274 research outputs found

    Taxonomic and functional analyses of intact microbial communities thriving in extreme, astrobiology-relevant, anoxic sites

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMBackground: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to infer habitability of extraterrestrial settings. In contrast to Earth’s ecosystems, potential extraterrestrial biotopes are usually characterized by a lack of oxygen. Methods: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort. Results: The information retrieved from microbiome analyses on the intact microbial community thriving in the MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites compared to moderate environments. The microorganisms were characterized by an impressive machinery to withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant cosmopolitan group of 34 poly-extremophiles thriving in all sites. Conclusions: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental, terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living microorganisms in extreme environments with a high adaptation potential within habitability borders. Keywords: Extreme environments, Microbiomes, Archaea, Bacteria, Propidium monoazide, Astrobiology, Spaceanalogue, Extremophiles, Extraterrestrial life, Metagenomic

    Taxonomic and functional analyses of intact microbial communities thriving in extreme, astrobiology-relevant, anoxic sites

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    Background: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to infer habitability of extraterrestrial settings. In contrast to Earth’s ecosystems, potential extraterrestrial biotopes are usually characterized by a lack of oxygen. Methods: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort. Results: The information retrieved from microbiome analyses on the intact microbial community thriving in the MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites compared to moderate environments. The microorganisms were characterized by an impressive machinery to withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant cosmopolitan group of 34 poly-extremophiles thriving in all sites. Conclusions: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental, terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living microorganisms in extreme environments with a high adaptation potential within habitability borders

    Methionine supplementation for multi-organ dysfunction in MetRS-related pulmonary alveolar proteinosis

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    International audienceIntroduction Pulmonary alveolar proteinosis related to mutations in the methionine tRNA synthetase ( MARS1 ) gene is a severe, early-onset disease that results in death before the age of 2 years in one-third of patients. It is associated with a liver disease, growth failure and systemic inflammation. As methionine supplementation in yeast models restored normal enzymatic activity of the synthetase, we studied the tolerance, safety and efficacy of daily oral methionine supplementation in patients with severe and early disease. Methods Four patients received methionine supplementation and were followed for respiratory, hepatic, growth, and inflammation-related outcomes. Their course was compared to those of historical controls. Reactive oxygen species (ROS) production by patient monocytes before and after methionine supplementation was also studied. Results Methionine supplementation was associated with respiratory improvement, clearance of the extracellular lipoproteinaceous material, and discontinuation of whole-lung lavage in all patients. The three patients who required oxygen or non-invasive ventilation could be weaned off within 60 days. Liver dysfunction, inflammation, and growth delay also improved or resolved. At a cellular level, methionine supplementation normalised the production of reactive oxygen species by peripheral monocytes. Conclusion Methionine supplementation was associated with important improvements in children with pulmonary alveolar proteinosis related to mutations in the MARS1 gene. This study paves the way for similar strategies for other tRNA synthetase deficiencies

    Jet fragmentation transverse momentum distributions in pp and p-Pb collisions at s \sqrt{s} , sNN \sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    Jet fragmentation transverse momentum (jT_{T}) distributions are measured in proton-proton (pp) and proton-lead (p-Pb) collisions at sNN \sqrt{s_{\mathrm{NN}}} = 5.02 TeV with the ALICE experiment at the LHC. Jets are reconstructed with the ALICE tracking detectors and electromagnetic calorimeter using the anti-kT_{T} algorithm with resolution parameter R = 0.4 in the pseudorapidity range |η| < 0.25. The jT_{T} values are calculated for charged particles inside a fixed cone with a radius R = 0.4 around the reconstructed jet axis. The measured jT_{T} distributions are compared with a variety of parton-shower models. Herwig and Pythia 8 based models describe the data well for the higher jT_{T} region, while they underestimate the lower jT_{T} region. The jT_{T} distributions are further characterised by fitting them with a function composed of an inverse gamma function for higher jT_{T} values (called the “wide component”), related to the perturbative component of the fragmentation process, and with a Gaussian for lower jT_{T} values (called the “narrow component”), predominantly connected to the hadronisation process. The width of the Gaussian has only a weak dependence on jet transverse momentum, while that of the inverse gamma function increases with increasing jet transverse momentum. For the narrow component, the measured trends are successfully described by all models except for Herwig. For the wide component, Herwig and PYTHIA 8 based models slightly underestimate the data for the higher jet transverse momentum region. These measurements set constraints on models of jet fragmentation and hadronisation

    Production of charged pions, kaons, and (anti-)protons in Pb-Pb and inelastic pppp collisions at sNN\sqrt {s_{NN}} = 5.02 TeV

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    International audienceMid-rapidity production of π±\pi^{\pm}, K±\rm{K}^{\pm} and (pˉ\bar{\rm{p}})p measured by the ALICE experiment at the LHC, in Pb-Pb and inelastic pp collisions at sNN\sqrt{s_{\rm{NN}}} = 5.02 TeV, is presented. The invariant yields are measured over a wide transverse momentum (pTp_{\rm{T}}) range from hundreds of MeV/cc up to 20 GeV/cc. The results in Pb-Pb collisions are presented as a function of the collision centrality, in the range 0-90%. The comparison of the pTp_{\rm{T}}-integrated particle ratios, i.e. proton-to-pion (p/π\pi) and kaon-to-pion (K/π\pi) ratios, with similar measurements in Pb-Pb collisions at sNN\sqrt{s_{\rm{NN}}} = 2.76 TeV show no significant energy dependence. Blast-wave fits of the pTp_{\rm{T}} spectra indicate that in the most central collisions radial flow is slightly larger at 5.02 TeV with respect to 2.76 TeV. Particle ratios (p/π\pi, K/π\pi) as a function of pTp_{\rm{T}} show pronounced maxima at pTp_{\rm{T}} \approx 3 GeV/cc in central Pb-Pb collisions. At high pTp_{\rm{T}}, particle ratios at 5.02 TeV are similar to those measured in pp collisions at the same energy and in Pb-Pb collisions at sNN\sqrt{s_{\rm{NN}}} = 2.76 TeV. Using the pp reference spectra measured at the same collision energy of 5.02 TeV, the nuclear modification factors for the different particle species are derived. Within uncertainties, the nuclear modification factor is particle species independent for high pTp_{\rm{T}} and compatible with measurements at sNN\sqrt{s_{\rm{NN}}} = 2.76 TeV. The results are compared to state-of-the-art model calculations, which are found to describe the observed trends satisfactorily

    Measurements of the groomed and ungroomed jet angularities in pp collisions at s \sqrt{s} = 5.02 TeV

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    International audienceThe jet angularities are a class of jet substructure observables which characterize the angular and momentum distribution of particles within jets. These observables are sensitive to momentum scales ranging from perturbative hard scatterings to nonperturbative fragmentation into final-state hadrons. We report measurements of several groomed and ungroomed jet angularities in pp collisions at s \sqrt{s} = 5.02 TeV with the ALICE detector. Jets are reconstructed using charged particle tracks at midrapidity (|η| < 0.9). The anti-kT_{T} algorithm is used with jet resolution parameters R = 0.2 and R = 0.4 for several transverse momentum {p}_{\mathrm{T}}^{\mathrm{ch}} ^{jet} intervals in the 20–100 GeV/c range. Using the jet grooming algorithm Soft Drop, the sensitivity to softer, wide-angle processes, as well as the underlying event, can be reduced in a way which is well-controlled in theoretical calculations. We report the ungroomed jet angularities, λα_{α}, and groomed jet angularities, λα,g_{α,g}, to investigate the interplay between perturbative and nonperturbative effects at low jet momenta. Various angular exponent parameters α = 1, 1.5, 2, and 3 are used to systematically vary the sensitivity of the observable to collinear and soft radiation. Results are compared to analytical predictions at next-to-leading-logarithmic accuracy, which provide a generally good description of the data in the perturbative regime but exhibit discrepancies in the nonperturbative regime. Moreover, these measurements serve as a baseline for future ones in heavy-ion collisions by providing new insight into the interplay between perturbative and nonperturbative effects in the angular and momentum substructure of jets. They supply crucial guidance on the selection of jet resolution parameter, jet transverse momentum, and angular scaling variable for jet quenching studies.[graphic not available: see fulltext

    Neutron emission in ultraperipheral Pb-Pb collisions at sNN\sqrt {s_{NN}} = 5.02 TeV

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    In ultraperipheral collisions (UPCs) of relativistic nuclei without overlap of nuclear densities, the two nuclei are excited by the Lorentz-contracted Coulomb fields of their collision partners. In these UPCs, the typical nuclear excitation energy is below a few tens of MeV, and a small number of nucleons are emitted in electromagnetic dissociation (EMD) of primary nuclei, in contrast to complete nuclear fragmentation in hadronic interactions. The cross sections of emission of given numbers of neutrons in UPCs of 208^{208}Pb nuclei at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02~TeV were measured with the neutron zero degree calorimeters (ZDCs) of the ALICE detector at the LHC, exploiting a similar technique to that used in previous studies performed at sNN=2.76\sqrt{s_{\mathrm{NN}}}=2.76~TeV. In addition, the cross sections for the exclusive emission of 1, 2, 3, 4 and 5 forward neutrons in the EMD, not accompanied by the emission of forward protons, and thus mostly corresponding to the production of 207,206,205,204,203^{207,206,205,204,203}Pb, respectively, were measured for the first time. The predictions from the available models describe the measured cross sections well. These cross sections can be used for evaluating the impact of secondary nuclei on the LHC components, in particular, on superconducting magnets, and also provide useful input for the design of the Future Circular Collider (FCC-hh).In ultraperipheral collisions (UPCs) of relativistic nuclei without overlap of nuclear densities, the two nuclei are excited by the Lorentz-contracted Coulomb fields of their collision partners. In these UPCs, the typical nuclear excitation energy is below a few tens of MeV, and a small number of nucleons are emitted in electromagnetic dissociation (EMD) of primary nuclei, in contrast to complete nuclear fragmentation in hadronic interactions. The cross sections of emission of given numbers of neutrons in UPCs of Pb208 nuclei at sNN=5.02 TeV were measured with the neutron zero degree calorimeters (ZDCs) of the ALICE detector at the LHC, exploiting a similar technique to that used in previous studies performed at sNN=2.76 TeV. In addition, the cross sections for the exclusive emission of one, two, three, four, and five forward neutrons in the EMD, not accompanied by the emission of forward protons, and thus mostly corresponding to the production of Pb207,206,205,204,203, respectively, were measured for the first time. The predictions from the available models describe the measured cross sections well. These cross sections can be used for evaluating the impact of secondary nuclei on the LHC components, in particular, on superconducting magnets, and also provide useful input for the design of the Future Circular Collider (FCC-hh).In ultraperipheral collisions (UPCs) of relativistic nuclei without overlap of nuclear densities, the two nuclei are excited by the Lorentz-contracted Coulomb fields of their collision partners. In these UPCs, the typical nuclear excitation energy is below a few tens of MeV, and a small number of nucleons are emitted in electromagnetic dissociation (EMD) of primary nuclei, in contrast to complete nuclear fragmentation in hadronic interactions. The cross sections of emission of given numbers of neutrons in UPCs of 208^{208}Pb nuclei at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV were measured with the neutron zero degree calorimeters (ZDCs) of the ALICE detector at the LHC, exploiting a similar technique to that used in previous studies performed at sNN=2.76\sqrt{s_{\mathrm{NN}}}=2.76 TeV. In addition, the cross sections for the exclusive emission of one, two, three, four, and five forward neutrons in the EMD, not accompanied by the emission of forward protons, and thus mostly corresponding to the production of 207,206,205,204,203^{207,206,205,204,203}Pb, respectively, were measured for the first time. The predictions from the available models describe the measured cross sections well. These cross sections can be used for evaluating the impact of secondary nuclei on the LHC components, in particular, on superconducting magnets, and also provide useful input for the design of the Future Circular Collider (FCC-hh)

    Inclusive quarkonium production in pp collisions at s=5.02\sqrt{s} = 5.02 TeV

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    This article reports on the inclusive production cross section of several quarkonium states, J/ψ\mathrm{J}/\psi, ψ(2S)\psi {\rm (2S)}, Υ(1S)\Upsilon\rm(1S), Υ(2S)\Upsilon\rm(2S), and Υ(3S)\Upsilon\rm(3S), measured with the ALICE detector at the LHC, in \pp collisions at s=5.02\sqrt{s} = 5.02 TeV. The analysis is performed in the dimuon decay channel at forward rapidity (2.5<y<42.5 < y < 4). The measured cross sections, assuming unpolarized quarkonia, are: σJ/ψ=5.88±0.03±0.34 μ\sigma_{\mathrm{J}/\psi} = 5.88 \pm 0.03 \pm 0.34\ \mub, σψ(2S)=0.87±0.06±0.10 μ\sigma_{\psi {\rm (2S)}} = 0.87 \pm 0.06 \pm 0.10\ \mub, σΥ(1S)=45.5±3.9±3.5\sigma_{\Upsilon\rm(1S)} = 45.5 \pm 3.9 \pm 3.5 nb, σΥ(2S)=22.4±3.2±2.7\sigma_{\Upsilon\rm(2S)} = 22.4 \pm 3.2 \pm 2.7 nb, and σΥ(3S)=4.9±2.2±1.0\sigma_{\Upsilon\rm(3S)} = 4.9 \pm 2.2 \pm 1.0 nb, where the first (second) uncertainty is the statistical (systematic) one. The transverse-momentum (pTp_{\rm T}) and rapidity (yy) differential cross sections for J/ψ\mathrm{J}/\psi, ψ(2S)\psi {\rm (2S)}, Υ(1S)\Upsilon\rm(1S), and the ψ(2S)\psi {\rm (2S)}-to-J/ψ\mathrm{J}/\psi cross section ratios are presented. For the first time, the cross sections of the three Υ\Upsilon states, as well as the ψ(2S)\psi {\rm (2S)} one as a function of pTp_{\rm T} and yy, are measured at s=5.02\sqrt{s} = 5.02 TeV at forward rapidity. These measurements also significantly extend the J/ψ\mathrm{J}/\psipTp_{\rm T} reach with respect to previously published results. A comparison with ALICE measurements in pp collisions at s=2.76\sqrt{s} = 2.76, 7, 8, and 13 TeV is presented and the energy dependence of quarkonium production cross sections is discussed. Finally, the results are compared with the predictions from several production models

    Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at s\sqrt{s} = 13 TeV

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    The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity (y<0.5\left| y\right| < 0.5) are measured in proton-proton collisions at s\sqrt{s} = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of KS0\mathrm{K}^{0}_{S}, Λ\Lambda , Ξ\Xi , and Ω\Omega increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 TeV
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