Quantitative ¹³C Traces of Glucose Fate in Hepatitis B Virus-Infected Hepatocytes

Quantitative characterization of 13C-labeled metabolites is an important part of the stable isotope tracing method widely used in metabolic flux analysis. Given the long relaxation time and low sensitivity of 13C nuclei, direct measurement of 13C-labeled metabolites using one-dimensional 13C NMR often fails to meet the demand of metabolomics studies, especially with large numbers of samples and metabolites having low abundance. Although HSQC-based 2D NMR methods have improved sensitivity with inversion detection, they are time-consuming and thus unsuitable for high-throughput absolute quantification of 13C-labeled metabolites. In this study, we developed a method for absolute quantification of 13C-labeled metabolites using naturally abundant TSP as a reference with the first increment of the HMQC pulse sequence, taking polarization transfer efficiencies into consideration. We validated this method using a mixture of 13C-labeled alanine, methionine, glucose, and formic acid together with a mixture of alanine, lactate, glycine, uridine, cytosine, and hypoxanthine, which have natural 13C abundance with known concentrations. We subsequently applied this method to analyze the flux of glucose in HepG2 cells infected with hepatitis B virus (HBV). The results showed that HBV infection increased the cellular uptake of glucose, stimulated glycolysis, and enhanced the pentose phosphate and hexosamine pathways for biosynthesis of RNA and DNA and nucleotide sugars to facilitate HBV replication. This method saves experimental time and provides a possibility for absolute quantitative tracking of the 13C-labeled metabolites for high-throughput studies

Metabonomic Analysis Reveals the CCl₄-Induced Systems Alterations for Multiple Rat Organs

CCl₄-induced metabonomic changes have been extensively studied for mammalian liver, and such changes have not been reported for other organs. To investigate the CCl₄ effects on other organs, we analyzed the CCl₄-induced metabonomic changes in rat kidney, lung, and spleen using ¹H NMR-based metabonomics approaches with complementary information on serum clinical chemistry and histopathology. We found that acute CCl₄ exposure caused significant level elevation for creatine and decline for glucose, taurine, trimethylamine, uridine, and adenosine in rat kidney. CCl₄-treatment also induced elevation of amino acids (isoleucine, leucine, valine, threonine, alanine, lysine, ornithine, methionine, tyrosine, phenylalanine, and histidine), creatine, and betaine in rat lung together with depletion of glycogen, glucose, taurine, glycine, and hypoxanthine. Furthermore, CCl₄ caused elevation of lactate, alanine, betaine, and uracil in rat spleen accompanied with decline for glucose, choline, and hypoxanthine. These observations indicated that CCl₄ caused oxidative stresses to multiple rat organs and alterations of their functions including renal osmotic regulations, accelerated glycolysis, and protein and nucleotide catabolism. These findings provide essential information on CCl₄ toxicity to multiple rat organs and suggest that systems toxicological views are required for metabonomic studies of toxins by taking many other organs into consideration apart from so-called targeted ones

Gallic Acid Intake Induces Alterations to Systems Metabolism in Rats

Gallic acid (GA) and its metabolites are polyphenolic compounds present in daily diets and herbal medicines. To understand the GA effects on the endogenous metabolism of mammals, we systematically analyzed the metabonomic responses of rat plasma, liver, urine, and feces to a single GA dosage of 120 and 600 mg/kg, which were below the no-obvious-adverse-effect-level of 1 g/kg for rats. Clinical chemistry and histopathological assessments were conducted to provide complementary information. Our results showed that GA intake induced significant metabonomic changes in multiple rat biological matrices. Such changes were more outstanding in liver than in the other matrices and clearly showed dose- and time-dependence. The results suggested GA-induced promotion of oxidative stress as the major effect. High-dose GA caused significant metabolic changes involving glycogenolysis, glycolysis, TCA cycle, and metabolism of amino acids, purines, and pyrimidines, together with gut microbiota functions. Low-dose GA only caused some urinary metabonomic changes and to a much less degree. The GA-induced liver metabonomic changes were not completely recoverable within a week, although such recovery completed in plasma, urine, and feces within 80 h. These findings provided new essential information on the effects of dietary polyphenols and demonstrated the great potential of this nutrimetabonomics approach

Age-Related Topographical Metabolic Signatures for the Rat Gastrointestinal Contents

Symbiotic gut microbiota is essential for mammalian physiology and analyzing the metabolite compositions of gastrointestinal contents is vital for understanding the microbiome–host interactions. To understand the developmental dependence of the topographical metabolic signatures for the rat gastrointestinal contents, we systematically characterized the metabolite compositional variations of the contents in rat jejunum, ileum, cecum, and colon for two age-groups using ¹H NMR spectroscopy and multivariate analysis. Significant topographical metabolic variations were present for the jejunal, ileal, cecal, colonic contents, and feces, reflecting the absorption functions for each intestinal region and the gut microbiota therein. The concentrations of amino acids, lactate, creatine, choline, bile acids, uracil and urocanate decreased drastically from jejunal to ileal contents followed with steady decreases from cecal content to feces. Short-chain fatty acids (SCFAs) and arabinoxylan-related carbohydrates had highest levels in cecal content and feces, respectively. Such topographical metabolic signatures for the intestinal contents varied with animal age highlighted by the level changes for lactate, choline, taurine, amino acids, carbohydrates, keto-acids, and SCFAs. These findings provided essential information for the topographical metabolic variations in the gastrointestinal tract and demonstrated metabolic profiling as a useful approach for understanding host–microbiome interactions and functional status of the gastrointestinal regions

Effect of Carotene and Lycopene on the Risk of Prostate Cancer: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies

<div><p>Background</p><p>Many epidemiologic studies have investigated the association between carotenoids intake and risk of Prostate cancer (PCa). However, results have been inconclusive.</p><p>Methods</p><p>We conducted a systematic review and dose-response meta-analysis of dietary intake or blood concentrations of carotenoids in relation to PCa risk. We summarized the data from 34 eligible studies (10 cohort, 11 nested case-control and 13 case-control studies) and estimated summary Risk Ratios (RRs) and 95% confidence intervals (CIs) using random-effects models.</p><p>Results</p><p>Neither dietary β-carotene intake nor its blood levels was associated with reduced PCa risk. Dietary α-carotene intake and lycopene consumption (both dietary intake and its blood levels) were all associated with reduced risk of PCa (RR for dietary α-carotene intake: 0.87, 95%CI: 0.76–0.99; RR for dietary lycopene intake: 0.86, 95%CI: 0.75–0.98; RR for blood lycopene levels: 0.81, 95%CI: 0.69–0.96). However, neither blood α-carotene levels nor blood lycopene levels could reduce the risk of advanced PCa. Dose-response analysis indicated that risk of PCa was reduced by 2% per 0.2mg/day (95%CI: 0.96–0.99) increment of dietary α-carotene intake or 3% per 1mg/day (95%CI: 0.94–0.99) increment of dietary lycopene intake.</p><p>Conclusions</p><p>α-carotene and lycopene, but not β-carotene, were inversely associated with the risk of PCa. However, both α-carotene and lycopene could not lower the risk of advanced PCa.</p></div

The literature search process.

<p>The literature search process.</p

Revealing the Metabonomic Variation of Rosemary Extracts Using ¹H NMR Spectroscopy and Multivariate Data Analysis

The molecular compositions of rosemary (Rosmarinus officinalis L.) extracts and their dependence on extraction solvents, seasons, and drying processes were systematically characterized using NMR spectroscopy and multivariate data analysis. The results showed that the rosemary metabonome was dominated by 33 metabolites including sugars, amino acids, organic acids, polyphenolic acids, and diterpenes, among which quinate, cis-4-glucosyloxycinnamic acid, and 3,4,5-trimethoxyphenylmethanol were found in rosemary for the first time. Compared with water extracts, the 50% aqueous methanol extracts contained higher levels of sucrose, succinate, fumarate, malonate, shikimate, and phenolic acids, but lower levels of fructose, glucose, citrate, and quinate. Chloroform/methanol was an excellent solvent for selective extraction of diterpenes. From February to August, the levels of rosmarinate and quinate increased, whereas the sucrose level decreased. The sun-dried samples contained higher concentrations of rosmarinate, sucrose, and some amino acids but lower concentrations of glucose, fructose, malate, succinate, lactate, and quinate than freeze-dried ones. These findings will fill the gap in the understanding of rosemary composition and its variations

Subgroup analysis regarding the association between carotenoids consumption and PCa risk.

<p>Abbreviations: NCCS, nested case-control study; CCS, case-control study; BMI, body mass index; FHPC, family history of prostate cancer; PA, physical activity; NAM, No adjustment; CI, confidence interval.</p><p>*Subgroup analysis was performed in a random-effects model.</p><p>^#Exclusion of the study conducted by Jian, et al. yielded a pooled risk ratio: 0.97(95%CI:0.83–1.00, p = 0.04) with no heterogeneity among the remaining studies(I² = 0.0%,p = 0.65).</p><p>Subgroup analysis regarding the association between carotenoids consumption and PCa risk.</p

Enhanced Green Fluorescent Protein Transgenic Expression <i>In Vivo</i> Is Not Biologically Inert

Enhanced green fluorescent protein (EGFP) is a widely used biological reporter. However, the effects of EGFP expression <i>in vivo</i> are still unclear. To investigate the effects of EGFP transgenic expression <i>in vivo</i>, we employed an NMR-based metabonomics method to analyze the metabonome of EGFP transgenic mice. The results show that the metabonomes of urine, liver, and kidney of the EGFP transgenic mice are different from their wild-type counterparts. The EGFP mice expressed high levels of urinary 3-ureidopropionate, which is due to the down-regulated transcriptional level of β-ureidopropionase. The expression of EGFP <i>in vivo</i> also affects other metabolic pathways, including nucleic acid metabolism, energy utilization, and amino acids catabolism. These findings indicate that EGFP transgenic expression is not as inert as has been considered. Our investigation provides a holistic view on the effect of EGFP expression <i>in vivo</i>, which is useful when EGFP is employed as a functional biological indicator. Our work also highlights the potential of a metabonomics strategy in studying the association between molecular phenotypes and gene function

Research on the kinetics and degradation pathways of gaseous acetic acid ester organics

Designed to meet the specific needs of the printing industry exhaust gas emissions, this paper proposes a method for the degradation of gaseous acetic acid ester organics that is environmentally friendly, safe, and simple to use: micro-nano cavitation technology. In the process of using micro-nano cavitation technology to degrade acetic acid ester organics, the products in the degradation process were analyzed by gas chromatography-mass (GC-MS) spectrometry, and the degradation pathways of acetic acid ester organics were identified. Under high temperatures and high pressure caused by cavitation collapse, the C–C bond and C–O bond on the main chain of organic matter are cleaved to form low molecular products. Low-molecular intermediate products are continuously produced as the reaction advances, and these intermediate products are further oxidized and decomposed into carbon dioxide and water. Besides, the factors that influence the degradation rate of acetic acid ester organics were investigated. Based on the experimental data, acetic acid esters can degrade with the greatest efficiency when their initial concentration is 200 ± 50 mg/m3 and their treatment time is 20∼30 min. Moreover, the experiment was optimized using the response surface method. The results suggested that for an initial concentration of 155.544 mg/m3 and a reaction time of 21.961 min, the best degradation rate was 0.251 min−1. Micro-nano cavitation technology is a novel and promising technology for the degradation of volatile organic compounds, with a wide range of practical applications.</p