• Fisheries and Aquatic Sciences
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• v.10 no.2
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• pp.53-59
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• 2007

In order to utilize skin of bullfrog (Rana catesbeiana Shaw) as an alternative source of collagen, we investigated and compared biochemical and physical properties of collagens isolated from bullfrog skin. Two kinds of collagen (BSASC; bullfrog skin acid-soluble collagen and BSPSC; bullfrog skin pepsin-solubilized collagen) were isolated by subsequent treatments with acetic acid and pepsin. The amounts of skin collagen isolated in the subsequent treatments were 7.3% BSASC and 18.2% BSPSC on the basis of lyophilized bullfrog skin weight, respectively. According to the electrophoretic pattern and CM-cellulose column chromatogram, the BSASC has the chain composition of ${\alpha}1{\alpha}2{\alpha}3$ heterotrimer, and the BSPSC consists of two ${\alpha}$ chains of ${\alpha}1{\alpha}2$. In addition, the denaturation temperatures of all collagens tested were ranged from $30^{\circ}C\;to\;38^{\circ}C$. This study suggests that there is a possibility to use bullfrog skin collagen as an alternative source of collagen for industrial purposes, and subsequently it may increase the economical value of the bullfrog.

• Korean Journal of Veterinary Research
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• v.39 no.1
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• pp.20-26
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• 1999

To investigate the regional distribution and relative frequency of the neurotensin-, pancreatic polypeptide(PP)- and gastrin/cholecystokinin(Gas/CCK)-immunoreactive cells in the gastrointestinal tract of the bullfrog(Rana catesbeiana) with developmental stages, group of bullfrogs subdivided into the tadpole with hindlegs, metamorphosed bullfrog with tail, 2 weeks after metamorphosed bullfrog and adult bullfrog, were stained by immunohistochemical methods (PAP methods). Neurotensin-immunoreactive cells were observed from the pylorus of the metamorphosed bullfrog with tail, but these cells were not detected after that periods. PP-immunoreactive cells were detected from the adult bullfrog in the pylorus, duodenum and ileum. These cells were most predominant in the pylorus. Gas/CCK-immunoreactive cells were observed from the adult bullfrog in the pylorus. According to these results, most of immunoreactive cells in the gastrointestinal tract of the bullfrog were appeared after the complete metamorphosed periods, in which the complete differentiation of structure of gastrointestinal tract were occurred, and variable changes of the regional distribution and relative frequency with developmental stages were observed.

• Animal cells and systems
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• v.3 no.1
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• pp.97-102
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• 1999

In order to investigate the regional distribution and relative frequency of the serotonin-, somatostatin- and motilin-immunoreactive cells in the gastrointestinal tract GIT) of the bullfrog (Rana catesbeiana) with developmental stages, group of bullfrogs subdivided into the tadpole with hindlegs, metamorphosed bullfrog with tail, 2 wk after metamorphosed bullfrog and adult bullfrog, were stained by immunohistochemical methods (PAP methods). Multifarious changes of the regional distribution and relative frequency of the gastrointestinal endocrine cells were observed as developmental stages but motilin-immunoreactive cell ere not detected in this study. Serotonin-immunoreactive cells were detected from 2 wk after metamorphosed bullfrog in the whole GIT. The positive cells were predominant in the pylorus regions. In the adult bullfrog, these cells increased in fundus. On the other hand, somatostatin-immunoreactive cells were observed from the tadpole with hindlegs in the stomach regions. In the metamorphosed bullfrog with tail, they were found in the whole GIT except for the ileum, and increased with developmental stages except for rectum. In the rectum, these cells were not detected after that period. Our results show that most of the immunoreactive cells appear from completed metamorphosed periods when the histological structure of GIT is completely differentiated.

• Food Science of Animal Resources
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• v.41 no.6
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• pp.1049-1059
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• 2021

The objective of this study was to evaluate the nutritional content of bullfrog meat from different parts of the animal, including fore-chest, thigh and calf. Bullfrog meat was found to be a rich source of proteins, essential amino acids and minerals, but with a low fat content, compared with other aquatic meat products. There was no significant difference (p>0.05) between thigh and calf in mineral content (K, P, Na, Mg, Ca, Zn, Fe, Cu, and Mn), but the contents of K, P, and Mg were higher in thigh and calf than in the fore-chest (p<0.05). The salt-soluble, water-soluble and insoluble protein bands in sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis, from fore-chest, thigh and calf were similar, with the most abundant bands being 35 kDa (salt-soluble protein), 35-48 kDa (water-soluble protein) and 48 kDa (insoluble protein). The results showed that the insoluble protein content in the fore-chest meat was higher than that in the thigh meat and calf meat, but the salt-soluble protein fraction was the most abundant in thigh meat. These results showed that the nutrients in different parts of bullfrog meat were different.

• Journal of Photoscience
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• v.3 no.3
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• pp.133-136
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• 1996

Calcium modulates the activity of guanylate cyclase and plays a key role in dark and light adaptation in the visual system. We have measured the Ca$^{2+}$, K$^+$ and Na$^+$ concentration in dark and light adapted bullfrog's (Rana catesbeiana) vitreous humor by using the atomic absorption spectrophotometer. The calcium concentration of the light adapted bullfrog's vitreous humor was higher than that of the dark adapted bullfrog's vitreous humor. This means that ion activity between the photoreceptor and vitreous humor side is light dependent and we have found that a Ca$^{2+}$ channel and Na$^+$ - Ca$^{2+}$ exchanger exist in the vitreous humor.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.351-354
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• 2002

The objective of this study was to analyze fatty acid composition in lipids extracted from bullfrogs (Rana catesbeiana Shaw) inhabiting in Korea. Lipid contents in bullfrog legs and bodies were less than 1% (w/w, wet basis) and seasonal variation of the lipid contents was not observed. Lipids in bullfrog legs consisted of 26~31% (w/w) saturated fatty acids, 16~24% monounsaturated fatty acids, and 30~40% polyunsaturated fatty acids. Lipids in bullfrog bodies consisted of 23~28% saturated fatty acids, 29~44% monounsaturated fatty acids, and 16~30% polyunsaturated fatty acids. The major fatty acids in lipids extracted from bullfrogs were palmitic acid, oleic acid, and linoleic acid. Lipids in leg muscles contained 3~8% eicosapentaenoic acid (EPA) and 6~10% docosahexaenoic acid (DHA). Lipids in bodies had 1~3% EPA and 1~3% DHA.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.2
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• pp.33-42
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• 2011

Zinc plays a key role in genetic expression, cell division, and cell growth and is essential for the functions of more than 450 metalloenzyme. There are high concentrations of zinc in pigment epithelium in bullfrog eye. Zinc deficiency causes night blindness and abnormal dark adaptation. The purpose of this study was to identify ERG (electroretinogram) b-wave sensitivity during light and dark adaptation in bullfrog retina after zinc and zinc chelators treatment such as histidine and TSQ (N-(6-methoxy-8-qunolyl)-p-toluenesulfon amide). Especially, we focused whether histidine act as a zinc chelator in the Muller cell. The results of our study are summarized as follows: 1) Both zinc and histidine elevated ERG b-wave amplitude and threshold in Muller cells by accelerating rhodopsin regeneration time and increased a-peak absorbance during light adaptation. 2) TSQ reduced those by prolonging rhodopsin regeneration time and decrement of a-peak absorbance during light adaptation. 3) Zinc shortened rhodopsin regeneration time and prolonged a-peak absorbance. These results suggested that histidine may act as a zinc-mediated transporter in presynaptic Muller cell membrane rather than zinc chelator and acts as a GABA-receptor inhibitor which blocks $Cl^-$ influx to the postsynapse.

• Journal of Photoscience
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• v.6 no.2
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• pp.77-83
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• 1999

Calcium has a variety of functions in neuron and muscle cells and blood clotting, especially in the visual system where dark adapted rods cotransport with Na$\^$+/ into the cell. An influx of Ca$\^$++/ flows out of the cell through the Na$\^$+/-Ca$\^$++/ exchanger. By using a modified Using chamber in order to bring in vivo environment close, we have known that Ca$\^$++/ blocks the activity of guanylate cyclase, in consequence, having an effect on the amplitude of electroretinogram (ERG). We have measured the Ca$\^$++/, K$\^$+/, and Na$\^$+/ concentration in dark and light adapted bullfrog＇s (Rana catesbeiana) vitreous humor. The calcium concentration of the light adapted bullfrog＇s vitreous humor was higher than that of the dark adapted bullfrog＇s vitreous humor This means that ion activity between the photoreceptor and vitreous humor side is light dependent and we have found that a Ca$\^$++/ channel and Ca$\^$++/K$\^$+/ exchanger exist in the vitreous humor side. Taken together permeability of Ca$\^$++/, K$\^$+/ and K$\^$+/ ion internal limiting membrane faced in the vitreous humor side has light-dependent activity during the illumination.

• 한국전자현미경학회:학술대회논문집
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• 1996.05a
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• pp.59-62
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• 1996

• Proceedings of the Zoological Society Korea Conference
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• 1998.04a
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• pp.32-32
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• 1998

No Abstract, See Full Text