How do bacteria divide ? At first glance, it might seem simple : one cell splits into two. But behind this universal process lies a fascinating diversity of strategies, shaped by evolution, bacterial morphology and environment.
Deinococcus radiodurans grows as diads (unit of two cells) and divides to form a tetrad (unit of four cells), which rapidly splits into two diads. However, unlike most bacteria, D. radiodurans divides using an unusual “sliding doors” mechanism. This mode of division had been reported in some early studies of D. radiodurans morphology, and when we started our fluorescence imaging experiments using the membrane dye Nile Red, we also observed this intriguing mode of division in which cells divide through the synthesis of two opposing cross-walls that meet and fuse at midcell. To elucidate the molecular mechanisms underlying this unusual division process, we teamed up with the MICA and PG groups at IBS and combined cutting-edge imaging approaches to uncover the complex layered structure of the bacterium’s envelope and showed how the “sliding doors” septa grow, straighten, and fuse (see highlight article).
This study is important not only because it reveals how one of the toughest bacteria on Earth orchestrates its division process, but also because it could inspire new strategies to combat microbes and the growing threat of antibiotic resistance. It also opens new, exciting avenues for research, offering the prospect of further exploring the intricate link between cell division and chromosome segregation.
Collaborations
Irina Gutsche (MICA group, IBS)
Cécile Morlot (PG group, IBS)
Publications
Gaifas L, Kirschner AM, Timmins J, and Gutsche I. Blik is an extensible 3D visualisation tool for the annotation and analysis of cryo-electron tomography data. PLOS Biology (2024). DOI : 10.1371/journal.pbio.3002447
Gaifas L, Kleman JP, Lacroix F, Schexnaydre E, Trouvé J, Morlot C, Sandblad L, Gutsche I & Timmins J. Combining live cell fluorescence imaging with in situ cryo-electron tomography sheds light on the septation process in Deinococcus radiodurans. Proc. Nat. Acad. Sciences (2025) DOI : 10.1073/pnas.2425047122