Wednesday, 10 May 2017

How bacteria hunt other bacteria

A bacterial species that hunts other bacteria has attracted interest as a potential antibiotic, but exactly how this predator tracks down its prey has not been clear. A new study reveals that the bacterial predator Bdellovibrio bacteriovorus homes in on its target by taking advantage of fluid forces generated by its own swimming movements and those of its prey. These bring the bacteria in close proximity, giving Bdellovibrio bacteriovorus a greater chance of successful attack.

Similar to a virus, Bdellovibrio bacteriovorus attacks bacteria such as Escherichia coli by attaching to and entering its prey, growing and replicating within the cell, and then suddenly bursting out, releasing its progeny into the surrounding environment. Given Bdellovibrio bacteriovorus’ effectiveness at killing pathogens and safety in animal models, some have proposed using the bacterial predator to purify water, degrade biofilms on surfaces, and serve as a living antibiotic in livestock or in humans. Understanding how Bdellovibrio bacteriovorus actually finds its prey is an important first step toward these goals, but until now, whether Bdellovibrio bacteriovorus uses chemical cues to specifically target bacterial cells or bumps into them at random was not known.

Additional experiments showed that Bdellovibrio bacteriovorus preferred to swim near walls and around beads rather than in open waters, suggesting that fluid forces captured them in these hydrodynamic orbits. Moreover, experimental controls, calculations, and computational modeling confirmed that hydrodynamic forces, rather than chemical or electrical cues, were responsible for these effects. Because both Bdellovibrio bacteriovorus and E. coli were subject to their own self-generated fluid forces, both bacterial species co-localized to surfaces, making it much easier for Bdellovibrio bacteriovorus to subsequently collide at random with its prey.

For further details see:

Hossein Jashnsaz, Mohammed Al Juboori, Corey Weistuch, Nicholas Miller, Tyler Nguyen, Viktoria Meyerhoff, Bryan McCoy, Stephanie Perkins, Ross Wallgren, Bruce D. Ray, Konstantinos Tsekouras, Gregory G. Anderson, Steve Press�. Hydrodynamic Hunters. Biophysical Journal, 2017; 112 (6): 1282 DOI: 10.1016/j.bpj.2017.02.011

Posted by Dr. Tim Sandle