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Find video protocols related to scientific articles indexed in Pubmed.
Phylogenomics resolves the timing and pattern of insect evolution.
Bernhard Misof, Shanlin Liu, Karen Meusemann, Ralph S Peters, Alexander Donath, Christoph Mayer, Paul B Frandsen, Jessica Ware, Tomáš Flouri, Rolf G Beutel, Oliver Niehuis, Malte Petersen, Fernando Izquierdo-Carrasco, Torsten Wappler, Jes Rust, Andre J Aberer, Ulrike Aspöck, Horst Aspöck, Daniela Bartel, Alexander Blanke, Simon Berger, Alexander Böhm, Thomas R Buckley, Brett Calcott, Junqing Chen, Frank Friedrich, Makiko Fukui, Mari Fujita, Carola Greve, Peter Grobe, Shengchang Gu, Ying Huang, Lars S Jermiin, Akito Y Kawahara, Lars Krogmann, Martin Kubiak, Robert Lanfear, Harald Letsch, Yiyuan Li, Zhenyu Li, Jiguang Li, Haorong Lu, Ryuichiro Machida, Yuta Mashimo, Pashalia Kapli, Duane D McKenna, Guanliang Meng, Yasutaka Nakagaki, José Luis Navarrete-Heredia, Michael Ott, Yanxiang Ou, Günther Pass, Lars Podsiadlowski, Hans Pohl, Björn M von Reumont, Kai Schütte, Kaoru Sekiya, Shota Shimizu, Adam Slipinski, Alexandros Stamatakis, Wenhui Song, Xu Su, Nikolaus U Szucsich, Meihua Tan, Xuemei Tan, Min Tang, Jingbo Tang, Gerald Timelthaler, Shigekazu Tomizuka, Michelle Trautwein, Xiaoli Tong, Toshiki Uchifune, Manfred G Walzl, Brian M Wiegmann, Jeanne Wilbrandt, Benjamin Wipfler, Thomas K F Wong, Qiong Wu, Gengxiong Wu, Yinlong Xie, Shenzhou Yang, Qing Yang, David K Yeates, Kazunori Yoshizawa, Qing Zhang, Rui Zhang, Wenwei Zhang, Yunhui Zhang, Jing Zhao, Chengran Zhou, Lili Zhou, Tanja Ziesmann, Shijie Zou, Yingrui Li, Xun Xu, Yong Zhang, Huanming Yang, Jian Wang, Jun Wang, Karl M Kjer, Xin Zhou.
Science
PUBLISHED: 11-06-2014
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Insects are the most speciose group of animals, but the phylogenetic relationships of many major lineages remain unresolved. We inferred the phylogeny of insects from 1478 protein-coding genes. Phylogenomic analyses of nucleotide and amino acid sequences, with site-specific nucleotide or domain-specific amino acid substitution models, produced statistically robust and congruent results resolving previously controversial phylogenetic relations hips. We dated the origin of insects to the Early Ordovician [~479 million years ago (Ma)], of insect flight to the Early Devonian (~406 Ma), of major extant lineages to the Mississippian (~345 Ma), and the major diversification of holometabolous insects to the Early Cretaceous. Our phylogenomic study provides a comprehensive reliable scaffold for future comparative analyses of evolutionary innovations among insects.
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Releasing Metal Catalysts via Phase Transition: (NiO)0.05-(SrTi0.8Nb0.2O3)0.95 as a Redox Stable Anode Material for Solid Oxide Fuel Cells.
ACS Appl Mater Interfaces
PUBLISHED: 10-22-2014
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Donor-doped perovskite-type SrTiO3 experiences stoichiometric changes at high temperatures in different Po2 involving the formation of Sr or Ti-rich impurities. NiO is incorporated into the stoichiometric strontium titanate, SrTi0.8Nb0.2O3-? (STN), to form an A-site deficient perovskite material, (NiO)0.05-(SrTi0.8Nb0.2O3)0.95 (Ni-STN), for balancing the phase transition. Metallic Ni nanoparticles can be released upon reduction instead of forming undesired secondary phases. This material design introduces a simple catalytic modification method with good compositional control of the ceramic backbones, by which transport property and durability of solid oxide fuel cell anodes are largely determined. Using Ni-STN as anodes for solid oxide fuel cells, enhanced catalytic activity and remarkable stability in redox cycling have been achieved. Electrolyte-supported cells with the cell configuration of Ni-STN-SDC anode, La0.8Sr0.2Ga0.87Mg0.13O3 (LSGM) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode produce peak power densities of 612, 794, and 922 mW cm(-2) at 800, 850, and 900 °C, respectively, using H2 as the fuel and air as the oxidant. Minor degradation in fuel cell performance resulted from redox cycling can be recovered upon operating the fuel cells in H2. Such property makes Ni-STN a promising regenerative anode candidate for solid oxide fuel cells.
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Native and Thermally Modified Protein-Polyphenol Coassemblies: Lactoferrin-Based Nanoparticles and Submicrometer Particles as Protective Vehicles for (-)-Epigallocatechin-3-gallate.
J. Agric. Food Chem.
PUBLISHED: 10-21-2014
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The interactions between native, thermally modified lactoferrin (LF) and (-)-epigallocatechin-3-gallate (EGCG) at pH 3.5, 5.0, and 6.5 were investigated. Turbidity, particle size, and charge of LF-EGCG complexes were mainly dominated by pH value and secondary structure of protein. At pH 3.5 and 5.0, LF-EGCG complexes were nanoparticles which had high ?-potential, small size, and soluble state. At pH 6.5, they were submicrometer particles which exhibited low ?-potential, large size, and insoluble state. The infrared spectra of freeze-dried LF-EGCG complexes showed that they were different from LF and EGCG alone. Far-UV CD results indicated that heat denaturation might irreversibly alter the secondary structure of LF and EGCG induced a progressive increase in the proportion of ?-helix structure at the cost of ?-sheet and unordered coil structure of LF at pH 3.5, 5.0, and 6.5. EGCG exhibited a strong affinity for native LF but a weak affinity for thermally modified LF at pH 5.0 and 6.5. An inverse result was observed at pH 3.5. These results could have potential for the development of food formulations based on LF as a carrier of bioactive compounds.
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Suppression of subtelomeric VSG switching by Trypanosoma brucei TRF requires its TTAGGG repeat-binding activity.
Nucleic Acids Res.
PUBLISHED: 10-13-2014
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Trypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, VSG, in the bloodstream of its mammalian host to evade the host immune response. VSGs are expressed exclusively from subtelomeric loci, and we have previously shown that telomere proteins TbTIF2 and TbRAP1 play important roles in VSG switching and VSG silencing regulation, respectively. We now discover that the telomere duplex DNA-binding factor, TbTRF, also plays a critical role in VSG switching regulation, as a transient depletion of TbTRF leads to significantly more VSG switching events. We solved the NMR structure of the DNA-binding Myb domain of TbTRF, which folds into a canonical helix-loop-helix structure that is conserved to the Myb domains of mammalian TRF proteins. The TbTRF Myb domain tolerates well the bulky J base in T. brucei telomere DNA, and the DNA-binding affinity of TbTRF is not affected by the presence of J both in vitro and in vivo. In addition, we find that point mutations in TbTRF Myb that significantly reduced its in vivo telomere DNA-binding affinity also led to significantly increased VSG switching frequencies, indicating that the telomere DNA-binding activity is critical for TbTRF's role in VSG switching regulation.
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Beclin 1 is required for neuron viability and regulates endosome pathways via the UVRAG-VPS34 complex.
PLoS Genet.
PUBLISHED: 10-01-2014
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Deficiency of autophagy protein beclin 1 is implicated in tumorigenesis and neurodegenerative diseases, but the molecular mechanism remains elusive. Previous studies showed that Beclin 1 coordinates the assembly of multiple VPS34 complexes whose distinct phosphatidylinositol 3-kinase III (PI3K-III) lipid kinase activities regulate autophagy at different steps. Recent evidence suggests a function of beclin 1 in regulating multiple VPS34-mediated trafficking pathways beyond autophagy; however, the precise role of beclin 1 in autophagy-independent cellular functions remains poorly understood. Herein we report that beclin 1 regulates endocytosis, in addition to autophagy, and is required for neuron viability in vivo. We find that neuronal beclin 1 associates with endosomes and regulates EEA1/early endosome localization and late endosome formation. Beclin 1 maintains proper cellular phosphatidylinositol 3-phosphate (PI(3)P) distribution and total levels, and loss of beclin 1 causes a disruption of active Rab5 GTPase-associated endosome formation and impairment of endosome maturation, likely due to a failure of Rab5 to recruit VPS34. Furthermore, we find that Beclin 1 deficiency causes complete loss of the UVRAG-VPS34 complex and associated lipid kinase activity. Interestingly, beclin 1 deficiency impairs p40phox-linked endosome formation, which is rescued by overexpressed UVRAG or beclin 1, but not by a coiled-coil domain-truncated beclin 1 (a UVRAG-binding mutant), Atg14L or RUBICON. Thus, our study reveals the essential role for beclin 1 in neuron survival involving multiple membrane trafficking pathways including endocytosis and autophagy, and suggests that the UVRAG-beclin 1 interaction underlies beclin 1's function in endocytosis.
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Polarity mechanisms such as contact inhibition of locomotion regulate persistent rotational motion of mammalian cells on micropatterns.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 09-25-2014
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Pairs of endothelial cells on adhesive micropatterns rotate persistently, but pairs of fibroblasts do not; coherent rotation is present in normal mammary acini and kidney cells but absent in cancerous cells. Why? To answer this question, we develop a computational model of pairs of mammalian cells on adhesive micropatterns using a phase field method and study the conditions under which persistent rotational motion (PRM) emerges. Our model couples the shape of the cell, the cell's internal chemical polarity, and interactions between cells such as volume exclusion and adhesion. We show that PRM can emerge from this minimal model and that the cell-cell interface may be influenced by the nucleus. We study the effect of various cell polarity mechanisms on rotational motion, including contact inhibition of locomotion, neighbor alignment, and velocity alignment, where cells align their polarity to their velocity. These polarity mechanisms strongly regulate PRM: Small differences in polarity mechanisms can create significant differences in collective rotation. We argue that the existence or absence of rotation under confinement may lead to insight into the cell's methods for coordinating collective cell motility.
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[Association study of CNR1, GAD1 and BDNF polymorphisms with male heroin dependence in the Dai population in Yunnan].
Yi Chuan
PUBLISHED: 09-25-2014
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In order to analyze the association of CNR1(Cannabinoid receptor 1), GAD1(Glutamate decarboxylase 1), and BDNF(Brain-derived neurotrophic factor) polymorphisms with male heroin dependence in the Dai population in Yunnan Province, an eight-SNP co-amplification protocol was established to genotype on the SNaPshot platform. A case-control study was performed with 8 SNPs from CNR1, GAD1, and BDNF genes in 165 heroin-dependent males and 170 healthy males of the Dai population. Statistical analyses were conducted with SPSS17.0, Haploview4.2, PHASE2.1, and MDR software. We found that: (1) the genotype frequency of rs13306221 was significant in the case group (P<0.025); (2) the A allelic frequency of rs6265 was significantly higher in the case group; (3) the haplotypes of T-A-C, C-C-C, C-C-T, and T-C-C based on rs1978340-rs3791878-rs11542313 and haplotype A-G based on rs6265-rs13306221 were significant (P<0.05); (4) the haplotype frequencies of T-A-C, C-C-T, and A-G were significantly higher in the case group. These results indicate that the linkage between rs1978340 and rs3791878 in GAD1 has a strong association with heroin dependence. Furthermore, polymorphisms in CNR1 (rs1049353), GAD1 (rs1978340 and rs11542313), and BDNF (rs6265 and rs13306221) were associated with heroin dependence in the Yunnan Dai population, and individuals with the rs6265 A allele were more likely to be heroin dependent.
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Pattern formation by phase-field relaxation of bending energy with fixed surface area and volume.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 09-17-2014
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We explore a wide variety of patterns of closed surfaces that minimize the elastic bending energy with fixed surface area and volume. To avoid complicated discretization and numerical instabilities for sharp surfaces, we reformulate the underlying constrained minimization problem by constructing phase-field functionals of bending energy with penalty terms for the constraints and develop stable numerical methods to relax these functionals. We report our extensive computational results with different initial surfaces. These results are discussed in terms of the reduced volume and are compared with the known results obtained using the sharp-interface approach. Finally, we discuss the implications of our numerical findings.
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Effects of milk proteins on release properties and particle morphology of ?-carotene emulsions during in vitro digestion.
Food Funct
PUBLISHED: 09-13-2014
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In the present study, ?-lactoglobulin, sodium caseinate, lactalbumin and lactoferrin were used to prepare ?-carotene emulsions. The milk protein-stabilized emulsions were explored using an in vitro release model to elucidate the effects of different milk proteins on ?-carotene release properties in the stomach, duodenum and small intestine, respectively. Notable changes in the droplet size and size distribution were observed among these four oil-in-water (O/W) milk protein emulsions. In the gastric environment, the highest ?-carotene release rate (2.9%) was achieved in ?-lactoglobulin emulsion with a remarkable change in the particle size. In the simulated intestine, the best ?-carotene micellarization potency (92%) was observed in ?-lactoglobulin emulsion and its droplet diameter moderately increased from 215 nm to 471 nm. Moreover, substantial release of ?-carotene was found in the small intestine for the four types of emulsions. It was concluded that ?-carotene release in different digestive stages was characterized by the emulsion interfacial composition.
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Perturbing the general base residue Glu166 in the active site of class A ?-lactamase leads to enhanced carbapenem binding and acylation.
Biochemistry
PUBLISHED: 08-15-2014
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Most class A ?-lactamases cannot hydrolyze carbapenem antibiotics effectively. The molecular mechanism of this catalytic inefficiency has been attributed to the unique stereochemistry of carbapenems, including their 6-?-hydroxyethyl side chain and the transition between two tautomeric states when bound at the active site. Previous studies have shown that the 6-?-hydroxyethyl side chain of carbapenems can interfere with catalysis by forming hydrogen bonds with the deacylation water molecule to reduce its nucleophilicity. Here our studies of a class A noncarbapenemase PenP demonstrate that substituting the general base residue Glu166 with Ser or other residues leads to a significant enhancement of the acylation kinetics by ?100-500 times toward carbapenems like meropenem. The structures of PenP and Glu166Ser both in apo form and in complex with meropenem reveal that Glu166 is critical for the formation of a hydrogen bonding network within the active site that locks Asn170 in an orientation to impose steric clash with the 6-?-hydroxyethyl side chain of meropenem. The Glu166Ser substitution weakens this network and enables Asn170 to adopt an alternative conformation to avoid steric clash and accommodate faster acylation kinetics. Furthermore, the weakened hydrogen bonding network caused by the Glu166Ser substitution allows the 6-?-hydroxyethyl moiety to adopt a catalytically favorable orientation as seen in class A carbapenemases. In summary, our data identify a previously unreported role of the universally conserved general base residue Glu166 in impeding the proper binding of carbapenems by restricting their 6-?-hydroxyethyl group.
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Structural investigation of ribosomally synthesized natural products by hypothetical structure enumeration and evaluation using tandem MS.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 08-04-2014
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Ribosomally synthesized and posttranslationally modified peptides (RiPPs) are a growing class of natural products that are found in all domains of life. These compounds possess vast structural diversity and have a wide range of biological activities, promising a fertile ground for exploring novel natural products. One challenging aspect of RiPP research is the difficulty of structure determination due to their architectural complexity. We here describe a method for automated structural characterization of RiPPs by tandem mass spectrometry. This method is based on the combined analysis of multiple mass spectra and evaluation of a collection of hypothetical structures predicted based on the biosynthetic gene cluster and molecular weight. We show that this method is effective in structural characterization of complex RiPPs, including lanthipeptides, glycopeptides, and azole-containing peptides. Using this method, we have determined the structure of a previously structurally uncharacterized lanthipeptide, prochlorosin 1.2, and investigated the order of the posttranslational modifications in three biosynthetic systems.
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Extremely low frequency electromagnetic field exposure causes cognitive impairment associated with alteration of the glutamate level, MAPK pathway activation and decreased CREB phosphorylation in mice hippocampus: reversal by procyanidins extracted from the lotus seedpo
Food Funct
PUBLISHED: 07-29-2014
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Lotus seedpod procyanidins (LSPCs) could effectively prevent learning and memory damage and oxidative damage caused by extremely low frequency electromagnetic field (ELF-EMF) exposure. However, LSPCs protect neurons from ELF-EMF-induced damage by mechanisms currently not clear. An excessive release of glutamate is considered to be one of the molecular mechanisms of neuronal damage in several neurological diseases. In this study we determined whether the ELF-EMF (50 Hz, 8 mT, 28 days) exposure induced alterations of glutamate release in mice hippocampus and explored the possible mechanism, and if LSPC treatment normalized its alterations. The results showed that ELF-EMF exposure induced the increased contents of glutamate, GABA, excessively activated NMDA receptors, increasing the number of NMDA receptor 2B (NR2B) and intracellular Ca(2+) concentration [Ca(2+)]i in hippocampus. In addition, ELF-EMF exposure decreased the ERK1/2 and CREB phosphorylation, which suggested that the Ca(2+) influx induced by the ELF-EMF exposure stimulated activity of the ERK, in turn, influences the expression of downstream proteins in this signaling pathway. Besides, ELF-EMF exposure also increased JNK1/2 phosphorylation through the activated ASK1, which plays a pivotal role in hippocampal neuronal cell death. However, oral administration of LSPCs (especially 60 and 90 mg kg(-1)) markedly improved expressions of p-CREB, p-ERK1/2 and p-JNK1/2, accompanied by decreased levels of glutamate, GABA, [Ca(2+)]i and NR2B. Thus, the results from the present study suggest that p-ERK1/2, p-JNK1/2, [Ca(2+)]i and p-CREB expression normalized, possibly via a NMDA receptor-channel through the changes of GABA, glutamate and NR2B, which might be responsible for the neuroprotective or memory enhancing effects of LSPCs.
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Effect of Intermittent Hypoxia on Neuro-functional Recovery Post Brain Ischemia in Mice.
J. Mol. Neurosci.
PUBLISHED: 07-17-2014
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Intermittent hypoxia was a simulation of a high-altitude environment. Neuro-inflammation post brain ischemia was considered as a vital impact which contributed to cognitive-functional deficit. The isoform of nitric oxide synthase (iNOS) was an inflammation factor secreted by microglias in neuro-inflammation. In this study, we established a high-altitude environment as the hypoxic condition. Twenty mice were selected and randomized into a hypoxia group (n?=?10) or a normoxia group (n?=?10) post three vessel occlusion-induced brain ischemia. An enhancement of cognitive-functional recovery was presented in the hypoxia group by survival neuron counting and revealed by the Morris water maze test. Meanwhile, a high level of hypoxia-inducable factor 1 (HIF-1) expression associated with a lower expression of iNOS was observed in the border between infarcts and normal tissue of the hippocampus in the hypoxia group. However, these phenomenons were blocked by HIF-1 inhibition. This suggested that the acceleration of cognitive-functional recovery induced by intermittent hypoxia may depend on HIF-1 activating. An imitation of the hypoxic condition with or without HIF-1 inhibition was operated on the BV-2 cell. A high level of HIF-1 expression associated with a lower-level expression of iNOS was performed in the hypoxic condition. These data suggested that intermittent hypoxia can accelerate cognitive function recovery through attenuating neuro-inflammation.
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Micromixing visualization and quantification in a microscale multi-inlet vortex nanoprecipitation reactor using confocal-based reactive micro laser-induced fluorescence.
Biomicrofluidics
PUBLISHED: 07-01-2014
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A technique for visualizing and quantifying reactive mixing for laminar and turbulent flow in a microscale chemical reactor using confocal-based microscopic laser induced fluorescence (confocal ?-LIF) was demonstrated in a microscale multi-inlet vortex nanoprecipitation reactor. Unlike passive scalar ?-LIF, the reactive ?-LIF technique is able to visualize and quantify micromixing effects. The confocal imaging results indicated that the flow in the reactor was laminar and steady for inlet Reynolds numbers of 10, 53, and 93. Mixing and reaction were incomplete at each of these Reynolds numbers. The results also suggested that although mixing by diffusion was enhanced near the midplane of the reactor at Rej?=?53 and 93 due to very thin bands of acidic and basic fluid forming as the fluid spiraled towards the center of the reactor, near the top, and bottom walls of the reactor, the lower velocities due to fluid friction with the walls hindered the formation of these thin bands, and, thus, resulted in large regions of unmixed and unreacted fluid. At Rej?=?240, the flow was turbulent and unsteady. The mixing and reaction processes were still found to be incomplete even at this highest Reynolds number. At the reactor midplane, the flow images at Rej?=?240 showed unmixed base fluid near the center of the reactor, suggesting that just as in the Rej?=?53 and 93 cases, lower velocities near the top and bottom walls of the reactor hinder the mixing and rection of the acidic and basic streams. Ensemble averages of line-scan profiles for the Rej?=?240 were then calculated to provide statistical quantification of the microscale mixing in the reactor. These results further demonstrate that even at this highest Reynolds number investigated, mixing and reaction are incomplete. Visualization and quantification of micromixing using this reactive ?-LIF technique can prove useful in the validation of computational fluid dynamics models of micromixing within microscale chemical reactors.
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[Clinical significance of the detection of serum neutrophil gelatinase-associated lipocalin in human colorectal cancer].
Zhonghua Wei Chang Wai Ke Za Zhi
PUBLISHED: 06-24-2014
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To explore the feasibility and clinical significance of the detection of serum neutrophil gelatinase-associated lipocalin(NGAL) in human colorectal cancer.
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A fluorescence method for detection of DNA and DNA methylation based on graphene oxide and restriction endonuclease HpaII.
Talanta
PUBLISHED: 06-22-2014
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DNA methylation plays an important role in many biological events and is associated with various diseases. Most traditional methods for detection of DNA methylation are based on the complex and expensive bisulfite method. In this paper, we report a novel fluorescence method to detect DNA and DNA methylation based on graphene oxide (GO) and restriction endonuclease HpaII. The skillfully designed probe DNA labeled with 5-carboxyfluorescein (FAM) and optimized GO concentration keep the probe/target DNA still adsorbed on the GO. After the cleavage action of HpaII the labeled FAM is released from the GO surface and its fluorescence recovers, which could be used to detect DNA in the linear range of 50 pM-50 nM with a detection limit of 43 pM. DNA methylation induced by transmethylase (Mtase) or other chemical reagents prevents HpaII from recognizing and cleaving the specific site; as a result, fluorescence cannot recover. The fluorescence recovery efficiency is closely related to the DNA methylation level, which can be used to detect DNA methylation by comparing it with the fluorescence in the presence of intact target DNA. The method for detection of DNA and DNA methylation is simple, reliable and accurate.
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The Aux/IAA gene rum1 involved in seminal and lateral root formation controls vascular patterning in maize (Zea mays L.) primary roots.
J. Exp. Bot.
PUBLISHED: 06-13-2014
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The maize (Zea mays L.) Aux/IAA protein RUM1 (ROOTLESS WITH UNDETECTABLE MERISTEMS 1) controls seminal and lateral root initiation. To identify RUM1-dependent gene expression patterns, RNA-Seq of the differentiation zone of primary roots of rum1 mutants and the wild type was performed in four biological replicates. In total, 2 801 high-confidence maize genes displayed differential gene expression with Fc ?2 and FDR ?1%. The auxin signalling-related genes rum1, like-auxin1 (lax1), lax2, (nam ataf cuc 1 nac1), the plethora genes plt1 (plethora 1), bbm1 (baby boom 1), and hscf1 (heat shock complementing factor 1) and the auxin response factors arf8 and arf37 were down-regulated in the mutant rum1. All of these genes except nac1 were auxin-inducible. The maize arf8 and arf37 genes are orthologues of Arabidopsis MP/ARF5 (MONOPTEROS/ARF5), which controls the differentiation of vascular cells. Histological analyses of mutant rum1 roots revealed defects in xylem organization and the differentiation of pith cells around the xylem. Moreover, histochemical staining of enlarged pith cells surrounding late metaxylem elements demonstrated that their thickened cell walls displayed excessive lignin deposition. In line with this phenotype, rum1-dependent mis-expression of several lignin biosynthesis genes was observed. In summary, RNA-Seq of RUM1-dependent gene expression in maize primary roots, in combination with histological and histochemical analyses, revealed the specific regulation of auxin signal transduction components by RUM1 and novel functions of RUM1 in vascular development.
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[Lactoferrin downregulates the expression of toll like receptor 4 stimulated by lipopolysaccharide in human periodontal ligament cells].
Hua Xi Kou Qiang Yi Xue Za Zhi
PUBLISHED: 06-03-2014
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To examine the role of lactoferrin (LF) on Toll like receptor 4 (TLR4) stimulated by lipopolysaccharide (LPS) in human periodontal ligament cells (hPDLCs).
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Autophagy is required for glucose homeostasis and lung tumor maintenance.
Cancer Discov
PUBLISHED: 05-29-2014
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Macroautophagy (autophagy hereafter) recycles intracellular components to sustain mitochondrial metabolism that promotes the growth, stress tolerance, and malignancy of lung cancers, suggesting that autophagy inhibition may have antitumor activity. To assess the functional significance of autophagy in both normal and tumor tissue, we conditionally deleted the essential autophagy gene, autophagy related 7 (Atg7), throughout adult mice. Here, we report that systemic ATG7 ablation caused susceptibility to infection and neurodegeneration that limited survival to 2 to 3 months. Moreover, upon fasting, autophagy-deficient mice suffered fatal hypoglycemia. Prior autophagy ablation did not alter the efficiency of non-small cell lung cancer (NSCLC) initiation by activation of oncogenic Kras(G12D) and deletion of the Trp53 tumor suppressor. Acute autophagy ablation in mice with preexisting NSCLC, however, blocked tumor growth, promoted tumor cell death, and generated more benign disease (oncocytomas). This antitumor activity occurred before destruction of normal tissues, suggesting that acute autophagy inhibition may be therapeutically beneficial in cancer.
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Response of a rice paddy soil methanogen to syntrophic growth as revealed by transcriptional analyses.
Appl. Environ. Microbiol.
PUBLISHED: 05-20-2014
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Members of Methanocellales are widespread in paddy field soils and play the key role in methane production. These methanogens feature largely in these organisms’ adaptation to low H2 and syntrophic growth with anaerobic fatty acid oxidizers. The adaptive mechanisms, however, remain unknown. In the present study, we determined the transcripts of 21 genes involved in the key steps of methanogenesis and acetate assimilation of Methanocella conradii HZ254, a strain recently isolated from paddy field soil. M. conradii was grown in monoculture and syntrophically with Pelotomaculum thermopropionicum (a propionate syntroph) or Syntrophothermus lipocalidus (a butyrate syntroph). Comparison of the relative transcript abundances showed that three hydrogenase-encoding genes and all methanogenesis-related genes tested were upregulated in cocultures relative to monoculture. The genes encoding formylmethanofuran dehydrogenase (Fwd), heterodisulfide reductase (Hdr), and the membrane-bound energy-converting hydrogenase (Ech) were the most upregulated among the evaluated genes. The expression of the formate dehydrogenase (Fdh)-encoding gene also was significantly upregulated. In contrast, an acetate assimilation gene was downregulated in cocultures. The genes coding for Fwd, Hdr, and the D subunit of F420-nonreducing hydrogenase (Mvh) form a large predicted transcription unit; therefore, the Mvh/Hdr/Fwd complex, capable of mediating the electron bifurcation and connecting the first and last steps of methanogenesis, was predicted to be formed in M. conradii. We propose that Methanocella methanogens cope with low H2 and syntrophic growth by (i) stabilizing the Mvh/Hdr/Fwd complex and (ii) activating formatedependent methanogenesis.
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A green route and rational design for ZnO-based high-efficiency photovoltaics.
Nanoscale
PUBLISHED: 04-11-2014
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In this work, at room-temperature and without any organic surfactants we reported two green and facile approaches for rapid synthesis of ZnO nanorods (NRs) and nanosheet-based ZnO hierarchical structures (NSHSs). Based on their structural advantages, the quasi-solid ZnO-DSCs achieved a record photoelectric conversion efficiency (PCE) of 6.83%.
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High-mobility group box 1 exacerbates CCl?-induced acute liver injury in mice.
Clin. Immunol.
PUBLISHED: 03-28-2014
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High-mobility group box 1 (HMGB1) is a nuclear factor that can also serve as an imflammatory mediator once released into extracellular milieu. Therefore, HMGB1 has been recognized to play a pivotal role in inflammatory diseases such as sepsis, acute lung injury, ischemia reperfusion injury and type 1 diabetes. Nevertheless, its impact on carbon tetrachloride (CCl4)-induced hepatic injury is yet to be elucidated. In the present report, we demonstrated evidence indicating that high levels of HMGB1 were not only present in the necrotic area of liver but also in the serum after CCl4 challenge. In line with these observations, administration of exogenous recombinant HMGB1 exacerbated CCl4-induced hepatic injury, while HMGB1 blocking antibody provided protection for mice against CCl4-induced acute liver injury as evidenced by the decrease of serum transaminase and reduction of hepatic tissues necrosis. Mechanistic studies revealed that blockade of HMGB1 attenuated CCl4-induced MDA accumulation along with improved SOD and GSH activity. Treatment of mice with HMGB1 neutralizing antibody also significantly inhibited the production of proinflammatory mediators TNF-? and IL-6 along with attenuated HMGB1 expression and its extracellular release. Together, our data suggest an essential role for HMGB1 in CCl4-induced acute liver injury, while HMGB1 neutralizing antibody could be served as an effective regimen for preventing CCl4-induced acute liver injury.
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Effects of virtual human animation on emotion contagion in simulated inter-personal experiences.
IEEE Trans Vis Comput Graph
PUBLISHED: 03-22-2014
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We empirically examined the impact of virtual human animation on the emotional responses of participants in a medical virtual reality system for education in the signs and symptoms of patient deterioration. Participants were presented with one of two virtual human conditions in a between-subjects experiment, static (non-animated) and dynamic (animated). Our objective measures included the use of psycho-physical Electro Dermal Activity (EDA) sensors, and subjective measures inspired by social psychology research included the Differential Emotions Survey (DES IV) and Positive and Negative Affect Survey (PANAS). We analyzed the quantitative and qualitative measures associated with participants’ emotional state at four distinct time-steps in the simulated interpersonal experience as the virtual patient’s medical condition deteriorated. Results suggest that participants in the dynamic condition with animations exhibited a higher sense of co-presence and greater emotional response as compared to participants in the static condition, corresponding to the deterioration in the medical condition of the virtual patient. Negative affect of participants in the dynamic condition increased at a higher rate than for participants in the static condition. The virtual human animations elicited a stronger response in negative emotions such as anguish, fear, and anger as the virtual patient’s medical condition worsened.
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Hierarchically oriented macroporous anode-supported solid oxide fuel cell with thin ceria electrolyte film.
ACS Appl Mater Interfaces
PUBLISHED: 03-21-2014
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Application of anode-supported solid oxide fuel cell (SOFC) with ceria based electrolyte has often been limited by high cost of electrolyte film fabrication and high electrode polarization. In this study, dense Gd0.1Ce0.9O2 (GDC) thin film electrolytes have been fabricated on hierarchically oriented macroporous NiO-GDC anodes by a combination of freeze-drying tape-casting of the NiO-GDC anode, drop-coating GDC slurry on NiO-GDC anode, and co-firing the electrolyte/anode bilayers. Using 3D X-ray microscopy and subsequent analysis, it has been determined that the NiO-GDC anode substrates have a porosity of around 42% and channel size from around 10 ?m at the electrolyte side to around 20 ?m at the other side of the NiO-GDC (away from the electrolyte), indicating a hierarchically oriented macroporous NiO-GDC microstructure. Such NiO-GDC microstructure shows a tortuosity factor of ?1.3 along the thickness direction, expecting to facilitate gas diffusion in the anode during fuel cell operation. SOFCs with such Ni-GDC anode, GDC film (30 ?m) electrolyte, and La0.6Sr0.4Co0.2Fe0.8O3-GDC (LSCF-GDC) cathode show significantly enhanced cell power output of 1.021 W cm(-2) at 600 °C using H2 as fuel and ambient air as oxidant. Electrochemical Impedance Spectroscopy (EIS) analysis indicates a decrease in both activation and concentration polarizations. This study has demonstrated that freeze-drying tape-casting is a very promising approach to fabricate hierarchically oriented porous substrate for SOFC and other applications.
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Effects of antiviral therapy on the cellular immune response in patients with chronic hepatitis B.
Mol Med Rep
PUBLISHED: 03-12-2014
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A weak T?cell immune response to the hepatitis B virus (HBV) is hypothesized to be the primary cause of chronic HBV infection. Emerging evidence suggests that long?term effective antiviral therapy restores the HBV?specific T?cell response from exhaustion. However, the extent to which the cellular immune response can be restored following the persistent suppression of HBV replication by antiviral therapy remains unclear. In order to investigate this question, 46 patients with chronic hepatitis B (CHB) treated with nucleos(t)ide analogues who demonstrated persistent suppression of HBV replication [defined as undetectable HBV DNA, hepatitis B e antigen (HBeAg) negative and adherence to antiviral therapy], 22 untreated CHB patients, 15 patients with acute hepatitis B (AHB) and 10 healthy adults were recruited. HBV?specific interferon?? enzyme?linked immunospot (IFN?? ELISPOT) assay and HBV?specific T?cell proliferation analysis were performed with a panel of overlapping peptides covering the envelope and core antigens. Data from this study showed that the HBV?specific immune responses to the peptide pools of the envelope and core protein in the treated patients were stronger than those in the untreated CHB patients, but significantly weaker than those in the AHB patients and healthy adults. A higher frequency of response to S than C peptide pools was confirmed by the IFN?? ELISPOT assay in the treated CHB patients. The restoration of antiviral immunity was clearly associated with a reduction in HBV DNA and the duration of HBV DNA suppression. In conclusion, the HBV?specific immune responses in the CHB patients can be significantly restored from exhaustion following the persistent suppression of HBV replication as a result of antiviral treatment with nucleos(t)ide analogues.
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Effect of Maillard reaction products on the physical and antimicrobial properties of edible films based on ?-polylysine and chitosan.
J. Sci. Food Agric.
PUBLISHED: 02-24-2014
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Edible films based on Maillard reaction products (MRPs) of ?-polylysine and chitosan, without the use of any plasticiser, were prepared by solution casting. The effect of Maillard reaction parameters (reaction time and the ratio of polylysine/chitosan) of ?-polylysine and chitosan on the structure, moisture content, water solubility, total colour difference and mechanical properties of edible films formed by MRPs were systematically evaluated.
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Structure and antimicrobial mechanism of ?-polylysine-chitosan conjugates through Maillard reaction.
Int. J. Biol. Macromol.
PUBLISHED: 02-09-2014
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The aim of the study was to testify the formation and antimicrobial activity of ?-polylysine-chitosan conjugate through Maillard reaction. The results of UV absorbance, browning index and fluorescence changes of Maillard reaction products (MRPs) between ?-polylysine and chitosan indicated there existed Maillard reaction between ?-polylysine and chitosan and the formation of their conjugate. The conjugate showed strong antibacterial activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and beer yeast. Morphologies of E. coli and S. aureus treated with the conjugate were observed by transmission electron microscopy (TEM). The results revealed that the conjugate of ?-polylysine and chitosan increased the permeability of the outer membrane (OM) and inner membrane (IM) and ultimately disrupted bacterial cell membranes, with the release of cellular cytoplasm.
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A novel copigment of quercetagetin for stabilization of grape skin anthocyanins.
Food Chem
PUBLISHED: 02-02-2014
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The thermal and light stability of grape skin anthocyanins combined with quercetagetin was investigated at designed pH values of 3, 4 and 5. The molar ratios of anthocyanins to quercetagetin were 1:10, 1:20 and 1:40 for thermally treatment at 70 °C, 80 °C and 90 °C, respectively, and the ratios were tested at 5:1, 1:1, 1:5 and 1:10 in the light exposure experiments. The degradation reaction of anthocyanins in the presence of quercetagetin followed the first-order kinetic model. The half-life (t?/?) of anthocyanins was extended significantly with the increase of quercetagetin concentration (p<0.05). The total colour difference values (?E(?)) for the anthocyanin solutions with quercetagetin were smaller than those without copigment under the same experimental conditions (pH and light exposure time). Compared with epigallocatechin gallate (EGCG), tea polyphenols (TP), myricitrin and rutin, quercetagetin was the most effective copigment to stabilize grape skin anthocyanins.
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Trajectory and risk factors for chemotherapy-induced nausea and vomiting in Asian patients with head and neck cancer.
Head Neck
PUBLISHED: 01-21-2014
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The purpose of this study was to analyze the trajectory of and risk factors for chemotherapy-induced nausea and vomiting in Asian patients with head and neck cancer.
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Pressure-volume curves: revisiting the impact of negative turgor during cell collapse by literature review and simulations of cell micromechanics.
New Phytol.
PUBLISHED: 01-21-2014
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The Scholander-Hammel pressure chamber has been used in thousands of papers to measure osmotic pressure, ?c , turgor pressure, Pt , and bulk modulus of elasticity, ?, of leaf cells by pressure-volume (PV) curve analysis. PV analysis has been questioned in the past. In this paper we use micromechanical analysis of leaf cells to examine the impact on PV curve analysis of negative turgor in living cells (Pt ). Models predict negative Pt (-0.1 to -1.8 MPa) depending on leaf cell size and shape in agreement with experimental values reported by J. J. Oertli. Modeled PV curves have linear regions even when Pt is quite negative, contrary to the arguments of M.T. Tyree. Negative Pt is totally missed by PV curve analysis and results in large errors in derived ?c and Pt but smaller errors in ?. A survey of leaf cell sizes vs habitat (arid, temperate, and rainforest), suggests that the majority of published PV curves result in errors of 0.1-1.8 MPa in derived ?c and Pt , whereby the error increases with decreasing cell size. We propose that small cell size in leaves is an ecological adaptation that permits plants to endure negative values of water potential with relatively little water loss.
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Mitochondrial apoptosis of lymphocyte is induced in type 2 diabetes.
Chin. Med. J.
PUBLISHED: 01-21-2014
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Lymphocyte function and homeostasis is associated with immune defence to infection. Apoptosis of lymphocytes might be a considerably important component which has an impact on immunity to infections in people with hyperglycemia. The aim of this study was to explore the mitochondrial apoptosis pathway of lymphocyte in diabetic patients.
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Composite catalyst of rosin carbon/Fe3O4: highly efficient counter electrode for dye-sensitized solar cells.
Chem. Commun. (Camb.)
PUBLISHED: 01-08-2014
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A composite catalyst of rosin carbon/Fe3O4 with marvellous morphology was synthesized and applied as a counter electrode (CE) in dye-sensitized solar cells (DSCs), demonstrating notable electrocatalytic activity for the reduction of I3(-). Based on this CE, a high power conversion efficiency of 8.11% was achieved, comparable to that of the traditional Pt CE.
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Influence of whey protein-beet pectin conjugate on the properties and digestibility of ?-carotene emulsion during in vitro digestion.
Food Chem
PUBLISHED: 01-07-2014
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The impact of a whey protein isolate (WPI)-beet pectin (BP) conjugate (formed by dry-heating) on the physical properties and digestibilities of ?-carotene and carrier oil in oil-in-water emulsions was studied when they passed through a model gastrointestinal system. ?-Carotene emulsions were stabilized by WPI, unconjugated and conjugated WPI-BP, separately. The emulsions were then passed through an in vitro digestion model and the mean droplet size, droplet distribution, zeta-potential, free fatty acids and ?-carotene released were measured. The stability to droplet flocculation and coalescence during digestion was increased for the WPI-BP conjugate stabilized emulsion. Addition of BP onto the WPI stabilized emulsions could inhibit the releases of carrier oil (MCT) and ?-carotene. The releases of free fatty acids and ?-carotene did not differ greatly between the unconjugated and conjugated WPI-BP stabilized emulsions. These results have important implications for protein-polysaccharide stabilized emulsions and conjugates used for the protection and delivery of bioactive compounds.
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Design, synthesis, and optoelectronic properties of dendrimeric Pt(II) complexes and their ability to inhibit intermolecular interaction.
Inorg Chem
PUBLISHED: 01-07-2014
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Dendrimeric Pt(II) complexes [(C(?)N)Pt(dpm)] and [Pt(C(?)N)2] (Hdpm = dipivaloylmethane, HC(?)N = 1,2-diphenylbenzoimidazole and its derivatives containing the carbazole dendrons) have been synthesized and characterized systematically. All of the complexes display green emission in the range of 495-535 nm that originated from the 360-440 nm absorption bands, which are assigned to d?(Pt)??*(L) metal-to-ligand charge transfer (MLCT) mixed with intraligand ?(L)??*(L) transition. Solution photoluminescence quantum yield (?p 0.26-0.31) of the heteroleptic complexes [(C(?)N)Pt(dpm)] obviously increases when compared with that of complex [(C(?)N)Pt(acac)]. Organic light-emitting diode devices based on these Pt(II) complexes with a multilayer configuration were fabricated and gave desirable electroluminescent (EL) performances, such as non- or less red-shifted EL spectra, in comparison with the photoluminescence spectra and slow efficiency roll-off with increasing brightness or current density. Complex [(t-BuCzCzPBI)Pt(dpm)] (where t-BuCzCzPBI = 1-(4-(3,6-di-(3,6-di-t-butyl-carbazol-9-yl))carbazol-9-yl)phenyl-2-phenylbenzoimidazole) showed the best performance, with a maximum current efficiency of 29.31 cd/A and a maximum external quantum efficiency (EQE) of 9.04% among the fabricated devices. Likewise, for homoleptic [Pt(t-BuCzCzPBI)2] dendrimer, the powder ?p (0.14) and maximum EQE (0.74%) improve by 7 and 7.4 times, respectively, as high as they do for nondendrimeric [Pt(1,2-diphenylbenzoimidazole)2] (0.02, 0.10%), although its efficiency is still lower than that of the heteroleptic counterpart due to the severely distorted square-planar geometry of the emitting core. These results reveal that large steric hindrance from ancillary ligand (dpm) or the homoleptic conformation can effectively inhibit intermolecular interaction for these dendrimeric Pt(II) complexes.
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Purification and identification of angiotensin I-converting enzyme-inhibitory peptides from apalbumin 2 during simulated gastrointestinal digestion.
J. Sci. Food Agric.
PUBLISHED: 01-05-2014
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Bee larvae are considered to be an important reservoir for proteins. However, little attention has been paid to the release of potential bioactive peptides from bee larva proteins. In this study the major protein in bee larvae was hydrolyzed in vitro by gastrointestinal enzymes. The peptide profile of the hydrolysis was characterized by gel filtration chromatography and tricine-SDS-PAGE. Furthermore, the bioactive peptide was isolated and identified by Q-TOF-MS/MS.
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Variational Implicit Solvation with Solute Molecular Mechanics: From Diffuse-Interface to Sharp-Interface Models.
SIAM J Appl Math
PUBLISHED: 09-24-2013
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Central in a variational implicit-solvent description of biomolecular solvation is an effective free-energy functional of the solute atomic positions and the solute-solvent interface (i.e., the dielectric boundary). The free-energy functional couples together the solute molecular mechanical interaction energy, the solute-solvent interfacial energy, the solute-solvent van der Waals interaction energy, and the electrostatic energy. In recent years, the sharp-interface version of the variational implicit-solvent model has been developed and used for numerical computations of molecular solvation. In this work, we propose a diffuse-interface version of the variational implicit-solvent model with solute molecular mechanics. We also analyze both the sharp-interface and diffuse-interface models. We prove the existence of free-energy minimizers and obtain their bounds. We also prove the convergence of the diffuse-interface model to the sharp-interface model in the sense of ?-convergence. We further discuss properties of sharp-interface free-energy minimizers, the boundary conditions and the coupling of the Poisson-Boltzmann equation in the diffuse-interface model, and the convergence of forces from diffuse-interface to sharp-interface descriptions. Our analysis relies on the previous works on the problem of minimizing surface areas and on our observations on the coupling between solute molecular mechanical interactions with the continuum solvent. Our studies justify rigorously the self consistency of the proposed diffuse-interface variational models of implicit solvation.
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Autophagy-mediated tumor promotion.
Cell
PUBLISHED: 09-16-2013
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Mouse models for cancer are revealing novel cancer-promoting roles for autophagy. Autophagy promotes tumor growth by suppressing the p53 response, maintaining mitochondrial function, sustaining metabolic homeostasis and survival in stress, and preventing diversion of tumor progression to benign oncocytomas.
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Antisense oligonucleotide suppression of human IGF-1R inhibits the growth and survival of in vitro cultured epithelial ovarian cancer cells.
J Ovarian Res
PUBLISHED: 08-26-2013
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Preclinical evaluation of the anti-neoplastic activity of antisense oligonucleotide (AS) suppression of human insulin-like growth factor I receptor (IGF-IR) in human epithelial ovarian cancer (EOC).
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Autophagy sustains mitochondrial glutamine metabolism and growth of BrafV600E-driven lung tumors.
Cancer Discov
PUBLISHED: 08-21-2013
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Autophagic elimination of defective mitochondria suppresses oxidative stress and preserves mitochondrial function. Here, the essential autophagy gene Atg7 was deleted in a mouse model of BrafV600E-induced lung cancer in the presence or absence of the tumor suppressor Trp53. Atg7 deletion initially induced oxidative stress and accelerated tumor cell proliferation in a manner indistinguishable from Nrf2 ablation. Compound deletion of Atg7 and Nrf2 had no additive effect, suggesting that both genes modulate tumorigenesis by regulating oxidative stress and revealing a potential mechanism of autophagy-mediated tumor suppression. At later stages of tumorigenesis, Atg7 deficiency resulted in an accumulation of defective mitochondria, proliferative defects, reduced tumor burden, conversion of adenomas and adenocarcinomas to oncocytomas, and increased mouse life span. Autophagy-defective tumor-derived cell lines were impaired in their ability to respire and survive starvation and were glutamine-dependent, suggesting that autophagy-supplied substrates from protein degradation sustains BrafV600E tumor growth and metabolism.
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Autophagy is required for mitochondrial function, lipid metabolism, growth and fate of KRAS (G12D) -driven lung tumors.
Autophagy
PUBLISHED: 08-15-2013
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Evidence suggests that the role of autophagy in tumorigenesis is context dependent. Using genetically engineered mouse models (GEMMs) for human non-small-cell lung cancer (NSCLC), we found that deletion of the essential autophagy gene, Atg7, in KRAS (G12D) -driven NSCLC inhibits tumor growth and converts adenomas and adenocarcinomas to benign oncocytomas characterized by the accumulation of respiration-defective mitochondria. Atg7 is required to preserve mitochondrial fatty acid oxidation (FAO) to maintain lipid homeostasis upon additional loss of Trp53 in NSCLC. Furthermore, cell lines derived from autophagy-deficient tumors depend on glutamine to survive starvation. This suggests that autophagy is essential for the metabolism, growth and fate of NSCLC.
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Phase-field approach to implicit solvation of biomolecules with Coulomb-field approximation.
J Chem Phys
PUBLISHED: 07-19-2013
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A phase-field variational implicit-solvent approach is developed for the solvation of charged molecules. The starting point of such an approach is the representation of a solute-solvent interface by a phase field that takes one value in the solute region and another in the solvent region, with a smooth transition from one to the other on a small transition layer. The minimization of an effective free-energy functional of all possible phase fields determines the equilibrium conformations and free energies of an underlying molecular system. All the surface energy, the solute-solvent van der Waals interaction, and the electrostatic interaction are coupled together self-consistently through a phase field. The surface energy results from the minimization of a double-well potential and the gradient of a field. The electrostatic interaction is described by the Coulomb-field approximation. Accurate and efficient methods are designed and implemented to numerically relax an underlying charged molecular system. Applications to single ions, a two-plate system, and a two-domain protein reveal that the new theory and methods can capture capillary evaporation in hydrophobic confinement and corresponding multiple equilibrium states as found in molecular dynamics simulations. Comparisons of the phase-field and the original sharp-interface variational approaches are discussed.
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Autophagy suppresses progression of K-ras-induced lung tumors to oncocytomas and maintains lipid homeostasis.
Genes Dev.
PUBLISHED: 07-05-2013
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Macroautophagy (autophagy hereafter) degrades and recycles proteins and organelles to support metabolism and survival in starvation. Oncogenic Ras up-regulates autophagy, and Ras-transformed cell lines require autophagy for mitochondrial function, stress survival, and engrafted tumor growth. Here, the essential autophagy gene autophagy-related-7 (atg7) was deleted concurrently with K-ras(G12D) activation in mouse models for non-small-cell lung cancer (NSCLC). atg7-deficient tumors accumulated dysfunctional mitochondria and prematurely induced p53 and proliferative arrest, which reduced tumor burden that was partly relieved by p53 deletion. atg7 loss altered tumor fate from adenomas and carcinomas to oncocytomas-rare, predominantly benign tumors characterized by the accumulation of defective mitochondria. Surprisingly, lipid accumulation occurred in atg7-deficient tumors only when p53 was deleted. atg7- and p53-deficient tumor-derived cell lines (TDCLs) had compromised starvation survival and formed lipidic cysts instead of tumors, suggesting defective utilization of lipid stores. atg7 deficiency reduced fatty acid oxidation (FAO) and increased sensitivity to FAO inhibition, indicating that with p53 loss, Ras-driven tumors require autophagy for mitochondrial function and lipid catabolism. Thus, autophagy is required for carcinoma fate, and autophagy defects may be a molecular basis for the occurrence of oncocytomas. Moreover, cancers require autophagy for distinct roles in metabolism that are oncogene- and tumor suppressor gene-specific.
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Engineering Clostridia Neurotoxins with elevated catalytic activity.
Toxicon
PUBLISHED: 07-04-2013
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BoNT/B and TeNT cleave substrate VAMP2 at the same scissile bond, yet these two toxins showed different efficiency on substrate hydrolysis and had different requirements for the recognition of P2 site of VAMP2, E(78). These differences may be due to their different composition of their substrate recognition pockets in the active site. Swapping of LC/T S1 pocket residue, L(230), with the corresponding isoleucine in LC/B increased LC/T activity by ?25 fold, while swapping of LC/B S1 pocket residue, S(201), with the corresponding proline in LC/T increased LC/B activity by ?10 fold. Optimization of both S1 and S1 pocket residues of LC/T, LC/T (K(168)E, L(230)I) elevated LC/T activity by more than 100-fold. The highly active LC/T derivative engineered in this study has the potential to be used as a more effective tool to study mechanisms of exocytosis in central neuron. The LC/B derivative with elevated activity has the potential to be developed into novel therapy to minimize the impact of immunoresistance during BoNT/B therapy.
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Detection of DNA damage based on metal-mediated molecular beacon and DNA strands displacement reaction.
Spectrochim Acta A Mol Biomol Spectrosc
PUBLISHED: 06-26-2013
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DNA hairpin structure probes are usually designed by forming intra-molecular duplex based on Watson-Crick hydrogen bonds. In this paper, a molecular beacon based on silver ions-mediated cytosine-Ag(+)-cytosine base pairs was used to detect DNA. The inherent characteristic of the metal ligation facilitated the design of functional probe and the adjustment of its binding strength compared to traditional DNA hairpin structure probes, which make it be used to detect DNA in a simple, rapid and easy way with the help of DNA strands displacement reaction. The method was sensitive and also possesses the good specificity to differentiate the single base mismatched DNA from the complementary DNA. It was also successfully applied to study the damage effect of classic genotoxicity chemicals such as styrene oxide and sodium arsenite on DNA, which was significant in food science, environmental science and pharmaceutical science.
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Synthesis for the mesomer and racemate of thiophene-based double helicene under irradiation.
J. Org. Chem.
PUBLISHED: 06-10-2013
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In this work, the racemate and mesomer of the thiophene-based naphthalene-cored double helicenes (1) were obtained efficiently by one-pot photocyclization of 1,1,2,2-tetrakis(dithieno[2,3-b:3,2-d]thiophen-2-yl)ethene in the presence of iodine in dry benzene. The structure of meso-1a was confirmed by single crystal X-ray analysis. The chiral resolution of the racemate was carried out by chiral HPLC, and the chiral properties, such as CD spectra, optical rotations, and half-life of enantiomers were characterized.
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[Analysis of null alleles for 17 Y chromosome-short tandem repeat loci in infertile males].
Zhonghua Yi Xue Yi Chuan Xue Za Zhi
PUBLISHED: 06-08-2013
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To investigate the characteristics of null allele for 17 Y-chromosomal short tandem repeats (Y-STR) loci in a group of infertile males.
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Periodic migration in a physical model of cells on micropatterns.
Phys. Rev. Lett.
PUBLISHED: 06-06-2013
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We extend a model for the morphology and dynamics of a crawling eukaryotic cell to describe cells on micropatterned substrates. This model couples cell morphology, adhesion, and cytoskeletal flow in response to active stresses induced by actin and myosin. We propose that protrusive stresses are only generated where the cell adheres, leading to the cells effective confinement to the pattern. Consistent with experimental results, simulated cells exhibit a broad range of behaviors, including steady motion, turning, bipedal motion, and periodic migration, in which the cell crawls persistently in one direction before reversing periodically. We show that periodic motion emerges naturally from the coupling of cell polarization to cell shape by reducing the model to a simplified one-dimensional form that can be understood analytically.
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Synthesis and structure of bulls horn-shaped oligothienoacene with seven fused thiophene rings.
J. Org. Chem.
PUBLISHED: 06-03-2013
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A novel bulls horn-shaped oligothienoacene with seven fused thiophene rings (1) based on dithieno[2,3-b:2,3-d]thiophene (2) was efficiently synthesized. X-ray diffraction data indicate that 1 possesses an extraordinary compressed sandwich-herringbone arrangement and shows strong intermolecular S···C and S···S interactions. In addition, the UV/vis properties, theoretical calculations, and cyclic voltammetry behaviors of 1 are also described.
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Influence of autoantibodies against AT1 receptor and AGTR1 polymorphisms on candesartan-based antihypertensive regimen: Results from the Study of Optimal Treatment in Hypertensive Patients with Anti-AT1-Receptor Autoantibodies trial.
J Am Soc Hypertens
PUBLISHED: 05-28-2013
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The autoantibodies against angiotensin AT1 receptors (AT1-AAs) in patients with essential hypertension exhibited an agonistic action like angiotensin II and maintained high blood pressure (BP). Angiotensin II receptor gene (AGTR1) polymorphisms were associated with BP response to RAS inhibition in the hypertensive population. Furthermore, the BP response to AT1 receptor blockers varied significantly among individuals with hypertension. We hypothesized that the polymorphisms of the AGTR1 and AT1-AAs might affect antihypertensive response to AT1 receptor blockers based in patients with primary hypertension. Patients who received a candesartan-based regimen came from the SOT-AT1 study (Study of Optimal Treatment in Hypertensive Patients with Anti-AT1-Receptor Autoantibodies). The established enzyme-labeled immunosorbent assay was used to detect AT1-AAs in the sera of the patients. Genotype 3 single nucleotide polymorphisms in AGTR1 gene was used by DNA sequencing. The correlations among AT1-AAs, AGTR1 gene polymorphisms or haplotypes, and the antihypertensive effect candesartan-based were analyzed using SPSS. The percentage of systolic BP reduction that was candesartan-based was greater in AT1-AA positive groups than in AT1-AA negative ones (21 ± 8 vs. 18 ± 9; P = .001). Meanwhile, systolic BP reduction that was candesartan-based was more significant in the group of rs5186 AC genotypes than AA homozygotes after adjusting for other confounding factors (37.55 ± 13.7 vs. 32.47 ± 17.27 mm Hg; adjusted P = .028). Furthermore, haplotypes (GCC) and (AAC) had impacts on the antihypertensive effect of candesartan therapy. The AT1-AAs, AGTR1 gene polymorphisms and haplotypes solely or jointly have influences on candesartan-based antihypertensive response in patients with primary hypertension.
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Efficacy and safety of sirolimus-eluting stents versus bare-metal stents in coronary artery disease patients with diabetes: a meta-analysis.
Cardiovasc J Afr
PUBLISHED: 05-22-2013
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To compare by meta-analysis the efficacy and safety of sirolimus-eluting and bare-metal stents in coronary artery disease (CAD) patients with diabetes.
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Covalent complexation and functional evaluation of (-)-epigallocatechin gallate and ?-lactalbumin.
Food Chem
PUBLISHED: 04-02-2013
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The covalent complexation between (-)-epigallocatechin gallate (EGCG) and ?-lactalbumin (?-La), and the effect of EGCG on the antioxidative activity and emulsifying properties of ?-La were investigated. The turbidity of a solution of 1% ?-La and 0.2% EGCG decreased after 24h reaction at pH 8.0 and 60°C, less than the value of ?-La alone. The interaction between ?-La and EGCG at pH 8.0 was more pronounced than that at pH 6.0 or 7.0, as evidenced by the reduced amplitude of amide A, and I, and II bands of ?-La by FT-IR and the increase in the total phenolic content and denaturation temperature. These results implied that EGCG was covalently linked to ?-La at pH 8.0. In addition, compared with the control of ?-La, ?-La-EGCG complexes had significantly increased antioxidative activity. The emulsions stabilized by ?-La-EGCG complexes, compared with that by ?-La alone, had much smaller droplet sizes, which indicated the emulsifying property of ?-La was improved.
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PPAR? agonist fenofibrate attenuates TNF-?-induced CD40 expression in 3T3-L1 adipocytes via the SIRT1-dependent signaling pathway.
Exp. Cell Res.
PUBLISHED: 03-14-2013
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The ligand-activated transcription factor peroxisome proliferator-activated receptor-? (PPAR?) participates in the regulation of cellular inflammation. More recent studies indicated that sirtuin1 (SIRT1), a NAD(+)-dependent deacetylase, regulates the inflammatory response in adipocytes. However, whether the role of PPAR? in inflammation is mediated by SIRT1 remains unclear. In this study, we aimed to determine the effect of PPAR? agonist fenofibrate on the expressions of SIRT1 and pro-inflammatory cytokine CD40 and underlying mechanisms in 3T3-L1 adipocytes. We found that fenofibrate inhibited CD40 expression and up-regulated SIRT1 expression in tumor necrosis factor-? (TNF-?)-stimulated adipocytes, and these effects of fenofibrate were reversed by PPAR? antagonist GW6471. Moreover, SIRT1 inhibitors sirtinol/nicotinamide (NAM) or knockdown of SIRT1 could attenuate the effect of fenofibrate on TNF-?-induced CD40 expression in adipocytes. Importantly, NF-?B inhibitor pyrrolidine dithiocarbamate (PDTC) augmented the effect of fenofibrate on CD40 expression in adipocytes. Further study found that fenofibrate decreased the expression of acetylated-NF-?B p65 (Ac-NF-?B p65) in TNF-?-stimulated adipocytes, and the effect of fenofibrate was abolished by SIRT1 inhibition. In addition, fenofibrate up-regulated SIRT1 expression through AMPK in TNF-?-stimulated adipocytes. Taken together, these findings indicate that PPAR? agonist fenofibrate inhibits TNF-?-induced CD40 expression in 3T3-L1 adipocytes via the SIRT1-dependent signaling pathway.
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SIRT1 inhibits TNF-?-induced apoptosis of vascular adventitial fibroblasts partly through the deacetylation of FoxO1.
Apoptosis
PUBLISHED: 03-13-2013
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Sirtuin 1 (SIRT1), a NAD(+)-dependent class III histone deacetylase, participates in regulating cellular apoptosis, senescence and metabolism by deacetylating histones and multiple transcription factors. In this study, we aimed to determine the effect of SIRT1 on the apoptosis of vascular adventitial fibroblasts (VAFs) and related signaling pathways. SIRT1 was found in the nucleus of VAFs and translocated into the cytoplasm in response to tumor necrosis factor-? (TNF-?). Moreover, SIRT1 protein expression was reduced in VAFs stimulated with TNF-?. In addition, TNF-? increased the apoptosis of VAFs. Activation of SIRT1 by resveratrol (RSV) or overexpression of SIRT1 attenuated TNF-?-induced VAF apoptosis by decreasing the percentage of apoptotic cells and cleaved caspase-3 protein expression and increasing the Bcl-2/Bax ratio. In contrast, inhibition of SIRT1 by sirtinol/nicotinamide or knockdown of SIRT1 enhanced apoptosis of VAFs. On the other hand, knockdown of FoxO1 reduced TNF-?-induced VAF apoptosis. SIRT1 interacted with FoxO1 in VAFs by the co-immunoprecipitation assay. Further study showed that RSV or SIRT1 overexpression decreased acetylated-FoxO1 (Ac-FoxO1) protein expression in VAFs stimulated with TNF-?. Knockdown of SIRT1 resulted in an increase in Ac-FoxO1 protein expression. Taken together, these findings indicate that SIRT1 inhibits the apoptosis of VAFs, whereas FoxO1 promotes VAF apoptosis. Furthermore, the inhibitory effect of SIRT1 on VAF apoptosis is partly mediated by the deacetylation of FoxO1.
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Separation of chlorogenic acid and concentration of trace caffeic acid from natural products by pH-zone-refining countercurrent chromatography.
J Sep Sci
PUBLISHED: 03-06-2013
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Chlorogenic acid and caffeic acid were selected as test samples for separation by the pH-zone-refining countercurrent chromatography (CCC). The separation of these test samples was performed with a two-phase solvent system composed of methyl-tert-butyl-ether/acetonitrile/water at a volume ratio of 4:1:5 v/v/v where trifluoroacetic acid (TFA; 8 mM) was added to the organic stationary phase as a retainer and NH4 OH (10 mM) to the aqueous mobile phase as an eluter. Chlorogenic acid was successfully separated from Flaveria bidentis (L.) Kuntze (F. bidentis) and Lonicerae Flos by pH-zone-refining CCC, a slightly polar two-phase solvent system composed of methyl-tert-butyl-ether/acetonitrile/n-butanol/water at a volume ratio of 4:1:1:5 v/v/v/v was selected where TFA (3 mM) was added to the organic stationary phase as a retainer and NH4 OH (3 mM) to the aqueous mobile phase as an eluter. A 16.2 mg amount of chlorogenic acid with the purity of 92% from 1.4 g of F. bidentis, and 134 mg of chlorogenic acid at the purity of 99% from 1.3 g of crude extract of Lonicerae Flos have been obtained. These results suggest that pH-zone-refining CCC is suitable for the isolation of the chlorogenic acid from the crude extracts of F. bidentis and Lonicerae Flos.
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One-step cloning of intron-containing hairpin RNA constructs for RNA interference via isothermal in vitro recombination system.
Planta
PUBLISHED: 02-25-2013
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Hairpin RNA-based RNA interference (hpRNAi) has become a powerful tool for exploring gene function in reverse genetics. Although, several methods are available for making constructs that express hpRNAi, multiple time-consuming cloning steps are usually involved. Here, we introduce an efficient and flexible hpRNAi vector construction method via the isothermal in vitro recombination system (IR-hpRNAi). For an IR-hpRNAi reaction, two PCR products of a target gene sequence are generated, which containS complementary ends (~20 bp) to each other and to the ends of linearized vector, are fused in a way of head-to-head or tail-to-tail into the vector. This IR-hpRNAi method offers two options to construct the RNAi vectors. Using this method, we created a IR-hpRNAi construct for the Arabidopsis PDS3 gene,and verified the silencing effect via Agrobacterium-mediated transformation. The IR-hpRNAi system rules out the requirement of engineering restriction enzyme cutting sites in target DNA fragments, and is ligation-independent. Thus, this method has advantages over the other hpRNAi construction methods.
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A new type of low-cost counter electrode catalyst based on platinum nanoparticles loaded onto silicon carbide (Pt/SiC) for dye-sensitized solar cells.
Phys Chem Chem Phys
PUBLISHED: 02-20-2013
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A Pt/SiC nanocomposite with ~10 wt% Pt loading was used as a counter electrode (CE) in dye-sensitized solar cells (DSCs), it shows a high power conversion efficiency (PCE) of 7.07% (a DSC with a SiC CE has a PCE of 3.29%), reaching 98.5% of the level obtained using a Pt CE (7.18%). This work provides substantial support for developing low-cost Pt-loaded composite CEs for DSCs. Pt/SiC use is expected to reduce the dependence on the Pt in DSCs, while it can also be expected to be used in many chemical and electrochemical processes required to control the amount of Pt and prevent Pt nanoparticle aggregation.
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Influence of pH, metal chelator, free radical scavenger and interfacial characteristics on the oxidative stability of ?-carotene in conjugated whey protein-pectin stabilised emulsion.
Food Chem
PUBLISHED: 02-11-2013
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The influence of whey protein isolate (WPI)-beet pectin conjugates formed by dry-heating on the oxidative stability of ?-carotene in O/W emulsions was studied. It was mainly focused on the influence of pH, metal chelator, free radical scavenger and interfacial characteristics on the degradation of ?-carotene in the emulsion stabilised by conjugate. The conjugate increased the oxidative stability of ?-carotene in the emulsion as compared to their unconjugated mixture at pH 7.0. The desferoxamine retarded ?-carotene degradation at pH 4.0 more effectively than pH 7.0 and more effectively in the emulsion with the conjugate than the unconjugated mixture (p<0.05). The addition of 200 mg/kg ?-tocopherol significantly improved the stability of ?-carotene in the conjugate stabilised emulsion. The emulsions were washed to remove conjugate not absorbed to the emulsion droplet interface, indicating that unabsorbed emulsifiers could protect ?-carotene. It suggested that WPI-pectin conjugate could be used to protect bioactive lipids in emulsions.
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How does hypoxia inducible factor-1? participate in enhancing the glycolysis activity in cervical cancer?
Ann Diagn Pathol
PUBLISHED: 02-01-2013
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The objective of this study is to explore the role of hypoxia inducible factor-1 (HIF-1) in glycolysis activity and its relationship with malignant biologic behaviors of cervical cancer. Immunohistochemistry was performed to study the protein expression and distribution of HIF-1? and glucose transport protein 1 (GLUT1) in cervical tissue of 158 cases, including 28 with normal cervical epithelium, 32 with cervical intraepithelial neoplasia, and 98 with invasive cervical cancer. Cobalt(II) chloride was used to induce hypoxia in Hela and Siha cells; the biologic behaviors of cells cultured in normal or hypoxic environments were monitored by colorimetric, Transwell, flow cytometry, and enzyme-linked immunosorbent assay; immunocytochemistry, Western blot, and reverse transcription-polymerase chain reaction were used to observe gene and protein expression of HIF-1?, GLUT1, and hexokinase II in cell lines during normoxia and hypoxia. The expression of HIF-1? and GLUT1 gradually increased from normal cervical tissue to cervical intraepithelial neoplasia, then to cervical cancer. There were significant differences among these groups (P < .05). HIF-1? was strongly associated with pathologic differentiation, clinic stage, magnitude of lesions, and patient age, whereas GLUT1 was associated with lymphatic metastasis (P < .05). HIF-1? was strongly associated with expression of GLUT1 (P < .05). In hypoxia, proliferation, invasion, resistance to apoptosis, and glycolysis of both Hela and Siha were enhanced compared with cells in normoxia (P < .05). Both gene and protein expressions of GLUT1 and hexokinase II were strengthened, whereas only the protein expression of HIF-1? was stronger in hypoxia than that in normoxia (P < .05). The results of Hela in normoxia and in hypoxia were similar to those of Siha (P > .05). HIF-1? plays a key role in cervical cancer both in vivo and in vitro. The role of HIF-1? can be implemented mainly by up-regulating its downstream gene, such as GLUT1, and the main mechanism may enhance glycolytic ability. Strong up-regulation and the role of HIF-1? suggest that HIF-1? could be an important factor in the onset and progression of cervical cancer and could be an attractive therapeutic molecular target for that type of cancer.
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Online isolation and purification of four phthalide compounds from Chuanxiong rhizoma using high-speed counter-current chromatography coupled with semi-preparative liquid chromatography.
J Chromatogr A
PUBLISHED: 01-26-2013
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The phthalide compounds of Chuanxiong rhizoma including senkyunolide A, levistolide A, Z-ligustilide and 3-butylidenephthalide, have been reported as the biologically active compounds because of their therapeutic effects. In this work, online high-speed counter-current chromatography coupled with semi-preparative liquid chromatography instrument was set up, and online separation of the four compounds has been simultaneously achieved using this instrument. In this study, using all the selected solvent system, Z-ligustilide and 3-butylidenephthalide were eluted in one peak by high-speed counter-current chromatography. Using high-speed counter-current chromatography with a solvent system of n-hexane-ethyl acetate-methanol-water-acetonitrile (8:2:5:5:5, v/v), 3.6 mg of senkyunolide A (94.4%) and 3.0mg of levistolide A (95.3%) were obtained from 100mg of the crude extract. Coeluted Z-ligustilide and 3-butylidenephthalide peak fraction (8 mL) from high-speed counter-current chromatography was directly transferred and injected to the semi-preparative liquid chromatography for further separation. Finally, 5.6 mg of Z-ligustilide (97.5%) and 4.8 mg of 3-butylidenephthalide (99.3%) were obtained. The identification of these four compounds was performed by quadrupole time-of-flight mass spectrometer, (1)H and (13)C nuclear magnetic resonance spectrometer.
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The genetics of Henoch-Schönlein purpura: a systematic review and meta-analysis.
Rheumatol. Int.
PUBLISHED: 01-17-2013
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Henoch-Schönlein purpura (HSP) is the most common form of systemic vasculitis of unknown etiology. This study aimed at reviewing published studies investigating the association of genetic polymorphisms with HSP and its severity. We systematically reviewed all published data on genetic risk factors for HSP by searching MEDLINE. We also performed a meta-analysis of association studies of HLA-DRB1-01, 07, and 11, angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) polymorphism. We identified 45 studies investigating polymorphisms in 39 genes in association with HSP and/or its severity. Most of these genes are involved in immunological and/or inflammatory responses or vasomotor regulation. Most results were negative. The most convincing finding is the association of HLA-DRB1 01, 07, and 11 with HSP susceptibility. The overall odds ratios (ORs) for the three loci were significant for HSP: HLA-DRB1 01 (OR = 1.805, 95 % CI 1.259-2.588, p = 0.0012); HLA-DRB1 07 (OR = 0.671, 95 % CI 0.469-0.961, p = 0.058); HLA-DRB1 11 (OR = 2.001, 95 % CI 1.50-2.67, p = 0.027). Genetic regulation of endothelial function, such as polymorphisms in genes coding rennin-angiotensin system (RAS) components, endothelial nitric oxide synthases, Inter-Cellular Adhesion Molecule 1, and vascular endothelial growth factor, could also confer effect on HSP. In addition, MEFV, whose mutations cause familial Mediterranean fever, could be an important candidate gene for HSP. Further large studies are required to investigate the association between genetic polymorphisms and HSP. Alternative approaches, such as genome-wide association study, are necessary to help to identify genetic risks for HSP.
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Development of a Real-Time Fluorescence Loop-Mediated Isothermal Amplification Assay for Rapid and Quantitative Detection of Fusarium oxysporum f. sp. cubense Tropical Race 4 In Soil.
PLoS ONE
PUBLISHED: 01-01-2013
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Fusarium oxysporum f. sp. cubense (Foc), the causal agent of Fusarium wilt (Panama disease), is one of the most devastating diseases of banana (Musa spp.). The Foc tropical race 4 (TR4) is currently known as a major concern in global banana production. No effective resistance is known in Musa to Foc, and no effective measures for controlling Foc once banana plants have been infected in place. Early and accurate detection of Foc TR4 is essential to protect banana industry and guide banana planting. A real-time fluorescence loop-mediated isothermal amplification assay (RealAmp) was developed for the rapid and quantitative detection of Foc TR4 in soil. The detection limit of the RealAmp assay was approximately 0.4 pg/µl plasmid DNA when mixed with extracted soil DNA or 10(3) spores/g of artificial infested soil, and no cross-reaction with other relative pathogens were observed. The RealAmp assay for quantifying genomic DNA of TR4 was confirmed by testing both artificially and naturally infested samples. Quantification of the soil-borne pathogen DNA of Foc TR4 in naturally infested samples was no significant difference compared to classic real-time PCR (P>0.05). Additionally, RealAmp assay was visual with an improved closed-tube visual detection system by adding SYBR Green I fluorescent dye to the inside of the lid prior to amplification, which avoided the inhibitory effects of the stain on DNA amplification and makes the assay more convenient in the field and could thus become a simple, rapid and effective technique that has potential as an alternative tool for the detection and monitoring of Foc TR4 in field, which would be a routine DNA-based testing service for the soil-borne pathogen in South China.
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The Maize (Zea mays L.) AUXIN/INDOLE-3-ACETIC ACID Gene Family: Phylogeny, Synteny, and Unique Root-Type and Tissue-Specific Expression Patterns during Development.
PLoS ONE
PUBLISHED: 01-01-2013
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The plant hormone auxin plays a key role in the coordination of many aspects of growth and development. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) genes encode instable primary auxin responsive regulators of plant development that display a protein structure with four characteristic domains. In the present study, a comprehensive analysis of the 34 members of the maize Aux/IAA gene family was performed. Phylogenetic reconstructions revealed two classes of Aux/IAA proteins that can be distinguished by alterations in their domain III. Seven pairs of paralogous maize Aux/IAA proteins were discovered. Comprehensive root-type and tissue-specific expression profiling revealed unique expression patterns of the diverse members of the gene family. Remarkably, five of seven pairs of paralogous genes displayed highly correlated expression patterns in roots. All but one (ZmIAA23) tested maize Aux/IAA genes were auxin inducible, displaying two types of auxin induction within three hours of treatment. Moreover, 51 of 55 (93%) differential Aux/IAA expression patterns between different root-types followed the expression tendency: crown roots > seminal roots > primary roots > lateral roots. This pattern might imply root-type-specific regulation of Aux/IAA transcript abundance. In summary, the detailed analysis of the maize Aux/IAA gene family provides novel insights in the evolution and developmental regulation and thus the function of these genes in different root-types and tissues.
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Suppression of mitochondrial complex I influences cell metastatic properties.
PLoS ONE
PUBLISHED: 01-01-2013
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Despite the fact that mitochondrial dysfunction has an important role in tumorigenesis and metastasis, the underlying mechanism remains to be elucidated. Mitochondrial Complex I (NADH:ubiquinone oxidoreductase) is the first and the largest protein complex of the mitochondrial electron-transport chain (ETC),which has an essential role in maintaining mitochondrial function and integrity. In this study, we separately knocked down two subunits of mitochondrial complex I, GRIM-19 or NDUFS3, and investigated their effects on metastatic behaviors and explored the possible mechanisms. Our data showed that stable down-modulation of GRIM-19 or NDUFS3 decreased complex I activity and reactive oxygen species (ROS) production; led to enhanced cell adhesion, migration, invasion, and spheroid formation; and influenced the expressions of extracellular matrix (ECM) molecules and its related proteins. We also observed that the expressions of GRIM-19, NDUFS3, and ECM elements were correlated with invasive capabilities of breast cancer cell lines. These results suggest that inhibition of complex I affects metastatic properties of cancer cells, and mitochondrial ROS might play a crucial role in these processes by regulating ECM.
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Comparison of the two major classes of assembly algorithms: overlap-layout-consensus and de-bruijn-graph.
Brief Funct Genomics
PUBLISHED: 12-19-2011
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Since the completion of the cucumber and panda genome projects using Illumina sequencing in 2009, the global scientific community has had to pay much more attention to this new cost-effective approach to generate the draft sequence of large genomes. To allow new users to more easily understand the assembly algorithms and the optimum software packages for their projects, we make a detailed comparison of the two major classes of assembly algorithms: overlap-layout-consensus and de-bruijn-graph, from how they match the Lander-Waterman model, to the required sequencing depth and reads length. We also discuss the computational efficiency of each class of algorithm, the influence of repeats and heterozygosity and points of note in the subsequent scaffold linkage and gap closure steps. We hope this review can help further promote the application of second-generation de novo sequencing, as well as aid the future development of assembly algorithms.
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Evaluation of applied biosystems MicroSeq real-time PCR system for detection of Listeria monocytogenes in food. Performance Tested Method 011002.
J AOAC Int
PUBLISHED: 12-15-2011
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Increasingly, more food companies are relying on molecular methods, such as PCR, for pathogen detection due to their improved simplicity, sensitivity, and rapid time to results. This report describes the validation of a new Real-Time PCR method to detect Listeria monocytogenes in nine different food matrixes. The complete system consists of the MicroSEQ L. monocytogenes Detection Kit, sample preparation, the Applied Biosystems 7500 Fast Real-Time PCR instrument, and RapidFinder Express software. Two sample preparation methods were validated: the PrepSEQ Nucleic Acid extraction kit and the PrepSEQ Rapid Spin sample preparation kit. The test method was compared to the ISO 11290-1 reference method using an unpaired-study design to detect L. monocytogenes in roast beef, cured bacon, lox (smoked salmon), lettuce, whole cows milk, dry infant formula, ice cream, salad dressing, and mayonnaise. The MicroSEQ L. monocytogenes Detection Kit and the ISO 11290-1 reference method showed equivalent detection based on Chi-square analysis for all food matrixes when the samples were prepared using either of the two sample preparation methods. An independent validation confirmed these findings on smoked salmon and whole cows milk. The MicroSEQ kit detected all 50 L. monocytogenes strains tested, and none of the 30 nontargeted bacteria strains.
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Determination of polymer additives-antioxidants and ultraviolet (UV) absorbers by high-performance liquid chromatography coupled with UV photodiode array detection in food simulants.
J. Agric. Food Chem.
PUBLISHED: 12-05-2011
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An analytical method for the quantitative determination of migration levels of polymer additives such as antioxidants and UV absorbers in food packages by high-performance liquid chromatography coupled with UV-vis photodiode array detection has been developed. The pretreatment step involved solid-phase extraction with silica C18 cartridges. The analytical method showed good linearity, presenting regression coefficients (R(2)) ? 0.9990 for all compounds. This optimized method was also validated with respect to precision, reproducibility, stability, and accuracy. The limits of detection and quantification were between 0.09 and 1.72 ?g mL(-1) and between 0.20 and 5.64 ?g mL(-1) for 12 analytes, respectively. Recoveries were in the range of 67.48 and 108.55%, with relative standard deviations between 2.76 and 9.81%. Migration levels of antioxidants and UV absorbers were determined. Butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol (BHT), 2,4-di-tert-butylphenol, Cyanox 2246, Irganox 1035, Tinuvin 326, Tinuvin 328, Irganox 1010, and Irganox 1330 were detected; BHT and Cyanox 2246 were at higher levels than the specific migration levels in some food simulants.
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Neutral cuprous complexes as ratiometric oxygen gas sensors.
Dalton Trans
PUBLISHED: 12-02-2011
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Four neutral mononuclear Cu(I) complexes, [Cu(pyin)(PPh(3))(2)] (1a), [Cu(pyin)(DPEphos)] (1b), [Cu(quin)(PPh(3))(2)] (2a) and [Cu(quin)(DPEphos)] (2b) (Hpyin = 2-(2-pyridyl)indole, Hquin = 2-(2-quinolyl)indole and DPEphos = bis(2-(diphenylphosphino)phenyl)ether) have been synthesized. X-Ray crystal structure analysis revealed that the central Cu(I) ion in all complexes is in a distorted tetrahedral coordination environment. All four complexes display the typical metal-to-ligand charge transfer (MLCT) absorption band at 371, 363, 413 and 402 nm, respectively. No emission was observed from any complexes in the solid state due to triplet-triplet annihilation. However, the complexes show unusual dual-emission originating from intraligand charge-transfer (ILCT) and MLCT transitions, when dispersed in a rigid matrix (e.g. PMMA) or in frozen CH(2)Cl(2). The oxidation potential of Cu(I)/Cu(II) in these neutral complexes, ?0.5 V (vs. Ag/AgCl), is lower than those of cationic Cu(I) complexes. Films containing 10 wt% of these complexes in PMMA shows ratiometric fluorescent oxygen gas sensing property with a response ratio of 0.3-3.2 and response time of 3-4 s. Complex 2b acts as a ratiometric oxygen gas sensor with good reversibility through energy and electron transfer mechanisms under the loss of a counteranion.
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Focal pontine lesions provide evidence that intrinsic functional connectivity reflects polysynaptic anatomical pathways.
J. Neurosci.
PUBLISHED: 10-22-2011
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Intrinsic functional connectivity detected by functional MRI (fMRI) provides a useful but indirect approach to study the organization of human brain systems. An unresolved question is whether functional connectivity measured by resting-state fMRI reflects anatomical connections. In this study, we used the well-characterized anatomy of cerebrocerebellar circuits to directly test whether intrinsic functional connectivity is associated with an anatomic pathway. Eleven first-episode stroke patients were scanned five times during a period of 6 months, and 11 healthy control subjects were scanned three times within 1 month. In patients with right pontine strokes, the functional connectivity between the right motor cortex and the left cerebellum was selectively reduced. This connectivity pattern was reversed in patients with left pontine strokes. Although factors beyond anatomical connectivity contribute to fMRI measures of functional correlation, these results provide direct evidence that functional connectivity depends on intact connections within a specific polysynaptic pathway.
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Factors controlling plasticity of leaf morphology in Robinia pseudoacacia: III. biophysical constraints on leaf expansion under long-term water stress.
Physiol Plant
PUBLISHED: 09-21-2011
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In this article, we measured the relative growth rate (RGR) of leaves of Robinia pseudoacacia seedlings under well-watered and water-stressed conditions (mid-day ?(w) = leaf water potential estimated with a pressure bomb of -0.48 and -0.98 MPa, respectively). Pressure-volume (PV) curves were done on growing leaves at 25, 50 and 95% of the mature size (growth stage) in order to compute solute potential (?) and turgor pressure (?(P) ) as a function of ?(w) . The PV curves and diurnal measurements of ?(w) and RGR allowed us to evaluate the parameters (cell wall extensibility m and growth turgor threshold Y) of the Lockhart equation, RGR = m(?(P)-Y), at each growth stage. Our data showed that m and Y did change with leaf age, but the changes were slow enough to evaluate m and Y on any given day. We believe this is the first study to provide evidence that the Lockhart equation adequately quantifies leaf growth of trees over a range of time domains. The value of m linearly declined and Y linearly increased with growth stage. Also, mild drought stress caused a decline in m and increase in Y relative to controls. Although water stress caused an osmotic adjustment which, in turn, increased ?(P) in stressed plants relative to controls, the RGR and final leaf sizes were reduced in water-stressed plants because of the impact of water stress on decreased m and increased Y.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.