143 research outputs found

    Determination of Phenolic Acids and Flavonoids in Taraxacum formosanum Kitam by Liquid Chromatography-Tandem Mass Spectrometry Coupled with a Post-Column Derivatization Technique

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    A liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed for the determination of phenolic acids and flavonoids in a medicinal Chinese herb Taraxacum formosanum Kitam. Initially, both phenolic acids and flavonoids were extracted with 50% ethanol in a water-bath at 60 °C for 3 h and eventually separated into acidic fraction and neutral fraction by using a C18 cartridge. A total of 29 compounds were separated within 68 min by employing a Gemini C18 column and a gradient solvent system of 0.1% formic acid and acetonitrile at a flow rate of 1.0 mL/min. Based on the retention behavior as well as absorption and mass spectra, 19 phenolic acids and 10 flavonoids were identified and quantified in T. formosanum, with the former ranging from 14.1 μg/g to 10,870.4 μg/g, and the latter from 9.9 μg/g to 325.8 μg/g. For further identification of flavonoids, a post-column derivatization method involving shift reagents such as sodium acetate or aluminum chloride was used and the absorption spectral characteristics without or with shift reagents were compared. An internal standard syringic acid was used for quantitation of phenolic acids, whereas (±) naringenin was found suitable for quantitation of flavonoids. The developed LC-MS/MS method showed high reproducibility, as evident from the relative standard deviation (RSD) values for intra-day and inter-day variability being 1.0–6.8% and 2.0–7.7% for phenolic acids and 3.7–7.4% and 1.5–8.1% for flavonoids, respectively, and thus may be applied for simultaneous determination of phenolic acids and flavonoids in Chinese herb and nutraceuticals

    Integral Kinetic Model for Studying Quercetin Degradation and Oxidation as Affected by Cholesterol During Heating

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    The degradation and oxidation of quercetin, as affected by cholesterol during heating at 150 °C, was kinetically studied using non-linear regression models. Both TLC and HPLC were used to monitor the changes of quercetin, cholesterol and cholesterol oxidation products (COPs) during heating. The formation of COPs, including triol, 7-keto, 7α-OH and 7β-OH, was completely inhibited during the initial 30 minute heating period in the presence of 0.02% quercetin, accompanied by reduction in cholesterol peroxidation and degradation. However, the quercetin degradation or oxidation proceeded fast, with the rate constants (h−1) in the presence of nitrogen, oxygen and the combination of oxygen and cholesterol being 0.253, 0.868 and 7.17, respectively. When cholesterol and quercetin were heated together, the rate constants (h−1) of cholesterol peroxidation, epoxidation and degradation were 1.8 × 10−4, 0.016 and 0.19, respectively. The correlation coefficients (r2) for all the oxidative and degradation reactions ranged from 0.82–0.99. The kinetic models developed in this study may be used to predict the degradation and oxidation of quercetin as affected by cholesterol during heating

    Understanding of colistin usage in food animals and available detection techniques: a review

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    Progress in the medical profession is determined by the achievements and effectiveness of new antibiotics in the treatment of microbial infections. However, the development of multiple-drug resistance in numerous bacteria, especially Gram-negative bacteria, has limited the treatment options. Due to this resistance, the resurgence of cyclic polypeptide drugs like colistin remains the only option. The drug, colistin, is a well-known growth inhibitor of Gram-negative bacteria like Acinetobacter baumanni, Enterobacter cloacae, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Technological advancements have uncovered the role of the mcr-1(mobilized colistin resistance) gene, which is responsible for the development of resistance in Gram-negative bacteria, which make them distinct from other bacteria without this gene. Additionally, food animals have been determined to be the reservoir for colistin resistance microbes, from which they spread to other hosts. Due to the adverse effects of colistin, many developed countries have prohibited its usage in animal foods, but developing countries are still using colistin in animal food production, thereby imposing a major risk to the public health. Therefore, there is a need for implementation of sustainable measures in livestock farms to prevent microbial infection. This review highlights the negative effects (increased resistance) of colistin consumption and emphasizes the different approaches used for detecting colistin in animal-based foods as well as the challenges associated with its detectio

    Large-scale whole-exome sequencing association studies identify rare functional variants influencing serum urate levels

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    Elevated serum urate levels can cause gout, an excruciating disease with suboptimal treatment. Previous GWAS identified common variants with modest effects on serum urate. Here we report large-scale whole-exome sequencing association studies of serum urate and kidney function among ≤19,517 European ancestry and African-American individuals. We identify aggregate associations of low-frequency damaging variants in the urate transporters SLC22A12 (URAT1; p = 1.3 × 10-56) and SLC2A9 (p = 4.5 × 10-7). Gout risk in rare SLC22A12 variant carriers is halved (OR = 0.5, p = 4.9 × 10-3). Selected rare variants in SLC22A12 are validated in transport studies, confirming three as loss-of-function (R325W, R405C, and T467M) and illustrating the therapeutic potential of the new URAT1-blocker lesinurad. In SLC2A9, mapping of rare variants of large effects onto the predicted protein structure reveals new residues that may affect urate binding. These findings provide new insights into the genetic architecture of serum urate, and highlight molecular targets in SLC22A12 and SLC2A9 for lowering serum urate and preventing gout

    New genetic loci link adipose and insulin biology to body fat distribution.

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    Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

    Pigmentation potency of turf Bermuda grass with analysis of carotenoids in egg yolks

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    Typescript (photocopy).Four experiments were performed to evaluate the potential of using turf Bermuda grass as a pigmenting agent for laying hens. In experiment 1, the carotene and xanthophyll changes during growth of turf Bermuda grass (Cynodon dactylon) were monitored every three days for a total of 18 days. The carotene and xanthophyll concentrations were not proportional to age or length of the grass clippings. Several methods of processing raw turf Bermuda grass to feed-grade materials were also evaluated. Freeze-drying was by far the best method to maintain the maximum carotene and xanthophyll concentrations. Field drying resulted in considerable losses of both carotene and xanthophyll concentrations. In experiment 2, the effect of diets containing various levels of dehydrated turf Bermuda grass on egg production, feed utilization, yolk color and egg weight was studied. Milo-soybean meal diets were formulated into 4 treatments containing 0, 3, 6 and 9% dried turf Bermuda grass. After 4 weeks the average Roche color score was 1.3, 4.9, 7.0 and 8.7 for treatments 1 through 4, respectively. The maximum egg production and minimum feed consumption were observed in diets containing 3% turf Bermuda grass meal. There was no significant difference of egg weight between control and grass-fed treatments. In experiment 3, the deposition of xanthophylls in egg yolks from laying hens fed 9% turf Bermuda grass meal was studied. The various carotenoids present in egg yolks were analyzed by open-column, thin-layer and high-performance liquid chromatography (HPLC). Chromatographic analyses suggest that the yolk color was due mainly to the presence of free lutein and zeaxanthin at a ratio of 79:21 respectively. In experiment 4, a simple, rapid HPLC method was developed to separate and quantify the major carotenoids present in turf Bermuda grasses with minimum isomerization and oxidation. A reversed-phase isocratic solvent system of water-acetonitrile-chloroform (2:83:15) provided a clear separation of neoxanthin, violaxanthin, lutein and β-carotene. Separation occurred within 10 min with detection at 470 nm and a sensitivity at 0.01 a.u.f.s. This method was found to be very reproducible with coefficients of variation less than 3% in 5 sample analyses

    Biotype determination and a study of the selective interaction between the Hessian fly, Mayetiola destructor (Say), and wheat, Triticum aestivum L. em Thell

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    Fifteen collections of Hessian fly from the northern portion of the soft winter wheat region were used to determine the biotype composition and frequency. Biotypes J and L were found to have replaced biotype B as the prevalent biotypes in Indiana since wheat cultivars carrying the H5 and the H6 genes have been grown. Biotype GP, the least virulent of the known biotypes of Hessian fly, was identified in New York indicating that cultivars with no genes for resistance are still being grown there. Experiments were conducted to determine the interaction between wheats having the H6 gene and Hessian fly biotype M. By definition, biotype M should not survive on wheats having the H6 gene. Auburn, Caldwell, Fillmore, and Knox 62, cultivars all having the H6 gene for resistance, were exposed to Hessian fly biotype M. Reactions to biotype M were significantly different among the cultivars. The selection experiments showed that resistance of Auburn and Fillmore could be easily overcome. Selection on wheats having the H6 gene resulted in a biotype derived from biotype M, capable of surviving on wheats having the H6 gene. This new biotype selected on specific cultivars with the H6 gene differed depending on the cultivar used for selection. Results showed that Knox 62 was consistently different from the other three cultivars used in this study because it probably possesses the H6, the H7H8 and Kawvale genes. Therefore, Knox 62 should not be used as the H6 gene source as a differential cultivar. The responses of this new biotype to wheats having the H9, H9H10, H12, and H13 genes were determined. Results showed that this new biotype possesses virulence on wheats having the H9, H12, and H13 genes. The flies have linked virulence for the H6, H9, H12, and H13 genes
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