Role of Motility and the Flhdc Operon in Escherichia Coli Mg1655 Colonization of the Mouse Intestine.
From: Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, USA.
Infection and immunity
- Publish Date: Jul 2007
- ISSN: 0019-9567
- Volume: 75
- Issue: 7
- Pages: 3315-24
- Medium: Print
- Language: English
- Citation (JAMA): Gauger Eric J, Leatham Mary P, Mercado-Lubo Regino, et al. Role of Motility and the Flhdc Operon in Escherichia Coli Mg1655 Colonization of the Mouse Intestine.. Infect. Immun. Jul 2007;75:3315-24
Abstract
Previously, we reported that the mouse intestine selected mutants of Escherichia coli MG1655 that have improved colonizing ability (M. P. Leatham et al., Infect. Immun. 73:8039-8049, 2005). These mutants grew 10 to 20% faster than their parent in mouse cecal mucus in vitro and 15 to 30% faster on several sugars found in the mouse intestine. The mutants were nonmotile and had deletions of various lengths beginning immediately downstream of an IS1 element located within the regulatory region of the flhDC operon, which encodes the master regulator of flagellum biosynthesis, FlhD(4)C(2). Here we show that during intestinal colonization by wild-type E. coli strain MG1655, 45 to 50% of the cells became nonmotile by day 3 after feeding of the strain to mice and between 80 and 90% of the cells were nonmotile by day 15 after feeding. Ten nonmotile mutants isolated from mice were sequenced, and all were found to have flhDC deletions of various lengths. Despite this strong selection, 10 to 20% of the E. coli MG1655 cells remained motile over a 15-day period, suggesting that there is an as-yet-undefined intestinal niche in which motility is an advantage. The deletions appear to be selected in the intestine for two reasons. First, genes unrelated to motility that are normally either directly or indirectly repressed by FlhD(4)C(2) but can contribute to maximum colonizing ability are released from repression. Second, energy normally used to synthesize flagella and turn the flagellar motor is redirected to growth.
Mesh Headings (Keywords): Animals, Cecum, DNA-Binding Proteins, Escherichia coli, Escherichia coli Proteins, Gene Deletion, Gene Expression Regulation, Bacterial, Intestinal Mucosa, Intestine, Small, Intestines, Male, Mice, Operon, Trans-Activators
Check for Full Text / PubMed Unique Identifier (PMID): 17438023
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