Vacuum-powered bubble-assisted solvent extraction followed by macroporous resin enrichment for isolation of podophyllotoxin from Sinopodophyllum em...
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2015 Oct 1;. doi: 10.1016/j.jchromb.. Epub
2015 Sep 3.Vacuum-powered bubble-assisted solvent extraction followed by macroporous resin enrichment for isolation of podophyllotoxin from Sinopodophyllum emodi.1, 2, 3, 1, 1, 1, 1, 1.1College of Pharmacy, Qiqihar Medical University, 161006 Qiqihar, China.2Key Laboratory of Forest Plant Ecology, Northeast Forestry University, 150040 Harbin, China.3College of Pharmacy, Qiqihar Medical University, 161006 Qiqihar, China. Electronic address: .AbstractA vacuum-powered bubble-assisted solvent extraction (VBE) technique was used to extract podophyllotoxin from the root of Sinopodophyllum emodi. We optimized the VBE procedure and showed it had the highest efficiency of extraction compared to other conventional extraction techniques. Based upon the results of single-factor experiments, a three-factor, three-level experiment design was developed by application of a Box-Behnken design. The method was validated by stability, repeatability and recovery experiments. The optimal conditions were: solvent, 60% (v/v) particle size of the sample, 60-80 soak time, 2h; liquid/solid ratio, 21L/ air flow, 32mL/ vacuum-powered bubble extraction time, 65min. The VBE method we developed achieved efficient extraction of podophyllotoxin from S. emodi. The podophyllotoxin extracted can be enriched and separated by an HPD300 macroporous resin adsorption and desorption process. The results indicated that VBE is a convenient, rapid and efficient sample preparation technique. Copyright (C) 2015 Elsevier B.V. All rights reserved.KEYWORDS: M P Response S Vacuum-powered bubble-assisted solvent extractionPMID:
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External link. Please review our .Competitive lithium solvation of linear and cyclic carbonates from quantum chemistry.
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2016 Jan 7;18(1):164-75. doi: 10.121e. Epub
2015 Nov 25.Competitive lithium solvation of linear and cyclic carbonates from quantum chemistry.1, , , , , .1Electrochemistry Branch, RDRL-SED-C, US Army Research Laboratory, 2800 Powder Mill Rd., Adelphi, MD, , USA. oleg.a.borodin.civ@mail.mil.AbstractThe composition of the lithium cation (Li(+)) solvation shell in mixed linear and cyclic carbonate-based electrolytes has been re-examined using Born-Oppenheimer molecular dynamics (BOMD) as a function of salt concentration and cluster calculations with ethylene carbonate:dimethyl carbonate (EC:DMC)-LiPF6 as a model system. A coordination preference for EC over DMC to a Li(+) was found at low salt concentrations, while a slightly higher preference for DMC over EC was found at high salt concentrations. Analysis of the relative binding energies of the (EC)n(DMC)m-Li(+) and (EC)n(DMC)m-LiPF6 solvates in the gas-phase and for an implicit solvent (as a function of the solvent dielectric constant) indicated that the DMC-containing Li(+) solvates were stabilized relative to (EC4)-Li(+) and (EC)3-LiPF6 by immersing them in the implicit solvent. Such stabilization was more pronounced in the implicit solvents with a high dielectric constant. Results from previous Raman and IR experiments were reanalyzed and reconciled by correcting them for changes of the Raman activities, IR intensities and band shifts for the solvents which occur upon Li(+) coordination. After these correction factors were applied to the results of BOMD simulations, the composition of the Li(+) solvation shell from the BOMD simulations was found to agree well with the solvation numbers extracted from Raman experiments. Finally, the mechanism of the Li(+) diffusion in the dilute (EC:DMC)LiPF6 mixed solvent electrolyte was studied using the BOMD simulations. PMID:
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External link. Please review our .Structural and functional profiling of the human histone methyltransferase SMYD3.
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):e22290. doi: 10.1371/journal.pone.0022290. Epub
2011 Jul 14.Structural and functional profiling of the human histone methyltransferase SMYD3.1, , , , , , , , , , .1OSI Pharmaceuticals, Inc., Farmingdale, New York, United States of America. AbstractThe SET and MYND Domain (SMYD) proteins comprise a unique family of multi-domain SET histone methyltransferases that are implicated in human cancer progression. Here we report an analysis of the crystal structure of the full length human SMYD3 in a complex with an analog of the S-adenosyl methionine (SAM) methyl donor cofactor. The structure revealed an overall compact architecture in which the "split-SET" domain adopts a canonical SET domain fold and closely assembles with a Zn-binding MYND domain and a C-terminal superhelical 9 α-helical bundle similar to that observed for the mouse SMYD1 structure. Together, these structurally interlocked domains impose a highly confined binding pocket for histone substrates, suggesting a regulated mechanism for its enzymatic activity. Our mutational and biochemical analyses confirm regulatory roles of the unique structural elements both inside and outside the core SET domain and establish a previously undetected preference for trimethylation of H4K20.PMID:
[PubMed - indexed for MEDLINE] (A) Linear representation of domain structures of SMYDs1–5. The split SET domain is shown in red (N-SET) and tan (C-SET); the MYND domain is represented in yellow and the cysteine-rich post-SET domain is displayed in pale green. Starting and ending amino acids are indicated. (B) Ribbon representation of the structure of SMYD3-Sinefungin at 1.85? resolution in cross-eye stereo. The SET domain of SMYD3 is split into the N-SET (red) and the C-SET (tan) by an intervening MYND domain (yellow) and a Rubisco-LSMT-like I-SET region (cyan). The post-SET motif (pale green) precedes a long (~150 residue) C-terminal domain (CTD, blue). Positions of Sinefungin (green carbons) and zinc atoms (spheres) are indicated.PLoS One. ):e22290.(A, B) SMYD3 purified from baculovirus methylates all histones (H4&&H2A&H3&H2B) in vitro. Histone methyltransferase (HMTase) assays employed mixed histones from HeLa cells as substrate. Upper panel, fluorography showing 3H-incorporation into H3 (17 kD) and into species smaller bands (H2A/H2B and H4). Lower panel, Coomassie-stained SDS-PAGE gel used to verify equal loading. (C) SMYD3 purified from bacteria methylates histones H4&&H3&H2A in vitro. Recombinant histones or mixed histones were used, as indicated, for substrate. Fluorography is shown and the bands corresponding to each histone are indicated.PLoS One. ):e22290.(A) SMYD3 trimethylates H4-K20. Right panel: unmethylated [H4(0)], mono-[H4(1)], di-[H4(2)], and, as a negative control, tri-methylated [H4(3)] peptides were employed in an in vitro HMTase proximity bead assay with baculoviral SMYD3 and SMYD1 (negative control). Degree of methylation was measured by scintillation counting in CPM. Left panels: Western analysis using anti-mono- and trimethyl-specific antibodies (Upstate) confirm in vitro specificity of SMYD3 for H4-K20me3. (B) SMYD3 preferentially trimethylates H4-K20 in reconstituted chromatin. Recombinant oocyte nucelosomes were assembled into chromatin, followed by in vitro HMTase assays and SDS-PAGE resolution of reaction products. SMYD3 inputs were increased from 0.5 ug to 2.4 ug, (triangle above lanes), and western analyses were performed with the indicated histone H4 methylation state-specific antibodies (middle panels), with a pan-anti-H4 (lower panel) providing a loading control for chromatin input.PLoS One. ):e22290.(A) Wild-type SMYD3, but not catalytic point mutant Y239F, methylates recombinant H3 and H4 in an in vitro HMTase assay. Upper panels: Fluorographs with bands corresponding to H3 (left) and H4 (right) indicated. Lower panels: Coomassie-stained PVDF membranes used to verify equal loading. (B) Substitution and (C) truncation mutants, constructed in E coli as described in Methods, were compared in in vitro HMTase assays to wildtype SMYD3 and to SET7/9. Inputs (upper panels, ~500 ng) were assayed for 3H-SAM incorporation (middle panels) either on recombinant histone 4 or mixed histones, as indicated (lower panels). Alanine substitutions of most SMYD3 residues predicted to be catalytically essential eliminate HMTase activities. An exception is T184/A which, as described in the text, appears to affect H3-H4 substrate specificity (note change in relative ratios of H3/H4). N-terminal truncation through position 44 removes the entire N-SET domain, while truncation through position 74 eliminates both the N-SET domain and half the MYND domain.PLoS One. ):e22290.The peptide, colored black, and with backbone traced in green ribbon, was taken from an overlay with the SET9 ternary structure. (A) Ribbon representation of the ternary complex. Substrate methyl donor and peptide are indicated as green wire bonds and ribbons, respectively. Domain colors for SMYD3 correspond to those in Fig. 1. The aromatic cage residues (Y239, F183) at the end of the lysine channel are shown explicitly. (B) Overlay of SMYD1 (magenta, PDB accession #3N71) and SMYD3 (colored by domain) proteins in the ternary model. Numbering of residues is for SMYD3.PLoS One. ):e22290.In vitro assays were carried out using bacterially expressed/purified 6XHis-SMYDs and recombinant H3 (top and lower, respectively, Coomassie-stain panels). Center panel: Autoradiography of the anti-H3-K4me3 (UpState) western blot.PLoS One. ):e22290.(A) N-CoR co-immunoprecipitates with wildtype SMYD3 but not with SMYD3 MYND domain point mutant C49/S. 293T cells were co-transfected with N-CoR, N-terminal myc-tagged SMYD3 constructs indicated, and with empty vector (vector). 48 hours post-transfection, whole cell RIPA lysates (WCL) were prepared. Fractions of the lysates were subjected to anti-N-CoR co-immunoprecipitation and the remaining 50% served as input. Western analysis was performed with anti-myc antibodies. Myc-SMYD1B, previously shown to interact with N-CoR served as a positive control. (B) Schematic of GAL4-DNA binding domain (DBD) and GAL4-fusion constructs for wild type (GAL4-SMYD3) and MYND domain-mutated (GAL4-SMYD3-C49/S) two hybrid transcription assays. X denotes the location of the C49/S mutation. (C) GAL4-SMYD3 but not GAL4-SMYD3-C49/S represses transcription of a GAL4-UAS containing luciferase reporter. 293T cells were transiently co-transfected with the 5XGAL4-SV40-luciferase reporter (1 ug) together with GAL4-DBD, or with 1 or 2 ug (indicated as 1X or 2X) of GAL4-SMYD3 (black bars) or GAL4-SMYD3-C49/S (red bars). Transfection efficiencies were normalized to co-transfected renilla luciferase, and percent GAL4 activity was determined in relation to GAL4-DBD set at 100%.PLoS One. ):e22290.Comparison of the CTD orientations in SMYD1 (magenta) and SMYD3 in cross-eye stereo. The larger loop structure in SMYD1 (indicated by the arrow) forces the CTD assembly to shift such that the C-terminus no longer contacts the MYND domain, as in SMYD3. The contacts between the two domains lie within the red circle.PLoS One. ):e22290.Publication TypesMeSH TermsSubstancesGrant SupportFull Text SourcesOther Literature SourcesMiscellaneous
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External link. Please review our .Development and Validation of Search Filters to Identify Articles on Family Medicine in Online Medical Databases.
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2015 Jul-A13(4):364-6. doi: 10.1370/afm.1780.Development and Validation of Search Filters to Identify Articles on Family Medicine in Online Medical Databases.1, 2, 3, 4, 3.1Department of Family Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands d.pols@erasmusmc.nl.2Medical Library, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.3Department of Family Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.4Department of Primary and Community Care, Radboud University Medical Center, Nijmegen, The Netherlands.AbstractPhysicians and researchers in the field of family medicine often need to find relevant articles in online medical databases for a variety of reasons. Because a search filter may help improve the efficiency and quality of such searches, we aimed to develop and validate search filters to identify research studies of relevance to family medicine. Using a new and objective method for search filter development, we developed and validated 2 search filters for family medicine. The sensitive filter had a sensitivity of 96.8% and a specificity of 74.9%. The specific filter had a specificity of 97.4% and a sensitivity of 90.3%. Our new filters should aid literature searches in the family medicine field. The sensitive filter may help researchers conducting systematic reviews, whereas the specific filter may help family physicians find answers to clinical questions at the point of care when time is limited. (C) 2015 Annals of Family Medicine, Inc.KEYWORDS: bib information s search filtersPMID:
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