The work in the platform for ultrastructural microscopy (PFMU) consists of high resolution ultrastructural analysis aimed at answering scientific questions in collaboration with departments of the Pasteur Institute and with other research establishments such as: INSERM, CNRS, laboratories from different Universities, Curie Institute, Necker Hospital, National Center of Reference and the International network of Pasteur Institutes.

Within these projects, new approaches and technologies are implemented or developed to obtain the best performances when answering to specific questions.

The morphological expertise of the platform lies in the following areas :

• The study of the interactions between microorganisms and host cells

• The morphological characterization of microorganisms (bacteria, viruses, parasites)

• The analysis of the morphological organization of biofilms

• The investigation of frozen hydrated specimen such as viruses, bacteria, proteins and liposomes and the study of proteins/liposomes interaction by cryo-electron microscopy.

Technological developments

• Implementation of cryo preparation/new aspects of cryomicroscopy

• “Cryo-scanning” in scanning electron microscopy

• High pressure freezing (cryo-fixation), leading to an improvement of the sample structural preservation

• Cryo-electron microscopy of vitreous sections (CEMOVIS)

• Correlative light/electron microscopy (CLEM)

In addition, the PFMU offers service activities for rapid diagnosis of agents responsible for new emerging diseases.

Within the institute, the PFMU offers training sessions for users to become autonomous in sample preparation as well as in the samples analysis.

Outside the institute, the PFMU participates in the organization of workshops for a wider audience as :

• The CNRS training workshop « electron microscopy and AFM applied to DNA-protein complexes », co-organized with the UMR 8126 of the IGR (Villejuif).

• The CEMOVIS course with the University of Paris-Sud within the multi-level program in the GDR « Structural analysis in Cryo-electron Microscopy ».

• The «License Professionnelle » at the René Descartes univertsity / Industrie pharmaceutique/ biotechnologie on scanning and transmission electron microscopy.

• The microscopy workshop « 7éme journées de formation du réseau des centres communs » in June 2008 (RCCM /CNRS) at Perpignan.

• The Correlative Microscopy Course at the International School of Biophysics « Antonio Borsellino », 36th course, « Multidimensional optical fluorescence microscopy towards nanoscopy  », Ettore Majorana foundation, Erice, Italy

• A practical workshop in the EMBO course « Cell Biology of Host-Pathogen interactions » organized from the department Cell Biology and infection.

Keywords: Scanning and Transmission Electron Microscopy (SEM AND TEM), Ultrastructure, Immunolabeling, Cryosectioning, Cryofixation, Cryomicroscopy, CEMOVIS, Correlative Light/Electron Microscopoy

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