor effort.

Polymorphisms of endothelin 1 (G5665T and T-1370G) and endothelin receptor type A (C+70G and G-231A) in Graves' disease.

PubMed

Aydın, A Fatih; Develi-İş, Seval; Doğru-Abbasoğlu, Semra; Vural, Pervin; Ozderya, Ayşenur; Karadağ, Berrin; Uysal, Müjdat

2014-01-01

Endothelin 1 (EDN1) is a strong angiogenic and mitogenic factor, playing a key role in hypervascularization, thyroid follicle cell hyperplasia, and lymphocyte infiltration in the thyroid gland of patients with Graves' disease (GD). EDN1 induces angiogenesis and mitogenesis via endothelin receptor type A (EDNRA). This study examined the possible association of EDN1 (G5665T and T-1370G) and EDNRA (C+70G and G-231A) single nucleotide polymorphisms (SNPs) with the occurrence of GD, and evaluates the relationship between genotypes and clinical/laboratory manifestations of GD. We analyzed genotype and allele distributions of EDN1 and EDNRA polymorphisms in 165 patients with GD and 181 healthy controls by real-time PCR combined with melting curve analysis. No significant associations between GD and variant alleles of the studied polymorphisms were observed. However, the anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) levels in EDN1 G5665T GG genotype were higher than those in T allele carriers (GT+TT) (p=0.001 and p=0.026, respectively). In addition, anti-TPO levels in EDN1 T-1370G wild-type homozygous patients were found to be higher than in mutant gene carrying patients (GT+GG) (p=0.006). The presence of EDNRA+70G allele was associated with 3.37-fold increased risk for development of ophthalmopathy in GD patients (p=0.009). Although there were no associations between EDN1 (G5665T and T-1370G) and EDNRA (C+70G and G-231A) SNPs and susceptibility to GD, EDN1 G5665T and T-1370G polymorphisms were related to alterations of autoantibody production and EDNRA C+70G polymorphism is related with increased risk for ophthalmopathy in GD patients. Copyright © 2013 Elsevier B.V. All rights reserved.

Oxidation of fatty acid may be enhanced by a combination of pomegranate fruit phytochemicals and acetic acid in HepG2 cells.

PubMed

Kim, Ji Yeon; Ok, Elly; Kim, You Jin; Choi, Kyoung-Sook; Kwon, Oran

2013-06-01

We investigated whether the combination of phytochemicals and acetic acid in the form of fruit vinegar provides an additive effect on changes of mRNA levels related to fatty acid oxidation in human hepatocyte (HepG2). Among the seven fruit vinegars (Rubuscoreanus, Opuntia, blueberry, cherry, red ginseng, mulberry, and pomegranate) studied, treatment of HepG2 with pomegranate vinegar (PV) at concentrations containing 1 mM acetic acid showed the highest in vitro potentiating effect on the mRNA expression levels of peroxisome proliferator-activated receptor α, carnitinepalmitoyl transferase-1, and acyl-CoA oxidase compared to the control group (P < 0.05). Reversed-phase liquid chromatography in combination with quadrupole time-of-flight mass spectrometry analysis revealed four potential compounds (punicalagin B, ellagic acid, and two unidentified compounds) responsible for altered gene expression in HepG2 cells treated with PV as compared with the others. Further investigations are warranted to determine if drinking PV beverages may help to maintain a healthy body weight in overweight subjects.

A novel homozygous no-stop mutation in G6PC gene from a Chinese patient with glycogen storage disease type Ia.

PubMed

Gu, Lei-Lei; Li, Xin-Hua; Han, Yue; Zhang, Dong-Hua; Gong, Qi-Ming; Zhang, Xin-Xin

2014-02-25

Glycogen storage disease type Ia (GSD-Ia) is an autosomal recessive genetic disorder resulting in hypoglycemia, hepatomegaly and growth retardation. It is caused by mutations in the G6PC gene encoding Glucose-6-phosphatase. To date, over 80 mutations have been identified in the G6PC gene. Here we reported a novel mutation found in a Chinese patient with abnormal transaminases, hypoglycemia, hepatomegaly and short stature. Direct sequencing of the coding region and splicing-sites in the G6PC gene revealed a novel no-stop mutation, p.*358Yext*43, leading to a 43 amino-acid extension of G6Pase. The expression level of mutant G6Pase transcripts was only 7.8% relative to wild-type transcripts. This mutation was not found in 120 chromosomes from 60 unrelated healthy control subjects using direct sequencing, and was further confirmed by digestion with Rsa I restriction endonuclease. In conclusion, we revealed a novel no-stop mutation in this study which expands the spectrum of mutations in the G6PC gene. The molecular genetic analysis was indispensable to the diagnosis of GSD-Ia for the patient. Copyright © 2013 Elsevier B.V. All rights reserved.

Structural basis for amino acid export by DMT superfamily transporter YddG.

PubMed

Tsuchiya, Hirotoshi; Doki, Shintaro; Takemoto, Mizuki; Ikuta, Tatsuya; Higuchi, Takashi; Fukui, Keita; Usuda, Yoshihiro; Tabuchi, Eri; Nagatoishi, Satoru; Tsumoto, Kouhei; Nishizawa, Tomohiro; Ito, Koichi; Dohmae, Naoshi; Ishitani, Ryuichiro; Nureki, Osamu

2016-06-16

The drug/metabolite transporter (DMT) superfamily is a large group of membrane transporters ubiquitously found in eukaryotes, bacteria and archaea, and includes exporters for a remarkably wide range of substrates, such as toxic compounds and metabolites. YddG is a bacterial DMT protein that expels aromatic amino acids and exogenous toxic compounds, thereby contributing to cellular homeostasis. Here we present structural and functional analyses of YddG. Using liposome-based analyses, we show that Escherichia coli and Starkeya novella YddG export various amino acids. The crystal structure of S. novella YddG at 2.4 Å resolution reveals a new membrane transporter topology, with ten transmembrane segments in an outward-facing state. The overall structure is basket-shaped, with a large substrate-binding cavity at the centre of the molecule, and is composed of inverted structural repeats related by two-fold pseudo-symmetry. On the basis of this intramolecular symmetry, we propose a structural model for the inward-facing state and a mechanism of the conformational change for substrate transport, which we confirmed by biochemical analyses. These findings provide a structural basis for the mechanism of transport of DMT superfamily proteins.

Retention of heavy metal ions on comb-type hydrogels based on acrylic acid and 4-vinylpyridine, synthesized by gamma radiation

NASA Astrophysics Data System (ADS)

González-Gómez, Roberto; Ortega, Alejandra; Lazo, Luz M.; Burillo, Guillermina

2014-09-01

Two novel comb-type hydrogels based on pH-sensitive monomers (acrylic acid (AAc) and 4-vinylpyridine (4VP) were synthesized by gamma radiation. The systems were as follows: a) comb-type hydrogels of an AAc network followed by grafting of 4VP ((net-PAAc)-g-4VP) and b) comb-type hydrogels of an AAc network grafted onto polypropylene (PP) followed by grafting of 4VP (net-(PP-g-AAc)-g-4VP). The equilibrium isotherms and kinetics were evaluated for copper and zinc ions in aqueous solutions. The Zn(II) retention obtained was 480 mg g-1 and 1086 mg g-1 for (net-PAAc)-g-4VP and net-(PP-g-AAc)-g-4VP, respectively. At concentrations as low as ppm, retention efficiencies of approximately 90% were achieved for Cu(II) on (net-PAAc)-g-4VP and for Zn(II) on net-(PP-g-AAc)-g-4VP. Desorption of the hydrogels was also studied, and the results indicated that they can be used repeatedly in aqueous solutions. For both systems, the adsorption of Cu(II) and Zn(II) obeyed the Freundlich model, indicating heterogeneous sorption, and the retention process occurred by chemisorption. The sorption process follows a pseudo-second-order model.

Epoxy Stearic Acid, an Oxidative Product Derived from Oleic Acid, Induces Cytotoxicity, Oxidative Stress, and Apoptosis in HepG2 Cells.

PubMed

Liu, Ying; Cheng, Yajun; Li, Jinwei; Wang, Yuanpeng; Liu, Yuanfa

2018-05-23

In the present study, effects of cis-9,10-epoxy stearic acid (ESA) generated by the thermal oxidation of oleic acid on HepG2 cells, including cytotoxicity, apoptosis, and oxidative stress, were investigated. Our results revealed that ESA decreased the cell viability and induced cell death. Cell cycle analysis with propidium iodide staining showed that ESA induced cell cycle arrest at the G0/G1 phase in HepG2 cells. Cell apoptosis analysis with annexin V and propidium iodide staining demonstrated that ESA induced HepG2 cell apoptotic events in a dose- and time-dependent manner; the apoptosis of cells after treated with 500 μM ESA for 12, 24, and 48 h was 32.16, 38.70, and 65.80%, respectively. Furthermore, ESA treatment to HepG2 cells resulted in an increase in reactive oxygen species and malondialdehyde (from 0.84 ± 0.02 to 8.90 ± 0.50 nmol/mg of protein) levels and a reduction in antioxidant enzyme activity, including superoxide dismutase (from 1.34 ± 0.27 to 0.10 ± 0.007 units/mg of protein), catalase (from 100.04 ± 5.05 to 20.09 ± 3.00 units/mg of protein), and glutathione peroxidase (from 120.44 ± 7.62 to 35.84 ± 5.99 milliunits/mg of protein). These findings provide critical information on the effects of ESA on HepG2 cells, particularly cytotoxicity and oxidative stress, which is important for the evaluation of the biosafety of the oxidative product of oleic acid.

Hypothesis: Could Excessive Fructose Intake and Uric Acid Cause Type 2 Diabetes?

PubMed Central

Johnson, Richard J.; Perez-Pozo, Santos E.; Sautin, Yuri Y.; Manitius, Jacek; Sanchez-Lozada, Laura Gabriela; Feig, Daniel I.; Shafiu, Mohamed; Segal, Mark; Glassock, Richard J.; Shimada, Michiko; Roncal, Carlos; Nakagawa, Takahiko

2009-01-01

We propose that excessive fructose intake (>50 g/d) may be one of the underlying etiologies of metabolic syndrome and type 2 diabetes. The primary sources of fructose are sugar (sucrose) and high fructose corn syrup. First, fructose intake correlates closely with the rate of diabetes worldwide. Second, unlike other sugars, the ingestion of excessive fructose induces features of metabolic syndrome in both laboratory animals and humans. Third, fructose appears to mediate the metabolic syndrome in part by raising uric acid, and there are now extensive experimental and clinical data supporting uric acid in the pathogenesis of metabolic syndrome. Fourth, environmental and genetic considerations provide a potential explanation of why certain groups might be more susceptible to developing diabetes. Finally, we discuss the counterarguments associated with the hypothesis and a potential explanation for these findings. If diabetes might result from excessive intake of fructose, then simple public health measures could have a major impact on improving the overall health of our populace. PMID:19151107

[Ursodeoxycholic acid induced apoptosis of human hepatoma cells HepG2 and SMMC-7721 bymitochondrial-mediated pathway].

PubMed

Wu, Duan; Zhou, Jianyin; Yin, Zhenyu; Liu, Pingguo; Zhao, Yilin; Liu, Jianming; Wang, Xiaomin

2014-12-02

To explore the effects and underlying mechanisms of ursodeoxycholic acid on human hepatoma cells. HepG2 and SMMC-7721 HCC cell lines were respectively treated with ursodeoxycholic acid. And cell proliferation, apoptosis and the expression of Bax/Bcl-2 gene were detected by methyl thiazolyl tetrazolium (MTT), inverted microscopy, fluorescent microscopy, flow cytometry and Western blot. Ursodeoxycholic acid significantly inhibited the proliferation of human hepatoma cells in a concentration- and time-dependent manner. The half maximal inhibitory concentrations (IC50) of HepG2 and SMMC-7721 were 397.3 and 387.7 µg/ml respectively after a 48-hour treatment of 400 µg /ml ursodeoxycholic acid. And it also induced the apoptosis of HepG2 and SMMC-7721 cells, up-regulated Bax gene and down-regulated Bcl-2 gene. Ursodeoxycholic acid inhibits the proliferation of hepatoma cells and induce apoptosis by mitochondrial-mediated pathway.

Relative stability of major types of beta-turns as a function of amino acid composition: a study based on Ab initio energetic and natural abundance data.

PubMed

Perczel, András; Jákli, Imre; McAllister, Michael A; Csizmadia, Imre G

2003-06-06

Folding properties of small globular proteins are determined by their amino acid sequence (primary structure). This holds both for local (secondary structure) and for global conformational features of linear polypeptides and proteins composed from natural amino acid derivatives. It thus provides the rational basis of structure prediction algorithms. The shortest secondary structure element, the beta-turn, most typically adopts either a type I or a type II form, depending on the amino acid composition. Herein we investigate the sequence-dependent folding stability of both major types of beta-turns using simple dipeptide models (-Xxx-Yyy-). Gas-phase ab initio properties of 16 carefully selected and suitably protected dipeptide models (for example Val-Ser, Ala-Gly, Ser-Ser) were studied. For each backbone fold most probable side-chain conformers were considered. Fully optimized 321G RHF molecular structures were employed in medium level [B3LYP/6-311++G(d,p)//RHF/3-21G] energy calculations to estimate relative populations of the different backbone conformers. Our results show that the preference for beta-turn forms as calculated by quantum mechanics and observed in Xray determined proteins correlates significantly.

Molecular architectures of benzoic acid-specific type III polyketide synthases

PubMed Central

Stewart, Charles; Woods, Kate; Macias, Greg; Allan, Andrew C.; Noel, Joseph P.

2017-01-01