209 research outputs found

    Microbial diversity of hydrothermal sediments in the Guaymas Basin: Evidence for anaerobic methanotrophic communities

    Get PDF
    Microbial communities in hydrothermally active sediments of the Guaymas Basin (Gulf of California, Mexico) were studied by using 16S rRNA sequencing and carbon isotopic analysis of archaeal and bacterial lipids. The Guaymas sediments harbored uncultured euryarchaeota of two distinct phylogenetic lineages within the anaerobic methane oxidation 1 (ANME-1) group, ANME-1a and ANME-1b, and of the ANME-2c lineage within the Methanosarcinales, both previously assigned to the methanotrophic archaea. The archaeal lipids in the Guaymas Basin sediments included archaeol, diagnostic for nonthermophilic euryarchaeota, and sn-2-hydroxyarchaeol, with the latter compound being particularly abundant in cultured members of the Methanosarcinales. The concentrations of these compounds were among the highest observed so far in studies of methane seep environments. The δ-13C values of these lipids (δ-13C = -89 to -58%) indicate an origin from anaerobic methanotrophic archaea. This molecular-isotopic signature was found not only in samples that yielded predominantly ANME-2 clones but also in samples that yielded exclusively ANME-1 clones. ANME-1 archaea therefore remain strong candidates for mediation of the anaerobic oxidation of methane. Based on 16S rRNA data, the Guaymas sediments harbor phylogenetically diverse bacterial populations, which show considerable overlap with bacterial populations of geothermal habitats and natural or anthropogenic hydrocarbon-rich sites. Consistent with earlier observations, our combined evidence from bacterial phylogeny and molecular-isotopic data indicates an important role of some novel deeply branching bacteria in anaerobic methanotrophy. Anaerobic methane oxidation likely represents a significant and widely occurring process in the trophic ecology of methane-rich hydrothermal vents, This study stresses a high diversity among communities capable of anaerobic oxidation of methane

    Identifying optimal doses of heart failure medications in men compared with women: a prospective, observational cohort study

    Get PDF
    Background: Guideline-recommended doses of angiotensin-converting-enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs), and β blockers are similar for men and women with heart failure with reduced ejection fraction (HFrEF), even though there are known sex differences in pharmacokinetics of these drugs. We hypothesised that there might be sex differences in the optimal dose of ACE inhibitors or ARBs and β blockers in patients with HFrEF. Methods: We did a post-hoc analysis of BIOSTAT-CHF, a prospective study in 11 European countries of patients with heart failure in whom initiation and up-titration of ACE inhibitors or ARBs and β blockers was encouraged by protocol. We included only patients with left ventricular ejection fraction less than 40%, and excluded those who died within the first 3 months. Primary outcome was a composite of time to all-cause mortality or hospitalisation for heart failure. Findings were validated in ASIAN-HF, an independent cohort of 3539 men and 961 women with HFrEF. Findings: Among 1308 men and 402 women with HFrEF from BIOSTAT-CHF, women were older (74 [12] years vs 70 [12] years, p<0·0001) and had lower bodyweights (72 [16] kg vs 85 [18] kg, p<0·0001) and heights (162 [7] cm vs 174 [8] cm, p<0·0001) than did men, although body-mass index did not differ significantly. A similar number of men and women reached guideline-recommended target doses of ACE inhibitors or ARBs (99 [25%] vs 304 [23%], p=0·61) and β blockers (57 [14%] vs 168 [13%], p=0·54). In men, the lowest hazards of death or hospitalisation for heart failure occurred at 100% of the recommended dose of ACE inhibitors or ARBs and β blockers, but women showed approximately 30% lower risk at only 50% of the recommended doses, with no further decrease in risk at higher dose levels. These sex differences were still present after adjusting for clinical covariates, including age and body surface area. In the ASIAN-HF registry, similar patterns were observed for both ACE inhibitors or ARBs and β blockers, with women having approximately 30% lower risk at 50% of the recommended doses, with no further benefit at higher dose levels. Interpretation: This study suggests that women with HFrEF might need lower doses of ACE inhibitors or ARBs and β blockers than men, and brings into question what the true optimal medical therapy is for women versus men

    Transitory Microbial Habitat in the Hyperarid Atacama Desert

    Get PDF
    Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: a physico-chemical characterization of the soil habitability after an exceptional rain event, identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today's extreme hyperaridity. [Abstract copyright: Copyright © 2018 the Author(s). Published by PNAS.

    XIST-promoter demethylation as tissue biomarker for testicular germ cell tumors and spermatogenesis quality

    Get PDF
    Background: The event of X chromosome inactivation induced by XIST, which is physiologically observed in females, is retained in testicular germ cell tumors (TGCTs), as a result of a supernumerary X chromosome constitution. X chromosome inactivation also occurs in male germline, specifically during spermatogenesis. We aimed to analyze the promoter methylation status of XIST in a series of TGCT tissues, representative cell lines, and testicular parenchyma. Methods: Two independent cohorts were included, comprising a total of 413 TGCT samples, four (T)GCT cell lines, and 86 testicular parenchyma samples. The relative amount of methylated and demethylated XIST promoter fragments was assessed by quantitative methylation-specific PCR (qMSP) and more sensitive high-resolution melting (HRM) methylation analyses. Results: Seminomas showed a lower amount of methylated XIST fragments as compared to non-seminomas or normal testis (p < 0.0001), allowing for a good discrimination among these groups (area under the curve 0.83 and 0.81, respectively). Seminomas showed a significantly higher content of demethylated XIST as compared to non-seminomas. The percentage of demethylated XIST fragment in cell lines reflected their chromosomal constitution (number of extra X chromosomes). A novel and strong positive correlation between the Johnsen’s score and XIST demethylation was identified (r = 0.75, p < 0.0001). Conclusions: The X chromosome inactivation event and demethylated XIST promoter are promising biomarkers for TGCTs and for assessing spermatogenesis quality

    Study protocol for the multicentre cohorts of Zika virus infection in pregnant women, infants, and acute clinical cases in Latin America and the Caribbean: The ZIKAlliance consortium

    Get PDF
    Background: The European Commission (EC) Horizon 2020 (H2020)-funded ZIKAlliance Consortium designed a multicentre study including pregnant women (PW), children (CH) and natural history (NH) cohorts. Clinical sites were selected over a wide geographic range within Latin America and the Caribbean, taking into account the dynamic course of the ZIKV epidemic. Methods: Recruitment to the PW cohort will take place in antenatal care clinics. PW will be enrolled regardless of symptoms and followed over the course of pregnancy, approximately every 4 weeks. PW will be revisited at delivery (or after miscarriage/abortion) to assess birth outcomes, including microcephaly and other congenital abnormalities according to the evolving definition of congenital Zika syndrome (CZS). After birth, children will be followed for 2 years in the CH cohort. Follow-up visits are scheduled at ages 1-3, 4-6, 12, and 24 months to assess neurocognitive and developmental milestones. In addition, a NH cohort for the characterization of symptomatic rash/fever illness was designed, including follow-up to capture persisting health problems. Blood, urine, and other biological materials will be collected, and tested for ZIKV and other relevant arboviral diseases (dengue, chikungunya, yellow fever) using RT-PCR or serological methods. A virtual, decentralized biobank will be created. Reciprocal clinical monitoring has been established between partner sites. Substudies of ZIKV seroprevalence, transmissio

    Track D Social Science, Human Rights and Political Science

    Full text link
    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

    Combination of searches for Higgs boson pairs in pp collisions at \sqrts = 13 TeV with the ATLAS detector

    Get PDF
    This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 &lt; kappa(lambda) &lt; 12.0 (-5.8 &lt; kappa(lambda) &lt; 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. For complete list of authors see http://dx.doi.org/10.1016/j.physletb.2019.135103</p

    Searches for lepton-flavour-violating decays of the Higgs boson in s=13\sqrt{s}=13 TeV pp\mathit{pp} collisions with the ATLAS detector

    Get PDF
    This Letter presents direct searches for lepton flavour violation in Higgs boson decays, H → eτ and H → μτ , performed with the ATLAS detector at the LHC. The searches are based on a data sample of proton–proton collisions at a centre-of-mass energy √s = 13 TeV, corresponding to an integrated luminosity of 36.1 fb−1. No significant excess is observed above the expected background from Standard Model processes. The observed (median expected) 95% confidence-level upper limits on the leptonflavour-violating branching ratios are 0.47% (0.34+0.13−0.10%) and 0.28% (0.37+0.14−0.10%) for H → eτ and H → μτ , respectively.publishedVersio

    Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb⁻¹ of pp collisions at \sqrts = 13 TeV with the ATLAS experiment

    Get PDF
    A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb−1 of proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tqγ coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tuγ coupling of 36 fb (78 fb) and on the branching ratio for t→γu of 2.8×10−5 (6.1×10−5). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tcγ coupling of 40 fb (33 fb) and on the branching ratio for t→γc of 22×10−5 (18×10−5). © 2019 The Author(s
    corecore