133 research outputs found

    A-to-I RNA editing in the earliest-diverging Eumetazoan phyla

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Molecular Biology and Evolution 34 (2017): 1890-1901, doi:10.1093/molbev/msx125.The highly conserved ADAR enzymes, found in all multicellular metazoans, catalyze the editing of mRNA transcripts by the deamination of adenosines to inosines. This type of editing has two general outcomes: site specific editing, which frequently leads to recoding, and clustered editing, which is usually found in transcribed genomic repeats. Here, for the first time, we looked for both editing of isolated sites and clustered, non-specific sites in a basal metazoan, the coral Acropora millepora during spawning event, in order to reveal its editing pattern. We found that the coral editome resembles the mammalian one: it contains more than 500,000 sites, virtually all of which are clustered in non-coding regions that are enriched for predicted dsRNA structures. RNA editing levels were increased during spawning and increased further still in newly released gametes. This may suggest that editing plays a role in introducing variability in coral gametes.This work was supported by the Australian Research Council (to PK), the European Research Council (grant 311257), the I-CORE Program of the Planning and Budgeting Committee in Israel (grants 41/11 and 1796/12), and the Israel Science Foundation (1380/14)

    Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands

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    Coordination complexes that possess large magnetic anisotropy (otherwise known as zero-field splitting, ZFS) have possible applications in the field of magnetic materials, including single molecule magnets (SMMs). Previous studies have explored the role of coordination number and geometry in controlling the magnetic anisotropy and SMM behavior of high-spin (S = 3/2) Co(II) complexes. Building upon these efforts, the present work examines the impact of ligand oxidation state and structural distortions on the spin states and ZFS parameters of pentacoordinate Co(II) complexes. The five complexes included in this study (1–5) have the general formula, [Co(TpPh2)(LX,Y)]n+ (X = O, S; Y = N, O; n = 0 or 1), where TpPh2 is the scorpionate ligand hydrotris(3,5-diphenyl-pyrazolyl)borate(1−) and LX,Y are bidentate dioxolene-type ligands that can access multiple oxidation states. The specific LX,Y ligands used herein are 4,6-di-tert-butyl substituted o-aminophenolate and o-aminothiophenolate (1 and 2, respectively), o-iminosemiquinonate and o-semiquinonate radicals (3 and 4, respectively), and o-iminobenzoquinone (5). Each complex exhibits a distorted trigonal bipyramidal geometry, as revealed by single-crystal X-ray diffraction. Direct current (dc) magnetic susceptibility experiments confirmed that the complexes with closed-shell ligands (1, 2, and 5) possess S = 3/2 ground states with negative D-values (easy-axis anisotropy) of −41, −78, and −30 cm–1, respectively. For 3 and 4, antiferromagnetic coupling between the Co(II) center and o-(imino)semiquinonate radical ligand results in S = 1 ground states that likewise exhibit very large and negative anisotropy (−100 \u3e D \u3e −140 cm–1). Notably, ZFS was measured directly for each complex using far-infrared magnetic spectroscopy (FIRMS). In combination with high-frequency and -field electron paramagnetic resonance (HFEPR) studies, these techniques provided precise spin-Hamiltonian parameters for complexes 1, 2, and 5. Multireference ab initio calculations, using the CASSCF/NEVPT2 approach, indicate that the strongly negative anisotropies of these Co(II) complexes arise primarily from distortions in the equatorial plane due to constrictions imposed by the TpPh2 ligand. This effect is further amplified by cobalt(II)-radical exchange interactions in 3 and 4

    Effect of Theophylline as Adjunct to Inhaled Corticosteroids on Exacerbations in Patients With COPD: A Randomized Clinical Trial

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    Importance: Chronic obstructive pulmonary disease (COPD) is a major global health issue and theophylline is used extensively. Preclinical investigations have demonstrated that low plasma concentrations (1-5 mg/L) of theophylline enhance antiinflammatory effects of corticosteroids in COPD.  Objective: To investigate the effectiveness of adding low-dose theophylline to inhaled corticosteroids in COPD.  Design, Setting, and Participants: The TWICS (theophylline with inhaled corticosteroids) trial was a pragmatic, double-blind, placebo-controlled, randomized clinical trial that enrolled patients with COPD between February 6, 2014, and August 31, 2016. Final follow-up ended on August 31, 2017. Participants had a ratio of forced expiratory volume in the first second to forced vital capacity (FEV1/FVC) of less than 0.7 with at least 2 exacerbations (treated with antibiotics, oral corticosteroids, or both) in the previous year and were using an inhaled corticosteroid. This study included 1578 participants in 121 UK primary and secondary care sites.  Interventions: Participants were randomized to receive low-dose theophylline (200 mg once or twice per day) to provide plasma concentrations of 1 to 5 mg/L (determined by ideal body weight and smoking status) (n = 791) or placebo (n = 787).  Main Outcomes and Measures: The number of participant-reported moderate or severe exacerbations treated with antibiotics, oral corticosteroids, or both over the 1-year treatment period.  Results: Of the 1567 participants analyzed, mean (SD) age was 68.4 (8.4) years and 54% (843) were men. Data for evaluation of the primary outcome were available for 1536 participants (98%) (772 in the theophylline group; 764 in the placebo group). In total, there were 3430 exacerbations: 1727 in the theophylline group (mean, 2.24 [95% CI, 2.10-2.38] exacerbations per year) vs 1703 in the placebo group (mean, 2.23 [95% CI, 2.09-2.37] exacerbations per year); unadjusted mean difference, 0.01 (95% CI, −0.19 to 0.21) and adjusted incidence rate ratio, 0.99 (95% CI, 0.91-1.08). Serious adverse events in the theophylline and placebo groups included cardiac, 2.4% vs 3.4%; gastrointestinal, 2.7% vs 1.3%; and adverse reactions such as nausea (10.9% vs 7.9%) and headaches (9.0% vs 7.9%).  Conclusions and Relevance: Among adults with COPD at high risk of exacerbation treated with inhaled corticosteroids, the addition of low-dose theophylline, compared with placebo, did not reduce the number COPD exacerbations over a 1-year period. The findings do not support the use of low-dose theophylline as adjunctive therapy to inhaled corticosteroids for the prevention of COPD exacerbations

    Low-dose oral theophylline combined with inhaled corticosteroids for people with chronic obstructive pulmonary disease and high risk of exacerbations: a RCT

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    BACKGROUND: Despite widespread use of therapies such as inhaled corticosteroids (ICSs), people with chronic obstructive pulmonary disease (COPD) continue to suffer, have reduced life expectancy and utilise considerable NHS resources. Laboratory investigations have demonstrated that at low plasma concentrations (1-5 mg/l) theophylline markedly enhances the anti-inflammatory effects of corticosteroids in COPD. OBJECTIVE: To determine the clinical effectiveness and cost-effectiveness of adding low-dose theophylline to a drug regimen containing ICSs in people with COPD at high risk of exacerbation. DESIGN: A multicentre, pragmatic, double-blind, randomised, placebo-controlled clinical trial. SETTING: The trial was conducted in 121 UK primary and secondary care sites. PARTICIPANTS: People with COPD [i.e. who have a forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) of < 0.7] currently on a drug regimen including ICSs with a history of two or more exacerbations treated with antibiotics and/or oral corticosteroids (OCSs) in the previous year. INTERVENTIONS: Participants were randomised (1 : 1) to receive either low-dose theophylline or placebo for 1 year. The dose of theophylline (200 mg once or twice a day) was determined by ideal body weight and smoking status. PRIMARY OUTCOME: The number of participant-reported exacerbations in the 1-year treatment period that were treated with antibiotics and/or OCSs. RESULTS: A total of 1578 people were randomised (60% from primary care): 791 to theophylline and 787 to placebo. There were 11 post-randomisation exclusions. Trial medication was prescribed to 1567 participants: 788 in the theophylline arm and 779 in the placebo arm. Participants in the trial arms were well balanced in terms of characteristics. The mean age was 68.4 [standard deviation (SD) 8.4] years, 54% were male, 32% smoked and mean FEV1 was 51.7% (SD 20.0%) predicted. Primary outcome data were available for 98% of participants: 772 in the theophylline arm and 764 in the placebo arm. There were 1489 person-years of follow-up data. The mean number of exacerbations was 2.24 (SD 1.99) for participants allocated to theophylline and 2.23 (SD 1.97) for participants allocated to placebo [adjusted incidence rate ratio (IRR) 0.99, 95% confidence interval (CI) 0.91 to 1.08]. Low-dose theophylline had no significant effects on lung function (i.e. FEV1), incidence of pneumonia, mortality, breathlessness or measures of quality of life or disease impact. Hospital admissions due to COPD exacerbation were less frequent with low-dose theophylline (adjusted IRR 0.72, 95% CI 0.55 to 0.94). However, 39 of the 51 excess hospital admissions in the placebo group were accounted for by 10 participants having three or more exacerbations. There were no differences in the reporting of theophylline side effects between the theophylline and placebo arms. LIMITATIONS: A higher than expected percentage of participants (26%) ceased trial medication; this was balanced between the theophylline and placebo arms and mitigated by over-recruitment (n = 154 additional participants were recruited) and the high rate of follow-up. The limitation of not using documented exacerbations is addressed by evidence that patient recall is highly reliable and the results of a small within-trial validation study. CONCLUSION: For people with COPD at high risk of exacerbation, the addition of low-dose oral theophylline to a drug regimen that includes ICSs confers no overall clinical or health economic benefit. This result was evident from the intention-to-treat and per-protocol analyses. FUTURE WORK: To promote consideration of the findings of this trial in national and international COPD guidelines. TRIAL REGISTRATION: Current Controlled Trials ISRCTN27066620. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 37. See the NIHR Journals Library website for further project information

    Major Cellular and Physiological Impacts of Ocean Acidification on a Reef Building Coral

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    As atmospheric levels of CO2 increase, reef-building corals are under greater stress from both increased sea surface temperatures and declining sea water pH. To date, most studies have focused on either coral bleaching due to warming oceans or declining calcification due to decreasing oceanic carbonate ion concentrations. Here, through the use of physiology measurements and cDNA microarrays, we show that changes in pH and ocean chemistry consistent with two scenarios put forward by the Intergovernmental Panel on Climate Change (IPCC) drive major changes in gene expression, respiration, photosynthesis and symbiosis of the coral, Acropora millepora, before affects on biomineralisation are apparent at the phenotype level. Under high CO2 conditions corals at the phenotype level lost over half their Symbiodinium populations, and had a decrease in both photosynthesis and respiration. Changes in gene expression were consistent with metabolic suppression, an increase in oxidative stress, apoptosis and symbiont loss. Other expression patterns demonstrate upregulation of membrane transporters, as well as the regulation of genes involved in membrane cytoskeletal interactions and cytoskeletal remodeling. These widespread changes in gene expression emphasize the need to expand future studies of ocean acidification to include a wider spectrum of cellular processes, many of which may occur before impacts on calcification

    Contrasting Light Spectra Constrain the Macro and Microstructures of Scleractinian Corals

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    The morphological plasticity of scleractinian corals can be influenced by numerous factors in their natural environment. However, it is difficult to identify in situ the relative influence of a single biotic or abiotic factor, due to potential interactions between them. Light is considered as a major factor affecting coral skeleton morphology, due to their symbiotic relation with photosynthetic zooxanthellae. Nonetheless, most studies addressing the importance of light on coral morphological plasticity have focused on photosynthetically active radiation (PAR) intensity, with the effect of light spectra remaining largely unknown. The present study evaluated how different light spectra affect the skeleton macro- and microstructures in two coral species (Acropora formosa sensu Veron (2000) and Stylophora pistillata) maintained under controlled laboratory conditions. We tested the effect of three light treatments with the same PAR but with a distinct spectral emission: 1) T5 fluorescent lamps with blue emission; 2) Light Emitting Diodes (LED) with predominantly blue emission; and 3) Light Emitting Plasma (LEP) with full spectra emission. To exclude potential bias generated by genetic variability, the experiment was performed with clonal fragments for both species. After 6 months of experiment, it was possible to detect in coral fragments of both species exposed to different light spectra significant differences in morphometry (e.g., distance among corallites, corallite diameter, and theca thickness), as well as in the organization of their skeleton microstructure. The variability found in the skeleton macro- and microstructures of clonal organisms points to the potential pitfalls associated with the exclusive use of morphometry on coral taxonomy. Moreover, the identification of a single factor influencing the morphology of coral skeletons is relevant for coral aquaculture and can allow the optimization of reef restoration efforts

    Influence of a motovibrators setting angle on the amplitude of vibrations of open grid plates of a seed grader

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    Niniejsza praca dotyczy przesiewacza wibracyjnego do nasion. Autorzy opracowania zajmują się przesiewaczami napędzanymi dwoma symetrycznymi, zsynchronizowanymi motowibratorami rotacyjnymi. Napęd ten jest stosunkowo prosty i pozwala na osiągnięcie dobrych właściwości procesowych maszyny przesiewającej. Badania tego przesiewacza są wykonywane z użyciem Systemu PULSE firmy Brüel&Kjar. Celem pracy było zbadanie amplitudy drgań poszczególnych pokładów sitowych, przy różnych ustawieniach motowibratorów bocznych w stosunku do osi pionowej przesiewacza wibracyjnego do nasion. Badania amplitudy drgań na poszczególnych pokładach sitowych dały pogląd o ruchu sit przesiewacza.The work herein concerns a seed grader. The authors of the study are occupied with seed graders which are powered by two symmetric, synchronised rotational motovibrators. This drive is quite simple and allows for obtaining good process properties of the screen. Research on this screen are carried out with the use of PULSE System by Brüel&Kjar. The purpose of the work was to examine the amplitude of vibrations of particular open grid plates at different settings of side motovibrators compared to a vertical axis of a seed grader. Research on the amplitude of vibrations on particular open grid plates gave some information on the movement of sieves of the seed grader

    Resistances of air flow through a conical drier filled with bean seeds

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    W pracy przeprowadzono badania oporu przepływu powietrza przez złoże nasion fasoli w części stożkowej suszarki. Starano się znaleźć zależności spadku ciśnienia na złożu nasion fasoli od prędkości przepływającego powietrza w suszarce stożkowej. Do opisu szukanej zależności posłużono się równaniem Erguna. Otrzymane wyniki podstawiono także do równania Leva, celem wyznaczenia współczynnika oporu nasion fasoli dla przepływającego powietrza.In this work, tests of the resistance of air flow through a bean seed deposit in the conical part of the drier were carried out. Attempts were made to find the relationship between the drop of pressure on the bean seed deposit and the speed of flowing air in the conical drier. For the description of the relationship being sought, the Ergun equation was used. The received results were also substituted for the Leva equation in order to determine the bean seed resistance coefficient for the flowing air
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