VIBRIO CHOLERAE: The Bacterial Cause of the Disease Cholera
- When Vibrio cholerae bacteria reach the small intestine,
- they need to propel themselves through the thick mucus that lines the small intestine to get to the intestinal walls where they can thrive.
- So they start to produce the hollow cylindrical protein flagellin to make flagella, the cork-screw fibers they rotate to propel themselves through the mucus.
- However, once the cholera bacteria reach the intestinal wall they no longer need the flagella to move.
- In response to the changed chemical surroundings, they stop producing flagellin
- and start producing the toxic proteins
- that give rise to the watery diarrhea
- that carries new generations of V. cholerae bacteria out into the drinking water of the next host.
See Wikipedia for more …
In cholera, a secretion system facilitates the movement of complex proteins (such as the toxin described above) across bacterial membranes.
Using cryo-electron microscopy, [researchers identified] a structural basis for such a secretion mechanism, showing that the barrel-shaped channel appears to contain a gate in between the cholera bacterium’s two outer membranes.
CREDIT: Tamir Gonen (via Janelia Farm)