43 research outputs found

    Fe\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e Precipitation in Magnetotactic Bacteria

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    Using Mössbauer resonance spectroscopy of 57Fe, we have determined the nature and distribution of major iron compounds in the magnetotactic bacterium Aquaspirillum magnetotacticum. In addition to magnetite (Fe3O4), cells contained a low-density hydrous ferric oxide, a high-density hydrous ferric oxide (ferrihydrite), and ferrous iron. Analysis at different temperatures of whole cells harvested early and late in growth, of mutant cells unable to synthesize magnetite, and of cell fractions enriched in 57Fe indicated that Fe3O4 precipitation resulted from partial reduction of the high-density hydrous ferric oxide precursor

    Robust Inference of Monocot Deep Phylogeny Using an Expanded Multigene Plastid Data Set

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    We use multiple photosynthetic, chlororespiratory, and plastid translation apparatus loci and their associated noncoding regions (ca. 16 kb per taxon, prior to alignment) to make strongly supported inferences of the deep internal branches of monocot phylogeny. Most monocot relationships are robust (an average of ca. 91 % bootstrap support per branch examined), including those poorly supported or unresolved in other studies. Our data strongly support a sister-group relationship between Asparagales and the commelinid monocots, the inclusion of the orchids in Asparagales, and the status of Petrosaviaceae as the sister group of all monocots except Acorus and Alismatales. The latter finding supports recognition of the order Petrosaviales. Also strongly supported is a placement of Petermannia disjunct from Colchicaceae (Liliales) and a sister-group relationship between Commelinales and Zingiberales. We highlight the remaining weak areas of monocot phylogeny, including the positions of Dioscoreales, Liliales, and Pandanales. Despite substantial variation in the overall rate of molecular evolution among lineages, inferred amounts of change among codon-position data partitions are correlated with each other across the monocot tree, consistent with low incongruence between these partitions. Ceratophyllum and Chloranthaceae appear to have a destabilizing effect on the position of the monocots among other angiosperms; the issue of monocot placement in broader angiosperm phylogeny remains problematic

    A High-Resolution SNP Array-Based Linkage Map Anchors a New Domestic Cat Draft Genome Assembly and Provides Detailed Patterns of Recombination

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    High-resolution genetic and physical maps are invaluable tools for building accurate genome assemblies, and interpreting results of genome-wide association studies (GWAS). Previous genetic and physical maps anchored good quality draft assemblies of the domestic cat genome, enabling the discovery of numerous genes underlying hereditary disease and phenotypes of interest to the biomedical science and breeding communities. However, these maps lacked sufficient marker density to order thousands of shorter scaffolds in earlier assemblies, which instead relied heavily on comparative mapping with related species. A high-resolution map would aid in validating and ordering chromosome scaffolds from existing and new genome assemblies. Here, we describe a high-resolution genetic linkage map of the domestic cat genome based on genotyping 453 domestic cats from several multi-generational pedigrees on the Illumina 63K SNP array. The final maps include 58,055 SNP markers placed relative to 6637 markers with unique positions, distributed across all autosomes and the X chromosome. Our final sex-averaged maps span a total autosomal length of 4464 cM, the longest described linkage map for any mammal, confirming length estimates from a previous microsatellite-based map. The linkage map was used to order and orient the scaffolds from a substantially more contiguous domestic cat genome assembly (Felis catusv8.0), which incorporated ∼20 × coverage of Illumina fragment reads. The new genome assembly shows substantial improvements in contiguity, with a nearly fourfold increase in N50 scaffold size to 18 Mb. We use this map to report probable structural errors in previous maps and assemblies, and to describe features of the recombination landscape, including a massive (∼50 Mb) recombination desert (of virtually zero recombination) on the X chromosome that parallels a similar desert on the porcine X chromosome in both size and physical location

    Abatacept, Cenicriviroc, or Infliximab for Treatment of Adults Hospitalized With COVID-19 Pneumonia: A Randomized Clinical Trial

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    IMPORTANCE: Immune dysregulation contributes to poorer outcomes in COVID-19. OBJECTIVE: To investigate whether abatacept, cenicriviroc, or infliximab provides benefit when added to standard care for COVID-19 pneumonia. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-masked, placebo-controlled clinical trial using a master protocol to investigate immunomodulators added to standard care for treatment of participants hospitalized with COVID-19 pneumonia. The results of 3 substudies are reported from 95 hospitals at 85 clinical research sites in the US and Latin America. Hospitalized patients 18 years or older with confirmed SARS-CoV-2 infection within 14 days and evidence of pulmonary involvement underwent randomization between October 2020 and December 2021. INTERVENTIONS: Single infusion of abatacept (10 mg/kg; maximum dose, 1000 mg) or infliximab (5 mg/kg) or a 28-day oral course of cenicriviroc (300-mg loading dose followed by 150 mg twice per day). MAIN OUTCOMES AND MEASURES: The primary outcome was time to recovery by day 28 evaluated using an 8-point ordinal scale (higher scores indicate better health). Recovery was defined as the first day the participant scored at least 6 on the ordinal scale. RESULTS: Of the 1971 participants randomized across the 3 substudies, the mean (SD) age was 54.8 (14.6) years and 1218 (61.8%) were men. The primary end point of time to recovery from COVID-19 pneumonia was not significantly different for abatacept (recovery rate ratio [RRR], 1.12 [95% CI, 0.98-1.28]; P = .09), cenicriviroc (RRR, 1.01 [95% CI, 0.86-1.18]; P = .94), or infliximab (RRR, 1.12 [95% CI, 0.99-1.28]; P = .08) compared with placebo. All-cause 28-day mortality was 11.0% for abatacept vs 15.1% for placebo (odds ratio [OR], 0.62 [95% CI, 0.41-0.94]), 13.8% for cenicriviroc vs 11.9% for placebo (OR, 1.18 [95% CI 0.72-1.94]), and 10.1% for infliximab vs 14.5% for placebo (OR, 0.59 [95% CI, 0.39-0.90]). Safety outcomes were comparable between active treatment and placebo, including secondary infections, in all 3 substudies. CONCLUSIONS AND RELEVANCE: Time to recovery from COVID-19 pneumonia among hospitalized participants was not significantly different for abatacept, cenicriviroc, or infliximab vs placebo. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04593940

    Global Carbon Budget 2022

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    Accurate assessment of anthropogenic carbon dioxide (CO2_2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodologies to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2_2 emissions (EFOS_{FOS}) are based on energy statistics and cement production data, while emissions from land-use change (ELUC_{LUC}), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2_2 concentration is measured directly, and its growth rate (GATM_{ATM}) is computed from the annual changes in concentration. The ocean CO2_2 sink (SOCEAN_{OCEAN}) is estimated with global ocean biogeochemistry models and observation-based data products. The terrestrial CO2_2 sink (SLAND_{LAND}) is estimated with dynamic global vegetation models. The resulting carbon budget imbalance (BIM_{IM}), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the year 2021, EFOS_{FOS} increased by 5.1 % relative to 2020, with fossil emissions at 10.1 ± 0.5 GtC yr1^{−1} (9.9 ± 0.5 GtC yr1^{−1} when the cement carbonation sink is included), and ELUC_{LUC} was 1.1 ± 0.7 GtC yr1^{−1}, for a total anthropogenic CO2_2 emission (including the cement carbonation sink) of 10.9 ± 0.8 GtC yr1^{−1} (40.0 ± 2.9 GtCO2_2). Also, for 2021, GATM_{ATM} was 5.2 ± 0.2 GtC yr1^{−1} (2.5 ± 0.1 ppm yr1^{−1}), SOCEAN_{OCEAN} was 2.9  ± 0.4 GtC yr1^{−1}, and SLAND_{LAND} was 3.5 ± 0.9 GtC yr1^{−1}, with a BIM_{IM} of −0.6 GtC yr1^{−1} (i.e. the total estimated sources were too low or sinks were too high). The global atmospheric CO2_2 concentration averaged over 2021 reached 414.71 ± 0.1 ppm. Preliminary data for 2022 suggest an increase in EFOS_{FOS} relative to 2021 of +1.0 % (0.1 % to 1.9 %) globally and atmospheric CO2_2 concentration reaching 417.2 ppm, more than 50 % above pre-industrial levels (around 278 ppm). Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2021, but discrepancies of up to 1 GtC yr1^{−1} persist for the representation of annual to semi-decadal variability in CO2_2 fluxes. Comparison of estimates from multiple approaches and observations shows (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) a low agreement between the different methods on the magnitude of the land CO2_2 flux in the northern extratropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set. The data presented in this work are available at https://doi.org/10.18160/GCP-2022 (Friedlingstein et al., 2022b)

    Search for pair production of excited top quarks in the lepton+jets final state

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