Mammalian cell culture and infection | Then the co-cultured cells were rigorously washed twice with phosphate buffered saline (PBS) to remove bacteria in suspension, trypsinized to detach mammalian host cells for flow cytometry , fixed with PBS supplemented with 1% formaldehyde, 0.33% BGS and 0.001% of sodium pyruvate and assayed for their GFP signals by flow cytome-try (FACSCanto II, Becton Dickinson). |
Supporting Information | (B) Flow cytometry of bacterial GFP associated with mammalian cells. |
Supporting Information | (D) Flow cytometry detection of surface Bl-integrins. |
Supporting Information | Flow cytometry data for GFP expression. |
The probability of invasin-mediated uptake is invariant | After co-culture of increasing amounts of GFP-expressing E. coli harboring a plasmid permitting arabinose-inducible control of invasin (pBACr-Aralnv) with HeLa cells, flow cytometry was conducted to obtain data shown in Fig 3A. |
The probability of invasin-mediated uptake is invariant | To simplify the data for comparison, a centroid and mean level of Bl-integrins at a given fraction of infected host cells were computationally estimated from each flow cytometry sample at different MOIs (Fig 3B). |
Variability in invasin-mediated bacterial uptake | This property was consistent with flow cytometry measurements (Fig 1B): At intermediate bacterial concentrations, a bimodal distribution of GFP fluorescence arises where within a single population there exist both uninfected cells (i.e. |