182 research outputs found

    Strigolactone biosynthesis and signaling in plant development.

    Get PDF
    Strigolactones (SLs), first identified for their role in parasitic and symbiotic interactions in the rhizosphere, constitute the most recently discovered group of plant hormones. They are best known for their role in shoot branching but, more recently, roles for SLs in other aspects of plant development have emerged. In the last five years, insights into the SL biosynthetic pathway have also been revealed and several key components of the SL signaling pathway have been identified. Here, and in the accompanying poster, we summarize our current understanding of the SL pathway and discuss how this pathway regulates plant development

    Escherichia coli α-Hemolysin Counteracts the Anti-Virulence Innate Immune Response Triggered by the Rho GTPase Activating Toxin CNF1 during Bacteremia

    Get PDF
    International audienceThe detection of the activities of pathogen-encoded virulence factors by the innate immune system has emerged as a new paradigm of pathogen recognition. Much remains to be determined with regard to the molecular and cellular components contributing to this defense mechanism in mammals and importance during infection. Here, we reveal the central role of the IL-1 beta signaling axis and Gr1+ cells in controlling the Escherichia coli burden in the blood in response to the sensing of the Rho GTPase-activating toxin CNF1. Consistently, this innate immune response is abrogated in caspase-1/11-impaired mice or following the treatment of infected mice with an IL-1 beta antagonist. In vitro experiments further revealed the synergistic effects of CNF1 and LPS in promoting the maturation/secretion of IL-1 beta and establishing the roles of Rac, ASC and caspase-1 in this pathway. Furthermore, we found that the Phi-hemolysin toxin inhibits IL-1 beta secretion without affecting the recruitment of Gr1+ cells. Here, we report the first example of anti-virulence-triggered immunity counteracted by a pore-forming toxin during bacteremia

    Functionalized superhydrophobic coatings with micro-/nanostructured ZnO particles in a sol–gel matrix

    Get PDF
    Among the methods to create superhydrophobic surfaces by wet chemistry, one of the strategies consists in coating the substrate with a hydrophobic polymer with specific morphology. Such elaborated surfaces are largely developed and can present complex architectures but are generally fragile. Ceramic-based coatings show better durability. In this work, a new route associating inorganic and polymeric parts is used. Surfaces with superhydrophobic properties are prepared with a mixture of zinc oxide (ZnO) particles in a hybrid organic inorganic matrix prepared via sol–gel route. ZnO particles were synthesized by the inorganic polycondensation route and exhibit an appropriate micro-/nanostructure for superhydrophobicity. Sol–gel matrix is obtained by the alkoxide route with aluminum-tri-secbutoxide (ASB) and (3-glycidoxypropyl)trimethoxysilane (GPTMS). A step of octadecylphosphonic acid (ODP) functionalization on ZnO particles and on film surfaces was employed to considerably improve hydrophobic properties. This new route enables to obtain superhydrophobic coatings that exhibitwater contact angles superior to 150°. These coatings show a homogeneous and smooth coverage on aluminum alloy substrate. Results attest the significance of the synergy for superhydrophobic coatings: a micro-/nanostructured surface and an intrinsic hydrophobic property of the material. The durability of the coatings has also been demonstrated with only a slight decrease in hydrophobicity after erosion

    Correlation between morphology and electrochemical behavior of chromium-free conversion coatings for aluminum alloys corrosion protection

    Get PDF
    Chromium(III)-based, tungstate-based and cerium(III)-based conversion coatings on AA2024-T3 are compared in terms of morphology and electrochemical behavior. The durability of coatings is studied under neutral salt spray conditions and in a weakly aggressive electrolyte composed of 0.1 mol/L Na2SO4 and 10−3 mol/L NaCl. The use of both microscopic and electrochemical analyses such as fitting of electrochemical impedance spectroscopy diagrams allows one to have a better insight into the influence of the interfacial and conversion layers on the degradation phenomena. The role of the remaining native interfacial oxide layer is particularly highlighted, its resistance being the highest at the beginning of the exposure. The degradation of the barrier effect of this interfacial layer is demonstrated to be closely related to the performances of the conversion layer both in terms of passive protection and a reservoir of corrosion inhibitor. Finally, coupled analyses from EIS fitting and microscopic observations allow one to reach a precise interpretation of the strengths and weak points of such system. This diagnostic is an important step towards the optimization of the chromium-free systems

    A New High-Throughput Tool to Screen Mosquito-Borne Viruses in Zika Virus Endemic/Epidemic Areas

    Get PDF
    International audienceMosquitoes are vectors of arboviruses affecting animal and human health. Arboviruses circulate primarily within an enzootic cycle and recurrent spillovers contribute to the emergence of human-adapted viruses able to initiate an urban cycle involving anthropophilic mosquitoes. The increasing volume of travel and trade offers multiple opportunities for arbovirus introduction in new regions. This scenario has been exemplified recently with the Zika pandemic. To incriminate a mosquito as vector of a pathogen, several criteria are required such as the detection of natural infections in mosquitoes. In this study, we used a high-throughput chip based on the BioMarkℱ Dynamic arrays system capable of detecting 64 arboviruses in a single experiment. A total of 17,958 mosquitoes collected in Zika-endemic/epidemic countries (Brazil, French Guiana, Guadeloupe, Suriname, Senegal, and Cambodia) were analyzed. Here we show that this new tool can detect endemic and epidemic viruses in different mosquito species in an epidemic context. Thus, this fast and low-cost method can be suggested as a novel epidemiological surveillance tool to identify circulating arboviruses

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

    Get PDF
    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 PitiĂ©-SalpĂȘtriĂšre 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

    Characterization of acute kidney injury in critically ill patients with severe coronavirus disease 2019

    Get PDF
    Abstract Background Coronavirus disease 2019 (COVID-19)-associated acute kidney injury (AKI) frequency, severity and characterization in critically ill patients has not been reported. Methods Single-centre cohort performed from 3 March 2020 to 14 April 2020 in four intensive care units in Bordeaux University Hospital, France. All patients with COVID-19 and pulmonary severity criteria were included. AKI was defined using Kidney Disease: Improving Global Outcomes (KDIGO) criteria. A systematic urinary analysis was performed. The incidence, severity, clinical presentation, biological characterization (transient versus persistent AKI; proteinuria, haematuria and glycosuria) and short-term outcomes were evaluated. Results Seventy-one patients were included, with basal serum creatinine (SCr) of 69 ± 21 ”mol/L. At admission, AKI was present in 8/71 (11%) patients. Median [interquartile range (IQR)] follow-up was 17 (12–23) days. AKI developed in a total of 57/71 (80%) patients, with 35% Stage 1, 35% Stage 2 and 30% Stage 3 AKI; 10/57 (18%) required renal replacement therapy (RRT). Transient AKI was present in only 4/55 (7%) patients and persistent AKI was observed in 51/55 (93%). Patients with persistent AKI developed a median (IQR) urine protein/creatinine of 82 (54–140) (mg/mmol) with an albuminuria/proteinuria ratio of 0.23 ± 20, indicating predominant tubulointerstitial injury. Only two (4%) patients had glycosuria. At Day 7 after onset of AKI, six (11%) patients remained dependent on RRT, nine (16%) had SCr >200 ”mol/L and four (7%) had died. Day 7 and Day 14 renal recovery occurred in 28% and 52%, respectively. Conclusion Severe COVID-19-associated AKI is frequent, persistent, severe and characterized by an almost exclusive tubulointerstitial injury without glycosuria

    Structure, Function, and Evolution of the Thiomonas spp. Genome

    Get PDF
    Bacteria of the Thiomonas genus are ubiquitous in extreme environments, such as arsenic-rich acid mine drainage (AMD). The genome of one of these strains, Thiomonas sp. 3As, was sequenced, annotated, and examined, revealing specific adaptations allowing this bacterium to survive and grow in its highly toxic environment. In order to explore genomic diversity as well as genetic evolution in Thiomonas spp., a comparative genomic hybridization (CGH) approach was used on eight different strains of the Thiomonas genus, including five strains of the same species. Our results suggest that the Thiomonas genome has evolved through the gain or loss of genomic islands and that this evolution is influenced by the specific environmental conditions in which the strains live

    Reduction in mortality from HIV-related CNS infections in routine care in Africa (DREAMM): a before-and-after, implementation study.

    Get PDF
    BACKGROUND: Four decades into the HIV epidemic, CNS infection remains a leading cause of preventable HIV-related deaths in routine care. The Driving Reduced AIDS-associated Meningo-encephalitis Mortality (DREAMM) project aimed to develop, implement, and evaluate pragmatic implementation interventions and strategies to reduce mortality from HIV-related CNS infection. METHODS: DREAMM took place in five public hospitals in Cameroon, Malawi, and Tanzania. The main intervention was a stepwise algorithm for HIV-related CNS infections including bedside rapid diagnostic testing and implementation of WHO cryptococcal meningitis guidelines. A health system strengthening approach for hospitals was adopted to deliver quality care through a co-designed education programme, optimised clinical and laboratory pathways, and communities of practice. DREAMM was led and driven by local leadership and divided into three phases: observation (including situational analyses of routine care), training, and implementation. Consecutive adults (aged ≄18 years) living with HIV presenting with a first episode of suspected CNS infection were eligible for recruitment. The primary endpoint was the comparison of 2-week all-cause mortality between observation and implementation phases. This study completed follow-up in September, 2021. The project was registered on ClinicalTrials.gov, NCT03226379. FINDINGS: From November, 2016 to April, 2019, 139 eligible participants were enrolled in the observation phase. From Jan 9, 2018, to March 25, 2021, 362 participants were enrolled into the implementation phase. 216 (76%) of 286 participants had advanced HIV disease (209 participants had missing CD4 cell count), and 340 (69%) of 494 participants had exposure to antiretroviral therapy (ART; one participant had missing ART data). In the implementation phase 269 (76%) of 356 participants had a probable CNS infection, 203 (76%) of whom received a confirmed microbiological or radiological diagnosis of CNS infection using existing diagnostic tests and medicines. 63 (49%) of 129 participants died at 2 weeks in the observation phase compared with 63 (24%) of 266 in the implementation phase; and all-cause mortality was lower in the implementation phase when adjusted for site, sex, age, ART exposure (adjusted risk difference -23%, 95% CI -33 to -13; p<0·001). At 10 weeks, 71 (55%) died in the observation phase compared with 103 (39%) in the implementation phase (-13%, -24 to -3; p=0·01). INTERPRETATION: DREAMM substantially reduced mortality from HIV-associated CNS infection in resource-limited settings in Africa. DREAMM scale-up is urgently required to reduce deaths in public hospitals and help meet Sustainable Development Goals. FUNDING: European and Developing Countries Clinical Trials Partnership, French Agency for Research on AIDS and Viral Hepatitis. TRANSLATIONS: For the French and Portuguese translations of the abstract see Supplementary Materials section
    • 

    corecore