Smed-5B1 labels ciliated cells. (A-C) Whole-mount view of intact planarians immunostained with 5B1 (green), and co-labeled with anti-Acetylated Tubulin (magenta) and DAPI (blue) in panel B and anti-Acetylated Tubulin (magenta) in C. (A) 5B1 labels protonephridial tubules. Arrowheads indicate examples of protonephridia. (B) Image of the head region showing that 5B1 labels the protonephridial tubules that are positive for Acetylated Tubulin. Arrows show examples of protonephridia tubules. (C) A higher magnification image of protonephridia. Arrows point to examples of 5B1-labeled tubules. Arrowheads show examples of 5B1 labeling in flame cells. (D) 5B1is shown to label in immediate proximity to anti-Acetylated Tubulin in the dorsal ciliated stripe. Images are maximum intensity projections of optical sections except for in A. The anterior of the animal is to the top in A and B and to the left in D. Scale bars: (A) 200 μm; (B, C) 50 μm; (D) 20 μm.