Bacteria "Pirate bacterium" hunts with grappling hooks and cannons

The marine bacterium Aureispira hunts its prey with a molecular grappling hook and a kind of cannon. When the hunter attacks its prey, it is reminiscent of a pirate raid on another ship.

Like a pirate ship, the filamentous bacterium swims through the water and waits for its prey to come closer. As soon as there is close contact, the grappling hooks become entangled with the victim's flagella. The Swiss Federal Institute of Technology (ETH) reported that this prevents the prey from escaping.

The bacterium has a kind of bolt gun with which it kills its prey. The cell components that escape from the victim are quickly absorbed by the predator as food. However, Aureispira is only predatory when the nutrient concentration in the environment is low. If the supply of nutrients is sufficient, the pirate bacterium refrains from hunting and reduces its arsenal of weapons.

If the nutrients are lacking, the desire to hunt awakens. The cannons and grappling hooks are restored in the cell, wrote the ETH. This is entirely possible in the vastness of the ocean, as the nutrients required for growth and reproduction are unevenly distributed. This is why a few bacteria developed into efficient hunters.

The ETH researchers used imaging techniques, including light microscopy and cryo-electron microscopy, to uncover how the bacteria work. There are ideas of loading such bacterial bolt guns with active substances and injecting them into individual cells using the molecular machine. Certain predatory bacteria are known to hunt blue-green algae. They could be used to combat algal blooms or to stop the mass proliferation of Vibrio bacteria.