Fig. 2

Addition of Rba. capsulatus SB1003 to Ana-1 macrophages and 4T1 tumor cells in vitro. Bacteria and mammalian cells were co-incubated at a ratio of 50:1, this being the maximum number of bacteria that can be taken up by one phagocyte. a Schematic of Rhodobacter getting ingested by macrophages resulting in a spectral shift as indicated by the blue and red coloration. b, c OA spectra of Ana-1 cells and supernatant after 24 and 144 h of co-incubation with Rba. capsulatus in comparison with the spectra of pure Rhodobacter. d 24 h data for 4T1 cells. e Representative images of Ana-1 macrophages in the presence of Rhodobacter at 0 and 24 h. After mixing bacterial and macrophage cells free swimming Rhodobacter (a) can be observed, while after 24 h the signal originates predominantly from inside the Ana-1 cells (b) with only a small number of bacteria identifiable outside (c). For 0 h fluorescence was recorded with a mCherry filter set, for 24 h with Cy7. Because of the high motility of Rhodobacter cells, fluorescence and brightfield images do not overlay. The full time course can be found in Supplementary Figure 10. f Fixated sample stained for lysosomal marker Lamp-1 (d, blue) and additionally recorded with Cy7 filter set for fluorescence of disintegrated Rhodobacter (e). Images for the individual channels as well as for the control, Ana-1 without addition of Rba., can be found in Supplementary Figure 11. All scale bars 10 µm