Desorption of hot molecules from photon irradiated interstellar ices

We present experimental measurements of photodesorption from ices of astrophysical relevance. Layers of benzene and water ice were irradiated with a laser tuned to an electronic transition in the benzene molecule. The translational energy of desorbed molecules was measured by time-of-flight (ToF) mass spectrometry. Three distinct photodesorption processes were identified - a direct adsorbate-mediated desorption producing benzene molecules with a translational temperature of around 1200 K, an indirect adsorbate-mediated desorption resulting in water molecules with a translational temperature of around 450 K, and a substrate-mediated desorption of both benzene and water producing molecules with translational temperatures of around 530 K and 450 K respectively. The translational temperature of each population of desorbed molecules is well above the temperature of the ice matrix. The implications for gas-phase chemistry in the interstellar medium are discussed.Comment: 23 pages, including 4 figures; submitted to Ap

Brachypodium distachyon grain: identification and subcellular localization of storage proteins

Seed storage proteins are of great importance in nutrition and in industrial transformation because of their functional properties. Brachypodium distachyon has been proposed as a new model plant to study temperate cereals. The protein composition of Brachypodium grain was investigated by separating the proteins on the basis of their solubility combined with a proteomic approach. Salt-soluble proteins as well as salt-insoluble proteins separated by two-dimensional gel electrophoresis revealed 284 and 120 spots, respectively. Proteins from the major spots were sequenced by mass spectrometry and identified by searching against a Brachypodium putative protein database. Our analysis detected globulins and prolamins but no albumins. Globulins were represented mainly by the 11S type and their solubility properties corresponded to the glutelin found in rice. An in silico search for storage proteins returned more translated genes than expressed products identified by mass spectrometry, particularly in the case of prolamin type proteins, reflecting a strong expression of globulins at the expense of prolamins. Microscopic examination of endosperm cells revealed scarce small-size starch granules surrounded by protein bodies containing 11S globulins. The presence of protein bodies containing glutelins makes B. distachyon closer to rice or oat than to wheat endosperm

Antibiotic Transport in Resistant Bacteria: Synchrotron UV Fluorescence Microscopy to Determine Antibiotic Accumulation with Single Cell Resolution

A molecular definition of the mechanism conferring bacterial multidrug resistance is clinically crucial and today methods for quantitative determination of the uptake of antimicrobial agents with single cell resolution are missing. Using the naturally occurring fluorescence of antibacterial agents after deep ultraviolet (DUV) excitation, we developed a method to non-invasively monitor the quinolones uptake in single bacteria. Our approach is based on a DUV fluorescence microscope coupled to a synchrotron beamline providing tuneable excitation from 200 to 600 nm. A full spectrum was acquired at each pixel of the image, to study the DUV excited fluorescence emitted from quinolones within single bacteria. Measuring spectra allowed us to separate the antibiotic fluorescence from the autofluorescence contribution. By performing spectroscopic analysis, the quantification of the antibiotic signal was possible. To our knowledge, this is the first time that the intracellular accumulation of a clinical antibitiotic could be determined and discussed in relation with the level of drug susceptibility for a multiresistant strain. This method is especially important to follow the behavior of quinolone molecules at individual cell level, to quantify the intracellular concentration of the antibiotic and develop new strategies to combat the dissemination of MDR-bacteria. In addition, this original approach also indicates the heterogeneity of bacterial population when the same strain is under environmental stress like antibiotic attack

Autoantibodies against type I IFNs in patients with life-threatening COVID-19

Interindividual clinical variability in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is vast. We report that at least 101 of 987 patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia had neutralizing immunoglobulin G (IgG) autoantibodies (auto-Abs) against interferon-w (IFN-w) (13 patients), against the 13 types of IFN-a (36), or against both (52) at the onset of critical disease; a few also had auto-Abs against the other three type I IFNs. The auto-Abs neutralize the ability of the corresponding type I IFNs to block SARS-CoV-2 infection in vitro. These auto-Abs were not found in 663 individuals with asymptomatic or mild SARS-CoV-2 infection and were present in only 4 of 1227 healthy individuals. Patients with auto-Abs were aged 25 to 87 years and 95 of the 101 were men. A B cell autoimmune phenocopy of inborn errors of type I IFN immunity accounts for life-threatening COVID-19 pneumonia in at least 2.6% of women and 12.5% of men

Respiratory Infection Triggering Severe Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Georges Abi Abdallah,1 Sylvain Diop,2 Matthieu Jamme,3,4 Stéphane Legriel,1,5 Alexis Ferré1 1Intensive Care Unit, Versailles Hospital, Le Chesnay, France; 2Cardiothoracic Intensive Care Unit, Department of Anesthesiology, Marie Lannelongue Hospital, Le Plessis Robinson, France; 3Service de Réanimation Polyvalente, Hôpital Privé de l’Ouest Parisien, Ramsay-Générale de Santé, Trappes, France; 4CESP, INSERM U1018, Equipe Epidémiologie Clinique, Villejuif, France; 5University Paris-Saclay, UVSQ, INSERM, CESP, Team ”PsyDev”, Villejuif, FranceCorrespondence: Georges Abi Abdallah, Intensive Care Unit, Versailles Hospital, 177 Rue de Versailles, Le Chesnay, 78150, France, Email [email protected]: Data are scarce on respiratory infections during severe acute exacerbation of chronic obstructive pulmonary disease (COPD). This study aimed to investigate respiratory infection patterns in the intensive care unit (ICU) and identify variables associated with infection type and patient outcome.Methods: A retrospective, single-centre cohort study. All patients admitted (2015– 2021) to our ICU for severe acute exacerbation of COPD were included. Logistic multivariable regression analysis was performed to predict factors associated with infection and assess the association between infection and outcome.Results: We included 473 patients: 288 (60.9%) had respiratory infection and 139 (29.4%) required invasive mechanical ventilation. Eighty-nine (30.9%) had viral, 81 (28.1%) bacterial, 34 (11.8%) mixed, and 84 (29.2%) undocumented infections. Forty-seven (9.9%) patients died in the ICU and 67 (14.2%) in hospital. Factors associated with respiratory infection were temperature (odds ratio [+1°C]=1.43, P= 0.008) and blood neutrophils (1.07, P= 0.002). Male sex (2.21, P= 0.02) and blood neutrophils were associated with bacterial infection (1.06, P= 0.04). In a multivariable analysis, pneumonia (cause-specific hazard=1.75, P= 0.005), respiratory rate (1.17, P=0.04), arterial partial pressure of carbon-dioxide (1.08, P= 0.04), and lactate (1.14, P= 0.02) were associated with the need for invasive MV. Age (1.03, P= 0.03), immunodeficiency (1.96, P= 0.02), and altered performance status (1.78, P= 0.002) were associated with hospital mortality.Conclusions: Respiratory infections, 39.9% of which were bacterial, were the main cause of severe acute exacerbation of COPD. Body temperature and blood neutrophils were single markers of infection. Pneumonia was associated with the need for invasive mechanical ventilation but not with hospital mortality, as opposed to age, immunodeficiency, and altered performance status.Plain Language Summary: - This study investigates the prevalence, characteristics, and impact on outcomes of different types of respiratory infections triggering severe acute exacerbations of COPD.- Our retrospective cohort study of 473 critically ill patients found that respiratory infections, of which 39.9% were bacterial, were the main cause of severe exacerbation.- The type of infection (viral, bacterial, or mixt) was not associated with the need for invasive mechanical ventilation or mortality.- Early identification of the infectious agent is crucial for implementing effective therapy; however, the type of infection was not associated with the main outcomes.Keywords: pneumonia, infection, COPD, mechanical ventilation, mortalit

Ultraviolets for better diagnosis

International audienceBackgroundThe invention of the UV lamp by Dr Wood triggered the observation of fluorescence induced by UV from tissues and biological samples at the beginning of the last century with notably, the classification of the observable color from dissected tissues under UV excitation1. In the following years, it was widely used for tumors observation2. We would like to demonstrate that one century after, this method may be rejuvenated.Materials and methodsDISCO Beamline3 is a bending magnet beamline at synchrotron SOLEIL covering the unusual 1-21 eV energy range. One of its branches is dedicated to UV microscopic imaging of biological samples4.ResultsUse of deep ultraviolet (DUV, below 350 nm) fluorescence opens up new possibilities in biology because, it does not need external specific probes or labeling, but instead takes profit of the intrinsic fluorescence that arise from many biomolecules under deep ultraviolet excitation. Indeed, observation of label free biomolecules5 or active drugs6 ensures that the label will not modify the biolocalisation or any of its properties. UV monophotonic excitation does present real spectral excitation, leading the way to excitation imaging and a better selectivity of the chromophores. DUV excitation may also be used to track exogenous drugs or toxic compounds that present different spectral behaviour. Moreover, due to diffraction limit the lateral resolution is always increased when looking in the UV range allowing nanometric spatial resolution4. Examples of UV for diagnosis, in drug pharmacokinetic, in liver grafts quality and microcalcifications formations will be presented