High-resolution 1H NMR Spectroscopy Research Articles

Quantitative Metabolomic Analysis of the Rat Hippocampus: Effects of Age and of the Development of Alzheimer's Disease-Like Pathology.

Alzheimer's disease (AD) is the most common type of dementia in the elderly. Incomplete knowledge about the pathogenesis of this disease determines the absence of medications for the treatment of AD today. Animal models can provide the necessary knowledge to understand the mechanisms of biochemical processes occurring in the body in health and disease. To identify the most promising metabolomic predictors and biomarkers reflecting metabolic disorders in the development of AD signs. High resolution 1H NMR spectroscopy was used for quantitative metabolomic profiling of the hippocampus of OXYS rats, an animal model of sporadic AD, which demonstrates key characteristics of this disease. Animals were examined during several key periods: 20 days group corresponds to the "preclinical" period preceding the development of AD signs, during their manifestation (3 months), and active progression (18 months). Wistar rats of the same age were used as control. Ranges of variation and mean concentrations were established for 59 brain metabolites. The main metabolic patterns during aging, which are involved in energy metabolism pathways and metabolic shifts of neurotransmitters, have been established. Of particular note is the significant increase of scyllo-inositol and decrease of hypotaurine in the hippocampus of OXYS rats as compared to Wistars for all studied age groups. We suggest that the accumulation of scyllo-inositol and the reduction of hypotaurine in the brain, even at an early age, can be considered as predictors and potential biomarkers of the development of AD signs in OXYS rats and, probably, in humans.

Quantitative Metabolomic Analysis of Changes in the Rat Blood Serum during Autophagy Modulation: A Focus on Accelerated Senescence.

Autophagy is involved in the maintenance of cellular homeostasis and the removal of damaged proteins and organelles and is necessary to maintain cell metabolism in conditions of energy and nutrient deficiency. A decrease in autophagic activity plays an important role in age-related diseases. However, the metabolic response to autophagy modulation remains poorly understood. Here, we for the first time explored the effects of (1) autophagy activation by 48 h fasting, (2) inhibition by chloroquine (CQ) treatment, and (3) combined effects of fasting and CQ on the quantitative composition of metabolites in the blood serum of senescent-accelerated OXYS and control Wistar rats at the age of 4 months. By means of high-resolution 1H NMR spectroscopy, we identified the quantitative content of 55 serum metabolites, including amino acids, organic acids, antioxidants, osmolytes, glycosides, purine, and pyrimidine derivatives. Groups of 48 h fasting (induction of autophagy), CQ treatment (inhibition of autophagy), and combined effects (CQ + fasting) are clearly separated from control groups by principal component analysis. Fasting for 48 h led to significant changes in the serum metabolomic profile, primarily affecting metabolic pathways related to fatty acid metabolism, and led to metabolism of several amino acids. Under CQ treatment, the most affected metabolites were citrate, betaine, cytidine, proline, tryptophan, glutamate, and mannose. As shown by two-way ANOVA, for many metabolites the effects of autophagy modulation depend on the animal genotype, indicating a dysregulation of metabolome reactivity in OXYS rats. Thus, the metabolic responses to modulation of autophagy in OXYS rats and Wistar rats are different. Altered metabolites in OXYS rats may serve as potential biomarkers of the manifestation of the signs of accelerated aging. Metabolic signatures characteristic to fasting and CQ treatment revealed in this work might provide a better understanding of the connections between metabolism and autophagy.

Phosphate buffer-catalyzed kinetics of mutarotation of glucosamine investigated by NMR spectroscopy

Glucosamine (2-amino-2-deoxy-d-glucose, GlcN) is a naturally occurring amino monosaccharide that is essential for a variety of biological functions, it is mainly involved in the formation of polysaccharide structures. It was recently reported to enable the imaging of cancerous tumors as an exogenous contrast agent using the MRI technique of chemical exchange saturation transfer (CEST). In preparation for the clinical use of GlcN, its anomeric equilibrium and mutarotation rate constants were directly investigated in this study utilizing high resolution 1H and 13C NMR spectroscopy. The effects of GlcN concentration, temperature, pH and buffer on the mutarotation rate constant and mutarotation equilibrium were measured. The mutarotation rate constant increased markedly with increasing GlcN concentrations. The rate constant of mutarotation of GlcN at room temperature was 2.2 × 10−4 - 5.0 × 10−4 s−1 at concentrations of 0.02–0.5 M, corresponding to a time of 3.8–1.7 h to reach 95% equilibrium. The anomeric ratio was strongly pH-dependent. The influence of phosphate buffer on the apparent rate constant of GlcN mutarotation was investigated. For phosphate buffer saline values between 0 and 50 mM, there was a six-fold increase in rate at pH 7.0. The mutarotation rate constant rose rapidly with pH at a phosphate concentration of 50 mM: from 0.4 × 10−3 s−1 at pH 5.0 to 7.8 × 10−3 s−1 at pH 9.4, suggesting that the catalysis is due to the HPO42− and PO43− ions. These findings might help researchers design the experimental setting for employing GlcN for cancer detection using GlcN-CEST MRI.

Impact of reduced uterine perfusion pressure model of preeclampsia on metabolism of placenta, maternal and fetal hearts

Preeclampsia is a cardiovascular pregnancy complication characterised by new onset hypertension and organ damage or intrauterine growth restriction. It is one of the leading causes of maternal and fetal mortality in pregnancy globally. Short of pre-term delivery of the fetus and placenta, treatment options are limited. Consequently, preeclampsia leads to increased cardiovascular disease risk in both mothers and offspring later in life. Here we aim to examine the impact of the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia on the maternal cardiovascular system, placental and fetal heart metabolism. The surgical RUPP model was induced in pregnant rats by applying silver clips around the aorta and uterine arteries on gestational day 14, resulting in ~ 40% uterine blood flow reduction. The experiment was terminated on gestational day 19 and metabolomic profile of placentae, maternal and fetal hearts analysed using high-resolution 1H NMR spectroscopy. Impairment of uterine perfusion in RUPP rats caused placental and cardiac hypoxia and a series of metabolic adaptations: altered energetics, carbohydrate, lipid and amino acid metabolism of placentae and maternal hearts. Comparatively, the fetal metabolic phenotype was mildly affected. Nevertheless, long-term effects of these changes in both mothers and the offspring should be investigated further in the future.

Construction of Cholesterol Oxime Ether Derivatives Containing Isoxazoline/Isoxazole Fragments and Their Agricultural Bioactive Properties/Control Efficiency.

To explore natural-product-based pesticidal candidates and high value-added application of cholesterol in agriculture, oximinoether derivatives of cholesterol-containing isoxazoline/isoxazole fragments (I-1∼I-16 and II-1∼II-18) were semiprepared by structural optimization of cholesterol. Their structures were characterized by optical rotation, high-resolution mass spectrometry (HRMS), IR, and 1H NMR spectroscopy. Particularly, the Z configurations of oxime fragments at the C-7 position of target compounds were undoubtedly determined by X-ray crystallography. Against Mythimna separata Walker, compounds 3e, I-8, I-14, and II-3 showed 2.4-2.7-fold growth inhibitory activity of the precursor cholesterol. Against Plutella xylostella Linnaeus, compounds I-6, I-7, and I-9 showed 2.4-2.7-fold oral toxicity of cholesterol. Against Aphis citricola Van der Goot, compounds 2e and II-15 exhibited 4.9 and 5.8-fold aphicidal activity of cholesterol, respectively. Notably, they showed good control effects (3.0-5.0-fold promising control efficiency of 1) against A. citricola in the greenhouse. Structure-activity relationships (SARs) suggested that the C-3 hydroxyl group and the C-7 position of cholesterol are two important modification sites. It will pave the way for future structural optimization and application of cholesterol derivatives as potential pesticidal agents in agriculture.

Resolving Entangled JH-H-Coupling Patterns for Steroidal Structure Determinations by NMR Spectroscopy.

For decades, high-resolution 1H NMR spectroscopy has been routinely utilized to analyze both naturally occurring steroid hormones and synthetic steroids, which play important roles in regulating physiological functions in humans. Because the 1H signals are inevitably superimposed and entangled with various JH–H splitting patterns, such that the individual 1H chemical shift and associated JH–H coupling identities are hardly resolved. Given this, applications of thess information for elucidating steroidal molecular structures and steroid/ligand interactions at the atomic level were largely restricted. To overcome, we devoted to unraveling the entangled JH–H splitting patterns of two similar steroidal compounds having fully unsaturated protons, i.e., androstanolone and epiandrosterone (denoted as 1 and 2, respectively), in which only hydroxyl and ketone substituents attached to C3 and C17 were interchanged. Here we demonstrated that the JH–H values deduced from 1 and 2 are universal and applicable to other steroids, such as testosterone, 3β, 21-dihydroxygregna-5-en-20-one, prednisolone, and estradiol. On the other hand, the 1H chemical shifts may deviate substantially from sample to sample. In this communication, we propose a simple but novel scheme for resolving the complicate JH–H splitting patterns and 1H chemical shifts, aiming for steroidal structure determinations.

Synthesis and characterization of heteroleptic rare earth double-decker complexes involving tetradiazepinoporphyrazine and phthalocyanine macrocycles.

Reaction of (2,3,9,10,16,17,23,24-octabutylphthalocyaninato)lanthanide(iii) acetylacetonates (BuPcLn(acac), 1a-c, Ln = Lu (a), Eu (b), La (c)) with a tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazine ligand (tBuPhDzPzH2, 2) produced sandwich compounds (tBuPhDzPz)Ln(BuPc) (3a-c), which represent the first heteroleptic double-deckers incorporating both Pc and DzPz decks. A combination of high-resolution mass spectrometry, UV-Vis/NIR, MCD, and 1H NMR spectroscopy, and square-wave voltammetry provided unambiguous characterization of target complexes 3 indicating that their spectral and electrochemical properties are generally intermediate with respect to their homoleptic relatives. Based on the data of solution-state 1H-1H NMR (COSY, NOESY) correlation spectroscopy supported by DFT calculations, a dimerization tendency of compounds 3 proportional to the Ln(iii) ion size was found. The spectroelectrochemical study of 3 and the corresponding homoleptic double-deckers revealed a pronounced tendency to aggregation of the one-electron oxidized forms of DzPz-containing double-decker complexes compared to homoleptic Pc2Ln compounds.

NMR-Based Metabolomic Study of Purple Carrot Optimal Harvest Time for Utilization as a Source of Bioactive Compounds

The carrot (Daucus carota L.), one of the most important vegetable crops in the world, is recognized as a source of different compounds with healthy properties. Due to their high content of anthocyanins, purple carrots have been used as a natural colorant source to face the increasing demand of consumers for non-synthetic products. However, the root developmental stage can greatly affect the phytochemical composition and, in this regard, the identification of chemical biomarkers for the optimal harvest time would be of paramount interest both from a nutritional point of view and for the agri-food industry. In the present work, the metabolic profiling of purple carrots was monitored over four months using high-resolution 1H NMR spectroscopy. Several metabolites were identified, and their quantitative variations allowed for the investigation of the carrot development processes. The metabolic profile analysis showed an increase in amino acid, NAD, and caffeic acid levels during carrot development. A more tardive harvest in December entailed an increase in levels of luteolin-7-O-glucoside, chlorogenic acid, falcarinol, and γ-aminobutyrate, and a decrease in carotenoids and ω-6 fatty acid. The results showed how the harvest time affects the composition in terms of flavonoids, phenols, and polyacetylenes, therefore, improving the bioactive compound content.

Reduced lipolysis in lipoma phenocopies lipid accumulation in obesity

BackgroundElucidation of lipid metabolism and accumulation mechanisms is of paramount importance to understanding obesity and unveiling therapeutic targets. In vitro cell models have been extensively used for these purposes, yet, they do not entirely reflect the in vivo setup. Conventional lipomas, characterized by the presence of mature adipocytes and increased adipogenesis, could overcome the drawbacks of cell cultures. Also, they have the unique advantage of easily accessible matched controls in the form of subcutaneous adipose tissue (SAT) from the same individual. We aimed to determine whether lipomas are a good model to understand lipid accumulation.MethodsWe histologically compared lipomas and control SAT, followed by assessment of the lipidome using high-resolution 1H NMR spectroscopy and ESI-IT mass spectrometry. RNA-sequencing was used to obtain the transcriptome of lipomas and the matched SAT.ResultsWe found a significant increase of small-size (maximal axis < 70 µm) and very big (maximal axis > 150 µm) adipocytes within lipomas. This suggests both enhanced adipocyte proliferation and increased lipid accumulation. We further show that there is no significant change in the lipid composition compared to matched SAT. To better delineate the pathophysiology of lipid accumulation, we considered two groups with different genetic backgrounds: (1) lipomas with HMGA2 fusions and (2) without gene fusions. To reduce the search space for genes that are relevant for lipid pathophysiology, we focused on the overlapping differentially expressed (DE) genes between the two groups. Gene Ontology analysis revealed that DE genes are enriched in pathways related to lipid accumulation.ConclusionsWe show that the common shared lipid accumulation mechanism in lipoma is a reduction in lipolysis, with most gene dysregulations leading to a reduced cAMP in the adipocyte. Superficial lipomas could thus be used as a model for lipid accumulation through altered lipolysis as found in obese patients.

Experimental and theoretical evidence for hydrogen doping in polymer solution-processed indium gallium oxide

The field-effect electron mobility of aqueous solution-processed indium gallium oxide (IGO) thin-film transistors (TFTs) is significantly enhanced by polyvinyl alcohol (PVA) addition to the precursor solution, a >70-fold increase to 7.9 cm2/Vs. To understand the origin of this remarkable phenomenon, microstructure, electronic structure, and charge transport of IGO:PVA film are investigated by a battery of experimental and theoretical techniques, including In K-edge and Ga K-edge extended X-ray absorption fine structure (EXAFS); resonant soft X-ray scattering (R-SoXS); ultraviolet photoelectron spectroscopy (UPS); Fourier transform-infrared (FT-IR) spectroscopy; time-of-flight secondary-ion mass spectrometry (ToF-SIMS); composition-/processing-dependent TFT properties; high-resolution solid-state 1H, 71Ga, and 115In NMR spectroscopy; and discrete Fourier transform (DFT) analysis with ab initio molecular dynamics (MD) liquid-quench simulations. The 71Ga{1H} rotational-echo double-resonance (REDOR) NMR and other data indicate that PVA achieves optimal H doping with a Ga···H distance of ∼3.4 Å and conversion from six- to four-coordinate Ga, which together suppress deep trap defect localization. This reduces metal-oxide polyhedral distortion, thereby increasing the electron mobility. Hydroxyl polymer doping thus offers a pathway for efficient H doping in green solvent-processed metal oxide films and the promise of high-performance, ultra-stable metal oxide semiconductor electronics with simple binary compositions.

Design and synthesis of C-ring quinoxaline-substituted sinomenine 1,2,3-triazole derivatives via click reactions

The synthesis of C-ring quinoxaline-substituted sinomenine 1,2,3-triazole derivatives at the 4-OH via click reactions is accomplished, and a total of 16 novel sinomenine double N-heterocyclic derivatives are obtained in 74%–95% yields. The C-ring is first transformed into a 1,2-diketone structure under the action of hydrochloric acid, and then reacted with o-phenylenediamine to obtain a C-ring quinoxaline-substituted structure. The 4-OH of sinomenine reacts with chloropropyne to give an alkynyl sinomenine, and then reacts with sodium azide and various benzyl chlorides to give the target compounds. All the synthesized derivatives are characterized by Fourier-transform infrared spectrometry, high resolution mass spectrometry, 1H NMR, and 13C NMR spectroscopy.

High-resolution 1H-NMR spectroscopy indicates variations in metabolomics profile of follicular fluid from women with advanced maternal age.

To reveal whether there are differences in follicular fluid metabolomics profile of women with advanced maternal age (AMA). The group with advanced maternal age includes 23 patients above the age of 40, and the control group includes 31 patients aged between 25 and 35years and AMH values above 1.1ng/mL with no low ovarian response history. A single follicular fluid sample from a MII oocyte obtained during the oocyte pick-up procedure was analyzed with high-resolution 1H-NMR (nuclear magnetic resonance) spectroscopy. The results were evaluated using advanced bioinformatics analysis methods. Statistical analysis of the NMR spectroscopy data from two groups showed that α-glucose and β-glucose levels of follicular fluid were decreased in the patients with AMA, while in contrast, lactate and trimethylamine N-oxide (TMAO) levels were increased in these patients compared with the controls. In addition to these, there was an increase in alanine levels and a decrease in acetoacetate levels in patients with AMA. However, these changes were not statistically significant. Obtained results suggest that the follicular cell metabolism of patients with AMA is different from controls. These environmental changes could be associated with the low success rates of IVF treatment seen in these patients.

Determination of the &lt;i&gt;p&lt;/i&gt;/&lt;i&gt;o&lt;/i&gt;-Isomer Product Ratios in Electrophilic Aromatic Nitration of Alkylbenzenes Using High Resolution &lt;SUP&gt;1&lt;/SUP&gt;H NMR Spectroscopy

High resolution 1H NMR spectroscopy, an increasingly available instrumental method, is used in undergraduate organic laboratory practice as a simpler alternative to gas chromatographic method for the direct determination of the p/o ratios of the crude reaction product from the nitration of alkylbenzenes. The choice of isopropylbenzene as a substrate illustrates that steric effect can be significant in controlling regioselectivity in electrophilic aromatic substitution reactions.

Poly(2-propyl-2-oxazoline)s in Aqueous Methanol: To Dissolve or not to Dissolve

At room temperature, poly(N-isopropylacrylamide) (PNIPAM) is soluble in water and methanol, but it is not soluble in certain water/methanol mixtures. This phenomenon, known as cononsolvency, has been explored in great detail experimentally and theoretically in an attempt to understand the complex interactions occurring in the ternary PNIPAM/water/co-nonsolvent system. Yet little is known about the effects of the polymer structure on cononsolvency. To address this point, we investigated the temperature-dependent solution properties in water, methanol, and mixtures of the two solvents of poly(2-cyclopropyl-2-oxazoline) (PcyPOx) and two structural isomers of PNIPAM (Mn ∼ 11 kg/mol): poly(2-isopropyl-2-oxazoline) (PiPOx) and poly(2-n-propyl-2-oxazoline) (PnPOx). The phase diagram of the ternary water/methanol/poly(2-propyl-2-oxazolines) (PPOx) systems, constructed based on cloud point (TCP) measurements, revealed that PnPOx exhibits cononsolvency in water/methanol mixtures. In contrast, methanol acts as a cosolvent for PiPOx and PcyPOx in water. The enthalpy, ΔH, and temperature, Tmax, of the coil-to-globule transition of the three polymers in various water/methanol mixtures were measured by high-sensitivity differential scanning calorimetry. Tmax follows the same trends as TCP, confirming the cononsolvency of PnPOx and the cosolvency of PiPOx and PcyPOx. ΔH decreases linearly as a function of the methanol content for all PPOx systems. Ancillary high-resolution 1H NMR spectroscopy studies of PPOx solutions in D2O and methanol-d4, coupled with DOSY and NOESY experiments revealed that the n-propyl group of PnPOx rotates freely in D2O, whereas the rotation of the isopropyl and cyclopropyl groups of PiPOx and PcyPOx, respectively, is limited due to steric restriction. This factor appears to play an important role in the case of the PPOxs/water/methanol ternary system.

A novel tetraphenylethylene derivative: 4-methyl-N-[3-(1,2,2-triphenylethenyl)phenyl]benzenesulfonamide with aggregation-induced emission.

The novel tetraphenylethylene derivative 4-methyl-N-[3-(1,2,2-triphenylethenyl)phenyl]benzenesulfonamide (abbreviated as MTBF), C33H27NO2S, was synthesized successfully and characterized by single-crystal X-ray diffraction, high-resolution mass spectroscopy and 1H NMR spectroscopy. MTBF crystallizes in the centrosymmetric monoclinic space group P21/c. In the crystal structure, the MTBF molecules are connected into a one-dimensional band and then a two-dimensional sheet by hydrogen bonds of the N-H...O and C-H...O types. The sheets are further linked to produce a three-dimensional network via C-H...π interactions. The molecules aggregate via these intermolecular forces, which restrain the intramolecular motions (RIM) and decrease the energy loss in the aggregation state, so as to open the radiative channels, and thus MTBF exhibits excellent fluorescence by aggregation-induced emission (AIE) enhancement.

Removal of Cs-137 and Sr-90 from reactor actual liquid waste samples using a new synthesized bionanocomposite-based carboxymethylcellulose

Abstract A new biosorbent containing vinylsulphonic acid and 2-acryloamido-2-methyl-1-propanesulphonic acid in the presence of magnetic nanoparticles, iron (III) oxide, grafted to carboxymethylcellulose sodium salt P(VSA/AMPSO3H/MNPs)-g-CMC bionanocomposite material (BNC) has been synthesized by γ radiation induced grafting copolymerization technique. The effect of comonomer, crosslinker, CMC concentration and the absorbed dose (kGy) on the grafting efficiency and swelling degree was studied. The BNC has been successfully synthesized and the structure of the prepared BNC was confirmed by Fourier transform infrared (FTIR), thermal analysis (TGA and DTA), X-ray powder diffraction (XRD), high-resolution 1H NMR spectroscopy and scanning electron microscopy (SEM) micrograph. Batch studies relevant to adsorption of Cs-137 and Sr-90 from the reactor actual liquid waste samples by the BNC were performed as a function of contact time, solution pH, metal ion concentration, and temperature in simulation studies using the γ emitting isotopes Cs-134 and Sr-85 as representatives of Cs-137 and Sr-90, respectively. Those studies were used to find out the best conditions for isolation of Cs-137 and Sr-90 from reactor actual liquid waste. The isotherms and kinetics were analyzed using different models at 25 °C. The maximum capacity of BNC was found to be 297 and 330 mg g−1 for Cs(I) and Sr(II) metal ions, respectively.

Molecular-scale investigation of soil fulvic acid and water-extractable organic matter by high-resolution mass spectrometry and 1H NMR spectroscopy

Environmental contextNotwithstanding the environmental and geochemical significance of soil dissolved organic matter (DOM), its molecular components are still not well characterised. This study investigates chemical similarities and differences between two widely used forms of soil DOM: water-extractable organic matter and fulvic acids. The findings will guide appropriate extraction and purification protocols in future studies related to soil DOM. AbstractDissolved organic matter (DOM) is the most active fraction of soil organic matter (SOM), which has both environmental and geochemical importance. However, the extraction of DOM from soils is still ambiguous. Instead, operational concepts, such as fulvic acid (FA) and water-extractable organic matter (WEOM), are widely used in practice. In this study, the molecular components of FA and WEOM extracted from two standard soils were investigated by using electrospray ionisation coupled with Fourier-transform ion cyclotron resonance mass spectrometry and proton nuclear magnetic resonance (1H NMR) spectroscopy to clarify the molecular similarities and differences between them. The results revealed that WEOM and FA shared many of the same molecules, which accounted for 64% and 82% of the total numbers of molecules for WEOM and FA respectively. However, WEOM displayed higher chemical and molecular diversities than FA. Detailed analysis revealed that the extraction and desalination procedure of FA led to the loss of lignin, protein and carbohydrate compounds, but induced preferential release of some tannin-like molecules from the aggregate- or organic mineral-associated SOM. Based on the results of the present study, water extraction combined with desalination through a functionalised styrene divinylbenzene polymer-based solid phase extraction is more reliable to retain the molecular diversity of soil DOM.

Metabolic Profiling of the Hippocampus of Rats Experiencing Nicotine-Withdrawal Symptoms.

Nicotine-withdrawal symptoms have been indicated as a possible risk factor for neuropsychiatric events, such as depression and suicide, during use of smoking-cessation drugs. We aimed to investigate whether the results of the metabolomic analysis of the rat brain reflect nicotine-withdrawal symptoms. We also aimed to investigate the relative changes in each metabolite in the brains of rats with nicotine-withdrawal symptoms. We created rats experiencing nicotine-withdrawal symptoms through repeat administration of nicotine followed by a 12-h withdrawal period, and rats recovered from nicotine-withdrawal symptoms followed by an 18-h withdrawal period. We then implemented brain metabolic profiling by combining high-resolution magic-angle spinning 1H-NMR spectroscopy with partial least square discriminant analysis (PLS-DA). We found that metabolic profiling of the brain reflects the state during nicotine-withdrawal symptoms and the state after recovery from nicotine-withdrawal symptoms. Additionally, N-acetylaspartate and glutamate increased and aspartate, γ-aminobutyric acid (GABA), and creatine decreased in the hippocampus of rats experiencing nicotine-withdrawal symptoms. Therefore, it is suggested that neurogenesis and neuronal differentiation could be changed and abnormal energy metabolism could occur in the hippocampus during nicotine-withdrawal symptoms.

Control of the polyamine biosynthesis pathway by G2-quadruplexes.

G-quadruplexes are naturally-occurring structures found in RNAs and DNAs. Regular RNA G-quadruplexes are highly stable due to stacked planar arrangements connected by short loops. However, reports of irregular quadruplex structures are increasing and recent genome-wide studies suggest that they influence gene expression. We have investigated a grouping of G2-motifs in the UTRs of eight genes involved in polyamine biosynthesis, and concluded that several likely form novel metastable RNA G-quadruplexes. We performed a comprehensive biophysical characterization of their properties, comparing them to a reference G-quadruplex. Using cellular assays, together with polyamine-depleting and quadruplex-stabilizing ligands, we discovered how some of these motifs regulate and sense polyamine levels, creating feedback loops during polyamine biosynthesis. Using high-resolution 1H-NMR spectroscopy, we demonstrated that a long-looped quadruplex in the AZIN1 mRNA co-exists in salt-dependent equilibria with a hairpin structure. This study expands the repertoire of regulatory G-quadruplexes and demonstrates how they act in unison to control metabolite homeostasis.

Neuroprotective effects of Foeniculum vulgare seeds extract on lead-induced neurotoxicity in mice brain

The present study investigates the neuroprotective effects of Foeniculum vulgare seeds in a lead (Pb)-induced brain neurotoxicity mice model. The dried seeds extract of Foeniculum vulgare was prepared with different concentrations of organic solvents (ethanol, methanol, n-hexane). The in vitro antioxidant activity of Foeniculum vulgare seed extracts was assessed through DPPH assay and the chemical composition of the extracts was determined by high-resolution 1H NMR spectroscopy. The age-matched male Balb/c mice (divided into 9 groups) were administered with 0.1% Pb and 75% and 100% ethanol extracts of Foeniculum vulgare seeds at a dose of 200 mg/kg/day and 20 mg/kg/day. The maximum antioxidant activity was found for 75% ethanol extract, followed by 100% ethanol extract. Gene expression levels of oxidative stress markers (SOD1 and Prdx6) and the three isoforms of APP (APP common, 770 and 695), in the cortex and hippocampus of the treated and the control groups were measured. Significant increase in APP 770 expression level while a substantial decrease was observed for SOD1, Prdx6 and APP 695 expression in Pb-treated groups. Interestingly, the deranged expression levels were significantly normalized by the treatment with ethanol extracts of Foeniculum vulgare seeds (specifically at dose of 200 mg/kg/day). Furthermore, the Pb-induced morphological deterioration of cortical neurons was significantly improved by the ethanol extracts of Foeniculum vulgare seeds. In conclusion, the present findings highlight the promising therapeutic potential of Foeniculum vulgare to minimize neuronal toxicity by normalizing the expression levels of APP isoforms and oxidative stress markers.