Impact de la diversité génétique des communautés prairiales sur la production et la biodiversité du sol : Implications pour l'amélioration des plantes

Many studies highlight a positive effect of species diversity on plant community productivity and associated biodiversity. But genetic diversity effect on species community is still poorly studied despite the rare studies showing a positive effect with prospects for application in the field of plant breeding. It is in this context that this thesis examines the genetic diversity effect on grassland communities and associated soil biodiversity. This thesis is based on a real situation via an evaluation design of grassland mixtures installed by and in a plants breeding company. The major results of this thesis are a positive effect of the species genetic diversity on mixture biomass production, especially during drought episodes, and on species abundance equilibrium. These positive effects seem to be the result of a niche differentiation of species which is at the basis of species complementarity in ecology. Temporal complementarity of species has been demonstrated by asynchronous growth dynamics, but also by a complementarity for light acquisition via selection and plasticity mechanisms. Finally, genetic diversity effects have been observed on microbial diversity with plants feedbacks. In view of these results, it appears that genetic diversity occupies a central role in the assembly and structure of plant and microbial communities, leading us to consider how it could be integrated into plant breeding program.De nombreuses études mettent en évidence un effet positif de la diversité spécifique sur la productivité des communautés végétales et la biodiversité associée. Mais l’effet de la diversité génétique sur la communauté d’espèces reste encore peu étudié en dépit des rares études montrant un effet positif avec des perspectives d’application dans le domaine de l’amélioration des plantes. C’est dans ce contexte que cette thèse s’interroge sur l’effet de la diversité génétique sur les communautés prairiales et la biodiversité du sol associée. Cette thèse repose sur une situation réelle via un dispositif d’évaluation de mélanges prairiaux installé par et chez un sélectionneur de plantes fourragères. Les résultats majeurs de cette thèse sont un effet positif de la diversité génétique des espèces sur la production de biomasse du mélange, particulièrement lors d’épisodes de sècheresse, et sur l’équilibre d’abondance des espèces. Ces effets positifs semblent être le résultat d’une différenciation de niches des espèces qui est à la base de la complémentarité des espèces en écologie. Il a été mis en évidence une complémentarité temporelle des espèces par une asynchronie des dynamiques de croissance, mais aussi une complémentarité sur l’acquisition de la lumière par des mécanismes de sélection et de plasticité. Enfin, des effets de la diversité génétique ont été observés sur la diversité microbienne avec des rétroactions potentielles sur les plantes. Au vu de ces résultats, il apparait que la diversité génétique occupe une place centrale dans l’assemblage et la structuration des communautés végétales et microbiennes, nous amenant à réfléchir quant à sa valorisation en amélioration des plantes

Impact of genetic diversity on production and soil biodiversity in grassland communities : Implications for plant breeding

De nombreuses études mettent en évidence un effet positif de la diversité spécifique sur la productivité des communautés végétales et la biodiversité associée. Mais l’effet de la diversité génétique sur la communauté d’espèces reste encore peu étudié en dépit des rares études montrant un effet positif avec des perspectives d’application dans le domaine de l’amélioration des plantes. C’est dans ce contexte que cette thèse s’interroge sur l’effet de la diversité génétique sur les communautés prairiales et la biodiversité du sol associée. Cette thèse repose sur une situation réelle via un dispositif d’évaluation de mélanges prairiaux installé par et chez un sélectionneur de plantes fourragères. Les résultats majeurs de cette thèse sont un effet positif de la diversité génétique des espèces sur la production de biomasse du mélange, particulièrement lors d’épisodes de sècheresse, et sur l’équilibre d’abondance des espèces. Ces effets positifs semblent être le résultat d’une différenciation de niches des espèces qui est à la base de la complémentarité des espèces en écologie. Il a été mis en évidence une complémentarité temporelle des espèces par une asynchronie des dynamiques de croissance, mais aussi une complémentarité sur l’acquisition de la lumière par des mécanismes de sélection et de plasticité. Enfin, des effets de la diversité génétique ont été observés sur la diversité microbienne avec des rétroactions potentielles sur les plantes. Au vu de ces résultats, il apparait que la diversité génétique occupe une place centrale dans l’assemblage et la structuration des communautés végétales et microbiennes, nous amenant à réfléchir quant à sa valorisation en amélioration des plantes.Many studies highlight a positive effect of species diversity on plant community productivity and associated biodiversity. But genetic diversity effect on species community is still poorly studied despite the rare studies showing a positive effect with prospects for application in the field of plant breeding. It is in this context that this thesis examines the genetic diversity effect on grassland communities and associated soil biodiversity. This thesis is based on a real situation via an evaluation design of grassland mixtures installed by and in a plants breeding company. The major results of this thesis are a positive effect of the species genetic diversity on mixture biomass production, especially during drought episodes, and on species abundance equilibrium. These positive effects seem to be the result of a niche differentiation of species which is at the basis of species complementarity in ecology. Temporal complementarity of species has been demonstrated by asynchronous growth dynamics, but also by a complementarity for light acquisition via selection and plasticity mechanisms. Finally, genetic diversity effects have been observed on microbial diversity with plants feedbacks. In view of these results, it appears that genetic diversity occupies a central role in the assembly and structure of plant and microbial communities, leading us to consider how it could be integrated into plant breeding program

Antioxidant and Cytoprotective Properties of Polyphenol-Rich Extracts from Antirhea borbonica and Doratoxylon apetalum against Atherogenic Lipids in Human Endothelial Cells

The endothelial integrity is the cornerstone of the atherogenic process. Low-density lipoprotein (LDL) oxidation occurring within atheromatous plaques leads to deleterious vascular effects including endothelial cell cytotoxicity. The aim of this study was to evaluate the vascular antioxidant and cytoprotective effects of polyphenol-rich extracts from two medicinal plants from the Reunion Island: Antirhea borbonica (A. borbonica), Doratoxylon apetalum (D. apetalum). The polyphenol-rich extracts were obtained after dissolving each dry plant powder in an aqueous acetonic solution. Quantification of polyphenol content was achieved by the Folin–Ciocalteu assay and total phenol content was expressed as g gallic acid equivalent/100 g plant powder (GAE). Human vascular endothelial cells were incubated with increasing concentrations of polyphenols (1–50 µM GAE) before stimulation with oxidized low-density lipoproteins (oxLDLs). LDL oxidation was assessed by quantification of hydroperoxides and thiobarbituric acid reactive substances (TBARS). Intracellular oxidative stress and antioxidant activity (catalase and superoxide dismutase) were measured after stimulation with oxLDLs. Cell viability and apoptosis were quantified using different assays (MTT, Annexin V staining, cytochrome C release, caspase 3 activation and TUNEL test). A. borbonica and D. apetalum displayed high levels of polyphenols and limited LDL oxidation as well as oxLDL-induced intracellular oxidative stress in endothelial cells. Polyphenol extracts of A. borbonica and D. apetalum exerted a protective effect against oxLDL-induced cell apoptosis in a dose-dependent manner (10, 25, and 50 µM GAE) similar to that observed for curcumin, used as positive control. All together, these results showed significant antioxidant and antiapoptotic properties for two plants of the Reunion Island pharmacopeia, A. borbonica and D. apetalum, suggesting their therapeutic potential to prevent cardiovascular diseases by limiting LDL oxidation and protecting the endothelium

Intraflagellar Transport Complex B Proteins Regulate the Hippo Effector Yap1 during Cardiogenesis.

Cilia and the intraflagellar transport (IFT) proteins involved in ciliogenesis are associated with congenital heart diseases (CHDs). However, the molecular links between cilia, IFT proteins, and cardiogenesis are yet to be established. Using a combination of biochemistry, genetics, and live-imaging methods, we show that IFT complex B proteins (Ift88, Ift54, and Ift20) modulate the Hippo pathway effector YAP1 in zebrafish and mouse. We demonstrate that this interaction is key to restrict the formation of the proepicardium and the myocardium. In cellulo experiments suggest that IFT88 and IFT20 interact with YAP1 in the cytoplasm and functionally modulate its activity, identifying a molecular link between cilia-related proteins and the Hippo pathway. Taken together, our results highlight a noncanonical role for IFT complex B proteins during cardiogenesis and shed light on a mechanism of action for ciliary proteins in YAP1 regulation.This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement No. 708312 (M.P.) and from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme: GA No. 682938 (J.V.). This work was supported by FRM (DEQ20140329553), by ANR (ANR-15-CE13-0015–liveheart, ANR- SNF310030E-164245-forcinregeneration), and by the Grant ANR-10-LABX-0030-INRT, a French State fund managed by the Agence Nationale de la Recherche under the frame program Investissements d’Avenir labeled ANR-10-IDEX-0002-02. B.D.’s team was supported by ANR-12-CHEX-005 and CNRS. S.M.M.’s team was supported by core funding from the Institut Imagine, Institut Pasteur, Inserm, Universite´ Paris Descartes, and a grant from the AFM-Te´ le´ thon Trampoline 18727). T.L. was funded by the ED515 (1691/2014). L.O.L. is supported by the European Commission (H2020-MSCA-ITN-2016 European Industrial Doctorate 4DHeart 722427).S

Distribution of Adiponectin Receptors in the Brain of Adult Mouse: Effect of a Single Dose of the Adiponectin Receptor Agonist, AdipoRON, on Ischemic Stroke

Adiponectin exhibits pleiotropic effects, including anti-inflammatory, anti-apoptotic, antioxidant, and neuroprotective ones. Although some studies have documented brain expression in different rodent models of its receptors, AdipoR1 and AdipoR2, their global distribution remains incomplete. Here, we demonstrated that both AdipoR are widely distributed in the brains of adult mice. Furthermore, by double immunostaining studies, we showed that AdipoR1 and AdipoR2 are mainly expressed in neurons and blood vessels. Then, considering the wide distribution of both receptors and the neuroprotective effects of adiponectin, we tested the therapeutic effect of a single injection of the adiponectin receptor agonist, AdipoRON (5 mg.kg −1), 24 h after stroke in a model of middle cerebral artery occlusion technique (MCAO). Under our experimental conditions, we demonstrated that AdipoRON did not modulate the infarct volume, cell death, neuroinflammatory parameters including microglia activation and oxidative stress. This study suggests that a protocol based on multiple injections of AdipoRON at a higher dose after MCAO could be considered to promote the therapeutic properties of AdipoRON on the brain repair mechanism and recovery

Immaturity of microvessels in haemorrhagic plaques is associated with proteolytic degradation of angiogenic factors

AIMS We investigated the causes of microvessel immaturity and destabilization in human atherosclerotic lesions. METHODS AND RESULTS Human atherosclerotic carotid plaques (n = 24) were classified as non-haemorrhagic (NH) or haemorrhagic (Hem), according to their macroscopic aspect and haemoglobin content. Plaque microvessel density and maturity were quantified by immunohistochemistry. Expression of angiogenic factors was studied by immunohistochemistry, in situ hybridization, and ELISA. Plaque-conditioned media were tested for plasmin and elastase activities and for their ability to degrade angiogenic factors and to induce smooth muscle cell migration. Microvessel density and leucocyte infiltration were increased in Hem compared with NH plaques. Plaque vasculature appeared vulnerable as indicated by the absence of alpha-actin-positive mural cells in most plaque vessels. Despite increased numbers of angiogenic factor-expressing microvessels and leucocytes in Hem plaques, lower levels of vascular endothelial growth factor, placental growth factor, and angiopoietin-1 were found in conditioned media from Hem plaques. However, NH and Hem plaques released similar levels of the vascular destabilizing factor, angiopoietin-2. Addition of recombinant angiogenic factors to plaque extracts showed that all factors but angiopoietin-2 were selectively degraded by plasmin and/or elastase released from Hem plaques. Furthermore, conditioned media from Hem plaques showed a reduced ability to induce smooth muscle cell migration. CONCLUSION Our results provide evidence that immaturity of plaque vessels is associated with the degradation of angiogenic factors by haemorrhage-conveyed leucocytes and proteases

MOESM3 of Low HDL levels in sepsis versus trauma patients in intensive care unit

Additional file 3. Manuscript database

Extracellular Vesicles Are Conveyors of the NS1 Toxin during Dengue Virus and Zika Virus Infection

Extracellular vesicles (EVs), produced during viral infections, are of emerging interest in understanding infectious processes and host–pathogen interactions. EVs and exosomes in particular have the natural ability to transport nucleic acids, proteins, and other components of cellular or viral origin. Thus, they participate in intercellular communication, immune responses, and infectious and pathophysiological processes. Some viruses are known to hijack the cell production and content of EVs for their benefit. Here, we investigate whether two pathogenic flaviviruses i.e., Zika Virus (ZIKV) and Dengue virus (DENV2) could have an impact on the features of EVs. The analysis of EVs produced by infected cells allowed us to identify that the non-structural protein 1 (NS1), described as a viral toxin, is associated with exosomes. This observation could be confirmed under conditions of overexpression of recombinant NS1 from each flavivirus. Using different isolation methods (i.e., exosome isolation kit, size exclusion chromatography, Polyethylene Glycol enrichment, and ELISA capture), we showed that NS1 was present as a dimer at the surface of excreted exosomes, and that this association could occur in the extracellular compartment. This finding could be of major importance in a physiological context. Indeed, this capacity of NS1 to address EVs and its implication in the pathophysiology during Dengue or Zika diseases should be explored. Furthermore, exosomes that have demonstrated a natural capacity to vectorize NS1 could serve as useful tools for vaccine development

Extracellular Vesicles Are Conveyors of the NS1 Toxin during Dengue Virus and Zika Virus Infection

Extracellular vesicles (EVs), produced during viral infections, are of emerging interest in understanding infectious processes and host–pathogen interactions. EVs and exosomes in particular have the natural ability to transport nucleic acids, proteins, and other components of cellular or viral origin. Thus, they participate in intercellular communication, immune responses, and infectious and pathophysiological processes. Some viruses are known to hijack the cell production and content of EVs for their benefit. Here, we investigate whether two pathogenic flaviviruses i.e., Zika Virus (ZIKV) and Dengue virus (DENV2) could have an impact on the features of EVs. The analysis of EVs produced by infected cells allowed us to identify that the non-structural protein 1 (NS1), described as a viral toxin, is associated with exosomes. This observation could be confirmed under conditions of overexpression of recombinant NS1 from each flavivirus. Using different isolation methods (i.e., exosome isolation kit, size exclusion chromatography, Polyethylene Glycol enrichment, and ELISA capture), we showed that NS1 was present as a dimer at the surface of excreted exosomes, and that this association could occur in the extracellular compartment. This finding could be of major importance in a physiological context. Indeed, this capacity of NS1 to address EVs and its implication in the pathophysiology during Dengue or Zika diseases should be explored. Furthermore, exosomes that have demonstrated a natural capacity to vectorize NS1 could serve as useful tools for vaccine development

Effectiveness of Simulation-Based Training on Transesophageal Echocardiography Learning

Importance Evidence is scarce on the effectiveness of simulation-based training in transesophageal echocardiography (TEE).Objective To assess the effectiveness of simulation-based teaching vs traditional teaching of TEE knowledge and skills of cardiology fellows.Design, Setting, and Participants Between November 2020 and November 2021, all consecutive cardiology fellows inexperienced in TEE from 42 French university centers were randomized (1:1; n = 324) into 2 groups with or without simulation support.Main Outcomes and Measures The co-primary outcomes were the scores in the final theoretical and practical tests 3 months after the training. TEE duration and the fellows’ self-assessment of their proficiency were also assessed.Results While the theoretical and practical test scores were similar between the 2 groups (324 participants; 62.6% male; mean age, 26.4 years) before the training (33.0 [SD, 16.3] points vs 32.5 [SD, 18.5] points; P = .80 and 44.2 [SD, 25.5] points vs 46.1 [SD, 26.1] points; P = .51, respectively), the fellows in the simulation group (n = 162; 50%) displayed higher theoretical test and practical test scores after the training than those in the traditional group (n = 162; 50%) (47.2% [SD, 15.6%] vs 38.3% [SD, 19.8%]; P < .001 and 74.5% [SD, 17.7%] vs 59.0% [SD, 25.1%]; P < .001, respectively). Subgroup analyses showed that the effectiveness of the simulation training was even greater when performed at the beginning of the fellowship (ie, 2 years or less of training) (theoretical test: an increase of 11.9 points; 95% CI, 7.2-16.7 vs an increase of 4.25 points; 95% CI, −1.05 to 9.5; P = .03; practical test: an increase of 24.9 points; 95% CI, 18.5-31.0 vs an increase of 10.1 points; 95% CI, 3.9-16.0; P < .001). After the training, the duration to perform a complete TEE was significantly lower in the simulation group than in the traditional group ( 8.3 [SD, 1.4] minutes vs 9.4 [SD, 1.2] minutes; P < .001, respectively). Additionally, fellows in the simulation group felt more ready and more confident about performing a TEE alone after the training (mean score, 3.0; 95% CI, 2.9-3.2 vs mean score, 1.7; 95% CI, 1.4-1.9; P < .001 and mean score, 3.3; 95% CI, 3.1-3.5 vs mean score, 2.4; 95% CI, 2.1-2.6; P < .001, respectively).Conclusions and Relevance Simulation-based teaching of TEE showed a significant improvement in the knowledge, skills, and self-assessment of proficiency of cardiology fellows, as well as a reduction in the amount of time needed to complete the examination. These results should encourage further investigation of clinical performance and patient benefits of TEE simulation training.Trial Registration ClinicalTrials.gov Identifier: NCT0556450