Asparagine Levels Research Articles

Effects of blanching treatments on acrylamide, asparagine, reducing sugars and colour in potato chips.

This study aimed to determine the effect of combinations of blanching parameters, including blanching temperatures ranging from 65 to 85°C and duration times ranging from 2 to 10min, on reducing sugars, asparagine, acrylamide, and color levels of fried potato chips. Response surface methodology was used to develop response surface equations to estimate these effects. These latter were evaluated before and after a 3-month storage period of potato tubers at 10°C. It was found that certain blanching parameters resulted in optimal maximum reductions of 64.2, 49.8, and 61.3% for reducing sugar, asparagine, and acrylamide, respectively. Analysis of variance (ANOVA) determined that blanching time had a more significant impact than blanching temperature. The blanching time that resulted in maximum reductions of asparagine, reducing sugars-and ultimately acrylamide-were in the range of 8.8-9.7min at 68.7-75.0°C. ANOVA also determined that after the 3-month storage period of potato tubers, variations in blanching time and temperature did not result in any significant differences in acrylamide formation in fried chips. Blanching consistently improved the appearance of the fried chip products, indicated by increases in L* value and decreases in a* values. The relationship between acrylamide formation and a* value was linear (R2 = 0.839), while the relationship between acrylamide formation and L* value was not (R2 = 0.375).

Metabolomic Profiles Reveal Potential Factors that Correlate with Lactation Performance in Sow Milk

Sow milk contains necessary nutrients for piglets; however, the relationship between the levels of metabolites in sow milk and lactation performance has not been thoroughly elucidated to date. In this study, we analysed the metabolites in sow milk from Yorkshire sows with high lactation (HL) or low lactation (LL) performance; these categories were assigned based on the weight gain of piglets during the entire lactation period (D1 to D21). The concentration of milk fat in the colostrum tended to be higher in the HL group (P = 0.05), the level of mannitol was significantly lower in the HL group (P < 0.05) and the level of glucuronic acid lactone was significantly higher in the HL group (P < 0.05) compared to those in LL group. In mature milk, the levels of lactose, creatine, glutamine, glutamate, 4-hydroxyproline, alanine, asparagine, and glycine were significantly higher (P < 0.05) in the HL group than those in LL group. The level of fatty acids showed no significant difference between the two groups in both the colostrum and mature milk. This study suggested that lactation performance may be associated with the levels of lactose and several amino acids in sow milk, and these results can be used to develop new feed additives to improve lactation performance in sows.

Abstract 3521: Glutamine metabolic inhibition synergizes with L-asparaginase in MYCN-amplified neuroblastoma

Abstract Neuroblastoma is the most common extracranial solid tumor in children. Though it accounts for about 10% of pediatric cancers, it is disproportionately responsible for 15% of pediatric cancer deaths. MYCN is amplified in 20% of neuroblastomas and correlates with adverse outcome. MYCN is involved in the maintenance of cancer stem cells, as well as in driving tumor cell growth, proliferation and tumorigenesis. Attempts to inhibit MYCN directly have been largely unsuccessful. MYCN is known to drive tumor cell reliance on glutamine for cellular metabolism. 6-Diazo-5-oxo-L-norleucine (DON) is a well-characterized glutamine analogue that inhibits glutamine metabolism by irreversibly inactivating multiple glutamine-utilizing enzymes. DON was well tolerated in a previous phase I clinical trial in pediatric patients, but it has never been systematically tested in neuroblastoma patients. We show that MYCN-amplification confers sensitivity to DON therapy in in vitro models of neuroblastoma, and that DON administered by intraperitoneal injection twice weekly significantly reduces flank tumor volume in orthotopic mouse models of MYCN-amplified neuroblastoma (mean tumor volume 1715 mm3 vs. 207 mm3 in control animals, p-value = 0.00017 by t-test). We have also developed an orally bioavailable DON prodrug, JHU083, and we found that this drug administered orally three times weekly was similarly able to suppress neuroblastoma tumor growth in mice (mean tumor volume 1,115 mm3 vs. 217 mm3 in control animals, p-value = 0.0000088 by t-test). In metabolic flux experiments, tracing glutamine and glucose donation of 13C and 15N via liquid chromatography/mass spectrometry, DON prevents asparagine synthesis, depleting intracellular asparagine levels by 40% compared to control treated cells (p-value = 0.006). DON combined with L-asparaginase synergistically inhibits growth of MYCN-amplified neuroblastoma cell lines (CI = 0.25 by the Chou-Talalay method, indicating strong synergy; p-value = 0.00011). We conclude that DON depletes cellular pools of asparagine, and combination therapy with DON and L-asparaginase synergistically inhibits the growth of MYCN-amplified neuroblastoma. These studies provide the preclinical justification for potential clinical trials for the use of DON or DON prodrugs in combination with L-asparaginase as new therapeutic options for patients with MYCN-amplified neuroblastoma. Citation Format: Micah J. Maxwell, Brad Poore, Allison Hanaford, Jesse Alt, Rana Rais, Barbara S. Slusher, Charles G. Eberhart, Eric H. Raabe. Glutamine metabolic inhibition synergizes with L-asparaginase in MYCN-amplified neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3521.

2,4-dichlorophenoxyacetic acid-induced oxidative stress: Metabolome and membrane modifications in Umbelopsis isabellina, a herbicide degrader.

The study reports the response to herbicide of the 2,4-dichlorophenoxyacetic acid (2,4-D)–degrading fungal strain Umbelopsis isabellina. A comparative analysis covered 41 free amino acids as well as 140 lipid species of fatty acids, phospholipids, acylglycerols, sphingolipids, and sterols. 2,4-D presence led to a decrease in fungal catalase activity, associated with a higher amount of thiobarbituric acid-reactive substances (TBARS). Damage to cells treated with the herbicide resulted in increased membrane permeability and decreased membrane fluidity. Detailed lipidomic profiling showed changes in the fatty acids composition such as an increase in the level of linoleic acid (C18:2). Moreover, an increase in the phosphatidylethanolamine/phosphatidylcholine ratio was observed. Analysis of fungal lipid profiles revealed that the presence of 2,4-D was accompanied by the accumulation of triacylglycerols, a decrease in ergosterol content, and a considerable rise in the level of sphingolipid ceramides. In the exponential phase of growth, increased levels of leucine, glycine, serine, asparagine, and hydroxyproline were found. The results obtained in our study confirmed that in the cultures of U. isabellina oxidative stress was caused by 2,4-D. The herbicide itself forced changes not only to membrane lipids but also to neutral lipids and amino acids, as the difference of tested compounds profiles between 2,4-D—containing and control samples was consequently lower as the pesticide degradation progressed. The presented findings may have a significant impact on the basic understanding of 2,4-D biodegradation and may be applied for process optimization on metabolomic and lipidomic levels.

Impact in Plasma Metabolome as Effect of Lifestyle Intervention for Weight-Loss Reveals Metabolic Benefits in Metabolically Healthy Obese Women.

Little is known regarding metabolic benefits of weight loss (WL) on the metabolically healthy obese (MHO) patients. We aimed to examine the impact of a lifestyle weight loss (LWL) treatment on the plasma metabolomic profile in MHO individuals. Plasma samples from 57 MHO women allocated to an intensive LWL treatment group (TG, hypocaloric Mediterranean diet and regular physical activity, n = 30) or to a control group (CG, general recommendations of a healthy diet and physical activity, n = 27) were analyzed using an untargeted 1H NMR metabolomics approach at baseline, after 3 months (intervention), and 12 months (follow-up). The impact of the LWL intervention on plasma metabolome was statistically significant at 3 months but not at follow-up and included higher levels of formate and phosphocreatine and lower levels of LDL/VLDL (signals) and trimethylamine in the TG. These metabolites were also correlated with WL. Higher myo-inositol, methylguanidine, and 3-hydroxybutyrate, and lower proline, were also found in the TG; higher levels of hippurate and asparagine, and lower levels of 2-hydroxybutyrate and creatine, were associated with WL. The current findings suggest that an intensive LWL treatment, and the consequent WL, leads to an improved plasma metabolic profile in MHO women through its impact on energy, amino acid, lipoprotein, and microbial metabolism.

Pharmacodynamic characterization of eryaspase (L-asparaginase encapsulated in red blood cells) in combination with chemotherapy in a phase 2/3 trial in patients with relapsed acute lymphoblastic leukemia (NCT01518517).

7049Background: L-asparaginase (ASNase) is a key drug in the treatment of ALL. ASNase therapy aims to lower serum asparagine (ASN) levels, but no critical minimum value for efficacy has yet been es...

Altered Asparagine and Glutamate Homeostasis Precede Coronary Artery Disease and Type 2 Diabetes.

Type 2 diabetes mellitus (T2DM) is accompanied by an increased risk for coronary artery disease (CAD), but the overlapping metabolic disturbances preceding both diseases are insufficiently described. We hypothesized that alterations in metabolism occur years before clinical manifestation of T2DM and CAD and that these alterations are reflected in the plasma metabolome. We thus aimed to identify plasma metabolites that predict future T2DM and CAD. Through use of targeted liquid chromatography-mass spectrometry, 35 plasma metabolites (amino acid metabolites and acylcarnitines) were quantified in 1049 individuals without CAD and diabetes, drawn from a population sample of 5386 in the Malmö Preventive Project (mean age, 69.5 years; 31% women). The sample included 204 individuals who developed T2DM, 384 who developed CAD, and 496 who remained T2DM and CAD free during a mean follow-up of 6.1 years. In total, 16 metabolites were significantly associated with risk for developing T2DM according to logistic regression models. Glutamate (OR, 1.96; P = 5.4e-12) was the most strongly associated metabolite, followed by increased levels of branched-chain amino acids. Incident CAD was predicted by three metabolites: glutamate (OR, 1.28; P = 6.6e-4), histidine (OR, 0.76; P = 5.1e-4), and asparagine (OR, 0.80; P = 2.2e-3). Glutamate (OR, 1.48; P = 1.6e-8) and asparagine (OR, 0.75; P = 1.8e-5) were both associated with a composite endpoint of developing T2DM or CAD. Several plasma metabolites were associated with incidence of T2DM and CAD; elevated glutamate and reduced asparagine levels were associated with both diseases. We thus discovered associations that might help shed additional light on why T2DM and CAD commonly co-occur.

Metabolomic Analysis of Overactive Bladder in Male Patients: Identification of Potential Metabolite Biomarkers

To identify metabolites that are associated with an overactive bladder (OAB) using metabolomics. A total of 58 male patients without apparent neurologic disease completed 24-hour bladder diaries of their micturition behavior and International Prostate Symptom Score (IPSS) for the assessment of micturition behavior and lower urinary tract symptoms. Urgency was defined as an IPSS urgency score of ≥2 (OAB group), and patients with IPSS urgency scores of ≤1 belonged to the control group. A comprehensive study of plasma metabolites was also conducted using capillary electrophoresis time-of-flight mass spectrometry. Metabolite levels were compared between the control and OAB groups using the Mann-Whitney U test. Potential metabolite biomarkers were selected using multivariate logistic regression analysis. Of the 58 subjects, the control and OAB groups consisted of 32 and 26 male patients, respectively. Nocturnal urinary volume, 24-hour micturition frequency, nocturnal micturition frequency, and the nocturia index were significantly higher in the OAB group. Metabolomic analysis revealed 60 metabolites in the subjects' plasma. The levels of 11 metabolites differed between the control and OAB groups. Multivariate analysis showed that an increased glutamate level and reduced arginine, glutamine, and inosine monophosphate levels are significantly associated with OAB in male patients. Reduced levels of asparagine and hydroxyproline could also be associated with OAB. Urgency is associated with abnormal metabolism. Analyses of amino acid profiles might aid the search for new treatment targets for OAB.

Phloem nutrition of detached cabbage leaves varies with leaf age and influences performance of the green peach aphid, Myzus persicae

AbstractAphids mainly feed on the phloem sap of host plants and their performance is determined by nutrients and defensive metabolites in their diet. Plant leaves are connected with each other by phloem bundles and thus plant resistance to aphids may require the leaves be intact. Excised plant tissues usually have different resistance levels to aphids compared with intact plants; however, the underlying mechanism remains unknown. In this study, we found that the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), strongly preferred detached young cabbage leaves, but exhibited a poorer performance on these leaves than on detached mature leaves. Compared with other leaves, detached young leaves contained higher levels of arginine, asparagine, methionine, and valine, whereas young leaves showed a very poor phloem nutritional quality, reflected by significantly lower amino acid concentrations in aphid honeydew. In contrast, honeydew produced by aphids feeding on detached old leaves and mature leaves contained higher total amino acid concentrations and lower total sugar contents, indicating higher phloem nutritional quality. Because honeydew excretion rates were comparable among aphids feeding on different leaves, the poorer performance of aphids on detached young leaves may be explained by the lower nutritional quality and food quantity that aphids had ingested. On the other hand, levels of most glucosinolates were the highest in detached young leaves and the lowest in detached old leaves, suggesting that the higher attractiveness of young leaves for aphids is not likely determined by glucosinolates. These results suggest that total amino acids that aphids can ingest play a key role in determining aphid performance. Future studies on plant resistance to aphids should focus on both phloem nutritional quality and aphid feeding rate, and should avoid using excised leaves or detached plant tissues.

Translational and HIF11-Dependent Metabolic Reprograming Underpin Oncometabolome Plasticity and Synergy Between Oncogenic Kinase Inhibitors and Biguanides

There is heightened interest to devise therapies that target the oncometabolome. We show that kinase inhibitors (KIs) and biguanides synergistically target melanoma, leukemia, and breast, colon and renal cancer cells, but not non-transformed cells. Metabolic profiling confirmed opposing effects of KIs and biguanides on glycolysis, but this was insufficient to explain the observed synergy between the drugs. Rather, we define a critical role for the synthesis of non-essential amino acids (NEAA) aspartate, asparagine and serine as well as reductive glutamine metabolism, in determining the sensitivity of cancer cells to KI - biguanide combinations. The mTORC1/4E-BP axis regulates aspartate, asparagine and serine synthesis by modulating translation of mRNAs encoding PC, ASNS, PHGDH and PSAT1. Ablation of 4E-BP1 and 2 results in a dramatic increase in serine, aspartate and asparagine levels and a substantial decrease in sensitivity of breast cancer and melanoma cells to KI - biguanide combinations. In turn, efficacy of KI - biguanide combinations is impeded by HIF1α and sustained reductive glutamine metabolism. These findings identify hitherto unappreciated translational reprograming of NEAA synthesis and HIF1α-dependent stimulation of reductive glutamine metabolism as critical metabolic vulnerabilities of cancer that underpin synergy between KIs and biguanides.

Specific Profiles Of Circulating Mediators Characterize Older Persons With Physical Frailty And Sarcopenia

Chronic inflammation, changes in body composition, muscle loss (sarcopenia) and decreasing homeostatic reserve (frailty) are hallmarks of aging. Several circulating inflammatory markers have been associated with these age‐related conditions. However, a gold standard biomarker able to predict functional impairment in older adults is currently unavailable. Muscle is crucial for several metabolic processes, including protein/aminoacid metabolism. Perturbations in protein/aminoacid metabolism may play also a role in the development of physical frailty and sarcopenia (PF&amp;S). The simultaneous analysis of an array of circulating aminoacid/metabolites and their relationship with inflammatory mediators may help gain insights in the pathophysiology of PF&amp;S.To this aim, we analyzed the profile of circulating inflammatory mediators and amino acids in older people with and without PF&amp;S.More than five hundred persons aged 70+ years were screened. Of these, sixty (20 men and 40 women; mean age 76.9±4.8 years) were diagnosed with PF&amp;S. Thirty (14 men and 16 women) non‐sarcopenic, non‐frail persons were enrolled in the control group. A panel of 27 cytokines, chemokines and growth factors was analyzed via a multiplex, magnetic bead‐based immunoassay on a Bio‐Plex® System with Luminex xMap Technology. A panel of 37 serum amino acids and derivatives was assessed by UPLC‐MS. Multi‐block partial least squares discriminant analysis (PLS‐DA) was employed to explore the relationship among inflammatory and amino acid profiles of people with PF&amp;S. Double cross‐validation procedures were used to validate the predictive ability of the PLS‐DA model.The optimal complexity of the PLS‐DA model was found to be three latent variables. The proportion of correct classification was 85.5 ± 4.4 for persons with PF&amp;S and 88.3 ± 3.6 for controls. As for the amino acid profile, people with PF&amp;S showed higher levels of aspartic acid, asparagine, taurine, citrulline, alpha‐aminobutyric acid, methionine, and glutamic acid. Increased levels of interleukin‐8, myeloperoxidase, and platelet derived growth factor‐BB were also found in people with PF&amp;S.The dissection of these patterns may provide novel insights into the role played by inflammatory mediators and protein/amino acid perturbations in the disabling cascade associated with PF&amp;S and possible new targets for interventions.Support or Funding InformationThis study was supported by the “Centro Studi Achille e Linda Lorenzon”, intramural research grants from the Catholic University of the Sacred Heart (D3.2 2013 and D3.2 2015), Innovative Medicines Initiative Joint Undertaking (IMI‐JU 115621), and Fondazione Roma (NCDs Call for Proposal 2013)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Optimizing the dosing schedule of l-asparaginase improves its anti-tumor activity in breast tumor-bearing mice

Proliferation of acute lymphoblastic leukemic cells is nutritionally dependent on the external supply of asparagine. l-asparaginase, an enzyme hydrolyzing l-asparagine in blood, is used for treatment of acute lymphoblastic leukemic and other related blood cancers. Although previous studies demonstrated that l-asparaginase suppresses the proliferation of cultured solid tumor cells, it remains unclear whether this enzyme prevents the growth of solid tumors in vivo. In this study, we demonstrated the importance of optimizing dosing schedules for the anti-tumor activity of l-asparaginase in 4T1 breast tumor-bearing mice. Cultures of several types of murine solid tumor cells were dependent on the external supply of asparagine. Among them, we selected murine 4T1 breast cancer cells and implanted them into BALB/c female mice kept under standardized light/dark cycle conditions. The growth of 4T1 tumor cells implanted in mice was significantly suppressed by intravenous administration of l-asparaginase during the light phase, whereas its administration during the dark phase failed to show significant anti-tumor activity. Decreases in plasma asparagine levels due to the administration of l-asparaginase were closely related to the dosing time-dependency of its anti-tumor effects. These results suggest that the anti-tumor efficacy of l-asparaginase in breast tumor-bearing mice is improved by optimizing the dosing schedule.

Diverse Metabolite Variations in Tea (Camellia sinensis L.) Leaves Grown Under Various Shade Conditions Revisited: A Metabolomics Study.

With the increase of tea (Camellia sinensis) consumption, its chemical or metabolite compositions play a crucial role in the determination of tea quality. In general, metabolite compositions of fresh tea leaves including shoots depend on plucking seasons and tea cultivators. Therefore, choosing a specific plucking time of tea leaves can provide use-specified tea products. Artificial control of tea growing, typically shade treatments, can lead to significant changes of the tea metabolite compositions. However, metabolic characteristics of tea grown under various shade treatment conditions remain unclear. Therefore, the objective of the current study was to explore effects of various shade conditions on metabolite compositions of tea through a 1H NMR-based metabolomics approach. It was noteworthy that the levels of catechins and their derivatives were only influenced at the initial time of shade treatments while most amino acids were upregulated as amounts of shade and periods were increased: that is, the levels of alanine, asparagine, aspartate, isoleucine, threonine, leucine, and valine in fresh tea leaves were conspicuously elevated when shade levels were raised from 90% to 100% and when period of shade treatments was increased by 20 days. Such increased synthesis of amino acids along with large reductions of glucose level reflected carbon starvation under the dark conditions, indicating remarkable proteolysis in the chloroplast of tea leaves. This study provides important information about making amino acid-enhanced tea products based on global characteristics of diverse tea leaf metabolites induced by various shade treatment conditions.

Nonconventional enzymatic method to determine free asparagine level in whole-grain wheat

A new enzymatic methodology is herein proposed to measure free asparagine content in wheat grains and to predict their potential for Maillard reaction products. Our model estimates the acrylamide levels generated during the industrial heat treatment of whole-grain wheat based on free asparagine and glucose measurements. We selected fifteen wheat varieties currently grown in Belgium as benchmark for the present study. While conventional chromatographic methods require a long and tedious multi-step sample preparation, the proposed method takes advantage of being simple and quick. Statistical analysis of free asparagine content indicates that selected wheat varieties can be classified into seven content levels from 0.0149% to 0.0216% of the dry matter. Based on our analysis, the varieties KWS Ozon, Benchmark and Pionier appears to be the most suitable for thermal processing (i.e. cooking applications).

Structure and function of the thermostable L-asparaginase from Thermococcus kodakarensis.

L-Asparaginases catalyse the hydrolysis of asparagine to aspartic acid and ammonia. In addition, L-asparaginase is involved in the biosynthesis of amino acids such as lysine, methionine and threonine. These enzymes have been used as chemotherapeutic agents for the treatment of acute lymphoblastic leukaemia and other haematopoietic malignancies since the tumour cells cannot synthesize sufficient L-asparagine and are thus killed by deprivation of this amino acid. L-Asparaginases are also used in the food industry and have potential in the development of biosensors, for example for asparagine levels in leukaemia. The thermostable type I L-asparaginase from Thermococcus kodakarensis (TkA) is composed of 328 amino acids and forms homodimers in solution, with the highest catalytic activity being observed at pH 9.5 and 85°C. It has a Km value of 5.5 mM for L-asparagine, with no glutaminase activity being observed. The crystal structure of TkA has been determined at 2.18 Å resolution, confirming the presence of two α/β domains connected by a short linker region. The N-terminal domain contains a highly flexible β-hairpin which adopts `open' and `closed' conformations in different subunits of the solved TkA structure. In previously solved L-asparaginase structures this β-hairpin was only visible when in the `closed' conformation, whilst it is characterized with good electron density in all of the subunits of the TkA structure. A phosphate anion resides at the active site, which is formed by residues from both of the neighbouring monomers in the dimer. The high thermostability of TkA is attributed to the high arginine and salt-bridge content when compared with related mesophilic enzymes.

Subacute oral toxicity assessment of benalaxyl in mice based on metabolomics methods

In this study, the metabolic responses of mice after 30 days of exposure to benalaxyl were assessed using NMR-based untargeted metabolomics and LC-MS-based targeted profiling of 20 amino acids. Urinary 1H NMR analyses revealed alterations in energy metabolism, lipid metabolism, vitamin B metabolism, the urea cycle and amino acid metabolism, and targeted analyses indicated that the serum levels of asparagine, histidine, lysine and aspartic acid were significantly altered. Additionally, significant oxidative stress was observed in the liver and kidney, although no apparent histopathological injury was observed. The tissue distribution indicated a significant stereoselectivity in the brain, where (−)-R-benalaxyl was enriched. These data provide a comprehensive picture of the subacute toxic effects of benalaxyl in mice. The results of this study suggested that, for a toxicity evaluation, metabolomics analysis is much more sensitive than traditional toxicological methods. The results also highlight the combined use of untargeted and targeted metabolomics approaches in evaluating the health risks of xenobiotics.

Amino acid profiles as potential biomarkers for pediatric cancers: a preliminary communication.

Childhood cancer remains one of the main cause of death in the pediatric population. Amino acids (AAs) level alterations in plasma are considered to play a role in carcinogenesis and further course of the disease. Seventy-seven children with cancer, including 47 with hematological and 30 with solid tumors were enrolled in this study and compared with healthy children. Twenty-two plasma-free AAs were determined by HPLC with fluorometric detection. The results revealed significant decrease in glutamine levels for oncological patients and significant increase in aspartic acid, glutamic acid, asparagine, serine, citrulline, alanine, GABA, tryptophan, methionine, valine, phenylalanine and isoleucine levels in cancer children versus control. Plasma-free AA profile as a biomarker, which combines metabolic and clinical data, as an innovative and interdisciplinary approach, may allow for faster detection of tumor occurrence, and in the future for monitoring patient during treatment, and possible prediction of cancer recurrence.

Salinity source alters mineral composition and metabolism of Cichorium spinosum

Spiny chicory (Cichorium spinosum L.) is used as a health promoting vegetable in Crete, where it is known as stamnagathi. In this paper, the effects of different isosmotic salt solutions on growth, mineral composition and metabolism of hydroponically-grown C. spinosum were investigated. Nine nutrient solutions (NS) were compared, particularly a basic NS used as control, and eight saline NS obtained by adding to the basic NS either NaCl, or KCl, or Na2SO4, or CaCl2 at two rates each, corresponding to two isosmotic salt levels. The osmotic potential at 20°C was −0.286MPa and −0.480MPa at the low and the high isosmotic salt level, respectively. C. spinosum proved to be highly tolerant to salinity, suffering only about 20% growth reduction at the high salinity level (53.6mmolL−1 CaCl2 or Na2SO4, and 80mmolL−1 NaCl or KCl), regardless of the salinity source. At the low salinity level (26.8mmolL−1 CaCl2 or Na2SO4, and 40mmolL−1 NaCl or KCl), only the bivalent ions reduced slightly the fresh shoot biomass, while only CaCl2 restricted the dry shoot biomass. Application of 1H NMR metabolomics to monitor fluctuations in plant metabolism caused by salinity revealed that γ-aminobutyric acid (GABA), glutamate, pyroglutamate, l-proline, and sucrose were the key osmoprotectants in salt-stressed C. spinosum. The levels of glutamine and asparagine, as well as organic acids were reduced by salinity while aromatic compounds had a minor leverage on the observed discriminations, regardless of the salt source, indicating lack of osmoprotection by these metabolites in salt-stressed C. spinosum. Salt-induced changes in tissue mineral levels did not seem to be associated with salinity stress. The present study showed that the osmotic potential level is the dominant factor for the impact of salinity on stamnagathi, but the salt source may also play a minor role, especially at lower salinity levels.

Metabolic risk factors associated with sudden cardiac death (SCD) during acute myocardial ischemia

ABSTRACTSudden cardiac death (SCD) is the leading cause of death worldwide. Myocardial ischemia (MI) is the most common underlying causal disorder for SCD. Metabolic risks leading to SCD during acute MI are still not fully understood. Here, using tissue metabolomics, we aimed to investigate myocardial metabolic alterations relevant to SCD events in an acute MI rat model induced by coronary artery ligation (CAL). Thirty-four rats were successfully performed CAL, of which 13 developed lethal ventricular tachyarrhythmia (LVTA)-SCD and 7 developed severe atrioventricular block (AB)-SCD. Fourteen rats that survived within 70 min after the ligation were served as peer controls. The partial least squares-discriminant analysis plots demonstrated clear separations between the SCD rats and controls, indicating obvious differences in myocardial metabolome between these rats. The levels of isoleucine, lactate, glutamate choline, phosphorylcholine, taurine and asparagine in ischemic myocardia were positively associated with LVTA-SCD events; in contrast, the levels of alanine, urea, phenylalanine, linoleic acid, elaidic acid and stearic acid were inversely correlated with LVTA-SCD events. The levels of glutamate and urea were positively and negatively relevant to AB-SCD events, respectively. The dangerous metabolites indicated that lower levels of energy substrates, severe hypoxia, the inhibition of transamination and hyper sympathetic excitement and reactive oxygen species in myocardia were vulnerable to SCD during acute MI. The results suggest fatal metabolic alterations correlated with SCD events during acute MI, which could offer novel clues for the prevention or treatment of acute MI-related SCD.

Effects of variety, year of cultivation and sulphur supply on the accumulation of free asparagine in the grain of commercial wheat varieties

Free asparagine concentration, which is the determining factor for acrylamide-forming potential in cereals, was measured in grain from wheat grown in field trials in the United Kingdom in 2011–2012 and 2012–2013. There were 25 varieties in 2012 and 59 in 2013, with eleven present in both trials. The trials were split-plot, with half of each plot supplied with sulphur and the other half not. The varietal means (mmol per kg) for free asparagine in the sulphur-fed wheat ranged from 1.521 to 2.687 in 2011–2012 and 0.708 to 11.29 in 2012–2013. Eight varieties were identified as having consistently low free asparagine concentration. There was a differential response of varieties to sulphur, and much higher levels of free asparagine in 2012–2013 versus 2011–2012. Given the short commercial lifespan of some wheat varieties, it is concluded that information on free asparagine concentration should be made available when a variety is launched.