Fig. 2: Host GSH is required for proper actin-based motility and cell-to-cell spread of R. parkeri.

a Representative images of Vero cells infected with R. parkeri at an MOI of 1 and imaged at 48 hpi. Coverslips were stained with phalloidin to label actin (red) and with an α-Rickettsia antibody (green). 2 mM BSO was added prior to infection overnight prior to infection. Scale bar = 10 μm in BSO treated images. Scale bar = 5 μm in untreated images. b Quantification of actin colocalization on R. parkeri. Each time point is an average of at least 4 separate experiments totaling > 400 bacteria. c Representative images of HMEC-1 cells treated with 2 mM BSO overnight and infected with R. parkeri, at 48 hpi. Coverslips were stained with phalloidin to label actin (red) and with an α-Rickettsia antibody (green). Scale bar = 5 μm. Images in (a) were captured with 63x confocal immunofluorescence microscopy. Images in (c) were captured with 100x confocal microscopy. Images represent 3 independent experiments. d Vero cells were infected with R. parkeri at the indicated dilutions. For treatment of Vero cells, 2 mM BSO was added 16 h prior to infection, removed prior to infection, and again added at 30 mpi. For treatment of R. parkeri with BSO, bacteria were incubated on ice with 2 mM BSO for 15 m prior to infection. Image is representative of three independent experiments, as shown on the right, in which the second dilutions are quantified. Data were compared with a two-way Student’s T-test. Data are expressed as means ± SD.