title: Integumental reddish-violet coloration owing to novel dichromatic chromatophores in the teleost fish, Pseudochromis diadema.
abstract: In the reddish-violet parts of the skin of the diadema pseudochromis Pseudochromis diadema, we found novel dichromatic chromatophores with a reddish pigment and reflecting platelets. We named these novel cells 'erythro-iridophores'. In standard physiological solution, erythro-iridophores displayed two hues, red and dark violet when viewed with an optical microscope under ordinary transmission light and epi-illumination optics, respectively. Under transmission electron microscopy, however, we observed no typical red chromatosomes, i.e., erythrosomes, in the cytoplasm. High-performance thin-layer chromatography (HPTLC) analysis of the pigment eluted from the erythro-iridophores indicated that carotenoid is the main pigment generating the reddish color. Furthermore, when the irrigating medium was a K(+)-rich saline solution, the color reflected from the erythro-iridophores changed from dark violet to sky blue, but the red coloration remained. The motile activities of the erythro-iridophores may participate in the changes in the reddish-violet shades of the pseudochromis fish.
authors.affiliation: Department of Biophysics, Faculty of Science, Kyoto University, Kyoto, Japan. goda@em.biophys.kyoto-u.ac.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Goda
authors.forename: Mihoko
authors.initials: M
authors.lastname: Ohata
authors.forename: Hayato
authors.initials: H
authors.lastname: Ikoma
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujiyoshi
authors.forename: Masazumi
authors.initials: M
authors.lastname: Sugimoto
authors.forename: Ryozo
authors.initials: R
authors.lastname: Fujii
mesh_terms: D000825:Animal Structures / Q000166:cytology; D000818:Animals; D002856:Chromatophores / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D005399:Fishes / Q000502:physiology*; D034582:Integumentary System / Q000502:physiology*; D012880:Skin Pigmentation / Q000502:physiology*; D016707:Tissue Fixation