• The Korean Journal of Physiology
• /
• v.7 no.2
• /
• pp.59-66
• /
• 1973

It has been reported that vasopressin disperse the melanophore granule of frog skin. The author used hypophysectomized and adrenergic receptor blockaded animals in order to define the mechanism of vasopressin on the melanopore pigment of frog skin. The Rana niglomaculata which could be found in the Seoul area were used on this experiment. The amount of the following drugs were injected into the lymphatic sac of the frog; vaospressin $(0.05\;{\mu}g/g\;B.W.)$, dibenzylin $(0.05\;{\mu}g/g\;B.W.)$, and propranolol $(0.01\;{\mu}g/g\;B.W.)$. The following results were observed; 1. Vasopressin dispersed the melanin granules of melanocyte of frog skin. 2. The melanin granule dispersion activity of vasopressin was observed on the hypophysectomized frog. 3. The melanin granule dispersion was observed on the adrenergic receptor blockaded frog with dibenzylin or propranolol respectively, especially the later one was found to be more obvious. 4. The melanin granule dispersion was observed on the frog which was injected with vasopressin after alpha-receptor or beta-receptor blockade and the later one was found to be more obvious. 5. The melanin granule dispersion was more effective with the blockade of beta-receptor after the treatment with vasopressin on hypophysectomized frog.

• Development and Reproduction
• /
• v.25 no.1
• /
• pp.33-41
• /
• 2021

This study was carried out to observe the development of the autonomous skeletal development of the Favonigobius gymnauchen. Total length (TL) of larvae 3 days after hatching (DAH) were mean TL of 3.34 mm, with a line-shaped parasphenoid ossification in the cranium and basioccipital ossification in the back. The 10 DAH larvae had a mean TL of 5.20 mm, with the number of caudal vertebrae increasing to 15. The urostyle and two hypural bones in the lower part also began to ossify. The 23 DAH juveniles had a mean TL of 8.47 mm. The pectoral girdle's skeleton was completed as the scapula and coracoid were ossified. The pelvic girdle also fully supported the ventral fin as its ossification was completed. Favonigobius gymnauchen and Tridentiger obscurus showed similar characteristics in terms of the anus location of hatched larvae, number of myotomes, and melanophore distribution during the morphological development of the larvae and juveniles. However, this study confirmed differences in the development of the vertebrae and urostyle bone.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.56 no.1
• /
• pp.44-53
• /
• 2023

In this study, the morphological development and early life cycle of larvae and juvenile Rhinogobius brunneus found in Wicheon, Nakdong River, Korea, were investigated. The fertilized eggs were 2.20×0.68 mm (long×short) in diameter. The eggs began hatching approximately 104 h after fertilization at water temperatures of 17.3-20.5℃ (mean 18.9±1.6℃). The newly hatched yolk-sac larvae were 3.71±0.06 mm in total length (TL), with an unopened anus. Three days after hatching, the preflexion larvae were 4.37±0.16 mm in TL with yolk absorption. Twenty days after hatching, the flexion larvae were 6.50±0.22 mm in TL and the tip of the notochord was bent upward. Twenty-seven days after hatching, the postflexion larvae were 11.8±0.63 mm in TL, and the tip of the urostyle was bent at 45°. Forty days after hatching, individuals measured 18.5±0.93 mm in TL and were considered as juveniles as the number of fins became constant for each part. All the postflexion larvae had detached fins. Additionally, the melanophore was observed to be distributed on the head, centrum of the body, and dorsal fin, and there was a difference in the morphology from the water stream.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.56 no.5
• /
• pp.676-683
• /
• 2023

The development of the egg, larvae, and juveniles of Acheilognathus macropterus from the Wicheon stream of Nakdonggang River was investigated for early life history characteristics. The fish used in the study were collected from Wicheon stream located in Bian-myeon, Uiseong-gun, Gyeongsangbuk-do. The fertilized egg was 1.88±0.09 mm (n=30) in long diameter and 1.34±0.06 mm (n=30) in short diameter. After fertilization at a water temperature of 20℃, the egg took 31 h and 40 min to hatch. Newly hatched larvae had an average total length of 3.92±0.13 mm (n=30) and possessed a yolk sac the mouth and anus were not developed. Twenty days after hatching, the postflexion larvae had an average total length of 8.08±0.29 mm (n=30), with the tail tip fully bent at 45° and began feeding. Thirty-three days after hatching, the number of fin stems reached an integer with an average total length of 15.0±1.08 mm (n=30). In this study, differences in the egg size, hatching time, melanophore development period, and distribution location were confirmed between A. macropterus and allied species.

• Korean Journal of Ichthyology
• /
• v.29 no.4
• /
• pp.244-251
• /
• 2017

A total of 15 larvae [3.53~19.49 mm standard length (SL)] belonging to the family Bothidae collected from the southern sea of Korea in 2016 were identified as Psettina tosana based on 434 base-pair sequences of mitochondrial DNA cytochrome c oxidase subunit I. Larvae of Psettina tosana have anterior-most two elongated dorsal fin rays. Uniserial melanophores present on the dorsal and anal fin base, whereas melanophores on the body absent. An inflection point in the relative growth of head length and head depth against SL was shown between 9.93 mm and 10.73 mm SL. The examined larvae of Psettina tosana are clearly distinguished from the most similar species, Psettina iijimae in having no melanophore patches in the proximity of dorsal and anal fin base.

• Fisheries and Aquatic Sciences
• /
• v.14 no.4
• /
• pp.403-410
• /
• 2011

Scartelaos gigas is an amphibious mudskipper species that inhabits mud flats in Korea, China, and Taiwan. This fish is at risk of extinction because of its very restricted habitat and overexploitation. Information about this fish's reproductive characteristics is needed for species conservation. The sexual maturity and early life history of S. gigas were investigated through histological methods and direct observation of eggs in the wild, respectively. In total, 560 individuals of S. gigas were collected with the aid of fishermen from March 2003 to October 2003 at Jung-do Island, southwest Korea. Through microscopic observations of gonadal development, it was determined that S. gigas of both sexes were immature in April, but began to reach maturity in May, and were then fully mature by June, which was maintained until July. In August, some female fish developed early oocytes, but by September oocytes were observed to have degenerated and had been absorbed. Spawned eggs were elliptical and had an average size of 1.37 mm (long axis) by 0.69 mm (short axis). The newly hatched larvae (3.03 mm total length, TL) had an open mouth and anus, two melanophores near the anus, and one large melanophore between the 18th and 19th myomeres. The larvae (3.18 mm TL) showed absorption of the yolk and oil globule within 5 days after hatching and became prelarvae. This species should be considered vulnerable or conservation-dependent, and thus parental fish need to be protected from fishermen during the main spawning season (June).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.40 no.4
• /
• pp.234-242
• /
• 2007

We examined the cause of albinism in a hatchery population of flounder in terms of environmental and nutritional factors, including the effects of light intensity (130-12,300 lux), photoperiod (12L/12D or 24L/0D), tank substrate (concrete or fiber-reinforced polymer), tank color (white or dark green) and supplement with enriched live food, and also compared the growth of normal and albino fry under both 12L/12D and 24L/0D. Further to, normalization of the skin pigmentation pattern on the ocular side has been juvestigated after rearing the albino fry for 2 years after their identification and classification and found that, light intensity did not play a critical role in the development of normal pigmentation or albinism in the flounder. By contrast, the photoperiod was a weak inducer of albinism in the flounder. Tank substrate and color also affected the hypomelanosis on the ocular side of the flounder fry. The choice and supplementation of enriched live foods could drastically reduce the incidence of albinos in hatcheries. On comparing the growth of normal and albino fry, while there was no difference between the groups under 24L/0D, the growth of the albino flounder was slower under 12L/12D. Although coloration resulting from xanthophore and melanophore, but not iridophores, occurred on the ocular side, evidence of albinism remained on the ocular side of flounders.

• Journal of Life Science
• /
• v.28 no.3
• /
• pp.284-292
• /
• 2018

The melanin-concentrating hormone (MCH), a cyclic hypothalamic peptide composed of 17 amino acids, was initially identified in chum salmon (Oncorhynchus keta) as a regulator of pigmentation. Mammalian MCHs are cyclic hypothalamic peptides composed of 19 amino acids that regulate food intake and energy homeostasis. The present study examined not only MCH expression of different tissues but also the melanohore aggregation and intracellular $Ca^{2+}$ influx of fMCH and the other MCH. Real-time qPCR showed that MCH expressed specially in the brain, gonad, and ovary, and expression of MCH was observed during the developmental stages. In the application of synthetic fMCH and both types of synthetic fMCH, dN-fMCH and dC-fMCH, scale melanophore induced significant changes in aggregation activity with various concentrations of MCH. Also, compared to hMCH and sMCH, fMCH exhibited a 36~99.85% increase in relative potency (%), whereas aggregation of dN-fMCH and dC-fMCH remained in a high concentration. However, dispersion was induced rapidly according to be low concentration of dN-fMCH and dC-fMCH. We show that fMCH and its derivates were bound human MCHR1 and rat MCHR expressed in HEK293T cells with nano-molar affinity and are likely to be ligand-induced to mobilize intracellular $Ca^{2+}$. These results may provide new ligands for binding assay with MCHew ligands, as a structure similar to the mammalian MCH structure was discovered in fish. Once the fMCH receptor system is in place, it can be compared to the MCH system of mammals in terms of MCH function.

• The Korean Journal of Zoology
• /
• v.26 no.4
• /
• pp.271-282
• /
• 1983

The authors observed the ultrastructure of the pigment cells of the frog, Rana nigromaculata Hallowell, during the hibernation. The specimens from the skin were fixed in 2.5% glutaraldehyde-paraform-aldehyde fixative in phosphate buffer at pH 7.2 prior to fixation in 2% osimium tetroxide, dehydrated in graded ethanol and acetone, embedded in Epon 812 mixture, and sectioned with LKB-ultramicrotome. the ultrathin sections were contrasted with uranyl acetate and lead citrate and observed with a JEOL-100B electron microscope. The results were as follows. In hibernating phase, pigment cells of the frog were consisted of the three kinds of chromatophores (xanthophore, iridophore and melanophore) in their dorsal skin. The traits of these cells were as follows. 1. Xanthophores A. Xanthophores were filled with pterinosomes and carotenoid vesicles. Many ribosomes, a few mitochondria and glycogen particles were dispersed in the cytoplasm. B. Pterinosomes were spherical or ellipsoidal in shape. They were divided into 6 types (type I, type II, type III, type IV, type V, type VI pterinosomes) by the their inner structure and especially, type I, type II, type III pterinosomes were well developed.

• Korean Journal of Ichthyology
• /
• v.20 no.3
• /
• pp.167-172
• /
• 2008

The Korean bitterling, Acheilognathus signifer (Osteichthyes Cyprinidae), is an endemic and endangered species in Korea. During developmental stages, a small number of oculocutaneous albinism (with colorless body and eyeballs) were observed in the species. In order to investigate histological differences between normal and albinic bitterling, the dorsal skin and choroid-retina of the eyes were taken. The skin and eyes of normal and albino bitterling were similar in structure except for the presence or density of pigment cells. In normal bitterling, the epidermal melanocytes and dermal melanophores were abundantly developed in both the skin and epidermis of the eyes. But in the albino, the dorsal skin had few melanins, and the pigment cells over the choroid-retina pigment epithelium and iris of the eye were very small.