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Sample records for human h4 neuroglioma

  1. Pogostemon cablin as ROS Scavenger in Oxidant-Induced Cell Death of Human Neuroglioma Cells

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    Hyung Woo Kim

    2010-01-01

    Full Text Available Reactive oxygen species (ROS have been implicated in the pathogenesis of a wide range of acute and long-term neurodegenerative diseases. This study was undertaken to examine the efficacy of Pogostemon cablin, a well-known herb in Korean traditional medicine, on ROS-induced brain cell injury. Pogostemon cablin effectively protected human neuroglioma cell line A172 against both the necrotic and apoptotic cell death induced by hydrogen peroxide (H2O2. The effect of Pogostemon cablin was dose dependent at concentrations ranging from 0.2 to 5 mg ml−1. Pogostemon cablin significantly prevented depletion of cellular ATP and activation of poly ADP-ribose polymerase induced by H2O2. The preservation of functional integrity of mitochondria upon the treatment of Pogostemon cablin was also confirmed by 3-(4,5-dimethyl-2-thiazyl-2,5-diphenyl-2-H-tetrazolium bromide assay. Furthermore, Pogostemon cablin significantly prevented H2O2-induced release of cytochrome c into cytosol. Determination of intracellular ROS showed that Pogostemon cablin might exert its role as a powerful scavenger of intracellular ROS. The present study suggests the beneficial effect of Pogostemon cablin on ROS-induced neuroglial cell injury. The action of Pogostemon cablin as a ROS-scavenger might underlie the mechanism.

  2. Quercetin nanoparticles induced autophagy and apoptosis through AKT/ERK/Caspase-3 signaling pathway in human neuroglioma cells: In vitro and in vivo.

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    Lou, Miao; Zhang, Li-Na; Ji, Pei-Gang; Feng, Fu-Qiang; Liu, Jing-Hui; Yang, Chen; Li, Bao-Fu; Wang, Liang

    2016-12-01

    Neuroglioma is a complex neuroglial tumor involving dysregulation of many biological pathways at multiple levels. Quercetin is a potent cancer therapeutic agent presented in fruit and vegetables, preventing tumor proliferation, and is a well known cancer therapeutic agent and autophagy mediator. Recent studies showed that drug delivery by nanoparticles have enhanced efficacy with reduced side effects. In this regard, gold-quercetin into poly (dl-lactide-co-glycolide) nanoparticles was examined. In the present study, quercetin nanoparticle induced cell autophagy and apoptosis in human neuroglioma cell was investigated. Quercetin nanoparticle administrated to animals displayed suppressed role in tumor growth. The cell viability was deterined through CCK8 assay. Transmission electron microscopy was utilized to observe the formation of autophagosome. The cell apoptosis was assessed by annexin V-PI staining. The protein expression of cell autophagy regulators and tumor suppressors were analyzed via western blot and RT-PCR. Treatment of human neuroglioma cell with quercetin nanoparticle induced cell death in a dose-and time-dependent manner. The flow cytometry results showed that the proportion of the apoptosis cells had gained after quercetin nanoparticle treatment compared to untreatment group. Moreover, the expression of activated PI3K/AKT and Bcl-2 were down-regulated upon quercetin nanoparticle treatment in human neuroglioma cells. The expression level of LC3 and ERK as well as cytoplasm p53, cleaved Caspase-3 and PARP was positively correlated with the concentration of quercetin nanoparticle. In addition, p-mTOR and GAIP were obviously down-regulated by quercetin nanoparticle treatment in a dose-dependent manner. These results indicated that quercetin nanoparticle could induce autophagy and apoptosis in human neuroglioma cells, the underlying molecular mechanisms, at least partly, through activation LC3/ERK/Caspase-3 and suppression AKT/mTOR signaling.

  3. Turnover of C99 is Controlled by a Crosstalk between ERAD and Ubiquitin-Independent Lysosomal Degradation in Human Neuroglioma Cells

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    Bustamante, Hianara A.; Rivera-Dictter, Andrés; Cavieres, Viviana A.; Muñoz, Vanessa C.; González, Alexis; Lin, Yimo; Mardones, Gonzalo A.; Burgos, Patricia V.

    2013-01-01

    Alzheimer’s disease (AD) is characterized by the buildup of amyloid-β peptides (Aβ) aggregates derived from proteolytic processing of the β-amyloid precursor protein (APP). Amyloidogenic cleavage of APP by β-secretase/BACE1 generates the C-terminal fragment C99/CTFβ that can be subsequently cleaved by γ-secretase to produce Aβ. Growing evidence indicates that high levels of C99/CTFβ are determinant for AD. Although it has been postulated that γ-secretase-independent pathways must control C99/CTFβ levels, the contribution of organelles with degradative functions, such as the endoplasmic reticulum (ER) or lysosomes, is unclear. In this report, we investigated the turnover and amyloidogenic processing of C99/CTFβ in human H4 neuroglioma cells, and found that C99/CTFβ is localized at the Golgi apparatus in contrast to APP, which is mostly found in endosomes. Conditions that localized C99/CTFβ to the ER resulted in its degradation in a proteasome-dependent manner that first required polyubiquitination, consistent with an active role of the ER associated degradation (ERAD) in this process. Furthermore, when proteasomal activity was inhibited C99/CTFβ was degraded in a chloroquine (CQ)-sensitive compartment, implicating lysosomes as alternative sites for its degradation. Our results highlight a crosstalk between degradation pathways within the ER and lysosomes to avoid protein accumulation and toxicity. PMID:24376644

  4. Intra- and inter-nucleosomal interactions of the histone H4 tail revealed with a human nucleosome core particle with genetically-incorporated H4 tetra-acetylation.

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    Wakamori, Masatoshi; Fujii, Yoshifumi; Suka, Noriyuki; Shirouzu, Mikako; Sakamoto, Kensaku; Umehara, Takashi; Yokoyama, Shigeyuki

    2015-11-26

    Post-translational modifications (PTMs) of histones, such as lysine acetylation of the N-terminal tails, play crucial roles in controlling gene expression. Due to the difficulty in reconstituting site-specifically acetylated nucleosomes with crystallization quality, structural analyses of histone acetylation are currently performed using synthesized tail peptides. Through engineering of the genetic code, translation termination, and cell-free protein synthesis, we reconstituted human H4-mono- to tetra-acetylated nucleosome core particles (NCPs), and solved the crystal structures of the H4-K5/K8/K12/K16-tetra-acetylated NCP and unmodified NCP at 2.4 Å and 2.2 Å resolutions, respectively. The structure of the H4-tetra-acetylated NCP resembled that of the unmodified NCP, and the DNA wrapped the histone octamer as precisely as in the unmodified NCP. However, the B-factors were significantly increased for the peripheral DNAs near the N-terminal tail of the intra- or inter-nucleosomal H4. In contrast, the B-factors were negligibly affected by the H4 tetra-acetylation in histone core residues, including those composing the acidic patch, and at H4-R23, which interacts with the acidic patch of the neighboring NCP. The present study revealed that the H4 tetra-acetylation impairs NCP self-association by changing the interactions of the H4 tail with DNA, and is the first demonstration of crystallization quality NCPs reconstituted with genuine PTMs.

  5. Characterization of novel non-clonal intrachromosomal rearrangements between the H4 and PTEN genes (H4/PTEN) in human thyroid cell lines and papillary thyroid cancer specimens

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    Puxeddu, Efisio [Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States); Zhao Guisheng [Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States); Stringer, James R. [Department of Molecular Genetics, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States); Medvedovic, Mario [Center for Biostatistic Service, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States); Moretti, Sonia [Dipartimento di Medicina Interna, Universita degli Studi di Perugia, Via E. dal Pozzo, Perugia 06126, (Italy); Fagin, James A. [Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, PO Box 670547, Cincinnati, OH 45267-0547 (United States)]. E-mail: james.fagin@uc.edu

    2005-02-15

    The two main forms of RET rearrangement in papillary thyroid carcinomas (PTC) arise from intrachromosomal inversions fusing the tyrosine kinase domain of RET with either the H4 (RET/PTC1) or the ELE1/RFG genes (RET/PTC3). PTEN codes for a dual-specificity phosphatase and maps to chromosome 10q22-23. Germline mutations confer susceptibility to Cowden syndrome whereas somatic mutations or deletions are common in several sporadic human tumors. Decreased PTEN expression has been implicated in thyroid cancer development. We report the characterization of a new chromosome 10 rearrangement involving H4 and PTEN. The initial H4/PTEN rearrangement was discovered as a non-specific product of RT-PCR for RET/PTC1 in irradiated thyroid cell lines. Sequencing revealed a transcript consisting of exon 1 and 2 of H4 fused with exons 3-6 of PTEN. Nested RT-PCR with specific primers bracketing the breakpoints confirmed the H4/PTEN rearrangements in irradiated KAT-1 and KAT-50 cells. Additional H4/PTEN variants, generated by recombination of either exon 1 or exon 2 of H4 with exon 6 of PTEN, were found in non-irradiated KAK-1, KAT-50, ARO and NPA cells. Their origin through chromosomal recombination was confirmed by detection of the reciprocal PTEN/H4 product. H4/PTEN recombination was not a clonal event in any of the cell lines, as Southern blots with appropriate probes failed to demonstrate aberrant bands, and multicolor FISH of KAK1 cells with BAC probes for H4 and PTEN did not show a signal overlap in all cells. Based on PCR of serially diluted samples, the minimal frequency of spontaneous recombination between these loci was estimated to be approximately 1/10{sup 6} cells. H4/PTEN products were found by nested RT-PCR in 4/14 normal thyroid tissues (28%) and 14/18 PTC (78%) (P < 0.01). H4/PTEN is another example of recombination involving the H4 locus, and points to the high susceptibility of thyroid cells to intrachromosomal gene rearrangements. As this also represents a

  6. Pancreatic Transdifferentiation and Glucose-Regulated Production of Human Insulin in the H4IIE Rat Liver Cell Line

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    Binhai Ren

    2016-04-01

    Full Text Available Due to the limitations of current treatment regimes, gene therapy is a promising strategy being explored to correct blood glucose concentrations in diabetic patients. In the current study, we used a retroviral vector to deliver either the human insulin gene alone, the rat NeuroD1 gene alone, or the human insulin gene and rat NeuroD1 genes together, to the rat liver cell line, H4IIE, to determine if storage of insulin and pancreatic transdifferentiation occurred. Stable clones were selected and expanded into cell lines: H4IIEins (insulin gene alone, H4IIE/ND (NeuroD1 gene alone, and H4IIEins/ND (insulin and NeuroD1 genes. The H4IIEins cells did not store insulin; however, H4IIE/ND and H4IIEins/ND cells stored 65.5 ± 5.6 and 1475.4 ± 171.8 pmol/insulin/5 × 106 cells, respectively. Additionally, several β cell transcription factors and pancreatic hormones were expressed in both H4IIE/ND and H4IIEins/ND cells. Electron microscopy revealed insulin storage vesicles in the H4IIE/ND and H4IIEins/ND cell lines. Regulated secretion of insulin to glucose (0–20 mmol/L was seen in the H4IIEins/ND cell line. The H4IIEins/ND cells were transplanted into diabetic immunoincompetent mice, resulting in normalization of blood glucose. This data shows that the expression of NeuroD1 and insulin in liver cells may be a useful strategy for inducing islet neogenesis and reversing diabetes.

  7. Histone H4 lysine 20 acetylation is associated with gene repression in human cells

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    Kaimori, Jun-Ya; Maehara, Kazumitsu; Hayashi-Takanaka, Yoko; Harada, Akihito; Fukuda, Masafumi; Yamamoto, Satoko; Ichimaru, Naotsugu; Umehara, Takashi; Yokoyama, Shigeyuki; Matsuda, Ryo; Ikura, Tsuyoshi; Nagao, Koji; Obuse, Chikashi; Nozaki, Naohito; Takahara, Shiro; Takao, Toshifumi; Ohkawa, Yasuyuki; Kimura, Hiroshi; Isaka, Yoshitaka

    2016-01-01

    Histone acetylation is generally associated with gene activation and chromatin decondensation. Recent mass spectrometry analysis has revealed that histone H4 lysine 20, a major methylation site, can also be acetylated. To understand the function of H4 lysine 20 acetylation (H4K20ac), we have developed a specific monoclonal antibody and performed ChIP-seq analysis using HeLa-S3 cells. H4K20ac was enriched around the transcription start sites (TSSs) of minimally expressed genes and in the gene body of expressed genes, in contrast to most histone acetylation being enriched around the TSSs of expressed genes. The distribution of H4K20ac showed little correlation with known histone modifications, including histone H3 methylations. A motif search in H4K20ac-enriched sequences, together with transcription factor binding profiles based on ENCODE ChIP-seq data, revealed that most transcription activators are excluded from H4K20ac-enriched genes and a transcription repressor NRSF/REST co-localized with H4K20ac. These results suggest that H4K20ac is a unique acetylation mark associated with gene repression. PMID:27064113

  8. Recombinant human B7-H4 expressed in Escherichia coli inhibits T lymphocyte proliferation and IL-2 secretion in vitro

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    Yi-xiang MAO; Xue-guang ZHANG; Yong-Jing CHEN; Van GE; Hong-bing MA; Jian-feng YU; Hong-ya WU; Yu-min HU; Qin WANG; Qin SHI

    2006-01-01

    Aim: To explore the biofunctions of human B7-H4 generated from prokaryotic system. Methods: The gene of human B7-H4 extracellular region (IgⅤ-like and IgC-like domains) was obtained by PCR from human cDNA FLJ22418 and then inserted into the prokaryotic expression vector pGEX-5X-3 expressing glutathione. r-transferase (GST) fusion protein. After being identified by restriction enzyme digestion and sequencing, the recombinant vector was transferred into host strain E coli BL21-RIL(DE3). A 47 kDa fusion protein (GST/hB7-H4) was induced by isopropyl-beta-D-thiogalactopyranoside (IPTG) and purified by standard methods reported in the prokaryotic system. The inhibitory effect of GST/hB7-H4 on proliferation of T cells was observed in vitro by CD3mAb activated T-cell cultur-ing system and [3H]-thymidine incorporation assay. The concentrations of interleukin-2 and iterferon-g in the supernatants of T cells were determined by ELISA. Results: We successfully constructed the method for high-level expression and purification of the hB7-H4 extracellular domain as GST fusion protein from E coli. The GST/hB7-H4 fusion protein produced in bacteria had obvious biological activity to inhibit T-lymphocyte proliferation and IL-2 secretion. Conclusion: The prokaryote expression system could be used to generate hB7-H4 protein with natural spatial conformations and biological functions, which provided an efficient and economical way for the preparation of this target protein.

  9. Mass spectrometry identifies and quantifies 74 unique histone H4 isoforms in differentiating human embryonic stem cells.

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    Phanstiel, Doug; Brumbaugh, Justin; Berggren, W Travis; Conard, Kevin; Feng, Xuezhu; Levenstein, Mark E; McAlister, Graeme C; Thomson, James A; Coon, Joshua J

    2008-03-18

    Epigenetic regulation through chromatin is thought to play a critical role in the establishment and maintenance of pluripotency. Traditionally, antibody-based technologies were used to probe for specific posttranslational modifications (PTMs) present on histone tails, but these methods do not generally reveal the presence of multiple modifications on a single-histone tail (combinatorial codes). Here, we describe technology for the discovery and quantification of histone combinatorial codes that is based on chromatography and mass spectrometry. We applied this methodology to decipher 74 discrete combinatorial codes on the tail of histone H4 from human embryonic stem (ES) cells. Finally, we quantified the abundances of these codes as human ES cells undergo differentiation to reveal striking changes in methylation and acetylation patterns. For example, H4R3 methylation was observed only in the presence of H4K20 dimethylation; such context-specific patterning exemplifies the power of this technique.

  10. H4 histamine receptors mediate cell cycle arrest in growth factor-induced murine and human hematopoietic progenitor cells.

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    Anne-France Petit-Bertron

    Full Text Available The most recently characterized H4 histamine receptor (H4R is expressed preferentially in the bone marrow, raising the question of its role during hematopoiesis. Here we show that both murine and human progenitor cell populations express this receptor subtype on transcriptional and protein levels and respond to its agonists by reduced growth factor-induced cell cycle progression that leads to decreased myeloid, erythroid and lymphoid colony formation. H4R activation prevents the induction of cell cycle genes through a cAMP/PKA-dependent pathway that is not associated with apoptosis. It is mediated specifically through H4R signaling since gene silencing or treatment with selective antagonists restores normal cell cycle progression. The arrest of growth factor-induced G1/S transition protects murine and human progenitor cells from the toxicity of the cell cycle-dependent anticancer drug Ara-C in vitro and reduces aplasia in a murine model of chemotherapy. This first evidence for functional H4R expression in hematopoietic progenitors opens new therapeutic perspectives for alleviating hematotoxic side effects of antineoplastic drugs.

  11. ChIP on SNP-chip for genome-wide analysis of human histone H4 hyperacetylation

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    Porter Christopher J

    2007-09-01

    Full Text Available Abstract Background SNP microarrays are designed to genotype Single Nucleotide Polymorphisms (SNPs. These microarrays report hybridization of DNA fragments and therefore can be used for the purpose of detecting genomic fragments. Results Here, we demonstrate that a SNP microarray can be effectively used in this way to perform chromatin immunoprecipitation (ChIP on chip as an alternative to tiling microarrays. We illustrate this novel application by mapping whole genome histone H4 hyperacetylation in human myoblasts and myotubes. We detect clusters of hyperacetylated histone H4, often spanning across up to 300 kilobases of genomic sequence. Using complementary genome-wide analyses of gene expression by DNA microarray we demonstrate that these clusters of hyperacetylated histone H4 tend to be associated with expressed genes. Conclusion The use of a SNP array for a ChIP-on-chip application (ChIP on SNP-chip will be of great value to laboratories whose interest is the determination of general rules regarding the relationship of specific chromatin modifications to transcriptional status throughout the genome and to examine the asymmetric modification of chromatin at heterozygous loci.

  12. TNF-α inhibits aquaporin 5 expression in human salivary gland acinar cells via suppression of histone H4 acetylation.

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    Yamamura, Yoshiko; Motegi, Katsumi; Kani, Kouichi; Takano, Hideyuki; Momota, Yukihiro; Aota, Keiko; Yamanoi, Tomoko; Azuma, Masayuki

    2012-08-01

    Sjögren's syndrome is a systemic autoimmune disease characterized by reductions in salivary and lacrimal secretions. The mechanisms underlying these reductions remain unclear. We have previously shown that TNF-α plays an important role in the destruction of acinar structures. Here we examined TNF-α's function in the expression of aquaporin (AQP) 5 in human salivary gland acinar cells. Immortalized human salivary gland acinar (NS-SV-AC) cells were treated with TNF-α, and then the expression levels of AQP5 mRNA and protein were analysed. In addition, the mechanisms underlying the reduction of AQP5 expression by TNF-α treatment were investigated. TNF-α-treatment of NS-SV-AC cells significantly suppressed the expression levels of AQP5 mRNA and protein, and reduced the net fluid secretion rate. We examined the expression and activation levels of DNA methyltransferases (Dnmts) in NS-SV-AC cells treated with TNF-α. However, no significant changes were observed in the expression or activation levels of Dnmt1, Dnmt3a or Dnmt3b. Although we also investigated the role of NF-κB activity in the TNF-α-induced suppression of AQP5 expression in NS-SV-AC cells, we detected similar TNF-α suppression of AQP5 expression in non-transfected cells and in a super-repressor form of IκBα cDNA-transfected cell clones. However, interestingly, chromatin immunoprecipitation analysis demonstrated a remarkable decrease in levels of acetylated histone H4 associated with the AQP5 gene promoter after treatment with TNF-α in NS-SV-AC cells. Therefore, our results may indicate that TNF-α inhibition of AQP5 expression in human salivary gland acinar cells is due to the epigenetic mechanism by suppression of acetylation of histone H4.

  13. The extracellular loop 2 (ECL2 of the human histamine H4 receptor substantially contributes to ligand binding and constitutive activity.

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    David Wifling

    Full Text Available In contrast to the corresponding mouse and rat orthologs, the human histamine H4 receptor (hH4R shows extraordinarily high constitutive activity. In the extracellular loop (ECL, replacement of F169 by V as in the mouse H4R significantly reduced constitutive activity. Stabilization of the inactive state was even more pronounced for a double mutant, in which, in addition to F169V, S179 in the ligand binding site was replaced by M. To study the role of the FF motif in ECL2, we generated the hH4R-F168A mutant. The receptor was co-expressed in Sf9 insect cells with the G-protein subunits Gαi2 and Gβ1γ2, and the membranes were studied in [3H]histamine binding and functional [35S]GTPγS assays. The potency of various ligands at the hH4R-F168A mutant decreased compared to the wild-type hH4R, for example by 30- and more than 100-fold in case of the H4R agonist UR-PI376 and histamine, respectively. The high constitutive activity of the hH4R was completely lost in the hH4R-F168A mutant, as reflected by neutral antagonism of thioperamide, a full inverse agonist at the wild-type hH4R. By analogy, JNJ7777120 was a partial inverse agonist at the hH4R, but a partial agonist at the hH4R-F168A mutant, again demonstrating the decrease in constitutive activity due to F168A mutation. Thus, F168 was proven to play a key role not only in ligand binding and potency, but also in the high constitutive activity of the hH4R.

  14. The extracellular loop 2 (ECL2) of the human histamine H4 receptor substantially contributes to ligand binding and constitutive activity.

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    Wifling, David; Bernhardt, Günther; Dove, Stefan; Buschauer, Armin

    2015-01-01

    In contrast to the corresponding mouse and rat orthologs, the human histamine H4 receptor (hH4R) shows extraordinarily high constitutive activity. In the extracellular loop (ECL), replacement of F169 by V as in the mouse H4R significantly reduced constitutive activity. Stabilization of the inactive state was even more pronounced for a double mutant, in which, in addition to F169V, S179 in the ligand binding site was replaced by M. To study the role of the FF motif in ECL2, we generated the hH4R-F168A mutant. The receptor was co-expressed in Sf9 insect cells with the G-protein subunits Gαi2 and Gβ1γ2, and the membranes were studied in [3H]histamine binding and functional [35S]GTPγS assays. The potency of various ligands at the hH4R-F168A mutant decreased compared to the wild-type hH4R, for example by 30- and more than 100-fold in case of the H4R agonist UR-PI376 and histamine, respectively. The high constitutive activity of the hH4R was completely lost in the hH4R-F168A mutant, as reflected by neutral antagonism of thioperamide, a full inverse agonist at the wild-type hH4R. By analogy, JNJ7777120 was a partial inverse agonist at the hH4R, but a partial agonist at the hH4R-F168A mutant, again demonstrating the decrease in constitutive activity due to F168A mutation. Thus, F168 was proven to play a key role not only in ligand binding and potency, but also in the high constitutive activity of the hH4R.

  15. Quantitative analysis of modified proteins and their positional isomers by tandem mass spectrometry: human histone H4.

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    Pesavento, James J; Mizzen, Craig A; Kelleher, Neil L

    2006-07-01

    Here we show that fragment ion abundances from dissociation of ions created from mixtures of multiply modified histone H4 (11 kDa) or of N-terminal synthetic peptides (2 kDa) correspond to their respective intact ion abundances measured by Fourier transform mass spectrometry. Isomeric mixtures of modified forms of the same protein are resolved and quantitated with a precision of easing many of the systematic biases that more strongly affect small peptides (e.g., differences in ionization efficiency and ion m/z values). The ion fragmentation methods validated here are directly extensible to intact human proteins to derive quantitative information on the highly related and often isomeric protein forms created by combinatorial arrays of posttranslational modifications.

  16. ChIP on SNP-chip for genome-wide analysis of human histone H4 hyperacetylation

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    Porter Christopher J; Palidwor Gareth; Palmer Claire; Muro Enrique M; McCann Jennifer A; Andrade-Navarro Miguel A; Rudnicki Michael A

    2007-01-01

    Abstract Background SNP microarrays are designed to genotype Single Nucleotide Polymorphisms (SNPs). These microarrays report hybridization of DNA fragments and therefore can be used for the purpose of detecting genomic fragments. Results Here, we demonstrate that a SNP microarray can be effectively used in this way to perform chromatin immunoprecipitation (ChIP) on chip as an alternative to tiling microarrays. We illustrate this novel application by mapping whole genome histone H4 hyperacety...

  17. [Expression and Subcellular Distribution of Costimulatory Molecules B7-H1,B7-H3 and B7-H4 in Human Hematologic Malignancy Cell Lines].

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    Zhang, Wei; Wang, Jing; Wang, Yan-Fang; Zhu, Ming-Xia; Wan, Wen-Li; Li, Hai-Shen; Wu, Fei-Fei; Yan, Xin-Xing; Ke, Xiao-Yan

    2016-10-01

    To investigate the expression and subcellular distribution of costimulatory molecules B7-H1, B7-H3 and B7-H4 in human hematologic malignancy cell lines. The expression and subcellular distribution of B7-H1, B7-H3 and B7-H4 in 13 human hematologic malignancy cell lines were determined by RT-PCR, qPCR, Western blot and flow cytometry, the peripheral blood mononuclear cells (PB MNC) of 12 volunteers were used as control. The mRNA of B7-H1, B7-H3 and B7-H4 was widely expressed in PB MNC and hematologic malignancy cell lines, with a lower level of B7-H4. The mRNA expression of 3 molecules was highest in Maver, Z138, and HL-60, respectively, while among them the B7-H3 and B7-H4 had no expression in CZ1. The nuclear and cytoplasmic protein of 3 costimulatory molecules abnormally overexpressed only in hematologic malignancy cell lines, with the highest level in U937, Z138, and Raji, respectively, while the B7-H3 and B7-H4 had no expression in CZ1. There were differences among mRNA expression, nuclear and cytoplasmic protein expression of 3 molecules in cell lines derived from the same type of tumor, but the differences of expression in mRNA and protein levels were not exactly the same. The B7-H3 expression abundance in membrane localization was higher in U937, Maver and Z138, while the membrane protein of B7-H1 and B7-H4 had no or low expression in 13 cell lines. The mRNA expression of costimulatory molecules B7-H1, B7-H3 and B7-H4 can be widely detected. The protein level of 3 costimulatory molecules abnormally overexpressed only in hematologic malignancy cell lines, moreover the subcellular localizations mostly was found in nucleus and cytoplasm, while the membrane protein expresses in low level or had no expression. There are differences among the expression of 3 molecules in cell lines derived from the same type of tumor.

  18. Effects of currently used pesticides in the AhR-CALUX assay: comparison between the human TV101L and the rat H4IIE cell line

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    Long, Manhai; Laier, Peter; Vinggaard, Anne Marie

    2003-01-01

    to be a rapid and sensitive assay for assessing the potency of AhR-activating compounds. We have used the AhR-CALUX assay to investigate the AhR-mediated activity of the persistent organochlorine insecticide dieldrin and twenty-two pesticides currently used in Denmark by employing the rat H4IIE and the human TV......101L hepatoma cell lines. In comparison the results indicated that the rat H4IIE cell line is more sensitive than the human TV101L for detection of TCDD inducing AhR-CALUX activity. The pesticides iprodione, chlorpyrifos and prochloraz showed dose-dependent AhR agonistic effects in both cell lines...... at concentrations above 10, 1 and 1 microM, respectively. However, some pesticides (methiocarb, chlorothalonil, tribenuron-methyl, paclobutrazol and tolchlofos-methyl) elicited differential responses in the two cell lines....

  19. Effects of currently used pesticides in the AhR-CALUX assay: comparison between the human TV101L and the rat H4IIE cell line

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    Long, M.; Laier, Peter; Vinggaard, Anne;

    2003-01-01

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates many of the biologic and toxicological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. The in vitro chemically activated luciferase expression (CALUX) assay has been proven...... TV101L hepatoma cell lines. In comparison the results indicated that the rat H4IIE cell line is more sensitive than the human TV101L for detection of TCDD inducing AhR-CALUX activity. The pesticides iprodione, chlorpyrifos and prochloraz showed dose-dependent AhR agonistic effects in both cell lines...

  20. Differences in TCDD-elicited gene expression profiles in human HepG2, mouse Hepa1c1c7 and rat H4IIE hepatoma cells

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    Burgoon Lyle D

    2011-04-01

    Full Text Available Abstract Background 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD is an environmental contaminant that elicits a broad spectrum of toxic effects in a species-specific manner. Current risk assessment practices routinely extrapolate results from in vivo and in vitro rodent models to assess human risk. In order to further investigate the species-specific responses elicited by TCDD, temporal gene expression responses in human HepG2, mouse Hepa1c1c7 and rat H4IIE cells were compared. Results Microarray analysis identified a core set of conserved gene expression responses across species consistent with the role of AhR in mediating adaptive metabolic responses. However, significant species-specific as well as species-divergent responses were identified. Computational analysis of the regulatory regions of species-specific and -divergent responses suggests that dioxin response elements (DREs are involved. These results are consistent with in vivo rat vs. mouse species-specific differential gene expression, and more comprehensive comparative DRE searches. Conclusions Comparative analysis of human HepG2, mouse Hepa1c1c7 and rat H4IIE TCDD-elicited gene expression responses is consistent with in vivo rat-mouse comparative gene expression studies, and more comprehensive comparative DRE searches, suggesting that AhR-mediated gene expression is species-specific.

  1. Structural insights into acetylated-histone H4 recognition by the bromodomain-PHD finger module of human transcriptional coactivator CBP.

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    Plotnikov, Alexander N; Yang, Shuai; Zhou, Thomas Jiachi; Rusinova, Elena; Frasca, Antonio; Zhou, Ming-Ming

    2014-02-01

    Bromodomain functions as the acetyl-lysine binding domains to regulate gene transcription in chromatin. Bromodomains are rapidly emerging as new epigenetic drug targets for human diseases. However, owing to their transient nature and modest affinity, histone-binding selectivity of bromodomains has remained mostly elusive. Here, we report high-resolution crystal structures of the bromodomain-PHD tandem module of human transcriptional coactivator CBP bound to lysine-acetylated histone H4 peptides. The structures reveal that the PHD finger serves a structural role in the tandem module and that the bromodomain prefers lysine-acetylated motifs comprising a hydrophobic or aromatic residue at -2 and a lysine or arginine at -3 or -4 position from the acetylated lysine. Our study further provides structural insights into distinct modes of singly and diacetylated histone H4 recognition by the bromodomains of CBP and BRD4 that function differently as a transcriptional coactivator and chromatin organizer, respectively, explaining their distinct roles in control of gene expression in chromatin.

  2. Activation of histamine H4 receptor inhibits TNFα/IMD-0354-induced apoptosis in human salivary NS-SV-AC cells.

    Science.gov (United States)

    Stegajev, Vasili; Kouri, Vesa-Petteri; Salem, Abdelhakim; Rozov, Stanislav; Stark, Holger; Nordström, Dan C E; Konttinen, Yrjö T

    2014-12-01

    Apoptosis is involved in the pathogenesis of Sjögren's syndrome (SS), an autoimmune disease affecting exocrine glands. Our recent studies revealed diminished histamine H4 receptor (H₄R) expression and impaired histamine transport in the salivary gland epithelial cells in SS. The aim was now to test if nanomolar histamine and high-affinity H₄R signaling affect apoptosis of human salivary gland epithelial cell. Simian virus 40-immortalized acinar NS-SV-AC cells were cultured in serum-free keratinocyte medium ± histamine H₄R agonist HST-10. Expression and internalization of H₄R were studied by immunofluorescence staining ± clathrin inhibitor methyl-β-cyclodextrin (MβCD). Apoptosis induced using tumor necrosis factor-α with nuclear factor-κB inhibitor IMD-0354 was studied using phase contrast microscopy, Western blot, flow cytometry and polymerase chain reaction (qRT-PCR). HST-10-stimulated H₄R internalization was inhibited by MβCD. Western blotting revealed diminished phosphorylated c-Jun N-terminal kinase JNK, but unchanged levels of phosphorylated extracellular signal regulated kinase pERK1/2 in H₄R-stimulated samples compared to controls. qRT-PCR showed up-regulated expression of anti-apoptotic B cell lymphoma-extra large/Bcl-xL mRNAs and proteins, whereas pro-apoptotic Bcl-2-associated X protein/BAX remained unchanged in H4R-stimulated samples. H₄R stimulation diminished cleavage of PARP and flow cytometry showed significant dose-dependent inhibitory effect of H₄R stimulation on apoptosis. As far as we know this is the first study showing inhibitory effect of H₄R activation on apoptosis of human salivary gland cells. Diminished H₄R-mediated activation may contribute to loss of immune tolerance in autoimmune diseases and in SS in particular.

  3. B7-H4 expression is elevated in human U251 glioma stem-like cells and is inducible in monocytes cultured with U251 stem-like cell conditioned medium.

    Science.gov (United States)

    Mo, Lian-Jie; Ye, Hong-Xing; Mao, Ying; Yao, Yu; Zhang, Jian-Min

    2013-12-01

    Previous studies indicated that B7-H4, the youngest B7 family, negatively regulates T cell-mediated immunity and is significantly overexpressed in many human tumors. Tumor stem cells are purported to play a role in tumor renewal and resistance to radiation and chemotherapy. However, the link between B7-H4 and tumor stem cells is unclear. In this study, we investigated B7-H4 expression in the medium of human glioma U251 cell cultures. Immunofluorescence results showed that U251 cells cultured in serum-free medium (supplemented with 2% B27, 20 ng/mL epidermal growth factor, 20 ng/mL basic fibroblast growth factor) maintained stem-like cell characteristics, including expression of stem cell marker CD133 and the neural progenitor cell markers nestin and SOX2. In contrast, U251 cells cultured in serum-containing medium highly expressed differentiation marker glial fibrillary acidic protein. Flow cytometry analysis showed serum-free medium-cultured U251 cells expressed higher intracellular B7-H4 than serum-containing medium-cultured U251 cells (24%-35% vs. 8%-11%, P cells revealed moderate expression of B7-H4 after stimulation with conditioned medium from U251 cells cultured in serum-containing medium. Moreover, conditioned medium from U251 stem-like cells had a significant stimulation effect on B7-H4 expression compared with serum-containing conditioned medium (P cells, and conditioned medium from these cells more effectively induced monocytes to express B7-H4 than conditioned medium from U251 cells cultured in the presence of serum. Our results show that U251 stem-like cells may play a more crucial role in tumor immunoloregulation with high expression of B7-H4.

  4. Optimisation of the CT h4S bioassay for detection of human interleukin-4 secreted by mononuclear cells stimulated by phytohaemaglutinin or by human leukocyte antigen mismatched mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Petersen, Søren Lykke; Russell, Charlotte Astrid; Bendtzen, Klaus;

    2002-01-01

    bioassay with regards to specificity, sensitivity, detection limit, and reproducibility. We have found the optimal assay conditions to be 1 x 10 (4) CT.h4S cells/well deprived of IL-4 for 24 h and preincubated for 7 h followed by 18 h of incubation with tritiated methyl-thymidine. In this setting the CT.h4......S bioassay detects 5 pg/ml of human recombinant IL-4 with no detection of IL-2 in concentrations below 500 pg/ml. We have found 72 h of culture optimal for detection of IL-2 and IL-4 produced by human mononuclear cells (MNC) in response to stimulation with phytohaemaglutinin and for detection of IL...... of IL-4 detection was not due to high amounts of soluble IL-4 receptor. With the use of 1x10(6) responder cells/well in HLA-mismatched MLC, we found limited IL-4 accumulation still increasing at day 12. We conclude that the CT.h4S bioassay is a reliable and specific method for quantification of IL-4...

  5. Optimisation of the CT h4S bioassay for detection of human interleukin-4 secreted by mononuclear cells stimulated by phytohaemaglutinin or by human leukocyte antigen mismatched mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Petersen, Søren Lykke; Russell, Charlotte Astrid; Bendtzen, Klaus

    2002-01-01

    Limiting dilution analysis has been used in the context of allogeneic bone marrow transplantation to determine anti-recipient interleukin-2 (IL-2) producing helper T lymphocyte precursor (HTLp) frequencies, which in several studies have been predictive of graft-versus-host disease (GVHD). Recently...... of IL-4 detection was not due to high amounts of soluble IL-4 receptor. With the use of 1x10(6) responder cells/well in HLA-mismatched MLC, we found limited IL-4 accumulation still increasing at day 12. We conclude that the CT.h4S bioassay is a reliable and specific method for quantification of IL-4...... accumulation in cultures of human MNC. The difference in optimal timing for IL-2 (day 3) and IL-4 (>/=day 12) detection and evidence of very low IL-4 producing HTLp frequencies makes the relevance of a combined IL-2/IL-4 HTLp assay questionable....

  6. Cytotoxic effects of 109 reference compounds on rat H4IIE and human HepG2 hepatocytes. III: Mechanistic assays on oxygen consumption with MitoXpress and NAD(P)H production with Alamar Blue™.

    Science.gov (United States)

    Schoonen, Willem G E J; Stevenson, Joe C R; Westerink, Walter M A; Horbach, G Jean

    2012-04-01

    In vitro toxicity screening can reduce the attrition rate of drug candidates in the pharmaceutical industry in the early development process. The focus in this study is to compare the sensitivity for cytotoxicity of a time-resolved fluoro metric oxygen probe with that of a fluoro metric Alamar Blue™ (AB) assay. Both assays measure mitochondrial activity by either oxygen consumption (LUX-A65N-1 (MitoXpress, Luxcel) probe) or NADH/FADH conversion (AB). Both assays were carried out with increasing concentrations of 109 reference compounds using rat H4IIE and human HepG2 hepatocytes at incubation periods of 24, 48 and 72 h. Prior to this study, the influence on medium with either glucose or galactose was studied to analyze the rate of glycolysis and oxygen consumption, which latter process may be impaired in hepatoma cells. Inhibitors of oxygen consumption in combination with a glucose up-take inhibitor showed the largest consumption rate differences in the presence of 5mM of glucose. The choice for the 109 reference compounds was based on the so-called Multicentre Evaluation for In vitro Cytotoxicity (MEIC) and on diverse drug categories. For 59 toxic reference compounds, an evaluation for both assays was carried up to 10(-3)M. Toxicity was demonstrated with MitoXpress for 23 (39%) and 36 (61%) compounds in H4IIE and HepG2 cells, respectively, and with AB for 44 (75%) and 40 (68%) compounds. For 50 more pharmaceutical drugs more physiological concentrations were used up to 3.16×10(-5)M, and only 19 (38%) of these compounds appeared to be toxic in both assays. In conclusion, overall 63 (58%) and 60 (55%) compounds showed toxic effects with the MitoXpress and AB assays on rat H4IIE and human HepG2 hepatocytes, respectively. AB assays were more sensitive with respect to H4IIE cells and MitoXpress assays with respect to HepG2 cells. At all tested time intervals, MitoXpress showed its sensitivity, while AB is more sensitive at 48 and 72 h. With AB more toxic compounds

  7. Main: OCTAMERMOTIFTAH3H4 [PLACE

    Lifescience Database Archive (English)

    Full Text Available OCTAMERMOTIFTAH3H4 S000076 11-May-2006 (last modified) kehi Octamer motif found in ...promoter of wheat (T.a.) histone genes H3 and H4, and corn histone genes H3 and H4; Arabidopsis histone H4; histone-specific oct...amer; About half of the Oct motifs are present together with another element, HexA, TCA ...or CCAAT-box, forming OCES (Oct-containing composite elements); histone; Oct; S-p

  8. 32 CFR 286h.4 - Responsibilities.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Responsibilities. 286h.4 Section 286h.4 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) FREEDOM OF INFORMATION ACT PROGRAM RELEASE OF ACQUISITION-RELATED INFORMATION § 286h.4 Responsibilities. (a) The Under...

  9. Optimisation of the CT h4S bioassay for detection of human interleukin-4 secreted by mononuclear cells stimulated by phytohaemaglutinin or by human leukocyte antigen mismatched mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Petersen, Søren Lykke; Russell, Charlotte Astrid; Bendtzen, Klaus;

    2002-01-01

    bioassay with regards to specificity, sensitivity, detection limit, and reproducibility. We have found the optimal assay conditions to be 1 x 10 (4) CT.h4S cells/well deprived of IL-4 for 24 h and preincubated for 7 h followed by 18 h of incubation with tritiated methyl-thymidine. In this setting the CT.h4...... of IL-4 detection was not due to high amounts of soluble IL-4 receptor. With the use of 1x10(6) responder cells/well in HLA-mismatched MLC, we found limited IL-4 accumulation still increasing at day 12. We conclude that the CT.h4S bioassay is a reliable and specific method for quantification of IL-4......Limiting dilution analysis has been used in the context of allogeneic bone marrow transplantation to determine anti-recipient interleukin-2 (IL-2) producing helper T lymphocyte precursor (HTLp) frequencies, which in several studies have been predictive of graft-versus-host disease (GVHD). Recently...

  10. H4 abrupt event and late Neanderthal presence in Iberia

    Science.gov (United States)

    Sepulchre, Pierre; Ramstein, Gilles; Kageyama, Masa; Vanhaeren, Marian; Krinner, Gerhard; Sánchez-Goñi, María-Fernanda; d'Errico, Francesco

    2007-06-01

    Heinrich event 4 (H4) is well documented in the North Atlantic Ocean and the adjacent continents as a cooling event 39,000 yr before present (BP). To quantify the impact of this event with respect to climate and vegetation over the Iberian Peninsula, we perform numerical experiments using a high-resolution general circulation model forced by sea surface temperatures before and during H4. Our model simulates an expansion of aridity over the peninsula during H4, a desertification of the south, and a replacement of arboreal by herbaceous plants in the north, all of which are in agreement with contemporaneous pollen sequences from marine cores located off the Iberian Peninsula. Our simulations demonstrate that the H4 marine event imprinted drastic changes over Southern Iberia, which would not have favoured its occupation by Anatomically Modern Humans, therefore providing a plausible explanation for the delayed extinction of Neanderthals in this region inferred from the archaeological record.

  11. Histone H4 Lysine 20 methylation

    DEFF Research Database (Denmark)

    Jørgensen, Stine; Schotta, Gunnar; Sørensen, Claus Storgaard

    2013-01-01

    of histones have emerged as key regulators of genomic integrity. Intense research during the past few years has revealed histone H4 lysine 20 methylation (H4K20me) as critically important for the biological processes that ensure genome integrity, such as DNA damage repair, DNA replication and chromatin...... instability, demonstrating the important functions of H4K20 methylation in genome maintenance. In this review, we explain molecular mechanisms underlying these defects and discuss novel ideas for furthering our understanding of genome maintenance in higher eukaryotes....

  12. Reference: OCTAMERMOTIFTAH3H4 [PLACE

    Lifescience Database Archive (English)

    Full Text Available OCTAMERMOTIFTAH3H4 Nakayama T, Sakamoto A, Yang P, Minami M, Fujimoto Y, Ito T, Iwa...buchi M Highly conserved hexamer, octamer and nonamer motifs are positive cis-regulatory elements of the whe

  13. Reference: OCTAMERMOTIFTAH3H4 [PLACE

    Lifescience Database Archive (English)

    Full Text Available OCTAMERMOTIFTAH3H4 Taoka K, Kaya H, Nakayama T, Araki T, Meshi T, Iwabuchi M Identi...fication of three Kinds of mutually related composite elements conferring S phase-specific transcriptional activation Plant J 18:611-623 (1999) PubMed: 10417712; ...

  14. The Histamine H4 Receptor: From Orphan to the Clinic

    Directory of Open Access Journals (Sweden)

    Robin L. Thurmond

    2015-03-01

    Full Text Available The histamine H4 receptor (H4R was first noted as a sequence in genomic databases that had features of a G-protein coupled receptor. This putative receptor was found to bind histamine consistent with its homology to other histamine receptors and thus became the fourth member of the histamine receptor family. Due to the previous success of drugs that target the H1 and H2 receptors, an effort was made to understand the function of this receptor and determine if it represented a drug target. Taking advantage of the vast literature on histamine, a search for histamine activity that did not appear to be mediated by the other three histamine receptors was undertaken. From this asthma and pruritus emerged as areas of particular interest. Histamine has long been suspected to play a role in the pathogenesis of asthma, but antihistamines that target the H1 and H2 receptors have not been shown to be effective for this condition. The use of selective ligands in animal models of asthma has now potentially filled this gap by showing a role for the H4R in mediating lung function and inflammation. A similar story exists for chronic pruritus associated with conditions such as atopic dermatitis. Antihistamines that target the H1 receptor are effective in reducing acute pruritus, but are ineffective in pruritus experienced by patients with atopic dermatitis. As for asthma, animal models have now suggested a role for the H4R in mediating pruritic responses, with antagonists to the H4R reducing pruritus in a number of different conditions. The anti-pruritic effect of H4R antagonists has recently been shown in human clinical studies, validating the preclinical findings in the animal models. A selective H4R antagonist inhibited histamine-induced pruritus in health volunteers and reduced pruritus in patients with atopic dermatitis. The history to date of the H4R provides an excellent example of the deorphanization of a novel receptor and the translation of this into

  15. DNA Mismatch Repair Interacts with CAF-1- and ASF1A-H3-H4-dependent Histone (H3-H4)2 Tetramer Deposition.

    Science.gov (United States)

    Rodriges Blanko, Elena; Kadyrova, Lyudmila Y; Kadyrov, Farid A

    2016-04-22

    DNA mismatch repair (MMR) is required for the maintenance of genome stability and protection of humans from several types of cancer. Human MMR occurs in the chromatin environment, but little is known about the interactions between MMR and the chromatin environment. Previous research has suggested that MMR coincides with replication-coupled assembly of the newly synthesized DNA into nucleosomes. The first step in replication-coupled nucleosome assembly is CAF-1-dependent histone (H3-H4)2 tetramer deposition, a process that involves ASF1A-H3-H4 complex. In this work we used reconstituted human systems to investigate interactions between MMR and CAF-1- and ASF1A-H3-H4-dependent histone (H3-H4)2 tetramer deposition. We have found that MutSα inhibits CAF-1- and ASF1A-H3-H4-dependent packaging of a DNA mismatch into a tetrasome. This finding supports the idea that MMR occurs before the DNA mismatch is packaged into the tetrasome. Our experiments have also revealed that CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers does not interfere with MMR reactions. In addition, we have established that unnecessary degradation of the discontinuous strand that takes place in both DNA polymerase δ (Pol δ)- and DNA polymerase ϵ (Pol ϵ)-dependent MMR reactions is suppressed by CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers. These data suggest that CAF-1- and ASF1A-H3-H4-dependent deposition of the histone (H3-H4)2 tetramers is compatible with MMR and protects the discontinuous daughter strand from unnecessary degradation by MMR machinery.

  16. 2-GHz band CW and W-CDMA modulated radiofrequency fields have no significant effect on cell proliferation and gene expression profile in human cells.

    Science.gov (United States)

    Sekijima, Masaru; Takeda, Hiroshi; Yasunaga, Katsuaki; Sakuma, Noriko; Hirose, Hideki; Nojima, Toshio; Miyakoshi, Junji

    2010-01-01

    We investigated the mechanisms by which radiofrequency (RF) fields exert their activity, and the changes in both cell proliferation and the gene expression profile in the human cell lines, A172 (glioblastoma), H4 (neuroglioma), and IMR-90 (fibroblasts from normal fetal lung) following exposure to 2.1425 GHz continuous wave (CW) and Wideband Code Division Multiple Access (W-CDMA) RF fields at three field levels. During the incubation phase, cells were exposed at the specific absorption rates (SARs) of 80, 250, or 800 mW/kg with both CW and W-CDMA RF fields for up to 96 h. Heat shock treatment was used as the positive control. No significant differences in cell growth or viability were observed between any test group exposed to W-CDMA or CW radiation and the sham-exposed negative controls. Using the Affymetrix Human Genome Array, only a very small (CDMA RF fields for up to 96 h did not act as an acute cytotoxicant in either cell proliferation or the gene expression profile. These results suggest that RF exposure up to the limit of whole-body average SAR levels as specified in the ICNIRP guidelines is unlikely to elicit a general stress response in the tested cell lines under these conditions.

  17. Interaktionen von Histamin H1-Rezeptoragonisten und –antagonisten mit dem humanen Histamin H4-Rezeptor

    OpenAIRE

    2012-01-01

    Der humane Histamin H(4)-Rezeptor (hH(4)R) zeichnet sich durch hohe konstitutive Aktivität aus und ist wie der humane H(1)-Rezeptor (hH(1)R) in die Pathogenese von allergischen Reaktionen vom Typ I involviert. Die Ziele der Untersuchungen waren die Evaluierung des Wertes von dualen H(1)/H(4)R Antagonisten als antiallergische Medikamente und die Klärung der Frage, ob H(1)R Liganden an den hH(4)R binden. Am in Sf9-Insektenzellen exprimierten hH(4)R zeigten 18 H(1)R Antagonisten und 22 H(1)R Ago...

  18. B7-H4 as a protective shield for pancreatic islet beta cells

    Institute of Scientific and Technical Information of China (English)

    Annika; C; Sun; Dawei; Ou; Dan; S; Luciani; Garth; L; Warnock

    2014-01-01

    Auto- and alloreactive T cells are major culprits that damage β-cells in type 1 diabetes(T1D) and islet transplantation. Current immunosuppressive drugs can alleviate immune-mediated attacks on islets. T cell co-stimulation blockade has shown great promise in autoimmunity and transplantation as it solely targets activated T cells, and therefore avoids toxicity of current immunosuppressive drugs. An attractive approach is offered by the newly-identified negative T cell cosignaling molecule B7-H4 which is expressed in normal human islets, and its expression co-localizes with insulin. A concomitant decrease in B7-H4/insulin colocalization is observed in human type 1 diabetic islets. B7-H4 may play protective roles in the pancreatic islets, preserving their function and survival. In this review we outline the protective effect of B7-H4 in the contexts of T1 D, islet cell transplantation, and potentially type 2 diabetes. Current evidence offers encouraging data regarding the role of B7-H4 in reversal of autoimmune diabetes and donor-specific islet allograft tolerance. Additionally, unique expression of B7-H4 may serve as a potential biomarker for the development of T1 D. Futurestudies should continue to focus on the islet-specific effects of B7-H4 with emphasis on mechanistic pathways in order to promote B7-H4 as a potential therapy and cure for T1 D.

  19. 26 CFR 1.642(h)-4 - Allocation.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Allocation. 1.642(h)-4 Section 1.642(h)-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Estates, Trusts, and Beneficiaries § 1.642(h)-4 Allocation. The carryovers and...

  20. H+4形成机制的初步研究%Study on the formation mechanism of H+4

    Institute of Scientific and Technical Information of China (English)

    汪华英; 张霞; 王玉宝

    2001-01-01

    A penning ion trap is used to generate H+n(n≤4)at different trapped interval. It confirms that H+4 is stable cluster ion and that H+4is generated by impact reaction H+3+H+H2H+4+H2;H+2+H2H+4.%利用Penning ion trap 存储和累积离子的功能,获得不同延时(即反应时间)的离子谱H+n(n≤4),不仅进一步证实了H+4具有稳定结构的理论预言,而且经分析得出,H+4是经碰撞反应H+2 +H2 → H+4; H+3+H+H2 → H+4+ H2产生的。

  1. H4K44 Acetylation Facilitates Chromatin Accessibility during Meiosis.

    Science.gov (United States)

    Hu, Jialei; Donahue, Greg; Dorsey, Jean; Govin, Jérôme; Yuan, Zuofei; Garcia, Benjamin A; Shah, Parisha P; Berger, Shelley L

    2015-12-01

    Meiotic recombination hotspots are associated with histone post-translational modifications and open chromatin. However, it remains unclear how histone modifications and chromatin structure regulate meiotic recombination. Here, we identify acetylation of histone H4 at Lys44 (H4K44ac) occurring on the nucleosomal lateral surface. We show that H4K44 is acetylated at pre-meiosis and meiosis and displays genome-wide enrichment at recombination hotspots in meiosis. Acetylation at H4K44 is required for normal meiotic recombination, normal levels of double-strand breaks (DSBs) during meiosis, and optimal sporulation. Non-modifiable H4K44R results in increased nucleosomal occupancy around DSB hotspots. Our results indicate that H4K44ac functions to facilitate chromatin accessibility favorable for normal DSB formation and meiotic recombination.

  2. In vitro Activity and Function of B7-H4-Ig Fusion Protein

    DEFF Research Database (Denmark)

    Rasmussen, Susanne B; Kosicki, Michael; Svendsen, Signe Goul

    2013-01-01

    B7-H4 has been shown to inhibit T cell proliferation, cytokine production and cell cycle in vitro. B7-H4 deficient mice develop exacerbated disease in the mouse models of Rheumatoid Arthritis (RA), Type 1 Diabetes (T1D) and Experimental Autoimmune Encephalomyelitis (EAE). On the other hand, B7-H4......-Ig fusion protein has been documented to assuage the symptoms in mouse models of RA, T1D, and multiple sclerosis in vivo. In the present study, B7-H4-Ig bound to the majority of human peripheral blood monocytes and NK cells, but not to either normal or activated T cells. B7-H4-Ig fusion protein...... was assayed for its effects in allogeneic mixed lymphocyte culture (MLC) systems. Soluble B7- H4-Ig had no significant effect in the MLC, but with a tendency to promote allogeneic response. Immobilized, but not soluble B7-H4-Ig inhibited plastic bound anti-CD3 mediated activation of T cells. This inhibition...

  3. LDLR expression and localization are altered in mouse and human cell culture models of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Jose F Abisambra

    Full Text Available BACKGROUND: Alzheimer's disease (AD is a chronic neurodegenerative disorder and the most common form of dementia. The major molecular risk factor for late-onset AD is expression of the epsilon-4 allele of apolipoprotein E (apoE, the major cholesterol transporter in the brain. The low-density lipoprotein receptor (LDLR has the highest affinity for apoE and plays an important role in brain cholesterol metabolism. METHODOLOGY/PRINCIPAL FINDINGS: Using RT-PCR and western blotting techniques we found that over-expression of APP caused increases in both LDLR mRNA and protein levels in APP transfected H4 neuroglioma cells compared to H4 controls. Furthermore, immunohistochemical experiments showed aberrant localization of LDLR in H4-APP neuroglioma cells, Abeta-treated primary neurons, and in the PSAPP transgenic mouse model of AD. Finally, immunofluorescent staining of LDLR and of gamma- and alpha-tubulin showed a change in LDLR localization preferentially away from the plasma membrane that was paralleled by and likely the result of a disruption of the microtubule-organizing center and associated microtubule network. CONCLUSIONS/SIGNIFICANCE: These data suggest that increased APP expression and Abeta exposure alters microtubule function, leading to reduced transport of LDLR to the plasma membrane. Consequent deleterious effects on apoE uptake and function will have implications for AD pathogenesis and/or progression.

  4. 42 CFR 52h.4 - Composition of peer review groups.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Composition of peer review groups. 52h.4 Section... PEER REVIEW OF RESEARCH GRANT APPLICATIONS AND RESEARCH AND DEVELOPMENT CONTRACT PROJECTS § 52h.4 Composition of peer review groups. (a) To the extent applicable, the selection and appointment of members...

  5. High pressure oxidation of C2H4/NO mixtures

    DEFF Research Database (Denmark)

    Giménez-López, J.; Alzueta, M.U.; Rasmussen, C.T.

    2011-01-01

    An experimental and kinetic modeling study of the interaction between C2H4 and NO has been performed under flow reactor conditions in the intermediate temperature range (600–900K), high pressure (60bar), and for stoichiometries ranging from reducing to oxidizing conditions. The main reaction...... pathways of the C2H4/O2/NOx conversion, the capacity of C2H4 to remove NO, and the influence of the presence of NOx on the C2H4 oxidation are analyzed. Compared to the C2H4/O2 system, the presence of NOx shifts the onset of reaction 75–150K to lower temperatures. The mechanism of sensitization involves...

  6. Genetic characterization of avian influenza subtype H4N6 and H4N9 from live bird market, Thailand

    Directory of Open Access Journals (Sweden)

    Kitikoon Pravina

    2011-03-01

    Full Text Available Abstract A one year active surveillance program for influenza A viruses among avian species in a live-bird market (LBM in Bangkok, Thailand was conducted in 2009. Out of 970 samples collected, influenza A virus subtypes H4N6 (n = 2 and H4N9 (n = 1 were isolated from healthy Muscovy ducks. All three viruses were characterized by whole genome sequencing with subsequent phylogenetic analysis and genetic comparison. Phylogenetic analysis of all eight viral genes showed that the viruses clustered in the Eurasian lineage of influenza A viruses. Genetic analysis showed that H4N6 and H4N9 viruses display low pathogenic avian influenza characteristics. The HA cleavage site and receptor binding sites were conserved and resembled to LPAI viruses. This study is the first to report isolation of H4N6 and H4N9 viruses from birds in LBM in Thailand and shows the genetic diversity of the viruses circulating in the LBM. In addition, co-infection of H4N6 and H4N9 in the same Muscovy duck was observed.

  7. The inhibitory role of b7-h4 in antitumor immunity: association with cancer progression and survival.

    Science.gov (United States)

    He, Changjun; Qiao, Haiquan; Jiang, Hongchi; Sun, Xueying

    2011-01-01

    B7-H4 is one of the most recently identified members of B7 superfamily of costimulatory molecules serving as an inhibitory modulator of T-cell response. B7-H4 is broadly expressed in human peripheral tissues and inducibly expressed in immune cells. The expression of B7-H4 has been observed in various types of human cancer tissues, and its soluble form has been detected in blood samples from cancer patients. However, its precise physiological role is still elusive, as its receptor has not been identified and the expression levels are not consistent. This paper summarizes the pertinent data on the inhibitory role of B7-H4 in antitumor immunity and its association with cancer progression and survival in human patients. The paper also discusses the clinical significance of investigating B7-H4 as potential markers for cancer diagnosis and prognosis, and as therapeutic targets.

  8. Dust Charging in Electronegative SiH4 Plasmas

    Institute of Scientific and Technical Information of China (English)

    DUAN Ping; WANG Zheng-Xiong; LIU Yue; LIU Jin-Yuan; WANG Xiao-Gang

    2005-01-01

    @@ We theoretically investigate the dust charging in electronegative silane (SiH4) plasmas, taking into account the effects of UV photodetachment. It is found that UV photodetachment could significantly lower the dust negative charge and even makes dust grains be positively charged under some special conditions. In addition, the other parameters, involving the negative ion and dust number densities, electron temperature and dust radius, have great effects upon the dust charging.

  9. H$_4$: A Challenging System For Natural Orbital Functional Approximations

    CERN Document Server

    Ramos-Cordoba, Eloy; Piris, Mario; Matito, Eduard

    2015-01-01

    The correct description of nondynamic correlation by electronic structure methods not belonging to the multireference family is a challenging issue. The transition of $D_{2h}$ to $D_{4h}$ symmetry in H$_4$ molecule is among the most simple archetypal examples to illustrate the consequences of missing nondynamic correlation effects. The resurge of interest in density matrix functional methods has brought several new methods including the family of Piris Natural Orbital Functionals (PNOF). In this work we compare PNOF5 and PNOF6, which include nondynamic electron correlation effects to some extent, with other standard ab initio methods in the H$_4$ $D_{4h}/D_{2h}$ potential energy surface. Thus far, the wrongful behavior of single-reference methods at the $D_{2h}-D_{4h}$ transition of H$_4$ has been attributed to wrong account of nondynamic correlation effects, whereas in geminal-based approaches it has been assigned to a wrong coupling of spins and the localized nature of the orbitals. We will show that actual...

  10. Chromatin structure determines accessibility of a hairpin polyamide-chlorambucil conjugate at histone H4 genes in pancreatic cancer cells.

    Science.gov (United States)

    Jespersen, Christine; Soragni, Elisabetta; James Chou, C; Arora, Paramjit S; Dervan, Peter B; Gottesfeld, Joel M

    2012-06-15

    We have shown that a specific pyrrole-imidazole polyamide-DNA alkylator (chlorambucil) conjugate, 1R-Chl, alters the growth characteristics of various cancer cell lines in culture, and causes these cells to arrest in the G2/M stage of the cell cycle, without apparent cytotoxicity. This molecule has also shown efficacy in several mouse xenograft models, preventing tumor growth. Previous microarray studies have suggested that members of the histone H4 gene family, H4c and H4j/k, are the primary targets of this molecule, leading to reduced histone mRNA synthesis and growth arrest in cancer cells. In the present study, we examine the effects of 1R-Chl on transcription of other members of the H4 gene family, with the result that mRNA transcription of most genomic copies of H4 are down-regulated by 1R-Chl in a human pancreatic cancer cell line (MIA PaCa-2), but not in a cell line of non-cancerous origin (HEK293 cells). The basis for this differential effect is likely an open chromatin conformation within the H4 genes in cancer cells. Chromatin immunoprecipitation experiments show increased histone acetylation on the histone H4 genes in cancer cells, compared to HEK293 cells, explaining the differential activity of this molecule in cancer versus non-cancer cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. Zoom into the tracking detector and the LAr calorimeter where its detailed structure is highlighted. The tracks and clusters of the two electron pairs are colored red and blue, respectively.

  12. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. The tracks and clusters of the two electron pairs are colored red and blue, respectively.

  13. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. Zoom into the tracking detector. The tracks and clusters of the two electron pairs are colored red and blue, respectively.

  14. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. The tracks of the two electron pairs are colored red, the clusters in the LAr calorimeter are colored darkgreen.

  15. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. The tracks and clusters of the two electron pairs are colored red and blue, respectively.

  16. Evidence of infection with H4 and H11 avian influenza viruses among Lebanese chicken growers.

    Directory of Open Access Journals (Sweden)

    Ghazi Kayali

    Full Text Available Human infections with H5, H7, and H9 avian influenza viruses are well documented. Exposure to poultry is the most important risk factor for humans becoming infected with these viruses. Data on human infection with other low pathogenicity avian influenza viruses is sparse but suggests that such infections may occur. Lebanon is a Mediterranean country lying under two major migratory birds flyways and is home to many wild and domestic bird species. Previous reports from this country demonstrated that low pathogenicity avian influenza viruses are in circulation but highly pathogenic H5N1 viruses were not reported. In order to study the extent of human infection with avian influenza viruses in Lebanon, we carried out a seroprevalence cross-sectional study into which 200 poultry-exposed individuals and 50 non-exposed controls were enrolled. We obtained their sera and tested it for the presence of antibodies against avian influenza viruses types H4 through H16 and used a questionnaire to collect exposure data. Our microneutralization assay results suggested that backyard poultry growers may have been previously infected with H4 and H11 avian influenza viruses. We confirmed these results by using a horse red blood cells hemagglutination inhibition assay. Our data also showed that farmers with antibodies against each virus type clustered in a small geographic area suggesting that unrecognized outbreaks among birds may have led to these human infections. In conclusion, this study suggests that occupational exposure to chicken is a risk factor for infection with avian influenza especially among backyard growers and that H4 and H11 influenza viruses may possess the ability to cross the species barrier to infect humans.

  17. Structure-function studies of histone H3/H4 tetramer maintenance during transcription by chaperone Spt2.

    Science.gov (United States)

    Chen, Shoudeng; Rufiange, Anne; Huang, Hongda; Rajashankar, Kanagalaghatta R; Nourani, Amine; Patel, Dinshaw J

    2015-06-15

    Cells use specific mechanisms such as histone chaperones to abrogate the inherent barrier that the nucleosome poses to transcribing polymerases. The current model postulates that nucleosomes can be transiently disrupted to accommodate passage of RNA polymerases and that histones H3 and H4 possess their own chaperones dedicated to the recovery of nucleosomes. Here, we determined the crystal structure of the conserved C terminus of human Suppressors of Ty insertions 2 (hSpt2C) chaperone bound to an H3/H4 tetramer. The structural studies demonstrate that hSpt2C is bound to the periphery of the H3/H4 tetramer, mimicking the trajectory of nucleosomal-bound DNA. These structural studies have been complemented with in vitro binding and in vivo functional studies on mutants that disrupt key intermolecular contacts involving two acidic patches and hydrophobic residues on Spt2C. We show that contacts between both human and yeast Spt2C with the H3/H4 tetramer are required for the suppression of H3/H4 exchange as measured by H3K56ac and new H3 deposition. These interactions are also crucial for the inhibition of spurious transcription from within coding regions. Together, our data indicate that Spt2 interacts with the periphery of the H3/H4 tetramer and promotes its recycling in the wake of RNA polymerase. © 2015 Chen et al.; Published by Cold Spring Harbor Laboratory Press.

  18. Physical and spectroscopic properties of pure C2H4 and CH4:C2H4 ices

    Science.gov (United States)

    Molpeceres, Germán; Satorre, Miguel Angel; Ortigoso, Juan; Zanchet, Alexandre; Luna, Ramón; Millán, Carlos; Escribano, Rafael; Tanarro, Isabel; Herrero, Víctor J.; Maté, Belén

    2017-04-01

    Physical and spectroscopic properties of ices of C2H4 and CH4:C2H4 mixtures with 3:1, 1:1 and 1:3 ratios have been investigated at 30 K. Two laboratories are involved in this work. In one of them, the density and refractive index of the samples have been measured by using a cryogenic quartz microbalance and laser interferometric techniques. In the other one, IR spectra have been recorded in the near- and mid-infrared regions, and band shifts with respect to the pure species, band strengths of the main bands, and the optical constants in both regions have been determined. Previous data on ethylene and the mixtures studied here were scarce. For methane, both the wavenumbers and band strengths have been found to follow a regular pattern of decrease with increasing dilution, but no pattern has been detected for ethylene vibrations. The method employed for the preparation of the samples, by vapour deposition under vacuum, is thought to be adequate to mimic the structure of astrophysical ices. Possible astrophysical implications, especially by means of the optical constants reported here, have been discussed.

  19. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. The tracks and clusters of the two electron pairs are colored red and blue, respectively. The three displays on the right-hand side show the r-phi view of the event (top), a zoom into the vertex region, indicating that the 4 electrons originate from the same primary vertex (middle), and a Lego plot indicating the amount of transverse energy Et measured in the calorimeters (bottom).

  20. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display (side view) of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. The tracks of the two electron pairs are colored red and blue, respectively. Electron clusters in the LAr calorimeter are colored darkgreen. The three displays on the right-hand side show the r-phi view of the event (top), a zoom into the vertex region, indicating that the 4 electrons originate from the same primary vertex (middle), and a Lego plot indicating the amount of transverse energy Et measured in the calorimeters (bottom).

  1. Cloning and Molecular Characterization of the Schistosoma mansoni Genes RbAp48 and Histone H4

    Directory of Open Access Journals (Sweden)

    Patrícia P Souza

    2002-10-01

    Full Text Available The human nuclear protein RbAp48 is a member of the tryptophan/aspartate (WD repeat family, which binds to the retinoblastoma (Rb protein. It also corresponds to the smallest subunit of the chromatin assembly factor and is able to bind to the helix 1 of histone H4, taking it to the DNA in replication. A cDNA homologous to the human gene RbAp48 was isolated from a Schistosoma mansoni adult worm library and named SmRbAp48. The full length sequence of SmRbAp48 cDNA is 1036 bp long, encoding a protein of 308 amino acids. The transcript of SmRbAp48 was detected in egg, cercariae and schistosomulum stages. The protein shows 84% similarity with the human RbAp48, possessing four WD repeats on its C-terminus. A hypothetical tridimensional structure for the SmRbAp48 C-terminal domain was constructed by computational molecular modeling using the b-subunit of the G protein as a model. To further verify a possible interaction between SmRbAp48 and S. mansoni histone H4, the histone H4 gene was amplified from adult worm genomic DNA using degenerated primers. The gene fragment of SmH4 is 294 bp long, encoding a protein of 98 amino acids which is 100% identical to histone H4 from Drosophila melanogaster.

  2. Effects of histone acetylation and H3K4 methylation on PRA/PRB in human uterine smooth muscle cells during pregnancy%组蛋白H3、H4乙酰化及H3K4甲基化对人妊娠子宫平滑肌细胞PRA/PRB的影响

    Institute of Scientific and Technical Information of China (English)

    罗慧; 陈诚; 梁志清

    2014-01-01

    目的 通过组蛋白去乙酰化酶抑制剂(trichostatin A,TSA)、H3 K4甲基化酶抑制剂(5’-deoxy-5’-methylthioadenosine,MTA)处理人妊娠子宫平滑肌细胞,干预组蛋白H3、H4乙酰化及H3K4甲基化水平,探讨组蛋白H3、H4乙酰化及H3K4甲基化对人妊娠子宫平滑肌细胞PRA/PRB的影响.方法 分离纯化人妊娠子宫平滑肌细胞(n=16),免疫组化定位孕激素受体(progesterone receptor,PR)及孕激素受体B(progesterone receptor B,PRB)在子宫平滑肌细胞核的表达.分别利用不同浓度TSA、MTA对其进行处理,Real-time PCR检测PR、PRA、PRB mRNA的表达;染色质免疫共沉淀技术(Chromatin immunoprecipitation,ChIP)比较处理前后PRA、PRB启动子区H3、H4乙酰化及H3K4三甲基化水平.结果 TSA可使PRA/PRB明显增高(P<0.05),使PRA启动子区H3、H4乙酰化水平明显上升(P<0.05).MTA可使PRA/PRB明显下降(P<0.05),PRA启动子区H3K4乙酰化水平明显下降(P<0.05).两种药物的干预主要通过对PRA的调控来调节PRA/PRB比值.结论 组蛋白H3、H4乙酰化和H3K4甲基化均可使人妊娠子宫平滑肌细胞PRA/PRB比值发生改变,可能参与“功能性孕激素撤退”机制的调节.

  3. Synergistic effects of host B7-H4 deficiency and gemcitabine treatment on tumor regression and anti-tumor T cell immunity in a mouse model.

    Science.gov (United States)

    Leung, Joanne; St-Onge, Philippe; Stagg, John; Suh, Woong-Kyung

    2017-04-01

    B7-H4 (B7x/B7S1), a B7 family inhibitor of T cell activity, is expressed in multiple human cancers and correlates with decreased infiltrating lymphocytes and poor prognosis. In murine models, tumor-expressed B7-H4 enhances tumor growth and reduces T cell immunity, and blockade of tumor-B7-H4 rescues T cell activity and lowers tumor burden. This implicates B7-H4 as a target for cancer immunotherapy, yet limits the efficacy of B7-H4 blockade exclusively to patients with B7-H4+ tumors. Given the expression of B7-H4 on host immune cells, we have previously shown that BALB/c mice lacking host B7-H4 have enhanced anti-tumor profiles, yet similar 4T1 tumor growth relative to control. Given that T cell-mediated immunotherapies work best for tumors presenting tumor-associated neoantigens, we further investigated the function of host B7-H4 in the growth of a more immunogenic derivative, 4T1-12B, which is known to elicit strong anti-tumor CD8 T cell responses due to expression of a surrogate tumor-specific antigen, firefly luciferase. Notably, B7-H4 knockout hosts not only mounted greater tumor-associated anti-tumor T cell responses, but also displayed reduced tumors. Additionally, B7-H4-deficiency synergized with gemcitabine to further inhibit tumor growth, often leading to tumor eradication and the generation of protective T cell immunity. These findings imply that inhibition of host B7-H4 can enhance anti-tumor T cell immunity in immunogenic cancers, and can be combined with other anti-cancer therapies to further reduce tumor burden regardless of tumor-B7-H4 positivity.

  4. CAF-1-induced oligomerization of histones H3/H4 and mutually exclusive interactions with Asf1 guide H3/H4 transitions among histone chaperones and DNA.

    Science.gov (United States)

    Liu, Wallace H; Roemer, Sarah C; Port, Alex M; Churchill, Mair E A

    2012-12-01

    Anti-silencing function 1 (Asf1) and Chromatin Assembly Factor 1 (CAF-1) chaperone histones H3/H4 during the assembly of nucleosomes on newly replicated DNA. To understand the mechanism of histone H3/H4 transfer among Asf1, CAF-1 and DNA from a thermodynamic perspective, we developed and employed biophysical approaches using full-length proteins in the budding yeast system. We find that the C-terminal tail of Asf1 enhances the interaction of Asf1 with CAF-1. Surprisingly, although H3/H4 also enhances the interaction of Asf1 with the CAF-1 subunit Cac2, H3/H4 forms a tight complex with CAF-1 exclusive of Asf1, with an affinity weaker than Asf1-H3/H4 or H3/H4-DNA interactions. Unlike Asf1, monomeric CAF-1 binds to multiple H3/H4 dimers, which ultimately promotes the formation of (H3/H4)(2) tetramers on DNA. Thus, transition of H3/H4 from the Asf1-associated dimer to the DNA-associated tetramer is promoted by CAF-1-induced H3/H4 oligomerization.

  5. Structure and function of the histone chaperone CIA/ASF1 complexed with histones H3 and H4.

    Science.gov (United States)

    Natsume, Ryo; Eitoku, Masamitsu; Akai, Yusuke; Sano, Norihiko; Horikoshi, Masami; Senda, Toshiya

    2007-03-15

    CIA (CCG1-interacting factor A)/ASF1, which is the most conserved histone chaperone among the eukaryotes, was genetically identified as a factor for an anti-silencing function (Asf1) by yeast genetic screening. Shortly after that, the CIA-histone-H3-H4 complex was isolated from Drosophila as a histone chaperone CAF-1 stimulator. Human CIA-I/II (ASF1a/b) was identified as a histone chaperone that interacts with the bromodomain-an acetylated-histone-recognizing domain-of CCG1, in the general transcription initiation factor TFIID. Intensive studies have revealed that CIA/ASF1 mediates nucleosome assembly by forming a complex with another histone chaperone in human cells and yeast, and is involved in DNA replication, transcription, DNA repair and silencing/anti-silencing in yeast. CIA/ASF1 was shown as a major storage chaperone for soluble histones in proliferating human cells. Despite all these biochemical and biological functional analyses, the structure-function relationship of the nucleosome assembly/disassembly activity of CIA/ASF1 has remained elusive. Here we report the crystal structure, at 2.7 A resolution, of CIA-I in complex with histones H3 and H4. The structure shows the histone H3-H4 dimer's mutually exclusive interactions with another histone H3-H4 dimer and CIA-I. The carboxy-terminal beta-strand of histone H4 changes its partner from the beta-strand in histone H2A to that of CIA-I through large conformational change. In vitro functional analysis demonstrated that CIA-I has a histone H3-H4 tetramer-disrupting activity. Mutants with weak histone H3-H4 dimer binding activity showed critical functional effects on cellular processes related to transcription. The histone H3-H4 tetramer-disrupting activity of CIA/ASF1 and the crystal structure of the CIA/ASF1-histone-H3-H4 dimer complex should give insights into mechanisms of both nucleosome assembly/disassembly and nucleosome semi-conservative replication.

  6. Entamoeba histolytica: protein arginine transferase 1a methylates arginine residues and potentially modify the H4 histone.

    Science.gov (United States)

    Borbolla-Vázquez, Jessica; Orozco, Esther; Betanzos, Abigail; Rodríguez, Mario A

    2015-04-10

    In eukaryotes, histone arginine methylation associates with both active and repressed chromatin states depending on the residues involved and the status of methylation. Even when the amino-terminus of Entamoeba histolytica histones diverge from metazoan sequences, these regions contain arginine residues that are potential targets for methylation. However, histone arginine methylation as well as the activity of arginine methyltransferases (PRMTs) has not been studied in this parasite. The aim of this work was to examine the dimethylation of arginine 3 of H4 histone (H4R3me2) and to identify the parasite PRMT that could be responsible for this modification (EhPRMT1). To examine the presence of H4R3me2 in E histolytica, we performed Western blot and immunofluorescence assays on trophozoites using an antibody against this epigenetic mark. To recognize the PRMT1 enzyme of this parasite that possibly perform that modification, we first performed a phylogenetic analysis of E. histolytica and human PRMTs. RT-PCR assays were carried out to analyze the expression of the putative PRMT1 genes. One of these genes was cloned and expressed in Escherichia coli. The recombinant protein was tested by its recognition by an antibody against human PRMT1 and in its ability to form homodimers and to methylate commercial histones. The arginine 3 of human H4, which is subjected to post translational methylation, was aligned with the arginine 8 of E. histolytica H4, suggesting that this residue could be methylated. The recognition of an 18 kDa nuclear protein of E. histolytica by an antibody against H4R3me2 confirmed this assumption. We found that this parasite expresses three phylogenetic and structural proteins related to PRMT1. Antibodies against the human PRMT1 detected E. histolytica proteins in cytoplasm and nuclei and recognized a recombinant PRMT1 of this parasite. The recombinant protein was able to form homodimers and homotetramers and displayed methyltransferase activity on

  7. Structural plasticity of histones H3-H4 facilitates their allosteric exchange between RbAp48 and ASF1.

    Science.gov (United States)

    Zhang, Wei; Tyl, Marek; Ward, Richard; Sobott, Frank; Maman, Joseph; Murthy, Andal S; Watson, Aleksandra A; Fedorov, Oleg; Bowman, Andrew; Owen-Hughes, Tom; El Mkami, Hassane; Murzina, Natalia V; Norman, David G; Laue, Ernest D

    2013-01-01

    The mechanisms by which histones are disassembled and reassembled into nucleosomes and chromatin structure during DNA replication, repair and transcription are poorly understood. A better understanding of the processes involved is, however, crucial if we are to understand whether and how histone variants and post-translationally modified histones are inherited in an epigenetic manner. To this end we have studied the interaction of the histone H3-H4 complex with the human retinoblastoma-associated protein RbAp48 and their exchange with a second histone chaperone, anti-silencing function protein 1 (ASF1). Exchange of histones H3-H4 between these two histone chaperones has a central role in the assembly of new nucleosomes, and we show here that the H3-H4 complex has an unexpected structural plasticity, which is important for this exchange.

  8. Sequential application of ligand and structure based modeling approaches to index chemicals for their hH4R antagonism.

    Directory of Open Access Journals (Sweden)

    Matteo Pappalardo

    Full Text Available The human histamine H4 receptor (hH4R, a member of the G-protein coupled receptors (GPCR family, is an increasingly attractive drug target. It plays a key role in many cell pathways and many hH4R ligands are studied for the treatment of several inflammatory, allergic and autoimmune disorders, as well as for analgesic activity. Due to the challenging difficulties in the experimental elucidation of hH4R structure, virtual screening campaigns are normally run on homology based models. However, a wealth of information about the chemical properties of GPCR ligands has also accumulated over the last few years and an appropriate combination of these ligand-based knowledge with structure-based molecular modeling studies emerges as a promising strategy for computer-assisted drug design. Here, two chemoinformatics techniques, the Intelligent Learning Engine (ILE and Iterative Stochastic Elimination (ISE approach, were used to index chemicals for their hH4R bioactivity. An application of the prediction model on external test set composed of more than 160 hH4R antagonists picked from the chEMBL database gave enrichment factor of 16.4. A virtual high throughput screening on ZINC database was carried out, picking ∼ 4000 chemicals highly indexed as H4R antagonists' candidates. Next, a series of 3D models of hH4R were generated by molecular modeling and molecular dynamics simulations performed in fully atomistic lipid membranes. The efficacy of the hH4R 3D models in discrimination between actives and non-actives were checked and the 3D model with the best performance was chosen for further docking studies performed on the focused library. The output of these docking studies was a consensus library of 11 highly active scored drug candidates. Our findings suggest that a sequential combination of ligand-based chemoinformatics approaches with structure-based ones has the potential to improve the success rate in discovering new biologically active GPCR drugs and

  9. File list: His.ALL.05.H4tetraac.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.ALL.05.H4tetraac.AllCell ce10 Histone H4tetraac All cell types SRX059244,SRX059...245,SRX747305,SRX747306 http://dbarchive.biosciencedbc.jp/kyushu-u/ce10/assembled/His.ALL.05.H4tetraac.AllCell.bed ...

  10. File list: His.Lar.10.H4tetraac.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.10.H4tetraac.AllCell ce10 Histone H4tetraac Larvae SRX059244,SRX059245,SRX7...47305,SRX747306 http://dbarchive.biosciencedbc.jp/kyushu-u/ce10/assembled/His.Lar.10.H4tetraac.AllCell.bed ...

  11. File list: His.ALL.20.H4.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.ALL.20.H4.AllCell hg19 Histone H4 All cell types SRX502821,SRX684267,SRX502824,...SRX502825,SRX502823,SRX502820,SRX502822 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.ALL.20.H4.AllCell.bed ...

  12. Alterations of global histone H4K20 methylation during prostate carcinogenesis

    Directory of Open Access Journals (Sweden)

    Behbahani Turang E

    2012-03-01

    Full Text Available Abstract Background Global histone modifications have been implicated in the progression of various tumour entities. Our study was designed to assess global methylation levels of histone 4 lysine 20 (H4K20me1-3 at different stages of prostate cancer (PCA carcinogenesis. Methods Global H4K20 methylation levels were evaluated using a tissue microarray in patients with clinically localized PCA (n = 113, non-malignant prostate disease (n = 27, metastatic hormone-naive PCA (mPCA, n = 30 and castration-resistant PCA (CRPC, n = 34. Immunohistochemistry was performed to assess global levels of H4K20 methylation levels. Results Similar proportions of the normal, PCA, and mPCA prostate tissues showed strong H4K20me3 staining. CRPC tissue analysis showed the weakest immunostaining levels of H4K20me1 and H4K20me2, compared to other prostate tissues. H4K20me2 methylation levels indicated significant differences in examined tissues except for normal prostate versus PCA tissue. H4K20me1 differentiates CRPC from other prostate tissues. H4K20me1 was significantly correlated with lymph node metastases, and H4K20me2 showed a significant correlation with the Gleason score. However, H4K20 methylation levels failed to predict PSA recurrence after radical prostatectomy. Conclusions H4K20 methylation levels constitute valuable markers for the dynamic process of prostate cancer carcinogenesis.

  13. B cell depletion inhibits spontaneous autoimmune thyroiditis in NOD.H-2h4 mice.

    Science.gov (United States)

    Yu, Shiguang; Dunn, Robert; Kehry, Marilyn R; Braley-Mullen, Helen

    2008-06-01

    B cells are important for the development of most autoimmune diseases. B cell depletion immunotherapy has emerged as an effective treatment for several human autoimmune diseases, although it is unclear whether B cells are necessary for disease induction, autoantibody production, or disease progression. To address the role of B cells in a murine model of spontaneous autoimmune thyroiditis (SAT), B cells were depleted from adult NOD.H-2h4 mice using anti-mouse CD20 mAb. Anti-CD20 depleted most B cells in peripheral blood and cervical lymph nodes and 50-80% of splenic B cells. Flow cytometry analysis showed that marginal zone B cells in the spleen were relatively resistant to depletion by anti-CD20, whereas most follicular and transitional (T2) B cells were depleted after anti-CD20 treatment. When anti-CD20 was administered before development of SAT, development of SAT and anti-mouse thyroglobulin autoantibody responses were reduced. Anti-CD20 also reduced SAT severity and inhibited further increases in anti-mouse thyroglobulin autoantibodies when administered to mice that already had autoantibodies and thyroid inflammation. The results suggest that B cells are necessary for initiation as well as progression or maintenance of SAT in NOD.H-2h4 mice.

  14. Pleiotropic effect of histamine H4 receptor modulation in the central nervous system

    OpenAIRE

    Nicoletta Galeotti; Maria Domenica Sanna; Carla Ghelardini

    2013-01-01

    The histamine H4 receptor (H4R) is expressed primarily on cells involved in inflammation and immune responses. Recently, it has been reported the functional expression of H4R within neurons of the central nervous system, but their role has been poorly understood. The present study aimed to elucidate the physiopathological role of cerebral H4R in animal models by the intracerebroventricular administration of the H4R agonist VUF 8430 (20e40 mg per mouse). Selectivity of results was ...

  15. Dual-resolution modeling demonstrates greater conformational heterogeneity of CENP-A/H4 dimer than that of H3/H4

    Science.gov (United States)

    Zhao, Haiqing

    Centromere protein A (CENP-A) is a centromere-specific H3 histone variant and shares only about 50% amino acid sequence identity with the canonical H3 protein. CENP-A is required for packaging the centromere and for the proper separation of chromosomes during mitosis. Despite their discrete functions, previously reported crystal structures of the CENP-A/H4 and H3/H4 dimers reveal surprising similarity. In this work, we characterize the structure and dynamics of CENP-A/H4 and H3/H4 dimers with a dual-resolution approach, using both all-atom and coarse-grained (CG) molecular dynamics (MD) simulations. Interestingly, the histone dimer containing CENP-A is more structurally variable than the canonical H3 dimer. Furthermore, our calculations revealed significant conformational distinctions between the interface profiles of CENP-A/H4 and H3/H4. In addition, the presence of the CENP-A-specific chaperone HJURP dramatically reduced the conformational heterogeneity of CENP-A/H4. Overall, these results are in general agreement with the available experimental data and provide new dynamic insights into the mechanisms underpinning the chaperone-mediated assembly of CENP-A nucleosomes in vivo.

  16. Spatial Positioning of RET and H4 Following Radiation Exposure Leads to Tumor Development

    Directory of Open Access Journals (Sweden)

    Yuri E. Nikiforov

    2001-01-01

    Full Text Available Exposure to ionizing radiation is a well-known risk factor for a number of human cancers, including leukemia, thyroid cancer, soft tissue sarcomas, and many others. Although it has been known for a long time that radiation exposure to the cell results in extensive DNA damage, including double strand DNA breaks, the exact mechanisms of radiation-induced carcinogenesis remain unknown. Recently, a large increase in incidence of thyroid cancer was observed in children exposed to radiation after the Chernobyl nuclear accident [1]. A high prevalence of chromosomal rearrangements involving the RET gene was found among these radiation-induced thyroid tumors [2,3]. As a result of such rearrangement, a portion of the RET gene is fused with another gene, typically with the H4 or ELE1. However, since the DNA targets of ionizing radiation are randomly distributed throughout the cell nucleus, the reason for predilection for the RET rearrangements in thyroid cells was unclear.

  17. The Program for Processing Newly-synthesized Histones H3.1 and H4

    Science.gov (United States)

    Campos, Eric I.; Fillingham, Jeffrey; Li, Guohong; Zheng, Haiyan; Voigt, Philipp; Kuo, Wei-Hung W.; Seepany, Harshika; Gao, Zhonghua; Day, Loren A.; Greenblatt, Jack F.

    2010-01-01

    The mechanism by which newly synthesized histones are imported into the nucleus and deposited onto replicating chromatin alongside segregating nucleosomal counterparts is poorly understood, yet this program is expected to bear on the putative epigenetic nature of histone posttranslational modifications. In order to define the events by which naïve pre-deposition histones are imported into the nucleus, we biochemically purified and characterized the gamut of histone H3.1-containing complexes from human cytoplasmic fractions and identified their associated histone PTMs. Through reconstitution assays, biophysical analyses, and live cell manipulations, we describe in detail this series of events, namely the assembly of H3-H4 dimers, the acetylation of histones by the HAT1 holoenzyme, and the transfer of histones between chaperones that culminates with their karyopherin-mediated nuclear import. We further demonstrate the high degree of conservation for this pathway between higher and lower eukaryotes. PMID:20953179

  18. N-alpha-terminal acetylation of histone H4 regulates arginine methylation and ribosomal DNA silencing.

    Directory of Open Access Journals (Sweden)

    Vassia Schiza

    Full Text Available Post-translational modifications of histones play a key role in DNA-based processes, like transcription, by modulating chromatin structure. N-terminal acetylation is unique among the numerous histone modifications because it is deposited on the N-alpha amino group of the first residue instead of the side-chain of amino acids. The function of this modification and its interplay with other internal histone marks has not been previously addressed. Here, we identified N-terminal acetylation of H4 (N-acH4 as a novel regulator of arginine methylation and chromatin silencing in Saccharomyces cerevisiae. Lack of the H4 N-alpha acetyltransferase (Nat4 activity results specifically in increased deposition of asymmetric dimethylation of histone H4 arginine 3 (H4R3me2a and in enhanced ribosomal-DNA silencing. Consistent with this, H4 N-terminal acetylation impairs the activity of the Hmt1 methyltransferase towards H4R3 in vitro. Furthermore, combinatorial loss of N-acH4 with internal histone acetylation at lysines 5, 8 and 12 has a synergistic induction of H4R3me2a deposition and rDNA silencing that leads to a severe growth defect. This defect is completely rescued by mutating arginine 3 to lysine (H4R3K, suggesting that abnormal deposition of a single histone modification, H4R3me2a, can impact on cell growth. Notably, the cross-talk between N-acH4 and H4R3me2a, which regulates rDNA silencing, is induced under calorie restriction conditions. Collectively, these findings unveil a molecular and biological function for H4 N-terminal acetylation, identify its interplay with internal histone modifications, and provide general mechanistic implications for N-alpha-terminal acetylation, one of the most common protein modifications in eukaryotes.

  19. Cloning and Analysis of H4A and H4B Genes from the Macronucleus of Euplotes octocarinatus%八肋游仆虫大核基因组中组蛋白基因H4A和H4B的克隆及分析

    Institute of Scientific and Technical Information of China (English)

    杨旭霞; 许静; 梁爱华; 王伟

    2012-01-01

    组蛋白作为核小体的基本组分,是染色质的结构和功能必需的.组蛋白的变体和修饰共同参与染色质修饰及基因的表达调控.真核生物细胞中的5种组蛋白在进化中高度保守,然而纤毛虫的组蛋白H4与其他真核生物相比有较大的差异.本实验应用PCR技术从八肋游仆虫(Euplotes octocarinatus)中获得了2种组蛋白H4基因,分别为H4A和H4B,GenBank登录号为:JN715068和JN715069.序列分析表明,H4A基因开放阅读框324 bp,预测编码107个氨基酸,分子量为11.6 ku,等电点为10.99.而H4B基因编码框384 bp,编码127个氨基酸,分子量为14.4 ku,等电点为9.93.Blast结果显示,H4A序列与其他生物中H4的一致性相对较高,达81% ~94%,而H4B的一致性为36%~70%.H4A和H4B的一致性仅为44.7%.实时荧光定量PCR表明,H4A的转录本高于H4B.结果提示:在进化过程中八肋游仆虫可能进化出特殊的组蛋白H4基因,不同的组蛋白H4可能发挥不同的功能.%Histones are basic components of nucleosome and essential to chromatin structure and function. Histone posttranslational modifications and sequence variants jointly participate in modification of chromatin and regulation of gene expression. Histones are highly conserved proteins in different organisms. However, a high degree of variation was found in ciliate. In the study, H4 A and HAB were cloned from Euplotes octocarinatus by PCR.GenBank accession number; JN715068 and JN715069. Sequences analysis showed that opening reading frame of the H4A gene was 324 bp, which encoded a 107 amino acid polypeptide with a predicted molecular mass of 11. 6 ku and isoelectric point of 10. 99. The opening reading frame of the H4B gene was 384 bp, which encoded a 127 amino acid polypeptide with a predicted molecular mass of 14. 4 ku and isoelectric point of 9. 93. H4 A gene shared a high identity of 81% -94% with reported HA gene, while H4B shared an identity of 36% -70% with H4 gene from other

  20. A unique binding mode enables MCM2 to chaperone histones H3-H4 at replication forks.

    Science.gov (United States)

    Huang, Hongda; Strømme, Caroline B; Saredi, Giulia; Hödl, Martina; Strandsby, Anne; González-Aguilera, Cristina; Chen, Shoudeng; Groth, Anja; Patel, Dinshaw J

    2015-08-01

    During DNA replication, chromatin is reassembled by recycling of modified old histones and deposition of new ones. How histone dynamics integrates with DNA replication to maintain genome and epigenome information remains unclear. Here, we reveal how human MCM2, part of the replicative helicase, chaperones histones H3-H4. Our first structure shows an H3-H4 tetramer bound by two MCM2 histone-binding domains (HBDs), which hijack interaction sites used by nucleosomal DNA. Our second structure reveals MCM2 and ASF1 cochaperoning an H3-H4 dimer. Mutational analyses show that the MCM2 HBD is required for MCM2-7 histone-chaperone function and normal cell proliferation. Further, we show that MCM2 can chaperone both new and old canonical histones H3-H4 as well as H3.3 and CENPA variants. The unique histone-binding mode of MCM2 thus endows the replicative helicase with ideal properties for recycling histones genome wide during DNA replication.

  1. A unique binding mode enables MCM2 to chaperone histones H3-H4 at replication forks

    DEFF Research Database (Denmark)

    Huang, Hongda; Strømme, Caroline B; Saredi, Giulia

    2015-01-01

    , chaperones histones H3-H4. Our first structure shows an H3-H4 tetramer bound by two MCM2 histone-binding domains (HBDs), which hijack interaction sites used by nucleosomal DNA. Our second structure reveals MCM2 and ASF1 cochaperoning an H3-H4 dimer. Mutational analyses show that the MCM2 HBD is required......During DNA replication, chromatin is reassembled by recycling of modified old histones and deposition of new ones. How histone dynamics integrates with DNA replication to maintain genome and epigenome information remains unclear. Here, we reveal how human MCM2, part of the replicative helicase...... for MCM2-7 histone-chaperone function and normal cell proliferation. Further, we show that MCM2 can chaperone both new and old canonical histones H3-H4 as well as H3.3 and CENPA variants. The unique histone-binding mode of MCM2 thus endows the replicative helicase with ideal properties for recycling...

  2. A unique binding mode enables MCM2 to chaperone histones H3–H4 at replication forks

    Science.gov (United States)

    Huang, Hongda; Strømme, Caroline B; Saredi, Giulia; Hödl, Martina; Strandsby, Anne; González-Aguilera, Cristina; Chen, Shoudeng; Groth, Anja; Patel, Dinshaw J

    2015-01-01

    During DNA replication, chromatin is reassembled by recycling of modified old histones and deposition of new ones. How histone dynamics integrates with DNA replication to maintain genome and epigenome information remains unclear. Here, we reveal how human MCM2, part of the replicative helicase, chaperones histones H3–H4. Our first structure shows an H3–H4 tetramer bound by two MCM2 histone-binding domains (HBDs), which hijack interaction sites used by nucleosomal DNA. Our second structure reveals MCM2 and ASF1 cochaperoning an H3–H4 dimer. Mutational analyses show that the MCM2 HBD is required for MCM2–7 histone-chaperone function and normal cell proliferation. Further, we show that MCM2 can chaperone both new and old canonical histones H3–H4 as well as H3.3 and CENPA variants. The unique histone-binding mode of MCM2 thus endows the replicative helicase with ideal properties for recycling histones genome wide during DNA replication. PMID:26167883

  3. Genome-wide mapping of histone H4 serine-1 phosphorylation during sporulation in Saccharomyces cerevisiae.

    Science.gov (United States)

    Govin, Jérôme; Schug, Jonathan; Krishnamoorthy, Thanuja; Dorsey, Jean; Khochbin, Saadi; Berger, Shelley L

    2010-08-01

    We previously showed that histone H4 serine-1 phosphorylation (H4S1ph) is evolutionarily conserved during gametogenesis, and contributes to post-meiotic nuclear compaction and to full completion of sporulation in the yeast Saccharomyces cerevisiae. Previous studies showed that H4S1ph and another modification of the same histone, H4 acetylation (H4ac), do not occur together and have opposing roles during DNA double-strand break (DSB) repair. In this study, we investigated the relationship between these marks during yeast sporulation. H4S1ph and H4ac co-exist globally during later stages of sporulation, in contrast to DSB repair. Genome-wide mapping during sporulation reveals accumulation of both marks over promoters of genes. Prevention of H4S1ph deposition delays the decline in transcription that normally occurs during spore maturation. Taken together, our results indicate that H4S1ph deposition reinforces reduced transcription that coincides with full spore compaction, without disrupting the local acetylation signature. These studies indicate distinctive features of a histone H4 modification marking system during sporulation compared with DSB repair.

  4. O2CC6H4C6H4CO2(SnPh32∙4H2O AND HO2CC6H4C6H4CO2SnBu2Cl: SYNTHESIS AND INFRARED STUDY

    Directory of Open Access Journals (Sweden)

    ABDOU MBAYE

    2015-02-01

    Full Text Available When the diphenic acid HO2CC6H4C6H4CO2H is allowed to react with SnBu2Cl2 or SnPh3OH, HO2CC6H4C6H4CO2. SnBu2Cl (A and O2CC6H4C6H4CO2(SnPh32∙4H2O(B were obtained and characterized by infrared spectroscopy. The structures are an infinite chain or an oligomer, the diphenic anion being a monodentate or a monochelating ligand. The environment around the tin centers is trigonal bipyramidal or octahedral.

  5. Calculation of thermodynamic, electronic, and optical properties of monoclinic Mg2NiH4

    Energy Technology Data Exchange (ETDEWEB)

    Myers, W.R.; Richardson, T.J.; Rubin, M.D.; Wang, L-W.

    2001-10-01

    Ab initio total-energy density functional theory is used to investigate the low temperature (LT) monoclinic form of Mg2NiH4. The calculated minimum energy geometry of LT Mg2NiH4 is close to that determined from neutron diffraction data, and the NiH4 complex is close to a regular tetrahedron. The enthalpies of the phase change to high temperature (HT) pseudo-cubic Mg2NiH4 and of hydrogen absorption by Mg2Ni are calculated and compared with experimental values. LT Mg2NiH4 is found to be a semiconductor with an indirect band gap of 1.4 eV. The optical dielectric function of LT Mg2NiH4 differs somewhat from that of the HT phase. A calculated thin film transmittance spectrum is consistent with an experimental spectrum.

  6. XAFS Study of the Al K-Edge in NaAlH4

    NARCIS (Netherlands)

    Balde, C.P.; Mijovilovich, A.E.; Koningsberger, D.C.; van der Eerden, A.M.J.; Smith, A.D.; de Jong, K.P.; Bitter, J.H.

    2007-01-01

    Al K-edge (1561.1 eV) XANES and EXAFS spectra of unoxidized NaAlH4, a hydrogen storage material, have been recorded in He atmosphere in a special in situ low-energy cell. The XANES spectrum of NaAlH4 is reported and compared to that of oxidized NaAlH4, thus illustrating the power of XANES spectrosco

  7. Catalytic effect and reaction mechanism of Ti doped in NaAlH4: A review

    Institute of Scientific and Technical Information of China (English)

    WANG Qiang; CHEN YunGui; WU ChaoLing; TAO MingDa

    2008-01-01

    Catalytic effect and hydrogen reaction mechanism of Ti doped in NaAlH4 were elaborated in this paper, and current viewpoints about Ti active species in hydrogen reaction were discussed, in a further step, the possibility and practicality of the hydrogen reaction mechanism of Ti-doped NaAlH4 were elucidated. They could be summarized as follows: while the current theory about the hydrogen reaction mecha-nism of Ti-doped NaAlH4 should be further improved and modified, the research on Ti-doped NaAlH4 would be a recommendable pattern for the catalyst research in other metal complex hydrides.

  8. The histone chaperone Vps75 forms multiple oligomeric assemblies capable of mediating exchange between histone H3-H4 tetramers and Asf1-H3-H4 complexes

    DEFF Research Database (Denmark)

    Hammond, Colin M; Sundaramoorthy, Ramasubramanian; Larance, Mark

    2016-01-01

    Vps75 is a histone chaperone that has been historically characterized as homodimer by X-ray crystallography. In this study, we present a crystal structure containing two related tetrameric forms of Vps75 within the crystal lattice. We show Vps75 associates with histones in multiple oligomers...... catalysed histone H3 K9 acetylation. In the absence of Asf1 this model can be used to generate a complex consisting of a reconfigured Vps75 tetramer bound to a H3-H4 tetramer. This provides a structural explanation for many of the complexes detected biochemically and illustrates the ability of Vps75....... In the presence of equimolar H3-H4 and Vps75, the major species is a reconfigured Vps75 tetramer bound to a histone H3-H4 tetramer. However, in the presence of excess histones, a Vps75 dimer bound to a histone H3-H4 tetramer predominates. We show the Vps75-H3-H4 interaction is compatible with the histone...

  9. Pleiotropic effect of histamine H4 receptor modulation in the central nervous system.

    Science.gov (United States)

    Galeotti, Nicoletta; Sanna, Maria Domenica; Ghelardini, Carla

    2013-08-01

    The histamine H4 receptor (H4R) is expressed primarily on cells involved in inflammation and immune responses. Recently, it has been reported the functional expression of H4R within neurons of the central nervous system, but their role has been poorly understood. The present study aimed to elucidate the physiopathological role of cerebral H4R in animal models by the intracerebroventricular administration of the H4R agonist VUF 8430 (20-40 μg per mouse). Selectivity of results was confirmed by the prevention of the effects produced by the H4R antagonist JNJ 10191584 (3-9 mg/kg p.o.). Neuronal H4R activation induced acute thermal antinociception, indicating that neuronal histamine H4R might be involved in the production of antinociception in the absence of an inflammatory process. An anxiolytic-like effect of intensity comparable to that exerted by diazepam, used as reference drug, was produced in the light-dark box test. VUF 8430 reversed the scopolamine-induced amnesia in the passive avoidance test and showed anorexant activity in food deprived mice. Conversely, the H4R activation did not modify the immobility time in the tail suspension test. Rotarod performance test was employed to demonstrate that the effects observed following the administration of VUF 8430 and JNJ 10191584 were not due to impaired motor function of animals. Furthermore, both compounds did not alter spontaneous mobility and exploratory activity in the hole board test. These results show the antinociceptive, antiamnesic, anxiolytic and anorexant effects induced by neuronal H4R agonism, suggesting that H4 modulators may have broader utility further the control of inflammatory and immune processes.

  10. Virulent bacteriophages can target O104:H4 enteroaggregative Escherichia coli in the mouse intestine.

    Science.gov (United States)

    Maura, Damien; Galtier, Matthieu; Le Bouguénec, Chantal; Debarbieux, Laurent

    2012-12-01

    In vivo bacteriophage targeting of enteroaggregative Escherichia coli (EAEC) was assessed using a mouse intestinal model of colonization with the O104:H4 55989Str strain and a cocktail of three virulent bacteriophages. The colonization model was shown to mimic asymptomatic intestinal carriage found in humans. The addition of the cocktail to drinking water for 24 h strongly decreased ileal and weakly decreased fecal 55989Str concentrations in a dose-dependent manner. These decreases in ileal and fecal bacterial concentrations were only transient, since 55989Str concentrations returned to their original levels 3 days later. These transient decreases were independent of the mouse microbiota, as similar results were obtained with axenic mice. We studied the infectivity of each bacteriophage in the ileal and fecal environments and found that 55989Str bacteria in the mouse ileum were permissive to all three bacteriophages, whereas those in the feces were permissive to only one bacteriophage. Our results provide the first demonstration that bacterial permissivity to infection with virulent bacteriophages is not uniform throughout the gut; this highlights the need for a detailed characterization of the interactions between bacteria and bacteriophages in vivo for the further development of phage therapy targeting intestinal pathogens found in the gut of asymptomatic human carriers.

  11. Ab initio study of Mg(AlH4)2

    NARCIS (Netherlands)

    van Setten, M.J.; de Wijs, G.A.; Popa, V.A.; Popa, V.A.; Brocks, G.

    2005-01-01

    Magnesium alanate Mg(AlH4)2 has recently raised interest as a potential material for hydrogen storage. We apply ab initio calculations to characterize structural, electronic and energetic properties of Mg(AlH4)2. Density functional theory calculations within the generalized gradient approximation

  12. Decomposition of SnH4 molecules on metal and metal-oxide surfaces

    NARCIS (Netherlands)

    Ugur, D.; Storm, A.J.; Verberk, R.; Brouwer, J.C.; Sloof, W.G.

    2014-01-01

    Atomic hydrogen cleaning is a promising method for EUV lithography systems, to recover from surface oxidation and to remove carbon and tin contaminants. Earlier studies showed, however, that tin may redeposit on nearby surfaces due to SnH4 decomposition. This phenomenon of SnH4 decomposition during

  13. Ab initio study of Mg(AlH4)2

    NARCIS (Netherlands)

    Setten, van M.J.; Wijs, de G.A.; Popa, V.A.; Brocks, G.

    2005-01-01

    Magnesium alanate Mg(AlH4)2 has recently raised interest as a potential material for hydrogen storage. We apply ab initio calculations to characterize structural, electronic and energetic properties of Mg(AlH4)2. Density functional theory calculations within the generalized gradient approximation (G

  14. POLYNOMIAL REPRESENTATIONS OF THE AFFINE NAPPI-WITTEN LIE ALGEBRA (H)4

    Institute of Scientific and Technical Information of China (English)

    Chen Xue; Huang Zhili

    2012-01-01

    In this paper,the representation theory for the affine Lie algebra (H)4 associated to the Nappi-Witten Lie algebra H4 is studied.Polynomial representations of the affine Nappi-Witten Lie algebra (H)4 are given.

  15. Study on local mode vibrations of molecular vibrational excitation states in CH4,SiH4 and GeH4 with quasiclassical trajectory method

    Institute of Scientific and Technical Information of China (English)

    杨忠志; 李慎敏; 唐敖庆

    1995-01-01

    By using the quasiclassical trajectory method,changes of normal and local mode vibrationalexcitation energies with time are investigated for XH4 (X=C,Si,Ge) molecules.The results demonstrate thatin a CH4 molecule the coupling between C—H stretching vibration and H—C—H bending vibration is relative-ly large so that the energy transfer is fast;while in SiH4 or GeH4 molecules this coupling is relativelysmall and thus an obvious energy relaxation is observed.This implies that there exists approximate local modevibrations for certain vibrational excitation states.

  16. High deposition rate a-Si:H layers from pure SiH4 and from a 10% dilution of SiH4 in H2

    OpenAIRE

    1999-01-01

    In this paper, we present results of the deposition rates and the characterization of a-Si:H layers deposited from pure SiH4 in a 13.56 MHz Plasma Enhanced Chemical Vapor Deposition (PECVD) equipment, where the use of parallel plates of equal area, long gas residence as well as the optimization of process parameters permitted to double previously reported deposition rates obtained employing this rf frequency and gas. A deposition process using a 10% dilution of SiH4 in H2.was also optimized t...

  17. Fusion Wheat Histone H4 Protein Increases Transfection Efficiency of Non-viral DNA Vector

    Institute of Scientific and Technical Information of China (English)

    WANG Chun-yan; ZHANG Yu-jing

    2011-01-01

    The lack of efficient and non-toxic gene delivery, preferably with non-viral DNA vectors, is generally regarded as a major limitation for gene therapy. In this study, a wheat histone H4 gene was cloned from Triticum aestivum, sequenced, modified and expressed in E. coli. The wheat histone H4 gene and reconstructed H4TL gene encoded wheat histone H4 and a recombinant protein of 141 amino acids with an approximate molecular weight of 15500. Gel electrophoresis mobility shift assays demonstrated that the purified protein had high affinity for DNA.Most significantly, the complex of plasmid pEGFP/Cl with H4TL was transfected with increased efficiency into MCF-7, HO8910, LNCap, A549 and HeLa cells in vitro. These results demonstrate that the targeting of non-viral vectors to tumor-specific receptors provides a cheap, simple and highly efficient tool for gene delivery.

  18. B7-H4 Treatment of T Cells Inhibits ERK, JNK, p38, and AKT Activation.

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    Full Text Available B7-H4 is a newly identified B7 homolog that plays an important role in maintaining T-cell homeostasis by inhibiting T-cell proliferation and lymphokine-secretion. In this study, we investigated the signal transduction pathways inhibited by B7-H4 engagement in mouse T cells. We found that treatment of CD3(+ T cells with a B7-H4.Ig fusion protein inhibits anti-CD3 elicited T-cell receptor (TCR/CD28 signaling events, including phosphorylation of the MAP kinases, ERK, p38, and JNK. B7-H4.Ig treatment also inhibited the phosphorylation of AKT kinase and impaired its kinase activity as assessed by the phosphorylation of its endogenous substrate GSK-3. Expression of IL-2 is also reduced by B7-H4. In contrast, the phosphorylation state of the TCR proximal tyrosine kinases ZAP70 and lymphocyte-specific protein tyrosine kinase (LCK are not affected by B7-H4 ligation. These results indicate that B7-H4 inhibits T-cell proliferation and IL-2 production through interfering with activation of ERK, JNK, and AKT, but not of ZAP70 or LCK.

  19. Defective fullerenes as catalyst for dehydrogenation from NaAlH4 clusters

    Science.gov (United States)

    Agnihotri, Deepak; Meenakshi, Sharma, Hitesh

    2015-06-01

    In the present work we have shown that C60 with defect can act as an effective catalyst for dehydrogenation from NaAlH4 clusters. The investigations have been performed using density functional theory calculations. The NaAlH4 interact weakly with the C60 with vacancy defect with binding energy of 0.26eV. The hydrogen release energy shows sharp decrease in magnitude from 3.82eV in NaAlH4 to 1.97 eV in C59NaAlH4 and 1.63eV in C58BNaAlH4. The results may be explained on the basis of change in the net charge at Na and AlH4 resulting in weaker ionic interaction due to interaction between NaAlH4 cluster and C60 with defect. The present results may provide valued insights of experimental work for exploring the catalytic potential of C60 with various defects.

  20. Enteroaggregative Shiga toxin-producing Escherichia coli of serotype O104:H4 in Belgium and Luxembourg

    Directory of Open Access Journals (Sweden)

    K. De Rauw

    2014-09-01

    Full Text Available In 2011, a large outbreak of infections caused by Shiga toxin-producing Escherichia coli (STEC O104:H4 occurred in Germany. This exceptionally virulent strain combined virulence factors of enteroaggregative E. coli (EAggEC and STEC. After the outbreak only a few sporadic cases of infection with this rare serotype were reported, most of which were related to travel to the Middle East or North Africa. Here we describe two cases of enteroaggregative STEC (Agg-STEC O104:H4 infection that occurred in Belgium in 2012 and 2013 respectively. In both cases travel in a Mediterranean country preceded the infection. The first strain was isolated from the stool of a 42-year-old woman presenting bloody diarrhoea, who had travelled to Tunisia the week before. The second case involves a 14-year-old girl who, upon her return from Turkey to Belgium, suffered from an episode of bloody diarrhoea and haemolytic uraemic syndrome. Extended typing of the isolates with pulsed field gel electrophoresis revealed that the strains were closely related, though not exactly the same as the 2011 outbreak strain. This report supports the previously made hypothesis that Agg-STEC has a human reservoir and might be imported by travellers coming from an area where the pathogen is endemic. Furthermore, it emphasizes the concern that these bacteria may cause future outbreaks as evenly virulent O104:H4 isolates seem to be widespread.

  1. Hemorrhagin VaH4, a covalent heterodimeric P-III metalloproteinase from Vipera ammodytes ammodytes with a potential antitumour activity.

    Science.gov (United States)

    Leonardi, Adrijana; Sajevic, Tamara; Kovačič, Lidija; Pungerčar, Jože; Lang Balija, Maja; Halassy, Beata; Trampuš Bakija, Alenka; Križaj, Igor

    2014-01-01

    In the envenomation caused by a bite of Vipera ammodytes ammodytes, the most venomous snake in Europe, hemorrhage is usually the most severe consequence in man. Identifying and understanding the hemorrhagic components of its venom is therefore particularly important in optimizing medical treatment of patients. We describe a novel high molecular mass hemorrhagin, VaH4. The isolated molecule is a covalent dimer of two homologous subunits, VaH4-A and VaH4-B. Complete structural characterization of A and partial characterization of B revealed that both belong to the P-III class of snake venom metalloproteinases (SVMPs), comprising a metalloproteinase, a disintegrin-like domain and a cysteine-rich domain. However, neither VaH4-A nor VaH4-B possess the Cys174 involved in the inter-subunit disulphide bond of P-III SVMPs. A three-dimensional model of the VaH4 dimer suggests that Cys132 serves this function. This implies that dimers in the P-III class of SVMPs can be formed either between their Cys132 or Cys174 residues. The proteolytic activity and stability of VaH4 depend on Zn²⁺ and Ca²⁺ ions and the presence of glycosaminoglycans, which indicates physiological interaction of VaH4 with the latter element of the extracellular matrix (ECM). The molecular mass of VaH4, determined by MALDI/TOF mass spectrometry, is 110.2 kDa. N-deglycosylation reduced the mass of each monomer by 8.7 kDa. The two possible N-glycosylation sites in VaH4-A are located at completely different positions from those in homodimeric P-IIIc VaH3 from the same venom, however, without any evident functional implications. The hemorrhagic activity of this slightly acidic SVMP is ascribed to its hydrolysis of components of the ECM, particularly fibronectin and nidogen, and of some blood coagulation proteins, in particular the α-chain of fibrinogen. VaH4 is also significant medically as we found it cytotoxic against cancer cells and due to its substantial sequence similarity to ADAM/ADAMTS family of

  2. The cryptomonad histone H4-encoding gene: structure and chromosomal localization.

    Science.gov (United States)

    Müller, S B; Rensing, S A; Maier, U G

    1994-12-15

    Cryptomonads are unicellular flagellates whose plastids are surrounded by four membranes. A periplastidal compartment, containing eukaryote-type ribosomes, starch grains and a so-called nucleomorph, is located between the inner and outer membrane pairs. The nucleomorph has been shown to be the vestigial nucleus of a eukaryotic endosymbiont. In order to obtain more information about the chromatin structure of the nucleomorph and the host nuclear chromosomes, we studied the distribution of the histone, H4. H4 was not detectable in the nucleomorph by immunolocalization, thus supporting earlier findings by Gibbs [In: Wiesner et al. (Eds.), Experimental Phycology 1, 1990, pp. 145-157]. Likewise, no H4 DNA was demonstrable in the nucleomorph by Southern hybridization. Sequence analysis, and Southern and Northern blot data of a cryptomonad gene, H4, indicate an intermediate position for these genes between animals and plants.

  3. Analytic model of nanoparticle formation and growth in a SiH4-Ar plasma

    Science.gov (United States)

    Gordiets, B. F.; Bertran, E.

    2009-05-01

    A kinetic model of formation and growth of nanoparticles in a low-pressure plasma-chemical reactor with an rf capacitive discharge in a SiH4-Ar mixture is presented. Analytic formulas are derived for calculating the concentration of monomers, as well as the concentration and average size of nanoparticles. The results are compared with the results of numerical calculations and experimental data for nanoparticles in a SiH4-Ar plasma.

  4. C2H4 adsorption on Cu(210), revisited: bonding nature and coverage effects.

    Science.gov (United States)

    Amino, Shuichi; Arguelles, Elvis; Agerico Diño, Wilson; Okada, Michio; Kasai, Hideaki

    2016-08-24

    With the aid of density functional theory (DFT)-based calculations, we investigate the adsorption of C2H4 on Cu(210). We found two C2H4 adsorption sites, viz., the top of the step-edge atom (S) and the long bridge between two step-edge atoms (SS) of Cu(210). The step-edge atoms on Cu(210) block the otherwise active terrace sites found on copper surfaces with longer step sizes. This results in the preference for π-bonded over di-σ-bonded C2H4. We also found two stable C2H4 adsorption orientations on the S- and SS-sites, viz., with the C2H4 C[double bond, length as m-dash]C bond parallel (fit) and perpendicular (cross) to [001]. Furthermore, we found that the three peaks observed in previous temperature programmed desorption (TPD) experiment [Surf. Sci., 2011, 605, 934-940] could be attributed to C2H4 in the S-fit or S-cross, S-fit and S-cross-fit (S-cross and S-fit configurations that both exist in the same unit cell) configurations on Cu(210).

  5. TRPV1 and PLC Participate in Histamine H4 Receptor-Induced Itch

    Directory of Open Access Journals (Sweden)

    Tunyu Jian

    2016-01-01

    Full Text Available Histamine H4 receptor has been confirmed to play a role in evoking peripheral pruritus. However, the ionic and intracellular signaling mechanism of activation of H4 receptor on the dorsal root ganglion (DRG neurons is still unknown. By using cell culture and calcium imaging, we studied the underlying mechanism of activation of H4 receptor on the DRG neuron. Immepip dihydrobromide (immepip—a histamine H4 receptor special agonist under cutaneous injection—obviously induced itch behavior of mice. Immepip-induced scratching behavior could be blocked by TRPV1 antagonist AMG9810 and PLC pathway inhibitor U73122. Application of immepip (8.3–50 μM could also induce a dose-dependent increase in intracellular Ca2+ (Ca2+i of DRG neurons. We found that 77.8% of the immepip-sensitized DRG neurons respond to the TRPV1 selective agonist capsaicin. U73122 could inhibit immepip-induced Ca2+ responses. In addition, immepip-induced Ca2+i increase could be blocked by ruthenium red, capsazepine, and AMG9810; however it could not be blocked by TRPA1 antagonist HC-030031. These results indicate that TRPV1 but not TRPA1 is the important ion channel to induce the DRG neurons’ responses in the downstream signaling pathway of histamine H4 receptor and suggest that TRPV1 may be involved in the mechanism of histamine-induced itch response by H4 receptor activation.

  6. The role of histone H4 biotinylation in the structure of nucleosomes.

    Directory of Open Access Journals (Sweden)

    Nina A Filenko

    Full Text Available BACKGROUND: Post-translational modifications of histones play important roles in regulating nucleosome structure and gene transcription. It has been shown that biotinylation of histone H4 at lysine-12 in histone H4 (K12Bio-H4 is associated with repression of a number of genes. We hypothesized that biotinylation modifies the physical structure of nucleosomes, and that biotin-induced conformational changes contribute to gene silencing associated with histone biotinylation. METHODOLOGY/PRINCIPAL FINDINGS: To test this hypothesis we used atomic force microscopy to directly analyze structures of nucleosomes formed with biotin-modified and non-modified H4. The analysis of the AFM images revealed a 13% increase in the length of DNA wrapped around the histone core in nucleosomes with biotinylated H4. This statistically significant (p<0.001 difference between native and biotinylated nucleosomes corresponds to adding approximately 20 bp to the classical 147 bp length of nucleosomal DNA. CONCLUSIONS/SIGNIFICANCE: The increase in nucleosomal DNA length is predicted to stabilize the association of DNA with histones and therefore to prevent nucleosomes from unwrapping. This provides a mechanistic explanation for the gene silencing associated with K12Bio-H4. The proposed single-molecule AFM approach will be instrumental for studying the effects of various epigenetic modifications of nucleosomes, in addition to biotinylation.

  7. Aberrant histone H4 acetylation in dead somatic cell-cloned calves

    Institute of Scientific and Technical Information of China (English)

    Lei Zhang; Shaohua Wang; Qiang Li; Xiangdong Ding; Yunping Dai; Ning Li

    2008-01-01

    In somatic cell-cloned animals, inefficient epigenetic reprogramming can result in an inappropriate gene expression and histone H4 acetylation is one of the key epigenetic modifications regulating gene expression. In this study, we investigated the levels of histone H4 acetylation of 11 development-related genes and expression levels of 19 genes in lungs of three normal control calves and nine aber-rant somatic cell-cloned calves. The results showed that nine studied genes had decreased acetylation levels in aberrant clones (p 0.05). Whereas 13 genes had significantly decreased expression (p 0.05), and only one gene had higher expression level in clones (p < 0.05). Furthermore, FGFR, GHR, HGFR and IGF1 genes showed lowered levels of both histone H4 acetylation and expression in aberrant clones than in controls, and the level of histone H4 acetylation was even more lowered in aberrant clones than those in controls. It was suggested that the lower levels of histone H4 acetylation in aberrant clones caused by the previous memory of cell differentiation might not support enough chromatin reprogramming, thus affecting appropriate gene expressions, and growth and development of the cloned calves. To our knowledge, this is the first study on how histone H4 acetylation affects gene expression in organs of somatic cell-cloned calves.

  8. Keggin-type H4PVMo11O40-based catalysts for the isobutane selective oxidation

    Institute of Scientific and Technical Information of China (English)

    PAUL; Sébastien; SULTAN; Manzoor; BORDES-RICHARD; Elisabeth

    2010-01-01

    Cesium heteropolysalts Cs3PMo12O40 and HCs3PVMo11O40 were synthesized by modifying the preparation conditions in order to get materials with a much higher surface area than the original Keggin-type heteropolyacids(H3PMo12O40 and H4PVMo11O40).These solids were used as carriers for the dispersion of H4PVMo11O40 heteropolyacid by the incipient wetness impregnation technique.The textural and structural properties of supports and catalysts were examined by scanning electron microscopy,N2 adsorption-desorption isotherms and Raman spectroscopy.The supported catalysts were studied before and after red/ox pretreatments by X-ray photoelectron spectroscopy,which showed that both the surface composition and oxidized to reduced species ratio depend on the used carrier.The catalytic performances of these novel supported catalysts in the selective oxidation of isobutane to methacrylic acid and methacrolein were studied.The best catalytic properties were obtained when H4PVMo11O40 was supported on HCs3PVMo11O40.The isobutane conversion and yield of the desired oxygenates increased along the unsupported H4PVMo11O40<H4PVMo11O40/Cs3PMo12O40<H4PVMo11O40/HCs3PVMo11O40 series.

  9. Temperature and pressure dependent rate coefficients for the reaction of C2H4 + HO2 on the C2H4O2H potential energy surface.

    Science.gov (United States)

    Guo, JunJiang; Xu, JiaQi; Li, ZeRong; Tan, NingXin; Li, XiangYuan

    2015-04-02

    The potential energy surface (PES) for reaction C2H4 + HO2 was examined by using the quantum chemical methods. All rates were determined computationally using the CBS-QB3 composite method combined with conventional transition state theory(TST), variational transition-state theory (VTST) and Rice-Ramsberger-Kassel-Marcus/master-equation (RRKM/ME) theory. The geometries optimization and the vibrational frequency analysis of reactants, transition states, and products were performed at the B3LYP/CBSB7 level. The composite CBS-QB3 method was applied for energy calculations. The major product channel of reaction C2H4 + HO2 is the formation C2H4O2H via an OH(···)π complex with 3.7 kcal/mol binding energy which exhibits negative-temperature dependence. We further investigated the reactions related to this complex, which were ignored in previous studies. Thermochemical properties of the species involved in the reactions were determined using the CBS-QB3 method, and enthalpies of formation of species were compared with literature values. The calculated rate constants are in good agreement with those available from literature and given in modified Arrhenius equation form, which are serviceable in combustion modeling of hydrocarbons. Finally, in order to illustrate the effect for low-temperature ignition of our new rate constants, we have implemented them into the existing mechanisms, which can predict ethylene ignition in a shock tube with better performance.

  10. Aggregative adherence fimbriae I (AAF/I) mediate colonization of fresh produce and abiotic surface by Shiga toxigenic enteroaggregative Escherichia coli O104:H4

    Science.gov (United States)

    The Shiga toxigenic Escherichia coli O104:H4 bares the characteristics of both enterohemorrhagic (EHEC) and enteroaggregative (EAEC) E. coli. It produces plasmid encoded aggregative adherence fimbriae I (AAF/I) which mediate cell aggregation and biofilm formation in human intestine and promote Shiga...

  11. Gold complexes with the selenolate ligand [2-(Me2NCH2)C6H4Se]-.

    Science.gov (United States)

    Crespo, Olga; Gimeno, M Concepción; Laguna, Antonio; Kulcsar, Monika; Silvestru, Cristian

    2009-05-04

    The reaction of [2-(Me(2)NCH(2))C(6)H(4)Se]M (M = Li, K) with the gold(phosphine) complexes [AuCl(PR(3))] gives the mononuclear gold-selenolate species [Au{SeC(6)H(4)(CH(2)NMe(2))-2}(PPh(3))] (1) or [Au{SeC(6)H(4)(CH(2)NMe(2))-2}(PPh(2)py)] (2), respectively. The treatment of the [2-(Me(2)NCH(2))C(6)H(4)Se]M with [Au(2)Cl(2)(mu-P-P)] [P-P = bis(diphenylphosphino)methane (dppm), bis(diphenylphosphino)ethane (dppe), 1,1'-bis(diphenylphosphino)ferrocene (dppf)] derivatives gives complexes with stoichiometry [Au(2){SeC(6)H(4)(CH(2)NMe(2))-2}(2)(mu-P-P)] [P-P = dppm (3), dppe (4), or dppf (5)]. These complexes exhibit a different structural framework, that is, 4 crystallizes as a chain polymer with intermolecular aurophilic bonding, while 5 shows an intramolecular Au(I)...Au(I) interaction. The gold(III) derivative Bu(4)N[Au(C(6)F(5))(3){SeC(6)H(4)(CH(2)NMe(2))-2}] (6) is obtained by reaction of [2-(Me(2)NCH(2))C(6)H(4)Se]K and Bu(4)N[AuBr(C(6)F(5))(3)], in a 1:1 molar ratio. These species exhibit luminescence which probably arises from a mixed (3)LMMCT and (3)MC excited state. The emission properties in these complexes seem to be useful for structural predictions and lead to the proposal of intermolecular aggregation in the solid state and frozen solution for complexes 1, 2, 3, whose crystal structures have not been elucidated.

  12. Point mutation of H3/H4 histones affects acetic acid tolerance in Saccharomyces cerevisiae.

    Science.gov (United States)

    Liu, Xiangyong; Zhang, Xiaohua; Zhang, Zhaojie

    2014-10-10

    The molecular mechanism of acetic acid tolerance in yeast remains unclear despite of its importance for efficient cellulosic ethanol production. In this study, we examined the effects of histone H3/H4 point mutations on yeast acetic acid tolerance by comprehensively screening a histone H3/H4 mutant library. A total of 24 histone H3/H4 mutants (six acetic acid resistant and 18 sensitive) were identified. Compared to the wild-type strain, the histone acetic acid-resistant mutants exhibited improved ethanol fermentation performance under acetic acid stress. Genome-wide transcriptome analysis revealed that changes in the gene expression in the acetic acid-resistant mutants H3 K37A and H4 K16Q were mainly related to energy production, antioxidative stress. Our results provide novel insights into yeast acetic acid tolerance on the basis of histone, and suggest a novel approach to improve ethanol production by altering the histone H3/H4 sequences.

  13. Hydrogen Desorption Properties of Bulk and Nanoconfined LiBH4-NaAlH4

    Directory of Open Access Journals (Sweden)

    Payam Javadian

    2016-06-01

    Full Text Available Nanoconfinement of 2LiBH4-NaAlH4 into a mesoporous carbon aerogel scaffold with a pore size, BET surface area and total pore volume of Dmax = 30 nm, SBET = 689 m2/g and Vtot = 1.21 mL/g, respectively is investigated. Nanoconfinement of 2LiBH4-NaAlH4 facilitates a reduction in the temperature of the hydrogen release by 132 °C, compared to that of bulk 2LiBH4-NaAlH4 and the onset of hydrogen release is below 100 °C. The reversible hydrogen storage capacity is also significantly improved for the nanoconfined sample, maintaining 83% of the initial hydrogen content after three cycles compared to 47% for that of the bulk sample. During nanoconfinement, LiBH4 and NaAlH4 reacts to form LiAlH4 and NaBH4 and the final dehydrogenation products, obtained at 481 °C are LiH, LiAl, AlB2 and Al. After rehydrogenation of the nanoconfined sample at T = 400 °C and p(H2 = 126 bar, amorphous NaBH4 is recovered along with unreacted LiH, AlB2 and Al and suggests that NaBH4 is the main compound that can reversibly release and uptake hydrogen.

  14. PRMT5-mediated methylation of histone H4R3 recruits DNMT3A, coupling histone and DNA methylation in gene silencing

    Science.gov (United States)

    Tan, Yuen T; Li, Haitao; Moritz, Robert L; Simpson, Richard J; Cerruti, Loretta; Curtis, David J; Patel, Dinshaw J; Allis, C David; Cunningham, John M; Jane, Stephen M

    2015-01-01

    Mammalian gene silencing is established through methylation of histones and DNA, although the order in which these modifications occur remains contentious. Using the human β-globin locus as a model, we demonstrate that symmetric methylation of histone H4 arginine 3 (H4R3me2s) by the protein arginine methyltransferase PRMT5 is required for subsequent DNA methylation. H4R3me2s serves as a direct binding target for the DNA methyltransferase DNMT3A, which interacts through the ADD domain containing the PHD motif. Loss of the H4R3me2s mark through short hairpin RNA–mediated knockdown of PRMT5 leads to reduced DNMT3A binding, loss of DNA methylation and gene activation. In primary erythroid progenitors from adult bone marrow, H4R3me2s marks the inactive methylated globin genes coincident with localization of PRMT5. Our findings define DNMT3A as both a reader and a writer of repressive epigenetic marks, thereby directly linking histone and DNA methylation in gene silencing. PMID:19234465

  15. Muon Beam Studies in the H4 beam line and the Gamma Irradiation Facility (GIF++)

    CERN Document Server

    Margraf, Rachel; CERN. Geneva. EN Department

    2017-01-01

    In this report, I summarize my work of detailed study and optimization of the muon beam configuration of H4 beam line in SPS North Area. Using Monte-Carlo simulations, I studied the properties and behavior of the muon beam in combination with the field of the large, spectrometer “ GOLIATH” magnet at -1.5, -1.0, 0, 1.0 and 1.5 Tesla, which is shown to affect the central x position of the muon beam that is delivered to the Gamma Irradiation Facility (GIF++). I also studied the muon beam for different configurations of the two XTDV beam dumps upstream of GIF++ in the H4 beam line. I will also discuss my role in mapping the magnetic field of the GOLIATH magnet in the H4 beam line.

  16. Relationship between lunasin's sequence and its inhibitory activity of histones H3 and H4 acetylation.

    Science.gov (United States)

    Hernández-Ledesma, Blanca; Hsieh, Chia-Chien; de Lumen, Ben O

    2011-07-01

    Dysfunction of histone acetyltransferases (HATs) or histone deacetylases (HDACs) involved in histones acetylation has been associated with cancer. Inhibitors of these enzymes are becoming potential targets for new therapies. This study reports by Western-Blot analysis, that peptide lunasin is mainly an in vitro inhibitor of histone H4 acetylation by P300/cAMP-response element-binding protein (CBP)-associated factor (PCAF), with IC₅₀ values dependent on the lysine position sensitive to be acetylated (0.83 μM (H4-Lys 8), 1.27 μM (H4-Lys 12) and 0.40 μM (H4-Lys 5, 8, 12, 16)). Lunasin is also capable of inhibiting H3 acetylation (IC₅₀ of 5.91 μM (H3-Lys 9) and 7.81 μM (H3-Lys 9, 14)). Studies on structure-activity relationship establish that lunasin's sequence are essential for inhibiting H4 acetylation whereas poly-D sequence is the main active sequence responsible for H3 acetylation inhibition. Lunasin also inhibits H3 and H4 acetylation and cell proliferation (IC₅₀ of 181 μM) in breast cancer MDA-MB-231 cells. Moreover, this peptide decreases expression of cyclins and cyclin dependent kinases-4 and -6, implicated in cell cycle pathways. Results from this study demonstrates lunasin's role as modulator of histone acetylation and protein expression that might contribute on its chemopreventive properties against breast cancer. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Differential contributions of histone H3 and H4 residues to heterochromatin structure.

    Science.gov (United States)

    Yu, Qun; Olsen, Lars; Zhang, Xinmin; Boeke, Jef D; Bi, Xin

    2011-06-01

    Transcriptional silencing in Saccharomyces cerevisiae is mediated by heterochromatin. There is a plethora of information regarding the roles of histone residues in transcriptional silencing, but exactly how histone residues contribute to heterochromatin structure is not resolved. We address this question by testing the effects of a series of histone H3 and H4 mutations involving residues in their aminoterminal tails, on the solvent-accessible and lateral surfaces of the nucleosome, and at the interface of the H3/H4 tetramer and H2A/H2B dimer on heterochromatin structure and transcriptional silencing. The general state, stability, and conformational heterogeneity of chromatin are examined with a DNA topology-based assay, and the primary chromatin structure is probed by micrococcal nuclease. We demonstrate that the histone mutations differentially affect heterochromatin. Mutations of lysine 16 of histone H4 (H4-K16) and residues in the LRS (loss of rDNA silencing) domain of nucleosome surface markedly alter heterochromatin structure, supporting the notion that H4-K16 and LRS play key roles in heterochromatin formation. Deletion of the aminoterminal tail of H3 moderately alters heterochromatin structure. Interestingly, a group of mutations in the globular domains of H3 and H4 that abrogate or greatly reduce transcriptional silencing increase the conformational heterogeneity and/or reduce the stability of heterochromatin without affecting its overall structure. Surprisingly, yet another series of mutations abolish or reduce silencing without significantly affecting the structure, stability, or conformational heterogeneity of heterochromatin. Therefore, histone residues may contribute to the structure, stability, conformational heterogeneity, or other yet-to-be-characterized features of heterochromatin important for transcriptional silencing.

  18. [AuHg(o-C6H4PPh22I]: A Dinuclear Heterometallic Blue Emitter

    Directory of Open Access Journals (Sweden)

    José M. López-de-Luzuriaga

    2015-02-01

    Full Text Available The heteronuclear AuI/HgII complex [AuHg(o-C6H4PPh22I] (1 was prepared by reacting of [Hg(2-C6H4PPh22] with [Au(tht2]ClO4 (1:1 and NaI in excess. The heterometallic compound 1 has been structurally characterized and shows an unusual blue luminescent emission in the solid state. Theoretical calculations suggest that that the origin of the emission arises from the iodide ligand arriving at metal-based orbitals in a Ligand to Metal-Metal Charge Transfer transition.

  19. Modeling Inter-Pixel Crosstalk in Teledyne Imaging Sensors H4RG Detectors

    CERN Document Server

    Dudik, R P; Dorland, B N; Veillette, D; Waczynski, A; Lane, B; Loose, M; Kan, E; Waterman, J; Pravdo, S

    2012-01-01

    CMOS-hybrid arrays have recently surfaced as competitive optical detectors for use in ground- and space-based astronomy. One source of error in these detectors that does not appear in more traditional CCD arrays is the inter-pixel capacitance component of crosstalk. In this paper we use a single pixel reset method to model inter-pixel capacitance (IPC). We combine this IPC model with a model for charge diffusion to estimate the total crosstalk on H4RG arrays. Finally, we compare our model results to Fe55 data obtained using an astrometric camera built to test the H4RG-B0 generation detectors.

  20. Ab initio quasiparticle energies in 2H, 4H, and 6H SiC

    Science.gov (United States)

    Ummels, R. T. M.; Bobbert, P. A.; van Haeringen, W.

    1998-09-01

    Ab initio quasiparticle energies are calculated for the 2H, 4H, and 6H polytypes of SiC within the GW approximation for the self-energy. The starting point is a calculation within the pseudopotential local-density approximation framework. The calculated fundamental gaps of 3.15, 3.35, and 3.24 eV for 2H, 4H, and 6H SiC, respectively, show very good agreement with experimental data. The energy dependence of the screened interaction is modeled by a plasmon pole model from which the plasmon band structures are obtained.

  1. Relationship between B7-H4 and diabetes%B7-H4与糖尿病关系的研究进展

    Institute of Scientific and Technical Information of China (English)

    汝燕; 李素梅

    2011-01-01

    Type 1 diabetes mellitus is an autoimmune disease of selective destruction of pancreatic β cell mediated by T cell, while type 2 diabetes mellitus has recognized the existence of a state of chronic low-grade inflammation. Illuminating the mechanisms of immune system activation is enormously significant in the prevention and treatment of diabetes and related metabolic disorder. This article explores the expression of co-stimulating factor B7-H4 and its relationship with the occurrence and development of diabetes mellitus, then find a new way for reasonable diagnosis and treatment of diabetic nephropathy.%1型糖尿病(Type 1 diabetes mellitus,T1DM)是一种T细胞介导的胰岛β细胞选择性破坏的自身免疫病,2型糖尿病( Type 2 diabetes mellitus,T2DM)存在一种慢性的低度炎症状态,阐明免疫系统活化机制对糖尿病(DM)及相关代谢紊乱防治具有十分重要的意义.该文探讨糖尿病患者共刺激因子B7-H4的表达及其与疾病发生发展的关系,并为寻找糖尿病肾病的合理的诊断与治疗提供新的途径.

  2. The BAH domain of ORC1 links H4K20me2 to DNA replication licensing and Meier-Gorlin syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Alex J; Song, Jikui; Cheung, Peggie; Ishibe-Murakami, Satoko; Yamazoe, Sayumi; Chen, James K; Patel, Dinshaw J; Gozani, Or [Stanford; (MSKCC); (Stanford-MED)

    2012-07-11

    The recognition of distinctly modified histones by specialized 'effector' proteins constitutes a key mechanism for transducing molecular events at chromatin to biological outcomes. Effector proteins influence DNA-templated processes, including transcription, DNA recombination and DNA repair; however, no effector functions have yet been identified within the mammalian machinery that regulate DNA replication. Here we show that ORC1 - a component of ORC (origin of replication complex), which mediates pre-DNA replication licensing - contains a bromo adjacent homology (BAH) domain that specifically recognizes histone H4 dimethylated at lysine 20 (H4K20me2). Recognition of H4K20me2 is a property common to BAH domains present within diverse metazoan ORC1 proteins. Structural studies reveal that the specificity of the BAH domain for H4K20me2 is mediated by a dynamic aromatic dimethyl-lysine-binding cage and multiple intermolecular contacts involving the bound peptide. H4K20me2 is enriched at replication origins, and abrogating ORC1 recognition of H4K20me2 in cells impairs ORC1 occupancy at replication origins, ORC chromatin loading and cell-cycle progression. Mutation of the ORC1 BAH domain has been implicated in the aetiology of Meier-Gorlin syndrome (MGS), a form of primordial dwarfism, and ORC1 depletion in zebrafish results in an MGS-like phenotype. We find that wild-type human ORC1, but not ORC1-H4K20me2-binding mutants, rescues the growth retardation of orc1 morphants. Moreover, zebrafish depleted of H4K20me2 have diminished body size, mirroring the phenotype of orc1 morphants. Together, our results identify the BAH domain as a novel methyl-lysine-binding module, thereby establishing the first direct link between histone methylation and the metazoan DNA replication machinery, and defining a pivotal aetiological role for the canonical H4K20me2 mark, via ORC1, in primordial dwarfism.

  3. File list: His.PSC.05.H4K16ac.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.PSC.05.H4K16ac.AllCell mm9 Histone H4K16ac Pluripotent stem cell SRX298193,SRX2...12326,SRX212325,SRX298194 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.PSC.05.H4K16ac.AllCell.bed ...

  4. The structure of (CENP-A-H4)2 reveals physical features that mark centromeres

    Energy Technology Data Exchange (ETDEWEB)

    Sekulic, Nikolina; Bassett, Emily A; Rogers, Danielle J; Black, Ben E [UPENN-MED

    2010-09-20

    Centromeres are specified epigenetically, and the histone H3 variant CENP-A is assembled into the chromatin of all active centromeres. Divergence from H3 raises the possibility that CENP-A generates unique chromatin features to mark physically centromere location. Here we report the crystal structure of a subnucleosomal heterotetramer, human (CENP-A-H4)2, that reveals three distinguishing properties encoded by the residues that comprise the CENP-A targeting domain (CATD; ref. 2): (1) a CENP-A-CENP-A interface that is substantially rotated relative to the H3-H3 interface; (2) a protruding loop L1 of the opposite charge as that on H3; and (3) strong hydrophobic contacts that rigidify the CENP-A-H4 interface. Residues involved in the CENP-A-CENP-A rotation are required for efficient incorporation into centromeric chromatin, indicating specificity for an unconventional nucleosome shape. DNA topological analysis indicates that CENP-A-containing nucleosomes are octameric with conventional left-handed DNA wrapping, in contrast to other recent proposals. Our results indicate that CENP-A marks centromere location by restructuring the nucleosome from within its folded histone core.

  5. Genomic epidemiology of the Escherichia coli O104:H4 outbreaks in Europe, 2011

    DEFF Research Database (Denmark)

    Grad, Yonatan H; Lipsitch, Marc; Feldgarden, Michael

    2012-01-01

    The degree to which molecular epidemiology reveals information about the sources and transmission patterns of an outbreak depends on the resolution of the technology used and the samples studied. Isolates of Escherichia coli O104:H4 from the outbreak centered in Germany in May-July 2011, and the ...

  6. Histone H4 deacetylation plays a critical role in early gene silencing during neuronal apoptosis

    Directory of Open Access Journals (Sweden)

    Schlamp Cassandra L

    2010-05-01

    Full Text Available Abstract Background Silencing of normal gene expression occurs early in the apoptosis of neurons, well before the cell is committed to the death pathway, and has been extensively characterized in injured retinal ganglion cells. The causative mechanism of this widespread change in gene expression is unknown. We investigated whether an epigenetic change in active chromatin, specifically histone H4 deacetylation, was an underlying mechanism of gene silencing in apoptotic retinal ganglion cells (RGCs following an acute injury to the optic nerve. Results Histone deacetylase 3 (HDAC3 translocates to the nuclei of dying cells shortly after lesion of the optic nerve and is associated with an increase in nuclear HDAC activity and widespread histone deacetylation. H4 in promoters of representative genes was rapidly and indiscriminately deacetylated, regardless of the gene examined. As apoptosis progressed, H4 of silenced genes remained deacetylated, while H4 of newly activated genes regained, or even increased, its acetylated state. Inhibition of retinal HDAC activity with trichostatin A (TSA was able to both preserve the expression of a representative RGC-specific gene and attenuate cell loss in response to optic nerve damage. Conclusions These data indicate that histone deacetylation plays a central role in transcriptional dysregulation in dying RGCs. The data also suggests that HDAC3, in particular, may feature heavily in apoptotic gene silencing.

  7. Reductive Deoxygenation of Carbonyl to Methylene by LiAlH4/InBr3

    Institute of Scientific and Technical Information of China (English)

    Nan Yan FU; Xue Mei ZHAO; Yao Feng YUAN; Ji Tao WANG

    2003-01-01

    The reductive deoxygenation of aldehydes and ketones into the corresponding alkanes isaccomplished by LiA1H4 in the presence of Lewis acid InBr3. It provides a convenient method tocomplete the transformation from carbonyl compounds to alkanes.

  8. Structural studies of disordered Mg2NiH4 formed by mechanical grinding

    DEFF Research Database (Denmark)

    Rönnebro, Ewa; Jensen, Jens Oluf; Noréus, Dag;

    1999-01-01

    The low temperature phase of Mg2NiH4 was mechanically ground in argon atmosphere. The ordered monoclinic structure was destroyed to form the disordered cubic structure, previously only found above 510 K. With a Guinier-Hagg X-ray camera the cell parameter was determined to be a=6.492(3) Angstrom....

  9. Reactivity enhancement of oxide skins in reversible Ti-doped NaAlH4

    Directory of Open Access Journals (Sweden)

    Renaud Delmelle

    2014-12-01

    Full Text Available The reversibility of hydrogen sorption in complex hydrides has only been shown unambiguously for NaAlH4 doped with transition metal compounds. Despite a multitude of investigations of the effect of the added catalyst on the hydrogen sorption kinetics of NaAlH4, the mechanism of catalysis remains elusive so far. Following the decomposition of TiCl3-doped NaAlH4 by in-situ X-ray photoelectron spectroscopy (XPS, we link the chemical state of the dopant with those of the hydride and decomposition products. Titanium and aluminium change their oxidation states during cycling. The change of the formal oxidation state of Al from III to zero is partly due to the chemical reaction from NaAlH4 to Al. Furthermore, aluminium oxide is formed (Al2O3, which coexists with titanium oxide (Ti2O3. The interplay of metallic and oxidized Ti with the oxide skin might explain the effectiveness of Ti and similar dopants (Ce, Zr….

  10. Interface effects in NaAlH4-carbon nanocomposites for hydrogen storage

    NARCIS (Netherlands)

    Gao, Jinbao|info:eu-repo/dai/nl/315029633; Ngene, Peter|info:eu-repo/dai/nl/314121684; Herrich, Monika; Xia, Wei; Gutfleisch, Oliver; Muhler, Martin; De Jong, Krijn P.|info:eu-repo/dai/nl/06885580X; De Jongh, Petra E.|info:eu-repo/dai/nl/186125372

    2014-01-01

    For practical solid-state hydrogen storage, reversibility under mild conditions is crucial. Complex metal hydrides such as NaAlH4 and LiBH4 have attractive hydrogen contents. However, hydrogen release and especially uptake after desorption are sluggish and require high temperatures and pressures.

  11. Destabilized LiBH4-NaAlH4 Mixtures Doped with Titanium Based Catalysts

    DEFF Research Database (Denmark)

    Shi, Qing; Yu, Xuebin; Feidenhans'l, Robert

    2008-01-01

    in a 1 bar helium atmosphere. A slow hydrogen release is also observed at room temperature in the freshly ball-milled powders due to decomposition of the formed LiAlH4. X-ray powder diffraction spectra shows that the first dehydrogenation step is completed after a couple of days at room temperature. Li...

  12. B7-H4 Pathway in Islet Transplantation and β-Cell Replacement Therapies

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    2011-01-01

    Full Text Available Type 1 diabetes (T1D is a chronic autoimmune disease and characterized by absolute insulin deficiency. β-cell replacement by islet cell transplantation has been established as a feasible treatment option for T1D. The two main obstacles after islet transplantation are alloreactive T-cell-mediated graft rejection and recurrence of autoimmune diabetes mellitus in recipients. T cells play a central role in determining the outcome of both autoimmune responses and allograft survival. B7-H4, a newly identified B7 homolog, plays a key role in maintaining T-cell homeostasis by reducing T-cell proliferation and cytokine production. The relationship between B7-H4 and allograft survival/autoimmunity has been investigated recently in both islet transplantation and the nonobese diabetic (NOD mouse models. B7-H4 protects allograft survival and generates donor-specific tolerance. It also prevents the development of autoimmune diabetes. More importantly, B7-H4 plays an indispensable role in alloimmunity in the absence of the classic CD28/CTLA-4 : B7 pathway, suggesting a synergistic/additive effect with other agents such as CTLA-4 on inhibition of unwanted immune responses.

  13. The potential energy curves for the two structures of H4

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two potential energy curves for the tetrahedron structure and the centered equilateral triangle structure of the H4 system are calculate d by a simple method. The results of the calculation show that the tetrahedron s tructure is more stable than the centered equilateral triangle structure.

  14. B7-H4 as a Target for Breast Cancer Immunotherapy

    Science.gov (United States)

    2013-06-01

    Cell Research 306, 128-141 (2005). [8] G.L. Sica , I.H. Choi, G. Zhu et al. B7-H4, a molecule of the B7 family, negatively regulates T cell immunity...proliferation through translocating into nucleus. Oncogene (2013). [Epub ahead of print] [11] I.H. Choi, G. Zhu, G.L. Sica et al. Genomic

  15. Dynamics of DNA methylation and Histone H4 acetylation during floral bud differentiation in azalea

    Directory of Open Access Journals (Sweden)

    Valledor Luis

    2010-01-01

    Full Text Available Abstract Background The ability to control the timing of flowering is a key strategy for planning production in ornamental species such as azalea, however it requires a thorough understanding of floral transition. Floral transition is achieved through a complex genetic network and regulated by multiple environmental and endogenous cues. Dynamic changes between chromatin states facilitating or inhibiting DNA transcription regulate the expression of floral induction pathways in response to environmental and developmental signals. DNA methylation and histone modifications are involved in controlling the functional state of chromatin and gene expression. Results The results of this work indicate that epigenetic mechanisms such as DNA methylation and histone H4 acetylation have opposite and particular dynamics during the transition from vegetative to reproductive development in the apical shoots of azalea. Global levels of DNA methylation and histone H4 acetylation as well as immunodetection of 5-mdC and acetylated H4, in addition to a morphological study have permitted the delimitation of four basic phases in the development of the azalea bud and allowed the identification of a stage of epigenetic reprogramming which showed a sharp decrease of whole DNA methylation similar to that is defined in other developmental processes in plants and in mammals. Conclusion The epigenetic control and reorganization of chromatin seem to be decisive for coordinating floral development in azalea. DNA methylation and H4 deacetylation act simultaneously and co-ordinately, restructuring the chromatin and regulating the gene expression during soot apical meristem development and floral differentiation.

  16. Synchrotron X-ray studies of Ti-doped NaAlH4.

    Science.gov (United States)

    Canton, Patrizia; Fichtner, Maximilian; Frommen, Christoph; Léon, Aline

    2006-02-23

    Pure and doped NaAlH(4) with 5 mol % Ti on the basis of Ti(13).6THF have been investigated by means of X-ray synchrotron radiation. The Rietveld method has been used to study the possible substitution of Ti inside the NaAlH(4) structure and/or the presence of vacancies. This study indicates that there is no significant variation of the lattice parameter once the Na Alanate is doped with the Ti cluster. From the refinement of the site occupation factors, the substitution of Ti on the Na site can be excluded. A slight improvement was found when Ti was substituted on the Al site, but it is not significant enough to say that Ti definitely substitutes for Al in the Alanate phase. Additionally, there is no evidence for vacancy formation in Ti-colloid-doped sodium Alanate.

  17. Spread of avian pathogenic Escherichia coli ST117 O78:H4 in Nordic broiler production

    DEFF Research Database (Denmark)

    Ronco, Troels; Stegger, Marc; Olsen, Rikke Heidemann

    2017-01-01

    and have in general been characterized as being a genetically diverse population. In the Nordic countries, poultry farmers depend on import of Swedish broiler breeders which are part of a breeding pyramid. During 2014 to 2016, an increased occurrence of colibacillosis on Nordic broiler chicken farms...... nucleotide polymorphisms. In general, the characterized poultry isolates constituted a genetically diverse population. However, the phylogenetic analyses revealed a major clade of 47 closely related ST117 O78:H4 isolates. The isolates in this clade were collected from broiler chickens and breeders...... diseased broilers and breeders. The data indicate that the closely related ST117 O78:H4 strains have been transferred vertically through the broiler breeding pyramid into distantly located farms across the Nordic countries....

  18. High Density Hydrogen Storage System Demonstration Using NaAlH4 Based Complex Compound Hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Daniel A. Mosher; Xia Tang; Ronald J. Brown; Sarah Arsenault; Salvatore Saitta; Bruce L. Laube; Robert H. Dold; Donald L. Anton

    2007-07-27

    This final report describes the motivations, activities and results of the hydrogen storage independent project "High Density Hydrogen Storage System Demonstration Using NaAlH4 Based Complex Compound Hydrides" performed by the United Technologies Research Center under the Department of Energy Hydrogen Program, contract # DE-FC36-02AL67610. The objectives of the project were to identify and address the key systems technologies associated with applying complex hydride materials, particularly ones which differ from those for conventional metal hydride based storage. This involved the design, fabrication and testing of two prototype systems based on the hydrogen storage material NaAlH4. Safety testing, catalysis studies, heat exchanger optimization, reaction kinetics modeling, thermochemical finite element analysis, powder densification development and material neutralization were elements included in the effort.

  19. Novel Structural Motifs in Low Energy Phases of LiAlH4

    Science.gov (United States)

    Amsler, Maximilian; Flores-Livas, José A.; Huan, Tran Doan; Botti, Silvana; Marques, Miguel A. L.; Goedecker, Stefan

    2012-05-01

    We identify a class of novel low energy phases of the hydrogen storage material LiAlH4 by using the ab initio minima hopping crystal structure prediction method. These phases are, unlike previous predictions and known structures of similar materials, characterized by polymeric networks consisting of Al atoms interlinked with H atoms. The most stable structure is a layered ionic crystal with P21/c symmetry, and it has lower free energy than the previously reported structure over a wide range of temperatures. Furthermore, we carry out x-ray diffraction, phonon, and GW band-structure analysis in order to characterize this phase. Its experimental synthesis would have profound implications for the study of dehydrogenation and rehydrogenation processes and the stability problem of LiAlH4 for hydrogen storage applications.

  20. The Abundance of C2H4 in the Circumstellar Envelope of IRC+10216

    Science.gov (United States)

    Fonfría, J. P.; Hinkle, K. H.; Cernicharo, J.; Richter, M. J.; Agúndez, M.; Wallace, L.

    2017-02-01

    High spectral resolution mid-IR observations of ethylene ({{{C}}}2{{{H}}}4) toward the AGB star IRC+10216 were obtained using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF). 80 ro-vibrational lines from the 10.5 μm vibrational mode {ν }7 with J ≲ 30 were detected in absorption. The observed lines are divided into two groups with rotational temperatures of 105 and 400 K (warm and hot lines). The warm lines peak at ≃ ‑14 km s‑1 with respect to the systemic velocity, suggesting that they are mostly formed outwards from ≃ 20{R}\\star . The hot lines are centered at ‑10 km s‑1 indicating that they come from a shell between 10 and 20{\\text{}}{R}\\star . 35% of the observed lines are unblended and can be fitted with a code developed to model the emission of a spherically symmetric circumstellar envelope. The analysis of several scenarios reveals that the {{{C}}}2{{{H}}}4 abundance relative to H2 in the range 5‑20R⋆ is 6.9× {10}-8 on average and it could be as high as 1.1 × 10‑7. Beyond 20{\\text{}}{R}\\star , it is 8.2 × 10‑8. The total column density is (6.5 ± 3.0) × 1015 cm‑2. {{{C}}}2{{{H}}}4 is found to be rotationally under local thermodynamical equilibrium (LTE) and vibrationally out of LTE. One of the scenarios that best reproduce the observations suggests that up to 25% of the {{{C}}}2{{{H}}}4 molecules at 20{\\text{}}{R}\\star could condense onto dust grains. This possible depletion would not significantly influence the gas acceleration although it could play a role in the surface chemistry on the dust grains.

  1. The Abundance of C2H4 in the Circumstellar Envelope of IRC+10216

    Science.gov (United States)

    Fonfría, J. P.; Hinkle, K. H.; Cernicharo, J.; Richter, M. J.; Agúndez, M.

    2017-01-01

    High spectral resolution mid-IR observations of ethylene (C2H4) towards the AGB star IRC+10216 were obtained using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF). Eighty ro-vibrational lines from the 10.5 µm vibrational mode ν7 with J ≲ 30 were detected in absorption. The observed lines are divided into two groups with rotational temperatures of 105 and 400 K (warm and hot lines). The warm lines peak at ≃ −14 km s−1 with respect to the systemic velocity, suggesting that they are mostly formed outwards from ≃ 20R⋆. The hot lines are centered at −10 km s−1 indicating that they come from a shell between 10 and 20R⋆. 35% of the observed lines are unblended and can be fitted with a code developed to model the emission of a spherically symmetric circumstellar envelope. The analysis of several scenarios reveal that the C2H4 abundance relative to H2 in the range 5 − 20R⋆ is 6.9 × 10−8 in average and it could be as high as 1.1 × 10−7. Beyond 20R⋆, it is 8.2 × 10−8. The total column density is (6.5 ± 3.0) × 1015 cm−2. C2H4 is found to be rotationally under local thermodynamical equilibrium (LTE) and vibrationally out of LTE. One of the scenarios that best reproduce the observations suggests that up to 25% of the C2H4 molecules at 20R⋆ could condense onto dust grains. This possible depletion would not influence significantly the gas acceleration although it could play a role in the surface chemistry on the dust grains. PMID:28184097

  2. Spread of avian pathogenic Escherichia coli ST117 O78:H4 in Nordic broiler production

    DEFF Research Database (Denmark)

    Ronco, Troels; Stegger, Marc; Olsen, Rikke Heidemann

    2017-01-01

    Escherichia coli infections known as colibacillosis constitute a considerable challenge to poultry farmers worldwide, in terms of decreased animal welfare and production economy. Colibacillosis is caused by avian pathogenic E. coli (APEC). APEC strains are extraintestinal pathogenic E. coli and h...... diseased broilers and breeders. The data indicate that the closely related ST117 O78:H4 strains have been transferred vertically through the broiler breeding pyramid into distantly located farms across the Nordic countries....

  3. Detection of Interstellar Ethylene Oxide (c-C2H4O)

    Science.gov (United States)

    Dickens, J. E.; Irvine, W. M.; Ohishi, M.; Ikeda, M.; Ishikawa, S.; Nummelin, A.; Hjalmarson, Å.

    1997-11-01

    We report the identification of 10 transitions that support the detection of the small cyclic molecule ethylene oxide (c-C2H4O) in Sgr B2N. Although one of these transitions is severely blended, so that an accurate intensity and line width could not be determined, and two other lines are only marginally detected, we have done Gaussian fits to the remaining seven lines and have performed a rotation diagram analysis. Our results indicate a rotation temperature Trot = 18 K and a molecular column density N(c-C2H4O) = 3.3 × 1014 cm-2, corresponding to a fractional abundance relative to molecular hydrogen of order 6 × 10-11. This is a factor of more than 200 higher than the abundance for this molecule suggested by the ``new standard'' chemistry model of Lee, Bettens, & Herbst. This result suggests that grain chemistry might play an effective role in the production of c-C2H4O. No transitions of this molecule were detected in either Sgr B2M or Sgr B2NW.

  4. Mechanism and kinetics of the reaction NO3 + C2H4.

    Science.gov (United States)

    Nguyen, Thanh Lam; Park, Jaehee; Lee, Kyungjun; Song, Kihyung; Barker, John R

    2011-05-19

    The reaction of NO(3) radical with C(2)H(4) was characterized using the B3LYP, MP2, B97-1, CCSD(T), and CBS-QB3 methods in combination with various basis sets, followed by statistical kinetic analyses and direct dynamics trajectory calculations to predict product distributions and thermal rate constants. The results show that the first step of the reaction is electrophilic addition of an O atom from NO(3) to an olefinic C atom from C(2)H(4) to form an open-chain adduct. A concerted addition reaction mechanism forming a five-membered ring intermediate was investigated, but is not supported by the highly accurate CCSD(T) level of theory. Master-equation calculations for tropospheric conditions predict that the collisionally stabilized NO(3)-C(2)H(4) free-radical adduct constitutes 80-90% of the reaction yield and the remaining products consist mostly of NO(2) and oxirane; the other products are produced in very minor yields. By empirically reducing the barrier height for the initial addition step by 1 kcal mol(-1) from that predicted at the CBS-QB3 level of theory and treating the torsional modes explicitly as one-dimensional hindered internal rotations (instead of harmonic oscillators), the computed thermal rate constants (including quantum tunneling) can be brought into very good agreement with the experimental data for the overall reaction rate constant.

  5. Experimental Results of NWCF Run H4 Calcine Dissolution Studies Performed in FY-98 and -99

    Energy Technology Data Exchange (ETDEWEB)

    Garn, Troy Gerry; Herbst, Ronald Scott; Batcheller, Thomas Aquinas; Sierra, Tracy Laureena

    2001-08-01

    Dissolution experiments were performed on actual samples of NWCF Run H-4 radioactive calcine in fiscal years 1998 and 1999. Run H-4 is an aluminum/sodium blend calcine. Typical dissolution data indicates that between 90-95 wt% of H-4 calcine can be dissolved using 1gram of calcine per 10 mLs of 5-8M nitric acid at boiling temperature. Two liquid raffinate solutions composed of a WM-188/aluminum nitrate blend and a WM-185/aluminum nitrate blend were converted into calcine at the NWCF. Calcine made from each blend was collected and transferred to RAL for dissolution studies. The WM-188/aluminum nitrate blend calcine was dissolved with resultant solutions used as feed material for separation treatment experimentation. The WM-185/aluminum nitrate blend calcine dissolution testing was performed to determine compositional analyses of the dissolved solution and generate UDS for solid/liquid separation experiments. Analytical fusion techniques were then used to determine compositions of the solid calcine and UDS from dissolution. The results from each of these analyses were used to calculate elemental material balances around the dissolution process, validating the experimental data. This report contains all experimental data from dissolution experiments performed using both calcine blends.

  6. Metal-organic frameworks as templates for nanoscale NaAlH4.

    Science.gov (United States)

    Bhakta, Raghunandan K; Herberg, Julie L; Jacobs, Benjamin; Highley, Aaron; Behrens, Richard; Ockwig, Nathan W; Greathouse, Jeffery A; Allendorf, Mark D

    2009-09-23

    Metal-organic frameworks (MOFs) offer an attractive alternative to traditional hard and soft templates for nanocluster synthesis because their ordered crystalline lattice provides a highly controlled and inherently understandable environment. We demonstrate that MOFs are stable hosts for metal hydrides proposed for hydrogen storage and their reactive precursors, providing platform to test recent theoretical predictions that some of these materials can be destabilized with respect to hydrogen desorption by reducing their critical dimension to the nanoscale. With the MOF HKUST-1 as template, we show that NaAlH(4) nanoclusters as small as eight formula units can be synthesized. The confinement of these clusters within the MOF pores dramatically accelerates the desorption kinetics, causing decomposition to occur at approximately 100 degrees C lower than bulk NaAlH(4). However, using simultaneous thermogravimetric modulated beam mass spectrometry, we also show that the thermal decomposition mechanism of NaAlH(4) is complex and may involve processes such as nucleation and growth in addition to the normally assumed two-step chemical decomposition reactions.

  7. Commissioning and Operation of the H4IRRAD Mixed-Field Test Area

    CERN Document Server

    Biskup, B; Calviani, M; Efthymiopoulos, I; Kwee, R; Mekki, J; La Torre, F; Lebbos, E; Mala, P; Manessi, G; Nordt, A; Pozzi, F; Roeed, K; Severino, C; Silari, M; Thornton, A

    2011-01-01

    This note reports on the commissioning and operation period of the H4IRRAD Test Area in which well characterised mixed-fields are provided for LHC equipment users. In benchmark simulations the mixed-field components were estimated and measured with the H4IRRAD beam and radiation monitoring systems. The radiation monitors, the “RadMons” and beam-loss monitors (BLMs) are the same detector types used for monitoring radiation fluences in the underground areas of the LHC. In the first two irradiation periods various equipment was exposed to irradiation produced by a secondary proton beam of 280 GeV impacting on the H4IRRAD copper target. Measurements compared to simulations are presented that quantify the high energy hadron, thermal neutron and Si 1 MeV neutron equivalent fluences at the given test locations. A crucial part was to calibrate the beam monitoring systems to measure the number of protons, p.o.t., which is outlined using different techniques. In addition, cross-checks of p.o.t. measurements are pre...

  8. Radioiodination of chicken erythrocyte histones H4 and H5 in chromatin.

    Science.gov (United States)

    Griffiths, G R; Huang, P C

    1979-08-25

    The conformational state of histones in isolated chicken erythrocyte chromatin was studied using procedures developed for probing surface proteins on membranes. Under controlled conditions, only exposed tyrosyl residues react with iodide radicals, generated either by the oxidant, chloramine-T (paratoluenesulfonyl chloramide), or the enzyme lactoperoxidase, giving monoidotyrosine. Using 125-iodine, this study compared the reactive tyrosines in free and bound histones H4, and H5. The relative extent of iodination of these histones within (H4) and outside (H5) of the nucleosomes was measured after extraction and gel electrophoresis. Each of the histones was further analyzed for the extent of specific tyrosine iodination by separating the tryptic peptides by high voltage electrophoresis. The identity of the labeled peptide was determined by dansylation of the amino acids present in each hydrolyzed peptide. The results show that there is a difference in the conformational arrangement of these histones on chromatin and in the free forms, since in chromatin not all tyrosine residues are as accessible for iodination as in the denatured state. Residue 53 of histone H5 for instance is more reactive than residues 28 and 58, indicating that the segments containing the latter residues are involved in either protein-DNA or protein-protein interactions. In histone H4, preferential labeling of 2 of the 4 tyrosines present was also observed.

  9. A search for ortho-benzyne (o-C6H4) in CRL 618

    CERN Document Server

    Weaver, Susanna L Widicus; McMahon, Robert J; McCall, Benjamin J

    2007-01-01

    Polycyclic aromatic hydrocarbons (PAHs) have been proposed as potential carriers of the unidentified infrared bands (UIRs) and the diffuse interstellar bands (DIBs). PAHs are not likely to form by gas-phase or solid-state interstellar chemistry, but rather might be produced in the outflows of carbon-rich evolved stars. PAHs could form from acetylene addition to the phenyl radical (C6H5), which is closely chemically related to benzene (C6H6) and $ortho$-benzyne (o-C6H4). To date, circumstellar chemical models have been limited to only a partial treatment of benzene-related chemistry, and so the expected abundances of these species are unclear. A detection of benzene has been reported in the envelope of the proto-planetary nebula (PPN) CRL 618, but no other benzene-related species has been detected in this or any other source. The spectrum of o-C6H4 is significantly simpler and stronger than that of C6H5, and so we conducted deep Ku-, K- and Q-band searches for o-C6H4 with the Green Bank Telescope. No transitio...

  10. Experimental and kinetic modeling study of C2H4 oxidation at high pressure

    DEFF Research Database (Denmark)

    Lopez, Jorge Gimenez; Rasmussen, Christian Lund; Alzueta, Maria;

    2009-01-01

    A detailed chemical kinetic model for oxidation of C2H4 in the intermediate temperature range and high pressure has been developed and validated experimentally. New ab initio calculations and RRKM analysis of the important C2H3 + O-2 reaction was used to obtain rate coefficients over a wide range...... of conditions (0.003-100 bar, 200-3000 K). The results indicate that at 60 bar and medium temperatures vinyl peroxide, rather than CH2O and HCO, is the dominant product. The experiments, involving C2H4/O-2 mixtures diluted in N-2, were carried out in a high pressure flow reactor at 600-900 K and 60 bar, varying...... the reaction stoichiometry from very lean to fuel-rich conditions. Model predictions are generally satisfactory. The governing reaction mechanisms are outlined based on calculations with the kinetic model. Under the investigated conditions the oxidation pathways for C2H4 are more complex than those prevailing...

  11. H4K20me0 marks post-replicative chromatin and recruits the TONSL₋MMS22L DNA repair complex

    Energy Technology Data Exchange (ETDEWEB)

    Saredi, Giulia; Huang, Hongda; Hammond, Colin M.; Alabert, Constance; Bekker-Jensen, Simon; Forne, Ignasi; Reverón-Gómez, Nazaret; Foster, Benjamin M.; Mlejnkova, Lucie; Bartke, Till; Cejka, Petr; Mailand, Niels; Imhof, Axel; Patel, Dinshaw J.; Groth, Anja [UCopenhagen; (MSKCC); (ICL); (LMU); (Zurich)

    2016-06-22

    Here, we report that after DNA replication, chromosomal processes including DNA repair and transcription take place in the context of sister chromatids. While cell cycle regulation can guide these processes globally, mechanisms to distinguish pre- and post-replicative states locally remain unknown. In this paper we reveal that new histones incorporated during DNA replication provide a signature of post-replicative chromatin, read by the human TONSL–MMS22L1, 2, 3, 4 homologous recombination complex. We identify the TONSL ankyrin repeat domain (ARD) as a reader of histone H4 tails unmethylated at K20 (H4K20me0), which are specific to new histones incorporated during DNA replication and mark post-replicative chromatin until the G2/M phase of the cell cycle. Accordingly, TONSL–MMS22L binds new histones H3–H4 both before and after incorporation into nucleosomes, remaining on replicated chromatin until late G2/M. H4K20me0 recognition is required for TONSL–MMS22L binding to chromatin and accumulation at challenged replication forks and DNA lesions. Consequently, TONSL ARD mutants are toxic, compromising genome stability, cell viability and resistance to replication stress. Finally, together, these data reveal a histone-reader-based mechanism for recognizing the post-replicative state, offering a new angle to understand DNA repair with the potential for targeted cancer therapy.

  12. Characterization of a hemolytic protein, identified as histone H4, from the skin of the Japanese tree frog Hyla japonica (Hylidae).

    Science.gov (United States)

    Kawasaki, Hiroaki; Iwamuro, Shawichi; Goto, Yuta; Nielsen, Per F; Conlon, J Michael

    2008-01-01

    An extract of the skin of the Japanese tree frog, Hyla japonica Günther, 1859 (Anura: Hylidae) did not inhibit the growth of the bacteria Escherichia coli or Staphylococcus aureus, but contained a protein that was strongly hemolytic against human erythrocytes. The protein was purified to near homogeneity by reverse-phase HPLC, and its N-terminal amino acid sequence (SGRGKGGKGL...) identified it as histone H4. The complete primary structure of the 102-amino-acid-residue histone H4 was determined by a combination of molecular cloning of genomic and complementary DNAs encoding the protein. The molecular mass of the purified histone H4 determined by electrospray mass spectrometry was 71+/-2 Daltons greater than that predicted from the deduced amino acid sequence of the protein. The +71 mass units is consistent with the proposal that the protein isolated from the skin was post-translationally modified by addition of one acetyl and two methyl groups. The stem-loop structure at the 3' flanking region of the H. japonica histone H4 gene, which acts as a transcription termination signal, contained a nucleotide sequence (5'-GGCTCTCCTCAGAGCC-3') with unusual structural features not seen in other histone genes.

  13. Construction of J- and H- Aggregates of meso-Tetrakis (4-hydroxyphenyl) porphyrin Diacid (H4THPP2+)

    Institute of Scientific and Technical Information of China (English)

    Ying Hui ZHANG; Yang WU

    2005-01-01

    UV-Vis spectrum was utilized to study the aggregation behaviors of H4THPP2+ in DMF-chloroform mixture and water. It was found that J-aggregation of H4THPP2+ was formed in DMF-chloroform mixture and H-aggregate was formed in aqueous solution with high ionic-strength, as indicated by different spectral characteristics of different H4THPP2+ aggregates.

  14. Shedding light on avian influenza H4N6 infection in mallards: modes of transmission and implications for surveillance.

    Directory of Open Access Journals (Sweden)

    Kaci K VanDalen

    Full Text Available BACKGROUND: Wild mallards (Anas platyrhychos are considered one of the primary reservoir species for avian influenza viruses (AIV. Because AIV circulating in wild birds pose an indirect threat to agriculture and human health, understanding the ecology of AIV and developing risk assessments and surveillance systems for prevention of disease is critical. METHODOLOGY/PRINCIPAL FINDINGS: In this study, mallards were experimentally infected with an H4N6 subtype of AIV by oral inoculation or contact with an H4N6 contaminated water source. Cloacal swabs, oropharyngeal swabs, fecal samples, and water samples were collected daily and tested by real-time RT-PCR (RRT-PCR for estimation of viral shedding. Fecal samples had significantly higher virus concentrations than oropharyngeal or cloacal swabs and 6 month old ducks shed significantly more viral RNA than 3 month old ducks regardless of sample type. Use of a water source contaminated by AIV infected mallards, was sufficient to transmit virus to naïve mallards, which shed AIV at higher or similar levels as orally-inoculated ducks. CONCLUSIONS: Bodies of water could serve as a transmission pathway for AIV in waterfowl. For AIV surveillance purposes, water samples and fecal samples appear to be excellent alternatives or additions to cloacal and oropharyngeal swabbing. Furthermore, duck age (even within hatch-year birds may be important when interpreting viral shedding results from experimental infections or surveillance. Differential shedding among hatch-year mallards could affect prevalence estimates, modeling of AIV spread, and subsequent risk assessments.

  15. Quasi-Elastic Neutron Scattering (QENS) Studies of Hydrogen Dynamics for Nano-Confined NaAlH4

    Science.gov (United States)

    Dobbins, Tabbetha; Narasegowda, Shathabish; Brown, Craig; Tyagi, Madhusudan; Jenkins, Timothy

    The hydrogen dynamics of nano-confined sodium alanate (NaAlH4) has been studied using quasi-elastic neutron scattering (QENS). Results indicate thermodynamic destabilization is responsible for reduced desorption temperatures of NaAlH4 upon confinement within the nanopores of a metal organic framework (MOF). Both the bulk (microscale) NaAlH4 and the nanoconfined NaAlH4 data were fitted to re-orientation models which yielded corresponding percent mobile hydrogen and jump lengths. The jump lengths calculated from the nano-NaAlH4 were ~2.5 Å, and in conformity with those jump lengths determined for bulk NaAlH4 of ~2.3 Å. As much as 18 % of the hydrogen atoms were estimated to be mobile in the nano-NaAlH4 sample even at relatively low temperatures of 350 K. In contrast, bulk NaAlH4 shows less than 7 % mobile H-atoms even at higher temperatures of ~450 K. The activation energy for the long range is 3.1meV. Quasi-Elastic Neutron Scattering (QENS) Studies of Hydrogen Dynamics for Nano-Confined NaAlH4.

  16. Interview with Kortney Ryan Ziegler of the Trans*H4CK Project

    DEFF Research Database (Denmark)

    Raun, Tobias

    2014-01-01

    and content for trans communities. Raun and Ziegler discuss the usefulness of social entrepreneurship models to trans community formation, the importance of fostering digital activism by and for underrepresented communities, and the possibilities of circumventing traditional grant-making institutions......TSQ New Media editor Tobias Raun interviews Kortney Ryan Ziegler, the organizer of the Trans*H4CK hackathon, which took place in Oakland, California, in September 2013. The hackathon brought forty transgender, gender nonconforming, cisgender, and queer people together to create digital tools...... by raising seed money for trans activism through crowd funding....

  17. Calculations of the indirect nuclear spin-spin coupling constants of PbH4

    DEFF Research Database (Denmark)

    Kirpekar, Sheela; Sauer, Stephan P. A.

    1999-01-01

    We report ab initio calculations of the indirect nuclear spin-spin coupling constants of PbH4 using a basis set which was specially optimized for correlated calculations of spin-spin coupling constants. All nonrelativistic contributions and the most important part of the spin-orbit correction were...... approximation and the second-order polarization propagator approximation with coupled-cluster singles and doubles amplitudes. The effects of nuclear motion were investigated by calculating the coupling constants as a function of the totally symmetric stretching coordinate. We find that the Fermi contact term...

  18. Thermodynamics and kinetics of NaAlH4 nanocluster decomposition.

    Science.gov (United States)

    Bhakta, Raghunandan K; Maharrey, Sean; Stavila, Vitalie; Highley, Aaron; Alam, Todd; Majzoub, Eric; Allendorf, Mark

    2012-06-14

    Reactive nanoparticles are of great interest for applications ranging from catalysis to energy storage. However, efforts to relate cluster size to thermodynamic stability and chemical reactivity are hampered by broad pore size distributions and poorly characterized chemical environments in many microporous templates. Metal hydrides are an important example of this problem. Theoretical calculations suggest that reducing their critical dimension to the nanoscale can in some cases considerably destabilize these materials and there is clear experimental evidence for accelerated kinetics, making hydrogen storage applications more attractive in some cases. However, quantitative measurements establishing the influence of size on thermodynamics are lacking, primarily because carbon aerogels often used as supports provide inadequate control over size and pore chemistry. Here, we employ the nanoporous metal-organic framework (MOF) Cu-BTC (also known as HKUST-1) as a template to synthesize and confine the complex hydride NaAlH(4). The well-defined crystalline structure and monodisperse pore dimensions of this MOF allow detailed, quantitative probing of the thermodynamics and kinetics of H(2) desorption from 1-nm NaAlH(4) clusters (NaAlH(4)@Cu-BTC) without the ambiguity associated with amorphous templates. Hydrogen evolution rates were measured as a function of time and temperature using the Simultaneous Thermogravimetric Modulated Beam Mass Spectrometry method, in which sample mass changes are correlated with a complete analysis of evolved gases. NaAlH(4)@Cu-BTC undergoes a single-step dehydrogenation reaction in which the Na(3)AlH(6) intermediate formed during decomposition of the bulk hydride is not observed. Comparison of the thermodynamically controlled quasi-equilibrium reaction pathways in the bulk and nanoscale materials shows that the nanoclusters are slightly stabilized by confinement, having an H(2) desorption enthalpy that is 7 kJ (mol H(2))(-1) higher than the

  19. Literatuuronderzoek voertuigkering H4-niveau : een literatuurstudie naar voertuigkeringen beproefd op H4-niveau volgens prEN 1317-1 en prEN 1317-2. In opdracht van Bouwdienst Rijkswaterstaat, Apeldoorn.

    NARCIS (Netherlands)

    Pol, W.H.M. van de

    1997-01-01

    Not many full-scale tests at the H4 level have yet been carried out according to the first and second standards of the prEN 1317. For this reason, only a few H4 tests are mentioned in the literature. Full-scale tests conducted with heavy vehicles are also mentioned in the literature. These tests dev

  20. H4K20me0 marks post-replicative chromatin and recruits the TONSL–MMS22L DNA repair complex

    DEFF Research Database (Denmark)

    Saredi, Giulia; Huang, Hongda; Hammond, Colin M;

    2016-01-01

    that new histones incorporated during DNA replication provide a signature of post-replicative chromatin, read by the human TONSL–MMS22L homologous recombination complex. We identify the TONSL ankyrin repeat domain (ARD) as a reader of histone H4 tails unmethylated at K20 (H4K20me0), which are specific...... is required for TONSL–MMS22L binding to chromatin and accumulation at challenged replication forks and DNA lesions. Consequently, TONSL ARD mutants are toxic, compromising genome stability, cell viability and resistance to replication stress. Together, these data reveal a histone-reader-based mechanism...... for recognizing the post-replicative state, offering a new angle to understand DNA repair with the potential for targeted cancer therapy....

  1. Antifungal properties of wheat histones (H1-H4) and purified wheat histone H1.

    Science.gov (United States)

    De Lucca, Anthony J; Heden, Lars-Olof; Ingber, Bruce; Bhatnagar, Deepak

    2011-07-13

    Wheat ( Triticum spp.) histones H1, H2, H3, and H4 were extracted, and H1 was further purified. The effect of these histones on specific fungi that may or may not be pathogenic to wheat was determined. These fungi included Aspergillus flavus , Aspergillus fumigatus , Aspergillus niger , Fusarium oxysporum , Fusarium verticillioides , Fusarium solani , Fusarium graminearum , Penicillium digitatum , Penicillium italicum , and Greeneria uvicola . Non-germinated and germinating conidia of these fungi were bioassayed separately. The non-germinated and germinating conidia of all Fusarium species were highly susceptible to the mixture (H1-H4) as well as pure H1, with viability losses of 99-100% found to be significant (p histone mixture and pure H1. F. graminearum was the most sensitive to histone activity. The histones were inactive against all of the non-germinated Penicillium spp. conidia. However, they significantly reduced the viability of the germinating conidia of the Penicillium spp. conidia, with 95% loss at 2.5 μM. Non-germinated and germinating conidia viability of the Aspergillus spp. and G. uvicola were unaffected when exposed to histones up to 10 μM. Results indicate that Fusarium spp. pathogenic to wheat are susceptible to wheat histones, indicating that these proteins may be a resistance mechanism in wheat against fungal infection.

  2. Performance measurement of the upgraded Microcab-H4 with academic drive cycle

    Directory of Open Access Journals (Sweden)

    Luthfi Rais

    2016-05-01

    Full Text Available The original Microcab-H4, a hybrid fuel cell car, was tested with Academic drive cycle. After several years, the car was upgraded and tested with the ECE 15 drive cycle. The result showed the car has higher energy efficiency. However, the result could not be compared to the original car due to different drive cycle test. This research was done to measure the performance and energy efficiency of the Upgraded Microcab-H4 with Academic drive cycle. The measure of car energy efficiency was done through four tests: Run on battery, run on battery and Ballard fuel cell, and run on battery, Ballard, and Horizon fuel cell. The energy efficiency was calculated based on the hydrogen consumption after 5 cycles. The lowest energy efficiency was run on battery and Ballard fuel cell with (1.01 km/MJ. The highest energy efficiency was run on battery, Ballard, and Horizon fuel cells (1.10 km/MJ, which is higher than previous tests.

  3. The FACT histone chaperone guides histone H4 into its nucleosomal conformation in Saccharomyces cerevisiae.

    Science.gov (United States)

    McCullough, Laura; Poe, Bryan; Connell, Zaily; Xin, Hua; Formosa, Tim

    2013-09-01

    The pob3-Q308K mutation alters the small subunit of the Saccharomyces cerevisiae histone/nucleosome chaperone Facilitates Chromatin Transactions (FACT), causing defects in both transcription and DNA replication. We describe histone mutations that suppress some of these defects, providing new insight into the mechanism of FACT activity in vivo. FACT is primarily known for its ability to promote reorganization of nucleosomes into a more open form, but neither the pob3-Q308K mutation nor the compensating histone mutations affect this activity. Instead, purified mutant FACT complexes fail to release from nucleosomes efficiently, and the histone mutations correct this flaw. We confirm that pob3-T252E also suppresses pob3-Q308K and show that combining two suppressor mutations can be detrimental, further demonstrating the importance of balance between association and dissociation for efficient FACT:nucleosome interactions. To explain our results, we propose that histone H4 can adopt multiple conformations, most of which are incompatible with nucleosome assembly. FACT guides H4 to adopt appropriate conformations, and this activity can be enhanced or diminished by mutations in Pob3 or histones. FACT can therefore destabilize nucleosomes by favoring the reorganized state, but it can also promote assembly by tethering histones and DNA together and maintaining them in conformations that promote canonical nucleosome formation.

  4. High-pressure crystal structures and superconductivity of Stannane (SnH4).

    Science.gov (United States)

    Gao, Guoying; Oganov, Artem R; Li, Peifang; Li, Zhenwei; Wang, Hui; Cui, Tian; Ma, Yanming; Bergara, Aitor; Lyakhov, Andriy O; Iitaka, Toshiaki; Zou, Guangtian

    2010-01-26

    There is great interest in the exploration of hydrogen-rich compounds upon strong compression where they can become superconductors. Stannane (SnH(4)) has been proposed to be a potential high-temperature superconductor under pressure, but its high-pressure crystal structures, fundamental for the understanding of superconductivity, remain unsolved. Using an ab initio evolutionary algorithm for crystal structure prediction, we propose the existence of two unique high-pressure metallic phases having space groups Ama2 and P6(3)/mmc, which both contain hexagonal layers of Sn atoms and semimolecular (perhydride) H(2) units. Enthalpy calculations reveal that the Ama2 and P6(3)/mmc structures are stable at 96-180 GPa and above 180 GPa, respectively, while below 96 GPa SnH(4) is unstable with respect to elemental decomposition. The application of the Allen-Dynes modified McMillan equation reveals high superconducting temperatures of 15-22 K for the Ama2 phase at 120 GPa and 52-62 K for the P6(3)/mmc phase at 200 GPa.

  5. Histone H4 acetylation required for chromatin decompaction during DNA replication.

    Science.gov (United States)

    Ruan, Kun; Yamamoto, Takaharu G; Asakawa, Haruhiko; Chikashige, Yuji; Kimura, Hiroshi; Masukata, Hisao; Haraguchi, Tokuko; Hiraoka, Yasushi

    2015-07-30

    Faithful DNA replication is a prerequisite for cell proliferation. Several cytological studies have shown that chromosome structures alter in the S-phase of the cell cycle. However, the molecular mechanisms behind the alteration of chromosome structures associated with DNA replication have not been elucidated. Here, we investigated chromatin structures and acetylation of specific histone residues during DNA replication using the meiotic nucleus of the fission yeast Schizosaccharomyces pombe. The S. pombe meiotic nucleus provides a unique opportunity for measuring the levels of compaction of chromatin along the chromosome in a defined orientation. By direct measurement of chromatin compaction in living cells, we demonstrated that decompaction of chromatin occurs during meiotic DNA replication. This chromatin decompaction was suppressed by depletion of histone acetyltransferase Mst1 or by arginine substitution of specific lysine residues (K8 and K12) of histone H4. These results suggest that acetylation of histone H4 residues K8 and K12 plays a critical role in loosening chromatin structures during DNA replication.

  6. Microbial community analysis of pH 4 thermal springs in Yellowstone National Park.

    Science.gov (United States)

    Jiang, Xiaoben; Takacs-Vesbach, Cristina D

    2017-01-01

    The pH of the majority of thermal springs in Yellowstone National Park (YNP) is from 1 to 3 and 6 to 10; relatively few springs (~5%) have a pH range of 4-5. We used 16S rRNA gene pyrosequencing to investigate microbial communities sampled from four pH 4 thermal springs collected from four regions of YNP that differed in their fluid temperature and geochemistry. Our results revealed that the composition of bacterial communities varied among the sites, despite sharing similar pH values. The taxonomic composition and metabolic functional potential of the site with the lowest temperature (55 °C), a thermal spring from the Seven Mile Hole (SMH) area, were further investigated using shotgun metagenome sequencing. The taxonomic classification, based on 372 Mbp of unassembled metagenomic reads, indicated that this community included a high proportion of Chloroflexi, Bacteroidetes, Proteobacteria, and Firmicutes. Functional comparison with other YNP thermal spring metagenomes indicated that the SMH metagenome was enriched in genes related to energy production and conversion, transcription, and carbohydrate transport. Analysis of genes involved in nitrogen metabolism revealed assimilatory and dissimilatory nitrate reduction pathways, whereas the majority of genes involved in sulfur metabolism were related to the reduction of sulfate to adenylylsulfate, sulfite, and H2S. Given that pH 4 thermal springs are relatively less common in YNP and thermal areas worldwide, they may harbor novel microbiota and the communities that inhabit them deserve further investigation.

  7. Detection of Soluble B7-H4 Molecules in Serum of Patients with Breast Cancer and its Clinical Signiifcance

    Institute of Scientific and Technical Information of China (English)

    Chen Junjun; Shi Hongbing; Zheng Xiao; Cheng Gui; Xie Jun; Chen Lujun; Jiang Jingting; Wu Changping

    2013-01-01

    Objective:To investigate the expression of soluble B7-H4 molecules (soluble B7-H4, sB7-H4) in serum of patients with breast cancer and its clinical signiifcance. Methods:Seventy patients with breast cancer, 41 patients with benign breast disease and 28 healthy females were respectively selected as breast cancer group, benign control group and healthy control group. Enzyme-linked immunosorbent assay (ELISA) was applied to detect the content of serum sB7-H4 in three groups, and the clinical correlation with content of serum sB7-H4 in patients with breast cancer was analyzed. Besides, the expression of B7-H4 mRNA and proteins in breast cancer tissue and normal tissue adjacent to cancer was detected respectively with polymerase chain reaction (PCR) and immunohistochemical method. Results:The content of serum sB7-H4 in breast cancer group was obviously higher than in benign control group (U = 844.0, P Conclusion:In serum of patients with breast cancer, the content of sB7-H4 is increased notably and related to lymph node metastasis, hence it can be considered as a potential serum marker in the diagnosis and treatment of breast cancer.

  8. Clipping of flexible tails of histones H3 and H4 affects the structure and dynamics of the nucleosome.

    Science.gov (United States)

    Nurse, Nathan P; Jimenez-Useche, Isabel; Smith, Ian Tad; Yuan, Chongli

    2013-03-05

    Förster resonance energy transfer was used to monitor the dynamic conformations of mononucleosomes under different chromatin folding conditions to elucidate the role of the flexible N-terminal regions of H3 and H4 histones. The H3 tail was shown to partake in intranucleosomal interactions by restricting the DNA breathing motion and compacting the nucleosome. The H3 tail effects were mostly independent of the ionic strength and valency of the ions. The H4 tail was shown to not greatly affect the nucleosome conformation, but did slightly influence the relative population of the preferred conformation. The role of the H4 tail varied depending on the valency and ionic strength, suggesting that electrostatic forces play a primary role in H4 tail interactions. Interestingly, despite the H4 tail's lack of influence, when H3 and H4 tails were simultaneously clipped, a more dramatic effect was seen than when only H3 or H4 tails were clipped. The combinatorial effect of H3 and H4 tail truncation suggests a potential mechanism by which various combinations of histone tail modifications can be used to control accessibility of DNA-binding proteins to nucleosomal DNA. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. The role of histamine H1 and H4 receptors in atopic dermatitis: from basic research to clinical study.

    Science.gov (United States)

    Ohsawa, Yusuke; Hirasawa, Noriyasu

    2014-12-01

    Histamine plays important roles in inflammation and nervous irritability in allergic disorders, including atopic dermatitis (AD). It has been shown to regulate the expression of pruritic factors, such as nerve growth factor and semaphorin 3A, in skin keratinocytes via histamine H1 receptor (H1R). Furthermore, H1R antagonist reduced the level of IL-31, a cytokine involving the skin barrier and pruritus, in chronic dermatitis lesions in NC/Nga mice and patients with AD. Histamine plays roles in the induction of allergic inflammation by activating eosinophils, mast cells, basophils, and Th2 cells via histamine H4 receptor (H4R). H4R, in addition to H1R, is expressed on sensory neurons, and a decrease in scratching behaviors was observed in H4R-deficient mice and mice treated with a H4R antagonist. We found that the combined administration of H1R and H4R antagonists inhibited the itch response and chronic allergic inflammation, and had a pharmacological effect similar to that of prednisolone. Although the oral administration of H1R antagonists is widely used to treat AD, it is not very effective. In contrast, JNJ39758979, a novel H4R antagonist, had marked effects against pruritus in Japanese patients with AD in a phase II clinical trial. Next generation antihistaminic agents possessing H1R and H4R antagonistic actions may be a potent therapeutic drug for AD.

  10. A silencing pathway to induce H3-K9 and H4-K20 trimethylation at constitutive heterochromatin.

    Science.gov (United States)

    Schotta, Gunnar; Lachner, Monika; Sarma, Kavitha; Ebert, Anja; Sengupta, Roopsha; Reuter, Gunter; Reinberg, Danny; Jenuwein, Thomas

    2004-06-01

    Histone lysine methylation is a central modification to mark functionally distinct chromatin regions. In particular, H3-K9 trimethylation has emerged as a hallmark of pericentric heterochromatin in mammals. Here we show that H4-K20 trimethylation is also focally enriched at pericentric heterochromatin. Intriguingly, H3-K9 trimethylation by the Suv39h HMTases is required for the induction of H4-K20 trimethylation, although the H4 Lys 20 position is not an intrinsic substrate for these enzymes. By using a candidate approach, we identified Suv4-20h1 and Suv4-20h2 as two novel SET domain HMTases that localize to pericentric heterochromatin and specifically act as nucleosomal H4-K20 trimethylating enzymes. Interaction of the Suv4-20h enzymes with HP1 isoforms suggests a sequential mechanism to establish H3-K9 and H4-K20 trimethylation at pericentric heterochromatin. Heterochromatic H4-K20 trimethylation is evolutionarily conserved, and in Drosophila, the Suv4-20 homolog is a novel PEV modifier to regulate position-effect variegation. Together, our data indicate a function for H4-K20 trimethylation in gene silencing and further suggest H3-K9 and H4-K20 trimethylation as important components of a repressive pathway that can index pericentric heterochromatin.

  11. Histone H4 Lys 20 methyltransferase SET8 promotes androgen receptor-mediated transcription activation in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Lushuai [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Yanyan; Du, Fengxia [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); Han, Xiao [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xiaohua [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); Niu, Yuanjie [Chawnshang Chang Sex Hormone Research Center, Tianjin Institute of Urology, Tianjin Medical University, Tianjin 300070 (China); Ren, Shancheng, E-mail: renshancheng@gmail.com [Department of Urology, Shanghai Changhai Hospital, Second Military Medical University, Shanghai 200433 (China); Sun, Yingli, E-mail: sunyl@big.ac.cn [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China)

    2014-07-18

    Highlights: • Dihydrotestosterone stimulates H4K20me1 enrichment at the PSA promoter. • SET8 promotes AR-mediated transcription activation. • SET8 interacts with AR and promotes cell proliferation. - Abstract: Histone methylation status in different lysine residues has an important role in transcription regulation. The effect of H4K20 monomethylation (H4K20me1) on androgen receptor (AR)-mediated gene transcription remains unclear. Here we show that AR agonist stimulates the enrichment of H4K20me1 and SET8 at the promoter of AR target gene PSA in an AR dependent manner. Furthermore, SET8 is crucial for the transcription activation of PSA. Co-immunoprecipitation analyses demonstrate that SET8 interacts with AR. Therefore, we conclude that SET8 is involved in AR-mediated transcription activation, possibly through its interaction with AR and H4K20me1 modification.

  12. Equilibrium concentrations of N2H4 and its decomposition products at elevated temperatures and pressures

    Science.gov (United States)

    Smetana, F. O.; Fairchild, H. N., III; Martin, G. L.

    1973-01-01

    Liquid hydrazine is considered as a convenient source of hydrogen rather than just as a rocket fuel. For such purposes, the hydrogen is usually obtained by passing the hydrazine through a heated catalytic bed. One convenient measure of the effectiveness of a catalytic decomposition device as a whole is to compare the quantity of hydrogen produced with the equilibrium concentration of the gaseous species N2H4, NH3, N3, and H2 which would exist at the temperature and pressure found in various parts of the device. Calculations of the concentrations were carried out and are reported here. Following presentation of the results in both tabular and graphical forms is a comparison between the computed equilibrium concentrations and available experimental data.

  13. Muon-flux measurements for SHiP at H4

    CERN Document Server

    van Herwijnen, E

    2017-01-01

    A major concern for the design of the SHiP experiment is the lack of a precise knowledge of the muon flux. This is a proposal to measure the expected muon flux in the SHiP experiment by installing a replica of the SHiP target in a 400 GeV/c proton beam at H4. We intend building a spectrometer using the drift tube prototypes that were constructed for OPERA. A muon tagger will be built using RPCs, which will also serve as a module-0 for SHiP. We propose to do this measurement in early 2018. Accumulating $\\sim 10^{11}$ 400 GeV/c POT will enable us to make a more realistic design of the muon shield. With some modifications, this setup can also be used to measure the charm cross section (including the cascade production). We intend to test this setup after the measurement of the muon flux.

  14. Teledyne H1RG, H2RG, and H4RG Noise Generator

    CERN Document Server

    Rauscher, Bernard J

    2015-01-01

    This paper describes the near-infrared detector system noise generator (NG) that we wrote for the James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec). NG simulates many important noise components including; (1) white "read noise," (2) residual bias drifts, (3) pink $1/f$ noise, (4) alternating column noise, and (5) picture frame noise. By adjusting the input parameters, NG can simulate noise for Teledyne's H1RG, H2RG, and H4RG detectors with and without Teledyne's SIDECAR ASIC IR array controller. NG can be used as a starting point for simulating astronomical scenes by adding dark current, scattered light, and astronomical sources into the results from NG. NG is written in Python-3.4. The source code is freely available for download from http://jwst.nasa.gov/publications.html.

  15. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    Directory of Open Access Journals (Sweden)

    Alpers Charles N

    2007-10-01

    Full Text Available Abstract Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5. The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1 preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2 stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2–3 ‰ heavier in the mine water, relative to those in surface waters; (3 reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA and denaturing gradient gel electrophoresis (DGGE analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures.

  16. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    Science.gov (United States)

    Church, C.D.; Wilkin, R.T.; Alpers, C.N.; Rye, R.O.; Blaine, R.B.

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

  17. Satellite observations of ethylene (C2H4) from the Aura Tropospheric Emission Spectrometer: A scoping study

    Science.gov (United States)

    Dolan, Wayana; Payne, Vivienne H.; Kualwik, Susan S.; Bowman, Kevin W.

    2016-09-01

    We present a study focusing on detection and initial quantitative estimates of ethylene (C2H4) in observations from the Tropospheric Emission Spectrometer (TES), a Fourier transform spectrometer aboard the Aura satellite that measures thermal infrared radiances with high spectral resolution (0.1 cm-1). We analyze observations taken in support of the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission and demonstrate the feasibility of future development of C2H4 into a TES standard product. In the Northern Hemisphere, C2H4 is commonly associated with boreal fire plumes, motor vehicle exhaust and petrochemical emissions. It has a short lifetime (∼14-32 h) in the troposphere due to its reaction with OH and O3. Chemical destruction of C2H4 in the atmosphere leads to the production of ozone and other species such as carbon monoxide (CO) and formaldehyde. Results indicate a correlation between C2H4 and CO in boreal fire plumes. Quantitative C2H4 estimates are sensitive to assumptions about the plume height and width. We find that C2H4 greater than 2-3 ppbv can be detected in a single TES observation (for a fire plume at 3 km altitude and 1.5 km width). Spatial averaging will be needed for surface-peaking profiles where TES sensitivity is lower.

  18. Remarkably improved hydrogen storage properties of NaAlH4 doped with 2D titanium carbide

    Science.gov (United States)

    Wu, Ruyan; Du, Hufei; Wang, Zeyi; Gao, Mingxia; Pan, Hongge; Liu, Yongfeng

    2016-09-01

    A 2D Ti3C2 MXene is introduced into NaAlH4 to improve its hydrogen storage properties for the first time. In the presence of Ti3C2, the operating temperatures for hydrogen storage in NaAlH4 are remarkably reduced, and the hydrogenation/dehydrogenation kinetics are significantly enhanced. The onset dehydrogenation temperature of the 7 wt% Ti3C2-containing NaAlH4 sample is reduced to 100 °C, and hydrogen recharging starts at 50 °C. Approximately 4.7 wt% hydrogen is released from the NaAlH4-7 wt% Ti3C2 sample within 100 min at 140 °C, and the dehydrogenated sample absorbs 4.6 wt% hydrogen within 60 min at 120 °C. However, pristine NaAlH4 only absorbs 0.4 wt% hydrogen under identical conditions. Further cycling measurements show significantly improved cycling stability for the Ti3C2-containing NaAlH4; the hydrogenation/dehydrogenation behaviour remains nearly constant after 10 cycles. XRD and XPS analyses reveal that the Ti3C2 reacts with NaAlH4 and is reduced to metallic Ti and Ti3+ species, which are responsible for the lowered operating temperatures and improved dehydrogenation/hydrogenation kinetics.

  19. Microwave spectra of the SiH4-H2O complex: A new sort of intermolecular interaction

    Science.gov (United States)

    Kawashima, Yoshiyuki; Suenram, Richard D.; Hirota, Eizi

    2016-09-01

    Microwave spectral patterns observed for the silane-water complex were found much different from those of the methane-water complex. The SiH4-H2O complex is likely to have a tightly bound structure. The effective rotational and centrifugal distortion constants: B = 3621.1193 (45) MHz and DJ = 49.84 (30) kHz led to the distance between the Si and O atoms in the complex to be 3.3 Å, much shorter than the C and O separation in the CH4-H2O of 3.7 Å, and to the silane-water stretching force constant and stretching frequency to be 2.88 N/m and 65 cm-1, respectively, which are to be compared with 1.52 N/m and 55 cm-1 of the CH4-H2O. The characteristic features of the spectra observed for the main species 28SiH4-H2O are common to those of isotopic species: 29SiH4-H2O, 30SiH4-H2O, 28SiH4-H218O, 28SiH4-D2O, 29SiH4-D2O, 30SiH4-D2O, 28SiH4-HDO, 29SiH4-HDO, 30SiH4-HDO, 28SiD4-H2O, 28SiD4-D2O, and 28SiD4-HDO. The observed spectra also indicate that the silane executes a threefold internal rotation about one of its four Si-H bonds, while the C2 symmetry axis of the water is bent away from the internal-rotation axis. An internal axis method analysis yielded an estimate of the internal-rotation potential barrier V3 to be 140 ± 50 cm-1, and those based on diagonalization of a principal axis method Hamiltonian matrix and on the extended internal axis method resulted in V3 ranging from 180 to 100 cm-1, depending on the isotopic species studied. All the measurements were done by using a pulsed nozzle Fourier transform microwave spectrometer, and the spectral assignments were made with the aid of the Stark effect, which yielded the dipole moment to be 1.730 (10) D. Transitions in higher energy states of the SiH4 internal rotation were observed, clearly resolved from the main lines, when the carrier gas was replaced from Ar to Ne.

  20. Rheological properties of gamma irradiated [Me3NC2H4OH]+[Zn2Cl5]- and [Me3NC2H4OH]+[Zn3Cl7]- ionic liquids

    Institute of Scientific and Technical Information of China (English)

    李倩妹; 罗迎社; 吴国忠; 陈仕谋

    2008-01-01

    The objective of this work is to verify the rheological behavior of irradiated [Me3NC2H4OH]+[Zn2Cl5]-and [Me3NC2H4OH]+[Zn3Cl7]-ionic liquids in comparison to the unirradiated ones,the viscosities were measured by a strain-control experiment under different irradiation doses’ samples(0,10,20,50,100 kGy) at different shear rates and temperatures.The curves of shear stress against shear rate present that the viscosity of ionic liquid is insensitive to shear rate;the viscosity of ionic liquids decreases with increasing temperature,and can be fitted by Arrhenius equation very well.Gamma radiation causes a decrease of viscosity of [Me3NC2H4OH]+[Zn3Cl7]-by greater than 10%,but it does not impair the viscosity of [Me3NC2H4OH]+[Zn2Cl5]-(within the experimental error) except 20 kGy irradiated sample.The results show that the radiation stability of [Me3NC2H4OH]+[Zn2Cl5]-is higher than that of [Me3NC2H4OH]+[Zn3Cl7]-.

  1. Kaolinite dissolution and precipitation kinetics at 22oC and pH 4

    Energy Technology Data Exchange (ETDEWEB)

    Steefel, Carl; Yang, L.; Steefel, C.I.

    2008-04-01

    Dissolution and precipitation rates of low defect Georgia kaolinite (KGa-1b) as a function of Gibbs free energy of reaction (or reaction affinity) were measured at 22 C and pH 4 in continuously stirred flowthrough reactors. Steady state dissolution experiments showed slightly incongruent dissolution, with a Si/Al ratio of about 1.12 that is attributed to the re-adsorption of Al on to the kaolinite surface. No inhibition of the kaolinite dissolution rate was apparent when dissolved aluminum was varied from 0 and 60 {micro}M. The relationship between dissolution rates and the reaction affinity can be described well by a Transition State Theory (TST) rate formulation with a Temkin coefficient of 2 R{sub diss} (mol/m{sup 2}s) = 1.15 x 10{sup -13} [1-exp(-{Delta}G/2RT)]. Stopping of flow in a close to equilibrium dissolution experiment yielded a solubility constant for kaolinite at 22 C of 10{sup 7.57}. Experiments on the precipitation kinetics of kaolinite showed a more complex behavior. One conducted using kaolinite seed that had previously undergone extensive dissolution under far from equilibrium conditions for 5 months showed a quasi-steady state precipitation rate for 105 hours that was compatible with the TST expression above. After this initial period, however, precipitation rates decreased by an order of magnitude, and like other precipitation experiments conducted at higher supersaturation and without kaolinite seed subjected to extensive prior dissolution, could not be described with the TST law. The initial quasi-steady state rate is interpreted as growth on activated sites created by the dissolution process, but this reversible growth mechanism could not be maintained once these sites were filled. Long-term precipitation rates showed a linear dependence on solution saturation state that is generally consistent with a two dimensional nucleation growth mechanism following the equation R{sub ppt}(mol/m{sup 2}s) = 3.38 x 10{sup -14} exp[- 181776/T{sup 2} 1n

  2. Histone H4 hyperacetylation and rapid turnover of its acetyl groups in transcriptionally inactive rooster testis spermatids.

    Science.gov (United States)

    Oliva, R; Mezquita, C

    1982-12-20

    In order to study the relationship between acetylation of histones, chromatin structure and gene activity, the distribution and turnover of acetyl groups among nucleosomal core histones and the extent of histone H4 acetylation were examined in rooster testis cell nuclei at different stages of spermatogenesis. Histone H4 was the predominant acetylated histone in mature testes. Hyperacetylation of H4 and rapid turnover of its acetyl groups are not univocally correlated with transcriptional activity since they were detected in both genetically active testicular cells and genetically inactive elongated spermatids. During the transition from nucleohistone to nucleoprotamine in elongated spermatids the chromatin undergoes dramatic structural changes with exposition of binding sites on DNA (1). Hyperacetylation of H4 and rapid turnover of its acetyl groups could be correlated with the particular conformation of chromatin in elongated spermatids and might represent a necessary condition for binding of chromosomal proteins to DNA.

  3. Distinct signalling pathways of murine histamine H1- and H4-receptors expressed at comparable levels in HEK293 cells.

    Directory of Open Access Journals (Sweden)

    Silke Beermann

    Full Text Available Histamine (HA is recognized by its target cells via four G-protein-coupled receptors, referred to as histamine H1-receptor (H1R, H2R, H3R, and H4R. Both H1R and H4R exert pro-inflammatory functions. However, their signal transduction pathways have never been analyzed in a directly comparable manner side by side. Moreover, the analysis of pharmacological properties of the murine orthologs, representing the main targets of pre-clinical research, is very important. Therefore, we engineered recombinant HEK293 cells expressing either mouse (mH1R or mH4R at similar levels and analyzed HA-induced signalling in these cells. HA induced intracellular calcium mobilization via both mH1R and mH4R, with the mH1R being much more effective. Whereas cAMP accumulation was potentiated via the mH1R, it was reduced via the mH4R. The regulation of both second messengers via the H4R, but not the H1R, was sensitive to pertussis toxin (PTX. The mitogen-activated protein kinases (MAPKs ERK 1/2 were massively activated downstream of both receptors and demonstrated a functional involvement in HA-induced EGR-1 gene expression. The p38 MAPK was moderately activated via both receptors as well, but was functionally involved in HA-induced EGR-1 gene expression only in H4R-expressing cells. Surprisingly, in this system p38 MAPK activity reduced the HA-induced gene expression. In summary, using this system which allows a direct comparison of mH1R- and mH4R-induced signalling, qualitative and quantitative differences on the levels of second messenger generation and also in terms of p38 MAPK function became evident.

  4. Structural basis for recognition of H3K56-acetylated histone H3-H4 by the chaperone Rtt106

    Energy Technology Data Exchange (ETDEWEB)

    Su, Dan; Hu, Qi; Li, Qing; Thompson, James R; Cui, Gaofeng; Fazly, Ahmed; Davies, Brian A; Botuyan, Maria Victoria; Zhang, Zhiguo; Mer, Georges [Mayo

    2013-04-08

    Dynamic variations in the structure of chromatin influence virtually all DNA-related processes in eukaryotes and are controlled in part by post-translational modifications of histones. One such modification, the acetylation of lysine 56 (H3K56ac) in the amino-terminal α-helix (αN) of histone H3, has been implicated in the regulation of nucleosome assembly during DNA replication and repair, and nucleosome disassembly during gene transcription. In Saccharomyces cerevisiae, the histone chaperone Rtt106 contributes to the deposition of newly synthesized H3K56ac-carrying H3-H4 complex on replicating DNA, but it is unclear how Rtt106 binds H3-H4 and specifically recognizes H3K56ac as there is no apparent acetylated lysine reader domain in Rtt106. Here, we show that two domains of Rtt106 are involved in a combinatorial recognition of H3-H4. An N-terminal domain homodimerizes and interacts with H3-H4 independently of acetylation while a double pleckstrin-homology (PH) domain binds the K56-containing region of H3. Affinity is markedly enhanced upon acetylation of K56, an effect that is probably due to increased conformational entropy of the αN helix of H3. Our data support a mode of interaction where the N-terminal homodimeric domain of Rtt106 intercalates between the two H3-H4 components of the (H3-H4)2 tetramer while two double PH domains in the Rtt106 dimer interact with each of the two H3K56ac sites in (H3-H4)2. We show that the Rtt106-(H3-H4)2 interaction is important for gene silencing and the DNA damage response.

  5. ZnSe·0.5N2H4 hybrid nanostructures: a promising alternative photocatalyst for solar conversion.

    Science.gov (United States)

    Chen, Yu-Chih; Liu, Tao-Cheng; Hsu, Yung-Jung

    2015-01-28

    As the molecular precursor of ZnSe, ZnSe·0.5N2H4 inorganic-organic hybrids have received relatively less attention due to the feasibility of their further processing and decomposition into pure-phase ZnSe. Here we demonstrated that ZnSe·0.5N2H4 hybrid nanostructures, which were prepared using a facile hydrazine-assisted hydrothermal method, may practically harvest solar energy for photoconversion applications. By modulating the volume ratio of hydrazine hydrate to deionized water employed in the synthesis, the morphology of the grown ZnSe·0.5N2H4 can be varied, which included nanowires, nanobelts and nanoflakes. With the relatively long exciton lifetime and highly anisotropic structure, ZnSe·0.5N2H4 nanowires performed much better in the photodegradation of rhodamine B than the other two counterpart products. As compared to pure ZnSe nanoparticles and single-phase ZnSe nanowires obtained from further processing ZnSe·0.5N2H4, the ZnSe·0.5N2H4 hybrid nanowires exhibited superior photocatalytic performance under visible light illumination. The hybrid nanowires were further decorated with Au particles to endow them with structural and compositional diversities. Time-resolved photoluminescence spectra suggested that almost 40% of the photoexcited electrons in ZnSe·0.5N2H4 nanowires can be transported to the decorated Au, which enabled a fuller extent of participation of charge carriers in the photocatalytic process and thus conduced to a significant enhancement in the photocatalytic activity. The demonstrations from this work illustrate that ZnSe·0.5N2H4 hybrid nanostructures can serve as a versatile photocatalyst platform for advanced photocatalytic applications.

  6. The Role of Histamine H1 and H4 Receptors in Atopic Dermatitis: From Basic Research to Clinical Study

    Directory of Open Access Journals (Sweden)

    Yusuke Ohsawa

    2014-01-01

    Although the oral administration of H1R antagonists is widely used to treat AD, it is not very effective. In contrast, JNJ39758979, a novel H4R antagonist, had marked effects against pruritus in Japanese patients with AD in a phase II clinical trial. Next generation antihistaminic agents possessing H1R and H4R antagonistic actions may be a potent therapeutic drug for AD.

  7. Role of swi7H4 mutant allele of DNA polymerase α in the DNA damage checkpoint response.

    Science.gov (United States)

    Khan, Saman; Ahmed, Shakil

    2015-01-01

    Besides being a mediator of initiation of DNA replication, DNA polymerase α plays a key role in chromosome maintenance. Swi7H4, a novel temperature sensitive mutant of DNA polymerase α was shown to be defective in transcriptional silencing at the mating type centromere and telomere loci. It is also required for the establishment of chromatin state that can recruit the components of the heterochromatin machinery at these regions. Recently the role of DNA polymerase α in the S-phase alkylation damage response in S. pombe has also been studied. Here we investigate whether defects generated by swi7H4, a mutant allele of DNA polymerase α can activate a checkpoint response. We show that swi7H4 exhibit conditional synthetic lethality with chk1 null mutant and the double mutant of swi7H4 with chk1 deletion aggravate the chromosome segregation defects. More importantly swi7H4 mutant cells delay the mitotic progression at non permissive temperature that is mediated by checkpoint protein kinase Chk1. In addition we show that, in the swi7H4 mutant background, cells accumulate DNA damage at non permissive temperature activating the checkpoint kinase protein Chk1. Further, we observed synthetic lethality between swi7H4 and a number of genes involved in DNA repair pathway at semi permissive temperature. We summarize that defects in swi7H4 mutant results in DNA damage that delay mitosis in a Chk1 dependent manner that also require the damage repair pathway for proper recovery.

  8. Role of swi7H4 mutant allele of DNA polymerase α in the DNA damage checkpoint response.

    Directory of Open Access Journals (Sweden)

    Saman Khan

    Full Text Available Besides being a mediator of initiation of DNA replication, DNA polymerase α plays a key role in chromosome maintenance. Swi7H4, a novel temperature sensitive mutant of DNA polymerase α was shown to be defective in transcriptional silencing at the mating type centromere and telomere loci. It is also required for the establishment of chromatin state that can recruit the components of the heterochromatin machinery at these regions. Recently the role of DNA polymerase α in the S-phase alkylation damage response in S. pombe has also been studied. Here we investigate whether defects generated by swi7H4, a mutant allele of DNA polymerase α can activate a checkpoint response. We show that swi7H4 exhibit conditional synthetic lethality with chk1 null mutant and the double mutant of swi7H4 with chk1 deletion aggravate the chromosome segregation defects. More importantly swi7H4 mutant cells delay the mitotic progression at non permissive temperature that is mediated by checkpoint protein kinase Chk1. In addition we show that, in the swi7H4 mutant background, cells accumulate DNA damage at non permissive temperature activating the checkpoint kinase protein Chk1. Further, we observed synthetic lethality between swi7H4 and a number of genes involved in DNA repair pathway at semi permissive temperature. We summarize that defects in swi7H4 mutant results in DNA damage that delay mitosis in a Chk1 dependent manner that also require the damage repair pathway for proper recovery.

  9. A role for the H4 subunit of vaccinia RNA polymerase in transcription initiation at a viral early promoter.

    Science.gov (United States)

    Deng, L; Shuman, S

    1994-05-13

    The vaccinia virus H4 gene encodes an essential subunit of the DNA-dependent RNA polymerase holoenzyme encapsidated within virus particles (Ahn, B., and Moss, B. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 3536-3540; Kane, E. M., and Shuman, S. (1992) J. Virol. 66, 5752-5762). The role of this protein in transcription of viral early genes was revealed by the effects of affinity-purified anti-H4 antibody on discrete phases of the early transcription reaction in vitro. Anti-H4 specifically prevented the synthesis of a 21-nucleotide nascent RNA chain but had no impact on elongation of the 21-mer RNA by preassembled ternary complexes. Inhibition of initiation but not elongation was also observed with affinity-purified anti-D6 antibody directed against the 70-kDa subunit of the vaccinia early transcription initiation factor (ETF). Native gel mobility-shift assays showed that anti-H4 prevented the NTP-dependent recruitment of RNA polymerase to the preinitiation complex of ETF bound at the early promoter. Two species of ternary complexes could be resolved by native gel electrophoresis. Addition of anti-H4 to preformed complexes elicited a supershift of both ternary species but not of the preinitiation complex. Supeshift by anti-D6 revealed that the more rapidly migrating species of ternary complex did not contain immunoreactive ETF. Loss of ETF from the ternary complex was time-dependent. Thus, whereas the H4 protein was a stable constituent of the elongation complex, ETF was dissociable. We suggest that H4 functions as a molecular bridge to ETF and thereby allows specific recognition of early promoters by the core RNA polymerase. H4 is unlike bacterial sigma factor in that it remains bound to polymerase after the elongation complex is established.

  10. H4K20me1 contributes to downregulation of X-linked genes for C. elegans dosage compensation.

    Science.gov (United States)

    Vielle, Anne; Lang, Jackie; Dong, Yan; Ercan, Sevinc; Kotwaliwale, Chitra; Rechtsteiner, Andreas; Appert, Alex; Chen, Q Brent; Dose, Andrea; Egelhofer, Thea; Kimura, Hiroshi; Stempor, Przemyslaw; Dernburg, Abby; Lieb, Jason D; Strome, Susan; Ahringer, Julie

    2012-09-01

    The Caenorhabditis elegans dosage compensation complex (DCC) equalizes X-chromosome gene dosage between XO males and XX hermaphrodites by two-fold repression of X-linked gene expression in hermaphrodites. The DCC localizes to the X chromosomes in hermaphrodites but not in males, and some subunits form a complex homologous to condensin. The mechanism by which the DCC downregulates gene expression remains unclear. Here we show that the DCC controls the methylation state of lysine 20 of histone H4, leading to higher H4K20me1 and lower H4K20me3 levels on the X chromosomes of XX hermaphrodites relative to autosomes. We identify the PR-SET7 ortholog SET-1 and the Suv4-20 ortholog SET-4 as the major histone methyltransferases for monomethylation and di/trimethylation of H4K20, respectively, and provide evidence that X-chromosome enrichment of H4K20me1 involves inhibition of SET-4 activity on the X. RNAi knockdown of set-1 results in synthetic lethality with dosage compensation mutants and upregulation of X-linked gene expression, supporting a model whereby H4K20me1 functions with the condensin-like C. elegans DCC to repress transcription of X-linked genes. H4K20me1 is important for mitotic chromosome condensation in mammals, suggesting that increased H4K20me1 on the X may restrict access of the transcription machinery to X-linked genes via chromatin compaction.

  11. Denitrification at pH 4 by a soil-derived Rhodanobacter-dominated community.

    Science.gov (United States)

    van den Heuvel, R N; van der Biezen, E; Jetten, M S M; Hefting, M M; Kartal, B

    2010-12-01

    Soil denitrification is a major source of nitrous oxide emission that causes ozone depletion and global warming. Low soil pH influences the relative amount of N₂O produced and consumed by denitrification. Furthermore, denitrification is strongly inhibited in pure cultures of denitrifying microorganisms below pH 5. Soils, however, have been shown to denitrify at pH values as low as pH 3. Here we used a continuous bioreactor to investigate the possibility of significant denitrification at low pH under controlled conditions with soil microorganisms and naturally available electron donors. Significant NO₃⁻ and N₂O reduction were observed for 3 months without the addition of any external electron donor. Batch incubations with the enriched biomass showed that low pH as well as low electron donor availability promoted the relative abundance of N₂O as denitrification end-product. Molecular analysis of the enriched biomass revealed that a Rhodanobacter-like bacterium dominated the community in 16S rRNA gene libraries as well as in FISH microscopy during the highest denitrification activity in the reactor. We conclude that denitrification at pH 4 with natural electron donors is possible and that a Rhodanobacter species may be one of the microorganisms involved in acidic denitrification in soils.

  12. Elevation in Tanis expression alters glucose metabolism and insulin sensitivity in H4IIE cells.

    Science.gov (United States)

    Gao, Yuan; Walder, Ken; Sunderland, Terry; Kantham, Lakshmi; Feng, Helen C; Quick, Melissa; Bishara, Natalie; de Silva, Andrea; Augert, Guy; Tenne-Brown, Janette; Collier, Gregory R

    2003-04-01

    Increased hepatic glucose output and decreased glucose utilization are implicated in the development of type 2 diabetes. We previously reported that the expression of a novel gene, Tanis, was upregulated in the liver during fasting in the obese/diabetic animal model Psammomys obesus. Here, we have further studied the protein and its function. Cell fractionation indicated that Tanis was localized in the plasma membrane and microsomes but not in the nucleus, mitochondria, or soluble protein fraction. Consistent with previous gene expression data, hepatic Tanis protein levels increased more significantly in diabetic P. obesus than in nondiabetic controls after fasting. We used a recombinant adenovirus to increase Tanis expression in hepatoma H4IIE cells and investigated its role in metabolism. Tanis overexpression reduced glucose uptake, basal and insulin-stimulated glycogen synthesis, and glycogen content and attenuated the suppression of PEPCK gene expression by insulin, but it did not affect insulin-stimulated insulin receptor phosphorylation or triglyceride synthesis. These results suggest that Tanis may be involved in the regulation of glucose metabolism, and increased expression of Tanis could contribute to insulin resistance in the liver.

  13. [The EHEC O104:H4 outbreak in Germany 2011 - lessons learned?!].

    Science.gov (United States)

    Rissland, J; Kielstein, J T; Stark, K; Wichmann-Schauer, H; Stümpel, F; Pulz, M

    2013-04-01

    The EHEC O104:H4 outbreak 2011 in Germany provided numerous insights into the recognition and control of such epidemic situations. Food-borne outbreaks and their related dynamics may lead to a critical burden of disease and an eventual capacity overload of the medical care system. Possible difficulties in the microbiological diagnostics of new or significantly altered infectious agents may result in a delayed detection of the outbreak as well as the launching of interventional measures. Besides an early notification of the local public health office by the affected institutions, in which a complete electronic procedure and additional sentinel or surveillance instruments (e. g., in emergency departments of hospitals) may be of great help, an interdisciplinary cooperation of the local public health and food safety agencies is the key to an effective outbreak control. Corresponding organizations on the state and federal level should support the investigation process by microbiological diagnostics and advanced epidemiological analysis as well as examination of the food chains. Finally, successful crisis communication relies on "speaking with one voice" (not necessarily one person). Immediate, transparent, appropriate and honest information of the general public concerning the reasons, consequences and (counter-) measures of a crisis are the best means to keep the trust of the population and to counteract the otherwise inevitable speculations.

  14. The Cac1 subunit of histone chaperone CAF-1 organizes CAF-1-H3/H4 architecture and tetramerizes histones

    Science.gov (United States)

    Liu, Wallace H; Roemer, Sarah C; Zhou, Yeyun; Shen, Zih-Jie; Dennehey, Briana K; Balsbaugh, Jeremy L; Liddle, Jennifer C; Nemkov, Travis; Ahn, Natalie G; Hansen, Kirk C; Tyler, Jessica K; Churchill, Mair EA

    2016-01-01

    The histone chaperone Chromatin Assembly Factor 1 (CAF-1) deposits tetrameric (H3/H4)2 histones onto newly-synthesized DNA during DNA replication. To understand the mechanism of the tri-subunit CAF-1 complex in this process, we investigated the protein-protein interactions within the CAF-1-H3/H4 architecture using biophysical and biochemical approaches. Hydrogen/deuterium exchange and chemical cross-linking coupled to mass spectrometry reveal interactions that are essential for CAF-1 function in budding yeast, and importantly indicate that the Cac1 subunit functions as a scaffold within the CAF-1-H3/H4 complex. Cac1 alone not only binds H3/H4 with high affinity, but also promotes histone tetramerization independent of the other subunits. Moreover, we identify a minimal region in the C-terminus of Cac1, including the structured winged helix domain and glutamate/aspartate-rich domain, which is sufficient to induce (H3/H4)2 tetramerization. These findings reveal a key role of Cac1 in histone tetramerization, providing a new model for CAF-1-H3/H4 architecture and function during eukaryotic replication. DOI: http://dx.doi.org/10.7554/eLife.18023.001 PMID:27690308

  15. 组胺H4受体在特应性皮炎发病中的作用%Roles of histamine H4 receptor in the pathogenesis of atopic dermatitis

    Institute of Scientific and Technical Information of China (English)

    张璋; 窦侠; 李建军

    2015-01-01

    组胺是免疫反应中的重要介质,组胺H4受体是近年来新发现的组胺受体,主要表达于免疫器官及细胞上.研究表明,组胺H4受体参与特应性皮炎发病过程中的免疫炎症调节、瘙痒反应及表皮增殖.组胺H4受体的特应性拮抗剂也能影响特应性皮炎的病程发展,通过T细胞、抗原提呈细胞、角质形成细胞等发挥抗炎、调节免疫及其抗瘙痒作用,减轻了特应性皮炎的湿疹样皮炎、顽固性瘙痒的临床症状,有望成为一种新型治疗特应性皮炎的有效手段.%Histamine is an important mediator in inflammatory responses,and histamine H4 receptor is a newly discovered histamine receptor mainly expressed on immune organs and cells.Recent researches have indicated that histamine H4 receptor participates in immunoregulation,pruritus and epidermal proliferation in the pathogenesis of atopic dermatitis.Specific antagonists of histamine H4 receptor can affect the development and attenuate clinical symptoms of atopic dermatitis,such as eczematoid dermatitis and intractable itch,byexerting anti-inflammatory,immunoregulatory and anti-pruritic effects via T-lymphocytes,antigen-presenting cells and keratinocytes.Hence,histamine H4 receptor antagonists are expected to be a novel and effective approach to the treatment of atopic dermatitis.

  16. Cross-species analyses unravel the complexity of H3K27me3 and H4K20me3 in the context of neural stem progenitor cells

    Directory of Open Access Journals (Sweden)

    Christopher T. Rhodes

    2016-06-01

    Full Text Available Neural stem progenitor cells (NSPCs in the human subventricular zone (SVZ potentially contribute to lifelong neurogenesis, yet subtypes of glioblastoma multiforme (GBM contain NSPC signatures that highlight the importance of cell fate regulation. Among numerous regulatory mechanisms, the posttranslational methylations onto histone tails are crucial regulator of cell fate. The work presented here focuses on the role of 2 repressive chromatin marks trimethylations on histone H3 lysine 27 (H3K27me3 and histone H4 lysine 20 (H4K20me3 in the adult NSPC within the SVZ. To best model healthy human NSPCs as they exist in vivo for epigenetic profiling of H3K27me3 and H4K20me3, we used NSPCs isolated from the adult SVZ of baboon brain (Papio anubis with brain structure and genomic level similar to human. The putative role of H3K27me3 in normal NSPCs predominantly falls into the regulation of gene expression, cell cycle, and differentiation, whereas H4K20me3 is involved in DNA replication/repair, metabolism, and cell cycle. Using conditional knockout mouse models to diminish Ezh2 and Suv4-20h responsible for H3K27me3 and H4K20me3, respectively, we found that both repressive marks have irrefutable function for cell cycle regulation in the NSPC population. Although both EZH2/H3K27me3 and Suv4-20h/H4K20me3 have implication in cancers, our comparative genomics approach between healthy NSPCs and human GBM specimens revealed that substantial sets of genes enriched with H3K27me3 and H4K20me3 in the NSPCs are altered in the human GBM. In sum, our integrated analyses across species highlight important roles of H3K27me3 and H4K20me3 in normal and disease conditions in the context of NSPC.

  17. Physical characterization of a suite of Buzzard Coulee H4 chondrite fragments

    Science.gov (United States)

    Fry, C.; Melanson, D.; Samson, C.; McCausland, P. J. A.; Herd, R. K.; Ernst, R. E.; Umoh, J.; Holdsworth, D. W.

    2013-06-01

    On November 20, 2008, the Buzzard Coulee H4 chondrite fell to Earth outside of Lloydminster, Alberta, Canada. Eighteen fresh samples obtained by the National Meteorite Collection of Canada, ranging from 8.80 to 109.14 g, were investigated in this study. Physical properties of the samples were first obtained using a suite of nondestructive techniques. The bulk density (Archimedean bead method: 3.48 ± 0.04 g cm-3; 3-D laser imaging: 3.46 ± 0.03 g cm-3; micro-computed tomography: 3.44 ± 0.03 g cm-3), porosity (6.2 ± 0.1%), bulk magnetic susceptibility (log χ: 5.364 ± 0.056 × 10-9 m3 kg-1 at 825 Hz; 5.329 ± 0.052 × 10-9 m3 kg-1 at 19,000 Hz), and other derived magnetic properties (frequency dependence: 8.7 ± 6.2%; degree of anisotropy A%: 22.0 ± 2.0%; ellipsoid shape B%: -18.7 ± 8.7%) are typical of H chondrites. The coefficient of variation associated with the properties measured directly was low (0.10-1.15%), indicating that the samples are homogenous at the interfragment scale. The study then proceeded with detailed analyses at the intrafragment scale. Visual inspection of micro-computed tomographic images allowed the identification of an anomalous large clast with low metal content in a fragment. Another fragment exhibited macroscopic shock veins that warranted further examination. These fragments were cut and polished thin sections prepared for petrological analysis by optical and scanning electron microscopy. Based on mineralogical and textural similarities with several chondrules, the large clast was interpreted to be a macrochondrule. In a larger context, this study proposes a protocol for the systematic investigation of extraterrestrial material that can be exported to other new meteorite falls and finds, and specimens from sample return mission.

  18. Role of B7-H4 siRNA in Proliferation, Migration, and Invasion of LOVO Colorectal Carcinoma Cell Line

    Directory of Open Access Journals (Sweden)

    Hai-xia Peng

    2015-01-01

    Full Text Available Objectives. Colorectal cancer is one of the most common malignancies. Recent studies investigated that B7-H4 is highly expressed in various cancers. We aimed at exploring the effect of B7-H4 siRNA on proliferation, invasion, and migration of LOVO cells which expressed B7-H4 notably. Design and Methods. Colon adenocarcinoma dataset was downloaded from The Cancer Genome Atlas. 35 colorectal cancer patients admitted to Shanghai Tongren Hospital were enrolled in this study. Cell proliferation and cell cycle distribution were identified by CCK8 and flow cytometry, respectively. Transwell assay was performed to detect the invasion and migration of LOVO cells. CXCL12/CXCR4 expression and JAK2/STAT3 phosphorylation were determined by real-time PCR and western blot. Results. B7-H4 expressed is elevated in colorectal cancer tissues than in the adjacent normal tissues. B7-H4 siRNA effectively inhibited the proliferation at 24 h and 48 h, arrested cell cycle at G0/G1, and suppressed cell invasion and migration. Gene set enrichment analysis showed that CXCL12/CXCR4 and JAK/STAT were correlative with the B7-H4 expression. Additionally, CXCL12/CXCR4 expression and JAK2/STAT3 phosphorylation were reduced. Conclusions. B7-H4 siRNA can effectively inhibit proliferation, invasion, and migration of LOVO cells by targeting CXCL12/CXCR4 and JAK2/STAT3 signaling, which can serve as a new target for colorectal carcinoma treatment.

  19. Impact of histone H4 lysine 20 methylation on 53BP1 responses to chromosomal double strand breaks.

    Directory of Open Access Journals (Sweden)

    Andrea J Hartlerode

    Full Text Available Recruitment of 53BP1 to chromatin flanking double strand breaks (DSBs requires γH2AX/MDC1/RNF8-dependent ubiquitination of chromatin and interaction of 53BP1 with histone H4 methylated on lysine 20 (H4K20me. Several histone methyltransferases have been implicated in 53BP1 recruitment, but their quantitative contributions to the 53BP1 response are unclear. We have developed a multi-photon laser (MPL system to target DSBs to subfemtoliter nuclear volumes and used this to mathematically model DSB response kinetics of MDC1 and of 53BP1. In contrast to MDC1, which revealed first order kinetics, the 53BP1 MPL-DSB response is best fitted by a Gompertz growth function. The 53BP1 MPL response shows the expected dependency on MDC1 and RNF8. We determined the impact of altered H4K20 methylation on 53BP1 MPL response kinetics in mouse embryonic fibroblasts (MEFs lacking key H4K20 histone methyltransferases. This revealed no major requirement for the known H4K20 dimethylases Suv4-20h1 and Suv4-20h2 in 53BP1 recruitment or DSB repair function, but a key role for the H4K20 monomethylase, PR-SET7. The histone methyltransferase MMSET/WHSC1 has recently been implicated in 53BP1 DSB recruitment. We found that WHSC1 homozygous mutant MEFs reveal an alteration in balance of H4K20 methylation patterns; however, 53BP1 DSB responses in these cells appear normal.

  20. 何谓肠出血性大肠杆菌O104:H4及防治%What is enterohemorrhagic Escherichia coli O104:H4 and how to prevent

    Institute of Scientific and Technical Information of China (English)

    任成山; 赵晓晏

    2011-01-01

    @@ 所谓肠出血性大肠杆菌O104:H4(enterohemorrhagic E.coli,O104:H4),是由德国分离的一种新菌珠O104:H4型大肠杆菌,含有志贺毒素2(vtx2a)的基因,没有(enterohemorrhagic Escherichia coli,EHEC)溶血素、志贺毒素1、肠致病性大肠埃希菌(enteropathogenic Escherichia coli)基因毒力岛基因;但含有肠集聚性粘附大肠杆菌(enteroaggragtive Escherichia coli)(第5类致泻性大肠杆菌)毒力质粒上的3个基因:aatA、aggR、aap[1].

  1. 嗜盐古菌Haloferax sp.H4蛋白质表达差异研究%Study on the Protein Ecpression Difference of Halophilic Archaea Haloferax sp.H4

    Institute of Scientific and Technical Information of China (English)

    刘杰; 高凯; 陈晨; 陈绍兴

    2011-01-01

    [目的]研究嗜盐古菌Haloferax sp.H4在不同环境中的蛋白表达差异.[方法]采用变性聚丙烯酰胺凝胶电泳(SDS-PAGE)检测不同NaCl浓度、pH、温度、有氧和无氧条件下的H4菌株蛋白表达差异.[结果]H4菌株在不同NaCl浓度、有氧和无氧条件下的蛋白表达存在明显特异性;而在不同pH和温度条件下,其蛋白表这差异性不明显.[结论]嗜盐古菌对不同环境因子的调控方式可能存在差异.%[Objective]The research aimed to study the protein expression difference of halophilic archaea Haloferax sp.H4 under the different environments.[Method]SDS-PAGE was used to detect the porotein expression difference of H4strain under the different NaCl concentration,PH value,temperature,aerobic and anaerobic conditions.[Result]The protein expression of H4strain had the obvious specificity underthe different NaCl concentration,aerobic and anaerobic conditions.But under the different pH value and temperature conditions,the protein expression different wasn't obvious.[Conclusion]Maybe the regulation manner of halophilic arehaea on the different environmental factors had the difference.

  2. Quantification of B7-H4 with real-time fluorescent PCR and its preliminary application in gastric carcinoma%B7-H4实时荧光定量PCR检测方法的建立及其在人胃癌组织中的初步应用

    Institute of Scientific and Technical Information of China (English)

    王琦; 蒋敬庭; 魏文祥

    2013-01-01

    Objective To establish a real-time fluorescent polymerase chain reaction for quantifying B7-H4 and detect the expression of B7-H4 in human gastric carcinoma.Methods The B7-H4 and internal reference gene GAPDH fragments in correct sequence from RT-PCR were cloned into pMD19-T vector,and recombinant plasmids were purified and quantified by spectrophotometry.Standard curves was established by using a serial dilution of quantified plasmids in order to measure B7-H4 and GAPDH.Real-time fluorescent PCR was used to quantify the expression level of B7-H4 relative to GAPDH in 8 gastric carcinoma tissues.Results For B7-H4,the detection of the minimum copy number was 5.27 copies.The linear range of 5.27 × 101 ~ 5.27 × 107 copies of the standard curve equation (y =-3.1395 x + 41.805) was found and the correlation coefficient for 0.994 904 was obtained.The inter-assay CV ranged from 2.39% to 3.59% and the amplification efficiency was 108.2%.For GAPDH,the detection of the minimum copy number was 38.6 copies.The linear range of 3.86 × 102 to 3.86 × 107 copies of the standard curve equation (y =-3.2436 x + 41.083) was found and the correlation coefficient of 0.998 913 was obtained.The inter-assay CV ranged from 2.26% to 3.86% and the amplification efficiency was 103.4%.mRNA levels of B7-H4 relative to GAPDH in 8 gastric carcinoma tissues were between 0.044 and 0.888.Conclusion The real-time fluorescent quantitative PCR system established for quantifying B7-H4 is rapid,specific,sensitive and accurate.The standard system is repeatable and has a good linear range.%目的 建立实时荧光定量PCR检测B7-H4的方法并初步应用于人胃癌组织.方法 将B7-H4和内参GAPDH的PCR扩增产物经测序鉴定正确后克隆入载体pMD19-T,构建重组质粒标准品,并纯化、定量及梯度稀释,分别建立B7-H4和GAPDH的标准曲线,应用实时荧光定量PCR检测8例人胃癌组织中的B7-H4相对于GAPDH的表达情况.结果 B7-H4

  3. Poisson Lie symmetry and D-branes in WZW model on the Heisenberg Lie group $H_4$

    CERN Document Server

    Eghbali, A

    2015-01-01

    We show that the WZW model on the Heisenberg Lie group $H_4$ has Poisson-Lie symmetry only when the dual Lie group is ${ A}_2 \\oplus 2{ A}_1$. In this way, we construct the mutual T-dual sigma models on Drinfel'd double generated by the Heisenberg Lie group $H_4$ and its dual pair, ${ A}_2 \\oplus 2{ A}_1$, as the target space in such a way that the original model is the same as the $H_4$ WZW model. Furthermore, we show that the dual model is conformal up to two loops order. Finally, we discuss $D$-branes and the worldsheet boundary conditions defined by a gluing matrix on the $H_4$ WZW model. Using the duality map obtained from the canonical transformation description of the Poisson-Lie T-duality transformations for the gluing matrix which locally defines the properties of the $D$-brane, we find two different cases of the gluing matrices for the WZW model based on the Heisenberg Lie group $H_4$ and its dual model.

  4. Poisson Lie symmetry and D-branes in WZW model on the Heisenberg Lie group H4

    Directory of Open Access Journals (Sweden)

    A. Eghbali

    2015-10-01

    Full Text Available We show that the WZW model on the Heisenberg Lie group H4 has Poisson–Lie symmetry only when the dual Lie group is A2⊕2A1. In this way, we construct the mutual T-dual sigma models on Drinfel'd double generated by the Heisenberg Lie group H4 and its dual pair, A2⊕2A1, as the target space in such a way that the original model is the same as the H4 WZW model. Furthermore, we show that the dual model is conformal up to two-loop order. Finally, we discuss D-branes and the worldsheet boundary conditions defined by a gluing matrix on the H4 WZW model. Using the duality map obtained from the canonical transformation description of the Poisson–Lie T-duality transformations for the gluing matrix which locally defines the properties of the D-brane, we find two different cases of the gluing matrices for the WZW model based on the Heisenberg Lie group H4 and its dual model.

  5. An H3-H4 histone gene pair in the marine copepod Tigriopus californicus, contains an intergenic dyad symmetry element.

    Science.gov (United States)

    Porter, D; Brown, D; Wells, D

    1991-01-01

    Histone genes are one of the most widely studied multigene families in eucaryotes. Over 200 histone genes have been sequenced, primarily in vertebrates, echinoderms, fungi and plants. We present here the structure and genomic orientation of an H3-H4 histone gene pair from the marine copepod, Tigriopus californicus. These histone gene sequences are the first to be determined for the class Crustacea and among the first to be determined for protostomes. The H4 and H3 genes in Tigriopus are shown to be adjacent, to have opposite polarity, and to contain a 26 bp region of dyad symmetry centrally located within the spacer region between the two genes. A similarly located dyad element has been found in yeast which contributes to the coordinated cell cycle control of the adjacent histone genes. The Tigriopus H3-H4 histone gene pair is clustered with one H2A and two H2B histone genes on a 15 kb genomic Bam H1 fragment. The H4 gene sequence predicts an H4 protein with an unusual serine to threonine substitution at the amino terminal residue. The H3 gene sequence predicts an H3 protein which is identical to the vertebrate H3.2 histone.

  6. Low Temperature Deposition of PECVD Polycrystalline Silicon Thin Films using SiF4 / SiH4 mixture

    Science.gov (United States)

    Syed, Moniruzzaman; Inokuma, Takao; Kurata, Yoshihiro; Hasegawa, Seiichi

    2016-03-01

    Polycrystalline silicon films with a strong (110) texture were prepared at 400°C by a plasma-enhanced chemical vapor deposition using different SiF4 flow rates ([SiF4] = 0-0.5 sccm) under a fixed SiH4 flow rate ([SiH4] = 1 or 0.15 sccm). The effects of the addition of SiF4 to SiH4 on the structural properties of the films were studied by Raman scattering, X-ray diffraction (XRD), Atomic force microscopy and stress measurements. For [SiH4] = 1 sccm, the crystallinity and the (110) XRD grain size monotonically increased with increasing [SiF4] and their respective maxima reach 90% and 900 Å. However, for [SiH4] = 0.15 sccm, both the crystallinity and the grain size decreased with [SiF4]. Mechanisms causing the change in crystallinity are discussed, and it was suggested that an improvement in the crystallinity, due to the addition of SiF4, is likely to be caused by the effect of a change in the surface morphology of the substrates along with the effect of in situ chemical cleaning.

  7. N2H4·H2O水热体系ZnO微晶的结晶特性%ZnO microcrystal growth in hydrothermal processing with N2H4·H2O

    Institute of Scientific and Technical Information of China (English)

    刘长友; 谷智; 王涛; 查钢强; 介万奇

    2011-01-01

    研究了低浓度(0.01~0.20mol/L)N2H4.H2O条件下ZnO微晶的低温水热结晶特性。N2H4.H2O弱碱性和N2H5+吸附配位性影响ZnO微晶的形核和各晶面的生长速率。随着N2H4.H2O浓度的提高,ZnO微晶分别呈板条状、六角片状和六角棒束状。碱性分散剂和超声的分散作用影响主要在成核阶段;受分散剂弱碱性的影响,0.20mol/L N2H4.H2O显现出强的还原性,N2气泡模板生长机制使所制ZnO微晶呈六角管状晶须束。%ZnO microcrystal growth was investigated under a low temperature hydrothermal process with a relatively low concentration of N2H4·H2O(0.01-0.20mol/L).The nucleation and the growth rates of various crystal planes are strongly affected by the weak alkalinity of N2H4·H2O and the co-ordinative activity of N2H+5 ion.ZnO microcrystals change from oatmeal-like plate to hexagonal plate,and then to hexagonal rod-like cluster with increasing of N2H4·H2O concentrations,respectively.The nucleations of ZnO microcrystals are influenced by the alkaline dispersant and ultrasonic treatment.The solution of 0.20mol/L N2H4·H2O with the alkaline dispersant has a strong reducibility,which changes the mechanism of nucleation and growth of ZnO microcrystals.The center-hollow hexagonal rod-like ZnO clusters were obtained through the N2 bubble template-growth route.

  8. H4octapa: highly stable complexation of lanthanide(III) ions and copper(II).

    Science.gov (United States)

    Kálmán, Ferenc Krisztián; Végh, Andrea; Regueiro-Figueroa, Martín; Tóth, Éva; Platas-Iglesias, Carlos; Tircsó, Gyula

    2015-03-02

    The acyclic ligand octapa(4-) (H4octapa = 6,6'-((ethane-1,2-diylbis((carboxymethyl)azanediyl))bis(methylene))dipicolinic acid) forms stable complexes with the Ln(3+) ions in aqueous solution. The stability constants determined for the complexes with La(3+), Gd(3+), and Lu(3+) using relaxometric methods are log KLaL = 20.13(7), log KGdL = 20.23(4), and log KLuL = 20.49(5) (I = 0.15 M NaCl). High stability constants were also determined for the complexes formed with divalent metal ions such as Zn(2+) and Cu(2+) (log KZnL = 18.91(3) and log KCuL = 22.08(2)). UV-visible and NMR spectroscopic studies and density functional theory (DFT) calculations point to hexadentate binding of the ligand to Zn(2+) and Cu(2+), the donor atoms of the acetate groups of the ligand remaining uncoordinated. The complexes formed with the Ln(3+) ions are nine-coordinated thanks to the octadentate binding of the ligand and the presence of a coordinated water molecule. The stability constants of the complexes formed with the Ln(3+) ions do not change significantly across the lanthanide series. A DFT investigation shows that this is the result of a subtle balance between the increased binding energies across the 4f period, which contribute to an increasing complex stability, and the parallel increase of the absolute values of the hydration free energies of the Ln(3+) ions. In the case of the [Ln(octapa)(H2O)](-) complexes the interaction between the amine nitrogen atoms of the ligand and the Ln(3+) ions is weakened along the lanthanide series, and therefore the increased electrostatic interaction does not overcome the increasing hydration energies. A detailed kinetic study of the dissociation of the [Gd(octapa)(H2O)](-) complex in the presence of Cu(2+) shows that the metal-assisted pathway is the main responsible for complex dissociation at pH 7.4 and physiological [Cu(2+)] concentration (1 μM).

  9. Kaolinite dissolution and precipitation kinetics at 22oC and pH4

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Li; Steefel, Carl I.

    2007-07-16

    Dissolution and precipitation rates of low defect Georgia kaolinite (KGa-1b) as a function of Gibbs free energy of reaction (or reaction affinity) were measured at 22 C and pH 4 in continuously stirred flow through reactors. Steady state dissolution experiments showed slightly incongruent dissolution, with a Si/Al ratio of about 1.12 that is attributed to the re-adsorption of Al on to the kaolinite surface. No inhibition of the kaolinite dissolution rate was apparent when dissolved aluminum was varied from 0 and 60 {micro}M. The relationship between dissolution rates and the reaction affinity can be described well by a Transition State Theory (TST) rate formulation with a Temkin coefficient of 2 R{sub diss} (mol/m{sup 2}s) = 1.15 x 10{sup -13} [1-exp(-{Delta}G/2RT)]. Stopping of flow in a close to equilibrium dissolution experiment yielded at solubility constant for kaolinite at 22 C of 10{sup 7.57}. Experiments on the precipitation kinetics of kaolinite showed a more complex behavior. One conducted using kaolinite seed that had previously undergone extensive dissolution under far from equilibrium conditions for 5 months showed a quasi-steady state precipitation rate for 105 hours that was compatible with the TST expression above. After this initial period, however, precipitation rates decreased by an order of magnitude, and like other precipitation experiments conducted at higher supersaturation and without kaolinite seed subjected to extensive prior dissolution, could not be described with the TST law. The initial quasi-steady state rate is interpreted as growth on activated sites created by the dissolution process, but this reversible growth mechanism could not be maintained once these sites were filled. Long-term precipitation rates showed a linear dependence on solution saturation state that is generally consistent with a two dimensional nucleation growth mechanism following the equation R{sub ppt}(mol/m{sup 2}s) = 3.38 x 10{sup -14} exp[181776/T{sup 2}1n

  10. Identification and pharmacological characterization of a series of new 1H-4-substituted-imidazoyl histamine H3 receptor ligands.

    Science.gov (United States)

    Yates, S L; Phillips, J G; Gregory, R; Pawlowski, G P; Fadnis, L; Khan, M A; Ali, S M; Tedford, C E

    1999-05-01

    A new series of 1H-4-substituted imidazole compounds were synthesized and identified as potent and selective histamine (HA) H3 receptor ligands. These ligands establish that HA H3 antagonists exhibit stereoselective and conformational preferences in their binding to the HA H3 receptor. Structure-activity relationships were determined in vitro by HA H3 receptor-binding affinities using [3H]Nalpha-methylhistamine and rat cerebral cortical tissue homogenates. Several derivatives containing olefin, amide, and acetylene functional groups were identified as potent HA H3 receptor ligands. In the olefin series, GT-2227 (4-(6-cyclohexylhex-cis-3-enyl)imidazole) was identified as a potent HA H3 receptor ligand with a Ki of 4.2 +/- 0.6 nM, while the trans isomer (GT-2228) displayed a reduced potency (Ki = 15.2 +/- 2.4 nM). GT-2227 was also found to have excellent central nervous system penetration in an ex vivo binding paradigm (ED50 = 0.7 mg/kg i.p.). In the acetylene series, GT-2260 and GT-2286 both exhibited high affinity (Ki = 2.9 +/- 0.2 and 0.95 +/- 0.3 nM) and excellent central nervous system penetration profiles (ED50 = 0.43 and 0.48 mg/kg i.p., respectively). As a prototype for the series, GT-2227 showed high affinity for the human HA H3 receptor (3.2 nM) and minimal affinity for the human HA H1 (Ki = 13,407 +/- 540 nM) and H2 (Ki = 4,469 +/- 564 nM) receptor subtypes. GT-2227 also showed good selectivity for the HA H3 receptor over a broad spectrum of other neurotransmitter receptors (IC50 >/= 1 microM). Furthermore, GT-2227 improved acquisition in a cognitive paradigm without behavioral excitation or effect on spontaneous locomotor activity. In summary, the present studies demonstrate the development of novel HA H3-selective ligands, and lend support for the use of such agents in the treatment of disorders associated with cognitive or attentional deficits.

  11. Catalytic synthesis of cyclohexanone 1,2-propanediol ketal with H4SiW12O40/Pan

    Institute of Scientific and Technical Information of China (English)

    YANG Shuijin; YU Xieqing; SUN Jutang

    2004-01-01

    A new environmental friendly catalyst, H4SiW12O40/PAn was prepared and identified by means of FT-IR, XRD and TG/DTA. Cyclohexanone 1,2-propanediol ketal was synthesized from cyclohexanone and 1,2-propanediol in the presence of H4SiW12O40/PAn. The factors influencing the synthesis were discussed and the best conditions were found out. The optimum conditions are: molar ratio of cyclohexanone to 1,2-propanediol is 1:1.4, the quantity of catalyst is equal to 1.0%of feed stocks, and the reaction time is 40 min. H4SiW12O40/PAn is an excellent catalyst for synthesizing cyclohexanone 1,2-propanediol ketal and its yield can reach over 96.5%.

  12. Detection of NO sub x,C2H4 concentrations by using CO and CO2 lasers

    Science.gov (United States)

    Gengchen, W.; Qinxin, K.

    1986-01-01

    A laser, especially the infrared line tunable laser, opens up a new way to monitor the atmospheric environment, and already has gotten effective practical application. One of the most serious problems in open path remote measurement at atmospheric pressure is the broadening effect which leads to increased linewidths, spectral interferences, and, as a result, tends to reduce detection sensitivity, so measuring laser wavelengths should be selected carefully, and interaction between the measuring wavelength and gas to be measured must be known very well. Therefore, N2O, No, NO2, CH4, NH3 and C2H4 absorption properties at some lines of CO and CO2 line tunable lasers were studied. The absorption coefficients of NO, NO2, and C2H4; some results on detection of NO sub x, C2H4 concentrations in both laboratory and field; and selection of measuring wavelengths and error analysis are discussed.

  13. Alignment-free design of highly discriminatory diagnostic primer sets for Escherichia coli O104:H4 outbreak strains.

    Science.gov (United States)

    Pritchard, Leighton; Holden, Nicola J; Bielaszewska, Martina; Karch, Helge; Toth, Ian K

    2012-01-01

    An Escherichia coli O104:H4 outbreak in Germany in summer 2011 caused 53 deaths, over 4000 individual infections across Europe, and considerable economic, social and political impact. This outbreak was the first in a position to exploit rapid, benchtop high-throughput sequencing (HTS) technologies and crowdsourced data analysis early in its investigation, establishing a new paradigm for rapid response to disease threats. We describe a novel strategy for design of diagnostic PCR primers that exploited this rapid draft bacterial genome sequencing to distinguish between E. coli O104:H4 outbreak isolates and other pathogenic E. coli isolates, including the historical hæmolytic uræmic syndrome (HUSEC) E. coli HUSEC041 O104:H4 strain, which possesses the same serotype as the outbreak isolates. Primers were designed using a novel alignment-free strategy against eleven draft whole genome assemblies of E. coli O104:H4 German outbreak isolates from the E. coli O104:H4 Genome Analysis Crowd-Sourcing Consortium website, and a negative sequence set containing 69 E. coli chromosome and plasmid sequences from public databases. Validation in vitro against 21 'positive' E. coli O104:H4 outbreak and 32 'negative' non-outbreak EHEC isolates indicated that individual primer sets exhibited 100% sensitivity for outbreak isolates, with false positive rates of between 9% and 22%. A minimal combination of two primers discriminated between outbreak and non-outbreak E. coli isolates with 100% sensitivity and 100% specificity. Draft genomes of isolates of disease outbreak bacteria enable high throughput primer design and enhanced diagnostic performance in comparison to traditional molecular assays. Future outbreak investigations will be able to harness HTS rapidly to generate draft genome sequences and diagnostic primer sets, greatly facilitating epidemiology and clinical diagnostics. We expect that high throughput primer design strategies will enable faster, more precise responses to

  14. Chemical abundances in the extremely carbon-rich and xenon-rich halo planetary nebula H4-1

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Masaaki [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Tajitsu, Akito, E-mail: otsuka@asiaa.sinica.edu.tw, E-mail: tajitsu@subaru.naoj.org [Subaru Telescope, NAOJ, 650 North A' ohoku Place, Hilo, HI 96720 (United States)

    2013-12-01

    We performed detailed chemical abundance analysis of the extremely metal-poor ([Ar/H] ∼ –2) halo planetary nebula (PN) H4-1 based on the multi-wavelength spectra from Subaru/HDS, GALEX, SDSS, and Spitzer/IRS and determined the abundances of 10 elements. The C and O abundances were derived from collisionally excited lines (CELs) and are almost consistent with abundances from recombination lines (RLs). We demonstrated that the large discrepancy in the C abundance between CEL and RL in H4-1 can be solved using the temperature fluctuation model. We reported the first detection of the [Xe III] λ5846 line in H4-1 and determination of its elemental abundance ([Xe/H] > +0.48). H4-1 is the most Xe-rich PN among the Xe-detected PNe. The observed abundances are close to the theoretical prediction by a 2.0 M {sub ☉} single star model with an initially element rich ([r/Fe] = +2.0 dex) rapid neutron-capture process (r-process). The observed Xe abundance would be a product of the r-process in primordial supernovae. The [C/O]-[Ba/(Eu or Xe)] diagram suggests that the progenitor of H4-1 shares the evolution with carbon-enhanced metal-poor (CEMP)-r/s and CEMP-no stars. The progenitor of H4-1 is presumably a binary formed in an r-process-rich environment.

  15. The H4IIE cell bioassay as an indicator of dioxin-like chemicals in wildlife and the environment.

    Science.gov (United States)

    Whyte, J J; Schmitt, C J; Tillitt, D E

    2004-01-01

    The H4IIE cell bioassay has proven utility as a screening tool for planar halogenated hydrocarbons (PHHs) and structurally similar chemicals accumulated in organisms from the wild. This bioassay has additional applications in hazard assessment of PHH exposed populations. In this review, the toxicological principles, current protocols, performance criteria, and field applications for the assay are described. The H4IIE cell bioassay has several advantages over the analytical measurement of PHHs in environmental samples, but conclusions from studies can be strengthened when both bioassay and analytical chemistry data are presented together. Often, the bioassay results concur with biological effects in organisms and support direct measures of PHHs. For biomonitoring purposes and prioritization of PHH-contaminated environments, the H4IIE bioassay may be faster and less expensive than analytical measurements. The H4IIE cell bioassay can be used in combination with other biomarkers such as in vivo measurements of CYP1A1 induction to help pinpoint the sources and identities of dioxin-like chemicals. The number of studies that measure H4IIE-derived TCDD-EQs continues to increase, resulting in subtle improvements over time. Further experiments are required to determine if TCDD-EQs derived from mammalian cells are adequate predictors of toxicity to non-mammalian species. The H4IIE cell bioassay has been used in over 300 published studies, and its combination of speed, simplicity, and ability to integrate the effects of complex contaminant mixtures makes it a valuable addition to hazard assessment and biomonitoring studies.

  16. B7-H4-Ig treatment of normal mice changes lymphocyte homeostasis and increases the potential of regulatory T cells.

    Science.gov (United States)

    Kristensen, Nanna N; Schmidt, Esben G W; Rasmussen, Susanne; Balk-Møller, Emilie; Claesson, Mogens H

    2013-08-01

    Enteroantigens (eAgs) drive tolerogenic and inflammatory immune responses in the gut and are of importance for sustained immune homeostasis in colonic mucosa. Decline of regulatory activity in the gut mucosa might result in chronic colitis. B7-H4 is a co-inhibitory receptor expressed by professional antigen-presenting cells. By delivering signal 2 during T cell activation, it inhibits T cell proliferation and inflammation. In this study, we have used a newly developed B7-H4-Ig fusion protein and evaluated its effect on eAg-activated effector and regulatory T cells (Treg) in vitro and in vivo. T cells were recovered from the mesenteric lymph nodes (MLNs) of untreated or B7-H4-Ig-treated BALB/c mice. Treatment of cells in vitro did neither affect the proliferation of effector T cells nor the function of Tregs. In vivo, B7-H4 treatment increased the total number of MLN-derived CD4⁺ and CD8⁺ T cell subsets as well as the functional activity of MLN-derived Tregs, whereas the proliferative activity of eAg or alloantigen specific effector T cells was not influenced, although treatment resulted in less secretion of inflammatory cytokines and chemokines from these cells. B7-H4-Ig treatment of severe combined immune-deficient (SCID) mice undergoing T cell transfer colitis did not influence the course of disease probably reflecting the lack of Tregs in this model of chronic colitis. In conclusion, we show that treatment with B7-H4-Ig in vivo changes lymphocyte homeostasis and increases the regulatory potential in normal mice, but does not affect the course of disease development in SCID mice undergoing T cell transfer colitis.

  17. Amorphous Silicon Film Deposition from SiH4 by Chemical Vapor Deposition with Argon Excimer Lamp

    Science.gov (United States)

    Toshikawa, Kiyohiko; Yokotani, Atsushi; Kurosawa, Kou

    2005-11-01

    We have deposited amorphous silicon thin films from monosilane (SiH4) gas by photochemical vapor deposition using a vacuum ultraviolet excimer lamp (VUV-CVD). We used an argon excimer lamp (λ=126 nm, hν=9.8 eV) whose photons are strongly absorbed by SiH4 gas. The substrate temperatures were changed from 25 to 300°C. When the temperature was lower than 150°C, the films included H--Si--H units and H2 molecules in its structure. When it was higher than 150°C, the main structural unit was Si--H.

  18. Reversible hydrogen storage by NaAlH4 confined within a titanium-functionalized MOF-74(Mg) nanoreactor.

    Science.gov (United States)

    Stavila, Vitalie; Bhakta, Raghunandan K; Alam, Todd M; Majzoub, Eric H; Allendorf, Mark D

    2012-11-27

    We demonstrate that NaAlH(4) confined within the nanopores of a titanium-functionalized metal-organic framework (MOF) template MOF-74(Mg) can reversibly store hydrogen with minimal loss of capacity. Hydride-infiltrated samples were synthesized by melt infiltration, achieving loadings up to 21 wt %. MOF-74(Mg) possesses one-dimensional, 12 Å channels lined with Mg atoms having open coordination sites, which can serve as sites for Ti catalyst stabilization. MOF-74(Mg) is stable under repeated hydrogen desorption and hydride regeneration cycles, allowing it to serve as a "nanoreactor". Confining NaAlH(4) within these pores alters the decomposition pathway by eliminating the stable intermediate Na(3)AlH(6) phase observed during bulk decomposition and proceeding directly to NaH, Al, and H(2), in agreement with theory. The onset of hydrogen desorption for both Ti-doped and undoped nano-NaAlH(4)@MOF-74(Mg) is ∼50 °C, nearly 100 °C lower than bulk NaAlH(4). However, the presence of titanium is not necessary for this increase in desorption kinetics but enables rehydriding to be almost fully reversible. Isothermal kinetic studies indicate that the activation energy for H(2) desorption is reduced from 79.5 kJ mol(-1) in bulk Ti-doped NaAlH(4) to 57.4 kJ mol(-1) for nanoconfined NaAlH(4). The structural properties of nano-NaAlH(4)@MOF-74(Mg) were probed using (23)Na and (27)Al solid-state MAS NMR, which indicates that the hydride is not decomposed during infiltration and that Al is present as tetrahedral AlH(4)(-) anions prior to desorption and as Al metal after desorption. Because of the highly ordered MOF structure and monodisperse pore dimensions, our results allow key template features to be identified to ensure reversible, low-temperature hydrogen storage.

  19. Oxidation Of Cyclohexane To Cyclohexanol And Cyclohexanone Using H4[α-SiW12O40]/Zr As Catalyst

    Directory of Open Access Journals (Sweden)

    Aldes Lesbani

    2016-05-01

    Full Text Available Synthesis and preparation of polyoxometalate H4[α-SiW12O40].nH2O with Zr as support at various weights of Zr 0.01g; 0.05 g; 0.25 g; 0.5 g; 0.75 g; 1 g and 1.25 g to form H4[α- SiW12O40]/Zr was conducted. The compounds from preparation were characterized using FTIR spectroscopy and crystallinity analysis using X-Ray diffraction. Thus H4[α- SiW12O40]/Zr was applied as catalyst for oxidation of cyclohexane to cyclohexanol and cyclohexanone. Oxidation process was studied through reaction time, hydrogen peroxide amount, temperature, and weight of catalyst. FTIR spectrum of H4[α-SiW12O40]/Zr was appeared at wavenumber 771.53-979.84 cm-1 and Zr at 486.06-1481.33 cm-1. Diffraction pattern of H4[α-SiW12O40]/Zr showed that high crystallinity was identified at 2θ 8o-10o and 28.3o. Based on FTIR spectrum and XRD powder pattern, the optimum preparation of H4[α-SiW12O40]/Zr was obtained using 0.5 g of Zr. The catalytic study of cyclohexane using H4[α-SiW12O40]/Zr at 0.5 g of Zr resulted conversion about 99.73%. Catalyst can convert cyclohexane with the highest conversion then used for further deep catalytic investigation. Optimization of oxidation process resulted optimum reaction time at 2 h, 3 mL of hydrogen peroxide amount, 80 oC of temperature, and 0.038 g of catalyst. The GCMS analysis indicated the oxidation of cyclohexane using H4[α-SiW12O40]/Zr at 0.5 g of Zr formed cyclohexanol and cyclohexanone with selectivity 18.77 and 23.57, respectively.

  20. Macro-, Micro-, Nano- and Crystal Structures of a Homodinuclear Complex [NH3(CH2)3NH3]2{Na2[(C6H4O2)2](C6H4O2H)2}

    Institute of Scientific and Technical Information of China (English)

    LU,Xiao-Ming; WEI,Chun-Xia; WANG,Zhen; YE,Chao-Hui

    2007-01-01

    A homodinuclear complex (NH3CH2CH2CH2NH3)2{Na2[(C6H4O2)2](C6H4O2H)2} (1) has been synthesized by a solution-based self-assembly route. It crystallized in monoclinic system with space group P21/c. Every sodium ion coordinates in a tetragonal prism fashion with two O atoms of a terminal chelating catecholate ligand and three O atoms from two bridging catecholate ligands. Two neighboring NaO5 tetragonal prisms are edge-shared and centrosymmetric with regard to the inversion center to form a binuclear cluster {Na2[(C6H4O2)2](C6H4OOH)2}4- anion.The complex anions were aligned parallelly by π-π interaction and linked with the protonated 1,3-propylenediamine through hydrogen bonds which were assembled into a multi-lamellar structure with channels. The crystal exhibits rectangular geometry with an interior triangle hollow structure under optical microscopy. And the scanning electron microscopy (SEM) indicates that the wall of the tubes shows multi-lamella morphologies. Further, the transmission electron microscopy (TEM) reveals that the crystal is composed of multi-lamellar nano-tubes with diameters less than 100 nm. The molecular structure of the complex was compared with that of its isomer complex 2.

  1. SUMO-1 Promotes Ishikawa Cell Proliferation and Apoptosis in Endometrial Cancer by Increasing Sumoylation of Histone H4.

    Science.gov (United States)

    Zheng, Jindan; Liu, Lili; Wang, Shanfeng; Huang, Xin

    2015-10-01

    To investigate the functional role of SUMO-1 on cell proliferation and apoptosis in endometrial cancer cells (Ishikawa line) and to explore the underlying regulatory mechanisms. Different concentrations of estradiol (E2) and small interfering RNA (siRNA) targeting the SUMO-1 (siCo) were treated in Ishikawa cells, and then quantitative polymerase chain reaction was used to examine the expression of progesterone receptor (PR) expression in Ishikawa cells. Western blots were applied to validate histone H4 sumoylation. CCK8 assay and flow cytometry were performed to investigate cell proliferation and apoptosis in Ishikawa cells. Estradiol up-regulated the expression of PR messenger RNA, most obviously at 100 nM. SUMO-1 siRNA decreased the PR expression. Estradiol up-regulated H4 sumoylation and caused the increase of Ishikawa cell proliferation, whereas SUMO-1 siRNA down-regulated H4 sumoylation, inhibited the cell proliferation, and induced apoptosis. Furthermore, SUMO-1 siRNA-transfected cells were arrested in the S and G2/M phases and E2 increased the S and G2/M phases of Ishikawa cells. SUMO-1 regulates the Ishikawa cell proliferation and apoptosis by the sumoylation of histone H4.

  2. Enhancement of the hydrogen storage capacity of Mg(AlH4)2 by excess electrons: a DFT study.

    Science.gov (United States)

    Kang, Sunwoo; Karthikeyan, S; Lee, Jin Yong

    2013-01-28

    The enhancement of hydrogen storage in complexes of magnesium alanate ([Mg(AlH(4))(2)](n)(-) where n = 2, 3) and their anions was investigated using the B3LYP/6-311++G** method. Hydrogen atoms were chemically absorbed on [Mg(AlH(4))(2)](n)(-) (n = 2, 3) with binding energies of -83 to -91.23 kcal mol(-1). It was determined that a maximum of two hydrogen atoms can be absorbed on [Mg(AlH(4))(2)](n)(-) (n = 2, 3) complexes at 10.51 and 10.21 wt%, respectively. Natural bond order analysis revealed that, in the absence of hydrogen, the excess electron population lies predominantly along the sigma bonds between Mg(2+) atoms, while, upon absorption of the hydrogen atoms, the excess electron population lies on the absorbed hydrogen atoms. The vertical detachment energy showed that the excess electron is strongly bound to [Mg(AlH(4))(2)](n)(-) (n = 2, 3) complexes with energies of 78 to 153 kcal mol(-1). It can be seen from the stabilization energy values that the stability of hydrogen-absorbed complexes with excess electrons was significantly enhanced.

  3. Electron energy distribution function in capacitively coupled RF discharges: difference between electropositive Ar and electronegative SiH4 discharges

    NARCIS (Netherlands)

    Yan, M.; Bogaerts, A.; W. J. Goedheer,; Gijbels, R.

    2000-01-01

    The electron energy distribution functions (EEDFs) for electropositive Ar and electronegative SiH4 discharges have been studied by means of a one-dimensional particle-in-cell/Monte Carlo (1D PIC/MC) model and have been compared under the same discharge conditions (frequency, power and pressure). The

  4. First line shape analysis and spectroscopic parameters for the ν11 band of 12C2H4

    KAUST Repository

    Es-sebbar, Et-touhami

    2016-08-11

    An accurate knowledge of line intensities, collisional broadening coefficients and narrowing parameters is necessary for the interpretation of high-resolution infrared spectra of the Earth and other planetary atmospheres. One of the most promising spectral domains for (C2H4)-C-12 monitoring in such environments is located near the 336 gm window, through its v(11) C-H stretching mode. In this paper, we report an extensive study in which we precisely determine spectroscopic parameters of (C2H4)-C-12 v(11) band at 297 +/- 1 K, using a narrow Difference-Frequency-Generation (DFG) laser with 10(-4) cm(-1) resolution. Absorption measurements were performed in the 2975-2980 cm(-1) spectral window to investigate 32 lines corresponding to where, J\\'ka\\',kc\\'<- Jka,kc, 5 <= J <= 7; 0.5 <= K-a <= 6 and 1 <= K-c <= 14. Spectroscopic parameters are retrieved using either Voigt or appropriate Galatry profile to simulate the measured (C2H4)-C-12 line shape. Line intensities along with self-broadening coefficients are reported for all lines. Narrowing coefficients for each isolated line are also derived. To our knowledge, the current study reports the first extensive spectroscopic parameter measurements of the (C2H4)-C-12 v(11) band in the 2975-2980 cm(-1) range. (C) 2016 Elsevier Ltd. All rights reserved.

  5. Gradient nature shaping of the 20X2H4A steel structure as a carbonitriding result

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ The study of the shaping of the gradient structure nature appearing in constructional alloy martensite 20X2H4A steel (0.2%C, 2%Cr, 4%Ni), as a result of surface saturation by carbon and nitrogen (carbonitriding) at 920℃ in industrial conditions is made in present work by methods of optical and transmission electron microscopy.

  6. Histone H4R3 methylation catalyzed by SKB1/PRMT5 is required for maintaining shoot apical meristem.

    Directory of Open Access Journals (Sweden)

    Minghui Yue

    Full Text Available The shoot apical meristem (SAM is the source of all of the above-ground tissues and organs in post-embryonic development in higher plants. Studies have proven that the expression of genes constituting the WUSCHEL (WUS-CLAVATA (CLV feedback loop is critical for the SAM maintenance. Several histone lysine acetylation and methylation markers have been proven to regulate the transcription level of WUS. However, little is known about how histone arginine methylation regulates the expression of WUS and other genes. Here, we report that H4R3 symmetric dimethylation (H4R3sme2 mediated by SKB1/PRMT5 represses the expression of CORYNE (CRN to maintain normal SAM geometrics. SKB1 lesion results in small SAM size in Arabidopsis, as well as down-regulated expression of WUS and CLV3. Up-regulation of WUS expression enlarges SAM size in skb1 mutant plants. We find that SKB1 and H4R3sme2 associate with the chromatin of the CRN locus to down-regulate its transcription. Mutation of CRN rescues the expression of WUS and the small SAM size of skb1. Thus, SKB1 and SKB1-mediated H4R3sme2 are required for the maintenance of SAM in Arabidopsis seedlings.

  7. Chemical abundances in the extremely Carbon and Xenon-rich halo planetary nebula H4-1

    CERN Document Server

    Otsuka, Masaaki

    2013-01-01

    We performed detailed chemical abundance analysis of the extremely metal-poor ([Ar/H]-2) halo planetary nebula H4-1 based on the multi-wavelength spectra from Subaru/HDS, GALEX, SDSS, and Spitzer/IRS and determined the abundances of 10 elements. The C and O abundances were derived from collisionally excited lines (CELs) and are almost consistent with abundances from recombination lines (RLs). We demonstrated that the large discrepancy in the C abundance between CEL and RL in H4-1 can be solved using the temperature fluctuation model. We reported the first detection of the [Xe III]5846 A line in H4-1 and determination of its elemental abundance ([Xe/H]>+0.48). H4-1 is the most Xe-rich PN among the Xe-detected PNe. The observed abundances are close to the theoretical prediction by a ~2.0 Msun single star model with initially r-process element rich ([r/Fe]=+2.0 dex). The observed Xe abundance would be a product of the r-process in primordial SNe. The [C/O]-[Ba/(Eu or Xe)] diagram suggests that the progenitor of ...

  8. B7-H4-Ig treatment of normal mice changes lymphocyte homeostasis and increases the potential of regulatory T cells

    DEFF Research Database (Denmark)

    Kristensen, Nanna N; Schmidt, Esben G W; Rasmussen, Susanne

    2013-01-01

    Enteroantigens (eAgs) drive tolerogenic and inflammatory immune responses in the gut and are of importance for sustained immune homeostasis in colonic mucosa. Decline of regulatory activity in the gut mucosa might result in chronic colitis. B7-H4 is a co-inhibitory receptor expressed by professio......Enteroantigens (eAgs) drive tolerogenic and inflammatory immune responses in the gut and are of importance for sustained immune homeostasis in colonic mucosa. Decline of regulatory activity in the gut mucosa might result in chronic colitis. B7-H4 is a co-inhibitory receptor expressed...... by professional antigen-presenting cells. By delivering signal 2 during T cell activation, it inhibits T cell proliferation and inflammation. In this study, we have used a newly developed B7-H4-Ig fusion protein and evaluated its effect on eAg-activated effector and regulatory T cells (Treg) in vitro and in vivo......⁺ T cell subsets as well as the functional activity of MLN-derived Tregs, whereas the proliferative activity of eAg or alloantigen specific effector T cells was not influenced, although treatment resulted in less secretion of inflammatory cytokines and chemokines from these cells. B7-H4-Ig treatment...

  9. Gradient nature shaping of the 20X2H4A steel structure as a carbonitriding result

    Institute of Scientific and Technical Information of China (English)

    Kozlov; E.; V.; Malinovskaya; V.; A.; Popova; N.; A.

    2005-01-01

    The study of the shaping of the gradient structure nature appearing in constructional alloy martensite 20X2H4A steel (0.2%C, 2%Cr, 4%Ni), as a result of surface saturation by carbon and nitrogen (carbonitriding) at 920℃ in industrial conditions is made in present work by methods of optical and transmission electron microscopy.……

  10. The H4 subunit of vaccinia virus RNA polymerase is not required for transcription initiation at a viral late promoter.

    OpenAIRE

    Wright, C F; Coroneos, A M

    1995-01-01

    Chromatography of RNA polymerase purified from vaccinia virions and from vaccinia virus-infected HeLa cells resulted in the separation of populations active for early and late transcription. An RNA polymerase population immunodepleted for the vaccinia virus H4 gene peptide could support late transcription.

  11. 中度嗜盐菌H4的分离鉴定及硝酸盐还原能力分析%Isolation and identification of mesohalophilic archaea H4 and analysis of the ability of nitrate reduction

    Institute of Scientific and Technical Information of China (English)

    陈绍兴; 唐红斌; 杨权芬; 李沁; 陈娅; 苏嵘; 马自成; 谢志雄

    2011-01-01

    A species of genus Haloferxa that grows under strict anaerobic conditions in the dark and requires Mg2+ , with strong nitrate reduction ability, was isolated from Eastern salt, one of the largest salt fields in Hainan Province, by the enrichment culture medium.Some morphological observations on this halobacteria showed that colonies were orange, moist and round; Physiological and biochemical characteristics suggested that the optimal temperature for grow was 38~40 ℃ and the optimal salinity at 12 %and pH levels at 6.5~7.5.H4 could survive and grow under conditions of the lactose, galactose and ribose as a sole carbon source, and proline and alanine as a sole nitrogen source.A phylogenetic tree of halophilic archaea Halofera H4 was constructed by MEGA 4.0, based on the 16S rDNA sequence analysis.Thus, we could identify it as genus of Haloferax and named Haloferax sp.H4.Furthermore,the qualitative and quantitative analysis of the reduction ability had been conducted.%本研究采用嗜盐丰富培养基,通过富集培养的方法,从海南岛的东方盐场中分离到一株硝酸盐还原能力较强的嗜盐古菌菌株H4;形态观察结果显示,菌落呈橙红色、湿润、圆形,生理生化特征鉴定结果显示,其最适生长的盐浓度、pH值、温度分别为12%、6.5~7.5、38~40℃,并且生长需要Mg2+;能够厌氧生长;乳糖、半乳糖和核糖可以作为其生长的唯一碳源,脯氨酸和丙氨酸可以作为唯一氨源,采用MEGA4.0软件,并结合16SrDNA序列,进行系统发育树分析,确定H4菌株属于Haloferax属,并命名为Haloferaxsp.H4.进一步对其硝酸盐还原能力进行定性和定量研究.

  12. Stabilization of 3d Transition Metal Hydrido Complexes in SrH2Mg2[Co(I)H5], BaH2Mg5[Co(-I)H4]2, and RbH2Mg5[Co(-I)H4 Ni(0)H4] via Easily Polarizable Hydride Ligands.

    Science.gov (United States)

    Fahlquist, Henrik; Moser, David; Noréus, Dag; Refson, Keith; Parker, Stewart F

    2016-04-04

    A combined study using neutron diffraction, inelastic neutron scattering, and first-principles calculations describe cobalt with a very low formal oxidation state of (-I) in a slightly distorted tetrahedral Co(-I)H4-complex in BaH2Mg5[Co(-I)H4]2 and in the structurally related RbH2Mg5[Co(-I)H4 Ni(0)H4]. This indicates that the electron "back donating" effect via the polarizable hydride ions to the counterions in the solid state hydrides, can be compared to more conventional "back bonding" able to reduce the oxidation state down to -I. The hydrides were synthesized by hot sintering of transition metal powders with corresponding binary alkali- and alkaline earth hydrides. In the similarly synthesized SrH2Mg2[Co(I)H5], cobalt is formally + I-valent, showing a high sensitivity to differences in the counterion framework, which can also influence electrical properties.

  13. Alignment-free design of highly discriminatory diagnostic primer sets for Escherichia coli O104:H4 outbreak strains.

    Directory of Open Access Journals (Sweden)

    Leighton Pritchard

    Full Text Available BACKGROUND: An Escherichia coli O104:H4 outbreak in Germany in summer 2011 caused 53 deaths, over 4000 individual infections across Europe, and considerable economic, social and political impact. This outbreak was the first in a position to exploit rapid, benchtop high-throughput sequencing (HTS technologies and crowdsourced data analysis early in its investigation, establishing a new paradigm for rapid response to disease threats. We describe a novel strategy for design of diagnostic PCR primers that exploited this rapid draft bacterial genome sequencing to distinguish between E. coli O104:H4 outbreak isolates and other pathogenic E. coli isolates, including the historical hæmolytic uræmic syndrome (HUSEC E. coli HUSEC041 O104:H4 strain, which possesses the same serotype as the outbreak isolates. METHODOLOGY/PRINCIPAL FINDINGS: Primers were designed using a novel alignment-free strategy against eleven draft whole genome assemblies of E. coli O104:H4 German outbreak isolates from the E. coli O104:H4 Genome Analysis Crowd-Sourcing Consortium website, and a negative sequence set containing 69 E. coli chromosome and plasmid sequences from public databases. Validation in vitro against 21 'positive' E. coli O104:H4 outbreak and 32 'negative' non-outbreak EHEC isolates indicated that individual primer sets exhibited 100% sensitivity for outbreak isolates, with false positive rates of between 9% and 22%. A minimal combination of two primers discriminated between outbreak and non-outbreak E. coli isolates with 100% sensitivity and 100% specificity. CONCLUSIONS/SIGNIFICANCE: Draft genomes of isolates of disease outbreak bacteria enable high throughput primer design and enhanced diagnostic performance in comparison to traditional molecular assays. Future outbreak investigations will be able to harness HTS rapidly to generate draft genome sequences and diagnostic primer sets, greatly facilitating epidemiology and clinical diagnostics. We expect that high

  14. The C terminus of the histone chaperone Asf1 cross-links to histone H3 in yeast and promotes interaction with histones H3 and H4.

    Science.gov (United States)

    Dennehey, Briana K; Noone, Seth; Liu, Wallace H; Smith, Luke; Churchill, Mair E A; Tyler, Jessica K

    2013-02-01

    The central histone H3/H4 chaperone Asf1 comprises a highly conserved globular core and a divergent C-terminal tail. While the function and structure of the Asf1 core are well known, the function of the tail is less well understood. Here, we have explored the role of the yeast (yAsf1) and human (hAsf1a and hAsf1b) Asf1 tails in Saccharomyces cerevisiae. We show, using a photoreactive, unnatural amino acid, that Asf1 tail residue 210 cross-links to histone H3 in vivo and, further, that loss of C-terminal tail residues 211 to 279 weakens yAsf1-histone binding affinity in vitro nearly 200-fold. Via several yAsf1 C-terminal truncations and yeast-human chimeric proteins, we found that truncations at residue 210 increase transcriptional silencing and that the hAsf1a tail partially substitutes for full-length yAsf1 with respect to silencing but that full-length hAsf1b is a better overall substitute for full-length yAsf1. In addition, we show that the C-terminal tail of Asf1 is phosphorylated at T270 in yeast. Loss of this phosphorylation site does not prevent coimmunoprecipitation of yAsf1 and Rad53 from yeast extracts, whereas amino acid residue substitutions at the Asf1-histone H3/H4 interface do. Finally, we show that residue substitutions in yAsf1 near the CAF-1/HIRA interface also influence yAsf1's function in silencing.

  15. The histone chaperones Nap1 and Vps75 bind histones H3 and H4 in a tetrameric conformation.

    Science.gov (United States)

    Bowman, Andrew; Ward, Richard; Wiechens, Nicola; Singh, Vijender; El-Mkami, Hassane; Norman, David George; Owen-Hughes, Tom

    2011-02-18

    Histone chaperones physically interact with histones to direct proper assembly and disassembly of nucleosomes regulating diverse nuclear processes such as DNA replication, promoter remodeling, transcription elongation, DNA damage, and histone variant exchange. Currently, the best-characterized chaperone-histone interaction is that between the ubiquitous chaperone Asf1 and a dimer of H3 and H4. Nucleosome assembly proteins (Nap proteins) represent a distinct class of histone chaperone. Using pulsed electron double resonance (PELDOR) measurements and protein crosslinking, we show that two members of this class, Nap1 and Vps75, bind histones in the tetrameric conformation also observed when they are sequestered within the nucleosome. Furthermore, H3 and H4 trapped in their tetrameric state can be used as substrates in nucleosome assembly and chaperone-mediated lysine acetylation. This alternate mode of histone interaction provides a potential means of maintaining the integrity of the histone tetramer during cycles of nucleosome reassembly.

  16. Fuel performance improvement program: description and characterization of HBWR Series H-2, H-3, and H-4 test rods

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, R.J.; Barner, J.O.; Welty, R.K.

    1980-03-01

    The fabrication process and as-built characteristics of the HBWR Series H-2 and H-3 test rods, as well as the three packed-particle (sphere-pac) rods in HBWR Series H-4 are described. The HBWR Series H-2, H-3, and H-4 tests are part of the irradiation test program of the Fuel Performance Improvement Program. Fifteen rods were fabricated for the three test series. Rod designs include: (1) a reference dished pellet design incorporating chamfered edges, (2) a chamfered, annular pellet design combined with graphite-coated cladding, and (3) a sphere-pac design. Both the annular-coated and sphere-pac designs include internal pressurization using helium.

  17. Plasma-catalytic Selective Reduction of NO with C2H4 in the Presence of Excess Oxygen

    Institute of Scientific and Technical Information of China (English)

    Qi SUN; Ai Min ZHU; Xue Feng YANG; Jin Hai NIU; Yong XU; Zhi Min SONG; Jing LIU

    2005-01-01

    This paper reports observations of significant synergistic effects between dielectric barrier discharge (DBD) plasmas and Cu-ZSM-5 catalysts for C2H4 selective reduction of NOx at250 ℃ in the presence of excess oxygen by using a one-stage plasma-over-catalyst (POC) reactor.With the reactant gas mixture of 530 ppm NO, 650 ppm C2H4, 5.8% O2 in N2and GHSV = 12000h-1, the pure catalytic, pure plasma-induced (discharges over fused silica pellets) and plasmacatalytic (in the POC reactor) NOx conversion are 39%, 1.5% and 79%, respectively. The in-situ optical emission spectra of the reactive systems imply some short-lived active species formed from plasma-induced and plasma-catalytic processes may be responsible to the observed synergistic effects in this one-stage POC system.

  18. Molecular dynamics simulations demonstrate the regulation of DNA-DNA attraction by H4 histone tail acetylations and mutations.

    Science.gov (United States)

    Korolev, Nikolay; Yu, Hang; Lyubartsev, Alexander P; Nordenskiöld, Lars

    2014-10-01

    The positively charged N-terminal histone tails play a crucial role in chromatin compaction and are important modulators of DNA transcription, recombination, and repair. The detailed mechanism of the interaction of histone tails with DNA remains elusive. To model the unspecific interaction of histone tails with DNA, all-atom molecular dynamics (MD) simulations were carried out for systems of four DNA 22-mers in the presence of 20 or 16 short fragments of the H4 histone tail (variations of the 16-23 a. a. KRHRKVLR sequence, as well as the unmodified fragment a. a.13-20, GGAKRHRK). This setup with high DNA concentration, explicit presence of DNA-DNA contacts, presence of unstructured cationic peptides (histone tails) and K(+) mimics the conditions of eukaryotic chromatin. A detailed account of the DNA interactions with the histone tail fragments, K(+) and water is presented. Furthermore, DNA structure and dynamics and its interplay with the histone tail fragments binding are analysed. The charged side chains of the lysines and arginines play major roles in the tail-mediated DNA-DNA attraction by forming bridges and by coordinating to the phosphate groups and to the electronegative sites in the minor groove. Binding of all species to DNA is dynamic. The structure of the unmodified fully-charged H4 16-23 a.a. fragment KRHRKVLR is dominated by a stretched conformation. The H4 tail a. a. fragment GGAKRHRK as well as the H4 Lys16 acetylated fragment are highly flexible. The present work allows capturing typical features of the histone tail-counterion-DNA structure, interaction and dynamics.

  19. The impact of solubility and electrostatics on fibril formation by the H3 and H4 histones.

    Science.gov (United States)

    Topping, Traci B; Gloss, Lisa M

    2011-12-01

    The goal of this study was to examine fibril formation by the heterodimeric eukaryotic histones (H2A-H2B and H3-H4) and homodimeric archaeal histones (hMfB and hPyA1). The histone fold dimerization motif is an obligatorily domain-swapped structure comprised of two fused helix:β-loop:helix motifs. Domain swapping has been proposed as a mechanism for the evolution of protein oligomers as well as a means to form precursors in the formation of amyloid-like fibrils. Despite sharing a common fold, the eukaryotic histones of the core nucleosome and archaeal histones fold by kinetic mechanisms of differing complexity with transient population of partially folded monomeric and/or dimeric species. No relationship was apparent between fibrillation propensity and equilibrium stability or population of kinetic intermediates. Only H3 and H4, as isolated monomers and as a heterodimer, readily formed fibrils at room temperature, and this propensity correlates with the significantly lower solubility of these polypeptides. The fibrils were characterized by ThT fluorescence, FTIR, and far-UV CD spectroscopies and electron microscopy. The helical histone fold comprises the protease-resistant core of the fibrils, with little or no protease protection of the poorly structured N-terminal tails. The highly charged tails inhibit fibrillation through electrostatic repulsion. Kinetic studies indicate that H3 and H4 form a co-fibril, with simultaneous incorporation of both histones. The potential impact of H3 and H4 fibrillation on the cytotoxicity of extracellular histones and α-synuclein-mediated neurotoxicity and fibrillation is considered. Copyright © 2011 The Protein Society.

  20. Kinetic study on the H + SiH4 abstraction reaction using an ab initio potential energy surface.

    Science.gov (United States)

    Cao, Jianwei; Zhang, Zhijun; Zhang, Chunfang; Bian, Wensheng; Guo, Yin

    2011-01-14

    Variational transition state theory calculations with the correction of multidimensional tunneling are performed on a 12-dimensional ab initio potential energy surface for the H + SiH(4) abstraction reaction. The surface is constructed using a dual-level strategy. For the temperature range 200-1600 K, thermal rate constants are calculated and kinetic isotope effects for various isotopic species of the title reaction are investigated. The results are in very good agreement with available experimental data.

  1. Improved Hydrogen Storage Properties of Mg(BH4)2-Mg(AlH4)2 Combined Systems

    Science.gov (United States)

    Xiao, Haoyuan; Leng, Haiyan; Yu, Zhigang; Li, Qian; Chou, Kuo-Chih

    Magnesium borohydride and Magnesium alanate were synthesized by mechanochemical metathesis reaction. The thermal decomposition behaviors of Mg(BH4)2-nMg(AlH4)2(n=0.5,1) systems were investigated as potential hydrogen storage materials. The results showed that the systems started to desorb H2 at 120 °C and desorbed 3.9 wt.% and 4.9 wt.% H2 below 300 °C when n equals 0.5 and 1, respectively, while individual Mg(BH4)2 started to desorb H2 at 250 °C and desorbed only 0.82 wt.% H2. Because of the exist of the Mg(AlH4)2, the isothermal desorption kinetics of Mg(BH4)2 in the Mg(BH4)2-0.5Mg(AlH4)2 systems was 50% faster than that of pristine Mg(BH4)2. In addition, the re-hydrogenation rates also increased 49.4% and 37.9%.

  2. The MOF chromobarrel domain controls genome-wide H4K16 acetylation and spreading of the MSL complex.

    Science.gov (United States)

    Conrad, Thomas; Cavalli, Florence M G; Holz, Herbert; Hallacli, Erinc; Kind, Jop; Ilik, Ibrahim; Vaquerizas, Juan M; Luscombe, Nicholas M; Akhtar, Asifa

    2012-03-13

    The histone H4 lysine 16 (H4K16)-specific acetyltransferase MOF is part of two distinct complexes involved in X chromosome dosage compensation and autosomal transcription regulation. Here we show that the MOF chromobarrel domain is essential for H4K16 acetylation throughout the Drosophila genome and is required for spreading of the male-specific lethal (MSL) complex on the X chromosome. The MOF chromobarrel domain directly interacts with nucleic acids and potentiates MOF's enzymatic activity after chromatin binding, making it a unique example of a chromo-like domain directly controlling acetylation activity in vivo. We also show that the Drosophila-specific N terminus of MOF has evolved to perform sex-specific functions. It modulates nucleosome binding and HAT activity and controls MSL complex assembly, thus regulating MOF function in dosage compensation. We propose that MOF has been especially tailored to achieve tight regulation of its enzymatic activity and enable its dual role on X and autosomes.

  3. Laser photoacoustic trace detection of C2H4 revealing adverse environmental effects of atmospheric pollution on plant material

    Science.gov (United States)

    Harren, Frans J. M.; Petruzzelli, Luciana

    1993-03-01

    The photoacoustic detection method for trace gases in the atmosphere is well developed towards very low limits of detection, in the last years. Due to the combination of a sensitive photoacoustic cell placed intracavity in an infrared CO2 laser we were able to detect C2H4 at ultralow (hormone which seems to play an important role throughout all the life stages of a plant, including seed germination. In addition, various types of stress have been reported to promote ethylene production from different plant tissues. As part of our ongoing research on the role of ethylene in seed germination, we have compared our laser photoacoustic set-up to a gaschromatograph for measuring C2H4 produced by germinating Pisum sativum L. seeds within the first days of imbibition. C2H4 evolution by intact seeds shows a maximum at about 25 hours of germination. Thereafter, the rate of ethylene measured by gaschromatograph continues to decrease while that measured by the laser-driven photoacoustic system shows further increases. Most of the ethylene produced by seeds is found in isolated embryonic axes. The fumigation with ozone affects the growth of seedlings and their ethylene evolution.

  4. A nucleosome-like structure containing DNA and the arginine-rich histones H3 and H4.

    Science.gov (United States)

    Moss, T; Stephens, R M; Crane-Robinson, C; Bradbury, E M

    1977-07-01

    The low-angle X-ray diffraction pattern from fibres of reconstituted H3/H4/DNA complexes is very similar to that of chromatin and has well defined maxima at 10.6, 5.4, 3.4 and 2.6 nm. Staphyloccal nuclease digestion of reconstituted H3/H4/DNA yields DNA fragments of length 49, 69, 100, 128, 193 and 255 b.p. as principal components. Comparison of the relative amounts of DNA fragments shows that the larger components (100 and 128 b.p.) increase with respect to the smaller (49 and 69 b.p.) as the histone to DNA ratio increases. A structural unit containing intergral of 65 b.p. of DNA and tetrameric (H3/H4)2 is proposed such that longer DNA fragments result from multiples of this unit. The principal nucleo-protein particle resulting from nuclease digestion contains 128/139 b.p. of DNA and has electrophoretic mobility very close to that of 'core' nucleosome. It probably represents a dimer of the basic structural unit.

  5. Effects of antibiotics on Shiga toxin 2 production and bacteriophage induction by epidemic Escherichia coli O104:H4 strain.

    Science.gov (United States)

    Bielaszewska, Martina; Idelevich, Evgeny A; Zhang, Wenlan; Bauwens, Andreas; Schaumburg, Frieder; Mellmann, Alexander; Peters, Georg; Karch, Helge

    2012-06-01

    The role of antibiotics in treatment of enterohemorrhagic Escherichia coli (EHEC) infections is controversial because of concerns about triggering hemolytic-uremic syndrome (HUS) by increasing Shiga toxin (Stx) production. During the recent large EHEC O104:H4 outbreak, antibiotic therapy was indicated for some patients. We tested a diverse panel of antibiotics to which the outbreak strain is susceptible to interrogate the effects of subinhibitory antibiotic concentrations on induction of stx(2)-harboring bacteriophages, stx(2) transcription, and Stx2 production in this emerging pathogen. Ciprofloxacin significantly increased stx(2)-harboring phage induction and Stx2 production in outbreak isolates (P values of 0.1) and chloramphenicol, meropenem, azithromycin, rifaximin, and tigecycline significantly decreased them (P ≤ 0.05). Ciprofloxacin and chloramphenicol significantly upregulated and downregulated stx(2) transcription, respectively (P antibiotics had insignificant effects (P > 0.1). Meropenem, azithromycin, and rifaximin, which were used for necessary therapeutic or prophylactic interventions during the EHEC O104:H4 outbreak, as well as tigecycline, neither induced stx(2)-harboring phages nor increased stx(2) transcription or Stx2 production in the outbreak strain. These antibiotics might represent therapeutic options for patients with EHEC O104:H4 infection if antibiotic treatment is inevitable. We await further analysis of the epidemic to determine if usage of these agents was associated with an altered risk of developing HUS.

  6. Xbp1-mediated histone H4 deacetylation contributes to DNA double-strand break repair in yeast

    Institute of Scientific and Technical Information of China (English)

    Ran Tao; Hua Chen; Chan Gao; Pcng Xue; Fuquan Yang; Jing-Dong J Han; Bing Zhou; Ye-Guang Chen

    2011-01-01

    Xbp1 has been shown to regulate the cell cycle as a transcriptional repressor in budding yeast Saccharomyces cerevisiae.In this study,we demonstrated that Xbp1 regulates DNA double-strand break (DSB) repair in S.cerevisiae.Xbp1 physically and genetically interacts with the histone deacetylase Rpd3 complex.Chromatin immunoprecipitation revealed that Xbp1 is required for efficient deacetylation of histone H4 flanking DSBs by the Rpd3 complex.Deletion of XBP1 leads to the delayed deacetylation of histone H4,which is coupled with increased nucleosome displacement,increased DNA end resection and decreased non-homologous end-joining (NHEJ).In response to DNA damage,Xbp1 is upregulated in a Mec1-Rad9-Rad53 checkpoint pathway-dependent manner and undergoes dephosphorylation.Cdk1,a central regulator of S.cerevisiae cell cycle,is responsible for Xbp1 phosphorylation at residues Ser146,Ser271 and Ser551.Substitution of these serine residues with alanine not only increases the association of Xbp1 with the Rpd3 complex and its recruitment to a DSB,but also promotes DSB repair.Together,our findings reveal a role for Xbp1 in DSB repair via NHEJ through regulation of histone H4 acetylation and nucleosome displacement in a positive feedback manner.

  7. Chromatin-modifying complex component Nurf55/p55 associates with histones H3 and H4 and polycomb repressive complex 2 subunit Su(z)12 through partially overlapping binding sites.

    Science.gov (United States)

    Nowak, Agnieszka J; Alfieri, Claudio; Stirnimann, Christian U; Rybin, Vladimir; Baudin, Florence; Ly-Hartig, Nga; Lindner, Doris; Müller, Christoph W

    2011-07-01

    Drosophila Nurf55 is a component of different chromatin-modifying complexes, including the PRC2 (Polycomb repressive complex 2). Based on the 1.75-Å crystal structure of Nurf55 bound to histone H4 helix 1, we analyzed interactions of Nurf55 (Nurf55 or p55 in fly and RbAp48/46 in human) with the N-terminal tail of histone H3, the first helix of histone H4, and an N-terminal fragment of the PRC2 subunit Su(z)12 using isothermal calorimetry and pulldown experiments. Site-directed mutagenesis identified the binding site of histone H3 at the top of the Nurf55 WD40 propeller. Unmodified or K9me3- or K27me3-containing H3 peptides were bound with similar affinities, whereas the affinity for K4me3-containing H3 peptides was reduced. Helix 1 of histone H4 and Su(z)12 bound to the edge of the β-propeller using overlapping binding sites. Our results show similarities in the recognition of histone H4 and Su(z)12 and identify Nurf55 as a versatile interactor that simultaneously contacts multiple partners.

  8. B7-H4 gene polymorphisms are associated with sporadic breast cancer in a Chinese Han population

    Directory of Open Access Journals (Sweden)

    Fu Zhenkun

    2009-11-01

    Full Text Available Abstract Background B7-H4, a co-inhibitory molecule of the B7 family, can restrain T cell proliferation, cytokine secretion and the development of cytotoxicity. B7-H4 is expressed in tumor tissues at a higher level than in normal tissues, and has a potential effect to protect tumors from anti-tumor immune responses. This case-control study was carried out to determine the potential influences of B7-H4 gene polymorphisms on the susceptibility and progression of breast cancer in Han women of Northeast China. Methods We genotyped three B7-H4 variants (rs10754339, rs10801935 and rs3738414 and tagged all common haplotypes (frequency greater than or equal to 1% in a Chinese population consisting of 500 breast cancer cases and 504 control individuals matched for age. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP technique was used to determine the genotypes. Results Our data indicated that, compared with the common genotype and allele of each SNP, the rs10754339 AG genotype and G allele showed a significantly increased risk of breast cancer (OR = 1.455, 95% CI 1.119-1.892; OR = 1.325, 95% CI 1.073-1.637, respectively. The rs10801935 CC genotype, the rs3738414 AA genotype and the rs3738414 A allele were associated with a significantly decreased risk of breast cancer (OR = 0.328, 95% CI 0.145-0.739; OR = 0.412, 95% CI 0.203-0.835; OR = 0.698, 95% CI 0.564-0.864, respectively. Additionally, the rs10754339 GG genotype was significantly associated with lymph node metastasis and PR status, and the G allele and the AG genotype were respectively associated with lymph node metastasis and ER status. In haplotype analysis, we observed that compared with the AAG haplotype, the AAA haplotype showed a significantly decreased risk of breast cancer (OR = 0.689, 95% CI 0.539-0.881, but the GAG haplotype was associated with a significantly increased risk of breast cancer (OR = 1.511, 95% CI 1.125-2.031. And the AAA and the GCG haplotypes

  9. Laboratory Studies on the Formation of Three C2H4O Isomers-Acetaldehyde (CH3CHO), Ethylene Oxide (c-C2H4O), and Vinyl Alcohol (CH2CHOH)-in Interstellar and Cometary Ices

    Science.gov (United States)

    Bennett, Chris J.; Osamura, Yoshihiro; Lebar, Matt D.; Kaiser, Ralf I.

    2005-11-01

    Laboratory experiments were conducted to unravel synthetic routes to form three C2H4O isomers-acetaldehyde (CH3CHO), ethylene oxide (c-C2H4O), and vinyl alcohol (CH2CHOH)-in extraterrestrial ices via electronic energy transfer processes initiated by electrons in the track of MeV ion trajectories. Here we present the results of electron irradiation on a 2:1 mixture of carbon dioxide (CO2) and ethylene (C2H4). Our studies suggest that suprathermal oxygen atoms can add to the carbon-carbon π bond of an ethylene molecule to form initially an oxirene diradical (addition to one carbon atom) and the cyclic ethylene oxide molecule (addition to two carbon atoms) at 10 K. The oxirene diradical can undergo a [1, 2]-H shift to the acetaldehyde molecule. Both the ethylene oxide and the acetaldehyde isomers can be stabilized in the surrounding ice matrix. To a minor amount, suprathermal oxygen atoms can insert into a carbon-hydrogen bond of the ethylene molecule, forming vinyl alcohol. Once these isomers have been synthesized inside the ice layers of the coated grains in cold molecular clouds, the newly formed molecules can sublime as the cloud reaches the hot molecular core stage. These laboratory investigations help to explain astronomical observations by Nummelin et al. and Ikeda et al. toward massive star-forming regions and hot cores, where observed fractional abundances of these isomers are higher than can be accounted for by gas-phase reactions alone. Similar synthetic routes could help explain the formation of acetaldehyde and ethylene oxide in comet C/1995 O1 (Hale-Bopp) and also suggest a presence of both isomers in Titan's atmosphere.

  10. Hydrogen Desorption Performance of Ti-Mediated MgH2 and Mg2NiH4%Ti掺杂的MgH2和Mg2NiH4的放氢性能

    Institute of Scientific and Technical Information of China (English)

    周广有; 郑时有; 方方; 张晶; 徐芬; 孙立贤; 陈国荣; 孙大林

    2008-01-01

    以TiF3和Ti(OBu-n)4为催化剂,研究了Ti离子掺杂对MgH2和Mg2NiH4放氢性能的影响.结果表明,未掺杂的MgH2起始放氢温度为420℃,掺杂TiF3和Ti(OBu-n)4后分别降低到360和410℃;Mg2NiH4在掺杂TiF3后放氢温度由230℃降低到220℃,而掺杂Ti(OBu-n)4后没有变化.可见无论对MgH2或Mg2NiH4,在降低放氢温度方面TiF3都明显优于Ti(OBu-n)4.另外,研究还发现,TiF3掺杂对MgH2放氢动力学有显著的提高,但对Mg2NiH4没有明显的提高.结合XRD和FHR的测试分析,我们认为:催化作用很大程度上取决于氢化物自身的晶体结构和催化剂的电子结构;降低氢化物放氢温度和提高动力学性能的原因是催化剂与氢化物之间的相互作用削弱了氢化物中Mg-H或Ni-H键,使得活泼的H…H原子对容易形成,从而有利于H2的释出.

  11. The tumor suppressor SirT2 regulates cell cycle progression and genome stability by modulating the mitotic deposition of H4K20 methylation

    Science.gov (United States)

    The establishment of the epigenetic mark H4K20me1 (monomethylation of H4K20) by PR-Set7 during G2/M directly impacts S-phase progression and genome stability. However, the mechanisms involved in the regulation of this event are not well understood. Here we show that SirT2 regulates H4K20me1 depositi...

  12. Dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans via fish consumption and dioxin-like activity in fish determined by H4IIE-luc bioassay.

    Science.gov (United States)

    Chan, Janet Kit Yan; Man, Yu Bon; Xing, Guan Hua; Wu, Sheng Chun; Murphy, Margaret B; Xu, Ying; Wong, Ming H

    2013-10-01

    Dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) via fish consumption in two major electronic (e) waste sites: Guiyu (GY), Guangdong Province and Taizhou (TZ), Zhejiang Province, and dioxin-like activity in fish determined by H4IIE-luc bioassay. In the present study, all fish were below EU's maximum allowable concentration in muscle of fish (4 pg WHO-TEQ/g wet wt), except crucian (4.28 pg WHO-TEQ/g wet wt) and silver carps (7.49 pg WHO-TEQ/g wet wt) collected from GY rivers. Moreover, the residual concentration in bighead carp collected from GY (2.15 pg WHO-TEQ/g wet wt) was close to the EU's action level (3 pg WHO-TEQ/g wet wt) which gives "early warning" to the competent authorities and operators to take measures to eliminate contamination. In addition, results indicated that the maximum human intake of PCDD/Fs via freshwater fish consumption in GY was 4.31 pg WHO-TEQ/kg bw/day, which exceeds the higher end of the tolerable daily intake recommended by the WHO, EC-SCF and JECFA (1-4, 2 and 2.3 pg WHO-TEQ/kg bw/day respectively). Furthermore, H4IIE-luc cell bioassay provides a very sensitive and cost-efficient screening tool for assessing the overall dioxin-like toxicity in the study, and is therefore valuable for high-throughput environmental monitoring studies. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Magnetic properties of PrCo 2 and its ternary hydride PrCo 2H 4

    Science.gov (United States)

    de Jongh, L. J.; Bartolomé, J.; Greidanus, F. J. A. M.; de Groot, H. J. M.; Stipdonk, H. L.; Buschow, K. H. J.

    1981-12-01

    Magnetization and susceptibility data on PrCo 2 and PrCo 2H 4 are presented. The ac susceptibility of PrCo 2 measured in zero dc field displays a sharp and high peak at Tc = (39.9 ± 0.2) K. The magnetization versus temperature curves show ferromagnetic behaviour for B >1 T, but display a maximum at lower values of the applied field. These results, together with the behaviour of the hysteresis loops at different temperatures below Tc, indicate that PrCo 2 orders ferromagnetically, the magnetic hardness increasing strongly for T → 0. The saturation moment at 4.2 K equals 3.9 μ B per formula unit, as found from the magnetization curve measured in a pulsed-field magnet up to B = 30 T. Similar experiments on PrCo 2H 4 provide evidence that the introduction of hydrogen in PrCo 2 not only destroys the long-range atomic order, but also considerably reduces the ferromagnetic interactions. Such an effect of the hydrogen is commonly observed in cobalt intermetallics. Part of the PrCo 2H 4 is found to have decomposed into PrH 2 and free Co. The clusters of free Co atoms give rise to a maximum in the zero-field ac susceptibility versus temperature curves, similar as observed in spin glasses or magnetic glasses. By increasing the ac frequency, the maximum shifts to higher temperatures. The behavior can be explained in terms of the Néel model for superparamagnetic particles with randomly oriented local anisotropy axes.

  14. Theoretical analysis of resonance states in $^{4}H$, $^{4}He$ and $^{4}Li$ above three-cluster threshold

    CERN Document Server

    Vasilevsky, V; Broeckhove, J; Romanov, V N

    2004-01-01

    The resonance states of $^{4}H$, $^{4}He$ and $^{4}Li$, embedded in the three-cluster $d+N+N$ continuum, are investigated within a three-cluster model. The model treats the Pauli principle exactly and incorporates the Faddeev components for proper description of the boundary conditions for the two- and three-body continua. The hyperspherical harmonics are used to distinguish and numerate channels of the three-cluster continuum. It is shown that the effective barrier, created by three-cluster configuration $d+N+N$, is strong enough to accommodate two resonance states.

  15. Investigation of histone H4 hyperacetylation dynamics in the 5S rRNA genes family by chromatin immunoprecipitation assay.

    Science.gov (United States)

    Burlibașa, Liliana; Suciu, Ilinca

    2015-12-01

    Oogenesis is a critical event in the formation of female gamete, whose role in development is to transfer genomic information to the next generation. During this process, the gene expression pattern changes dramatically concomitant with genome remodelling, while genomic information is stably maintained. The aim of the present study was to investigate the presence of H4 acetylation of the oocyte and somatic 5S rRNA genes in Triturus cristatus, using chromatin immunoprecipitation assay (ChIP). Our findings suggest that some epigenetic mechanisms such as histone acetylation could be involved in the transcriptional regulation of 5S rRNA gene families.

  16. Copper CMP Modeling: Millisecond Scale Adsorption Kinetics of BTA in Glycine-Containing Solutions at pH 4

    OpenAIRE

    Choi, Seungchoun; Tripathi, Shantanu; Dornfeld, David; Doyle, F M

    2010-01-01

    Millisecond scale benzotriazole (BTA) adsorption kinetics in acidic aqueous solution containing 0.01 M glycine and 0.01 M BTA have been investigated. Chronoamperometry was used to measure current densities on the surface of a micro-copper electrode in pH 4 aqueous solutions containing 0.01 M glycine with or without 0.01 M BTA. In the presence of BTA the current density decreased as the inverse of the square root of time for a few seconds due to adsorption of BTA. At potentials above 0.4 ...

  17. Inactivation of Shiga toxin-producing Escherichia coli O104:H4 using cold atmospheric pressure plasma.

    Science.gov (United States)

    Baier, Matthias; Janssen, Traute; Wieler, Lothar H; Ehlbeck, Jörg; Knorr, Dietrich; Schlüter, Oliver

    2015-09-01

    From cultivation to the end of the post-harvest chain, heat-sensitive fresh produce is exposed to a variety of sources of pathogenic microorganisms. If contaminated, effective gentle means of sanitation are necessary to reduce bacterial pathogen load below their infective dose. The occurrence of rare or new serotypes raises the question of their tenacity to inactivation processes. In this study the antibacterial efficiency of cold plasma by an atmospheric pressure plasma-jet was examined against the Shiga toxin-producing outbreak strain Escherichia coli O104:H4. Argon was transformed into non-thermal plasma at a power input of 8 W and a gas flow of 5 L min(-1). Basic tests were performed on polysaccharide gel discs, including the more common E. coli O157:H7 and non-pathogenic E. coli DSM 1116. At 5 mm treatment distance and 10(5) cfu cm(-2) initial bacterial count, plasma reduced E. coli O104:H4 after 60 s by 4.6 ± 0.6 log, E. coli O157:H7 after 45 s by 4.5 ± 0.6 log, and E. coli DSM 1116 after 30 s by 4.4 ± 1.1 log. On the surface of corn salad leaves, gentle plasma application at 17 mm reduced 10(4) cfu cm(-2) of E. coli O104:H4 by 3.3 ± 1.1 log after 2 min, whereas E. coli O157:H7 was inactivated by 3.2 ± 1.1 log after 60 s. In conclusion, plasma treatment has the potential to reduce pathogens such as E. coli O104:H4 on the surface of fresh produce. However, a serotype-specific adaptation of the process parameters is required.

  18. Radiation-induced reduction of U(VI) ion at 6>pH>4 as observed by fast conductimetry

    Energy Technology Data Exchange (ETDEWEB)

    Broszkiewicz, R.K. (Institute of Nuclear Chemistry and Technology, Dorodna (Poland)); Vojnovic, B.; Michael, B.D. (Mount Vernon Hospital, Northwood (United Kingdom). Gray Lab.)

    1992-01-01

    Reactions between U(VI) and ionic species produced upon irradiation of aqueous (pH 4.4 or 5.5) and acetonic solutions have been observed directly using a.c. conductivity. Apart from e{sub aq}{sup -} also H{sub 3}O{sup +} reacts rapidly with hydroxides of the UO{sub 2}{sup 2+}. An electron pulse of 20 ns duration starts a sequence of phenomena which does not terminate until ca. 10 s. (author).

  19. Cancer cell-associated cytoplasmic B7–H4 is induced by hypoxia through hypoxia-inducible factor-1α and promotes cancer cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, You-Kyoung [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Park, Sae-Gwang; Choi, Il-Whan [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Lee, Soo-Woong [Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Lee, Sang Min [Department of Internal Medicine, Division of Hematology/Oncology, Busan Paik Hospital, Inje University, Busan 614-735 (Korea, Republic of); Choi, Inhak, E-mail: miccih@inje.ac.kr [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of)

    2015-04-03

    Aberrant B7–H4 expression in cancer tissues serves as a novel prognostic biomarker for poor survival in patients with cancer. However, the factor(s) that induce cancer cell-associated B7–H4 remain to be fully elucidated. We herein demonstrate that hypoxia upregulates B7–H4 transcription in primary CD138{sup +} multiple myeloma cells and cancer cell lines. In support of this finding, analysis of the Multiple Myeloma Genomics Portal (MMGP) data set revealed a positive correlation between the mRNA expression levels of B7–H4 and the endogenous hypoxia marker carbonic anhydrogenase 9. Hypoxia-induced B7–H4 expression was detected in the cytoplasm, but not in cancer cell membranes. Chromatin immunoprecipitation analysis demonstrated binding of hypoxia-inducible factor-1α (HIF-1α) to proximal hypoxia-response element (HRE) sites within the B7–H4 promoter. Knockdown of HIF-1α and pharmacological inhibition of HIF-1α diminished B7–H4 expression. Furthermore, knockdown of cytoplasmic B7–H4 in MCF-7 decreased the S-phase cell population under hypoxia. Finally, MMGP analysis revealed a positive correlation between the transcript levels of B7–H4 and proliferation-related genes including MKI67, CCNA1, and Myc in several patients with multiple myeloma. Our results provide insight into the mechanisms underlying B7–H4 upregulation and its role in cancer cell proliferation in a hypoxic tumor microenvironment. - Highlights: • Hypoxia upregulates B7–H4 transcription and protein expression. • Hypoxia-induced B7–H4 is detected in the cytoplasm, but not on membrane. • ChIP assay reveals a binding of HIF-1α to B7–H4 promoter at HRE site. • Knockdown and pharmacological inhibition of HIF-1α reduce B7–H4 expression. • B7–H4 knockdown decrease the number of cells in S-phase of cell cycle.

  20. Effects of histamine H1R-H4R-agonist on the airway epithelium of rabbits

    Institute of Scientific and Technical Information of China (English)

    Naushad A Dilkash; Trivendra Tripathi; Aijaz Ahmed Khan; Mohd Shahid; Haris M Khan; Mashiatullah Siddiqui; Rahat Ali Khan

    2010-01-01

    Objective: To explore the exact role of histamine receptors in respiratory system. Methods:The cohort comprised of six groups (group I control and group II-VI treated) containing five rabbits in each group. Control-group received vehicle (sterile distilled water) and treated groups received subcutaneous histamine (100μg/kg, b.i.d.), and H1R-agonist (HTMT), H2R-agonist (amthamine), H3R-agonist (R-(-)-α-methylhistamine) and H4R-agonist (clobenpropit) each in a dose of 10μg/kg, b.i.d. for 30 subsequent days. After completion of treatment, animals were euthanized and perfused with 10%buffered formalin. Small tissue blocks of trachea and lungs were processed for paraffin embedding. Observations were recorded in sample photomicrographs taken from 10μm thick. Haematoxylin and eosin stained sections. Results:It was observed that trachea and bronchi from histamine, H1R and H4R groups had only patches of hyperplastic and hypertrophied epithelium and in general, cells in the affected region were taller heaped up. The bronchiolar epithelia from all treated groups showed hypertrophy and hyperplasia throughout with most of the cells having rounded profile and appeared to bud out from the basal cells. Conclusions:It is concluded that histamine receptors on induction via its specific agonist can induce hypertrophy, hyperplasia of respiratory tract epithelia suggesting its role akin to growth stimulating factor and warranting further long-term study.

  1. Histone chaperone spt16 promotes redeposition of the original h3-h4 histones evicted by elongating RNA polymerase.

    Science.gov (United States)

    Jamai, Adil; Puglisi, Andrea; Strubin, Michel

    2009-08-14

    Nucleosomes are surprisingly dynamic structures in vivo, showing transcription-independent exchange of histones H2A-H2B genome-wide and exchange of H3-H4 mainly within the promoters of transcribed genes. In addition, nucleosomes are disrupted in front of and reassembled behind the elongating RNA polymerase. Here we show that inactivation of histone chaperone Spt16 in yeast results in rapid loss of H2B and H3 from transcribed genes but also from inactive genes. In all cases, histone loss is blocked by a transcription inhibitor, indicating a transcription-dependent event. Thus, nucleosomes are efficiently evicted by the polymerase but do not reform in the absence of Spt16. Yet exchange of nucleosomal H2B with free histones occurs normally, and, unexpectedly, incorporation of new H3 increases at all loci tested. This points to Spt16 restoring normal nucleosome structure by redepositing the displaced H3-H4 histones, thereby preventing incorporation of new histones and perhaps changes in histone modification patterns associated with ongoing transcription.

  2. Modulation of behavior by the histaminergic system: lessons from HDC-, H3R- and H4R-deficient mice.

    Science.gov (United States)

    Schneider, Erich H; Neumann, Detlef; Seifert, Roland

    2014-11-01

    Histamine, which is synthesized by histidine decarboxylase (HDC), does not only modulate the immune system, but is also acting as a neurotransmitter. Histaminergic neurons project from the tuberomamillary nucleus to numerous brain regions. Activation of presynaptic H3R inhibits the release of histamine and of non-histaminergic neurotransmitters. The phenotypes of Hdc(-/-)- and Hrh3(-/-) mice comprise behaviors related to locomotor activity, memory, cognition, anxiety, circadian rhythm, pain perception, food intake and addiction. We critically discuss these phenotypes that are probably caused by global changes of the histaminergic tone rather than by an altered stimulation of a single histamine receptor subtype. Constitutive H3R activity may add another layer of complexity by causing "histamine-independent histaminergic" processes, e.g. in Hdc(-/-) mice. We also discuss the clinical relevance of H3R- and HDC-deficient mice, e.g. the role of HDC in Tourette's syndrome. Finally, this review summarizes current knowledge on possible central H4R functions. Neuronal expression of H4R, however, is discussed controversially and a systematic behavioral characterization of Hrh4(-/-) mice is still missing.

  3. Superconductivity at approximately 100 K in dense SiH4(H2)2 predicted by first principles.

    Science.gov (United States)

    Li, Yinwei; Gao, Guoying; Xie, Yu; Ma, Yanming; Cui, Tian; Zou, Guangtian

    2010-09-07

    Motivated by the potential high-temperature superconductivity in hydrogen-rich materials, the high-pressure structures of SiH(4)(H(2))(2) in the pressure range 50-300 GPa were extensively explored by using a genetic algorithm. An intriguing layered orthorhombic (Ccca) structure was revealed to be energetically stable above 248 GPa with the inclusion of zero-point energy. The Ccca structure is metallic and composed of hydrogen shared SiH(8) dodecahedra layers intercalated by orientationally ordered molecular H(2). Application of the Allen-Dynes modified McMillan equation yields remarkably high superconducting temperatures of 98-107 K at 250 GPa, among the highest values reported so far for phonon-mediated superconductors. Analysis reveals a unique superconducting mechanism that the direct interactions between H(2) and SiH(4) molecules at high pressure play the major role in the high superconductivity, while the contribution from H(2) vibrons is minor.

  4. The effect of alginates on deoxycholic-acid-induced changes in oesophageal mucosal biology at pH 4.

    Science.gov (United States)

    Dettmar, Peter W; Strugala, Vicki; Tselepis, Chris; Jankowski, Janusz A

    2007-01-01

    Long-standing gastro-oesophageal reflux disease (GORD) can give rise to Barrett's oesophagus (BM), a metaplastic condition and precursor to oesophageal adenocarcinoma (AC). Oesophageal cancer was once rare but is now the 5th biggest cancer killer in the U.K. Reflux of bile acids into the oesophagus is implicated in the progression to BM as bile acids at pH 4 have been shown to induce c-myc expression, an oncogene upregulated in BM and AC. In the present study we investigated the role of the biopolymer alginate on bile acid induced molecular changes in oesophageal cell lines. OE21, OE33 and TE-7 oesophageal cell lines were exposed to 100 microM deoxycholic acid at pH 4 in the presence or absence of alginates. Levels of c-myc, E-cadherin, beta-catenin and Tcf signalling were determined by Real-Time PCR, Western blotting, immunofluoresence and reporter assays. All alginates tested were able to prevent the induction of c-myc by acidified deoxycholic acid in vitro. The upstream effects of acidified deoxycholic acid on E-cadherin, beta-catenin and Tcf signalling were also suppressed by alginate. Therefore, we have demonstrated that reflux of bile acids into the oesophagus initiates a potentially damaging molecular cascade of events using an in vitro model and that a biopolymer, alginate, can protect against these effects.

  5. PHF20 Readers Link Methylation of Histone H3K4 and p53 with H4K16 Acetylation

    Directory of Open Access Journals (Sweden)

    Brianna J. Klein

    2016-10-01

    Full Text Available PHF20 is a core component of the lysine acetyltransferase complex MOF (male absent on the first-NSL (non-specific lethal that generates the major epigenetic mark H4K16ac and is necessary for transcriptional regulation and DNA repair. The role of PHF20 in the complex remains elusive. Here, we report on functional coupling between methylation readers in PHF20. We show that the plant homeodomain (PHD finger of PHF20 recognizes dimethylated lysine 4 of histone H3 (H3K4me2 and represents an example of a native reader that selects for this modification. Biochemical and structural analyses help to explain this selectivity and the preference of Tudor2, another reader in PHF20, for dimethylated p53. Binding of the PHD finger to H3K4me2 is required for histone acetylation, accumulation of PHF20 at target genes, and transcriptional activation. Together, our findings establish a unique PHF20-mediated link between MOF histone acetyltransferase (HAT, p53, and H3K4me2, and suggest a model for rapid spreading of H4K16ac-enriched open chromatin.

  6. High-resolution spectroscopy of single Pr$^{3+}$ ions on the $^3$H$_4$-$^1$D$_2$ transition

    CERN Document Server

    Eichhammer, Emanuel; Götzinger, Stephan; Sandoghdar, Vahid

    2015-01-01

    Rare earth ions in crystals exhibit narrow spectral features and hyperfine-split ground states with exceptionally long coherence times. These features make them ideal platforms for quantum information processing in the solid state. Recently, we reported on the first high-resolution spectroscopy of single Pr$^{3+}$ ions in yttrium orthosilicate (YSO) nanocrystals. While in that work we examined the less explored $^3$H$_4$-$^3$P$_0$ transition at a wavelength of 488 nm, here we extend our investigations to the $^3$H$_4$-$^1$D$_2$ transition at 606 nm. In addition, we present measurements of the second-order autocorrelation function, fluorescence lifetime, and emission spectra of single ions as well as their polarization dependencies on both transitions; these data were not within the reach of the first experiments reported earlier. Furthermore, we show that by a proper choice of the crystallite, one can obtain narrower spectral lines and, thus, resolve the hyperfine levels of the excited state. We expect our re...

  7. In-situ investigation of the hydrogen release mechanism in bulk Mg2NiH4

    Science.gov (United States)

    Tran, Xuan Quy; McDonald, Stuart D.; Gu, Qinfen; Yamamoto, Tomokazu; Shigematsu, Koji; Aso, Kohei; Tanaka, Eishi; Matsumura, Syo; Nogita, Kazuhiro

    2017-02-01

    Hydrogen storage is an important aspect to enable the so-called hydrogen economy. Mg-Ni alloys are among the most promising candidates for solid-state hydrogen storage systems yet many questions remain unanswered regarding the hydriding/dehydriding mechanism of the alloys. Mg2NiH4 particularly has received much attention both for its potential as a hydrogen storage medium and also exhibits interesting properties relating to its different polymorphs. Here, the dehydriding mechanism in bulk Mg2NiH4 is investigated using in-situ ultra-high voltage transmission electron microscopy (TEM) combined with Synchrotron powder X-ray diffraction (XRPD) and differential scanning calorimetry (DSC). We find that the hydrogen release is based on a mechanism of nucleation and growth of Mg2NiHx (x∼0-0.3) solid solution grains and is greatly enhanced in the presence of crystal defects occurring as a result of the polymorphic phase transformation. Also importantly, with atomic resolution TEM imaging a high density of stacking faults is identified in the dehydrided Mg2NiHx (x∼0-0.3) lattices.

  8. Concerted Activities of Distinct H4K20 Methyltransferases at DNA Double-Strand Breaks Regulate 53BP1 Nucleation and NHEJ-Directed Repair

    Directory of Open Access Journals (Sweden)

    Creighton T. Tuzon

    2014-07-01

    Full Text Available Although selective binding of 53BP1 to dimethylated histone H4 lysine 20 (H4K20me2 at DNA double-strand breaks (DSBs is a necessary and pivotal determinant of nonhomologous end joining (NHEJ-directed repair, the enzymes that generate H4K20me2 at DSBs were unclear. Here, we determined that the PR-Set7 monomethyltransferase (H4K20me1 regulates de novo H4K20 methylation at DSBs. Rapid recruitment of PR-Set7 to DSBs was dependent on the NHEJ Ku70 protein and necessary for NHEJ-directed repair. PR-Set7 monomethyltransferase activity was required, but insufficient, for H4K20me2 and 53BP1 nucleation at DSBs. We determined that PR-Set7-mediated H4K20me1 facilitates Suv4-20 methyltransferase recruitment and catalysis to generate H4K20me2 necessary for 53BP1 binding. The orchestrated and concerted activities of PR-Set7 and Suv4-20 were required for proficient 53BP1 nucleation and DSB repair. This report identifies PR-Set7 as an essential component of NHEJ and implicates PR-Set7 as a central determinant of NHEJ-directed repair early in mammalian DSB repair pathway choice.

  9. On the Crystal Structure of [Cu(OH)2(H2O)2(4-C5H4NCOOH)2

    Institute of Scientific and Technical Information of China (English)

    Ng Seik Weng

    2003-01-01

    The compound described as [Cu(OH)2(H2O)2(4-C5H4NCOOH)2] in Chin. J. Struct. Chem., 2001, 20: 478-480 is instead the compound [Cu(H2O)4(4-C5H4NCOO)2], whose crystal structure has already been published elsewhere.

  10. Extraction of electron–ion differential scattering cross sections for C2H4 by laser-induced rescattering photoelectron spectroscopy

    DEFF Research Database (Denmark)

    Wang, C.; Okunishi, M.; Lucchese, R. R.;

    2012-01-01

    We have measured angle-resolved rescattering electron momentum distributions for C2H4 generated by intense infrared laser pulses and extracted large-angle elastic differential cross sections (DCSs) for electrons scattering from C2H4+. The angle-dependent ionization rate describing the initial...

  11. Optical, structural, and electrical properties of Mg2NiH4 thin films in situ grown by activated reactive evaporation

    NARCIS (Netherlands)

    Westerwaal, R. J.; Slaman, M.; Broedersz, C. P.; Borsa, D. M.; Dam, B.; Griessen, R.; Borgschulte, A.; Lohstroh, W.; Kooi, B.; ten Brink, Gert; Tschersich, K. G.; Fleischhauer, H. P.

    2006-01-01

    Mg2NiH4 thin films have been prepared by activated reactive evaporation in a molecular beam epitaxy system equipped with an atomic hydrogen source. The optical reflection spectra and the resistivity of the films are measured in situ during deposition. In situ grown Mg2NiH4 appears to be stable in

  12. Isolation and identification of a formaldehyde-degrading fungus Aspergillus spp.H4 strain%一株甲醛降解真菌Aspergillus spp.H4的分离鉴定

    Institute of Scientific and Technical Information of China (English)

    黄赛花; 陈能场; 胡文锋; 周建民; 毕洪亮

    2007-01-01

    甲醛是一种广泛使用和很重要的化工原材料,但它同时也是对大多数生物有机体有高毒性的物质.通过添加甲醛的选择性培养基从淤泥里分离了一株甲醛耐受真菌,将其接种于加孟加拉红的PDA培养基、察氏培养基、麦芽汁培养基平板培养,观察它的培养特征和孢子结构,结合DNA提取、PCR扩增、产物测序、GenBank比对等分子鉴定手段,结果表明:其培养特征、显微特征和黄曲霉(Aspergillus flavus)相似,18S rDNA序列与黄曲霉(Aspergillus flavus)同源率达99.8%.我们把它命名为Aspergillus flavus H4.该真菌最适生长pH值为pH 5.5,在培养的144 h内ρ(甲醛)从1241 mg·L-1下降到4 mg·L-1.在培养的96 h内ρ(甲醛)下降迅速,A值上升缓慢,当ρ(甲醛)下降到10 mg·L-1时,也就是120 h时, A值迅速上升,ρ(甲醛)下降缓慢.结论是这株Aspergillus flavus H4是甲醛耐受(降解)真菌.

  13. Histone deacetylase 1, 2, 6 and acetylated histone H4 in B- and T-cell lymphomas

    DEFF Research Database (Denmark)

    Marquard, L.; Poulsen, C.B.; Gjerdrum, L.M.;

    2009-01-01

    AIMS: Histone deacetylase (HDAC) inhibitors are novel therapeutics in the treatment of peripheral T-cell lymphoma, unspecified (PTCL) and diffuse large B-cell lymphoma (DLBCL), where, for unknown reasons, T-cell malignancies appear to be more sensitive than B-cell malignancies. The aim was to det......AIMS: Histone deacetylase (HDAC) inhibitors are novel therapeutics in the treatment of peripheral T-cell lymphoma, unspecified (PTCL) and diffuse large B-cell lymphoma (DLBCL), where, for unknown reasons, T-cell malignancies appear to be more sensitive than B-cell malignancies. The aim...... was to determine HDAC expression in DLBCL and PTCL which has not previously been investigated. METHODS AND RESULTS: The expression of HDAC1, HDAC2, HDAC6 and acetylated histone H4 was examined immunohistochemically in 31 DLBCL and 45 PTCL. All four markers showed high expression in both DLBCL and PTCL compared...

  14. Analysis of Performance of a Radiation-Hard, Highly-Segmented Shashlik Electromagnetic Calorimeter in the CERN H4 Testbeam

    Science.gov (United States)

    Culbertson, Eric; Neu, Chris; Dezoort, Gage; Ledovskoy, Alexander; Sinthuprasith, Tutanon

    2017-01-01

    A shashlik style calorimeter with alternating tungsten and LYSO crystal plates underwent testbeam analysis to determine its energy resolution. A single shashlik module is a tiny rectangular prism composed of 28 2.5 mm thick tungsten plates alternating with 29 1.5 mm thick LYSO crystals, which each have a length and width of 14 mm. The expected stochastic energy resolution of this design was predicted to be 10%/√{ E } by standalone GEANT4 simulations and subsequent beam tests. A 4x4 array of shashlik modules has been tested using the H4 beamline at CERN. Following a correction to the nonlinearity of SiPM response, the energy resolution was determined.

  15. Excess Thermal Energy In The Cell Loaded With Mixture of Ni Powder And Li[AlH4

    Science.gov (United States)

    Nguyen-Kuok, Shi; Malakhov, Yury; Korotkikh, Ivan

    2016-09-01

    Interest has significantly increased in the study of Low-Energy Nuclear Reactions. Especially after the publication of the test results from Andrea Rossi's high-temperature heat source that operates on a mixture of Nickel powder and Lithium Aluminum Hydride. Initial experiments showed that the reaction is unstable; occurring in a narrow temperature range (in practice, it is outside the melting temperature of the fuel materials). In this work we describe the design of the heat generator, the calorimetric method for measuring the amount of heat energy. The results demonstrate excess heat during heating the powder mixture of Ni and Li[AlH4] to temperatures ranging from 1030-1140 °C. The generator did not expose an X-ray photographic emulsion. Professor.

  16. Intense laser induced field ionization of C2H2, C2H4,and C2H6

    Institute of Scientific and Technical Information of China (English)

    GAO Lirong; JI Na; XONG Yijia; TANG Xiaoping; KONG Fan'ao

    2003-01-01

    Using HOMO Field Ionization Model, the tunneling probabilities and the theoretical threshold intensities of the field ionizations of acetylene, ethylene, and ethane in intense laser field are calculated. C2H2, C2H4, and C2H6 were irradiated by 800 nm, 100 fs laser pulses with the intensity range of 1013-1014 W/cm2. A TOF-mass spectrometer was coupled to the laser system and used to experimentally investigate the field ionization of these molecules. The experimental ionization threshold intensities are obtained. The calculating results of the three molecules agree well with the experimental results, indicating that HOMO Field Ionization Model is valid for the ionization of polyatomic molecules in intense laser field.

  17. Density Functional Studies on Isonicotinato Lead(II) Complex [Pb(C5H4NCOO)2

    Institute of Scientific and Technical Information of China (English)

    ZHAO Pu-Su; JIAN Fang-Fang; LI Chun-Lei; ZHENG Jian

    2006-01-01

    The title compound of isonicotinato lead(II) [Pb(C5H4NCOO)2] has been optimized at B3LYP/LANL2DZ level of theory and calculated results show that the lead(II) ion adopts 4-coordinate geometry. Atomic charge distributions indicate that during forming the title compound, each isonicotinic acid ion transfers -0.452 e to lead(II) ion. The electronic spectra calculations show that there exist two absorption bands and the electronic transitions are mainly derived from the contribution of intraligand π→π* transition and ligand-to-metal charge transfer (LMCT) transition. The thermodynamic properties of the title compound at different temperatures have been calculated and corresponding relations between property and temperature have also been obtained. The calcu- lation of the second order optical nonlinearity was carried out, and the molecular hyperpo- larizability was 3.62365*10-30 esu.

  18. Silane photoabsorption spectra near the Si 2p thresholds: the geometry of Si 2p excited SiH4

    Institute of Scientific and Technical Information of China (English)

    张卫华; 许如清; 李家明

    2003-01-01

    Based on the multiple-scattering self-consistent-field method, we have studied the photoabsorption spectra near the Si 2p thresholds of silane. According to our calculations, the clear assignments of the inner-shell photoabsorption spectra are provided. In comparison with the high-resolution experimental spectra, the geometric structure of the Si 2p-excited SiH4** is recommended to be of a C2v symmetry. More specifically, the Si 2p-excited Si4** have two bond lengths of 2.50 a.u. and another two bond lengths of 2.77 a.u., and the corresponding two bond angles are 104.0° and 112.5° respectively.

  19. One-Dimensional Fluid Model of Pulse Modulated Radio-Frequency SiH4/N2/O2 Discharge

    Institute of Scientific and Technical Information of China (English)

    王燕; 刘相梅; 宋远红; 王友年

    2012-01-01

    Driven by pulse modulated radio-frequency plasma in capacitively coupled discharge are studied by source, the behavior of SiH4/N2/02 using a one-dimensional fluid model. Totally, 48 different species (electrons, ions, neutrals, radicals and excited species) are involved in this simulation. Time evolution of the particle densities and electron temperature with different duty cycles are obtained, as well as the electronegativity nsiH-3 /ne of the main negative ion (Sill3 ). The results show that, by reducing the duty cycle, higher electron temperature and particle density can be achieved for the same average dissipated power, and the ion energy can also be effectively reduced, which will offer evident improvement in plasma deposition processes compared with the case of continuous wave discharge.

  20. Latitudinal variability in Jupiter's tropospheric disequilibrium species: GeH$_4$, AsH$_3$ and PH$_3$

    CERN Document Server

    Giles, Rohini S; Irwin, Patrick G J

    2016-01-01

    Jupiter's tropospheric composition is studied using high resolution spatially-resolved 5-micron observation from the CRIRES instrument at the Very Large Telescope. The high resolving power (R=96,000) allows us to spectrally resolve the line shapes of individual molecular species in Jupiter's troposphere and, by aligning the slit north-south along Jupiter's central meridian, we are able to search for any latitudinal variability. Despite the high spectral resolution, we find that there are significant degeneracies between the cloud structure and aerosol scattering properties that complicate the retrievals of tropospheric gaseous abundances and limit conclusions on any belt-zone variability. However, we do find evidence for variability between the equatorial regions of the planet and the polar regions. Arsine (AsH$_3$) and phosphine (PH$_3$) both show an enhancement at high latitudes, while the abundance of germane (GeH$_4$) remains approximately constant. These observations contrast with the theoretical predict...

  1. Synthesis and Crystal Structure of a New Double 2D Layer Complex Assembled by H4btec

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Assembly of H4btec with cobalt(Ⅱ) acetate afforded a new double 2D layer coor- dination polymer, [Co(btec)1/2(H2O)4·2H2O]n (H4btec = benzene-1,2,4,5-tetracarboxylic acid) 1. The polymeric structure has been characterized by single-crystal X-ray diffraction, FT-IR and thermal analysis. The crystal is of triclinic, space group P with a = 10.8762(2), b = 11.1411(1), c = 11.5084(3)(A), α = 82.8950(10), β = 63.0050(10), γ = 62.1500(10)°, V = 1091.72(4)(A)3, C5H13CoO10, Mr = 292.08, Z = 4, Dc = 1.777 g/cm3, μ = 1.612 mm-1, F(000) = 600, R = 0.0578, and wR = 0.2162 for 3576 observed reflections (I > 2σ(I)). Complex 1 consists of a new double 2D layer structure [Co(btec)1/2(H2O)4]n, both consisting of 4 + 4 grids with the sizes of 11.3667(2)(A) × 11.5084(3)(A)(Co(1)-Co(1A) × Co(2A)-Co(2B)) and 11.5084(3)(A)× 11.3667(2)(A) (Co(3)-Co(3C) × Co(4)- Co(4A)), respectively. The phenyl rings are at the corners while the Co(Ⅱ) atoms are in the sides of the grids, and lattice water molecules decorate between the layers. Hydrogen bonds between the layers and lattice water molecules result in the final 3D framework.

  2. High-level ab initio predictions for the ionization energies and heats of formation of five-membered-ring molecules: thiophene, furan, pyrrole, 1,3-cyclopentadiene, and borole, C4H4X/C4H4X+ (X = S, O, NH, CH2, and BH).

    Science.gov (United States)

    Lo, Po-Kam; Lau, Kai-Chung

    2011-02-10

    The ionization energies (IEs) and heats of formation (ΔH°(f0)/ΔH°(f298)) for thiophene (C(4)H(4)S), furan (C(4)H(4)O), pyrrole (C(4)H(4)NH), 1,3-cyclopentadiene (C(4)H(4)CH(2)), and borole (C(4)H(4)BH) have been calculated by the wave function-based ab initio CCSD(T)/CBS approach, which involves the approximation to the complete basis set (CBS) limit at the coupled-cluster level with single and double excitations plus a quasi-perturbative triple excitation [CCSD(T)]. Where appropriate, the zero-point vibrational energy correction (ZPVE), the core-valence electronic correction (CV), and the scalar relativistic effect (SR) are included in these calculations. The respective CCSD(T)/CBS predictions for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2), being 8.888, 8.897, 8.222, and 8.582 eV, are in excellent agreement with the experimental values obtained from previous photoelectron and photoion measurements. The ΔH°(f0)/ΔH°(f298) values for the aforementioned molecules and their corresponding cations have also been predicted by the CCSD(T)/CBS method, and the results are compared with the available experimental data. The comparisons between the CCSD(T)/CBS predictions and the experimental values for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2) suggest that the CCSD(T)/CBS procedure is capable of predicting reliable IE values for five-membered-ring molecules with an uncertainty of ±13 meV. In view of the excellent agreements between the CCSD(T)/CBS predictions and the experimental values for C(4)H(4)S, C(4)H(4)O, C(4)H(4)NH, and C(4)H(4)CH(2), the similar CCSD(T)/CBS IE and ΔH°(f0)/ΔH°(f298) predictions for C(4)H(4)BH, whose thermochemical data are not readily available due to its reactive nature, should constitute a reliable data set. The CCSD(T)/CBS IE(C(4)H(4)BH) value is 8.868 eV, and ΔH°(f0)/ΔH°(f298) values for C(4)H(4)BH and C(4)H(4)BH(+) are 269.5/258.6 and 1125.1/1114.6 kJ/mol, respectively. The highest occupied molecular orbitals

  3. The histone H4 lysine 20 monomethyl mark, set by PR-Set7 and stabilized by L(3mbt, is necessary for proper interphase chromatin organization.

    Directory of Open Access Journals (Sweden)

    Ayako Sakaguchi

    Full Text Available Drosophila PR-Set7 or SET8 is a histone methyltransferase that specifically monomethylates histone H4 lysine 20 (H4K20. L(3MBT has been identified as a reader of methylated H4K20. It contains several conserved domains including three MBT repeats binding mono- and dimethylated H4K20 peptides. We find that the depletion of PR-Set7 blocks de novo H4K20me1 resulting in the immediate activation of the DNA damage checkpoint, an increase in the size of interphase nuclei, and drastic reduction of cell viability. L(3mbt on the other hand stabilizes the monomethyl mark, as L(3mbt-depleted S2 cells show a reduction of more than 60% of bulk monomethylated H4K20 (H4K20me1 while viability is barely affected. Ploidy and basic chromatin structure show only small changes in PR-Set7-depleted cells, but higher order interphase chromatin organization is significantly affected presumably resulting in the activation of the DNA damage checkpoint. In the absence of any other known functions of PR-Set7, the setting of the de novo monomethyl mark appears essential for cell viability in the presence or absence of the DNA damage checkpoint, but once newly assembled chromatin is established the monomethyl mark, protected by L(3mbt, is dispensable.

  4. [Molecular investigation of enteroaggregative, shiga toxin-producing E. coli O104:H4 isolated in Poland during the recent international outbreak--characteristic of epidemic clone].

    Science.gov (United States)

    Januszkiewicz, Aleksandra; Chróst, Anna; Wołkowicz, Tomasz; Madajczak, Grzegorz; Wasiak, Monika; Szych, Jolanta

    2011-01-01

    Since early May 2011 a large food-borne outbreak caused by E. coli O104:H4 affected Germany then spread over 13 European countries, U.S.A. and Canada. The outbreak strain was found to possess an unusual combination of enteroaggregative E. coli pathotype with StxII. In this report we described the molecular investigation of epidemic clone in Poland during the international outbreak. We confirmed three cases of E. coli O104:H4 infections. The molecular characteristics of the Polish E. coli O104:H4 isolates including virulence profile, antimicrobial resistance, PFGE and plasmids profiles were corresponded with Germany outbreak strains.

  5. Prognostic investigations of B7-H1 and B7-H4 expression levels as independent predictor markers of renal cell carcinoma.

    Science.gov (United States)

    Safaei, Hamid Reza; Rostamzadeh, Ayoob; Rahmani, Omid; Mohammadi, Mohsen; Ghaderi, Omar; Yahaghi, Hamid; Ahmadi, Koroosh

    2016-06-01

    In order to evaluate the correlation of B7-H4 and B7-H1 with renal cell carcinoma (RCC), we analyzed B7-H1 and B7-H4 expressions and their clinical significance by immunohistochemical method. Our result indicated that B7-H4-positive staining was detected in 58.13 % of RCC tissues (25 tissues tumors), and there were 18 tissues of patients without detectable B7-H4. Furthermore, 21 cases (48.83 %) were B7-H1-positive. Positive tumor expressions of B7-H4 and B7-H1 were markedly related to advanced TNM stage (P = 0.001; P = 0.014), high grade (P = 0.001; P = 002), and larger tumor size (P = 0.002; P = 024) in RCC tissues than patients with B7-H4-negative and B7-H1-negative in RCC tissues. The patients with B7-H1 and B7-H4-positive expressions were found to be markedly correlated with the overall survival of the patients (P < 0.05) and tended to have an increased risk of death when compared with negative expression groups. Univariate analysis showed that B7-H4 and B7-H1 expressions, TNM stage, high grade, and tumor size were significantly related to the prognosis of RCC. Furthermore, multivariate analysis showed that B7-H4 and B7-H1 expressions decreased overall survival. The adjusted HR for B7-H1 was 2.83 (95 % CI 1.210-2.971; P = 0.031) and also was 2.918 (95 % CI 1.243-3.102; P = 0.006) for B7-H4 that showed these markers were independent prognostic factors in RCC patients. The expressions of B7-H1 and B7-H4 in RCC patients indicate that these markers may be as a predictor of tumor development and death risk. Further investigations can be helpful to confirm B7-H1 and B7-H4 roles as an independent predictor of clinical RCC outcome.

  6. No evidence of the Shiga toxin-producing E. coli O104:H4 outbreak strain or enteroaggregative E. coli (EAEC found in cattle faeces in northern Germany, the hotspot of the 2011 HUS outbreak area

    Directory of Open Access Journals (Sweden)

    Wieler Lothar H

    2011-11-01

    Full Text Available Abstract Background Ruminants, in particular bovines, are the primary reservoir of Shiga toxin-producing E. coli (STEC, but whole genome analyses of the current German ESBL-producing O104:H4 outbreak strain of sequence type (ST 678 showed this strain to be highly similar to enteroaggregative E. coli (EAEC. Strains of the EAEC pathotype are basically adapted to the human host. To clarify whether in contrast to this paradigm, the O104:H4 outbreak strain and/or EAEC may also be able to colonize ruminants, we screened a total of 2.000 colonies from faecal samples of 100 cattle from 34 different farms - all located in the HUS outbreak region of Northern Germany - for genes associated with the O104:H4 HUS outbreak strain (stx2, terD, rfbO104, fliCH4, STEC (stx1, stx2, escV, EAEC (pAA, aggR, astA, and ESBL-production (blaCTX-M, blaTEM, blaSHV. Results The faecal samples contained neither the HUS outbreak strain nor any EAEC. As the current outbreak strain belongs to ST678 and displays an en-teroaggregative and ESBL-producing phenotype, we additionally screened selected strains for ST678 as well as the aggregative adhesion pattern in HEp-2 cells. However, we were unable to find any strains belonging to ST678 or showing an aggregative adhesion pattern. A high percentage of animals (28% shed STEC, corroborating previous knowl-edge and thereby proving the validity of our study. One of the STEC also harboured the LEE pathogenicity island. In addition, eleven animals shed ESBL-producing E. coli. Conclusions While we are aware of the limitations of our survey, our data support the theory, that, in contrast to other Shiga-toxin producing E. coli, cattle are not the reservoir for the O104:H4 outbreak strain or other EAEC, but that the outbreak strain seems to be adapted to humans or might have yet another reservoir, raising new questions about the epidemiology of STEC O104:H4.

  7. Detection of virulence-associated genes characteristic of intestinal Escherichia coli pathotypes, including the enterohemorrhagic/enteroaggregative O104:H4, in bovines from Germany and Spain.

    Science.gov (United States)

    Cabal, Adriana; Geue, Lutz; Gómez-Barrero, Susana; Barth, Stefanie; Bárcena, Carmen; Hamm, Katharina; Porrero, M Concepción; Valverde, Aránzazu; Cantón, Rafael; Menge, Christian; Gortázar, Christian; Domínguez, Lucas; Álvarez, Julio

    2015-08-01

    Cattle are reservoirs of enterohemorrhagic Escherichia coli; however, their role in the epidemiology of other pathogenic E. coli remains undefined. A new set of quantitative real-time PCR assays for the direct detection and quantification of nine virulence-associated genes (VAGs) characteristic of the most important human E. coli pathotypes and four serotype-related genes (wzxO104 , fliCH4 , rbfO157 , fliCH7 ) that can be used as a surveillance tool for detection of pathogenic strains was developed. A total of 970 cattle fecal samples were collected in slaughterhouses in Germany and Spain, pooled into 134 samples and analyzed with this tool. stx1, eae and invA were more prevalent in Spanish samples whereas bfpA, stx2, ehxA, elt, est and the rbfO157 /fliCH7 combination were observed in similar proportions in both countries. Genes characteristic of the hybrid O104:H4 strain of the 2011 German outbreak (stx2/aggR/wzxO104 /fliCH4 ) were simultaneously detected in six fecal pools from one German abattoir located near the outbreak epicenter. Although no isolate harboring the full stx2/aggR/wzxO104 /fliCH4 combination was cultured, sequencing of the aggR positive PCR products revealed 100% homology to the aggR from the outbreak strain. Concomitant detection by this direct approach of VAGs from a novel human pathogenic E. coli strain in cattle samples implies that the E. coli gene pool in these animals can be implicated in de novo formation of such highly-virulent strains. The application of this set of qPCRs in surveillance studies could be an efficient early-warning tool for the emergence of zoonotic E. coli in livestock.

  8. Evaluation of the validity of the UN SADT H.4 test for solid organic peroxides and self-reactive substances.

    Science.gov (United States)

    Steensma, M; Schuurman, P; Malow, M; Krause, U; Wehrstedt, K-D

    2005-01-31

    Many self-accelerating decomposition temperatures (SADTs) of solid organic peroxides and self-reactive substances have been determined with the UN test method H.4, which is a scaled down test in a small Dewar vessel. For solid organic peroxides and solid self-reactive substances Fierz has questioned this procedure in a recent paper. Fierz concluded that the Dewar test results should not be extrapolated to beyond 8l packages, owing to the thermal insulation value of solids. On the other hand, long term experience with the test, with a great variety of solid organic peroxides and self-reactive substances show about equal critical temperatures in the small Dewar vessel and on 50 kg scale. In the present work, we first checked, by numerical simulations, the Dewar scale versus the larger scale, in a way comparable with Fierz' method: both scales are simulated by spheres, consisting of a number of annular layers, for the large scale the usual external heat loss term is used but for the small scale the outside heat transfer is strongly limited. The outcome of these simulations, covering a variety of physical parameters, supports the concerns expressed by Fierz. After this, we performed accurate cooling and heating experiments with solid organic peroxide in the usual Dewar vessel, provided with a large set of thermocouples. The results of these experiments showed that the simulation model for the Dewar vessel has to be changed from a spherical analogue to a short cylinder of solid material with heat exchange mainly via its top (U(top) approximately 3.5 W/(m(2)K), overall heat transfer coefficient) and some heat exchange (U(side) approximately 0.29 W/(m(2)K)) through its cylindrical and bottom part. With this "modified cylinder" model (being neither an infinitely long cylinder nor a slab) of the Dewar vessel, we found that the UN method H.4 enables an accurate prediction of the SADT, with small deviations of 0+/-2.5 degrees C. Further, by performing a truly three

  9. Conformational Analysis of Seven Membered Nitrogen Heterocycles Employing Molecular Modeling. Part II: 1-(ONitrophenyl-2-Phenyl-1h-4,5,6,7-Tetrahydro-1,3-Diazepine

    Directory of Open Access Journals (Sweden)

    Mónica E. Hedrera

    2000-03-01

    Full Text Available Geometry optimization of 1-(o-nitrophenyl-2-phenyl-1H-4,5,6,7-tetrahydro-1,3-diazepine is performed by means of molecular modeling. Results are correlated with theoretical and experimental UV spectra.

  10. A geometric proof of the upper bound on the size of partial spreads in H(4n+1, q²)

    OpenAIRE

    Vanhove, Frédéric

    2011-01-01

    We give a geometric proof of the upper bound of q(2n+1) + 1 on the size of partial spreads in the polar space H(4n + 1, q(2)). This bound is tight and has already been proved in an algebraic way. Our alternative proof also yields a characterization of the partial spreads of maximum size in H(4n + 1, q(2)).

  11. Synthesis of a stable adduct of dialane(4) (Al2H4) via hydrogenation of a magnesium(I) dimer

    Science.gov (United States)

    Bonyhady, Simon J.; Collis, David; Frenking, Gernot; Holzmann, Nicole; Jones, Cameron; Stasch, Andreas

    2010-10-01

    The desorption of dihydrogen from magnesium(II) hydride, MgH2 (containing 7.6 wt% H), is reversible. MgH2 therefore holds promise as a hydrogen storage material in devices powered by fuel cells. We believed that dimeric magnesium(I) dimers (LMgMgL, L = β-diketiminate) could find use as soluble models to aid the study of the mechanisms and/or kinetics of the hydrogenation of magnesium and its alloys. Here, we show that LMgMgL can be readily hydrogenated to yield LMg(µ-H)2MgL by treatment with aluminium(III) hydride complexes. In one case, hydrogenation was reversed by treating LMg(µ-H)2MgL with potassium metal. The hydrogenation by-products are the first thermally stable, neutral aluminium(II) hydride complexes to be produced, one of which, [{(IPr)(H)2Al}2] (IPr = :C[{(C6H3-i-Pr2-2,6)NCH}2]), is an N-heterocyclic carbene adduct of the elusive parent dialane(4) (Al2H4). A computational analysis of this compound is presented.

  12. Kinetochore function and chromosome segregation rely on critical residues in histones H3 and H4 in budding yeast.

    Science.gov (United States)

    Ng, Tessie M; Lenstra, Tineke L; Duggan, Nicole; Jiang, Shuangying; Ceto, Steven; Holstege, Frank C P; Dai, Junbiao; Boeke, Jef D; Biggins, Sue

    2013-11-01

    Accurate chromosome segregation requires that sister kinetochores biorient and attach to microtubules from opposite poles. Kinetochore biorientation relies on the underlying centromeric chromatin, which provides a platform to assemble the kinetochore and to recruit the regulatory factors that ensure the high fidelity of this process. To identify the centromeric chromatin determinants that contribute to chromosome segregation, we performed two complementary unbiased genetic screens using a library of budding yeast mutants in every residue of histone H3 and H4. In one screen, we identified mutants that lead to increased loss of a nonessential chromosome. In the second screen, we isolated mutants whose viability depends on a key regulator of biorientation, the Aurora B protein kinase. Nine mutants were common to both screens and exhibited kinetochore biorientation defects. Four of the mutants map near the unstructured nucleosome entry site, and their genetic interaction with reduced IPL1 can be suppressed by increasing the dosage of SGO1, a key regulator of biorientation. In addition, the composition of purified kinetochores was altered in six of the mutants. Together, this work identifies previously unknown histone residues involved in chromosome segregation and lays the foundation for future studies on the role of the underlying chromatin structure in chromosome segregation.

  13. Saccharomyces cerevisiae MHF complex structurally resembles the histones (H3-H4)₂ heterotetramer and functions as a heterotetramer.

    Science.gov (United States)

    Yang, Hui; Zhang, Tianlong; Tao, Ye; Wu, Lijing; Li, Hong-Tao; Zhou, Jin-Qiu; Zhong, Chen; Ding, Jianping

    2012-02-08

    Fanconi anemia (FA) is a chromosomal instability disorder associated with deficiencies in the Fanconi anemia complementation group (FANC) network. A complex consisting of FANCM-associated histone-fold proteins 1 and 2 (MHF1 and MHF2) has been shown to act cooperatively with FANCM in DNA damage repair in the FA pathway. Here we report the structure of Saccharomyces cerevisiae MHF complex in which MHF1 and MHF2 assume a typical histone fold, and the complex has a heterotetrameric architecture similar to that of the histones (H3-H4)₂ heterotetramer. Loop L2 of MHF1 is probably involved in DNA binding, and loop L3 and helices α2 and α3 of one MHF1 subunit interact with those of the other to form two heterotetramer interfaces. Further genetic data demonstrate that the heterotetramer assembly is essential for the function of the complex in DNA repair. These results provide, to the best of our knowledge, new mechanistic insights into the function of the MHF complex. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Levuglandin forms adducts with histone h4 in a cyclooxygenase-2-dependent manner, altering its interaction with DNA.

    Science.gov (United States)

    Carrier, Erica J; Zagol-Ikapitte, Irene; Amarnath, Venkataraman; Boutaud, Olivier; Oates, John A

    2014-04-22

    Inflammation and subsequent cyclooxygenase-2 (COX-2) activity has long been linked with the development of cancer, although little is known about any epigenetic effects of COX-2. A product of COX-2 activation, levuglandin (LG) quickly forms covalent bonds with nearby primary amines, such as those in lysine, which leads to LG-protein adducts. Here, we demonstrate that COX-2 activity causes LG-histone adducts in cultured cells and liver tissue, detectable through LC-MS, with the highest incidence in histone H4. Adduction is blocked by a γ-ketoaldehyde scavenger, which has no effect on COX-2 activity as measured by PGE2 production. Formation of the LG-histone adduct is associated with an increased histone solubility in NaCl, indicating destabilization of the nucleosome structure; this is also reversed with scavenger treatment. These data demonstrate that COX-2 activity can cause histone adduction and loosening of the nucleosome complex, which could lead to altered transcription and contribute to carcinogenesis.

  15. Determination of molecular line parameters for acrolein (C(3)H(4)O) using infrared tunable diode laser absorption spectroscopy.

    Science.gov (United States)

    Harward, Charles N; Thweatt, W David; Baren, Randall E; Parrish, Milton E

    2006-04-01

    Acrolein (C(3)H(4)O) molecular line parameters, including infrared (IR) absorption positions, strengths, and nitrogen broadened half-widths, must be determined since they are not included in the high resolution transmission (HITRAN) molecular absorption database of spectral lines. These parameters are required for developing a quantitative analytical method for measuring acrolein in a single puff of cigarette smoke using tunable diode laser absorption spectroscopy (TDLAS). The task is complex since acrolein has many highly overlapping infrared absorption lines in the room temperature spectrum and the cigarette smoke matrix contains thousands of compounds. This work describes the procedure for estimating the molecular line parameters for these overlapping absorption lines in the wavenumber range (958.7-958.9 cm(-1)) using quantitative reference spectra taken with the infrared lead-salt TDLAS instrument at different pressures and concentrations. The nitrogen broadened half-width for acrolein is 0.0937 cm(-1)atm(-1) and to our knowledge, is the first time it has been reported in the literature.

  16. Approaches to treatment of emerging Shiga toxin-producing Escherichia coli infections highlighting the O104:H4 serotype.

    Science.gov (United States)

    Rahal, Elias A; Fadlallah, Sukayna M; Nassar, Farah J; Kazzi, Natalie; Matar, Ghassan M

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) are a group of diarrheagenic bacteria associated with foodborne outbreaks. Infection with these agents may result in grave sequelae that include fatality. A large number of STEC serotypes has been identified to date. E. coli serotype O104:H4 is an emerging pathogen responsible for a 2011 outbreak in Europe that resulted in over 4000 infections and 50 deaths. STEC pathogenicity is highly reliant on the production of one or more Shiga toxins that can inhibit protein synthesis in host cells resulting in a cytotoxicity that may affect various organ systems. Antimicrobials are usually avoided in the treatment of STEC infections since they are believed to induce bacterial cell lysis and the release of stored toxins. Some antimicrobials have also been reported to enhance toxin synthesis and production from these organisms. Various groups have attempted alternative treatment approaches including the administration of toxin-directed antibodies, toxin-adsorbing polymers, probiotic agents and natural remedies. The utility of antibiotics in treating STEC infections has also been reconsidered in recent years with certain modalities showing promise.

  17. Insights into chondrule formation process and shock-thermal history of the Dergaon chondrite (H4-5

    Directory of Open Access Journals (Sweden)

    D. Ray

    2017-05-01

    Full Text Available The Dergaon fall represents a shock-melted H4-5 (S5 ordinary chondrite which includes at least ten textural varieties of chondrules and belongs to the high chondrule-matrix ratio type. Our study reveals that the chondrules are of diverse mineralogy with variable olivine-pyroxene ratios (Type II, igneous melt textures developed under variable cooling rates and formed through melt fractionations from two different melt reservoirs. Based on the experimental analogues, mineralogical associations and phase compositions, it is suggested that the Dergaon chondrules reflect two contrasting environments: a hot, dust-enriched and highly oxidized nebular environment through melting, without significant evaporation, and an arrested reducing environment concomitant with major evaporation loss of alkali and highly volatile trace elements. Coexistence of chlorapatite and merrillite suggests formation of the Dergaon matrix in an acidic accretionary environment. Textural integration and chemical homogenization occurred at ∼1 atmospheric pressure and a mean temperature of 765 °C mark the radiogenic thermal event. Equilibrated shock features (olivine mosaicism, diaplectic plagioclase, polycrystalline troilite due to an impact-induced thermal event reflect a shock pressure >45 GPa and temperature of 600 °C. By contrast, the local disequilibrium shock features (silicate melt veins comprising of olivine crystallites, troilite melt veins and metal droplets correspond to a shock pressure up to 75 GPa and temperature >950 °C.

  18. Latitudinal variability in Jupiter's tropospheric disequilibrium species: GeH4, AsH3 and PH3

    Science.gov (United States)

    Giles, R. S.; Fletcher, L. N.; Irwin, P. G. J.

    2017-06-01

    Jupiter's tropospheric composition is studied using high-resolution, spatially-resolved 5-μm observations from the CRIRES instrument at the Very Large Telescope. The high resolving power (R = 96,000) allows us to spectrally resolve the line shapes of individual molecular species in Jupiter's troposphere and, by aligning the slit north-south along Jupiter's central meridian, we are able to search for any latitudinal variability. Despite the high spectral resolution, we find that there are significant degeneracies between the cloud structure and aerosol scattering properties that complicate the retrievals of tropospheric gaseous abundances and limit conclusions on any belt-zone variability. However, we do find evidence for variability between the equatorial regions of the planet and the polar regions. Arsine (AsH3) and phosphine (PH3) both show an enhancement at high latitudes, while the abundance of germane (GeH4) remains approximately constant. These observations contrast with the theoretical predictions from Wang et al. (2016) and we discuss the possible explanations for this difference.

  19. Synthesis of a stable adduct of dialane(4) (Al2H4) via hydrogenation of a magnesium(I) dimer.

    Science.gov (United States)

    Bonyhady, Simon J; Collis, David; Frenking, Gernot; Holzmann, Nicole; Jones, Cameron; Stasch, Andreas

    2010-10-01

    The desorption of dihydrogen from magnesium(II) hydride, MgH2 (containing 7.6 wt% H), is reversible. MgH2 therefore holds promise as a hydrogen storage material in devices powered by fuel cells. We believed that dimeric magnesium(I) dimers (LMgMgL, L=β-diketiminate) could find use as soluble models to aid the study of the mechanisms and/or kinetics of the hydrogenation of magnesium and its alloys. Here, we show that LMgMgL can be readily hydrogenated to yield LMg(µ-H)2MgL by treatment with aluminium(III) hydride complexes. In one case, hydrogenation was reversed by treating LMg(µ-H)2MgL with potassium metal. The hydrogenation by-products are the first thermally stable, neutral aluminium(II) hydride complexes to be produced, one of which, [{(IPr)(H)2Al}2] (IPr=:C[{(C6H3-i-Pr(2)-2,6)NCH}2]), is an N-heterocyclic carbene adduct of the elusive parent dialane4 (Al2H4). A computational analysis of this compound is presented.

  20. Both H4K20 mono-methylation and H3K56 acetylation mark transcription-dependent histone turnover in fission yeast

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hanna [Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Kwon, Chang Seob [Department of Chemistry and Biology, Korea Science Academy of KAIST, Busan, 614-822 (Korea, Republic of); Choi, Yoonjung, E-mail: jjungii@kaist.ac.kr [Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Lee, Daeyoup, E-mail: daeyoup@kaist.ac.kr [Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of)

    2016-08-05

    Nucleosome dynamics facilitated by histone turnover is required for transcription as well as DNA replication and repair. Histone turnover is often associated with various histone modifications such as H3K56 acetylation (H3K56Ac), H3K36 methylation (H3K36me), and H4K20 methylation (H4K20me). In order to correlate histone modifications and transcription-dependent histone turnover, we performed genome wide analyses for euchromatic regions in G2/M-arrested fission yeast. The results show that transcription-dependent histone turnover at 5′ promoter and 3′ termination regions is directly correlated with the occurrence of H3K56Ac and H4K20 mono-methylation (H4K20me1) in actively transcribed genes. Furthermore, the increase of H3K56Ac and H4K20me1 and antisense RNA production was observed in the absence of the histone H3K36 methyltransferase Set2 and histone deacetylase complex (HDAC) that are involved in the suppression of histone turnover within the coding regions. These results together indicate that H4K20me1 as well as H3K56Ac are bona fide marks for transcription-dependent histone turnover in fission yeast.

  1. Occurrence of major whey proteins in the pH 4.6 insoluble protein fraction from UHT-treated milk.

    Science.gov (United States)

    Pizzano, Rosa; Manzo, Carla; Nicolai, Maria Adalgisa; Addeo, Francesco

    2012-08-15

    A clear picture of the protein rearrangement in milk following UHT-treatment was drawn by a comparative analysis of the pH 4.6 soluble protein fraction (SPF) and the pH 4.6 insoluble protein fraction (IPF) recovered from raw and UHT-treated milk samples. The two protein fractions were analyzed by mono- or bidimensional gel electrophoresis under reducing and nonreducing conditions, and protein bands were identified by specific immunostaining. Results showed that bovine serum albumin, β-lactoglobulin, and, to a lesser extent, α-lactalbumin coprecipitated with caseins in UHT-treated milk samples at pH 4.6. These proteins were almost exclusively involved in high molecular weight aggregates held together by disulfide bonds. Partition of α-lactalbumin and bovine serum albumin in the protein fractions obtained upon acidification of milk at pH 4.6 was evaluated by competitive immunoassays. The ELISA-based results suggested the possibility of using pH 4.6 insoluble α-lactalbumin and bovine serum albumin, in addition to pH 4.6 insoluble β-lactoglobulin, as indicators of the intensity of the heat treatment applied to milk.

  2. The presence of B7-H4+ macrophages and CD25+CD4+ and FOXP3+ regulatory T cells in the microenvironment of nasal polyps - a preliminary report.

    Directory of Open Access Journals (Sweden)

    P Strek

    2011-04-01

    Full Text Available The nasal polyp (NP seems to represent the end-stage of longstanding inflammation in patients with chronic rhinosinusitis. The aim of our study has been to evaluate the presence of two regulatory cell populations in the microenvironment of NP: CD4+CD25high Foxp3+ (Treg cells and B7-H4-expressing macrophages. Treg cells are actively able to inhibit T lymphocytes, while the population of B7-H4-expressing macrophages has recently been described as characterized by a regulatory function similar to that of Treg cells. For our study, we evaluated 14 NP tissue samples. The samples were divided into two main groups, eosinophilic (NP and lymphocytic (NP, according to the predominant type of immune cell infiltration. The presence of Treg cells and B7-H4 positive macrophages in the samples was analyzed by FACS. Treg cells and B7-H4-expressing macrophages were identified in all the examined nasal polyps. The percentages of both Treg cells and of B7H4 positive cells found in the eosinophilic nasal polyps were higher than those found in the lymphocytic nasal polyps. Treg cells and B7H4+ macrophage subpopulations were present in the NP microenvironment and the alterations in their percentages were related to a distinct pattern of immune cell infiltration.

  3. First principles study of hydrogen storage material NaBH4 and LiAlH4 compounds: electronic structure and optical properties

    Science.gov (United States)

    Ghellab, T.; Charifi, Z.; Baaziz, H.; Uğur, Ş.; Uğur, G.; Soyalp, F.

    2016-04-01

    A comprehensive study of structure, phase stability, optical and electronic properties of LiAlH4 and NaBH4 light-metal hydrides is presented. The calculations are carried out within density functional theory using the full potential linear augmented plane wave method. The exchange-correlation potential is treated within the local density approximation and the generalized gradient approximation (GGA) to calculate the total energy. Furthermore, the Engel-Vosko GGA approach is employed to compute electronic and optical properties such as reflectivity spectra. The phases α, β and γ of LiAlH4 and NaBH4 hydrides are investigated, the phase transition from the β to the high-pressure γ phase is determined for NaBH4 and is accompanied by a 1% volume decrease. For LiAlH4, no phase transition is detected. The materials under consideration are classified as wide band gap compounds. From the analysis of the structures at different phases, it is deduced that the hydrides show strong covalent interaction between B (Al) and H in the [BH4]- ([AlH4]-) anions and ionic bonding character between [BH4]- and Na+ for NaBH4, and [AlH4]- and Li+ for LiAlH4. The complex dielectric function, absorption coefficient and the reflectivity spectra are also computed and analyzed in different phases.

  4. Ganglioside and related-sphingolipid profiles are altered in a cellular model of Alzheimer's disease.

    Science.gov (United States)

    Noel, Anastasia; Ingrand, Sabrina; Barrier, Laurence

    2017-06-01

    Sphingolipid-related issues are increasingly discussed to contribute to the neuropathological process of Alzheimer's disease (AD). In this study, gangliosides and related-sphingolipids (ceramides, neutral glycosphingolipids and sphingomyelins) were analyzed in neuroglioma (H4) cells expressing the Swedish mutation of the human amyloid precursor protein (H4APPsw) and compared with those of wild-type control H4 cells. These cells were chosen since H4APPsw cells were previously reported to reproduce well some essential features of AD. We found that H4APPsw cells exhibited a striking elevation of the simplest ganglioside GM3, an abnormality that was consistently reported in AD patients and animal models of AD. Concomitantly, the levels of both lactosylceramide (the immediate metabolic precursor of GM3) and ganglioside GD1a increased, suggesting a deregulation in the biosynthesis of gangliosides in the H4APPsw cells. Moreover, while the total ceramide level remained unaltered in H4APPsw cells, a shift in ceramide composition from long chain - to very long chain fatty acid-ceramide species was recorded. Because sphingolipid alterations occurring in H4APPsw cells were similar to those observed in transgenic mice and in human brains, this cellular model might be useful to further explore the complex role of sphingolipids in AD pathogenesis. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  5. Compuestos perazufrados de platino(II) con ditioéteres y tiolatos fluorados. Estructuras cristalinas de [Pt(SC6F5)2 (p-C6H4FSCH2CH2-p-SC6H4F)], [Pt(p-SC6HF4)...

    OpenAIRE

    Jorge Bautista; Agusti Bertran; Sylvain Bernès; Ubaldo Duran; Hugo Torrens

    2003-01-01

    En este articulo se describen la síntesis y caracterización de los compuestos cis-[PtCl2(RfSCH2CH2SRf)], Rf = C6F5, p-SC6HF4, o-SC6H4F, m-SC6H4F, p-SC6H4F, m-SC6H4(CF3), y las reacciones de estos compuestos con (SC6F5)– y (p-SC6HF4)– que generan cis- [Pt(SC6F5)2(RfSCH2CH2SRf)] y cis-[Pt(p-SC6HF4) 2(RfSCH2CH2 SRf)], Rf = o-SC6H4F, m-SC6H4F, p-SC6H4F, m-SC6H4(CF3). Para estos compuestos, los datos de RMN de 19F obtenidos a diferentes temperaturas, muestran la presencia e interconversion de isóm...

  6. Intersystem crossing and dynamics in O(3P) + C2H4 multichannel reaction: experiment validates theory.

    Science.gov (United States)

    Fu, Bina; Han, Yong-Chang; Bowman, Joel M; Angelucci, Luca; Balucani, Nadia; Leonori, Francesca; Casavecchia, Piergiorgio

    2012-06-19

    The O((3)P) + C(2)H(4) reaction, of importance in combustion and atmospheric chemistry, stands out as a paradigm reaction involving triplet- and singlet-state potential energy surfaces (PESs) interconnected by intersystem crossing (ISC). This reaction poses challenges for theory and experiments owing to the ruggedness and high dimensionality of these potentials, as well as the long lifetimes of the collision complexes. Primary products from five competing channels (H + CH(2)CHO, H + CH(3)CO, H(2) + CH(2)CO, CH(3) + HCO, CH(2) + CH(2)O) and branching ratios (BRs) are determined in crossed molecular beam experiments with soft electron-ionization mass-spectrometric detection at a collision energy of 8.4 kcal/mol. As some of the observed products can only be formed via ISC from triplet to singlet PESs, from the product BRs the extent of ISC is inferred. A new full-dimensional PES for the triplet state as well as spin-orbit coupling to the singlet PES are reported, and roughly half a million surface hopping trajectories are run on the coupled singlet-triplet PESs to compare with the experimental BRs and differential cross-sections. Both theory and experiment find almost equal contributions from the two PESs to the reaction, posing the question of how important is it to consider the ISC as one of the nonadiabatic effects for this and similar systems involved in combustion chemistry. Detailed comparisons at the level of angular and translational energy distributions between theory and experiment are presented for the two primary channel products, CH(3) + HCO and H + CH(2)CHO. The agreement between experimental and theoretical functions is excellent, implying that theory has reached the capability of describing complex multichannel nonadiabatic reactions.

  7. Cloning and Functional Analysis of Histones H3 and H4 in Nuclear Shaping during Spermatogenesis of the Chinese Mitten Crab, Eriocheir sinensis.

    Directory of Open Access Journals (Sweden)

    Jiang-Li Wu

    Full Text Available During spermatogenesis in most animals, the basic proteins associated with DNA are continuously changing and somatic-typed histones are partly replaced by sperm-specific histones, which are then successively replaced by transition proteins and protamines. With the replacement of sperm nuclear basic proteins, nuclei progressively undergo chromatin condensation. The Chinese Mitten Crab (Eriocheir sinensis is also known as the hairy crab or river crab (phylum Arthropoda, subphylum Crustacea, order Decapoda, and family Grapsidae. The spermatozoa of this species are aflagellate, and each has a spherical acrosome surrounded by a cup-shaped nucleus, peculiar to brachyurans. An interesting characteristic of the E. sinensis sperm nucleus is its lack of electron-dense chromatin. However, its formation is not clear. In this study, sequences encoding histones H3 and H4 were cloned by polymerase chain reaction amplification. Western blotting indicated that H3 and H4 existed in the sperm nuclei. Immunofluorescence and ultrastructural immunocytochemistry demonstrated that histones H3 and H4 were both present in the nuclei of spermatogonia, spermatocytes, spermatids and mature spermatozoa. The nuclear labeling density of histone H4 decreased in sperm nuclei, while histone H3 labeling was not changed significantly. Quantitative real-time PCR showed that the mRNA expression levels of histones H3 and H4 were higher at mitotic and meiotic stages than in later spermiogenesis. Our study demonstrates that the mature sperm nuclei of E. sinensis contain histones H3 and H4. This is the first report that the mature sperm nucleus of E. sinensis contains histones H3 and H4. This finding extends the study of sperm histones of E. sinensis and provides some basic data for exploring how decapod crustaceans form uncondensed sperm chromatin.

  8. The CTX-M-15-producing Escherichia coli clone O25b: H4-ST131 has high intestine colonization and urinary tract infection abilities.

    Directory of Open Access Journals (Sweden)

    Sophie Vimont

    Full Text Available Increasing numbers of pyelonephritis-associated uropathogenic Escherichia coli (UPEC are exhibiting high resistance to antibiotic therapy. They include a particular clonal group, the CTX-M-15-producing O25b:H4-ST131 clone, which has been shown to have a high dissemination potential. Here we show that a representative isolate of this E. coli clone, referred to as TN03, has enhanced metabolic capacities, acts as a potent intestine- colonizing strain, and displays the typical features of UPEC strains. In a modified streptomycin-treated mouse model of intestinal colonization where streptomycin was stopped 5 days before inoculation, we show that TN03 outcompetes the commensal E. coli strains K-12 MG1655, IAI1, and ED1a at days 1 and 7. Using an experimental model of ascending UTI in C3H/HeN mice, we then show that TN03 colonized the urinary tract. One week after the transurethral inoculation of the TN03 isolates, the bacterial loads in the bladder and kidneys were significantly greater than those of two other UPEC strains (CFT073 and HT7 belonging to the same B2 phylogenetic group. The differences in bacterial loads did not seem to be directly linked to differences in the inflammatory response, since the intrarenal expression of chemokines and cytokines and the number of polymorphonuclear neutrophils attracted to the site of inflammation was the same in kidneys colonized by TN03, CFT073, or HT7. Lastly, we show that in vitro TN03 has a high maximum growth rate in both complex (Luria-Bertani and human urine and minimum media. In conclusion, our findings indicate that TN03 is a potent UPEC strain that colonizes the intestinal tract and may persist in the kidneys of infected hosts.

  9. Mainstreams of horizontal gene exchange in enterobacteria: consideration of the outbreak of enterohemorrhagic E. coli O104:H4 in Germany in 2011.

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    Oliver Bezuidt

    Full Text Available BACKGROUND: Escherichia coli O104:H4 caused a severe outbreak in Europe in 2011. The strain TY-2482 sequenced from this outbreak allowed the discovery of its closest relatives but failed to resolve ways in which it originated and evolved. On account of the previous statement, may we expect similar upcoming outbreaks to occur recurrently or spontaneously in the future? The inability to answer these questions shows limitations of the current comparative and evolutionary genomics methods. PRINCIPAL FINDINGS: The study revealed oscillations of gene exchange in enterobacteria, which originated from marine γ-Proteobacteria. These mobile genetic elements have become recombination hotspots and effective 'vehicles' ensuring a wide distribution of successful combinations of fitness and virulence genes among enterobacteria. Two remarkable peculiarities of the strain TY-2482 and its relatives were observed: i retaining the genetic primitiveness by these strains as they somehow avoided the main fluxes of horizontal gene transfer which effectively penetrated other enetrobacteria; ii acquisition of antibiotic resistance genes in a plasmid genomic island of β-Proteobacteria origin which ontologically is unrelated to the predominant genomic islands of enterobacteria. CONCLUSIONS: Oscillations of horizontal gene exchange activity were reported which result from a counterbalance between the acquired resistance of bacteria towards existing mobile vectors and the generation of new vectors in the environmental microflora. We hypothesized that TY-2482 may originate from a genetically primitive lineage of E. coli that has evolved in confined geographical areas and brought by human migration or cattle trade onto an intersection of several independent streams of horizontal gene exchange. Development of a system for monitoring the new and most active gene exchange events was proposed.

  10. A Primary Test of EHEC O104:H4and EHEC O157:H7in Certain Kinds of Food in Wuhan,China%A Primary Test of EHEC O 104: H4 and EHEC O 157: H7 in Certain Kinds of Food in Wuhan, China

    Institute of Scientific and Technical Information of China (English)

    Wei Hechen; Xiong Yan

    2012-01-01

    Objective:This paper provided preliminary description of food contamination derived from Enterohemorrhagic Escherichia coli (EHEC)O104:H4 and EHEC O157:H7 in Wuhan in June 2011.Methods:47 food samples,including vegetables and meat,were subjectively sampled from some restaurants.PCR assays were used to detect EHEC O104:H4 and EHEC O157:H7.Results:The PCR results showed that none of the samples were positive for either EHEC O104:H4 or EHEC O 157:H7.Conclusion:Although large outbreaks of gastroenteritis and the hemolytic uremic syndrome caused by EHEC O104:H4 had occurred in some European countries,China has had few outbreaks associated with EHEC O104:H4.This shows that food supply is relatively safe in China.Nevertheless,many ongoing problems of food safety in China are still not solved showing the necessity of further studies on food safety.

  11. Intrahost milieu modulates production of outer membrane vesicles, vesicle-associated Shiga toxin 2a and cytotoxicity in Escherichia coli O157:H7 and O104:H4.

    Science.gov (United States)

    Bauwens, Andreas; Kunsmann, Lisa; Marejková, Monika; Zhang, Wenlan; Karch, Helge; Bielaszewska, Martina; Mellmann, Alexander

    2017-07-04

    Outer membrane vesicles (OMVs) are important virulence tools of enterohaemorrhagic Escherichia coli (EHEC), but other biological functions of these nanostructures are unknown. We tested the hypothesis that modulation of OMV production enables EHEC to resist the intrahost environment during infection by investigating if simulated human gastrointestinal conditions affect OMV production in EHEC O157:H7 and O104:H4. All the conditions tested including a low pH, simulated ileal and colonic media, presence of mucin, intestinal epithelial cell lysate or antimicrobial peptides, as well as iron limitation, significantly increased OMV production by these pathogens. Accordingly, a maximum vesiculation in EHEC O104:H4 was observed immediately after its isolation from a patient's intestine, and rapidly decreased during passages in vitro. Most of the simulated intrahost conditions also upregulated the OMV-associated Shiga toxin 2a (Stx2a), the major EHEC virulence factor, and, as a result, OMV cytotoxicity. The data indicates that upregulation of OMV production by the human gastrointestinal milieu contributes to EHEC survival and adaptation within the host during infection. Moreover, the intrahost increase of vesiculation and OMV-associated Stx2a may augment EHEC virulence. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. A comparison of Shiga-toxin 2 bacteriophage from classical enterohemorrhagic Escherichia coli serotypes and the German E. coli O104:H4 outbreak strain.

    Directory of Open Access Journals (Sweden)

    Chad R Laing

    Full Text Available Escherichia coli O104:H4 was associated with a severe foodborne disease outbreak originating in Germany in May 2011. More than 4000 illnesses and 50 deaths were reported. The outbreak strain was a typical enteroaggregative E. coli (EAEC that acquired an antibiotic resistance plasmid and a Shiga-toxin 2 (Stx2-encoding bacteriophage. Based on whole-genome phylogenies, the O104:H4 strain was most closely related to other EAEC strains; however, Stx2-bacteriophage are mobile, and do not necessarily share an evolutionary history with their bacterial host. In this study, we analyzed Stx2-bacteriophage from the E. coli O104:H4 outbreak isolates and compared them to all available Stx2-bacteriophage sequences. We also compared Stx2 production by an E. coli O104:H4 outbreak-associated isolate (ON-2011 to that of E. coli O157:H7 strains EDL933 and Sakai. Among the E. coli Stx2-phage sequences studied, that from O111:H- strain JB1-95 was most closely related phylogenetically to the Stx2-phage from the O104:H4 outbreak isolates. The phylogeny of most other Stx2-phage was largely concordant with their bacterial host genomes. Finally, O104:H4 strain ON-2011 produced less Stx2 than E. coli O157:H7 strains EDL933 and Sakai in culture; however, when mitomycin C was added, ON-2011 produced significantly more toxin than the E. coli O157:H7 strains. The Stx2-phage from the E. coli O104:H4 outbreak strain and the Stx2-phage from O111:H- strain JB1-95 likely share a common ancestor. Incongruence between the phylogenies of the Stx2-phage and their host genomes suggest the recent Stx2-phage acquisition by E. coli O104:H4. The increase in Stx2-production by ON-2011 following mitomycin C treatment may or may not be related to the high rates of hemolytic uremic syndrome associated with the German outbreak strain. Further studies are required to determine whether the elevated Stx2-production levels are due to bacteriophage or E. coli O104:H4 host related factors.

  13. H4N8 subtype avian influenza virus isolated from shorebirds contains a unique PB1 gene and causes severe respiratory disease in mice

    Science.gov (United States)

    Bui, Vuong N.; Ogawa, Haruko; Xininigen; Karibe, Kazuji; Matsuo, Kengo; Awad, Sanaa S. A.; Minoungou, Germaine L.; Yoden, Satoshi; Haneda, Hiroaki; Ngo, Lai H.; Tamaki, Shio; Yamamoto, Yu; Nakamura, Kikuyasu; Saito, Keisuke; Watanabe, Yukiko; Runstadler, Jonathan; Huettman, Falk; Happ, George M.; Imai, Kunitoshi

    2011-01-01

    H4N8 subtype avian influenza viruses were isolated from shorebirds in eastern Hokkaido. All the isolates shared >99.7% nucleotide homology, and all the viral genes except for PB1 were highly related to those of A/red-necked stint/Australia/1/04. Thus, the isolates were regarded as PB1 reassortants. The most similar PB1 gene was identified in A/mallard/New Zealand/1615-17/04 (H4N6) with nucleotide homology of 90.9%. BALB/c mice intranasally inoculated with the H4N8 isolates developed severe respiratory disease, which eventually led to death in some mice. Virus was isolated from the lungs, and viral antigen was detected in the lungs with pneumonia. Other H4 subtype viruses tested did not cause any symptoms in mice, although these viruses were also isolated from the lungs. The PB2 gene of the H4N8 isolates contains K482R, but not the E627K or D701N substitutions. The PB1-F2 gene of the isolates consists of a 101-amino acid unique sequence, but lacks the N66S mutation. PMID:22192630

  14. Preparation and Catalytic Activity of a Novel Nanocrystalline ZrO2 @C Composite for Hydrogen Storage in NaAlH4.

    Science.gov (United States)

    Zhang, Xin; Wu, Ruyan; Wang, Zeyi; Gao, Mingxia; Pan, Hongge; Liu, Yongfeng

    2016-12-19

    Sodium alanate (NaAlH4 ) has attracted intense interest as a prototypical high-density hydrogen-storage material. However, poor reversibility and slow kinetics limit its practical applications. Herein, a nanocrystalline ZrO2 @C catalyst was synthesized by using Uio-66(Zr) as a precursor and furfuryl alcohol (FA) as a carbon source. The as-synthesized ZrO2 @C exhibits good catalytic activity for the dehydrogenation and hydrogenation of NaAlH4 . The NaAlH4 -7 wt % ZrO2 @C sample released hydrogen starting from 126 °C and reabsorbed it starting from 54 °C, and these temperatures are lower by 71 and 36 °C, respectively, relative to pristine NaAlH4 . At 160 °C, approximately 5.0 wt % of hydrogen was released from the NaAlH4 -7 wt % ZrO2 @C sample within 250 min, and the dehydrogenation product reabsorbed approximately 4.9 wt % within 35 min at 140 °C and 100 bar of hydrogen. The catalytic function of the Zr-based active species is believed to contribute to the significantly reduced operating temperatures and enhanced kinetics.

  15. Facile synthesis of silver nanoparticles-modified PVA/H4SiW12O40 nanofibers-based electrospinning to enhance photocatalytic activity

    Science.gov (United States)

    Sui, Chunhong; Li, Chao; Guo, Xiaohong; Cheng, Tiexin; Gao, Yukun; Zhou, Guangdong; Gong, Jian; Du, Jianshi

    2012-07-01

    Regarding poly(vinyl alcohol)/silicotungstic acid (PVA/H4SiW12O40) gel as precursor, the silver nanoparticles (NPs) were selectively deposited on the surface of the PVA/H4SiW12O40 nanofibers by using electrospinning and photoreduction methods. X-ray photoelectron spectroscopy, Fourier transformation infrared spectroscopy, and UV-vis diffuse reflectance spectroscopy were used to affirm the structure and formation of tri-component nanohybrids. Field environmental scanning electron microscope and transmission electron microscopy indicate that the average diameter of silver NPs was changed from 25 nm to 50 nm, with decreasing the relative concentration of SiW12 in the as-electrospun nanofibers. The nanocomposites exhibit excellent photocatalytic activity in degradation of Rhodamine B. This result arises from the synergistic effects and the large specific surface areas of Ag/PVA/H4SiW12O40 tri-component nanohybrids.

  16. Tungsten phosphanylarylthiolato complexes [W{PhP(2-SC6H4)2-kappa3S,S',P} 2] and [W{P(2-SC6H4)3-kappa4S,S',S",P}2]: synthesis, structures and redox chemistry.

    Science.gov (United States)

    Hildebrand, Alexandra; Lönnecke, Peter; Silaghi-Dumitrescu, Luminita; Hey-Hawkins, Evamarie

    2008-09-14

    PhP(2-SHC6H4)2 (PS2H2) reacts with WCl6 with reduction of tungsten to give the air-sensitive tungsten(IV) complex [W{PhP(2-SC6H4)2-kappa(3)S,S',P}2] (1). 1 is oxidised in air to [WO{PhPO(2-SC6H4)2-kappa(3)S,S',O}{PhP(2-SC6H4)2-kappa(3)S,S',P}] (2). The attempted synthesis of 2 by reaction of 1 with iodosobenzene as oxidising agent was unsuccessful. [W{P(2-SC6H4)3-kappa(4)S,S',S",P}2] (3) was formed in the reaction of P(2-SHC6H4)3 (PS3H3) with WCl6. The W(VI) complex 3 contains two PS3(3-) ligands, each coordinated in a tetradentate fashion resulting in a tungsten coordination number of eight. The reaction of 3 with AgBF4 yields the dinuclear tungsten complex [W2{P(2-SC6H4)3-kappa(4)S,S',S",P}3]BF4 (4). Complexes 1-4 were characterised by spectral methods and X-ray structure determination.

  17. A single substitution in 5'-untranslated region of plcB is involved in enhanced broad-range phospholipase C activity in Listeria monocytogenes strain H4

    Institute of Scientific and Technical Information of China (English)

    Fan Bai; Jianshun Chen; Qiaomiao Chen; Xiaokai Luo; Weihuan Fang; Lingli Jiang

    2011-01-01

    To examine whether the in vitro phospholipase activity in Listeria monocytogenes strain H4 was due to two nucleotide mutations (C to T at position -26 and A to G at position + 1) in plcB or resulted from regulatory activation, two mutants H4-plcB-ml (single mutation at position -26) and H4-plcB-m2 (substitution at both positions) were constructed by site-directed mutagenesis. It was found that the two mutants had significantly lower transcription of plcB than their parent strain H4 and did not show phospho-Hpase activity on the egg yolk agar, implying that the apparent phospholipase activity of strain H4 could be related to single substitution at position -26 ofplcB, most probably by its 5t-untranslated region (5'-UTR) regulation mechanism. Tn917-based transposon mutagenesis generated eight L. monocytogenes mutants lacking phospholipase activity among 560 mutant candidates. Seven mutants had transposon insertion into prfA (encoding positive regulatory factor A) open reading frame, whereas only one mutant (WF-L127) was inserted into the P1 promoter region ofprfA (prfAP1). Transcription of major virulence genes was significantly lower in both types of mutants than in their parent strain H4. Disruption of prfAP1 in WFL127 abolished its phospholipase C activity but did not change its hemolytic phenotype, indicating that plcB was more dependent on prfA regulation than hly. Taken together, this study presents some evidence for the regulation ofplcB expression by its 5'-UTR mechanism.

  18. Nano-electrospray tandem mass spectrometric analysis of the acetylation state of histones H3 and H4 in stationary phase in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Patterton Hugh G

    2011-07-01

    Full Text Available Abstract Background The involvement of histone acetylation in facilitating gene expression is well-established, particularly in the case of histones H3 and H4. It was previously shown in Saccharomyces cerevisiae that gene expression was significantly down-regulated and chromatin more condensed in stationary phase compared to exponential phase. We were therefore interested in establishing the acetylation state of histone H3 and H4 in stationary and in exponential phase, since the regulation of this modification could contribute to transcriptional shut-down and chromatin compaction during semi-quiescence. Results We made use of nano-spray tandem mass spectrometry to perform a precursor ion scan to detect an m/z 126 immonium ion, diagnostic of an Nε-acetylated lysine residue that allowed unambiguous identification of acetylated as opposed to tri-methylated lysine. The fragmentation spectra of peptides thus identified were searched with Mascot against the Swiss-Prot database, and the y-ion and b-ion fragmentation series subsequently analyzed for mass shifts compatible with acetylated lysine residues. We found that K9, K14 and K36 of histone H3 and K12 and K16 of histone H4 were acetylated in exponential phase (bulk histones, but could not detect these modifications in histones isolated from stationary phase cells at the sensitivity level of the mass spectrometer. The corresponding un-acetylated peptides were, however, observed. A significantly higher level of acetylation of these residues in exponential phase was confirmed by immuno-blotting. Conclusion H4K16 acetylation was previously shown to disrupt formation of condensed chromatin in vitro. We propose that de-acetylation of H4K16 allowed formation of condensed chromatin in stationary phase, and that acetylation of H3K9, H3K14, H3K36, and H4K12 reflected the active transcriptional state of the yeast genome in exponential phase.

  19. Molecular epidemiology of a household outbreak of Shiga-toxin-producing Escherichia coli in Poland due to secondary transmission of STEC O104:H4 from Germany.

    Science.gov (United States)

    Januszkiewicz, Aleksandra; Szych, Jolanta; Rastawicki, Waldemar; Wołkowicz, Tomasz; Chróst, Anna; Leszczyńska, Beata; Kuźma, Elżbieta; Roszkowska-Blaim, Maria; Gierczyński, Rafał

    2012-04-01

    We characterized two STEC O104 : H4 clinical isolates collected in Poland from a 7-year-old boy with haemolytic uraemic syndrome (HUS) and his nanny. This household outbreak began on 29 May 2011. Because of its time-frame, the outbreak was assumed to be part of the international STEC O104 : H4 outbreak that arose in Germany in May 2011. The two Polish isolates were Shiga-toxin-producing Escherichia coli (stx2 lpf) with enteroaggregative E. coli pathotype (aggR aap aggA), thereby sharing the unique virulence properties of the epidemic STEC O104 : H4 strain from the international outbreak. The Polish isolates were multi-drug resistant and carried bla(TEM), strA, strB, tetA, sul1 and sul2 markers together with the bla(CTX-M-15) gene for CTX-M-15 extended-spectrum β-lactamase. PFGE patterns and plasmid profiles of the Polish isolates and the epidemic STEC O104 : H4 strain corresponded closely. This finding suggested an epidemiological link between the Polish STEC O104 : H4 isolates and the international outbreak. Retrospective serological investigations proved person-to-person transmission of the epidemic STEC O104 : H4 strain from a father who had visited Dortmund, Germany, to his 7-year-old son in Giżycko, Poland. To the best of our knowledge, this is the first report of household transmission of Shiga-toxin-producing E. coli in Poland.

  20. Histone H2A and H4 N-terminal tails are positioned by the MEP50 WD repeat protein for efficient methylation by the PRMT5 arginine methyltransferase.

    Science.gov (United States)

    Burgos, Emmanuel S; Wilczek, Carola; Onikubo, Takashi; Bonanno, Jeffrey B; Jansong, Janina; Reimer, Ulf; Shechter, David

    2015-04-10

    The protein arginine methyltransferase PRMT5 is complexed with the WD repeat protein MEP50 (also known as Wdr77 or androgen coactivator p44) in vertebrates in a tetramer of heterodimers. MEP50 is hypothesized to be required for protein substrate recruitment to the catalytic domain of PRMT5. Here we demonstrate that the cross-dimer MEP50 is paired with its cognate PRMT5 molecule to promote histone methylation. We employed qualitative methylation assays and a novel ultrasensitive continuous assay to measure enzyme kinetics. We demonstrate that neither full-length human PRMT5 nor the Xenopus laevis PRMT5 catalytic domain has appreciable protein methyltransferase activity. We show that histones H4 and H3 bind PRMT5-MEP50 more efficiently compared with histone H2A(1-20) and H4(1-20) peptides. Histone binding is mediated through histone fold interactions as determined by competition experiments and by high density histone peptide array interaction studies. Nucleosomes are not a substrate for PRMT5-MEP50, consistent with the primary mode of interaction via the histone fold of H3-H4, obscured by DNA in the nucleosome. Mutation of a conserved arginine (Arg-42) on the MEP50 insertion loop impaired the PRMT5-MEP50 enzymatic efficiency by increasing its histone substrate Km, comparable with that of Caenorhabditis elegans PRMT5. We show that PRMT5-MEP50 prefers unmethylated substrates, consistent with a distributive model for dimethylation and suggesting discrete biological roles for mono- and dimethylarginine-modified proteins. We propose a model in which MEP50 and PRMT5 simultaneously engage the protein substrate, orienting its targeted arginine to the catalytic site.

  1. EHEC O104:H4 in Germany 2011: Large outbreak of bloody diarrhea and haemolytic uraemic syndrome by shiga toxin-producing E. coli via contaminated food

    OpenAIRE

    2012-01-01

    In the summer of 2011 Germany experienced one of the largest outbreaks of a food-borne infection caused by enterohaemorrhagic Escherichia coli (EHEC) with the serotype O104:H4. A large number of cases with bloody diarrhea and haemolytic uraemic syndrome (HUS) occurred. Never before was such a high rate of HUS cases observed in an outbreak caused by a food-borne pathogen. The events in Germany caused by EHEC O104:H4 in the summer of 2011 show dramatically how rapidly an infectious agent ...

  2. Electron-Deficient Iron Alkyl Complexes Supported by Diimine Ligand (Ph2CN)(2)C2H4 : Evidence for Reversible Ethylene Binding

    NARCIS (Netherlands)

    Volbeda, Jeroen; Meetsma, Auke; Bouwkamp, Marco W.

    2009-01-01

    Reaction of diimine ligands (Ph2CN)(2)CnH2n (n = 2, a; n = 3, b) with FeCl2 or FeBr2 results in formation of the corresponding high-spin ferrous complexes {Ph2CN)(2)C2H4} FeX2 (1a, X = Cl; 2a, X = Br) and {(Ph2CN)(2)C3H3}FeCl2 (1b). Dialkyl {(Ph2CN)(2)C2H4) Fe(CH2SiMe3)(2) (3a) was prepared by

  3. Selection and characterization of a candidate therapeutic bacteriophage that lyses the Escherichia coli O104:H4 strain from the 2011 outbreak in Germany.

    Directory of Open Access Journals (Sweden)

    Maia Merabishvili

    Full Text Available In 2011, a novel strain of O104:H4 Escherichia coli caused a serious outbreak of foodborne hemolytic uremic syndrome and bloody diarrhea in Germany. Antibiotics were of questionable use and 54 deaths occurred. Candidate therapeutic bacteriophages that efficiently lyse the E. coli O104:H4 outbreak strain could be selected rather easily from a phage bank or isolated from the environment. It is argued that phage therapy should be more considered as a potential armament against the growing threat of (resistant bacterial infections.

  4. Crystal Structure Studies on p-Substitutedbenzenesulphonamides 4-X-C6H4SO2NH2 (X = CH3, NH2 F, Cl or Br)

    Science.gov (United States)

    Thimme Gowda, B.; Jyothi, K.; Kožíšek, Jozef; Fuess, Hartmut

    2003-11-01

    Effect of ring substitution on the crystal structures of p-substitutedbenzenesulphonamides, p-XC6H4SO2NH2 (X = F, Cl, Br, CH3 or NH2) has been studied by determining the crystal structures of 4-chlorobenzenesulphonamide (4-ClC6H4SO2NH2) and 4-bromobenzenesulphonamide (4-BrC6H4SO2NH2) and analyzing the results along with the structures of 4-methylbenzenesulphonamide (4-CH3C6H4SO2NH2), 4-fluorobenzene-sulphonamide (4-FC6H4SO2NH2) and 4-aminobenzenesulphonamide (4-NH2C6H4SO2NH2). The crystal type, space group, formula units and lattice constants in Å of new structures are: (4-ClC6H4SO2NH2); monoclinic, P21/n, Z = 4, a = 6.6276(10), b = 16.219(3), c = 7.5716(10), β = 93.387(14)°; (4-BrC6H4SO2NH2): monoclinic, P 21/n, Z = 4, a = 6.5660(10), b = 16.4630(10), c = 7.6900(10), β = 92.760(10)°. Orientation of the amine group with respect to the phenyl ring is given by the torsion angles C(2)-C(1)-S-N: 70.9° and C(6)-C(1)-S-N: -108.5°. Similarly, the orientation of S, O(1) and O(2) with respect to the ring are given by torsion angles. The comparison of bond lengths and bond angles of 4-fluoro-, 4-chloro-, 4-bromo-, 4-methyl- and 4-amino-benzenesulphonamides reveal that the S-N and C-S bond lengths decrease with the introduction of electron-withdrawing substituents such as F, Cl or Br, while these groups do not have significant effects on the S-O distances. The effect on ring C-C distances was not uniform. Substitution of F, Cl or Br decreases the O-S-N bond angle, but increases the O-S-N, N-S-C(1) and C(3)-C(4)-C(5) bond angles.

  5. Local spin dynamics at low temperature in the slowly relaxing molecular chain [Dy(hfac)3NIT(C6H4OPh)]: A μ+ spin relaxation study

    OpenAIRE

    P. Arosio; M. Corti; Mariani, M; Orsini, F.; Bogani, L.; A. CANESCHI; Lago, J.; Lascialfari, A.

    2015-01-01

    The spin dynamics of the molecular magnetic chain [Dy(hfac)(3){NIT(C6H4OPh)}] were investigated by means of the Muon Spin Relaxation (mu+SR) technique. This system consists of a magnetic lattice of alternating Dy(III) ions and radical spins, and exhibits single-chain-magnet behavior. The magnetic properties of [Dy(hfac)(3){NIT(C6H4OPh)}] have been studied by measuring the magnetization vs. temperature at different applied magnetic fields (H - 5, 3500, and 16500 Oe) and by performing mu+SR exp...

  6. Expression of B7-H4 gene from mouse in eukaryofic system and its suppressive effect on proliferation of lymphocytes cell%小鼠B7-H4基因的真核表达及其对淋巴细胞增殖的影响

    Institute of Scientific and Technical Information of China (English)

    李丽; 胡为民; 王朝莉; 杨致邦

    2012-01-01

    Objective To provide subjects for lucubrating the effect of B7-H4 on T cell activation and graft rejective reaction through cloning and constructing the eukaryotic expression vector encoding the gene of extracellular region of B7-H4 from mouse, and investigate the effect of B7-H4 on the proliferation of lymphocytes in vitro. Method The total RNAs of mouse lung and spleen were extracted and cDNA was transcribed from RNA using RT-PCR technique. The gene of extracellular region nf B7-H4 was amplified according to the template of cDNA by PCR. The amplified cDNA was imported into pGEM-T Easy vector to construct TA-mB7-H4 plasmid. The plasmid was cut by restriction enzyme of XbaⅠ and HindⅢ and was identified by the agarose gel electrophoresis and sequence scanning. Then the mB7-H4 corroborated by sequencing was inserted into the fluorescence expression vector MYC-HIS-EGFP-N after cut by the restriction enzymes to construct B7-H4-EGFP and control-EGFP eukaryotic expression vectors. The recombinant plasmids were transfected into JM109 competence bacteria, and were extracted and identified by the agarose gel electrophoresis and the sequencing after cut with the restriction enzymes. They were transfect-ed into CHO cell through lipofectamine? 2000, and the CHO cell lines expressing stably the fusion protein were obtained through G418 selection. MTT colorimetry was used to assess the effect of B7-H4 on the proliferation of lymphocyte in the culture of lymphocyte from BALB/c or C57 mouse respectively and in co-culture of lymphocyte from both BALB/c and C57 mouse. Result The gene sequences of B7-H4 cDNA cloned from mouse and TA-mB7-H4 constructed were correct by sequencing. The transfective CHO cells slahly expressed the recombinant transmembrane B7-H4 protein. The B7-H4 protein suppressed the lymphocyte proliferation either in the culture of lymphocyte respectively and in co-culture of lymphocyte from BALB/c and C57 mouse. Conclusion The B7-H4 eukaryotic expression vector

  7. Synthesis of Group 4 metal compounds containing cyclopentadienyl ligands with a pendant alkoxide function : Molecular structure of {[eta(5):eta(1)-C5H4(CH2)(2)O]TiCl2}(2) and [eta(5):eta(1)-C5H4(CH2)(3)O]TiCl2

    NARCIS (Netherlands)

    Trouvé, Gwénaëlle; Laske, Dietmar A.; Meetsma, Auke; Teuben, Jan H.

    1996-01-01

    Trimethylsilylcyclopentadiene-siloxy ethers Me(3)SiC(5)H(4)(CH2),OSiMe(3) (n = 2, 3) react with TiCl4 to give (2-(cyclopentadienyl)-eth-1-oxy)titanium dichloride, [[eta(5): eta(1)-C5H4(CH2)(2)O]TiCl2](2) and (3-(cyclopentadienyl)-prop-1-oxy)titanium dichloride [eta(5): eta(1)- C5H4(CH2)(3)O]TiCl2, b

  8. Tris(2-ethylamino)amine ( tren) as template for the elaboration of fluorides: synthesis and crystal structures of [(C 2H 4NH 3) 3NH]·[Zr 3F 16(H 2O)], [(C 2H 4NH 3) 3N] 2·[ZrF 6]·[Zr 2F 12] and [(C 2H 4NH 3) 3N]·[TaF 7]·F

    Science.gov (United States)

    Goreshnik, E.; Leblanc, M.; Maisonneuve, V.

    2004-11-01

    Using tris(2-ethylamino)amine ( tren) as a template, three new fluorides are obtained by solvothermal synthesis: [(C 2H 4NH 3) 3NH]·[Zr 3F 16(H 2O)] ( I), [(C 2H 4NH 3) 3N] 2·[ZrF 6]·[Zr 2F 12] ( II) and [(C 2H 4NH 3) 3N]·[TaF 7]·F ( III). The structure determinations are performed by single crystal technique. The structure of I consists of infinite spiral-like [Zr 3F 16(H 2O)] 4- chains connected by tetraprotonated [ trenH 4] 4+ cations which possess a plane configuration. In II, isolated [ZrF 6] octahedra or [Zr 2F 12] dimers are linked to organic cations by a tridimensional hydrogen bond network. In III, [TaF 7] 2- monocapped trigonal prisms and "isolated" fluoride ions are connected by hydrogen bonds to template moieties. In II and III, every organic moiety is triprotonated [ trenH 3] 3+ with a "spider" configuration. In the tantalum phase, the hydrogen bond network leads to the formation of a layered structure.

  9. Isolation of 1,4-Li(2)-C(6)H(4) and its reaction with [(Ph(3)P)AuCl].

    Science.gov (United States)

    Flower, Kevin R; McGown, A T; Miles, Philip J; Pritchard, Robin G; Warren, John E

    2010-04-14

    The difficulty in generating 1,4-Li2-C6H4 utilising the lithium halogen exchange reaction on 1,4-Br2-C6H4, 1,4-I2-C6H4 and 1-Br-4-I-C6H4 is revisited and only on treatment of 1,4-I2-C6H4 with 2 molar equivalents of n-BuLi can 1,4-Li2-C6H4 1 be isolated in excellent yield. Treatment of 1 with two equivalents of [ClAu(PPh3)] gives [1,4-(Ph3PAu)2-C6H4] 2a in excellent yield. Subsequent treatment of 2a with 2.5 molar equivalents of PPh2Me, PPhMe2 or PMe3 affords the PPh3 substituted compounds [1,4-(LAu)2-C6H4] (L = PPh2Me 2b, PPhMe2 2c, PMe3 2d) in essentially quantitative yields. On treatment of 1,4-Br2-C6H4 or 1-Br-4-I-C6H4 with 2 molar equivalents of n-BuLi only mono-lithiation takes place to give 1-Br-4-Li-C6H4 3 as shown through the isolation of essentially 1:1 molar equivalents of Ph2PC6H4-4-Br and Ph2PBu on treatment with 2 molar equivalents of ClPPh2. Treatment of 3, prepared by lithium/iodine exchange on 1-Br-4-I-C6H4, with [ClAu(PPh3)] affords [(Ph3P)Au(C6H4-4-Br)] 4 as expected and in addition [(Ph3P)Au(n-Bu)(C6H4-4-Br)2] 5, indicating the straightforward chloride/aryl exchange at gold may proceed in competition with oxidative addition of the n-BuI, generated in the initial lithium/iodine exchange reaction, to some aurate complex Li[Au(C6H4-4-Br)2] 6 formed in situ followed by reductive elimination of Br-C6H4-4-n-Bu in a manner that mimics lithium diorganocuprate chemistry. All of the gold-containing compounds have been spectroscopically characterised by 1H and 31P-{1H} NMR and in addition compounds 2a-d and 5 by single crystal X-ray diffraction studies. The solid state structures observed for 2a-d are dictated by non-conventional hydrogen bonding and the packing requirements of the phosphine ligands. For 2a and 2b there is no close Au...Au approach, however for 2c and 2d the reduction in the number of phenyl rings allows the formation of Au...Au contacts. For 2c and 2d the extended structures appear to be helical chains with Au...Au contact parameters of 3

  10. 40 CFR 721.3635 - Octadecanoic acid, ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Octadecanoic acid, ester with 1,2..., ester with 1,2-propanediol, phosphate, anhydride with silicic acid (H4SiO4). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as octadecanoic acid,...

  11. Genome sequence of E. coli O104:H4 leads to rapid development of a targeted antimicrobial agent against this emerging pathogen.

    Science.gov (United States)

    A recent widespread outbreak of Escherichia coli O104:H4 in Germany demonstrates the dynamic nature of emerging and re-emerging food-borne pathogens, particularly STECs and related pathogenic E. coli. Rapid genomic sequencing and public availability of these data from the German outbreak strain allo...

  12. Ultrafine Nanocrystalline CeO2@C-Containing NaAlH4 with Fast Kinetics and Good Reversibility for Hydrogen Storage.

    Science.gov (United States)

    Zhang, Xin; Liu, Yongfeng; Wang, Ke; Li, You; Gao, Mingxia; Pan, Hongge

    2015-12-21

    A nanocrystalline CeO2@C-containing NaAlH4 composite is successfully synthesized in situ by hydrogenating a NaH-Al mixture doped with CeO2@C. Compared with NaAlH4 , the as-prepared CeO2@C-containing NaAlH4 composite, with a minor amount of excess Al, exhibits significantly improved hydrogen storage properties. The dehydrogenation onset temperature of the hydrogenated [NaH-Al-7 wt % CeO2@C]-0.04Al sample is 77 °C lower than that of the pristine sample because of a reduced kinetic barrier. More importantly, the dehydrogenated sample absorbs ∼4.7 wt % hydrogen within 35 min at 100°C and 10 MPa of hydrogen. Compositional and structural analyses reveal that CeO2 is converted to CeH2 during ball milling and that the newly formed CeH2 works with the excess of Al to synergistically improve the hydrogen storage properties of NaAlH4. Our findings will aid in the rational design of novel catalyst-doped complex hydride systems with low operating temperatures, fast kinetics, and long-term cyclability.

  13. Structural Insights into the Association of Hif1 with Histones H2A-H2B Dimer and H3-H4 Tetramer.

    Science.gov (United States)

    Zhang, Mengying; Liu, Hejun; Gao, Yongxiang; Zhu, Zhongliang; Chen, Zijun; Zheng, Peiyi; Xue, Lu; Li, Jixi; Teng, Maikun; Niu, Liwen

    2016-10-04

    Histone chaperones are critical for guiding specific post-transcriptional modifications of histones, safeguarding the histone deposition (or disassociation) of nucleosome (dis)assembly, and regulating chromatin structures to change gene activities. HAT1-interacting factor 1 (Hif1) has been reported to be an H3-H4 chaperone and to be involved in telomeric silencing and nucleosome (dis)assembly. However, the structural basis for the interaction of Hif1 with histones remains unknown. Here, we report the complex structure of Hif1 binding to H2A-H2B for uncovering the chaperone specificities of Hif1 on binding to both the H2A-H2B dimer and the H3-H4 tetramer. Our findings reveal that Hif1 interacts with the H2A-H2B dimer and the H3-H4 tetramer via distinct mechanisms, suggesting that Hif1 is a pivotal scaffold on alternate binding of H2A-H2B and H3-H4. These specificities are conserved features of the Sim3-Hif1-NASP interrupted tetratricopeptide repeat proteins, which provide clues for investigating their potential roles in nucleosome (dis)assembly. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Interactive effects of temperature, pH, and water activity on the growth kinetics of Shiga-toxin producing Escherichia coli O104:H4

    Science.gov (United States)

    The risk of non-O157 Escherichia coli strains has become a growing public health concern. Several studies characterized the behavior of E. coli O157:H7; however, no reports are available on the influence of multiple factors on E. coli O104:H4. This study examined the effects and interactions of tem...

  15. One-pot solvothermal synthesis of ZnSe·xN2H4/GS and ZnSe/N-GS and enhanced visible-light photocatalysis.

    Science.gov (United States)

    Liu, Bitao; Tian, Liangliang; Wang, Yuhua

    2013-09-11

    Doped-graphene has attracted considerable attention in many fields because doping element can alter the electrical properties of graphene. In this paper, we synthesized ZnSe·xN2H4/graphene (ZnSe·xN2H4/GS) and ZnSe/nitrogen-doped graphene (ZnSe/N-GS) nanocomposites with p-n junctions via one-pot solvothermal process. The structure, morphologies and catalytic performance of the ZnSe·xN2H4/GS and ZnSe/N-GS are characterized by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), and cathodoluminescence spectrum (CL), respectively. Our experiments show that the as-prepared nanocomposites ZnSe·xN2H4/GS and ZnSe/N-GS exhibit remarkably enhanced photocatalytic activities for methylene blue (MB) dye under visible light irradiation. Even importantly, ZnSe/N-GS would make this degradation process more effective. Overall, this facile and catalyst-free synthesize method in this work could provide new insights into the fabrication of other composites based on doped graphene with high performance photocatalysts, which show their potential applications in producing of hydrogen through water splitting, environmental protection issues.

  16. Therapeutic concentrations of antibiotics inhibit Shiga toxin release from enterohemorrhagic E. coli O104:H4 from the 2011 German outbreak

    Directory of Open Access Journals (Sweden)

    Corogeanu Diana

    2012-08-01

    Full Text Available Abstract Background The shiga toxin-producing E. coli (STEC O104:H4 caused a major outbreak in Germany in spring 2011. STEC are usually susceptible to common antibiotics. However, antibiotic treatment of STEC-infected patients is not recommended because STEC may enhance production and release of shiga toxins (STX in response to antibiotics, which eventually enhances the frequency and severity of clinical symptoms, including haemolytic uraemic syndrome (HUS and fatalities. Results We characterized the response to antibiotics of STEC O104:H4 isolates from two HUS patients during the German STEC outbreak in spring 2011 in comparison to the common STEC O157:H7. Liquid cultures of STEC O157:H7 and O104:H4 were incubated with graded dilutions of the antibiotics ciprofloxacin, meropenem, fosfomycin, gentamicin, rifampicin, and chloramphenicol. At defined times of antibiotic treatment, transcriptional activation of the STX2 gene, contents of STX and STX-activity in the culture supernatants were quantified. Unlike the common serotype O157:H7, STEC O104:H4 does not release STX in response to therapeutic concentrations of ciprofloxacin, meropenem, fosfomycin, and chloramphenicol. Conclusions In future outbreaks, the response of the respective epidemiologic STEC strain to antibiotics should be rapidly characterized in order to identify antibiotics that do not enhance the release of STX. This will eventually allow clinical studies tackling the question whether antibiotic treatment impacts on the eradication of STEC, clinical course of disease, and frequency of carriers.

  17. MOF and H4 K16 Acetylation Play Important Roles in DNA Damage Repair by Modulating Recruitment of DNA Damage Repair Protein Mdc1 ▿

    Science.gov (United States)

    Li, Xiangzhi; Corsa, Callie Ann Sprunger; Pan, Patricia W.; Wu, Lipeng; Ferguson, David; Yu, Xiaochun; Min, Jinrong; Dou, Yali

    2010-01-01

    MOF (MYST1) is the major enzyme to catalyze acetylation of histone H4 lysine 16 (K16) and is highly conserved through evolution. Using a conditional knockout mouse model and the derived mouse embryonic fibroblast cell lines, we showed that loss of Mof led to a global reduction of H4 K16 acetylation, severe G2/M cell cycle arrest, massive chromosome aberration, and defects in ionizing radiation-induced DNA damage repair. We further showed that although early DNA damage sensing and signaling by ATM were normal in Mof-null cells, the recruitment of repair mediator protein Mdc1 and its downstream signaling proteins 53bp1 and Brca1 to DNA damage foci was completely abolished. Mechanistic studies suggested that Mof-mediated H4 K16 acetylation and an intact acidic pocket on H2A.X were essential for the recruitment of Mdc1. Removal of Mof and its associated proteins phenocopied a charge-neutralizing mutant of H2A.X. Given the well-characterized H4-H2A trans interactions in regulating higher-order chromatin structure, our study revealed a novel chromatin-based mechanism that regulates the DNA damage repair process. PMID:20837706

  18. Belastingsproeven op ankerbouten in asfalt : trek- en afschuifproeven op drie typen ankerbouten voor afschermvoorzieningen op H4-niveau. In opdracht van het Directoraat-Generaal Rijkswaterstaat, Bouwdienst Rijkswaterstaat.

    NARCIS (Netherlands)

    Pol, W.H.M. van de

    2000-01-01

    Under contract to the Dutch Department of Public Works Civil Engineering Division, SWOV Institute for Road Safety Research carried out simulation studies on the development of H4-level safety barriers. These included steel and concrete designs for a wide STEP barrier. Anchoring of these construction

  19. A study of the ground states of CaC2H+2,CaC2D+2 and CaC2H+4

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The geometries, vibrational frequencies and bind energies are reported for the ground states of CaC2H+2, CaC2D+2 and CaC2H+4. CaC2H+2 and CaC2H+4 equilibrium geometries have C2v symmetry with the metal ion lying in the perpendicular bisector of the C-C bond. The ground state in both CaC2H+2 and CaC2H+4 molecules ia a 2A1 state and the binding in the ground state is mainly electrostatic. For both CaC2H+2 and CaC2H+4 the ligand is only slightly distorted from its free ligand structure, the C-C distance has hardly increased and there is only a very small bending of the H atom away from the Ca atom. This is consistent with the electrostatic nature of the bonding. Two different approaches-Hartree-Fock(HF) and density functional theory methods(DFT)-are used and basis sets here used is 6-311+G(3df,2p). The DFT results are in good agreement with experiments, namely, DFT methods provide the benefits that some more expensive ab initio methods can do, but at essentially HF cost. So it is important to include electron correlation for accurate results in this study.

  20. Catalytic function of the PR-Set7 histone H4 lysine 20 monomethyltransferase is essential for mitotic entry and genomic stability.

    Science.gov (United States)

    Houston, Sabrina I; McManus, Kirk J; Adams, Melissa M; Sims, Jennifer K; Carpenter, Phillip B; Hendzel, Michael J; Rice, Judd C

    2008-07-11

    Histone-modifying enzymes play a critical role in modulating chromatin dynamics. In this report we demonstrate that one of these enzymes, PR-Set7, and its corresponding histone modification, the monomethylation of histone H4 lysine 20 (H4K20), display a distinct cell cycle profile in mammalian cells: low at G1, increased during late S phase and G2, and maximal from prometaphase to anaphase. The lack of PR-Set7 and monomethylated H4K20 resulted in a number of aberrant phenotypes in several different mammalian cell types. These include the inability of cells to progress past G2, global chromosome condensation failure, aberrant centrosome amplification, and substantial DNA damage. By employing a catalytically dead dominant negative PR-Set7 mutant, we discovered that its mono-methyltransferase activity was required to prevent these phenotypes. Importantly, we demonstrate that all of the aberrant phenotypes associated with the loss of PR-Set7 enzymatic function occur independently of p53. Collectively, our findings demonstrate that PR-Set7 enzymatic activity is essential for mammalian cell cycle progression and for the maintenance of genomic stability, most likely by monomethylating histone H4K20. Our results predict that alterations of this pathway could result in gross chromosomal aberrations and aneuploidy.

  1. Synthesis of Acetic Acid on Pd-H4SiW12O40-Based Catalysts by Direct Oxidation of Ethylene

    Institute of Scientific and Technical Information of China (English)

    Xinping Wang; Kegong Fang; Jianlu Zhang; Tianxi Cai

    2002-01-01

    Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O4o-based catalystswas studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of thecatalysts with different compositions and configurations, it is proposed that acetic acid is predominantlyproduced via an intermediate of acetaldehyde. This can be easily confirmed by comparing the productdistributions in the integral and the differential reactors. The active sites for acetic acid formation areconsidered to exist mainly at the boundaries between the H4SiW12O4o and the Pd particles. The Pd-basedcatalysts reduced by H2/N2 have higher activities than those reduced by hydrazine, as explained by thedegree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption. It was foundthat the Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than thatwith potassium selenite, and that the acetic acid yield can be greatly increased by adding a suitable amountof dichloroethane (C2H4Cl2/C2H4 mole ratio=0.03) to the reactants.

  2. Full-Dimensional Potential Energy and Dipole Moment Surfaces of GeH4 Molecule and Accurate First-Principle Rotationally Resolved Intensity Predictions in the Infrared.

    Science.gov (United States)

    Nikitin, A V; Rey, M; Rodina, A; Krishna, B M; Tyuterev, Vl G

    2016-11-17

    Nine-dimensional potential energy surface (PES) and dipole moment surface (DMS) of the germane molecule are constructed using extended ab initio CCSD(T) calculations at 19 882 points. PES analytical representation is determined as an expansion in nonlinear symmetry adapted products of orthogonal and internal coordinates involving 340 parameters up to eighth order. Minor empirical refinement of the equilibrium geometry and of four quadratic parameters of the PES computed at the CCSD(T)/aug-cc-pVQZ-DK level of the theory yielded the accuracy below 1 cm(-1) for all experimentally known vibrational band centers of five stable isotopologues of (70)GeH4, (72)GeH4, (73)GeH4, (74)GeH4, and (76)GeH4 up to 8300 cm(-1). The optimized equilibrium bond re = 1.517 594 Å is very close to best ab initio values. Rotational energies up to J = 15 are calculated using potential expansion in normal coordinate tensors with maximum errors of 0.004 and 0.0006 cm(-1) for (74)GeH4 and (76)GeH4. The DMS analytical representation is determined through an expansion in symmetry-adapted products of internal nonlinear coordinates involving 967 parameters up to the sixth order. Vibration-rotation line intensities of five stable germane isotopologues were calculated from purely ab initio DMS using nuclear motion variational calculations with a full account of the tetrahedral symmetry of the molecules. For the first time a good overall agreement of main absorption features with experimental rotationally resolved Pacific Northwest National Laboratory spectra was achieved in the entire range of 700-5300 cm(-1). It was found that very accurate description of state-dependent isotopic shifts is mandatory to correctly describe complex patterns of observed spectra at natural isotopic abundance resulting from the superposition of five stable isotopologues. The data obtained in this work will be made available through the TheoReTS information system.

  3. Definitive evidence for the existence of isomeric chlorophenyl radicals (C6H4Cl) from charge inversion mass spectrometry and DFT calculations

    Science.gov (United States)

    Hayakawa, Shigeo; Matsubara, Hiroshi; Kawamura, Yoshiaki; Iwamoto, Kenichi

    2007-05-01

    Free radical species are much more reactive than stable molecules, and so usually exist only as transient intermediates in chemical reactions. Charge inversion mass spectrometry using alkali metal targets is an effective method for determining the structure and dissociation processes of radicals, and can also enable differentiation between isomeric forms of compounds whose parent ions have similar mass spectra and similar collisionally activated dissociation spectra, such as the isomers of dichlorobenzene and chlorophenol. The charge inversion process using alkali metal targets proceeds via near-resonant neutralization, followed by spontaneous dissociation of the excited neutrals, and then endothermic negative ion formation. In the normalized charge inversion spectra of ortho-, meta-, and para-dichlorobenzene (C6H4Cl2) measured in this work, the intensities of the peaks associated with chlorine anions (Cl-) are almost same for each of the isomers, whereas the intensities of the peaks associated with the chlorophenyl anions (C6H4Cl-) display a strong dependence on the isomeric structure of the parent compound. The similarities of the Cl- ion peak intensities indicate that neutralization cross-sections and branching ratios to produce Cl radicals are the same for each of the isomeric precursor C6H4Cl2+ ions. The strong isomer-dependence of the peak intensities of C6H4Cl- anions suggests that the chlorophenyl radicals (C6H4Cl) formed from C6H4Cl2 by loss of Cl do not undergo isomerization, and that the electron transfer cross-sections to form the negative ions are strongly isomer-dependent. Density functional theory (DFT) calculations on the o-, m-, and p-C6H4Cl radicals show that the barriers to isomerization are in excess of 2.8 eV, and these high isomerization barriers are believed to be the reason for the absence of isomerization among the C6H4Cl radicals during the charge inversion process. Calculated adiabatic electron affinities and vertical electron affinities

  4. Electronic and electrochemical properties of platinum(II) and platinum-mercury-carboxylato complexes containing 2-Me2NCH2C6H4, 2,6-(Me2NCH2)2C6H3- and 2-Me2NC6H4CH2 - ligands

    NARCIS (Netherlands)

    Koten, G. van; Ploeg, A.F.M.J. van der; Schmitz, J.E.J.; Linden, J.G.M. van der

    1982-01-01

    The organoplatinum(II) compounds [{2, 6-(Me{2}NCH{2}){2}C{6}H{3}}PtBr] and cis-[(C-N){2}Pt] (C-N = 2-Me{2}NCH{2}C{6}H{4}, 2-Me{2}NC{6}H{4}CH{2}) can be chemically irreversibly oxidized in the potential range 1.00 to 1.35 V vs. an Ag/AgCl electrode, whereas the organoplatinum@?mercury complexes [{2,6

  5. Comparative genomic analysis of two novel sporadic Shiga toxin-producing Escherichia coli O104:H4 strains isolated 2011 in Germany.

    Directory of Open Access Journals (Sweden)

    Erhard Tietze

    Full Text Available A large outbreak of gastrointestinal disease occurred in 2011 in Germany which resulted in almost 4000 patients with acute gastroenteritis or hemorrhagic colitis, 855 cases of a hemolytic uremic syndrome and 53 deaths. The pathogen was an uncommon, multiresistant Escherichia coli strain of serotype O104:H4 which expressed a Shiga toxin characteristic of enterohemorrhagic E. coli and in addition virulence factors common to enteroaggregative E. coli. During post-epidemic surveillance of Shiga toxin-producing E. coli (STEC all but two of O104:H4 isolates were indistinguishable from the epidemic strain. Here we describe two novel STEC O104:H4 strains isolated in close spatiotemporal proximity to the outbreak which show a virulence gene panel, a Shiga toxin-mediated cytotoxicity towards Vero cells and aggregative adherence to Hep-2 cells comparable to the outbreak strain. They differ however both from the epidemic strain and from each other, by their antibiotic resistance phenotypes and some other features as determined by routine epidemiological subtyping methods. Whole genome sequencing of these two strains, of ten outbreak strain isolates originating from different time points of the outbreak and of one historical sporadic EHEC O104:H4 isolate was performed. Sequence analysis revealed a clear phylogenetic distance between the two variant strains and the outbreak strain finally identifying them as epidemiologically unrelated isolates from sporadic cases. These findings add to the knowledge about this emerging pathogen, illustrating a certain diversity within the bacterial core genome as well as loss and gain of accessory elements. Our results do also support the view that distinct new variants of STEC O104:H4 repeatedly might originate from yet unknown reservoirs, rather than that there would be a continuous diversification of a single epidemic strain established and circulating in Germany after the large outbreak in 2011.

  6. A search for presynaptic inhibitory histamine receptors in guinea-pig tissues: Further H3 receptors but no evidence for H4 receptors.

    Science.gov (United States)

    Petri, Doris; Schlicker, Eberhard

    2016-07-01

    The histamine H4 receptor is coupled to Gi/o proteins and expressed on inflammatory cells and lymphoid tissues; it was suggested that this receptor also occurs in the brain or on peripheral neurones. Since many Gi/o protein-coupled receptors, including the H3 receptor, serve as presynaptic inhibitory receptors, we studied whether the sympathetic neurones supplying four peripheral tissues and the cholinergic neurones in the hippocampus from the guinea-pig are equipped with release-modulating H4 and H3 receptors. For this purpose, we preincubated tissue pieces from the aorta, atrium, renal cortex and vas deferens with (3)H-noradrenaline and hippocampal slices with (3)H-choline and determined the electrically evoked tritium overflow. The stimulation-evoked overflow in the five superfused tissues was inhibited by the muscarinic receptor agonist oxotremorine, which served as a positive control, but not affected by the H4 receptor agonist 4-methylhistamine. The H3 receptor agonist R-α-methylhistamine inhibited noradrenaline release in the peripheral tissues without affecting acetylcholine release in the hippocampal slices. Thioperamide shifted the concentration-response curve of histamine in the aorta and the renal cortex to the right, yielding apparent pA2 values of 8.0 and 8.1, respectively, which are close to its affinity at other H3 receptors but higher by one log unit than its pKi at the H4 receptor of the guinea-pig. In conclusion, histamine H4 receptors could not be identified in five experimental models of the guinea-pig that are suited for the detection of presynaptic inhibitory receptors whereas H3 receptors could be shown in the peripheral tissues but not in the hippocampus. This article is part of the Special Issue entitled 'Histamine Receptors'.

  7. Mechanical and Thermal Dehydrogenation of Lithium Alanate (LiAlH4 and Lithium Amide (LiNH2 Hydride Composites

    Directory of Open Access Journals (Sweden)

    Leszek Zbroniec

    2012-04-01

    Full Text Available Hydrogen storage properties of the (nLiAlH4 + LiNH2 hydride composite where n = 1, 3, 11.5 and 30, synthesized by high energy ball milling have been investigated. The composite with the molar ratio n = 1 releases large quantities of H2 (up to ~5 wt.% during ball milling up to 100–150 min. The quantity of released H2 rapidly decreases for the molar ratio n = 3 and is not observed for n = 11.5 and 30. The XRD studies indicate that the H2 release is a result of a solid state decomposition of LiAlH4 into (1/3Li3AlH6 + (2/3Al + H2 and subsequently decomposition of (1/3Li3AlH6 into LiH + (1/3Al + 0.5H2. Apparently, LiAlH4 is profoundly destabilized during ball milling by the presence of a large quantity of LiNH2 (37.7 wt.% in the n = 1 composite. The rate of dehydrogenation at 100–170 °C (at 1 bar H2 is adversely affected by insufficient microstructural refinement, as observed for the n = 1 composite, which was milled for only 2 min to avoid H2 discharge during milling. XRD studies show that isothermal dehydrogenation of (nLiAlH4 + LiNH2 occurs by the same LiAlH4 decomposition reactions as those found during ball milling. The ball milled n = 1 composite stored under Ar at 80 °C slowly discharges large quantities of H2 approaching 3.5 wt.% after 8 days of storage.

  8. Condensation patterns of prophase/prometaphase chromosome are correlated with H4K5 histone acetylation and genomic DNA contents in plants.

    Science.gov (United States)

    Feitoza, Lidiane; Costa, Lucas; Guerra, Marcelo

    2017-01-01

    Mitotic prophase chromosome condensation plays an essential role in nuclear division being therefore regulated by highly conserved mechanisms. However, degrees of chromatin condensation in prophase-prometaphase cells may vary along the chromosomes resulting in specific condensation patterns. We examined different condensation patterns (CPs) of prophase and prometaphase chromosomes and investigated their relationship with genome size and distribution of histone H4 acetylated at lysine 5 (H4K5ac) in 17 plant species. Our results showed that most species with small genomes (2C < 5 pg) (Arachis pusilla, Bixa orellana, Costus spiralis, Eleutherine bulbosa, Indigofera campestris, Phaseolus lunatus, P. vulgaris, Poncirus trifoliata, and Solanum lycopersicum) displayed prophase chromosomes with late condensing terminal regions that were highly enriched in H4K5ac, and early condensing regions with apparently non-acetylated proximal chromatin. The species with large genomes (Allium cepa, Callisia repens, Araucaria angustifolia and Nothoscordum pulchellum) displayed uniformly condensed and acetylated prophase/prometaphase chromosomes. Three species with small genomes (Eleocharis geniculata, Rhynchospora pubera, and R. tenuis) displayed CP and H4K5ac labeling patterns similar to species with large genomes, whereas a forth species (Emilia sonchifolia) exhibited a gradual chromosome labeling, being more acetylated in the terminal regions and less acetylated in the proximal ones. The nucleolus organizer chromatin was the only chromosomal region that in prometaphase or metaphase could be hyperacetylated, hypoacetylated or non-acetylated, depending on the species. Our data indicate that the CP of a plant chromosome complement is influenced but not exclusively determined by nuclear and chromosomal DNA contents, whereas the CP of individual chromosomes is clearly correlated with H4K5ac distribution.

  9. Interactive effects of temperature, pH, and water activity on the growth kinetics of Shiga toxin-producing Escherichia coli O104:H4 3.

    Science.gov (United States)

    Juneja, Vijay K; Mukhopadhyay, Sudarsan; Ukuku, Dike; Hwang, Cheng-An; Wu, Vivian C H; Thippareddi, Harshavardhan

    2014-05-01

    The risk of non-O157 Shiga toxin-producing Escherichia coli strains has become a growing public health concern. Several studies characterized the behavior of E. coli O157:H7; however, no reports on the influence of multiple factors on E. coli O104:H4 are available. This study examined the effects and interactions of temperature (7 to 46°C), pH (4.5 to 8.5), and water activity (aw ; 0.95 to 0.99) on the growth kinetics of E. coli O104:H4 and developed predictive models to estimate its growth potential in foods. Growth kinetics studies for each of the 23 variable combinations from a central composite design were performed. Growth data were used to obtain the lag phase duration (LPD), exponential growth rate, generation time, and maximum population density (MPD). These growth parameters as a function of temperature, pH, and aw as controlling factors were analyzed to generate second-order response surface models. The results indicate that the observed MPD was dependent on the pH, aw, and temperature of the growth medium. Increasing temperature resulted in a concomitant decrease in LPD. Regression analysis suggests that temperature, pH, and aw significantly affect the LPD, exponential growth rate, generation time, and MPD of E. coli O104:H4. A comparison between the observed values and those of E. coli O157:H7 predictions obtained by using the U. S. Department of Agriculture Pathogen Modeling Program indicated that E. coli O104:H4 grows faster than E. coli O157:H7. The developed models were validated with alfalfa and broccoli sprouts. These models will provide risk assessors and food safety managers a rapid means of estimating the likelihood that the pathogen, if present, would grow in response to the interaction of the three variables assessed.

  10. Comparative genomic analysis of two novel sporadic Shiga toxin-producing Escherichia coli O104:H4 strains isolated 2011 in Germany.

    Science.gov (United States)

    Tietze, Erhard; Dabrowski, Piotr Wojciech; Prager, Rita; Radonic, Aleksandar; Fruth, Angelika; Auraß, Philipp; Nitsche, Andreas; Mielke, Martin; Flieger, Antje

    2015-01-01

    A large outbreak of gastrointestinal disease occurred in 2011 in Germany which resulted in almost 4000 patients with acute gastroenteritis or hemorrhagic colitis, 855 cases of a hemolytic uremic syndrome and 53 deaths. The pathogen was an uncommon, multiresistant Escherichia coli strain of serotype O104:H4 which expressed a Shiga toxin characteristic of enterohemorrhagic E. coli and in addition virulence factors common to enteroaggregative E. coli. During post-epidemic surveillance of Shiga toxin-producing E. coli (STEC) all but two of O104:H4 isolates were indistinguishable from the epidemic strain. Here we describe two novel STEC O104:H4 strains isolated in close spatiotemporal proximity to the outbreak which show a virulence gene panel, a Shiga toxin-mediated cytotoxicity towards Vero cells and aggregative adherence to Hep-2 cells comparable to the outbreak strain. They differ however both from the epidemic strain and from each other, by their antibiotic resistance phenotypes and some other features as determined by routine epidemiological subtyping methods. Whole genome sequencing of these two strains, of ten outbreak strain isolates originating from different time points of the outbreak and of one historical sporadic EHEC O104:H4 isolate was performed. Sequence analysis revealed a clear phylogenetic distance between the two variant strains and the outbreak strain finally identifying them as epidemiologically unrelated isolates from sporadic cases. These findings add to the knowledge about this emerging pathogen, illustrating a certain diversity within the bacterial core genome as well as loss and gain of accessory elements. Our results do also support the view that distinct new variants of STEC O104:H4 repeatedly might originate from yet unknown reservoirs, rather than that there would be a continuous diversification of a single epidemic strain established and circulating in Germany after the large outbreak in 2011.

  11. First high resolution ro-vibrational study of the (0200), (0101) and (0002) vibrational states of MGeH4 (M=76,74)

    Science.gov (United States)

    Ulenikov, O. N.; Gromova, O. V.; Bekhtereva, E. S.; Raspopova, N. I.; Fomchenko, A. L.; Sennikov, P. G.; Koshelev, M. A.; Velmuzhova, I. A.; Velmuzhov, A. P.

    2016-10-01

    The infrared spectra of GeH4 (88.1% of 76GeH4, 11.5% of 74GeH4, and a minor amounts of three other stable isotopic species in the sample) were measured in the region of 1450 - 2000cm-1 with a Bruker IFS 125HR Fourier transform interferometer (Nizhny Novgorod, Russia) and analyzed. 2254 transitions with Jmax=19 were assigned for the first time to the bands 2ν4(F2), 2ν4(E), ν2 +ν4(F2), ν2 +ν4(F1), 2ν2(A1) and 2ν2(E) of the 76GeH4 isotopologue. Numerous "hot" Dyad-Pentad transitions also were recorded and assigned for the first time in the region of 700 - 1080cm-1 (in general, about 1000 transitions). Rotational, centrifugal distortion, tetrahedral splitting, and interaction parameters for the (0002 ,F2), (0002 , E), (0002 ,A1), (0101 ,F2), (0101 ,F1), (0200 ,A1) and (0200 , E) vibrational states were determined from the fit of experimental line positions. The obtained set of parameters reproduces the initial experimental data with accuracy close to experimental uncertainties. Results of the analogous analysis of the 74GeH4 isotopologue (the number of assigned transitions is 309 "cold" and 99 "hot" ones) are presented also. Obtained from the weighted fit set of spectroscopic parameters of the effective Hamiltonian reproduces the initial experimental data with the drms better than 3 ×10-4cm-1.

  12. Ternary LiBH4-MgH2-NaAlH4 hydride confined into nanoporous carbon host for reversible hydrogen storage

    Science.gov (United States)

    Plerdsranoy, Praphatsorn; Utke, Rapee

    2016-03-01

    Ternary hydride of LiBH4-MgH2-NaAlH4 confined into carbo n aerogel scaffold (CAS) via melt infiltration for reversible hydrogen storage is proposed. Nanoconfinement of hydrides into CAS is obtained together with surface occupation of some phases, such as Al and/or LiH. Regarding nanoconfinement, not only multiple-step decomposition of LiBH4-MgH2-NaAlH4 hydride reduces to about single step, but also reduction of dehydrogenation temperature is significantly observed, for example, ∆T up to 70 °C regarding last dehydrogenation step. Moreover, decomposition of NaBH4 in nanoconfined sample can be done at 360 °C (dehydrogenation temperature in this study), which is 115 and 180 °C lower than that of NaBH4 in milled LiBH4-MgH2-NaAlH4 and bulk NaBH4, respectively. The reaction of LiBH4+NaAlH4→LiAlH4+NaBH4 takes place during nanoconfinement and the decomposition of LiAlH4 is observed, resulting deficient hydrogen content liberated. However, hydrogen content released (1st cycle) and reproduced (2nd-4th cycles) from this ternary hydride enhances up to 11% and 22% of full hydrogen storage capacity due to nanoconfinement. After rehydrogenation (T=360 °C and P(H2)=50 bar H2 for 12 h), NaBH4, MgH2, and Li3AlH6 are reversible, whereas Li3AlH6 and NaBH4 in milled sample cannot be recovered due to deficient hydrogen pressure (T=360 °C and P(H2)=80 bar) and probably evaporation of molten sodium during dehydrogenation, respectively. The latter results in inferior hydrogen content reproduced from milled sample to nanoconfined sample.

  13. Interactions with ATP, DNA Cleavage and Anti-tumor Activities of Complexes with Anions [Mo(V)O2(O2CeH4)2]3-, [Mo(Ⅴ)0.5W(Ⅵ)0.5O2(O2C6H4)2]2.5- and [W(Ⅵ)O2(O2C6H4)2]2-

    Institute of Scientific and Technical Information of China (English)

    鲁晓明; 姜凌; 毛希安; 叶朝晖; 卢景芬; 崔景荣

    2005-01-01

    (NH3CH2CH2NH2)3[Mo(Ⅴ)O2(O2C6H4)2] (1), (NH3CH2CH2NH2)2.5[Mo(Ⅴ)o.sW(Ⅵ)o.502(O2C6H4)2] (2) and(NH3CH2CH2NH2)2[VC(Ⅵ)O2(O2C6H4)2] (3) were synthesized, structurally characterized by X-ray diffraction analysis, and studied on their interactions with ATP, their DNA cleavage activities and antitumor properties. The redox state of molybdenum was not changed on going from crystal to aqueous solutions in complexes 1 and 2, while tungsten underwent reduction from W(VI) to W(V) in complexes 2 and 3. ATP promoted the oxidation of both molybdenum and tungsten from M(Ⅴ) to M(Ⅵ) and the hydrolysis of catecholate ligands in solution consisting of ATP and the complexes. Complex 1 possesses fairly good activity to DNA cleavage and against tumor S180 in mice, and is more effective than the control drug cyclophosphamide under the identical conditions. However, complexes 2 and 3 exhibited marginal effectiveness. The effectiveness of anti-tumor of the complexes was related positively to their DNA cleavage activities and their hydrolysis of catecholate ligands.

  14. A comparative adsorption study of C2H4 and SO2 on clinoptilolite-rich tuff: effect of acid treatment.

    Science.gov (United States)

    Erdoğan Alver, Burcu

    2013-11-15

    In this study, ethylene (C2H4) and sulphur dioxide (SO2) adsorption properties of clinoptilolite tuff from Gördes, Turkey and that of acid treated forms were studied at 293K using volumetric apparatus up to 38 and 100 kPa, respectively. In order to consider the effect of acid treatment on structural and gas adsorption properties of zeolite, clinoptilolite mineral was modified with 0.1, 0.5, 1.0 and 2.0M HCl solutions at 70 °C during 3h. XRD, XRF, TG/DTG, DTA and N2 adsorption methods were employed for thermal and structural characterization of clinoptilolite samples before and after the acid treatment. SO2 adsorption capacities (2.356-2.739 mmol/g) of the clinoptilolite samples were superior to those of the C2H4 adsorptions (0.619-1.219 mmol/g).

  15. Preparation and Separation of Monosilane and Disilane%SiH4,Si2H6的制备与分离

    Institute of Scientific and Technical Information of China (English)

    余京松; 田波

    2001-01-01

    用Mg2Si制备SiH4必然伴随产生Si2H6.经二级低温冷凝 ,分子筛吸附和恒温恒压汽化等工艺技术过程,能够对两种气体进行最有效的分离 .并且可以制备Si2H6和总杂质含量≤10×10-6,基磷<0.2×10-9, 基硼<0.05×10-9的高纯SiH4.

  16. Synthesis and crystal structure of 4-fluorobenzylammonium dihydrogen phosphate, [FC6H4CH2NH3]H2PO4

    Directory of Open Access Journals (Sweden)

    Ali Rayes

    2016-12-01

    Full Text Available The asymmetric unit of the title salt, [p-FC6H4CH2NH3]+·H2PO4−, contains one 4-fluorobenzylammonium cation and one dihydrogen phosphate anion. In the crystal, the H2PO4− anions are linked by O—H...O hydrogen bonds to build corrugated layers extending parallel to the ab plane. The FC6H4CH2NH3+ cations lie between these anionic layers to maximize the electrostatic interactions and are linked to the H2PO4− anions through N—H...O hydrogen bonds, forming a three-dimensional supramolecular network. Two hydrogen atoms belonging to the dihydrogen phosphate anion are statistically occupied due to disorder along the OH...HO direction.

  17. Evaluating the performance of graphene with structural defect and functionalized by –C6H4 as an electrode active material for supercapacitors

    Directory of Open Access Journals (Sweden)

    S M Mousavi-Khoshdel

    2017-02-01

    Full Text Available In this study, quantum capacitance of graphene-based electrodes is evaluated using Density Functional Theory (DFT calculations. The obtained results showed that quantum capacitance of graphene-based supercapacitors could be significantly improved by existence of structural defects on the graphene sheets at sufficiently high concentrations because of creating impure states resulted from carbon pz orbitals involved in defect. In another section of calculations, quantum capacitance of functionalized graphene with –C6H4, is evaluated. The obtained results of calculations showed that functionalized graphene with this functional group have a very good capacitance in comparison with pristine graphene, especially at smaller voltages of less than -1.0 V or greater than 1.0 V. Hybrid configurations between structural defects and functional group of –C6H4 was also studied. In general, the results indicated that the combined configuration shows higher capacity than pristine graphene

  18. Neutron scattering studies of the H2a-H2b and (H3-H4)/sub 2/ histone complexes

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, R.D.

    1982-01-01

    Neutron scattering experiments have shown that both the (H3-H4)/sub 2/ and H2a-H2b histone complexes are quite asymmetric in solution. The (H3-H4)/sub 2/ tetramer is an oblate or flattened structure, with a radius of gyration almost as large as that of the core octamer. If the tetramer is primarily globular, it must have an axial ratio of about 1:5. It is more likely, however, that this asymmetry results in part from N-terminal arms that extend outward approximately within the major plane of the particle. If this is the case, less asymmetric models for the globular part of the tetramer, including a dislocated disk, can be made consistent with the scattering data. The H2a-H2b dimer, on the other hand, is an elongated structure. 48 references, 12 figures, 1 table.

  19. Solvothermal Synthesis and Crystal Structure of a Novel Inorganic—Organic Hybrid Material,Fe2O(OH)(C5H4NCOO)SO4

    Institute of Scientific and Technical Information of China (English)

    郭洪猷; 李增和; 李秀艳; 张长远; 王如骥

    2003-01-01

    A novel inorganic-organic hybrid material,Fe2O(OH)(C5H4-NCOO)SO4 was synthesized via solvothermal route using a reaction of FeCl3·6H2O,KCNS,and 4-cyanopyridine in aqueous solution of H2O2 and ethanol at 130℃ for 3d.The compound crystallized in monoclinic space group P21,with cell parameters a=0.73850(15)nm,b=0.65100(13)nm,c=1.0546(2)nm,β=90.36(3)°,V=0.50700(18)nm3 and Z=2.The structure is constructed with inorganic layered [Fe2O(OH)SO4)+ cations linked by organic (C5H4NCOO)- anions.The compound is thermally stable up to approximately 240℃.

  20. Silane photoabsorption spectra mear the Si 2p thresholds:the geometry of Si 2p excited SiH4

    Institute of Scientific and Technical Information of China (English)

    张卫华; 李家明; 等

    2003-01-01

    Based on the multiple-scattering self-consistent-field method,we have studied the photoabsorption spectra near the Si 2p thresholds of silane,According to our calculations,the clear assignments of the inner-shell photoabsorption spectra are provided.In comparison with the high-resolution experimental spectra,the geometric structure of the Si 2p-excited SiH4 is recommended to be of a C2v symmetry.More specifically,the Si 2p-excited SiH4** have two bond lengths of 2.50 a.u. and another two bond lengths of 2.77 a.u.,and the corresponding two bond angles are 104.0° and 112.5° respectively.

  1. Photoabsorption and photoionization cross sections of NH3, PH3, H2S, C2H2, and C2H4 in the VUV region

    Science.gov (United States)

    Xia, T. J.; Chien, T. S.; Wu, C. Y. Robert; Judge, D. L.

    1991-01-01

    Using synchrotron radiation as a continuum light source, the photoabsorption and photoionization cross sections of NH3, PH3, H2S, C2H2, and C2H4 have been measured from their respective ionization thresholds to 1060 A. The vibrational constants associated with the nu(2) totally symmetric, out-of-plane bending vibration of the ground electronic state of PH3(+) have been obtained. The cross sections and quantum yields for producing neutral products through photoexcitation of these molecules in the given spectral regions have also been determined. In the present work, autoionization processes were found to be less important than dissociation and predissociation processes in NH3, PH3, and C2H4. Several experimental techniques have been employed in order to examine the various possible systematic errors critically.

  2. Histamine H3 and H4 receptor ligands modify vascular histamine levels in normal and arthritic large blood vessels in vivo.

    Science.gov (United States)

    Kyriakidis, Konstantinos; Zampeli, Evangelia; Palaiologou, Marina; Tiniakos, Dina; Tiligada, Ekaterini

    2015-01-01

    Growing evidence associates histamine with arthritis, but its implication in shaping vascular function in chronic inflammation remains largely elusive. This study explored the involvement of vascular histamine in the extra-articular responses in peripheral large blood vessels using a rat model of adjuvant-induced arthritis. Histamine levels were increased in the abdominal aorta and the inferior vena cava of arthritic animals. Contrary to the H1 receptor antagonist dimetindene, histamine induction was observed following administration of the H3 and H4 receptor ligands GSK334429 and JNJ7777120, respectively. In arthritis, prophylactic treatment with GSK334429 partially attenuated the clinical signs and restored basal histamine levels only in the abdominal aorta. This study is the first to implicate the H3 and H4 receptors in a concerted constitutive regulation of basal vascular histamine in the rat large blood vessels and to identify the H3 receptor as a component that may influence arterial histamine during the onset of arthritis.

  3. Um estudo teórico relativo à não-linearidade da ligação de hidrogênio em sistemas heterocíclicos C2H4O-C2H2 e C2H4S-C2H2 A theoretical study about the non-linearity of the hydrogen bonding in the C2H4O-C2H2 and C2H4S-C2H2 heterocyclic systems

    Directory of Open Access Journals (Sweden)

    Boaz G. Oliveira

    2007-10-01

    Full Text Available B3LYP/6-31G(d,p calculations were used to determine the optimized geometries of the C2H4O-C2H2 and C2H4S-C2H2 heterocyclic hydrogen-bonded complexes. Results of structural, rotational, electronic and vibrational parameters indicate that the hydrogen bonding is non-linear due to the pi bond of the acetylene interacting with the hydrogen atoms of the methyl groups of the three-membered rings. Moreover, the theoretical investigation showed that the non-linearity is much more intriguing, since there is a structural disjunction on the acetylene within the heterocyclic system.

  4. Mononuclear [NiII(L)(P-(o-C6H4S)2(o-C6H4SH))]0/1- (L = thiolate, selenolate, PPh3, and Cl) complexes with intramolecular [Ni...S...H...S]/[Ni...H...S] interactions modulated by the coordinated ligand L: relevance to the [NiFe] hydrogenases.

    Science.gov (United States)

    Chen, Chien-Hong; Lee, Gene-Hsiang; Liaw, Wen-Feng

    2006-03-06

    The shift of the IR nu(S)(-)(H) frequency to lower wavenumbers for the series of complexes [Ni(II)(L)(P-(o-C6H4S)2(o-C6H4SH))]0/1- (L = PPh3 (1), Cl (6), Se-p-C6H4-Cl (5), S-C4H3S (7), SePh (4)) indicates that a trend of increasing electronic donation of the L ligands coordinated to the Ni(II) center promotes intramolecular [Ni-S...H-S] interactions. Compared to the Ni...S(H) distance, in the range of 3.609-3.802 A in complexes 1 and 4-7, the Ni...S(CH3) distances of 2.540 and 2.914 A observed in the [Ni(II)(PPh3)(P(o-C6H4S)2(o-C6H4-SCH3))] complexes (8a and 8b, two conformational isomers with the chemical shift of the thioether methyl group at delta 1.820 (-60 degrees C) and 2.109 ppm (60 degrees C) (C4D8O)) and the Ni...S(CH3) distances of 3.258 and 3.229 A found in the [Ni(II)(L)(P(o-C6H4S)2(o-C6H4-SCH3))]1- complexes (L = SPh (9), SePh (10)) also support the idea that the pendant thiol protons of the Ni(II)-thiol complexes 1/4-7 were attracted by both the sulfur of thiolate and the nickel. The increased basicity (electronic density) of the nickel center regulated by the monodentate ligand attracted the proton of the pendant thiol effectively and caused the weaker S...H bond. In addition, the pendant thiol interaction modes in the solid state (complexes 1a and 1b, Scheme 1) may be controlled by the solvent of crystallization. Compared to complex 1a, the stronger intramolecular [Ni-S...H-S] interaction (or a combination of [Ni-S...H-S]/[Ni...H-S] interactions) found in complexes 4-7 led to the weaker S-H bond strength and accelerated the oxidation (by O2) of complexes 4-7 to produce the [Ni(Y)(L)(P(o-C6H4S)3)]1- (L = Se-p-C6H4-Cl (11), SePh (12), S-C4H3S (13)) complexes.

  5. Dehydrogenation kinetics, reversibility, and reaction mechanisms of reversible hydrogen storage material based on nanoconfined MgH2-NaAlH4

    Science.gov (United States)

    Plerdsranoy, Praphatsorn; Meethom, Sukanya; Utke, Rapee

    2015-12-01

    Studies of dehydrogenation kinetics, reversibility, and reaction mechanisms during de/rehydrogenation of nanoconfined MgH2-NaAlH4 into carbon aerogel scaffold (CAS) for reversible hydrogen storage material are for the first time proposed. Two different MgH2:NaAlH4 molar ratios (1:1 and 2:1) of hydride composite are melt infiltrated into CAS under 1:1 (CAS:hydride composite) weight ratio. Successful nanoconfinement is confirmed by N2 adsorption-desorption. Multiple-step dehydrogenation of milled samples is reduced to two-step reaction due to nanoconfinement. Peak temperatures corresponding to main dehydrogenation of nanoconfined samples significantly reduce as compared with those of milled samples, i.e., ∆T=up to 50 and 34 °C for nanoconfined sample with 1:1 and 2:1 (MgH2:NaAlH4) molar ratios, respectively. Hydrogen content released (the 1st cycle) and reproduced (the 2nd, 3rd, and 4th cycles) of nanoconfined samples enhance up to 80% and 68% with respect to theoretical hydrogen storage capacity, respectively, while those of milled samples are 71% and 38%, respectively. Remarkable hydrogen content reproduced after nanoconfinement is due to the fact that metallic Al obtained after dehydrogenation (T=300 °C under vacuum) of nanoconfined samples prefer to react with MgH2 and produces Al12Mg17, favorable for reversibility of MgH2-NaAlH4 system, whereas that of milled samples stays in the form of unreacted Al under the same temperature and pressure condition.

  6. Involvement of the histamine H4 receptor in clozapine-induced hematopoietic toxicity: Vulnerability under granulocytic differentiation of HL-60 cells.

    Science.gov (United States)

    Goto, Aya; Mouri, Akihiro; Nagai, Tomoko; Yoshimi, Akira; Ukigai, Mako; Tsubai, Tomomi; Hida, Hirotake; Ozaki, Norio; Noda, Yukihiro

    2016-09-01

    Clozapine is an effective antipsychotic for treatment-resistant schizophrenia, but can cause fatal hematopoietic toxicity as agranulocytosis. To elucidate the mechanism of hematopoietic toxicity induced by clozapine, we developed an in vitro assay system using HL-60 cells, and investigated the effect on hematopoiesis. HL-60 cells were differentiated by all-trans retinoic acid (ATRA) into three states according to the following hematopoietic process: undifferentiated HL-60 cells, those undergoing granulocytic ATRA-differentiation, and ATRA-differentiated granulocytic cells. Hematopoietic toxicity was evaluated by analyzing cell survival, cell proliferation, granulocytic differentiation, apoptosis, and necrosis. In undifferentiated HL-60 cells and ATRA-differentiated granulocytic cells, both clozapine (50 and 100μM) and doxorubicin (0.2µM) decreased the cell survival rate, but olanzapine (1-100µM) did not. Under granulocytic differentiation for 5days, clozapine, even at a concentration of 25μM, decreased survival without affecting granulocytic differentiation, increased caspase activity, and caused apoptosis rather than necrosis. Histamine H4 receptor mRNA was expressed in HL-60 cells, whereas the expression decreased under granulocytic ATRA-differentiation little by little. Both thioperamide, a histamine H4 receptor antagonist, and DEVD-FMK, a caspase-3 inhibitor, exerted protection against clozapine-induced survival rate reduction, but not of live cell counts. 4-Methylhistamine, a histamine H4 receptor agonist, decreased the survival rate and live cell counts, as did clozapine. HL-60 cells under granulocytic differentiation are vulnerable under in vitro assay conditions to hematopoietic toxicity induced by clozapine. Histamine H4 receptor is involved in the development of clozapine-induced hematopoietic toxicity through apoptosis, and may be a potential target for preventing its occurrence through granulocytic differentiation.

  7. The TIP60 complex regulates bivalent chromatin recognition by 53BP1 through direct H4K20me binding and H2AK15 acetylation

    Science.gov (United States)

    Jacquet, Karine; Fradet-Turcotte, Amélie; Avvakumov, Nikita; Lambert, Jean-Philippe; Roques, Céline; Pandita, Raj K.; Paquet, Eric; Herst, Pauline; Gingras, Anne-Claude; Pandita, Tej K.; Legube, Gaëlle; Doyon, Yannick; Durocher, Daniel; Côté, Jacques

    2016-01-01

    SUMMARY The NuA4/TIP60 acetyltransferase complex is a key regulator of genome expression and stability. Here, we identified MBTD1 as a new stable subunit of the complex and gleaned intriguing insights into TIP60’s function. Harboring a histone reader domain for H4K20me1/2, MBTD1 allows TIP60 to associate with specific gene promoters and to promote the repair of DNA double strand breaks by homologous recombination. Interestingly, the non-homologous end joining factor 53BP1 engages chromatin through simultaneous binding of H4K20me2 and H2AK15ub, and it was postulated that Tip60-dependent acetylation of H4 regulates this binding. Our findings now indicate that the TIP60 complex is a potent regulator of DNA damage repair pathways in part by targeting the same histone mark as 53BP1. In addition, deposition of H2AK15ub by RNF168 inhibits chromatin acetylation by TIP60, while this residue can be acetylated by TIP60 in vivo, blocking its ubiquitylation. Altogether, these results uncover an intricate mechanism orchestrated by the TIP60 complex which regulates 53BP1-dependent repair pathway selection through incompatible bivalent binding and modification of chromatin. PMID:27153538

  8. Detection of histone acetylation levels in the dorsal hippocampus reveals early tagging on specific residues of H2B and H4 histones in response to learning.

    Science.gov (United States)

    Bousiges, Olivier; Neidl, Romain; Majchrzak, Monique; Muller, Marc-Antoine; Barbelivien, Alexandra; Pereira de Vasconcelos, Anne; Schneider, Anne; Loeffler, Jean-Philippe; Cassel, Jean-Christophe; Boutillier, Anne-Laurence

    2013-01-01

    The recent literature provides evidence that epigenetic mechanisms such as DNA methylation and histone modification are crucial to gene transcription linked to synaptic plasticity in the mammalian brain--notably in the hippocampus--and memory formation. We measured global histone acetylation levels in the rat hippocampus at an early stage of spatial or fear memory formation. We found that H3, H4 and H2B underwent differential acetylation at specific sites depending on whether rats had been exposed to the context of a task without having to learn or had to learn about a place or fear therein: H3K9K14 acetylation was mostly responsive to any experimental conditions compared to naive animals, whereas H2B N-terminus and H4K12 acetylations were mostly associated with memory for either spatial or fear learning. Altogether, these data suggest that behavior/experience-dependent changes differently regulate specific acetylation modifications of histones in the hippocampus, depending on whether a memory trace is established or not: tagging of H3K9K14 could be associated with perception/processing of testing-related manipulations and context, thereby enhancing chromatin accessibility, while tagging of H2B N-terminus tail and H4K12 could be more closely associated with the formation of memories requiring an engagement of the hippocampus.

  9. Low-temperature reduction of Ge oxide by Si and SiH4 in low-pressure H2 and Ar environment

    Science.gov (United States)

    Minami, Kaichiro; Moriya, Atsushi; Yuasa, Kazuhiro; Maeda, Kiyohiko; Yamada, Masayuki; Kunii, Yasuo; Niwano, Michio; Murota, Junichi

    2015-08-01

    Introduction of Ge into ULSIs has become increasingly attractive because of the higher carrier mobility of Ge. Since Ge native oxide is formed easily in cleanroom air, the control of formation and reduction of the Ge oxide is requested for the introduction of Ge layers into Si process. Here, the reactions between gas phase Ge oxide and Si substrate and between the Ge oxide on Ge epitaxial layer and SiH4 are investigated. The native-oxidized Ge amount is obtained by calculating from chemically shifted peak intensity of Ge 3d measured by X-ray photoelectron spectroscopy. By the adsorption of the Ge oxide on Si(1 0 0) surface, pure Ge and Si oxide are formed on the Si surface even at 350 °C and the formed Ge amount tends to correspond to the oxidized Si amount, independently of the heat-treatment environment of H2 and Ar under the condition that Si oxide is not reduced by H2. By SiH4 treatment, the amount of the oxidized Ge on the Ge layer decreases drastically even at 350 °C and Si oxide is formed on the Ge layer. From these results, it is suggested that the Ge oxide is reduced even at 350 °C by Si or SiH4, and the Si oxide and the pure Ge are formed.

  10. F-/OH- substitution in [H4tren]4+ and [H3tren]3+ hydroxyfluorotitanates(IV) and classification of tren cation configurations

    Science.gov (United States)

    Lhoste, Jérôme; Body, Monique; Legein, Christophe; Ribaud, Annie; Leblanc, Marc; Maisonneuve, Vincent

    2014-09-01

    Three [H3tren]3+ or [H4tren]4+ hydroxyfluorotitanates(IV) are solvothermally synthesized from TiO2, tren amine, 40% HF aqueous solution and ethanol under microwave heating at 120 °C and 190 °C. [H4tren]·(TiF4.6(OH)1.4)2·2.7H2O (I) and β-[H3tren]·(TiF4.5(OH)1.5)·(F) (II) are described for the first time. The third compound, α-[H3tren]·(TiF4.7(OH)1.3)·(F) (III), was previously reported as a pure fluorotitanate. The structure determinations are performed from single crystal (I) and powder (II) X-ray diffraction data. The F-/OH- substitution, expected from the presence of water in the reaction medium, is characterized by chemical analyses and 19F MAS solid state NMR experiments: all three structures are built up from Ti(F,OH)62- octahedra and “free” fluoride ions or water molecules. “Free” fluoride ions are not affected by F-/OH- substitution. The electroneutrality is ensured by triprotonated or tetraprotonated tren amines which adopt specific configurations. Additionally, based on the analysis of [H3tren]3+ or [H4tren]4+ hydroxo/oxo/fluorometalates, a classification of the configurations of tren cations is proposed.

  11. A new organic-inorganic coordination complex material (C2H5-C6H4-NH2)2ZnBr2: Growth and structural properties

    Science.gov (United States)

    Harmouzi, Asmaa; Daro, Nathalie; Guionneau, Philippe; Belaaraj, Abdesselam; Khechoubi, El Mostafa

    2017-08-01

    Single crystals of an organic-inorganic hybrid (C2H5-C6H4-NH2)2ZnBr2 have been grown by the slow-diffusion method and characterized by Single-Crystal X-Ray Diffraction (SC-XRD) at 295 K. This compound crystallizes in the monoclinic system, with the space group C2/c and the following cell parameters: a = 32.336 (3) Å, b = 4.8539 (4) Å, c = 12.2334 (9) Å, β = 97.019 (5)°, V = 1905.7(3) Å3 and Z‧ = 4. The crystal packing is based on well-ordered alternating ZnBr2 inorganic layers and C2H5-C6H4-NH2 organic layers. The crystal structure has been analyzed and discussed in terms of molecular geometry as well as intra and intermolecular interactions. Comparisons with some homologues materials of general formula (R-NH2)2ZnX2 (X = Cl, Br), (R = C2H5-C6H4, C6H5) are also done.

  12. Carrier effects of dosing the H4IIE cells with 3,3',4,4'-tetrachlorobiphenyl (PCB77) in dimethyl sulfoxide or isooctane.

    Science.gov (United States)

    Yu, K O; Fisher, J W; Burton, G A; Tillitt, D E

    1997-08-01

    A rat hepatoma cell line, H4IIE, serves as a bioassay tool to assess the potential toxicity of dioxin-like chemicals, including polychlorinated biphenyls (PCB) in environmental samples. PCB exposure to these cells induces cytochrome (CYP) P4501A1 activity in a dose-dependent fashion, thus allowing assessment of mixtures. The objective of this study was to determine the effect of different carriers, dimethyl sulfoxide (DMSO) and isooctane on the concentrations of PCBs in the H4IIE cells and induction of CYP1A1 activity as measured by ethoxyresorufin O-deethylase (EROD) activity. H4IIE cells were dosed with three micrograms of UL-14C-PCB77/plate dissolved in DMSO or isooctane, and were harvested at sequential time periods for 4 days. PCB77 concentration and EROD activity were measured in the cells. EROD activity was greater when using DMSO as compared to isooctane, while there was no difference in the distribution of PCB77-derived radioactivities within the cell culture system based upon the carrier solvent used to deliver PCB77.

  13. The low temperature epitaxy of Ge on Si (1 0 0) substrate using two different precursors of GeH4 and Ge2H6

    Science.gov (United States)

    Kil, Yeon-Ho; Yuk, Sim-Hoon; Kim, Joung Hee; Kim, Taek Sung; Kim, Yong Tae; Choi, Chel-Jong; Shim, Kyu-Hwan

    2016-10-01

    We have investigated the initial stage of low temperature epitaxy (LTE) of Ge on 8″-dia. Si (1 0 0) substrate using a rapid thermal chemical vapor deposition (RTCVD) with two different precursors of GeH4 and Ge2H6. The quality of LTE Ge films such as surface morphology, defects and crystallinity were analyzed using SEM, AFM and TEM. Experimental results confirmed that the LTE Ge using Ge2H6 precursor was much more beneficial than the LTE using GeH4 in terms of growth rate (×10), stress relaxation (85% at surface), and crystal quality (low TDDs). The discrepancy looks originated from the weak Gesbnd Ge bonds requiring their dissociation energy small compared to the Gesbnd H bonds in GeH4 precursors, and the abundant supply of GeH3 molecules should stimulate chemical reactions at free surface sites. Our LTE technology would be promising for very thin Ge virtual substrate as well as be beneficial for nano-micro electronic devices in need of low temperature processes below 300-500 °C.

  14. Detection of histone acetylation levels in the dorsal hippocampus reveals early tagging on specific residues of H2B and H4 histones in response to learning.

    Directory of Open Access Journals (Sweden)

    Olivier Bousiges

    Full Text Available The recent literature provides evidence that epigenetic mechanisms such as DNA methylation and histone modification are crucial to gene transcription linked to synaptic plasticity in the mammalian brain--notably in the hippocampus--and memory formation. We measured global histone acetylation levels in the rat hippocampus at an early stage of spatial or fear memory formation. We found that H3, H4 and H2B underwent differential acetylation at specific sites depending on whether rats had been exposed to the context of a task without having to learn or had to learn about a place or fear therein: H3K9K14 acetylation was mostly responsive to any experimental conditions compared to naive animals, whereas H2B N-terminus and H4K12 acetylations were mostly associated with memory for either spatial or fear learning. Altogether, these data suggest that behavior/experience-dependent changes differently regulate specific acetylation modifications of histones in the hippocampus, depending on whether a memory trace is established or not: tagging of H3K9K14 could be associated with perception/processing of testing-related manipulations and context, thereby enhancing chromatin accessibility, while tagging of H2B N-terminus tail and H4K12 could be more closely associated with the formation of memories requiring an engagement of the hippocampus.

  15. Synthesis of Acetic Acid on Pd—H4SiW12O40—Based Catalysts by Direct Oxidation of Ethylene

    Institute of Scientific and Technical Information of China (English)

    XinpingWang; KegongFang; 等

    2002-01-01

    Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor,From the performance of the catalysts with different compositions and configurations,it is proposed that acetic acid is predominantly produced via an intermediate of acetaldehyde ,This can be easily confirmed by comparing the product distributions in the integral and the differential reactors,The active sites for acetic acid formation are considered to exist mainly at the boundaries between the H2SiW12O40 and the Pd particles,The Pd-based catalysts reduced by H2/N2 have higher activities than those reduced by hydrazine,as explained by the degree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption It was found that the Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than that with potassium selenite ,and that the acetic acid yield can be greatly increased by adding a suitable amount of dichloroethane (C2H4Cl2/C2H4 mole ratio=0.03) to the reactants.

  16. Dry sol-gel condensation of p-X-C6H4SiH3 (X = H, CH3, CH3O, F, Cl) to organosilica p-X-C6H4SiO3 using nickelocene.

    Science.gov (United States)

    Cho, Myong-Shik; Kim, Bo-Hye; Hwang, Yun-Mi; Woo, Hee-Gweon; Kim, Do-Heyoung

    2006-11-01

    The dry sol-gel reaction at toluene in ambient air atmosphere of p-X-C6H4SiH3 (X = H, CH3, CH3O, F, Cl) to p-C6H4SiO3 in high yield, catalyzed by nickelocene, is reported. The highest yield, molecular weight, polydispersity index, and TGA residue yield were obtained for p-Cl-C6H4SiH3. Some degree of unreacted Si-H bonds still remained in the gel because of steric reason. All the insoluble gels adopt an amorphous structure with a smooth surface. A plausible mechanism for the dry sol-gel reaction was suggested.

  17. 氢化燃烧合成Mg2NiH4及氢化物放氢温度的研究%Studies on Mg2 NiH4 synthesis by hydriding combustion and dehydriding temperature of hydride

    Institute of Scientific and Technical Information of China (English)

    徐光亮; 刘文斌; 肖定全

    2006-01-01

    报道了原料中不同镍含量对氢化燃烧合成Mg2NiH4的影响和生成物中各氢化物的放氢温度等相关研究.氢化燃烧合成的结果表明:当镍含量<54.6%时,随着镍含量增加,氢化燃烧合成物中的Mg2NiH4增加,MgH2减少;DSC-TG曲线的结果表明,Mg2NiH4、Mg2NiH0.3和MgH2分别在650、683、719K附近产生放氢吸热和失重.

  18. On isoelectronic fluorides [H 3tren]ṡ(AlF 6)ṡH 2O, [H 3tren]ṡ(AlF 6)ṡHF, [H 4tren]ṡ(AlF 6)ṡ(F) and the iron analogue [H 4tren]ṡ(FeF 6)ṡ(F)

    Science.gov (United States)

    Adil, K.; Ben Ali, A.; Leblanc, M.; Maisonneuve, V.

    2006-06-01

    [H 3tren]ṡ(AlF 6)ṡH 2O, [H 3tren]ṡ(AlF 6)ṡHF and [H 4tren]ṡ( MF 6)ṡ(F) ( M=Al, Fe), are obtained by hydrothermal technique and microwave heating in the (Al(OH) 3,FeF 3)- tren-(HF/H 2O)-ethanol system. Structure determinations are performed from single crystal X-ray diffraction data. All phases are built up from ( MF 6) 3- anions linked by hydrogen bonds to [H 3tren] 3+ or [H 4tren] 4+ cations and to water or HF molecules or "isolated" fluoride anions. [H 3tren] 3+ and [H 4tren] 4+ cations adopt a "spider" shape configuration. Surprisingly, the HF molecule is strongly hydrogen bonded with one fluoride ion of the AlF 6 octahedron (d=2.38 Å) in [H 3tren]ṡ(AlF 6)ṡHF while "isolated" fluoride ion is weakly coordinated by three hydrogen atoms in [H 4tren]ṡ( MF 6)ṡ(F). The evolution of the formulations, from [H 3tren]ṡ(AlF 6)ṡH 2O to [H 3tren]ṡ(AlF 6)ṡHF and to [H 4tren]ṡ( MF 6)ṡ(F) ( M=Al, Fe), is linked with the increase of the HF content of the starting solution. The volumes per formula unit decrease from 321.3(1) Å 3 and 320.6(1) Å 3 in [H 3tren]ṡ(AlF 6)ṡH 2O and [H 3tren]ṡ(AlF 6)ṡHF, respectively, to 298.5(4) Å 3 in [H 4tren]ṡ(AlF 6)ṡ(F).

  19. NR1H4 analysis in patients with progressive familial intrahepatic cholestasis, drug-induced cholestasis or intrahepatic cholestasis of pregnancy unrelated to ATP8B1, ABCB11 and ABCB4 mutations.

    Science.gov (United States)

    Davit-Spraul, Anne; Gonzales, Emmanuel; Jacquemin, Emmanuel

    2012-12-01

    Farnesoid X receptor (FXR, NR1H4) controls bile acid homeostasis. NR1H4 variants may predispose to intrahepatic cholestasis of pregnancy (ICP). We report on NR1H4 analysis in eight patients with progressive familial intrahepatic cholestasis (PFIC) and in eight women with either ICP and/or drug-induced cholestasis (DIC) in whom no disease causing mutation in ATP8B1, ABCB11 and/or ABCB4 were found. No NR1H4 mutation was found in PFIC patients. In one woman with ICP/DIC, a NR1H4 heterozygous variant (c.-1G>T) was found. This suggests that a NR1H4 mutation is not or rarely involved in hepatocellular cholestasis of unknown cause. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  20. N2H4抑制好氧氨氧化及亚硝酸盐氧化动力学参数%Respirometric estimation of kinetics parameters for ammonium and nitrite oxidation under inhibition by N2H4

    Institute of Scientific and Technical Information of China (English)

    肖芃颖; 张代钧; 蔡庆

    2016-01-01

    The kinetic of CANON (completely autotrophic nitrogen removal over nitrite) process strengthened by trace hydrazine (N2H4) was investigated to provide fundamental data for further research and engineering application. Aerobic ammonium (NH4+) oxidation was divided into two steps, NH4+ oxidation to hydroxylamine step and hydroxylamine oxidation to nitrite step, and a startup functionNH2OH-bSaewas added to the former step todescribe the kinetic process of statup phase. Kinetics models for NH4+ and nitrite (NO2-) oxidation under N2H4inhibition was established and calibrated with the oxygen uptake rate (OUR) obtained in the respirometric tests. The biomass yield coefficients of AOB for NH2OH oxidation to NO2-(YNH2OH) and NH4+oxidation to NO2- (YNH4+) are estimated as (0.437±0.129)mgCOD/mgN and (0.324±0.0123)mgCOD/mgN, respectively. The biomass yield coefficient of NOB (YNO) is estimated as (0.222±0.0112)mgCOD/mgN. The half-saturation coefficient for N2H4 oxidation [KS,N2H4=(7.96±0.811)mgN/L], and kinitic inhibitor coefficients forNH4+ and NO2-oxidation by N2H4[KI,HON =(7.88±0.783)mgN/L,KI,NO=(1.223± 0.555)mgN/L, respectively] were first obtained by simulating the exogenous OUR profiles obtained in respirometric tests of nitrifying sludge at first time.%为联氨(N2H4)强化全自养脱氮(CANON, completely autotrophic nitrogen removal over nitrite)工艺性能研究提供基础数据,本研究将好氧氨氧化过程动力学表达分为两步,于氨(NH4+)氧化生成羟胺(NH2OH)步添加启动函数 NH2OH-bSae 用于模拟好氧氨氧化启动加速阶段,建立N2H4抑制好氧氨氧化与亚硝酸盐(NO2-)氧化过程动力学模型;采用呼吸测量法进行硝化污泥呼吸批次试验,分别得到 NH2OH 氧化生成NO2-和NH4+氧化生成NO2-的好氧氨氧化菌(AOB)产率系数[YNH2OH=(0.437±0.129)mgCOD/mgN,YNH4+=(0.324±0.0123)mgCOD/mgN]及亚硝酸盐氧化菌(NOB)产率系数[YNO=(0.222±0.0112)mgCOD/mgN];基于 N2H4抑制动力学模型模拟

  1. Titan's stratospheric C 2N 2, C 3H 4, and C 4H 2 abundances from Cassini/CIRS far-infrared spectra

    Science.gov (United States)

    Teanby, N. A.; Irwin, P. G. J.; de Kok, R.; Jolly, A.; Bézard, B.; Nixon, C. A.; Calcutt, S. B.

    2009-08-01

    Far-IR (25-50 μm, 200-400 cm -1) nadir and limb spectra measured during Cassini's four year prime mission by the Composite InfraRed Spectrometer (CIRS) instrument have been used to determine the abundances of cyanogen (C 2N 2), methylacetylene (C 3H 4), and diacetylene (C 4H 2) in Titan's stratosphere as a function of latitude. All three gases are enriched at northern latitudes, consistent with north polar subsidence. C 4H 2 abundances agree with those derived previously from mid-IR data, but C 3H 4 abundances are about 2 times lower, suggesting a vertical gradient or incorrect band intensities in the C 3H 4 spectroscopic data. For the first time C 2N 2 was detected at southern and equatorial latitudes with an average volume mixing ratio of 5.5±1.4×10 derived from limb data ( >3-σ significance). This limb result is also corroborated by nadir data, which give a C 2N 2 volume mixing ratio of 6±3×10 (2- σ significance) or alternatively a 3- σ upper limit of 17×10. Comparing these figures with photochemical models suggests that galactic cosmic rays may be an important source of N 2 dissociation in Titan's stratosphere. Like other nitriles (HCN, HC 3N), C 2N 2 displays greater north polar relative enrichment than hydrocarbons with similar photochemical lifetimes, suggesting an additional loss mechanism for all three of Titan's main nitrile species. Previous studies have suggested that HCN requires an additional sink process such as incorporation into hazes. This study suggests that such a sink may also be required for Titan's other nitrile species.

  2. A nucleosome turnover map reveals that the stability of histone H4 Lys20 methylation depends on histone recycling in transcribed chromatin.

    Science.gov (United States)

    Svensson, J Peter; Shukla, Manu; Menendez-Benito, Victoria; Norman-Axelsson, Ulrika; Audergon, Pauline; Sinha, Indranil; Tanny, Jason C; Allshire, Robin C; Ekwall, Karl

    2015-06-01

    Nucleosome composition actively contributes to chromatin structure and accessibility. Cells have developed mechanisms to remove or recycle histones, generating a landscape of differentially aged nucleosomes. This study aimed to create a high-resolution, genome-wide map of nucleosome turnover in Schizosaccharomyces pombe. The recombination-induced tag exchange (RITE) method was used to study replication-independent nucleosome turnover through the appearance of new histone H3 and the disappearance or preservation of old histone H3. The genome-wide location of histones was determined by chromatin immunoprecipitation-exonuclease methodology (ChIP-exo). The findings were compared with diverse chromatin marks, including histone variant H2A.Z, post-translational histone modifications, and Pol II binding. Finally, genome-wide mapping of the methylation states of H4K20 was performed to determine the relationship between methylation (mono, di, and tri) of this residue and nucleosome turnover. Our analysis showed that histone recycling resulted in low nucleosome turnover in the coding regions of active genes, stably expressed at intermediate levels. High levels of transcription resulted in the incorporation of new histones primarily at the end of transcribed units. H4K20 was methylated in low-turnover nucleosomes in euchromatic regions, notably in the coding regions of long genes that were expressed at low levels. This transcription-dependent accumulation of histone methylation was dependent on the histone chaperone complex FACT. Our data showed that nucleosome turnover is highly dynamic in the genome and that several mechanisms are at play to either maintain or suppress stability. In particular, we found that FACT-associated transcription conserves histones by recycling them and is required for progressive H4K20 methylation.

  3. Genomic comparison of Escherichia coli O104:H4 isolates from 2009 and 2011 reveals plasmid, and prophage heterogeneity, including shiga toxin encoding phage stx2.

    Directory of Open Access Journals (Sweden)

    Sanaa A Ahmed

    Full Text Available In May of 2011, an enteroaggregative Escherichia coli O104:H4 strain that had acquired a Shiga toxin 2-converting phage caused a large outbreak of bloody diarrhea in Europe which was notable for its high prevalence of hemolytic uremic syndrome cases. Several studies have described the genomic inventory and phylogenies of strains associated with the outbreak and a collection of historical E. coli O104:H4 isolates using draft genome assemblies. We present the complete, closed genome sequences of an isolate from the 2011 outbreak (2011C-3493 and two isolates from cases of bloody diarrhea that occurred in the Republic of Georgia in 2009 (2009EL-2050 and 2009EL-2071. Comparative genome analysis indicates that, while the Georgian strains are the nearest neighbors to the 2011 outbreak isolates sequenced to date, structural and nucleotide-level differences are evident in the Stx2 phage genomes, the mer/tet antibiotic resistance island, and in the prophage and plasmid profiles of the strains, including a previously undescribed plasmid with homology to the pMT virulence plasmid of Yersinia pestis. In addition, multiphenotype analysis showed that 2009EL-2071 possessed higher resistance to polymyxin and membrane-disrupting agents. Finally, we show evidence by electron microscopy of the presence of a common phage morphotype among the European and Georgian strains and a second phage morphotype among the Georgian strains. The presence of at least two stx2 phage genotypes in host genetic backgrounds that may derive from a recent common ancestor of the 2011 outbreak isolates indicates that the emergence of stx2 phage-containing E. coli O104:H4 strains probably occurred more than once, or that the current outbreak isolates may be the result of a recent transfer of a new stx2 phage element into a pre-existing stx2-positive genetic background.

  4. Regulation of CD11b transcription by decreasing PRC2 and increased acH4 level during ATRA-induced HL-60 differentiation

    Institute of Scientific and Technical Information of China (English)

    Huarong Tang; Fangping Chen; Qian Tan; Sanqin Tan; Linxin Liu; Fan Zhang

    2009-01-01

    Polycomb repressive complex 2 (PRC2),which mediates trimethylation of lysine 27 on histone H3 (K27me3),plays an important role in many types of stem cell differentiation.Here,we try to reveal how PRC2,PRC2-mediated repressive histone marker H3K27me3,and active histone marker histone H4 acetylation (acH4) regulate the CD11b transcription during all-trans retinoic acid (ATRA)-induced HL-60 leukemia cell differentiation.By using quantitative real-time polymerase chain reaction (qPCR) and western blot analysis,we found that the mRNA and protein expression levels of two members of PRC2 were decreased during ATRA-induced HL-60 differentiation,respectively.When treated with ATRA for 72 h,the EZH2 and SUZ12 mRNA levels were decreased to 35% and 38% of the control group,respectively.At the same time,the granulocytic mature surface marker CD11b expression was increased significantly at mRNA level detected by qPCR and protein level detected by flow cytometry.By using chromatin immunoprecipita-tion assay,we compared the local changes in SUZ12 binding and PRC2-mediated H3K27me3 at the promo-ter of CD11b during ATRA-induced HL-60 differ-entiation.Both the levels of SUZ12 binding and PRC2-mediated H3K27me3 at the promoter of CD11b were decreased for 4.1 and 3.8 folds,respectively.And we also found the increase in the acH4 level up to 4 folds after 72 h of ATRA treatment.These results suggested that the histone modification including PRC2-mediated repressive histone marker H3K27me3 and active histone marker acH4 may involve in CD11b transcription during HL-60 leukemia cells reprogram-ming to terminal differentiation.

  5. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H4Cl2 1,2-Dichloroethane (VMSD1212, LB4575_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H4Cl2 1,2-Dichloroethane (VMSD1212, LB4575_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  6. Genes and environment as predisposing factors in autoimmunity: acceleration of spontaneous thyroiditis by dietary iodide in NOD.H2(h4) mice.

    Science.gov (United States)

    Kolypetri, Panayota; King, Justin; Larijani, Mani; Carayanniotis, George

    2015-01-01

    In the field of autoimmune thyroiditis, NOD.H2(h4) mice have attracted significant and increasing attention since they not only develop spontaneous disease but they present thyroiditis with accelerated incidence and severity if they ingest iodide through their drinking water. This animal model highlights the interplay between genetic and dietary factors in the triggering of autoimmune disease and offers new opportunities to study immunoregulatory parameters influenced by both genes and environment. Here, we review experimental findings with this mouse model of thyroiditis.

  7. Genomic Comparison of Escherichia coli O104:H4 Isolates from 2009 and 2011 Reveals Plasmid, and Prophage Heterogeneity, Including Shiga Toxin Encoding Phage stx2

    Science.gov (United States)

    2012-11-01

    Testing Broth microdilution (SensititreH, Trek Diagnostics, Westlake, OH) was used to determine the minimum inhibitory concentra- tions (MIC) for 15...LB broth was inoculated with 3 to 4 isolated bacterial colonies and incubated at 37uC for 20 hours with shaking at 225 rpm. Three ml of each bacterial...Strain Description Source Reference 2011C–3493 Escherichia coli O104:H4, positive for stx2a, aggR, aatA, and fermentation of sorbitol, lactose and

  8. Heat of Mixing and Solution of 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (HMSD1111, LB3663_H)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'heat of Mixing and Solution of 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (HMSD1111, LB3663_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  9. Vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (EVLM1111, LB5653_E)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C6H10O Cyclohexanone (EVLM1111, LB5653_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  10. DFT study on structure, electronic properties, and reactivity of cis-isomers of [(NC5H4-S)2Fe(CO)2

    Indian Academy of Sciences (India)

    Charles A Mebi

    2011-09-01

    Three cis-isomers of [(NC5H4-S)2Fe(CO)2], models for the active site of [Fe] hydrogenase, have been examined by computational method at DFT B3LYP/6-311+G(d,p) level. The computed geometric parameters are remarkably close to experimental values. DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential, and electrophilicity) are calculated for the isomers and used to predict their relative stability and reactivity. The chemical reactivity indices are found to be related to the bond angle defined by the cis carbonyls and the iron center.

  11. First-principles investigations of the influence of alloying elements on the stability of Mg_2NiH_4%掺杂元素对Mg_2NiH_4稳定性影响的第一性原理研究

    Institute of Scientific and Technical Information of China (English)

    肖荣军; 郭进; 黄刚; 张秀彦; 朱基珍

    2009-01-01

    本文采用基于密度泛函理论(DFT)的第一原理赝势平面波(PW-PP)方法,计算了低温相Mg_2NiH_4和(Mg_2Ni,X)H_4(X=Ag, Al, Ti或Zr)的生成热及电子结构,分析了掺杂元素对Mg_2Ni氢化物稳定性的影响. 结果表明,掺杂导致了合金氢化物生成热的绝对值降低,合金氢化物的稳定性下降,且发现掺杂元素电负性越大,氢化物越不稳定. 从电子态密度图和Mulliken布居数分析知道,掺杂后合金氢化物释氢能力增强的主要原因在于Ni-H之间的成键减弱,以及掺杂元素诱导费米能级E_F处电子数浓度N(E_F)的增加.%The heat of formation and electronic structures of LT-Mg_2NiH_4 and (Mg_2Ni,X)H_4(X=Ag, Al, Ti or Zr) were calculated by plane wave pseudopotential (PW-PP) method which is based on density functional theory, and the influences of alloying elements on the stability of Mg_2Ni hydride were investigated. A low absolute value of the negative heat of formation of (Mg_2Ni,X)H_4(X=Ag, Al, Ti or Zr) compared with that of Mg_2NiH_4 indicates that the alloying atoms X(X=Ag, Al, Ti or Zr) befit to improve the dehydrogenating properties of Mg_2NiH_4. An interesting trend is found that, the more electronegative of alloying elements, the more unstability of hydride systems. According to the densities of states and Mulliken population analysis, it was found that the improvement of the dehydrogenating properties of Mg_2NiH_4 originates from the increasing of the densities of electron numbers N(E_F) at Fermi level (E_F) and the weaker bonding between Ni and H of (Mg_2Ni,X)H_4(X=Ag, Al, Ti or Zr) which is caused by the addition of Ag, Al, Ti or Zr atoms. Hence, the dehydrogenating properties of Mg_2NiH_4 are expected to be improved to a different extent by the addition of alloy elements.

  12. Space Group of Aquaimidazolemaleatozinc, [(H2O)(C3H4N2)(O2CCH=CHCO2Zn)]n

    Institute of Scientific and Technical Information of China (English)

    NG Seik Weng

    2005-01-01

    The space group of [(H2O)(C3H4N2)(O2CCH=CHCO2Zn)]n, which was originally described in the acentric Pc space group (Liu et al., Chin. J. Struct. Chem. 2004, 23, 160~163), is re-described in the centric P21/c space group.The crystal structure of (H2O)(C3H4N2)O2C-CH=CHCO2Zn was refined in the acentric Pc space group on 266 variables to R = 0.037 for the 1926 of the 2067 obeying the I > 2σ criterion[1]. The structure is better described in the centric P21/c space group (Table 1) as the two indepen-dent formula units are related by a center of symmetry. The 21 screw axis is must be pre-sent, as noted from the systematically absent 0k0 (k = 2n + 1) reflections in the 3302 reflections that were simulated[2, 3] from the published cell dimensions and atomic coordinates. Crystallo-graphica[4] estimates the hemisphere of reflections to be 3302, so that only a little more than the minimum monoclinic data must have been collec-ted in the study. A revision from Pc to P21/c is not particularly common[5] as the P21/c space group is uniquely determined from systematic absences. The polymeric chain propagates linearly along the c-axis of the unit cell (Fig. 1).

  13. Histone acetyl transferase 1 is essential for mammalian development, genome stability, and the processing of newly synthesized histones H3 and H4.

    Science.gov (United States)

    Nagarajan, Prabakaran; Ge, Zhongqi; Sirbu, Bianca; Doughty, Cheryl; Agudelo Garcia, Paula A; Schlederer, Michaela; Annunziato, Anthony T; Cortez, David; Kenner, Lukas; Parthun, Mark R

    2013-06-01

    Histone acetyltransferase 1 is an evolutionarily conserved type B histone acetyltransferase that is thought to be responsible for the diacetylation of newly synthesized histone H4 on lysines 5 and 12 during chromatin assembly. To understand the function of this enzyme in a complex organism, we have constructed a conditional mouse knockout model of Hat1. Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality. The lungs of embryos and pups genetically deficient in Hat1 were much less mature upon histological evaluation. The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress. Many of the Hat1(-/-) neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw. Hat1(-/-) mouse embryonic fibroblasts (MEFs) are defective in cell proliferation and are sensitive to DNA damaging agents. In addition, the Hat1(-/-) MEFs display a marked increase in genome instability. Analysis of histone dynamics at sites of replication-coupled chromatin assembly demonstrates that Hat1 is not only responsible for the acetylation of newly synthesized histone H4 but is also required to maintain the acetylation of histone H3 on lysines 9, 18, and 27 during replication-coupled chromatin assembly.

  14. Tuning optical properties of magic number cluster (SiO2)4O2H4 by substitutional bonding with gold atoms.

    Science.gov (United States)

    Cai, Xiulong; Zhang, Peng; Ma, Liuxue; Zhang, Wenxian; Ning, Xijing; Zhao, Li; Zhuang, Jun

    2009-04-30

    By bonding gold atoms to the magic number cluster (SiO(2))(4)O(2)H(4), two groups of Au-adsorbed shell-like clusters Au(n)(SiO(2))(4)O(2)H(4-n) (n = 1-4) and Au(n)(SiO(2))(4)O(2) (n = 5-8) were obtained, and their spectral properties were studied. The ground-state structures of these clusters were optimized by density functional theory, and the results show that in despite of the different numbers and types of the adsorbed Au atoms, the cluster core (SiO(2))(4)O(2) of T(d) point-group symmetry keeps almost unchanged. The absorption spectra were obtained by time-dependent density functional theory. From one group to the other, an extension of absorption wavelength from the UV-visible to the NIR region was observed, and in each group the absorption strengths vary linearly with the number of Au atoms. These features indicate their advantages for exploring novel materials with easily controlled tunable optical properties. Furthermore, due to the weak electronic charge transfer between the Au atoms, the clusters containing Au(2) dimers, especially Au(8)(SiO(2))(4)O(2), absorb strongly NIR light at 900 approximately 1200 nm. Such strong absorption suggests potential applications of these shell-like clusters in tumor cells thermal therapy, like the gold-coated silica nanoshells with larger sizes.

  15. Synthesis and Structure of [Cu(OH)2(H2O)2(4-C5H4N-COOH)2

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The hydrothermal reaction of isonicotinic acid (4-C5H4N-COOH), Cu(ClO4)2·6H2O and water at 170°C gave the title compound, [Cu(OH)2(H2O)2(4-C5H4N- COOH)2] (1), which was analyzed by single-crystal X-ray diffraction. The complex crystallizes in triclinic space group P ī with unit cell parameters: a = 6.337(2), b = 6.894(3), c = 9.178(3)?. ( = 99.40(3), ( = 105.26(3), ( = 108.17(5)°, V = 354.1(2) ?3, Z = 1, C12H16CuN2O8, Mr = 379.81, Dc = 1.791 Mg/m3, F(000) = 197, ((MoK() = 1.589 mm-1. The final R and wR are 0.068 and 0.170 for 1249 observed reflections with I ≥ 2σ(I). The central copper ion is in a distorted octahedron geometry completed by two nitrogen atoms from carboxylic ligand, two oxygen atoms from hydroxyl groups and two oxygen atoms from coordinated water molecules. The intermolecular hydrogen bonding leads to the formation of a three-dimensional supramolecular structure.

  16. Ru-η(6) -arene cations [{(Ph2 PC6 H4 )2 B(η(6) -Ph)}RuX](+) (X=Cl, H) as Lewis acids.

    Science.gov (United States)

    Boone, Michael P; Stephan, Douglas W

    2014-03-17

    The reactivity of [{(Ph2 PC6 H4 )2 B(η(6) -Ph)}RuCl][B(C6 F5 )4 ] (1) as a Lewis acid was investigated. Treatment of 1 with mono and multidentate phosphorus Lewis bases afforded the Lewis acid-base adducts with the ortho-carbon atom of the coordinated arene ring. Similar reactivity was observed upon treatment with N-heterocyclic carbenes; however, adduct formation occurred at both ortho- and para-carbon atoms of the bound arene with the para-position being favoured by increased steric demands. Interestingly treatment with isocyanides resulted in adduct formation with the B-centre of the ligand framework. The hydride-cation [{(Ph2 PC6 H4 )2 B(η(6) -Ph)}RuH] [B(C6 F5 )4 ] was prepared via reaction of 1 with silane. This species in the presence of a bulky phosphine behaves as a frustrated Lewis pair (FLP) to activate H2 between the phosphorus centre and the ortho-carbon atom of the η(6) -arene ring. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Upregulation of the mammalian X chromosome is associated with enhanced transcription initiation, MOF-mediated H4K16 acetylation, and longer RNA half-life

    Science.gov (United States)

    Deng, Xinxian; Berletch, Joel B.; Ma, Wenxiu; Nguyen, Di Kim; Noble, William S.; Shendure, Jay; Disteche, Christine M.

    2013-01-01

    SUMMARY X upregulation in mammals increases levels of expressed X-linked transcripts to compensate for autosomal bi-allelic expression. Here, we present molecular mechanisms that enhance X expression at transcriptional and posttranscriptional levels. Active mouse X-linked promoters are enriched in the initiation form of RNA polymerase II (PolII-S5p) and in specific histone marks including H4K16ac and histone variant H2AZ. The H4K16 acetyltransferase MOF, known to mediate the Drosophila X upregulation, is also enriched on the mammalian X. Depletion of MOF or MSL1 in mouse ES cells causes a specific decrease in PolII-S5p and in expression of a subset of X-linked genes. Analyses of RNA half-life datasets show increased stability of mammalian X-linked transcripts. Both ancestral X-linked genes, defined as those conserved on chicken autosomes, and newly acquired X-linked genes are upregulated by similar mechanisms but to a different extent, suggesting that subsets of genes are distinctly regulated dependent on their evolutionary history. PMID:23523075

  18. The influence hydrogen atom addition has on charge switching during motion of the metal atom in endohedral Ca@C60H4 isomers.

    Science.gov (United States)

    Raggi, G; Besley, E; Stace, A J

    2016-09-13

    Density functional theory has been applied in a study of charge transfer between an endohedral calcium atom and the fullerene cage in Ca@C60H4 and [Ca@C60H4](+) isomers. Previous calculations on Ca@C60 have shown that the motion of calcium within a fullerene is accompanied by large changes in electron density on the carbon cage. Based on this observation, it has been proposed that a tethered endohedral fullerene might form the bases of a nanoswitch. Through the addition of hydrogen atoms to one hemisphere of the cage it is shown that, when compared with Ca@C60, asymmetric and significantly reduced energy barriers can be generated with respect to motion of the calcium atom. It is proposed that hydrogen atom addition to a fullerene might offer a route for creating a bi-stable nanoswitch that can be fine-tuned through the selection of an appropriate isomer and number of atoms attached to the cage of an endohedral fullerene.This article is part of the themed issue 'Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene'.

  19. Improvement of the Tm3+:3H4 level lifetime in silica optical fibres by lowering the local phonon energy

    CERN Document Server

    Faure, Basile; Dussardier, Bernard; Monnom, Gérard; 10.1016/j.jnoncrysol.2007.05.025

    2010-01-01

    The role of some glass network modifiers on the quantum efficiency of the near-infrared fluorescence from the 3H4 level of Tm3+ ion in silica-based doped fibres is studied. Modifications of the core composition affect the spectroscopic properties of Tm3+ ion. Adding 17.4 mol% of AlO3/2 to the core glass caused an increase of the 3H4 level lifetime up to 50 $\\mu$s, 3.6 times higher than in pure silica glass. The quantum efficiency was increased from 2% to approximately 8%. On the opposite, 8 mol% of PO5/2 in the core glass made the lifetime decrease downto 9 $\\mu$s. These changes of Tm3+ optical properties are assigned to the change of the local phonon energy to which they are submitted by modifiers located in the vicinity of the doping sites. Some qualitative predictions of the maximum achievable quantum efficiency are possible using a simple microscopic model to calculate the non-radiative de-excitation rates.

  20. Carrier effects of dosing the h4iie cells with 3,3′,4,4tt´etrachlorobiphenyl (PCB77) in dimethyl sulfoxide or isooctane

    Science.gov (United States)

    Yu, Kyung O.; Fisher, Jeff W.; Burton, G. Allen; Tillitt, Donald E.

    1997-01-01

    A rat hepatoma cell line, H4IIE serves as a bioassay tool to assess the potential toxicity of dioxin-like chemicals, including polychlorinated biphenyls (PCB) in environmental samples. PCB exposure to these cells induces cytochrome (CYP) P4501A1 activity in a dose-dependent fashion, thus allowing assessment of mixtures. The objective of this study was to determine the effect of different carriers, dimethyl sulfoxide (DMSO) and isooctane on the concentrations of PCBs in the H411E cells and induction of CYPIA1 activity as measured by ethoxyresorufm O-deethylase (EROD) activity. H4IIE cells were dosed with three micrograms of UL-14C-PCB77/ plate dissolved in DMSO or isooctane, and were harvested at sequential time periods for 4 days. PCB77 concentration and EROD activity were measured in the cells. EROD activity was greater when using DMSO as compared to isooctane, while there was no difference in the distribution of PCB77-derived radioactivities within the cell culture system based upon the carrier solvent used to deliver PCB77.

  1. POLYMERIZATION OF p-DIETHYNYLBENZENE INITIATED BY Ni(C≡CC6H4C≡CH)2(PPH3)2

    Institute of Scientific and Technical Information of China (English)

    Mu-jie Yang; Xiao-wei Zhan

    2001-01-01

    Homogeneous polymerization ofp-diethynylbenzene initiated by nickel acetylide Ni(C≡CC6H4C≡CH)2(PPh3)2 has been investigated in terms of different solvents, addition agents, atmosphere gases, catalyst concentrations, monomer concentrations and polymerization temperatures. The yield and catalytic efficiency approach 88% and 11.1 kg polymer/mol Ni, respectively, under the optimum conditions: [cat] = 0.01 mol/L, [M] = 1.0 mol/L, NEt3/cat (mol ratio) = 3~5, 1,4dioxane/toluene (volume ratio) = 1 and T = 25℃ for 5 h. The polymerization rate equation can be expressed as Rp = kp[M][cat]2, where kp = 0.47 L2 * mol-2 * S-1 (25 ℃ ). The overall polymerization activation energy was found to be 203 kJ * mol-1. Poly(p-diethynylbenzene) so obtained is soluble in THF, CHCl3 and toluene with weight-average molecular weights as high as 27, 100 and a rich-trans extended π-conjugated polyene chain structure with pendent groups of p-C6H4C≡CH.

  2. Analysis of intermediate pressure SiH4/He capacitively coupled plasma for deposition of an amorphous hydrogenated silicon film in consideration of thermal diffusion effects

    Science.gov (United States)

    Kim, Ho Jun; Lee, Hae June

    2017-08-01

    To achieve rapid, uniform deposition of an amorphous hydrogenated silicon (a-Si:H) film, a capacitively coupled plasma (CCP) is often used at an intermediate pressure (>100 Pa), with a silane (SiH4)-based mixture. At these pressures, heavy particle interactions (such as ion-ion, ion-neutral, and neutral-neutral reactions) contribute significantly to the formation of precursor radicals. By adding a consideration of the thermal diffusion effects to the neutral transport equation, the chemical processes have been numerically analyzed with variation in the number fraction of SiH4 and electrode spacing using a two-dimensional fluid model of radio frequency discharges in a cylindrically symmetric CCP reactor. The non-uniformity of the deposition rate profiles increases consistently as electrode spacing increases, although the non-uniformity of the plasma parameters decreases with the increase of electrode spacing. The simulated deposition rate profiles match well with the experimental data for the change of electrode spacing. Based on the validation of our model, we propose predictive designs to potentially improve the reactor and process by modifying the thermal and electrical surface conditions.

  3. Dehydrogenation kinetics and reversibility of LiAlH4-LiBH4 doped with Ti-based additives and MWCNT

    Science.gov (United States)

    Thaweelap, Natthaporn; Utke, Rapee

    2016-11-01

    Dehydrogenation kinetics and reversibility of LiAlH4-LiBH4 doped with Ti-based additives (TiCl3 and Ti-isopropoxide), multiwall carbon nanotubes (MWCNT), and MWCNT impregnated with Ti-based additives are proposed. Reduction of dehydrogenation temperature as well as improvements of kinetics and reversibility, especially decomposition of thermodynamically stable hydride (LiBH4) is obtained from the samples doped with Ti-isopropoxide and MWCNT. This can be due to the fact that the formations of LixAl(1-x)B2 and LiH-Al containing phase during dehydrogenation favor decomposition of LiH, leading to increment of hydrogen capacity, and stabilization of boron in solid state, resulting in improvement of reversibility. Besides, the curvatures and thermal conductivity of MWCNT benefit hydrogen diffusion and heat transfer during de/rehydrogenation. Nevertheless, deficient hydrogen content reversible is observed in all samples due to the irreversible of LiAlH4 and/or Li3AlH6 as well as the formation of stable phase (Li2B12H12) during de/rehydrogenation.

  4. 配位氢化物LiAlH4/MgH2复合储氢材料体系放氢性能的研究

    Institute of Scientific and Technical Information of China (English)

    尹艳超; 郑姣姣; 李书涵

    2013-01-01

    实验采用工业用原料LiAlH4作为研究的主要材料,研究了LiAlH4/MgH2体系的放氢性能。结果表明,LiAlH4与MgH2摩尔比为1:0.5时,LiAlH4/MgH2体系的放氢量最大。并且随着LiAlH4与MgH2摩尔比的增大,试样的放氢量呈现出了一个逐步降低的趋势。

  5. Genome Sequencing and Genetic Analysis of H4N8 Subtype Avian Influenza Virus Isolated from Duck%一株鸭源H4N8亚型禽流感病毒的全基因测序及遗传进化分析

    Institute of Scientific and Technical Information of China (English)

    赵晴晴; 李群辉; 朱杰; 钟蕾; 刘晶晶; 顾敏; 王晓泉; 刘文博; 刘秀梵

    2015-01-01

    [Objective] Based on the difference of hemagglutinin (HA) and neuraminidase (NA), avian influenza viruses (AIVs) are classified into 16 hemagglutinin (HA) and 9 neuraminidase (NA) subtypes. According to the differences in pathogenicity, AIVs can be divided into highly pathogenic avian influenza virus (HPAIV) and low pathogenic avian influenza virus (LPAIV). H4 AIVs are low pathogenic influenza viruses which are generally produced asymptomatic infections in poultry. But H4 AIVs also has potential threats to both poultry and mammals. Strengthening investigation on H4 subtype avian influenza viruses is important for the study of evolution of AIVs. The objective of this experiment is to investigate the molecule characteristics and genetic evolution of H4 subtype avian influenza virus.[Method]One H4N8 subtype avian influenza virus, designated as A/duck/Nanjing/1102/2010 (H4N8) (DK/NJ/1102), was isolated from a live poultry market in eastern China during epidemiological surveillance in 2010. The complete genome sequences of the strain was sequenced and analyzed. The virus was identified by HA/HI test and RT-PCR test. The gene was cloned into pGEM-Teasy vector for sequencing, respectively. BLAST the nucleotide identity in GeneBank. The genome sequences of H4 subtype influenza viruses available in GeneBank and some other reference sequences were downloaded for genetic analysis .[Result]The results showed that the HA gene of DK/NJ/1102 had the highest nucleotide sequence identity of 98.9% with A/duck/Mongolia/274/2007(H4N3), and the amino acid sequence at the cleavage region of the HA gene was “P-E-K-A-S-R-G”, which is typical for low pathogenicity AIVs. NA gene had the highest nucleotide sequence identity of 98.8% with a duck-origin virus A/Duck/Eastern China/n91/2009 (H3N8) isolated from eastern China, whereas PB1, PA and NP genes were all mostly related with H1 subtype avian influenza viruses. The M gene shared the greatest nucleotide sequence identities (over 99

  6. Inelastic neutron scattering in Zr2NiH1.9 and Zr2NiH4.6

    Indian Academy of Sciences (India)

    R Mittal; S L Chaplot; P Raj; K Shashikala; A Sathyamoorthy

    2004-08-01

    In this paper we report the results obtained from inelastic neutron scattering measurements on Zr2NiH1.9 and Zr2NiH4.6 using triple-axis spectrometer at Dhruva reactor, Trombay. The spectrum up to 35 meV represents largely the lattice modes of Zr and Ni atoms. The vibrational frequencies of hydrogen atoms are expected predominantly at higher energies. The phonon spectra from 35–180 meV were recorded using a Be filter as analyser. In order to analyse the observed neutron spectra, we assume a set of Einstein modes due to the hydrogen atoms which are delta functions in energy. These delta functions are broadened by the resolution of the instrument. The vibrational frequencies obtained from the fitting of the observed phonon spectra have been assigned to various tetrahedral sites in both the compounds.

  7. Spectral studies of SiCl4 + N2O + Ar and SiH4 + Ar mixtures in a shock tube in 160-550 nm range

    Science.gov (United States)

    Park, C.; Fujiwara, T.

    1978-01-01

    Gases containing SiO, SiO2, SiH, and Si2 were produced in the reflected-shock region of a shock tube by heating SiCl4 + N2O + Ar and SiH4 + Ar mixtures with shock waves. Spectral absorption characteristics were measured in the 160-550 nm wavelength range and in the 2800-3600 K temperature range and compared to calculated values. The sums of the squares of electronic transition moments at equilibrium separation were derived. It was found that absorption by SiO2 and other known bands of SiO, SiH, and Si2 were too weak to be measured. The cross section of absorption by a continuum, believed due to SiH, varied from 2.5 x 10 to the -17th sq cm at 280 nm to 1.6 x 10 to the -18th sq cm at 440 nm.

  8. Insulin attenuates TNFα-induced hemopexin mRNA: An anti-inflammatory action of insulin in rat H4IIE hepatoma cells

    Directory of Open Access Journals (Sweden)

    J. Lee Franklin

    2017-03-01

    Full Text Available Proinflammatory cytokines, including TNF-α and IL-6, can contribute to insulin resistance. Conversely, insulin has some actions that can be considered anti-inflammatory. Hemopexin is a Class 2 acute phase reactant and control of its transcription is predominantly regulated by IL-6, with TNF-α and IL-1β also inducing hemopexin gene expression. Thus, we asked whether insulin could inhibit the ability of TNF-α to stimulate hemopexin mRNA expression. In cultured rat hepatoma (H4IIE cells, TNF-α significantly increased hemopexin mRNA accumulation. The TNF-α-induced increase of hemopexin mRNA was dramatically attenuated by insulin, even though TNF-α reduced peak insulin activation of ERK. Thus, even though TNF-α can contribute to insulin resistance, the residual insulin response was still able to counteract TNF-α actions.

  9. Measurements of (C-12)H4 nu-4 band halfwidths using a tunable diode laser system and a Fourier transform spectrometer

    Science.gov (United States)

    Devi, V. M.; Benner, D. C.; Rinsland, C. P.; Smith, M. A. H.

    1985-01-01

    Air-broadened and N2-broadened halfwidths at room temperature for twenty-five transitions in the nu-4 fundamental band of (C-12)H4 have been determined from IR absorption spectra recorded with a tunable diode laser spectrometer. Two tunable diode lasers operating in the 1250-1380-kayser region were used to obtain these data. Air-broadened halfwidths for twenty of these lines were also determined from additional spectra recorded at 0.01-kayser resolution with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak. The air-broadened halfwidths obtained from these two techniques are very consistent with agreement better than 3 percent in most cases.

  10. The effects of deposition temperature on the interfacial properties of SiH4 reduced blanket tungsten on TiN glue layer

    Science.gov (United States)

    Lee, Young J.; Park, Chong-Ook; Kim, Dong-Won; Chun, John S.

    1994-10-01

    Low pressure chemical vapor deposition tungsten films were deposited at various temperatures, using a WF6-SiH4-H2 gas mixture. The impurity distribution at the W/TiN interface was investigated by Auger electron spectroscopy depth profiling. Some fluorine accumulation at the interface is observed when the tungsten is deposited below 300°C. However, above 300°C, no accumulation of fluorine could be observed. A result obtained from thermodynamic calculations using SOLGASMIX-PV suggests that this phenomenon is closely associated with the highly oxidized surface layer of TiN at the initial stage of deposition. The reaction of the gas mixture with the TiN surface layer seems to enhance the fluorine accumulation, which lowers the adherence of the interface and increases the contact resistance.

  11. Theoretical study of the mechanism for C-H bond activation in spin-forbidden reaction between Ti+ and C2H4

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The mechanism of the spin-forbidden reaction Ti+(4F, 3d24s1) + C2H4 → TiC2H2+ (2A2) + H2 on both doublet and quartet potential energy surfaces has been investigated at the B3LYP level of theory. Crossing points between the potential energy surfaces and the possible spin inversion process are discussed by means of spin-orbit coupling (SOC) calculations. The strength of the SOC between the low-lying quartet state and the doublet state is 59.3 cm-1 in the intermediate complex IM1-4B2. Thus, the changes of its spin multiplicity may occur from the quartet to the doublet surface to form IM1- 2A1, leading to a sig-nificant decrease in the barrier height on the quartet PES. After the insertion intermediate IM2, two dis-tinct reaction paths on the doublet PES have been found, i.e., a stepwise path and a concerted path. The latter is found to be the lowest energy path on the doublet PES to exothermic TiC2H2+ (2A2) + H2 products, with the active barrier of 4.52 kcal/mol. In other words, this reaction proceeds in the following way: Ti++C2H4 →4IC→IM1-4B2→4,2ISC→IM1- 2A1→[2TSins]→IM2→[2TSMCTS]→IM5→TiC2H2+(2A2)+H2.

  12. Exploring the dynamics of reaction N((2)D)+C2H4 with crossed molecular-beam experiments and quantum-chemical calculations.

    Science.gov (United States)

    Lee, Shih-Huang; Chin, Chih-Hao; Chen, Wei-Kan; Huang, Wen-Jian; Hsieh, Chu-Chun

    2011-05-14

    We conducted the title reaction using a crossed molecular-beam apparatus, quantum-chemical calculations, and RRKM calculations. Synchrotron radiation from an undulator served to ionize selectively reaction products by advantage of negligibly small dissociative ionization. We observed two products with gross formula C(2)H(3)N and C(2)H(2)N associated with loss of one and two hydrogen atoms, respectively. Measurements of kinetic-energy distributions, angular distributions, low-resolution photoionization spectra, and branching ratios of the two products were carried out. Furthermore, we evaluated total branching ratios of various exit channels using RRKM calculations based on the potential-energy surface of reaction N((2)D)+C(2)H(4) established with the method CCSD(T)/6-311+G(3df,2p)//B3LYP/6-311G(d,p)+ZPE[B3LYP/6-311G(d,p)]. The combination of experimental and computational results allows us to reveal the reaction dynamics. The N((2)D) atom adds to the C=C π-bond of ethene (C(2)H(4)) to form a cyclic complex c-CH(2)(N)CH(2) that directly ejects a hydrogen atom or rearranges to other intermediates followed by elimination of a hydrogen atom to produce C(2)H(3)N; c-CH(2)(N)CH+H is the dominant product channel. Subsequently, most C(2)H(3)N radicals, notably c-CH(2)(N)CH, further decompose to CH(2)CN+H. This work provides results and explanations different from the previous work of Balucani et al. [J. Phys. Chem. A, 2000, 104, 5655], indicating that selective photoionization with synchrotron radiation as an ionization source is a good choice in chemical dynamics research.

  13. Synthesis and Characterization of [(C5H4SiMe2tBu)2Ln((-SnBu)]2 (Ln = Y, Er)1

    Institute of Scientific and Technical Information of China (English)

    LI Yan-Rong; ZHANG Zheng-Xing; CHEN Zhen-Xia; LIU Rui-Ting; ZHOU Xi-Geng

    2008-01-01

    (C5H4SiMe2tBu)2LnnBu reacted with 1 equiv. of elemental sulfur in toluene at ambient temperature to yield the corresponding lanthanocene thiolates [(C5H4SiMe2tBu)2Ln(m-SnBu)]2 (Ln = Y (1), Er (2)). Complexes 1 and 2 have been characterized by elemental analysis, IR, mass spectros- copy and X-ray single-crystal diffraction analysis. Both complexes are of monoclinic with space group P21/c, formula C52H94S2Si4Y2 1 (C52H94S2Si4Er2 2) Mr = 1073.57 (1230.27), a = 8.495(2) (8.41(2)), b = 26.913(8) (26.67(7)), c = 13.756(4) (13.68(4)) (A), α = 90(90), β = 101.184(5) (101.57(4)), γ = 90 (90)°, V = 3085.1(15) (3007(14))(A)3, Dc = 1.156 (1.359) g·cm-3, Z = 2 (2), F(000) = 1144 (1260), μ = 2.046 (2.951) cm-1, R = 0.0687 (0.0749) and wR = 0.1306 (0.1507) for observed reflections with I > 2σ(I). X-ray structures of 1 and 2 definitively prove that only one sulfur atom is inserted into the Ln-C(nBu) bond, forming a thiolate ligand.

  14. Decomposition reactions for NaAl H4 , Na3 Al H6 , and NaH: First-principles study

    Science.gov (United States)

    Ke, Xuezhi; Tanaka, Isao

    2005-01-01

    The electronic properties and lattice dynamics of the sodium alanate phases have been studied by the density functional calculations. The phases include NaAlH4 (space group, I41/a ), Na3AlH6 (space group, P21/n ), and NaH (space group, Fm-3m ). The electronic properties are discussed on the basis of the electronic band structures, the atomic charges, the bond overlap population analysis, and the Born effective charges. The phonon dispersion relations and phonon density of states (DOS) of the phases are calculated by a direct force-constant method. Within the quasiharmonic approximation, the calculated thermodynamic functions including the heat capacity, the vibrational enthalpy, and the vibrational entropy are in good agreement with experimental values. Three decomposition reactions are studied based on the thermodynamic functions. The reactions are (1) NaAlH4→(1)/(3)Na3AlH6+(2)/(3)Al+H2 , (2) (1)/(3)Na3AlH6→NaH+(1)/(3)Al+(1)/(2)H2 , and (3) NaH→Na+(1)/(2)H2 . The reactions (1), (2), and (3) are predicted to take place at 285, 390, and 726K , respectively, which are in good agreement with the experiment (353, 423, and 698K , respectively). The individual contributions to the reactions including the enthalpy and entropy are investigated. We found that the enthalpy for the reaction is almost constant, and the net entropy contribution ( TΔS ) to the reaction is approximately equal to the entropy contribution of the H2 gas molecule (produced in that reaction).

  15. Public health hazards in Poland posed by foodstuffs contaminated with [i]E.Coli[/i] O104:H4 bacterium from the recent European out break

    Directory of Open Access Journals (Sweden)

    Przemysław Biliński

    2012-03-01

    Full Text Available Shiga toxin producing [i]Escherichia coli[/i] (STEC are the most virulent diarrhoeagenic [i]E. coli [/i]known to date. They can spread with alarming ease via the food chain, as recently demonstrated by the large outbreak of STEC O104:H4 borne by sprouted seeds in 2011, clustered in northern Germany, and subsequently affecting other countries. Indeed, a significant number of infections to verocytotoxin producing [i]Escherichia coli[/i] O104:H4 have been reported from the WHO European Region resulting in many cases of bloody diarrhoea and haemolytic uraemic syndrome in Germany, 15 other European countries and North America. Eventually, the European Food Standards Agency, (EFSA, identified the likely source to a single consignment of fenugreek seeds from an Egyptian exporter as being linked to the two outbreaks in Germany and France. The situation was closely monitored by the Chief Sanitary Inspectorate public health authority in Poland where actions undertaken ensured that the public was well informed about the dangers of STEC contamination of food, how to avoid infection, and what to do if infected. Tracing the fenugreek distributors also enabled the identification of suspected batches and their isolation. As a result, there were very few reported cases of STEC infection in Poland. Effective control over such outbreaks is therefore a vital public health task. This should include early detection and rapid identification of the contagion mode, followed by removing the foodstuff(s from the market, providing consumer advice, and preventing secondary spreading. As a mitigation measure, screening/monitoring those involved in food handling is also warranted to exclude carriers who can be asymptomatic.

  16. Feedback Neural Network Power Transformer Fault Diagnosis Based on Classification of Fault Feature Gases and C2H2/C2H4 Ratio%基于故障特征气体与C2H2/C2H4比值分类的反馈型神经网络电力变压器故障诊断

    Institute of Scientific and Technical Information of China (English)

    黄祥柠; 马腾; 苏骏

    2014-01-01

    分析了五种特征气体及C2H2/C2H4的比值与变压器故障类型之间的关系,将变压器故障进行分类.依据C2H2/C2H4的比值将故障分为两类,第一类包含低温过热、中温过热、高温过热和局部放电,第二类包含低能放电、高能放电两类,并将C2H2/C2H4的比值过高的诊断为高能放电.再依据氢气对五种特征气体的百分比,从第一类中区分出局部放电.最后用反馈型神经网络中的Elman网络确定具体故障类型.

  17. Chemical dynamics of the CH(X2Π) + C2H4(X1A1g), CH(X2Π) + C2D4(X1A1g), and CD(X2Π) + C2H4(X1A1g) reactions studied under single collision conditions.

    Science.gov (United States)

    Zhang, Fangtong; Maksyutenko, Pavlo; Kaiser, Ralf I

    2012-01-14

    The crossed beam reactions of the methylidyne radical with ethylene (CH(X(2)Π) + C(2)H(4)(X(1)A(1g))), methylidyne with D4-ethylene (CH(X(2)Π) + C(2)D(4)(X(1)A(1g))), and D1-methylidyne with ethylene (CD(X(2)Π) + C(2)H(4)(X(1)A(1g))) were conducted at nominal collision energies of 17-18 kJ mol(-1) to untangle the chemical dynamics involved in the formation of distinct C(3)H(4) isomers methylacetylene (CH(3)CCH), allene (H(2)CCCH(2)), and cyclopropene (c-C(3)H(4)) via C(3)H(5) intermediates. By tracing the atomic hydrogen and deuterium loss pathways, our experimental data suggest indirect scattering dynamics and an initial addition of the (D1)-methylidyne radical to the carbon-carbon double bond of the (D4)-ethylene reactant forming a cyclopropyl radical intermediate (c-C(3)H(5)/c-C(3)D(4)H/c-C(3)H(4)D). The latter was found to ring-open to the allyl radical (H(2)CCHCH(2)/D(2)CCHCD(2)/H(2)CCDCH(2)). This intermediate was found to be long lived with life times of at least five times its rotational period and decomposed via atomic hydrogen/deuterium loss from the central carbon atom (C2) to form allene via a rather loose exit transition state in an overall strongly exoergic reaction. Based on the experiments with partially deuterated reactants, no compelling evidence could be provided to support the formation of the cyclopropene and methylacetylene isomers under single collision conditions. Likewise, hydrogen/deuterium shifts in the allyl radical intermediates or an initial insertion of the (D1)-methylidyne radical into the carbon-hydrogen/deuterium bond of the (D4)-ethylene reactant were found to be-if at all-of minor importance. Our experiments propose that in hydrocarbon-rich atmospheres of planets and their moons such as Saturn's satellite Titan, the reaction of methylidyne radicals should lead predominantly to the hitherto elusive allene molecule in these reducing environments.

  18. Insect γ-aminobutyric acid receptors and isoxazoline insecticides: toxicological profiles relative to the binding sites of [³H]fluralaner, [³H]-4'-ethynyl-4-n-propylbicycloorthobenzoate, and [³H]avermectin.

    Science.gov (United States)

    Zhao, Chunqing; Casida, John E

    2014-02-05

    Isoxazoline insecticides, such as fluralaner (formerly A1443), are noncompetitive γ-aminobutyric acid (GABA) receptor (GABA-R) antagonists with selective toxicity for insects versus mammals. The isoxazoline target in house fly ( Musca domestica ) brain has subnanomolar affinity for [³H]fluralaner and a unique pattern of sensitivity to isoxazolines and avermectin B(1a) (AVE) but not to fipronil and α-endosulfan. Inhibitor specificity profiles for 15 isoxazolines examined with Musca GABA-R and [³H]fluralaner, [³H]-4'-ethynyl-4-n-propylbicycloorthobenzoate ([³H]EBOB), and [³H]AVE binding follow the same structure-activity trends although without high correlation. The 3 most potent of the 15 isoxazolines tested in Musca [³H]fluralaner, [³H]EBOB, and [³H]AVE binding assays and in honeybee (Apis mellifera) brain [³H]fluralaner assays are generally those most toxic to Musca and four agricultural pests. Fluralaner does not inhibit [³H]EBOB binding to the human GABA-R recombinant β₃ homopentamer, which is highly sensitive to all of the commercial GABAergic insecticides. The unique isoxazoline binding site may resurrect the GABA-R as a major insecticide target.

  19. Suzuki-Miyaura, Mizoroki-Heck carbon-carbon coupling and hydrogenation reactions catalysed by PdII and RhI complexes containing cyclodiphosphazane cis-{tBuNP(OC6H4OMe-)}2

    Indian Academy of Sciences (India)

    Sasmita Mohanty; Maravanji S Balakrishna

    2010-03-01

    The catalytic activity of the palladium complex cis-[PdCl2{(tBuNP(OC6H4OMe-))2- }2] (2) containing cis-{tBuNP(OC6H4OMe-)}2 (1) in Suzuki-Miyaura and Mizoroki-Heck carbon-carbon cross coupling reactions is described. The compound 2 also displays very high activity in Mizoroki-Heck coupling reactions. The rhodium(I) complex [RhCl(COD){(tBuNP(OC6H4OMe-))2- }] (3) acts as an excellent catalyst for the hydrogenation of several terminal olefins.

  20. Comparison of the reactivity of 2-Li-C6H4CH2NMe2 with MCl4 (M=Th, U): isolation of a thorium aryl complex or a uranium benzyne complex.

    Science.gov (United States)

    Seaman, Lani A; Pedrick, Elizabeth A; Tsuchiya, Takashi; Wu, Guang; Jakubikova, Elena; Hayton, Trevor W

    2013-09-27

    Why do U react like that? Reaction of 2-Li-C6H4CH2NMe2 with [MCl4(DME)n] (M=Th, n=2; M=U, n=0) results in the formation of a thorium aryl complex, [Th(2-C6H4CH2NMe2)4] or a uranium benzyne complex, [Li][U(2,3-C6H3CH2NMe2)(2-C6H4CH2NMe2)3]. A DFT analysis suggests that the formation of a benzyne complex with U but not with Th is a kinetic and not thermodynamic effect.

  1. Synthesis and structure of the extended phosphazane ligand [(1,4-C6H4){N(μ-PN(t)Bu)2N(t)Bu}2](4).

    Science.gov (United States)

    Sevilla, Raquel; Less, Robert J; García-Rodríguez, Raúl; Bond, Andrew D; Wright, Dominic S

    2016-02-01

    The reaction of the phenylene-bridged precursor (1,4-C6H4)[N(PCl2)2]2 with (t)BuNH2 in the presence of Et3N gives the new ligand precursor (1,4-C6H4)[N(μ-N(t)Bu)2(PNH(t)Bu)2]2, deprotonation of which with Bu2Mg gives the novel tetraanion [(1,4-C6H4){N(μ-N(t)Bu)2(PN(t)Bu)2}2](4-).

  2. Propofol and magnesium attenuate isoflurane-induced caspase-3 activation via inhibiting mitochondrial permeability transition pore

    Directory of Open Access Journals (Sweden)

    Zhang Yiying

    2012-08-01

    Full Text Available Abstract Background The inhalation anesthetic isoflurane has been shown to open the mitochondrial permeability transition pore (mPTP and induce caspase activation and apoptosis, which may lead to learning and memory impairment. Cyclosporine A, a blocker of mPTP opening might attenuate the isoflurane-induced mPTP opening, lessening its ripple effects. Magnesium and anesthetic propofol are also mPTP blockers. We therefore set out to determine whether propofol and magnesium can attenuate the isoflurane-induced caspase activation and mPTP opening. Methods We investigated the effects of magnesium sulfate (Mg2+, propofol, and isoflurane on the opening of mPTP and caspase activation in H4 human neuroglioma cells stably transfected to express full-length human amyloid precursor protein (APP (H4 APP cells and in six day-old wild-type mice, employing Western blot analysis and flowcytometry. Results Here we show that Mg2+ and propofol attenuated the isoflurane-induced caspase-3 activation in H4-APP cells and mouse brain tissue. Moreover, Mg2+ and propofol, the blockers of mPTP opening, mitigated the isoflurane-induced mPTP opening in the H4-APP cells. Conclusion These data illustrate that Mg2+ and propofol may ameliorate the isoflurane-induced neurotoxicity by inhibiting its mitochondrial dysfunction. Pending further studies, these findings may suggest the use of Mg2+ and propofol in preventing and treating anesthesia neurotoxicity.

  3. B7-H4基因多态性与乳腺浸润性导管癌预后的相关性研究%Relationship between the polymorphisms of B7-H4 gene and the prognosis of breast infiltrative ductal carcinoma in Chinese Han females

    Institute of Scientific and Technical Information of China (English)

    李大林; 章婕; 傅振坤; 许凤燕; 李殿俊

    2010-01-01

    目的 探讨B7-H4基因rs10754339、rs10801935和rs3738414等单核苷酸多态性(SNP)位点多态性与黑龙江省妇女乳腺浸润性导管癌预后的相关性.方法 取280例乳腺浸润性导管癌患者的外周血提取基因组DNA,利用聚合酶链式反应限制性片段长度多态性(PCR-RFLP)技术进行B7-H4单核苷酸多态性检测,引用统计学软件分析基因多态性与患者临床指标(包括肿瘤大小,淋巴结转移,以及雌激素受体、孕激素受体和P53基因的表达)间的关系(卡方检验计算P值),进而确定该基因与黑龙江省汉族妇女乳腺癌预后的相关性.结果 B7-H4基因的rs10754339中,AA和AG基因型发生频率在雌激素受体表达阳性和阴性患者中有统计学差异(χ~2=4.06,P<0.05;χ~2=3.97,P<0.05),AA基因型和G等位基因发生频率在孕激素受体表达阳性和阴性患者中有显著差异(χ~2=4.74,P<0.05;χ~2=5.30,P<0.05).rs10801935中,AA基因型和C等位基因发生频率在孕激素受体表达阳性和阴性患者中有显著差异(χ~2=5.36,P<0.05;χ~2=5.90,P<0.05),而AC基因型发生频率在P53基因表达阳性和阴性患者中有显著差异(χ~2=5.82,P<0.05).结论 B7-H4基因多态性与乳腺浸润性导管癌患者雌激素受体,孕激素受体及P53基因的表达有关联,与乳腺癌患者的预后有一定相关性.%Objective To investigate the association between the polymorphisms of B7-H4 gene (in cluding rsl0754339, rs10801935 and rs3738414) and the prognosis of infiltrating ductal carcinoma in Chinese women of Heilongjiang province. Methods Two hundreds and eighty Chinese females with infiltrative ductal carcinoma were included in the study. The single nucleotide polymorphisms (SNPs) of rsl0754339, rsl0801935 and rs3738414 in B7-H4 gene were genotyped by PCR-RFLP. The association of the SNPs of B7 H4 gene with the clinical features of breast infiltrating ductal carcinoma (including tumor size, lymph node in volvement , and the expression status

  4. Two-dimensional fluid simulation on transient behavior and plasma uniformity in pulsed RF CCP sustained in SiH4 /N2/O2

    Science.gov (United States)

    Jia, Wen-Zhu; Wang, Xi-Feng; Song, Yuan-Hong; Wang, You-Nian

    2017-04-01

    Improving plasma uniformity during plasma processing in the microelectronics industry is of critical importance to the quality of etching or deposition. Compared to continuous wave (CW) plasmas, pulsed plasmas have drawn much attention with the introduction of additional pulse parameters, which would be helpful to improve the plasma properties. In this paper, a two-dimensional fluid model is developed to investigate a pulsed radio-frequency capacitively coupled plasma (CCP) sustained in SiH4/N2/O2 mixture at fixed operating conditions of 70V rf power, 300 mTorr (40 Pa) gas pressure and an SiH4/N2/O2 gas ratio of 2.5/92.5/5. First, we study the temporal dynamics of densities of the electron, positive ion and negative ion, at different positions in the pulsed CCP. Under the operation conditions, charged particles, instead of neutral particles, may basically respond to the applied modulated power. The electron density in the bulk could approach a quasi-steady value by the end of the activeglow. However, the achievement of a quasi-steady state of plasma like that in the CW condition not only depends on enough activeglow time of the pulse discharge but also relies on the observed position in the discharge. In addition, we investigate the impact of pulse parameters on plasma characteristics, showing that the radial inhomogeneity of plasma caused by the edge effect can be effectively suppressed by controlling the duty cycle (DC) rather than the pulse repetition frequency (PRF). Improvement of the plasma uniformity in pulsed discharge is due to the competition between the edge effects during the activeglow and diffusion of charged species during the afterglow. Moreover, the electron density undergoes a local minimum value in the temporal profile before it rises sharply beyond that of CW discharge, since production of electrons is less than loss by the spatial movement at the very beginning of one pulse. Also, there appears to be a peak value of ion bombardment energy at

  5. Picosecond real time study of the bimolecular reaction O(3P)+C2H4 and the unimolecular photodissociation of CH3CHO and H2CO

    Science.gov (United States)

    Abou-Zied, Osama K.; McDonald, J. Douglas

    1998-07-01

    The bimolecular reaction of O(3P) with ethylene and the unimolecular photodissociation of acetaldehyde and formaldehyde have been studied using a picosecond pump/probe technique. The bimolecular reaction was initiated in a van der Waals dimer precursor, C2H4ṡNO2, and the evolution of the vinoxy radical product monitored by laser-induced fluorescence. The NO2 constituent of the complex was photodissociated at 266 nm. The triplet oxygen atom then attacks a carbon atom of C2H4 to form a triplet diradical (CH2CH2O) which subsequently dissociates to vinoxy (CH2CHO) and H. The rise time of vinoxy radical production was measured to be 217 (+75-25) ps. RRKM theory was applied and a late high exit barrier was invoked in order to fit the measured rise time. The structure and binding energy of the van der Waals complex have been modeled using Lennard-Jones type potentials and the results were compared with other systems. The unimolecular side of the potential energy surfaces of this reaction has been investigated by photodissociating acetaldehyde at the same pump energy of 266 nm. The resulting photoproducts, acetyl radical (CH3CO) and formyl radical (HCO), have been monitored by resonance enhanced multiphoton ionization (REMPI) combined with a time-of-flight mass spectrometer. The similarity in the measured evolution times of both radicals indicates the same photodissociation pathway of the parent molecule. The photodissociation rate of acetaldehyde is estimated from RRKM theory to be very fast (3×1012s-1). The T1←S1 intersystem crossing (ISC) rate is found to be the rate determining step to photodissociation and increases with energy. The REMPI mechanism for the production of CH3CO+ is proposed to be the same as that of HCO+(2+1). The HCO product from the photodissociation of formaldehyde at 266 nm reveals a faster T1←S1 ISC rate than in acetaldehyde.

  6. Microwave-assisted Heterogeneous Photocatalytic Oxidation of Ethylene%C2H4的微波场助气相光催化氧化

    Institute of Scientific and Technical Information of China (English)

    郑宜; 付贤智; 李旦振

    2001-01-01

    用溶胶-凝胶法制备了多孔性TiO2和SO2-4/TiO2催化剂, 对其结构进行了表征, 并以C2H4为模型反应物考察了微波对催化剂的光催化氧化反应性能的影响. 在微波场中TiO2和SO2-4/TiO2催化剂的光催化氧化性能得到明显改善, 无微波场时乙烯转化率分别为20%(TiO2)和41%(SO2-4/TiO2), 而在微波辐射和紫外光的同时作用下乙烯转化率分别提高到27%和62%, SO2-4/TiO2催化剂的微波场助效应更为显著.%Porous TiO2 and SO2-4/TiO2 catalysts were prepared by sol-gel method and charaterized by XRD, N2 sorption analysis applying BET method, and microwave absorption spectrum. Photocatalytic oxidation of C2H4 in air stream was studied. The results showed that the photocatalytic activity of both SO2-4/TiO2 and TiO2 catalysts was obviously increased under the reaction condition of ultraviolet combined with microwave. The conversions of ethylene over TiO2 and SO2-4/TiO2 were enhanced from 20% and 41%(UV) to 27% and 62%(UV+MW), respectively. The effect of MW on SO2-4/TiO2 catalyst was more notable. The improvement on photocatalytic activity was attributed to the polarization effect of the highly defected catalysts in microwave field, which increased the transition probability of photon-generated electrons and decreased the electron-hole recombination on semiconductor surface.

  7. 恶性肿瘤的死亡风险与协同刺激分子B7-H4表达的关系%Association between expression of B7-H4 and death risk of malignant tumors

    Institute of Scientific and Technical Information of China (English)

    赵瑶; 蒋敬庭; 吴昌平; 刘银梅; 胡文斌; 沈月平

    2010-01-01

    Objective To evaluate the association between expression of B7-H4 and death risk of malignant tumors. Methods We searched the published papers in the PubMed, CNKI,Wanfang Database and Chinese Academic Journal, from 1999 to 2009 according to the developing searching program, inclusion criteria and exclusion criteria of the original literature. Taking into account the results of heterogeneity test using stata10. 1 software, fixed effect model or random effect model was chosen to calculate the combined hazard Ratio (HR) and its corresponding 95% confidence interval (CI), meanwhile publication bias was also evaluated. Results There were 35 papers searched, and only 6 entered Meta-analysis procedure. According to heterogeneity test results (x2 = 9. 61, df = 5 ,P >0.05 ), fixed effect model was used.The combined-HR was 1.42, and 95% CI was (1.16-1.72). Conclusion Higher B7-H4 expression is closely related to the death risk of the patients with cancer, and B7-H4 may be a negative regulatory molecules affecting the survival time of malignant tumor patients.%目的 探讨恶性肿瘤死亡风险与协同刺激分子B7-H4表达的关系.方法 制定原始文献的检索方案、纳入标准与排除标准,在PubMed与中国学术期刊网全文数据库(CNKI)、万方数据库、中文期刊上联合检索1999至2009年发表的论文.应用Stata 10.1软件对相关文献进行齐性检验,以(HR)值和95%CI为效应指标,根据一致性检验的结果,选择效应模型对HR值进行合并,并进行偏倚评估.结果 共检索到相关文献35篇,6篇进入Meta统计分析,异质性检验(x2=9.61,df=5,P>0.05),选择固定效应模型进行估计.多因素分析合并HR值为1. 42(95%CI为1.16~1.72).结论 协同刺激分子B7-H4高表达与恶性肿瘤患者死亡风险密切相关,B7-H4可能是影响恶性肿瘤患者长期生存的一个负性调节分子.

  8. SYNTHESIS OF NEW BIS(CYCLOPENTADIENYL)YTTRIUM COMPLEXES WITH ETHER FUNCTIONALIZED CYCLOPENTADIENYL LIGANDS - CRYSTAL-STRUCTURE OF [(C(5)H(4)CH(2)CH(2)OME)(2)Y(MU-H)(2)BH2

    NARCIS (Netherlands)

    LASKE, DA; DUCHATEAU, R; TEUBEN, JH; SPEK, AL

    1993-01-01

    Treatment of C(5)H(4)CH(2)CH(2)OMe.Li(TMEDA) (TMEDA = N, N, N', N' tetramethylethylenediamine) with half an equivalent of YCl3(THF)(3.5) in toluene afforded the salt- and solvent-free dimeric biscyclopentadienyl yttrium chloride [(C(5)H(4)CH(2)CH(2)OMe)(2)Y-(mu-Cl)](2) (1). Reaction of 1 with one eq

  9. One-Dimensional Stacking of Bifunctional Dithia- and Diselenadiazolyl Radicals : Preparation and Structural and Electronic Properties of 1,3-[(E2N2C)C6H4(CN2E2)] (E = S, Se)

    NARCIS (Netherlands)

    Andrews, M.P.; Douglass, D.C.; Fleming, R.M.; Glarum, S.H.; Haddon, R.C.; Marsh, P.; Oakley, R.T.; Palstra, T.T.M.; Schneemeyer, L.F.; Trucks, G.W.; Tycko, R.; Waszczak, J.V.; Young, K.M.; Zimmerman, N.M.; Cordes, A.W.

    1991-01-01

    The preparation and solid-state characterization of the 1,3-phenylene-bridged bis(dithiadiazolyl) and bis(diselenadiazolyl) diradicals 1,3-[(E2N2C)C6H4(CN2E2)] (E = S, Se) are reported. The isomorphous crystals of 1,3-[(E2N2C)C6H4(CN2E2)] so obtained are tetragonal, space group I41/a. Stacks of dira

  10. SYNTHESIS OF NEW BIS(CYCLOPENTADIENYL)YTTRIUM COMPLEXES WITH ETHER FUNCTIONALIZED CYCLOPENTADIENYL LIGANDS - CRYSTAL-STRUCTURE OF [(C(5)H(4)CH(2)CH(2)OME)(2)Y(MU-H)(2)BH2

    NARCIS (Netherlands)

    LASKE, DA; DUCHATEAU, R; TEUBEN, JH; SPEK, AL

    1993-01-01

    Treatment of C(5)H(4)CH(2)CH(2)OMe.Li(TMEDA) (TMEDA = N, N, N', N' tetramethylethylenediamine) with half an equivalent of YCl3(THF)(3.5) in toluene afforded the salt- and solvent-free dimeric biscyclopentadienyl yttrium chloride [(C(5)H(4)CH(2)CH(2)OMe)(2)Y-(mu-Cl)](2) (1). Reaction of 1 with one

  11. SYNTHESIS OF NEW BIS(CYCLOPENTADIENYL)YTTRIUM COMPLEXES WITH ETHER FUNCTIONALIZED CYCLOPENTADIENYL LIGANDS - CRYSTAL-STRUCTURE OF [(C(5)H(4)CH(2)CH(2)OME)(2)Y(MU-H)(2)BH2

    NARCIS (Netherlands)

    LASKE, DA; DUCHATEAU, R; TEUBEN, JH; SPEK, AL

    1993-01-01

    Treatment of C(5)H(4)CH(2)CH(2)OMe.Li(TMEDA) (TMEDA = N, N, N', N' tetramethylethylenediamine) with half an equivalent of YCl3(THF)(3.5) in toluene afforded the salt- and solvent-free dimeric biscyclopentadienyl yttrium chloride [(C(5)H(4)CH(2)CH(2)OMe)(2)Y-(mu-Cl)](2) (1). Reaction of 1 with one eq

  12. Expressions of costimulate molecules PD-L1, B7-H3 and B7-H4 in ovarian cancer and their significance%协同刺激分子PD-L1、B7-H3与B7-H4在卵巢癌中的表达及其意义

    Institute of Scientific and Technical Information of China (English)

    王丽; 吴昌平; 蒋敬庭

    2013-01-01

    PD-L1,B7-H3 and B7-H4 can bind to the receptors of T cells,leading to the inhibition of the proliferation and overactivation of T cells.PD-L1,B7-H3 and B7-H4 play negative modulation in cellular immune response and have been confirmed to be closely associated with immunogenicity.These three molecules do not express in normal ovary tissue but express strongly in ovarian cancer tissue,which enable the three molecules to be new tumor markers for diagnosing primary ovarian epithelial cancer.These three molecules are assumed to function in occurring and malignant transferring of ovarian cancer,and are valuable for diagnosing ovarian cancer in early stage and targeting therapy.%协同刺激分子PD-L1、B7-H3与B7-H4可与T细胞及其受体结合并抑制T细胞的增殖和过度活化,在细胞免疫应答过程中起重要的调控作用,已被多项研究证明与肿瘤的免疫原性及肿瘤的发生、发展密切相关.这3种分子在正常卵巢组织中均不表达,而在卵巢癌组织中呈不同程度的高表达,它们可能在促进卵巢癌的发生、转变及病情进展过程中起重要作用,研究其作用机制对卵巢癌的早期诊断及靶向治疗有一定的意义.

  13. Synthesis of 6,7-Methylenedioxy-9-methyl-1(2H,4H)-acridone%6,7-亚甲二氧基-9-甲基-1(2H,4H)-吖啶酮衍生物的合成

    Institute of Scientific and Technical Information of China (English)

    王文兰; 王春梅

    2004-01-01

    以5-芳基-1,3-环基环己二酮为原料合成了8个未见报道的吖啶酮衍生物,其结构均经元素分析,IR和1H NMR光谱确证.其中3-呋喃基-6,7-亚甲二氧基-9-甲基-1(2H,4H)-吖啶醇对一些肿瘤细胞有抑制作用.

  14. Synthesis, properties and crystal structure of (Gly) 2H 4SiW 12O 40·5.5H 2O

    Science.gov (United States)

    Lihua, Bi; Qizhuang, He; Qiong, Jia; Enbo, Wang

    2001-10-01

    A novel polyoxometalate containing Glycine (Gly), (Gly) 2H 4SiW 12O 40·5.5H 2O ( I), has been synthesized and characterized by single-crystal X-ray diffraction, elemental analyzes, IR spectrum, cyclic voltammograms and thermogravimetric analysis. The compound crystallizes in the monoclinic space group C2/ C with a=40.362 (8) Å, b=12.478 (3) Å, c=19.879 (4) Å, β=96.22 (3)°, V=9953 (4) Å 3, Z=8 and R1 ( wR2)=0.0699 (0.1609). The crystal structure consists of [SiW 12O 40] 4- units linked together with Gly molecules through hydrogen bonding. The electrochemical properties of I showed that the electrode reaction is surface-controlled. The compound has photosensitivity under irradiation of sunlight to result in charge transfer by oxidation of Gly and the reduction of SiW 12O 404-. We also found that the compound exhibited effectiveness in preventing cucumber mosaic virus (CMV).

  15. Solution structure of histone chaperone ANP32B: interaction with core histones H3-H4 through its acidic concave domain.

    Science.gov (United States)

    Tochio, Naoya; Umehara, Takashi; Munemasa, Yoshiko; Suzuki, Toru; Sato, Shin; Tsuda, Kengo; Koshiba, Seizo; Kigawa, Takanori; Nagai, Ryozo; Yokoyama, Shigeyuki

    2010-08-01

    Eukaryotic gene expression is regulated by histone deposition onto and eviction from nucleosomes, which are mediated by several chromatin-modulating factors. Among them, histone chaperones are key factors that facilitate nucleosome assembly. Acidic nuclear phosphoprotein 32B (ANP32B) belongs to the ANP32 family, which shares N-terminal leucine-rich repeats (LRRs) and a C-terminal variable anionic region. The C-terminal region functions as an inhibitor of histone acetylation, but the functional roles of the LRR domain in chromatin regulation have remained elusive. Here, we report that the LRR domain of ANP32B possesses histone chaperone activity and forms a curved structure with a parallel beta-sheet on the concave side and mostly helical elements on the convex side. Our analyses revealed that the interaction of ANP32B with the core histones H3-H4 occurs on its concave side, and both the acidic and hydrophobic residues that compose the concave surface are critical for histone binding. These results provide a structural framework for understanding the functional mechanisms of acidic histone chaperones.

  16. Protein arginine methyltransferase Prmt5-Mep50 methylates histones H2A and H4 and the histone chaperone nucleoplasmin in Xenopus laevis eggs.

    Science.gov (United States)

    Wilczek, Carola; Chitta, Raghu; Woo, Eileen; Shabanowitz, Jeffrey; Chait, Brian T; Hunt, Donald F; Shechter, David

    2011-12-01

    Histone proteins carry information contained in post-translational modifications. Eukaryotic cells utilize this histone code to regulate the usage of the underlying DNA. In the maturing oocytes and eggs of the frog Xenopus laevis, histones are synthesized in bulk in preparation for deposition during the rapid early developmental cell cycles. During this key developmental time frame, embryonic pluripotent chromatin is established. In the egg, non-chromatin-bound histones are complexed with storage chaperone proteins, including nucleoplasmin. Here we describe the identification and characterization of a complex of the protein arginine methyltransferase 5 (Prmt5) and the methylosome protein 50 (Mep50) isolated from Xenopus eggs that specifically methylates predeposition histones H2A/H2A.X-F and H4 and the histone chaperone nucleoplasmin on a conserved motif (GRGXK). We demonstrate that nucleoplasmin (Npm), an exceedingly abundant maternally deposited protein, is a potent substrate for Prmt5-Mep50 and is monomethylated and symmetrically dimethylated at Arg-187. Furthermore, Npm modulates Prmt5-Mep50 activity directed toward histones, consistent with a regulatory role for Npm in vivo. We show that H2A and nucleoplasmin methylation appears late in oogenesis and is most abundant in the laid egg. We hypothesize that these very abundant arginine methylations are constrained to pre-mid blastula transition events in the embryo and therefore may be involved in the global transcriptional repression found in this developmental time frame.

  17. PdBI Cold Dust Imaging of Two Extremely Red H-[4.5]>4 Galaxies Discovered with SEDS and CANDELS

    CERN Document Server

    Caputi, Karina I; Krips, Melanie; Geach, James E; Ashby, Matthew L N; Huang, Jiasheng; Fazio, Giovanni G; Koekemoer, Anton M; Popping, Gergo; Spaans, Marco; Castellano, Marco; Dunlop, James S; Fontana, Adriano; Santini, Paola

    2014-01-01

    We report Plateau de Bure Interferometer (PdBI) 1.1 mm continuum imaging towards two extremely red H-[4.5]>4 (AB) galaxies at z>3, which we have previously discovered making use of Spitzer SEDS and Hubble Space Telescope (HST) CANDELS ultra-deep images of the UDS field. One of our objects is detected on the PdBI map with a 4.3 sigma significance, corresponding to Snu(1.1mm)=(0.78 +/- 0.18) mJy. By combining this detection with the Spitzer 8 and 24 micron photometry for this source, and SCUBA2 flux density upper limits, we infer that this galaxy is a composite active galactic nucleus (AGN)/star-forming system. The infrared (IR)-derived star formation rate is SFR~(200 +/- 100) Msun/yr, which implies that this galaxy is a higher-redshift analogue of the ordinary ultra-luminous infrared galaxies (ULIRGs) more commonly found at z~2-3. In the field of the other target, we find a tentative 3.1 sigma detection on the PdBI 1.1 mm map, but 3.7 arcsec away of our target position, so it likely corresponds to a different ...

  18. Cloning, expression and characterization of a 46.5-kDa metallopeptidase from Bacillus halodurans H4 sharing properties with the pitrilysin family.

    Science.gov (United States)

    Dabonné, Soumaila; Moallic, Claire; Sine, Jean-Pierre; Niamké, Sébastien; Dion, Michel; Colas, Bernard

    2005-08-30

    A 1242 base pair DNA fragment from Bacillus halodurans H4 isolated from alkaline sediments of Lake Bogoria (Kenya) coding for a potential protease was cloned and sequenced. The hexa-histidine-tagged enzyme was overexpressed in Escherichia coli and was purified in one step by immobilized-metal affinity chromatography (IMAC) on Ni-NTA resin. The protease (ppBH4) presents an inverted zincin motif, HXXEH, which defines the inverzincin family. It shares several biochemical and molecular properties with the clan ME family M16 metallopeptidases (pitrilysins), as well as with database hypothetical proteins that are potential M16 family enzymes. Thus, like insulysin and nardilysin, but contrary to bacterial pitrilysin, ppBH4 is inactivated by sulfhydryl alkylating agents. On the other hand, like bacterial pitrilysin, ppBH4 is sensitive to reducing agents. The enzymatic activity of ppBH4 is limited to substrates smaller than proteins. In contrast to insulin, dynorphin and insulin B-chain are very good substrates for ppBH4 and several cleavage sites are common with those observed with well-characterized pitrilysins. As deduced from amino acid sequence, as well as determined by gel-filtration and SDS-polyacrylamide gel electrophoresis, ppBH4 is an active monomer of 46.5 kDa. This feature distinguishes ppBH4 from all other enzymes of the pitrilysin family so far described whose molecular masses range from 100 to 140 kDa.

  19. Control of branch formation in ethylene polymerization by a [Ni(h3-2-MeC3H4(diimine] PF6 / DEAC catalyst system

    Directory of Open Access Journals (Sweden)

    Escher Fernanda F. N.

    2001-01-01

    Full Text Available The polymerization of ethylene mediated by [Ni(eta³-2-MeC3H4{ArN=C(HC(H=NAr}] PF6, Ar = 2,6-C6H3iPr2 /DEAC catalyst precursor under mild reaction conditions (reaction temperature between -10 ºC and 25 ºC and ethylene pressure between 109 and 1520 kPa yields high molecular weight branched polyethylene. The degree of branching was modulated by a careful choice of reaction conditions. Thus, at 0 ºC and 109 kPa, the branching degree was 17 branches/1000 backbone carbon atoms and at 25 ºC, it went up to 90 branches/1000 backbone carbon atoms. The nature of the observed branches (methyl, ethyl and longer, their quantity and distribution along the polymer backbone chain can be rationalized in terms of a chain walking process and control of the extend of isomerization by the steric hindrance of the growing chain.

  20. Photocatalytic Degradation of Organic Dyes by H4SiW6Mo6O40/SiO2 Sensitized by H2O2

    Directory of Open Access Journals (Sweden)

    Li Yu

    2013-01-01

    Full Text Available H4SiW6Mo6O40/SiO2 was sensitized by H2O2 solution that significantly improved its catalytic activity under simulated natural light. Degradation of basic fuchsin was used as a probe reaction to explore the influencing factors on the photodegradation reaction. The results showed that the optimal conditions were as follows: initial concentration of basic fuchsin 8 mg/L, pH 2.5, catalyst dosage 4 g/L, and light irradiation time 4 h. Under these conditions, the degradation rate of basic fuchsin is 98%. The reaction of photocatalysis for basic fuchsin can be expressed as the first-order kinetic model. After being used continuously for four times, the catalyst kept the inherent photocatalytic activity for degradation of dyes. The photodegradation of malachite green, methyl orange, methylene blue, and rhodamine B were also tested, and the degradation rate of dyes can reach 90%–98%.

  1. Relationships of species of the Paramecium aurelia complex (Protozoa, Ph. Ciliophora, Cl. Oligohymenophorea) based on sequences of the histone H4 gene fragment.

    Science.gov (United States)

    Przyboś, Ewa; Maciejewska, Agnieszka; Skotarczak, Bogumiła

    2006-01-01

    A fragment ofhistone H4 gene (160 bp long) was sequenced in the standard strains of P. primaurelia (DQ067620), P. biaurelia (DQ067621), P. tetraurelia (DQ067622), P. pentaurelia (DQ067623), P. septaurelia (DQ067624), P. octaurelia (DQ067625), P. decaurelia (DQ067626), P. undecaurelia (DQ067627), P. dodecaurelia (DQ067628), P. tredecaurelia (DQ067629), and P. quadecaurelia (DQ067630). The tree constructed according to the Kimura model presents two main species clusters, one comprising P. undecaurelia, P. octaurelia, P. septaurelia, and the second cluster with P. pentaurelia, P. tredecaurelia, P. quadecaurelia, P. tetraurelia, P. decaurelia, P. primaurelia, P. biaurelia. P. dodecaurelia was recovered as a separate branch. The tree constructed on the basis of the maximum likelihood method also presents two species clusters, one with P. undecaurelia, P. octaurelia, P. septaurelia, and the second with P. primaurelia, P. decaurelia, P. pentaurelia, P. tredecaurelia, P. quadecaurelia, P. tetraurelia. P. biaurelia forms a basal clade to the latter cluster, and P. dodecaurelia was recovered as a clearly distinct branch from the clusters.

  2. Comparative study of RBE and cell survival fractions for $^{1}$H, $^{4}$He, $^{12}$C and $^{16}$O beams using Geant4 and Microdosimetric Kinetic model

    CERN Document Server

    Burigo, Lucas; Mishustin, Igor; Bleicher, Marcus

    2014-01-01

    Beams of $^{4}$He and $^{16}$O nuclei are considered for ion-beam cancer therapy as alternative options to protons and $^{12}$C nuclei. Spread-out Bragg peak (SOBP) distributions of physical dose and relative biological effectiveness for 10% survival are calculated by means of our Geant4-based Monte Carlo model for Heavy Ion Therapy (MCHIT) and the modified microdosimetric kinetic model. The depth distributions of cell survival fractions are calculated for $^{1}$H, $^{4}$He, $^{12}$C and $^{16}$O for tissues with normal (HSG cells), low and high radiosensitivity. In each case the cell survival fractions were compared separately for the target volume, behind and in front of it. In the case of normal radiosensitivity $^{4}$He and $^{12}$C better spare tissues in the entrance channel compared to protons and $^{16}$O. The cell survival fractions calculated, respectively, for the entrance channel and target volume are similar for $^{4}$He and $^{12}$C. When it is important to spare healthy tissues located after th...

  3. Meteorite search in the deflation basins in Lea County, New Mexico and Winkler County, Texas, USA: Discovery of Lea County 003 (H4)

    Energy Technology Data Exchange (ETDEWEB)

    Mikouchi, T; Buchanan, P C; Zolensky, M E; Welten, K C; Hutchison, R; Hutchison, M

    2000-01-14

    During the past few decades great numbers of meteorites have been recovered from the ice accumulation zones of Antarctica and from the vast Sahara. Although these two great deserts are the two most productive areas, the Southern High Plains in USA (New Mexico and Texas) and Nullarbor Plain, Western Australia have great potential for meteorite recovery. The number of meteorite finds from Roosevelt County, New Mexico alone exceeds 100 in only approximately 11 km{sup 2} area. Most meteorites from this area have been found on the floors of active deflation basins (blowouts) that have been excavated from a mantle of sand dunes. This area has no apparent fluvial or permafrost activity within the last 50,000 years, suggesting that only prevailing winds and natural aridity aid in the concentration and preservation of meteorites. The authors investigated these deflation surfaces in Lea County (the SE corner of New Mexico) and neighboring Winkler County, Texas following a prior search in this area which found two chondrites. They found a tiny H4 chondrite in this search and here they report its mineralogy and petrology along with preliminary data on its exposure history.

  4. Hydrothermal Synthesis and Crystal Structure of Inorganic-organic Hybrid Compound [H3NC2H4NH2]VOPO4

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An inorganic-organic hybrid compound, [H3NC2H4NH2]VOPO4 was synthesized by meansof the hydrothermal method. It was crystallized in a monoclinic system, a space group P21/c,with the crystal cell parameters: a=0. 922 85(11) nm, b=0. 729 94(9) nm, c=0. 984 95(11)nm, β=101. 280(3)°, V=0. 650 67(13) nm3, Mr=223.02 g/mol, Dc=2. 277 g/cm3, Z=4,R= 0. 031 5, ωR= 0. 086 5, GOF = 1. 085. The VO5N octahedra chains are corner-linked byPO4 tetrahedra; the VOsN octahedra are all trans-linked with V-O bonds being alternately short and long. The monoprotonated ethylenediamine was intercalated between the layers with one end coordinating to V and the other end as an H-bond donor interacting with a terminal O atom of PO4 from a neighboring sheet. The elementary analysis, infrared spectrum characters and thermal stability were also given.

  5. The highly virulent 2006 Norwegian EHEC O103:H25 outbreak strain is related to the 2011 German O104:H4 outbreak strain.

    Directory of Open Access Journals (Sweden)

    Trine M L'Abée-Lund

    Full Text Available In 2006, a severe foodborne EHEC outbreak occured in Norway. Seventeen cases were recorded and the HUS frequency was 60%. The causative strain, Esherichia coli O103:H25, is considered to be particularly virulent. Sequencing of the outbreak strain revealed resemblance to the 2011 German outbreak strain E. coli O104:H4, both in genome and Shiga toxin 2-encoding (Stx2 phage sequence. The nucleotide identity between the Stx2 phages from the Norwegian and German outbreak strains was 90%. During the 2006 outbreak, stx(2-positive O103:H25 E. coli was isolated from two patients. All the other outbreak associated isolates, including all food isolates, were stx-negative, and carried a different phage replacing the Stx2 phage. This phage was of similar size to the Stx2 phage, but had a distinctive early phage region and no stx gene. The sequence of the early region of this phage was not retrieved from the bacterial host genome, and the origin of the phage is unknown. The contaminated food most likely contained a mixture of E. coli O103:H25 cells with either one of the phages.

  6. Thermal Modification of a-SiC:H Films Deposited by Plasma Enhanced Chemical Vapour Deposition from CH4+SiH4 Mixtures

    Institute of Scientific and Technical Information of China (English)

    刘玉学; 王宁会; 刘益春; 申德振; 范希武; 李灵燮

    2001-01-01

    The effects of thermal annealing on photoluminescence (PL) and structural properties of a-Si1-xCx :H films deposited by plasma enhanced chemical vapour deposition from CH4+SiH4 mixtures are studied by using infrared, PL and transmittance-reflectance spectra. In a-SiC:H network, high-temperature annealing gives rise to the effusion of hydrogen from strongly bonded hydrogen in SiH, SiH2, (SiH2)n, SiCHn and CHn configurations and the break of weak C-C, Si-Si and C-Si bonds. A structural rearrangement will occur, which causes a significant correlation of the position and intensity of the PL signal with the annealing temperature. The redshift of the PL peak is related to the destruction of the confining power of barriers. However, the PL intensity does not have a significant correlation with the annealing temperature for a C-rich a-SiC:H network, which refers to the formation of π-bond cluster as increasing carbon content. It is indicated that the thermal stability of C-rich a-Si1-xCx:H films is better than that of Si-like a-Si1-xCx :H films.

  7. Synthesis and Crystal Structure of a One-dimensional Infinite Chain Organotin Complex [(n-Bu)3Sn(OCOC5H4NO)]n

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A novel organotin complex [(n-Bu)3Sn(OCOC5H4NO)]n has been synthesized and characterized by elemental analysis, IR and 1H NMR. The crystal structure has been determined by X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group P21/c with a =8.982(2), b = 17.908(4), c = 13.219(3) A, β= 96.981 (4)°, Z = 4, V= 2110.6(8) A3, Dc = 1.347 g/cm3,μ(MoKα) = 12.23 cm-1, F(000) = 880, R = 0.0497 and wR = 0.1263. In the molecular structure of the title complex, the tin atoms are five-coordinated in a distorted trigonal bipyramidal geometry. A one-dimensional linear polymer is formed through an interaction between the O atoms of pyridine-3-carboxylic acid N-oxide and tin atoms of an adjacent molecule.

  8. Synthesis and Crystal Structure of Bi(Hsal)3(1,10-phenanthroline)(Hsal=O2CC6H4-2-OH)

    Institute of Scientific and Technical Information of China (English)

    WANG Yong-Jing; XU Li

    2008-01-01

    A new bismuth compound Bi(Hsal)3(1,10-phenanthroline)(Hsal=O2CC6H4-2-OH)has been synthesized and characterized by single-crystal X-ray diffraction.It crystallizes in the triclinic system,space group P(-1),with a=10.243(2),b=11.905(3),c=12.934(3)(A),α=76.780(6),β=68.683(6),γ=80.930(7)°V=1425.6(5)(A)3,Dc=1.865g/cm3,Mr=800.51,F(000)=780,μ=6.247 mm-1,Z=2,R=0.0456 and wR=0.1131 for 5612 observed reflections(Ⅰ>2σ(Ⅰ)).In this compound,three salicylate ligands coordinate to the Bi atom through the carboxylate groups to form a four-membered chelate ring,and phenanthroline ligand chelates the metal through two N atoms. The structure of the title compound manifests a possible coordination mode between bismuth subsalicylate and N atom containing amino acid in the biological system.

  9. Linker Histone H1.2 Cooperates with Cul4A and PAF1 to Drive H4K31 Ubiquitylation-Mediated Transactivation

    Directory of Open Access Journals (Sweden)

    Kyunghwan Kim

    2013-12-01

    Full Text Available Increasing evidence suggests that linker histone H1 can influence distinct cellular processes by acting as a gene-specific regulator. However, the mechanistic basis underlying such H1 specificity and whether H1 acts in concert with other chromatin-altering activities remain unclear. Here, we show that one of the H1 subtypes, H1.2, stably interacts with Cul4A E3 ubiquitin ligase and PAF1 elongation complexes and that such interaction potentiates target gene transcription via induction of H4K31ubiquitylation, H3K4me3, and H3K79me2. H1.2, Cul4A, and PAF1 are functionally cooperative because their individual knockdown results in the loss of the corresponding histone marks and the deficiency of target gene transcription. H1.2 interacts with the serine 2-phosphorylated form of RNAPII, and we argue that it recruits the Cul4A and PAF1 complexes to target genes by bridging the interaction between the Cul4A and PAF1 complexes. These data define an expanded role for H1 in regulating gene transcription and illustrate its dependence on the elongation competence of RNAPII.

  10. Laser-initiated channels for ion transport: CO2-laser absorption and heating of NH3 and C2H4 gases

    Science.gov (United States)

    Olsen, J. N.

    1981-05-01

    Initiation and guiding of an electrical discharge by CO2-laser heating of a molecular gas can provide a channel suitable for the transport of a light ion beam for inertial-confinement fusion. We report absorption measurements for a CO2 laser tuned to the molecular vibrations of NH3 and C2H4 as a function of gas pressure, laser frequency, and laser energy density. The SATUR laser-gas-interaction code models the details of the absorption saturation process for NH3, calculating gas temperature in the process. The calculation is normalized to absorption data at 0.04 J/cm2 and tested with transmission measurements up to 15 J/cm2 into a 50-cm cell. These calculations are the basis for understanding the electrical breakdown and discharge evolution as observed and simulated in the following report. Of particular importance is the calculation of gas temperature of 1900-2100 °K for 15-35-J/cm2 incident laser energy density.

  11. The influence of surface structure on H4SiO4 oligomerization on rutile and amorphous TiO2 surfaces: an ATR-IR and synchrotron XPS study.

    Science.gov (United States)

    Song, Yantao; Swedlund, Peter J; McIntosh, Grant J; Cowie, Bruce C C; Waterhouse, Geoffrey I N; Metson, James B

    2012-12-11

    Silicic acid (H(4)SiO(4)) is ubiquitous in natural aquatic systems. Applications of TiO(2) in these systems will be influenced by H(4)SiO(4) sorption and oligomerization reactions on the TiO(2) surface, and this can affect many aspects of TiO(2) reactivity. The spatial arrangement of sorption sites on a metal oxide surface can promote specific lateral interactions, such as oligomerization, between sorbed species. In this work we explore the relationship between surface structure and interfacial H(4)SiO(4) oligomerization by quantifying the extent of H(4)SiO(4) sorption and oligomerization on three TiO(2) phases; a rutile phase having well-developed (110) faces (R180), a rutile phase with poorly developed (110) faces (R60), and an amorphous TiO(2) (TiO(2(am))). The in situ ATR-IR spectra measured over time as 0.2 mM H(4)SiO(4) reacted with TiO(2) were quite different on the three TiO(2) phases. The percentage of the surface H(4)SiO(4) that was present as oligomers increased over time on all phases, but after 20 h almost all H(4)SiO(4) on the R180 surface was oligomeric, while the H(4)SiO(4) on TiO(2(am)) was predominantly monomeric. The extent of H(4)SiO(4) oligomerization on R60 was intermediate. When the TiO(2) phases reacted with 1.5 mM H(4)SiO(4) the ATR-IR spectra showed oligomeric silicates dominating the surface of all three TiO(2) phases; however, after 20 h the percentage of the surface H(4)SiO(4) present as three-dimensional polymers was ∼30, 10, and 0% on R180, R60, and TiO(2(am)) respectively. The Si 2s photoelectron peak binding energy (BE) and the H(4)SiO(4) surface coverage (Γ(Si)) were measured by XPS over a range of Γ(Si). For any given Γ(Si) the Si 2s BE's were in the order R180 > R60 > TiO(2(am)). A higher Si 2s BE indicates a greater degree of silicate polymerization. The ATR-IR and XPS results support the existing model for interfacial H(4)SiO(4) oligomerization where linear trimeric silicates are formed by insertion of a solution H(4)SiO(4

  12. Organically templated uranium(IV) fluorooxalates with layer structures: (H4TREN)[U2F6(C2O4)3].4H2O (TREN = tris(2-aminoethyl)amine) and (H4APPIP)[U2F6(C2O4)3].4H2O (APPIP = 1,4-bis(3-amino-propyl)piperazine).

    Science.gov (United States)

    Wang, Chih-Min; Wu, Yi-Ying; Chen, Pei-Lin; Lii, Kwang-Hwa

    2007-03-14

    Two organically-templated layered uranium(IV) fluorooxalates, (H(4)TREN)[U(2)F(6)(C(2)O(4))(3)].4H(2)O (1) (TREN = tris(2-aminoethyl)amine) and (H(4)APPIP)[U(2)F(6)(C(2)O(4))(3)].4H(2)O (2) (APPIP = 1,4-bis(3-aminopropyl)piperazine), have been synthesized by hydrothermal methods and structurally characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic susceptibility. Both structures consist of anionic [U(2)F(6)(C(2)O(4))(3)](4-) layers separated by organic ammonium cations and lattice water molecules. The UF(3)O(6) polyhedra are connected by oxalate ligands in different ways within the layers. They are the first examples of organically-templated uranium fluorooxalates. Crystal data for compound 1 follow: monoclinic, P2(1)/c (No. 14), a = 19.1563(5) A, b = 8.9531(2) A, c = 16.6221(4) A, beta = 114.633(1) degrees, and Z = 4. Crystal data for compound are the same as those for 1 except a = 10.3309(8) A, b = 15.564(1) A, c = 17.537(1) A, and beta = 95.430(4) degrees.

  13. Electro- and magnetocommunication in [5,5]ditrovacenyls, [(eta7-C7H7)V(eta5-C5H4-X-eta5-C5H4)V(eta7-C7H7)], mediated by the spacers X = (Z)-CH=CH-, (E)-CH=CH-, > C=CH2, -CH2CH2-, and -CH2-.

    Science.gov (United States)

    Elschenbroich, Christoph; Plackmeyer, Jörn; Nowotny, Mathias; Behrendt, Andreas; Harms, Klaus; Pebler, Jürgen; Burghaus, Olaf

    2005-12-09

    Five new paramagnetic dinuclear complexes containing [5]trovacenyl groups, (eta7-C7H7)V(eta5-C5H4-), have been prepared and characterized, including by single-crystal X-ray diffraction. As intervening spacers, ethenediyl units in the geminal and vicinal (Z)- and (E)-bridging modes as well as methanediyl and ethanediyl units have been included with the aim of studying their propensity to transmit electric and magnetic information. It is found that redox splitting of consecutive electron-transfer steps is resolved for reduction (0-->1- -->2-) only, unsaturation of the C2 bridge not being requisite, since the -CH2CH2- spacer also gives rise to a small redox splitting. Magnetic communication is quantified in terms of the exchange coupling constant J, accessible from the EPR hyperfine pattern in solution and from magnetic susceptometry in the solid state. The results obtained from these methods generally differ; this fact is not surprising in view of conformational differences in the respective states of aggregation. It is concluded that orientation-dependent mechanisms of spin-spin interactions (pi-orbital overlap, hyperconjugation) contribute extensively although, as implied by sizeable J values for -CH2- and -C2H4- linked di[5]trovacenyl groups, coupling mediated by the sigma-orbital chain must also be considered.

  14. Synthesis of 1-[6-Fluoro-(2S)-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2- ethanediol and 1-[6-Fluoro-(2R)-3H,4H-dihydro-2H-2-chromenyl]- (1R)-1,2-ethanediol

    Institute of Scientific and Technical Information of China (English)

    YU,An-Guang; WANG,Nai-Xing; ZHANG,Jun-Ping; YANG,Yun-Xu; WANG,Wu-Wei; SHENG,Rui-Long

    2004-01-01

    @@ Benzopyran compounds possess diverse pharmacological properties such as β-blockade, anticonvulsant and antimicrobial.[1,2] Our interest has been focused on the synthesis of 1-[6-Fluoro-2S]-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2-ethanediol (6) and 1-[6-fluoro-(2R)-3H,4H-dihydro-2H-2-chromenyl]-(1R)-1,2-ethanediol (7) which are particularly convenient precursor to (S,R,R,R)-NE (8). 8 containing four asymmetrical carbon atoms was reported to be the most active isomer.[3] Chandrasekhar[4] has reported on the synthesis of 8. The key step to synthesize this compound is to obtain the chiral chromanone 6 and 7. 6 was accomplished in 8 steps by the Clasien rearrangement and a one-pot Sharpless asymmetric epoxidation, but the compound 7 was accomplished in 10 steps. Johannes[5] used Zr-catalytic kinetic resolution of allylic ethers and Mo-catalyzed chromene formation to synthesize 8 in 14 steps. However both of the methods request many synthetic steps and expensive reagents.

  15. 原位合成H4SiW12O40@C协同UV/H2O2降解罗丹明B模拟废水%Synergetic degradation of Rhodamine B in simulated wastewater using ultraviolet and hydrogen peroxide catalyzed by H4SiW12O40@C synthesized in situ

    Institute of Scientific and Technical Information of China (English)

    严平; 占昌朝; 曹小华; 谢宝华; 徐常龙; 张旭

    2015-01-01

    The H4SiW12O40@C photocatalysts synthesized in situ from silicadodecatungstic acid (SiW12) and soluble starch were studied and characterized by SEM,EDX,XRD,FTIR,UV-vis and BET in this research. The degradation of Rhodamine B (RhB) wastewater with H4SiW12O40@C photocatalysts and hydrogen peroxide was investigated under ultraviolet irradiation. The effects of different factors and synergetic effects on the degradation of RhB were investigated and the mechanism of catalytic oxidation of RhB was discussed. The results showed that the RhB was degraded efficiently. The decoloration efficiency of the RhB was up to 95.78% with the initial pH value of 3 and RhB concentration of 100mg/L under optimal reaction conditions (i.e. SiW20@C of 0.15g,dose of hydrogen peroxide concentration of 14mmol/L,reaction temperature of 25℃,the high pressure mercury lamp power of 500W,the radiation time of 70min). Degradation process of RhB wastewater by ultraviolet, hydrogen peroxide and SiW20@C had synergetic effects. UV-vis spectroscopy and HPLC results of the wastewater showed that the conjugating structure of RhB was destroyed,phenylcontained and small molecular compounds were included in the solution. In addition,the SiW20@C photocatalyst also showed good reusability.%以H4SiW12O40及可溶性淀粉为起始原料,原位合成了H4SiW12O40@C 光催化剂,并采用SEM、EDS、XRD、FTIR、UV-vis、BET对其进行了表征。对 H4SiW12O40@C协同UV/H2O2降解罗丹明B废水工艺进行了研究,考察了不同因素对降解效果的影响及协同效应,并探讨了催化氧化反应机理。研究结果表明:UV-SiW20@C-H2O2体系能高效快速降解废水中的罗丹明 B,产生了明显的协同效应。在优化工艺条件下,即在250mL初始 pH值为3、质量浓度为100mg/L的罗丹明B废水中,SiW20@C催化剂0.15g、H2O2浓度14mmol/L、温度25℃、高压汞灯功率500W、紫外照射70min条件下,罗丹明B脱色率达到了95.78%。紫外可见

  16. Fitness of Enterohemorrhagic Escherichia coli (EHEC)/Enteroaggregative E. coli O104:H4 in Comparison to That of EHEC O157: Survival Studies in Food and In Vitro.

    Science.gov (United States)

    Böhnlein, Christina; Kabisch, Jan; Meske, Diana; Franz, Charles M A P; Pichner, Rohtraud

    2016-11-01

    In 2011, one of the world's largest outbreaks of hemolytic-uremic syndrome (HUS) occurred, caused by a rare Escherichia coli serotype, O104:H4, that shared the virulence profiles of Shiga toxin-producing E. coli (STEC)/enterohemorrhagic E. coli (EHEC) and enteroaggregative E. coli (EAEC). The persistence and fitness factors of the highly virulent EHEC/EAEC O104:H4 strain, grown either in food or in vitro, were compared with those of E. coli O157 outbreak-associated strains. The log reduction rates of the different EHEC strains during the maturation of fermented sausages were not significantly different. Both the O157:NM and O104:H4 serotypes could be shown by qualitative enrichment to be present after 60 days of sausage storage. Moreover, the EHEC/EAEC O104:H4 strain appeared to be more viable than E. coli O157:H7 under conditions of decreased pH and in the presence of sodium nitrite. Analysis of specific EHEC strains in experiments with an EHEC inoculation cocktail showed a dominance of EHEC/EAEC O104:H4, which could be isolated from fermented sausages for 60 days. Inhibitory activities of EHEC/EAEC O104:H4 toward several E. coli strains, including serotype O157 strains, could be determined. Our study suggests that EHEC/EAEC O104:H4 is well adapted to the multiple adverse conditions occurring in fermented raw sausages. Therefore, it is strongly recommended that STEC strain cocktails composed of several serotypes, instead of E. coli O157:H7 alone, be used in food risk assessments. The enhanced persistence of EHEC/EAEC O104:H4 as a result of its robustness, as well as the production of bacteriocins, may account for its extraordinary virulence potential. In 2011, a severe outbreak caused by an EHEC/EAEC serovar O104:H4 strain led to many HUS sequelae. In this study, the persistence of the O104:H4 strain was compared with those of other outbreak-relevant STEC strains under conditions of fermented raw sausage production. Both O157:NM and O104:H4 strains could survive

  17. A two-dimensional yttrium phthalate coordination polymer, [Y4(H2O)2(C8H4O4)6]∞, exhibiting different coordination geometries

    Indian Academy of Sciences (India)

    A Thirumurugan; Srinivasan Natarajan

    2003-10-01

    A hydrothermal reaction of a mixture of Y(NO3)3, 1,2-benzenedicarboxylic acid (1,2-BDC) and NaOH gives rise to a new yttrium phthalate coordination polymer, [Y4(H2O)2(C8H4O4)6]∞, I. The Y ions in I are present in four different coordination environments with respect to the oxygen atoms (CN6 = octahedral, CN7 = pentagonal bipyramid, CN8 = dodecahedron and CN9 =capped square antiprism). The oxygen atoms of the 1,2-BDC are fully deprotonated, and show variations in their connectivity with Y atoms. The Y atoms themselves are connected through their vertices forming infinite Y-O-Y one-dimensional chains. The Y-O-Y chains are cross-linked by the 1,2-BDC anions forming a corrugated layer structure. The layers are supported by favourable $\\ldots$ interactions between the benzene rings of the 1,2-BDC anions. The variations in the coordination environment of the Y atoms and the presence of Y-O-Y interactions along with the favourable $\\ldots$ interactions between the benzene rings from different layers are noteworthy structural features. Crystal data: triclinic, space group = -1 (no. 2), = 12.6669 (2), = 13.8538 (2), = 16.0289 Å, = 75.20 (1), = 69.012 (1), = 65.529 (1)°, = 2371.28 (7) Å3, calc = 1.922 g cm-1, (MoK) = 4.943 mm-1. A total of 9745 reflections collected and merged to give 6566 unique reflections (int = 0.0292) of which 5252 with > 2() were considered to be observed. Final 2 = 0.0339, 2 = 0.0724 and =1.036 were obtained for 704 parameters.

  18. Protection of radiation-induced damage to the hematopoietic system, small intestine and salivary glands in rats by JNJ7777120 compound, a histamine H4 ligand.

    Directory of Open Access Journals (Sweden)

    Diego J Martinel Lamas

    Full Text Available Based on previous data on the histamine radioprotective effect on highly radiosensitive tissues, in the present work we aimed at investigating the radioprotective potential of the H4R ligand, JNJ7777120, on ionizing radiation-induced injury and genotoxic damage in small intestine, salivary glands and hematopoietic tissue. For that purpose, rats were divided into 4 groups. JNJ7777120 and JNJ7777120-irradiated groups received a daily subcutaneous JNJ7777120 injection (10 mg/kg starting 24 h before irradiation. Irradiated groups received a single dose of 5 Gy on whole-body using Cesium-137 source and were sacrificed 3 or 30 days after irradiation. Tissues were removed, fixed, stained with hematoxylin and eosin or PAS staining and histological characteristics were evaluated. Proliferative and apoptotic markers were studied by immunohistochemistry, while micronucleus assay was performed to evaluate DNA damage. Submandibular gland (SMG function was evaluated by methacholine-induced salivation. Results indicate that JNJ7777120 treatment diminished mucosal atrophy and preserved villi and the number of crypts after radiation exposure (240±8 vs. 165±10, P<0.01. This effect was associated to a reduced apoptosis and DNA damage in intestinal crypts. JNJ7777120 reduced radiation-induced aplasia, preserving medullar components and reducing formation of micronucleus and also it accelerated bone marrow repopulation. Furthermore, it reduced micronucleus frequency in peripheral blood (27±8 vs. 149±22, in 1,000 erythrocytes, P<0.01. JNJ7777120 completely reversed radiation-induced reduced salivation, conserving glandular mass with normal histological appearance and reducing apoptosis and atrophy of SMG. JNJ7777120 exhibits radioprotective effects against radiation-induced cytotoxic and genotoxic damages in small intestine, SMG and hematopoietic tissues and, thus, could be of clinical value for patients undergoing radiotherapy.

  19. Circulating microRNAs in patients with Shiga-Toxin-producing E. coli O104:H4 induced hemolytic uremic syndrome.

    Directory of Open Access Journals (Sweden)

    Johan M Lorenzen

    Full Text Available BACKGROUND: In early May 2011, an outbreak of hemorrhagic colitis associated with hemolytic-uremic syndrome (HUS first developed in Northern Germany and spread to 15 other countries in Europe. The outbreak-strain O104:H4, which combined virulence factors of typical enteroaggregative and Shiga-Toxin-producing E. coli was associated with an unusual high rate of hemolytic uremic syndrome. Also an unexpected high rate of coma and seizures leading to mechanical ventilation and ICU treatment was observed. MicroRNAs are small ribonucleotides orchestrating gene expression. We tested whether circulating microRNAs in serum of HUS patients during the 2011 epidemics are altered in this patient cohort and related to clinical manifestations. METHODOLOGY/PRINCIPAL FINDINGS: We profiled microRNAs using RNA isolated from serum of patients and healthy age-matched controls. The results were validated in 38 patients at baseline, 29 patients during follow-up and 21 age-matched healthy controls by miRNA-specific quantitative RT-PCR. Circulating levels of miR-24, miR-126 were increased in HUS patients versus controls. There was no association between these microRNAs and renal function or the need for renal replacement therapy. In contrast, levels of miR-126 were associated with neurological symptoms at baseline and during follow-up. In addition, miR-126 (on admission and miR-24 (on admission and during follow-up were associated with platelet count. CONCLUSIONS/SIGNIFICANCE: Circulating microRNAs are strongly altered in this patient cohort and associated with neurological symptoms as well as platelet count.

  20. High-resolution genetic analysis of the requirements for horizontal transmission of the ESBL plasmid from Escherichia coli O104:H4.

    Science.gov (United States)

    Yamaichi, Yoshiharu; Chao, Michael C; Sasabe, Jumpei; Clark, Lars; Davis, Brigid M; Yamamoto, Nozomi; Mori, Hiroshi; Kurokawa, Ken; Waldor, Matthew K

    2015-01-01

    Horizontal dissemination of the genes encoding extended spectrum beta-lactamases (ESBLs) via conjugative plasmids is facilitating the increasingly widespread resistance of pathogens to beta-lactam antibiotics. However, there is relatively little known about the regulatory factors and mechanisms that govern the spread of these plasmids. Here, we carried out a high-throughput, transposon insertion site sequencing analysis (TnSeq) to identify genes that enable the maintenance and transmission of pESBL, an R64 (IncI1)-related resistance plasmid that was isolated from Escherichia coli O104:H4 linked to a recent large outbreak of gastroenteritis. With a few exceptions, the majority of the genes identified as required for maintenance and transmission of pESBL matched those of their previously defined R64 counterparts. However, our analyses of the high-density transposon insertion library in pESBL also revealed two very short and linked regions that constitute a previously unrecognized regulatory system controlling spread of IncI1 plasmids. In addition, we investigated the function of the pESBL-encoded M.EcoGIX methyltransferase, which is also encoded by many other IncI1 and IncF plasmids. This enzyme proved to protect pESBL from restriction in new hosts, suggesting it aids in expanding the plasmid's host range. Collectively, our work illustrates the power of the TnSeq approach to enable rapid and comprehensive analyses of plasmid genes and sequences that facilitate the dissemination of determinants of antibiotic resistance.

  1. Application of laser induced electron impact ionization to the deposition chemistry in the hot-wire chemical vapor deposition process with SiH4-NH3 gas mixtures.

    Science.gov (United States)

    Eustergerling, Brett; Hèden, Martin; Shi, Yujun

    2007-11-01

    The application of a laser-induced electron impact (LIEI) ionization source in studying the gas-phase chemistry of the SiH(4)/NH(3) hot-wire chemical vapor deposition (HWCVD) system has been investigated. The LIEI source is achieved by directing an unfocused laser beam containing both 118 nm (10.5 eV) vacuum ultraviolet (VUV) and 355 nm UV radiations to the repeller plate in a time-of-flight mass spectrometer. Comparison of the LIEI source with the conventional 118 nm VUV single-photon ionization (SPI) method has demonstrated that the intensities of the chemical species with ionization potentials (IP) above 10.5 eV, e.g., H(2), N(2) and He, have been significantly enhanced with the incorporation of the LIEI source. It is found that the SPI source due to the 118 nm VUV light coexists in the LIEI source. This allows simultaneous observations of parent ions with enhanced intensity from VUV SPI and their "fingerprint" fragmentation ions from LIEI. It is, therefore, an effective tool to diagnose the gas-phase chemical species involved with both NH(3) and SiH(4) in the HWCVD reactor. In using the LIEI source to SiH(4), NH(3) and their mixtures, it has been shown that the NH(3) decomposition is suppressed with the addition of SiH(4) molecules. Examination of the NH(3) decomposition percentage and the time to reach the N(2) and H(2) steady-state intensities for various NH(3)/SiH(4) mixtures suggests that the extent of the suppression is enhanced with more SiH(4) content in the mixture. With increasing filament temperatures, the negative effect of SiH(4) becomes less important.

  2. Hydrogenation and Deuteration of C2H2 and C2H4 on Cold Grains: A Clue to the Formation Mechanism of C2H6 with Astronomical Interest

    Science.gov (United States)

    Kobayashi, Hitomi; Hidaka, Hiroshi; Lamberts, Thanja; Hama, Tetsuya; Kawakita, Hideyo; Kästner, Johannes; Watanabe, Naoki

    2017-03-01

    We quantitatively investigated the hydrogen addition reactions of acetylene (C2H2) and ethylene (C2H4) on amorphous solid water (ASW) at 10 and 20 K relevant to the formation of ethane (C2H6) on interstellar icy grains. We found that the ASW surface enhances the reaction rates for C2H2 and C2H4 by approximately a factor of 2 compared to those on the pure-solid C2H2 and C2H4 at 10 K, probably due to an increase in the sticking coefficient and adsorption energy of the H atoms on ASW. In contrast to the previous proposal that the hydrogenation rate of C2H4 is orders of magnitude larger than that of C2H2, the present results show that the difference in hydrogenation rates of C2H2 and C2H4 is only within a factor of 3 on both the surfaces of pure solids and ASW. In addition, we found the small kinetic isotope effect for hydrogenation/deuteration of C2H2 and C2H4 at 10 K, despite the requirement of quantum tunneling. At 20 K, the reaction rate of deuteration becomes even larger than that of hydrogenation. These unusual isotope effects might originate from a slightly larger number density of D atoms than H atoms on ASW at 20 K. The hydrogenation of C2H2 is four times faster than CO hydrogenation and can produce C2H6 efficiently through C2H4 even in the environment of a dark molecular cloud.

  3. CASSCF/CI calculations for first row transition metal hydrides - The TiH(4-phi), VH(5-delta), CrH(6-sigma-plus), MnH(7-sigma-plus), FeH(4,6-delta) and NiH(2-delta) states

    Science.gov (United States)

    Walch, S. P.; Bauschlicher, C. W., Jr.

    1983-01-01

    Calculations are performed for the predicted ground states of TiH(4-phi), VH(5-delta), CrH(6-sigma-plus), MnH(7-sigma-plus), Fett(4,6-delta) and NiH(2-delta). For FeH both the 6-delta and 4-delta states are studied, since both are likely candidates for the ground state. The ground state symmetries are predicted based on a combination of atomic coupling arguments and coupling of 4s(2)3d(n) and 4s(1)3d(n+1) terms in the molecular system. Electron correlation is included by a CASSCF/CI (SD) treatment. The CASSCF includes near-degeneracy effects, while correlation of the 3d electrons in included at the CI level.

  4. 催化剂对LiAlH4+MgH2体系放氢性能的影响及催化机理%Effect of catalysts on dehydrogenation of LiAlH4+MgH2 composite and catalytic mechanism

    Institute of Scientific and Technical Information of China (English)

    丁向前; 朱云峰; 卫灵君; 宦清清; 李李泉

    2013-01-01

    The LiAlH4+MgH2 composites doped with different catalysts were prepared by mechanical milling to improve the hydrogen desorption properties. Structural and dehydrogenation properties of the composites were investigated by XRD, SEM, EDS, XPS and Sieverts method. The catalytic mechanism of TiF3 was also discussed. The results show that doping with TiF3 decreases effectively the onset hydrogen desorption temperature, and increases the dehydrogenation kinetics of the composite. The TiF3­doped system exhibits the onset hydrogen desorption temperature of 84.1℃ and hydrogen desorption capacity (mass fraction) of 8.0%. The unknown Tix+­containing compound forms during thermal desorption of the composite, which promotes effectively the synergetic dehydrogenation of LiAlH4 and MgH2. In addition, the dehydrogenation activation energy Ea of the composite doped with TiF3 is calculated by JMA equation to be 79.1 kJ/mol, which is much lower than that of the composite without TiF3 addition (91.3 kJ/mol), indicating that TiF3 addition decreases greatly the kinetic barrier for dehydrogenation.%  采用机械球磨法在LiAlH4+MgH2体系中添加不同种类催化剂,以提高复合体系的放氢性能。运用XRD、SEM、EDS、XPS以及Sieverts法研究复合体系的结构以及放氢性能,并探讨TiF3的催化机理。结果表明:TiF3催化剂的添加显著降低了复合体系的起始放氢温度,提高了放氢动力学性能,该体系在84.1℃开始脱氢,放氢量(质量分数)达8.0%。热脱附过程中TiF3参与了反应,并生成含Tix+的未知化合物,有效地促进了LiAlH4和MgH2之间的协同放氢。复合体系掺杂TiF3后,其热脱附反应的活化能Ea为79.1 kJ/mol,与未添加TiF3的复合体系的活化能(91.3 kJ/mol)相比,TiF3的添加极大地降低了放氢反应动力学势垒。

  5. Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations.

    Science.gov (United States)

    Fabisch, Maria; Beulig, Felix; Akob, Denise M; Küsel, Kirsten

    2013-01-01

    We identified and quantified abundant iron-oxidizing bacteria (FeOB) at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7), to moderately acidic (R2, pH 4.4), to slightly acidic (R3, pH 6.3) in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U) bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic "Ferrovum myxofaciens" was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and "Ferrovum myxofaciens" revealed that ~72% (R2 sediment) and 37% (R3 sediment) of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

  6. Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

    Directory of Open Access Journals (Sweden)

    Maria eFabisch

    2013-12-01

    Full Text Available We identified and quantified abundant iron-oxidizing bacteria (FeOB at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7, to moderately acidic (R2, pH 4.4, to slightly acidic (R3, pH 6.3 in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic ‘Ferrovum myxofaciens’ was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and ‘Ferrovum myxofaciens’ revealed that approximately 72% (R2 sediment and 37% (R3 sediment of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

  7. Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

    Science.gov (United States)

    Fabisch, Maria; Beulig, Felix; Akob, Denise M.; Küsel, Kirsten

    2013-01-01

    We identified and quantified abundant iron-oxidizing bacteria (FeOB) at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7), to moderately acidic (R2, pH 4.4), to slightly acidic (R3, pH 6.3) in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U) bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic “Ferrovum myxofaciens” was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and “Ferrovum myxofaciens” revealed that ~72% (R2 sediment) and 37% (R3 sediment) of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

  8. Lateral variations of radiobiological properties of therapeutic fields of 1H, 4He, 12C and 16O ions studied with Geant4 and microdosimetric kinetic model

    Science.gov (United States)

    Dewey, Sophie; Burigo, Lucas; Pshenichnov, Igor; Mishustin, Igor; Bleicher, Marcus

    2017-07-01

    As known, in cancer therapy with ion beams the relative biological effectiveness (RBE) of ions changes in the course of their propagation in tissues. Such changes are caused not only by increasing the linear energy transfer (LET) of beam particles with the penetration depth towards the Bragg peak, but also by nuclear reactions induced by beam nuclei leading to the production of various secondary particles. Although the changes of RBE along the beam axis have been studied quite well, much less attention has been paid to the evolution of RBE in the transverse direction, perpendicular to the beam axis. In order to fill this gap, we simulated radiation fields of 1H, 4He, 12C and 16O nuclei of 20 mm in diameter by means of a Geant4-based Monte Carlo model for heavy-ion therapy connected with the modified microdosimetric kinetic model to describe the response of normal ((α/β)_x-rays=3.8 Gy) and early-responding ((α/β)_x-rays=10 Gy) tissues. Depth and radial distributions of saturation-corrected dose-mean lineal energy, RBE and RBE-weighted dose are investigated for passive beam shaping and active beam scanning. The field of 4He has a small lateral spread as compared with 1H field, and it is characterised by a modest lateral variation of RBE suggesting the use of fixed RBE values across the field transverse cross section at each depth. Reduced uncertainties of RBE on the boundary of a 4He treatment field can be advantageous in a specific case of an organ at risk located in lateral proximity to the target volume. It is found that the lateral distributions of RBE calculated for 12C and 16O fields demonstrate fast variations in the radial direction due to changes of dose and composition of secondary fragments in the field penumbra. Nevertheless, the radiation fields of all four projectiles at radii larger than 20 mm can be characterized by a common RBE value defined by tissue radiosensitivity. These findings can help, in particular, in accessing the transverse

  9. [Cu3(Hmesox)3]3-: a precursor for the rational design of chiral molecule-based magnets (H4mesox = 2-dihydroxymalonic acid).

    Science.gov (United States)

    Sanchiz, Joaquín; Pasán, Jorge; Fabelo, Oscar; Lloret, Francesc; Julve, Miguel; Ruiz-Pérez, Catalina

    2010-09-06

    Two new compounds K(3)[Cu(3)(Hmesox)(3)(H(2)O)] x 4 H(2)O (1) and {(PPh(4))(2)[CoCu(3)(Hmesox)(3)Cl]} (2) [H(4)mesox = mesoxalic acid (2-dihydroxymalonic acid) and PPh(4)(+) = tetraphenylphosphonium cation] have been prepared and magneto-structurally characterized. Compound 1 contains the [Cu(3)(Hmesox)(3)](3-) entity which can be considered as a new precursor for molecular magnetism. In 1 the triangular arrangement of three copper(II) ions bridged by alkoxo groups are further connected to a symmetry-related tricopper(II) unit through a double oxo(carboxylate) bridge. The resulting hexacopper(II) entities are joined further through anti-syn carboxylate groups into an anionic three-dimensional network of formula [Cu(3)(Hmesox)(3)(H(2)O)](n)(3n-) whose charge is neutralized by univalent potassium cations. The strong decrease of the chi(M)T product [per three copper(II) ions] in the high temperature range with the occurrence of a plateau for a spin doublet at T < 65 K is as expected for the coexistence of two antiferromagnetic interactions within the quasi isosceles tricopper(II) core of 1 [J = -194(1) cm(-1) and j = -3(4) cm(-1), the Hamiltonian being defined as H = -J(S(1) x S(2) + S(2) x S(3)) - j(S(1) x S(2))]. Compound 2 exhibits a chiral three-dimensional structure which is made up of an anionic [Co(II)Cu(II)(3)(mu(3)-Cl)(Hmesox)(3)](n)(2n-) framework with a (10,3)-a topology whose cavities are filled by PPh(4)(+) cations. The [Cu(II)(3)(mu(3)-Cl)(Hmesox)(3)](3-) tricopper(II) unit in 2 acts as a tris-bidentate ligand through the Hmesox groups toward three cobalt(II) ions, these latter ones being tris-chelated. Alternating current (ac) and direct current (dc) magnetic susceptibility measurements of 2 show a ferrimagnetic behavior with a magnetic ordering at T(c) = 18.5 K and a coercive field H(c) = 5000 G. As shown by the magneto-structural study of 2, the use as a ligand of 1 versus metal ions other than cobalt(II) or preformed complexes whose coordination

  10. Response of the extremely halophilic Halococcus dombrowskii strain H4 to UV radiation and space conditions in the EXPOSE -ADAPT project on the International Space Station

    Science.gov (United States)

    Fendrihan, Sergiu; Grosbacher, Michael; Stan-Lotter, Helga

    2010-05-01

    The international project ADAPT focuses on the response of different microorganisms to outer space conditions. In 2007, the European Space Agency (ESA) has installed the Columbus laboratory and the exposure facility EXPOSE-E on the International Space Station (ISS). One of the microorganisms that were exposed for 18 months on the ISS is Halococcus dombrowskii strain H4, an extremely halophilic archaeon which was isolated from about 250 million years old alpine salt deposits (1). Ground experiments with Hcc. dombrowskii included irradiation with different wavelengths and doses of UV, using a Hg low pressure lamp, a solar simulator SOL2 (both at the DLR, Cologne) and a Mars UV simulation lamp (2). Cells were embedded in halite crystals which were formed on quartz discs by evaporation of high salt buffers. Methods for analyzing the effects of exposure on Hcc. dombrowskii include the estimation of colony forming units (CFUs), staining for viability with the BacLight LIVE/DEAD kit (2), establishing long term liquid cultures and determination of the formation of cyclobutane pyrimidine dimers (CPDs) with specific antibodies (3). Counting of viable (green) and dead (red) cells showed an apparent preservation of viability following exposure to about 21 kJ/m2 in ground experiments, but the calculated D37 (dose of 37 % survival) for Hcc. dombrowskii was about 400 kJ/m2 in salt crystals (2). CPDs were detected in about 6-8% of cells of Hcc. dombrowskii following exposure to a dose of 3000 kJ/m2 (200-400 nm). Preliminary results with the samples of Hcc. dombrowskii from the ISS suggested preservation of cellular morphology and stainability with the fluorescent dyes of the LIVE/DEAD kit, as well as formation of CPDs in about 2-3 % of the cells. The determination of the survival of cells by measuring proliferation requires months of incubation; data can be expected in May or June 2010. (1) Stan-Lotter H, Pfaffenhuemer M, Legat A, Busse H-J, Radax C, Gruber C (2002) Halococcus

  11. 茂金属催化剂Cpt2MCl2(Cpt=tBuC5H4,M=Ti、zr、Hf)聚合丁烯-1的研究%Polymerization of Butene-1 Catalyzed byCpt2MCl2[Cpt=tBuC5H4,M=Ti(Ⅰ),Zr(Ⅱ),Hf(Ⅲ)

    Institute of Scientific and Technical Information of China (English)

    周光远; 程延祥; 金国新

    2001-01-01

    The synthesis and characterization of metallocene complexes Cpt2MC12[Cpt=tBuC5H4,M=Ti(Ⅰ), Zr(Ⅱ), Hr(Ⅲ)] are presented in catalyzation polymerization of butene-1. The metallocenecatalysts and polybutenes have been characterized by IR, 1H NMR and EI-MS spectra and DSCmeasurements. The catalytic features for butene-1 polymerization were studied under differentconditions. The results showed that Cpt2MCl2/MAO had high activity for butene-1 polymerization,improving the tacticity and molecular weight of the polymers obtained.%探讨了茂金属催化剂Cpt2MCl2(CPt=tBuC5H4,M=Ti,zr,Hf)的合成以及用于聚合丁烯-1的研究,研究了几种不同的茂金属催化剂和不同聚合条件下的催化行为,并通过IR、1H NMR、EI-MS、DSC、粘度法测分子量和正庚烷抽提等测试手段对催化剂和聚合物进行了表征.结果表明,叔丁基取代的茂金属催化剂催化丁烯-1聚合具有较高的催化活性,叔丁基的引入提高了聚合物的等规度和分子量.

  12. Syntheses,Spectroscopic Properties and Crystal Structures of (2-Cl-C6H4CH2)3SnS2CN(C5H10) and (2-Cl-C6H4CH2)3SnS2CN(C4H9N)

    Institute of Scientific and Technical Information of China (English)

    尹汉东; 王传华; 邢秋菊

    2004-01-01

    Two tri(2-chlorobenzyl)tin(IV) complexes with dithiocarbamate ligands (2-Cl- C6H4CH2)3SnS2CN(C5H10) 1 and (2-Cl-C6H4CH2)3SnS2CN(C4H9N) 2 have been synthesized by the reaction of tri(2-chlorobenzyl)tin(IV) chloride with dithiocarbamates and characterized by elemental analysis, IR and 1H NMR. The crystal structures were determined by X-ray single-crystal diffraction. The crystal of complex 1 belongs to triclinic, space group Pī with a = 9.121(5), b = 10.788(6), c = 15.549(8)(A), α = 77.812(6), β = 88.279(8), γ = 72.023(6)°, Z = 2, V = 1421.5(13) (A)3, Dc = 1.532 g/cm3, μ = 1.344 mm-1, F(000) = 660, R = 0.0382 and wR = 0.0984; and that of complex 2 is of monoclinic, space group P21/n with a = 13.892(10), b = 2.1274(8), c = 2.0553(15) (A), β = 107.145(11)°, Z = 4, V = 2726(3) (A)3, Dc = 1.600 g/cm3, μ = 1.403 mm-1, F(000) = 1320, R = 0.0361 and wR = 0.0826. Their structures show a distorted trigonal bipyramidal configuration with five- coordination for the central tin atoms.

  13. Induction by fructose force-feeding of histone H3 and H4 acetylation at their lysine residues around the Slc2a5 gene and its expression in mice.

    Science.gov (United States)

    Honma, Kazue; Mochizuki, Kazuki; Goda, Toshinao

    2013-01-01

    It has been reported that fructose force-feeding rapidly induced jejunal Slc2a5 gene expression in rodents. We demonstrate in this study that acetylation at lysine (K) 9 of histone H3 and acetylation at K5 and K16 of histone H4 were more enhanced in the promoter/enhancer to transcribed regions of the Slc2a5 gene in fructose force-fed mice than in glucose force-fed mice. However, fructose force-feeding did not induce acetylation at K14 of histone H3, or at K8 and K12 of histone H4 around the Slc2a5 gene. These results suggest that fructose force-feeding induced selective histone acetylation, particularly of H3 and H4, around the jejunal Slc2a5 gene in mice.

  14. Subdominant H60 antigen-specific CD8 T-cell response precedes dominant H4 antigen-specific response during the initial phase of allogenic skin graft rejection.

    Science.gov (United States)

    Yoo, Kang Il; Jeon, Ji Yeong; Ryu, Su Jeong; Nam, Giri; Youn, Hyewon; Choi, Eun Young

    2015-02-13

    In allogeneic transplantation, including the B6 anti-BALB.B settings, H60 and H4 are two representative dominant minor histocompatibility antigens that induce strong CD8 T-cell responses. With different distribution patterns, H60 expression is restricted to hematopoietic cells, whereas H4 is ubiquitously expressed. H60-specific CD8 T-cell response has been known to be dominant in most cases of B6 anti-BALB.B allo-responses, except in the case of skin transplantation. To understand the mechanism underlying the subdominance of H60 during allogeneic skin transplantation, we investigated the dynamics of the H60-specific CD8 T cells in B6 mice transplanted with allogeneic BALB.B tail skin. Unexpectedly, longitudinal bioluminescence imaging and flow cytometric analyses revealed that H60-specific CD8 T cells were not always subdominant to H4-specific cells but instead showed a brief dominance before the H4 response became predominant. H60-specific CD8 T cells could expand in the draining lymph node and migrate to the BALB.B allografts, indicating their active participation in the anti-BALB.B allo-response. Enhancing the frequencies of H60-reactive CD8 T cells prior to skin transplantation reversed the immune hierarchy between H60 and H4. Additionally, H60 became predominant when antigen presentation was limited to the direct pathway. However, when antigen presentation was restricted to the indirect pathway, the expansion of H60-specific CD8 T cells was limited, whereas H4-specific CD8 T cells expanded significantly, suggesting that the temporary immunodominance and eventual subdominance of H60 could be due to their reliance on the direct antigen presentation pathway. These results enhance our understanding of the immunodominance phenomenon following allogeneic tissue transplantation.

  15. Highly specific and rapid immuno-fluorescent visualization and detection of E. coli O104:H4 with protein-A coated magnetic beads based LST-MUG assay.

    Science.gov (United States)

    Barizuddin, Syed; Balakrishnan, Baskar; Stringer, R Cody; Dweik, Majed

    2015-08-01

    A method combining immunomagnetic separation and fluorescent sensing was developed to detect Escherichia coli (E. coli) O104:H4. The antibody specific to E. coli O104:H4 was immobilized on protein A-coated magnetic beads. This protein-A-anti E. coli O104:H4 complex was used to bind Fluorescein IsoThioCyanate (FITC) labeled E. coli O104:H4 antigen (whole cell) on it. The goal was to achieve a fluorescently detectable protein-A-anti E. coli O104:H4-E. coli O104:H4 complex on the magnetic beads. Fluorescent microscopy was used to image the magnetic beads. The resulting fluorescence on the beads was due to the FITC labeled antigen binding on the protein-A-anti E. coli O104:H4 immobilized magnetic beads. This visually proves the antigen-antibody binding. The fluorescent imaging results were obtained in 2 h if the minimum available bacteria in the sample were at least 10(5) CFU/ml. If no fluorescence was observed on the magnetic beads during fluorescent imaging, it indicates the bacterial concentration in the sample to be too low for it to have bound to the magnetic beads and hence no detection was possible. To detect bacterial concentration less than 10(5) CFU/ml in the sample, an additional step was required for detection. The magnetic bead complex was added to the LST-MUG (lauryl sulfate tryptose-4-methylumbelliferyl-β-D-glucuronide), a signaling reporter. The E. coli O104:H4 grows in LST-MUG and releases β-glucuronidase enzyme. This enzyme cleaves the MUG substrate that produces 4-methylumbelliferone, a highly fluorescent species. This fluorescence was detected using a spectrofluorometer. The emission peak in the fluorescent spectrum was found to be at 450 nm. The lower and upper detection range for this LST-MUG assay was found to be 2.05×10(5)-4.09×10(8) CFU/ml. The results for the LST-MUG assay for concentrations below 10(5) CFU/ml were ascertained in 8h. The advantages of this technique include the specific detection of bacteria without an enrichment step and

  16. The Cytoprotective Effects of E-α-(4-Methoxyphenyl-2',3,4,4'-Tetramethoxychalcone (E-α-p-OMe-C6H4-TMC--A Novel and Non-Cytotoxic HO-1 Inducer.

    Directory of Open Access Journals (Sweden)

    Kai B Kaufmann

    Full Text Available Cell protection against different noxious stimuli like oxidative stress or chemical toxins plays a central role in the treatment of many diseases. The inducible heme oxygenase isoform, heme oxygenase-1 (HO-1, is known to protect cells against a variety of harmful conditions including apoptosis. Because a number of medium strong electrophiles from a series of α-X-substituted 2',3,4,4'-tetramethoxychalcones (α-X-TMCs, X = H, F, Cl, Br, I, CN, Me, p-NO2-C6H4, Ph, p-OMe-C6H4, NO2, CF3, COOEt, COOH had proven to activate Nrf2 resulting in HO-1 induction and inhibit NF-κB downstream target genes, their protective effect against staurosporine induced apoptosis and reactive oxygen species (ROS production was investigated. RAW264.7 macrophages treated with 19 different chalcones (15 α-X-TMCs, chalcone, 2'-hydroxychalcone, calythropsin and 2'-hydroxy-3,4,4'-trimethoxychalcone prior to staurosporine treatment were analyzed for apoptosis and ROS production, as well as HO-1 protein expression and enzyme activity. Additionally, Nrf2 and NF-κB activity was assessed. We found that amongst all tested chalcones only E-α-(4-methoxyphenyl-2',3,4,4'-tetramethoxychalcone (E-α-p-OMe-C6H4-TMC demonstrated a distinct, statistically significant antiapoptotic effect in a dose dependent manner, showing no toxic effects, while its double bond isomer Z-α-p-OMe-C6H4-TMC displayed no significant activity. Also, E-α-p-OMe-C6H4-TMC induced HO-1 protein expression and increased HO-1 activity, whilst inhibition of HO-1 by SnPP-IX abolished its antiapoptotic effect. The only weakly electrophilic chalcone E-α-p-OMe-C6H4-TMC reduced the staurosporine triggered formation of ROS, while inducing the translocation of Nrf2 into the nucleus. Furthermore, staurosporine induced NF-κB activity was attenuated following E-α-p-OMe-C6H4-TMC treatment. Overall, E-α-p-OMe-C6H4-TMC demonstrated its effective cytoprotective potential via a non-toxic induction of HO-1 in RAW264

  17. Thermoelectric properties of the 3C, 2H, 4H, and 6H polytypes of the wide-band-gap semiconductors SiC, GaN, and ZnO

    OpenAIRE

    Zheng Huang; Tie-Yu Lü; Hui-Qiong Wang; Jin-Cheng Zheng

    2015-01-01

    We have investigated the thermoelectric properties of the 3C, 2H, 4H, and 6H polytypes of the wide-band-gap(n-type) semiconductors SiC, GaN, and ZnO based on first-principles calculations and Boltzmann transport theory. Our results show that the thermoelectric performance increases from 3C to 6H, 4H, and 2H structures with an increase of hexagonality for SiC. However, for GaN and ZnO, their power factors show a very weak dependence on the polytype. Detailed analysis of the thermoelectric prop...

  18. Molecular structure, optical and magnetic properties of metal-free phthalocyanine radical anions in crystalline salts (H2Pc˙-)(cryptand[2,2,2][Na(+)])·1.5C6H4Cl2 and (H2Pc˙-)(TOA+)·C6H4Cl2 (TOA+ is tetraoctylammonium cation).

    Science.gov (United States)

    Konarev, Dmitri V; Zorina, Leokadiya V; Khasanov, Salavat S; Litvinov, Aleksey L; Otsuka, Akihiro; Yamochi, Hideki; Saito, Gunzi; Lyubovskaya, Rimma N

    2013-05-21

    Ionic compounds containing radical anions of metal-free phthalocyanine (H2Pc˙(-)): (H2Pc˙(-))(cryptand[2,2,2][Na(+)])·1.5C6H4Cl2 (1) and (H2Pc˙(-))(TOA(+))·C6H4Cl2 (2) have been obtained as single crystals for the first time. Their crystal structures have been determined, and optical and magnetic properties have been investigated. The H2Pc˙(-) radical anions have a slightly bowl-like shape with four pyrrole nitrogen atoms located below the molecular plane, while four phenylene substituents are located above this plane. Changes in the average length of N-C and C-C bonds in H2Pc˙(-) in comparison with those in neutral H2Pc indicate that negative charge is mainly delocalized over the 24-atom phthalocyanine ring rather than the phenylene substituents. The H2Pc˙(-) formation is accompanied by a shift of up to 10 cm(-1) and disappearance of some intense IR-active bands whereas the band of the N-H stretching mode is shifted by 21-27 cm(-1) to larger wavenumbers. New bands attributed to H2Pc˙(-) appear in the NIR spectra of the salts with maxima at 1033 and 1028 nm for 1 and 2, respectively. The formation of H2Pc˙(-) is accompanied by the splitting of the Soret and Q-bands of H2Pc into several bands and their blue-shift up to 32 nm. Narrow EPR signals with g = 2.0033 and linewidth of 0.16-0.24 mT at room temperature in the spectra of the salts were attributed to the H2Pc˙(-) radical anions. According to SQUID measurements they have S = 1/2 spin states with effective magnetic moments of 1.73 (1) and 1.78 (2) μB at 300 K. Magnetic behavior of 1 and 2 follows the Curie-Weiss law with negative Weiss temperatures of -0.9 and -0.5 K, respectively, indicating weak antiferromagnetic interactions of spins. The EPR signal splits into two lines below 120 and 80 K for 1 and 2, respectively and these lines are noticeably broadened below 25 K.

  19. IR multiple-photon excitation of C2H5F and 1,1-C2H4F2 near dissociation threshold: vibrational emissions from parent and product species

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, J.F.; Wittig, C.

    1981-08-15

    The IR multiple photon excitation and dissociation of C2H5F and 1,1-C2H4F2 has been studied by monitoring vibrational fluorescence in the region 2000-4000 cm following excitation with the focused output from a CO2 TEA laser. 21 references, 2 figures.

  20. Effect of the CO2/SiH4 Ratio in the p-[mu]c-SiO:H Emitter Layer on the Performance of Crystalline Silicon Heterojunction Solar Cells

    National Research Council Canada - National Science Library

    Jaran Sritharathikhun; Taweewat Krajangsang; Apichan Moollakorn; Sorapong Inthisang; Amornrat Limmanee; Aswin Hongsingtong; Nattaphong Boriraksantikul; Tianchai Taratiwat; Nirod Akarapanjavit; Kobsak Sriprapha

    2014-01-01

    .... The reported work focused on the effects of the CO2/SiH4 ratio on the properties of p-μ c-SiO:H films and the effectiveness of the films as an emitter layer of crystalline silicon heterojunction (c-Si-HJ) solar cells. A p-μ c...

  1. Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra

    NARCIS (Netherlands)

    Marashdeh, A.; Frankcombe, T.J.

    2008-01-01

    The dehydrogenation enthalpies of Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4 have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski’s direct method. The dehydrog

  2. Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra.

    Science.gov (United States)

    Marashdeh, Ali; Frankcombe, Terry J

    2008-06-21

    The dehydrogenation enthalpies of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski's direct method. The dehydrogenation of Ca(AlH(4))(2) is exothermic, indicating a metastable hydride. Calculations for CaAlH(5) including ZPE effects indicate that it is not stable enough for a hydrogen storage system operating near ambient conditions. The destabilized combination of LiBH(4) with CaH(2) is a promising system after ZPE-corrected enthalpy calculations. The calculations confirm that including ZPE effects in the harmonic approximation for the dehydrogenation of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) has a significant effect on the calculated reaction enthalpy. The contribution of ZPE to the dehydrogenation enthalpies of Ca(AlH(4))(2) and CaAlH(5) calculated by the direct method phonon analysis was compared to that calculated by the frozen-phonon method. The crystal structure of CaAlH(5) is presented in the more useful standard setting of P2(1)c symmetry and the phonon density of states of CaAlH(5), significantly different to other common complex metal hydrides, is rationalized.

  3. Phosphinodi(benzylsilane) PhP{(o-C6H4CH2)SiMe2H}2: a versatile "PSi2Hx" pincer-type ligand at ruthenium.

    Science.gov (United States)

    Montiel-Palma, Virginia; Muñoz-Hernández, Miguel A; Cuevas-Chávez, Cynthia A; Vendier, Laure; Grellier, Mary; Sabo-Etienne, Sylviane

    2013-09-03

    The synthesis of the new phosphinodi(benzylsilane) compound PhP{(o-C6H4CH2)SiMe2H}2 (1) is achieved in a one-pot reaction from the corresponding phenylbis(o-tolylphosphine). Compound 1 acts as a pincer-type ligand capable of adopting different coordination modes at Ru through different extents of Si-H bond activation as demonstrated by a combination of X-ray diffraction analysis, density functional theory calculations, and multinuclear NMR spectroscopy. Reaction of 1 with RuH2(H2)2(PCy3)2 (2) yields quantitatively [RuH2{[η(2)-(HSiMe2)-CH2-o-C6H4]2PPh}(PCy3)] (3), a complex stabilized by two rare high order ε-agostic Si-H bonds and involved in terminal hydride/η(2)-Si-H exchange processes. A small free energy of reaction (ΔrG298 = +16.9 kJ mol(-1)) was computed for dihydrogen loss from 3 with concomitant formation of the 16-electron species [RuH{[η(2)-(HSiMe2)-CH2-o-C6H4]PPh[CH2-o-C6H4SiMe2]}(PCy3)] (4). Complex 4 features an unprecedented (29)Si NMR decoalescence process. The dehydrogenation process is fully reversible under standard conditions (1 bar, 298 K).

  4. The PR-Set7 binding domain of Riz1 is required for the H4K20me1-H3K9me1 trans-tail 'histone code' and Riz1 tumor suppressor function.

    Science.gov (United States)

    Congdon, Lauren M; Sims, Jennifer K; Tuzon, Creighton T; Rice, Judd C

    2014-04-01

    PR-Set7/Set8/KMT5a is the sole histone H4 lysine 20 monomethyltransferase (H4K20me1) in metazoans and is essential for proper cell division and genomic stability. We unexpectedly discovered that normal cellular levels of monomethylated histone H3 lysine 9 (H3K9me1) were also dependent on PR-Set7, but independent of its catalytic activity. This observation suggested that PR-Set7 interacts with an H3K9 monomethyltransferase to establish the previously reported H4K20me1-H3K9me1 trans-tail 'histone code'. Here we show that PR-Set7 specifically and directly binds the C-terminus of the Riz1/PRDM2/KMT8 tumor suppressor and demonstrate that the N-terminal PR/SET domain of Riz1 preferentially monomethylates H3K9. The PR-Set7 binding domain was required for Riz1 nuclear localization and maintenance of the H4K20me1-H3K9me1 trans-tail 'histone code'. Although Riz1 can function as a repressor, Riz1/H3K9me1 was dispensable for the repression of genes regulated by PR-Set7/H4K20me1. Frameshift mutations resulting in a truncated Riz1 incapable of binding PR-Set7 occur frequently in various aggressive cancers. In these cancer cells, expression of wild-type Riz1 restored tumor suppression by decreasing proliferation and increasing apoptosis. These phenotypes were not observed in cells expressing either the Riz1 PR/SET domain or PR-Set7 binding domain indicating that Riz1 methyltransferase activity and PR-Set7 binding domain are both essential for Riz1 tumor suppressor function.

  5. The PR-Set7 binding domain of Riz1 is required for the H4K20me1-H3K9me1 trans-tail ‘histone code’ and Riz1 tumor suppressor function

    Science.gov (United States)

    Congdon, Lauren M.; Sims, Jennifer K.; Tuzon, Creighton T.; Rice, Judd C.

    2014-01-01

    PR-Set7/Set8/KMT5a is the sole histone H4 lysine 20 monomethyltransferase (H4K20me1) in metazoans and is essential for proper cell division and genomic stability. We unexpectedly discovered that normal cellular levels of monomethylated histone H3 lysine 9 (H3K9me1) were also dependent on PR-Set7, but independent of its catalytic activity. This observation suggested that PR-Set7 interacts with an H3K9 monomethyltransferase to establish the previously reported H4K20me1-H3K9me1 trans-tail ‘histone code’. Here we show that PR-Set7 specifically and directly binds the C-terminus of the Riz1/PRDM2/KMT8 tumor suppressor and demonstrate that the N-terminal PR/SET domain of Riz1 preferentially monomethylates H3K9. The PR-Set7 binding domain was r