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Updated: Mar 14, 2026

Measuring the Effects of Bacteria and Chemicals on the Intestinal Permeability of Caenorhabditis elegans
Published on: December 3, 2019
A secreted bacterial peptidoglycan hydrolase enhances tolerance to enteric pathogens
Kavita J Rangan1, Virginia A Pedicord2, Yen-Chih Wang3
1Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA. krangan@rockefeller.edu hhang@rockefeller.edu.
Abstract:
The intestinal microbiome modulates host susceptibility to enteric pathogens, but the specific protective factors and mechanisms of individual bacterial species are not fully characterized. We show that secreted antigen A (SagA) from Enterococcus faecium is sufficient to protect Caenorhabditis elegans against Salmonella pathogenesis by promoting pathogen tolerance. The NlpC/p60 peptidoglycan hydrolase activity of SagA is required and generates muramyl-peptide fragments that are sufficient to protect C. elegans against Salmonella pathogenesis in a tol-1-dependent manner. SagA can also be heterologously expressed and secreted to improve the protective activity of probiotics against Salmonella pathogenesis in C. elegans and mice. Our study highlights how protective intestinal bacteria can modify microbial-associated molecular patterns to enhance pathogen tolerance.
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