• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.523-529
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• 1992

The GEP endocrine cells of the African clawed toad, Xenopus laevis, were studied immunohistochemically. Five kinds of the endocrine cells were identified in this study A moderated number of 5-HT-immunoreactive cells were detected throughout the gastro intestinal tract, being almost uniform frequency. Gas/CCK -immunoreactive cells were restricted to the basal portion of the pyloric gland and among the duodenal mucosa. A rare glucagon-immunoreactive cells were weakly reacted in the fundic region of the stomach and observed in the exocrine portions of the pancreas. Somatostatine-immunoreactive cells were distributed throughout the gastrointestinal tract with except for the rectum, and not only the periphery of the islets but also the exocrine portions in the pancreas. No CGs- and insulin-immunoreactive cells were found in the gastrointestinal tract, whereas in the pancreas, the later was seen in the central region of the islets and the exocrine portions.

• Korean Journal of Environment and Ecology
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• v.29 no.4
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• pp.525-532
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• 2015

In order to determine the testicular cycle of the Asian toad, Bufo gargarizans, adult males of the species were captured around Jeongeup city (Jeollabuk-do, Korea) during March, 2012 to February, 2013 and the gonadosomatic index (GSI) and the changes of germ cells in their testes were investigated throughout the year. The study indicated that the spermatogenesis in the seminiferous tubule of testes began in April and became most active in July. The recorded GSI was the highest and the cross area of seminiferous tubule was the widest in this period. The seminiferous tubules at the post spawning stage appeared in February, the largest amounts occurred in March and primary spermatogonia also appeared in this period. The GSI and the cross area of seminiferous tubules were found to be the lowest in March, indicating a testicular cycle with potentially continuous spermatogenic process. According to the findings above, it is confirmed that testicular spermatogenesis takes place actively between April to July in male Asian toad and that their breeding season is February to March.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.171.1-171
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• 1996

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
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• 1999.04a
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• pp.55.2-55
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• 1999

No Abstract, See Full Text

• Applied Microscopy
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• v.28 no.3
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• pp.379-390
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• 1998

Dermal wound healing responses in the skin of the toad, Bombina orientalis, were examined using transmission electron microscopy. At 12 hours after wounding, debridement and collagenolysis occurred in damaged dermis. Histocyte has a large nucleus and long cytoplasm process. Phagocytic vesicle and lysosome were observed in the cytoplasm. Damaged blood cells were transformed spindle to irregular shape. Autolysis was observed in their cytoplasm. Histocytes are found in poly-band. The irregularly shaped nucleus is located peripheral region in cytoplasm. At 2 days after wounding, partial aggregation of blood cells is observed. Phagocytic, activity is observed in histocyte and collagenolytic collagen fibers are scattered. Fibroblast is observed in the dermis at 3 days after wounding. Clusters of ribosomes and some short cisternae of rough-surfaced endoplasmic reticulum are found in the cytoplasm. In histocyte at 7 days post wounding, various size granules composed of moderately dense material are found the cytoplasm. In this period histocyte is round to rod in profile, with slender processes projecting from the surface. At 7 day after injury, it was observed that formation of connective tissue fibers and amorphous ground substance in regenerating skin.

• Korean Journal of Veterinary Research
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• v.37 no.1
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• pp.9-13
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• 1997

The gastrointestinal endocrine cells of the African clawed toad, Xenopus laevis have been investigated immunohistochemically using the avidin-biotin method. Seven antisera were tested and three endocrine cell types immunoreacted with antisera to neurotensin, GRP and substance P. A moderate number of neurotensin-immunoreactive cells were weakly reacted in the small intestine. GRP-immunoreactive cells were mainly situated among the upper portion in the fundic glands, and the basal portion in the pyloric glands. These cells were oval and round in shape. On the other hand, in the intestine they were thin spindly cells with the epithelium. Substance P-immunoreactive cells were observed in among intestinal epithelium. However, no secretin-, motilin-, M-Enk- and PYY-immunoreactive cells were found in the GIT of the African clawed toads.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.2
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• pp.87-93
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• 2015

Public education on soil and soil science in Korea was reviewed through textbooks written in Korean which were used in the primary schools since 1950's. Numbers of words 흙[heuk], the Korean native word meaning soil, and 토양[土壤, toyang], originated from Chinese characters, were counted, and compared with the textbooks published in 1950's, 1970's, and 1990's, 2010's. The Korean native word "heuk" was used 20 times in 1950's, and increased to 55 times in 1970's. In 1990's version, it was decreased to 31 times and to 20 times in the 2010's version. The first appearance in the 1950's version was in the 3rd grade book, but was in the $1^{st}$ grade books in both 1990's and 2010's. In this recent version, the primary school students met this word on the poet, "Toad, Toad build a house", and "Sprout come out through soil clod". The word, "토양, toyang", originated from Chinese characters, 土壤, appears only 2 times in the $6^{th}$ grade in 2010's version. Authors conclusively recommend children should learn meaning of soil at early stage of primary school easily with positive image.

• Journal of Wetlands Research
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• v.22 no.1
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• pp.8-14
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• 2020

This study was carried out to compare the Snout-vent length (SVL) and the biomass for the endangered species II, narrow-mouthed toad (Kaloula borealis), at the three different latitude sites (Seoul, Nonsan, Busan) in Korea. For the narrow-mouthed toad study, pitfall traps and inducement traps were used to catch the species, and environmental factors (temperature, precipitation, humidity) were compared by region. As a result of this study, each of the male narrow-mouthed toads' SVL and biomass in Busan was 41.6±0.39mm, and 11.3±0.17g, which showed that it was the biggest and heaviest among the three regions. For Seoul and Nonsan, each of the SVL of the female narrow-mouthed toad was 36.6±2.03mm, 36.6±1.76mm, and the biomass was 8.1±0.55g, 8.2±0.91g, which showed that there was no significant difference between Seoul and Nonsan. Each of the female narrow-mouthed frogs' SVL and biomass in Busan was 44.7±0.35mm, 13.1±0.18g, which was also biggest but showed no significant difference in biomass by region. Concluding, this showed that the female narrow-mouthed toad in Busan is larger and heavier than those of other regions. We hope this study will be a standard for the future amphibian research with comparing the SVL and biomass for the endangered species II, narrow-mouthed toad. It is expected that if this kind of study keeps for long, it will be a basis for understanding changes in biomass of amphibian species due to climate change.

• Korean Journal of Environment and Ecology
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• v.34 no.3
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• pp.207-215
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• 2020

In this experiment, investigated toxicity evaluation of chemicals using Asian toad embryos, along FETAX(Frog Embryo Teratogenesis Assay-Xenopus) protocol. Asian toad, Bufo gargarizans embryo incubated and investigation of Benomyl(Germicide), Carbofuran(Insecticide) and Thiobencarb(Herbicide) effect by probit analysis. As a result, depends on the concentrations of Benomyl, Carbofuran and Thiobencarb, along mortality and malformation rates were increases and larval body length were decreased. The teratogenic concentration(EC₅₀) of Benomyl, Carbofuran and Thiobencarb were 1.03, 8.74, 4.98mg/ℓ, respectively. And when exposed to Benomyl, larvae responded most sensitively to malformations. Embryo lethal concentration (LC₅₀) Benomyl, Carbofuran and Thiobencarb were 7.26, 560.72, 16.87mg/ℓ, respectively. And Benomyl were at the lowest concentration of lethal the embryos. The teratogenic index(TI) were 7.05 in Benomyl, 64.16 in Carbofuran and 3.39 in Thiobencarb, thus TI values were above 1.5, which is the criterion of teratogenicity. Three of the pesticides used in this study were considered to be a teratogenic substances and Carbofuran was the most potent teratogen. And more specific researches are needed to investigate the effects of pesticides on the embryo development of toads and amphibians and their mechanism.

• Korean Journal of Environmental Biology
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• v.26 no.1
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• pp.22-29
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• 2008

Bombina orientalis, or Korean fire-bellied toad is belonging to Class Amphinia, Order Anura, Family Bombinatoridae, Genus Bombina. Ecological characteristics, such as small size, slow moving and swimming, gentle attitude to other species, under laboratory and/or wild condition lead the toad as suitable experimental animals with easy handling. Seasonal reproductive biology except breeding season (usually from Apr. to late Jun.) are unknown still caused by sampling methods for hibernating specimens have not been established yet. Most species of amphibian, include B. orientalis, are declined around the world related with global warming, therefore, wild caught specimen for any purposes must be limited controled soon. Even though, some pre-studies of biotope for increasing biodiversity have been reported, construction of an artificial biotope to get natural breeding cycling specimen for study of amphibian reproduction is unique modelling and only trial. In an effort to set year-round sampling for study of reproduction of B. orientalis, we suggest protocols for planning, construction manual and SOP(Standard Operation Process) to manage amphibian biotope. During pilot operation of a designed and constructed biotope, the seasonal acclimation during winter hibernation of B. orientalis were successful. It will be helpful for studying the reproductive biology of wild amphibians in temperate region and allow to get reasonable research conditions in amphibian laboratory.