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BackgroundSalicornia neei is a halophyte plant that has been proposed for use in the phytoremediation of the saline wastewater generated by land-based aquaculture, which usually contains elevated concentrations of ammonium resulting from protein metabolism. To identify the molecular mechanisms related to ammonium response, we analyzed the transcriptome of S. neei in response to growth in saline water containing 3 mM ammonium and the Michaelis–Menten ammonium removal biokinetics.ResultsThe RNA sequencing generated a total of 14,680,108 paired-end reads from the control and stressed conditions. De novo assembly using the CLC Genomic Workbench produced 86,020 transcripts and a reference transcriptome with an N50 of 683 bp.A total of 45,327 genes were annotated, representing 51.2% of the contig predicted from de novo assembly. As regards DEGs, a total of 9,140 genes were differentially expressed in response to ammonium in saline water; of these, 7,396 could be annotated against functional databases. The upregulated genes were mainly involved in cell wall biosynthesis, transmembrane transport and antiporter activities, including biological KEGG pathways linked to the biosynthesis of secondary metabolites, plant hormone signal transduction, autophagy, and nitrogen metabolism. In addiction, a set of 72 genes was directly involved in ammonium metabolism, including glutamine synthetase 1 (GLN1), glutamate synthase 1 (GLT1), and ferredoxin-dependent glutamate synthase chloroplastic (Fd-GOGAT). Finally, we observed that the ammonium uptake rate increased with increasing ammonium concentrations, and tended toward saturation in the range of 3 to 4 mM.ConclusionOur results support the hypothesis that an ammonium detoxification system mediated by glutamine and glutamate synthase was activated in S. neei when exposed to ammonium and saline water. The present transcriptome profiling method could be useful when investigating the response of halophyte plants to saline wastewater from land-based aquaculture.

In humans, there are two forms of glutaminase (GLS), designated GLS1 and GLS2. These enzymes catalyse the conversion of glutamine to glutamate. GLS1 exists as two isozymes: kidney glutaminase (KGA) and glutaminase C (GAC). Several GLS inhibitors have been identified, of which DON (6‐diazo‐5‐oxonorleucine), BPTES (bis‐2‐(5‐phenylacetamido‐1, 3, 4‐thiadiazol‐2‐yl) ethyl sulphide), 968 (5‐(3‐Bromo‐4‐(dimethylamino)phenyl)‐2,2‐dimethyl‐2,3,5,6‐tetrahydrobenzo[a]phenanthridin‐4(1H)‐one) and CB839 (Telaglenastat) are the most widely used. However, these inhibitors have variable efficacy, specificity and bioavailability in research and clinical settings, implying the need for novel and improved GLS inhibitors. Based on this need, a diverse library of 28,000 compounds from Enamine was screened for inhibition of recombinant, purified GAC. From this library, one inhibitor designated compound 19 (C19) was identified with kinetic features revealing allosteric inhibition of GAC in the µm range. Moreover, C19 inhibits anti‐CD3/CD28‐induced CD4+ T‐cell proliferation and cytokine production with similar or greater potency as compared to BPTES. Taken together, our data suggest that C19 has the potential to modulate GLS1 activity and alter metabolic activity of T cells., Discovery and characterization of the novel glutamine (GLS) inhibitor C19 by high‐throughput screening from Enamine. C19 inhibits activity of GLS1 and reduces proliferation and cytokine secretion from activated CD4+ T cells.

Background: Higher circulating carotenoids are associated with lower breast cancer risk. The underlying biology remains under-explored. Methods: We profiled 293 prediagnostic plasma metabolites in a nested case–control study (n = 887 cases) within the Nurses' Health Studies. Associations between circulating carotenoids and metabolites were identified using linear-mixed models (FDR ≤ 0.05), and we further selected metabolites most predictive of carotenoids with LASSO. Metabolic signatures for carotenoids were calculated as weighted sums of LASSO selected metabolites. We further evaluated the metabolic signatures in relation to breast cancer risk using conditional logistic-regression. Results: We identified 48 to 110 metabolites associated with plasma levels of α-carotene, β-carotene, β-cryptoxanthin, estimated-vitamin-A-potential, lutein/zeaxanthin, and lycopene, which included primarily positively associated metabolites implicated in immune regulation (tryptophan), redox balance (plasmalogens, glutamine), epigenetic regulations (acetylated-/methylated-metabolites), and primarily inversely associated metabolites involved in β-oxidation (carnitines; FDR ≤ 0.05). The metabolomic signatures derived for β-carotene (Q4 vs. Q1 relative risk RR = 0.74, Ptrend = 0.02), and estimated-vitamin-A-potential (Q4 vs. Q1 RR = 0.74, Ptrend = 0.02)—measured ≥10 years before diagnosis—were associated with lower breast cancer risk. Modest attenuations of RR for measured levels of β-carotene and estimated-vitamin-A-potential were seen when we adjusted for their corresponding metabolic signatures. Conclusions: Metabolites involved in immune regulation, redox balance, membrane signaling, and β-oxidation were associated with plasma carotenoids. Although some metabolites may reflect shared common food sources or compartmental colocalization with carotenoids, others may signal the underlying pathways of carotenoids-associated lowered breast cancer risk. Impact: Consumption of carotenoid-rich diet is associated with a wide-range of metabolic changes which may help to reduce breast cancer risk.

Amino acid availability is sensed by various signaling molecules, including general control nonderepressible 2 (GCN2) and mechanistic target of rapamycin complex 1 (mTORC1). However, it is unclear how these sensors are associated with cancer cell survival under low amino acid availability. In the present study, we investigated AKT activation in non-small cell lung cancer (NSCLC) cells deprived of each one of 20 amino acids. Among the 20 amino acids, deprivation of glutamine, arginine, methionine, and lysine induced AKT activation. AKT activation was induced by GCN2/ATF4/REDD1 axis-mediated mTORC2 activation under amino acid deprivation. In CRISPR-Cas9-mediated REDD1-knockout cells, AKT activation was not induced by amino acid deprivation, indicating that REDD1 plays a major role in AKT activation under amino acid deprivation. Knockout of REDD1 sensitized cells cultured under glutamine deprivation conditions to radiotherapy. Taken together, GCN2/ATF4/REDD1 axis induced by amino acid deprivation promotes cell survival signal, which might be a potential target for cancer therapy.

A spontaneous missense mutation in the alpha II spectrin (αII) gene, replacing a highly conserved arginine 1098 with the glutamine (R1098Q), causes progressive neurodegeneration in heterozygous mutant mice. The molecular mechanism underlying this phenotype is unknown but the accumulation of 150kD αII breakdown products in brains of homozygous mutant embryos suggests an imbalance in the substrate level control of αII cleavage by calpains. This is further supported by in silico simulation predicting unmasked calpain target site and increased spectrin scaffold bending and flexibility of R1098Q mutant peptide. Here, using spectroscopic and in situ enzymatic techniques, we aimed at obtaining direct experimental support for the impact of R1098Q mutation on the αII stability and its propensity for calpain-mediated degradation. Thermal circular dichroism analyses performed on recombinant wildtype and R1098Q mutant αII peptides, composed of spectrin repeat 9–10 revealed that although both had very similar secondary structure contents, thermal stability curve profiles varied and the observed midpoint of the unfolding transition (Tm) was 5.5 °C lower for the R1098Q peptide. Yet, the dynamic light scattering profiles of both peptides closely overlapped, implying the same thermal propensity to aggregate. Calpain digestion of plate-bound αII peptides with and without added calmodulin revealed an enhancement of the R1098Q peptide digestion rate relative to WT control. In summary, these results support the unstable scaffold structure of the R1098Q peptide as contributing to its enhanced intrinsic sensitivity to calpain and suggest physiologic relevance of a proper calpain/spectrin balance in preventing neurodegeneration.

Catalytic promiscuity is the coincidental ability to catalyze non-biological reactions in the same active site as the native biological reaction. Several lines of evidence show that catalytic promiscuity plays a role in the evolution of new enzyme functions. Thus, studying catalytic promiscuity can help identify structural features that predispose an enzyme to evolve new functions. This study identifies a potentially pre-adaptive residue in a promiscuous N-succinylamino acid racemase/o-succinylbenzoate synthase (NSAR/OSBS) enzyme from Amycolatopsis sp. T-1–60. This enzyme belongs to a branch of the OSBS family which includes many catalytically promiscuous NSAR/OSBS enzymes. R266 is conserved in all members of the NSAR/OSBS subfamily. However, the homologous position is usually hydrophobic in other OSBS subfamilies, whose enzymes lack NSAR activity. The second-shell amino acid R266 is close to the catalytic acid/base K263, but it does not contact the substrate, suggesting that R266 could affect the catalytic mechanism. Mutating R266 to glutamine in Amycolatopsis NSAR/OSBS profoundly reduces NSAR activity, but moderately reduces OSBS activity. This is due to a 1000-fold decrease in the rate of proton exchange between the substrate and the general acid/base catalyst K263. This mutation is less deleterious for the OSBS reaction because K263 forms a cation-π interaction with the OSBS substrate and/or the intermediate, rather than acting as a general acid/base catalyst. Together, the data explain how R266 contributes to NSAR reaction specificity and was likely an essential preadaptation for the evolution of NSAR activity.

The Allium cepa L. (onion) crop is affected by leaf blight disease caused by Stemphylium vesicarium; the shifts that S. vesicarium infection causes in the primary metabolism of onion plants are not known. In this study, the profiling of primary metabolites obtained by nuclear magnetic resonance (1H NMR) spectroscopy of organs from onion plants uninfected (control) and infected with S. vesicarium were compared. Twenty-eight metabolites were identified in the 1H NMR spectra of onion bulbs, thirty in leaves and thirty-eight in roots. Twenty-four metabolites were the same in bulbs, leaves and roots (fructose, glucose, myo-inositol, sucrose, alanine, asparagine, 4-aminobutyrate, glutamine, glutamic acid, isoleucine, leucine, phenylalanine, tryptophan, tyrosine, valine, citric acid, formic acid, lactic acid, malic acid, pyruvic acid, adenosine, guanosine, and uridine), but galactose, proline and acetoin were only identified in leaves; and trehalose, methionine, cytidine and methanol were only found in roots. Compared to uninfected plants, the concentration of sucrose, succinic, citric and formic acids and several amino acids that participate in the tricarboxylic acid cycle were reduced; which suggest that the processes involved in energy production are reduced by the infection with S. vesicarium. The concentration of formic acid was reduced in bulbs and leaves, which indicates that might infection induces the oxidation of formic acid to CO2 under conditions of low sucrose availability in onion plants. The increases of pyruvic acid, amino acids derived from pyruvic acid (alanine, leucine and valine), glutamine, glutamic acid, nucleosides of pyrimidine and purine, and GABA could be used for the successful growth of the pathogen.

Abstract Diffuse large B-cell lymphomas (DLBCL) are broadly dependent on anaplerotic metabolism regulated by mitochondrial SIRT3. Herein we find that translational upregulation of ATF4 is coupled with anaplerotic metabolism in DLBCLs due to nutrient deprivation caused by SIRT3 driving rapid flux of glutamine into the tricarboxylic acid (TCA) cycle. SIRT3 depletion led to ATF4 downregulation and cell death, which was rescued by ectopic ATF4 expression. Mechanistically, ATF4 translation is inhibited in SIRT3-deficient cells due to the increased pools of amino acids derived from compensatory autophagy and decreased glutamine consumption by the TCA cycle. Absence of ATF4 further aggravates this state through downregulation of its target genes, including genes for amino acid biosynthesis and import. Collectively, we identify a SIRT3–ATF4 axis required to maintain survival of DLBCL cells by enabling them to optimize amino acid uptake and utilization. Targeting ATF4 translation can potentiate the cytotoxic effect of SIRT3 inhibitor to DLBCL cells. Significance: We discovered the link between SIRT3 and ATF4 in DLBCL cells, which connected lymphoma amino acid metabolism with ATF4 translation via metabolic stress signals. SIRT3–ATF4 axis is required in DLBCL cells regardless of subtype, which indicates a common metabolic vulnerability in DLBCLs and can serve as a therapeutic target. This article is highlighted in the In This Issue feature, p. 1

Glutamine synthetase (GS) is a decameric enzyme that plays a key role in nitrogen metabolism. Acetylation of the N-terminal degron (N-degron) of GS is essential for ubiquitylation and subsequent GS degradation. The full-length GS structure showed that the N-degron is buried inside the GS decamer and is inaccessible to the acetyltransferase. The structure of N-degron-truncated GS reported here reveals that the N-degron is not essential for GS decamer formation. It is also shown that the N-degron can be exposed to a solvent region through a series of conformational adjustments upon ligand binding. In summary, this study elucidated the dynamic movement of the N-degron and the possible effect of glutamine in enhancing the acetylation process.

Nutraceutical properties of mandarins are of great interest to promote their consumption. The occurrence of free amino acids in foods is relevant to assess the nutritional value of it. To learn more about the amino acids� occurrence and variability between species, a targeted metabolomics study in �Ellendale�, �Willowleaf� and �Page� varieties was performed through ion exchange liquid chromatography coupled to tandem mass spectrometry. The studied amino acids were asparagine, glutamic acid, glutamine, histidine, methionine, phenylalanine, proline, threonine and tyrosine. The difference between two consecutive seasons was evaluated, as well as the influence of fruit maturity of �Page� collected in two periods of 2015. The analytical methodology was validated. The concentration of the compounds through principal component analysis, separated well apart the three cultivars in both harvests, showing a particular profile for each of them. When comparing mature and immature cultivar �Page�, the amino acids with higher levels in mature samples were histidine, asparagine, glutamine and glutamic acid. The profiles were different due to genetic diversity, and the climatic conditions. These results add value to citric production.

Background We postulate that meningiomas undergo distinct metabolic reprogramming in tumorigenesis and unraveling their metabolic phenotypes provide new therapeutic insights. Glutamine catabolism is key to the growth and proliferation of tumors. Here, we investigated the metabolomics of freshly resected meningiomas and glutamine metabolism in patient-derived meningioma cells. Methods 1H NMR spectroscopy of tumor tissues from meningioma patients was used to differentiate the metabolite profiles of grade-I and grade-II meningiomas. Glutamine metabolism was examined using 13C/15N glutamine tracer, in 5 patient-derived meningioma cells. Results Alanine, lactate, glutamate, glutamine, and glycine were predominantly elevated only in grade-II meningiomas by 74%, 76%, 35%, 75%, and 33%, respectively, with alanine and glutamine levels being statistically significant (P ≤ .02). 13C/15N glutamine tracer experiments revealed that both grade-I and -II meningiomas actively metabolize glutamine to generate various key carbon intermediates including alanine and proline that are necessary for the tumor growth. Also, it is shown that glutaminase (GLS1) inhibitor, CB-839 is highly effective in downregulating glutamine metabolism and decreasing proliferation in meningioma cells. Conclusion Alanine and glutamine/glutamate are mainly elevated in grade-II meningiomas. Grade-I meningiomas possess relatively higher glutamine metabolism providing carbon/nitrogen for the biosynthesis of key nonessential amino acids. GLS1 inhibitor (CB-839) is very effective in downregulating glutamine metabolic pathways in grade-I meningiomas leading to decreased cellular proliferation.

Plantaricin Q7 is a bacteriocin produced by Lactobacillus plantarum Q7 with food preservation potential. Low yield is one of the bottlenecks of the wide application of plantaricin Q7. Nontargeted metabolomics was performed to reveal the mechanism of plantaricin Q7 biosynthesis. The results showed that the composition and abundance of intracellular metabolites varied significantly at key time points of plantaricin Q7 synthesis. Differential metabolic pathways were purine metabolism; pyrimidine metabolism; alanine, aspartate, and glutamate metabolism; amino acid biosynthesis; aminoacyl-tRNA biosynthesis; and ABC transporters. Differential metabolites were xanthine, deoxyadenosine, uracil, 5-methylcytosine, α-ketoglutarate, γ-aminobutyric acid, glutamate, glutamine, and tryptophan. Based on metabolomics information, the putative metabolic synthesis pathway of plantaricin Q7 was proposed. Glutamine, glutamate, and 5-methylcytosine could be critical metabolites and simulate plantaricin Q7 biosynthesis significantly (P < 0.05). Bacteriocin production was investigated by comparative metabolomics in this report, which could help to achieve higher plantaricin Q7 yield by metabolic regulation.

Amino acid neurotransmitters are responsible for many physiological and pathological processes, and their cerebral concentrations respond to external influences such as the light-dark cycle and to the synthesis, release, and recapture rhythms and form part of the biochemical relationships derived from excitatory-inhibitory (E/I), glutamine-glutamate sum (GLX), glutamatergic processing (glutamine-glutamate ratio) and excitotoxic indexes. The changes in these variables during a 24-h period (1 day) are important because they allow organisms to adapt to external stimuli and form part of physiological processes. Under pathological conditions, the damage produced by acute events may depend on diurnal variations. Therefore, it is important to analyze the extracellular levels of amino acids as well as the above-mentioned indexes over a 24-h period. We focused on determining the cerebrospinal fluid levels of different amino acid neurotransmitters, and the E/I, GLX, glutamatergic processing and excitotoxic indexes, determined by microdialysis over a 24-h cycle. Our results showed significant changes during the 24-h light/dark cycle. Specifically, we found increments in the levels of glutamate (325%), GABA (550%), glutamine (300%), glycine (194%), alanine (304%) and the GLX index (263%) throughout the day, and the maximum levels of glutamate, glutamine, glycine, and alanine were obtained during the last period of the light period. In conclusion, the concentration of some amino acid neurotransmitters and the GLX index show variations depending on the light-dark cycle.

An intermediate in the synthesis of numerous antiviral protease inhibitors is the glutamine analogue, (3S)-pyrrolid-2-one-3-yl-l-alanine. Preparations of compounds based on this pharmacophore are hindered by the lack of a reliably high yielding synthesis of protected forms of this amino acid. We describe an improved scalable route with readily available reagents and facile purification. This methodology employs γ-allylation of dimethyl N-BocGlu, further Boc N-protection, OsO4-periodate oxidation, O-Me oxime formation, and RaNi-catalyzed hydrogenolysis with concomitant cyclization under basic conditions.

The effects of glutamine dipeptide (GDP) on the growth performance, intestinal digestive enzyme activity, immune metabolism index, and gene expression of related factors of Penaeus vannamei were investigated in present study. Results showed that GDP obviously increased the weight gain rate, specific growth rate, and survival rate of P. vannamei but decreased the feed conversion ratio (FCR). The activities of amylase, protease, catalase (CAT), glutathione peroxidase (GSH-Px), and Na+–K+–ATPase in the intestine of P. vannamei fed with 0.5% and 1% GDP were significantly higher than those of the control group (P

Starting from the MLPCN probe compound ML300, a structure-based optimization campaign was initiated against the recent severe acute respiratory syndrome coronavirus (SARS-CoV-2) main protease (3CLpro). X-ray structures of SARS-CoV-1 and SARS-CoV-2 3CLpro enzymes in complex with multiple ML300-based inhibitors, including the original probe ML300, were obtained and proved instrumental in guiding chemistry toward probe compound 41 (CCF0058981). The disclosed inhibitors utilize a noncovalent mode of action and complex in a noncanonical binding mode not observed by peptidic 3CLpro inhibitors. In vitro DMPK profiling highlights key areas where further optimization in the series is required to obtain useful in vivo probes. Antiviral activity was established using a SARS-CoV-2-infected Vero E6 cell viability assay and a plaque formation assay. Compound 41 demonstrates nanomolar activity in these respective assays, comparable in potency to remdesivir. These findings have implications for antiviral development to combat current and future SARS-like zoonotic coronavirus outbreaks.

In this study, the magnetic based nanoparticle (NP) of Fe2O3@glutamine (C5H10N2O3) was synthesized to improve the Fe2O3 properties in absorbing carbon dioxide (CO2) using the base fluid of hydrous N-Methyl-2-pyrrolidone (NMP) solution (50wt.%), as a physically powerful CO2 absorbent. To do this, several nano-NMP solutions, in different weight percentages of NPs were first prepared. Then, in a batch setup, the nano-NMP solutions were directly exposed to CO2 gaseous (at the pressures of 20, 30, and 40 bar) to clarify the effects of the mass percentage of NPs and initial pressure on CO2 absorption. Results clearly illustrated that Fe2O3 nanofluid was not stable more than 0.025 wt.%. However, Fe2O3@glutamine nanofluid was stable approximately two times more than Fe2O3 nanofluid due to the presence of glutamine as a hydrophilic agent in the structure of Fe2O3@glutamine. Moreover, in comparison to the base fluid (NMP solution), although Fe2O3 increased CO2 absorption up to 9.14%, Fe2O3@glutamine NPs caused the CO2 absorption to increase up to 19.41%, which can be determined as the chemical reactions of two amino groups in the glutamine structure with CO2 and also higher Stability of Fe2O3@glutamine NPs compared to bare Fe2O3 NPs.

Background: Metabolomic analyses from our group and others have shown that tumors treated with glutamine antagonists (GA) exhibit robust accumulation of formylglycinamide ribonucleotide (FGAR), an intermediate in the de novo purine synthesis pathway. The increase in FGAR is attributed to the inhibition of the enzyme FGAR amidotransferase (FGAR-AT) that catalyzes the ATP-dependent amidation of FGAR to formylglycinamidine ribonucleotide (FGAM). While perturbation of this pathway resulting from GA therapy has long been recognized, no study has reported systematic quantitation and analyses of FGAR in plasma and tumors. Objective: Herein, we aimed to evaluate the efficacy of our recently discovered tumor-targeted GA prodrug, GA-607 (isopropyl 2-(6-acetamido-2-(adamantane-1-carboxamido)hexanamido)-6-diazo-5-oxohexanoate), and demonstrate its target engagement by quantification of FGAR in plasma and tumors. Methods: Efficacy and pharmacokinetics of GA-607 were evaluated in a murine EL4 lymphoma model followed by global tumor metabolomic analysis. Liquid chromatography-mass spectrometry (LC-MS) based methods employing the ion-pair chromatography approach were developed and utilized for quantitative FGAR analyses in plasma and tumors. Results: GA-607 showed preferential tumor distribution and robust single-agent efficacy in a murine EL4 lymphoma model. While several metabolic pathways were perturbed by GA-607 treatment, FGAR showed the highest increase qualitatively. Using our newly developed sensitive and selective LC-MS method, we showed a robust >80- and >10- fold increase in tumor and plasma FGAR levels, respectively, with GA-607 treatment. Conclusion: These studies describe the importance of FGAR quantification following GA therapy in cancer and underscore its importance as a valuable pharmacodynamic marker in the preclinical and clinical development of GA therapies.

Context Elevated concentrations of branched-chain amino acids (BCAA) are strong predictors of type 2 diabetes mellitus (T2DM). Their association with cardiovascular disease (CVD) remains uncertain, particularly in youth. Objective We investigated the role of BCAA and aromatic amino acids (AAA) in obesity, their relationships with novel biomarkers of CVD, and response to a physical activity-based lifestyle intervention (PAL-I) in a randomized controlled study in youth with normal weight (NW) and obesity (OB). Methods Age (14-18 years) and Tanner stage (≥IV) matched youth (OB, n = 15 and NW, n = 6) were studied; the 15 participants with OB underwent a 3-month randomized controlled PAL-I. Circulating amino acid profile, glucose, insulin, lipids, adiponectin, retinol binding protein-4, fibrinogen, high-sensitivity C-reactive protein, interleukin-6, and 25-hydroxy vitamin-D, along with body composition, were measured at baseline and after PAL-I. Independent t tests, analysis of covariance, and mixed-effect models were used for analysis of the data. Results Compared with NW, the concentration of various amino acids, including BCAA and AAA, were altered in OB (P 0.05) on BCAA and AAA. Glutamine, glycine, and aspartic acid decreased with PAL-I (all P Conclusion The novel finding of the BCAA–inflammation relationship, along with strong correlations with nontraditional biomarkers of CVD, may raise the prospect of BCAA as a biomarker of CVD and evoke a potential link between obesity, T2DM, and CVD.

There are marked decreases in plasma concentrations of cortisol and arginine (an essential amino acid for neonates) as well as intestinal citrulline synthesis in piglets during the first 14 days of life. The objective of this study was to test the hypothesis that increasing plasma cortisol concentrations by cortisol administration may prevent the decline in intestinal citrulline and arginine synthesis from proline, thereby possibly increasing plasma arginine concentration in suckling piglets and their growth. Seven-day-old pigs reared by sows received daily intramuscular injections of hydrocortisone 21-acetate (25 mg/kg) or vehicle solution (saline) (n = 10/group). At 14 days of age, piglets were used to prepare jejunal enterocytes. Cells were incubated at 37 °C for 30 min in oxygenated Krebs buffer containing 5 mM glucose, 2 mM [U-14C]proline, and 2 mM glutamine. Cortisol treatment increased plasma cortisol concentration, mitochondrial proline oxidase and N-acetylglutamate synthase activities, cytosolic argininosuccinate lyase activity, and the intracellular concentrations of N-acetylglutamate and carbamoyl phosphate for citrulline and arginine synthesis. However, cortisol treatment induced the expression of intestinal arginase-II for arginine hydrolysis, resulting in no change in plasma arginine concentration. Administration of cortisol had no effect on milk consumption or the whole-body growth rate of piglets, but increased villus height in the jejunum and ileum. Collectively, these results suggest an important role for proline oxidase and N-acetylglutamate in regulating citrulline and arginine synthesis from proline in pig enterocytes. Because proline catabolism plays an important role in modulating protein synthesis, cell proliferation, and arginine production, our findings may have important implications for understanding the role of proline oxidase in the growth and health of the mammalian small intestine.

Transglutaminases are protein cross‐linking and protein‐modifying enzymes that have attracted considerable interest due to their causal involvement in various diseases and versatility in industrial applications. In particular, microbial transglutaminases (MTG) from Streptomyces bacteria have managed in recent years to evolve from simple food additives to specialized enzymes for the site‐directed modification of therapeutic proteins. The review summarizes relevant studies from the beginning dealing with the occurrence, production, structure, catalysis, and substrate molecules of MTG enzymes. It also addresses biotechnological procedures with MTG from S. mobaraensis (SmMTG) as the most prominent representative in focus. Reassessment of the available data revealed unexpected insights into catalysis of SmMTG and other transglutaminases, suggesting selection of glutamine donor proteins by subsites at the front vestibule and the existence of distinct lysine pockets. Flexibility of the SmMTG‐accessible glutamine donor substrate regions seems to be more important than the glutamine environment. Nevertheless, residues in close vicinity to glutamines also determine interaction with the SmMTG subsites. The apparent lack of subsites for lysine donor proteins suggests self‐assembly of the substrate proteins prior to enzymatic cross‐linking. The study of natural substrate proteins, especially their mutual interaction, is proposed to further illuminate catalysis of SmMTG. To this end, structure and function of the characterized substrate proteins from S. mobaraensis are discussed in conclusion.

Soy saponins, as thermo-stable anti-nutrients in soybean meal (SBM), are the primary causal agents of SBM-induced enteritis, which represents a well-documented pathologic alternation involving the distal intestines of various farmed fish. Our previous work showed that soy saponins might lead to SBM-induced enteritis, destroy tight junction structure and induce oxidative damage in juvenile turbot. Glutamine, as a conditionally essential amino acid, is an important substrate utilized for the growth of intestinal epithelial cells. An 8-week feeding trial was carried out to determine whether glutamine can attenuate the detrimental effects of soy saponins. Three isonitrogenous-isolipidic experimental diets were formulated as follows: (i) fish meal-based diet (FM), considered as control; (ii) FM + 10 g/kg soy saponins, SAP; and (iii) SAP + 15 g/kg glutamine, GLN. The results showed that dietary soy saponins significantly increased the gene expression levels of inflammatory markers (IL-1β, IL-8 and TNF-α) and related signaling factors (NF-кB, AP-1, p38, JNK and ERK), which were remarkably attenuated by dietary glutamine. Compared to SAP group, GLN-fed fish exhibited significantly higher expression levels of tight junction genes (CLDN3, CLDN4, OCLN, Tricellulin and ZO-1). Glutamine supplementation in SAP diet markedly suppressed the production of reactive oxygen species, malondialdehyde and protein carbonyl, and enhanced the activities of antioxidant enzymes as well as the mRNA levels of HO-1, SOD, GPX and Nrf2. Furthermore, GLN-fed fish had a remarkably lower number of autophagosomes compared to SAP-fed fish. In conclusion, our study indicated that glutamine could reverse the harmful effects of soy saponins on intestinal inflammation, tight junction disruption and oxidative damage, via attenuation of NF-кB, AP-1 and MAPK pathways and activation of Nrf2 pathway. Glutamine may have the function of controlling autophaghic process within an appropriate level of encountering inflammation.

Background Epithelial ovarian cancer (EOC) is a common gynecological cancer with high mortality rates. The main objective of this study was to investigate the serum amino acid and organic acid profiles to distinguish key metabolites for screening EOC patients. Methods In total, 39 patients with EOC and 31 healthy controls were selected as the training set. Serum amino acid and organic acid profiles were determined using the targeted metabolomics approach. Metabolite profiles were processed via multivariate analysis to identify potential metabolites and construct a metabolic network. Finally, a test dataset derived from 29 patients and 28 healthy controls was constructed to validate the potential metabolites. Results Distinct amino acid and organic acid profiles were obtained between EOC and healthy control groups. Methionine, glutamine, asparagine, glutamic acid and glycolic acid were identified as potential metabolites to distinguish EOC from control samples. The areas under the curve for methionine, glutamine, asparagine, glutamic acid and glycolic acid were 0.775, 0 778, 0.955, 0.874 and 0.897, respectively, in the validation study. Metabolic network analysis of the training set indicated key roles of alanine, aspartate and glutamate metabolism as well as D-glutamine and D-glutamate metabolism in the pathogenesis of EOC. Conclusions Amino acid and organic acid profiles may serve as potential screening tools for EOC. Data from this study provide useful information to bridge gaps in the understanding of the amino acid and organic acid alterations associated with epithelial ovarian cancer.

Glutamine (Gln) is essential for cancer progression, however, few studies have been conducted to investigate the roles of Gln transporters in gastric cancer stem cells (CSCs). This work aims to explore the roles of Gln transporters in gastric cancer cell stemness. We collected spheres formed by gastric cancer (GC) cells through a 3-dimensional (3D) semisolid culture system which has been shown to hold CSC-like traits. Lentivirus package was used to construct GC cells with SNAT2 overexpression. Analysis of sphere-formation, stemness marker expression, ALDH activity were used to detect the effects of Gln transporters on GC cell stemness. Determination of reactive oxygen species (ROS) and Gln consumption combined with the methods analyzing cell stemness were performed to explore the underlying mechanisms. Gln consumption was upregulated in GC spheres compared to the parental GC cells. The Gln transporter SNAT2 was highly expressed in GC spheres compared to that in the parental GC cells. SNAT2 overexpression significantly increased the Gln consumption in GC cells and increased the expression of stemness markers, sphere-formation ability and ALDH activity. Notably, SNAT2-mediated promoting effects on GC cell stemness were rescued by Gln deprivation. What’s more, high expression of SNAT2 was associated with a poor GC patient survival through different online datasets. SNAT2 can promote the stemness of GC cells in a Gln-dependent manner.

Aims/Introduction Glutamine is the most abundant amino acid in the circulation. In this study, we investigated cell signaling in the amplification of insulin secretion by glutamine. Materials and Methods Clonal pancreatic β‐cells MIN6‐K8, wild‐type B6 mouse islets, glutamate dehydrogenase (GDH) knockout clonal β‐cells (Glud1KOβCL), and glutamate‐oxaloacetate transaminase 1 (GOT1) knockout clonal β‐cells (Got1KOβCL) were studied. Insulin secretion from these cells and islets was examined under various conditions, and intracellular glutamine metabolism was assessed by metabolic flux analysis. Intracellular Ca2+ concentration ([Ca2+]i) was also measured. Results Glutamine dose‐dependently amplified insulin secretion in the presence of high glucose in both MIN6‐K8 cells and Glud1KOβCL. Inhibition of glutaminases, the enzymes that convert glutamine to glutamate, dramatically reduced the glutamine‐amplifying effect on insulin secretion. A substantial amount of glutamate was produced from glutamine through direct conversion by glutaminases. Glutamine also increased [Ca2+]i at high glucose, which was abolished by inhibition of glutaminases. Glutamic acid dimethylester (dm‐Glu), a membrane permeable glutamate precursor that is converted to glutamate in cells, increased [Ca2+]i as well as induced insulin secretion at high glucose. These effects of glutamine and dm‐Glu were dependent on calcium influx. Glutamine also induced insulin secretion in clonal β‐cells MIN6‐m14, which otherwise exhibit no insulin secretory response to glucose. Conclusions Glutamate converted from glutamine is an essential mediator that enhances calcium signaling in the glutamine‐amplifying effect on insulin secretion. Our data also suggest that glutamine exerts a permissive effect on glucose‐induced insulin secretion., Glutamine amplifies glucose‐induced insulin secretion through its conversion to glutamate. Glutamate converted from glutamine functions as an essential mediator that enhances calcium signaling in glutamine‐amplified insulin secretion.

Amino acids are indispensable nutrients for both normal and cancer cells. Cancer cells are unable to synthesize essential amino acids as well as some non‐essential amino acids adequately to support rapid proliferation, and must take up amino acids from the surroundings. To meet the increased demand for the amino acid needed for proliferation, high levels of amino acid transporters are expressed on the surface of cancer cells. Cancer cells utilize amino acids to synthesize proteins and nucleotides, as well as to obtain energy. In addition, amino acids are known to play pathological roles in cancer cells. Interestingly, breast cancer cells limit the use of amino acids for cell proliferation based on amino acid availability, which depends on estrogen receptor status. Here, we present a summarized literature review of novel amino acid functions in cancer cells. This review organizes the available knowledge on 2 amino acid transporters, SLC7A5 and SLC7A11, which are considered essential for breast cancer cell growth in a cell‐dependent manner. In particular, we propose the glutamine recycling model to clarify the mechanism underlying aberrant SLC7A5 activation. Finally, we overview the pathological significances of SLC7A5 and SLC7A11 in cancer tissues., Amino acids are indispensable nutrients for cancer cells. Cancer cells are unable to synthesize essential amino acids as well as some non‐essential amino acids adequately to support rapid proliferation, and must uptake amino acids from the surroundings. In order to meet the increased demand for amino acids needed for proliferation, high levels of amino acid transporters are expressed on the surface of cancer cells. This review organizes the knowledge available on two amino acid transporters, SLC7A5 and SLC7A11, which are considered essential for breast cancer cell growth in a cell‐dependent manner.

Background: Human Papilloma Virus (HPV) is the primary cause of cancers in cervix, head and neck regions. Oncoprotein E6 of HPV-16, after infecting human body, alters host protein- protein interaction networks. E6 interacts with several proteins, causing the infection to progress into cervical cancer. The molecular basis for these interactions is the presence of short linear peptide motifs on E6 identical to those on human proteins. Methods: Motifs of LXXLL and E/DLLL/V-G after identification on E6, were analyzed for their dynamic fluctuations by use of elastic network models. Correlation analysis of amino acid residues of E6 was also performed in specific regions of motifs. Results: Arginine, Leucine, Glutamine, Threonine and Glutamic acid have been identified as hot spot residues of E6 which can subsequently provide a platform for drug designing and understanding of pathogenesis of cervical cancer. These amino acids play a significant role in stabilizing interactions with host proteins, ultimately causing infections and cancers. Conclusion: Our study validates the role of linear binding motifs of E6 of HPV in interacting with these proteins as an important event in the propagation of HPV in human cells and its transformation into cervical cancer. The study further predicts the domains of protein kinase and armadillo as part of the regions involved in the interaction of E6AP, Paxillin and TNF R1, with viral E6.

Introduction: Amino acids are key elements in the regulation of the aging process which entails a progressive loss of muscle mass. The health effects of plasma amino acids can be influenced by dietary intake. This study assessed the prospective association between amino acid species and impaired lower-extremity function (ILEF) in older adults, exploring the role of diet on this association. Methods: This is a case-control design comprising 43 incident cases of ILEF and 85 age- and sex-matched controls. Plasma concentrations of 20 amino acid species were measured at baseline using liquid chromatography-tandem mass spectrometry, and incident cases of ILEF were measured after 2 years by means of the Short Physical Performance Battery. Conditional logistic regression models were used to assess longitudinal relationships. Results: After adjusting for potential confounders, higher levels of tryptophan were associated with a decreased 2-year risk of ILEF (OR per 1-SD increase = 0.64, 95% CI = [0.42, 0.97]), while glutamine and total essential amino acids were linked to higher ILEF risk (OR = 1.57, 95% CI = [1.01, 2.45]; OR = 1.89, 95% CI = [1.18, 3.03], respectively). Those with a lower adherence to a Mediterranean diet, a higher BMI, a higher consumption of red meat, and a lower consumption of nuts and legumes had an increased risk of ILEF associated with higher levels of essential amino acids. Discussion/Conclusion: Some amino acid species could serve as risk markers for physical function decline in older adults, and healthy diet might attenuate the excess risk of ILEF linked to essential amino acids.

Medicinal leeches (Hirudo verbana Carena, 1820) used in veterinary medicine, human medicine and pharmacology, are currently bred artificially at bio-factories. The technology of leech culture as a component of aquaculture biotechnics is based on the method of accelerated growth of leeches due to intensive feeding, which allows you to get high-quality products in a fairly short time (8-10 months). Nevertheless, the problem of assessing the physiological status of raised individuals upon artificial reproduction remains not fully addressed. The findings we present herein for the first time allow us to suggest that the age-specific amino acid composition of tissues can be used to assess the physiological state and well-being of medicinal leeches in nature and in aquaculture. The aim of the work is to study the age-dependent content of the free amino acids in the tissues of medicinal leeches artificially bred in aquaculture. Studies were conducted in 2012 on the leech (Hirudo verbana Carena, 1820) individuals without signs of diseases which were purchased at the biofactory International Center for Medicinal Leeches (Moscow Province, p. Udelnaya). Leeches were kept in the laboratory in glass vessels with dechlorinated water at 20-22 oC and fed once a month with fresh bovine blood from healthy animals. The experimental specimens of H. verbana was: 5 days (newborn filaments, 0+), 1, 3, 5, 7 and 9 months old, with an average body weight of 0.029, 0.09, 0.25, 0.61, 1.33 and 1.81 g, respectively. Newborn individuals served as a control. The concentration of free amino acids (AA) in the skin and muscle tissue was determined on the analyzer AAA-339M (Mikrotechna, Czech Republic). A total of 105 leech specimens were used, 30 bioassays were prepared, and 660 element determinations were performed. The amino acid composition of the tissues of medicinal leeches H. verbana was represented by 23 AA and their derivatives. The dominant AA with an antioxidant orientation, regardless of age, were glutamine and glutamic acid, alanine, valine, leucine, and glycine, the total content of which was 65 % in filaments, and 58 % in 9-month — old individuals of the total fund AA. In the tissues of medicinal leeches, as well as in warm-blooded animals, the full composition of essential amino acids (EAA) was revealed: threonine, valine, lysine, leucine, isoleucine, histidine, arginine, methionine, phenylalanine, tryptophan. With age, the total concentrations of free amino acids decreased (r = -0.98 at p = 0.000), due to a sharp decrease in the content of arginine (24.0-fold), proline (13.4- fold), isoleucine (12.2- fold), glycine (8.5- fold), lysine (6.8- fold), histidine (6.6-fold), leucine (5.2-fold), ornithine (4.0- fold), glutamic acid and glutamine (3.8-fold), and alanine (2.9-fold). At the age of 5, 7 and 9 months, leeches had a trace content of secondary metabolites: taurine, citrulline and tryptophan (p < 0.001). However, the amino acid balance of nitrogen and protein metabolism was not disturbed, since the ratio of essential / non-essential AА did not change significantly and was 0.60 in newborn filaments, 0.73 — in 9-month-old leeches. It was found that the growth and development of H. verbana was accompanied by a significant decrease in the indicator of maturity (glycine/alanine) from 0.75 (newborn filaments) to 0.25 (9 months). The information available in the literature and the data of our research allow us to put forward the concept of using functional amino acids as biomarkers in the development of the scientific bases of technologies for the industrial breeding of these amphibionts.

Medicinal leeches (Hirudo verbana Carena, 1820) used in veterinary medicine, human medicine and pharmacology, are currently bred artificially at bio-factories. The technology of leech culture as a component of aquaculture biotechnics is based on the method of accelerated growth of leeches due to intensive feeding, which allows you to get high-quality products in a fairly short time (8-10 months). Nevertheless, the problem of assessing the physiological status of raised individuals upon artificial reproduction remains not fully addressed. The findings we present herein for the first time allow us to suggest that the age-specific amino acid composition of tissues can be used to assess the physiological state and well-being of medicinal leeches in nature and in aquaculture. The aim of the work is to study the age-dependent content of the free amino acids in the tissues of medicinal leeches artificially bred in aquaculture. Studies were conducted in 2012 on the leech (Hirudo verbana Carena, 1820) individuals without signs of diseases which were purchased at the biofactory International Center for Medicinal Leeches (Moscow Province, p. Udelnaya). Leeches were kept in the laboratory in glass vessels with dechlorinated water at 20-22 oC and fed once a month with fresh bovine blood from healthy animals. The experimental specimens of H. verbana was: 5 days (newborn filaments, 0+), 1, 3, 5, 7 and 9 months old, with an average body weight of 0.029, 0.09, 0.25, 0.61, 1.33 and 1.81 g, respectively. Newborn individuals served as a control. The concentration of free amino acids (AA) in the skin and muscle tissue was determined on the analyzer AAA-339M (Mikrotechna, Czech Republic). A total of 105 leech specimens were used, 30 bioassays were prepared, and 660 element determinations were performed. The amino acid composition of the tissues of medicinal leeches H. verbana was represented by 23 AA and their derivatives. The dominant AA with an antioxidant orientation, regardless of age, were glutamine and glutamic acid, alanine, valine, leucine, and glycine, the total content of which was 65 % in filaments, and 58 % in 9-month — old individuals of the total fund AA. In the tissues of medicinal leeches, as well as in warm-blooded animals, the full composition of essential amino acids (EAA) was revealed: threonine, valine, lysine, leucine, isoleucine, histidine, arginine, methionine, phenylalanine, tryptophan. With age, the total concentrations of free amino acids decreased (r = -0.98 at p = 0.000), due to a sharp decrease in the content of arginine (24.0-fold), proline (13.4- fold), isoleucine (12.2- fold), glycine (8.5- fold), lysine (6.8- fold), histidine (6.6-fold), leucine (5.2-fold), ornithine (4.0- fold), glutamic acid and glutamine (3.8-fold), and alanine (2.9-fold). At the age of 5, 7 and 9 months, leeches had a trace content of secondary metabolites: taurine, citrulline and tryptophan (p < 0.001). However, the amino acid balance of nitrogen and protein metabolism was not disturbed, since the ratio of essential / non-essential AА did not change significantly and was 0.60 in newborn filaments, 0.73 — in 9-month-old leeches. It was found that the growth and development of H. verbana was accompanied by a significant decrease in the indicator of maturity (glycine/alanine) from 0.75 (newborn filaments) to 0.25 (9 months). The information available in the literature and the data of our research allow us to put forward the concept of using functional amino acids as biomarkers in the development of the scientific bases of technologies for the industrial breeding of these amphibionts.

Background and Aim: Although it is widely known that the total parenteral nutrition (TPN) used frequently in intensive care units has unwanted side effects, there is little known about how it interferes with the amino acid levels taken during the diagnosis of metabolic diseases. Amino acid can lead to inaccurate measurements with mass spectrometry due to its high molecular content of lipids and carbohydrates, which modifies the blood matrix. The purpose of this study was to emphasize the results of amino acid interference, measured with mass spectrometry, in patients administered with TPN. Case Presentation: Incorrect clinical interpretation resulted in the case of a pneumonia patient with false positive and negative blood amino acid levels caused by TPN infusion. The amino acid profile had been requested to rule out an amino acid metabolic defect in the two-year-old boy who arrived at the pediatric clinic complaining of respiratory distress, tachypnea and hypoxemia. He was monitored in the intensive care unit for further investigation. The personnel who had performed phlebotomy also carried out the sampling during the TPN infusion administration. This caused the amino acid results and an incorrect interpretation. The following deviation ratios were detected: phenylalanine 102%, leucine 86%, isoleucine 106%, GABA 200%, citrulline 238%, glutamine 178%, ornithine 216%, 1- methyl-l-histidine 1471%, serine 312%, alanine 163%, glycine 355%, homocitrulline and carnosine 444%. The amino acid blood level measurements taken for diagnosis and screening in suspected metabolic disease may lead to involuntary false low or elevated results in patients administered with TPN. Conclusion: This case demonstrates that TPN solutions affect the reference method of mass spectrometry measurement methods due to the concentration of ingredients. We suggest that inaccurate results can be avoided by carrying out the sampling prior to TPN infusion in patients whose plasma amino acid levels will be measured.

OBJECTIVE: To investigate the intestinal amino acids pathway in depression-like offspring rats induced by maternal separation. METHODS: Sprague-Dawley (SD) female rats were randomly divided into a control group ( n=8) and a maternal separation group ( n=8). After normal delivery, the maternal rats were separated from offsprings for 14 consecutive days and 3 h per day in maternal separation group; while rats in the control group was received no interventions in postpartum. Depression-like behaviors of offspring rats were evaluated using the sucrose preference test, novelty suppressed feeding test, and forced swimming test. Amino acid analyzer was used to detect the changes of amino acid contents in the small intestine, and the expressions of alanine-serine-cysteine transporter 2 (ASCT2), solute carrier superfamily 6 member 19 (B (0)AT1) and L-type amino acid transporter 1(LAT1) were detected by Western blot. RESULTS: The weight of the offspring rats in the maternal separation group was significantly lower than that of the control group at 21 and 28 d ( t=4.925 and 5.766, all P

Recent studies on the regulatory role of amino acids in cell metabolism have focused on the functional significance of proline degradation. The process is catalysed by proline dehydrogenase/proline oxidase (PRODH/POX), a mitochondrial flavin-dependent enzyme converting proline into ∆1-pyrroline-5-carboxylate (P5C). During this process, electrons are transferred to electron transport chain producing ATP for survival or they directly reduce oxygen, producing reactive oxygen species (ROS) inducing apoptosis/autophagy. However, the mechanism for switching survival/apoptosis mode is unknown. Although PRODH/POX activity and energetic metabolism were suggested as an underlying mechanism for the survival/apoptosis switch, proline availability for this enzyme is also important. Proline availability is regulated by prolidase (proline supporting enzyme), collagen biosynthesis (proline utilizing process) and proline synthesis from glutamine, glutamate, α-ketoglutarate (α-KG) and ornithine. Proline availability is dependent on the rate of glycolysis, TCA and urea cycles, proline metabolism, collagen biosynthesis and its degradation. It is well established that proline synthesis enzymes, P5C synthetase and P5C reductase as well as collagen prolyl hydroxylases are up-regulated in most of cancer types and control rates of collagen biosynthesis. Up-regulation of collagen prolyl hydroxylase and its exhaustion of ascorbate and α-KG may compete with DNA and histone demethylases (that require the same cofactors) to influence metabolic epigenetics. This knowledge led us to hypothesize that up-regulation of prolidase and PRODH/POX with inhibition of collagen biosynthesis may represent potential pharmacotherapeutic approach to induce apoptosis or autophagic death in cancer cells. These aspects of proline metabolism are discussed in the review as an approach to understand complex regulatory mechanisms driving PRODH/POX-dependent apoptosis/survival.

Nature Communications 12(1), 2176 (2021). doi:10.1038/s41467-021-22320-y, The hexosamine pathway (HP) is a key anabolic pathway whose product uridine 5���-diphospho-N-acetyl-D-glucosamine (UDP-GlcNAc) is an essential precursor for glycosylation processes in mammals. It modulates the ER stress response and HP activation extends lifespan in Caenorhabditis elegans. The highly conserved glutamine fructose-6-phosphate amidotransferase 1 (GFAT-1) is the rate-limiting HP enzyme. GFAT-1 activity is modulated by UDP-GlcNAc feedback inhibition and via phosphorylation by protein kinase A (PKA). Molecular consequences of GFAT-1 phosphorylation, however, remain poorly understood. Here, we identify the GFAT-1 R203H substitution that elevates UDP-GlcNAc levels in C. elegans. In human GFAT-1, the R203H substitution interferes with UDP-GlcNAc inhibition and with PKA-mediated Ser205 phosphorylation. Our data indicate that phosphorylation affects the interactions of the two GFAT-1 domains to control catalytic activity. Notably, Ser205 phosphorylation has two discernible effects: it lowers baseline GFAT-1 activity and abolishes UDP-GlcNAc feedback inhibition. PKA controls the HP by uncoupling the metabolic feedback loop of GFAT-1., Published by Nature Publishing Group UK, [London]

Mass attenuation coefficients, effective atomic numbers, electron densities and energy absorption and exposure buildup factors for the non-essential and conditionally non-essential amino acids including alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine have been acquired using the latest evaluated photoatomic library of EPICS2017. The library was used by constructing an interpolation script that calculates for all photon attenuation parameters. Comparisons were made using alternative Monte Carlo simulation results for 15 energy points from 59.5 to 1333 keV, and in contrast with experimental works in literature. Good agreements for the mass attenuation coefficients were observed between EPICS2017-based values compared with Monte Carlo code and experimental results. Similar trends for the effective atomic numbers and electron densities were observed from EPICS2017 interpolation and from results found in literature. Conversely, buildup factors acquired by Geometric-Progression fitting parameters were reported in this work preliminarily for most of these biomolecules at different penetration depths. Overall, cysteine showed the most significant deviation among the other non-essential amino acids due to the presence of sulfur in its molecular structure.

The metabolic change of tumor cells is an extremely complicated process that involves the intersection and integration of various signal pathways. Compared with normal tissues, cancer cells show distinguished metabolic characteristics called metabolic reprogramming, which has been considered as a sign of cancer occurrence. With the deepening of tumor research in recent years, people gradually found that amino acid metabolism played crucial roles in cancer progression. Long non-coding RNAs (lncRNAs), which are implicated in many important biological processes, were firstly discovered dysregulating in cancer tissues and participating in extensive regulation of tumorigenesis. This review focuses on the reprogramming of amino acid metabolism in cancers and how lncRNAs participate in the regulatory network by interacting with other macromolecular substances. Understanding the functions of lncRNA in amino acid reprogramming in tumors might provide a new vision on the mechanisms of tumorigenesis and the development of new approaches for cancer therapy.

The Japanese quince (Chaenomeles japonica) seeds (JQS) are generated in large amounts as a by-product in considerable quantities during industrial quince fruit processing. Due to economic, environmental, and nutritional reasons, the utilization of JQS as a protein source seems to be highly justified. Therefore, three cultivars were studied, 'Rasa', 'Rondo', and 'Darius' of JQS as a protein source during three harvesting years. The total protein content in JQS determined by the Kjeldahl method amounted from 24.6 to 33.2% and was significantly affected (p ≤ 0.05) by the cultivar and harvesting year. The protein isolation was most effective in the pH range of 6-9, and their profile was mainly characterized by a molecular weight of 54.1-57.7 kDa and 70.0-77.6 kDa. The amino acids profile of JQS turned out to be valuable from a nutritional point of view due to the relatively high content of essential and relatively essential amino acids such as histidine (6-9%), leucine (11-12%), lysine (10-16%), phenylalanine (12-16%), glutamine/glutamic acid (7-15%), and tyrosine (9-13%). The initial analysis of JQS indicates that they can be a good source of proteins characterized by a favorable amino acid profile.

NMR offers the unique potential to holistically screen hundreds of metabolites and has already proved to be a powerful technique able to provide a global picture of a wide range of metabolic processes underlying complex and multifactorial diseases, such as neurodegenerative and neurodevelopmental diseases. The aim of this study was to apply an NMR-based metabolomics approach to explore brain metabolic changes in both male and female rats induced by prenatal exposure to two chemicals associated with autism disorders-the organophosphorus pesticide chlorpyrifos (CPF) and the antiepileptic drug valproic acid (VPA)-at different postnatal ages. Depending on the age and on the brain region (hippocampus and cerebellum), several metabolites were shown to be significantly affected by exposure to both compounds. The evaluation of the spectral profiles revealed that the nervous-system-specific metabolite N-acetylaspartate (NAA), amino acid neurotransmitters (e.g., glutamate, glutamine, GABA, glycine), pyroglutamic acid, unsaturated fatty acids, and choline-based compounds are discriminant biomarkers. Additionally, metabolic changes varied as a function of age, but importantly not of sex.

Restriction of the sulfur amino acids methionine and cysteine has recently been proposed as potential adjuvant therapy in cancer. While cysteine depletion has been associated with ferroptotic cell death, methionine depletion has not. We hypothesized that comparing the response of melanoma cell lines to depletion of the amino acids methionine and cysteine would give us insight into the critical role in cancer of these two closely related amino acids. We analyzed the response to three conditions: methionine depletion, methionine replacement with homocysteine, and cysteine depletion. In cancer cells, the transcription factor ATF4 was induced by all three tested conditions. The replacement of methionine with homocysteine produced a strong ferroptotic gene signature. We also detected an activation of the NRF2 antioxidant pathway by both methionine and cysteine depletion. Total glutathione levels were decreased by 42% in melanoma cells grown without methionine, and by 95% in cells grown without cysteine. Lipid peroxidation was increased in cells grown without cysteine, but not in cells grown without methionine. Despite the large degree of overlap in gene expression between methionine and cysteine depletion, methionine depletion and replacement of methionine with homocysteine was associated with apoptosis while cysteine depletion was associated with ferroptosis. Glutamine depletion produced comparable gene expression patterns and was associated with a 28% decrease in glutathione. Apoptosis was detected in these cells. In this experiment, a strong ATF4-driven ferroptotic gene signature was insufficient to induce ferroptosis without a concomitant profound decrease in glutathione levels.

Comparative genomic analysis was performed on eight species of lactic acid bacteria (LAB)-Lactococcus (L.) lactis, Lactobacillus (Lb.) plantarum, Lb. casei, Lb. brevis, Leuconostoc (Leu.) mesenteroides, Lb. fermentum, Lb. buchneri, and Lb. curvatus-to assess their glutamic acid production pathways. Glutamic acid is important for umami taste in foods. The only genes for glutamic acid production identified in the eight LAB were for conversion from glutamine in L. lactis and Leu. mesenteroides, and from glucose via citrate in L. lactis. Thus, L. lactis was considered to be potentially the best of the species for glutamic acid production. By biochemical analyses, L. lactis HY7803 was selected for glutamic acid production from among 17 L. lactis strains. Strain HY7803 produced 83.16 pmol/μl glutamic acid from glucose, and exogenous supplementation of citrate increased this to 108.42 pmol/μl. Including glutamic acid, strain HY7803 produced more of 10 free amino acids than L. lactis reference strains IL1403 and ATCC 7962 in the presence of exogenous citrate. The differences in the amino acid profiles of the strains were illuminated by principal component analysis. Our results indicate that L. lactis HY7803 may be a good starter strain for glutamic acid production.

Amino acid substitutions within the conserved polypeptide sequence of the insect olfactory receptor co-receptor (Orco) have been demonstrated to influence its pharmacological properties. By sequence analysis and phylogenetic investigation, in the Lepidopteran subgroup Ditrysia we identified a fixed substitution in the intracellular loop-3 (ICL-3) of a conserved histidine to glutamine. By means of HEK293 cells as a heterologous system, we functionally expressed Orco from the Ditrysian model Cydia pomonella (CpomOrco) and compared its functional properties with a site-directed mutagenized version where this ICL-3-glutamine was reverted to histidine (CpomOrcoQ417H). The mutagenized CpomOrcoQ417H displayed decreased responsiveness to VUAA1 and reduced response efficacy to an odorant agonist was observed, when co-transfected with the respective OR subunit. Evidence of reduced responsiveness and sensitivity to ligands for the mutagenized Orco suggest the fixed glutamine substitution to be optimized for functionality of the cation channel within Ditrysia. In addition, contrary to the wild type, the mutagenized CpomOrcoQ417H preserved characteristics of VUAA-binding when physiologic conditions turned to acidic. Taken together, our findings provide further evidence of the importance of ICL-3 in forming basic functional properties of insect Orco- and Orco/OR-channels, and suggest involvement of ICL-3 in the potential functional adaptation of Ditrysian Orcos to acidified extra-/intracellular environment.

Amino acid (AA) concentrations are influenced by both exogenous (e.g. diet, lifestyle) and endogenous factors (e.g. genetic, transcriptomic, epigenetic, and metabolomic). Fasting plasma AA profiles in adulthood are predictive of diabetes risk over periods of up to 12 years. Data on AA profiles in cross-generational cohorts, including individuals from shared gene-environment settings are scarce, but would allow the identification of the contribution of heritable and environmental factors characterising the levels of circulating AAs. This study aimed to investigate parent–child (familial dyad) concordance, absolute differences between generations- (children versus adults), age- (in adults: 28–71 years), and sex-dependent differences in plasma AA concentrations. Plasma AA concentrations were measured by UHPLC/MS–MS in 1166 children [mean (SD) age 11 (0.5) years, 51% female] and 1324 of their parents [44 (5.1) years, 87% female]. AA concentrations were variably concordant between parents and their children (5–41% of variability explained). Most AA concentrations were higher in adults than children, except for the non-essential AAs arginine, aspartic acid, glutamine, hydroxy-proline, proline, and serine. Male adults and children typically had higher AA concentrations than females. The exceptions were alanine, glutamine, glycine, hydroxy-proline, serine, and threonine in girls; and glycine and serine in women. Age, sex, and shared familial factors are important determinants of plasma AA concentrations.

Wild soybean (Glycine soja) is a valuable genetic resource for soybean improvement. Seed composition profiles provide beneficial information for the effective conservation and utilization of wild soybeans. Therefore, this study aimed to assess the variation in free amino acid abundance in the seeds of wild soybean germplasm collected in Japan. The free amino acid content in the seeds from 316 accessions of wild soybean ranged from 0.965 to 5.987 mg/g seed dry weight (DW), representing a 6.2-fold difference. Three amino acids had the highest coefficient of variation (CV): asparagine (1.15), histidine (0.95) and glutamine (0.94). Arginine (0.775 mg/g DW) was the predominant amino acid in wild soybean seeds, whereas the least abundant seed amino acid was glutamine (0.008 mg/g DW). A correlation network revealed significant positive relationships among most amino acids. Wild soybean seeds from different regions of origin had significantly different levels of several amino acids. In addition, a significant correlation between latitude and longitude of the collection sites and the total free amino acid content of seeds was observed. Our study reports diverse phenotypic data on the free amino acid content in seeds of wild soybean resources collected from throughout Japan. This information will be useful in conservation programmes for Japanese wild soybean and for the selection of accessions with favourable characteristics in future legume crop improvement efforts.

Background: Carbon (C) and nitrogen (N) assimilate availability and their ratios are crucial for maize grain production and N‐use efficiency. Aim: Our aim was to give a mechanistic understanding of yield formation regulated by assimilate C:N balance during both early ear development and rapid grain filling. Methods: Maize was grown under field conditions with 0, 200, and 300 kg N ha⁻¹ (referred to as N0, N200, and N300, respectively). Ear growth, grain yield, and dynamics of total C and N accumulation in ear leaves, cobs, and developing kernels (apical and basal proportions separated from the longitudinally middle of ear) were investigated, as well as the non‐structural carbohydrates and free amino acids. Results: Compared to N‐sufficient plants, low‐N plants contained 16% to 70% less N and 8% to 50% less C in the developing kernels, causing 43% to 52% yield losses, which indicated that low‐N kernels received less amino acid per unit sugar from the maternal plants. This was supported by lower concentrations of the main N transport molecules (glutamine and asparagine) in ear leaves at silking and 21 days after silking (DAS) coupled with the larger amounts of C accumulated as starch under N deficient compared to adequate N supply. Nitrogen treatment did not influence the concentrations of total free amino acids and soluble protein in the cob, neither at silking nor 21 DAS, but it did influence cob free amino acid composition. Compared to the adequate N supply, low‐N plants contained 75% and 57% less glutamine and asparagine in apical kernels at silking, as well as 36% and 31% less in basal kernels. Free amino acid concentrations in both cob and kernels were less responsive to N treatments at 21 DAS than at silking, especially in the basal ear halves. Conclusion: Maize grain production under low‐N environment can be more attributed to the balance in assimilate composition, particularly the amino acid profile, than the C‐assimilate availability for ear growth and development.

A virus minimally contains a nucleic acid genome packaged by a protein coat. The genome and capsid together are known as the nucleocapsid, which has an envelope containing a lipid bilayer (mainly phospholipids) originating from host cell membranes. The viral envelope has transmembrane proteins that are usually glycoproteins. The proteins in the envelope bind to host cell receptors, promoting membrane fusion and viral entry into the cell. Virus-infected host cells exhibit marked increases in glutamine utilization and metabolism. Glutamine metabolism generates ATP and precursors for the synthesis of macromolecules to assemble progeny viruses. Some compounds derived from glutamine are used in the synthesis of purines and pyrimidines. These latter compounds are precursors for the synthesis of nucleotides. Inhibitors of glutamine transport and metabolism are potential candidate antiviral drugs. Glutamine is also an essential nutrient for the functions of leukocytes (lymphocyte, macrophage, and neutrophil), including those in virus-infected patients. The increased glutamine requirement for immune cell functions occurs concomitantly with the high glutamine utilization by host cells in virus-infected patients. The development of antiviral drugs that target glutamine metabolism must then be specifically directed at virus-infected host cells to avoid negative effects on immune functions. Therefore, the aim of this review was to describe the landscape of cellular glutamine metabolism to search for potential candidates to inhibit glutamine transport or glutamine metabolism.

l-Theanine is a characteristic amino acid in tea with various effects including antioxidant and anti-inflammatory effects. Previously, most studies had reported that l-theanine regulates the immune function in vivo by inhibiting the expression of the inflammatory factors, but how l-theanine regulates the inflammatory factors' pathway is not known. In this study, we innovatively found the binding target of l-theanine in vivo-cannabinoid receptor 1, and demonstrated that l-theanine regulated the immune function and glutamine metabolism by competitively binding cannabinoid receptor 1. Mechanistically, l-theanine competitively binds cannabinoid receptor 1, leading to inhibition of cannabinoid receptor 1 activity, and regulates glutamine metabolism and immune function in normal and E44813-stressed rats. In normal rats, l-theanine inhibits ERK1/2 phosphorylation through Gβy by antagonizing cannabinoid receptor 1, thus affecting GS expression. From the point of view of immune signaling, after LTA antagonizes the activity of cannabinoid receptor 1, it relieves the inhibition of cannabinoid receptor 1 on COX-2 expression, downregulates Pdcd4 expression and NFκB, and ultimately enhances the expression of the anti-inflammatory factor IL-10. In E44813-stressed rats, l-theanine promotes the nuclear translocation of p-ERK1/2 by inhibiting the activity of cannabinoid receptor 1, and finally acts on GS. At the same time, it decreases the expression of the pro-inflammatory factor TNF-α and increases the expression of the anti-inflammatory factor IL-10 in stressed rats through the COX2-Pdcd4-NFκB-IL10 and TNFα pathways. In summary, these results demonstrate that l-theanine regulates glutamine metabolism and immune function by competitively binding to cannabinoid receptor 1.

Asparagine synthetase (ASNS) and CTP synthase (CTPS) are two metabolic enzymes that catalyze the biosynthesis of asparagine and CTP, respectively. Both CTPS and ASNS have been identified to form cytoophidia in Saccharomyces cerevisiae. Glutamine is a common substrate for both these enzymes, and they play an important role in glutamine homeostasis. Here, we find that the ASNS cytoophidia are shorter than the CTPS cytoophidia, and that disruption of ASNS shortens the length of CTPS cytoophidia. However, the deletion of CTPS has no effect on the formation and length of ASNS cytoophidia, or on the ASNS protein level. We also find that Asn1 overexpression induces the formation of a multi-dot structure in diauxic phase which suggests that the increased protein level may trigger cytoophidia formation. Collectively, our results reveal a connection between ASNS cytoophidia and CTPS cytoophidia.

The amino acid composition and activity of the enzymes of placental amino acid metabolism were studied in guinea pigs (Cavia porcellus) and rhesus macaques (Macaca mulatta) which have a hemochorial type of placenta, similar to that in humans. The study also included women with uncomplicated pregnancy and delivery at full term (39–40 weeks). It was established that the fetal (chorionic) part of the placenta is characterized by the highest level of free and bound amino acids and maximum activity of enzymes related to amino acid metabolism (aminotransferases, deaminases, amino synthetases) in all tissues studied. A high level of dicarboxylic amino acids and glutamine is also common to the placenta of guinea pigs, monkeys and humans. Along with common traits, placental amino acid metabolism in different animal species and humans reveal some differences depending on the evolutionary features of the organ’s development and the specificity of the existing maternal-fetal relationships. Interspecies differences between the analogous parts of the placenta concern individual amino acids, the level of most of which in the placenta of rodents exceeds the same indices in primates. The relevant differences between human and apish placentas are less pronounced. The guinea pig placenta is different from those in humans and monkeys in the mode of non-covalent binding of amino acids to biopolymers, which modifies the state of the acceptor protein groups. Analogous afterbirth tissues in different animal species and humans differ in the activity of the enzymes of amino acid metabolism. There is a close correlation between the level of free amino acids and the indices of enzyme activity, indicating their important role in the formation of the placental amino acid pool.

Background Topotecan is an anti-cancer chemotherapy drug with common side effects, including hepatotoxicity. In this study, we aim to investigate the mechanisms of topotecan-induced hepatocellular injury beyond conventional DNA damage. Materials and methods Methyl Thiazolyl Tetrazolium (MTT) assay was used to detect the inhibitory effect of topotecan on cell proliferation. Western blot was used to detect protein expression. Flow cytometry assay was performed to determine apoptosis rate under topotecan treatment. ASCT2 overexpression was addressed using adenovirus vector. qRT-PCR and western blot assay were used to detect the expression of ASCT2. Glutamine uptake, intracellular glutathione (GSH) and reactive oxygen species (ROS) level were detected by glutamine detection kit, GSH detection kit and ROS detection kit respectively. Results MTT results showed that topotecan had an inhibitory effect on cell proliferation and induced apoptosis in both L02 and HepG2 cell lines. Topotecan inhibited the expression of glutamine transporter ASCT2 and the uptake of glutamine in both L02 and HepG2 cell lines. The uptake of glutamine and the GSH level was increased in both L02 and HepG2 cell lines after ASCT2 overexpression. The ROS level was inhibited by ASCT2 overexpression upon topotecan treatment in both L02 and HepG2 cell lines. Topotecan-induced hepatocellular apoptosis and proliferation inhibition were attenuated by ASCT2 overexpression in both L02 and HepG2 cell lines. Conclusion Topotecan-induced hepatocytes death is dependent on ASCT2 down-regulation, which causes oxidative stress via inhibiting GSH production.

The amino acid composition and activity of the enzymes of the amino acid metabolism of placenta were studied. The objects of the study were guinea pigs (Cavia porcellus) and rhesus macaques (Macaca mulatta), which have a hemochoric placenta type, similar to humans. The study also included women with uncomplicated pregnancy and delivery on time (39-40 weeks). It was found that in the all tissues studied, the fetal part of the placenta is characterized by the highest content of free and bound amino acids. In the fetal part of the placenta, the maximal activity of amino acid metabolism enzymes (aminotransferases, deaminases, amino synthetases) was also found. Common to the placenta of guinea pigs, monkeys and humans is also a high level of dicarboxylic amino acids and glutamine. Along with the common features in the amino acid metabolism of the placenta of different species of animals and humans, some differences were revealed due to the evolutionary features of the development of the organ, the specifics of the existing maternal-fetal relationships. Interspecies differences of the same parts of the placenta relate to individual amino acids, the majority of which in the placenta of rodents exceeds similar indicators in primates. Between the placentas of humans and monkeys, the differences in the studied biochemical parameters are less pronounced. Another difference between guinea pig placenta and human and monkey placenta is the unequal non-covalent binding of amino acids to biopolymers, which modifies the state of the acceptor groups of proteins. Similar tissues of the afterbirth of different species of animals and humans differ in the activity of amino acid metabolism enzymes. There is a close correlation between the content of free amino acids and indicators of enzyme activity, showing their important role in the formation of the placental amino acid fund.