Mitochondrial Genome Evolution and a Novel RNA Editing System in Deep-Branching Heteroloboseids

Discoba (Excavata) is an evolutionarily important group of eukaryotes that includes Jakobida, with the most bacterial-like mitochondrial genomes known, and Euglenozoa, many of which have extensively fragmented mitochondrial genomes. However, little is known about the mitochondrial genomes of Heterolobosea, the third main group of Discoba. Here, we studied two heteroloboseids—an undescribed amoeba “BB2” and Pharyngomonas kirbyi. Phylogenomic analysis revealed that they form a clade that is a sister group to all other Heterolobosea. We characterized the mitochondrial genomes of BB2 and P. kirbyi, which encoded 44 and 48 putative protein-coding genes respectively. Their gene contents were similar to that of Naegleria. In BB2, mitochondrially encoded RNAs were heavily edited, with ∼500 mononucleotide insertion events, mostly guanosines. These insertions always have the same identity as an adjacent nucleotide. Editing occurs in all ribosomal RNAs and protein-coding transcripts except one, and half of the transfer RNAs. Analysis of Illumina deep-sequencing data suggested that this RNA editing is very accurate and efficient, and most likely co-transcriptional. The dissimilarity of this editing process to other RNA editing phenomena in discobids, as well as its apparent absence in P. kirbyi, suggest that this remarkably extensive system of insertional editing evolved independently in the BB2 lineage, after its divergence from the P. kirbyi lineage

Observation of an Exotic Insulator to Insulator Transition upon Electron Doping the Mott Insulator CeMnAsO

Acknowledgements This research was supported by EPSRC (Grant no. EP/L002493/1 (A.C.M.)), The Carnegie Trust for the Universities of Scotland (PhD scholarship for S.S. (S.S.)) and the ILL (PhD studentship for G.B.L. (A.C.M.)). By the membership of the UK's HEC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202 (A.W.)), this work used the ARCHER2 UK National Supercomputing Service (http://www.archer2.ac.uk). We also acknowledge STFC-GB for provision of beamtime at the ILL.Peer reviewe

Search for Global Dipole Enhancements in the HiRes-I Monocular Data above 10^{18.5} eV

Several proposed source models for Ultra-High Energy Cosmic Rays (UHECRs) consist of dipole distributions oriented towards major astrophysical landmarks such as the galactic center, M87, or Centaurus A. We use a comparison between real data and simulated data to show that the HiRes-I monocular data for energies above 10^{18.5} eV is, in fact, consistent with an isotropic source model. We then explore methods to quantify our sensitivity to dipole source models oriented towards the Galactic Center, M87, and Centaurus A.Comment: 17 pages, 31 figure

Observation of the Ankle and Evidence for a High-Energy Break in the Cosmic Ray Spectrum

We have measured the cosmic ray spectrum at energies above $10^{17}$ eV using the two air fluorescence detectors of the High Resolution Fly's Eye experiment operating in monocular mode. We describe the detector, PMT and atmospheric calibrations, and the analysis techniques for the two detectors. We fit the spectrum to models describing galactic and extragalactic sources. Our measured spectrum gives an observation of a feature known as the ``ankle'' near $3\times 10^{18}$ eV, and strong evidence for a suppression near $6\times 10^{19}$ eV.Comment: 14 pages, 9 figures. To appear in Physics Letters B. Accepted versio

Efficacy of azithromycin in severe asthma from the AMAZES randomised trial

Background:Low-dose azithromycin is an effective therapy for persistent asthma; however, its benefit in severe asthma is not defined. Methods:Participants with severe asthma were identified from the AMAZES randomised, placebo-controlled trial of long-term (48 weeks) low-dose azithromycin. Participants who met one of the following severe asthma definitions were included: 1) Global Initiative for Asthma step 4 treatment with poor asthma control (asthma control questionnaire score ≥0.75); 2) International Severe Asthma Registry definition; 3) American Thoracic Society and European Respiratory Society severe asthma definitions. The rate of total exacerbations was calculated for each subgroup and efficacy of azithromycin compared with placebo. Asthma-related quality of life was assessed before and after treatment along with adverse effects. Results:Azithromycin significantly reduced asthma exacerbations in each group. In patients meeting the American Thoracic Society and European Respiratory Society task force definition of severe asthma (n=211), the rate of exacerbations with treatment was 1.2 per person-year, which was significantly less than for placebo (2.01 per person-year), giving an incidence rate ratio (95% CI) of 0.63 (0.41, 0.96). The proportion of participants experiencing at least one asthma exacerbation was reduced by azithromycin from 64% to 49% (p=0.021). A similar beneficial treatment effect was seen in participants poorly controlled with Global Initiative for Asthma step 4 treatment and those with International Severe Asthma Registry-defined severe asthma. Azithromycin also significantly improved the quality of life in severe asthma (p<0.05). Treatment was well tolerated, with gastrointestinal symptoms being the main adverse effect. Conclusion:Long-term, low-dose azithromycin reduced asthma exacerbations and improved the quality of life in patients with severe asthma, regardless of how this was defined. These data support the addition of azithromycin as a treatment option for patients with severe asthma.Peter G. Gibson, Ian A. Yang, John W. Upham, Paul N. Reynolds, Sandra Hodge, Alan L. James ... et al

Holocene El Niño–Southern Oscillation variability reflected in subtropical Australian precipitation

The La Niña and El Niño phases of the El Niño-Southern Oscillation (ENSO) have major impacts on regional rainfall patterns around the globe, with substantial environmental, societal and economic implications. Long-term perspectives on ENSO behaviour, under changing background conditions, are essential to anticipating how ENSO phases may respond under future climate scenarios. Here, we derive a 7700-year, quantitative precipitation record using carbon isotope ratios from a single species of leaf preserved in lake sediments from subtropical eastern Australia. We find a generally wet (more La Niña-like) mid-Holocene that shifted towards drier and more variable climates after 3200 cal. yr BP, primarily driven by increasing frequency and strength of the El Niño phase. Climate model simulations implicate a progressive orbitally-driven weakening of the Pacific Walker Circulation as contributing to this change. At centennial scales, high rainfall characterised the Little Ice Age (~1450–1850 CE) in subtropical eastern Australia, contrasting with oceanic proxies that suggest El Niño-like conditions prevail during this period. Our data provide a new western Pacific perspective on Holocene ENSO variability and highlight the need to address ENSO reconstruction with a geographically diverse network of sites to characterise how both ENSO, and its impacts, vary in a changing climate

Invertase, glucose oxidase and catalase for converting sucrose to fructose and gluconic acid through batch and membrane-continuous reactors

Conversion of sucrose into fructose and gluconic acid using invertase, glucose oxidase and catalase was studied by discontinuous (sequential or simultaneous addition of the enzymes) and continuous (simultaneous addition of the enzymes in a 100 kDa-ultrafiltration membrane reactor) processes. The following parameters were varied: concentration of enzymes, initial concentration of substrates (sucrose and glucose), pH, temperature and feeding rate (for continuous process). The highest yield of conversion (100%) was attained through the discontinuous (batch) process carried out at pH 4.5 and 37 ºC by the sequential addition of invertase (14.3 U), glucose oxidase (10,000 U) and catalase (59,000 U).Neste trabalho estudou-se a conversão da sacarose em frutose e ácido glicônico, usando as enzimas invertase, glicose oxidase e catalase, através do emprego de processo descontínuo (com adição sequencial ou simultânea das enzimas) e contínuo (adição simultânea das enzimas em reator com membrana acoplado à membrana de ultrafiltração de 100 kDa). Os parâmetros variados foram: a concentração das enzimas, a concentração inicial dos substratos (sacarose e glicose), o pH, a temperatura e a vazão específica de alimentação (processo contínuo). Obteve-se rendimento de 100%, quando a conversão foi conduzida por processo descontínuo em pH 4,5 e a 37 ºC com adição seqüencial das enzimas invertase (14,3 U), glicose oxidase (10.000 U) e catalase (59.000 U)