Bdellovibrio

Bdellovibrio - cycle

• B. bacteriovorus
• B. sp ( Various )

Bdellovibrio is a genus of bacteria that includes very small, very fast floating, gram- negative, aerobic, bakterienparasitische species.

They are flagellated monopolar monotrich and swim at a speed of 100 times their body length per second. Bdellovibrien mostly affected gram- negative bacteria, preferably Pseudomonas and Enterobacteriaceae.

Life cycle

The free-swimming individuals of Bdellovibrio attach to the cell wall of their victims, penetrate the cell wall, penetrate into the periplasmic space and then digest the cytoplasm of their host. After propagation through cell division, progeny access by dissolving the cell wall of the host to the outside.

The Capture of host bacteria is facilitated by the Bdellovibrionen can swim very fast. This is achieved in that they have a thicker compared to " normal" bacterial flagella scourge. This allows a greater thrust during locomotion. In conjunction with the small size of Bdellovibrionen in this way reaches very high speeds so that they can reach their prey bacteria easily. The shape of the flagellum is unusual: The proximal portion has a greater height than the body coil handling distant section.

Do the parasites reached their prey, they attach themselves to the surface and perform with the help of their strong scourge rapid rotational movements, which were interpreted as " boring ". Whether really involved mechanical effects in penetrating the prey bacterium that is not secured. Probably pours B. bacteriovorus from a mixture of hydrolytic enzymes localized open the cell wall and allow the intruder to slip into the periplasm of the prey. The resulting hole is then back fully closed. In the periplasm the invaders build with the help of many hydrolytic enzymes and a large number of different transport complexes from the macromolecules in the cytoplasm of the prey and use them as a substrate ( as nutrients ) for its own growth. The parasites grow inside the host up into a cylinder, resulting from the constriction and cell division by many of the same great new single-celled individuals. After cell division and maturation occurs - again by an attack of hydrolytic enzymes - the complete destruction of the prey bacteria and at the same time the release of a most odd number of new B. bacteriovorus individuals.

Genome Research

In 2004, the base sequence of the complete genome of B. bacteriovorus was published by S. Schuster and colleagues. Set derived from the base sequence data over the life cycle of B. bacteriovorus, while they manage to show how it is reflected in the genomic features of the bacterium. For all eight different phases of the life cycle ( perception of prey - attachment - penetration - to set up - Education of Bdelloplasten - cell division - maturation - release ) genes or proteins could be identified that are believed to play a crucial role in each phase. Thus, genes for the formation of the flagellum and various adhesive structures have been identified that are likely to be involved in the first two phases.