Fig. 2From: Optimized fixation of actin filaments for improved indirect immunofluorescence staining of rickettsiaeIndirect immunofluorescent staining of Vero cells infected with R. slovaca and comparison of four fixative solutions. We employed an anti-R. slovaca rabbit serum as primary antibody and goat anti-rabbit Rhodamine Red-X secondary antibody (red fluorescence signal) to probe bacteria. To visualize “comet-tail” formation (in white circles), we applied Alexa Fluor 488 phalloidin for F-actin staining (green fluorescence signal). Rickettsia slovaca formed actin-tails at one pole of the bacterium around 5 µm in length. Likewise, to infected Vero cells with a related intracellular bacterium R. akari, we paralleled fixation step with 3.7% formaldehyde, 4% paraformaldehyde, 4% paraformaldehyde in the cytoskeletal buffer and 4% paraformaldehyde in PHEM buffer. We counterstained nuclei with mounting medium containing DAPI (blue fluorescence signal). Scale bar represents 10 µmBack to article page