41 research outputs found

    Magpies as Hosts for West Nile Virus, Southern France

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    European magpies (Pica pica) from southern France were tested for antibodies to West Nile virus (WNV) and viral shedding in feces during spring–autumn 2005. Results suggest that this peridomestic species may be a suitable sentinel species and a relevant target for additional investigations on WNV ecology in Europe

    Evolution of the Plant Reproduction Master Regulators LFY and the MADS Transcription Factors: The Role of Protein Structure in the Evolutionary Development of the Flower.

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    International audienceUnderstanding the evolutionary leap from non-flowering (gymnosperms) to flowering (angiosperms) plants and the origin and vast diversification of the floral form has been one of the focuses of plant evolutionary developmental biology. The evolving diversity and increasing complexity of organisms is often due to relatively small changes in genes that direct development. These "developmental control genes" and the transcription factors (TFs) they encode, are at the origin of most morphological changes. TFs such as LEAFY (LFY) and the MADS-domain TFs act as central regulators in key developmental processes of plant reproduction including the floral transition in angiosperms and the specification of the male and female organs in both gymnosperms and angiosperms. In addition to advances in genome wide profiling and forward and reverse genetic screening, structural techniques are becoming important tools in unraveling TF function by providing atomic and molecular level information that was lacking in purely genetic approaches. Here, we summarize previous structural work and present additional biophysical and biochemical studies of the key master regulators of plant reproduction - LEAFY and the MADS-domain TFs SEPALLATA3 and AGAMOUS. We discuss the impact of structural biology on our understanding of the complex evolutionary process leading to the development of the bisexual flower

    The Arabidopsis Putative Selenium-Binding Protein Family: Expression Study and Characterization of SBP1 as a Potential New Player in Cadmium Detoxification Processes

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    International audienceIn Arabidopsis thaliana, the putative selenium-binding protein gene family is made of 3 members (SBP 1 to 3). RT-PCR analyses showed that SBP1 expression was ubiquitous. SBP2 was expressed at a lower level in flowers and roots whereas SBP3 transcripts were only detected in young seedling tissues. In Cd-treated seedlings, SBP1 level of expression was rapidly increased in roots. In shoots, SBP1 transcripts accumulated later and for higher Cd doses. SBP2 and SBP3 expression showed delayed or no responsiveness to Cd. In addition, luciferase (LUC) activity recorded on Arabidopsis lines expressing the LUC gene under the control of SBP1 promoter further showed dynamic regulation of SBP1 expression during development and in response to Cd stress. Western blot analysis using polyclonal antibodies raised against SBP1 showed that SBP1 protein accumulated in Cd-exposed tissues in correlation with SBP1 transcript amount. The sbp1 null mutant displayed no visible phenotype under normal and stress conditions that was explained by the up regulation of SBP2 expression. SBP1 over-expression enhanced Cd accumulation in roots and reduced sensitivity to Cd in WT and more significantly in Cd-hypersensitive cad mutants that lack phytochelatins. Similarly in Saccharomyces cerevisiae, SBP1 expression led to increased Cd tolerance of the Cd-hypersensitive ycf1 mutant. In vitro experiments showed that SBP1 has the ability to bind Cd. These data highlight the importance of maintaining the adequate SBP protein level under healthy and stress conditions and suggest that during Cd stress, SBP1 accumulation efficiently helps to detoxify Cd potentially through direct binding

    Arabidopsis Putative Selenium-Binding Protein1 Expression Is Tightly Linked to Cellular Sulfur Demand and Can Reduce Sensitivity to Stresses Requiring Glutathione for Tolerance1[W]

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    Selenium-Binding Protein1 (SBP1) gene expression was studied in Arabidopsis (Arabidopsis thaliana) seedlings challenged with several stresses, including cadmium (Cd), selenium {selenate [Se(VI)] and selenite [Se(IV)]}, copper (Cu), zinc (Zn), and hydrogen peroxide (H2O2) using transgenic lines expressing the luciferase (LUC) reporter gene under the control of the SBP1 promoter. In roots and shoots of SBP1∷LUC lines, LUC activity increased in response to Cd, Se(VI), Cu, and H2O2 but not in response to Se(IV) or Zn. The pattern of expression of SBP1 was similar to that of PRH43, which encodes the 5′-Adenylylphosphosulfate Reductase2, a marker for the induction of the sulfur assimilation pathway, suggesting that an enhanced sulfur demand triggers SBP1 up-regulation. Correlated to these results, SBP1 promoter showed enhanced activity in response to sulfur starvation. The sulfur starvation induction of SBP1 was abolished by feeding the plants with glutathione (GSH) and was enhanced when seedlings were treated simultaneously with buthionine sulfoxide, which inhibits GSH synthesis, indicating that GSH level participates in the regulation of SBP1 expression. Changes in total GSH level were observed in seedlings challenged with Cd, Se(VI), and H2O2. Accordingly, cad2-1 seedlings, affected in GSH synthesis, were more sensitive than wild-type plants to these three stresses. Moreover, wild-type and cad2-1 seedlings overexpressing SBP1 showed a significant enhanced tolerance to Se(VI) and H2O2 in addition to the previously described resistance to Cd, highlighting that SBP1 expression decreases sensitivity to stress requiring GSH for tolerance. These results are discussed with regard to the potential regulation and function of SBP1 in plants

    Birdspecies potentially involved in introduction, amplification, and spread of West Nile Virus in a Mediterranean Wetland, the Camargue (Southern France)

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    International audienceWest Nile virus (WNV) is a mosquito-transmitted Flavivirus with a transmission cycle involving birds as amplifying hosts. Wild birds are also believed to carry WNV over large distances and are able to introduce it into new areas during migration and dispersal. In this paper, our objective is to provide lists of birds potentially involved in the introduction, the amplification and the spread of WNV in the Camargue, a Mediterranean wetland in the south of France where several WNV outbreaks have occurred since the 1960s. Bird species were classified according to the following ecological factors: migratory status and provenance area, used biotopes, abundance and period of presence in the Camargue. The obtained lists of bird species potentially involved in the introduction, amplification and spread of WNV should prove useful to determine target species on which further studies on WNV ecology in birds could be focused

    Effectiveness and Medicoeconomic Evaluation of Home Monitoring of Patients With Mild COVID-19: Covidom Cohort Study

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    International audienceBackground Covidom was a telemonitoring solution for home monitoring of patients with mild to moderate COVID-19, deployed in March 2020 in the Greater Paris area in France to alleviate the burden on the health care system. The Covidom solution included a free mobile application with daily monitoring questionnaires and a regional control center to quickly handle patient alerts, including dispatching emergency medical services when necessary. Objective This study aimed to provide an overall evaluation of the Covidom solution 18 months after its inception in terms of effectiveness, safety, and cost. Methods Our primary outcome was to measure effectiveness using the number of handled alerts, response escalation, and patient-reported medical contacts outside of Covidom. Then, we analyzed the safety of Covidom by assessing its ability to detect clinical worsening, defined as hospitalization or death, and the number of patients with clinical worsening without any preceding alert. We evaluated the cost of Covidom and compared the cost of hospitalization for Covidom and non-Covidom patients with mild COVID-19 cases seen in the emergency departments of the largest network of hospitals in the Greater Paris area (Assistance Publique-Hôpitaux de Paris). Finally, we reported on user satisfaction. Results Of the 60,073 patients monitored by Covidom, the regional control center handled 285,496 alerts and dispatched emergency medical services 518 times. Of the 13,204 respondents who responded to either of the follow-up questionnaires, 65.8% (n=8690) reported having sought medical care outside the Covidom solution during their monitoring period. Of the 947 patients who experienced clinical worsening while adhering to daily monitoring, only 35 (3.7%) did not previously trigger alerts (35 were hospitalized, including 1 who died). The average cost of Covidom was €54 (US $1=€0.8614) per patient, and the cost of hospitalization for COVID-19 worsening was significantly lower in Covidom than in non-Covidom patients with mild COVID-19 cases seen in the emergency departments of Assistance Publique-Hôpitaux de Paris. The patients who responded to the satisfaction questionnaire had a median rating of 9 (out of 10) for the likelihood of recommending Covidom. Conclusions Covidom may have contributed to alleviating the pressure on the health care system in the initial months of the pandemic, although its impact was lower than anticipated, with a substantial number of patients having consulted outside of Covidom. Covidom seems to be safe for home monitoring of patients with mild to moderate COVID-19

    Prognosis of Rash and Chilblain-like Lesions among Outpatients with COVID-19: A Large Cohort Study

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    International audienceIn a large regional observational cohort study of adult (≥ 18 years), outpatients with COVID-19, prevalence, characteristics, and outcome of patients with rash and/or chilblain-like lesions (CLL), compared with population without cutaneous features, were studied. In total, 28,957 outpatients were included; the prevalence of rash and CCL were 9.5% and 3.7%, respectively. Presence of rash was significantly associated with presence of asthenia, shivers or myalgia, respiratory and gastro-intestinal symptoms, and anosmia/ageusia. The presence of CCL was associated with chest pain, chest oppression, nausea/vomiting, and anosmia/ageusia. Patients with CCL were significantly less prone to an unfavourable outcome (hospitalization or death)
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