Pick On Someone Your Own Size

Plesiomonas shigelloides is a toxic bacterium, but the word toxic is not as detrimental as it sounds. It simply pertains to the production of a toxin or poison. This bacterium produces an enterotoxin very similar to the one produced by Vibrio cholerae. This is a heat-labile toxin, meaning it is readily inactivated by heat. Therefore proper cooking of food will destroy this toxin. If the active toxin is ingested, it binds with cells of the intestine, and proceeds to enter the cells. Once inside these cells, the toxin stimulates increased production of an enzyme that disrupts the active transport (shown to right) of electrolytes (Na+ and K+) through the cell membrane. Modifying this process inhibits fluids from entering the cell, so the fluids are then secreted into your intestine. Excess fluid in your intestines combined with little re-absorption occurring leads to diarrhea. Below are some pictures that show the structure of the enterotoxin produced by Vibrio cholerae from two different angles.

Plesiomonas shigelloides also produces cytolysins, which are pore-forming toxins. These pores can then act as channels for proteins. This toxin seems to become active when interacting with eukaryotic cells. However, during an infection, the cytolysins have been observed to act as cytolytic agents, which simply means that they are used to invade the cell. The picture below illustrates the structure of cytolysins.

While these toxins produced by Plesiomonas shigelloides may sound pathologically intimidating, they only cause gastroenteritis. In the grand scheme of things, these are mild toxins. To learn about other poisonous and venomous organisms, visit MultipleOrganisms.net.

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