Fig. 5

Visualization of the COTS27 cells in different body parts of COTS using FISH. COTS27 cells (red) residing in the subcuticular spaces of the body walls were detected with COTSsymb, a COTS27-specific probe, in the tips (a) and bases (b) of aboral spines on the discs and arms, respectively, dermal papula (c), pedicellariae on the aboral side (d; 3D image [left] and 3D rendering image [right]), and tube feet (e). Many non-COTS27 bacteria (purple) were detected in the pyloric stomachs (f) using the EUB338mix probe. No visible bacteria were detected in the pyloric caeca (g) and gonads (h) in this study (the images were obtained applying the COTS27-specific probe). The arrowheads indicate signals from COTS27. The green signals are tissue-derived autofluorescence. CU, outer cuticle complex; CYA, cyanobacteria-like cells. Scale bars (a–c and e–h) indicate 20 μm. The 3D image in panel d was taken with an original objective of × 40