301 research outputs found

    Evidence for different binding sites on the 33-kDa protein for DCMU, atrazine and QB

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    AbstractTwo DCMU-resistant strains of the cyanobacterium Synechocystis 6714 were used to analyse the binding sites of DCMU, atrazine and QB. DCMUr-IIA was DCMU and atrazine resistant; it presented an impaired electron flow and its 33-kDa protein was weakly attached to the membrane. DCMUr-IIB, derived from the former, simultaneously regained atrazine sensitivity, normal electron flow and a tight linkage of the 33-kDa protein to the membrane. This mutant shows that loss of DCMU binding does not necessarily affect the binding of either atrazine or QB. The role of the 33-kDa protein is discussed

    Étude comparative de la mesure de l'épaisseur du buffy-coat avec les valeurs chiffrées de l'hémogramme chez le chien

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    Le buffy coat, obtenu après centrifugation de sang de chien recueilli sur anticoagulant selon les recommandations du National Committee for Clinical Laboratory Standards (NCCLS), est le reflet de la numération leuco-plaquettaire chez le chien. Notre étude s’intéresse à la fiabilité de la mesure de cette couche leuco-plaquettaire en vue d’un diagnostic rapide de leucopénie et leucocytose. Seules des méthodes de mesures simples (abaque, réglette et papier millimétré) ont été étudiées dans un souci de réalisation au quotidien par le praticien vétérinaire. Notre étude comparative montre que la mesure du leucocrite est un outil diagnostic supplémentaire dans le cas de leucocytoses marquées

    Double-walled carbon nanotubes trigger IL-1β release in human monocytes through Nlrp3 inflammasome activation

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    Because of their outstanding physical properties, carbon nanotubes (CNTs) are promising new materials in the field of nanotechnology. It is therefore imperative to assess their adverse effects on human health. Monocytes/macrophages that recognize and eliminate the inert particles constitute the main target of CNTs. In this article, we report our finding that double-walled CNTs (DWCNTs) synergize with Tolllike receptor agonists to enhance IL-1β release in human monocytes. We show that DWCNTs–induced IL-1β secretion is exclusively linked to caspase-1 and to Nlrp3 inflammasome activation in human monocytes. We also establish that this activation requires DWCNTs phagocytosis and potassium efflux, but not reactive oxygen specied (ROS) generation. Moreover, inhibition of lysosomal acidification or cathepsin-B activation reduces DWCNT-induced IL-1β secretion, suggesting that Nlrp3 inflammasome activation occurs via lysosomal destabilization. Thus, DWCNTs present a health hazard due to their capacity to activate Nlrp3 inflammasome, recalling the inflammation caused by asbestos and hence demonstrating that they should be used with caution. From the Clinical Editor: This is a very important biosafety/toxicity study regarding double walled carbon nanotubes. The investigators demonstrate that such nanotubes do represent a health hazard due to their capacity to activate Nlrp3 inflammasome, resembling the inflammation caused by asbestos. While further study of this phenomenon is definitely needed, the above findings clearly suggest that special precautions need to be taken when applying these nanoparticles in human disease research

    Small-scale gene duplications played a major role in the recent evolution of wheat chromosome 3B

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    Background: Bread wheat is not only an important crop, but its large (17 Gb), highly repetitive, and hexaploid genome makes it a good model to study the organization and evolution of complex genomes. Recently, we produced a high quality reference sequence of wheat chromosome 3B (774 Mb), which provides an excellent opportunity to study the evolutionary dynamics of a large and polyploid genome, specifically the impact of single gene duplications.Results: We find that 27 % of the 3B predicted genes are non-syntenic with the orthologous chromosomes of Brachypodium distachyon, Oryza sativa, and Sorghum bicolor, whereas, by applying the same criteria, non-syntenic genes represent on average only 10 % of the predicted genes in these three model grasses. These non-syntenic genes on 3B have high sequence similarity to at least one other gene in the wheat genome, indicating that hexaploid wheat has undergone massive small-scale interchromosomal gene duplications compared to other grasses. Insertions of non-syntenic genes occurred at a similar rate along the chromosome, but these genes tend to be retained at a higher frequency in the distal, recombinogenic regions. The ratio of non-synonymous to synonymous substitution rates showed a more relaxed selection pressure for non-syntenic genes compared to syntenic genes, and gene ontology analysis indicated that non-syntenic genes may be enriched in functions involved in disease resistance.Conclusion: Our results highlight the major impact of single gene duplications on the wheat gene complement and confirm the accelerated evolution of the Triticeae lineage among grasses

    Covichem: A biochemical severity risk score of COVID-19 upon hospital admission

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    Clinical and laboratory predictors of COVID-19 severity are now well described and combined to propose mortality or severity scores. However, they all necessitate saturable equipment such as scanners, or procedures difficult to implement such as blood gas measures. To provide an easy and fast COVID-19 severity risk score upon hospital admission, and keeping in mind the above limits, we sought for a scoring system needing limited invasive data such as a simple blood test and co-morbidity assessment by anamnesis. A retrospective study of 303 patients (203 from Bordeaux University hospital and an external independent cohort of 100 patients from Paris Pitié-Salpêtrière hospital) collected clinical and biochemical parameters at admission. Using stepwise model selection by Akaike Information Criterion (AIC), we built the severity score Covichem. Among 26 tested variables, 7: obesity, cardiovascular conditions, plasma sodium, albumin, ferritin, LDH and CK were the independent predictors of severity used in Covichem (accuracy 0.87, AUROC 0.91). Accuracy was 0.92 in the external validation cohort (89% sensitivity and 95% specificity). Covichem score could be useful as a rapid, costless and easy to implement severity assessment tool during acute COVID-19 pandemic waves
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