September 2017
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Lundi 06/01/2020 IBCP Conf Séminaire externe |
« Role of Electron Microscopy and chemical Cross-Linking/Mass spectrometry in integrative structural biology » | |
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Riccardo PELLARIN (Pasteur Institute, Paris) Invited by C. Grangeasse Due to the limitation of individual techniques such as X-ray crystallography or cryo Electron Microscopy (cryoEM), studies of large macromolecular assemblies have often been tackled by using integrative structural biology approaches. The integrative structural determination uses as much of the relevant biochemical and biophysical data about a macromolecular complex as possible to generate three-dimensional structures, and exploits the mutual synergy and consistency of the datasets in such a way that the resulting model is more informative than the models generated by each individual dataset. Integration of Chemical cross-linking combined with Mass-Spectrometry (XL-MS) and Electron Microscopy (EM) is a powerful strategy to determine the architecture of macromolecular complexes, especially when combined with X-ray crystallography of protein domains or homology modeling. The two methods provide orthogonal structural information. XL-MS probes the proximity of residues, peptides or domains in macromolecular complexes. EM instead allows visualization of entire particles such as cellular components and macromolecular complexes in a form of 2D images or 3D density maps. We recently developed a Bayesian approach to model the structure of a macromolecular system by optimally combining cryo-EM data with and XL-MS. We use Bayesian inference to determine the optimal weight of cryoEM data in integrative structural modeling. The approach models the structure of the system while simultaneously and automatically quantifying the level of noise in the data. By accounting for both data noise and correlation, this approach enables an effective use of cryoEM density maps in integrative structural modeling. |
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Vendredi 10/01/2020 Salle des Thèses CRC Séminaire Externe |
« How to Lie With Graphics? » | |
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Christophe BONTEMPS (Toulouse School of Economics INRA)
Invited by Olivier Gandrillon
Data visualization is a fundamental ingredient of data science as is “forces us to notice what we never expected to see” (Tuckey,1977). Graphical methods have proved for a long time to be powerful tools both for data analysis, when one wants to visually explore a dataset, and for communicating data-based results. As such, data visualization is one of the most widely used tools of statistics, and probably the most popular one.
However, data visualization can create distorted views of the underlying data. Voluntarily, or involuntarily, many students, but also researchers, data analysts, data journalists, etc. make mistakes in their practice of data visualization. The result is that the visual tests performed for data analysis, when the analyst wants to study or question a dataset, can be wrong or misleading. The structure of the data, patterns and (ir)regularities, groups, trends, outliers… may be misunderstood, leading to serious errors in the understanding of the underlying phenomena. Even worse, when used as a tool for communication and, as such, as a visual language, some graphics may present spurious relationships, false proportions and misleading results. In this talk, we show through real-life examples and case studies, how to manipulate some of the principles and rules of data visualization in order to deliberately lie with graphics. Our goal here is not Machiavellian but pedagogical: by showing the power of some (bad) practices, we preach for better ones. |
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Lundi 13/01/2020 IBCP Conf Séminaire Externe |
« Alterations of lipid bilayers under photo-induced oxidation » | |
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Carlos MARQUES (Institut Charles Sadron (CNRS), Strasbourg)
Invited by L. Monticelli
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Lundi 13/01/2020 11H00 Salle des Thèses CRC Séminaire Externe |
“ The role of RNA-binding proteins in abiotic stress” | |
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Claudius MARONDEDZE (PCV Grenoble, France)
Host: F. Monéger
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Jeudi 16/01/2020 13H00 UMR 754 Séminaire externe |
« Bites, Blood & Behavior: biophysical approaches to understanding mosquito blood-feeding behavior » | |
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Dr Felix Hol Team : Insect-Virus Interactions |
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Lundi 20/01/2020 11h Salle des Thèses CRC Séminaire externe |
« Stepwise opening of chromatin domains in the bithorax complex, along the antero-posterioraxis of the fly » | |
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François KARCH University of Geneva
Hosted by Michalis Averof
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Lundi 20/01/2020 11h IBCP Conf Séminaire externe |
« Structure and dynamics of the translocon:ribosome assemblies: The membrane neighborhood matters » | |
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Alexej A. KEDROV (Institute of Biochemistry, Heinrich Heine University Düsseldorf, Germany)
Invited by C. Orelle
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Jeudi 30/01/2020 11H00 Salle des Thèses CRC Séminaire externe
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« Modulation of host response to infection and vaccines in preclinical models » | |
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Roger LE GRAND (CEA-INSERM-Université Paris Saclay)
Hosted by Hélène Dutartre
The objective of the work is to characterize molecular and cellular interactions occurring at different stages of response to vaccines and infections with the aim to identify new approaches for improving efficacy of vaccines immune-therapies. The dynamics of innate and adaptive responses occurring following immunization of NHP have been analysed using a variety of approaches combining in vivo imaging, microscopy, transcriptomic and flow and mass cytometry. Comparison of routes of injection, combination of adjuvants and prime-boost strategies have been used to inform the design of immunization strategies.
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Vendredi 30/01/2020 11h Salle des Thèses CRC Séminaire externe |
« Aberrant cortical tension generates aneuploidy in oocytes through deregulation of myosin-II » | |
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Marie-Emilie TERRET (Collège de France)
Invited by Marie Delattre
Meiosis in human females is error-prone, generating a high basal rate of aneuploid oocytes. Human and mouse oocytes developmental potential can be predicted by their mechanical properties. Their development into blastocysts requires a specific stiffness window. In this study, we combine live cell and computational imaging, laser ablation and biophysical measurements to investigate how deregulation of cortex tension in the oocyte contributes to early developmental failure. We focus on extra-soft cells, the most common defect in a natural population. Using two independent tools to artificially decrease cortical tension and enrich in this subpopulation, we show that chromosome alignment is impaired in extra-soft mouse oocytes, despite normal spindle morphogenesis and dynamics, inducing aneuploidy. Decrease in the intensity of the forces applied to the chromosomes in extra-soft oocytes does not likely contribute to chromosome misalignment. The main cause is a cytoplasmic increase in myosin-II activity that could sterically hinder chromosome capture. We describe here a new mode of generation of aneuploidies that could be very common in oocytes and could contribute to the high aneuploidy rate observed during female meiosis, a leading cause of infertility and congenital disorders.
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