Abstract

Bdellovibrio bacteriovorus is small (0.2 to 0.5 μm wide and 0.5 to 2.5 μm long) Gram-negative bacterium with the distinguishing feature of killing other Gram-negative bacteria including pathogens such as Salmonella Typhimurium, Pseudomonas aeruginosa or Helicobacter pylori. Considering its small cell size, B. bacteriovorus possesses a relatively large genome size (3.8 Mb). The genome encodes a diverse range of hydrolases and proteases (approx. 150) that are involved in killing and digesting the prey. B. bacteriovorus exhibits a biphasic lifestyle: in the free-living attack phase this highly motile bacterium encounters prey and enters to the cell periplasm; in the growth phase B. bacteriovorus degrades the host’s macromolecules using different types of hydrolytic enzymes and uses reaction products to form its own cell structures. When the resources of the host cell are exhausted, the elongated filament synchronously septates to form usually three to six B. bacteriovorus progeny cells. These progeny cells become motile, and then are released into the environment through lysis of the remaining dead host cell. This life cycle takes usually 3-4 hours. Since B. bacteriovorus kills pathogens, it is seen as a living antibiotic, which may provide an alternative to existing antibacterial agents.

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