Paired FISH images of the SBB allogromiid. (a, b) Paired images of whole specimen showing DAPI (a) and DAPI/CARD-FISH with Cy3-labeled universal Eubacterial probe EUB338I-III (b). (c, d) Paired images of whole specimen showing DAPI (c) and CARD-FISH with Cy3-labeled negative control probe NON338 (d). (e, f) Paired GeneFISH images of lysed allogromiid hybridized to the FITC-labeled Pseudomonas-specific 16S rRNA gene probe (e) and negative control of Texas-Red labeled nirK gene (f) showing some non-specific background hybridization to cellular debris found in close association with some endobiont cells. (g, h) Paired GeneFISH images of another lysed allogromiid hybridized to the FITC-labeled Pseudomonas-specific 16S rRNA gene probe (g) and Texas-Red labeled nirK gene (h). Arrows indicate short chains of coccoid cells in FITC image (g) and coccoid cells in the GeneFISH image (h). Scales: a, c=50 μm; g=20 μm (e–h all same magnification).