Soutenance de thèse : Tools and methods for interactive visualization and analysis of superstructural biological assemblies by cryo-ET : a Deinococcus radiodurans case study

Par Lorenzo Gaifas (IBS/Groupe Imagerie microscopique d’assemblages complexes)

Cryo-electron tomography (cryo-ET) is an imaging technique that allows to reconstruct the three-dimensional volume of whole biological samples - such as cells and tissues - in situ, in near-native conditions and within their biological context.
With the development of direct electron detectors and increased computing power, in recent years cryo-ET has rapidly become a powerful and ubiquitous tool in the arsenals of structural biologists, sometimes capable of reaching sub-nanometer resolution.
Due to the yet immature software ecosystem and the complexity of the workflows, working with cryo-ET data is still error-prone and requires constant human supervision, especially when it comes to subtomogram averaging pipelines attempting to reach high resolution reconstructions.
This thesis presents the development of blik, a tool aimed at simplifying working with cryo-ET data by providing interactive visualisation, analysis and annotation that are both powerful and customizable, with a focus on the analysis of superstructural systems such as filaments and membranes.
Using blik and other tools, we investigate the cell wall composition and septation mechanism in the radiation resistant bacterium Deinococcus radiodurans, and study the structure and role of FtsZ, a tubulin homologue which plays a key role in cell division.