Evolution de la biocénose rotatorienne au cours des variations de l'état trophique du Léman et comparaison avec le lac de Constance

L'évolution comparée des biocénoses rotatoriennes du Léman et du Lac de Constance montre un parallélisme remarquable lors des changements continus de l'état trophique, tant avant qu'après le niveau maximal d'eutrophisation atteint par ces deux lacs. La comparaison avec un certain nombre d'autres milieux soumis également à un changement de leur niveau trophique met en évidence une variation très nette des effectifs des espèces méso-eutrophes et eutrophes en fonction de la progression ou de la régression de l'eutrophisation; ces changements sont beaucoup moins marqués en ce qui concerne l'association des espèces oligo-mésotrophes.Eutrophication of a lake must be expected to cause both abiotic and biotic responses. The changes in the trophic state of a lake certainly occur at all trophic levels, but to different extents depending on the character of the ecosystem; the subsequent evolution of the rotifer biocenosis is one of the most pronounced features occurring as an indirect consequence of eutrophication.In the last three decades, the rotifer community in Lake Geneva has presented important changes in structure, as a result of continuous changes in the trophism of the lake. This study covered a period of time sufficient to show possible true modifications of the community structure.Lake Geneva has undergone anthropogenic eutrophication since the 1950's. The lake reached its highest nutrient level during 1979-1980, which has decreased though since 1981 with the improvement of phosphorus removal in sewage treatment plants. A similar trend was observed in Lake Constance, with more important quantitative changes connected with previous results dating from the oligotrophic stage of this lake.Table 1 gives the variations in abundance of rotifer species observed during the eutrophication increase and during the decrease of the eutrophication level in some lakes of different trophic status.Figure 1 indicates the quantitative changes of the main rotifer species in Lake Geneva and Lake Constance. Compared to the maximal trophic level (indicated by arrow), data from Lake Geneva for 1959-1987 are similar to those obtained in Lake Constance between 1963 and 1978, if the previous data obtained for this lake during its oligotrophic stage are excluded.Figure 2 presents the general trend observed for the different trophic indicator groups during the increase or decrease of eutrophication. Throughout the eutrophication process, these groups exhibited a general increase for most of the different species, with the ratio "number of increasing species/number of decreasing species" growing from the oligo-mesotrophic group to the eutrophic one. During the decrease of eutrophication, the strength of meso-eutrophic and eutrophic indicator groups diminished more than that of the oligomesotrophic group.Many species have appeared during the eutrophication increase, mainly belonging to meso-eutrophic and eutrophic indicator groups, together with the settlement of some oligo-mesotrophicspecies (Ascomorpha saltans, Synchaeta oblonga, Notholca caudata). The proportion of meso-eutrophic and eutrophic species increased in the two lakes, but there is a trend in populations of the oligo-mesotrophic species to decrease, leading to a precocious disappearance of Ploesoma hudsoni and later of Ascomorpha ovalis, Gastropus stylifer, Ploesoma truncatum in Lake Constance, and of Synchaeta tremula and Notholca foliacea in both lakes.Decreasing eutrophication reduces the number of some mesoeutrophic (Trichocerca longiseta and T. pusilla in Lake Geneva, T. rousseleti in Lake Constance) and eutrophic species (Anuraeopsis fissa and Trichocera cylindrica in Lake Geneva, Pompholyx complanta in Lake Constance). However, the water quality has mot improved enough to allow a further increase in oligo-mesotrophic species, except for Conochilus unicornis in both lakes, and for Ascomorpha ecaudis, Kellicottia longispina and Synchaeta oblonga in Lake Geneva.Since 1981, the oligo-mesotrophic indicator group is numerically dominant in Lake Geneva (BALVAY and LAURENT, 1989c), preceding the euryecious one (Asplanchna priodonta + Keratella cochlearis), white the strength of the meso-eutrophic group decreases and the eutrophic one remains almost steady

Relargage du phosphore à l'interface eau-sédiment dans des étangs de pisciculture de la station Deroua (Béni Mellal, Maroc)

De l'urée et du super phosphate triple ont été appliqués aux étangs d'alevinage de carpes chinoises de la station Deroua pour stimuler la croissance des algues. Toutefois, une forte proportion de ce phosphore est fixée par les sédiments et sera libérée en grande quantité dans les étangs lorsque les sédiments sont en conditions anaérobies.Nous avons étudié le relargage des orthophosphates par les sédiments provenant de deux étangs différents. L'un (A1) en terre ce qui permet la percolation des éléments nutritifs vers les couches profondes, l'autre (C1) dont le fond recouvert d'une fine membrane en polyéthylène, est parfaitement imperméable et empêche toute perte. Par ailleurs, nous avons étudié les effets de l'oxygène dissous, du pH, des nitrates et du glucose sur le relargage des orthophosphates par les sédiments.Les résultats obtenus montrent qu'en anaérobiose, la solubilité du phosphore augmente dans l'eau interstitielle. Les orthophosphates libérés, dont la concentration peut atteindre 873 µg/l, proviennent de la fraction minérale en particulier du Fe(OOH)=P. Le sédiment C1 qui accumule de grandes quantités de matière organique libère plus de phosphore que le sédiment A1.L'addition des nitrates limite la mobilisation du phosphore à partir des sédiments. Le pH acide provoque la dissolution du phosphore lié au calcium alors qu'un pH alcalin provoque celle du phosphore lié aux hydroxydes de fer et sa précipitation partielle sur les carbonates présents dans les sédiments.In the Deroua fish farm (Béni-Mellal, Morocco), a series of ponds was lined with polyethylene to prevent water seepage (lined ponds, C). Another series of ponds was not lined (unlined ponds, A). The lined ponds do not need much fertiliser to enhance phytoplankton growth. They receive a small quantity of urea and triple super phosphate and accumulate high levels of organic matter in their sediments. The unlined ponds receive a large quantity of fertilisers. In the ponds, an important increase in phytoplankton growth occurred particularly after fertilisation with triple super phosphate. The phosphate (P) released from the sediment is the essential source of P for phytoplankton when the ponds are not fertilised.Sediment samples used in this study were collected in June 1999 from the A1 and C1 ponds of the Deroua fish farm. The bottom sediments were collected with a core sampler to provide samples from the 0-5 cm layer. The samples were mixed and analysed for pH, total Kjeldahl nitrogen (NTK), nitrates (N-NO3-), ammonium (N-NH4+), total iron (tot-Fe) and P-fractionation in eight replicates, using the Golterman method (1996).In this work, experiments were conducted to evaluate the P released from sediments of lined and unlined ponds under controlled conditions. The samples included: untreated sediments, sediments treated with hydrogen peroxide (H2O2), and sediments treated with chloroform (CHCl3). H2O2 was used to destroy the organic matter of sediment. To inactivate bacteria, CHCl3 was added to the sediments. CHCl3 does not modify the mineral and organic structures of sediments but does reduce the bacterial biomass. Urea and triple super phosphate were added to Chinese carp rearing ponds at Deroua fisheries farm to stimulate algal growth. However, phosphate bound to the sediments was released into the water column during anaerobic conditions. The released phosphate from lined pond (C1) enhanced the algal production.We have tested the fertilisation capacity of A1 and C1 ponds as well as the effects of different factors such as dissolved oxygen, pH, nitrate, and organic matter (glucose) on the phosphate released from the sediments. The results show that under anoxic conditions, phosphate solubility increased in the interstitial water. The released phosphate (873 µg/l) comes from the mineral fraction, particularly from Fe(OOH)=P. The P released from the A1 untreated sediment under oxic and anoxic conditions was low in comparison to the P released from the C1 untreated sediment and did not exceed 9.1 µg.g-1 d.w. (Figure 1). The removal of organic matter with H2O2 had a positive effect on the P released from the C1 sediments only after the second day of incubation. The inactivation of bacteria with CHCl3 had an inhibitory effect on the P released from the C1 sediments under oxic and anoxic conditions; however for the A1 sediments, this inactivation of bacteria had no effect on the kinetics of P release. Phosphorus release from the C1 sediments was important under anoxic conditions; the P came from Fe(OOH)=P after the reduction of Fe(OOH).The addition of nitrates decreased the mobilisation of phosphate from the sediments. Acid conditions increased the dissolution of calcium-bound phosphate, while alkaline conditions increased the dissolution of iron-bound phosphate and its re-precipitation onto carbonate present in sediments. High concentrations of organic matter (glucose) increased oxygen demand and favoured the development of reducing conditions. The phosphate was released from Fe(OOH)=P.The conceptual model of P released in fish ponds shows that, in semiarid climates and in calcareous areas, the polyethylene lining of ponds prevents not only the seepage of water but also the percolation of nutrients. Consequently, the P was more available for algal uptake in the lined ponds. More phosphate will be released concomitant with the process of the ponds becoming anoxic, as nitrate concentrations and the pH of sediments decrease

MULTIPASS: gestion des consentements pour accéder aux données des exploitations dans une chaîne de confiance afin de favoriser l'émergence de nouveaux services pour les agriculteurs

12th EFITA International Conference, Rhode island, GRC, 27-/06/2019 - 29/06/2019International audienceWith the emergence of digital technologies, farms become a relevant source of data to meet the challenges of multi-performance agriculture. Beyond the services provided, access to farmers' data depends on a clear understanding of their use, which must be done in a transparent way. Several codes of conduct at a national or international level push for a voluntary commitment to respect some good practices in the use of agricultural data. To provide a tool and answer farmer's questions on the control of their data and the transparency of the data processing, the partners of the MULTIPASS project, have imagined an interoperable ecosystem of farmer consents management, protecting farmers from no consented uses of their data.Farmers' expectations of such an ecosystem have been expressed during workshops. They want to better identify existing data flows, including actors, data processes, and data clusters. Based on the farmers' expectations, the MULTIPASS project stakeholders have proposed the architecture of an ecosystem integrating two consent management tools as "pilots". This ecosystem should take in charge the interoperability between each consent management tools or with future tools. This solution is based on a shared typology of data and data processes as well as on the specifications of the consent message content. All these elements should be easily accessible to meet the interoperability need of the ecosystem. It is also based on a router, which provides unified access to consent management tools (using API). In particular, it provides the farmer (beneficiary) with an exhaustive view of his/her consents (which can be distributed on several consent management systems), meeting farmers' expectations for transparency. It is also the point where a data provider can check whether the consent required to provide data exists, without needing to know which consent management system is concerned. In this project, the stakeholders want to demonstrate to agricultural professional organizations the benefits and feasibility of a consent management ecosystem. By strengthening the confidence of farmers to share data, the project will allow the emergence of new knowledge and new services

Cardiac metabolic deregulation induced by the tyrosine kinase receptor inhibitor sunitinib is rescued by endothelin receptor antagonism

International audienceThe growing field of cardio-oncology addresses the side effects of cancer treatment on the cardiovascular system. Here, we explored the cardiotoxicity of the antiangiogenic therapy, sunitinib, in the mouse heart from a diagnostic and therapeutic perspective. We showed that sunitinib induces an anaerobic switch of cellular metabolism within the myocardium which is associated with the development of myocardial fibrosis and reduced left ventricular ejection fraction as demonstrated by echocardiography. The capacity of positron emission tomography with [ 18 F]fluorodeoxyglucose to detect the changes in cardiac metabolism caused by sunitinib was dependent on fasting status and duration of treatment. Pan proteomic analysis in the myocardium showed that sunitinib induced (i) an early metabolic switch with enhanced glycolysis and reduced oxidative phosphorylation, and (ii) a metabolic failure to use glucose as energy substrate, similar to the insulin resistance found in type 2 diabetes. Co-administration of the endothelin receptor antagonist, macitentan, to sunitinib-treated animals prevented both metabolic defects, restored glucose uptake and cardiac function, and prevented myocardial fibrosis. These results support the endothelin system in mediating the cardiotoxic effects of sunitinib and endothelin receptor antagonism as a potential therapeutic approach to prevent cardiotoxicity. Furthermore, metabolic and functional imaging can monitor the cardiotoxic effects and the benefits of endothelin antagonism in a theranostic approach

Imaging of response to anti-angiogenic drugs

Les nouveaux traitements, comme les molécules antiangiogéniques, agissent sur des cibles spécifiques. Leur effet sur la taille tumorale est parfois absent ou retardé. De nouvelles techniques d’imagerie fonctionnelle s’intéressent à une caractéristique physiologique plutôt que la taille tumorale, et pourraient mettre en évidence des modifications en réponse au traitement apparaissant plus précocement. L’imagerie dynamique de la microcirculation suit la biodistribution d’un agent de contraste, et analyse la vascularisation tumorale. L’imagerie par résonance magnétique pondérée en diffusion permet de distinguer l’eau libre, de l’eau restreinte dans les tissus, reflétant la cellularité tumorale. L’imagerie par résonance magnétique par effet BOLD reflète l’oxygénation tissulaire en quantifiant le rapport déoxy/oxyhémoglobine. Les études testant ces techniques sont cependant préliminaires et nécessitent des études à grande échelle pour évaluer leur rôle dans la réponse aux traitements ciblés en oncologie.New therapies, such as anti-angiogenic drugs, target specific molecules. Their effect on tumor size is sometimes absent or delayed. New techniques of functional imaging do not detect changes in size, but rather a physiological characteristic, and could reveal changes in response to treatment which arise earlier. Dynamic contrast-enhanced (DCE) imaging follows the biodistribution of a contrast agent and analyzes tumor vascularization. Diffusion-weighted magnetic resonance imaging quantifies restriction to diffusion of water in tissues, reflecting tumor cellularity. BOLD magnetic resonance imaging reflects tissue oxygenation by quantifying the ratio between deoxygenated and oxygenated hemoglobin. Studies testing these techniques are still preliminary. It is therefore necessary to organize large scale studies to evaluate their potential role in response to targeted therapies in oncology

IRESite—a tool for the examination of viral and cellular internal ribosome entry sites

The IRESite (http://www.iresite.org) presents carefully curated experimental evidence of many eukaryotic viral and cellular internal ribosome entry site (IRES) regions. At the time of submission, IRESite stored >600 records. The IRESite gradually evolved into a robust tool providing (i) biologically meaningful information regarding the IRESs and their experimental background (including annotation of IRES secondary structures and IRES trans-acting factors) as well as (ii) thorough concluding remarks to stored database entries and regularly updated evaluation of the reported IRES function. A substantial portion of the IRESite data results purely from in-house bioinformatic analyses of currently available sequences, in silico attempts to repeat published cloning experiments, DNA sequencing and restriction endonuclease verification of received plasmid DNA. We also present a newly implemented tool for displaying RNA secondary structures and for searching through the structures currently stored in the database. The supplementary material contains an updated list of reported IRESs

Machine Learning of Multi-Modal Tumor Imaging Reveals Trajectories of Response to Precision Treatment

"Funding: This work received funding from the Cancer Research for Personalized Medicine—CARPEM project (Site de Recherche Intégré sur le Cancer SIRIC), from the Plan Cancer Physicancer (grant C16025KS), and from the Région Ile-de-France. In vivo imaging was performed at the Life Imaging Facility of Université Paris Cité (Plateforme Imageries du Vivant - PIV), supported by France Life Imaging (grant ANR-11-INBS-0006) and Infrastructures Biologie-Santé (IBiSa). Nesrin Mansouri received a scholarship from the Ministère de l’Enseignement Supérieur et de la Recherche. This project received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement no. 101030046 of M. P.-L." "Acknowledgments: The authors thank Laure Fournier, Judith Favier, Charlotte Lussey-Lepoutre,Irène Buvat, Béatrice Berthon and J.M. Udías for rich scientific advice and discussions"The standard assessment of response to cancer treatments is based on gross tumor characteristics, such as tumor size or glycolysis, which provide very indirect information about the effect of precision treatments on the pharmacological targets of tumors. Several advanced imaging modalities allow for the visualization of targeted tumor hallmarks. Descriptors extracted from these images can help establishing new classifications of precision treatment response. We propose a machine learning (ML) framework to analyze metabolic–anatomical–vascular imaging features from positron emission tomography, ultrafast Doppler, and computed tomography in a mouse model of paraganglioma undergoing anti-angiogenic treatment with sunitinib. Imaging features from the follow-up of sunitinib-treated (n = 8, imaged once-per-week/6-weeks) and sham-treated (n = 8, imaged once-per-week/3-weeks) mice groups were dimensionally reduced and analyzed with hierarchical clustering Analysis (HCA). The classes extracted from HCA were used with 10 ML classifiers to find a generalized tumor stage prediction model, which was validated with an independent dataset of sunitinib-treated mice. HCA provided three stages of treatment response that were validated using the best-performing ML classifier. The Gaussian naive Bayes classifier showed the best performance, with a training accuracy of 98.7 and an average area under curve of 100. Our results show that metabolic–anatomical–vascular markers allow defining treatment response trajectories that reflect the efficacy of an anti-angiogenic drug on the tumor target hallmark.Depto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUECancer Research for Personalized Medicine—CARPEM project (Site de Recherche Intégré sur le Cancer SIRIC)Plan Cancer PhysicancerRégion Ile-de-Francee Life Imaging Facility of Université Paris Cité (Plateforme Imageries du Vivant - PIV)France Life ImagingInfrastructures Biologie-Santé (IBiSa)Ministère de l’Enseignement Supérieur et de la RechercheEuropean Union’s Horizon 2020 research and innovation programpu

A conserved structure within the HIV gag open reading frame that controls translation initiation directly recruits the 40S subunit and eIF3

Translation initiation on HIV genomic RNA relies on both cap and Internal Ribosome Entry Site (IRES) dependant mechanisms that are regulated throughout the cell cycle. During a unique phenomenon, the virus recruits initiation complexes through RNA structures located within Gag coding sequence, downstream of the initiation codon. We analyzed initiation complexes paused on the HIV-2 gag IRES and revealed that they contain all the canonical initiation factors except eIF4E and eIF1. We report that eIF3 and the small ribosomal subunit bind HIV RNA within gag open reading frame. We thus propose a novel two step model whereby the initial event is the formation of a ternary eIF3/40S/IRES complex. In a second step, dependent on most of the canonical initiation factors, the complex is rearranged to transfer the ribosome on the initiation codons. The absolute requirement of this large structure for HIV translation defines a new function for a coding region. Moreover, the level of information compaction within this viral genome reveals an additional level of evolutionary constraint on the coding sequence. The conservation of this IRES and its properties in rapidly evolving viruses suggest an important role in the virus life cycle and highlight an attractive new therapeutic target