32 research outputs found
Natural environments, ancestral diets, and microbial ecology: is there a modern âpaleo-deficit disorderâ? Part II
Microarray analysis and scale-free gene networks identify candidate regulators in drought-stressed roots of loblolly pine (P. taeda L.)
<p>Abstract</p> <p>Background</p> <p>Global transcriptional analysis of loblolly pine (<it>Pinus taeda </it>L.) is challenging due to limited molecular tools. PtGen2, a 26,496 feature cDNA microarray, was fabricated and used to assess drought-induced gene expression in loblolly pine propagule roots. Statistical analysis of differential expression and weighted gene correlation network analysis were used to identify drought-responsive genes and further characterize the molecular basis of drought tolerance in loblolly pine.</p> <p>Results</p> <p>Microarrays were used to interrogate root cDNA populations obtained from 12 genotype à treatment combinations (four genotypes, three watering regimes). Comparison of drought-stressed roots with roots from the control treatment identified 2445 genes displaying at least a 1.5-fold expression difference (false discovery rate = 0.01). Genes commonly associated with drought response in pine and other plant species, as well as a number of abiotic and biotic stress-related genes, were up-regulated in drought-stressed roots. Only 76 genes were identified as differentially expressed in drought-recovered roots, indicating that the transcript population can return to the pre-drought state within 48 hours. Gene correlation analysis predicts a scale-free network topology and identifies eleven co-expression modules that ranged in size from 34 to 938 members. Network topological parameters identified a number of central nodes (hubs) including those with significant homology (E-values †2 à 10<sup>-30</sup>) to 9-cis-epoxycarotenoid dioxygenase, zeatin O-glucosyltransferase, and ABA-responsive protein. Identified hubs also include genes that have been associated previously with osmotic stress, phytohormones, enzymes that detoxify reactive oxygen species, and several genes of unknown function.</p> <p>Conclusion</p> <p>PtGen2 was used to evaluate transcriptome responses in loblolly pine and was leveraged to identify 2445 differentially expressed genes responding to severe drought stress in roots. Many of the genes identified are known to be up-regulated in response to osmotic stress in pine and other plant species and encode proteins involved in both signal transduction and stress tolerance. Gene expression levels returned to control values within a 48-hour recovery period in all but 76 transcripts. Correlation network analysis indicates a scale-free network topology for the pine root transcriptome and identifies central nodes that may serve as drivers of drought-responsive transcriptome dynamics in the roots of loblolly pine.</p
Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs
Life-threatening `breakthrough' cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS- CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals ( age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto- Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-a2 and IFN-., while two neutralized IFN-omega only. No patient neutralized IFN-ss. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60â109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
âTypicalâ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (â€â18 years: 69, 48, 23; 85%), older adults (â„â70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each Pâ<â0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
DĂ©termination des paramĂštres contrĂŽlant lâagglomĂ©ration de poussiĂšres de Mn pour amĂ©liorer la prĂ©dictibilitĂ© des procĂ©dĂ©s
The mining and metallurgical industries produce significant amount of fine materials (<3mm) each year, which bears a high economic and ecological impact. Recycling these materials through cold, binder-free agglomeration is the best course of action, but still lacks predictability. The present study aims increases this predictability through a deeper comprehension of the phenomena. An extensive characterization of the chemical, physical and morphological characteristics of the fine materials generated along the ferromanganese alloy production process was performed. A qualitative prediction of the agglomeration potential of the material was developed based on theoretical and empirical comparisons. Agglomeration experiments using uniaxial compaction were performed on bentonite, kaolinite, enriched ore and hausmannite samples to test the hypothesis formulated. They confirmed the importance of the presence of materials with a layered structure (such as clays) and/or that deform plastically. The moisture addition and the pressure increase have an upper limit of efficiency, depending on the material. Preliminary DEM modelling were performed to assess the impact of the variation of youngâs modulus, bond strength and bond size on the simulation of the agglomerate strength and breakage style.Les poussiĂšres (<3 mm) gĂ©nĂ©rĂ©es chaque annĂ©e par les industries miniĂšres et mĂ©tallurgiques ont un impact Ă©conomique et Ă©cologique consĂ©quent. Le recyclage de ces matĂ©riaux par lâagglomĂ©ration Ă froid et sans liant est la meilleure option, mais ces procĂ©dĂ©s manquent de prĂ©dictibilitĂ©. La prĂ©sente Ă©tude vise Ă amĂ©liorer cette prĂ©dictibilitĂ© grĂące Ă une meilleure comprĂ©hension des phĂ©nomĂšnes.Une caractĂ©risation Ă©tendue des propriĂ©tĂ©s chimiques, physiques et morphologiques a Ă©tĂ© rĂ©alisĂ©e sur les matĂ©riaux fins gĂ©nĂ©rĂ© durant la production dâalliages de ferromanganĂšse. Une prĂ©diction qualitative a pu ĂȘtre dĂ©veloppĂ©e selon des considĂ©rations thĂ©oriques et empiriques. Des tests de compaction uniaxiale ont Ă©tĂ© rĂ©alisĂ©s sur des Ă©chantillons de bentonite, kaolinite, minerai enrichi et hausmannite pour tester les hypothĂšses formulĂ©es. Ils ont confirmĂ© lâimportance de la prĂ©sence de matĂ©riaux en feuillet et/ou qui se dĂ©forment de façon plastique. Lâajout dâhumiditĂ© et lâaccroissement de la pression ont une limite maximale dâefficacitĂ©, dĂ©pendante du matĂ©riau. Des tests de modĂ©lisation DEM prĂ©liminaires ont Ă©tĂ© rĂ©alisĂ©s pour estimer lâimpact des variation du module dâYoung et de la force et la taille des liens sur la force des agglomĂ©rĂ©s et leur comportement Ă la cassure
Binder-free tableting experiments on manganese oxides and industrial mineral powders
International audienceCold, binder-free tableting experiments under controlled pressure (0-450 MPa), water addition (0-10 wt.%) and pH (4, 11) were performed on powder of pyrolusite ore concentrates, refined hausmannite, bentonite, kaolinite, as well as blends of those materials. It has been shown that increased pressure was beneficial for agglomeration of oxide materials, but pressure > 250 MPa triggered an elastic recovery in the clay minerals. Water addition up to 4 wt.% improved tabletability, increasing diametral resistance and reducing elastic recovery and fines generation. Amounts above 6 wt.% decreased diametral resistance. The presence of layered-structure minerals (such as montmorillonite, kaolinite, lithiophorite) appeared to be key to determine the agglomeration potential of a sample. This study also showed that tableting provides good performances for recycling industrial manganese oxide fines by obtaining industrial-grade resistance for tablets made with an 80/20 pyrolusite concentrate/hausmannite blends and 4 wt.% H2O