FIG 6.

The S. aureus-triggered cytosolic Ca²⁺ increase leads to a rise of mitochondrial Ca²⁺ concentration and cell lysis. (A, B) HeLa Mito-LAR-Geco G-Geco cells were infected with S. aureus 6850 Cerulean, and changes in mitochondrial and cytosolic Ca²⁺ concentration were monitored by live cell imaging. (A) Representative stills from time-lapse fluorescence microscopy (cyan, S. aureus; red, Mito-LAR-Geco; green, G-Geco; gray, brightfield). Bar, 25 μm. (B) Relative quantification of relative Ca²⁺ concentrations in cytosol and mitochondria of a single infected cell. (C to E) HeLa R-Geco cells were infected with S. aureus 6850 GFP or Cowan 1 GFP strains, and live cell imaging was performed after addition of the fluorescent dye AlexaFluor647 hydrazide. (C) Stills from time-lapse imaging (green, S. aureus; red, R-Geco; magenta, AF64; gray, brightfield). Bar, 50 μm. Relative fluorescence of a single cell infected with S. aureus 6850 (D) or Cowan 1 (E) was quantified over the course of infection.