External Seminar "Bacterial nanotubes extend from a tubeosome organelle to establish an intercellular bridge" by Sigal Ben-Yehuda

Title: Bacterial nanotubes extend from a tubeosome organelle to establish an intercellular bridge

Speaker: Sigal Ben-Yehuda

Affiliation: Department of Microbiology and Molecular Genetics, The Hebrew University of Jerusalem, Israel

Abstract: We have previously identified a novel mode of bacterial communication mediated by nanotubes that bridge neighboring cells. We have demonstrated that nanotubes serve as conduits for intercellular trade of metabolites, antibiotic resistance proteins, toxic proteins, and even non-conjugative plasmids, thus playing a central role in bacterial physiology. However, nanotube formation and dynamics have remained largely unexplored. By combining live-cell imaging with cryo-electron tomography, we describe the biogenesis of nanotubes in Bacillus subtilis. We show that nanotubes form elaborate, dynamic networks, with extending nanotubes exhibiting multidirectional movement toward neighboring cells, scanning their surface for minutes. This process culminates in nanotube penetration and the establishment of an intercellular bridge. Nanotubes emerge within milliseconds from lipid-enriched sites representing a previously unrecognized membranous organelle, which we term “tubeosome”, located in a periplasmic-like space beneath the cell wall. We provide evidence that tubeosomes comprise rolled nanotubes organized in a fire-hose-like structure generated through vesicle chain fusion. Our study uncovers the tubeosome as a novel bacterial organelle and provides the first real-time visualization of intercellular bridge formation in bacteria.