Fig. 3. Photomicrographs of cells in Fe precipitate samples. (A) Stained with 4',6-diamidino-2-phenylindole (DAPI) (top) and hybridized with probe TF539 for A. ferrooxidans (bottom). (B) Stained with DAPI (top) and hybridized with probe Acdp821 for Acidiphilium spp. (bottom). Scale bar marker: 5 µm.