Close-up on how salmonella bacteria punch holes in cells to infect them
When a battle rages on there’s often a decisive moment when the defenders can no longer hold back the invading army, and they break through; a scene that can also be found at a cellular level. The bacterial invader, Salmonella, cause of intestinal infections, pierces the defensive lines of our cell membranes by employing a host of molecular machinery. Researchers have unpicked this mechanism using cryo-electron tomography to image and create 3D reconstructions of Salmonella infecting human cells (left, bacterium coloured green in contact with cell membrane coloured orange). They captured the moment of breakthrough in great detail (seen close up here, right), as Salmonella (green) pushed its needle through the human cell membrane (red), creating a pore (yellow) into which it could inject its proteins. Further experiments at this level of detail will help uncover more about the tactics used by invading bacteria.
Written by Lux Fatimathas
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