11 research outputs found

    syn,syn-15,17-Di-2-naphthyl­hexa­cyclo­[10.2.1.13,10.15,8.02,11.04,9]hepta­decane deuterochloro­form monosolvate

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    The main molecule of the title compound, C37H36·CDCl3, is a hydro­carbon with two naphthalene segments attached to opposite ends of a rigid norbornylogous spacer with an overall structure that is approximately C-shaped. The dihedral angle between the naphthalene ring planes is 9.27 (7)°. The cleft that exists between the naphthalene rings is large enough that the compound crystallizes with a solvent mol­ecule (CDCl3) in the cleft. The CDCl3 solvent mol­ecule is present in two disordered orientations in a 3:2 ratio, each involving C—Dâ‹ŻÏ€ to C 6 ring centers

    Developmental and Hormonal Regulation of Gibberellin Biosynthesis and Catabolism in Pea Fruit1[OA]

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    In pea (Pisum sativum), normal fruit growth requires the presence of the seeds. The coordination of growth between the seed and ovary tissues involves phytohormones; however, the specific mechanisms remain speculative. This study further explores the roles of the gibberellin (GA) biosynthesis and catabolism genes during pollination and fruit development and in seed and auxin regulation of pericarp growth. Pollination and fertilization events not only increase pericarp PsGA3ox1 message levels (codes for GA 3-oxidase that converts GA20 to bioactive GA1) but also reduce pericarp PsGA2ox1 mRNA levels (codes for GA 2-oxidase that mainly catabolizes GA20 to GA29), suggesting a concerted regulation to increase levels of bioactive GA1 following these events. 4-Chloroindole-3-acetic acid (4-Cl-IAA) was found to mimic the seeds in the stimulation of PsGA3ox1 and the repression of PsGA2ox1 mRNA levels as well as the stimulation of PsGA2ox2 mRNA levels (codes for GA 2-oxidase that mainly catabolizes GA1 to GA8) in pericarp at 2 to 3 d after anthesis, while the other endogenous pea auxin, IAA, did not. This GA gene expression profile suggests that both seeds and 4-Cl-IAA can stimulate the production, as well as modulate the half-life, of bioactive GA1, leading to initial fruit set and subsequent growth and development of the ovary. Consistent with these gene expression profiles, deseeded pericarps converted [14C]GA12 to [14C]GA1 only if treated with 4-Cl-IAA. These data further support the hypothesis that 4-Cl-IAA produced in the seeds is transported to the pericarp, where it differentially regulates the expression of pericarp GA biosynthesis and catabolism genes to modulate the level of bioactive GA1 required for initial fruit set and growth

    Tissue-Specific Regulation of Gibberellin Biosynthesis in Developing Pea Seeds1[W][OA]

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    Previous work suggests that gibberellins (GAs) play an important role in early seed development. To more fully understand the roles of GAs throughout seed development, tissue-specific transcription profiles of GA metabolism genes and quantitative profiles of key GAs were determined in pea (Pisum sativum) seeds during the seed-filling development period (8–20 d after anthesis [DAA]). These profiles were correlated with seed photoassimilate acquisition and storage as well as morphological development. Seed coat growth (8–12 DAA) and the subsequent dramatic expansion of branched parenchyma cells were correlated with both transcript abundance of GA biosynthesis genes and the concentration of the growth effector GA, GA1. These results suggest GA1 involvement in determining the rate of seed coat growth and sink strength. The endosperm’s PsGA20ox transcript abundance and the concentration of GA20 increased markedly as the endosperm reached its maximum volume (12 DAA), thus providing ample GA20 substrate for the GA 3-oxidases present in both the embryo and seed coat. Furthermore, PsGA3ox transcript profiles and trends in GA1 levels in embryos at 10 to 16 DAA and also in embryo axes at 18 DAA suggest localized GA1-induced growth in these tissues. A shift from synthesis of GA1 to that of GA8 occurred after 18 DAA in the embryo axis, suggesting that deactivation of GA1 to GA8 is a likely mechanism to limit embryo axis growth and allow embryo maturation to proceed. We hypothesize that GA biosynthesis and catabolism are tightly regulated to bring about the unique developmental events that occur during seed growth, development, and maturation

    C‑Shaped Diastereomers Containing Cofacial Thiophene-Substituted Quinoxaline Rings: Synthesis, Photophysical Properties, and X‑ray Crystallography

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    Synthesis and characterization of two diastereomeric C-shaped molecules containing cofacial thiophene-substituted quinoxaline rings are described. A previously known bis-α-diketone was condensed with an excess of 4-bromo-1,2-diaminobenzene in the presence of zinc acetate to give a mixture of two C-shaped diastereomers with cofacial bromine-substituted quinoxaline rings. After chromatographic separation, thiophene rings were installed by a microwave-assisted Suzuki coupling reaction, resulting in highly emissive diastereomeric compounds that were studied by UV–vis, fluorescence, and NMR spectroscopy, as well as X-ray crystallography. The unique symmetry of each diastereomer was confirmed by NMR spectroscopy. NMR data indicated that the <i>syn</i> isomer has restricted rotation about the bond connecting the thiophene and quinoxaline rings, which was also observed in the solid state. The spectroscopic properties of the C-shaped diastereomers were compared to a model compound containing only a single thiophene-substituted quinoxaline ring. Ground state intramolecular π–π interactions in solution were detected by NMR and UV–vis spectroscopy. Red-shifted emission bands, band broadening, and large Stokes shifts were observed, which collectively suggest excited state π–π interactions that produce excimer-like emissions, as well as a remarkable positive emission solvatochromism, indicating charge-transfer character in the excited state

    A seat-level nowcast of the Front National in the 2017 legislatives

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    We look to forecast the number of seats the Front National (FN) will win in the 2017 legislative election. We use the most recent subnational ballot, the 2015 regional election, to estimate support for the party, and model reallocation of first-round legislative votes in the second round by applying the pattern seen between the 2011 cantonal and 2012 legislative elections. Using different levels of turnout and four different scenarios of Left-bloc coalition arrangements, both of which strongly influence how the FN performs in run-off ballots, we estimate that a likely, but conservative, scenario would result in 29 FN seats, if a similar pattern to 2011–2012 obtains. This number of seats would allow the FN to form a Parliamentary group in the National Assembly

    Forecasting the FN presidential vote in the 2012 elections

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    Forecasting the Extreme Right vote in French elections is one of the few ‘third-party’ forecasts that has attracted attention in a forecasting literature focusing generally on incumbent performance and winners. Despite being a ‘hard case’ because of third-party status, unstable polling estimates and relatively few data points, previous models have provided relatively strong forecasts of the performance of the Front National (FN) and its erstwhile leader, Jean-Marie Le Pen. The recent succession of Le Pen by his daughter, Marine, and her apparent popularity pose a significant challenge to these models, however. In this article, we consider our previous model's prediction of her likely score in the first round of the presidentials, comparing this to standard forecasting benchmarks, and look at possible adjustments to account for the speculated ‘Marine effect’. We then compare this with other vote indicators including the results of an experimental expert judgment survey, finding that there is currently little evidence for a likely runaway success for the new FN leader in April 2012

    Ten-eleven translocation 1 (TET1) methylation is associated with childhood asthma and traffic-related air pollution

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    BackgroundAsthma is a complex disorder influenced by genetics and the environment. Recent findings have linked abnormal DNA methylation in T cells with asthma; however, the potential dysregulation of methylation in airway epithelial cells is unknown. Studies of mouse models of asthma have observed greater levels of 5-hydroxymethylcytosine (5-hmC) and ten-eleven translocation 1 (TET1) expression in lungs. TET proteins are known to catalyze methylation through modification of 5-methylcytosine to 5-hmC.ObjectiveWe sought to examine the association of TET1 methylation with asthma and traffic-related air pollution (TRAP).MethodsTET1 methylation levels from DNA derived from nasal airway epithelial cells collected from 12 African American children with physician-diagnosed asthma and their nonasthmatic siblings were measured by using Illumina 450K arrays. Regions of interest were verified by means of locus-specific pyrosequencing in 35 sibling pairs and replicated in an independent population (n = 186). Exposure to TRAP in participants' early life and at current home addresses was estimated by using a land-use regression model. Methylation studies in saliva, PBMCs, and human bronchial epithelial cells were done to support our findings.ResultsLoss of methylation at a single CpG site in the TET1 promoter (cg23602092) and increased global 5-hmC levels were significantly associated with asthma. In contrast, TRAP exposure at participants' current homes significantly increased methylation at the same site. Patterns were consistent across tissue sample types. 5-Aza-2'-deoxycytidine and diesel exhaust particle exposure in human bronchial epithelial cells was associated with altered TET1 methylation and expression and global 5-hmC levels.ConclusionsOur findings suggest a possible role of TET1 methylation in asthmatic patients and response to TRAP
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