Scientists have discovered that a predatory bacterium, capable of invading and controlling harmful insects such as E.coli and Salmonella, can shape its own shape to fit inside its prey.
Scientists at the Universities of Nottingham, Birmingham, and Newcastle, published a new study to clarify that the curved (boomerang-like) shape of the bacteria, calledBdellovibrio bacteriovorus, is an important ingredient in its lifestyle, which allows it to effectively invade, grow, and live inside other bacteria.
A bacterial cell-wall-modifying gene has unique features that allow the bacteria to recreate its own distinctive shape.
Researchers discovered how thebacterium can engulf prey cells without harming themselves by sculpting the prey into a sphere shape using proteins that theBdellovibriosecrete enables the preys to be altered.
TheBdellovibriouse the prey as a food and grow and develop into cells formed like a curved string of boomerang shaped sausages. These separate and then escape and find more prey.
TheBdellovibrio''s bacteriovoruscan is isolated from earth and water around the world and each isolate has the curved shape, but it hasn''t been completely understood why and how they are shaped like this. In this new paper, researchers found that the curved boomerang shape of theBdellovibrio, is produced by a special protein - Bd1075 - that theBdellovibriouses on itself (rather than secreting into predators).
As the prey cells grow, the perturbation of this advanced shaping reduces the speed of prey invasion and affects how theBdellovibriofits interact. Hence, the evolution of Bd1075 has allowed theBdellovibrioto to perform its function effectively in and integrate into the prey cell environment.
Emma Banks and Professor Liz Sockett led the study with Dr Carey Lambert in the School of Life Sciences at the University of Nottingham. They worked with Mauricio Valdivia Delgado from the Professor Andy Loverings lab at the University of Birmingham.
Emma Banks said: "Looking down the microscope and seeing that our colour-tagged Bd1075 shape protein (marked in red on image 2) goes to just one side of theBdellovibriocell (the outer curve) was really cool. When I made certain modifications to the Bd1075 protein, the protein then failed to go to the correct location. This helped us to understand how the protein localises within the curvedBdellovibriocells.
Emma found that cells without the boomerang shape invade prey cells more slowly and extend round the prey cell by growing as straight filaments instead of curved. Bd1075 has made theseinvasions and intracellular life processes more efficient and less likely to fail. Thus theBdellovibrioare aided to successfully replicate inside other bacteria.
Known as "Bd1075," the bacteria, which is simple cells without nerves or brains, have a molecular understanding of their own shape,and of the cell''s shape, and of the spherical prey environment that they grow inside. This technique is quite a feat for a single cell.
Professor Loverings, a teamworker, was working on the structure of the Bd1075 protein at the University of Birmingham.
Professor Lovering said that from previous experiments with otherBdellovibrioproteins, cell wall modification enzymes might be broadened and utilized in unique ways that relate to the predatory lifestyle.
When Mauricio had acquired the structure, we found that Bd1075, comparable to those used in the prey cell, had several significant changes, one of which changed the length and nature of the pocket used to direct its activity to the correct location in the cell.
Microscopy and structural approaches are quite satisfying, and this was certainly the case here: trimming the modified Bd1075 pocket back to a length seen in those other systems completely hampered her normal functioning and, as Emma saw by microscopy, altered the distinctive curved cell shape.
As a team, we always feel grateful to observe the beauty of evolution and the improvements it confers onBdellovibrio bacteriovorus, making it an effective predatory invader of other bacteria. When thinking about how to develop therapeutic invaders to combat pathogens in the future, learning about these techniques is vital.