Near Surface Swimming of Salmonella Typhimurium Explains Target-Site Selection and Cooperative Invasion
Spori, Doris M.
- Journal Article
Rights / licenseCreative Commons Attribution 3.0 Unported
Targeting of permissive entry sites is crucial for bacterial infection. The targeting mechanisms are incompletely understood. We have analyzed target-site selection by S. Typhimurium. This enteropathogenic bacterium employs adhesins (e.g. fim) and the type III secretion system 1 (TTSS-1) for host cell binding, the triggering of ruffles and invasion. Typically, S. Typhimurium invasion is focused on a subset of cells and multiple bacteria invade via the same ruffle. It has remained unclear how this is achieved. We have studied target-site selection in tissue culture by time lapse microscopy, movement pattern analysis and modeling. Flagellar motility (but not chemotaxis) was required for reaching the host cell surface in vitro. Subsequently, physical forces trapped the pathogen for ∼1.5–3 s in “near surface swimming”. This increased the local pathogen density and facilitated “scanning” of the host surface topology. We observed transient TTSS-1 and fim-independent “stopping” and irreversible TTSS-1-mediated docking, in particular at sites of prominent topology, i.e. the base of rounded-up cells and membrane ruffles. Our data indicate that target site selection and the cooperative infection of membrane ruffles are attributable to near surface swimming. This mechanism might be of general importance for understanding infection by flagellated bacteria. Show more
Journal / seriesPLoS pathogens
Pages / Article No.
PublisherPublic Library of Science (PLoS)
Organisational unit03644 - Jenny, Patrick / Jenny, Patrick
03589 - Hardt, Wolf-Dietrich / Hardt, Wolf-Dietrich
03640 - Vogel, Viola / Vogel, Viola
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