99 research outputs found
Total Synthesis of Amphidinolideโ F
Orchestrated yet nonconsonant: The challenge posed by the โumpoledโ 1,4-dioxygenation pattern characteristic for the polyketide frame of amphidinolideโ
F was mastered by a late-stage ring-closing alkyne metathesis followed by a directed transannular hydration under the aegis of a carbophilic ฯ-acid catalyst. This concordant strategy enabled a concise total synthesis of this enticing marine natural product
(HT)-Raman microscopy to study (U,Pu)O2 fuel microstructure illustration on (U,La)O2 and CeO2; first results on (U,Pu)O2
International audienc
Combined Bacteriophage and Antibiotic Treatment Prevents Pseudomonas aeruginosa Infection of Wild Type and cftr- Epithelial Cells.
With the increase of infections due to multidrug resistant bacterial pathogens and the shortage of antimicrobial molecules with novel targets, interest in bacteriophages as a therapeutic option has regained much attraction. Before the launch of future clinical trials, in vitro studies are required to better evaluate the efficacies and potential pitfalls of such therapies. Here we studied in an ex vivo human airway epithelial cell line model the efficacy of phage and ciprofloxacin alone and in combination to treat infection by Pseudomonas aeruginosa. The Calu-3 cell line and the isogenic CFTR knock down cell line (cftr-) infected apically with P. aeruginosa strain PAO1 showed a progressive reduction in transepithelial resistance during 24 h. Administration at 6 h p.i. of single phage, phage cocktails or ciprofloxacin alone prevented epithelial layer destruction at 24 h p.i. Bacterial regrowth, due to phage resistant mutants harboring mutations in LPS synthesis genes, occurred thereafter both in vitro and ex vivo. However, co-administration of two phages combined with ciprofloxacin efficiently prevented PAO1 regrowth and maintained epithelial cell integrity at 72 p.i. The phage/ciprofloxacin treatment did not induce an inflammatory response in the tested cell lines as determined by nanoString <sup>ยฎ</sup> gene expression analysis. We conclude that combination of phage and ciprofloxacin efficiently protects wild type and cftr- epithelial cells from infection by P. aeruginosa and emergence of phage resistant mutants without inducing an inflammatory response. Hence, phage-antibiotic combination should be a safe and promising anti-Pseudomonas therapy for future clinical trials potentially including cystic fibrosis patients
Identification of Antigenic Proteins from Lichtheimia corymbifera for Farmer's Lung Disease Diagnosis.
The use of recombinant antigens has been shown to improve both the sensitivity and the standardization of the serological diagnosis of Farmer's lung disease (FLD). The aim of this study was to complete the panel of recombinant antigens available for FLD serodiagnosis with antigens of Lichtheimia corymbifera, known to be involved in FLD. L. corymbifera proteins were thus separated by 2D electrophoresis and subjected to western blotting with sera from 7 patients with FLD and 9 healthy exposed controls (HEC). FLD-associated immunoreactive proteins were identified by mass spectrometry based on a protein database specifically created for this study and subsequently produced as recombinant antigens. The ability of recombinant antigens to discriminate patients with FLD from controls was assessed by ELISA performed with sera from FLD patients (n = 41) and controls (n = 43) recruited from five university hospital pneumology departments of France and Switzerland. Forty-one FLD-associated immunoreactive proteins from L. corymbifera were identified. Six of them were produced as recombinant antigens. With a sensitivity and specificity of 81.4 and 77.3% respectively, dihydrolipoyl dehydrogenase was the most effective antigen for discriminating FLD patients from HEC. ELISA performed with the putative proteasome subunit alpha type as an antigen was especially specific (88.6%) and could thus be used for FLD confirmation. The production of recombinant antigens from L. corymbifera represents an additional step towards the development of a standardized ELISA kit for FLD diagnosis
Human cryptosporidiosis in immunodeficient patients in France (2015-2017)
Cryptosporidiosis is a common disease in children and immunodeficient individuals. In 2006, a national network was set up on the surveillance of human cryptosporidiosis in France. Since January 2015, the 41 tertiary care hospitals and the 3 private laboratories of the French National Network on the surveillance of human cryptosporidiosis have been able to declare confirmed cases of cryptosporidiosis online. Between 2015 and 2017, 210 cases of cryptosporidiosis were declared in immunodeficient patients in France; Cryptosporidium parvum and Cryptosporidium hominis represented 66% and 22% of cases, respectively. A peak was observed in autumn. Cryptosporidiosis occurred mainly in a context of solid organ transplantation (SOT) (49%) and of HIV infection (30%). In SOT recipients, cryptosporidiosis appeared more frequently in the first 6 months post transplantation. Regarding cases declared in SOT recipients, mycophenolate mofetil was used in 68%. A mortality rate of 6% was observed. Present results underline the importance of screening for cryptosporidiosis in immunocompromised patients suffering from diarrhea, especially in the course of major cell mediated immunodeficiency or even systematic screening before SOT. Exclusive Cryptosporidium free water feeding could be suggested during major cell mediated immunodeficiency
Stacking sequences for extensionally isotropic, fully isotropic and quasi-homogeneous orthotropic laminates
Stacking sequence listings are presented for fully uncoupled Extensionally
Isotropic (EILs), Fully Isotropic (FILs) and Quasi-Homogeneous Orthotropic
(QHOLs) angle-ply Laminates, with up to 21 plies. All are sub-sets of a
definitive list of Fully Orthotropic Laminates (FOLs), containing generally
non-symmetric stacking sequences that are characterized in terms of angle-
and cross-ply sub-sequence symmetries. Dimensionless parameters are given
for each stacking sequence, from which the ABD matrix is readily derived.
Expressions relating these dimensionless parameters to the well-known
lamination parameters are also given, together with graphical
representations of the feasible domains for Pi/3 and Pi/4 EILs and angle-ply
QHOLs containing two and three ply orientations. The feasible domain for
Pi/3 FILs is represented graphically by a single point, whereas the domain
for angle-ply QHOLs containing four ply orientations is represented by a
single stacking sequence
Optimization of radial diffusion coefficients for the proton radiation belt during the CRRES era
Proton flux measurements from the Proton Telescope instrument aboard the CRRES satellite are revisited, and used to drive a radial diffusion model of the inner proton belt at 1.1 โค L โค 1.65. Our model utilises a physicsโbased evaluation of the cosmic ray albedo neutron decay (CRAND) source, and coulomb collisional loss is driven by a drift averaged density model combining results from the International Reference Ionosphere, NRLMSISโ00 atmosphere and Radio Plasma Imager plasmasphere models, parameterised by solar activity and season. We drive our model using timeโaveraged data at L = 1.65 to calculate steady state profiles of equatorial phase space density, and optimise our choice of radial diffusion coefficients based on four defining parameters to minimise the difference between model and data. This is first performed for a quiet period when the belt can be assumed to represent steady state. Additionally, we investigate fitting steady state solutions to time averages taken during active periods where the data exhibits limited deviation from steady state, demonstrated by CRRES measurements following the 24th March 1991 storm. We also discuss a way to make the optimisation process more reliable by excluding periods of variability in plasmaspheric density from any time average. Lastly, we compare our resultant diffusion coefficients to those derived via a similar process in previous work, and diffusion coefficients derived for electrons from ground and in situ observations. We find that higher diffusion coefficients are derived compared with previous work, and suggest more work is required to derive proton diffusion coefficients for different geomagnetic activity levels
Metabolic engineering of astaxanthin biosynthesis in maize endosperm and characterization of a prototype high oil hybrid
Maize was genetically engineered for the biosynthesis of the high value carotenoid astaxanthin in the kernel endosperm. Introduction of a ฮฒ-carotene hydroxylase and a ฮฒ-carotene ketolase into a white maize genetic background extended the carotenoid pathway to astaxanthin. Simultaneously, phytoene synthase, the controlling enzyme of carotenogenesis, was over-expressed for enhanced carotenoid production and lycopene ฮต-cyclase was knocked-down to direct more precursors into the ฮฒ-branch of the extended ketocarotenoid pathway which ends with astaxanthin. This astaxanthin-accumulating transgenic line was crossed into a high oil- maize genotype in order to increase the storage capacity for lipophilic astaxanthin. The high oil astaxanthin hybrid was compared to its astaxanthin producing parent. We report an in depth metabolomic and proteomic analysis which revealed major up- or down- regulation of genes involved in primary metabolism. Specifically, amino acid biosynthesis and the citric acid cycle which compete with the synthesis or utilization of pyruvate and glyceraldehyde 3-phosphate, the precursors for carotenogenesis, were down-regulated. Nevertheless, principal component analysis demonstrated that this compositional change is within the range of the two wild type parents used to generate the high oil producing astaxanthin hybrid
Microorganisms
The indoor microbial community is a mixture of microorganisms resulting from outdoor ecosystems that seed the built environment. However, the biogeography of the indoor microbial community is still inadequately studied. Dust from more than 3000 dwellings across France was analyzed by qPCR using 17 targets: 10 molds, 3 bacteria groups, and 4 mites. Thus, the first spatial description of the main indoor microbial allergens on the French territory, in relation with biogeographical factors influencing the distribution of microorganisms, was realized in this study. Ten microorganisms out of 17 exhibited increasing abundance profiles across the country: Five microorganisms (Dermatophagoรฏdes pteronyssinus, Dermatophagoรฏdes spp., Streptomyces spp., Cladosporium sphaerospermum, Epicoccum nigrum) from northeast to southwest, two (Cryptococcus spp., Alternaria alternata) from northwest to southeast, Mycobacteria from east to west, Aspergillus fumigatus from south to north, and Penicillium chrysogenum from south to northeast. These geographical patterns were partly linked to climate and land cover. Multivariate analysis showed that composition of communities seemed to depend on landscapes, with species related to closed and rather cold and humid landscapes (forests, located in the northeast) and others to more open, hot, and dry landscapes (herbaceous and coastal regions, located in the west). This study highlights the importance of geographical location and outdoor factors that shape communities. In order to study the effect of microorganisms on human health (allergic diseases in particular), it is important to identify biogeographic factors that structure microbial communities on large spatial scales and to quantify the exposure with quantitative tools, such as the multi-qPCR approach
Rapid diagnostic tests relying on antigen detection from stool as an efficient point of care testing strategy for giardiasis and cryptosporidiosis? Evaluation of a new immunochromatographic duplex assay
Microscopy is the gold standard for the diagnosis of gastrointestinal parasites but is time-consuming and dependent on operator skills. Rapid diagnostic tests represent alternative methods but most evaluations have been conducted on a limited number of samples preventing their implementation in the clinical setting. We evaluated a new CE-IVD marked immunochromatographic assay (Crypto/Giardia K-SeTยฎ, Coris Bioconcept) for the detection of G. intestinalis and Cryptosporidium spp. in 2 phases (retrospective and prospective) on a set of 482 stool samples including rare Cryptosporidium species. Besides G. intestinalis, this test could represent a rapid and reliable alternative to the modified Ziehl-Neelsen staining for the diagnosis of cryptosporidiosis (sensitivity/specificity were 89.2%/99.3% and 86.7%/100% for G. intestinalis and Cryptosporidium resp.), reducing diagnostic delays. Such strategy would also be time-saving by avoiding wet mount microscopy and concentrations steps, being particularly appropriate for laboratories having little expertise in microscopy or not able to implement molecular diagnostic methods
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