Chemical composition and anti-biofilm activity of burdock (Arctium lappa L Asteraceae) leaf fractions against Staphylococcus aureus

Purpose: To determine the chemical composition and anti-biofilm activity of burdock leaf fractions against Staphylococcus aureusMethods: The anti-biofilm activity of burdock leaf fractions obtained by column chromatography against S. aureus was determined by minimum inhibitory concentration (MIC). Scanning electron microscopy was employed to further investigate the inhibitory activity. Analysis of the chemical composition of the fractions was performed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS).Results: The 20 and 34 % ethanol fractions each inhibited the formation of biofilm by S. aureus, with half maximal inhibitory concentration (IC50) ranging from 110 to 150 μg/ml. The 70 % ethanol elution fraction exhibited the strongest inhibitory activity against biofilm formation with IC50 of 13 μg/ml. The minimum inhibitory concentration of the 70 % ethanol fraction completely inhibited the formation of biofilm at a concentration of 0.5 mg/ml, which was lower than the MIC for the growth of the test bacterium (1.25 mg/ml). Scanning electron microscopy (SEM) showed that there was no biofilm formation for cultures treated with burdock leaf fraction, thus confirming the inhibitory efficiency of burdock leaf fraction against biofilm formation. UPLC-MS data identified five active compounds, namely, :caffeic acid, p-coumaric acid, cynarin, quercetin and luteolin.Conclusion: The biofilm formation inhibitory effect of burdock leaf was not only due to its inhibitory effect on bacterial growth but appear to be influenced by its effect on bacterial surface hydrophobicity, and aggregation. Thus, the leaf fractions may be useful in the control of biofilms.Keywords: Biofilm, Staphylococcus aureus, Arctium lappa, Burdock leaf, Scanning electron microscope, Ultra-performance liquid chromatography-mass spectrometr

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Alignment determination of symmetric top molecule using rotationally resolved LIF

This payer presents a concrete theoretical treatment which can be used for transforming the laser-induced fluorescence (LIF) intensity into the population and alignment parameters of a symmetric top molecule, The molecular population and alignment are described by molecular state multipoles. The results are presented in a general excitation-detection geometry and then specialized in some special geometries. The problem how to extract the initial molecular state multipoles from the rotationally resolved LIF intensity is discussed in detail. (C) 1999 Elsevier Science B.V. All rights reserved

POLARIZED BAO-STAR EMISSION FROM THE REACTION BA(S-1,D-3)+N2O

Woodward Girl Scouts performing the Garland dance at the May fete, May 3, 1924

Angular axis distribution of asymmetric top molecules by the absorption of plane and circularly polarized light

Expressions used for describing optical preparation of aligned and oriented reagents are derived. The plane polarized light can only be used to control the alignment of reagents, and the circularly polarized light can be used to control the alignment and orientation of reagents. For asymmetric top molecules, the degree of align ment can often be chosen to be high, and the degree of orientation is often low. Specially, if reagents are symmetric top molecules, both degrees of alignment and orientation can often be chosen to be high for the K-selected state

LASER-INDUCED FLUORESCENCE STUDY OF THE BEAM-GAS REACTIONS OF BA WITH O,M,P-C6H4CL2

The exothermic abstraction reactions Ba + R - Cl (R = o-, m- and p-C6H4Cl) have been studied using the laser-induced fluorescence method in a beam-gas arrangement. A modified statistical model based on Marcus has been proposed to calculate the distributions of internal energy states of the product molecules. The experimental results are well reproduced by the calculated ones that assume that only a few vibrational modes in the collision complexes participate in intramolecular energy redistribution

COMPARISON OF THE DYNAMICS OF THE REACTIONS OF BA WITH AROMATIC HALIDES AND ALKYL-HALIDES - LIF STUDIES OF THE REACTIONS OF BA WITH C6H5X (X=CL, BR, I)

Nascent internal state energy distributions of BaX have been studied for the reactions Ba+C6H5X --> BaX+C6H5 (X=Cl, Br, I) using the laser-induced fluorescence method in a beam-gas arrangement. The energy disposal differs markedly from that of the reactions Ba+CH3X. With the change of X from Cl to I, the vibrational excitations and the reactive cross sections decrease for the reactions Ba+C6H5X, whereas those of the reactions Ba+CH3X increase. The CNDO/2 calculations of C6H5X and CH3X have been used to interpret the experimental results qualitatively