Disruption of Botryococcus braunii colonies by glycoside hydrolases

International audienceMicroalgae are a promising alternative resource to fossil-based products. Botryococcus braunii is a colonial green microalga having the ability to convert CO2 by photosynthesis into long chain hydrocarbons. These are excreted and trapped in an extracellular matrix (ECM). A panel of glycosidases ranging from arabinanase, galactananase to endoglucanase was tested for their ability to lyse the polysaccharides maintaining the B. braunii colony integrity in order to release the hydrocarbons present in the extracellular matrix without harming the cells. The BpGH9 endoglucanase from Bacillus pumilus was fused with CtCBM3a from Clostridium thermocellum and yellow fluorescent protein to probe the presence of microcrystalline cellulose in the cell wall of B. braunii and to increase the efficacy of the endoglucanase. All the tested enzymes were able to some extent to dissociate the cells from the extracellular matrix while keeping them alive, suggesting the feasibility of a semi-continuous in situ recovery of hydrocarbons

Vallée de l'Eure : une rivière, des territoires: Projet collectif de recherche. Rapport d'opérations 2019

Le PCR « Vallée de l’Eure : une rivière, des territoires » s’intéresse au bassin versant de l’Eure, sous bassin du Bassin parisien, encore très peu étudié sur le plan archéologique et historique. Il se place dans la continuité des grands programmes lancés à partir des années 1990 sur l’étude des dynamiques de peuplement et de l’organisation spatiale des territoires, qui ne cessent de se multiplier pour développer des problématiques autour du rôle des sociétés dans les phénomènes de transmission et de changement des formes spatiales, y intégrant aussi bien des études sur la morphologie des paysages que sur la formation des groupes culturels, jusqu’à la reconstitution de dynamiques socio-environnementales qu’engendrent au court du temps les interactions entre l’homme et son milieu, entre les sous-systèmes culturel et naturel.Le projet résulte d’une réflexion sur les réelles capacités documentaires d’un corpus donné en matière de reconstitution évolutive des paysages aussi bien naturels qu’anthropiques et sur les moyens à mettre en œuvre en termes d’efficacité et de pertinence pour pallier la discontinuité et le fractionnement de la donnée toutes périodes et disciplines confondues. En s’inscrivant volontairement dans un contexte de faible documentation archéologique, le projet ouvre sur une approche exploratoire et prospective, aussi bien sur le plan scientifique que technologique.Au-delà de l’enrichissement du corpus somme toute maigre des gisements archéologiques du secteur, il vise à restituer les modalités de la construction des territoires et des patrimoines naturels, culturels et sociaux sur le temps long en privilégiant le dialogue transchronologique et l’interdisciplinarité. Il met également en place une plateforme Web-SIG originale dont l’objectif est non seulement de centraliser la collecte des données pluridisciplinaires de manière à pouvoir les croiser, mais aussi, en amont comme en aval, à aider à la réflexion et à la décision sur le terrainen matière de connaissance, de conservation et a fortiori d’aménagement et de gestion des risques de notre environnement historique et naturel, passé, actuel et futur

Mycophenolic Acid Pharmacokinetics and Relapse in Children with Steroid–Dependent Idiopathic Nephrotic Syndrome

International audienceBACKGROUND AND OBJECTIVES:Therapeutic drug monitoring of mycophenolic acid can improve clinical outcome in organ transplantation and lupus, but data are scarce in idiopathic nephrotic syndrome. The aim of our study was to investigate whether mycophenolic acid pharmacokinetics are associated with disease control in children receiving mycophenolate mofetil for the treatment of steroid-dependent nephrotic syndrome.DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS:This was a retrospective multicenter study including 95 children with steroid-dependent nephrotic syndrome treated with mycophenolate mofetil with or without steroids. Area under the concentration-time curve of mycophenolic acid was determined in all children on the basis of sampling times at 20, 60, and 180 minutes postdose, using Bayesian estimation. The association between a threshold value of the area under the concentration-time curve of mycophenolic acid and the relapse rate was assessed using a negative binomial model.RESULTS:In total, 140 areas under the concentration-time curve of mycophenolic acid were analyzed. The findings indicate individual dose adaptation in 53 patients (38%) to achieve an area under the concentration-time curve target of 30-60 mg·h/L. In a multivariable negative binomial model including sex, age at disease onset, time to start of mycophenolate mofetil, previous immunomodulatory treatment, and concomitant prednisone dose, a level of area under the concentration-time curve of mycophenolic acid >45 mg·h/L was significantly associated with a lower relapse rate (rate ratio, 0.65; 95% confidence interval, 0.46 to 0.89; P=0.01).CONCLUSIONS:Therapeutic drug monitoring leading to individualized dosing may improve the efficacy of mycophenolate mofetil in steroid-dependent nephrotic syndrome. Additional prospective studies are warranted to determine the optimal target for area under the concentration-time curve of mycophenolic acid in this population

A Consensus Statement on SARS-CoV-2 Aerosol Dynamics

This statement aims to clarify the discussion surrounding a recent preprint(https://www.medrxiv.org/content/10.1101/2022.01.08.22268944v1) describing the aerosol dynamics of SARS-CoV-2 (the virus that causes COVID-19) which generated controversy in mainstream and social media and among infection prevention and control specialists. The study by Oswin et al. is complex and, as such, easily misinterpreted. It must be understood in the context provided by studies of human aerosol emission rates and viral loads in exhaled breath of infected persons, air movement and aerosol transport indoors, previous studies of airborne survival, and epidemiologic studies and outbreak investigations

A Consensus Statement on SARS-CoV-2 Aerosol Dynamics

A consensus statement from physicians and scientists with a range of expertise in the areas of respiratory infection and aerosols, to clarify the discussion surrounding a recent preprint (https://www.medrxiv.org/content/10.1101/2022.01.08.22268944v1) describing the aerosol dynamics of SARS-CoV-2 (the virus that causes COVID-19) which generated controversy in mainstream and social media and among infection prevention and control specialists. The study by Oswin et al. is complex and, as such, easily misinterpreted. It must be understood in the context provided by studies of human aerosol emission rates and viral loads in exhaled breath of infected persons, air movement and aerosol transport indoors, previous studies of airborne survival, and epidemiologic studies and outbreak investigations

Clearance of defective muscle stem cells by senolytics restores myogenesis in myotonic dystrophy type 1

Abstract Muscle stem cells, the engine of muscle repair, are affected in myotonic dystrophy type 1 (DM1); however, the underlying molecular mechanism and the impact on the disease severity are still elusive. Here, we show using patients’ samples that muscle stem cells/myoblasts exhibit signs of cellular senescence in vitro and in situ. Single cell RNAseq uncovers a subset of senescent myoblasts expressing high levels of genes related to the senescence-associated secretory phenotype (SASP). We show that the levels of interleukin-6, a prominent SASP cytokine, in the serum of DM1 patients correlate with muscle weakness and functional capacity limitations. Drug screening revealed that the senolytic BCL-XL inhibitor (A1155463) can specifically remove senescent DM1 myoblasts by inducing their apoptosis. Clearance of senescent cells reduced the expression of SASP, which rescued the proliferation and differentiation capacity of DM1 myoblasts in vitro and enhanced their engraftment following transplantation in vivo. Altogether, this study identifies the pathogenic mechanism associated with muscle stem cell defects in DM1 and opens a therapeutic avenue that targets these defective cells to restore myogenesis

COVID-19 indoor airborne transmission risk estimation based on practical risk indicators or CO2 level

Almost all COVID-19 superspreading events occur indoors, and are thought to be dominated by aerosol inhalation (“airborne transmission”). We model indoor SARS-CoV-2-containing aerosol concentration by analyzing its source (exhalation by infectors) and sinks in an indoor box modeling framework, and estimate exposure and infection risk of susceptible people through shared room airborne transmission based on the Wells-Riley model. We find that virus-containing aerosol generation rate, breathing flow rate, masking and its quality, ventilation and air cleaning rates, number of occupants, and duration of exposure all play some role in infection risk. The first 2 factors, related to activity type, are of particular importance. High physical intensity and/or vocalization level of the activity strongly increase infection risk. We propose two simple parameters that combine these key factors as indicators of infection risk. COVID-19 outbreaks show a clear trend in relation to these parameters that is consistent with an airborne infection model, supporting the importance of airborne transmission for these outbreaks. The observed trends of outbreak size vs. risk parameters allow us to recommend values of the parameters to minimize COVID-19 indoor infection risk. All of the pre-pandemic spaces are in a regime where they are highly sensitive to mitigation efforts

Erratum: Practical Indicators for Risk of Airborne Transmission in Shared Indoor Environments and Their Application to COVID-19 Outbreaks (Environmental Science and Technology (2022) 56:2 (1125-1137) DOI: 10.1021/acs.est.1c06531)

We have identified an error on some of the calculations shown in Table 2c of the paper. This is only significant for a few cells on the bottom right corner (dark red) and it reduces the risk of infection at those locations. However, it does not change the numerical or color trends on the table, and those locations continue to have the highest risk. The error does not affect anything else on the paper or any of the conclusions.</p