Revealing the cell biology of a predatory bacterium in space and time
The model predatory bacterium Bdellovibrio bacteriovorus feeds upon other Gram-negative bacteria, including pathogenic strains. Upon entry inside the periplasmic space of the prey envelope, B. bacteriovorus initiates an exquisite developmental program in which it digests the host resources while ensuring the osmotic stability of its niche. In the periplasm, the predator cell grows as a polyploid filament, before releasing a variable, odd or even number of daughter cells upon a non-binary division event. The progeny is then liberated to hunt for new prey. B. bacteriovorus is now attracting a revived attention as several in vivo models of infection established its promising “living antibiotic” potential. Despite this remarkable lifestyle, the fields of bacterial cell biology and antibiotics research still lack a comprehensive understanding of how this micro-predator thrives inside the envelope of other bacteria. Indeed, the molecular factors behind the non-canonical cell biology of B. bacteriovorus are still largely mysterious. 

My goal is to tackle this question by unraveling the novel mechanisms that control key processes of the fascinating cell cycle of this bacterium, using a unique combination of quantitative live imaging of predation at the single-cell level, bacterial genetics and molecular biology. Specifically, I aim to (i) uncover how the genetic information is organized, copied and partitioned in a polyploid cell before non-binary division, (i) shed light on factors that polarize the predator cell, and (iii) discover prey envelope features that influence the predation cycle. Because the biology of B. bacteriovorus stands beyond textbook standards, our results will provide mechanistic insight into important biological questions that remained unexplored using “classical” model species. If successful, this project will advance bacterial cell biology, while offering an innovative contribution to the fight against antibiotics-resistant pathogens.