Immunohistochemical detection of opsins in turbellarians

Using the antiserum against the C-terminus of opsin of Dugesia japonica, immunohistochemistry revealed that opsins were actually localized in the photoreceptive organs of several turbellarians. The antiserum produced positive reactions in eyes of the Polycladida Notoplana koreana as well as those of the Tricladida Dugesia dorotocephala, Bdellocephala brunnea, Phagocata kawakatsui, Phagocata vivida and Polycelis auriclata, but not to those of Convoluta naikaiensis, Stenostomm sp. and Macrostomum tuba. This suggests that these opsin proteins of triclad and polyclad species have functional similarity in the C-terminus.