Figure 8

Rhabdomeric opsin positive cells in the tube feet of Amphiura filiformis, detected by CLSM. Double immunolocalisation of r-opsin (red/hot red) and acetylated alpha-tubulin (green). A. Transmission view of a tube foot (tf) with tip r-opsin positive cells (trop+). B. R-opsin staining shows a cone shaped morphology. C. Cilia (ci) are present along the longitudinal axis of the tube foot. D. Dark areas within the r-opsin positive region indicate location of nuclei. Cilia protrude from the r-opsin positive cells. E. Tube foot proximal r-opsin positive cells (brop+) showing a striated pattern. F. Dense nerve tracts (ntr) but also fine nerve fibers connect to the tube foot nerve ring (tfnr) in the area of proximal r-opsin positive cells. Scale bars in A-D: 10 μm, E-F: 50 μm.