Structural changes of drosopterinosomes (red pigment granules) during the erythrophore differentiation of the frog, Rana japonica, with reference to other pigment-containing organelles

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The number of epidermal melanophores of the skin decreases dramatically during metamorphosis in the frog, Rana japonica. This decrease may represent an adaptation for rapid color change, a property which the animal acquires after metamorphosis. We concluded that the decrease was due to the migration of epidermal melanophores to the dermis. Epidermal melanophores and epidermal cells are tightly associated with each other in the young tadpole. The association becomes looser at the metamorphic stage and, occasionally, small breaks in the basement membrane are seen. These breaks may facilitate the migration. The migration was observed exclusively at the metamorphic stage, in spite of careful observation of other stages under the electron microscope. The migration of epidermal melanophores was induced by treatment with thyroxine of cultured skin from tadpoles at stage 15, and this hormone may act directly on epidermal melanophores. Until now, the increase in the number of dermal melanophores during metamorphosis has been explained by the differentiation of dermal melanophores from melanoblasts and by their mitotic division. Our results show that the migration of epidermal melanophores to the dermis may be a factor which accounts for the increase in the number of dermal melanophores.

Section: Introductionmentioning

confidence: 99%

Migration of Epidermal Melanophores to the Dermis Through the Basement Membrane During Metamorphosis in the Frog, Rana japonica

Yasutomi

1987

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“…They contain types I, 11, and I11 pterinosomes and often present very electron-dense pterinosomes. These latter organelles could be interpreted as melanized pterinosomes, even if, in agreement with Yasutomi and Hama (1973), it is not easy to establish whether a particularly electrondense pterinosome is or is not melanized. In our case fibrils or lamellae arranged concentrically along the periphery were not found in these organelles.…”

Section: Discussionmentioning

confidence: 96%

Pigmentary System of the Adult Alpine Salamander Salamandra atra aurorae (Trevisan, 1982)

Pederzoli

Trevisan

1990

The pigmentary system of skin from adult specimens of the amphibian urodele Salamandra atra aurorae was investigated by light microscope, electron microscope, and biochemical studies. Yellow (dorsum and head) and black (flank and belly) skin was tested. Three chromatophore types are present in yellow skin: xanthophores, iridophores, and melanophores. Xanthophores are located in the epidermis whereas iridophores and melanophores are found in the dermis. Xanthophores contain types I, II, and III pterinosomes. Some pterinosomes are very electron-dense. Black skin has a single type of chromatophore: the melanophores. Some melanophores are located in the epidermis. In contrast to the dermal melanophores, these present, in addition to typical melanosomes, organelles with different morphology and vesicles having a limiting membrane and containing little amorphous material. Both skin types present some pteridines and flavins, though they are qualitatively and quantitatively more abundant in yellow skin extracts.

“…Hcg can be seen generally in many animals (6)(7)(8)(9)(10)(11)(12). However, rcv are reported in only three kinds of animals.…”

Section: Discussionmentioning

confidence: 99%

“…The former are localized in pterinosomes first characterized by Matsumoto (5) and the latter in lipid droplets, the so‐called `carotenoid vesicles' or `carotenoid granules' (4). Pterinosomes are surrounded by a single membrane and often include fibrous or lamellar structures (6, 7). In contrast, no definite membrane is observed around the carotenoid vesicles.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, no definite membrane is observed around the carotenoid vesicles. Sometimes, pterinosomes show a ring structure which makes them difficult to distinguish from some carotenoid vesicles (7). In order to identify definitively the type of vesicle as being either a pterinosome or a carotenoid vesicle, pigments inside the xanthophores need to be identified.…”

Section: Introductionmentioning

confidence: 99%

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An Ultrastructural and Carotenoid Analysis of the Red Ventrum of the Japanese Newt, Cynops pyrrhogaster

Matsui

Marunouchi

Nakamura

2002

The ventral skin of the wild Japanese newt Cynops pyrrhogaster is creamy at metamorphosis, but turns red when mature. The color of the ventral skin of laboratory (lab)-reared newts stays yellow throughout their life. However, the mechanism for the red coloration of this animal still remains unknown. In this study, we have performed ultrastructural and carotenoid analyses of the red ventrum of wild and lab-reared Japanese newts. Using electron microscopy, we observed a number of xanthophores having ring carotenoid vesicles (rcv) and homogenous carotenoid granules (hcg) in the ventral red skin of the wild newt. In the skin, beta-carotene and five other kinds of carotenoids were detected by thin-layer chromatography (TLC). In the ventral yellow skin of lab-reared newts, however, only beta-carotene and three other kinds of carotenoids were found. The total amount of carotenoids in the red skin of the wild adult newt was six times more than that of the yellow skin of the lab-reared newt. Moreover, rcv were more abundant in xanthophores in red skin, but hcg were more abundant in yellow skin. These results, taken together, suggest that the presence of carotenoids in rcv in xanthophores is one of the critical factors for producing the red ventral coloration of the Japanese newt C. pyrrhogaster.