A Vibrio cholerae protease needed for killing of Caenorhabditis elegans has a role in protection from natural predator grazing

• Vibrio cholerae is the causal bacterium of the diarrheal disease cholera, and its growth and survival are thought to be curtailed by bacteriovorous predators, e.g., ciliates and flagellates. We explored Caenorhabditis elegans as a test organism after finding that V. cholerae can cause lethal infection of this nematode. By reverse genetics we identified an extracellular protease, the previously uncharacterized PrtV protein, as being necessary for killing. The killing effect is associated with the colonization of bacteria within the Caenorhabditis elegans intestine. We also show that PrtV is essential for V. cholerae in the bacterial survival from grazing by the flagellate Cafeteria roenbergensis and the ciliate Tetrahymena pyriformis. The PrtV protein appears to have an indirect role in the interaction of V. cholerae with mammalian host cells as judged from tests with tight monolayers of human intestinal epithelial cells. Our results demonstrate a key role for PrtV in V. cholerae interaction with grazing predators, and we establish Caenorhabditis elegans as a convenient organism for identification of V. cholerae factors involved in host interactions and environmental persistence.

Nyckelord

Animals

Bacterial Proteins/genetics/metabolism

Biofilms

Caenorhabditis elegans/cytology/microbiology/physiology

Cell Communication

Cell Line; Tumor

Cholera Toxin/metabolism

Feeding Behavior

Fimbriae; Bacterial/metabolism

Humans

Interleukin-8/secretion

Intestines/cytology/microbiology

Peptide Hydrolases/genetics/metabolism

Predatory Behavior

Repressor Proteins/genetics/metabolism

Survival Rate

Trans-Activators/genetics/metabolism

Transcription Factors/genetics/metabolism

Vibrio cholerae/enzymology/genetics/pathogenicity

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